JP2699172B2 - Paint composition - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a coating composition, and more particularly, to a high solidification which has a much higher solid content than conventional coatings, and has high cross-linking reactivity. The present invention relates to a coating composition particularly useful as a top coat for products and the like.

2. Description of the Related Art Solvent-based coating compositions containing a film-forming polymer, an organic solvent, a cross-linking agent, and a curing catalyst as main components have been widely used as a top coat for automobiles, home appliances, decorative articles, and the like. In addition to the properties, the finished appearance such as smoothness and gloss of the coating film and various desired physical properties are always problematic.

High solidification to increase the resin content of the coating composition is particularly important.For example, in the case of an automotive coating, in the case of a polyester-based resin, it is desirable to reduce the molecular weight of the resin or to incorporate a so-called soft monomer to obtain a solid content. Containing up to about 50 to 52% by volume solids (Vol NV). However, high solidification by the prior art is the limit, and further increasing the solid content is unsuitable as a coating for automobiles due to a decrease in appearance and a decrease in coating film performance.

On the other hand, acrylic resins are also intended to be high-solid by reducing the number average molecular weight to about 1,000 to 2,000 or lowering the glass transition temperature, for example. % And about 40-45% for color base paints, and higher solids are considered to be unsuitable due to a decrease in coating film performance and the like. In addition, blends of polyester resins or acrylic resins with other low viscosity polymers have been tried, but not only because the solids content by volume cannot be made too large, but also due to compatibility and deterioration of coating film performance, etc. Has not achieved the purpose of

Problems to be Solved by the Invention Therefore, a new low-viscosity, high-crosslinking-reactive resin is used as the main resin component of the paint, and it is possible to make a much higher high solid than before, and the coating film appearance and coating film performance are excellent. It is an object of the present invention to provide a coating composition useful for overcoating, such as for automobiles and home appliances.

Means for Solving the Problems According to the present invention, the object of the present invention is to provide a film-forming polymer (A), an organic liquid diluent (B) supporting the polymer,
In a coating composition containing a crosslinking agent (C) and a curing catalyst (D) as main components, the film-forming polymer (A)
Is the expression (Where n is a real number of 3 to 50), which is achieved by a coating composition characterized by being an acrylic polymer or copolymer having a side chain represented by the following formula:

The film-forming polymer used in the present invention is a novel acrylic polymer or copolymer having a characteristic side chain represented by the above formula, and was first synthesized by the present inventors by the following method. Things. That is, first (Mare)
Ring-opening polymerization of tetrahydrofuran with an acrylic acid halide and a Lewis acid metal salt and terminating the polymerization reaction with water or an aqueous alkali solution or quaternary ammonium hydroxide, or ring-opening polymerization of tetrahydrofuran with a strong protic acid to give (meth) The polymerization reaction is stopped by a method of terminating the polymerization reaction with a metal acrylate or an amine (meth) acrylate. Wherein R is hydrogen or a methyl group; n is a real number of 3 to 50. A monomer containing a terminal hydroxyl group having a repeating unit of oxytetramethylene represented by the formula:
20 to 100 mol% of the other α, β-ethylenically unsaturated monomer 80 to 0 mol% is polymerized according to a conventional method to obtain a resin composition having a number average molecular weight of 1,000 to 10,000, which is formed into a film-forming resin. Used as a polymer.

In the method for producing the monomer, as the (meth) acrylic acid halide, for example, acrylic acid chloride, methacrylic acid chloride, acrylic acid bromide, methacrylic acid bromide and the like are used, and as the metal salt of Lewis acid, Silver antimony hexafluoride, silver tetrafluoroboronate,
Silver perchlorate or the like is used.

The reaction is carried out according to a conventional method, for example, by dropping a predetermined amount of tetrahydrofuran into a solution containing a (meth) acrylic acid halide and a Lewis acid metal salt, and heating and stirring the solution. May be added to stop the reaction at the stage of the desired degree of polymerization of oxytetramethylene. Examples of the alkaline aqueous solution include aqueous solutions of sodium hydroxide, potassium hydroxide, lithium hydroxide, and calcium hydroxide, and examples of the quaternary ammonium hydroxide include tetramethylammonium hydroxide and tetraethylammonium hydroxide. In the above reaction, a solvent that does not affect the reaction, such as dichloromethane, can be used if desired.

