EP0323061B1 - Verfahren zum Aushärten von organischen Beschichtungen durch Anwendung von Kondensationswärme und Strahlungsenergie - Google Patents

Verfahren zum Aushärten von organischen Beschichtungen durch Anwendung von Kondensationswärme und Strahlungsenergie Download PDF

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EP0323061B1
EP0323061B1 EP88311679A EP88311679A EP0323061B1 EP 0323061 B1 EP0323061 B1 EP 0323061B1 EP 88311679 A EP88311679 A EP 88311679A EP 88311679 A EP88311679 A EP 88311679A EP 0323061 B1 EP0323061 B1 EP 0323061B1
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Prior art keywords
coating
radiant energy
cure
coatings
vapors
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French (fr)
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EP0323061A2 (de
EP0323061A3 (en
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Edward J. C/O Minnesota Mining & Deviny
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3M Co
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Minnesota Mining and Manufacturing Co
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D3/00—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials
    • B05D3/02—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials by baking
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F26—DRYING
    • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
    • F26B21/00—Arrangements or duct systems, e.g. in combination with pallet boxes, for supplying and controlling air or gases for drying solid materials or objects
    • F26B21/14—Arrangements or duct systems, e.g. in combination with pallet boxes, for supplying and controlling air or gases for drying solid materials or objects using gases or vapours other than air or steam, e.g. inert gases
    • F26B21/145—Condensing the vapour onto the surface of the materials to be dried
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D3/00—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials
    • B05D3/04—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials by exposure to gases
    • B05D3/0466—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials by exposure to gases the gas being a non-reacting gas
    • B05D3/0473—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials by exposure to gases the gas being a non-reacting gas for heating, e.g. vapour heating
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D3/00—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials
    • B05D3/06—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials by exposure to radiation
    • B05D3/061—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials by exposure to radiation using U.V.
    • B05D3/065—After-treatment
    • B05D3/066—After-treatment involving also the use of a gas
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F26—DRYING
    • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
    • F26B3/00—Drying solid materials or objects by processes involving the application of heat
    • F26B3/28—Drying solid materials or objects by processes involving the application of heat by radiation, e.g. from the sun
    • F26B3/283—Drying solid materials or objects by processes involving the application of heat by radiation, e.g. from the sun in combination with convection

Definitions

  • This invention relates to a method for curing an organic coating using condensation heating. This invention also relates to cured coatings and to a curing apparatus.
  • FR-A-2382278 discloses a method of curing a free-radically-polymerizable composition by exposing the composition to a radiation source in the presence of water vapor.
  • a method for curing a cationically-polymerizable, radiation-curable organic coating composition comprising the steps of
  • condensation heating and radiant energy provides several advantages, including:
  • the radiation-curable organic coating compositions that are cured by the methods embodied in the invention contain one or more organic monomers, oligomers or prepolymers having one or more free-radically-polymerizable functional groups and/or one or more cationically-polymerizable functional groups.
  • the coating compositions can optionally contain one or more appropriate photocatalysts and/or photoinitiators capable of curing the composition upon exposure to radiant energy of a suitable wavelength and intensity.
  • a photocatalyst or photoinitiator is not required when a radiant energy source of sufficiently high flux density (e.g., electron beam radiation) is employed.
  • the coating compositions can be used as paints, adhesives, masks, inks (e.g., the so-called polymer thick film or "PTF" inks), abrasion-resistant coatings, weather-resistant coatings (e.g., coatings for outdoor signs), and insulative coatings.
  • inks e.g., the so-called polymer thick film or "PTF" inks
  • abrasion-resistant coatings e.g., the so-called polymer thick film or "PTF" inks
  • weather-resistant coatings e.g., coatings for outdoor signs
  • insulative coatings e.g., insulative coatings.
  • the methods embodied in the invention are especially preferred for use with abrasion-resistant and weather-resistant coatings, since the enhanced degree of cure provided by the invention yields an especially durable coating.
