JP4707379B2 - Polyisocyanate composition - Google Patents

Description

  The present invention relates to a polyisocyanate composition having good weather resistance, low viscosity, and good drying properties.

  A urethane-based coating composition using polyisocyanate as a curing agent is widely used as a coating material for automobiles, interior / exterior of buildings, home appliances and the like because of its excellent chemical resistance and flexibility. Furthermore, a coating film obtained from a polyisocyanate derived from an aliphatic diisocyanate does not turn yellow and is excellent in weather resistance, so that it is often used. Among them, it is known that the isocyanurate type polyisocyanate disclosed in Patent Document 1 is particularly excellent in weather resistance. Currently, studies are being conducted to reduce volatile substances discharged into the atmosphere from the viewpoint of the global environment. There are three types of paints for reducing volatile substances: high solid paints, water-based paints, and powder paints. A high solid paint is a paint having a low volatile substance content and a high solid content compared to the current solvent-based paint. The water-based paint is a paint in which all or a part of volatile substances are replaced with water. The powder paint is a powder paint containing neither a volatile substance nor water. Among them, the high solid paint has the advantage that the existing equipment can be used and the physical properties of the paint film such as the appearance of the paint film used, which are the advantages of the current solvent-based paint, can be maintained. In the case of water-based paints, generally used coating films lack physical properties such as water resistance and drying properties, and further, capital investment is required. In the case of powder coating, there are problems such as poor coating appearance of the coating film used, difficulty in forming a thin film, and large-scale capital investment required.

Although the polyisocyanate of Patent Document 1 is currently widely used in solvent-based paints, there is a case where high solidification as currently desired in the market cannot be achieved due to insufficient viscosity reduction. . Therefore, a polyisocyanate composition having a lower viscosity that can maintain current physical properties such as drying properties and weather resistance for use in high solid paints has been eagerly desired.
Patent Document 2 discloses a system in which an allophanate group-containing polyisocyanate having a low viscosity and an isocyanurate type polyisocyanate are mixed. However, the allophanate group-containing polyisocyanate of this patent document is an allophanate-type polyisocyanate containing an alkyl chain whose terminal derived from a monoalcohol is not an isocyanate group, and may have insufficient drying properties.
JP 6-62913 JP 2003-55433 A

  An object of this invention is to provide the polyisocyanate composition which is favorable in weather resistance and drying property, and is low-viscosity, and a coating composition using the same.

  As a result of diligent research, the present inventor has found that a paint using a polyisocyanate composition obtained by mixing an isocyanurate type polyisocyanate and a polyisocyanate having a urethane bond at a specific ratio as a curing agent is a high solid and has a drying property. As a result, the present inventors have found a surprising result that the weather resistance of the coating film obtained from the film is good and good, and the present invention has been completed based on this finding.

That is, the present invention
1. A polyisocyanate composition having a viscosity of 1100 mPa · s / 25 ° C. or less obtained by mixing A and B below at 20:80 to 80:20 (mass ratio).

[1] The following polyisocyanate (A) derived from hexamethylene diisocyanate.
1) Isocyanurate trimer concentration of 60% by mass or more and pentamer concentration of 21% by mass or less.
[2] A polyisocyanate (B) which is a compound derived from hexamethylene diisocyanate and a diol and which satisfies the following conditions 1) to 3) having a urethane bond.
1) Urethane bond moles Urethane bond ratio = ―――――――――――――――――――――― ≧ 0.25
Number of moles of urethane bond + number of moles of allophanate bond 2) Number average molecular weight: 400 to 700
3) Average number of isocyanate groups: 2.0 to 3.5
2. 1 above. A coating composition comprising the polyisocyanate composition described.
3. 1 above. A high solids coating composition comprising the polyisocyanate composition described.
It is about.

  A coating composition using the polyisocyanate composition of the present invention as a curing agent is used as a curing agent for high solid coatings because of good weather resistance and drying property and low viscosity.

