DE2155905B2 - Process for the preparation of a cocrystalline pyrylium dye-polymer complex - Google Patents

Description

The invention relates to a process for the preparation of a cocrystalline complex of a pyrylium dye with an electrically insulating polymer which has an alkylidene diarylene radical in the repeating unit having

It is well known that photoconductive materials are used in electrophotographic reproduction processes To use recording materials that are exposed to an imagewise exposure to electromagnetic radiation provide a latent electrostatic charge image which develops according to various methods, d. H. can be made visible.

Photoconductive recording materials suitable for performing electrophotographic processes particularly suitable have a photoconductive layer composed of a resinous binder dispersed photoconductive insulating material. Electrophotographic recording materials can be produced by first of all with a layer of an electrically conductive material coated substrate a layer of a applies photoconductive mass or the photoconductive Ground directly on an electrically conductive carrier made of metal or another suitable, electrically applies conductive material.

It is also known that the properties of photoconductive layers, in particular the sensitivity and / or the spectral response can be improved by using the photoconductive Produces layers using light sensitizing additives, such as those from US Pat 32 50615, 3141770 and 29 87 395 are known. Such photosensitizing additives can be used to produce the photoconductive layers Coating compounds are incorporated. With the help of such additives it is possible to increase the sensitivity of a recording material to radiation of a certain wavelength or, if desired, to improve over a wide range of wavelengths. The mechanism of such sensitistening has not yet been clarified exactly

The desired electrophotographic properties of a recording material depend on the Purpose for which the recording material is intended. For example, the Copying documents the spectral electrophotographic response can be such that a The broadest possible color spectrum can be reproduced. When the response of the photoconductor does not meet these criteria, an attempt must be made to increase the spectral response by adding to improve a photosensitizing additive. Furthermore, various other Requirements placed on the properties of the photoconductive layer This is how the recording material should ζ. B. be able to absorb a high surface tension and should have a low dark decay demonstrate. It is also desired that the recording material has one in terms of electrical sensitivity or the characteristic curve measured high sensitivity, a low residual voltage after the Exposure and has high resistance to fatigue

The sensitization of photoconductive layers can be carried out in such a way that one in the Layers incorporates certain dyes The addition of conventional dyes to photoconductive layers however, has only limited overall improvement in electrophotographic properties led, d. i.e., there is still a need the sensitivity in the shoulder and sagging area as well as the playback properties during playback of large areas to improve and achieve rapid recovery.

A further improvement in the properties of electrophotographic Recording materials can be achieved by using recording materials with photoconductive layers in which aggregates or cocrystalline complexes of certain Polymers, e.g. B. with alkylidene diarylene radicals and dyes, e.g. B. Pyrylium dyes are generated, the have the property of photoconductors or sensitizers. Such recording materials are made of the US-PS 36 15 414 and 36 15 415 known In the process known from US-PS 36 15 414 the aggregates or cocrystalline complexes produced by first placing them on a layer support exposed layer to the action of solvent vapors. In the US-PS 36 15 415 known method is the coating composition used to produce the photoconductive layer for the purpose of generating cocrystalline complexes, first the action of shear forces exposed, eliminating the need to treat the photoconductive layer with solvent vapors.

From GB-PS 11 53 506 it is also known, photoconductive layers with cocrystalline complexes from certain polymers and dyes by dissolving the two components in a suitable one Solvent, applying the solution to a layer support, drying the layer and optionally Post-treatment of the layer with solvent vapors.

Finally, from GB-PS 11 91 097 there is a method known that it enables the sensitivity of the US-PS 36 15414 and 36 15 415 and GB-PS 11 53 506 known photoconductive layers to increase even further. This method consists in that one first produces photoconductive layers according to the known processes mentioned and these Layers then covered with a solution of a suitable dye. With this last one Process, a second coating stage is therefore required.

It is characteristic of the known processes mentioned that the photoconductive aggregates or cocrystalline complexes are made "in situ" in a binder that is suitable for the end use of the electrophotographic recording material produced therefrom is often undesirable

The object of the invention is to provide a process for the production of isolated cocrystalline complexes indicate where this is obtained in pure form and then in the most varied of photoconductive forms Coating compositions can be dispersed as additives.

It has been found that the problem can be achieved by using a pyrylium dye and subjecting an electrically insulating polymer to a certain treatment and the resulting cocrystalline complexes isolated

The invention relates to a process for the preparation of a cocrystalline complex of a Pyrylium dye with an electrically insulating polymer, which in the repeating unit a Has alkylidene diarylene radical, which is characterized by

draw is that one

a) the dye and the polymer in a solvent containing a halogenated hydrocarbon, in which their solubilities are practically the same, Iösi,

b) the solution of the dye and the polymer slowly with a halogen-free, non-polar, organic precipitation liquid in which the dye and the polymer are insoluble, combined to precipitate the crystalline dye-polymer complex and

c) separating the complex formed from the solvent and the precipitation liquid

Under a "cocrystalline complex" is one To understand crystalline compound, the molecules of the dye and the polymer in a cocrystallized State in a single crystal structure contains in a regular arrangement of the molecules in one three-dimensional grid.

The method of the invention enables the field of application of the cocrystalline complexes or Expand aggregates as it is no longer necessary to put the aggregates in situ in a special Produce binder system. With the method according to the invention one is free in the choice of desired binder system. In addition, the production of electrophotographic recording materials using the cocrystalline obtained by the process of the invention Complex work is made easier, since no further treatment of a layer applied to a carrier is possible more is required.

The cocrystalline complexes which can be prepared by the process of the invention can be used in a suitable Binder system are dispersed, which can contain any desired photoconductor. To this Purposes are the complexes of a solution of binder and photoconductor in a solvent, which has practically no dissolving effect on the complexes, added. The resulting mass is added processed into a mixture and using conventional coating methods on a carrier applied After drying, the layer obtained consists of a multi-phase layer, whose heterogeneous character can be seen when looking at them at 2500x magnification, although the Layer can appear optically clear to the naked eye without magnification. Of course you can too macroscopic heterogeneity may occur. The complexes containing the dye are expediently located or aggregates in the discontinuous phase, predominantly in a particle size range of about 0.01 to 25 microns. In the case in which the complexes prepared by the process according to the invention to sensitize a special photoconductor, such as. B. zinc oxide, can also be used there are other discontinuous phases which need not fall within the specified range

Starting from the complexes that can be produced according to the invention, photoconductive layers can also be used a polymeric carrier that forms an amorphous matrix or a continuous phase, which, in contrast to a solution containing a discrete discontinuous phase. The discontinuous phase exists from the cocrystalline complexes which are produced by the precipitation process according to the invention. If the aggregate crystals produced as described above in connection with an organic Photoconductors are used, the resulting photoconductive mass contains hn generally only two phases, since the photoconductor is usually connected to the continuous phase of the polymeric carrier (auxiliary) forms a solid solution. On the other hand, when a particulate photoconductor, such as. B. zinc oxide is used there can be three phases. In this case there is a continuous polymeric phase, a das

ίο discontinuous phase containing aggregate, such as discussed above, and a further discontinuous phase before arising from the particulate photoconductor consists. Of course, such multiphase compositions can also have further discontinuous phases contained by trapped impurities. Another key feature of those made as above heterogeneous compositions is that the wavelength of the radiation absorption maximum these compositions versus the wavelength of the radiation absorption maximum a Substantially homogeneous, solid solution produced from the corresponding constituents is considerable is shifted Such a shift in the absorption maximum in the formation of multiphase heterogeneous systems for the present invention is generally on the order of at least about 10 nm. When mixtures of dyes are used, one dye can be a shift of the absorption maximum in the longer-wave area and another dye a shift of the Cause absorption maximum in the shorter-wave area.

