EP1800327A2

EP1800327A2 - Gas discharge lamp, system and method for hardening materials hardenable by means of uv-light, and material hardened by uv-light

Info

Publication number: EP1800327A2
Application number: EP05802402A
Authority: EP
Inventors: Heiko Runge; Ude Bastian; Karl-Heinz Meyer
Original assignee: Dr Honle AG
Current assignee: Dr Honle AG
Priority date: 2004-10-01
Filing date: 2005-09-30
Publication date: 2007-06-27
Also published as: US20080105830A1; JP2008521162A; WO2006037578A3; DE102004048005A1; WO2006037578A2

Abstract

The invention relates to a gas discharge lamp which is used to harden materials hardenable by means of UV-light, comprising a tube (4) which is filled with a filling gas (3) and which is used to produce a discharge gas used to emit electromagnetic radiation until 200nm by using an inert gas device which is used to prepare an inert gas and to lead the inert gas to the surface of the material which is to be hardened. The invention further relates to a system and to a method for hardening materials which can be hardened by UV-light, in addition to a material hardened due the inventive method.

Description

Dr. Hönle AG P30498WO

A gas discharge lamp, system and method of curing UV light curable materials, and UV light cured material

The invention relates to a gas discharge lamp for curing UV-curable materials according to claim 1, a system for curing UV-curable materials according to claim 13, a method for curing UV-curable materials according to claim 25 and a by UV light-cured material according to claim 35.

In the most diverse areas materials such as paints, printing inks, potting compounds, adhesives and the like are used. Originally and partly still solvent-containing and aqueous systems are used. However, the heat energies used in the drying process are very large and the sometimes high volatile solvent content contributes to a significant environmental impact or attracts a large investment needs when due to air pollution regulations solvent burning or -rück- recovery systems must be installed.

An alternative to conventional solvent-containing systems is in ultraviolet curable materials. Recently, UV curing materials have become widely established in some areas, and UV curing is becoming increasingly important in other areas.

This is for the curing of UV-curable, especially pigmented and thick-layered materials, long-wave UV radiation of 320-380 nm and visible light between 380-450 nm for curing and short-wave radiation between 200-320 nm for surface hardening and to reduce oxygen inhibition used. The curing of pigmented and thick-layered systems is preferably carried out here with photoinitiators which absorb in the visible range> 400 nm. For these reasons, in the UV curing of paints, printing inks, adhesives and potting compounds mainly Hg medium-pressure lamps are used, some of which emit especially in the long-wavelength range (> 400 nm).

Shortwave emitters, z. As excimer laser with a wavelength of 172 nm, produce at the paint surface, for example in clearcoats, under inert conditions or in a vacuum, a very thin through-hardened layer, the deeper

f: \ storage \ p \ pat \ 30000 \ 30498 \ where -_ \ 30498uu0.doc However, lying layers must be post-cured with a medium-pressure lamp. As a result, a matting effect occurs, but the paints can not be completely through-hardened.

Low-pressure lamps with a peak of 185nm are used exclusively for ozone generation and exclusively for photochemical purposes such. As the cleavage of water and the oxidation of organic compounds used to purify air, water or substrate surfaces.

A disadvantage of the method described above, especially with medium-pressure lamps, is a high energy demand of the radiator used, a high heat generation of the radiator - which is a problem for u. a. Temperature-sensitive substrates leads - and a high design complexity and the need for cooling the radiator, which are associated with high system costs.

Furthermore, the UV curing is mainly used for curing 2-dimensional parts such as film and sheet goods. The curing of 3-dimensional parts is still a major problem and u. a. in air by installation of complex UV systems for uniform hardening at all object points or under inert conditions.

It is therefore the object of the present invention to provide a system and a method which reduces the energy consumption and the design effort and minimizes the heat input; Furthermore, lamp systems should be provided which can be better matched to the structure of different 3-dimensional geometries.

The object is achieved by the characterized in claim 1 gas discharge lamp.

According to the present invention, there is disclosed a gas discharge lamp for curing ultraviolet curable materials comprising a filled gas tube (3) for generating a gas discharge for emitting electromagnetic radiation to less than 200nm using an inert gas device for providing an inert gas and supplying the inert gas to the surface of the material to be cured.

The object is further achieved by the invention characterized in claim 13 system. According to the present invention, there is disclosed a system for curing ultraviolet curable materials, comprising a gas discharge lamp for emitting electromagnetic radiation to less than 200nm by means of gas discharge in a filled gas-filled tube and an inert gas device for supplying an inert gas and supplying the inert gas thereto Surface of the material to be hardened.

The object is further achieved by the invention characterized in claim 25 method.

According to the present invention, there is disclosed a method of curing UV-curable materials, comprising the steps of emitting electromagnetic radiation to below 200nm by means of a gas discharge lamp, providing an inert gas, and supplying the inert gas to the surface of the material to be cured.

The object is also achieved according to the invention by the material characterized in claim 35.

According to the present invention, a UV-cured material is disclosed by using a gas discharge lamp for emitting electromagnetic radiation to below 200 nm by gas discharge in a filled gas tube and using an inert gas device for supplying an inert gas and supplying the inert gas to the surface of the inert gas to hardening material.

Preferably, the gas discharge lamp is a low-pressure radiator.

Advantageously, the tube has a diameter of 5mm to 20mm, preferably from 10mm to 15mm, and more preferably from 12mm to 13mm.

