CS242254B1 - Fulie for negative image engraving - Google Patents

Abstract

The invention addresses the composition and methods of production of a film for creating a negative image by engraving. A layer of a polyamide-type polymer material is applied to a transparent film substrate, colored or pigmented to the desired degree of optical density for actinic or other light sources. Films for creating a negative image by engraving are used in cartography, printing, electrical engineering, etc.

Description

The invention relates to a foil with a perforable opaque or semi-transparent colored layer, which is used for creating negative line images, especially in cartography, printing, electrical engineering and other fields.

Films for creating a negative image by etching usually consist of a substrate consisting of a clear film with suitable mechanical, physico-chemical and optical properties, and an engraving opaque or semi-transparent colored layer opaque to actinic light or light of a defined wavelength, or several sandwich layers for selective filtration of the light flux during copying.

The substrate is usually made of polyethylene terephthalate, polyethylene, polypropylene, polystyrene, polyvinyl chloride or cellulose triacetate, glass and the like. The engraving layers were originally based on natural colloids and wax, mixtures of various waxes and polyvinyl alcohol and pigments for coloring the layers. These wax layers were used on a substrate of cellulose triacetate, polyvinyl chloride, polystyrene and others.

Later, engraving layers based on polyesters (alkyd, cellulose derivatives, chlorinated polyvinyl chloride or its copolymers with polyvinyl acetal and polyvinylidene chloride) were developed. These layers were used mainly on polyester and polyolefin substrates, preferably on polyethylene terephthalate foil with a thickness of 0.05 to 0.18 mm.

While the original wax layers were quite soft (risk of mechanical damage to the engraving), other types of engraving layers, on the contrary, showed excessive hardness and brittleness caused not only by the chemical base of the macromolecular substance, but also by the pigments and especially fillers used.

To achieve high thixotropy and high volume concentrations of pigments and fillers in the engraving layer, which is also necessary to achieve the required degree of cohesion and adhesion of the layer for engraving, the engraving layers were filled mainly with finely dispersed silicon and magnesium oxides with ^a high active surface area for binding the binder.

The hardness, brittleness of engraving layers, contamination of the image with small fragments of the layer, and significant wear of working tools due to the high concentration of silicon dioxide in the layer are the basic shortcomings of current engraving layers.

The above-mentioned shortcomings are eliminated by a film for the formation of negative images by engraving, consisting of a transparent substrate and an engraving layer, characterized in that the engraving layer contains polymeric amides of monomeric or dimeric fatty acids with bifunctional or multifunctional aliphatic or aromatic-aliphatic amines, wherein the polyamide engraving layer in dry matter contains 5 to 95% polyamides, further >0.05 to 65% of dyes, pigments and, fillers and not more than 10% of medical additives and plasticizers, such as silicone oil, polyethylene wax or dibutyl phthalate.

The invention also relates to a transparent substrate, which is formed of a biaxially oriented polyethylene terephthalate film, polypropylene or polyolefin film with a transparency of at least 10%, onto which coating materials are applied as colored coatings by spraying, pouring, rolling or dipping.

A new type of polyamide-based etching layers has now been found which can be used for some of the above-mentioned substrates and which do not have the disadvantages of the layers currently produced. They are, in particular, polyamides obtained by reacting diamines with dimeric fatty acids of soybean or linseed oil.

The highly thixotropic properties of these substances are explained by the formation of hydrogen bridges between the hydrogen of the amide group of one chain and the oxygen of the carboxyl group of the other chain.

HO—1 C—Ri—Ri—C—řl—CHz—CHž—N ] _x —H

II II I I

OH H

HO

I II II

Η— [N—ÍJH2-CH2—iN—C-Ra— Rz— C ] _x —OH

H

The advantage of the film according to the invention is that, based on these properties, it is not necessary to create a thixotropic structure of the coating and layer with high additions of fillers, especially silicon dioxide, but it is sufficient to create a volume concentration of pigments corresponding to paints and enamels to achieve the desired opacity of the layer.

Films for creating negative images by engraving consist of a polyester or polyolefinic substrate, preferably a polyethylene terephthalate film, provided with a single coating of an engraving layer with a thickness of 0.010 mm. This engraving layer is based on thixotropic polyamide resins such as, for example, condensation products of ethylenediamine or diethylenetriamine with dimers of fatty acids of linseed or soybean oil and ethylenediamine, diethylenetriamine with linseed oil.