Sensitizing dyes are used to prepare the aggregate compositions according to the method of the invention and electrically insulating polymeric materials used Typical examples of sensitizing dyes, which are suitable for the preparation of the aggregate compositions are pyrylium dyes including the pyrylium, thiapyrylium and selenapyrylium dye salts. Examples of such Dyes are those of the general formula

Ζ ^Θ

so in which mean:

R ", R ⁶ , R ^c , R« * and R ^e each (a) a hydrogen atom, (b) an alkyl radical with preferably 1 to 15 carbon atoms, e.g. a methyl, ethyl, propyl, isopropyl , Butyl, tert-butyl, amyl, isoamyl, hexyl, octyl, nonyl and dodecyl radicals, (c) an alkoxy radical, for example methoxy, ethoxy, propoxy, butoxy, amyloxy -, hexoxy and octoxy radical, and (d) an optionally substituted aryl radical, for example a phenyl and 4-diphenyl radical, an alkylphenyl radical, for example a 4-ethylphenyl and 4-propylphenyl radical, an alkoxyphenyl radical, e.g. 4-ethoxyphenyl, 4-methoxyphenyl, 4-amyloxyphenyl, 2-hexoxyphenyl, 2-methoxyphenyl and 3,4-dimethoxyphenyl radical, a / I-hydroxyalkoxyphenyl radical, e.g. a 2-hydroxyethoxyphenyl and 3-hydroxyethoxyphenyl radical, a 4-hydroxyphenyl radical, a halophenyl radical,

ζ. B. a 2,4-dichlorophenyl, 3,4-dibromophenyl, 4-chlorophenyl and 3,4-dichlorophenyl radical, one Azidophenyl and nitrophenyl radicals, an aminophenyl radical, e.g. B. a 4-diethylaminophenyl and 4-dimethylaminophenyl radical, a naphthyl radical, a vinyl-substituted aryl radical, e.g. B. a Styryl, methoxystyryl, diethoxystyryl, dimethylaminostyryl, 1 -Butyl-4-p-dimethylaminophenyl-1,3-butadienyl- and / S-ethyl-4-dimethylaminostyryl radical,

X is a sulfur, oxygen or selenium atom and Ζ ^{θ is} an anionic radical, e.g. B. an anion, such as a perchlorate fluoroborate, iodide, chloride, bromide, sulfate, periodate and p-toluenesulfonate anion, in addition, the pair R ^a and R ⁴ and the pair R ^d and R ^c together for the Completion of an aryl ring fused to the pyrylium nucleus mean required atoms.

Connection no. Name of the connection

IO

r>

18 19 20

21 22 23

Connection no. Name of the connection

Typical representatives of such pyrylium dyes are given in Table I below.

Table I.

27

28 29 30

31 32

4- [4-bis (2-chloroethyl) aminophenyl] -2,6-diphenylthiapyrylium perchlorate 4- (4-dimethylaminophenyl) -2,6-diphenylthiapyrylium perchlorate

4- (4-dimethylaminophenyl) -2,6-di-

phenylthiapyrylium fluoroborate

4- (4-dimethylamino-2-methy! Phenyl) -

2,6-diphenylpyrylium perchlorate

4- [4-bis- (2-chloroethyl) aminophenyl] -

2- (4-methoxyphenyl) -6-phenyl-

thiapyrylium perchlorate

4- (4-dimethylaminophenyl) -2,6-diphenylthiapyrylium sulfate

4- (4-dimethylaminophenyl) -2,6-diphenylthiapyrylium p-toluenesulfonate

4- (4-dimethylaminophenyl) -2,6-diphenylpyrylium-p-toluenesulfonate

2- (2,4-dimethoxyphenyl) -4- (4-dim-

thylaminophenyl) benz (b) pyrylium-

perchlorate

2,6-bis (4-ethylphenyl) 4- (4-dimethyl-

aminophenyl) thiapyrylium perchlorate

4- (4-dimethylaminophenyl) -2-

(4-methoxyphenyl) -6-phenylthia-

pyrylium perchlorate

4- (4-dimethylaminophenyl) -2-

(4-ethoxyphenyl) -6-phenylthiapyry-

lium perchlorate

4- (4-dimethylaminophenyl) -2-

(4-methoxyphenyl) -6- (4-methyl-

phenyl) pyrylium perchlorate

4- (4-diphenylaminophenyl) -2,6-di-

phenylthiapyrylium perchlorate

2,4,6-triphenylpyrylium perchlorate

4- (4-methoxyphenyl) -2,6-diphenylpyrylium perchlorate

4- (2,4-dichlorophenyl) -2,6-diphonylpyrylium perchlorate

30th

Yy

b0

39 40

41 42 43 4- (3,4-dichlorophenyl) -2,6-diphenyl-

pyrylium perchlorate

2,6-bis (4-methoxyphenyl) -4-phenyl-

pyrylium perchlorate

6- (4-methoxyphenyl) -2,4-diphenyl-

pyrylium perchlorate

2- (3,4-dichlorophenyl) -4- (4-methoxyphenyl) -6-phenylpyrylium perchlorate

4- (4-Amyloxyphenyl) -2,6-bis (4-ethylphenyl) pyryl iumperchlorate 4- (4-Amyloxyphenyl) -2,6-bis (4-methoxyphenyl) -pyrylium perchlorate, 2,4,6-triphenylpyrylium fluoroborate

2,6-bis (4-ethylphenyl) -4- (4-methoxyphenyl) pyrylium perchlorate

2,6-bis (4-ethylphenyl) -4- (4-methoxyphenyO-pyrylium fluoroborate 6- (3,4-diethoxystyryl) -2,4-diphenylpyrylium perchlorate

6- (3,4-diethoxy-jS-amylstyryl) -2,4-diphenylpyrylium fluoroborate 6- (4-dimethylamino-j8-ethy-istyryl) -2.4 diphenylpyrylium fluoroborate

6- (1 -n-amyl-4-p-dimethylamino-

phenyl-1,3-butadienyl) -2,4-diphenyl-

pyrylium fluoroborate

6- (4-dimethylaminostyryl-2,4-diphe-

nylpyrylium fluoroborate

phenyl) vinylene] -2,4-diphenylpyrylium fluoroborate

33 40 34 55 6- (l-butyl-4-p-dimethylaminophenyl- 1,3-butadienyl) -2,4-diphenylpyrylium 45 35 fluoroborate 6- (4-dimethylaminostyryl) -2,4-di- phenylpyrylium perchlorate 36 6- [jS ^ ß-bis (4-dimethylaminophenyl) - vinylene] -2,4-diphenylpyrylium per- ^{5 (1} 37 chlorate 2,6-bis (4-dimethyIaminostyryl) -4- 38 phenylpyrylium perchlorate 6-GÖ-Methyl4-dimethy! Aminostyryl) - 2,4-diphenylpyrylium fluoroborate 6- [1 -ethyl-4- (4-dimethylaminophe- nyl) -1,3-butydienyl] -2,4-diphenyl- pyrylium fluoroborate

