Patent Application
20080038545
Hereinafter the present invention is explained still more specifically, referring to working Examples, in which “part” and “%” are “mass part” and “mass %”.
A reaction apparatus equipped with a heater, stirrer, nitrogen inlet tube and a separator was charged with 550 parts of hexahydrophthalic anhydride, 160 parts of adipic acid, 220 parts of trimethylolpropane, 170 parts of neopentyl glycol and 350 parts of 2-butyl-2-ethyl-1,3-propanediol. Heating was started under dry nitrogen and the temperature was gradually raised to 230° C. to carry out an esterification reaction.
While maintaining the temperature of 230° C., the esterification was continued until the acid value dropped to not higher than 1 mgKOH/g. The esterification product was cooled to 170° C., to which 160 parts of trimellitic anhydride, and then 380 parts of ethylene glycol monobutyl ether, were added to provide a carboxyl-containing polyester resin solution having a solid content of 80%. The carboxyl-containing polyester resin had an acid value of 60 mgKOH/g, hydroxyl value of 90 mgKOH/g and number-average molecular weight of 1,500.
A flask equipped with a stirrer, thermometer, nitrogen inlet tube and a reflux condenser was charged with 290 parts of propylene glycol monomethyl ether and kept at 120° C. Into the flask a mixture of the following components was dropped over 3 hours, and then 3 parts of azobisdimethylvaleronitrile was added, to be reacted at a constant temperature of 120° C. for another hour. Thus a carboxyl-containing acrylic resin solution having a solid resin content of 65% was obtained. The carboxyl-containing acrylic resin had an acid value of 78 mgKOH/g, hydroxyl value of 145 mgKOH/g and weight-average molecular weight of 16,000.
A flask equipped with a stirrer, thermometer, nitrogen inlet tube and a reflux condenser was charged with 500 parts of jER828EL (tradename, Japan Epoxy Resin Co., an epoxy resin having an epoxy equivalent of 190 and molecular weight of 350) and to which 200 parts of bisphenol A and 0.1 part of dimethylbenzylamine were added, followed by their reaction at 130° C. until the epoxy equivalent increased to 750. Then 135 parts of dimethylolbutyric acid was added, and the reaction was continued at 130° C. for further 4 hours. Successively adding 77 parts of trimellitic anhydride and then 228 parts of ethylene glycol monobutyl ether, a carboxyl-containing epoxy resin solution having a solid content of 80% was obtained. This carboxyl-containing epoxy resin had an acid value of 78 mgKOH/g, hydroxyl value of 140 mgKOH/g and number-average molecular weight of about 1800.
To 222 parts of isophorone diisocyanate, 44 parts of methyl isobutyl ketone was added, and the temperature was raised to 70° C. Thereafter 174 parts of methyl ethyl ketoxime was dropped into the reaction system over 2 hours. While maintaining this temperature, the system was sampled with time until absence of unreacted isocyanate was confirmed by infrared absorption spectroanalysis. Thus hardener No. 1 of blocked polyisocyanate compound having a solid content of 90% was obtained.
To 87.5 parts (solid content, 70 parts) of the carboxyl-containing polyester resin having a solid content of 80% as obtained in the above Production Example 1, 33.3 parts (solid content, 30 parts) of the hardener No. 1, 3 parts (for neutralization of 0.4 equivalent) of triethylamine and 188.7 parts of deionized water were added to form an aqueous dispersion, from which emulsion No. 1 having a solid content of 32% was obtained.
Emulsion Nos. 2-4 each having the blended composition as shown in Table 1 were prepared by the operations similar to Production Example 5.
A conventional acrylic resin reaction tank equipped with a stirrer, thermometer and reflux condenser was charged with 37 parts of ethylene glycol monobutyl ether, which was heated under stirring and maintained at 110° C.
Into the reaction tank a mixture of the following components was dropped over a period of 3 hours, followed by 30 minutes aging at 110° C. Then an additional mixed catalyst solution formed of 20 parts of ethylene glycol monobutyl ether and 0.5 part of azobisisobutyronitrile was dropped over an hour, followed by an hour's aging at 110° C. Cooling the reaction product, an acrylic resin solution for dispersing pigment, having a solid content of 55% was obtained.
(note 4)NF BISOMER S20W: tradename, Dai-ichi Kogyo Seiyaku Co., Ltd. a 50% aqueous dilution of methoxypolyethylene glycol monomethacrylate, molelcular weight: about 2,080.
The acrylic resin solution for dispersing pigment, having a solid content of 55% as obtained in Production Example 9, 6.3 parts (solid content: 5 parts); JR-600E(note 5), 14 parts; CARBON MA-7(note 6), 0.3 part; HYDRITE PXN(note 7), 9.7 parts; dioctyltin oxide, 1 part; and deionized water, 23.2 parts were dispersed in a ball mill for 20 hours, to provide a pigment-dispersed paste No. 1 having a solid content of 55%.
Pigment-dispersed paste No. 2 was prepared by the operations similar to Production Example 10, except that the components as identified in the following Table 2 were used.
Emulsion No. 1, 219 parts (solid content: 70 parts), 55% pigment-dispersed paste No. 1 as obtained in Production Example 10, 54.5 parts (solid content: 30 parts) and deionized water, 726.5 parts were mixed to form a bath having a solid content of 10%, and to which 1.3 parts of ammonium fluorozirconate was added to provide film-forming agent No. 1.
Film-forming agent Nos. 2-15 were prepared in the manner similar to Example 13, except that the blends as shown in the following Tables 3 and 4 were used.
A bath of film-forming agent No. 1 was adjusted to 28° C., and into which cold-rolled sheet steel (70 mm×150 mm×0.8 mm) which was the object to be coated and served as the cathode was immersed (interpolar distance: 15 cm). The first stage coating was carried out by applying electricity at 5 V for 60 seconds.
Continuously then the second stage coating was carried out by applying electricity at 260 V for 120 seconds, letting the cold rolled sheet steel (70 mm×150 mm×0.8 mm) as the anode (interpolar distance: 15 cm). Thus formed film was baked at 170° C. for 20 minutes with an electric dryer to provide a test panel No. 1.
The current density in the first stage electrification was 0.2 mA/cm2.
Test panel Nos. 2-14 were prepared in the manner similar to Example 1, except that the film-forming agent and electrification conditions as shown in Tables 5 and 6 were used.
Test panel Nos. 15-28 were prepared in the manner similar to Example 1, except that the film-forming agent and electrification conditions as shown in Tables 7 and 8 were used.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2006-215644 | Aug 2006 | JP | national |
