JP2019011402A - Modified organic polyisocyanate composition, and two-liquid-type coating composition using the same - Google Patents

Abstract

To provide a modified organic polyisocyanate composition having improved appearance stability with time after dilution by an organic solvent.SOLUTION: A modified organic polyisocyanate composition contains: at least one kind selected from the group consisting of a modified organic polyisocyanate composition containing an allophanate group (A1) and a modified organic polyisocyanate composition containing an urethane group (A2); and a compound having a specific phosphite structure (B).SELECTED DRAWING: None

Description

  The present invention relates to a modified organic polyisocyanate composition capable of improving the appearance stability when diluted with an organic solvent.

  Modified organic polyisocyanates obtained by modifying organic polyisocyanates are useful in the field of polyurethane plastics and are used in various fields. For example, it is used with polyols in the production of foams, fibers, films, elastomers and paints. In its use, the modified organic polyisocyanate is often diluted with an organic solvent. However, when the modified organic polyisocyanate is diluted with an organic solvent, it tends to discolor during storage. This property is particularly noticeable when the modified organic polyisocyanate must be stored at relatively high temperatures.

  It has already been proposed to add various stabilizers to the modified organic polyisocyanate in order to reduce the tendency to discolor the modified organic polyisocyanate. Known stabilizers include sterically hindered phenols, dialkyldiphenylamines, phenothiazines, phosphites, and mixtures of representatives of these compounds (Patent Documents 1 and 2).

  Among them, triphenyl phosphite (TPP) is effective for preventing discoloration at high temperatures (Patent Document 3). However, TPP has a drawback that it causes poor appearance when diluted and stored in an organic solvent. Therefore, there has been a demand for a stabilizer and a production method that overcome this problem.

US Pat. No. 3,715,381 Japanese Unexamined Patent Publication No. 1994-92925 Japanese Patent Publication No. 45-33438

  The present invention has been made in view of the background art described above, and an object thereof is to provide a modified organic polyisocyanate composition having improved appearance stability over time after dilution with an organic solvent.

  As a result of repeated studies, the present inventors have found that the above problems can be solved by a modified organic polyisocyanate containing a specific stabilizer, and have reached the present invention.

  That is, the present invention includes the following embodiments [1] to [5].

  [1] At least one selected from the group consisting of a modified organic polyisocyanate composition (A1) containing an allophanate group and a modified organic polyisocyanate composition (A2) containing a urethane group, and a phosphite represented by Formula 1 A modified organic polyisocyanate composition comprising a compound (B) having a structure.

* R _{1 to} R ₃ each independently represents an alkyl group or a phenyl group having an alkyl group on a benzene ring, and at least one of R _{1 to} R ₃ has a molecular weight of 78 or more.

[2] Compound (B) having a phosphite structure is tris (2,4-di-tert-butylphenyl) phosphite, 3,9-bis (2,6-di-tert-butyl-4-methylphenoxy). ) -2,4,8,10-tetraoxa-3,9-diphosphaspiro [5.5] undecane, 3,9-bis (octadecyloxy) -2,4,8,10-tetraoxa-3,9-diphosphaspiro [ 5.5] undecane, 2,2-methylenebis (4,6-di-tert-butylphenyl) 2-ethylhexyl phosphite, tris (nonylphenyl) phosphite, tetra-C _12-15 -alkyl (propane-2, 2-diylbis (4,1-phenylene)) bis (phosphite), 2-ethylhexyl diphenyl phosphite, isodecyl diphenyl phosphite Fight, selected from tri isodecyl phosphite, characterized in that at least one, modified organic polyisocyanate composition according to the above [1].

  [3] At least one selected from the group consisting of a modified organic polyisocyanate composition (A1) containing an allophanate group and a modified organic polyisocyanate composition (A2) containing a urethane group is a modified product of hexamethylene diisocyanate. The modified organic polyisocyanate composition according to [1] or [2], which is characterized in that it is present.

  [4] A two-component coating composition comprising the modified organic polyisocyanate composition according to any one of [1] to [3] above and a polyol.

  [5] A coating film obtained from the two-component coating composition according to [4].

  According to the modified organic polyisocyanate composition of the present invention, after diluting the organic solvent, the appearance after storage at a high temperature is greatly improved, and can be advantageously used for the subsequent production of polyurethane.

