JP7618134B2 - Zinc Complex - Google Patents

Description

The present invention relates to a zinc complex.

It is already known that transparent methacrylic resins can be produced by dissolving zinc diacrylate and/or zinc dimethacrylate (hereinafter also referred to as zinc di(meth)acrylate) in methyl methacrylate and copolymerizing it.

However, zinc di(meth)acrylate has low solubility in methyl methacrylate, and in order to produce a methacrylic resin while maintaining properties such as transparency, it is necessary to keep the amount of zinc di(meth)acrylate used extremely small, which creates the problem that the obtained methacrylic resin cannot fully exhibit the properties derived from zinc di(meth)acrylate, such as heat resistance and mechanical strength.

As a solution to these problems, attempts have been made to improve the solubility of zinc di(meth)acrylate by adding water to methyl methacrylate, and to obtain a resin composition by copolymerization that has improved heat resistance without impairing the inherent transparency and mechanical properties of the methacrylic resin (Patent Document 1).

Zinc di(meth)acrylate is also known to be blended into rubber compositions to improve vulcanization properties, and to be used as a modifier for synthetic resins (Patent Documents 2 to 5).

Japanese Patent Application Publication No. 6-145255 Japanese Patent Application Publication No. 52-154436 Japanese Unexamined Patent Publication No. 53-83834 Japanese Unexamined Patent Publication No. 60-94434 Japanese Unexamined Patent Publication No. 2-218639

The inventors have noticed that the uses of zinc di(meth)acrylate are usually limited to those mentioned above. They have discovered that the reason behind this is that zinc di(meth)acrylate can only be dissolved in limited solvents such as water. Therefore, they thought that if zinc di(meth)acrylate could be dissolved in various solvents and monomers other than water, the versatility of zinc di(meth)acrylate would be significantly improved.

Therefore, the objective of the present invention is to provide a technology for increasing the solubility of zinc compounds having an alkenyloxycarbonyl group, such as zinc di(meth)acrylate or its derivatives, in various solvents and monomers.

One aspect of the present invention is a compound represented by the following general formula (I):

In the formula, each L is independently a ligand which is a nitrogen-containing organic compound, and each R is independently an alkenyl group having 2 to 10 carbon atoms which may be substituted at the α-position of the double bond with a methyl group.

One aspect of the present invention is a compound represented by the following general formula (II):
Zn(OCOR ^a ) ₂ ...(II)
wherein R ^a each independently represents an alkenyl group having 2 to 10 carbon atoms which may be substituted with a methyl group at the α-position of the double bond; and a nitrogen-containing organic compound in an amount of 2 or more molar equivalents relative to the zinc atom of the zinc carboxylate.

FIG. 1 shows the results of single crystal X-ray structure analysis.

In this specification, the range "X to Y" means "X or more and Y or less". When multiple "X to Y" are listed, for example, when "X1 to Y1 or X2 to Y2" is listed, the disclosure of each numerical value as the upper limit, the disclosure of each numerical value as the lower limit, and the combination of the upper and lower limits are all disclosed (i.e., the basis for the correction is lawful). Specifically, the correction with X1 or more, the correction with Y2 or less, the correction with X1 or less, the correction with Y2 or more, the correction with X1 to X2, the correction with X1 to Y2, etc. must all be considered lawful. In addition, unless otherwise specified, the operation and measurement of physical properties are performed at room temperature (20 to 25°C) and a relative humidity of 50±5% RH.

<Zinc complex>
One aspect of the present invention is a compound represented by the following general formula (I):

In the formula, each L is independently a ligand that is a nitrogen-containing organic compound, and each R is independently an alkenyl group having 2 to 10 carbon atoms, the α-position of the double bond of which may be substituted with a methyl group. Such a complex is soluble in various organic solvents and monomers other than water. In this specification, the organic solvent and/or (other) monomer may be referred to as a solvent. According to one aspect of the present invention, a technology can be provided for increasing the solubility of zinc compounds having an alkenyloxycarbonyl group, such as zinc di(meth)acrylate or a derivative thereof, in various solvents and monomers.

