JP2007270046A - Carbodiimide compound, curing agent and curable resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a carbodiimide compound that is reduced in adverse effect on the environment and can be used suitably as a curing agent for various uses such as coating materials, and to provide a curable resin composition containing it. <P>SOLUTION: Provided is an oxazolidone ring-containing carbodiimide compound having a structure in which the oxazolidone ring is bonded to one terminal or both terminals of its carbodiimide unit. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a carbodiimide compound, a curing agent, and a curable resin composition.

Conventionally, curing agents have been widely used in various applications such as paints, adhesives, and coating agents. Among various applications, the isocyanate compound used as a curing agent for coatings has a highly reactive isocyanate group at its end, so that it can exist stably in the coating system as a curing agent. It was necessary to seal the terminal isocyanate group with a blocking agent such as oximes and alcohols (for example, see Non-Patent Document 1).

On the other hand, it has also been proposed to use a carbodiimide compound as a curing agent for coatings, but this compound also usually has an isocyanate group at the terminal. For this reason, what sealed the isocyanate group of the terminal with the blocking agent for the same reason as the case of an isocyanate compound is usually used.

However, since oximes and alcohols used as such blocking agents are volatilized as released products and released out of the system when the isocyanate group is regenerated by heating after coating, it is a recent environmental problem. We have a problem from the viewpoint of consideration.

As carbodiimide-based crosslinking agents that do not use oximes or alcohols as blocking agents, those having water-soluble or water-dispersible polycarbodiimide compounds whose terminal isocyanate groups are sealed with hydrophilic groups as the main component are disclosed. (See Patent Document 1).

However, like the above blocking agent, such a hydrophilic group is eliminated during heating but does not evaporate out of the system and remains in the coating film, thus acting as a plasticizer that lowers the water resistance of the coating film. Therefore, there is a concern about the deterioration of the coating film performance, such as the deterioration of the coating film properties.
“Characteristics and Functions of Paint”, page 98, right column to page 100, right column (Nippon Paint Co., Ltd., Nippon Paint Newspaper, published in 1998, first edition) Japanese Patent Laid-Open No. 10-316930

In view of the above-mentioned present situation, the present invention has an object to provide a carbodiimide compound that can be suitably used as a curing agent for various uses such as paints and the like, and a curable resin composition including the carbodiimide compound. It is what.

The present invention is an oxazolidone ring-containing carbodiimide compound having a structure in which an oxazolidone ring is bonded to one or both ends of a carbodiimide unit.
The present invention is also an oxazolidone ring-containing carbodiimide compound obtained by reacting a carbodiimide compound having an isocyanate group at a terminal with a compound having an epoxy group.

This invention is also a hardening | curing agent characterized by consisting of the above-mentioned oxazolidone ring containing carbodiimide compound.
The present invention is also a curable resin composition comprising the oxazolidone ring-containing carbodiimide compound described above.

The oxazolidone ring-containing carbodiimide compound of the present invention is a compound having a structure in which an oxazolidone ring is bonded to one end or both ends of a carbodiimide unit. For this reason, when this is used as a curing agent for paints, the amount of detachment of organic components derived from the curing agent can be suppressed during heat curing and after the formation of the cured coating film, which is excellent from the environmental viewpoint. . Further, when an epoxy resin skeleton is present in the obtained coating film, the anticorrosion property of the coating film can be improved. Furthermore, when the present invention is a compound having a carbodiimide unit and an epoxy group and is used as a curing agent for paints, it can be expected that various performances can be imparted to the coating film.

The oxazolidone ring-containing carbodiimide compound of the present invention is a compound having a structure in which an oxazolidone ring is bonded to one end or both ends of a carbodiimide unit. That is, one end or both ends of the carbodiimide unit is sealed with an oxazolidone ring, and when this compound is used as a curing agent for a coating, during the heat curing after coating and over time after forming a cured coating film, The amount of the organic component derived from the curing agent can be suppressed. In particular, when both ends of all carbodiimide units in the compound are sealed with oxazolidone rings, there is no organic component derived from this sealing site. Therefore, the oxazolidone ring-containing carbodiimide compound of the present invention is excellent from the viewpoint of consideration for environmental problems.