The present invention is described in detail below. It is a polyisocyanate composition having a viscosity of 1100 m · Pas / 25 ° C. or less obtained by mixing A and B below at 20:80 to 80:20 (mass ratio).
1. The following polyisocyanate (A) derived from hexamethylene diisocyanate.
1) Isocyanurate trimer concentration of 60% by mass or more and pentamer concentration of 21% by mass or less.
2. A polyisocyanate (B) which is a compound derived from hexamethylene diisocyanate and a diol and which satisfies the following conditions 1) to 3) having a urethane bond.
1) Urethane bond moles Urethane bond ratio = ―――――――――――――――――――――― ≧ 0.25
Number of moles of urethane bond + number of moles of allophanate bond 2) Number average molecular weight: 400 to 700
3) Average number of isocyanate groups: 2.0 to 3.5

  The polyisocyanate A used in the present invention has an isocyanurate trimer concentration derived from hexamethylene diisocyanate (hereinafter referred to as HDI) of 60% by mass or more and a pentamer concentration of 21% by mass or less. Preferably, the isocyanurate trimer concentration is 63% by mass or more, and more preferably, the isocyanurate trimer concentration is 66% by mass or more.

When the isocyanurate trimer concentration is less than 60% by mass, or when the pentamer concentration exceeds 21% by mass, the viscosity of the polyisocyanate may become too high. These isocyanurate trimer and pentamer concentrations were measured by gel permeation chromatography (hereinafter referred to as GPC) measurement, and the area ratio of each peak of GPC was defined as mass%.
Equipment: Tosoh Corporation HLC-802A
Column: Tosoh Corporation G1000HXL x 1
G2000HXL x 1
G3000HXL x 1 Carrier: Tetrahydrofuran Detection method: Differential refractometer

A method for producing the polyisocyanate A of the present invention will be described. Polyisocyanate A is a polyisocyanate having an isocyanurate bond.
Examples of the catalyst for producing a polyisocyanate having an isocyanurate bond include generally used isocyanurate-forming catalysts.

As the isocyanuration catalyst, for example, a catalyst having basicity is generally preferable, for example, tetraalkylammonium hydroxide such as tetramethylammonium and tetraethylammonium, and weak organic acid salts such as acetic acid and capric acid, and 2 such as trimethyl. Hydroxypropylammonium hydroxide such as hydroxypropylammonium, trimethylhydroxyethylammonium, triethylhydroxypropylammonium, triethylhydroxyethylammonium, etc., organic weak acid salts such as acetic acid and capric acid, 3, acetic acid, caproic acid, octylic acid, myristic acid Alkali metal salts of alkyl carboxylic acids such as tin, zinc and lead, etc., 4 metal alcoholates such as sodium and potassium, 5 such as hexa Aminosilyl group-containing compounds such Chirujishirazan, 6, Mannich bases, 7, in combination with tertiary amines with epoxy compounds, 8, for example, a phosphorus-based compounds such as tributyl phosphine. After the completion of the reaction, these are inactivated by, for example, acidic substances such as phosphoric acid and acidic phosphoric acid esters that neutralize the catalyst, thermal decomposition, and chemical decomposition.
The reaction is selected from a range of yield of 10 to 70% by mass. The viscosity of the polyisocyanate composition obtained in high yield is high. After the reaction is completed, unreacted diisocyanate is removed by extraction using a thin film evaporator.

The polyisocyanate B used in the present invention is a compound derived from hexamethylene diisocyanate and a diol, has a urethane bond, and a urethane bond ratio represented by the following formula (1) is 0.25 or more, The number average molecular weight is 400 to 700, and the average number of isocyanate groups is 2.0 to 3.5.

Urethane bond mole number Urethane bond ratio = ―――――――――――――――――――――― (1)
Urethane bond moles + allophanate bond moles

The number of moles of urethane bonds and the number of moles of allophanate bonds for determining the urethane bond ratio are determined by ¹ H-NMR measurement. Moreover, when the urethane bond ratio of polyisocyanate B is less than 0.25, the viscosity is generally too high, which is not preferable. Preferably, it is the range of 0.4-0.9, More preferably, it is the range of 0.5-0.75.