In one embodiment of the present invention, the alkenyl group having 2 to 10 carbon atoms, which may be substituted with a methyl group at the α-position of the double bond in R, may have a substituent. In one embodiment of the present invention, R is an alkenyl group having 2 to 9, 2 to 8, 2 to 7, 2 to 6, 2 to 5, or 2 to 4 carbon atoms, which may be substituted with a methyl group at the α-position of the double bond. In one embodiment of the present invention, the alkenyl group having 2 to 10 carbon atoms, which may be substituted with a methyl group at the α-position of the double bond, is a vinyl group, a 1-propenyl group, a 2-propenyl group (allyl group), an isopropenyl group, a 1-butenyl group, a 1-methyl-1-butenyl group, a 2-butenyl group, a 2-methyl-2-butenyl group, a 3-butenyl group, a 3-methyl-3-butenyl group, a 1-pentenyl group, a 1-methyl-1-pentenyl group, a 2-pentenyl group, a 2-methyl-2-pentenyl group, a 3-pentenyl group, a 3-methyl-3-pentenyl group, a 4-pentenyl group, a 5-pentenyl group, a 6-pentenyl group, a 7-pentenyl group, a 8-pentenyl group, a 9-pentenyl group, a 10-pentenyl group, a 11-pentenyl group, a 12-pentenyl group, a 13-pentenyl group, a 14-pentenyl group, a 15-pentenyl group, a 16-pentenyl group, a 17-pentenyl group, a 18-pentenyl group, a 21-pentenyl group, a 22-pentenyl group, a 23-pentenyl group, a 24-pentenyl group, a 25-pentenyl group, a 26-pentenyl group, a 27-pentenyl group, a 28-pentenyl group, a 29-pentenyl group, a 30-pentenyl group, a 31-pentenyl group, a 32-pentenyl group, a 33-pentenyl group, a 34-pentenyl group, a 35-pentenyl group, a 36-pent Examples of such groups include a 4-methyl-4-pentenyl group, a 1-hexenyl group, a 1-methyl-1-hexenyl group, a 2-hexenyl group, a 2-methyl-2-hexenyl group, a 3-hexenyl group, a 3-methyl-3-hexenyl group, a 4-hexenyl group, a 4-methyl-4-hexenyl group, a 5-hexenyl group, a 5-methyl-5-hexenyl group, a 6-heptenyl group, a 6-methyl-heptenyl group, a 7-octenyl group, a 7-methyl-7-octenyl group, an 8-nonyl group, an 8-methyl-8-nonyl group, a 9-decenyl group, and a 9-methyl-9-decenyl group.

In one embodiment of the present invention, the nitrogen-containing organic compound may be an organic compound containing one or more nitrogen atoms in the molecule. In one embodiment of the present invention, the nitrogen-containing organic compound may be a tertiary amine or a nitrogen-containing heterocyclic compound. In one embodiment of the present invention, the nitrogen-containing organic compound includes those that do not have a polymerizable group, such as an ethylenically unsaturated group.

(Tertiary amine)
In one embodiment of the present invention, the tertiary amine may be represented by N(R ¹ )(R ² )(R ³ ), where R ¹ , R ² and R ³ are each independently an alkyl group having 1 to 10 carbon atoms, which may be substituted with a substituent. Examples of the alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, a c-propyl group, an n-butyl group, an i-butyl group, a s-butyl group, a t-butyl group, a c-butyl group, an n-pentyl group, a c-pentyl group, an n-hexyl group, a c-hexyl group, an n-heptyl group, an n-octyl group, an n-nonyl group, and an n-decyl group. In one embodiment of the present invention, R ¹ , R ² and R ³ may each independently be an alkyl group having 1 to 8, 1 to 6, 1 to 4, 1 to 3, or 1 or 2 carbon atoms, which may be substituted with a substituent.

