JPH03237173A - One-pack thermosetting resin composition and precoated metal using same - Google Patents

Abstract

PURPOSE:To provide the title composition excellent in bending processability, chemical resistance, etc., containing a blocked product of a poly(>=3)functional polyester polyol and a prepolymer produced by reaction between a specific OH component and an organic diisocyanate. CONSTITUTION:The objective composition suitable as a coating for steel plate such as precoated metal, containing a blocked product of (A) a polyester polyol with three or more functional groups produced by esterification between a dicarboxylic acid, glycol and polyol having at least three OH groups and (B) a NCO group-terminated prepolymer produced by reaction between (1) an organic diisocyanate such as trimethylene diisocyanate and (2) a OH component 100-1000 in number-average molecular weight made up of a low-molecular weight glycol such as ethylene glycol and a macrodiol such as polyester diol.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a one-component thermosetting resin composition that has excellent coating performance and can withstand processing such as bending, and is particularly applicable to pre-coated metals and the like. The present invention relates to a resin composition useful as a paint for steel plates.

Conventional technology In general, pre-coated metal is made by coating a galvanized iron plate or other metal plate with paint beforehand and then molding it into an arbitrary shape for final use.For example, it is used in refrigerators, washing machines, electric stoves, etc. It is used in metal products such as home appliances, vending machines, office equipment, and fixtures including food storage cases.

This kind of pre-coated metal sheet has the advantage of streamlining the painting process, making the quality uniform, and improving the paint quality compared to the post-coating method where the metal sheet is first molded into a complex shape and then painted. It is thought that its use will continue to expand in the future as it has advantages such as saving on consumption.

The paint applied to a pre-coated metal plate is molded into a shape according to the above-mentioned purpose after the paint film is formed, so the paint film is strong enough to withstand forming processes such as bending, roll bottom molding, enhos press, and drawing. It is required to maintain good extensibility and adhesion to metal surfaces. On the other hand, products after Zenigata require performance that suits their respective end uses, such as a high degree of weather resistance in the case of building exterior materials and strong corrosion resistance including processed parts, and home appliances such as refrigerators. Therefore, scratch resistance and stain resistance are required. In addition to these properties, durability such as gloss, water resistance, chemical resistance, and moisture resistance is also required depending on the application.

In applications such as the home appliances mentioned above, aminoalkyd resins, melamine-cured acrylic polyols, or Evoquine resins have traditionally been used. However, these resins have a drawback that the bending processability of the coating film is poor and the coating film cracks when bent at an angle of 90' or more.

A method is also known in which a composition containing a blocked product of bis(isocyanatomethyl)cyclohexane or its adduct and a polyol resin is applied to a metal plate and cured by heating to produce precoated metal. (Unexamined Japanese Patent Publication No. 1983-
No. 89548], the precoated metal obtained by this method did not necessarily satisfy all of the physical properties described above.

Additionally, a method is known in which a composition containing a blocked isocyanate compound blocked with ethyleneimine and a polyol resin is coated on a metal plate and heated and cured to produce a pre-coated metal (Japanese Patent Laid-Open No. 57-1989-1). 10375
The precoated metal obtained by this method also did not satisfy all of the above-mentioned physical properties.

Problems to be Solved by the Invention As mentioned above, it has been a very difficult problem to improve the coating performance while balancing bending workability, stain resistance, and hardness. An object of the present invention is to provide a resin composition that is well-balanced in terms of bending processability, particularly low-temperature processability, chemical resistance fE, and hardness, and provides a coating film that is excellent in other coating properties as well. .

Means for Solving the Problems As a result of intensive research into resin compositions with excellent coating performance, the present inventors developed a prepolymer of a polyester polyol having at least 3 functional groups, a specific OH component, and an organic diisocyanate. Based on this knowledge, we have found that by combining the block compounds of The present invention has now been completed.

That is, the present invention has 1. (1) Number of functional groups is at least 3
Contains a blocked prepolymer having an NCO group at the end obtained by reacting the polyester polyol and (2) an organic diisocyanate with an OH component having a number average molecular weight of 100 to 1000 consisting of a low molecular weight glycol oyohimacrodiol. a one-component thermosetting resin composition, and 2 (1) a polyester polyol having at least 3 functional groups; and (2) an organic diisocyanate;
A one-component thermosetting resin composition containing a blocked prepolymer having an NCO group at the terminal obtained by reaction with a low molecular weight glycol and an OH component having a number average molecular weight of 100 to 1000 consisting of a macrodiol. This invention relates to a precoated metal characterized by being coated on a metal plate and hardened by heating.

