JP2017218562A - Polyisocyanate composition, coating composition, coat, and article containing coat - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyisocyanate composition that has excellent moisture stability while maintaining curability, and can form a coat having excellent adhesion and weather resistance.SOLUTION: A polyisocyanate composition contains polyisocyanate that is obtained from (1) at least one diisocyanate selected from the group consisting of aliphatic diisocyanate and alicyclic diisocyanate and (2) divalent or more and tetravalent or less polycaprolactone polyol and contains an isocyanurate bond. In the composition, a caprolactone dimer content is 50 ppm or more and 500 ppm or less.SELECTED DRAWING: None

Description

  The present invention relates to a polyisocyanate composition, a coating composition, a coating film, and an article comprising the coating film.

  Polyurethane coatings using a polyisocyanate composition as a curing agent are capable of forming a coating film excellent in abrasion resistance, chemical resistance, weather resistance, and stain resistance, and therefore, the demand thereof is increasing year by year. Since the isocyanate group of the polyisocyanate composition as a curing agent reacts with the hydroxyl group of a polyol frequently used as a main agent at room temperature, the paint containing them is applied to various adherends and has a wide range of applications. In recent years, such paints have been eagerly desired to shorten the time required to form a coating film and to improve curability at low temperatures from the viewpoint of energy saving and productivity improvement. In order to satisfy these demands, for example, Patent Document 1 proposes a polyisocyanate composition having a high number of isocyanate average functional groups.

JP-A-6-312969

However, since a can for storing a polyisocyanate composition is opened and closed many times each time it is used, there is a problem that isocyanate groups react with moisture in the air. Moreover, the polyisocyanate composition described in Patent Document 1 has room for further improvement with respect to the adhesion and weather resistance of the resulting coating film.
Therefore, the present invention provides a polyisocyanate composition capable of forming a coating film having excellent moisture stability and excellent adhesion and weather resistance while maintaining curability. Objective.

  As a result of repeated studies to solve the above-described problems of the prior art, the inventor obtained from one or more diisocyanates selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates and polycaprolactone polyols, and isocyanurate-bonded The polyisocyanate composition containing a polyisocyanate having the following is excellent in moisture stability while maintaining curability, and in such a polyisocyanate composition, when the caprolactone dimer content is adjusted to a predetermined range, It has been found that it becomes a curing agent capable of forming a polyurethane coating film having excellent adhesion and weather resistance, and has led to the present invention.

That is, the present invention is as follows.
[1] It is obtained from (1) at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates, and (2) a polycaprolactone polyol having a valence of 2 to 4 and having an isocyanurate bond. Containing polyisocyanate,
The caprolactone dimer content is 50 ppm or more and 500 ppm or less,
Polyisocyanate composition.
[2] The polyisocyanate composition according to [1], wherein the trimer concentration is 2% by mass or more and 40% by mass or less.
[3] The polyisocyanate composition according to [1] or [2], wherein the (2) polycaprolactone polyol is trivalent and has a number average molecular weight of 250 or more and 2000 or less.
[4] The NCO content is 10% by mass or more and 24% by mass or less and the viscosity at 25 ° C. is 5000 mPa.s when measured in a state not containing diisocyanate and solvent. s to 1,000,000 mPa.s s or less,
The polyisocyanate composition according to any one of [1] to [3], wherein the average number of isocyanate groups of the polyisocyanate is 4.5 or more and 10 or less.
[5] A two-component coating composition containing the polyisocyanate composition according to any one of [1] to [4] and a polyvalent active hydrogen compound.
[6] The polyisocyanate composition according to any one of [1] to [4], wherein at least a part of the isocyanate groups of the polyisocyanate is blocked with a blocking agent.
[7] A one-pack type coating composition containing the polyisocyanate composition according to [6] and a polyvalent active hydrogen compound.
[8] A method for forming a coating film comprising a step of applying the two-component coating composition according to [5] or the one-component coating composition according to [7].
[9] A method for producing an article provided with a coating film, comprising a step of applying the two-component coating composition according to [5] or the one-component coating composition according to [7].

  ADVANTAGE OF THE INVENTION According to this invention, the polyisocyanate composition which can obtain the coating film which has high moisture stability, and is excellent in adhesiveness and a weather resistance, maintaining sclerosis | hardenability can be provided.

  Hereinafter, a mode for carrying out the present invention (hereinafter simply referred to as “the present embodiment”) will be described in detail. The present invention is not limited to the following embodiments, and various modifications can be made within the scope of the invention.

[Polyisocyanate composition]
The polyisocyanate contained in the polyisocyanate composition of the present embodiment is a compound obtained from diisocyanate and polycaprolactone polyol, and has an isocyanurate bond in its structure.
In the present embodiment, examples of the polyisocyanate include multimers (oligomers) of about 2 to 20 dimers of diisocyanate (multimers formed from two or more diisocyanate molecules).