6-fj8, ^ - bis (4-dimethylaminophenyl) -

vinylene] -2,4-diphenylpyryliumfluoro-

borate

6- [l-methyl-4- (4-dimethylaminophe-

nyl) -l, 3-butydienyl] -2,4-diphenyl-

pyrylium fluoroborate

4- (4-dimethylaminophenyl) -2,6-di-

phenylpyryl jumper chlorate

2,6-bis (4-ethylphenyl) -4-phenylpyrylium perchlorate

2,6-bis (4-ethylphenyl-4-methoxyphenylthiapyrylium fluoroborate

21 55 9 r: 905 10 Invention particularly suitable dye J continuation Name of the connection IO Name of the connection Connection no, Connection no. 2,4,6-triphenylthiapyrylium 44 perchlorate
4- (4-methoxyphenyl) -2,6-diphenyl-
thiapyrylium perchlorate 2,6-diphenyl-4- (4-methoxyphenyl) - 45 6- (4-methoxyphenyl) -2,4-diphenyl- 15th 72 thiapyrylium perchlorate 46 thiapyrylium perchlorate 2,6-diphenyl-4- (4-methoxyphenyl) -
thiapyrylium fluoroborate 2,6-bis (4-methoxyphenyl) -4-phenyl- 73 2,6-bis (4-ethylphenyl) -4- (4-n-amyl- 47 thiapyrylium perchlorate 74 oxyphenyl) thiapyrylium perchlorate 4- (2,4-dichlorophenyl) -2,6-diphenyl- 20th
25th 48 thiapyrylium perchlorate 2,6-bis (4-methoxyphenyl) -4- (4-n- 2,4,6-tri (4-methoxyphenyl) thiapyry- 75 amyloxyphenyl) thiapyrylium per- 49 lium perchlorate i0 chlorate 2,6-bis (4-ethylphenyl) -4-phenyI-
thiapyrylium perehlorate
4- {4-amyloxyphenyl) -2,6-bis (4-ethyl-
phenyl) thiapyrylium perchlorate
6- (4-dimethylarninostyryl) -2,4-di-
phenylthiapyrylium perchlorate
2,4,6-triphenylthiapyrylium fluoroborate 2,4,6-tris (4-methoxyphenyl) thiapyry- 50
51
52
53 2,4,6-triphenylthiapyrylium sulfate 76 lium fluoroborate 54 2,4-diphenyl-6- (3,4-diethoxystyryl) -
pyrylium perchlorate
4- (4-dimethylaminophenyl) -2-phenyl-
benz (b) selenapyrylium perchlorate
2- (2,4-dimethoxyphenyl) -4- (4-di-
methylaminophenyl) benz (b) selena-
pyrylium perchlorate 4- (4-methoxyphenyl) -2,6-diphenyl- 77
78
79 4- (4-dimethylaminophenyl) -2,6-di- 55 thiapyrylium fluoroborate S ^r i 80 phenylselenapyrylium perchlorate 2,4,6-triphenylthiapyrylium chloride 4- (4-dimethylaminophenyl) -2- 56 81 (4-ethoxyphenyl) -6-phenylselenapyry- 2- (4-amyloxyphenyl) -4,6-diphenyl- lium perchlorate 57 thiapyrylium fluoroborate 40 4- [4-bis (2-chloroethyl) aminophenyl] - 4- (4-amyloxyphenyl) -2,6-bis (4-meth- 82 2,6-diphenylselenapyrylium perchlorate 58 oxyphenyl) thiapyrylium perchlorate 4- (4-dimethylaminophenyl) -2,6-bis- 2,6-bis (4-ethylphenyl) -4- (4-methoxy- 83 (4-ethylphenyl) -selenapyryliumper- 59 phenyl) thiapyrylium perchlorate chlorate 4-anisyl-2,6-bis (4-n-amyloxyphenyl) - 4 ^r i 4- (4-dimethylamino-2-methylphenyl) - 60 thiapyrylium chloride 84 2,6-diphenylselenapyrylium perchlorate 2 - [/?, /? - bis (4-dimethylaminophenyl) - 3- (4-dimethylaminophenyl) naphtho- 61 vinylene] -4,6-diphenylthiapyrylium- 85 (2,1 -b) selenapyrylium perchlorate perchlorate ¹ st 4- (4-dimethylaminostyryl) -2- {4-meth- 6-08-ethyl-4-diniethylaminostyryl) - 86 oxyphenyl) benz (b) selenapyrylium- 62 2,4-diphenylthiapyrylium perchlorate perchlorate 2- {3 ₍ 4-diethoxystyryl) -4,6-diphenyl- 2,6-di (4-diethylaminophenyl) -4-phenyl- 63 thiapyrylium perchlorate 87 selenapyrylium perchlorate 2,4,6-trianisylthiapyrylium perchlorate Yi 4- (4-dimethylaminophenyl) -2- (4- 64 88 ethoxyphenyl) -6-phenylthiapyrylium- o-ethyl ^^ - diphenylpyryliumfluor- fluoroborate 65 borate b0 4-benzylamino-2-phenylbenz (b) pyry- 89 lium perchlorate 2,6-bis (4-ethylphenyl) ~ 4- (4-methoxy-
phenyl) thiapyrylium chloride 4-anilino-2- (4-methoxyphenyD- 66 2,6-bis (4-amyloxyphenyl) -4- (4-> meth- 90 naphto (l, 2-b) pyrylium perchlorate 68 oxyphenyl) thiapyrylium perchlorate h5 4- (N-Butylamino) -2-phenylbenz (b) -
thiapyrylium perchlorate 91 4- (N-butylamino) -2- (p-methoxyphe- 6- (3,4-diithoxy-.0-ethylstyryl) -2,4- 92 nyl) benz (b) pyrylium perchlorate 69 diphenylpyrylium fluoroborate 4- (4-dimethylaminophenyl) -2- (4- 6- (4-methoxy-8-ethylstyryl) -2,4-di-
phenylpyrylium fluoroborate 93 iithoxyphenyl) -6-phenylthiapyrylium- 70 2- (4-ethylphenyl) -4,6-diphenylthia- (luorborate and 71 pyryu perchlorate 4- (4-dimethylaminophenyl) -2,6-di-
phenylthiapyryliumhexaΠuoφhosphat 94 For the production of the units according to the Procedure of

fe are the pyrylium dye salts of the general formula

where mean:

Ri and R ₂ each have an optionally substituted phenyl radical with at least one substituent from the group consisting of the alkyl radicals with 1 to 6 carbon atoms and the alkoxy radicals with 1 to 6 carbon atoms,

R3 is an alkylamino-substituted phenyl radical

with 1 to 6 carbon atoms in the alkyl radical and z. B. a dialkylamino or haloalkylamino substituted Phenyl radical,

X is an oxygen or sulfur atom and

wherein

Ζ ^{Θ has} the meanings given above.

As polymers for the production of the isolated aggregate compositions by the process A wide variety of substances are suitable for the invention. It has proven to be particularly advantageous if a compound is used as the polymer which has a radical of the formula in the repeating unit having:

R ₄ R ₇
C.

R ₅

Il -o — c — o-

and

where mean:

. R4 and R5 individually each have a hydrogen atom, an optionally substituted alkyl radical with 1 to 10 carbon atoms, e.g. methyl, ethyl, propyl, isopropyl, butyl, tert-butyl, pentyl, hexyl, heptyl, Octyl, nonyl, decyl or trifluoromethyl radical, or an optionally substituted aryl radical, e.g. B. a phenyl and naphthyl radical, which can contain a halogen atom or alkyl radicals with 1 to 5 carbon atoms as substitutes or together to complete a cyclic hydrocarbon radical including a cycloalkane radical, such as. B. a cyclohexyl radical or a polycycloalkane radical, e.g. B. a norbornyl radical, required number of carbon atoms, the total number of carbon atoms in R «and R _{5 is} up to 19,

R ₆ and R ₇ each represent a hydrogen atom, an alkyl radical having 1 to 5 carbon atoms or a halogen atom, e.g. B. a chlorine, bromine or iodine atom, and

R _{8 is} a divalent radical of one of the following

Formulas:

Il —O — c — o—

-CO-CH ₂ -O CH ₃

Il I

- C - O - CH - O

Il

-CH ₂ -OCOO

Il —O — p — o—

Preferred in the process of the invention, the polymers used are the hydrophobic carbonate polymers, which have the following recurring unit:

R ₄ O

I Il

—R — C —R —O — C — O-

in the

R each represents a phenylene radical or a

halogen-substituted or alkyl-substituted phenylene radical means and

R4 and R _{5 have} the meanings given above.

Such compositions are described, for example, in US Pat. Nos. 3,028,365 and 3,317,466.

Polycarbonates which contain an alkylidene diarylene radical in the repeating unit which, for. B. with Bisphenol A are produced as well as polymeric ester interchange products between diphenyl carbonate and 2,2-bis- (4-hydroxyphenyl) propane (= bisphenol A) are useful for carrying out the process of the invention Particularly suitable. Such compositions are, for example, in US Patents 29 99 750, 30 38 874, 30 38 879, 30 38 880, 31 06 544, 31 06 545 and 31 06 546. It can be of the most varied film-forming polycarbonate resins can be used, with completely satisfactory results being obtained are, if polymeric commercial products are used, which by an inherent viscosity of about 0.5 to about 1.8 are characterized.

