WO2005015319A1

WO2005015319A1 - Toner

Info

Publication number: WO2005015319A1
Application number: PCT/EP2004/007963
Authority: WO
Inventors: Bernd Schultheis; Holger Köbrich; Harry Engelmann; Jose Zimmer
Original assignee: Schott Ag
Priority date: 2003-08-09
Filing date: 2004-07-16
Publication date: 2005-02-17
Also published as: DE10336678A1

Abstract

The invention relates to a toner which can be transferred onto metal, glass, glass ceramics or ceramic substrates or the like substrates that are highly temperature stable by means of electrophotographic printing methods or electrostatic coating methods. The invention further relates to a toner that can be transferred onto a synthetic substrate or the like substrate that is highly temperature stable by means of electrostatic coating methods or a screen printing process and that contains organic components (18) and a synthetic toner matrix (12). At least a part of the glass frits or a part of the organic components (18) has biocidal activity.

Description

toner

The invention relates to a toner which can be transferred to a metal, glass, glass ceramic or ceramic substrate or the like substrate of high temperature resistance and / or burned in a subsequent temperature process by means of electrophotographic printing processes or electrostatic coating processes and the ceramic and / or glassy particles contains a mixture of glass frits and a plastic toner matrix.

The invention further relates to a toner which can be transferred to a plastic substrate or similar substrate of low temperature resistance by means of electrophotographic printing processes or electrostatic coating processes and which contains organic ingredients and a toner matrix made of plastic, which in turn can contain ceramic and / or glassy particles.

Finally, the invention relates to a toner which can be transferred to a substrate by means of a screen printing process and which contains organic ingredients and a screen printing paste as a toner matrix.

It is known from the prior art to apply ceramic or organic color compositions to a substrate surface by means of electrophotographic printing or electrostatic coating processes. Screen printing processes are also known from the prior art.

For example, DE 44 13 168 A1 shows ceramic, i.e. non-metallic, inorganic color compositions for decorating ceramic and glass products, which are applied to a paper support as a transfer agent in the electrophotographic reproduction process. The paper backing is coated with gum arabic, polyvinyl acetate or wax. The coloring substances copied onto the paper support are burned into the glassy or ceramic surface after being applied to the object to be printed. The paper carrier burns. This indirect printing process is cumbersome and a completely residue-free burning of the paper carrier is not always guaranteed. These residues often lead to rejects. The ceramic colors specified in these publications are specially designed for the decoration of ceramic articles. The colors cannot be used on special glass, glass ceramics and glasses with low thermal expansion.

In the known printing or coating processes, toners with colored pigmentations are always used in order to enable color transfer to a substrate. Substrates coated or printed in this way can be used in areas, for example in the kitchen or in the sanitary area, which are exposed to increased microbial attack. The conventional toners offer no protection against this. However, glass substrates are known from the prior art which can have an antimicrobial effect. Such antimicrobial glasses have a biocidal effect and can also have a bacteriocidal and / or fungicidal and / or alkicidal effect.

Glasses of this type are also used in powder or fiber form or in the form of fine particles in order to kill unwanted microorganisms. In this capacity, they can be added to products such as paints, varnishes or polymer materials. They can also have anti-inflammatory, wound healing and light absorbing and light scattering properties.

Glasses with bioactive and sometimes also antimicrobial effects are available from L.L. Hensch, J. Wilson, An Introduction to Bioceramics, World Scientific Publ., 1993, as Bioglas. Such bioglass is characterized by the formation of hydroxyclappatite layers in aqueous media.

Heavy metal-free alkali-alkaline earth silicate glasses with antimicrobial properties are described in DE-A-199 32 238 and DE-A-199 32 239.

In general, the term “glass” is understood to mean non-metallic organic glasses and glass ceramics, whereas “ceramic materials” are understood to mean non-metallic inorganic materials such as glasses, glass ceramics, ceramics and corresponding composites. This definition should also apply in particular in connection with the toner according to the invention.

It is an object of the invention to provide a toner which on the one hand has anti- has microbial properties and can be applied to different substrates by means of an electrophotographic printing process, an electrostatic coating process and / or screen printing process.

This object of the invention is achieved by the features of claims 1, 6 or 7. Advantageous further developments are described in the subclaims.

Accordingly, at least some of the glass frits or the glass portion of the toner have been transferred to a metal, glass, glass ceramic or ceramic substrate or similar substrate of high temperature resistance and / or burned in a subsequent temperature process by means of electrophotographic printing processes or electrostatic coating processes can, biocidal or antimicrobial effect.

With such a toner, a coating or a print can be applied in the electrophotographic printing process that is largely protected against microbial attack.

