JP2017165813A - Polyisocyanate composition, coating composition and method for producing coated body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a polyisocyanate composition that exhibits a high drying property and further has an excellent property in moisture stability and compatibility with polyol; a coating composition comprising the same; and a coating method.SOLUTION: Provided is a polyisocyanate composition obtained from one or more diisocyanates selected from aliphatic diisocyanates and alicyclic diisocyanates, and one or more diols, and in which the mole ratio of urea group/(urea group + isocyanurate group) in the polyisocyanate composition is 0.0001 to 0.1 and the mole ratio of allophanate group/(isocyanurate group + allophanate group) is 0.2 to 0.9.SELECTED DRAWING: None

Description

  The present invention relates to a polyisocyanate composition, a coating composition, and a method for producing a coated body.

  Conventionally, polyurethane resin paints are known to have excellent wear resistance, chemical resistance, and stain resistance. In particular, polyurethane resin paints using non-yellowing polyisocyanate derived from hexamethylene diisocyanate or isophorone diisocyanate are used. Has even better weather resistance. Therefore, the use of such polyisocyanate is in the form of a two-component urethane coating at room temperature or thermosetting, and is widely used in construction, heavy protection, automobiles, industrial use and repairs thereof. In each use, an improvement in curability is desired in order to shorten the process.

  In order to improve curability, for example, there is a method of adding an organic tin compound or the like. However, this method may have different effects depending on the composition of the paint, and combustion of an organic solvent processing apparatus that volatilizes by coating or the like. It has problems such as adversely affecting the catalyst.

  On the other hand, in order to solve these problems, development of highly functional polyisocyanate has been promoted.

  In Patent Document 1, a highly functional polyisocyanate is obtained by isocyanuration after reaction of at least one aliphatic or alicyclic diisocyanate with a polyfunctional alcohol, or by isocyanuration in the presence of such alcohol. Has been proposed.

JP-A-6-312969

  When using the polyisocyanate mixed with the main agent, if the required amount is small, the same can is opened and closed many times, so the isocyanate group reacts with moisture in the air. ing. Also, the block polyisocyanate composition that is not compatible with some polyols, especially when used as a curing agent for transparent paints, the coating film may be turbid and has excellent compatibility with polyols. Things are sought. The polyisocyanate described in Patent Document 1 has high drying properties, but may be insufficient in moisture stability and compatibility with polyols.

  The present invention has been made in view of the above-described problems of the prior art, and shows a polyisocyanate composition exhibiting high drying properties and having excellent performance in moisture stability and compatibility with polyols, and a coating material containing the same An object is to provide a composition and a coating method.

  As a result of intensive studies to solve the above problems, the present inventors have found that a polyisocyanate composition having a predetermined functional group at a specific ratio solves the above problems, and has completed the present invention. .

That is, the present invention is as follows.
[1]
A polyisocyanate composition obtained from one or more diisocyanates and one or more diols selected from aliphatic diisocyanates and alicyclic diisocyanates,
In the polyisocyanate composition, the molar ratio of urea group / (urea group + isocyanurate group) is 0.0001 to 0.1, and the molar ratio of allophanate group / (isocyanurate group + allophanate group) is 0.00. A polyisocyanate composition which is 2 to 0.9.
[2]
The polyisocyanate composition according to [1], wherein the allophanate group / (allophanate group + urethane group) molar ratio is 0.6 to 1.0.
[3]
The polyisocyanate composition according to [1] or [2], wherein the number average functional group number is 3.8 to 10.0.
[4]
Polyisocyanate composition in any one of [1]-[3] whose isocyanate group concentration is 14.0-21.0 mass%.
[5]
The polyisocyanate composition according to any one of [1] to [4], wherein the viscosity at 25 ° C is 8,000 to 50,000 mPa · s.
[6]
[1] A coating composition comprising the polyisocyanate composition according to any one of [5] and at least one polyol.
[7]
The manufacturing method of a coating body including the process of apply | coating the coating composition as described in [6] on a base material.

  ADVANTAGE OF THE INVENTION According to this invention, the polyisocyanate composition which shows high drying property and can achieve the further excellent moisture stability and compatibility with a polyol can be provided.

  DESCRIPTION OF EMBODIMENTS Hereinafter, a mode for carrying out the present invention (hereinafter referred to as “the present embodiment”) will be described in detail. However, the present invention is not limited to this, and various modifications can be made without departing from the gist thereof. Is possible.

[Polyisocyanate composition]
The polyisocyanate composition of the present embodiment is a polyisocyanate composition obtained from one or more diisocyanates selected from aliphatic diisocyanates and alicyclic diisocyanates and one or more diols, and the urea group in the polyisocyanate composition The molar ratio of / (urea group + isocyanurate group) is 0.0001 to 0.1, and the molar ratio of allophanate group / (isocyanurate group + allophanate group) is 0.2 to 0.9.
Since it is comprised in this way, the polyisocyanate composition of this embodiment can show high drying property, and also can achieve the outstanding moisture stability and compatibility with a polyol.