The following are examples of polymers which are used for carrying out the process of Invention are particularly suitable:

ί3

Table II Name of the polymer Polymer no. Poly (4,4'-isopropylidenediphenylene- 1 co-l, 4-cyclohexyldimethyl carbonate) Poly (3,3'-ethylenedioxyphenylenethio- 2 carbonate) Poly (4,4'-isopropylidenediphenylene 3 carbonate-co-terephthalate) Poly (4,4'-isopropylidenediphenylene- 4th carbonate) Poly (4,4'-isopropylidenediphenylenethio 5 carbonate) Poly (2,2-butane-bis-4-phenylene- 6th carbonate) Poly (4,4'-isopropylidenediphenylene- 7th carbonate block ethylene oxide) Poly (4,4'-isopropylidenediphenylene 8th carbonate-block-tetramethylene oxide) Poly [4,4'-isopropylidene-bis (2-methyl- 9 phenylene) carbonate] Poly (4,4'-isopropylidenediphenylene-co- 10 1,4-phenylene carbonate) Poly (4,4'-isopropylidenediphenylene- 11 co-1,3-phenylene carbonate) Poly (4,4'-isopropylidenediphenylene- 12th co-4,4'-diphenylene carbonate) Poly (4,4'-isopropylidenediphenylene 13th co-4,4'-oxydiphenylene carbonate) Poly (4,4'-isopropylidenediphenylene 14th co - ^ '- carbonyldiphenylene carbonate) Poly (4,4'-isopropylidenediphenylene 15th co-4,4'-ethylenediphenylene carbonate) Poly [4,4'-methylene-bis (2-methylphe- 16 lenjcarbonate] Poly [I, l- (p-bromophenylethane) bis (4- 17th phenylene) carbonate] Poly [4,4'-isopropylidenediphenylene 18th co-sulfonyl bis (4-phenylene) carbonate] Poly [I, l-cyclohexanebis (4-phenylene) - 19th carbonate] Poly [4,4'-isopropylidene-bis (2-chloro- 20th phenylene) carbonate] Poly (hexafiuorisopropylidene-di-4- 21 phenylene carbonate) Poly (4,4'-isopropylidenediphenylene- 22nd 4,4'-isopropylidenedibenzoate) Poly (4,4'-isopropylidenedibenzyl- 23 4,4'-isopropylidenedibenzoate) Poly [2,2- (3-methylbutane) bis-4-pheny- 24 lencarbonate] Poly [2,2- (3,3-dimethylbutane) bis- 25th 4-phenylene carbonate] Poly) l, l- [l- (l-naphthyl)] bis- 26th 4-phenylene carbonate Poly [2,2- (4-methylpentane) bis- 27 4-phenylene carbonate] Poly [4,4 '- (2-norbornylidene) dipheny- 28 lencarbonate]

Polymer no. Name of the polymer

Poly [4,4 '- (hexahydro-4,7-methano-

indan-5-ylidene) diphenylene carbonate]

and

Poly (4,4'-isopropylidenediphenylene carbonate-block-oxytetramethylene)

The aggregate crystals produced by the process of the invention can easily be used for improving the sensitivity and for expanding the spectral sensitivity range of various organic photoconductors and inorganic photoconductors including the n- and p-type photoconductors. A typical example of an inorganic photoconductor is zinc oxide. The aggregate crystals can be used together with many organic and organometallic photoconductive substances which have little or practically no permanent photoconductivity. Representative representatives of organometallic compounds are the organic derivatives of metals from groups IHa ₁ IVa and Va of the Periodic Table of the Elements, for example those which have at least one aminoaryl group on the metal atom. Examples of organometallic compounds are the triphenyl-p-dialkylaminophenyl derivatives of silicon, germanium, tin and lead, the tri-p-dialkylaminophenyl derivatives of arsenic, antimony, phosphorus, bismuth, boron, aluminum, gallium, thallium and indium. Suitable photoconductors

Is of this type are described, for example, in British patent specification 1211 595 and in Belgian patent specification 735334.

A particularly suitable class of organic photoconductors are those hereinafter referred to as "organic" Amine photoconductor «called photoconductor. These organic photoconductors have a structural feature in common at least one amino group. Examples of suitable organic photoconductors, which according to the Invention that can be spectrally sensitized are arylamine compounds such as (1) diarylamines, e.g. B. Diphenylamine, dinaphthylamine, N, N'-diphenylbenzidine, N-phenyl-1-naphthylamine, N-phenyl-2-naphthylamine, N, N'-diphenyl-p-phenylenediamine, 2-carboxy-5-chloro-4'-methoxydiphenylamine, p-anilinophenol, N, N'-di-2-naphthyl-p-phenylenediamine, as described in US Pat. No. 3,240,597, and (2) triarylamines, such as (a) non-polymeric triarylamines, e.g. B. triphenylamine, Ν, Ν, Ν ', Ν'-tetraphenyl-m-phenylenediamine, 4-acetyltriphenylamine, 4-hexanoyltriphenylamine, 4-lauroyltriphenylamine, 4-hexyltriphenylamine, 4-dodecyltriphenylamine, 4,4'-bis (diphenylamino) benzil, 4,4'-bis (diphenylamino) benzophenone, and (b) polymeric triarylamines, z. B. Poly- [N-4 "- (N, N ', N'-triphenylbenzidine) l polyadipyltriphenylamine, Polysebacyl triphenylamine, polydecamethylene triphenylamine, poly-N- (4-vinylphenyl) diphenylamine and poly-N- (vinylphenyl) - «,« '- dinaphthylamine. Other suitable photoconductors are anine type for example in US Pat. No. 3,180,730.

b5 Suitable photoconductive substances which, according to the Invention can be sensitized, are described, for example, in US Patent 32 65 496, and these include, for example, those of the following

general formula

R -

N-T--

where mean:

T is a condensed or linear, mononuclear or polynuclear, divalent, aromatic radical, ζ. B. a phenyl, naphthyl, biphenyl and binaphthyl radical, or a substituted, divalent, aromatic radical of these two types, which can be used as substituents e.g. B. an acyl group of 1 to about 6 Carbon atoms, ζ. B. an acetyl, propionyl or butyryl group, an alkyl group of 1 to about 6 carbon atoms, ζ. Β. a methyl, ethyl, propyl or butyl group, an alkoxy group with 1 up to about 6 carbon atoms, ζ. B. a methoxy, ethoxy, propoxy or pentoxy group or a May have nitro group,

M is a condensed or linear, mononuclear or polynuclear monovalent aromatic Rest, ζ. B. a phenyl, naphthyl and biphenyl radical, or a substituted monovalent aromatic Rest, which is used as a substituent z. B. an acyl group having 1 to about 6 carbon atoms, ζ. Β. an acetyl, propionyl or butyryl group, an alkyl group with 1 to about 6 carbon atoms, ζ. B. a methyl, ethyl, propyl or butyl group, an alkoxy group with 1 to about 6 carbon atoms, ζ. B. may have a methoxy, propoxy or pentoxy group, or a nitro group,

Q represents a hydrogen atom, a halogen atom or an aromatic amino radical, e.g. B. such the Formula MNH-,

b is an integer from 1 to about 12 and

R is a hydrogen atom, a condensed or linear, mononuclear or polynuclear aromatic Rest, ζ. Β. a phenyl, naphthyl and biphenyl radical, a substituted aromatic radical, which can contain an alkyl, alkoxy, acyl or nitro group as a substituent, or a poly (4'-vinylphenyl) radical, which is bonded to the nitrogen atom via a carbon atom of the phenyl group

Polyarylalkane photoconductors are particularly suitable for practicing the invention. Such photoconductors are for example in US Patents 74,000 and 35 42 544 and in the French Patent 13 83 461 described. These photoconductors include, for example, the leuco bases of diaryl or Triarylmethane dye salts, the 1,1,1-triarylalkanes, in in which the alkane radical has at least two carbon atoms and the tetraarylmethanes in which at least one of the aryl groups associated with the alkane and methane radicals of the latter two classes of photoconductors which are not leuco bases are connected, is substituted with an amino group.

Preferred polyarylalkane photoconductors are those of the formula:

J — CE
G

where mean:

D ₁ E

and G each represents an aryl radical and

_r J is a hydrogen atom, an alkyl radical or

an aryl radical, where at least one of the radicals D, E and G has an amino substituent having.

