KR20070017278A - Photo-curable coating composition, method for preparing the same and product prepared by the same - Google Patents

Abstract

A photocurable coating composition is provided.

The photocurable coating composition according to the present invention contains 200 to 800 parts by weight of methyl methacrylate and trimethylol propane triacrylate or dipentaerythritol penta / hexa acrylate mixture based on 100 parts by weight of urethane acrylate hyperbranched prepolymer. To 150 parts by weight; And 10 to 30 parts by weight of a photoinitiator, which is not subject to environmental regulations because it does not use an organic solvent, and can be coated by spray because of its low viscosity, and thus excellent work efficiency, heat resistance, Because of its excellent wear resistance, scratch resistance, chemical resistance and yellowing resistance, it can be widely used as a coating material for various substrates.

Photocurable coating composition,

Description

Photo-curable coating composition, manufacturing method and product manufactured using same {Photo-curable coating composition, method for preparing the same and product prepared by the same}

1 is an infrared spectroscopy graph of the urethane acrylate hyperbranched prepolymer used in the present invention.

2 is a weight analysis graph according to Example 1.

The present invention relates to a photocurable coating composition, and more particularly, by further reacting a urethane acrylate hyperbranched prepolymer having a high adhesive property with an acrylate having excellent physical properties, further improving the physical properties of the film and requiring no solvent. The present invention relates to a photocurable coating composition having improved workability, a method of manufacturing the same, and a product manufactured using the same.

The surface of plastic molded products such as polycarbonate, polystyrene, styrene-acrylonitrile, polyester, acrylonitrile-butadiene-styrene, etc. has a disadvantage in that it is weaker than glass or metal products in wear resistance, scratch resistance, solvent resistance, and the like. Accordingly, in order to remedy such disadvantages, a method of applying a silicone resin or melamine resin to the surface of the plastic, and a method of forming a protective film of metal texture by aluminum vacuum deposition have been used. However, the silicone resin and the like should be exposed to heat for a long time in order to form a coating film as a thermosetting paint. As such, productivity may be lowered due to prolonged heating, and high temperatures may adversely affect the physical properties of the plastic substrate. have. In addition, in the case of the aluminum vacuum deposition, there is a problem in the adhesion between the paint and aluminum, there is a fear that the deposited film is easily peeled off during use.

Accordingly, in order to solve this problem, a method of forming a coating film by coating a substrate in which a polyurethane is dissolved in an organic solvent on a substrate and evaporating the solvent has been developed. Such a urethane coating has low adhesiveness and strength, and a volatile organic material ( VOC (volatile organic compounds) Due to the problem of air pollution due to evaporation, its use is increasingly restricted. Currently, regulations on VOCs, all organic volatiles including organic solvents, are accelerating around the world, and the CAA (Clean Air) from Rule66 (1966) in California and EPA (1977) for the prevention of optical smog in the United States. Act: Air Purification Act was enacted, and RACT (Reasonably Available Control Technology) came into force as a guideline of VOC, and in 1990, HAPS (Hazardous Air Pollutants), a comprehensive reassessment of CAA, was enacted and Classified by to regulate emissions and concentrations. Therefore, the situation is gradually tightening the restrictions and restrictions on the application of the coating liquid that should use such an organic solvent.

On the other hand, the Republic of Korea Patent Publication No. 93-13,027 discloses an ultraviolet curable coating film composition for the vinyl chloride sheet, but since the composition further comprises a non-reactive oligomer is a thermoplastic acrylic resin, the viscosity is 300 ~ 5,000CPS at 25 ℃ Too high, poor workability due to the inability to use spray coating methods, and not only sufficient mechanical properties such as heat resistance, abrasion resistance, scratch resistance and flexibility to use as coatings for a wide range of plastic molded articles, but also aromatic diisocyanates In this case, there is a problem in that yellowing occurs due to quinone imide structure caused by ultraviolet rays.