In one embodiment of the present invention, the substituents substituted on the alkyl group having 1 to 10 carbon atoms in R ¹ , R ² and R ³ may each independently be -OCOR ^b (wherein each R ^b is independently an alkenyl group having 2 to 10 carbon atoms and optionally substituted with a methyl group at the α-position of the double bond). In one embodiment of the present invention, the alkenyl group having 2 to 10 carbon atoms and optionally substituted with a methyl group at the α-position of the double bond in R ^b is an alkenyl group having 2 to 9, 2 to 8, 2 to 7, 2 to 6, 2 to 5, or 2 to 4 carbon atoms and optionally substituted with a methyl group at the α-position of the double bond. In one embodiment of the present invention, R The alkenyl group in ^b , which may be substituted with a methyl group at the α-position of the double bond having 2 to 10 carbon atoms, is a vinyl group, a 1-propenyl group, a 2-propenyl group (allyl group), an isopropenyl group, a 1-butenyl group, a 1-methyl-1-butenyl group, a 2-butenyl group, a 2-methyl-2-butenyl group, a 3-butenyl group, a 3-methyl-3-butenyl group, a 1-pentenyl group, a 1-methyl-1-pentenyl group, a 2-pentenyl group, a 2-methyl-2-pentenyl group, a 3-pentenyl group, a 3-methyl-3-pentenyl group, a 4-pentenyl group, a 4- Examples include a methyl-4-pentenyl group, a 1-hexenyl group, a 1-methyl-1-hexenyl group, a 2-hexenyl group, a 2-methyl-2-hexenyl group, a 3-hexenyl group, a 3-methyl-3-hexenyl group, a 4-hexenyl group, a 4-methyl-4-hexenyl group, a 5-hexenyl group, a 5-methyl-5-hexenyl group, a 6-heptenyl group, a 6-methyl-heptenyl group, a 7-octenyl group, a 7-methyl-7-octenyl group, an 8-nonyl group, an 8-methyl-8-nonyl group, a 9-decenyl group, and a 9-methyl-9-decenyl group.

In one embodiment of the present invention, the number of substituents on R ¹ , R ² and R ³ is 1, 2 or 3, respectively.

In one embodiment of the present invention, R ¹ , R ² and R ³ are an unsubstituted alkyl group having 1 to 10 carbon atoms, an unsubstituted alkyl group having 1 to 10 carbon atoms and an alkyl group having 1 to 10 carbon atoms substituted with -OCOR ^b , respectively.

In one embodiment of the present invention, R ¹ , R ² and R ³ are each independently an unsubstituted alkyl group having 1 to 10 carbon atoms.

(Nitrogen-containing heterocyclic compound)
In one embodiment of the present invention, the heterocycle in the nitrogen-containing heterocyclic compound may be a five-membered ring or a six-membered ring. The heteroatom may be at least one of an oxygen atom and a sulfur atom. In one embodiment of the present invention, the nitrogen-containing heterocyclic compound may have at least one of an aromatic ring and an alicyclic ring. In one embodiment of the present invention, the nitrogen-containing heterocyclic compound may be a single ring or a condensed ring. In one embodiment of the present invention, the nitrogen-containing heterocyclic compound may have one or two heteroatoms. Or it may have three.

In one embodiment of the present invention, specific examples of the nitrogen-containing heterocyclic compound include pyridine, N-methylpyrrolidone, quinoline, piperazine, piperidine, morpholine, carbazole, triazine, etc. Using pyridine as the nitrogen-containing heterocyclic compound can improve the stability of the zinc complex as a crystal.

In one embodiment of the present invention, the nitrogen-containing heterocyclic compounds may be used alone or in combination of two or more.

In one embodiment of the present invention, the zinc complex represented by general formula (I) is represented by the following general formula (II):
Zn(OCOR ^a ) ₂ ...(II)
wherein R ^a are each independently an alkenyl group having 2 to 10 carbon atoms, the α-position of the double bond of which may be substituted with a methyl group, and a nitrogen-containing organic compound in an amount of 2 or more molar equivalents relative to the zinc atom of the zinc carboxylate. If the molar equivalent of the nitrogen-containing organic compound relative to the zinc atom of the zinc carboxylate is less than 2 molar equivalents, it is difficult to obtain a dicoordinated complex.