  • Preferred free-radically-polymerizable coating compositions are capable of being cured to a solvent-resistant state (i.e., a state in which the coating is not removed by multiple rubs of a swab saturated with a solvent for the uncured coating, e.g., 2-butanone) upon exposure to a suitable source of free radicals, e.g., a peroxide catalyst.
  • suitable compositions are widely known and commercially available, and include monomers such as ethoxyethoxyethyl acrylate, phenoxyethyl acrylate and methacrylate, isobornyl acrylate, tetrahydrofurfuryl acrylate and methacrylate, and isooctyl acrylate.
  • free-radical-polymerizable monomers include ethylenically unsaturated compounds such as N,N-dimethylacrylamide, N-isobutylacrylamide, diacetoneacrylamide, N-methoxymethylacrylamide, N-butoxymethylacrylamide and methacrylamide, styrene, dichlorostyrene, divinylbenzene, vinyl toluene, N-vinyl-pyrrolidone, N-vinylpiperidone, N-vinylcaprolactam and N-vinylcarbazole.
  • ethylenically unsaturated compounds such as N,N-dimethylacrylamide, N-isobutylacrylamide, diacetoneacrylamide, N-methoxymethylacrylamide, N-butoxymethylacrylamide and methacrylamide, styrene, dichlorostyrene, divinylbenzene, vinyl toluene, N-vinyl-pyrrolidone, N-vinylpiperidone
  • Free-radically-polymerizable prepolymers useful in the invention include acrylate and methacrylate esters of polyols (e.g., esters of aliphatic polyols, polyether polyols, polyester polyols, and polyurethane polyols), reaction products of polyfunctional epoxides with acrylic or methacrylic acid, reaction products of polyols with isocyanatoethyl acrylate or methacrylate, reaction products of polyisocyanates with hydroxyalkyl acrylates or methacrylates, and reaction products of polycarboxylic anhydrides with hydroxyalkyl acrylates or methacrylates.
  • Mixtures of monomers, oligomers or prepolymers can also be used if desired, e.g., to modify the properties of the coating.
  • the free-radically-polymerizable monomers, oligomers or prepolymers can also be combined with ethylenically unsaturated compounds that by themselves do not homopolymerize under free radical polymerization conditions.
  • ethylenically unsaturated compounds include non-terminally-unsaturated polyesters (e.g., polyesters derived from diols and unsaturated dicarboxylic acids, such as itaconic, maleic, or fumaric acids), allyl amides, allyl esters, allyl ethers, and vinyl ethers.
  • Representative compounds include triallylisocyanurate, diallylphthalate, diallyladipate, diallylmaleate, diallylitaconate, triallylcitrate, trimethylolpropane diallyl ether, trimethylolpropane triallyl ether, pentaerythritol triallyl ether, isobutyl vinyl ether, octadecyl vinyl ether, hexanediol divinyl ether, triethyleneglycol divinyl ether, di-2-vinyloxyethyl ether of Bisphenol A, trimethylolpropane trivinyl ether, and mixtures thereof.
  • Preferred cationically-polymerizable coating compositions are capable of being cured to a solvent-resistant state when in the presence of a suitable catalyst for cationic polymerization, e.g., Bronsted acids, their precursors, or Lewis acid complexes.
  • a suitable catalyst for cationic polymerization e.g., Bronsted acids, their precursors, or Lewis acid complexes.
  • Suitable compositions are widely known and commercially available, and include monomers such as the vinyl ethers described above, and oxirane-group containing (epoxy-containing) monomers, oligomers and prepolymers such as those described in U.S. Pat. Nos.
  • the cationically-polymerizable compounds can also be combined with copolymerizable organic compounds that by themselves do not homopolymerize under cationic polymerization conditions.
  • Hydroxyl compounds are preferred copolymerizable compounds, such as those described in U.S. Pat. No. 4,318,766 (Smith).
  • the coating composition can contain bireactive monomers, oligomers or prepolymers having attached thereto at least one free-radically-polymerizable moiety and at least one cationically-polymerizable moiety.