According to the second method, such a monomer composition is obtained by subjecting tetrahydrofuran to ring-opening polymerization with a strong protonic acid and terminating the polymerization reaction with a metal (meth) acrylate or an amine (meth) acrylate. Can be manufactured. Here, as the strong protic acid, for example, fluorinated methanesulfonic acid, trichloromethanesulfonic acid, perchloric acid, hydrofluoric acid, sulfuric acid, chlorosulfonic acid, fluorinated sulfonic acid and the like are used. Also, a combination of the above strong protonic acid and a Lewis acid such as antimony pentafluoride can be used. Examples of the metal (meth) acrylate include sodium, potassium, lithium, magnesium, calcium, barium, and strontium salts of acrylic acid or methacrylic acid. Examples of the amine (meth) acrylate include: Ammonium (meth) acrylate and the like.

 The reaction is carried out by a conventional method according to the first method.

Since the monomer composition thus obtained uses a ring-opening polymerization method of tetrahydrofuran, it is not a single compound, but a mixture of ones having a somewhat different number of oxytetramethylene chain repeating units, but as a raw material for producing an acrylic polymer. When they are used, it is not significant to separate and purify them, and it is not preferable from the viewpoint of protecting the polymerizable vinyl group. Therefore, it is sufficient if the number n of the repeating units of the oxytetramethylene chain is taken as an average value. is there.
If the number n of the repeating units is 3 or more, the intended purpose of flexibility can be achieved, so that the number can be increased to a considerably large value. Therefore, practically, it is selected up to about 100, preferably within the range of 3 to 50.

The film-forming polymer used in the present invention has the above formula Wherein R is hydrogen or a methyl group; n is a real number of 3 to 50. 20 to 100 mol% of a monomer (as a composition) and another α, β-ethylenically unsaturated monomer 80 To 0 mol% by polymerization.

The polymerization is carried out by any method such as emulsion polymerization, solution polymerization, and NAD method, and does not require any special means, but supports a film-forming polymer for the purpose of the present invention to obtain a solvent-type coating composition. It is convenient to use solution polymerization or NAD techniques using an organic liquid diluent or an organic liquid compatible therewith. For coating purposes, the acrylic polymer preferably has a number average molecular weight in the range of about 1,000 to 10,000.

Thus obtained film-forming polymer has a oxytetramethylene chain of flexible structure represented in the resin skeleton _{-COOCH 2 CH 2 CH 2 CH 2} n OH,
Further, since the resin has a reactive hydroxyl group at its side chain terminal, the resin itself is imparted with extremely desirable flexibility, has high cross-linking reactivity, and when n is about 3 to 50, is very low for a coating. It has the characteristic of being viscous and capable of providing a highly elastic coating film.

The organic liquid diluent (B), cross-linking agent (C) and curing catalyst (D) used in the coating composition of the present invention are any of those conventionally used in such solvent-type coatings, and are not particularly limited. But not for example, xylene as an organic liquid diluent, aromatic hydrocarbons such as toluene, aliphatic hydrocarbons, esters, ketones, alcohols or mixtures thereof; aminoplast resins as crosslinkers, for example,
Polyisocyanate compounds such as butoxymethyl melamine resin, methoxymethyl melamine resin, methoxybutoxy mixed, alkyl etherified melamine resin such as etherified methyl melamine resin, urea resin, or isocyanate group free or protected polyisocyanate compound; curing catalyst Preferred examples thereof include strong protic acids such as paratoluenesulfonic acid and dodecylbenzenesulfonic acid, or organic amine salts thereof, and organic metal compounds such as dibutyltin dilaurate and dibutyltin oxide. The mixing ratio of each of these components can be varied widely according to the purpose of use and the like, as in the case of the conventional solvent-type coating composition, but usually, the crosslinking agent (C) is used as the film-forming polymer (A). 5 to 100 parts per 100 parts (parts by weight, hereinafter the same); organic liquid diluent (B) is the total amount of (A) and (C)
Designed within the range of 10 to 2000 parts per 100 parts. However, if necessary, the curing catalyst (D) may be used in the range of 0.1 to 10 parts per 100 parts of the total amount of (A) and (C).
The coating composition of the present invention can be used as a clear, but can also be used as a color base coating containing a metal or non-metal content, and if desired, a surface conditioner, an ultraviolet absorber, an antioxidant, and the like. Optional paint additives can also be added.

