CN111621000B - Polyisocyanate composition, coating composition and coating film - Google Patents

Abstract

Provided are polyisocyanate compositions, coating compositions and coating films. Provided are a polyisocyanate composition and a coating film using the same, wherein the polyisocyanate composition contains a polyisocyanate, contains allophanate groups, isocyanurate groups and urethane groups, and when the mole number of the allophanate groups is A, the mole number of the isocyanurate groups is B, and the mole number of the urethane groups is C, the ratio of C/B is 0.06-5.50, the polyisocyanate is obtained from (A) at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates and at least one polyol selected from the group consisting of (B1) polyether polyols having oxypropylene groups with a number average molecular weight of 400 to 10000 and (B2) polyester polyols having a number average molecular weight of 250 to 4000 derived from 2-to 3-membered alcohols and epsilon-caprolactone.

Description

Polyisocyanate composition, coating composition and coating film

Technical Field

The present invention relates to a polyisocyanate composition, a coating composition and a coating film.

Background

Coating compositions using polyisocyanate compositions are excellent in appearance, weather resistance and durability, and therefore are widely used as coatings for buildings, automobiles, plastics, information appliances and the like. Among these, in applications requiring high-quality appearance and excellent weather resistance and durability, such as applications for coating the surface of automobiles and buildings, a two-component type polyurethane coating which can form a dense crosslinked coating film and has good finished appearance is highly evaluated.

In the field of automobile use, building use, and the like, a coating composition having the above-described properties and also having good water resistance, stretchability, bendability, and adhesion to a substrate is desired. Conventionally, in the production of such a coating composition, a method has been employed in which a coating film is made to have high hardness by using a composition obtained by isocyanurating a raw material containing a polyol such as an acrylic polyol or a polyester polyol as a main component, a diisocyanate such as hexamethylene diisocyanate (hereinafter, may be abbreviated as "HDI") as a curing component, and a polyol. However, the isocyanurated composition may cause a coating film to be hard, and therefore, the flexibility may be lowered, and the coating film may not be able to follow expansion and contraction of the coating film due to a change in temperature, or the coating film may be broken. In order to solve this problem, methods for imparting stretchability to a coating film are disclosed in, for example, patent documents 1 and 3. Patent document 1 discloses a reaction product of an aliphatic diisocyanate or an alicyclic diisocyanate and a polyether polyol having an oxypropylene group. Patent document 3 discloses a reaction product of an aliphatic diisocyanate or an alicyclic diisocyanate and a polycaprolactone polyol.

Examples of other methods for producing a high-functional polyisocyanate composition other than the isocyanurated composition include a method in which a diisocyanate such as HDI and an alcohol are used as raw materials and allophanatized. The allophanatization reaction is a method in which an isocyanate group and a urethane group are subjected to an addition reaction, and the urethane gene reaction, which is a raw material of the allophanatization reaction, is gradually reduced. Therefore, the reaction is naturally reduced, and the increase in molecular weight such as the isocyanurate reaction is less likely to occur, and therefore, a polyisocyanate composition having a low viscosity can be obtained. For example, patent document 2 discloses a method for producing an allophanate group-containing polyisocyanate composition using a polyester polyol derived from epsilon-caprolactone. Patent document 2 discloses a polyisocyanate composition having an allophanate group, which uses a diisocyanate such as HDI and a polyester polyol having a number average molecular weight of 250 to 2000 derived from an alcohol and epsilon-caprolactone as raw materials. By using a curing agent containing the polyisocyanate composition and a polyol-containing main agent, weather resistance, durability, scratch resistance and drying property can be imparted.

Documents of the prior art

Patent document

Patent document 1: japanese patent No. 5388405

Patent document 2: japanese patent laid-open publication No. 2011- & gt105886

Patent document 3: japanese laid-open patent publication No. 61-028518

Disclosure of Invention

Problems to be solved by the invention

In the methods disclosed in patent documents 1 and 3, the resulting coating film may have insufficient water resistance and weather resistance.

In addition, in the composition disclosed in patent document 2, the influence on the water resistance and adhesion of the obtained coating film has not been studied.

The present invention has been made in view of the above circumstances, and provides a polyisocyanate composition excellent in water resistance, weather resistance, bendability and adhesion when formed into a coating film, and a coating composition and a coating film using the polyisocyanate composition.

The present invention also provides a polyisocyanate composition which is excellent in water resistance, weather resistance and stretchability when formed into a coating film, and a coating composition and a coating film using the polyisocyanate composition.

Means for solving the problems

That is, the present invention includes the following aspects.

[1] A polyisocyanate composition comprising a polyisocyanate and containing allophanate groups, isocyanurate groups and urethane groups,

when the number of moles of the allophanate groups is represented by A, the number of moles of the isocyanurate groups is represented by B and the number of moles of the urethane groups is represented by C, C/B is 0.06 to 5.50,

the polyisocyanate is obtained from (A) at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates and at least one polyol selected from the group consisting of (B1) polyether polyols having oxypropylene groups with a number average molecular weight of 400 to 10000 and (B2) polyester polyols having a number average molecular weight of 250 to 4000 derived from 2-to 3-membered alcohols and epsilon-caprolactone.

[2] The polyisocyanate composition according to [1], wherein the polyisocyanate is a polyisocyanate obtained from (A) at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates and (B1) a polyether polyol having oxypropylene groups and a number average molecular weight of 400 to 10000, A/B is 0.10 to 2.50,

the average number of isocyanate functional groups is 2.6 or more and 10.0 or less.

[3] The polyisocyanate composition according to [1], wherein the polyisocyanate is a polyisocyanate obtained from (A) at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates and (B2) a polyester polyol having a number average molecular weight of 250 or more and 4000 or less and derived from 2-or more and 3-or less-membered alcohol and epsilon-caprolactone,

C/(A + C) is 0.45-0.99, and B/(A + B + C) is 0.40-0.90.

[4] A coating composition comprising:

a polyol having a hydroxyl value of 5mgKOH/g or more and 200mgKOH/g or less; and

[1] the polyisocyanate composition according to any one of [1] to [3 ].

[5] The coating composition according to [4], which is used for coating of metal or plastic.

[6] The coating composition according to [4] or [5], which is used as a top clear coating for building structures, automobile bodies, automobile metal parts, automobile plastic parts, metal parts for information home appliances, or plastic parts for information home appliances.

[7] A coating film obtained by curing the coating composition according to any one of [4] to [6 ].

ADVANTAGEOUS EFFECTS OF INVENTION

According to the polyisocyanate composition of the above aspect, a polyisocyanate composition excellent in water resistance, weather resistance, bendability and adhesion when formed into a coating film can be provided. The coating composition of the above embodiment contains the polyisocyanate composition, and can provide a coating film excellent in water resistance, weather resistance, bendability, and adhesion. The coating film of the above embodiment is obtained by curing the above coating composition, and is excellent in water resistance, weather resistance, bendability and adhesion.

Further, according to the polyisocyanate composition of the above aspect, a polyisocyanate composition excellent in water resistance, weather resistance and stretchability when formed into a coating film can be provided. The coating composition of the above embodiment contains the polyisocyanate composition, and can give a coating film excellent in water resistance, weather resistance and stretchability. The coating film of the above embodiment is obtained by curing the above coating composition, and is excellent in water resistance, weather resistance and stretchability.

Detailed Description

The present embodiment (hereinafter referred to as "the present embodiment") will be described in detail below. The following embodiments are illustrative of the present invention, and the present invention is not limited to the following. The present invention can be variously modified within a range not departing from the gist thereof.

In the present specification, the term "polyol" refers to a compound having 2 or more hydroxyl groups (-OH) in one molecule.

In the present specification, the term "polyisocyanate" refers to a reaction product in which a plurality of monomer compounds having 2 or more isocyanate groups (-NCO) are bonded.

In the present specification, "(meth) acrylic" includes methacrylic and acrylic and "(meth) acrylate" includes methacrylate and acrylate unless otherwise specified.

Polyisocyanate composition

The polyisocyanate composition of the present embodiment contains a polyisocyanate obtained from (a) a diisocyanate and (B1) a polyether polyol and/or a polyester polyol. That is, the polyisocyanate is a reaction product of (A) diisocyanate and (B1) polyether polyol and/or polyester polyol. The diisocyanate (a) is at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates. The polyether polyol (B1) is a polyether polyol having oxypropylene groups and has a number average molecular weight of 400 to 10000, and the polyester polyol (B2) is derived from a 2-to 3-membered alcohol and epsilon-caprolactone, that is, a reaction product of a 2-to 3-membered alcohol and epsilon-caprolactone and has a number average molecular weight of 250 to 4000.

Further, the polyisocyanate composition of the present embodiment contains allophanate groups, isocyanurate groups and urethane groups. In the polyisocyanate composition of the present embodiment, these functional groups may be all contained in 1 polyisocyanate, or the polyisocyanate composition of the present embodiment may be a mixture of polyisocyanates containing at least 1 functional group among these functional groups.

In the polyisocyanate composition of the present embodiment, when the number of moles of allophanate groups is denoted by a, the number of moles of isocyanurate groups is denoted by B, and the number of moles of urethane groups is denoted by C, C/B is 0.06 or more and 5.50 or less, preferably 0.08 or more and 4.50 or less, more preferably 0.09 or more and 2.00 or less, and still more preferably 0.10 or more and 1.50 or less.

When C/B is not less than the lower limit, the flexibility of the coating film can be further improved.

The molar ratios of the allophanate groups, isocyanurate groups and urethane groups can be determined by the following examples¹³Determined by C-NMR measurement.

In the polyisocyanate composition of the present embodiment, when the polyisocyanate is a polyisocyanate obtained from the diisocyanate (a) and the polyether polyol (B1), the average isocyanate functional group number is preferably 2.6 or more and 10.0 or less, more preferably 2.7 or more and 9.0 or less, further preferably 2.8 or more and 8.5 or less, and particularly preferably 2.9 or more and 8.0 or less in a state where the polyisocyanate composition is not diluted with a solvent such as n-butyl acetate.

When the average isocyanate functional group number is not less than the lower limit, the water resistance of the coating film can be further improved. On the other hand, an excessive increase in viscosity can be more effectively suppressed by being equal to or less than the upper limit value.

The average number of isocyanate functional groups (hereinafter, sometimes referred to as "average isocyanate (NCO) number" or "number average functional group number (fn)") can be calculated by using the following formula as described in the examples described below. In the formula, "NCO%" represents the content of isocyanate group, and "Mn" represents the number average molecular weight.