When there is a bond other than the above, for example, a urea bond or a burette bond, the weather resistance may be deteriorated, which is not preferable. Polyisocyanates containing urethane bonds or allophanate bonds derived from hexamethylene diisocyanate and monoalcohol are not preferred because the average number of isocyanate groups is less than 2.0, and the crosslinking and drying properties are poor.
The number average molecular weight is 400 to 700 as determined by GPC measurement based on polystyrene described below. It is preferable that it is 400-600, More preferably, it is 400-550. When the number average molecular weight is less than 400, the volatility is generally high. When the number average molecular weight is 700 or more, the viscosity may be too high. Furthermore, the average number of isocyanate groups of polyisocyanate B is 2.0 to 3.5, preferably 2.1 to 3.5, and more preferably 2.3 to 3.5. When the average number of isocyanate groups is less than 2.0, the crosslinkability and drying properties may decrease, and when it exceeds 3.5, the viscosity may increase.

The average number of isosocyanate groups is obtained by the following formula (2).

(Number average molecular weight) x (Isocyanate group mass%)
――――――――――――――――――――― = Average number of isocyanate groups (2)
Formula weight of isocyanate (42)

Polyisocyanate B has a urethane bond, an allophanate bond, and the like.
For the production of polyisocyanate B, it is preferable to carry out a urethanization reaction and an allophanatization reaction, which may be carried out simultaneously or independently. Specific examples of the polyisocyanate to be obtained include those obtained by reacting hexamethylene diisocyanate and diol, urethanized products, partially allophanatized urethanized products, or mixtures of urethanized products and allophanated products. Polyisocyanate B may be used in combination of two or more polyisocyanates. The starting diol of polyisocyanate B used in the present invention may be used alone or in combination of two or more.

  The raw material diol is a compound having two hydroxyl groups in one molecule. For example, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,3-butane Diol, 1,2-butanediol, 1,5-pentanediol, 1,6-hexanediol, methylpentanediol, cyclohexanedimethanol, methylpentanediol, mepentylglycol, hydrogenated bisphenol A, diethylene glycol, triethylene glycol, etc. Is mentioned. In addition, a derivative of hexamethylene diisocyanate and a polyol having three or more hydroxyl groups is not preferable because the viscosity becomes too high.

Polyisocyanate B has a urethane bond, an allophanate bond, and the like.
The urethanization reaction may or may not use a catalyst. Examples of the catalyst when used include organic metal salts such as tin, zinc and lead, and tertiary amines.
In addition, the allophanatization reaction may be performed with or without a catalyst. As a catalyst when used, lead, zinc, tin, zirconium, diliconyl, bismuth, calcium, magnesium, lithium and other carboxylates, chlorides, Examples include bromide and iodide. Moreover, when a reaction catalyst is used, it is preferable to deactivate a catalyst after completion | finish of reaction.

These reactions may or may not use a solvent. If a solvent is used, a solvent inert to the isocyanate group should be used. The reaction temperature is usually 20 to 160 ° C, preferably 40 to 130 ° C.
After completion of the reaction, unreacted diisocyanate is removed by a thin film evaporator, extraction or the like.
The concentration of the HDI monomer in the polyisocyanates A and B is 3% by mass or less, preferably 1% by mass or less, and more preferably 0.5% by mass or less. When the HDI monomer concentration exceeds 3% by mass, the curability of the polyisocyanate composition may be lowered.

The mixing ratio of polyisocyanate A and B is 20:80 to 80:20. This mixing ratio is preferably 20:80 to 70:30, and more preferably 20:80 to 60:40.
When the polyisocyanate B is less than 20% by mass, the viscosity of the curing agent may be too high, and when it exceeds 80% by mass, the weather resistance of the cured coating film may be inferior.

The viscosity of the polyisocyanate composition is 1100 mPa · s / 25 ° C. or less, preferably 1000 mPa · s / 25 ° C. or less, more preferably 900 mPa · s / 25 ° C. or less.
When the viscosity is higher than 1100 mPa · s / 25 ° C., the solid content of the paint is lowered, and it cannot be a curing agent for high solid paint.

  The polyisocyanate composition of the present invention is mixed with a compound having two or more active hydrogens having reactivity with isocyanate groups in the molecule, and constitutes the main component of the coating composition. The polyisocyanate composition can react with the active hydrogen-containing compound to form a crosslinked coating. Examples of the compound having two or more active hydrogens include polyols, polyamines, and polythiols. In many cases, polyols are used. Examples of this polyol include polyester polyol, polyether polyol, acrylic polyol, polyolefin polyol, and fluorine polyol.

