JPH023455A - Curing of organic coated article - Google Patents

Abstract

PURPOSE: To raise cure degree of the cover in comparison with the conventional method by heating the covered substrate with an organic covering composition which can be cured by specified radiation, using together with the condensilble inert pelfluoro compound vapor and radiant energy.

CONSTITUTION: The organic covering composition of free radical polymerization or cation polymerization which can be cured by radiation, is cured by the following processes of (A) and (B). That is (A) the process of covering the above composition on the base material, and (B) the process that the above cover is exposed to the condensible inert pelfluoro compound vapor as well as to radiant energy, thereby the cover is cured to the condition of solvent resistance. The above radiation curing organic covering composition contains one or more kind of organic monomer oligomer, or prepolymer which has one or more free radical polymerizable functional group and/or one or more cationic poymerizable functional group. The above curing method is suitable in particular to be used for abrasion resistance cover and weather-proof cover.

COPYRIGHT: (C)1990,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a method of curing organic coatings using steam heating. The invention also relates to cured coatings and curing equipment.

Several publications describe methods of curing resin coatings using steam heating. For example, R.D. Daniel S.
One ” vapor phase Solderi
ngwit 11374-682 (February 27 to March 1, 1979) suggests curing resin coatings using vapor phase soldering equipment. U.S. Patent No. 4,517
．． No. 556 (Lambert et al.) reports the use of steam heating to cure thermosetting conductive epoxide inks. Japanese Patent Application No. 60-23074 describes the use of steam heating to crosslink cable insulation.

Two papers by Mathias et al.
essRadiation CurabLe Con
ductive engineering
On for? initiating process
s/5) JC.

Atlanta, Josia, pp. 13-1 to 13-22 (
September 10, 1984) and “Radiatio
n: A Cure for PT1! (February 2013) uses steam heating at steam temperatures of 155°C and 215°C to cure a solvent-free conductive acrylate-based radiation-curable ink modified to be cured by heat alone. The method is described. Mathias et al. reported poor results using an inert perfluorinated compound liquid boiling at 101° C. and attributed the cause to insufficient heating rate. Also, Mathi as et al.
The use of other heating methods for curing inks is also described, and since these inks do not require time-consuming pre-drying, they can be used with either ultraviolet (VV) light, heat or a combination of both. He said it can be cured directly. However, Mathias et al. did not elaborate on which heating method should be used in such combinations, nor did they exemplify either the combination of steam heating and UV radiation.

There are several publications describing methods of curing compositions using a combination of radiant energy and heat from typical heat sources (eg, ozone). Such publications include U.S. Pat. No. 4,246,298 (Guarnery et al.);
No. 288,527 (Morgan).

No. 4,444j806 (Morgan et al.), and No. 4,548.895 (Eng.
″Radiation-Induced Catio
nic Polymerization-UV Cur
able EpOX7- Ba5ed Coating
s'for MetalFinishing Pro
cesses / 81JC, Paper PC-76
-506m deer, Illinois (September 28, 1976)
, and W. R. Watt, “UV Curi
ng of 1poxides byl 3, 4.7~
25 pages (November 1986). Guarn
The Ery et al. patent specification and the Watt article point out that the epoxy-paste systems they describe did not cure above about 120-130°C.

The present invention provides a method for curing a radiation-curable organic coating composition that is free-radically polymerizable or cationically polymerizable, comprising: (a) coating said composition onto a substrate; and then #:1) The coating is coated with a condensable inert perfluorinated compound vapor (C).
v) curing the coating to a solvent-resistant state by simultaneously exposing the coating to radiant energy while subjecting the coating to steam heating in the coating.

The use of steam heating and radiant energy according to the method of the invention provides several advantages. For example, 1) the coating can be rapidly heated to the temperature of the boiling perfluorinated liquid;

2) Excludes air (oxygen) from the coating surface, thereby reducing the risk of fire or explosion when curing coatings containing flammable solvents, and removing oxygen inhibition of free radically polymerizable coatings.

3) The degree of hardening is greater than that obtained using steam heating alone, radiant energy alone, and a combination of radiant energy and heating methods other than steam heating.

FIG. 1 is a sectional view of an apparatus for carrying out the method of the invention on a single article or a patch of articles.

FIG. 2 is a cross-sectional view of an apparatus for carrying out the method of the invention on a continuously moving belt conveying such articles.

FIG. 3 is a sectional view of an apparatus for carrying out the method of the invention on a continuously moving coated maple tree.

