POLYAMIDEIMIDE RESIN COMPOSITION AND FLUORINE-CONTAINING COATING MATERIAL

Abstract

A polyamideimide resin composition containing a polyamideimide resin (A), 4-morpholine carbaldehyde (B), water (C), and a basic compound (D), wherein the change in viscosity of the composition from before storage to after storage at 60° C. for 7 days is within −30%.

Claims

1-7. (canceled)

8. A method for producing a polyamideimide resin composition which contains a polyamideimide resin (A), 4-morpholine carbaldehyde (B), water (C), and a basic compound (D), wherein a change in viscosity of the composition from before storage to after storage at 60° C. for 7 days is within −30%, comprising: a polymerization step of reacting a diisocyanate compound and a tribasic acid anhydride and/or tribasic acid halide in an organic solvent containing 4-morpholine carbaldehyde (B) to form a reaction solution containing the polyamideimide resin (A); a step of adding the basic compound (D) to the reaction solution; and a step of adding water (C) into the reaction solution containing the basic compound (D), wherein the polymerization step is performed by a two-stage heating process comprising a first heating at 70 to 100° C. and a second heating at 110 to 140° C.

9. The method for producing the polyamideimide resin composition according to claim 8, wherein a number average molecular weight of the polyamideimide resin (A) is within a range from 5,000 to 50,000.

10. The method for producing the polyamideimide resin composition according to claim 8, wherein an acid value of the polyamideimide resin (A), composed of a combination of carboxyl groups and other carboxyl groups formed as a result of ring-opening of acid anhydride groups, is within a range from 10 to 80 mgKOH/g.

11. The method for producing the polyamideimide resin composition according to claim 8, wherein an amount of the water (C) is at least 10% by mass relative to a total mass of the polyamideimide resin composition.

12. The method for producing the polyamideimide resin composition according to claim 8, wherein a number average molecular weight of the polyamideimide resin (A) is within a range from 10,000 to 20,000.

13. The method for producing the polyamideimide resin composition according to claim 8, further containing a step of blocking terminal isocyanate groups of the polyamideimide resin with a blocking agent.

14. The method for producing the polyamideimide resin composition according to claim 8, wherein the first heating is performed for 2 to 4 hours, and the second heating is performed for 3 to 5 hours.

Description

EXAMPLES

[0095] A variety of examples are described below, but the preferred embodiments of the present invention are not limited to these examples, and of course also incorporate many embodiments other than these examples based on the scope of the present invention.

[0096] The number average molecular weight and the acid value of the various polyamideimide resins were measured under the following conditions.

Number Average Molecular Weight

[0097] GPC apparatus: HLC-8320GPC manufactured by Tosoh Corporation

[0098] Detector: RI detector manufactured by Tosoh Corporation

[0099] Wavelength: 270 nm

[0100] Data processing unit: ATT 8

[0101] Columns: Gelpack GL-S300MDT-5×2

[0102] Column size: 8 mmø×300 mm

[0103] Column temperature: 40° C.

[0104] Solvent: DMF/THF=1./1 (liter)+0.06 M phosphoric acid+0.06 M lithium bromide

[0105] Sample concentration: 5 mg/mL

[0106] Injection volume: 5 μL

[0107] Pressure: 49 kgf/cm.sup.2 (4.8×10.sup.6 Pa)

[0108] Flow rate: 1.0 mL/min

Acid Value

[0109] First, 0.5 g of the polyamideimide resin composition was sampled, 0.15 g of 1,4-diazabicyclo[2.2.2]octane was added to the sample, about 60 g of N-methyl-2-pyrrolidone and about 1 mL of ion-exchanged water were then added, and the resulting mixture was stirred until the polyamideimide resin dissolved completely. This solution was then titrated against a 0.05 mol/L ethanolic potassium hydroxide solution using a potentiometric titrator to obtain the acid value for the polyamideimide resin, representing the combination of carboxyl groups and those carboxyl groups formed as a result of ring-opening of acid anhydride groups within the polyamideimide resin.

Example 1

[0110] A flask fitted with a thermometer, a stirrer and a condenser was charged with 309.5 g of trimellitic anhydride, 403.2 g of 4,4′-diphenylmethane diisocyanate and 712.7 g of 4-morpholine carbaldehyde, and the resulting mixture was stirred under a stream of dry nitrogen while the temperature was gradually raised to 90° C. over a period of one hour. Following heating at this temperature for three hours, the temperature was gradually raised to 130° C. while particular care was taken over the rapid foaming of carbon dioxide gas that was generated by the reaction, and after continued heating at 130° C. for three hours from the start of the temperature raising process, the reaction was halted, thus obtaining a polyamideimide resin solution.

[0111] The non-volatile fraction (200° C., 2 hours) of this polyamideimide resin solution was 48% by mass. Further, the number average molecular weight of the polyamideimide resin was 15,000, and the acid value, composed of a combination of carboxyl groups and other carboxyl groups formed as a result of ring-opening of acid anhydride groups, was 45 mgKOH/g.

