MXPA00003089A - Flash evaporation of liquid monomer particle mixture - Google Patents

Abstract

The present invention is a method of making a first solid composite polymer layer. The method has the steps of (a) mixing a liquid monomer with particles substantially insoluble in the liquid monomer forming a monomer particle mixture;(b) flash evaporating the particle mixture and forming a composite vapor;and (c) continuously cryocondensing said composite vapor on a cool substrate and cross-linking the cryocondensed film thereby forming the polymerlayer.

Description

INSTANT EVAPORATION OF A LIQUID MIXTURE OF MONOMERIC PARTICLES FIELD OF THE INVENTION The present invention relates, in general, to a method for producing composite polymer films. More specifically, the present invention relates to the production of a composite polymer film, from a mixture having insoluble particles (conjugated or unconjugated) in a liquid monomer. Additional layers of polymer or metal can also be added under vacuum conditions. As used herein, the term "(meth) acrylic" is defined as "acrylic or methacrylic". As used herein, the term "cryogenically condensed" and forms thereof, refers to the physical phenomenon of a phase change, from a gas phase to a liquid phase, when the gas makes contact with a surface having a temperature. less than a gas dew point. As used herein, the term "conjugated" refers to a chemical structure of single and double bonds, alternated, between carbon atoms, in a chain of carbon atoms.

BACKGROUND OF THE INVENTION The basic process of flash evaporation is described in U.S. Patent No. 4,954,371 incorporated herein by reference. This basic process can also be referred to as instantaneous evaporation of multiple polymeric layers (MCP). Briefly, a polymerizable and / or crosslinking material is provided at a temperature below a decomposition temperature and a polymerization temperature of the material. The material is atomized to form small droplets having a size ranging from about 1 to about 50 microns. The small droplets are then evaporated, under vacuum conditions, upon contact with a hot surface above the boiling point of the material, but below the temperature that would cause the pyrolysis. The vapor is cryogenically condensed and then polymerized or cross-linked as a very thin polymeric layer. However, many electronic devices require composite polymeric layers for devices that include, but are not limited to, mol ecularly altered polymers (PMA), electroluminescent polymers (PEL), and electroluminescent electrochemical cells (CEL). Currently these devices are manufactured by centrifugal coating or physical vapor deposition (DFV). Physical vapor deposition can be either by evaporation or by cathodic spraying. In the centrifugal coating, the coverage of the surface area is limited and scaling to large surface areas requires multiple units in parallel instead of larger individual units. In addition, physical vapor deposition processes are susceptible to leaving small holes in the surface. In all of these methods of the prior art, the initial monomer is a (meth) acrylic monomer (Figure Ib). When Rx is hydrogen (H), the compound is an acrylate and when R-_ is a methyl group (CH3), the compound is a methacrylate. If the R2 group that hangs in the group (met) acrylate, is completely conjugated, the 0-C-bond interrupts the conjugation and makes the monomer non-conductive. Exposure to electron beam or UV radiation in the presence of a photoinitiator initiates the polymerization of the monomer by creating free radicals in the double bond (C = C) in the (meth) acrylate bond. After polymerization, the two double bonds (C = C) of the (met) acrylate, where the crosslinking occurred, they have become simple bonds (C-C). In this way, the crosslinking step further interrupts the conjugation and makes the conductivity impossible. Therefore, there is a need for an apparatus and method of high deposition rate, to produce composite polymeric layers, which can be scaled to cover larger surface areas, with a single unit, and which is less susceptible to the formation of small holes There is also a need for a method to preserve the monomer conjugation.

