JP5136964B2 - Modified polyisocyanate composition and two-component polyurethane coating composition using the same - Google Patents

Description

  The present invention particularly relates to a modified polyisocyanate composition excellent in solvent solubility (hereinafter referred to as tolerance) and weather resistance in a low-polar organic solvent, and a two-component polyurethane coating agent composition using the same. In the present specification, the “low polarity organic solvent” refers to an organic solvent having an aniline point of 10 to 70 ° C. or a mixed aniline point of 5 to 50 ° C.

  In the paint / coating and adhesive fields, 1,6-hexamethylene diisocyanate (hereinafter referred to as HDI), isophorone diisocyanate (hereinafter referred to as IPDI) and the like, non-yellowing derived from alicyclic diisocyanates and aliphatic diisocyanates. Although the modified polyisocyanate is excellent in weather resistance, among them, the polyisocyanate type containing an isocyanurate bond has high chemical and thermal stability, and particularly excellent in weather resistance, heat resistance, and durability. It is widely used according to its application, and further application development is expected in the future.

This type containing an isocyanurate bond has better tolerance than biuret type and urethane type and dissolves in aromatic hydrocarbon solvents such as toluene and xylene, but ordinary solvents such as toluene and xylene attack plastics. Since it has such a strong solubility, there are practical restrictions in terms of solvent selectivity, such as inability to repeat the coating until the base is cured in the coating process.
As a method for solving these problems of the prior art, for example, Patent Document 1 discloses A) an allophanate-modified polyisocyanate having an isocyanurate group of 25 mol% or less obtained from an aliphatic diisocyanate and a specific diol; ) Improve tolerance to low polar organic solvents by using a mixture of allophanate-modified polyisocyanate obtained from alicyclic diisocyanate and specific diol with an isocyanurate group of 25 mol% or less. A technique for obtaining a coating film having a high hardness has been proposed.
Furthermore, there is a movement to use odorless solvents such as paraffinic hydrocarbons in the future, but a curing agent with good solubility has not been obtained.

  When the diisocyanate is modified with a diol as in the technique proposed in Patent Document 1, the molecular weight of the resulting modified polyisocyanate increases, resulting in an increase in viscosity, and a low polar organic solvent, particularly a solubility in the solvent. It is not preferable because the tolerance is lowered with respect to organic solvents having no aniline point, mixed aniline point, and odorless solvents.

The technique disclosed in Patent Document 1 is aimed only at improving tolerance against low-polar organic solvents, and attempts to improve tolerance by using various modifiers. The hardness and drying properties when used as an adhesive composition tend to be inferior to those of existing curing agents that are easily dissolved in ordinary polar solvents, and have not been a technique that takes hardness and drying properties into consideration.
In other words, a hardener that has high tolerance to low polar organic solvents, especially organic solvents with insoluble aniline points or high mixed aniline points, and odorless solvents, and excellent hardness and drying properties can be obtained. The current situation is not.
In the paint and adhesive fields, a decrease in hardness leads to a decrease in physical properties, and a decrease in dryness leads to a decrease in workability, which is generally not preferred as a disadvantage.
JP 2006-52265 A

  An object of the present invention is to provide a modified polyisocyanate composition having a low potency and a long pot life, which is excellent in tolerance and weather resistance while ensuring excellent curability, drying property and stain resistance, and It is to provide a two-component polyurethane coating composition using

Therefore, the present inventors have made extensive studies and worked on the development of a modified polyisocyanate composition that dissolves in a low-polar organic solvent, and "low viscosity", "long pot life" and "excellent hardness, drying property, As a result of earnest research to simultaneously achieve "improved tolerance" and "high weather resistance" for these organic solvents, while ensuring "contamination resistance" as a result of the conventional technology, a specific hydrocarbon group has The present inventors have found that the above-mentioned problems can be solved by the combination of mainly allophanate-modified aliphatic polyisocyanate introduced in 1 and mainly isocyanurate-modified alicyclic polyisocyanate, and the present invention has been completed.
That is, this invention is shown to (1)-(6).