  Hereinafter, the present invention will be described in detail.

  The modified organic polyisocyanate composition in the present invention is at least one selected from the group consisting of a modified organic polyisocyanate composition (A1) containing an allophanate group and a modified organic polyisocyanate composition (A2) containing a urethane group. And a modified organic polyisocyanate composition comprising a compound (B) having a phosphite structure of the following formula 1.

* R _{1 to} R ₃ each independently represents an alkyl group or a phenyl group having an alkyl group on a benzene ring, and at least one of R _{1 to} R ₃ has a molecular weight of 78 or more.

  The modified organic polyisocyanate composition in the present invention can be suitably obtained by allophanatization or urethanization of an organic diisocyanate monomer and a hydroxyl group-containing compound in the presence of an allophanatization catalyst or a urethanization catalyst.

  Although it does not specifically limit as an organic diisocyanate monomer, For example, aliphatic diisocyanate, alicyclic diisocyanate, aromatic diisocyanate, araliphatic diisocyanate, etc. are mentioned.

<Aliphatic diisocyanate>
Specific examples of the aliphatic diisocyanate include hexamethylene diisocyanate, tetramethylene diisocyanate, 2-methyl-pentane-1,5-diisocyanate, 3-methyl-pentane-1,5-diisocyanate, lysine diisocyanate, trioxyethylene diisocyanate and the like. And mixtures thereof can also be used.

<Alicyclic diisocyanate>
Specific examples of the alicyclic diisocyanate include isophorone diisocyanate, cyclohexane diisocyanate, hydrogenated diphenylmethane diisocyanate, norbornane diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated xylene diisocyanate, hydrogenated tetramethylxylene diisocyanate, and the like. A mixture of these can also be used.

<Aromatic diisocyanate>
Specific examples of the aromatic diisocyanate include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate, 2,4′-diphenylmethane diisocyanate, 2,2′-diphenylmethane diisocyanate, 4,4′-diphenyl ether diisocyanate, 2-nitrodiphenyl-4,4′-diisocyanate, 2,2′-diphenylpropane-4,4′-diisocyanate, 3,3′-dimethyldiphenylmethane-4,4′-diisocyanate, 4,4′-diphenylpropane diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, naphthylene-1,4-diisocyanate, naphthylene-1,5-diisocyanate, 3,3′-dimethoxydiphenyl 4,4'-diisocyanate and the like can be mentioned, may also be used a mixture thereof.

<Aromatic aliphatic diisocyanate>
Specific examples of the aromatic aliphatic diisocyanate include 1,3- or 1,4-xylylene diisocyanate, 1,3- or 1,4-bis (1-isocyanato-1-methylethyl) benzene, ω, ω ′. -Diisocyanato-1, 4-diethylbenzene etc. can be mentioned, These mixtures can also be used.

  Although it does not specifically limit as a hydroxyl-containing compound, The compound which contains one or more hydroxyl groups in 1 molecule can be mentioned. Examples of such a hydroxyl group-containing compound include methanol, ethanol, propanol, n-butanol, isobutanol, n-pentanol, 2-pentanol, n-hexanol, 2-hexanol, n-heptanol, n-octanol, 2-ethyl-1-hexanol, 3,3,5-trimethyl-1-hexanol, n-tridecanol, 2-tridecanol, 2-octyldodecanol, pentadecanol, palmityl alcohol, stearyl alcohol, cyclopentanol, cyclo Examples thereof include monoalcohols such as hexanol, methylcyclohexanol and trimethylcyclohexanol, and C2 to C18 alkanediols.

  As a catalyst, it can select from a well-known catalyst suitably according to reaction to implement, and it is preferable to use an allophanatization catalyst or a urethanization catalyst in this invention.

  As the allophanatization catalyst, a basic catalyst such as a carboxylic acid metal salt can be used, for example, a zinc salt of a carboxylic acid such as acetic acid, propionic acid, undecyl acid, capric acid, octylic acid, myristic acid, tin salt, A zirconium salt etc. can be mentioned.

  As the urethanization catalyst, basic catalysts such as carboxylic acid metal salts can be used. For example, tin salts of carboxylic acids such as acetic acid, propionic acid, undecyl acid, capric acid, octylic acid, myristic acid, bismuth salts, etc. Can be mentioned.

