WO2021100740A1 - Polycarbodiimide compound, aqueous resin crosslinking agent, aqueous resin composition, and polycarbodiimide compound manufacturing method - Google Patents

Abstract

Provided are an aqueous resin crosslinking agent that is used in the formation of a coating film with superior solvent resistance, and a polycarbodiimide compound that can be used in said aqueous resin crosslinking agent. Specifically provided is the polycarbodiimide compound shown in formula (1). Formula (1): R¹-X¹-(R³-N=C=N)_m-R³-[X³-R⁴-X³-(R³-N=C=N)_n-R³]_p-X²-R² In formula (1), R¹ and R² are each independently a specific residue, R³ is a specific residue, R⁴ is a specific residue, the plurality of R⁴s are the same as or different from one another, at least one of R¹, R², and R⁴ is a residue resulting from excluding an isocyanate group-reactive functional group from a (meth)acrylic polymer having said functional group, X¹, X², and X³ are each independently a specific bond, m and n each represent a number from 1 to 20, and p represents a number from 0 to 20.

Description

Method for Producing Polycarbodiimide Compound, Aqueous Resin Crosslinking Agent, Aqueous Resin Composition and Polycarbodiimide Compound

The present invention relates to a polycarbodiimide compound, an aqueous resin cross-linking agent, an aqueous resin composition, and a method for producing a polycarbodiimide compound.

An aqueous resin cross-linking agent containing a polycarbodiimide compound having a carbodiimide group reacts with a functional group (for example, a carboxyl group) contained in the aqueous resin at a low temperature, and the strength, water resistance, and water resistance of the coating film composed of the aqueous resin and Since it can improve the adhesion characteristics, it has been widely used in the past.
As the polycarbodiimide compound used for such an aqueous resin cross-linking agent, those containing a group derived from a glycol compound as a constituent unit (Patent Document 1) and those containing a group derived from a polyester diol are known (Patent Document 1). Patent Document 2).
Further, an aqueous resin cross-linking agent using a polycarbodiimide compound having two specific types of substituents in combination is also known (Patent Document 3).

JP-A-2018-104605 Japanese Unexamined Patent Publication No. 2015-147838 JP-A-2018-9192

The invention described in Patent Document 1 is made for the purpose that the tensile strength of the coating film formed by using the aqueous resin composition does not decrease before and after the storage of the aqueous resin composition.
On the other hand, in the invention described in Patent Document 2, the molecular design of the polycarbodiimide compound is made for the purpose of preventing hydrolysis of the polyester resin.
Further, the invention described in Patent Document 3 is made so that the function as an aqueous resin cross-linking agent can be exhibited even if it is stored for a long period of time.
However, none of Patent Documents 1 to 3 mentions solvent resistance when a coating film is formed.
Therefore, it is an object of the present invention to provide an aqueous resin cross-linking agent used for forming a coating film having excellent solvent resistance, a polycarbodiimide compound and the like that can be used as the aqueous resin cross-linking agent.

As a result of intensive research to solve the above problems, the present inventor can solve the above problems by including a structural unit derived from a specific (meth) acrylic polymer in the molecule of the polycarbodiimide compound. And completed the present invention.

The present invention is as follows.
[1] A polycarbodiimide compound represented by the following formula (1).
R ¹ -X ^1- (R ³ -N = C = N) _m -R ^3- [X ³ -R ⁴ -X ^3- (R ³ -N = C = N) _n -R ³ ] _p -X ² -R ² (1)
In equation (1)
R ¹ and R ² are residues obtained by removing one of the functional groups from an organic compound having at least one functional group having reactivity with an isocyanate group, respectively.
R ³ is a divalent residue obtained by removing two isocyanate groups from the diisocyanate compound, and the diisocyanate compound contains an aliphatic hydrocarbon group or an alicyclic hydrocarbon group that directly bonds with the two isocyanate groups. a plurality of ^{R 3,} equal to or different from each other,
R ⁴ is a residue obtained by removing the functional group a functional group having a reactivity of an organic compound having two isocyanate groups, a plurality of R ^4, equal to or different from each other,
At ^{least one of R 1} , R ² and R ⁴ is a residue obtained by removing the functional group from a (meth) acrylic polymer having a functional group reactive with an isocyanate group.
X ¹ , X ² and X ³ are bonds formed independently by the reaction of the functional group of the organic compound with the isocyanate group of the diisocyanate compound.
m and n represent numbers from 1 to 20, respectively.
p represents a number from 0 to 20.
[2] The polycarbodiimide compound according to [1], which is represented by the following formula (1-2).
R ¹ -X ^1- (R ³ -N = C = N) _m -R ³ -X ² -R ² (1-2)
In equation (1-2)
R ¹ and R ² are residues obtained by removing one of the functional groups from an organic compound having at least one functional group having reactivity with an isocyanate group, respectively.
R ³ is a divalent residue obtained by removing two isocyanate groups from the diisocyanate compound, and the diisocyanate compound contains an aliphatic hydrocarbon group or an alicyclic hydrocarbon group that directly bonds with the two isocyanate groups. a plurality of ^{R 3,} equal to or different from each other,
The organic compound having at least one functional group reactive with the isocyanate group comprises a (meth) acrylic polymer having at least one functional group reactive with the isocyanate group.
X ¹ and X ² are bonds formed independently by the reaction of the functional group of the organic compound with the isocyanate group of the diisocyanate compound.
m represents a number from 1 to 20.
[3] A group in which an organic compound having at least one functional group reactive with the isocyanate group is further composed of compounds represented by the following formulas (2), (3), (4) and (5). The polycarbodiimide compound according to [2], which comprises one or more compounds selected from.
R ^5- (O-CH _2- CHR ⁶ ) _p- Z ¹ (2)
(In the formula, R ⁵ is an alkyl group having 1 to 4 carbon atoms, R ⁶ is a hydrogen atom or a methyl group, Z ¹ is OH or NH ₂ , and p is an integer of 4 to 30.)
(R ⁷ ) ₂ N-R ^8- OH (3)
(In the formula, R ⁷ is independently an alkyl group having 1 to 6 ^{carbon atoms, and R 8} is an alkylene group having 1 to 10 carbon atoms or a polyoxyalkylene group.)
(R ⁹ ) ₂ N-R ^10- NH ₂ (4)
(In the formula, R ⁹ is independently an alkyl group having 1 to 6 ^{carbon atoms, and R 10} is an alkylene group having 1 to 10 carbon atoms or a polyoxyalkylene group.)
_{^{Z 2 -R 11 -SO 3 M (}} 5)
(In the formula, R ¹¹ is an alkylene group having 1 to 10 carbon atoms, M is an alkali metal, and Z ² is OH or NH _2. )
[4] The organic compound having at least one functional group reactive with the isocyanate group contains only a (meth) acrylic polymer having at least one functional group reactive with the isocyanate group [2]. ] The polycarbodiimide compound according to.
[5] In the above formula (1),
R ¹ and R ² are residues obtained by removing one of the functional groups from an organic compound having at least one functional group having reactivity with an isocyanate group, respectively.
R ³ is a divalent residue obtained by removing two isocyanate groups from the diisocyanate compound, and the diisocyanate compound contains an aliphatic hydrocarbon group or an alicyclic hydrocarbon group that directly bonds with the two isocyanate groups. a plurality of ^{R 3,} equal to or different from each other,
R ⁴ is a residue obtained by removing the functional group from the (meth) acrylic polymer having two functional groups reactive with the isocyanate group.
X ¹ and X ² are bonds formed independently by the reaction of the functional group of the organic compound with the isocyanate group of the diisocyanate compound.
X ³ is a bond formed by the reaction of the functional group of the (meth) acrylic polymer having two functional groups having reactivity with the isocyanate group independently and the isocyanate group of the diisocyanate compound. ,
m and n represent numbers from 1 to 20, respectively.
p represents a number from 1 to 20
The organic compound having a functional group having reactivity with the isocyanate group is one or more selected from the group consisting of the compounds represented by the following formulas (2), (3), (4) and (5). The polycarbodiimide compound according to [1], which is a compound.
R ^5- (O-CH _2- CHR ⁶ ) _p- Z ¹ (2)
(In the formula, R ⁵ is an alkyl group having 1 to 4 carbon atoms, R ⁶ is a hydrogen atom or a methyl group, Z ¹ is OH or NH ₂ , and p is an integer of 4 to 30.)
(R ⁷ ) ₂ N-R ^8- OH (3)
(In the formula, R ⁷ is independently an alkyl group having 1 to 6 ^{carbon atoms, and R 8} is an alkylene group having 1 to 10 carbon atoms or a polyoxyalkylene group.)
(R ⁹ ) ₂ N-R ^10- NH ₂ (4)
(In the formula, R ⁹ is independently an alkyl group having 1 to 6 ^{carbon atoms, and R 10} is an alkylene group having 1 to 10 carbon atoms or a polyoxyalkylene group.)
_{^{Z 2 -R 11 -SO 3 M (}} 5)
(In the formula, R ¹¹ is an alkylene group having 1 to 10 carbon atoms, M is an alkali metal, and Z ² is OH or NH _2. )
[6] In the above formula (1),
R ¹ and R ² are residues obtained by removing the functional group from the (meth) acrylic polymer having at least one functional group reactive with the isocyanate group, respectively.
R ³ is a divalent residue obtained by removing two isocyanate groups from the diisocyanate compound, and the diisocyanate compound contains an aliphatic hydrocarbon group or an alicyclic hydrocarbon group that directly bonds with the two isocyanate groups. a plurality of ^{R 3,} equal to or different from each other,
R ⁴ is a residue obtained by removing the functional group from the (meth) acrylic polymer having two functional groups reactive with the isocyanate group.
X ¹ and X ² are each independently formed by the reaction of the functional group of the (meth) acrylic polymer having at least one functional group having reactivity with the isocyanate group with the isocyanate group of the diisocyanate compound. Is a combination
X ³ is a bond formed by the reaction of the functional group of the (meth) acrylic polymer having two functional groups having reactivity with the isocyanate group independently and the isocyanate group of the diisocyanate compound. ,
m and n represent numbers from 1 to 20, respectively.
The polycarbodiimide compound according to [1], wherein p represents a number from 1 to 20.
[7] In the above formula (1),
R ¹ and R ² are residues obtained by removing the functional group from an organic compound having at least one functional group reactive with an isocyanate group, respectively, and the organic compound is reactive with an isocyanate group. Contains a (meth) acrylic polymer having at least one functional group having
R ³ is a divalent residue obtained by removing two isocyanate groups from the diisocyanate compound, and the diisocyanate compound contains an aliphatic hydrocarbon group or an alicyclic hydrocarbon group that directly bonds with the two isocyanate groups. a plurality of ^{R 3,} equal to or different from each other,
R ⁴ is a functional group obtained by removing the functional group from a divalent organic compound having two functional groups reactive with an isocyanate group, and the divalent organic compound is a glycol compound or a dicarboxylic acid compound. Yes,
X ¹ and X ² are each independently formed by the reaction of the functional group of the (meth) acrylic polymer having at least one functional group having reactivity with the isocyanate group with the isocyanate group of the diisocyanate compound. Is a combination
X ³ is a urethane bond,
m and n represent numbers from 1 to 20, respectively.
The polycarbodiimide compound according to [1], wherein p represents a number from 1 to 20.
[8] A divalent organic compound having two functional groups reactive with the isocyanate group is a glycol compound, and the glycol compound is ethylene glycol, propylene glycol, 1,4-butanediol, diethylene glycol, or diethylene glycol. The polycarbodiimide compound according to [7], which is one or more selected from the group consisting of propylene glycol, triethylene glycol, tripropylene glycol, polyethylene glycol, and polypropylene glycol.
[9] The ^{X 3} is any group represented by the following formula (6) to (8), [1], polycarbodiimide compound of any of [5] and [6].

