KR102803895B1 - UV curable car refinish filler paint and method of automobile maintenance using the same - Google Patents

Abstract

A technology relating to a UV-curable automotive repair filler paint and an automotive repair method using the same, the technology comprising a composition comprising 5 to 35 wt% of a UV-curable urethane acrylate oligomer resin, 35 to 75 wt% of a polyfunctional acrylate monomer and a monofunctional acrylate monomer, 1 to 10 wt% of a photoinitiator, 0.5 to 5 wt% of a UV curing accelerator, and a residual pigment.

Description

UV curable car refinish filler paint and method of automobile maintenance using the same. {UV curable car refinish filler paint and method of automobile maintenance using the same}

The present invention relates to a UV-curable automotive refinish filler paint capable of thick-film coating and an automotive refinishing method using the same, and more specifically, to a automotive refinish filler paint capable of curing a thick film of 2,000 ㎛ or more within 1 minute of UV irradiation, having excellent adhesion and water resistance and excellent polishing properties, and being applicable to both a body filler coating process and a surfacer coating process by integrating existing body fillers and surfacers, and to an automotive refinishing method using the same.

At a time when corporate ESG management for sustainable growth is gaining prominence worldwide, the development of eco-friendly, low-carbon paints has become more important than ever, and automotive refinish paints are no exception, so demand for eco-friendly, low-carbon automotive refinish paints is rapidly increasing.

Automotive refinish paints can be broadly divided into the following three types. First, there is body filler (or putty, putty filler, stopper, putty stopper, stopper filler, hereinafter collectively referred to as body filler; concept of undercoat) refinish paint for filling in the unevenness of sheet metal areas, damaged body areas, and the old paint film painted on the body and bumpers, etc. Second, there is surfacer (or primer, primer filler, primer surfacer, hereinafter collectively referred to as surfacer; concept of intermediate coat) refinish paint for filling in fine curves or pinholes after the body filler and providing smoothness between the old paint film and the body filler, while improving the adhesion to the top coat and the appearance of the top coat. Third, there is topcoat (base coat-clear coat system or mono coat system, hereinafter collectively referred to as top coat; concept of top coat) paint that provides the final color while imparting gloss and durability.

The first basecoat, body filler, is an unsaturated polyester system that uses peroxide initiator as a hardener worldwide. However, it requires a curing time of 20 to 30 minutes at room temperature, and the remaining paint after mixing must be disposed of as waste. In addition, there is a problem that the paint contains styrene monomer, a toxic substance.

The second intermediate paint, surfacer, is again divided into one-component and two-component types. The two-component surfacer requires a relatively long curing time of 60 to 90 minutes at room temperature, but has excellent adhesion and water resistance, whereas the one-component surfacer requires only a curing time of 10 to 20 minutes at room temperature, but has relatively poor adhesion and water resistance.

Here, a new system that has excellent adhesion and water resistance and can be cured in a matter of seconds to minutes without the need for separate heat treatment, thereby shortening productivity and process speed (low carbon) and eliminating waste paint left after use by mixing the main agent and the curing agent (eco-friendly) is a coating method that cures with UV (ultraviolet rays). Regarding this technology, Korean Patent No. 10-0872525 discloses a curable resin for putty and a UV-curable putty composition using the same. In the case of the composition according to the invention, the intended purpose can be achieved in a thin film of 100㎛ or less, but in a thick film of 2,000㎛ or more to fill in the unevenness of the sheet metal area, internal curing is not complete, so the adhesion to the substrate is poor and there is a problem of it getting caught in the abrasive paper during polishing, making it difficult to apply in actual fields.

Therefore, there is a need to develop a UV-curable body filler that can be practically used in automobile repair sites, with excellent adhesion, water resistance, and polishing properties, while enabling automotive thick-film painting of 2,000㎛ or more, with a short UV exposure time of less than 1 minute.

1. Korean Patent Registration No. 10-0872525

In order to solve the above problems, the present invention provides a UV-curable automobile refinish paint that can be applied to a UV-curable body filler paint that has no pores in the film, enables a thick film coating of 2,000 ㎛ or more, has a short UV irradiation time of less than 1 minute, has excellent adhesion and water resistance, and has excellent polishing properties.

In addition, the present invention provides an automobile repair method capable of forming a non-porous base coating film using a medium- and low-temperature integrated UV-curable automobile repair filler paint that can be used as a body filler or a surfacer as a single composition without distinction between body filler and surfacer.

