KR20060075047A - Acryl modified polyester resin and method of preparing the same - Google Patents

Abstract

An acrylic modified polyester resin and a method for producing the same are disclosed. The acrylic modified polyester resin is formed by condensation reaction between a polyhydric alcohol and a polyacid, and an acrylic urethane prepolymer formed by reacting a methacrylic polyol having an structure as shown in formula (I) and an isocyanate compound to a polyester resin intermediate including a hydroxyl group. Is formed by a coupling reaction. Accordingly, by coupling the acrylic urethane prepolymer in which a meta acrylic polyol is modified to a polyester resin intermediate having a hydroxyl group, a coating composition having excellent physical properties having advantages of polyester and acrylic resin can be prepared.

Description

Acrylic modified polyester resin and its manufacturing method {ACRYL MODIFIED POLYESTER RESIN AND METHOD OF PREPARING THE SAME}

The present invention relates to an acrylic modified polyester resin and an acrylic modified polyester resin manufacturing method, and more particularly, to an acrylic modified polyester resin and an acrylic modified polyester resin manufacturing method used as a coating composition for PCM steel sheet for home appliances.

Paints for PCM steel sheets require excellent mechanical, chemical and efficiency. The mechanical properties are workability indicating the degree of flexibility after coating, pencil hardness, which is a property of the coated surface hardness, adhesion to the base material or top coat, and friction resistance, and the like, and the chemical properties include acid resistance, alkali resistance, solvent resistance and weather resistance. The efficiency is workability such as productivity and cost depending on the work speed.

Generally, PCM (Pre-Coated Metal; hereinafter referred to as "PCM"). As a coating material for steel sheet, acrylic, urethane, epoxy, polyester, silicone, fluorine and polyvinyl chloride resins are used, Various modified and combined resins were used. Most of the paint having the resin as a composition is a thermosetting paint used in admixture with a curing agent.

Japanese Unexamined Patent Publication Nos. 08-196991 and 09-241582 disclose coating compositions excellent in workability. The coating composition improves coating film hardness by using a PET resin or an acrylic resin as a main component and a melamine or urethane crosslinking agent, but the PET resin has limited compatibility with solvents and various additives. Therefore, since a uniform appearance is not obtained at the time of painting work, not only practical application is difficult, but also workability is insufficient for home use.

Therefore, the above polyester-based, epoxy-based, and urethane-modified polyester-based resins have been mainly used except for products requiring special paint properties. In particular, polyester resins having excellent mechanical properties and workability at the time of coating are most often used.

In general, PCM steel plate coatings using polyester resins are coated on corrosion resistant steel sheets such as hot dip galvanized steel sheets, galvanium steel sheets, aluminum steel sheets and cold zinc steel sheets, and the like for general building exterior materials, industrial exterior materials, household materials and other industrial materials. It has been used as. As architectural exterior materials, polyester paints lacked long-lasting durability in repeated external natural conditions such as ultraviolet light, acid rain, sulfur dioxide and wet and dry.

PCM steel plate paints for home use require high workability and high hardness. PCM steel sheets for general home appliances have been widely used coating compositions containing polyester resin as a main component, including melamine resin or isocyanate compound as a crosslinking agent, and small amounts of additives such as curing catalysts, antifoaming agents and leveling agents. However, in the paint composition, after coating the paint composition on a steel sheet, a polyester resin having a linear glass structure having a low glass transition temperature (Tg) was used in order to provide workability so that cracking does not occur during processing. . Since the linear polyester resin has a higher molecular weight and a smaller hydroxyl value than the PCM steel plate paint for building materials, the compatibility with the solvent is low. That is, when using the said linear polyester resin, although the workability of the coating film coated on the said steel plate is favorable, the hardness of the said coating film falls. Therefore, when the steel sheet is processed or transported, defects in which the steel sheets come into contact with each other or the surface of the coating film is damaged by manual operation of an operator are generated.

In addition, due to the low compatibility, the coating composition containing the linear polyester resin is converted into a suspension during storage, or in the winter season, such as winter, layer separation between the solvent and the resin occurs, precipitates and the like are formed. Therefore, when the linear polyester resin is applied as a paint, the pigment in the paint precipitates, the storage property is lowered, and the surface state of the paint is roughened with a decrease in gloss and stiffness after coating.