[10] The polycarbodiimide compound according to any one of [1] to [9], ^{wherein X 1} and X ^{2 are any group represented by the following formulas (6) to (8).}

[11] The diisocyanate compounds are hexamethylene diisocyanate, cyclohexane-1,4-diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, methylcyclohexanediisocyanate, and 2,5 (2,6) -bis (isocyanate). The polycarbodiimide compound according to any one of [1] to [10], which is one or more selected from the group consisting of natomethyl) bicyclo [2.2.1] heptane.
[12] An aqueous resin cross-linking agent containing the polycarbodiimide compound according to any one of [1] to [11] and an aqueous medium.
[13] An aqueous resin composition containing the polycarbodiimide compound according to any one of [1] to [11] and an aqueous resin.
[14] A method for producing a polycarbodiimide compound represented by the following formula (1), which comprises the following steps (A) and (B).
Step (A): Carbodiimide reaction of the diisocyanate compound in the presence of a catalyst to obtain a polycarbodiimide precursor having isocyanate groups at both ends Step (B): Having at least one functional group capable of reacting with the isocyanate group The polycarbodiimide is a residue obtained by removing the functional group from the (meth) acrylic polymer and / or a residue obtained by removing the functional group from the (meth) acrylic polymer having two functional groups capable of reacting with an isocyanate group. Reaction process for introduction into the precursor R ¹ -X ^1- (R ³ -N = C = N) _m -R ^3- [X ³ -R ⁴ -X ^3- (R ³ -N = C = N) _n -R ³ ] _p -X ² -R ² (1)
In equation (1)
R ¹ and R ² are residues obtained by removing one of the functional groups from an organic compound having at least one functional group having reactivity with an isocyanate group, respectively.
R ³ is a divalent residue obtained by removing two isocyanate groups from the diisocyanate compound, and the diisocyanate compound contains an aliphatic hydrocarbon group or an alicyclic hydrocarbon group that directly bonds with the two isocyanate groups. a plurality of ^{R 3,} equal to or different from each other,
R ⁴ is a residue obtained by removing the functional group a functional group having a reactivity of an organic compound having two isocyanate groups, a plurality of R ^4, equal to or different from each other,
At ^{least one of R 1} , R ² and R ⁴ is a residue obtained by removing the functional group from a (meth) acrylic polymer having a functional group reactive with an isocyanate group.
X ¹ , X ² and X ³ are bonds formed independently by the reaction of the functional group of the organic compound with the isocyanate group of the diisocyanate compound.
m and n represent numbers from 1 to 20, respectively.
p represents a number from 0 to 20.

According to the present invention, it is possible to provide an aqueous resin composition having high solvent resistance, an aqueous resin cross-linking agent used in the resin composition, and a polycarbodiimide compound used in the aqueous resin cross-linking agent.

Hereinafter, the present invention will be described based on specific embodiments. In addition, in this specification, "(meth) acrylic" includes both "acrylic" and "methacryl". Further, the "(meth) acrylic polymer" includes not only a homopolymer but also a copolymer.

<Polycarbodiimide compound>
The present invention relates to a polycarbodiimide compound represented by the following formula (1).
R ¹ -X ^1- (R ³ -N = C = N) _m -R ^3- [X ³ -R ⁴ -X ^3- (R ³ -N = C = N) _n -R ³ ] _p -X ² -R ² (1)
In equation (1)
R ¹ and R ² are residues obtained by removing one of the functional groups from an organic compound having at least one functional group having reactivity with an isocyanate group, respectively.
R ³ is a divalent residue obtained by removing two isocyanate groups from the diisocyanate compound, and the diisocyanate compound contains an aliphatic hydrocarbon group or an alicyclic hydrocarbon group that directly bonds with the two isocyanate groups. a plurality of ^{R 3,} equal to or different from each other,
R ⁴ is a residue obtained by removing the functional group a functional group having a reactivity of an organic compound having two isocyanate groups, a plurality of R ^4, equal to or different from each other,
At ^{least one of R 1} , R ² and R ⁴ is a residue obtained by removing the functional group from a (meth) acrylic polymer having a functional group reactive with an isocyanate group.
X ¹ , X ² and X ³ are bonds formed independently by the reaction of the functional group of the organic compound with the isocyanate group of the diisocyanate compound.
m and n represent numbers from 1 to 20, respectively.
p represents a number from 0 to 20.

In the polycarbodiimide compound represented by the formula (1), ^{at least one of R 1} , R ² and R ⁴ excludes the functional group from the (meth) acrylic polymer having a functional group reactive with the isocyanate group. It is important that it is a residue.
In the polycarbodiimide compound represented by the formula (1), the peak intensity ratio of the carbonyl group (1720 cm ^-1 ) to the peak intensity ratio of the ^{carbodiimide group (2112 cm-1) measured by infrared absorption (IR) spectrum measurement is} It is preferably 0.2 to 8.
This peak intensity ratio is an index of the ratio of residues of the polycarbodiimide compound represented by the formula (1) excluding the functional group from the (meth) acrylic polymer having a functional group reactive with the isocyanate group. Is what becomes. This peak intensity ratio has the same meaning in the following other embodiments.
The following embodiment, assuming that one or both of R ¹ and R ² contains a residue obtained by removing the functional group from a (meth) acrylic polymer having a functional group reactive with an isocyanate group. 1, 2, 4 and 5 can be mentioned.
Examples 3 and 4 below include those in which R ⁴ is a residue obtained by removing the functional group from a (meth) acrylic polymer having two functional groups having reactivity with an isocyanate group. Can be done.
The following embodiments include those in which all of R ¹ , R ² and R ⁴ are residues obtained by removing the functional group from a (meth) acrylic polymer having a functional group reactive with an isocyanate group. 4 can be mentioned.

In the above formula (1), examples of the functional group of the (meth) acrylic polymer having a functional group having reactivity with the isocyanate group include a hydroxyl group and a carboxyl group, and a hydroxyl group is preferable.
When ^{one or both of R 1} and R ² are residues obtained by removing the functional group from a (meth) acrylic polymer having a functional group reactive with an isocyanate group, the (meth) acrylic polymer is It has at least one functional group.
When R ⁴ contains a residue obtained by removing the functional group from a (meth) acrylic polymer having a functional group reactive with an isocyanate group, the number of the functional groups in the (meth) acrylic polymer is 2. It is one.

In the formula (1), m and n represent numbers from 1 to 20, respectively, and are preferably 2 to 10.
In the formula (1), when p is 0, the compound is represented by the formula (1-2) represented by the following embodiment 1.

In the general formula (1), the organic compound having at least one functional group reactive with an isocyanate group, which forms the residues of ^{R 1} and R ^{2, has a functional group reactive with an isocyanate group.} As a specific example of the organic compound when it is not a (meth) acrylic polymer having at least one, for example, one or more of the compounds represented by the following formulas (2), (3), (4) and (5). Can be mentioned.

^{Compound R 5-} (O-CH _2- CHR ⁶ ) _p- Z ¹ (2) represented by the formula (2)
(In the formula, R ⁵ is an alkyl group having 1 to 4 carbon atoms, R ⁶ is a hydrogen atom or a methyl group, Z ¹ is OH or NH ₂ , and p is an integer of 4 to 30.)
Examples of the alkyl group having 1 to 4 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, an isobutyl group, and a t-butyl group.
A methyl group is preferable as ^{R 5} , and a hydrogen atom is preferable as ^{R 6.}
p is an integer of 4 to 30, and is preferably an integer of 7 to 25, more preferably an integer of 8 to 20, from the viewpoint of improving the affinity between the polycarbodiimide compound and the carboxyl group-containing aqueous resin.

Compound represented by formula (3) (R ⁷ ) ₂ N-R ^8- OH (3)
(In the formula, R ⁷ is independently an alkyl group having 1 to 6 ^{carbon atoms, and R 8} is an alkylene group having 1 to 10 carbon atoms or a polyoxyalkylene group.)
Examples of the alkyl group having 1 to 6 carbon atoms of R ⁷ include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, an isobutyl group, a t-butyl group, and an n-. Examples thereof include a pentyl group, an n-hexyl group and a cyclohexyl group. Of these, a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an s-butyl group, an isobutyl group, and a t-butyl group are preferable.
Examples of the alkylene group having 1 to 10 carbon atoms of R ⁸ include a methylene group, an ethylene group, a propylene group, a tetramethylene group, a pentamethylene group, a hexamethylene group, a heptamethylene group, an octamethylene group, a nonamethylene group, and a decamethylene group. The group etc. can be mentioned. The hydrogen atom of the alkylene group may be substituted with a monovalent hydrocarbon group such as a methyl group.
As R ^8, a ethylene group, propylene group, tetramethylene group, pentamethylene group is preferable.

Compound represented by formula (4) (R ⁹ ) ₂ N-R ^10- NH ₂ (4)
(In the formula, R ⁹ is independently an alkyl group having 1 to 6 ^{carbon atoms, and R 10} is an alkylene group having 1 to 10 carbon atoms or a polyoxyalkylene group.)
Examples of the alkyl group having 1 to 6 carbon atoms of R ^{9 are the same as those of R 7} described above. Among them, a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an s-butyl group and an isobutyl group. , And t-butyl groups are preferred.
Examples of the alkylene group having 1 to 10 carbon atoms of R ¹⁰ include the same groups as those of ^{R 8.}
The R ^10, an ethylene group, a propylene group, a tetramethylene group, a pentamethylene group is preferable.

Wherein the compound represented by ^{(5) Z 2 -R 11 -SO} 3 M (5)
(In the formula, R ¹¹ is an alkylene group having 1 to 10 carbon atoms, M is an alkali metal, and Z ² is OH or NH _2. )
Examples of the alkylene group having 1 to 10 carbon atoms of R ¹¹ include the same groups as those of ^{R 8.} Of these, a methylene group and an ethylene group are preferable.

<(Meta) acrylic polymer having a functional group reactive with an isocyanate group>
In the general formula (1), a (meth) acrylic polymer having at least one functional group reactive with an isocyanate group capable of forming residues of ^{R 1} and R ^{2 and a formula (1).} in, it is possible to form the residue of R ^4, is described functional groups having two (meth) acrylic polymer having a reactivity with the isocyanate groups.
Examples of the functional group include a hydroxyl group or a carboxyl group.
In these polymers, when the functional group having reactivity with the isocyanate group is a hydroxyl group or a carboxyl group, it can be obtained by, for example, the following production method.
For example, as described in International Publication No. 2017/043373, in the presence of an inert gas containing 0.01 to 6.0% by volume of oxygen, a functional group and a thiol group having a reactivity with an isocyanate group A method of producing a (meth) acrylic polymer having a functional group having a reactivity with an isocyanate group by polymerizing a monomer mixture containing a (meth) acrylic monomer with a compound having (meth) acrylic monomer as a starting species can be mentioned. it can.
In the above production method, the polymerization reaction of the monomer mixture containing the (meth) acrylic monomer is carried out in the presence of a metallocene-based catalyst, and the metallocene-based catalyst is formed with the monomer mixture containing the (meth) acrylic monomer and the isocyanate group. It is preferable to use the compound in the range of 0.001 to 5.0 parts by mass with respect to a total of 100 parts by mass of the compound having the reactive functional group and the thiol group.
Further, in the above production method, the isocyanate group is based on 100 parts by mass of the total of the monomer mixture containing the (meth) acrylic monomer and the compound having a functional group and a thiol group reactive with the isocyanate group. It is preferable to use a compound having a functional group and a thiol group reactive with the above in an amount in the range of 0.1 to 50 parts by mass.
Moreover, it is preferable that the above-mentioned production method carries out a polymerization reaction by a massive polymerization method. This polymerization reaction is usually carried out under normal pressure conditions, but may be carried out under pressurized conditions or reduced pressure conditions.
The reaction temperature is usually set to a temperature in the range of 60 to 200 ° C. The reaction time is usually set in the range of 30 minutes to 24 hours.