  As the polyester polyol, 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, or a mixture thereof Polyester polyol obtained by a condensation reaction with a single or mixture of polyhydric alcohols selected from the group of ethylene glycol, propylene glycol, diethylene glycol, neopentyl glycol, trimethylolpropane, glycerin and the like, and for example, ε-caprolactone and polyhydric alcohol And polycaprolactones obtained by ring-opening polymerization using These polyester polyols can be modified with aromatic diisocyanates, aliphatic and alicyclic diisocyanates and polyisocyanates obtained therefrom. In this case, aliphatic and alicyclic diisocyanates and the resulting polyisocyanates are particularly preferred from the viewpoint of weather resistance, yellowing resistance and the like.

  Examples of the polyether polyol include a polybasic hydroxy compound alone or in a mixture thereof, for example, a hydroxide such as lithium, sodium and potassium, a strongly basic catalyst such as alcoholate and alkylamine, a metal porphyrin, a hexacyanocobaltate zinc complex and the like. Polyethers obtained by random or block addition of alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, cyclohexene oxide, styrene oxide, etc., alone or in mixture to polyvalent hydroxy compounds Polyether polyols obtained by reacting alkylene oxides with polyols and further polyamine compounds such as ethylenediamines, and these polyethers as a medium. Obtained by polymerizing Ruamido like include so-called polymer polyols and the like.

Examples of the polyvalent hydroxy compound include 1 to 6 below, such as diglycerin, ditrimethylolpropane, pentaerythritol, dipentaerythritol and the like 2, such as erythritol, D-threitol, L-arabinitol, ribitol, xylitol, Sugar alcohol compounds 3 such as sorbitol, mannitol, galactitol, rhamnitol, for example, saccharides such as arabinose, ribose, xylose, glucose, mannose, galactose, fructose, sorbose, rhamnose, fucose, ribodesource,
4, disaccharides such as trehalose, sucrose, maltose, cellobiose, gentiobiose, lactose, melibiose,
5. For example, there are trisaccharides 6 such as raffinose, gentianose, and meletitose, for example, tetrasaccharides such as stachyose.

  Examples of the acrylic polyol include acrylic acid esters having active hydrogen such as 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, and 2-hydroxybutyl acrylate, or glycerol monoester or methacrylic acid Monoester, trimethylolpropane acrylic acid monoester or methacrylic acid monoester alone or in mixture and methyl acrylate, ethyl acrylate, isopropyl acrylate, acrylic acid-n-butyl, acrylic acid-2- Acrylic esters such as ethylhexyl, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-hydroxybutyl methacrylate, 3-hydroxypropyl methacrylate, methacrylic acid-4 Methacrylic acid ester having active hydrogen such as hydroxybutyl, or methacrylic acid such as methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, methacrylate-n-butyl, isobutyl methacrylate, methacrylate-n-hexyl, lauryl methacrylate A single or mixture selected from the group of esters, unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, itaconic acid, unsaturated amides such as acrylamide, N-methylol acrylamide, diacetone acrylamide, and methacrylic acid Acrylates obtained by polymerization in the presence or absence of a single or mixture selected from the group of other polymerizable monomers such as glycidyl, styrene, vinyl toluene, vinyl acetate, acrylonitrile, dibutyl fumarate and the like. Polyols.

Examples of the polyolefin polyol include polybutadiene having two or more hydroxyl groups, hydrogenated polybutadiene, polyisoprene, and hydrogenated polyisoprene.
Examples of preferred polyols are the above-mentioned low molecular weight polyols and polycaprolactone polyols obtained by ring-opening polymerization of ε-caprolactone to this low molecular weight.
The fluorine polyol is a polyol containing fluorine in the molecule. For example, fluoroolefin, cyclovinyl ether, hydroxyalkyl vinyl ether, vinyl monocarboxylate disclosed in JP-A-57-34107 and JP-A-61-275111. There are copolymers such as esters. The hydroxyl value of the polyol is selected from 30 to 200 mgKOH / g and the acid value of 0 to 30 mgKOH / g.
Preferred polyols are acrylic polyols and polyester polyols. If necessary, a melamine type curing agent such as a complete alkyl type, a methylol group type alkyl, an imino group type alkyl or the like can be added.