According to a preferred embodiment, the tube is made of quartz glass, which transmits wavelengths below 200 nm, in particular up to 185 nm.

Preferably, the tube has a wall thickness between 0.5mm and 2mm, preferably between 0.8mm and 1.5mm, and more preferably between 1mm and 1.3mm. Conveniently, the filling gas consists of mercury and a Ne-Ar-Mi tion in the ratio of Ne 0% to 100% and / or Ar 0% to 100%, preferably Ne 0% to 50% and Ar 50% to 100% and more preferably Ne 20% to 30% and Ar 70% to 80%.

Advantageously, the filling gas has a gas pressure of 0.5 mbar to 10mbar, preferably from 0.5mbar to 5mbar and more preferably from 1mbar to 3mbar.

Preferably, the gas discharge is generated by two electrodes located in the tube and controlled by a ballast connected to the electrodes.

Conveniently, by controlling the power supply of the electrodes, the ballast regulates the discharge tube temperature to 85 ^° C. to 150 ^° C.

The gas discharge can also be generated by high-energy radiation, in particular radiation in the microwave range. The gas discharge may be e.g. also be produced in electrodeless steel systems.

The gas discharge lamp may also be a medium-pressure radiator.

Advantageously, the inert gas is a chemically inert, gaseous compound, preferably argon, nitrogen or carbon dioxide.

The invention will be explained in more detail below with reference to figures. Show

Figure 1 is a schematic representation of a gas discharge lamp and

Figure 2 shows the transmission of different types of quartz.

Figure 1 shows a schematic representation of a gas discharge lamp 1. The gas discharge lamp 1 consists of a vacuum-tight tube 4 with a filling gas 3 with a predetermined filling gas pressure in which the gas discharge takes place, and usually two metallic electrodes 2, which are melted into the tube 4. An electrode 2 supplies the electrons for the discharge, which are supplied via the second electrode 2 again to the external circuit. The emission of the electrons is usually by means of annealing emission (hot electrodes), but can also be caused by emission in a strong electric field or directly by ion impact (ion-induced secondary emission) (cold electrodes). In addition to these emitters, the electrodes can of course also electrodeless emitter units 1 are used, which are characterized by high-energy radiation such. B. microwaves are ignited.

The gas discharge lamp 1 has for operation via a ballast 5, which is connected to the electrodes and ignites the gas discharge in the Gasentladunslampe 1 and supplies a ballast for the operation of the lamp on a circuit. Without a suitable current limit of the gas discharge lamp 1 in an outer

Circuit would increase the current in the gas discharge lamp 1 by increasing the

Charge carriers in gas volume of the tube 4 rise so high that it quickly leads to destruction of the lamp.

UV curable materials can be paints, inks, adhesives, potting compounds or the like.

For the gas discharge lamp 1, both low-pressure lamps and medium-pressure lamps can be used. These are optimized in accordance with the invention such that the wavelength below 200 nm, in particular the wavelength 185 nm, is emitted with particularly high efficiency. Disadvantage of medium-pressure lamps is also here that they produce a large amount of heat, which requires intensive cooling; As a result, they can not be such. As low-pressure radiator in the filled with inert gas space of a curing system are introduced, since the intensive ventilation, the ReSt-O ₂ - concentration increases very quickly to 20%, but they must be externally attached to a curing device. This in turn requires a very expensive equipment of the curing system with quartz disks, which are permeable to UV radiation with a wavelength of <200 nm (eg Suprasil). In addition, the complete, externally mounted radiator unit must be additionally flooded with inert gas, otherwise ozone is formed and thus the short-wave UV radiation does not reach the substrate surface. Another way of curing with Hg medium pressure jets in an inert gas atmosphere is the direction of the radiation with a cooling fluid, eg. As water to perform. For this example, reflectors and / or housing are cooled with the cooling fluid. There is no turbulence in the inert gas filled irradiation room.

Mercury low-pressure discharge lamps are radiation sources that generate radiation in their plasma discharge by the impact ionization processes with the mercury atoms. This radiation is spectrally distributed from ultraviolet to infrared. The most intense radiation components are in marked contrast to the medium-pressure radiators essentially at the wavelengths of 254nm and 185nm. The smaller the diameter of the tube 4, the higher the 185 nm yield. Optimally, the tube 4 has a diameter of 5mm to 20mm, preferably from 10mm to 15mm and more preferably from 12mm to 13mm, with a diameter of 12mm to 13mm also from a production point of view is optimal.

The tube 4 has a wall thickness between 0.5mm and 2mm, preferably between 0.8mm and 1.5mm, and more preferably between 1mm and 1.3mm.

The filling gas 3 of the low-pressure radiator may be a mercury and Ar filling or a mercury and noble gas mixture such as Ar-Kr and Ar-Ne. Here, the noble gas mixtures Ar-Kr and Ar-Ne show a higher 185 nm yield than the pure Ar filling. In this case, the noble gas mixture Ne-Ar has proved to be optimal with a ratio of Ne 0% to 100% and / or Ar 0% to 100%, preferably Ne 0% to 50% and Ar 50% to 100%, particularly preferably Ne 20 % to 30% and Ar 70% to 80%. In addition, the 185 nm yield can be increased by reducing the gas pressure. The filling gas 3 has a gas pressure of 0.5 mbar to lOmbar and preferably from 0.5 mbar to 5 mbar. However, since values of less than 2 mbar gas pressure result in a reduction in the intensity of the 185 nm peak, the optimum gas pressure of the filling gas 3 is 2 mbar to 3 mbar.

