EP1226958A1 - Image-receiving material having an adhesive layer, method for its' preparation, and its' use - Google Patents

Abstract

Printable image-recording material comprises a carrier sheet (3), at least one adhesive layer (2, 5), and an ink-receiving layer (1) containing a thermoplastic binder, where: (a) the ink-receiving layer includes a heat-activatable reactive polymer system; and/or (b) the binder is a heat-crosslinkable binder; and/or (c) the ink-receiving layer includes nanoparticles.

Description

The present invention relates to a material hereinafter referred to as the image recording system, the especially by means of transfer procedures. transfer technologies for digital data, especially pictures and Texts such as laser lettering and especially inkjet printers, is inscribable and printable. Such imaging systems can either be firmly attached to a carrier available or for transfer to substrates, especially dark textile substrates. Imaging systems, which are suitable for transfer to substrates are referred to below as transfer systems.

Transfer procedures or transfer technologies for digital data are subsequently called digital Image transfer process or digital image transfer technologies designated.

Imaging systems using transfer processes can be printed or labeled for digital data, are already known. Such imaging systems of the State of the art include a carrier, optionally can be provided with a layer which the Adhesion to a layer applied over it is reduced, an ink receptive layer and, if applicable, one arranged between the support and the ink-receiving layer, effecting the separation from the carrier or at least promoting layer. Such systems are described for example in US 5 501 901, US 5 242 739, EP-A-0 825 031, WO 98/30749 and EP-A-0 850 786.

Such prior art systems will be applied in such a way that they are on the ink-receptive layer side a substrate, especially a textile substrate, e.g. put on a t-shirt and warm it up with an iron be that between the substrate and the ink receptive layer better liability is developed than this between the ink-receiving layer and the carrier, such that that the carrier after the heat treatment and optionally at least partial cooling, removed by stripping can be.

These have prior art systems the disadvantage that they do take pictures on light substrates good quality, but not on dark substrates.

Furthermore, the systems of the prior art Technology has insufficient wash resistance in various applications on.

The aim of the present invention was therefore to to provide an imaging system that a improved color fastness, even after repeated washing, guaranteed and especially on dark substrates, gives good images, especially dark textile substrates.

This goal was achieved through the provision of an image recording system that a carrier, at least one ink receptive layer and at least one Includes adhesive layer, the ink-receiving layer a thermoplastic binder and one under the influence of heat reactive polymer system and / or a thermoplastic, crosslinking under the influence of heat Binder and / or a thermoplastic system and Contains nanoparticles.

Surprisingly, it was found that a such material according to the invention on the one hand has good ink absorption capacity and on the other hand, as a result the reactive polymer system and / or the nanoparticles, the ink is better integrated into the layer, thus the image quality and especially the durability is improved.

Figure 1 shows the structure of an inventive Imaging system with an adhesive layer, in particular an elastic adhesive layer and a removable carrier.

Figure 2 shows the structure of an inventive Image acquisition system with two layers of adhesion and removable carrier.

FIG. 3 shows an embodiment of the image recording system with a non-elastic resp. Not flexible intermediate layer and a non-removable Carrier.

Because especially in the presence of the reactive Polymer system the penetration of the ink receptive layer 1 is greatly reduced in the substrate is between the Carrier 3 and the ink-receiving layer 1 at least one another layer that improves adhesion (adhesion layer) 2, 5 available. The adhesive layer is common an intermediate layer 5 and / or an elastic Layer 2. Especially for application to textile, i.e. stretchable substrates, has an elastic intermediate layer 2 proved to be extremely advantageous because one such a layer is the transferred ink receiving layer 1 always back to the original dimensions brings and thus the appearance resp. the becoming visible unwanted cracks reduced or even completely prevented.

For application on dark substrates it - since the transfer processes do not provide white inks - highly preferred, the ink receptive layer 1 and / or at least one, preferably all, adhesion layers 2, 5 to pigment. Both the ink receiving layer are preferred 1 as well as the adhesive layers 2, 5 pigmented, to keep the pigment content in a range in which he does not have the desired properties of the layer impaired.

While of course the most diverse pigments can be provided, e.g. various colors, fluorescent Pigments etc. are white pigments, phosphorescent Pigments and effect pigments (e.g. mica pigments) prefers.

The ink receiving layer 1 can be a homogeneous Layer or from layers lying on top of each other be built up, possibly only a sub-layer Contains pigment, or being different sub-layers contain various pigments, e.g. one closer to the carrier partial layer lying one white pigment and another a sublayer removed from the support is a phosphorescent Pigment.