  The modified organic polyisocyanate composition in the present invention contains a phosphite compound (B).

  The phosphite compound (B) in the present invention is a compound represented by the above formula 1, and among phosphite antioxidants available on the market as antioxidants, for example, tris (2,4-di-tert. -Butylphenyl) phosphite, 3,9-bis (2,6-di-tert-butyl-4-methylphenoxy) -2,4,8,10-tetraoxa-3,9-diphosphaspiro [5.5] undecane Examples thereof include compounds obtained from BASF under the trade name IRGAFOS, and compounds having a phosphite structure available from ADEKA under the trade name ADK STAB.

R _{1 to} R _{3 in} Formula 1 each independently represents an alkyl group or a phenyl group having an alkyl group on the benzene ring, and the molecular weight of at least one of R _{1 to} R ₃ is 78 or more. In order to enhance the appearance defect suppressing effect, at least one molecular weight of R _{1 to} R ₃ is preferably 113 or more, and more preferably 190 or more.

  The content of the compound (B) having a phosphite structure is 0.01 with respect to the modified organic polyisocyanate composition (A1) containing an allophanate group or the modified organic polyisocyanate composition (A2) containing a urethane group. It is preferable to contain-1 mass%, and it is still more preferable to contain 0.05-0.5 mass%.

  Next, a specific method for producing the modified organic polyisocyanate composition of the present invention will be described.

  In the first step, an organic diisocyanate monomer and a hydroxyl group-containing compound are charged in an amount in which an isocyanate group becomes excessive with respect to a hydroxyl group, and urethanized and allophanate at 50 to 150 ° C. in the presence or absence of an organic solvent. An isocyanate group-terminated prepolymer I is produced by performing at least one reaction among the conversion reactions. As a measure of the reaction here, the completion is judged by the isocyanate group content and the refractive index increase value by the neutralization titration method.

  In the second step, the reaction is stopped by adding a reaction terminator to the isocyanate group-terminated prepolymer I.

  In these 1st process-2nd process, reaction is advanced under nitrogen gas or a dry air stream.

  In the third step, the isocyanate group-terminated prepolymer obtained in the second step is removed by thin film distillation or solvent extraction until the content of free organic diisocyanate monomer is less than 1% by mass to obtain a modified organic polyisocyanate. .

  Here, the “amount of isocyanate group excess” in the first step is preferably such that the molar ratio of isocyanate group to hydroxyl group is 5 to 75 (R = isocyanate group / hydroxyl group). It is more preferable to prepare so that it may become 5-50. When the amount is less than the lower limit, the amount of a polyisocyanate composition having a molecular weight higher than that of the target product is increased, which may increase the viscosity. If the upper limit is exceeded, the viscosity increases and the product yield decreases, which may lead to a decrease in productivity.

  Examples of the organic diisocyanate monomer used in the first step include various diisocyanates described above.

  Examples of the hydroxyl group-containing compound used in the first step include the various hydroxyl group-containing compounds described above.

  In the first step, a catalyst can be used, and examples of the catalyst used for the reaction include the above-described catalysts.

  The reaction in the first step can also be performed in various organic solvents that do not affect the reaction. Examples of the organic solvent include aliphatic hydrocarbons, alicyclic hydrocarbons, ketones, esters, Examples include glycol ether esters, ethers, halogenated hydrocarbons, and polar aprotic solvents.

  Examples of the aliphatic hydrocarbons include n-hexane and octane.

  Examples of the alicyclic hydrocarbons include cyclohexane and methylcyclohexane.

  Examples of ketones include acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone.

  Examples of the esters include methyl acetate, ethyl acetate, butyl acetate, and isobutyl acetate.

  Examples of glycol ether esters include ethylene glycol ethyl ether acetate, propylene glycol methyl ether acetate, 3-methyl-3-methoxybutyl acetate, ethyl-3-ethoxypropionate, and the like.

  Examples of ethers include diethyl ether, tetrahydrofuran, dioxane and the like.

  Examples of halogenated hydrocarbons include methyl chloride, methylene chloride, chloroform, carbon tetrachloride, methyl bromide, methylene iodide, dichloroethane, and the like.

  Examples of the polar aprotic solvent include N-methylpyrrolidone, dimethylformamide, dimethylacetamide, dimethyl sulfoxide, hexamethylphosphonilamide and the like.

