Photonic lacquer coating of electrical wires

Abstract

The present invention relates to a wire coating composition comprising an infrared-sensitive compound that causes the conversion of absorbed light energy into heat and a matrix comprising a varnish that chemically or physically reacts upon heat treatment, a method for producing enameled wire, and uses thereof.

Description

[Technical Field]

[0001]

[0001] The present invention relates to a lacquer for insulated electric wires and a method for applying the lacquer thereto. [Background technology]

[0002]

[0002] Enameled wires may be wound in a coil shape inside electrical devices and have the function of mutually converting electrical energy and mechanical energy through a magnetic energy conversion process. Such enameled wires generally consist of a conductor such as a round wire or a flat wire made of copper or aluminum, and an insulating coating layer around the conductor. The coating layer is hardened on the wire by heat. The main function of the resulting coating is electrical insulation. The insulating material is usually made of a strong polymer film material rather than glassy enamel, as its name suggests.

[0003]

[0003] The coating varies depending on the application of the wire. Some wires are in the micrometer range and can be very small. On the other hand, in heavy electric motors, the diameter of round or rectangular wires can be up to several millimeters.

[0004]

[0004] The insulation of the electric wire can be applied in various modes depending on its shape and diameter. Horizontal or vertical application, or application using a die or felt are typical methods of applying insulation to electric wires.

[0005]

[0005] Enameled wires are widely used in various electrical installations and basically consist of a metal wire and an insulating coating layer around it. Such enameled wires are used in a variety of industrial fields, including heavy electrical equipment, automotive parts, home appliances, medical equipment, and core materials in the aerospace industry.

[0006]

[0006] The currently used coating consists of polyurethane, polyester, polyester imide, polyamide imide or polyvinyl formal. Usually, the coating layer is brought about by repeatedly applying it to the surface of the wire. The coating composition can be applied by spraying, by roller, by die, or by felt.

[0007]

[0007] Enamel wires have conventionally been prepared by coating a wire with one or more coating layers of a fluid resin material and drying and curing the resin material. To dry and cure the layer, the coated wire is fed into a furnace consisting of a heating chamber (arranged horizontally or vertically), where it is moved to a high-temperature zone (400 - 700 °C) where the solvent evaporates and then the film is cured. Thereafter, the wire can return into the coating circuit to add a layer of the coating. In this continuous process, up to 30 applications of the enamel can be applied until the desired layer thickness is obtained.

[0008]

[0008] WO2006088272A1 discloses an enamel varnish composition for enamel wires. The varnish composition contains a polyamide imide resin component contained in an organic solvent.

[0009]

[0009] US2010310787A1 relates to the use of tungsten oxide or tungstate to increase the amount of heat input of near-infrared rays in various processes, for example, laser welding of plastics, NIR curing of coatings, drying of printing inks, fixing of toner on a substrate, heating of plastic preforms, laser marking of plastics or paper. Various acrylic resins are used in coating formulations, for example, in laser welding of plastics. However, the acrylic resins used in US2010310787A1 are not suitable as insulating varnishes.

[0010]

[0010] Combinations of NIR absorbers and iodonium salts as co-initiators in combination with NIR-LEDs for NIR-enhanced polymerization of acrylic acid esters are described by Schmitz C. et al. (Progress in Organic Coatings 100 (2016), pp. 32-46). Cyanine is used as a preferred NIR absorber because of its flexibility in changing its structural pattern compared to other sensitizers such as rylene.

[0011]

[0011] Current wire coating processes require high energy sources and appropriate equipment such as furnaces. Therefore, it is desirable to develop wire coating compositions that can be applied and cured by appropriate equipment with lower energy consumption, for example, avoiding the use of furnaces. Furnaces also hinder inline production because heat dissipation usually occurs unevenly without a static distribution in space. Furthermore, maintenance work requires waiting until the equipment has cooled down to a temperature at which maintenance work can begin. In addition, a considerable amount of time is required to warm up the equipment until a nearly constant process temperature is available for production. These drawbacks result in a significant loss of production time, which is undesirable, especially for production facilities operating under lean production conditions. [Overview of the project] [Problems that the invention aims to solve]

[0012]

[0012] An object of the present invention is to provide a cost-effective method for covering and insulating electric wires. A further object of the present invention is to provide an insulating wire coating composition that is applied to electric wires and cured by irradiation. [Means for solving the problem]

[0013]

[0013] The object of the present invention is to be solved as described in the claims and herein.

[0014]

[0014] Specifically, the present invention is a method for covering and insulating electric wires, and the following: a) A step of coating an electric wire by applying a coating composition comprising an infrared-sensitive compound having maximum absorption in the wavelength range of 700 nm to 2,000 nm and a matrix containing insulating wire varnish, b) The step of exposing the insulated wire to an irradiation source, and c) A step of curing the coating of the electric wire to provide an enamel electric wire, This provides a method that includes [something].

[0015]

[0015] One embodiment of the present invention relates to the method described herein, wherein steps a) to c) are repeated until a desired enamel thickness is achieved.

[0016]

[0016] Further embodiments include an exposure source comprising a semiconductor that emits light in a spectral range of wavelengths from 700 nm to 2,000 nm. The method described herein relates to an exposure source which may be selected from semiconductor lasers and high-power LED devices.

[0017]

[0017] Further embodiments relate to the method described herein, wherein the infrared-sensitive compound is selected from the group consisting of polymethine, rylene, porphyrin, and / or oxonol.

[0018]

[0018] One embodiment of the present invention is a compound of formula (I), (II), (III), or (IV) in which case the polymethine is a compound of formula (I), (II), (III), or (IV).

[0019] [ka]

[0020] During the ceremony, Y is

[0021] [ka]

[0022] selected from Y’ is

[0023] [Chemical formula]

[0024] selected from A is H, C 1-6 alkyl, O-C 1-6 alkyl, barbituryl, aryl, N(Ph)2, S-phenyl, B and C are each independently H, C 1-6 alkyl, C 2-6 alkenyl; or, B and C together form a 5- or 6-membered carbocyclic ring, R 1 R 2 and R 3 are each independently H, C 1-3 alkyl, m and n each independently represent 0, 1, or 2, X - represents a counter anion, regarding the method described herein.

