JP2011236385A - Heat-resistant resin composition and paint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat-resistant resin composition capable of forming a water-soluble highly-strong coating.SOLUTION: This heat-resistant resin composition is formed by blending a polyamideimide resin obtained by reacting (A) 3, 3'-dimethylbiphenyl-4, 4'-diisocyanate with an aromatic tribasic acid anhydride in a polar solvent, (B) a basic compound and (C) water.

Description

  The present invention relates to a heat resistant resin composition and a paint.

  In recent years, water-based resin solutions that use water as a medium instead of organic solvents have attracted attention in terms of environmental protection, safety and health, economy, and painting workability, and act on carboxyl groups and basic compounds remaining at the end of the resin. A method for water-solubilizing a polyamideimide resin to be used has been reported (for example, Patent Document 1) and applied to various applications.

  As this water-soluble polyamideimide resin is developed for various uses, various characteristics are being required depending on the use. For example, it is possible to form a high-strength coating film and to have high adhesion during high-temperature firing.

Japanese Patent No. 3491624

  However, most of the conventional water-soluble polyamideimide resins are hydrophobic in the polyamideimide resin skeleton, and the structure, monomer blending amount, and number average molecular weight have been limited to make them water-soluble. Therefore, water-soluble polyamide-imide resins having characteristics that can be differentiated have been considered difficult. An object of the present invention is to provide a heat-resistant resin composition capable of forming a water-soluble and high-strength coating film.

As a result of examining the heat-resistant resin composition capable of forming a water-soluble and high-strength coating film as described above, the polyamideimide resin contains a specific monomer and has an appropriate molecular weight and is basic when water-solubilized. The present invention finds that it is possible to form a water-soluble and high-strength coating film in comparison with a coating film obtained from a conventional water-based polyamideimide resin by blending an appropriate amount of a compound and water. It came to.
That is, the present invention relates to the following.
1. (A) Polyamideimide resin obtained by reacting 3,3′-dimethylbiphenyl-4,4 ′ diisocyanate with an aromatic tribasic acid anhydride in a polar solvent, (B) a basic compound, and (C) A heat resistant resin composition comprising water.
2. Item (A) The number average molecular weight of the polyamideimide resin is 10,000 to 35,000, and the acid value obtained by ring opening of the carboxyl group and the acid-base acid anhydride group to combine the carboxyl groups is 20 to 60. The heat resistant resin composition described in 1.
3. Item (1) or (2) wherein the blending amount of component (B) is 3 to 10 equivalents with respect to the acid value of the combined carboxyl group and ring-opened acid anhydride group contained in (A) polyamideimide resin. The heat resistant resin composition according to any one of the above.
4). Item 4. The heat resistance according to any one of Items 1 to 3, wherein the water content of the component (C) is 30 to 80% by weight based on the total amount of the components (A), (B), and (C). Resin composition.
5). Item 5. A paint comprising the heat-resistant resin composition according to any one of Items 1 to 4 as a coating film component.
6). Claim | item 1-5 base material which apply | coated and hardened the heat resistant resin composition in any one.

  By using the heat resistant resin composition of the present invention, it becomes possible to obtain a coating film having a higher strength than a coating film obtained from a conventional heat resistant resin composition. These have great benefits for various applications that require coating hardness.

(A) Polyamideimide resin obtained by reacting 3,3′-dimethylbiphenyl-4,4 ′ diisocyanate with an aromatic tribasic acid anhydride in a polar solvent, (B) a basic compound, and (C) It is characterized by containing water. By setting it as the above compositions, it becomes possible to form a water-soluble and high-strength coating film.

  N-methyl-2-pyrrolidone, γ-butyrolactone, dimethylacetamide or dimethylformamide can be used as the polar solvent used in the polymerization of the (A) polyamideimide resin used in the present invention. In order to carry out at high temperature for a short time, it is preferable to use a high boiling point solvent such as N-methyl-2-pyrrolidone. Moreover, although there is no restriction | limiting in the usage-amount of a solvent, it is preferable from a soluble viewpoint of resin to set it as 50-500 weight part with respect to 100 weight part of total amounts of an isocyanate component or an amine component, and an acid component. The conditions for synthesizing the polyamide-imide resin are various and cannot be specified in general, but it is usually performed at a temperature of 80 to 180 ° C., and is preferably performed in an atmosphere such as nitrogen in order to reduce the influence of moisture in the air. .

  (A) In addition to 3,3′-dimethylbiphenyl-4,4 ′ diisocyanate, other diisocyanate compounds such as 4,4′-diphenylmethane diisocyanate, xylylene diisocyanate are used as isocyanate components used for polymerization of polyamideimide resin. 3,3′-diphenylmethane diisocyanate, 3,3′-dimethoxybiphenyl-4,4′-diisocyanate, paraphenylene diisocyanate, hexamethylene diisocyanate, tolylene diisocyanate, naphthalene diisocyanate, tolylene diisocyanate and the like may be used in combination. In this case, it is preferable to set it to 90 equivalent% or less of the total isocyanate component so as not to impair the properties of the polyamideimide resin of the present invention.

