FI97286B - Multilayer, flexible transfer belt - Google Patents

Description

97286

The present invention relates to a multilayer, flexible transfer tape or tape having a carrier layer and a contact adhesive layer, and between said carrier layer and the contact adhesive layer, a binder-containing transfer layer having a higher adhesion to the contact adhesive rock is interposed.

Several possibilities are known for using pigmented, liquid systems to cover typos. Thus, for office use, brush-white pigmented dispersions containing a highly volatile organic solvent are applied to correct typewriters or the like. However, the evaporation of a highly volatile solvent is harmful to the environment. Evaporation must stop for a relatively long time before overwriting is possible. When applying the repair dispersion with a brush, a uniform coating is usually not obtained.

A better repair performance is made possible by DE-OS 2 626 891, which describes a multilayer, flexible transfer sheet formed from a carrier sheet coated with an adhesive separating layer, a polyvinyl alcohol-bonded transfer layer and a thin adhesive coating. The transfer layer also contains titanium white as a pigment. After removal of the carrier sheet, the transfer layer acts as a correction coating for incorrect typewriters. There is no mention in the patent of a tamper in a hand-held transfer roller, such as is used hereinafter in connection with the present invention, and as experiments have shown, the method according to its patent does not lead to the desired tearing of the repair coating.

The problem addressed in the present invention is to develop the above-mentioned transfer tape so that the movable coating containing the binder 35 can be cleanly and accurately attached to the areas to be covered, and the use of a hand-held device allows simple, quick and even attachment to the substrate.

The problem is solved according to the invention in that the binder-containing transfer layer contains 0.5 to 5% by weight of a soluble cellulose derivative which acts as a release aid.

The carrier layer of the flexible transfer tape according to the invention consists of a similar plastic film used in connection with typewriter ribbons, e.g. polyethylene terephthalate, polypropylene, polyethylene, polyvinyl chloride or polycarbonate. Silicone-coated paper is also suitable as a carrier substrate. The silicone coating can also be replaced with another anti-adhesive such as, for example, polytetrafluoroethylene.

The thickness of the carrier layer is preferably about 10 to 60, in particular 15 to 55, the thickness of the surface layer is about 5 to 40, in particular about 15 to 25, and the thickness of the contact air layer is about 1 to 8, in particular about 20 to 5. pm. In order to optimize the transfer tape according to the invention, it is expedient to select a thickness ratio for the contact adhesive layer and the transfer coating of about 1: 4 to 1:12, in particular about 1: 8 to 1:10.

The contact adhesive layer may contain commercial adhesives. 25 moja. They are materials based on elastic and fully adhesive self-adhesive masses with high adhesion forces and which adhere immediately to various surfaces at limited pressure and ambient temperature. They are preferably applied as an aqueous solution 30 to a transfer coating already placed on the support substrate, since the binder-containing transfer coating already formed in this way does not redissolve. Among these types of contact adhesives, those based on acrylate are particularly preferred. The starting materials can be viscous solutions or dispersions based on rubber, polyacrylates, polyvinyl ethers or polyvinyl isobutyl. Preference is given to polyacrylate-based materials. Suitable commercial products are Ucecryl 913R and Ucecryl PC80 (sold by UCB, Ammelicht, 5 Belgium) as well as plastic dispersion VP 859/6 (sold by Frei-Hoff). The preferred contact adhesive, evenly distributed in the aqueous medium, contains wetting agents and surfactants (sold under the trade name Byk W). Said solutions or dispersions of contact adhesives are used to form the contact adhesive layer in an amount of preferably about 1-5 g / m 2 and particularly preferably about 2-4 g / m 2 for the transfer coating.

