UV-curable paint composition

Abstract

The present invention provides a UV-curable paint composition comprising a bio-based urethane (meth)acrylate resin, a (meth)acrylate monomer, and a photoinitiator, wherein the bio-based urethane (meth)acrylate resin comprises a first bio-based urethane (meth)acrylate resin and a second bio-based urethane (meth)acrylate resin. The UV-curable paint composition is environmentally friendly and can minimize the discharge of carbon dioxide.

Description

UV-curable paint composition

[0001] The present invention relates to an environmentally friendly ultraviolet curable paint composition.

[0002]

[0003] UV-curable coating compositions are widely used as coatings to protect the surfaces of various materials, such as buildings, ships, bridges, and automobiles. Coatings formed from these UV-curable coating compositions require various physical properties, such as excellent appearance characteristics, scratch resistance, adhesion, impact resistance, and moisture resistance. Active research is being conducted to improve the physical properties of UV-curable coating compositions. For example, Korean Patent No. 10-1035822 discloses a photocurable coating for a hard coating material for plastics, comprising urethane acrylate, an acrylate compound, and a photoinitiator, but excluding an acrylate compound having an aromatic ring structure.

[0004] However, conventional UV-curable paint compositions are manufactured using resins, monomers, and solvents derived from fossil fuels like petroleum and coal. The manufacturing process inevitably produces carbon dioxide, a contributor to global warming. Therefore, there is a need to develop environmentally friendly UV-curable paint compositions that can minimize carbon dioxide emissions.

[0005]

[0006] The present invention provides an environmentally friendly ultraviolet-curable paint composition capable of minimizing carbon dioxide emissions.

[0007]

[0008] The present invention provides an ultraviolet curable paint composition comprising a bio-based urethane (meth)acrylate resin, a (meth)acrylate monomer, and a photoinitiator.

[0009]

[0010] The present invention provides an environmentally friendly UV-curable paint composition capable of minimizing carbon dioxide emissions. The UV-curable paint composition according to the present invention is environmentally friendly and offers excellent paintability, appearance, moisture resistance, and other physical properties. The UV-curable paint composition of the present invention has a high bio-content, making it applicable to various industrial fields requiring high bio-content. For example, the UV-curable paint composition of the present invention can be used as a paint for automotive interiors subject to strict environmental standards.

[0011]

[0012] Figure 1 illustrates a scratcher used for evaluating scratch resistance.

[0013] Figure 2 shows the evaluation criteria for chemical resistance.

[0014] Figure 3 illustrates a reciprocating wear tester used for evaluating wear resistance.

[0015]

[0016] The present invention will be described in detail below. However, it is not limited to the following description, and each component may be modified or selectively mixed as needed. Therefore, it should be understood that all modifications, equivalents, and alternatives included within the spirit and technical scope of the present invention are included.

[0017] The “weight average molecular weight” used herein is measured by a conventional method known in the art, and can be measured, for example, by the GPC (gel permeation chromatography) method. The “viscosity” is measured by a conventional method known in the art, and can be measured, for example, using a Brookfield viscometer at room temperature (25°C). Functional values ​​such as “acid value” or “hydroxyl value” are measured by a conventional method known in the art, and can be measured, for example, by the titration method.

[0018] The UV-curable coating composition according to the present invention provides a UV-curable coating composition comprising a bio-based urethane (meth)acrylate resin, a (meth)acrylate monomer, and a photoinitiator. The coating composition according to the present invention may further include additives commonly used in the field of UV-curable coatings, such as a solvent, an adhesion promoter, an ultraviolet absorber, a dispersant, a catalyst, a surface conditioner, a polymerization inhibitor, and a matting agent, as needed.

[0019] The UV-curable coating composition of the present invention uses a bio-based urethane (meth)acrylate resin, which is a biomass raw material. Since the sum of carbon dioxide emissions and absorption during the life cycle of biomass raw materials is zero, it does not increase the amount of carbon dioxide.

[0020] The biocontent (based on solid content) of the UV-curable coating composition of the present invention is 15 wt% or more, for example, 15 to 40 wt%, or another example, 15 to 30 wt%. The UV-curable coating composition of the present invention is environmentally friendly due to its high biocontent, and can be applied to various industrial fields requiring a high biocontent. The biocontent is measured by a radiocarbon analysis technique according to ASTM-D6866-12 (% BiobasedCarbon Content). Biomass materials contain radiocarbon (C14), an isotope of carbon, whereas petrochemical-derived materials do not contain C14. Therefore, the biocontent can be calculated by calculating the content of C14 in the total carbon content.

[0021]

[0022] Bio-based urethane (meth)acrylate resin

[0023] The ultraviolet-curable coating composition of the present invention comprises a urethane (meth)acrylate resin. The urethane (meth)acrylate resin is a main component of the dry coating film and serves to provide basic properties such as adhesion, scratch resistance, and iodine resistance.

[0024] The above urethane (meth)acrylate resin is a bio-based urethane (meth)acrylate resin. The ultraviolet-curable paint composition of the present invention can reduce carbon dioxide emissions by using a bio-based urethane (meth)acrylate resin, unlike conventional paint compositions manufactured using urethane (meth)acrylate resins manufactured from fossil fuels.

[0025] The above bio-based urethane (meth)acrylate resin is prepared from a bio-based urethane (meth)acrylate resin composition. The bio-based urethane (meth)acrylate resin composition comprises a bio-based polyol and an isocyanate.

[0026] The above bio-based polyol may be a polyol derived from vegetable oils such as rapeseed oil, castor oil, corn oil, etc. The above bio-based polyol may include at least one selected from the group consisting of polyester polyol, polyether polyol, polycarbonate polyol, and fatty acid-modified polyol.

