KR100526484B1 - Polyester resin for powder coating having excellent weather resistance and stain resistance and powder coating composition containing the same - Google Patents

Abstract

The present invention relates to a polyester resin for powder coating having excellent weather resistance and fouling resistance, and a powder coating composition containing the same. More specifically, two kinds of very different weather and fouling resistance having carboxyl group and hydroxyl group at the same time It relates to a polyester resin having a functional group of and a powder coating composition containing the same. The resin may be mixed with the powder coating composition to maximize weather resistance and stain resistance, and may also obtain good results in leveling, storage stability, and mechanical properties.

Description

Polyester resin for powder coating having excellent weather resistance and stain resistance and powder coating composition containing the same

The present invention relates to a polyester resin for powder coating having excellent weather resistance and fouling resistance, and a powder coating composition containing the same. More specifically, two kinds of very different weather and fouling resistance having carboxyl group and hydroxyl group at the same time It relates to a polyester resin having a functional group of and a powder coating composition containing the same. The resin may be mixed with the powder coating composition to maximize weather resistance and stain resistance, and may also obtain good results in leveling, storage stability, and mechanical properties.

Conventional powder coating resins can be classified into several types according to their use. Firstly, in case of indoors, acid polyester resin and epoxy curing agent are mainly used. Second, hydroxy polyester resin and urethane curing agent are used for P.C.M coating which requires excellent processability. Third, weather resistance is required. For outdoor applications, a system using triglycidyl isocyanurate as an acidic polyester resin and curing agent was mainly used.

Globally, the first case described above has very poor weather resistance, so there is no use history for outdoor use, and the second case has an adequate level of weatherability and pollution resistance depending on the formulation, but the use performance is insufficient. In conclusion, the third case is most applied to outdoor weather-resistant resins and paints that are used the most in the world.

In the case of the conventional outdoor weather-resistant polyester resin, only the carboxyl group is used as a functional group, and most of the raw materials used are general weather-resistant raw materials, and triglycidyl isocyanurate is used as a curing agent. In the case of the used paint, the mechanical strength and adhesiveness are excellent, but the rust resistance and the chemical resistance are inferior, and in particular, the stain resistance and the weather resistance tend to be significantly lower than those of the fluorine paint and the acrylic paint. Therefore, the paint using the resin has been applied only to extremely limited applications, and there is little application of aluminum window frames or panels.

In the present invention, in order to compensate for the above-mentioned disadvantages, the resin has two different functional groups at the ends that balance the thermal flowability of the resin, the crosslinking, the reaction rate, the melt viscosity of the resin, the glass transition temperature, the softening point, and the like. Resin was prepared to make powder coating having excellent appearance, chemical resistance, and heat resistance, particularly weather resistance and stain resistance.

Existing weatherable powder coating resins mainly use aromatic polyacids as predominant species, which may have excellent storage and mechanical properties, but are poor in weatherability. Glycol raw materials containing alicyclic polyacids and functional groups of 3 or more to improve weather resistance In the case of using the resin, the weather resistance at the time of coating application was excellent, but the leveling was poor. On the contrary, when reducing or not using a glycol raw material having three or more functional groups to improve leveling, leveling is improved but weather resistance is deteriorated.

In addition, when the glass transition temperature of the resin and the coating film is increased by using a raw material having a large molecular weight in order to improve the fouling resistance, the fouling resistance is good but the coating film is too hard, resulting in poor mechanical properties and leveling.

However, in the present invention, a raw material and a resin structure having the following characteristics were selected to improve the above-described problems of fouling resistance and weather resistance.

In order to improve weather resistance, hexahydrophthalic anhydride with low free electron generation, 1,4-cyclo hexadicarboxylic acid, and isophthalic acid having a carboxyl group at an iso position where free electrons do not move are introduced as an acid. Neopentyl glycol without hydrogen in the beta position, and trimethyl propane having a functional group that can physically prevent the penetration of UV wavelength or moisture by increasing the crosslinking density of the resin itself must be introduced.

In order to improve the stain resistance, trimethylol propane having a trifunctional group having a short main chain and side chain length and constraining molecular motion of the polymer must be used as described in the weather resistant raw material to increase the degree of crosslinking of the resin itself.

In the resin structure, a polyester resin having two different functional groups that can fully utilize the properties of the curing agent was selected. In this case, two kinds of curing agents are used as curing agents, that is, a curing agent having a hydroxyl group or an epoxy group having a large number of functional groups and a large molecular weight. The urethane curing agent is used to minimize the molecular motion of the coating film while increasing the crosslinking density of the coating film, so that the gap between the main chain and the main chain yarn or the side chain and the side chain is reduced, that is, even when dirty substances such as carbon come into contact with the surface. Because of the low contact area, the contact area is reduced, making it difficult to form interactions by van der Waals forces or hydrogen bonds. Such a low mobility coating film can easily remove contaminants and improve weather resistance at the same time.