According to one embodiment, the glass portion can have an antimicrobial glass that contains one or more components made of AgO, ZnO, CuO, SnO, I. The usual concentration, for example of AgO, is 0 to 10% by weight, preferably between 0 to 5% by weight, and particularly preferably between 0 to 2% by weight, whereas the usual concentration, for example of ZnO, is 0 to 40% by weight, preferably between 0 to 20 wt%, and particularly preferably between 0 to 10 wt%. The antimicrobial glass can comprise a silicate glass with the network former Si0 ₂ , a phosphate glass with the network former P ₂ Oβ or a borate glass with the network former B ₂ O ₃ , each of which has at least one of the components Na ₂ 0, Li ₂ O, K ₂ 0 , P ₂ O ₅ , B ₂ 0 ₅ , CaO, BaO, SO ₃ , MgO, Al ₂ 0 ₃ contain.

The toner can in particular have a thermoplastic plastic matrix that melts homogeneously on the substrate in the temperature range from 100 ° C. to 400 ° C. and evaporates and / or burns out almost without residue in the temperature range from 300 ° C. to 500 ° C. With such a matrix, the toner is suitable for processing in the electrophotographic printing process.

According to a further basic idea of the invention, at least some of the organic constituents of the toner, which is to be transferred to a plastic substrate or similar substrate of low temperature resistance by means of electrophotographic printing processes or electrostatic coating processes, can have a biocidal or antimicrobial effect.

Likewise, at least some of the organic ingredients in the toner that are to be transferred to a substrate by means of a screen printing process can have a biocidal or antimicrobial effect.

For this purpose, the part of the organic ingredients with biocidal activity can be Triclosan® from Ciby Geigy or a similar antimicrobial ingredient. Silver-filled zeolites can also be included as a filler for plastic. The effective Ag ⁺ ions are released and released relatively slowly, so that the biocidal effect of the plastics and plastic products they contain is retained for a long time.

In particular if the temperature resistance of the substrate is limited, the toner matrix can have a thermosetting or thermoplastic plastic matrix that can be fixed on the surface of the substrate at temperatures <200 ° C. Melting or even fusing with the substrate material is not necessary here.

Rather, the thermosetting plastic matrix can be fixed on the surface of a substrate preheated in the temperature range <200 ° C. in a hot transfer process and simultaneously cured. Additional heating for post-curing is not necessary.

The thermosetting plastic matrix, which was fixed on the substrate surface in a previous method step, can also be post-cured in the temperature range from 100 ° C. to 200 ° C. on the substrate surface.

According to one embodiment, the plastic matrix has toner resins based on acrylate, in particular styrene acrylate, polymethyl methacrylate. These substances are easy to process during toner production and have good adhesion to the substrate. In addition, these substances burn without residue.

The influence of the depolymerization, the melting, the evaporation and / or decomposition temperature can be selected by choosing different polymers for the plastic matrix can be achieved. Suitable materials have proven to be polyvinyl alcohol, polyoxymethylene, styrene copolymers, polyvinylidene fluoride, polyvinyl butyral, polyesters (unsaturated and / or saturated or mixtures thereof), polycarbonate, polyvinyl pyrrolidone, vinyl imidazole copolymers and polyethers.

The toner can additionally contain charge control substances and / or oxidizing agents in a known manner to improve the image transfer or to decompose the organic without residues. The added oxidants accelerate the thermal decomposition of the plastic matrix.

The toner is additionally coated with additives to improve the wetting when the toner melts on the generally relatively polar and smooth, unlike paper, non-absorbent surface. The polarity of the toners between non-polar, hydrophobic, neutral, polar, hydrophilic, and thus the wetting of the substrates, can be controlled via a suitable choice of known additives. Known flow aids such as aerosils and transfer aids can be used to improve the quality of the print. The proportion of such auxiliaries is between 0 and 1.0% by weight, typically between 0.2 and 0.5% by weight.

To decompose the polymers (depolymerization), peroxides or azo compounds can be added to the toner, but these have decomposition temperatures> 150 ° C., so that the decomposition does not start during the melting phase (fixing phase). In addition, inorganic additives are also possible, for example catalytically active pigments, which accelerate the decomposition of the organic plastic matrix. The toner particles can have an irregular shape and can only be partially enveloped by the plastic matrix.

According to a preferred embodiment, the toner also contains coloring pigments. This means that a print or a coating is achieved not only with anti-microbial but also with decorative properties.

The invention is explained in more detail below on the basis of a preferred embodiment with reference to the attached drawings.

