KR970000210B1 - Water dispersed resin - Google Patents

Abstract

The resin is composed of water dispersed polyester resin with acid value 10-90 mgKOH/g, oxalic acid value 70-150 mgKOH/g, weight-average molecular weight 3,000-30,000 and the content of aromatic compound 40-70 wt%, water dispersed polyuretane polyol resin with acid value 5-15 mgKOH/g, oxalic acid value 40-90 mgKOH/g and weight-average molecular weight 1,000-40,000, amino resin as a curing agent and water dispersed block polyisocyanate resin.

Description

Water dispersion resin

The present invention relates to a water-soluble coating composition characterized in that it is prepared using a water-dispersible resin and the main binder.

More specifically, the acid value of 10 to 90 mgKOH / g, the hydroxyl value of 70 to 150 mgKOH / g, the weight average molecular weight of 3,000 to 30,000, and the 40 to 70 to improve the chemical resistance of the water-soluble paint and to improve the mechanical properties, in particular the chipping properties. A water-dispersed polyester resin containing a weight percent aromatic compound, an acid value of 5 to 15 mgKOH / g, and a water-dispersed polyurethane polyol resin containing a weight average molecular weight of 10,000 to 40,000 with a hydroxyl value of 40 to 90 mgKOH / g are 1: 1 to 1. It is composed of a weight ratio of 6: 1, and the curing agent is used in combination with an amino resin and a water-dispersed block polyisocyanate resin, the ratio of the water-dispersed polyester resin and the amino resin is 90:10 to 80:20 in the solid content ratio, The ratio of the polyurethane polyol resin and the water-dispersed blocked polyisocyanate resin is 70:30 to 60:40 in the solid content ratio and the combination ratio of the two classes is 80:20 to 70:30 in the solid content ratio. It relates to a water-soluble coating composition comprising a binder portion and an additive, a pigment and a sieving pigment.

In recent years, due to serious environmental protection and environmental problems, the paint industry has been a lot of research on the aqueous and powdering in the paint industry. However, various types of conventional water-soluble resins for paints are used depending on the purpose of use, such as water-soluble acrylics by solution polymerization, water-soluble alkyd resins, and emulsion resins by emulsion polymerization. However, these water-soluble resins have water resistance, rust resistance, and acid resistance. In terms of physical properties such as chemical resistance, chipping resistance, impact resistance, and bendability, the physical properties are notably inferior to those of the currently available useful paints, and in terms of workability, spray coating conditions, storage properties of paints, and appearance of coatings. Could not satisfy their desire.

That is, the conventional water-soluble resins and paints have the following problems when applying paints due to the properties of the water-soluble resin itself and the special properties of water. In the case of solution type water-soluble resins and paints, the evaporation rate of water is remarkably slow, which greatly changes the paintability depending on the weather of the paint shop or external conditions of the paint equipment, and in the case of wet on wet, organic solvents. Popping occurs due to the difference of evaporation rate between water and moisture. Therefore, it is difficult to adjust the temperature and humidity conditions of the spray workplace to the optimal state.

In addition, in order to enable the resin solubility, a problem has arisen because a large amount of hydroxyl groups and carboxyl groups must be modified in the polymer back-bone. That is, it is easy to generate bubbles when applying paint, and the resistance to foreign substances such as cratering is weakened, and since the resin itself contains a large amount of acid groups, there are many problems in chemical resistance such as acid resistance, water resistance, alkali resistance, and the like.

Therefore, the object of the present invention was to suppress the carboxylic acid of the polymer chain as much as possible to solve the above-mentioned problems, and to improve the chemical resistance, acid resistance, alkali resistance, water resistance, chipping resistance and the like in the coating composition and ease of operation The present invention provides a resin composition and a water-soluble coating composition containing the same, which can prevent popping and cratering, which may occur due to the slow evaporation rate of water.

In order to achieve the above object, in the present invention, the acid value of 10 to 90 mgKOH / g, the hydroxyl value of 70 to 150 mgKOH / g, and the weight of 3,000 to 30,000 in order to improve the chemical resistance of the water-soluble paint and improve the mechanical properties, in particular, the chipping property. A water-dispersed polyurethane polyol containing an average molecular weight, a water-dispersed polyester resin containing an aromatic compound of 40 to 70% by weight, an acid value of 5 to 15 mgKOH / g, and a weight average molecular weight of 10,000 to 40,000 a hydroxyl value of 40 to 90 mgKOH / g. The resin is composed of a weight ratio of 1: 1 to 6: 1, and as the curing agent, an amino resin and a water-dispersed block polyisocyanate resin are used together. In the present invention, the ratio of the water-dispersed polyester resin and the amino resin is represented by a solid content ratio. The ratio of the water-dispersed polyurethane polyol resin and the water-dispersed blocked polyisocyanate resin is 90:10 to 80:20, and the solid content ratio is 70:30 to 60:40. A water-soluble coating composition was prepared, comprising a binder portion having a solid content ratio of 80:20 to 70:30, a thickener, a dispersant, a smoothing agent, a cosolvent, a pigment, and a sieving pigment.

The present invention will be described in more detail as follows.

First, the polyester resin is designed in a molecular structure capable of simultaneously containing an acid group and a hydroxyl group in the resin. In the above, the acid group is a functional group that can facilitate neutralization and solubilization, and the hydroxyl group is a functional group that can cause a curing reaction with the amino resin when the coating is applied.

Referring to the polyester polymerization step, the first is a general polyester polymerization step.

