CA1068149A - Imaging and recording of information using an organo-tellurium compound - Google Patents

Abstract

ABSTRACT

Selected areas of a layer comprising organo-tellurium compound imaging materials, illustrative of which is Bis (1,5-diphenyl-1,3,5-propanetrione) tellurium dichloride, in the presence of a photosensitizer, are subjected to the imag-ing effect of imaging energy, and of development, advantage-ously of developing energy, causing a change in the organo-tellurium imaging material in the imaged areas accompanied by a change in a detectable characteristic of the imaging mater-ials in the imaged areas. The aforesaid imaging material is especially advantageously extended in a matrix of a polymeric or resinous film-forming material. The invention in its generally most advantageous form involves an imaging step employing imaging energy and producing a latent image, followed by a heat development step to produce the detectable recorded information or image.

Description

~ ` - 10~8149 .
Various methods are known for producing ima~es or dupiicates of images. The imaging materials used are, in certain cases, particular inorganic compounds and, in other cases, particular organic compounds. Some of these heretofore known methods employ mixtures of inorganic compounds such as silver halide, or silver salts or copper salts or other metal salts, with various types of organic compounds as sensitizers, in admixture in a film-forming carrier.
The present invention is concerned with a new i~aging system which employs organo-tellurium compounds, that is, image-forming organo-tellurium compounds in which tellurium is linked directly to at least one carbon atom of an organo radical of the organo-tellurium compounds or is complexed with an aromatic amine, said image-forming organo-tellurium compound being of one structure having one detectable characteristic and which i~ capable of undergoing a change3 such as a chemical change, in response to the application of ; energy to produce a material of different structure having ' another detectable characteristic. The organo-tellurium ',~ 20 compounds may take many forms, as will be pointed out below.
'' Particularly advantageous are those which contain at least one carbonyl group in an organic radical or organic radicals of the organo-tellurium compounds. In others of said organo-tellurium compounds, halogen is present in the molecules, and, especially, the halogen is attached directly to a tellurium atom. In still others of said organo-tellurium compounds, there is at least one carbonyl group present in an organo radical and, in addition, halogen is present attached directly : ~ .

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to a telluriu~ atom. In others of said organo~tellurium com-pounds, no carbonyl groups are present in an organo radical, and in such and others of said organo-tellurium compounds no halogen is present. Numerous embodiments of the image-forming organo-tellurium compounds are disclosed hereafter.
In the particularly important embodiments of the inven-tion, the aforesaid image-forming or imaging organo-tellurium compounds are incorporated into a matrix together with a phot~sensitizer (hereafter, for convenience, called "sensiti-zer",) all as is hereafter described in detail. ~he resulting ; combination of materials is formed into a thin film or layer which i8 capable of producing a latent image when subjected to imaging energy as, for instance, actinic radiation or electro~agnetic radiation. The resulting latent image may then readily be developed into an image of excellent contrast by wet development procedures, or by dry development proce-, ~ , .
; dures as, for instance, by subjection to a source of develop-ing energy, generally in the form of or including heat energy.
Accordingly, the invention provides novel teachings and novel articles or compositions for producing records of re-trievable information, for instance images and duplicates of exi~ting images, which are predicated on a layer which com-prises image-forming or imaging organo-tellurium compounds, which are of one structure and have one detectable character-istic and which are capable of undergoing a change in response to the application of imaging energy to produce a material of different structure, having another detectable characteristic, and which difference in detectable characteristics may be .
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The material having a different structure and different detectable characteristics, resulting from the imaging step, `
will sometimes hereinafter be called the image former.
As will be discussed in further detall below, i~ has been found that organo-tellurium compounds possess certain proper-ties which adapt them especially for use in imaging processes.
Notable is the fact that, as a result of the imaging and devel- .
opment steps, described hereafter, metallic tellurium is de- :
posited from the organo-tellurium compounds. WhiIe tellurium i~ not actually a metal, it does have some metallic character-istics and acts as a metal in some respects~ and in some ;; :
instances the deposited tellurium is referred to herein as ~` , metallic~.tellurium. Tellurium is chain forming in character : and it is generally deposited from the organo-tellurium com-: pounds in chain form, which preferably includes thin needles, which are capable of rapid nucleation and growth of crysta.l-lites, which crystallites grow as chains and largely or mainly .~ as needles. Such chains or needles are opaque and are characterized by excellent li~ht-scattering properties, and . ......... they produce optical densities which are observed after thermal :
or other development; and such effects as may involve oxide . formation are substantially restricted to surface effects as : distlnguished from causiDg degradation through the bodies of , said chains or needles.
,~ As noted above, among the imaging organo-tellurium.com-.. pounds utilized in the practice of the pre~ent invention are those which comprise organic compounds which contain in the molecules an organo radical, tellurium and halogen attached directly to the tellurium atom, there being at least one car~

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81~9 ~onyl group in an oxgano radical, Ce~tain of them are adducts of tellurium halides~ notably tellurium tetrachloride~ with organic compounds, notably ketones or similar chromophores, containing at least one carbonyl group in the organic com- ' pound. This particular group of imaging compounds may, thus, be considered or characterized as organo-tellurium compounds or adducts containing halogen, namely, chlorine, bromine, iodine, and fluorine, attached directly to the tellurium atom.
Most of this particular group of said imaging compounds have two carbonyl-containing organo radicals and some ~f ~hem contain three carbonyl-containing organo radicals. Those which are particularly useful in the practice of the present invention have chlorine as the halogen but, in certain cases, although generally less satisfactory, other halogens can be present. The imaging compounds should be selected to be soluble or homogeneously dispersible in any particular matrix ; material which may be utilized, as i~ described hereafter.
Many of this group of imaging organo-tellurium compounds may be represented by the formula Rx-Te-Haly where R is an organo radical containing at least one carbonyl group, Hal is halogen, especially chlorine, x is 1, 2 or 3 and x plus y equal ~, sub;ect to the proviso that y is 2 when x is 2 and y is 3 when x is 1, and Te is linked directly to carbon in an organo radical. The R radical can be aliphatic, cycloaliphatic or aromatic (mononuclear or dinuclear), ~

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`or a combination thereof and can contain one or ~o~e hetero atoms in the chain or rings. It can be unsu~stituted or substituted, illustrative of such substituents being Cl-C6 alkyl, corresponding oxyalkyl radicals, acetyl, nitro, C N, Cl, Br, F, etc. Generally speaking, the aforesaid organo-tellurium imaging compounds which contaln a trihalide group as, for instance, acetophenone tellurium trichloride, tend to have relatively low melting poin~s (~70- ~80C), and are more ; hygroscopic and less stable than Ithose generally similar com-pound8 containing two halogen atoms and, therefore, such trihalides are less desirable for use in the practice of the present invention.
A more limited class of this particular group of imaging organo-tellurium compounds may be represented by the formula .
(Ar-CO-CH2)2 Te Hal2 ..
where Ar is an aromatic hydrocarbon radical, which may be sub-stituted or unsubstituted, as indicated above, and Hal is hal-~ .
i ogen, especially chlorine. This group of compounds~ partic-; 20 ularly where Hal is chlorine, represents especially advanta-geous embodiments of the invention, with respect to the imag-ing organo-tellurium compounds which are used in the practice of the present invention.
Among the imaging organo-tellurium compounds which do not contain a carbonyl group in an organo radical are tellurium tetrahalide adducts .

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10ti8~3 of aromatic amines in ~hich nitrogen linked o~ attached di-rectly or indirectly to the aromatic radical is substituted by alkyls each containing from 1 to 4 carbon atoms. Numbers ~ :
of illustrative examples of such compounds are disclosed here-after. -:
Still another group of imaging organo-tellurium compounds which do not contain a carbonyl group in an organo radical but in which tellurium is linked directly to carbon are compounds which may be considered or characterized as tellurium tetrahal-ide adducts of ethylenic or of acetylenic hydrocarbons. These compounds are generally conveniently produced by reacting 1 to

2 moles, particularly 2 moles, of the ethylenic or acetylenic hydrocarbon with 1 mole of tellurium tetrahalide, especially preferred for such use being TeC14. Certain of such compounds can be represented by the formula .~ ' ' .
Hal Hal R Te- R ----Hal Hal and : 20 .:
(Hal-R)m Te Haln where R and Rl are each the residue of an ethylenic hydro- ~
carbon, for instance, an alkene or a cycloalkene, Hal is -~ :
chlorine, bromine or iodine, especially chlorine, m is 1 to 2 and n is 1 to 3 with the proviso that the sum of m and n is 4. Illustrative of the ethylenic and acetylenic hydrocarbons ,: ' ~7~ -' ' '~

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lO~;Bl~9 with can be adducted with tell~iu~ tetFahalides to produce , such imaging organo-~tellurium compounds are propylene; butene-.. . . .
l; isobutylene; butene-2; 2,3-dimethyl~2~butene; 3,3~dimethyl- -l-butene; 2,4-dimethyl-1-pentene; 4,4-dimethyl-l-pentene; 2,5-dimethyl-3-hexene; dipentene; l,l-diphenylethylene; l-hep~ene;
l-hexene; 2-methyl-l-hexene; 3-methyl-1-hexene; 4-methyl-1-hexene; 2-ethyl-l-hexene; 2-isopropyl-1-hexene; 2-methyl-1-pentene; 2-methyl-2-pentene; 2-ethyl-2-pentene; 3-methyl-1-pentene; piperylene; vinylcyclohexene; vinylcyclopentene;

2-vinyl naphthalene; 1,2,4-trivinylcyclohexene; 4-methyl-1-cyclohexene; 3-methyl-1-cyclohexene; l-methyl-l-cyclohexene;
l-methyl-l-cyclopentene; cycloheptene; cyclopentene; cyclo-hexene; 4,4-dimethyl-l-cyclohexene; 2-methylbutene-1, 3-methyl-butene-l and l-octene; lo~er alkyl and lower alkoxy deriva~
tives of variou~ of the alkenes Ruch as cyclohexene; l-pentyne;
2-pentyne; l-hexyne and 3 methyl-l-butyne.
The preparation of various of said organo-tellurium com-pounds by adducting ethylenic or acetylenic hydrocarbons or alkenes or alkynes with tellurium tetrahalides is disclosed 2~ in such references as the following: M. DeMoura Campos and ;
N. Petragnani, Tetrahedron, 18,521 tl962); M. Ogawa, Bull, Chem. Soc. Japan, 41,3031 (1968); H. Funk and W. Wei86, J.
Prakt. Chem. 1,33 (1954); and W. V. Parrar and J. M. Gulland, J. Chem. Soc., 11 (1945).
Still others of said imaging organo-tellurium compounds possess in their molecules neither a carbonyl group in an organo radical, nor halogen, nor halogen linked directly to tellurium, as will be seen hereafter.

, ~ bm/~) 8 ~ ~9 ~ The followlng are illustrative examples of the foregoing imaging materials;
: (1) (C6H5COCH2)2TeCl2 ~
(2) (p-C2H50C6H4COCH2)2TeClz : ~ .