(1) A modified polyisocyanate composition having a viscosity of 2000 mPa · s (25 ° C.) or less, comprising the following (A) and (B):
(A) A modified aliphatic polyisocyanate having an allophanate group / isocyanurate group (molar ratio) of 100/0 to 90/10, obtained from an aliphatic diisocyanate and a monool having 3 to 20 carbon atoms.
(B) Modified alicyclic polyisocyanate having an allophanate group / isocyanurate group (molar ratio) of 0/100 to 5/95.
(2) A modified polyisocyanate composition having a viscosity of 2000 mPa · s (25 ° C.) or less and an isocyanate content of 10 to 20% by mass, comprising the following (A) and (B):
(A) A modified aliphatic polyisocyanate having an allophanate group / isocyanurate group (molar ratio) of 100/0 to 90/10, obtained from an aliphatic diisocyanate and a monool having 3 to 20 carbon atoms.
(B) Modified alicyclic polyisocyanate having an allophanate group / isocyanurate group (molar ratio) of 0/100 to 5/95.
(3) The modified polyisocyanate composition according to (1) or (2), wherein (A) / (B) (mass ratio) is 90/10 to 70/30.
(4) The modified polyisocyanate composition according to any one of (1) to (3), further containing a low-polar organic solvent.
(5) A two-component polyurethane coating composition comprising a polyol having a hydroxyl value of 1 to 300 mgKOH / g and the modified polyisocyanate composition according to any one of (1) to (4).
(6) A polyol having a hydroxyl value of 1 to 300 mg KOH / g dissolved or dispersed in a low polarity organic solvent and the modified polyisocyanate composition according to any one of (1) to (4), Liquid polyurethane coating composition.

The modified polyisocyanate composition of the present invention has a long pot life with a low viscosity with excellent tolerance and low weather resistance as well as excellent curability, drying property and stain resistance (polyurethane coating agent). It can be used as a curing agent (such as a composition). Therefore, it can be applied to a wide range of objects such as metal, plastic, concrete, and wood with good workability. Compared to the case where a conventional polar solvent is used, it does not cause lifting of the coating film when it is applied over or repaired on a coating film that is easily affected by the polar solvent. It has become possible to provide a two-component polyurethane coating composition that can be obtained.

The present invention is described in detail below.
Examples of the aliphatic diisocyanate used for synthesizing the (A) modified aliphatic polyisocyanate in the present invention include HDI, 1,4-tetramethylene diisocyanate, and lysine diisocyanate. These can be used alone or in admixture of two or more.
Of these aliphatic diisocyanates, HDI is preferred in consideration of weather resistance and the like.

The monoalcohol used for synthesizing the (A) modified aliphatic polyisocyanate in the present invention is one having 3 to 20 carbon atoms in order to further increase the tolerance against the low polar organic solvent. When the number of carbon atoms of monoalcohol exceeds 20, the isocyanate content of the modified aliphatic polyisocyanate (hereinafter referred to as NCO content) decreases, or, for example, in the case of stearyl alcohol, it tends to solidify at a low temperature. In the case of ethanol or methanol having 2 or less carbon atoms, tolerance to the solvent is lowered.
Specific examples of monoalcohol include n-propanol, iso-propanol, n-butanol, iso-butanol, n-pentanol, iso-pentanol, n-hexanol, n-heptanol, n-octanol, and 2-ethylhexanol. , Ethyldimethyl-1-hexanol, methyl-1-nonanol, dimethyl-1-octanol, tetramethyl-1-hexanol, 3-ethyl-4,5,6-trimethyloctanol, 4,5,6,7-tetramethyl Nonanol, 4,5,8-trimethyldecanol, 4,7,8-trimethyltridecanol, tridecanol, tetradecanol, 2-hexyldodecanol, 2-octyldodecanol, 2-decyltetradecanol, 2 -Hexadecyl octadecanol etc. are mentioned. These can be used alone or in admixture of two or more.