R ₁ : aliphatic, aromatic compound

R ₂ : aliphatic or aromatic compound (including at least one polyvalent or higher polyvalent acid)

n: 5 or more

As shown in the above formula, a polyester is synthesized using a polyhydric alcohol and a polyvalent acid. As a polyhydric alcohol used above, alcohols, such as dihydric and trivalent, are used, but dihydric alcohol is preferable. However, a small amount of trihydric alcohol may be used depending on the state of the physical properties.

The dihydric alcohols include neopentyl glycol, 1,4-butanediol, 1,6-hexanediol, ethylene glycol, diethylene glycol, cyclohexanediol, and the like. The trivalent alcohols include trimetholol propane and trimetholol. Ethane and the like, which are used alone or in combination of two or more.

As the polyvalent acid, divalent and trivalent acids are used, and the acid used in the present invention includes trimellitic anhydride, terephthalic anhydride, fumaric acid, maleic acid, adipic acid, sebacic acid, and cyclohexane dicarboxyl. Acids, isophthalic acid, phthalic acid, etc. are used, and a tin-type catalyst is used as a catalyst.

After making it react at the temperature between 160-200 degreeC using the said raw material, reaction is complete | finished when acid value reaches about 10-90 mgKOH / g, More preferably, it is 20-80 mgKOH / g. If it is 10 mgKOH / g or less in the range of the acid value of the reactant, it is very difficult to be solubilized, and if it is 90 mgKOH / g or more, the chemical resistance such as water resistance, alkali resistance, acid resistance and the like is significantly reduced. In addition, the aromatic compound should account for 40 to 70% by weight based on the total resin.

If it is 40 wt% or less, acid resistance and alkali resistance are very poor, and if it is 70 wt% or more, weather resistance and ultraviolet resistance are very poor.

In addition, the resin has a hydroxyl group having a hydroxyl value of about 70 to 150 mgKOH / g, preferably containing a hydroxyl group of 80 to 120 mgKOH / g, but having a hydroxyl value of 70 mgKOH / g or less, to the water-soluble intermediate (primer surfacer) for automobiles When applied, the hardness is very high, chipping property and bendability is lowered, in the case of 150mgKOH / g or more, the coating film is too soft and mechanical strength is lowered. Therefore, out of the range of the hydroxyl value has a great effect on the overall coating composition. In addition, the combination of the polyurethane resin containing a hydroxyl group and the polyester resin may cause a decrease in gloss due to the difference in curing rate, the curing time of the polyester alone at this time is 150 ℃, gelation of 5 to 20 minutes Take a gelation time. If the gelation time is 5 minutes or less, the curing time is too short, so that a coating film is formed before water is evaporated, thereby causing a popping phenomenon or a immersion phenomenon. This results in poor mechanical properties due to incomplete hardening.

The number average molecular weight of the resultant water-dispersed polyester resin of the present invention is about 1,000 to 10,000, and the weight average molecular weight has about 3,000 to 30,000.

The second stage is the neutralization and solubilization stage. Using the polyester and the neutralizing agent prepared above to form a salt to be easily dispersed in water (dispersion). As said neutralizing agent, amines are used, and as amines, primary, secondary and tertiary amines are used. Preferably, tertiary amine is used, but diethanol amine, diethyl ethanol amine, phenyl diethanol amine, methyl diethanol amine, dimethyl amino ethanol, or the like is used alone or in combination of two kinds. Account for weight percent. In addition, a diol-based crude solvent is used to suppress the increase in viscosity and to give a smooth manufacturing process. It is liquid at room temperature, and 1,4-butylene glycol, ethylene glycol, diethylene glycol, or the like is mixed alone or two or more. It is used in the amount of 10 to 20% by weight of the total resin. In this reaction process, the co-solvent is mixed with the polyester resin in the range of 130 to 150 ° C, and 10 to 30% by weight of water and 5 to 10% by weight of a neutralizing agent are mixed in the reactor at a temperature of 100 ° C or less.

If the content of the neutralizing agent is less than 5% by weight, it is difficult to accept water due to incomplete salt formation, and at 10% by weight or more, the problem of cracking and popping of the coating film occurs due to a large amount of remaining neutralizing agent. . In addition, when the content of the solvent is less than 10% by weight, there is a disadvantage in that the operation is not easy due to the high viscosity, at 20% by weight or more there is a disadvantage that can not form a beautiful appearance due to the remaining solvent when applying the paint.

The final water-based polyester resin obtained by the above manufacturing process has a solid content of 50 to 80%, an acid group of 20 to 50 mgKOH / g, and contains a hydroxyl value of 70 to 150 mgKOH / g.

Next, the water-dispersed polyurethane polyol resin of the present invention was designed a molecular structure so that the acid and hydroxyl groups can be simultaneously included in the resin. Here, the acid group is a functional group that can be neutralized and solvated, and the hydroxyl group exists as a functional group capable of causing a curing reaction with the water-dispersed block polyisocyanate resin when the paint is applied.

Formation reaction of the water-dispersed polyurethane polyol resin can be divided into three stages of reaction, one step is a polyester polyol synthesis step. This reaction synthesizes polyester polyols using polyhydric alcohols and polyvalent acids, as is generally known. As the polyhydric alcohol used in this step, dihydric and trihydric alcohols are used, but dihydric alcohol is preferably used to avoid gelation of the final product. The dihydric alcohols include 1,6-hexanediol, 1,4-butanediol, 1,2-propylene glycol, 1,3-propylene glycol, neopentyl glycol, ethylene glycol, diethylene glycol, and cyclohexanediol. These are used individually and in mixture of 2 or more.

As the polyvalent acid of the same step, divalent and trivalent acids are used. Acids used in the present invention include phthalic anhydride, isophthalic acid, terephthalic acid, adipic acid, maleic acid, fumaric acid, sebacic acid, and cyclohexyl polycarboxylic acid. And the like, which are used alone or in combination of two or more thereof, and a tin-based catalyst is used.

