JP2023040673A - Blocked polyisocyanate composition, coating composition and coating layer - Google Patents

Abstract

To provide a blocked polyisocyanate composition that can form a coating layer having excellent water resistance, weather resistance, toughness, hardness and impact resistance and can also prepare a coating composition having a long pot life for forming the coating layer.SOLUTION: A blocked polyisocyanate composition contains a blocked polyisocyanate obtained from (A) a diisocyanate, at least one polyol selected from the group consisting of (B1) a polyether-based polyol having an oxypropylene group with a number average molecular weight of 400 or more and 10000 or less and (B2) a polyester-based polyol derived from an alcohol with a valence of two or more and three or less and ε-caprolactone with a number average molecular weight of 250 or more and 5000 or less, and (C) a blocker, the composition having an allophanate group, an isocyanurate group and a urethane group. When the mol of the isocyanurate group is E and the mol of the urethane group before blocking is F, F/E is 0.10 or more and 11.00 or less.SELECTED DRAWING: None

Description

The present invention relates to blocked polyisocyanate compositions, coating compositions and coating films.

Coating compositions using polyisocyanate compositions are widely used as coatings for construction, automobiles, plastics, information appliances, etc., because of their excellent appearance, weather resistance and durability. Above all, in applications such as automobiles and construction applications, which require high-quality appearance and excellent weather resistance and durability, a two-component polyurethane that can form a dense crosslinked coating film and has a good finished appearance. Highly rated paint.

In addition to the above properties, there is a demand for a coating composition that has good water resistance, extensibility, bendability, and adhesion to substrates for automotive applications, building applications, and the like. Conventionally, when preparing such a coating composition, polyols such as acrylic polyols and polyester polyols are used as the main component, and hexamethylene diisocyanate (hereinafter sometimes abbreviated as "HDI") as the curing component. A method of imparting high hardness to a coating film by using a composition obtained by isocyanurating a diisocyanate and a polyhydric alcohol as raw materials has been used. However, since the isocyanurated composition hardens the coating film, the flexibility thereof is lowered, and the coating film cannot follow expansion and contraction due to temperature changes, and the coating film may crack. Techniques for imparting extensibility to coating films in order to solve this problem are disclosed in, for example, Patent Documents 1, 2 and 3. Patent Document 1 discloses a reaction product of an aliphatic diisocyanate or an alicyclic diisocyanate and a polyether polyol having an oxypropylene group. Patent Document 2 discloses a polyisocyanate composition having allophanate groups using a polyester polyol derived from ε-caprolactone. Patent Document 3 discloses a reaction product of an aliphatic diisocyanate or an alicyclic diisocyanate and a polycaprolactone polyol.

On the other hand, in Patent Document 4, as a method for providing a polyisocyanate composition having excellent water resistance, weather resistance and spreadability when formed into a coating film, and a coating composition and a coating film using the polyisocyanate composition, A group consisting of a polyether polyol having an oxypropylene group and having a number average molecular weight of 400 or more and 10000 or less and a polyester polyol having a number average molecular weight of 250 or more and 4000 or less derived from a dihydric to trihydric alcohol and ε-caprolactone. Disclosed is a method of using a polyisocyanate composition containing allophanate groups, isocyanurate groups and urethane groups, comprising a polyisocyanate obtained from at least one polyol selected from:
Patent Document 5 discloses a block polyisocyanate composition which has good compatibility with various main agents, is water-dispersible, and exhibits excellent water resistance and curability when formed into a coating film.

Japanese Patent No. 5388405 JP 2011-105886 A JP-A-61-028518 JP 2020-147737 A JP 2020-143231 A

With the techniques disclosed in Patent Documents 1, 2 and 3, the resulting coating film may lack water resistance and weather resistance.
In the technique disclosed in Patent Document 4, the viscosity of the coating composition obtained by mixing the polyisocyanate composition and various main agents is large, and there is a need to further extend the pot life of the coating composition. . Furthermore, the coating film obtained from the coating composition may exhibit insufficient performance when extensibility and strength upon extension are required. Furthermore, the impact resistance as a coating film is not clear.
In the technique disclosed in Patent Document 5, the coating film has water resistance, but the toughness, impact resistance, and weather resistance of the coating film are not clear.

The present invention has been made in view of the above circumstances, and is capable of forming a coating film having excellent water resistance, weather resistance, toughness, hardness and impact resistance. Provided are a blocked polyisocyanate composition from which a coating composition that lasts for a long time can be prepared, and a coating composition and a coating film using the blocked polyisocyanate composition.

That is, the present invention includes the following aspects.
The blocked polyisocyanate composition according to the first aspect of the present invention comprises (A) at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates, and (B1) a number average molecular weight of 400 to 10,000. and (B2) at least one selected from the group consisting of polyester polyols having a number average molecular weight of 250 or more and 5000 or less derived from dihydric to trihydric alcohol and ε-caprolactone. and a blocked polyisocyanate obtained from (C) a blocking agent, having an allophanate group, an isocyanurate group and a urethane group, wherein the number of moles of the isocyanurate group is E, and the urethane group before blocking The ratio F/E of F to E is 0.10 or more and 11.00 or less, where F is the number of moles of
In the blocked polyisocyanate composition according to the first aspect, the ratio D/E of D to E is 0.01 or more and 3.00 or less, where D is the number of moles of the allophanate groups. good too.
In the blocked polyisocyanate composition according to the first aspect, the ratio F/(D+F) of F to the sum of D and F may be 0.35 or more and 0.99 or less.

A coating composition according to a second aspect of the present invention includes a polyol having a hydroxyl value of 5 mgKOH/g or more and 200 mgKOH/g or less, and the blocked polyisocyanate composition according to the first aspect.
The coating composition according to the second aspect may be used for coating metals or plastics.
The coating composition according to the second aspect may be used as a coating for architectural structures, automobile bodies, metal parts for automobiles, plastic parts for automobiles, metal parts for home information appliances, or plastic parts for information home appliances.

The coating film according to the third aspect of the present invention is obtained by curing the coating composition according to the second aspect.

The blocked polyisocyanate composition of the above aspect provides a coating film excellent in water resistance, weather resistance, toughness, hardness and impact resistance, and a coating composition having a long pot life for forming the coating film. can. The coating composition of the above aspect contains the blocked polyisocyanate composition and can provide a coating film excellent in water resistance, weather resistance, toughness, hardness and impact resistance. The coating film of the above aspect is obtained by curing the coating composition and is excellent in water resistance, weather resistance, toughness, hardness and impact resistance.

EMBODIMENT OF THE INVENTION Hereinafter, the form (henceforth "this embodiment") for implementing this invention is demonstrated in detail. The following embodiments are examples for explaining the present invention, and are not intended to limit the present invention to the following contents. Various modifications are possible for the present invention without departing from the gist thereof.

As used herein, "polyol" means a compound having two or more hydroxy groups (--OH) in one molecule.
In this specification, "polyisocyanate" means a reactant in which a plurality of monomeric compounds having two or more isocyanate groups (--NCO) are bonded.
In this specification, unless otherwise specified, "(meth)acryl" includes methacryl and acryl, and "(meth)acrylate" includes methacrylate and acrylate.

<<Blocked polyisocyanate composition>>
The blocked polyisocyanate composition of this embodiment contains a blocked polyisocyanate obtained from (A) a diisocyanate, (B) a polyol, and (C) a blocking agent.
The (A) diisocyanate is at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates.
The (B) polyol includes (B1) a polyether-based polyol having an oxypropylene group having a number average molecular weight of 400 or more and 10000 or less and (B2) a number average number derived from a divalent or more and a trihydric alcohol and ε-caprolactone It is at least one polyol selected from the group consisting of polyester polyols having a molecular weight of 250 or more and 5,000 or less.

In addition, the blocked polyisocyanate composition of the present embodiment has allophanate groups, isocyanurate groups and urethane groups. In the blocked polyisocyanate composition of the present embodiment, all of these functional groups may be contained in one blocked polyisocyanate, or the blocked polyisocyanate composition of the present embodiment may contain It can also be a mixture of blocked polyisocyanates containing at least one.

In the blocked polyisocyanate composition of the present embodiment, when E is the number of moles of isocyanurate groups and F is the number of moles of the urethane groups before blocking, the ratio of F to E is F/E (in this specification, sometimes simply referred to as "F/E") is 0.10 or more and 11.00 or less, preferably 0.15 or more and 7.00 or less, and 0.25 or more and 2.50 or less is more preferable.
By using a blocked polyisocyanate composition having an F/E in such a range, a coating composition having a long pot life can be obtained, and a coating excellent in water resistance, weather resistance, toughness, hardness and impact resistance can be obtained. A membrane is obtained.
F/E (in other words, E and F) is, for example, by adjusting various conditions such as the amounts of (A) diisocyanate, (B) polyol, and (C) blocking agent when obtaining the blocked polyisocyanate. , adjustable.

More specifically, E increases the number of isocyanurate groups contained in one molecule of (A′) polyisocyanate obtained by converting (A) diisocyanate to isocyanurate using a catalyst, as described later. so you can make it bigger. As will be described later, F can be increased by increasing the reaction ratio when (A') polyisocyanate and (B) polyol are reacted. D is a block polyisocyanate obtained by allophanatizing an isocyanate having a urethane group, which is obtained by reacting (A′) polyisocyanate and (B) polyol, as described later. The size can be increased by increasing the number of allophanate groups contained in one molecule.

In the blocked polyisocyanate composition of the present embodiment, when the number of moles of the allophanate groups is D, the ratio D/E of the D to the E (in this specification, simply referred to as "D/E" is preferably 0.01 or more and 3.00 or less, more preferably 0.01 or more and 2.00 or less, and even more preferably 0.01 or more and 0.90 or less.
A blocked polyisocyanate composition in which D/E is in such a range has a longer usable life of the coating composition, and the coating film has higher water resistance, weather resistance, toughness, hardness and impact resistance. better in terms of
D/E (in other words, D and E) is determined by adjusting various conditions such as the amounts of (A) diisocyanate, (B) polyol, and (C) blocking agent when obtaining the blocked polyisocyanate. , adjustable.

In the blocked polyisocyanate composition of the present embodiment, the ratio F/(D+F) of F to the sum of D and F (herein sometimes simply referred to as "F/(D+F)") is , is preferably from 0.35 to 0.99, more preferably from 0.50 to 0.99, and even more preferably from 0.70 to 0.99.
A blocked polyisocyanate composition in which F/(D+F) is in such a range is advantageous in that the usable life of the coating composition is extended, and the water resistance, weather resistance, toughness, hardness and impact resistance of the coating film are improved. The higher, the better.
F/(D+F) (in other words, D and F) adjusts various conditions such as the amounts of (A) diisocyanate, (B) polyol, and (C) blocking agent when obtaining the blocked polyisocyanate. That way you can adjust.