[0025]

[0019] A further embodiment relates to the method described herein, wherein the polymethine compound of formula (I), (II), (III), or (IV) exhibits a solubility in the matrix of at least 0.5 g / L at room temperature.

[0026]

[0020] A further embodiment relates to the method described herein, wherein the insulating wire varnish is selected from the group consisting of polyester, THEIC-modified polyester, polyesterimide, polyamideimide, polyimide, polyamide, polyurethane, polyvinyl formal, epoxy, acrylic resin, methacrylic resin, melamine resin, phenolic resin, and / or alkyd resin-based paints. Specifically, with the insulating wire varnish, the breakdown voltage of the enameled wire is at least 2 kV.

[0027]

[0021] According to one embodiment of the present invention, the solidification of the coating composition is influenced by variations in the substitution pattern of polymethine and / or variations in the counter-anions.

[0028]

[0022] Specifically, the present invention provides an insulating wire coating composition comprising an infrared-sensitive compound having maximum absorption in the wavelength range of 700 nm to 2,000 nm and a matrix containing insulating wire varnish.

[0029]

[0023] One embodiment of the present invention relates to a wire coating composition comprising an infrared-sensitive compound having maximum absorption in the wavelength range of 700 nm to 2,000 nm and a matrix containing varnish.

[0030]

[0024] Further embodiments relate to the wire coating compositions described herein, wherein the infrared-sensitive compound is selected from the group consisting of polymethine, rylene, porphyrin, oxonol, and carbon nanodots.

[0031]

[0025] Further embodiments include a compound of formula (I) where

[0032] [ka]

[0033] During the ceremony, Y is

[0034] [ka]

[0035] Selected from, Y' is

[0036] [ka]

[0037] Selected from, A is H, C1-6 Alkyl, OC 1-6 It represents alkyl, barbituryl, aryl, N(Ph)2, and S-phenyl. B and C are H and C respectively, independently. 1-6 Alkyl, C 2-6 Represents Alkenil; or B and C together form a 5-membered or 6-membered carbon ring. R 1 , R 2 and R 3 These are H and C, respectively, independently. 1-3 Represents alkyl, m and n each independently represent 0, 1, or 2. X - This specification relates to wire coating compositions, where represents a counter anion.

[0038]

[0026] Another embodiment relates to the wire coating composition described herein, wherein the polymethine compound of formula (I), (II), (III), or (IV) exhibits a solubility in a matrix of at least 0.5 g / L at room temperature.

[0039]

[0027] Further embodiments relate to the wire coating composition described herein, comprising a mixture of at least two infrared-sensitive compounds.

[0040]

[0028] Further embodiments relating to the wire coating compositions described herein, wherein the wire insulating varnish is a solid or liquid wire varnish. The varnish may be selected from the group consisting of polyester, THEIC-modified polyester, polyesterimide, polyamideimide, polyimide, polyamide, polyurethane, polyvinyl formal, epoxy, acrylic resin, methacrylic resin, melamine resin, phenolic resin, and / or alkyd resin-based paint. Specifically, the wire insulating varnish results in an dielectric breakdown voltage of at least 2kV for the enameled wire.

[0041]

[0029] Further embodiments relate to the wire coating compositions described herein, further comprising about 0.001% to about 80% volatile substances.

[0042]

[0030] Further embodiments relate to the wire coating compositions described herein, wherein the volatile substance is an aliphatic or aromatic carbohydrate compound.

[0043]

[0031] One embodiment of the present invention relates to an enameled wire comprising the curing coating composition described herein.

[0044]

[0032] Further embodiments relating to electric wires described herein, wherein the specifications of the cured coating composition are adapted by variations in the substitution pattern of polymethine and / or variations in the counter-anion.

[0045]

[0033] One embodiment of the present invention relates to the use of insulated wires in the electronics, automobile, aircraft, and / or adhesive industries. [Brief explanation of the drawing]

[0046] [Figure 1]

[0034] Coated wires that have been photonic dried using an NIR laser that emits light at 980 nm with a line-shaped focus (31 x 1.8 mm) showing an output of 300 W. Different absorbent concentrations were applied (T5-IV: 0.25 wt-%, T4-II: 0.5 wt-%, T4-VI: 0.5 wt-%, T6-IV: 1 wt-%). [Figure 2-1]

[0035] Photonic drying of the sample showing the first and second runs. This shows a glass transition (Tg) between 118°C and 136°C, while the Tg value appears at 127°C, and ΔCp is equal to 0.46 (J / g × K). Since there is no evidence of an exothermic effect, it can be seen that there are no residual monomers that contribute to the generation of reaction heat and the sample is completely dried. [Figure 2-2]

[0035] Photonic drying of the sample showing the first and second runs. This shows a glass transition (Tg) between 118°C and 136°C, while the Tg value appears at 127°C, and ΔCp is equal to 0.46 (J / g × K). Since there is no evidence of an exothermic effect, it can be seen that there are no residual monomers that contribute to the generation of reaction heat and the sample is completely dried. [Figure 3-1]

[0036] The progression of the curves indicates that the samples obtained by oven drying show similar data to the photonic drying samples shown in Figure 2. The Tg values ​​appear at almost the same temperature (126°C), again indicating that there is no significant difference between the techniques. The DSC methodology cannot definitively determine whether or not residual solvent remains in the treated coating, and to what extent. Both samples were analyzed by GC-MS (GS / MS-Varian 3900 & MS Saturn 2100T). Approximately 3 mg of sample was prepared for each investigation. The headspace agitator temperature was 199°C, which is its maximum temperature. The incubation time was 15 minutes. The obtained mass spectra were evaluated by comparison with the mass spectra of the reference (standard sample). [Figure 3-2]

[0036] The progression of the curves indicates that the samples obtained by oven drying show similar data to the photonic drying samples shown in Figure 2. The Tg values ​​appear at almost the same temperature (126°C), again indicating that there is no significant difference between the techniques. The DSC methodology cannot definitively determine whether or not residual solvent remains in the treated coating, and to what extent. Both samples were analyzed by GC-MS (GS / MS-Varian 3900 & MS Saturn 2100T). Approximately 3 mg of sample was prepared for each investigation. The headspace agitator temperature was 199°C, which is its maximum temperature. The incubation time was 15 minutes. The obtained mass spectra were evaluated by comparison with the mass spectra of the reference (standard sample). [Figure 4-1]

