DE2042778A1 - Insulating surface pretreatment coatings, processes for their preparation and their use - Google Patents

Description

DR. BERG DIPL.-ING. STAPF

PATENTANWÄLTE 8 MÜNCHEN 2, HILBLESTRASSE 2O

Dr. Berg Dipl.-Ing. Stapf, 8 Munich 2, HllblestroBe 20 Your sign Your writing Our sign

Attorney file 19 808
.Be / Sch

date

Aug 28, 1970

fiansburg Electro-Coating Corp. Indianapolis, Indiana 462o8 / USA

"Insulating surface pretreatment coatings, Process for their production and their use "

The present invention relates to a pretreatment coating formulation and a method of forming a layer of reduced toughness an insulating limited area (an Isolierbe-X'eic ti; or an insulating (overall) surface of a

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BATH ORIGINAL

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Large number of different types of substrate, which means that a protective and / or decorative coating can be deposited is facilitated on the substrate. In particular concerns the present invention provides a coating formulation including a binder and particles that reduced Resistance . when exposed to a suitable source of radiant energy. The present The invention also relates to a method for the electrostatic deposition of particles of a material for a protective and / or decorative coating on the coating preparation, carried by the insulating region or surfaces of the substrate is upset with them.

It is known that individual particles may be attracted to a Beschichtungsraaterials, such as color, for example, carry a charge of a nearby sub f strat having a potential which attracts the charged particles and may be characterized deposited thereon. In general, the substrate has earth potential.

The attraction of the charged particles of the coating material to the substrate results in a significant increase the amount of coating deposited on the substrate im Compared to a system in which air or other forces for atomizing and propelling particles of the coating ;; materials to define the surface. ,

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bath

intended material can be used. The use of air to atomize and drive coating material towards a substrate can result in coating material losses that can constitute 70% of the total amount of coating material dispensed. These losses occur, among other things, because the coating material moves past the substrate. The use of electrostatic processes to support the deposition of the coating material brings about a substantial reduction in material losses. The charged particles of the coating material scattered beyond the object tend to envelop it or to return in the direction of the substrate. The particles of the coating material that return to the substrate tend to deposit or become deposited on surfaces of the substrate that are not exposed to the immediate spray of the particles.

A system used to coat a nearby substrate with coating material is suitable, an apparatus should be provided which is capable of removing the coating particles to charge electrically with the desired charge and the electrically charged particles of the coating material brought to a position near the surface of the substrate whose coating is desired so, that the particles are deposited or deposited thereon

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can. The surface or surfaces of the surface to be coated intended substrate should or should have such a polarity that the charged coating particles attracted to and deposited on the surface or surfaces of the substrate.

Various devices atomize liquid coating material particles and charge them electrostatically .. The charged .Particles of the coating material are charged deposited on an electrically grounded surface or on electrically grounded surfaces of the substrate. That Coating material can be used as a liquid coating material be atomized by means of various different processes, for example by centrifugal, hydrostatic, electrostatic force, air, their combinations, and the like. It can also be the coating material particles be a non-liquid particulate material. The particles of the non-liquid coating material are fed to an electrostatic field that charges the particles electrostatically. In addition, it can electrostatic field the atomization of the liquid coating material assist or cause and the deposition of the charged particles either of the liquid or the non-liquid particulate coating material on the surface or surfaces of the sub-

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- Support or effect 5 strats.

The use of electrostatic processes to aid in the deposition of coating material particles on insulating surfaces or 'partial surfaces of a substrate that is to be coated, has little, if any Increasing the amount of deposition of coating material on the surface of the substrate in a system result in using forced air to propel the particles of the coating material toward the substrate used towards. In addition, there are various problems which, as such, are believed to be attributable to the electrostatic process which is used to coat an insulating surface with a coating material. So shows, for example, after a number of charged particles of the coating material on the insulating surface of the substrate, the coated surface has a charge polarity that is essentially the same Polarity is like the polarity of charge that the coating material particles hold exhibit. As a result, the atomized particles of the coating material tend to through the charge carried by the coating material particles already deposited on the insulating surface of the object is applied to be repelled, causing, inter alia, a loss of coating material and a Lack of uniformity in the thickness of the coating

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material deposited on the surface of the substrate is caused.

Efforts made in coating insulation areas or surfaces of a substrate using electrostatic methods to overcome problems, have led to the isolation areas or surfaces being pretreated with conductive solvents.

ψ However, the solvent containing the pretreatment preparation tends to impair the quality of the protective and / or decorative coating. In addition, the effectiveness of the preparation used to pretreat insulating surfaces appears to change as the solvent evaporates. In addition, the insulation surface can be adversely affected by the components of the pretreatment preparation. For example, the pretreatment preparation can throw up the wood fibers and plastic surfaces can be softened or loosened.

Other types of pre-treatment compositions tend to increase in the resistance at about 20 ⁰ C (7O ⁰ F) when the relative humidity of the ambient air at about $ 25 drops. The increase in the resistance of the pretreatment preparation at low relative humidities can lead to an incomplete

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coverage of an area or the surface of the substrate through the coating material. In addition, the properties of the pretreatment preparation can increase the strength the coating material to be deposited thereon. For example, the pretreatment preparation the electrical charge carried by the particles does not move at a sufficient speed unload; the deposited material then tends to retain a charge that is the same Has polarity like the particles of the coating material. but if the polarity of the deposited coating material is the same as the polarity of the particles, this leads to a repulsion of the subsequently arriving coating particles and a waste of the coating material.