Average isocyanate (NCO) number ═ Mn × NCO% × (0.01)/42

In the polyisocyanate composition of the present embodiment, when the polyisocyanate is a polyisocyanate obtained from the diisocyanate (a) and the polyether polyol (B1), a/B is preferably 0.10 or more and 2.50 or less, more preferably 0.20 or more and 2.35 or less, still more preferably 0.30 or more and 2.00 or less, and particularly preferably 0.35 or more and 1.90 or less.

When the a/B is not less than the lower limit, the adhesion when forming a coating film can be further improved, and when the a/B is not more than the upper limit, the weather resistance when forming a coating film can be further improved.

By providing the polyisocyanate composition of the present embodiment with the above-described configuration, a coating film obtained therefrom is excellent in water resistance, weather resistance, bendability, and adhesion.

In the polyisocyanate composition of the present embodiment, when the polyisocyanate is a polyisocyanate obtained from the diisocyanate (a) and the polyester polyol (B1), C/(a + C) is preferably 0.45 or more and 0.99 or less, more preferably 0.50 or more and 0.98 or less, further preferably 0.57 or more and 0.97 or less, further preferably 0.70 or more and 0.97 or less, and particularly preferably 0.80 or more and 0.96 or less. When C/(a + C) is not less than the lower limit, the water resistance and stretchability of the coating film can be further improved.

B/(a + B + C) is preferably 0.40 or more and 0.90 or less, more preferably 0.40 or more and 0.85 or less, further preferably 0.50 or more and 0.85 or less, further preferably 0.60 or more and 0.85 or less, and particularly preferably 0.72 or more and 0.85 or less. When B/(a + B + C) is equal to or higher than the lower limit, the weather resistance and water resistance can be further improved, while when B/(a + B + C) is equal to or lower than the upper limit, the stretchability of the coating film can be further improved.

By providing the polyisocyanate composition of the present embodiment with the above-described configuration, a coating film obtained therefrom is excellent in water resistance, weather resistance and stretchability.

Next, each constituent component of the polyisocyanate composition of the present embodiment will be described in detail below.

< diisocyanate (A) >

(A) The diisocyanate is at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates.

The aliphatic diisocyanate refers to a compound having a saturated aliphatic group in the molecule. On the other hand, the alicyclic diisocyanate refers to a compound having a cyclic aliphatic group in the molecule. When an aliphatic diisocyanate is used, the resulting polyisocyanate composition becomes low in viscosity, and therefore, it is preferable.

Examples of the aliphatic diisocyanate include 1, 4-diisocyanatobutane, 1, 5-diisocyanatopentane, 1, 6-diisocyanatohexane (HDI), 1, 6-diisocyanato-2, 2, 4-trimethylhexane, and methyl 2, 6-diisocyanatohexanoate (lysine diisocyanate).

Examples of the alicyclic diisocyanate include 5-isocyanato-1-isocyanatomethyl-1, 3, 3-trimethylcyclohexane (isophorone diisocyanate; hereinafter sometimes abbreviated as "IPDI"), 1, 3-bis (isocyanatomethyl) cyclohexane (hydrogenated xylylene diisocyanate), bis (4-isocyanatocyclohexyl) methane (hydrogenated diphenylmethane diisocyanate), 1, 4-diisocyanatocyclohexane and the like.

These diisocyanates may be used alone in 1 kind, or in combination in 2 or more kinds.

Among them, as the diisocyanate (a), HDI, IPDI, hydrogenated xylylene diisocyanate, or hydrogenated diphenylmethane diisocyanate is preferable from the viewpoint of easy industrial availability. In addition, HDI is particularly preferable because it is extremely excellent in weather resistance and flexibility of the coating film.

Hereinafter, the aliphatic diisocyanate and the alicyclic diisocyanate may be collectively referred to as a diisocyanate.

< polyether polyol (B1) >

(B1) The polyether polyol is a polyether polyol having a number average molecular weight of 400 to 10000 and an oxypropylene group. The polyether polyol having oxypropylene groups mentioned herein means a polyether polyol having oxypropylene groups in the molecular chain. In this case, the oxyalkylene repeating unit may contain other oxyalkylene groups, specifically, an oxyethylene group, an oxytetramethylene group, an oxycyclohexyl group, an oxystyrene group, or the like.

The content of the oxypropylene group having a side chain is preferably 60 mol% or more, more preferably 70 mol% or more, and still more preferably 80 mol% or more, based on the total molar amount of the oxyalkylene repeating units.

(B1) The upper limit of the number average molecular weight of the polyether polyol is 10000, preferably 7000, more preferably 5000, and still more preferably 3500. On the other hand, the lower limit of the number average molecular weight is 400, preferably 450, more preferably 500.

That is, the number average molecular weight of the (B1) polyether polyol is 400 or more and 10000 or less, preferably 450 or more and 7000 or less, more preferably 500 or more and 5000 or less, and further preferably 500 or more and 3500 or less.

When the number average molecular weight of the polyether polyol (B1) is in the above range, the flexibility of the resulting coating film is more sufficient, and the curability of the coating film is also more sufficient.

The number average molecular weight of the polyether polyol can be obtained by measurement using gel permeation chromatography (hereinafter, sometimes abbreviated as "GPC").

Specific examples of the polyether polyol (B1) include polypropylene glycol or polyglycerol, Pluronic-type polypropylene glycol or polyglycerol obtained by addition polymerization of ethylene oxide to the terminals of polypropylene glycol, polyoxypropylene-polyoxyethylene copolymer glycol or triol, polyoxypropylene-polyoxyethylene block polymer glycol or triol, polytetramethylene glycol or triol, polyoxypropylene-polyoxybutylene copolymer glycol or triol, polyoxypropylene-polyoxybutylene block polymer glycol or triol, and polyoxycyclohexane glycol. Among them, the polyether polyol (B1) is preferably polypropylene glycol or polyglycerol, or polypropylene glycol or polyglycerol of the Pluronic type obtained by addition polymerization of ethylene oxide to the terminal of polypropylene glycol, from the viewpoint of excellent solubility in a low-polarity organic solvent. Among these, as the polyether polyol (B1), polypropylene glycol or polyglycerol of the so-called Pluronic type obtained by addition polymerization of ethylene oxide to the terminal of polypropylene glycol is more preferable in terms of excellent reactivity.

These (B1) polyether polyols may be used alone in 1 kind, or may be used in combination in 2 or more kinds.

Examples of commercially available products of the polyether polyol (B1) include EXCENOL 840 (trade name, product of AGC, polyglycerol, number average molecular weight 6500), EXCENOL 510 (trade name, product of AGC, polypropylene glycol, number average molecular weight 4000), EXCENOL 230 (trade name, product of AGC, polyglycerol, number average molecular weight 3000), EXCENOL 2020 (trade name, product of AGC, polypropylene glycol, number average molecular weight 2000), EXCENOL 1030 (trade name, product of AGC, polyglycerol, number average molecular weight 1000), EXCENOL 1020 (trade name, product of AGC, product of polypropylene glycol, number average molecular weight 1000), PREMINOL 7012 (trade name, product of AGC, polyglycerol, number average molecular weight 10000), PTG1000SN (trade name, product of Fugu chemical, polytetramethylene glycol, number average molecular weight 1000), and the like.

Examples of the method for producing the polyether polyol (B1) include the following methods: a method for producing a polyol, a polyhydric phenol, a polyamine, an alkanolamine, etc. singly or in combination with a catalyst by adding propylene oxide (and optionally other alkylene oxides themselves or in combination) thereto; a method for producing a polyol by dehydration condensation, and the like.

The polyol may be a diol or a triol. Examples of the dihydric alcohol include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, neopentyl glycol, 1, 4-butanediol, 1, 6-hexanediol, and bisphenol a. Examples of the trihydric alcohol include glycerin and trimethylolpropane. Examples of the polyamine include diamines such as ethylenediamine.

Examples of the catalyst include hydroxides of lithium, sodium, potassium, and the like; strong basic catalysts such as alkoxides and alkylamines; a metalloporphyrin; a complex metal cyano compound complex; a complex of a metal and a chelating agent coordinated with three or more teeth; and complex metal complexes such as zinc hexacyanocobaltate complexes.

Examples of the other alkylene Oxide include butylene Oxide, cyclohexene Oxide, ethylene Oxide, Styrene Oxide (Styrene Oxide), and the like.

< polyester polyol (B2) >

(B2) The polyester polyol is derived from 2-to 3-membered alcohol and epsilon-caprolactone, that is, a reaction product of 2-to 3-membered alcohol and epsilon-caprolactone. Epsilon-caprolactone is 1 of cyclic ester and lactone, and has chemical formula (CH)₂)₅CO₂A seven-membered ring compound is shown. Polycaprolactone as a polyester polymer is obtained by ring-opening polymerization of epsilon-caprolactone.

Examples of the alcohol having 2 or more and 3 or less atoms include 1, 2-propanediol, 1, 3-butanediol, neopentyl glycol, hydroxypivalate of neopentyl glycol, 2-methyl-1, 3-propanediol, 2,3, 5-trimethylpentanediol, ethylene glycol, diethylene glycol, 1, 3-propanediol, 1, 4-butanediol, 1, 5-pentanediol, 1, 6-hexanediol, trimethylolpropane, glycerol, 1, 7-trimethylolheptane, 1,2, 7-trimethylolheptane and the like. These 2-to 3-membered alcohols may be used alone in 1 kind or in combination of 2 or more kinds.

(B2) The upper limit of the number average molecular weight of the polyester polyol is 4000, preferably 3000, and more preferably 2500. On the other hand, the lower limit of the number average molecular weight of the (B2) polyester polyol is 250.

That is, the number average molecular weight of the (B2) polyester polyol is 250 to 4000, preferably 250 to 3000, and more preferably 250 to 2500.

When the number average molecular weight of the polyester polyol (B2) is in the above range, the stretchability when forming a coating film becomes more sufficient, and an excessive increase in the viscosity of the obtained coating liquid can be more effectively suppressed.

The number average molecular weight of the polyester polyol can be obtained by gel permeation chromatography (hereinafter, sometimes abbreviated as "GPC") measurement.

(B2) The polyester polyol may be used alone in 1 kind, or may be used in combination in 2 or more kinds.