[0027] The above isocyanate may include at least one selected from the group consisting of isophorone diisocyanate (PDI), hexamethylene diisocyanate, isophorone diisocyanate, pentamethylene diisocyanate, cyclohexane diisocyanate, toluene diisocyanate, methylene diphenyl diisocyanate, and polyisocyanates having an isocyanurate, allophanate, or biuret structure derived from methylene diphenyl diisocyanate.

[0028] The above bio-based urethane (meth)acrylate resin composition may further include additives such as acrylic monomers, reactive diluents, catalysts, and polymerization inhibitors commonly used in the field of ultraviolet-curable paints.

[0029] The above bio-based urethane (meth)acrylate resin may include two or more types of bio-based urethane (meth)acrylate resins having different numbers of functional groups. Since the bio-based urethane (meth)acrylate resin having a low number of functional groups has a linear structure, it can easily rotate even when an external force is applied, and thus has excellent flexibility, shrinkage, and adhesion, but has poor solvent resistance and tensile strength due to low intermolecular cross-linking strength. On the other hand, the bio-based urethane (meth)acrylate resin having a high number of functional groups has high cross-linking strength, and thus has excellent solvent resistance and tensile strength, but has difficulty in rotation due to many cross-linking bonds, and thus has poor flexibility, shrinkage, and adhesion. The present invention provides an ultraviolet-curable paint composition having excellent flexibility, shrinkage, adhesion, solvent resistance, and tensile strength by including two or more types of bio-based urethane (meth)acrylate resins having different functional groups.

[0030] The above bio-based urethane (meth)acrylate resin may include a first bio-based urethane (meth)acrylate resin having a low functionality of 1 to 3 and a second bio-based urethane (meth)acrylate resin having a high functionality of 5 to 10.

[0031]

[0032] 1st bio-based urethane (meth)acrylate resin

[0033] The first bio-based urethane (meth)acrylate resin may be a 1- to 3-functional, for example, a 2-functional urethane (meth)acrylate resin. When a 1- to 3-functional urethane (meth)acrylate resin is used, it has excellent flexibility, shrinkage, and adhesion, and when applied to paint, it can further improve the film properties such as the film's adhesion, paint workability, appearance characteristics, and moisture resistance.

[0034] The first bio-based urethane (meth)acrylate resin is prepared from a first bio-based urethane (meth)acrylate resin composition. The first bio-based urethane (meth)acrylate resin composition includes a first bio-based polyol, a first acrylic monomer, and a first isocyanate.

[0035] The hydroxyl value of the first bio-based polyol may be 30 to 100 mgKOH / g, for example, 40 to 70 mgKOH / g. If the hydroxyl value is less than the aforementioned range, the urethane acrylate content may decrease, which may result in a decrease in crosslinking degree and thus a decrease in physical properties such as adhesion and chemical resistance. If the hydroxyl value exceeds the aforementioned range, the crosslinking degree may increase, which may result in a decrease in flexibility, and the molecular weight may decrease, which may result in a decrease in mechanical properties.

[0036] In addition, the number average molecular weight of the first bio-based polyol may be 800 to 3,000 g / mol, for example, 950 to 2,800 g / mol, or as another example, 1,500 to 2,500 g / mol. If the number average molecular weight is less than the above-mentioned range, the bio-content becomes lower than the standard, and if it exceeds the above-mentioned range, the bio-content increases, but the acrylate modification rate may decrease, which may lower the adhesion and chemical resistance.

[0037] The above first acrylic monomer may include at least one selected from the group consisting of 2-hydroxymethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, and caprolactone-modified (meth)acrylate.

[0038] The above first isocyanate is the same as the above-mentioned isocyanate.

[0039] The above first bio-based urethane (meth)acrylate resin composition may include 30 to 60 wt%, for example, 40 to 50 wt%, of the first bio-based polyol, 1 to 20 wt%, for example, 1 to 10 wt%, of the first acrylic monomer, and 1 to 25 wt%, for example, 5 to 15 wt%, of the first isocyanate, based on the total weight of the resin composition. If the content of the first bio-based polyol is less than the above-mentioned range, a bio-based polyol having a low molecular weight may be present in a high content, which may excessively lower the viscosity, thereby reducing workability and causing an excessive amount of unreacted substances to exist in the coating film, which may reduce adhesion. If the content exceeds the above-mentioned range, an excessive amount of unreacted polyisocyanate may exist, which may react with surrounding moisture, etc. If the content of the first acrylic monomer is less than the aforementioned range, the formation of an acrylic resin becomes difficult, and thus the number of radical sites that can react with a photoinitiator decreases, which may make crosslinking difficult. If the content of the first isocyanate is more than the aforementioned range, the polyol and isocyanate contents decrease, making it difficult to properly form a bio-resin. If the content of the first isocyanate is less than the aforementioned range, a low-molecular-weight bio-based polyol is present in a high content, which excessively lowers the viscosity, thereby reducing workability, and an excessive amount of unreacted substances may exist in the coating film, which may reduce adhesion. If the content is more than the aforementioned range, an excessive amount of unreacted polyisocyanate may exist, which may react with surrounding moisture, etc.

[0040] The bio content of the above first bio-based urethane (meth)acrylate resin may be 30 wt% or more, for example, 30 to 60 wt%, or as another example, 40 to 50 wt%, and the viscosity (25° C.) may be 3,000 to 10,000 cP, for example, 5,000 to 7,000 cP. If the bio content is less than the above-mentioned range, the bio content may be low, making it difficult to apply to automobile interior parts. If the viscosity is less than the above-mentioned range, the coating film may not be formed or the adhesion of the coating film may be reduced, and if the viscosity exceeds the above-mentioned range, the paint workability may be poor, resulting in a deterioration in the appearance of the coating film.

