Base coat composition for plastics

Abstract

The present invention relates to a base coat composition for plastics, the base coat composition comprising: a first acrylic polyol; a second acrylic polyol; a third acrylic polyol; an isocyanate-based curing agent; and a solvent, wherein the first acrylic polyol has a glass transition temperature of -10°C to 10°C, the second acrylic polyol has a glass transition temperature of 80°C to 110°C, and the third acrylic polyol has a glass transition temperature of 40°C to 60°C.

Description

Base paint composition for plastics

[0001] The present invention relates to a base paint composition for plastic that can form a cured film having excellent adhesion to plastic and excellent chemical resistance, fragrance resistance, sunscreen resistance, heat resistance, and light resistance.

[0002] Plastics used in automotive interior components are typically painted to enhance their aesthetic appeal and protect their surfaces from the external environment. Paint treatment typically involves pretreatment to enhance the surface tension between the plastic part and the paint, primer coating to enhance adhesion between the plastic part and the base coat, and base and clear coats to enhance and protect the plastic part's appearance.

[0003] At this time, polypropylene (PP), nylon, or thermoplastic polyolefin (TPO) are typically used as plastic materials for automobile interior parts. The base paint and clear paint for these plastic parts typically include thermosetting resins, such as polyester, amino acrylic, polyester-urethane, acrylic-urethane, polyester-melamine, and acrylic-melamine resins.

[0004] Meanwhile, in recent years, the use of chemical substances such as air fresheners and sunscreens has increased in line with changes in driver and passenger trends in automobile interiors. As a result, problems such as the exterior of automobile interior parts peeling off due to solvents in air fresheners or handprints left by sunscreens have occurred, and thus, paints with improved chemical resistance that can protect the exterior from chemicals are in demand.

[0005] In this regard, Korean Patent No. 2,370,986 (Patent Document 1) discloses a paint composition comprising an acrylic resin and a solvent, with a solids content of 55 to 60 wt%. However, conventional paint compositions such as Patent Document 1 have problems such as high viscosity, resulting in poor workability, and poor chemical resistance of the resulting coating film.

[0006] Therefore, there is a need for research and development of a base paint composition that has excellent adhesion to plastic materials and a manufactured coating film that has excellent various physical properties such as chemical resistance, fragrance resistance, sunscreen resistance, heat resistance, and light resistance.

[0007] Accordingly, the present invention provides a base paint composition for plastics having excellent adhesion to plastic materials and a manufactured coating film having excellent various physical properties such as chemical resistance, fragrance resistance, sunscreen resistance, heat resistance, and light resistance.

[0008] The present invention comprises a first acrylic polyol, a second acrylic polyol, a third acrylic polyol, an isocyanate curing agent and a solvent,

[0009] The above first acrylic polyol has a glass transition temperature of -10°C to 10°C,

[0010] The above second acrylic polyol has a glass transition temperature of 80°C to 110°C,

[0011] The above third acrylic polyol provides a base paint composition for plastic having a glass transition temperature of 40°C to 60°C.

[0012] The base paint composition according to the present invention comprises three types of acrylic polyols having different glass transition temperatures (Tg), thereby exhibiting excellent adhesion to plastic materials, and the resulting coating film exhibits excellent various physical properties, including chemical resistance, fragrance resistance, sunscreen resistance, heat resistance, and light resistance. Therefore, the base paint composition of the present invention is highly suitable for application to plastic materials such as automotive interior parts, and particularly as a base paint for plastics.

[0013] The present invention is described in detail below.

[0014] The “weight average molecular weight” used herein refers to the average molecular weight obtained by averaging the molecular weights of the component molecular species of a polymer compound by weight fraction. The higher the weight average molecular weight, the higher the intermolecular force with the primer composition when the same amount of paint is applied, resulting in excellent adhesion and film-forming ability. However, if the weight average molecular weight is excessively high, the viscosity of the polymer compound may be high, resulting in poor workability. This “weight average molecular weight” is measured by a conventional method known in the art, and can be measured, for example, by a GPC (gel permeation chromatography) method.

[0015] Additionally, the “glass transition temperature” is measured by a conventional method known in the art, and can be measured by, for example, differential scanning calorimetry (DSC).

[0016] Furthermore, functional groups and / or functional group content such as “acid value”, “hydroxyl value” and “content of isocyanate group” can be measured by methods well known in the art, and for example, can represent values ​​measured by a titration method.

[0017] In this specification, “(meth)acrylic” means “acrylic” and / or “methacrylic”, and “(meth)acrylate” means “acrylate” and / or “methacrylate”.

[0018] A base paint composition according to the present invention comprises a first acrylic polyol, a second acrylic polyol, a third acrylic polyol, an isocyanate-based curing agent, and a solvent.

[0019] Specifically, the base paint composition includes three types of acrylic polyols having different glass transition temperatures (Tg), thereby making it difficult for chemicals to penetrate, and thus providing excellent chemical resistance to the manufactured coating film.