When the oxazolidone ring-containing carbodiimide compound is used as a curing agent for paints, the corrosion resistance of the coating film can be improved when an epoxy resin skeleton is present in the obtained coating film. Moreover, since it is a compound sealed with an oxazolidone ring, there is no deterioration in coating film properties such as water resistance as in a compound whose end is sealed with a hydrophilic group.

The oxazolidone ring-containing carbodiimide compound of the present invention is a compound having a structure in which an oxazolidone ring is bonded to one end or both ends of a carbodiimide unit. The oxazolidone ring-containing carbodiimide compound of the present invention is not necessarily a single compound, and may be a mixture of various compounds.

The carbodiimide unit is a unit represented by — (— N═C═N—R—) _n —. The oxazolidone ring-containing carbodiimide compound comprises a carbon atom of a hydrocarbon group (R) located at one or both ends of the carbodiimide unit [— (— N═C═N—R—) _n —], and an oxazolidone ring. It has a structure in which the constituent nitrogen atoms are bonded. The structure in which the oxazolidone ring is bonded to one end of the carbodiimide unit is represented by the following general formula (1), and the structure bonded to both ends is represented by the following general formula (2).

When the present invention is a compound having a structure in which an oxazolidone ring is bonded to one end of a carbodiimide unit (structure represented by the above general formula (1)), examples of the other end of the carbodiimide unit include oximes and alcohols. Examples thereof include those sealed with a conventionally known isocyanate group blocking agent. Further, the compound having a structure represented by a structure in which an oxazolidone ring is bonded to one end may be a branched type, a graft type, or the like.

N is the average degree of polymerization of the carbodiimide unit, and is preferably 2-20. If it exceeds 20, the reaction efficiency of the synthesis of the carbodiimide compound may be reduced. More preferably, it is 2-10. R represents a hydrocarbon group. The hydrocarbon group may be either saturated or unsaturated, and may contain a nitrogen atom and / or an oxygen atom. The hydrocarbon group is preferably a group having 6 to 40 carbon atoms. If it is less than 6, there are no industrial raw materials and production is difficult, and if it exceeds 40, the curability may be lowered. More preferably, it is 6-20.

Examples of the hydrocarbon group having 6 to 40 carbon atoms include alkylene groups having 6 to 40 carbon atoms such as octylene group, nonylene group, decylene group, undecylene group, dodecylene group, tridecylene group, tetradecylene group, etc .; phenylene group, nonyl A phenylene group etc. can be mentioned. Moreover, the group represented by the following chemical formula can also be mentioned.

The oxazolidone ring-containing carbodiimide compound of the present invention is not particularly limited as long as it is a compound having the above structure, but is preferably a compound having a structure in which an oxazolidone ring is bonded to both ends of a carbodiimide unit, and all carbodiimides in the compound Those having an oxazolidone ring bonded to both ends of the unit are particularly preferred. In this case, it is preferable from the viewpoints of coating properties such as environmental aspects, corrosion resistance, and water resistance.

The oxazolidone ring-containing carbodiimide compound having a structure in which an oxazolidone ring is bonded to both ends of the carbodiimide unit is not particularly limited, but compounds represented by the following general formulas (3) and (4) are preferable. Thereby, the effect of this invention can be acquired favorably.

In the general formula (3), X represents a structure obtained by removing one epoxy group from a compound having an epoxy group. R represents a hydrocarbon group having 6 to 40 carbon atoms which may be saturated or unsaturated and may contain a nitrogen atom, an oxygen atom and / or a sulfur atom. n is an average degree of polymerization and represents 2-20. R and n are the same as R and n described above. X and R may be the same or different.

In X in the general formula (3), the compound having an epoxy group is not particularly limited as long as it is a compound having at least one epoxy group, but is preferably a compound having at least two epoxy groups. In the present specification, the “compound having an epoxy group” includes a polymer.