The amount of monoalcohol used may be equal to or less than the equivalent of the isocyanate group of the aliphatic diisocyanate. In other words, it is sufficient that the aliphatic diisocyanate is excessive, and it is preferable that the unreacted aliphatic diisocyanate is removed by thin film distillation or the like.
The optimum usage amount may be determined experimentally as appropriate. If the amount of monoalcohol is small, the yield per volume of the reaction vessel is poor and inefficient, and if the amount of monoalcohol is large, the polyallophanate increases, resulting in an increase in viscosity.
The urethanization reaction can be suitably performed in the range of 20 to 120 ° C.

In the synthesis of (A) the modified aliphatic polyisocyanate in the present invention, the allophanatization reaction can be performed using a known allophanate catalyst.
Preferred examples of the allophanatization catalyst include a metal salt of a carboxylic acid or a mixed catalyst of this and a phosphite, and more preferably a metal salt of a carboxylic acid.
Examples of the carboxylic acid that is a raw material for the metal salt of the carboxylic acid include saturated fats such as acetic acid, propionic acid, butyric acid, caproic acid, octylic acid, lauric acid, myristic acid, palmitic acid, stearic acid, and 2-ethylhexanoic acid. Of saturated monocyclic carboxylic acids such as aromatic carboxylic acids, cyclohexane carboxylic acids and cyclopentane carboxylic acids, saturated heterocarboxylic acids such as bicyclo (4.4.0) decane-2-carboxylic acid, and carboxylic acids such as naphthenic acid. Mixtures, unsaturated aliphatic carboxylic acids such as oleic acid, linoleic acid, linolenic acid, soybean oil fatty acid, tall oil fatty acid, aromatic aliphatic carboxylic acids such as diphenylacetic acid, and aromatic carboxylic acids such as benzoic acid and toluic acid It is done.
Examples of the metal that is a raw material for the metal salt of carboxylic acid include alkaline earth metals such as magnesium, calcium, and barium, transition metals such as manganese, iron, cobalt, nickel, copper, zinc, and zirconium, and aluminum. Examples include carbon group metals such as boron group, tin and lead.
These metal salts of carboxylic acids can be used alone or in admixture of two or more.
Of these, one or more selected from the group consisting of zirconium salts, tin salts, zinc salts and lead salts of saturated aliphatic carboxylic acids are preferred.

Phosphites used as cocatalysts include phosphite diesters and phosphite triesters.
Specific examples of phosphorous acid triesters include monophosphites such as triethyl phosphite and tributyl phosphite. Moreover, di, tri, or tetraphosphites derived from polyhydric alcohols such as distearyl pentaerythrityl diphosphite and ditridecylpentaerythritol diphosphite are also included. Further, diphosphites derived from bisphenol compounds such as dialkyl bisphenol A diphosphite having 1 to 20 carbon atoms, 4,4′-butylidene-bis (3-methyl-6-tert-butylphenyl-ditridecyl) phosphite, Polyphosphites such as hydrogenated bisphenol A phosphite polymer (molecular weight 2400-3000) and tris (2,3-dichloropropyl) phosphite are also mentioned.
Specific examples of phosphorous acid diesters include dilauryl hydrogen phosphite and diphenyl hydrogen phosphite.
These phosphites can be used alone or in admixture of two or more.
When a metal salt of carboxylic acid and a phosphite are used in combination, the amount of the metal salt of carboxylic acid itself may be less than when it is used alone. The amount of the metal salt of the carboxylic acid varies depending on the type, but usually 0.0005 to 1% by mass is preferable with respect to the reaction product of the monoalcohol and the aliphatic diisocyanate, and 0.001 to 0.1% by mass. Is more preferable. When the amount of the metal salt of the carboxylic acid is less than 0.0005% by mass relative to the reaction product, the reaction is substantially slow and takes a long time. On the other hand, the amount of the metal salt of the carboxylic acid is 1% by mass. If it exceeds%, reaction control is difficult, and problems such as shortening of the pot life of the two-component polyurethane coating composition containing the reaction product as a curing agent may occur.
The amount of phosphite used is preferably 0.005 to 1% by mass, more preferably 0.01 to 0.1% by mass, based on the reaction product of monoalcohol and aliphatic diisocyanate. When the amount used is less than 0.005% by mass, the effect as a co-catalyst is not sufficient. On the other hand, when the amount used exceeds 1% by mass, the final product using the product obtained by the reaction is used. May adversely affect physical properties.