Each molar ratio of the allophanate group, isocyanurate group and urethane group can be determined by ¹³ C-NMR measurement as described in Examples below.

By using the blocked polyisocyanate composition of the present embodiment having the above configuration, a coating film having excellent water resistance, weather resistance, toughness, hardness and impact resistance, and a pot life for forming the coating film A long coating composition is obtained.
Next, each component of the blocked polyisocyanate composition of the present embodiment will be described in detail below.

<(A) diisocyanate>
(A) Diisocyanate is at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates.
An aliphatic diisocyanate is a compound having a saturated aliphatic group in its molecule. On the other hand, an alicyclic diisocyanate is a compound having a cyclic aliphatic group in its molecule. The use of an aliphatic diisocyanate is preferred because the resulting blocked polyisocyanate composition has a low viscosity.
Examples of aliphatic diisocyanates include 1,4-diisocyanatobutane, 1,5-diisocyanatopentane, 1,6-diisocyanatohexane (hexamethylene diisocyanate, HDI), 1,6-diisocyanato-2,2 ,4-trimethylhexane, methyl 2,6-diisocyanatohexanoate (lysine diisocyanate) and the like.
Examples of alicyclic diisocyanates include 5-isocyanato-1-isocyanatomethyl-1,3,3-trimethylcyclohexane (isophorone diisocyanate; hereinafter sometimes abbreviated as "IPDI"), 1,3-bis ( isocyanatomethyl)cyclohexane (hydrogenated xylylene diisocyanate), bis(4-isocyanatocyclohexyl)methane (hydrogenated diphenylmethane diisocyanate), 1,4-diisocyanatocyclohexane and the like.
Hereinafter, aliphatic diisocyanates and alicyclic diisocyanates may be collectively referred to as "diisocyanates."

(A) Diisocyanate may be used singly or in combination of two or more.

Among them, (A) diisocyanate is preferably HDI, IPDI, hydrogenated xylylene diisocyanate or hydrogenated diphenylmethane diisocyanate because of its industrial availability. HDI is particularly preferred because of its excellent weather resistance and flexibility of the coating film.

<(B) Polyol>
(B) The polyol includes (B1) a polyether-based polyol having an oxypropylene group having a number average molecular weight of 400 or more and 10000 or less, and (B2) a number average number derived from a divalent or more and a trihydric alcohol and ε-caprolactone. It is at least one polyol selected from the group consisting of a polyester polyol having a molecular weight of 250 or more and 5000 or less. The polyether-based polyol having an oxypropylene group as used herein is a polyether polyol having an oxypropylene group in the molecular chain. In this case, the oxyalkylene repeating unit may contain other oxyalkylene groups such as oxyethylene, oxytetramethylene, oxycyclohexyl or oxystyrene groups.

The content of the oxypropylene group having a side chain is preferably 60 mol% or more, more preferably 70 mol% or more, and even more preferably 80 mol% or more, based on the total molar amount of the oxyalkylene repeating units.

(B1) The upper limit of the number average molecular weight of the polyether-based polyol is 10,000, preferably 7,000, and more preferably 3,500. On the other hand, the lower limit of the number average molecular weight is 400, preferably 500. (B1) The polyether-based polyol has a number average molecular weight of 400 to 10,000, preferably 500 to 7,000, and more preferably 500 to 3,500.
When the number average molecular weight of (B1) the polyether-based polyol is within the above range, the flexibility of the coating film becomes more sufficient, and the curability of the coating film becomes more sufficient.
(B1) The number average molecular weight of the polyether-based polyol can be obtained by gel permeation chromatography (hereinafter sometimes abbreviated as “GPC”) measurement.

(B1) Specific examples of the polyether-based polyol include, for example, polypropylene glycol or triol, so-called Pluronic (registered trademark) type polypropylene glycol or triol obtained by addition-polymerizing ethylene oxide at the end of polypropylene glycol, polyoxypropylene polyoxy ethylene copolymer diols or triols, polyoxypropylene polyoxyethylene block polymer diols or triols, polytetramethylene glycol or triols, polyoxydimethylpropylene polyoxybutylene copolymer diols or triols, polyoxydimethylpropylene polyoxybutylene block polymer diols or triols, polyoxycyclohexanediol and the like. Among them, the (B1) polyether-based polyol has excellent solubility in a low-polarity organic solvent, so-called Pluronic (registered trademark) obtained by adding ethylene oxide to the end of polypropylene glycol or triol, or polypropylene glycol. Polypropylene glycols or triols of the type are preferred. Among them, as the polyether-based polyol (B1), a so-called Pluronic (registered trademark) type polypropylene glycol or triol obtained by addition-polymerizing ethylene oxide at the end of polypropylene glycol is more preferable because of its excellent reactivity.

(B1) The polyether-based polyol may be used alone or in combination of two or more.

(B1) Commercially available polyether-based polyols include, for example, EXCENOL 840 (trade name, AGC Co., Ltd., polypropylene triol, number average molecular weight: 6500), EXCENOL 510 (trade name, AGC Co., Ltd., polypropylene glycol, number average molecular weight 4000), EXCENOL 230 (trade name, AGC Co., Ltd., polypropylene triol, number average molecular weight 3000), EXCENOL 2020 (trade name, AGC Co., Ltd., polypropylene glycol, number average molecular weight 2000), EXCENOL 1030 (trade name) , AGC Co., Ltd., polypropylene triol, number average molecular weight 1000), EXCENOL 1020 (trade name, AGC Co., Ltd., polypropylene glycol, number average molecular weight 1000), EXCENOL 3020 (trade name, AGC Co., Ltd., polypropylene glycol, number average molecular weight 3200), Preminol 7012 (trade name, manufactured by AGC Co., Ltd., polypropylene triol, number average molecular weight 10000), PTG1000SN (trade name, manufactured by Hodogaya Chemical Co., Ltd., polytetramethylene glycol, number average molecular weight 1000), and the like. be done.

(B1) As a method for producing a polyether-based polyol, polyhydric alcohols, polyhydric phenols, polyamines, alkanolamines, etc. are used singly or in mixture, using a catalyst, propylene oxide (and, if necessary, other alkylene oxides). (single or mixture), and a production method of dehydration condensation of polyhydric alcohols.

The polyhydric alcohol may be, for example, a dihydric alcohol or a trihydric alcohol. Dihydric alcohols include, for example, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, neopentyl glycol, 1,4-butanediol, 1,6-hexanediol, bisphenol A and the like. Examples of trihydric alcohols include glycerin and trimethylolpropane. Polyamines include, for example, diamines such as ethylenediamine.

These polyhydric alcohols may be used singly or in combination of two or more.

Examples of catalysts include hydroxides such as lithium, sodium, and potassium; strongly basic catalysts such as alcoholates and alkylamines; metal porphyrins; double metal cyanide complexes; Complexes: Examples include composite metal complexes such as zinc hexacyanocobaltate complexes.

Other alkylene oxides include, for example, butylene oxide, cyclohexene oxide, ethylene oxide, and styrene oxide.

(B2) The upper limit of the number average molecular weight of the polyester polyol is 5,000, preferably 3,500. On the other hand, the lower limit of the number average molecular weight is 250, preferably 500.
(B2) The polyester-based polyol has a number average molecular weight of 250 to 5,000, preferably 500 to 5,000, and more preferably 500 to 3,500.
(B2) When the number average molecular weight of the polyester-based polyol is within the above range, a coating film having sufficient extensibility can be obtained, and the viscosity of the coating composition does not become too high.
(B2) The number average molecular weight of the polyester polyol can be obtained by gel permeation chromatography (GPC) measurement.

(B2) The polyester polyol is derived from a divalent to trivalent alcohol and ε-caprolactone. More specifically, (B2) the polyester-based polyol is obtained by ring-opening polymerization of ε-caprolactone using a divalent to trivalent alcohol.

Examples of divalent to trivalent alcohols include 1,2-propylene glycol, 1,3-butylene glycol, neopentyl glycol, hydroxypivalic acid ester of neopentyl glycol, 2-methyl-1,3 propanediol, 2,3,5-trimethylpentanediol, ethylene glycol, diethylene glycol, 1,3-propanediol, 1,4-butylenediol, 1,5-pentanediol, 1,6-hexanediol, trimethylolpropane, glycerin, 1,1,7-trimethylolheptane, 1,2,7-trimethylolheptane and the like.

These divalent to trivalent alcohols may be used singly or in combination of two or more.

(B2) Commercially available polyester polyols include, for example, OD-X-2722 (trade name, manufactured by DIC Corporation, number average molecular weight 2000), OD-X-2542C (trade name, manufactured by DIC Corporation, number average molecular weight 850), PL305 (trade name, manufactured by Daicel Corporation, number average molecular weight 550), OD-X-2733 (trade name, DIC Corporation, number average molecular weight 300), OD-X-2514 (trade name, DIC manufactured by DIC Corporation, number average molecular weight 4000, OD-X-2234 (trade name, manufactured by DIC Corporation, number average molecular weight 3000).

(B2) The polyester-based polyol may be used alone or in combination of two or more.

<(C) Blocking agent>
(C) Blocking agents include, for example, compounds shown below.
(1) Alcohol compounds: methanol, ethanol, 2-propanol, 1-butanol, 2-butanol, 2-ethyl-1-hexanol, 2-methoxyethanol, 2-ethoxyethanol, 2-butoxyethanol.
(2) Alkylphenol compounds: mono- or dialkylphenols having an alkyl group having 4 or more carbon atoms as a substituent, such as n-propylphenol, iso-propylphenol, n-butylphenol, sec-butylphenol, tert-butylphenol, Monoalkylphenols such as n-hexylphenol, 2-ethylhexylphenol, n-octylphenol, n-nonylphenol; di-n-propylphenol, diisopropylphenol, isopropylcresol, di-n-butylphenol, di-tert-butylphenol, di- dialkylphenols such as sec-butylphenol, di-n-octylphenol, di-2-ethylhexylphenol and di-n-nonylphenol;
(3) Phenolic compounds: phenol, cresol, ethylphenol, styrenated phenol, hydroxybenzoate.
(4) Active methylene compounds: dimethyl malonate, diethyl malonate, methyl acetoacetate, ethyl acetoacetate, acetylacetone.
(5) Mercaptan compounds: butyl mercaptan, dodecyl mercaptan.
(6) acid amide compounds: acetanilide, acetic amide, ε-caprolactam, δ-valerolactam, γ-butyrolactam.
(7) Acid imide compounds: succinimide, maleic imide.
(8) Imidazole compounds: imidazole, 2-methylimidazole.
(9) Urea compounds: urea, thiourea, ethylene urea.
(10) Oxime compounds: formaldoxime, acetoaldoxime, acetoxime, methylethylketoxime, cyclohexanone oxime.
(11) Amine compounds: diphenylamine, aniline, carbazole, di-n-propylamine, diisopropylamine, isopropylethylamine.
(12) imine compounds: ethyleneimine, polyethyleneimine;
(13) Pyrazole compounds: pyrazole, 3-methylpyrazole, 3,5-dimethylpyrazole.

