DE1522586B1 - Electrophotographic recording material - Google Patents

Description

The invention relates to an electrophotographic recording material having a layer support and a photoconductor-binder layer.

It is known e.g. Using 893 546-and 894 371, electrophotographic for performing method recording materials for example, from the USA' Patents 2 663 636, 2 986 467 and 3 121 006, the German i Patents 1,046,493 and 1,129,051 as well as British Patent Specifications consisting of a 'substrate and a applied thereon layer of photoconductor particles, which are dispersed in an electrically insulating binder to use. Recording materials with photoconductor-binder layers, the photoconductor of which consists of zinc oxide particles and which are, for example, from the journal RCA Review, 1954, pp. 469 to 484, and the USA patents 3,052,539 and 3,052,540 are known.

As an electrically insulating binder for the photoconductor particles are the most diverse synthetic polymers from the specified patent documents, z. B. silicone resins; Polystyrenes and polyesters, such as polymethacrylic acid alkyl esters, have become known. Non-polymeric compounds have been found to act as binders for the photoconductor particles various disadvantages not proven. So, for example showed that the insulating properties of non-polymeric binders are often inadequate are and / or that the photoconductive produced using non-polymeric insulating binders Layers adhere poorly to the support of the electrophotographic recording material. It has also been shown that the Sensitivity of the photoconductive layers is often too low and that the binder with many Sensitizing dyes not tolerated. In the end it was found that discoloration often occurs when using non-polymeric binders the photoconductive layer occur.

The object of the invention is to provide an electrophotographic Specify recording material with a layer support and a photoconductor-binder layer, its photoconductor-binder layer even when the relative humidity of the environment is high electrically conducts very little and is lighter than the known recording materials.

The subject matter of the invention is based on an electrophotographic recording material a layer support and a photoconductor-binder layer and is characterized by that the binder is 25 to 100 percent by weight of one Cane sugar ester, a bisphenol or a mixture contains from both.

The use has proven to be particularly advantageous proved by mixtures of a cane sugar ester and a bisphenol. Advantageously contains the binder in this case at least 5 percent by weight of a bisphenol and at least 25 percent by weight of a cane sugar ester.

The weight ratio of zinc oxide to the binder mixture in the photoconductive layer can be between 1: 1 and 6: 1, preferably 3: 1 and 4: 1, lie.

The invention achieves that recording

-iiungstnaterialien with photoconductive layers manufacturer ^ ⁶ can be provided, which electrically conduct very little even at high relative humidity of the environment. Furthermore, the image quality which can be achieved with the recording material according to the invention is superior to the quality of such images which can be obtained using known electrophotographic recording materials with a zinc oxide binder layer. A particular advantage of the electrophotographic recording material according to the invention is the considerable weight saving of copies made with it compared to those that can be made with the known electrophotographic recording materials which contain zinc oxide dispersed in a polymeric binder, since 2.0 g per 0 , 0929 m ^{2 of} a zinc oxide, cane sugar ester and / or bisphenol mixture are sufficient to obtain layers with good electrophotographic properties. Such layers are about a third lighter than corresponding layers consisting of zinc oxide and a polymeric binder. In addition, the photoconductive layers produced from mixtures of a cane sugar ester and a bisphenol as a binder also have advantageous mechanical properties.

The electrophotographic recording material of the invention is also excellent Sensitivity, a sufficiently large dark electrical resistance, favorable charge decay characteristics and good surface properties. In addition, it is relatively cheap to produce.

The photoconductor-binder layer of an electrophotographic Recording material according to the invention can be combined with one or more of the known usual sensitizing dyes must be sensitized in order to increase the sensitivity of the layer improve and to widen the spectral response range of the photoconductor.

Furthermore, for the production of the recording materials a wide variety of known customary electrically conductive substrates are used will.

As cane sugar esters, especially esters made from cane sugar and monocarboxylic acids, z. B. cane sugar acetate, cane sugar benzoate, cane sugar diacetate hexaisobutyrate and cane sugar benzoate isobutyrate, proven beneficial.

As bisphenols, in particular, those of the formula

HO

OH

Vj- /

R ₁

R,

proved to be advantageous in which X is a single bond or any divalent substituent and R ₁ and R are any monovalent substituent.