The allophanate conversion rate is preferably such that the isocyanate group is consumed with respect to the hydroxyl group of the monoalcohol within a range where the allophanate group / isocyanurate group (molar ratio) is 100/0 to 90/10. When the allophanatization rate is outside this range, the physical properties of the coating film are deteriorated and turbidity is likely to occur.
The allophanatization reaction is preferably performed in the range of 70 to 150 ° C. If the reaction temperature is less than 70 ° C., the reaction proceeds very slowly, and if it exceeds 150 ° C., it tends to be colored.

  After reaching the desired allophanatization reaction rate, an allophanate reaction is stopped by adding a terminator such as acidic phosphoric acid ester, phosphoric acid or methyl paratoluenesulfonate.

The free unreacted aliphatic diisocyanate (monomer) present in the allophanatization reaction mixture is suitable, for example, by extraction with n-hexane or thin-film distillation at 120-140 ° C. under high vacuum of 10-100 Pa. It is preferable to remove the residual content to 1.0% by mass or less by means.

In order to synthesize the (B) modified alicyclic polyisocyanate in the present invention, alicyclic diisocyanates such as IPDI, hydrogenated toluene diisocyanate, hydrogenated xylene diisocyanate, hydrogenated diphenylmethane diisocyanate, and hydrogenated tetramethylxylene diisocyanate are suitable. Can be used for These can be used alone or in admixture of two or more.
Of these, IPDI is preferred when tolerance is considered.

In the synthesis of (B) the modified alicyclic polyisocyanate in the present invention, the isocyanuration reaction can be performed using a known isocyanuration catalyst.
Specific examples of the isocyanuration catalyst include triethylamine, N-ethylpiperidine, N, N′-dimethylpiperazine, N-ethylmorpholine, tertiary amines such as a Mannich base of a phenol compound, tetramethylammonium, tetraethylammonium, Tetraalkylammonium hydroxide and organic weak acid salts such as tetrabutylammonium, hydroxyalkylammonium hydroxide and organic weak acid salts such as trimethylhydroxypropylammonium, trimethylhydroxypropylammonium and triethylhydroxyethylammonium, acetic acid, propionic acid, butyric acid, Examples thereof include alkali metal salts of carboxylic acids such as caproic acid, capric acid, valeric acid, isovaleric acid, octylic acid, myristic acid and naphthenic acid. These can be used alone or in admixture of two or more.
Some of these isocyanurate-forming catalysts are used by being dissolved or dispersed in an active hydrogen compound such as a polyol, and the polyol reacts with an alicyclic isocyanate to form an allophanate group. Therefore, it is necessary for (B) modified alicyclic polyisocyanate to suppress the content of the active hydrogen compound in a range where allophanate group / isocyanurate group (molar ratio) = 0/100 to 5/95.
Of these, alkali metal salts of carboxylic acids are preferred.
The isocyanurate-forming catalyst is preferably used in an amount of 0.0001 to 1.0 mass%, particularly 0.001 to 0.1 mass%, based on the alicyclic isocyanate.
The isocyanuration reaction is preferably carried out in the range of 40 to 90 ° C. If the reaction temperature is less than 40 ° C, the reaction proceeds very slowly, and if it exceeds 90 ° C, it tends to be colored.

