JP2006348103A - Water-based heat resistant resin composition and coating using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water-based heat resistant resin composition which gives a coating film having an excellent appearance equal to that obtained from the conventional organic solvent-type polyamide resin solutions, has a reduced content of an organic solvent, does not cause environmental pollutions and deterioration of work environments and is advantageous in terms of safety and hygiene and a coating composed of the resin composition as a coating film component. <P>SOLUTION: The water-based heat resistant resin composition is obtained by mixing (A) a polyimide resin obtained by reacting a diisocyanate compound or a diamine compound with a tribasic acid anhydride or a tribasic acid anhydride chloride in a basic polar solvent, (B) N,N,N',N'-tetramethyl hexanediamine and (C) water. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an aqueous heat-resistant resin composition and a paint using the same. More specifically, the present invention relates to a water-based heat-resistant resin composition that reduces organic solvent content by containing water, has no environmental pollution or deterioration of the working environment, and is advantageous for safety and hygiene, and a paint that uses it as a coating film component. .

Aqueous resin solutions that use water as a medium instead of organic solvents in terms of environmental protection, safety and health, economy, and painting workability have attracted attention, and polyamides that act on carboxyl groups remaining at the resin ends and basic compounds A method for water-solubilizing an imide resin has been reported (for example, JP-A-2002-284993).
However, the water-soluble polyamide-imide resin produced by the above method tends to deteriorate the appearance of the coating film when it is applied to the substrate and cured, so that the appearance of the coating film is likely to deteriorate. Development of a low-foaming water-soluble paint having an excellent appearance is strongly desired.

JP 2002-284993 A

  The object of the present invention is to have a good appearance equivalent to that of a conventional organic solvent-type polyamideimide resin solution when it is used as a coating film, and to reduce the content of the organic solvent by the inclusion of water, thereby deteriorating environmental pollution and the working environment. It is an object of the present invention to provide a water-based heat-resistant resin composition that is advantageous in terms of safety and hygiene, and a coating material using this as a coating film component.

Polyamide obtained by reacting diisocyanate compound or diamine compound with tribasic acid anhydride or tribasic acid anhydride chloride as a result of investigation on the preparation method of the aqueous heat-resistant resin composition solution having good coating film appearance. By using N, N, N ′, N′-tetramethylhexanediamine when water-solubilizing the imide resin, a good appearance equivalent to that of the conventional organic solvent-type polyamideimide resin solution is achieved, and organic The present inventors have found that it is possible to contribute to the environment by reducing the solvent, and have reached the present invention.
That is, the present invention relates to (1) (A) a polyamideimide resin obtained by reacting a diisocyanate compound or a diamine compound with a tribasic acid anhydride or a tribasic acid anhydride chloride in a basic polar solvent (B) ) N, N, N ', N'-tetramethylhexanediamine and (C) an aqueous heat-resistant resin composition comprising water.
Further, in the present invention, (2) N, N, N ′, N′-tetramethylhexanediamine as the component (B) is a carboxyl group contained in the polyamideimide resin as the component (A) and in the polyamideimide resin. It is related with the water-based heat resistant resin composition as described in said (1) which mix | blended 1-20 equivalent with respect to the acid value which match | combined the carboxyl group which opened the acid anhydride group.
In addition, the present invention provides (3) (1) wherein the water of component (C) is blended in an amount of 5 to 99% by weight based on the total amount of component (A), component (B) and component (C). Or it is related with the water-based heat-resistant resin composition as described in said (2).
The present invention also includes (4) the number average molecular weight of the polyamideimide resin of component (A) is 5,000 to 50,000, and a carboxyl group obtained by ring-opening a carboxyl group and an acid anhydride group. Further, the present invention relates to the water-based heat-resistant resin composition according to any one of (1) to (3) above, wherein the acid value is 10 to 100.
Furthermore, the present invention relates to (5) a paint comprising the aqueous heat-resistant resin composition according to any one of (1) to (4) as a coating film component.