  • bireactive monomers, oligomers or prepolymers include the partially acrylated or methacrylated polyfunctional epoxides described in U.S. Pat. No. 4,428,807 (Lee et al.).
  • a representative bireactive prepolymer can be made by reacting one mole of Bisphenol A diglycidyl ether or one mole of butanediol diglycidyl ether with one mole of acrylic acid.
  • bireactive monomers, oligomers or prepolymers include 3-(methacryloxy)propyl trimethoxysilane, glycidyl acrylate, the reaction product of glycidol with isocyanatoethyl methacrylate, the reaction product of two moles of Bisphenol A diglycidylether with one mole of itaconic acid, and the like.
  • Photocatalysts or photoinitiators for use in the coating compositions of the invention are well known and widely available.
  • Representative free radical photocatalysts or photoinitiators useful with free-radically-polymerizable compositions include mono- or diketones such as benzophenone and camphorquinone, benzoin derivatives such as its benzoin ethyl ether, benzil derivatives such as its dimethylketal, ⁇ -substituted acetophenones such as diethoxy acetophenone and ⁇ -hydroxy- ⁇ , ⁇ -dimethylacetophenone, and halomethyl-s-triazines such as 2,4-bis(trichloromethyl)-6-p-methoxystyryl-s-triazine.
  • photocatalysts or photoinitiators can be used alone or in combination with heat-activated initiators.
  • Representative heat-activated initiators include diacyl peroxides such as benzoyl peroxide, dialkyl peroxides such as dicumyl peroxide, hydroperoxides such as t-butyl hydroperoxide, peroxyesters such as t-butyl perbenzoate, and pinacols such as benzopinacol.
  • Representative cationic photocatalysts or photoinitiators include "onium" salts of complex halogenides, e.g., the phenyldiazonium hexafluorophosphates containing alkoxy or benzyloxy radicals as substituents on a phenyl radical described in U.S. Pat. No. 4,000,115 (Jacobs), and the diaryliodonium and triarylsulfonium metal complex salts described in U.S. Pat. Nos.
  • onium salts of complex halogenides e.g., the phenyldiazonium hexafluorophosphates containing alkoxy or benzyloxy radicals as substituents on a phenyl radical described in U.S. Pat. No. 4,000,115 (Jacobs)
  • diaryliodonium and triarylsulfonium metal complex salts described in U.S. Pat. Nos.
  • Illustrative onium salts are diphenyliodonium hexafluorophosphate, triphenylsulfonium hexafluoroantimonate, and diphenyl-4-thiophenoxyphenylsulfonium hexafluoroantimonate. If desired, optical sensitization to longer wave lengths of light may be performed as described in U.S. Pat. Nos.
  • the amount of photocatalyst or photoinitiator in the coating composition can vary over a wide range, since the photocatalyst or photoinitiator is substantially inert unless photoactivated.
  • a preferred amount of photocatalyst or photoinitiator is 0.02% to 10% by weight based on the total weight of the coating composition, more preferably 0.1% to 5% by weight.
  • the coating compositions can contain conventional non-reactive solvents such as toluene, 2-butanone, propyl acetate, and the like, and can also contain conventional reactive solvents such as butyl acrylate, and butyl glycidyl ether.
  • compositions can also contain conventional adjuvants such as dyes, pigments, indicators, flatting agents, lubricants, dispersing aids, surfactants, extenders, viscosity modifiers, non-electrically conductive fillers (e.g., calcium carbonate, quartz, diatomaceous silica, synthetic silica, talc, mica, bentonite, glass fibers, white lead, antimony oxide, lithopone or titanium dioxide), or electrically conductive fillers (e.g., silver, gold or copper).