(C) The blocking agent may be used alone or in combination of two or more.

(C) The blocking agent preferably contains at least one selected from the group consisting of oxime-based compounds, pyrazole-based compounds, active methylene-based compounds, amine-based compounds, and acid amide-based compounds, from the viewpoint of storage stability. is more preferably composed of an oxime-based compound or a pyrazole-based compound, and more preferably composed of a pyrazole-based compound.

<Method for producing blocked polyisocyanate composition>
The blocked polyisocyanate composition of the present embodiment includes, for example, (A') a polyisocyanate having an allophanate group, an isocyanurate group and a urethane group obtained using (A) a diisocyanate, and (B) a polyol ((B1 ) polyether-based polyol and (B2) polyester-based polyol, or both) and (C) a blocking agent.
In the method for producing a blocked polyisocyanate composition of the present embodiment, the reaction of (A′) polyisocyanate and (B) polyol, and the reaction of (A′) polyisocyanate and (C) blocking agent are carried out simultaneously. Alternatively, one of the reactions may be performed in advance, and then the second reaction may be performed. Above all, it is preferable to first react the (A′) polyisocyanate with the (B) polyol, and then react the reactant obtained by the reaction with the (C) blocking agent.

The reactants of (A') polyisocyanate, (B) polyol, and (C) blocking agent are (A') some isocyanate groups of polyisocyanate, (B) hydroxyl groups in polyol, (A') Another part of the isocyanate group of the polyisocyanate is blocked by a (C) blocking agent to introduce a structural unit derived from the (C) blocking agent. It is an ingredient that contains
The blocked polyisocyanate composition of the present embodiment contains a reactant (polyisocyanate) into which a structural unit derived from the blocking agent (C) has been introduced, so that the coating is particularly excellent in impact resistance. It enables the formation of a film.

[(A') Method for producing polyisocyanate]
Polyisocyanate (A') can be produced by a known method using (A) diisocyanate. For example, (A) diisocyanate and alcohol are mixed and heated to perform a urethanization reaction, followed by a catalyst It can be produced by performing allophanatization and isocyanuration using.

The alcohol used may contain an ether group, an ester group, or a carbonyl group in the molecule, but is preferably a monoalcohol consisting of a saturated hydrocarbon group and a hydroxyl group, more preferably a branched monoalcohol. Such monoalcohols include, for example, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutanol, 1-pentanol, 2-pentanol, isoamyl alcohol, 1-hexanol, 2-hexanol, 1-heptanol, 1-octanol, 2-ethyl-1-hexanol, 3,3,5-trimethyl-1-hexanol, tridecanol, pentadecanol, palmityl alcohol, stearyl alcohol, cyclopentanol, cyclo hexanol, methylcyclohexanol, trimethylcyclohexanol, and the like. Among them, as a monoalcohol, because of its particularly excellent solubility in low-polarity organic solvents, isobutanol, 1-butanol, isoamyl alcohol, 1-hexanol, 1-heptanol, 1-octanol, 2-ethyl-1 -hexanol, tridecanol, pentadecanol, palmityl alcohol, stearyl alcohol or 1,3,5-trimethylcyclohexanol are preferred. Also, due to lower viscosity, 1-propanol, isobutanol, 1-butanol, isoamyl alcohol, 1-pentanol, 2-pentanol, 1-hexanol, 2-hexanol, 1-heptanol, 1-octanol, 2 -octanol, 2-ethyl-1-hexanol or 3,3,5-trimethyl-1-hexanol are preferred. In addition, isobutanol, 2-hexanol, 2-octanol, 2-ethyl-1-hexanol or 3,3,5-trimethyl-1-hexanol is preferred because of its excellent solubility in low-polarity organic solvents. preferable.

The amount of alcohol used is not limited to the following, but is preferably added such that the molar ratio of the isocyanate group of (A) diisocyanate to the hydroxyl group of alcohol is 2/1 or more and 10000/1 or less, and 5/1 or more and 1000/ The addition amount that makes it 1 or less is more preferable. When the molar ratio of the isocyanate groups of the diisocyanate (A) to the hydroxyl groups of the alcohol is at least the above lower limit, the average number of isocyanate groups in the obtained polyisocyanate (A') can be ensured to be more appropriate.

The lower limit of the urethanization reaction temperature is preferably 80°C, more preferably 85°C. On the other hand, the upper limit of the reaction temperature is preferably 120°C, more preferably 115°C.
That is, the urethanization reaction temperature is preferably 80° C. or higher and 120° C. or lower, more preferably 85° C. or higher and 115° C. or lower.

As the isocyanurate reaction catalyst, one having basicity is preferable. Examples of such an isocyanurate reaction catalyst include those shown in 1) to 7) below.
1) tetraalkylammonium hydroxides or organic weak acid salts;
2) hydroxyalkylammonium hydroxides or organic weak acid salts;
3) metal salts of alkylcarboxylic acids;
4) metal alcoholates such as sodium and potassium;
5) aminosilyl group-containing compounds such as hexamethyldisilazane;
6) Mannich bases;
7) Combined use of tertiary amines and epoxy compounds

Examples of tetraalkylammonium include tetramethylammonium and tetraethylammonium.
Examples of weak organic acids include acetic acid and capric acid.
Hydroxyalkylammonium includes, for example, trimethylhydroxypropylammonium, trimethylhydroxyethylammonium, triethylhydroxypropylammonium, triethylhydroxyethylammonium and the like.
Examples of alkylcarboxylic acids include acetic acid, caproic acid, octylic acid, myristic acid and the like.
Examples of metals constituting metal salts include tin, zinc, lead, sodium, and potassium.

Among them, from the viewpoint of catalytic efficiency, the isocyanurate reaction catalyst is preferably the above 1), 2), 3), 4) or 5), and more preferably the organic weak acid salt of 1).

The amount of the isocyanurate reaction catalyst added is preferably 10 ppm or more and 1000 ppm or less, more preferably 10 ppm or more and 500 ppm or less, and even more preferably 10 ppm or more and 100 ppm or less, relative to the mass of the raw material (A) diisocyanate.

The lower limit of the isocyanurate-forming reaction temperature is preferably 50°C, more preferably 54°C, still more preferably 57°C, and particularly preferably 60°C. On the other hand, the upper limit of the isocyanurate-forming reaction temperature is preferably 120°C, more preferably 100°C, still more preferably 90°C, and particularly preferably 80°C.
That is, the isocyanurate-forming reaction temperature is preferably 50°C or higher and 120°C or lower, more preferably 54°C or higher and 100°C or lower, still more preferably 57°C or higher and 90°C or lower, and particularly preferably 60°C or higher and 80°C or lower.
When the isocyanurate-forming reaction temperature is equal to or lower than the above upper limit, it is possible to more effectively prevent changes in properties such as coloring.

Examples of the allophanatization reaction catalyst include, but are not limited to, alkyl carboxylates of tin, lead, zinc, bismuth, zirconium, zirconyl, and the like.
Examples of alkyl carboxylates of tin (organotin compounds) include tin 2-ethylhexanoate and dibutyltin dilaurate.
Examples of lead alkyl carboxylates (organic lead compounds) include lead 2-ethylhexanoate.
Examples of zinc alkylcarboxylates (organozinc compounds) include zinc 2-ethylhexanoate and the like.
Bismuth alkyl carboxylates include, for example, bismuth 2-ethylhexanoate.
Examples of alkyl carboxylates of zirconium include zirconium 2-ethylhexanoate and the like.
Alkyl carboxylates of zirconyl include, for example, zirconyl 2-ethylhexanoate.

When the desired yield is achieved, the allophanatization reaction can be terminated by adding a deactivator for the allophanatization reaction catalyst, such as phosphoric acid or methyl p-toluenesulfonate.

The amount of the allophanatization reaction catalyst used is preferably 10 ppm or more and 10000 ppm or less, more preferably 10 ppm or more and 1000 ppm or less, and even more preferably 10 ppm or more and 500 ppm or less, relative to the raw material (A) diisocyanate.

The allophanatization reaction temperature is preferably 60° C. or higher and 160° C. or lower, more preferably 70° C. or higher and 155° C. or lower, still more preferably 80° C. or higher and 150° C. or lower, and particularly preferably 90° C. or higher and 145° C. or lower.
When the allophanatization reaction temperature is equal to or lower than the above upper limit, it is possible to more effectively prevent changes in properties such as coloring of the resulting polyisocyanate.

The reaction time for allophanatization is preferably 0.2 hours or more and 8 hours or less, more preferably 0.4 hours or more and 6 hours or less, further preferably 0.6 hours or more and 4 hours or less, and 0.8 hours or more and 3 hours or less. It is particularly preferred and most preferably 1.0 hours or more and 2 hours or less.
By setting the reaction time for allophanatization to the above lower limit or more, the viscosity can be further reduced, and by setting the reaction time to the above upper limit or less, the coloring of the polyisocyanate itself can be further suppressed.

Further, the isocyanurate-forming reaction catalyst can be used as an allophanate-forming reaction catalyst. When the allophanatization reaction is performed using the above isocyanurate reaction catalyst, an isocyanurate group-containing polyisocyanate is also produced at the same time. Among them, from the viewpoint of improving productivity from an economic standpoint, it is preferable to perform the allophanatization reaction and the isocyanuration reaction using the above isocyanuration reaction catalyst as the allophanatization reaction catalyst.

When the polymerization reaction of the urethanization reaction, the isocyanuration reaction and the allophanatization reaction reaches a desired degree of polymerization, the polymerization reaction is terminated. Termination of the polymerization reaction is not limited to the following, but can be achieved, for example, by adding an acidic compound to the reaction solution to neutralize the polymerization reaction catalyst, or by inactivating it by thermal decomposition, chemical decomposition, or the like. . Examples of acidic compounds include phosphoric acid, acidic phosphate esters, sulfuric acid, hydrochloric acid, and sulfonic acid compounds. After stopping the reaction, filtration is performed if necessary.

Since the reaction solution immediately after stopping the reaction usually contains unreacted (A) diisocyanate, it is preferable to remove this by thin film evaporator, extraction, or the like. It is preferable to control the concentration of (A) diisocyanate in the reaction solution containing (A′) polyisocyanate to 1% by mass or less by performing such a post-treatment.
The concentration of (A) the diisocyanate can be measured, for example, when the (A) diisocyanate is HDI, using the method described in Examples below.

In the reaction between (A') polyisocyanate and (B) polyol, organic metal salts, tertiary amine compounds, and alkali metal alcoholates may be used as catalysts. Examples of metals constituting the organic metal salt include tin, zinc, and lead. Examples of the alkali metals include sodium and the like.