This reaction is made to react at the temperature between 180-220 degreeC using the said raw material, and when an acid value reaches zero, reaction is complete | finished. The present polyester polyol has a hydroxyl group having a hydroxyl value of about 50 to 200 mgKOH / g, and preferably contains a hydroxyl group of 100 to 120 mgKOH / g, but having a hydroxyl value of 50 mgKOH / g or less increases the molecular weight and viscosity of the polyester polyol. It is difficult to fully react with polyhydric isocyanate, which is the next step, and it is difficult to form polyurethane polyol prepolymer, and when it has a hydroxyl value of 200 mgKOH / g or more, the molecular weight of the polyester polyol is reduced, and the hard-segment is reacted with the next stage of polyvalent isocyanate. A sharp increase in can lead to gelation.

Therefore, although the molecular weight of the polyester polyol of this invention uses the thing of 500-3000, Preferably it is 800-1500.

The second step is to form the polyurethane polyol prepolymer. In this step, first of all, the polyester polyol prepared in one step is mixed with a saltable group which is an important reaction component in ensuring the dispersibility of the water-dispersible polyurethane polyol resin. The role of this salting group is to neutralize with the corresponding amount of neutralizing agent after the polyurethane polyol prepolymer is formed. The amount of the salting group accounts for 4 to 7% by weight of the polyurethane polyol prepolymer, Examples include dimethylol propionic acid.

The two components are thoroughly mixed at 90 to 100 ° C., and when complete mixing is performed, the temperature is lowered to about 70 ° C. and polyvalent isocyanate is added over 1 hour.

Polyvalent isocyanates which react with the two components to form a polyurethane polyol prepolymer include tetramethylene diisocyanate, hexamethylene diisocyanate, dodecylmethylene diisocyanate, cyclohexane-1,3-diisocyanate, cyclohexane-1,4 -Diisocyanate, 1-isocyanate-3-isocyanatemethyl-3,5,5-trimethyl cyclohexane, 4,4-diisocyanate cyclohexylmethane, 2,4-diisocyanate toluene, 2,6-isocyanate toluene, 4, 4-isocyanate naphthalene, 1, 3-bis (isocyanate methyl) cyclohexane, 1, 4 (isocyanate methyl) cyclohexane, etc., The molecular weight is preferably 200 to 500.

This reaction is completely charged with polyhydric isocyanate, and then maintained for 70 hours to 100 hours.

The end point is then taken at the point where the isocyanate content is zero. The polyurethane polyol prepolymer formed in the reaction includes an acid group and a hydroxyl group at the same time. The acid group of the polyurethane polyol prepolymer has 20 to 70 mgKOH / g, and a preferable acid group is 30 to 50 mgKOH / g. When the acid value is 20 mgKOH / g or less, it is difficult to neutralize and solubilize the polyurethane polyol prepolymer because of low salting in the next step, and when the acid value is 70 mgKOH / g or more, the water-dispersed polyurethane of the present invention When the polyol resin is applied to the paint, physical properties such as water resistance, acid resistance and alkali resistance of the coating film are lowered. Moreover, the hydroxyl group of the said polyurethane polyol prepolymer has about 40-90 mgKOH / g, and a preferable hydroxyl value is 60-80 mgKOH / g.

In the above range, the hydroxyl value of 40 mgKOH / g or less causes a problem of hardening and gloss of the coating film when the coating is applied, and a problem of deteriorating mechanical properties due to the soft nitriding of the coating film above 90 mgKOH / g.

In a typical water-dispersed polyurethane resin formation reaction, the prepolymer stage leaves the isocyanate at the sock end for solubilization and forms urea rings at both ends with a chain extender (eg hydrazine). However, the water-dispersed polyurethane resin thus obtained softens the coating film after curing due to the lack of functional groups that can cause a curing reaction when the coating is applied, thus adversely affecting the coating properties and chipping properties. Inadequate

Therefore, in order to solve this disadvantage, the present invention has a hydroxyl value of 40-90 mgKOH / g of the polyurethane polyol prepolymer by adjusting the equivalent ratio of OH / NCO to 1.1-1.8 in synthesizing the polyurethane polyol prepolymer. This remaining hydroxyl value acted as a functional group to cause a curing reaction with the water-dispersed blocked polyisocyanate when the coating was applied, which could greatly improve the hardness and chipping properties of the coating film.

The final stage of the water-dispersed polyurethane polyol resin formation reaction of the present invention is the neutralization and solubilization stage. Since the carboxylic acid group which is the salted group which remains unreacted exists in the chain | strand of the polyurethane polyol prepolymer made above, a salt is formed using an appropriate neutralizing agent, and the dispersibility of this resin is improved.

Suitable neutralizing agents used here include amines, and preferred are tertiary amines such as diethanolamine, diethylethanolamine, dimethylethanolamine, triethylamine, tributylamine, phenyldiethanolamine and methyldiethanolamine. Etc. are used individually or in mixture of 2 or more types. The amount of neutralizing agent used is about 1 to 5 weight% with respect to this water-dispersed polyurethane polyol resin, and neutralization degree is about 50 to 70% of range. If the degree of neutralization is less than 50%, the problem of water solubility becomes difficult due to the formation of an incomplete salt, and if the degree of neutralization is 70% or more, the particle size of the resin may be unnecessarily lowered. This caused problems such as cratering and popping phenomenon in the coating film during coating application.