In one embodiment, the ink receptive layer comprises 1 in addition to a thermoplastic binder a reactive polymer system that can be activated under the influence of heat. Instead of a thermoplastic binder in Combination with an activatable reactive polymer system can also be a thermoplastic under the influence of heat crosslinkable binder can be used. Reactive polymer systems respectively. thermoplastic crosslinkable under the influence of heat Binder resp. Binder systems are known to the person skilled in the art and include prepolymers and hardeners, wherein the hardener and / or any catalysts present can be thermally activated. Because the imaging systems of the present invention usually are to be applicable without safety precautions are reactive polymer systems preferred that are not harmful to health Fabrics and preferably none uncomfortable smelling substances contain resp. in the reaction release.

Suitable systems include aminoplasts, in particular Melamine resins, such as melamine-formaldehyde resins, respectively. modified melamine resins, such as etherified melamine resins, Melamine-urea-formaldehyde resins resp. Melamine-phenol-formaldehyde resins. All of these resins have the advantage in the hardened state very stable and such translucent to be good image quality available is. Furthermore, their reaction by acid, e.g. diluted organic or inorganic acids or salts such acids, which become a volatile base only when heated (e.g. ammonia) split off, accelerated and the reaction can be controlled by the pH in this way. preferred Acids are p-toluenesulfonic acid, acetic acid and hydrochloric acid.

It is also possible to use melamine-formaldehyde resins instead Malamine resins with other aldehydes and / or ketones, which has the advantage that no formaldehyde can be released.

Alternative connections are, for example multifunctional aziridines, epoxies, and polyurethanes.

Suitable thermoplastic binders are known from the prior art (see US 5 501 901, US 5,242,739, EP-A-0 825 031, WO 98/30749 and EP-A-0 850 786).

Preferred binders, especially for Transfer systems include polyvinyl alcohols, polyvinyl acetates, Polyvinyl pyrrolidones, polyurethanes and specially preferably polyamides, for transfer to e.g. Cotton T-Shirts especially thermoplastics with melting point < 200 ° C, especially <140 ° C.

As a thermoplastic, crosslinking binder the above-mentioned come into question, with a corresponding one System one or more under the influence of heat for networking includes leading components.

So that the digitally applied image, for example a color image applied by means of laser or inkjet printing or lettering, is clearly depicted, ie shows a good resolution, it is advantageous if the ink-receiving layer comprises porous solid particles in a binder. Such porous particles are, for example, ceramic parts such as zeolites, silicates and aluminum hydroxides, or plastic particles, such particles being able to be obtained directly by a special production process or by subsequent treatment (mechanical or chemical) or agglomeration. Preferred porous particles are porous, solid thermoplastics. Such particles preferably have a specific surface area of> 6 m ² / g, in particular 20 20 m ² / g, a particle size of 0.1-40 μm, in particular 5-15 μm, and a melting temperature of <200 ° C. Thermoplastics such as the products known under the name Orgasol, in particular Orgasol® 3501 from, for example, Elf Atochem, Pouteaux, France, with a particle diameter of approximately 10 μm and a surface area of approximately 25 m ² / g are particularly preferred.

E.g. Ceramic particles used like Zeolite, these are preferably in combination with porous solid thermoplastics such as Orgasol® 3501.

In a further embodiment, the ink-receiving layer contains nanoparticles in addition to or as an alternative to reactive polymer components. Preferred nanoparticles have a specific surface area of 50 to 300 m ² / g and a dispersed particle size of 10 to 300 nm. Aluminum hydroxide (for example Dispersal from Condea Chemie GmbH, Fritz-Staigerstrasse 15, D-25541 Brünsbüttel) and silicates ( e.g. CAB-O-Sperse from Cabot Corporation, Cab-O-Sil Division, 700 EUS Highway 36, Tuscola, IL 61953-96-43). Such nanoparticles serve on the one hand as a pigment, on the other hand at the same time as porous particles for ink absorption. Surprisingly, it has been shown that such small particles remain in the layer even after repeated washing.

If the color absorption layer 1 from partial layers built up, with 2 partial layers preferred deep-melting porous particles are highly preferred, which become transparent when melted. Such porous particles can either only in one partial layer, preferably the sublayer without phosphorescent Pigment, or present in both sub-layers his.

The presence is for quick color absorption porous particles in the layer facing away from the support, the ink receptive layer 1, preferred.

Is additionally preferred (regardless of whether the ink receptive layer has a uniform structure or not), if not only the solid particles in the ink absorption layer, but also the thermoplastic binder are porous. Such increased porosity the local fluid intake, be it ink or pigment melt, increase, resulting in a better Penetration of the entire layer with pigment and clear Outlines. A process for making a porous Binder layer is e.g. known from EP 0 850 786.

