KR20170136069A - Polyester resin comprisng biomass-derived monomer and method for preparing the same, and powder coating composition comprising the resin - Google Patents

Abstract

The present invention relates to a polyester resin comprising a biomass-derived monomer, a production method of the resin, and a powder coating composition comprising the resin. More specifically, the present invention relates to the polyester resin, the production method of the resin, and the powder coating composition comprising the resin, wherein the resin is capable of solving a depletion problem of petroleum resources that are finite resources, is environmentally friendly, and is capable of remarkably improving weatherability and flexibility of a coating film when the polyester resin is used in powder coating by comprising a biomass-derived anhydrosugar alcohol derivative with improved reactivity as a repeating unit.

Description

TECHNICAL FIELD [0001] The present invention relates to a polyester resin containing a biomass-derived monomer, a method for producing the same, and a powder coating composition comprising the resin. [0002]

The present invention relates to a polyester resin containing a biomass-derived monomer, a process for producing the polyester resin, and a powder coating composition containing the resin, and more particularly to a polyester resin containing a biomass-derived monomer, A polyester resin capable of solving the problem of depletion of a petroleum resource which is a finite resource and being environmentally friendly and capable of remarkably improving the weatherability and flexibility of a coating film when used in powder coatings, a method for producing the same, and a powder coating ≪ / RTI >

Hydrogenated sugar (also referred to as " sugar alcohol ") refers to a compound obtained by adding hydrogen to the reducing end group of a saccharide, generally HOCH ₂ (CHOH) _n CH ₂ OH (wherein n is an integer of 2 to 5 ), And classified into tetritol, pentitol, hexitol and heptitol (C 4, 5, 6 and 7, respectively), depending on the number of carbon atoms. Among them, hexitol having six carbon atoms includes sorbitol, mannitol, iditol, galactitol and the like, and sorbitol and mannitol are particularly useful substances.

Anhydrosugar alcohol has a diol form with two hydroxyl groups in the molecule and can be prepared by utilizing hexitol derived from starch (for example, Korean Patent No. 10-1079518, Korean Patent Laid- -2012-0066904). Since alcohol-free alcohol is an eco-friendly substance derived from renewable natural resources, there has been much interest for a long time and studies on the manufacturing method have been carried out. Among these alcohol-free alcohols, isosorbide prepared from sorbitol has the widest industrial application currently.

The use of anhydrous alcohol is widely used in the treatment of cardiovascular diseases, patches, adhesives, oral cleansers and the like, solvents for compositions in the cosmetics industry, and emulsifiers in the food industry. In addition, it is possible to increase the glass transition temperature of a polymer substance such as polyester, PET, polycarbonate, polyurethane, and epoxy resin, to improve the strength of these materials, and to be an environmentally friendly material derived from natural materials. useful. It is also known to be used as an environmentally friendly solvent for adhesives, environmentally friendly plasticizers, biodegradable polymers, and water-soluble lacquers.

As such, alcohol-free alcohol has attracted a great deal of attention due to its versatility and its use in real industry is increasing.

Korean Patent Laid-Open No. 10-2012-0113883 discloses a polyester resin for a liquid paint having an alcohol functional group, which is obtained by copolymerizing a diacid component, a diol component including isosorbide, and lactic acid or a derivative thereof together in a single step . However, since lactic acid has both alcohol and acid functional groups, the competitive reaction proceeds selectively. Therefore, in the polyester resin manufacturing method disclosed in the above document, the reactivity is lowered during the production of resin and the reaction time is long, There is a problem in that the color of the produced resin is deteriorated with an increase in length, and the dispersing workability and heat resistance are deteriorated.

The present invention can solve the problem of depletion of petroleum resources, which is a finite resource, by including an anhydrosugar alcohol derivative having improved reactivity derived from biomass as a repeating unit, and is eco-friendly and remarkably improves the weatherability and flexibility of a coating film when used in powder coatings And a method for producing the same, and a powder coating composition comprising the resin.

In order to solve the above-mentioned technical problems, the present invention relates to a process for producing a polyol having a repeating unit derived from a diol component containing an anhydride alcohol-alkylene glycol, which is an adduct obtained by reacting a terminal hydroxyl group of an alcohol with no anhydride with an alkylene oxide; And a repeating unit derived from a polyfunctional acid component.

According to another aspect of the present invention, there is provided a process for preparing a monohydric alcohol-alkylene glycol, comprising the steps of: (1) reacting an anhydrosugar alcohol with an alkylene oxide to prepare an adduct, (2) preparing a prepolymer by reacting the diol component containing anhydrosugar alcohol-alkylene glycol prepared in the step (1) with a polyvalent acid component; And (3) reacting the prepolymer prepared in step (2) with a polyfunctional acid component to prepare a polyester resin.

