KR20090073469A - Polyester resin comprising isobede and paint containing same - Google Patents

Abstract

Disclosed is a thermosetting polyester resin containing isobe and a coating material comprising the same, capable of forming a coating film having excellent hardness and workability. The said polyester resin is a polyacid component containing 80 mol% or more of aromatic diacid components with respect to the whole polyacid component; And a polyhydric alcohol component including 60 to 95 mole% of aliphatic dihydric alcohol and 5 to 40 mole% of an sorbide compound represented by the following formula with respect to the entire polyalcohol component.

In addition, the paint is 10 to 60% by weight of the polyester resin; And the remaining solvents.

Description

Polyester resin including isopide and paint containing same {Polyester resin including isorbide and paint composition including the same}

The present invention relates to a polyester resin and a coating material comprising the same, and more particularly, to a thermosetting polyester resin including isobe, which can form a coating film excellent in both hardness and processability, and a coating material containing the same. .

PCM (Pre-Coated Metal) steel plate for home appliances requires excellent workability and hardness compared to steel plates for building materials. However, workability and hardness are mutually opposite physical properties, and at the same time, it is difficult to satisfy them. Therefore, research on paints capable of forming a coating film having excellent hardness while having workability necessary for low temperature processing has been continuously conducted. Commonly used PCM steel plate paints for home appliances include polyester resins as base resins, melamine resins or isocyanate compounds as crosslinking agents, and other small amounts of additives such as curing catalysts, antifoaming agents and leveling agents. As the polyester resin for paints, a linear polyester resin having a low glass transition temperature (Tg) is mainly used in order to prevent cracking during processing of the steel sheet and to improve workability. However, when the linear polyester resin is used, the workability of the coating film is good, but since the hardness of the coating film is low, the surface of the coating film is easily damaged due to the contact between the steel sheets or a mistake of the user when processing, transporting or using the steel sheets. have. In order to solve this problem, a method of attaching a protective film to the coating film is also used after the production of the PCM steel sheet, but not only an additional cost is required to attach the protective film, but also the coating film is damaged when the protective film is removed and the product is used. The problem still exists.

In order to solve this problem, a method of improving the hardness of the coating film has been developed using a branched polyester resin having a high glass transition temperature. For example, a method is known in which a linear polyester resin having a hydroxyl value of 40 to 90 mgKOH / g and a polyester resin in a branch form are mixed and a butylated melamine resin or an isocyanate resin is used as a crosslinking agent. In addition, in order to impart hardness, processability and non-pollution property, a methyl etherated melamine resin or a butyl ether melamine resin having an amino group or a methoxy group is mixed and a method of using a sulfonic acid compound and an amine compound as a curing catalyst is also known. . However, in the above methods, the hardness of the coating film is increased, but the ductility is lowered, so that cracks are likely to occur in the coating film during forming / processing of the steel sheet, and when the steel sheet is exposed to contact with moisture, the steel sheet is corroded, and the painting work It is difficult to obtain a smooth appearance at the time.

The coating composition for improving this is disclosed by Unexamined-Japanese-Patent No. 4-145176, 10-152645, 8-127752, US Pat. In the above patents, it is disclosed that by using butoxy melamine and methoxy melamine in combination, a PCM coating having excellent hardness, processability, stain resistance and the like of the coating film can be obtained. However, in the methods disclosed in the above patents, since the degree of crosslinking of melamine increases, not only the processing properties are limited, but also there is a limit in increasing the hardness, so that it is difficult to obtain satisfactory physical properties. In addition, Japanese Patent Application Laid-Open No. 08-196991 discloses a coated steel sheet excellent in workability and stain resistance, and Japanese Patent Application Laid-Open No. 09-241582 discloses a coating composition for PCM. It is disclosed that the hardness, fouling resistance and chemical resistance of a coating film can be improved by using PET resin and acrylic resin as a melamine or urethane crosslinking agent. However, PET resins used as main resins in the above patents have limited solvent compatibility and poor compatibility with various paint additives, which makes it difficult to apply practically since a uniform appearance cannot be obtained during coating work. In addition, there is a disadvantage that the workability is insufficient to use as a home appliance. In order to solve this problem, reducing the addition amount of the pigment, there is a problem that the coating is poor.