  These solvents can be used alone or in combination of two or more.

  The organic solvent used in the reaction is removed simultaneously with the removal of free organic diisocyanate in the third step.

  The reaction terminator in the second step has a function of deactivating the activity of the catalyst. Specifically, the organic acid has an inorganic acid such as phosphoric acid or hydrochloric acid, a sulfonic acid group, a sulfamic acid group, or the like. In addition, known compounds such as esters and acyl halides are used. These reaction terminators can be used alone or in combination of two or more. In addition, the addition time is preferably a rapid addition after completion of the reaction.

  Moreover, although the addition amount of reaction terminator changes with kinds of reaction terminator and the catalyst used, it is preferable that it becomes 0.5-10 equivalent of a catalyst, and 0.8-5.0 equivalent is especially preferable. When there are few reaction terminators, the storage stability of the obtained polyisocyanate composition tends to be lowered, and when it is too much, the modified polyisocyanate may be colored.

  The compound (B) having a phosphite structure may be added at any timing, but is preferably added from the beginning of the second step to the end of the third step. More preferably, before the start of the third step.

  In the purification step of the third step, the free unreacted organic diisocyanate monomer present in the reaction mixture is removed, for example, by thin film distillation at 120 to 150 ° C. under a high vacuum of 10 to 100 Pa or with an organic solvent. The residual content is adjusted to 1.0% by mass or less by an extraction method. In addition, when the residual content rate of an organic diisocyanate monomer exceeds an upper limit, there exists a possibility of causing the generation | occurrence | production of an odor and the fall of storage stability.

  The modified organic polyisocyanate obtained by purification can be converted to a blocked isocyanate using a known blocking agent for the purpose of extending the pot life or making the coating composition one component. As a result, the blocked polyisocyanate is inactive at room temperature, but when heated, the blocking agent dissociates, and the isocyanate group is activated again, thereby causing a potential function to react with the active hydrogen group. Can be added.

  The blocking agent that can be used in the present invention is a compound having one active hydrogen group in the molecule, and examples thereof include alcohols, alkylphenols, phenols, active methylenes, mercaptans, acid amides, and acid imides. , Imidazole, urea, oxime, amine, imide, and pyrazole compounds.

  Moreover, the modified organic polyisocyanate obtained by a series of reactions can obtain the two-component coating composition of the present invention by blending a polyol.

  Here, the polyol used in the two-component coating composition of the present invention is not particularly limited, but is a compound containing an active hydrogen group as a reactive group with an isocyanate group, such as a polyester polyol, Suitable examples include polyether polyols, polycarbonate polyols, polyolefin polyols, acrylic polyols, silicone polyols, castor oil-based polyols, fluorine-based polyols, transesterification products of two or more polyols, and hydroxyl-terminated prepolymers that have undergone a urethanization reaction with polyisocyanates. These can be used as one kind or a mixture of two or more kinds.

<Polyester polyol>
Specific examples of the polyester polyol include, for example, phthalic acid, isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, succinic acid, tartaric acid, oxalic acid, malonic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, glutaconic acid, azelaic acid. , Sebacic acid, 1,4-cyclohexyl dicarboxylic acid, α-hydromuconic acid, β-hydromuconic acid, α-butyl-α-ethylglutaric acid, α, β-diethylsuccinic acid, maleic acid, fumaric acid, etc. One or more of acids or anhydrides thereof, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol 1,9-nonanediol, 3-methyl-1,5-pentanediol, 3,3-dimethylolheptane, diethylene glycol, dipropylene glycol, neopentyl glycol, cyclohexane-1,4-diol, cyclohexane-1,4- Low molecular weight polyols having a molecular weight of 500 or less such as dimethanol, dimer acid diol, bisphenol A ethylene oxide and propylene oxide adducts, bis (β-hydroxyethyl) benzene, xylylene glycol, glycerin, trimethylolpropane, pentaerythritol, etc. Examples thereof include those obtained from a condensation polymerization reaction with one or more kinds. Also, lactone polyester polyols obtained from ring-opening polymerization of cyclic ester monomers such as ε-caprolactone, alkyl-substituted ε-caprolactone, δ-valerolactone, and alkyl-substituted δ-valerolactone. Furthermore, a polyester-amide polyol obtained by replacing a part of the low molecular polyol with a low molecular polyamine such as hexamethylene diamine, isophorone diamine, monoethanolamine, or a low molecular amino alcohol can also be used.