SUMMARY OF THE INVENTION The present invention is a method for producing a solid, first composite polymer layer. The method comprises the steps of: (a) mixing a liquid monomer with substantially insoluble particles in the liquid monomer, forming a mixture of monomeric particles; (b) supplying a continuous flow of liquid, from the mixture of monomer particles, to a vacuum environment, at a temperature both below the decomposition temperature and at the polymerization temperature of the monomeric particle mixture; (c) continuously atomizing the mixture of monomeric particles in the form of a continuous flow of small droplets. (d) continuously vaporizing the small droplets by the continuous contact of the small droplets on a hot surface having a temperature equal to or above a boiling point of the liquid monomer and the particles, but below a pyrolysis temperature, forming a composite vapor; and (e) continuously condensing the composite vapor cryogenically on a cold substrate, thereby forming the composite polymer layer. Although the liquid monomer may not be conjugated due to the curing steps, the use of conjugate particles may preserve conjugation within the polymeric material. If the flash evaporation is further combined with the plasma deposition, then both the conjugate particles and the monomer can be conjugated. Therefore, an object of the present invention is to provide a method for producing a composite polymer, through instantaneous evaporation. A further object of the present invention is to provide a method for producing a conjugated polymer through flash evaporation. An advantage of the present invention is that it allows to produce composite layers, through instantaneous evaporation. Another advantage of the present invention is that multiple layers of materials can be combined. For example, as described in U.S. Patent No. ,547,508, 5,395,644 and 5,260,095, incorporated herein by reference, multiple polymeric layers, alternating layers of polymer and metal, and other layers, can be produced with the present invention, under vacuum conditions. The subject of the present invention is particularly indicated and claimed, in a distinctive manner, in the conclusive portion of this specification. However, both the organization and the method of operation, together with advantages and additional objects thereof, can best be understood by reference to the following detailed description, in combination with the drawings, in which similar reference characters refer to to similar elements.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a cross-section of a combination of the prior art, of a light discharge plasma generator, with inorganic compounds, with flash evaporation. Figure 2 is a cross section of the apparatus of the present invention, of instantaneous evaporation and deposition of luminous discharge plasma, combined. Figure 2a is an end view of cross section of the apparatus of the present invention.

Figure 3 is a cross section of the present invention, wherein the substrate is the electrode.

DESCRIPTION OF THE PREFERRED MODALITY (S) (S) In accordance with the present invention, a solid, first composite polymer layer is produced by the steps of: (a) mixing a liquid monomer with substantially insoluble particles in the liquid monomer, forming a mixture of monomeric particles; (b) instantaneously evaporating the mixture of monomeric particles, forming a composite vapor; and (c) cryogenically condensing, continuously, the composite vapor, on a cold substrate, and crosslinking a monomeric cryogenically condensed layer, thereby forming the composite polymer layer. Instant evaporation comprises the steps of: (a) supplying a continuous flow of liquid from the mixture of monomer particles to a vacuum environment, at a temperature both below the decomposition temperature and at the polymerization temperature of the mixture of monomeric particles; (b) continuously atomizing the mixture of monomer particles in the form of a continuous flow of small droplets; (c) continuously vaporizing the small droplets by continuously contacting the droplets on a hot surface having a temperature equal to or above a boiling point of the liquid monomer and the particles, but below a pyrolysis temperature, forming a compound vapor. Insoluble is defined as not dissolving. Substantially insoluble refers to an amount of a material in the form of particles, not dissolved in the liquid monomer. Examples include solid particles that are insoluble or partially soluble in the liquid monomer, immiscible liquids that are totally or partially miscible / insoluble in the liquid monomer, and solids that can be dissolved and have a concentration greater than the solubility limit of the monomer , so that a quantity of the solid that can dissolve, remains undissolved. The liquid monomer can be any liquid monomer useful in flash evaporation, to produce polymeric films. The liquid monomer includes, but is not limited to, acrylic monomer, for example tripropylene glycol diacrylate, tetraethylene glycol diacrylate, tripropylene glycol monoacrylate, caprolactone acrylate and combinations thereof; methacrylic monomers and combinations thereof. The (meth) acrylic monomers are particularly useful in the production of altered molecular polymers (PMA), electroluminescent polymers (PEL), and electroluminescent electrochemical cells (CEL). The insoluble particle can be any type of insoluble or partially insoluble particle, having a boiling point below a hot surface temperature, in the process of instantaneous evaporation. For PEL / CEL devices, the preferred insoluble particles are organic compounds including, but not limited to, N, N'-Bis (3-ethylphenyl) -N, N '-diphenylbenzidine (TPD) - a transport material by holes for PEL and PMA, and Tris (8-quinolinolate) aluminum III (Alq3) - an electroluminescent and electron transport material, for the PEL and PMA. To obtain a CEL it is necessary to add an electrolyte, usually a salt, for example Bistrifluoromethylsulfonylimide, lithium trifluoromethanesulfonate (CF3SO3LÍ), and combinations thereof. The particle can be conjugated or unconjugated, and the monomer can be conjugated or unconjugated. The unconjugated particle or monomer includes, but is not limited to, phenylacetylene derivatives, for example Trans-Polyphenylacetylene, polyphenylenevinylene and combinations thereof, Trifenildiamine derivative, Quinacridone and combinations thereof. The insoluble particles are preferably of a volume much less than about 5,000 micrometers (with a diameter of about 21 micrometers) or equal to it, preferably less than or equal to about 4 micrometers (with a diameter of about 2 micrometers). In a preferred embodiment the insoluble particles are sufficiently small with respect to the density of the particles and the density and viscosity of the liquid monomer, such that the sedimentation rate of the particles within the liquid monomer is many times greater than the time necessary to transport a portion of the liquid monomer mixture, from a tank to the atomization nozzle. It should be noted that it may be necessary to stir the liquid monomer mixture of particles, in the tank, to maintain the suspension of the particles and to avoid settling. The mixture of monomer and insoluble or partially soluble particles can be considered a liquid paste, a suspension or an emulsion, and the particles can be solid or liquid. The mixture can be obtained through several methods. One method is to mix insoluble particles of a specified size, in the monomer. Insoluble particles of a solid of a specified size can be obtained by direct purchase or by manufacturing them through one of several standard techniques, including, but not limited to, grinding large particles, precipitation in a solution, melting / sprayed under controlled atmospheres, rapid thermal decomposition of precursors of a solution, as described in U.S. Patent No. 5,652,192 incorporated herein by reference. The steps of U.S. Patent No. 5,652,192 consist in making a solution of a soluble precursor, in a solvent, and flowing the solution through a reaction vessel, pressurizing and heating the flowing solution, and forming substantially insoluble particles, Then suddenly cool the hot flowing solution, and prevent the growth of the particles. Alternatively, larger sizes of the solid material can be mixed in the liquid monomer and then stirred, for example with ultrasound, to break the solid material into particles of a sufficiently small size. The liquid particles can be obtained by mixing a liquid immiscible with the monomeric liquid and stirring with ultrasound or mechanical agitation, to produce liquid particles in the liquid monomer. Immiscible liquids include, for example, fluorinated monomers.