The pretreatment coating formulation of the present invention can be used to provide a layer of reduced Resistance on an insulating area or surface of a substrate for the Purpose to create the electrostatic atomization deposition a protective or decorative covering material including liquids, such as paint, and non-liquids particulate materials such as thermoplastic or thermosetting Powder to make it possible. The substrates with insulating surfaces whose coating with the inventive

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proper preparation is intended to include, without limitation, Wood, cardboard, hardboard, glass, plastics and the like. "In addition, the pretreatment preparation according to the invention seal the surface of the substrate to which it is attached. The preparation is good Adheres to the 'substrate and forms a basis for the protective or decorative covering material.

It is accordingly an object of the present invention that hitherto in the coating of insulating areas or Problems encountered on surfaces of a substrate with electrically charged particles of a coating material to overcome.

Further objects of the present invention are:

- A pretreatment coating formulation for insulating areas or surfaces of a substrate which the areas

ψ or make surfaces susceptible to coating materials, which in turn are applied by electrostatic processes,

- a method of depositing a protective or sohmuck coating material on insulating areas or surfaces of a substrate using electrostatic processes,

- A composite (sandwich layer) object, the one Insulating surface, a pretreatment coating preparation, which is in connection with the insulating surface and

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ORIGINAL INSPECTED

a protective or decorative coating material that goes with the pretreatment preparation is in connection, has,

- a pre-treatment coating preparation for isolation areas or surfaces of a substrate that is essentially unaffected by changes in relative Humidity or the temperature of the surrounding air,

- a pre-treatment coating preparation for insulating surfaces or areas of a substrate that have reduced resistance when exposed to a source of radiant energy is exposed in such a way that it carries or conducts an electrical charge,

- a liquid or a dispersion material that is applied to surfaces in relatively thin layers can and turn into a solid coating after the passage of time changes.

These objects of the invention are achieved by uses a pre-treatment coating formulation that has a less resistive layer than about 2.5 x 10 ohms / cm on an insulating area or an insulating surface of a substrate. The resistance of the insulating area or surface of the substrate is larger than approximately

Qp

2.5 x 10 ohms / cm. The area or surface of the substrate that is covered by the pretreatment coating formulation can be electrostatically ^ri

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charged particles of a protective and / or decorative coating material be coated.

The preparation for the pretreatment coating of the The insulating surface can contain pigment particles which are activated in this way by a suitable radiation energy source are that they are an increase in terms of electrical

^ Have conductivity. The pretreatment preparation r

has good adhesion to the substrate and it provides the basis for the protective and / or decorative covering material. the Preparation can also seal the surface of the substrate.

The method for coating of the insulating or insulating surface of the substrate with electrically charged particles of the ßeschichtungszubereitung is that ψ the area or surface with the radiation energy-activated treatment composition providing and electrically charged coating material particles adjacent bzwο obvious the substrate available holds. Compared to the activated pretreatment coating preparation, the electrically charged particles have such a charge that the electrically charged particles of the coating material are attracted in the direction of the pretreatment coating preparation and are deposited thereon, whereby the substrate with the protective and /

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or jewelry coating is provided.

The insulating surface of the substrate, the pretreatment coating formulation and the coating material cooperate to form a composite (sandwich layer) article is formed.

The invention is explained in detail by the following drawings, wherein:

Figure 1 is an enlarged cross-section of a laoLieroberflache coated with the coating formulation of the present invention,

i'igur 2 shows an enlarged cross-section of an insulating surface which is covered by the coating formulation of the present invention,

Figure 3 is an enlarged cross-section of a composite made by the method of the present invention and

Sigur 4- an explanation of an electrostatic device is used to deposit the protective and / or decorative coating material can be used on the substrate with an insulating surface.

Generally speaking, the present invention relates to a pretreatment coating formulation used to do so a thin layer of reduced resistance

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Stability on an insulating area or an insulating surface of a substrate so that the area or surface covered with the pretreatment coating preparation is provided, electrically coated with charged particles of a protective and / or decorative coating material can be. The coating material can be either a liquid or a non-liquid material be.

The pretreatment coating formulation can be either a liquid or a dispersion material which Has particles generated by a magnetic radiant energy source to be activated. The activated particles show reduced resistance when they absorb the radiant energy have absorbed.

The method for coating the insulating area or the insulating surface of the substrate is that the Area or the surface of the substrate provided with the activated pretreatment coating preparation and the electrically charged particles of a suitable coating material adjacent to the surface of the substrate. The electrically charged particles of the coating material carry such a charge polarity with respect to the particles of the pretreatment coating preparation, that the electrically charged particles of the

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Layering material are caused to be attracted towards the coating preparation and deposited thereon to become, whereby the substrate is provided with the protective and / or decorative coating.

The insulating surface, the pretreatment coating preparation and the coating material cooperate to form a composite article.

For the purposes of this invention, surface resistivity is a suitable unit of measure to classify a substrate as either a conductor or an insulator because the unit is essentially independent of material dimensions. I ^{1 For} the purposes of the present invention, materials with specific surface area

resistances of less than approximately 2.5 x IO ohm / area (also called quare in American) and preferably

wise less than about 10 ohms / square as conductor and Materials with surface resistivities of approximately 2.5 x 10 ohms or higher are referred to as insulators.

The surface resistivity of all materials, including the consideration here surface of the substrate can be determined in a relative humidity of about $ 50 at a temperature of about 24 ° 0 (75 ⁰ F). The device used to measure the surface resistivity of the material including the substrate

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-charged circuit is a series-connected circuit comprising: a DC high voltage source with an output voltage of approximately 10,000 volts, a first aluminum cube approximately 1 inch (2.54 mm) on a side, with one of the sides of the cube attached to the The output of the high voltage source is connected and another side is connected to the insulating surface, a second aluminum cube 1 inch (2.54mm) on a side aligned with and approximately 1 inch from the first aluminum cube, one side of the second cube abutting the insulating surface to which the first alurainium cube communicates and an ammeter connected in series with the second aluminum cube. The high voltage source is operated to deliver approximately 10,000 volts DC to the series circuit. If the surface of the substrate intended to be coated with a coating material gives an ammeter reading of at least about 40 Alk , which after conversion to ohm / square is about 2.5 x 10 ohm / square, the surface is in a certain degree of electrostatic deposition of protective and / or decorative coating material accessible. However, the coverage of the coating material on the surface can be incomplete. However, if the surface of the substrate gives an ammeter reading of at least about 100 / UA, what

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after conversion: -in ohm / area is approximately 10 ohm / area, the surface is more suitable for the electrostatic deposition of the protective and / or decorative covering material.