Examples of the compound having one epoxy group include butyl glycidyl ether and glycidyl phenyl ether.
Examples of the compound having at least two epoxy groups include polyglycidyl ethers of polyhydric alcohols. Among the polyhydric alcohols, dihydric alcohols include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,5-hexanediol, diethylene glycol, triethylene glycol. Tetraethylene glycol, pentaethylene glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, bisphenol A alkylene oxide adduct, bisphenol S alkylene oxide adduct, 1,2-propanediol, neopentyl glycol, 1 , 2-butanediol, 1,3-butanediol, 1,2-pentanediol, 2,3-pentanediol, 1,4-pentanediol, 1,4-hexanediol, 2,5-hexanediol, 3- Methyl-1 5-pentanediol, 1,2-dodecanediol, 1,2-octadecanediol, polyethylene glycol, and polypropylene glycol. Furthermore, examples of the trihydric or higher alcohol include trimethylolpropane, glycerin, pentaerythritol, and sorbitol. When the polyhydric alcohol is trivalent or more, it is sufficient that at least two hydroxyl groups are glycidyl etherified, and the hydroxyl groups may remain. Among the polyglycidyl ethers of the polyhydric alcohol, polyglycerol polyglycidyl ether, polyethylene glycol diglycidyl ether, and polypropylene glycol diglycidyl ether are preferable.

The compound having at least two epoxy groups may be an epoxy resin. Examples of such an epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, novolac type epoxy resin, and halogenated bisphenol A. Type epoxy resin, halogenated novolac type epoxy resin, isocyanuric acid epoxy resin, terephthalic acid epoxy resin and the like. The compound having at least two epoxy groups may be an acrylic resin having an epoxy group. In this case, glycidyl (meth) acrylate, β-methylglycidyl (meth) acrylate and 3,4-epoxycyclohexa The acrylic resin having an epoxy group is obtained by homopolymerizing or copolymerizing an acrylic monomer having an epoxy group such as nyl (meth) acrylate by a method well known to those skilled in the art. The acrylic resin having an epoxy group is useful because its epoxy equivalent can be easily adjusted. X may be the same or different.

When the compound having at least two epoxy groups is an epoxy resin or an acrylic resin, the epoxy equivalent indicating the molecular weight per epoxy group is preferably 130 to 15000. Those less than 130 are difficult to obtain, and if it exceeds 15,000, the reaction rate with the isocyanate group may decrease.

In the case of the compound of the general formula (4), a carboxyl group can react with both the epoxy group and the carbodiimide unit bonded to Y. Therefore, when this compound is used as a curing agent for a coating, It is possible to adjust the crosslinked structure and the like, and it can be expected that a coating film having various characteristics can be obtained.

In the said General formula (4), Y represents the structure remove | excluding all the epoxy groups from the compound which has two epoxy groups. R represents a hydrocarbon group having 6 to 40 carbon atoms which may be saturated or unsaturated and may contain a nitrogen atom and / or an oxygen atom. n is an average degree of polymerization and represents 2-20. m is the average number of repeating units, and represents 0-25. R and n are the same as R and n described above. Y, R and n may be the same or different. In Y, the compound having two epoxy groups may be the same as the compound having two epoxy groups among those exemplified as the compound having at least two epoxy groups. If m exceeds 25, the reaction efficiency of the synthesis of the carbodiimide compound may be reduced. The m is more preferably 0-10.

Although the manufacturing method of the oxazolidone ring containing carbodiimide compound of this invention is not specifically limited, It is preferable to manufacture by making the carbodiimide compound which has an isocyanate group at the terminal, and the compound which has an epoxy group react. Thereby, an oxazolidone ring can be formed in the terminal isocyanate group. Examples of the carbodiimide compound having an isocyanate group at the terminal include those having an isocyanate group at one or both terminals.