[0020] The above acrylic polyol may be synthesized by a radical reaction of a vinyl monomer and an acrylic monomer, and at this time, the glass transition temperature of the manufactured acrylic polyol can be controlled by adjusting the type and / or content of the vinyl monomer and the acrylic monomer.

[0021] The above vinyl monomer is not particularly limited in type, but may include, for example, one or more selected from the group consisting of styrene, methylstyrene, dimethylstyrene, ethoxystyrene, and methoxystyrene.

[0022] In addition, the type of the acrylic monomer is not particularly limited, but may include (meth)acrylic acid, methyl (meth)acrylic acid, (meth)acrylate, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, isooctyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isodecyl (meth)acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate, isobornyl (meth)acrylate, lauryl (meth)acrylate, It may include at least one selected from the group consisting of 2-hydroxy methyl (meth) acrylate, 2-hydroxy ethyl (meth) acrylate, 2-hydroxy propyl (meth) acrylate, and 2-hydroxy butyl (meth) acrylate.

[0023] Meanwhile, when the glass transition temperature of the acrylic polyol is high, the weight average molecular weight and number average molecular weight of the acrylic polyol are high, so the bonding force between polyols is excellent, and a hard glass state can be maintained even at high temperatures, so the manufactured coating film can secure excellent resistance to external stimuli, such as chemical stimuli. For example, peeling of the coating film due to air freshener or marks left by sunscreen, etc. are problems caused by chemicals penetrating into the bonds between polyols, and when the glass transition temperature of the acrylic polyol is high, it may be difficult for chemicals to penetrate because the bonds between polyols are high. However, if an acrylic polyol with a high glass transition temperature is included alone, the viscosity of the paint is excessively high, resulting in low compatibility with pigments and additives. In addition, compared to polyol resins with similar solid content, the solvent content is low, so the paint dries relatively quickly and dries before a coating film is formed, making it difficult to form a uniform appearance. In addition, the produced coating film can easily break when subjected to physical stimulation, such as force from the outside, due to the hard surface.

[0024] Meanwhile, when the glass transition temperature of acrylic polyol is low, it is in a soft rubber state, so it has excellent flexibility and excellent resistance to physical stimuli applied by external force, and the viscosity of the paint containing it is low, so the spray workability is excellent, and since it has excellent compatibility with pigments and additives, compared to a polyol resin with a similar solid content, the solvent content is high, so a stable film formation time can be secured and a uniform appearance can be formed. However, when the glass transition temperature of acrylic polyol is low, the bonding force between polyols is low, so that chemical substances can easily penetrate, and the manufactured film can be easily broken by external stimuli such as chemical stimuli.

[0025] Accordingly, the present invention can provide a coating film that is excellent in both chemical and physical stimulation properties, such as sunscreen resistance, fragrance resistance, and scratch resistance, by including acrylic polyols having different glass transition temperatures, such as an acrylic polyol resin having a relatively high glass transition temperature and an acrylic polyol resin having a relatively low glass transition temperature.

[0026] Additionally, the hydroxyl value of the acrylic polyol resin is a factor that affects the remaining unreacted monomer in the coating, which can affect the chemical resistance of the resulting coating. Furthermore, the weight-average molecular weight of the acrylic polyol resin is a factor that affects the attractive force between the primer layer and the base layer, which can affect the adhesiveness of the resulting coating.

[0027] Accordingly, the present invention can provide a coating film having excellent chemical resistance, scratch resistance, and adhesion, such as sunscreen resistance and fragrance resistance, by including two or more types of acrylic polyol resins having different glass transition temperatures, hydroxyl values, and weight average molecular weights.

[0028]

[0029] 1st acrylic polyol

[0030] The first acrylic polyol controls the viscosity of the composition, thereby improving workability. Furthermore, as described above, the first acrylic polyol has the lowest glass transition temperature among the three acrylic polyols, thereby improving the flexibility of the resulting coating, thereby preventing breakage due to external forces.

[0031] The above first acrylic polyol may be synthesized by polymerizing the acrylic monomer and vinyl monomer as described above according to a known method, or a commercially available product may be used.

[0032] The glass transition temperature (Tg) of the first acrylic polyol may be -10°C to 10°C, or -5°C to 5°C. When the glass transition temperature of the first acrylic polyol satisfies the above range, the manufactured coating film has an excellent workability effect. On the other hand, when the glass transition temperature of the first acrylic polyol is below the above range, the overall glass transition temperature of the manufactured coating film decreases, resulting in a problem of reduced chemical resistance due to a decrease in resistance to air fresheners or sunscreens, and when it exceeds the above range, a problem of reduced workability of a composition including the same may occur.

