JPH0464351B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a resin composition for paints, and more specifically, a paint containing a new resin obtained by silicone-modifying and alkyleneimine-modifying a resin having hydroxyl groups and carboxyl groups, such as polyester resins, alkyd resins, and acrylic resins. The present invention relates to a resin composition for use. BACKGROUND OF THE INVENTION It is required to obtain coating compositions with excellent weather resistance in various fields, particularly in top coatings for automobile bodies, coil coatings, and the like. Among these, resin-based coating compositions made by blending oil-free polyester resin with aminoaldehyde resin, etc., have long been attracting attention because of their excellent weather resistance, mechanical properties of the coating film, and interlayer adhesion. It is easy to occur, and the painted surface looks blurred,
It has not been widely put into practical use for reasons such as poor gloss and poor compatibility with amine resins. Recently, by using saturated alicyclic polybasic acid or saturated alicyclic polybasic acid and aromatic polybasic acid as part of the acid component of oil-free polyester resin, paintability, glossiness, and compatibility with amine resins have been improved. ,
Improvements in gloss, hardenability, etc. can be obtained, and weather resistance can be improved by modifying polyester resins with reactive organopolysiloxane resins. It has been discovered that silicone modification can further improve workability (pin, sag, and cissing resistance), shear feel, weather resistance, etc., and polyester paints are suddenly attracting attention as top coat paints for coil coatings in automobiles, etc. It came to this. However, when polyester resin is modified with silicone, although weather resistance is generally improved,
It has the disadvantage that recoatability is poor when the same paint is applied over and over again due to surface tension and other factors. Therefore, in order to make full use of the features of polyester resin and to put it into widespread practical use, especially as a top coat, it is essential to improve not only the weather resistance but also the recoatability of the paint, and the various previous proposals have not answered this question. . In view of the above, the present inventors conducted extensive research and found that weather resistance was improved by silicone modification of a resin having hydroxyl and carboxyl groups, and that poor recoatability due to silicone modification was improved by alkyleneimine modification. Having learned that this can be avoided, we have completed the present invention. That is, according to the present invention, a resin having a hydroxyl group and a carboxyl group has the formula (In the formula, R is a monovalent organic group bonded to silicon through a carbon-silicon bond; R' is hydrogen, a _C1 to _C20 alkyl group or an aryl group; n and m each have a value of 4 or less, provided that n+m4) The number average molecular weight is approximately
There is provided a resin composition obtained by reacting an organopolysiloxane resin having 500 to 2000 carbon atoms and an alkylene imine compound having at least one alkylene imine ring having 2 to 3 carbon atoms in any order. In the present invention, resins having hydroxyl groups and carboxyl groups, such as polyester resins, alkyd resins, acrylic resins, etc., are used as the base resin. These can be any conventionally known coating resins as long as they have hydroxyl and carboxyl groups. That is, polyester resin is obtained from a polybasic acid component arbitrarily selected from aromatic, aliphatic, saturated alicyclic polybasic acids, etc. and a normal polyol component, and alkyd resin is obtained by modifying polyester resin with oil or fatty acid. and
Acrylic resins are common types of resins obtained by polymerization or copolymerization of α,β-ethylenically unsaturated compounds. The inventors have discovered that the weather resistance of such resins can be significantly improved when the hydroxyl groups of such resins are silicone modified by reacting with reactive organopolysiloxane resins. In this case, the reactive organopolysiloxane resin used is, for example, the formulas described in JP-A-56-157461 and JP-A-56-157462; (In the formula, R is a monovalent organic group bonded to silicon through a carbon-silicon bond; R' is hydrogen, a _C1 to _C20 alkyl group, or an aryl group; n and m each have a value of 4 or less, and n+m is 4 Organopolysiloxane resins with a number average molecular weight of about 500 to 2000 are preferred; It is desirable to have two or more functional groups in the base resin, and silicone modification is performed by dehydration, dealcoholization, etc. between these functional groups and the hydroxyl functional group of the base resin. Examples of the resin include Z-6018 (Dow Corning product,