In order to suppress the increase in the viscosity of the resin during the neutralization reaction and to give a smooth manufacturing process, about 6 to 10% by weight of the co-solvent is added. Representative co-solvents include methyl ethyl ketone, acetone, dimethyl formamide, Glycol ether esters, florinated hydrocarbons, an-methyl-2-pyrrolidone, and hydrogenated furan. In the reaction process, a mixture of 1 to 5% by weight of a neutralizer and 6 to 10% by weight of a co-solvent is added to the polyurethane polyol prepolymer maintained at a temperature of 70 ° C. or less over 15 to 20 minutes.

Thus, when the neutralization reaction is completed, the solubilization starts. At the initial point of the introduction of water, the viscosity increase occurs because most of the materials in the reactor are organic phase materials. If water is added continuously and the phase transition occurs, the viscosity decreases to form a stable aqueous dispersion.

The number average molecular weight of the final water-dispersed polyurethane polyol resin formed as described above is 3,000 to 12,000, has a weight average molecular weight of about 10,000 to 40,000, the final acid value reaches 5 to 15 mgKOH / g and the hydroxyl value is 40 to 90 mgKOH / reaches g. In addition, the water-dispersed polyurethane polyol resin of the present invention forms a stable water dispersion of 40 to 60% solids, pH of 6.5 to 7, particle size of 80 to 150 nanometers, surface tension of 35 dyne / cm.

When the water-dispersed polyester resin prepared by the method of the present invention and the water-dispersed polyurethane polyol resin are applied to a water-soluble medium or undercoat (primer surfacer) for automobiles, the water-disperse resins are used as main binders on the electrodeposited coatings. Spray the water-soluble paint prepared by using a dry coating film to 30 to 45 microns and maintain a setting time for about 10 minutes, and then flash off for 10 minutes at 20 to 25 ° C and 10 minutes at 25 to 85 ° C. flash off) and heat cured at 150 ° C to 180 ° C for 20 minutes.

It is preferable to mix the water-dispersed polyester resin and the water-dispersed polyurethane polyol resin in the weight ratio of 1: 1-6: 1 in the coating composition which uses the water-dispersible resin of this invention as a binder. When the ratio of the water-dispersible resin is 1: 1 or less, the mechanical resistance of the acid resistance, alkali resistance and the coating film is very low, and when the ratio is 6: 1 or more, the chipping resistance is very poor, and the weather resistance and ultraviolet resistance are remarkably inferior.

As the curing agent that causes the curing reaction with the water-disperse polyester resin, an amino resin is used. Examples of the typical amino resin include cymel 303, cymel 305, cymel 327, cymel 1116, and cymel 1123 (cyanamai). Desa), Mapleal Mf 904, 900, 920 (Cheist), Resmen 714, 717, 730 (Monsanto), etc.The curing agent is 10 to 20% by weight as a solid with respect to the water-dispersed polyester resin. use. At this time, if the curing agent is 10% by weight or less, the degree of crosslinking is decreased, so that the coating film is very soft, and adhesiveness and chemical resistance are deteriorated. This can lead to a sharp increase in viscosity, especially during paint storage.

The curing agent is characterized by a very small amount of premethyrol (-CH ₂ OH), and most of the alkylate (-CH ₃ OR) is a melamine resin that emits a small amount of formaldehyde (HCHO), bubbling This tends to be less. In addition, it exhibits a small weight loss during curing and has the advantage of causing a fast curing reaction even at low temperatures when using a weak acid catalyst.

This is because a certain acid is included in the resin when it is solvated. This is an important factor used as a curing agent for water soluble intermediates (primer surfacers).

The curing agent consists of three mixtures:

Most of them consist of (1) and (2), and (3) is added in small amounts. As this hardening | curing agent, it is preferable to use that whose weight ratio of (3) is 10% or less of the weight of all the hardening | curing agents. If it exceeds 10%, it will break the stability of paint when dispersing.

In addition, as the curing agent to cause a curing reaction with the water-dispersed polyurethane polyol resin is to use a water-dispersible block polyisocyanate resin.

There are various methods for producing the water-dispersible curing agent, but in the present invention, a method of blocking with alcohols is adopted. That is, a method in which the alcohol which was blocked with the increase of the temperature during coating application volatilized and the remaining NCO content caused the hydroxyl group and the curing reaction of the water-dispersible polyurethane polyol resin was adopted. The preparation of the water-dispersible blocked polyisocyanate resin acting as a curing agent of the present invention will then be described briefly.

Α, α-dimethylol propionic acid, containing both polyhydric aliphatic isocyanates (mentioned in the preparation of the waterborne polyurethane polyol resins above) and polyhydric alcohols and saltable groups necessary to ensure water dispersibility of the copper resin. React at 90 to 100 ° C. In this reaction, about 2 to 5% by weight of cosolvent is added to suppress the viscosity increase of the resin and to give a smooth manufacturing process. As typical cosolvents, methyl ethyl ketone, acetone, dimethylformamide, and glycol Esters, an-methyl-2-pyrrolidone, and the like, which are used alone or in combination of two or more.

The end point of the reaction terminates the reaction when the residual NCO content is about 3 to 6% and blocks the remaining NCO with alcohol. Alcohols used in this step include isopropanol, n-propanol, n-butanol, n-pentanol, 2-ethyl hexanol, 2-ethoxyethanol, cyclohexane, and the like. . After blocking the reaction with alcohol, slowly adding a mixture of neutralizing agent and water gives a yellow, stable aqueous block polyisocyanate resin.

The amount of neutralizing agent used in this reaction is 4 to 6% by weight based on the total resin. The final aqueous block polyisocyanate resin formed as described above has a yellow viscous solution with a solid content of 35 to 50%, a pH of 7 to 9, and a viscosity of 30 pas.