Resin and paint prepared by the above method was able to maximize the stain resistance and weather resistance, and also obtained excellent results in excellent storage stability and leveling properties, and mechanical properties.

Accordingly, an object of the present invention is to provide a polyester resin having two different functional groups at the terminal having excellent weather resistance and stain resistance as described above.

Another object of the present invention to provide a powder coating composition comprising the polyester resin.

The polyester resin of the present invention for achieving the above object is (1) 49 to 68 parts by weight of one or more divalent or more aromatic carboxylic acids, and one or more divalent or more alicyclic or aliphatic acids having 6 or less carbon atoms in the main chain. 30 parts by weight to 38 parts by weight of one or more divalent glycols having 4 or less parts by weight and shorter side chains and two or more carbon atoms in the main chain, and 1.0 parts by weight or less of one or more tin catalysts to 2 to 8 parts by weight of trimethylol propane. Was prepared in an alcohol / acid equivalent ratio of 1.0 to 1.3 to produce a prepolymer having a hydroxyl value of 30 to 80 and a melt viscosity of 12 to 50 poise (175 ° C. (2) 1 to 15 parts by weight of isophthalic acid, 1 to 10 parts by weight of hexahydrophthalic anhydride, and 0.1 weight of one or more tin catalysts in 100 parts by weight of the prepolymer resin prepared in the first step reaction. Reaction is carried out at 210-220 degreeC by adding below-parts It is made on. The resin has a hydroxyl value of 5 to 40 and an acid value of 10 to 50, and a terminal having an average number of functional groups of about 1.5 to 3 at the end of the resin having a melt viscosity of 15 to 50 poise (200 DEG C, I. C. eye viscometer). Has two different functional groups.

Powder coating composition of the present invention for achieving the above another object is 29 to 68 parts by weight of the polyester resin, 1 to 23 parts by weight of a curing agent having a hydroxyl or epoxy group equivalent of 70 to 600, -NCO equivalent 250 to 300 It consists of 1-10 weight part of phosphorus urethane hardening agents, 30-33 weight part of titanium dioxide, 15 weight part or less of extender pigments, and 7 weight part or less of other additives.

Looking at the present invention in more detail as follows.

The polyester resin according to the present invention is a one-step reaction for preparing a prepolymer having a hydroxyl value of 30 to 80 and a poly having two kinds of functional groups at terminals having a hydroxyl value of 5 to 40 and an acid value of 10 to 50. It is prepared by a two step reaction to prepare an ester resin.

In the one-step reaction, at least one divalent or higher aromatic, aliphatic, or alicyclic carboxylic acid must be used in order to have the proper glass transition temperature and weather resistance of the resin, and improve the weather resistance and fouling resistance by increasing the crosslinking density of the resin itself. In order to make trimethylol propane an essential ingredient, at least one divalent glycol should be used to improve leveling, weather resistance, chemical resistance, and the like.

In the two-stage reaction, in order to have excellent leveling, weather resistance, and glass transition temperature, a divalent or higher alicyclic hexahydro phthalic hydride must be used together with an appropriate amount of isophthalic acid having a bivalent cis structure. By adjusting the raw material selected in the steps 1 and 2 appropriately to prepare a resin having two different functional groups at the end, it is possible to have a superior weather resistance and stain resistance, leveling compared to the existing weather-resistant resin.

In the powder coating according to the present invention, a weathering curing agent having a hydroxyl or epoxy group and a urethane curing agent having an -NCO group are used in combination, and in this case, a basic composition of the powder coating having better weather resistance and contamination resistance is provided. As the curing agent used herein, a curing agent having a hydroxyl group or an epoxy group having an equivalent of 70 to 600 and a urethane curing agent having a -NCO equivalent of 250 to 350 were mainly used.

Next, the production steps of the resin used in the present invention will be described in more detail.

Step 1 manufacture

49 to 68 parts by weight of one or more divalent or more aromatic carboxylic acids, and one or more divalent or more alicyclic or aliphatic acids having 6 or less carbon atoms and 4 parts by weight or less of the main chain and short side chains 30 to 38 parts by weight of one or more divalent glycols having 2 or more carbon atoms, and 2 to 8 parts by weight of trimethylol propane, 1.0 part by weight or less of the tin catalyst to 1.0 to 1.3 in the equivalent ratio of alcohol / acid. The reaction is carried out to about 240 ~ 250 ℃ while removing the condensed water under the introduction of nitrogen gas. At this time, the hydroxyl value of the prepared primary prepolymer was 30 to 80 mg KOH / g, the acid value was 5 to 30 mg KOH / g, and the melt viscosity was 12 to 50 poise (175 ° C. The average molecular weight is about 1500 to 4000.