<Polyether polyol>
Specific examples of the polyether polyol include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1, 5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 3-methyl-1,5-pentanediol, 3,3-dimethylolheptane, diethylene glycol, dipropylene glycol , Neopentyl glycol, cyclohexane-1,4-diol, cyclohexane-1,4-dimethanol, dimer acid diol, bisphenol A, bis (β-hydroxyethyl) benzene, xylylene glycol, glycerin, trimethylolpropane, pentaerythritol Small molecules such as Initiates compounds having 2 or more, preferably 2-3 active hydrogen groups such as diols or low molecular weight polyamines such as ethylenediamine, propylenediamine, toluenediamine, metaphenylenediamine, diphenylmethanediamine, xylylenediamine, etc. As an agent, polyether polyols obtained by addition polymerization of alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, etc., or alkyl glycidyl ethers such as methyl glycidyl ether, aryl glycidyl ethers such as phenyl glycidyl ether And polyether polyols obtained by ring-opening polymerization of cyclic ether monomers such as tetrahydrofuran.

<Polycarbonate polyol>
Specific examples of the polycarbonate polyol include, for example, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5 -Pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 3-methyl-1,5-pentanediol, 3,3-dimethylolheptane, diethylene glycol, dipropylene glycol, Neopentyl glycol, cyclohexane-1,4-diol, cyclohexane-1,4-dimethanol, dimer acid diol, bisphenol A ethylene oxide or propylene oxide adduct, bis (β-hydroxyethyl) benzene, xylylene glycol, glycerin The One or more kinds of low molecular polyols such as methylolpropane and pentaerythritol, dialkyl carbonates such as dimethyl carbonate and diethyl carbonate, alkylene carbonates such as ethylene carbonate and propylene carbonate, diphenyl carbonate, dinaphthyl carbonate, dianthryl carbonate, di Examples thereof include those obtained from dealcoholization reaction and dephenol reaction with diaryl carbonates such as phenanthryl carbonate, diindanyl carbonate, and tetrahydronaphthyl carbonate.

  Moreover, the polyol obtained by transesterification of polycarbonate polyol, polyester polyol, and low molecular polyol can also be used suitably.

<Polyolefin polyol>
Specific examples of the polyolefin polyol include polybutadiene having two or more hydroxyl groups, hydrogenated polybutadiene, polyisoprene, hydrogenated polyisoprene, and the like.

<Acrylic polyol>
Examples of the acrylic polyol include acrylic acid ester and / or methacrylic acid ester (hereinafter referred to as (meth) acrylic acid ester), acrylic acid hydroxy compound having at least one hydroxyl group in the molecule and / or methacrylic acid which can be a reaction point. An acid hydroxy compound (hereinafter referred to as a (meth) acrylic acid hydroxy compound) and a polymerization initiator may be used in which an acrylic monomer is copolymerized using thermal energy, light energy such as ultraviolet rays or electron beams, and the like. .

<(Meth) acrylic acid ester>
Specific examples of (meth) acrylic acid esters include alkyl esters having 1 to 20 carbon atoms. Specific examples of such (meth) acrylate esters include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, and pentyl (meth) acrylate. (Meth) such as hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate Acrylic acid alkyl ester, cyclohexyl (meth) acrylate and other (meth) acrylic acid esters with alicyclic alcohols, (meth) acrylic acid phenyl and (meth) acrylic acid aryl esters such as benzyl (meth) acrylate Can be mentioned. Such (meth) acrylic acid esters can be used singly or in combination of two or more.

<(Meth) acrylic acid hydroxy compound>
Specific examples of the (meth) acrylic acid hydroxy compound have at least one hydroxyl group in the molecule that can be a reaction point with polyisocyanate. Specifically, for example, 2-hydroxyethyl acrylate, 2-hydroxy Acrylic hydroxy compounds such as hydroxypropyl acrylate, 4-hydroxybutyl acrylate, 3-hydroxy-2,2-dimethylpropyl acrylate, pentaerythritol triacrylate and the like can be mentioned. Moreover, methacrylic acid hydroxy compounds, such as 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 4-hydroxybutyl methacrylate, 3-hydroxy-2,2-dimethylpropyl methacrylate, pentaerythritol trimethacrylate, etc. are mentioned. As these (meth) acrylic acid hydroxy compounds, one or a combination of two or more may be mentioned.