The reaction temperature between (A′) polyisocyanate and (B) polyol is preferably −20° C. or higher and 150° C. or lower, more preferably 30° C. or higher and 130° C. or lower. When the reaction temperature is equal to or higher than the above lower limit, the reactivity tends to be higher. Further, when the reaction temperature is equal to or lower than the above upper limit, side reactions tend to be more effectively suppressed.

When (A') polyisocyanate and (B) polyol are reacted, it is preferable to completely react with polyisocyanate so that (B) polyol does not remain in an unreacted state.

When (A') polyisocyanate and (B) polyol are reacted, the ratio of the amount of (B) polyol to the total amount of (A') polyisocyanate and (B) polyol is 5 mass. % or more and 45% by mass or less is preferable.

Next, the reaction (hereinafter sometimes referred to as "blocking reaction") of (A') a polyisocyanate, a reactant obtained by reacting (B) a polyol, and (C) a blocking agent, It can be done with or without the presence of solvent.

The amount of the blocking agent (C) used is usually 80 mol% or more and 200 mol% or less, or 90 mol% or more and 150 mol%, relative to the total molar amount of the isocyanate groups in the (A') polyisocyanate. or less, more preferably 93 mol % or more and 130 mol % or less.

When using a solvent, a solvent inert to isocyanate groups may be used.
When a solvent is used, the content of non-volatile matter derived from (A') the polyisocyanate and (C) the blocking agent relative to 100 parts by mass of the blocked polyisocyanate composition is usually 10 parts by mass or more and 95 parts by mass or less. It is preferably 15 parts by mass or more and 80 parts by mass or less, more preferably 20 parts by mass or more and 75 parts by mass or less.

In the blocking reaction, organic metal salts such as tin, zinc and lead, tertiary amine compounds, alcoholates of alkali metals such as sodium, and the like may be used as catalysts.
The amount of the catalyst to be added varies depending on the temperature of the blocking reaction, etc., but it is usually 0.05 parts by mass or more and 1.5 parts by mass or less with respect to 100 parts by mass of the (A') polyisocyanate. It is preferably 0.1 parts by mass or more and 1.0 parts by mass or less.

The blocking reaction can generally be carried out at -20°C or higher and 150°C or lower, preferably at 0°C or higher and 100°C or lower, more preferably at 10°C or higher and 90°C or lower. When the temperature of the blocking reaction is equal to or higher than the above lower limit, the reaction rate can be further increased, and when it is equal to or lower than the above upper limit, side reactions can be further suppressed.

After the blocking reaction, a neutralization treatment may be performed by adding an acidic compound or the like.
As said acidic compound, an inorganic acid may be used and an organic acid may be used. Examples of inorganic acids include hydrochloric acid, phosphorous acid, and phosphoric acid. Examples of organic acids include methanesulfonic acid, p-toluenesulfonic acid, dioctyl phthalate, dibutyl phthalate and the like.

<Other ingredients>
The blocked polyisocyanate composition of the present embodiment can further contain a solvent in addition to the blocked polyisocyanate. Water, an organic solvent, etc. are mentioned as a solvent.

Examples of the organic solvent include aliphatic hydrocarbon solvents, alicyclic hydrocarbon solvents, ketone solvents, ester solvents, aromatic solvents, glycol solvents, ether solvents, and halogenated hydrocarbon solvents. , pyrrolidone solvents, amide solvents, sulfoxide solvents, lactone solvents, amine solvents and the like.
Examples of aliphatic hydrocarbon solvents include hexane, heptane, octane and the like. Examples of alicyclic hydrocarbon solvents include cyclohexane and methylcyclohexane. Examples of ketone solvents include acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone and the like. Examples of ester solvents include methyl acetate, ethyl acetate, butyl acetate, isobutyl acetate, methyl lactate, ethyl lactate and the like. Examples of aromatic solvents include toluene, xylene, diethylbenzene, mesitylene, anisole, benzyl alcohol, phenyl glycol, chlorobenzene and the like. Examples of glycol-based solvents include ethylene glycol monoethyl ether acetate, 3-methyl-3-methoxybutyl acetate, dipropylene glycol monomethyl ether, propylene glycol monomethyl ether, and propylene glycol monomethyl ether acetate. Examples of ether solvents include diethyl ether, tetrahydrofuran, dioxane and the like. Halogenated hydrocarbon solvents include, for example, dichloromethane, 1,2-dichloroethane, chloroform and the like. Examples of pyrrolidone solvents include N-methyl-2-pyrrolidone. Examples of amide solvents include N,N-dimethylacetamide and N,N-dimethylformamide. Examples of sulfoxide-based solvents include dimethylsulfoxide and the like. Examples of lactone solvents include γ-butyrolactone. Examples of amine-based solvents include morpholine and the like.

An organic solvent may be used individually by 1 type, and may be used in combination of 2 or more type.

As the solvent, water or an organic solvent may be used alone, or water and an organic solvent may be used in combination. When water and an organic solvent are used in combination, the organic solvent can be a solvent that tends to be miscible with water.
Solvents that tend to be miscible with water include diethylene glycol dimethyl ether, diethylene glycol diethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, propylene glycol dimethyl ether, dipropylene glycol dimethyl ether, isobutanol, butyl glycol, and N-methylpyrrolidone. , butyl diglycol, butyl diglycol acetate. Among them, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, propylene glycol monomethyl ether, propylene glycol dimethyl ether, dipropylene glycol dimethyl ether, isobutanol, butyl glycol, N-methylpyrrolidone, or butyl diglycol are preferable, and diethylene glycol dimethyl ether, diethylene glycol diethyl ether, propylene glycol. Dimethyl ether or butipropylene glycol dimethyl ether are more preferred. These solvents may be used individually by 1 type, and may be used in combination of 2 or more type.

The polyisocyanate composition of the present embodiment can further contain an ionic surfactant in addition to the blocked polyisocyanate. The ionic surfactant used in the blocked polyisocyanate composition of the present embodiment preferably contains substantially no water. Examples of ionic surfactants include anionic surfactants and cationic surfactants.

As the anionic surfactant, a carboxylate type, sulfate type, sulfonate type, or phosphate type is suitable. alkyl) sodium disulfate, sodium alkyl diphenyl ether disulfonate, sodium di(alkyl having 8 to 20 carbon atoms) sodium sulfosuccinate, and the like.

Suitable cationic surfactants include quaternary ammonium salts, pyridinium salts, and imidazolinium salts. Examples include (alkyl having 8 to 20 carbon atoms) trimethylammonium bromide, alkyl)pyridinium bromide, imidazoirinium laurate, and the like.

The content of the ionic surfactant is preferably 0.5% by mass or more and less than 5% by mass, and 0.5% by mass or more and 2% by mass or less with respect to the total mass (100% by mass) of the block polyisocyanate composition. is more preferable, and 0.5% by mass or more and 1.5% by mass or less is even more preferable. When the content of the ionic surfactant is at least the above lower limit, it tends to be more excellent in dispersibility. tend to be better.

In addition to the blocked polyisocyanate, the blocked polyisocyanate composition of the present embodiment contains various additives such as a curing accelerator catalyst, an antioxidant, an ultraviolet absorber, a light stabilizer, a pigment, a leveling agent, and a plasticizer. can be done.

Examples of curing acceleration catalysts include tin compounds, zinc compounds, titanium compounds, cobalt compounds, bismuth compounds, zirconium compounds, and amine compounds. Examples of tin-based compounds include dibutyltin dilaurate, dibutyltin diacetate, dioctyltin dilaurate, dimethyltin dineodecanoate, tin bis(2-ethylhexanoate), and the like. Examples of zinc compounds include zinc 2-ethylhexanoate and zinc naphthenate. Examples of titanium compounds include titanium 2-ethylhexanoate and titanium diisopropoxybis(ethylacetonate). Examples of cobalt compounds include cobalt 2-ethylhexanoate and cobalt naphthenate. Examples of bismuth compounds include bismuth 2-ethylhexanoate and bismuth naphthenate. Examples of zirconium compounds include zirconium tetraacetylacetonate, zirconyl 2-ethylhexanoate, and zirconyl naphthenate.

Antioxidants include, for example, hindered phenol compounds, phosphorus compounds, sulfur compounds and the like. Phosphorus compounds include, for example, phosphites and acid phosphates.
Examples of ultraviolet absorbers include benzotriazole-based compounds, triazine-based compounds, and benzophenone-based compounds.
Examples of light stabilizers include hindered amine-based compounds, benzotriazole-based compounds, triazine-based compounds, benzophenone-based compounds, and benzoate-based compounds.
Examples of pigments include titanium oxide, carbon black, indigo, pearl mica, and aluminum.
Examples of leveling agents include silicone oil and the like.
Examples of plasticizers include phthalates, phosphoric acid compounds, polyester compounds, and the like.

[Preferred Embodiment of Polyisocyanate Component]
In the blocked polyisocyanate composition of the present embodiment, the polyisocyanate component preferably contains substantially no free isocyanate groups. The term "free isocyanate group" as used herein refers to any compound, for example, (A') polyisocyanate and its raw material (A) diisocyanate, (A') auxiliary raw material in the production of polyisocyanate, (B) polyol, (C) Indicates an isocyanate group that does not form a bond with a blocking agent or the like and retains reactivity. On the other hand, the term "non-free isocyanate group" refers to any compound, for example, (A') polyisocyanate and its raw material (A) diisocyanate, (A') auxiliary raw material for polyisocyanate production, (B) polyol, (C) Indicates an isocyanate group that forms a bond with a blocking agent or the like and does not retain reactivity.

The blocked polyisocyanate composition of the present embodiment preferably contains no free isocyanate groups, or contains only a very small amount of free isocyanate groups to the extent that the effects of the blocked polyisocyanate composition of the present embodiment are not hindered. is preferred. The content of free isocyanate groups in the blocked polyisocyanate composition of the present embodiment is preferably 1 mol% or less, preferably 0.5 mol% or less, relative to the total molar amount of isocyanate groups derived from (A') polyisocyanate. More preferably, 0.1 mol % is even more preferable, and 0 mol % is particularly preferable.

The reactants of (A′) polyisocyanate, (B) polyol, and (C) blocking agent do not contain free isocyanate groups, i.e., some isocyanate groups of (A′) polyisocyanate and (B ) The hydroxyl group of the polyol forms a bond, (B) the hydroxyl group derived from the polyol is introduced, and (A′) all the remaining isocyanate groups of the polyisocyanate are blocked by (C) a blocking agent. , (C) a structural unit derived from a blocking agent is preferably introduced.

<Physical properties of blocked polyisocyanate composition>
In the blocked polyisocyanate composition of the present embodiment, the effective isocyanate group content (effective NCO content) is preferably 3% by mass or more and 15% by mass or less, more preferably 4% by mass or more and 14.5% by mass or less.
The effective NCO content can be calculated using, for example, the following formula.