The polyester polyol (1) having at least 3 functional groups used in the present invention is a dicarboxylic acid.

It is obtained by esterifying glycols and polyols having at least three OH groups.

Examples of dicarboxylic acids used in the production of polyester polyols include succinic acid, succinic anhydride, adipic acid, azelaic acid, sebacic acid, dodecanoic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid, and dimer acid. Aliphatic, such as phthalic acid, phthalic anhydride, inphthalic acid, isophthalic acid dimethyl ester, terephthalic acid, terephthalic acid dimethyl ester, 2,6-natal dicarphonic acid, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, cyclohexane dicarboxylic acid Aromatic and ring systems such as phonic acid methyl ester, 1,4-chlorohexanedicarphonic acid, methylhexahydrophthalic anhydride, nadic anhydride, methylnadic anhydride, 1tetrachlorophthalic anhydride, tonic acid, etc. I can give you something.

Examples of glycol include ethylene glycol/
Ethylene glycol propylene glycol, l, 3-butylene glycol, 1,4-butylene glycol dipropylene glycol, 1,5-bentanediol, 1,
6-hexanediol, neopentyl glycol opentyl glycol ester, triethylene glycol, 1,9-nonanediol, 3-methyl 1,5-bentanediol, 2,2,4-trimethyl 1,3-bentanediol, 2- Ethyl-1,3 hexane diol, polycaprolactone diol, polypropylene glycol, polytetramethylene ether glycol, polycarponate diol, 2-n-butyl-2-ethyl-1,
Aliphatic ones such as 3-propanediol and 2,2-diethyl-1,3-propanediol, such as cyclohedoxal dimethatol and cyclohedoxedh.sandiol.

Ky7lylene glycol, bis(β-hydroxyethyl)
Terephthalate, 1,4-bis(2-hydroxyethoxy)henzene, hydrogenated bisphenol A, ethylene oxide adduct of bisphenol A. Examples include alicyclic or aromatic compounds such as propylene oxide adducts of bisphenol A.

As the polyol having at least 3 OH groups,
For example, glycerin, trimethylolpropane, trimethylolethane, 1,2.6-triol, pentaerythritol, siglycerin, and ethylene oxide adducts using these polyols as initiators.
Examples include propylene oxide adducts and ε-caprolactone adducts.

The esterification reaction is carried out by distilling off the condensate using a conventional method, but since the product is polyfunctional, there is a risk of gelation if the reaction is allowed to proceed too much, so the acid value is usually 0.1 to 50. It is particularly preferable to stop at a range of 1 to 20.

As a specific production method, for example, dicarboxylic acid is charged in excess of the number of moles of glycol, and the
Condensation water is distilled off after nitrogen gas is blown into the solution at a temperature of 100.degree. C., and the reaction is carried out to a predetermined acid value to obtain a polyester having COOH groups at both ends. Next, at least three O atoms are added to the terminal of this polyester to form an OH group.
An example of this method is to charge a polyol having an H group, distill off condensation water in the same manner, and stop the reaction at an acid value of 50 or less, preferably in the range of 1 to 20.

When dimethyl ester of dicarboxylic acid is used, the number of moles of dicarboxylic acid is greater than the number of moles of glycol, and the condensate is distilled off under the same conditions as above to obtain a polyester having methyl ester groups at both ends. OH
A polyol having a group is charged, and a transesterification reaction is performed under the same conditions as described above to obtain a polyester polyol.

When anhydrous acid is used in combination, dicarboxylic acid is first added in a smaller amount than the number of moles of glycol, and the condensate is distilled off under the same conditions as above to obtain a polyester product having OH groups at both ends, and then dicarboxylic acid is added. An anhydride is added and a ring-opening reaction is performed to obtain a polyester having COOH groups at both ends.

Next, a method can be mentioned in which a polyol having at least three OH groups is charged and a reaction is carried out in the same manner as described above to obtain a polyester polyol.

