JP2006070186A - Curing agent and two-pack type curable resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a curing agent which can remarkably improve water resistance, wet heat resistance, solvent resistance, chemical resistance, and mechanical properties in spite of being curable at room temperature, and a two-pack type curable resin composition comprising the curing agent. <P>SOLUTION: The curing agent comprises a carbodiimide compound which has at least two carbodiimide groups in the molecule and an isocyanate compound which has at least two isocyanate groups in the molecule and can disperse the carbodiimide compound into a main agent. The two-pack type curable resin composition comprises this curing agent and the main agent. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a curing agent and a two-part curable resin composition, and more particularly to a curing agent and a two-part curable resin composition that are effectively used as a paint, an adhesive, and a coating agent.

In recent years, in the fields of paints, adhesives, coating agents and the like, development of water-based two-component curable resin compositions with little environmental pollution has been actively studied.
Such a two-component curable resin composition includes a water-dispersible main agent and a curing agent for curing the main agent. As the main agent, anionic compounds having a carboxyl group in the molecule are widely used. As anionic main agents, those having improved emulsion stability by combining a small amount of a hydrophilic group such as a hydroxyl group with a carboxyl group have been developed.

On the other hand, the curing agent has been developed mainly for the purpose of imparting various physical properties such as water resistance that is insufficient with the main agent alone while ensuring dispersibility in the main agent.
For example, as a cross-linking agent for a two-part aqueous coating composition mainly composed of a water-dispersed copolymer having a hydroxyl value of 5 to 100 mgKOH / g, water-dispersibility comprising a reaction product of a polyisocyanate compound and an alkoxy polyalkylene glycol A polyisocyanate has been proposed (see, for example, Patent Document 1).

Further, as a curing agent for an aqueous coating composition containing a carboxyl group-containing aqueous resin as a main component, a polysiloxane having at least two carbodiimide groups in one molecule and blocked at one end with a monoalkoxy group having 4 or more carbon atoms. A modified polycarbodiimide compound having an alkylene oxide unit has been proposed (for example, see Patent Document 2).
JP 10-36767 A JP 2000-313825 A

  However, when using a water-dispersible polyisocyanate as described in Patent Document 1 as a curing agent, heat curing is essential in order to sufficiently cure by reacting with the carboxyl group in the main agent. In curing, even if a small amount of hydroxyl group is contained in the main agent, sufficient curing cannot be obtained. Moreover, since an isocyanate group reacts with water other than the carboxyl group in the main ingredient and is consumed, the curing is insufficient. Therefore, it is difficult to improve the water resistance of the obtained cured product (film).

  On the other hand, when a modified polycarbodiimide compound as described in Patent Document 2 is used as a curing agent, the carbodiimide group can react with the carboxyl group even at room temperature to obtain sufficient curing. However, since polycarbodiimide is hydrophobic, it is necessary to modify a large amount of polyalkylene oxide units in order to uniformly disperse it in the main agent. When a large amount of polyalkylene oxide unit is modified, even when the carboxyl group in the main agent is reduced by reaction with the carbodiimide group at the time of curing, hydrophilicity is ensured by the large amount of polyalkylene oxide unit modified in the curing agent. As a result, it is difficult to improve the water resistance.

In addition, since carbodiimide groups have low reactivity with active hydrogen groups such as hydroxyl groups other than carboxyl groups, when these active hydrogen groups are contained in the main agent, they are obtained due to free active hydrogen groups. The water resistance of the cured product (film) to be obtained cannot be improved, and further, the solvent resistance, chemical resistance, mechanical properties, and the like are also defective.
The object of the present invention is a curing agent capable of remarkably improving water resistance, solvent resistance, chemical resistance and mechanical properties even at room temperature curing, and a two-component curing type containing the curing agent. The object is to provide a resin composition.

  In order to achieve the above object, the two-component curable resin composition of the present invention is a two-component curable resin composition comprising a main agent and a curing agent, wherein the curing agent comprises at least two carbodiimides in the molecule. And a carbodiimide compound having a group and an isocyanate compound having at least two isocyanate groups in the molecule and capable of dispersing the carbodiimide compound in the main agent.

Moreover, in the two-component curable resin composition of the present invention, it is preferable that the carbodiimide-based compound has a number average molecular weight of 300 to 10,000.
The curing agent of the present invention is characterized by containing a hydrophobic compound having at least two carbodiimide groups in the molecule and an isocyanate compound having at least two isocyanate groups in the molecule.