As described above, since the coating composition of the present invention uses a novel resin having low viscosity, high crosslinking reactivity and high elasticity, the coating composition of the present invention is much higher than the limit of 45 to 50% by volume solid content using a conventional acrylic resin. Solidification is possible, for example, volume solids 55
Even with paints of about 65% or higher, high cross-linking reactivity and high elasticity of the coating film due to high elasticity can be achieved, and it is particularly useful as a top coating for automobiles and other coatings.

Hereinafter, the present invention will be described in detail with reference to Examples, but it goes without saying that the technical scope of the present invention is not limited to these Examples.

<< Production of Monomer a Constituting Film-Forming Polymer >> Monomer a is a compound represented by the following structural formula.

Here, R: H or CH ₃ n: a real number of 3 to 50 Production Example 1 After thoroughly replacing the nitrogen in a well-dried 3 l flask with a high-purity nitrogen gas having a water content of 1 ppm or less, 1380 g of distilled THF and antimony hexafluoride were distilled out. 73.8 g of silver was carefully charged so as not to bring in moisture, and cooled to -40 ° C with stirring. After reaching the predetermined temperature, 22.5 g of methacrylic chloride dissolved in 180 g of THF was added. The reaction was continued at the same temperature, and after 180 minutes, 450 ml of ion-exchanged water was added to stop the reaction. After completion of the reaction, the reaction solution was taken into a separating funnel, ether was added, and then ion-exchanged water was added, followed by vigorous shaking.
After standing, the aqueous layer was removed. After that, repeat the washing several times,
The ether layer was separated.

After dehydration with anhydrous sodium sulfate, use an evaporator
At 20 ° C., the ether was removed under reduced pressure to obtain a monomer a-1.

As a result of measurement by IR and ¹ H-NMR, THF of monomer a-1 was measured.
The average degree of polymerization n was 6.

Production Example 2 In the same manner as in Production Example 1, a reaction was carried out under the polymerization conditions of -20 ° C. and 10 minutes, followed by purification to obtain a monomer a-2.

As a result of measurement by IR and ¹ H-NMR, the T
The HF average polymerization degree n was 10.

<< Production of Film-Forming Polymer >> Production Example 3 90 parts of Solvesso-100 (Note 1) were charged into a reaction vessel equipped with a stirrer, thermometer, reflux condenser, nitrogen gas inlet tube and dropping funnel, and nitrogen was added. After heating to 150 ° C. while introducing a gas, the following mixture was dropped at a constant speed over 3 hours using a dropping funnel.

Mixture A Monomer a-1 60 parts Methyl methacrylate 40 parts t-butylperoxy-2-ethylhexanoate 5 parts After the completion of dropping of the above mixture, the mixture was kept warm for 30 minutes to obtain t-butylperoxy-2-ethylhexanoate. A mixture of 0.5 part and 10 parts of Solvesso-100 was dropped at a constant speed in 30 minutes. After completion of the dropwise addition, the mixture was aged at 150 ° C. for 1 hour and then cooled.

The solvent was removed from the obtained solution to a predetermined solid content concentration using an evaporator to obtain a resin solution A-1. Table 2 shows the properties of the obtained resin and resin solution.

Production Examples 4 to 7 Reaction was carried out in the same reaction vessel and in the same manner as in Example 1 at the compositions and reaction temperatures shown in Table 1, and after removing the solvent, resin solutions A-2 to A-5 were obtained. Table 2 shows the properties of the obtained resin and resin solution.