2 step manufacturing

1 to 15 parts by weight of isophthalic acid, 1 to 10 parts by weight of hexahydrophthalic anhydride, and 0.1 or more parts of a tin catalyst were added to 100 parts by weight of the prepolymer resin prepared in the one-step reaction. The condensed water is removed while reacting at 210 to 220 ° C. under the injection of gas, and the condensed water or unreacted material that is not extracted by nitrogen excess or reduced pressure is sufficiently removed in order to maintain proper polymerization degree and molecular weight distribution in the final step. The acid value of the final resin obtained at this time is 10 to 50 mg KOH / g, the hydroxyl value of 5 to 40 mg KOH / g polyester resin having two different functional groups at the end, the melt viscosity is 15 to 50 poise (200 ℃, I. C. eye viscometer), the softening point is 115 to 125 ℃, the glass transition temperature is 55 to 75 ℃, the number average molecular weight is 1,500 to 5,000, the average number of functional groups at the resin end is about 1.5 to 3.

The divalent or higher aromatic carboxylic acid in the first step preparation is one selected from the group consisting of terephthalic acid, isophthalic acid, dimethyl isophthalic acid, phthalic anhydride, methyl tetrahydrophthalic anhydride, S.S-isophthalic acid, and tert-butyl isophthalic acid. The aliphatic or alicyclic carboxylic acids having 6 or less carbon atoms in the main chain may be used as succinic acid, adipic acid, azelaic acid, hexahydro phthalic anhydride, methyl-hexahydro phthalic anhydride, and 1,4-cyclohexane dicarboxylic acid. One or more types selected from the group consisting of can be used.

Bivalent glycols with short side chains include neopentyl glycol, ethylene glycol, propylene glycol, 2-butyl-2ethyl-1,3 propane diol, 1,3-butylene glycol, hydrogenated bisphenol-A, 1,6 1 type selected from the group consisting of -hexane diol, 1,4-cyclohexane dimethylol, 3-hydroxy-2,2-dimethyl propyl 3-hydroxy-2,2, -dimethyl propanoate, and diethylene glycol The above can be used.

On the other hand, in the physical property change according to the use ratio, aromatics in the first stage resin production must use 49 parts by weight or more, but when used less than the amount of alicyclic or glycol increases, the resin hardness and glass transition temperature is lowered, There exists a tendency for the storage property of and the hardness of a coating film to fall. Alicyclic or aliphatic must be used in an amount of 4 parts by weight or less. If this is exceeded, weatherability may be better, but other physical properties are the same as in the former. In addition, the glass transition temperature of the resin when used in excess of the amount of the aromatic used may be increased, but the reactivity in synthesis is too low and the mechanical properties may be inferior.

In the case of dihydric glycol having short side chains, the weather resistance and leveling of the paint is improved when it is used in excess of 38 parts by weight, but the crosslinking density of the resin itself is lowered, which lowers the fouling resistance and chemical resistance of the coating film. When the use of more than 8 parts by weight of trimethylol propane, the crosslinking density of the resin itself, the viscosity and the functional group ratio of the final resin are increased, so that the fouling resistance, heat resistance and chemical resistance of the coating film are improved, but the viscosity is too high. Difficult to select the raw materials in the two-stage reaction to produce resins having two different functional groups at the end, resulting in poor synthetic stability and rapid reactivity, resulting in poor leveling of the paint. And the synthetic stability is improved, but the crosslinking density of the resin itself and the functional group ratio of the final resin Too low, there is a problem that the fouling resistance, chemical resistance of the coating film falls. Therefore, it is not easy to select the raw material in the second step production in the resin production for achieving the object of the present invention outside the above range.

When using more than 15 parts by weight of isophthalic acid in the production of two-stage resin, the glass transition temperature is increased but the reactivity of the paint is increased.The leveling, weather resistance, and stain resistance are lowered, and when it is used by 1 part by weight or less, alicyclic or aliphatic Increasing the amount of weather resistance and leveling is good, but the glass transition temperature of the resin is lowered, there is a problem in the storage stability of the paint. When hexahydrophthalic anhydride is used in excess of 10 parts by weight, the leveling and weather resistance are improved, but the glass transition temperature of the resin is lowered, resulting in poor storage stability, mechanical properties, or stain resistance of the paint. The transition temperature is high but the leveling and weather resistance is poor.