The polyester polyol used in the present invention has a functional group number of 3 to 7, particularly 3 to 5, and a number average molecular weight of 600 to 4.
000 and a hydroxyl value of 30 to 300 is particularly preferred. If the number of functional groups is less than 3, the hardness of the cured coating may become low and the chemical resistance may deteriorate.

Furthermore, if the number of functional groups exceeds 7, the bending resistance of the coating film may deteriorate. When the number average molecular weight is less than 600, the gloss of the cured coating film becomes poor, and when it exceeds 4000, the viscosity becomes high, which may cause problems in coating workability and may deteriorate stain resistance. If the hydroxyl value is less than 30, the chemical resistance and stain resistance of the cured coating may deteriorate. Furthermore, if the hydroxyl value exceeds 300, the bending resistance of the coating film may deteriorate.

The blocked prepolymer having an NCO group at the terminal (2) used in the present invention is obtained by reacting an organic diiso7anate with an OH component.

Examples of the organic diisocyanate used in the present invention include compounds having at least two NC○ groups, such as trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, and 1,2-propylene diisocyanate. Orthodont, 2,3 ethylene isocyanate, 1.3
-butylene diisocyanate, 2,4.4- or 2,
2. Aliphatic diisocyanates such as 4-1-limethylhexamethylene diisocyanate, dodecamethylene diisocyanate, 2,6-ditucyanatomethylcabroate, such as 1,3-7 clobentanediiso sheer 7
-t, 1.4-cyclohexanediiso/anate, 1.
3-cyclohe bovine diisocyanate.

3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate, 4,4'-methylenebis(cyclohexyl isocyanate), methyl-2,4-
Cyclohexane diisocyanate Methyl-2,6-cyclohexane diisocyanate.

1,2-bis(isocyanatomethyl)cyclohexane, l,4-bis(isocyanatomethyl)cyclohexane, 1,3-bis(isocyanatomethyl)cyclohexane, trans-/chlorohexane-1.4 diisocyanate cycloalkylene diisocyanates, such as ham-phenylene diisocyanate, p-phenylene diisocyanate, 4゜4'-diphenyl diisocyanate, 1.5-naphthalene diisocyanate, 4.4'
-diphenylmethane diisocyanate, 2,4- or 2,6-)lylene diisocyanate, 4,4'-toluidine diiso/anate, dianisidine diisocyanate.

4. Aromatic diisocyanates such as 4'-diphenyl ether diisocyanate, for example ω, ω diisocyanate 1,3-dimethylbenzene, ω.

ω′-diisocyanate 1,4-dimethylbenzene,
Aromatic fats such as ω, ω′-diisocyanate)-1,4-diethylbenzene, α, α, α′, α-tetramethyl metasilylene diisocyanate, α, α, α′, α′-tetramethylvalaxylylene diisocyanate, etc. Examples include group diisocyanates.

When used as a pre-coat metal, weather resistance is required, so among the aforementioned NCO group-containing compounds, hexamethylene diisocyanate, 3-cyanatomethyl-3', 5.5-trimethylcyclohexyl isocyanate), 1.4 -Bis(inocyanatomethyl)cyclohexane, ■, 3-bis(isocyanatomethyl)cyclohexane, 4,4'-methylenebis(cyclohexyl isocyanate), α.

Preferably, incyanate compounds such as α,α,α-tetramethylmethaxylylene diyinyanate are used.

A prepolymer having NCO groups at the terminals can be obtained by reacting a pre-Me incyanate monomer and an OH component in a state in which the incyanate groups are in excess.

The OH component used in the present invention has a molecular weight of 60 to 380,
Preferably a low molecular weight glycol of 60 to 260 and a molecule j
1400-5000. Preferably, the number average molecular weight is reduced to 1 by mixing with a macrodiol of 500 to 4000.
oo-iooo, preferably in the range of 100-800.

If the number average molecular weight of this OH component is less than 100, the hardness will be high, but flexibility will be difficult to achieve, resulting in a brittle coating film. Furthermore, the compatibility with polyester polyols also tends to be poor. On the other hand, if the number average molecular weight is greater than 1000, the flexibility will be excellent, but the chemical resistance will be extremely poor.