[0041]

[0042] Second bio-based urethane (meth)acrylate resin

[0043] The second bio-based urethane (meth)acrylate resin may be a 5- to 10-functional, for example, 6-functional urethane (meth)acrylate resin. When a 5- to 10-functional urethane (meth)acrylate resin is used, the solvent resistance and tensile strength are excellent, and when applied to a paint, the surface hardness and curing speed of the paint film can be further improved.

[0044] The second bio-based urethane (meth)acrylate resin is prepared from a second bio-based urethane (meth)acrylate resin composition. The second bio-based urethane (meth)acrylate resin composition includes a second bio-based polyol, a second acrylic monomer, and a second isocyanate.

[0045] The hydroxyl value of the second bio-based polyol may be 150 to 250 mgKOH / g, for example, 175 to 215 mgKOH / g. If the hydroxyl value is less than the aforementioned range, the content of urethane acrylate decreases, which may result in a decrease in crosslinking degree and thus a decrease in physical properties such as adhesion and chemical resistance. If the hydroxyl value exceeds the aforementioned range, the degree of crosslinking increases, which may result in a decrease in flexibility, and a decrease in molecular weight may result in a decrease in mechanical properties.

[0046] The number average molecular weight of the second bio-based polyol may be 300 to 1,500 g / mol, for example 300 to 1,000 g / mol, or as another example 450 to 700 g / mol. If the number average molecular weight is less than the aforementioned range, the bio-content may be lower than the standard, and if it exceeds the aforementioned range, the bio-content may increase, but the acrylate modification rate may be lowered, which may lower the adhesion and chemical resistance.

[0047] The second acrylic monomer may include at least one selected from the group consisting of pentaerythritol triacrylate (PETA) and dipentaerythritol pentaacrylate.

[0048] The above second isocyanate is the same as the above-mentioned isocyanate.

[0049] For example, the second bio-based urethane (meth)acrylate resin composition may include 10 to 40 wt%, for example, 15 to 30 wt%, of the second bio-based polyol, 1 to 30 wt%, for example, 10 to 30 wt%, of the second acrylic monomer, and 5 to 40 wt%, for example, 10 to 30 wt%, of the second isocyanate, based on the total weight of the resin composition. If the content of the second bio-based polyol is less than the above-mentioned range, a bio-based polyol having a low molecular weight may be present in a high content, which may excessively lower the viscosity, thereby reducing workability and causing an excessive amount of unreacted substances to exist in the coating film, which may reduce adhesion. If the content exceeds the above-mentioned range, an excessive amount of unreacted polyisocyanate may exist, which may react with surrounding moisture, etc. If the content of the second acrylic monomer is less than the aforementioned range, the formation of an acrylic resin becomes difficult, and thus the number of radical sites that can react with a photoinitiator decreases, which may make crosslinking difficult. If the content of the second isocyanate is more than the aforementioned range, the polyol and isocyanate contents decrease, making it difficult to properly form a bio-resin. If the content of the second isocyanate is less than the aforementioned range, a bio-based polyol with a low molecular weight is present in a high content, which excessively lowers the viscosity, thereby reducing workability, and an excessive amount of unreacted substances may exist in the coating film, which may reduce adhesion. If the content is more than the aforementioned range, an excessive amount of unreacted polyisocyanate may exist, which may react with surrounding moisture, etc.

[0050] The bio content of the above second bio-based urethane (meth)acrylate resin may be 20 wt% or more, for example, 20 to 50 wt%, or as another example, 30 to 40 wt%, and the viscosity (25° C.) may be 10,000 to 25,000 cP, for example, 15,000 to 20,000 cP. If the bio content is less than the above-mentioned range, the bio content may be low, making it difficult to apply to automobile interior parts. If the viscosity is less than the above-mentioned range, the coating film may not be formed or the adhesion of the coating film may be reduced, and if it exceeds the above-mentioned range, the paint workability may be poor, resulting in a deterioration in the appearance of the coating film.

[0051]

[0052] The ultraviolet-curable paint composition of the present invention may contain 6 to 60 wt%, for example, 11 to 40 wt%, of the bio-based urethane (meth)acrylate resin based on the total weight of the paint composition.

[0053] For example, the UV-curable paint composition of the present invention may include 5 to 40 wt%, for example, 10 to 30 wt%, of the first bio-based urethane (meth)acrylate resin and 1 to 20 wt%, for example, 1 to 10 wt%, of the second bio-based urethane (meth)acrylate resin, based on the total weight of the paint composition. When the content of the first bio-based urethane (meth)acrylate resin is less than the above-mentioned range, flexibility, shrinkage, and adhesion may be reduced, and when it exceeds the above-mentioned range, solvent resistance and tensile strength may be reduced. When the content of the second bio-based urethane (meth)acrylate resin is less than the above-mentioned range, solvent resistance and tensile strength may be reduced, and when it exceeds the above-mentioned range, flexibility, shrinkage, and adhesion may be reduced.

[0054]

[0055] (meth)acrylate monomer

[0056] The ultraviolet-curable coating composition of the present invention comprises a (meth)acrylate monomer. The (meth)acrylate monomer is an auxiliary component of a dry coating film, which reduces the viscosity of the coating composition, thereby improving flowability, leveling properties, and workability, and at the same time improving the iodine resistance, scratch resistance, and adhesion of the coating film.

[0057] The above (meth)acrylate monomer may be a mono- to tri-functional, for example, a di-functional (meth)acrylate monomer.

[0058] For example, the (meth)acrylate monomer may include at least one selected from the group consisting of 1,6-hexanediol diacrylate (HDDA), lauryl acrylate, tetrahydrofurfuryl acrylate, isobornyl acrylate, 1,10-decanediol diacrylate, polyethylene glycol diacrylate, trimethylolpropane triacrylate, and glycerin triacrylate.