The polyisocyanate composition of the present embodiment has a caprolactone dimer content of 50 ppm or more and 500 ppm or less, preferably 80 ppm or more and 400 ppm or less, more preferably 100 ppm or more and 250 ppm.
The coating film which is excellent in adhesiveness can be formed because it is 50 ppm or more. The coating film which is excellent in a weather resistance can be formed because it is 500 ppm or less.
In the present embodiment, the caprolactone dimer content in the polyisocyanate composition can be controlled, for example, by adjusting the caprolactone dimer content in caprolactone used when producing a polycaprolactone polyol that is a raw material of polyisocyanate. it can.

  In the polyisocyanate composition of the present embodiment, the concentration of the polyisocyanate which is a diisocyanate trimer is preferably 2% by mass or more and 40% by mass or less, more preferably 5% by mass or more and 35% by mass or less. More preferably, it is 10 mass% or more and 30 mass% or less, More preferably, it is 13 mass% or more and 25 mass% or less. By being 2 mass% or more, the moisture stability of the polyisocyanate composition tends to be more excellent. By being 40% by mass or less, curability tends to be more excellent. The trimer concentration can be measured by GPC. Specifically, it can be measured by the method described in Examples described later.

The NCO content when measured without the diisocyanate and solvent in the polyisocyanate composition is preferably 10% by mass or more and 24% by mass or less, and more preferably 12% by mass or more and 22% by mass or less. When the NCO content is in such a range, the curability tends to be sufficient. The NCO content can be measured by the method described in Examples described later.
The viscosity at 25 ° C. when measured without the diisocyanate and solvent of the polyisocyanate composition is preferably 5000 mPa.s. s to 1,000,000 mPa.s s or less, more preferably 10,000 mPa.s. s to 800,000 mPa.s s or less. When the viscosity is in such a range, the polyisocyanate composition tends to be easily handled and the curability tends to be sufficient. A viscosity can be measured by the method as described in the Example mentioned later.

  The number average molecular weight of the polyisocyanate contained in the polyisocyanate composition is preferably 500 or more and 5000 or less, more preferably 800 or more and 4000 or less. When the number average molecular weight is in such a range, the curability tends to be sufficient. The number average molecular weight can be measured by the method described in Examples described later.

  The average number of isocyanate groups in the polyisocyanate contained in the polyisocyanate composition (average value of the number of isocyanate groups contained in one molecule of polyisocyanate) is preferably 4.5 or more and 10 or less, more preferably 5.0 or more. 9.0 or less. When the average number of isocyanate groups is in such a range, curability tends to be sufficient. The average number of isocyanate groups can be measured by the method described in Examples described later.

  The residual diisocyanate concentration of the polyisocyanate composition is preferably 0.01% by mass or more and 1% by mass or less, more preferably 0.02% by mass or more and 0.5% by mass or less. When the residual diisocyanate concentration is in such a range, the toxicity is low and the curability tends to be sufficient. The residual diisocyanate concentration can be measured by the method described in the examples described later.

[Diisocyanate]
The diisocyanate that is a raw material of the polyisocyanate contained in the polyisocyanate composition of the present embodiment is one or more diisocyanates selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates.
In the present embodiment, the “aliphatic diisocyanate” refers to a compound having two isocyanate groups and a chain aliphatic hydrocarbon in the molecule and having no aromatic hydrocarbon.
Although it does not specifically limit as aliphatic diisocyanate, A C4-C30 thing is preferable, for example, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate (henceforth "HDI"), 2,2,4 -Trimethyl-1,6-hexamethylene diisocyanate, lysine diisocyanate and the like. Among these, HDI is more preferable from the viewpoint of industrial availability. The aliphatic diisocyanates shown above may be used alone or in combination of two or more.

In the present embodiment, “alicyclic diisocyanate” refers to a compound having two isocyanate groups and a cyclic aliphatic hydrocarbon having no aromaticity in the molecule.
Although it does not specifically limit as alicyclic diisocyanate, A C8-C30 thing is preferable, for example, isophorone diisocyanate (henceforth "IPDI"), 1, 3-bis (isocyanatomethyl) -cyclohexane, 4,4′-dicyclohexylmethane diisocyanate, norbornene diisocyanate, hydrogenated xylylene diisocyanate, and the like. Among these, IPDI is more preferable because of weather resistance and industrial availability. The alicyclic diisocyanates shown above may be used alone or in combination of two or more.

[Polycaprolactone polyol]
The polycaprolactone polyol, which is a raw material of the polyisocyanate contained in the polyisocyanate composition of the present embodiment, is a divalent to tetravalent polyol containing a repeating unit represented by —O (CH ₂ ) ₅ CO—. For example, it can be derived from a divalent to tetravalent alcohol and ε-caprolactone.