In the case of the acid value and hydroxyl value of the final resin, when the acid value is 10 or less and the hydroxyl value is 5 or less, the curing property is too slow to be inadequate for the powder coating such as poor mechanical properties, chemical resistance, etc., and the acid value is 10 or less. When the hydroxyl value is 40 or more and the acid value is 50 or more and the hydroxyl value is 5 or less, the synthetic stability is lowered. If the hydroxyl value is high, the stain resistance is improved, but the weather resistance is decreased, while if the acid value is high, the weather resistance is improved, but the pollution resistance is decreased. The opposite results. When the acid value is 50 or more and the hydroxyl value is 40 or more, fouling resistance and weather resistance may be improved, but there is a problem in that the price of the paint is increased due to the decrease in the leveling and the increase of the amount of the curing agent because the synthetic stability is poor and the reactivity of the paint is too fast.

Therefore, in the present invention, the resin should be prepared within the range satisfying the conditions of steps 1 and 2 to have a glass transition temperature, an appropriate level of melt viscosity, an acid value, and a hydroxyl value without any problems in storage stability, and also excellent pollution resistance. It can have performance and weather resistance.

On the other hand, the powder coating composition according to the present invention is 29 to 68 parts by weight of the polyester resin produced by the above method, 1 to 23 parts by weight of a curing agent having a hydroxyl or epoxy group equivalent of 70 to 600, -NCO equivalent 250 to 300 1 to 10 parts by weight of a phosphorus urethane curing agent 30 to 33 parts by weight of titanium dioxide, 15 parts by weight or less of extender pigments, and other additives (curing accelerators, ultraviolet absorbers, Hals, antioxidants, flow improvers, and / or pinhole inhibitors, etc.) ) It is composed of 7 parts by weight or less.

In the powder coating composition of the present invention, the resin is PTI-810 ( triglycidyl isocyanate ), PTI-910 as a curing agent using a resin prepared by the above method and having a hydroxyl or epoxy group having an equivalent of 70 to 600. ( Diglycidyl terephthalate , Ciba-Geigy Co., Ltd. brand name), X.L - 552 ( beta hydroxy akylamide, Ems Corporation: brand name), G.M.A 300 ( glycidyl methacrylate, equivalent: 300 ), Sipi-550 ( glycidyl methacrylate (equivalent: 550) , Wallysa : trade name), and non--1530 ( epsilon caprolactam blocking isocyanate ) as a urethane curing agent having a -NCO equivalent of 250 to 350 , biepeu -1540 (urea thione, hyul, Inc.: Product Name), 24-2450 (epsilon -caprolactam block Ian King isobutyl carbonate), 24-2400 (epsilon -caprolactam block Ian King isopropyl carbonate, Cargill Corporation: trade name), such as a resin equivalent ratio It was adjusted to use. Titanium dioxide is Al-902, -960 (Dupont), C.R-80, -90 (Ishihara), etc., and as a extender pigment, barium sulfate system, aluminum hydroxide system, silicon-based oil -5 H. rain ( aluminum oxalate , Mountain company), O.L-104 ( silicone system , Martinsberg company), etc. can be used, and among other additives, the curing accelerator, organic tin such as dibutyl tin dilaurate Compounds, triphenyl phosphine (Hoco Corp.), quaternary ammonium salts such as tetrabutyl ammonium bromide, imidazoles, and basket 4101 (butylchlorotin dihydroxide , Acto Chemical Co., Ltd.); , 1130 ( 2-hydroxyphenylbenzotriazole , Shivagaigi Co., Ltd.), UV-1164 (Sitac Co., Ltd.), etc., and Hals is composed of thinubin-114, 292, 662, 700 ( NCH3 and phenolic antioxidant the mixture, including at least Ciba Geigy Co.), Sander probe -3055 (between Alismataceae), acid Inhibitor is monovalent Knox -1076 (mono fern relational entities phenolic antioxidants), -1010, - P S 800 - P S 802, -168 monovalent Force (organo phosphite entities oxidant, at least Ciba Geigy Co.) Examples of the flow improver include Modaflow I ( acrylic based , Monsanto), FV-5 ( acrylic ), FV-88 (Wallley), acronal -4-F ( polysilaxone acrylate , BASF Co., Ltd.) As a pinhole inhibitor, benzoin ( 2-hydroxy-1,2-diphenylethanone , BASF Co., Ltd.), A.D.D-900, -902 ( polyacrylate , more than Wally) , Lanco Wax P. 132-Di ( polyethylene wax , Langer), Spinol-104 (Air Products) and the like were used.

In the use of the curing agent, the use of less than the amount of the use is less reactivity, mechanical properties and fouling resistance is lowered, when used in excess of the amount of curing agent increases the pollution resistance can be improved but the chemical resistance, etc. due to the effect of unreacted curing agent or Or there is a problem that the leveling is worse because the reactivity is too fast. Therefore, the amount of use should always be used in the same equivalence ratio against the acid value and hydroxyl value of the resin.

The paints prepared at the above compounding ratio are mixed evenly in a mixer, melt-dispersed at 90-120 ° C. in a disperser, and then ground to prepare powder coatings of appropriate particles.

