EP2186574A1

EP2186574A1 - Ultraviolet drying method for repairing paint defects in the automotive industry

Info

Publication number: EP2186574A1
Application number: EP08805360A
Authority: EP
Inventors: Cesar MIRÓ ESCARTÍ
Original assignee: Bulma Tecnologia SL
Current assignee: Bulma Tecnologia SL
Priority date: 2007-08-09
Filing date: 2008-07-30
Publication date: 2010-05-19
Also published as: WO2009027554A4; EP2186574A4; ES2326301B1; WO2009027554A1; ES2326301A1

Abstract

The invention relates to a method comprising a step involving the drying of a primed filler, using UV-ray reflectors or heads positioned at a distance of between 100 mm and 1000 mm from the part to be repaired, emitting UV light with a wavelength of between 50 and 650 nm. Said wavelength can be obtained using mercury vapour, or alternatively gallium lamps. The following steps can be performed indiscriminately on the dried, retouched paint surface, namely: a step in which the repaired surface is varnished with UV varnish; a step in which the contour of the repaired surface is varnished with anti-fogging UV varnish; and a step in which the varnish layer is cured using ultraviolet radiation, all of said steps using UV-ray reflectors and heads.

Description

Technical sector

The ultraviolet drying method for repairing paint defects in the automotive industry uses inside the production processes in chain of components of bodyworks in his painting phase by means of the use of a rapid drying for ultraviolet radiation object of the present invention.

Background Art

The drying technology by radiation of ultraviolet light, also called treatment or cured by UV, is already known and these are used in the field of the serigraphy and adhesives, layout designs of integrated circuits, medical applications in odontology for the products polymerization. Cured saying, it supposes the polymerization that involves the adhesion, union and hardening of two elements in the same product with components of plastic resin that a photoinitiator contains. The photoinitiator is a chemical reagent that causes the beginning from the polymerization to having been exhibited to the ultraviolet light.
The ultraviolet beams application with certain wavelengths in the hardening of films or layers of polyester on different products is already known, like that the Patent of invention ES390290 by ROBERT HILDEBRANT MASCHINENBAU (1971 ). In the sector of the automotive, the application of technology of treatment of polymerization for UV is very recent, and it is specializing since it admits diverse procedures and technical results. This way, for example the German Patent DE 10309669 by VOLKSWAGEN AG (2004 ) that consists of a drying procedure for ultraviolet radiation of at least a layer of lacquer on a substratum where the lacquer layer contains at least a lacquer photoinitiated UV and where there is foreseen a step of previous drying along infrared radiation; as inventions that combine layers of varnish as the international Patent WO2005012816 by EISENMANN MASCHINENBAU ( 2005 ).In a more detailed way, by game of intervals of radiation UV and radiation of infrared beams and range of the beams, the North American patent US6528126 E.I. DU PONT OF NEMOURS (2003).
On the other hand the European patent n° EP1463589 of the same previous holder, E.I. DU PONT OF NEMOURS (2004) referred to procedure to retouch covered surfaces of substratum, where automotive mentions to painting repairs in the sector for the system of infrared radiation or "thermal energy" excluding the use of ultraviolet radiation and radiation of electronic bundle. Nevertheless, the use of infrared radiation in contrast to the ultraviolet radiation supposes a few major times of drying and a major thermal gradient with warming of the affected area.

Technical problem

The treatment procedures or treated by radiation UV of hardening and rapid drying of superficial recoverings of painting they are raised for his first painting of all kinds of materials or pieces (wood, metal, plastic, etc...). It is known that, which for repairs or corrections of defective parts, it is possible to repeat the process to obtain a similar finished product, but they suppose a few costs and times higher that becomes more expensive the final product. For it, there appears a specific treatment that does not suppose a repetition of the finished process of painting, but only of the affected area and of his immediate outline that is compatible with the rest of the identical piece fulfilling the requirements of quality and technical essays (tonality, shine, hardness, adhesion, elasticity, chemical resistance, etc ...) demanded for the finished piece, with internal character, for the manufacturers of the automotive sector.
The singularities of the automotive pieces shows that without a specific method, a study of thicknesses and stickiness of the applied product, not neither from the times of drying and ventilation, nor of the type of surface where it is applied, defects originate in the identical and finished products that suppose the detachment and flaked of the painting or varnish.