  If the water-based heat-resistant resin composition of the present invention is used, a coating film having a good appearance can be formed and can be suitably used for insulating coatings and protective coatings on various substrates. In addition, the water-based heat-resistant resin composition of the present invention reduces the organic solvent content, has no environmental pollution or deterioration of the working environment, and has great benefits for health and safety.

  The polyamideimide resin used in the present invention is obtained by reacting a diisocyanate compound or diamine compound with a tribasic acid anhydride or tribasic acid anhydride chloride as described above. The diisocyanate compound or diamine compound and the tribasic acid anhydride or tribasic acid chloride are preferably aromatic compounds. The typical compounds used in the above reaction are listed below.

  Examples of the diisocyanate compound include 4,4′-diphenylmethane diisocyanate, xylylene diisocyanate, 3,3′-diphenylmethane diisocyanate, and paraphenylene diisocyanate.

Examples of the diamine compound include 4,4′-diaminodiphenyl ether, 4,4′-diaminodiphenyl sulfone, 3,3′-diaminodiphenyl sulfone, xylylenediamine, and phenylenediamine.
Examples of the tribasic acid anhydride include trimellitic acid anhydride and the like, and examples of the tribasic acid anhydride chloride include trimellitic acid anhydride chloride and the like.

When synthesizing the polyamideimide resin, dicarboxylic acid, tetracarboxylic dianhydride, and the like can be reacted at the same time as long as the properties of the polyamideimide resin are not impaired.
Examples of the dicarboxylic acid include terephthalic acid, isophthalic acid, and adipic acid. Examples of the tetracarboxylic dianhydride include pyromellitic dianhydride, benzophenone tetracarboxylic dianhydride, and biphenyltetracarboxylic dianhydride. Is mentioned.
The diisocyanate compound or diamine compound, tribasic acid anhydride or tribasic acid anhydride chloride and the amount of dicarboxylic acid and tetracarboxylic dianhydride used as required are the molecular weight of the polyamideimide resin produced, From the viewpoint of the degree of cross-linking, the diisocyanate compound or diamine compound is preferably 0.8 to 1.1 mol, more preferably 0.95 to 1.08 mol with respect to 1.0 mol of the total amount of acid components. In particular, it is preferable to use 1.0 to 1.08 mol. Moreover, it is preferable that dicarboxylic acid and tetracarboxylic dianhydride are used in the acid component in the range whose total amount is 0-50 mol%.

  The polyamideimide resin used in the present invention reacts a diisocyanate compound or diamine compound with a tribasic acid anhydride or tribasic acid anhydride chloride in a basic polar solvent. Here, as the basic polar solvent, N-methyl-2-pyrrolidone, dimethylacetamide, dimethylformamide, and the like can be used. In order to perform the polyamide imidization reaction at a high temperature in a short time, N-methyl- It is preferable to use a high boiling point solvent such as 2-pyrrolidone. Moreover, there is no restriction | limiting in particular in the usage-amount of a solvent, However, It is preferable to set it as 100-500 weight part with respect to 100 weight part of total amounts of a diisocyanate component and an acid component. The conditions for synthesizing the polyamide-imide resin are various and cannot be generally specified, but are usually performed at a temperature of 120 to 155 ° C., and in an atmosphere such as nitrogen in order to reduce the influence of moisture in the air. preferable.

The polyamideimide resin used in the present invention preferably has a number average molecular weight of 5,000 to 50,000. When the number average molecular weight is less than 5,000, various properties such as heat resistance and mechanical properties of the coating film tend to decrease when it is used as a coating film. When dissolved in a solvent, the viscosity increases and the workability during coating tends to be poor. Therefore, the number average molecular weight of the polyamideimide resin is preferably 10,000 to 30,000, and particularly preferably 15,000 to 25,000.
The number average molecular weight of the polyamideimide resin is sampled at the time of resin synthesis, measured by gel permeation chromatography (GPC) using a standard polystyrene calibration curve, and the synthesis is continued until the target number average molecular weight is reached. Therefore, it is managed within the above range.