Effective NCO content [mass%]
= [(non-volatile content [% by mass] of the blocked polyisocyanate composition) x {(mass of (A') polyisocyanate used in the blocking reaction) x (NCO content of (A') polyisocyanate [% by mass] )}]/(mass of blocked polyisocyanate composition after blocking reaction)

<Application>
The blocked polyisocyanate composition of this embodiment can be used as a raw material for paints, inks, adhesives, casting materials, elastomers, foams, and plastic materials.

≪Paint composition≫
The coating composition of the present embodiment contains a polyol as a main component and the blocked polyisocyanate composition as a curing agent component.
The coating composition of this embodiment is suitable for forming a coating film, which will be described later. In addition, since the coating composition of the present embodiment contains the above-described blocked polyisocyanate composition, the pot life is long and the coating composition is excellent in handleability.

The coating composition of the present embodiment may contain other main components in addition to the polyol as the main component, but the coating composition of the present embodiment preferably contains only the polyol as the main component. .
The coating composition of the present embodiment may contain other curing agent components in addition to the blocked polyisocyanate composition as a curing agent component. It preferably contains only the blocked polyisocyanate composition.

The lower limit of the hydroxyl value of the polyol is 5 mgKOH/g, preferably 10 mgKOH/g, more preferably 15 mgKOH/g, still more preferably 20 mgKOH/g. The upper limit of the hydroxyl value of the polyol is 200 mgKOH/g, preferably 160 mgKOH/g, more preferably 120 mgKOH/g, even more preferably 80 mgKOH/g.
That is, the hydroxyl value of the polyol is 5 mgKOH/g to 200 mgKOH/g, preferably 10 mgKOH/g to 160 mgKOH/g, may be 15 mgKOH/g to 120 mgKOH/g, and may be 20 mgKOH/g to 80 mgKOH. /g or less.
When the hydroxyl value is within the above range, a more flexible and tougher coating film can be obtained.

<Polyol>
Examples of polyols include acrylic polyols, polyester polyols, polyether polyols, polyolefin polyols, silicon-containing polyols, fluorine-containing polyols, polycarbonate polyols, epoxy resins, alkyd polyols, and the like. .
As the polyol, urethane-modified acrylic polyol, urethane-modified polyester polyol or urethane-modified polyol obtained by modifying acrylic polyol, polyester polyol or polyether polyol with aliphatic diisocyanate, alicyclic diisocyanate or polyisocyanate obtained therefrom. Modified polyols such as ether polyols can also be used.

Each of the above polyols and modified polyols may be used alone or in combination of two or more. A polyol and a modified polyol may be used in combination.

Polyols can be produced by known techniques, and methods for producing typical acrylic polyols, polyester polyols, and polyether polyols will be described below.

[Acrylic polyols]
Acrylic polyols, for example, polymerize only polymerizable monomers having one or more active hydrogens in one molecule, or polymerizable monomers having one or more active hydrogens in one molecule, and optionally , can be obtained by copolymerizing the polymerizable monomer and another copolymerizable monomer.

Examples of the polymerizable monomer having one or more active hydrogens in one molecule include the following (i) to (vi). These may be used alone or in combination of two or more.
(i) acrylic acid esters having active hydrogen such as 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate and 2-hydroxybutyl acrylate;
(ii) Methacrylic acids having active hydrogen such as 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-hydroxybutyl methacrylate, 3-hydroxypropyl methacrylate, and 4-hydroxybutyl methacrylate esters.
(iii) (meth)acrylic acid esters having polyvalent active hydrogen, such as (meth)acrylic acid monoesters of triols; Examples of the triol include glycerin and trimethylolpropane.
(iv) Monoethers of polyether polyols and the above (meth)acrylic acid esters having active hydrogen. Examples of the polyether polyols include polyethylene glycol, polypropylene glycol, polybutylene glycol and the like.
(v) an adduct of glycidyl (meth)acrylate and a monobasic acid; Examples of the monobasic acid include acetic acid, propionic acid, p-tert-butylbenzoic acid and the like.
(vi) an adduct obtained by ring-opening polymerization of the active hydrogen of the (meth)acrylic acid ester having an active hydrogen with a lactone; Examples of the lactones include ε-caprolactone and γ-valerolactone.

Other monomers copolymerizable with the polymerizable monomer include, for example, the following (i) to (v). These may be used alone or in combination of two or more.
(i) methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, methacrylic acid (Meth)acrylic acid esters such as isobutyl, n-hexyl methacrylate, cyclohexyl methacrylate, lauryl methacrylate and glycidyl methacrylate;
(ii) unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid and itaconic acid;
(iii) Unsaturated amides such as acrylamide, N-methylol acrylamide and diacetone acrylamide.
(iv) vinyl monomers having a hydrolyzable silyl group such as vinyltrimethoxysilane, vinylmethyldimethoxysilane, γ-(meth)acrylopropyltrimethoxysilane;
(v) Other polymerizable monomers such as styrene, vinyl toluene, vinyl acetate, acrylonitrile, dibutyl fumarate.

Specifically, acrylic polyols can be obtained, for example, by solution-polymerizing the above monomers in the presence of a radical polymerization initiator such as a known peroxide or an azo compound, and diluting with an organic solvent or the like as necessary. can be manufactured by

When the coating composition of the present embodiment contains a solvent with a large amount of water, it can be produced by a known method such as solution polymerization of the above-mentioned monomers and conversion to a water layer, or emulsion polymerization. In that case, water-solubility or water-dispersibility can be imparted to acrylic polyols by neutralizing acidic moieties such as carboxylic acid-containing monomers such as acrylic acid and methacrylic acid and sulfonic acid-containing monomers with amines or ammonia. can.

[Polyester polyols]
Polyester polyols can be obtained, for example, by condensing a dibasic acid alone or a mixture of two or more kinds and a polyhydric alcohol alone or a mixture of two or more kinds.
Examples of the dibasic acid include carboxylic acids such as succinic acid, adipic acid, dimer acid, maleic anhydride, phthalic anhydride, isophthalic acid, terephthalic acid, and 1,4-cyclohexanedicarboxylic acid.
Examples of the polyhydric alcohol include ethylene glycol, propylene glycol, diethylene glycol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, trimethylpentanediol, cyclohexanediol, trimethylolpropane, glycerin, and pentaerythritol. , 2-methylolpropanediol, ethoxylated trimethylolpropane, and the like.

Specifically, the polyester polyols can be produced, for example, by mixing the above components and heating at about 160° C. or higher and 220° C. or lower to perform a condensation reaction. Further, for example, polycaprolactones obtained by ring-opening polymerization of lactones such as ε-caprolactone using a polyhydric alcohol can also be used as polyester polyols.

[Polyether polyols]
Polyether polyols can be obtained, for example, using any one of the following methods (1) to (3).
(1) A method of randomly or block-adding an alkylene oxide alone or a mixture to a polyhydric hydroxy compound alone or a mixture using a catalyst to obtain polyether polyols.
Examples of the catalyst include hydroxides of lithium, sodium, potassium, etc., strongly basic catalysts, double metal cyanide complexes, and the like. Examples of strongly basic catalysts include alcoholates, alkylamines, and the like. Examples of double metal cyanide complexes include metal porphyrins and zinc hexacyanocobaltate complexes.
Examples of the alkylene oxide include ethylene oxide, propylene oxide, butylene oxide, cyclohexene oxide, and styrene oxide.

(2) A method of reacting a polyamine compound with an alkylene oxide to obtain a polyether polyol.
Examples of the polyamine compound include ethylenediamines.
Examples of the alkylene oxide include those exemplified in (1) above.

(3) A method of obtaining so-called polymer polyols by polymerizing acrylamide or the like using the polyether polyols obtained in the above (1) or (2) as a medium.
Examples of the polyvalent hydroxy compound include those shown in (i) to (vi) below.
(i) diglycerin, ditrimethylolpropane, pentaerythritol, dipentaerythritol, etc.;
(ii) sugar alcohol compounds such as erythritol, D-threitol, L-arabinitol, ribitol, xylitol, sorbitol, mannitol, galactitol and rhamnitol;
(iii) monosaccharides such as arabinose, ribose, xylose, glucose, mannose, galactose, fructose, sorbose, rhamnose, fucose, ribodesose;
(iv) disaccharides such as trehalose, sucrose, maltose, cellobiose, gentiobiose, lactose, melibiose;
(v) trisaccharides such as raffinose, gentianose, melezitose;
(vi) tetrasaccharides such as stachyose

<NCO/OH>
In the coating composition of this embodiment, the mixing ratio of the curing agent to the main agent can be represented by the molar ratio of isocyanate groups to hydroxyl groups (NCO/OH). The lower limit of NCO/OH is preferably 0.1, more preferably 0.3, still more preferably 0.4, and particularly preferably 0.5. On the other hand, the upper limit of NCO/OH is preferably 5.0, more preferably 4.0, even more preferably 3.0, and particularly preferably 2.0.
That is, NCO/OH is preferably 0.1 or more and 5.0 or less, more preferably 0.3 or more and 4.0 or less, further preferably 0.4 or more and 3.0 or less, and 0.5 or more and 2.0 or less. Especially preferred.
When the NCO/OH is within the above range, a tougher coating film can be formed.

<Various additives>
In addition to the above polyol and the above polyisocyanate composition, the coating composition of the present embodiment can improve adhesion of coloring pigments, dyes, and coating films depending on the purpose and application within a range that does not impair the effects of the present invention. Silane coupling agents, UV absorbers, curing accelerators, light stabilizers, matting agents, coating surface hydrophilic agents, catalysts for curing acceleration, drying improvers, leveling agents, antioxidants, plasticizers, Various additives used in the art such as surfactants may also be included.

The color pigment may be an inorganic pigment or an organic pigment. Examples of inorganic pigments include carbon black and titanium oxide, which have good weather resistance. Examples of organic pigments include phthalocyanine blue, phthalocyanine green, quinacridone red, indanthrene orange, and isoindolinone yellow.

Silane coupling agents include, for example, 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, ureidopropyltriethoxysilane, vinyltriethoxysilane, Ethoxysilane, Vinyltrimethoxysilane, 3-Methacryloxypropyltrimethoxysilane, 3-Methacryloxypropyltriethoxysilane, 2-(3,4-Epoxycyclohexyl)ethyltrimethoxysilane, 3-Glycidoxypropyltrimethoxysilane , 3-mercaptopropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, methyltriethoxysilane, methyltrimethoxysilane and the like.

Examples of the ultraviolet absorber include benzophenone-based, benzotriazole-based, triazine-based, and cyanoacrylate-based ultraviolet absorbers.

Examples of light stabilizers include hindered amine-based light stabilizers, etc. Specific commercial products include, for example, Adekastab LA62, Adekastab LA67 (trade names, all manufactured by Adeka Argas Chemicals), Tinuvin 292, Tinuvin 144, Tinuvin 123, Tinuvin 440 (trade name, all manufactured by Ciba Specialty Chemicals), Sanol LS765 (trade name, manufactured by Sankyo Lifetech Co., Ltd.), and the like.