Examples of the low molecular weight glycol used in the present invention include ethylene glycol, propylene glycol, 1,
2-butylene glycol, 1,3-butylene glycol, 1,6-hexatanol diethylene glycol,
7 Propylene glycol inopentyl glycol, inobentyl glycol hydroxy bivalate, triethylene glycol, hydrogenated bisphenol A, xylylene glycol, 1,4-butylene glycol, ■, 9
-nonanediol, 3-methyl-1,5-bentanediol, 2,2.4-trimethylpentan-1,3-/ol, spiroglycol, oxane glycol propylene oxide adduct of bisphenol A, ethylene oxide of bisphenol A Adduct Ncrohe Bovine Sandimethol, Bisg β-Hydroquine Ethyl) Terephthalate, 2-Ethyl-1,3 to Bovine Sandiol + 2 n-Butyl-2-ethyl 1,3-Propanediol, 2,2-
Diethyl-1゜3-propanediol, 1,4-bis(
Examples include 2-hydroxyethoxy)benzene, 1,5-bentanediol, 2-methyl-1,3-butanediol, dibromoneopentyl glycol, and the like.

These glycols may be used alone or in combination.

The macrodiol, which is the other component in the OH component used in the present invention, is a macrodiol consisting of a dibasic acid with a terminal OH group and a glycol. Examples include polyether diols such as lactone diol, polytetramethylene ether glycol, propylene oxide adducts and ethylene oxide adducts of low molecular weight glycols, polycarbonate diols, polybutane enols, and polyolefin diols, especially those with ester bonds. , a macrodiol having a carbonate bond or an ether bond is preferred.

These macrodiols may be used alone or in combination.

The prepolymer generally has an equivalent ratio of NCO groups to 10H groups of about 1.5 to 12. Preferably about 2-7, usually 40-7
After carrying out the reaction at 140'C, preferably from 70 to 100'C, unreacted incyanate monomers can be removed, if necessary, by conventional thin film distillation or extraction.

In this reaction, an organic metal catalyst such as a tin-based, lead-based, zinc-based, or iron-based catalyst may be used.

The blocked product of the prepolymer described above can be obtained by reacting it with a blocking agent by a known method. The blocking agents used in this reaction include blocking agents known to be used to block incyanates, such as phenol-based, lactam-based, active methylene-based, alcohol-based, mercaptan-based, and acid amide-based blocking agents. , imide-based, amine-based, imidazole-based, urea-based, carbamate-based, imine-based, oxime-based, or sulfite-based blocking agents can be used, but especially phenol-based, oxime-based, lactam-based, Imine-based and nofloc agents are advantageously used. Specific examples of blocking agents include the following.

Phenolic blocking agents: phenol, cresol, beef sire, nitrophenol, chlorophenol, ethylphenol.

p-hydroxydiphenyl, tert-butylphenol, 0-isopropylphenol, o-5ec-butylphenol, p-nonylphenol, p-tert-
Octylphenol, hydroxybenzoic acid, hydroxybenzoic acid ester, etc.

Lactam-based blocking agents: ε-caprolactam, δ-valerolactam, γ-butyrolactam, β-propiolactam, etc.

Active methylene blocking agents: diethyl malonate, dimethyl malonate, ethyl acetoacetate, methyl acetoacetate, acetylacetone, etc.

Alcohol-based blocking agent: methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, imbutyl alcohol, tert-butyl alcohol, n-
Amyl alcohol, tert-amyl alcohol urauryl alcohol, ethylene glyco-monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether.

Glycolic acid esters such as diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol monomethyl ether, benzyl alcohol, methoxymethanol, glycolic acid, methyl glycolate, ethyl glycolate, butyl glycolate, lactic acid, methyl lactate, ethyl lactate, butyl lactate Lactic acid ester of Nato, methylol urea, methylol melamine, diacetone alcohol ethylene chlorohydrin ethylene bromohydrin, 1,3-fuchloro-2-propatol, ω-hydroperfluoro alcohol, acetocyanhydrin, etc.

Mercaptan blocking agent butyl mercaptan, hexyl mercaptan tert-
Butyl mercaptan, tert-dotesyl mercaptan, 2-mercaptobenzothiazole, thiophyl, methylthiophyl, ethylthiophenol, etc.

Acid amide blocking agent acetanilide, acedoanidicite, acetotoluide,
Acrylamide, methacrylamide, acetamide, stearamide, benzamide, etc.

Imide blocking agents: succinimide, phthalic imide, maleic imide, etc.

Amine-based blocked products diphenylamine phenylnaphthylamine, quinolizine, N-phenylquinlysine, carbazole.