Therefore, to date, branch polyester resins are used for PCM steel sheets requiring severe bending and processing, including linear polyester resins as main resins, and using paints with excellent processability, and for steel sheets with low processing / molding degree such as refrigerators. It is a situation to selectively use a coating material having only one of the physical properties of the coating film, such as using a coating material with excellent hardness, such as the hardness and processability of the coating film, if necessary.

Therefore, the objective of this invention is providing the polyester resin which can form the coating film excellent in hardness and workability, and the coating material containing this.

Another object of the present invention is to provide a thermosetting polyester resin and a paint containing the same, which can form a coating film having excellent scratch resistance and gloss, and are particularly useful as a coating material for pre-coated metal (PCM) coating. It is.

In order to achieve the above object, the present invention, a polyaddition component comprising an aromatic diacid component of 80 mol% or more relative to the entire polyacid component; And a polyhydric alcohol component comprising 60 to 95 mole% of an aliphatic dihydric alcohol and 5 to 40 mole% of an sorbide compound represented by the following Chemical Formula 1 with respect to the entire polyalcohol component: To provide.

[Formula 1]

In addition, the present invention is 10 to 50% by weight of the polyester resin; And it provides a coating composition comprising the remaining solvent.

The polyester resin and the coating material comprising the same according to the present invention can form a coating film excellent in both hardness and workability. Since the paint according to the present invention forms a coating film excellent in hardness and scratch resistance, it is useful as an industrial paint for interior and exterior painting of buildings, PCM (pre-coated metal) paint, and can coating.

Hereinafter, the present invention will be described in detail.

The paint according to the invention is 10 to 60% by weight, preferably 20 to 50% by weight of the polyester resin and the remaining content, preferably 40 to 90% by weight, more preferably 35 to the total coating composition. To 71 wt%, most preferably 44 to 64 wt% of the solvent. In addition, the paint according to the present invention, 3 to 13% by weight of the crosslinking agent, 0.1 to 1.5% by weight of the curing catalyst, 0.3 to 10% by weight of the slip additive, 0.5 to 1.0% by weight of the leveling agent , 0.5 to 1.0 wt% antifoaming agent, 10 to 40 wt% pigment, and the like may be further included. Hereinafter, each component of the paint according to the present invention will be described item by item.

1. Polyester Resin

The polyester resin which concerns on this invention consists of a condensation reaction of a polyacid component and a polyhydric alcohol component. The polyacid component which comprises the polyester resin of this invention contains an aromatic diacid component and an aliphatic diacid component as needed. As said aromatic diacid component, lower (C1-C4) alkyl ester compounds, such as terephthalic acid, isophthalic acid, phthalic anhydride, these monomethyl, monoethyl, dimethyl, or diethyl ester, a mixture thereof, etc. are mentioned. It can be illustrated. The content of the aromatic diacid component is 80 mol% or more, preferably 80 to 99.9 mol%, more preferably 90 to 98 mol% with respect to the entire polyacid component. Here, when the content of the aromatic diacid component is less than 80 mol%, the glass transition temperature (Tg) of the polyester resin is too low, there is a fear that the hardness of the coating film is insufficient. In addition, as the aliphatic diacid component, a linear or branched aliphatic dibasic acid may be used, and non-limiting examples thereof include sebacic acid, succinic acid, maleic acid, fumaric acid, adipic acid, azelaic acid, and the like. Aliphatic dibasic acids, these lower (C1-C4) alkyl ester compounds, these acid anhydrides, etc. can be illustrated. The aliphatic diacid component serves to improve processability and workability of the polyester resin, and is 20 mol% or less, for example, 0.1 to 20 mol%, preferably 1 to 10 mol%, based on the total polyacid component. Can be used as In addition, if necessary, trivalent or higher polyvalent acid components such as pyromellitic acid may be further used, and the amount of use thereof is 10 mol% or less, for example, 1 to 10 mol% based on the total polyacid components.