The number average molecular weight was measured by gel permeation chromatography.

<< Production of Acrylic Resin >> Comparative Production Example 1 Using the same reaction vessel as in Production Example 1, Solvesso-10
After charging 100 parts and heating to 150 ° C., a mixture composed of a monomer having the following composition and a polymerization initiator was added dropwise over 3 hours, and the mixture was further polymerized at the same temperature for 2 hours. After the polymerization, the solvent was removed so as to obtain a predetermined nonvolatile content, thereby obtaining a resin solution B-1. The obtained resin solution had a nonvolatile content of 70%, a viscosity of X, and a number average molecular weight of 1,900.

Composition Methyl methacrylate 40 parts n-butyl acrylate 40 parts 2-hydroxyethyl methacrylate 20 parts Polymerization initiator 5.5 parts (t-butylperoxy-2-ethylhexanoate) Comparative Production Example 2 A reaction vessel similar to Production Example 1 was prepared. Using Solvesso-100
After charging 100 parts and heating to 150 ° C., a mixture composed of a monomer having the following composition and a polymerization initiator was added dropwise over 3 hours, and the mixture was further polymerized at the same temperature for 2 hours. After the polymerization, the solvent was removed so as to have a predetermined nonvolatile content, thereby obtaining a resin solution B-2. The nonvolatile content of the obtained resin solution was 70%, the viscosity was UV, and the number average molecular weight was 2,100.

Composition Styrene 20 parts n-butyl acrylate 20 parts 2-ethylhexyl methacrylate 40 parts 2-hydroxyethyl methacrylate 20 parts Polymerization initiator 5.5 parts (t-butylperoxy-2-ethylhexanoate) << Production of polyester resin >> Comparative production Example 3 In a 31-reaction kolben equipped with a heating device, a stirring device, a reflux device, a water separator, a rectification column and a thermometer, 156 parts of trimethylolpropane, 755 parts of 1,6 hexanediol, 817 parts of isophthalic acid, 180 parts of adipic acid and 3 parts of dibutyltin oxide are charged and heated and melted at 80 to 100 ° C. When stirring becomes possible, stirring is started, and the reaction temperature is raised to 180 ° C. When the reaction condensed water starts to be generated, the temperature is raised to 210 ° C. at a uniform rate over 3 hours while distilling out of the system,
When the temperature reaches 10 ° C., the reaction is continued at the same temperature for 2 hours. Thereafter, xylol is added to the reaction kolben, and the condensation reaction is continued by the xylol reflux method. When the resin acid value reaches 10, the reaction is terminated and the mixture is cooled to 100 ° C. After cooling, 500 parts of xylol was added to obtain a polyester resin solution B-3. The obtained resin solution has a nonvolatile content of 75% and a viscosity T-
U, the number average molecular weight was 1100.

Example 1 94 parts of the resin solution A-1 obtained in Production Example 3, Cymel 303
(Note 2) 36 parts, rutile-type titanium oxide 81 parts, toluene 12
Parts, n-butanol 12 parts, Modaflow (Note 3) 0.2 parts,
2.4 parts of p-toluenesulfonic acid trimethylamine salt is added to a tin can, and stirred with a disper for 15 minutes to obtain a white enamel paint. Further, a butyl acetate / xylol / solvesso-100 = 2/2/1 mixed solvent is used. The mixture was diluted with a 4 Ford cup to a viscosity of 23 seconds (20 ° C.) to obtain a white enamel coating liquid W-1.

 The volume solid content of this coating liquid was 60%.

Examples 2 to 4 In the same manner as in Example 1, using the resin solutions A-2 to A-4 obtained in Production Examples 4 to 6, respectively, the white enamel coating liquid W
-2 to W-4 were obtained.

 Table 3 shows the solid content by volume.