(Diisocyanate)
The diisocyanate that can be used in the present embodiment is at least one selected from aliphatic diisocyanates and alicyclic diisocyanates. Although it does not specifically limit as aliphatic diisocyanate, A C4-C30 thing is preferable. Moreover, although alicyclic diisocyanate is not specifically limited, A C8-C30 thing is preferable. Specific examples of the diisocyanate include, but are not limited to, 1,4-butane diisocyanate, 1,5-pentane diisocyanate, 1,6-hexamethylene diisocyanate, 2,2,4-trimethyl-hexamethylene-1,6. -Diisocyanate, lysine diisocyanate, isophorone diisocyanate, 1,3-bis (isocyanatemethyl) -cyclohexane, 4,4'-dicyclohexylmethane diisocyanate and the like. Among these, 1,6-hexamethylene diisocyanate (hereinafter referred to as HDI) is preferable because it has good weather resistance and reactivity and tends to lower the viscosity of the resulting polyisocyanate composition. These may be used alone or in combination.

(Diol)
The alcohol constituting the allophanate group and the urethane group in the polyisocyanate composition of the present embodiment includes a diol from the viewpoint of improving the compatibility with the polyol and the curability when the coating composition is used.

  Examples of the diol include, but are not limited to, for example, ethylene glycol, 1,3-propanediol, 1,2-propanediol, 1,3-butanediol, 1,4-butane, which are linear aliphatic diols. Diol, 2,3-butanediol, 1,5-pentanediol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol, neopentyl glycol, 1,6-hexanediol, 1, 7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, diethylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and branched aliphatic diol 2 -Methyl 1,3-propanediol, 3-methyl-1,5 Pentanediol, 2-methyl-1,8-octanediol, and 2,2-diethyl-1,3-propanediol. These may be used alone or in combination of two or more. Among them, the lower limit of the carbon number of the diol is preferably 2. By being 2 or more, the number average functional group number tends to be high, and the curability and drying property tend to be better. On the other hand, the upper limit is preferably 10, more preferably 6. When it is 10 or less, the compatibility becomes better, and the appearance of the coating film tends to be further improved.

  Although the density | concentration of the diol component which comprises the polyisocyanate composition of this embodiment is not specifically limited, It is preferable that it is 1 mass% or more with respect to a polyisocyanate component, More preferably, it is 2 mass% or more. On the other hand, the upper limit of the concentration is preferably 20% by mass, and more preferably 10% by mass. When the component concentration of the diol is 1% by mass or more and 20% by mass or less, the molar ratio of allophanate group / (isocyanurate group + allophanate group) described later is in a preferable range, and the compatibility with the main ingredient tends to be good. . The diol component concentration can be determined by measuring 1H-NMR.

(Urea group / (Urea group + isocyanurate group))
The polyisocyanate composition of the present embodiment includes a urea group represented by the following formula (1) and an isocyanurate group represented by the following formula (2).

  The content ratio of the urea group to the isocyanurate group is 0.0001 or more and 0.1 or less in terms of a molar ratio of urea group / (urea group + isocyanurate group). The molar ratio is preferably 0.0005 or more, and more preferably 0.001 or more. Moisture stability becomes favorable because the said molar ratio is 0.0001 or more. The molar ratio is preferably 0.07 or less, and more preferably 0.05 or less. Heat resistance becomes favorable because the said molar ratio is 0.1 or less.

  The molar ratio can be determined by 13C-NMR. That is, the ratio of the area (3C) of the carbon atom signal derived from the carbonyl group of the isocyanurate group near 149 ppm to the area (1C) of the signal of the carbon atom derived from the urea bond near 158 ppm is measured.

(Allophanate group / (isocyanurate group + allophanate group))
The polyisocyanate composition of this embodiment further contains an allophanate group represented by the following formula (3).

  The content ratio of the allophanate group to the isocyanurate group is a molar ratio of allophanate group / (isocyanurate group + allophanate group) and is 0.2 or more and 0.9 or less. The molar ratio is preferably 0.25 or more, and more preferably 0.3 or more. The compatibility with a polyol becomes favorable because the said molar ratio is 0.2 or more. The molar ratio is preferably 0.8 or less, and more preferably 0.7 or less. Curability becomes favorable because the said molar ratio is 0.9 or less.

  The molar ratio of the allophanate group to the isocyanurate group can be determined by 1H-NMR. That is, the area of the hydrogen atom signal of the methylene group derived from HDI adjacent to the isocyanurate group near 3.85 ppm (2H), and the area of the signal of the hydrogen atom bonded to nitrogen of the allophanate bond near 8.50 ppm (1H ) To measure the ratio of isocyanurate groups to allophanate groups.