These polyamide resins are dissolved in alcohols or mixtures of alcohols and aliphatic or aromatic hydrocarbons. Pigments are finely dispersed in the binders thus prepared, which impart the desired color and opacity to the engraving layer.

Finally, the coating material is diluted to the desired consistency and applied to the foil or other substrate by spraying, pouring, dipping, or rolling. The layer dries quickly and after drying the foil is ready for use.

During continuous film production, it is possible to dry the engraving layer in a drying tunnel at slightly elevated temperatures to avoid defects from rapid evaporation of solvents ("pinholing").

A negative image is easier to make on this foil because the engraving virus is of medium hardness and, due to the physical and chemical properties of the layer, an integral bond is created during engraving, which is easier to remove from the surface before phototechnical or photomechanical copying.

The reduced proportion of fillers and especially the non-use of silicon dioxide also have a positive effect on both the quality of the negative image and the quality of the working tools.

Example 1

Under the dissolver, the polymer condensate of ethylenediamine -with a dimer of limolic acid and oleic acid -with an amine number of -m-max. 7, -acid number of max. 6.5 is dissolved in a mixture of propanol and technical gasoline in a ratio of 1:1. After dissolution, titanium white, Versal blue and Versal yellow are added.

After homogenization, the mixture is dispersed in a pearl or ball mill with an optimum grinding fineness of up to 0.005 mm. The layered mass is further diluted with solvents to the desired consistency and applied using the dipping principle at a constant speed of movement of the polyethylene terephthalate film strip and to the required thickness of 0.050 to 0.1-80 mm.

After drying in a drying tunnel at a maximum temperature of up to 50 °C, a film for creating negative images by engraving with an optimal engraving layer thickness of 0.010 mm is obtained.

Composition of the substance:

polymer condensate of ethylene-6 diamine with ethylene-6 diamine

acids and oleic acids 2.25 grams technical gasoline 750g propanol (isopropanol) 750g capital yellow 15 grams capital blue 15 grams titanium dioxide 155g Example 2

The coating material is prepared by the same procedure as in the previous example. A polyethylene foil with a thickness of 0.075 mm is sprayed with a crown charge before coating. Then the sheet is placed on a flat surface and the layer is applied manually with a rod spatula (squeegee) so that the dry weight is 0.010 mm. After drying, the foil is ready for creating a negative image by engraving using special hand engraving tools. Composition of the material:

polymer condensate of diethylenediamine with acid dimers

IfnoT and lino-linen 250 e-ethanol 1,200 -toluene' 400 capital yellow 125 v-erzálová -blue 250

Example 3

Use of directly dyed polyamide chips for the preparation of dispersion material.

The coating material is prepared in a similar manner as in the previous cases. The material is poured into a narrow cuvette and the polypropylene foil formats with a thickness of 0.050 mm are clamped onto the support plate. Then, by dipping, 2 formats are coated simultaneously, which corresponds to a dry layer of 0.010 mm. After slow drying, the foil is left to dry in a drying oven at a slightly elevated temperature of 40 to 50 °C. The foils are then ready for use for creating a negative image by engraving.

Composition of the substance:

polyamide chip green 350 g titanium dioxide. 150 g isopropanol 750 g technical gasoline 750 g

Claims (2)

SUBJECT An engraving film comprising a transparent backing and an engraving layer, characterized in that the engraving layer comprises polymeric amides of monomeric or linear fatty acids with bifunctional or multifunctional aliphatic or aromatic-aliphatic amines, wherein the polyamide engraving layer in the dry matter comprises 5 to 95 % of ipolyamides, as well as 0.05 to 65% of dyes, pigments and fillers, and at most 10%, cocoa additives and plasticizers, such as e.g. INVENTION silicone oil, polyethylene wax or diibutyl phthalate. 2. A film according to claim 1, wherein the backing is a biaxially oriented polyethylene terephthalate film, polyethylene terephthalate film, polypropylene film, polyolefinic film of at least 60% transparency, on which the coating materials are stretched as a paint, by spraying, spraying, pouring, dipping. Severografla, n. P., Plant 7, Most Price 2,40 Kčs