KR102121813B1 - Coating composition - Google Patents

Abstract

The present invention relates to a coating composition comprising an acrylic polyol resin containing a carbamate group, a silane-modified polyrotaxane resin, and a long chain acrylic polyol resin containing a hydroxyl group.

Description

Coating composition {COATING COMPOSITION}

The present invention relates to a coating composition having excellent scratch resistance.

In the automotive coating industry, the top coat may consist of a single layer or a double layer of a base coat and a clear coat. The color tone and transparent coating system that applies a transparent clear coat after applying a base coat that imparts color to the substrate is a finishing process for commonly used automotive coatings, and is capable of withstanding various and strict conditions required for automobiles. Is required.

In the case of the conventional one-component coating composition using a resin containing an hydroxyl group and an amino resin as a resin part, it has been known to provide excellent coating properties, while ether bonding formed by a curing mechanism has poor acid resistance. As one of the methods for solving this problem, a coating composition based on a cured structure having a carbamate functional group has been known in the art. The thermosetting coating composition incorporating a carbamate-cured structure has high transparency and high DOI (phase distinction), as well as improved durability, hardness and flexibility, as well as improved scratch resistance.

U.S. Patent No. 5545211 consists of a carbamate acrylic resin/melamine or a carbamate melamine/oxyzolidine block DDBSA (dodecylbenzyl sulfonic acid) catalyst, and can be applied as a one-part coating composition, and has a hardness, but has flexibility Coating compositions having excellent chemical resistance are disclosed. In addition, U.S. Patent Publication No. 2003-0009052 discloses a coating composition composed of a carbamate-modified acrylic resin, a carbamate-modified polyester, melamine, and a curing agent. Particularly, a lactone and a hydroxyl group are pre-reacted, followed by further reaction with carbamate. It has been disclosed that a carbamate polyester prepared in the form of a can be used as a rheology control agent (RCA) having properties to resist sagging.

However, when the conventional compositions as described above are applied to a one-component transparent coating using a melamine curing agent, there is still a problem that scratches easily occur due to daily washing such as automatic washing or dust removal, stain removal, and the like. Therefore, when applied to a one-component coating composition using a melamine curing agent, there is still a need for research to improve scratch resistance.

US 5474511 B US 2003-0009052 A

The present invention provides a coating composition having excellent scratch resistance.

The present invention provides a coating composition comprising a carbamate group-containing acrylic polyol resin, a silane-modified polyrotaxane resin, and a hydroxyl group-containing long chain acrylic polyol resin.

Although the coating composition according to the present invention is a one-component coating composition using a melamine curing agent, it exhibits excellent scratch resistance compared to the prior art.

Hereinafter, the present invention will be described in detail.

The present invention provides a coating composition.

The coating composition of the present invention includes an acrylic polyol resin containing a carbamate group, a silane-modified polyrotaxane resin, and a long chain acrylic polyol resin containing a hydroxyl group.

The components constituted as described above may be included in a content of 50 to 80 parts by weight based on 100 parts by weight of the total coating composition, and it is difficult to obtain properties such as appearance of coating and desired mechanical properties when the content is outside the above numerical range.

Hereinafter, the components constituting the coating composition will be described in detail.

Acrylic polyol resin containing carbamate group (A)

The carbamate group-containing acrylic polyol resin used in the present invention may serve to improve the appearance and mechanical properties of the coating.

The carbamate group-containing acrylic polyol resin is not limited thereto, and may be produced using, for example, an ethylenically unsaturated monomer, a non-functional acrylic monomer, an acrylic monomer containing a hydroxyl group, and an alkyl carbamate. The ethylenically unsaturated monomer that can be used to prepare the carbamate group-containing acrylic polyol resin may include styrene and derivatives thereof, butadiene and acrylic or methacrylic acid esters of C ₁ to C ₁₂ alkyl, but is not limited thereto.

Non-functional acrylic monomers that can be used to prepare the carbamate group-containing acrylic polyol resin include methyl methacrylate, ethyl methacrylate, isobutyl methacrylate, normal butyl methacrylate, tertiary butyl methacrylate, and normal hexyl Methacrylate, 2-ethylhexyl methacrylate, isobornyl methacrylate, cyclohexyl methacrylate, methyl acrylate, ethyl acrylate, propyl acrylate, isobutyl acrylate, normal butyl acrylate, tertiary butyl acrylic Late, 2-ethylhexyl acrylate, normal octyl acrylate, isobornyl acrylate and cyclohexyl acrylate may be used, but are not particularly limited as long as they do not adversely affect the acrylic polyol resin.