By using different quartz materials for the tube 4, the radiated wavelength and thus also the 185 nm yield can be influenced. FIG. 2 shows the transmission of different types of quartz for UV lamps. Here, the percentage transmission as a function of the wavelength in nanometers is graphically plotted for different types of quartz. As can be seen from the graph, only certain types of quartz transmit wavelengths of less than 200 nm and in particular wavelengths of 185 nm. Transmittances at 185nm are shown by rock crystal and the synthetic quartz "Suprasil" Furthermore, the 185nm yield is increased by the use of tubes 4 with a small wall thickness.The quartz glasses "Ilmasil PS" with 1.3mm wall thickness and In addition to the quartz types based on SiO ₂ , it is also possible to use ceramic or other inorganic materials which have a transmission of UV radiation in the range from 100 nm to 200 nm.

The emission of the 185nm line increases with increasing temperature of the radiator up to values around 150 ° C. In addition, the emission decreases significantly due to the onset of self-absorption of the mercury resonance line. This requires that the radiator is not heated continuously by a constant lamp current and thus the radiation intensity maxima runs through, but that its tube wall temperature can be kept constant by controlling the lamp current to the desired value. Thus, the radiation intensity can be kept constant.

The gas discharge lamp 1 therefore has a ballast 5, which regulates the lamp power supply. Here, a particularly high 185nm yield in the range of 85 ° C to 150 ° C resulted. In addition, the 185 nm yield decreases again, with a reduction in the filling pressure of the broad maximum range is reduced and the 185 nm yield at higher temperatures decreases much steeper again.

Depending on the lamp current results in a temperature of 90 ° C to 150 ° C. At the low lamp current of 50OmA z. B. in a radiator of length 300mm an electrical active power of about 16 watts and the current 1.2A an electric

Power of 33 watts introduced. This results in an efficiency of

Radiation yield of 13.5% at 0.5 A and 9% at 1.2 A. The optimum

Operating point at IA gives 150% efficiency over a conventional synthetic quartz emitter. The determined powers of the 185 nm radiation are in the range between 2 and 3 watts.

The ballast 5 is adjustable in its current in a wide range from a basic value by + 50%, d. H. for the low-pressure radiator according to the invention of 0.9A ± 50% (0.45 A to 1.35 A). For other radiator types, the corresponding basic values can then be adapted by simply exchanging two reactors and one capacitor. The current setting in the ± 50% range can be done manually by a potentiometer or via a voltage interface remote controlled. In the case of the ballast 5 according to the invention, this voltage interface is controlled via a comparator circuit, which compares the pipe wall temperature with a setpoint temperature, or the current is set with voltage fixed values.

The tube 4 of the gas discharge lamp 1 can have a wide variety of geometries (meandering, curved or helical). Optimum utilization of the generated radiation is given in a cylindrical shape. While other geometries interact with each other by self-picking up some of the generated radiation, the 185 nm yield is still high. When using a medium-pressure radiator as a gas discharge lamp, the tube 4 optimally has a length of 10 to 3000 mm and a tube diameter of about 16 to 28 mm. The discharge tube temperature is approximately between 700 ° C and 900 ° C. As a material for the tube 4, a quartz glass is again taken, which transmits wavelengths of less than 200 nm, in particular of 185 nm.

In order to prevent the formation of ozone produced by UV radiation under oxygen and to suppress the effect of Sauer substance inhibition in radically curing paints, printing inks, adhesives and potting compounds, the curing process takes place under an inert gas (inert gas). An inert gas device serves to provide the inert gas and supply the inert gas to the surface of the material to be cured. As inert gases, any chemical inert gaseous compounds can be used such. Noble gases such as helium or argon; but it can also z. As nitrogen or carbon dioxide are used as inert gas. Carbon dioxide can z. B. be used in the form of dry ice or gaseous. In order to achieve perfect coating properties, the inerting process uses a residual O ₂ concentration of between 0.0001 and 10%, preferably between 0.3 and 3%.

UV-curable materials consist essentially of photoinitiators, prepolymers (precrosslinked basic building blocks), monomers (basic building blocks as reactive diluents used), additives, fillers, dyes and / or pigments. By the action of UV radiation, free radicals are formed from the photoinitiators contained in these materials, which trigger a crosslinking of the system and cure it in a very short time.

As radiation-curable compounds come z. As (meth) acrylic compounds, vinyl ethers, vinylamides, unsaturated polyesters z. B. based on maleic acid or formaric optionally with styrene as a reactive diluent or maleimide / vinyl ether systems into consideration.

Preference is given to (meth) acrylate compounds, such as polyester (meth) acrylates, polyether (meth) acrylates, urethane (meth) acrylates, epoxy (meth) acrylates,

Silicone (meth) acrylates, acrylated polyacrylates. At least 40 mol%, more preferably at least 60% of the radiation-curable ethylenically unsaturated groups, are preferably (meth) acrylic groups.

The radiation-curable compounds may contain further reactive groups, eg. As melamine, isocyanate, epoxy, anhydride, alcohol, carboxylic acid groups for additional thermal curing, eg. B. by chemical reaction of alcohol, Carboxylic acid, amine, epoxide, anhydride, isocyanate or melamine groups (dual eure).

The radiation-curable compounds may, for. B. as a solution, for. B. in an organic solvent or water, as an aqueous dispersion or emulsion, as a powder or as a liquid 100% material.