<Silicone polyol>
Specific examples of the silicone polyol include, for example, a vinyl group-containing silicone compound obtained by polymerizing γ-methacryloxypropyltrimethoxysilane and the like, α, ω-dihydroxypolydimethylsiloxane having at least one terminal hydroxyl group in the molecule, α , Ω-dihydroxypolydiphenylsiloxane, and the like.

<Castor oil-based polyol>
Specific examples of the castor oil-based polyol include linear or branched polyester polyols obtained by the reaction of castor oil fatty acid and polyol. Dehydrated castor oil, partially dehydrated castor oil partially dehydrated, and hydrogenated castor oil added with hydrogen can also be used.

<Fluorine-based polyol>
Specific examples of the fluorine-based polyol include linear or branched polyols obtained by a copolymerization reaction using, for example, a fluorine-containing monomer and a monomer having a hydroxy group as essential components. Here, the fluorine-containing monomer is preferably a fluoroolefin, for example, tetrafluoroethylene, chlorotrifluoroethylene, trichlorofluoroethylene, hexafluoropropylene, vinylidene fluoride, vinyl fluoride, trifluoromethyl trifluoroethylene. Etc. Examples of the monomer having a hydroxyl group include hydroxyalkyl vinyl ethers such as hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether and cyclohexanediol monovinyl ether, hydroxyalkyl allyl ethers such as 2-hydroxyethyl allyl ether, and hydroxyalkyl vinyl crotonates. And monomers having a hydroxyl group, such as a hydroxyl group-containing vinyl carboxylate or allyl ester.

  The polyol preferably has an active hydrogen group number (average functional group number) in one molecule of 1.9 to 6.0. When the number of active hydrogen groups is less than the lower limit, the physical properties of the coating film may be reduced. Moreover, when exceeding an upper limit, there exists a possibility that adhesiveness may fall.

  Moreover, it is preferable that the number average molecular weight of a polyol exists in the range of 500-50000. If it is less than the lower limit, the adhesion may be reduced, and if it exceeds the upper limit, the solubility in a low-polar organic solvent may be lowered or the adhesion may be lowered.

  Further, the blending ratio of the polyisocyanate composition of the two-component coating composition of the present invention and the polyol is not particularly limited, but the molar ratio of the isocyanate group in the isocyanate composition to the hydroxyl group in the polyol is It is preferable that R = isocyanate group / hydroxyl group to be 0.5 to 2.5. If it is less than the lower limit, the hydroxyl group becomes excessive, which may cause a decrease in adhesion. Moreover, there exists a possibility that a crosslinking density may fall and durability and the mechanical strength of a coating film may fall. When the upper limit is exceeded, the isocyanate group becomes excessive and reacts with moisture in the air, which may cause swelling of the coating film and a decrease in adhesion.

  Moreover, as an organic solvent used as a diluting solvent, ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone, esters such as ethyl acetate, butyl acetate and cellosolve, alcohols such as butanol and isopropyl alcohol, toluene, xylene, From the group consisting of hydrocarbons such as cyclohexane, mineral spirits, naphtha and the like, it can be appropriately selected and used according to the purpose and application. These solvents may be used alone or in combination of two or more.

  Moreover, the two-component coating composition of the present invention can use a known urethanization catalyst as appropriate in consideration of pot life, curing conditions, working conditions, and the like. Specifically, organic metal compounds such as dibutyltin diacetate, dibutyltin dilaurate and dioctyltin dilaurate, organic amines such as triethylenediamine and triethylamine, and salts thereof are selected and used. These catalysts can be used alone or in combination of two or more.

  Further, the curing conditions of the two-component coating composition of the present invention are not particularly limited, but the curing temperature is -5 to 120 ° C, the humidity is 10 to 95% RH, and the curing time is 0.5 to 0.5. Preferably it is 168 hours.

  The two-component coating composition obtained by the present invention is applied onto the surface of an adherend by a known method such as spraying, brushing, dipping, or coater to form a coating film.