Moreover, various solvents and additives can be used according to the application and purpose. Solvents include, for example, ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, esters such as ethyl acetate, n-butyl acetate, and cellosolve, and alcohols such as butanol and isopropyl alcohol. It can be appropriately selected and used accordingly. These solvents may be used alone or in combination of two or more.
Where necessary, antioxidants such as hindered phenols, ultraviolet absorbers such as benzotriazole and benzophenone, pigments such as titanium oxide, carbon black, indigo, quinacridone, pearl mica, metal powder pigments such as aluminum, etc. Rheology control agents such as hydroxyethyl cellulose, urea compounds, microgels and the like may be added.

  The coating composition prepared in this way can be used as a primer or upper medium for materials such as steel, surface-treated steel and other metals and plastics, and inorganic materials by roll coating, curtain flow coating, spray coating, electrostatic coating, bell coating, etc. As a coating, it is useful for imparting cosmetic properties, weather resistance, acid resistance, rust resistance, chipping resistance, etc. to pre-coated metals including rust-proof steel sheets and automobile coating. It is also useful as a urethane raw material for adhesives, pressure-sensitive adhesives, elastomers, foams, surface treatment agents and the like.

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to the following examples. All parts are parts by mass.
(Measurement of number average molecular weight)
The number average molecular weight is a polystyrene-based number average molecular weight by GPC measurement using the following apparatus.
Equipment: Tosoh Corporation HLC-802A
Column: Tosoh Corporation G1000HXL x 1
G2000HXL x 1
G3000HXL x 1 Carrier: Tetrahydrofuran Detection method: Differential refractometer (Calculation method of average number of isocyanate groups)

(Number average molecular weight) x (Isocyanate group mass%)
―――――――――――――――――――――― ＝ Average number of isocyanate groups
Formula weight of isocyanate (42)
(Measurement of viscosity)

It measured at 25 degreeC using the E-type viscosity meter (VISICONIC ED type | mold by Tokimec).

Production Example 1 (Polyisocyanate A1)
The inside of a four-necked flask equipped with a stirrer, thermometer and condenser was replaced with nitrogen, charged with 1000 g of HDI: 300 g and xylene: 0.3 g of tetramethylammonium capryate was added as a catalyst while stirring at 60 ° C. It was. Four hours later, when the addition ratio of HDI to isocyanurate reached 21% by refractive index measurement, 0.2 g of phosphoric acid was added to stop the reaction. Then, after filtering a reaction liquid, xylene and unreacted HDI were removed with the thin film distillation apparatus. The polyisocyanate obtained is designated as A1. The physical properties of the resulting polyisocyanate A1 were as follows. Viscosity 1350 mPa · s / 25 ° C., isocyanurate trimer concentration 68 mass%, pentamer concentration 20 mass%

Production Example 2 (Polyisocyanate B1)
The inside of a four-necked flask equipped with a stirrer, thermometer, and condenser was replaced with nitrogen, charged with HDI: 1250 g and 1,3-butanediol: 90.0 g, and reacted at 160 ° C. for 1 hour with stirring. . Thereafter, unreacted HDI was removed by a thin film distillation apparatus. The resulting polyisocyanate is designated B1. The physical properties of the resulting polyisocyanate B1 were as follows.
Viscosity 600 mPa · s / 25 ° C., urethane bond ratio 0.85, number average molecular weight 490, isocyanate group average number 2.3

Production Example 3 (Polyisocyanate B2)
The inside of a four-necked flask equipped with a stirrer, a thermometer, and a cooling tube was purged with nitrogen, charged with HDI: 862 g and n-butanol: 38.0 g, and subjected to urethanization reaction at 90 ° C. for 1 hour with stirring. At 130 ° C., 0.30 g of a solid 20% mineral spirit solution of zirconyl 2-ethylhexanoate as an allophanatization catalyst was added. 30 minutes later, when the refractive index increase of the reaction solution reached 0.0055, 0.56 g of a solid 39% ethanol solution of pyrophosphate was added to stop the reaction. Thereafter, unreacted HDI was removed by a thin film distillation apparatus. The resulting polyisocyanate is designated B2. The physical properties of the resulting polyisocyanate B2 were as follows. Viscosity 120 mPa · s / 25 ° C., urethane bond ratio 0, number average molecular weight 410, isocyanate group average number 2.0

(High solidification evaluation)
Polyisocyanate composition and polyester polyol (trade name Setal 166 manufactured by Akzo Novel Resin bv: hydroxyl value 190 mgKOH / g (per resin), acid value 2.1 mgKOH / g> (per resin), solid content 80%) / Mixed so that the equivalent ratio of hydroxyl group is 1.0 and ethyl acetate / toluene / butyl acetate / xylene / propylene glycol monomethyl as a thinner so that the viscosity measured with Ford Cup No. 4 is 20 seconds. Add a mixture of ether acetate (mass ratio 30/30/20/15/5) to adjust.
The case where the solid content of the paint at the time of adjustment with the above composition was 60% or more was marked with ◯, and the case where it was 60% or less was marked with x. The results are shown in Table 1.