  After reaching the desired isocyanurate conversion rate, a stop agent such as acidic phosphoric acid ester, phosphoric acid or methyl paratoluenesulfonate is added to stop the isocyanurate reaction.

  In the modified polyisocyanate composition of the present invention, the viscosity needs to be 2000 mPa · s (25 ° C.) or less, and the NCO content is preferably 10 to 20% by mass. The blending ratio (mass ratio) of the aliphatic polyisocyanate and the (B) modified alicyclic polyisocyanate is preferably (A) / (B) = 90/10 to 70/30.

The modified polyisocyanate composition of the present invention can be diluted with a low-polar solvent and suitably used as a curing agent for a two-component polyurethane coating composition.
Specific examples of such low polarity solvents include methylcyclohexane (aniline point: 40 ° C.), ethylcyclohexane (aniline point: 44 ° C.), mineral spirit (aniline point: 56 ° C.), and turpentine oil (aniline point: 44 ° C.). In addition, it is a trade name marketed as a petroleum-based hydrocarbon, High Aromatic White Spirit (hereinafter referred to as “HAWS”) (manufactured by Shell Chemicals Japan, aniline point: 17 ° C.), Low Aromatic White Spirit (hereinafter “LAWS”)
(Shell Chemicals Japan Co., Ltd., aniline point: 44 ° C.), Essonaphtha No. 6 (ExxonMobil, aniline point: 43 ° C), Pegazole 3040 (ExxonMobil, aniline point: 55 ° C), A Solvent (manufactured by Nippon Oil Corporation, aniline point: 45 ° C), Clensol (Nippon Oil) Co., Ltd., aniline point: 64 ° C), mineral spirit A (manufactured by Nippon Oil Corporation, aniline point: 43 ° C), Hyalom 2S (manufactured by Nippon Oil Corporation, aniline point: 44 ° C), Solvesso 100 (ExxonMobil) Manufactured by Co., Ltd., mixed aniline point: 14 ° C.), Solvesso 150 (manufactured by ExxonMobil, mixed aniline point: 18.3 ° C.), Swazol 100 (manufactured by Maruzen Petrochemical Co., Ltd., mixed aniline point: 24.6 ° C.), swazol 200 (Maruzen Petrochemical Co., Ltd., mixed aniline point: 23.8 ° C.), Swazol 1000 (Maruzen Petrochemical Co., Ltd., mixed Aniline point: 12.7 ° C), Swazol 1500 (Maruzen Petrochemical Co., Ltd., mixed aniline point: 16.5 ° C), Swazol 1800 (Maruzen Petrochemical Co., Ltd., mixed aniline point: 15.7 ° C), Idemitsu Ipsol 100 (Idemitsu Kosan Co., Ltd., mixed aniline point: 13.5 ° C.), Idemitsu Ipsol 150 (Idemitsu Kosan Co., Ltd., mixed aniline point: 15.2 ° C.), Pegasol ARO-80 (Exxon Mobil Corp., mixed) Aniline point: 25 ° C.), Pegasol R-100 (manufactured by ExxonMobil Corporation, mixed aniline point: 14 ° C.), Akiraishi Toyo Hysol (manufactured by Shell Chemicals Japan Co., Ltd., mixed aniline point: 12.6 ° C.), Nisseki Hyzol (Manufactured by Nippon Oil Corporation, mixed aniline point: 17 ° C. or less).
These can be used alone or in admixture of two or more.
In addition, a polar organic solvent can also be mixed and used for these low polar organic solvents.
Here, the “aniline point” is a minimum temperature at which an equal volume of aniline and a sample (organic solvent) exist as a uniform mixed solution. The “mixed aniline point” is the lowest temperature at which 2 volumes of aniline, 1 volume of sample, and 1 volume of 1-heptane exist as a uniform mixed solution. The aniline point and mixed aniline point can be measured according to the aniline point and mixed aniline point test method described in JIS K 2256.
Since aniline has a freezing point of −6 ° C., the aniline point cannot be measured at temperatures below that. Therefore, a mixed aniline point is used in order to measure the solubility of the organic solvent over a wider area by mixing aniline with heptane.