Aniline naphthylamine, butylamine, dibutylamine, butylphenylamine, etc.

Imidazole blocking agent.

imidazole, 2-ethylimidazole, etc.

Urea-based blocking agent: urea, thiourea, ethylene urea, ethylene thiourea Ll,
3-diphenylurea etc.

Carbamate-based blocking agents: such as phenyl N-phenylcarbamate and 2-oxal sacilidone.

Imine blocking agent・ Ethyleneimine, propyleneimine, etc.

Oxime-based blocking agents such as formamide oxime, acetaldoxime, acetoxime methyl ethyl ketoxime, diacetyl monooxime, benzophenone oxime, cyclohexanone oxime, etc.

Sulfite-based blocking agent Bisulfite sorter, bisulfite power r), etc.

As a specific method for the reaction between the prepolymer and the blocking agent mentioned above, for example, the prepolymer and the blocking agent are reacted with N.
Equivalent ratio of CO groups/active hydrogen groups in blocking agent - approximately 0.9
-1.0, preferably about 095-1.0, the isocyanate monomer and the blocking agent are reacted with NC○ group/
Equivalent ratio of active hydrogen groups in blocking agent = approximately 1.1 to 3.0
, preferably about 1.2 to 2.0, and then reacting therewith an OH component having a number average molecular weight of 100 to 1000, which is used in the production of Brebommer.

Each of the above reactions was carried out in a solvent that does not have active hydrogen groups (e.g. aromatic systems such as benzene, toluene, xylene, etc.,
00, petroleum solvents such as Tsurpetz-200, and esters such as ethyl acetate and butyl acetate.

For example, a ketone type such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, etc., an ether type such as tetrahydrofuran, etc.) or a known method in the absence of such a solvent. In the reaction, known catalysts such as tertiary amines and organic metals may be used.

The one-component thermosetting resin composition of the present invention is a composition containing the aforementioned polyol (1) and blocked product (2).

The blending ratio of polyol and blocked product is OH group/regenerated N
The equivalent ratio of CO groups is about 1/2 to 2/l, especially about 110.8
~1/1.2 is preferred.

The composition of the present invention can be used as it is as a clear paint or adhesive, but in addition to the above-mentioned podiols and blocked products, ester-based compounds such as ethyl acetate, butyl acetate, methyl acetoacetate, 2-ethquinethyl acetate, etc. , aromatic systems such as xylene, toluene, ketone systems such as methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone, ether systems such as diethylene glycol dimethyl ether, ゛/ruhey7 10
0゜Origin solvent such as petroleum-based solvent such as Tsurugenoso 200,
For example, colored pigments, extender pigments, silicone-based, amine-based 1
Polyether-based, polyester-based, Himanura-based base wax-based, hentonite-based dispersants, if4 foaming agents,
Leveling agents, thixotropic agents, stabilizers such as hensitriazoles, hinted amines, and hinted phenols,
A tin-based, lead-based, zinc-based, or iron-based reaction catalyst may be added as necessary.

The one-component thermosetting resin composition of the present invention thus obtained is coated on a substrate and then heated to dissociate the blocking agent contained in the pro-chloride and regenerate the NCO groups. The regenerated NCO groups react with the OH groups in the polyol to provide a cured coating.

The resin composition of the present invention is used as a paint, an adhesive, etc., and is particularly advantageously used in the production of precoated metal.

The metal sheets used in the production of pre-coated metal are usually
Any metal that can be used as a pre-coated metal may be used, such as cold-rolled steel sheets, galvanized steel sheets, and double-alloyed galvanized steel sheets.

Tin-plated steel sheet, chrome-plated steel sheet, aluminum-plated steel sheet, lead-plated steel sheet, 2. Kel-plated steel sheet.

Examples include aluminum plates, titanium plates, and stainless steel plates. The resin composition of the present invention can be applied directly or after being subjected to a usual pre-painting treatment.

Moreover, in any case, the resin composition of the present invention can be applied after or without drying the brimer paint after it has been applied and dried, if necessary. Pre-painting treatments include chromate chemical conversion treatment, phosphate chemical conversion treatment, and composite oxide film treatment. Chromate chemical treatment includes electrolytic chromate, coating type chromate, and reactive chromate treatment; phosphate chemical treatment includes zinc phosphate treatment and iron phosphate treatment; and composite oxide film treatment includes Ni, Kel and cobalt. There is processing.