Radiation-curable organic coating compositions that are cured by the method of the present invention include one or more organic monomers having one or more free radically polymerizable functional groups and/or one or more cationically polymerizable functional groups; Contains 2% OjJ mer or prepolymer. The coating composition may optionally include one or more suitable photocatalysts and/or photoinitiators capable of curing the composition when exposed to radiant energy of a suitable wavelength and intensity. No photocatalyst or photoinitiator is required when using a radiant energy source with a sufficiently high radiant flux density (eg, electron beam radiation). The coating compositions can be used as paints, adhesives, masks, inks (e.g. so-called polymer thick films or "PTF J inks"), abrasion-resistant coatings, weather-resistant coatings (e.g. exterior signage coatings), insulation coatings, etc. The process according to the invention is particularly suitable for use with abrasion- and weather-resistant coatings, since the process according to the invention results in particularly durable coatings as a result of the increased degree of hardening. .

Particularly suitable free-radically polymerizable coating compositions exhibit a solvent-resistant state (
That is, it can be cured to the point where the coating does not come off when rubbed many times with absorbent cotton soaked in a solvent that dissolves uncured coatings, such as 2-butanone. Suitable compositions are widely known and commercially available. These include ethoxyethoxyethyl acrylate, phenoxyethyl acrylate and methacrylate, inbornyl acrylate, tetrahydrofurfuryl acrylate and methacrylate, and inoctyl acrylate. Other free radically polymerizable monomers include ethylenically unsaturated compounds such as N.

N-dimethylacrylamide, N-isobutylacrylamide, diacetone acrylamide, N-methoxymethylacrylamide, N-butoxymethylacrylamide and methacrylamide, styrene, dichlorostyrene, divinylbenzene, vinyltoluene, N-vinylpyrrolidone, N-vinylpiperidone, N - Vinylcaprolactam and N-vinylcarbazole. Free radically polymerizable prepolymers useful in this 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, reactions of polyols with incyanatoethyl acrylate or methacrylate. product,
Included are reaction products of polyisocyanates and hydroxyalkyl acrylates or methacrylates, and reaction products of carboxylic anhydrides and hydroxyalkyl acrylates or methacrylates. If desired, monomers, oligomers or prepolymers can also be used, for example to modify the properties of the coating.

Free-radically polymerizable monomers, oligomers or prepolymers can also be combined with ethylenically unsaturated compounds that do not themselves homopolymerize under free-radical polymerization conditions. Such compounds include non-terminally unsaturated polyesters (e.g. diols and unsaturated dicarboxylic acids such as itaconic acid,
(polyesters derived from maleic acid or fumaric acid), allylamides, allyl esters, allyl ethers and vinyl ethers. Typical compounds include triallyl isocyanurate, diallyl phthalate, diallyl adipate, diallyl maleate, sialyl itaconate, triallyl citrate, trimethylolpropane diallyl ether, trimethylolpropane triallyl ether, pentaerythritol triallyl ether, and isobutyl vinyl ether. , octadecyl vinyl ether, hexanediol divinyl ether, triethylene glycol divinyl ether, bisphenol A
di-2-vinyloxyethyl ether, trimethylolpropane trivinyl ether, and mixtures thereof.

Particularly suitable cationically polymerizable coating compositions can be cured to a solvent-resistant state in the presence of a suitable catalyst for cationic polymerization, such as Pronsted acids, their precursors, or Lewis acid complexes. Suitable compositions are widely known and commercially available. These include monomers such as the above-mentioned sita vinyl ether, oxirane group-containing (epoxy-containing) monomers,
Oligomers and prepolymers, such as those described in U.S. Pat.
No. 117.099 (Proops et al.), No. 4.329.
478 (Bohr) and 4.394,403 (8mlth), and Lee and Nθville.

Handbook of gpoxy Re5ins
, McGraw-Hllll Book COo, New York (1967) and Bruins.

Epoxy Re5in Technology,
John Vileer and Bonsa, New York (1968).

Cationically polymerizable compounds can also be combined with copolymerizable organic compounds that do not themselves homopolymerize under cationic polymerization conditions. Hydroxyl compounds, such as those described in US Pat. No. 4,318,766 (Smlth), are particularly suitable copolymerizable compounds.

The coating composition can include a bi-reactive monomer, oligomer or prepolymer having at least one free-radically polymerizable moiety and at least one cationically polymerizable moiety attached thereto. Representative di-reactive 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 typical dually reactive prepolymer can be prepared by reacting one mole of bisphenol A diglycidyl ether or one mole of but/diol diglycidyl ether with one mole of acrylic acid. Other representative dually reactive monomers, oryhimers or prepolymers include 3-(methacryloxy)probyltrimethoxine, glycizol acrylate, the reaction product of glycidol and incyanatoethyl methacrylate, Included are reaction products of 2 moles of bisphenol A diglycidyl ether and 1 mole of itaconic acid.

Photocatalysts or photoinitiators for use in coating compositions according to the present invention are well known and widely available. Typical free radical photocatalysts or photoinitiators useful for free radically polymerizable compositions include heptano- or diketones such as benzophenone and force/7-arquinone, benzoin derivatives such as benzoin ethyl ether, pencil derivatives thereof, For example, the dimethyl ketal, a-substituted acetophenones such as jetoxyacetophenone, and a-
Hydroxy-α, α-dimethylacetophenone, and halomethyl-s-triazines, such as 2,4-bis(
trichloromethyl)-6-p-methoxystyryl-s-
Includes triage.

