CS199354B1 - Acceptor layer for carbonless directcopying papers - Google Patents

Description

The invention relates to an acceptor layer for carbonless direct-copy paper in which copies of the original record are made by a cell by handwriting or by typewriter, a line printer, line or dot recorder or other mechanical device or other physical device such as thermographic or light copiers .

The invention is concerned in more detail with layers where an image of the original is formed on the copy by the reaction of colorless compounds which, by large-scale contact with the active substances, produce a coloring of the chosen shade by chemical reaction.

The composition of these layers is such that the starting material has good chemical and physical properties, i.e. good adsorption capacity, high chemical reactivity, good mechanical resistance and high light reflectance.

Such an acceptor layer therefore comprises at least two substances, one of which ensures its chemical reactivity and the other of good physical properties.

Regarding the first substance, a number of substances are known which allow the formation of a colorant from colorless compounds used for direct-copy papers and which, according to their nature, can be divided into three groups, namely minerals, polymers and mixed substances.

The first group consists of acidic alumosilicates such as atapulgite, bentonite, montmorillonite, zeolites and kaolins, which do not, in themselves, guarantee good reactivity to the colorforming component, furthermore obstructed the light resistance and increase the copy intensity, which must therefore be costly selected and treated both chemically and mechanically,

199 3S4 also thermally.

The second group consists of organic substances, such as acidic polymeric materials, phenol-formaldehyde, phenyleldehyde and phenolacetylan resins, which are either directly in the paper stock or form an additional impregnation or are directly applied to the paper, where the latter is usually the most acceptable. Some of them are modified by some metals (Zn, Sn, Al, Na) in order to have higher reactivity compared to β by previous alumosilicates.

The third group consists of substances where they use alumosilicates vs mixtures and organic substances of phenolic type, sometimes also mixed with alkaline substances (for example soda, potash), but there is also a connection and metal salts.

The substances of the above groups have some disadvantages in terms of functional complexity or chemical activity, or in terms of technological difficulty or even less advantageous economics.

The above-mentioned disadvantages do not have an ecceptor layer for the carbonless direct-copy papers according to the invention, which consists of an adsorbent having a specific surface area of at least 150 m ² / g which is activated by at least one substance with one to three hundred active hydroxyl groups. and a coloring agent selected from the group consisting of phenols, polyphenols, phenolic polymers and polycondensates or polyhydric alcohols, optionally polymeric polyhydric alcohols, as well as a binder, pigments, plasticizers and pH adjusting agents.

Various types and modifications of silica, such as silica gel, amorphous silica produced by combustion of silanes, precipitated calcium silicate and diatomaceous earth are used as absorbents.

Phenols, polyphenols, phenolic polymers and polycondensates and polyhydric alcohols or polymers polyhydric alcohols are used as absorbent activators.

The activating agent is present in the layer in an amount of 0.01 to 10% by weight, based on the dry weight of the entire layer.

Polymeric substances, both natural and synthetic, such as gelatin, cleavage, starch, cellulose derivatives such as methylcellulose, carboxymethylcellulose, vinyl polymers such as polyvinyl alcohol, polyvinyl acetate, polyvinyl acetal, polyvinylcarbazole, polymethyl methacrylate, styrene with longer, are used as binders. or in the form of emulsions and suspensions ·

The acceptor layer according to the invention may further comprise directly a coloring agent embedded in the microcapsules or transferred therefrom from another layer. The release of the color-forming component can be carried out by mechanical or thermal means.

Some known compounds, such as leukoforms of triphenylmethane dyes, leukoforms of rosanilines, leucoanthraquinone dyes, fluoro derivatives, indoline derivatives, chromene and chromene derivatives, eplropyran derivatives, spiroindoline, xenthene or substituted phthalides, can be used as coloring agents.

In particular, the acceptor layers for the carbonless direct-copy papers of the invention have the following advantages:

they do not need to perform demanding physical activation like the acidic clay used hitherto, the color intensity per copy will be increased, the color component consumption will be reduced, the recording contrast per copy will increase, the dye formation rate will be increased.

The following are examples of the preparation of the acceptor layer according to the invention, wherein the individual components are given the following names: (1) active substance, (2) solvent, (3) adsorbant, (4) binder, (5) coloring agent, (6) a plasticizer.

Example 1

Three basic components are prepared separately: solution A - (1) 2,2- (4,4'-dihydroxydiphenyl) propane 5.25 WITH (2) acetone 100.0 ε suspension B - (3) silica gel (changes below 0.0005 mm) 50.0 ε (2) water 950.0 ε solution C - (4) polyvinyl alcohol 15.0 ε (2) water 50.0 ε

Solution A is mixed with suspension B and the mixture is heated with vigorous stirring until all acetone is distilled off. After cooling, solution C was added and the mixture was suspended in a bead mill.