As the brimer paint, commonly used paints such as epoxy resin type and polymeric polyester type can be used.

The shape of the metal plate may be, for example, flat or cylindrical. The resin composition of the present invention is applied to this metal plate. The amount of coating is not limited and can be determined freely, but it is preferably an amount that provides a dry film thickness of 10 to 30 microns.

An example of a means of application is a spray gun.

Examples include roll coater and flow coater.

Next, the coated metal plate is heated and hardened.

Although the heating temperature varies depending on the type of blocking agent, it is preferably about 150 to 350'C, and the heating time is preferably about 20 to 120 seconds. This heating operation dissociates the blocking agent contained in the blocked product and regenerates the NCO groups, and the regenerated NCO groups react with the OH groups in the polyol to cause crosslinking, resulting in a tough coating film.

Effects of the Invention The coating film obtained by curing the one-component thermosetting resin composition of the present invention shows no discoloration or thermal deterioration due to heating operations. Moreover, it has high hardness, excellent chemical resistance, bending workability, and especially low-temperature workability. In particular, when the composition of the present invention is used to produce precoated metal, a plate steel sheet of good quality can be obtained, so it can be advantageously used for home appliances and the like.

Hereinafter, the present invention will be explained more specifically using reference examples and examples. In the examples, parts and % indicate parts by weight and % by weight, respectively.

Reference Example 1 for Production of Polyol 399°7 parts of 3-methyl-1,5-bentanediol (
3,38 moles), 335.5 parts of phthalic anhydride (2,2
7 mol) and 0.1 part of dibutyltin dilaurate were placed in a reaction vessel, heated to 220°C, nitrogen gas was blown in, and the reaction was carried out while distilling off the condensed water produced. When the acid value reached 10.0, 2237 parts of phthalic anhydride (
1,51 mol) and reacted for 1 hour from the time when the reaction temperature reached 170'C to form a terminal C0 with an acid value of 107.0.
An esterified product having an OH group was obtained. Further, 152.7 parts (1.14 moles) of trimethylolpropane (hereinafter referred to as TMP) and 0.1 part of dibutyltin dilaurate were charged, and the reaction was similarly carried out while distilling off the water of condensation to obtain an acid value of 60. A polyester polyol having a hydroxyl value of 726 was obtained. This polyol was dissolved in cyclohexanone to form a solution with a solid content of 50%.

Reference Example 2 259.3 parts (180 mol) of cyclohexanone methanol and 4621 parts (2,68 mol) of 1,4-cyclohexanedicarboxylic acid are charged into a reaction vessel, heated to 220'C and nitrogen gas blown into the resulting condensed water. The reaction was carried out while distilling off , and when the acid value reached 155.0, 60.0 parts (0.45 mol) of TMP was added. The reaction was carried out while condensation water was distilled off, and when the acid value reached 100.0, BA3G glycol (Nippon Nyukazai Co., Ltd.) glycol, ethylene oxide adduct of bisphenol A (1 molecular weight -354.0) 318.2 parts (0 , 9 mol) and 0.1 part of dibutyltin dilaurate were charged and reacted while distilling off the condensation water produced in the same manner to obtain a polyester polyol having an acid value of 32 and a hydroxyl value of 1048. This polyol was dissolved in cyclohexanone to form a solution with a solid content of 50%.

Reference Example 3 34.1 parts (0.55 mol) of ethylene glycol and 5927 parts (1.05 mol) of timer acid were placed in a reaction vessel, heated to 200'C, nitrogen gas was blown in, and the condensed water produced was distilled off. The reaction was started, and when the acid value reached 983, 70.5 parts (0.53 moles) of TMP and 2963 parts (0.52 moles) of timer acid were added. The reaction was carried out while distilling off the water of condensation, and when the acid value reached 510, 71.4 parts (1.15 mol) of ethylene glycol and 1 part of dibutyltin dilaure H) were added, and the water of condensation produced in the same manner was added. The reaction was carried out while distilling off, and the acid value was 09. A polyester polyol with a hydroxyl value of 131.4 was obtained. This polyol was dissolved in cyclohexanone to form a solution with a solid content of 50%.

Reference example 4 313.4 parts (1,89 mol) of isophthalic acid, l.