Example 5 94 parts of the resin solution W-5 obtained in Production Example 6, Sumidur N
-3200 (Note 4) 20 parts, rutile type titanium oxide 78 parts, toluene 12 parts, butyl acetate 12 parts, Modaflow 0.2 parts are added to a tin can, and stirred with a disper for 15 minutes to obtain a white enamel paint, and acetic acid is further added. Butyl / Xylol / Solvesso-10
0 = viscosity with # 4 Ford cup using mixed solvent of 2/2/1
The mixture was diluted for 23 seconds (20 ° C.) to obtain a white enamel coating liquid W-5.

 Table 3 shows the volume solid content of this coating liquid.

Comparative Example 1 A white enamel coating liquid W-6 was obtained in the same manner as in Example 1 except that 120 parts of the resin solution B-1 obtained in Comparative Production Example 1 was used.

 Table 3 shows the volume solid content of this coating liquid.

Comparative Example 2 A white enamel coating liquid W-7 was obtained in the same manner as in Example 1 except that 112 parts of the resin solution B-3 obtained in Comparative Production Example 3 was used.

 Table 3 shows the volume solid content of this coating liquid.

Example 6 107 parts of resin solution A-1 obtained in Production Example 1, Cymel 303 2
4 parts, Alpaste 1109MA (Note 4) 18 parts, toluene 12
Parts, butyl acetate 6 parts, N-butanol 6 parts, Modaflow
0.2 parts, p-toluenesulfonic acid trimethylamine salt 2.4
To a tin can, and stirred with a disper for 15 minutes to obtain a metallic base paint. Using a mixed solvent of toluene / ethyl acetate / solvesso-100 = 5/3/2, viscosity of 23 seconds with a # 4 Ford cup ( (20 ° C.) to obtain a metallic base coating liquid M-1.

 Table 3 shows the volume solid content of this coating liquid.

Comparative Example 3 A metallic base coating liquid M was prepared in the same manner as in Example 6 except that 137 parts of the resin solution B-1 obtained in Comparative Production Example 1 was used.
-2 was obtained.

 Table 3 shows the volume solid content of this coating liquid.

Example 7 94 parts of the resin solution A-5 obtained in Production Example 7, Cymer 303 36
Parts, n-butanol 6 parts, Solvesso-100 24 parts, Motaflow 0.2 parts, ultraviolet absorber 1 part, paratoluenesulfonic acid trimethylamine salt 2.4 parts are added to a tin can, and stirred with a disper for 15 minutes to obtain a clear paint. The solvent was diluted with a # 4 Ford cup to a viscosity of 27 seconds (20 ° C.) using a mixed solvent of Solvesso-100 / solvesso-150 (Note 5) = 2/1 to obtain a metallic clear coating liquid CL-1.

 Table 3 shows the volume solid content of this coating liquid.

Comparative Example 4 A metallic clear coating liquid was prepared in the same manner as in Example 6, except that 120 parts of the resin solution B-2 obtained in Comparative Production Example 2 was used.
CL-2 was obtained.

 Table 3 shows the volume solid content of this coating liquid.

Example 8 A white enamel coating liquid W-1 obtained in Example 1 was spray-coated on a mild steel sheet subjected to degreasing and zinc phosphate treatment, using a coated plate coated with an electrodeposition primer for automobiles and an intermediate coating surfacer, and sprayed at room temperature. After standing for 10 minutes, it was baked at 140 ° C. for 30 minutes to form a white coating film [I]. Table 4 shows the performance test results of this coating film.

Examples 9 to 11 and Comparative Examples 5 to 6 White coating films [II] to [VI] were obtained in the same manner as in Example 8 using the coating liquids of Examples 2 to 4 and Comparative Examples 1 and 2. . Table 4 shows the performance test results of these coating films.

Example 12 A white enamel coating liquid W-5 obtained in Example 5 was spray-coated on a mild steel sheet subjected to degreasing and zinc phosphate treatment, using a coated plate coated with an electrodeposition primer for automobiles and an intermediate coating surfacer. After standing for 10 minutes, it was baked at 120 ° C. for 30 minutes to obtain a white coating film [VII]. Table 4 shows the performance test results of this coating film.