The polyol used in the two-component polyurethane coating agent composition of the present invention has a hydroxyl value of 1 to 300 mgKOH / g, and is preferably dissolved or dispersed in a low polar organic solvent.
Specifically, saturated or unsaturated polyester polyol, polycaprolactone polyol, saturated or unsaturated oil-modified or fatty acid-modified alkyd polyol, amino alkyd polyol, polycarbonate polyol, acrylic polyol, polyether polyol, epoxy polyol, fluorine-containing polyol, Furthermore, saturated or unsaturated polyester resin, polycaprolactone resin, saturated or unsaturated oil-modified or fatty acid-modified alkyd resin, amino alkyd resin, polycarbonate resin, acrylic resin, polyether resin, epoxy resin, polyurethane resin, cellulose acetate butyrate Examples thereof include resins and fluorine-containing resins. Of these, acrylic polyols and acrylic resins are particularly preferred from the viewpoints of coating performance such as gloss, feeling of grip, hardness, flexibility and durability, workability such as drying and curing properties, and economic efficiency.

In the two-component polyurethane coating composition of the present invention, the molar ratio of the isocyanate group in the modified polyisocyanate composition to the hydroxyl group in the polyol having a hydroxyl value of 1 to 300 mgKOH / g is preferably 9: 1 to 1: 9. Is in the range of 6: 4 to 4: 6.
The two-component polyurethane coating agent composition of the present invention may contain various pigments and various additives commonly used in the lacquer industry in addition to the solvent.
Furthermore, the composition of the present invention can be applied by a conventional coating method conventionally used. For coating, an airless spray machine, an air spray machine, an electrostatic coating machine, dipping, a roll coater, a knife coater, a brush. Etc. can be used.

Hereinafter, the present invention will be described in more detail with reference to synthesis examples, examples and comparative examples.
Synthesis example 1
950 g of HDI (manufactured by Nippon Polyurethane Industry Co., Ltd .; NCO content = 49.9%) is added to a 1 liter four-necked flask equipped with a stirrer, a thermometer, a cooler, and a nitrogen gas inlet tube, and then iso-propanol Was heated to 85 ° C. while stirring and subjected to urethanization reaction for 3 hours. Then, 0.1 g of zirconium octylate as an allophanatization catalyst was charged into this reaction solution and reacted at 110 ° C. for 3 hours, and then an acidic phosphate ester JP-508 (made by Johoku Chemical Co., Ltd.) as a reaction terminator. ) And 0.1 g of the reaction was stopped at 50 ° C. for 1 hour. This reaction product was subjected to thin-film distillation at 130 ° C. and 0.04 kPa. The NCO content was 19.3%, the viscosity at 25 ° C. was 100 mPa · s, the free HDI content was 0.1%, Modified aliphatic polyisocyanate S-1 having a monoallophanate bond of 73% (GPC peak area)
Got. The molar ratio of the allophanate group and isocyanurate group of the modified aliphatic polyisocyanate S-1 was 98/2.

Example 1
90/10 (mass) of modified aliphatic polyisocyanate S-1 obtained in Synthesis Example 1 and VESTANAT T-1890 / 100 (IPDI-based isocyanurate-type modified polyisocyanate, manufactured by Tegusa Japan, NCO content = 17.2%) The modified polyisocyanate composition having an NCO content of 18.9% and a viscosity at 25 ° C. of 220 mPa · s was obtained. This modified polyisocyanate composition is designated as P-1.