(3) (p-CH3C6H4COCHz)2Tecl2

(4) (p-CNC6H4COCH2)2TeCl2

(5) (CH3COC6H4COCH2)2TeClz

(6) (02NC6H4COCH2)2TeCl2 : (7) (cloH7cocH2)2Tecl2 (8) p-CH30C6H4Te(Cl2)CH2COC6H3 C-CH2-Te-CH2-C - Q
O Cl O
(10) (CH3COCH2)2TeCl2 (11) ((CH3)3CCOCHz)2Tecl2 . (12) (C2H5COCHCH3)TeCl3 . (13) (C6H~COCHCOCH3)TeCl3 ! (14) (C 6 H,COCH 2 ~ TeCl3 :; (15) (o-CH30C6H4COCH2)2TeCl2 `~
- (16) COCH~ 2TeCl , (17~ ( C ~ COC~ TeCl2 . (18) (p-F C6H4COCH2)2TeCl2 . .
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lV~8:~9 (19) ( ~ CO ~ leCl~

(20) ( ~ CO ~ TeCl~

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(22) ~ CDC ~ TeCl~

; (23) ( 0 ~ ) 2TeCl2 O O O
:

(24) C ~ _ CN-CH-CO~ ,TeCl, (25) ~ ~ C-CH ~ 0 3 TeCl2 :
(26) (C2H~-C-CH2-f-C2H,)2TeCl2 O O
. (27) (C3H~-C-CH2-C-C3H~)2TeBr2 O O
(28) (CH 3 -C-CH 2 -C-CH3)2T e C 1 2 Il 11 O O

TeCl:

(30) ~ CHCl `\
H2C CHz\
TeCl2 H2C\ / CH2 \ ,CH2 2 n-, ':

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., e : (36) (c6~s)3c-Te3cll3 (373 ~ 0 ~

(38) ((CH3)2N C6H,)2TeCl4 (39) ((C2H~)2N C6Hs)2Tecl4 (40) ((C3H~)2N C6Ha)2Tecl4 (41)~ H3) 2N C6--~
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_~- (42) ~ H3 N~ c6H5 ) TeCl4 2H~ ~ 2 (43) (C6H,N2C6H4N(CH3) 2) 2TeC14 (44) (C6H5NzC6H4 (c2H~)~)2Tecl4 : (45) ~ CH ~
,~ ~ (c6H5N2c6H4N ~ )TeCl4 (46) ((CH3)2N C6H5) 2 TeC12Br2 ~ (47) ((CH3)2N c6H~)2TeBr4 ;~ (48) (C6H,N2C6H4N (CH3) 2) 2TeClzBr (49) (C6H,CH2N(CH~) 2) 2TeC14 ; (50) ~ H, CH C6 ~
. ~ ¦ )TeCl4 ~ N(CH3 ~

(51) ((CH3)2NC6H5)2TeI4 (52) ((c2H~)2Nc6H~)TeF4 (53~ ~ Cl ~1 (54) . fl Cl-CH2-CH2.-Te-CH2-CH2-Cl Cl '-~ , .

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Cl (56) (C6H5COCHzCOCHCOC6Hy) 2TeCl2 ~ .
(57) Cl / Cl ~Te~
~ ' - ,:, (58) (p-Br-C6E4COCH2)2TeCl2 :
(59) (p-I-c6H4cocH2)2Tecl2 ; ~60) ((CHg)2NC6H4COC6H4N (CH3))2TeCl4 . ~-(61) ((C3H,)2NC6H4COC6H4N(C3H,))2TeCl4 :: . .. .
~ (62) ((C2H5~2NC6H4COC6U4N (C2H~) )2TeCl4 .,., ~ ',.

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10~i8~L49 (63) Cl Cl O
Rl R2 wherein Rl and R2 are Cl-C4 alkyl, or cycloalkyl such as cyclohexyl.
: (64) Cl C2H, ~C_ 1 TeCl3 (65) ;, CH-CH2-CH2-Te-CH2-CH-CH2 0/ 11 1 C~0 ~ \~

(66) CH2 H2f fH2 :. T <
Cl Cl The use of the.foregoing examples of illustrative compounds in the form of their corresponding bromides and iodides, is also encompassed within the scope of the present invention, the chlorides, however, at least in most cases being distinctly ~ preferred.

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yarious o~ the f,oregoing compounds are per se known com-pounds although thelr utillty for the purposes of the present invention has not heretofore been known or suggested. Others ; of said compounds, so far as we are aware, have not heretofore be~n known or prepared.
Compounds exemplified by Example (1), ~or instance, can conveniently be prepared by the procedures disclosed by Rust (Ber. 1897, 80,2833~, and G. T. Morgan and 0. C. Elvins, J. C. S.
1925, 2625, or modifications thereof. Thus the compound of Example (1), Bis(acetophenone) tellurium dichloride, is desir-: .
ably prepared by the following procedure:
Acetophenone (5.0 g), and tellurium tetrachloride (5.6 g) in benzene (60ml? and chloroform (40 ml) ane stirred at room temperature for 5 hours. At the end of the reaction time the ; solvent is removed by rotary evaporation with evolution of HCl. The mixture is concentrated to a volume of 20 ml, then methylene chloride (5ml) is added. Addition of diethyl ether (50 ml) to the mixture and standing gives a first crop of whi~e, crystalline needles m.p. 188-190C.
`~ 20 Compounds exemplified, for instance9 by Example (14) are desirably prepared by the following procedure:
Acetophenone (2.4 g, 2 x 10 moles) and tellurium tetra-chloride (5.4 g, 2 x 10 moles) in chloroform (50 ml) are stirred for 1 hour. When 70% of the solvent is removed, yel-low hygroscopic prisms are formed, having a melting point of 75-78C.
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"- 10~ ,9 ; Additional im~ging ~aterials of the ~rst group~ which can be used in accordance with the present invention are sO-called "yellow" compounds or adducts resulting from reacting ketones with tellurium halides, notably tellurium tetrachlo-ride, an example of which is the following:
- (63) "Yellow" compound from Bis(acetophenone) tellurium dichloride synthesis Acetophenone (5.0 8) and tellurium tetrachloride (5.6 g) in 25 ml CHC13 are stlrred at room temperature. After 70 hours the solvent is removed and a viscous greenish yellow oil remains. The oil is dissolved in methylene chloride (10 ml) and diethyl ether (50 ml). On standing, orange prisms come out. Yield 3.3 g, m.p. 132-134C; I.R. (KBr3 1600 cm 1590. Elemental analysis observed; C = 42.22, 42.24; H ~ 3.27, 2.98; Te - 15.30, Cl ' 23.50. The reaction can be accelerated by refluxing the above reaction mixture. However, in such case, distinctly impure products, including Bis(acetophenone) tellurium dichloride, are formed.
It will be noted that this "yellow" compound appears to be reIated to the previously described Bis(acetophenone) ; tellurium dichloride. However, it is a distinctly different material having 8 very substantially different melting point and is made by carrying out the reaction for a very much longer period than that used in producing the Bis(acetophenone) ~ellurium dichoride which latter is in the form of white, ~; crystalline needles having a melting point of 188-190 C.

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i831 ~9 , : The "yellow" compound, as such~ ls.sensitlYe in a range up to about 550 nm and, thus, includes the visible range. In gen-eral, with the "yellow" variants of the imaging materials, it is desirable to utilize developing temperatures somewhat lower .`~ :
than those most desirably used with the non-yellow variants.
Thus, by way of ~llustration, if a developing temperature of 150~ C is substantially optimum for a specified period of time using, say, white Bis(acetophenone) tellurium dichloride as the imaging material, in con~unction with a separate or ~.
extraneous æensitizer, a somewhat lower developing temperature, for instance, 120C, may sometimes desirably be.used with the "yellow" variants of said...imaging material so.as to reduce .
fogging effects in the developed image. Generally speaking, this ~yellow" variant has less latitude in the thermal develop-ment step than the purified white compound.
; Compound t64), as noted above, is a "self-sensitized"
imaging material which i8 operative in the visible range with-out the necessity of utilizing a separate sensitizer. How-ever, if desired, separate sensitizers can be added thereto.
.~ 20 (68) "Yellow" adduct from Bis(2-acetylthiophene) ellurium dichloride synthesis -:` In preparation of the "white" Bis(2-acetylthiophene) ~ tellurium dichloride (see Example (9)) in which 2~acetylthio--.. phene is reacted with tellurium tetrachloride, which is pro-duced by the general procedure referred to above for the pro-. duction of "white" Bis~acetophenone) tellurium dichloride, a reaction time of about 5 hours is employed. In the produc-tion of the "yellow" variant of Bis(2-acetylthiophene) tel-.~ lurium dichloride, a reaction time of 60 hours, under stirring ' ~
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g ~onditions~ a~ x~om temper~t~re i~ used as a result of which a brown solution results. On standing7 o~ange crystals form from 1.0 g ketone and 1/2 equivalent of TeC14 having a melting point o~ 142-145 C; 0.66 g I.R. (KBr) 1575 cm and 1515.
In contrast thereto, the "white" compound of Example (9) has a melting point of 184-185 C. The "yellow" adduc~ from 2-acetylth~ophene and tellurium tetrachloride has a sensitivity in the range up to about 550 ~m or slightly higher.
Compounds (60) and (61), for instance, among others, are "self-sensitized" imaging compounds which are operative in the visible range without the necessity of utilizing a separate sensitizer.
The imaging compounds of the present invention can also be present in the form of organo-tellurium polymers. Thus, for instance, acetophenone tellurium trichloride and analogous or slmilar imaging compounds, disclosed above, can be condensed with polymer ketones, such as acetylpolystyrene, acetyl-methyl-polystyrene and polyvinyl methyl ketone, illustrative of which is the following:
(69) Acetophenone tellurium trichloride (3.0g, 8~5 x 10 3 mole) and acetylpolystyrene (0.6g, 4.0 x 10 mole) in chloro-form are stirred for 2 hours. Removal of the solvent gives a J
solid which is then washed with diethyl ether. This solid darkens at 175C and decomposes at 190-200C. This and simi-lar polymers can have variable molecular weights, the polymers . . .
from which they are produced, such as acetylpolystyrene, ~;