[0037] Comparison of GC / MS analysis (enamel oven vs. NIR). Both samples are shown, as well as standard materials and photonic dried samples. There is little residual solvent. Intensity is expressed in kilocounts, not megacounts. Therefore, applying either the conditions in Figure 2 or 3 results in very little residual solvent. Both samples show very high intensity levels for the same residual solvent components or the same amount of resist. The retention times of the detected components are 19-21 minutes and relate to cresol and phenol. These components are solvent components of the varnish. This confirms the DSC measurement. [Figure 4-2]

[0037] Comparison of GC / MS analysis (enamel oven vs. NIR). Both samples are shown, as well as standard materials and photonic dried samples. There is little residual solvent. Intensity is expressed in kilocounts, not megacounts. Therefore, applying either the conditions in Figure 2 or 3 results in very little residual solvent. Both samples show very high intensity levels for the same residual solvent components or the same amount of resist. The retention times of the detected components are 19-21 minutes and relate to cresol and phenol. These components are solvent components of the varnish. This confirms the DSC measurement. [Figure 5]

[0038] Recording of the temperature generated in the sample shown in Figure 1 (sample: T4-VI) using a thermal camera (Testo 885). [Modes for carrying out the invention]

[0047]

[0039] The present invention relates to a wire coating composition comprising an infrared-sensitive compound and a matrix having a varnish, a method for producing an enameled wire, and the use of the same.

[0048]

[0040] As used herein, “infrared-sensitive compound” or “absorbent” refers to a compound that exhibits an absorption maximum in the range of approximately 700 nm to 2,000 nm. Suitable absorbent compounds can be selected from the group consisting of polymethine, rylene, porphyrin, or carbon nanodots.

[0049]

[0041] The polymethine may be a compound of formula (I), (II), (III), or (IV),

[0050] [ka]

[0051] During the ceremony Y is

[0052] [ka]

[0053] Selected from, Y' is

[0054] [ka]

[0055] Selected from, A is H, C 1-6 Alkyl, OC 1-6 It represents alkyl, barbituryl, aryl, N(Ph)2, and S-phenyl. B and C are H and C respectively, independently. 1-6 Alkyl, C 2-6 Represents Alkenil; or B and C together form a 5-membered or 6-membered carbon ring. R 1 , R 2 and R 3 These are H and C, respectively, independently. 1-3 Represents alkyl, m and n each independently represent 0, 1, or 2. X - This represents the paired anion.

[0056]

[0042] Polymethine is

[0057] [ka]

[0058] [ka]

[0059] The compound may be selected from the group consisting of the following:

[0060]

[0043] Polymethine containing counterions

[0061] [ka]

[0062] The compound may be selected from the group consisting of the following:

[0063]

[0044] The counterion is a negatively charged group bonded to a positively charged polymerethine. The counterion of an anion may be monovalent (i.e., containing one formal negative charge). The counterion of an anion may be polyvalent, such as divalent or trivalent (i.e., containing multiple formal negative charges). An example of a counterion is a halide ion (e.g., F - Cl - , Br - , I - ) and NO3 - ClO4 - , O - HPO4 - , HCO3 - HSO4 - HSO3 - , sulfonate ions (e.g., methanesulfonate, trifluoromethanesulfonate, 4-dodecylbenzenesulfonate, etc.), carboxylate ions (e.g., acetate, propanoate, benzoate, etc.), BF4 - PF6 - , or BPh4 - , bis(trifluoromethanesulfonyl)imide ([(CF3SO2)2N] -Tetra(perfluoroalkoxy)aluminate, tetra(pentafluorophenyl)borate, or tris(pentafluoroethyl)trifluorophosphate ([PF3(C2F5)3]) are examples of tetra(perfluoroalkoxy)aluminates, tetra(pentafluorophenyl)borate, or tris(pentafluoroethyl)trifluorophosphate ([PF3(C2F5)3]), [Al(Ot-C4F9)]-]. - ) can be cited.

[0064]

[0045] Unless otherwise specified, the term "alkyl" when used alone or in combination with other groups or atoms refers to a saturated linear or branched chain consisting of only 1 to 6 hydrogen-substituted carbon atoms, and examples include methyl, ethyl, propyl, isopropyl, n-butyl, 1-methylpropyl, isobutyl, t-butyl, 2,2-dimethylbutyl, 2,2-dimethyl-propyl, n-pentyl, 2-methylpentyl, 3-methylpentyl, 4-methylpentyl, n-hexyl, etc.

[0065]

[0046] Unless otherwise specified, the term "alkenyl" refers to a partially unsaturated straight or branched chain consisting of only 2 to 6 hydrogen-substituted carbon atoms, including at least one double bond, and examples include vinyl, allyl, 2-methylpropaneyl, buta-1-enyl, buta-2-enyl, buta-3-enyl, buta-1,3-dienyl, penta-1,3-dienyl, penta-2,4-dienyl, 2-methylbuta-1-enyl, 2-methylpenta-1-enyl, 4-methylpenta-1-enyl, 4-methylpenta-2-enyl, 2-methylpenta-2-enyl, 4-methylpenta-1,3-dienyl, hexen-1-yl, etc.

[0066]

[0047] Unless otherwise specified, the term "carbocyclic ring" refers to a monocyclic group containing five or six carbon atoms. Carbocyclic rings may be partially saturated and may be substituted with one or more identical or different substituents. Examples of carbocyclic rings include cyclopentenyl and cyclohexanyl.

[0067]

[0048] Commercially available polymethine compounds can also be used. Suitable polymethine absorbent compounds are available from FEW Chemicals GmbH (Germany).

[0068]

[0049] Lylene is a dye based on a lylene framework of naphthalene units bonded at the peri position. In its homologues, additional naphthalene units are added to form compounds such as perylene, terylene, quaterylene, or poly(perinaphthalene). Porphyrins are a group of heterocyclic macrocyclic organic compounds consisting of four modified pyrrole subunits interconnected via methine crosslinks at α-carbon atoms.

