JPS623858B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention provides a method for producing a new water-soluble alkyd resin using a 1,2-epoxyalkane that provides a resin solution with excellent hydrolysis resistance and a cured product with very excellent weather resistance and coating properties. It is related to. Water-soluble alkyd resins are usually obtained by water-solubilizing oil-soluble resins, and are excellent in combination with phthalic anhydride, 1,2-epoxyalkanes, dihydric or higher alcohols, and unsaturated fatty acids. A cured product having coating film properties is obtained. However, such water-soluble alkyd resins have the drawback of being easily hydrolyzed by solvents and having poor storage stability. However, the present inventors used isophthalic acid or terephthalic acid or their diesters in place of phthalic anhydride, which is the cause of such drawbacks, and reacted 1,2-epoxyalkanes with dihydric or higher alcohols. This improves the hydrolysis resistance, which is the drawback mentioned above, and makes it stable even during long-term storage.Furthermore, weather resistance such as gloss retention is further improved, and the film has very excellent physical properties. This discovery led to the present invention. Water-soluble alkyd resins that use 1,2-epoxyalkane include those that use 1,2-octene oxide (Laporte, technical information), but this is a combination of dipentaerythritol and phthalic anhydride. Next, 1,2-octene oxide is ring-opened and esterified,
The baked coating film is hard and brittle, and the resin lacks compatibility, so that it has not reached a state that is fully satisfactory as a paint resin. However, the present invention uses isophthalic acid, adipic acid and 1.
The present invention provides a method for producing a resin from 2-epoxyalkane or the like using a reaction method that also uses a dehydration esterification reaction different from the above reaction method. The present invention comprises: (1) one or a mixture of two or more 1,2-epoxyalkanes having 6 to 28 carbon atoms, isophthalic acid or terephthalic acid, or esters thereof;
A polyester having an acid value of 5 or less, a hydroxyl value of 40 to 200, and an average molecular weight of 600 to 2,500 is produced by reacting with a saturated aliphatic dicarboxylic acid having 3 or more carbon atoms and a dihydric or higher alcohol; 80 by reacting the hydroxyl group of the polyester with an aromatic carboxylic acid anhydride of divalent or higher valence, and (3) further neutralizing with a base to make the alkyd water-soluble. This is a method for producing resin. 1/2 having 6 to 28 carbon atoms used in the present invention
- Epoxy alkanes include 1,2-epoxyhexane, 1,2-epoxyheptane, 1,2-epoxyoctane, 1,2-epoxynonane, 1,2-
Epoxydecane, 1,2-epoxyundecane,
1,2-epoxydodecane, 1,2-epoxytetradecane, 1,2-epoxyhexadecane,
1,2-epoxyoctadecane, etc., and has the general formula

It has [Formula]. Here, n is an integer satisfying 3≦n≦25.
When n<3, compatibility with other resins is lacking, and when n>25, the coating film becomes flexible, which is disadvantageous. Although 1,2-epoxyalkanes having any number of carbon atoms within this range can be used, it is preferable to use 1,2-epoxyalkanes having from 10 to 18 carbon atoms in order to obtain particularly good water-soluble alkyd resins. These 1,2-epoxyalkanes are industrially obtained from α by polymerization of ethylene.
- Obtained by epoxidizing olefins with organic peracids such as peracetic acid, perbenzoic acid, or other peroxides such as hydrogen peroxide. These 1,2-epoxyalkanes can be used as a single compound or as a mixture of two or more compounds. As for the acids which are one of the other raw materials of the present invention, isophthalic acid or terephthalic acid or their esters are used as aromatic polybasic acids, and a part of aromatic dicarboxylic acids or these diesters is also used as adipic acid, It can also be replaced with an aliphatic dicarboxylic acid such as maleic acid or its anhydride, an unsaturated fatty acid such as oleic acid, linoleic acid, or linoleic acid, an aromatic tricarboxylic acid such as trimellitic acid or its anhydride, or the like. Ethylene glycol, propylene glycol, diethylene glycol, and neopentyl glycol are used as divalent alcohols, and trihydric alcohols such as glycerin, trimethylolethane, and trimethylolpropane, and pentaerythrite and dihydric alcohols are used as divalent alcohols. There are alcohols with a valence of 4 or more, such as glycerin. The alcohols shown here can be used alone, but it is of course also possible to use a mixture of two or more. The molar ratio of the three raw materials used in the present invention, namely polybasic acid, polyhydric alcohol, and 1,2-epoxyalkane, can be determined by applying the concept usually used to determine the processing method for water-soluble alkyd resins. The molecular weight of the resulting resin is largely controlled by the ratio of the amount of acids used, which are sources of carboxyl groups, to the amounts of alcohols and epoxides, which are sources of hydroxyl groups. Furthermore, as will be described later, it goes without saying that free hydroxyl groups determined by the difference between carboxyl groups and hydroxyl groups are necessary for curing reactions with amino resins and the like. Another factor that determines the molecular weight is the molar ratio of polyhydric alcohols used. In other words, when a large amount of trihydric or tetrahydric or higher polyhydric alcohol is used, the molecular weight of the resulting water-soluble alkyd resin increases, as well as the number of free hydroxyl groups increases, making it difficult to combine with crosslinkable resins such as hexamethoxymethylated melamine resin. The cured coating obtained by baking the coating composition made of the mixture is hard and brittle; on the other hand, when a large amount of dihydric alcohol is used,