Therefore, the curing agent is used 30 to 40% by weight as a solid content during the curing reaction with the water-dispersed polyurethane polyol resin, wherein if the curing agent is 30% by weight or less, the crosslinking degree is lowered, the adhesion and chemical resistance worsens due to softening of the coating film If it is more than 40% by weight, unnecessary hardening of the coating film may lead to a decrease in mechanical strength and gloss, and may cause a sharp increase in viscosity during paint storage.

In order to facilitate water solubility and provide a more beautiful appearance to the water-soluble coating composition, particles having a particle size of 5 micrometers or less are used to add colored pigments and spherical extender pigments. This is because the water-soluble coating composition uses water as a solvent, so the evaporation rate is very slow, so that the total surface area must be widened to speed up the evaporation rate of water. If 5 or more colored pigments and needle-like sieving pigments are used, it is difficult to accurately disperse the paint during dispersion (red developed for 2 hours in the manufacture of the paint), and the evaporation rate of water slows down when the coating film is applied. And a cratering phenomenon occurs, a problem that the coating film is rough.

Pigments used in the water-soluble coating composition of the present invention include colored pigments such as titanium oxide and carbon black, and extender pigments such as barium sulfate and magnesium silicate. 15 to 25% by weight of the water-soluble coating composition of the present invention is used. If the pigment used is less than 15% by weight, the concealment force is reduced and the coating film is hardened. If the pigment is more than 25% by weight, the adhesion between the layers and the gloss are reduced, the mechanical properties are lowered and the price is increased. In addition, the ratio of the extender pigment of the present invention is characterized in that the weight ratio of barium sulphate and magnesium silicate is 1/1, which is a composition ratio that facilitates water solubility and gives the best appearance.

In addition, an additive is used to sufficiently exhibit the function of the water-soluble coating composition of the present invention. In the present invention, the following three additives are used.

First, a thickener is used to prevent the flow of the coating composition of the present invention, to facilitate water solubility, and to smooth the coating. As the thickener, fused silica and an associative thickener are 1: 1 to 1: 3: 1. It is characterized in that the weight ratio of 1.0 to 3.0% by weight based on the total water-soluble coating composition is added to the soluble silica Aerosio (Rerosio) R972 (Degussa) is added to the mill-base and Bermodol PUR2100 an associative thickener (Langer Co., Ltd.) is made into a 5 to 10% aqueous solution and then added after mill-base.

Secondly, a dispersant is introduced into the mill-base in order to efficiently disperse the pigment in the coating composition of the present invention in a uniformly stable state in the binder. In the present invention, Sufinol 104E (Air products) is used, but the amount is 0.4 to 1.0% by weight of the total water-soluble coating composition.

In addition, the water-soluble coating composition of the present invention is made into a 10-15% aqueous solution made of silicon-free leveler in order to smooth the leveling property and improve the wetting with the resin when the coating film is formed in the present invention. Editor XW 395 (Hoechst) is used. In this case, the usage-amount shall be 0.4-1 weight% of all the water-soluble coating compositions.

In addition, butylglycol is added as a co-solvent in the water-soluble coating composition of the present invention, the role of the co-solvent greatly improves the smoothness of the coating film, lowers the minimum coating film formation temperature, greatly contributes to the volatilization of the solvent during the painting operation.

In addition, since it is very well mixed with water, water-dispersible resin and water-soluble resin at room temperature, it contributes greatly to the viscosity reduction of the paint. The usage-amount of butyl glycol in this invention is used in 3.0 to 5.0 weight% of all the coating compositions.

The following examples and comparative examples more specifically describe the efficacy and effect of the coating composition of the present invention, but do not limit the scope of the present invention. Production Examples 1 to 4 below are methods for producing a water-dispersed polyester resin, Production Examples 5 to 7 are methods for producing a water-dispersed polyurethane polyol resin, and Production Example 8 relates to a method for producing an aqueous blocked polyisocyanate resin.

Preparation Example 1

20.0 parts by weight of phthalic anhydride, 20.1 parts by weight of adipic acid, 16.0 parts by weight of trimellitic anhydride, 34.5 parts by weight of 1,4-butylene glycol, diethylene glycol 9.4 in a reactor equipped with a stirrer, a thermometer, a nitrogen injection pipe, a separator, and a cooler 0.1 part by weight of a passlet is inserted as parts by weight and catalyst. The temperature was gradually increased while stirring at a rate of 750 rpm under nitrogen injection, and the temperature was maintained at 180 ° C. When the acid value reached 60 mgKOH / g while the reaction was carried out, the reaction mixture was cooled to 140 ° C., and the nitrogen was excessively supplied by 75 mm Hg. At this time, the acid value is adjusted to 50mgKOH / g. Stop excess nitrogen, cool again, and reach 120 ° C to insert 18 parts by weight of 1,4-butylene glycol. Agitation is made stronger than the above speed to lower the viscosity. Reduce the stirring speed and lower the temperature below 100 ℃. Thereafter, 16.4 parts by weight of distilled water and 7.4 parts by weight of dimethylethanolamine were mixed well in an injector in a neutralization and solubilization step, then injected into the reactor over 20 minutes, stirred at 65 ° C. for 30 minutes, and the reaction was terminated. An ester resin was prepared. The resulting water-dispersed polyester resin has an acid value of 20-25 mgKOH / g, a viscosity of Brookfield viscometer at 25 ° C., 2.5 rpm, 8000 cps, a hydroxyl value of 80-110 mgKOH / g, a molecular weight of 15,000, and a pH of 8.7.