The radiation-curable compounds and thus also the radiation-curable compositions are preferably free-flowing at room temperature. The radiation-curable compositions preferably contain less than 20% by weight, in particular less than 10% by weight, of organic solvents and / or water. They are preferably solvent-free and anhydrous (100% solids).

The radiation-curable compositions may contain other constituents in addition to the radiation-curable compounds as a binder. In consideration come z. As pigments, flow control agents, dyes, stabilizers, etc. For curing with UV light commercially available photoinitiators are generally used.

Suitable photoinitiators z. As benzophenone, alkylbenzophenones, hologenmethylierte benzophenones, Michler's ketone, anthrone and halogenated benzophenones. Further common photoinitiators are α-hydroxiketones, α-amino ketones, thioxanthones and methylbenzoyl formate (MBF). Benzoin and its derivatives are also suitable. Also effective photoinitiators are anthraquinone and many of its derivatives, for example, β-methylanthraquinone, tert-butylanthraquinone and Anthrachinoncarbonsärueester and, particularly effective, photoinitiators with a Acylphosphinoxidgruppy as Acylphosphinoxide or Bisacylphosphinoxide, z. B. 2,4,6-Trimethylbenzoldiphenylphosphinoxid (Lucirin® TPO).

It is an advantage of the invention that the content of the photoinitiators in the radiation-curable composition can be significantly reduced.

Preferably, the radiation-curable compositions contain less than 10 parts by weight, in particular less than 4 parts by weight, more preferably less than 1.5 parts by weight of photoinitiator per 100 parts by weight of radiation-susceptible compounds.

Sufficient in particular is an amount of 0.01 parts by weight to 1.5 parts by weight, in particular 0.01 to 1 part by weight of photoinitiator.

The proposed gas discharge lamp 1 in conjunction with the inert gas device is suitable both for the curing of free-radical and cationic lacquers, printing inks, adhesives or casting compounds. Both clearcoats and pigmented systems in the colors z. As white, cyan, magenta, yellow or black and mixtures of these are cured. For pigmented paints, printing inks, adhesives or potting compounds, this process can be used Layer thicknesses up to> 40 microns are cured. Clearcoats or filled systems can also be easily cured in layer thicknesses of up to 2000 μm. It has been shown that lacquer systems which contain UV absorbers to increase the UV and weathering resistance, in layer thicknesses> 100 .mu.m and highly pigmented white systems with z. As titanium dioxide as a pigment, can be cured easily.

The distance between the gas discharge lamp 1 in this method can be between 1 cm and> 18 cm from the substrate surface. It can be used to cure the paints, printing inks, adhesives and potting compounds one or more radiators or radiator arrays. Due to the low heat emission of the radiators, the coated and hardened substrate, apart from the heat of reaction, heats only insignificantly.

Another application is the pretreatment of substrates to improve substrate adhesion; In this case, the surface of the substrate is irradiated under inert conditions with one or more radiator units 1 and "activated", which results in an increase in the surface tension of the substrate. Adhesives or potting compounds react and produce a chemical bond between the substrate and the coating, and the coating material can subsequently be cured under inert conditions with one or more other radiator units 1. This can significantly improve the adhesion of the paints, printing inks, adhesives or potting compounds to various substrates In another method, the substrate pretreated with one or more UV emitter units 1 under inert conditions may be pretreated with a photoactive "UV primer"; a chemical bond is formed between substrate and primer; This effect can be further improved by a further UV irradiation step with one or more emitter unit (s) 1 under inert conditions. After subsequent coating with UV-curable coating materials and renewed UV curing under inert conditions with one or more UV units 1, a chemical bond between primer and coating material is now produced. Through this process, the adhesion of UV-crosslinkable systems to various substrates can be significantly improved. In both of these methods for increasing the surface tension and improving the adhesion of the substrate, the UV curing in the subsequent primer and coating steps can also be carried out with conventional medium-pressure lamps in air after the pretreatment step with emitter unit (s) 1 under inert conditions. Another application of the emitter unit 1 is in the field of sterilization, sterilization and / or disinfection of substrate surfaces.

Another application of the emitter unit 1 is the production of dull and dull matt surfaces.

An advantage of the system and method according to the invention lies in the low temperature development in the UV curing, since little energy is introduced through the low-pressure radiator. This is particularly significant in the coating of temperature-sensitive substrates such as plastics, paper, wood, etc. Furthermore, low-pressure radiators have a significantly lower energy consumption compared to medium-pressure radiators, resulting in reduced energy costs. Furthermore, any possible geometry can be reproduced by the gas discharge lamps according to the invention, that is, the lamp can be meandering or U-shaped, which can be adapted optimally to the surface for curing in objects with a curved surface. Furthermore, the curing of clearcoats and pigmented systems in a much shorter time is possible. The hardening of thick layers can also be carried out with the gas discharge lamp under inert gas according to the invention. Due to the low temperature development in the low-pressure radiator, the requirement of cooling the radiator falls away, whereby the design complexity is reduced and the handling of the radiator is simplified because, for example, a radiator change without waiting for cooling is possible. Due to the reduced design effort and the system costs are reduced. Furthermore, the pretreatment of substrates is possible. In addition, the spotlight can still be used for sterilization and disinfection and the curing of both radical and cationic curing systems and UV-stabilized paints is possible. It is also possible to bond UV-transparent substrates (cationic and free-radical) and non-transparent substrates with cationic adhesives. Another application is the matting and curing of pigmented systems.