The resin has a low molecular weight and also has a small number of free hydroxyl groups, and the cured coating obtained by baking a coating composition made of a combination with the above-mentioned hexamethoxymethylated melamine etc. becomes soft. Further, the amount of 1,2-epoxyalkane used is also a factor that determines the proportion of side chain alkyl groups in the alkyd resin, and controls the properties of the cured coating film. The amount of the epoxy alkane used in the present invention is suitably in the range of 10 to 50% by weight based on the water-soluble alkyd resin finally obtained. Based on the above concept, the resin produced in the present invention can be produced by adjusting the molar ratio of the three raw materials used: polybasic acid such as isophthalic acid or terephthalic acid or their diesters, polyhydric alcohol, and 1,2-epoxyalkane, and the polyhydric acid. Average molecular weight obtained by adjusting the molar ratio of alcohols used
600-2500, preferably 600-1800, hydroxyl value 40-
200, preferably from 120 to 190. However, there is a certain correlation between this average molecular weight and hydroxyl value, and when the average molecular weight is high, the hydroxyl value is low, or it is necessary to reverse each other. Usually, the average molecular weight is 700 to 1200,
The hydroxyl value is 140-190. The reaction consists of a first step and a second step. In the first step, a mixture of acid and polyol is
After gradually adding and reacting 1,2-epoxyalkane while stirring at 100 to 150°C, add 5 to 20% by weight of an azeotropic solvent such as xylene, and heat to 150 to 250°C.
Water is removed from the reaction system while stirring with heating to further advance the esterification reaction to produce a polyester having a hydroxyl group with an acid value of 5 or less. Catalysts that promote the reaction between this 1,2-epoxyalkane and acid include amines (especially tertiary amines), quaternary ammonium salts, phosphine compounds, and boron trifluoride (itself or its complexes with ethers, amines, etc.) etc. in an amount of 0.01 to 5% by weight, preferably 0.1% by weight, based on the 1,2-epoxyalkane.
~1.0% by weight can also be used. In the above reaction, the lower the reaction temperature, the better the color of the resin, and passing an inert gas such as nitrogen into the reaction mixture during the reaction also has a similar effect. In the second step, an acid anhydride such as phthalic anhydride or trimellitic anhydride is added to the polyester having hydroxyl groups obtained in the first step, and the mixture is heated and stirred at 100 to 150°C to remove the carboxyl groups. Obtain an alkyd resin having If this alkyd resin has an acid value of about 25 or more, it can be fully mixed with water by adding bases and neutralized to a pH value between 7.0 and 9.0, or by adding an organic solvent that is completely miscible with water. Can be dissolved in water. Generally, alkyd resins having an acid value of 25 to 80 are preferred. Among the bases used in the present invention, organic amines include alkyl amines such as monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, and butylamines, monoethanolamine, and diethanolamine. , alcohol amines such as triethanolamine, diethylaminoethanol, and dimethylaminopropanol, and cyclic amines such as morpholine and pyridine. Also, ammonia or sodium hydroxide may be used as an inorganic base. Further, organic solvents include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, cyclohexanone, cyclooctanone, cyclododecanone, n-butanol, isobutanol, sec-butanol, tert-butanol, etc. . The water solubilization treatment method involves first dissolving the alkyd resin obtained in the second step in one or more of the above organic solvents that are partially or completely miscible with water, and then adding a base. The viscosity of the solution obtained by diluting the resulting salt solution with water is, of course, most influenced by the molecular weight of the alkyd resin, but also by the type and amount of the organic solvent used. It is fixed. In the water-soluble alkyd resins thus obtained, amino resins are used as hardeners for producing baking enamels. Suitable examples of such amino resins include hydrophilic amino resins etherified with lower aliphatic alcohols having 4 or less carbon atoms, such as methyl etherified melamine resins, methyl etherified urea melamine cocondensation resins, and partially butyl etherified melamine resins. Baking-type amino alkyd paint obtained by blending the above water-soluble alkyd resin and amino resin.