[Formula] R= _CH3

[Formula] Molecular weight 1600), Z-6188 (Dow Corning product, R= _CH3

[Formula] molecular weight 650), Sylkyd50, DC-3037 (Dow Corning product), KR-216, KR-218, KSP-1 (Shin-Etsu Silicone product), TSR-160, TSR-165 (Tokyo Shibaura Electric Co., Ltd. product) products), SH-5050, SH-6018, SH-
Various products such as 6188 (product of Toray Silicone Co., Ltd.) are commercially available, and any of them can be suitably used. Regarding silicone modification of the base resin, it is generally preferable to react 20 to 97 parts of the base resin with 80 to 3 parts of the reactive organopolysiloxane resin in solid weight ratio. This is because if the organopolysiloxane resin is less than 3 parts by weight, no improvement in weather resistance will be observed, and if it exceeds 80 parts by weight, the compatibility between the base resin and the organopolysiloxane resin will deteriorate and it will become difficult to react. be. The present inventors have further discovered an important fact that poor recoatability resulting from silicone modification of the base resin can be very effectively improved by alkyleneimine modification. As mentioned above, the base resin carries a carboxyl group, and this has 2 carbon atoms.
When a compound having at least one alkylene imine ring of ~3 is reacted, the imine ring is cleaved and alkylene imine modification of the base resin is achieved, and such modification effectively prevents poor recoatability due to silicone modification of the base resin. be given The alkylene imine compounds used in the present invention include, for example, compounds represented by the following formula. Here, R ₁ , R ₂ , R ₃ , R ₄ and R ₅ are each hydrogen, alkyl having 20 or less carbon atoms such as methyl, ethyl, and propyl; aryl such as phenyl; alkaryl such as tolyl and xylyl; benzyl, phenethyl, etc. alkyl, R ₅ is hydrogen or alkyl usually having 6 or less carbon atoms, n is an integer of 0 or 1; Incidentally, the above group may contain a substituent that does not adversely affect the basic properties of the imine during the reaction. Such substituents include carbonyl, cyano, halogen, amino, hydroxyl, alkoxy, carbalkoxy and nitrile. Examples are cyanoalkyl, haloalkyl, aminoalkyl, carbalkoxyalkyl and aryl, alkaryl and aralkyl with similar substituents. Certain compounds in which two or more of the above groups are bonded cannot be obtained due to steric hindrance or interaction. For this reason, R ₁ to _{R 6} are often hydrogen, and specific compounds are shown below. Ethyllenimine, 1,2-propyleneimine, 1,3-propyleneimine, 1,2-dodecylenimine, 1,1-dimethylethyleneimine,
Phenylethyleneimine, tolylethyleneimine, benzylethyleneimine, 1,2-diphenylethyleneimine, 2-hydroxyethylethyleneimine, aminoethylethyleneimine, 2-methylpropyleneimine, 3-chloropropylethyleneimine, p-chloroethyleneimine enylethyleneimine, methoxyethylethyleneimine, carboethoxyethylethyleneimine, N-ethylethyleneimine, N-butylethyleneimine, N-(2-
aminoethyl)ethyleneimine, N-(2-hydroxyethyl)ethyleneimine, N-(cyanoethyl)ethyleneimine, N-phenylethyleneimine, N-triethylethyleneimine, N-(p
-chlorophenyl)ethyleneimine, N-(2-
Carboethoxy-1-ethyl)ethyleneimine. Particularly preferred imines in view of their usability and effectiveness are ethyleneimine, 1,2-propyleneimine and N-(2-hydroxyethyl)ethyleneimine. In addition to the above preferred alkylene imine compounds, alkylene imine compounds other than those of the general formulas above can also be used. For example, ethylene-1,
Satisfactory results can also be obtained using alkylene imines containing one or more alkylene imine rings, such as 2-bisaziridine and 1,2,4-tris(2-1-aziridinylethyl) trimellitate. can. In this invention, the term alkylene imine compound includes all the above-mentioned alkylene imines, including those substituted. In the present invention, it is necessary that the alkylene imine compound is reacted in an amount corresponding to the resin acid value of the base resin from 0.1 to 50. In other words, when (molecular weight of alkylene imine compound)/(number of alkylene imine groups contained in one molecule of alkylene imino compound)=M, 2×10 ^-4 M to 1×10 ^-1 Mwt with respect to the base resin. % of alkyleneimine compounds need to be reacted. This is because if the above lower limit is not met, the effect of alkyleneimine modification cannot be sufficiently obtained, and if the amount exceeds the amount equivalent to the resin acid value of 50, yellowing will occur when formed into a film and the film performance will deteriorate significantly. This is because it has been recognized that in some cases, curing is insufficient when used with a crosslinking agent or a crosslinking agent. Both silicone modification and alkyleneimine