[0059] The molecular weight of the above (meth)acrylate monomer may be 150 to 350 g / mol, for example, 200 to 300 g / mol. If the molecular weight is less than the above-mentioned range, the viscosity of the paint may be too low due to excessive inclusion of low-molecular substances, which may prevent the paint from forming an appropriate film thickness and may cause it to flow, making painting difficult. If the molecular weight is greater than the above-mentioned range, the viscosity of the paint may be high due to the inclusion of a small amount of low-molecular substances, which may reduce workability.

[0060] The ultraviolet-curable paint composition of the present invention may contain 1 to 20 wt%, for example, 5 to 10 wt%, of the (meth)acrylate monomer based on the total weight of the paint composition. If the content of the (meth)acrylate monomer is less than the above-mentioned range, the viscosity of the paint may be too low, failing to form an appropriate film thickness and causing it to flow, resulting in poor painting. If the content exceeds the above-mentioned range, the viscosity of the paint may be high, resulting in poor workability.

[0061]

[0062] acrylic resin

[0063] The ultraviolet-curable paint composition of the present invention may further include an acrylic resin. In this case, physical properties such as adhesion and paint flowability can be further improved.

[0064] The acid value of the above acrylic resin may be 10 to 50 mgKOH / g, for example, 20 to 40 mgKOH / g.

[0065] The ultraviolet-curable paint composition of the present invention may contain 1 to 20 wt%, for example, 1 to 10 wt%, of the acrylic resin based on the total weight of the paint composition.

[0066]

[0067] photoinitiator

[0068] The UV-curable coating composition of the present invention includes a photoinitiator. The photoinitiator is a component that initiates photopolymerization when excited by ultraviolet rays or the like. Any photoinitiator generally known in the relevant technical field may be used without limitation.

[0069] Non-limiting examples of available photoinitiators include MICURE BP, JRCURE MBF, Irgacure 184, Irgacure 369, Irgacure 651, Irgacure 819, Irgacure 907, Benzionalkylether, Benzophenone, Benzyl dimethyl katal, Hydroxycyclohexyl phenylacetone, Chloro acetophenone, 1,1-Dichloro acetophenone, Diethoxy acetophenone, Hydroxy Acetophenone, 2-Choro thioxanthone, 2-ETAQ (2-EthylAnthraquinone), 1-Hydroxy-cyclohexylphenyl-ketone, 2-Hydroxy-2-methyl-1-phenyl-1-propanone, 2-Hydroxy-2-methylpropiophenone, 2-Hydroxy-1-[4-(2-hydroxyethoxy)phenyl]-2-methyl-1-propanone, methylbenzoylformate, phenylbis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, phenylbis(2,4,6-trimethylbenzoyl)phosphine There are oxide, 2-hydroxy-2-methyl-1-phenylpropan-1-one, etc. These can be used alone or in combination of two or more.

[0070] The UV-curable coating composition of the present invention may contain 0.1 to 10 wt%, for example 1 to 5 wt%, of the photoinitiator based on the total weight of the coating composition. If the content of the photoinitiator is less than the above-mentioned range, the coating film strength and adhesion may be reduced due to reduced curing or non-curing, and if it exceeds the above-mentioned range, contamination due to unreacted photoinitiator or reduced adhesion due to low polymerization degree may occur.

[0071]

[0072] additives

[0073] In addition to the aforementioned components, the UV-curable coating composition of the present invention may optionally further include additives commonly used in the relevant technical field, depending on the intended use and environment of the coating composition. For example, additives such as solvents, UV absorbers, surface conditioners, adhesion promoters, dispersants, polymerization inhibitors, and matting agents may be further included, as needed.

[0074] The solvent improves the solubility and reduces the viscosity of the paint composition, thereby enabling spray painting. As the solvent, any organic solvent known in the art can be used without particular limitation, and examples thereof include butyl acetate, isobutyl alcohol, and ethyl acetate. The solvent can be included in an amount satisfying 100 wt% of the total paint composition, and for example, can be included in an amount of 10 to 60 wt%, for example, 20 to 50 wt%, based on the total weight of the paint composition.

[0075] The UV absorber absorbs UV rays to protect the coating film, and any known material in the relevant technical field can be used without particular limitation. For example, 2-hydroxyphenyl-S-triazine, HALS (hindered amine light stabilizer), etc. can be used. The surface conditioner reduces the surface tension of the paint to improve the leveling property, and any known material in the relevant technical field can be used without particular limitation. For example, a siloxane-based surface conditioner such as polyether-modified polydimethyl siloxane can be used.

[0076] The content of each of the above additives is not particularly limited, and may be, for example, 0.01 to 20 wt% based on the total weight of the paint composition.

[0077]

[0078] The present invention will be described in more detail through the following examples. However, the following examples are intended only to aid understanding of the present invention and are not intended to limit the scope of the present invention in any way.

[0079]

[0080] [Manufacturing Example 1-1: Manufacturing of the first bio-based urethane (meth)acrylate resin 1-1]

[0081] In a reactor equipped with a thermometer, a stirring device, a reflux condenser, an air injection device, and a nitrogen injection device, 50 g of bio-based polyester polyol (100% solid content, 14,000 mpas, 100 wt% bio content, 56 mgKOH / g hydroxyl value, 2,004 g / mol number average molecular weight), 22.5 g of trimethylolpropane triacrylate, 22.5 g of hexanediol diacrylate, and 11.1 g of isophorone diisocyanate were added under nitrogen injection, and the temperature was raised to 40°C while stirring. At 40°C, 0.01 g of dibutyl tin dilaurate was added, and while confirming exotherm, the temperature was raised to 70°C and maintained for 2 hours. The temperature was maintained and tracked until the NCO% reached 1.9% through NCO% wet measurement. When the NCO% reached 1.9%, 6.1 g of hydroxyethyl acrylate and 0.015 g of dibutylhydroxytoluene were added, and the temperature was raised to 90°C to maintain the reaction until the NCO% became 0.05% or less. When the NCO% became 0.05% or less, the reaction was terminated, and the first bio-based urethane (meth)acrylate resin 1-1 of Manufacturing Example 1-1 was manufactured (bifunctional, solid content 100%, viscosity (25°C) 6,000 cPS, Bio Content 45 wt%).