< method for producing polyisocyanate composition >

In the production of the polyisocyanate composition of the present embodiment, at least HDI is preferably used as a raw material.

The polyisocyanate composition of the present embodiment can be obtained by: for example, the isocyanuric reaction, the allophanation reaction and the urethanation reaction are performed separately in this order or simultaneously, these reactions are performed in the presence of an excess amount of diisocyanate monomer and polyether-based polyol or polyester-based polyol, and after the reaction is completed, unreacted diisocyanate monomer is removed. Further, a polyisocyanate composition can be obtained by mixing the products obtained by carrying out the above-mentioned 3 reactions, respectively.

In the method for producing the polyisocyanate composition of the present embodiment, an alcohol such as an alkyl monohydric alcohol or an alkyl glycol may be used in combination as a side material. When an alcohol is used, it is preferable to use a polyisocyanate composition of the present embodiment in which A/B, C/B, C/(A + C) and B/(A + B + C) fall within the above-mentioned ranges, as described above.

Alternatively, the polyisocyanate composition of the present embodiment can be obtained by: for example, the polyisocyanate is produced by subjecting a diisocyanate to an isocyanuric reaction and an allophanatization reaction, and then subjecting the resultant reaction product to a urethanization reaction with a polyether polyol or a polyester polyol. In this case, the molar ratio of the isocyanate group in the reaction product to the hydroxyl group of the polyester polyol is preferably 2/1 or more and 40/1 or less, more preferably 3/1 or more and 30/1 or less, and further preferably 4/1 or more and 20/1 or less.

Next, the respective reactions of the isocyanuric reaction, the allophanation reaction and the urethanization reaction will be described in detail below.

[ Isocyanuration reaction ]

When deriving an isocyanurate group-containing polyisocyanate from a diisocyanate monomer, an isocyanuric acid esterification catalyst is generally used.

As the isocyanuric acid esterification reaction catalyst, a catalyst having basicity is preferable. Examples of the catalyst for the isocyanuric acid esterification reaction include the following catalysts 1) to 7). 1) A hydroxide or weak organic acid salt of tetraalkylammonium; 2) hydroxides or weak organic acid salts of hydroxyalkylammonium; 3) metal salts of alkyl carboxylic acids; 4) metal alkoxides such as sodium and potassium; 5) a compound containing an aminosilyl group such as hexamethyldisilazane; 6) mannich bases; 7) tertiary amines are used in combination with epoxy compounds.

Examples of the tetraalkylammonium include tetramethylammonium and tetraethylammonium.

Examples of the weak organic acid include acetic acid and capric acid.

Examples of the hydroxyalkylammonium include trimethylhydroxypropylammonium, trimethylhydroxyethylammonium, triethylhydroxypropylammonium, and triethylhydroxyethylammonium.

Examples of the alkyl carboxylic acid include acetic acid, caproic acid, caprylic acid, and myristic acid.

Examples of the metal constituting the metal salt include tin, zinc, lead, sodium, and potassium.

Among them, the isocyanuric acid esterification catalyst is preferably an organic weak acid salt of 1), 2), 3), 4), or 5) described above, more preferably 1), from the viewpoint of catalytic efficiency.

The amount of the isocyanuric acid esterification catalyst added is preferably 10ppm to 1000ppm, more preferably 10ppm to 500ppm, and still more preferably 10ppm to 100ppm, based on the mass of the diisocyanate to be charged.

The lower limit of the isocyanuric acid esterification reaction temperature is preferably 50 ℃, more preferably 54 ℃, still more preferably 57 ℃, and particularly preferably 60 ℃. On the other hand, the upper limit of the isocyanuric acid esterification reaction temperature is preferably 120 ℃, more preferably 100 ℃, still more preferably 90 ℃, and particularly preferably 80 ℃.

That is, the isocyanuric acid esterification reaction temperature is preferably 50 ℃ or more and 120 ℃ or less, more preferably 54 ℃ or more and 100 ℃ or less, still more preferably 57 ℃ or more and 90 ℃ or less, and particularly preferably 60 ℃ or more and 80 ℃ or less.

When the isocyanuric acid esterification reaction temperature is not higher than the upper limit, changes in characteristics such as coloring can be more effectively prevented.

[ allophanatization reaction ]

Polyisocyanates containing allophanate groups can be obtained by adding an alcohol to a diisocyanate and using an allophanatization catalyst. The alcohol used may contain ether groups, ester groups, carbonyl groups in the molecule, and is preferably a monohydric alcohol containing a saturated hydrocarbon group and a hydroxyl group, and more preferably a monohydric alcohol having a branched chain. Examples of such monohydric alcohols include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutanol, 1-pentanol, 2-pentanol, isopentanol, 1-hexanol, 2-hexanol, 1-heptanol, 1-octanol, 2-ethyl-1-hexanol, 3, 5-trimethyl-1-hexanol, tridecanol, pentadecanol, palmitic alcohol, stearyl alcohol, cyclopentanol, cyclohexanol, methylcyclohexanol, and trimethylcyclohexanol. Among these, as the monohydric alcohol, isobutanol, 1-butanol, isoamyl alcohol, 1-hexanol, 1-heptanol, 1-octanol, 2-ethyl-1-hexanol, tridecyl alcohol, pentadecyl alcohol, palmityl alcohol, stearyl alcohol, or 1,3, 5-trimethylcyclohexanol is preferable because it is particularly excellent in solubility in a low-polarity organic solvent. Further, from the viewpoint of lowering the viscosity, 1-propanol, isobutanol, 1-butanol, isoamyl alcohol, 1-pentanol, 2-pentanol, 1-hexanol, 2-hexanol, 1-heptanol, 1-octanol, 2-ethylhexanol or 3,3, 5-trimethyl-1-hexanol is preferable. Further, isobutanol, 2-hexanol, 2-octanol, 2-ethyl-1-hexanol, or 3,3, 5-trimethyl-1-hexanol is more preferable because it is very excellent in solubility in a low-polarity organic solvent.

The amount of the alcohol to be added is not limited to the following amount, but is preferably such an amount that the molar ratio of the isocyanate group of the diisocyanate to the hydroxyl group of the alcohol becomes 10/1 or more and 1000/1 or less, and more preferably 100/1 or more and 1000/1 or less. When the molar ratio of the isocyanate group of the diisocyanate to the hydroxyl group of the alcohol is not less than the lower limit, a more appropriate average number of isocyanate groups can be secured for the obtained polyisocyanate.

The allophanation reaction catalyst is not limited to the following catalysts, and examples thereof include alkylcarboxylates of tin, lead, zinc, bismuth, zirconium, Zirconyl (zirconium), and the like.

Examples of the tin alkylcarboxylate (organotin compound) include tin 2-ethylhexanoate and dibutyltin dilaurate.

Examples of the alkyl carboxylate of lead (organolead compound) include lead 2-ethylhexanoate and the like.

Examples of the zinc alkylcarboxylate (organozinc compound) include zinc 2-ethylhexanoate and the like.

Examples of the alkyl carboxylate of bismuth include bismuth 2-ethylhexanoate and the like.

Examples of the alkyl carboxylate of zirconium include zirconium 2-ethylhexanoate and the like.

Examples of the alkylcarboxylate of zirconia include zirconyl 2-ethylhexanoate and the like.

At the point of time when the desired yield is reached, a deactivator for the allophanatization catalyst such as phosphoric acid or methyl p-toluenesulfonate may be added to stop the allophanatization reaction.

The amount of the allophanatization reaction catalyst used is preferably 10ppm to 10000ppm, more preferably 10ppm to 1000ppm, and still more preferably 10ppm to 500ppm, in terms of a mass ratio, relative to the diisocyanate as a raw material.

The reaction temperature for allophanatization is preferably 60 ℃ to 160 ℃, more preferably 70 ℃ to 155 ℃, still more preferably 80 ℃ to 150 ℃, and particularly preferably 90 ℃ to 145 ℃.

When the allophanatization reaction temperature is not higher than the above upper limit, the resulting polyisocyanate can be more effectively prevented from changing in properties such as coloration.

The reaction time for allophanatization is preferably 0.2 hours or more and 8 hours or less, more preferably 0.4 hours or more and 6 hours or less, still more preferably 0.6 hours or more and 4 hours or less, particularly preferably 0.8 hours or more and 3 hours or less, and most preferably 1.0 hour or more and 2 hours or less.

When the reaction time for allophanatization is equal to or more than the lower limit value, a lower viscosity can be obtained, and when the reaction time is equal to or less than the upper limit value, coloring of the polyisocyanate itself can be further suppressed.

Further, the above-mentioned isocyanuric acid esterification reaction catalyst may be used as an allophanation reaction catalyst. When the allophanatization reaction is carried out using the above-mentioned isocyanurate-forming reaction catalyst, an isocyanurate group-containing polyisocyanate is also produced at the same time. Among them, from the viewpoint of economy and productivity improvement, it is preferable to use the above-mentioned isocyanurate-forming reaction catalyst as an allophanation reaction catalyst to carry out an allophanation reaction and an isocyanurate-forming reaction.

[ Carbamidation reaction ]

In the method for producing the polyisocyanate composition of the present embodiment, the urethanization reaction is preferably performed after the isocyanuric reaction and the allophanatization reaction, and specifically, it is preferable that the isocyanuric reaction and the allophanatization reaction are performed sequentially or simultaneously to obtain a polyisocyanate containing isocyanurate groups and allophanate groups, and then the obtained polyisocyanate is urethanized with the polyether polyol or the polyester polyol.

The lower limit of the temperature of the urethanization reaction is preferably 80 ℃ and more preferably 100 ℃. On the other hand, the upper limit of the reaction temperature is preferably 150 ℃ and more preferably 130 ℃.

That is, the temperature of the urethanization reaction is preferably 80 ℃ to 150 ℃, more preferably 100 ℃ to 130 ℃.

The polymerization reaction is stopped at the point when the polymerization reaction of the above-mentioned isocyanurated reaction, allophanated reaction and urethanized reaction reaches a desired degree of polymerization. The termination of the polymerization reaction is not limited to the following method, and can be achieved by, for example, adding an acidic compound to the reaction solution to neutralize the polymerization catalyst, or by inerting the reaction solution by thermal decomposition, chemical decomposition, or the like. Examples of the acidic compound include phosphoric acid, acid phosphate, sulfuric acid, hydrochloric acid, and sulfonic acid compounds. After the reaction was stopped, filtration was performed if necessary.

