CS210658B2 - Transfer-picture material - Google Patents

Abstract

1477799 Transfer sheets CARIBONUM Ltd 5 March 1976 [26 March 1975] 12609/75 Heading D2B A transfer sheet comprises a base sheet provided with a layer of porous material containing an ink within its pores, said porous material comprising a mixture of at least one cellulose ester and one or more acrylic resins in a ratio of 6:1 to 1:6 by weight. The base sheet may be paper or a plastics film, e.g. a polyester or polypropylene film. The cellulose ester may be cellulose acetate butyrate, or cellulose acetate propionate. The acrylic resin may be a poly(methyl methacrylate), poly- (ethyl methacrylate), poly(n-butyl methacrylate) or a copolymer of methyl and n-butyl methacrylates. The base sheet may be coated with a layer comprising polyurethane before application of the transfer layer. The ink may contain a colourless colour former or pigment(s).

Description

; The invention relates to a transfer material of the kind commonly referred to as carbon paper, and more particularly to the type referred to as coated solvent-based carbon paper. Such coated solvent-based carbon papers consist of a base sheet to which a layer of porous material is firmly attached, and the pores of the material comprise printing ink that is squeezed out of the porous layer by pressure, for example, caused by a writing instrument or type face of a typewriter. . Such coated solvent-based carbon papers are described, for example, in British Patent Specifications 382 220, 780 492 and 840 673. British Patent Specification 392 220 describes a porous coating having at least one cellulose ester as its main constituent, and British Patent Specifications 780 492 and No. 840,673 discloses porous coatings in which one component is a vinyl polymer. Other components have also been proposed for porous coatings, including acrylic resins, especially polymethyl methacrylate resins.

It is known that solvent-based carbon systems containing polymethylacrylate resins can be used to produce decal layers that provide copies of good readability but do not produce imprints when applied to non-printing pressures, such as when passing between typewriter cylinders, even if the surface of the layer has already been damaged by use.

However, such impression layers have two major drawbacks:

(a) The color release is such that only a limited number of copies can be made before the copy intensity becomes unacceptably low or uneven; and

b) the resin-containing layer of paint is characterized by poor adhesion, in particular to a base material such as polyester or polypropylene.

It is also known that solvent-based carbon systems, the main constituent of which are cellulose acetate butyrates resins, can form layers that are very easy to handle in use but which still provide copies of good intensity while maintaining a very good lifetime usage.

However, even these layers have their drawbacks, namely

(a) although their resistance to the smudging caused by the roller may be high, if used only to a limited extent, this resistance is lost after prolonged use;

(b) their odor is difficult to eliminate because it is largely, albeit not entirely, due to butyric acid contained in a resin, the main component of which is cellulose acetates and butyrates, and

c) The carbonaceous compositions on the bZz and solvent are characterized by an unstable viscosity having a pronounced tendency to increase upon aging, requiring a high percentage addition of expensive solvents, such as methyl ethyl ketone, to reduce their viscosity to a value suitable for coating.

The purpose of the invention is to provide an improved decal material of the type referred to as a solvent-based coated carbon paper.

It is another object of the present invention to provide coated carbon paper on. a solvent base suitable for a variety of uses.

It has been found that a solvent-based coated carbon paper can be obtained by using a mixture of at least one cellulose ester with at least one acrylic resin. In particular, it has been found that the use of a mixture of cellulose acetate and butyrates with acrylic resin can largely eliminate the drawbacks of the single resin component systems.

Accordingly, the present invention provides a transfer material comprising a backing sheet of polypropylene or polyester film, a layer of porous material and a color contained within the pores of the porous material, which transfer material is characterized in that the porous material comprises a mixture consisting of acetate and / or butyrate resins. % of cellulose with at least one methyl methacrylate resin having an average molecular weight in which the mixture of cellulose ester to acrylic resin is in the range from 6: 1 to 1: 6, based on the weight of the two components. '

Preferred ranges are from 3: 1 to 1: 3.

For handwriting or roller printing, a higher amount of cellulose acetate and cellulose butyrate resin is preferred, while a higher and relative amount of acrylic resin is desirable for typewriting or other impact strokes. ,

It has been found that a ratio of 1 part of cellulose acetate and butyrate based resin to 1 part of acrylic resin yields a coating suitable for both handwriting and typewriting. As a general rule, but with limitations, it has been found that by increasing the acrylic resin content, a higher transfer sharpness is achieved, but a shorter service life.