[0033] In addition, the first acrylic polyol may have a hydroxyl value (OHv) of 140 to 160 mgKOH / g, or 145 to 155 mgKOH / g. When the hydroxyl value of the first acrylic polyol satisfies the above range, crosslinking with the curing agent is easily formed, thereby preventing moisture penetration, thereby improving the moisture resistance of the manufactured coating film. That is, when the hydroxyl value of the first acrylic polyol is 140 mgKOH / g or more, the degree of crosslinking is prevented from decreasing during the manufacture of the coating film, thereby suppressing the overall deterioration of physical properties, and when the hydroxyl value of the first acrylic polyol is 155 mgKOH / g or less, the curing speed is controlled, thereby preventing the residue of unreacted monomers having low molecular weight, thereby preventing the weakening of intermolecular bonds, thereby suppressing the penetration of chemicals, thereby improving the deterioration of the chemical resistance of the manufactured coating film.

[0034] Meanwhile, the weight average molecular weight (Mw) of the first acrylic polyol may be 13,000 to 18,000 g / mol, or 14,500 to 17,000 g / mol. When the weight average molecular weight of the first acrylic polyol satisfies the above range, a coating film having excellent adhesion can be secured. On the other hand, when the weight average molecular weight of the first acrylic polyol is less than 13,000 g / mol, the amount of resin is insufficient to form a coating film, which may cause a problem in that the adhesion of the manufactured coating film is reduced, and when it exceeds the above range, the viscosity of the composition increases, which may cause a problem in that the workability of the coating film is reduced.

[0035] In addition, the solid content (NV) of the first acrylic polyol may be 45 to 60 wt%, or 49 to 55 wt%, based on the total weight of the first acrylic polyol. When the solid content of the first acrylic polyol satisfies the above range, a coating film having an excellent appearance can be produced. On the other hand, when the solid content of the first acrylic polyol is less than the above range, there is a problem that the paintability of the coating film is reduced and the coating film is not formed, and when the solid content (NV) exceeds 60 wt%, the viscosity of the composition increases, which may cause a problem that the painting workability is reduced.

[0036] Meanwhile, the first acrylic polyol may be included in an amount of 10 wt% to 30 wt%, or 15 wt% to 25 wt%, and specifically, 18 wt% to 22 wt%, based on the total weight of the base paint composition. When the content of the first acrylic polyol satisfies the above range, a coating film having excellent chemical resistance can be produced. That is, when the content of the first acrylic polyol is 10 wt% or more, curing crosslinking increases, thereby improving the chemical resistance of the produced coating film, and when the content of the first acrylic polyol is 30 wt% or less, excellent adhesion of the coating film can be secured.

[0037]

[0038] Second acrylic polyol

[0039] The second acrylic polyol is a component that improves the degree of crosslinking of the base paint composition to improve the chemical resistance and long-term adhesion such as heat resistance and light resistance of the manufactured coating film. As described above, among the three types of acrylic polyols, it has the highest glass transition temperature, so it can improve the chemical resistance of the manufactured coating film and play a role in preventing damage caused by external chemical stimuli.

[0040] The above second acrylic polyol may be synthesized by directly polymerizing the acrylic monomer and vinyl monomer as described above according to a known method, or a commercially available product may be used.

[0041] The second acrylic polyol may have a glass transition temperature (Tg) of 80 to 110° C., or 90 to 105° C. When the glass transition temperature of the second acrylic polyol satisfies the above range, the manufactured coating film has excellent resistance to air fresheners and / or sunscreens, thereby ensuring excellent chemical resistance. On the other hand, when the glass transition temperature of the second acrylic polyol is below the above range, the bond between polyols becomes weak, which facilitates penetration of chemicals, resulting in a problem of reduced chemical resistance of the manufactured coating film. When the glass transition temperature exceeds the above range, the solvent may evaporate easily, which may result in a problem of reduced painting workability of a composition containing the same.

[0042] In addition, the second acrylic polyol may have a hydroxyl value (OHv) of 5 to 25 mgKOH / g, or 10 to 20 mgKOH / g. When the hydroxyl value of the second acrylic polyol satisfies the above range, the manufactured coating film can secure an excellent sunscreen resistance effect. That is, when the hydroxyl value of the second acrylic polyol is 5 mgKOH / g or more, the degree of crosslinking is improved during the manufacture of the coating film, so that the physical properties of the manufactured coating film can be improved, and when the hydroxyl value of the second acrylic polyol is less than 25 mgKOH / g, the composition can be prevented from being cured before the coating film is properly formed, so that a stable coating film with improved physical properties can be formed.

[0043] The second acrylic polyol may have a weight average molecular weight (Mw) of 20,000 to 33,000 g / mol, or 24,500 to 29,500 g / mol. When the weight average molecular weight of the second acrylic polyol satisfies the above range, a coating film having an excellent appearance can be formed. On the other hand, when the weight average molecular weight of the second acrylic polyol is less than the above range, there is a problem that the appearance of the manufactured coating film is deteriorated, and when it exceeds the above range, mixing is difficult during the manufacture of a paint containing it due to high viscosity, so that productivity is reduced, and even when a paint containing it is produced, a problem may arise in which spray coating workability is insufficient due to high viscosity.