The acrylic monomer containing a hydroxyl group that can be used to prepare the carbamate group-containing acrylic polyol resin is 2-hydroxyethyl methacrylate, hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-hydroxy Ethyl acrylate, 2-hydroxypropyl acrylate, kaduraacrylate, kaduramethacrylate, caprolactone acrylate, caprolactone methacrylate, 2,3-dihydroxypropylacrylic, 2,3-dihydroxypropyl Methacrylate, polypropylene-modified acrylate, polypropylene-modified methacrylate, 4-hydroxymethylcyclohexyl-methylacrylate, 4-hydroxymethylcyclo-methylmethacrylate, 2,2,4-trimethyl -1,3-pentaneol monoacrylate, 2,2,4-trimethyl-1,3-pentaneol monomethacrylate, isobornyl acrylate, isobornylmethacrylate, and the like.

In addition, the alkyl carbamate which can be used to prepare the acrylic polyol resin containing the carbamate group is methyl carbamate, ethyl carbamate, n-procarbamate, isopropyl carbamate, n-butyl carbamate, isobutyl carbamate, tert-butyl carbamate, n-hexyl carbamate, 2-ethylhexyl carbamate, cyclohexyl carbamate, phenyl carbamate, hydroxypropyl carbamate, and hydroxyethyl carbamate, but is not limited thereto.

The carbamate group-containing acrylic polyol resin may be prepared by radical polymerization of the ethylenically unsaturated monomer, a non-functional acrylic monomer, an acrylic monomer containing a hydroxyl group, and an alkyl carbamate in an organic solvent.

The organic solvent is not particularly limited as long as it does not adversely affect the polymerization reaction of the carbamate group-containing acrylic polyol resin, for example, aromatic hydrocarbon solvents such as toluene, xylene, cocosol #100, #150, methyl ethyl ketone , Ester solvents such as methyl propyl ketone, methyl butyl ketone, ethyl propyl ketone, esters such as methyl acetate, ethyl acetate, n-propyl acetate, n-butyl acetate, ethyl ethoxypropionate, n-butanol, Alcohol-based solvents such as propanol and 1-methoxy2-propanol can be used.

A molecular weight modifier and a radical polymerization initiator may be used in the radical polymerization reaction. The molecular weight modifier may be, for example, one or more selected from the group consisting of mercaptans such as n-dodecyl mercaptan, n-decyl mercaptan, t-dodecyl mercaptan, and alpha methyl styrene dimer. Further, the radical polymerization initiator may be, for example, 2,2'-azobis(2-methylbutylonitrile), 2,2'-azobisisobutylonitrile, dibenzoyl peroxide, or tertiarybutylperoxy benzoate , Tertiary butyl peroxide, tertiary butyl peroxy-2-ethyl hexanoate, tertiary butyl peroxy acetate, tertiary mill peroxy-2-ethyl hexanoate, diteria mill peroxide, cumyl hydroperoxide , Dicumyl peroxide, and the like.

The carbamate group-containing acrylic polyol resin may have a weight average molecular weight of 3,000 to 10,000, a glass transition temperature of -30°C to 30°C, and a hydroxyl value of 30 to 70 mgKOH/g based on solid content weight. When the weight average molecular weight, glass transition temperature and hydroxyl value in the carbamate group-containing acrylic polyol resin do not satisfy the above range, there is a problem that scratch resistance of the finally produced coating film cannot be obtained. In addition, the carbamate-containing acrylic polyol resin may have an equivalent weight of 400 to 800 carbamate groups based on solid content weight, for example, 500 to 700. When the equivalent weight of the carbamate group is less than 400, a problem may occur in which the appearance decreases due to an increase in polarity, and when it exceeds 800, a problem in which chemical resistance deteriorates due to a lack of a reactor may occur.

The carbamate group-containing acrylic polyol resin may be included in an amount of 20 to 60 parts by weight, for example, 30 to 50 parts by weight based on 100 parts by weight of the total coating composition. If the content of the carbamate group-containing acrylic polyol resin is less than 20 parts by weight, a problem that chemical properties such as chemical resistance may be inhibited, and when it exceeds 60 parts by weight, a problem such as excessive chipping resistance and excessive hardening of the coating film may occur. Can be. In addition, if it is outside the above numerical range content, mechanical properties and workability during manufacturing and painting may be particularly deteriorated.