Among the carbodiimide compounds having an isocyanate group at the terminal, the method for producing a carbodiimide compound having an isocyanate group at both terminals is well known to those skilled in the art and can be produced by a condensation reaction involving decarbonization of organic diisocyanate. it can.
The organic diisocyanate is not particularly limited, and examples thereof include aromatic diisocyanates, aliphatic diisocyanates, alicyclic diisocyanates, aralkyl diisocyanates, and mixtures thereof. For example, 4,4′-diphenylmethane diisocyanate (MDI), 2,6-tolylene diisocyanate (2,6-TDI), 2,4-tolylene diisocyanate (2,4-TDI), naphthalene diisocyanate (NDI), 1-methoxybenzene-2,4-diisocyanate (MBDI), Xylylene diisocyanate (XDI), metaxylene diisocyanate (MXDI), 1,6-hexamethylene diisocyanate (HDI), 2,2,4-trimethylhexamethylene diisocyanate (TMHDI), 1,12-diisocyanate Can (DDI), hydrogenated xylylene diisocyanate (HXDI), norbornane diisocyanate (NBDI), isophorone diisocyanate (IPDI), 2,4-bis (8-isocyanatooctyl) -1,3-dioctylcyclobutane (OCDI), 4 , 4'-dicyclohexylmethane diisocyanate (HMDI), xylylene diisocyanate (XDI), tetramethylxylylene diisocyanate (TMXDI), diphenyl sulfide-4,4'-diisocyanate, diphenylsulfone-4,4'-diisocyanate, diphenyl ether-4 4,4'-diisocyanate, diphenyl ketone-4,4'-diisocyanate, and the like.

In the above condensation reaction, 1-phenyl-2-phospholene-1-oxide, 3-methyl-2-phospholene-1-oxide, 1-methyl-1-phospha-2-cyclopentene-1 is usually used as a carbodiimidization catalyst. -Oxide, 1-methyl-1-phospha-3-cyclopentene-1-oxide, 1-ethyl-2-phospholene-1-oxide, 1-ethyl-3-methyl-2-phospholene-1-oxide, 3-methyl Phosphorene oxides such as -1-phenyl-2-phospholene-1-oxide, 3-methyl-1-phenyl-3-phospholene-1-oxide or isomers thereof are used.

An oxazolidone ring-containing carbodiimide compound can be produced by reacting the epoxy group of the compound having an epoxy group with the isocyanate group of the carbodiimide compound having an isocyanate group at both ends obtained above. Here, examples of the compound having an epoxy group to be used include the same compounds as those having the epoxy group.

In the above reaction, a compound having a structure represented by the above general formula (1) or (2) is prepared by appropriately adjusting the amount of a carbodiimide compound having an isocyanate group at both ends and a compound having an epoxy group. be able to.

When producing a compound having a structure in which an oxazolidone ring is bonded to both ends of a carbodiimide unit by the above reaction, the equivalent ratio of epoxy group / isocyanate group is preferably 1.0 to 5.0. If the equivalent ratio is less than 1.0, isocyanate groups are likely to remain, and isocyanurate rings are likely to be formed by polymerization of isocyanate groups, and in order to increase the reaction rate of epoxy groups and isocyanate groups. It is better to have an excess of epoxy groups. Moreover, it is because an unreacted epoxy compound will increase too much when an equivalent ratio is larger than 5.0.

The reaction between the carbodiimide compound having an isocyanate group at both ends and the compound having an epoxy group can be carried out by a known method. As a specific reaction method, carbodiimide is prepared by adding the epoxy group-containing compound and the catalyst to the obtained carbodiimide compound having an isocyanate group at both ends and reacting at 110 ° C. to 200 ° C. for 1 to 10 hours. An oxazolidone ring-containing carbodiimide compound having an oxazolidone ring bonded to a unit can be obtained.

Catalysts used in the above reaction include tertiary amines such as triethylamine, tributylamine, dimethylbenzylamine and pyridine, phosphines such as triphenylphosphine and tris (2,6-dimethoxyphenyl) phosphine, tetramethylammonium chloride, benzyl Examples include quaternary ammonium salts such as trimethylammonium chloride, triphenylphosphonium bromide and tetramethylammonium iodide, and Lewis acids such as lithium chloride and aluminum chloride. The amount of catalyst used in the reaction is usually 0.01 to 10 mol%, preferably 0.05 to 5 mol%, based on the isocyanate group.