Accordingly, a first object of the present invention for solving the above problems is to provide an acrylic modified polyester resin that can be used as a coating composition for chemically and physically stable PCM steel sheet.

In addition, a second object of the present invention is to provide a method for producing an acrylic modified polyester resin that can be used as a chemically and physically stable coating composition for PCM steel sheet.

Acrylic modified polyester resin according to an embodiment of the present invention for achieving the first object is formed by condensation reaction of polyhydric alcohol and polyhydric acid, 50 to 90% by weight of a polyester resin intermediate containing a hydroxyl group; And 10 to 50% by weight of an acrylic urethane prepolymer formed by reacting an isocyanate compound with a metaacryl polyol having a structure as shown in Formula (I) below.

The metaacryl polyol having the formula (I) is alpha, an omega-methacrylic polyol, wherein R is a methyl group or a butyl group, n is 6 to 12 and a molecular weight is 1000.

In addition, the acrylic modified polyester resin manufacturing method according to an embodiment of the present invention for achieving the second object, first, by condensation reaction of polyhydric alcohol and polyhydric acid, the average molecular weight is 1500 to 15000, hydroxyl value is 20 to A polyester resin intermediate of 150 mgKOH / g was prepared. Subsequently, the acryl urethane prepolymer is prepared by reacting the metaacrylic polyol of the general formula (I) with an isocyanate compound. Subsequently, 10-50 wt% of the acrylic urethane prepolymer is reacted with a hydroxyl group contained in the 50-90 wt% polyester resin intermediate to produce an acrylic modified polyester resin.

As described above, by subjecting the polyester resin intermediate to the acrylic urethane prepolymer to which the metaacrylic polyol is applied, physical properties such as adhesion, solvent resistance, gloss, flexibility, and impact resistance of the polyester resin, and weather resistance, drying resistance, and resistance of the acrylic resin Acrylic modified polyester resins having physical properties such as chemical properties, hardness, and solvent compatibility can be mutually complemented. Therefore, the acrylic modified polyester resin is applied to the PCM steel sheet top coating composition for home appliances to be able to produce a PCM steel sheet top coating having excellent physical properties.

Hereinafter, the present invention will be described in detail.

Acrylic Modified Polyester Resin

The acrylic modified polyester resin of the present invention is a resin contained in a coating composition for PCM steel sheet coating, and an acrylic resin formed by reacting an isocyanate compound with a polyester resin intermediate containing a hydroxyl group and a metaacryl polyol having a structure such as the following formula (I) The urethane prepolymer is formed by binding reaction.

The said polyester resin intermediate is formed by condensation reaction of polyhydric alcohol and polyhydric acid, and contains a hydroxyl group. Examples of the polyhydric alcohol include ethylene glycol, propylene glycol, 1,4-butylene glycol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 2-methyl-1,3-propanediol, cyclo Hexanedimethylol, trimethylpentanediol, and the like. These can be used individually or in mixture.

Examples of the polyhydric acid include phthalic anhydride, tetrahydro phthalic anhydride, hexahydro phthalic anhydride, isophthalic acid, terephthalic acid, adipic acid, azelaic acid, sebacic acid, and cyclohexanediacid. Can be. These can be used individually or in mixture.

The polyester resin intermediate applied to prepare the acrylic modified polyester resin has an average molecular weight of 1500 to 15000 and a hydroxyl value of 20 to 150 mgKOH / g.

If the average molecular weight of the polyester resin intermediate is less than about 1500, there is a problem that the adhesion, impact resistance, flexibility and the like is lowered. On the other hand, if the average molecular weight exceeds about 15000, the viscosity of the paint is excessively increased and workability is lowered, which is not suitable for the continuous process. Therefore, it is preferable that the average molecular weight of the said polyester resin intermediate is about 1500-15000.

When the hydroxyl value of the polyester resin intermediate is less than about 20 mgKOH / g, the coupling reactor becomes smaller with respect to the methacrylic polyol, so that a limitation on the acrylic modification rate occurs and the coating film hardness is lowered. On the other hand, when the hydroxyl value exceeds about 150 mgKOH / g, the processability of the coating film is reduced. Therefore, it is preferable that the hydroxyl value of the said polyester resin intermediate is about 20-150 mgKOH / g.

The acrylic urethane prepolymer applied to prepare the acrylic modified polyester resin is formed by reacting a divalent isocyanate compound with a metaacryl polyol of the following general formula (I).