Preparation Example 2

37.7 parts by weight of phthalic anhydride, 14.9 parts by weight of trimellitic anhydride, 45.1 parts by weight of 1,4-butylene glycol, 19.8 parts by weight of 1,6-hexanediol, 12.5 parts by weight of diethylene glycol, and 0.1 parts by weight of a bucket in the reactor It was prepared in the same manner as in Preparation Example 1 above. The acid value of the water-disperse polyester resin is 20-25mgKOH / g, the viscosity is 21,000cps at 25 ℃, 2.5rpm by Brookfield viscometer, the hydroxyl value is 80 ~ 110mgKOH / g, molecular weight is 13,000, pH is 8.8.

Preparation Example 3

37.0 parts by weight of adipic acid, 14.3 parts by weight of mustrimeric acid, 12.7 parts by weight of 1,4-butylene glycol, 30.3 parts by weight of 1,6-hexanediol, 6.7 parts by weight of diethylene glycol, and 0.1 parts by weight of a bucket in the reactor. It was prepared in the same manner as in Preparation Example 1 above. The acid value of the water-disperse polyester resin is 20 ~ 25mgKOH / g, the viscosity is Brookfield viscometer at 25 ℃, 25rpm, 1,000cps, the hydroxyl value is 80 ~ 110mgKOH / g, molecular weight is 11,000, pH is 7.7.

Preparation Example 4

22.1 parts by weight of phthalic anhydride, 32.2 parts by weight of trimellitic anhydride, 6.7 parts by weight of 1,4-butylene glycol, and 27.6 parts by weight of 1,6-hexanediol, and then added to the reactor, the acid value was maintained after raising the temperature to 180 ℃ The temperature was cooled to 140 ° C. when reached 110 mgKOH / g. Thereafter, when the acid value reached 105 mgKOH / g, nitrogen was excessively injected, and when the acid value reached 85 mgKOH / g, the excess nitrogen was stopped to lower the temperature to 120 ° C. 19 parts by weight of 1,4-butylene glycol was injected at 120 ° C, and the preparation method was prepared in the same manner as in Preparation Example 1. The acid value of the water-disperse polyester resin is 60mgKOH / g, the viscosity is a Brookfield viscometer at 25 ℃, 2.5rpm 8,000cps, the hydroxyl value is 80 ~ 110mgKOH / g, molecular weight is 13,000, pH is 6.0.

Preparation Example 5

332, 26 parts by weight of isophthalic acid, 280.14 parts by weight of adipic acid, 209.75 parts by weight of 1,6 hexanediol, 243.52 parts by weight of propylene glycol and a catalyst as a catalyst in a reactor equipped with a stirrer, a thermometer, a nitrogen injection tube, a separator and a cooler 1.1 Insert the parts by weight. The temperature was gradually increased while stirring at a speed of 300 rpm under nitrogen injection, and the temperature was maintained at 200 ° C. When the acid value reaches 7mgKOH / g during the reaction, the speed of the stirrer is increased to 500rpm, the reaction is continued for 15 minutes while the nitrogen is supplied with an excess of 75mmHg, and the reaction is terminated when the acid value falls below 3mgKOH / g. The polyester polyol produced by this reaction has a hydroxyl value of 110 mgKOH / g and has a molecular weight of 950. 281.0 parts by weight of the polyester polyol thus prepared was introduced into a newly installed reactor, 26.8 parts by weight of dimethylol propionic acid, 59.2 parts by weight of N-methyl-2-pyrrolidone, and 0.6 parts by weight of dibutyltin dilaurate were introduced into the reactor. Insert under injection and raise the temperature to 100 ° C. so that the ingredients are thoroughly mixed. Once the ingredients are thoroughly mixed the temperature is cooled to 70 ° C. and 62.2 parts by weight of isophorone diisocyanate are injected over 1 hour. Thereafter, the mixture is reacted for 3 hours or more while maintaining at 80 ° C. Upon completion of the reaction, a prepolymer having a hydroxyl value of 73 mgKOH / g and an acid value of 30.3 mgKOH / g was prepared. The prepolymer is maintained at 70 ° C. to prepare an aqueous dispersion, and 11.3 parts by weight of dimethylethanolamine is injected into the prepolymer over 15 minutes and stirred at a speed of 500 rpm. Then 408.2 parts by weight of distilled water maintaining 40 ℃ was slowly added and stirred for 1 hour until a complete aqueous dispersion is formed. The water-dispersed polyurethane polyol resin of the present invention obtained by the above method became a stable water dispersion having an average particle of 100 to 120 nanometers.

Solid content of the water-dispersed polyurethane polyol resin is 45%, acid value 11.1mgKOH / g, hydroxyl value 73mgKOH / g, pH 6.54, the viscosity is a white water dispersion resin of Gardner C in a bubble viscometer.

Preparation Example 6

271.4 parts by weight of polyester polyol prepared in Preparation Example 5, 24.12 parts by weight of dimethylol propionic acid, 53.8 parts by weight of en-methyl-2-pyrrolidone, and 0.4 parts by weight of dibutyltin dilaurate were introduced into the reactor. It stirred in the same manner as in Example 5. After the reaction mixture was completely stirred, the mixture was cooled to 70 ° C. and 59.94 parts by weight of isophorone diisocyanate was added. The reaction process was the same as in Preparation Example 5. Upon completion of this reaction, a prepolymer having a hydroxyl value of 77.2 mgKOH / g and an acid value of 28.4 mgKOH / g is formed. In order to make the prepolymer into an aqueous dispersion, 10.3 parts by weight of dimethyl ethanolamine was injected into the prepolymer over 15 minutes, dispersed at a speed of 500 rpm, and then 370.8 parts by weight of distilled water maintained at 35 ° C was gradually formed to form a complete aqueous dispersion. Stirred at a speed of 500 rpm. The water-disperse polyester polyol resin of this invention obtained by the said method became the stable water dispersion which is an average particle 90-110 nanometers. The water-dispersed polyurethane polyol resin is 46% solids, acid value 10.2mgKOH / g, hydroxyl value 77.2mgKOH / g, pH 6.35, the viscosity is a white water dispersion resin Gardner B in a bubble viscometer.