These photocatalysts or photoinitiators may be used alone or in combination with a thermally activated initiator. Typical thermally activated initiators include diacyl peroxides such as benzoyl peroxide, sialkyl peroxides such as zokpolberoxide, hydroperoxides such as t-butyl hydroperoxide, peroxy esters such as t-
-butyl perbenzoate, and pinacols, such as benzopinacol.

Typical cationic photocatalysts or photoinitiators include complex halodenide "onium" salts, such as U.S. Pat.
phenyldiazonium hexafluorophosphate containing an alkoxy or benzyloxy group as a substituent on the phenyl group as described in Jacobs No. 00.115 (Jacobs) and US Pat. No. 3.981.897 (Cr1
vello), No. 4.058.401 (Cr1ve
llo), No. 4.101.513 (EPox etc.)
, No. 4.169,478 (Cr1vello),
No. 4,173.476 (5m1tb, etc.), and No. 4
, 394.403 (Smlth).

Representative onium salts are diphenyliodonicum hexafluorophosphate, triphenylsulfonium hexafluoroantimonate, and diphenyl-4-thiothenoxyphenylsulfonicum hexafluoroantimonate. If necessary, optical sensitization to long wavelength light can be carried out as described in US Pat. No. 4.026.705 (Cr1ve
llo et al.) and No. 4.069.054 (Sm1th
) can be carried out as described in the specification. The amount of photocatalyst or photoinitiator in the coating composition can be varied over a wide range because experience has shown that these photocatalysts or photoinitiators are essentially inert unless they perform a photoactivating action. Because I understood. A particularly suitable amount of photocatalyst or photoinitiator is from about 0.02% to about 1% based on the total weight of the coating composition.
0% by weight, more preferably from about 0.1% to about 5% by weight.

The coating composition is prepared using conventional inert solvents such as toluene, 2-
It can include butanone, propyl acetate, etc., and can also include common reactive solvents such as butyl acrylate, butyl glycidyl ether, etc. The composition may also contain the usual auxiliary agents, such as dyes, pigments, indicators, matting agents, lubricating and 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, antimonooxide, lithopone or titanium dioxide), or electrically conductive Fillers (eg, silver, gold or copper) may also be included.

Examples of substrates to which the coating composition can be applied include rigid or flexible materials, such as metals with or without primers (e.g. steel, copper, aluminum or tin sheets), sheets and films of plastics ( (e.g. polyester, polycarbonate, epoxy, polypropylene or polyvinyl chloride), composites (e.g.
epoxy-glass or epoxy-graphite laminates), glass, ceramic laminates, fibrous substrates (e.g. non-woven materials or woven fabrics made from natural or synthetic fibers or mixtures thereof), and laminates of the above materials. It will be done. Coated articles that can be made by coating such base materials include circuit boards and various connecting materials, printing plates, container bodies,
and lids, vehicle bodies and parts, metal coil articles (eg, building site tenders), floor tiles, and the like.

Coating a substrate with a coating composition can be accomplished by conventional methods, but the method used will depend on the nature of the coating composition, the nature of the substrate to be coated, and the desired properties and shape or contour of the final coated article. Depends on factors. Suitable coating methods include brush coating, dip coating, spraying, knife coating, par coating, gravure coating, curtain coating, and the like. The thickness of the coating will vary depending on the factors listed above, but will range from about 2.5 to 250 microns (0.1 to 10 mils) within the shell.

The coating composition may be steam heated in one substantially closed apparatus for admitting the heating steam and recirculating the steam heating liquid. Apparatus for curing is created by modifying the vapor phase soldering apparatus to include a radiant energy source. For example, U.S. Patent No. 3,866.30
No. 7 (Pfahl et al.) describes an apparatus suitable for steam heating coated articles, patches of articles, or continuously moving belts carrying such articles. For use in the present invention, the device of Pfahl et al. may be used with the addition of a suitable radiant energy source within the device or with an energy source external to the device so that substrates within the device can be irradiated with radiant energy. It can be fixed. Other vapor phase heating devices that can be modified for use with the present invention include Dani
elson article and the patent specification of I+ambert et al. (both cited above).

Referring now to the drawings, FIG. 1 shows a suitable 4IK apparatus for use in curing coatings on a single article or batch of articles using CrV and C-PV. The apparatus comprises a chamber or volume 1 having a heating coil 2 or other means for heating and boiling a liquid 4 of inert perfluorinated compound.

A cooling coil 3 for condensing the hot perfluorinated compound vapor 6 is placed in the upper part of the vessel 1.