modification of the base resin can be easily achieved by simply mixing the raw resin and reactant in the presence or absence of a solvent and heating the mixture to 200°C or lower, preferably 150°C or lower. In addition, the present inventors particularly prefer that the base resin is first modified with silicone and then modified with alkyleneimine, but it is also possible to perform alkyleneimine modification first and then react with organopolysiloxane. It has been found that sufficient effects can be achieved, and therefore, in the present invention, silicone modification and alkyleneimine modification can be performed in any order, and if desired, both can be performed simultaneously. be. Although the present invention is applicable to any base resin having hydroxyl and carboxyl groups, it is particularly applicable to polyester resins, in which at least 25% of the acid component is
By applying it to a polyester containing preferably at least 40% saturated alicyclic polybasic acid, it is possible to obtain significantly superior weather resistance and recoatability as well as workability, appearance, and film performance as a top coat. I'm finding out. The present invention will be explained below with reference to Examples. Example 1 19.4 parts of hexahydrophthalic anhydride and trimethylolpropane were placed in a reaction tank equipped with a heating device, a stirrer, a reflux device, a water separator, a rectification column, and a temperature system meter.
Add 22.6 parts of neopentyl glycol, 26.5 parts of neopentyl glycol, and 30.1 parts of 1.6-hesysandiol and heat. Once the raw materials have melted and can be stirred, start stirring,
Raise the temperature to 210℃. The temperature is raised from 210°C to 230°C at a constant rate over 2 hours, and the condensed water produced is distilled out of the system. When the temperature reaches 230, the temperature is kept constant and the resin is cooled down to an acid value of 1.0. After cooling, 83.1 parts of isophthalic acid is added and the temperature is raised to 190°C again.
The temperature is raised from 190°C to 210°C at a constant rate over 3 hours, and the condensed water produced is distilled out of the system. 210℃
When the temperature reached 3.2 parts of xylol was added to the reaction tank.
Switch to condensation in the presence of a solvent and cool at resin acid number 20.0. After cooling, 29.3 parts of xylol and 75.9 parts of cellosolve acetate were added to obtain oil-free polyester resin varnish A (referred to as base resin A). Subsequently, 28.7 parts of reactive silicone resin DC-3037 (manufactured by Dow Corning) and TBT as a condensation catalyst were added.
-100 (tetrabutyl titanate manufactured by Nippon Soda Co., Ltd.) 0.38 part is charged, heated and stirred. reaction temperature
Keep the temperature constant at 140°C, and cool it when the amount of methanol distilled out reaches 75% of the theoretical methanol amount (the amount of methanol removed when the methoxy groups of the reactive silicone resin react with the hydroxyl groups of the 100% polyester resin). , and finally N-(2-hydroxyethyl)
Ethyleneimine (trade name of Sogo Yakuko Co., Ltd.)
HEEI) 0.9 part (The acid value of the resin consumed by the reaction is
3.0), heated and stirred at 80°C for 1 hour, and then cooled. After cooling, 5.8 parts of xylene and 13.6 parts of cellosolve acetate were added to obtain alkyleneimine-modified silicone polyester resin varnish 1. This varnish has a non-volatile content of 60.5% and a varnish viscosity of R
-S (Gardner viscosity 25°C) resin acid value was 15.0. In addition, DC-3037 used in the synthesis example is a silicone resin manufactured by Dow Corning, and the methoxy group content is
18wt%, methyl group and phenyl group as R 70/
It is a reaction-produced organopolysiloxane resin with a molar ratio of 30 and a number average molecular weight of 820, and it is estimated to be R _1.57 Si(OCH ₃ ) _0.71 O _0.86 , n = 1.57, m = 0.71. There is. Examples 2 and 3 The same base resin A as in Example 1 was used, and silicone modification was carried out in exactly the same manner as in Example 1. lastly
1.8 parts and 3.0 parts of HEEI, respectively (resin acid value consumed by reaction corresponds to 6.0 and 10.0, respectively)