(Allophanate group / (Allophanate group + Urethane group))
In this embodiment, the content ratio between the allophanate group and the urethane group described in the following formula (4) is 0.6 to 1.0 in terms of a molar ratio of allophanate group / (allophanate group + urethane group). Preferably there is.

  The molar ratio is more preferably 0.7 or more, and further preferably 0.8 or more. When the molar ratio is 0.6 or more, the compatibility with the polyol and the curability tend to be better. The diisocyanate group and the hydroxyl group of the diol form a urethane group, and the allophanate group is formed from the isocyanate group of the diisocyanate and the urethane group. That is, the allophanate group / (allophanate group + urethane group) molar ratio is an index indicating the ratio of the structure derived from the hydroxyl group of the diol to the allophanate group. Since the molar ratio when the structure derived from the hydroxyl group of the diol is completely allophanated is 1.0, the upper limit of the molar ratio is 1.0.

  The molar ratio between the allophanate group and the urethane group can be determined by 1H-NMR. That is, the signal area (1H) of hydrogen atoms bonded to nitrogen of allophanate bonds near 8.50 ppm and the signal area (1H) of hydrogen atoms bonded to nitrogen of urethane bonds near 4.90 ppm were measured, By calculating the ratio, the molar ratio of allophanate group / (allophanate group + urethane group) is calculated.

  The number average functional group number of the polyisocyanate composition of the present embodiment is preferably 3.8 or more, more preferably 4.0 or more, still more preferably 4.2 or more, and 4.5 or more. Even more preferred. When the number average functional group number of the polyisocyanate is 3.8 or more, the curability and drying property of the coating composition tend to become better. It is preferable that the number average functional group number of the polyisocyanate composition of this embodiment is 10.0 or less, More preferably, it is 8.0 or less, More preferably, it is 6.5 or less, More preferably, it is 5.5 or less. is there. When the number average functional group number of the polyisocyanate is 10.0 or less, the coating composition tends to have a better coating film appearance. The number average functional group number can be determined based on the method described in Examples described later.

  It is preferable that the isocyanate group density | concentration of the polyisocyanate composition of this embodiment is 14.0 mass% or more, More preferably, it is 17.5 mass% or more. When the isocyanate group concentration is 14.0% by mass or more, the polyisocyanate composition tends to develop a viscosity that is easier to handle. Moreover, it is preferable that the isocyanate group density | concentration of the polyisocyanate composition of this embodiment is 21.0 mass% or less, More preferably, it is 20.0 mass% or less. When the isocyanate group concentration is 21.0% by mass or less, the curability of the coating composition tends to be better. The said isocyanate group density | concentration can be measured based on the method as described in the Example mentioned later.

  The viscosity of the polyisocyanate composition of the present embodiment measured with an E-type viscometer is preferably 8,000 to 50,000 mPa · s / 25 ° C., and preferably 8,000 to 20,000 mPa · s / 25 ° C. More preferably. In addition, although the polyisocyanate composition of this embodiment may contain a volatile component such as an aliphatic diisocyanate monomer, an alicyclic diisocyanate monomer, and a solvent, the above-mentioned viscosity is a polyisocyanate composition having a non-volatile content refined to 98% by mass or more. Can be measured in the manner described in Examples described later in more detail. When the viscosity of the polyisocyanate composition is 8,000 mPa · s / 25 ° C. or higher, the above-mentioned number average functional group number can be increased, and the curability and drying property of the coating composition tend to be better. is there. On the other hand, when the viscosity of the polyisocyanate composition is 50,000 mPa · s / 25 ° C. or less, the compatibility tends to be better.

  The concentration of the isocyanate cyclic trimer in the polyisocyanate composition of the present embodiment is preferably 30% by mass or less, and more preferably 25% by mass or less. When the said density | concentration is 30 mass% or less, it exists in the tendency for sclerosis | hardenability of a coating composition to become more favorable. The concentration of the isocyanurate cyclic trimer in the polyisocyanate composition is preferably 10% by mass or more, and more preferably 14% by mass or more. When the concentration is 10% by mass or more, the compatibility tends to be better. The concentration of the isocyanate cyclic trimer can be determined by GPC measurement. This isocyanate cyclic trimer is an isocyanurate composed of triisocyanate diisocyanate molecules.

  Next, although the example of the manufacturing method of the polyisocyanate composition of this embodiment is demonstrated, it is not limited to the following.

  First, the isocyanate group of the diisocyanate and the hydroxyl group of the diol are urethanized. The reaction temperature at this time can be set to 50 to 200 ° C. The said reaction temperature becomes like this. Preferably it is 50-150 degreeC, More preferably, it is 50-120 degreeC, More preferably, it is 50-100 degreeC. When it is 50 ° C. or higher, the urethanization reaction tends to proceed, and when it is 200 ° C. or lower, the resulting polyisocyanate composition tends to be less colored. The reaction time is preferably in the range of 0.5 hours to 24 hours, more preferably 0.5 hours to 10 hours, and even more preferably 0.5 hours to 5 hours.