The reaction liquid immediately after the reaction is stopped usually contains unreacted diisocyanate monomer, and therefore, it is preferable to remove it by a thin film evaporator, extraction, or the like. By performing such post-treatment, the concentration of the diisocyanate monomer contained in the polyisocyanate composition is preferably controlled to 1% by mass or less.

For example, in the case where the diisocyanate monomer is HDI, the diisocyanate monomer concentration can be measured by the method described in the examples below.

< physical Properties of polyisocyanate composition >

[ viscosity ]

The viscosity at 25 ℃ when a polyisocyanate composition containing a polyisocyanate obtained from the diisocyanate (a) and the polyether polyol (B1) is diluted with butyl acetate and the solid content is adjusted to 75 mass% is not particularly limited, but is preferably 100mPa · s or more and 5000mPa · s or less, more preferably 120mPa · s or more and 4500mPa · s or less, and still more preferably 130mPa · s or more and 4000mPa · s or less, from the viewpoints of the amount of organic solvent and the number of functional groups. If the viscosity is not lower than the lower limit, the number of functional groups can be increased more sufficiently, while if it is not higher than the upper limit, the amount of the organic solvent can be further reduced.

The viscosity at 25 ℃ when a polyisocyanate composition containing a polyisocyanate obtained from the diisocyanate (a) and the polyester polyol (B2) is diluted with butyl acetate and the solid content is adjusted to 64 mass% is not particularly limited, but is preferably 100mPa · s to 2000mPa · s, more preferably 150mPa · s to 1500mPa · s, and still more preferably 300mPa · s to 1000mPa · s, in terms of the amount of organic solvent and the number of functional groups. If the viscosity is not lower than the lower limit, the number of functional groups can be increased more sufficiently, while if it is not higher than the upper limit, the amount of the organic solvent can be further reduced.

As described in examples below, the viscosity can be measured at 25 ℃ using an E-type viscometer (manufactured by Tokimec).

[ isocyanate group content (NCO%) ]

When the polyisocyanate composition containing the polyisocyanate obtained from the diisocyanate (a) and the polyether polyol (B1) has an isocyanate group content (NCO%) of preferably 3.0% by mass or more and 20.0% by mass or less, more preferably 3.3% by mass or more and 19.0% by mass or less, and still more preferably 3.6% by mass or more and 18.0% by mass or less, from the viewpoint of performance when the polyisocyanate composition is diluted with butyl acetate and the solid content is adjusted to 75% by mass. When the NCO% is at least the lower limit, the performance of the resulting coating film is more excellent, while when the NCO% is at most the upper limit, the crosslinking density does not become too high, and a coating film which is less likely to crack is formed.

The NCO% can be determined by neutralizing the isocyanate group with an excess of 2N amine and back-titrating with 1N hydrochloric acid as described in examples below.

When the polyisocyanate composition containing the polyisocyanate obtained from the diisocyanate (a) and the polyester polyol (B2) is diluted with butyl acetate and the solid content is adjusted to 64% by mass, the isocyanate group content (NCO%) of the polyisocyanate composition is preferably 3.0% or more and 20.0% or less, more preferably 3.5% or more and 17.0% or less, still more preferably 4.0% or more and 14.0% or less, and particularly preferably 4.5% or more and 11.0% or less, from the viewpoint of performance when the polyisocyanate composition is formed into a coating film. When the NCO% is at least the lower limit, the performance of the resulting coating film is more excellent, while when the NCO% is at most the upper limit, the crosslinking density does not become too high, and a coating film which is less likely to crack is formed.

[ number average number of functional groups (fn) ]

The number-average functional group number (hereinafter, may be abbreviated as "fn") of the isocyanate group of the polyisocyanate composition containing the polyisocyanate obtained from the diisocyanate (a) and the polyester polyol (B2) is not particularly limited, and is preferably 3.0 or more and 10.0 or less, more preferably 3.2 or more and 9.0 or less, further preferably 3.4 or more and 8.0 or less, and particularly preferably 3.6 or more and 7.0 or less, from the viewpoints of curability and viscosity. If fn is not less than the lower limit, more sufficient curability can be obtained, and if fn is not more than the upper limit, viscosity does not become too high.

< uses of use >

The polyisocyanate composition of the present embodiment can be used as a raw material for coatings, inks, adhesives, injection molding materials, elastomers, foams, plastic materials.

Coating composition

The coating composition of the present embodiment contains a polyol as a main component and the above polyisocyanate composition as a curing agent component.

The coating composition of the present embodiment may contain, as a main component, another main component in addition to the polyol, and preferably contains only the polyol as a main component.

In addition, the coating composition of the present embodiment may contain, as a curing agent component, another curing agent component in addition to the polyisocyanate composition, and the coating composition of the present embodiment preferably contains only the polyisocyanate composition as a curing agent component.

The lower limit of the hydroxyl value of the polyol is 5mgKOH/g, preferably 10mgKOH/g, more preferably 15mgKOH/g, and still more preferably 20 mgKOH/g. On the other hand, the upper limit of the hydroxyl value of the polyol is 200mgKOH/g, preferably 160mgKOH/g, more preferably 120mgKOH/g, and still more preferably 80 mgKOH/g.

That is, the hydroxyl value of the polyol is 5mgKOH/g or more and 200mgKOH/g or less, preferably 10mgKOH/g or more and 160mgKOH/g or less, more preferably 15mgKOH/g or more and 120mgKOH/g or less, and still more preferably 20mgKOH/g or more and 80mgKOH/g or less.

By setting the hydroxyl value within the above range, a softer and tougher coating film can be obtained.

< polyol >

Examples of the polyol include acrylic polyols, polyester polyols, polyether polyols, polyolefin polyols, silicon-containing polyols, fluorine-containing polyols, polycarbonate polyols, epoxy resins, and alkyd polyols. These polyols may be used alone in 1 kind, or may be used in combination in 2 or more kinds. Further, as the polyol, urethane-modified acrylic polyol, urethane-modified polyester polyol, urethane-modified polyether polyol, or the like obtained by modifying an acrylic polyol, polyester polyol, polyether polyol, or the like with an aliphatic diisocyanate, an alicyclic diisocyanate, or a polyisocyanate obtained therefrom may also be used.

The polyol can also be produced by a known technique, and a method for producing a representative acrylic polyol, polyester polyol, or polyether polyol will be described below.

[ acrylic polyols ]

The acrylic polyol can be obtained by, for example, polymerizing only a polymerizable monomer having 1 or more active hydrogens in one molecule, or copolymerizing a polymerizable monomer having 1 or more active hydrogens in one molecule with another monomer copolymerizable with the polymerizable monomer as needed.

Examples of the polymerizable monomer having 1 or more active hydrogens in one molecule include the following monomers (i) to (vi). These may be used alone, or 2 or more of them may be used in combination. (i) Acrylic esters having active hydrogen such as 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxybutyl acrylate and the like. (ii) Methacrylic acid esters having active hydrogen such as 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-hydroxybutyl methacrylate, 3-hydroxypropyl methacrylate and 4-hydroxybutyl methacrylate. (iii) And polyvalent (meth) acrylates having active hydrogen such as (meth) acrylic monoesters of triols.

Examples of the triol include glycerin and trimethylolpropane. (iv) Monoethers of polyether polyols with the above (meth) acrylates having active hydrogens.

Examples of the polyether polyol include polyethylene glycol, polypropylene glycol, and polybutylene glycol. (v) An adduct of glycidyl (meth) acrylate with a monobasic acid.

Examples of the monobasic acid include acetic acid, propionic acid, and p-tert-butylbenzoic acid. (vi) An adduct obtained by ring-opening polymerization of an active hydrogen of the above-mentioned (meth) acrylate having an active hydrogen and a lactone.

Examples of the lactone include epsilon-caprolactone and gamma-valerolactone.

Examples of the other monomer copolymerizable with the polymerizable monomer include the following monomers (i) to (v). These may be used alone, or 2 or more of them may be used in combination. (i) (meth) acrylates such as methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-hexyl methacrylate, cyclohexyl methacrylate, lauryl methacrylate and glycidyl methacrylate; (ii) unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, and itaconic acid; (iii) unsaturated amides such as acrylamide, N-methylolacrylamide and diacetone acrylamide; (iv) vinyl monomers having a hydrolyzable silyl group such as vinyltrimethoxysilane, vinylmethyldimethoxysilane and γ - (meth) acryloylpropyltrimethoxysilane; (v) other polymerizable monomers such as styrene, vinyltoluene, vinyl acetate, acrylonitrile, and dibutyl fumarate

As a specific method for producing the acrylic polyol, for example, the acrylic polyol can be obtained by subjecting the above-mentioned monomers to solution polymerization in the presence of a known radical polymerization initiator such as a peroxide or an azo compound, and diluting the solution with an organic solvent or the like as necessary.

When the coating composition of the present embodiment contains a solvent having a large water content, the coating composition can be produced by a known method such as solution polymerization and conversion to an aqueous layer of the monomer, emulsion polymerization, or the like. In this case, water solubility or water dispersibility can be imparted to the acrylic polyol by neutralizing the acidic moiety of a carboxylic acid-containing monomer such as acrylic acid or methacrylic acid, or a sulfonic acid-containing monomer with amine or ammonia.

[ polyester polyols ]

The polyester polyol can be obtained by, for example, subjecting a dibasic acid alone or a mixture of 2 or more thereof to a condensation reaction with a polyol alone or a mixture of 2 or more thereof.

Examples of the dibasic acid include carboxylic acids such as succinic acid, adipic acid, dimer acid, maleic anhydride, phthalic anhydride, isophthalic acid, terephthalic acid, and 1, 4-cyclohexanedicarboxylic acid.

Examples of the polyhydric alcohol include ethylene glycol, propylene glycol, diethylene glycol, 1, 4-butanediol, neopentyl glycol, 1, 6-hexanediol, trimethylpentanediol, cyclohexanedimethanol, trimethylolpropane, glycerol, pentaerythritol, 2-hydroxymethylpropanediol, and ethoxylated trimethylolpropane.

As a specific method for producing the polyester polyol, for example, the condensation reaction can be carried out by mixing the above components and heating the mixture at about 160 ℃ to 220 ℃. Alternatively, for example, polycaprolactone obtained by ring-opening polymerization of a lactone such as epsilon-caprolactone using a polyol can be used as the polyester polyol.