A Darrholz panel was tested using the circuit set forth above and showed an ammeter reading of approximately 10 microamps, which when converted to ohms / cm is approximately Λ0 ohms / cm. A length of polyethylene, also tested on the circuit outlined above, had an ammeter reading of approximately 0 microamps. It is believed that, for the purposes of the present invention, materials with a surface resistivity of approximately 2.5 x 10 ohms / cm or greater of the pretreatment coating formulation should be coated.

To materials likely to be associated with the pretreatment coating formulation are pretreated prior to the application of the electrically charged coating material particles should include, without limitation, all types of wood, cardboard and hardboard, all types of glass, Glass sheets (flat) and glass fabrics and plastics such as chlorinated polyether, polyester, polyvinyl chloride, Epoxy, nylon and the like.

Referring more closely to Figure 1 of the drawing, a Precoat formulation 10 of approximately 0.4 micron star

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ke as an essentially completely covering insulating surface 11 'of the article 11 is shown »The insulating surface 11' can be made of any material, that has a surface resistance of approximately 2.5 x 10 ohm / cm or higher.

The pretreatment coating formulation 10 may be a liquid or a dispersion material which is applied in any suitable manner to the surface 11 'in relatively thin layers and which changes to a solid material over time. The change to a solid material may or may not be reversible and may be by evaporation of a suitable solvent or chemical reaction or a combination thereof. The Zuoereitung 10 usually contains a particulate or Pigraentmaterial 12, a binder 13 and a solvent (not shown), W controls the consistency of the preparation.

The pigment material 12 can mechanically interact with the treatment coating formulation 10 put together and, when the preparation dries, stored. The material 12 is general in its physical properties durcti the incorporation of the binder 13 or its Used deposit.

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The preparation 10 has sealing properties, adheres on the substrate 11 and forms a base for the protective and / or decorative covering material.

The pigment 12 should be suitable for activating, ie, ₀ have a state in which its resistance

Q p

less than about 2.5 x 10 ohms / cm and preferably

U p

is less than about 10 ohms / cm when exposed to a source of radiant energy. After activation, the pigment should be able to conduct an electrical charge. Various pigments which work satisfactorily are zinc oxide, barium titanate, indium oxide, cadmium sulfide, strontium chromate, and the like. Of the various pigments, zinc oxide is frequently due to its activation properties., Durability _r the protective character and the mechanical properties are preferred.

Generally a pigment like. particulate zinc. oxide activated to the extent when it is appropriately activated exposed to a suitable source of radiant energy. The pigment exhibits an increase in electrical conductivity (a decrease in resistance) when there is radiation emitted by the radiant energy source absorbed. The increase in the electrical conductivity of the segment can be achieved by means of various different Mechanisms depending on the type, the preparation and the

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Crystal formation of the coming into embossing pigment carried out will. The radiation necessary to activate the .figments can be in any part of the spectrum of visible light to x-ray or V-rays. That Pigment can be photoconductive, for example zinc oxide usually limitedly affected when exposed to ultraviolet light. However, some can be particulate Zinc oxides with a special crystal structure are activated by means of ultraviolet light and thereby their resilience to less than approximately

S?
10 ohm / cra lower.

Zinc oxide with a crystal structure that is opposite to ultraviolet Light is sensible, can be produced be that 99> 99% pure zinc is melted in a "French furnace", the zinc evaporates and the product burns with the formation of zinc oxide. The zinc oxide made using the "French Furnace Process" generally has an average particle size of about 0.37 microns. The chemical composition of such Particulate zinc oxide looks about 99% Wt.; O zinc oxide (ZnO), 0.002 wt. ^ Lead oxide (Pb), 0.0004 wt. / O Cadmium Oxiä (OdO) and opures of Lisen, copper, silver, Chromium, tin, calcium, kagnesiuin, silicon and anaeren Materials to be.

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BATH ORIGINAL

The zinc oxide produced by the French furnace process should have an average particle size of 1 Ai or less, preferably ungefähr.0,5 / U or less, and in particular an average particle size of about 0.4, u or less.

A suitable source of radiant energy for converting the particulate zinc oxide from a normally non-conductive structure to a structure capable of conducting an electrical charge by reducing the resistance of the zinc oxide is a light source. A suitable light source can be an ultraviolet ray emitting light source. Ultraviolet lights are those rays in or just outside the visible spectrum at its purple end and they are more easily breakable than purple strands. The wavelength of the ultraviolet rays are generally in the range of about 120 to about 4,000 L ·

Line coating preparation 10, which contains a pigment, which in turn contains particulate zinc oxide, which under Using the French oven process and an average particle size of approximately 0.40 / U, appears sufficiently through ultraviolet otblast with a length of about 3600 to about 3Ö0u α and through rays with a wavelength of

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about 5000 to about 6000 S. to be activated ► However, it appears that other inorganic pigments are sufficiently activated by other light sources, such as light, photo headlights, mercury light, and the like. If particulate zinc oxide is dispersed in some binders, it seems _t that normal room light "no satisfactory wavelength and intensity has to the particulate zinc oxide to activate sufficient so that its resistance is decreased to the point, which makes it sufficient for the intended according to the invention Purposes becomes conductive.