In the spray, the small droplets can be only particles alone, particles surrounded by liquid monomer and liquid monomer alone. Since both the liquid monomer and the particles evaporate, it has no consequence whatsoever of the forms that are selected. However, it is important that the small drops are small enough to vaporize completely. Accordingly, in a preferred embodiment the size of the small droplets can vary from about 1 micrometer to about 50 micrometers.

Example 1 A first solid polymeric layer was produced, in accordance with the method of the present invention. Specifically, the mixture of acrylic monomer, 50.75 ml of tetraethylene glycol diacrylate plus 14.5 ml of tripropylene glycol monoacrylate plus 7.25 ml of caprolactone acrylate, plus 10.15 ml of acrylic acid, plus 10.15 ml of EZACURE (a benzophenone mixture photoinitiator commercialized by Sartomer Corporation of Exton Pennsylvania) was mixed with 36.25 grams of solid N, N'-Bis (3-methylphenyl) -N, N '-diphenylbenzidine particles having a wide range of particle sizes ranging from very fine to size of sand grains. The mixture was then stirred with a 20 kHz ultrasonic tissue grinding machine for about 1 hour to break up the solid particles and form a fine suspension. The initial mixture / suspension, having approximately 40 vol.% Or 72.5 g. Of particles, was found to clog the 0.129 cm (0.051 inch) spray nozzle such that the mixture was diluted to approximately 20 vol.%. 36.25 grams, to avoid clogging. It will be apparent to a person skilled in the liquid paste / suspension flow technique that increasing the size of the nozzle can handle higher concentrations. The mixture was heated to about 45 ° C and stirred to prevent settling in. The mixture was pumped through a 0.20 cm (0.08 inch) inner diameter and approximately 61 cm (24 inches) long capillary tube to the 0.129 cm (0.051 inch) spray nozzle that atomized (25 kHz ultrasonic atomizer) the mixture in the form of small droplets that fell onto a surface maintained at approximately 343.3 'C (650' F). Instant evaporation was maintained at approximately 287.8 * C (550 * F) to prevent cryogenic condensation of the monomer on the walls of the flash chamber.The vapor was cryogenically condensed on a polyester fabric (PET) maintained at a low temperature, with cooling water, introduced at a temperature of approximately 12.8 'C (55"F) followed by curing by UV radiation. The cured polymer was clear and deposited at speeds of approximately 4 microns in thickness at 4 meters / minute. However, speeds of hundreds of meters per minute can be achieved.