As the compound having a functional group having a reactivity with an isocyanate group and a thiol group used as the starting species, when the functional group having a reactivity with an isocyanate group is a hydroxyl group, mercaptoethanol, 1-mercaptoethanol, 2 -Mercaptoethanol, 1-mercaptopropanol, 3-mercaptopropanol, 1-mercapto-2,3-propanediol, 1-mercapto-2-butanol, 1-mercapto-2,3-butanediol, 1-mercapto-3, 4-Butandiol, 1-mercapto-3,4,4'-butantriol, 2-mercapto-3-butanol, 2-mercapto-3,4-butanediol and 2-mercapto-3,4,4'-butane Examples thereof include triol and thioglycerol hydroxyl group-containing thiol compounds.
When the functional group having reactivity with the isocyanate group used as the starting species is a carboxyl group, α-mercaptopropionic acid, β-mercaptopropionic acid, 2,3-di Mercaptopropionic acid, thioglycolic acid, o-mercaptobenzoic acid, m-mercaptobenzoic acid, thioapple acid, thiolcarbonate, o-thiokumalic acid, α-mercaptobutanoic acid, β-mercaptobutanoic acid, γ-mercaptobutanoic acid, thio Carboxylic group-containing compounds such as histidine and 11-mercaptobenzoic acid can be mentioned.
Examples of the (meth) acrylic monomer contained in the monomer mixture containing the (meth) acrylic monomer include (meth) acrylic acid alkyl ester.
The alkyl chain in the (meth) acrylic acid alkyl ester may be linear or branched, and examples thereof include an alkyl chain having 1 to 36 carbon atoms. Specific examples of the (meth) acrylic acid alkyl ester include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, pentyl (meth) acrylate, and (meth). ) Hexyl acrylate, -2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, lauryl (meth) acrylate, Stearyl (meth) acrylate, icosyl (meth) acrylate, docosyl (meth) acrylate, isostearyl (meth) acrylate, octadecyl (meth) acrylate, heptadecyl (meth) acrylate, behenyl (meth) acrylate, etc. Can be mentioned. These may be used alone or in combination of two or more.

Other than these (meth) acrylic acid alkyl esters, for example, (meth) acrylic acid having a hydroxyl group or a carboxyl group or an ester thereof can also be mentioned.
Examples of the monomer of the (meth) acrylic acid ester having a hydroxyl group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroshikibutyl (meth) acrylate, and 6-hydroxyhexyl (meth). ) Acrylate, 8-hydroxyoctyl (meth) acrylate and the like. The hydroxyl group-containing monomer may be used alone or in combination of two or more.
Examples of the monomer of (meth) acrylic acid having a carboxyl group include ethylenically unsaturated carboxylic acids such as (meth) acrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid and citraconic acid. Examples of the monomer of the (meth) acrylic acid ester having a carboxyl group include (meth) acrylic acid β-carboxyethyl, (meth) acrylic acid 5-carboxypentyl, succinate mono (meth) acryloyloxyethyl ester and ω-carboxypoly. Carboxyl group-containing (meth) acrylates such as caprolactone mono (meth) acrylate can be mentioned. The carboxyl group-containing monomer may be used alone or in combination of two or more.

Specific examples of the metallocene-based catalyst include dicyclopentadiene-Ti-dichloride, dicyclopentadiene-Ti-bisphenyl, dicyclopentadiene-Ti-bis-2,3,4,5,6-pentafluoropheni-1. -Il, dicyclopentadiene-Ti-bis-2,3,5,6-tetrafluoropheni-1-yl, dicyclopentadiene-Ti-bis-2,5,6-trifluoropheni-1-yl, di Cyclopentadiene-Ti-bis-2,6-difluoropheni-1-yl, dicyclopentadiene-Ti-bis-2,4-difluoropheni-1-yl, dimethylcyclopentadiene-Ti-bis-2,3 , 4,5,6-pentafluoropheni-1-yl, dimethylcyclopentadiene-Ti-bis-2,3,5,6-tetrafluoropheni-1-yl, dimethylcyclopentadiene-Ti-bis Titanocene compounds such as -2,6-difluoropheni-1-yl, dimethylcyclopentadieneyl-Ti-bis-2,6-difluoro-3- (pill-1-yl) -pheni-1-yl; Dicyclopentadiene compounds such as cyclopentadieneyl-Zr-dichloride, dimethylcyclopentadieneyl-Zr-dichloride; and ruthenocene compounds, cromonocene compounds, cobaltene compounds and the like can be mentioned. These metallocene catalysts can be used alone or in combination.

Examples of the (meth) acrylic polymer having a functional group having reactivity with an isocyanate group include those having at least one of the functional groups and those having two of the functional groups, and the former is expressed by the formula (1). ) Can be used as an organic compound for forming ^{R 1} and R ² , and the latter can be used as an organic compound for forming ^{R 4 of the formula (1).}
Further, as the (meth) acrylic polymer having at least one functional group having reactivity with an isocyanate group, those having one functional group can be preferably exemplified. This also applies to the following specific embodiments. Further, as a (meth) acrylic polymer having at least one functional group having reactivity with an isocyanate group, for example, 4 can be mentioned as the upper limit of the number of the functional groups.
Whether the (meth) acrylic polymer has at least one functional group or two functional groups can be adjusted by appropriately selecting a monomer. it can.

Examples of the (meth) acrylic polymer having at least one functional group include Actflow ™ UMM-1001, UT-1001, CB-3060, CB-3098, and CBB-3098 manufactured by Soken Kagaku Co., Ltd. Can be done. Among these, UT-1001 can be mentioned as a (meth) acrylic polymer having two functional groups.

The average molecular weight of the (meth) acrylic polymer having a functional group reactive with the isocyanate group can be about 300 to 4000 in terms of weight average molecular weight. The average molecular weight can be measured in terms of standard polystyrene using a gel permeation chromatography method (GPC method).

<Diisocyanate compound>
In the general formula (1), the diisocyanate compound forming ^{R 3 will be described.}
R ³ is a divalent residue obtained by removing two isocyanate groups from the diisocyanate compound, and the diisocyanate compound has an aliphatic hydrocarbon group or an alicyclic hydrocarbon group that directly bonds with the two isocyanate groups. Have. A plurality of ^{R 3} are the same or different from each other.
Specific examples of the diisocyanate compound include hexamethylene diisocyanate, cyclohexane-1,4-diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, methylcyclohexanediisocyanate, and 2,5 (2,6) -bis (isocyanate). Natomethyl) bicyclo [2.2.1] heptane and the like can be mentioned.
Among these, dicyclohexylmethane-4,4'-diisocyanate is preferable from the viewpoint of ease of synthesis of the polycarbodiimide compound, storage stability of the synthesized polycarbodiimide compound, and availability.

In the general formula (1), X ¹ , X ² and X ³ are each independently a functional group of an organic compound having a functional group reactive with an isocyanate group and an isocyanate group of the diisocyanate compound. It is a bond formed by the reaction.
X ¹ and X ² are groups formed by reaction with an organic compound forming ^{R 1} and R ^{2 , and X 3} is a group formed by reaction with an organic compound forming ^{R 4.}
For example, when a (meth) acrylic polymer having at least one hydroxyl group or a compound represented by the formula (3) is used as the organic compound forming ^{X 1} and X ^{2, the functional group of these organic compounds is a hydroxyl group.} Therefore, when the diisocyanate group reacts, urethane bonds represented by the following formula (6) are formed as ^{X 1} and X ^2. The same applies to the case where the compounds represented by the formulas (2) and (5) in which Z ¹ and Z ^{2 are OH, respectively, are used.}

On the other hand, ^{when a compound represented by the formula (4) is used as the organic compound forming X 1} and X ² , the functional group of the organic compound is an amino group, and when this reacts with the diisocyanate group, X ¹ , X ² forms a urea bond represented by the following formula (7). The same applies to the case where the compounds represented by the formulas (2) and (5) in which Z ¹ and Z ² are NH _{2 respectively are used.}

Further, when ^{a (meth) acrylic polymer having at least one carboxyl group is used as the organic compound forming X 1} and X ² , since the functional group of this organic compound is a carboxyl group, this reacts with the diisocyanate group. Then, as X ¹ and X ² , an amide bond represented by the following formula (8) is formed.

On the other hand, when ^{a (meth) acrylic polymer having two hydroxyl groups or another divalent glycol compound is used as the organic compound forming X 3} , since the functional group of these organic compounds is a hydroxyl group, the diisocyanate group and the diisocyanate group are used. There when reacted, as X ^3, a urethane bond represented by formula (6) is formed.
When a (meth) acrylic polymer having two carboxyl groups or another dicarboxylic acid compound is used as the organic compound forming ^{X 3, the functional group of these organic compounds is a carboxyl group, so this and diisocyanate.} When the group reacting, as X ^3, amide bond represented by formula (8) is formed.

The carbodiimide equivalent (chemical formula amount per 1 mol of carbodiimide group) of the polycarbodiimide compound represented by the formula (1) of the present invention is preferably 100 to 2500, more preferably 150 to 2000, and further preferably 200 to 1500.

Hereinafter, specific embodiments included in the above formula (1) will be described.
<First Embodiment>
As the first embodiment of the polycarbodiimide of the present invention, a compound represented by the following formula (1-2) can be mentioned.
R ¹ -X ^1- (R ³ -N = C = N) _m -R ³ -X ² -R ² (1-2)
In equation (1-2)
R ¹ and R ² are residues obtained by removing one of the functional groups from an organic compound having at least one functional group having reactivity with an isocyanate group, respectively.
R ³ is a divalent residue obtained by removing two isocyanate groups from the diisocyanate compound, and the diisocyanate compound contains an aliphatic hydrocarbon group or an alicyclic hydrocarbon group that directly bonds with the two isocyanate groups. a plurality of ^{R 3,} equal to or different from each other,
The organic compound having at least one functional group reactive with the isocyanate group comprises a (meth) acrylic polymer having at least one functional group reactive with the isocyanate group.
X ¹ and X ² are bonds formed independently by the reaction of the functional group of the organic compound with the isocyanate group of the diisocyanate compound.
m represents a number from 1 to 20, respectively.

In the above formula (1-2), ^{as an organic compound having a functional group having reactivity with an isocyanate group forming R 1} and R ² , it has at least one functional group having reactivity with an isocyanate group (meth). ) Contains acrylic polymer. The organic compound having a functional group having reactivity with an isocyanate group may be only the (meth) acrylic polymer, or may contain other organic compounds.
As the (meth) acrylic polymer having at least one functional group having reactivity with an isocyanate group, the one described in the above <(meth) acrylic polymer having a functional group having reactivity with an isocyanate group> is used. be able to. The functional group of the (meth) acrylic polymer is preferably a hydroxyl group or a carboxyl group.
In a first embodiment, at the time of synthesis of the polycarbodiimide compound, wherein the (meth) acrylic polymer, by changing the charging ratio of the other organic compounds to be added as needed, R ¹ and in Formula (1) in R ^2, it is possible to change the ratio of each residue.
In the polycarbodiimide compound represented by the formula (1-2) in the first embodiment, the carbonyl group (1720 cm) with respect to the peak intensity ratio of the ^{carbodiimide group (2112 cm-1) measured by infrared absorption (IR) spectrum measurement. The peak intensity ratio of -1} ) is preferably 0.2 to 8.
In the first embodiment, R ¹ and R ² of the formula (1-2) are as follows depending on the type of the organic compound forming them.
When the functional group having reactivity with the isocyanate group of the (meth) acrylic polymer is a hydroxyl group, the residue obtained by removing one hydroxyl group of the (meth) acrylic polymer,
When the functional group having reactivity with the isocyanate group of the (meth) acrylic polymer is a carboxyl group, the residue after removing one carboxyl group of the (meth) acrylic polymer is shown.
When the organic compound having at least one functional group reactive with the isocyanate group is a compound other than the above (meth) acrylic polymer, the residue excluding the functional group is shown.