According to another aspect of the present invention, there is provided a powder coating composition comprising a polyester resin and a curing agent of the present invention.

The polyester resin according to the present invention can solve the problem of depletion of petroleum resources, which is a finite resource, by including an anhydrosugar alcohol derivative having improved reactivity derived from biomass as a repeating unit, and is eco-friendly. When used in powder coatings, Can be significantly improved.

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

The polyester resin of the present invention comprises a repeating unit derived from a diol component including an anhydride alcohol-alkylene glycol, which is an adduct obtained by reacting a terminal hydroxyl group of an alcohol with no anhydride with an alkylene oxide; And a repeating unit derived from a polyfunctional acid component.

The above-mentioned dihydric alcohol generally means any substance obtained by removing one or more water molecules from a compound obtained by adding hydrogen to a reducing end group of a saccharide, which is generally called hydrogenated sugar or sugar alcohol. do.

In the present invention, dianhydrohexitol, which is a dehydrate of hexitol, can be preferably used as the alcohol without sugar, more preferably, the alcohol without sugar is isosorbide (1,6-dianhydroisorbitol), iso May be selected from the group consisting of mannide (1,6-dianhydro mannitol), isodide (1,6-dianhydroiditol) and mixtures thereof, and most preferably isosorbide can be used.

In the present invention, the term " anhydride alcohol-alkylene glycol " means an alcohol having a terminal (e.g., both terminal) hydroxyl group and an alkylene oxide (e.g., C ₁ -C ₄ alkylene oxide, (For example, both terminals) of the anhydride alcohol is substituted with a hydroxyalkyl group, which is a ring-opened form of an alkylene oxide, as an adduct obtained by reacting an alcohol . For example, the result of addition of ethylene oxide to both terminal hydroxyl groups of isosorbide is as follows.

In the present invention, the diol component used in the production of the polyester resin may further comprise a diol compound other than the above-mentioned anhydropoly alcohol-alkylene glycol such as an aliphatic diol, an alicyclic diol, an aromatic diol or a combination thereof And preferably, an aliphatic diol.

As the aliphatic diol, for example, a linear or branched aliphatic diol having 2 to 8 carbon atoms can be used. Specific examples thereof include ethylene glycol, diethylene glycol, triethylene glycol, 1,3-propanediol (propylene glycol) 1,2-propanediol, 1,4-butanediol (1,4-butylene glycol), 1,3-butanediol, 1,2-butanediol, 2,2- ), Pentanediol (e.g., 1,5-pentanediol, 1,4-pentanediol, 1,3-pentanediol, 1,2-pentanediol and the like), hexanediol 1,6-hexanediol, 1,6-hexanediol, 1,5-hexanediol, 1,4-hexanediol, Heptanediol, 1,5-heptanediol, 1,4-heptanediol, 1,3-heptanediol, 1,2-heptanediol, etc.), and combinations thereof.

As the alicyclic diol, for example, an alicyclic diol having 5 to 20 carbon atoms and containing 1 to 4 5-atomic ring structures or 6-atomic ring structures can be used. Specific examples thereof include 1,4-cyclohexane Diol, 1,3-cyclohexanediol, 1,2-cyclohexanediol, 1,4-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,2-cyclohexanedimethanol, tetramethylcyclobutanediol, Tricyclodecane dimethanol, adamantanediol, isosorbide, and combinations thereof.

As the aromatic diol, for example, an aromatic diol having 6 to 20 carbon atoms and containing 1 to 4 aromatic ring structures can be used. Specific examples thereof include bisphenol A, 4,4'-dihydroxy-diphenyl Sulfone, 4,4'-biphenol, hydroquinone, 4,4'-dihydroxy-diphenyl ether, 3- (4-hydroxyphenoxy) phenol, bis May be used.

In the present invention, the diol component used in the production of the polyester resin includes, based on 100 mol% of the total diol component, 1 to 90 mol% of an alcohol-free alcohol-alkylene glycol and an alcohol May contain from 10 to 99 mol% of diol compounds (for example, aliphatic diols, alicyclic diols and / or aromatic diols), or from 5 to 80 mol% of anhydrosugar alcohol-alkylene glycol and anhydrosugar alcohol-alkylene glycol 20 to 95 mol% of a diol compound, or 10 to 70 mol% of an alcohol-free alcohol-alkylene glycol and 30 to 90 mol% of a diol compound other than an alcohol-free alcohol-alkylene glycol. If the content of the anhydride alcohol-alkylene glycol in the total diol component is lower than the above-mentioned level, the reactivity in the production of the resin is lowered and the reaction time becomes longer, and the properties such as color and heat resistance may be deteriorated. On the contrary, The glass transition temperature of the produced resin is lowered, the storage stability of the product is lowered, and the production of the product is not easy, so that application to powder coatings may become difficult.