Silane-modified polyrotaxane resin (B)

The silane-modified polyrotaxane resin used in the present invention may serve to improve the scratch resistance of the coating film formed with the carbamate group-containing acrylic polyol resin.

The silane-modified polyrotaxane resin is a silane group introduced into a polyrotaxane resin.

The polyrotaxane refers to a molecule in which at least one ring-shaped molecule penetrates a dumbbell-shaped axial molecule, which is a straight chain molecule having a bulky block group at both ends. That is, polyrotaxane is a compound having a form in which a plurality of ring-shaped molecules penetrate one straight-chain molecule. The cyclic molecule of the polyrotaxane is capable of freely moving on the straight-chain molecule, but is characterized by having a structure that cannot escape from the straight-chain molecule by a block group. It has a structure that maintains shape by bonding. Due to the above characteristics, since polyrotaxane has high mobility of cyclic molecules, it may have an effect of relaxing stress from the outside or stress remaining inside.

The straight chain molecule is not particularly limited as long as it is a molecule that penetrates through the opening of the cyclic molecule and has a functional group capable of reacting with the block group. For example, polyalkylene glycols such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol, polybutadienediol, polyisoprenediol, polyisobutylenediol, poly(acrylonitrile-butadiene)diol, hydrogenated poly Terminal hydroxyl group polyolefins such as butadiene diol, polyethylene diol, polypropylene diol, polycaprolactone diol, polylactic acid, polyethylene adipate, polybutylene adipate, polyethylene terephthalate, polyesters such as polybutylene terephthalate, terminal Terminal functional polysiloxanes such as silanol type polydimethylsiloxane, terminal amino group polyethylene glycol, terminal amino group polypropylene glycol, terminal amino group polybutadiene, and other terminal amino group chain polymers and three or more functional groups having three or more of the above functional groups in one molecule It may be a polyfunctional chain polymers, but is not limited thereto.

In addition, the said cyclic molecule|numerator is not specifically limited if a straight chain molecule can penetrate an opening part. For example, cyclodextrins, crown ethers, cryptands, macrocyclic amines, calix arenes, cyclopanes, and the like can be mentioned. Cyclodextrins are compounds in which a plurality of glucoses are cyclically formed by α-1,4-linkage, and may be α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin, or the like.

When the cyclodextrin of the present invention is included as a cyclic molecule in polyrotaxane, the hydroxyl group contained in the glucose constituting the cyclodextrin may be modified with at least one silyl group. For example, the hydroxyl group of the cyclotextrin may be modified by an isocyanate containing an silyl group and an isocyanate-alcohol reaction. For example, the silyl group included in the isocyanate is trimethylsilyl group, triethylsilyl group, t-butyldimethylsilyl group, vinyldimethylsilyl group, propyldimethylsilyl group, triphenylsilyl group, diphenylsilyl group or phenylsilyl group , Triethoxysilyl group, and the like.

For example, the polyrotaxane resin of the present invention may be a necklace-type molecule in which α-cyclodextrin modified with triethoxysilyl isocyanate is a silane-modified ring-shaped molecule, and which is a straight-chain molecule, polyethylene glycol. The silane-modified polyrotaxane resin may have a weight average molecular weight of 35,000 to 45,000, a glass transition temperature of 70°C to 80°C, and a silyl group of 35 to 70 mg THF based on solid content weight. When the silane-modified polyrotaxane resin is outside the above range, excellent scratch resistance cannot be exhibited.

The silane-modified polyrotaxane resin may be included in an amount of 2 to 25 parts by weight, for example, 10 to 15 parts by weight based on 100 parts by weight of the total coating composition. When the content of the silane-modified polyrotaxane resin is less than 2 parts by weight, the excellent effect of elasticity, flexibility and scratch resistance of the coating film cannot be exhibited, and when it is included in excess of 25 parts by weight, a problem in that glossiness may be deteriorated may occur.

Long-chain acrylic polyol resin containing hydroxyl group (C)

The hydroxyl group-containing long-chain acrylic polyol resin used in the present invention may serve to improve gloss and image clarity of a coating film together with the carbamate group-containing acrylic polyol resin.