The structure of the oxazolidone ring-containing carbodiimide compound of the present invention obtained as described above can be confirmed by various analytical methods. For example, the disappearance of the isocyanate group can be confirmed by confirming the change in absorption near 2260 cm ⁻¹ attributed to the isocyanate group in the IR spectrum. In addition, the formation of the oxazolidone ring is possible by confirming the change in absorption near 1750 cm ⁻¹ attributed to the carbonyl group of the oxazolidone ring. In any case, it is not so difficult for those skilled in the art to determine what carbodiimide compound is obtained from the epoxy compound and carbodiimide compound used as raw materials and how the structure is specified.

The oxazolidone ring-containing carbodiimide compound can be suitably used as a curing agent for various uses. A curing agent comprising such an oxazolidone ring-containing carbodiimide compound is also one aspect of the present invention.

The curable resin composition of this invention contains the oxazolidone ring containing carbodiimide compound mentioned above. In the curable resin composition, the oxazolidone ring-containing carbodiimide compound functions as a curing agent. Examples of the curable resin composition include those containing a binder component, a curing agent, and other additives in a state of being dispersed or dissolved in a medium. The curable resin composition is preferably used as a paint.

The binder component is not particularly limited as long as it is a resin having a functional group reactive with a carbodiimide group such as a carboxyl group, and examples thereof include an acrylic resin having a carboxyl group, a polyester resin, a polyurethane resin, and a polyepoxy resin. be able to.

The other additives are not particularly limited, and examples thereof include additives used in the paint field.
The curable resin composition may be any of an organic solvent type, an aqueous type (water-soluble, water-dispersible, emulsion), a non-aqueous dispersion type, and a powder type, and if necessary, a curing catalyst and a surface conditioner. Etc. may be included.

The ratio of the total solid content in the curable resin composition, the resin solid content acid value based on the carboxyl group of the resin, the total amount of carboxyl groups contained in the curable resin composition and the carbodiimide group of the oxazolidone ring-containing carbodiimide compound The solid content molar ratio to the total amount of can be determined appropriately by those skilled in the art. Preferably, the solid content molar ratio between the total amount of carboxyl groups contained in the curable resin composition and the total amount of carbodiimide groups of the carbodiimide compound is blended so that the carboxyl groups are equal to or more than the carbodiimide groups. . The said curable resin composition can be prepared by the method of mixing the component in a composition by a conventionally well-known method, etc.

EXAMPLES Hereinafter, although an Example is hung up and demonstrated in more detail, this invention is not limited only to these Examples. In the examples, “parts” and “%” mean “parts by mass” and “% by mass” unless otherwise specified.

Production Example 1 Production of HMDI carbodiimide solution To 500 ml of Kolben, 2.5 parts of 4-methyl-1-phenyl-3-phospholene-1-oxide was added to 250 parts of 4,4'-dicyclohexylmethane diisocyanate (hereinafter referred to as HMDI). The mixture was stirred at 170 ° C. in a nitrogen stream. Reactor when the carbodiimide value calculated from the isocyanate equivalent obtained by titrating the residual amine was determined by reacting the residual isocyanate group completely with excess n-dibutylamine using bromophenol blue as an indicator. After cooling, 220 parts of N-methylpyrrolidone (hereinafter referred to as NMP) was added to obtain 420 parts of a solution having a solid content of 50%. The average degree of polymerization of the obtained HMDI carbodiimide was 3.1.

Production Example 2 Production of TDI carbodiimide solution Using 200 parts of 2,6-toluene diisocyanate (hereinafter referred to as TDI) in place of HMDI in Production Example 1, 3-methyl-1-phenyl-3-phospholene-1 -Manufactured in the same manner as in Production Example 1 except that 1 part of a xylene solution having an oxide concentration of 1%, the synthesis temperature was changed to 120 ° C, and the diluent solvent was changed to xylene. The average degree of polymerization of the obtained TDI carbodiimide was 3.7.

