JP6031734B2 - Polyisocyanate composition using allophanate / isocyanurate forming catalyst, method for producing the composition, and two-component coating composition using the composition - Google Patents

Description

  The present invention relates to a polyisocyanate composition using an allophanate / isocyanurate-forming catalyst, a method for producing the composition, and a two-component coating composition using the composition.

Two-component curable urethane coatings that use polyisocyanate as a component provide coatings with excellent weather resistance and abrasion resistance. Conventionally, coating of outdoor substrates such as buildings and civil engineering structures, It is used for repair and plastic coating.
Due to the high polarity of polyisocyanate, these paints generally contain strong solvents such as aromatic hydrocarbon solvents such as toluene and xylene, and ester solvents such as butyl acetate, that is, solvents with strong dissolving power. It was used.

  Since these strong solvents have a strong odor, they tend to be avoided in recent years in terms of improving the working environment and reducing the burden on the global environment. In addition, when repairing or repainting by repainting from the top of the old paint film, if the solvent for repair contains a strong solvent with high dissolving power, the old paint film will swell or dissolve, and the old paint The need to repair even the coating film has arisen. As a result, problems such as enlargement and complication of painting work, increase in painting cost, and extension of the work period may occur.

  Against this background, in recent years, development of polyisocyanates that are easily soluble in low-polar organic solvents has been promoted. As a polyisocyanate excellent in dilutability in a low polar organic solvent, a polyisocyanate compound obtained by reacting an aliphatic diisocyanate and a polyol having a dilutability in a low polar organic solvent of 100% or more has been proposed. The polyisocyanate compound thus obtained is excellent in extensibility of the coating film and dissolution in an aliphatic, alicyclic and / or aromatic hydrocarbon organic solvent having an aniline point in the range of 10 to 70 ° C. (For example, refer to Patent Document 1).

  In addition, as a polyisocyanate having excellent solubility in a low-polar organic solvent and compatibility with a silicate compound, a predetermined allophanate group from an aliphatic and / or alicyclic diisocyanate and a monoalcohol having 1 to 20 carbon atoms. A polyisocyanate compound having a molar ratio of / isocyanurate groups and a specific molecular weight range has been proposed. The polyisocyanate compound thus obtained is excellent in extensibility of the coating film and dissolution in an aliphatic, alicyclic and / or aromatic hydrocarbon organic solvent having an aniline point in the range of 10 to 70 ° C. (For example, see Patent Document 2).

  Moreover, by using tin octylate as a polyisocyanate having improved solubility in a low-polar organic solvent such that the aniline point exceeds 70 ° C., aliphatic diisocyanate, a monoalcohol having 11 or more carbon atoms, and a catalyst, A polyisocyanate compound in which an allophanate group and an isocyanurate group are simultaneously generated has been proposed (see, for example, Patent Document 3).

JP-A-8-198928 JP 2008-24828 A JP 2010-150455 A

  However, conventional polyisocyanate compounds often have low storage stability at low temperatures, and are often insufficiently soluble in low-polarity organic solvents with low solubility, resulting in poor appearance and weather resistance of the coating film. There was a risk of problems such as lowering of

  Further, the hydrolyzable chlorine contained in the organic diisocyanate raw material may react with the catalyst to generate a protonic acid, which may cause reaction inhibition. This reaction inhibition is particularly remarkable for the isocyanurate-forming reaction. When trying to obtain a polyisocyanate compound containing allophanate groups and isocyanurate groups, most of the products obtained are allophanate group-containing polyisocyanate compounds. It was very difficult to obtain the desired product. Moreover, even when a polyisocyanate compound containing both linking groups is obtained, it is a mixture of an allophanate group-containing polyisocyanate compound and an isocyanurate group-containing polyisocyanate compound, and a decrease in solubility in a low-polar organic solvent, Problems remain in productivity such as a decrease in storage stability due to the addition of a catalyst and a decrease in workability such as an increase in reaction time and catalyst adjustment due to a variation in reactivity.

  Here, hydrolyzable chlorine means that when an organic diisocyanate is obtained by reaction of an amine compound and phosgene, it is contained in an organic diisocyanate raw material in an amount of about 0.001 to 1% by mass as an impurity, and hydrochloric acid is generated by hydrolysis. It is a general term for substances to be used. The main hydrolyzable chlorine is a hydrochloride of a carbamoyl chloride compound in which hydrochloric acid is added to an isocyanate group.

  The present invention has been made based on the above circumstances, and by using a specific allophanate / isocyanurate catalyst, a polyisocyanate composition excellent in storage stability at low temperatures and solubility in a low polar organic solvent. It is providing the two-component coating composition excellent in recoat property and film physical property while providing a thing and its manufacturing method.

  As a result of repeated investigations, the present inventors use organic diisocyanate having a high hydrolyzable chlorine concentration as a raw material by using a compound of a specific oxidized carboxylic acid metal salt as an allophanate isocyanurate catalyst. Even in this case, the present inventors have found that a polyisocyanate composition containing both bonding groups in one molecule can be obtained without inhibiting the allophanatization reaction and the isocyanurate formation reaction.

The outline of the present invention is as follows.
[1] A polyisocyanate composition obtained from a reaction between an organic diisocyanate (B) and a monoalcohol (C) in the presence of an allophanate / isocyanurate-forming catalyst (A) represented by the general formula (1). The polyisocyanate characterized in that the tetravalent metal content of the allophanate / isocyanurate conversion catalyst (A) is calculated based on the iodine solution titration method and is at least 10% by mass with respect to the total metal content. Composition.

(M in the general formula (1) represents a tetravalent metal selected from tin and zinc. R represents a bonding group selected from an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group, and a phenyl group. )

  [2] In the presence of the allophanate isocyanurate-forming catalyst (A) according to [1], the organic diisocyanate (B) and the monoalcohol (C) are reacted to form an allophanate group, and isocyanurate immediately. A polyisocyanate composition comprising a linking group that forms a group.

[3] The polyisocyanate composition contains allophanate groups and isocyanurate groups in a molar ratio of allophanate groups / isocyanurate groups = 80/20 to 30/70 , either [1] or [ 2] The polyisocyanate composition described in 1.

[4] The organic diisocyanate (B) is an aliphatic or alicyclic diisocyanate, and the alkyl group of the monoalcohol (C) has 3 to 20 carbon atoms , either [1] or [ 2] polyisocyanate composition according to any.

[5] A two-component coating composition comprising the polyisocyanate composition according to any one of [1] to [4] and a polyol (D).

[6] An organic solvent having a polyisocyanate composition according to any one of [1] to [4] , a polyol (D), an aniline point according to JIS K 2256, or a mixed aniline point of 5 to 100 ° C. A two-component coating composition comprising E).

  According to the polyisocyanate composition using the allophanate / isocyanurate conversion catalyst of the present invention, the method for producing the composition, and the two-component coating composition using the composition, a specific allophanate / isocyanurate conversion catalyst is used. Even if it is a case where organic diisocyanate with high hydrolyzable chlorine concentration is used as a raw material, it does not inhibit the allophanate reaction and isocyanurate reaction, and contains both linking groups in one molecule. An isocyanate composition is obtained, and the two-component coating composition containing the polyisocyanate composition and the polyol is excellent in solubility in a low-polar organic solvent, and therefore erodes the undercoat layer when the coating is repeatedly applied. In addition, recoatability and coating film properties are excellent.

The allophanate / isocyanurate catalyst (A) used in the polyisocyanate composition of the present invention is converted to isocyanurate immediately after allophanate formation to produce allophanate groups and isocyanurate groups in the polyisocyanate composition. And a compound represented by the general formula (1).
This allophanate / isocyanurate conversion catalyst contains tetravalent metals that cannot be oxidized in the molecule, thereby suppressing the decomposition of hydrolyzable chlorine and reducing the production of protonic acids that are the cause of reaction inhibition. . In addition, since this catalyst contains a tetravalent metal in the molecule, the reaction is not delayed even when the protonic acid is in a high state.

The allophanate isocyanurate-forming catalyst (A) is a carboxylic acid metal salt represented by the general formula (1), and M is one kind of tetravalent metal selected from tin and zinc . In the case of other metals, one reaction of allophanate or isocyanurate proceeds selectively to obtain a polyisocyanate composition containing both allophanate groups and isocyanurate groups in one molecule. Is difficult.
R in the side chain is a linking group selected from an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group, and a phenyl group. In the case of other side chains, the solubility of the catalyst in the low polarity organic solvent is lowered, and there is a possibility that precipitates are formed.
Specific examples of carboxylic acids include acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, heptylic acid, octylic acid, pelargonic acid, capric acid, lauric acid, myristic acid, palmitic acid, margaric acid, stearic acid, Saturated aliphatic carboxylic acids such as velcrostearic acid, aragdic acid, 2-ethylhexanoic acid, saturated monocyclic carboxylic acids such as cyclopropyl carboxylic acid, cyclobutyl carboxylic acid, cyclopentyl carboxylic acid, cyclohexyl carboxylic acid, bicyclo (4.4 0.0) saturated polycyclic carboxylic acids such as decane-2-carboxylic acid, unsaturated fatty carboxylic acids such as palmitoleic acid, oleic acid, linoleic acid, linolenic acid, vaccenic acid, eleostearic acid, arachidonic acid, diphenylacetic acid Aromatic aliphatic carboxylic acids such as benzoic acid and toluic acid Bonn acid and the like.
The allophanate isocyanurate-forming catalyst (A) can be used alone or in combination of two or more.

The tetravalent metal content of the allophanate / isocyanurate conversion catalyst (A) is calculated based on the iodine solution titration method, and is preferably at least 10% by mass based on the total metal content. In addition, the metal content measurement method can also perform quantification by weight change (determined by calculation from the increase amount accompanying oxidation, with the atomic weight of oxygen being 16). Furthermore, the quantification of the total metal content can also be measured using inductively coupled plasma emission spectroscopy (ICP analysis).
If the tetravalent metal content of the allophanate / isocyanurate conversion catalyst is less than the lower limit, hydrolyzable chlorine is decomposed to produce protonic acid, which causes reaction inhibition and the desired product is obtained. There is no fear.