Technical solution

With a study and essays non-disclosed about the procedure used in automotive pieces, there is obtained a technical solution that allows the recovery of the defective pieces without need for the entire dismantling of the affected component and centring only on the damaged area. For it, it is necessary to present a method or treatment that by a radical way accelerates the drying processes, with the consequent advantages.
Usual and conventionally, the method or treatment of repair develops with the following phases: 1st).Detection of the defect. 2nd). Classification of the damage to turn off the piece (off line) or to repair on line (on line), 3rd) Preparation of the damaged surface. Dented damages leveling out,if necessary; 4th). Priming or application of basic coat, 5th) Drying of the basic coat by infrared beams or by drying with warm air; 6th) Sanded of the basic coat; 7th).Painting of the surface damaged and blurred of the area; 8th) Drying of the painting for infrared beams or for drying with warm air; 9th) Varnished of the surface repaired with lacquer; 10th) Varnished of the outline of the surface repaired with varnish dustcoat 11th) Ventilation of the varnish, 12th) Drying of the layer of varnish, for infrared beams, or for drying with warm air, 13th) Cooling off the area of repair (20-40 minutes), 14th). Polished of the repair area, and 15th).Restitution to area on line, or storage to area of repaired pieces.
In conclusion, along the whole repair process there are three stages where it is necessary to support a few drying interval times: Drying of painting, ventilation and drying of the layer of varnish, and cooling off the area of repair for his polished one. With this invention there are short interval times of drying of these stages by use of cured of beams ultraviolet, making unnecessary, in most cases, the dismantling of the piece damaged by the remarkable reduction of the temperature of drying.
According to the class of basic material (plastic, PP, ABS, PA, sheet, metals...) and dimensions of the located damage of the recovering, often it is not necessary to repaint completely the whole bodywork or component of the same one, for example a bumper. Not only there is obtained a more rapid and necessary simplified, but great system so much in the field of repairs of painting in workshops, but also in the finishing touches during the original recovering in the serial production line.
Simplified finishing touches procedures are known where without losing quality, there are obtained surfaces that are smooth and optically excellent with good resistance, satisfying the conventional requirements that are established with regard to the finishing touch of recoverings of vehicles, such as resistances to the dissolvers and to the alteration caused by the exhibition to the water and outdoors.
The ultraviolet radiation emitters can be located at a distance from 2 to 60 cm of the surface of the basic material to be radiated, and the ultraviolet radiation time can be, for example, from 5 seconds until 5 minutes.
Being adapted emitters of radiation the scale of wavelengths, in nanometres, between 50 and 750 nm, and preferably between 50 and 650 nm.
The distance between the issuing focus and the object can be, for example, from 2 to 60 cm, allowing the irradiation on three-dimensional geometries.The irradiation time can be, for example between 5 and 300 seconds. Referring to the duration of a continuous irradiation or to the sum of the periods of different cycles of irradiation. Looking between the different parameters for solutions so that we could avoid high superficial temperatures, as for example from 50 to 150 °C. Avoiding this way the harmful effects of the high temperatures, which prolong preferably the cooling stage for his polished later one of the retouched or repaired area.
The thicknesses of layer of recovering of the varnish of cured UV that are curable by means of ultraviolet radiation are applied in general in thicknesses of layer, in micrometers, from 10 to 1000 µm, and preferably from 10 to 250 µm.
It is possible, supporting the times of necessary ventilation, which the recovering film arranges more than a sole layer, being for example the application on a basic layer, to apply the layer or layers of transparent varnish for a later cured UV.
Also, could be necessary to avoid the stepped effects, to apply the varnish towards the rims, with a concentration in solids low, avoiding the encirclements, and to the one that we will define from now on as a dustcoat, for his biggest facility to the evaporation.
The recovering compositions can be watery or be diluted by a solvent or not to contain thinners does not even water down. In any solvent above mentioned case or water it must be eliminated during the ventilation phase. The compositions to which the present invention is related have to be photo-initiated and hardened for UV.
The layers of recovering that comprise a defective area to be retouched, can be considered to be habitual basic material formed by several layers, recovering of protection, cataphoresis, electrolysis, priming of putty and base layers, and in particular of the final layers of finished transparently to that the present invention shows.