Moreover, in the hardening | curing agent of this invention, it is suitable that the said hydrophobic compound is contained 5 to 50weight%.
In the curing agent of the present invention, the isocyanate compound is preferably a water-dispersible polyisocyanate.
Moreover, in the hardening | curing agent of this invention, it is suitable that the said isocyanate type compound contains 5 to 40 weight% of polyethylene oxide units.

  In the curing agent of the present invention, it is preferable that the hydrophobic compound is dispersible in the main agent in the presence of the isocyanate compound.

  Even if the curing agent of the present invention and the two-part curable resin composition containing the curing agent are prepared as an aqueous system, the obtained cured product (film) has water resistance, moist heat resistance, solvent resistance, and chemical resistance. Property and mechanical properties can be remarkably improved.

The two-component curable resin composition of the present invention contains a main agent and a curing agent.
In the present invention, the curing agent includes a carbodiimide compound (corresponding to a hydrophobic compound) having at least two carbodiimide groups in the molecule, and a carbodiimide compound having at least two isocyanate groups in the molecule. And an isocyanate compound that can be dispersed in the main agent.

The carbodiimide-based compound can be prepared, for example, by partially reacting a polyisocyanate compound with a hydrophobic active hydrogen-containing compound and carbodiimidizing the polyisocyanate compound.
The polyisocyanate compound is not particularly limited and is usually used in the production of polyurethane resins. For example, aliphatic polyisocyanate, alicyclic polyisocyanate, araliphatic polyisocyanate, aromatic polyisocyanate and derivatives of these polyisocyanates. And modified products.

  Examples of the aliphatic polyisocyanate include trimethylene diisocyanate, tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 1,2-butylene diisocyanate, 2,3-butylene diisocyanate, Aliphatic diisocyanates such as 1,3-butylene diisocyanate, 2,4,4- or 2,2,4-trimethylhexamethylene diisocyanate, 2,6-diisocyanatomethylcaproate, such as lysine ester triisocyanate, 1, 4,8-triisocyanatooctane, 1,6,11-triisocyanatoundecane, 1,8-diisocyanato-4-isocyanatomethyloctane, 1,3,6-triisocyanatohexane Emissions, 2,5,7 trimethyl-1,8 and aliphatic triisocyanates such as diisocyanato-5-isocyanatomethyl octane.

  Examples of the alicyclic polyisocyanate include 1,3-cyclopentene diisocyanate, 1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate, 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate (common name: Isophorone diisocyanate), 4,4'-methylenebis (cyclohexyl isocyanate), methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 1,3- or 1,4-bis (isocyanatomethyl) cyclohexane ( Common name: hydrogenated xylylene diisocyanate) or mixtures thereof, alicyclic diisocyanates such as norbornane diisocyanate, for example 1,3,5-triisocyanatocyclohexane, 1,3 , 5-trimethylisocyanatocyclohexane, 2- (3-isocyanatopropyl) -2,5-di (isocyanatomethyl) -bicyclo (2.2.1) heptane, 2- (3-isocyanatopropyl) -2 , 6-Di (isocyanatomethyl) -bicyclo (2.2.1) heptane, 3- (3-isocyanatopropyl) -2,5-di (isocyanatomethyl) -bicyclo (2.2.1) heptane 5- (2-isocyanatoethyl) -2-isocyanatomethyl-3- (3-isocyanatopropyl) -bicyclo (2.2.1) heptane, 6- (2-isocyanatoethyl) -2-isocyanate Natomethyl-3- (3-isocyanatopropyl) -bicyclo (2.2.1) heptane, 5- (2-isocyanatoethyl) -2-isocyanatomethyl-2- (3-isocyanato (Lopyl) -bicyclo (2.2.1) -heptane, 6- (2-isocyanatoethyl) -2-isocyanatomethyl-2- (3-isocyanatopropyl) -bicyclo (2.2.1) heptane, etc. And alicyclic triisocyanate.

  Examples of the araliphatic polyisocyanate include 1,3- or 1,4-xylylene diisocyanate or a mixture thereof, ω, ω′-diisocyanato-1,4-diethylbenzene, 1,3- or 1,4-bis ( 1-isocyanato-1-methylethyl) benzene (common name: tetramethylxylylene diisocyanate) or an aromatic aliphatic diisocyanate such as a mixture thereof, for example, an araliphatic triisocyanate such as 1,3,5-triisocyanatomethylbenzene Etc.