[0082]

[0083] [Manufacturing Example 1-2: Manufacturing of the first bio-based urethane (meth)acrylate resin 1-2]

[0084] In a reactor equipped with a thermometer, a stirring device, a reflux condenser, an air injection device, and a nitrogen injection device, 44.614 g of bio-based polyester polyol (100% solid content, 1,800 mpas, 100 wt% bio content, 55 mgKOH / g hydroxyl value, 2,040 g / mol number average molecular weight), 20 g of trimethylolpropane triacrylate, 20 g of hexanediol diacrylate, and 9.917 g of isophorone diisocyanate were charged under nitrogen injection, and the temperature was raised to 40°C while stirring. At 40°C, 0.012 g of dibutyl tin dilaurate was charged, and while confirming exotherm, the temperature was raised to 70°C and maintained for 2 hours. The temperature was maintained and tracked until the NCO% through NCO% wet measurement reached 1.98%. When the NCO% reached 1.98%, 5.443 g of hydroxyethyl acrylate and 0.014 g of dibutylhydroxytoluene were added, and the temperature was raised to 90°C to maintain the reaction until the NCO% became 0.05% or less. When the NCO% became 0.05% or less, the reaction was terminated, and the first bio-based urethane (meth)acrylate resin 1-2 of Manufacturing Example 1-2 was manufactured (bifunctional, solid content 100%, viscosity (25°C) 3,000 cPS, Bio Content 45 wt%).

[0085]

[0086] [Manufacturing Example 1-3: Manufacturing of the first non-bio-based urethane (meth)acrylate resin]

[0087] In a reactor equipped with a thermometer, a stirring device, a reflux condenser, an air injection device, and a nitrogen injection device, 50 g of polyester polyol (biocontent 0 wt%, hydroxyl value 56 mgKOH / g, number average molecular weight 2,004 g / mol), 22.5 g of trimethylolpropane triacrylate, 22.5 g of hexanediol diacrylate, and 11.1 g of isophorone diisocyanate were charged under nitrogen injection, and the temperature was raised to 40°C while stirring. At 40°C, 0.01 g of dibutyl tin dilaurate was added, and while confirming exotherm, the temperature was raised to 70°C and maintained for 2 hours. The temperature was maintained and tracked until the NCO% reached 1.9% through NCO% wet measurement. When the NCO% reached 1.9%, 6.1 g of hydroxyethyl acrylate and 0.015 g of dibutylhydroxytoluene were added, and the temperature was raised to 90°C to maintain the reaction until the NCO% became 0.05% or less. When the NCO% became 0.05% or less, the reaction was terminated, and the first urethane (meth)acrylate resin of Manufacturing Example 1-3 was manufactured (bifunctional, solid content 100%, viscosity (25°C) 7,000 cPS, Bio Content 0 wt%). The first urethane (meth)acrylate resin of Manufacturing Example 1-3 is a non-bio-based urethane (meth)acrylate resin that does not contain a biomaterial.

[0088]

[0089] [Manufacturing Example 2-1: Manufacturing of Second Bio-Based Urethane (Meth)Acrylate Resin 2-1]

[0090] In a reactor equipped with a thermometer, a stirring device, a reflux condenser, an air injection device, and a nitrogen injection device, 17.562 g of bio-based fatty acid-modified polyol (100% solid content, 2,750 mpas, 100 wt% bio content, 202 mgKOH / g hydroxyl value, 583 g / mol number average molecular weight), 20.02 g of trimethylolpropane triacrylate, 20.02 g of hexanediol diacrylate, and 14.056 g of isophorone diisocyanate were added under nitrogen injection, and the temperature was raised to 40°C while stirring. At 40°C, 0.012 g of dibutyl tin dilaurate was added, and while confirming exotherm, the temperature was raised to 70°C and maintained for 2 hours. The temperature was maintained and tracked until the NCO% reached 3.7% through NCO% wet measurement. When the NCO% reached 3.7%, 28.309 g of pentaerythritol triacrylate and 0.021 g of dibutylhydroxytoluene were added, and the temperature was raised to 90°C to maintain the reaction until the NCO% became 0.05% or less. When the NCO% became 0.05% or less, the reaction was terminated, and the second bio-based urethane (meth)acrylate resin 2-1 of Manufacturing Example 2-1 was manufactured (6 functionalities, solid content 100%, viscosity (25°C) 12,000 cPS, Bio Content 18 wt%).

[0091]

[0092] [Manufacturing Example 2-2: Manufacturing of Second Bio-Based Urethane (Meth)Acrylate Resin 2-2]

[0093] In a reactor equipped with a thermometer, a stirring device, a reflux condenser, an air injection device, and a nitrogen injection device, 17.868 g of bio-based polyether polyol (100% solid content, 1,200 mpas viscosity, 100 wt% bio content, 200 mgKOH / g hydroxyl value, 617 g / mol number average molecular weight), 20 g of trimethylolpropane triacrylate, 20 g of hexanediol diacrylate, and 13.920 g of isophorone diisocyanate were added under nitrogen injection, and the temperature was raised to 40°C while stirring. At 40°C, 0.012 g of dibutyl tin dilaurate was added, and while confirming exotherm, the temperature was raised to 70°C and maintained for 2 hours. The temperature was maintained and tracked until the NCO% reached 3.6% through NCO% wet measurement. When the NCO% reached 3.6%, 28.178 g of pentaerythritol triacrylate and 0.020 g of dibutylhydroxytoluene were added, and the temperature was raised to 90°C to maintain the reaction until the NCO% became 0.05% or less. When the NCO% became 0.05% or less, the reaction was terminated, and the second bio-based urethane (meth)acrylate resin 2-2 of Manufacturing Example 2-2 was manufactured (6 functionalities, solid content 100%, viscosity (25°C) 9,000 cPS, Bio Content 18 wt%).