The process can be carried out under inert conditions, for example for the finishing of sheet-like materials such as paper, films or sheets for printing, coating and lamination of two- and three-dimensional bodies as well as for the refinement of 3-dimensional solids in stationary or continuous operation.

Examples Unless otherwise stated, all experiments were carried out with 2 optimized UV low pressure emitters with enhanced emission in the range of 185 nm. Normal amalgam radiators (conventional quartz) show no emission at 185 nm in the short-wave UV range, but only at 254 nm. Synthetic quartz amalgam radiators exhibit emissions at 254 nm and 185 nm, but the emission at 185 nm is significantly lower than the optimized ones spotlights.

1. Hardening of a UV clearcoat

A solvent-based UV clearcoat from DuPont Performance Coatings was applied to a glass plate (SD about 40 μm, FK = 50%), the solvent was evaporated and then introduced into a UVACube inert. It was cured with 2 low-pressure lamps at a distance from the radiator of about 6 cm (residual O ₂ concentration = 1.5%). After 1 s exposure time, the material is completely cured as a high-gloss, scratch-resistant film. In KMnO ₄ -TeSt held against white paper, no coloration of the film can be seen.

2. Hardening of a UV clearcoat

A clear coat consisting of 50 g of Laromer® PO 84 F (BASF), 1.5 g of TMPTA (BASF) and 1 g of Darocur® MBF (Ciba SC) as photoinitiator was applied to a glass plate

- Applied (SD about 40 microns) and introduced into a UVACube inert. It was with 2

Emitters cured at a distance of about 6 cm from the radiator (ReSt-O ₂ -

Concentration = 1.5%). After 2 s exposure time, the material is completely cured as a high-gloss, scratch-resistant film. In the KMnO ₄ -TeSt held against white paper, a minimal coloration of the film can be seen.

3. Hardening of a UV clearcoat as potting compound

The same varnish is filled in an aluminum lid (SD approx. 3 mm). The material was then exposed in the UVACube inert at a distance from the radiator of about 18 cm with 2 low-pressure radiators for 60 s (residual O ₂ concentration = 1.4%). The mass is completely cured, the surface scratch resistant; It has formed a soft, about 3 mm thick polymer.

4. Hardening of a UV Absorber-containing UV Clearcoat (MBF)

A clear coat consisting of 100 g of Laromer® PO 84 F (BASF), 5.0 g of Tinuvin® 1130 (Ciba SC) as UV absorber and 2.0 g of Darocur® MBF (Ciba SC) as photoinitiator was applied to a white cardboard (SD about 12 microns) and introduced into a UVACube inert. It was cured with 2 spotlights at a distance from the radiator of about 6 cm (residual O ₂ concentration = 1.4%). After 2 s exposure time, the material is completely cured as a high-gloss, scratch-resistant film. In the KMnO ₄ -TeSt held against white paper, a minimal coloration of the film can be seen.

5. Hardening of a UV Absorber-containing UV Clearcoat in a Thick Layer (MBF)

The same paint is applied in a layer thickness of about 40 microns on a white cardboard. The material was then exposed in the UVACube inert at a distance from the radiator of about 6 cm with 2 low-pressure radiators for 30 s (residual O ₂ concentration = 1.4%). The film is fully cured, the high gloss surface is absolutely scratch resistant and. After an exposure time of 10 s, the film is not fully cured.

6. Hardening of a UV Absorber-containing UV Clearcoat in a Thick Layer (MBF)

The same paint is applied in a layer thickness of about 100 microns on a white cardboard. The material was then exposed in the UVACube inert at a distance from the radiator of about 6 cm with 2 low-pressure lamps for 60 s (ReSt-O ₂ concentration = 1.4%). The film is completely cured, the high-gloss surface is absolutely scratch-resistant.

7. Hardening of UV-Clearcoat UV-Absorber (TPO)

A clearcoat consisting of 100 g of Laromer® PO 84 F (BASF), 5.0 g of Tinuvin® 1130 (Ciba SC) as UV absorber and 2.0 g of Lucirin® TPO-L (BASF) as photoinitiator was applied to a white board (SD about 40 microns) and introduced into a UVACube inert. It was cured with 2 spotlights at a distance from the radiator of about 6 cm (residual O ₂ concentration = 1.4%). After 5 s exposure time, the material is completely cured as a high-gloss, scratch-resistant film. In the KMnO ₄ -TeSt held against white paper, a minimal coloration of the film can be seen.

8. Hardening of a UV Absorber-containing UV Clearcoat in Thick Film (TPO)

The same paint is applied in a layer thickness of about 100 microns on a white cardboard. The material was then exposed in UVACube inert at a distance from the radiator of about 6 cm with 2 Niederdruckstrahleni 5 s (residual O ₂ concentration = 1.4%). The film is completely cured, the high-gloss surface is absolutely scratch-resistant.

9. Hardening of a radically curing UV inkjet ink white

A white, highly pigmented inkjet ink is applied to white cardboard in an SD of 12 μm and introduced into a UVACube inert. Then, at a distance to the radiator of about 6 cm <2s with 2 radiators exposed (residual O ₂ - concentration - 1.4%). The material is fully cured and shows a shiny surface.

If the UV curing is carried out with amalgam lamps (normal

Quartz), the material is not yet cured after an exposure time of 90 s.