 In addition, Korean Patent No. 139,881 discloses a form in which an aliphatic polyfunctional isocyanate containing an isocyanurate ring of hexamethylene diisocyanate and hydroxy alkyl (meth) acrylate and caprolactone modified hydroxy ethyl acrylate are reacted. A photocurable resin composition composed of a prepolymer, a reactive diluent, a photoinitiator and other additives is disclosed. However, the above-mentioned air pollution problems occur because the spray coating method cannot be used due to the high viscosity and the organic solvent must be used. As a result, process efficiency is reduced. In addition, there is a disadvantage in that the adhesive and the coating film easily fall off because the adhesion to the adherend is poor, there is still a problem that the mechanical properties such as heat resistance, wear resistance, scratch resistance and flexibility are not enough.

Therefore, the first technical problem to be achieved by the present invention is to overcome the problems of the prior art, spray viscosity is possible even in the absence of solvent type, excellent adhesion to the adhesive, wear resistance, chemical resistance and scratch resistance and Since there is little concern about yellowing, it is to provide a photocurable coating composition that can be used for various substrates including general purpose plastics.

The second technical problem to be achieved by the present invention is to provide a method for producing the photocurable coating composition.

The third technical problem to be achieved by the present invention is to provide a product manufactured using the photocurable coating composition.

The present invention to achieve the first technical problem,

The hydroxyl group of the polycaprolactone triol and one isocyanate group of isophorone diisocyanate form a urethane bond, and the other isocyanate group is another polycaprolactone triol, hydroxyethyl (meth) acrylate or hydroxypropyl (meth) acrylate. Urethane acrylate hyperbranched prepolymer, characterized in that by forming a hydroxyl group and a urethane bond, the repeating unit of the formula (1) radially bonded in the molecule;

Wherein R ₁ is hydrogen or methyl;

R ₂ is ethylene or propylene;

X is a residue excluding hydrogen of the hydroxy group in polycaprolactone triol, hydroxyethyl (meth) acrylate or hydroxypropyl (meth) acrylate, and at least one of the three X's is a hydroxyl group in the polycaprolactone triol Residues other than hydrogen;

n is an integer of 1 to 5)

Methylmethacrylate (MMA); Trimethylol propane triacrylate (TMPTA), dipentaerythritol penta / hexa acrylate (DPHA) or mixtures thereof; And it provides a photocurable coating composition comprising a photoinitiator.

According to one embodiment of the invention, the photocurable coating composition according to the present invention 200 to 800 parts by weight of methyl methacrylate based on 100 parts by weight of the urethane acrylate hyperbranched prepolymer; 80 to 150 parts by weight of trimethylol propane triacrylate or dipentaerythritol penta / hexa acrylate mixture; And 10 to 30 parts by weight of the photopolymerization initiator.

 According to another embodiment of the present invention, the weight average molecular weight of the polycaprolactone triol (PCLT) used in the urethane acrylate hyperbranched prepolymer may be 300 to 900.

According to another embodiment of the present invention, the weight average molecular weight of the urethane acrylate hyperbranched prepolymer is preferably 1,000 to 4,000, and the viscosity at room temperature of the photocurable coating composition is preferably 1.10 cP or less.

The present invention to achieve the second technical problem,

(a) reacting a polycaprolactone triol having a weight average molecular weight of 300 to 900 with an isophorone diisocynate (IPDI) compound;

(b) preparing a urethane acrylate hyperbranched prepolymer by adding and reacting hydroxyethyl (meth) acrylate or hydroxypropyl (meth) acrylate to the urethane oligomer obtained above; And

(c) the urethane acrylate hyperbranched prepolymer obtained above; 200 to 800 parts by weight of methyl methacrylate based on 100 parts by weight of the prepolymer; 80 to 150 parts by weight of trimethylol propane triacrylate, dipentaerythritol penta / hexa acrylate or mixtures thereof; And it provides a photocurable coating composition comprising the step of mixing 10 to 30 parts by weight of the photopolymerization initiator.