In the formation of a binder-containing transfer coating, the use of thermoplastic or thermoelastic polymers in the form of a solution or dispersion is preferred. In the field of the present invention, the following substances can be advantageously used to solve the given problem: a) Polyurethanes with a molecular weight of 15,000 to 50,000, e.g. Stahl-Chemien Permuthane U4924 or Bayer 20 AG's Desmolac 2100, b) linear, saturated polyesters with a molecular weight is 20,000 to 30,000 e.g. Goodyear Tire & Rubber's Vitel PE 307, c) styrene-isopropylene-styrene copolymers,. 25 e.g. Shell-Chemien Cariflex TR 1107, d) acrylates and methacrylates, e.g. Pexigum 7 H from Roehm GmbH, e) diphenylcarboxylic acid modified polyamides, cf. Rhone-Poulenc's Scope 30 or Emery Chemicals' Emerez 30 1533, f) polymer dispersions based on vinyl propionate, e.g. BASF's Propiofan 6 D, g) water-soluble polymethacrylate containing a carboxymethyl group, e.g. Rohagit SD15 from Roehm GmbH.

97286 4 This list is not claimed to be exhaustive and does not impose any restrictions on selection. In fact, it will be apparent to one skilled in the art that other binders may be used, especially since the nature of the binder is not a matter for the present invention.

In order to achieve an optimal embodiment of the present invention, in selecting the particular binder to be used in forming the movable coating, attention must be paid to the plasticizer used. A plasticizer should be used which, when applied to the surface to be repaired or covered, does not normally penetrate a thin layer of contact adhesive and does not come into contact with or interfere with the area to be repaired or the dyes contained therein, resulting in dyeing of the transfer coating. It has been found that standard plasticizers such as silicone, castor and mineral oils are suitable. Other plasticizers, which are preferably used in other fields, such as phthalates or oleic alcohol, are less suitable. In the borderline case, the adverse effect of the plasticizer can be counteracted by incorporating into the binder-containing transfer coating a so-called "varnish" which precipitates or insolubles the transferable colorant so that it does not migrate to or stain the attached transfer coating. Suitable varnishes are tannin and tannin derivatives. It is generally possible to use varnishes of known types from inks and inks. They are preferably present in the binder-containing transfer coating in an amount of about 0.5 to 5% by weight, in particular 1.5 to 3.5% by weight. Particular preference is given to about 2-2.5% by weight.

During the preparation of the transfer tape according to the present invention, the binder selected for forming the transfer coating is preferably brought into solution form, or if it is a polymer dispersion, it is used as a dispersion. The choice of solvent depends on the nature of the binder used. Preference is given to low to medium boiling organic solvents from the group consisting of alcohols such as ethanol, isopropanol and butanol, ketones such as acetone and methyl ethyl ketone, esters such as ethyl and methyl acetate, aromatic hydrocarbons such as toluene, aliphatic such as benzenes, in the boiling range of 70 to 140 ° C, alone or in mixtures, as well as water, alone or in a mixture with low-boiling, water-soluble organic solvents. The concentration of binder in the solution or dispersion is not essential to this invention. As a rough guide, a range of about 3-15% by weight may be considered, with a range of about 4-10% by weight being preferred. In forming the transfer coating, said solution or dispersion is preferably applied to the support substrate in an amount of 15 to 25 g / m 2 and particularly preferably 18 to 22 g / m 2.

In the context of the present invention, the term "colorant" is to be understood in a broad sense and forms the collective term for all colorants, including dyes and pigments, the latter also having the property of a filler. Dyes are understood to mean those colorants which are soluble in water, organic solvents or binders, as opposed to insoluble pigments. The color may be immediate, or it may also be manifested through fluorescence. The latter occurs, for example, in the case of fluorescent luminescent dyes. If the transfer tape of the present invention is used to correct typewriters, pictorial representations or the like, the binder-containing transfer coating more specifically contains white pigments such as titanium white, crystalline chalk, alumina or colloidal silicic acids. If the transfer coating is dyed, inorganic pigments such as chromium gel, ocher, iron oxide red, cobalt blue, uit-97286 6 ramarine blue and anthracone blue as well as organic pigments such as alkali blue, phthalocyanines, azalines, phthalocyanines, rautaoksidimustaa. Examples of 5 fluorescent dyes are Dayglon Blaze Orange T 15, Ciba Geigy's Maxilonbrillant Flavin 10 GFF, Bayer AG's Pyran and BASF's Basonyl-Rot 540.