[0044] In addition, the solid content (NV) of the second acrylic polyol may be 40 to 50 wt%, or 44 to 46 wt%, based on the total weight of the second acrylic polyol. When the solid content of the second acrylic polyol satisfies the above range, excellent painting workability can be secured. On the other hand, when the solid content of the second acrylic polyol is less than the above range, there is a problem that the paintability is reduced, making it difficult to appropriately control the film thickness, and when it exceeds the above range, there may be a problem that the painting workability of the composition is reduced.

[0045] The second acrylic polyol may be included in an amount of 10 to 30 wt%, 13 to 23 wt%, and specifically 15 to 20 wt%, based on the total weight of the base paint composition. When the content of the second acrylic polyol satisfies the above range, a coating film having excellent long-term adhesion can be formed. When the content of the second acrylic polyol is less than the above range, the long-term adhesion properties such as heat resistance and light resistance of the manufactured coating film may deteriorate, and when it exceeds the above range, the workability of the composition may deteriorate.

[0046]

[0047] 3rd acrylic polyol

[0048] The third acrylic polyol plays a role in improving the adhesion, sun resistance and hardness of the manufactured coating film.

[0049] In addition, the third acrylic polyol may be synthesized by directly polymerizing the acrylic monomer and vinyl monomer as described above according to a known method, or a commercially available product may be used.

[0050] The third acrylic polyol may have a glass transition temperature (Tg) of 40 to 60°C, or 45 to 55°C. When the glass transition temperature of the third acrylic polyol satisfies the above range, a coating film having an excellent appearance can be produced. On the other hand, when the glass transition temperature of the third acrylic polyol is less than 40°C, there is a problem that the chemical resistance of the produced coating film is lowered, and when the glass transition temperature exceeds 60°C, the painting workability of the composition may be lowered or the compatibility of the composition may be lowered.

[0051] In addition, the third acrylic polyol may have a hydroxyl value (OHv) of 5 to 20 mgKOH / g, or 7 to 13 mgKOH / g. When the hydroxyl value of the third acrylic polyol satisfies the above range, the crosslinking density is increased, thereby improving the strength of the manufactured coating film, thereby forming a coating film having excellent mechanical properties. On the other hand, when the hydroxyl value of the third acrylic polyol is less than the above range, there is a problem that the crosslinking degree of the coating film is reduced, and when it exceeds the above range, there may be a problem that the coating film is not cured.

[0052] The weight average molecular weight (Mw) of the third acrylic polyol may be 20,000 to 28,000 g / mol, or 25,000 to 28,000 g / mol. When the weight average molecular weight of the third acrylic polyol satisfies the above range, the adhesiveness of the manufactured coating film is excellent. On the other hand, when the weight average molecular weight of the third acrylic polyol is less than the above range, the intermolecular force with the primer layer is reduced, which may cause a problem of insufficient adhesiveness of the manufactured coating film, and when it exceeds the above range, the high viscosity of the paint containing it may cause a problem of insufficient painting workability during spray painting.

[0053] In addition, the solid content (NV) of the third acrylic polyol may be 40 to 50 wt%, or 44 to 46 wt%, based on the total weight of the third acrylic polyol. When the solid content of the third acrylic polyol satisfies the above range, a coating film having excellent sunscreen resistance can be formed. On the other hand, when the solid content of the third acrylic polyol is less than the above range, there is a problem of reduced paintability during the production of the coating film, and when it exceeds the above range, there may be a problem of reduced compatibility and painting workability of the coating composition.

[0054] The third acrylic polyol may be included in an amount of 1 wt% to 15 wt%, or 5 wt% to 10 wt%, and specifically 6 wt% to 8 wt%, based on the total weight of the base paint composition. When the content of the third acrylic polyol satisfies the above range, a coating film having excellent sun resistance and hardness can be formed. When the content of the third acrylic polyol is less than the above range, the sun resistance of the manufactured coating film is lowered, and when it exceeds the above range, the painting workability of the paint composition may be lowered or the fragrance resistance of the manufactured coating film may be lowered.

[0055]

[0056] Meanwhile, in the base paint composition of the present invention, the first acrylic polyol and the third acrylic polyol may be included in a weight ratio of 2.0:1 to 3.7:1, and more specifically, the first acrylic polyol and the third acrylic polyol may be included in a weight ratio of 2.1:1 to 3.5:1.

[0057] At this time, if the weight ratio of the first acrylic polyol to the weight of the third acrylic polyol is less than the above range, that is, if a small amount of the first acrylic polyol of less than 2.0 weight ratio is included, there is a problem that the workability of the composition and / or the flexibility of the manufactured coating film is reduced, and if it exceeds the above range, that is, if an excessive amount of the first acrylic polyol exceeding 3.7 weight ratio is included, there may be a problem that the adhesion of the manufactured coating film is reduced.

[0058] Additionally, the second acrylic polyol and the third acrylic polyol may be included in a weight ratio of 1.5:1 to 3.2:1, or may be included in a weight ratio of 1.6:1 to 3.0:1, and specifically may be included in a weight ratio of 1.6:1 to 2.7:1.