Before it is applied to the surface 11 'and before drying on the surface 11', the binder 13 contains a resin component and it may further contain a solvent component. The resin can be organic or inorganic material, either natural or synthetic in origin. The resin should be low or have no tendency to crystallize. The resin used is generally transparent or translucent, has a resistance of approximately 2.5 χ 10 ohm / cm or higher and is in most organic solvents soluble. Further desirable properties of the binder are: Adhesion or gluing to the insulating surface 11 ', moisture resistance, ability with an overlaid surface or metireren

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BATH

Layers of protective and / or decorative cover material to be coated, low viscosity while it is applied to the insulating surface, no disturbing Influence on the activation of the pigment by the A source of radiant energy and having an acid number which prevents it from adversely affecting the pigment implements. To various resins that act as binders can work satisfactorily in preparation 10 without limitation to these nitrocellulose (cellulose nitrate), cellulose acetate butyrate, vinyl resins, alkyd resins, Epoxy resins, acrylic resins, polyesters, melts of plastic materials and the like can be mentioned.

The solvent that can be mixed with the resin is primarily used to lower the viscosity of the resin so that the application of formulation 10 on the insulating surface 11 'is facilitated. The solvent is used, among other things, to control the consistency of the coating preparation 10 and during their application to the insulating surface 11 * to facilitate. Controlling the consistency of the -t coating preparation 10 improves the application properties of the preparation on the insulating surface 11 '. The solvent Should be during the drying of the coating preparation 10 evaporate on the insulating surface 11 '.

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BAD ORlQlNAL

Suitable solvents for nitrocellulose are, for example Esters such as ethyl acetate, hexyl acetate, butyl acetate, methyl acetate, alcohols such as toetnyl alcohol, ketones such as acetone, Diethyl ketone, ethyl amyl ketone, ethyl butyl ketone and the like. Suitable solvents for cellulose acetate butyrate are, for example, esters such as butyl acetate and ethyl acetate and methyl acetate, chlorinated solvents such as carbon tetrachloride, dichloroethyl ether, ketones such as acetone and cyclohexanone and the same. Suitable solvents for vinyl polymer or copolymer resins such as polymethyl, methacrylate, polystyrene, polyvinyl chloride and the like are, for example, chlorinated hydrocarbon solvents such as carbon tetrachloride, dichloroethyl ether, ketones such as acetone, diethyl ketone, ethyl amyl ketone, ethyl butyl ketone and the same. Suitable solvents for polyesters are, for example, aromatic hydrocarbons such as Benzene, toluene, xylene, esters such as ethyl acetate, hexyl acetate, methyl acetate and the like.

The binder can be suitable epoxy or polyester resins and suitable extenders such as monomers that add to the use of solvents with the binder seem to achieve the desired viscosity of the binder during application to the surface 11 ' contain. In addition, melts of material such as plastics can be used as a lead in the event that

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BATH ORIGINAL

the addition of solvents to the binder to achieve the desired viscosity does not seem to be necessary.

The pigment i2 is randomly in a suitable one Binder 13 dispersed. The pigment to bandage ratio Agent in formulation 10 should range approximately from about 1: 3 to about 6: 1. In the coating preparation 10 is a satisfactory pigment to binder ratio of about 1: 3 to about 1: 1, a ratio of about 1: 3 being particularly satisfactory is to be seen. The upper limit of the pigment-to-binder ratio, i.e. 6: 1, is to some extent achieved by the desired adhesive, sealing and sealing The viscosity properties of the preparation are limited. A pigment to binder ratio below about 1: 3 provides a preparation with unsatisfactory properties.

The pigment of the coating preparation includes at least a-. Pigment produced by a radiant energy source is activated and it may contain a pigment which is substantially unaffected by the source of oil energy is. The asfciv-i er th pigment is then that part of the total pigment the one otromweg with a lowered vVid Resilient-Kuit (higher conductivity) in the preparation.

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That. Ratio of the pigment produced by a radiant energy source & urch Radiation can be activated to make the pigment, which is essentially in the radiant energy source remains unaffected should be at least about 1: 9. The pigment of the preparation can be made entirely of material exist, which can be activated by radiation from the radiant energy source.

That part of the pigment which is essentially carried by the strah_ tion energy remains unaffected by the source, an extender can be used. The extender can be used in order to increase the mass of the coating preparation and thus the costs without adversely affecting the To lower the activation property of the coating preparation. Particulate barium sulfate, calcium sulfate, calcium carbonate, Silica, kaolin clay, magnesium silicate, mica, and the like can be used as an extender will. The particle size of the extender should match the particle size of the pigment that is suitable for activation is to be compatible.

To improve the sensitivity of pigment 12 in certain visible and invisible areas of the spectrum Or to increase color sensitizers like Acridine Orange, Fluorescein, Eosin Y, Rose Bengal, Methylene Blue and the like can be mixed with the pigment.

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The coating formulation 10, which is a pigment; to binder ratio contains from about 1: 3 to about 6/1, has individual pigment particles that are in contact with neighboring pigment particles.

It can be assumed that the thickness of the coating preparation 10 after application and drying on the insulating surface 11 'need not be greater than the thickness of a single particle of the pigment 12. The thickness of the coating preparation 10 therefore does not have to exceed the average particle size of the pigment . It can be assumed that the particle size of the pigment represents the lower limit of the strength of the dried coating preparation 10. For example, the lower limit of the thickness of a dried coating formulation 10 containing particulate zinc oxide can be approximately 0.4 ai . In contrast, using conventional application techniques such as spraying, dipping, brushing, rolling, tumbling, and the like, generally a layer of coating formulation 10 about 6 to about 25M (0.2 to 1 mil) thick is obtained. In this case, no upper limit can be set with regard to the thickness of the dried coating preparation 10 on the insulating surface 11 '. However, if the strength exceeds about 25 / U, no tangible benefit will be achieved. Of the various procedures used to

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Application of the coating preparation 10 to the insulating surface 11 'can be used is spraying atomized particles of the preparation onto the surface 11 'more advantageous than dipping, as spraying deposition of a relatively uniform layer of the preparation on the surface 11 '.