[0069]

[0050] In one embodiment, the absorbent is a polymethine compound of formula (I), (II), (III), or (IV). It is also possible that the polymethine is related to an oxonol-based structure that contains a polymethine pattern in its molecular backbone.

[0070]

[0051] Wire enamel is applied to copper and aluminum round and rectangular wires used in motors, transformers, generators, the automotive industry, and electrical measuring instruments. The wire enamel is heated and cured on the wire. The main benefit of the resulting coating is electrical insulation. Wire enamel is also called primary insulator. Insulated wires are sometimes called "magnet wires".

[0071]

[0052] In literature or international standards, these are described using various terms such as electrical insulating varnish or electrical insulating material, as well as wire enamel.

[0072]

[0053] Electrical insulating varnishes play a special role under various varnishes because they insulate conductive carrier materials. Electrical insulation is an important function required to operate electric motors and transformers. Temperature resistance is even more important for safe continuous operation (Goldschmid A., Streitberger HJ., BASF-Handbuch Lackiertechnik.Vincentz:Hannover, 2002, ISBN:3-87870-324-4, p. 771).

[0073]

[0054] Electrical insulating materials typically separate and integrate carrier materials such as wires, electronic components, engines, transformers, and mechanical parts, without requiring any optical properties. (Brock T, Groteklaes M, Mischke P, Lehrbuch der Lacktechnologie, Vincentz, edition: 2, 1998, ISBN: 3-87870-569-7, p. 338).

[0074]

[0055] DIN EN60085:2008 defines electrical insulating material (EIM) as a solid or liquid material such as wire enamel, which has low electrical conductivity or is a simple combination of such materials, and is used to isolate conductive components having different potentials within an electrical device. Through wire enamel, a bare wire obtains an isolation surface.

[0075]

[0056] The solid insulating material may be used in processes such as extrusion molding or as insulating paper.

[0076]

[0057] The dielectric breakdown voltage is used to evaluate the insulating properties of a material. This must be done in accordance with IEC 60851-5, Chapter 4. Some companies define their own values ​​regarding the dielectric breakdown voltage that must be met. For example, some companies require that the dielectric breakdown voltage must always be 2kV or higher and that the increase in test voltage must not exceed 100V / s.

[0077]

[0058] In addition to dielectric breakdown voltage, insulating materials must also possess good thermal resistance characteristics. Standard DIN EN60034-1 defines the thermal resistance of insulating materials. The indicated temperature is the maximum value that a substance or material can withstand without changing its texture.

[0078]

[0059] There are no particular restrictions on the insulating varnish, but any insulating varnish used for conventional enameled wires can be used. Examples of conventionally used insulating varnishes include polyimide resin-based insulating varnish; polyesterimide resin-based insulating varnish; polyamideimide resin-based insulating varnish; and Class H polyester resin-based insulating varnish. The insulating coating 3 around the conductor wire 1 and the outermost insulating coating 4 may be made of the same material or different materials.

[0079]

[0060] According to one embodiment, the coating composition includes an insulating varnish. Any synthetic varnish commonly used for enameled wires can be used in the coating composition. Examples of conventionally used insulating varnishes, but not limited to, include polyaldehyde-modified or unmodified acetal, polyurethane, polyester, THEIC-modified polyester, polyesterimide, polyimide, polyamideimide, polyamide, polysulfone, polyimide resin, polyvinyl formal, epoxy, acrylic resin, methacrylic resin, melamine resin, phenolic resin and / or alkyd resin-based coatings or mixtures thereof. The choice of synthetic varnish depends on the heat resistance and insulating properties required for the coating layer.

[0080]

[0061] Particularly suitable varnishes are, for example, polyvinyl acetal-based insulating varnish systems. These varnish systems are reaction products of polyvinyl alcohol and aldehydes or ketones. Polyvinyl formal is produced by the reaction of formaldehyde with polyvinyl alcohol. The resulting polymer still contains residual ester groups produced by the hydrolysis of polyvinyl acetate to polyvinyl alcohol, as well as free OH groups that did not react with the aldehyde. Crosslinking reactions can occur via these free OH groups.

[0081]

[0062] Insulating varnishes useful in the present invention may be based on an unblocked and unprotected varnish portion, or a blocked or protected varnish portion. A blocked or protected varnish portion can be formed by reacting an unblocked and unprotected aldehyde portion with a suitable blocking or protecting group. Examples of aldehyde protecting or blocking groups are bisulfites (e.g., from the reaction of an aldehyde with sodium bisulfite), dioxolanes (e.g., from the reaction of an aldehyde with ethylene glycol), oximes (e.g., from the reaction of an aldehyde with hydroxylamine), and imines (e.g., from the reaction of an aldehyde with methylamine).

[0082]

[0063] In further embodiments of the present invention, cresol-blocked polyisocyanates or phenol-blocked polyisocyanates, phenol resins or urea resins, and melamine resins can be used as crosslinking agents. Furthermore, a single compound or a mixture thereof can be used as a crosslinking agent. The isocyanate component typically consists of an adduct of trimethylolpropane (TMP) and toluene diisocyanate (TDI), where the free isocyanate functional group is blocked by phenol or cresol. Cresol is typically used as a phenol resin, and hydroxymethyl derivatives of melamine (e.g., methyl ether or butyl ether) are typically used as melamine resins.

[0083]

[0064] The coating composition may further contain a volatile substance. As used herein, “volatile substance” means a substance that evaporates easily. Many organic compounds are volatile and can be used accordingly. In one embodiment of the present disclosure, the volatile substance is, for example, an aliphatic carbohydrate compound or aromatic carbohydrate compound such as phenol, cresol, xylol, or N-methyl-2-pyrrolidone (NMP).

[0084]

[0065] The volatile substances may be present in amounts of approximately 0.001 wt% to 85 wt%, or approximately 0.01 wt% to 70 wt%, or approximately 0.1 wt% to 50 wt%, or approximately 1 wt% to 30 wt%.