  Examples of the aromatic polyisocyanate include m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4′-diphenyl diisocyanate, 1,5-naphthalene diisocyanate, 2,4′- or 4,4′-diphenylmethane diisocyanate or a mixture thereof. 2,4- or 2,6-tolylene diisocyanate or mixtures thereof, aromatic diisocyanates such as 4,4′-toluidine diisocyanate, 4,4′-diphenyl ether diisocyanate, for example, triphenylmethane-4,4 ′, 4 '' -Triisocyanate, 1,3,5-triisocyanatobenzene, 2,4,6-triisocyanatotoluene and other aromatic triisocyanates such as 4,4'-diphenylmethane-2,2 ', 5 5'-tetraisocyanate And aromatic tetraisocyanates such as bets and the like.

Examples of the polyisocyanate derivatives include dimer, trimer, biuret, allophanate, carbodiimide, uretdione, oxadiazine trione, polymethylene polyphenyl polyisocyanate (crude MDI, polymeric MDI), and crude TDI described above. Is mentioned.
Furthermore, as a modified product of polyisocyanate, for example, the above-mentioned polyisocyanate or polyisocyanate derivative and polyols or polyamines are used, and the isocyanate group of polyisocyanate is more than the hydroxyl group of polyols or the amino group of polyamines. In addition, a polyol-modified product, a polyamine-modified product, and the like obtained by reacting at an equivalent ratio that is excessive can be used.

These polyisocyanate compounds may be used alone or in combination of two or more.
Of the above polyisocyanate compounds, preferably isophorone diisocyanate, 4,4′-methylenebis (cyclohexyl isocyanate), 2,4′- or 4,4′-diphenylmethane diisocyanate or a mixture thereof, 2,4- or 2,6 -Tolylene diisocyanate or a mixture thereof, tetramethylxylylene diisocyanate and the like.

  The hydrophobic active hydrogen-containing compound is a hydrophobic compound containing an active hydrogen group capable of reacting with an isocyanate group, such as a hydroxyl group, an amino group, a mercapto group, or a carboxyl group, such as butyl alcohol or hexyl. Alcohol, cyclohexyl alcohol, heptanol, octanol, 2-ethylhexanol, nonyl alcohol, isononyl alcohol, decanol (carbon number 10), lauryl alcohol (carbon number 12), cetyl alcohol (carbon number 14), stearyl alcohol (carbon number 18) ), Oleyl alcohol (carbon number 18), eicosanol (carbon number 20), phenol and derivatives thereof, benzyl alcohol and derivatives thereof, phenethyl alcohol and derivatives thereof, alcohols such as naphthol and derivatives thereof For example, butylamine, hexylamine, cyclohexylamine, octylamine, 2-ethylhexylamine, nonylamine, isononylamine, decylamine (carbon number 10), laurylamine (carbon number 12), cetylamine (carbon number 14), stearylamine ( Monoamines such as carbon number 18), oleylamine (carbon number 18), eicosamine (carbon number 20), dipropylamine, diisopropylamine, dibutylamine, dicyclohexylamine, dioctylamine, aniline and its derivatives, benzylamine and its derivatives, For example, butyl mercaptan, cyclohexyl mercaptan, octyl mercaptan, nonyl mercaptan, decyl mercaptan, dodecyl mercaptan, thiophenol and derivatives thereof. Captan, such, butanoic acid, hexanoic acid, cyclohexane acid, octanoic acid, nonanoic acid, decanoic acid, dodecanoic acid, such as carboxylic acids such as benzoic acid and its derivatives.

These hydrophobic active hydrogen-containing compounds may be used alone or in combination of two or more.
Of the hydrophobic active hydrogen-containing compounds described above, alcohols are preferable, alcohols having 4 to 18 carbon atoms, particularly preferably alcohols having 6 to 18 carbon atoms, and the like.

  In the carbodiimide compound, first, a polyisocyanate compound is partially reacted with a hydrophobic active hydrogen-containing compound, and then the polyisocyanate compound reacted with the hydrophobic active hydrogen-containing compound is carbodiimidized. Alternatively, after the polyisocyanate compound is first carbodiimidized, the remaining isocyanate group of the carbodiimidized polyisocyanate compound is reacted with a hydrophobic active hydrogen-containing compound.