  • conventional adjuvants such as dyes, pigments, indicators, flatting agents, lubricants, dispersing aids, surfactants, extenders, viscosity modifiers, non-electrically conductive fillers (e.g., calcium carbonate, quartz, diatomaceous silica, synthetic silica, talc, mica, bentonite, glass fibers, white lead, antimony oxide, lithopone or titanium dioxide), or electrically conductive fillers (e.g., silver, gold
  • Substrates on which the coating composition can be applied include rigid or flexible materials such as primed or unprimed metals (e.g. steel, copper, aluminum or tinplate), plastic sheets and films (e.g., polyester, polycarbonate, epoxy, polypropylene or polyvinylchloride), composites (e.g., epoxy-glass or epoxy-graphite laminates), glass, ceramics, fibrous substrates (e.g., nonwoven materials or woven fabrics formed from natural or synthetic fibers or mixtures thereof) and laminates of the foregoing materials.
  • Coated articles that can be made by coating such substrates include circuit boards and connectors, printing plates, container bodies and closures, vehicle bodies and component parts, metal coil goods (e.g. building siding), and floor tile.
  • the coating of substrates with the coating composition can be carried out by conventional methods, depending on factors such as the nature of the coating composition, the nature of the substrate to be coated, and the desired properties and shape or configuration of the final coated article. Suitable coating methods include brushing, dipping, spraying, knife coating, bar coating, gravure coating, curtain coating and the like. Coating thickness will vary depending on the above-described factors, but will generally be in the range of 2.5 to 250 um (microns) (0.1-10 mils).
  • the coating composition is preferably condensation heated within a substantially closed apparatus in order to contain the condensation heating vapor, and permit recycling of the condensation heating liquid.
  • the apparatus for curing can be made by modifying vapor phase soldering equipment to include a radiant energy source.
  • vapor phase soldering equipment for example, U.S. Pat. No. 3,866,307 (Pfahl et al.) describes equipment suitable for condensation heating a coated article, a batch of articles or a continuously moving belt bearing such articles.
  • the Pfahl et al. equipment can be modified for use in this invention by adding a suitable radiant energy source inside the equipment, or by placing the source outside the equipment in a manner that will allow the radiant energy to irradiate a substrate within the equipment.
  • Other vapor phase heating equipment that can be modified for use in this invention is shown in the Danielson paper and in the Lambert et al. patent, both of which are cited above.
  • FIG. 1 shows a preferred apparatus for use in curing coatings on a single article or a batch of articles using UV and CIPV.
  • the apparatus contains a chamber or vessel 1 having a heating coil 2 or other means for heating and boiling the inert perfluorochemical liquid 4. Cooling coils 3 for condensing the hot perfluorochemical vapors 6 are located in the upper portion of the vessel 1.
  • Coating 8 on substrate 7 is cured by exposure to the vapors 6 and radiant energy from energy source 9. Used fluids can be recovered and purified by conventional procedures, e.g., filtration and distillation. Exhaust means for the curing apparatus are recommended to exhaust any by-product decomposition products or low boiling monomers from the fluid or coating composition.
  • FIG. 2 shows a preferred apparatus for use in curing coatings on articles placed on a continuously moving belt.
  • Vessel 10 has a lower portion containing a reservoir 5 filled with inert perfluorochemical liquid 4 and heated by heater 2.
  • Cooling coils 13 and 14 for condensing the hot perfluorochemical vapors 6 are located in the inlet 11 and outlet 12 of the upper portion of vessel 10.
  • Coating 8 on substrate 7 is carried through vessel 10 on continuously moving belt 15. Coating 8 is cured by vapors 6 and radiant energy from energy sources 9 passing through windows 16 (made, for example, from quartz).
  • FIG. 3 shows a preferred apparatus for curing a coating on a continuously moving web.
  • the lower portion of vessel 17 contains heater 2 for boiling inert perfluorochemical liquid 4.
  • Cooling coils 18 and 19 for condensing the hot perfluorochemical vapors 6 are located in the inlet 20 and outlet 21 of the vessel 17.
  • Continuously moving web 22 bearing coating 23 moves over rollers 24, 25 and 26 through vessel 17.
  • Coating 23 is cured by vapors 6 and radiant energy from energy sources 9 passing through windows 16.
  • the preferred inert perfluorochemical liquids used to produce condensing vapors for heating and thermally polymerizing the coating composition include perfluoroalkanes such as perfluorooctane, perfluorotrialkylamines such as perfluorotributylamine, and perfluorodialkylethers such as perfluorodibutyl ether.
