JPS5830347B2 - Fuck you - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polyurethane coating composition suitable for powder coating.

More specifically, the present invention relates to a polyurethane powder coating composition that provides a coating film with highly improved moisture resistance and salt water resistance compared to conventional polyurethane powder coating compositions.

It is known that powder compositions consisting of polyesters containing two or more hydroxyl groups and polyisocyanates blocked with phenol or cresol can be used as powder coatings.

However, a disadvantage of this composition is that during baking, bubbles may form in the coating, rendering it worthless.

It is also known that a powder composition of a polyester containing two or more hydroxyl groups and having a melting point of 40 DEG C. or higher and a polyisocyanate blocked with ε-caprolactam can be used as a powder coating.

A disadvantage of this composition is that the resulting coating film has poor moisture resistance and salt water resistance.

In view of these circumstances, the present inventors conducted research to develop a powder coating composition that does not generate bubbles and has excellent moisture resistance and salt water resistance. It has been found that a powder coating composition which completely satisfies the above objectives can be obtained by using polyisocyanates, and the present invention has been completed based on this new knowledge.

That is, in the present invention, a polyester resin having a melting point of 40° C. or higher having two hydroxyl groups and 10 alkyl groups or cyclohexyl groups is present in the molecule.

] This is a powder coating composition made of a polyisocyanate blocked with a phenol having one phenolic hydroxyl group.

The coating film obtained by powder coating using the composition of the present invention does not cause foaming, has a glossy coating surface, has good physical performance and weather resistance, and is particularly excellent in moisture resistance and salt water resistance. It is extremely useful as a paint for electrical appliances and road products.

The polyesters having at least two hydroxyl groups in the molecule and having a melting point of 40°C or higher used in the present invention include, for example, phthalic acid, isophthalic acid, terephthalic acid, maleic acid, fumaric acid, succinic acid, adipic acid, sepatic acid, and azelaic acid. , polybasic acids such as trimethic acid and, for example, ethylene glycol, diethylene glycol, furobile 7 glycol, dipropylene glycol, 1,3-butanediol, 1,4-butanediol, 1,5-bentanediol, neopentyl glycol, Hexamethylene glycol, Tecamethylene glycol, Hydroquinone bis(hydroxyethyl ether), Hydrogenated bisphenol A
, trimethylolethane, trimethylolpropane, hexanetriol, glycerin, pentaerythritol, tris(hydroxyethyl)isocyanurate, cyclohexane dimetatool, etc., by a conventional method under conditions with an excess of hydroxyl groups.

In this case, it is also possible to use two or more types of acids or polyols in combination.

Also, castor oil, higher fatty acids, etc. may be used in combination to form a so-called oil-modified polyester polyol.

The polyester polyol obtained by combining the above raw materials has a molecular weight of 500 to 4000, preferably ioo
o~3000. Hydroxyl value 10-300, preferably 20
~200. Those having an acid value of 1 to 30°C and a melting point of 60 to 120°C are preferably used.

When the melting point is below 60°C, blocking of the composition occurs, and when it is above 120°C, gelation tends to occur during melt blending.

The polyisocyanate used in the present invention may be aromatic, aliphatic, alicyclic, or araliphatic, but especially aliphatic, alicyclic, or araliphatic in which the incyanate group is not directly bonded to an aromatic ring. Polyisocyanates are preferred.

For example, titramethylene diisocyanate, hexamethylene diisocyanate (HDI), ω・J-diisocyanate dimethylcyclohexane (H6MDI), dicyclohexylmethane diisocyanate (H1□MDI), inphorone diisocyanate (IP
DI), ω・ω′-diisocyanate dimethylbenzene (MDI), methylcyclohexylene diisocyanate, etc., or an excess of these polyisocyanates,
For example, ethylene glycol, propylene glycol,
Dipropylene glycol, phthylene glycol, trimethylolpropane, hexanetriol, glycerin,
Low-molecular active hydrogen compounds such as sorbitol, pentaerythritol, castor oil, ethylenediamine, hexamethylenediamine, ethanolamine, jetanolamine, triethanolamine, or high-molecular active hydrogen compounds such as various polyether polyols, polyester polyols, acrylic polyols, etc. A polyisocyanate obtained by reacting with is suitable.

However, it is also possible to use, for example, tolylene diisocyanate, diphenylmethane diisocyanate, or reaction products of excess thereof with low molecular weight polyols.

Polyisocyanate-COO used in the present invention
RI (R1 is an alkyl group having 4 to 10 carbon atoms) or ■
Represents a cyclohexyl group.

] It is a phenol having one phenolic hydroxyl group.

