JPS646222B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a water-dilutable alkyd resin suitable as a paint resin containing sorbic acid and maleic anhydride as essential components. A method for producing polyester resin using an addition reaction product of sorbic acid and maleic anhydride or sorbic acid and maleic anhydride is described in Japanese Patent Publication No. 46-25866,
It is known from Japanese Patent Publication No. 49-2998. However, when using an addition reaction product of sorbic acid and maleic anhydride, that is, methylcyclohexane tribasic carboxylic acid (hereinafter abbreviated as MHTA), polyester resin is produced by mixing and heating anhydrous MHTA and a polyhydric alcohol. In the process, and in the process of water-solubilizing the polyester resin with a basic substance, there is a problem that in some cases, gel-like particles called microgels or cloudiness are generated.
In addition, in the method of producing polyester resin by simultaneously reacting sorbic acid and maleic anhydride or maleic acid with a polyhydric alcohol to solve these drawbacks, powdered dicarboxylic acids such as isophthalic acid and terephthalic acid are unreacted. It has the disadvantage that it tends to remain in a powder state, and as the reaction progresses, it becomes gelled, impairing water dilutability. However, the present inventors conducted extensive studies to solve these problems and found that (A) oil or fatty acid, (B) polyol, and (C) dicarboxylic acid were combined with an acid value of 80 or less (KOHmg/g). ) After producing the alkyd resin precursor of (D), in the presence of a solvent that is inert to the hydroxyl and carboxyl groups and dissolves sorbic acid, only by adding and reacting (D) sorbic acid and maleic anhydride, When the obtained resin is used as a coating resin, the present invention has been completed by obtaining an excellent effect of further improving the hardness, flexibility, rust prevention, water resistance, etc. of the coating film. The alkyd resin precursor in the present invention is (A)
It is obtained by esterifying oil, fatty acid, (B) polyol, and (C) dicarboxylic acid. First (A)
When using oil as an oil, the weight ratio of oil is 0.6 or less, polyol is 0.2 to 0.5, and dicarboxylic acid is 0.2 to 0.5.
Using Resurge etc. as a catalyst at a ratio of 0.5,
It is necessary to carry out the transesterification reaction at a temperature of 240 to 260°C for about 2 hours. Then, if necessary, use an esterification catalyst such as zinc acetate and heat at 190 to 260°C for about 2 to 6 hours to react until the acid value reaches 80 or less (KOHmg/g), preferably in the range of 5 to 40. . If the acid value exceeds 80, the dicarboxylic acid remains in solid form,
This adversely affects the physical properties of the coating film. When using fatty acids as (A), the weight ratio of fatty acids is 0.6 or less,
0.2-0.5 for polyol, 0.2-0.5 for dicarboxylic acid
The reaction is carried out at a temperature of 190 to 260°C for about 2 to 6 hours, using an esterification catalyst such as zinc acetate if necessary. The subsequent reactions are carried out in the same manner as described above. When using isophthalic acid as the dicarboxylic acid, it is important to keep the acid value at 35 or less, and when using terephthalic acid, it is important to keep the acid value at 15 or less in order to eliminate unreacted substances. Next, when obtaining an alkyd resin from an alkyd resin precursor, in the step of manufacturing the alkyd resin precursor described above, sorbic acid that is inert to hydroxyl groups and carboxyl groups is added at a temperature of 60 to 140°C. Solvents that dissolve, specifically dioxane,
Dimethyl sulfoxide, acetone, etc. are added in a proportion of 0.1 to 10% by weight, preferably 0.5 to 5% by weight, based on the alkyd resin precursor. Then, add sorbic acid and maleic anhydride in an equimolar ratio of 5 to 50% by weight of the total amount of ingredients, preferably
Add 10 to 30% by weight and gradually raise the temperature while distilling off the added solvent at approximately 150 to 180 °C to reach an acid value of 30 to 70.
(KOHmg/g) of alkyd resin is obtained. The sorbic acid was not observed to adhere unreacted to the upper part of the reaction vessel due to the reflux of the added solvent. In the present invention, (A) oils and fatty acids include linseed oil, soybean oil, castor oil, coconut oil, tall oil, cottonseed oil, tung oil, bran oil, fatty acids of the above oils, stearic acid, eleostearic acid, oleic acid, Examples include linoleic acid, ricinoleic acid, linoleic acid, lauric acid, myristic acid, capric acid, and caprylic acid, and one or more of these may be used in combination. The polyol (B) is a known polyol having a divalent or higher hydroxyl group. Specifically, ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, butylene glycol, hexamethylene glycol, neopentyl glycol, cyclohexanedimethanol, hydrogenated bisphenol A, glycerin, diglycerin, trimethylol ethane,
Examples include trimethylolpropane, 1,2,6-hexanetriol, pentaerythritol, sorbitol, dipentaerythritol, and one or more of these may be used in combination. (C) Dicarboxylic acids include phthalic acid, isophthalic acid, terephthalic acid, succinic acid, glutaric acid, adipic acid, suberic acid, sebacic acid, itaconic acid, maleic acid, fumaric acid, dimethylolpropionic acid, etc. One or more of these may be used in combination. The alkyd resin in the present invention is a viscous liquid or solid, and is soluble in alcohols, ketones, and mixtures of these with aliphatic or aromatic hydrocarbons. And/or after dissolving or dispersing in water etc., it is neutralized with a basic compound to obtain a water diluted alkyd resin. Specifically, alkyd resin is dissolved or dispersed in esters such as alcohols, ketones, glycols, and cellosolve acetate, and/or water, and the pH is adjusted to 6 to 10, preferably 6 to 8, using a volatile basic compound. adjust. Examples of the basic compounds include alkylamines such as ammonia, methylamine, ethylamine, diethylamine, triethylamine, butylamine, alkanolamines such as