A UV-curable automotive refinish filler paint according to one embodiment of the present invention may include 5 to 35 wt% of a UV-curable urethane acrylate oligomer resin formed by addition reaction of 20 to 80 wt% of polyester or polyether polyol, 10 to 40 wt% of diisocyanate, and 10 to 40 wt% of a photocurable monomer, 35 to 75 wt% of a polyfunctional acrylate monomer and a monofunctional acrylate monomer, 1 to 10 wt% of a photoinitiator, 0.5 to 5 wt% of a UV curing accelerator, and a residual pigment.

A UV-curable automotive repair filler paint according to another embodiment of the present invention may include 5 to 35 wt% of a UV-curable epoxy acrylate oligomer resin formed by esterifying 50 to 80 wt% of an epoxy resin, 20 to 50 wt% of acrylic acid or methacrylic acid, and 0.05 to 0.2 wt% of a polymerization inhibitor, 35 to 75 wt% of a polyfunctional acrylate monomer and a monofunctional acrylate monomer, 1 to 10 wt% of a photoinitiator, 0.5 to 5 wt% of a UV curing accelerator, and a residual pigment.

According to one embodiment, the automotive refinish filler paint has a viscosity of 50 to 70 KU at 25°C, a specific gravity of 1.10 to 1.50 at 25°C, a particle size of 5 to 7 NS in terms of Hegman gauge, and is capable of being spray-coated, so that it is applicable to both a body filler process and a surfacer process for forming an automotive refinish film. No pores exist in the refinish film formed in this manner.

An automobile repair method according to one embodiment of the present invention includes a step of spraying an automobile repair filler paint onto a surface of an object on which an automobile repair film is to be formed, while simultaneously irradiating ultraviolet rays to form a repair film, and a step of polishing the surface of the object on which the repair film is formed.

In one embodiment, the automobile repair method may further include the step of forming a topcoat covering the repair film.

According to the present invention, the UV-curable automotive refinish filler paint according to the present invention is very environmentally friendly as it has a volatile organic compound (VOC) content of less than 50 g/l, which causes air pollution, and can be painted with a thick film of about 2,000 ㎛ or more by spray painting, so that it can be applied identically in actual automotive refinishing sites, and the curing time, which is 20 to 30 minutes at room temperature drying without a separate heat treatment process, is shortened to about 1 minute through UV curing, so that productivity and process speed can be dramatically improved. In addition, the paint does not contain styrene monomer, which is a toxic substance, so that it is user-friendly, and has an economical advantage as no paint waste remains after use. In addition, as a filler paint integrating body filler and surfacer, it can be applied to both the body filler process and the surfacer process with one product, so that user convenience is improved and inventory management is easy.

In this application, the terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as the second component, and similarly, the second component may also be referred to as the first component.

The terminology used in this application is only used to describe specific embodiments and is not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this application, it should be understood that the terms "comprises" or "has" and the like are intended to specify the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but do not exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

UV curable automotive refinish filler paint

A UV-curable automotive repair filler paint according to one embodiment of the present invention comprises a UV-curable urethane acrylate oligomer resin, a multifunctional acrylate monomer and a monofunctional acrylate monomer, a photoinitiator, a UV curing accelerator, and a pigment.

Specifically, the UV-curable automotive repair filler paint has a composition including 5 to 35 wt% of a UV-curable urethane acrylate oligomer resin, 35 to 75 wt% of a polyfunctional acrylate monomer and a monofunctional acrylate monomer, 1 to 10 wt% of a photoinitiator, 0.5 to 5 wt% of a UV curing accelerator, and an additional pigment.

The above UV-curable urethane acrylate oligomer resin is formed by addition reaction of 20 to 80 parts by weight of polyester or polyether polyol, 10 to 40 parts by weight of diisocyanate, and 10 to 40 parts by weight of photocurable monomer. At this time, a catalyst and a polymerization inhibitor can be additionally used as additives.

Examples of the above diisocyanates include isophorone diisocyanate, 2,4-toluene diisocyanate and isomers thereof, hexamethylene diisocyanate, 2,2-bis-4'-propane diisocyanate, m-phenylene diisocyanate, 1,5-naphthalene diisocyanate, 1,4-xylene diisocyanate, 1,3-xylene diisocyanate, isophorone diisocyanate, 1,5-naphthalene diisocyanate, 6-isopropyl-1,3-phenyl diisocyanate, 1,6-hexanediisocyanate, 4,4'-biphenylene diisocyanate, 3,3'dimethylphenylene diisocyanate, 3,3'-dimethyl-4,4'-diphenylmethane diisocyanate, p-phenylene diisocyanate, Examples include 1,4-xylene diisocyanate and 1,3-xylene diisocyanate. These can be used alone or in combination of two or more.

