JP2018028019A - Polyisocyanate composition, aqueous coating composition, and cured coating film thereof - Google Patents

Abstract

Disclosed is a polyisocyanate composition having low viscosity, storage stability and moisture stability, and good mixing stability with a main agent when used as an aqueous paint. The uretonimino group / the isocyanurate group is obtained from an aliphatic diisocyanate containing 1,6-diisocyanatohexane and contains an isocyanurate group, a uretdione group, a uretonimino group, and an iminooxadiazinedione group. The molar ratio of the iminooxadiazinedione group / isocyanurate group is 0.00050-0.30, and the phosphorus concentration in plasma emission spectrometry is A polyisocyanate composition which is 1 to 50 ppm. [Selection figure] None

Description

  The present invention relates to a polyisocyanate composition, an aqueous coating composition and a cured coating film thereof.

A two-component curable resin composed of a hydroxyl group-containing main component (so-called polyol) and a polyisocyanate as a curing agent can be cured at room temperature, and has excellent mechanical performance, chemical resistance, durability, and the like. Therefore, it is widely used in various applications such as paints and adhesives.
In recent years, water-based development has been actively developed among two-component curable resins from the viewpoints of global environmental protection and occupational safety and health. For example, as described in Patent Document 1, there is one in which a polyisocyanate composition is provided with a compounding property to an aqueous main agent by containing a hydrophilic component. For example, as described in Patent Documents 2 and 3, there are those imparting a compounding property to an aqueous main agent by having a curing agent having a specific structure and a specific viscosity.

Japanese Patent No. 3491919 JP 2013-245341 A Japanese Patent Laid-Open No. 2006-53127

By using the technique described in Patent Document 1, an isocyanate composition containing a hydrophilic component can be used as an aqueous coating composition, but the polyisocyanate composition obtained by this technique Has a problem that water resistance decreases due to the inclusion of a hydrophilic group. By using the techniques described in Patent Documents 2 and 3, it is possible to obtain a low-viscosity polyisocyanate and use it in an aqueous coating composition. However, the polyisocyanate composition obtained by this technique has a problem that the mixing stability with the main agent is insufficient when used in an aqueous paint.
Therefore, an object of the present invention is to provide a polyisocyanate composition that has low viscosity, has storage stability and moisture stability, and has good mixing stability with the main agent when used as an aqueous paint. .

As a result of intensive studies by the present inventors, it is obtained from an aliphatic diisocyanate containing at least 1,6-diisocyanatohexane (HDI), and isocyanurate group, uretdione group, uretonimino group, and iminooxadiazinedione group. A polyisocyanate composition in which the molar ratio of the uretonimino group to the isocyanurate group and the iminooxadiazinedione group to the isocyanurate group is in a specific range, and the phosphorus concentration is in a specific range, It has been found that it has a low viscosity, is excellent in storage stability and moisture stability, and is excellent in stability when blended with a main ingredient of a water-based paint, thereby completing the present invention.
That is, the present invention is as follows.

[1]
Obtained from an aliphatic diisocyanate containing 1,6-diisocyanatohexane,
Containing an isocyanurate group, a uretdione group, a uretonimino group, and an iminooxadiazinedione group;
The molar ratio of the uretonimino group / the isocyanurate group is 0.0010 to 0.0050, the molar ratio of the iminooxadiazinedione group / the isocyanurate group is 0.00050 to 0.30, and
The phosphorus concentration in plasma emission spectroscopy is 1-50 ppm,
Polyisocyanate composition.
[2]
An aqueous coating composition comprising an aqueous acrylic polyol, a surface tension adjusting agent, and the polyisocyanate composition according to [1].
[3]
The coating film which hardened the water-based coating composition as described in [2].

  According to the present invention, it is possible to provide a polyisocyanate composition having a low viscosity, excellent storage stability and moisture stability, and excellent mixing stability with the main agent.

  Hereinafter, a mode for carrying out the present invention (hereinafter simply referred to as “the present embodiment”) will be described in detail. The following embodiments are examples for explaining the present invention, and are not intended to limit the present invention to the following contents. The present invention can be implemented with appropriate modifications within the scope of the gist thereof. Unless otherwise specified, “(meth) acryl” includes methacryl and acryl, and “(meth) acrylate” includes methacrylate and acrylate.

[Polyisocyanate composition]
The polyisocyanate composition of the present embodiment is obtained from an aliphatic diisocyanate containing at least 1,6-diisocyanatohexane (hereinafter also referred to as HDI), and isocyanurate group, uretdione group, uretonimino group, and iminooxa Contains a diazinedione group.
Further, the molar ratios of the uretonimino group / the isocyanurate group and the iminooxadiazinedione group / the isocyanurate group are within a specific range as follows. That is, in the polyisocyanate composition of the present embodiment, the molar ratio of uretonimino group / isocyanurate group is 0.0010 to 0.0050, and the molar ratio of iminooxadiazinedione group / isocyanurate group is 0.00050. ~ 0.30.
Furthermore, the polyisocyanate composition of the present embodiment has a phosphorus concentration in the plasma emission spectroscopic analysis of 1 to 50 ppm.
Since the polyisocyanate composition of the present embodiment has the above-described configuration, it has a low viscosity, is excellent in storage stability and moisture stability, is excellent in stability when blended with a main ingredient of an aqueous paint, and A coating film excellent in image clarity can be formed.

(Aliphatic diisocyanate)
The aliphatic diisocyanate in this embodiment contains at least HDI. From the viewpoint of industrial availability and reactivity during production of the polyisocyanate, the polyisocyanate composition of the present embodiment is a polyisocyanate composition obtained from an aliphatic diisocyanate containing HDI.
The aliphatic diisocyanate is not limited to the following in addition to HDI, but may include, for example, those having 4 to 30 carbon atoms (excluding HDI). Specific examples include 1,4-diisocyanatobutane, 1,5-diisocyanatopentane, 2,2,4-trimethyl-1,6-diisocyanatohexane, and lysine diisocyanate.

  The polyisocyanate composition of this embodiment may include a part of units derived from alicyclic diisocyanate. The alicyclic diisocyanate is not limited to the following, but for example, those having 8 to 30 carbon atoms are preferable. Specifically, isophorone diisocyanate (hereinafter referred to as IPDI), 1,3- Bis (isocyanatemethyl) -cyclohexane, 4,4′-dicyclohexylmethane diisocyanate, norbornene diisocyanate, hydrogenated xylylene diisocyanate, and the like. Of these, IPDI is preferred as the alicyclic diisocyanate from the viewpoint of weather resistance and industrial availability. Only one type of alicyclic diisocyanate may be used alone, or two or more types may be used in combination.

  The polyisocyanate composition of this embodiment contains an isocyanurate group. The isocyanurate group, which is one of the constituent components of the polyisocyanate composition of the present embodiment, is a functional group derived from polyisocyanate consisting of three molecules of diisocyanate (hereinafter also referred to as “diisocyanate monomer”). (II) (hereinafter, the isocyanurate group is also referred to as “isocyanurate trimer”).

  The concentration of the isocyanurate trimer in the polyisocyanate composition of the present embodiment is not particularly limited, but is preferably 55 to 95 mass% with respect to the total amount of the polyisocyanate composition, and is 60 to 95 mass%. More preferably. From the viewpoint of reducing the viscosity of the polyisocyanate composition of the present embodiment, the concentration is preferably 55% by mass or more, and from the viewpoint of keeping the yield of the polyisocyanate composition high, it is 95% by mass or less. preferable. The concentration of the isocyanurate trimer can be measured by gel permeation chromatography (hereinafter sometimes referred to as “GPC”).

  The polyisocyanate composition of this embodiment contains a uretdione group. By containing the uretdione group, the viscosity of the polyisocyanate composition can be reduced. The uretdione group, which is one of the components of the polyisocyanate composition of the present embodiment, is a polyisocyanate-derived functional group composed of two molecules of a diisocyanate monomer, and is represented by the following formula (III).

In the polyisocyanate composition of the present embodiment, the molar ratio of uretdione group / isocyanurate group is not particularly limited, but is preferably 0.010 to 0.50. The lower limit value of the molar ratio is more preferably 0.15, still more preferably 0.20, and still more preferably 0.30. The upper limit of the molar ratio is more preferably 0.45, still more preferably 0.40, and still more preferably 0.38. From the viewpoint of reducing the viscosity of the polyisocyanate composition of the present embodiment, the molar ratio is preferably 0.010 or more, and preferably 0.50 or more from the viewpoint of improving crosslinkability. The molar ratio of uretdione group / isocyanurate group can be determined by measurement of ¹³ C-NMR. Specifically, it can measure according to the method as described in the Example mentioned later.

  As a method for controlling the molar ratio of uretdione group / isocyanurate group to a range of 0.010 to 0.50, for example, an isocyanurate reaction of an aliphatic diisocyanate containing 1,6-diisocyanatohexane was performed. Thereafter, the catalyst is deactivated, and then controlled by reacting at a temperature of about 140 to 160 ° C., preferably 145 to 165 ° C. for about several hours, preferably 1 to 3 hours, A polyisocyanate composition obtained by carrying out an isocyanurate reaction of an aliphatic diisocyanate containing diisocyanatohexane, and an uretdione such as a tertiary phosphine with respect to an aliphatic diisocyanate containing 1,6-diisocyanatohexane. The catalyst was added and reacted at a temperature of about 20 to 80 ° C. for several hours to several tens of hours. And a method to be partially mixed with the polyisocyanate composition. Among the above methods, from the viewpoint of availability, the former isocyanurate-forming reaction of an aliphatic diisocyanate containing 1,6-diisocyanatohexane was performed, the catalyst was deactivated, and then 145 to 165 ° C. A method of reacting at a temperature of about several hours is preferable.

  The polyisocyanate composition of this embodiment contains a uretonimino group. The uretonimino group, which is one of the components of the polyisocyanate composition of the present embodiment, is a polyisocyanate-derived functional group composed of three molecules of a diisocyanate monomer, and is represented by the following formula (IV).