The polycaprolactone polyol can be obtained, for example, by subjecting ε-caprolactone to ring-opening polymerization in the presence of a catalyst using a divalent to tetravalent alcohol as an initiator.
As the initiator, divalent alcohol: ethylene glycol, propylene glycol, 1,3-butylene glycol, neopentyl glycol, etc., trivalent alcohol: trimethylene glycol, glycerin, tetravalent alcohol: pentaerythritol are used. From the viewpoint of obtaining a low-viscosity polyisocyanate composition, branched polyhydric alcohols are preferred.
The catalyst is preferably an organic titanium compound such as tetrabutyl titanate, tetrapropyl titanate or tetraethyl titanate, or a tin compound such as tin octylate, dibutyltin oxide, dibutyltin laurate, stannous chloride or stannous bromide. Used. From the viewpoint of adjusting the caprolactone dimer content to the range specified in the present application, a tin-based compound is preferable.
The ring-opening polymerization of ε-caprolactone is charged with a molar ratio of ε-caprolactone and the above initiator so as to have a predetermined molecular weight in a nitrogen gas atmosphere, and further 0.1 ppm or more of catalyst relative to ε-caprolactone. It is preferable to add 100 ppm or less and react at a temperature of 150 ° C. or more and 200 ° C. or less for 4 hours or more and 10 hours or less. However, it is important to control the caprolactone dimer content at 100 to 1000 ppm at the end point of the reaction. If necessary, caprolactone dimer may be removed from the produced polycaprolactone polyol by a method such as extraction or distillation.
In addition to ε-caprolactone, other cyclic lactones such as trimethylcaprolactone and valerolactone may be partially mixed.

[Polyisocyanate]
The polyisocyanate in the present embodiment includes at least an isocyanurate bond, and is not particularly limited. For example, biuret bond, urea bond, uretdione bond, urethane bond, allophanate bond, iminooxadiazine dione bond, oxadiazine It may have a trione bond or the like.

A polyisocyanate having an isocyanurate bond is obtained by, for example, carrying out a cyclic trimerization reaction with a catalyst or the like, stopping the reaction when the conversion rate is about 5 to about 80% by mass, and removing and purifying unreacted diisocyanate. . In this embodiment, in this case, in addition to polycaprolactone polyol, 1 to 6-valent alcohol compounds such as 1,3-butanediol and trimethylolpropane can be used in combination.
As the catalyst for producing the polyisocyanate having an isocyanurate bond, a catalyst having basicity is generally preferable. Examples of such catalysts include (1) tetraalkylammonium hydroxides such as tetramethylammonium, tetraethylammonium, tetrabutylammonium, and trimethylbenzylammonium, organic weak acid salts such as acetic acid and capric acid, (2 ) Hydroxyalkylammonium hydroxides such as trimethylhydroxypropylammonium, trimethylhydroxyethylammonium, triethylhydroxypropylammonium, triethylhydroxyethylammonium, etc., organic weak acid salts such as acetic acid and capric acid, and (3) alkylcarboxylic acid such as tin Alkyl metal salts such as zinc and lead, (4) metal alcoholates such as sodium and potassium, and (5) aminosilyl group-containing compounds such as hexamethyldisilazane , (6) Mannich bases, (7) in combination with tertiary amines with epoxy compounds, (8) phosphorus compounds such as tributylphosphine and the like, may be used in combination of two or more of these.
When the catalyst may adversely affect the properties of the paint or coating film, it is preferable to neutralize the catalyst with an acidic compound or the like. The acidic compound in this case is not particularly limited. For example, inorganic acids such as hydrochloric acid, phosphorous acid, phosphoric acid; methanesulfonic acid, p-toluenesulfonic acid, p-toluenesulfonic acid methyl ester, p-toluenesulfonic acid ethyl Sulfonic acids such as esters or derivatives thereof; ethyl phosphate, diethyl phosphate, isopropyl phosphate, diisopropyl phosphate, butyl phosphate, dibutyl phosphate, 2-ethylhexyl phosphate, di (2-ethylhexyl) phosphate, isodecyl phosphate, diisodecyl phosphate, oleyl acid phosphate, Examples include tetracosyl acid phosphate, ethyl glycol acid phosphate, butyl pyrophosphate, and butyl phosphite, and two or more of these may be used in combination.

[Block polyisocyanate composition]
The polyisocyanate composition of the present embodiment may be a blocked polyisocyanate composition by blocking at least part of the isocyanate groups of the polyisocyanate contained in the composition with a blocking agent.
There is no limitation on the blocking agent that can be used in the present embodiment, for example, various blocks such as alcohol, phenol, oxime, amine, acid amide, imidazole, pyridine, mercaptan, and active methylene compounds. An agent can be used.
The blocking reaction can generally be carried out at -20 to 150 ° C, preferably 0 to 100 ° C. If the temperature is 150 ° C. or higher, side reactions may occur, and if the temperature is too low, the reaction rate decreases, which is disadvantageous. It is preferably blocked so that substantially active isocyanate groups are eliminated.
The blocking reaction can be performed with or without the presence of a solvent. When using a solvent, it is preferable to use a solvent inert to the isocyanate group.
In the blocking reaction, organometallic salts such as tin, zinc and lead, metal alcoholates such as sodium methylate, sodium ethylate, sodium phenolate and potassium methylate, and tertiary amines may be used as catalysts.
Moreover, you may neutralize at least one part of the catalyst used for said blocking reaction with the following acidic compound. Neutralization is preferable because the thermal stability of the block polyisocyanate composition is improved. Examples of acidic compounds include inorganic acids such as hydrochloric acid, phosphorous acid, and phosphoric acid, sulfonic acids such as methanesulfonic acid and p-toluenesulfonic acid, ethyl phosphate, diethyl phosphate, isopropyl phosphate, diisopropyl phosphate, butyl phosphate, and dibutyl phosphate. Examples thereof include phosphate esters such as 2-ethylhexyl phosphate and di (2-ethylhexyl) phosphate. In addition, the range of 0.3-3 equivalent is preferable with respect to a catalyst, as for an acidic compound, More preferably, it is 0.5-2 equivalent, More preferably, it is 0.7-1.5 equivalent.