In the present invention, as the polybasic acid component used in the production of the polyester resin, a dicarboxylic acid, a triacic acid, or a mixture thereof may be used. Specific examples of the dicarboxylic acid include an aromatic dicarboxylic acid having a carbon number of 8 to 14 (E.g., terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid, diphenyldicarboxylic acid, etc.), aliphatic dicarboxylic acids having 4 to 12 carbon atoms (such as (1,4- or 1,3-) cyclohexane Dicarboxylic acid, phthalic acid, sebacic acid, succinic acid, maleic acid, fumaric acid, adipic acid, glutaric acid, and the like), and combinations thereof. As the triacetic acid, trimellitic acid or its anhydride may be used. Can be used.

In the present invention, there is no particular limitation on the ratio of the amount of the diol component to the amount of the polyvalent acid component used in the production of the polyester resin. For example, the amount of the polyvalent acid component may be 80 mole to 120 mole based on 100 mole of the entire diol component , Or 90 mole to 110 mole. If the amount of the polyvalent acid component is lower than the above-mentioned level, the content of the curing agent may be lowered in the preparation of the powder coating, which may cause a problem that the chemical resistance, impact resistance and hardness are lowered. On the other hand, If it is higher than the above-mentioned level, there may be a problem that appearance and leveling of the coating film are lowered when applied to powder coatings.

According to one embodiment of the present invention, the polyester resin comprises (1) a step of reacting an anhydrosugar alcohol with an alkylene oxide to produce an alcohol-free alcohol-alkylene glycol as an adduct; (2) preparing a prepolymer by reacting the diol component containing anhydrosugar alcohol-alkylene glycol prepared in the step (1) with a polyvalent acid component; And (3) reacting the prepolymer prepared in step (2) with a polyfunctional acid component to prepare a polyester resin. Here, the anhydride alcohol-alkylene glycol, the diol component and the polyvalent acid component are as described above.

In the above step (1), the reaction of the anhydropoly alcohol with the alkylene oxide can be carried out in the presence of a catalyst, for example, an acid catalyst (for example, sulfuric acid, At a raised temperature (e.g., 110 to 180 占 폚, or 120 to 160 占 폚) in the presence of a basic catalyst (for example, a strong base catalyst such as sodium hydroxide) To 8 hours or from 2 hours to 4 hours, but is not limited thereto. The reaction molar ratio of the anhydric alcohol and the alkylene oxide may be, for example, 2 to 20 moles, preferably 5 to 10 moles, of the alkylene oxide per 1 mole of the alcohol without anhydride, but is not limited thereto.

In the step (2), the reaction of the diol component containing an alcohol-free alcohol-alkylene glycol with a polyacid component (preferably a diacid component) is carried out by using a catalyst such as an organotin catalyst (E.g., 200 占 폚 to 280 占 폚, or 240 占 폚 to 250 占 폚) in the presence of an organic titanium catalyst (e.g., tin oxide or the like), an organic titanium catalyst (such as tetra-n-butyl titanate) ), But is not limited thereto. The prepolymer obtained as a result of the step (2) may have a hydroxyl value of 30 to 40 mg KOH / g, an acid value of 1 to 10 mg KOH / g, a viscosity of 4,000 to 6,000 cPs Viscosity), and the number average molecular weight may be 1,500 to 2,500, but is not limited thereto.

In the above step (3), the reaction of the prepolymer and the polyvalent acid component (preferably a trivalent acid, or a mixture of trivalent and divalent acids) is optionally carried out in the presence of a catalyst (such as a tin catalyst, for example monobutyltin oxide) (E.g., 165 ° C to 215 ° C, or 175 ° C to 205 ° C), in the presence of a solvent, such as, but not limited to, The polyester resin obtained as a result of the step (3) may have an acid value of 40 to 60 mgKOH / g and a viscosity of 200 to 6,000 cPs, preferably 2,000 to 4,000 cPs, Preferably from 3,000 to 4,000 cPs, a glass transition temperature of 55 to 100 ° C, preferably 55 to 70 ° C, more preferably 55 to 65 ° C, a number average molecular weight of 3,000 to 5,000, May be 3,500 to 4,500, but is not limited thereto.

Further, when a polyester resin is cured with an epoxy curing agent, an additive for increasing the reaction rate, such as ethyltriphenylphosphonium bromide, can be further used in the step (3).