Moreover, it is preferable that the acid value (KOHmg / g) which combined the carboxyl group which ring-opened the carboxyl group and the acid anhydride group is 10-100, and the carboxyl group which reacts with a basic compound as it is less than 10 Therefore, water-solubilization becomes difficult, and when it exceeds 100, the finally obtained water-based heat-resistant resin composition is easily gelled over time. From this, it is more preferable that the combined acid value of the carboxyl group obtained by ring opening of the carboxyl group and the acid anhydride group is 20 to 80, and particularly preferably 30 to 60.
In addition, the acid value combining the carboxyl group of the polyamideimide resin and the carboxyl group obtained by ring opening of the acid anhydride group can be obtained by the following method. First, about 0.5 g of polyamideimide resin is taken, about 0.15 g of 1,4-diazabicyclo [2,2,2] octane is added thereto, and about 60 g of N-methyl-2-pyrrolidone and ion-exchanged water are added. Add about 1 ml and stir until the polyamideimide resin is completely dissolved. This is titrated with a potentiometric titrator using a 0.05 mol / l ethanolic potassium hydroxide solution to obtain an acid value that combines the carboxyl groups of the polyamideimide resin and the carboxyl groups obtained by ring opening of the acid anhydride groups. .

N, N, N ′, N′-tetramethylhexanediamine is an acid value obtained by combining a carboxyl group and a ring-opened acid anhydride group contained in a polyamideimide resin obtained by reacting in the above organic solvent. 1 to 20 equivalents are preferably used. If the amount is less than 1 equivalent, water-solubilization of the resin becomes difficult. If the amount exceeds 20 equivalents, hydrolysis of the resin is promoted, and the viscosity or properties may be lowered by long-term storage. From this, it is more preferable to set it as 3-15 equivalent with respect to the acid value which match | combined the carboxyl group which ring-opened the carboxyl group and the acid anhydride group, and it is especially preferable to set it as 6-12 equivalent.
N, N, N ′, N′-tetramethylhexanediamine forms a hydrophilic group by forming a salt with the carboxyl group at the terminal of the polyamideimide resin. The salt formation may be performed in the presence of water, or water may be added after adding N, N, N ′, N′-tetramethylhexanediamine. The temperature for forming the salt is 0 ° C to 200 ° C, preferably 40 ° C to 130 ° C.
Depending on the amount of N, N, N ′, N′-tetramethylhexanediamine and the method of adding water, the resulting aqueous resin composition is in the form of an emulsion, translucent solution, transparent solution, etc., but storage stability, From the viewpoint of coating workability, it is preferable to use a translucent or transparent solution.

  As the water of the component (C), ion-exchanged water is preferably used, and preferably 5 to 99% by weight, more preferably 20 to 20% with respect to the total amount of the component (A), the component (B), and the component (C). 60% by weight is blended. If the blending amount is less than 5% by weight, it is not generally referred to as a water-soluble polymer because it contains less water. If it exceeds 99% by weight, it tends not to function as a paint.

The water-based heat-resistant resin composition thus obtained is diluted to an appropriate concentration as needed when used. Diluent solvents include polar solvents such as water, dimethylformamide, dimethylacetamide, dimethyl sulfoxide, N-methyl-2-pyrrolidone, as cosolvents, polyols, their lower alkyl etherified products, acetylated products, etc. May be used. For example, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, glycerin, trimethylolpropane, isopropyl alcohol, or a monomethyl etherified product thereof, a monoethyl ether product, a monoisopropyl etherified product, a monobutyl etherified product, a dimethyl etherified product, and a monovalent product thereof. An acetylated product or the like is used.
The water-based heat-resistant resin composition according to the present invention is applied to a substrate and cured to form a coating film on the surface of the substrate.

