JPH0411592B2 - - Google Patents

Description

[Detailed description of the invention]

In recent years, there has been a strong desire for paints with excellent weather resistance from the perspective of resource conservation, especially in the automobile industry. The appearance of a paint that has a glossy appearance and a coating film that does not fade due to wax even when applied with wax has been awaited, and this has become a goal set in the paint industry. Traditionally, acrylic resins have been used in combination with melamine/formaldehyde resins for automotive top coats, and coconut oil-modified or synthetic fatty acid-modified short oils have been used for solid colors. Alkyd resins have been used in combination with similar melamine resins. However, none of these resins has a high degree of weather resistance, and they are accompanied by fatal defects, especially when used in top coatings for automobiles. However, as a result of intensive research by the present inventors in order to eliminate all of the drawbacks of conventional resins as described above and to obtain a resin that has a high degree of weather resistance and also has excellent gloss and hardenability, We have previously filed an application for a paint resin composition that is a blend of specific alkyd resins as disclosed in Publication No. 36149, but we have further researched it and are applying it specifically to organic pigments for automotive solid colors. alkyd resin for paints with excellent dispersibility, and
The present invention was completed by discovering an alkyd resin paint obtained using such a resin. That is, the present invention mainly provides an alkyd resin paint containing as a main film-forming component an alkyd resin obtained using a polyhydric carboxylic acid component and a polyhydric alcohol component, in which the alkyd resin contains, as the carboxylic acid component, The molar ratio of alicyclic carboxylic acid to aromatic carboxylic acid is 50:50 to 95:5, and the residues based on these two carboxylic acids are 30% based on the resulting alkyl resin. It is obtained by condensing an ester-forming inorganic or organic phosphorus compound so that the amount of the inorganic or organic phosphorus compound is 0.5 to 5% by weight based on the resulting alkyd resin. Moreover, the oil length is 50%.
The present invention provides an alkyd resin coating comprising the following: The present inventors started by obtaining a resin with high gloss retention through outdoor exposure and accelerated weathering tests, as described in the previous Japanese Patent Application Laid-Open No. 57-36149, and further proceeded to: In addition, it has excellent adsorption power to inorganic pigments such as rutile-type titanium oxide, or organic pigments such as quinacridone-based or thren-based red pigments, anthathurone-based orange pigments, or quinophthalone-based yellow pigments. It protects these pigments from UV rays, heat, oxygen, and moisture, which are factors that accelerate the deterioration of paint films.
Moreover, the resin itself must be resistant to the deterioration energy described above, which is a condition for improving the weather resistance of this type of solid color resin. I got the conclusion. Incidentally, although the surface of the above-mentioned titanium oxide is covered with hydroxyl groups, once such pigments come into contact with ultraviolet rays, oxygen, or moisture, which are the above-mentioned deterioration accelerating factors, or are kept in such an atmosphere. This deterioration energy generates radicals, which deteriorate the resin itself, and also has the effect of accelerating this deterioration. Based on the deterioration mechanism of A carboxylic acid having a ring, that is, a molar ratio of alicyclic carboxylic acid and aromatic carboxylic acid is 50:50 to 95:5, preferably 70:
By condensing an organic phosphorus compound in an amount of 0.1 to 5% by weight, preferably 0.25 to 2% by weight, into an alkyd resin obtained by using both carboxylic acids of 30 to 90:10 as essential acid components. It was also revealed that a resin meeting the above-mentioned purpose could be obtained. The amount of condensed inorganic or organic phosphorus compounds is 0.1
If it is less than % by weight, the adsorption power of the resin to the pigment will be weak and the object of the present invention will not be achieved;
On the other hand, if it exceeds 5% by weight, the adsorption force will be too strong and the coating system will become thixotropic, and the resin itself will also be susceptible to hydrolysis, which is not preferred. If the molar ratio of alicyclic carboxylic acid to aromatic carboxylic acid exceeds 50:50 and the amount of alicyclic carboxylic acid becomes too small, sufficient weather resistance cannot be exhibited. If the ratio exceeds the amount of aromatic carboxylic acid and the amount of aromatic carboxylic acid is too small,