In the first embodiment, ^{as the diisocyanate compound forming R 3} , the compound mentioned in the above <diisocyanate compound> can be used.
In the first embodiment, X ¹ and X ² are bonds formed by the reaction of the functional group of the organic compound with the isocyanate group of the diisocyanate compound, respectively, as described above. It is any group represented by the formulas (6) to (8) depending on the type of the compound forming ^{R 1} and R ^2. That is, when the functional group is a hydroxyl group, it is a urethane bond, when the functional group is a carboxyl group, it is an amide bond, and when the functional group is an amino group, it is a urea bond.
In the first embodiment, m is more preferably 2 to 20.

<Second embodiment>
The second embodiment of the present invention has at least one functional group having reactivity with an isocyanate group as an organic compound having a functional group having reactivity with an isocyanate group in the above formula (1-2). In addition to the (meth) acrylic polymer, one or more compounds selected from the group consisting of the compounds represented by the above formulas (2), (3), (4) and (5) as other organic compounds. It is an aspect including.
As the (meth) acrylic polymer having at least one functional group having reactivity with the isocyanate group, those described above can be used. The functional group of the (meth) acrylic polymer is preferably a hydroxyl group or a carboxyl group.
In the second embodiment, R ¹ and R ² of the formula (1-2) are as follows, depending on the type of the compound forming them.
When the functional group having reactivity with the isocyanate group of the (meth) acrylic polymer is a hydroxyl group, the residue obtained by removing one hydroxyl group of the (meth) acrylic polymer,
When the functional group having reactivity with the isocyanate group of the (meth) acrylic polymer is a carboxyl group, the residue obtained by removing one carboxyl group of the (meth) acrylic polymer,
When the compound represented by the above formula (3) is used, the residue obtained by removing one hydroxyl group from each structure,
When the compound represented by the above formula (4) is used, the residue excluding the amino group,
When the compound represented by the above formula (2) or the formula (5) is used, when Z ¹ and Z ² are hydroxyl groups, the residues excluding the hydroxyl groups, Z ¹ and Z ^2, are amino groups, respectively. If, it indicates the residue excluding the amino group.
In the second embodiment, the charging ratio of the (meth) acrylic polymer and one or more compounds selected from the group consisting of the formulas (2) to (5) at the time of synthesizing the polycarbodiimide compound is changed. Therefore, the ratio of each residue ^{in R 1} and R ² in the formula (1) can be changed.
In the polycarbodiimide compound represented by the formula (1-2) in the second embodiment, the carbonyl group (1720 cm) with respect to the peak intensity ratio of the ^{carbodiimide group (2112 cm-1) measured by infrared absorption (IR) spectrum measurement. The peak intensity ratio of -1} ) is preferably 0.2 to 8.

In a second embodiment, as the diisocyanate compound to form the R ^3, it is possible to use a compound listed above <diisocyanate compound>.
In the second embodiment, X ¹ and X ² are bonds formed by the reaction of the functional group of the organic compound with the isocyanate group of the diisocyanate compound, respectively, as described above. It is any group represented by the formulas (6) to (8) depending on the type of the compound forming ^{R 1} and R ^2. That is, when the functional group is a hydroxyl group, it is a urethane bond, when the functional group is a carboxyl group, it is an amide bond, and when the functional group is an amino group, it is a urea bond.
In the second embodiment, m is more preferably 2 to 20.

<Third embodiment>
A third embodiment of the present invention is in the above formula (1).
R ¹ and R ² are residues obtained by removing one of the functional groups from an organic compound having at least one functional group having reactivity with an isocyanate group, respectively.
R ³ is a divalent residue obtained by removing two isocyanate groups from the diisocyanate compound, and the diisocyanate compound contains an aliphatic hydrocarbon group or an alicyclic hydrocarbon group that directly bonds with the two isocyanate groups. a plurality of ^{R 3,} equal to or different from each other,
R ⁴ is a residue obtained by removing the functional group from the (meth) acrylic polymer having two functional groups reactive with the isocyanate group.
X ¹ and X ² are bonds formed independently by the reaction of the functional group of the organic compound with the isocyanate group of the diisocyanate compound.
X ³ is a bond formed by the reaction of the functional group of the (meth) acrylic polymer having two functional groups having reactivity with the isocyanate group independently and the isocyanate group of the diisocyanate compound. ,
m and n represent numbers from 1 to 20, respectively.
p represents a number from 1 to 20
The organic compound having at least one functional group having reactivity with the isocyanate group is selected from the group consisting of the compounds represented by the above formulas (2), (3), (4) and (5) 1 It is a polycarbodiimide compound which is a compound of more than one species.

In the third embodiment of the present invention, R ¹ and R ² are independently selected from the group consisting of the compounds represented by the above formulas (2), (3), (4) and (5), respectively. Residues derived from one or more compounds.
In a third embodiment of the present invention, as a diisocyanate compound to form the R ^3, it is possible to use a compound listed above <diisocyanate compound>.
In a third embodiment of the present invention, the organic compound forming the R ⁴ have two functional groups reactive with the isocyanate group-containing (meth) acrylic polymer. As such a (meth) acrylic polymer, the one described in the above <(meth) acrylic polymer having a functional group having reactivity with an isocyanate group> can be used. The functional group of the (meth) acrylic polymer is preferably a hydroxyl group or a carboxyl group.
In the polycarbodiimide compound represented by the formula (1) in the third embodiment of the present invention, the carbonyl group with respect to the peak intensity ratio of the ^{carbodiimide group (2112 cm-1) measured by infrared absorption (IR) spectrum measurement.} The peak intensity ratio of (1720 cm ^-1 ) is preferably 0.2 to 8.
In the third embodiment of the present invention, X ¹ and X ² are independently selected from the group consisting of the above formulas (2), (3), (4) and (5), respectively. It is a bond formed by a reaction between a functional group derived from a compound of more than one species and an isocyanate group of the isocyanate compound.
In a third embodiment of the present invention, X ³ are each independently, and the functional group having two functional groups reactive with the isocyanate group-containing (meth) acrylic polymer, an isocyanate group of the diisocyanate compound It is a bond formed by the reaction with the above, a urethane bond when the functional group is a hydroxyl group, and an amide bond when the functional group is a carboxyl group.

<Fourth Embodiment>
A fourth embodiment of the present invention is based on the above formula (1).
R ¹ and R ² are residues obtained by removing the functional group from the (meth) acrylic polymer having at least one functional group reactive with the isocyanate group, respectively.
R ³ is a divalent residue obtained by removing two isocyanate groups from the diisocyanate compound, and the diisocyanate compound contains an aliphatic hydrocarbon group or an alicyclic hydrocarbon group that directly bonds with the two isocyanate groups. a plurality of ^{R 3,} equal to or different from each other,
R ⁴ is a residue obtained by removing the functional group from the (meth) acrylic polymer having two functional groups reactive with the isocyanate group.
X ¹ and X ² are each independently formed by the reaction of the functional group of the (meth) acrylic polymer having at least one functional group having reactivity with the isocyanate group with the isocyanate group of the diisocyanate compound. Is a combination
X ³ is a bond formed by the reaction of the functional group of the (meth) acrylic polymer having two functional groups having reactivity with the isocyanate group independently and the isocyanate group of the diisocyanate compound. ,
m and n represent numbers from 1 to 20, respectively.
p is a polycarbodiimide compound representing a number from 1 to 20.

In the fourth embodiment of the present invention, the ^{organic compound forming R 1} and R ² is a (meth) acrylic polymer having at least one functional group having reactivity with an isocyanate group. As the (meth) acrylic polymer, the one described in the above <(meth) acrylic polymer having a functional group having reactivity with an isocyanate group> can be used. The functional group of the (meth) acrylic polymer is preferably a hydroxyl group or a carboxyl group.
In a fourth embodiment of the present invention, as a diisocyanate compound to form the R ^3, it is possible to use a compound listed above <diisocyanate compound>.
In the fourth embodiment of the present invention, the ^{organic compound forming R 4} is a (meth) acrylic polymer having two functional groups having reactivity with an isocyanate group. The functional group of the (meth) acrylic polymer is preferably a hydroxyl group or a carboxyl group. As such a (meth) acrylic polymer, the one described in the above <(meth) acrylic polymer having a functional group having reactivity with an isocyanate group> can be used.
In the fourth embodiment of the present invention, X ¹ and X ² are groups derived from a (meth) acrylic polymer having at least one functional group reactive with an isocyanate group, respectively. When the functional group is a hydroxyl group, it is a urethane bond, and when the functional group is a carboxyl group, it is an amide bond.
In a fourth embodiment of the present invention, X ³ includes: the functional group having two functional groups reactive with the isocyanate group-containing (meth) acrylic polymer, by reaction with the isocyanate groups of said diisocyanate compound It is a bond to be formed, and when the functional group is a hydroxyl group, it is a urethane bond, and when the functional group is a carboxyl group, it is an amide bond.
In the polycarbodiimide compound represented by the formula (1) in the fourth embodiment of the present invention, the carbonyl group with respect to the peak intensity ratio of the ^{carbodiimide group (2112 cm-1) measured by infrared absorption (IR) spectrum measurement.} The peak intensity ratio of (1720 cm ^-1 ) is preferably 0.2 to 8.

<Fifth Embodiment of the present invention>
A fifth embodiment of the present invention is in the above formula (1).
R ¹ and R ² are residues obtained by removing the functional group from an organic compound having at least one functional group reactive with an isocyanate group, respectively, and the organic compound is a reaction with an isocyanate group. Contains a (meth) acrylic polymer having at least one functional group
R ³ is a divalent residue obtained by removing two isocyanate groups from the diisocyanate compound, and the diisocyanate compound contains an aliphatic hydrocarbon group or an alicyclic hydrocarbon group that directly bonds with the two isocyanate groups. a plurality of ^{R 3,} equal to or different from each other,
R ⁴ is a functional group obtained by removing the functional group from a divalent organic compound having two functional groups reactive with an isocyanate group, and the divalent organic compound is a glycol compound or a dicarboxylic acid compound. Yes,
X ¹ and X ² are each independently formed by the reaction of the functional group of the (meth) acrylic polymer having at least one functional group having reactivity with the isocyanate group with the isocyanate group of the diisocyanate compound. Is a combination
X ³ is a urethane bond or an amide bond,
m and n represent numbers from 1 to 20, respectively.
p is a polycarbodiimide compound representing a number from 1 to 20.