If the UV curing is carried out under the same conditions with a "normal" UV low-pressure emitter made of synthetic quartz, the material is only hardened after 10 s and has a matte surface, clearly showing the effect of the emitter with the increased emission at 185 nm.

10. Hardening of a radically curing UV inkjet ink white

A white, highly pigmented inkjet ink is applied to white cardboard in an SD of 40 μm and introduced into a UVACube inert. Then, at a distance of 18 cm from the emitter, 60 s are exposed with 2 emitters (ReSt-O ₂ concentration = 1.4%). The material is fully cured and shows a textured surface.

11. Hardening of a radically curing UV inkjet yellow

A yellow, highly pigmented inkjet ink is applied to white cardboard in an SD of 12 μm and introduced into a UVACube inert. Then, at a distance from the radiator of approx. 6 cm «2 s, exposure is made with 2 radiators (ReSt-O ₂ concentration = 1.4%). The material is fully cured and shows a shiny surface.

If the UV curing is carried out with amalgam lamps (normal quartz) under the same conditions, the material is only cured after an exposure time of 90 s and shows a structured surface.

If UV curing is carried out under the same conditions with a "normal" UV low-pressure emitter made of synthetic quartz, the material is only cured after 10 s and has a matte surface. This clearly shows the effect of the emitter with the increased emission at 185 nm.

12. Hardening of a radically curing UV inkjet ink yellow

A yellow, highly pigmented inkjet ink is applied to white cardboard in an SD of 40 μm and introduced into a UVACube inert. Then, at a distance of approx. 6 cm, 20 sec are exposed to 2 emitters (ReSt-O ₂ concentration = 1.4%). The material is fully cured and shows a textured surface.

13. Hardening of a radically curing UV inkjet ink cyan

A cyan, highly pigmented inkjet ink is applied to white cardboard in an SD of 12 μm and placed in a UVACube inert. Subsequently, at a distance from the radiator of about 6 cm 2 s with 2 radiators exposed (ReSt-O ₂ - concentration = 1.4%). The material is fully cured and shows a shiny surface.

If the UV curing is carried out with amalgam lamps (normal quartz) under the same conditions, the material is only cured after an exposure time of 90 s and has a glossy surface.

If UV curing is carried out under the same conditions with a "normal" UV low-pressure emitter made of synthetic quartz, the material is only hardened after 5 s and has a matte surface, clearly showing the effect of the emitter with the increased emission at 185 nm.

14. Hardening of a radically curing UV inkjet ink magenta

A magenta-colored, highly pigmented inkjet ink is applied to white cardboard in an SD of 12 μm and introduced into a UVACube inert. Subsequently, at a distance to the radiator of about 6 cm <2 s with 2 radiators exposed (residual O ₂ concentration = 1.4%). The material is fully cured and shows a shiny surface. If the UV curing is carried out with amalgam lamps (normal quartz) under the same conditions, the material is only cured after an exposure time of 90 s and has a glossy surface.

If the UV curing is carried out under the same conditions with a "normal" UV low-pressure emitter made of synthetic quartz, the material is only after 5 s cured and has a slightly frosted surface. This clearly shows the effect of the emitter with the increased emission at 185 nm.

15. Hardening of a radically curing UV inkjet ink black

A black, highly pigmented inkjet ink is applied to white cardboard in an SD of 12 μm and introduced into a UVACube inert. Then, at a distance from the radiator of about 6 cm, 5 sec are illuminated with 2 radiators (ReSt-O ₂ concentration = 1.4%). The material is fully cured and shows a matte finish.

If the UV curing is carried out with amalgam lamps (normal quartz) under the same conditions, the material is only cured after an exposure time of 90 s and has a matte surface. If UV curing is carried out under the same conditions with a "normal" UV low-pressure emitter made of synthetic quartz, the material is only cured after 10 s and has a matte surface.

This clearly shows the effect of the emitter with the increased emission at 185 nm.

16. Hardening of a cationic curing UV flexo color white

A white, highly pigmented flexo ink is applied to white cardboard in an SD of 12 μm and placed in a UVACube inert. Then, at a distance of approx. 6 cm, 20 sec are exposed to 2 emitters (ReSt-O ₂ concentration = 1.4%). The material is fully cured and shows a matte finish.

Performing the same experiment in an SD of 6 microns, the material is fully cured after 10 s and shows a shiny surface.

17. Hardening of a cationic curing UV flexo yellow

A yellow, highly pigmented flexo ink is applied to white cardboard in an SD of 12 μm and introduced into a UVACube inert. Then, at a distance of approx. 6 cm, 20 sec are exposed to 2 emitters (ReSt-O ₂ concentration = 1.4%). The material is fully cured and shows a shiny surface.

Performing the same experiment in an SD of 6 microns, the material is fully cured after 10 s and shows a shiny surface. 18. Curing a cationic curing UV flexo cyan

A cyan-colored, highly pigmented flexo ink is applied to white cardboard in an SD of 12 μm and introduced into a UVACube inert. Then, at a distance from the radiator of approx. 6 cm, 30 s are illuminated with 2 radiators (residual O ₂ concentration = 1.4%). The material is fully cured and shows a matte finish.

If the same experiment is carried out in an SD of 6 μm, the material is completely cured after 10 s and shows a matte surface.