In the former method, the ratio (modification rate) at which the active hydrogen-containing compound is partially reacted with the polyisocyanate compound is such that the reacted active hydrogen-containing compound with respect to the entire carbodiimide compound is, for example, The ratio is 5 to 80% by weight, preferably 7 to 50% by weight.
In the former method, in order to partially react the hydrophobic active hydrogen-containing compound with the polyisocyanate compound, the polyisocyanate compound and the hydrophobic active hydrogen-containing compound are reacted in the above-described ratio. The temperature may be 20 to 150 ° C., preferably 70 to 120 ° C., and the reaction time may be 1 to 10 hours, preferably 1 to 5 hours, for example. As a result, the hydrophobic active hydrogen-containing compound is partially introduced into the isocyanate compound.

In the former method, the isocyanate compound reacted with the active hydrogen-containing compound is then carbodiimidized by a known method, and the isocyanate group may be decarbonized using a carbodiimidization catalyst.
The carbodiimidization catalyst is not particularly limited, but an organic phosphorus compound is preferably used, and a phospholene oxide compound is more preferably used from the viewpoint of catalytic activity.

  Examples of such phospholene oxide compounds include 3-methyl-1-phenyl-2-phospholene-1-oxide, 3-methyl-1-ethyl-2-phospholene-1-oxide, and 1,3-dimethyl. 2-phospholene-1-oxide, 1-phenyl-2-phospholene-1-oxide, 1-ethyl-2-phospholene-1-oxide, 1-methyl-2-phospholene-1-oxide and their double bonds Examples include isomers.

Among such phospholene oxide compounds, 3-methyl-1-phenyl-2-phospholene-1-oxide, which is easily available industrially, is preferable.
These carbodiimidization catalysts may be used alone or in combination of two or more. The ratio of using the carbodiimidization catalyst is preferably 0.01 to 20 parts by weight, more preferably 0.05 to 100 parts by weight with respect to 100 parts by weight of the isocyanate compound reacted with the hydrophobic active hydrogen-containing compound. 10 parts by weight.

  The carbodiimidization is performed using the above-described carbodiimidization catalyst, for example, in an inert gas atmosphere, the reaction temperature is, for example, 30 to 200 ° C., preferably 60 to 180 ° C., and the reaction time is, for example, The reaction is performed for 1 to 50 hours, preferably 3 to 40 hours. As a result, a carbodiimide compound having a hydrophobic group at the molecular end can be obtained.

In such carbodiimidization, the above reaction conditions are controlled so that the average degree of polymerization of the obtained carbodiimide compound, that is, the average number of carbodiimide groups is, for example, 2 to 10, preferably 2 to 5. To do. In such a range of the average degree of polymerization, water dispersibility and crosslinking can be promoted.
In the latter method, in order to carbodiimidize the polyisocyanate compound, the same reaction as described above may be performed using the same carbodiimidization catalyst as described above. Moreover, the average degree of polymerization of the carbodiimide type compound obtained by this is controlled so that it may become 2-10, for example, preferably 2-5 similarly to the above.

  In the latter method, in order to react a hydrophobic active hydrogen-containing compound with the remaining isocyanate group of the carbodiimidized polyisocyanate compound, a carbodiimidized polyisocyanate compound and a hydrophobic active hydrogen-containing compound are mixed. The reaction temperature is, for example, 20 to 150 ° C., preferably 70 to 120 ° C., and the reaction time is, for example, 1 to 10 hours, preferably in the ratio of the active hydrogen groups to the remaining isocyanate groups. Is reacted in 2 to 5 hours. As a result, a carbodiimide compound having a hydrophobic group at the molecular end can be obtained.

In both the former method and the latter method, an organic solvent such as toluene, xylene, ethyl acetate, 2-butanone, acetone, or the like can be used as a reaction medium in carbodiimidization.
Moreover, the number average molecular weight of the obtained carbodiimide type compound is 300-10000, for example.

Moreover, the carbodiimide group equivalent of the obtained carbodiimide type compound is 100-1000, for example, Preferably, it is 150-500.
The isocyanate compound can be obtained by reacting a polyisocyanate compound with a polyoxyethylene-containing compound having both a polyethylene oxide unit and an active hydrogen group capable of reacting with an isocyanate group.

  As the polyisocyanate compound, the same polyisocyanate compound as used in the production of the above-described carbodiimide compound can be used. Preferably, the above-mentioned aliphatic polyisocyanate (particularly, the above-mentioned aliphatic diisocyanate) and / or Examples include the above-described alicyclic polyisocyanates (particularly, the above-described alicyclic diisocyanates), or polyisocyanates containing derivatives or modified products thereof.