Particularly suitable compounds of the formula given are:

4,4'-sulfainyldiphenol,

l, 3- (J-oxyphenyl) propane,

p, p'-bisphenol,

-U'-Dipropyl (p.p'-diphenol), 4,4'-Oxydipl) enol,

Diiesorcycuifid.

4,4'-sulfonyldiphenol,

2,2'-dioxybenzophenone,

2,2'-4,4'-tetraoxybenzophenone, 2,2'-dioxy-4-methoxybenzophenone, 2,2'-Dioxy-4,4'-dimethoxybenzophenone, 2,2'-Dioxy-4-n-octyIoxybenzophenone, 4,4'-Dioxy-3,3'-dinitrobenzophenone, l, 3- (4-oxyphenyl) propane,

2,2 '- (Ethanylidendinitrilo) -diphenoI, «,«' - (Ethylenedinitrilo) -di-o-cresol, Bis (2-oxyphenyl) methane,

Bis (4-oxyphenyl) methane,

Bis (2,6-di-t-butyl-4-oxyphenyl) methane, 1,1-bis (4-oxyphenyl) ethane,

l, l-bis- (4-oxyphenyl) -2-methylpropane, l, l-bis- (4-oxyphenyl) -3-methylbutane, 1,1-bis- (4-oxyphenyl) -n-butane, 2,2-bis- (4-oxyphenyl) -propane, 2,2-bis (4-oxyphenyl) butane,

2,2-bis- (4-oxyphenyl) -3-methylbutane, 2,2-bis- (4-oxyphenyl) pentane,

2,2-bis- (4-oxyphenyl) -4-methylpanolan, 2,2-bis- (4-oxyphenyl) -hexane,

2,2-bis (4-oxyphenyl) nonane,

2,2-bis- (3-t-butyl-4-oxyphenyl) propane, 3,3-bis (4-oxyphenyl) pentane,

Bis- (4-oxyphenyl) -phenyimethane, bis- (4-oxyphenyl) -naphthylmelhan, bis- (4-oxyphenyl) -4-methylphenylmethane, Bis (4-oxyphenyl) -2-hydroxymethylphenylmcthan,

Bis- (4-oxyphenyl) -2-chlorophenylmethane, bis- (4-oxyphenyl) -2,4-dichlorophenylmethane, Bis- (4-oxyphenyl) -4-chlorophynylmethane, bis- (4-oxyphenyl) -3,4-dichlorophynimethane. Bis- (4-oxyphenyl) -2-carboxyphenylmethane, bis- (3-methyl-4-oxyphenyl) -phenylmethane, Bis- (4-oxyphenyl) -diphcnylmethane, 1,1 - bis- (4-oxyphenyl) -1 -phenylethane, 1,1 -Bis- (4-oxyphenyI) -1 - (4-methylphenyl) -iithane, 1,1 -Bis- (4-oxyphenyI) -1 -naphthylethane, l, l-bis (4-oxyphenyl) -l- (3-fluorophenyl) -ethane, l, l-bis- (4-oxyphenyl) -l- (4-fluorophenyl) -ethane, 1,1 -Bis- (4-oxyphenyl) -1 - (3,4,5-trifluoropheny I) -iithane,

1., 1 -Bis- (4-oxyphenyl) -1 - (3-chlorophenyl) -Hthane, l, l-Bis- (4-oxy phenyl) -l- (4 ~ chlorophenyl) -ethane, 1,1 -Bis- (4-oxyphenyl) -l - (3,4-dichlorophenyl) -

ethane,
1,1 -Bis- (4-oxy phenyl) -1 - (2,5-dichloropheny 1) -ethane,

lJ-bis- (4-oxyphenyl) -l- (4-bromophenyi) -ethane, l, l-bis- (3-methyl-4-oxyphenyl) -l- (4-chloro-

phenyl) ethane,
l, l-bis (3-methyl-4-oxyphenyl) -l- (3,4-dichloro-

phenyl) ethane,
1, l-Bis-P ^ -dichlor ^ -oxyphenylH-ß ^ -dichlor-

phenyl) ethane or
1,1 -Bis- (4-oxy phenyl) -1 -phenylpentane.