  After some or all of the hydroxyl groups of the diol have reacted with the isocyanate groups of the diisocyanate, the isocyanurate and allophanate reactions are carried out. As a method for producing the polyisocyanate composition of the present embodiment, the urethanization reaction, the allophanate reaction, and the isocyanurate reaction may be performed before or after or simultaneously, but the reaction of the isocyanate group of diisocyanate and the hydroxyl group of diol. It is preferable that after forming a urethane bond, the allophanate reaction is performed simultaneously with the isocyanurate reaction. These reactions can be appropriately advanced depending on the selection of the isocyanuration reaction catalyst and the reaction conditions. When the reaction is allowed to proceed with a catalyst, the reaction temperature for isocyanurate formation and allophanate formation is 60 to 160 ° C, preferably 70 to 100 ° C. When the reaction temperature is 60 ° C. or higher, the allophanate reaction tends to proceed, and the molar ratio of allophanate group / (allophanate group + urethane group) tends to increase. When the reaction temperature is 160 ° C. or lower, the resulting polyisocyanate composition tends to be less colored. The reaction time for isocyanurate formation and allophanate formation is preferably 1 hour to 10 hours, more preferably 1 hour to 7 hours, and even more preferably 1 hour to 5 hours. When the reaction time is 1 hour or longer, the isocyanurate conversion rate and allophanate conversion rate tend to increase. When the reaction time is 10 hours or less, coloring tends to be less.

  Although it does not specifically limit as an isocyanurate formation and allophanate formation catalyst which can be used in the above, For example, what has basicity is preferable. Although not limited to the following, for example, (i) tetraalkylammonium hydroxide such as tetramethylammonium and tetraethylammonium, weak organic acid salts such as acetic acid and capric acid, (ii) trimethylhydroxypropylammonium, trimethylhydroxyethylammonium, Hydroxyalkylammonium hydroxides such as triethylhydroxypropylammonium and triethylhydroxyethylammonium, organic weak acid salts such as acetic acid and capric acid, (iii) tins of alkylcarboxylic acids such as acetic acid, caproic acid, octylic acid and myristic acid, Metal salts such as zinc and lead, (iv) metal alcoholates such as sodium and potassium, (v) aminosilyl group-containing compounds such as hexamethyldisilazane, (vi) Mannich bases, (vii) tertiary Combination with Min acids and epoxy compounds include phosphorus compounds such as (viii) tributylphosphine. Among these, tetraalkylammonium hydroxide and organic weak acid salt are preferable. These catalysts may be added all at once or continuously.

  The production method includes a step of generating a urea group in addition to the urethanization, isocyanurate formation, and allophanate reaction steps. The method for generating the urea group is not particularly limited. For example, a method in which the diisocyanate is heated in the presence of water or an amine compound having two or more functional groups is added and heated to react with the diisocyanate. The former method is preferable from the viewpoint of production stability. The amount of water used to generate the urea group is preferably 1 ppm or more and 10,000 ppm or less, more preferably 5 ppm or more and 5000 ppm or less, and still more preferably 10 ppm or more and 2000 ppm or less with respect to the diisocyanate as a raw material. Examples of the method of adding water include adding directly to the diisocyanate or adding the diol containing water. The heating temperature for generating the urea group is preferably in the same range as the urethanization reaction, isocyanurate reaction, and allophanate reaction.

  In order to terminate these reactions, the catalyst may be deactivated. When neutralizing and deactivating the catalyst, for example, an acidic substance such as phosphoric acid or acidic phosphate is added. It can also be deactivated by thermal decomposition or chemical decomposition. Further, it can be deactivated by adsorbing it on activated carbon, alumina or the like and taking it out of the system.

  The yield of the polyisocyanate composition (mass of the obtained polyisocyanate composition / total mass of the charged raw materials × 100) is preferably selected from the range of 10 to 70% by mass, more preferably 30 to 60% by mass. By doing it, the molar ratio of the isocyanate group with respect to an allophanate group and a urethane group can be made high, and the molar ratio of the isocyanate group with respect to an allophanate group and a urethane group can be made low by making low.

  After completion of the reaction, unreacted diisocyanate monomer is removed by a thin film evaporator, extraction or the like. The unreacted diisocyanate monomer concentration in the obtained polyisocyanate composition is preferably 3% by mass or less, more preferably 1% by mass or less, still more preferably 0.5% by mass or less, and still more preferably. Is 0.3 mass% or less. When the unreacted diisocyanate monomer concentration is 3% by mass or less, the curability tends to be better.

[Coating composition]
Next, the coating composition containing the polyisocyanate composition of this embodiment is described. That is, the coating composition of this embodiment contains the polyisocyanate composition of this embodiment and at least one kind of polyol. For example, the coating composition of this embodiment is constituted by mixing the polyisocyanate composition obtained as described above with a compound containing two or more active hydrogens having reactivity with isocyanate groups in the molecule. Can do. These components can react with each other to form a crosslinked coating.