Either case is unfavorable because sufficient gloss and sharpness cannot be achieved. The organic phosphorus compound referred to in the present invention refers to all compounds except phosphinic acid, but among them, only the most representative ones are listed below. For example, the general expression or [However, R in both formulas represents a phenyl group and/or a _C1 to _C5 alkyl group. ] A dialkyl phosphate or trialkyl phosphate compound represented by [However, R in the formula is as described above. ] The dialkyl phosphite compounds shown are effective, including trimethyl phosphate, triethyl phosphate, triphenyl phosphate, di-n-butyl phosphate or "Supervecamine P-198" [Dainippon Ink Chemical Co., Ltd.] Made of C ₁ ~ C ₅
Phosphate ester of alcohol]: dimethyl phosphite, diethyl phosphite or aditol
XL-180 (organic phosphorus compound manufactured by Hoechst, West Germany) etc. are effective. Typical examples of the inorganic phosphorus compounds include phosphoric acid, phosphorous acid, phosphorus pentoxide, and tripolyphosphoric acid, but it is much more desirable to use the above-mentioned organic phosphorus compounds from an operational standpoint. As a method for condensing such an inorganic or organic phosphorus compound into a resin, the fatty acid method is
It is best to add the compound from the early stage of the reaction, and in the oil method, it is desirable to add it immediately after the alcohol exchange reaction is completed to perform the esterification reaction, but this does not prevent it from being added in the latter half of the alkyd resin condensation reaction. do not have. Through such a known and commonly used condensation reaction, the phosphoric acid group in the ester-forming inorganic or organic phosphorus compound easily reacts with the hydroxyl group in the resin and is incorporated into the resin in the form of a phosphoric ester bond. However, it goes without saying that such preparation is extremely obvious to those skilled in the art. By the way, the preferred oil length for the resin of the present invention is
50% or less, particularly preferably in the range from 5 to 40%. If it exceeds 50%, not only will the film hardness of the coating material become low, but also the dispersibility of the pigment will become extremely poor, which is not preferable in either case. On the other hand, the molecular weight of the resin of the present invention is also an important factor, and the number average molecular weight referred to in the present invention is calculated by the following formula,
However, organic phosphorus compounds are not included in this calculation. n=W/(K-P)e _A [] [However, W in the formula is the weight of the amount of raw materials minus the amount of dehydration, that is, the weight of the produced resin, and K is the so-called The K value is separately given as total number of moles/equivalent of acid, where P represents the reaction rate and e _A represents the total number of equivalents of acid. ] This formula was developed by Interscience Publishers Division of John Wiley & Sons (International
publishersdivisions of John Wiley and sons)
Published by T.C. Patton (TC
Patton) “Alkyd Resin Technology”
(“Alkyd Resin Technology”), page 110, as formula 18. If the molecular weight calculated in this way is less than 1000, the hardness and chemical resistance of the coating film will be poor, while if it exceeds 6000, wetting to the pigment will be poor and the protective effect of the pigment will be weakened. Moreover, since the molecular weight becomes too high, the spray workability becomes poor, and in the end, the composition lacks practicality, so neither of these is preferable. Here, the alkyd resin used in preparing the coating material of the present invention will be described in detail. First, the alicyclic carboxylic acids that are the main component of the core component include:
Examples include 1,1-cyclohexanedicarboxylic acid, hexahydrophthalic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, and methylhexahydrophthalic acid. Cyclohexane monocarboxylic acids such as butylcyclohexane monocarboxylic acid or hexahydrobenzoic acid, cyclohexane polycarboxylic acids, and even methyl esters thereof can be used similarly. On the other hand, typical aromatic carboxylic acids include (anhydrous) phthalic acid, isophthalic acid, and terephthalic acid, but in addition, benzoic acid, p-tert-butylbenzoic acid, and p- Monocarboxylic acids such as methylbenzoic acid and the like can also be effectively used as molecular weight modifiers, and polycarboxylic acids such as trimellitic anhydride or pyromellitic anhydride can also be used with various acid components as described above. Furthermore, in addition to the acids described above, the alkyd resin used in preparing the coating material of the present invention includes adipic acid, azelaic acid, sebacic acid, tetrahydrophthalic anhydride, tetrachlorophthalic anhydride, and hexyl anhydride. acid, hymic anhydride,