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. commonly having molecular weights generally ~n the range of about 2,000 to about 30,000, but which may be somewhat lower or very substantially ,higher. The finished polymers can serve not only as imaging compounds but, in certain cases, ~.
dually as the matrix or in admixture with other imaging com- : ~
pounds and/or other matrix materials for the achievement of ~.
: the objectives and in accordance with the teachings of the present invention.
At least in many,. if not in most, cases, if th~ organo-tellurium compound is of a character such that, when heated to its melting temperature and maintained at such temperature for a reasonable period of time, it decomposes to produce . metallic tellurium, then it will be useful as an imaging material when employed under the conditions and for the purposes of the present invention. Such organo-tellurium compound~ are, for the purposes of the present invention, characterized generically as "imaging organo-tellurium materials".
Many of the imaging organo-tellurium materials described ; above as, for instance, those of Examples (1), (2), (3), (4), (15), (16), (17), and numerous others, although, for conven-~ ience, designated herein as imaging organo-tellurium materials, require the utilization in conjunction therewith of a sensitizer iII order to produce a latent image when subjected to imaging : energy or actinic irradiation, such as ultraviolet light or visible light, or other forms of imaging energy. In certain cases, and as has been indicated above, impurities ,`' ' :
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1(~i1~9 present as a result of the commercial manufacture of the - imaging or~ano-tellurium materials function as sensitizers.
Thus, for instance, in the production of Bis(acetophenone) tellurium dichloride, acetophenone is commonly present as an impurity and it functions as a sensitizer. Pure Bis(aceto-phenone) tellurium dichloride is essentially light insensitive.
In certain other instances some breakdown of a~ imaging material for instance, through hydrolysis, produces two species of degradation products, one of which can function as a sensitizer and the other as a source of tellurium. In other cases, and in generally predominately the number of cases, a separate sensitizer is required to be added in order to produce a latent image or a sufficient latent image upon exposure of the imaging material to imaging energy which thereafter, on development by exposure, for instance, to dry heat, or by wet development, or by a combination of wet development and heat, results in production of the final image.
The matrix materials, into which the imaglng organo-tellurium materials, and the separate sensitizers when employed, "! 20 are incorporated to produce the imaging film or coating, are ,, :
; solids at room temperature, and they can be selected from a relatively large number of materials. They should desirably ~; be at least in part of amorphous character and it is especially desirable that they be glassy, polar amorphous materials having ; a glass transition temperature, which desirably should not exceed about 200C and may be as low as '' -' .
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about 50C, and , better still, should be within the range of about 80-120C. They are generally polymeric materials.
Illustra~ive thereof are cyanoethylated starches, celluloses and amyloses having a degree of substitu~ion of cyanoethylation of > 2; polyvinyl-benzophenone; polyvinylidene chloride; poly-ethylene terephthalate ("MYLAR"~); cellulose esters and ethers such as cellulose acetate, cellulose propionate, cellulose butyrate, methyl cellulose, ethyl cellulose~ hydroxy-propyl cellulose; polyvinylcarbazole; polyvinyl chloride; polyvinyl methyl ketone; polyvinyl alcohol; polyvinylpyrrolidone; poly-vinyl methyl ether; polyacrylic and polym~thacrylic alkyl egters such as polymethyl methacrylate and polyethyl methacrylate;
copolymer of polyvinyl methyl ether and maleic anyhdride;
various grades of polyvinyl formal resins such as so-called 12/85, 6/95 E, 15/9S S, 15/95 E, B-79, B-98, and the like, sold under the trademark "FORMVAR" - (Monsanto Company).
Of especial utility is polyvinyl formal 15/95 E which is~ ;
a white, free flowing powder having a molecular weight in the range of 24,000 - 40,000 and a formal content expressed as %
polyvinyl formal of approximately 82%, possessing high thermal ., stability, excellent mechanical durability, and resistance to such materials as aliphatic hydrocarbons, and mineral, animal and vegetable oils.
These polymeric materials or resins and their preparation are well known to the art. In addition to their functioning as carriers far and holding together in a unitary composition , .
the imaging organo-tellurium materials, .~, ~ 30 : .
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- ~1068~
; ~~ sen~itizers and any other ingredients which may be incorporated - into the imaging film or coating or layer and their functioning as dry or essentially d~ry film-forming materials to ~rovide thin films and providing mechanical durability in the finished imaged film, at least many of them appear also to play a chemical or physical role in the imaging process by providing, importantly, a source of readily easily abstractable hydrogen and, thus, appear to play a significant role in the latent image formation mechanism, as discussed hereafter. In certain instances, it may be desirable to decrease the viscosity of the matrix, which can be done, by way of illustration, by the addi~ion of certain plasticizers, for instance, dibutyl-phthalate or diphenylphthalate, which additions tend to result in the production of images desirably of higher optical den-sities but which, however, also tend to have the disadvantage of increasing background fogging.
It may be noted that matrix materials of the type which ; contain basic groups may complex with the imaging organo-tellurium materials and, therefore, to the extent that such complexing may occur, the use of such matrix materials should :. .
be avoided.
., .:
The sensitizers which are useful in the practice of the ; present inventlon can be selected from a large group. They ; should be soluble or homogeneously dispersible in the matrix material. Their selection for use in any particular imaging compositions is influenced, in part, by the spectral sensi- -.", , .
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tivity ranges desired. Thus, for instance, in the case of ultraviolet (UV) and visible sensitizers, the following are illustrative of those which can be employed and their approx-imate spectral sensitivity range (nm):

Spectral Sensitivity Sensitizer Range (nm) 9,10 phenanthrenequinone 200 - 400 - 500 U.V. Visible l,l'-dibenzoylferrocene 400-600 l-phenyl-1,2-propanedione 400-S00 :
1 0 , , 2-hydroxy-1,4-naphthoquinone 400-500 Benzil 400-450 : Furil 400-480 Diacetylferrocene 400-450 Acetylferrocene 400-450 : 1,4-bis(phenyl glyoxal) benzene 400-500 0-Naphthoquinone Up to about 560 4,5-Pyrinequinone Up to about 530 ; 4,5,9,10-Pyrinequinone Up to aboue 550 . In the practice of the present invention, 9,10-phen- ~ 20 anthrenequinone is especially satisfactory.
:, i , . The following are illustrative sensitizers which are sensitive in the range up to about 400 nm and, therefore, are useful only in the ultraviolet range: benzophenone; aceto-phenone; 1,5-diphenyl-1,3,5-pentanetrione; ninhydrin ; ~,4'-' ~ -23-' , ' ' ' ' 81~

dibr'omobenzophenone and 1~8-dichloroanth~aquinone.
Yarious other sensitizers can be' utilized, particularly those of the type of substituted or unsubstituted polynuclear quinones, of which class some have'been mentioned above, and others of which are 1,2-benzanthraquinone; 2-methylanthra~
quinone; l-chloroanthraquinone; 7,8,9,10-tetrahydronaphtha-cenequinone; 9,10-anthraqulnone and 1-4-dimethylanthraquinone.
It will be understood that not all sensitizers will be ' effective or equally effective, with each given organo-tellurium imaging material, even taking into account the utilization of imaging energy in the nm sensitivity range of the sensitizer employed and that suitable selections of combi- ' nations of particular organo-tellurium imaging materials and ; particular sensitizers will be required to be made for achiev-ing desirable or optimum results. Such selections, however, can be made relatively readily.
'' In general, in connection with the foregoing matters, it .' may be noted that sensitizers have n,~* states, both singlet ;. and triplet, of lower energies than~,~* states and, at least :
in most cases, compounds which have their ~,~* states of low-est energy wiIl not be photosensitively effective, although, in certain limited cases, compounds which fulfill the test of having lower energy n~* than ~* transitions do not fonction ' as photosensitive reactants. However, the above consideration ~ is, in the main, an effective one for determining in advance '' whether a given compound will function as a photosensitizer .. ~ .
, .

: :

bm/~'~
- ,,,~, . :
.. ' ' - . ~ : ~. . ' 8~ 9 . .
for use in the practice of the present invention. In any event, a simple preliminary empirical test in any given in-stance can readily be carried out if desired.
For imaging purposes where a transparency is to be pro-duced or where the image is to be detected by reflection viewing, it is, at times, preferred that both the matrix of amorphous material and the imaging organo-tellurium material are transparent or at least translucent and have little or no color. On the other hand it may be desirable to provide some color in the layer of imaging organo-tellur~um material so as to favor the absorption of energy of a certain wave length.
- ~ Hence, the sensitizers which are utilized can be selected to reflect the desiderata involved. Thus, they can be of a type which are colored, or of a type which decompose to form color-less and transparent or translucent decomposition products.
In the imaging compositions, the proportions of the matrix, the imsglng organo-tellurium materlal and the sensitizer are variable. In those special cases where the imaging organo-tellurium material utilized is one whlch also inherently or concomitantly possesses desired sensitizing properties, as noted above, a separate sensitizer is not necessary. It may, however, even in such cases, be desirable to employ a separate -or added sensitizer which may be of entirely different sensi-tizing properties from that inherently possessed by the part-icular imaging organo-tellurium material utilized. In any event, generally speaking, excluding the organic solvent or .:.

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10~81~9 solvents, where emp~oyed as described below, at least in most eases the matrix material, which is a normally solid material, that is, solid at room temperature, will be employed in amounts in excess of any one of the other materials and will also usually be present in major amount, that is, more than 50% and broadly in the range up to 90% preferably about 60 to 70%, by weight, of the total materials present in the imaging composition. The imaging organo-tellurium material, generally also a normally solid material, will usually or commonly be the next largest ingredient, and will ordinarily constitute from about 5 to 7 to about 30%, usually about 10 or 15 to 20%, by weight of the imaging composition. The sensitizer, where it is a separate ingredient, which is usually a solid but may be a liquid at room temperature, will usually be employed in lesser proportions, commonly of the order of about 5 to 20%, usually about 6 to 15%, by weight, of the imaging composition, although, in certain cases the proportions thereof can be substantially higher, approximately or even exceeding some-. .
what the proportions of the imaging organo-tellurium material.
Again, and with further regard to the proportions of the aforesaid ingredients, it may be sta~ed that the area density of the sensitizer, for instance, the 9,10-phenanthrenequinone, is desirably selected 80 that about 80% of the photons falling on the film in the region of the absorption bands of 9,10-phenanthrenequinone are absorbed. Considerably higher concen-trations of 9,10-phenanthrenequinone would leave the dark side . ~ "
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of the film unexposed and no advantage would thus be 6erved.
Again, in general and for optimal results in many cases, the mole concentration of the imaging organo-tellurium material should be reasonably close to or roughly approximate that of the sensitizer. The concentration of the polymer matrix material should be sufficien~ to produce an essentially amor-phous film without bringing about precipitation of the imaging organo-tellurium material, the sensiti~er and other supplemen-tal ingredients when utilized. Excess polymer matrix material 0 al80 tends to decrease the sensitivity of the film.
In certain cases, it may be desirable to include in the imaging composition, additional or supplemental materials for obtaining certain or special effects. Thus, for example, it has been found that certain materials enhance the shelf life of unexposed virgin dry film compositions of the present ln vention and, in certain instances, also, they enhance the sensitivity of said film compositions. Illustrative embodi-i ments of such additional or supplemental materials, which con-tain ether or polyether linkages in the molecules thereof, are such materials or polymers as polyethylene-20 sorbitan mono-. laurate; polyethylene-20 sorbitan monooleate; Polyox-10; Polyox-80; Polyox_750; polyethylene glycol-400 distearate; polyethylene glycol-600 distearate; poly (1,3-dioxolane); poly (tetrahydro-furan); poly (1,3-dioxepane); poly (1,3-dioxane); polyacetal-dehydes; polyoxymethylenes; fatty acid esters of polyoxy-methylenes; poly (cyclohexane methylene oxide); poly (4-methyl- -~''., .
.

.