Preparation Example 7

500.0 parts by weight of polyester polyol prepared in Preparation Example 5, 232.4 parts by weight of polycaprolactone diol, 70.0 parts by weight of dimethylol propionic acid, and 1 part by weight of dibutyltin dilaurate were introduced into a reactor and stirred in the same manner as in Preparation Example 5. It was. After the reaction mixture was completely stirred, the mixture was cooled to 70 ° C, 350.0 parts by weight of isophorone diisocyanate was added, and the reaction process was the same as in Preparation Example 5.

At the end of the reaction, the prepolymer had a residual isocyanate content of 2.47% and an acid value of 62 mgKOH / g. The prepolymer was transferred to a separate stirrer to make an aqueous dispersion of 70.0 parts by weight of a pre-polymer, followed by 2.0 parts by weight of dimethylaminoethanol, 16.54 parts by weight of en-methyl-2-pyrrolidone, 1.03 parts by weight of hydrazine, and distilled water maintained at 35 ° C. Slowly add 151.93 parts by weight and stir at 500 rpm until a complete dispersion is formed.

The water-dispersed polyurethane resin of the present invention obtained as described above became an aqueous dispersion having a high viscosity having an average particle distribution of 400 to 500 nanometers.

The water-dispersed polyurethane resin is a white water-dispersed resin having a solid content of 29.7%, an acid value of 56 mgKOH / g, a hydroxyl value of 0 mgKOH / g, a pH of 8.24, and a viscosity of grape cup # 4 at 202.

Preparation Example 8

222.0 parts by weight of isophorone diisocyanate, 107.2 parts by weight of dimethylol propionic acid, 0.3 parts by weight of dibutyltin dilaurate, 22.4 parts by weight of en-methyl-2-pyrrolidone in a reactor equipped with a stirrer, a thermometer, a nitrogen injection pipe, and a cooler. Buy wealth.

After reacting for 3 hours while maintaining the 70 ~ 90 ℃ until the reaction is completely reacted. At the end of the reaction, the prepolymer had a residual isocyanate content of 3.8% and an acid value of 142 mgKOH / g. Thereafter, 22.3 parts by weight of normal butanol was added and reacted at 90 ° C. for 30 minutes, and the residual isocyanate content reached 3.8%, and the acid value thereof was 142 mgKOH / g.

Then 22.3 parts by weight of normal butanol was added and the remaining isocyanate was blocked while reacting at 90 ° C. for 30 minutes. Thereafter, the temperature was lowered to 70 ° C., and 40.0 parts by weight of dimethylethanolamine was injected into the prepolymer over 20 minutes, and 466.0 parts by weight of distilled water maintaining 35 ° C. was slowly added, followed by stirring at a high speed until the prepolymer was completely solubilized. The aqueous blocked polyisocyanate resin of the present invention obtained by the above method is a yellow viscous resin having a solid content of 40% acid value of 50 mgKOH / g, a pH of 7 to 9, and a viscosity of 30 pa.s.

Using the water-dispersible resin prepared by the above, the application experiment according to the paint composition change was performed as follows. In the following examples, the fused silica used was Aerosil R972 (Degussa), the dispersant was Sufinol 104E (Air products), the leveling agent was Editol XW 395 (Hoechst), and the associative thickener was used. Bermodol PUR 2100 (Langer) and amino resins are Cymel 303, Cymel 305, Cymel 327, Cymel 1116, Cymel 1123 (Cyanamide), Mafrenal MFC 904, 900, 920 (Cheist), Resmen 714, 717, and 730 (Monsanto) selected and used suitably for the example conditions.

Example 1

3,4: coloring pigment

5,6: sieving pigment

7,14: thickener

10: solvent

13: During composition as hardener

Amino resin less than 10% in the resin composition As shown in the said [Table 1], the composition of 3-11 is premixed for 15 minutes.

Example 2

A water-soluble coating composition was prepared in the same manner as in Example 1 except that parts by weight of the compositions 1 to 15 described in [Table 2] were used.

Comparative Example 1

A water-soluble coating composition was prepared in the same manner as in Example 1 except that parts by weight of the compositions 1 to 15 described in [Table 3] were used.

Comparative Example 2

A water-soluble coating composition was prepared in the same manner as in Example 1 except that parts by weight of the compositions 1 to 15 described in [Table 4] were used.

Comparative Example 3

A water-soluble coating composition was prepared in the same manner as in Example 1 except that parts by weight of the compositions 1 to 15 described in [Table 5] were used.

Comparative Example 4

Amino composition and the weight part of the composition of 1-15 as described in the said [Table 6]

A water-soluble coating composition was prepared in the same manner as in Example 1 except for the use of an amino resin having a content of 10% or more by the same process as in Example 1 above.

Comparative Example 5

A water-soluble coating composition was prepared in the same manner as in Example 1 except that parts by weight of the compositions 1 to 15 described in [Table 7] were used.

Comparative Example 6

A water-soluble coating composition was prepared in the same manner as in Example 1 except that parts by weight of the compositions of 1 to 15 described in Table 8 were used.

Comparative Example 7

A water-soluble coating composition was prepared in the same manner as in Example 1 except that parts by weight of the compositions 1 to 15 described in [Table 9] were used. As a result of forming the coating film through the Examples and Comparative Examples at all times, the results shown in Table 10 were obtained.

* Condition in container: No dust, foreign matter, hard lump, uniformly distributed

* Condition in container: No dust, foreign matter, hard lump and dispersed evenly

* Spray workability: A dry coating thickness of 30μm or more should be applied to obtain a smooth coating film.