Here, as a measuring method of the iodine solution titration method, the tetravalent metal content can be calculated by obtaining the total metal content and the divalent metal content by the following operation.
<Measurement method of total metal content: A (mass%)>
(1) About 0.5 g of a sample is weighed into 500 ml of Erlenmeyer flask, and 100 ml of hydrochloric acid (1 + 1), 5 g of sodium phosphinate, and 1 ml of saturated mercuric chloride solution are added.
(2) A Geckel valve is attached to the Erlenmeyer flask, sodium hydrogen carbonate and pure water are added, the air is shut off, heated on a hot plate for 40 minutes, and then cooled to 20 ° C. or lower.
(3) Add 2 ml of starch solution, titrate with 0.05 mol / l iodine solution, and calculate the total metal content from the titration with the end point when the iodine starch reaction is colored black purple.
<Measurement method of divalent metal content: B (mass%)>
(1) Add a marble piece, 2 g of sodium bicarbonate, and 20 ml of pure water to a 300 ml Erlenmeyer flask.
(2) Add 30 ml of hydrochloric acid (1 + 3) to this, and add about 0.5 g of a pre-weighed sample.
(3) Titrate with 0.05 mol / l iodine solution, and when the end point is near, add 2 ml of starch solution, and when the end point is colored black-purple of iodine starch reaction, the end point is the divalent metal content from titration Is calculated.
<Calculation of tetravalent metal content: C (mass%)>
C = (A−B) / A × 100
(1) A: Total metal content (% by mass)
(2) B: Divalent metal content (mass%)
(3) C: Tetravalent metal content (% by mass)

  The allophanate isocyanurate-forming catalyst (A) is prepared by oxidizing the carboxylic acid metal salt represented by the general formula (2). In addition, as a method for the oxidation treatment, a known oxidizing agent can be used. However, in terms of safety, moderate oxidation ability, no purification is required, and synthesis can be performed with a simple apparatus, it can be performed in an oxygen atmosphere. A heat treatment method or an ozone treatment method using a commercially available ozone generator is selected.

(M in the general formula (2) represents a divalent metal selected from tin and zinc. R represents a bonding group selected from an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group, and a phenyl group. )

  In addition, the carboxylic acid metal salt is not limited to the monodentate coordination of the general formula (2), but is a bidentate coordination represented by the general formula (3) or the general formula (4), or a combination of the monodentate coordination and the bidentate coordination. Those having a combined state of are also included.

(M in general formula (3) and general formula (4) represents a divalent metal selected from tin and zinc. R represents an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group, and a phenyl group. Indicates the selected linking group.)

  The allophanate isocyanurate catalyst (A) used for the production of the polyisocyanate composition of the present invention is suitable for producing both allophanate group and isocyanurate group bonding groups in one molecule of the polyisocyanate composition. is there. By containing both linking groups in one molecule, the storage stability at low temperature, improved weather resistance, and low compared to the conventional mixture of allophanate group-containing polyisocyanate compound and isocyanurate group-containing polyisocyanate compound. The solubility with respect to a polar organic solvent can be improved.

  A polyisocyanate composition containing both allophanate group and isocyanurate group bonding group in one molecule comprises an organic diisocyanate (B), a monoalcohol (C), and an allophanate isocyanurate-forming catalyst (A). The polyisocyanate composition containing both linking groups in one molecule can be obtained by generating allophanate groups by the reaction of and immediately generating isocyanurate groups.

  Here, the organic diisocyanate (B) used is not particularly limited, and examples thereof include aromatic diisocyanates, aliphatic diisocyanates, alicyclic diisocyanates, and araliphatic diisocyanates. The above can be used together.

<Aromatic diisocyanate>
Specific examples of the aromatic diisocyanate include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 2,4-tolylene diisocyanate / 2,6-tolylene diisocyanate mixture, m-xylylene diisocyanate, p- Xylylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate / 4,4'-diphenylmethane diisocyanate mixture, 4,4'-diphenyl ether diisocyanate, 2-nitrodiphenyl- 4,4'-diisocyanate, 2,2'-diphenylpropane-4,4'-diisocyanate, 3,3'-dimethyldiphenylmethane-4,4'-diisocyanate, 4,4'-diphenylpropylene Examples include lopan diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, naphthylene-1,4-diisocyanate, naphthylene-1,5-diisocyanate, 3,3'-dimethoxydiphenyl-4,4'-diisocyanate.

<Aliphatic diisocyanate>
Specific examples of the aliphatic isocyanate include hexamethylene diisocyanate, tetramethylene diisocyanate, 2-methyl-pentane-1,5-diisocyanate, 3-methyl-pentane-1,5-diisocyanate, lysine diisocyanate, and trioxyethylene diisocyanate. Can be mentioned.

<Alicyclic diisocyanate>
Specific examples of the alicyclic diisocyanate include isophorone diisocyanate, cyclohexyl diisocyanate, hydrogenated diphenylmethane diisocyanate, norbornane diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated xylene diisocyanate, hydrogenated tetramethylxylene diisocyanate and the like.

<Aromatic aliphatic diisocyanate>
Specific examples of the araliphatic diisocyanate include 1,3- or 1,4-xylylene diisocyanate or a mixture thereof, 1,3- or 1,4-bis (1-isocyanato-1-methylethyl) benzene or a mixture thereof. , Ω, ω′-diisocyanato-1,4-diethylbenzene and the like.

<(C) Monoalcohol>
The monoalcohol (C) used in the polyisocyanate composition is not particularly limited, and 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, 1-tridecanol, 2-tridecanol, Examples include 2-octyldodecanol, pentadecanol, palmityl alcohol, stearyl alcohol, cyclopentanol, cyclohexanol, methylcyclohexanol, trimethylcyclohexanol, and the like. These may be used alone or in combination of two or more. That.
Among these monoalcohols, 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, 1-tridecanol, 2-tridecanol, and 2-octyldodecanol are particularly excellent in solubility in low-polar organic solvents. More preferable. When the number of carbon atoms of the alkyl group exceeds the upper limit, the crystallinity is increased, so that the storage stability is lowered, which is not preferable. Moreover, when it has coupling | bonding groups other than an alkyl group, the solubility with respect to a low polar organic solvent falls and it is unpreferable.

Next, the specific manufacturing method of a polyisocyanate composition is demonstrated.
In the first step, an organic diisocyanate (B) and a monoalcohol (C) are charged in an excess amount with respect to the hydroxyl group, and in the presence or absence of an organic solvent at 20 to 120 ° C. Isocyanate group-terminated prepolymer I is produced by urethanization reaction. Here, as a standard of the urethanization reaction, the presence or absence of completion is judged by the isocyanate group content and the refractive index increase value by the neutralization titration method.
In the second step, the isocyanate group-terminated prepolymer I is charged with an allophanate / isocyanurate-forming catalyst (A) and subjected to nuclear magnetic resonance spectroscopy (hereinafter referred to as NMR) and gel permeation (hereinafter referred to as GPC). Then, allophanate formation is performed at 70 to 150 ° C. until the desired isocyanate group content and molecular weight are reached, and then isocyanurate conversion is immediately performed to produce isocyanate group-terminated prepolymer II.
In the third step, the reaction is stopped by adding a reaction terminator to the isocyanate group-terminated prepolymer II.
In these first to third steps, the reaction is allowed to proceed under nitrogen gas or a dry air stream.
In the fourth step, the isocyanate group-terminated prepolymer II is removed by thin film distillation or solvent extraction until the content of free organic diisocyanate (B) is less than 1% by mass.

  Here, the “amount of isocyanate group in excess” in the first step means that the molar ratio of the isocyanate group of the organic diisocyanate to the hydroxyl group of the monool is 6 to 6 when R = isocyanate group / hydroxyl group. It is preferable to charge so that it may become 40, More preferably, it is preferable to charge so that it may become R = 7-30. When the amount is less than the lower limit, the amount of the polyisocyanate composition having a higher molecular weight than that of the target product is increased, which may increase the viscosity or decrease the solubility in the low polarity organic solvent. When the upper limit is exceeded, the amount of urethane group-containing polyisocyanate that is a precursor of the polyisocyanate composition increases, resulting in a decrease in coating film properties due to a decrease in the number of average functional groups, and a decrease in productivity and yield. There is a risk of inviting.

  Moreover, the reaction temperature of a urethanation reaction is 20-120 degreeC, Preferably it is 50-100 degreeC. In the urethanization reaction, a known urethanization catalyst can be used. Specifically, organic metal compounds such as dibutyltin diacetate, dibutyltin dilaurate and dioctyltin dilaurate, organic amines such as triethylenediamine and triethylamine, and salts thereof are selected and used. These catalysts can be used alone or in combination of two or more.

  The reaction time of the urethanization reaction varies depending on the presence or absence of the catalyst, the type, and the temperature, but is generally within 10 hours, preferably 1 to 5 hours is sufficient.

The amount of the allophanate / isocyanurate-forming catalyst (A) used in the second step is preferably 0.001 to 1.0% by mass relative to the total mass of the organic diisocyanate (B) and the monoalcohol (C). 0.005-0.1 mass% is more preferable.
If it is less than the lower limit, the allophanate reaction and isocyanurate reaction do not proceed sufficiently, and the amount of urethane group-containing polyisocyanate that is a precursor of the polyisocyanate composition increases, resulting in a decrease in the number of average functional groups. There is a risk that the physical properties of the coating film will be lowered, and the productivity and yield will be reduced. When the upper limit is exceeded, the amount of polyisocyanate composition having a molecular weight higher than that of the target product is increased, leading to an increase in viscosity, a decrease in solubility in low-polar organic solvents, and a decrease in reactivity control. There is a fear.