The ink-receiving layer 1 usually has a proportion of thermoplastic binder of 5 to 40% by weight, preferably approximately 20% by weight, reactive polymer system of 8 to 20% by weight, preferably approximately 15% by weight, of porous particles from 5 to 80% by weight, preferably approximately 50% by weight, pigments from 5 to 80% by weight, in particular white pigment (TiO ₂ ) in quantities of 5 to 15% by weight, preferably approximately 10% by weight .-%, and / or phosphorescent pigment in amounts of 5 to 80 wt .-%, preferably about 65 wt .-%, based on the dried ink-receiving layer. In addition, small amounts of other customary components may also be present, such as a dispersing additive in an amount of about 0.2% by weight, for example "Coadis 123 K". Manufacturer Coatex, 35, rue Ampere-BP 8-ZI Lyon-Nord 69727 Genay Cedex-France.

When using a thermoplastic, crosslinkable Systems is usually in quantities of 10 to 60 wt .-% present, preferably in amounts of approx. 30 to 40% by weight.

A layer containing nanoparticles exhibits these usually in amounts of 40 to 80 wt .-%, preferably in amounts of approximately 60% by weight and the binder in amounts of 15 to 35% by weight, preferably in Amounts of approx. 25% by weight. In addition, other components can be present like porous particles, e.g. Orgasol 3501 in amounts of 5 to 25% by weight, preferably in an amount of about 15% by weight.

The ink-receiving layer is applied in amounts of (in the dried state) 5 to 80 g / m ² on the support provided with an adhesive layer.

The adhesion layer 2, 5 has a polymer matrix on, especially an elastic matrix. Suitable are all materials that have adequate adhesion between Ensure substrate and ink receptive layer and if necessary, additionally the desired elasticity respectively. Have flexibility. Such materials are e.g. Polyurethanes, such as polyester polyurethanes with a deep Melting range and high "Melt Flow Index".

As already mentioned above, the intermediate layer is preferably pigmented. An elastic adhesive layer usually has a thickness of 20-100 µm, in particular about 50 µm.

Although - as also mentioned above - The ink absorption layer and / or the intermediate layer contain various, identical or different pigments are white pigments and phosphorescent pigments and optionally effect pigments are highly preferred.

Suitable white pigments are widely used. The preferred white pigment is titanium dioxide, particularly preferably TiO ₂ with high relative scattering power, such as Kronos 1002, available from Kronos, International Inc., D-51373 Leverkusen.

Suitable as a phosphorescent pigment non-radioactive, long phosphorescent pigments, such as they e.g. in EP 0 622 440 = US 5,424,006 and e.g. by Nemoto (Europe) B.V. in Amsterdam NL at the name LumiNova® are available. Be used they usually in amounts of 5-80%, preferably in Amounts of approximately 65%. Such pigments phosphoresce in the generally at least 3 hours, often up to 8 hours.

The materials according to the invention include Transfer systems, e.g. for the transmission of images, i.e. at least the ink receptive layer, on a substrate. Such substrates are e.g. Fabrics, knitted fabrics, fleeces, especially textiles like T-shirts, but also others, especially "porous" substrates such as leather, wood etc., especially preferred dark substrates.

In addition to the preferred transfer layers include the materials according to the invention also "fixed" materials, i.e. Materials where the ink-receptive layer 1 remains on the carrier 3.

Fixed materials are relatively uncritical and can be a variety of different substrates , provided that their flexibility and the Liability of the ink absorption layer for the implementation of the Printing process is sufficient. To increase liability can optionally be a surface treatment of the carrier or an adhesion promoter layer between the carrier and the ink receptive layer can be provided. Also at fixed materials it can be useful to have an intermediate layer, in particular an elastic intermediate layer to apply, namely for example with a very flexible Carrier, such as a plastic or paper carrier, e.g. only bent when inserted into a holder and then stretched again. Due to the elastic intermediate layer any damage to the picture "healed" again by bending.

The ink absorption layer is also used for fixed materials 1 not further critical as long as it is sufficient Color recording, e.g. sufficient access to the porous solid particles, allowed and the ink after Warming well fixed.

Of course it is also within the framework this invention the printed resp. labeled ink absorption layer by applying a later Cover, e.g. a film, against mechanical damage secure, e.g. when used as signs, such as floor labels, Valve or keyboard names etc. For such applications it can also be beneficial be the carrier 3 on the one facing away from the ink-receiving layer Side with an adhesive layer 7, z. B. an adhesive layer, to be provided with a removable, optionally printed protective layer 8, like one-sided siliconized paper against pollution can be protected.