[0059] When the weight of the second acrylic polyol relative to the weight of the third acrylic polyol is less than the above range, that is, when a small amount of the second acrylic polyol of less than 1.6 weight ratio is included, there is a problem that the chemical resistance of the manufactured coating film is lowered, and when it exceeds the above range, that is, when an excessive amount of the second acrylic polyol exceeding 3.0 weight ratio is included, there may be a problem that the painting workability of the composition is lowered.

[0060]

[0061] Isocyanate curing agent

[0062] The above isocyanate-based curing agent reacts with the hydroxyl group of the first acrylic polyol, the second acrylic polyol, and / or the third acrylic polyol to form a urethane bond, thereby curing the paint composition and forming a coating film.

[0063] In addition, the type of the isocyanate-based curing agent is not particularly limited as long as it can be applied as a curing agent to a urethane-based paint composition, and examples thereof include hexamethylene diisocyanate, toluene diisocyanate, xylene diisocyanate, polymers or modified forms thereof, etc.

[0064] The above isocyanate-based curing agent may have an isocyanate group (NCO) content (NCO%) of 17 to 27 wt%, or 20 to 24 wt%, based on the total weight of the isocyanate-based curing agent. If the NCO% of the isocyanate-based curing agent is less than the above range, the crosslinking density of the produced coating film may decrease, which may cause problems such as lowering the impact resistance, water resistance, and cold chipping resistance of the coating film. If it exceeds the above range, the curing speed may increase and the curing agent may aggregate, which may cause lowering of the appearance characteristics, gloss, and mechanical properties of the coating film.

[0065] In addition, the weight average molecular weight (Mw) of the isocyanate-based curing agent may be 1,000 to 2,500 g / mol, or 1,500 to 2,100 g / mol. When the weight average molecular weight of the isocyanate-based curing agent satisfies the above range, the produced coating film has excellent smoothness and has the effect of forming a soft coating film. On the other hand, when the weight average molecular weight of the isocyanate-based curing agent is outside the above range, the problem of the coating film not being cured may occur.

[0066]

[0067] solvent

[0068] The above solvent serves to control the thickness of the coating film and improve the coating workability of the composition.

[0069] At this time, the solvent may include at least one selected from the group consisting of non-polar solvents and polar solvents. The non-polar solvents include, for example, n-heptane and n-hexane, and the polar solvents include, for example, ethyl acetate, n-butyl acetate, isobutyl acetate, ethylene glycol monoethyl ether acetate, 3-methoxy butyl acetate, amyl acetate, butylene glycol acetate, methyl ethyl ketone, methyl isobutyl ketone, acetone, diisobutyl ketone, isophorone, and cyclohexanone. Specifically, the solvent may include an ester solvent and a ketone solvent.

[0070] In addition, there is no particular limitation on the amount of the solvent used, but if the solvent is used in excessive amounts, problems such as reduced adhesion of the paint composition or reduced paintability due to reduced viscosity may occur, and if too little is used, it is difficult to expect the effect from the use of the solvent. For example, the solvent may be included in the composition in an amount of 20 to 60 wt%, or 35 to 55 wt%, based on the total weight of the base paint composition.

[0071]

[0072] additives

[0073] The above base paint composition may additionally include one or more additives selected from the group consisting of pigments, curing time delay agents, surface conditioners, curing accelerators, and matting agents.

[0074] The above pigment serves to control the color of the exterior of the coating film, and is not particularly limited as long as it can be applied to paint in general, and examples thereof include carbon black, copper phthalocyanine, ferric trioxide, nickel, 5,5-azobis-2,4,6(1H,3H,5H)-pyrimidinetrione complex, titanium dioxide, etc.

[0075] The above pot life delaying agent plays a role in controlling the pot life of the paint composition, and is not particularly limited as long as it can be applied to paint in general, and examples thereof include glycol di(3-mercaptopropionate) (GDMP).

[0076] The above surface conditioner plays a role in controlling the surface tension of the manufactured coating film, and is not particularly limited as long as it can be applied to paint, and for example, a siloxane-based surface conditioner or a non-silicone-based surface conditioner can be used.

[0077] The above curing accelerator serves to increase the crosslinking density of the paint. As the above curing accelerator, those generally used in paint compositions to increase the degree of crosslinking can be used, and examples thereof include metal compounds such as dibutyltin diacetate, dibutyltin dilaurate, stannic octate, and dibutyltin mercaptide; tertiary amines such as triethyldiamine, triethanolamine, 1,4-diazocyclooctane, dimethylethanolamine, ethylmorpholine, dimethylaminoethylmorpholine, and dimethylcyclohexylamine; and carboxylates or zinc-based complexes of alkali metals.

[0078] The above matting agent serves to control the gloss of the manufactured coating. The matting agent is not particularly limited as long as it is a conventional one that can be used in a paint composition, and examples thereof include silica-based ones.