  • perfluoroalkanes such as perfluorooctane
  • perfluorotrialkylamines such as perfluorotributylamine
  • perfluorodialkylethers such as perfluorodibutyl ether.
  • Many useful liquids are commercially available and include "FLUORINERT” electronic liquids from 3M, "FREON E” liquids from E.I. duPont de Nemours & Co., "FLUTEC PP" liquids from ISC Chemicals Limited, and "GALDEN HS” liquids from Montedison, Inc.
  • inert perfluorochemical liquid or mixture of liquids will typically be governed by the particular coating composition to be cured and by the nature of the substrate, and will generally be determined empirically. Of course, availability and cost of the liquids are also important factors.
  • Exposure of the coating composition to radiant energy can be carried out before firing and after condensation heating. Preferably, the coating is exposed to radiant energy during condensation heating.
  • the radiant energy source can be visible light, UV light, electron beam radiation, or a combination thereof.
  • UV light is the preferred radiant energy source.
  • UV light can be supplied by sun lamps, high or medium pressure mercury lamps, xenon lamps, mercury xenon lamps, lasers, and other well known sources.
  • Lamps may be long arc or short arc, and can be water- or air-cooled.
  • the lamps can include envelopes capable of transmitting light of a wavelength of from about 185 nm to 400 nm.
  • the lamp envelope can be made of quartz, such as "Spectrocil" or of glass, such as "Pyrex".
  • Typical commercially available UV lamps include medium pressure mercury arcs such as the GE "H3T7" arc and the Hanovia 78.74 watt/cm arc lamp.
  • the lamps if positioned within the condensation heating apparatus, preferably are arranged so as to irradiate the coating composition evenly and completely.
  • the radiant energy source is placed at the top of the condensation heating apparatus and directed downward upon the substrate to be irradiated.
  • Cure times for condensation heating and radiant energy exposure will vary depending on the coating composition, coating thickness, the temperature of the condensation heating vapor and the radiant energy intensity or flux. However, very fast coating cure times, e.g., less than 60 seconds and as short as 15 seconds or less can be obtained for selected coating compositions using the method of this invention.
  • This example illustrates the simultaneous use of condensation heating and UV to cure a diacrylate resin.
  • 200 Parts of a 75% solids solution of "Epocryl 370" bisphenol A diglycidylether diacrylate (Shell Chemical Co.) in toluene was mixed with 15 parts of a 20% solids solution of "Irgacure 651" photoinitiator (Ciba-Geigy Co.) in toluene.
  • Coatings of the resulting mixture were applied with a #10 wire wound rod to sodium chloride plates and allowed to air dry for at least 15 minutes.
  • the coatings were exposed to UV light from a 275 watt sunlamp placed 12.7 cm above the coatings. Photopolymerization and optional thermal polymerization of the coatings were conducted under five different conditions:
  • This comparison example illustrates the use of condensation heating alone in the thermal free radical curing of a diacrylate resin.
  • Coated sodium chloride plates were prepared as in EXAMPLE 1, but using 15 parts of a 20% solids solution of benzoyl peroxide in 2-butanone in place of the Irgacure 651 photoinitiator solution.
  • Thermal polymerization of the coatings was conducted under four different conditions, using the apparatus of EXAMPLE 1, condition (3).
  • the four heating conditions used in this comparison example were:
  • Coatings were prepared as described in EXAMPLE 1 except that the concentration of photoinitiator was reduced to one fourth the concentration employed in EXAMPLE 1. Using the method of EXAMPLE 1, simultaneous thermal polymerization and photopolymerization of the coatings was conducted under the following three conditions:
  • This example describes the UV curing of a blend of an ethylenically-unsaturated cellulose ester derivative and an ethylenically unsaturated ester with optional simultaneous or prior thermal polymerization by condensation heating.