The polyhydric alcohol component constituting the polyester resin of the present invention includes an aliphatic dihydric alcohol and an sorbide compound represented by the following general formula (1), and an aromatic diol component as necessary. It may further include.

As the aliphatic dihydric alcohol, ethylene glycol, propylene glycol, neopentyl glycol, methyl propanediol, 1,4-butylene glycol, 1,3-butylene glycol, 2,3-butylene glycol, 1,6- C1-C10 aliphatic (including alicyclic) diols such as cyclohexanedimethanol, such as hexanediol and 1,4-cyclohexanedimethanol, and mixtures thereof, may be used, and the aromatic diol ) As the component, ethylene oxide (EO) addition bisphenol A, propylene oxide (PO) addition bisphenol A, mixtures thereof, and the like (wherein, the added mole number of ethylene oxide, propylene oxide, etc. is preferably 2 to 4 mol, and 2-3 Mole is more preferable). The aliphatic dihydric alcohol component improves the workability and workability of the polyester resin, and the isobeide (Isorbide) compound increases the glass transition temperature (Tg) of the polyester resin, To improve hardness, the aromatic diol (diol) component serves to simultaneously increase the hardness and workability by introducing an epoxy resin at the end of the polyester resin.

In the polyhydric alcohol component used in the production of the polyester resin of the present invention, the content of the aliphatic dihydric alcohol is 60 to 95 mol%, preferably 70 to 85 mol% with respect to the entire polyhydric alcohol component, The content of the Isorbide compound is 5 to 40 mol%, preferably 10 to 30 mol% with respect to the entire polyalcohol component. When the aromatic diol component is used, the content is the total polyhydric alcohol. It is 10 mol% or less with respect to a component, for example, 1-10 mol%. Here, when the content of the aliphatic dihydric alcohol is too small, there is a problem that the workability is lowered, and when too large, there is a problem that the hardness of the coating film formed of the polyester resin is lowered. In addition, when the content of the above-mentioned Isorbide compound is too small, there is a problem that the hardness of the coating film formed of the polyester resin is lowered, and when too large, there is a problem that the workability is lowered. Moreover, as needed, the polyhydric alcohol component used for manufacture of the polyester resin of this invention can contain a glycol compound or a trivalent or more polyhydric alcohol further. Examples of the glycol compound or the trihydric or higher polyhydric alcohol may include diethylene glycol, dipropylene glycol, pentaerythritol, mixtures thereof, and the like, and the amount thereof is 0 to the entire polyhydric alcohol component. 10 mol%, preferably 1-10 mol%.

The polyester resin according to the present invention, like conventional polyester resins, can be prepared in two stages: esterification reaction or transesterification reaction, and polycondensation reaction. The esterification reaction is carried out by direct condensation reaction between the polyacid component and the polyhydric alcohol component in the presence of a conventional polycondensation catalyst, and the transesterification reaction is carried out with dialkyl dicarboxylates (eg, dimethyl terephthalate, Bis (2-hydroxyethyl) terephthalate and the like) and the diol component. Here, the molar ratio of the total alcohol component used amount (G) to the total acid component used amount (A) is preferably 1.0 to 2.0, more preferably 1.2 to 1.8. If the ratio (G / A) is less than 1.0, unreacted acid components may remain, leading to a decrease in transparency of the resin. If the ratio (G / A) is above 2.0, the polymerization reaction rate may be too slow to reduce productivity of the resin. .