; -27-bm . . .
.- . . ~,, 8~g 1~3~dioxane)j polyoxetanes~ polyphenylene oxides; poly ~3,3-bis (halomethyl) oxocyclobutane~; poly (oxypropylene) glycol epoxy resins; and copolymers of propylene oxides and styrene oxideis. Such materials can be incorporated in the imaging film compositions in varying amounts, generally from 5 to 20%
by weight of the soLid imaging film compositions. In certain cases they enhance or prolong the shelf life or storage life, under given storage conditions, as much as 50% or even very substantially more timewise, and, as indicated, they also, in var~ous cases, effectively increase film sensitivity.
Again, the inclusion in the imaging films of reducing -sugars has been found, generally speaking, to bring about an enhanceme~it in density of the image area (0. D. image-0. D.
, .
background), when the film is imaged as disclosed above and then developed, for instance, at about 120-150C and for of the order of about 15 seconds, especially where the imaging film is freshly prepared or not older than about a day after initial preparation. Such films, when exposed to imaging energy and then developed resulted in the production of a positive image (i.e. the optical denslty is greater in the non-- exposed areas than in the exposed areas) in contrast to the negative working s~stem which exists in the usual practice of the present invention. The inclusion of reducing sugars in th~ lmaging compositions also enables development of the image, after exposure to imaging energy, to take place at lower temperature, even at room temperatures, in a perlad of ,,, ~

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t;8i~9 ;~ several hours~ for instance~ co~monly in 10~12 or 15 hours.

The reducing sugars whic~ can be employed are many, illustra- -. . , ~ tive of which are dextrose, glucose, arabinose, erythrose, , - fructose, galactose, fucose, mannose and ribose. Especially effective are dextrose, arabinosej galactose, fucose and ribose. The reducing sugars can be used in variable amounts, but generally in equivalent amounts, or somewhat smaller or greater, in relation to the amount of imaging organo-tellurium materials in the imaging compositions.
In the production of the films or thin layers of the lmaging material compositions, which are generally prepared in the form of solutions or homogeneous dispersions and coated or laid down on a substrate, it is especially desirable to dissolve or homogeneously disperse the lngredients in an or-ganic solvent. Illustrative of suitable solvents are dimethyl-formamide (DMF), chloroform, tetrahydrofuran (THF), dimethyl-acetamide (DMA), dioxane dichloromethane and ethylene dichloride, or compatible mlxtures of such organic solvents or with other organic solvents. After the solution or homogeneous dispersion is filmed on a substrate in any suitable manner, the ma~or proportions of such organic solvent or solvents are evaporated off, preferably at a relatively low temperature ; and, sometimes desirably, under subatmospheric pressures or in vacuo, until the film or coating is substantially dry to the touch, such dry to the touch coating being especially ... .
desirable for handling and processing purposes. Although such films or coatings may be, generally speaking, dry to the touch, it should be understood that this does not mean that the film is free from organic solvent. Indeed, it has been .

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found that it is fre~ently yery de~ixable that the finished , films or coatings, prlor to exposure to imaging energy, con-tain a small percentage, commonly of the general order of about 2 to 3~, by weight of the film or coating, or organic solvent, for instance, dimethylformamide (DMF) since its presence appears to play a favorable role in the sensitivity of the system in relation to the latent image formation andtor ultimate image Dbtained after the development step. The elim~
ination of all or essentially all of the DMF, or other organic solvent or solvents, from the virgin film prior to the imaging and development frequently leads to a decrease in sensivity.
In any event, in any given instance where drying of the virgin imaBing film has been carried out to a point where essentially no organic solvent is present, and whereby sensitivity is unduly reduced, sensitivity can be increased or restored by adding a small amount of organic solvent to the film prior ! to exposing it to imaging energy.
The imaging film or coating thickness are variable but will usually fall within the range of about 1 to about 35~m with about 5 to 15~m generally being a good average. In thickness in terms of millimeters (mm), such may vary from ; about 0.0005 to about 0.05mm, or much greater such as from 0.05 to 5mm, the selected thickness being dependent upon the partlcular use to which the imaging film is to be put.
, The production of the imaging organo-tellurium materials, and the coating, handling and processing operations, to the .. .

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.
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10~;81~9 - - - -- - -.
extent wllich may be required, are carried out under approprl-ate light conditlons, as those skilled in the art will readily understand. Eor instance, the formulation of the coating com-positlons and the coating and drylng operations are conven--iently carried out under amberlite filtered light (weak trans-mission at 550 nm~. The dry film prior to imaging, is deslr-- ~
ably stored in the dark. In certain cases, avoldance of -contact of certain of the ingredients with certain metals may be in order where undesired reactions, such as reductions, may occur. In general, the vessels~or containers, stirrers, etc. utilized should be made of glass or other vitreous materials or other materials inert to the coating ingredients to insure against contamination or possible undesired reac-tions. It is advantageous, in general, to prepare the imaging compositions shortly prior to coating them on the selected substrate. Under suitable storage conditions, which generally are conditions of darkness and reasonable avoidance of air or oxidizing atmospheres and humidity conditions, the stability , - of the imaging compositions is good. Adverse and unduly pro-longed storage. however, adversely affects speed and contrast in the production of the images.
, In the utilization of the imaging films or 1ayers of the present invention, they are subjected, for instance, through . a suitable or desired mask, to imaging energy which may, for instance, be by actinic light~ irradiation with u~traviolet . ~ - - .

. ' . ' ' ' ' , ' ' ~ , ' :

, , ;. ' ' , ' ,' ' . . ' ' ' .
,,' ' ' ' ' ' ' ` :~068i'~9 .
light or by visible light, depenaing, for exampl~, upon th~ -specific imaging organo-tellu-rium material and the specific sensitizer utilized, to form a latent lmage-wh~ch is normally not visible to the naked eye. In an illustrative case, for instance, in Example D below, illuminating with a Xenon lamp, the total flux delivered to the film surface may be in the general range of 3 x 105 to 106 ergs/cm of film. The sub-. : ~
sequent development, to develop or bring out the latent image, is most desirably effected by the application of heat, for .. :
example, at a temperature of about 130-160 C, preferably about 150 C, for several seconds, say 3 to 15 or 20 seconds, or wet development, or a combination of heat and wet develop-ment. Heat or thermal development can be effected by various means such as a hot plate, hot mineral oil, or hot silicone . oil, at the aforementioned temperatures, or an infrared lamp.
The result is to produce a dark image having, for example, an .. ~ . , . :optical density (O D.) of 1, in the area of exposure only, the background remaining generally relatively light or clear. -In the development step, only a small percentage of the ~20 total imaging organo-tellurium material which is present in the matrix composition is reduced to metallic tellurium. After t~e development, the film or layer may be, and desirably is, .. . .. ... .
. subjected to a ~ixing step which serves to effect removal of the sensitizer and to inactivate the unreacted imaging organo-tellurium material. While this can be accomplished in various ways, a particularly effective procedure is to contact the - ' :- - .
' ',; ~ , -.. ..
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.

film, by washiny or wiping with, or spreading on, or dipping in, chloroform/toluene (20:80 by volume~ solution-saturated , with ammonia or with organic amines.- This removes the sensi-.~ , .
tizer and, of course, the color thereof, and inactivates the imaging organo-telLurium material so that no lmage will form with subsequent exposure and heating and, thus, stabilizes the film. Organic amines such as trimethylamine, triethylamine, diethylamine, triisopropylamine, aniline and benzylamine (e.g. 10% solutions), are illustrative of those which can be utilized. Particularly when fixed, the film does not darken, generally speaking, unless subjected to somewhat elevated ; temperatures as, for instance, of-the order of about 90 to ,, lOOoC. - ' ~
:. - .
The following examples are illustrative of the production o films or layers made in accordance with the present inven-.
tion. Th~y are not to be construed ln any way as limitative of the invention since many other films or layers can be made in light of the guiding principles and teachlngs contained harein.

: , .
.. . .
20 Example A --- , -5Q mg Bis(acetophenone) tellurium dichloride, 250 mg '~ polyvinyl formal ("FORMVAR" 15/95 E), 20 mg o-~apthoquinone ;~ and 3 ml DMF are stirred together at room temperature until a homogeneous yellow viscous solution is obtained. It is then poured onto a 3" x 4" sheet of "MYhAR" to form a film or layer - - ' . - :
:~ -,, , ~0~8~L~g of a thic~ness of about 10,~ and then heated in an oven at 50 C for about 30-45,minutes, at whlch tlme the film or layer is dry-to-the-touch. If desired, although in no way necessary, the dried film may be preheated for 3 to 5 seconds at 150 C
which results in cross-linking the polymers whereby to render the matrix more impervious to water. -.
- Example B -~ -Example A is carried out as described therein except that chlorofor~ is used in~place of DMF. The film is-dried in a well ventilated hood for 30 minutes at room temperature to form a dry-to-the-touch film. --~
- . . .
.
Exam~_e C ~ ~ -Example A is carried out as described therein except that, in place of the DMF, a mixture of DMF and chloroform is used in volume ratio of 20% DMF - 80~o chloroform. A dry-to-the-touch film is obtained. ~ - - ~

Example D -50 mg Bis(acetophenone) tellurium dichloride, 250 mg poly-vinyl formal ("FORMVAR" 15/95 E), 50 mg benzophenone and 3 ml DMF are stirred together at room temperature until a homo-geneous viscous solution is obtained. ~It is then poured onto a sheet of ~MYLAR~ and dried, as described in Example A, to form a clear, dry-to-the-touch film.

.

' , ' ; ' ~: ~ . ' : ` ' ' - ' ~
' -34- -' - ' ' : '. ' _...... .. ..... ,, . ,.. . . , ~
.

.
Example E
: . . .
- 50 mg acetophenone tellurium trichloride, 250 mg poly- -.
vinyl formal ("E'ORMVAR" 15/95 E), 20-mg 4,5-Pyrinequinone and ~ 3 ml DMF are ad~ixed and coated onto "MYLAR" and heated to - form a clear dry-to-the-touch film, in the manner described .. . .
~ in Example A.
- : ~ . . . .
Example F -40 mg Bis(p-methylacetophenone) tellurium dichloride, 200 mg cyanoethylated starch, 16 mg 4,5,9,10-Pyrinequinone and 2.8 . .
ml DMF are stirred together at room temperature until a homo-geneous viscous solution is obtained. It is then poured onto ; a 3" x 4" sheet of "MYLAR" to form a film or layer of a :
thickness of about 10~ and then heated in an oven at-50 C
for about 30-45 minutes, at which time the film or layer is dry-to-the-touch.
, Example G
~- 2 g of the compound of Example (15) are mixed with 5 g .
of cyanoethylated starch and dissolved in about lOO parts by ~- weight of acetone. The solution is deposited on a glass plate to form, after drying, a film of about 10 m thickness.~

Example H
Example A is carried out as described therein except that, - .: . .
; in place of the use of the imaging organo-tellurium material ~- of Example A, the imaging organo-tellurium material of Example :' .
. .
? ~ -35-38 is utilized.