The powder coating prepared as described above has excellent leveling, stain resistance and weather resistance due to excellent thermal flowability and high crosslink density formation during curing.

Hereinafter, the effects of the present invention will be described in more detail with reference to Examples and Comparative Examples, but the scope of the present invention is not limited to the following Examples.

Example 1

Phase 1 manufacturing

552.2 parts by weight of isophthalic acid, 359.3 parts by weight of neopentyl glycol, 18.7 parts by weight of trimethylol propane, and 0.95 parts by weight of a packet 4101 were placed in a four-necked flask equipped with a nitrogen gas pipe and a cooling device, a stirrer, a thermometer, and a heater. Increase the temperature. When the temperature reaches 120 to 160 ° C., condensed water flows out. From this time, the temperature is reacted to about 240 to 245 ° C. while maintaining the glycol content in the condensed water to prepare a primary prepolymer. At this time, the hydroxyl value of the produced resin was 43 mg KOH / g, the acid value was 20 mg KOH / g, and the viscosity was 20 poise (175 ° C I. C. eye viscometer).

2-step manufacturing

45.89 parts by weight of isophthalic acid, 18.6 parts by weight of hexahydrophthalic anhydride, and 0.436 parts by weight of a packet 4101 were added to the first stage prepolymer, and condensed water was removed while maintaining the reaction at 210 to 220 ° C. Finally, in order to increase the degree of polymerization of the resin, unextracted condensed water or unreacted material in the resin is removed using excess nitrogen or reduced pressure (150 mmHg or less) to prepare a resin having a desired physical property.

At this time, the final resin prepared was acid value = 30 mg KOH / g, hydroxyl value = 23 mg KOH / g, viscosity = 25 poise (200 ℃ I. C. eye viscometer), softening point = 121 ℃, number average molecular weight = 3100 Has

Example 2

Phase 1 manufacturing

Using 533 parts by weight of isophthalic acid, 362 parts by weight of neopentyl glycol, 19 parts by weight of trimethylol propane, and 0.91 parts by weight of a basket 4101, the hydroxyl value was 65 mg KOH / g, an acid value of 12 mg KOH / g and a viscosity of 16 poises (175 DEG C. I. Viscometer) are prepared.

2-step manufacturing

59 parts by weight of isophthalic acid, 24 parts by weight of hexahydrophthalic anhydride, and 0.44 parts by weight of 4101 of a packet were added to the entire prepolymer prepared in step 1, and reacted in the same manner as in the step 2 preparation of Example 1 to obtain a resin of desired physical properties. To prepare.

The final resin prepared was acid value = 40 mg KOH / g, hydroxyl value = 38 mg KOH / g, viscosity = 20 poise (200 ℃ I. C. eye viscometer), softening point = 118 ℃, number average molecular weight = 3300 It has physical properties.

Example 3

Phase 1 manufacturing

Isophthalic acid, 37 parts by weight of adipic acid, 337 parts by weight of neopentyl glycol, 44 parts by weight of trimethylol propane, 0.938 parts by weight of a packet were reacted in the same manner as in the first step preparation of Example 1 to hydroxyl. A prepolymer having a value of 44 mg KOH / g, an acid value of 15 mg KOH / g, and a viscosity of 17 poises (175 ° C I. C. Eye Viscometer) is prepared.

2-step manufacturing

43 parts by weight of isophthalic acid, 18 parts by weight of hexahydrophthalic anhydride, and 0.44 parts by weight of 4101 of a packet were added to the entire prepolymer prepared in step 1, and reacted in the same manner as in the step 2 preparation of Example 1 to obtain a resin of desired physical properties. To prepare.

The final resin produced was acid value = 20 mg KOH / g, hydroxyl value = 28 mg KOH / g, viscosity = 20 poise (200 ℃ I. C. eye viscometer), softening point = 117.3 ℃, number average molecular weight = 2950 It has physical properties.

Example 4

Phase 1 manufacturing

503 parts by weight of isophthalic acid, 46.6 parts by weight of hexahydrophthalic anhydride, 349 parts by weight of neopentyl glycol, 30 parts by weight of trimethylol propane, and 0.929 parts by weight of a packet 4101 were reacted in the same manner as in the first step preparation of Example 1. A prepolymer having a hydroxyl value of 46 mg KOH / g, an acid value of 18 mg KOH / g, and a viscosity of 19 poises (175 ° C.

2-step manufacturing

57 parts by weight of isophthalic acid, 12 parts by weight of 1,4-cyclohexanedicarboxylic acid, and 0.44 parts by weight of a packet 4101 were added to the entire prepolymer prepared in step 1, and reacted in the same manner as in the step 2 preparation of Example 1. To prepare a resin of the desired physical properties.