(Weather resistance evaluation)
A polyisocyanate composition and a polyester polyol (trade name Setal166, manufactured by Akzo Novel Resin bv) were blended so that the equivalent ratio of isocyanate group / hydroxyl group was 1.0, and the solid content mass of polyisocyanate and acrylic polyol was 50. As a thinner, a mixed solution of ethyl acetate / toluene / butyl acetate / xylene / propylene glycol monomethyl ether acetate (mass ratio 30/30/20/15/5) was added thereto to obtain a coating solution. The paint solution was dried on a white enameled plate and then coated with an applicator so as to have a film thickness of 40 μm. After curing the coating film at 20 ° C. and a humidity of 63% for 1 week, the weather resistance of the coated plate was evaluated.

Dew panel weather meter (made by Suga Test Instruments) was used for the weather resistance evaluation.
Evaluation conditions were in accordance with JIS D0205, irradiation illuminance of 30 W / m ² , panel temperature of 60 ° C., irradiation time and dew condensation time were cycled every 4 hours. When the exposure time was 1200 hours, the gloss retention was 80% or more, and ○ was less than 80%. The results are shown in Table 1.

(Evaluation of dryness of coating film)
Further, the coating solution prepared as described above was applied to an applicator so as to have a film thickness of 40 μm after drying on a glass plate, and a coating film drying test was conducted by finger touch after 24 hours under the conditions of 20 ° C. and humidity of 63%. The case where there was no tack was rated as ◯, and the case where tack remained was marked as x. The results are shown in Table 1.

"Example 1"
Polyisocyanate A1 (viscosity 1350 mPa · s / 25 ° C., isocyanurate trimer concentration 68% by mass, pentamer concentration 20% by mass) and polyisocyanate B 1 (viscosity 600 mPa · s / 25 ° C., urethane bond ratio 0.85, A number average molecular weight of 490 and an isocyanate functional group number of 2.3) were mixed at a mass ratio of 50:50. The resulting polyisocyanate mixture had a viscosity of 850 mPa · s / 25 ° C.

"Examples 2-3, Comparative Examples 1-3"
Hereinafter, also about Examples 2-3 and Comparative Examples 1-3, it mixed by the composition of the following Table 1, and obtained the polyisocyanate composition. The polyisocyanate composition was used to evaluate each of high solidification, weather resistance, and coating film drying property. In the present invention, there was a correlation between low viscosity and high solidification, but there was no relationship between low viscosity and drying properties. Dryability is attributed to the structure of the polyisocyanate. When the following polyisocyanates are compared individually, the dryness is good A1>B1> B2. Therefore, when it was made into a mixture, the results shown in Table 1 below were obtained.

  The composition of the present invention can be suitably used in the field of paints, particularly in the field of high solid paints.

Claims (3)

A polyisocyanate composition having a viscosity of 1100 mPa · s / 25 ° C. or less obtained by mixing A and B below at a ratio of 20:80 to 80:20 (mass ratio).
1. The following polyisocyanate (A) derived from hexamethylene diisocyanate
1) Isocyanurate trimer concentration of 60% by mass or more and pentamer concentration of 21% by mass or less.
2. A polyisocyanate (B) derived from hexamethylene diisocyanate and a diol, which has a urethane bond and satisfies the following conditions 1) to 3)
1) Urethane bond ratio:
Urethane bond moles / (urethane bond moles + allophanate bond moles) =
0.4-0.9
2) Number average molecular weight: 400-700
3) Average number of isocyanate groups: 2.3 to 3.5   A coating composition comprising the polyisocyanate composition of claim 1.   A high solids coating composition comprising the polyisocyanate composition of claim 1.