Production Example 3 Production of HDI carbodiimide solution In Production Example 1, 200 parts of 1,6-hexamethylene diisocyanate (hereinafter referred to as HDI) was used instead of HMDI, and 3-methyl-1-phenyl-3-phospholene- Manufactured in the same manner as in Production Example 1 except that 0.64 parts of a 1-oxide xylene solution having a concentration of 50% was used and xylene was used instead of NMP and the reaction was carried out in xylene at 140 to 150 ° C. The average degree of polymerization of the obtained HDI carbodiimide was 2.4.

Production Example 4 Production of IPDI carbodiimide solution In Production Example 3, 200 parts of isophorone diisocyanate (hereinafter referred to as IPDI) was used instead of HDI, and the concentration of 3-methyl-1-phenyl-3-phospholene-1-oxide was determined. Was produced in the same manner as in Production Example 3 except that 0.49 part of a 50% xylene solution was used. The average degree of polymerization of the obtained IPDI carbodiimide was 4.1.

Production Example 5 Production of TMXDI carbodiimide solution Using 200 parts of tetramethylxylylene diisocyanate (hereinafter referred to as TMXDI) in place of HMDI in Production Example 1, 3-methyl-1-phenyl-3-phospholene-1- Production was carried out in the same manner as in Production Example 1 except that 8 parts of a xylene solution having an oxide concentration of 50% was changed to xylene. The average degree of polymerization of the obtained TMXDI carbodiimide was 3.0.

Production example 6 Production of glycidyl group-containing acrylic resin 65 parts of xylene were charged into a four-necked flask equipped with a stirrer, thermometer, cooler, dropping funnel and nitrogen gas inlet tube, and the temperature was raised to 125C. . A mixture of 47.5 parts of styrene, 47.5 parts of n-butyl acrylate, 5 parts of glycidyl methacrylate and 1.0 part of azobis (2-methyl) butyronitrile was dropped into the dropping funnel over 4 hours while blowing nitrogen gas there. Was further dropped at 90 ° C. for 4 hours, and then cooled to room temperature to obtain a glycidyl group-containing acrylic resin solution (solid content 60%, epoxy equivalent 2840).

Production Example 7 Production of polyol resin 194 parts of trimethylolpropane, 117 parts of hexahydrophthalic anhydride, 84 parts of isophthalic acid, 90 parts of ε-caprolactone, 98 parts of coconut oil, 150 parts of trimellitic anhydride, neodecane To a mixture composed of 300 parts of acid glycidyl ester, 230 parts of butoxyethanol, 120 parts of diethylene glycol dibutyl ether and 0.5 part of dibutyltin oxide were added and reacted at 160 ° C. for 8 hours to obtain a polyol resin. The obtained resin had an acid value of 45, a hydroxyl value of 145, and a solid content of 74%.

Example 1 Production of glycidyl phenyl ether (hereinafter referred to as GPE) terminal-modified HMDI carbodiimide 0.44 parts of lithium chloride, 150 parts of glycidyl phenyl ether, and 429 parts of the HMDI carbodiimide solution of Production Example 1 were sequentially charged into Kolben. . Heat with stirring. Heat was generated when the temperature exceeded 120 ° C, and the temperature rose to about 155 ° C and then decreased to 130 ° C. In the IR spectrum, absorption 2260 cm ⁻¹ of the isocyanate group disappeared and absorption of the carbonyl group of the oxazolidone ring was generated in the vicinity of 1747 cm ⁻¹ . The absorption of the carbodiimide group 2114 cm ⁻¹ did not change. The viscosity of the solution of the obtained GPE terminal-modified HMDI carbodiimide was 798 mPa · s.

Example 2 Production of bisphenol A diglycidyl ether terminal-modified HMDI carbodiimide Example 1 was carried out in the same manner as in Example 1 except that 189 parts of bisphenol A diglycidyl ether was used instead of GPE. The viscosity of the obtained bisphenol A diglycidyl ether terminal-modified HMDI carbodiimide solution was 1100 mPa · s.