The position of the substituent R is not particularly limited, but it is generally preferred to be at the para position with respect to the hydroxyl group.

The alkyl group of R1 may also be linear or branched.

Examples of phenols when R is the above ■ are 4
-phenylphenol, 2-phenylphenol, etc. Examples of phenols when R is the above ■ are 4-benzylphenol, etc. Examples of phenols when R is the above ■ are: Examples of the phenols include n-butyl 4-hydroxybenzoate, octyl 4-hydroxybenzoate, and when R is the above-mentioned (2), valacyclohexylphenol and orthocyclohexylphenol.

Among the various phenols mentioned above, phenols in which R is as described above are particularly advantageously used for the purpose of the present invention.

The blocked polyisocyanate in the present invention can be obtained by reacting a polyisocyanate with the above-mentioned phenols in a solvent without active hydrogen or without a melting medium by a known method.

In the reaction, known catalysts such as tertiary amines and organic metals may be used.

If a solvent is used and it is necessary to remove it after the reaction is completed, it can be distilled off using a spray dryer, drum dryer, thin film evaporator, etc.

In this way, a solid block polyisocyanate is produced.

In the present invention, this block polyisocyanate and polyester are mixed to form a coating composition, and the mixing ratio of both is preferably such that the equivalent ratio of the recycled isocyanate group to the hydroxyl group of the block polyisocyanate is 0.5 to 2.0. is adjusted to 0.6 to 1.5.

Any conventionally known method may be used to produce a composition suitable for powder coating from blocked polyisocyanate and polyester.

That is, the two components are dissolved and mixed in the presence of a solvent, and if necessary, a pigment, a leveling agent, a dissociation catalyst, etc. are mixed therein, and then this is made into a fine powder using a spray dryer. A method is adopted in which both components are heated and mixed at 80 to 140° C. in a molten state, pigments and other additives are kneaded therein, and the mixture is cooled to solidify and then pulverized.

The particle size of the powder is 5 to 500 microns, more preferably 1
It is 0 to 300 microns.

In practicing the present invention, it is desirable to use a block polyisocyanate dissociation catalyst for the purpose of lowering the baking temperature.

As the catalyst, any known catalyst such as amine type, metal type, etc. can be used.

The amount of catalyst added is preferably 0.01 to 5% by weight of the coating composition.

The resin composition obtained in this way is useful as a powder coating, and when powder coating is applied to the object to be coated by a method such as fluid coating or electrostatic coating, baking is performed to form the regenerated isocyanate groups. Crosslinking occurs through reaction with hydroxyl groups, resulting in a tough film.

The resulting coating film shows no so-called fading or thermal deterioration, has good physical performance, maintains good gloss and color tone over a long period of time, and has particularly excellent salt water resistance.

EXAMPLES The present invention will be specifically explained below using Examples.

Note that parts and percentages are expressed on a weight basis.

Reference Example 1 Production Example of Polyester Resin In a reaction vessel equipped with a stirrer, thermometer, and separator, 388 parts of dimethyl terephthalate, 93 parts of ethylene glycol,
(1) 135 parts of 3-butylene glycol and 36 parts of trimethylolpropane were charged and melted by heating.

After melting, continue heating while stirring until the temperature reaches 15
When the temperature reached 0°C, 9 parts of zinc acetate Q was added.

After heating to 220°C while removing by-produced methanol and reacting at this temperature for 2 hours, phthalic anhydride 1
48 parts of xylene and 24 parts of xylene were added, and the mixture was reacted at 240° C. for 3 hours while separating and removing by-product reaction water.

After that, xylene was removed under reduced pressure, and the softening point was 72°C.
A polyester resin having an H value of 77 and an acid value of 8.0 was obtained.

Example 1 In a reaction vessel equipped with a stirrer and a reflux device, 111 parts of isophorone diisocyanate and 17 parts of p-hydroxydiphenyl were added.
9 parts of ethyl acetate, 290 parts of ethyl acetate, and 0.2 parts of dibutyltin dilaurate were charged and reacted at 78 to 80°C for 4 hours, resulting in a free NCO group content of 0.1%.

Ethyl acetate was then completely removed by heating at 120°C or lower under reduced pressure, yielding a blocked isocyanate with a melting point of 75-85°C.

290 parts of this blocked isocyanate, 728 parts of the above polyester resin, titanium oxide (Tiebake R-930
500 parts (manufactured by Ishihara Sangyo ■), 5 parts of Modern Rho (manufactured by Monsanto), and 0.5 parts of 1,1,3,3-tetrabutyl-1,3-diacetoxydistanoxane were premixed for 5 minutes using a Benschel mixer.