The matting agent includes, for example, ultrafine synthetic silica, etc., and when the matting agent is used, a coating film with an elegant semi-gloss and matte finish can be formed.

A silicate compound is preferable as the coating film surface hydrophilizing agent. By containing the silicate compound, when a coating film is produced using the coating composition of the present embodiment, the coating film surface becomes hydrophilic, and resistance to rain streak staining is exhibited. Since the silicate compound reacts with hydroxyl groups, it is preferably added to the blocked polyisocyanate composition, which is the curing agent component, when mixed in advance. Alternatively, they may be mixed at the same time when the polyol, which is the main component, and the blocked polyisocyanate composition, which is the curing agent component, are mixed.
Examples of silicate compounds include tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, tetraisopropoxysilane, tetra-n-butoxysilane, tetraisobutoxysilane, tetra-tert-butoxysilane, dimethoxydiethoxysilane. , tetraphenoxysilane, condensates thereof, and the like. Among them, the silicate compound is preferably a condensate of tetramethoxysilane or a condensate of tetraethoxysilane, because the surface of the coating film is likely to be hydrophilic when the coating film is produced.

Examples of catalysts for accelerating curing include, but are not limited to, metal salts, tertiary amines, and the like.
Examples of metal salts include dibutyltin dilaurate, tin 2-ethylhexanoate, zinc 2-ethylhexanoate, cobalt salts and the like.
Examples of tertiary amines include triethylamine, pyridine, methylpyridine, benzyldimethylamine, N,N-dimethylcyclohexylamine, N-methylpiperidine, pentamethyldiethylenetriamine, N,N'-endoethylenepiperazine, N,N' - dimethylpiperazine and the like.

Examples of dryness improvers include CAB (cellulose acetate butrate) and NC (nitrocellulose).

Examples of leveling agents include, but are not limited to, silicones, aerosils, waxes, stearates, and polysiloxanes.

Examples of plasticizers include, but are not limited to, phthalates, phosphates, fatty acid esters, pyromellitic esters, epoxy plasticizers, polyether plasticizers, liquid rubbers, and non-aromatic paraffin oils. etc.
Examples of phthalates include dioctyl phthalate, dibutyl phthalate, diethyl phthalate, butylbenzyl phthalate, di-2-ethylhexyl phthalate, diisodecyl phthalate, diundecyl phthalate, and diisononyl phthalate.
Phosphate esters include, for example, tricresyl phosphate, triethyl phosphate, tributyl phosphate, tri-2-ethylhexyl phosphate, trimethylhexyl phosphate, tris-chloroethyl phosphate, tris-dichloropropyl phosphate and the like.
Examples of fatty acid esters include trimellitic acid esters, dipentaerythritol esters, dioctyl adipate, dimethyl adipate, di-2-ethylhexyl azelate, dioctyl azelate, dioctyl sebacate, di-2-ethylhexyl sebacate, and methyl acetyl lysinocate. Examples of trimellitates include octyl trimellitate and isodecyl trimellitate.
Examples of pyromellitic acid esters include pyromellitic acid octyl ester and the like.
Examples of epoxy plasticizers include epoxidized soybean oil, epoxidized linseed oil, and epoxidized fatty acid alkyl esters.
Examples of polyether plasticizers include adipate ether esters and polyethers.
Examples of liquid rubber include liquid NBR, liquid acrylic rubber, and liquid polybutadiene.

Examples of surfactants include known anionic surfactants, cationic surfactants, amphoteric surfactants, and the like.

<Method for producing paint composition>
The coating composition of the present embodiment is useful as a solvent coating composition, and can be obtained by the manufacturing method described below.

When the coating composition of the present embodiment is a solvent-based coating composition, for example, first, a polyol or a solvent dilution thereof as a main agent, and, if necessary, various additives are added to the above poly An isocyanate composition is added as a curing agent. Then, if necessary, a solvent is further added to adjust the viscosity. A solvent-based coating composition can then be obtained by stirring by hand or by stirring with a stirring device such as a Masellar.
Further, the order of mixing the main agent component containing the polyol as the main component, the curing agent component containing the polyisocyanate composition as the main component, and the various additives is not particularly limited. can be done.
1) A curing agent component is mixed with a main component in which various additives are mixed in advance at a coating site.
2) After mixing the main agent component and the curing agent component at the painting site, various additives are mixed.
3) A curing agent component, which is premixed with various additives, is mixed with the main component, which is premixed with various additives, at the coating site.

<Application>
The coating composition of the present embodiment is not limited to the following, but for example, spray coating, air spray coating, brush coating, coating by dipping method, roll coating, curtain flow coating, bell coating, electrostatic coating, etc. can be used.
In addition, the coating composition of the present embodiment is also useful as a coating for molded articles composed of materials such as metals (steel sheets, surface-treated steel sheets, etc.), plastics, wood, films, inorganic materials, and the like. It is particularly suitable as a coating for plastics.
Further, the coating composition of the present embodiment is suitable for, for example, architectural coatings, heavy-duty anticorrosive coatings, automotive coatings, information appliance coatings, and information equipment coatings such as personal computers and mobile phones. It is particularly suitable as a paint (for example, top clear paint) for automobile bodies, metal parts for automobiles, plastic parts for automobiles, metal parts for information home appliances, or plastic parts for information home appliances.

≪Paint film≫
The coating film of the present embodiment is obtained by curing the above coating composition, always exhibits stable quality, and is excellent in water resistance, weather resistance, toughness, hardness and impact resistance.

<Method for producing coating film>
The method for producing a coating film of the present embodiment is a method including the step of curing the coating composition.

The coating film of the present embodiment is formed by coating the above coating composition with a known coating such as spray coating, air spray coating, brush coating, dip coating, roll coating, curtain flow coating, bell coating, and electrostatic coating. It can be produced by curing after coating on the object to be coated using the method.
Examples of the object to be coated include those similar to the molded article composed of the materials exemplified in the "applications" of the coating composition.

Hereinafter, the present embodiment will be described in more detail by showing specific examples and comparative examples, but the present embodiment is not limited by the following examples and comparative examples as long as the gist thereof is not exceeded. .

[Physical properties 1]
(F/E, D/E, and F/(D+F))
The resulting block polyisocyanate composition was subjected to ¹³ C-NMR measurement using Biospin Avance 600 (trade name) manufactured by Bruker. Specific measurement conditions were as follows.

(Measurement condition)
¹³ C-NMR device: AVANCE600 (manufactured by Bruker)
Cryoprobe (manufactured by Bruker)
CryoProbe®
CPDUL
600S3-C/HD-05Z
Resonance frequency: 150MHz
Concentration: 60wt/vol%
Shift reference: CDCl ₃ (77 ppm)
Number of times of integration: 10000 times Pulse program: zgpg30 (proton complete decoupling method, waiting time 2 sec)

Each molar ratio of allophanate groups, isocyanurate groups and urethane groups was determined by dividing the integrated value of the following signals by the number of carbon atoms being measured. Then, where D is the number of moles of allophanate groups, E is the number of moles of isocyanurate groups, and F is the number of moles of urethane groups before blocking, F/E, D/E, and F/(D+F) are calculated. bottom.

Isocyanurate group: (Integral value around 148.6 ppm) ÷ 3
Urethane group: (integrated value near 156.5 ppm)/1
Allophanate group: (Integral value around 154 ppm) ÷ 1

[Physical properties 2]
(Viscosity at 25°C)
The viscosity was measured at 25° C. with an E-type viscometer (manufactured by Tokimec Co., Ltd.). A standard rotor (1°34′×R24) was used. The number of revolutions is as follows.

(Rotational speed)
100r. p. m. (When less than 128 mPa s)
50r. p. m. (In the case of 128 mPa s or more and less than 256 mPa s)
20r. p. m. (In the case of 256 mPa·s or more and less than 640 mPa·s)
10r. p. m. (640 mPa·s or more and less than 1280 mPa·s)
5r. p. m. (In the case of 1280 mPa s or more and less than 2560 mPa s)

[Physical properties 3]
(Isocyanate group content (NCO content))
The NCO content was determined by back titration with 1N hydrochloric acid after neutralizing the isocyanate groups with an excess of 2N amine.

[Physical properties 4]
(HDI monomer concentration)
The polystyrene-based number average molecular weight was measured by GPC measurement under the measurement conditions shown below. Then, the peak area % of the molecular weight (168) corresponding to the unreacted HDI monomer was calculated as the HDI monomer concentration.

(Measurement condition)
Apparatus: HLC-8320GPC (TOSOH)
Column: TSKgelSuperH2500 x 1 (TOSOH)
TSKgel Super H4000 x 1 (TOSOH)
TSKgel Super H5000 x 1 (TOSOH)
TSKgel Super H6000 x 1 (TOSOH)
Carrier: Tetrahydrofuran Flow rate: 0.6 mL/min Sample concentration: 1.0% by mass
Injection volume: 20 μL
Temperature: 40°C
Detection method: differential refractometer

<Evaluation method of coating composition>
Using each block polyisocyanate composition, coating compositions were produced and evaluated as follows.

[Production Example 1]
(Manufacture of paint composition)
Acrylic polyol (manufactured by Allnex, "Setalux 1152" (product name), resin solid content concentration 61%, hydroxyl value 139 mg KOH/resin g) and each block polyisocyanate composition, the equivalent ratio of hydroxyl groups to isocyanate groups is 1: 1 was blended. After that, the solid content of the paint is adjusted to 50% with butyl acetate, and a tin catalyst (U-100 manufactured by Nitto Kasei Co., Ltd.) is mixed in an amount of 3000 ppm in mass ratio with respect to the solid content of the resin. to obtain each coating composition.

[Evaluation 1]
(Pot life of paint composition)
After each coating composition was mixed, it was kept in an oven at 40° C. for 72 hours. Next, the state of the resin content in each coating composition after this holding was visually observed. The pot life of each coating composition was evaluated according to the evaluation criteria shown below.
(Evaluation criteria)
〇: The paint composition maintains a liquid state ×: The paint composition solidifies

<Method for evaluating coating film>
Using each of the coating compositions obtained above, coating films were produced and evaluated as follows.