Next, examples of the present invention will be described. However, the present invention is not limited to these examples, and it is needless to say that the present invention includes many other embodiments based on the gist of the invention.
Example 1
1106.2 g of trimellitic anhydride as tribasic acid anhydride, 1455.8 g of 4,4-diphenylmethane diisocyanate as diisocyanate compound, 2562.0 g of N-methyl-2-pyrrolidone as basic polar solvent, thermometer, stirrer, condenser The mixture was gradually warmed up to 130 ° C. over about 2 hours while stirring in a dry nitrogen stream. The temperature was kept at 130 ° C. while paying attention to the sudden foaming of carbon dioxide gas generated by the reaction, and the heating was continued for about 6 hours, and then the reaction was stopped to obtain a polyamideimide resin solution of component (A).
The polyamideimide resin solution had a nonvolatile content (200 ° C.-2 h) of about 50% by weight and a viscosity (30 ° C.) of about 85.0 Pa · s. The number average molecular weight of the polyamideimide resin was about 17,000, and the acid value of the carboxyl group obtained by ring-opening the carboxyl group and the acid anhydride group was about 40 KOHmg / g. The number average molecular weight was measured under the following conditions.
Model: Hitachi L6000
Detector: Hitachi L4000 type UV
Wavelength: 270nm
Data processor: ATT 8
Column: Gelpack GL-S300MDT-5 × 2
Column size: Diameter 8mm x 300mm
Solvent: DMF / THF = 1/1 (liter) + phosphoric acid 0.06M + lithium bromide 0.06M
Sample concentration: 5 mg / 1 ml
Injection volume: 5 μl
Pressure: 49 kgf / cm ² (4.8 × 10 ⁶ Pa)
Flow rate: 1.0 ml / min
2,700.0 g of this polyamideimide resin solution (component (A)) was put into a flask equipped with a thermometer, a stirrer, and a cooling tube, and gradually heated to 50 ° C. while stirring in a dried nitrogen stream. Raised. When the temperature reached 50 ° C., 1658.6 g (10 equivalents) of N, N, N ′, N′-tetramethylhexanediamine (component (B)) was added, and the mixture was sufficiently stirred while being kept at 50 ° C., and then stirred. While adding ion exchange water gradually. Finally, ion-exchanged water (component (C)) was added until reaching 1868.0 g (30 wt%) to obtain a transparent and uniform aqueous heat-resistant resin composition.

(Example 2)
In a dry nitrogen stream, 382.9 g of trimellitic anhydride, 503.9 g of 4,4'-diphenylmethane diisocyanate, and 886.8 g of N-methyl-2-pyrrolidone were placed in a flask equipped with a thermometer, stirrer, and condenser. The temperature was gradually raised to 80 ° C. over about 1 hour with stirring. The temperature was kept at 80 ° C. while paying attention to the sudden foaming of carbon dioxide gas generated by the reaction, and the heating was continued for about 7 hours from the start of heating, and then the reaction was stopped to obtain a polyamideimide resin solution.
The polyamideimide resin solution had a nonvolatile content (200 ° C.-2 h) of about 50% by weight and a viscosity (30 ° C.) of about 80.0 Pa · s. The number average molecular weight of the polyamideimide resin was about 15,000, and the acid value of the carboxyl group obtained by ring-opening the carboxyl group and the acid anhydride group was about 50.
200 g of this polyamideimide resin solution was put into a flask equipped with a thermometer, a stirrer, and a cooling tube, and gradually heated to 90 ° C. while stirring in a dried nitrogen stream. When the temperature reached 90 ° C., 92.1 g (6 equivalents) of N, N, N ′, N′-tetramethylhexanediamine was added, and after sufficiently stirring while maintaining at 90 ° C., ion-exchanged water was gradually added while stirring. Was added. Finally, ion-exchanged water was added until the amount reached 194.7 g (40% by weight) to obtain a transparent and uniform aqueous heat-resistant resin composition.