  In addition, the reaction temperature of the allophanate reaction and the isocyanurate reaction is 70 to 150 ° C, preferably 80 to 130 ° C.

  Moreover, the molar ratio of the allophanate group and isocyanurate group contained in the polyisocyanate composition to be obtained is adjusted so that the allophanate group / isocyanurate group is in the range of 80/20 to 30/70 by appropriately adjusting the reaction time. It is possible. When the molar ratio of isocyanurate groups is less than the lower limit, the physical properties of the coating film may be lowered. Moreover, when exceeding an upper limit, there exists a possibility of causing the fall of the solubility with respect to a low polar organic solvent, and the fall of adhesiveness.

Moreover, in manufacture of a polyisocyanate composition, the method of reacting without including an organic solvent etc., and the method of reacting in presence of an organic solvent are suitably selected.
When the reaction is performed in the presence of an organic solvent, an organic solvent that does not affect the reaction can be used. Specific examples of the organic solvent include aliphatic hydrocarbons such as octane, alicyclic hydrocarbons such as cyclohexane and methylcyclohexane, ketones such as methyl isobutyl ketone and cyclohexanone, esters such as butyl acetate and isobutyl acetate, Ethylene glycol ethyl ether acetate, propylene glycol monomethyl ether acetate, 3-methyl-3-methoxybutyl acetate, glycol ether esters such as ethyl-3-ethoxypropionate, ethers such as dioxane, methylene iodide, monochlorobenzene, etc. And polar aprotic solvents such as N-methylpyrrolidone, dimethylformamide, dimethylacetamide, dimethylsulfoxide, hexamethylphosphonilamide, and the like. These solvents can be used alone or in combination of two or more.
The organic solvent used in the reaction is removed simultaneously with the removal of the free organic diisocyanate (B) in the fourth step.

  The reaction terminator in the third step has an action of deactivating the activity of the catalyst. Specifically, inorganic acids such as phosphoric acid and hydrochloric acid, organic acids having a sulfonic acid group, a sulfamic acid group, and the like, and these Known compounds such as esters and acyl halides are used. These reaction terminators can be used alone or in combination of two or more. In addition, the addition time is preferably a rapid addition after completion of the reaction.

  The amount of the reaction terminator added varies depending on the kind of the reaction terminator and the catalyst, but is preferably 0.5 to 10 equivalents, and particularly preferably 0.8 to 5.0 equivalents of the catalyst. When there are few reaction terminators, the storage stability of the obtained polyisocyanate composition tends to decrease, and when it is too much, the polyisocyanate composition may be colored.

  In the purification step of the fourth step, free unreacted organic diisocyanate (B) present in the reaction mixture is removed, for example, by thin film distillation at 120 to 150 ° C. under high vacuum of 10 to 100 Pa. The residual content is reduced to 1.0 mass% or less by an extraction method using an organic solvent. In addition, when the residual content rate of organic diisocyanate exceeds an upper limit, there exists a possibility of causing the fall of an odor and storage stability.

  The polyisocyanate composition obtained by purification can be made into a blocked isocyanate by using a known blocking agent for the purpose of extending the pot life or making the coating composition into one component. As a result, the blocked polyisocyanate is inactive at room temperature, but when heated, the blocking agent dissociates, and the isocyanate group is activated again, thereby causing a potential function to react with the active hydrogen group. Can be added.

  The polyisocyanate composition thus obtained has an average functional group number determined from the number average molecular weight obtained from GPC analysis in the range of 2.0 to 5.0. If it is less than the lower limit, the crosslinking density may decrease, and the solvent resistance and physical properties of the coating film may decrease. Moreover, when exceeding an upper limit, there exists a possibility of causing the fall of the solubility with respect to a low polar organic solvent, and the fall of adhesiveness.

  Moreover, the number average molecular weight of a polyisocyanate composition is 500-3000, Preferably it is 500-2500, More preferably, it is 500-2000. If it is less than the lower limit, the adhesion may be reduced, and if it exceeds the upper limit, the solubility in a low-polar organic solvent may be lowered or the adhesion may be lowered.

  The viscosity of the polyisocyanate composition is not particularly limited, but is preferably 100 to 2000 mPa · s at 25 ° C., more preferably 500 to 1500 mPa · s. When the upper limit is exceeded, the viscosity of the two-component coating composition increases, and it may be difficult to handle.

  Moreover, when polyisocyanate composition obtained by a series of reaction mix | blends polyol (D) and the organic solvent (E) whose aniline point or mixed aniline point is 5-100 degreeC, when overcoating. The two-layer coating composition is excellent in recoatability without eroding the underlying layer, and further in solvent resistance and physical properties of the coating film.

  Here, the polyol (D) used in the two-component coating composition of the present invention is not particularly limited, but is a compound containing an active hydrogen group as a reactive group of an isocyanate group, and a polyester polyol. , Polyether polyols, polycarbonate polyols, polyolefin polyols, acrylic polyols, silicone polyols, castor oil-based polyols, fluorine-based polyols, transesterification products of two or more polyols, and hydroxyl-terminated prepolymers urethanated with polyisocyanates, etc. These are preferably used, and these can be used as one kind or a mixture of two or more kinds.

<Polyester polyol>
Specific examples of polyester polyols include phthalic acid, isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, succinic acid, tartaric acid, oxalic acid, malonic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, glutaconic acid, azelaic acid, Dicarboxylic acids such as sebacic acid, 1,4-cyclohexyl dicarboxylic acid, α-hydromuconic acid, β-hydromuconic acid, α-butyl-α-ethylglutaric acid, α, β-diethylsuccinic acid, maleic acid, fumaric acid, etc. Or one or more of these anhydrides and the like, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1, -Nonanediol, 3-methyl-1,5-pentanediol, 3,3-dimethylolheptane, diethylene glycol, dipropylene glycol, neopentyl glycol, cyclohexane-1,4-diol, cyclohexane-1,4-dimethanol, One or more low molecular weight polyols having a molecular weight of 500 or less, such as dimer acid diol, bisphenol A ethylene oxide and propylene oxide adducts, bis (β-hydroxyethyl) benzene, xylylene glycol, glycerin, trimethylolpropane, pentaerythritol And those obtained from the polycondensation reaction. Also, lactone polyester polyols obtained from ring-opening polymerization of cyclic ester (so-called lactone) monomers such as ε-caprolactone, alkyl-substituted ε-caprolactone, δ-valerolactone, and alkyl-substituted δ-valerolactone can be exemplified. Furthermore, a polyester-amide polyol obtained by replacing a part of the low molecular polyol with a low molecular polyamine such as hexamethylene diamine, isophorone diamine, monoethanolamine, or a low molecular amino alcohol can also be used.

<Polyether polyol>
Specific examples of the polyether polyol include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, , 5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 3-methyl-1,5-pentanediol, 3,3-dimethylolheptane, diethylene glycol, dipropylene Glycol, neopentyl glycol, cyclohexane-1,4-diol, cyclohexane-1,4-dimethanol, dimer acid diol, bisphenol A, bis (β-hydroxyethyl) benzene, xylylene glycol, glycerin, trimethylolpropane, penta Small molecules such as erythritol Initiates compounds having 2 or more, preferably 2-3 active hydrogen groups such as diols or low molecular weight polyamines such as ethylenediamine, propylenediamine, toluenediamine, metaphenylenediamine, diphenylmethanediamine, xylylenediamine, etc. As an agent, polyether polyols obtained by addition polymerization of alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, etc., or alkyl glycidyl ethers such as methyl glycidyl ether, aryl glycidyl ethers such as phenyl glycidyl ether And polyether polyols obtained by ring-opening polymerization of cyclic ether monomers such as tetrahydrofuran.

<Polycarbonate polyol>
Specific examples of the polycarbonate polyol include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1, 5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 3-methyl-1,5-pentanediol, 3,3-dimethylolheptane, diethylene glycol, dipropylene glycol , Neopentyl glycol, diethylene glycol, dipropylene glycol, cyclohexane-1,4-diol, cyclohexane-1,4-dimethanol, dimer acid diol, ethylene oxide or propylene oxide adduct of bisphenol A, bis (β-hydroxyethyl) One or more kinds of low-molecular polyols such as benzene, xylylene glycol, glycerin, trimethylolpropane, pentaerythritol, dialkyl carbonates such as dimethyl carbonate and diethyl carbonate, alkylene carbonates such as ethylene carbonate and propylene carbonate, diphenyl carbonate, Examples thereof include those obtained from dealcoholization reaction and dephenol reaction with diaryl carbonates such as dinaphthyl carbonate, dianthryl carbonate, diphenanthryl carbonate, diindanyl carbonate and tetrahydronaphthyl carbonate.
Moreover, the polyol obtained by transesterification of polycarbonate polyol, polyester polyol, and low molecular polyol can also be used suitably.

<Polyolefin polyol>
Specific examples of the polyolefin polyol include polybutadiene having two or more hydroxyl groups, hydrogenated polybutadiene, polyisoprene, and hydrogenated polyisoprene.

<Acrylic polyol>
Examples of the acrylic polyol include acrylic acid ester and / or methacrylic acid ester (hereinafter referred to as (meth) acrylic acid ester), and acrylic acid hydroxy compound or / and methacrylic acid having at least one hydroxyl group in the molecule that can be a reaction point. Examples thereof include those obtained by copolymerizing an acrylic monomer using a thermal compound, a light energy such as an ultraviolet ray or an electron beam, and the like with a hydroxy compound (hereinafter referred to as a (meth) acrylic acid hydroxy compound) and a polymerization initiator.

<(Meth) acrylic acid ester>
Specific examples of (meth) acrylic acid esters include alkyl esters having 1 to 20 carbon atoms. Specific examples of such (meth) acrylate esters include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, pentyl (meth) acrylate, (Meth) such as hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate Acrylic acid alkyl ester; (meth) acrylic acid ester such as cyclohexyl (meth) acrylate with cycloaliphatic alcohol; (meth) acrylic acid aryl ester such as phenyl (meth) acrylate and benzyl (meth) acrylate Can be mentioned. Such (meth) acrylic acid esters can be used singly or in combination of two or more.