Examples of the aromatic tribasic acid anhydride include trimellitic acid anhydride. In the present invention, when a polyamideimide resin is synthesized, 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 amount of the diisocyanate compound, tribasic acid anhydride, and dicarboxylic acid and tetracarboxylic dianhydride used as required is the total amount of acid components from the viewpoint of the molecular weight of the polyamideimide resin produced and the degree of crosslinking. The diisocyanate compound is preferably 0.8 to 1.1 mol, more preferably 0.95 to 1.08 mol, particularly 1.0 to 1.08 mol based on 0 mol. It is preferable.

  In the acid component, dicarboxylic acid and tetracarboxylic dianhydride are preferably used in a total amount of 0 to 50 mol% from the viewpoint of maintaining the properties of the polyamideimide resin.

  The (A) polyamideimide resin used in the present invention preferably has a number average molecular weight of 10,000 to 35,000. If the number average molecular weight is less than 10,000, the strength of the coating film tends to decrease, and if it exceeds 35,000, the solubility in water tends to decrease. From these viewpoints, the number average molecular weight of the polyamideimide resin is preferably 20,000 to 30,000, and more preferably 23,000 to 27,000.

  The number average molecular weight of the (A) polyamideimide resin is sampled during resin synthesis and measured by gel permeation chromatograph (GPC) using a standard polystyrene calibration curve until the target number average molecular weight is reached. The range is managed by continuing the synthesis.

  The (A) polyamideimide resin used in the present invention preferably has an acid value of 20 to 60 mgKOH / g, which is a combination of carboxyl groups obtained by ring opening of carboxyl groups and acid anhydride groups. When it is 20 mgKOH / g or more, the carboxyl group that reacts with the basic compound is sufficient, and water-solubilization tends to be facilitated. Moreover, the heat resistant resin composition finally obtained as it is 60 mgKOH / g or less becomes difficult to gelatinize by passage of time. From these viewpoints, it is more preferable that the acid value of the carboxyl group obtained by ring-opening the carboxyl group and the acid anhydride group is 25 to 40 mgKOH / g.

  In addition, the acid value which combined the carboxyl group which ring-opened the carboxyl group and acid anhydride group of (A) polyamide-imide resin can be obtained with the following method. First, (A) about 0.5 g of polyamideimide resin is added, 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 ions are added. Add about 1 ml of exchange water and stir until (A) 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. .

  In the present invention, as the basic compound (B), triethylamine, tributylamine, N, N-dimethylcyclohexylamine, N, N-dimethylbenzylamine, triethylenediamine, N-methylmorpholine, N, N, N ′, N '-Tetramethylethylenediamine, N, N, N', N ", N" -pentamethyldiethylenetriamine, N, N ', N'-trimethylaminoethylpiperazine, diethylamine, diisopropylamine, dibutylamine, ethylamine, isopropylamine, butylamine Alkylamine, monoethanolamine, diethanolamine, triethanolamine, dipropanolamine, tripropanolamine, N-ethylethanolamine, N, N-dimethylethanolamine, N, N-diethylethane Ruamin, cyclohexanol amine, N- methyl-cyclohexanol, alkanolamines such as N- benzyl ethanolamine are suitable. In addition to the above basic compound, for example, a caustic alkali such as sodium hydroxide or potassium hydroxide or aqueous ammonia may be used in combination.

  Moreover, it is preferable to use 3-10 equivalent of (B) basic compound with respect to the acid value which combined the carboxyl group and ring-opened acid anhydride group which are contained in (A) polyamide-imide resin. If it is 3 equivalents or more, water-solubilization of the resin becomes easy, and if it is 10 equivalents or less, the strength of the coating film tends to be improved. From these viewpoints, the acid value is preferably 4 to 8 equivalents relative to the combined acid value of the carboxyl group obtained by ring-opening the carboxyl group and the acid anhydride group.

  (B) The basic compound forms a salt with the carboxyl group at the end of (A) the polyamideimide resin to become a hydrophilic group. As a method for forming a salt, (A) component, (B) component and (C) water described later may be mixed at 10 ° C. to 150 ° C., or (A) component and (B) component may be mixed. After that, (C) water described later may be added at the above temperature. As for the temperature which forms a salt, 30 to 100 degreeC is more preferable.

  The heat resistant resin composition of the present invention contains (C), and ion exchange water is preferably used as (C). (C) As for the compounding quantity of a component, 30-80 weight% is preferable with respect to the total amount of (A) component, (B) component, and (C) component. If the blending amount is 30% by weight or more, the water content is sufficient because the contained water is sufficient, and if it is 80% by weight or less, gelation or turbidity tends not to occur. From these viewpoints, the amount is more preferably 40 to 60% by weight.