[0094]

[0095] [Manufacturing Example 2-3: Manufacturing of a Second Bio-Based Urethane (Meth)Acrylate Resin]

[0096] In a reactor equipped with a thermometer, a stirring device, a reflux condenser, an air injection device, and a nitrogen injection device, 17.562 g of fatty acid-modified polyol (100% solid content, 0 wt% bio-content, 202 mgKOH / g hydroxyl value, 2,000 mpas viscosity, 583 g / mol number average molecular weight), 20.02 g of trimethylolpropane triacrylate, 20.02 g of hexanediol diacrylate, and 14.056 g of isophorone diisocyanate were charged under nitrogen injection, and the temperature was raised to 40°C while stirring. At 40°C, 0.012 g of dibutyl tin dilaurate was added, and while confirming exotherm, the temperature was raised to 70°C and maintained for 2 hours. The temperature was maintained and tracked until the NCO% reached 3.7% through NCO% wet measurement. When the NCO% reached 3.7%, 28.309 g of pentaerythritol triacrylate and 0.021 g of dibutylhydroxytoluene were added, and the temperature was raised to 90°C to maintain the reaction until the NCO% became 0.05% or less. When the NCO% became 0.05% or less, the reaction was terminated, and the second urethane (meth)acrylate resin of Manufacturing Example 2-3 was manufactured (solid content 100%, viscosity (25°C) 11,000 cPS, Bio Content 0 wt%). The second urethane (meth)acrylate resin of Manufacturing Example 2-3 is a non-bio-based urethane (meth)acrylate resin that does not contain a biomaterial.

[0097]

[0098] [Experimental Example 1-13]

[0099] According to the compositions described in Tables 1 and 2 below, ultraviolet-curable paint compositions for each experimental example were prepared.

[0100]

[0101]

[0102]

[0103]

[0104] Urethane acrylate 1-1: The first bio-based urethane (meth)acrylate resin 1-1 of Manufacturing Example 1-1 (bifunctional, NV 100%, viscosity (25°C) 6,000 cPS, Bio Content 45 wt%)

[0105] Urethane acrylate 1-2: The first bio-based urethane (meth)acrylate resin 1-2 of Manufacturing Example 1-2 (bifunctional, NV 100%, viscosity (25 ℃) 3,000 cPS, Bio Content 45 wt%)

[0106] Urethane Acrylate 1-3: The first non-bio-based urethane (meth)acrylate resin of Manufacturing Example 1-3 (bifunctional, NV 100%, viscosity (25 ℃) 7,000 cPS, Bio Content 0 wt%)

[0107] Urethane acrylate 2-1: The second bio-based urethane (meth)acrylate resin 2-1 of Manufacturing Example 2-1 (hexafunctional, NV 100%, viscosity (25 ℃) 12,000 cPS, Bio Content 18 wt%)

[0108] Urethane acrylate 2-2: The second bio-based urethane (meth)acrylate resin 2-2 of Manufacturing Example 2-2 (hexafunctional, NV 100%, viscosity (25 ℃) 9,000 cPS, Bio Content 18 wt%)

[0109] Urethane acrylate 2-3: The second non-bio-based urethane (meth)acrylate resin of Manufacturing Example 2-3 (hexafunctional, NV 100%, viscosity (25 ℃) 11,000 cPS, Bio Content 0 wt%)

[0110] HDDA: 1,6-hexanediol diacrylate

[0111] Photoinitiator 1: DAROCURE 1173

[0112] Photoinitiator 2: IRGACURE 819

[0113] Solvent 1: Butyl acetate

[0114] Solvent 2: Isobutyl alcohol

[0115] UV absorber 1: TINUVIN 400

[0116] UV absorber 2: TINUVIN-123

[0117] Surface conditioner: BYK 306

[0118] Acrylic resin: Synthalat A-TS 1558 (manufacturer: Synthopol Chemie)

[0119]

[0120] [Physical property evaluation - bio-content]

[0121] According to ASTM D6866, the bio-content of the UV-curable paint composition manufactured in each experimental example was measured by the following method, and the results are shown in Table 3 below. A bio-content of 15 wt% or more was judged to be acceptable.

[0122]

[0123]

[0124]

[0125] [Property Evaluation - Paint Properties]

[0126] For the paints of each experimental example, specimens were prepared using the following method and the paint properties were evaluated, which are shown in Tables 4 and 5. However, for the paint compositions of experimental examples 9, 11, and 13, which showed low bio-contents, the paint properties were not measured.

[0127]

[0128] Sample manufacturing

[0129] The paint composition of each experimental example was applied (thickness: 20-30 ㎛) on the plastic of an automobile interior part and photocured (light quantity: 1,000 mJ / cm2, light intensity: 140 mW / cm2) to prepare a specimen.

[0130]

[0131] appearance

[0132] Each specimen was visually observed for defects such as swelling, peeling, surface cracks, pinholes, bubbles, and foreign matter, and the appearance was evaluated according to the following criteria.

[0133] [metewand]

[0134] Excellent (◎): No defects (surface cracks, bubbles, etc.)

[0135] Defective (X): Occurrence of defects (surface cracks, bubbles, etc.)