The number average molecular weight (Mn) of the thermosetting polyester resin for PCM paints according to the present invention is 8,000 to 20,000, the hydroxyl value is 5 to 20 mgKOH / g, the acid value is 1 to 5 mgKOH / g, and the glass transition temperature (Tg) is preferably 35 to 80 ℃. Herein, when the number average molecular weight (Mn) is out of the range, there is a concern that the physical properties of the coating film may be lowered, and when the hydroxyl value and the acid value are too high, appearance defects and popping may occur due to rapid hardening at high temperature. There is a concern, but this can be solved by using a high boiling point solvent appropriately. In addition, when the glass transition temperature is too high, the workability of the coating film is lowered, and when too low, there is a fear that the coating film hardness is lowered. In the coating composition according to the present invention, the content of the polyester resin is 10 to 50% by weight, preferably 15 to 45% by weight, if the content of the polyester resin is too small, the hardness of the paint falls, too If there is much, there exists a possibility that the workability of paint may fall.

2. Crosslinking agent

A crosslinking agent forms a coating film with the said polyester resin component, Preferably melamine resin can be used, The isocyanate resin is not preferable because a yellowing phenomenon may generate | occur | produce in the hardening method of high temperature baking. The melamine resin includes a melamine resin containing an amino group or a butoxy group and a melamine resin containing a methoxy group. Melamine resins containing amino or butoxy groups are advantageous for increasing the hardness of the coating film. However, when acid catalysts are used, the melamine resin has a disadvantage in that the reaction temperature is slightly slower than the methoxy melamine resin and the workability is lowered. On the other hand, when methoxy melamine resin is used with an acid catalyst, the curing reaction rate is high and the processability of the coating film is excellent, but the hardness of the coating film is relatively poor. Therefore, in this invention, in order to maintain the balance of the hardness and workability of a coating film, the said amino type or butoxy type melamine resin and the methoxy type melamine resin are mixed and used by the weight ratio of 0.3: 1-0.5: 1. It is preferable. At this time, when the mixing ratio of the two melamine resins is less than 0.3: 1, the workability of the coating film is good, but there is a disadvantage in that the surface hardness is lowered. There are disadvantages. In the present invention, 2 to 8% by weight of a methyl etherified melamine resin having a methoxy group is used, and 1 to 5% by weight of a melamine resin having an amino group or a butoxy group, and the curing agent is 3 to 13 based on the total coating composition. It is contained in the weight% range. Examples of the methoxy type melamine resin include CYTEC's CYMEL303, CYMEL 301, BIP's BE 3747, BE 3745, and MONSANTO's RESIMENE 745. Examples of amino or butoxy type melamine resins include CYTEC's CYMEL 325, CYMEL327, BIP's BE3748, BE 3040, and Monsanto's RESIMENE 717.

3. Curing catalyst

Examples of the curing catalyst included in the coating composition of the present invention include sulfonic acids such as p-toluene sulfonic acid (p-TSA), dinonylnaphthalene sulfonic acid (DNNSA), dinaphthalene disulfonic acid (DNNDSA), and fluoro sulfonic acid as amine or epoxy. Neutralized can be used. The amine and the epoxy are added for the reaction shielding of the catalyst, and as the amine, primary amine, secondary amine, tertiary amine and the like can be used. In general, it is preferable to use a secondary amine because the primary amine causes a color change such as yellowing in the coating film, and the tertiary amine causes shrinkage of the surface of the coating film when used in excess. Examples of the secondary amines include diethylamine, diisopropylamine, diisopropanolamine, di-n-propylamine, di-n-butylamine, isobutylamine, di-secondary-butylamine, diallylamine, Diamylamine, N-ethyl-1,2-dimethylpropylamine, N-methylhexylamine, di-n-octylamine, piperidine, 2-pipecoline, 3-piecholine, 4-piecoline, Morpholine and the like, and by adding these effective amounts to the coating composition, the fouling resistance of the coating film can be increased. If a catalyst not neutralized with amine or epoxy is used, the viscosity increases after storage of the paint or the physical properties of the coating film are poor. Commercially available examples of the p-toluene sulfonic acid include King's NACURE2500, NACURE2510, NACURE 2530, and the like. Low sulfonic acid includes FC520 of 3M (3M), etc. In addition, p-toluene sulfonic acid neutralized with tertiary amine, dinonyl naphthalene sulfonic acid (DNNSA), etc. can be used as an auxiliary curing catalyst. The curing catalyst is contained in the range of 0.1 to 1.5% by weight based on the total coating composition.