  • a coating formulation was prepared by mixing 80 parts of a 35% solids solution of a 1:1 equivalent adduct of isocyanatoethyl methacrylate and the hydroxyl groups of cellulose acetate propionate ("504-0.2", Eastman Chemical Co.) in propyl acetate, 20 parts of a 75% solids solution of a 1:1 equivalent adduct of isocyanatoethyl methacrylate and the hydroxyl groups of the acrylic acid esterification product formed from a 1:2 molar ratio reaction of itaconic acid with bisphenol A diglycidylether ("DER-332", Dow Chemical Co.), and 8.6 parts of a 20% solids solution of "Irgacure 184" photoinitiator (Ciba-Geigy
  • the coatings were photopolymerized by exposure to UV light from a 275 watt sunlamp placed 12.7 cm above the coatings. Photopolymerization and optional simultaneous or prior thermal polymerization of the coatings was conducted under three conditions:
  • Coating 4-1 was the same coating formulation used in Example 3.
  • Coating 4-2 was prepared by mixing 89 parts of a 20% solids solution of cellulose acetate propionate ("504-0.2", Eastman Chemical Co.) in 3:1 n-propyl acetate:ethanol, 11 parts cycloaliphatic diepoxide ("ERL-4221", Union Carbide Co.), and 5.8 parts of a 20% solids solution of triarylsulfonium hexafluoroantimonate photoinitiator in 2-butanone. Preparation of the photoinitiator is further described in U.S. Pat.
  • Coating 4-3 contained the same three solid ingredients employed in Coating 4-2 but in a weight ratio of 92.4:7.6:5.2, respectively, so that the molar ratio of epoxide to hydroxyl groups was 1:1.
  • Each coating was applied to a 5 cm x 7.6 cm x 1 mm thick glass plate using a wire wound rod. A #16 rod was used for coating 4-1 and a #32 rod was used for coatings 4-2 and 4-3 so that the dry film thicknesses were approximately equivalent. The coatings were allowed to air dry for 15 minutes prior to irradiation.
  • the coatings were photopolymerized by exposure to UV light from a 275 watt sunlamp placed 12.7 cm above the coatings. Photopolymerization and optional thermal polymerization of the coatings was conducted under four conditions:
  • This example illustrates the use of the invention to cure a coating composition containing two different polymerizable groups, one of which is subject to oxygen inhibition during cure.
  • Bisphenol A diglycidylether (“Epon 828", Shell Chemical Co.) was reacted with acrylic acid, at an equivalent ratio of 0.5 moles acrylic acid per mole of epoxide groups.
  • 200 parts of an 85% solution of the resulting reaction product in toluene were mixed with 17 parts of a 20% solution of triarylsulfonium hexafluoroantimonate photoinitiator in 2-butanone.
  • the coatings were applied to sodium chloride plates as in EXAMPLE 1.
  • the coatings were then photopolymerized in ambient air (using the method of EXAMPLE 1) and optionally further thermally polymerized in the 102°C saturated vapor of mixed perfluorooctane/perfluoro-2-butyltetrahydrofuran. Cure progress was determined by monitoring disappearance of the 915cm ⁇ 1 epoxide and 1405cm ⁇ 1 acrylate group infrared absorption bands. Solvent resistance was evaluated by wiping the coatings with up to 20 rubs of a 2-butanone-saturated cotton swab. The polymerization conditions and the results are set out below in Table VI.
  • Runs 1a - 1c in the table represent successive observations made on a first sample. Runs 2a-2b, 3a-3c, and 4a-4b in the table likewise represent successive observations made on second, third, and fourth samples, respectively.
  • the above data illustrates not only the reduction in required total polymerization time attained by using simultaneous condensation heating arid UV, but also the degree of control that can be attained when curing specific reactive groups.
  • Formulation C was identical to that of EXAMPLE 5.
  • Formulation R was like formulation C except that the photoinitiator was replaced with an equal weight of "Irgacure 651" photoinitiator (Ciba-Geigy Co.).
  • Formulation CR was made from a 1:1 blend of formulation C and formulation R.
  • This example illustrates a structural adhesive application for coating compositions like those described in EXAMPLE 5 and EXAMPLE 6.