The transfer material according to the invention can be prepared according to the following examples:

Example 1

The porosity layer of the colorant coating is obtained from the following components:

Part. 1 (coloring agent)% by weight, parts of a practically non-drying vegetable oil (for example rapeseed, peanut or castor oil, or a mixture thereof10.5 vegetable lecithin1.0 carbon black (Raven 1255 Carbon Black) 6.4 Reflex Blue Toning Pigment 1, 0 diisobutyl phthalate1,0 toluene6,4

Part 2 (porous coating)% by weight, parts by weight of cellulose acetate and cellulose butyrates (equal proportions) 6,5 medium molecular weight polymethylmethacrylate resin (Elvaclte 2009) 6,5 methylethylketone51,1 ethyl acetate9,6

The above coloring agent (Part 1) is prepared by grinding the ingredients in a pebble mill for 16 hours. Then the mill is emptied.

The porous coating material (Part 2) is prepared by introducing the polymer-methyl methacrylic resin into a solvent under stirring, followed by stirring until the resin is dissolved. Also, cellulose acetate and butyrate resins are dissolved in the solvent, and this solution is then added with stirring to the solution of the polymeric acrylate resin. Then, the colorant material (part 1) is added to the porous coating material (part 2) and stirring is continued until a perfectly mixed mixture is obtained. The blend is then applied by any technique suitable for application to web paper (e.g., alternate roll-on and wipe-off technique) onto paper or polypropylene or polyester film, preferably provided with a polyurethane resin base coat as described below. This layer is suitable for writing. both with a typewriter and a pencil.

Example 2

A porous coating with a coloring agent is prepared from the following components:

Part 1% by weight, part practically non-drying vegetable oil (for example rapeseed, peanut or castor oil or a mixture of these oils) 11.1 ethoxylated aminoleate (Catafor 020) 0.5 carbon black (Raven 1255 Carbon Black) 6.7 carbon black ( Shelf SRF) 1,3 blue tint (Vlctoria Blue) -blue Viktoria0,3 diisobutylphthalate1,0 toluene10,9

Part 2% by weight of toluene resin based on cellulose acetate and butyrates (equal proportions) poly (methyl) (methyl) (acrylate) (ethyl acetate 2009) methyl ethyl ketone as solvent ethyl acetate as solvent

10.9

1.9

11.5

29.2

14.6

The above-mentioned part 1 is prepared by grinding said components in a sand mill for 16 hours, after which the contents of the mill are emptied into a container.

The above Part 2 is prepared by adding the polymethylmethacrylic resin to the solvent under stirring and stirring until the resin is dissolved. Similarly, cellulose acetate and butyrate resins are dissolved in the solvent, and the resulting solution is then added with stirring to the polymethyl methacrylate resin solution.

The mixture is then applied by means of an alternating roll-on and wiping technique on paper or a polypropylene or polyester film, preferably coated (preferably based on polyurethane, as described below).

This coating is suitable for typewriting.

Other compounds may be used in place of the cellulose acetate butyrate resin and the methyl methacrylate resin. Instead of cellulose acetate butyrate resins, cellulose acetate and cellulose propionates or other cellulose esters may be used. Furthermore, high molecular weight ethyl methacrylate, high molecular weight n-butyl methacrylate or low molecular weight methyl methacrylate-n-butyl methacrylate copolymer can be used as acrylic resins. Mixtures of cellulose esters and / or mixtures of acrylic resins may also be used.

It is also possible to add other pigments or other dyes which partially or completely replace the pigments mentioned in the previous examples. Similarly, suitable coloring agents may be used in conjunction with coloring agents (e.g., acidic compounds or electron acceptors) instead of pigments; when color developers are acted upon by the developers, the corresponding color is produced. It may be advantageous to apply a precoating layer to the base film. In this case, it is possible to apply a preliminary layer of this composition.

Pre-coat% by weight, part isocyanate resin (polyurethane, moisture-curing) (Daltosec 1350) 24.0 filler (Gasil 937) 1.3 pigmented micro-cellulose pulp (Dispercel Chips 33/2019) 6.0 ethyl acetate (grade ,, P ") As a solvent 68.7

The pre-layer is then applied to the substrate (paper or foil) by gravure printing.

If desired, the pulp of pigmented nitrocellulose can be replaced with the same amount of nitrocellulose pulp (PGHX 30-50 20% DBP).

Claims (1)

SUBJECT An imprinting material comprising a polypropylene or polyester backing sheet, a layer of porous material and a color contained within the pores of the porous material, characterized in that the porous material comprises a mixture consisting of a resin based on inventive cellulose acetate and / or butyrates with at least one methyl methacrylate. a medium molecular weight resin in which the ratio of cellulose ester to acrylic resin is in the range of 6: 1 to 1: 6, based on the weight of the two components.