<(Meth) acrylic acid hydroxy compound>
Specific examples of the (meth) acrylic acid hydroxy compound have at least one hydroxyl group in the molecule that can be a reaction point with the polyisocyanate (B), specifically, 2-hydroxyethyl acrylate, Acrylic acid hydroxy compounds such as 2-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, 3-hydroxy-2,2-dimethylpropyl acrylate, and pentaerythritol triacrylate are listed. Moreover, methacrylic acid hydroxy compounds, such as 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 4-hydroxybutyl methacrylate, 3-hydroxy-2,2-dimethylpropyl methacrylate, and pentaerythritol trimethacrylate, are mentioned. These acrylic acid hydroxy compounds and / or methacrylic acid hydroxy compounds can be used singly or in combination of two or more.

<Silicone polyol>
Specific examples of the silicone polyol include a vinyl group-containing silicone compound obtained by polymerizing γ-methacryloxypropyltrimethoxysilane and the like, and α, ω-dihydroxypolydimethylsiloxane having at least one terminal hydroxyl group in the molecule, α, Mention may be made of polysiloxanes such as ω-dihydroxypolydiphenylsiloxane.

<Castor oil-based polyol>
Specific examples of the castor oil-based polyol include linear or branched polyester polyols obtained by a reaction between a castor oil fatty acid and a polyol. Dehydrated castor oil, partially dehydrated castor oil partially dehydrated, and hydrogenated castor oil added with hydrogen can also be used.

<Fluorine-based polyol>
A specific example of the fluorine-based polyol is a linear or branched polyol obtained by a copolymerization reaction using a fluorine-containing monomer and a monomer having a hydroxy group as essential components. Here, the fluorine-containing monomer is preferably a fluoroolefin, for example, tetrafluoroethylene, chlorotrifluoroethylene, trichlorofluoroethylene, hexafluoropropylene, vinylidene fluoride, vinyl fluoride, trifluoromethyl trifluoroethylene. Is mentioned. Examples of the monomer having a hydroxyl group include hydroxyalkyl vinyl ethers such as hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether and cyclohexanediol monovinyl ether, hydroxyalkyl allyl ethers such as 2-hydroxyethyl allyl ether, and hydroxyalkyl vinyl crotonates. Examples thereof include monomers having a hydroxyl group, such as hydroxyl group-containing vinyl carboxylate or allyl ester.

  The polyol (D) preferably has a number of active hydrogen groups (average number of functional groups) in one molecule of 1.9 to 4.0. When the number of active hydrogen groups is less than the lower limit, the physical properties of the coating film may be reduced. Moreover, when exceeding an upper limit, there exists a possibility that adhesiveness may fall.

  Moreover, it is preferable that the number average molecular weights of a polyol (D) exist in the range of 750-50000. If it is less than the lower limit, the adhesion may be lowered if it is less than the lower limit, and if it exceeds the upper limit, the solubility in a low-polar organic solvent or the adhesion may be lowered.

  Further, the blending ratio of the polyisocyanate composition of the two-component coating composition and the polyol (D) is not particularly limited, but the molar ratio of the isocyanate group in the isocyanate composition and the hydroxyl group in the polyol is not limited. It is preferable to blend so that the ratio is 0.5 to 1.5 in terms of R = isocyanate group / hydroxyl group. If it is less than the lower limit, the hydroxyl group becomes excessive, which may cause a decrease in adhesion. Moreover, there exists a possibility that a crosslinking density may fall and durability and the mechanical strength of a coating film may fall. When the upper limit is exceeded, the isocyanate group becomes excessive and reacts with moisture in the air, which may cause swelling of the coating film and a decrease in adhesion.

  The organic solvent (E) used as the diluting solvent is an organic solvent having an aniline point or a mixed aniline point in the range of 5 to 100 ° C., and may erode the undercoat layer when the paint is repeatedly applied. In order to obtain good recoatability, the aniline point or mixed aniline point is preferably in the range of 5 to 90 ° C, and the aniline point or mixed aniline point is preferably in the range of 5 to 85 ° C. Is more preferable. If it is less than the lower limit, the odor of the organic solvent becomes strong in addition to the decrease in recoatability, and the working environment may be deteriorated.

  Here, the “aniline point” is a minimum temperature at which an equal volume of aniline and a sample (organic solvent) exist as a uniform mixed solution. The aniline point or the mixed aniline point can be measured according to the test method described in “Petroleum products—aniline point and mixed aniline point test method” of JIS K 2256.

<Organic solvent (E)>
Specific examples of the organic solvent (E) include Solvesso 100 (manufactured by ExxonMobil, mixed aniline point: 14 ° C.), Solvesso 150 (manufactured by ExxonMobil, mixed aniline point: 18 ° C.), Swazol 100 (Maruzen Petrochemical Co., Ltd.) Manufactured, mixed aniline point: 25 ° C., Swazol 200 (manufactured by Maruzen Petrochemical Co., Ltd., mixed aniline point: 24 ° C.), swazol 1500 (manufactured by Maruzen Petrochemical Co., Ltd., mixed aniline point: 17 ° C.), swazol 1800 (Maruzen Petrochemical Co., Ltd.) Manufactured by Co., Ltd., mixed aniline point: 16 ° C.), Swazol 1000 (manufactured by Maruzen Petrochemical Co., Ltd., mixed aniline point: 13 ° C.), Vegasol ARO-80 (manufactured by ExxonMobil, mixed aniline point: 25 ° C.), Vegazole R-100 (ExxonMobil, mixed aniline point: 14 ° C.), Idemitsu Ivzole 150 (Idemitsu Kosan Co., Point: 15 ° C.), Idemitsu Ibsol 100 (produced by Idemitsu Kosan Co., Ltd., mixed aniline point: 14 ° C.), methylcyclohexane (aniline point: 40 ° C.), ethylcyclohexane (aniline point: 44 ° C.), mineral spirit (mineral terpene, In addition to aniline point (56 ° C), turpentine oil (aniline point: 20 ° C), HAWS (manufactured by Shell Japan, aniline point: 17 ° C), Essonaphtha No. 6 (manufactured by ExxonMobil, aniline point: 43 ° C), LAWS (manufactured by Shell Japan, aniline point: 44 ° C), pegasol 3040 (manufactured by ExxonMobil, aniline point: 55 ° C), A Solvent (JX Nippon Oil & Gas Energy Company, aniline point: 45 ° C), Clensol (manufactured by JX Nippon Mining & Energy Corporation, aniline point: 64 ° C), Mineral Spirit A (manufactured by JX Nippon Mining & Energy Corporation, aniline point: 43 ° C), Hyalom 2S ( JX Nippon Mining & Energy Corporation, aniline point: 44 ° C., LAWS (manufactured by Shell Chemicals Japan, aniline point: 44 ° C.), Pegasol 3040 (exxon mobile, aniline point: 55 ° C.), A solvent (JX Nikko) Nisseki Energy Co., Ltd., aniline point: 45 ° C), Clensol (manufactured by JX Nippon Mining & Energy Corporation, aniline : 64 ° C), Mineral Spirit A (manufactured by JX Nippon Mining & Energy Corporation, aniline point: 43 ° C), Hyalom 2S (manufactured by JX Nippon Mining & Energy Corporation, aniline point 4: 4 ° C), Linearlen 10 (manufactured by Idemitsu Kosan Co., Ltd.) , Α-olefinic hydrocarbon, aniline point: 44 ° C., linearene 12 (produced by Idemitsu Kosan Co., Ltd., α-olefinic hydrocarbon, aniline point: 54 ° C.), Exol D30 (manufactured by ExxonMobil, naphthenic solvent, aniline point: 63 ° C), Ricasolve 900 (manufactured by Nippon Nippon Chemical Co., Ltd., hydrogenated C9 solvent, aniline point: 53 ° C), Ricasolve 910B (manufactured by Nippon Nippon Chemical Co., Ltd., hydrogenated C9 solvent, aniline point: 40 ° C), Ricasolve 1000 (new) Nippon Rika Co., Ltd., hydrogenated C9 solvent, aniline point: 55 ° C.), IP solvent 1620 (manufactured by Idemitsu Kosan Co., Ltd., aniline point: 81 ° C.), IP sorbent 1016 (Idemitsu Kosan Co., Ltd., aniline point: 72 ° C.), IP Solvent 2028 (Idemitsu Kosan Co., Ltd., aniline point: 89 ° C.), IP Solvent 2835 (Idemitsu Kosan Co., Ltd., aniline point: 104 ° C.), Shellsol S ( Shell Chemicals Japan, aniline point: 78 ° C), Isopar G (ExxonMobil, aniline point: 78 ° C), Nisseki Isosol 300 (manufactured by JX Nippon Mining & Energy Corporation, aniline point: 80 ° C), normal paraffin SL (manufactured by JX Nippon Oil & Energy Corporation, aniline point: 80 ° C.), Marcazole R (manufactured by Maruzen Petrochemical Co., Ltd., aniline point: 88 ° C.) and the like. These organic solvents can be used alone or in admixture of two or more.

  These organic solvents contain aromatic hydrocarbon solvents, ester solvents, ether solvents, and can be used as solvents if the aniline point or mixed aniline point is within the range of 5 to 100 ° C. It is.

  Further, the blending ratio of the polyisocyanate composition in the two-component coating composition and the organic solvent (E) having an aniline point or mixed aniline point in the range of 5 to 100 ° C. is not particularly limited, In the present invention, the polyisocyanate composition / organic solvent (E) = 90/10 to 10/90 is preferable, and 80/20 to 20/80 is more preferable in terms of mass ratio.

  In addition, in the two-component coating composition, a known urethanization catalyst can be appropriately used in consideration of pot life, curing conditions, working conditions, and the like. Specifically, organic metal compounds such as dibutyltin diacetate, dibutyltin dilaurate and dioctyltin dilaurate, organic amines such as triethylenediamine and triethylamine, and salts thereof are selected and used. These catalysts can be used alone or in combination of two or more.