The methacrylic polyol having the formula (1) has a hydroxyl group at the terminal, and when R is a methyl group, it is methyl methacryl polyol, and when R is a butyl group, it is a butyl methacryl polyol. The methacrylic polyol has a molecular weight of about 1,000 and a molecular weight distribution of about 1.0 to 1.1.

The amount of the methacrylate used is 10 to 50% by weight of the total weight of the prepared polyester resin intermediate. Here, the use of the methacrylate is a reference to the polyester resin intermediate of the solid content. When the metaacrylic polyol is less than 10% by weight based on the solids content of the polyester resin, there is a problem that the effect of the present invention due to the introduction of an acrylic group into the polyester skeleton cannot be expected. On the other hand, when the amount of use exceeds 50% by weight, the portion of acryl occupies more than the portion occupied by polyester in the entire resin skeleton, so that the workability of the PCM steel plate undercoat can be reduced. Therefore, it is preferable to use the said metaacryl polyol in the ratio of 10-50 weight% with respect to the said polyester resin.

As an isocyanate compound which couple | bonds-reacts with the said metaacryl polyol in order to manufacture the said acrylic urethane prepolymer, an aromatic isocyanate compound, an alicyclic isocyanate compound, or an aliphatic isocyanate compound is mentioned, for example. However, since an aromatic isocyanate compound can reduce the weather resistance of the top coat of a PCM steel plate, it is preferable to use an alicyclic or aliphatic isocyanate compound in this invention.

As said isocyanate compound, hexamethylene diisocyanate, isophorone diisocyanate, 4, 4- dicyclohexyl methane diisocyanate, etc. are mentioned, for example. These can be used individually or in mixture.

When the isocyanate compound is a one-shot reaction with the polyester resin and the metaacryl polyol in the urethane bond reaction step of the polyester resin and the metaacryl polyol, the metaacryl polyol is irregularly present in the skeleton of the final resin. Since quality control and coating property control may be inconsistent, they are applied to make acrylic urethane prepolymers. Therefore, it is preferable that an acrylic urethane prepolymer and the said polyester resin bond-react.

At this time, if the reaction equivalent ratio of the isocyanate compound to the methacrylic polyol is less than 2, the viscosity of the acrylic urethane prepolymer becomes high, which leads to an increase in the viscosity of the final acrylic modified polyester resin, which adversely affects paint manufacturing workability and painting workability. Can be. On the other hand, when the reaction equivalence ratio is greater than 2.2, the content of acryl compound remaining unreacted may increase, thereby limiting the ratio of acryl. Therefore, the equivalent ratio of the isocyanate compound to the methacrylic polyol is preferably 1: 2 to 2.2.

Acrylic modified polyester resin of the present invention is 50 to 90% by weight of the polyester resin intermediate containing a hydroxyl group and 10 to 50% by weight of the acrylic urethane prepolymer formed by the reaction of the isocyanate compound with a metaacryl polyol having a structure as shown in the formula (I) % Is formed by reacting.

When the acrylic modified polyester resin of the present invention forms a polyester resin intermediate and an acrylic urethane prepolymer, K-100 (SK), K-150 (SK), and cyclo Hexone and isophorone may be applied to adjust the viscosity of the acrylic modified polyester resin, or an aromatic solvent may be further added after the acrylic modified polyester resin is formed.

Polyhydric alcohols used in the present invention include ethylene glycol, propylene glycol, 1,4-butylene glycol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 2-methyl-1,3-propane At least one selected from the group consisting of diol, cyclohexanedimethylol, trimethylpentanediol, and the like may be used.

In addition, the polyhydric acids used in the present invention include phthalic anhydride, tetrahydro phthalic anhydride, hexahydro phthalic anhydride, isophthalic acid, terephthalic acid, adipic acid, azelaic acid, sebacic acid and cyclohexanedi. At least one selected from the group consisting of an acid may be used.

Acrylic modified polyester resin manufacturing method

First, polyhydric alcohol and polyhydric acid are condensation-reacted, and the polyester resin intermediate containing a hydroxyl group is formed.