(Comparative Example 1)
Nitrogen obtained by adding 876.9 g of trimellitic anhydride, 1153.8 g of 4,4′-diphenylmethane diisocyanate and 4,738.3 g of N-methyl-2-pyrrolidone to a flask equipped with a thermometer, a stirrer and a condenser. The temperature was gradually raised to 110 ° C. over about 1 hour with stirring in an air stream. The temperature was gradually raised to 120 ° C. while paying attention to the sudden foaming of carbon dioxide generated by the reaction. After continuing the heating for about 8 hours from the start of heating, the reaction was stopped to obtain a polyamideimide resin solution.
The polyamideimide resin solution had a nonvolatile content (200 ° C.-2 h) of about 30% by weight and a viscosity (30 ° C.) of about 1.8 Pa · s. Further, the number average molecular weight of the polyamideimide resin was about 21,000, and the acid value of the combined carboxyl group obtained by ring opening of the carboxyl group and the acid anhydride group was about 35.

(Comparative Example 2)
500 g of the polyamideimide resin solution obtained in Comparative Example 1 was put into a flask equipped with a thermometer, a stirrer, and a cooling tube, and gradually heated up to 40 ° C. while stirring in a dried nitrogen stream. It was. When the temperature reached 40 ° C., 75.8 g (8 equivalents) of triethylamine was added, and after sufficiently stirring while maintaining the temperature at 40 ° C., ion-exchanged water was gradually added while stirring. Finally, ion-exchanged water was added to 144.0 g (20% by weight) to obtain a transparent and uniform aqueous heat-resistant resin composition.

Test Example The transparent and uniform water-based heat-resistant resin composition obtained in Examples 1 and 2 and Comparative Examples 1 and 2 was used as a coating material on an aluminum substrate (JIS H4000 compliant product, A1050P) having a thickness of 1 mm. After coating, baking was performed at 300 ° C. for 30 minutes to form a coating film plate having a film thickness of about 15 μm, and the appearance of the coating film was visually confirmed. The evaluation results are shown in Table 1.

１）○：発泡が無く平滑で均一な塗膜で外観が良好
×：発泡が生じ外観不良
表１から、実施例１及び２で得られた塗料は、系内に水を含有する水系耐熱性樹脂組成物でありながら比較例１の溶剤型塗料と同等の良好な外観を有していることが分る。また、トリエチルアミンを使用した比較例２は塗膜に発泡が生じ外観が不良となった。

1) Good: Appearance is good with a smooth and uniform coating without foaming x: Poor appearance due to foaming From Table 1, the paints obtained in Examples 1 and 2 are water-based heat-resistant containing water in the system Although it is a resin composition, it turns out that it has the same favorable external appearance as the solvent-type coating material of the comparative example 1. In Comparative Example 2 using triethylamine, foaming occurred in the coating film and the appearance was poor.

Claims (5)

(A) Polyamideimide resin obtained by reacting a diisocyanate compound or diamine compound with a tribasic acid anhydride or tribasic acid anhydride chloride in a basic polar solvent, and (B) N, N, N ′, An aqueous heat-resistant resin composition comprising N'-tetramethylhexanediamine and (C) water. (B) Component N, N, N ′, N′-tetramethylhexanediamine opened the carboxyl group contained in the polyamideimide resin of component (A) and the acid anhydride group in the polyamideimide resin. The water-based heat-resistant resin composition according to claim 1, wherein 1 to 20 equivalents are blended with respect to the acid value combined with the carboxyl group. The water-based heat resistance according to claim 1 or 2, wherein the water of component (C) is blended in an amount of 5 to 99% by weight based on the total amount of component (A), component (B) and component (C). Resin composition. The number average molecular weight of the (A) component polyamideimide resin is 5,000 to 50,000, and the acid value of the carboxyl group obtained by ring-opening the carboxyl group and the acid anhydride group is 10 to 100. The water-based heat resistant resin composition according to any one of claims 1 to 3. The coating material which uses the water-based heat-resistant resin composition in any one of Claim 1 thru | or 4 as a coating-film component.