[Coating composition]
The one-component coating composition of this embodiment includes the above-described blocked polyisocyanate composition and a polyvalent active hydrogen compound, and the two-component coating composition includes an unblocked polyisocyanate composition and a polyvalent active hydrogen compound. Active hydrogen compounds.

[Polyvalent active hydrogen compound]
In the present embodiment, the polyvalent active hydrogen compound used in the coating composition is not particularly limited, but preferably includes at least one selected from the group consisting of polyols, polyamines, and alkanolamines. More preferably, it contains a polyol.
Although it does not specifically limit as a polyol, For example, polyester polyol, acrylic polyol, polyether polyol, polyolefin polyol, fluorine polyol, polycarbonate polyol, and polyurethane polyol are mentioned. The polyols shown above may be used alone or in combination of two or more.

  The polyester polyol is not particularly limited, but for example, one or more selected from the group consisting of carboxylic acids such as succinic acid, adipic acid, sebacic acid, dimer acid, maleic anhydride, phthalic anhydride, isophthalic acid, terephthalic acid, or the like Polyester obtained by a condensation reaction between two or more dibasic acids and one or more polyhydric alcohols selected from the group consisting of ethylene glycol, propylene glycol, diethylene glycol, neopentyl glycol, trimethylolpropane, and glycerin Examples thereof include polycaprolactones obtained by ring-opening polymerization of ε-caprolactone using a polyol and, for example, a polyhydric alcohol.

The acrylic polyol is not particularly limited, but for example, an ethylenically unsaturated bond-containing monomer having a hydroxyl group alone or a mixture thereof, and another ethylenically unsaturated bond-containing monomer copolymerizable therewith or It is obtained by copolymerizing the mixture.
The ethylenically unsaturated bond-containing monomer having a hydroxyl group is not particularly limited, and examples thereof include hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, and methacrylic acid. Examples include hydroxybutyl acid. Preferred are hydroxyethyl acrylate and hydroxyethyl methacrylate.
Other ethylenically unsaturated bond-containing monomers copolymerizable with the above monomers are not particularly limited. For example, methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, acrylic acid-n -Acrylic acid esters such as butyl, isobutyl acrylate, acrylic acid-n-hexyl, cyclohexyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, benzyl acrylate, phenyl acrylate; methyl methacrylate, ethyl methacrylate, Propyl methacrylate, isopropyl methacrylate, methacrylic acid-n-butyl, methacrylic acid isobutyl, methacrylic acid-n-hexyl, cyclohexyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, benzyl methacrylate, methacrylate Methacrylic acid esters such as phenyl uric acid; Unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, itaconic acid; acrylamide, methacrylamide, N, N-methylenebisacrylamide, diacetone acrylamide, diacetone methacrylamide, malee Unsaturated amides such as acid amides and maleimides; vinyl monomers such as glycidyl methacrylate, styrene, vinyl toluene, vinyl acetate, acrylonitrile, dibutyl fumarate; vinyl trimethoxysilane, vinylmethyldimethoxysilane, γ- (meth) Examples thereof include vinyl monomers having a hydrolyzable silyl group such as acryloxypropyltrimethoxysilane.

The polyether polyol is not particularly limited, but for example, using a polybasic hydroxy compound alone or in a mixture, a hydroxide such as lithium, sodium, or potassium, or a strongly basic catalyst such as alcoholate or alkylamine, Polyether polyols obtained by adding a single or mixture of alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, cyclohexene oxide, styrene oxide or the like; polyalkylene compounds obtained by reacting alkylene oxide with a polyfunctional compound such as ethylenediamine Ether polyols; so-called polymer polyols obtained by polymerizing acrylamide or the like using these polyethers as a medium.
As the above polyvalent hydroxy compound,
(1) Diglycerin, ditrimethylolpropane, pentaerythritol, dipentaerythritol, etc.
(2) sugar alcohol compounds such as erythritol, D-threitol, L-arabinitol, ribitol, xylitol, sorbitol, mannitol, galactitol, rhamnitol,
(3) monosaccharides such as arabinose, ribose, xylose, glucose, mannose, galactose, fructose, sorbose, rhamnose, fucose, ribodesose,
(4) disaccharides such as trehalose, sucrose, maltose, cellobiose, gentiobiose, lactose, melibiose,
(5) trisaccharides such as raffinose, gentianose, and meletitose,
(6) Tetrasaccharides such as stachyose can be mentioned.