The ίο aryl groups connected to the central carbon are preferably phenyl groups, although naphthyl groups can also be used. These aryl groups can have substituents, such as alkyl and alkoxy groups with preferably 1 to 8 carbon atoms, hydroxyl groups and halogen atoms contained in the o-, m- or p-positions, an o-substituted phenyl group being preferred The aryl groups can also be linked to one another or cyclized to form, for example, one Fluorene residue. The amino substituent can be represented by the formula:

- N

in which L is in each case an alkyl radical with preferably 1 to 8 carbon atoms, a hydrogen atom, an aryl radical means or in which both radicals L together are those for the formation of a heterocyclic amino group mil preferably 5 to 6 ring atoms, e.g. B. a morpholino, piperidino and tetrahydropyrrole group Atoms mean. At least one of the radicals D, E and G is preferably a p-dialkylaminophenyl group. When J is an alkyl group, such alkyl group generally has 1 to 7 Carbon atoms.

Representative representatives for suitable polyarylalkane photoconductors are given in Table II below:

Table III Name of the connection Connection no. 4,4'-benzylidene-bis (N, N-diethyl- 1 m-toluidine) ■ ^ "- Diamino ^ -dimethylamino- 2 2 ', 2 "-dimethyltriphenylmethane ^ "- BisidiäthylaminoJ ^ o-dichloro- 3 2 ', 2 "-dimethyltriphenylmethane 4 \ 4 "-bis (diethylamino) -2 ', 2" -dimethyl 4th diphenylnaphthylmethane 2 \ 2 "-Dimethyl-4,4 ', 4" -tris (dimethyl- 5 amino) triphenylmethane

4 ', 4 "-bis (diethylamino) -4-dimethyl-

amino-2 ', 2 "-dimethyltriphenylmethar

4 ', 4 "-bis (diethylamino) -2-chloro-

2 ', 2 "-dimethyl-4-dimethylaminotri-

phenylmethane

4 ', 4 "-bis (diethylamino) -4-dimethyl-

amino-2,2 ', 2 "-trimethyltriphenyl-

methane

4 ', 4 "-bis (dimethylamino) -2-chloro-2', 2" -dimethy! Tp-phenylmethane

809 540/1

continuation

Connection no. Name of the connection

4 ', 4 "-bis (üimethylamino) -2', 2" -di-

methyl-4-methoxy triphenyl methane

Bis (4-diethylamino) -l, l, l-triphenyl-

ethane

Bis (4-diethylamino) tetraphenylmethane '

4 \ 4 "-bis (benzylethylamino) -2 \ 2" -di

methyl triphenyl methane

4 ', 4 "-bis (diethylamino) -2', 2" -di-

ethoxytriphenylmethane

4,4'-bis (dimethylamino) -l, l, l-tri-

phenylethane

l- (4-N, N-dimethylaminophenyl) -1.1 -

diphenylethane

4-dimethylaminotetraphenylmethane

and

4-diethylaminotetraphenylmethane

25th

CH = CH-CR ₁

20th

Another class of photoconductors that works for the The 4-diarylamino-substituted chalcones are suitable for carrying out the process of the invention. Typical Compounds of this type are the non-polymeric ketones with low molecular weight of the general jo a formula:

35

in the

Ri and R2 each optionally substituted phenyl radicals and in particular those in which R2 is a phenyl radical of the formula means:

45

in the

R3 and R4 each have aryl radicals, aliphatic radicals with 1 to 12 carbon atoms, e.g. B. alkyl radicals with preferably 1 to 4 carbon atoms, or represent hydrogen atoms.

Particularly advantageous results are obtained when Ri is an optionally substituted phenyl radical and R2 is a diphenylaminophenyl, dimethylaminophenyl or phenyl radical.

Other photoconductors used in connection with the aggregate compositions made by the process of the invention can be used are e.g. B. Rhodamine B, malachite green, crystal violet, phenosafranine, Cadmium sulfide, cadmium selenide, parachloranil (tetrachlor-p-benzoquinone), benzil, trinitrofluorenone and Tetranitrof luorenone.

Useful in making photoconductive compositions in accordance with the present invention Results obtained when an organic or

¹ JO

b5 organometallic photoconductor is present in an amount of at least about 0.5% by weight of the total solids added to the coating solvent. The upper limit of the amount of photoconductor present can be varied widely, with up to 99% by weight of total solids being suitable . A preferred weight range for the photoconductor is from about 10 to about 80 percent by weight. If the aggregate compositions obtained by the process of the invention are to be used alone as the photoconductive substance, then of course no photoconductor needs to be added. If desired, polymeric photoconductors, e.g. B. poly (N-vinyl carbazole) or halogenated poly (N-vinyl carbazole) can be used.

In the method of the invention, one of the pyrylium dyes defined above is used together with one hydrophobic polymer dissolved in an organic solvent system containing a halogenated Contains hydrocarbons. Examples of suitable halogenated hydrocarbons are all those Solvents that have a significant solvent effect on both the dye and the polymer to have.

Particularly suitable solvents are, for. B. chlorinated short-chain alkanes with 1 to about 4 carbon atoms, z. B. dichloromethane, chloroform, carbon tetrachloride, 1,1-dichloroethane, 1,2-dichloroethane and 1,1,2-trichloroethane and chlorinated aromatic hydrocarbons, z. B. chlorobenzene, bromobenzene and 1,2-dichlorobenzene. The conditions under which the Dissolution of the dye carried out are not particularly critical, provided that the temperature no factor for adjusting the relative solubility of the dye and the polymer in the following Precipitation level is. Taking this factor into account, the temperature can be any Temperature below the boiling point of the solvent and below the decomposition temperature of a of the components. In the same way, sufficient stirring can be carried out to keep the solution within a reasonable time to promote. The organic solvent system in which the dye and the Polymer are dissolved, other solvents besides one of the abovementioned solvents can be used contain. The reason for this can be seen by considering the following steps in the process of the invention considered

After the dye and the polymer in the containing a halogenated hydrocarbon Solvent system have been dissolved, a precipitation liquid becomes slow with the solvent system combined to a precipitation of the dissolved components of the solution on a predetermined Way to effect. This precipitation liquid is characterized by the fact that it is a halogen-free, is non-polar liquid in which neither the dye nor the polymer is soluble. It can be a liquid with a low dielectric constant, e.g. B. below about 5.0 act. Suitable Liquids are e.g. B. Alkanes having about 6 to about 12 carbon atoms that are straight or branched chain can be, such as B. hexane, octane, decane, dodecane and 2,2,4-trimethylpentane and ligroin and mixtures of that.

The precipitation conditions are such that in the presence of the organic solvent system and the precipitation

treatment fluid is a cocrystalline complex of the dye is formed with the polymer. To ensure that a cocrystalline complex des Dye with the polymer and not just another crystalline form of the dye or a Precipitated form of the polymer is formed alone, the precipitation conditions must be carefully controlled will. The dye and the polymer are first good for both compounds Solvent dissolved, e.g. B. in dichloromethane. Then it will be to the solution a precipitation liquid, e.g. B. hexane, added. This precipitation liquid is a non-solvent for both the polymer and the dye. The precipitation will examined to determine if this is the dye or the polymer alone; This can be done visually or by customary analytical methods and is not the subject of the invention. if it is found that z. B. the dye has precipitated, a solvent, for example Toluene, which is a better solvent for the dye than for the polymer Alternatively, the amount of dye originally present in the solution can be compared to the amount of polymer be reduced. According to a further alternative, the temperature of the solution in the Be changed in such a way that the solubility of the dye increases at a greater rate than that of the polymer. Conversely, if it is found that the polymer has precipitated, so the polymer concentration can be reduced, a preferred solvent for the polymer can be added or the temperature can be changed in such a way that the solubility of the polymer opposite that of the dye increases. The preferred method is to find the relative concentrations of the dye and the polymer to match each other, so that they are about the same time and with precipitate at the same speed in the form of the cocrystalline complex. To provide a general guideline for to get the relative amounts of dye and polymer used to begin with should be, the respective solubility can be determined at the beginning, and the concentration of both Compounds is chosen so that it is approximately directly proportional to the solubility. For example, if the dye is less soluble, its concentration in the solvent system is decreased. if it has been found that the precipitate is the cocrystalline complex, the Precipitation liquid added in sufficient amount to complete the precipitation of the product. As indicated above, the aggregate material described in US Pat. No. 3,615,414 due to the occurrence of a spectral absorption shift compared to the absorption spectrum of the dye alone can be identified. The shift appears as a change in the position of the spectral absorption maximum compared to that of the dye in the order of magnitude of at least about 10 nm.