19. Hardening of a cationic curing UV flexo magenta

A magenta-colored, highly pigmented flexo ink is applied to white cardboard in an SD of 12 μm and introduced into a UVACube inert. Then, at a distance of approx. 6 cm, 20 seconds are irradiated with 2 beams (ReSt-O ₂ -

Concentration = 1.4%). The material is fully cured and shows a shiny surface.

20. Hardening of a cationically curing UV flexo black

A black, highly pigmented flexo ink is applied to white cardboard in an SD of 12 μm and introduced into a UVACube inert. Then, at a distance of approx. 6 cm from the radiator, exposure is made for 30 s with 2 radiators (ReSt-O ₂ concentration = 1.4%). The material is not completely cured and shows a dull matt surface.

If the same experiment is carried out in an SD of 60 μm, the material is completely cured after 10 seconds and shows a dull matt surface.

21. Preparation of matt surfaces with cationic curing UV flexo inks

If the cationic curing flexographic inks are exposed in an SD of about 12 μm for only 10 s, "dull matt" surfaces are obtained, whereas the deeper layers are not yet cured fix this surface structure and create frosted surfaces. 22. Pre-treatment of plastic surfaces to improve the adhesion of paints, printing inks, adhesives or potting compounds.

A commercially available PMMA plate is exposed for approx. 10 s at a distance of approx. 6 cm to the spotlight with 2 optimized low-pressure lamps. The surface tension of the plastic changes from approx. 38 Nm / m to approx. 46 Nm / m. After about 20 s of irradiation, surface tension values> 50 Nm / m are achieved. If one applies to the thus treated surface a e.g. free radical curable UV varnish, it shows good adhesion to the substrate, while adhesion to the untreated PMMA is not given.

By applying a primer or UV primer on the pretreated surface and then applying and curing a e.g. free-radically curing UV varnish (if necessary, additional UV irradiation can be carried out after primer application), the adhesion to the PMMA can be significantly improved again. Analogous results have also been achieved on plastics such as PE, PP, PA, Teflon and also on silicone paper.

Claims

claims

A gas discharge lamp for curing ultraviolet curable materials comprising a filled gas (3) tube (4) for generating a gas discharge for emitting electromagnetic radiation to below 200nm using an inert gas device for supplying an inert gas and supplying the inert gas the surface of the material to be hardened.

2. Gas discharge lamp according to claim 1, characterized in that it is a low-pressure radiator in the gas discharge lamp (1).

3. Gas discharge lamp according to claim 1 or 2, characterized in that the tube (4) has a diameter of 5mm to 20 mm, preferably from 10 mm to 15mm and more preferably from 12mm to 13mm.

4. Gas discharge lamp according to one of claims 1 to 3, characterized in that the tube (4) is made of quartz glass, which transmits wavelengths below 200 nm, in particular up to 185 nm.

5. Gas discharge lamp according to one of claims 1 to 4, characterized in that the tube (4) has a wall thickness between 0.5mm and 2mm, preferably between 0.8mm and 1.5mm and more preferably between lmm and 1.3mm.

6. Gas discharge lamp according to one of claims 1 to 5, characterized in that the filling gas (3) of mercury and a Ne-Ar mixture in the ratio of Ne 0% to 100% and / or Ar 0% to 100%, preferably Ne 0% to 50% and Ar 50% to 100%, and more preferably Ne 20% to 30% and Ar 70% to 80%.

7. Gas discharge lamp according to one of claims 1 to 6, characterized the filling gas (3) has a gas pressure of 0.5 mbar to 10 mbar, preferably of 0.5 mbar to 5 mbar and particularly preferably of 1 mbar to 3 mbar.

8. Gas discharge lamp according to one of claims 1 to 7, characterized in that the gas discharge generated by two in the tube (4) located electrodes (2) and by a with the electrodes (2) connected ballast (5) is controlled.

9. Gas discharge lamp according to claim 8, characterized in that the ballast (5) by controlling the power supply of the electrodes (2) controls the discharge tube temperature to 85 ⁰ C to 150 ° C.

10. Gas discharge lamp according to one of claims 1 to 7, characterized in that the gas discharge is generated electrode-free by high-energy radiation, in particular radiation in the microwave range.

11. Gas discharge lamp according to claim 1, characterized in that it is a medium-pressure radiator in the gas discharge lamp (1).

12. Gas discharge lamp according to one of claims 1 to 11, characterized in that it is the inert gas is a chemically inert, gaseous compound, preferably argon, nitrogen or carbon dioxide.

A system for curing ultraviolet curable materials, comprising a gas discharge lamp (1) for emitting electromagnetic radiation to less than 200nm by means of a gas discharge in a tube (4) filled with inflation gas (3) and an inert gas device for supplying an inert gas and supplying of the inert gas to the surface of the material to be cured.

14. System according to claim 13, characterized in that it is a low-pressure radiator in the gas discharge lamp (1).

15. System according to claim 13 or 14, characterized the tube (4) has a diameter of 5 mm to 20 mm, preferably of 10 mm to 15 mm and particularly preferably of 12 mm to 13 mm.

16. System according to any one of claims 13 to 15, characterized in that the tube (4) is made of quartz glass, which transmits wavelengths below 200nm in particular to 185nm.

17. System according to any one of claims 13 to 16, characterized in that the tube (4) has a wall thickness between 0.5mm and 2mm, preferably between 0.8mm and 1.5mm and more preferably between lmm and 1.3mm.