  In addition, the curing conditions of the two-pack type coating composition are not particularly limited because it varies depending on the catalyst or the like, but the curing temperature is −5 to 120 ° C. and the humidity is 10 to 95% RH. The curing time is 0.5 to 168 hours.

  In the two-component coating composition obtained by the present invention, for example, an antioxidant such as 2,6-di-tert-butyl-4-methylphenol, an ultraviolet absorber, a pigment, a dye, Additives such as a solvent, a flame retardant, a hydrolysis inhibitor, a lubricant, a plasticizer, a filler, an antistatic agent, a dispersant, a catalyst, a storage stabilizer, a surfactant, and a leveling agent can be appropriately blended.

Moreover, the two-component coating composition obtained by the present invention is applied onto the surface of an adherend by a known method such as spraying, brushing, dipping, or coater to form a coating film.
Here, the adherend is not particularly limited, and is stainless steel, phosphate-treated steel, zinc steel, iron, copper, aluminum, brass, glass, slate, acrylic resin, polycarbonate resin, polyethylene terephthalate resin, polyethylene naphthalate. Resin, polybutylene phthalate resin, polystyrene resin, AS resin, ABS resin, polycarbonate-ABS resin, 6-nylon resin, 6,6-nylon resin, MXD6 nylon resin, polyvinyl chloride resin, polyvinyl alcohol resin, polyurethane resin, phenol Resin, melamine resin, polyacetal resin, chlorinated polyolefin resin, polyolefin resin, polyamide resin, polyether ether ketone resin, polyphenylene sulfide resin, NBR resin, chloroprene resin, SBR resin, SE An adherend formed of a material such as S resin, an olefin resin such as polyethylene or polypropylene subjected to corona discharge treatment or other surface treatment, or a coating layer that can be intermediately formed on the surface of the adherend was formed. An adherend can be used.

  Since the film thickness of the coating film formed on the adherend surface layer is excellent in recoatability and durability, a film thickness of at least 10 μm may be formed on the adherend. When the film thickness is less than 10 μm, the durability is lowered, and there is a possibility that the coating film is torn by impact.

By using a specific oxidized carboxylate metal salt compound as an allophanate / isocyanurate catalyst in this way, even when organic diisocyanates with high hydrolyzable chlorine concentration are used as raw materials A polyisocyanate composition containing both bonding groups in one molecule can be obtained without inhibiting the reaction and the isocyanuration reaction.
Moreover, since the two-component coating composition using this polyisocyanate composition is excellent in solubility in a low-polar organic solvent, it suppresses corrosion of the adherend. In other words, when the two-component composition of the present invention is applied directly without removing the old coating film or applying a sealing agent during the repainting operation of the outer wall, etc., the problems such as the floating and swelling of the coating film are reduced. Can do. Furthermore, since the polyisocyanate composition of the present invention has a very low viscosity, when it is made into a two-component coating composition, high solid differentiation is possible, and organic solvents can be reduced.
As described above, the polyisocyanate composition and the two-component coating composition of the present invention are used in coatings for information equipment such as architectural coatings, heavy anticorrosion coatings, automotive coatings, home appliance coatings, personal computers and mobile phones. It can be used, and is particularly preferably used in architectural exterior paints and heavy anticorrosion paints for repainting applications.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

<Synthesis of Allophanate / Isocyanurate Catalyst (A)>
<Synthesis Example 1>
To a four-necked flask with a capacity of 300 ml equipped with a stirrer, a thermometer, a cooling pipe, and a gas introduction pipe, zinc (II) octylate (trade name: Nikka Octix zinc, divalent / tetravalent = 98/2, 100 g of Nippon Chemical Industry Co., Ltd. was charged, and the temperature was raised to 80 ° C. with stirring. After reaching 80 ° C., high purity oxygen gas was introduced at a flow rate of 20 ml / min and maintained at 80 ° C. for 36 hours to obtain an allophanate / isocyanurate-forming catalyst Cat-1.
The allophanate / isocyanurate catalyst Cat-1 was calculated by calculating the tetravalent zinc content from the total zinc content and the divalent zinc content by the iodine solution titration method. = 57/43. The appearance was a pale yellow liquid, the number of colors was 30 APHA, the viscosity at 25 ° C. was 300 mPa · s, and the turbidity was 0.

<Synthesis Example 2>
In a four-necked flask with a capacity of 300 ml equipped with a stirrer, a thermometer, a cooling pipe, and a gas introduction pipe, tin (II) octylate (trade name: Nikka Octix Tin, divalent / tetravalent = 97/3, 100 g of Nippon Chemical Industry Co., Ltd. was charged, and the temperature was raised to 80 ° C. with stirring. After reaching 80 ° C., high purity oxygen gas was introduced at a flow rate of 20 ml / min, and maintained at 80 ° C. for 36 hours to obtain an allophanate isocyanurate-forming catalyst Cat-2.
The allophanate / isocyanuration catalyst Cat-2 was obtained by calculating the tetravalent tin content from the total tin content and the divalent tin content by the iodine solution titration method. = 60/40. The appearance was a pale yellow liquid, the number of colors was 90 APHA, the viscosity at 25 ° C. was 390 mPa · s, and the turbidity was 0.

Table 1 shows the properties of the allophanate isocyanurate-forming catalysts Cat-1 to Cat- 2 .

<Synthesis of polyisocyanate composition>
<Example 1>
In a 2 liter four-necked flask equipped with a stirrer, a thermometer, a cooling tube, and a nitrogen gas introduction tube, hexamethylene diisocyanate HDI-1 (NCO content: 49.9% by mass, hydrolyzable chlorine content: 221.5ppm) and decane of tridecanol (manufactured by Kyowa Hakko Chemical Co., Ltd.) 120g, heated to 85 ° C with stirring under a nitrogen stream, and subjected to urethanization for 3 hours to obtain isocyanate group-terminated prepolymer I It was. Thereafter, 0.4 g of allophanate / isocyanurate catalyst Cat-1 was added to this isocyanate group-terminated prepolymer I, and the allophanate reaction and isocyanate were carried out at 110 ° C. until the molar ratio of allophanate groups / isocyanurate groups was 50/50. A nurating reaction was performed. Thereafter, 0.5 g of JP-508 (manufactured by Johoku Chemical Industry Co., Ltd., acidic phosphate ester) was added, a termination reaction was performed, and the reaction solution was cooled to room temperature to obtain isocyanate-terminated prepolymer II. The isocyanate-terminated prepolymer II was subjected to thin-film distillation at 130 ° C. × 0.04 kPa to remove unreacted HDI, thereby obtaining a purified polyisocyanate composition PI-1.
The polyisocyanate composition PI-1 had an NCO content of 16.2% by mass, a transparent appearance, a number average molecular weight of 860, a viscosity at 25 ° C. of 700 mPa · s, and a free HDI content of 0.2% by mass. It was. In addition, the allophanate group content in all linking groups was 49 mol%, the nurate group content was 51 mol%, and the urethane group content was 0 mol%.

<Method for measuring hydrolyzable chlorine>
The method for measuring hydrolyzable chlorine was determined by potentiometric titration with the following standard solution of silver nitrate according to JIS K1603-3 "Plastics-Polyurethane raw material aromatic isocyanate test method-Part 3: Determination of hydrolyzable chlorine". It is done.
(1) About 10 g of a sample is weighed in 500 ml of Erlenmeyer flask, and 50 ml of methanol is added and stirred. When crystals begin to precipitate on the side of the Erlenmeyer flask, add 200 ml of distilled water and boil for 30 minutes.
(2) After completion of boiling, cool to about 10 ° C. in an ice bath, add 10 drops of nitric acid, and perform potentiometric titration with a silver nitrate standard solution.
<Calculation of hydrolyzable chlorine content: H (%)>
Hydrolyzable chlorine is calculated in mass% as in the following formula, and then converted into units as appropriate.
H = 3.55 × V × c / m
(1) H: Hydrolyzable chlorine (mass%)
(2) V: amount of silver nitrate solution required for titration of sample (ml)
(3) c: concentration of silver nitrate solution (mol / l)
(4) m: Mass of the sample (g)
(5) 3.55: Coefficient (g / mol) combining chlorine atomic weight (35.5 g / mol), mg to g conversion coefficient (1000), and mass% conversion coefficient (100).

<NMR: measurement of allophanate group / nurate group / urethane group content>
(1) Measuring device: ECX400M (manufactured by JEOL Ltd., 1H-NMR)
(2) Measurement temperature: 23 ° C
(3) Sample concentration: 0.1 g / 1 ml
(4) Integration count: 16
(5) Relaxation time: 5 seconds (6) Solvent: Deuterium dimethyl sulfoxide (7) Chemical shift criteria: Hydrogen atom signal of methyl group in deuterium dimethyl sulfoxide (2.5 ppm)
(8) Evaluation method: signal of hydrogen atom bonded to nitrogen atom of allophanate group near 8.5 ppm, signal of hydrogen atom of methylene group adjacent to nitrogen atom of nurate group near 3.7 ppm, and around 7.0 ppm The content of the linking group was measured from the area ratio of the signal of the hydrogen atom bonded to the nitrogen atom of the urethane group.