[ polyether polyol ]

The polyether polyol can be obtained by any of the following methods (1) to (3), for example. (1) A process for producing a polyether polyol by random addition or block addition of an alkylene oxide to a polyhydric hydroxyl compound alone or a mixture thereof with a catalyst.

Examples of the catalyst include hydroxides of lithium, sodium, potassium, and the like, strongly basic catalysts, complex metal cyano compound complexes, and the like. Examples of the strongly basic catalyst include alkoxide, alkylamine, and the like, and examples of the complex metal cyano compound complex include metalloporphyrin, zinc hexacyanocobaltate complex, and the like.

Examples of the alkylene oxide include ethylene oxide, propylene oxide, butylene oxide, cyclohexene oxide, and styrene oxide. (2) A process for producing polyether polyols by reacting alkylene oxides with polyamine compounds.

Examples of the polyamine compound include ethylenediamine and the like.

Examples of the alkylene oxide include the same alkylene oxides as exemplified in (1). (3) A method of polymerizing acrylamide or the like using the polyether polyol obtained in (1) or (2) as a medium to obtain a so-called polymer polyol.

Examples of the polyhydric hydroxyl compound include the polyhydric hydroxyl compounds shown in the following (i) to (vi). (i) Diglycerol, ditrimethylolpropane, pentaerythritol, dipentaerythritol, and the like; (ii) sugar alcohol compounds such as erythritol, D-threitol, L-arabitol, ribitol, xylitol, sorbitol, mannitol, galactitol, and rhamnose alcohol; (iii) monosaccharides such as arabinose, ribose, xylose, glucose, mannose, galactose, fructose, sorbose, rhamnose, fucose and deoxyribose; (iv) disaccharides such as trehalose, sucrose, maltose, cellobiose, gentiobiose, lactose and melibiose; (v) trisaccharides such as raffinose, gentiotriose, melezitose and the like; (vi) tetrasaccharides such as stachyose

<NCO/OH>

In the coating composition of the present embodiment, the mixing ratio of the curing agent to the base compound can be expressed by the molar ratio of isocyanate groups to hydroxyl groups (NCO/OH). The lower limit of NCO/OH is preferably 0.1, more preferably 0.3, still more preferably 0.4, and particularly preferably 0.5. On the other hand, the upper limit of NCO/OH is preferably 5.0, more preferably 4.0, still more preferably 3.0, and particularly preferably 2.0.

That is, the NCO/OH is preferably 0.1 or more and 5.0 or less, more preferably 0.3 or more and 4.0 or less, further preferably 0.4 or more and 3.0 or less, and particularly preferably 0.5 or more and 2.0 or less.

When NCO/OH is in the above range, a stronger coating film can be formed.

< various additives >

The coating composition of the present embodiment may contain various additives used in the technical field, such as a coloring pigment, a dye, a silane coupling agent for improving adhesion of a coating film, an ultraviolet absorber, a curing accelerator, a light stabilizer, a matting agent, a coating film surface hydrophilic agent, a catalyst for accelerating curing, a drying improver, a leveling agent, an antioxidant, a plasticizer, a surfactant, and the like, in addition to the polyol and the polyisocyanate composition, according to the purpose and the use, within a range not impairing the effect of the present invention.

The coloring pigment may be an inorganic pigment or an organic pigment. Examples of the inorganic pigment include carbon black and titanium oxide having good weather resistance. Examples of the organic pigment include phthalocyanine blue, phthalocyanine green, quinacridone red, indanthrene orange, and isoindolinone yellow.

Examples of the silane coupling agent include 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, ureidopropyltriethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 2- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, methyltriethoxysilane, and methyltrimethoxysilane.

Examples of the ultraviolet absorber include benzophenone-based, benzotriazole-based, triazine-based, and cyanoacrylate-based ultraviolet absorbers.

Examples of the light stabilizer include hindered amine light stabilizers and the like, and specific commercially available products include, for example, ADEKASTAB LA62 and ADEKASTAB LA67 (both trade names, manufactured by Adeka Argus Chemical company); tinuvin 292, Tinuvin 144, Tinuvin 123 and Tinuvin 440 (trade names, all manufactured by Ciba Specialty Chemicals Co., Ltd.); sanol LS765 (trade name, manufactured by Sankyo Lifetech).

Examples of the matting agent include ultrafine synthetic silica, and when the matting agent is used, a coating film having an elegant semi-gloss and a mat finish can be formed.

The coating surface hydrophilizing agent is preferably a silicate compound. When a coating film is produced using the coating composition of the present embodiment by containing a silicate compound, the surface of the coating film is rendered hydrophilic, and the linear contamination resistance against rain is exhibited. Since the silicate compound reacts with a hydroxyl group, it is preferably added to the polyisocyanate composition as a curing agent component when it is mixed in advance. Alternatively, when the polyol as the main component is mixed with the polyisocyanate composition as the curing agent component, the polyol and the polyisocyanate composition may be mixed at the same time.

Examples of the silicate compound include tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, tetra-isopropoxysilane, tetra-n-butoxysilane, tetra-isobutoxysilane, tetra-t-butoxysilane, dimethoxydiethoxysilane, tetraphenoxysilane, and condensates thereof. Among them, as the silicate compound, a condensate of tetramethoxysilane or a condensate of tetraethoxysilane is preferable because hydrophilicity is easily exhibited on the surface of a coating film when the coating film is formed.

The catalyst for accelerating curing is not limited to the following catalysts, and examples thereof include metal salts and tertiary amines.

Examples of the metal salt include dibutyltin dilaurate, tin 2-ethylhexanoate, zinc 2-ethylhexanoate, and cobalt salts.

Examples of the tertiary amine include triethylamine, pyridine, picoline, benzyldimethylamine, N-dimethylcyclohexylamine, N-methylpiperidine, pentamethyldiethylenetriamine, N '-ethanopiperazine, and N, N' -dimethylpiperazine.

Examples of the dryness improver include CAB (cellulose acetate butyrate) and NC (nitrocellulose).

[ leveling agent ]

The leveling agent is not particularly limited, and examples thereof include silicones, AEROSILs, waxes, stearates, and polysiloxanes.

[ plasticizer ]

The plasticizer is not particularly limited, and examples thereof include phthalic acid esters, phosphoric acid esters, fatty acid esters, pyromellitic acid esters, epoxy plasticizers, polyether plasticizers, liquid rubbers, and non-aromatic paraffin oils.

Examples of the phthalic acid esters include dioctyl phthalate, dibutyl phthalate, diethyl phthalate, butyl benzyl phthalate, di-2-ethylhexyl phthalate, diisodecyl phthalate, diundecyl phthalate, and diisononyl phthalate.

Examples of the phosphate esters include tricresyl phosphate, triethyl phosphate, tributyl phosphate, tris (-2-ethylhexyl) phosphate, tris (methylhexyl) phosphate, tris (chloroethyl) phosphate, and tris (dichloropropyl) phosphate.

Examples of the fatty acid esters include trimellitic esters, dipentaerythritol esters, dioctyl adipate, dimethyl adipate, di (2-ethylhexyl) azelate, dioctyl sebacate, di (2-ethylhexyl) sebacate, and methyl acetylricinoleate. Examples of trimellitates include octyl trimellitate and isodecyl trimellitate.

Examples of the pyromellitic acid ester include octyl pyromellitate and the like.

Examples of the epoxy plasticizer include epoxidized soybean oil, epoxidized linseed oil, and epoxidized fatty acid alkyl ester.

Examples of the polyether plasticizer include adipic acid ether ester and polyether.

Examples of the liquid rubber include liquid NBR, liquid acrylic rubber, and liquid polybutadiene.

[ surfactant ]

Examples of the surfactant include known anionic surfactants, cationic surfactants, and amphoteric surfactants.

< method for producing coating composition >

The coating composition of the present embodiment is useful as a solvent coating composition, and can be obtained by the production method described below.

In the case where the coating composition of the present embodiment is a solvent-based coating composition, for example, first, various additives are added to a polyol or a solvent dilution thereof as a main agent as necessary, and the polyisocyanate composition described above as a curing agent is added to the resultant. Then, a solvent is further added as necessary to adjust the viscosity. Next, the solvent-based coating composition can be obtained by stirring by hand or using a stirring machine such as MAZELAR.

The mixing order of the main component containing the polyol as the main component, the curing agent component containing the polyisocyanate composition as the main component, and the various additives is not particularly limited, and the mixing may be performed in the following order, for example.

1) Mixing a curing agent component into a main agent component in which various additives are previously mixed at a coating site;

2) mixing the main agent component and the curing agent component at a coating site, and then mixing various additives;

3) to the main component in which various additives are previously mixed, a curing agent component in which various additives are previously mixed is mixed at the coating site.

< uses of use >

The Coating composition of the present embodiment is not limited to the following applications, and can be used as a Coating material for, for example, spray Coating, air jet Coating, brush Coating, Coating by a dipping method, roll Coating, curtain Coating, Bell-Type Coating (Bell-Type Coating), electrostatic Coating, or the like.

The coating composition of the present embodiment is also useful as a coating material for a molded article made of a material such as metal (e.g., steel sheet, surface-treated steel sheet, etc.), plastic, wood, a film, or an inorganic material, and is particularly suitable as a coating material for metal or plastic.

The coating composition of the present embodiment is suitable for, for example, architectural coatings, heavy duty anticorrosive coatings, automotive coatings, coatings for information appliances such as personal computers and mobile phones, and is particularly suitable as a top layer clear coating for architectural structures, automobile bodies, automotive metal parts, automotive plastic parts, metal parts for information appliances, and plastic parts for information appliances.

(film coating)

The coating film of the present embodiment is obtained by curing the above coating composition, has stable quality, and is excellent in water resistance, weather resistance, bendability, and adhesion.

The coating film of the present embodiment is obtained by curing the above coating composition, and has stable quality and excellent water resistance, weather resistance and stretchability.

< method for producing coating film >

The method for producing a coating film of the present embodiment is a method including a step of curing the coating composition.

The coating film of the present embodiment can be produced by applying the coating composition to a substrate by a known coating method such as spray coating, air jet coating, brush coating, coating by a dipping method, roll coating, curtain coating, bell jar coating, or electrostatic coating, and then curing the coating composition.

The substrate may be the same as the molded article made of the raw material exemplified in "< application of coating composition >".

Examples

The present embodiment will be described in more detail below by showing specific examples and comparative examples, but the present embodiment is not limited to the following examples and comparative examples mainly without departing from the gist thereof.