Maleic anhydride, fumaric acid, itaconic acid or methylcyclohexenetricarboxylic anhydride can be used. Next, there are no particular restrictions on the alcohol component to be used with the above acid component, but typical examples include ethylene glycol, propylene glycol, 1,3-butylene glycol, 1,6-hexanediol, diethylene glycol, Examples include dipropylene glycol, neopentyl glycol, triethylene glycol, cyclohexanedimethanol, hydrogenated bisphenol A, glycerin, trimethylolethane, trimethylolpropane, pentaerythritol or dipentaerythritol. In addition, typical oil and fat components include coconut oil, hydrogenated coconut oil, "Carduura E" (glycidyl ester of Versatellite acid manufactured by Siel in the Netherlands), and octylic acid.
Rice bran oil fatty acids, tall oil fatty acids, soybean oil, castor oil or dehydrated castor oil can also be used. The alkyd resin of the present invention is prepared using the various raw materials listed above by either the melt method or the solvent method according to known production methods. The thus obtained alkyd resin paint of the present invention is used particularly for automotive solid colors, and has not only a high degree of weather resistance but also excellent pigment dispersibility, waxing resistance, gloss, and hardening properties. It provides a membrane. Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples. In the following, all parts and percentages are based on weight unless otherwise specified. Example 1 A four-necked flask equipped with a stirrer, a thermometer, a reflux condenser with a dehydration trap, and a nitrogen gas introduction device was charged with 300 parts of coconut oil, 0.15 parts of sodium hydroxide, and 132 parts of trimethylolpropane. After carrying out an alcohol exchange reaction at 250°C for 1 hour, 77 parts of trimethylolpropane, 20 parts of "Supervecamine P-198", 94 parts of pentaerythritol, 351 parts of hexahydrophthalic anhydride, and 44 parts of hexahydrophthalic anhydride were added. of phthalic anhydride, 49 parts of p-tert-butylbenzoic acid and 40 parts of xylene and held at 160 to 180°C for 3 hours, then heated to 180°C.
The temperature was gradually raised to ~220°C over 2 hours, followed by a dehydration reaction at 220°C for 2 hours, and then
Adjust the nonvolatile content to 60% with xylene, and the Gardner viscosity (hereinafter abbreviated as "viscosity") at 25°C is V, the acid value is 7.2, and the hydroxyl value is 75.
A solution of alkyd resin was obtained. The acid value of "Super Betsukamine P-198" used in this example is 430, and for example, this "Super Betsukamine P-198"
-198'' is 17.6, and on the other hand, the acid value of the resin solution after reaction is 7.2 (in terms of solid content,
12.0), it is known that the resin contains a phosphorus compound in a condensed form. The number average molecular weight of this alkyd resin is calculated as follows. First, from the amount charged in this example, the total number of moles is 6.890, and the total number of acid equivalents e _A
Since is 6.769, the K value is 1.0178, and the acid reaction rate P is 0.9684 from the acid value, and furthermore,
By subtracting the dehydrated amount of 47 parts from the total amount of 1.047 parts, the resin yield W becomes 1000 parts, so according to the above calculation formula [], the number average molecular weight n of the resin to be determined is approximately 3000. . = 1000/1.0178-0.9684) x 6.769 = 1000/0.3343 = 2991 Here, the reaction rate P mentioned above is calculated as follows, but first, the acid value of the produced resin is
7.2 (12.0 in terms of solid content), the equivalent of the acid after the reaction is 12.0 x 1000/56100 = 0.2139 from the acid value x milligram equivalent of W/KOH. Therefore, the reaction rate of the acid to be determined is P