  Although it does not limit to the following as a compound which contains two or more of said active hydrogen in a molecule | numerator, For example, a polyol, a polyamine, a polythiol etc. can be mentioned, Two or more types can be used together. A polyol is preferred. Examples of this polyol include, but are not limited to, acrylic polyols, polyester polyols, polyether polyols, polyolefin polyols, epoxy polyols, and fluorine-based polyols. Among these polyols, acrylic polyols and polyesters are preferable. Polyols and polyether polyols.

  Examples of acrylic polyols include, but are not limited to, acrylic esters having active hydrogen such as 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, and 2-hydroxybutyl acrylate, or acrylic glycerin. An acid monoester or a methacrylic acid monoester, a trimethylolpropane acrylic acid monoester or a methacrylic acid monoester alone or in a mixture thereof; methyl acrylate, ethyl acrylate, isopropyl acrylate, acrylic acid-n- Acrylic acid esters such as butyl, 2-ethylhexyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-hydroxybutyl methacrylate, -3-hydroxypropyl methacrylate , Methacrylates with active hydrogen such as 4-hydroxybutyl methacrylate, or methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, -n-butyl methacrylate, isobutyl methacrylate, n-hexyl methacrylate, methacryl A single or a mixture selected from the group of methacrylic acid esters such as lauryl acid; unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, itaconic acid, acrylamide, N-methylol acrylamide, diacetone acrylamide, etc. In the presence or absence of a saturated amide and a single or mixture selected from the group of other polymerizable monomers such as glycidyl methacrylate, styrene, vinyl toluene, vinyl acetate, acrylonitrile, dibutyl fumarate; And the like obtained acrylic polyol.

  Examples of the polyester polyol include, but are not limited to, dibasic acid selected from the group of carboxylic acids such as succinic acid, adipic acid, sebacic acid, dimer acid, maleic anhydride, phthalic anhydride, isophthalic acid, and terephthalic acid. A polyester polyol obtained by a condensation reaction of an acid alone or a mixture thereof; and a polyhydric alcohol alone or a mixture selected from the group of ethylene glycol, propylene glycol, diethylene glycol, neopentyl glycol, trimethylolpropane, glycerin and the like; Can be mentioned. These polyester polyols can be modified with aromatic diisocyanates, aliphatic diisocyanates, alicyclic diisocyanates and polyisocyanates obtained therefrom. In this case, in particular, aliphatic diisocyanate, alicyclic diisocyanate, and polyester polyol modified with polyisocyanate obtained therefrom are preferable from the viewpoint of weather resistance, yellowing resistance and the like.

  Examples of the polyether polyol include, but are not limited to, for example, a single or mixture of polyols having a molecular weight of 500 or less, a hydroxide such as lithium, sodium, and potassium, an alcoholate, a strongly basic catalyst such as an alkylamine, and a metal porphyrin. Random or block addition of alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, cyclohexene oxide, styrene oxide, alone or as a mixture using a complex metal cyanide complex such as zinc hexacyanocobaltate complex A polyether polyol obtained by reacting an alkylene oxide with a polyamine compound such as ethylenediamine, and a polyether polyol obtained by Obtained by polymerizing acrylamide or the like as the body, it includes so-called polymer polyols.

  Examples of the polyolefin polyol include, but are not limited to, polybutadiene having two or more hydroxyl groups, hydrogenated polybutadiene, polyisoprene, hydrogenated polyisoprene, and the like.

  Examples of the epoxy polyol include, but are not limited to, novolak type, β-methyl epichloro type, cyclic oxirane type, glycidyl ether type, glycol ether type, aliphatic unsaturated compound epoxy type, epoxidized fatty acid ester type, polyvalent type Examples thereof include carboxylic acid ester type, aminoglycidyl type, halogenated type, resorcin type and the like, and compounds obtained by modifying them with amino compounds, polyamide compounds and the like.

  The fluorine-based polyol is a polyol containing fluorine in the molecule, and is not limited to the following. For example, fluoroolefins, cyclohexyl vinyl ethers, hydroxyalkyl vinyl ethers disclosed in US Pat. No. 4,345,057, EP 180962, etc. And copolymers such as monocarboxylic acid vinyl ester.

  In this embodiment, it is preferable that the hydroxyl value of the polyol used as a component of the coating composition is 30 to 200 mgKOH / g. Moreover, it is preferable that the acid value of the said polyol is 0-30 mgKOH / g. Two or more of these polyols may be used in combination. Among them, the hydroxyl value of the polyol used is preferably 70 to 165 mgKOH / g and the acid value is preferably 2 to 20 mgKOH / g.

  When preparing a coating composition using the polyisocyanate composition of this embodiment, the equivalent ratio of the isocyanate group of the polyisocyanate composition and the hydroxyl group of the polyol is appropriately selected from the range of 1/2 to 2/1. It is preferable.