The final resin prepared was acid value = 30 mg KOH / g, hydroxyl value = 24 mg KOH / g, viscosity = 19 poise (200 ℃ I. C. eye viscometer), softening point = 120 ℃, number average molecular weight = 3150 It has physical properties.

Example 5

Phase 1 manufacturing

507 parts by weight of isophthalic acid, 53 parts by weight of 1,4-cyclohexanedicarboxylic acid, 356 parts by weight of neopentyl glycol, 25 parts by weight of trimethylol propane, and 0.940 parts by weight of a basket 4101, the same as in the first step preparation of Example 1. The reaction was carried out to prepare a prepolymer having a hydroxyl value of 43 mg KOH / g, an acid value of 16 mg KOH / g, and a viscosity of 17.5 poise (175 ° C.

2-step manufacturing

45 parts by weight of isophthalic acid, 12.5 parts by weight of hexahydrophthalic anhydride, and 0.44 parts by weight of a packet 4101 were added to the entire prepolymer prepared in step 1, and reacted in the same manner as in the step 2 preparation of Example 1 to obtain desired physical properties. Prepare a resin.

The final resin prepared was acid value = 25 mg KOH / g, hydroxyl value = 23 mg KOH / g, viscosity = 18 poise (200 ℃ I. C. eye viscometer), softening point = 119 ℃, number average molecular weight = 3200 It has physical properties.

Comparative Example 1

Phase 1 manufacturing

561 parts by weight of isophthalic acid, 260 parts by weight of neopentyl glycol, 113 parts by weight of trimethylol propane, and 0.934 parts by weight of a basket 4101 were reacted in the same manner as in the first step preparation of Example 1, and the hydroxyl value was 50 mg KOH / g, an acid value of 25 mg KOH / g, and a viscosity of 48 poise (200 ° C.

2-step manufacturing

44.8 parts by weight of isophthalic acid, 18 parts by weight of hexahydrophthalic anhydride, and 0.44 parts by weight of a packet 4101 were added to the entire prepolymer prepared in step 1, and reacted in the same manner as in the step 2 preparation of Example 1 to obtain a resin of desired physical properties. To prepare.

The final resin produced was acid value = 25 mg KOH / g, hydroxyl value = 23 mg KOH / g, viscosity = 67 poise (200 ℃ I. C. eye viscometer), softening point = 131 ℃, number average molecular weight = 4500 It has physical properties.

Comparative Example 2

Phase 1 manufacturing

Using 553 parts by weight of isophthalic acid, 367 parts by weight of neopentyl glycol, 13 parts by weight of trimethylol propane, and 0.933 parts by weight of a basket 4101, the hydroxyl value was 43 mg KOH / g, an acid value of 23 mg KOH / g, and a viscosity of 17 poises (175 DEG C. I. Viscometer) are prepared.

2-step manufacturing

67 parts by weight of isophthalic acid and 0.44 parts by weight of the packet 4101 were added to the entire prepolymer prepared in step 1 and reacted in the same manner as in the step 2 preparation of Example 1 to prepare a resin having a desired physical property.

The final resin prepared was acid value = 30 mg KOH / g, hydroxyl value = 23 mg KOH / g, viscosity = 23 poise (200 ℃ I. C. eye viscometer), softening point = 119 ℃, number average molecular weight = 3400 It has physical properties.

Comparative Example 3

Phase 1 manufacturing

539 parts by weight of isophthalic acid, 375 parts by weight of neopentyl glycol, and 0.934 parts by weight of a packet 4101 were reacted in the same manner as in the first step preparation of Example 1, and the hydroxyl value was 45 mg KOH / g, and the acid value was 12 mg. KOH / g, the viscosity is 15 poise (175 ℃ I. C. eye viscometer) to prepare a prepolymer.

2-step manufacturing

75.4 parts by weight of isophthalic acid, 4.6 parts by weight of hexahydrophthalic anhydride, 2.0 parts by weight of trimellitic acid anhydride, and 0.44 parts by weight of a packet 4101 were added to the entire prepolymer prepared in step 1, and condensed while maintaining the reaction at 220 to 230 ° C. Remove the water. Finally, in order to increase the degree of polymerization of the resin, unextracted condensed water or unreacted material in the resin is removed using excess nitrogen or reduced pressure (150 mmHg or less) to prepare a resin having a desired physical property.

The final resin thus prepared had physical properties of acid value = 36 mg KOH / g, viscosity = 20 poise (200 ℃ I. C. eye viscometer), softening point = 117 ℃, number average molecular weight = 3400.

Comparative Example 4

Phase 1 manufacturing

442 parts by weight of isophthalic acid, 111 parts by weight of terephthalic acid, 330 parts by weight of neopentyl glycol, 35 parts by weight of ethylene glycol, 0.915 parts by weight of the packet were reacted in the same manner as in the first step preparation of Example 1 to obtain a hydroxyl value. A prepolymer having 43 mg KOH / g, an acid value of 9.7 mg KOH / g, and a viscosity of 30 poise (175 ° C I. C. Eye Viscometer) is prepared.

