DE2749982C3 - Electrostatographic recording material - Google Patents

Description

(6)

CH-CH,

contains.

2. Recording material according to claim 1, characterized in that it is electrically conductive layer 0.1 to 15 parts by weight of optical brightener per 100 parts by weight of electrically conductive Layer contains.

3. Recording material according to claim 1, characterized in that it is in the insulating Layer 0.01 to 5 parts by weight of optical brightener per 100 parts by weight of the plastic of the insulating Layer contains.

4. Recording material according to claim 1, characterized in that the insulating layer contains a synthetic resin powder dispersed as a pigment.

The invention relates to an electrographic recording material from an electrically conductive paper, from a paper and an electrically conductive one Layer, or from a paper that is provided with an electrically conductive layer on both sides, as well as each with an insulating layer which contains a plastic and which can contain a pigment.

Electrostatographic recording materials consist of electrically conductive paper and electrically conductive layers of insulating plastics and the like. To generate the image, each existing electrically conductive layer a latent electrostatic image by means of an image-correct signal formed and then made visible with the help of a powdery toner electrostatographic Recording materials have come into the fields of facsimile production, high speed copying and the like found widespread use.

The known electrostalographic recording materials (hereinafter referred to only as "recording materials" is obtained by first working in an electrically conductive paper, z. B. soaking with or dispersing electrically conductive substances, e.g. B. organic Polyelectrolytes, inorganic electrolytes, metal powder and the like in a paper backing, e.g. B. conventional paper, art paper and the like, or by having one or both surface (s) of the Paper backing with a conductive coating containing such an electrically conductive substance

provides, produces and then on the electrically conductive paper an essentially made of plastics, such as polystyrene, polyacetals, acrylic resins and the like, forms an existing electrically conductive layer.

A disadvantage of recording materials produced in this way, however, is that they are due to the impregnation with electrically conductive substances and the electrically conductive layers applied thereon with regard to their surface whiteness is inferior to normal paper. If you develop a latent electrostatic biloes can create a visible image with the help of a liquid developer liquid developers used penetrate into the recording material and thereby further the degree of whiteness to decrease. As a result, the density difference between the image detectors becomes. and the non-image districts (i.e. the background areas) are further reduced, so that it is difficult to obtain clean and sharp copies of the image can produce. To avoid these difficulties, the electrically conductive layer has already been used inorganic white pigments, e.g. B. titanium dioxide, zinc oxide, calcium carbonate, silicon dioxide and the like, incorporated.

By incorporating other inorganic pigments into the electrically conductive layer, the Certainly increase the degree of whiteness up to a certain point, but the improvement that can be achieved is in the Still inadequate with regard to the production of high-contrast image recordings. About that In addition, the incorporation of inorganic white pigments into the electrically conductive layer results in a Impairment of their important charging properties.

The invention was based on the object of providing an electrostratographic recording material create that has excellent paper-like properties and has a high degree of whiteness. About that In addition, it should be easy to manufacture and acceptably high-contrast image recordings deliver.

The invention thus relates to an electrostatographic recording material as described at the beginning Kind, which is characterized in that it is in the paper, in the electrically conductive layer and / or an optical brightener of the formula in the insulating layer:

where Xi equals the groups
-NH ₂

CH ₂ CH ₂ OH

fa5 /

- N

CH ₂ CH ₂ OH

—Ν

—Ν

CH ₂ CH ₂ OH

"CH, CH, OH CH, CH, OH

"CH ₂ CH ₂ OH CH, - CH,

—N O

CH ₂ -CH ₂

CH, -CH,

—Ν

or

CH ₂ -CH ₂

- NH- ^ ~ ^> and Y ₁ equal to the groups

- NH- \ /

SO ₃ Na

SO ₃ Na

or

CH ₃

(C)

(d)

where X ₂ equals the groups

W-OCH ₃

or

OCH ₃

IO

is;

an optical brightener of the formula:

(e)

20th

NaSO ₃

an optical brightener of the formula:

25th

an optical brightener of the formula:

35

C-CH = CH-C C ₂ H ₄ OH

and / or an optical brightener of the formula:

NaO ₃ S

50

contains.

55 An electrically conductive paper which can be used according to the invention is obtained by incorporating e.g. B. by is, whereby in a connection only those with the same impregnation with or dispersion of electrical Groups denoted by letters contain conductive substances and possibly binders to be allowed to; in paper, e.g. B. common paper or art paper and

an optical brightener of the formula: 60 the like, or by coating at least one

Surface of paper with an electrically conductive substance and optionally a binder.