Suitable bisphenols also include 4,4 '- [2-norbornyliden] -bis- [2,6-dichloropheuene] and esters with more than one bisphenol unit, such as /. B. which by condensation of 2 mol 4,4'-bis- (1-oxyphenyD-pentanoesüire with a glycol, /. B. a CJlykol the formula C ₃ ,, H _, (C) H) ₂ holds the Dieter.

To produce the photoconductor binding layers, the bisphenols and raw thickeners can be mixed with non-polymeric compounds. / .. B. with u-phenylp-cresol, guaiacol, eugenol, 2-naphthyl benzoate or 1,4-diphenyl-1,3-butadiene.

Particularly good results are achieved when using a binding agent mixture of cane sugar octaacetate, a bisphenol and rosin obtained.

The photoconductor is preferably made of zinc oxide. However, it can also be of the most varied ίο other known photoconductors can be used.

example 1

1 g of 2,2-bis (4-oxyphenyl) pentane were dissolved in 6.75 g of acetone, whereupon 3.5 g of a photoconductive zinc oxide, which with 1.0 · H) " ⁷ mol of bromophenol blue and 0.84 · K) " ⁷ moles of anhydro-3,3'-di-j>'- carboxyethyloxacarbocyanine hydroxide per mole of zinc oxide was added to the solution. The mixture was then milled in a steel cylinder by means of a steel roller for 15 minutes. The homogenized mixture was applied to a layer support through a 0.1 mm wide slot using a coating knife.

The recording material was allowed to air dry overnight. The photoconductor-binder layer produced on the support was cohesive, flexible and resistant to abrasion.
From the electrophotographic recording material obtained, the following were then determined: the initial charge potential (V ₀ ), the dark decay (K, ₂ ) of the charge, indicated by the charge potential of the surface 1 minute after the electrification, and the relative photographic sensitivity. The following results were obtained:

K, = 340 volts; K ₁₂ = 190 VoH; relative sensitivity = 204.

Example 2

The procedure described in Example 1 was repeated. However, this time 1 g of cane sugar benzoate isobutyrate used in place of bisphenol. The photoconductor-binder layer of the obtained The recording material was relatively soft. The following measurement results were obtained:

V ₀ = 415 volts; F ₁ , = 330 volts; Sensitivity = 104.

Example 3

20 g cane sugar diacetate hexaisobutyrate and 20 g l, I-bis (4-oxyphenyl) -l- (4-chlorophenyl) ethane were dissolved in 250 g of acetone, whereupon the solution with 140 g Zinc oxide, which, as described in Example 1, sensitizes had been mixed. The mixture was ground in a ball mill for 21 hours, whereupon the homogenized mixture is applied to an electrically conductive paper by means of an extruder became. The coated recording material was then heated to from 62 to 68.degree Air dried. The recording material was then tested as described in Example 1, however prior to testing in the dark in air of 59% relative humidity overnight at a temperature of

^f 'i> 23 C conditioned. The following measurement results were obtained:

V ₁₁ ■■ - 370 volts; V ₁ , ^ = 275 volts; Sensitivity - 250.

Example 4

32.5 g cane sugar octaacetate, “2.5 g r.l-bis (4-oxypheny!) - l- (4-chlorophenyI) ethane and 5 g of rosin were dissolved in 250 g of acetone, whereupon 140 g of zinc oxide, which, as described in Example 1, had been sensitized. added and the mixture ground in a ball mill. Using this mixture, an electrophotographic recording material was obtained as in Bite = 104. game 3 described, manufactured and tested. The following results were obtained:

V ₀ = 450 volts: V ₁ , ₂ = 380 volts: sensitivity = 164.

dissolved in 250 g of acetone, whereupon 140 g of the solution Zinc oxide, which, as described in Example 1, sensitizes was added and the mixture was ball milled. The received Dispersion was then, as described in Example 3, applied to a layer support, followed by the layer dried and the recording material was tested. The following results were obtained:

V ₀ = 440 volts; V _{i / 2} = 355 volts; Sensitive-

Claims (1)

Claim; Example 30 g cane sugar octaeaetate, 5 g cane sugar diacetate hexaisobutyrate, 2.5 g rosin and 2.5 g 4.4 '- (2-norbornylidene) -bis- {2,6-dichlorophenoi) were Electrophotographic recording material comprising a support and a photoconductor binder -Layer, characterized that the binder contains 25 to 100 percent by weight of a cane sugar ester, a bisphenol or a mixture of both.