The coating 8 on the substrate 1 is cured by exposure to steam 6 and radiant energy from an energy source 9. The used fluid can be recovered and purified by conventional procedures such as filtration and distillation. It is desirable to provide exhaust means for exhausting by-products of decomposition products and low-boiling monomers from the fluid or coating composition from the curing apparatus.

FIG. 2 shows a particularly suitable apparatus for use in curing coatings on articles placed on a continuously moving belt.

The lower part of the vessel 10 contains a reservoir 5 filled with an inert perfluorinated compound liquid 4 heated by a heater 2 . Cooling coils 13 and 14 for condensing the hot perfluorinated compound vapor 6 are placed at the inlet 11 and outlet 12 in the upper part of the vessel 10. The coating 8 on the substrate 7 is conveyed through the container 10 on a constantly moving belt 15. Coating 8 is cured by radiant energy from energy source 9 and steam 6 passing through window 16 (eg quartz).

FIG. 3 shows a particularly suitable apparatus for curing coatings on continuously moving maple wood. The lower part of the vessel 11 contains a heater 2 for boiling a liquid 4 of inert perfluorinated compound. Cooling coils 18 and 19 are placed at the inlet 20 and outlet 21 of the vessel 11 for condensing the hot perfluorinated compound vapor 6. The maple 22, which is constantly moving while supporting the covering 23, is moved by rollers 24 and 25 that pass through the container 11.
and moving across 26. The coating 23 absorbs radiant energy and steam 6 from the energy source 9 passing through the window 16.
It is hardened by

Particularly suitable inert perfluoro compound liquids used to heat the coating composition to create a condensable vapor for thermally polymerizing include perfluoroalkanes, such as perfluorooctane, perfluorotrialkylamines, such as Berber. Included are fluorotrizotylamine, and perfluorodialkyl ethers, such as perfluorodiptyl ether. Many useful liquids are commercially available, such as F'LUO for electronics, available from 3M.
R Engineering Nl! iRT'' liquid, LX, duPont de
“F50N” available from Nemoursa+co.
K”Liquid, Engineering SC Chemicals Lim1te
and GALDEN H8" liquid, available from Montediaon, Inc., Inc.

A list of particularly suitable inert perfluorinated compound liquids and their boiling points is provided below. The boiling point data is R, D, D
anielgon, ” F'1uoro Ethe
RS and John Wiley & 8ona New York, 1980).

Perfluoro-4-methylmorpholine perfluorotriethylamine perfluoro-2-ethyltetrahydrofuran perfluorohexane 58
Perfluoro-4-isozorobylmorpholine
95 Perfluorosotethyl ether
102 Perfluorooctane
1o3 Perfluorotrizolo♂amine 130 Perfluorononane 123 Perfluorotrizotylamine 1
78 Perfluorosohexyl ether
181 Perfluorotetrahydro-7enanthrene 215 The choice of a particular inert perfluorinated compound liquid or liquid mixture is typically governed by the particular coating composition to be cured and by the nature of the substrate, and is generally determined by experimentation. It will be done.

Naturally, liquid availability and price are also important factors.

Exposure of the coating composition to radiant energy occurs during steam heating;
Alternatively, it can be carried out either before or after heating. Preferably, the coating is exposed to radiant energy during steam heating.

The radiant energy source may be visible light, ultraviolet light, electron beam radiation, or a combination thereof. UV light can be obtained from solar lamps, high pressure or medium pressure mercury lamps, xenon lamps,
It can be provided by a mercury-xenon lamp, Radhe-1 or other known light source. These lamps may be of the long-arc type or the short-arc type, and may be of the water-cooled type or the air-cooled type. The lamps may include a envelope capable of transmitting light at a wavelength of about 185 nm to 400 nm. The envelope may be made of quartz, e.g. [5 pectrocil J, or glass, e.g.
7J Arc and Hanovia 78.74 Watts/cI
Includes IL arc lamps. If these lamps are placed in a steam heating device, they should be positioned so that they can be uniformly and completely irradiated with the coating composition. A particularly useful arrangement is to place the radiant energy source on top of the steam heating device and irradiate the substrate to be irradiated in a downward direction.

Curing times for steam heating and radiant energy exposure will vary depending on the coating composition, the thickness of the coating, the temperature of the heating steam, and the intensity or flux of the radiant energy. However, by using the method of the present invention, very fast coating cure rates can be obtained for selected coating compositions, such as short cure times of less than 60 seconds, and even less than 15 seconds.

The invention will be explained in more detail by the following examples, which should not be considered as a limitation on the scope of the invention. Unless otherwise specified, all parts and percentages are by weight.

Example 1 This example illustrates the simultaneous use of steam heating and UV to cure cyacrylate resins.