2-step manufacturing

59 parts by weight of isophthalic acid, 23 parts by weight of trimellitic anhydride and 0.44 parts by weight of a packet 4101 were added to the entire prepolymer prepared in step 1, and reacted in the same manner as in the second step preparation of Comparative Example 3 to obtain a resin of desired physical properties. To prepare.

The final resin thus prepared has physical properties of acid value = 38 mg KOH / g, viscosity = 55 poise (200 ℃ I. C. Viscometer), softening point = 134 ℃, number average molecular weight = 3500.

Comparative Example 5

Phase 1 manufacturing

515 parts by weight of isophthalic acid, 12.7 parts by weight of adipic acid, 321 parts by weight of neopentyl glycol, 5.7 parts by weight of ethylene glycol, 34 parts by weight of trimethylol propane, and 0.888 parts by weight of a packet 4101, the same as in the first step preparation of Example 1 The reaction was carried out to prepare a prepolymer having a hydroxyl value of 45 g KOH / g, an acid value of 10.4 mg KOH / g, and a viscosity of 35 poises (200 ° C. I. Viscometer).

2-step manufacturing

84 parts by weight of isophthalic acid, 30 parts by weight of hexahydro phthalic anhydride, and 0.44 parts by weight of a packet 4101 were added to the entire prepolymer prepared in step 1, and the reaction was carried out in the same manner as in the second step preparation of Comparative Example 3. To prepare a resin of physical properties.

The final resin thus prepared has physical properties of acid value = 60 mg KOH / g, viscosity = 47 poise (200 ℃ I. C. Viscometer), softening point = 125 ℃, number average molecular weight = 3700.

Comparative Example 6

Phase 1 manufacturing

510 parts by weight of isophthalic acid, 327 parts by weight of neopentyl glycol, 75 parts by weight of hydrogenated bisphenol A, and 0.913 parts by weight of a packet 4101 were reacted in the same manner as in the one-step preparation of Example 1, and the hydroxyl value was 50 g KOH / g, an acid value of 16.3 mg KOH / g, and a viscosity of 18 poises (200 ° C.

2-step manufacturing

77.2 parts by weight of isophthalic acid, 7.2 parts by weight of hexahydro phthalic anhydride, and 0.44 parts by weight of a packet 4101 were added to the first stage prepolymer, and reacted in the same manner as in the second step preparation of Comparative Example 3. Manufacture.

The final resin thus prepared had physical properties of acid value = 36 mg KOH / g, viscosity = 35 poise (200 ℃ I. C. eye viscometer), softening point = 132 ℃, number average molecular weight = 4100.

Comparative Example 7

Currently commercialized high weather resistance resin (N3314: manufactured by Korea Chemical) was used, wherein the acid value is 48 mg KOH / g, the number average molecular weight is 3400.

Comparative Example 8

A commercially available high weather resistance resin (CC2988: manufactured by U.C.B) was used, with an acid value of 35 mg KOH / g and a number average molecular weight of 2900.

Examples and Comparative Examples The resins were formulated in the composition shown in Table 1 below, and powder coating was prepared using the coating method described above, followed by 200 ° C. × 10 on a zinc phosphate coated steel plate or chromate treated aluminum specimen. The specimen was cured under the condition of M.P.T. to prepare a specimen having a thickness of 70 ± 10 μm. The color of the paint was chosen white to compare the stain resistance more accurately.

In the case of the curing agent used, X.L-552 or C.550 and B.F-1540 or B-1530 were used in an equivalent ratio in the resin having two different functional groups at the end, and a resin having only a carboxyl group at the end. For example, triglycidyl isocyanurate or X.L-552, C.P-550 and the like were used as equivalent ratios. However, the curing agent used in the examples does not limit the scope of the present invention. Coating formulations, coating properties, and weatherability of the application prepared in the above are as shown in Tables 1 to 3.