  Depending on the application and purpose of the coating composition, various solvents, UV absorbers such as benzotriazole and benzophenone, light stabilizers such as hindered amine and hindered phenol, organic pigments such as quinacridone, pigment red and phthalocyanine blue, titanium oxide Inorganic pigments such as carbon black, metallic pigments such as aluminum powder, optical interference pigments such as pearl mica powder, curing accelerators such as tin compounds, zinc compounds, and amine compounds can be blended. Examples of the solvent include, but are not limited to, ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, esters such as ethyl acetate, n-butyl acetate, and cellosolve acetate, alcohols such as butanol and isopropyl alcohol, and the like. It can be used by appropriately selecting from the group according to the purpose and application. These solvents may be used alone or in combination of two or more.

  The coating composition prepared in this manner can be applied by methods such as roll coating, curtain flow coating, and spray coating, and is usually applied with a dry film thickness of about 10 to 100 μm. It is particularly useful in fields such as automotive repair paints and plastic paints. Moreover, the coating composition of this embodiment can also be used for a clear coat.

[Manufacturing method of coated body]
The manufacturing method of the coated body of this embodiment includes the process of coating the coating composition of this embodiment on a base material. Here, the base material can be a base coat containing a pigment, and the above-mentioned organic pigment, inorganic pigment, metallic pigment, optical interference pigment and the like can be appropriately used as the pigment.

  Hereinafter, the present embodiment will be described in more detail based on examples, but the present embodiment is not limited to the following examples. All parts are parts by mass.

  First, a method for measuring each physical property will be described.

(Number average molecular weight)
The number average molecular weight of the polyisocyanate composition is a polystyrene-based number average molecular weight measured by gel permeation chromatography (hereinafter referred to as GPC) using the following apparatus.
Equipment: HLC-8120 (manufactured by Tosoh Corporation),
Columns used: TSK GEL SuperH1000, TSK GEL SuperH2000, TSK GEL SuperH3000 (all manufactured by Tosoh Corporation),
Sample concentration: 5 wt / vol%
Carrier: THF,
Detection method: parallax refractometer,
Outflow amount: 0.6 mL / min,
Column temperature: 30 ° C.

  GPC calibration curves are polystyrene (molecular weight 50000-2050 PSS-06 (Mw 50000), BK 13007 (Mp = 20000, Mw / Mn = 1.03), PSS-08 (Mw = 9000), PSS. -09 (Mw = 4000) and 5040-35125 (Mp = 2050, Mw / Mn = 1.05)) and isocyanates of hexamethylene diisocyanate polyisocyanate composition (Duranate TPA-100, manufactured by Asahi Kasei Chemicals Corporation) Nurate group trimer to 7mer (isocyanurate trimer molecular weight = 504, isocyanurate pentamer molecular weight = 840, isocyanurate heptamer molecular weight = 1176) and HDI (molecular weight = 168) were prepared as standards. .

(yield)
The yield was calculated from the following formula.
Yield (%) = mass of obtained polyisocyanate composition / total mass of charged raw materials × 100

(Number average functional group)
The number average functional group number of the polyisocyanate composition was calculated from the following formula based on the number average molecular weight of the polyisocyanate composition measured as described above and the value of the isocyanate group concentration measured by the method described later.
Number average functional group number of polyisocyanate composition = number average molecular weight of polyisocyanate composition × isocyanate group concentration / 42

(Isocyanate group concentration)
N-dibutylamine was added to the polyisocyanate composition dissolved in toluene, and the isocyanate group concentration in the polyisocyanate composition was determined by potentiometric titration using 1N hydrochloric acid.
The non-volatile content of the polyisocyanate composition produced in each of Examples and Comparative Examples described later was examined by the method described below, and the value of 98% by mass or more was used for the measurement of the isocyanate group concentration. did.

(Measurement of non-volatile content)
The nonvolatile content was determined from the remaining amount when the polyisocyanate composition was heated at 105 ° C. for 3 hours.
Nonvolatile content (mass%) = (mass of polyisocyanate composition after heating at 105 ° C. for 3 hours) / (mass of polyisocyanate composition before heating) × 100

(Measurement of viscosity)
The viscosity of the polyisocyanate composition was measured using an E-type viscometer (RE-80U from Toki Sangyo Co., Ltd.) at a cone plate of 3 degrees R12 and 25 ° C. (unit: mPa · s / 25 ° C.).
In addition, the non volatile matter of the polyisocyanate composition manufactured by each Example and each comparative example which are mentioned later was investigated by the method as described above, and the value of 98% by mass or more was used for the measurement of the viscosity.

(Diisocyanate monomer concentration)
The peak area% corresponding to the molecular weight of the diisocyanate obtained by the GPC measurement (for example, 168 for HDI) was expressed as the mass concentration of the diisocyanate monomer in the polyisocyanate composition.