  The polyolefin polyol is not particularly limited, and examples thereof include polybutadiene having two or more hydroxyl groups, hydrogenated polybutadiene, polyisoprene, and hydrogenated polyisoprene. The number of hydroxyl groups (hereinafter, also referred to as “average number of hydroxyl groups”) possessed by one statistical molecule of polyol is preferably 2.0 or more. When the hydroxyl group average number of the polyol is 2.0 or more, there is a tendency that a decrease in the crosslinking density of the obtained coating film can be suppressed.

  Fluorine polyol is a polyol containing fluorine in the molecule. For example, fluoroolefin, cyclovinyl ether, hydroxyalkyl vinyl ether, monocarboxylic acid disclosed in JP-A-57-34107 and JP-A-61-275111. Examples include copolymers such as acid vinyl esters.

  The polycarbonate polyol is not particularly limited, and examples thereof include dialkyl carbonates such as dimethyl carbonate; alkylene carbonates such as ethylene carbonate; low molecular carbonate compounds such as diaryl carbonates such as diphenyl carbonate; And those obtained by condensation polymerization.

  Although it does not specifically limit as a polyurethane polyol, For example, it can obtain by making a polyol and polyisocyanate react by a conventional method. Examples of the polyol not containing a carboxyl group include ethylene glycol and propylene glycol as low molecular weights, and examples of the high molecular weight include acrylic polyol, polyester polyol, and polyether polyol.

The hydroxyl value per resin of the polyol shown above is preferably 10 mgKOH / resin g or more and 300 mgKOH / resin g or less. When the hydroxyl value per resin is 10 mgKOH / resin g or more, the crosslinking density is prevented from decreasing and the intended physical properties tend to be sufficiently achieved. On the other hand, when the hydroxyl value per resin is 300 mgKOH / resin g or less, the crosslinking density is prevented from excessively increasing, and the mechanical properties of the coating film tend to be maintained at a high level.
Of the polyols listed above, acrylic polyols and polyester polyols are preferred. When a polyol is used as the polyvalent active hydrogen compound, the equivalent ratio of the blocked isocyanate group to the hydroxyl group of the polyol in the one-pack type coating composition is preferably 10: 1 to 1:10. Moreover, it is preferable that the equivalent ratio of the isocyanate group and the hydroxyl group of a polyol in a two-pack type coating composition is 10: 1 to 1:10.

Although it does not specifically limit as a polyamine, What has 2 or more primary amino groups or secondary amino groups in 1 molecule is preferable, and what has 3 or more in 1 molecule among these is more preferable.
Although it does not specifically limit as a specific example of polyamine, For example, diamine, such as ethylenediamine, propylenediamine, butylenediamine, triethylenediamine, hexamethylenediamine, 4,4'-diaminodicyclohexylmethane, piperazine, 2-methylpiperazine, isophoronediamine Chain polyamines having three or more amino groups such as bishexamethylenetriamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentamethylenehexamine, tetrapropylenepentamine; 1,4,7,10,13 , 16-hexaazacyclooctadecane, 1,4,7,10-tetraazacyclodecane, 1,4,8,12-tetraazacyclopentadecane, 1,4,8,11-tetraazacyclotetradecane, etc. Of the cyclic polyamines.

  Alkanolamine is a compound having an amino group and a hydroxyl group in one molecule. The alkanolamine is not particularly limited, and examples thereof include monoethanolamine, diethanolamine, aminoethylethanolamine, N- (2-hydroxypropyl) ethylenediamine, mono-, di- (n- or iso-) propanolamine, and ethylene glycol. -Bis-propylamine, neopentanolamine, and methylethanolamine.

The two-component coating composition and the one-component coating composition of the present embodiment include an antioxidant such as hindered phenol, an ultraviolet absorber such as benzotriazole and benzophenone, titanium oxide, carbon black, and indigo as required. Further, pigments such as quinacridone and pearl mica, metal powder pigments such as aluminum, rheology control agents such as hydroxyethyl cellulose, urea compounds and microgels, and curing accelerators such as tin compounds, zinc compounds and amine compounds may be further included.
The two-component coating composition and the one-component coating composition of the present embodiment are formed by roll coating, curtain flow coating, spray coating, electrostatic coating, bell coating, etc. It can be suitably used as a primer, intermediate coating or top coating on a material such as an inorganic material. In addition, these coating compositions further impart cosmetics, weather resistance, acid resistance, rust resistance, chipping resistance, adhesion, etc. to pre-coated metals, automobile coatings, plastic coatings, etc. that contain rust-proof steel sheets. Can be suitably used. Furthermore, these coating compositions are also useful as raw materials for urethane such as adhesives, pressure-sensitive adhesives, elastomers, foams, and surface treatment agents.

[Coating film, article with coating film]
In this embodiment, a coating film can be formed on various articles by applying the two-component coating composition or the one-component coating composition described above.
As an article provided with the coating film of this embodiment, a car etc. are mentioned, for example.
The coating method is not particularly limited. For example, the two-component coating composition or the one-component coating composition of this embodiment is applied by roll coating, curtain flow coating, spray coating, electrostatic coating, bell coating, or the like. A coating film can be formed by performing a baking process after coating. It is preferable that a crosslinked coating film is formed on this coating film through a baking step.