The optimum control of the covering operation 10 of the transfer tape according to the present invention, in particular the binder-containing transfer coating, can be effected by means of the pigment content. The optimum pigment content depends on several factors, such as the nature of the binder chosen, the pigment itself and the additives used. A specific critical amount range cannot be given. As a rough guide, the binder / pig-15 ratio is about 1: 1 to 1:12 by weight, especially 1: 3 to 1: 8 and more particularly about 1: 4 to 1: 7.

An essential component of the binder-containing transfer coating of the transfer tape of this invention is a "release aid". Only the use of such a release aid ensures that, when attached to the transfer coating base, clean release occurs under tensile stress conditions. Surprisingly, it has been found that a relatively limited group of compounds have the desired properties as release aids according to the present invention, namely soluble cellulose derivatives. Particularly preferred cellulose derivatives are cellulose ethers which are soluble in organic solvents and / or water, such as methyl, ethyl, hydroxyethyl, ethylhydroxyethyl and carboxymethylcelluloses, and cellulose esters, such as cellulose acetate, propionate and acetobutyrate. However, several other soluble cellulose derivatives are also suitable and provide the desired effects. It will be appreciated that the basic structure of the cellulose in the soluble cellulose derivative is important, while the groups disclosed, such as the ethyl group, etc., cause the derivative formed to dissolve in the particular solvent selected.

The amount of release aid used in the transfer coating is not critical, but depends on the nature of the binder, pigment and additives used. The preferred amount is about 0.5 to 5% by weight, especially about 1.5 to 3.5% by weight. These proportions refer to dry matter. The ratio of the amount of release aid to the amount of binder can also be used as a basis for forming the transfer coating. As a rough guide, the ratio of release agent to binder could be about 1: 2 to 1:20, most preferably about 1: 4 to 1:10.

Other additives may be added to adjust the properties of the attachment method and the transfer coating attached to the substrate. These may in particular be coating-enhancing agents, such as, in particular, aluminosilicate, colorants, such as carbon black, or the aforementioned varnishes, in particular basic dyes, e.g. in the form of gallic acid derivatives, such as, for example, Ciba Geigy Print.

The aforementioned materials of the individual layers of the transfer tape according to the present invention generally satisfy the basic requirement that the adhesive stress (defined by adhesion work according to the Dupren equation, cf. KL Wolf "Physik und Chemie der Grenzflächen", 5 25 Springer Verlag 1957, p. 164) is greater than between the carrier tape and the transfer coating. If this is not the case, a suitable anti-adhesive must be added to the carrier tape to meet this basic requirement.

30 In such cases, the additional requirement that the transfer coating formed on the substrate be non-adhesive to other materials, in particular paper, with which it comes into contact is regularly complied with. Thus, the adhesion stress conditions set forth below may result in the successful use of the transfer tape 97286 8 of the present invention, where the symbol "S" indicates the adhesion stress ratio between different materials, i.e., S1 paper / contact adhesive layer, S2 transfer coating / contact adhesive layer, S3 transfer adhesive layer, S3 / carrier tape, S4 transfer coating / paper, and S5 5 contact adhesive layer / carrier tape, and the following requirements are met: Sx greater than S3, S2 greater than S3, S5 much smaller than S2, and S5 less than S3. In addition, the free surface of the transfer coating attached to the substrate, especially the paper, should not have an adhesion power outward-10, i.e., S4 is then zero or approaching zero. In other words, the attached transfer coating should not stick when touched by hand or paper.

The preferred transfer tape manufacturing method of the present invention is characterized in that a suitable plastic solution containing the aforementioned release aid is applied by a conventional application technique, e.g. a scraper, to a carrier substrate in the form of a flexible film, the solvent is evaporated by raising the temperature, then an aqueous dispersion containing a contact-20 adhesive for a binder-containing transfer coating formed by a conventional application technique such as a scraper or a roll coater, and then the water is evaporated off.