[ Property 1] (A/B, C/B, C/(A + C) and B/(A + B + C))

The obtained polyisocyanate composition was reacted with Biospin Avance600 (trade name) manufactured by Bruker¹³C-NMR measurement. Specific measurement conditions are as follows.

(measurement conditions)

¹³C-NMR apparatus: AVANCE600 (manufactured by Bruker corporation)

Cryoprobe (manufactured by Bruker Co., Ltd.)

CryoProbe (registered trademark)

CPDUL

600S3-C/H-D-05Z

Resonance frequency: 150MHz

Concentration: 60 wt/vol%

Displacement reference: CDCl₃(77ppm)

And (3) accumulating times: 10000 times

Pulse program: zgpg30 (proton complete decoupling, standby time 2 seconds)

The integrated value of the following signals was divided by the measured carbon number to determine the respective molar ratios of allophanate groups, isocyanurate groups and urethane groups. Next, A/B, C/B, C/(A + C) and B/(A + B + C) were calculated, where A represents the number of moles of allophanate groups, B represents the number of moles of isocyanurate groups and C represents the number of moles of urethane groups.

Isocyanurate group: (integrated value near 148.6 ppm) ÷ 3

A carbamate group: (integrated value near 156.5 ppm) ÷ 1

Allophanate group: (integrated value near 154 ppm) ÷ 1

[ Property 2] (average number of isocyanate functional groups (average NCO number))

The average number of functional groups (average NCO number) of isocyanate was determined by the following formula using the polyisocyanate composition before the addition of n-butyl acetate as a sample.

Average isocyanate (NCO) number ═ Mn × NCO% × (0.01)/42

In the formula, "NCO%" represents the content of isocyanate group, and the value obtained in "Property 4" described later was used. "Mn" represents a number average molecular weight, and is determined as a polystyrene-based molecular weight by GPC measurement under the measurement conditions shown below.

(measurement conditions)

The device comprises the following steps: HLC-8320GPC (TOSOH)

Column: TSKgelSuperH 2500X 1 root (TOSOH)

TSKgelSuperH 4000X 1 root (TOSOH)

TSKgelSuperH 5000X 1 root (TOSOH)

TSKgelSuperH 6000X 1 root (TOSOH)

Carrier: tetrahydrofuran (THF)

Flow rate: 0.6 mL/min

Sample concentration: 1.0% by mass

Injection amount: 20 μ L

Temperature: 40 deg.C

The detection method comprises the following steps: differential refractometer

[ Property 3] (viscosity at 25 ℃ C.)

The viscosity was measured at 25 ℃ with an E-type viscometer (manufactured by Tokimec Co., Ltd.). A standard rotor (1 ° 34' xr 24) was used. The rotational speeds are as follows.

(rotational speed)

100r.p.m. (less than 128 mPas)

50r.p.m. (in the case of 128 mPas or more and less than 256 mPas)

20r.p.m. (256 mPas or more and less than 640 mPas)

10r.p.m. (640 mPas or more and less than 1280 mPas)

5r.p.m. (1280 mPas or more and less than 2560 mPas)

2.5r.p.m. (2560 mPas or more and less than 5120 mPas)

1r.p.m. (5120 mPas or more and less than 10240 mPas)

0.5r.p.m. (10240 mPas or more and less than 20480 mPas)

[ Property 4] (isocyanate group content (NCO%))

The NCO% was determined by neutralizing the isocyanate group with an excess of 2N amine and back-titrating with 1N hydrochloric acid.

[ Property 5] (HDI monomer concentration)

The number average molecular weight based on polystyrene was measured by GPC measurement under the measurement conditions indicated by "property 2" above. Subsequently, the peak area% of the molecular weight (168) corresponding to the unreacted HDI monomer was calculated as the HDI monomer concentration.

< method for evaluating coating film >

Using each polyisocyanate composition, a coating composition was produced as shown below, and evaluated.

Production example 1 production of coating composition

First, an acrylic polyol (product name, "Setalux 1903", manufactured by Allnex corporation), a resin solid content concentration of 75%, and a hydroxyl value of 150 mgKOH/resin g were compounded with each polyisocyanate composition so that the equivalent ratio of hydroxyl groups to isocyanate groups became 1: 1. Thereafter, the coating viscosity was adjusted to 20 seconds in terms of Ford cup No.4 with butyl acetate to obtain each coating composition.

[ evaluation 1-1-1] (Water resistance (room temperature))

Each coating composition was applied to a glass plate so that the dry film thickness became 30 μm, and the plate was left at room temperature for 48 minutes to be cured to obtain each coating film. The coating film was kept at 60 ℃ and 87% humidity for 72 hours. Thereafter, the mixture was left at room temperature for 60 minutes. The coating film after the test was observed by visual observation. The water resistance (room temperature) of each coating film was evaluated according to the evaluation criteria shown below. The evaluation results are shown in tables 1-1 to 1-4.

(evaluation criteria)

Very good: no whitening and no granular appearance were observed

Good: whitening, graininess at 1 or 2 was observed

And (delta): whitening and particulates at 3 or more and 5 or less were observed

X: whitening and particulate matter at 6 or more spots was observed

[ evaluation 1-1-2] (Water resistance (Low temperature))

Each coating composition was applied to a glass plate so that the dry film thickness became 30 μm, and the plate was left at 5 ℃ for 24 hours to be cured to obtain each coating film. The coating film was immersed in water and kept at 5 ℃ for 24 hours. Thereafter, the mixture was left at room temperature for 60 minutes. The 60 ° gloss values of the coating films before and after the test were measured, and the percentage of the ratio of the 60 ° gloss value of the coating film after the test divided by the 60 ° gloss value of the coating film before the test was calculated as the gloss retention ratio. The water resistance (low temperature) of each coating film was evaluated according to the evaluation criteria shown below. The evaluation results are shown in tables 1-1 to 1-4.

(evaluation criteria)

Very good: the gloss retention ratio is 93% or more

Good: the gloss retention ratio is more than 91% and less than 93%

And (delta): the gloss retention ratio is more than 89% and less than 91%

X: the gloss retention is less than 89%

[ evaluation 1-2] (weather resistance)

Each coating composition was applied to a white enamel-coated plate by an applicator so that the dried film thickness became 40 μm, and the coating was cured at 20 ℃ and 63% humidity for 1 week, and then the coated plate was evaluated for weather resistance. As the weather resistance, a Dewpanel weather meter (manufactured by Suga Test Instruments) was used. Evaluation conditions irradiation illuminance of 30W/m in accordance with JIS D0205²And a cycle operation in which the panel temperature was 60 ℃, the irradiation time and the condensation time were 4 hours each. The water resistance of each coating film was evaluated according to the evaluation criteria shown below. The evaluation results are shown in tables 1-1 to 1-4.

(evaluation criteria)

Very good: the gloss retention at the time of exposure for 1200 hours is 80% or more

Good: the gloss retention at the time of exposure for 1200 hours is 70% or more and less than 80%

X: the gloss retention at the time of exposure time of 1200 hours is less than 70%

[ evaluation 1-3] (bendability)

Regarding the bendability, the minimum diameter at which breakage and peeling do not occur was described in each coating composition by winding a PET film having a cured film formed thereon (the cured film being the outer side) on a mandrel bar having a diameter of 2mm, 3mm, 4mm, 5mm, 6mm and 8mm in accordance with the mandrel test (JIS K5600-5-1). Here, when the mandrel diameter was 2mm, a test was also performed in which the film was bent without the mandrel, and when the film was not broken, the mandrel was not present, and thus the film was evaluated as 0 mm. The evaluation results are shown in tables 1-1 to 1-4.

[ evaluation 1-4] (adhesion)

Each coating composition was applied to a polypropylene resin test piece cleaned with a neutral detergent so that the dry film thickness became 30 μm, and the coating film was cured after leaving at room temperature for 48 hours to obtain each coating film. The peel adhesion test of the transparent adhesive tape was carried out on the checkerboard of the test piece in accordance with JIS K-5400. The surface of the test piece was scratched with a cutter to form 100 checkerboards of 2mm square. After the transparent adhesive tape is adhered to the surface of the test piece, the transparent adhesive tape is quickly peeled off from the surface of the test piece, and the number of the indelible chessboards is counted. The adhesion was evaluated according to the following evaluation criteria. The more the number of non-peeled squares out of the 100 squares is, the better the evaluation is. The evaluation results are shown in tables 1-1 to 1-4.

(evaluation criteria)

5: 100/100 (not peeling)

4: 90/100 or more and 99/100 or less

3: 70/100 or more and 89/100 or less

2: 50/100 or more and 69/100 or less

1: 0/100 or more and 49/100 or less

< Synthesis of polyisocyanate >

[ Synthesis example 1-1] (Synthesis of polyisocyanate A1-1)

Make nitrogen atmosphere in the four-necked flask that will install mixer, thermometer, reflux condenser pipe, nitrogen gas insufflation pipe and dropping funnel, input HDI: 1000g and 2-ethylhexanol: 100g, carbamation was carried out at 90 ℃ for 1 hour with stirring. As allophanation and isocyanation catalysts, 1g of a solution prepared by diluting tetramethylammonium decanoate with isobutanol to 5% by mass was added to conduct an isocyanation reaction. When the refractive index of the reaction solution increased to 0.015, phosphoric acid was added to stop the reaction. After the reaction solution was filtered, the reaction solution was purified 2 times at 160 ℃ under 0.2Torr in a thin film evaporator to obtain polyisocyanate A1-1. The polyisocyanate A1-1 had a viscosity of 400 mPas (25 ℃ C.), an NCO content of 17.7% by mass and an HDI monomer concentration of 0.11% by mass.

[ Synthesis examples 1-2] (Synthesis of polyisocyanate A1-2)

The same apparatus as in Synthesis example 1-1 was charged with HDI: 1000g, the temperature in the reactor was maintained at 80 ℃ for 2 hours with stirring. Thereafter, 1g of a solution prepared by diluting tetramethylammonium decanoate to 5 mass% with isobutanol was added as an isocyanuric acid esterification catalyst, and an isocyanuric acid esterification reaction was performed. When the refractive index of the reaction solution increased to 0.012, phosphoric acid was added to stop the reaction. After the reaction solution was filtered, unreacted HDI was removed by the same method as in Synthesis example 1-1 to obtain polyisocyanate A1-2. The polyisocyanate A1-2 thus obtained had a viscosity of 1300 mPas (25 ℃ C.), an NCO content of 23.1% by mass and an HDI monomer concentration of 0.11% by mass.