Example 2 A solid, polymeric first layer was produced according to the method of the present invention and with the parameters specified in Example 1, with the following exceptions. The solid particles consisted of the 19.5 grams (approximately 10.75% by volume) of Tris (8-quinolinolate) -aluminum III consisting of a few solid, coarse pieces, of more than 0.635 cm (0.25 inches) of transverse dimension. The capillary tube was 0.081 cm (0.032 inches) in internal diameter and approximately 60.96 cm (24 inches) in length to the spray nozzle. The cured polymer was produced at a speed of approximately 4 microns in thickness at 4 m / min.

Example 3 An experiment was carried out as in Examples 1 and 2, but using a combination of the mixtures of Example 1 and Example 2 together with 5 g of Bistrifluoro-methylsulfonylimide electrolytic salt. The cured polymer was transparent and was produced at a speed of approximately 4 microns in thickness at a rate of 1 m / min.

Alternative Modalities The method of the present invention can obtain a polymeric layer, either by radiation curing or self-curing. In radiation curing (Figure 1) the monomeric liquid may include a photoinitiator. An instantaneous evaporator 106 is used in an environment or vacuum chamber, to deposit a monomeric layer on a surface 102 of a substrate 104. In addition, an electron beam or ultraviolet light gun (not shown) is provided, downstream of the instantaneous evaporation unit, to crosslink or cure the monomeric cryogenically condensed layer. A light discharge plasma unit 100 can be used to burn the surface 102. The light discharge plasma unit 100 has a housing 108 surrounding an electrode 112 which can be smooth or which can have pointed projections 114. An inlet 110 allows the entry of a gas for engraving, for example oxygen or argon. In the autocurado, an instantaneous evaporator and a plasma generator of luminous discharge are used, combined, without the need to use the electron beam gun or the ultraviolet light. In Figure 2 an apparatus for self-curing is shown. The apparatus and method of the present invention are preferably within a low pressure (vacuum) environment or chamber. The pressures preferably range from about 10"1 torr (1.35 kg / m2) to 10" 6 torr (1.35x10"5 kg / m2) Instant evaporator 106 has a housing 116, with an inlet 118 for monomer and an atomizing nozzle 120. The flow passing through the nozzle 120 is atomized in the form of particles or small droplets 122 which collide on the heated surface 124 where the particles or small droplets 122 evaporate instantaneously to form a gas, evaporated product or composite vapor that it flows past a series of baffles 126 and up to an outlet 128 for composite vapor, and is cryogenically condensed on the surface 102. Cryogenic condensation on the baffles 126 and other internal surfaces is prevented by heating the deflectors 126 and Other surfaces, up to a temperature greater than a cryogenic condensation temperature or dew point, of the composite vapor, although other arrangements have been used. In the gas flow distribution, it has been found that the baffles 126 provide a suitable gas flow distribution or uniformity, while allowing easy scaling to large surfaces 102. The outlet 128 for the composite vapor directs the gas towards a light discharge electrode 204 creating a luminous discharge plasma from the composite vapor. In the embodiment shown in Figure 2, the light discharge electrode 204 is placed in a light discharge housing 200 having an inlet 202 for composite vapor, near the outlet 128 for composite vapor. In this embodiment, the housing for light discharge 200 and the light discharge electrode 204 are maintained at a temperature above a dew point of the composite vapor. The light discharge plasma leaves the housing for light discharge 200 and is cryogenically condensed on the surface 102 of the substrate 104. The monomeric light discharge plasma is cryogenically condensed on a substrate, where the crosslinking results from the radicals created in the plasma of luminous discharge and achieve self-healing. It is preferred that the substrate 104 be cooled. In this embodiment the substrate 104 moves and can be electrically non-conductive, conductive, or it can be polarized with an applied voltage. A preferred form of the light discharge electrode 200 is shown in Figure 2a. In this preferred embodiment, the light discharge electrode 204 has a shape such that the composite vapor flow coming from the inlet 202 for composite vapor flows substantially through an opening 206 of the electrode. Any form of electrode can be used, to create the light discharge, however, the preferred shape of the electrode 204 does not obscure the plasma of the composite vapor, and its symmetry, relative to the outlet slit 202 of the monomer and the substrate 204, provides uniformity of the plasma through the width of the substrate, while the movement of the substrate a uniformity across the width is obtained. The separation of the electrode 204 from the substrate 104 is a free space or distance that allows the plasma to strike the substrate. This distance that the plasma