When using the transfer tape according to the present invention, it is preferable to use commercial fasteners in which the transfer of the contact adhesive-coated transfer coating from the spool takes place by simultaneously pulling the carrier tape. This results in a particularly easy handling of the transfer belt according to the present invention. This can be based on hand-held devices in the commercial area. A particularly suitable device of this type is a so-called hand roll with a feed roll having a transfer belt placed in a suitable housing from which the belt is led out to a transfer foot which protrudes from the housing and from said foot returns to the housing on the collecting roll. Proper transmission between the coils in the housing 9 97286 ensures that the transfer belt is always sufficiently tight. To use the transfer tape, the user takes the housing in his hand and uses a transfer foot to press the outer (detachable) coating tape coming over the end edge 5 against the substrate to which it is to be transferred (e.g. on a printed sheet of paper for repairs). During printing, the user moves the device relative to the substrate and thus transfers, e.g., a covering or fluorescent coating to the substrate, with the flexible carrier layer rewinding 10 out of the feed roll and back to the collection roll.

The transfer tape of this invention is particularly suitable for use as a repair agent in the office, school, and home for the purpose of covering up misspelled typewriters, markings, drawings, and engravings. Another use for the transfer tape may be the color marking of surfaces, documents and / or signs, in which case the transfer tape contains a transfer coating with a colored pigment. One way to use it is to highlight text, characters, or pictograms. For this purpose, the transfer coating 20 is preferably transparent and dyed in daylight with a fluorescent dye. In all the use examples mentioned here, it is particularly advantageous that the application takes place "dry", i.e. there is no staining of the liquid coatings and no evaporation of the abhorrent solvents, so that immediate overwriting is possible. Thus, the transfer tape according to the present invention allows, for example, easy, rapid and even application of covering coatings, in particular those containing colorants, to substrates. If the transfer coating of the transfer tape 30 according to the present invention is transparent, i.e. it does not contain e.g. opaque pigments, then it can be used for mere protection without dyeing effect, as well as for preserving and protecting writing characters that would otherwise be sensitive to air or the like.

97286 10

The invention will now be described in more detail by way of examples.

Example 1

Initially, the following dispersion is prepared to form a dye-containing transfer-5 coating: (po. = Parts by weight)

Solvent-soluble polyurethane (Permuthane U 4924) (25% isopropanol / toluene, mixing ratio 1: 1) 19.0 po.

10 Isopropanol 10.0 po.

Toluene 35.0 po.

Stop (Printan G) 1.0 po.

Ethylcellulose N7 (cleavage aid) 1.0 po.

Titanium dioxide (Kronos RN34) 29.0 po.

15 Aluminosilicate P820 (coverage enhancer) 5.0 po.

Carbon black (Printex 140 V) (dye) 0.01 po 100, 01 po

The above coating material was applied with a scraper 18 in an amount of 20 g / m 2 on a silicone paper substrate. The solvent was then evaporated at about 100 ° C using hot air. Using a scraper, an aqueous dispersion with the following ingredients was then applied to the surface of the dye-containing coating: Acrylate-based contact adhesive (Freihoff plastic dispersion VP 859/6) (acrylic-based copolymer) 66.9 po.

Water 33.0 po.

Wetting agent or surfactant (Byk W) 0.1 po.

30 100.0 po.

The contact adhesive was applied with a scraper with a thickness of 2 g / m 2. The aqueous fraction was then evaporated at about 100 ° C with hot air.

The resulting transfer tape was particularly suitable for covering typewriter characters on paper. It quickly gave: »· IIM I M <I I r * i 97286 11 and a uniformly attached cover tape on which it was possible to rewrite directly. The fastening took place with a commercial hand roller.

Example 2 Example 1 was formulated using the following composition to form a dye-containing transfer coating:

Polyurethane (Desmolac 2100 from Bayer AG) 5.0 po.

Methyl ethyl ketone 30.0 po.

10 Toluene 28.6 po.

Maxilonbrillantflavin 10 GFF (BASF) 1.0 po.

Basonyl-Rot 540 (BASF) 0.4 po.

Titanium dioxide (Kronos RN 34) 29.0 po.

Aluminosilicate P 820 (Degussa) 5.0 po.

15 Ethylcellulose N7 (Hercules) 1.0 po.

The transfer coating of the resulting transfer tape had good coverage, was colored (orange), and did not fluoresce.

Example 3 Example 1 was formulated using the following composition to form a dye-containing transfer coating:

Linear saturated polyester (Vitel PE 700 - Goodyear) 4.0 po.