  The heat-resistant resin composition obtained in this way is diluted to an appropriate concentration as necessary when used. In addition to polar solvents such as N-methyl-2-pyrrolidone, γ-butyrolactone, dimethyl sulfoxide, dimethylacetamide or dimethylformamide as diluent solvents, ether compounds such as anisole, diethyl ether and ethylene glycol as cosolvents Alternatively, ketone compounds such as acetophenone, methyl ethyl ketone, and methyl isobutyl ketone, and alcohols such as ethanol and 2-propanol may be used.

  The heat-resistant resin composition according to the present invention or a coating material comprising the heat-resistant resin composition as a coating film component is applied to a coating object and cured to form a coating film on the surface of the coating object. In particular, the heat-resistant resin composition according to the present invention can form a high-strength coating film as compared with the conventional heat-resistant resin composition, so that the coating film can be used like home appliances, kitchen appliances, and OA members. It has great benefits for various applications that require high durability. In addition, since it contains water, it can be easily mixed with both water-based and solvent-based materials, and the amount of organic solvent that volatilizes outside the system during coating film formation can also be reduced. The benefit of the resin composition is high.

  EXAMPLES 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 many other embodiments based on the gist of the invention are included.

  Put 518.7 g of trimellitic anhydride, 713.6 g of 3,3′-dimethylbiphenyl-4,4 ′ diisocyanate, and 1848.5 g of N-methyl-2-pyrrolidone in a flask equipped with a thermometer, stirrer, and condenser. While stirring in a dried nitrogen stream, the temperature was gradually raised over 2 hours to 140 ° C. The temperature was kept at 140 ° C. while paying attention to the sudden foaming of carbon dioxide gas generated by the reaction, and the reaction was stopped after continuing the heating for 6 hours to obtain a polyamideimide resin solution.

This polyamideimide resin solution had a nonvolatile content (200 ° C.-2 h) of 40% by weight and a viscosity (30 ° C.) of 85.4 Pa · s. The number average molecular weight of the polyamideimide resin was 20,000, and the acid value of the carboxyl group obtained by ring-opening the carboxyl group and the acid anhydride group was 45. 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: 8mmφ × 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

  2,500 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 70 ° C. while stirring in a dried nitrogen stream. When the temperature reached 70 ° C., 324.7 g (4 equivalents) of triethylamine was added, and after sufficiently stirring while maintaining at 70 ° C., ion-exchanged water was gradually added while stirring. Finally, ion-exchanged water was added until the amount reached 1502.2 g (solvent ratio 50% by weight) to obtain a transparent and uniform heat-resistant resin composition.

960.6 g of trimellitic anhydride, 800.8 g of 3,3′-dimethylbiphenyl-4,4 ′ diisocyanate, 505.5 g of 4,4′-diphenylmethane diisocyanate, 2770.7 g of N-methyl-2-pyrrolidone, The mixture was placed in a flask equipped with a stirrer and a condenser, and gradually heated to 90 ° C. over 1 hour while stirring in a dried nitrogen stream. The temperature was kept at 90 ° C. while paying attention to the sudden foaming of carbon dioxide gas generated by the reaction, and after continuing the heating for 8 hours from the start of the heating, the reaction was stopped to obtain a polyamideimide resin solution.
This polyamideimide resin solution had a nonvolatile content (200 ° C.-2 h) of 45% by weight and a viscosity (30 ° C.) of 130.0 Pa · s. The number average molecular weight of the polyamideimide resin was 27,000, and the acid value of the carboxyl group obtained by ring-opening the carboxyl group and the acid anhydride group was 38.
3,200 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., 521.6 g (6 equivalents) of N, N-dimethylethanolamine was added, and after sufficiently stirring while maintaining at 90 ° C., ion-exchanged water was gradually added while stirring. Finally, ion-exchanged water was added until the amount reached 1174.5 g (solvent ratio 50% by weight) to obtain a transparent and uniform heat-resistant resin composition.