More specifically, aliphatic poly (di) isocyanate includes C4-10 alkylene diisocyanate such as hexamethylene diisocyanate. Further, examples of the araliphatic poly (di) isocyanate include isophorone diisocyanate, hydrogenated xylylene diisocyanate, and preferably isophorone diisocyanate.
The derivative or modified product of aliphatic poly (di) isocyanate and / or araliphatic poly (di) isocyanate is preferably a fluid liquid (including viscous liquid) at room temperature (15-30 ° C.), more Specific examples include trimers and allophanates derived from hexamethylene diisocyanate and / or isophorone diisocyanate. In addition, in such aliphatic poly (di) isocyanate and / or araliphatic poly (di) isocyanate derivatives, the isocyanate group content can be selected as appropriate. Preferably, it is 12 to 40 weight%, More preferably, it is 15 to 35 weight%.

The polyoxyethylene-containing compound is not particularly limited, and examples thereof include polyethylene glycol derivatives containing active hydrogen groups and nonionic emulsifiers containing active hydrogen groups.
Examples of polyethylene glycol derivatives containing active hydrogen groups include monoalkoxy ethers such as polyethylene glycol monomethoxy ether, polyethylene glycol monoethoxy ether, polyethylene glycol monopropoxy ether, such as polyethylene glycol monoacetate, polyethylene glycol monopropion. And monoalkoxy esters such as acid esters.

Examples of nonionic emulsifiers containing active hydrogen groups include polyoxyalkylene emulsifiers containing active hydrogen groups such as hydroxyl groups and mercapto groups and having polyoxyethylene units. Preferably, a polyoxyethylene emulsifier containing a hydroxyl group is used.
In the polyoxyalkylene emulsifier, the polyoxyalkylene unit includes, for example, C2-5 alkylene oxides such as oxyethylene, oxypropylene, and oxybutylene, and the polyoxyalkylene unit contains at least oxyethylene. Random copolymerization or block copolymerization of oxyethylene and oxyC3-5 alkylene may be sufficient. The oxyethylene content in the polyoxyalkylene unit is usually 70 to 100 mol%, preferably 80 to 100 mol%.

  More specific examples of such nonionic emulsifiers containing active hydrogen groups include, for example, polyoxyethylene alkyl ethers (for example, polyoxyethylene monooctyl ether, polyoxyethylene monolauryl ether, polyoxyethylene monodecyl ether). , Polyoxyethylene monocetyl ether, polyoxyethylene monostearyl ether, polyoxyethylene C8-24 alkyl ether such as polyoxyethylene monooleyl ether, preferably polyoxyethylene C10-22 alkyl ether, more preferably polyoxyethylene Ethylene C12-18 alkyl ether), polyoxyethylene monoalkyl aryl ether (for example, polyoxyethylene monooctyl phenyl ether, polyoxyethylene monono Polyphenylethylene, polyoxyethylene C8-12 alkyl-C6-12 aryl ether such as polyoxyethylene monodecylphenyl ether), polyoxyethylene sorbitan higher fatty acid ester (polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monostearate) Polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan distearate, polyoxyethylene sorbitan mono-, di- or tri-C10-24 fatty acid ester such as polyoxyethylene sorbitan tristearate), polyoxyethylene mono higher fatty acid Esters (polyoxyethylene mono C10-24 fatty acids such as polyoxyethylene monolaurate and polyoxyethylene monostearate) Ester, etc.), and the like.

Of these nonionic emulsifiers containing an active hydrogen group, polyoxyethylene C8-24 alkyl ether and polyoxyethylene C8-12 alkyl-C6-12 aryl ether are preferable.
Moreover, these polyoxyethylene containing compounds may be used independently and may be used together 2 or more types.

  In order to react the polyisocyanate compound with the polyoxyethylene-containing compound, the equivalent ratio of the isocyanate group of the polyisocyanate compound to the active hydrogen group of the polyoxyethylene-containing compound (isocyanate group / active hydrogen group) exceeds 1. In a proportion, for example, 2-50, preferably 5-30, in a nitrogen atmosphere, the reaction temperature is, for example, 10-150 ° C., preferably 50-100 ° C., and the reaction time is, for example, 1- The reaction may be performed for 10 hours, preferably 2 to 6 hours.

  As a result, an isocyanate compound having an isocyanate group at a molecular end and having a hydrophilicity imparted by introducing a polyethylene oxide unit can be obtained as a water-dispersible polyisocyanate. In the obtained isocyanate compound, the content of the polyethylene oxide unit is, for example, 1 to 40% by weight, preferably 5 to 30% by weight. When the content of the polyethylene oxide unit is less than 5% by weight, sufficient dispersibility of the carbodiimide compound with respect to the main agent may not be obtained. On the other hand, when the content exceeds 40% by weight, the water resistance of the obtained cured product (film) In some cases, problems may arise in the properties and solvent resistance.