In detail, the polyhydric acid and the polyhydric alcohol are added to the reactor in which the catalyst is present, and then heated to about 90 to 120 ° C. Thereafter, while the heated reactant is melted and stirred to cause a condensation reaction, the condensation water (H ₂ O) generated by the condensation reaction is slowly heated to about 230 ° C., and then the temperature of the reactant reaches about 230 ° C. The holding reaction and the reflux reaction are carried out at the temperature. After the acid value of the reaction is less than 10mgKOH / g to cool to form a polyester resin intermediate. At this time, the temperature increase rate should be adjusted so that the alcohol component does not azeotropic in the reaction condensed water. The polyester resin intermediate produced by such a method has the characteristic that an average molecular weight is 1500-15000, and a hydroxyl value is 20-150 mgKOH / g.

The polyhydric alcohols and polyvalent acids and descriptions applied to form the polyester resin intermediates are described above in detail and are omitted to avoid duplication.

Subsequently, an isocyanate compound is reacted with methacrylate corresponding to 10 to 50% by weight of the total weight of the polyester resin intermediate to produce an acrylic urethane prepolymer.

 Specifically, the isocyanate compound having an equivalent ratio of 2 to 2.2 was added to 1 equivalent of the methacrylic polyol, and then gradually heated to 70 ° C. while stirring. The isocyanate equivalent is then measured while maintaining at this temperature to approach the theoretical equivalent to cool the reactant to produce an acrylic urethane prepolymer.

Subsequently, 10-50% by weight of the acrylic urethane prepolymer is reacted with a hydroxyl group of the polyester resin intermediate having 50 to 90% by weight to prepare an acrylic modified polyester resin.

Specifically, the acrylic urethane prepolymer is introduced into a polyester resin intermediate, and gradually heated to 80 ° C. while stirring under nitrogen. Subsequently, the reaction mixture is cooled until the isocyanate peak disappears using the IR spectrum (infrared spectrometer) at this temperature. Thereafter, a diluent solvent was further added to prepare an acrylic modified polyester resin having a solid content of 55 to 65%.

The acrylic modified polyester resin prepared by the method improves the storage properties of the resin and the paint by increasing the compatibility with the solvent while maintaining the excellent mechanical and chemical properties of the PCM steel plate paint.

Hereinafter, the present invention will be described with reference to preferred embodiments and comparative examples. However, the above embodiments do not limit the present invention.

Polyester resin intermediate synthesis.

Synthesis Example 1-4

The reaction mixture was heated to about 100 ° C. while adding a small amount of nitrogen after adding a polyacid raw material and a total amount of polyhydric alcohol among the composition components shown in Table 1 to the four-necked flask. Subsequently, when the heated reactant was melted, stirring was started with a stirrer and heated slowly to 230 ° C. while removing condensed water (H ₂ 0). At this time, the temperature increase rate was adjusted so that the components of alcohol in the condensed water do not come azeotropic. Subsequently, when the temperature of the reaction mass reached 230 ° C., a holding reaction and a reflux reaction were performed at this temperature. After the acid value of the reaction product is less than 10mgKOH / g after cooling and adding a diluted solvent K-150 (SK Co., Ltd.), the solid content is 64 to 66%, polyester resin polymer corresponding to Synthesis Examples 1-4 Were prepared respectively.

Raw material name Synthesis Example 1 Synthesis Example 2 Synthesis Example 3 Synthesis Example 4 Polyester resin intermediates Mountain Isophthalic Acid Phthalic Acid Adipic Acid 960 (g) 210 (g) 390 (g) 960 210 390 960 (g) 210 (g) 390 (g) 960 (g) 210 (g) 390 (g) Polyhydric alcohol Neopentylglycol 1,6-hexanediol trimethylpropanol 1150 (g)-25 (g) 1150 (g)-25 (g) 850 (g) 350 (g) 25 (g) 850 (g) 350 (g) 25 (g)

Acrylic Urethane Prepolymer Synthesis

Synthesis Examples 5-8

The metaacryl polyol and the isocyanate compound among the composition components shown in the following Table 2 were added to the four neck flask, and the temperature was gradually raised to 70 ° C. while being careful of rapid exotherm while stirring under nitrogen. Subsequently, when the isocyanate equivalent weight was measured while maintaining the temperature, and the theoretical equivalent was approached, the reactant was cooled, followed by the addition of a dilute solvent K-150 (SK Co., Ltd.), where the solid content was 64 to 66%. Acrylic urethane prepolymers corresponding to 8 were prepared, respectively.