The mixture was melt-blended in an extruder set at 100-110°C, cooled, and then heated in an atomizer to a temperature of 10-70°C.
It was ground to a particle size of μ to make a powder coating.

This paint was electrostatically applied to a mild steel plate treated with iron phosphate, and
Baking at 0° C. for 30 minutes gave a robust white coating.

The coating performance is shown in Table 1.

Example 2 550 parts of H1□MDI, 87 parts of methyl ethyl ketoxime
parts, bisphenol A 191 parts, p-hydroxylbiphenyl 271 parts, ethyl acetate 73 parts, ■・1・3・3
0.6 part of -tetrabutyl-1,3-diacetoxydistanoxane was reacted in the same manner as in Example 1, and the melting point was 100.
A blocked incyanate at ˜110° C. was obtained.

264 parts of this blocked incyanate, 728 parts of the above polyester, 496 parts of titanium oxide, 1.1.3.3-
Tetrabutyl-1,3-diacetoxydistanoxane 0
．． Table 1 shows the performance of a coating film obtained by powdering 4 parts of Modaflow and 4 parts of Modaflow in the same manner as in Example 1, electrostatically coating it, and baking it.

Example 3 185.0 parts of 0-cyclohexylphenol, 111.14 parts of inphorone diisocyanate, 296 parts of ethyl acetate
When 0.18 parts of dibutyl tin dilaure) were reacted in the same manner as in Example 1, a blocked incyanate having a melting point of 105 to 120°C was obtained.

287 parts of this blocked isocyanate, 728 parts of the above polyester, 507 parts of titanium oxide, 1.1.3.3-
Tetrabutyl-1,3-diacetoxydistanoxane 0
．． Table 1 shows the performance of a coating film obtained by powdering 5 parts of Modaflow and 5.0 parts of Modaflow in the same manner as in Example 1, electrostatically coating it, and baking it.

Example 4 22.4 parts of trimethylolpropane, 111.14 parts of isophorone diisocyanate, 102.0 parts of butyl p-hydroxybenzoate, 236 parts of ethyl acetate, and 0.14 parts of dibutyltin dilaure were prepared in the same manner as in Example 1. A blocked incyanate having a melting point of 90 to 102°C was obtained.

235.5 parts of this blocked incyane), 728 parts of the above polyester, 482 parts of titanium oxide, ■・1・3・
0.48 parts of 3-tetrabutyl-1,3-diacetoxydistanoxane and 4.8 parts of Modaflow were powdered in the same manner as in Example 1, electrostatically painted, and baked. Table 1 shows the performance of the coating film. .

Example 5 380 parts of Takenate D12ON (above), 193 parts of p-benzylphenol, 98 parts of ethyl acetate, and 0.2 parts of dibutyl tin dilaure were reacted in the same manner as in Example 1 to obtain a mixture with a melting point of 85 to 101°C. A blocked incyanate resin was obtained.

This block: 478 parts of incyanate tetrachloride resin, 728 parts of the above polyester resin, 603 parts of titanium oxide, 1
・0.6 parts of 1,3,3-tetrabutyl-1,3-diacetoxydistanoxane and 6 parts of Modaflow were powdered in the same manner as in Example 1, electrostatically painted and baked, and the coating film performance was evaluated. It is shown in Table 1.

Example 6 380 parts of Takenate D12ON (above), 262.7 parts of octyl p-hydroxybenzoate, 168 parts of ethyl acetate, and 0.24 parts of dibutyltin dilaurate were reacted in the same manner as in Example 1, and then the solvent was removed. and melting point 65-80℃
A blocked isocyanate resin was obtained.

548 parts of this blocked isocyanate resin, 728 parts of the polyester resin, 638 parts of titanium oxide, 1.1.
0.64 parts of 3,3-tetraphthyl-1,3-diacetoxydistanoxane and 6.4 parts of Modaflow were powdered in the same manner as in Example 1, and the coating film performance when electrostatically applied and baked was evaluated. It is shown in Table 1.

Comparative Example 1 380 parts of Takenate D12ON (above), 119 parts of ε-caprolactam, 105 parts of ethyl acetate, and 0.2 parts of dibutyl tin dilaure were reacted in the same manner as in Example 1 to form a block with a melting point of 92-98°C. An isocyanate resin was obtained.

408 parts of this blocked isocyanate resin, 728 parts of the above polyester resin, 568 parts of titanium oxide,
・0.5 parts of 3,3-tetrabutyl-1,3-diacetoxydistanoxane and 5 parts of Modaflow were powdered in the same manner as in Example 1, electrostatically painted, and baked. Table 1 shows the coating film performance. show.