[Evaluation 2]
(water resistant)
Each coating composition is applied to a glass plate so that the film thickness after drying is 30 μm, left at room temperature for 15 minutes, then cured (baked) in an oven at 150 ° C. for 30 minutes, 23 ° C., relative humidity 50. Each coating film was obtained by allowing to stand for 1 day under conditions of %. After cooling this coating film at room temperature, it was held for 72 hours under the conditions of 60° C. and 87% relative humidity. After that, it was allowed to stand at room temperature for 60 minutes, and the coating film after this standing was visually observed. The water resistance of each coating film was evaluated according to the evaluation criteria shown below.
(Evaluation criteria)
◎: Whitening, spots, etc. were not observed ○: Whitening, spots were observed in 1 or 2 places ×: Whitening, spots were observed in 3 or more places

[Evaluation 3]
(Weatherability)
Each coating composition was applied to a white enamel coated plate with an applicator so that the film thickness after drying was 40 μm, cured (baked) in an oven at 150° C. for 30 minutes, and placed at 20° C. and a relative humidity of 63%. After curing the coating film for 1 week, the coated plate was evaluated for weather resistance. A due panel weather meter (manufactured by Suga Test Instruments) was used for weather resistance evaluation. According to JIS D0205, the evaluation conditions were irradiation intensity of 30 W/m ² , panel temperature of 60° C., irradiation time and dew condensation time were cycled every 4 hours. The water resistance of each coating film was evaluated according to the evaluation criteria shown below.
(Evaluation criteria)
◎: Gloss retention rate of 80% or more at 1200 hours of exposure time ○: Gloss retention rate of 70% or more and less than 80% at 1200 hours of exposure time ×: Gloss retention rate of 70 at 1200 hours exposure time less than %

[Evaluation 4]
(Toughness (stress at 60% elongation))
Each coating composition was applied to a polypropylene plate, dried by heating (baking) at 150° C. for 30 minutes, and then dried at 23° C. and a relative humidity of 50% for 1 day to prepare a coating film. Next, the prepared coating film is cut into strips to prepare a test piece, which is attached to a tensile tester (Tensilon universal tester) so that it has a length of 20 mm and a width of 10 mm, and a tensile speed of 20 mm / min at a test temperature of 23 ° C. and measured the stress at an elongation of 60%. The results were evaluated according to the following evaluation criteria.
(Evaluation criteria)
◎: Stress is 20 MPa or more ○: Stress is 5 MPa or more and less than 20 MPa ×: Stress is less than 5 Ma or elongation is less than 60%

[Evaluation 5]
(hardness)
Each coating composition was applied on a glass plate, dried by heating (baking) at 150° C. for 30 minutes, and then dried for 1 day in an environment of 23° C. and 50% relative humidity to prepare a coating film. The Konig hardness of the coating film was measured and evaluated according to the following evaluation criteria.
(Evaluation criteria)
◎: 30 times or more ○: 10 times or more and less than 30 times ×: less than 10 times

[Evaluation 6]
(shock resistance)
Each coating composition is coated on a mild steel plate, dried by heating (baking) at 150 ° C. for 30 minutes, and then dried for 1 day in an environment of 23 ° C. and a relative humidity of 50% to prepare a coating film. and obtained a test piece. According to JIS K 5600-5-3, using a DuPont impact tester (mass of weight 1000 g, drop height of weight 30 or 20 cm, shooting radius R1/8), among the above test pieces, the coating film A weight was dropped against the surface on which the weight was provided. Next, the coating film side surface of the test piece was visually observed, and the impact resistance was evaluated according to the following evaluation criteria.
(Evaluation criteria)
⊚: No lift or peeling of the paint film even when a weight is dropped from a height of 30 cm.
◯: The coating film peeled off when the weight was dropped from a height of 30 cm, and neither lifting nor peeling of the coating film occurred when the weight was dropped from a height of 20 cm.
x: The coating film was peeled off when the weight was dropped from a height of 20 cm.

<(A') Synthesis of polyisocyanate>
[Synthesis Example 1]
(Synthesis of polyisocyanate A'-1)
A four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, a nitrogen blowing tube and a dropping funnel was filled with a nitrogen atmosphere, HDI: 1000 g and 2-ethylhexanol: 100 g were charged, and the mixture was stirred at 90°C for 1 hour. A urethane-forming reaction was carried out. As an allophanatization and isocyanuration catalyst, 1 g of a solution of tetramethylammonium caprate diluted with isobutanol to 5% by mass was added to carry out an isocyanuration reaction. When the refractive index of the reaction solution reached 0.015, phosphoric acid was added to stop the reaction. After filtration of the reaction solution, it was purified twice under conditions of 160° C. and 0.2 Torr using a thin film evaporator to obtain polyisocyanate A′-1. The obtained polyisocyanate A'-1 had a viscosity of 400 mPa·s (25° C.), an NCO content of 17.7% by mass, and an HDI monomer concentration of 0.11% by mass.

[Synthesis Example 2]
(Synthesis of polyisocyanate A'-2)
HDI: 1000 g was charged into the same apparatus as in Synthesis Example 1, and the temperature in the reactor was maintained at 80°C for 2 hours while stirring. After that, 1 g of a solution of tetramethylammonium caprate diluted with isobutanol to 5% by mass was added as an isocyanurate-forming catalyst to carry out an isocyanurate-forming reaction. When the refractive index of the reaction liquid increased to 0.012, phosphoric acid was added to terminate the reaction. After filtering the reaction solution, unreacted HDI was removed in the same manner as in Synthesis Example 1-1 to obtain polyisocyanate A'-2. The obtained polyisocyanate A'-2 had a viscosity of 1300 mPa·s (25° C.), an NCO content of 23.1% by mass, and an HDI monomer concentration of 0.11% by mass.

[Synthesis Example 3]
(Synthesis of polyisocyanate A'-3)
1000 g of HDI and 30 g of 2-ethylhexanol were charged into the same apparatus as in Synthesis Example 1, and urethanization reaction was carried out at 90° C. for 1 hour while stirring. As an allophanatization and isocyanuration catalyst, 1 g of a solution of tetramethylammonium caprate diluted with isobutanol to 5% by mass was added to carry out an isocyanuration reaction. When the refractive index of the reaction liquid increased to 0.012, phosphoric acid was added to terminate the reaction. After filtering the reaction solution, unreacted HDI was removed in the same manner as in Synthesis Example 1 to obtain polyisocyanate A'-3. The obtained polyisocyanate A'-3 had a viscosity of 500 mPa·s (25° C.), an NCO content of 20.6% by mass, and an HDI monomer concentration of 0.11% by mass.

[Synthesis Example 4]
(Synthesis of polyisocyanate A'-4)
1000 g of HDI and 30 g of 2-ethylhexanol were charged into the same apparatus as in Synthesis Example 1, and urethanization reaction was carried out at 80° C. for 1 hour while stirring. As an allophanatization and isocyanuration catalyst, 1 g of a solution of tetramethylammonium caprate diluted with isobutanol to 5% by mass was added to carry out an isocyanuration reaction. When the refractive index of the reaction liquid increased to 0.008, phosphoric acid was added to terminate the reaction. After filtering the reaction solution, unreacted HDI was removed in the same manner as in Synthesis Example 1 to obtain polyisocyanate A'-4. The resulting polyisocyanate A'-4 had a viscosity of 400 mPa·s (25° C.), an NCO content of 20.4% by mass, and an HDI monomer concentration of 0.11% by mass.

[Synthesis Example 5]
(Synthesis of polyisocyanate A'-5)
1000 g of HDI and 78 g of 2-ethylhexanol were charged into the same apparatus as in Synthesis Example 1, and urethanization reaction was carried out at 130° C. for 1 hour while stirring. As an allophanatization catalyst, 0.35 g of a 20% solution of zirconyl 2-ethylhexanoate in mineral spirits was added. After 60 minutes, when the refractive index of the reaction solution increased to 0.0055, a 39% solid content ethanol solution of pyrophosphoric acid (manufactured by Taihei Kagaku Sangyo, trade name "Phosphoric acid (105%)"): 0. 47 g was added to stop the reaction. Then, unreacted HDI was removed in the same manner as in Synthesis Example 1 to obtain polyisocyanate A'-5. The resulting polyisocyanate A'-5 has a viscosity of 100 mPa.s. s (25° C.), an NCO content of 17.4%, and an HDI monomer concentration of 0.11 mass %.

[Synthesis Example 6]
(Synthesis of polyisocyanate A'-6)
1000 g of HDI and 1 g of isobutanol were charged into the same apparatus as in Synthesis Example 1, and the temperature in the reactor was maintained at 80° C. for 2 hours while stirring. Thereafter, after filtering the reaction solution, unreacted HDI was removed in the same manner as in Synthesis Example 1 to obtain polyisocyanate A'-6. The obtained polyisocyanate A'-6 had a viscosity of 600 mPa·s (25° C.), an NCO content of 19.2% by mass, and an HDI monomer concentration of 0.2% by mass.

[Synthesis Example 7]
(Synthesis of polyisocyanate A'-7)
HDI: 1000 g was charged into the same apparatus as in Synthesis Example 1, and the temperature in the reactor was maintained at 80°C for 2 hours while stirring. After that, 1 g of a solution of tetramethylammonium caprate diluted with isobutanol to 5% by mass was added as an isocyanurate-forming catalyst to carry out an isocyanurate-forming reaction. When the refractive index of the reaction solution reached 0.009, phosphoric acid was added to stop the reaction, and the reaction solution was further held at 160° C. for 1 hour. After cooling and filtering the reaction solution, unreacted HDI was removed in the same manner as in Synthesis Example 1 to obtain polyisocyanate A'-7. The resulting polyisocyanate A'-7 had a viscosity of 570 mPa·s (25° C.), an NCO content of 23.2% by mass, and an HDI monomer concentration of 0.11% by mass.

<Production of block polyisocyanate composition>
[Example 1]
(Production of blocked polyisocyanate composition P1-a1)
In the same apparatus as in Synthesis Example 1, polyisocyanate A'-2 obtained in Synthesis Example 2: 67 g, polyether polyol B1-4 (manufactured by AGC Co., Ltd., "Exenol 1020" (trade name), number average molecular weight 1000 ): 33 g, and 2-ethylhexyl phosphate (manufactured by Johoku Chemical Industry Co., Ltd., trade name “JP-508”): 0.01 g. Then, the mixture was subjected to a urethanization reaction at 120° C. for 4 hours while stirring. Then, after the temperature was lowered to 60° C., 27 g of methyl ethyl ketoxime (which may be abbreviated as “MEKO” in this specification) as (C) blocking agent was gradually added. After further stirring for 1 hour, a hindered amine light stabilizer (manufactured by BASF Japan Ltd., trade name "Tinuvin765": 0.1 g, n-butyl acetate as a dilution solvent: 85 g was added, and a block containing a block polyisocyanate was added. A polyisocyanate composition P1-a1 was obtained, which was a transparent liquid and had an effective NCO content of 10.0 mass %.

[Examples 2 to 16, 32 to 47 and Comparative Examples 1, 2, 6]
(Production of blocked polyisocyanate compositions P1-a2 to P1-a16, P1-a32 to P1-a47 and P1-b1, P1-b2, P1-b6)
Block polyisocyanate compositions P1-a2 to P1-a16 containing blocked polyisocyanate were prepared in the same manner as in Example 1 except that the formulations shown in Tables 1 to 3, 6 to 8, and 11 to 12 were used. P1-a32 to P1-a47 and P1-b1, P1-b2, P1-b6 were obtained.