extends from the electrode will depend on the species of evaporated product, the geometry of the electrode 204 / substrate 104, the electrical voltage and frequency, and the pressure in the standard form as described in detail in ELECTRICAL DISCHARGES IN GASSES, FM Penning, Gordon and Breach Science Publishers, 1965, and which is summarized in THIN FILM PROCESSES, J.L. Vossen, W. Kern, editors, Academic Press, 1978, Part II, Chapter II-1, Glow Discharge Sputter Deposition, both incorporated herein by reference. Figure 3 shows an apparatus suitable for batch operation. In this embodiment, the light discharge electrode 204 is sufficiently close to a part 300 (substrate) to allow the plasma to strike the substrate 300. This distance that the plasma extends from the electrode will depend on the species of product evaporated, electrode geometry 204 / substrate 104, electrical voltage and frequency, and pressure in the standard form as described in ELECTRICAL DISCHARGES IN GASSES, FM Penning, Gordon and Breach Science Publishers, 1965, incorporated herein by reference. In this way, the part 300 is coated with the monomeric condensate and self-cured to produce a polymeric layer. Sufficiently close to, can refer to, rest on, in direct contact with, or separated by a free space or distance. This distance that the plasma extends from the electrode will depend on the species of evaporated product, the geometry of the electrode 204 / substrate 104, the electric voltage and frequency, and the pressure in the standard form as described in ELECTRICAL DISCHARGES IN GASSES, FM Penning, Gordon and Breach Science Publishers, 1965. In this embodiment it is preferred that the substrate 300 does not move or is stationary during cryogenic condensation. However, it may be advantageous to rotate the substrate 300 or move it laterally to control the thickness and uniformity of the monomeric layer cryogenically condensed thereon. Because the cryogenic condensation occurs rapidly, in a matter of seconds, the part can be removed after coating and before a coating temperature limit is exceeded. In operation, either as a method for the deposition of plasma-intensified chemical vapor, of high molecular weight monomeric materials, on a substrate, or as a method for producing self-curing polymeric layers (especially multiple polymeric layers (MCP)) , the composite polymer can be formed by the cryogenic condensation of the monomeric composite plasma, of light discharge, on a substrate, and by crosslinking the luminous discharge plasma thereon. The crosslinking results from the radicals created in the luminous discharge plasma, thus enabling self-curing. The liquid monomer can be any liquid monomer, useful in flash evaporation, to produce polymeric films. When the apparatus of Figure 2 is used to obtain self-curing, it is preferred that the material or monomeric liquid have a low vapor pressure, preferably less than about 10 torr (135.97 kg / m2) at 28.3 'C (83 * F). ), more preferably less than about 1 torr (13.59 kg / m2) at 28.3"C (83 * F), and most preferably less than about 10 millitorr (0.136 kg / m2) at 28.3" C (83) * F) For monomers from the same chemical family, monomers with low vapor pressures usually have higher molecular weights and can be cryogenically condensed, more easily, than monomers of lower molecular weight and with lower vapor pressures. The low vapor pressure monomers can be cryogenically condensed, more easily, than the low molecular weight monomers. By using instantaneous evaporation, the monomer vaporizes so rapidly that the reactions that generally occur from the heating of a liquid monomer, at an evaporation temperature, simply do not occur. In addition to the evaporated product from the liquid monomer, additional gases can be added through the inlet 130 and into the instantaneous evaporator 106, upstream of the outlet 128 for the evaporated product, preferably between the hot surface 124 and the first baffle 126. close to hot surface 124. The additional gases may be organic or inorganic for the purposes included, but not limited to, regulation, reaction, and combinations thereof. Regulation refers to providing enough molecules to maintain plasma illumination in circumstances of low evaporated product flow. Reaction refers to chemical reaction to form a compound different from the evaporated product. Regulatory gases include, but are not limited to, group VIII of the periodic table, hydrogen, oxygen, nitrogen, chlorine, bromine, polyatomic gases including, for example, carbon dioxide, carbon monoxide, water vapor, and combinations thereof. An exemplary reaction is that of adding oxygen gas to the monomer evaporated product, hexamethyldisiloxane, to obtain silicon dioxide. Although a preferred embodiment of the present invention has been presented and described, it will be apparent to those skilled in the art that many changes and modifications can be made without departing from the invention in its broader aspects. Therefore, it is intended that the appended claims cover all those changes and modifications that fall within the true spirit and scope of the invention.