Examples of the photocurable monomers include 2-hydroxyethyl acrylate, pentaerythritol tri(meth)acrylate, 4-hydroxybutylacrylate, hydroxypropyl acrylate, 2-hydroxypropyl(meth)acrylate, 2-hydroxyethyl(meth)acrylate, etc. Two or more of these can be used together.

As an example, UV-curable urethane acrylate oligomer resins applied to UV-curable automotive refinish filler paints are used in the range of 5 to 35 wt%. If used less than 5 wt%, the curing property of the coating film becomes slow, resulting in poor material adhesion. If used in excess of 35 wt%, the viscosity of the paint becomes too high, resulting in poor spray workability.

Examples of the multifunctional acrylate monomer applicable to the paint of the above embodiment include trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, ethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, trimethylolpropane trioxyethyl(meth)acrylate, tripropylene glycol di(meth)acrylate, and tricyclodecane dimethanol di(meth)acrylate, and these may be used alone or in combination of two or more.

Examples of the monofunctional acrylate monomer applied to the paint of the above embodiment include diethylaminoethyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, t-octyl (meth)acrylate, N,N-dimethyl (meth)acrylate, N-vinylcaprolactam, N-vinylpyrrolidone, isobutoxy (meth)acrylamide, diacetone (meth)acrylamide, bornyl (meth)acrylate, isobornyl (meth)acrylate, N,N-dimethylacrylamide, ethoxyethoxyethyl (meth)acrylate, methoxyethylene glycol (meth)acrylate, polypropylene glycol mono (meth)acrylate, polyethylene glycol mono (meth)acrylate, phenoxyethyl (meth)acrylate, cyclohexyl (meth)acrylate, Benzyl (meth)acrylate, epoxydiethylene glycol (meth)acrylate, butoxyethyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, styryl (meth)acrylate, octadecyl (meth)acrylate, lauryl (meth)acrylate, dodecyl (meth)acrylate, isodecyl (meth)acrylate, nonyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isoamyl (meth)acrylate, t-butyl (meth)acrylate, isobutyl (meth)acrylate, tricyclodecanyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentadiene (meth)acrylate, methoxypolypropylene glycol (meth)acrylate, Examples include methoxypolyethylene glycol (meth)acrylate, butyl (meth)acrylate, isopropyl (meth)acrylate, propyl (meth)acrylate, ethyl (meth)acrylate, and methyl (meth)acrylate, and they can be used alone or in combination of two or more.

If the amount of the above multifunctional acrylate monomer and monofunctional acrylate monomer used is less than 35 wt%, the viscosity increases, resulting in a problem of reduced workability, and if the amount of the above multifunctional acrylate monomer and monofunctional acrylate monomer used exceeds 75 wt%, the content of the extender pigment in the pigment decreases, resulting in a problem of reduced polishability and sealability of the formed coating film.

The paint of the present invention contains 1 to 10 wt% of a photoinitiator that initiates an initiation reaction by UV irradiation. If the photoinitiator is used in an amount of less than 1 wt% based on the total weight of the UV-curable automotive repair filler paint, UV curability is reduced, and if it is used in an amount exceeding 10 wt%, the storage stability of the paint is reduced, residual photoinitiator may act as an impurity, and there are problems in that the cost significantly increases.

Examples of the photoinitiator include 1-hydroxycyclohexylphenyl ketone, 2,2-dimethoxy-2-phenyl-acetophenone, benzaldehyde, anthraquinone, 3-methylacetophenone, 4-chlorobenzophenone, 4,4′-dimethoxybenzophenone, benzoin propyl ether, benzoin ethyl ether, 1-(4-isopropyl-phenol)-2-hydroxy-2-methylpropan-1-one, thioxanthone, benzophenone, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, and the like, and they may be used alone or in combination of two or more.

Also, examples of commercially supplied photoinitiator products include Irgacure184, 651, 500, 819, 907, 1800 (BASF), Darocure 1116, 1173 (Merck), Lucirine LR8728 (BASF), Micure HP-8, TPO, CP-4, BK-6 (Miwon specialty chemical), and also benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylaminoacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, One selected from the group consisting of 1-hydroxycyclohexylphenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-propan-1-one, 4-(2-hydroxyethoxy)phenyl-2(hydroxy-2-propyl)ketone, benzophenone, p-phenylbenzophenone, 4,4'-diethylaminobenzophenone, dichlorobenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tertiary-butylanthraquinone, 2-amino anthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzyldimethyl ketal, acetophenonedimethyl ketal and p-dimethylaminebenzoic acid ester, or A mixture of two or more types can be used, and the cationic polymerization type photoinitiator can be a compound combining one or more types of anions such as aromatic oxosulfonium ion, aromatic iodonium ion, and tetrafluoroborate, hexafluorophosphate, hexafluoroantimonate, and hexafluoroarsenate.