The prepared suspension is applied to a paper of suitable weight and dried on it in a flow-through oven at a temperature of up to 105 ° C.

This results in a material with an acceptor layer which, in contact with another layer provided with a coloring component of the leuko-dye type, provides an instantly sharp, contrasting and readable copy under pressure.

Example 2

Prepare a suspension of the following components in an emulsifier or in a bead mill:

(2) water 1000.0 g (3) precipitated calcium silicate 100.0 g (4) carboxymethylcellulose 5.0 g (1) novolak (phenol polycondensate and 5.53 g formeldehyde)

The suspension thus prepared is applied again to the paper and dried thereon at a temperature of up to 105 ° C. The properties are similar to Example 1.

Example 3

Two basic components are prepared separately: suspension A - (2) water 1000.0 ₍ (1) 2-Naphthol 0.61 (3) Amorphous silica Ultrasil 80.0 (4) polyvinyl alcohol 10.0 suspension B - (2) water 500.0 (5) microcapsules with coloring agent 25.0 (4) polyvinyl alcohol 5,0

199 3S4

The suspensions A and B are mixed and the mixture is applied to a suitable grammage paper. The layer was used at a temperature of up to 50 ° C in an air-drying oven.

This results in a direct copying material which, at the pressure of the tip or die, already provides an image of the original, the color of which depends on the type of color-forming component used in the shape of the micro-shells.

Example 4

The components of the resulting suspension are prepared separately:

suspension A - (2) ethyl alcohol 800.0 g (3) amorphous silica (white carbon black) 110.0 g (1) n-octyl alcohol 2.0 g (1) 2,2- (4,4-dihydroxydiphenyl) propane 3.9 g (4) polyvinyl acetate 8.0 g suspension B - (2) water 200.0 g (5) microcapsules with color component 20.0 g (4) polyvinylcarbazole 2.5 g

The suspensions A and B are mixed and applied to the paper. The layer is dried in an air-drying oven at a temperature of up to 50 ° C.

A direct copying material of similar properties to Example 3 is formed.

Example 5

In a pearl mill, suspensions are prepared from the following components:

(2) water 1000,0 g (4) styrene acrylate copolymer SQKRAT 50,0 g (3) amorphous silica (white soot) 110.0 g (1) glycerine 2,0 g (1) 2,2- (4,4-dihydroxydiphenyl) propane 5.15 g (1) novolak 0.5 g

The suspension is loaded onto paper and treated in a flow-drying oven at a temperature of up to 105 ° C.

On contact with the color layer on a separate sheet, it gives a colored copy.

Example 6

It will prepare two basic components:

eložks A - (2) acetone · 50,0 g '(1) hydroquinone 1,82 g (1) glycol 0.5 g (1) novolak 1.5 g Component B - (2) chloroform 700.0 g (3) kieselguhr 120.0 g (4) polymethylmethacrylate 25,0 g (6) dioctyl phthalate 4.0 g

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The two components are mixed and suspended in a bead mill with efficient cooling. The resulting suspension is applied to a suitable paper or synthetic substrate which is an effective acceptor aid.

Claims (7)

SUBJECT OF THE INVENTION An acceptor layer for carbonless direct-copying paper, characterized in that it comprises an ebsorbent having a specific surface area of at least 150 m ² / g and which is activated by at least one substance having from one to three active hydroxyl groups selected from phenols, polyphenols, phenolic polymers and polycondensates, optionally polymeric polyhydric alcohols, and allowing and accelerating the formation of a colorant in contact with the colorant, as well as a binder, pigments, plasticizers and pH-adjusting agents. An acceptor layer according to claim 1, characterized in that it contains as an absorbent modifications of a silica such as Jeou silica gel, amorphous silica produced by combustion of thick, precipitated calcium silicate, diatomaceous earth. 3. Acceptor layer according to claim 1, characterized in that it contains absorbent activated phenols, polyphenols and phenolic polymers or polycondensates. 4. An acceptor layer according to claim 1, characterized in that it contains an adsorbent activated with polyhydric alcohols, optionally polymeric. polyhydric alcohols. 5. The acceptor layer according to claim 1, wherein the activating agent is present in the layer in an amount of 0.01 to 10% by weight, based on the dry weight of the entire layer. 6. The acceptor layer according to claim 1, wherein the binder comprises natural and synthetic polymeric substances such as gelatin, glue, starch, cellulose derivatives, for example methylcellulose, carboxymethylcellulose, further vinyl polymers such as polyvinyl alcohol, polyvinyl acetate, polyvinyl acetal, polyvinylcarbazole, polymethyl methacrylate and styrene. 7. An acceptor layer according to claim 1, characterized in that it comprises a color-forming component embedded in or transferred to the micro-casing from another layer.