Example 2
In the same manner as in Example 1, the modified aliphatic polyisocyanate S-1 obtained in Synthesis Example 1 and VESTANAT T-1890 / 100 were mixed at 85/15 (mass ratio), and the NCO content was 18.8%, 25 A modified polyisocyanate composition having a viscosity of 340 mPa · s at 0 ° C. was obtained. This modified polyisocyanate composition is designated as P-2.

Example 3
In the same manner as in Example 1, the modified aliphatic polyisocyanate S-1 obtained in Synthesis Example 1 and VESTANAT T-1890 / 100 were mixed at 75/25 (mass ratio), and the NCO content was 18.6%, 25 A modified polyisocyanate composition having a viscosity at 1000 ° C. of 1000 mPa · s was obtained. This modified polyisocyanate composition is designated as P-3.

Example 4
In the same manner as in Example 1, the modified aliphatic polyisocyanate S-1 obtained in Synthesis Example 1 and VESTANAT T-1890 / 100 were mixed at 70/30 (mass ratio), and the NCO content was 18.4%, 25 A modified polyisocyanate composition having a viscosity of 1760 mPa · s at 1 ° C. was obtained. This modified polyisocyanate composition is designated as P-4.

Comparative Example 1
In a 1-liter four-necked flask equipped with a stirrer, thermometer, cooler, and nitrogen gas inlet tube, 940.5 g of HDI, and then 59 of Sobamol 912 (12-hydroxystearyl alcohol; manufactured by Cognis Japan Co., Ltd.) .5 g was charged, and this was stirred and heated to 85 ° C. to carry out a urethanization reaction for 3 hours. And then, 0.1 g of zirconium octylate as an allophanatization catalyst was charged into this reaction solution, and after reacting at 110 ° C. for 3 hours, 0.1 g of acidic phosphate ester JP-508 as a reaction terminator was charged, Stop reaction was performed at 50 ° C. for 1 hour. This reaction product is subjected to thin film distillation at 130 ° C. and 0.04 kPa,
A modified aliphatic polyisocyanate having an NCO content of 16.7% and a viscosity at 25 ° C. of 780 mPa · s was obtained.
The resulting modified aliphatic polyisocyanate and VESTANAT T-1890 / 100 were mixed at 70/30 (mass ratio) to obtain a modified polyisocyanate composition. This modified polyisocyanate composition is designated as H-1. About H-1, although the tolerance test was done, since the viscosity was too high, the other performance test was not done.

Comparative Example 2
90/10 (mass ratio) of modified aliphatic polyisocyanate S-1 obtained in Synthesis Example 1 and coronate HXLV (HDI isocyanurate type modified polyisocyanate, manufactured by Nippon Polyurethane Industry Co., Ltd., NCO content = 23.1%) The modified polyisocyanate composition having an NCO content of 19.5% and a viscosity at 25 ° C. of 130 mPa · s was obtained. This modified polyisocyanate composition is designated as H-2.

Comparative Example 3
The modified aliphatic polyisocyanate S-1 obtained in Synthesis Example 1 and coronate HXLV are mixed at 85/15 (mass ratio), and the NCO content is 19.7% and the viscosity at 25 ° C. is 340 mPa · s. A composition was obtained. This modified polyisocyanate composition is designated as H-3.

〔tolerance〕
1 g of each of the modified polyisocyanate compositions obtained in Examples 1 to 4 and Comparative Examples 1 to 3, and various solvents listed in Table 1 and Table 2 were added little by little with a burette, and well-mixed and turbid. The end point was determined and the required number of grams of solvent at that time was determined. And the tolerance (solvent dilution property) corresponding to various solvents was calculated | required with the following formula.
Tolerance = required g of solvent / sample amount (1 g)
* The higher this value, the better the solvent dilution.
These results are shown in Tables 1 and 2.