Show it:

1 shows a schematic side view of a toner particle with ceramic, antimicrobial particles;

2 shows a schematic side view of a toner particle with organic, antimicrobial ingredients;

Fig. 3 is a schematic side view and in section of a glass substrate with baked ceramic toner, and

Fig. 4 in a schematic side view and in section a plastic substrate with organic toner fixed thereon.

FIG. 1 shows a schematic side view of a toner particle with ceramic, biocidally active or antimicrobial particles 10, which are contained in a toner plastic matrix 12 are embedded by the toner manufacturing process. The toner matrix 12 consists, for example, of a styrene-acrylate compound or of a polyester compound. The toner particle shown can be transferred to a (not shown) metal, glass, glass ceramic or ceramic substrate or similar substrate of high temperature resistance by means of electrophotographic printing or electrostatic coating and / or baked in a subsequent temperature process.

The ceramic particles 10 consist of a mixture of glass frits, in which at least one component has a biocidal effect.

Depending on the desired antimicrobial activity, more or less biocidal glass components can be contained in the toner particle. The glass portions can be mixed, melted and ground again in a preparatory state, or can be contained in the toner matrix 12 in a mixture with biologically inactive glass frits. The glass portion can contain an antimicrobial ceramic material.

Charge control agents 14 are added as additional additives, and the toner particle is coated with a flow aid 16, for example Aerosil. Color pigments can also be added. Color pigments typically include inorganic compounds, such as metal oxides, mixed phases metal oxide pigments or CIC pigments (complex inorganic color pigments), inclusion pigments, metal powders or flakes, metal colloids, pearlescent or luster pigments based on mica or glassy or SiO ₂ - or Al ₂ O ₃ platelets, fluorescent pigments, magnetic pigments, anticorrosive pigments, transparent pigments, sintered pigments and / or mixtures of pigments with glass frits, pigments for four-color types, etc. or mixtures of the abovementioned variants which have already been adequately described in the literature (for example "Ullmann's Encyclopedia of Industrial Chemistry", Vol. A20, 1992, VCH Publishers , Inc.).

FIG. 2 shows a schematic side view of a toner particle with biocidally active organic substances 18 which are embedded or dissolved in a toner matrix 12 made of plastic by the toner manufacturing process. The toner matrix 12 consists, for example, of a styrene-acrylate compound or of a polyester compound. The toner matrix 12 can exhibit both thermoplastic and thermosetting material behavior.

The toner particle shown is suitable for an electrophotographic printing process or for an electrostatic coating process on a plastic substrate or the like substrate of low temperature resistance.

The biocidal substances can be both inorganic glasses or organic ingredients 18 which are at least partially fused or dissolved in an extrusion process during the toner production. An example of this is Triclosan®, which Ciba Geigy offers as an antimicrobial additive.

Internal charge control agents 14 and external flow aids 16 are also incorporated. In addition, coloring pigments (not shown) for decorative purposes can also be incorporated. In this embodiment, these are preferably organic in nature. FIG. 3 shows a schematic side view and in section of a coated glass substrate 20 onto which the ceramic toner has been burned in by means of a firing process at high temperature. All that remains essentially are the ceramic particles 10, which are at least partially fused to the substrate, here glass.

The toner matrix of the toner used here, as described, for example, with reference to FIG. 1, has a thermoplastic plastic matrix which melts homogeneously on the substrate 20 in the temperature range from 100 ° C. to 400 ° C. and in the temperature range from 300 ° C. to 500 ° C evaporates and / or burns out almost completely. The ceramic particles 10 melt in a further temperature step at typically 500 to 700 ° C. and thereby bond to the substrate.

FIG. 4 shows a schematic side view and in section of a plastic substrate 30 with organic toner fixed thereon, as has already been described with reference to FIG. 2. The organic toner was only melted by a thermal fixing process at a low temperature. Remaining essentially all components of the organic toner, namely the flow aid 16, the internal charge control agents 14, the toner matrix 12 and the organic, antimicrobial ingredients 18.

Toners with a thermoplastic or thermosetting plastic matrix 12 for substrates 30 with lower temperature resistance, such as plastics, are merely fixed on the surface of the substrate 30 and, in the case of a thermosetting plastic matrix 12, are possibly post-cured. This happens at temperatures in the range of 100 to 200 ° C, typically in Range from 130 to 180 ° C. The substrates 30 can also be coated preheated, a subsequent temperature treatment being unnecessary.