It has been shown that heating to temperatures between 0.degree. The present invention will be explained below with reference to Examples and Reference Examples. In addition, in the following description, parts are parts by weight,
% indicates weight %. Example 1 A mixture of 72.0 parts of isophthalic acid, 34.1 parts of adipic acid, 72.6 parts of neopentyl glycol, and 14.7 parts of trimethylolpropane was added to a four-channel 500 c.c. The mixture was heated and stirred at 140° C. for 1 hour while flowing nitrogen gas into the neck flask. Then, while maintaining the same temperature
AOEX24 (Product name of Daicel Corporation: 1・2-
Mixture of epoxy dodecane and 1,2-epoxytetradecane, epoxy equivalent 208) 58.7 parts, N.N.
- After 0.18 parts of dimethylbenzylamine was added dropwise over 1 hour, the temperature was gradually raised to 230°C over 5 hours. In order to further advance the esterification reaction, the reaction was carried out at 230°C for 2 hours, and 28.9 parts of water was distilled out, yielding a resin with an acid value of 0.94. Then trimellitic anhydride was applied to the above resin.
Add 22.4 parts and heat at 140℃ for 2 hours to change the acid value.
It became 50.3. 20.5 parts of butyl cellosolve for 90 parts of this resin
After adding 20.5 parts of t-butanol and mixing well, 8.0 parts of triethylamine was added and 41.0 parts of water were added to obtain 180 parts of a resin solution. The viscosity of the solution is
480 cps (measured at 28°C) Add hexamethylated melamine (Sumimar M-50W, Sumitomo Chemical) to this resin solution.
Co., Ltd. products) and rutile titanium oxide (Taipeke R-
820 (produced by Ishihara Sangyo Co., Ltd.) at a solid content ratio of 48:12:40 and mixed for 24 hours in a ball mill to obtain a white enamel amino alkyd paint. It was applied to a thin mild steel plate and a tin plate and baked at 40°C for 30 minutes and then at 120°C for 30 minutes to obtain a coating film with a thickness of 30μ. The properties of the coating film are shown in Table 1. Example 2 A mixture of 95.5 parts of isophthalic acid, 25.6 parts of adipic acid, 17.7 parts of neopentyl glycol, and 49.2 parts of trimethylolpropane was added under the same conditions as in Example 1.
118.7 parts of AOEX24 and 0.36 parts of N.N-dimethylbenzylamine were reacted to obtain a resin with an acid value of 0.88.
This resin was then treated with trimellitic anhydride 32.0
When the mixture was heated at 140°C, the acid value became 41.1. Next, butyl cellosolve was added to 90 parts of this resin.
After adding 21.2 parts and 21.2 parts of t-butanol and mixing well, 5.4 parts of triethylamine was added and further 42.2 parts of water were added to obtain 180 parts of an aqueous resin solution. The viscosity of the solution was 3500 ops (measured at 25°C) and the pH was 8.86. A white enamel aminoalkyd paint was prepared using the same formulation as in Example 1, and the properties of the baked coating film are shown in Table 1. Example 3 The same as in Example 1 was added to a mixture of 72.0 parts of isophthalic acid, 34.1 parts of adipic acid, 72.6 parts of neopentyl glycol and 14.7 parts of trimethylolpropane.
AOEX68 (Product name of Daicel Corporation: 1・2-
Mixture of epoxy hexadecane and 1,2-epoxy octadecane Epoxy equivalent weight 218) 64.0 parts, N.
React with 0.18 parts of N-dimethylbenzylamine,
A resin with an acid value of 0.64 was obtained. This resin was then treated with trimellitic anhydride.
When 22.4 parts were added and heated at 140°C, the acid value became 43.3. Next, butyl cellosolve was added to 90 parts of this resin.
Add 20.8 parts of t-butanol, mix well, add 7.0 parts of triethylamine, and add water.
41.5 parts were blended to obtain 180 parts of an aqueous resin solution. The viscosity of the solution was 525 cps (measured at 25°C) and the pH was 8.44. A white enamel aminoalkyd paint was prepared using the same formulation as in Example 1, and the properties of the baked coating film are shown in Table 1. Example 4 AOEX24 was added to a mixture of 110.7 parts of isophthalic acid and 70.7 parts of neopentyl glycol under the same conditions as in Example 1.
90.4 parts and 0.27 parts of N.N-dimethylbenzylamine were reacted to obtain a resin with an acid value of 1.33. This resin was then treated with trimellitic anhydride.