According to one embodiment of the present invention, the amount of isophorone diisocyanate used in step (a) is 2 to 3 moles based on 1 mole of polycaprolactone triol, and hydroxyethyl ( The amount of meta) acrylate or hydroxypropyl (meth) acrylate may be 3 to 3.5 moles based on 1 mole of polycaprolactone triol.

The present invention provides a product prepared by coating the photocurable coating composition according to the invention on the surface of the product, and then cured with ultraviolet rays in order to achieve the third technical problem.

According to one embodiment of the present invention, the hardness of the coating film formed by curing the coating composition is preferably 6-9H.

Hereinafter, the present invention will be described in more detail.

The photocurable coating composition according to the present invention is excellent in heat resistance, abrasion resistance, scratch resistance and adhesiveness with the adherend, and there is no fear of yellowing and the viscosity is low, so that it can be coated by spraying without using an organic solvent. It is characterized by excellent efficiency.

 The hyperbranched structure prepolymer refers to a polymer in which a predetermined unit structure of a tree branch is repeatedly extended from the core, and in the present invention, the prepolymer is crosslinked before photocuring by using the hyperbranched structure prepolymer. It is possible to improve the mechanical properties of the final coating film by improving the crosslinking density.

The heat resistance of the photocurable coating composition is due to the properties of the polyols and diisocyanates used in the present invention. That is, in the case of the polycaprolactone triol used in the urethane acrylate prepolymer according to the present invention, unlike polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, or polycarbonate diol, etc., which are used to prepare a urethane acrylate prepolymer, There is almost no change in physical properties with temperature, and there is no heat generation or endotherm during curing, so there is no heat stress or heat shock. In addition, since isophorone diisocyanate used in the present invention has excellent heat resistance and excellent yellowing resistance, it is possible to improve the heat resistance and yellowing resistance of the final coating composition. Specifically, in the case of using isophorone diisocyanate, unlike the case of using an aromatic diisocyanate compound, there is no possibility of changing to a quinone imide structure by ultraviolet rays, and thus no ultraviolet absorber or antioxidant is added separately. Yellowing can be prevented. In addition, cycloaliphatic diisocyanates such as isophorone diisocyanate also have the advantage of exhibiting excellent properties in toughness and impact resistance.

In addition, the wear and scratch resistance of the photocurable coating composition according to the invention is due to the properties of the prepolymers having acrylate and hyperbranched structures used in the coating composition. That is, the more functional groups of the acrylate used, the higher the hardness and the improved mechanical properties. In the present invention, trifunctional trimethylol propane triacrylate, 5 or 6 functional dipentaerythritol penta / hexa acrylate or Since a mixture of these is used, the degree of crosslinking of the final coating film is high and thus the hardness is high. However, when the hardness is too high, the brittleness becomes large, and the viscosity of the composition before curing is too high to be suitable for use as a solvent-free spray coating, and to compensate for this, methyl methacrylate having excellent flexibility and elasticity is used together. . The most preferred embodiment is the case of using a mixture of trimethylol propane triacrylate and dipentaerythritol penta / hexa acrylate, which may have both optimum hardness and flexibility. On the other hand, as already described, the cross-linking density is increased due to the cross-linked form of the hyper-branched structure, thereby improving wear resistance and scratch resistance.

The polycaprolactone triol used as the polyol in the present invention has a characteristic of being able to improve adhesion to the adherend because of its high hydrophilicity due to its large number of carbonyl groups and excellent adhesion and flexibility. In addition, since the hydrophobic and hydrophilic units are present in the polycaprolactone triol, it is also advantageous that the final coating composition is easily blended with other polymers.