The polyester resin of the present invention as described above can remarkably improve the weatherability and flexibility of the coating film when used in powder coatings.

Therefore, according to another aspect of the present invention, there is provided a powder coating composition comprising the polyester resin of the present invention and a curing agent.

As the curing agent, a curing agent usually used in the powder coating composition may be used without limitation, for example, an epoxy resin curing agent may be used, and as the epoxy resin curing agent, a phenol compound (for example, bisphenol A, bisphenol F, ) And an epoxy resin may be used, but the present invention is not limited thereto.

There is no particular limitation on the amount of the polyester resin and the curing agent contained in the powder coating composition of the present invention. For example, based on 100 parts by weight of the total of the polyester resin and the curing agent, 40 to 80 parts by weight of the polyester resin, 60 to 70 parts by weight of a polyester resin, and 30 to 50 parts by weight of a curing agent. However, the present invention is not limited thereto.

The powder coating composition of the present invention may further comprise at least one additive usually used in powder coating compositions. Such additives include, for example, 1 (one) selected from a pinhole inhibitor (e.g., benzoin), a flow improver, a wax component (e.g., polyethylene wax), a white pigment (e.g., titanium dioxide), and an extender pigment More than one species may be used, but is not limited thereto. The amount of the additive to be used is not particularly limited. For example, the pigment component may be used in an amount of 1 to 70 parts by weight based on 100 parts by weight of the total amount of the polyester resin and the curing agent, and the other additive component may be used in an amount of 0.1 to 10 parts by weight , But is not limited thereto.

Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples. However, the scope of the present invention is not limited thereto.

Example

Production of polyester resin

[Example 1-1]

Step 1: Preparation of isosorbide-ethylene glycol

73.1 g of isosorbide, 110 g of ethylene oxide and 0.2 g of sodium hydroxide as a catalyst were charged into a reactor equipped with a nitrogen gas pipe and a column equipped with a cooling device, a stirrer, a thermometer and a heater, and allowed to gradually warm. And then reacted while maintaining the temperature at 120 to 160 캜 for 2 hours to 4 hours to prepare isosorbide-ethylene glycol having a form in which the hydrogen of the hydroxyl group at both ends of the isosorbide was substituted with a hydroxyethyl group.

Step 2: Preparation of prepolymer

Ethylene glycol, 22.55 g of 1,4-butylene glycol, 10 g of isosorbide-ethylene glycol produced in the first step, 40.0 g of terephthalic acid, 43.55 g of cyclohexanedicarboxylic acid, 36.55 g of adipic acid, 468.9 g of neopentyl glycol, And 3.2 g of monobutyltin oxide (Bitti-300) as a catalyst were placed in a five-necked flask containing a nitrogen gas pipe and a column equipped with a cooling device, a stirrer, a thermometer and a heater, and the temperature was gradually raised. When the temperature of 120 ° C to 160 ° C is reached, the condensed water is flowed out. From this time, while maintaining the glycol in the condensed water, the temperature is raised to about 240 ° C to 250 ° C. Then, 1.3g of tributylphosphite is added, 33 mg KOH / g, an acid value of 4 mg KOH / g, a viscosity of 5,000 cPs (Brookfield viscosity at 175 ° C) and a number average molecular weight of 2,000.

Step 3: Production of polyester resin

1,200 g of the prepolymer prepared in the second step, 130.6 g of trimellitic anhydride and 20.7 g of adipic acid were placed in a five-necked flask containing a nitrogen gas pipe and a cooling device equipped with a stirrer, a thermometer and a heater, , The reaction temperature was maintained at 175 ° C to 205 ° C, and the reaction was carried out while removing the condensed water. Finally, in order to increase the degree of polymerization of the polyester resin, condensed water and unreacted materials that have not been extracted in polyester resin are removed using nitrogen excess or reduced pressure (50 to 200 mmHg), and 4.9 g of ethyltriphenylphosphonium bromide is charged To prepare a polyester resin having desired properties. The resulting final polyester resin had an acid value of 53 mgKOH / g, a viscosity of 3,400 cPs (Brookfield viscosity at 200 ° C), a glass transition temperature of 59 ° C and a number average molecular weight of 3,500.

[Example 2-1]

The amount of adipic acid used was changed from 35.55 g to 24.3 g, the amount of ethylene glycol used was changed from 24.8 g to 16.8 g, the amount of 1,4-butylene glycol was changed from 22.5 g to 18.9 g, the amount of isophorone- Except that the amount of glycol used was changed from 210 g to 260 g and the amount of trimellitic anhydride used was changed from 130.6 g to 145.8 g and the amount of adipic acid used was changed from 20.7 g to 0 g in the polyester resin production step, A polyester resin was prepared in the same manner as in Example 1-1. The resulting final polyester resin had an acid value of 51 mgKOH / g, a viscosity of 3,100 cPs (Brookfield viscosity at 200 ° C), a glass transition temperature of 60 ° C and a number average molecular weight of 3,800.