〔performance test〕
Each of the modified polyisocyanate compositions obtained in Examples 1 to 4 and Comparative Examples 1 to 3 was mixed with solvent HAWS (High
A composition composed of each solution dissolved in Aromatic White Spirit) and acrylic polyol (Acridic HU-596, manufactured by Dainippon Ink & Chemicals, Inc., hydroxyl value 30 mg KOH / g, solid content = 50%) is degreased with methyl ethyl ketone. Steel plate (JIS
G3141 SPCC-SB, PF-1077 treatment (manufactured by Nippon Test Panel Industry Co., Ltd.) using an applicator with a wet thickness of 100 μm, curing for one week in an environment of 20 ° C. and 65% RH, and a dry film thickness of 30-40 μm The coating film was formed.
These coating films were evaluated using the following method. In order to evaluate the drying property of the coating film, it was performed using a drying recorder (RIKEN OPTICAL: present-day Ricoh Co., Ltd.). In addition, bending resistance test (cylindrical mandrel method) to evaluate resistance to cracks, cracks, and peeling from the metal substrate when bent by a cylindrical mandrel (conforms to JIS K5600-5-1) ), A cupping resistance test (in accordance with JIS K5600-5-2) for evaluating the resistance to cracking, cracking, and peeling from the metal substrate when the coating film is partially deformed by indentation, weight Weight drop resistance test (DuPont method) (based on JIS K5600-5-3) for evaluating the resistance to cracks, cracks, and peeling from the metal substrate, and the hardness of the coating surface is evaluated. Scratch hardness test (pencil method) (based on JIS K5600-5-4), cross-cut tape test (JIS)
According to K5600-8-5-2).
A weather resistance test (according to JIS K5600-7-8) after 1056 hours of irradiation with QUV was performed. The weather resistance test equipment is manufactured by Q-Panel, and the cycle condition is 1 cycle UV.
Irradiation is 8 hours at 70 ° C., and condensation (dark) is 4 hours at 50 ° C.
Contamination resistance test conforms to antifouling materials and performance evaluation test method (1 type of antifouling materials for civil engineering) in the application technical guidelines for civil engineering structures prepared by the National Institute of Civil Engineering And carried out.
These results are shown in Tables 3 and 4.

Claims (6)

A modified polyisocyanate composition having a viscosity of 2000 mPa · s (25 ° C.) or less, comprising the following (A) and (B):
(A) A modified aliphatic polyisocyanate having an allophanate group / isocyanurate group (molar ratio) of 100/0 to 90/10, obtained from an aliphatic diisocyanate and a monool having 3 to 20 carbon atoms.
(B) Modified alicyclic polyisocyanate having an allophanate group / isocyanurate group (molar ratio) of 0/100 to 5/95. A modified polyisocyanate composition having a viscosity of 2000 mPa · s (25 ° C.) or less and an isocyanate content of 10 to 20% by mass, comprising the following (A) and (B):
(A) A modified aliphatic polyisocyanate having an allophanate group / isocyanurate group (molar ratio) of 100/0 to 90/10, obtained from an aliphatic diisocyanate and a monool having 3 to 20 carbon atoms.
(B) Modified alicyclic polyisocyanate having an allophanate group / isocyanurate group (molar ratio) of 0/100 to 5/95.   The modified polyisocyanate composition according to claim 1 or 2, wherein the (A) / (B) (mass ratio) is 90/10 to 70/30.   The modified polyisocyanate composition according to any one of claims 1 to 3, further comprising a low-polar organic solvent.   A two-component polyurethane coating composition comprising a polyol having a hydroxyl value of 1 to 300 mgKOH / g and the modified polyisocyanate composition according to any one of claims 1 to 4.   A two-component type comprising a polyol having a hydroxyl value of 1 to 300 mgKOH / g dissolved or dispersed in a low polarity organic solvent and the modified polyisocyanate composition according to any one of claims 1 to 4. Polyurethane coating agent composition.