[ Synthesis examples 1-3] (Synthesis of polyisocyanate A1-3)

The same apparatus as in Synthesis example 1-1 was charged with HDI: 1000g and 2-ethylhexanol: 30g, carbamation was carried out at 90 ℃ for 1 hour with stirring. As allophanation and isocyanation catalysts, 1g of a solution prepared by diluting tetramethylammonium decanoate with isobutanol to 5% by mass was added to conduct an isocyanation reaction. When the refractive index of the reaction solution increased to 0.012, phosphoric acid was added to stop the reaction. After the reaction solution was filtered, unreacted HDI was removed by the same method as in Synthesis example 1-1 to obtain polyisocyanate A1-3. The polyisocyanate A1-3 had a viscosity of 500 mPas (25 ℃ C.), an NCO content of 20.6 mass% and an HDI monomer concentration of 0.11 mass%.

[ Synthesis examples 1 to 4] (Synthesis of polyisocyanate A1-4)

The same apparatus as in Synthesis example 1-1 was charged with HDI: 1000g and 2-ethylhexanol: 30g, carbamation was carried out at 80 ℃ for 1 hour with stirring. As allophanation and isocyanation catalysts, 1g of a solution prepared by diluting tetramethylammonium decanoate with isobutanol to 5% by mass was added to conduct an isocyanation reaction. When the refractive index of the reaction solution increased to 0.008, phosphoric acid was added to stop the reaction. After the reaction solution was filtered, unreacted HDI was removed by the same method as in Synthesis example 1-1 to obtain polyisocyanate A1-4. The polyisocyanate A1-4 had a viscosity of 400 mPas (25 ℃ C.), an NCO content of 20.4 mass% and an HDI monomer concentration of 0.11 mass%.

Synthesis examples 1 to 5 Synthesis of polyisocyanate A1-5

The same apparatus as in Synthesis example 1-1 was charged with HDI: 1000g and 2-ethylhexanol: 78g, carbamation was carried out at 130 ℃ for 1 hour with stirring. As an allophanatization catalyst, 0.35g of a 20% mineral spirit solution of zirconyl 2-ethylhexanoate was added. After 60 minutes, 0.47g of a 39% ethanol solution (trade name "phosphoric acid (105%)" manufactured by taiping chemical industries, inc.) as a solid content of pyrophosphoric acid was added to the reaction solution at a time when the refractive index of the reaction solution had risen to 0.0055, and the reaction was stopped. Next, unreacted HDI was removed by the same method as in Synthesis example 1-1 to obtain polyisocyanate A1-5. The polyisocyanate A1-5 had a viscosity of 100 mPas (25 ℃ C.), an NCO content of 17.4% and a HDI monomer concentration of 0.11% by mass.

[ Synthesis examples 1 to 6] (Synthesis of polyisocyanate A1-6)

The same apparatus as in Synthesis example 1-1 was charged with HDI: 1000g and 44g of 1, 4-butanediol were kept at a reactor internal temperature of 160 ℃ for 1 hour with stirring. Thereafter, the reaction solution was filtered, and then unreacted HDI was removed by the same method as in Synthesis example 1-1 to obtain polyisocyanate A1-6. The polyisocyanate A1-6 had a viscosity of 600 mPas (25 ℃ C.), an NCO content of 19.2% by mass and an HDI monomer concentration of 0.2% by mass.

< production of polyisocyanate composition >

Example 1-1 (production of polyisocyanate composition P1-a 1)

The polyisocyanate A1-3 obtained in Synthesis examples 1-3 was charged into the same apparatus as in Synthesis example 1-1: 50g of polyether polyol B1-2 (product name: AGC, EXCENOL 230, molecular weight: 3000) and 0.01g of 2-ethylhexyl phosphate (product name: JP-508, product name: North City chemical industry). Subsequently, the mixed solution was urethanized at 120 ℃ for 4 hours under stirring, and then a hindered amine light stabilizer (product name "Tinuvin 765" from BASF Japan, 0.1g, and 33g of n-butyl acetate as a diluting solvent were added thereto to obtain polyisocyanate compositions P1-a1, which were transparent liquids having a viscosity of 700 mPas (25 ℃) and an NCO content of 6.2 mass%, from polyisocyanate compositions P1-a1..

[ examples 1-2 to 1-17 and comparative examples 1-1 to 1-4, 1-6] (production of polyisocyanate compositions P1-a 2to P1-a17 and P1-b1 to P1-b4 and P1-b 6)

Polyisocyanate compositions P1-a 2-P1-a 17, P1-b 1-P1-b 4 and P1-b6 were obtained in the same manner as in example 1-1, except that the formulations shown in tables 1-1 to 1-4 were used.

In tables 1-1 to 1-4, the polyether polyols are shown below.

B1-1: product of AGC, "EXCENOL 840" (trade name), number average molecular weight 6500

B1-2: product of AGC, "EXCENOL 230" (trade name), number average molecular weight 3000

B1-3: product of AGC, "EXCENOL 1030" (trade name), number average molecular weight 1000

B1-4: "EXCENOL 1020" (trade name) manufactured by AGC corporation, number average molecular weight 1000

B1-5: manufactured by Gekko Korea chemical, PTG1000SN (trade name), number average molecular weight 1000

Comparative examples 1 to 5 production of polyisocyanate composition P1-b5

The same apparatus as in Synthesis example 1-1 was charged with HDI: 500g and 150g of polyether polyol B1-1 (product of AGC, "EXCENOL 840" (trade name), molecular weight 6500) were subjected to urethanization at 90 ℃ for 2 hours under stirring. 0.02g of tetramethylammonium octanoate was added as an isocyanurated catalyst at 90 ℃. After 4 hours, when the refractive index of the reaction solution increased to 0.01, 0.1g of phosphoric acid was added to stop the reaction. Purification was performed twice at 150 ℃ and 2Torr using a thin film evaporator to obtain a polyisocyanate composition P1-b 5. The obtained polyisocyanate composition P1-b5 had a viscosity of 200 mPas (25 ℃ C.), an NCO content of 11.4% by mass and an HDI monomer concentration of 0.11% by mass.

The obtained polyisocyanate compositions were used to evaluate water resistance, weather resistance, flexibility and adhesion by the methods described above. The results are shown in tables 1-1 to 1-4.

[ tables 1-1]

[ tables 1-2]

[ tables 1 to 3]

[ tables 1 to 4]

As can be seen from tables 1-1 to 1-4: by using the polyisocyanate compositions P1-a1 to P1-a17 (examples 1-1 to 1-17), a coating film excellent in water resistance, weather resistance, bendability and adhesion can be obtained.

Further, among the polyisocyanate compositions P1-a1 to P1-a17 (examples 1-1 to 1-17), the polyisocyanate compositions P1-a1 to P1-a7 and P1-a9 to P1-a16 (examples 1-1 to 1-7 and 1-9 to 1-16) having an average NCO number of 3.1 or more were more excellent in water resistance at normal temperature and low temperature when they were formed into coating films. Further, polyisocyanate compositions P1-a 1-P1-a 6, P1-a 10-P1-a 12 and P1-a17, each having an average NCO number of 3.5 or more, a viscosity of 400 to 2200 mPas inclusive and an NCO content of 3.6 to 11.5% by mass, are particularly excellent in water resistance at ordinary and low temperatures when they are formed into a coating film. In this regard, it can be assumed that: the polyisocyanate used has an average NCO number of 3.5 or more, a viscosity in an appropriate numerical range, and an NCO content ratio indicating the ratio of isocyanate groups capable of forming a bond with a hydroxyl group of the main agent in an appropriate numerical range, and therefore, the formed coating film has a good balance between elasticity and crosslinking density, and can impart flexibility to the coating film, and therefore, the coating film is particularly excellent in water resistance.

Furthermore, the polyisocyanate compositions P1-a 1-P1-a 4, P1-a 6-P1-a 7, P1-a 10-P1-a 12 and P1-a17 (examples 1-1 to 1-4, 1-6 to 1-7, 1-10 to 1-12 and 1-17) having an A/B value of 1.00 or less and a C/B value of 1.10 or less are particularly excellent in weather resistance when they are formed into a coating film.

Furthermore, the polyisocyanate compositions P1-a 4-P1-a 6 and P1-a 8-P1-a 16 (examples 1-4 to 1-6 and 1-8 to 1-16) having an A/B ratio of 1.00 or more or a C/B ratio of 0.50 or more were particularly excellent in adhesion when they were formed into coating films.

Furthermore, the polyisocyanate compositions P1-a 1-P1-a 6 and P1-a 8-P1-a 16 (examples 1-1 to 1-6 and 1-8 to 1-16) having an A/B value of 0.36 or more or a C/B value of 0.25 or more were particularly excellent in bendability in the case of forming a coating film.

On the other hand, when the polyisocyanate compositions P1-b1 to P1-b6 (comparative examples 1-1 to 1-6) were used, a coating film excellent in all of water resistance, weather resistance, flexibility and adhesiveness was not obtained.

[ evaluation 2-1] Water resistance

Each coating composition was applied to a glass plate so that the dry film thickness became 30 μm, left to stand at room temperature for 15 minutes, and then cured in an oven at 60 ℃ for 120 minutes to obtain each coating film. After cooling at room temperature, the coating film was kept at 60 ℃ and 87% humidity for 72 hours. Thereafter, the film was left at room temperature for 60 minutes, and the film after the test was visually observed. The water resistance of each coating film was evaluated according to the evaluation criteria shown below. The evaluation results are shown in Table 2-1.

(evaluation criteria)

Very good: no whitening and no granular appearance were observed

Good: whitening, graininess at 1 or 2 was observed

X: whitening and graininess at 3 places or more was observed

[ evaluation 2-2] weather resistance

Each coating composition was applied to a white enamel-coated plate by an applicator so that the dried film thickness became 40 μm, and the coating was cured at 20 ℃ and 63% humidity for 1 week, and then the coated plate was evaluated for weather resistance. The weather resistance was evaluated by using a Dewpanel weather Meter (manufactured by Suga Test Instruments Co., Ltd.). Evaluation conditions irradiation illuminance of 30W/m in accordance with JIS D0205²And a cycle operation in which the panel temperature was 60 ℃, the irradiation time and the condensation time were 4 hours each. The water resistance of each coating film was evaluated according to the evaluation criteria shown below. The evaluation results are shown in Table 2-1.