  The molar ratio of uretonimino group / isocyanurate group is 0.0010 to 0.0050. The lower limit of the molar ratio is preferably 0.0012, more preferably 0.0015, and still more preferably 0.0020. The upper limit of the molar ratio is preferably 0.0045, more preferably 0.0040, and still more preferably 0.0035. When the molar ratio is 0.0010 or more, the moisture stability of the polyisocyanate composition of the present embodiment is good, and when it is 0.0050 or less, an increase in the diisocyanate monomer concentration after storage is suppressed. Can do. The molar ratio of uretonimino group / isocyanurate group can be measured by the method described in Examples described later.

  As a method for controlling the molar ratio of uretonimino group / isocyanurate group to a range of 0.0010 to 0.0050, for example, an isocyanurate reaction of an aliphatic diisocyanate containing 1,6-diisocyanatohexane was performed. Thereafter, the catalyst was deactivated, and then controlled by reacting at a temperature of about 140 to 160 ° C., preferably 145 to 155 ° C. for about several hours, preferably 1 to 3 hours. For polyisocyanate composition, aliphatic diisocyanate containing 1,6-diisocyanatohexane and a phosphorus-containing phosphorus compound such as 1-butylphosphorane as a catalyst at a temperature of about 20 to 80 ° C. for several hours And a method of partially mixing the reacted polyisocyanate composition for about several tens of hours. Among the above methods, from the viewpoint of availability, the former isocyanurate-forming reaction of aliphatic diisocyanate containing 1,6-diisocyanatohexane was performed, and then the catalyst was deactivated, and then 140 to 160 ° C. A method of reacting at a temperature of about several hours is preferable.

  The polyisocyanate composition of this embodiment contains an iminooxadiazinedione group. The iminooxadiazinedione group, which is one of the components of the polyisocyanate composition of the present embodiment, is a polyisocyanate-derived functional group composed of three diisocyanate monomers, and is represented by the following formula (V). Is.

  The molar ratio of iminooxadiazinedione group / isocyanurate group in the polyisocyanate composition of the present embodiment is 0.00050 to 0.30. The lower limit of the molar ratio is preferably 0.0010, more preferably 0.0015, still more preferably 0.0020, and still more preferably 0.0025. The upper limit of the molar ratio is preferably 0.20, more preferably 0.10, still more preferably 0.050, and even more preferably 0.025. When the molar ratio is 0.00050 or more, moisture stability of the polyisocyanate composition of the present embodiment can be expressed, and when the molar ratio is 0.30 or less, a coating film having excellent image clarity is obtained. It becomes a polyisocyanate composition that can be formed. The molar ratio of iminooxadiazinedione group / isocyanurate group can be measured by the method described in Examples described later.

  As a method of controlling the molar ratio of iminooxadiazinedione group / isocyanurate group within the above range, for example, after carrying out the isocyanuration reaction of aliphatic diisocyanate containing 1,6-diisocyanatohexane, the catalyst is used. A method of controlling by deactivation and then reacting at a temperature of about 140 to 160 ° C. for about several hours, or an aliphatic containing 1,6-diisocyanatohexane in the polyisocyanate composition obtained above. The diisocyanate is partially mixed with a polyisocyanate composition reacted for several hours to several tens of hours at a temperature of about 20 to 80 ° C. using a phosphorus-containing phosphorus compound such as 1-butylphosphorane as a catalyst. Method. Among the above, from the viewpoint of easy availability, after the former isocyanurate-forming reaction of aliphatic diisocyanate containing 1,6-diisocyanatohexane, the catalyst is deactivated, and thereafter 140 to 160 ° C. A method of reacting at a temperature of about several hours is preferable.

  The polyisocyanate composition of this embodiment preferably further contains an isocyanurate / uretdione-bonded tetramer represented by the following formula (I). The isocyanurate / uretdione bond tetramer is a polyisocyanate-derived tetramolecular structure composed of four diisocyanate monomers and is represented by the following formula (I).

  In the polyisocyanate composition of the present embodiment, the abundance ratio of isocyanurate / uretdione-bonded tetramer / isocyanurate trimer is not particularly limited, but is 0.010 as an area ratio in liquid chromatography. It is preferably ˜0.10. The lower limit value of the area ratio is more preferably 0.020, still more preferably 0.030, and still more preferably 0.050. The upper limit of the area ratio is preferably 0.090, more preferably 0.085, and even more preferably 0.080. When the area ratio is 0.010 or more, the image clarity of the coating film using the polyisocyanate composition tends to be better, and when the area ratio is 0.10 or less, There is a tendency that the increase in the diisocyanate monomer can be further reduced. The abundance ratio of isocyanurate / uretdione-bonded tetramer / isocyanurate trimer can be measured by the method described in the examples described later.

  As a method for controlling the isocyanurate / uretdione-bonded tetramer / isocyanurate trimer abundance ratio, that is, the area ratio in liquid chromatography within the above range, for example, an aliphatic containing 1,6-diisocyanatohexane After carrying out the isocyanurate-forming reaction of diisocyanate, the catalyst is deactivated, and then the reaction is carried out at a temperature of about 140 to 170 ° C. for about several hours.

  Moreover, the polyisocyanate composition of this embodiment may contain an allophanate group. An allophanate group is formed by reacting a hydroxyl group of alcohol with an isocyanate group in an aliphatic diisocyanate, and is represented by the following formula (VI).

  The alcohol that can be used to form the allophanate group is preferably an alcohol formed only of carbon, hydrogen and oxygen, and more preferably a monoalcohol. A monoalcohol having a molecular weight of 200 or less is more preferable. Examples of the alcohol include, but are not limited to, monoalcohols such as methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol, octanol, and nonanol; ethylene glycol, 1,3-butanediol, And dialcohols such as neopentyl glycol and 2-ethylhexanediol. These may be used alone or in combination of two or more.

  The molar ratio of allophanate group / isocyanurate group derived from alcohol is preferably 0.010 to 0.20, more preferably 0.010 to 0.10, and still more preferably 0.010 to 0.05. is there. From the viewpoint of improving the crosslinkability, it is preferably 0.20 or less. The molar ratio of allophanate group / isocyanurate group can be measured by the method described in Examples described later.

  In addition to the above, the polyisocyanate composition of the present embodiment may contain a urethane group, a urea group, a burette group, a carbodiimide group, and the like.

  The phosphorus concentration in the polyisocyanate composition of this embodiment is 1 ppm to 50 ppm. The lower limit of the phosphorus concentration is preferably 2 ppm or more. The upper limit of the phosphorus concentration is preferably 45 ppm, more preferably 40 ppm, and even more preferably 35 ppm. By setting the upper limit of the phosphorus concentration to 50 ppm, the mixing stability with the main component of the polyisocyanate composition of this embodiment can be improved. By setting the lower limit of the phosphorus concentration to 1 ppm, the storage stability of the polyisocyanate composition can be improved. The phosphorus concentration of the polyisocyanate composition of the present embodiment is a concentration measured by plasma emission spectroscopic analysis, and can be specifically measured by a method described later. Moreover, the phosphorus concentration of the polyisocyanate composition can be adjusted by adjusting the amount of phosphorus compound added during the production of the polyisocyanate described later, filtration conditions, and the like.

  The diisocyanate monomer concentration in the polyisocyanate composition of the present embodiment is preferably 1.0% by mass or less, more preferably 0.5% by mass or less, still more preferably 0.3% by mass or less, More preferably, it is 0.2 mass% or less. From the viewpoint of improving the crosslinkability, it is preferably 1.0% by mass or less. The diisocyanate monomer concentration in the polyisocyanate composition of the present embodiment can be measured by a method according to the measurement of the HDI monomer mass concentration described later.

  Although the viscosity in 25 degreeC of the polyisocyanate composition of this embodiment is not specifically limited, It is preferable that it is 100-1500 mPa * s. The lower limit of the viscosity is preferably 140 mPa · s, more preferably 180 mPa · s, still more preferably 200 mPa · s, and still more preferably 220 mPa · s. The upper limit of the viscosity is preferably 1000 mPa · s, more preferably 800 mPa · s, still more preferably 700 mPa · s, and even more preferably 600 mPa · s. From the viewpoint of improving the crosslinkability, it is preferably 100 mPa · s or more, and from the viewpoint of enhancing the image clarity of the coating film using the polyisocyanate composition, it is preferably 1500 mPa · s or less. The viscosity of the polyisocyanate composition of the present embodiment can be measured by using a polyisocyanate composition having a nonvolatile content purified to 98% by mass or more by using an E-type viscometer (manufactured by Tokimec). It can be measured by the method described in Examples described later.

  The isocyanate group content (NCO content) of the polyisocyanate composition of the present embodiment is preferably 21 to 25% by mass. The lower limit value of the NCO content rate is more preferably 22% by mass, and the upper limit value of the NCO content rate is more preferably 24% by mass. The NCO content is preferably 21% by mass or more from the viewpoint of improving the coating film properties such as coating film hardness, and is preferably 25% by mass or less from the viewpoint of reducing the diisocyanate monomer concentration. The NCO content can be obtained by back titration with 1N hydrochloric acid after neutralizing the isocyanate group of the polyisocyanate composition with an excess of 2N amine. In addition, NCO content rate is a value with respect to solid content of a polyisocyanate composition, and solid content of a polyisocyanate composition can be measured according to the method as described in the non-volatile content measurement mentioned later.

  The number average molecular weight of the solid content in the polyisocyanate composition of the present embodiment is not particularly limited, but is preferably 400 to 1,000. The lower limit of the number average molecular weight is more preferably 430, even more preferably 460, and even more preferably 480. The upper limit of the number average molecular weight is more preferably 800, still more preferably 700, and even more preferably 600. By setting the number average molecular weight to 400 or more, the yield of the resulting polyisocyanate composition tends to be further improved. By setting the number average molecular weight to 1,000 or less, the image clarity of the obtained coating film tends to be further improved. The number average molecular weight can be determined by gel permeation chromatography (GPC).