In a fifth embodiment of the present invention, the ^{organic compound forming R 1} and R ² comprises a (meth) acrylic polymer having at least one functional group reactive with an isocyanate group. As the (meth) acrylic polymer, the one described in the above <(meth) acrylic polymer having a functional group having reactivity with an isocyanate group> can be used. The functional group of the (meth) acrylic polymer is preferably a hydroxyl group or a carboxyl group. As the organic compound other than the (meth) acrylic polymer, one or more of the compounds represented by the above formulas (2) to (5) can be used.
In the polycarbodiimide compound represented by the formula (1) in the fifth embodiment of the present invention, the carbonyl group with respect to the peak intensity ratio of the ^{carbodiimide group (2112 cm-1) measured by infrared absorption (IR) spectrum measurement.} The peak intensity ratio of (1720 cm ^-1 ) is preferably 0.2 to 8.
In a fifth embodiment of the present invention, as a diisocyanate compound to form the R ^3, it is possible to use a compound listed above <diisocyanate compound>.
In the fifth embodiment of the present invention, the ^{organic compound forming R 4} is an organic compound having two functional groups reactive with an isocyanate group, and the organic compound is a glycol compound or a dicarboxylic acid compound. ..
When the organic compound having two functional groups reactive with the isocyanate group is a glycol compound, the glycol compound is ethylene glycol, propylene glycol, 1,4-butanediol, diethylene glycol, dipropylene glycol, triethylene. It is preferably one or more selected from the group consisting of glycol, tripropylene glycol, polyethylene glycol, and polypropylene glycol, and preferably from the group consisting of ethylene glycol, 1,4-butanediol, diethylene glycol, triethylene glycol, and polyethylene glycol. More preferably, it is one or more selected.
The weight average molecular weight (Mw) of polyethylene glycol and polypropylene glycol is preferably 2,000 or less from the viewpoint of facilitating dissolution or dispersion in water or a hydrophilic solvent.
When the organic compound having two functional groups reactive with the isocyanate group is a dicarboxylic acid compound, the dicarboxylic acid compound is malonic acid, succinic acid, glutaric acid, adipic acid, pimeric acid, suberic acid and azeline. Examples thereof include one or more aromatic dicarboxylic acids selected from the group consisting of one or more saturated dicarboxylic acids selected from the group consisting of acids, phthalic acids, isophthalic acids and terephthalic acids.
In the fifth embodiment of the present invention, X ¹ and X ² are groups derived from an organic compound having at least one functional group having a reactivity with an isocyanate group, and the functional group is a hydroxyl group. If the functional group is a carboxyl group, it is an amide bond, and if the functional group is an amino group, it is a urea bond.
In a fifth embodiment of the present invention bond, X ³ is formed by the reaction of said functional group of the organic compound having two functional groups reactive with isocyanate groups, the isocyanate groups of said diisocyanate compound When the organic compound is a glycol compound, it is a urethane bond, and when the organic compound is a dicarboxylic acid compound, it is an amide bond.

<Aqueous resin cross-linking agent>
The aqueous resin cross-linking agent of the present invention contains the above polycarbodiimide compound.
In addition to the above polycarbodiimide compound, it is preferable to include an aqueous medium in consideration of subsequent use.
The aqueous resin cross-linking agent of the present invention can be produced by mixing the above-mentioned polycarbodiimide compound with an aqueous medium, if necessary.

In the aqueous resin cross-linking agent of the present invention, the content of polycarbodiimide is preferably 5 to 220 parts by mass, more preferably 5 to 150 parts by mass, still more preferably 5 to 90 parts by mass with respect to 100 parts by mass of the aqueous medium. 10 to 80 parts by mass is even more preferable, and 15 to 75 parts by mass is particularly preferable.
The solid content of the aqueous resin cross-linking agent of the present invention is preferably 5 to 65 parts by mass, more preferably 10 to 60 parts by mass, and even more preferably 20 to 55 parts by mass with respect to 100 parts by mass of the aqueous resin cross-linking agent. , 30 to 50 parts by mass is particularly preferable.

<Aqueous medium>
Examples of the aqueous medium that can be used for the aqueous resin cross-linking agent of the present invention include water and a mixed solvent of water and other solvents. The other solvent is not particularly limited as long as it is compatible with water, and examples thereof include alcohols, ethers, ketones, and esters.
Examples of alcohols include methyl alcohol, n-butyl alcohol, isopropyl alcohol, 2-ethylhexyl alcohol, ethylene glycol, propylene glycol, 2- (2-n-butoxyethoxy) ethanol and the like.
Examples of ethers include ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monohexyl ether, propylene glycol monoethyl ether, 3-methyl-3-methoxybutanol, diethylene glycol monoethyl ether, and diethylene glycol monobutyl ether. ..
Examples of the ketones include methyl isobutyl ketone, cyclohexanone, isophorone, acetylacetone and the like.
Examples of the esters include ethylene glycol monoethyl ether acetate and ethylene glycol monobutyl ether acetate.
These may be used alone or in combination of two or more.
As the aqueous medium, it is preferable from the environmental point of view that it is a completely aqueous system consisting of only water.

<Surfactant>
The aqueous resin cross-linking agent of the present invention uses a surfactant for the purpose of further improving the storage stability of the polycarbodiimide compound in an aqueous medium and the storage stability when coexisting with the aqueous resin. be able to.
Examples of the surfactant include nonionic surfactants, anionic surfactants, cationic surfactants, etc., and the storage stability of the carbodiimide-based aqueous resin cross-linking agent in the state of coexisting with the aqueous resin can be obtained. From the viewpoint of improvement, nonionic surfactants and anionic surfactants are preferable, and anionic surfactants are more preferable.
Specific examples of the anionic surfactant include sodium dodecylbenzenesulfonate, sodium dodecylsulfate, sodium lauryl ether sulfate, dipotassium alkenylsuccinate and the like, with sodium dodecylbenzenesulfonate being preferred.

When a surfactant is used, the amount used is preferably 0.1 part by mass or more, more preferably 0.3 part by mass or more, and preferably 5 parts by mass with respect to 100 parts by mass of the polycarbodiimide compound. Parts or less, more preferably 4 parts by mass or less. When the amount of the surfactant used is within the above range, the storage stability can be improved while suppressing the production cost.

<Aqueous resin composition>
The aqueous resin composition of the present invention contains the aqueous resin cross-linking agent and the aqueous resin of the present invention. Since the aqueous resin composition of the present invention contains the aqueous resin cross-linking agent of the present invention, a coating film having excellent solvent resistance can be produced by using the aqueous resin composition of the present invention.

<Aqueous resin>
The aqueous resin used in the present invention is a carboxyl group-containing resin, and is not particularly limited as long as it has a carboxyl group. For example, water-based urethane resin, acrylic resin, polyester resin, rubber-based latex resin and the like can be mentioned, and these resins can be preferably used. These resins may be used alone or in combination of two or more.

As the aqueous urethane resin, for example, polyols, carboxyl group-containing polyols, and carboxyl group-containing urethane-based prepolymers obtained from polyisocyanate compounds are used as a neutralizing agent and a chain extender in the presence of an organic solvent or water. Examples thereof include a resin obtained by reacting and then removing the solvent under reduced pressure.

Examples of the polyols that are the raw materials of the aqueous urethane resin include polymers or copolymers of low molecular weight polyols, and specifically, polyether polyols, polyester polyols, polycarbonate polyols, polyether ester polyols, and polycarbonate ester polyols. , Polycarbonate ether polyol and the like. These may be used alone or in combination of two or more.

The carboxyl group-containing polyols that are the raw materials of the aqueous urethane resin are compounds containing two or more hydroxyl groups and one or more carboxyl groups in one molecule, and have two hydroxyl groups and one carboxy in one molecule. Those containing a compound having a group are preferable.
Examples of the carboxyl group-containing polyols include dimethylolalkanoic acid such as 2,2-dimethylolpropionic acid and 2,2-dimethylolbutanoic acid, N, N-bishydroxyethylglycine, and N, N-bishydroxy. Ethylalanine, 3,4-dihydroxybutanesulfonic acid, 3,6-dihydroxy-2-toluenesulfonic acid and the like can be mentioned. Among them, dimethylol alkanoic acid is preferable, and 2,2-dimethylol propionic acid is more preferable from the viewpoint of easy availability. These may be used alone or in combination of two or more.

Further, as the raw material of the aqueous urethane resin, other polyols can be used, if necessary, in addition to the polyols and the carboxyl group-containing polyols. As the other polyols, any one other than the above-mentioned polyols and the polyols exemplified in the carboxyl group-containing polyols can be used without particular limitation.

The polyisocyanate compound which is the raw material of the aqueous urethane resin is not particularly limited, but specifically, 1,3-phenylenediocyanate, 1,4-phenylenediocyanate, 2,4-tolylene diisocyanate (TDI), 2 , 6-Tolylene diisocyanate, 4,4'-diphenylene methanediisocyanate (MDI), 2,4-diphenylmethane diisocyanate, 4,4'-diisocyanatobiphenyl, 3,3'-dimethyl-4,4'-di Isocyanatobiphenyl, 3,3'-dimethyl-4,4'-diisocyanatodiphenylmethane, 1,5-naphthylene diisocyanate, 4,4', 4 "-triphenylmethane triisocyanate, m-isocyanatophenylsulfonyl Aromatic polyisocyanate compounds such as isocyanate and p-isocyanatophenylsulfonyl isocyanate; ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), dodecamethylene diisocyanate, 1,6,11-undecantryisocyanate, 2,2,4 -Trimethylhexamethylene diisocyanate, lysocyanate diisocyanate, 2,6-diisocyanatomethyl caproate, bis (2-isocyanatoethyl) fumarate, bis (2-isocyanatoethyl) carbonate, 2-isocyanatoethyl-2,6- Alibo polyisocyanate compounds such as diisocyanatohexanoate; isophorone diisocyanate (IPDI), 4,4'-dicyclohexylmethane diisocyanate (hydrogenated MDI), cyclohexylene diisocyanate, methylcyclohexylene diisocyanate (hydrogenated TDI), bis ( Examples thereof include alicyclic polyisocyanate compounds such as 2-isocyanatoethyl) -4-diclohexene-1,2-dicarboxylate, 2,5-norbornandiisocyanate, and 2,6-norbornandiisocyanate. These polyisocyanate compounds may be used alone or in combination of two or more.

The number of isocyanate groups per molecule of the polyisocyanate compound is usually two, but polyisocyanates having three or more isocyanate groups such as triphenylmethane triisocyanate can also be used as long as the polyurethane resin in the present invention does not gel. Can be used.
Among the above polyisocyanate compounds, 4,4'-diphenylene methane diisocyanate (MDI), isophorone diisocyanate (IPDI), 4,4'-dicyclohexylmethane diisocyanate (hydrogenated MDI) from the viewpoint of controlling reactivity and imparting strength. ) Is preferable.

Examples of the neutralizing agent include trimethylamine, triethylamine, triisopropylamine, tributylamine, triethanolamine, N-methyldiethanolamine, N-phenyldiethanolamine, dimethylethanolamine, diethylethanolamine, N-methylmorpholine, pyridine, and 2 -(Dimethylamino) -2-methyl-1-propanol and other organic amines; ammonia and the like. Among the above, organic amines are preferable, tertiary amines are more preferable, and triethylamine and 2- (dimethylamino) -2-methyl-1-propanol are particularly preferable.

Examples of the chain extender include compounds having a reactivity with an isocyanate group, and specific examples thereof include ethylenediamine, 1,4-tetramethylenediamine, 2-methyl-1,5-pentanediamine, and 1,4. -Butanediamine, 1,6-hexamethylenediamine, 1,4-hexamethylenediamine, 3-aminomethyl-3,5,5-trimethylcyclohexylamine, 1,3-bis (aminomethyl) cyclohexane, xylylenediamine, Amine compounds such as piperazine, adipoil hydrazide, hydrazine, 2,5-dimethylpiperazine, diethylenetriamine, triethylenetetramine, diol compounds such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, etc. Examples thereof include polyalkylene glycols typified by polyethylene glycol and water. Of these, amine compounds are preferable, and ethylenediamine is more preferable. These may be used alone or in combination of two or more.

Examples of the acrylic resin include polymerizable unsaturated carboxylic acid or an anhydride thereof, acrylic monomers other than (meth) acrylic acid esters and (meth) acrylic acid, and if necessary, α-methylstyrene and vinyl acetate. Examples thereof include an acrylic resin obtained by copolymerizing the above with a polymerization method such as emulsion polymerization, solution polymerization, or massive polymerization.
Specific examples of polymerizable unsaturated carboxylic acids and their anhydrides include (meth) acrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid and their anhydrides.
Examples of (meth) acrylic acid esters include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and 2-hydroxy (meth) acrylate. Examples include ethyl.
Examples of acrylic monomers other than (meth) acrylic acid include (meth) acrylamide and (meth) acrylonitrile.

Examples of the polyester resin include a polyester resin obtained by extending a chain of a polyester glycol having a hydroxyl group at the terminal and a tetracarboxylic dianhydride by an esterification reaction.

Examples of the rubber-based latex resin include a natural rubber-based latex resin having a carboxyl group and a synthetic rubber-based latex resin having a carboxyl group.