(Qualitative or quantitative determination of urea and isocyanurate groups)
Using a FT-NMR AVANCE600 manufactured by Bruker, 13C nuclear magnetic resonance spectrum was measured at a sample (polyisocyanate composition) concentration of 60% by mass, 600 MHz, and 10,000 times of accumulation using deuterated chloroform CDCl ₃ as a solvent. And the molar ratio of isocyanurate groups.
Molar ratio 1: urea group / (urea group + isocyanurate group) = (signal area around 158 ppm) / (signal area around 158 ppm + signal area around 149 ppm / 3)

(Qualitative or quantitative determination of allophanate group, isocyanurate group and urethane group)
Using a FT-NMR AVANCE 600 manufactured by Bruker, proton nuclear magnetic resonance spectrum was measured at a sample (polyisocyanate composition) concentration of 5% by mass, 600 MHz, and 256 times of accumulation using deuterated chloroform CDCl ₃ as a solvent. The molar ratio of the isocyanurate group and the urethane group was confirmed. Based on the total protons at β-position and γ-position derived from HDI, the isocyanurate group is the area ratio of the hydrogen atom signal of the methylene group adjacent to the isocyanurate group near 3.85 ppm, and the allophanate group is 8.50 ppm. Measure the area ratio of the hydrogen atom signal bonded to nitrogen in the nearby allophanate bond, the urethane group measured the area ratio of the hydrogen atom signal bonded to nitrogen in the urethane bond near 4.90 ppm, and use the following formula to determine the molar ratio 2 and 3 were obtained.
Molar ratio 2: Allophanate group / (Allophanate group + isocyanurate group) = (Signal area around 8.50 ppm) / (Signal area around 8.50 ppm + Signal area around 3.85 ppm / 6)
Molar ratio 3: allophanate group / (allophanate group + urethane group) = (signal area around 8.50 ppm) / (signal area around 8.50 ppm + signal area around 4.90 ppm)

(Curable)
After coating the coating composition on a PP plate, a coating film cured at 23 ° C./50% RH for 24 hours and a coating film cured for 48 hours were immersed in about 40 g of acetone at 20 ° C. for 24 hours. Then, the value with respect to the mass before immersion of undissolved part mass was computed, and the obtained value was made into the sclerosis | hardenability parameter | index.

(Drying experiment)
The coating composition was applied on a glass plate to a film thickness of 40 μm and then cured at 23 ° C./50% RH. After the elapse of 5 hours and 7 hours, a cotton ball (cylindrical shape having a diameter of 2.5 cm and a height of 2.0 cm) was placed on the coating film, and a 100 g weight was placed thereon for 60 seconds. Thereafter, the weight and cotton were removed, and the cotton marks remaining on the coating film were observed. The case where the trace was not visible at all was expressed as 1 and the case where the trace was clearly visible was expressed as 5 levels from 1 to 5.

(Appearance of coating film)
Using a general-purpose three-dimensional surface structure analyzer (NewView 600 of Canon Inc.), the coating composition was applied on the electrodeposition plate to a film thickness of 40 μm at room temperature, and then at 23 ° C./50% RH for one day. After curing, the coating surface was measured. The case where the amplitude of the unevenness on the coating film surface is 50 nm or less is 3, 3 is 50 to 70 nm, 1 is 70 nm or more, and 1 to 3 are shown. The larger the value, the better the appearance of the coating film.

(Compatibility)
Each of the polyol and the polyisocyanate composition was blended at an isocyanate group / hydroxyl group equivalent ratio of 1.0, and adjusted to have a solid content of 50% with butyl acetate, and then evaluated on the appearance of the diluted solution. Judgment was made based on whether or not it was transparent. As the polyol, Lumiflon (registered trademark) LF-200 (resin concentration 60%, hydroxyl value 53.3 mgKOH / resin g) manufactured by Asahi Glass Co., Ltd., which is a fluorine-based polyol, and ACRICID (registered trademark) manufactured by DIC, which is an acrylic polyol A-801-P (resin content concentration 50%, hydroxyl value 50.0 mgKOH / resin g) was used for evaluation.

(Moisture stability)
A solution was prepared by mixing 5.0 g of the polyisocyanate composition and 5.0 g of ethyl acetate. And the storage time until the solution preserve | saved on 23 degreeC and saturation humidity conditions will be in a gel state was measured, and moisture stability was evaluated based on the following references | standards. The gel state referred to here is a state in which the liquid level does not move when 10 seconds have passed after putting the solution in the sample bottle and laying the sample bottle sideways.
◯: When the storage time until the gel state is 72 hours or more Δ: When the storage time until the gel state is 48 hours or more and less than 72 hours ×: Storage time until the gel state is reached When it is less than 48 hours