The hydroxyl group-containing long-chain acrylic polyol resin can be prepared using an ethylenically unsaturated monomer, a non-functional acrylic monomer, a hydroxyl group-containing long-chain polymerizable monomer, and the like, and the above-described monomers are used in organic solvents such as molecular weight modifiers, radical polymerization initiators, and the like. It can be prepared by radical polymerization using.

The organic solvent, radical polymerization initiator, ethylenically unsaturated monomer, and non-functional acrylic monomer are the same as those described in the carbamate group-containing acrylic polyol resin, so a detailed description thereof will be omitted.

The hydroxyl group-containing long chain polymerizable monomer for producing the hydroxyl group-containing long chain acrylic polyol resin may have a chemical structure represented by the following Chemical Formula 1.

[Formula 1]

In Chemical Formula 1, R ₁ may be hydrogen, an alkyl group having 1 to 10 carbon atoms, and R ₁ is any one selected from the group consisting of hydrogen or an alkyl group having 1 to 6 carbon atoms and a cycloalkyl group having 5 to 7 carbon atoms. May be, R _{1 It} may be any one selected from the group consisting of hydrogen and an alkyl group having 1 to 4 carbon atoms.

In Formula 1, R ₂ may be any one selected from the group consisting of an alkyl group having 1 to 40 carbon atoms or a cycloalkyl group having 3 to 40 carbon atoms, and R ₂ is an alkyl group having 2 to 20 carbon atoms and 5 to 30 carbon atoms. It may be any one selected from the group consisting of cycloalkyl groups. The alkyl group or cycloalkyl group may be straight or branched chain, and methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, sec-butyl, 1-methylbutyl, 1-ethylbutyl, n -Pentyl, isopentyl, neopentyl, tert-pentyl, n-hexyl, 1-methylpentyl, 2-methylpentyl, 4-methyl-2-pentyl, 3,3-dimethylbutyl, 2-ethylbutyl, n-heptyl , 1-methylhexyl, cyclopentylmethyl, cyclohexylmethyl, n-octyl, tert-octyl, 1-methylheptyl, 2-ethylhexyl, 2-propylpentyl, n-nonyl, 2,2-dimethylheptyl, 1- Ethylpropyl, 1,1-dimethylpropyl, isohexyl, 4-methylhexyl, 5-methylhexyl, and the like, but is not limited thereto.

In addition, in Chemical Formula 1, n may be an integer from 1 to 20, and n may be an integer from 1 to 10 and an integer from 1 to 5.

The hydroxyl group-containing long-chain polymerizable monomer for preparing the hydroxyl group-containing long-chain acrylic polyol resin may be, for example, a polyalkylene glycol mono(meth)acrylate monomer, but is not limited thereto.

The hydroxyl group-containing long-chain acrylic polyol resin has a solids content of 50 to 80% by weight, and a hydroxyl value of 80 to 170 mgKOH/g based on the solids weight. As described above, when the hydroxyl value is less than 80 mgKOH/g and more than 170 mgKOH/g, the elasticity of the coating film cannot be secured. In addition, the hydroxyl group-containing long-chain acrylic polyol resin may have a weight average molecular weight of 10,000 to 30,000, and a glass transition temperature of -50°C to 0°C. When the above numerical range is satisfied, elasticity and scratch resistance of the coating film can be secured.

The hydroxyl group-containing long-chain acrylic polyol resin may be included in an amount of 5 to 25 parts by weight, for example, 10 to 20 parts by weight based on 100 parts by weight of the total coating composition. When the content of the hydroxyl group-containing long-chain acrylic polyol resin is less than 5 parts by weight, the effect of improving the elasticity, flexibility and scratch resistance of the coating film cannot be exhibited, and when it is included in excess of 25 parts by weight, it may be difficult to secure the hardness of the coating film.

Hardener (D)

The coating composition may further include a curing agent.

The curing agent may be a melamine compound, for example, hexamethylolmelamine, hexamethoxymethylmelamine, hexabutoxymethylmelamine, or the like.

The curing agent may be included in a content of 6 to 25 parts by weight, for example, 12 to 18 parts by weight based on 100 parts by weight of the total coating composition. When the content of the curing agent is less than 6 parts by weight, when the curing agent and the components of the coating composition react, incomplete curing may occur, which may affect hardness and solvent resistance, and when it is contained in excess of 25 parts by weight, adhesion due to overcuring Not only can it affect the properties of the coating film, such as sex and impact resistance, it can also adversely affect other properties by remaining unreacted melamine compound in the coating film.