Example I ~ - ~- - . ~
''. ' ' : .
50 mg of the compound of Example (l) above, 250-mg poly-vinyl formal ~"FORMVAR" 15/9S E), 20 mg 9,10-Phenanthrenequi-none and 41 mg DMF are stirred together at room temperature until a homogeneous viscous solution is obtained~ It is then .
poured onto a sheet of "MYLAR" to form a film having a thick-ness of about 3~m and dried, as described in Example A, to - form a dry-to-the-touch film. ~ ~

ExamPle J
.
- 52 mg Bis(acetophenone) tellurium dichloride, 260 mg .
polyvinyl formal ("FORMVAR" 15/95 E), 22 mg g,10-phenanthrene-quinone and 3 ml DMF are stirred together at room temperature until a homogeneous yellow viscous solution is obtained. It ": . .
is then poured onto a 3" x 4" sheet of "MYLAR" to form a . . . . , . ~ .
yellow, clear film or layer of a thickness of about 8,~m, and : ~ then heated in an oven at 50 C for about 30-45 minutes, at - - which time the film or layer is dry-to-the-touch. , !~ -~: Example K ~ :
;, . . . .
35 mg Bis(p-methylacetophenone) tellurium dichloride, 185 mg polyvinyl formal ("FORMVAR" 15/95 E), 14 mg 9,10-phenan-threnequinone and 2.5 ml of 70:30 DMF-chloroform are stirred .
together at room temperature until a-homogeneous yellow viscous solution is obtained. It is then poured onto a 3" x 4" sheet - . . ~' ' ' ' ~' "
- : :
. . :

- , .

681~g - ~ --of "MYLAR" to form a yellow, clear film or layer of a thic~n~ss ~
of about lO~m, and then heated in an oven-at 40 C for-about -, - .
~ 30-45 minutes, at which time the film or layer is dry-to-the-touch.

; . Example L
~ 16 mg Bistacetophenone) tellurium dichloride, 77.6 mg :, :
. polyvinyl formal ("FORMVAR" 15/95 E), 6.7 mg 9,10-phenanthrene-- quinone and 3 ml of a solution of 5 parts by volume of DMF and : - 1 part by volume of chloroform are stirred together at room i 10 temperature until a homogeneous yellow viscous solution is obtained. It is coated on a MYLAR substrate and heated as :;
described in Example J.
-. 25 mg Bis(acetophenone) tellurium dichloride, 125 mg poly-: .
vinyl formal ("FORMVAR" 15/95 E), 50 mg polyoxyethylene (20) sorbitan monolaurate, 7 mg 9,10-phenanthrenequinone and 3 ml ' : of a solution of DMF and chloroform, as described in Example :
.: : . .
: L, are stirred together at room temperature until a homo~
. : - - , :~ : geneous yellow viscous solution is obtained, which is then -20 coated on a Mylar substrate and heated as descrlbed in Example J.
:, . . _ . : :~ ~, .
: - . : ~
.Examele N
.. , ~ , An imaging composition is made using 0.050g of compound (1), 0.020g of 9,10-phenanthreneguinone, 0.25g polyvinyl . .. ~ .
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.
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- 10~81~9 .
.
formal ("E'ORMV~R" 15/~5 ~) and DMF/dichloromethane-2.25/0.75 ~ ml. The composition is coated uniformly onto a sheet of -~
- , - - ~' ~
"MYLAR" having an area of 12 square inches and dried at 50 C ~ ~
- . ~
for 45 minutes. It is then imaged by expo~ure to a xenon flash from a type 700 Honeywell flash gun for about 2m sec.
.
It is then exposed by subjecting it to a heat lamp at 150 C -for 20 seconds to produce a visible image with good contrast.
:
~ The invent~ion will be further illustrated in connection ., .
~; with the accompanying drawings in which~
: . . - ~ :- .
~ Fig. 1 is a schematical fragmentary cross-sectional repre-, - sentation of a starting structure of the invention comprising .
a layer containing an imaging organo-tellurium material and i being selectively subjected to imaging energy through an open--ing in a mask.
, - .
Fig. 2 is similar to Fig. 1, indicating the latent image, , . . .
thoùgh not visible to the naked eye, formed by the selective . _ ,, . ..................... . : -application o imaging energy.
.~
Fig. 3 is similar to Fig. 2 but showing the mask removed -; and development energy being applled to the structure.
20Fig. 4 is simiiar to Fig. 1 but showing the structure fully developed.
- . -Fig. 5 is a schematic representation of a photomicrograph ~-showing in a 2000X enlargement a portion of an area containing a deposit of crystalline image formeF
.
Referring to the drawings, the structure shown in Fig. 1 comprises a substrate 12 such as glassJ~n which lS deposited - - : - :
.
.
- ~ ` , - .

.
- ': ' - - ' , . . . . .

- 10t;81'~Y
a thin, light transmissive layer 14 comprlsing a matrix o~- a glassy, amorphous material such as polyvinyl formal and dls- ~-tributed thereln an imaging organo-tellurium material and a sensitizer, as shown, for instance, in illustrative Examples A-N, inclusive. Upon the layer 14 of the structure is placed an imaging mask 16 comprising opa~ue areas 18 and light trans-missive area 20. Electromagnetic radiation or actinic light 22 is shown falling through light transmissive area 20 of the mask onto the portion of layer 14 underlying area 20 of the mask.
The radiation is being applied in form of a short pulse. In Fig. 2 is shown the structure of Pig. 1 after termination of the application of electromagnetic radiation. In layer 14 is indicated by small wavy lines the presence of latent image 24, even though, as pointed out above, ~this latent image is gen-erally not visible to the naked eye.
.. .
In ~ig. 3-is shown the structure of Fig. 2, with latent image 24 in the center section of layer 14. The mask 16 has ~ -been removed. The structure is shown suspended above the source 26 of radiant heat energy, such as an electrical heater, ~ ' . : . . . .
20the temperature of which is controlled in the deslred range, for instance, 130-150C. Radiant heat energy 28 is shown ~o pass through substrate 12 to heat up the layer ~4. As layer 14 is being heated a chemical reaction takes place in the area ~ .containing the latent image 24, whereby the tellurium of the above-mentioned imaging material is set free from its bonding : . . . : , in the compound (1) and precipitated in elementary form in -39_ ` ~
";' ~ '', ,1. ' ' . ' -.,''' ' ~ . : ~
'' ' . ' ~ '' ~ 10~81~9- ~

-layer 14. -~*~ tellurium is present in the area correspondillg to the latent image 24 in the layer 14 in form of needles or needle crystallites of very small size. The structure as it appears after completion of the heating step is shown in ~lg.
:
4 comprising an opaque section 30 in the center, where the radiation strikes layer 14, and light transmissive section 3 representing the areas pro~ected by the opaque areas 18 of mask 16 (Fig. l) from the radiation.

-If the su~strate 12 is light transmissive or transparent,lO such as glass, upon viewing through the structure, area 30 is dark or essentially non-transmissive for light, while areas 32 are highly light transmissive. Such structure, therefore, renresents a transparency.
If the substrate 12 is a non-transparent but ~ighly reflec-tive material such as white paper and layer 14 is originally light transmissive, upon viewing, area 32 will appear white and show the reflectance of the paper, while area 30 is non-reflective appearing dark or black upon reflective viewing. ;
The separation line at 34 in the structure of Flg. 4 is20 photographed at an enlargement of 2000X. The appearan~ of the photomicrograph so obtained is sche~atically represented in Fig. 5. The separation line of trans~arent and opaque areas is indicated by the arrow at 34. To the left in the light transmissive area 32 appear no ~r only a few larger crystals 35 of tellurium while to the right clouds of small particles 36 can be seen. By visual inspe~tion under the microscope it is seen that there are scattered particles of tellurium , , I : - ' , ' . ~
.
'.

.

,` . 10~1~9 - ~ ~
needles in the layer 14 whic'h produce the opaqueness of area 30.
In the example of the image illustratcd in Fig. 5, the tellurium particles representing the-image former in area 30, preferably and advantageously in the form of needles, have a very narrow size distribution. This is a very favorable char~
acteristic of the imaging organo-tellurium materials of the present invention, since it permits the making of high quallty images of uniform properties. ~It permits also to produce a well-balanced gray scale. By varying the compositlon of the imaging organo-tellurium materials, by varyiny-the concentra-tion of the imaging organo-tellurium materlals in the glassy matrix material and/or by varying the proportion of the sensi-tizer and by adjusting the imaging and developing conditions, such as the intensity and duration of application of the ima-ging energy and the intensity and duration of the application of the developing energy, the tellurium particle sizes, notably the length of the tellurium needles constituting the imagq former, may be controlled. Depending on the intended use of the .
image, one will favor extremely small size needles. In certain cases, increasing the length of the tellurium needles will in-~:, .
cresse the relative density and contrast, but may reduce the " ' resolution potential of the system. In general, the greater the length of the tellurium needles, leaving everyt'hing else ;~ , .
' equal, the more pronounced will be the photographic gain and "` : :
' ' , ~ . . . .

.
. .

10~8149 :
- .the photographic speed of the system. The selection of particular imaging organo-tellurium materials which possess variab~e chemical or other reactivity enables the production of novel photographic systems which, with respect to the resolution, sensitivity to ambient light, photographic sensitivity, speed ;;~
of development and access to the image, fill various of the i needs for which photographic systems are presently used or may be beneficially used.
In another illustrative embodiment of the present invention, utilizing the imaging film of Example G in the structure shown in Fig. 1, an electronic flash gun is used to provide an about 1 millisecond flash of broad spectrum light. The layered A`~' structure is then placed for 3 to lS seconds onto a hotplate, at a temperature of about 130-140C, whereby almost instantly a sharp image appears which is an exact negative duplicate of the image represented by the imaging mask. The image has ex-cellent resolution and sharpness. When a sample is made from the "white" imaging compound of Example (1) and con~aining some acetophenone and flashed in the manner noted above, no change in the film can be observed by the naked eye. Upon heating, as described, an image of good contrast and definition appears.
. ~ , ,.
Although the imaging organo-tellurium material used in the preparation of the imaging film are commonly crystalline o; in character, the virgin film as laid down in a dry-to-the-touch film on the substrate, and prior to the initial imaging step, appears generally or usually to be non-crystalline so far . . .

.-; . . :

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.