  • a solventless coating composition was prepared by dissolving 3 parts of the triarylsulfonium hexafluoroantimonate photoinitiator used in EXAMPLE 5 in a mixture of 160 parts of the half-acrylated diepoxide used in EXAMPLE 5 and 40 parts glycidyl methacrylate.
  • the resulting fluid composition was coated onto a 5 cm x 7.6 cm x 1 mm thick glass plate using a #32 wire wound rod and exposed to UV for 3 minutes in room air using a 275 watt sunlamp placed 12.7 cm above the plate.
  • the resulting coating was tacky and soluble in 2-butanone.
  • Diluent monomer A Butyl acrylate.
  • Diluent monomer B Glycidyl methacrylate.
  • Diluent monomer C Butyl glycidyl ether.
  • Photoinitiator 1 "Irgacure 651”.
  • Photoinitiator 2 Triarylsulfonium hexafluoroantimonate.
  • the coatings were applied with a #16 wire wound rod onto, 5 cm x 7.6 cm x 1 mm thick glass plates.
  • the coatings were photopolymerized by exposure to UV light from a 275 watt sunlamp placed 12.7 cm above the coatings, with photopolymerization being carried out in room air or in the 102°C vapor of mixed perfluorooctane/perfluoro-2-butyltetrahydrofuran.
  • the cured coatings were all smooth.
  • the measured cure time for coatings cured in CIPV was taken as the time required for the coating to reach a tack-free state and exhibit resistance to 20 double rubs with a 2-butanone-saturated cotton swab.
  • a coating composition was prepared from 100 parts of the hexafunctional acrylic ester described in Example 1 of U. S. Pat. No. 4,249,011 (Wendling), 4 parts "Irgacure 651" photoinitiator, and 233 parts 2-butanone as solvent.
  • This composition was applied to clear polycarbonate plastic sheets with a #14 wire wound rod and allowed to air dry.
  • the coating was cured using a continuous in-line vapor phase soldering unit (Model IL-6, HTC) equipped with UV source containing a 118 watt/cm (300 watt/inch) 4H mercury lamp (Model F440, Fusion Systems).
  • the UV source was separated from the soldering unit by a quartz plate.
  • a mixture of perfluoro-N,N-dibutyl-N-methylamine and perfluoro-N-butylpiperidine boiling at 130°C was used for condensation heating.
  • the condensation heating fluid was heated to 130°C and the UV lamp was switched on.
  • the coated plastic sheets were passed through the curing apparatus at a speed of 1.5 m/min.
  • a comparative sample was cured in the same apparatus under the same conditions except that 40°C air was used as the atmosphere in the apparatus.
  • the measured thickness of the cured coatings was 8.4 ⁇ m (microns).
  • the coatings were evaluated for adhesion to the plastic substrate by measuring the percentage of the coating remaining in a razor cut crosshatched area following removal of a piece of "Scotch" Brand 610 transparent tape pressed firmly on the crosshatched area.
  • Abrasion resistance was evaluated before, during and after a 400 hour accelerated weathering cycle, by measuring the pressure required to scratch the coating surface after 10 double rubs with grade 000 steel wool, using the test described in U. S. Pat. No. 4,073,967 (Sandvig).
  • the accelerated weathering cycle was carried out in a QUV Cyclic Ultraviolet Weathering Tester set on Cycle 4-3, using the procedure described in ASTM Standard G53-77.

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Claims (7)

  1. Verfahren zum Härten einer radikalkettenpolymerisierbaren und durch Strahlung härtbaren organischen Beschichtungsmasse, welche Beschichtungsmasse in inerter perfluorchemischer Flüssigkeit unlöslich oder nicht dispergierbar ist, umfassend die Schritte:
    (a) Auftragen der Masse auf ein Substrat und sodann
    (b) Exponieren der Beschichtung an kondensierenden, inerten perfluorchemischen Dämpfen, welche Dämpfe durch Erhitzen und Kochen der inerten perfluorchemischen Flüssigkeit erzeugt werden, und gleichzeitiges Exponieren der Beschichtung an Strahlungsenergie, wodurch die Beschichtung zu einem lösemittelfesten Zustand gehärtet wird.