[0112] Subsequently, 1,200 g of the thus obtained polyamideimide resin solution was placed in a flask fitted with a thermometer, a stirrer and a condenser, and the solution was stirred under a stream of dry nitrogen while the temperature was gradually raised to 70° C. When the temperature reached 70° C., 205.9 g (5 equivalents) of N,N-dimethylethanolamine was added, and following thorough stirring with the temperature maintained at 70° C., ion-exchanged water was added gradually to the flask under constant stirring. The ion-exchanged water was added until a final total of 624.0 g of water (water ratio to the all solvent: 50% by mass) had been added, thus obtaining a transparent and uniform polyamideimide resin composition (aqueous heat-resistant resin composition).

Example 2

[0113] A flask fitted with a thermometer, a stirrer and a condenser was charged with 200.8 g of trimellitic anhydride, 262.6 g of 4,4′-diphenylmethane diisocyanate and 501.9 g of 4-morpholine carbaldehyde, and the resulting mixture was stirred under a stream of dry nitrogen while the temperature was gradually raised to 80° C. over a period of one hour. Following heating at this temperature for 4 hours, the temperature was gradually raised to 120° C. while particular care was taken over the rapid foaming of carbon dioxide gas that was generated by the reaction, and after continued heating at 120° C. for 4 hours from the start of the temperature raising process, the reaction was halted, thus obtaining a polyamideimide resin solution.

[0114] The non-volatile fraction (200° C., 2 hours) of this polyamideimide resin solution was 45©% by mass. Further, the number average molecular weight of the polyamideimide resin was 18,000, and the acid value, composed of a combination of carboxyl groups and other carboxyl groups formed as a result of ring-opening of acid anhydride groups, was 40 mgKOH/g.

[0115] Subsequently, 620 g of the thus obtained polyamideimide resin solution was placed in a flask fitted with a thermometer, a stirrer and a condenser, and the solution was stirred under a stream of dry nitrogen while the temperature was gradually raised to 80° C. When the temperature reached 80° C., 97.5 g (5 equivalents) of N,N-dimethylethanolamine was added, and following thorough stirring with the temperature maintained at 80° C., ion-exchanged water was added gradually to the flask under constant stirring. The ion-exchanged water was added until a final total of 279.0 g of water (water ratio of the all solvent: 45% by mass) had been added, thus obtaining a transparent and uniform polyamideimide resin composition (aqueous heat-resistant resin composition).

Example 3

[0116] A flask fitted with a thermometer, a stirrer and a condenser was charged with 791.2 g of trimellitic anhydride, 463.8 g of 4,4′-diphenylmethane diisocyanate, 598.6 g of 3,3′-dimethoxybiphenyl-4,4′-diisocyanate and 2,265.4 g of 4-morpholine carbaldehyde, and the resulting mixture was stirred under a stream of dry nitrogen while the temperature was gradually raised to 100° C. over a period of two hours. Following heating at this temperature for two hours, the temperature was gradually raised to 130° C. while particular care was taken over the rapid foaming of carbon dioxide gas that was generated by the reaction, and after continued heating at 130° C. for 5 hours from the start of the temperature raising process, the reaction was halted, thus obtaining a polyamideimide resin solution.

[0117] The non-volatile fraction (200° C., 2 hours) of this polyamideimide resin solution was 42% by mass. Further, the number average molecular weight of the polyamideimide resin was 15,000, and the acid value, composed of a combination of carboxyl groups and other carboxyl groups formed as a result of ring-opening of acid anhydride groups, was 45 mgKOH/g.

[0118] Subsequently, 3,200 g of the thus obtained polyamideimide resin solution was placed in a flask fitted with a thermometer, a stirrer and a condenser, and the solution was stirred under a stream of thy nitrogen while the temperature was gradually raised to 70° C. When the temperature reached 70° C., 432.4 g (4,5 equivalents) of N,N-dimethylethanolamine was added, and following thorough stirring with the temperature maintained at 70° C., ion-exchanged water was added gradually to the flask under constant stirring. The ion-exchanged water was added until a final total of 1,237.3 g of water (water ratio to the all solvent: 40% by mass) had been added, thus obtaining a transparent and uniform polyamideimide resin composition (aqueous heat-resistant resin composition).

Comparative Example 1

[0119] A flask fitted with a thermometer, a stirrer and a condenser was charged with 512.6 g of trimellitic anhydride, 667.7 g of 4,4′-diphenylimethane diisocyanate and 1,180.3 g of 4-morpholine carbaldehyde, and the resulting mixture was stirred under a stream of dry nitrogen while the temperature was gradually raised to 110° C. over a period of one hour. Following heating at this temperature for one hour, the temperature was gradually raised to 140° C. while particular care was taken over the rapid foaming of carbon dioxide gas that was generated by the reaction, and after continued heating at 140° C. for three hours from the start of the temperature raising process, the reaction was halted, thus obtaining a polyamideimide resin solution.