18. System according to any one of claims 13 to 17, characterized in that the filling gas (3) of mercury and a Ne-Ar mixture in the ratio of Ne 0% to 100% and / or Ar 0% to 100%, preferably Ne 0% to 50% and Ar 50% to 100%, and more preferably Ne 20% to 30% and Ar 70% to 80%.

19. System according to any one of claims 13 to 18, characterized in that the filling gas (3) has a gas pressure of 0.5mbar to lOmbar, preferably from 0.5mbar to 5mbar and more preferably from lmbar to 3mbar.

20. System according to any one of claims 13 to 19, characterized in that the gas discharge generated by two in the tube (4) located electrodes (2) and by a with the electrodes (2) connected ballast (5) is controlled.

21. System according to claim 20, characterized in that the ballast (5) by controlling the power supply of the electrodes (2) controls the discharge tube temperature to 85 ⁰ C to 150 ° C.

22. System according to any one of claims 13 to 19, characterized in that the gas discharge is generated electrode-free by high-energy radiation, in particular radiation in the microwave range.

23. System according to claim 13, characterized in that it is a medium-pressure radiator in the gas discharge lamp (1).

24. System according to any one of claims 13 to 23, characterized in that it is the inert gas is a chemically inert, gaseous compound, preferably argon, nitrogen or carbon dioxide.

25. A method of curing UV curable materials, comprising

steps

Emission of electromagnetic radiation below 200nm by means of a

Gas discharge lamp (1),

Providing an inert gas and supplying the inert gas to the surface of the material to be cured.

26. The method according to claim 25, characterized by

Providing the tube (4) with a diameter of 5mm to 20mm, preferably from 10mm to 15mm and more preferably from 12mm to 13mm.

27. The method according to any one of claims 25 to 26, characterized by

Providing the tube (4) made of quartz glass, which transmits wavelengths below 200nm in particular to 185nm.

28. The method according to any one of claims 25 to 27, characterized by

Provision of the tube (4) with a wall thickness between 0.5mm and 2mm, preferably between 0.8mm and 1.5mm, and more preferably between 1mm and 1.3mm.

29. The method according to any one of claims 25 to 28, characterized by

Providing a filling gas (3) consisting of mercury and a Ne-Ar mixture in the ratio of Ne 0% to 100% and / or Ar 0% to 100%, preferably Ne 0% to 50% and Ar 50% to 100% and more preferably Ne 20% to 30% and Ar 70% to 80%.

30. The method according to any one of claims 25 to 29, marked by

Providing a gas pressure of 0.5 mbar to lOmbar, preferably from 0.5mbar to 5mbar and more preferably from lmbar to 3mbar for the filling gas (3).

31. The method according to any one of claims 25 to 30, characterized by

Generating the gas discharge by two electrodes (2) located in the tube (4) and controlling by a ballast (5) connected to the electrodes (2).

32. The method according to claim 31, characterized by

Controlling the discharge tube temperature to 85 ° C to 150 ° C by the ballast (5) by controlling the power supply of the electrodes (2).

33. The method according to any one of claims 25 to 30, characterized by

Generating the gas discharge electrode-free by high-energy radiation in particular radiation in the microwave range.

34. The method according to any one of claims 25 to 33, characterized by

Using a chemically inert, gaseous compound, preferably argon, nitrogen or carbon dioxide as the inert gas.

35. UV-cured material using a gas discharge lamp (1) for emitting electromagnetic

Radiation to below 200nm by means of a gas discharge in a filling gas (3) filled tube (4) and an inert gas device for providing an inert gas and supplying the inert gas to the surface of the material to be cured.

36. Material according to claim 35, characterized in that it is a low-pressure radiator in the gas discharge lamp (1).

37. Material according to claim 35 or 36, characterized in that the tube (4) has a diameter of 5mm to 20 mm, preferably from 10 mm to 15mm and more preferably from 12mm to 13mm.

38. Material according to one of claims 35 to 37, characterized in that the tube (4) is made of quartz glass, which transmits wavelengths below 200 nm, in particular up to 185 nm.

39. Material according to one of claims 35 to 38, characterized in that the tube (4) has a wall thickness between 0.5mm and 2mm, preferably between 0.8mm and 1.5mm and more preferably between lmm and 1.3mm.

40. Material according to one of claims 35 to 39, characterized in that the filling gas (3) of mercury and a Ne-Ar mixture in the ratio of Ne 0% to 100% and / or Ar 0% to 100%, preferably Ne 0% to 50% and Ar 50% to 100%, and more preferably Ne 20% to 30% and Ar 70% to 80%.

41. Material according to one of claims 35 to 40, characterized in that the filling gas (3) has a gas pressure of 0.5mbar to lOmbar, preferably from 0.5mbar to 5mbar and more preferably from lmbar to 3mbar.

42. Material according to one of claims 35 to 41, characterized in that the gas discharge generated by two in the tube (4) located electrodes (2) and by a with the electrodes (2) connected to ballast (5) is controlled.

43. Material according to claim 42, characterized in that the ballast (5) by controlling the power supply of the electrodes (2) controls the discharge tube temperature to 85 ° C to 150 ⁰ C.

44. Material according to one of claims 35 to 41, characterized in that the gas discharge is generated electrode-free by high-energy radiation, in particular radiation in the microwave range.

45. Material according to claim 35, characterized in that the gas discharge lamp (1) is a medium-pressure radiator.

46. Material according to one of claims 35 to 45, characterized in that it is the inert gas is a chemically inert, gaseous compound, preferably argon, nitrogen or carbon dioxide.