“Epocryl 370 J Bisphenol A diglycidyl ether diacrylate (5hell Chem
75% solid solution of ical Co, ) in toluene 20
0 parts were mixed with 15 parts of a 2O4 solid solution of C1ba-Geigy 651 J photoinitiator (C1ba-Geigy Co, ) in toluene.
Apply to the sodium chloride plate with a 10 wire wound rod,
l) 6V) (V) Air-dried for at least 15 minutes. 12-70rI on this coating
The coating was exposed to ultraviolet light from a 275 watt solar lamp located at L. Photopolymerization and optional thermal polymerization of the coatings were carried out under five different conditions.

6. Mix perfluorooctane/perfluoro-2-butyltetrahydrofuran in container 1 shown in FIG.
The coating was immersed under a four-way liquid layer. The container is made of insulated stainless steel and has an inner diameter of 20 cm and a depth of 23 cWL. The liquid was at room temperature (approximately 24°C).

The coatings were placed on a flat surface and exposed to UV while surrounded by room temperature room air.

The coatings were placed in a container surrounded by room temperature room air and exposed to UV light.

The coating was placed in a container and heated in air to 55-60°C for a 10 minute rest period and then exposed to UV. The air inside the container was heated using a hot plate.

The coating was placed in a container and heated to 57°C in a saturated vapor bath of perfluorohexane for a 1 minute rest period, then exposed to UV light.
exposed to. Approximately 8 cm of steam covered the sample. A 5-height cooling coil at the top of the container prevented vapors from escaping from the container. UV immersion in perfluorinated vapor
Continued during exposure.

The progress of curing of each coating is recorded at 1405. It was decided to monitor the disappearance of the cm-1 acrylate group infrared absorption band. The results are shown in Table ■.

a. Due to the UV lamp, the ambient temperature reached 59°C.

It had a dull appearance.

The above data shows that the combination of U'V and steam heating (condition v), the combination of UV and room temperature fluorocarbon liquid (condition J), the combination of UV and room temperature air (conditions l and If),
Alternatively, it is explained that either UV or heated air (condition 1v) results in faster or more complete curing.

Comparative Example 1 This comparative example illustrates the use of steam heating alone for thermal free radical curing of diacrylate resins.

A coated sodium chloride plate is made as in Example 1, but with Irg
In place of the Acure 651 photoinitiator solution, 15 parts of a 20% solid solution of deoxidized benzoyl in 2-butanone was used. Thermal polymerization of the coating was carried out under four different conditions using the apparatus under condition 011) of Example 1. The four heating conditions used in this comparative example were as follows: (1) 130 forced air at °C, (jl) 82 °C saturated vapor of perfluorohebutane,
(Ill) 102°C saturated steam of 8 combined perfluorooctane/perfluoro-2-butyltetrahydrofuran, or h) 1 of mixed perfluoro-N,N-diptyl-N-methylamine/perfluoro-N-butylgiberidine.
60℃ saturated steam.

The results are shown in Table H.

Table ■ 0.5 4 30
61 The above data shows that when only steam heating is used, the UV
It has been shown that substantially higher temperatures or longer heating times are generally required to obtain a degree of cure comparable to that obtained by the combination of heat and steam heating.

Example 2 A coating is prepared as described in Example 1, except that the concentration of photoinitiator is reduced to a quarter of that used in Example 1. Example 10 Using the method, thermal and photopolymerization of the coating was carried out simultaneously under three conditions: (1) ambient air at 100-105°C; (1) 57% of perfluorohexane; °C saturated steam, or (lit) 102 °C saturated steam of mixed perfluorooctane/perfluoro-2-butyltetrahydrofuran.

The results are shown in Table ■.

Table [rV exposure time (min) Conditions (1) UV curing in air at 100-105°C, 08. 17 ・33. 67 ■ Conditions (1) UV curing conditions in steam at 57°C ω1) UV curing a in steam at 102°C, 2-detanone treatment after irradiation for 1.25 minutes (Table ■, same as footnotes) 1 line There was a 20% weight loss only along the edges of the coating, but the gloss was retained.

b. When using the hand mold described in a, a weight loss of less than 10 cm was observed only along the edge of the coating, and the gloss of the coating was retained and the shape was round.

The above data show that the method of the present invention can provide a substantial degree of cure even after very short processing times.

Example 6 In this example, a blend of an ethylenically unsaturated cellulose ester derivative and an ethylenically unsaturated ester is optionally thermally polymerized simultaneously with steam heating, or after thermal polymerization is performed first, followed by UV curing. state. The coating formulation consists of a 1:1 equivalent adduct of incyanatoethyl methacrylate and hydroxyl groups of cellulose acetate zolobionate (
r504-0.2 J, Eastman Chemi
35% solid solution of cal Co, ) in propyl acetate 8
0 parts, 1=1 equivalent adduct (rnmR- 33
2J, Day Chemia'l Co, )'s 75
20 parts of a solid solution of
e 184 J photoinitiator (C1ba-Geigy Co
, ) was prepared by mixing 8.6 parts of a 20% solid solution of . The resulting mixture was applied to a sodium chloride plate using a #16 wire-wound rod and air-dried for at least 15 minutes before irradiation.