[Method for producing polyisocyanate composition]
Hereinafter, an example of the manufacturing method of the polyisocyanate composition of this embodiment is demonstrated. At least HDI (1,6-diisocyanatohexane) is used as a raw material for the polyisocyanate composition of the present embodiment. The polyisocyanate composition of the present embodiment includes an isocyanurate reaction for forming an isocyanurate group derived from an isocyanate group in a diisocyanate monomer, a uretdione reaction for forming a uretdione group, a ureton imino reaction for forming a ureton imino group, an imino The iminooxadiazine diionization reaction to form an oxadiazinedione group is carried out sequentially or in parallel in the presence of excess diisocyanate monomer, and after the reaction is completed, unreacted diisocyanate monomer is removed. Is obtained. It can also be obtained by mixing the above four reactions separately. From the viewpoint of availability, a method in which the above four reactions are sequentially performed or some of them are performed in parallel is preferable. Furthermore, alcohols such as alkyl monoalcohols and alkyl diols can be used in combination as auxiliary materials. Here, when using alcohols, as described above, allophanate groups / isocyanurate groups in the polyisocyanate composition are used. It is preferable that the molar ratio is in the range of 0.010 to 0.20.

  Preferably, a polymerization catalyst is added to the raw material, diisocyanate monomer containing HDI or the above-mentioned auxiliary raw material, the reaction is allowed to proceed until a predetermined degree of polymerization is reached, and then diisocyanate containing unreacted HDI as required. A polyisocyanate composition can be obtained by removing the monomer.

  When the isocyanurate group-containing polyisocyanate is derived from a diisocyanate monomer, an isocyanurate-forming catalyst is usually used. As the isocyanurate reaction catalyst, those having basicity are preferable. Specific examples of such an isocyanuration reaction catalyst are shown in the following 1) to 7).

1) Tetraalkylammonium hydroxide such as tetramethylammonium and tetraethylammonium, and organic weak acid salts such as acetic acid and capric acid;
2) Hydroxyalkylammonium hydroxides such as trimethylhydroxypropylammonium, trimethylhydroxyethylammonium, triethylhydroxypropylammonium, triethylhydroxyethylammonium and the like, and organic weak acid salts with, for example, acetic acid and capric acid;
3) Metal salts of alkyl carboxylic acids such as acetic acid, caproic acid, octylic acid, myristic acid, for example, tin, zinc, lead, sodium, potassium, etc .;
4) Metal alcoholates such as sodium and potassium;
5) Aminosilyl group-containing compounds such as hexamethyldisilazane;
6) Mannich bases;
7) Combined use of tertiary amines and epoxy compounds;

  From the viewpoint of catalyst efficiency, the above 1), 2) and 3) are preferable. More preferably, it is an organic weak acid salt of 1).

  The above-described catalyst is used in an amount of 10 to 1000 ppm, more preferably 10 to 500 ppm, and still more preferably 10 to 100 ppm with respect to the mass of the charged diisocyanate, and the isocyanuration reaction temperature is performed at 50 to 120 ° C. preferable. The lower limit of the reaction temperature is more preferably 54 ° C., further preferably 57 ° C., and still more preferably 60 ° C. Further, the upper limit value of the reaction temperature is more preferably 100 ° C., further preferably 90 ° C., still more preferably 80 ° C. When the isocyanuration reaction temperature is 120 ° C. or lower, changes in characteristics such as coloring tend to be suppressed.

  The uretdione group present in the polyisocyanate composition of the present embodiment can be obtained by using a uretdione reaction catalyst. Specific examples of the uretdiionization reaction catalyst include, but are not limited to, trialkylphosphines such as tri-n-butylphosphine and tri-n-octylphosphine, which are tertiary phosphines; And tris (dialkylamino) phosphine such as amino) phosphine; and cycloalkylphosphine such as cyclohexyl-di-n-hexylphosphine. Many of these compounds simultaneously promote the isocyanuration reaction and produce isocyanurate group-containing polyisocyanates in addition to uretdione group-containing polyisocyanates. When the desired yield is reached, a quencher for the uretdione reaction catalyst such as phosphoric acid or methyl paratoluenesulfonate is added to stop the uretdione reaction. The catalyst described above is used in an amount of 10 to 10000 ppm, preferably 10 to 1000 ppm, more preferably 10 to 500 ppm, based on the mass of the charged diisocyanate. The uretdione formation is preferably performed at a reaction temperature of 20 to 120 ° C. The lower limit of the reaction temperature is more preferably 25 ° C., further preferably 30 ° C., and still more preferably 35 ° C. Further, the upper limit value of the reaction temperature is more preferably 110 ° C., further preferably 100 ° C., and still more preferably 90 ° C. When the uretdioneization reaction temperature is 120 ° C. or lower, characteristic changes such as coloring tend to be suppressed.

  Moreover, a uretdione group can also be obtained by heating the monomer of a diisocyanate, without using the above uretdione-ized reaction catalysts. The heating temperature is preferably 130 ° C to 180 ° C. The lower limit of the heating temperature is more preferably 140 ° C, still more preferably 145 ° C, even more preferably 150 ° C, and even more preferably 155 ° C. Moreover, as an upper limit of heating temperature, More preferably, it is 170 degreeC, More preferably, it is 165 degreeC, More preferably, it is 162 degreeC, More preferably, it is 160 degreeC.

  Moreover, it is preferable that heating time is 0.2 hours-8.0 hours. The lower limit of the heating time is more preferably 0.4 hours, still more preferably 0.6 hours, still more preferably 0.8 hours, and even more preferably 1.0 hours. The upper limit of the heating time is more preferably 6.0 hours, further preferably 4.0 hours, still more preferably 3.0 hours, and even more preferably 2.0 hours. When the heating time is set to 0.2 hours or longer, viscosity tends to be reduced, and when the heating time is set to 8.0 hours or shorter, coloring of the polyisocyanate itself tends to be suppressed.

  When the polyisocyanate composition of the present embodiment is obtained without using the uretdione reaction catalyst, after the uretdione reaction by heating alone and the above-mentioned isocyanurate reaction are completed, the unreacted diisocyanate monomer can be removed. It is preferable from the viewpoints of reducing the unreacted diisocyanate monomer concentration, reducing the rate of change in molecular weight after storage of the obtained polyisocyanate composition, and reducing yellowing during high-temperature baking.

  The ureton imino group present in the polyisocyanate composition of the present embodiment is obtained by reacting using a ureton imination reaction catalyst. Specific examples of the ureton imination reaction catalyst include, but are not limited to, for example, 1-methyl-1-phosphorane, 1-ethyl-1-phosphorane, 1-propyl, which are heterocycle-containing phosphorus compounds. -1-phosphorane, 1-butyl-1-phosphorane, 1-pentyl-1-phosphorane, 1-hexyl-1-phosphorane, 1-octyl-1-phosphorane, 9-methyl-9-phosphabicyclononane, 9- Ethyl-9-phosphabicyclononane, 9-propyl-9-phosphabicyclononane, 9-butyl-9-phosphabicyclononane, 9-pentyl-9-phosphabicyclononane, 9-hexyl-9-phospha Bicyclononane, 9-octyl-9-phosphabicyclononane, 9-dodecyl-9-phosphabicyclononane, 9-eicosyl 9-phosphabicyclo triazacyclononane and the like. Many of these compounds simultaneously promote the isocyanurate formation reaction and the uretdione formation reaction, and in addition to the uretonimino group-containing polyisocyanate, produce isocyanurate group-containing polyisocyanate and uretdione group-containing polyisocyanate. When the desired yield is reached, a quencher for the ureton imination catalyst such as phosphoric acid, methyltoluenesulfonate, acid chloride and sulfur is added to stop the ureton imination reaction. The catalyst described above is used in an amount of 10 to 10000 ppm, preferably 10 to 1000 ppm, more preferably 10 to 500 ppm, based on the mass of the charged diisocyanate. Ureton iminization is preferably carried out at a reaction temperature of 20 to 120 ° C. The lower limit of the reaction temperature is more preferably 25 ° C, still more preferably 30 ° C, and even more preferably 35 ° C. Moreover, the upper limit of reaction temperature becomes like this. More preferably, it is 110 degreeC, More preferably, it is 100 degreeC, More preferably, it is 90 degreeC. When the ureton imination reaction temperature is 120 ° C. or lower, characteristic changes such as coloring tend to be suppressed.

  Moreover, a ureton imino group can also be obtained by heating the monomer of diisocyanate, without using the above ureton imination reaction catalyst. The heating temperature is preferably 130 ° C to 180 ° C. The lower limit of the heating temperature is more preferably 140 ° C, still more preferably 145 ° C, still more preferably 150 ° C, and even more preferably 155 ° C. The upper limit of the heating temperature is more preferably 170 ° C, further preferably 165 ° C, still more preferably 162 ° C, and still more preferably 160 ° C. When the heating temperature is 120 ° C. or higher, the ureton iminization reaction tends to proceed efficiently. Moreover, it exists in the tendency which can suppress coloring of polyisocyanate itself by making heating temperature into 180 degrees C or less.

  The heating time at the set temperature is preferably 0.2 hours to 8.0 hours. The lower limit of the heating time is more preferably 0.4 hours, still more preferably 0.6 hours, still more preferably 0.8 hours, and even more preferably 1.0 hours. The upper limit of the heating time is more preferably 6.0 hours, still more preferably 5.0 hours, still more preferably 4.0 hours, and even more preferably 3.0 hours. When the heating time is 0.2 hours or more, there is a tendency that low viscosity can be exhibited, and when the heating time is 8.0 hours or less, the coloration of the polyisocyanate itself tends to be suppressed. It is in.