The coating preparation or the coating 10 can be dried on the surface 11 'by air drying or by heating the preparation to an elevated temperature. A suitable elevated drying temperature is about 50 ⁰ O (125 ⁰ If ¹ ) with a drying time of about minutes. As the drying temperature is decreased, the drying time increases.

The one used to measure the surface resistance of kiln wood The electrical circuit used is also used to measure the surface resistance of an activated coating preparation 10, which contains zinc oxide pigment and a nitrocellulose binder, was used. The pigment too The binder ratio of the coating formulation is approximately 1: 3. The ammeter reading is approximately 850 Microamps, where the converted surface resistance is approximately 12 X 10 ohms / flat. The change in The temperature and moisture content of the air surrounding the preparation or coating 10 appears to be very low, if any, an effect on the resistance of the

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-27 preparation to have "

FIG. 2 is an enlarged illustration of the coating preparation 10 which is applied to the surface 11 '. The thickness of the coating formulation or coating 10 is approximately 25 ax (1 mil). The various components shown in Figure 2 are not shown to scale; therefore, one of the components shown in Figure 2 may be enlarged more than other components of the figure The coating preparation 10 includes a binder 13, such as nitrocellulose, in which particles of the pigment 12, such as zinc oxide, are randomly dispersed. The coating preparation or coating 10 as applied to the insulating surface 11 'also includes one suitable solvent which is intended to reduce the viscosity of the preparation and thereby improve the properties of the preparation on the surface 11 '.

In Figure 4, a coating approximately 0.025 mm thick of the preparation 10 is applied to the surface 11 'of the substrate. Conventional methods such as spraying, dipping, Brushes, rollers, spatters and the like can be used to apply the preparation 10 to the surface 11 ' will. The solvent is removed from the preparation by a suitable drying step.

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A suitable radiant energy source 16 is used to activate the pigment. The surfaces of the substrate 11 are exposed to the influence of the activation source 16 so long that the pigment 12 before it is in close proximity Proximity to the disk 25 is sufficient is activated.

In the figure 4, one of different types is now ψ of electrostatic devices that can be used to coat the substrate 11 with the Beschichtungsraaterial 14, explained in more detail. A conveyor device 20 has conductive holders 21 which transport a plurality of substrates 11 on a semicircular path around an atomizing device 22. The atomizing device 22 can be mounted for vertical up and down movement on a support which is designated in its entirety by the reference numeral 23.

The upper end of the up-and-down movement device has a rotor 24 that supports the atomizing device 22 carries, for example, a thin, substantially flat circular disc 25 made of a suitable sheet metal can be. An opening 26, approximately in the middle of the upper surface of the disc 25, is for a coating material pump 27 connected, the coating material 14 stripped from the container 29 and applied to the upper surface

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- 29 of the disc releases.

The conveyor 20 and the brackets 21 are grounded (The formulation or coating 10 carried by the substrate 11 is electrical via the supports 21 and the conveyor 20 · connected to earth) and the atomizing device 22 is at a high electrical potential with respect to ground by a suitable DC power source 50, which is connected to the atomizing device 22, held. The DC power source is suitable, the disk 25 of the atomizing device 22 to to supply approximately 90,000 volts DC.

The substrates 11 are thereby transported by the conveying device moved around the atomizing device 22 in an arcuate path (crossing a semicircle). It is to be noted that the substrates 11 are arranged at a distance radically outward from the sputtering device 22 and the plane of rotation. Therefore, the electrical force that exists between the atomizing device 22 and the grounded substrate causes and a centrifugal force acting on the coating material 14- is exercised when · when it is on the upper surface of the Disk 25 moved out and atomized from the edge of the disk is so that the atomized and charged material 14 is directed outwardly towards the substrates 11. During the movement around the sputtering device 22, the substrates can if they are sufficiently symmetrical

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are to be determined by the holding device 21 ″ Axis are rotated so that the substrate is exposed to several whales of the action of the sputtering device 22 is.

The activated formulation 10 causes the deposited particles of the coating material to be charged with is dissipated to earth at sufficient speed, "so that no polarity occurs in the substrate in the sense that that subsequently arriving coating particles are repelled by the deposited coating particles Any cargo carried along is discharged to the ground via the holding device 21 and the conveying device 20.

It is thus possible to apply a suitable protective and / or decorative coating 14 on a coating preparation or a coating 10 which has been activated by a suitable radiant energy source 16, as shown in Figure 4- with the formation of a composite material £ shown in FIG 17 to deposit. The coating material 14 is applied to the activated preparation 10, whereby it can be seen that an activated pigment, such as zinc oxide, provides such a resistivity that at least a portion the electrostatic charge that the particles of the deposited coating material 14 entrain, removed via them The initial layer of the coating material 14 can be deposited on the substrate 11 to a thickness of approximately 0p25 πηβ.

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stored and air dried. It can be over the initial layer of coating material 14, two additional layers of coating material, each with a thickness of about 0.025 mm using electrostatic Procedure are applied.