25 Methyl ethyl ketone 30.0 po.

Toluene 31.0 po.

White pigment, zinc sulphide (Sachtolith L - Sachtleben GmbH) 25.0 po.

Ethylcellulose N7 (Hercules) 1.0 po.

30 Blaze Orange T 15 (Dayglo) 9.0 po.

The transfer coating of the resulting transfer tape had good opacity, was colored (orange), and fluorescent.

97286 12

Example 4

Example 1 was formulated using the following composition to form a dye-containing transfer coating: 5 styrene-isoprene-styrene copolymer (Cariflex TR 1107 - Shell) 4.7 po.

My methyl ethyl chain 42.0 po.

Toluene 42.0 po.

Redglo Soluble Toner GF 13 (Redglo) 0.8 po.

10 Ethylcellulose N 22 (Hercules) 1.0 po.

Aluminum stearate Alugel TH 34 (Bärlocher) 8.0 po.

Silicic acid (Aerosil 200 - Degussa) 1.0 po.

The transfer coating of the obtained transfer tape was transparent and colored (orange).

15 Example 5

Example 1 was formulated using the following composition to form a dye-containing transfer coating:

Vinyl propionate-based polymer dispersion 20 (Propionfan 6D - BASF) 20.0 po.

Titanium dioxide (Kronos RNCX) 30.0 po.

Aluminosilicate P 820 5.0 po.

Water 28.5 po.

Walocel MW 50 GB (Wolff & Co) 1.0 po.

25 Isopropanol 14.0 po.

Aqueous solution of silicone-free, halogenated organic compound (antifoam SF -Hoechst AG) 1.0 po.

Sodium dioctyl sulfosuccinate 30 (Lutensit ABO / wetting agent - BASF) 0.5 po.

The transfer coating of the resulting transfer tape had good coverage and was white.

11 Γ - Ettii JUU II! .

Claims (15)

1. A multilayer, flexible transfer belt with a carrier layer and a contact adhesive layer, wherein a binder-containing transfer layer lies between the carrier layer and the contact adhesive layer, and the transfer layer has greater adhesion to the contact adhesive layer than ρά the carrier layer, characterized in that it binds to the adhesive layer. % by weight of a soluble cellulose derivative as a tear aid. Transfer belt according to claim 1, characterized in that the cellulose derivative is ethyl cellulose. Transfer belt according to claim 1 or 2, characterized in that the auxiliary carrier consists of plastic and / or silicone coated paper. Transfer belt according to any one of claims 1-3, characterized in that the transfer layer contains polyurethane as a binder. Transmission belt according to claim 4, characterized in that the polyurethane is an aliphatic monocomponent polyurethane. Transfer belt according to any one of claims 1-5, characterized in that the transfer layer 25 contains color-emitting substances. Transfer belt according to claim 6, characterized in that the color-emitting substance is a pigment. Transmission band according to claim 7, especially for use in correction, characterized in that the pigment is a white, overcoating pigment. Transfer belt according to claim 7, especially for use for marking characterized in that the pigment is an organic or inorganic colored pigment. A transmission band according to claim 6, especially for marking of characters and images, characterized in that the color-emitting substance is a fluorescent dye. Transfer belt according to any one of claims 1 - 10, characterized in that the transfer layer, when using a basic dye, contains lacquer for this purpose. Transfer belt according to any of claims 1 to 10, characterized in that the thickness ratio between the contact adhesive layer and the transfer layer is about 1: 4 - 1:12. Transfer belt according to claim 12, characterized in that the thickness ratio is about 1: 8 - 1:10. Process for producing a multilayer, flexible transfer belt according to any one of claims 1-13, characterized in that a plastic solution containing a tear-off aid in the form of a soluble cellulose derivative is applied with a conventional application technique. a flexible support layer, the solvent is evaporated through an increase in temperature, after which a water dispersion containing adhesive is applied, with a conventional application technique on the obtained transfer layer, and water is evaporated. Use of the transfer belt according to any of claims 1 to 13 in the form of a roller in a hand device. il: Utit lllfe!: · *: «'' <