6- To a reaction vessel, 341.1 parts (2.89 mol) of bovine diol and 0.1 part of dibutyltin dilaurate were charged, heated to 220'C, nitrogen gas was blown in, and the condensed water produced was distilled off. When the acid value reached 3.0, 279.4 parts of phthalic anhydride (1,89
Prepare mole). After the reaction temperature reached 170°C, the reaction was carried out for 1 hour to obtain an esterified product having an acid value of 127.0 and a terminal C0OH group. In addition to this, TMP63.6
(0.47 mol) of 1,6-hexanediol and 113.7 parts (0.96 mol) of dibutyltin dilaurate were reacted while distilling off the water of condensation, and when the acid value reached 65.0, .1 part was charged and reacted in the same manner while distilling off the condensed water produced to give an acid value of 5.5° and a hydroxyl value of 8.
A polyester polyol of 2.2 was obtained. This polyol was dissolved in cyclohexanone to form a solution with a solid content of 50%.

Reference Example 5 412° 4 parts of 3-methyl-1,5-bentanediol (
349 mol), 2074 parts (1.40 mol) of phthalic anhydride, and 0.12 parts of dibutyltin dilaurate were placed in a reaction vessel, heated to 220°C, nitrogen gas blown in, and the reaction was carried out while distilling off the condensed water produced. and the acid value is 1
When it reached 9.0, 414.7 parts of phthalic anhydride (
280 mol) and reacted for 1 hour from the time when the reaction temperature reached 170°C.
) (An esterified product having a group was obtained. This was further treated with TMP.
283.2 (2.11 mol) and 0.24 parts of dibutyltin dilaure I- were charged and reacted in the same manner while distilling off the water of condensation to give an acid value of 9.8. A polyester polyol with a hydroxyl value of 103.0 was obtained. This polyol was dissolved in cyclohexanone to form a solution with a solid content of 40%.

Reference example 6 22-7 ethyl-1,3-propanediol 667.6
parts (505 mol) and 1180°9 parts of succinic acid (10,
00 mol) was charged into a reaction vessel, heated to 200°C, nitrogen gas was blown in, and the resulting condensation water was distilled off before reacting to obtain an esterified product having an acid value of 3460 and a terminal COOH group.

337.1 parts (2.51 mol) of TMP was added to this,
Similarly, the reaction was carried out without distilling off the water of condensation, and when the acid value reached 1366, 6676 parts (505 mol) of 2,2-7ethyl 1,3-propanediol and 010 parts of 7-butyltin/laurate were added, and the condensation was carried out. The reaction was carried out without distilling off the water to obtain a polyester polyol having an acid value of 42 and a hydroxyl value of 1,669. This polyol was dissolved in 7-chlorohexanone to form a solution with a solid content of 50%.

Table 1 shows the properties of the polyester polyols obtained in Reference Examples 1 to 6 and the solutions obtained by dissolving them in cyclohexanone.

Reference example 7 for production of blocked product 1.3-bis(isocyanatomethyl)cyclohexane 160. C1, 240.0 parts of cyclohexanone and 1.
0.202 parts of 1,3.3-tetra-n-butyl-1,3 diacetoxydistanoxane is charged into a reaction vessel, and the temperature is raised to 75 to 80'C under a nitrogen gas atmosphere. Next, the number average molecular weight was set to 380.
) 66.4 parts, 664 parts of Kurabol P-1010 (manufactured by Kuraray Co., Ltd., poly-3-methyl-1,5-bentanediol adipate, min. 1!-1000) and 29.6 parts of 1,4-butanediol. Cyclohexanone 162.4
3,248 parts of the solution] was gradually added dropwise so that the internal temperature did not exceed 80°C.

After the dropwise addition was completed, the temperature was maintained at 75-80°C for 2 hours, and then 69.0 parts of methyl ethyl ketoxime was gradually added. After the addition is complete, the reaction is allowed to proceed for 1 hour at 75-80"C. Thus, the regenerated isoneanate group content is -4.08%, the solid content is 50%,
A foam viscosity (25°C) I-J pro-carbide solution was obtained.

Reference Examples 8 to 16 Reactions were carried out in the same manner as in Reference Example 7 except that the amounts of raw materials charged were changed as shown in Table 2 to obtain each blocked product solution.