It has already been pointed out that the precipitation liquid with the solvent system is slow is combined to precipitate the desired cocrystalline complex. A preferred method to combine the two liquid media is to use one of the liquids at a speed to drop from about 1 to 3 drops per second to the other. Preferably this will be the dye and the polymer-containing solvent system of the precipitation liquid was added dropwise, although the reverse Trap the same product but at a much slower rate.

The ratio of dye polymer in that containing a halogenated hydrocarbon Solvent system can be varied over a limited range in which one still has one

ίο reliable precipitation of the cocrystalline complex when combined with the precipitation liquid. The proportions of dye to polymer are in generally within the range from about 1:10 to about 2: 1, preferably from 1: 7 to 1: 1, where reliable precipitation of the complex is generally obtained within these ranges. Accordingly the ratio of precipitation liquid to solvent can be relatively broad Range can be varied, values within the range from about 50: 1 to about 1: 1 being preferred and Values from about 20: 1 to about 2.5: 1 especially are preferred.

After the aggregate material is manufactured, it is removed from the liquid medium in which it is manufactured has been separated. The separation can be carried out in the known manner of separating a liquid from a suspended solid, e.g. B. by filtering, centrifuging or decanting. A preferred one Procedure consists in the contents of the jar

jo into a Büchner funnel fitted with a piece of filter paper. After removing the Using, for example, a weak vacuum, the crystals will be deposited on the liquid Paper withheld. The remaining liquid is then removed by drying the filter paper and its Contents at a suitable temperature of about 40 to about 120 ° C within a period of a few Minutes to about an hour, depending on the temperature used, away from the crystals.

-to after the crystals from the solvent system and the precipitation liquid have been separated, they can be in a suitable polymeric carrier or Binder system, as indicated above, are dispersed. The binder is in a suitable Solvent is dissolved and the aggregate material or crystals are subjected to any convenient one Way, e.g. B. by mixers with low or medium speed for these purposes known types, dispersed therein, if necessary or desired, can be added to the solution of the dispersed aggregate crystals containing carrier substance one or more photoconductors or any other desired additives can be added. It should be noted, however, that the aggregate crystals in the dispersed state retain their crystalline form and are not redissolved.

Solvent of choice for the preparation of the photoconductive compositions and those therewith too coating recording materials are, for. B.

a variety of organic solvents for the polymeric carrier, e.g. B. Alkanes with about 5 to about 12 Carbon atoms including the cycloalkanes such as pentane, cyclohexane, isooctane, nonane, and decane Dodecane, including aromatic hydrocarbons

b5 borrowed the substituted by short-chain alkyl groups aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene and propylbenzene, ketones, e.g. B. Dialkyl ketones with 1 to about 3 carbon atoms in

the alkyl radical, such as dimethyl ketone and methyl ethyl ketone and mixtures of these solvents, of course the solvent must have practically no dissolving effect on the crystalline aggregate phase if they once formed

Examples of binders which are particularly suitable for use in the production of photoconductive layers well suited are polymers with a fairly high dielectric strength, the good ones represent electrically insulating film-forming carriers. Materials of this type are e.g. B. styrene / butadiene copolymers, Polyvinyltoluene / styrene copolymers, silicone resins, styrene alkyd resins, silicone alkyd resins, Soya alkyd resins, polyvinyl chloride), polyvinylidene chloride), Vinylidene chloride / acrylonitrile copolymers, Vinylidene chloride / vinyl chloride copolymers, polyvinyl acetate), vinyl acetate / vinyl chloride copolymers, Polyvinyl acetate), e.g. B. polyvinyl butyral), Polyacrylic and polymethacrylic esters, e.g. B. Poly (methyl methacrylate), Polyi, n-b'rtyl methacrylate), Poly (isobutyl methacrylate), polystyrene, nitrated polystyrene, polymethylstyrene, isobutylene polymers, polyester, z. B. Poly (ethylene alkaryloxyalkylene terephthalate), cellulose esters, phenol-formaldehyde resins, ketone resins, Polyamides, polycarbonates, polythiocarbonates, polyethylene glycol-co-bis-hydroxyethoxyphenylpropane terephthalate) and ring-substituted polyvinyl haloarylates. Process for making resins of this type are already known, for example the styrene alkyd resins according to the US Patents 2361019 and 2258423 getting produced. Suitable resins of the type v.ie in the photoconductive prepared according to the invention Layers that can be used are a copolymer of terephthalic acid and a mixture of 9 parts of 2,2-bis [4- (J3-hydroxyethoxy) phenyI] propane and 1 part of ethylene glycol; a methyl styrene thermoplastic molding resin; an unsaturated hydrocarbon resin; a vinylidene chloride / acrylonitrile copolymer and prepared by ester interchange between diphenyl carbonate and 2,2-bis-4-hydroxyphenylpropane Polycarbonate resins of various molecular weights. Other types of binders used in the photoconductive Layers that can be used are e.g. B. Materials such as paraffin and mineral waxes.

As substrate materials which can be coated with the sensitizer-containing photoconductive layers produced in accordance with the invention are, for. B. the most diverse types of electrically conductive substrate materials are suitable, such as paper (at a relative humidity of above 20%), aluminum-paper laminates, metal foils, such as. B. aluminum and zinc foils, metal plates, e.g. B. aluminum, copper, zinc, brass and galvanized plates, metal layers applied by vapor deposition to paper, for example made of silver, nickel and aluminum or conventional photographic film supports, e.g. B. those made of cellulose acetate or polystyrene. Electrically conductive materials, such as B. nickel, can be vapor-deposited in sufficiently thin layers on transparent film support in vacuo so that electrophotographic recording materials can be produced which can be exposed from either side of these recording materials. A particularly suitable electrically conductive support can be produced by using a support material, such as, for. B. polyethylene terephthalate with an electrically conductive layer which contains a semiconductor dispersed in a resin, coated or vapor deposited on the substrate in a vacuum. Such electrically conductive layers both with and without insulating barrier layers are e.g. B. in US Pat. No. 3,245,833. A likewise suitable electrically conductive coating can be produced from the sodium salt of a carboxy ester lactone of maleic anhydride and a vinyl acetate polymer. These types of electrically conductive

ι ο Layers and processes for their optimal manufacture and uses are described, for example, in US Patents 3,07,901 and 3,262,807.

The layer thickness of the photoconductive composition on the support can be further Limits can be varied. Usually a layer thickness is within the range of about 10 Microns to about 300 microns before drying suitable for purposes of the invention. The preferred The range of layer thickness is within the range of about 50 to about 150 microns before drying, although useful results can be obtained outside of this range. The resulting The dry thickness of the coating is preferably between about 2 and about 50 microns, although good results can also be obtained with a dry film thickness between about 1 and about 200 microns can.

After the photoconductive recording materials produced in the manner described above have been dried, they can be in any of the known electrophotographic Methods in which photoconductive layers are required can be used. One such procedure is the so-called xerographic process. One process of this type uses an electrophotographic Recording material kept in the dark and provided with an electrostatic surface charge, by placing it under a source of corona discharge.This uniform charge is due to the im Dark practically insulating property of the layer, d. H. because of the low electrical conductivity of the Layer in the dark, maintained by the layer. Those on the surface of the photoconductive layer generated electrostatic charge is then imagewise exposed by means of a conventional exposure process, for example by the contact copying method or by lens projection of an image, selectively derived from the surface of the layer, so that an electrostatic latent image is formed in the photoconductive layer. If you look at the surface exposed in the manner arises due to the fact that the light energy incident on the photoconductor is too a derivation of the electrostatic charge from the areas of the surface struck by light corresponding to the intensity of the lighting in a particular area, creates an electrostatic charge image.