Other applications put under this Materials referred to as transfer materials advance, with at least the ink receptive layer and an adhesive layer on a substrate, e.g. a textile, is transmitted.

Such transfer materials must be in addition to the sufficient flexibility and sufficient liability the ink receptive layer 1 and the adhesive layer 2, 5 the carrier layer 3 during printing, respectively. inscribing also have good transfer properties, i.e. e.g. good strippability of the backing layer 3 before heat treatment. This separation of carrier and ink-receptive layer can e.g. through a release layer 4 between Backing layer 3 and adhesive layer 2, 5, e.g. a Silicone layer, caused or at least favored. This release layer can also be a pretreatment of the wearer.

The layers removed from the support become then with the one originally on the carrier or the release layer adhering layer applied to a substrate and afterwards, if necessary after covering the Surface (ink absorption layer) to protect against contamination by e.g. Iron on or hot laminate a substrate, e.g. a textile, fixed.

A carrier material 3, 4, 6 preferred for the transfer system is a siliconized paper on one side with a basis weight in the range of 50-150 g / m ² , which can be provided with a print 6 on the non-siliconized side.

A pigmented ink-receiving layer 1 can be produced simply by mixing powdered pigment with the other components of the ink-receiving layer or a partial layer of the ink-receiving layer 1 and solvent and the resulting mixture on an optionally pretreated or. pre-coated carrier is applied by conventional methods. Preferred solvents are water and alcohols, especially C ₁ -C ₃ alcohols.

The use of the materials of the present Invention is very versatile. But that is preferred Printing dark textiles, especially for their individual Layout. When using phosphorescent Materials you have the positive additional effect that by applying phosphorescent "white areas" in addition to that also with non-phosphorescent materials obtained aesthetic effect in a bright environment an aesthetic effect in the dark or e.g. in a Discotheque is achieved. At the same time, the carrier due to the phosphorescence in bad light better made visible what for its safety, e.g. as Pedestrians on poorly lit streets or paths, contributes.

The invention will now be illustrated by examples explained in more detail.

Examples: Example 1: Preparation of a Binder Solution for the Production of an Intake Layer (Reactive)

Polyamide, e.g. Elvamide 8023 (available from Du Pont de Nemours, International SA, 2, Chemin du Pavillon, CH-1218 Le Grand-Saconnex / Geneva), is dissolved in a mixture of water / methanol and microporous pigments (e.g. polyamide pigments such as Orgasol , with a grain size of approximately 10 µm and a specific surface area of approximately 25 m ² / g) are dispersed therein together with typical dispersing additives. Depending on the application, a white pigment (e.g. white pigment with a high relative scattering power of approx. 70, preferably titanium dioxide) or a phosphorescent pigment (e.g. a non-radioactive, phosphorescent pigment in powder form, e.g. Luminova G 300) is added and dispersed again by one to obtain good wetting of the pigments with the binder.

It then becomes a reactive polymer system (e.g. based on a melamine resin such as Maprenal MF 927) and a catalyst (e.g. an acid such as p-Toluenesulfonic acid (PTS)) added with stirring.

The concentration of the polyamide in the solution should be 10 to 90 wt .-% and the mixing ratio Water / alcohol is adjusted so that the Spreading the binder solution on a carrier and then drying at approx. 60 to 110 ° C a porous Layer arises.

Examples 2: Preparation of a binder solution for the ink-receiving layer (non-reactive)

Aluminum hydroxide (eg Dispersal 14/2 with a specific surface area of approx. 170 m ² / g and a particle size of 13 nm) are dispersed in water in a ratio of 20:80 until it appears to be dissolved. Then microporous pigments (eg Orgasol) are dispersed in amounts of approx. 15% by weight based on the solids together with typical dispersing additives. A binder (for example polyvinyl acetate such as Mowilite DM from Hoechst Aktiengesellschaft, Kennedyallee 76, D 6000 Frankfurt (Main) 70) is then added in an amount of approximately 20% by weight (based on the solids content).

Depending on the application, an additional White pigment or a phosphorescent pigment added and dispersed again for perfect wetting to obtain the pigments with the binder.

The solids concentration of the pigments (including the nanoparticle) to the binder approx. 2: 1.

With a mixture of water / alcohol (1: 1) the solution is adjusted so that when spreading the binder solution on a carrier and then Drying a porous layer at approx. 60 to 110 ° C arises.

Example 3: Production of an adhesive layer (elastic layer)

On a siliconized paper with a basis weight of approx. 100 g / m ² , either a thermoplastic, opaque layer with a basis weight of approx. 50 g / m ^{2 is} applied by means of an extrusion process or an ethylene-acrylic acid copolymer, for example an Enorex VN, by means of wet coating 375 (trade name of Collano Ebnöther AG, Rank industrial area, in CH-6203 Sempach station), with a solids content of approx. 40% by weight, such that the dry application is approx. 30 g / m ² .