4. Solvent

The coating composition of the present invention contains an appropriate amount of an organic solvent in consideration of characteristics during handling, coating and the like. As the organic solvent, it is possible to disperse the polyester resin and other components and can be easily removed, and can be used without limitation, aromatic hydrocarbon-based, glycol ester-based, glycol ether-based, alcohol-based solvents, etc. are used by mixing appropriately It is desirable to. The aromatic hydrocarbon solvents include Cocosol # 100, Cocosol # 150, etc. of SK Energy Co., Ltd., and glycol ester solvents include ethyl acetate, n-butyl acetate, cellosolve acetate, propylene glycol monomethyl acetate, 3- Methoxybutyl acetate and the like. Glycol ether solvents include methyl cellosolve, ethyl cellosolve, ethylene glycol butyl ether, diethylene glycol methyl ether, diethylene glycol ethyl ether, diethylene glycol butyl ether, and alcohol solvents such as ethanol, isopropanol, n -Butanol, amyl alcohol, cyclohexanol, etc. are mentioned. The solvent comprises the remaining components of the total coating composition, preferably 30 to 90% by weight, more preferably 35 to 71% by weight, most preferably 44 to 64% by weight. If the amount of the solvent used is too small, there is a fear that the adhesion of the coating film is lowered. If the amount of the solvent is too large, there is a disadvantage that a long time is required for drying.

5. Other additives

The slip additive that may be included in the coating composition of the present invention is to prevent scratches caused by scratches by workers during the forming of steel sheets or nails of users of home appliances, and may be polyethylene (PE) wax or polytetrafluorocarbons. Low ethylene (PTFE) wax, PTFE / PE mixed wax and the like can be used. It is preferable that the usage-amount of the said polyethylene-type wax is 3 to 5 weight% with respect to the whole coating composition, and when it is less than the said range, there exists a possibility that sufficient slip property may not be provided to a coating film, and when it exceeds the said range, the glossiness of a coating film This may fall. When PTFE-based wax is used, the PTFE itself has excellent hardness, but the specific gravity of PTFE is higher than that of the resin, the orientation of the coating to the surface during curing is slow, the melting point of PTFE is high, the coating appearance becomes rough, and the slip (SLIP) performance There is a problem that is not manifested well. Therefore, a mixed wax of PTFE and PE is most preferable. The reason is that PE wax has excellent surface orientation, but has a poor slip effect, and PTFE has a good slip effect, but has problems in surface orientation. It is because the use of the wax which combined these is preferable. These PTFE / PE waxes must be made of two materials through a high-speed disperser, in which a PTFE wax is attached around a low density PE wax, i.e. the PTFE wax is electrostatically charged around a PE particle with a large particle size. It is a product combined into. Although the hardness of the coating film using such a mixed wax can obtain sufficient slipability without deteriorating the excellent coating film hardness, it is preferable to have a particle size of 3 μm or less because the appearance of the coating film is poor when the PTFE / PE wax particles are too large. . Since the gloss of the coating film is lowered when the wax is used excessively, it is preferable to use 0.3 to 10% by weight based on the total coating composition. Examples of the wax products include MPI-31 and F-600XF of Micro Powder, Ceraflour 995 and 996 of BYK, SL-524 and SL-409 of Daniel Products. There is this. On the other hand, when the conventional silicone oils are used as slip additives, the surface tension of the silicone oils is too low, the continuous roll coating workability is poor, it is not preferable. In addition, it is appropriate to use an additive of 0.1 to 1% by weight of the clay-based, amide wax-based, fume silica-based additives to improve the workability, any of these may be used.