Other ingredients (E)

The coating composition may further include a curing catalyst, an organic solvent and an additive.

The curing catalyst is to accelerate the curing of the components of the coating composition by a curing agent, for example, dodecylbenzenesulfonic acid, sulfonic acid, dinonylnaphthalene disulfonic acid, dinonyl naphthalenesulfonic acid, etc. may be used.

The organic solvent is not particularly limited, and for example, cocosol #100, butanol, 1-methoxy-2-propyl acetate, ethyl ethoxypropionate, and mixtures thereof may be used.

The additive may be used as a surface modifier, light stabilizer, weathering additive, appearance control agent, antifoaming agent, leveling agent, and the like.

The coating composition of the present invention having the above components may have a solid content of 40 to 70% by weight, and the viscosity may satisfy 18 to 50 seconds based on pot cup #4 at 25°C. The viscosity is a viscosity range suitable for coating workability, and if it is lower than 18 seconds, problems such as dripping on a vertical surface may occur, and if it exceeds 50 seconds, a load may be applied to the sprayer and cause a breaker failure, and high viscosity Due to this, it is possible to induce inhibition in the appearance of the painted object.

The coating composition of the present invention as described above may be provided as a one-part coating. In the case of a one-component coating, it is possible to solve problems such as the hassle of mixing two liquid substances generated in the two-component coating and the time required for curing.

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

However, these examples are only for understanding the present invention, and the scope of the present invention is not limited to these examples in any sense.

Example

Synthesis Example 1: Preparation of acrylic polyol resin (A) containing carbamate group

215 parts by weight of Cocosol #100 was inserted into a synthetic four-necked flask equipped with a thermometer, stirrer, condenser, and heating equipment, and heated to a reflux temperature of 165°C. After the reflux is stable, 206 parts by weight of 2-hydroxyethyl acrylate, 190 parts by weight of styrene monomer, 100 parts by weight of normal butyl acrylate, and 40 parts by weight of alphamethylstyrene timer are uniformly mixed, and tertiary butyl peroxybenzoate 15 Part by weight, 40 parts by weight of Cocosol #100 were uniformly mixed separately, and then added and added separately for 180 minutes and 195 minutes, respectively, and maintained at reflux for 60 minutes. After completion of the maintenance, the mixture was diluted with Cocosol #100, the reaction was cooled to 80°C, and 80 parts by weight of methyl carbamate and 1.3 parts by weight of dibutyltin oxide were added, and methanol flowing out at about 145°C was collected separately. When a total of about 30 parts by weight of methanol was collected, nitrogen was injected to remove residual methyl carbamate for 1 hour, followed by cooling to terminate the reaction.

Through the above process, 63% of solid content, viscosity Z2, hydroxyl value of 50 mgKOH/g, weight average molecular weight of 5,000, glass transition temperature of 10°C, carbamate group equivalent is 600, based on solid content weight, acrylic polyol containing carbamate group Resin (A) was obtained.

Comparative Synthesis Example 1: Preparation of acrylic polyol resin (A-1)

215 parts by weight of Cocosol #100 was inserted into a synthetic four-necked flask equipped with a thermometer, stirrer, condenser, and heating equipment, and heated to a reflux temperature of 165°C. After the reflux is stabilized, 203 parts by weight of hydroxypropyl acrylate, 152 parts by weight of styrene monomer, 132 parts by weight of normal butyl methacrylate, 127 parts by weight of normal butyl acrylate, and 10 parts by weight of tertiary butyl peroxybenzoate, coco 52 parts by weight of sol #100 was added dropwise evenly for 180 minutes and 195 minutes, and then maintained at reflux for 60 minutes. After completion of the maintenance, the mixture was diluted with Cocosol #100, and the reaction was cooled to 60° C. to obtain an acrylic polyol resin (A-1) having a solid content of 70%.