The UV curing accelerator is preferably included in an amount of 0.5 to 5 wt% based on the total amount of the paint to eliminate the oxygen hindrance effect occurring in the paint film during the UV curing reaction and to promote the reaction between the photoinitiator, oligomer, and monomer in order to obtain a paint capable of curing a high filling film thickness of 2,000 ㎛ or more within 1 minute, which is a feature of the present invention.

If the content of UV curing accelerator is less than 0.5 wt%, the accelerator function may be insufficient, which may cause poor curing, and if it exceeds 5 wt%, there is a problem of increased price due to excessive accelerator.

The above UV curing accelerator may be used as one or a combination of two or more of 3-mercaptopropionate, triethyldiamine, triethylethanolamine, 1,4-diazocyclooctane, 2-dimethylaminoethyl, trimethylaminoethylethanolamine, pentamethyldiethylenetriamine, dimethylethanolamine, ethylmorphyline, dimethylaminoethylmorpholine, dimethylcyclohexylamine, alkaline aromatic sulfonic acid, alkyl naphthalene sulfonic acid, ethylene glycol bisthioglycolate, pentaerythritol tetrakis, and trimethylolpropane tris. Commercially available amine hydrogen donors and acrylated amine synergists copolymerized with 3-mercaptopropionate include ST-041AC (SHIN-A T&C), Ebecryl P-115 (ALLNEX), Miramer ES-100, ES-110N, AS-2010 (Miwon specialty chemicals). In particular, in the present embodiment, it is more preferable to select and use 3-mercaptopropionate or an amine synergist as the UV curing accelerator.

The pigment applied to the automobile maintenance filler paint of the present invention may include at least two or more of a color pigment, a rust-preventive pigment, and an extender pigment. As an example, the extender pigment may be at least two or more of talc, calcium carbonate, barium sulfate, and kaolin, and the color pigment may be at least one of titanium dioxide and carbon black.

The amount of pigment applied to the filler paint for automobile maintenance can be used within the content range excluding the amount of acrylate oligomer resin, polyfunctional acrylate monomer and monofunctional acrylate monomer, photoinitiator, and UV curing accelerator based on the total weight of the entire paint. As an exemplary embodiment, if the amount of pigment used is less than 15 wt% based on the total sum of the paint, the abrasiveness and filling properties deteriorate, and if it exceeds 40 wt%, the viscosity increases, which causes a problem of deterioration in workability.

Commercially available body pigments include, for example, talc NA-collector#400, NA-1250, SA-400, KA-400 (Youngwoo Resources Co., Ltd.), TA-400, TA-800 (Rexem Co., Ltd.), KCNAP-400, KCM-6300, KCAS-400, KG-2000 (Coats Co., Ltd.), calcium carbonate SN-7000 (Seongshin Minefield Co., Ltd.), Omyacoat 420IP, Omyacarb 1T, Calcium-H, Calcium-E (OMYA Korea), CM-1, CM-5 (Chungmu Chemical), and barium sulfate Baryte powder NB-0030 (Korea Semiconductor Materials), Baryte NO.325 (LVS Pigment), Barytes B20 (Viaton), Blanc fixe micro (Huntsman), etc. Kaolin includes Calcined kaolin TZJ-1 (Inner Mongolia Tianzhijiao kaolin Co.,LTD), Antec C-OP (Anpeak specialty minerals), SBM 400 china clay (Daesungche), Kamin 70C (J.M Huber CO.), Polestar 400 (Imerts), ASP-102, ASP-170, ASP-600, ASP-900, Satintone 5, Satintone W, Satintone HB (BASF), etc.

According to an exemplary embodiment, the paint of the present invention may be used by additionally mixing additives such as an antioxidant, a light stabilizer, a silane coupling agent, a heat polymerization inhibitor, a leveling agent, a dispersant, a phosphate-based adhesion promoter, an anti-settling agent, and an organic solvent to obtain a required viscosity, as needed.

A UV-curable automotive refinish filler paint according to another embodiment of the present invention comprises a UV-curable epoxy acrylate oligomer resin, a multifunctional acrylate monomer and a monofunctional acrylate monomer, a photoinitiator, a UV curing accelerator, and a pigment.