Therefore, in another aspect of the present invention, one embodiment of the present invention is a compound represented by the following general formula (II):
Zn(OCOR ^a ) ₂ ...(II)
wherein R ^a's are each independently an alkenyl group having 2 to 10 carbon atoms which may be substituted with a methyl group at the α-position of the double bond; and a nitrogen-containing organic compound in an amount of 2 or more molar equivalents relative to the zinc atom of the zinc carboxylate.

In one embodiment of the present invention, the alkenyl group having 2 to 10 carbon atoms and optionally substituted with a methyl group at the α-position of the double bond in R ^a may have a substituent. In one embodiment of the present invention, the alkenyl group having 2 to 10 carbon atoms and optionally substituted with a methyl group at the α-position of the double bond in R ^a is an alkenyl group having 2 to 9, 2 to 8, 2 to 7, 2 to 6, 2 to 5, or 2 to 4 carbon atoms and optionally substituted with a methyl group at the α-position of the double bond. In one embodiment of the present invention, R The alkenyl group in ^a, which may be substituted with a methyl group at the α-position of the double bond having 2 to 10 carbon atoms, is a vinyl group, a 1-propenyl group, a 2-propenyl group (allyl group), an isopropenyl group, a 1-butenyl group, a 1-methyl-1-butenyl group, a 2-butenyl group, a 2-methyl-2-butenyl group, a 3-butenyl group, a 3-methyl-3-butenyl group, a 1-pentenyl group, a 1-methyl-1-pentenyl group, a 2-pentenyl group, a 2-methyl-2-pentenyl group, a 3-pentenyl group, a 3-methyl-3-pentenyl group, a 4-pentenyl group, a 4- Examples include a methyl-4-pentenyl group, a 1-hexenyl group, a 1-methyl-1-hexenyl group, a 2-hexenyl group, a 2-methyl-2-hexenyl group, a 3-hexenyl group, a 3-methyl-3-hexenyl group, a 4-hexenyl group, a 4-methyl-4-hexenyl group, a 5-hexenyl group, a 5-methyl-5-hexenyl group, a 6-heptenyl group, a 6-methyl-heptenyl group, a 7-octenyl group, a 7-methyl-7-octenyl group, an 8-nonyl group, an 8-methyl-8-nonyl group, a 9-decenyl group, and a 9-methyl-9-decenyl group.

In one embodiment of the present invention, the nitrogen-containing organic compound to be mixed with the zinc carboxylate may be the same as that described above (nitrogen-containing heterocyclic compound).

In one embodiment of the present invention, the molar equivalent of the nitrogen-containing organic compound relative to the zinc atom of the zinc carboxylate is 30 molar equivalents or less, 25 molar equivalents or less, 10 molar equivalents or less, 8 molar equivalents or less, 6 molar equivalents or less, 4.5 molar equivalents or less, 4 molar equivalents or less, 3.5 molar equivalents or less, 3 molar equivalents or less, or 2.5 molar equivalents or less.

As described above, the compound represented by the following general formula (II):
Zn(OCOR ^a ) ₂ ...(II)
In the formula, R ^a each independently represents an alkenyl group having 2 to 10 carbon atoms, the α-position of the double bond of which may be substituted with a methyl group (e.g., zinc diacrylate) is generally poorly soluble in water and organic solvents/monomers other than methanol (or alcohol). Therefore, it is difficult to use it in liquid phase polymerization, and it has been mostly used as a rubber modifier by solid phase polymerization.

According to one aspect of the present invention, as described above, a nitrogen-containing organic compound is used, and the solubility of the zinc carboxylate (e.g., zinc diacrylate) in an organic solvent/monomer can be dramatically improved. This is believed to be because the nitrogen-containing organic compound (e.g., 2 to 4 molecules) is coordinated/complexed to the zinc carboxylate (e.g., zinc diacrylate), resulting in improved solubility.