TABLE 1

Paint formulation (unit: g)

TABLE 1a

*One. EMS hardener (1 equivalent = 90) * 2. Hulse's hardener (1 equivalent = 280)

* 3. Shivagai Company (Tinubin 900: UV absorber, Tinubin 144: Hals, I.R.G1076: Antioxidant)

*4. Wally's curing agent (1 equivalent = 550)

* 5. U.C.B manufactured acrylic curing agent (1 equivalent = 700)

* 6. Hardening accelerator of Japanese wild skewers

TABLE 2

Paint Application Results

a: Mitsubishi Uni Pencil Test

b: Chromate-treated aluminum fragments (1 mm interval)

c: CR steel, zinc phosphate coating / Ericsen tester

d: CR steel, zinc phosphate coating / 3/16 "bar

e: CR steel, zinc phosphate coating / Dupont type

f: Comparative test with solvent fluorine (80 ℃ × 1 hour / wash)

g: Chromate treated aluminum specimen spot test (5% NaOH / 72 hours)

h: Chromated aluminum specimen spot test (10% H2SO4 / 240 hours)

i: Chromate treated aluminum specimen spot test (xylene / 24 hours)

j: Chromate treated aluminum specimen / ASTM B117 (1000 hours)

TABLE 2a

Paint Application Results

TABLE 2b

Paint Application Results

* Curing condition: 200 ℃ × 10 minutes (based on M.P.T)

* Pollution resistance: ① Test method: Mix the carbon in water (NV = 10%), apply it on the specimen, dry it in the oven at 80 ℃ for 1 hour, and wash it with water and isopropyl alcohol.

② Criteria (solvent fluoride: 10 points)

Very good ← Very poor

10 points ......................... 1 point

* Leveling: ◎ → Very good, ○ → Good, ○-△ → Somewhat insufficient, △ → Poor, × → Poor

TABLE 3

 Weathering Result (60 ° Gloss / Gloss% of Q.U.V Time)

In the case of the paint using the conventional weather-resistant resin, the weather resistance and contamination is low, the use is limited to farm equipment, steel furniture, fence, etc. However, the paint using the resin according to the present invention is very excellent in weather resistance and stain resistance as can be seen from Tables 1 to 3 can be applied to the aluminum window frame or outdoor panel that mainly used a solvent-type paint in addition to the above applications.

Claims (3)

(1) 49 to 68 parts by weight of one or more divalent or more aromatic carboxylic acids, and 4 parts by weight or less of one or more divalent or more alicyclic or aliphatic acids having 6 or less carbon atoms in the main chain, and short side chain length and carbon number in the main chain. 30 to 38 parts by weight of one or more divalent glycols having two or more valences, and 2 to 8 parts by weight of trimethylol propane, 1.0 part by weight or less of 1.0 or more parts of a tin catalyst as 1.0 to 1.3 in the equivalent ratio of alcohol / acid, 240 Reaction at ˜250 ° C. to prepare a prepolymer having a hydroxyl value of 30 to 80 and a melt viscosity of 12 to 50 poise (175 ° C. I. V. eye viscometer), and then (2) 1 to 15 parts by weight of isophthalic acid, 1 to 10 parts by weight of hexahydrophthalic anhydride, and 0.1 or more parts of tin catalyst are added to 100 parts by weight of the prepolymer resin, and reacted at 210 to 220 ° C. and, The divalent or more aromatic carboxylic acid is selected from the group consisting of terephthalic acid, isophthalic acid, dimethyl isophthalic acid, phthalic anhydride, and tert-butyl isophthalic acid, The divalent or higher alicyclic or aliphatic acid having 6 or less carbon atoms in the main chain is 1 from the group consisting of succinic acid, adipic acid, azelaic acid, hexahydro phthalic anhydride, methyl-nucleated hydrophthalic anhydride, and 1,4-cyclohexane dicarboxylic acid. More than one species are selected, The hydroxyl value is 5 to 40, the acid value is 10 to 50, the melt viscosity is 15 to 50 poise (200 ° C., I. C. eye viscometer), the average number of functional groups at the resin terminal is 1.5 to 3, and hydroxyl at the terminal. A polyester resin for powder coating, having excellent weather resistance and fouling resistance, having a practical group and a carboxyl group. The divalent glycol of claim 1, wherein the side chain is short and has two or more carbon atoms in the main chain is neopentyl glycol, ethylene glycol, propylene glycol, 2-butyl-2ethyl-1,3 propane diol, 1,3- Butylene glycol, hydrogenated bis phenol-A, 1,6-hexane diol, 1,4-cyclohexane dimethylol, 3-hydroxy-2,2-dimethyl propyl 3-hydroxy-2,2, -dimethyl propano Eight, and a polyester resin for powder coating excellent in weather resistance and fouling resistance, characterized in that at least one selected from the group consisting of diethylene glycol. 29 to 68 parts by weight of the polyester resin for powder coating according to claim 1, 1 to 23 parts by weight of a curing agent having a hydroxyl or epoxy group equivalent of 70 to 600, and 1 to 10 parts by weight of a urethane curing agent having a -NCO equivalent of 250 to 300. Parts, 30 to 33 parts by weight of titanium dioxide, 15 parts by weight or less of extender pigments, and 7 parts by weight or less of other additives, The other additive is a powder coating composition, characterized in that the curing accelerator, ultraviolet absorber, Hals, antioxidant, flow improver, and pinhole inhibitor.