Example 3 Production of acrylic resin-modified HMDI carbodiimide In Example 1, 167 parts of the glycidyl group-containing acrylic resin solution of Production Example 6 instead of GPE, 43 parts of the HMDI carbodiimide solution of Production Example 1, lithium chloride 0. The same procedure as in Example 1 was performed except that 09 parts were used. The viscosity of the obtained glycidyl group-containing acrylic resin-modified HMDI carbodiimide solution was 350 mPa · s.

Example 4 Production of GPE terminal-modified TDI carbodiimide 0.44 parts of lithium chloride, 150 parts of glycidyl phenyl ether, and 652 parts of the TDI carbodiimide solution of Production Example 2 were sequentially charged into Kolben. Heat with stirring. Heat was generated when the temperature exceeded 125 ° C., and the temperature rose to 152 ° C. and then decreased to 135 ° C. In the IR spectrum, the absorption of the isocyanate group disappeared, and the absorption of the carbonyl group of the oxazolidone ring was generated, and thus it was cooled. The absorption of carbodiimide groups was not changed. The viscosity of the solution of the obtained GPE terminal-modified TDI carbodiimide was 670 mPa · s.

Example 5 Production of GPE terminal-modified HDI carbodiimide The same procedure as in Example 4 was carried out except that 468 parts of the HDI carbodiimide solution of Production Example 3 was used instead of the TDI carbodiimide solution. The viscosity of the solution of the obtained GPE terminal-modified HDI carbodiimide was 520 mPa · s.

Example 6 Production of GPE terminal-modified IPDI carbodiimide The same procedure as in Example 4 was conducted except that 959 parts of the IPDI carbodiimide solution of Production Example 4 was used instead of the TDI carbodiimide solution. The viscosity of the obtained GPE terminal-modified IPDI carbodiimide solution was 710 mPa · s.

Example 7 Production of GPE terminal-modified TMXDI carbodiimide The same procedure as in Example 4 was repeated except that 844 parts of the TMXDI carbodiimide solution of Production Example 5 was used instead of the TDI carbodiimide solution. The viscosity of the solution of the obtained GPE terminal-modified TMXDI carbodiimide was 620 mPa · s.

Example 8 Cured resin composition 1
A polyol resin solution neutralized by adding 1.96 g of 25% aqueous ammonia to 48.5 g of the polyol resin of Production Example 7 was prepared. While stirring this solution with a disper, 100 g of the GPE terminal-modified HMDI carbodiimide solution synthesized in Example 1 was added. The curable resin composition 1 was obtained by stirring for about 10 minutes. This composition was applied to a tin plate with a # 50 bar coater, set for 10 minutes, and then dried at 150 ° C. for 30 minutes. The obtained coated plate was extracted with acetone and the insoluble residue was measured and found to be 87%.

Example 9 Cured resin composition 2
A polyol resin solution neutralized by adding 2.40 g of 25% aqueous ammonia to 59.5 g of the polyol resin of Production Example 7 was prepared. While stirring this solution with a disper, 100 g of the GPE terminal-modified TDI carbodiimide solution synthesized in Example 1 was added. The curable resin composition 2 was obtained by stirring for about 10 minutes. This composition was applied to a tin plate with a # 50 bar coater, set for 10 minutes, and then dried at 150 ° C. for 30 minutes. The obtained coated plate was extracted with acetone and the insoluble residue was measured and found to be 93%.

The oxazolidone ring-containing carbodiimide compound of the present invention can be favorably used as a curing agent for various applications such as paints, adhesives and coating agents.

Claims (4)

An oxazolidone ring-containing carbodiimide compound having a structure in which an oxazolidone ring is bonded to one or both ends of a carbodiimide unit. An oxazolidone ring-containing carbodiimide compound obtained by reacting a carbodiimide compound having an isocyanate group at a terminal with a compound having an epoxy group. A curing agent comprising the oxazolidone ring-containing carbodiimide compound according to claim 1 or 2. A curable resin composition comprising the oxazolidone ring-containing carbodiimide compound according to claim 1 or 2.