27 placed 12-7 cIft above the covering.
The coating was photopolymerized by exposure to ultraviolet light from a 5 watt solar lamp. The method of photopolymerization and optional simultaneous thermal polymerization of this coating or thermal polymerization before photopolymerization is carried out in 3 ways.
Performed under ambient conditions: (1) surrounded by room air at room temperature; (1) mixed perfluorooctane/perfluoro-
Simultaneous photopolymerization is carried out by immersing in saturated steam of 2-butyltetrahydrofuran at 102°C, or photopolymerization is carried out in the C process pv atmosphere described in II) (1), however, prior to photopolymerization, immersion in saturated steam for 1 minute is carried out. The coating was allowed to reach the C-PV temperature by soaking for a rest period.

Cure progress was measured by monitoring the disappearance of the 1630 cm-1 methacrylate group infrared absorption band.

The results are shown in Table ■.

Table ■ Methacrylate reaction percentage UV curing conditions in steam at 102°C (1) Curing conditions (lil). 08. 25. 50 4a 0b 67゜a,, when rubbed with absorbent cotton thoroughly soaked in 2-butanone,
Dissolution of the coating surface occurred, leaving 9 surfaces with a dull finish.

b. When rubbed in the same manner as in a, only a slight surface blemish appeared.

c, When rubbed in the same manner as in a, there was no effect on the coating.

Example 4 Three coating compositions were made to allow comparisons to be made between free radically polymerizable and cationically polymerizable compositions. Coating 4-1 was the same coating composition used in Example 3.

Coating 4-2 was prepared using cellulose acetate (-r5) in a 3:1 mixture of n-propyl acetate and ethanol.
04-0.2J, Eastman Chemical
89 parts of a 20% solid solution of Co, ), cycloaliphatic diepoxide (znL-4221J,
e Co, ) ii parts, and 5.8 parts of a 20% solid solution of triarylsulfonium hexafluoroantimonate photoinitiator in 2-butanone.

The preparation of this photoinitiator is further described in US Pat. No. 4,173,476 (5ml et al.). The resulting mixture contained epoxide and hydroxyl groups in a 3=20 molar ratio. Coating 4-3 contains the same three solid components used in coating 4-2, each at 92', 4:7.6:
A weight ratio of 5.2 was included, thus giving a 1:1 molar ratio of epoxide to hydroxyl groups. Using a wire-wound rod, separate each coating by 5
cIIL x 7.6 cm x 1 thickness was applied to the lath board.

For coating 4-1, use a #16 rod, and for coating 4-1.
A #32 bar was used for 2 and 4-3, resulting in approximately the same dry film thickness. The coatings were air-dried for 15 minutes before irradiation.

The coatings were photopolymerized by exposure to ultraviolet light from a 275 watt solar lamp placed 12-7 cIL above the coatings. Photopolymerization and optional thermal polymerization of the coatings were carried out under four conditions: (1) surrounded by room air at room temperature, (11) simultaneous photopolymerization while immersed in 82° C. saturated vapor of perfluorohebutane; ) mixed perfluorooctane/perfluoro-2-
Simultaneous photopolymerization by immersion in 102 °C saturated steam of butyltetrahydrofuran, or IV) mixed perfluoro-
N,N-dibutyl-N-methylamine/perfluoro-
Simultaneously photopolymerized by immersion in N-butylpiperidine saturated steam at 130°C. After UV exposure, each coating was cooled to room temperature using forced air.

The progress of curing was monitored by measuring the weight loss of each film as a function of irradiation time after 100 back and forth rubbings with absorbent cotton soaked in 2-butanone. The reference condition for curing was arbitrarily chosen as the tTV exposure time resulting in an observed or interpolated coating weight loss of 10 ts. The results are shown in Table V.

4-2 >1500 75 168
4-3 >>1500 120 24
13 The above data show that the use of high steam heating temperatures reduces the time to reach a state of solvent resistance, even for cationically polymerizable epoxide-crosslinked polyol compositions.

Example 5 This example illustrates the use of the present invention to cure a coating composition containing two different polymerizable groups. One was subjected to oxygen suppression during curing. Bisphenol A diglycidyl ether (rEpon 828J, 5hall Che
mical Co, ) was reacted with acrylic acid in an equivalent ratio of 0.5 moles of acrylic acid per mole of epoxide groups. 85% solution of the resulting reaction product in toluene 200
1 part was mixed with 17 parts of a 20 part solution of triarylsulfonicum hexafluoroa/timonate photoinitiator in 2-butanone.