  Furthermore, it is preferable that the rate of temperature increase / decrease to the ureton imination reaction temperature is 0.5 ° C./min to 2.5 ° C./min. The lower limit of the speed is more preferably 0.6 ° C./min, still more preferably 0.8 ° C./min, and even more preferably 1.0 ° C./min. Moreover, as an upper limit of the said speed | rate, it is 2.3 degreeC / min more preferably, More preferably, it is 2.15 degreeC / min, More preferably, it is 2.0 degreeC / min. When the rate of temperature increase / decrease is 0.5 ° C./min or more, the production time tends to be completed in a short time. When the rate of temperature increase / decrease is 2.5 ° C./min or less, the ureton iminization reaction tends to proceed efficiently. When the polyisocyanate composition of this embodiment is obtained without using a ureton imination reaction catalyst, the unreacted diisocyanate monomer is removed after the ureton iminization reaction by heating alone, the above-described isocyanurate reaction, and uretdione reaction are completed. It is preferable to reduce the concentration of unreacted diisocyanate monomer and reduce the amount of diisocyanate monomer increased after storage of the obtained polyisocyanate composition.

  The isocyanurate / uretdione-bonded tetramer present in the polyisocyanate composition of the present embodiment can be obtained by using the following uretdione-forming reaction catalyst. Specific examples of the uretdiionization reaction catalyst include, but are not limited to, trialkylphosphines such as tri-n-butylphosphine and tri-n-octylphosphine, which are tertiary phosphines; And tris (dialkylamino) phosphine such as amino) phosphine; and cycloalkylphosphine such as cyclohexyl-di-n-hexylphosphine. Many of these compounds also promote isocyanuration reactions in addition to uretdioneation reactions. Therefore, a uretdione group-containing polyisocyanate, an isocyanurate group-containing polyisocyanate, and an isocyanurate / uretdione-bonded tetramer are produced. When the desired yield is reached, a quencher for the uretdione reaction catalyst such as phosphoric acid or methyl paratoluenesulfonate is added to stop the uretdione reaction. The catalyst described above is used in an amount of 10 to 10000 ppm, more preferably 10 to 1000 ppm, and still more preferably 10 to 500 ppm, based on the mass of the charged diisocyanate. The uretdione formation is preferably performed at a reaction temperature of 20 to 120 ° C. As a lower limit of reaction temperature, More preferably, it is 25 degreeC, More preferably, it is 30 degreeC, More preferably, it is 35 degreeC. Moreover, the upper limit of reaction temperature becomes like this. More preferably, it is 110 degreeC, More preferably, it is 100 degreeC, More preferably, it is 90 degreeC. When the uretdioneization reaction temperature is 120 ° C. or lower, characteristic changes such as coloring tend to be suppressed.

  Further, an isocyanurate / uretdione bond structure can be obtained by heating at 120 to 180 ° C. after the isocyanuration reaction without using the uretdioneation reaction catalyst as described above. As a lower limit of heating temperature, More preferably, it is 130 degreeC, More preferably, it is 140 degreeC, More preferably, it is 145 degreeC. Moreover, as an upper limit of heating temperature, More preferably, it is 175 degreeC, More preferably, it is 170 degreeC, More preferably, it is 165 degreeC.

  Moreover, it is preferable that heating time is 0.2 hours-8.0 hours. The lower limit of the heating time is more preferably 0.4 hours, still more preferably 0.6 hours, still more preferably 0.8 hours, and even more preferably 1.0 hours. The upper limit of the heating time is more preferably 6.0 hours, further preferably 4.0 hours, still more preferably 3.0 hours, and even more preferably 2.0 hours. When the heating time is set to 0.2 hours or longer, viscosity tends to be reduced, and when the heating time is set to 8.0 hours or shorter, coloring of the polyisocyanate itself tends to be suppressed. When the polyisocyanate composition of the present embodiment is obtained without using the uretdione reaction catalyst, the isocyanurate / uretodione bond tetramer is formed by heating after the isocyanuration reaction, and then the unreacted diisocyanate. It is preferable to remove the monomer from the viewpoint of reducing the concentration of the unreacted diisocyanate monomer and reducing the amount of increase in the diisocyanate monomer after storage of the obtained polyisocyanate composition.

  The allophanate group present in the polyisocyanate composition of the present embodiment can be obtained by using an alcohol such as alkyl monoalcohol and alkyl diol in combination with a diisocyanate monomer containing HDI and using an allophanate reaction catalyst. Although alcohol which can be used for this embodiment is not limited to the following, alcohol formed only with carbon, hydrogen, and oxygen is preferred, and monoalcohol is more preferred. More preferred is an alcohol having a molecular weight of 200 or less. Examples of the alcohol include monoalcohols such as methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol, octanol, and nonanol; ethylene glycol, 1,3-butanediol, neopentyl glycol, 2-ethylhexanediol, and the like. These two alcohols may be used, and two or more of these may be used in combination.

  The addition amount of the alcohol is not limited to the following, but the equivalent ratio of the isocyanate group of the diisocyanate monomer containing HDI to the hydroxyl group of the alcohol is 1000/1 to 10/1, preferably 1000/1 to 100/1. is there. When the upper limit of the equivalent ratio is 10/1 or more, the average number of isocyanate groups tends to be ensured. Specific compounds of the allophanatization reaction catalyst include, but are not limited to, for example, tin 2-ethylhexanoate, dibutyltin, which are alkyl carboxylates such as tin, lead, zinc, bismuth, zirconium, zirconyl, and the like. Organic tin compounds such as dilaurate; Organic lead compounds such as lead 2-ethylhexanoate; Organic zinc compounds such as zinc 2-ethylhexanoate; Bismuth 2-ethylhexanoate; Zirconium 2-ethylhexanoate; 2-ethylhexanoic acid Zirconyl; and the like.

  When the desired yield is obtained, the allophanatization reaction is stopped by adding a deactivating agent for the allophanate reaction catalyst such as phosphoric acid or methyl paratoluenesulfonate. The catalyst described above is used in an amount of 10 to 10000 ppm, more preferably 10 to 1000 ppm, and still more preferably 10 to 500 ppm, based on the mass of the charged diisocyanate. Allophanatization is preferably performed at a reaction temperature of 60 to 160 ° C. The lower limit of reaction temperature becomes like this. More preferably, it is 70 degreeC, More preferably, it is 80 degreeC, More preferably, it is 90 degreeC. Moreover, the upper limit of reaction temperature becomes like this. More preferably, it is 155 degreeC, More preferably, it is 150 degreeC, More preferably, it is 145 degreeC. When the allophanatization reaction temperature is 160 ° C. or lower, changes in characteristics such as coloring tend to be suppressed.

  Moreover, it is preferable that heating time is 0.2 hours-8.0 hours. The lower limit of the heating time is more preferably 0.4 hours, still more preferably 0.6 hours, still more preferably 0.8 hours, and even more preferably 1.0 hours. The upper limit of the heating time is more preferably 6.0 hours, further preferably 4.0 hours, still more preferably 3.0 hours, and even more preferably 2.0 hours. When the heating time is 0.2 hours or more, there is a tendency that low viscosity can be exhibited, and when the heating time is 8.0 hours or less, the coloration of the polyisocyanate itself tends to be suppressed. It is in.

  The above isocyanuration reaction catalyst can also be an allophanatization reaction catalyst. When performing the allophanatization reaction using the above isocyanurate reaction catalyst, the isocyanurate group-containing polyisocyanate is naturally produced. From the viewpoint of economic productivity, it is preferable to use the above isocyanurate reaction catalyst as the allophanate reaction catalyst and simultaneously perform the allophanate reaction and the isocyanurate reaction.

The above-described isocyanurate reaction, uretdione reaction, ureton iminization reaction, and isocyanurate / uretdione bond tetramer formation reaction can be performed sequentially or some of them can be performed in parallel.
Further, when the allophanation reaction is involved, preferably, the isocyanuration reaction and the allophanation reaction are preceded in parallel, and thereafter, the uretdioneation reaction, the ureton imination reaction, the isocyanurate / uretdione bond tetramer formation reaction are performed. Do.
Isocyanurate reaction and allophanate reaction are simultaneously performed using a common catalyst, followed by thermal uretdione reaction, ureton iminization reaction, isocyanurate / uretdione bond tetramer formation reaction, simplifying the production process From the viewpoint of, it is more preferable.

  When the polymerization reaction reaches a desired degree of polymerization, the polymerization reaction is stopped. The termination of the polymerization reaction is not limited to the following, for example, neutralizing the polymerization reaction catalyst by adding an acidic compound of phosphoric acid, acidic phosphate ester, sulfuric acid, hydrochloric acid, sulfonic acid compound to the reaction solution, or It can be achieved by inactivating the polymerization reaction catalyst by thermal decomposition, chemical decomposition, or the like.

  Since the reaction solution immediately after stopping the reaction usually contains an unreacted diisocyanate monomer, it is preferable to remove this by a post-treatment such as a thin film evaporator or extraction. The concentration of the diisocyanate monomer contained in the polyisocyanate composition is preferably controlled to 1.0% by mass or less by performing the post-treatment. The upper limit value of the diisocyanate monomer concentration in the polyisocyanate composition of the present embodiment is more preferably 0.7% by mass or less, still more preferably 0.5% by mass or less, and still more preferably 0.3% by mass. Or less, more preferably 0.2% by mass or less. By setting the diisocyanate monomer concentration to be equal to or lower than the above upper limit value, the toxicity of the polyisocyanate composition of this embodiment can be further reduced, and the safety tends to be improved.

  The polyisocyanate composition of the present embodiment is obtained by filtration after stopping the reaction or after removing unreacted polyisocyanate monomer by a thin film evaporator, extraction or the like. By filtering, the phosphorus concentration contained in the polyisocyanate composition can be adjusted to 1 ppm to 50 ppm. For the filtration, for example, a filter such as a membrane filter or depths can be used. The pore size of the filter is preferably 1 μm to 10 μm, and more preferably 1 μm to 8 μm. By setting the pore size to 1 μm or more, the productivity of the polyisocyanate composition can be improved, and by setting the pore size to 10 μm or less, the phosphorus concentration can be further reduced. Although it does not specifically limit as a raw material, PTFE, nylon, a polypropylene, polyester, etc. can be used. Filtration may be performed once or twice or more. The temperature at which filtration is performed depends on the material of the filter, but is preferably 30 ° C to 100 ° C. By setting the temperature at which filtration is performed to 30 ° C. or higher, the viscosity of the polyisocyanate composition or the reaction liquid of the polyisocyanate composition can be lowered, and filtration can be performed without reducing productivity. By setting the temperature at which filtration is performed to 100 ° C. or less, the phosphorus concentration can be further reduced.