Due to the hydrophilicity of the isocyanate compound thus obtained, the carbodiimide compound obtained as described above can be dispersed in the main agent described later.
In addition, the isocyanate group equivalent of the obtained isocyanate type compound is 120-500, for example, Preferably, it is 200-400.
And the hardening | curing agent of this invention contains the carbodiimide type compound obtained by the above, and the isocyanate type compound obtained by the above. The content of the carbodiimide compound and the isocyanate compound is such that the carbodiimide compound is, for example, 5 to 60% by weight, preferably 10 to 40% by weight, and the isocyanate compound is, for example, based on the entire curing agent. 40 to 95% by weight, preferably 50 to 90% by weight.

  Further, the curing agent only needs to contain these carbodiimide compounds and isocyanate compounds. For example, the curing agent may be prepared as a single component by blending a carbodiimide compound and an isocyanate compound, or In preparing the two-component curable resin composition described later, the carbodiimide-based compound and the isocyanate-based compound may be blended with the main agent in the above-described proportions without preparing in advance as a single component. When preparing a single component, it is not particularly limited, and a carbodiimide compound and an isocyanate compound may be mixed and stirred.

Moreover, in a hardening | curing agent, content of a polyethylene oxide unit is 1 to 40 weight%, for example, Preferably, it is 5 to 30 weight%.
In addition, the curing agent can contain a coupling agent that is non-reactive with carbodiimide groups and isocyanate groups in order to further improve water resistance. An example of such a coupling agent is a silane coupling agent.

  Examples of the silane coupling agent include epoxy groups or glycidyl groups such as γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltrimethoxysilane, β- (3,4 epoxycyclohexyl) ethyltrimethoxysilane, and the like. -Containing silane coupling agents, for example, vinyl group-containing silane coupling agents such as vinyltriethoxysilane, vinyltrimethoxysilane, β- (meth) allyloxyethyltrimethoxysilane, and γ- (meth) allyloxypropyltrimethoxysilane Etc.

The blending ratio of the coupling agent is, for example, 0.01 to 30% by weight, preferably 0.1 to 20% by weight, based on the entire curing agent. Further, the coupling agent may be blended in advance with the carbodiimide compound and / or the isocyanate compound as in the preparation of the other components of the curing agent, or may be blended directly with the main agent.
Furthermore, a known external emulsifier, surfactant or compatibilizing agent can be blended in the curing agent in an appropriate blending amount, if necessary.

  In the present invention, the main agent includes an aqueous resin containing at least two or more carboxyl groups in the molecule. Such an aqueous resin is not particularly limited, and examples thereof include polyurethane dispersion, acrylic emulsion, urethane acrylic emulsion, aqueous alkyd resin, and aqueous urethane alkyd resin. These can be used in which an active hydrogen group such as a hydroxyl group is included in the molecule together with a carboxyl group to improve stability.

And the two-component curable resin composition of this invention contains the above-mentioned main ingredient and hardening | curing agent. The compounding ratio of the main agent and the curing agent is, for example, 1 to 40 parts by weight, preferably 5 to 30 parts by weight with respect to 100 parts by weight of the solid content (resin content) of the main agent.
The preparation of the two-component curable resin composition is not particularly limited, and the main agent and the curing agent may be mixed and stirred. In this mixing, the isocyanate compound uniformly disperses the carbodiimide compound in the main agent.

  In the two-part curable resin composition thus obtained, the carboxyl group of the main agent reacts with the carbodiimide group of the carbodiimide compound of the hardener, and the main agent is an active hydrogen group other than the carboxyl group (for example, In the case of having a hydroxyl group), the active hydrogen group reacts with the isocyanate compound of the curing agent, and can be sufficiently cured at a normal temperature in a well-balanced manner. In addition, the pot life is long, and the resulting cured product (film) is excellent in water resistance, moist heat resistance, solvent resistance, chemical resistance, weather resistance, heat resistance, adhesion, and mechanical properties. In addition, it is possible to remarkably improve resistance to moisture and heat, solvent resistance, chemical resistance and mechanical properties.

Therefore, this two-component curable resin composition can be effectively used in various fields such as coating agents such as paints, inks, sealants, adhesives, and nonwoven fabric binders.
For example, when this curing agent is used in an aqueous polyurethane adhesive, the heat and moisture resistance is remarkably improved, and therefore it can be suitably used for wrapping applications, food packaging applications, shoe adhesives, and the like.