* Lower air resistance: Less than 2 craters / 300 × 30mm

* Impact resistance: 20cm / no crack, no volley

* Water resistance: After deposition at 40 ℃ for 240 hours, it is left for 1 hour.

* Alkali resistance, acid resistance: 40 ℃ × 8 hours immersion, 1 hour left / no film phenomenon

* Salt water spray resistance: After 480 hours spray, swell 3mm away from the cross

* Accelerated weather resistance: Gloss, retention rate over 90% after 1,000 hours test / freezing

* Paint shelf life: Within 15% of viscosity change when measuring viscosity at room temperature after 50 ℃ × 72 hours

The water-soluble coating composition made by the method of the present invention has a beautiful appearance to the coating film when it is adapted to the coating film, and has excellent chemical resistance such as water resistance, acid resistance and alkali resistance, excellent storage property of the paint, easy spraying, and excellent impact resistance. The chipping property was very excellent.

Claims (17)

Acid value of 10-90 mgKOH / g, Acid value of 70-150 mgKOH / g, Weight average molecular weight of 3,000-30,000, Water-dispersed polyester resin containing 40-70 weight% of aromatic compounds, Acid value of 5-15 mgKOH / g, 40 A water-dispersed polyurethane polyol resin having a weight average molecular weight of 10,000 to 40,000 with a hydroxyl value of ˜90 mg KOH / g, and a water-dispersible resin composed of an amino resin and a water-dispersed blocked polyisocyanate resin as a curing agent. The method of claim 1, wherein the water-disperse polyester resin is a reaction of the polyhydric alcohol and polyhydric acid at a temperature of 160 ~ 200 ℃, then mixing the co-solvent at 130 ~ 150 ℃ by mixing water and neutralizing agent at a temperature of 100 ℃ or less Dispersed resin, characterized in that prepared. The method of claim 2, wherein the neutralizing agent is one or more selected from the group consisting of diethanolamine, diethylethanolamine, phenol diethanolamine, methyl diethanolamine and dimethyl amino ethanol, A water-dispersible resin, characterized in that used at -10% by weight. The method of claim 2, wherein the co-solvent is one or more selected from the group consisting of 1,4-butylene glycol, ethylene glycol and diethylene glycol, characterized in that used in 10 to 20% by weight of the water-dispersed polyester resin Dispersion resin made into. The method of claim 1, wherein the water-dispersed polyurethane polyol resin reacts a polyhydric alcohol and a polyhydric acid at 100 to 220 ° C to synthesize a polyester polyol, mix with a salted group at 90 to 100 ° C and polyvalent isocyanate at 70 ° C Dispersing resin, characterized in that prepared by adding a neutralizing agent and a co-solvent after forming a polyurethane polyol prepolymer. 6. The water-dispersible resin according to claim 5, wherein the salted group is dimethyl propionic acid and is used at 4 to 7% by weight of the polyurethane polyol prepolymer. The water-dispersible resin according to claim 5, wherein the polyurethane polyol prepolymer has an OH / NCO equivalent ratio of 1.1 to 1.8. The method of claim 5, wherein the neutralizing agent is one or more selected from the group consisting of diethanolamine, diethylethanolamine, dimethylethanolamine, triethylamine, tributylamine, phenyl diethanolamine and methyldiethanolamine, Water dispersion resin, characterized in that used in 1 to 5% by weight based on the water-dispersed polyurethane polyol resin. The method according to claim 5, wherein the co-solvent is one selected from the group consisting of methyl ethyl ketone, acetone, dimethylformamide, glycol ether ester, florinated hydrocarbon, an-methyl-2-pyrrolidone and hydrogenated furan Or more, used in an amount of 6 to 10% by weight based on the water-dispersed polyurethane polyol resin. The water-dispersible resin according to claim 1, wherein the water-dispersed polyester resin and the water-dispersed polyurethane polyol resin are in a 1: 1 to 6: 1 weight ratio. The method of claim 1 wherein the amino resin is A water-dispersion resin, characterized in that the composition component is 10% by weight or less, 10 to 20% by weight in terms of solids relative to the water-dispersed polyester resin. The method of claim 1, wherein the water-blocked polyisocyanate resin reacts polyhydric isocyanate with α, α-dimethylolpropionic acid at 90 to 100 ° C., and after adding a co-solvent, blocking residual NCO with alcohol, neutralizing agent and water. Dispersed resin, characterized in that prepared by the addition. 13. The aqueous dispersion polyisocyanate resin according to claim 12, wherein the co-solvent is at least one selected from the group consisting of methyl ethyl ketone, acetone, dimethylformamide, glycol ether ester and an-methyl-2-pyrrolidone. Water dispersion resin, characterized in that used in 2 to 5% by weight relative to. The method according to claim 12, wherein the content of residual NCO is 3 to 6%, and the alcohol blocking the remaining NCO is isopropanol, n-propanol, n-butanol, n-pentanol, 2-ethylhexanol, 2-e. A water-dispersible resin, characterized in that one is selected from the group consisting of oxyethanol and cyclohexanol. The water dispersion resin according to claim 1, wherein the water dispersion polyisocyanate resin has an acid value of 50 mgKOH / g, a pH of 7 to 9, a viscosity of 30 pa.s, and a solid content of 40%. The water-dispersible resin according to claim 1, wherein the water-disperse polyester resin to the amino resin is used in a solid ratio of 90:10 to 80:20. The water-dispersible resin according to claim 1, wherein the water-dispersed polyurethane polyol resin to the water-dispersed blocked polyisocyanate resin is used in a solid ratio of 70:30 to 60:30.