In addition, in order to maintain the coating film smoothness and to improve the defoaming property during painting, it is preferable to use an acrylic, vinyl or silicone leveling agent and an antifoaming agent at 0.5 to 1.0% by weight, respectively. Examples of the leveling agent and the antifoaming agent include Disparon L-1980, Disparon L-1984, Disparon AP-30, BYK356 by BYK356, BYK410, etc. of Kusumoto Chemical. In addition, although the coating composition of the present invention can be used as a transparent coating composition containing no pigment, it is generally used as a coating composition containing a coloring pigment. Color pigments include organic color pigments such as cyanine blue, cyanine green, and any color pigments usable in the field of coating compositions, and inorganic color pigments such as titanium oxide, iron oxide, carbon black, chrome yellow and various plastic pigments. In addition, the coating composition of the present invention may include a sieving pigment such as talc, clay, silica, mica, alumina, filler, and the like. The pigment is contained in the range of 10 to 40% by weight based on the total coating composition. When there is too much quantity of the said pigment, the adhesiveness of a dry coating film, the dispersibility of a pigment, etc. will worsen.

Hereinafter, the present invention will be described in more detail with reference to specific examples and comparative examples. The following examples are intended to illustrate the present invention more specifically, but the present invention is not limited by the following examples.

[Examples 1-5, Comparative Examples 1-2] Production of Polyester Resin

In a 2 L reactor equipped with a stirrer and an outlet condenser, reactants (molar ratio of alcohol component to acid component, G / A = 1.0 to 1.5) of components and contents as shown in Table 1 below were used as catalysts, TiO ₂ / SiO _2. Filled with coprecipitation. At this time, the amount of catalyst used was 200 ppm relative to the acid component. Under the nitrogen stream, the temperature of the reactor was gradually raised to 250 ° C, and the esterification reaction was performed while leaving byproduct water and methanol out of the reactor. After the generation and outflow of the water and methanol were complete, the reaction was transferred to a polycondensation reactor equipped with a stirrer, a cooling condenser and a vacuum system. After adding 200 ppm of trimethyl phosphate as a heat stabilizer, the reaction temperature was raised to 250 ° C, and the excess diol component was allowed to flow out while reacting under low vacuum while reducing the reaction pressure to 50 mmHg over 30 minutes. Next, the reaction pressure was gradually reduced to 0.1 mmHg, and under high vacuum, the polymerization reaction was performed until a predetermined stirring torque appeared. In Table 1, the content unit of each component is a mole part, TPA is terephthalic acid, IPA isophthalic acid, AA is adipic acid, SA is sebacic acid, and NDC is naphthalenedicarboxylate. EG represents ethylene glycol, NPG represents neopentyl glycol, HD represents 1,6-hexanediol, and BPA-EO represents ethylene oxide (EO) addition bisphenol A.

Ingredients (mol) Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 TPA 25 20 20 25 25 25 20 IPA 25 20 20 25 25 25 20 AA 10 SA 10 NDC 10 EG 15 10 10 5 25 20 25 NPG 25 25 25 25 25 20 25 HD 10 15 Isorbide 10 10 15 10 10 BPA-EO 5 10 IV 0.6 0.6 0.6 0.6 0.6 0.6 0.6 Tg 74 76 79 70 65 70 75

As described above, when the coating composition according to the present invention is used in a PCM steel sheet, it is possible to obtain a coating film having excellent hardness and scratch resistance while maintaining workability equivalent to that of a conventional coating material, regardless of season and temperature during painting. Excellent appearance can be obtained.

[Examples 6-10 and Comparative Examples 3-4] Preparation of Paint and Test of Coating Properties

As shown in Table 2 below, thermosetting PCM paints were prepared using the polyester resins obtained in Examples 1 to 5 and Comparative Examples 1 and 2, respectively.