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the examples.
Synthesis Example 1 (Synthesis of isocyanate compound)
50 g of 1,6-hexamethylene diisocyanate trimer, 29 g of polyethylene glycol monomethoxy ether (number average molecular weight 400), and 94 g of Emulgen LSS114 (hydroxyl group-containing nonionic emulsifier, manufactured by Kao Corporation) were mixed. Under a nitrogen stream, the reaction was carried out at 90 ° C. for 3 hours to obtain an isocyanate compound A-1. Isocyanate compound A-1 was a transparent liquid having an isocyanate group content of 16.9%.

Synthesis Example 2 (Synthesis of isocyanate compound)
Mixing 650.3 g of 1,6-hexamethylene diisocyanate trimer, 84 g of polyethylene glycol monomethoxy ether (number average molecular weight 400), and 122 g of Emulgen LSS114 (hydroxyl group-containing nonionic emulsifier, manufactured by Kao Corporation) The reaction was carried out at 90 ° C. for 3 hours under a nitrogen stream to obtain an isocyanate compound A-2. Isocyanate compound A-2 was a transparent liquid having an isocyanate group content of 15.4%.

Synthesis Example 3 (Synthesis of carbodiimide compound)
To 435.5 g of tolylene diisocyanate (TDI-80), 162.8 g of 2-ethylhexyl alcohol was added dropwise and mixed so that the liquid temperature did not exceed 90 ° C., and the mixture was further reacted for 1 hour. Thereafter, 200 g of ethyl acetate and 4.4 g of 3-methyl-1-phenyl-2-phospholene-1-oxide (corresponding to 1% by weight with respect to the whole isocyanato group) were added, and a nitrogen stream was added. Below, it was stirred at 80 ° C. for 20 hours to be reacted. After completion of the reaction, it was confirmed by infrared absorption spectrum measurement that the peak of the isocyanate group having an absorption wavelength of 2200 to 2300 cm ⁻¹ had disappeared, and carbodiimide compound C-1 was obtained.

Synthesis Example 4 (Synthesis of carbodiimide compound)
444.8 g of isophorone diisocyanate and 130.2 g of 2-ethylhexyl alcohol were mixed and reacted at 100 ° C. for 2 hours. Thereafter, 8.9 g of 3-methyl-1-phenyl-2-phospholene-1-oxide (corresponding to 2% by weight based on the whole isocyanato group) was added, and the mixture was stirred at 140 ° C. for 15 hours under a nitrogen stream. Stir to react. After completion of the reaction, 300 g of ethyl acetate was added, and it was confirmed by infrared absorption spectrum measurement that the peak of the isocyanate group having an absorption wavelength of 2200 to 2300 cm ⁻¹ had disappeared, and carbodiimide compound C-2 was obtained.

Preparation of Curing Agent Curing agents H-1 to H-7 were prepared according to the formulation in Table 1 below.
In addition, the product B used the trimer of 1, 6- hexamethylene diisocyanate as a hardening | curing agent as it was. For product D, carbodilite V-02 (water-soluble polycarbodiimide, manufactured by Nisshinbo Industries, Inc.) was used as it was as a curing agent.

Examples 1-4 and Comparative Examples 1-4
As the main agent, polyurethane dispersion (solid content 30% by weight, carboxyl group equivalent 3131, hydroxyl group equivalent 0) and aqueous urethane alkyd resin (solid content 40% by weight, carboxyl group equivalent 2500, hydroxyl group equivalent 3014) were cured as described above. The agent was blended as shown in Table 2 to prepare a two-part curable resin composition, and the following evaluation test was performed.

Evaluation test <Dispersibility>
The dispersion state of the curing agent with respect to the main agent when the main agent and the curing agent were blended was visually evaluated.
(Evaluation, ○: good, ×: bad)
<Film forming properties>
The two-part curable resin compositions of Examples and Comparative Examples were applied to a standard test plate (JIS-G-3303 SPTE) using a 250 mil doctor blade, and the coating state at that time was visually evaluated. .
(Evaluation, ○: good, ×: bad)
<Water resistance>
The two-part curable resin compositions of Examples and Comparative Examples were applied to a standard test plate (JIS-G-3303 SPTE) using a 250 mil doctor blade, and dried at room temperature for 7 days to obtain. Distilled water was spotted on the coating film, and changes in the coating film appearance were observed.
(Evaluation, ○: no change, Δ: slight whitening, x: whitening and / or blistering)
<Solvent resistance>
Forming a film from the two-part curable resin compositions of Examples and Comparative Examples, rubbing while pressing the gauze containing 2-butanone on the coating film, until the coating film is peeled off or dissolved The number of times was measured.