The charge image generated by exposure is then developed or transferred to another surface and developed there, d. h, the loaded or unloaded Districts are made visible by treating them with a medium that is electrostatic contains responsive particles having an optical density. The electrostatically responsive developer particles can be in the form of a dust, i. H. in the form of a powder, or in the form of a pigment in one resinous carrier, e.g. B. in the form of a toner. A preferred method of application

such a toner on an electrostatic latent image for large area development consists in the Using a magnetic brush. Method of making and using a magnetic brush toner applicator are for example in U.S. Patents 2,786,439, 2,786,440, 2,786,441 and 28 74 063. There can also be a liquid development of the electrostatic latent image be applied. In the case of liquid development, the developer particles are electrically ι ο insulating liquid carrier applied to the image-bearing surface. Development process this Type are known and described, for example, in US Pat. No. 29 07 674. In the dry development process, The most commonly used method is to keep a permanent record in the Way that one selects a developer particle which has a low-melting point as one of its components Resin contains. The heating of the powder image then leads to the resin in or on the recording material melts. In this way the powder adheres permanently to the surface of the photoconductive Layer. In other cases there may be an electrostatic transfer of the generated on the photoconductive layer Charge image on a second carrier, e.g. B. paper, are carried out, which then after the Development and after melting (fixing) the final copy represents the method of the above Type are known and described, for example, in "RCA Review", Volume 15 (1954), pages 469 to 484. jo

The following examples are intended to explain the invention in more detail.

example 1

A 0.2 g portion of the dye 4- (4-dimethylami- J5 nophenyl) -2,6-diphenylthiapyrylium perchlorate and a 0.2 g portion of poly (4,4'-isopropylidenediphenylene carbonate) were added with stirring in 10 , 0 g of dichloromethane dissolved 5.0 g of toluene were added to the solution of the dye and the polymer, which led to partial precipitation of the dye. Sufficient, ie about 5 g, dichloromethane was added to redissolve the dye. About 50 g of n-hexane were added to the solvent system consisting of dichloromethane and toluene with stirring. After a few minutes, a bluish green, crystalline material precipitated from the mixture of the solvent system and the precipitation solvent. The crystals were separated from the solvent system by pouring the contents into a Buchner funnel containing filter paper and applying a slight vacuum to the funnel using a suction bottle. The crystals thus separated were then about 50minütiges heating to about 100 ⁰ C dried They were due to the fact that its w spectral absorption maximum at a wavelength of 685 lay nm, while that was the dye nm alone at 590 identified as an aggregate crystals.

Then, by dissolving 0.58 g of a mo- w>. Containing about 9% by weight of poly (vinyl alcohol) units differentiated polyvinyl butyral) and from 0.40 g of 4,4'-benzylidene-bis (N, N-diethyl-m-toluidine) in 9.0 g of toluene and by adding to each three of these solutions a separate part of the aggregate crystals prepared as above photoconductive compositions (coating compounds) produced. The weight of the first Crystals added to the solution was 0.04 g, that of the crystals added to the second solution was 0.08 g and that of the crystals added to the third solution 0.12 g. Any of the compositions thus obtained was shaken in a metal container with small steel balls for about 5 minutes to ensure even To achieve mixture. Each of the compositions was then applied to a wet film thickness of 100 microns on an electrically conductive support consisting of a poly (ethylene terephthalate) film with a applied thereon copper (I) iodide layer, as described in US Pat. No. 3,245,833 and dried.

The electrophotographic recording materials obtained in this way were then electrostatically charged under a negative corona discharge source until the surface tension, measured with the aid of an electrometer probe, had reached a value of about 600 volts. The charged recording material was then exposed through a gray scale with graduated density with a tungsten light source of 3000 ° K. The exposure led to a reduction in the surface tension of the recording material at each step of the gray scale from an initial voltage Vo to a slightly lower voltage V, the exact value of which is the respective amount of light hitting the respective district, measured in lux-seconds (seconds meter candles). The values obtained in this way were then entered in a diagram in which the surface tension V was plotted against the logarithm of the exposure for each step. The respective negative sensitivity of the photoconductive composition can then be expressed by the reciprocal value of the exposure required to reduce the surface tension to a fixed, arbitrarily selected value. In the following, unless otherwise stated, the respective negative sensitivity wedge is expressed by the numerical expression 104 divided by the exposure in lux-seconds required to reduce the surface tension from 600 volts by 100 volts. The sensitivities of the recording materials obtained in this way were 1600, 3200 and 4000 with increasing concentration in cocrystalline complex crystals. For comparison, a composition was prepared as described above for the preparation of the cocrystalline complex, but the polycarbonate was omitted. The resulting precipitate then consisted only of the dye. The dye crystals were incorporated into a composition containing a photoconductor and applied to a support as above for the preparation of electrophotographic recording materials. The sensitivities of the recording materials obtained were below 20. It can be seen that the crystals obtained by the process of the invention actually represent a cocrystalline complex of the dye and the polymer, as is indicated in US Pat. No. 3,615,414.

Example 2

The crystals of the cocrystalline complex prepared as in Example 1 were converted into a photoconductive device ge composition, similar to that of the example! 1, incorporated, this time a polystyrene resin mi another average molecular weight a1: binder for the photoconductive composition and cyclohexane were used as coating solvents. The weight of the one used

Aggregate or the cocrystalline complex crystals used was 0.12 g. The coating conditions were the same as in Example 1. The sensitivity of the recording material obtained was 800, while the sensitivity of a recording material made only from the dye instead of the cocrystalline complex was 0. This was because the dye alone was the photoconductor in a polystyrene binder system not sensitized. ι ο

Example 3

The procedure of Example 1 for the preparation of cocrystalline complex crystals was repeated. This time, however, a 2.5 wt .- / vol .-% solution of the dye in dichloromethane was prepared, to the a 2.5 wt .- / vol .-% solution of the resin, also in dichloromethane, was added. The one used The dye and the resin used were the same as in Example 1. To the dye-polymer solution no further solvent was added. A certain amount of ligroin was then added to the solution added dropwise to a boiling range of about 63 to 75 ° C, the amount about 2.5 times the volume of the was the solvent used to dissolve the dye and the polymer. As in example 1 a precipitation of the cocrystalline complex occurred, then the crystals were isolated and dried. Then the crystals were used to produce three recording materials as in jo Example i. These recording materials each exhibited electrophotographic responsiveness which corresponded to that of Example 1. The crystals were due to the occurrence of the shift identified as the complex at the wavelength of maximum spectral absorption.

Example 4

The process described in Example 3 was repeated, this time using 2.0% by weight / volume% solutions of the dye and the polymer and 1,2-dichloroethane as solvents. The precipitation liquid was η-hexane, the amount of which was about 2.4 times the volume of the solvent used. Crystals were obtained which were similar to those of Example 3, which had the characteristic spectral absorption shift of the aggregate or cocrystalline complex and which gave the recording materials produced therefrom correspondingly high sensitivities. vi

Example 5

The procedure of Example 3 was repeated, this time at twice the weight concentration Polymer was used in the starting solution. The precipitation liquid was the liquid of the example 4, their amount was 2.4 times the volume of the solvent. The results obtained corresponded those as obtained in Examples 3 and 4. t> o

Example 6

Using the dye and the polymer according to Example 1, a dye-polymer solution was obtained produced, the 2.0 wt .-% of both t> 5 dye and polymer in dichloromethane contained. The order of addition according to Example 1 was reversed by adding the dye-polymer solution was added dropwise to the precipitation liquid. The precipitation liquid was the ligroin of Example 3, its volume was 3 times that of the dye-polymer starting solution. Immediately after the solution was added to the precipitation liquid, aggregate crystals began to form form. After the entire volume of the initial solution was added, the crystals became separated and dried as in the previous examples. The procedure of this example is preferred since the total precipitation took a much shorter time. Identification of the crystals as Aggregate crystals were carried out as above, as was the preparation of an electrophotographic Element that showed a correspondingly high sensitivity in the test.

