CS209181B1 - Transparent foil made from plastics for reprographic aims,fitted with electric conductive layer - Google Patents

Description

(54) Transparent plastic film for reprography, provided with an electrically conductive layer

BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to a transparent plastic film for the purpose of reprography, provided with an electrically conductive layer.

Transparent films of plastics for electroreprographic purposes, eg for the production of slides by electrographic technique, need to be provided with a conductive layer on the surface that creates a equipotential level and mediates the discharge of electrical charge to the edges connected to the grounded plate.

Until now, this object has been solved mostly by thin metal layers, optically semipermeable, formed by vacuum vapor deposition or cathode sputtering. Since these methods are technologically demanding and the semipermeable layer absorbs a considerable amount of light, there are efforts to create conductive, colorless, transparent layers of ionic conductive substances.

However, the results obtained so far are unsatisfactory since the conductivity of the ion-conducting substances is strongly dependent on the relative humidity of the air. Since the surface resistance must be around 1.10 ⁹ ohms per square, even at a relative humidity below 30%, the material requirements are high if the conductive layer is to perform its task.

These drawbacks are overcome by the transparent film according to the invention. SUMMARY OF THE INVENTION The present invention relates to a transparent plastic film for reprographic purposes, characterized in that it consists of a transparent plastic film itself provided with a layer of a compound of the general formula I

R-COO-CH ₂ CH (OH) CH ₂ -N

Ři

R ₂ wherein R represents an alkyl or alkenyl radical having 6 to 22 carbon atoms in the backbone,

R 1 = R ₂ denotes 2-hydroxyethyl in an amount of 0.005 g to 0.5 g / m ² ; preferably 0.01 g to 0.5 g / m ² , and a water-soluble polymer layer of formula II

CH ₂ = C (R) -COO 2 Z-OSO ₃ R ⁵ , II wherein R represents a methyl group,

Z is - C (R ¹ R ² ) -C (R ³ R ⁴ ) wherein R ¹ , R ² , R ³ , R ⁴ are hydrogen, and

R ⁵ denotes an alkali metal, i.e. sodium, in an amount of 0.1 g to 300 g / m ² , preferably 1 g to 10 g / m ^{2 of the} film.

The use of the first layer of the compound of formula I not only allows good physical adhesion of another water-soluble polymer layer to the plastic film, but has a significant effect on the resulting surface conductivity, especially in the region of very low relative humidity. Even at prelative humidity below 30%, a surface resistance of less than 1.10 ⁹ ohms was achieved without difficulty.

The compounds of formula I 3-bis (2-hydroxyethyl) amino-2-hydroxypropyl esters of fatty acids are novel and are prepared according to U.S. Pat. AO i 208966.

The compounds of formula II of the sodium salt of poly (2-sulfoxyethyl methacrylate) are anionic polyelectrolytes and are prepared according to A. O. 187 025.

Example

A 100% compound of formula (I) wherein R is an alkyl or alkenyl radical having 6-22 carbon atoms in the backbone, R 1 -R ₂ = CH ₂ -CH ₂ -OH at 0.025 g / m ² , was mechanically spread onto polyethylene terephthalate film, a layer consisting of a 15% solution of a water-soluble polymer of the formula II, i.e. a 15% aqueous solution of sodium 2-sulfoxyethyl polymethacrylate in an amount corresponding to 2 g / m ^{2 of} film after evaporation of water, was poured. After drying, the film had a conductivity of 8.10 ⁸ ohms / square at 28% relative humidity. ·

Claims (1)

SUBJECT OF THE INVENTION Transparent plastic film for electroreprography characterized in that it consists of its own transparent backed plastic film coated with a substance of the general formula 13 - bis (2-hydroxyethyl) amino-2-hydroxypropyl fatty acid esters R-COO-CH ₂ CH (OH) CH ₂ -N (I) wherein R represents an alkyl or alkenyl radical of 6 to 22 carbon atoms in the backbone, R = R ₂ represents 2-hydroxyethyl gaž0,5 0.005 g / m ^2, výhodou0,01 GAZ 0.5 g / m ^2, and a layer of water-soluble polymer of the formula II an alkali metal salt of poly (a2sulfoxyethylmethakrylátu) CH ₂ = C (R) -COO-Z-OSO ₃ R ⁵ , (II) wherein R represents a methyl group, Z is - C (R ¹ R ² ) —C (R ³ R ⁴ ) wherein R ¹ , R ² , R ³ , R ⁴ represent a hydrogen atom, and R ⁵ denotes an alkali metal, in particular sodium; in an amount of 0.1 g to 300 g / m ² , preferably 1 g to 10 g / m ^{2 of the} film.