In one embodiment of the present invention, the zinc complex may exhibit a tetrahedral structure.

In one embodiment of the present invention, the zinc complex is soluble in various organic solvents and monomers and is polymerizable.

In one embodiment of the present invention, the method of mixing the zinc carboxylate with the nitrogen-containing organic compound is not particularly limited. The nitrogen-containing organic compound may be added to the zinc carboxylate, or the zinc carboxylate may be added to the nitrogen-containing organic compound. In one embodiment of the present invention, the zinc carboxylate with the nitrogen-containing organic compound may be mixed together with various solvents and/or various monomers, and there is no particular limit to the order of addition.

<Solubility of zinc complexes>
The zinc complex according to one embodiment of the present invention has excellent solubility in various monomers and organic solvents. In one embodiment of the present invention, the indicator of solubility is transmittance. This transmittance can be calculated by the measurement method described in the Examples. More specifically, it can mean the transmittance at a wavelength of 660 nm using a spectrophotometer of a monomer/organic solvent (composition temperature: 25° C.) containing a zinc complex (zinc carboxylate) at a concentration of 2.5 mass % calculated as zinc salt.

In one embodiment of the present invention, the compound is represented by the following general formula (I):

In the formula, L is independently a ligand which is a nitrogen-containing organic compound, and R is independently an alkenyl group having 2 to 10 carbon atoms, the α-position of the double bond of which may be substituted with a methyl group, and the zinc complex contains the zinc complex at a concentration of 2.5% by mass calculated as a zinc salt. The transmittance in at least one of the other monomer having an ethylenically unsaturated bond group and an organic solvent is 90% or more. The reason why it is written as "the 'other' monomer having an ethylenically unsaturated bond" is to distinguish it from R, which also has an ethylenically unsaturated bond.

In one embodiment of the present invention, the compound represented by the following general formula (II):
Zn(OCOR ^a ) ₂ ...(II)
wherein R ^a's are each independently an alkenyl group having 2 to 10 carbon atoms, the α-position of which may be substituted with a methyl group, and a nitrogen-containing organic compound in an amount of 2 or more molar equivalents relative to the zinc atom of the zinc carboxylate; the zinc complex obtained by mixing the zinc complex has a concentration of 2.5% by mass calculated as the zinc salt and has a transmittance of 90% or more in at least one of another monomer having an ethylenically unsaturated bond group and an organic solvent.

The following general formula (II):
Zn(OCOR ^a ) ₂ ...(II)
In the formula, R ^a each independently represents an alkenyl group having 2 to 10 carbon atoms, the α-position of the double bond of which may be substituted with a methyl group. The zinc carboxylate shown has excellent solubility in methanol even when not complexed. In that sense, the organic solvent does not need to be methanol. In one embodiment of the present invention, the organic solvent does not contain alcohol. In one embodiment of the present invention, the organic solvent does not contain methanol.

In one embodiment of the present invention, the transmittance may be, for example, 91% or more, 92% or more, 93% or more, 94% or more, 95% or more, 96% or more, 97% or more or 98% or more.