10tj8149 . ~:
, j : - . -~` as has be~n det~rmined by X-ray diffraction testing. After the development step, the ~etallic tellurium, advantageously in needle form, appears although particle size and shape due to nucleation and perhaps other forces cause modifications, the - . . . . ~
exact nature and character of which have not yet been fully delineated. The size of the metallic tellurium needles appears to be affeçted by such considerations as the imaging film thickness, the chara~ter and viscosity of the matrix, the :~: ' .
presence and the amount of organic solvent in the film when subjected to imaging energy, and the temperature at which development is effected which also bears upon the color of the ' , . ~: . ' ~ -- flnal lmage. ~ ~
Depending on the desired result in the particular system used, the thickness of the layer 14 (Fig. 1) in the structure of the invention may ke varied in wide limits, as heretofore :. . . : .
noted. The layer containing the imaging organo-tellurium ma--. . O
terial may be as thin as lOOOA or less and as thick a~ lmm or -more. For producing transparencies or reflection copies, layer ;: .- . , ' - - . ' ' thicknesses of about 0.2~m to about 20,~m are generally most favorable. The most desirable thickness of the layer depends on such factors as the concentratlon of the imaging organo-- tellurium material in the matrix,~the nature of the image former, the maximum density desired, the differential in re-flection or transmissiveness desired, and on many other factors.
In each system one can readily determine the most favorable thickness of the layer by considering these factors. For cer-tain purposes such as recording information in data processing `~ . ' - :

~ --': . .
' . ' .. . ' " ~ I ' ' "' ., ' . : ' 8 1 ~9 equipment, the layers of the imaging material may be much thicker or thinner tha~ the above stated figures, The forma-- .
tion of nuclei and of the preferred image forming crystallites -~ is influenced to some degree by the thickness of the film.
. ~
Apparently, surface effects and interfacial effects must be considered in the nucleation reaction and in the reaction lead-..
ing to the small image forming-crystallites. In selecting the most favorable film thickness of the imaging layer, therefore, also these factors must be considered. ~ ~ ~
:
}0 Similar considerations apply to the selection of the con-:, centration of the imaging material in the matrix material.
.
Generally, it is desirable to use the imaging material in as :
- high a concentration as is possible. The functions served by the matrix material have been noted above and require no rei-teration. The matrix material itself, and the inclusion of .
plasticizers, if desired, tend to function as solvents for the :,`', . :. ' - imaging materials and to render the film, as deposited and ~ dried, amorphous in character. The compatibility of the ma-".~ . .
trix material and the imaging organo-tellurium materials appears to a~d to the sensitivity of a given system and pro~ides better ~. .
images or better contrast and higher density.
.
Another relevant consideration is the relationship of the -glass transition temperature of the matrix material and the temperature at which cleavage of the molecule of the imaging .
organo-tellurium material used in each instance occurs under ~ ~ the particular xeaction condition and in the particular sur-: ' ' ' ' ' ' ' .

.
. . .
.
. .
_ _ . . _ .. . . . .. . . . . ... , . . _ . . ., ~ .. . ... .. . ..... _ . .. . . ... . .. ..... ,. ... . . _ ._ , . j . . , _ 106814~
. ` .- .
roundings. If, for instance, the molecule of the imaging or-gano-tellurium material starts to decompose or cleave at a temperature much lower than that o- the film, secondary reac-- tions may take place locally which inactivate-all or part of the cleavage products of the imaging organo-tellurium material whlch, therefore, lowers the efficiency of the particular imaging system. In certain systems it may be-desirable that the cleavage of the imaging organo-tellurium material is inlti-ated at a lower temperature than the glass transition t'empera-ture of the matrix material, and, when the glass tr-ansition temperature is reached in the deveiopment step, reaction prod-ucts migrate to the nucleation sites, delivering the atoms of the metallic tellurium for the building up of the image-form-~ ~ . ... . .
ing tellurium needles. Hence, by careful correlation of these , factors, better imaging performance can be achieved.
... . .
With regard to the substrates, which have been mentibned above and of which certain illustrative examples have been given, it may be observed that the substrate may be any material capable of forming a film or plate, provided that it has a melting or softening point higher than the temperature utilized -for the development of the latent image, and provided it is sufficiently unreactive so as not to interfere with the imaging reaction. Suitable substrates are glass, mica, polyamides, polyesters, polystyrenes, hardened condensation polymers such as of the epoxy type, etc. Many heat resistant polymers are .
commercially avallable which fulfill these conditions in an excellent manner, and which, therefore, are excell~ntly suited : ` . :
: -.. .. . . - . . ~ ..

10~i81~9 as substrates in the im~yillg structure o~- the present invention.
~or most commercial applications of the imaging organo-tellur-ium materials it is desirable that the substrate be flexible so as to permit use in the form of continuous rolls in printers ~ ;
and in readers. If transparencies are to be produced in a particular imaging system, it is, of coursei desirable that the substrate be light transmissive. On the o*her hand, if copies are to produced which are to be detected by reflectlon viewing, it is preferred that a substrate be used which has a ~10 high reflectance such as heavily filled white or colored card-board and other similar structures.
In certain cases, if desired, the substrate may be omitted and layer 14 may be used as a self-supporting structure whlch is imaged and developed while, for in~stance, supported on a temporary supporting structure. In this case, the finished ~, .
image structure consists merely of a thin film of the amorphous - glassy matrix material containing incorporated therein the imaging organo-tellurium material and sensitizer, plus such additives or supplemental materials as may be used, and the - ~ .
~ image former precipitated therefrom and transformed therein.

While, as described above, the component ingredients of ~; the imaging composition, namely, the matrix material, the imag-ing organo-tellurium material and the sensitizer, plus such .
additional or supplemental materials as may be incorporated therewith to obtain particular special properties, are admixed and embodied in a single layer, or as a single layer on a , . ' .
.~ ` - ' .

' .

,' ~ -,: - . .

106~ 9 ~selected substrate, it is within the scope of the invention to - utilize a multi-layer system, more particularly a two-layer system. Thus, by way o~ illustration, one layer can include the sensitizer, ~or instance, 9,10-phenanthrenequinone carried or distributed in the matrix, for instance, a polyvinyl formal, and supported on a substrate, say a "MYLAR" sheet; and the other layer can include the imaging organo-tellurium material carried or distributed in the matrix, which may be the same or a different matrix but, desirably, is the same matrix, and said layer is, likewise, supported on a substrate, say, again a "MYLAR" sheet. Such additional or supplemental materials as may be utilized can be incorporated in whole or in part in either of said layers or distributed through both of said layers.
Exposure to imaging energy is then carried out of only the layer containing the sensitizer in which the latent ima8e is formed. The production of the developed or visible image can then be effected, for instance, by pressing the latent image layer against or onto the imaging organo-tellurium material -containing layer, in generally sandwich form, and then sub-iecting the assembly to heat, say at about 150C for, forinstance, of the order of about 15 seconds, the heat being applied from either or both sides through the "MYLAR" substrate or substrates. An image of generally neutral tone promptly appears. This type of procedure provides a favorable alinement simply and with no criticality requirements.
In certain cases, preheating of the virgin imaging film, prior to exposure to imaging energy, at a temperature in the :
~ -47-.. .. .

10~ 4~

.
range of 80-150C ~or a few or several scconds, enhances r~sis-- tance of the virgin i~aging film to moisture without adversely affecting thesensitivity of the film.
As noted previously, various forms of energy may be used as the imaging energy and as the development energy. This may include electromagnetic radlation, heat, electrons, elec-trical current, monochromatic light, etc. The preferred energy depends also on whether a negative working or a positive working system is employed. In the imaging step, actinic light or ' electromagnetic radiation is generally used for this step, for instance, light of a wave length of 450nm using a Bausch and Lomb monochromator and a 150 watt Xenon lamp. Radiant electro-magnetic radiation is usually best suited to produce an image by pro~ection or by the use of a mask and the like. It is also generally suited best for producing an image having a desired gray scale or tonal gradation. Which kind of electromagnetic radiation or other radiant energy and which wavelength is used .
in a particular~insta~ce depends on the task to be performed and on the particular sensitivity of the imaying organo-tellur-ium material empolyed. Various of such imaging materials, in the presence of a sensitizer, inherently present or separately added, are sensitive to actinic radiation including laser energy and the like. If a give~, selected imaging organo-tel-lurium material is per se insensitive to,~or does not have its optimum sensitivity at, a wave length of actinic light or e]ec-- ~ tromagnetic radlation, which lS to be used or available for imaging, selected sensitizers, as noted and indicated above, are added tp render the said imaging matcrial sensitive or to shift the sensitivity into the desired range. In this manner, -; . . .. _ , one can, for instance, use an imaging organo-tellurium material which has its maximum sensitivity in the U.V. range of wave-length to a sensitivity in the range of visible light or for X-rays, etc. Similar considerations apply with respect to the energy used in the development step. Most desirably and advantageously, heat is used for the development. This may be radiant heat such as infrared radiation or microwaves or hot air or heat by contact and convection from a heated body, or it may be heat from a heated wet developing bath. The use of heat for the development offers the advantage that heat may readily be controlled as to intensity and duration. Heat is also inexpensively available from inexpensive equipment.
However, if desired, any of the other energy forms may be used for bringing about development of the exposed imaging organo-tellurium material, provided it is susceptible to this form of energy.
In each of the imaging and development steps, a combin-:
ation of different forms of energy may be used. In this case it is preferred to employ a combination of the energy most effective for imaging and of the energy most effective for the development. The development heat may also be supplied by -; heat generated by the absorption of electromagnetic radiation as is the case with lasers. Incandescent lamps, infrared lamps, laser beams, electronic or bulb photoflash units, mercury quartz lamps, etc. can be used for the imaging. In ; some cases, similar, as well as, of course, other sources can be used for the development.

' , ' ' ~' ~ ~ -49-~068~9 The energy may be applied for different lengths of time depending on the intensity of the energy source used. With - high energy imaging sources, pulses of a microsecond or less to a few milliseconds or more are commonly sufficient to com-- plete the imaging. With lower intensity energy sources, longer .;
times as, for instance, a fraction of a second to several seconds or from 20 to 90 seconds, or more, can be used. De-pending on the intended use of the images and on whether or not insensitivity to ambient light is desired, one wili select one or the other imaging organo-tellurium materials and adapt the imaging time and the intensity and the kind of imaging energy to the requirements of the selected imaging organo-tellurium material.
The time of development depends also to a degree on the intensity of the development energy employed, though in this case usually a threshold energy exists which must be exceeded.
- This threshold is one of intensity - of temperature in the .
case of heat energy - and must be exceeded to effect develop-ment. With the observance of this precaution, development is completed in a second or a few seconds or longer, for instance, of the order of 15 to 20 seconds or, generally, ln the range of 5 seconds to 2 minutes, depending on the tempcrature utilized and on the nature of or the particulax imaging organo-tellur-ium material used. The thickness of the layer of said imaging --S O-- ' ' '. i ' :

., ~ ' ` ' ,, i - 1068149 material and thc thicknes~ of the substrate may also affect - the time required for development. However-, in all instances, .~ .
developm~nt is quite xapid so that the said imaging materials and the method of the invention provide reasonably rapid access to the finished stable image. Genera11y speaking, speed and contrast increase with'higher temperatures and longer ' - 'development times. ' ~ -:
Depending'on the composition of the imaging organo-tellur-ium material, for instance, lt may be desirable to effect the 10 ~ development at a predetermined temperature. As stated, the temperature of development should be adjusted to a level above the threshold, at which the reactions, leading to the formation , of the image former, to wit, the precipitation of the met'allic tellurium needles, take place. On the other hand, the temp-' erature should not be high enough to cause the thermally in-.~ .
duced nucleation and reaction in the areas which have not been subjected to the imaging energy. Usually, the range between these two temperature limits is rather wide, and the tempera- '' - ture can be readily adjusted to fall into the intermediate, useful range. If these precau~ions are observed, an image of ' high contrast with low nucleation in the background areas is . , .
obtained. In general, where heat development, and particularly . . .
' _ dry heat development, is employed, the development temperatures wlll commonly fall within the range of about 120-170C, it being understood that, generally, the lower the development temperature the longer will the heating time be-required for :, ~
.
.. . .
~ 51- - -'', . ' . ' . , ; ~ ~