Raw material name (unit: parts by weight) Example 6 Example 7 Example 8 Example 9 Example 10 Comparative Example 3 Comparative Example 4 Resin (parts by weight) Example 1 Resin, 30 parts by weight Example 2 Resin, 30 parts by weight Example 3 Resin, 30 parts by weight Example 4 Resin, 30 parts by weight Example 5 Resin, 30 parts by weight Comparative Example 1 Resin, 30 parts by weight Comparative Example 2 Resin, 30 parts by weight TiO2 10 10 10 10 10 10 10 Strontium Chromate 10 10 10 10 10 10 10 Dispersant 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Melamine curing agent 3.0 3.0 3.0 3.0 3.0 3.0 3.0 Acid catalyst 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Antifoam 0.5 0.5 0.5 0.5 0.5 0.5 0.5 menstruum 46 46 46 46 46 46 46 Sum 100 100 100 100 100 100 100

In Table 2, the dispersant is EFKA-4050 (Switzerland, EFKA company name), the melamine curing agent Cymel-325 (USA, Cymel-325, Cytec industry), the acid catalyst Nacure-5225 (USA, KING EFKA-2021 (Swiss, EFKA brand name), Cocosol-100 (K-100) or Cocosol-150 (K-150) (Korea, SK Energy) .

In addition, in order to confirm the coating properties of the paint, the coating was coated on the zinc phosphate-treated steel sheet, the thickness of the coated coating film was 5 ± 2㎛, the surface temperature of the steel plate was 240 ℃. In addition, the top coat was formed of a thermosetting polyester resin having a hydroxyl group% of 0.5 to 1%, a number average molecular weight of 12,000, and a Tg (glass transition temperature) of 30 ° C. As a coating property test method, (1) processability was measured according to National Coil Coaters Association (NCAA) -II-19, and (2) pencil hardness was measured according to NCAA-II-12. The results thus measured are shown in Table 3 below.

Example 6 Example 7 Example 8 Example 9 Example 10 Comparative Example 3 Comparative Example 4 Machinability (0T) 0 ~ 1T 0 ~ 1T 1 ~ 2T 0 ~ 1T 0 ~ 1T 1 ~ 2T 1 ~ 2T Pencil hardness 1H 1H 3H 2H 2H 1H 1H

From Table 3, it can be seen that when using the PM coating material according to the present invention (Examples 6 and 10), compared with the coating composition of Comparative Examples 3 and 4, the processability and hardness is improved.

Claims (6)

A polyacid component containing at least 80 mol% of an aromatic diacid component with respect to the entire polyacid component; And A polyester resin, comprising a polyhydric alcohol component comprising 60 to 95 mol% of an aliphatic dihydric alcohol and 5 to 40 mol% of an sorbide compound represented by the following formula (1) with respect to the entire polyhydric alcohol component. [Formula 1]

The polyester resin according to claim 1, wherein the polyacid component comprises 80 to 99.8 mole percent of an aromatic diacid component and 0.2 to 20 mole percent of an aliphatic diacid component. The method of claim 2, wherein the aromatic diacid component is selected from the group consisting of terephthalic acid, isophthalic acid, phthalic anhydride, alkyl ester compounds thereof, and mixtures thereof, and the aliphatic diacid component is sebacic acid, succinic acid. , Maleic acid, fumaric acid, adipic acid, azelaic acid, alkyl ester compounds thereof, acid anhydrides thereof, and mixtures thereof. The method of claim 1, wherein the aliphatic dihydric alcohol is ethylene glycol, propylene glycol, neopentyl glycol, methyl propanediol, 1, 4- butylene glycol, 1, 3- butylene glycol, 2, 3- butylene glycol , 1,6-hexanediol, cyclohexane dimethanol, and mixtures thereof. The method according to claim 1, wherein the polyester resin has a number average molecular weight (Mn) of 8,000 to 20,000, a hydroxyl value of 5 to 20 mgKOH / g, an acid value of 1 to 5 mgKOH / g, and a glass transition temperature (Tg). Is 35 to 80 ℃, polyester resin. A polyacid component containing at least 80 mol% of an aromatic diacid component with respect to the entire polyacid component; And 60 to 95 mole% of aliphatic dihydric alcohol and 5 to 40 mole% of chemical formula with respect to the entire polyalcohol component

10 to 60% by weight of a polyester resin comprising a polyhydric alcohol component containing an isosorbide compound represented by; And Coating composition containing the remaining solvent.