<GPC: Measurement of molecular weight>
(1) Measuring instrument: HLC-8220 (manufactured by Tosoh Corporation)
(2) Column: TSKgel (manufactured by Tosoh Corporation)
・ G3000H-XL
・ G2500H-XL
・ G2000H-XL, G1000H-XL
(3) Carrier: THF (tetrahydrofuran)
(4) Detector: RI (refractive index) detector (5) Temperature: 40 ° C
(6) Flow rate: 1.000 ml / min
(7) Calibration curve: Standard polystyrene (manufactured by Tosoh Corporation)
F-80 (molecular weight: 7.06 × 10 ⁵ , molecular weight distribution: 1.05)
F-20 (molecular weight: 1.90 × 10 ⁵ , molecular weight distribution: 1.05)
F-10 (molecular weight: 9.64 × 10 ⁴ , molecular weight distribution: 1.01)
F-2 (molecular weight: 1.81 × 10 ⁴ , molecular weight distribution: 1.01)
F-1 (molecular weight: 1.02 × 10 ⁴ , molecular weight distribution: 1.02)
A-5000 (molecular weight: 5.97 × 10 ³ , molecular weight distribution: 1.02)
A-2500 (molecular weight: 2.63 × 10 ³ , molecular weight distribution: 1.05)
A-500 (molecular weight: 5.0 × 10 ² , molecular weight distribution: 1.14)
(8) Sample solution concentration: 0.5% THF solution

<Example 2>
A 2-liter four-necked flask equipped with a stirrer, thermometer, cooling pipe, and nitrogen gas introduction pipe was charged with 880 g of HDI-1 and 120 g of tridecanol and heated to 85 ° C. with stirring under a nitrogen stream. An isocyanate group-terminated prepolymer I was obtained by performing a urethanization reaction for 3 hours. Thereafter, 0.4 g of allophanate / isocyanurate catalyst Cat-2 was added to this isocyanate group-terminated prepolymer I, and the allophanate reaction and isocyanate were carried out at 110 ° C. until the molar ratio of allophanate groups / isocyanurate groups was 50/50. A nurating reaction was performed. Thereafter, 0.5 g of JP-508 was added to stop the reaction, and the reaction solution was cooled to room temperature to obtain an isocyanate-terminated prepolymer II. The isocyanate-terminated prepolymer II was subjected to thin-film distillation at 130 ° C. × 0.04 kPa to remove unreacted HDI, thereby obtaining a purified polyisocyanate composition PI-2.
The polyisocyanate composition PI-2 had an NCO content of 16.4% by mass, an appearance of a transparent liquid, a number average molecular weight of 850, a viscosity at 25 ° C. of 720 mPa · s, and a free HDI content of 0.2% by mass. It was. In addition, the allophanate group content in all linking groups was 50 mol%, the nurate group content was 50 mol%, and the urethane group content was 0 mol%.

<Example 4>
A 2-liter four-necked flask equipped with a stirrer, thermometer, cooling pipe, and nitrogen gas introduction pipe was charged with 950 g of HDI-1 and 50 g of 2-propanol (referred to as IPA) and stirred under a nitrogen stream. The isocyanate group-terminated prepolymer I was obtained by heating to 85 [deg.] C. and carrying out a urethanization reaction for 3 hours. Thereafter, 0.4 g of the allophanate isocyanurate catalyst Cat-2 was added to the isocyanate group-terminated prepolymer I, and the allophanate reaction and isocyanate were performed at 110 ° C. until the molar ratio of allophanate groups / isocyanurate groups was 75/25. A nurating reaction was performed. Thereafter, 0.5 g of JP-508 was added to stop the reaction, and the reaction solution was cooled to room temperature to obtain an isocyanate-terminated prepolymer II. The isocyanate-terminated prepolymer II was subjected to thin-film distillation at 130 ° C. × 0.04 kPa to remove unreacted HDI, thereby obtaining a purified polyisocyanate composition PI-4.
Polyisocyanate composition PI-4 had an NCO content of 19.3% by mass, an external appearance that was a transparent liquid, a number average molecular weight of 580, a viscosity at 25 ° C. of 370 mPa · s, and a free HDI content of 0.1% by mass. It was. Further, the allophanate group content in all the linking groups was 75 mol%, the nurate group content was 24 mol%, and the urethane group content was 1 mol%.

<Example 5>
A 2-liter four-necked flask equipped with a stirrer, thermometer, cooling pipe, and nitrogen gas introduction pipe was charged with 910 g of HDI-1 and 90 g of 2-ethylhexanol, and stirred at 85 ° C. under a nitrogen stream. And an urethanization reaction was carried out for 3 hours to obtain an isocyanate group-terminated prepolymer I. Thereafter, 0.4 g of allophanate / isocyanurate catalyst Cat-2 was added to this isocyanate group-terminated prepolymer I, and allophanate reaction and A nurating reaction was performed. Thereafter, 0.5 g of JP-508 was added to stop the reaction, and the reaction solution was cooled to room temperature to obtain an isocyanate-terminated prepolymer II. This isocyanate-terminated prepolymer II was subjected to thin-film distillation at 130 ° C. × 0.04 kPa to remove unreacted HDI, thereby obtaining a purified polyisocyanate composition PI-5.
The polyisocyanate composition PI-5 had an NCO content of 17.4% by mass, an appearance that was a transparent liquid, a number average molecular weight of 670, a viscosity at 25 ° C. of 380 mPa · s, and a free HDI content of 0.1% by mass. It was. In addition, the allophanate group content in all linking groups was 78 mol%, the nurate group content was 22 mol%, and the urethane group content was 0 mol%.

<Example 6>
A 2-liter four-necked flask equipped with a stirrer, thermometer, cooling pipe, and nitrogen gas introduction pipe was charged with 880 g of HDI-1 and 120 g of tridecanol and heated to 85 ° C. with stirring under a nitrogen stream. An isocyanate group-terminated prepolymer I was obtained by performing a urethanization reaction for 3 hours. Thereafter, 0.4 g of the allophanate isocyanurate catalyst Cat-2 was added to the isocyanate group-terminated prepolymer I, and the allophanate reaction and isocyanate were performed at 110 ° C. until the molar ratio of allophanate groups / isocyanurate groups was 75/25. A nurating reaction was performed. Thereafter, 0.5 g of JP-508 was added to stop the reaction, and the reaction solution was cooled to room temperature to obtain an isocyanate-terminated prepolymer II. The isocyanate-terminated prepolymer II was subjected to thin-film distillation at 130 ° C. × 0.04 kPa to remove unreacted HDI, thereby obtaining a purified polyisocyanate composition PI-6.
The polyisocyanate composition PI-6 had an NCO content of 15.8% by mass, a transparent appearance, a number average molecular weight of 740, a viscosity at 25 ° C. of 420 mPa · s, and a free HDI content of 0.1% by mass. It was. Further, the allophanate group content in all the linking groups was 76 mol%, the nurate group content was 24 mol%, and the urethane group content was 0 mol%.

<Example 7>
850 g of HDI-1 and 2-octyldodecanol (trade name: Calcoal 200GD, manufactured by Kao Corporation) in a 2 liter four-necked flask equipped with a stirrer, thermometer, cooling pipe, and nitrogen gas introduction pipe An isocyanate group-terminated prepolymer I was obtained by charging 150 g, heating to 85 ° C. with stirring under a nitrogen stream, and performing a urethanization reaction for 3 hours. Thereafter, 0.4 g of the allophanate isocyanurate catalyst Cat-2 was added to the isocyanate group-terminated prepolymer I, and the allophanate reaction and isocyanate were performed at 110 ° C. until the molar ratio of allophanate groups / isocyanurate groups was 75/25. A nurating reaction was performed. Thereafter, 0.5 g of JP-508 was added to stop the reaction, and the reaction solution was cooled to room temperature to obtain an isocyanate-terminated prepolymer II. The isocyanate-terminated prepolymer II was subjected to thin-film distillation at 130 ° C. × 0.04 kPa to remove unreacted HDI, thereby obtaining a purified polyisocyanate composition PI-7.
Polyisocyanate composition PI-7 had an NCO content of 15.2% by mass, an appearance that was a transparent liquid, a number average molecular weight of 960, a viscosity at 25 ° C. of 460 mPa · s, and a free HDI content of 0.2% by mass. It was. Further, the allophanate group content in all the linking groups was 76 mol%, the nurate group content was 24 mol%, and the urethane group content was 0 mol%.

<Example 8>
A 2-liter four-necked flask equipped with a stirrer, thermometer, cooling pipe, and nitrogen gas introduction pipe was charged with 880 g of HDI-1 and 120 g of tridecanol and heated to 85 ° C. with stirring under a nitrogen stream. An isocyanate group-terminated prepolymer I was obtained by performing a urethanization reaction for 3 hours. Thereafter, 0.4 g of the allophanate / isocyanurate catalyst Cat-2 was added to the isocyanate group-terminated prepolymer I, and the allophanate reaction and isocyanate were performed at 110 ° C. until the molar ratio of allophanate group / isocyanurate group was 85/15. A nurating reaction was performed. Thereafter, 0.5 g of JP-508 was added to stop the reaction, and the reaction solution was cooled to room temperature to obtain an isocyanate-terminated prepolymer II. This isocyanate-terminated prepolymer II was subjected to thin-film distillation at 130 ° C. × 0.04 kPa to remove unreacted HDI, thereby obtaining a purified polyisocyanate composition PI-8.
The polyisocyanate composition PI-8 had an NCO content of 15.2% by mass, a transparent appearance, a number average molecular weight of 700, a viscosity at 25 ° C. of 330 mPa · s, and a free HDI content of 0.1% by mass. It was. In addition, the allophanate group content in all linking groups was 82 mol%, the nurate group content was 18 mol%, and the urethane group content was 0 mol%.

<Example 9>
A 2-liter four-necked flask equipped with a stirrer, thermometer, cooling tube, and nitrogen gas introduction tube was charged with 980 g of HDI-1 and 20 g of tridecanol, and heated to 85 ° C. with stirring under a nitrogen stream. An isocyanate group-terminated prepolymer I was obtained by performing a urethanization reaction for 3 hours. Thereafter, 0.4 g of allophanate / isocyanurate catalyst Cat-2 was added to this isocyanate group-terminated prepolymer I, and the allophanate reaction and isocyanate were performed at 110 ° C. until the molar ratio of allophanate group / isocyanurate group was 30/70. A nurating reaction was performed. Thereafter, 0.5 g of JP-508 was added to stop the reaction, and the reaction solution was cooled to room temperature to obtain an isocyanate-terminated prepolymer II. This isocyanate-terminated prepolymer II was subjected to thin-film distillation at 130 ° C. × 0.04 kPa to remove unreacted HDI, thereby obtaining a purified polyisocyanate composition PI-9.
The polyisocyanate composition PI-9 had an NCO content of 21.0% by mass, a transparent appearance, a number average molecular weight of 600, a viscosity at 25 ° C. of 360 mPa · s, and a free HDI content of 0.1% by mass. It was. In addition, the allophanate group content in all linking groups was 35 mol%, the nurate group content was 65 mol%, and the urethane group content was 0 mol%.