(evaluation criteria)

Very good: the gloss retention at the time of exposure for 1200 hours is 80% or more

Good: the gloss retention at the time of exposure for 1200 hours is 70% or more and less than 80%

X: the gloss retention at the time of exposure time of 1200 hours is less than 70%

[ evaluation 2-3] stretchability (film elongation)

Each coating composition was applied by an applicator so that the film thickness after drying became 50 μm. After the coating, the coating was cured at 23 ℃ and 50% humidity for 7 days to obtain each coating film. The resulting coating film was subjected to a tensile test. The elongation of the coating film was measured at a tensile rate of 20 mm/min and at a nip interval of 20mm using a tensile tester (AGS 500G, manufactured by Shimadzu corporation) under conditions of a temperature of 23 ℃ and a humidity of 50%. The water resistance of each coating film was evaluated according to the evaluation criteria shown below. The evaluation results are shown in Table 2-1.

(evaluation criteria)

Very good: the elongation of the coating film is more than 150 percent

Good: the elongation of the coating film is more than 100 percent and less than 150 percent

X: the elongation of the coating film is more than 0 percent and less than 100 percent

< Synthesis of polyisocyanate >

Synthesis example 2-1 Synthesis of polyisocyanate A2-1

Make nitrogen atmosphere in the four-necked flask that will install mixer, thermometer, reflux condenser pipe, nitrogen gas insufflation pipe and dropping funnel, input HDI: 1000g, the temperature in the reactor was maintained at 80 ℃ for 2 hours with stirring. Thereafter, 1g of a solution prepared by diluting tetramethylammonium decanoate to 5 mass% with isobutanol was added as an isocyanurated catalyst to conduct an isocyanurated reaction. When the refractive index of the reaction solution increased to 0.012, phosphoric acid was added to stop the reaction. After the reaction solution was filtered, it was purified 2 times at 160 ℃ and 0.2Torr in a thin film evaporator to obtain polyisocyanate A2-1. The obtained polyisocyanate A2-1 had a viscosity of 1300 mPas (25 ℃ C.), an NCO content of 23.1 mass% and an HDI monomer concentration of 0.11 mass%.

Synthesis example 2-2 Synthesis of polyisocyanate A2-2

The same apparatus as in Synthesis example 2-1 was charged with HDI: 1000g of 2-ethylhexanol and 30g of 2-ethylhexanol were subjected to urethanization reaction at 90 ℃ for 1 hour with stirring. As allophanation and isocyanurate catalysts, 1g of a solution prepared by diluting tetramethylammonium decanoate with isobutanol to 5% by mass was added to conduct an isocyanurate reaction. When the refractive index of the reaction solution increased to 0.012, phosphoric acid was added to stop the reaction. After the reaction solution was filtered, unreacted HDI was removed by the same method as in Synthesis example 2-1 to obtain polyisocyanate A2-2. The polyisocyanate A2-2 had a viscosity of 500 mPas (25 ℃ C.), an NCO content of 20.6 mass% and an HDI monomer concentration of 0.11 mass%.

Synthesis examples 2to 3 Synthesis of polyisocyanate A2-3

The same apparatus as in Synthesis example 2-1 was charged with HDI: 1000g and 78g of 2-ethylhexanol were subjected to urethanization reaction with stirring at 130 ℃ for 1 hour. As an allophanatization catalyst, 0.35g of a 20% mineral spirit solution of zirconyl 2-ethylhexanoate was added. After 60 minutes, 0.47g of a 39% ethanol solution (trade name "phosphoric acid (105%)" manufactured by taiping chemical industries, inc.) as a solid content of pyrophosphoric acid was added to the reaction solution at a time when the refractive index of the reaction solution had risen to 0.0055, and the reaction was stopped. Next, unreacted HDI was removed by the same method as in Synthesis example 2-1 to obtain polyisocyanate A2-3. The polyisocyanate A2-3 thus obtained was a transparent liquid having a viscosity of 100 mPas, an NCO content of 17.4% and an HDI monomer concentration of 0.11% by mass.

< production of polyisocyanate composition >

EXAMPLE 2-1 preparation of polyisocyanate composition P2-a1

Into the same apparatus as in Synthesis example 2-1, polyisocyanate A2-1 obtained in Synthesis example 2-1 was charged: 100g, 60g of polyester polyol B2-1 (product name, "POLYLIGHT OD-X-2722" (trade name), molecular weight 2000) and 0.01g of 2-ethylhexyl phosphate (product name, "JP-508" from North City chemical industries, Ltd.). Subsequently, the mixed solution was subjected to urethanization reaction at 110 ℃ for 4 hours under stirring, and 90g of n-butyl acetate was added as a diluting solvent to obtain a polyisocyanate composition P2-a 1. The polyisocyanate composition P2-a1 was a transparent liquid and had a viscosity of 650 mPas and an NCO content of 8.3%. Further, using the polyisocyanate composition P2-a1 thus obtained, water resistance, weather resistance and elongation of the coating film were evaluated by the methods described above. The results are shown in Table 2-1.

[ examples 2-7 and comparative examples 2-1-2-4, 2-6] production of polyisocyanate compositions P2-a 2-P2-a 7, P2-b 1-P2-b 4, and P2-b6

Polyisocyanate compositions P2-a 2-P2-a 7, P2-b 1-P2-b 4 and P2-b6 were obtained in the same manner as in example 2-1, except that the formulations shown in Table 2-1 were used. The obtained polyisocyanate compositions were evaluated for water resistance, weather resistance and elongation of coating film by the methods described above. The results are shown in Table 2-1. In Table 2-1, "polyester polyol B2-2" represents the following commercial products.

Polyester polyol B2-2: POLYLIGHT OD-X-2542C (trade name) manufactured by DIC corporation, molecular weight 850

Comparative examples 2to 5 production of polyisocyanate composition P2-b5

The same apparatus as in Synthesis example 2-1 was charged with HDI: 562g and 115g of polyester polyol B2-3 (polycaprolactone polyol, xylonite, product of "Placcel 305" (trade name), molecular weight 550) were subjected to urethanization at 100 ℃ for 1 hour under stirring. Then, after removing unreacted HDI by the same method as in Synthesis example 2-1, 90g of n-butyl acetate was added as a diluting solvent to obtain polyisocyanate composition P2-B5 (composition (unit g): HDI/polyester polyol B2-3/n-butyl acetate 45/115/90). The polyisocyanate composition P2-b5 was a transparent liquid and had a viscosity of 100 mPas and an NCO content of 7.4%. Further, using the polyisocyanate composition P2-b5 thus obtained, water resistance, weather resistance and elongation of the coating film were evaluated by the methods described above. The results are shown in Table 2-1.

[ Table 2-1]

As can be confirmed from Table 2-1: by using the polyisocyanate compositions P2-a1 to P2-a7 (examples 2-1 to 2-7), a coating film excellent in water resistance, weather resistance and elongation (elongation of coating film) can be obtained.

In the polyisocyanate compositions P2-a 1-P2-a 7 (examples 2-1 to 2-7), when C/(A + C) is 0.57 or more, a tendency to be more excellent in water resistance when formed into a coating film is observed, when C/(A + C) is 0.93 or more, a tendency to be more excellent in stretchability is observed in addition to water resistance when formed into a coating film, when B/(A + B + C) is 0.51 or more, and when B/(A + B + C) is 0.73 or more, a tendency to be more excellent in weather resistance is observed in addition to water resistance when formed into a coating film.

On the other hand, when the polyisocyanate compositions P2-b1 to P2-b6 (comparative examples 2-1 to 2-6) were used, a coating film excellent in all of water resistance, weather resistance and elongation (elongation of coating film) was not obtained.

Industrial applicability

The polyisocyanate composition according to the present embodiment can provide a polyisocyanate composition having excellent water resistance, weather resistance, bendability and adhesion when formed into a coating film. Further, according to the polyisocyanate composition of the present embodiment, a polyisocyanate composition excellent in water resistance, weather resistance and stretchability when formed into a coating film can be provided. The polyisocyanate composition of the present embodiment can be used as a raw material for coatings, inks, adhesives, injection molding materials, elastomers, foams, plastic materials. The coating composition of the present embodiment is suitable for architectural coatings, heavy duty anticorrosive coatings, automotive coatings, coatings for information appliances, and coatings for information devices such as personal computers and cellular phones.

Claims (7)

1. A polyisocyanate composition comprising a polyisocyanate and containing allophanate groups, isocyanurate groups and urethane groups,

when the number of moles of the allophanate groups is A, the number of moles of the isocyanurate groups is B and the number of moles of the urethane groups is C, the ratio of C/B is 0.06 to 5.50,

the polyisocyanate is obtained from (A) at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates and at least one polyol selected from the group consisting of (B1) polyether polyols having oxypropylene groups with a number average molecular weight of 400 to 10000 or less and (B2) polyester polyols having a number average molecular weight of 250 to 4000 or more derived from 2-to 3-membered alcohols and epsilon-caprolactone,

C/(A + C) is 0.45-0.99, and B/(A + B + C) is 0.40-0.90.

2. The polyisocyanate composition according to claim 1, wherein the polyisocyanate is a polyisocyanate obtained from (A) at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates and (B1) a polyether polyol having an oxypropylene group with a number average molecular weight of 400 or more and 10000 or less,

A/B is 0.10 to 2.50 inclusive,

the average number of isocyanate functional groups is 2.6 or more and 10.0 or less.

3. The polyisocyanate composition according to claim 1, wherein the polyisocyanate is a polyisocyanate obtained from (A) at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates and (B2) a polyester-based polyol having a number average molecular weight of 250 or more and 4000 or less derived from 2-or more and 3-or less-membered alcohols and epsilon-caprolactone.

4. A coating composition comprising:

a polyol having a hydroxyl value of 5mgKOH/g or more and 200mgKOH/g or less; and

a polyisocyanate composition as claimed in any one of claims 1 to 3.

5. The coating composition of claim 4, which is used for coating of metal or plastic.

6. The coating composition according to claim 4 or 5, which is used as a top clear coating for building structures, automobile bodies, automobile metal parts, automobile plastic parts, metal parts for information home appliances, or plastic parts for information home appliances.

7. A coating film obtained by curing the coating composition according to any one of claims 4 to 6.