Acrylic Urethane Prepolymer Raw material name Synthesis Example 5  Synthesis Example 6 Synthesis Example 7 Synthesis Example 8 Methacrylic polyol Butyl Methacrylic Polyol - 360 (g) - 360 (g) Methyl methacryl polyol 240 (g) - 240 (g) - Isocyanate Compound 4,4-dicyclohexylmethane diisocyanate - 198 (g) - 198 (g) Isophorone diisocyanate 112 (g) - 112 (g) -

Acrylic Modified Polyester Resin

Example 1

The polyester resin polymer of Synthesis Example 1 and the acrylic urethane prepolymer of Synthesis Example 5 were added to a four-necked flask, and then the reaction mass was gradually heated to 80 ° C. while stirring in an atmosphere where nitrogen was added. When the isocyanate peak disappeared using the IR spectrum (infrared spectrometer) while maintaining the temperature, the reaction product was cooled, and then diluted with PMA (DOW), a diluent solvent, to prepare an acrylic modified polyester resin having a solid content of 60%.

Example 2

The polyester resin polymer of Synthesis Example 2 and the acrylic urethane prepolymer of Synthesis Example 6 were added to a four-necked flask, and then the reaction mass was gradually heated to 80 ° C. while stirring in an atmosphere where nitrogen was added. When the isocyanate peak disappeared using the IR spectrum (infrared spectrometer) while maintaining the temperature, the reaction product was cooled, and then diluted with PMA (DOW), a diluent solvent, to prepare an acrylic modified polyester resin having a solid content of 60%.

Example 3

Into a four-necked flask, the polyester resin polymer of Synthesis Example 3 and the acrylic urethane prepolymer of Synthesis Example 7 were charged, and the reaction mass was gradually heated to 80 ° C while stirring in an atmosphere where nitrogen was added. When the isocyanate peak disappeared using the IR spectrum (infrared spectrometer) while maintaining the temperature, the reaction product was cooled, and then diluted with PMA (DOW), a diluent solvent, to prepare an acrylic modified polyester resin having a solid content of 60%.

Example 4

Into a four-necked flask, the polyester resin polymer of Synthesis Example 4 and the acrylic urethane prepolymer of Synthesis Example 8 were charged, and then the reaction mass was gradually heated to 80 ° C while stirring in an atmosphere where nitrogen was added. The reaction was cooled when the reactants were free of isocyanate peaks using IR spectra (infrared spectroscopy) while maintaining at this temperature. Thereafter, a diluent solvent PMA (DOW) was added to the resultant to prepare an acrylic modified polyester resin having a solid content of 60%.

Comparative Example 1

A four-necked flask with a capacity of 5 L was equipped with a thermometer, condenser, stirrer, water removal condenser, heating device and variable speed stirrer. About 830 parts by weight of neopentyl glycol, about 450 parts by weight of 1,6-hexanediol, about 1650 parts by weight of isophthalic acid and about 210 parts by weight of adipic acid were added to the flask and refluxed at about 235 ° C. using xylene as a solvent. Condensation reaction. A polyester resin having a Gardner bubble viscosity of Z to Z3, about 60% by weight based on the total mixture, and an acid value of about 5 mgKOH / g was prepared. The hydroxyl value of the said synthetic resin is about 20 mgKOH / g.

PCM Steel Plate Paint Manufacturing

Experimental Example 1

The particle size was adjusted to 7 by mixing about 500 parts by weight of the thermosetting modified polyester resin obtained in Example 1 and about 200 parts by weight of titanium dioxide by spraying with a mini motor mill. About 30 parts by weight of hexamethylenemethoxymelamine, about 150 parts by weight of K-150 (SK Co., Ltd.) as an aromatic solvent, about 100 parts by weight of 2-ethoxyethyl acetate and about 1 part by weight of p-toluenesulfonic acid catalyst It added and manufactured the coating material for PCM steel plate.

Experimental Example 2

The particle size was adjusted to 7 by mixing about 500 parts by weight of the thermosetting modified polyester resin obtained in Example 2 and about 200 parts by weight of titanium dioxide, and dispersing it in a mini motor mill. About 30 parts by weight of hexamethylene methoxymelamine, about 150 parts by weight of aromatic solvent K-150 (SK Co., Ltd.), about 100 parts by weight of 2-ethoxyethyl acetate and about 1 part by weight of p-toluenesulfonic acid catalyst It added and manufactured the coating material for PCM steel plate.