<Example 10>
A 2-liter four-necked flask equipped with a stirrer, thermometer, cooling tube, and nitrogen gas introduction tube was charged with 980 g of HDI-1 and 20 g of tridecanol, and heated to 85 ° C. with stirring under a nitrogen stream. An isocyanate group-terminated prepolymer I was obtained by performing a urethanization reaction for 3 hours. Thereafter, 0.4 g of allophanate / isocyanurate catalyst Cat-2 was added to this isocyanate group-terminated prepolymer I and allophanate reaction and A nurating reaction was performed. Thereafter, 0.5 g of JP-508 was added to stop the reaction, and the reaction solution was cooled to room temperature to obtain an isocyanate-terminated prepolymer II. This isocyanate-terminated prepolymer II was thin-film distilled at 130 ° C. × 0.04 kPa to remove unreacted HDI, thereby obtaining a purified polyisocyanate composition PI-10.
The polyisocyanate composition PI-10 had an NCO content of 21.4% by mass, an appearance of a transparent liquid, a number average molecular weight of 620, a viscosity at 25 ° C. of 400 mPa · s, and a free HDI content of 0.2% by mass. It was. In addition, the allophanate group content in all linking groups was 23 mol%, the nurate group content was 77 mol%, and the urethane group content was 0 mol%.

<Comparative Example 1>
A 2-liter four-necked flask equipped with a stirrer, thermometer, cooling pipe, and nitrogen gas introduction pipe was charged with 880 g of HDI-1 and 120 g of tridecanol and heated to 85 ° C. with stirring under a nitrogen stream. An isocyanate group-terminated prepolymer I was obtained by performing a urethanization reaction for 3 hours. Thereafter, 0.4 g of zinc octylate (II) (trade name: Nikka Octix zinc, divalent / tetravalent = 98/2, manufactured by Nippon Kagaku Sangyo Co., Ltd.) was added to the isocyanate group-terminated prepolymer I at 110 ° C. The allophanate reaction and isocyanurate reaction were carried out until the allophanate group / isocyanurate group molar ratio reached 50/50. Thereafter, the reaction did not proceed before the molar ratio of allophanate group / isocyanurate group reached 50/50. Therefore, 0.5 g of JP-508 was added, and the reaction solution was cooled to room temperature to obtain isocyanate-terminated prepolymer II. Obtained. This isocyanate-terminated prepolymer II was subjected to thin-film distillation at 130 ° C. × 0.04 kPa to remove unreacted HDI, thereby obtaining a purified polyisocyanate composition PI-11.
The polyisocyanate composition PI-11 has an NCO content of 14.5% by mass, an appearance of a transparent liquid, a number average molecular weight of 620, a viscosity at 25 ° C. of 230 mPa · s, and a free HDI content of 0.2% by mass. It was. In addition, the allophanate group content in all linking groups was 92 mol%, the nurate group content was 7 mol%, and the urethane group content was 1 mol%.

<Comparative example 2>
A 2-liter four-necked flask equipped with a stirrer, thermometer, cooling pipe, and nitrogen gas introduction pipe was charged with 880 g of HDI-1 and 120 g of tridecanol and heated to 85 ° C. with stirring under a nitrogen stream. An isocyanate group-terminated prepolymer I was obtained by performing a urethanization reaction for 3 hours. Thereafter, 0.4 g of tin (II) octylate (trade name: Nikka Octix tin, divalent / tetravalent = 97/3, manufactured by Nippon Kagaku Sangyo Co., Ltd.) was added to the isocyanate group-terminated prepolymer I at 110 ° C. The allophanate reaction and isocyanurate reaction were carried out until the allophanate group / isocyanurate group molar ratio reached 50/50. Thereafter, the reaction did not proceed before the molar ratio of allophanate group / isocyanurate group reached 50/50. Therefore, 0.5 g of JP-508 was added, and the reaction solution was cooled to room temperature to obtain isocyanate-terminated prepolymer II. Obtained. This isocyanate-terminated prepolymer II was subjected to thin-film distillation at 130 ° C. × 0.04 kPa to remove unreacted HDI, thereby obtaining a purified polyisocyanate composition PI-12.
The polyisocyanate composition PI-12 had an NCO content of 14.8% by mass, a transparent appearance, a number average molecular weight of 620, a viscosity at 25 ° C. of 290 mPa · s, and a free HDI content of 0.2% by mass. It was. In addition, the allophanate group content in all linking groups was 87 mol%, the nurate group content was 12 mol%, and the urethane group content was 1 mol%.

<Comparative Example 3>
A 2-liter four-necked flask equipped with a stirrer, thermometer, cooling pipe, and nitrogen gas introduction pipe was charged with 880 g of HDI-1 and 120 g of tridecanol and heated to 85 ° C. with stirring under a nitrogen stream. An isocyanate group-terminated prepolymer I was obtained by performing a urethanization reaction for 3 hours. Thereafter, this isocyanate group-terminated prepolymer I and zirconium octylate (II) adjusted to 50% by mass with mineral spirit A (trade name: Nikka Octix Zirconium, divalent / tetravalent = 99/1, Nippon Chemical Industry Co., Ltd.) 0.8 g of a solution (manufactured by Kogyo Co., Ltd.) was added, and an allophanate reaction and isocyanurate reaction were carried out at 110 ° C. until the allophanate group / isocyanurate group molar ratio reached 50/50. Thereafter, the reaction did not proceed before the molar ratio of allophanate group / isocyanurate group reached 50/50. Therefore, 0.5 g of JP-508 was added, and the reaction solution was cooled to room temperature to obtain isocyanate-terminated prepolymer II. Obtained. This isocyanate-terminated prepolymer II was subjected to thin-film distillation at 130 ° C. × 0.04 kPa to remove unreacted HDI, thereby obtaining a purified polyisocyanate composition PI-13.
Polyisocyanate composition PI-13 had an NCO content of 14.4% by mass, an appearance that was a transparent liquid, a number average molecular weight of 600, a viscosity at 25 ° C. of 150 mPa · s, and a free HDI content of 0.2% by mass. It was. Further, the allophanate group content in all the linking groups was 95 mol%, the nurate group content was 3 mol%, and the urethane group content was 1 mol%.

<Comparative example 4>
A 2-liter four-necked flask equipped with a stirrer, thermometer, cooling pipe, and nitrogen gas introduction pipe was charged with 880 g of HDI-1 and 120 g of tridecanol and heated to 85 ° C. with stirring under a nitrogen stream. An isocyanate group-terminated prepolymer I was obtained by performing a urethanization reaction for 3 hours. Thereafter, 0.2 g of tin (II) octylate (divalent / tetravalent = 97/3) was added to the isocyanate group-terminated prepolymer I, and an allophanatization reaction was performed at 110 ° C. Thereafter, the mixture is cooled to 60 ° C., 0.2 g of 2-hydroxypropyltrimethylammonium octylate (trade name: DABCO TMR, manufactured by Air Products Japan), which is an isocyanurate-forming catalyst, is added, and isocyanuration reaction is performed at 60 ° C. Went. Then, 0.25g of JP-508 was added, the termination reaction was performed, the reaction liquid was cooled to room temperature, and the isocyanate terminal prepolymer II was obtained. This isocyanate-terminated prepolymer II was subjected to thin-film distillation at 130 ° C. × 0.04 kPa to remove unreacted HDI, thereby obtaining a purified polyisocyanate composition PI-14.
The polyisocyanate composition PI-14 had an NCO content of 16.5% by mass, an appearance that was a transparent liquid, a number average molecular weight of 860, a viscosity at 25 ° C. of 720 mPa · s, and a free HDI content of 0.2% by mass. It was. In addition, the allophanate group content in all linking groups was 47 mol%, the nurate group content was 52 mol%, and the urethane group content was 1 mol%.

  Tables 2 to 5 show the blending amounts and properties of the raw materials used for the polyisocyanate composition PI-1 to polyisocyanate composition PI-14.

Abbreviations of the raw materials used in Table 2 are as follows.
(1) HDI-1: Hexamethylene diisocyanate (hydrolyzable chlorine content: 221.5 ppm)
(2) Zirconium octylate solution: 50% by weight solid solution of mineral spirit A (3) DABCO TMR: 2-hydroxypropyltrimethylammonium octylate (4) JP-508: acidic phosphate

As shown in Table 3 above, the polyisocyanate compositions according to Examples 1 and 2 are not affected by hydrolyzable chlorine, and the allophanate reaction and the isocyanurate reaction proceed efficiently, and the allophanate group And a polyisocyanate composition in which both bonding groups of isocyanurate groups are present in one molecule. This modified polyisocyanate is excellent in storage stability and tolerance.
In contrast, in the polyisocyanate compositions according to Comparative Examples 1 to 3, the isocyanurate reaction hardly proceeded under the influence of hydrolyzable chlorine. In addition, the polyisocyanate composition of Comparative Example 4 had an isocyanurate-forming reaction, and it was possible to achieve the target composition ratio. However, the allophanate group-containing polyisocyanate-modified product and the isocyanurate group-containing polyisocyanate-modified product The mixture was inferior in storage stability and tolerance.