[0136]

[0137] Scratch resistance

[0138] Using a sapphire scratcher (load 4.9 N (0.5 kgf), friction speed 100 mm / sec, stroke 100 mm) of the shape shown in Figure 1 below, the surface of the specimen was scratched once, and then the surface condition was observed to evaluate the scratch resistance.

[0139] [metewand]

[0140] Grade 5: No surface damage is recognized.

[0141] Grade 4: Slightly noticeable surface damage

[0142] Grade 3: Some surface damage is noticeable, but not severe.

[0143] Grade 2: Surface damage is recognized.

[0144] Grade 1: Surface damage is significantly visible.

[0145] Passing Criteria: Level 4 or higher

[0146]

[0147] Adhesiveness

[0148] The cross-cut tape test was performed according to ASTM D3359 to evaluate the adhesiveness. 100 scratches were made on the surface, each measuring 1 mm X 1 mm in width and height, using a cross cutter, and the number of scratches that remained adhered to the coating out of 100 were counted when the tape was attached with Nichiban tape. The adhesiveness was evaluated according to the following criteria. In cases where the intermediate properties of each classification were observed, the intermediate value (e.g., M-1.5, M-2.5) was used for evaluation.

[0149] [metewand]

[0150] M-1.0: Meets IS0 2409 CLASS 0 and delamination of less than 50% of the total area of ​​1 cell

[0151] M-2.0: Meets IS0 2409 CLASS 1 and has a total delamination area of ​​less than 5%

[0152] M-3.0: Meets IS0 2409 CLASS 2, with a total peeling area of ​​5% or more and less than 15%.

[0153] M-4.0: Meets IS0 2409 CLASS 3, with a total peeling area of ​​15% or more and less than 35%.

[0154] M-5.0: Meets IS0 2409 CLASS 4, and total peeling area is 35% or more and less than 65%.

[0155] M-6.0: Fully peeled

[0156] Passing Criteria: M-2.5 or less

[0157]

[0158] Impact resistance

[0159] Using the drop tester of ISO 6272-2, an impact was applied to the coating surface of each specimen (room temperature, weight of 4.9 N (0.5 kgf), drop height of 20 cm, core diameter of 12.7 mm (0.5 inch)), and the condition of the coating was checked, and the impact resistance was evaluated based on the following criteria.

[0160] [metewand]

[0161] Pass (◎): No minor cracks or peeling

[0162] Fail (X): Peeling occurred

[0163]

[0164] moisture resistance

[0165] Each specimen was left for 168 hours at 50±2 ℃, 95±2% conditions, taken out, left for 1 hour, and then moisture resistance was evaluated using the same method as the adhesiveness described above.

[0166] [metewand]

[0167] Passing Criteria: M-2.5 or less

[0168]

[0169] Chemical resistance

[0170] After immersing each specimen in 5% NaOH and 5% HCl for 24 hours, the appearance of the coating was observed and the chemical resistance was evaluated according to the criteria shown in Figure 2 below.

[0171] [metewand]

[0172] Passing Criteria: Gray Scale Level 3 or higher

[0173]

[0174] My sunscreen

[0175] Two sheets of cotton cloth (equivalent to Toyosynthetic CH2070-3) of the same size were placed on an acrylic plate (50 mm X 50 mm, width X height), and 0.25 g of sunscreen (Nivea SPF47) was applied to the entire surface. The sunscreen application area was placed on the coating of each specimen and the acrylic plate was pressed to adhere it. After that, it was left in a constant temperature bath at 80±2℃ for 1 hour, taken out, the cotton cloth and acrylic plate were removed, and left at room temperature for 10 minutes. After that, it was washed with a neutral detergent, dried, and the sunscreen resistance was evaluated in the same manner as the adhesion described above.

[0176] [metewand]

[0177] Passing Criteria: M-2.5 or less

[0178]

[0179] Heat cycle resistance

[0180] Each specimen was sequentially left at 80±2℃ for 3 hours, room temperature for 1 hour, 40±2℃ for 3 hours, room temperature for 1 hour, 50±2℃ 95±2%RH for 7 hours, and room temperature for 1 hour, and 3 cycles were performed. After taking the specimen out and leaving it at room temperature for 1 hour, the surface condition of the coating film was checked and the heat cycle resistance was evaluated using the same method as the adhesiveness described above.

[0181] [metewand]

[0182] Passing Criteria: M-2.5 or less

[0183]

[0184] Heat resistance

[0185] Each specimen was left for 300 hours under conditions of 90±2 ℃, taken out, and left at room temperature for 1 hour. The surface condition of the coating was checked, and heat resistance was evaluated using the same method as the adhesiveness described above.

[0186] [metewand]

[0187] Passing Criteria: M-2.5 or less

[0188]

[0189] Lightfastness

[0190] Using Xenon arc (BORO SILICATE (inner filter) / SODA LIME (outer filter)), 84 MJ / m² (700 KJ / m) 2 ), the specimens were irradiated under conditions of a black panel temperature of 89±3℃ and an internal humidity of 50±5% RH with an illuminance of 65.5±2.5 W / m² (300-400 nm). After irradiation, the specimens were washed with a neutral detergent to remove surface moisture, and left at room temperature for 1 hour. Then, the light resistance was evaluated using the same method as the adhesion described above.

[0191] [metewand]

[0192] Passing Criteria: M-2.5 or less

[0193]

[0194] wear resistance

[0195] Using a reciprocating wear tester (load 4.9 N{kgf}, speed 30 reciprocations / min, width 20 X 20 mm, stroke 100 mm) made of KS K1450 material with a shape shown in Figure 3 below, a reciprocating test was conducted 1,000 times, and then the wear resistance was evaluated according to the evaluation criteria below.

[0196] [metewand]

[0197] Pass criteria: After 1,000 tests, there should be no damage to the pattern / color (however, changes in gloss due to wear and surface damage due to wearers are allowed).