  2. Verfahren nach Anspruch 1, bei welchem die Beschichtungsmasse ein Acrylat- oder Methacrylatharz umfaßt.
  3. Verfahren nach einem der Ansprüche 1 oder 2, bei welchem die perfluorchemische Substanz zwischen 50 °C und 150 °C siedet.
  4. Verfahren nach einem der Ansprüche 1 bis 3, bei welchem die organische Beschichtung bi-reaktionsfähiges Monomer, Oligomer oder Polymer umfaßt.
  5. Verfahren nach einem der Ansprüche 1 bis 4, bei welchem die Strahlungsenergie UV-Strahlung umfaßt.
  6. Verfahren zum Härten einer kationisch polymerisierbaren, durch Strahlung härtbaren organischen Beschichtungsmasse, wobei die Masse in einer inerten perfluorchemischen Flüssigkeit unlöslich oder nicht dispergierbar, umfassend die Schritte:
    (a) Auftragen der Masse auf ein Substrat und sodann
    (b) Exponieren der Beschichtung an kondensierenden, inerten perfluorchemischen Dämpfen, welche Dämpfe eine Temperatur zwischen 130 °C und 150 °C haben und durch Erhitzen und Kochen der inerten perfluorchemischen Flüssigkeit erzeugt werden, und Exponieren der Beschichtung an Strahlungsenergie, wodurch die Beschichtung zu einem lösemittelfesten Zustand gehärtet wird und wobei die Exponierung an den Dämpfen und an der Strahlungsenergie entweder gleichzeitig oder die Exponierung an der Strahlungsenergie vor oder nach der Exponierung an den Dämpfen erfolgen kann.
  7. Verfahren nach Anspruch 6, bei welchem die Beschichtungsmasse ein Epoxidharz ist.
EP88311679A 1987-12-31 1988-12-09 Verfahren zum Aushärten von organischen Beschichtungen durch Anwendung von Kondensationswärme und Strahlungsenergie Expired - Lifetime EP0323061B1 (de)

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US14002487A 1987-12-31 1987-12-31
US140024 1987-12-31

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EP0323061A2 EP0323061A2 (de) 1989-07-05
EP0323061A3 EP0323061A3 (en) 1989-09-06
EP0323061B1 true EP0323061B1 (de) 1993-07-14

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EP88311679A Expired - Lifetime EP0323061B1 (de) 1987-12-31 1988-12-09 Verfahren zum Aushärten von organischen Beschichtungen durch Anwendung von Kondensationswärme und Strahlungsenergie

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EP (1) EP0323061B1 (de)
JP (1) JPH023455A (de)
KR (1) KR890009478A (de)
DE (1) DE3882351T2 (de)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4133290A1 (de) * 1991-10-08 1993-04-15 Herberts Gmbh Verfahren zur herstellung von mehrschichtlackierungen unter verwendung von radikalisch und/oder kationisch polymerisierbaren klarlacken
KR100441770B1 (ko) * 1998-12-24 2004-11-03 주식회사 유니지퍼 지퍼제조장치및제조방법
GB2349590A (en) * 1999-05-05 2000-11-08 Rexam Custom Ltd Adhesive coated conductive foil
DE102006041753B4 (de) * 2006-09-04 2010-04-15 Wolf Verwaltungs Gmbh & Co. Kg Trocknungskabine

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2808931A1 (de) * 1977-03-04 1978-09-07 Dynachem Corp Verfahren zum beschichten oder bedrucken eines substrates
FR2534260B1 (fr) * 1982-10-08 1986-01-10 Lambert Francois Procede de polymerisation de resines thermodurcissables

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EP0323061A2 (de) 1989-07-05
DE3882351T2 (de) 1994-01-05
EP0323061A3 (en) 1989-09-06
KR890009478A (ko) 1989-08-02
JPH023455A (ja) 1990-01-09
DE3882351D1 (de) 1993-08-19

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