The aqueous resin varies depending on its type and molecular weight, but generally has a resin solid acid value based on a carboxyl group of 5 to 60 mgKOH / g, preferably 10 to 55 mgKOH / g.

In a preferred embodiment of the present invention, the molar ratio of the carbodiimide group contained in the aqueous resin composition to the carboxyl group contained in the aqueous resin composition is usually 0.1 to 1.2, preferably 0.2. The content of the polycarbodiimide compound and the aqueous resin is adjusted so as to be ~ 1.0.

[Method for producing polycarbodiimide compound]
The method for producing a polycarbodiimide compound according to an embodiment of the present invention is
Step (A): A step of carbodiimidizing a diisocyanate compound in the presence of a catalyst to obtain a polycarbodiimide precursor having isocyanate groups at both ends.
Step (B): The (meth) acrylic polymer having at least one functional group capable of reacting with an isocyanate group has a residue obtained by removing the functional group and / or having two functional groups capable of reacting with an isocyanate group (meth). ) The production method comprising a reaction step for introducing a residue obtained by removing the functional group from the acrylic polymer into the polycarbodiimide precursor.

[Step (A)]
In step (A), the diisocyanate compound is subjected to a carbodiimideization reaction in the presence of a catalyst to obtain a polycarbodiimide precursor having isocyanate groups at both ends.
As the diisocyanate compound, the compounds listed in the section <Diisocyanate compound> can be used.
Examples of the catalyst used in the carbodiimidization reaction include 1-phenyl-2-phospholene-1-oxide, 3-methyl-1-phenyl-2-phospholene-1-oxide, and 1-ethyl-2-phospholene-1-. Examples thereof include oxides, 3-methyl-2-phospholene-1-oxides, and phosphorene oxides such as these 3-phosphoren isomers. Among these, 3-methyl-1-phenyl is used from the viewpoint of reactivity. -2-Phenyl-1-oxide is preferred.
The amount of the catalyst used in the method for producing a polycarbodiimide compound is usually 0.01 to 2.0 parts by mass with respect to 100 parts by mass of the diisocyanate compound used for carbodiimide formation.

The carbodiimidization reaction can be carried out without a solvent or in a solvent. Solvents that can be used include alicyclic ethers such as tetrahydroxyfuran, 1,3-dioxane, and dioxolane: benzene, toluene, xylene, and aromatic hydrocarbons such as ethylbenzene: chlorobenzene, dichlorobenzene, trichlorobenzene, percrene, and the like. Examples thereof include halogenated hydrocarbons such as trichloroethane and dichloroethane, and cyclohexanone. These may be used alone or in combination of two or more.
When the reaction is carried out in a solvent, the concentration of the diisocyanate compound is preferably 5 to 55% by mass, more preferably 5 to 20% by mass.

The conditions of the carbodiimidization reaction are not particularly limited, but are preferably 40 to 250 ° C., more preferably 80 to 195 ° C., preferably 1 to 30 hours, and more preferably 5 to 25 hours. When the reaction is carried out in a solvent, the temperature is preferably from 40 ° C. to the boiling point of the solvent.

The degree of polymerization of the polycarbodiimide precursor is not particularly limited, but is preferably 1 to 10, more preferably 1 to 5 from the viewpoint of facilitating dissolution or dispersion of the polycarbodiimide compound in water or a hydrophilic solvent.

[Step (B)]
In step (B), the (meth) acrylic polymer having at least one functional group capable of reacting with an isocyanate group has a residue obtained by removing the functional group and / or having two functional groups capable of reacting with an isocyanate group ((meth). The reaction for introducing the residue obtained by removing the functional group from the meta) acrylic polymer into the polycarbodiimide precursor is carried out.
Here, in the step (B), a (meth) acrylic polymer having at least one functional group having reactivity with an isocyanate group or a (meth) acrylic weight having two functional groups having reactivity with an isocyanate group. Be sure to use coalescence.
The reaction method in step (B) is not particularly limited, and for example,
(I) The above polycarbodiimide precursor is reacted with an organic compound having at least one functional group capable of reacting with an isocyanate group constituting the terminal of the polycarbodiimide (step (B1)), and if necessary, obtained. The compound is reacted with a (meth) acrylic polymer having at least one functional group capable of reacting with an isocyanate group (step (B2)) method (ii). The constituent organic compound having at least one functional group capable of reacting with the isocyanate group is reacted (step (B3)), and the obtained compound and the organic compound having two functional groups capable of reacting with the above-mentioned isocyanate group are reacted. (Step (B4)) Method (iii) The polycarbodiimide precursor, the first organic compound having at least one functional group capable of reacting with the isocyanate group, and A second organic compound having two functional groups capable of reacting with an isocyanate group is simultaneously reacted (step (B5)), and the obtained compound and a second functional group having at least one functional group capable of reacting with the isocyanate group are further reacted. Reaction with an organic compound (step (B6)) Method (iv) The polycarbodiimide precursor is reacted with an organic compound having two functional groups capable of reacting with the isocyanate group (step (B7)). Examples thereof include a method of reacting the obtained compound with an organic compound having at least one functional group capable of reacting with the isocyanate group (step (B8)).
Above all, the method according to (i), (ii), and (iii) is preferable from the viewpoint of controlling the local reaction and the increase in molecular weight.

In the method according to (i), a (meth) acrylic polymer having at least one functional group capable of reacting with an isocyanate group is used in at least one of the step (B1) and the step (B2).
In the method according to (ii), at least a (meth) acrylic polymer having at least one functional group capable of reacting with an isocyanate group is used in the step (B3), or a functional group capable of reacting with an isocyanate group in the step (B4). At least a (meth) acrylic polymer having two groups may be used, or both.
In the method according to (iii), at least one of the first organic compound and the second organic compound used in step (B5) or step (B6) has at least one functional group capable of reacting with an isocyanate group (meth). A (meth) acrylic polymer containing an acrylic polymer and having two functional groups capable of reacting with an isocyanate group in the step (B5) may be used, or both may be used. The first organic compound and the second organic compound may be the same or different.
In the method according to (iv), a (meth) acrylic polymer having two functional groups capable of reacting with an isocyanate group in step (B7) is used, or at least one functional group capable of reacting with an isocyanate group in step (B8) is used. (Meta) acrylic polymer having one may be used, or both may be used.

In the above methods (i) to (iv), the organic compound having at least one functional group capable of reacting with the isocyanate group is [a (meth) acrylic polymer having a functional group reactive with the isocyanate group. ], A (meth) acrylic polymer having at least one functional group reactive with the isocyanate group mentioned in the above section, a compound represented by the above formulas (2), (3), (4) and (5). Can be mentioned.
Further, as the organic compound having two functional groups capable of reacting with the above-mentioned isocyanate group, the reaction with the isocyanate group mentioned in the section of [(meth) acrylic polymer having a functional group having reactivity with the isocyanate group]. Examples thereof include a (meth) acrylic polymer having two functional groups having a property, a glycol compound and a dicarboxylic acid compound mentioned in the above section <Fifth Embodiment>.
In steps (B1), (B3), (B5) and (B7), for example, 0.1 to 0.9 equivalents with respect to the total amount of isocyanate groups possessed by the polycarbodiimide precursor obtained in step (A) at both ends. It is preferable to adjust the amount of raw materials used for the organic compound having at least one functional group capable of reacting with the isocyanate group and / or the organic compound having two functional groups capable of reacting with the isocyanate group. ..
The amount of the organic compound having at least one functional group capable of reacting with the isocyanate group and / or the organic compound having two functional groups capable of reacting with the isocyanate group depends on the isocyanates that the polycarbodiimide precursor has at both ends. With respect to the total functional group equivalent, one preferred embodiment is 0.2 to 0.9 equivalent, and another preferred embodiment is 0.25 to 0.85 equivalent. Within these ranges, a polycarbodiimide compound used for forming a coating film having excellent solvent resistance can be obtained.

The reaction conditions of the above steps (B1), (B3), (B5), and (B7) are not particularly limited, but are preferably 50 to 200 ° C., more preferably 100 to 180 ° C., and then the organic. It is preferable to add the compound and further carry out the reaction at about 80 to 200 ° C. for about 0.5 to 5 hours.

Reactivity with the organic compound having at least one functional group having reactivity with the isocyanate group and / or the isocyanate group in the step (B2), the step (B4), the step (B6), and the step (B8). The amount of the organic compound having two functional groups having two functional groups is 0.1 as a preferred embodiment with respect to the functional group equivalent of the total amount of isocyanate groups possessed by the polycarbodiimide precursor obtained in the step (A) at both ends. ~ 0.8 equivalents, another preferred embodiment is 0.15 to 0.75 equivalents. Within these ranges, a polycarbodiimide compound used for forming a coating film having excellent solvent resistance can be obtained.
The reaction conditions of the above steps (B2), step (B4), step (B6), and step (B8) are not particularly limited, but the reaction temperature is preferably about 80 to 200 ° C., and the reaction time is 0.5. It is preferably about 5 hours.
In any of the above methods (i) to (iii), a (meth) acrylic polymer having at least one functional group capable of reacting with an isocyanate group and / or a functional group capable of reacting with an isocyanate group is used. When two (meth) acrylic polymers are used, it is preferable to set up the steps so that the reaction between the functional group and the isocyanate group of these (meth) acrylic polymers is the final reaction. Further, the reaction temperature at this time is preferably a relatively low temperature such as 60 to 120 ° C. When these conditions are satisfied, the dispersibility of the produced polycarbodiimide compound in a solvent is improved.

The chain extension unit p of the polycarbodiimide compound of the formula (1) is not particularly limited, but is preferably 0 to 5, from the viewpoint of facilitating dissolution or dispersion of the polycarbodiimide compound in water or a hydrophilic solvent. It is preferably 0 to 2. When the step (B2) is not included in the method (i) above, p becomes 0.

Hereinafter, the present invention will be specifically described with reference to Examples. However, the present invention is not limited to the following embodiments.

[Synthesis of polycarbodiimide]
Polycarbodiimides used in Examples and Comparative Examples were synthesized according to the following procedure.
<Synthesis example 1>
1000 parts by mass of dicyclohexylmethane-4,4'-diisocyanate and 5 parts by mass of carbodiimidization catalyst (3-methyl-1-phenyl-2-phospholene-1-oxide) were placed in a reaction vessel equipped with a reflux tube and a stirrer. After stirring at 180 ° C. for 17 hours under a nitrogen stream, the mixture was taken out on a Teflon sheet to obtain an isocyanate-terminated dicyclohexylmethane polycarbodiimide. As a result of measuring the NCO%, it was 9.93% (degree of polymerization = 2.68).

[Synthesis of polycarbodiimide (B1)]
<Synthesis example 2>
21.2 parts by mass of the polycarbodiimide resin obtained in Synthesis Example 1 was placed in a reaction vessel equipped with a reflux tube and a stirrer and heated to 150 ° C., and polyethylene glycol monomethyl ether (molecular weight 557, hereinafter also referred to as “MPEG550”). ) 13.9 parts by mass was added, and the mixture was reacted for 2 hours with heating and stirring at 150 ° C.
Next, the mixture was cooled to 100 ° C., and 15.0 parts by mass of an acrylic resin having a monovalent hydroxyl group (manufactured by Soken Kagaku, product name UMM-1001, hydroxyl value 600 g / eq) and 1,8-diazabicyclo (5.4. 0) -Undecene-7 (hereinafter, also referred to as "DBU") in an amount of 0.11 part by mass was added, and the mixture was reacted for 1 hour with heating and stirring at 100 ° C.
After confirming that the absorption of the isocyanate group having a wavelength of 2200 to 2300 cm- ¹ has disappeared by infrared absorption (IR) spectrum measurement and cooling to 70 ° C., propylene glycol monomethyl ether (hereinafter, also referred to as "MFG") is used as a solvent. ) Was added in an amount of 62.8 parts by mass and 12.6 g of ion-exchanged water was added, and the mixture was stirred for 1 hour to dissolve the resin and cooled to room temperature.