Specifically, the UV-curable automotive repair filler paint has a composition including 5 to 35 wt% of a UV-curable epoxy acrylate oligomer resin, 35 to 75 wt% of a polyfunctional acrylate monomer and a monofunctional acrylate monomer, 1 to 10 wt% of a photoinitiator, 0.5 to 5 wt% of a UV curing accelerator, and an additional pigment.

At this time, the UV-curable epoxy acrylate oligomer resin is formed by esterification reaction of 50 to 80 parts by weight of an epoxy resin, 20 to 50 parts by weight of acrylic acid or methacrylic acid, and 0.05 to 0.2 parts by weight of a polymerization inhibitor. At this time, a catalyst may be additionally used as an additive.

Examples of the above epoxy resins include Miramer PE210, Miramer PE250, Miramer PE6300 of Miwon Specialty Chemical Co., Ltd., or M6-0270, N3-0285 of Noroo Paint. These can be used alone or in combination of two or more. These can be used alone or in combination of two or more.

As an example, UV-curable epoxy acrylate oligomer resins applied to UV-curable automotive refinish filler paints are used in the range of 5 to 35 wt%. If they are used in amounts less than 5 wt%, the strength of the coating film decreases, resulting in poor material adhesion. If they are used in amounts exceeding 35 wt%, the strength of the coating film becomes too high, resulting in poor polishing workability.

The monofunctional acrylate monomer and the polyfunctional acrylate monomer applied to the above UV-curable automotive repair filler paint are used to dilute the UV-curable epoxy acrylate oligomer resin. Since their types have been specifically described in the paint of the above example, they have been omitted to avoid duplication. The specific description of the types and usage amounts of the photoinitiator, UV curing accelerator, pigment, etc. have also been specifically described in the paint of the above example, and thus have been omitted to avoid duplication.

The automotive refinish filler paint having the composition described above is formed by dispersing the paint so that it can be applied to both a body filler process and a surfacer process. The dispersed paint has a viscosity of 50 to 70 KU at 25°C, a specific gravity of 1.10 to 1.50 at 25°C, a particle size of 5 to 7 NS in terms of the Hegman gauge, and is capable of being spray-painted, so that it can be applied to both the body filler process and the surfacer process for forming an automotive refinish paint film, and is characterized by having no pores in the film formed thereby.

Car maintenance methods

The method for repairing an automobile using the automobile repair filler paint of the present invention comprises the steps of spraying a UV-curable automobile repair filler paint onto the surface of an object on which an automobile repair film is to be formed, simultaneously irradiating the surface with ultraviolet rays to form a repair film, and polishing the surface of the object on which the repair film is formed.

As an example, the UV-curable automotive repair filler paint applied to the above repair method may be an automotive repair filler paint having a composition including 5 to 35 wt% of a UV-curable urethane acrylate oligomer resin, 35 to 75 wt% of a polyfunctional acrylate monomer and a monofunctional acrylate monomer, 1 to 10 wt% of a photoinitiator, 0.5 to 5 wt% of a UV curing accelerator, and a residual pigment. At this time, the UV-curable urethane acrylate oligomer resin is formed by addition reaction of 20 to 80 wt% of polyester or polyether polyol, 10 to 40 wt% of diisocyanate, and 10 to 40 wt% of a photocurable monomer.

As another example, the UV-curable automotive repair filler paint applied to the above repair method may be an automotive repair filler paint having a composition including 5 to 35 wt% of a UV-curable epoxy acrylate oligomer resin, 35 to 75 wt% of a polyfunctional acrylate monomer and a monofunctional acrylate monomer, 1 to 10 wt% of a photoinitiator, 0.5 to 5 wt% of a UV curing accelerator, and a residual pigment. At this time, the UV-curable epoxy acrylate oligomer resin is formed by esterification reaction of 50 to 80 wt% of an epoxy resin, 20 to 50 wt% of acrylic acid or methacrylic acid, and 0.05 to 0.2 wt% of a polymerization inhibitor.

Specific details regarding the composition and content of the UV-curable automotive repair filler paint are sufficiently described in the text above, and are therefore omitted to avoid duplication.

As an example, it is preferable that the repair film to be formed using the above paint be formed to a thickness of 1,500 to 2,000 μm. The repair film thus formed does not contain pores.

As an example, the step of forming the above-mentioned filling repair film corresponds to the body filler painting step in the step of forming the automobile paint film.