Synthesis Example 2: Preparation of silane-modified polyrotaxane resin (B)

76 parts by weight of tertiary distilled water was inserted into a synthesis two-necked flask equipped with a thermometer and a stirring device, and the temperature was raised to a reflux temperature of 40°C. After the reflux was stabilized, 10 parts by weight of α-cyclodextrin and 2 parts by weight of polyethylene glycol bisamine were uniformly mixed, and reflux was maintained for 24 hours. After the reaction was recovered as a solid through lyophilization, 70 parts by weight of ethanol was inserted into the two-neck flask for synthesis and heated to a reflux temperature of 60°C. After the reflux was stabilized, 2 parts by weight of dimethoxytriazinyl methylmorpholinium chloride and 2 parts by weight of dityrosine were mixed, and reflux was maintained for 24 hours. After the reaction was cooled to 25° C., unreacted material was removed through dialysis, and solids were recovered through lyophilization. 10 parts by weight of the recovered polyrotaxane was added to 200 parts by weight of dimethyl sulfoxide and heated to a reflux temperature of 40°C. After reflux was stabilized, 120 parts by weight of triethoxysilylpropyl isocyanate was mixed, and reflux was maintained for 24 hours. The reactants were recovered and dimethyl sulfoxide was replaced with tetrahydrofuran to remove unreacted materials. Through the above process, a silyl group-containing polyrotaxane (B) having a solid content of 50 to 80%, a silyl group having a solid content of 35 to 70 mg THF, and a weight average molecular weight of 35,000 to 45,000 was obtained.

Synthesis Example 3: Preparation of hydroxyl group-containing long chain acrylic polyol resin (C)

66 parts by weight of butyl acetate was inserted into a synthetic 4-neck flask equipped with a thermometer and a stirring device, and the temperature was raised to a reflux temperature of about 130°C. After reflux is stabilized, Miramer M100 (caprolactone acrylate, micro-fiber) 141 parts by weight, methyl methacrylate 39 parts by weight, methacrylic acid 2 parts by weight uniformly mixed, benzoyl peroxide 7 parts by weight, butyl acetate 7 parts by weight uniformly mixed Then, the mixture was uniformly separated and added dropwise for 300 minutes, and maintained at reflux for 60 minutes. Diluted with butyl acetate and cooled to 60° C., the reaction product was cooled to 60° C., with a solid content of 63%, a hydroxyl value of 130 mgKOH/g based on solid content, a weight average molecular weight of 22,000, and a hydroxyl chain-containing long chain acrylic polyol resin having a glass transition temperature of −30° C. C) was obtained.

Manufacturing example

Examples 1 and 2, Comparative Examples 1 to 4

The Synthesis Examples 1 to 3 and Comparative Synthesis Example 1 were stirred and mixed at 1500 rpm for 20 minutes or more with the composition shown in Table 1, to prepare a coating composition.

(Unit: weight%) ingredient Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 A resin 43 40 65 - 50 49 A-1 resin - - - 50 - - B resin 12 15 - - - One C resin 10 10 - 15 15 15 Hardener 15 15 15 15 15 15 Curing catalyst One One One One One One Surface adjuster 0.2 0.2 0.2 0.2 0.2 0.2 Light stabilizer 0.5 0.5 0.5 0.5 0.5 0.5 UV absorber 1.1 1.1 1.1 1.1 1.1 1.1 Cocosol #100 12.2 12.2 10.7 10.7 10.7 10.7 Butanol 5 5 6.5 6.5 6.5 6.5 Sum 100 100 100 100 100 100 1) Curing agent: Alkylated melamine (Cymel 1161)
2) Curing catalyst: dodecylbenzenesulfonic acid (Nacure XP 221)
3) Surface modifier: Silicone surfactant (BYK-331 10%sol'n)
4) Light stabilizer: Hindered amine light stabilizer (Tinuvin 123)
5) UV absorber: Tinuvin 384

Experimental Example

Paint coating conditions

In order to measure the properties of the coating film, each of the coating compositions prepared by mixing with the composition of Table 1 was coated under the following conditions.

① Handgun spray was used.

② Nozzle diameter: 1.5 mm, air pressure: 4.5 kgf/㎠ was kept constant.

③ The distance between the nozzle inlet and the specimen was kept constant in the range of 2 to 30 cm and horizontally moved at a constant speed of 40 to 50 cm/sec to be coated.

④ After coating, after baking at 130℃ for 20 minutes, the physical properties (hardness, adhesion, water resistance, acid resistance and scratch resistance) of the coating film were measured.

Method for measuring properties

1. Hardness

Measurement method: Measured by a pencil hardness method. Specifically, 3B, 2B, B, HB, F, H, 2H, 3H hardness was measured without damaging the coating film with each pencil.

The pencil hardness was denoted as 3B, 2B, B, HB, F, H, 2H, and 3H in the order of excellent inferiority.