[Synthesis of polycarbodiimide (B2)]
<Synthesis example 3>
1000 parts by mass of dicyclohexylmethane-4,4'-diisocyanate and 5 parts by mass of carbodiimidization catalyst (3-methyl-1-phenyl-2-phospholene-1-oxide) were placed in a reaction vessel equipped with a reflux tube and a stirrer. After stirring at 190 ° C. for 16 hours under a nitrogen stream, the mixture was taken out on a Teflon sheet to obtain a polycarbodiimide resin. As a result of measuring the NCO%, it was 6.11% (degree of polymerization = 5.10).
<Synthesis example 4>
27.3 parts by mass of the obtained polycarbodiimide resin was placed in a reaction vessel equipped with a reflux tube and a stirrer and heated to 150 ° C., 11.1 parts by mass of MPEG550 was added thereto, and the mixture was reacted for 2 hours while heating and stirring at 150 ° C. It was.
Next, the mixture was cooled to 100 ° C., 12.0 parts by mass of UMM-1001 and 0.10 parts by mass of DBU were added, and the mixture was reacted for 1 hour while heating and stirring at 100 ° C.
After confirming that the absorption of isocyanate groups had disappeared by IR measurement, the mixture was cooled to 70 ° C., 63.2 parts by mass of MFG was added as a solvent, 12.6 g of ion-exchanged water was added, and the mixture was stirred for 1 hour, and then brought to room temperature. Obtained by cooling.

[Synthesis of polycarbodiimide (B3)]
<Synthesis example 5>
21.0 parts by mass of the polycarbodiimide resin obtained in Synthesis Example 1 was placed in a reaction vessel equipped with a reflux tube and a stirrer and heated to 150 ° C., then cooled to 100 ° C., and UMM-1001 was added to 29.8 parts by mass. 0.11 part by mass of DBU was added, and the mixture was reacted for 1 hour with heating and stirring at 100 ° C.
After confirming that the absorption of the isocyanate group had disappeared by IR measurement and cooling to 70 ° C., 76.2 parts by mass of tripropylene glycol monomethyl ether (hereinafter, also referred to as “MFTG”) was added as a solvent for 1 hour. It was obtained by stirring and then cooling to room temperature.

[Synthesis of polycarbodiimide (B4)]
21.0 parts by mass of the polycarbodiimide resin obtained in Synthesis Example 1 was placed in a reflux tube and a reaction vessel equipped with a stirrer and heated to 150 ° C., 6.86 parts by mass of MPEG550 was added, and the mixture was heated and stirred at 150 ° C. for 2 hours. It was reacted.
Next, the mixture was cooled to 100 ° C., 22.2 parts by mass of UMM-1001 and 0.11 parts by mass of DBU were added, and the mixture was reacted for 1 hour with heating and stirring at 100 ° C.
After confirming that the absorption of the isocyanate group had disappeared by IR measurement, the mixture was cooled to 70 ° C., 75.3 parts by mass of MFTG was added as a solvent, and the mixture was stirred for 1 hour and then cooled to room temperature.

[Synthesis of polycarbodiimide (B5)]
27.3 parts by mass of the polycarbodiimide resin obtained in Synthesis Example 2 was placed in a reflux tube and a reaction vessel equipped with a stirrer and heated to 150 ° C., 5.58 parts by mass of MPEG550 was added, and the mixture was heated and stirred at 150 ° C. for 2 hours. It was reacted.
Next, the mixture was cooled to 100 ° C., 18.0 parts by mass of UMM-1001 and 0.11 parts by mass of DBU were added, and the mixture was reacted for 1 hour with heating and stirring at 100 ° C.
After confirming that the absorption of the isocyanate group had disappeared by IR measurement, the mixture was cooled to 70 ° C., 75.4 parts by mass of MFTG was added as a solvent, and the mixture was stirred for 1 hour and then cooled to room temperature.

[Synthesis of polycarbodiimide (B6)]
25.4 parts by mass of the polycarbodiimide resin obtained in Synthesis Example 1 was placed in a reflux tube and a reaction vessel equipped with a stirrer and heated to 150 ° C., 16.5 parts by mass of MPEG550 was added thereto, and the mixture was heated and stirred at 150 ° C. It was allowed to react for 2 hours.
Next, cool to 100 ° C., add 29.2 parts by mass of an acrylic resin having a divalent hydroxyl group (manufactured by Soken Kagaku, product name UT1001, hydroxyl value 970 g / eq) and 0.11 parts by mass of DBU, and at 100 ° C. The reaction was carried out for 1 hour with heating and stirring.
After confirming that the absorption of the isocyanate group had disappeared by IR measurement, the mixture was cooled to 70 ° C., and then the resin was dissolved by stirring 83.9 parts by mass of MFG as a solvent for 1 hour, and cooled to room temperature. ..

[Synthesis of polycarbodiimide (B7)]
25.0 parts by mass of the polycarbodiimide resin obtained in Synthesis Example 1 was placed in a reflux tube and a reaction vessel equipped with a stirrer and heated to 150 ° C., 8.2 parts by mass of MPEG550 was added, and the mixture was heated and stirred at 150 ° C. for 2 hours. It was reacted.
Next, the mixture was cooled to 100 ° C., 57.4 parts by mass of UT1001 and 0.11 parts by mass of DBU were added, and the mixture was reacted for 1 hour while heating and stirring at 100 ° C.
After confirming that the absorption of isocyanate groups has disappeared by IR measurement, the mixture is cooled to 70 ° C., 135.4 parts by mass of MFG is added as a solvent, and the mixture is stirred for 1 hour to dissolve the resin and cooled to room temperature. I got it.

[Synthesis of polycarbodiimide (B8)]
20.5 parts by mass of the polycarbodiimide resin obtained in Synthesis Example 1 was placed in a reaction vessel equipped with a reflux tube and a stirrer and heated to 150 ° C., and MPEG550 was added thereto by 6.7 parts by mass and propylene having a divalent hydroxyl group. 0.92 parts by mass of glycol was added, and the mixture was reacted for 2 hours with heating and stirring at 150 ° C.
Next, the mixture was cooled to 100 ° C., 7.29 parts by mass of UMM-1001 and 0.10 parts by mass of DBU were added, and the mixture was reacted for 1 hour with heating and stirring at 100 ° C.
After confirming that the absorption of the isocyanate group had disappeared by IR measurement, the mixture was cooled to 70 ° C., 53.1 parts by mass of propylene glycol monomethyl ether (hereinafter, also referred to as “MFDG”) was added as a solvent, and the mixture was stirred for 1 hour. It was obtained by dissolving the resin and cooling it to room temperature.

[Synthesis of polycarbodiimide (B9)]
21.0 parts by mass of the polycarbodiimide resin obtained in Synthesis Example 1 was placed in a reaction vessel equipped with a reflux tube and a stirrer and heated to 150 ° C., 27.8 parts by mass of MPEG550 and 0.11 parts by mass of DBU were added, and 150 parts were added. The reaction was carried out for 2 hours with heating and stirring at ° C.
After confirming that the absorption of the isocyanate group had disappeared by IR measurement and cooling to 70 ° C., add 61.0 parts by mass of MFG as a solvent and 12.2 g of ion-exchanged water and stir for 1 hour to prepare the resin. Obtained by melting and cooling to room temperature.

[Synthesis of polycarbodiimide (B10)]
20.0 parts by mass of the polycarbodiimide resin obtained in Synthesis Example 1 was placed in a reaction vessel equipped with a reflux tube and a stirrer and heated to 150 ° C., 16.3 parts by mass of MPEG550 and 0.11 parts by mass of DBU were added, and 150 parts were added. The reaction was carried out for 2 hours with heating and stirring at ° C.
After confirming that the absorption of the isocyanate group had disappeared by IR measurement and cooling to 70 ° C., add 45.4 parts by mass of MFG as a solvent and 9.08 g of ion-exchanged water and stir for 1 hour to prepare the resin. Obtained by melting and cooling to room temperature.

[Synthesis of polycarbodiimide (B11)]
In the synthesis example of polycarbodiimide (B6), instead of UT1001, polyethylene glycol having a divalent hydroxyl group (molecular weight 400) was used in an amount of 6.0 parts by mass, and MFDG was used as a solvent in an amount of 71.9 parts by mass. Obtained by doing.

[Synthesis of polycarbodiimide (B12)]
In the synthetic operation of polycarbodiimide (B8), instead of UT1001, 23.4 parts by mass of hydrogenated polybutadiene (GI-1000, molecular weight 1556) having a divalent hydroxyl group and 97.9 parts by mass of MFDG as a solvent were used. Others were obtained by performing the same operation.

[Synthesis of polycarbodiimide (B13)]
In the synthetic operation of polycarbodiimide (B8), instead of UT1001, a polyester polyol (RFK-505, molecular weight 456) having a divalent hydroxyl group was used in an amount of 6.85 parts by mass, and MFDG was used as a solvent in an amount of 73.1 parts by mass. Obtained a clear liquid by performing the same operation.

[Synthesis of polycarbodiimide (B14)]
<Synthesis example 6>
50 parts by mass of tetramethylxylylene diisocyanate, 32.0 parts by mass of MPEG550, and 34.5 parts by mass of UMM-1001 were placed in a reaction vessel equipped with a perfusion tube and a stirrer, and stirred at 60 ° C. for 2 hours under a nitrogen stream. After that, 2 parts by mass of a carbodiimidization catalyst (3-methyl-1-phenyl-2-phospholene-1-oxide) was added, and the mixture was reacted at 80 ° C. for 7 hours.
After confirming that the absorption of the isocyanate group had disappeared by IR measurement, 159.5 parts by mass of MFDG was added as a solvent, the resin was dissolved by stirring for 1 hour, and the resin was cooled to room temperature to theoretically have a degree of polymerization of 4. Carbodiimide was obtained.

Table 1 below summarizes the raw material preparation ratios for the synthesis of the above polycarbodiimides (B1) to (B14). In Table 1, the charging ratio is expressed as a molar ratio.

(Preparation of coating film sample)
The sample bottle was weighed at the weight ratio shown in Table 2, stirred with a stirrer and a magnetic stirrer for 1 hour, and then the immediately prepared aqueous resin composition was placed on an aluminum plate substrate using a bar coater. A coating film sample was obtained by coating with a thickness of about 60 μm and drying in a room at 25 ° C. for 1 day.
(Table 4 is heated in an oven at 120 ° C for 30 minutes instead of drying in a room at 25 ° C for 1 day)

[Solvent resistance evaluation of coating film]
A cotton impregnated with methyl ethyl ketone was placed on the obtained coating film sample, left to stand for 30 minutes with a lid covered, and then the cotton was removed and the damage to the coating film was evaluated on a 5-point scale.
(Under the conditions shown in Tables 3 and 4, 70% isopropyl alcohol was used instead of methyl ethyl ketone)

<Evaluation criteria>
5: No change 4: Slightly left behind 3: Discolored to white 2: Part of the coating film is melted and part of the aluminum base material is exposed 1: The coating film is melted and the entire aluminum base material is exposed

The coating film of the example using the aqueous resin cross-linking agent using the polycarbodiimide compound of the present invention having a structural unit derived from the (meth) acrylic polymer in the molecule does not have such a structural unit. It showed excellent solvent resistance as compared with the coating film of the comparative example using the compound. Moreover, even if the position of the structural unit derived from the (meth) acrylic polymer in the molecule is different, in other words, it is different whether it exists at the terminal or in the repeating unit in the molecule. Even if there is, a coating film having similarly excellent solvent resistance was obtained.
Further, from the results in Tables 2 to 4, even when different types of water-based resins (acrylic resin, water-based urethane resin, polyester resin) were used, a coating film having similarly excellent solvent resistance was obtained.
When the diisocyanate compound used for synthesizing the molecule of the polycarbodiimide compound was an aromatic diisocyanate (Comparative Example 6), the solvent resistance of the coating film was inferior.