[0085]

[0066] The suitability of the coating composition to be solidified may depend on the substitution pattern of polymethine and / or counteranion. Therefore, different solidification properties of the coating composition can be achieved by changing the substitution patterns of polymethine and counteranion. As reported in RSC Advances 2015, 5(86):69915~69924, bis(trifluoromethylsulfonyl)imide has brought about a significant advance in improving the solubility of iodonium salts in varnish. Another alternative anion. The aluminate anion disclosed in ChemPhotoChem 2019, 3(11):1127~1132 represents another alternative. Furthermore, [PF3(C2F5)3] - Fluorinated alkyl phosphates, such as anions, present further opportunities. DE10357360A1, published as a FAP dye (FAP-Farbstoffe), represents a possible alternative. Yet another anion is associated with long-chain alkyl sulfonates (ChemPhotoChem 2017, 1(1):26-34), and it has been concluded that anions derived from weakly coordinating anions, such as those disclosed in The Journal of Organic Chemistry 2011, 76(2):391-395 and Angewandte Chemie 2004, 116(16):2116-2142, play the primary role. Borates present additional options.

[0086]

[0067] The coating composition may further contain a colorant. The colorant may be an inorganic pigment that provides a desired color. Specifically, the coating composition comprises (a) a synthetic varnish, (b) an absorbent compound, and optionally (c) an inorganic pigment, and (d) a volatile substance.

[0087]

[0068] Suitable inorganic pigments include metal oxides such as titanium dioxide, zinc oxide, ferric oxide, chromium(III) oxide, aluminum oxide, magnesium oxide, silicon oxide, tin oxide, and lead oxide; metal powders such as gold, silver, copper, and aluminum powders; carbon black and / or lead yellow. The type of inorganic pigment incorporated into the coating composition will depend on the desired color. In some embodiments, the inorganic pigment is titanium dioxide, chromium(III) oxide, aluminum oxide, and / or carbon black.

[0088]

[0069] One embodiment of the present invention relates to a method for coating an electric wire, comprising the steps of: applying a composition comprising an infrared-sensitive compound and a varnish, wherein the infrared-sensitive compound has maximum absorption in the wavelength range of 700 nm to 2,000 nm; exposing the coated electric wire to an irradiation source that matches the maximum absorption of the infrared-sensitive compound; and curing the coating layer.

[0089]

[0070] A laser or light-emitting diode (LED) can be used as the radiation source. The radiation source must coincide with the absorption maximum of the absorber. The absorber component is selected so that, when the coating composition is dried, significant absorption occurs in the range in which the radiation source will be used later. Specifically, the absorber exhibits an absorption maximum within that range. Therefore, if the radiosensitive element is to be dried by, for example, an IR laser, it is desirable that the absorber essentially absorbs radiation in the range of about 700 to 2,000 nm, and preferably exhibits an absorption maximum within that range.

[0090]

[0071] Laser-assisted processing is a well-known technique, particularly in polymer science. For example, liquid resins can be easily converted into solid polymer materials by simply exposing them to a laser beam for a short time. In this disclosure, a wet coating composition applied to an electric wire is dried by irradiation using infrared light.

[0091]

[0072] High-intensity light-emitting diodes (LEDs) can also be used. Here as well, the light generated by the LEDs is absorbed by the absorbent in the coating composition, which accelerates the drying process of the wet layer.

[0092]

[0073] The thickness of the dried varnish layer on enameled wires depends largely on their subsequent industrial use. The thickness of the varnish layer on enameled wires is typically in the range of about 10 to 100 μm, specifically in the range of about 30 to 50 μm. Several coating and drying steps may be required to obtain the desired thickness of the dried film.

[0093]

[0074] According to one embodiment of the present invention, the liquid coating composition is applied as a wet layer with a thickness of about 20 μm to 500 μm, and then irradiated. If the desired dry layer thickness is not achieved in a single process run, coating and drying are repeated until the desired dry layer thickness is achieved. Thus, this process can be performed as a single step, or it can be repeated up to 10 times to achieve the desired dry varnish layer thickness.

[0094]

[0075] In the case of a rectangular wire, the first (upper) side of the wire can be irradiated and dried. Then, the wire is rotated to the opposite side to dry the wet layer on the opposite side. In this way, the opposite side of the wire is preheated and reheating of the wire can be avoided. In such a process, photonic drying is started at a temperature higher than the ambient temperature, for example, about 50°C. Nevertheless, continuous processing requiring different conditions can also be applied.

[0095]

[0076] Therefore, in some cases, it may be advantageous to preheat the wire before irradiation. Preheating the wire promotes photonic drying, resulting in a uniform and smooth enamel layer.

[0096]

[0077] According to one embodiment of the present invention, a radiation source is fixedly mounted, and the coated wire passes near the wire, for example, by a belt. The speed of the belt has a significant effect on the drying of the wet layer coating composition. The speed adopted is determined by the number of photons that hit the coated wire, which leads to absorption, and therefore the number of photons that lead to heat generation in the drying process. The following formula is used to calculate an appropriate belt speed: s = d / t During the ceremony, s=speed [mm / s] d = distance [mm] t = time [s].

[0097]

[0078] The belt speed can be adjusted to match this. In some embodiments, the belt speed is in the range of 1 to 5 mm / s or 2 to 4 mm / s. In one embodiment, the belt speed is 3.33 mm / s.

[0098]

[0079] One embodiment of the present invention relates to an enameled wire in which the enamel is cured by irradiation. The specifications of the coating material can be adapted to the needs of the end user, for example, the coating can be specified to suit the industry and technology. The coating composition can be modified by incorporating polymethine compounds having different substitution patterns and using different counter-anions.

[0099]

[0080] Enameled wires must meet several conditions and values. Some companies define their own values ​​regarding the dielectric breakdown voltage that must be met. For example, the dielectric breakdown voltage must always be 2kV or higher, and the increase in test voltage must not exceed 100V / s. The dielectric breakdown voltage is determined by a standard test method, such as the ASTM / NEMA MW 1000 test method.

[0100]

[0081] The dielectric breakdown voltage mainly depends on the thickness of the insulator, but also on the diameter of the bare wire, the applied temperature, and the type of varnish.

[0101]

[0082] Enameled wires can be used in a variety of technical industrial fields, such as electronics, automobiles, aircraft, and / or adhesives. All industrial fields have different requirements for the enameled wires used. Current processes can be easily adapted to meet the above requirements. [Examples]

[0102]

[0083] The following embodiments are provided to aid in understanding the present invention and are not intended to limit the scope of the present invention, nor should they be interpreted as such.