In addition, in order to obtain the characteristics of the present invention described above, the paint provided by the present invention is characterized in that it is painted by spraying with a general spray gun used in automobile repair painting, rather than forming a film by applying with a conventional spatula or applicator. (For example, SATA 5000 RP gun, nozzle diameter 1.3 mm to 1.8 mm, air pressure 1.6 bar to 2.5 bar) Specifically, the automobile repair filler paint according to one embodiment of the present invention preferably has a viscosity of about 50 to 70 KU at about 25°C in order to secure the process conditions for spray painting.

In addition, the ultraviolet irradiation for forming the above-mentioned repair film uses a specific UV irradiator, and uses an LED lamp type UV irradiator instead of a conventional mercury gas discharge lamp. More specifically, it is characterized by using an irradiator having a light source that mainly generates wavelengths between 340 nm and 450 nm.

This is because, in order to completely cure a film of about 2,000㎛ all the way to the inside, an ultraviolet wavelength with excellent penetrability is required, and the above wavelength range is the most ideal. In order to mainly generate such a specific wavelength, it is difficult to do so with a conventional mercury gas discharge lamp, and an LED type lamp must be used.

By using this type of probe, it can be easily cured anywhere on the car repair area because it is lightweight, curing can start immediately with the ON/OFF button because there is no separate preheating time, and it has the advantage of not emitting UV-C wavelengths that are very harmful to the human body.

As an example, an automobile repair film can be formed by performing a step of forming a topcoat film covering the upper portion after forming the above repair film.

Hereinafter, the effects of the present invention will be described with reference to specific synthetic examples, working examples, and experimental results.

[Synthetic example]

Synthesis Example 1. Preparation of UV-curable epoxy acrylate oligomer

In a 2 L glass flask equipped with a temperature controller, a reflux condenser, and a stirring device, 508.2 g of epoxy resin (Kukdo Chemical) YD-128, 191.9 g of acrylic acid, 0.7 g of parabenzoquinone, and 0.21 g of an amine catalyst were placed and the temperature was raised to 110°C to perform a condensation reaction. When the acid value became 10 mg KOH/g or less, heating was stopped and the mixture was cooled to 100°C to obtain a UV-curable epoxy acrylate oligomer (E-1). The resin had a number average molecular weight of 400 to 600, Tg of 4°C, viscosity of 1,000 cps, and solid content of 70%.

Synthesis Example 2. Preparation of UV-curable urethane acrylate oligomer

Using the same device as in Synthetic Example 1, 460.5 g of polyol (PCDL-1000) having a molecular weight of 1,000, 170.4 g of isophorone diisocyanate, 80.1 g of hydroxyethyl acrylate, 0.7 g of parabenzoquinone, and 0.2 g of a tin catalyst were added, the temperature was raised to 75°C to perform a condensation reaction, and heating was stopped when the isocyanate content became 0%, and the mixture was cooled to 70°C to obtain a UV-curable urethane acrylate oligomer (E-2). The resin had a number average molecular weight of 7,000 to 10,000, Tg of 6°C, a viscosity of 20,000 to 30,000 cps, and a solid content of 70%.

<Paint manufacturing>

As shown in Table 1 and Table 2 below, each component was stirred at 1,500 rpm for 30 minutes and then dispersed with a disperser until the particle size became 6NS by Hegman gauge, thereby producing a filler paint for automotive repair.

Characteristics of filling and repair coatings

1) Application of body filler process

#120 The paints of the examples and comparative examples were put into a spray gun (SATA RP 5000, nozzle 1.4 mm) and painted on CR steel plates (cold roll steel) polished with sandpaper at a distance of about 15 to 20 cm under the conditions of air pressure of 1.6 bar, maximum discharge amount, and half of the pattern width, while simultaneously irradiating with a UV LED irradiator (custom-made by Noroo Paint Co., Ltd.) that mainly generates wavelengths between 340 nm and 450 nm to form a coating film of about 2,000 μm. After that, the coating was hardened by irradiation at a distance of 5 cm for 1 minute, and then polished with sandpaper of #180 and dust was removed with compressed air to complete the process before the surfacer was painted.

2) Application of surface process

On the polished body filler film, the paints of the examples and comparative examples were applied at a distance of about 15 to 20 cm with the same spray gun under the conditions of air pressure of 2.0 bar, maximum discharge amount, and maximum pattern width to form a film of about 100 μm, and then the same UV LED irradiator was used for irradiation at a distance of 5 cm for 1 minute to harden, and then the process was completed before the top coat was applied by polishing with #600 sandpaper and degreasing.