In the manufacture of electrically conductive paper, the fluorescent brighteners are preferably applied (2) 65 paper incorporated electrically conductive layers, as they increase the whiteness even more improve if they are as close as possible to the surface of the paper.

X ₂ -C-NH

CH =

SO ₃ Na

Suitable electrically conductive substances are, for example, inorganic salts such as NaCl, CaCl2 and the like, metal powder, e.g. B. Al, Ni, Cu and the like, organic polyelectrolyls, e.g. B. Polyvinylbenzyliriniethylainmoniumchlorid and Polystyrolammonium- ^r > sulfonate and the like. These electrically conductive substances can, if necessary, in combination with binders, e.g. B. polyvinyl alcohol, starch, vinyl acetate resins, acrylic resins, styrene / Buladiene copolymers and the like, are used. ι ο

An electrically conductive layer is provided on at least one rope of the electrically conductive paper. Plastics suitable for forming the electrically conductive layer are, for example, polyvinyl acetate, Polystyrene, polyvinyl chloride, vinyl acetate / vinyl chloride copolymers, Polymethacrylic acid esters, polyvinylidene chloride, vinylidene chloride / vinyl chloride copolymers. Polyvinyl acetate, polyester, epoxy resins and the like.

If, according to the invention, fluorescent brighteners are used in electrostalographic recording materials accommodates, the fluorescent brighteners are preferably dissolved in a suitable solvent and applied to the recording material in the form of the solution. This is where the fluorescent brighteners go in the molecular state in the recording maicrials above.

The amount of fluorescent brighteners in the electrically conductive layers is in the range of 0.1 up to 15 parts by weight per 100 parts by weight total ji> solids content, d. H. treating agent having a low electrical resistance. The amount of fluorescent brighteners in the insulating layer is preferably in the range of 0.01-5 Part (s) by weight per 100 parts by weight of insulating plastic. It can also be two or more fluorescent brighteners are used in combination with one another.

Although the fluorescent brighteners of the electroconductive layer in an amount of more than 15 Parts by weight per 100 parts by weight of solid electroconductive substance can be incorporated thereby no longer increasing the degree of whiteness. When the fluorescent brightener is the insulating Layer incorporated in an amount exceeding 5 parts by weight per 100 parts by weight of insulating plastic become the charging properties of the recording material adversely affected.

The electrically conductive layer and the insulating layer may optionally contain pigments, e.g. B. silicon dioxide. lon. Calcium carbonate. Barium carbonate and the like, as well as opaque pigments such as zinc oxide and Titanium oxide, in addition to the plastics mentioned (binders), are incorporated.

The content of these pigments should, however, based on 100 parts by weight of solid plastic, expediently below 200 parts by weight, preferably 10 to 150 parts by weight. Further the insulating layer can also contain a powdered plastic. In this case one obtains eo a particularly advantageous embodiment of a recording material according to the invention, its Whiteness is higher, which can be written on with pencils and ink and whose charging properties (the insulating layer) are not impaired. Suitable plastics are, for example, polyvinyl chloride, Polystyrene, cured melamine resins and the like.

In the following, the production of a recording material according to the invention is explained in more detail using an example. First, an electrically conductive layer is formed on one or both surface (s) of paper. This electrically conductive layer is obtained by applying a solution of an electrically conductive substance in water or an alcohol and the like or a solution of an electrically conductive substance and a fluorescent brightener in water or an alcohol and the like to the paper and drying the applied solution. The layer in question is preferably obtained by applying a dispersion of an electrically conductive substance or an electrically conductive substance and a fluorescent brightener in a suitable binder, e.g. B. polyvinyl alcohol, starch and the like, onto the substrate surface with the aid of suitable charging devices and drying the applied dispersion. The amount of dry electrically conductive layer is 1 to 10 g / m ² .

Then an insulating layer is produced by applying a solution of an insulating plastic or an insulating plastic and a suitable amount of fluorescent brightener to the electrically conductive layer obtained by means of conventionally known application devices and drying the applied solution! When the process steps outlined are carried out, a recording material according to the invention is then obtained. The amount of the dry insulating layer is expediently 3 to 15 g / m · ^{1 support area} .

A recording material produced in the manner described according to the invention shows excellent paper properties and is indicated by the addition fluorescent brighteners are not impaired in their properties. So if you are with a If the recording material according to the invention carries out an image recording, a clean one is obtained and sharp picture.

example 1

1.5 parts by weight of finely divided silica powder and 0.3 part by weight of a stilbene type fluorescent brightener of the formula (1) (a) are thoroughly dispersed in 100 parts by weight of a 15% aqueous solution of a commercially available electroconductive substance. The dispersion obtained is applied to both sides of a wood-free paper with a paper weight of 60 g / m ² by means of a wire splint in such a way that the layer weight after drying is about 3 g / m ^{2 of support} surface on each side. Then the whole thing is now calendered, whereby an electrically conductive paper is obtained.