An antimicrobial toner can be used for the following purposes: antimicrobial glasses / glass ceramics, for example for domestic appliance applications, refrigerator shelves, glass surfaces in food display applications, vending machines, disinfection devices, glass cutting boards, sink covers. Oven front panes, control panels, glass ceramic cooktops, glass hobtops, fitness equipment, medical devices, display surfaces, touch screens, furniture glass, glass tiles in the sanitary area, doors etc. antimicrobially effective plastic surfaces, for example additionally for worktops, etc. antimicrobially effective ceramic surfaces or enamel surfaces, for example for floor and / or wall tiles, sanitary objects, etc.

Claims

claims

1. Toner which can be transferred by means of an electrophotographic printing process or an electrostatic coating process to a metal, glass, glass ceramic or ceramic substrate or the like substrate (20) of high temperature resistance and / or can be baked in a subsequent temperature process and which is ceramic and / or glassy Contains particles (10) from a mixture of glass frits and a toner matrix (12) made of plastic, characterized in that at least some of the glass frits or the glass portion has a biocidal or antimicrobial effect.

2. Toner according to claim 1, characterized in that the glass portion has an antimicrobial glass which contains one or more components made of AgO, ZnO, CuO, SnO, I.

3. Toner according to claim 1 or 2, characterized in that the glass portion has an antimicrobial glass which contains one or more of the components SiO ₂ , Na ₂ 0, K ₂ O, P ₂ O ₅₎ B ₂ O ₃ , CaO, AgO , ZnO, CuO, MgO, Al ₂ O ₃ , CeO ₂₎ Fe ₂ O ₃ .

4. Toner according to one of claims 1 to 3, characterized in that the toner matrix (12) has a thermoplastic plastic matrix which melts homogeneously in the temperature range from 100 ° C to 400 ° C on the substrate (20) and in the temperature range 300 ° C to 500 ° C evaporates and / or burns out almost without residue.

5. Toner which can be transferred by means of the electrophotographic printing process or electrostatic coating process to a plastic substrate or similar substrate (30) of low temperature resistance and which contains organic ingredients (18) and a toner matrix (12) made of plastic, characterized in that at least some of the organic ingredients (18) have biocidal or antimicrobial activity.

6. Toner according to claim 5, characterized by an addition of antimicrobial glass and / or ceramic particles.

7. Toner which can be transferred to a substrate by means of a screen printing process and which contains organic ingredients and a screen printing paste as a toner matrix, characterized in that at least some of the organic ingredients have a biocidal or antimicrobial effect.

8. Toner according to one of claims 5 to 7, characterized in that the part of the organic ingredients (18) with biocidal action Triclosan® from Ciby Geigy or the like is an antimicrobial ingredient.

9. Toner according to one of claims 5 to 8, characterized in that silver-filled zeolites are contained as a filler for plastic.

10. Toner according to one of claims 5 to 9, characterized in that the toner matrix has a thermosetting or thermoplastic plastic matrix which can be fixed at temperatures <200 ° C on the surface of the substrate.

11. Toner according to one of claims 5 to 10, characterized in that the toner matrix (12) has a thermosetting plastic matrix which can be fixed and / or post-cured in a hot transfer process on the surface of a substrate (30) preheated in the temperature range <200 ° C is.

12. Toner according to one of claims 5 to 11, characterized in that the toner matrix (12) has a thermosetting plastic matrix which post-cured in the temperature range from 100 ° C to 200 ° C on the substrate surface.

13. Toner according to one of claims 1 to 12, characterized in that the plastic matrix contains toner resins based on acrylate, in particular polystyrene, polymethyl methacelate.

14. Toner according to one of claims 1 to 13, characterized in that the plastic matrix polymers, for example polyvinyl alcohol, polyoxymethylene, styrene copolymers, polyvinylidene fluoride, polyvinyl butyral, polyester (unsaturated and / or saturated or mixtures thereof). Contains polycarbonate, polyvinylpyrrolidone, vinylimidazole copolymers and / or polyether.

15. Toner according to one of claims 1 to 14, characterized in that it has peroxides and / or azo compounds with decomposition temperatures> 150 ° C for the degradation of the polymers.

16. Toner according to one of claims 1 to 15, characterized in that it contains charge control substances (14) and / or oxidizing agents as additional additives.

17. The toner according to any one of claims 1 to 16, characterized in that it is additionally coated with a flow aid (16), such as Aerosile.

18. Toner according to claim 16 or 17, characterized in that the additional additives and the flow aids are added in an amount of 0 to 1.0% by weight, in particular 0.2 to 0.5% by weight.

19. Toner according to one of claims 1 to 18, characterized in that the toner particles have an irregular shape and are only partially enveloped by the plastic matrix (12).

20. Toner according to any one of claims 1 to 19, characterized in that it contains coloring pigments.