The photocurable coating composition according to the present invention comprises 200 to 800 parts by weight of methyl methacrylate based on 100 parts by weight of the urethane acrylate hyperbranched prepolymer; 80 to 150 parts by weight of trimethylol propane triacrylate, dipentaerythritol penta / hexa acrylate or mixtures thereof; And 10 to 30 parts by weight of the photopolymerization initiator, and in the case of the above component ratios, while having an appropriate viscosity for spray coating, mechanical properties such as adhesion, flexibility and wear resistance can be optimally controlled. .

Methyl methacrylate used in the present invention, as already described, serves to give flexibility and elasticity to the final coating film, and at the same time serves to adjust the viscosity by diluting the final coating composition, spraying using a spray or the like Allow coating. Based on 100 parts by weight of the urethane acrylate hyperbranched prepolymer, when the content of the methyl methacrylate is less than 200 parts by weight, the viscosity is too high, so it is not suitable for spray coating, when the hardness of the final coating film exceeds 800 parts by weight. There is a risk of falling.

In addition, when the amount of the trimethylol propane triacrylate, dipentaerythritol penta / hexa acrylate or a mixture thereof is less than 80 parts by weight, the hardness of the final coating film is lowered, and when it exceeds 150 parts by weight, the flexibility of the final coating film may be inferior. There is concern.

It is preferable that the weight average molecular weight of the polycaprolactone triol used in the present invention is 300 to 900. When the weight average molecular weight is less than 300, the hardness is too high. When the coating composition is cured, it is not preferable because the hardness is so low that the coating film may be radiant.

When the polycaprolactone triol is used according to the present invention, since the urethane acrylate hyperbranched prepolymer itself has a branched radial structure and is a network structure from the beginning, it is possible to further improve the crosslinking density of the final coating layer during UV curing. As a result, mechanical properties such as wear resistance can be further improved.

The weight average molecular weight of the urethane acrylate hyperbranched prepolymer according to the present invention is preferably 1,000 to 4,000. When the weight average molecular weight is less than 1,000, the hardness may be too high. When the weight average molecular weight is more than 4,000, the viscosity becomes high and the final coating. It is not preferable because the hardness of the composition is too low when the composition is cured so that the coating film may be radiant.

The viscosity at room temperature of the photocurable coating composition is preferably 1.10 cP or less. If the viscosity exceeds 1.10 cP, it is not suitable for spray coating using a spray.

On the other hand, before the addition of hydroxyethyl (meth) acrylate or hydroxypropyl (meth) acrylate in the preparation of the urethane acrylate hyperbranched prepolymer, by adding 2,2'-bis (hydroxymethyl) propionic acid Properties and adhesiveness can be further improved. The 2,2'-bis (hydroxymethyl) propionic acid further improves adhesion to the adherend due to the presence of a carboxyl group, and serves as a chain extender, and thus increases the mechanical strength since the chain length is increased. Can be.

The method for preparing a photocurable coating composition according to the present invention comprises the steps of: (a) reacting a polycaprolactone triol having a weight average molecular weight of 300 to 900 with an isophorone diisocyanate compound; (b) preparing a urethane acrylate hyperbranched prepolymer by adding and reacting hydroxyethyl (meth) acrylate or hydroxypropyl (meth) acrylate to the urethane oligomer obtained above; And (c) the urethane acrylate hyperbranched prepolymer obtained above; 200 to 800 parts by weight of methyl methacrylate based on 100 parts by weight of the prepolymer; 80 to 150 parts by weight of trimethylol propane triacrylate, dipentaerythritol penta / hexa acrylate or mixtures thereof; And mixing 10 to 30 parts by weight of the photopolymerization initiator.