~06~314~

producing the sc~ne optical density. Generally, also, there are, commonly, differe~ces iD shad~s of the final image de- - - -pending upon the development temperature employed. Thus, for instance, in the embodiment of Example A, a development temp-erature of about 130C produces a brownish image whereas a development temperature of 150-160C produces a blueish-black image, a situation which possibly may be due to differences in size of the tellurium needle crystallites. Again, generally speaking, the effect of appr~ciably increasing the concentra-tion of the imaging organo-tellurium material and the sensi-tizer is to enable lower development temperatures to be em-ployed where thermal development procedures are utilized.
In the thermal development step, depending upon the particular imaging organo-tellurium material employed but, for instance, in the case of such illustrative compounds as those o~ the ; ~ above Examples 1,2 and 3, volatiles are released, such as hydrochloric acid, during the initial stages of decomposltion - - of the imaging organo-tellurium materials, whlch may, and ~ appear to, have an accelerating or autocatalytic effect in the~
reduction reaction which ultimately results in the formation of tellurium needles and may play a role in such amplificatlon as occurs in the development step.
j - Wet development can be utilized with or without heat, and, ; where heat is utllized in conjunction with wet development, ;- such heat can be applied extraneously by a heat lamp such as an infrared lamp or the like, or the wet developing bath may ':

- - :

.. . .

. . . : . , ~ Ir 10t;81~9 be applied hot. Such wet development baths may be of various compositions, illustra,tive thereof belng baths consisting of a hydrogenated veget~ble oil or a silicone oii or such an oil - in admixture with minor proportiorsof DMF and/or a~reducing ~ -~
agent such as hydrofquinone or reducing sugars such as glucose or dextrose. The DMF functions as a swelling a~ent for the development of latent image fonmed from a film such as-that of Example J, and the effect appears to produce an increase in ~photographic speed with the realizati n of an appreciable gain .: . -, - ~
10factor, particularly where the sènsitiz~er, such as 9,10-phen- ~

anthrenequinone, is used in the higher ranges of concentration : . , -. . . .. .
;~ ~in the imaging film compositions.
-In any event, after initial exposure to imaging energy,~
the thus exposed or iatent imaged film can be developed immed-iately or, if desired, even after days or many weeks in stor-age in the dark or under other non-development storage condi-tions.
~ In certain cases, after the formation of the latent image `~ i by exposure to imaging energy, the layer or film, p-rior to.. , - , - -~ development, may be treated with an organic solvent or mixture of organic solvents, for instance, such as DM~ or mixtures of ,;. ,' : ~ . .
DMF and acetone, to wash out the unreacted sensitizer, while leaving the latent image essentlally unaffected. Then said ~ layer or film containing the latent image is then subjected to - ~ development energy to form the visible image. This procedure, ~ ~ in certain cases, appears to play a favorable role in regard to ~ , .
; ,. . .
. - , ~ . . ' ' ':

~0tj81~9 gain considerations.
The mechanisms ,of the reactions occurring in the practice of the present inventlon have not been entlrely elucidate~, but it appears that exposure of the compositions containing the imaging organo-telluri~n materials to imaging energy causes the organo-tellurium materials to undergo an electronic altera-tion to an excited state brought about by energy-transfer from the sensitizer and/or by direct excitation~ of the organo-tel-lurium molecule, with the formation of appreciable numbers of nucleation sites or points in the imaged areas and wit'h sub-stantially no or very few such sites or points in t'he unlmaged areas. It appears, further, that absorption of the imaging energy by the sensitizer to form the nucleation sites or points occurs initially on exposure of t'he imaging organo-tellurium material and sensitizer (whether the latter is inherently present by reason of the particular chemical structure of the . ..
imaging organo-tellurium material, or by the presence of a - decomposition produc~ having sensitive properties, or by the " :
- addition of a separate or extraneous sensitizer)'by a hydrogen abstraction mechanism from the polymeric matrix material or t'he ~' like. The latent image is apparently the result of a chemical ., .
modification or photochemical reduction of the sensitizer by . . .
the imaging energy in the presence of the imaging organo-tel-lurium material. It appears, although not yet fully ascer'ain- '~' ed, that the inltial latent image of nucleation sites or points which is formed is not defined, produced or delineated by metallic tellurium. It is possible t'hat the ini~ial latent image is m~de up of several, perhaps four ox more com-, :
, ' ' -, . . . - ~

~068i ~9 i ` - - - :
pounds, for instance, when 9,10-phenanthrenecluinone or ana-logous compounds are used as the sensitizer. In any event, in the subsequent devolopment step, ~ihich provides the needed energy to allow release of tellurium atoms from the organo-tellurium material at the nucleation sites or points, ~hich is especially deslrably effected thermally or by heat, the imaging organo-tellurium material, possibly in a metastable or unstable , - state, is converted by reaction mechanlsmsnot fully under-stood but which may inv~lve a reduction reaction by the hydro-gen which was abstracted by the sensitizer from the matrlx material or by the sensitizer car~ying said ab_~racted hydrogen, whereby to produce a relatively appreciable number of very small metallic tellurium particles, mainly or substantially entirely and advantageously in the form of needles, on the aforementioned nucleation sites or points. Electrons can also act as reducing agents and the materials themselves can also cause reducing.
- These metallic tellurium particles, advantageously in the form of needles, act as nuclei upon which further growth of -metallic tellurium takes place principally at the ends of said needles to produce longer needles which form and delineate the final developed image. The formation of the metalllc tellur}um needles by the reduction of the imaging organo-tellurium ma-: terial in the system, and under the conditions existent therein .
under the initial application o~ imaging energy followed by - development energy, apparently brlngs about further enhancement .
~ of the release of metallic tellurium-from the imaging organo--' -55-, . ~06814~ -tellurium material, ~hich forms a bountiful s~urce of tellurium, to effect, as noted above, further buildup of metallic tellur-ium on the initially formed metallic tellurium needles and~r principally at the ends thereof to increase the length t-hereof.
The length-wise growth of the tellurium need1es may be enhanced by field concentration at the sharp ends of the needles. The -optical density of the flnal visual image appears-to be the result of resonant scattering in addition to light absorption by the tellurium needles. Optical density after development increases initially linearly and then~logarithmically with exposure time. - -: The occurrence of the tellurium particles, which are crys-talline in character, is largely or substantially ubi~uitous throughout the matrix after development, but only in the illu-minated areas are the tellurium crystallites of such dimensions .
as to optimize the scattering of light which is responsible for - - the desired visual image. The formation of nuclei wl~ich occurs in the background or non-image areas is very substantially less ., . .::
~- ~ than in the image areas, and they are very widely spaced, and -this fact, coupled with the possibly somewhat different char-acter of such background nuclei, results in a relatively light background so that good contrast between the image area and the - background area is achieved. Furthermore, by careful handling of the imaging organo-tellurium materials from the beginning of their production to the imaging, and by effectively excluding carrier-formin~ energy of damaging lntensity prior to exposure to the imaging energy and up to the time of development, the numbcr of metallic tellurium particles in the non-image areas can stlll be further reduced.

~5~~
.' ~--: .

~068149 The foregoirlg discussion with respect to the matter of needle formation in the tellurium crystallltes may be somewhat elaborated ~u,pon by~a consider~tion of the following facts in relation, illustratively, to a film such as is produced pur-suant to Example J above. In the virgin film, that is,prior to exposure to imaging energy, under ex~mination using Trans-mission Electron Microscopy (TEM), black areas appear which indicate the presence of aggregates of the Bis(acetophenone) tellurium dichlorlde. The same film exposed for 100 seconds at 400nm and developed at 150C for 15 seconds~to an optical density of 1, sho~stellurium needles having a length generally~-' O - O
in the range of 1000 to 2500 A and a diameter of about 100 A
which are responsible for the visible image. On the other ~ hand, the same virgin or starting fllm not sub~ected to imag-- ing energy but subjected directly to heat at 150C for 15 seconds shows the presence of metallic tellurium but the pres-- ence of very Little or the essential absence of tellurium in the form of needles. ~inally, the same virgin or starting .. ~ , film exposed to imaging energy as described above in this para-graph but for a period of 70 hours at 450nm, but not developed, showed an abundance of tellurium needles.
Light or energy absorbed by the sensltizer is effective _for the formation of the latent image, and the exposed area becomes depleted in its content of the sensitizer in its orig-inal form in ~he film prior to exposure. Although, as has been indicated above, the latent image which is formed upon -~ 57-.. ,' ' ~ ' .

' . ,.. ; 10~8~
.
~posure to imaging energy lS apparently not fvrmcd or delin-eated by metallic tellurium, lt is possible that some metallic or crystalline tellurium, in very small amounts, may be present ~`
in the filM after exposure to imaging energy and prior to the development step.
Briefly and generally, the imaging layer including the matrix, the imaging organo-tellurium ma erlal and the sensitizer, as expressed above, is essentially an amorphous structure and it has one detectable characteristic, as for example, it being substantially light transmitting. When the imaging layer is subjected to imaging energy, nucleation sites or points are ; established in the imaged area of the imaging layer to provide a latent image therein. When the so imaged layer is subjected .
to development energy, such as heat, the imaging organo-tellurium material is reduced and deposits small crystalline metallic tellurium particles at said nucleation sites or points - in the latent image, advantageously in the form of small needles, forming small crystalline metallic tellurium nuclei upon which ; ~ further metallic tellurium is deposited by the further reduction of the imaging organo-tellurium material to provide larger crystalline metallic tellurium particles or needles in the imaged area. Thus, the initial structure of the imaging organo-tellurium material is changed to a~different structure in the imaged area, a crystalline metallic tellurium structure, having another detectable characteristic, for example, it being substantially non-light transmitting. In effect, therefore, the essentially amorphous structure of the imaging layer which is . , , ~

~ -58-- ~ ~
.;
' ' ' ' ' ' 1!~

106814g ~, ~ ` substantially light transmittin~ is transformed in the imaycd ;" . , --~ area to an essentially crystalline structure which is substan-tlally non-light transmitting-to form a visuall~ detectable : image. This is accomplished by the various materials, the : . ~ - , . .
relations and reactions between the materials and the transror-mation processes and mechanisms described herein.
, . , - , In summary, therefore, the mechanisms which come into play .,- . ~ : , : :
in the present invention involve the following considerations:
.,: - - . - , :, 1. A photosensitive organo-tellurium-material .
,~ 10 which is capa~le of excitation, under the influence of imaging energy, and in the - -,: . ~ - , presence of a sensitizer, to a reactive ,. . ~ , , .
state and optimumly with good efficiency.
2. The~ ~ * sihglet and/or the~r * triplet .
are the most reactive states, and prefer-ably are the lowest states of the sensi- - -, . . . .
- tizer. ~ . -; 3. The matrix contains readily easily ab-: ~ ~ stractable or extractable hydrogen atoms. -4. The excited state possesses sufficient energy and a sufficient time period to , permit abstracting hydrogen atoms from , ,~ the matrix by the sensitizer. - - ~ ~ -5. The organo-tellurium material is one which is reactive toward a metastable intermed-.; ~ :