was added, and alkyleneimine-modified silcone polyester resin varnishes 2 and 3 were obtained in the same manner. The characteristic values of these varnishes are shown in Table 1. Example 4 A condensation reaction was carried out in the same manner as in Example 1 using the composition shown in Table 1, and the resin was cooled to reach a resin acid value of 60.0. (This is referred to as base resin B). After cooling, silicone modification and alkyleneimine modification were performed in the same manner as in Example 1 to obtain alkyleneimine modified silicone polyester resin varnish 4. The characteristic values of this varnish are shown in Table 1. Example 5 Coconut oil was transesterified in a conventional manner using the composition shown in Table 1, then subjected to a condensation reaction in the same manner as in Example 1, and cooled to a resin acid value of 20.0. (This is referred to as base resin C.) After cooling, silicon modification and alkylene imine modification were performed in the same manner as in Example 1 to obtain alkylene imine modified silicone alkyd resin varnish 5. The characteristic values of this varnish are shown in Table 1. Example 6 Silicon modification was carried out under the same conditions as in Example 1, using A as the base resin and KR-213 (manufactured by Shin-Etsu Silicone Co., Ltd.) as the reactive silicone resin. Subsequently, ethyleneimine (manufactured by Nippon Shokubai Kagaku Kogyo Co., Ltd.) was used as an alkylene imine compound and reacted under the same conditions as in Example 1 to obtain alkylene imine modified polyester resin varnish 6. The characteristic values of this varnish are shown in Table 1. The KR-213 used in this example is a silicone resin manufactured by Shin-Etsu Silicone Co., Ltd., with a methoxy group content of 20 wt% and a methyl group and a phenyl group as R.
It is a reactive organopolysiloxane resin containing a molar ratio of 60/40 and a number average molecular weight of 600, and is estimated to be R _1.6 Si(OCH ₃ ) _0.8 O _0.8 , n = 1.6, m = 0.8 if shown in the numerical formula. has been done. Examples 7-9 A condensation reaction was carried out in the same manner as in Example 1 using the compositions shown in Table 1, and the resins were cooled to give acid values of 20.0, 30.0, and 40.0, respectively. (These are referred to as base resins D, E, and F.)
After cooling, DC- corresponds to base resin/reactive silicone resin (solid content ratio) = 95/5, 55/45, 40/60.
Silicon modification was carried out under the same conditions as in Example 1 by adding 3037 to each. Subsequently, alkyleneimine modification was performed in the same manner as in Example 1 to obtain alkyleneimine modified silicone polyester resin varnishes 7, 8, and 9. The characteristic values of this varnish are shown in Table 1. Example 10 After charging 45 parts of xylene and 50 parts of cellosolve acetate into a reaction tank and raising the temperature to 130°C, 15 parts of styrene (ST) and 42.2 parts of n-butyl methacrylate (n-BMA) were added. , 16.6 parts of lauryl methacrylate (LMA), 23.2 parts of 2-hydroxyethyl methacrylate (2HEMA), 3.0 parts of methacrylic acid (MAA), 2.0 parts of t-butylperoxy 2-ethylhexanoate, and 0.3 parts of lauryl mercaptan. The solution was added dropwise at a uniform rate over 3 hours.
After the dropwise addition was completed, the mixture was kept warm for 30 minutes, and then a mixed solution of 1.0 part of t-butyl peroxy 2-ethylhexanoate and 5 parts of xylene was added dropwise at a uniform rate over a period of 30 minutes. After the dropwise addition was completed, the mixture was kept warm for 2 hours and then cooled. (This is referred to as base resin G.) After cooling, add 17.6 parts of DC-3037 to 140
While distilling methanol out of the system at °C, apply a thin layer of the reaction product on a glass plate and force dry (130 °C x 20 minutes).
do. Both before and after drying, the reaction is continued until the resins are completely compatible and become transparent. Cool when the resin becomes transparent. After cooling, continue
Add 1.1 part of HEEI, heat and stir at 80°C for 1 hour, and then cool. After cooling, 34.2 parts of xylene was added to obtain alkyleneimine modified silicoacrylic resin varnish 10. The characteristic values of this varnish are shown in Table 1. Comparative Example 1 Silicone polyester resin varnish 11 was obtained by using the base resin A of Example 1 and carrying out silicone modification in exactly the same manner as in Example 1. The characteristic values of this varnish are shown in Table 1. Comparative Example 2 Using the base resin C of Example 5, silicone deformation was carried out in exactly the same manner as in Example 1 to obtain silicone alkyd resin varnish 12. The special value of this varnish is the 1st
Shown in the table. Comparative Example 3 Using the base resin G of Example 10, silicone modification was carried out in exactly the same manner as in Example 10 to obtain silicone acrylic resin varnish 13. The characteristic values of this varnish are shown in Table 1. Comparative Example 4 The specific values of oil-free polyester resin varnish A (base resin A) obtained in the middle of the production of Example 1 are shown in Table 1.