The following examples explain the application of the preparation to the surface of a kiln wood substrate by activating the pigment of the preparation and the Deposition of coating material on the preparation.

example 1

About 100 grams of particulate zinc oxide, prepared by a process using the "French oven" and having an average particle size of about 0.4 Ai , is ball milled with about 85 grams of nitrocellulose varnish for about 4 hours. The nitrocellulose content of the paint is about 20 wt. # Or about 17 g. The mixture produced with a ball mill is diluted with butyl acetate to a viscosity of approximately 20 in a Zahn Cup Kr. 2. The diluted mixture is sprayed onto the surface of the wooden board to such an extent that the surface is covered by the diluted mixture. The wood board is heated minutes at a 'i'eraperatur of about 50 ⁰ G ⁽⁰ 125 S ¹⁾ about JO to the solvent from the mixture to

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volatilize and with it the preparation or the coating to manufacture. The coated wooden panel is exposed to ultraviolet light, which is sufficient for the zinc oxide activated. For this purpose the one covered with preparation 10 is covered Wooden surface with its front facing an ultraviolet light source and at a distance of held approximately 30 cm (1 foot). The coating preparation is exposed for about 10 to about 20 seconds or longer. The preparation 10 or the coating is included Connected to earth. It becomes an electrostatic device which is connected to a DC power source supplying approximately 90,000 volts and it becomes a gap of the plate from about 30 to about 40 cm (12 to 15 inches) is used for the electrostatic application of the protective and / or decorative coating material 14, where this is about 0.025 rome thick after coating preparation having.

Example 2

Approximately 100 g of particulate zinc oxide, produced using the "!""Ranzösischenfurnace" process and with an average particle size of approximately 0.4λι, is approximately 4 otunden in a ball mill with approximately 243 g of vin ^ ltoluene alkyd resin (KLaskon 3ÖO1-5OX) mixed. The alkyd content of the resin is about 70% by weight , or about 170 g. The product made in the ball mill

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is mixed with toluene to a viscosity of approximately Testify diluted in a tooth Gup No. 2. That diluted Mixture is sprayed on the surface of a kiln board, dried and coated with the coating material according to the method of Example 1.

Example 3

About 100 grams of particulate zinc oxide, prepared using the "French Oven" process and having an average particle size of about 0.4 Ai , is ball milled with about 85 grams of nitrocellulose (cellulose nitrate) (bottom seal) varnish "for about 4 hours mixed. the cellulose nitrate content of the lacquer is about 20 wt.% or about 17 S · the manufactured by means of ball mill mixture is diluted with butyl acetate to a viscosity of about 20 seconds in a Zahn Cup-Kr. 2,. the diluted mixture is subjected to the surface Dried wood panel sprayed, dried and coated with the coating material according to the method of Example 1.

Example 4

Approximately 1000 g of particulate zinc oxide, produced under Use of the method using an "i'ranzösisctien Oven "and with a mean particle size of about 0.4, u is ball milled with about 340 g

1098 53/162 3

Acrylic resin (Ashland Ghem. Co. 5208'1'5O) approximately 4 hours mixed. The acrylic resin content of the resin is 52001'5O about 50 w / y or about 170 g. That by means of a ball mill The mixture prepared is measured with toluene to a viscosity of approximately 20 in a Zahn Cup ilr. 2 diluted. The diluted mixture is sprayed onto the surface of a Darrholzplatte, dried and mic ^ escnicn.-processing material coated according to the procedure of Example 1.

Example 5

Approximately 100 g of particulate zinc oxide, manufactured under Use of the process with the "French Oven" and with an average particle size of about 0.4, u is ball milled with about 17 g otyrolbutadiene resin (Pliolite b-5-B) mixed for approximately 4 hours. That means Mixture made by ball mill is calibrated with toluene to a viscosity of about 20 in a Zahn cup Wr. 2 diluted. The diluted mixture is applied to the surface a Darrholzplatte sprayed, dried and coated with the coating material according to the method of Example 1 coated.

Example 6

About 100 grams of particulate zinc oxide made using the "French furnace" process and having an average particle size of about 0.4 , u.

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BATH ORIGINAL

is mixed with about 215 g nitrocellulose (Celluloseni-crat) varnish using a ball mill for about 4 hours. The cellulose nitrate content of the lacquer is about 20 wt.%, Or about 42.6 g. The mixture prepared by means of a ball mill was diluted with butyl acetate to a viscosity of approximately 20 seconds in a tooth Gup No. 2. The diluted mixture is sprayed onto the surface of a kiln board, dried and coated with the coating material according to the procedure of Example 1.

Example 7

about 100 -g of particulate material made up of about 10 g of zinc oxide, made using the "Transösischer Oven" process and with an average particle size of about 0.4-yU, and about 90 grams of titanium dioxide contained, is in a ball mill with about 213 g of nitrocellulose-COellulosenitrat ^ lacquer for about 4 hours mixed. The gelulose nitrate content of the lacquer is approximately 20% by weight or approximately 4-2.6 g. That by means of a ball mill produced mixture is with üutylacetat on a Viscosity of about 20 seconds in a Zahn Cup Kr.2 diluted, the diluted mixture is applied to the surface sprayed on a Jarruoli plate, dried and covered with the Beseiiicrituagsuaterial after following Example 1, bes chic ht et. -.- ■ '-.

'ι ÜB 86 3/1623

Example 8

Approximately 100 g of particulate strontium chromate with an average particle size of approximately 1 / rev is mixed with approximately 68 g of vinyl toluene alkyd resin (Plaskon 38O1-5OX) for approximately 4 hours using a ball mill. The Alkydharzgehalt of the resin is about 70 wt.%, Or about 48 g. The ball mill mixture is diluted with toluene to a viscosity of approximately 20 seconds in a # 2 Zahn Cup. The diluted mixture is sprayed onto the surface of the wooden panel, dried and coated with the coating material according to the method of Example 1.