Example 13 A mild steel sheet subjected to degreasing and zinc phosphate treatment was spray-coated with the metallic base coating liquid M-1 obtained in Example 6 using a coated plate coated with an electrodeposition primer for automobiles and an intermediate coating surfacer, and then heated at room temperature. After standing for 3 minutes, the clear coating liquid CL-1 obtained in Example 7 was spray-coated, and
After standing for 1 minute, it was baked at 140 ° C. for 30 minutes to form a 2-coat 1-baked metallic coating [VIII]. Table 4 shows the performance test results of this coating film.

Comparative Example 7 Example 12 was performed using the metallic base coating liquid M-2 obtained in Comparative Example 3 and the clear coating liquid CL-2 obtained in Comparative Example 4.
In the same manner as described above, a two-coat one-bake metallic coating film [IX] was obtained. Table 4 shows the performance test results of this coating film.

* 1, * 6 Aromatic solvent manufactured by Esso Standard * 2 Methylated melamine manufactured by Mitsui Toatsu Chemicals * 3 Leveling agent manufactured by Monsanto * 4 Bullet-type polyisocyanate manufactured by Sumitomo Bayer * 5 Aluminum pigment manufactured by Toyo Aluminum Note 7: Appearance Judgment by visual observation ○: Excellent △: Slightly poor ×: Poor Note 8: Adhesion The coating film is cut with a sharp blade at intervals of 1 mm vertically and horizontally to reach the material steel surface, and 100 squares After making the eyes, press the commercially available cellophane tape on this, and count the remaining squares of the test piece after peeling off the cellophane tape, the intermediate coating film and the top coating film, the metallic base coating film and the clear coating film are counted. The adhesion was confirmed.

Note 9: Rubbing test The coating film surface was rubbed with gauze soaked with methyl ethyl ketone, and the curability of the coating film was evaluated by the number of reciprocations until one change of the coating condition, with one reciprocation being one.

Note 10: Water resistance The coated film test piece was immersed in warm water of 40 ° C. for 240 hours, and evaluated in the same manner as in the adhesion test by the residual ratio of ² × ² 100 squares.

Note 11: Accelerated weathering resistance Sunshine Weatherometer (Suga Test Machine) 600
Time irradiation, then wet tester (50 ° C, 98% relative humidity)
Performing the test in 96 hours is one cycle,
This was repeated twice to evaluate the state of the coating film and the adhesion. The adhesion was evaluated in the same manner as in Note 7 by the residual ratio of 100 squares of ² mm ² .

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yoshio Eguchi 19-17 Ikedanakamachi, Neyagawa-shi, Osaka Japan Paint Co., Ltd. (72) Koji Asakura 19-17 Ikedanakamachi, Neyagawa-shi, Osaka Japan Paint Co., Ltd. Inside

Claims (6)

(57) [Claims] 1. A coating composition comprising a film-forming polymer (A), an organic liquid diluent (B) carrying the polymer, a crosslinking agent (C) and a curing catalyst (D) as main components. The film-forming polymer (A) has the formula (Where n is a real number of 3 to 50) A coating composition characterized by being an acrylic polymer or copolymer having a side chain represented by the following formula: 2. The crosslinking agent (C) is 5 to 100 parts per 100 parts of the film-forming polymer (A), and the organic liquid diluent (B) is mixed with the film-forming polymer (A) and the crosslinking agent (C). The composition according to claim 1, wherein the weight ratio is 10 to 2000 parts per 100 parts of the total amount of (C) [(A) + (C)]. 3. A curing catalyst (D) comprising a total amount of a film-forming polymer (A) and a crosslinking agent (C) [(A) + (C)] 100
2. The composition of claim 1 wherein the amount is from 0.1 to 10 parts per part. 4. The composition according to claim 1, wherein the organic liquid diluent (B) is an aliphatic hydrocarbon, an aromatic hydrocarbon, an ester, a ketone, an alcohol or a mixture thereof. 5. The composition according to claim 1, wherein the crosslinking agent (C) is an aminoplast resin or a polyisocyanate compound in which isocyanate groups are free or protected. 6. The composition according to claim 1, comprising a metal or non-metallic pigment.