is 6.769-0.2139/6.769=0.9684 from acid equivalent before reaction e _A - acid equivalent after reaction/acid equivalent before reaction e _A. The number average molecular weights for each of the following Examples and Comparative Examples can also be determined in the same manner. They are summarized in Table 2. Example 2 400 parts of coconut oil, 0.2 parts of lithium hydroxide, and 123 parts of pentaerythritol were charged and an alcohol exchange reaction was carried out at 230°C for 1 hour. Example 1 except that 275 parts of cyclohexanedicarboxylic acid, 52 parts of benzoic acid, 95 parts of pentaerythritol, 25 parts of neopentyl glycol, and a mixture of 40 parts of xylene and 5 parts of phosphorus pentoxide were charged. Similarly, a solution of an alkyd resin having a viscosity of Z ₂ to _{Z 3} , an oxidation value of 5.4, and a hydroxyl value of 66 was obtained. Example 3 265 parts of "Carduura E", 297 parts of hexahydrophthalic anhydride, 184 parts of isophthalic acid, 123 parts of pentaerythritol, 155 parts of neopentyl glycol, 52 parts of hexahydrobenzoic acid, "Aditol XL-180"'' and 40 parts of xylene, a dehydration condensation reaction was immediately started at 160 to 180°C for 3 hours, and then the same procedure as in Example 1 was carried out to prepare an alkyd with a viscosity of TU, an acid value of 4.8, and a hydroxyl value of 69. A solution of resin was obtained. Example 4 142 parts of coconut oil fatty acid, 130 parts of isophthalic acid,
401 parts of 1,4-cyclohexanedicarboxylic acid,
194 parts of trimethylolpropane, 95 parts of neopentyl glycol, 1,6-hexanediol
A solution of an alkyd resin having a viscosity M, an acid value of 6.0, and a hydroxyl value of 72 was obtained in the same manner as in Example 3 using 168 parts of xylene, 40 parts of xylene, and 40 parts of "Supervecamine P-198". Example 5 The procedure was the same as in Example 2, except that 7.8 parts of an 89% phosphoric acid aqueous solution was used instead of phosphorus pentoxide, and the viscosity was Z ₃ , the oxidation was 5.2, and the hydroxyl value was A solution of an alkyd resin with a value of 65 was obtained. Example 6 112 parts of "Carduura E", 260 parts of trimethylolpropane, 189 parts of 1,6-hexanediol
The reaction was carried out in the same manner as in Example 4, except that 212 parts of isophthalic acid, 295 parts of hexahydrophthalic anhydride, and 10 parts of phosphorous acid were used. % to obtain a solution of an alkyd resin having a viscosity of X, an acid value of 6.6, and a hydroxyl value of 133. Example 7 96 parts of coconut oil fatty acid, 220 parts of trimethylolpropane, 242 parts of neopentyl glycol, 176 parts of isophthalic acid, hexahydrophthalic anhydride
The reaction was carried out in the same manner as in Example 4, except that 221 parts of adipic acid, 155 parts of adipic acid, and 10 parts of di-n-butyl phosphate were used.
The nonvolatile content was adjusted to 60% with "Solbetsuso 100" (aromatic hydrocarbon solvent manufactured by Exxon) to obtain a solution of alkyd resin with a viscosity of Y, an acid value of 4.7, and a hydroxyl value of 80. Ta. Example 8 94 parts of coconut oil fatty acid, 284 parts of trimethylolpropane, 82 parts of neopentyl glycol, 1,
100 parts of 6-hexanediol, of isophthalic acid
222 parts of 1,4-cyclohexanedicarboxylic acid
The reaction was carried out in the same manner as in Example 4, except that 344 parts and 5 parts of diethyl phosphite were used, and then the nonvolatile content was reduced to 65% with xylene.
adjusted to have a viscosity of Z ₃ , an acid value of 6.1, and
A solution of an alkyd resin having 91 hydroxyl groups was obtained. Comparative Example 1 The amounts of coconut oil and pentaerythritol were increased to 380 parts and 152 parts, respectively, and the reaction temperature was increased.
After carrying out the alcohol exchange reaction in the same manner as in Example 1 except that the temperature was changed to 230°C, 376 parts of phthalic anhydride, 94 parts of pentaerythritol, 48 parts of trimethylolpropane, and "Supervecamine P- A solution of an alkyd resin having a viscosity Z, an acid value of 73, and a hydroxyl value of 4.2 was obtained in the same manner as in Example 1, except that 40 parts of "198" and 40 parts of xylene were added. Comparative Example 2 A solution of an alkyd resin having a viscosity of U, an acid value of 6.0, and a hydroxyl value of 77 was obtained in the same manner as in Example 1, except that "Supervecamine P-198" was not used at all. Comparative Example 3 After charging 320 parts of coconut oil, 221 parts of glycerin, and 0.15 parts of lithium hydroxide and carrying out an alcohol exchange reaction at 230°C for 1 hour, 29 parts of ethylene glycol and hexahydrophthalic anhydride were added.
The viscosity R-
A solution of an alkyd resin having an acid value of 4.6 and a hydroxyl value of 66 was obtained. Using the various alkyd resins obtained in the above Examples and Comparative Examples, paints were prepared separately according to the formulations shown in Table 1. Dilute with a mixed solvent of butanol = 40/30/20/10 (volume ratio) using a No. 4 food cup for 23 seconds, then spray with air for 30 to 30 seconds.
Painted to a film thickness of 35μm, then heated at 140℃ for 30 minutes.
A test piece was prepared by baking for a minute. Various coating film performance tests were conducted on each test piece. The results are summarized in Table 2.