Example 9

Approximately 16 g of particulate zinc oxide, prepared by the "French furnace" method and having an average particle size of approximately 0.4 · Ai and approximately 90 g of extender containing 45 g of Abestine 5X, 34 g of kaolin and 11 g of calcium carbonate, are mixed in a ball mill with approximately 68 g vinyltulol alkyd resin (Plaskon 3801-50X) for approximately 4 hours. The alkyd resin content of the resin was about 70% by weight or about 48 g. The mixture prepared by means of a ball mill is diluted with toluene to a viscosity of about 20 times in a No. 2 tooth Gup. The diluted mixture is sprayed onto the surface of a Darrholzplatte, dried and with

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109853/1623

20A2778

the coating material according to the method of Example 1 coated.

The following tables explain some properties the dried coating preparation 10 containing a pigment (zinc oxide) to Binder ratio of approximately 6: 1 having.

The above-described current circuit for measuring the surface resistance of the insulating surface 11 ″ of the substrate 11 is also used to measure the surface resistance of the coating preparation 10 after it has been exposed to room light and photo light. the ütromkreis described above is also used for measuring the surface resistance of the ßeschichtungszuüereitung after this had exposed by photo light under different relative humidities at about 20 ⁰ C (JO ⁰ I?). the surface resistances of the coating composition 10 are given in Table II.

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10 9853/1623

_ 38 -

■ fabeile I

Photosensitivity
Resin type (binder) room light, photo light

otyrolbutadiene (Pliolite Ü-5B)

Vinyl toluene alkyd resin (Plaskon)

readings in X 1Ü ^Ö οhm / area) X 10 ⁷ 2.5 X 10 ⁷ 3 2.5 X 10 ^Ö K X 10 ⁷ 1.3 X 10 ⁸ 2 »3 χ 10 ⁷ 2.5 X 1O ^Ö 3, , 5 χ 10 ⁷ 1.3 2,

High acrylic acid resin
(Ashland Ohem. Go.3208T 50)

Nitrocellulose (LAck)

Nitrocellulose (pore closure) lacquer

Table I shows that the degree of activation of the zinc oxide in room light varies with use Types of binders changes. The coating preparation 10, which uses a pigment (zinc oxide) to form a binder (Vinyl toluene alkyd resin) ratio of about 6: 1, appears to be sufficiently activated by room light, the advantageous use of electrostatic deposition processes to deposit the coating material 14 on these, while the other zinc oxide and resin combinations are not sufficiently activated by room light in the sense that the covering of the coating material can become incomplete when using electrostatic processes. Everyone will Pigment (zinc oxide) and binder (resin) combinations are sufficiently activated by photo light so that electrosta-

-39-109853 / 1623

Table methods for depositing the coating material 14 can advantageously be used.

Table II Effect of Moisture

feu 209b

Resin type humidity at around 20 0

(Readings in οhm / area)

iStyrene butadiene ₉ π π

(Phiolite S-5B) 3 χ 10 ^/ 3x10 '. 3 χ 10 ^Λ

Vinyl toluene alkyd resin ₉ r-, / ₇

(KLaskon 38O1-5OX) ^10/10 '10'

Resin with high acrylic acid content (Ashland Chem. Go. Ι "ι π 3 ^ ϋ8ΐ 50} 2.5 χ 10 '2 χ 10' 2.5x 10 '

Nitrocellulose (lacquer) 3.5 χ 10 ^ 3.3 χ 10? 3.3 10 ^ rJitrocellulose (closure) - "' _r . _n Paint 2.5 χ 10 '2.5 χ 10' 2 χ 10 '

Lie i'abeile 11 shows that the surface resistance of the Layering preparations 10 are not disadvantageous due to modifications is affected in the relative humidity of the surrounding air.

i) The present invention is not obscured by the description limited, since changes and modifications can be made by those skilled in the art without departing from the spirit of the invention.

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109853/1623

BAD OBlGiNAU

Claims (3)