Experimental Example 3

The particle size was adjusted to 7 by mixing about 500 parts by weight of the thermosetting modified polyester resin obtained in Example 3 and about 200 parts by weight of titanium dioxide by dispersing it in a mini motor mill. About 30 parts by weight of hexamethylenemethoxymelamine, about 150 parts by weight of K-150 (SK Co., Ltd.), about 100 parts by weight of 2-ethoxyethyl acetate and about 1 part by weight of p-toluenesulfonic acid catalyst are added. To prepare a paint for PCM steel sheet.

Experimental Example 4

The particle size was adjusted to 7 by mixing about 500 parts by weight of the thermosetting modified polyester resin obtained in Example 4 and about 200 parts by weight of titanium dioxide, and dispersing it in a mini motor mill. About 30 parts by weight of hexamethylenemethoxymelamine, about 150 parts by weight of K-150 (SK Co., Ltd.), about 100 parts by weight of 2-ethoxyethyl acetate and about 1 part by weight of p-toluenesulfonic acid catalyst are added. To prepare a paint for PCM steel sheet.

Comparative Experimental Example 1

The particle size was adjusted to 7 by mixing about 500 parts by weight of the polyester resin obtained in Comparative Example 1 and about 200 parts by weight of titanium dioxide by dispersing with a mini motor mill. About 30 parts by weight of hexamethylenemethoxymelamine, about 150 parts by weight of K-150 (SK Co., Ltd.), about 100 parts by weight of 2-ethoxyethyl acetate and about 1 part by weight of p-toluenesulfonic acid catalyst are added. To prepare a paint.

Evaluation test of paint

Using a zinc phosphate-treated PCM steel sheet as a base material to coat the base material, and the paints prepared in each of Experimental Examples 1 to 4 and Comparative Experimental Example 1 were coated on top. The thickness of the top coat was about 15 ± 2 microns and the surface temperature of the substrate was about 232 ° C. ± 5. Thereafter, the gloss, MEK Rubbing, processability, pencil hardness, CET, acid resistance and alkali resistance of the coating film prepared by the coating materials of Experimental Examples 1 to 4 and Comparative Experimental Example 1 were measured, respectively, and the results are shown in Table 3. It was.

Paint Composition Experimental Example 1 Experimental Example 2 Experimental Example 3 Experimental Example 4 Comparative Experimental Example 1 Glossy (60 °) 87 88 89 89 88 MEK Rubbing 100 or more 100 or more 100 or more 100 or more 100 or more Machinability 1T 1T 0T 1T 0T Pencil hardness F-H H ~ 2H F H B C.E.T 100/100 100/100 100/100 100/100 100/100 Acid resistance ◎ ◎ ◎ ◎ ○ Alkali resistance ◎ ◎ ◎ ◎ ○ Resin stability ◎ ◎ ◎ ◎ △ Solvent dilution ◎ ◎ ◎ ◎ △

Evaluation: ◎ is very good, ○ is good, △ is normal and X means bad.

1. gloss; It was measured by ASTM-D-523 (a standard for measuring the gloss reflected by non-metallic materials determined by the American Society for Testing and Materials).

2. MEK Rubbing property; Measurement was made by NCCA-II-18 (evaluation specification for solvent resistance as determined by the National Coil Coaters Association).

3. Machinability; Measurement was made by NCCA-II-19 ("T" band test method as defined by the National Coil Coaters Association).

4. pencil hardness; Measurement was made by NCCA-II-12 (relative pencil hardness evaluation specification set by the National Coil Coaters Association).

5. C.E.T; The measurement was carried out by NCCA-II-20 (Possessing adhesion test method as defined by the National Coil Coaters Association).

6. Acid and alkali resistance; It was measured by ASTM-D-1308 (International Standard for Household Chemicals Used on Finishes of Organic Substances as defined by the American Society for Testing and Materials).

Referring to Table 3, the pencil hardness and chemical resistance of the coating film formed using the coating composition prepared by the method of Examples 1 to 4 of the present invention exhibited superior performance to the paint prepared by the method of the conventional Comparative Example 1. It was. The workability and pencil hardness items are in contrast to the physical properties. In Comparative Example 1, the workability was excellent in workability, but the pencil hardness was greatly decreased. On the other hand, in the case of Examples 1 to 4 of the present invention it can be seen that the workability and hardness showed excellent performance at the same time. The appearance of the coating film was better than the coating film according to Comparative Experiment Example 1 of the present invention modified acrylic, and the Examples showed better than Comparative Experiment Example 1 in terms of resin stability and solvent dilution.