[0120] The non-volatile fraction (200° C., 2 hours) of this polyamideimide resin solution was 48% by mass. Further, the number average molecular weight of the polyamideimide resin was 9,000, and the acid value, composed of a combination of carboxyl groups and other carboxyl groups formed as a result of ring-opening of acid anhydride groups, was 50 mgKOH/g.

[0121] Subsequently, 1,800 g of this polyamideimide resin solution was placed in a flask fitted with a thermometer, a stirrer and a condenser, and the solution was stirred under a stream of dry nitrogen while the temperature was gradually raised to 60° C. When the temperature reached 60° C., 274.6 g (4 equivalents) of N,N-dimethylethanolamine was added, and following thorough stirring with the temperature maintained at 60° C., ion-exchanged water was added gradually to the flask under constant stirring. The ion-exchanged water was added until a final total of 936.0 g of water (water ratio to the all solvent: 50% by mass) had been added, thus obtaining a transparent and uniform polyamideimide resin composition (aqueous heat-resistant resin composition).

Change in Viscosity (%)

[0122] For each of the polyamideimide resin compositions (varnishes) obtained in the above examples and comparative example, the procedure described below was used to calculate the change in viscosity (%) of the composition from before storage to after storage at 60° C. for 7 days.

[0123] First, the viscosity of the polyamideimide resin composition (varnish) was measured before storage. Subsequently, a fixed amount of the resin composition (varnish) was placed in a sealed container, the sealed container was stored for 7 days inside a dryer set to a temperature of 60° C., and the viscosity of the composition was then remeasured. Using these measure values, the change in viscosity (%) was calculated using (formula 1) shown below.

Change in viscosity (%)=(V2−V1)/V1×100   (Formula 1)

[0124] In formula 1, V1 represents the viscosity measured before storage. V2 represents the viscosity measured after storage for 7 days at 60° C.

[0125] The viscosity measurements were performed in accordance with JIS C 2103, using a B-type viscometer, under conditions including a temperature of 25° C., a No. 3 rotor, and a rotational rate of 12 rpm.

Evaluations

Varnish External Appearance

[0126] Each of the polyamideimide resin compositions (varnishes) obtained in the above examples and comparative example was stored in a sealed container in an environment at 60° C., and the external appearance of the varnish was inspected visually after 7 days.

Adhesion Reduction

[0127] Each of the polyamideimide resin compositions (test coating materials) obtained in the above examples and comparative example was applied to an aluminum substrate (1×50×150 mm, manufactured by Paltec Test Panels Co., Ltd.). An adhesion test was then performed in accordance with the procedure described below.

[0128] Specifically, each of the above substrates to which a test coating material had been applied was subjected to preliminary drying at 80° C. for 10 minutes, and was then baked at 400° C. for 10 minutes, thus obtaining a coating film having an average film thickness of 10 μm across 5 locations. Cuts were then formed in this coating film to generate 1 mm squares in a 10×10 grid pattern, portions of an adhesive tape (manufactured by Nichiban Co., Ltd.) were adhered to, and then peeled from, the surface 5 times, and the number of remaining squares was counted.

[0129] The above adhesion test was performed using a sample of the resin composition before storage under heat, and also using a sample of the resin composition that had been stored at 60° C. for 7 days, and the reduction in adhesion was then calculated using (formula 2) shown below.

Reduction in adhesion (%)=(A2−A1)/A1×100   (Formula 2)

[0130] In formula 2, A1 represents the adhesion evaluation result using the resin composition before storage. A2 represents the adhesion evaluation result using the resin composition after storage at 60° C. for 7 days.

[0131] The various evaluation results are shown in Table 1.

TABLE-US-00001 TABLE 1 Comparative Item Example 1 Example 2 Example 3 Example 1 Polyamideimide resin 4-morpholine carbaldehyde polymerization solvent Water ratio to the all solvent 50 40 40  50 (% by mass) Change (%) in viscosity from before −20 −25 −28  −50 storage to after storage at 60° C. for 7 days External appearance after storage at transparent transparent transparent turbid 60° C. for 7 days Change (%) in adhesion from before 0 0 −4 −70 storage to after storage at 60° C. for 7 days

[0132] As shown in Table 1, the polyamideimide resin compositions obtained in the examples each exhibited a change in viscosity within −30%, and exhibited either no reduction in adhesion after storage at 60° C. for 7 days, or extremely little reduction. In contrast, the resin composition obtained in Comparative Example 1 exhibited a change in viscosity that exceeded −30%, and the adhesion after storage at 60° C. for 7 days displayed a dramatic reduction. Further, the external appearance of the polyamideimide resin compositions of the examples after storage at 60° C. for 7 days was transparent in each case. In contrast, the external appearance of the polyamideimide resin composition of Comparative Example 1 after storage at 60° C. for 7 days showed turbidity. Based on these results, it was evident that for resin compositions using a solvent other than NMP, by ensuring that the reduction in viscosity of the composition from before storage to after storage at 60° C. for 7 days is within a prescribed range, excellent storage stability can be obtained, and any deterioration in properties can be suppressed.