~:
- . .
........................... . ,~
~ -58~-~, . -.~4 .
'' : ' , ~ ~ ' -. ' 10f~8149 iate ~o yield Te needles.
-. . . , .- -: .. :
~; Films made in accordance with this invention may have . . . ~ .
high photographic resolution, for instance, in various cases, ;~
of the order of 50~ to 600 line pairs/mm and good continuous tone with gamma close to unity. .
The shelf life of the latent image is, generally, good.
.. . .. . ~. .
-~ On unduly prolonged storage, however, of the order of several ' ' , ' : .' ~ . ': ' days or more, development tends to occur at materially lower temperatures than would otherwise be necessary to obtain effec-tive thermal development. Contact of the latent imaged films . . .: . . . ~ :
with various solvents, and dry, wet or low temperature storage '~

generally does not adversely affect the quality of the final . . . . :
image obtained after subse~ent thermal development of the . ' - . ' . :
; latent lmage.
; - ~ As to the developed image, its stability is, generally , ~ speaking, ~lso good, except, for instance, in the presence of oxidizing agents which cause fading of the image.
The foregoing discussion of the present invention sho~Js that it provides an excellent imaging system whlch may be wide-0 ly used for a variety of imaging tasks. The materials of the invention may be employed in~the camera, for proofing purposes -~
~ and for duplication of images, for making duplicate copies of microrecords ana microfiche, for recording output-information ... .
of a computer and for the output of other data storage and retrieval systems. The broad usefulness of the new imaging system of the invention is predicated on the quick and ready .

: , . -~ _59_ . . . ., ,, - .

:: : , , , ~ , : 10681~
- access to permanent copy of the information of the record or image. Different methods of readout can be used based upon differences in reflecti~ity, transparency, opaqueness, electric-al properties, the ability to hold electrical charges, etc.
The records and images are sharp and have good to excellent resolution. The organo-tellurium imagin~ materials used in ; the practice of the present invention can be varied from a low gamma to high gamma as may be needed and desired in each individual i~stance.
10In this respect, the new imaging system, generally speaking, has much of the versatility of the established silver halide system, which by choice of emulsions and development conditions also permits a wide variety of gammas.
However, as is readily apparent from the foregoing, the imaging system, as well as the development system, proper, of the present invention does not require wet treatments and, moreover, it provldes rapid access to the finished, stable image which is many times not the case with the silver halide images. This makes the new system, particularly in such instances, superior in numbers of respects to the established silver halide systems.
The various other imaging systems which are being used or have recently been proposed as not requiring a wet treatment usually have the disadvantage that they are predicated on the use of a single photosensitive material with little possibility of varying the character of the material such as varying the gamma of the image. They may, therefore, be suitable in one . ' ~ 60-', ' , ~", ,., . ~

10~81fl~ :
particular application but are not suitable in any other applications. The imaging organo-tellurium materials used in the lmaging system of ~he present invention are, generally speaking, inexpensive and may readily be applied by inexpensive methods so that a low cost imaging system is provided.
The present invention does not require vacuum deposition or sputtering of an elementary image former onto a substrate.
The imaging compositions may readily be applied in form of a solution e.g. by wipin~, spin deposition, application by a doctor knife, etc. The images produced by the practice of the present invention can be used as a prin~ master, e.g. when an image former is selected which has a capacity for acceptin~
and holding electrical charges dlfferently from the matrix material. In this case, the images can be produced, for instance, on a paper or cardboard substrate to provide an inexpensive, throwaway printing master. After a desired number of copies have been made from it, the print master is simply discarded.

.':
.. ~"
,:, ~
." ' ~''"""'.
-';. ',', ".:
:.' ' . ':
~ 61- ~

:

.

Claims (38)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A method of producing a record of retrievable inform-ation comprising:
providing a layer comprised of a non-complexing matrix including an imaging organo-tellurium material which inherently possesses sensitizer properties or is admixed with a separate sensitizer, in which tellurium is linked directly to at least one carbon atom of an organo radical of said organo-tellurium material or is complexed with an aromatic amine, said imaging organo-tellurium material being of one structure and having one detectable characteristic which is capable of undergoing a change in response to the application of energy to produce a material of different structure having another detectable characteristic, the step of applying imaging energy to certain portions of said layer to bring about in said certain portions of said layer the formation of a latent image, at which said imaging organo-tellurium material can be changed to said different structure having said other detectable characteristic.

2. The method of Claim 1, in which said imaging organo-tellurium material contains halogen linked directly to a tellurium atom, and in which an organo radical of said organo-tellurium material contains at least one carbonyl group.

3. The method of Claims 1 or 2, in which the halogen is chlorine.

4. The method of Claim 1, in which said imaging organo-tellurium material corresponds to the formula Rx-Te-Cly where R is an organo radical containing at least one carbonyl group, x is 1, 2 or 3, and the sum of x plus y is 4, and Te is linked directly to carbon in an organo radical.

5. The method of Claim 4 in which the imaging material is a compound of the formula

6. The method of Claim 1, in which said imaging organo-tellurium material is a tellurium tetrahalide adduct of an aromatic amine in which nitrogen attached directly or indirectly to the aromatic radical is substituted by alkyls each containing from 1 to 4 carbon atoms.

7. The method of Claim 6, in which the tellurium tetra-halide is TeCl4.

8. The method of Claim 6, in which said imaging material correspond to the formula ((CH3)2N C6H5)2TeCl4.

9. The method of Claim 1, in which said imaging organo-tellurium material is an adduct of 1 mole of tellurium tetrahalide with from 1 to 2 moles of an ethylenic or acetylenic hydrocarbon.

10. The method of Claim 9, in which the adduct is that of 1 mole of tellurium tetrachloride with 2 moles of an alkene or a cycloalkene.

11. The method of Claim 1, in which said layer contains a separate sensitizer and a polymeric matrix material, said polymeric matrix material serving as a carrier for said imaging organo-tellurium material and for said sensitizer and as a source of abstractable hydrogen whereby to form a latent image under the influence of said imaging energy.

12. The method of Claim 1, in which the imaging energy forms a developable latent image, and then developing said latent image to produce a visible image defined by crystalline tellurium advantageously at least mainly in the form of needles.

13. The method of Claim 11, in which the sensitizer is a polynuclear quinone.

14. The method of Claim 11, in which said imaging organo-tellurium material and the separate sensitizer are dissolved or dispersed in a polymeric matrix material which is solid at room temperature.

15. The method of Claim 14, in which said polymeric matrix material contains hydrogen which is abstractable therefrom by the sensitizer under the influence of imaging energy.

16. The method of Claim 15, wherein the polymeric matrix material is a polyvinyl formal.

17. The method of Claim 1, in which the layer is sensitive to visible light.

18. The method of Claim 1, in which the layer is sensitive to ultraviolet light.

19. The method of Claim 12, in which the imaging energy is actinic light and in which the development energy is heat.

20. The method of Claim 1, in which said layer contains a reducible sugar.

21. The method of Claim 20, in which the reducible sugar is at least one member of the group of dextrose, glucose, arabinose, erythrose, fructose, galactose, fucose, mannose and ribose.

22. A method for producing a record of retrievable in-formation comprising:
providing a layer including an imaging organo-tellurium material in which tellurium is linked directly to at least one carbon atom of an organo-tellurium material or is complexed with an aromatic amine, said imaging organo-tellurium material being of one structure and having one detectable characteristic which is capable of undergoing a change in response to the application of energy to produce a material of different structure having another detectable characteristic, said imaging organo-tellurium material being distributed in a non-complexing polymeric matrix material, providing a separate layer of a sensitizer which is distributed in a polymeric matrix material, subjecting the layer containing the sensitizer to imaging energy to form a latent image therein, placing said latent image layer in contact with the layer containing the imaging organo-tellurium material, and then subjecting the resulting contacting layers to development energy for changing said organo-tellurium material at said latent image to said different structure having said other characteristic to effect development of said latent image to form a visible image.

23. The method of Claim 22, in which the imaging organo-tellurium material is Bis(acetophenone) tellurium dichloride, and in which the sensitizer is 9,10-phenanthrenequinone.

24. An article for producing a record of retrievable information in the form of a dry-to-the-touch layer comprising an imaging layer including a matrix containing an imaging material and a sensitizer, said matrix comprising a non-complexing polymeric material which is solid at room temperature and which contains abstractable hydrogen, said sensitizer being capable of absorbing photons from actinic radiation and, under the influence of said actinic radiation, abstracting hydrogen from said polymeric material whereby to form a latent image, said imaging material comprising an imaging organo-tellurium material in which tellurium is linked directly to at least one carbon atom of an organo radical of said organo-tellurium material or is complexed with an aromatic amine, said imaging organo-tellurium material being of one structure and having one detectable characteristic and which is capable of undergoing a change in response to the application of energy to produce at the latent image a material of different structure having another detectable characteristic.

25. An article according to Claim 24, in which the sensitizer is a polynuclear quinone.

26. The article of Claims 24 or 25, in which said imaging organo-tellurium material contains halogen linked directly to a tellurium atom, and in which an organo radical of said organo-tellurium material contains at least one carbonyl group.

27. The article of Claims 24 or 25, in which said imaging organo-tellurium material corresponds to the formula Rx-Te-Cly where R is an organo radical containing at least one carbonyl group, x is 1, 2 or 3, and the sum of x plus y is 4, and Te is linked directly to carbon in an organo radical.

28. The article of Claims 24 or 25, in which said imaging material is a compound of the formula

29. The article of Claim 24 or 25, in which said imaging organo-tellurium material is a tellurium tetrahalide adduct of an aromatic amine in which nitrogen attached directly or indirectly to the aromatic radical is substituted by alkyls each containing from 1 to 4 carbon atoms.

30. The article of Claims 24 or 25, in which the matrix is a polyvinyl formal.

31. The article of Claims 24 or 25, which contains a small proportion of an organic solvent.

32. The article of Claim 24, containing up to 15% by weight, of a polyether compound having the property of enhancing the shelf life of said article.

33. The article of Claim 32, in which the polyether com-pound is a polyethylene derivative.

34. The article of Claim 24, in which the matrix is a polyvinyl formal, the imaging organo-tellurium material is Bis(acetophenone) tellurium dichloride, and the sensitizer is 9,10-phenanthrene quinone.

35. The article of Claim 34, which contains a small pro-portion of an organic solvent.

36. The article of Claim 35, in which the organic solvent comprises dimethylformamide.

37. The article of Claim 24, in which said layer contains a reducible sugar.

38. The article of Claim 37, in which the reducible sugar is at least one member of the group of dextrose, glucose, arabinose, erythrose, fructose, galactose, fucose, mannose and ribose.