3) Apply top coat process

After applying a water-based base coat, Water Q Q-7900 (Noroo Paint Co., Ltd.), on the polished surface film, and drying it with an air blowing gun for about 10 minutes, a clear coat, Hi-Q HC-5300 (Noroo Paint Co., Ltd.), was applied, dried at 60°C for 30 minutes, and left at room temperature for 3 days to produce the final film. Thereafter, the properties of the final film were measured using the following test methods, and the results are shown in Tables 4 and 5.

Characteristic evaluation test method

1) Internal hardening evaluation

The final coating was dug out using a sharp metal spatula or scraper until the substrate was visible, and then the internal hardening was checked by scratching the boundary between the substrate and the final coating with a fingernail or spatula. If there were no particular abnormalities, it was marked as good, and if it was not completely hardened and crumbled or peeled off, it was marked as bad.

2) Adhesion evaluation

After making 100 checkerboard marks at 2 mm intervals on the final coating, cellophane tape was attached and then removed to check the adhesion. At this time, if all 100 checkerboard marks were completely attached, it was evaluated as M-1 (very good), if 70% or more but less than 100% of the remaining checkerboard marks were evaluated as M-2 (good), if 50% or more but less than 70%, it was evaluated as M-3 (average), if 30% or more but less than 50%, it was evaluated as M-4 (bad), and if less than 30%, it was evaluated as M-5 (very bad).

3) Water resistance evaluation

The specimens on which the final coating was formed were immersed in distilled water at 40°C for 240 hours, then taken out and the moisture was wiped off to check for the occurrence of blisters and loss of gloss.

4) Polishing evaluation

The weight of the specimen before and after polishing was measured at the process stage of the body filler and surfacer before the top coat was applied, and the polishing loss due to polishing was calculated. At this time, based on the average polishing loss of 50 g measured with the existing unsaturated polyester paint, 80 to 100 g was marked as very good, 60 to 79 g as good, 40 to 59 g as average, 20 to 39 g as bad, and 19 g or less as very bad.

5) Appearance evaluation of the target

The gloss (Lu), clarity (Sh) and orange peel (Op) of the manufactured final coating were measured using an automobile exterior measuring device, Wave scan dual (BYK Gardner), and the comprehensive appearance evaluation value (Cf) was calculated using the following mathematical formula 1.

[Mathematical Formula 1] Cf = Lu X 0.15 + Sh X 0.35 + Op X 0.5

As shown in Table 3, the coatings manufactured from the compositions of Examples 1 and 2 showed excellent results overall in all items, confirming their suitability as body fillers and surfacers for automobile repair.

On the other hand, as shown in Table 4, Comparative Example 1, which had too low an oligomer content, had poor adhesion and water resistance, and Comparative Example 2, which had too low a photoinitiator content, had poor internal curing properties. In addition, Comparative Example 3, which did not use a UV curing catalyst, showed poor results in overall items such as internal curing properties, adhesion, and water resistance.

The present invention can be used for automobile painting and repairing damaged automobile paint films.

Claims (13)