Example 7

A solution was made from the following ingredients:

4- (4-dimethylaminophenyl) -2,6-diphenylthiapyrylium fluoroborate (Dye II) 2.7 g

4- (4-Dimethylaminophenyl) -2- (4-ethoxyphenyl) -6-phenylthiapyrylium fluoroborate
(Dye III) 03 g

Polycarbonate resin 3.0 g

Methylene chloride 525 ml

Toluene 375 ml

This solution was added dropwise to 4,500 ml of hexane, which resulted in the formation of aggregate crystals. The aggregate resultant precipitate was separated by suction filtration, and 16 hours at 6O ⁰ C dried the aggregate dry crystals were then used to prepare the following compositions:

Together- ingredients lot settlement A Chlorinated polyethylene 1.2 g (65.8% Cl) (Binder) 4,4'-diethylamine-2,2'-dimethyl- 0.8 g triphenylmethane (photoconductor) Aggregate crystals 0.2 g toluene 12 ml B polyvinyl vinylidene chloride 1.2 g 4,4'-diethylamine-2,2'-dimethyl- 0.8 g triphenylmethane (photoconductor) Aggregate crystals 0.2 U toluene 12 ml C poly (vinyl m-bromobenzoate-co- 1.2 g vinyl acetate) 4,4'-diethylamino-2,2'- 0.8 g dimethyl triphenyl methane (Photoconductor) Aggregate crystals 0.2 g toluene 12 ml

For each of the above compositions, porcelain balls having a diameter of Vs inch was added and two at a time

55 $ 90

Shaken for hours in a high frequency, low amplitude vibratory mixer. Each of the The resulting formulations were applied to a wet film thickness of 0.1 mm (0.004 inches) Nickel (optical density 0.4) coated substrate

applied for the production of an electrophotographic recording material which, as described above, was examined for its sensitivity. The sensitivity values obtained are as follows specified.

Recording material

No.

Together- Positive sensitivity Negative sensitivity

Settlement _in shoulder- in sag- in shoulder- in sag

area area area slope area

1 A. 9000 1600 8000 400 2 B. 9000 1200 5000 550 3 C. 10,000 1300 5700 630

Similar results were also obtained when using dye I and 4- (4-dimethylaminophenyl) -2-

(4-ethoxyphenyl) -6-phenylthiapyrylium perchlorate
(Dye IV) obtained.

Example 8

Starting solutions were prepared, each containing:

Dye II
Dye III
Polycarbonate resin
Methylene chloride
toluene

0.44 g
0.06 g
3.2 g
350 ml
250 ml

30th

A solution was added dropwise to 3000 ml of hexane and with the aid of a dry ice / acetone bath to - 8O ⁰ C cooled. The other solution was added to 3000 ml of hexane which was kept at room temperature (about 23 ° C). The resulting aggregate precipitates were collected by suction filtration. In the investigation of the two precipitates was noted that the much finer particle size prepared at -8O ⁰ C had as that prepared at room temperature.

Example 9

Four solutions were made from the ingredients listed below:

Solution solution solution
No. 1 No. 2 No. 3

solution
No. 4

35

40

45

Lexan 145 3.5 g 3.5 g 1.2 g 13.3 g Dye II 0.44 g 0.44 g 0.15 g 6.65 g Dye III 0.06 g 0.06 g 0.02 g - Methylene chloride 350 ml 350 ml 118 ml 1750 ml toluene 250 ml 250 ml 83 ml 1250 ml

55

The solution No. 1 was added dropwise to 3000 ml of heptane, the solution No. 2 became 3000 ml Cyclohexane was added dropwise, the solution No. 3 was added dropwise to 1000 ml of 2,2,4-trimethylpentane and the Solution # 4 became 15,000 ml of a solvent mixture of branched chain isoparaffinic hydrocarbons with a boiling point range of 160-177 ° C was added dropwise. The aggregate precipitations obtained in this way were again collected by suction filtration. The investigation of this precipitation in the binder / photoconductor systems of Example 7 showed that the compositions obtained had a exhibited high xerographic sensitivity.

Example 10

A mixture of 0.9 g of polyvinyl carbazole, 0.2 g of the aggregate crystals of Example 7 and 12 ml of benzene was prepared by stirring the polyvinyl carbazole into the solution, adding the aggregate crystals and using a vibratory shaker for two hours using porcelain balls moved 0.32 cm in diameter. The resultant formulation was then at 27 ° C in a wet thickness of 0.1 mm at 27 ⁰ C on an (optical density 0.4) with a nickel coating provided substrate. A comparative coating was also prepared containing 1.8 g of polyvinyl carbazole, 30 ml of benzene, 0.2 g of polycarbonate resin, and 0.18 g of Dye II and 0.02 g of Dye III. The Lexan and the dye of this composition became simply solved together and were in the form of a homogeneous combination, not in the form of a cocrystalline complex. This comparative coating was also used to prepare an electrophotographic recording material as described above, and the two recording materials were examined for their sensitivity. The comparative recording material containing no aggregate had a 100 V shoulder sensitivity which was more than ten times lower than that of the recording material containing the aggregate. The 100 V sensitivity in the toe area of the comparison material was 0.

Claims (8)

Patent claims: 1. A process for the preparation of a cocrystalline and complex of a pyrylium dye with a electrically insulating polymer containing an alkylidene diarylene radical in the repeating unit having, characterized in that one a) the dye and the polymer in a ι υ containing a halogenated hydrocarbon Dissolves solvents in which their solubilities are practically the same, b) the solution of the dye and the polymer slowly with a halogen-free, nichtpola- ι s Ren, organic precipitation liquid in which the dye and the polymer are insoluble are combined to precipitate the cocrystalline dye-polymer complex and c) the complex formed by the solvent and separates the precipitation liquid. 2. The method according to claim 1, characterized in that the polymer is a compound is used, which has a remainder of the formula in the repeating unit: O
-CH ₂ -OCO where mean: R4 and R ₅ individually each represent a hydrogen atom, an optionally substituted alkyl radical with 1 to 10 carbon atoms or an optionally substituted aryl radical or together the number of carbon atoms required to complete a cyclic hydrocarbon radical, the total number of carbon atoms in R ₄ and Rs being up to 19 , Re and R7 each represent a Wassenitoffatom, an alkyl radical having 1 to 5 carbon atoms or a halogen atom and Re a divalent remainder of any of the following Formulas: Il r ^ r \ —O — c — o— —C — o— Il -CO-CH ₂ -O CH ₃ 30th 35 40 45 50 55 60 65 3. Process according to Claims 1 and 2, characterized in that the polymer is used a carbonate polymer is used which has recurring units of the formula: R ₄ O I Il —R— C — R — O — C— ΟΙ R ₅
where mean: R is a phenylene radical and R4 and R ₅ individually each represent a hydrogen atom, an alkyl radical with 1 to about 10 carbon atoms or an aryl radical, or together the number of carbon atoms required to complete a cyclic hydrocarbon radical, the total number of carbon atoms in R ₄ and R _{5 being} up to 19 4. Process according to claims 1 to 3, characterized in that one is used as a pyrylium dye Pyrylium or thiapyrylium dye salt is used. 5. The method according to claim 4, characterized in that there is a compound as the dye salt the formula used: where mean: Ri and R2 each represent a phenyl radical, R _{3 is} an alkylamino substituted phenyl radical with 1 to 6 carbon atoms in the alkyl radical, X is an oxygen or sulfur atom and Ζ ^{θ is} an anionic radical 6. Process according to claims 1 to 5, characterized in that one is used as the precipitation liquid organic liquid with a dielectric constant less than about 5 is used 7. The method according to claim 6, characterized in that there is an alkane as the precipitation liquid having from about 6 to about 12 carbon atoms, ligroin, or a mixture thereof are used. 8. Process according to claims 1 to 7, characterized in that there is an organic solvent system used that consists of a chlorinated alkane and / or a chlorinated aromatic Hydrocarbon. —C — O — CH-