Comparative Example 2 380 parts of Takenate D12ON (above), 108 parts of m-cresol, 90 parts of ethyl acetate, and 0.15 parts of dibutyl tin dilaure were reacted in the same manner as in Example 1 to form a block with a melting point of 85 to 95°C. An isocyanate resin was obtained.

400 parts of this blocked incyanate resin, 728 parts of the above polyester resin, 582 parts of titanium oxide, 1.1
・3,3-Tetrabutyl = 0.5 parts of 1,3-diacetoxydistanoxane and 5 parts of Modaflow were powdered in the same manner as in Example 1, electrostatically painted and baked, and the coating film performance is shown in Table 1. show.

Example 7 In a reaction vessel equipped with a stirrer and a reflux device, 111 parts of inphorone diisocyanate and 17 parts of O-hydroxydiphenyl were added.
9 parts of ethyl acetate, 290 parts of ethyl acetate, and 0.2 parts of dibutyltin dilaurate were reacted at 78 to 80°C for 4 hours, and then ethyl acetate was completely removed by heating at 120°C or lower under reduced pressure, resulting in a melting point of 75. A blocked isocyanate of ˜85° C. was obtained.

290 parts of this flocked isocyanate, 728 parts of the same polyester resin as in Reference Example 1, 500 parts of titanium oxide (Tie Bake R-930 manufactured by Ishihara Sagyo), 5 parts of Modern Low (manufactured by Monsanto), 1.1.3.3- Tetrabutyl-1
- 0.5 part of 3-diacetoxydistanoxane was premixed for 5 minutes using a Henschel mixer.

The mixture was melt-blended in an extruder set at 100-110°C, cooled, and then melt-blended in an atomizer at 10-7°C.
It was pulverized to a particle size of 0μ to obtain a powder coating.

This paint was electrostatically applied to a mild steel plate treated with iron phosphate, and
Baking at 0° C. for 30 minutes gave a robust white coating.

Salt with good coating film performance 2 An example shown in Table 8 111 parts of isophorone diisocyanate and 1 part of p-cyclohexylphenol were placed in a reaction vessel equipped with a stirrer and a reflux device.
85 parts of ethyl acetate, 290 parts of ethyl acetate, and 0.2 parts of dibutyltin dilaurate) were reacted at 78 to 80°C for 4 hours, and then ethyl acetate was completely removed by heating at 120°C or lower under reduced pressure. A blocked isocyanate with a melting point of 75-85°C was obtained.

296 parts of this blocked isocyanate, 728 parts of the same polyester resin as in Reference Example 1, 500 parts of titanium oxide (Tiebake R-930 manufactured by Ishihara Sangyo ■), 5 parts of Modern Rho (manufactured by Monsanto), 1,1,3,3-tetrabutyl -1
- 0.5 part of 3-diacetoxydistanoxane was premixed for 5 minutes using a Henschel mixer.

The mixture was melt-blended in an extruder set at 100 to 110°C, cooled, and then heated to 10 to 70°C in an atomizer.
It was ground to a particle size of μ to make a powder coating.

This paint was electrostatically applied to a mild steel plate treated with iron phosphate, and
Baking at 0° C. for 30 minutes gave a robust white coating.

The coating performance is shown in Table 2.

Example 9 A reaction vessel equipped with a stirrer and a reflux device was charged with 111 parts of isophorone diisocyanate, 262 parts of octyl p-hydroxybenzoate, 290 parts of ethyl acetate, and 0.2 parts of dibutyltin dilaurate, and reacted at 78 to 80°C for 4 hours. After that, ethyl acetate was completely removed by heating at 120°C or lower under reduced pressure to obtain a blocked isocyanate with a melting point of 75 to 85°C.

373 parts of this blocked isocyanate, 728 parts of the same polyester resin as in Reference Example 1, 500 parts of titanium oxide (Tybake R-930 manufactured by Ishihara Sangyo ■), Modaflow (
(manufactured by Monsanto) and 0.5 parts of 1,1,3,3-tetrabutyl-1,3-diacetoxydistanoxane were premixed for 5 minutes using a Henschel mixer.

The mixture was melt-blended in an extruder set at 100-110°C, cooled, and then heated in an atomizer to a temperature of 10-70°C.
It was ground to a particle size of μ to make a powder coating.

This paint was electrostatically applied to a mild steel plate treated with iron phosphate, and
A robust white coating was obtained by baking for 309 minutes at 0°C.

The coating performance is shown in Table 2.

Claims (1)

[Claims] 1. Melting point 40°C - CO having at least two hydroxyl groups
A powder coating composition comprising a polyisocyanate flocculated with a phenol having one phenolic hydroxyl group represented by OR1 (R1 represents an alkyl group having 4 to 10 carbon atoms or a cyclohexyl group).