[0103] Raw materials and methods

[0084] Polymethine (cyanine) is used as an NIR absorbent for photonic drying using an NIR LED or NIR laser (λ>700nm).

[0104]

[0085] The absorber is selected according to the LED and laser used. The absorbance maxima of the LEDs are 805 nm and 860 nm, respectively. Nevertheless, the laser emitted light at 980 nm. It is also possible to apply additional lasers with a linear focus that emit light at NIR wavelengths that overlap with the absorption spectrum of each absorber.

[0105]

[0086] The following are absorbents (polymethines) that absorb radiation from LEDs or lasers in this wavelength range. All absorbents are obtained from FEW Chemicals GmbH (Germany).

[0106] Analytical methods for characterizing photonically coated wires using LEDs and lasers

[0087] DSC-TA apparatus and GS / MS-Varian device are used to characterize enameled wires cured with NIR light. DSC (Differential Scanning Calorimetry) is used to measure residual solvent or incomplete crosslinking reaction (exothermic effect).

[0107]

[0088] Gas chromatography-mass spectrometry (GC-MS) analysis is recorded by headspace analysis on a Varian 3900 gas chromatograph equipped with a mass-selective ion trap detector. This analysis is compared to a standard sample as a relative method.

[0108] Belt speed

[0089] The speed of the belt plays a major role in drying the coating system. The speed ultimately determines how many photons hit the heat-generating system, which in turn leads to energy absorption by the absorbent.

[0109]

[0090] The belt speed is calculated according to the formula described herein.

[0110] [Table 1]

[0111] A belt speed of 3.33 mm / s will be used in all tests.

[0112] Example 1-S 0991 Laser Processing

[0091] S 0991 (1-butyl-2-(2-[3-[2-(1-butyl-1H-benzo[cd]indole-2-ylidene)-ethylidene]-2-phenyl-cyclohexa-1-enyl]-vinyl)-benzo[cd]indolium-4-dodecylbenzenesulfonate) is a polymethine compound having 4-dodecylbenzenesulfonate as a counteranion. S 0991 has the following structure.

[0113] [ka]

[0114]

[0092] The absorption maximum of S 0991 is at 980 nm.

[0115]

[0093] Wire enamel containing 0.5 wt% S 0991 absorbent was prepared. 50 mg of S 0991 and 10 g of lacquer based on polyvinyl acetal insulating varnish were mixed in a speed mixer at 2 × 3,000 rpm. The wire enamel was applied to a rectangular wire with a wet layer thickness of 30 μm and irradiated with a 980 nm, 300 W laser. Because the wet layer thickness was thin at 30 μm, an acceptable coating layer without blistering was obtained (see Figure 1).

[0116]

[0094] To fully characterize the properties of samples prepared by photonic drying, which involves processing materials by irradiation with light, differential scanning calorimetry-DSC (TA Instruments Q200) was used to obtain the required product parameters. In a crucible, the inventors placed approximately 1-2 mg of sample and exposed it to -20°C to +300°C (first run) or +200°C (second run) under a constant N2 flow and a heating rate of 10 K / min. As is evident from the DSC curve of the first run, an endothermic effect was observed in the temperature range of +20 to approximately 110°C. This is caused solely by moisture, as there is no solvent to evaporate in this temperature range. In the second run, as can be seen from Figure 2, the glass transition (Tg) is between 118°C and 136°C, with the Tg value appearing at 127°C and ΔCp equal to 0.46 (J / g°C). In the first run in Figures 2 and 3, there is no exothermic effect. This means that the system is completely dry.

[0117]

[0095] For the changes in light-dried samples, the inventors perform the same test using material dried in a standard enamel oven. As shown in Figure 3, the curve progression of that sample is very similar to that of the photonic-dried sample. The Tg values ​​are almost the same (126°C).

[0118]

[0096] Industrially used enameled wires require a final dry layer thickness of approximately 30-50 μm, so the drying process was repeated several times until a final acceptable coating layer without blistering was achieved (see Figure 1).

[0119] Example 2-S 2007 Laser Processing

[0097] S 2007 (1-butyl-2-(2-[3-[2-(1-butyl-1H-benzo[cd]indole-2-ylidene)-ethylidene]-2-diphenylaminocyclopenta-1-enyl]-vinyl)-benzo[cd]indolium tetrafluoroborate is a polymethine compound having tetrafluoroborate as a counteranion. S 2007 has the following structure.

[0120] [ka]

[0121]

[0098] The absorption maximum of S 2007 is approximately 996 nm.

[0122]

[0099] Wire enamel containing 0.5 wt% S 2007 absorbent was prepared. 50 mg of S 2007 and 10 g of lacquer based on polyvinyl acetal insulating varnish were mixed in a speed mixer at 2 × 3,000 rpm. Here, a coating containing groups related to blocked isocyanates that generate reactive groups during heat treatment was applied. The wire enamel was applied to a rectangular wire with a wet layer thickness of 30 μm and irradiated with a 980 nm, 300 W laser. Because the wet layer thickness was thin at 30 μm, an acceptable coating layer without blistering was obtained (see Figure 3). The drying process was repeated several times until the final dry layer thickness was obtained. No blistering was observed in the obtained final coating layer.

[0123] Example 3-S 2024-1 LED Processing

[0100] S 2024-1 (1-butyl-2-(2-[3-[2-(1-butyl-3,3-dimethyl-1,3-dihydro-indole-2-ylidene)-ethylidene]-2-phenylsulfanyl-cyclohexa-1-enyl]-vinyl)-3,3-dimethyl-3H-indroliumtetraphenylborate) is a polymethine compound having tetraphenylborate as a counteranion. S 2024-1 has the following structure.

[0124] [ka]

[0125]

[0101] The absorption maximum of S2024-1 is approximately 800 nm.