(Other Monomers Having Ethylenically Unsaturated Bond Groups)
In one embodiment of the present invention, the other monomer having an ethylenically unsaturated bond group is a zinc complex and/or a monomer represented by the following general formula (II):
Zn(OCOR ^a ) ₂ ...(II)
In the formula, R ^a each independently represents an alkenyl group having 2 to 10 carbon atoms, the α-position of the double bond of which may be substituted with a methyl group. There are no particular limitations on the type of compound as long as it is copolymerizable with the zinc salt of a carboxylate shown in the formula, and examples of such compounds include (meth)acrylic acid ester compounds ((meth)acrylic acid alkyl) such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, octyl (meth)acrylate, dodecyl (meth)acrylate, and octadecyl (meth)acrylate; olefinic hydrocarbons such as ethylene, propylene, and vinyl chloride, or halogen-substituted derivatives thereof; aromatic vinyl compounds such as styrene and methylstyrene; vinyl compounds of monovalent carboxylic acids such as vinyl acetate and vinyl propionate. Examples of the monomers include ester compounds, unsaturated alcohol compounds such as (meth)allyl alcohol and crotonic alcohol, α,β-ethylenically unsaturated carboxylic acid compounds such as (meth)acrylic acid, crotonic acid and cinnamic acid, unsaturated dibasic carboxylic acids such as maleic acid, fumaric acid and itaconic acid, monoester compounds of monohydric alcohols and unsaturated dibasic carboxylic acids such as maleic acid monomethyl ester and maleic acid monoallyl ester, and polyvinyl compounds such as divinylbenzene, ethylene glycol diacrylate, ethylene glycol dimethacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate and diallyl maleate. These other monomers having a vinyl group can be used alone or in combination of two or more kinds. In one embodiment of the present invention, the number of carbon atoms of the alkyl in the (meth)acrylate is 1 to 18, 1 to 15, 1 to 10, 1 to 7, or 1 to 4. In one embodiment of the present invention, the alkyl in the (meth)acrylate may be substituted with a hydroxyl group. In one embodiment of the present invention, the alkyl in the alkyl (meth)acrylate may be substituted with an alkoxy group. In one embodiment of the present invention, the alkoxy group may have 1 to 5 carbon atoms, or alternatively, 1 to 3 carbon atoms. In one embodiment of the present invention, the alkyl (meth)acrylate may be substituted with an alkenyloxy group. In one embodiment of the present invention, the alkyl (meth)acrylate may have an alkenyloxy group and an ether bond. In one embodiment of the present invention, the alkenyloxy group may have 1 to 3 carbon atoms.

In this specification, if another monomer having an ethylenically unsaturated bond group also falls under the category of a nitrogen-containing organic compound, it is classified as a nitrogen-containing organic compound. Therefore, the other monomer having an ethylenically unsaturated bond group in this specification is not a nitrogen-containing organic compound.

In one embodiment of the present invention, the other monomer may be an oligomer. Here, an oligomer means one having two or more repeating units, which may also be recognized as a polymer. In this embodiment, when the other monomer is an oligomer (polymer), it may be less than 5% by mass, 4% by mass or less, 3% by mass or less, 2% by mass or less, 1% by mass or less, 0.5% by mass or less, or 0% by mass of the total mass of the monomer.

(Organic solvent)
The organic solvent may be an organic compound that is liquid at room temperature and normal pressure (25° C., 1 atm). When the organic solvent also corresponds to a nitrogen-containing organic compound, it is classified as a nitrogen-containing organic compound. Thus, the organic solvent in this specification is not a nitrogen-containing organic compound. In one embodiment of the present invention, the organic solvent includes an organic solvent that does not have a polymerizable group such as an ethylenically unsaturated group. This embodiment can more effectively impart properties derived from zinc di(meth)acrylate, such as heat resistance.

In one embodiment of the present invention, the organic solvent is not particularly limited, but examples thereof include alcohols such as methanol, ethanol, propanol, butanol, methoxybutanol, glycol ethers (e.g., glycol ethers such as ethylene glycol monobutyl ether (butyl cellosolve), propylene glycol monomethyl ether, and propylene glycol monomethyl ether acetate), and polyfunctional alcohols (e.g., ethylene glycol, propylene glycol, and trimethylolpropane); esters such as methyl acetate, ethyl acetate, butyl acetate, ethyl lactate, methyl lactate, and butyl lactate; hydrocarbons such as toluene and xylene, ketones such as acetone and methyl ethyl ketone; and ethers (diethyl ether, diphenyl ether, ethylene glycol diethyl ether, tetrahydrofuran, and the like). These organic solvents can be used alone or in combination of two or more.