  Hereinafter, the present embodiment will be described in more detail by way of examples. However, the present embodiment is not limited to these examples.

It shows below about the measuring method of the various physical properties of the polyisocyanate composition in an Example and a comparative example.
(Physical property 1) NCO content (mass%)
The NCO content (isocyanate group content, mass%) of the polyisocyanate composition obtained by removing the unreacted diisocyanate, which was obtained in Examples and Comparative Examples, was measured as follows.
1 to 3 g of the polyisocyanate composition produced in the production example was precisely weighed (Wg) in an Erlenmeyer flask, and 20 mL of toluene was added thereto to completely dissolve the polyisocyanate composition. Thereafter, 10 mL of a 2N di-n-butylamine toluene solution was added, thoroughly mixed, and allowed to stand at room temperature for 15 minutes. Further, 70 mL of isopropyl alcohol was added to this solution and mixed thoroughly. This solution was titrated with a 1 N hydrochloric acid solution (factor F) using an indicator to obtain a titration value V ₂ mL.
The same titration operation was performed without using the polyisocyanate composition, and a titration value V ₁ mL was obtained.
From the obtained titration value V ₂ mL and titration value V ₁ mL, the NCO content of the polyisocyanate composition was calculated based on the following formula.
NCO content = (V ₁ −V ₂ ) × F × 42 / (W × 1000) × 100

(Physical property 2) Viscosity (mPa.s)
The viscosity at 25 ° C. of the polyisocyanate composition was measured at 25 ° C. using an E-type viscometer (trade name: RE-80U, manufactured by Toki Sangyo Co., Ltd.). For the measurement, a high viscosity rotor (3 ° × R14) was used. The number of revolutions was set as follows.
100r. p. m. (In the case of less than 4940 mPa.s)
50r. p. m. (In the case of 4940 mPa.s or more and less than 9870 mPa.s)
20r. p. m. (In the case of 9870 mPa.s or more and less than 24690 mPa.s)
10r. p. m. (In the case of 24690 mPa.s or more and less than 49380 mPa.s)
5r. p. m. (In the case of 49380 mPa.s or more and less than 98770 mPa.s)
2.5r. p. m. (In the case of 98770 mPa.s or more and less than 1975540 mPa.s)
1.0r. p. m. (In the case of 1975540 mPa.s or more and less than 395050 mPa.s)
0.5r. p. m. (In the case of 395050 mPa.s or more and less than 790100 mPa.s)

(Physical property 3) Number average molecular weight The number average molecular weight of polyisocyanate was calculated | required by the number average molecular weight of the polystyrene reference | standard by the gel permeation chromatograph (henceforth "GPC") measurement using the following apparatus.
Equipment: “HLC-8120GPC” (trade name) manufactured by Tosoh Corporation
Column: "TSKgel SuperH1000" (product name) x 1 manufactured by Tosoh Corporation
"TSKgel SuperH2000" (trade name) x 1
“TSKgel SuperH3000” (trade name) × 1 Carrier: Tetrahydrofuran Detection method: Differential refractometer The number average molecular weight of the polyol was determined by the polystyrene-based number average molecular weight by the following GPC measurement.
Equipment: “HLC-8120GPC” (trade name) manufactured by Tosoh Corporation
Column: “TSKgel SuperHM-H (trade name)” x 2 manufactured by Tosoh Corporation Carrier: N, N-dimethylformamide Detection method: differential refractometer

(Physical Property 4) Average Number of Isocyanate Groups The average number of isocyanate groups in the polyisocyanate was calculated based on the following formula from the above (Physical property 1) NCO content and (Physical property 3) number average molecular weight.
Isocyanate group average number = number average molecular weight × (NCO content / 100) / 42

(Physical property 5) Residual diisocyanate concentration (mass%)
The residual diisocyanate concentration of the polyisocyanate composition was determined as follows.
First, a 20 mL sample bottle was placed on a digital balance, and about 1 g of the sample was precisely weighed. Next, 0.03-0.04 g of nitrobenzene (internal standard solution) was added and precisely weighed. Finally, after adding about 9 mL of ethyl acetate, the lid was tightly mixed well to prepare the sample. The adjustment liquid was quantitatively analyzed by gas chromatography under the following conditions.
Apparatus: “GC-8A” manufactured by SHIMADZU
Column: “Silicon OV-17” manufactured by Shinwa Kako
Column oven temperature: 120 ° C
Injection / detector temperature: 160 ° C

(Physical property 6) Presence or absence of isocyanurate bond The presence or absence of the isocyanurate bond of polyisocyanate was measured by ¹³ C-NMR measurement using Biospin Avance 600 (trade name) manufactured by Bruker. Specifically, the presence or absence of a peak near 148.6 ppm was confirmed.
Specific measurement conditions were as follows.
¹³ C-NMR apparatus: AVANCE 600 (manufactured by Bruker)
Cryoprobe (Bruker)
Cryo Probe
CPDUUL
600S3-C / HD-05Z
Resonance frequency: 150 MHz
Concentration: 60 wt / vol%
Shift standard: CDCl ₃ (77 ppm)
Integration count: 10,000 times

(Physical property 7) Trimer concentration In the GPC measurement shown in the above (Physical property 3) number average molecular weight, the trimer concentration was quantified.
A peak area% corresponding to a molecular weight three times that of the diisocyanate used as a raw material was defined as a trimer concentration.