[Water-based paint composition]
The polyisocyanate composition of the present embodiment can be suitably used as a curing agent for an aqueous coating composition. The aqueous coating composition of the present embodiment preferably contains the above-described polyisocyanate composition of the present embodiment, an aqueous acrylic polyol, and a surface tension adjusting agent.

  The water-based acrylic polyol in the water-based coating composition of the present embodiment is suitably used from the viewpoint of weather resistance, chemical resistance, and hardness, and the type is not particularly limited. As the aqueous acrylic polyol, a resin in which the aqueous acrylic polyol is dispersed or emulsified in a medium containing water as a main component and, if necessary, a small amount of an organic solvent is preferably used. The composition, glass transition temperature, particle diameter, molecular weight, hydroxyl group concentration, and the like of the resin can be designed according to the use and purpose of the aqueous coating composition, and the resin is commercially available as a number of products. Moreover, what compounded polyester-type resin, polyurethane-type resin, etc. in the aqueous | water-based acrylic polyol can also be used.

  The glass transition temperature of the resin varies depending on the application and purpose of the aqueous coating composition, and is not limited. Generally, however, it is set to a low value in applications that require flexibility such as an elastic coating, and hardness such as a hard coating is required. For high usage, set to a high value. Usually, the glass transition temperature is about -50 ° C to 80 ° C.

  The particle diameter of the resin is usually set to approximately 50 nm to 400 nm as an average particle diameter from the viewpoints of dispersion stability, viscosity, and various performances of the aqueous coating composition to be formed. From the viewpoint of mixing stability with the main agent in the present embodiment, the particle diameter of the resin is preferably 200 nm or less.

  The hydroxyl group concentration of the resin is appropriately set depending on the application and purpose, and is usually about 0.5% or more and 5% or less as the weight% of the hydroxyl group in the resin component.

The aqueous acrylic polyol is one or two or more of ethylenically unsaturated bond-containing monomers having a hydroxyl group and one or two of other ethylenically unsaturated bond-containing monomers copolymerizable therewith. It is obtained by copolymerizing the above.
The copolymerization is carried out by general solution polymerization or emulsion polymerization, and a chain transfer agent such as mercaptans is used for adjusting the molecular weight. In the case of emulsion polymerization, a resin emulsified in water can be obtained directly, but in the case of solution polymerization, it is necessary to copolymerize an amount of a carboxyl group-containing monomer necessary for water dispersion performed after polymerization. After completion of the polymerization, the carboxyl group is neutralized with a basic compound such as ammonia or amine, and water is added to obtain an aqueous dispersion of polyol. Preferably, the organic solvent used during the solution polymerization is then removed by distillation.

  Examples of the ethylenically unsaturated bond-containing monomer having a hydroxyl group include 2-hydroxyethyl acrylate, 3-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, 2-hydroxyethyl methacrylate, Examples include methacrylic acid-3-hydroxypropyl, methacrylic acid-4-hydroxybutyl, and the like. Among them, preferred are 2-hydroxyethyl acrylate and 2-hydroxyethyl methacrylate.

  Examples of the other copolymerizable monomer having an ethylenically unsaturated bond include ethyl acrylate, propyl acrylate, isopropyl acrylate, acrylate-n-butyl, acrylate isobutyl, and acrylate-n-hexyl. Acrylates such as cyclohexyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, etc .; methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, -n-butyl methacrylate, isobutyl methacrylate, methacryl Methacrylic acid esters such as acid-n-hexyl, cyclohexyl methacrylate, 2-ethylhexyl methacrylate, and lauryl methacrylate; unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, and itaconic acid; , Methacrylamide, N, N-methylenebisacrylamide, diacetone acrylamide, etc .; glycidyl group-containing monomers such as glycidyl methacrylate; vinyls such as styrene, vinyl toluene, vinyl acetate, acrylonitrile, dibutyl fumarate Monomer; Hydrolyzable silyl group-containing monomers such as vinyltrimethoxysilane, vinylmethyldimethoxysilane, and γ- (meth) acryloxypropyltrimethoxysilane.

  Commercially available water-based acrylic polyols include Setaqua 6510, Setaqua 6515, Setaqua 6520 (manufactured by Nuplex Resin), Macrynal VSM2521w, Macrynal VSM6299w, Macryal SM6810, Macryn SM6825, Macryl SM6810, and Macrial SM6825.

  As the polyester resin, for example, a 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, terephthalic acid alone or A mixture, and optionally a sulfonate-containing polycarboxylic acid and selected from the group of ethylene glycol, propylene glycol, butylene glycol, hexylene glycol, diethylene glycol, neopentyl glycol, trimethylolpropane, pentaerythritol, glycerin, etc. It can be obtained by condensation reaction with a single or mixture of polyhydric alcohols or by ring-opening polymerization of ε-caprolactone using polyhydric alcohols. The molecular weight is adjusted by adjusting the degree of polymerization. After completion of the polymerization, a carboxyl group in the polyester resin can be neutralized with a basic compound such as ammonia or amine, and water can be added to obtain a water dispersion of the polyester resin. When an organic solvent is used for polymerization or water dispersion, the organic solvent is preferably removed by distillation after water dispersion.

  As the polyurethane resin, what is commonly referred to as polyurethane dispersion is used, for example, a diisocyanate compound such as isophorone diisocyanate, hexamethylene diisocyanate, methylene diphenyl diisocyanate, hydrogenated methylene diphenyl diisocyanate, and polyester diol or polycarbonate diol. A prepolymerization reaction by reaction is performed in the presence of a necessary amount of a carboxyl group-containing diol such as dimethylolpropionic acid, and after neutralizing the carboxyl group with a tertiary amine, etc., water is dispersed by adding water, Thereafter, it can be obtained by adding a diamine compound such as ethylene diamine or isophorone diamine immediately and performing chain extension. The molecular weight is adjusted depending on the ratio of isocyanate groups to hydroxyl groups during the prepolymerization reaction and the conditions of chain extension. When an organic solvent is used in the prepolymerization reaction, the organic solvent is preferably removed by distillation after chain extension. In addition, since the polyurethane dispersion itself is a tough resin, the main component for the aqueous two-component curable resin in the present embodiment has a hydroxyl group in addition to the one having a predetermined amount of hydroxyl group introduced therein. Even when it has, it can use what has a small hydroxyl group content.

  In the production of the aqueous coating composition of the present embodiment, considering the reaction between the isocyanate group in the polyisocyanate composition as a curing agent and water, the ratio of the hydroxyl group in the isocyanate group and the aqueous acrylic polyol is It is preferable to carry out under the condition that becomes excessive. Usually, the molar ratio of isocyanate groups to hydroxyl groups is set from 1.1 times to 1.5 times. In addition, it is preferable to dilute the polyisocyanate composition in advance with an organic solvent that does not have reactivity with the isocyanate group because of the effect of improving the blending stability with the aqueous main agent.

  As an organic solvent that can be used for dilution, ethylene glycol monobutyl ether acetate, butyl acetate, propylene glycol monomethyl ether acetate, diethylene glycol diethyl ether, dipropylene glycol dimethyl ether, butyl carbitol acetate, etc. are used alone or in combination. Can do. Among these, ethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, diethylene glycol diethyl ether, and dipropylene glycol dimethyl ether are preferable because they have a high effect of improving the image clarity of a coating film obtained from an aqueous coating composition. However, from the viewpoints of global environmental protection and occupational safety and health, it is desirable to reduce the amount of these organic solvents as much as possible. The amount of organic solvent used for dilution is 50% by mass based on the total amount with the curing agent. The following is preferable.

  In addition, in order to improve the appearance of the coating film obtained from the aqueous coating composition, it is also possible to previously mix a so-called water-dispersible polyisocyanate containing a hydrophilic group with the polyisocyanate composition of the present embodiment. However, from the viewpoint of water resistance and weather resistance of the formed cured resin composition, it is preferably 50% by mass or less based on the total amount with the polyisocyanate composition of the present embodiment. Even when such a water-dispersible polyisocyanate is mixed, it can be diluted in advance with the above-mentioned organic solvent in order to reduce the viscosity and improve the convenience in handling. In this case as well, it is desirable to reduce the amount of the organic solvent used as much as possible. The amount of the organic solvent used for dilution is 30% by mass based on the total amount of the polyisocyanate composition of the present embodiment and the water-dispersible polyisocyanate. The following is preferable.

  The aqueous coating composition can be produced using hand stirring or a stirrer. The time required for blending is usually about 1 to 30 minutes, depending on the blending method.

  It is preferable to use a surface tension adjusting agent for the water-based coating composition of this embodiment in order to impart coating film appearance. The type of the surface tension adjusting agent is not particularly limited, and silicon-based, acrylic-based and the like can be used. The surface tension adjusting agent is preferably used in an amount of 0.05% by mass to 5% by mass with respect to the resin content of the aqueous polyol. When the surface tension modifier is 0.05% by mass or more, coating film appearance can be imparted, and when the surface tension modifier is 5% by mass or less, water resistance can be imparted.

  A commercial item can be used as said silicon system, for example, BYK-302, BYK-307, BYK-325, BYK-331, BYK-333, BYK-342, BYK-347, BYK-348, BYK-. 349, BYK-378, BYK-3455 (manufactured by BYK), Tego wet KL245, Tego wet 250, Tego wet 260, Tego wet 265, Tego wet 270, and Tego wet 280 (Evoic Tego). These may be used alone or in combination.

  A commercial item can be used as said acrylic type, for example, BYK-381, BYK-3441 (made by BYK) etc. are mentioned. These may be used alone or in combination.