【table】

[Table] A blue paint was prepared by dispersing and dissolving the varnishes of the above Examples and Comparative Examples as follows. Dispersion blend Titanium-95 (Note 1) 60.0 parts Shinin Blue-700-8 (Note 2) 16.0 Example/Comparative example varnish 114.0 n-butanol 18.8 208.8 Dissolved blend dispersion paste 208.8 parts Example/Comparative example varnish 126.0 Super Betsucomin J820 -60 (Note 3) 60.0 Isophorone (Note 4) 9.4 Solbetsuso 150 (Note 5) 9.4 Silicon KF-69 (Note 6) 0.05 413.65 (Note 1) Manufactured by Ishihara Sangyo Co., Ltd. White pigment (Note 2) Toyo Ink Co., Ltd. ) Blue pigment (Note 3) Dainippon Ink Co., Ltd. Butylated melamine resin (60% non-volatile content) (Note 4) Nagase Sangyo Co., Ltd. Solvent (Note 5) Etsuo Standard Oil Co., Ltd. mixed solvent ( Note 6) Surface conditioning agent manufactured by Shin-Etsu Chemical Co., Ltd. The prepared paint is isophorone/Solbetsuso 150 =
Dilute it to 1:1 with Foord Cup No. 4 for 120 seconds (20°C) and apply Bar Coater No. 30 on a coated plate that has been primed with zinc phosphate treated galvanized iron plate.
Painting and baking were carried out under the following conditions. For weather resistance test: After coating with Bar Coater No. 30, it was baked at 210℃ for 60 seconds. For recoat adhesion test After painting with Bar Coater No. 30, 230℃ x 60
Baked for seconds, then coated with the same paint again using Bar Coater No. 30 and baked at 210°C for 60 seconds. Table 2 shows the results of testing these coated plates for weather resistance (60° gloss retention % after 1500 hours on Sunshine Weather Meter (S-WOM)) and recoat adhesion. From the results in Table 2, it is clear that by alkyleneimine modification, the good weather resistance achieved by silicone modification is maintained, and furthermore, the recoat adhesion is significantly improved.

【table】

【table】

Claims (1)

[Scope of Claims] 1(A) A resin having a hydroxyl group and a carboxyl group selected from the group consisting of polyester resin, alkyd resin and acrylic resin, (B) formula (In the formula, R is a monovalent organic group bonded to silicon through a carbon-silicon bond; R' is hydrogen, a _C1 to _C20 alkyl group or an aryl group; n and m each have a value of 4 or less, provided that n+m4) An organopolysiloxane resin with a number average molecular weight of approximately 500 to 2000 represented by formula (C) (In the formula, R ₁ , R ₂ , R ₃ , R ₄ , R ₅ are each hydrogen, C ₁ -
C ₂₀ alkyl group, aryl group, aralkyl group or alkylaryl group, R ₆ is hydrogen or C ₁ to C ₆ alkyl group, n is 0 or 1
(A) and (B) have a solid content weight ratio of 97:
In a ratio of 3 to 20:80, and (C) is the resin acid value of (A)
A coating resin composition obtained by reacting in an arbitrary order in an amount corresponding to 0.1 to 50.