[0079]

[0080] two-component type

[0081] The above base paint composition may be a two-component paint including a main component and a hardener component, and may be used after mixing the main component and the hardener component prior to application. For example, the above base paint composition may be a two-component paint including a main component including a first acrylic polyol, a second acrylic polyol, a third acrylic polyol, and a solvent; and a hardener component including an isocyanate-based hardener and a solvent.

[0082] At this time, the base paint composition may include the main body and the hardener in a weight ratio of 1:0.5 to 1:2.0, or a weight ratio of 1:0.9 to 1:1.2.

[0083] The base paint composition according to the present invention, as described above, has excellent painting workability and excellent adhesion to plastic materials. In addition, a coating film prepared from the base paint composition has excellent various physical properties such as chemical resistance, fragrance resistance, sunscreen resistance, heat resistance, and light resistance, and thus the base paint composition is highly suitable as a base paint for plastic materials such as automobile interior parts, and particularly for plastics.

[0084]

[0085] Hereinafter, the present invention will be described in more detail through examples. However, these examples are provided solely to aid understanding of the present invention and are not intended to limit the scope of the present invention in any way.

[0086] [Example]

[0087] Examples 1 to 13 and Comparative Examples 1 to 6. Preparation of base paint composition

[0088] The main component was manufactured using each component in the composition as described in Tables 1 to 3 below.

[0089] Thereafter, a base paint composition was prepared by mixing the hydroxyl group of the above-mentioned subject matter and the isocyanate group of hexamethylene diisocyanate trimer (HDI Trimer), which is an isocyanate curing agent, in an equivalent ratio of 1:1.

[0090] Ingredients (parts by weight) Example 1 2 3 4 5 6 7 1-1 Acrylic polyol 2 1 2 1 2 1 2 1 2 1 2 1 1-2 Acrylic polyol 2 1 1-3 Acrylic polyol 2 1 2-1 Acrylic polyol 1 6 1 6 1 6 1 2-2 Acrylic polyol 1 6 2-3 Acrylic polyol 1 6 3-1 Acrylic polyol 7.5 7.5 7.5 7.5 7.5 3-2 Acrylic polyol 7.5 3-3 Acrylic polyol 7.5 Pigment 3 3 3 3 3 3 Additive 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 1.3 Matting agent 6.2 6.2 6.2 6.2 6.2 6.2 6.2 6.2 6.2 Solvent 4 5 4 5 4 5 4 5 4 5 4 5 Total 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0

[0091]

[0092] Ingredients (weight parts) Example 89 10 11 12 13 1-1 Acrylic polyol 15 2 5 2 12 12 1 1-2 Acrylic polyol 1-3 Acrylic polyol 2-1 Acrylic polyol 16 16 13 2 3 16 16 2-2 Acrylic polyol 2-3 Acrylic polyol 3-1 Acrylic polyol 7.5 7.5 7.5 7.5 6 10 3-2 Acrylic polyol 3-3 Acrylic polyol Pigment 33 33 3 Additive 1.3 1.3 1.3 1.3 1.3 1.3 1.3 Matting agent 6.2 6.2 6.2 6.2 6.2 6.2 6.2 Solvent 5 14 14 8 3 8 4 6.5 4 2.5 Total 100 100 100 100 100

[0093]

[0094] Ingredients (weight parts) Comparative example 123456 1-1 Acrylic polyol 21 212121 1-4 Acrylic polyol 21 1-5 Acrylic polyol 21 2-1 Acrylic polyol 16 16 16 16 2-4 Acrylic polyol 16 2-5 Acrylic polyol 16 3-1 Acrylic polyol 7.5 7.5 7.5 7.5 3-4 Acrylic polyol 7.5 3-5 Acrylic polyol 7.5 Pigment 3.0 3.0 3.0 3.0 3.0 3.0 Additive 1.3 1.3 1.3 1.3 1.3 1.3 1.3 Matting agent 6.2 6.2 6.2 6.2 6.2 6.2 6.2 Solvent 4.5 4.5 4.5 4.5 Total amount 100 100 100 100 100 100

[0095]

[0096] Below, the manufacturers and product names of each component used in the examples and comparative examples are shown in Table 4 below. Here, NV is the solid content, OHv is the hydroxyl value, Tg is the glass transition temperature, and Mw is the weight average molecular weight.