[Example 3-1]

Step 1: Preparation of isosorbide-propylene glycol

73.1 g of isosorbide, 145 g of propylene oxide and 0.2 g of sodium hydroxide as a catalyst were charged into a reactor equipped with a nitrogen gas pipe and a column equipped with a cooling device, a stirrer, a thermometer and a heater, and allowed to gradually warm. Propyleneglycol was prepared by reacting the mixture at 120 DEG C to 160 DEG C for 2 hours to 4 hours to obtain isosorbide-propylene glycol having a hydrogen in the hydroxyl group at both ends of the isosorbide substituted with a hydroxypropyl group.

Step 2: Preparation of prepolymer

66.5.8 g of terephthalic acid, 43.55 g of cyclohexanedicarboxylic acid, 36.55 g of adipic acid, 468.9 g of neopentyl glycol, 24.8 g of ethylene glycol, 22.55 g of 1,4-butylene glycol, 1 g of isosorbide- And 3.2 g of monobutyltin oxide (Bitti-300) as a catalyst were placed in a five-necked flask containing a nitrogen gas pipe and a column equipped with a cooling device, a stirrer, a thermometer and a heater, and the temperature was gradually raised. When the temperature of 120 ° C to 160 ° C is reached, the condensed water is flowed out. From this time, while maintaining the glycol in the condensed water, the temperature is raised to about 240 ° C to 250 ° C. Then, 1.3g of tributylphosphite is added, 33 mg KOH / g, an acid value of 4 mg KOH / g, a viscosity of 5,000 cPs (Brookfield viscosity at 175 ° C) and a number average molecular weight of 2,000.

Step 3: Production of polyester resin

1,200 g of the prepolymer prepared in the second step, 130.6 g of trimellitic anhydride and 20.7 g of adipic acid were placed in a five-necked flask containing a nitrogen gas pipe and a cooling device equipped with a stirrer, a thermometer and a heater, , The reaction temperature was maintained at 175 ° C to 205 ° C, and the reaction was carried out while removing the condensed water. Finally, in order to increase the degree of polymerization of the polyester resin, condensed water and unreacted materials that have not been extracted in polyester resin are removed using nitrogen excess or reduced pressure (50 to 200 mmHg), and 4.9 g of ethyltriphenylphosphonium bromide is charged To prepare a polyester resin having desired properties. The resulting final polyester resin had an acid value of 52 mgKOH / g, a viscosity of 3,300 cPs (Brookfield viscosity at 200 ° C), a glass transition temperature of 58 ° C and a number average molecular weight of 3,600.

[Example 4-1]

The amount of adipic acid used was changed from 35.55 g to 24.3 g, the amount of ethylene glycol used was changed from 24.8 g to 16.8 g, the amount of 1,4-butylene glycol was changed from 22.5 g to 18.9 g, the amount of isophorone- Except that the amount of glycol used was changed from 210 g to 260 g and the amount of trimellitic anhydride used was changed from 130.6 g to 145.8 g and the amount of adipic acid was changed from 20.7 g to 0 g in the polyester resin production step, A polyester resin was prepared in the same manner as in Example 3-1. The resulting final polyester resin exhibited an acid value of 50 mgKOH / g, a viscosity of 3,000 cPs (Brookfield viscosity at 200 ° C), a glass transition temperature of 59 ° C and a number average molecular weight of 3,900.

[Comparative Example 1-1]

Step 1: Preparation of prepolymer

A mixture of 831 g of terephthalic acid, 16.62 g of isophthalic acid, 26.13 g of cyclohexanedicarboxylic acid, 84.62 g of adipic acid, 521.0 g of neopentyl glycol, 31 g of ethylene glycol, 22.55 g of 1,4-butylene glycol and 10 g of monobutyltin oxide ) Was placed in a 5-necked flask containing a nitrogen gas pipe and a column equipped with a cooling device, a stirrer, a thermometer and a heater, and the temperature was gradually raised. When the temperature of 120 ° C to 160 ° C is reached, the condensed water is flowed out, and the temperature is raised to about 240 ° C to 250 ° C while controlling the glycol in the condensed water to give a hydroxy value of 40 mgKOH / g and an acid value of 5 mgKOH / g To prepare a prepolymer having a number average molecular weight of 2,000.