[0198]

[0199] My life is scratchy

[0200] Using the reciprocating abrasion tester used in the aforementioned abrasion resistance test, 300 reciprocating tests were performed under the following test conditions, and each test piece was wiped with an ultra-fine non-woven fabric (1 denier or less) to prevent scratches. Then, each test piece was placed on a table and the appearance of the effective surface (16 X 60 mm) was visually observed from a distance of 50 cm under natural light or an artificial light source of 6,500 K, and the scratch resistance to daily life was evaluated according to the evaluation criteria below.

[0201] [metewand]

[0202] Pass criteria: No surface scratches

[0203]

[0204]

[0205]

[0206]

[0207] As shown in Tables 4 and 5 above, the paint compositions of Experimental Examples 1-8 according to the present invention exhibited excellent physical properties across all measured items. On the other hand, the paint composition of Experimental Example 9, which included a non-bio-based urethane (meth)acrylate resin (urethane acrylate 1-3) instead of the first bio-based urethane (meth)acrylate resin that did not contain a biomaterial, had a bio content that did not meet the passing standard, and the paint composition of Experimental Example 10, which used a non-bio-based urethane (meth)acrylate resin (urethane acrylate 2-3) instead of the second bio-based urethane (meth)acrylate resin, exhibited poor adhesion, moisture resistance, sunscreen resistance, heat cycle resistance, heat resistance, and light resistance. In addition, the paint composition of Experimental Example 11, which included two types of non-bio-based urethane (meth)acrylate resins (urethane acrylate 1-3 and urethane acrylate 2-3) that did not contain biomaterials, had a biocontent that did not meet the passing standard, the paint composition of Experimental Example 12, which did not include the second bio-based urethane (meth)acrylate resin, showed poor appearance, impact resistance, abrasion resistance, and scratch resistance, and the paint composition of Experimental Example 13, which did not include the first bio-based urethane (meth)acrylate resin, had a biocontent that did not meet the passing standard. No property evaluation was performed on the paint compositions of Experimental Examples 9, 11, and 13, which had biocontents that did not meet the passing standard.

[0208]

[0209] The present invention provides an environmentally friendly ultraviolet-curable paint composition capable of minimizing carbon dioxide emissions.

Claims

1. Contains bio-based urethane (meth)acrylate resin, (meth)acrylate monomer and photoinitiator, The above bio-based urethane (meth)acrylate resin includes a first bio-based urethane (meth)acrylate resin and a second bio-based urethane (meth)acrylate resin, The above first bio-based urethane (meth)acrylate resin comprises a 1 to 3 functional urethane (meth)acrylate resin, The second bio-based urethane (meth)acrylate resin is an ultraviolet-curable paint composition comprising a 5 to 10-functional urethane (meth)acrylate resin.

2. In the first paragraph, the first bio-based urethane (meth)acrylate resin is manufactured from the first bio-based urethane (meth)acrylate resin composition, The first bio-based urethane (meth)acrylate resin composition comprises a first bio-based polyol, a first acrylic monomer, and a first isocyanate, The hydroxyl value of the first bio-based polyol is 30 to 100 mgKOH / g, and the number average molecular weight is 800 to 3,000 g / mol, The first acrylic monomer comprises at least one selected from the group consisting of 2-hydroxymethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, and caprolactone-modified (meth)acrylate. The second bio-based urethane (meth)acrylate resin is prepared from a second bio-based urethane (meth)acrylate resin composition, The second bio-based urethane (meth)acrylate resin composition comprises a second bio-based polyol, a second acrylic monomer, and a second isocyanate, The hydroxyl value of the second bio-based polyol is 150 to 250 mgKOH / g, and the number average molecular weight is 300 to 1,500 g / mol, An ultraviolet-curable paint composition comprising the second acrylic monomer at least one selected from the group consisting of pentaerythritol triacrylate (PETA) and dipentaerythritol pentaacrylate.

3. In the second paragraph, the first bio-based urethane (meth)acrylate resin composition comprises 30 to 60 wt% of the first bio-based polyol, 1 to 20 wt% of the first acrylic monomer, and 1 to 25 wt% of the first isocyanate, based on the total weight of the resin composition. The second bio-based urethane (meth)acrylate resin composition is an ultraviolet-curable paint composition comprising 10 to 40 wt% of the second bio-based polyol, 1 to 30 wt% of the second acrylic monomer, and 5 to 40 wt% of the second isocyanate, based on the total weight of the resin composition.

4. In the first paragraph, the bio content of the first bio-based urethane (meth)acrylate resin is 30 wt% or more, and the viscosity (25°C) is 3,000 to 10,000 cp, An ultraviolet-curable paint composition having a bio content of the second bio-based urethane (meth)acrylate resin of 20 wt% or more and a viscosity (25°C) of 10,000 to 25,000 cp.

5. In the first paragraph, the (meth)acrylate monomer includes at least one selected from the group consisting of 1,6-hexanediol diacrylate (HDDA), lauryl acrylate, tetrahydrofurfuryl acrylate, isobornyl acrylate, 1,10-decanediol diacrylate, polyethylene glycol diacrylate, trimethylolpropane triacrylate, and glycerin triacrylate. An ultraviolet-curable paint composition wherein the molecular weight of the (meth)acrylate monomer is 150 to 350 g / mol.

6. An ultraviolet-curable paint composition having a bio content (based on solid content) of 15 wt% or more in the first paragraph.

7. An ultraviolet-curable paint composition comprising, in paragraph 1, 5 to 40 wt% of the first bio-based urethane (meth)acrylate resin, 1 to 20 wt% of the second bio-based urethane (meth)acrylate resin, 1 to 20 wt% of the (meth)acrylate monomer, and 0.1 to 10 wt% of the photoinitiator, based on the total weight of the paint composition.

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