These coatings were applied as in Example 1 to sodium chloride boards. The coating was then photopolymerized in air at room temperature (using the method of Example 1) and optionally the mixed Berthoud was further thermally polymerized in 102°C saturated steam of octane/perfluoro-2-butyltetrahydrofuran. . The progress of curing is 915
This was determined by monitoring the disappearance of the infrared absorption band of the epoxide at cm-1 and the acrylate group at 1405 cfIL-1. The solvent resistance was evaluated and the flood polymerization conditions and results are shown in Table ■. Experiments 1a to 1 in the table
c indicates that the first sample was continuously observed. Experiments 2a to 2b s 3a to 3a and 5a to 5b in the table also represent continuous observation of the second, third, and fourth samples, respectively.

Table■ Room temperature air 102℃ 102℃ steam 0.5a b C15 0,5 0,5 0,5 0,5 a. Adhesiveness. Non-stick but solvent soluble.

C0 Solvent Swellability d, Solvent Resistance The above data demonstrate not only the reduction in the required total polymerization time achieved by using steam heating and aV simultaneously, but also the inhibition that can be achieved when curing certain reactive groups. It also explains the degree of

Example 6 This example illustrates the effect of varying photoinitiators and polymerization conditions. Three coating formulations were made, formulations rCJ, rRJ.
, or "CRJ." Formulation C was identical to that of Example 5. Formulation R was similar to Formulation C, except that the photoinitiator was replaced with an equal weight of "Rgacure 651 J Photoinitiator ( C1ba - Geigy Co, ). Formulation CR was made from a 1:1 mixture of Formulation C and Formulation R.

Coatings were prepared and evaluated using the method of Example 5.

The results are shown in Table ■.

Example 7 This example describes the application of a coating composition similar to the compositions described in Examples 5 and 6 as a structural adhesive.

A solvent-free 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 semi-acrylated zoepoxide used in Example 5 and 40 parts of glycidyl methacrylate. The resulting fluid composition was coated onto a 5cRX 7.6cm x 1 am thick glass plate using a #3232 part rod and UV-treated in room air for 3 minutes using a 275 Watt sun lamp placed 12-7an above the plate. exposed to. The resulting coating was sticky and dissolved in 2-butanone. A second 2.5 cm x 7.6 box x 1 B thick glass plate was crimped against this coating and the resulting assembly was heated for 10 minutes in 102°C vapor of mixed perfluorooctane/perfluoro-2-butyltetrahydrofuran. A strong firm laminate resulted. The cured coating that was not sandwiched between the glass plates was coated with a cotton applicator thoroughly soaked in 2-butanone for 100 strokes.
After rubbing it several times, there was only a slight scratch.

If you replace UV exposure in air for 3 minutes with immediate 1 minute rV exposure in saturated steam at 102°C,
2-Butanone treatment resulted in a clear, glossy, vertical, tack-free coating that was completely unaffected.

Example 8 This example illustrates how to cure various coating compositions using the present invention. Low viscosity solvent-free coating compositions of type B are prepared by dissolving 2 parts of photoinitiator in a mixture of 60 parts of prepolymer ("base resin") and 40 parts of low viscosity organic compound ("diluent monomer"). did. The ingredients are as follows: Base resin I Bisphenol A diglycysol ether diacrylic v-) ("Epocryl 370 J, 8
hell Chemical Co.).

Base resin: 0 acrylic acid per 11 moles of epoxide
．． Bisphenol A diglycidyl ether (“1ltpon828”) reacted with acrylic acid in an equivalent ratio of 5 molar
J, shell Chemical Co, ).

Base resin ■ Bisphenol A diglycidyl ether (“DBR337”, Dow Chemical Co.
).

Diluent monomer A Butyl acrylate diluent monomer B Glycidyl methacrylate diluent monomer C Butyl glycidyl ether photoinitiator 1
gaaure 651°" Photoinitiator 2 Triarylsulfonium hexafluoroantimonate coating #1616 part rod 5cIILX7.6cmX1
It was applied on a glass plate of mg thickness. Above the covering 12.
The coating was photopolymerized by exposing it to ultraviolet light from a 275 Watt solar lamp placed on the No. 7 steel. This photopolymerization can be carried out in room air or mixed perfluorooctane/perfluoro-2
-Butyltetrahydrofuran vapor at 102°C. All cured coatings were smooth. C engineering P
Curing times measured for coatings cured at K
It was considered that the time needed to become The cure time for coatings cured in air at room temperature was taken as the time for the coating to reach only the non-stick state. The ingredients, polymerization mechanism and results in each coating composition are shown on the clothing.

Table ■ >>600 >>600 >>600 a, R = free radical polymerizable; C = cationic polymerizable; CR = can be polymerized by both cationic and free radical mechanisms.

The above data demonstrate that the combination of UV and steam heating significantly accelerates the cure rate of all coatings, as does UV t-in air.