Step 2: Production of polyester resin

1,200 g of the prepolymer prepared in the first step, 129.6 g of trimellitic anhydride and 30.6 g of adipic acid were placed in a five-necked flask containing a nitrogen gas pipe and a cooling device equipped with a stirrer, a thermometer and a heater, , And the reaction was carried out while maintaining the temperature of the reaction product at 175 to 205 DEG C and removing the condensed water.

Finally, in order to increase the degree of polymerization of the polyester resin, condensed water and unreacted materials not extracted in the polyester resin are removed using nitrogen excess or reduced pressure (50 to 200 mmHg), and 5.6 g of ethyltriphenylphosphonium bromide is charged To prepare a polyester resin. The resulting final polyester resin exhibited an acid value of 53 mgKOH / g, a viscosity of 3,500 cPs (Brookfield viscosity at 200 ° C), a glass transition temperature of 54 ° C and a number average molecular weight of 2,800.

[Comparative Example 2-1]

The amount of terephthalic acid used is changed from 831 g to 847.6 g, the amount of isophthalic acid used is changed from 16.62 g to 0 g, the amount of adipic acid used is changed from 84.62 g to 83.93 g, the amount of neopentyl glycol used is changed from 521 g to 547 g, Was changed from 31 g to 15.5 g and the amount of 1,4-butylene glycol was changed from 22.55 g to 18.9 g. The amount of trimellitic anhydride used was changed from 129.6 g to 146.3 g in the polyester resin production step, A polyester resin was prepared in the same manner as in Comparative Example 1-1 except that the amount of the pin acid was changed from 30.6 g to 0 g. The resulting final polyester resin had an acid value of 52 mgKOH / g, a viscosity of 3,600 cPs (Brookfield viscosity at 200 ° C), a glass transition temperature of 53 ° C and a number average molecular weight of 2,700.

[Comparative Example 3-1]

The amount of terephthalic acid used was changed from 831 g to 847.6 g, the amount of adipic acid used was changed from 84.62 g to 79.6 g, the amount of ethylene glycol was changed from 31 g to 0 g, and the amount of trimellitic anhydride A polyester resin was prepared in the same manner as in Comparative Example 1-1 except that the amount of adipic acid used was changed from 129.6 g to 136.5 g and the amount of adipic acid was changed from 30.6 g to 18.7 g. The resulting final polyester resin had an acid value of 54 mgKOH / g, a viscosity of 3,300 cPs (Brookfield viscosity at 200 ° C), a glass transition temperature of 52 ° C and a number average molecular weight of 2,600.

The amounts of reactants used in Examples 1-1 to 4-1 and Comparative Examples 1-1 to 3-1 and the physical properties of the polyester resin thus prepared are shown in Table 1 below.

1: Ethyltriphenylphosphonium bromide: an additive that increases the reaction rate when a polyester resin is cured with an epoxy curing agent

2: 0.1 N-KOH methanol solution was used to measure the acid value.

3: The viscosity was measured at 200 ° C using a Brookfield viscometer (Brookfield CAP 2000 + Viscosmeter).

4: Number average molecular weight was measured by gel permeation chromatography (GPC) analysis.

5: The glass transition temperature was measured using a differential scanning calorimeter (DSC).

Preparation of Powder Coatings

[Example 1-2]

60 parts by weight of the polyester resin prepared in Example 1-1, 40 parts by weight of an epoxy resin (YD-013K, equivalent weight 800, National Kagaku KK) as a curing agent, 0.5 parts by weight of a pinhole inhibitor (Benzoin, Samchun) (R-902 +, Dupont-Titan) as a white pigment and 50 parts by weight of barium sulphate (BSN-OF) as an extender pigment (PV-5, Worlee) , Gemme) were uniformly mixed and then pulverized. Thereafter, the powder was dispersed through a high temperature extruder, and the solidified particles were again pulverized through a mixer, and a powder coating having a particle size of 120 μm or less was prepared through sieving.

[Examples 2-2, 3-2, 4-2 and Comparative Examples 1-2, 2-2, 3-2]

Except that the kinds of polyester resins were changed to the polyester resins prepared in Examples 2-1, 3-1 and 4-1 and Comparative Examples 1-1 and 2-1 and 3-1, respectively, Powder coatings were prepared in the same manner as in 1-2.

The compounding weight ratios of the powder coating materials of Examples 1-2 to 4-2 and Comparative Examples 1-2 to 3-2 are shown in Table 2 below.

Manufacture of coating film specimens

[ Example  1-3]

The powder coating material prepared in Example 1-2 was applied to a 0.6 mm thick steel sheet pretreated with zinc phosphate and cured at 160 ° C for 15 minutes and at 170 ° C for 10 minutes to obtain a coating film thickness of 90 ° A 10 ㎛ coating film specimen was prepared.