Claims (17)

NOVELTY OF THE INVENTION Having described the above invention, it is considered as a novelty, and therefore, the content of the following is claimed as property: CLAIMS

1. A method for producing a solid, first polymeric layer characterized in that it comprises the steps of: (a) mixing a liquid monomer with substantially insoluble particles in the liquid monomer, forming a mixture of monomeric particles; (b) supplying a continuous flow of liquid, from the mixture of monomer particles, to a vacuum environment, at a temperature both below the decomposition temperature and at the polymerization temperature of the monomeric particle mixture; (c) continuously atomizing the mixture of monomeric particles, to form a continuous flow of small droplets; (d) continuously vaporize the small droplets by continuously contacting the small droplets on a hot surface having a temperature equal to or above the boiling point of the liquid monomer and the particles, but below a pyrolysis temperature, forming a composite vapor; and, (e) cryogenically condensing, continuously, the composite vapor, on a cold substrate, and crosslinking a monomeric cryogenically condensed layer, thereby forming the polymeric layer.

2. The method according to claim 1, characterized in that the liquid monomer is selected from the group consisting of (meth) acrylic monomers and combinations thereof.

The method according to claim 1, characterized in that the acrylic monomer is selected from the group consisting of tripropylene glycol diacrylate, tetraethylene glycol diacrylate, tripropylene glycol monoacrylate, caprolactone acrylate and combinations thereof.

4. The method according to claim 1, characterized in that the particles are selected from the group consisting of organic solids, liquids, and combinations thereof.

The method according to claim 4, characterized in that the organic solids are selected from the group consisting of N, N '-Bis (3-methylphenyl) -N, N' -diphenylbenzidine, Tris (8-quinolinolate) aluminum III , and combinations thereof.

6. The method according to claim 1, characterized in that the particles are selected from the group consisting of the phenylacetylene derivative, triphenyldiamine derivative, quinacridone and derivatives thereof.

The method according to claim 1, characterized in that the crosslinking is crosslinking by radiation.

8. The method according to claim 1, characterized in that it further comprises the step of passing the composite vapor past a light discharge electrode, before the cryogenic condensation, wherein the crosslinking is self-curing.

The method according to claim 1, characterized in that it further comprises adding an additional gas to the composite vapor, upstream of an outlet for compound vapor, of an instantaneous evaporator.

10. The method according to claim 9, characterized in that the additional gas is a regulating gas.

The method according to claim 9, characterized in that the additional gas is a reaction gas.

The method according to claim 11, characterized in that a reaction gas is oxygen gas and the compound vapor includes hexamethyldisiloxane.

A method for producing a solid, composite polymeric first layer, characterized in that it comprises the steps of: (a) mixing a liquid monomer with substantially insoluble particles in the liquid monomer, forming a mixture of monomeric particles; (b) instantaneously evaporating the mixture of monomer particles in a vacuum environment, forming a composite vapor; and, (c) cryogenically condensing, continuously, the composite vapor, on a cold substrate, and crosslinking a monomeric cryogenically condensed layer, thereby forming the polymeric layer.

The method according to claim 13, characterized in that the flash evaporation comprises the steps of: (a) supplying a continuous flow of liquid, from the mixture of monomer particles, to a vacuum environment, at a temperature below, both of the decomposition temperature and the polymerization temperature of the monomeric particle mixture; (b) continuously atomizing the mixture of monomeric particles, in the form of a continuous flow of small droplets; (c) continuously vaporize the small droplets by continuously contacting the small droplets on a hot surface having a temperature equal to or above a boiling point of the liquid monomer and the particles, but below a pyrolysis temperature, forming the composite vapor.

15. The method according to claim 13, characterized in that the crosslinking is crosslinking by radiation.

16. The method according to claim 13, further comprising the step of passing the composite vapor, past a light discharge electrode, before the cryogenic condensation, wherein the crosslinking is self-curing.

17. The method according to claim 13, characterized in that the particles are selected from the group consisting of phenylacetylene derivative, triphenyldiamine derivative, quinacridone and combinations thereof.