monoethanolamine, diethanolamine, triethanolamine, propanolamine, and aminomethylpropanol, morpholine, pyridine, Examples include piperidine and the like, and are appropriately selected depending on reactivity and volatilization temperature. The water-diluted alkyd resin can be modified by mixing an amino resin such as a melamine-formaldehyde resin, a guanamine-formaldehyde resin, or a urea-formaldehyde resin, as well as a phenol resin, etc., to make it more effective than the alkyd resin alone. Its use is preferred because it improves coating film hardness, low-temperature curability, etc. Other additives such as leveling agents, antifoaming agents, dispersants, anti-sagging agents, thickeners, etc., and pigments such as calcium carbonate, carbon black, titanium oxide, etc. may be added as appropriate depending on the intended use. When the water-dilutable alkyd resin of the present invention is used as a paint resin, it has excellent hardness, flexibility, rust prevention, water resistance, etc., so it can be used in metal containers, vehicles, office equipment, and home appliances. It is suitable as a paint vehicle for metal products such as metal plates and metal plates. Next, the present invention will be specifically explained with reference to Examples. In addition, "parts" in the examples represent "parts by weight" unless otherwise specified. Example 1 132 parts of soybean oil, 114 parts of trimethylolpropane, and 1 part of litharge were charged into a 1-volume flask equipped with a stirrer, a thermometer, a nitrogen blowing tube, and a water-cooled condenser, and a transesterification reaction was carried out at 240°C for 2 hours. Ta.
After lowering the internal temperature to 150°C, 133 parts of isophthalic acid was added and gradually heated. After reacting at 200°C for 4 hours, a clear resin with an acid value of 20 (KOHmg/g) was obtained. Next, after cooling to 80°C, 8 parts of dioquinic acid, 22 parts of sorbic acid, and 20 parts of maleic anhydride were added, and the temperature was raised to 170°C over 2 hours while distilling off dioxane, and then at this temperature for 2 hours. React, acid value 60
(KOHmg/g) of alkyd resin was obtained. No sublimate of sorbic acid was observed in the upper part of the flask after addition of sorbic acid. Butyl cellosolve was added to this alkyd resin to form a 70% by weight solution. 7 parts of triethylamine to 100 parts of the resin solution,
Sumimaru M50W (melamine-formaldehyde resin manufactured by Sumitomo Chemical) 22 parts, carbon black
After adding 4.6 parts of MA100 (manufactured by Mitsubishi Kasei) and thoroughly kneading to disperse the pigment, 150 parts of water was added to obtain a No. 4 water-based black paint with a Ford Cup viscosity of 30 seconds. The paint was applied to a polished mild steel plate using air spray so that the dry film thickness was 20 to 30μ, and then
Baked for 20 minutes at ℃. The physical properties of the resulting coating film were measured and are listed in Table 1. Control Example 1 An alkyd resin was produced in the same manner as in Example 1 except that dioxane was not added. During the heating process after adding sorbic acid and maleic anhydride, a large amount of sorbic acid sublimated from around 110°C and adhered to the upper wall of the flask. Continue to raise the temperature and react at 170℃ for 2 hours until the acid value reaches 60.
(KOHmg/g) of alkyd resin was obtained. This alkyd resin was found to be contaminated with sorbic acid that had adhered to the upper wall of the flask. Thereafter, a coating was prepared in the same manner as in Example 1, and the physical properties of the coating film are listed in Table 1. Control Example 2 An alkyd resin was obtained in the same manner as in Example 1 except that benzene was used instead of dioxane. The alkyd resin was also found to be contaminated with sorbic acid. A paint was prepared in the same manner as in Example 1, and the physical properties of the paint film are listed in Table 1. Control Example 3 After reacting and transesterifying soybean oil and trimethylolpropane in Example 1, isophthalic acid, maleic anhydride, and sorbic acid were added to Example 1.
The reaction was carried out in batches at the same rate. During the heating process, sorbic acid sublimed from around 110°C and adhered to the upper wall of the flask, but from around 200°C it was mixed into the reaction product by the water produced by the esterification reaction. In addition, this reactant has an acid value of 60 (KOHmg/g)
At the stage , the mixture was in the form of a slurry with residual isophthalic acid, so when the reaction was further carried out, it turned into a gel at an acid value of 35 while remaining in the slurry state. (Note) Paint film physical property measurement method 1 Adhesion: Make gong-like cuts in the paint film at 1 mm intervals, apply cellophane tape on top of it, then peel it off, and measure the number of goblin marks that remain after peeling off.
Expressed in 100 hits. 2 Erichsen: Diameter 1 by Erichsen tester
The longest extrusion distance (mm) when an inch punch is extruded from the surface of the paint film to cause scratches on the paint film surface. 3 Dupont impact: By Dupont impact tester
Drop a 500g weight onto the R1/2 inch firing core, and the maximum drop height (cm) without damaging the paint surface due to the firing core 4 40℃ water resistance: Paint film after 48 hours immersion in 40℃ warm water Observation of the condition. 5. Salt spray resistance: Attach a cross cut to the painted surface, spray 5% salt water onto the paint film, apply cellophane tape to the cross cut part once every 24 hours, and then remove it. Peeling width (mm)

【table】

【table】

Claims (1)

[Claims] 1. (A) Oil or fatty acid (B) Polyol (C) Dicarboxylic acid (D) When producing a water-dilutable alkyd resin consisting of sorbic acid and maleic anhydride, (A) and (B) and (C) with an acid value of 80 or less (KOHmg/g)
A method for producing a water-dilutable alkyd resin, which comprises producing an alkyd resin precursor, and then reacting the hydroxyl group and carboxyl group with (D) in the presence of an inert solvent that dissolves sorbic acid. .