A solution of 20 parts by weight of polyvinyl chloride powder in 100 parts by weight of a 15% polystyrene solution is applied to one side of the conductive paper produced in the manner described in such a way that the weight of the recording layer or insulating layer obtained after drying is about 5 g / m ^{2 of support} surface amounts to

The recording material obtained has a white color and paper-like properties. With the Tests carried out on the recording material obtained provide those given in the table below Properties.

Example 2

100 parts by weight of a 10% strength aqueous polyvinyl alcohol solution, 5 parts by weight of finely divided silicon dioxide powder and!, 5 parts by weight of a fluorescent brightener of the stilbene type of the formula (l) (c) are dispersed in 100 parts by weight of a 15% strength aqueous solution of a commercially available electrically conductive substance. The dispersion obtained is applied to one side of wood-free paper with a paper weight of 60 g / m ² carrier surface using a wire rail in such a way that the electrically conductive layer has a weight of about 5 g / m ² carrier surface after drying. The whole is then calendered, whereby an electrically conductive paper is obtained.

A solution of 5 parts by weight of a powdered hardened melamine resin in 100 parts by weight of a 15% solution of methyl methacrylate in toluene is applied to the electrically conductive paper produced in the manner described by means of a wire bar in such a way that the amount of the recording layer or insulating layer obtained is about 5 g / m ^{2 support} area.

The recording material produced in the manner described has a white color and paper-like color Properties. Tests carried out with the recording material obtained provide those in the later results given in the following table.

Example 3

15 parts by weight of a polyvinyl acetate emulsion (solids content: 50%), 20 parts by weight of clay and 0.75 part by weight of a fluorescent brightener of the triazole type of the formula (4) are dispersed in 100 parts by weight of a 15% strength aqueous solution of a commercially available electrically conductive substance. The dispersion obtained is applied to both sides of a hol / free paper with a paper weight of 60 g / m ² by means of a wire bar in such a way that the amount of electrically conductive layer after drying is about 5 g / m ^{2 of support} surface. Then the whole thing is calendered. whereby an electrically conductive paper is obtained.

The electrically conductive paper produced in the manner described is applied by means of a wire bar a solution of 3 parts by weight of silicon dioxide in 100 parts by weight of a 15% strength vinyl acetate solution a vinyl chloride / vinyl acetate copolymer

• {Moiv ratio: vinyl chloride / vinyl acetate = 87/13), which was produced by comminuting and mixing in a ball mill, applied in such a way that the amount of recording layer or insulating layer formed after drying is about 5 g / m ^{2 of support} surface.

The recording material obtained has a white color and paper-like properties. With the Tests carried out on the recording material obtained provide those given in the table below Results.

Example 4

30 parts by weight of clay and 100 parts by weight of a 10% strength aqueous polyvinyl alcohol solution are dispersed in 100 parts by weight of a 15% strength solution of a commercially available electrically conductive substance. The dispersion obtained is applied by means of a wire rail to one side of wood-free paper with a paper weight of 60 g / m ² carrier surface in such a way that the amount of electrically conductive layer after drying is about 8 g / m ² carrier surface. The whole is then calendered, whereby an electrically conductive paper is obtained.

Then 3 parts by weight of titanium dioxide in 100 parts by weight of a 15% solution of polystyrene in Toluene entered. The suspension obtained is mixed with so much of a 5% solution of N-phenyl-2,3-diphenylpyrazolone (fluorescent brightener) added that the final concentration of fluorescent brightener 1 G ew .-%.

The dispersion prepared in the manner described is applied to the electrically conductive paper support by means of a wire bar in such a way that the amount of recording layer or insulating layer formed is 4 to 5 g / m ² after drying.

The recording material produced in the manner described has a white color and paper-like color Properties. Tests carried out with the recording material provide those which follow later Results given in the table.

Example 5

15 parts by weight of a polyvinyl acetate emulsion (solids content: 50%) and 20 parts by weight of clay are dispersed in 100 parts by weight of a 15% strength aqueous solution of a commercially available electrically conductive substance. The dispersion obtained is applied to both sides of a wood-free paper with a paper weight of 60 g / m ² carrier surface by means of a wire rail in such a way that the amount of electrically conductive layer after drying is 3 g / m ² carrier surface. The whole is then calendered, whereby an electrically conductive paper is obtained.