The abbreviations of the raw materials used in Table 4 are as follows.
(1) HDI-1: Hexamethylene diisocyanate (hydrolyzable chlorine content: 221.5 ppm)
(2) IPA: 2-propanol (3) Calcoal 200GD: 2-octyldodecanol (4) JP-508: acidic phosphate ester

  As shown in Table 5 above, the polyisocyanate compositions according to Examples 4 to 10 were excellent in storage stability regardless of the type of alkyl chain of the monoalcohol. Moreover, since the arbitrary allophanate group / isocyanurate group molar ratio was not subject to reaction inhibition, it was easy to adjust.

<Adjustment of two-component coating composition>
As shown in Tables 6, 8 and 10, the blending amount is such that the polyol (D) and the resulting polyisocyanate composition are R (molar ratio of isocyanate group / hydroxyl group) = 1. In addition, titanium pigment (trade name: CR-90, crystal structure: rutile type, manufactured by Ishihara Sangyo Co., Ltd.) and organic solvent (E) as a pigment are blended to a solid content of 50%, and a homomixer is used. The mixture was stirred at 300 rpm for 3 minutes to prepare a two-component coating composition. Here, the polyol (D) includes acrylic polyol (trade name: Acridic HU-596, hydroxyl value: 30 mgKOH / g, manufactured by DIC), polyester polyol (trade name: N-131, hydroxyl value: 150 mgKOH / g). , Nippon Polyurethane Industry Co., Ltd.) and fluorine-based polyol (trade name: Lumiflon LF800, hydroxyl value: 22 mgKOH / g, manufactured by Asahi Glass Co., Ltd.) Energy Co., Ltd.), HAWS (manufactured by Shell Chemicals), and ethyl acetate (manufactured by Showa Denko) were used for adjustment.

<Coating method and test piece adjustment>
Using the applicator on a steel plate (JIS G3141, trade name: SPCC-SB, presence / absence of treatment: PF-1077, manufactured by Nippon Test Panel Industry Co., Ltd.) obtained by degreasing the adjusted two-component paint composition with methyl ethyl ketone, respectively, It applied so that it might become. Thereafter, heat treatment was carried out in a dryer at a temperature of 60 ° C. for 1 hour, followed by curing for 7 days in an environment at a temperature of 23 ° C. and a relative humidity of 50% to obtain a coating film.

The abbreviations of the raw materials used in Table 6 are as follows.
(1) Acrydic HU-596: acrylic polyol (hydroxyl value: 30 mg KOH / g)
(2) CR-90: Titanium oxide

As shown in Table 7 above, the two-component coating compositions according to Examples 11 to 12 had sufficiently high pencil hardness, excellent weather resistance, and other physical properties.
On the other hand, the two-component coating compositions according to Comparative Examples 5 to 7 were inferior in pencil hardness and weather resistance. Further, the two-component coating composition of Comparative Example 8 was slightly inferior in weather resistance.

Abbreviations of raw materials used in Table 8 are as follows.
(1) Acrydic HU-596: acrylic polyol (hydroxyl value: 30 mg KOH / g)
(2) CR-90: Titanium oxide

  As shown in Table 9 above, the two-component coating compositions according to Examples 14 to 20 had sufficiently high pencil hardness, excellent weather resistance, and other physical properties.

Abbreviations of the raw materials used in Table 10 are as follows.
(1) Acrydic HU-596: acrylic polyol (hydroxyl value: 30 mg KOH / g)
(2) Nippon Runan 131: Polyester polyol (Hydroxyl value: 150 mgKOH / g)
(3) Lumiflon LF800: fluorine-based polyol (hydroxyl value: 22 mgKOH / g)

As shown in Table 11 above, the two-component coating compositions according to Examples 21 to 25 were excellent in various physical properties such as weather resistance without depending on the film thickness.
On the other hand, the two-component coating composition of Comparative Example 9 in which the organic solvent was changed to ethyl acetate was inferior in recoatability.

(1) Evaluation test 1:
<Storage stability>
The obtained polyisocyanate composition was allowed to stand at −10 ° C. and 25 ° C. for 168 hours, and the presence or absence of turbidity, suspended matter and precipitate was visually evaluated.

<Evaluation criteria>
・ No turbidity, suspended matter, or precipitate is observed: Pass (Evaluation: ○)
・ Muddyness is recognized: Pass (Evaluation: △)
-Precipitates are observed: reject (evaluation: x)

(2) Evaluation test 2:
<Tolerance>
1 g each of the obtained polyisocyanate composition was sampled, and HAWS (shell chemicals), mineral spirit A (manufactured by JX Nippon Mining & Energy Corporation), and IP solvent 2028 (manufactured by Idemitsu Kosan Co., Ltd.) having different aniline points were added to each. Then, the titer that caused turbidity was calculated as the end point.

<Calculation formula>
T = L / S
・ T: Tolerance (times)
L: titration amount of organic solvent (g)
S: Sample amount (g)

(3) Evaluation test 3:
<Glossiness>
The glossiness at 60 ° was measured with a haze-gloss reflectometer for the coating films obtained in Examples 25 to 44 and Comparative Examples 7 to 11 according to JIS Z8741.

<Evaluation criteria>
・ 80% or more: Pass (Evaluation: ○)
-60% or more and less than 80: Pass (Evaluation: Δ)
-Less than 60%: Fail (Evaluation: x)

(4) Evaluation test 4:
<Pencil hardness>
In accordance with JIS K5600-5-4: 1999, the hardness of a pencil that could not be torn was measured.

(5) Evaluation test 5:
<Flexibility>
Using a cylindrical mandrel with a diameter of 2 mm according to JIS K5600-5-1: 1999 flex resistance test, evaluating the presence or absence of film cracking and peeling from the steel sheet when bent by the cylindrical mandrel did.

<Evaluation criteria>
・ No cracking or peeling of coating film: Pass (Evaluation: ○)
-Cracking and peeling of the coating film have occurred: Fail (Evaluation: x)

(6) Evaluation test 6:
<Copping resistance>
According to the cupping resistance test of JIS K5600-5-2: 1999, the indentation depth (mm) until peeling from the steel sheet was measured after cracking of the coating film when subjected to partial deformation by indentation.

(7) Evaluation test 7:
<Weight drop resistance>
According to JIS K5600-5-3: 1999 bending resistance test, use a weight of 10.3 mm in diameter and 0.5 kg in mass, and set the minimum drop height (cm) at which the coating film will crack and peel off. It was measured.

(8) Evaluation test 8:
<Adhesion>
According to a cross cut tape peeling test of JIS K5600-5-6: 1999, a 1 mm square cross cut (10 × 10) was cut in the coating film, and a tape peel test was performed to measure the number of remaining sheets.

(9) Evaluation test 9:
<Weather resistance>
The coating films obtained in Examples 25 to 44 and Comparative Examples 7 to 11 were subjected to an accelerated weather resistance test under the following conditions.
・ Test equipment: QUV (manufactured by Q-LAB)
・ Lamp: EL-313
Illuminance: 0.59 w / m ²
・ Λmax: 313 nm
1 cycle: 12 hours [UV irradiation: 8 hours (temperature 70 ° C.), condensation: 4 hours (temperature 50 ° C.)]
・ Test time: 964 hours

<Evaluation criteria>
According to JIS Z8741, the glossiness at 60 ° was measured with a haze-gloss reflectometer, and the gloss retention was calculated. The gloss retention was determined by the following formula.
Gloss retention (%) = 100 × Glossiness after weathering test ÷ Initial glossiness / 80% or more: Pass (Evaluation: ○)
・ 70% to less than 80%: Pass (Evaluation: △)
-Less than 70%: Fail (Evaluation: x)

(10) Evaluation test 10:
<Recoatability>
An adherend was prepared by forming 50 μm of the two-component coating composition (Acridic HU-596 / polyisocyanate composition PI-2) of Example 12 on a steel plate. The adjusted two-component coating composition was applied to the upper layer of the adherend so as to have a film thickness of 50 μm, and the swelling of the coating film and the presence or absence of wrinkles were visually confirmed.

<Evaluation criteria>
・ No change in appearance of coating film: Pass (Evaluation: ○)
・ Swelling and wrinkle of the coating film are generated: reject (evaluation: x)

Claims (7)

A polyisocyanate composition obtained from an allophanate isocyanurate catalyst (A) represented by the general formula (1), an organic diisocyanate (B), and a monoalcohol (C), the allophanate isocyanurate catalyst The polyisocyanate composition, wherein the tetravalent metal content of (A) is calculated based on an iodine solution titration method and is at least 10% by mass with respect to the total metal content.

(M in the general formula (1) represents a tetravalent metal selected from tin and zinc. R represents a bonding group selected from an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group, and a phenyl group. )   2. The polyisocyanate composition according to claim 1, wherein the polyisocyanate composition contains allophanate groups / isocyanurate groups in a molar ratio of allophanate groups / isocyanurate groups = 80/20 to 30/70.   The organic diisocyanate (B) is an aliphatic or alicyclic diisocyanate, and the carbon number of the alkyl group of the monoalcohol (C) is 3 to 20, wherein the organic diisocyanate (B) has 3 to 20 carbon atoms. Polyisocyanate composition.   A two-component coating composition comprising the polyisocyanate composition according to any one of claims 1 to 3 and a polyol (D).   The polyisocyanate composition according to any one of claims 1 to 3, the polyol (D), and an organic solvent (E) having an aniline point according to JIS K 2256 or a mixed aniline point of 5 to 100 ° C. A two-component coating composition comprising:   A polyisocyanate composition obtained from a reaction between an organic diisocyanate (B) and a monoalcohol (C) in the presence of an allophanate isocyanurate-forming catalyst (A) represented by the general formula (1) according to claim 1. The tetravalent metal content of the allophanate isocyanurate catalyst (A) is calculated based on the iodine solution titration method and is at least 10% by mass with respect to the total metal content. A method for producing a polyisocyanate composition.   An allophanate group is produced by reacting an organic diisocyanate (B) with a monoalcohol (C) in the presence of the allophanate isocyanurate-forming catalyst (A) represented by the general formula (1) according to claim 1. And a production method of a polyisocyanate composition comprising a linking group that immediately generated an isocyanurate group.