When 22.4 parts were added and heated at 140°C, the acid value became 49.5. Next, 20.5 parts of butyl cellosolve and 20.5 parts of t-butanol were added to 90 parts of this resin, and after mixing well, 8.0 parts of triethylamine was added, and further 41.0 parts of water were added to obtain 180 parts of an aqueous resin solution.
The viscosity of the solution was 914 cs (measured at 25°C) and the pH was 8.81. A white enamel aminoalkyd paint was prepared using the same formulation as in Example 1, and the properties of the baked coating film are shown in Table 1. Example 5 Dimethyl isophthalate 84.2 parts, adipic acid 34.1 parts
58.7 parts of AOEX24 and 0.18 parts of N.N-dimethylbenzylamine were reacted with a mixture of 72.6 parts of neopentyl glycol and 14.7 parts of trimethylolpropane under the same conditions as in Example 1 to obtain a resin with an acid value of 0.67. Next, 22.4 parts of trimellitic anhydride was added to this resin and heated at 140°C, resulting in an acid value of 46.4 parts. Next, butyl cellosolve was added to 90 parts of this resin.
Add 20.6 parts of t-butanol and 20.6 parts of t-butanol, mix well, add 7.5 parts of triethylamine, and add water.
41.2 parts were blended to obtain 180 parts of an aqueous resin solution. The viscosity of the solution was 235 cps (measured at 25°C) and the pH was 9.00. A white enamel aminoalkyd paint was prepared using the same formulation as in Example 1, and the properties of the baked coating film are shown in Table 1. Comparative Example 1 85.2 parts of phthalic anhydride, 25.6 parts of adipic acid, 5.2 parts of neopentyl glycol, and 39.1 parts of glycerin.
of AOEX24 105 under the same conditions as in Example 1.
1 part and 0.32 part of N.N-dimethylbenzylamine were reacted to obtain a resin having an acid value of 0.93. Next, 29.6 parts of phthalic anhydride was added to this resin and heated at 130°C, resulting in an acid value of 43.9. To 90 parts of this resin having an acid value of 43.9, 20.7 parts of butyl cellosolve and 20.7 parts of t-butanol were added, and after thorough mixing, 7.2 parts of triethylamine was added, and further 40.6 parts of water were added to obtain 180 parts of an aqueous resin solution.
The viscosity of the solution was 440 cps (measured at 25°C) and the pH was 7.02. Table 1 shows the storage stability of the resin solution and the properties of a baked coating film prepared from a white enamel aminoalkyd paint using the same formulation as in Example 1. Comparative Example 2 42.9 parts of AOEX24 and N/N-dimethylbenzylamine were added to a mixture of 71.9 parts of phthalic anhydride, 12.5 parts of adipic acid, 17.8 parts of neopentyl glycol, 30.3 parts of glycerin, and 20 parts of soybean oil fatty acid under the same conditions as in Example 1. 0.13 part was reacted to obtain a resin with an acid value of 0.99. Next, 27.5 parts of phthalic anhydride was added to this resin and heated at 130°C, resulting in an acid value of 48.8. To 90 parts of this resin having an acid value of 48.8, 20.5 parts of butyl cellosolve and 20.5 parts of t-butanol were added, and after thorough mixing, 8.0 parts of triethylamine was added, and further 41.0 parts of water were added to obtain 180 parts of an aqueous resin solution.
The viscosity of the solution was 430 cps (measured at 25°C) and the pH was 8.15. Table 1 shows the storage stability of the resin solution and the properties of a baked coating film prepared from a white enamel aminoalkyd paint using the same formulation as in Example 1.

【table】

Claims (1)

[Scope of Claims] 1 (1) One or a mixture of two or more 1,2-epoxy alkanes having 6 to 28 carbon atoms, isophthalic acid or terephthalic acid, or esters thereof, or saturated aliphatic acids having 3 or more carbon atoms. React with dicarboxylic acid and dihydric or higher alcohols to achieve an acid value of 5.
Below, hydroxyl value 40-200, average molecular weight 600-2500
(2) Then, the hydroxyl groups of the polyester are reacted with an aromatic carboxylic acid anhydride having a divalent or higher valence so as to have an acid value of 25 to 80, and (3) the polyester is further neutralized with a base. 1. A method for producing a water-soluble alkyd resin, characterized by making it water-soluble. 2 1,2-Epoxyalkane has 10 or more carbon atoms
18. The method according to claim 1, wherein the 1,2-epoxyalkane is 18. 3. The method according to claim 1 or 2, wherein the alcohol is one or a mixture of two or more selected from the group consisting of neopentyl glycol, trimethylolpropane, and glycerin.