As described above, according to the present invention, an acrylic modified polyester resin can be produced by combining and reacting an acrylic urethane prepolymer formed of a methacrylic polyol and an isocyanate compound to a polyester resin intermediate containing a hydroxyl group.

The acrylic modified polyester resin is applied to the paint to improve the storage properties of the paint for PCM steel plate which can increase the compatibility with the solvent while maintaining excellent mechanical and chemical properties. By producing a physicochemically excellent paint in this manner, it is possible to stably form a coating film while maintaining excellent characteristics on the PCM steel sheet for home appliances.

As described above, although described with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified without departing from the spirit and scope of the invention described in the claims below. And can be changed.

Claims (13)

50 to 90% by weight of a polyester resin intermediate formed by condensation reaction between a polyhydric alcohol and a polyvalent acid and including a hydroxyl group; And An acrylic modified polyester resin formed by reacting 10 to 50% by weight of an acrylic urethane prepolymer formed by reacting a metaacryl polyol having an structure represented by the following formula (I) with an isocyanate compound.

(In the formula (I), R is a methyl group or a butyl group, n is 6 to 12) The acrylic modified polyester resin of claim 1, wherein the polyester resin intermediate has an average molecular weight of 1500 to 15000. The acrylic modified polyester resin according to claim 1, wherein the polyester resin intermediate has a hydroxyl value of 20 to 150 mgKOH / g. The acrylic modified polyester resin according to claim 1, wherein 10 to 50% by weight of the metaacryl polyol is used based on the total weight of the polyester resin intermediate. The method of claim 1, wherein the polyhydric alcohol is ethylene glycol, propylene glycol, 1,4-butylene glycol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 2-methyl-1,3- Acrylic modified polyester resin, characterized in that at least one selected from the group consisting of propanediol, cyclohexanedimethylol and trimethylpentanediol. The polyvalent acid according to claim 1, for example, phthalic anhydride, tetrahydro phthalic anhydride, hexahydro phthalic anhydride, isophthalic acid, terephthalic acid, adipic acid, azelaic acid, sebacic acid and cyclohexanedi Acrylic modified polyester resin, characterized in that at least one selected from the group consisting of acid. The acrylic modified polyester resin of claim 1, wherein the acrylic urethane prepolymer is reacted with 2 to 2.2 equivalents of an isocyanate compound with respect to 1 equivalent of the metaacryl polyol. The acryl compound of claim 1, wherein the isocyanate compound is at least one selected from the group consisting of hexamethylene diisocyanate, isophorone diisocyanate and 4,4-dicyclohexylmethane diisocyanate as a divalent isocyanate compound. Modified polyester resin. Iii) condensing the polyhydric alcohol and polyhydric acid to prepare a polyester resin intermediate having an average molecular weight of 1500 to 15000 and a hydroxyl value of 20 to 150 mgKOH / g; Ii) preparing an acrylic urethane prepolymer by reacting a metaacrylic polyol of formula (I) with an isocyanate compound; And I) a method of producing an acrylic modified polyester resin comprising the step of reacting 10 to 50% by weight of an acrylic urethane prepolymer with a hydroxyl group contained in an intermediate of 50 to 90% by weight of a polyester resin.

(In the formula (I), R is a methyl group or a butyl group, n is 6-12) 10. The method of claim 9, wherein the acrylic urethane prepolymer is formed by reacting 2 to 2.2 equivalents of an isocyanate compound with respect to 1 equivalent of the metaacrylic polyol. 10. The method of claim 9, wherein 10 to 50% by weight of the methacrylic polyol is used based on the total weight of the polyester resin intermediate. The method of claim 9, wherein the isocyanate compound is a divalent isocyanate compound, characterized in that it comprises at least one selected from the group consisting of hexamethylene diisocyanate, isophorone diisocyanate and 4,4-dicyclohexylmethane diisocyanate. Acrylic modified polyester resin production method. The method of manufacturing an acrylic modified polyester resin according to claim 9, further comprising adding the solvent.