[0097] Ingredients Manufacturer and Product Name Remarks 1-1 Acrylic polyol-NV: 50 wt%, OHv: 150 mgKOH / g, Tg: 0 ℃, Mw: 16,100 g / mol 1-2 Acrylic polyol-NV: 52 wt%, OHv: 147 mgKOH / g, Tg: -5 ℃, Mw: 14,500 g / mol 1-3 Acrylic polyol-NV: 49 wt%, OHv: 153 mgKOH / g, Tg: 5 ℃, Mw: 17,000 g / mol 1-4 Acrylic polyol-NV: 45 wt%, OHv: 140 mgKOH / g, Tg: -12 ℃, Mw: 18,000 g / mol 1-5 Acrylic polyol-NV: 55 wt%, OHv: 160 mgKOH / g, Tg: 13℃, Mw: 13,000 g / mol 2-1 Acrylic polyol-NV: 45 wt%, OHv: 15mgKOH / g, Tg: 100℃, Mw: 27,000 g / mol 2-2 Acrylic polyol NV: 44 wt%, OHv: 10mgKOH / g, Tg: 90℃, Mw: 29,500 g / mol 2-3 Acrylic polyol NV: 46 wt%, OHv: 20mgKOH / g, Tg: 105℃, Mw: 24,500 g / mol 2-4 Acrylic polyol-NV: 40 wt%, OHv: 5mgKOH / g, Tg: 75℃, Mw: 33,000 g / mol 2-5 Acrylic polyol-NV: 50 wt%, OHv: 25mgKOH / g, Tg: 115℃, Mw: 20,000 g / mol 3-1 Acrylic polyol-NV: 45 wt%, OHv: 10mgKOH / g, Tg: 50℃, Mw: 26,500 g / mol 3-2 Acrylic polyol NV: 45 wt%, OHv: 7mgKOH / g, Tg: 45℃, Mw: 28,000 g / mol 3-3 Acrylic polyol NV: 45 wt%, OHv: 13mgKOH / g, Tg: 55℃, Mw: 25,000 g / mol 3-4 Acrylic polyol-NV: 45 wt%, OHv: 5mgKOH / g, Tg: 35℃, Mw: 35,000 g / mol 3-5 Acrylic polyol-NV: 45 wt%, OHv: 25mgKOH / g, Tg: 65℃, Mw: 20,000 g / mol Pigment Carbon Black AdditivesCuring time retardant:Surface conditioner:Curing accelerator = 7:1:5 in weight ratioCuring time retardant: CHIOCURE GDMP (THIOCHEMICALS), Surface conditioner: Borchi Gol OL17 (OMG BORCHERS GMBH GERMANY), Curing accelerator: SONGSTAB TL-100 (SONGWON)Matting agentManufacturer: PQ coporation, Product name: Gasil HP-33Amorphous silica solvent-a mixture of butyl acetate, methyl isobutyl ketone and ethyl acetate in a weight ratio of 1:1.6:0.2,

[0098]

[0099] Test Example: Evaluation of the properties of manufactured coatings

[0100] Each base paint composition (dry film thickness: 13±1㎛) prepared in the examples and comparative examples was applied onto polypropylene, a plastic material, and then cured with hot air at 80℃ for 30 minutes to obtain a film. Thereafter, the physical properties of the film were measured using the following method, and the results are shown in Table 5.

[0101] (1) Adhesiveness

[0102] The adhesion of the coating was measured by cutting 100 squares (1 mm wide × 1 mm long) horizontally and vertically with a blade and removing them using tape according to the ASTM D3359 tape adhesion test method.

[0103] At this time, if 100 squares were 100% completely attached, it was evaluated as excellent (◎), if the remaining squares were 95% or more but less than 100%, it was evaluated as good (○), if they were 90% or more but less than 95%, it was evaluated as average (△), and if they were less than 90%, it was evaluated as poor (×).

[0104] (2) Sunscreen properties

[0105] Two sheets of cotton cloth (equivalent to Toyosynthetic CH2070-3) of the same size were overlapped 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. After that, the area where the sunscreen was applied was placed on the coating 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 the acrylic plate were removed, and left at room temperature for 10 minutes. After that, the coating was washed with a neutral detergent, dried, and the adhesion of the coating was evaluated. The evaluation criteria were the same as those for the above item (1).

[0106] (3) Inner air freshener

[0107] An aluminum cap with a diameter of 20 mm was attached to the surface of the coating film using an adhesive (Manufacturer: VITAL TECHNICAL, Product Name: Rapid 3-Tone Epoxy Adhesive), and 0.2 ml of a fragrance evaluation solution (a solution of isoamyl acetate: limonene: linalool = 4:1:1 by volume) was dropped inside the aluminum cap using a dropper and left at room temperature for 5 minutes. After leaving it in a constant temperature bath at 70±2℃ for 30 minutes, it was taken out, the attached aluminum cap was removed, and the surface of the coating film was visually inspected.

[0108] As a result of the test, if there were no visible wrinkles on the coating and no wrinkles when touched by hand, it was evaluated as excellent (◎); if there were no visible wrinkles but wrinkles were formed when touched by hand, it was evaluated as good (○); if there were visible fine wrinkles, it was evaluated as average (△); and if there were very severe wrinkles when touched by hand, it was evaluated as poor (x).

[0109] (4) Acetone resistance

[0110] Acetone resistance was evaluated by rubbing the final coating 10 times with a 500g load on a cloth soaked in isobutanol, ethanol, and methanol, respectively. As a result of the test, if the coating did not peel or discolor, it was evaluated as excellent (◎), if the coating did not peel and was grade 4 on the GREY SCALE, it was evaluated as good (○), if the coating did not peel and was grade 3 on the GREY SCALE, it was evaluated as average (△), and if the coating peeled or was grade 2 or lower on the GREY SCALE, it was evaluated as poor (×).