Advantageous effects

This invention consists of three advantages, two functional ones and environmental other one. The first one, to functional effects with the use of the thicknesses previously mentioned in the diverse types of recovering achieves a drying in depth of the treated material, which provides a big power of adhesion of the varnish with the substratum or basic material, for the sake of the product quality, and of the procedures of technical standardization and industrial approval (UNE STANDARDS and ISO STANDARS RULES) in the sector of the automotive.
The second advantage focus on the type of weights and the used industrial process it facilitates his adequacy to the environmental regulations and of reduction of the Volatile Organic Compounds (VOC's), because it treats the motoring material with the use of solvents and volatile chemical compounds that are harmful to the environment ,and of a minor performance.
The third advantage and principal is the reduction of the time of drying and the possibility of being able to reach the phase of polished almost instantaneous, avoiding long periods of drying that allows the possibility of contaminations by dust or moisture.
By means of the following examples of tested essays, there are solved the following solutions by interval times of drying:

EXAMPLE 1

For a drying of printed putty, there get ready the UV-rays reflectors or heads at a distance between 500 mm of of the piece to repair with an emission of UV light covered between 350 and 450 nm of wavelength, obtaining a few times of drying covered between 50 seconds and 1 minute, from which the piece with putty drying can continue in his industrial process.

EXAMPLE.2

For a drying of UV varnish and dustcoat varnish, there get ready the UV-rays reflectors or heads at a distance between 300 mm of the piece to repair with an emission of UV light covered between 350 and 450 nm of wavelength, obtaining a few times of drying covered between 20 and 30 seconds minute, from which the varnished pieces can continue in his industrial process.

Description of Drawings

For a better comprehension of the general characteristics previously mentioned, a drawing is accompanied to the present invention which exhibits as there are specified next the finished phases of a process of repair, with the intervention of dried procedures:
Figure. 1 : 1st) Finishing touch of the surface Priming or application of a basic putty, 2nd) Drying of the putty printed by UV beams, or by infrared beams, or for drying with air; 3rd) Sanded of the printed putty; 4th).Painting of the surface retouched and blurred of the area; 5th) Drying of the painting by infrared beams or for drying with air; 6th) Varnished of the surface repaired with UV varnish; 7th) Varnished of the outline of the surface repaired with antifogging UV varnish; 8th) Ventilation of the varnish; 9th) Cured of the varnish layer using ultraviolet radiation; 10th) Cooling off area of repair (5-10 minutes); 11th).Polished of the repair area; and 12th).Restitution to area on line, or storage to area of repaired pieces.

Mode of the invention

The drying by ultraviolet radiation is performed by means of a few systems of UV-rays reflectors or heads arranged in the phases where it is operative between 100 mm and 1000 mm of distance to adapt itself to the three-dimensional shape of the piece to be repaired with an emission of UV light covered between 50 and 650 nm of wavelength. The above mentioned wavelength will be able to be reached using steam lamps of mercury and/or gallium, obtaining a few times of drying covered between 5 and 300 seconds.
The phases where the drying can be operative for radiation are: the phase of Drying of the putty printed by UV beams, or by infrared beams (2nd phase), the phase of varnished of the surface repaired with UV varnish (6th phase), the phase of Varnished of the outline of the surface repaired with antifogging UV varnish (7th phase), and the phase of cured of the varnish layer using ultraviolet radiation (9th phase).

Claims

Ultraviolet drying method for repairing paint defects in the automotive industry characterized because it consists of a drying phase of the putty printed trought UV-rays reflectors or heads arranged between 100 mm and 1000 mm of distance of the piece to be repaired with an emission of UV light covered between 50 and 650 nm of wavelength. This mentioned wavelength will be able to be reached using steam lamps of mercury, or alternatively gallium.
Ultraviolet drying method for repairing paint defects in the automotive industry characterized because it consists of a varnished phase of the surface repaired with UV varnish throught UV-rays reflectors or heads arranged between 100 mm and 1000 mm of distance of the piece to be repaired with an emission of UV light covered between 50 and 650 nm of wavelength. This mentioned wavelength will be able to be reached using steam lamps of mercury, or alternatively gallium.
Ultraviolet drying method for repairing paint defects in the automotive industry characterized because it consists of a varnished of the outline of the surface repaired phase with antifogging UV varnish throught UV-rays reflectors or heads arranged between 100 mm and 1000 mm of distance of the piece to be repaired with an emission of UV light covered between 50 and 650 nm of wavelength. This mentioned wavelength will be able to be reached using steam lamps of mercury, or alternatively gallium.
Ultraviolet drying method for repairing paint defects in the automotive industry characterized because it consists of a cured of the varnish layer phase throught UV-rays reflectors or heads arranged between 100 mm and 1000 mm of distance of the piece to be repaired with an emission of UV light covered between 50 and 650 nm of wavelength. This mentioned wavelength will be able to be reached using steam lamps of mercury, or alternatively gallium