  In the production of the aqueous coating composition, if necessary, for example, a curing accelerator such as an organic metal compound such as carboxylic acid such as tin, zinc and lead; for example, an antioxidant such as hindered phenol; UV absorbers such as triazole and benzophenone; light stabilizers such as hindered amines; pigments such as titanium oxide, carbon black, indigo, quinacridone, pearl mica, and aluminum paste; other rheology control agents; dispersants; It is possible to add additives such as;

  Inclusion of an ultraviolet absorber and / or a light stabilizer in the aqueous coating composition is preferable for imparting high weather resistance. When an ultraviolet absorber and a light stabilizer are used in combination, a coating film obtained by curing an aqueous coating composition is preferable because it is particularly excellent in weather resistance. It is preferable to use 0.1 mass%-5 mass% of ultraviolet absorbers and / or light stabilizers with respect to the resin content of the aqueous polyol.

  Specific examples of the benzotriazole type ultraviolet absorber include 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, 2- (2′-hydroxy-5′-tert-butylphenyl) benzotriazole, 2 -(2'-hydroxy-3 ', 5'-di-tert-butylphenyl) benzotriazole, 2- (2-hydroxy-5-tert-octylphenyl) benzotriazole, 2- (2-hydroxy-3,5 -Di-tert-octylphenyl) benzotriazole, 2- [2′-hydroxy-3 ′, 5′-bis (α, α′-dimethylbenzyl) phenyl] benzotriazole), methyl-3- [3-tert- Butyl-5- (2H-benzotriazol-2-yl) -4-hydroxyphenyl] propionate and polyethylene Condensate with N-glycol (molecular weight 300) (BASF, product name: TINUVIN 1130), isooctyl-3- [3- (2H-benzotriazol-2-yl) -5-tert-butyl-4-hydroxyphenyl] Propionate (manufactured by BASF, product name: TINUVIN384), 2- (3-dodecyl-5-methyl-2-hydroxyphenyl) benzotriazole (manufactured by BASF, product name: TINUVIN571), 2- (2′-hydroxy-3) '-Tert-butyl-5'-methylphenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy-3', 5'-di-tert-amylphenyl) benzotriazole, 2- (2'-hydroxy -4'-octoxyphenyl) benzotriazole, 2- [2'-hydroxy-3 -(3 ", 4", 5 ", 6" -tetrahydrophthalimidomethyl) -5'-methylphenyl] benzotriazole, 2,2-methylenebis [4- (1,1,3,3-tetra Methylbutyl) -6- (2H-benzotriazol-2-yl) phenol], 2- (2H-benzotriazol-2-yl) -4,6-bis (1-methyl-1-phenylethyl) phenol (BASF) And a product name: TINUVIN900).

  Examples of the triazine ultraviolet absorber include TINUVIN400 (product name, manufactured by BASF).

  Specific examples of the hindered amine light stabilizer include bis (2,2,6,6-tetramethyl-4-piperidyl) succinate, bis (2,2,6,6-tetramethylpiperidyl) sebacate, bis (1, 2,2,6,6-pentamethyl-4-piperidyl) 2- (3,5-di-tert-butyl-4-hydroxybenzyl) -2-butylmalonate, 1- [2- [3- (3 5-Di-tert-butyl-4-hydroxyphenyl) propynyloxy] ethyl] -4- [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propynyloxy] -2,2,6 6-tetramethylpiperidine, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate and methyl-1,2,2,6,6-pentamethyl-4-piperidyl-sebake Mixture (BASF, product name: TINUVIN292), bis (1-octoxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate, TINUVIN123 (product name, manufactured by BASF), etc. .

  The coating film obtained by curing the aqueous coating composition of this embodiment is excellent in image clarity. Therefore, automobiles, buses, railway vehicles, construction machinery, agricultural machinery, building floors, walls and roofs, metal products, mortar and concrete products, woodwork products, plastic products, ceramic building materials such as calcium silicate boards and plaster boards, etc. It can be preferably used, and general methods such as spray coating, roller coating, curtain flow coating, air knife coating, gravure coating and brush coating can be used.

  Although the water-based paint composition in the present embodiment has a relatively long pot life, it is preferably used for about 1 to 3 hours after manufacture, although it varies depending on the ambient temperature. .

[Method for producing coating film]
The coating film of the present embodiment is a coating film obtained by curing the aqueous coating composition of the present embodiment. Moreover, the manufacturing method of the coating film of this embodiment has the process of hardening the coating composition of this embodiment. Curing can be performed by natural drying, or by heat drying with warm air or infrared rays. Since it is comprised in this way, the coating film of this embodiment is excellent in image clarity.

[Moisture stabilization method]
The moisture stabilization method of the polyisocyanate composition of the present embodiment is obtained from an aliphatic diisocyanate containing 1,6-diisocyanatohexane, and isocyanurate group, uretdione group, uretonimino group, and iminooxadiazine It is a moisture stabilization method of a polyisocyanate composition containing a dione group. The molar ratio of the uretonimino group to the isocyanurate group (uretonimino group / isocyanurate group) is set to 0.0010 to 0.0050, and the molar ratio of the iminooxadiazinedione group to the isocyanurate group (imino (Oxadiazindione group / isocyanurate group) is 0.00050 to 0.30. In the polyisocyanate composition of the present embodiment, the molar ratio of (uretonimino group / isocyanurate group) and the molar ratio of (iminooxadiazinedione group / isocyanurate group) are within the above numerical range. In addition, moisture stability is improved.

  From the viewpoint of stabilizing the moisture of the polyisocyanate composition of the present embodiment, the molar ratio of (uretonimino group / isocyanurate group) is preferably 0.0012 to 0.0045, more preferably 0.0015 to 0.0040. Preferably, it is 0.0020 to 0.0035. The molar ratio of (iminooxadiazinedione group / isocyanurate group) is preferably 0.0008 to 0.20, more preferably 0.0012 to 0.10, and still more preferably 0.0016 to 0.050. More preferably, it is 0.0020-0.025. “Moisture stability” refers to the property that the polyisocyanate composition of the present embodiment can be maintained without being in a gel state for a long time when left under saturated humidity conditions. Specifically, it can be verified by the method described in Examples described later.

  Hereinafter, although this embodiment is demonstrated in more detail based on an Example and a comparative example, this embodiment is not limited at all by the following examples.

[Measurement method of characteristics]
<Viscosity>
The viscosity was measured at 25 ° C. using an E-type viscometer (manufactured by Tokimec). In the measurement, a standard rotor (1 ° 34 ′ × R24) was used. The number of rotations was as follows.
100 rpm (when less than 128 mPa · s)
50 rpm (128 mPa · s or more and less than 256 mPa · s)
20 rpm (256 mPa · s or more and less than 640 mPa · s)
10 rpm (in the case of 640 mPa · s or more and less than 1280 mPa · s)
5 rpm (in the case of 1280 mPa · s or more and less than 2560 mPa · s)
In addition, the non volatile matter of the polyisocyanate composition manufactured by each Example and each comparative example mentioned later was investigated by the method of the following description, and what was the value of 98 mass% or more was used for the measurement as it was.

<Nonvolatile content>
The non-volatile content was calculated | required by the following formula from the residual amount at the time of heating a polyisocyanate composition at 105 degreeC 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

<NCO content>
The NCO content (mass%) was determined by back titration with 1N hydrochloric acid after neutralizing the isocyanate group in the measurement sample with excess 2N amine. In addition, the non volatile matter of the polyisocyanate composition manufactured by the Example and comparative example which are mentioned later was investigated by the method mentioned above, and the thing whose value was 98 mass% or more was used for the measurement as it was.

<HDI monomer mass concentration>
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 to 0.04 g of nitrobenzene (internal standard solution) was added and precisely weighed. Furthermore, after adding about 9 mL of ethyl acetate, the lid was tightly mixed well to prepare a sample. The above prepared solution was analyzed by gas chromatography under the following conditions and quantified.
Apparatus: SHIMADZU Co., Ltd. GC-8A
Column: Shinwa Kako Co., Ltd. Silicone OV-17
Column oven temperature: 120 ° C
Injection / detector temperature; 160 ° C

<Mole ratio of uretdione group / isocyanurate group, uretonimino group / isocyanurate group, iminooxadiazinedione group / isocyanurate group, allophanate group / isocyanurate group>
By measuring ¹³ C-NMR using Avance 600 (trade name) manufactured by Bruker Biospin, uretdione group / isocyanurate group, ureton imino group / isocyanurate group, iminooxadiazinedione group / isocyanurate group, allophanate group / isocyanurate The molar ratio of groups was determined respectively. Specific measurement conditions were as follows.

¹³ C-NMR apparatus: AVANCE 600 (manufactured by Bruker Biospin)
Cryoprobe: CP DUL 600S3 C / HD-05 Z
(Bruker Biospin)
Resonance frequency: 150 MHz
Concentration: 60 wt / vol%
Shift standard: CDCl ₃ (77 ppm)
Integration number: 10,000 times Pulse program: zgpg30 (proton complete decoupling method, waiting time 2 seconds)

In addition, in the said measurement, the integrated value of the following signals was divided | segmented by the number of the carbon currently measured, and each molar ratio was calculated | required from the value.
Isocyanurate group: around 148.6 ppm: integral value ÷ 3
Uretodione group: Around 157.5 ppm: integral value / 2
Allophanate group: around 154 ppm: integral value / 1
Uretonimino group: around 159.5 ppm: integral value ÷ 1
Iminooxadiazinedione group: around 137.3 ppm: integral value ÷ 1

<Ratio of isocyanurate / uretdione bond tetramer / isocyanurate trimer>
Isocyanurate-uretdione bond polymerized with four 1,6-isocyanatohexanes to isocyanurate trimer polymerized with three 1,6-isocyanatohexanes in polyisocyanate composition (also referred to as compound α) The abundance ratio of the tetramer (also referred to as compound β) was determined according to the following method. Specifically, the terminal isocyanate groups of compound α and compound β in the polyisocyanate composition were urethanated with methanol and analyzed with a liquid chromatograph mass spectrometer (LC / MS). The sample preparation method and measurement method are described below.