[ Example  2-3, 3-3, 4-3, and Comparative Example  1-3, 2-3, 3-3]

The powder coating materials prepared in Examples 2-2, 3-2 and 4-2 and Comparative Examples 1-2 and 2-2 and 3-2 were used instead of the powder coating materials, The same procedure as in Example 3 was repeated to prepare a coating film sample.

The physical properties of the prepared coating film samples were measured by the following methods.

<Leveling Evaluation Method>

The coating film specimen was visually observed. The smaller the curvature of the coating film specimen observed visually, the better the leveling.

<Pinhole evaluation method>

The thickness of the pinhole was measured using a thickness gauge. The larger the pinhole thickness, the better.

<Gloss Evaluation Method>

According to KSM ISO 2813, the gloss level of the coating was confirmed by using a gloss meter. The higher the value, the better the gloss and the better.

<Adhesiveness Evaluation Method>

In accordance with KSM ISO 2409, 100 grooves were formed on the coating film specimen at a distance of 1 mm x 1 mm with a constant force and attached with glass tape. After a certain time, the glass tape was peeled off and measured.

<Flexibility Evaluation Method>

In accordance with ASTM E 643-09, a certain force was applied to the pin axis on the opposite side of the coating sample using an Erichsen instrument to confirm the depth of penetration (mm) just before the crack occurred , And the higher the value, the better the flexibility.

<Flexibility Evaluation Method>

In accordance with KSM ISO 6860, when a coating film sample was folded in 3/8 inch by using a bending device, it was visually confirmed whether a crack occurred in the coating film sample.

○: When cracks did not occur

X: When a crack occurs

&Lt; Impact evaluation method &

According to KSM ISO 6272-1, a weight of 1 kg was dropped from a fixed stand of 50 cm and 20 cm height to visually check whether a crack occurred in the coating film specimen. The higher the drop height that can cause cracking, .

&Lt; Evaluation method of stain resistance &

As a pollution resistance test using magic as a pollutant, magic was applied to a coating film specimen with a constant force. After 24 hours, a soft cloth was appropriately buried with alcohol to visually confirm the degree of being visually observed. The higher the value, Staining property.

&Lt; Evaluation method of solvent resistance &

After the coating film samples were settled in xylene solvent for 24 hours, the peeling and luster of the coating film samples were checked over time.

<Evaluation method of alkali resistance>

According to ASTM D 1308-2, the coating film specimens were precipitated in a 5% NaOH solvent for 72 hours, and after a lapse of a certain time, the peeling and glossiness of the coating film were confirmed.

<QUV test>

(UV-B313) was irradiated onto the coating film specimen for a predetermined period of time and a cycle using a QUV instrument according to ASTM G 53-88, and the gloss and color difference were checked. The higher the gloss value, the better the weather resistance, The lower the value, the better the weather resistance.

<Storage stability evaluation method>

The degree of agglomeration or aggregation of the powder coating material was visually confirmed while storing the powder coating material in a high temperature environment of 40 캜 for 6 hours. The smaller the aggregation or aggregation of the powder coating material, the better the storage stability.

◎: Almost no agglomeration or aggregation of powder coating

○: Coagulation or aggregation of powder coating slightly

X: Plenty of aggregate or aggregation of powder coating

The physical properties of the measured film specimens are shown in Table 3 below.

As shown in Table 3, powder coating materials were prepared using the polyester resins prepared in Examples 1-1 to 4-1 and Comparative Examples 1-1 to 3-1, respectively, and cured under the same curing conditions As a result of comparing physical properties of the coated film specimen, both leveling, pinhole and gloss were good in appearance.

In terms of mechanical properties, Examples 1-3 to 4-3 according to the present invention had excellent flexibility and excellent flexibility of 7 mm or more, while Comparative Examples 1-3 and 3-3 had flexibility of 4 To 5 mm, and the flexibility was also poor.

In terms of chemical resistance, the coating samples of Examples 1-3 to 4-3 according to the present invention had a stain resistance of about 2 to 3 higher than the coating samples of Comparative Examples 1-3 to 3-3, And the alkali resistance was all good.

Comparing the QUV performance tests, the gloss of the coating samples of Examples 1-3 to 4-3 according to the present invention was as good as 63% to 66%, while the coating samples of Comparative Examples 1-3 to 3-3 The chromaticity of the coating films of Examples 1-3 to 4-3 according to the present invention was lower than that of the coating films of Comparative Examples 1-3 to 3-3, Was better.