2. Adhesion

Measurement method: After the finished coating specimen was treated with a heat treatment cycle until the top coat was applied, it was left at room temperature for 24 hours, and the adhesion was measured by a go method of 0.2 mm intervals.

Heat treatment cycle: 150°C 20 minutes, 20 minutes The process of standing at room temperature was repeated 3 times, and as a result, M-1, M-2, M-3, M-4, and M-5 were in order of excellent adhesion. It was denoted as.

3. Water resistance

Measurement method: The specimen was immersed in a constant temperature water bath at 40° C. for 240 hours, then left at room temperature for 1 hour, and then peeling test was performed with the Go board adhesion evaluation to visually observe the appearance of abnormality.

Judgment method: After the test, the appearance should not have softening, whitening, poor gloss, peeling, swelling, discoloration, etc., and there should be no difference between the appearance of the deposited part and the non-deposited part. It evaluated as M-1, M-2, M-3, M-4, and M-5 in the order of inferior in water resistance.

4. Acid resistance

Measurement Method: After 0.2 ml of 0.1 N sulfuric acid was added dropwise to the test piece, the temperature of the gradient oven was set to 35 to 40°C and heated for 150 minutes.

Determination method: The highest temperature at which damage was not caused was determined as the acid resistance temperature by visually confirming the occurrence of etching, staining and swelling on the site of the test piece where the sulfuric acid solution was dropped.

5. Scratch resistance

Measurement method: 10 round trips were performed using Amtec Kistler equipment.

Judgment method: The initial 20 degree gloss of the specimen was measured, and the 20 degree gloss was measured after 10 round trips. The gloss before measurement was divided by the gloss after measurement to calculate gloss retention.

Example Comparative example ingredient One 2 One 2 3 4 Hardness F HB F B F F Adhesion M-1 M-1 M-1 M-1 M-1 M-1 Water resistance M-1 M-1 M-1 M-1 M-1 M-1 Acid resistance 43 ℃ 43 ℃ 43 ℃ 39 ℃ 43 ℃ 43 ℃ Scratch resistance 74% 78% 53% 51% 60% 63%

As shown in Table 2, compared with the case where the acrylic polyol resin (A-1) was included in the coating composition (Comparative Example 2), the case in which the acrylic polyol resin (A) containing a carbamate group was included (Comparative Example 3) Scratchability improved.

Furthermore, in the case of Examples 1 and 2 further comprising a carbamate group-containing acrylic polyol resin and a silane-modified polyrotaxane resin, the scratch resistance was very excellent at 74% and 78%, respectively. On the other hand, in the case of Comparative Example 4 containing a carbamate group-containing acrylic polyol resin, but containing 1% by weight of a silane-modified polyrotaxane resin, the scratch resistance was only 63%.

Through the above results, it can be seen that when the silane-modified polyrotaxane resin is included, it exhibits an excellent effect on scratch resistance.

In the above, the present invention has been described in detail only with respect to the described embodiments, but it is apparent to those skilled in the art that various modifications and variations are possible within the technical scope of the present invention, and it is natural that such modifications and modifications belong to the appended claims.

Claims (6)

Carbamate group-containing acrylic polyol resin, silane-modified polyrotaxane resin and hydroxyl group-containing long-chain acrylic polyol resin,
The silane-modified polyrotaxane resin has a weight average molecular weight of 35,000 to 45,000 coating composition.
The method according to claim 1,
Based on 100 parts by weight of the total coating composition,
The carbamate group-containing acrylic polyol resin is contained in an amount of 20 to 60 parts by weight, the silane-modified polyrotaxane resin is contained in an amount of 2 to 25 parts by weight, and the hydroxyl group-containing long chain acrylic polyol resin is 5 to 25 parts by weight Coating composition included in content.
The method according to claim 1,
The carbamate group-containing acrylic polyol resin has a carbamate group equivalent of 400 to 800 based on solids weight, and has a glass transition temperature of -30°C to 30°C.
The method according to claim 1,
The silane-modified polyrotaxane resin has a glass transition temperature of 70 ℃ to 80 ℃ coating composition.
The method according to claim 1,
The hydroxyl group-containing long-chain acrylic polyol resin has a hydroxyl value of 80 to 170 mgKOH/g based on solids weight, and a glass transition temperature of -50°C to 0°C.
The method according to claim 1,
The coating composition further comprises a melamine-based curing agent.