<Tensile test>
Films were formed from the two-part curable resin compositions of Examples and Comparative Examples, and the coating films were cut into strips having a width of 10 mm, and the strength and maximum at 100% and 200% elongation were measured using a tensile tester. The strength was measured.
<Glass transition point>
Films were formed from the two-part curable resin compositions of Examples and Comparative Examples, the coatings were cut into strips with a width of 5 mm, and the maximum value of loss tangent during dynamic viscoelasticity measurement was measured. The transition point.

Example 5 and Comparative Example 5 (potential time of mixed liquid)
Using the two-component curable resin composition of Example 1 and Comparative Example 1, after the preparation of the two-component curable resin composition, every 0.5, 3.0, 6.0, 9.0 hours, Using a 250 mil doctor blade, each two-component curable resin composition was applied to a standard test plate (JIS-G-3303 SPTE) and dried at room temperature for 7 days. The solvent resistance was evaluated in the same manner as described above. The results are shown in Table 3 below.

Example 6 and Comparative Example 6 (Adhesion performance evaluation)
In the polyurethane resin aqueous dispersion (solid content 50% by weight, carboxyl group equivalent 12000, hydroxyl group equivalent 12000), a curing agent prepared according to the formulation shown in Table 4 below was blended as shown in Table 5 below. An aqueous polyurethane adhesive (two-component curable resin composition) was prepared, and the following evaluation test was performed.

  As product E, Takenate WD-730 (water dispersible polyisocyanate, manufactured by Mitsui Takeda Chemical Co., Ltd.) was used as it was as a curing agent.

Adhesive performance evaluation Using the aqueous polyurethane adhesive obtained above, high-density foamed EVA (ethylene vinyl acetate copolymer) and soft PVC (polyvinyl chloride) were bonded, and the initial adhesiveness and heat-and-moisture resistance were evaluated. .
That is, a sheet-like high density foamed EVA (30 mm × 100 mm × 10 mm) and a sheet-like soft PVC (30 mm × 100 mm × 2 mm) were prepared as substrates, and both substrates were first thoroughly degreased with ethyl acetate. Subsequently, UV66 (manufactured by TAIWAN MAXBOND) was subjected to primer treatment for high-density foamed EVA, and primer treatment was applied to VC3K (manufactured by TAIWAN MAXBOND) for soft PVC. Next, a water-based polyurethane adhesive was brushed on both substrates, dried at 55 ° C., and this was repeated twice, and then the heat-softened adhesive surfaces were combined and pressure bonded at 40 N / cm for 10 seconds. did.

<Initial adhesiveness>
The 180 ° peel strength (N / cm) and the peel rate of 50 mm / min) were measured after pressing, 1 minute, 10 minutes, and 1 hour, respectively. The results are shown in Table 5.
<Heat and heat resistance>
After standing at room temperature for 5 days, it is stored in a high-humidity machine at 70 ° C. and 95% relative humidity for 7 days. After standing at room temperature for 2 days, 180 ° peel strength N / cm, peel speed 50 mm / min Was measured. The results are shown in Table 5.

Claims (7)

In the two-component curable resin composition comprising the main agent and the curing agent,
The curing agent is a carbodiimide compound having at least two carbodiimide groups in the molecule, and an isocyanate compound having at least two isocyanate groups in the molecule and capable of dispersing the carbodiimide compound in the main agent. And a two-component curable resin composition.   The number average molecular weight of the said carbodiimide type compound is 300-10000, The two-component curable resin composition of Claim 1 characterized by the above-mentioned.   A curing agent comprising a hydrophobic compound having at least two carbodiimide groups in the molecule and an isocyanate compound having at least two isocyanate groups in the molecule.   The curing agent according to claim 3, wherein the hydrophobic compound is contained in an amount of 5 to 50% by weight.   The curing agent according to claim 3 or 4, wherein the isocyanate compound is a water-dispersible polyisocyanate.   The curing agent according to claim 3, wherein the isocyanate compound contains 5 to 40% by weight of a polyethylene oxide unit.   The curing agent according to any one of claims 3 to 6, wherein the hydrophobic compound is dispersible in the main agent in the presence of the isocyanate compound.