【table】

【table】

【table】

[Table] Test method and evaluation criteria Sharpness: Judging the surface condition of the paint film with the naked eye ◎...Excellent ○...Good △...Average ×...Good ××...Poor Gloss: Murakami gloss meter ∠60° Reflectance (%)
Displayed hardness: "Scratch" caused by "Mitsubishi Uni" pencil,
Displayed with the minimum hardness that will no longer occur H ⁺ ...H ~ 2H F ^- ... HB ~ F Acid resistance: After dropping 2 to 3 drops of 5% H ₂ SO ₄ aqueous solution on the paint film and leaving it for a day and night. Judging by the degree of "glossy" of the coating film ◎...Excellent ○...Good △...Average ×...Good ××...Not gasoline resistance: 2 for "Nisseki Gold Gasoline"
Judging by the degree of coloration and/or softening of the paint film after immersion for a period of time ◎...Excellent ○...Good △...Average ×...Possible ××...Poor Weather resistance: In the case of accelerated weather resistance, sunlight The gloss retention rate (%) is expressed after 1000 hours and 1500 hours of exposure to the zaometer, respectively.On the other hand, in the case of outdoor exposure, the gloss retention rate (%) is expressed after exposure to the suburbs of Bangkok, Thailand for 1 year and 2 years, respectively. Discoloration due to wax: "Ten-all" on flannel cloth (car wax manufactured by Wilson, USA)
Pigment dispersibility: For red pigments and yellow pigments, the coating film is rubbed 30 times and determined by the degree of coloration on the cloth.
Using ``Fastogen Super Red BN'' with 10% PCW and ``Fastogen Yellow 4192'' (benzimidazolone pigment manufactured by Dainippon Ink & Chemicals Co., Ltd.) with 15% PCW, they were kneaded in a sand mill for 1 hour. Determined by the presence or absence of structural viscosity of the paint after it has been thickened Good: No viscosity Poor: viscous

Claims (1)

[Claims] 1. In an alkyd resin paint containing as a main film-forming component an alkyd resin obtained using a polyhydric carboxylic acid component and a polyhydric alcohol component, the alkyd resin contains an alicyclic carboxylic acid as the carboxylic acid component. The molar ratio of both carboxylic acids to aromatic carboxylic acid is 50:50 to 95:5, and the residues based on these two carboxylic acids are 30% by weight or more based on the resulting alkyd resin. It is obtained by condensing an ester-forming inorganic or organic phosphorus compound so that the residue of the inorganic or organic phosphorus compound is 0.5 to 5% by weight based on the resulting alkyd resin. The above-mentioned alkyd resin paint is characterized in that the oil length is 50% or less.