According to the present invention, it is possible to provide an aqueous resin cross-linking agent used for forming a coating film having excellent solvent resistance, a polycarbodiimide compound that can be used as the aqueous resin cross-linking agent, and the like.

Claims (14)

1. A polycarbodiimide compound represented by the following formula (1).
   R ¹ -X ^1- (R ³ -N = C = N) _m -R ^3- [X ³ -R ⁴ -X ^3- (R ³ -N = C = N) _n -R ³ ] _p -X ² -R ² (1)
   In equation (1)
   R ¹ and R ² are residues obtained by removing one of the functional groups from an organic compound having at least one functional group having reactivity with an isocyanate group, respectively.
   R ³ is a divalent residue obtained by removing two isocyanate groups from the diisocyanate compound, and the diisocyanate compound contains an aliphatic hydrocarbon group or an alicyclic hydrocarbon group that directly bonds with the two isocyanate groups. a plurality of ^{R 3,} equal to or different from each other,
   R ⁴ is a residue obtained by removing the functional group a functional group having a reactivity of an organic compound having two isocyanate groups, a plurality of R ^4, equal to or different from each other,
   At ^{least one of R 1} , R ² and R ⁴ is a residue obtained by removing the functional group from a (meth) acrylic polymer having a functional group reactive with an isocyanate group.
   X ¹ , X ² and X ³ are bonds formed independently by the reaction of the functional group of the organic compound with the isocyanate group of the diisocyanate compound.
   m and n represent numbers from 1 to 20, respectively.
   p represents a number from 0 to 20.
2. The polycarbodiimide compound according to claim 1, which is represented by the following formula (1-2).
   R ¹ -X ^1- (R ³ -N = C = N) _m -R ³ -X ² -R ² (1-2)
   In equation (1-2)
   R ¹ and R ² are residues obtained by removing one of the functional groups from an organic compound having at least one functional group having reactivity with an isocyanate group, respectively.
   R ³ is a divalent residue obtained by removing two isocyanate groups from the diisocyanate compound, and the diisocyanate compound contains an aliphatic hydrocarbon group or an alicyclic hydrocarbon group that directly bonds with the two isocyanate groups. a plurality of ^{R 3,} equal to or different from each other,
   The organic compound having at least one functional group reactive with the isocyanate group comprises a (meth) acrylic polymer having at least one functional group reactive with the isocyanate group.
   X ¹ and X ² are bonds formed independently by the reaction of the functional group of the organic compound with the isocyanate group of the diisocyanate compound.
   m represents a number from 1 to 20.
3. The organic compound having at least one functional group having reactivity with the isocyanate group is further selected from the group consisting of the compounds represented by the following formulas (2), (3), (4) and (5). The polycarbodiimide compound according to claim 2, which comprises one or more compounds.
   R ^5- (O-CH _2- CHR ⁶ ) _p- Z ¹ (2)
   (In the formula, R ⁵ is an alkyl group having 1 to 4 carbon atoms, R ⁶ is a hydrogen atom or a methyl group, Z ¹ is OH or NH ₂ , and p is an integer of 4 to 30.)
   (R ⁷ ) ₂ N-R ^8- OH (3)
   (In the formula, R ⁷ is independently an alkyl group having 1 to 6 ^{carbon atoms, and R 8} is an alkylene group having 1 to 10 carbon atoms or a polyoxyalkylene group.)
   (R ⁹ ) ₂ N-R ^10- NH ₂ (4)
   (In the formula, R ⁹ is independently an alkyl group having 1 to 6 ^{carbon atoms, and R 10} is an alkylene group having 1 to 10 carbon atoms or a polyoxyalkylene group.)
   _{^{Z 2 -R 11 -SO 3 M (}} 5)
   (In the formula, R ¹¹ is an alkylene group having 1 to 10 carbon atoms, M is an alkali metal, and Z ² is OH or NH _2. )
4. The second aspect of claim 2, wherein the organic compound having at least one functional group having reactivity with an isocyanate group contains only a (meth) acrylic polymer having at least one functional group having reactivity with an isocyanate group. Polycarbodiimide compound.
5. In the above formula (1)
   R ¹ and R ² are residues obtained by removing one of the functional groups from an organic compound having at least one functional group having reactivity with an isocyanate group, respectively.
   R ³ is a divalent residue obtained by removing two isocyanate groups from the diisocyanate compound, and the diisocyanate compound contains an aliphatic hydrocarbon group or an alicyclic hydrocarbon group that directly bonds with the two isocyanate groups. a plurality of ^{R 3,} equal to or different from each other,
   R ⁴ is a residue obtained by removing the functional group from the (meth) acrylic polymer having two functional groups reactive with the isocyanate group.
   X ¹ and X ² are bonds formed independently by the reaction of the functional group of the organic compound with the isocyanate group of the diisocyanate compound.
   X ³ is a bond formed by the reaction of the functional group of the (meth) acrylic polymer having two functional groups having reactivity with the isocyanate group independently and the isocyanate group of the diisocyanate compound. ,
   m and n represent numbers from 1 to 20, respectively.
   p represents a number from 1 to 20
   The organic compound having a functional group having reactivity with the isocyanate group is one or more selected from the group consisting of the compounds represented by the following formulas (2), (3), (4) and (5). The polycarbodiimide compound according to claim 1, which is a compound.
   R ^5- (O-CH _2- CHR ⁶ ) _p- Z ¹ (2)
   (In the formula, R ⁵ is an alkyl group having 1 to 4 carbon atoms, R ⁶ is a hydrogen atom or a methyl group, Z ¹ is OH or NH ₂ , and p is an integer of 4 to 30.)
   (R ⁷ ) ₂ N-R ^8- OH (3)
   (In the formula, R ⁷ is independently an alkyl group having 1 to 6 ^{carbon atoms, and R 8} is an alkylene group having 1 to 10 carbon atoms or a polyoxyalkylene group.)
   (R ⁹ ) ₂ N-R ^10- NH ₂ (4)
   (In the formula, R ⁹ is independently an alkyl group having 1 to 6 ^{carbon atoms, and R 10} is an alkylene group having 1 to 10 carbon atoms or a polyoxyalkylene group.)
   _{^{Z 2 -R 11 -SO 3 M (}} 5)
   (In the formula, R ¹¹ is an alkylene group having 1 to 10 carbon atoms, M is an alkali metal, and Z ² is OH or NH _2. )
6. In the above formula (1)
   R ¹ and R ² are residues obtained by removing the functional group from the (meth) acrylic polymer having at least one functional group reactive with the isocyanate group, respectively.
   R ³ is a divalent residue obtained by removing two isocyanate groups from the diisocyanate compound, and the diisocyanate compound contains an aliphatic hydrocarbon group or an alicyclic hydrocarbon group that directly bonds with the two isocyanate groups. a plurality of ^{R 3,} equal to or different from each other,
   R ⁴ is a residue obtained by removing the functional group from the (meth) acrylic polymer having two functional groups reactive with the isocyanate group.
   X ¹ and X ² are each independently formed by the reaction of the functional group of the (meth) acrylic polymer having at least one functional group having reactivity with the isocyanate group with the isocyanate group of the diisocyanate compound. Is a combination
   X ³ is a bond formed by the reaction of the functional group of the (meth) acrylic polymer having two functional groups having reactivity with the isocyanate group independently and the isocyanate group of the diisocyanate compound. ,
   m and n represent numbers from 1 to 20, respectively.
   The polycarbodiimide compound according to claim 1, wherein p represents a number from 1 to 20.
7. In the above formula (1)
   R ¹ and R ² are residues obtained by removing the functional group from an organic compound having at least one functional group reactive with an isocyanate group, respectively, and the organic compound is reactive with an isocyanate group. Contains a (meth) acrylic polymer having at least one functional group having
   R ³ is a divalent residue obtained by removing two isocyanate groups from the diisocyanate compound, and the diisocyanate compound contains an aliphatic hydrocarbon group or an alicyclic hydrocarbon group that directly bonds with the two isocyanate groups. a plurality of ^{R 3,} equal to or different from each other,
   R ⁴ is a functional group obtained by removing the functional group from a divalent organic compound having two functional groups reactive with an isocyanate group, and the divalent organic compound is a glycol compound or a dicarboxylic acid compound. Yes,
   X ¹ and X ² are each independently formed by the reaction of the functional group of the (meth) acrylic polymer having at least one functional group having reactivity with the isocyanate group with the isocyanate group of the diisocyanate compound. Is a combination
   X ³ is a urethane bond,
   m and n represent numbers from 1 to 20, respectively.
   The polycarbodiimide compound according to claim 1, wherein p represents a number from 1 to 20.
8. The divalent organic compound having two functional groups reactive with the isocyanate group is a glycol compound, and the glycol compound is ethylene glycol, propylene glycol, 1,4-butanediol, diethylene glycol, dipropylene glycol, and the like. The polycarbodiimide compound according to claim 7, which is one or more selected from the group consisting of triethylene glycol, tripropylene glycol, polyethylene glycol, and polypropylene glycol.
9. Wherein X ³ is any group represented by the following formula (6) to (8), the polycarbodiimide compound according to any one of claims 1, 5 and 6.
   

   
10. The polycarbodiimide compound according to any one of claims 1 to 9, wherein X ¹ and X ² are any group represented by the following formulas (6) to (8).
    

    
11. The diisocyanate compounds are hexamethylene diisocyanate, cyclohexane-1,4-diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, methylcyclohexanediisocyanate, and 2,5 (2,6) -bis (isocyanatomethyl). The polycarbodiimide compound according to any one of claims 1 to 10, which is one or more selected from the group consisting of bicyclo [2.2.1] heptane.
12. An aqueous resin cross-linking agent containing the polycarbodiimide compound according to any one of claims 1 to 11 and an aqueous medium.
13. An aqueous resin composition containing the polycarbodiimide compound according to any one of claims 1 to 11 and an aqueous resin.
14. A method for producing a polycarbodiimide compound represented by the following formula (1), which comprises the following steps (A) and (B).
    Step (A): Carbodiimide reaction of the diisocyanate compound in the presence of a catalyst to obtain a polycarbodiimide precursor having isocyanate groups at both ends Step (B): Having at least one functional group capable of reacting with the isocyanate group The polycarbodiimide is a residue obtained by removing the functional group from the (meth) acrylic polymer and / or a residue obtained by removing the functional group from the (meth) acrylic polymer having two functional groups capable of reacting with an isocyanate group. Reaction process for introduction into the precursor R ¹ -X ^1- (R ³ -N = C = N) _m -R ^3- [X ³ -R ⁴ -X ^3- (R ³ -N = C = N) _n -R ³ ] _p -X ² -R ² (1)
    In equation (1)
    R ¹ and R ² are residues obtained by removing one of the functional groups from an organic compound having at least one functional group having reactivity with an isocyanate group, respectively.
    R ³ is a divalent residue obtained by removing two isocyanate groups from the diisocyanate compound, and the diisocyanate compound contains an aliphatic hydrocarbon group or an alicyclic hydrocarbon group that directly bonds with the two isocyanate groups. a plurality of ^{R 3,} equal to or different from each other,
    R ⁴ is a residue obtained by removing the functional group a functional group having a reactivity of an organic compound having two isocyanate groups, a plurality of R ^4, equal to or different from each other,
    At ^{least one of R 1} , R ² and R ⁴ is a residue obtained by removing the functional group from a (meth) acrylic polymer having a functional group reactive with an isocyanate group.
    X ¹ , X ² and X ³ are bonds formed independently by the reaction of the functional group of the organic compound with the isocyanate group of the diisocyanate compound.
    m and n represent numbers from 1 to 20, respectively.
    p represents a number from 0 to 20.