Patent claims: 1. Isoiier surface pretreatment characterized by the fact that they are a pigment that can be activated by eme radiant energy and as a result, has a reduced resistance to dissipate an electrical charge, and has a binding agent, in which the pigment is dispersed, the .binder is substantially chemically inert with respect to the pigment and has properties such that the pigment maintains reduced resistance after removal of the radiation energy source. 2. Insulating surface pretreatment coating formulation according to claim 1, characterized in that the binder contains a resin and a solvent. ψ 3. Insulating surface pretreatment oil coating preparation according to claim 1, characterized in that the binder contains a resin. 4. Insulating surface pretreatment coating preparation according to claim 1, characterized in that the pigment-to-binder ratio is at least approximately Λ '.' Ό . 1 ü 9 8 5 3/1 6 2 3 5. Insulating surface pretreatment coating ready according to claim 3, characterized in that the pigment contains a metal oxide. 6. Insulating surface pretreatment coating preparation according to claim 5, characterized in that the metal oxide contains zinc oxide. 7. Insulating surface pretreatment coating formulation according to claim 6, characterized in that the binder contains nitrocellulose. 8. Insulating surface pretreatment coating formulation characterized in that it is a pigment suitable for activation by a source of radiation energy and thus has a reduced resistance so that it can and continues to conduct an electrical charge the pigment essentially by the radiant energy source remains unaffected and contains a binder in in which the pigment is dispersed, the binder being essentially chemically inert with respect to the pigment and the properties of the binder are such that the pigment maintains reduced resistance after removal of the radiant energy. 9. Insulating surface pretreatment coating accessories 109853/1623 Preparation according to claim b, characterized in that -icu the ratio of pigment which is activated by the radiation energy source to rigment, which essentially remains unaffected by the radiation energy source, is approximately 1: 9. Riding according to claim 9 by using the code number: / c, because, uas W Ratio of Ue including tu en ge ± 'igraeut to uinaeuiiktel at least about 1: 5 11. A method for .ablagerung of articles ^ ^ in it OAER uchrauckbescnichtungsmaterials a isolierteilfläcne OAER on the surface over a oubstrats, including one versient the i'eilchen a besenicauungsmateri ^ is zi ± v einor charge charged reilcnen SiCN on aio Isolierteilfläche or The surface of the substrate can be moved and the particles of the coating material deposited on the substrate, characterized in that the insulating part surface or surface is provided with a pretreatment coating preparation which contains an electrically conductive pigment, the particles having a pigment with respect to the pigment, before the particles are charged Have polarity, themselves
which causes them to move in the direction of the pretreatment preparation to move and to deposit on it. 109853/1623 12. The method _o 'eraäß ai ^ i.tucu 11 characterized in dai .. mau the resistance reduced by the pigment, to the Juis subjecting a btranlungsenergiequelle l'eilciien. 13. Procedure for .besciiiciitunt-. of a substrate with a electrical insulating surface characterized in that a pretreatment coating preparation is placed on the insulating surface of the substrate which contains a pigment that is activated in such a way that it reduces a ., has resistance in order to dissipate an electrical charge and you can see the electrically charged particles in feasibility or in comparison to the insulating surface, which carries the pretreatment coating formulation, brinrct, wherein the electrically charged particles a opposite charge in relation to the activated one have pigment, the electrically charged particles become iodine be assessed on the pretreatment coating preparation au to wander and to be deposited on it, wouurcii die .JuschiciituUt; of the substrate takes place. 14. Verfahret: -yeuiais claim Λ'ο characterized in that the pigment is made conductive in a further stage, for which purpose it is subjected to a source of transferring energy. 15 · ancestors {. Each claim 14 is characterized by ■ 109853/1623 _ 44 - that a light source is used as a source of radiation energy. 16. The method according to claim 14, characterized in that a metal oxide is used as the pigment. 1'7 '. Method:? S according to claim 1b, characterized in that that zinc oxide is used as the metal oxide. 18. The method according to claim 1j5, characterized in that that in a further process step the pretreatment coating preparation ground before you connect the eleK.-triscn charged particles in neighboring areas or in comparison brings to the preparation. 19. bystem for the electrostatic application of a coating material on an electrically insulating surface of an oubstrats by the fact that it (1) A device for applying a thin layer of a pretreatment coating preparation to the surface of the substrate, the preparation containing a photoconductive pigment and a binder, and on the The surface of the substrate adheres and seals it, (2) a device for suspending the preparation, a Light source, whereby the pigment after absorption of the otrah-J.ungsenergie becomes electrically conductive, 1ÜU8S3 / 162 3 BATH (3) a device for connecting the pigment to one electrical potential and (4) a device for creating particles of the coating material, that is charged with a different potential than the pigment, in the vicinity or opposite to the preparation, whereby the particles are attracted to and deposited on the preparation. 20. Composite material consisting of a) a first »layer of an insulating surface, b) a second layer over the insulating surface of the first layer, the second layer contains a pigment which is so activated that it exhibits reduced resistance and c) has a third layer over the second layer, the third layer contains particles of the coating material which are suitable to be electrically charged. 21. Bandage material according to claim 20, characterized in that the second layer is essentially completely covers the insulating surface of the first layer and the third ochicht essentially completely the second ochicht covers. 22. Composite material according to claim 20, characterized in that that the surface resistance of the insulating surface -46- 109853/1623 BAD 2lU? 778 2.5 x 10 ohm / iT'lucue or horier iou unci the waiter fIaciienv / resistance of the second οcnot about 2,> χ ΊΟ ear area or less. 23 · composite files according to claim 20 net that the iri ^ ment contains a lhecal oxide 2M-. Verbunarnatericii geiaa.ij Claim 'd'j dadurcn nec, dais das i-Ieualloxiu ^ inkoxia entsülb. 25 · composite material according to arisprucn 20 dadurcn - <er ^ n-AZeic 11- net, darö the second tichicut still an ir-i _b uieut: euthiilt, which is essentially unsuitable to be activated / grounded. 26. I / erbundmaterial according to u.nsprucn d'o daüurcn ^ ei: indicates that the ratio of activated pigment to non-activated pigment is at least about 1: y. the ratio of total weight i'igment to x3inäemit "oil is at least about 1: 5. 27. Composite material according to claim 26 is indicated that the second layer has a temperature of roughly ¹ 1/2 to about 0.025 mm or more. 28. Method for the electrostatic application of a coating material on an electrically insulating surface -47- 109853/1623 BATH ORIGINAL • ..- inυs, .lUiJotK'Cj jcHiarcii, VijkennzoxGnnet, aar ,; one on the ■ uerj'l'iotifc ..! to y.ibsurvti .: a thin ociiicht of a byi-iiiului-j.-ebosci-iunbunj.-ysuaereitun ^ 'who puts on a photo-1: iitfani res i-xyiiieiib urw contains a rjindeuiötel, wherein the. ■ .vibereitun. liable · a ^ u 'on the surface dec substrate and ti ■ sealed senergieruiretzt Hu ^ ^ ereitun Ui-v ^ a otrahlun that Pii.'weht v.'odurca na cn absorbing the suner ^ ie eleKtrisch le it 1'aiii g, the i-iä'ment uix.ό couples to an electrical potential and particles of ^ eGcnieutan-jüüimaterial, which have a different potential than u3s a-livni-eiit, are loaded in the neighborhood; or opposite, • üellun ;; brings to the preparation, viouurcn the particles are attracted by the preparation and abi, -ela _fc ; ert on the preparation. BATH 1 U9-85 3/162 3