  Here, the adherend is not particularly limited, and is stainless steel, phosphate-treated steel, zinc steel, iron, copper, aluminum, brass, glass, slate, acrylic resin, polycarbonate resin, polyethylene terephthalate resin, polyethylene naphthalate. Resin, polybutylene phthalate resin, polystyrene resin, AS resin, ABS resin, polycarbonate-ABS resin, 6-nylon resin, 6,6-nylon resin, MXD6 nylon resin, polyvinyl chloride resin, polyvinyl alcohol resin, polyurethane resin, phenol Resin, melamine resin, polyacetal resin, chlorinated polyolefin resin, polyolefin resin, polyamide resin, polyether ether ketone resin, polyphenylene sulfide resin, NBR resin, chloroprene resin, SBR resin, SE An adherend formed of a material such as S resin, an olefin resin such as polyethylene or polypropylene subjected to corona discharge treatment or other surface treatment, or an intermediate layer such as a primer layer was formed on the adherend surface. An adherend can be used.

  Since the film thickness of the coating film formed on the adherend surface layer is excellent in recoatability and durability, a film thickness of at least 10 μm may be formed on the adherend. When the film thickness is less than 10 μm, the durability is lowered, and there is a possibility that the coating film is torn by impact.

  EXAMPLES Hereinafter, although this invention is demonstrated further in detail based on an Example, this invention is not limited to a following example. In addition, the% description in an Example is a mass reference | standard unless there is particular notice.

<Synthesis of polyisocyanate composition>
<Example 1>
Into a 1-liter four-necked flask equipped with a stirrer, a thermometer, a cooling pipe, and a nitrogen gas introduction pipe, 910 g of hexamethylene diisocyanate (manufactured by Tosoh Corporation, NCO content: 49.9% by mass, hereinafter referred to as HDI), and 90 g of n-octanol (manufactured by Sanyo Kasei Kogyo Co., Ltd.) was charged and the temperature was raised to 60 ° C. while stirring. Zirconyl octylate (manufactured by Daiichi Rare Element Chemical Co., Ltd.) as an allophanate catalyst was added to this reaction solution. 0.1 g is added and reacted at 110 ° C. until a predetermined refractive index is reached. Then, 0.11 g of acidic phosphate ester (JP-508, manufactured by Johoku Chemical Industry Co., Ltd.) as a reaction terminator is added. A stop reaction was carried out at 1 ° C. for 1 hour. Here, 0.3 g of tris (2,4-di-tert-butylphenyl) phosphite (manufactured by BASF, IRGAFOS 168) was added, and the mixture was stirred and mixed at 60 ° C. for 1 hour. Thereafter, excess HDI was removed from the reaction product by thin film distillation (conditions: 140 ° C., 0.04 kPa) to obtain 430 g of modified organic polyisocyanate P-1.

<Example 2>
Synthesis was performed under the conditions shown in Table 1, and each modified polyisocyanate P-2 was obtained in the same procedure as in Example 1.

<Example 3>
In a 1 liter four-necked flask equipped with a stirrer, thermometer, condenser, and nitrogen gas inlet tube, 592 g of HDI, 158 g of trimethylolpropane (Mitsubishi Gas Chemical Co., Ltd.), and 250 g of ethyl acetate (manufactured by Showa Denko KK) The mixture was heated to 60 ° C. with stirring, and reacted until a predetermined NCO content was reached. Thereafter, 0.3 g of tris (2,4-di-tert-butylphenyl) phosphite (manufactured by BASF, IRGAFOS 168) was added and mixed with stirring at 60 ° C. for 1 hour, and 1000 g of modified organic polyisocyanate P-3 was added. Obtained.

<Comparative Example 1>
Synthesis was performed under the conditions shown in Table 1, and each modified polyisocyanate P-4 was obtained in the same procedure as in Example 1.