[0126]

[0102] To prepare wire enamel containing 0.5 wt% S2024-1 absorbent for use in photonic drying, 50 mg of S2024-1 and 10 g of lacquer based on polyvinyl acetal insulating varnish are mixed in a speed mixer at 2 × 3000 rpm. The wire enamel is applied to a rectangular wire with a wet layer thickness of 30 μm, and a linear focused light-emitting diode (LED) is used to measure at 805 nm and 1 W / cm². 2 The material was irradiated. Because the wet layer was thin, at 30 μm, an acceptable coating layer without blistering was obtained. The drying process was repeated six times to achieve a final dry layer thickness of 40 μm.

[0127] Example 4-S 2109 LED Processing

[0103] S 2109 (2-[2-[3-[2-(1,3-dihydro-1,3,3-trimethyl-2H-indole-2-ylidene)-ethylidene]-2-(1-phenyl-1H-tetrazole-5-ylsulfanyl)-1-cyclohexen-1-yl]-ethenyl]-1,3,3-trimethyl-3H-indroliumtetraphenylborate) is a polymethine compound having tetraphenylborate as a counteranion. S 2109 has the following structure.

[0128] [ka]

[0129]

[0104] The absorption maximum of S 2109 is approximately 800 nm.

[0130]

[0105] Wire enamel containing 0.5 wt% S0507 absorbent is prepared for use in photonic drying. 50 mg of S0507 and 10 g of lacquer based on polyvinyl acetal insulating varnish were mixed in a speed mixer at 2 × 3,000 rpm. The wire enamel was applied to a flat wire with a wet layer thickness of 30 μm, and measured with a linear focused light-emitting diode (LED) at 805 nm and 1 W / cm². 2 The material was irradiated. Because the wet layer was thin, at 30 μm, an acceptable coating layer without blistering was obtained. The drying process was repeated six times to achieve a final dry layer thickness of 40 μm.

[0131] Example 5 - Comparative Example

[0106] All experiments shown in Tables 1 and 2 used the same coating composition containing components assigned to blocked components that release reactive components during heat treatment. Details are disclosed in WO2011 / 015447A1 and are described in Lackformulierung und Lackrezeptur 2005, No. 2: pp. 146-158. The coating composition was applied to a copper substrate measuring 300 mm × 19.05 mm × 3.22 mm. The liquid film was then subjected to drying experiments.

[0132]

[0107] In the comparative experiment, the coated object was transferred to an oven operating at 230°C, and a processing rate of 20 cm / min and a residence time of 1.5 minutes were applied. Subsequently, the resulting dried film was analyzed in terms of glass transition temperature, and polymer formation was confirmed by DSC measurement (TA Instruments Q200, heating range: -20~300°C, -20~+200°C in the second run, heating rate: 10K / min, evaluation of exothermic reaction to confirm that all monomers were converted to polymer), GC-MS (GS / MS-Varian Varian3900 & MS Saturn2100T): • Capillary column: Innowax, 30m, 20M, film thickness 0.5μm • Vapor injection at 240℃, split 1:100 · Injection volume: 100μL • Stirrer temperature: 199℃ • Incubation time: 15 minutes • Carrier gas: Helium The amount of residual solvent was measured using this method.

[0133]

[0108] Since the desired performance can be obtained by this heat coating procedure, this example is used as a comparative example.

[0134] Example 6 - Photonic Drying

[0109] Next, the same coating composition was used for photonic drying. An NIR absorbent (0.25-1.0 wt%) was added to convert the absorbed light energy into heat that could initiate the chemical drying process. Table 1 shows the results obtained by applying a line-shaped focus that emitted at either 980 nm or 808 nm. The beam length was 50 cm and the dimensions were 31 mm × 1.8 mm. The experiment was carried out using these parameters.

[0135]

[0110] Figures 2 and 3 show the DSC curves obtained for Comparative Example 1 (Table 1) (Figure 2), which was dried in an enamel oven with three heating zones (400 / 420 / 440°C) and a residence time of 38 seconds, and for photonic drying (Figure 3) using the conditions of Experiment 2 in Table 1. There was no significant difference between the two samples, indicating that photonic drying using a linear laser worked well. Samples that are not completely dried typically exhibit an exothermic reaction in the heating range, resulting in a lower glass transition temperature.

[0136]

[0111] Analysis of residual volatile components showed similar patterns when considering both oven-dried samples and samples dried by the laser experiment described above. This once again demonstrates the success of chemical drying based on photonic techniques using an NIR laser with a linear focus. The results obtained are shown in Figure 4.

[0137]

[0112] For the evaluation of film formation, the following grading system was defined: 1 represents excellent, 2 represents good, 3 represents acceptable, 4 represents a film with some defects, and 5 represents an unacceptable result. As described below, these grading systems conform to the following criteria. • 1: The film was dry, non-sticky, contained low levels of volatile components, polymer formation was successful, the surface appearance was uniform, and film formation continued even after a short interruption of the process (10 minutes). 2: The film was dry, non-sticky, contained low levels of volatile components, polymer formation was successful, and the surface appearance was uniform. • 3: The film was dry, non-sticky, contained low amounts of volatile components (but more than defined for rating 2), polymer formation was successful, glass transition was low, and the surface appearance was uniform. • 4: The film was dry, non-sticky, contained significantly high levels of volatile components as defined in rating 3, polymer formation was incomplete, and the surface appearance was partially uneven. 5: The film was not dry.

[0138] [Table 2-1]

[0139] [Table 2-2]

[0140] [Table 2-3]

[0141] [Table 2-4]

[0142] [Table 2-5]

[0143] [Table 2-6]

[0144] [Table 2-7]

[0145] [Table 2-8]

[0146] [Table 2-9]

[0147] Example 7 - Use of High-Power LED Devices

[0113] As an alternative, novel high-power LED devices were applied to photonic drying. They exhibit emission at 808 nm and 860 nm, respectively, representing new advances in this field as shown in Schmitz C. et al., Angew. Chem. Int. Ed. 2019, 58, (13) pp. 4400-4404 and Pang Y. et al., Angew. Chem. Int. Ed. 2020, 59, (28) pp. 11440-11447. Their power density of 8 W / cm² enables the system to operate. 2 While values ​​were shown, it was not possible to apply a weak light-emitting LED (Schmitz C. et al., Progress in Organic Coatings 2016, 100, pp. 32-46). Experiments emitting light at 940 nm included an additional high-power NIR-LED. The formation of solid films by each polymer formation can be considered a major advance in this field. Applying a more powerful light-emitting LED reduces processing time. The results are shown in Table 2.