Example 4: Production of a transfer film

In a first step, the coating solution prepared for the ink absorption layer (see Examples 1 and 2).

The viscosity is adjusted by dilution with water / alcohol so that the formulation, for example using a reverse roll coating process, is applied to the carrier film provided with an elastic layer (see Example 3 or available from Sarna Xirio AG, CH-3185 in Schmitten, under the trade name " PURO-X ") and can be dried at a temperature of 60 to 110 ° C. The dry application is approx. 30 g / m ² .

Such a layer has a good mechanical Stability and porosity and can be done with digital Image transfer processes, such as laser marking and especially ink-jet printers but also using CLP (Color Laser Printer) or CLC (Color Laser Copier), good print and label, but it can also be used with usual Painting aids such as aqueous and solvent-based Similar to crayons, water colors and wax crayons are painted like ordinary paper, and it leaves deal with common printing processes such as offset printing or print on screen printing.

The transfer to a substrate like white but also colorful and especially dark cotton T-shirts done with the iron at about 160 ° C to 200 ° C (heat setting for cotton). The reactive hot melt material is removed from the wearer, placed on the T-shirt and positioned at the desired location. The one from the substrate averted printed layer can e.g. by hanging up a non-stick film, such as a siliconized one Paper to be protected against pollution, before ironing under strong pressure is fixed on the substrate. Then several can Washing processes in a washing machine with common Detergents are carried out. The pigment and the Colors showed good fastness to washing.

Analogously, the transfer can also be carried out using a hot laminator on e.g. a large-area textile, e.g. on Banner, done.

Claims (19)

By means of printing techniques resp. Labeling techniques for digital data, in particular data of images and texts, printable and labelable image recording system with a carrier layer (3), at least one adhesion layer (2, 5) and a color recording layer (1), which contains a thermoplastic binder, characterized in that the color recording layer (1) also contains a thermally activatable reactive polymer system and / or that the thermoplastic binder is a binder that can be crosslinked under the influence of heat and / or that the ink-receiving layer contains nanoparticles. Image recording system according to claim 1, characterized in that the color recording layer (1) consists of a uniform layer. Image recording system according to claim 1, characterized in that the ink recording layer (1) consists of at least two and preferably two sub-layers. Image recording system according to one of claims 1 to 3, characterized in that the binder is porous. Image recording system according to one of claims 1 to 4, characterized in that at least one adhesive layer is an elastic intermediate layer (2), particularly preferably an elastic polyurethane intermediate layer. Image recording system according to one of Claims 1 to 5, characterized in that the color recording layer (1) and / or at least one adhesion layer (2, 5) are pigmented, in particular with white pigment and / or with phosphorescent pigment. Image recording system according to claim 6, characterized in that the white pigment is titanium dioxide. Image recording system according to claim 6 or 7, characterized in that the phosphorescent pigment is a non-radioactive pigment with at least 3 hours of phosphorescence. Image recording system according to one of claims 1 to 8, characterized in that the ink recording layer also contains porous solid particles, in particular porous solid particles with a particle size of 5-40 µm, preferably 5-15 µm, and a surface area of ≥ 20 m ² / g. Image recording system according to claim 9, characterized in that the porous solid particles are made of thermoplastic material. Image recording system according to claim 10, characterized in that the porous solid particles are made of polyamide, have an average diameter of approximately 10 µm and a surface area of 25 m ² / g. Image recording system according to one of claims 1 to 11, characterized in that it contains a reactive polymer system. Image recording system according to one of Claims 1 to 11, characterized in that the thermoplastic binder is a binder which can be crosslinked under the influence of heat. Image recording system according to one of claims 1 to 8, characterized in that the color layer contains nanoparticles with a specific surface area of 50 to 300 m ² / g and dispersed particle size of 10 to 300 nm. Image recording system according to claim 14, characterized in that the nanoparticles are selected from silicates and / or aluminum hydroxide. Method for producing an image recording system according to one of claims 1 to 15, characterized in that the constituents of the ink recording layer or a partial layer thereof are mixed and onto the carrier layer (3) provided with at least one adhesion layer (2, 5) and optionally a release layer (4). be applied. Using the imaging system after one of claims 1 to 15 for printing on substrates. Use according to claim 17, characterized in that the substrate is a woven, knitted or nonwoven, in particular a textile. Use according to claim 17 or 18, characterized in that the substrate is a dark substrate.

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