Example 1
A four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen blowing tube is placed in a nitrogen atmosphere, 600 parts of HDI, 10.8 parts of 1,3-butanediol which is a dihydric alcohol, and 0.24 of water. (400 ppm with respect to HDI) was added, and the temperature in the reactor was kept at 90 ° C. for 1 hour with stirring to conduct a urethanization reaction. Thereafter, the temperature in the reactor was kept at 80 ° C., 0.03 part of tetramethylammonium capriate was added as an isocyanuration catalyst, the refractive index of the reaction solution was measured, and when the yield reached 55%, phosphoric acid Was added to stop the reaction. After the reaction solution was filtered, unreacted HDI was removed using a thin film evaporator. The non-volatile content of the obtained 343 g of the polyisocyanate composition was 99.8% by mass, the viscosity at 25 ° C. was 20,800 mPa · s, the isocyanate group concentration was 19.2% by mass, the diisocyanate monomer concentration was 0.15% by mass, The number average molecular weight was 970, and the number average functional group number was 4.4. The molar ratio of (allophanate group / (allophanate group + urethane group)) was 0.99. Table 1 shows the composition of the raw materials used, the reaction conditions, and the physical properties of the prepared polyisocyanate composition.

(Example 2)
A four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen blowing tube is placed in a nitrogen atmosphere, 600 parts of HDI, 24 parts of 1,3-butanediol, which is a dihydric alcohol, and 0.24 parts of water. (400 ppm with respect to HDI) was added, and the temperature in the reactor was kept at 90 ° C. for 1 hour with stirring to conduct a urethanization reaction. Thereafter, the temperature in the reactor was kept at 80 ° C., 0.03 part of tetramethylammonium capriate was added as an isocyanuration catalyst, the refractive index of the reaction solution was measured, and when the yield reached 55%, phosphoric acid Was added to stop the reaction. After the reaction solution was filtered, unreacted HDI was removed using a thin film evaporator. The obtained 343 g of the polyisocyanate composition had a nonvolatile content of 99.8% by mass, a viscosity at 25 ° C. of 14,500 mPa · s, an isocyanate group concentration of 19.0% by mass, a diisocyanate monomer concentration of 0.09% by mass, The number average molecular weight was 1040, and the number average functional group number was 4.6. The molar ratio of (allophanate group / (allophanate group + urethane group)) was 0.98. Table 1 shows the composition of the raw materials used, the reaction conditions, and the physical properties of the prepared polyisocyanate composition.

(Examples 3 to 5)
The synthesis was performed in the same manner as in Example 1 except that the composition of the raw materials and the reaction conditions were changed as shown in Table 1. Table 1 shows the composition and reaction conditions of these raw materials and the physical properties of the polyisocyanate composition.

  Table 2 shows the results of compatibility evaluation and moisture stability of the polyisocyanate compositions obtained in Examples 1 to 5.

(Examples 6 to 10)
Acrylic polyol (Nuplex trade name “SETALUX1753”, resin concentration 70%, hydroxyl value 138.6 mg KOH / g) and each of the polyisocyanate compositions obtained in Examples 1-7 were After blending at an equivalent ratio of 1.0 and appropriately adjusting the viscosity of the paint with an organic solvent, the coating film was evaluated. Table 2 shows the physical properties of the curing agent and the coating film used.

(Comparative Examples 1-6)
The synthesis was performed in the same manner as in Example 1 except that the composition of the raw materials and the reaction conditions were changed as shown in Table 1. Table 1 shows the composition and reaction conditions of these raw materials and the physical properties of the polyisocyanate composition.

(Comparative Examples 7-12)
Evaluation was performed in the same manner as in Example 6 except that the curing agent shown in Table 2 was used. Table 2 shows the physical properties of the curing agent and the coating film used.

  The coating composition of the present invention is useful in a wide range of fields such as automobile repair coatings and plastic coatings. In particular, drying property at low temperature and curability are beneficial. Further, a clear paint containing no pigment is also useful as a paint excellent in acid rain resistance and weather resistance.

Claims (7)

A polyisocyanate composition obtained from one or more diisocyanates and one or more diols selected from aliphatic diisocyanates and alicyclic diisocyanates,
In the polyisocyanate composition, the molar ratio of urea group / (urea group + isocyanurate group) is 0.0001 to 0.1, and the molar ratio of allophanate group / (isocyanurate group + allophanate group) is 0.00. A polyisocyanate composition which is 2 to 0.9.   The polyisocyanate composition according to claim 1, wherein the molar ratio of allophanate group / (allophanate group + urethane group) is 0.6 to 1.0.   The polyisocyanate composition according to claim 1 or 2, wherein the number average functional group number is 3.8 to 10.0.   The polyisocyanate composition according to any one of claims 1 to 3, wherein the isocyanate group concentration is 14.0 to 21.0 mass%.   The polyisocyanate composition as described in any one of Claims 1-4 whose viscosity in 25 degreeC is 8,000-50,000 mPa * s.   The coating composition containing the polyisocyanate composition as described in any one of Claims 1-5, and at least 1 type of polyol.   The manufacturing method of a coating body including the process of apply | coating the coating composition of Claim 6 on a base material.