[0148]

[0114] Once the absorbent had released sufficient heat, the success of the drying process was monitored using a thermal sensing camera (testo 885-thermal camera) (see Figure 5).

[0149] [Table 3-1]

[0150] [Table 3-2]

[0151] [Table 3-3]

[0152] [Table 3-4]

[0153] [Table 3-5]

[0154] Table 3-6

[0155] Table 3-7

[0156] Table 3-8

[0157] Table 3-9 Specific embodiments of the present invention are as follows. [Aspect 1] A method of covering and insulating electric wires, the following: a) A step of coating the electric wire by applying a coating composition comprising an infrared-sensitive compound having maximum absorption in the wavelength range of 700 nm to 2,000 nm and a matrix containing insulating wire varnish, b) The step of exposing the insulated wire to an irradiation source, and c) A step of curing the coating of the electric wire to provide an enamel electric wire, A method that includes this. [Aspect 2] The method according to embodiment 1, wherein steps a) to c) are repeated until a desired enamel thickness is achieved. [Aspect 3] The method according to embodiment 1 or 2, wherein the irradiation source for exposure includes a semiconductor that emits light in a spectral range of wavelengths from 700 nm to 2,000 nm. [Aspect 4] The method according to embodiment 3, wherein the irradiation source is selected from a semiconductor laser and a high-power LED device. [Aspect 5] The method according to any one of embodiments 1 to 4, wherein the infrared-sensitive compound is selected from the group consisting of polymethine, rylene, porphyrin, and / or oxonol. [Aspect 6] The polymethine is a compound of formula (I), (II), (III), or (IV),

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Claims

1. A method of covering and insulating electric wires, the following: a) A step of coating the electric wire by applying a coating composition comprising an infrared-sensitive compound having maximum absorption in the wavelength range of 700 nm to 2,000 nm and a matrix containing insulating wire varnish, b) The step of exposing the insulated wire to an irradiation source, c) The step of curing the coating of the electric wire to provide an enamel electric wire, Includes, A method wherein the infrared-sensitive compound is polymethine.

2. The method according to claim 1, wherein steps a) to c) are repeated until a desired enamel thickness is achieved.

3. The method according to claim 1 or 2, wherein the irradiation source for exposure includes a semiconductor that emits light in a spectral range of wavelengths from 700 nm to 2,000 nm.

4. The method according to claim 3, wherein the irradiation source is selected from a semiconductor laser and a high-power LED device.

5. The polymethine is a compound of formula (I), (II), (III), or (IV), 【Chemistry 1】 During the ceremony, Y 【Chemistry 2】 Selected from, Y' 【Transformation 3】 Selected from, A is H, C １－６ Alkyl, O-C １－６ Alkyl, barbituryl, aryl, N(Ph) ２ , represents S-phenyl, B and C are H and C, respectively, independently. １－６ Alkyl, C ２－６ Represents Alkenil; or B and C combine to form a five-membered or six-membered carbon ring. R １ 、 R ２ and R ３ each independently represents H, C １－３ alkyl, m and n each independently represent 0, 1, or 2. X － The method according to claim 1, wherein represents a pair anion.

6. The method according to claim 5, wherein the polymethine compound of formula (I), (II), (III), or (IV) exhibits a solubility in the matrix of at least 0.5 g / L at room temperature.

7. The method according to any one of claims 1 to 6, wherein the insulating wire varnish is selected from the group consisting of polyester, THEIC-modified polyester, polyesterimide, polyamideimide, polyimide, polyamide, polyurethane, polyvinyl formal, epoxy, acrylic resin, methacrylic resin, melamine resin, phenolic resin, and / or alkyd resin-based coatings.

8. The method according to claim 7, wherein the dielectric breakdown voltage of the enamel wire is at least 2 kV due to the insulating wire varnish.

9. The method according to any one of claims 1 to 8, wherein the solidification of the coating composition is influenced by variations in the substitution pattern of the polymethine and / or variations in the counter-anion.

10. A wire coating composition comprising an infrared-sensitive compound having maximum absorption in the wavelength range of 700 nm to 2,000 nm and a matrix containing insulating wire varnish, wherein the infrared-sensitive compound is polymethine.

11. The polymethine is a compound of formula (I), (II), (III), or (IV), 【Chemistry 4】 During the ceremony, Y 【Transformation 5】 Selected from, Y' 【Transformation 6】 Selected from, A is H, C １－６ Alkyl, O-C １－６ Alkyl, barbituryl, aryl, N(Ph) ２ , represents S-phenyl, B and C are H and C, respectively, independently. １－６ Alkyl, C ２－６ Represents Alkenil; or B and C combine to form a five-membered or six-membered carbon ring. R １ , R ２ and R ３ However, H and C are independent of each other. １－３ Represents alkyl, m and n each independently represent 0, 1, or 2. X － The wire coating composition according to claim 10, wherein represents a counter anion.

12. The wire coating composition according to claim 11, wherein the polymethine compound of formula (I), (II), (III), or (IV) exhibits a solubility in the matrix of at least 0.5 g / L at room temperature.

13. A wire coating composition according to any one of claims 10 to 12, comprising a mixture of at least two infrared-sensitive compounds.

14. The wire coating composition according to any one of claims 10 to 13, wherein the insulating wire varnish is a solid or liquid wire varnish.

15. The wire coating composition according to claim 14, wherein the insulating wire varnish is selected from the group consisting of polyester, THEIC-modified polyester, polyesterimide, polyamideimide, polyimide, polyamide, polyurethane, polyvinyl formal, epoxy, acrylic resin, methacrylic resin, melamine resin, phenolic resin, and / or alkyd resin-based coatings.

16. The wire coating composition according to claim 14 or 15, wherein the insulating wire varnish causes the dielectric breakdown voltage of the enamel wire to be at least 2 kV.

17. Use of the wire coating composition according to any one of claims 10 to 16 in the method according to any one of claims 1 to 9.

18. An enameled wire comprising the cured coating composition according to any one of claims 10 to 17.

19. The enameled wire according to claim 18, having an dielectric breakdown voltage of at least 2 kV.

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