<Comparative Example 2>
910 g of HDI and 90 g of n-octanol (manufactured by Sanyo Kasei Kogyo Co., Ltd.) were charged into a 1-liter four-necked flask equipped with a stirrer, a thermometer, a cooling pipe, and a nitrogen gas introduction pipe, and these were stirred at 60 ° C. After adding 0.1 g of zirconyl octylate (Daiichi Rare Element Chemical Co., Ltd.), which is an allophanatization catalyst, to this reaction solution, the reaction was carried out at 110 ° C. until a predetermined refractive index was reached. Then, 0.11 g of acidic phosphate ester (JP-508, manufactured by Johoku Chemical Industry Co., Ltd.) as a reaction terminator was added, and a termination reaction was performed at 60 ° C. for 1 hour. Thereafter, excess HDI was removed from the reaction product by thin-film distillation (conditions: 140 ° C., 0.04 kPa) to obtain 430 g of modified organic polyisocyanate P-5.

The raw materials used in Table 1 are as follows.
Acidic phosphate ester: di-2-ethylhexyl phosphate (JP-508, manufactured by Johoku Chemical Industry Co., Ltd.)
・ Catalyst-1: Zirconyl octylate (Daiichi Rare Element Chemical Co., Ltd.)
Antioxidant-1: Tris (2,4-di-tert-butylphenyl) phosphite (IRGAFOS 168, manufactured by BASF)
Antioxidant-2: 3,9-bis (2,6-di-tert-butyl-4-methylphenoxy) -2,4,8,10-tetraoxa-3,9-diphosphaspiro [5.5] undecane (ADK STAB PEP-36, manufactured by ADEKA)
Antioxidant-3: Triphenyl phosphite (Adeka Stub TPP, manufactured by ADEKA).

<Evaluation of the number of colors>
For the evaluation of the number of colors, the Hazen unit color number (platinum-cobalt scale) method described in JIS K0071-1 was used.

<Turbidity evaluation>
For the evaluation of turbidity, the method of kaolin turbidity (visual method) shown in JIS K 0101 was used.

<Solvent dilution stability>
<Initial value>
The obtained modified organic polyisocyanates P-1 to P-5 were diluted with methyl ethyl ketone (MEK) to a solid content of 20%, and the number of colors and turbidity were measured.
<50 ° C x 3 months later>
A modified organic polyisocyanate P-1 to P-5 diluted with MEK to a solid content of 20% was stored at 50 ° C. for 3 months, and its color number and turbidity were measured.

  In each example, good results were obtained. On the other hand, when P-4 as a comparative example was diluted with MEK, the number of colors after 3 months storage at 50 ° C. did not change greatly, but an increase in turbidity was observed. P-5 had a tendency for the number of colors of the sample to be high, and those diluted with MEK also showed a tendency for the number of colors to increase after storage at 50 ° C. for 3 months.

Claims (5)

At least one selected from the group consisting of a modified organic polyisocyanate composition (A1) containing an allophanate group and a modified organic polyisocyanate composition (A2) containing a urethane group, and a phosphite structure represented by Formula 1 A modified organic polyisocyanate composition comprising a compound (B).

(R _{1 to} R ₃ each independently represents an alkyl group or a phenyl group having an alkyl group on the benzene ring, and at least one of R _{1 to} R ₃ has a molecular weight of 78 or more.) Compound (B) having a phosphite structure is tris (2,4-di-tert-butylphenyl) phosphite, 3,9-bis (2,6-di-tert-butyl-4-methylphenoxy) -2. , 4,8,10-tetraoxa-3,9-diphosphaspiro [5.5] undecane, 3,9-bis (octadecyloxy) -2,4,8,10-tetraoxa-3,9-diphosphaspiro [5.5 ] Undecane, 2,2-methylenebis (4,6-di-tert-butylphenyl) 2-ethylhexyl phosphite, tris (nonylphenyl) phosphite, tetra-C _12-15 -alkyl (propane-2,2-diylbis) (4,1-phenylene)) bis (phosphite), 2-ethylhexyl diphenyl phosphite, isodecyl diphenyl phosphat DOO, selected from tri isodecyl phosphite, characterized in that at least one, modified organic polyisocyanate composition according to claim 1.   That at least one selected from the group consisting of a modified organic polyisocyanate composition (A1) containing an allophanate group and a modified organic polyisocyanate composition (A2) containing a urethane group is a modified product of hexamethylene diisocyanate. The modified organic polyisocyanate composition according to claim 1, wherein the composition is a modified organic polyisocyanate composition.   A two-component coating composition comprising the modified organic polyisocyanate composition according to any one of claims 1 to 3 and a polyol.   A coating film obtained from the two-component coating composition according to claim 4.