(1) Preparation method of sample 100 mg of polyisocyanate compositions were weighed, and methanol was added so that it might become 10 mg / mL. Then, it left still for 2 days, the isocyanate group which exists was made to react with methanol completely, and the methanol solution was prepared.

(2) Measuring method About the methanol solution obtained above, it measured using the following apparatuses.

・ LC
Device: Waters ACQUITY UPLC
Column: Phenomenex, Kinetex 2.6μ XB-C18 100A
(Inner diameter 2.1mm, length 50mm)
Column temperature: 40 ° C
Detection: 220nm
Flow rate: 0.3 mL / min Mobile phase: A and B liquid gradients below
A = water (0.05% formic acid), B = acetonitrile (0.05% formic acid)
Gradient conditions
Time (minutes) A% B%
0 60 40
12 0 100
12.1 60 40
20 60 40
Injection volume: 1 μL
・ MS
Equipment: Waters, Synapt G2
Ionization: ESI
Mode: Positive
Scan range: m / z 250-2000
Isocyanurate trimer methanol adduct polymerized with 3 HDIs (compound α; the following formula (VII)), methanol adducts of isocyanurate / uretdione-bonded tetramers polymerized with 4 HDIs (compound β) The peak area ratio (β / α) of the following formula (VIII)). Compound α was detected with detection ions (m / z) 601 at a retention time of about 1.55 minutes. Compound β was detected with detection ions (m / z) 769 at a retention time of around 3.44 minutes. In the following formulas (VII) and (VIII), Me represents a methyl group.

<Increase amount of diisocyanate monomer (DI) after storage>
After storing the polyisocyanate composition in a nitrogen atmosphere at 40 ° C. for 30 days, the diisocyanate monomer concentration was measured by gas chromatographic measurement under the above-mentioned measurement conditions for the HDI monomer mass concentration. Increase in diisocyanate monomer concentration after storage is 0.15% by mass or less “◎”, more than 0.15% by mass 0.20% by mass or less “◯”, more than 0.20% by mass 0.25% by mass or less “ The case where “Δ” exceeds 0.25% by mass is represented by “x”.

<Moisture stability>
A polyisocyanate composition (5.0 g) and butyl acetate (5.0 g) were mixed, and the number of days until the gelled state was reached was evaluated at 20 ° C. and saturated humidity. When the number of days until gelation is less than 2 days, “×”, when 2 days or more and less than 3 days, “△”, when 3 days or more and less than 4 days, “○”, and 4 days or more The case was designated as “◎”.

<Measurement of phosphorus concentration in polyisocyanate composition>
The phosphorus concentration (mass basis) in the polyisocyanate composition was measured by the following method. First, about 1.5 g of a sample was weighed into a conical beaker, 20 mL of concentrated sulfuric acid was added, and the mixture was heated on a heater. After completion of the decomposition, 5 mL of hydrogen peroxide water was added. Then, it concentrated on the heater until the decomposition liquid became about 3-5 mL. After cooling, it was poured into a 50 mL capacity digital tube with pure water, made up to 25 mL, mixed, and used as a measurement sample. A measurement sample was introduced into a plasma emission spectrometer set to a wavelength of 213.618 nm and quantified.
Apparatus: Plasma emission spectroscopic analyzer Thermo Fisher Scientific Model: iCAP6300Duo
Measurement wavelength: 213.618 nm

<Main ingredient mixing stability>
A water-based coating composition described later was applied to a glass plate so that the dry film thickness was about 40 μm, and dried for 7 days in an atmosphere of 23 ° C./50% RH. Aggregates present on the surface of the 5 cm × 5 cm coating film were confirmed, and 1 or less was evaluated as ◯, 2 to 5 as Δ, and 6 or more as X.

<Glossy>
Sprayed with a commercially available solvent-based two-component acrylic urethane white enamel coating on a deoiled aluminum plate in advance, then dried at 80 ° C for 2 hours, cured at room temperature for 2 weeks, and 60% gloss value of 10% A substrate whose surface was polished with # 1000 sandpaper was prepared as a substrate until it became the following. On the substrate, an aqueous coating composition described later was applied using an air spray so that the dry film thickness was about 40 μm, and dried for 7 days in an atmosphere of 23 ° C./50% RH. Thereafter, a gloss value of 60 degrees was measured under the conditions of JIS Z8741 using a gloss meter (digital variable angle gloss meter UDV-6P (trade name) manufactured by Suga Test Instruments Co., Ltd.).
The 60 ° gloss value was evaluated as ○ when 90% or more, △ when less than 90% and 80% or more, and × when less than 80%.

<Image clarity>
A mild steel plate (SPCC SB) was deoiled with acetone, and an aqueous coating composition described later was applied onto the degreased mild steel plate using an air spray so that the dry film thickness was about 40 μm, and 23 ° C./50 It was dried for 7 days under an atmosphere of% RH. Thereafter, the image clarity (DOI value) was measured under the conditions of ASTM-D5767 using a mapping meter (Low Point IQ-S (trade name) manufactured by Konica Minolta, Inc.).
The image clarity was evaluated as ◎ for 80 or more, ◯ for 60 or more and less than 80, and × for less than 60.

(Preparation of polyisocyanate composition)
Example 1
A four-necked flask equipped with a stirrer, thermometer, reflux condenser, nitrogen blowing tube, and dropping funnel is placed in a nitrogen atmosphere, charged with 6,000 g of HDI and 7.0 g of isobutanol, and the temperature inside the reactor under stirring is increased. Hold at 80 ° C. for 2 hours. Thereafter, 5.0 g of a solution obtained by diluting the isocyanuration catalyst trimethyl-2-methyl-2-hydroxyethylammonium hydroxide with isobutanol to 5% by mass is added to conduct an isocyanuration reaction, and the NCO content of the reaction solution is When it reached 44.6% by mass, phosphoric acid was added to stop the reaction. The uretdione dimer concentration increased by this reaction was 1.0 mass% or less. Thereafter, the temperature was raised to 160 ° C. at a temperature raising rate of 1.6 ° C./min, and held at 160 ° C. for 1 hour. Thereafter, the temperature was lowered to 40 ° C. at a rate of 1.5 ° C./min. This heating produced a uretdione group, a uretonimino group, and an isocyanurate / uretdione bond structure. The obtained reaction solution was filtered using a PTFE filter (trade name: T300A090C, manufactured by ADVANTEC) having a pore size of 3 μm. Using a thin film evaporator, purification was performed twice at 160 ° C. and 0.2 Torr, non-volatile content 99.5% by mass, viscosity 520 mPa · s (25 ° C.), NCO content 23.1% by mass, HDI monomer concentration A polyisocyanate composition P-1 having 0.11% by mass and a phosphorus concentration of 4 ppm was obtained.
Further, the molar ratio of uretdione group / isocyanurate group was 0.32, the molar ratio of uretonimino group / isocyanurate group was 0.0022, and the molar ratio of iminooxadiazinedione group / isocyanurate group was ¹³ C-NMR measurement. The molar ratio of 0.0038 and allophanate group / isocyanurate group was 0.07. The area ratio of isocyanurate / uretdione-bonded tetramer / isocyanurate trimer by liquid chromatography was 0.065. Thereafter, the amount of diisocyanate (DI) increased after storage of the polyisocyanate composition and the moisture stability were evaluated. The evaluation results are shown in Table 1.

(Example 2)
A four-necked flask equipped with a stirrer, thermometer, reflux condenser, nitrogen blowing tube, and dropping funnel was placed in a nitrogen atmosphere, charged with 6,000 g of HDI and 11.0 g of isobutanol, and the reactor temperature was 80 with stirring. Hold at 2 ° C. for 2 hours. Thereafter, 5.0 g of a solution obtained by diluting the isocyanuration catalyst trimethyl-2-methyl-2-hydroxyethylammonium hydroxide with isobutanol to 5% by mass is added to conduct an isocyanuration reaction, and the NCO content of the reaction solution is When it reached 45.5% by mass, phosphoric acid was added to stop the reaction. The uretdione dimer concentration increased by this reaction was 1.0 mass% or less. Thereafter, the temperature was raised to 160 ° C. at a temperature raising rate of 1.6 ° C./min, and held at 160 ° C. for 1 hour. Thereafter, the temperature was lowered to 40 ° C. at a rate of 1.5 ° C./min. This heating produced a uretdione group, a uretonimino group, and an isocyanurate / uretdione bond structure. The obtained reaction solution was filtered using a PTFE filter (trade name: T300A090C, manufactured by ADVANTEC) having a pore size of 3 μm. Using a thin film evaporator, it was purified twice under the conditions of 160 ° C. and 0.2 Torr, non-volatile content 99.5% by mass, viscosity 280 mPa · s (25 ° C.), NCO content 23.2% by mass, HDI monomer concentration A polyisocyanate composition P-2 having 0.11% by mass and a phosphorus concentration of 3 ppm was obtained. Subsequent measurement and evaluation were performed in the same manner as in Example 1. The evaluation results are shown in Table 1.

(Example 3)
The temperature increase rate and temperature decrease rate of the reaction solution after the isocyanuration reaction were changed to 2.2 ° C./min and 2.4 ° C./min, respectively. Other conditions were the same as in Example 1 to obtain a polyisocyanate composition P-3. Subsequent measurements and evaluations were performed in the same manner as in Example 1. The evaluation results are shown in Table 1.

Example 4
The heating condition of the reaction solution after the isocyanuration reaction was changed to 155 ° C. and 1.0 hour.
Other conditions were the same as in Example 1 to obtain a polyisocyanate composition P-4.
Subsequent measurements and evaluations were performed in the same manner as in Example 1. The evaluation results are shown in Table 1.

(Example 5)
The heating condition of the reaction solution after the isocyanuration reaction was changed to 165 ° C. and 5.0 hours. Other conditions were the same as in Example 1 to obtain a polyisocyanate composition P-5. Subsequent measurements and evaluations were performed in the same manner as in Example 1. The evaluation results are shown in Table 1.