379.6 g of trimellitic anhydride, 156.8 g of 3,3′-dimethylbiphenyl-4,4 ′ diisocyanate, 352.6 g of 4,4′-diphenylmethane diisocyanate, 1217.8 g of N-methyl-2-pyrrolidone, The mixture was placed in a flask equipped with a stirrer and a condenser, and gradually heated to 120 ° C. over 1 hour with stirring in a dried nitrogen stream. The temperature was gradually raised to 130 ° C. while paying attention to the sudden bubbling of carbon dioxide gas generated by the reaction, and after 5 hours from the start of heating, the reaction was stopped to obtain a polyamideimide resin solution.
This polyamideimide resin solution had a nonvolatile content (200 ° C.-2 h) of 42% by weight and a viscosity (30 ° C.) of 120.6 Pa · s. The number average molecular weight of the polyamideimide resin was 35,000, and the acid value of the carboxyl group and the acid anhydride group combined was 30.
800 g of this polyamideimide resin solution was placed in 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. When the temperature reached 50 ° C., 168.5 g (8 equivalents) of N, N-diethylethanolamine was added, and the mixture was sufficiently stirred while being kept at 50 ° C. Then, ion-exchanged water was gradually added while stirring. Finally, ion-exchanged water was added until 695.3 g (solvent ratio 60 wt%) to obtain a transparent and uniform heat-resistant resin composition.

Comparative Example 1
106.2 g of trimellitic anhydride, 1455.8 g of 4,4-diphenylmethane diisocyanate, and 2562.0 g of N-methyl-2-pyrrolidone were placed in a flask equipped with a thermometer, a stirrer, and a cooling tube, and dried in a nitrogen stream. The temperature was gradually raised to 130 ° C. over 2 hours with stirring. 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 6 hours, and the reaction was stopped to obtain a polyamideimide resin solution.
The polyamideimide resin solution had a nonvolatile content (200 ° C.-2 h) of 50% by weight and a viscosity (30 ° C.) of 85.0 Pa · s. The number average molecular weight of the polyamideimide resin was 17000, and the acid value of the carboxyl group obtained by ring-opening the carboxyl group and the acid anhydride group was 40.
2,700 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 50 ° C. while stirring in a dried nitrogen stream. When the temperature reached 50 ° C., 447.1 g (4 equivalents) of triethylamine was added, and after sufficiently stirring while maintaining the temperature at 50 ° C., ion-exchanged water was gradually added while stirring. Finally, ion-exchanged water was added until it reached 1348.8 g (solvent ratio: 50% by weight) to obtain a transparent and uniform heat-resistant resin composition.

Test Example The heat resistant resin composition obtained in Examples 1, 2, and 3 and Comparative Example 1 was applied on a glass substrate, and the mechanical properties were measured.

Pencil Hardness The substrates coated with the heat-resistant resin compositions obtained in Examples 1, 2, and 3 and Comparative Example 1 were pre-dried at 80 ° C. for 10 minutes, and then heat-cured at 270 ° C. for 30 minutes to obtain a coating thickness. A coating film having an average value of 20 μm at five locations was obtained. The coating film was shaved with a pencil, and the hardness of the pencil at the time of scratching was recorded.
[Mechanical properties]
The substrates coated with the heat-resistant resin compositions obtained in Examples 1, 2, and 3 and Comparative Example 1 were pre-dried at 80 ° C. for 10 minutes and then heat-cured at 270 ° C. for 30 minutes. A coating film having an average value of 20 μm, a width of 10 mm, and a length of 60 mm was obtained. The obtained coating film was subjected to a tensile test using a tensile tester (Autograph AGS-5 kG manufactured by Shimadzu Corporation) under the conditions of a length between chucks of 20 mm and a tensile speed of 5 mm / min, and mechanical characteristics were obtained.

The results are shown in Table 1.

  Compared with the coating film produced from the heat resistant resin composition obtained in Comparative Example 1, the coating film produced from the heat resistant resin composition obtained in Examples 1, 2, and 3 from Table 1, It was found that the strength after curing was greatly improved. From these results, it can be seen that by using the heat-resistant resin composition of the present invention, it is possible to obtain a coating film having excellent strength as compared with the conventional water-soluble heat-resistant resin composition. From this, it is clear that it has a great benefit for various uses such as home appliances, kitchen appliances, and OA members that require durability of the coating film.

Claims (6)

  (A) Polyamideimide resin obtained by reacting 3,3′-dimethylbiphenyl-4,4 ′ diisocyanate with an aromatic tribasic acid anhydride in a polar solvent, (B) a basic compound, and (C) A heat resistant resin composition comprising water.   (A) The number average molecular weight of the polyamideimide resin is 10,000 to 35,000, and the acid value obtained by ring opening of the carboxyl group and the acid-base acid anhydride group to combine the carboxyl groups is 20 to 60. 1. The heat resistant resin composition according to 1.   (B) The compounding quantity of a component is 3-10 equivalent with respect to the acid value which match | combined the carboxyl group and ring-opened acid anhydride group which are contained in (A) polyamidoimide resin, The claim 1 or 2 The heat resistant resin composition according to any one of the above.   The water content of the component (C) is 30 to 80% by weight based on the total amount of the component (A), the component (B) and the component (C). Resin composition.   The coating material which uses the heat resistant resin composition in any one of Claims 1-4 as a coating-film component.   The base material which apply | coated and hardened the heat resistant resin composition in any one of Claims 1-5.