In Tables 1-13, each polyether polyol is as follows. Among these, polyether polyols B1-1 to B1-4 and B1-6 are all (B1) polyether polyols. Polyether polyol B1-5 does not have an oxypropylene group and is not (B1) a polyether polyol.
B1-1: AGC Co., Ltd., "Exenol (registered trademark) 840" (trade name), number average molecular weight 6500
B1-2: AGC Co., Ltd., "Exenol (registered trademark) 230" (trade name), number average molecular weight 3000
B1-3: AGC Co., Ltd., "Exenol (registered trademark) 1030" (trade name), number average molecular weight 1000
B1-4: AGC Co., Ltd., "Exenol (registered trademark) 1020" (trade name), number average molecular weight 1000
B1-5: Hodogaya Chemical Co., Ltd., "PTG1000SN" (trade name), number average molecular weight 1000
B1-6: AGC Co., Ltd., "Exenol (registered trademark) 3020" (trade name), number average molecular weight 3200

In Tables 1-13, "Pz" means "pyrazole" ((C) blocking agent).

[Example 17]
(Production of blocked polyisocyanate composition P1-a17)
In the same apparatus as in Synthesis Example 1, polyisocyanate A'-2 obtained in Synthesis Example 2: 60 g, polyester polyol B2-1 (manufactured by DIC Corporation, "OD-X-2722" (trade name), number average 40 g of molecular weight 2000) and 0.01 g of 2-ethylhexyl phosphate (manufactured by Johoku Chemical Industry Co., Ltd., trade name “JP-508”) were added. Then, the mixture was subjected to a urethanization reaction at 120° C. for 4 hours while stirring. Then, after the temperature was lowered to 60° C., 26 g of methyl ethyl ketoxime (MEKO) was gradually added as (C) a blocking agent. After further stirring for 1 hour, 84 g of n-butyl acetate was added as a diluting solvent to obtain a blocked polyisocyanate composition P1-a17 containing a blocked polyisocyanate. The resulting blocked polyisocyanate composition P1-a17 was a transparent liquid with an effective NCO content of 9.7%.

[Examples 18-31, 48-62 and Comparative Examples 3-5]
(Production of blocked polyisocyanate compositions P1-a18 to P1-a31, P1-a48 to P1-a62 and P1-b3 to P1-b5)
Block polyisocyanate compositions P1-a18 to P1-a31, P1-a48 to P1-a62 and P1-b3 to P1-b5 were obtained.

In Tables 1 to 13, each polyester polyol is as follows. All of these are (B2) polyester polyols.
B2-1: DIC Corporation, "OD-X-2722" (trade name), number average molecular weight 2000
B2-2: DIC Corporation, "OD-X-2542C" (trade name), number average molecular weight 850
B2-3: Daicel Corporation, "PL305" (trade name), number average molecular weight 550
B2-4: DIC Corporation, "OD-X-2733" (trade name), number average molecular weight 300
B2-5: DIC Corporation, "OD-X-2514" (trade name), number average molecular weight 4000
B2-6: DIC Corporation, "OD-X-2234" (trade name), number average molecular weight 3000

[Comparative Example 7]
(Production of polyisocyanate composition P1-b7)
In the same apparatus as in Synthesis Example 1, polyisocyanate A'-3 obtained in Synthesis Example 3: 48 g, polyether polyol B1-2: 52 g, and phosphoric acid 2-ethylhexyl ester (manufactured by Johoku Kagaku Kogyo Co., Ltd., product name “JP-508”): 0.01 g was added. Next, the mixed solution was subjected to a urethanization reaction at 120° C. for 4 hours while stirring, and then a hindered amine light stabilizer (manufactured by BASF Japan Ltd., trade name “Tinuvin 765”: 0.1 g, n-butyl acetate as a diluting solvent: 67 g was added to obtain a polyisocyanate composition P1-b7, which was a transparent liquid with an NCO content of 7.7% by mass.

[Comparative Examples 8 and 9]
(Production of polyisocyanate compositions P1-b8 and P1-b9)
Polyisocyanate compositions P1-b8 and P1-b9 were obtained in the same manner as in Comparative Example 7 except that the formulations shown in Table 12 were used.

[Comparative Example 10]
(Production of polyisocyanate composition P1-b10)
In the same apparatus as in Synthesis Example 1, polyisocyanate A'-2 obtained in Synthesis Example 2: 60 g, polyester polyol B2-1: 40 g, and phosphoric acid 2-ethylhexyl ester (manufactured by Johoku Kagaku Kogyo Co., Ltd., product name “JP-508”): 0.01 g was added. Then, the mixed solution was subjected to a urethanization reaction at 120° C. for 4 hours with stirring, and then 67 g of n-butyl acetate was added as a diluting solvent to obtain polyisocyanate composition P1-b10. The obtained polyisocyanate composition P1-b10 was a transparent liquid and had an NCO content of 12.2% by mass.

[Comparative Examples 11 and 12]
(Production of polyisocyanate compositions P1-b11 and P1-b12)
Polyisocyanate compositions P1-b11 and P1-b12 were obtained in the same manner as in Comparative Example 10, except that the formulations shown in Table 13 were used.

Using each block polyisocyanate composition or each polyisocyanate composition obtained, the pot life of the coating composition, and the water resistance, weather resistance, toughness, hardness and resistance of the coating film are measured by the method described above. Impact resistance was evaluated. The results are shown in Tables 1-13. In addition, in Comparative Examples 1 to 12 in Tables 11 to 13, polyisocyanate compositions are described in the column of "blocked polyisocyanate composition".

As shown in Tables 1 to 11, by using the blocked polyisocyanate compositions P1-a1 to P1-a62 (Examples 1 to 62), coating compositions with a long pot life and a long pot life were obtained. . Moreover, by using these blocked polyisocyanate compositions, coating films excellent in water resistance, weather resistance, toughness, hardness and impact resistance were obtained. In these block polyisocyanate compositions, the number average molecular weight of polyether polyols B1-1 to B1-4 and B1-6 satisfies the condition of 400 to 10000 (more specifically 1000 to 6500), or , The condition that the number average molecular weight of the polyester polyols B2-1 to B2-6 is 250 or more and 5000 or less (more specifically 300 or more and 4000 or less), and the F/E is 0.10 or more and 11.00 or less ( More specifically, 0.16 or more and 10.86 or less) was satisfied.

In the blocked polyisocyanate compositions P1-a1 to P1-a62 (Examples 1 to 62), the condition that D/E is 0.01 or more and 3.00 or less (more specifically, 0.02 or more and 2.00). 92 or less) and fulfilled the condition that F/(D+F) is 0.35 or more and 0.99 or less.

Among the block polyisocyanate compositions P1-a1 to P1-a62 (Examples 1 to 62), the number average molecular weight of the polyether polyol is 500 or more and 7000 or less, or the number average molecular weight of the polyester polyol is 500. Those that satisfy the condition of 5000 or more and F/E of 0.15 or more and 7.00 or less have a longer pot life of the coating composition and the water resistance, weather resistance and toughness of the coating film. , in terms of higher hardness and impact resistance.
Furthermore, in addition to these conditions, paints that satisfy the condition that D/E is 0.01 or more and 2.00 or less or that F/(D+F) is 0.50 or more and 0.99 or less are paints. It was further excellent in that the pot life of the composition was extended and the water resistance, weather resistance, toughness, hardness and impact resistance of the coating film were increased.

Among the block polyisocyanate compositions P1-a1 to P1-a62 (Examples 1 to 62), the number average molecular weight of the polyether polyol is 500 or more and 3500 or less, or the number average molecular weight of the polyester polyol is 500. Those satisfying the condition of 3500 or less and F/E of 0.25 or more and 2.50 or less have a longer pot life of the coating composition and the water resistance, weather resistance and toughness of the coating film. , was particularly excellent in terms of increasing hardness and impact resistance.
Furthermore, in addition to these conditions, paints that satisfy the condition that D/E is 0.01 or more and 0.90 or less or that F/(D+F) is 0.70 or more and 0.99 or less are paints. It was most excellent in that the pot life of the composition was extended and the water resistance, weather resistance, toughness, hardness and impact resistance of the coating film were increased.

On the other hand, polyisocyanate compositions P1-b1 to P1-b12 (Comparative Examples 1 to 12) all have a long pot life and a long pot life, and water resistance, It was not excellent in all of the points that a coating film excellent in weather resistance, toughness, hardness and impact resistance can be obtained.

A comparison of the blocked polyisocyanate compositions P1-a1 to P1-a62 (Examples 1 to 62) and the polyisocyanate compositions P1-b7 to P1-b12 (Comparative Examples 7 to 12) revealed that some isocyanate groups It was confirmed that a coating film with excellent impact resistance was obtained by using (C) a blocked polyisocyanate blocked by a blocking agent and into which structural units derived from the (C) blocking agent were introduced.

According to the blocked polyisocyanate composition of the present embodiment, a coating film having excellent water resistance, weather resistance, toughness, hardness and impact resistance, and a coating composition having a long pot life for forming the coating film can be obtained. can provide. The blocked polyisocyanate composition of this embodiment can be used as a raw material for paints, inks, adhesives, casting materials, elastomers, foams, and plastic materials. The coating composition of the present embodiment is suitable for architectural coatings, heavy-duty anti-corrosion coatings, automotive coatings, information appliance coatings, and information equipment coatings such as personal computers and mobile phones.

Claims (7)

(A) at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates;
(B1) a polyether-based polyol having an oxypropylene group with a number average molecular weight of 400 or more and 10,000 or less; at least one polyol selected from the group consisting of polyester-based polyols;
(C) a blocking agent;
containing a blocked polyisocyanate obtained from
having an allophanate group, an isocyanurate group and a urethane group,
A block wherein the ratio F/E of the F to the E is 0.10 or more and 11.00 or less, where E is the number of moles of the isocyanurate group and F is the number of moles of the urethane group before blocking. Polyisocyanate composition. 2. The blocked polyisocyanate composition according to claim 1, wherein the ratio D/E of said D to said E is 0.01 or more and 3.00 or less, where D is the number of moles of said allophanate groups. 3. The blocked polyisocyanate composition according to claim 2, wherein the ratio F/(D+F) of said F to the sum of said D and said F is 0.35 or more and 0.99 or less. a polyol having a hydroxyl value of 5 mgKOH/g or more and 200 mgKOH/g or less;
The blocked polyisocyanate composition according to any one of claims 1 to 3;
A coating composition comprising: 5. The coating composition according to claim 4, which is used for coating metals or plastics. 6. The coating composition according to claim 4 or 5, which is used as a paint for building structures, automobile bodies, metal parts for automobiles, plastic parts for automobiles, metal parts for home information appliances, or plastic parts for home information appliances. A coating film obtained by curing the coating composition according to any one of claims 4 to 6.