The amount of isophorone diisocyanate used in step (a) is 2 to 3 moles based on 1 mole of polycaprolactone triol, and hydroxyethyl (meth) acrylate or hydroxypropyl used in step (b). The amount of (meth) acrylate may be 3 to 3.5 moles based on 1 mole of polycaprolactone triol. When the amount of isophorone diisocyanate is less than 2 moles, the formation of the hyperbranched prepolymer is not good, and 3 moles are used. When exceeding, the isocyanate group of the isophorone diisocyanate is reacted with the hydroxyl group of hydroxyethyl (meth) acrylate or hydroxypropyl (meth) acrylate which is added later, instead of the hydroxy group of the polycaprolactone triol, to thereby It is not preferable because it may remain as an impurity by side reaction. not. On the other hand, the amount of the hydroxyethyl (meth) acrylate or hydroxypropyl (meth) acrylate is less than 3 mol When the end capping for the isocyanate group is not properly done, there is a concern that the unreacted isocyanate group remains, and when it exceeds 3.5 moles, it is excessively necessary so that it is in the sock end of the isophorone diisocyanate that does not react. There is a fear that side reactions that react with both isocyanate groups occur or remain unreacted in the prepolymer of the hyperbranched structure.

Meanwhile, in step (a), the reaction temperature is about 80 ° C. to 100 ° C. and the reaction time is about 3 hours, and a catalyst such as dibutyl dilaurate may be used for the reaction activity. In addition, the reaction temperature in step (b) is about 50 ℃ to 70 ℃ and the reaction time is about 3 hours, all the reaction is carried out under a nitrogen atmosphere.

The product manufactured using the photocurable coating composition according to the present invention is characterized in that the photocurable coating composition is spray-coated onto a substrate using a spray, and then cured by irradiating ultraviolet rays. The spraying method is not particularly limited, and a spray gun having an injection hole of 3 mm using a 3/4 horsepower pump may be used.

It is preferable that the hardness of the coating film formed by curing the coating composition according to the present invention is 5 to 9H. If it is less than 5H, scratch resistance and abrasion resistance are not sufficient, and when it exceeds 9H, brittleness becomes too large and the coating film may be broken. .

On the other hand, the photopolymerization initiator that can be used in the present invention is not particularly limited as long as it is commonly used in the art, for example, hydroxy cyclohexylphenyl ketone, 2,2-dimethoxy-2-phenyl, aceto Petone, benzophenone, phenyl-2-hydroxy 2-propyl ketone and the like can be used. The amount of the photopolymerization initiator may be 10 to 30 parts by weight based on 100 parts by weight of the urethane acrylate hyperbranched prepolymer. When it is less than 30 parts by weight, the polymerization rate is slow, and when the amount exceeds 30 parts by weight, the physical properties of the coating film are deteriorated. Can be.

The photocurable coating composition according to the present invention may further comprise conventional additives such as pigments, stabilizers, surfactants, fillers such as micro-unit metal particles, UV-absorbers and the like.

Hereinafter, the present invention will be described in more detail with reference to preferred examples, but the present invention is not limited to the following examples.

Example 1

1- (1). Preparation of Radial Urethane Acrylate Hyperbranched Prepolymer

Into the flask, 0.01 mol of polycaprolactone triol having a weight average molecular weight of 900 (Aldrich) and 0.025 mol of isophorone diisocyanate (manufactured by Aldrich) were set at an oil bath temperature of 80 ° C. for 1 hour. Mixed during. Next, the solution was cooled to 60 ° C., and then 0.03 mol of hydroxyethyl methacrylate was added and reacted for 1 hour, followed by adding 1-2 drops of dibutyltin dilaurate as a catalyst. The reaction was carried out for 1 hour to obtain a radial urethane acrylate hyperbranched prepolymer having a weight average molecular weight of 3,000.

FT-IR: 3000 cm ^-1 (NH stretching), 1720cm ^-1 (C = O stretching), 1530cm ^-1 (C-NH stretching in urethane)

1 shows an infrared spectroscopy graph for the radial urethane acrylate hyperbranched prepolymer. Referring to this, it can be seen that all of the isocyanates participated in the reaction because there was no peak around about 2270 cm ^-1 .