The evaluation methods for various physical properties of the polyisocyanate compositions and the coating compositions containing them in the examples and comparative examples are shown below.
(Evaluation 1) Moisture stability A mixed solvent of 30 parts by mass of n-butyl acetate and 30 parts by mass of xylene containing 40 parts by mass of a polyisocyanate composition and 0.2 parts by mass of water was mixed. The sample was left in a room kept at a temperature of 23 ° C., and the number of days until the appearance became cloudy was visually observed.
○: No cloudiness for 10 days or more ×: Cloudiness within 10 days

(Evaluation 2) Curability Curability was evaluated by forming a coating film of a two-component coating composition on a polypropylene plate and measuring the gel fraction of the film obtained by peeling it from the plate. Specifically, the cured coating film baked for 30 minutes in an oven maintained at 120 ° C. was peeled off from the polypropylene plate, and the weight residual ratio when immersed in acetone at 23 ° C. for 24 hours was determined.
○: Weight residual ratio is 90% or more Δ: Weight residual ratio is 80% or more and less than 90% ×: Weight residual ratio is less than 80%

(Evaluation 3) Adhesiveness With respect to the coating film of the two-component coating composition prepared on the mild steel sheet, an adhesiveness test was performed according to JIS K5600-5-6. Evaluation was made according to the following criteria.
○: Peeling paint film, no lift △: Partly lifted at the cut part ×: Peeling paint film less than half

(Evaluation 4) Weather resistance A commercially available solvent-based two-component acrylic urethane white enamel paint was spray-coated on an aluminum plate in advance, dried at 80 ° C for 2 hours after setting, and cured at room temperature for 2 weeks or more, and glossed at 60 ° C. A white plate whose surface was polished with sandpaper of # 1000 until the value became 10% or less was prepared as a base material.
The two-component coating composition was applied onto the substrate using an air spray and dried for 7 days in an atmosphere of 23 ° C./50% RH. Then, it evaluated on the conditions of JISK5600-7-7 using Suga Test Instruments Co., Ltd. super xenon weather meter SX75.
◎: 60 degree gloss retention after exposure for 3000 hours is 90% or more ○: 60 degree gloss retention after 3000 hours exposure is from 80% to less than 90% Δ: 60 degree gloss retention after 3000 hours exposure 70% or more and less than 80% x: 60 degree gloss retention after exposure for 3000 hours is less than 70%

[Production Example 1: Polycaprolactone polyol A]
The inside of a four-necked flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen blowing tube was put in a nitrogen atmosphere, ε-caprolactone: 499 parts by mass, trimethylolpropane: 402 parts by mass, tetrabutyl titanate: 0.02 A mass part was charged and reacted at 170 ° C. for 5 hours with stirring to obtain a polycaprolactone polyol A having a hydroxyl value of 540 and a caprolactone dimer content of 3800 ppm.
Here, the quantification of caprolactone dimer content was determined using a FID detection type GC (trade name) equipped with a column using 5% SE-30 (trade name), Cameraite CS (trade name), and 80 to 100 mesh as a filler. GC-9A: manufactured by Shimadzu Corporation), injection temperature: 230 ° C., column temperature: 220 ° C., detector temperature: 230 ° C., carrier gas: helium, carrier gas flow rate: 50 mL / min, polycaprolactone polyol 1 From the result of analyzing 1.0 μL of a sample solution prepared by dissolving .000 g in acetone (special grade reagent) in a 20 mL volumetric flask, an absolute calibration curve method was used.

[Adjustment Example 1: Polycaprolactone polyol (PCL) -A1 to A5]
In order to adjust the caprolactone dimer content in the polycaprolactone polyol A obtained in Production Example 1, polycaprolactone polyol A was dissolved in tetrahydrofuran (hereinafter THF), and the caprolactone dimer was extracted with n-hexane. After extraction, THF was distilled off and vacuum-dried, so that the caprolactone dimer contents were 950 ppm (PCL-A1), 680 ppm (PCL-A2), 260 ppm (PCL-A3), 140 ppm (PCL-A4), respectively. Polycaprolactone polyols PCL-A1 to A5, which are 60 ppm (PCL-A5), were obtained.

[Production Example 2: Polycaprolactone polyol B]
The inside of a four-necked flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen blowing tube was put in a nitrogen atmosphere, ε-caprolactone: 624 parts by mass, trimethylolpropane: 201 parts by mass, tetrabutyl titanate: 0.02 A mass part was charged and reacted at 170 ° C. for 10 hours with stirring to obtain a polycaprolactone polyol B having a hydroxyl value of 305 and a caprolactone dimer content of 6500 ppm.