Reference Example 17 Polyethylene succinate with a number average molecular weight of 234.4 as the OH component (acid value obtained by esterifying 17.0 mol of succinic acid and 37.4 mol of ethylene glycol by a known reaction method = 0.3. hydroxyl group) Polyester having a value of -478.3) was reacted in the same manner as in Reference Example 7 to obtain a block compound solution.

Reference Example 18 Using BA3G glycol with a molecular weight of 354.0 as the OH component, a reaction was carried out in the same manner as in Reference Example 7 to obtain a fluoride compound solution.

Table 2 shows the properties of the block compound solutions obtained in Reference Examples 7 to 18 and the amount of raw materials required to obtain 800 parts of the block compound solutions in parts.

(Left below) Example 1 Polyester polyol solution obtained in Reference Example 1 39
．． 8 parts and 26.5 parts of the block compound of Reference Example 7 (
NCO10H equivalent ratio -1,0), PWC (pigment
Titanium oxide (Tie Bake R820; Ishiya Sangyo Co., Ltd.) 3 to give a weight concentration of 50%
3. Prepare 1 part. Furthermore, 0.023 part of 1,1.3.3-tetra-n-butyl-1<3>-diacetoxydistanoxane was added as a catalyst, and the mixture was thoroughly kneaded with a paint conditioner to obtain a white enamel solution. This solution is 0
, 6 After applying electrolytic chromate treatment to an electrolytic galvanized copper plate with a thickness of a+a+, an epoxy resin-based primer paint was applied to a dry film thickness of 5 μm, and a bar coater was applied to the baked product to a dry film thickness of 20 μm. Painted with 26
A glossy white coating film was obtained by baking for 60 seconds in an atmosphere of 0°C. Table 3 shows the formulation and coating performance of the white enamel.

Examples 2 to 10 Using the blocked products of Reference Examples 7 to 14, the baking conditions were as in Example 1 for a formulation in which the total amount of white enamel melting with PWC = 50% was 100 parts as shown in Table 3. It was conducted under similar conditions.

Comparative Examples 1 to 4 Using the block compounds of Reference Examples 15 to 18, Examples 2 to 4
The test was carried out under the same conditions as in 10.

(Margin below) Evaluation method old pencil hardness Scratch trace method JIS method Bending resistance old drama contamination J Is-to-5400 method Sweep the paint film with a pencil according to the Wipe the inside surface with a degreased surface to remove any scratches. It is expressed by the hardness of a pencil that does not leave marks. vinegar.

J Is-to-5400 method evening.

Insert an iron plate with the same thickness as the test piece. So, 50kgG with hand press /am” pressure to 180 degrees. Fold, folded part 30x Observe with a magnifying glass and crack The minimum size of iron plate that does not fit Expressed in number.

Draw lines on the painted surface with magic ink After leaving it for 24 hours, wipe it with absorbent cotton. Wipe it off with ethanol, Evaluate what follows the line.

○: A faint mark remains.

△・ Some traces remain.

×: A mark remains clearly.

C. Chemical resistance Acid resistance Seal the cut surface of the test piece with paraffin wax and immerse it in a 5% HC solution for 24 hours, then take it out and visually evaluate the presence or absence of abnormalities on the coating surface.

The cut surface of the alkali resistance test piece is sealed with paraffin wax, immersed in a 5% KOH solution for 24 hours, and then taken out and visually evaluated for any abnormalities on the surface of the coating.

Claims (1)

[Claims] 1. Obtained by the reaction of (1) a polyester polyol having at least 3 functional groups and (2) an organic diisocyanate with an OH component having a number average molecular weight of 100 to 1000 and consisting of a low molecular weight glycol and a macrodiol. A one-component thermosetting resin composition containing a blocked prepolymer having an NCO group at the end. 2. The composition according to claim 1, wherein the low molecular weight glycol has a molecular weight of 60 to 380, and the macrodiol has a molecular weight of 400 to 5,000. 3. An NCO group is added to the terminal obtained by reacting (1) a polyester polyol having at least 3 functional groups and (2) an organic diisocyanate with an OH component having a number average molecular weight of 100 to 1000 consisting of a low molecular weight glycol and a macrodiol. 1. A precoated metal, characterized in that a one-component thermosetting resin composition containing a blocked prepolymer is coated on a metal plate and cured by heating.