(Comparative Example 1)
The temperature increase rate and temperature decrease rate of the reaction solution after the isocyanuration reaction were changed to 2.6 ° C./min and 4.5 ° C./min, respectively. Other conditions were the same as in Example 1 to obtain a polyisocyanate composition C-1. Subsequent measurements and evaluations were performed in the same manner as in Example 1. The evaluation results are shown in Table 2.

(Comparative Example 2)
After the isocyanuration reaction, the temperature was raised to 165 ° C. at a rate of temperature rise of 0.3 ° C./min, and held at 165 ° C. for 8 hours. Thereafter, the temperature was lowered to 40 ° C. at a rate of 0.3 ° C./min. Other conditions were the same as in Example 1 to obtain a polyisocyanate composition C-2. Subsequent measurements and evaluations were performed in the same manner as in Example 1. The evaluation results are shown in Table 2.

(Comparative Example 3)
A four-necked flask equipped with a stirrer, thermometer, reflux condenser, nitrogen blowing tube, and dropping funnel was placed in a nitrogen atmosphere, charged with 6,000 g of HDI and 7.0 g of isobutanol, and the reactor temperature was 80 with stirring. Hold at 2 ° C. for 2 hours. Thereafter, the isocyanurate conversion catalyst trimethyl-2-methyl-2-hydroxyethylammonium hydroxide was mixed with isobutanol. 5.0 g of a solution diluted to 0% by weight was added to carry out an isocyanuration reaction. When the NCO content of the reaction solution reached 44.1% by mass, phosphoric acid was added to stop the reaction. The uretdione dimer concentration increased by this reaction was 1.0 mass% or less. The reaction solution was further maintained at 100 ° C. for 1 hour. The obtained reaction solution was filtered using a PTFE filter (trade name: T300A090C, manufactured by ADVANTEC) having a pore size of 3 μm. Using a thin film evaporator, it was purified twice under the conditions of 160 ° C. and 0.2 Torr, non-volatile content 99.5% by mass, viscosity 1050 mPa · s (25 ° C.), NCO content 23.1% by mass, HDI monomer concentration Polyisocyanate composition C-3 having 0.09% by mass and a phosphorus concentration of 20 ppm was obtained. Subsequent measurements and evaluations were performed in the same manner as in Example 1. The evaluation results are shown in Table 2.

(Comparative Example 4)
A four-necked flask equipped with a stirrer, thermometer, reflux condenser, nitrogen blowing tube, and dropping funnel was placed in a nitrogen atmosphere, 6,000 g of HDI was charged, and the reactor internal temperature was maintained at 30 ° C. for 2 hours with stirring. . Thereafter, 14.8 g (0.1 mol) of 1-butylphosphorane was added and held for 15 hours. Thereafter, the reaction was stopped by adding 3.6 g (0.11 mol) of elemental sulfur. The obtained reaction solution was filtered using a PTFE filter (trade name: T300A090C, manufactured by ADVANTEC) having a pore size of 3 μm. Using a thin film evaporator, purified twice at 160 ° C. and 0.2 Torr, non-volatile content 99.5% by mass, viscosity 1000 mPa · s (25 ° C.), NCO content 23.3% by mass, HDI monomer concentration Polyisocyanate composition C-4 having 0.12% by mass and a phosphorus concentration of more than 100 ppm was obtained. Subsequent measurements and evaluations were performed in the same manner as in Example 1. The evaluation results are shown in Table 2.

(Comparative Example 5)
A four-necked flask equipped with a stirrer, a thermometer, and a nitrogen blowing tube was placed in a nitrogen atmosphere, 700 g of the polyisocyanate composition C-1 obtained in Comparative Example 1, and the polyisocyanate composition C-4 obtained in Comparative Example 5 300 g was charged and stirred at 40 ° C. for 2 hours to obtain a polyisocyanate composition C-5. Subsequent measurements and evaluations were performed in the same manner as in Example 1. The evaluation results are shown in Table 1.

(Example 6)
A four-necked flask equipped with a stirrer, a thermometer, and a nitrogen blowing tube was placed in a nitrogen atmosphere, 820 g of the polyisocyanate composition C-1 obtained in Comparative Example 1, and the polyisocyanate composition C-4 obtained in Comparative Example 4 180 g was charged and stirred at 40 ° C. for 2 hours to obtain a polyisocyanate composition P-6. Subsequent measurements and evaluations were performed in the same manner as in Example 1. The evaluation results are shown in Table 1.

(Comparative Example 6)
A four-necked flask equipped with a stirrer, thermometer, reflux condenser, nitrogen blowing tube, and dropping funnel is placed in a nitrogen atmosphere, charged with 6,000 g of HDI and 7.0 g of isobutanol, and the temperature inside the reactor under stirring is increased. Hold at 80 ° C. for 2 hours. Thereafter, 5.0 g of a solution obtained by diluting the isocyanuration catalyst trimethyl-2-methyl-2-hydroxyethylammonium hydroxide with isobutanol to 5% by mass is added to conduct an isocyanuration reaction, and the NCO content of the reaction solution is When it reached 44.6% by mass, phosphoric acid was added to stop the reaction. The uretdione dimer concentration increased by this reaction was 1.0 mass% or less. Thereafter, the temperature was raised to 160 ° C. at a temperature raising rate of 1.6 ° C./min, and held at 160 ° C. for 1 hour. Thereafter, the temperature was lowered to 40 ° C. at a rate of 1.5 ° C./min. This heating produced a uretdione group, a uretonimino group, and an isocyanurate / uretdione bond structure. Using a thin film evaporator, purification was performed twice at 160 ° C. and 0.2 Torr, non-volatile content 99.5% by mass, viscosity 520 mPa · s (25 ° C.), NCO content 23.1% by mass, HDI monomer concentration Polyisocyanate composition C-6 having 0.11% by mass and a phosphorus concentration of more than 100 ppm was obtained. Subsequent measurements and evaluations were performed in the same manner as in Example 1. The evaluation results are shown in Table 2.

(Comparative Example 7)
The reaction solution after the isocyanuration reaction was filtered using a PTFE filter (trade name: T010A090C, manufactured by ADVANTEC) having a pore size of 0.1 μm. The filtration took 10 times or more the time of Example 1. Other conditions were the same as in Example 1 to obtain a polyisocyanate composition C-7. Subsequent measurements and evaluations were performed in the same manner as in Example 1. The evaluation results are shown in Table 2.

Hereinafter, in Tables 1 and 2, “B / A molar ratio” indicates (uretdione group absorption × 1/2) / (isocyanurate group absorption × 1/3) calculated from an integrated value in ¹³ C-NMR. “C / A molar ratio” indicates (uretonimino group absorption) / (isocyanurate group absorption × 1/3) calculated from an integrated value in ¹³ C-NMR, and “D / A molar ratio” is ¹³ C-NMR. (Iminooxadiazinedione group absorption) / (isocyanurate group absorption × 1/3) calculated from the integrated value, and “E / A molar ratio” calculated from the integrated value in ¹³ C-NMR (allophanate group absorption) ) / (Isocyanurate group absorption × 1/3), and “F / A ratio” was calculated from the area ratio in liquid chromatography (isocyanurate / uretdione-bonded tetramer) / (isocyanate) Nurate trimer).

[Production of water-based paint composition]
(Example 7)
Aqueous acrylic polyol Setaqua 6515 (OH content 3.3%, non-volatile content 45%) 62.23 g was weighed into a container, and while stirring, 0.10 g of leveling agent BYK-348 (manufactured by BYK), Tego Wet 270 ( 0.10 g of Evonic Tego Chemie), 0.65 g of UV absorber Tinuvin 1130 (BASF), 0.32 g of light stabilizer Tinuvin 292 (BASF), 4.51 g of water, and 5 Stir for minutes. To this, 64 parts by weight of the polyisocyanate composition P-1 prepared in Example 1 was previously mixed with 36 parts by weight of butyl glycol acetate as a diluent solvent, and the molar ratio of isocyanate groups to hydroxyl groups was NCO / An aqueous coating composition was prepared by adding OH = 1.5 (22.7 g) and stirring for 10 minutes. The evaluation results of the mixing stability with the main agent are shown in Table 3. In addition, Table 3 shows the physical properties of the coating film after being applied to the substrate and dried.

(Examples 8-12, Comparative Examples 8-14)
A water-based coating composition was prepared in the same procedure as in Example 7. Tables 3 and 4 show the results of evaluation of the mixing stability with the main agent. Table 3 and Table 4 show the physical properties of the coating film after being applied to the substrate and dried.

  The polyisocyanate compositions of Examples 1 to 6 have a low viscosity and excellent storage stability and moisture stability. The aqueous coating compositions of Examples 7 to 12 have mixing stability with the main agent, gloss, and image clarity. It was confirmed to be excellent.

  The aqueous coating composition using the polyisocyanate composition according to the present invention as a curing agent can be used as a coating such as roll coating, curtain flow coating, spray coating, bell coating, electrostatic coating and the like. Moreover, it can also be used as a primer or top intermediate coating material for metals such as steel plates and surface-treated steel plates, and materials such as plastics, wood, films and inorganic materials. Furthermore, it is also useful as a paint for imparting heat resistance, cosmetic properties (surface smoothness, sharpness), etc. to pre-coated metals including rust-proof steel plates and automobile coatings. Furthermore, it is also useful as a urethane raw material for adhesives, pressure-sensitive adhesives, elastomers, foams, surface treatment agents and the like.

Claims (3)

Obtained from an aliphatic diisocyanate containing 1,6-diisocyanatohexane,
Containing an isocyanurate group, a uretdione group, a uretonimino group, and an iminooxadiazinedione group;
The molar ratio of the uretonimino group / the isocyanurate group is 0.0010 to 0.0050, the molar ratio of the iminooxadiazinedione group / the isocyanurate group is 0.00050 to 0.30, and
The phosphorus concentration in plasma emission spectroscopy is 1-50 ppm,
Polyisocyanate composition.   An aqueous coating composition comprising an aqueous acrylic polyol, a surface tension adjusting agent, and the polyisocyanate composition according to claim 1.   A coating film obtained by curing the water-based coating composition according to claim 2.