[Adjustment Example 2: Polycaprolactone polyol PCL-B1 to B2]
In order to adjust the caprolactone dimer content in the polycaprolactone polyol B obtained in Production Example 2, polycaprolactone polyol B was dissolved in tetrahydrofuran (hereinafter referred to as THF), and the caprolactone dimer was extracted with n-hexane. After extraction, THF was distilled off and vacuum drying was performed to obtain polycaprolactone polyols PCL-B1 and B2 having caprolactone dimer contents of 530 ppm (PCL-B1) and 320 ppm (PCL-B2), respectively. .

[Example 1: Production of polyisocyanate composition P-1]
The inside of a four-necked flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen blowing tube was put into a nitrogen atmosphere, and hexamethylene diisocyanate (HDI): 1000 parts by mass, PCL-A1: 100 parts by mass were charged with stirring. The reactor internal temperature was maintained at 90 ° C. for 1 hour. Thereafter, the temperature in the reactor was kept at 80 ° C., tetrabutylammonium acetate was added to start isocyanurate conversion, and when the NCO content of the reaction solution reached 33.8% by mass (of tetrabutylammonium acetate After 4 hours from the addition, phosphoric acid was added to stop the reaction.
After the reaction solution was filtered, unreacted HDI was removed using a thin film evaporator, and the NCO content was 18.2% by mass and the viscosity at 25 ° C. was 22000 mPa.s. s, number average molecular weight: 1320, isocyanate group average number: 5.7, residual HDI: 0.1% by mass, polyisocyanate composition P-1 containing isocyanurate bond and having a trimer concentration of 19% by mass is obtained. It was.
When the caprolactone dimer content in the polyisocyanate composition P-1 was quantified in the same manner as in the case of the polycaprolactone polyol described above, it was 485 ppm.

(Evaluation of moisture stability)
The obtained polyisocyanate composition P-1 was evaluated for moisture stability. The evaluation results are shown in Table 1.

(Evaluation of curability, adhesion, weather resistance)
Polyisocyanate composition P-1 has an NCO / OH ratio of 1 with respect to acrylic polyol (trade name: SETALUX 1767, manufactured by Nuplex, hydroxyl value = 150 mg KOH / g (solid content), resin concentration = 65 mass%). 0.02 and the solid content of the paint was adjusted to 50% by mass with butyl acetate to obtain a two-pack type coating composition.
Using the two-pack type coating composition, coating films were prepared on a polypropylene plate, a mild steel plate, and a white plate, respectively, so as to have a dry film thickness of about 50 μm. The resulting coating film was evaluated for curability, adhesion, and weather resistance. The evaluation results are shown in Table 1.

[Examples 2-6, Comparative Examples 1-5]
A polyisocyanate composition was obtained in the same manner as in Example 1 except that the composition and conditions shown in Table 1 were used. Table 1 shows various measured values and physical property evaluation results for the obtained polyisocyanate composition.

  The polyisocyanate composition and coating composition of the present invention can be used as a raw material for paints, inks, adhesives, casting materials, elastomers, foams, and plastic materials. Among these, it is suitable for automobile paints, home appliance paints, information equipment paints such as personal computers and mobile phones.

Claims (9)

(1) Polyisocyanate obtained from at least one diisocyanate selected from the group consisting of an aliphatic diisocyanate and an alicyclic diisocyanate, and (2) a polycaprolactone polyol having a valence of 2 to 4 and containing an isocyanurate bond. Including
The caprolactone dimer content is 50 ppm or more and 500 ppm or less,
Polyisocyanate composition.   The polyisocyanate composition according to claim 1, wherein the trimer concentration is 2% by mass or more and 40% by mass or less.   The polyisocyanate composition according to claim 1 or 2, wherein the (2) polycaprolactone polyol is trivalent and has a number average molecular weight of 250 or more and 2000 or less. When measured in a state not containing diisocyanate and solvent, the NCO content is 10% by mass or more and 24% by mass or less, and the viscosity at 25 ° C. is 5000 mPa.s. s to 1,000,000 mPa.s s or less,
The polyisocyanate composition according to any one of claims 1 to 3, wherein an average number of isocyanate groups of the polyisocyanate is 4.5 or more and 10 or less.   A two-component coating composition comprising the polyisocyanate composition according to any one of claims 1 to 4 and a polyvalent active hydrogen compound.   The polyisocyanate composition according to any one of claims 1 to 4, wherein at least a part of the isocyanate groups of the polyisocyanate is blocked with a blocking agent.   A one-component coating composition comprising the polyisocyanate composition according to claim 6 and a polyvalent active hydrogen compound.   A method for forming a coating film comprising a step of applying the two-component coating composition according to claim 5 or the one-component coating composition according to claim 7.   The manufacturing method of the articles | goods provided with a coating film including the process of apply | coating the two-component coating composition of Claim 5, or the one-component coating composition of Claim 7.