A 5% solution of 3-phenylsulfonaphthalene-b, 7-triazolo-2'-stilbene is also used (fluorescent brightener) in 100 parts by weight of a 15% vinyl acetate solution of a vinyl chloride / vinyl acetate copolymer (molar ratio of vinyl chloride / vinyl acetate = 87/13) registered. The final fluorescent brightener content is 3% by weight.

[The dispersion obtained is applied to one side of the electrically conductive paper in such a way that the amount of recording layer or insulating layer obtained after drying is about 5 g / m ^{2 of support} surface.

The recording material produced in the manner described has a white color and paper-like color Properties. Tests carried out with the recording material provide those which follow later Results given in the table.

Comparative example 1

An electrostatographic recording material is produced as in Example 1, but with the fluorescent brightener is omitted.

Comparative example 2

3 parts by weight of titanium dioxide are added to 100 parts by weight of a 15% solution of styrene in toluene, the whole being comminuted and mixed in a ball mill. The dispersion obtained is applied to the electrically conductive paper also used in Comparative Example 1 in such a way that the amount of the applied layer after drying is about 5 g / m ² .

Comparative example 3

15 parts by weight of titanium dioxide are introduced into 100 parts by weight of a 15% strength solution of styrene in toluene, whereupon the whole thing is comminuted in a ball mill and mixed. The dispersion obtained is applied to one side of the electrically conductive paper also used in Comparative Example 1 in such a way that the amount of the layer after drying is about 7 g / m ^{2 of support} surface.

Comparative example 4

15 parts by weight of titanium dioxide are in 100 parts by weight of a 15% aqueous solution of a commercially available electrically conductive substance entered, whereupon the whole thing in a homogenizer is thoroughly dispersed. The dispersion obtained

Tabel

is applied by means of a wire rail to both sides of a wood-free paper with a paper weight of 60 g / m ^{2 support} surface that the amount of the applied layer after drying is about 6 g / m ^{2 support} surface. After calendering, an electrically conductive paper is obtained. In order to produce an electrostatographic recording material according to Example 1, this is provided with an insulating layer.

Comparative example 5

Example 4 is repeated, but the fluorescent Brightener is omitted.

The ones with the various recording materials The results obtained according to the invention and comparative materials are shown in the following table:

Image density

contrast

Paper-like
properties

example 1 1.05 * Example 2 1.02 * Example 3 0.98 * Example 4 1.01 * Example 5 0.98 * Comparative example 1 1.06 (. Comparative example 2 0.97 -1 Comparative example 3 0.51 4 Comparative example 4 1.02 *

Comparative example 5

0.97

(the image background is yellow)

(the image background is yellow)

(feels like

coated paper)

(feels like

coated paper)

The image is recorded with the aid of a commercially available facsimile machine.

* = "Very good".

O = "good".

+ = "Not particularly good" and

X = "very bad".

The assessment is made with the naked eye.

Claims (1)

Patent claims: 1. Electrostatographic recording material made from an electrically conductive paper, from a 5th Paper and an electrically conductive layer, or from a paper that has an electrically conductive layer on both sides conductive layer is provided, as well as each with an insulating containing a plastic Layer which may contain a pigment, characterized in that it is in the paper, in the electrically conductive layer and / or an optical brightener in the insulating layer Formula: C-CH SOjNa Y ₁ where X, equal to the groups
-NH ₂ CH ₂ CH ₂ OH —N CH ₂ CH ₂ OH CH ₂ CH ₂ OH Vh ₂ CH ₂ OH
CH ₂ CH ₂ OH 'CH ₂ CH ₂ OH CH ₂ -CH ₂ -N O CH ₂ -CH ₂ - N - N i
\ CH ₂ -CH ₂ - NO CH ₂ -CH ₂ -NH- H) 20 (a) (b) 30th 35 (C) 40 M) (e) 45 50 55 60 65 (G) and Yi equal to the groups -NH SOjNa (C) (d) (e) (0 -NH (H) is, whereby only those groups designated by the same letters are contained in a compound to be allowed to; an optical brightener of the formula: O
X ₂ -C-NH SOjNa
where X ₂ equals the groups (2) OCH ₃ OCHj an optical brightener of the formula: NaSO ₃ - an optical brightener of the formula: -Nv (4) C-CH = CH-C an optical brightener of the formula: C ₂ H ₄ OH
and or
an optical brightener of the formula: NaO ₃ S (5)