[0111] (5) Heat resistance

[0112] After immersing the coating in a 40℃ constant temperature bath for 10 days, the adhesion of the coating was evaluated using the same method and criteria as in item (1) above.

[0113] (6) Light resistance

[0114] After exposing the coating film to 1,050 kJ of energy for 2 hours using a xenon weatherometer tester, it was evaluated using the same method and criteria as in item (1) above.

[0115] (7) Appearance

[0116] The appearance of the manufactured coating was evaluated by measuring the size of defects such as scratches, pinholes, foreign matter, and unevenness on the surface. If there were two or fewer defects on the coating surface that were less than 0.3 cm in size, it was evaluated as excellent, and otherwise, it was evaluated as poor.

[0117] (8) Scratch resistance

[0118] The scratch resistance was evaluated by scratching the coating film once with a scraper weighing 0.5 kg to determine the degree of surface damage. At this time, if the final coating film showed no surface damage, it was evaluated as excellent (◎), if there was slight damage, it was evaluated as good (○), if the surface damage was somewhat noticeable but not severe, it was evaluated as average (△), and if the surface damage was noticeable and significantly noticeable, it was evaluated as poor (×).

[0119] (9) Moisture resistance

[0120] After immersing the coating in a constant temperature bath at 40℃ for 10 days, the adhesion of the coating was evaluated, and the evaluation method and criteria for adhesion were applied in the same manner as in item (1) above.

[0121] AdhesivenessSunscreen resistanceFragrance resistanceAcetone resistanceHeat resistanceLight resistanceExterior resistanceScratch resistanceMoisture resistanceExample 1◎◎◎◎◎◎◎◎◎2◎○○○◎◎◎◎3◎◎◎◎◎◎◎4◎○○○◎◎◎◎5◎◎◎◎◎◎○○◎6◎○○○◎◎◎◎7◎◎◎◎◎◎◎◎8◎○○○◎◎◎◎◎9○◎◎◎◎◎◎◎10◎○○◎○○◎◎◎11◎◎◎◎◎◎◎○○◎12◎○○○◎◎◎◎◎13◎◎◎◎◎◎○○◎Comparative Example 1○△△△○○○○○2○○○○○○△△○3○△△△○○○○○4○○○○○○△△○5○△△△○○○○○6○○○○○○△△○

[0122]

[0123] Referring to Table 5, it can be seen that the coating films prepared from the base paint compositions of Examples 1 to 13 are excellent in adhesion, sunscreen resistance, fragrance resistance, acetone resistance, heat resistance, light resistance, appearance characteristics, scratch resistance, and moisture resistance.

[0124] On the other hand, it can be seen that the coating films prepared from the base paint compositions of Comparative Examples 1 and 2 including the first acrylic polyol having a glass transition temperature outside the scope of the present invention, the coating films prepared from the base paint compositions of Comparative Examples 3 and 4 including the second acrylic polyol having a glass transition temperature outside the scope of the present invention, and the coating films prepared from the base paint compositions of Comparative Examples 5 and 6 including the third acrylic polyol having a glass transition temperature outside the scope of the present invention are inferior to the coating films prepared from the base paint compositions of Examples 1 to 13 in terms of sunscreen resistance, fragrance resistance, acetone resistance, and appearance properties.

Claims

1. Containing a first acrylic polyol, a second acrylic polyol, a third acrylic polyol, an isocyanate curing agent and a solvent, The above first acrylic polyol has a glass transition temperature of -10°C to 10°C, The above second acrylic polyol has a glass transition temperature of 80°C to 110°C, The above third acrylic polyol is a base paint composition for plastic having a glass transition temperature of 40°C to 60°C.

2. In claim 1, The above first acrylic polyol has a hydroxyl value of 140 mgKOH / g to 160 mgKOH / g, The second acrylic polyol has a hydroxyl value of 5 mgKOH / g to 25 mgKOH / g, The third acrylic polyol is a base paint composition for plastic having a hydroxyl value of 5 mgKOH / g to 20 mgKOH / g.

3. In claim 1, A base paint composition for plastic, wherein the first acrylic polyol has a weight average molecular weight of 13,000 g / mol to 18,000 g / mol, the second acrylic polyol has a weight average molecular weight of 20,000 g / mol to 33,000 g / mol, and the third acrylic polyol has a weight average molecular weight of 20,000 g / mol to 28,000 g / mol.

4. In claim 1, A base paint composition for plastic comprising the first acrylic polyol, the second acrylic polyol, and the third acrylic polyol in a weight ratio of 2.0:1.5:1 to 3.7:3.2:

1.

5. In claim 1, The base paint composition for plastic comprises 10 to 30 wt% of a first acrylic polyol, 10 to 30 wt% of a second acrylic polyol, and 1 to 15 wt% of a third acrylic polyol, based on the total weight of the base paint composition for plastic.