Preparation of 1- (2) Photocurable Coating Composition

10 g of the above-mentioned radial urethane acrylate hyperbranched prepolymer was put in an Erlenmeyer flask, and then 30 g of methyl methacrylate (manufactured by Aldrich) and 10 g of trimethylol propane triacrylate (manufactured by Aldrich) were added thereto at 60 ° C. Mix for 60 minutes at temperature. Finally, hexyl phenyl ketone (1-hydroxy cyclohexyl phenyl ketone) was added at 3% by weight of the total weight to prepare a photocurable coating composition.

Example 2

In the same manner as in Example 1, except that 10 g of the radial urethane acrylate hyperbranched prepolymer obtained in Example 1- (1) was reacted with 50 g of methyl methacrylate and 10 g of dipentaerythritol penta / hexa acrylate. Photocurable coating compositions were prepared.

Example 3

Before adding hydroxyethyl methacrylate in Example 1- (1), 0.2 g of 2,2'-bis (hydroxymethyl) propionic acid was added and reacted for 1 hour to improve mechanical properties and adhesion. After adding 0.03mol of hydroxyethyl methacrylate, the mixture was further reacted for 1 hour. 10 g of the radial urethane acrylate hyperbranched prepolymer obtained above and 30 g of methyl methacrylate were mixed, and 10 g of trimethylol propane triacrylate was added and mixed at a temperature of 60 ° C. for 60 minutes. Finally, hexyl phenyl ketone (1-hydroxy cyclohexyl phenyl ketone) was added at 3% by weight of the total weight to prepare a photocurable coating composition.

Example 4

10 g of the radial urethane acrylate hyperbranched prepolymer obtained in Example 3, 50 g of methyl methacrylate, 5 g of trimethylol propane triacrylate, and 5 g of dipentaerythritol penta / hexa acrylate were reacted. Photocurable coating compositions were prepared in the same manner as in Example 3.

Comparative Example 1

0.3 mole of polyester polyol produced by condensation of adipic acid and neopentyl glycol to 1 mole of 2,4-toluene diisocyanate, 0.2 mole of polytetrahydrofuran (weight average molecular weight 650), and 1 mole of 2-hydroxyethyl acrylate 40 parts of urethane acrylates prepared by reacting; 10 parts of a non-reactive oligomer prepared by reacting 620 parts of methyl methacrylate, 7 parts of methyl acrylate, 50 parts of butyl acrylate and 100 parts of polypropylene glycol monoacrylate with a benzyl peroxide catalyst in the presence of methyl isobutyl ketone; 10 parts of 1,6-hexanediol diacrylate, 10 parts of 2-ethylhexyl acrylate, 25 parts of N-vinyl-2-pyrrolidone, 2.5 parts of benzophenone, 2 parts of hydroxycyclohexyl phenyl ketone, silicone poly 0.5 parts of acrylate (UCC Ebecryl 360) was stirred at 40 ° C. to prepare a photocurable coating composition.

Test Example 1

Measurement of Viscosity of Coating Composition

The viscosity of the coating composition prepared in Examples 1 to 4 and Comparative Example 1 was measured at 20 ℃ using the Ostwald viscometer, the results are shown in Table 1 below.

air water Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Viscosity 0.018cP 1cP 1.03cP 1.02cP 1.04cP 1.03cP 800 cP

Test Example 2

Heat resistance test

The coating composition prepared in Example 1 was applied on an ABS plate with a spray gun having a spray hole of 3 mm using a 3/4 hp pump, and irradiated for about 10 seconds at 1400 mJ / cm ² and an irradiation distance of 15 cm using a mercury UV curing machine. After photocuring by the thermogravimetric analysis, the results are shown in FIG. 2. Referring to this, it can be seen that the thermal stability of the coating composition according to the present invention is excellent because the temperature at which the weight is drastically reduced is 300 ° C. or more.