5 to 35 wt% of UV-curable urethane acrylate oligomer resin formed by addition reaction of 20 to 80 wt% of polyester or polyether polyol, 10 to 40 wt% of diisocyanate, and 10 to 40 wt% of photocurable monomer;
35 to 75 wt% of a polyfunctional acrylate monomer and a monofunctional acrylate monomer;
1 to 10 wt% of photoinitiator;
0.5 to 5 wt% of UV curing accelerator; and
Contains extra pigments,
An automotive refinish filler paint having a viscosity of 50 to 70 KU at 25°C, a specific gravity of 1.10 to 1.50 at 25°C, a particle size of 5 to 7 NS in Hegman gauge, being spray-paintable and applicable to both the body filler process and the surfacer process to form a pore-free automotive refinish film, characterized by excellent adhesion and water resistance, and excellent polishing properties while requiring a short UV irradiation time of less than 1 minute, and being practically usable in automotive refinish sites. An automotive repair filler paint, characterized in that in claim 1, the multifunctional acrylate monomer comprises at least one selected from the group consisting of trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, ethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, trimethylolpropane trioxyethyl(meth)acrylate, tripropylene glycol di(meth)acrylate, and tricyclodecane dimethanol di(meth)acrylate. In the first paragraph, the monofunctional acrylate monomer is diethylaminoethyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, t-octyl (meth)acrylate, N,N-dimethyl (meth)acrylate, N-vinylcaprolactam, N-vinylpyrrolidone, isobutoxy (meth)acrylamide, diacetone (meth)acrylamide, bornyl (meth)acrylate, isobornyl (meth)acrylate, N,N-dimethylacrylamide, ethoxyethoxyethyl (meth)acrylate, methoxyethylene glycol (meth)acrylate, polypropylene glycol mono (meth)acrylate, polyethylene glycol mono (meth)acrylate, phenoxyethyl (meth)acrylate, cyclohexyl (meth)acrylate, Benzyl (meth)acrylate, epoxydiethylene glycol (meth)acrylate, butoxyethyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, styryl (meth)acrylate, octadecyl (meth)acrylate, lauryl (meth)acrylate, dodecyl (meth)acrylate, isodecyl (meth)acrylate, nonyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isoamyl (meth)acrylate, t-butyl (meth)acrylate, isobutyl (meth)acrylate, tricyclodecanyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentadiene (meth)acrylate, methoxypolypropylene glycol (meth)acrylate, An automotive refinish filler paint characterized in that it comprises at least one selected from the group consisting of methoxypolyethylene glycol (meth)acrylate, butyl (meth)acrylate, isopropyl (meth)acrylate, propyl (meth)acrylate, ethyl (meth)acrylate, and methyl (meth)acrylate. An automotive repair filler paint, characterized in that in claim 1, the photocurable monomer comprises at least one selected from the group consisting of 2-hydroxyethyl acrylate, pentaerythritol tri(meth)acrylate, 4-hydroxybutyl acrylate, hydroxypropyl acrylate, 2-hydroxypropyl(meth)acrylate, and 2-hydroxyethyl(meth)acrylate. In claim 1, in claim 1, the diisocyanate is isophorone diisocyanate, 2,4-toluene diisocyanate and isomers thereof, hexamethylene diisocyanate, 2,2-bis-4'-propane diisocyanate, m-phenylene diisocyanate, 1,5-naphthalene diisocyanate, 1,4-xylene diisocyanate, 1,3-xylene diisocyanate, isophorone diisocyanate, 1,5-naphthalene diisocyanate, 6-isopropyl-1,3-phenyl diisocyanate, 1,6-hexanediisocyanate, 4,4'-biphenylene diisocyanate, 3,3'dimethylphenylene diisocyanate, 3,3'-dimethyl-4,4'-diphenylmethane diisocyanate, p-phenylene A filler paint for automotive refinishing, characterized in that it comprises at least one selected from the group consisting of diisocyanate, 1,4-xylene diisocyanate and 1,3-xylene diisocyanate. An automotive repair filler paint, characterized in that in claim 1, the UV curing accelerator comprises at least one of 3-mercaptopropionate and an amine synergist. delete 5 to 35 wt% of UV-curable epoxy acrylate oligomer resin formed by esterifying 50 to 80 wt% of epoxy resin, 20 to 50 wt% of acrylic acid or methacrylic acid, and 0.05 to 0.2 wt% of polymerization inhibitor;
35 to 75 wt% of a polyfunctional acrylate monomer and a monofunctional acrylate monomer;
1 to 10 wt% of photoinitiator;
0.5 to 5 wt% of UV curing accelerator; and
Contains extra pigments,
An automotive refinish filler paint having a viscosity of 50 to 70 KU at 25°C, a specific gravity of 1.10 to 1.50 at 25°C, a particle size of 5 to 7 NS in Hegman gauge, being spray-paintable and applicable to both the body filler process and the surfacer process to form a pore-free automotive refinish film, characterized by excellent adhesion and water resistance, and excellent polishing properties while requiring a short UV irradiation time of less than 1 minute, and being practically usable in automotive refinish sites. A step of forming a repair film by spraying the car repair filler paint of claim 1 onto the surface of an object on which a car repair film is to be formed and irradiating ultraviolet rays at the same time; and
An automobile repair method comprising a step of polishing a surface of an object on which a repair film has been formed. A method for repairing an automobile, characterized in that in claim 9, the repair film is formed to a thickness of 1,500 to 2,000 μm and the repair film does not contain pores. In claim 9, an automobile repair method characterized in that the ultraviolet irradiation uses an ultraviolet generator that mainly generates ultraviolet rays with a wavelength in the range of 340 nm to 450 nm. An automobile repair method, characterized in that in claim 9, further comprising a step of forming a topcoat covering the repair film. A step of forming a repair film by spraying the car repair filler paint of claim 8 onto the surface of an object on which a car repair film is to be formed and irradiating ultraviolet rays at the same time; and
An automobile repair method comprising a step of polishing a surface of an object on which a repair film has been formed.