From the viewpoint of storage stability, the coating specimens of Examples 1-3 to 4-3 according to the present invention were also superior to the coating specimens of Comparative Examples 1-3 to 3-3.

Claims (16)

A repeating unit derived from a diol component including an anhydride alcohol-alkylene glycol which is an adduct obtained by reacting a terminal hydroxyl group of an alcohol with no anhydride with an alkylene oxide; And a repeating unit derived from a polyfunctional acid component. The polyester resin of claim 1, wherein the anhydrosugar alcohol is selected from the group consisting of isosorbide, isomannide, isoidide, and mixtures thereof. The polyester resin according to claim 1, wherein the alkylene oxide is ethylene oxide, propylene oxide, or a mixture thereof. The polyester resin according to claim 1, wherein the diol component further comprises a diol compound other than an alcohol-free alcohol-alkylene glycol. The polyester resin according to claim 4, wherein the diol compound other than the alcohol-free alcohol-alkylene glycol is an aliphatic diol, an alicyclic diol, an aromatic diol or a combination thereof. 6. The composition of claim 5, wherein the aliphatic diol is a linear or branched aliphatic diol having from 2 to 8 carbon atoms; An alicyclic diol having 5 to 20 carbon atoms in which the alicyclic diol contains 1 to 4 5-atomic ring structures or 6-atomic ring structures; Wherein the aromatic diol is an aromatic diol having 6 to 20 carbon atoms and containing from 1 to 4 aromatic ring structures. 6. The composition of claim 5 wherein the aliphatic diol is selected from the group consisting of ethylene glycol, diethylene glycol, triethylene glycol, 1,3-propanediol, 1,2-propanediol, 1,4-butanediol, Butanediol, 2,2-dimethyl-1,3-propanediol, pentanediol, hexanediol, heptanediol, and combinations thereof;
Wherein the alicyclic diol is 1,4-cyclohexanediol, 1,3-cyclohexanediol, 1,2-cyclohexanediol, 1,4-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, Cyclohexanedimethanol, cyclohexanedimethanol, tetramethyl cyclobutanediol, tricyclodecane dimethanol, adamantanediol, isosorbide, and combinations thereof;
Wherein the aromatic diol is selected from the group consisting of bisphenol A, 4,4'-dihydroxy-diphenylsulfone, 4,4'-biphenol, hydroquinone, 4,4'-dihydroxy- Phenoxy) phenol, bis (4-hydroxyphenyl) sulfide, and combinations thereof. 2. The composition of claim 1, wherein the diol component comprises from 1 to 90 mol% of anhydrosugar alcohol-alkylene glycol and from 10 to 99 mol% of a diol compound other than anhydrosugar alcohol-alkylene glycol, based on 100 mol% Polyester resin. The polyester resin according to claim 1, wherein the polyfunctional acid component is a divalent acid, a trivalent acid, or a mixture thereof. The polyester resin according to claim 9, wherein the dicarboxylic acid is selected from the group consisting of aromatic dicarboxylic acids having 8 to 14 carbon atoms, aliphatic dicarboxylic acids having 4 to 12 carbon atoms, and combinations thereof. 10. The composition of claim 9, wherein the dicarboxylic acid is selected from the group consisting of terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid, diphenyldicarboxylic acid, cyclohexanedicarboxylic acid, phthalic acid, sebacic acid, succinic acid, maleic acid, fumaric acid, Tartaric acid, and combinations thereof, wherein the trivalent acid is trimellitic acid or an anhydride thereof. (1) reacting an anhydrosugar alcohol with an alkylene oxide to prepare an adduct free alcohol-alkylene glycol;
(2) preparing a prepolymer by reacting the diol component containing anhydrosugar alcohol-alkylene glycol prepared in the step (1) with a polyvalent acid component; And
(3) preparing a polyester resin by reacting the prepolymer prepared in the step (2) with a polyvalent acid component;
By weight based on the total weight of the polyester resin. The process according to claim 12, wherein the prepolymer obtained in step (2) has a hydroxy value of 30 to 40 mg KOH / g, an acid value of 1 to 10 mg KOH / g, a viscosity of 4,000 to 6,000 cPs And a number average molecular weight of 1,500 to 2,500. The polyester resin according to claim 12, wherein the polyester resin obtained in the step (3) has an acid value of 40 to 60 mgKOH / g, a viscosity of 2,000 to 6,000 cPs (200 占 폚 Brookfield viscosity), a glass transition temperature of 55 to 100 占 폚 And a number average molecular weight of 3,000 to 5,000. A powder coating composition comprising a polyester resin according to any one of claims 1 to 11 and a curing agent. The powder coating composition according to claim 15, wherein the curing agent is an epoxy resin curing agent.