Test Example 3

Abrasion Resistance Test

The coating composition prepared in Examples 1 to 4 was applied onto a polycarbonate plate using a spray gun having a spray hole of 3 mm using a 3/4 horsepower pump, and the coating composition of Comparative Example 1 was applied by a doctorblet coating method. Next, using a mercury UV curing machine was irradiated for about 10 seconds at 1400mJ / cm ² , the irradiation distance 15cm for photocuring. Next, using an RCA abrasion tester (manufactured by Norman Tool), a load of 275 g was applied to the wide paper (Tokyo Hi Max 11 / 16inch x 33 cm) and bitten by the coating surface of the sample at a speed of 33 times / min. 50 operations were performed. As a result, it was determined as pass when the moser of the coated surface was not exposed, and failed when the moser was exposed, and the results are shown in Table 2 below.

Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Wear resistance pass pass pass pass fail

Test Example 4

Hardness test ( Scratch resistance  Test)

The coating composition prepared in Examples 1 to 4 was applied onto a polycarbonate plate using a spray gun having a spray hole of 3 mm using a 3/4 horsepower pump, and the coating composition of Comparative Example 1 was applied by a doctorblet coating method. Next, using a mercury UV curing machine was irradiated for about 10 seconds at 1400mJ / cm ² , the irradiation distance 15cm for photocuring. Next, by cutting only the wood part of the pencil (Mitsubishi pencil Co., Ltd.) and exposing the core to a cylindrical shape about 3 mm, the core is placed at a right angle on a flat surface and polished while drawing a circle to polish the end of the shim. After the sharpening, the pencil lead is brought into contact with the coating surface at an angle of about 45 °, and then the hardness measuring instrument (manufactured by Sunhayato, ASTM D5178) is set to be parallel to the coating surface, and then the front of the measuring instrument is It was to move about 10mm, and changed the position of the sample was tested five times each, and the hardness of the pencil that was scratched at least once of five times was expressed as the hardness of the coating surface, the results are shown in Table 3 below.

Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Pencil hardness 6H 6H 7H 7H 3H

Test Example 5

Chemical resistance test

The coating composition prepared in Examples 1 to 4 was applied onto a polycarbonate plate using a spray gun having a spray hole of 3 mm using a 3/4 horsepower pump, and the coating composition of Comparative Example 1 was applied by a doctorblet coating method. Next, using a mercury UV curing machine was irradiated for about 10 seconds at 1400mJ / cm ² , the irradiation distance 15cm for photocuring. Next, the industrial pencil eraser was fixed to a print life tester (KR-RCA-001, manufactured by Koryo QMS Co., Ltd.) and contacted on the coating surface while applying a load of 500 g to the eraser, followed by methanol (99.8%). It was confirmed that the coating film was peeled off by adding 250 times at a rate of 40 round trips / min while the coating film was not dried, and the number of the coating films peeled off by using 10 coated plates each is shown in Table 4 below.

Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Chemical resistance 0 0 0 0 3

Test Example 6

Yellowing  Test

The coating composition prepared in Examples 1 to 4 was applied onto a polycarbonate plate using a 3/4 horsepower pump with a spray gun having a spray hole of 3 mm, and the coating composition of Comparative Example 1 was applied by a doctorblet coating method. . The coated surface was irradiated with ultraviolet light for 10 minutes using an ultraviolet lamp, and then left for 24 hours in a thermo-hygrostat under 100 ° C. 80% humidity condition, and then yellowing before and after the test was visually determined. The number of yellowing occurred by using each of 10 is shown in Table 5 below.

Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Yellowing 0 0 0 0 10

Test Example 7

Cross-cutting test

The coating composition prepared in Examples 1 to 4 was applied onto a polycarbonate plate using a spray gun having a spray hole of 3 mm using a 3/4 horsepower pump, and the coating composition of Comparative Example 1 was applied by a doctorblet coating method. Next, using a mercury UV curing machine was irradiated for about 10 seconds at 1400mJ / cm ² , the irradiation distance 15cm for photocuring. Next, draw a line with a cutting knife to reach the substrate surface at 1 mm intervals on the coated specimen, and then form an eye shape. Then, the OPP adhesive tape is adhered and pulled strongly in the vertical direction to visually check whether the coating surface is peeled off. Determined. When the checkerboard is not peeled off at all,?, When 2/3 or more remains, △, when less than 2/3 remain X and the results are shown in Table 6 below.

Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Adhesion ○ ○ ○ ○ X

Referring to Table 6, it can be seen that the coating composition according to the present invention has excellent adhesion to the adherend.

As described above, the photocurable coating composition according to the present invention is not subject to environmental regulations because it does not use an organic solvent, and can be coated by spray because of its low viscosity. Because of its excellent wear resistance, scratch resistance, chemical resistance and yellowing resistance, it can be widely used as a transparent coating material for various substrates such as mobile phones.

Claims (9)

The hydroxyl group of the polycaprolactone triol and one isocyanate group of isophorone diisocyanate form a urethane bond, and the other isocyanate group is another polycaprolactone triol, hydroxyethyl (meth) acrylate or hydroxypropyl (meth) acrylate. A urethane acrylate hyperbranched prepolymer, wherein a repeating unit of the following formula (1) is radially bonded in a molecule by forming a urethane bond with a hydroxyl group of;

(One) Wherein R ₁ is hydrogen or methyl; R ₂ is ethylene or propylene; X is a residue excluding hydrogen of the hydroxy group in polycaprolactone triol, hydroxyethyl (meth) acrylate or hydroxypropyl (meth) acrylate, and at least one of the three X's is a hydroxyl group in the polycaprolactone triol Residues other than hydrogen; n is an integer of 1 to 5) Methyl methacrylate; Trimethylol propane triacrylate or dipentaerythritol penta / hexa acrylate mixture; And Photocurable coating composition comprising a photoinitiator. According to claim 1, 200 to 800 parts by weight of methyl methacrylate based on 100 parts by weight of the urethane acrylate hyperbranched prepolymer; 80 to 150 parts by weight of trimethylol propane triacrylate or dipentaerythritol penta / hexa acrylate mixture; And A photocurable coating composition comprising 10 to 30 parts by weight of a photopolymerization initiator. The photocurable coating composition according to claim 1, wherein the polycaprolactone triol has a weight average molecular weight of 300 to 900. The photocurable coating composition according to claim 1, wherein the urethane acrylate hyperbranched prepolymer has a weight average molecular weight of 1,000 to 4,000, and a viscosity at room temperature of the photocurable coating composition is 1.10 cP or less. (a) reacting a polycaprolactone triol having a weight average molecular weight of 300 to 900 with isophorone diisocyanate; (b) preparing a urethane acrylate hyperbranched prepolymer by adding and reacting hydroxyethyl (meth) acrylate or hydroxypropyl (meth) acrylate to the urethane oligomer obtained above; And (c) the urethane acrylate hyperbranched prepolymer obtained above; 200 to 800 parts by weight of methyl methacrylate based on 100 parts by weight of the prepolymer; 80 to 150 parts by weight of trimethylol propane triacrylate, dipentaerythritol penta / hexa acrylate or mixtures thereof; And 10 to 30 parts by weight of the photopolymerization initiator. The amount of isophorone diisocyanate used in step (a) is 2 to 3 moles based on 1 mole of polycaprolactone triol, and hydroxyethyl (meth) used in step (b). A method of producing a photocurable coating composition, characterized in that the amount of acrylate or hydroxypropyl (meth) acrylate is 3 to 3.5 moles based on 1 mole of polycaprolactone triol. The method of claim 5, further comprising adding 2,2'-bis (hydroxymethyl) propionic acid before step (b). An article prepared by applying the coating composition according to any one of claims 1 to 4 on the surface of the article and then curing with ultraviolet rays. The product of claim 8, wherein the coating composition is cured to have a hardness of 5 to 9H.

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