Example 9 This example illustrates the improvement in weatherability of coatings cured by the method of the invention. 100 parts of the hexafunctional acrylic ester described in Example 1 of U.S. Pat. No. 4,249.011 (Wendling), "Irgacure 651J
4 parts of photoinitiator and 233 parts of 2-butanone as solvent
A coating composition was prepared from the parts. This composition was applied to a clear polycarbonate plastic sheet using a 1#14 wire wound rod and allowed to air dry. 300 watts/inch 4H mercury lamp (%del?440, F'usion 8ystema
) The coatings were cured using a continuous format vapor phase soldering apparatus (Shichiderue L-6, HTC) equipped with an ultraviolet source containing UV light. This 07 source was isolated from the soldering equipment by a quartz plate.

Perfluoro-N,N-diptyl- boiling at 130°C
A mixture of N-methylamine and VerfluoCl-N-decylbiperidine was used for steam heating.

The steam heating fluid was heated to 130° C. and the UV lanzo was turned on. 1.511 coated plastic sheet in curing equipment
It passed at a partial speed. A comparison sample was cured in the same equipment under the same conditions, except that the atmosphere inside the equipment was 40°C.
air was used. The measured thickness of the cured coating is 8.4
It was a micron.

The progress of curing was determined by monitoring the disappearance of the 810 cm-" C=C absorption band. The adhesion of the coating to the plastic substrate was evaluated. A piece of “Elcotah”
Abrasion resistance was evaluated during and before and after a 400 hour accelerated weathering cycle by pressing the transparent tape of the J Open Collar 610 firmly and measuring the percentage of coating remaining in the area when it was removed. did. This is described in U.S. Pat. No. 4,073,967 (Eland MiG
The test was carried out by measuring the pressure required to create scratches on the coated surface after 10 back and forth rubbings with a 000 grade steel coolant using the test method described in ). This accelerated weathering cycle consisted of Q, [1rVCyc
1i cσ1traviolet Weatheri
It was carried out using ng Te5tar. This procedure consists of 6.5 hours of UV exposure at 65°C for each cycle followed by <
A 1.5 hour water vapor exposure at 50°C is used. Display the results■
Shown below.

In C1pv UV softening 40℃ in the air σV hardening 2.11 0.70 1.40 0#36 0.36 a, 92% acrylate reaction.

b. Acrylate reaction 81q6゜The above results demonstrate that the coating composition cured by the method of the present invention has a high degree of hardening (acrylate reaction q6), improved initial abrasion resistance (residual coating q), and improved abrasion resistance after weathering. Explain.

The following names used herein are the trademarks "FLUOR NICRT J", "PRICON I"
J, “IPIJσTIC(!ppJ,”GAIIDI
CN Hs J, ``5 psctrocil J, ``Py
rex J, rH3T7J, “IPOaryl 570
J, "engineering rgacure651", r 1: rgac
ure 184 J, [DIR-332J, "DIR-
337J, rIRL-4221J, “MPON 82
8 J, and “5cotch J.

It will be apparent to those skilled in the art that various modifications and changes to this invention can be made without departing from the scope and spirit of this invention. The invention is not intended to be limited to the specific examples described herein.

[Brief explanation of the drawing]

1 is a cross-sectional view of an apparatus for applying the method of the invention to a single article or a patch of articles, and FIG. FIG. 3 is a sectional view of an apparatus for applying the method of the invention to a continuously moving coated maple; FIG. 1.10.17... Container, 4... Perfluoro compound liquid, 9... Energy source, 2... Heater 7... Base material, 3゜3゜4゜8゜9... Cooling coil.

Claims (9)

[Claims] (1) A method of curing a free radical polymerizable or cationic polymerizable radiation curable organic coating composition, comprising: (a) coating the composition onto a substrate; (b) then applying the coating to the substrate; The above method comprising the steps of simultaneously exposing the coating to a condensable inert perfluorinated compound vapor and exposing the coating to radiant energy thereby curing the coating to a solvent resistant condition. 2. The method of claim 1, wherein the coating composition is free radical polymerizable. (3) A method according to any one of claims 1 and 2, wherein the coating composition comprises an acrylate or methacrylate resin. (4) The method of claim 1, wherein the coating composition is cationically polymerizable. (5) The method according to claim 1 or 4, wherein the coating composition comprises an epoxy resin. 6. The method of claim 1, wherein the coating composition comprises a monomer, oligomer or polymer that is dually reactive, free radically polymerizable and cationically polymerizable. (7) The method according to any one of claims 1 to 6, wherein the perfluoro compound boils at a temperature of 50°C to 150°C. (8) A coating composition cured by the method according to any one of claims 1 to 7. (9) An apparatus used for curing a coating composition on a substrate, wherein the apparatus cures the coating composition by the method set forth in any one of claims 1 to 7. It comprises a chamber having a lower part and an upper part, the lower part having a reservoir containing a liquid of an inert perfluorinated compound and means for heating and boiling the liquid, and the upper part having a heat source. a cooling coil for condensing perfluorinated compound vapor and substantially preventing said vapor from escaping said chamber, and said apparatus includes radiation capable of irradiating said coating composition while heating said coating in said vapor. The above device having an energy source.