<Zinc Complex Composition>
In one embodiment of the present invention, there is provided a composition comprising the zinc complex and a solvent, the solvent being substantially composed of another monomer having an ethylenically unsaturated bond group and/or an organic solvent.
Zn(OCOR ^a ) ₂ ...(II)
A composition is provided which comprises a zinc carboxylate, wherein R ^a is independently an alkenyl group having 2 to 10 carbon atoms, the α-position of the double bond of which may be substituted with a methyl group, a nitrogen-containing organic compound, and a solvent, wherein the solvent consists essentially of other monomers having an ethylenically unsaturated bond group and/or an organic solvent. Here, "consisting essentially of" means that the solvent does not contain any medium other than the monomer having an ethylenically unsaturated bond group and the organic solvent, or if it does contain any medium, the amount of such medium in the solvent is, for example, 5% by mass or less, 1% by mass or less, 0.1% by mass or less, 0.05% by mass or less, 0.01% by mass or less, 0.005% by mass or less, or 0.001% by mass or less. In one embodiment of the present invention, the solvent does not substantially contain water. Here, "substantially free of water" not only encompasses cases where the solvent does not contain any water at all, but also conceptually encompasses cases where the solvent unavoidably contains moisture from the air, or cases where the solvent contains a very small amount of water, for example, 5% by mass or less, 1% by mass or less, 0.1% by mass or less, 0.05% by mass or less, 0.01% by mass or less, 0.005% by mass or less, or 0.001% by mass or less.

In one embodiment of the present invention, the explanation given in <Solubility of zinc complex> may be applied to the explanation of the other monomer having an ethylenically unsaturated bond group and the type of organic solvent. As described above, zinc carboxylate has excellent solubility in methanol even if it is not complexed. In that sense, the organic solvent does not have to be methanol. Zinc carboxylate may have excellent solubility in alcohol. Therefore, in one embodiment of the present invention, the organic solvent does not have to be alcohol. In one embodiment of the present invention, the organic solvent does not include alcohol. In one embodiment of the present invention, the organic solvent does not include methanol.

In one embodiment of the present invention, the proportion of other monomers having ethylenically unsaturated bond groups in the composition may be 70% by weight or more, 75% by weight or more, 80% by weight or more, 85% by weight or more, 90% by weight or more, or 95% by weight or more. In one embodiment of the present invention, the proportion of other monomers having ethylenically unsaturated bond groups in the composition may be 99.5% by weight or less, 97.5% by weight or less, 96% by weight or less, 94% by weight or less, 92% by weight or less, 90% by weight or less, 88% by weight or less, 86% by weight or less, or 84% by weight or less.

In one embodiment of the present invention, a compound represented by the following general formula (II):
Zn(OCOR ^a ) ₂ ...(II)
In the formula, R ^a each independently represents an alkenyl group having 2 to 10 carbon atoms which may be substituted with a methyl group at the α-position of the double bond, and the proportion of the zinc carboxylate may be 0.01 parts by mass to 40 parts by mass, 0.01 to 30 parts by mass, 0.01 to 20 parts by mass, or 0.01 to 10 parts by mass.

In one embodiment of the present invention, the proportion of organic solvent in the composition may be 60% by weight or more, 70% by weight or more, 75% by weight or more, 80% by weight or more, 85% by weight or more, 90% by weight or more, or 95% by weight or more. In one embodiment of the present invention, the proportion of organic solvent in the composition may be 97.5% by weight or less, 96% by weight or less, 94% by weight or less, 92% by weight or less, 90% by weight or less, 88% by weight or less, 86% by weight or less, 84% by weight or less, 80% by weight or less, 75% by weight or less, 70% by weight or less, or 65% by weight or less.

In one embodiment of the present invention, the proportion of the zinc complex in the composition may be 0.5% by weight or more, 0.7% by weight or more, 1% by weight or more, 1.2% by weight or more, 1.5% by weight or more, 1.7% by weight or more, 2% by weight or more, 2.2% by weight or more, 2.4% by weight or more, 2.6% by weight or more, 2.8% by weight or more, 3% by weight or more, 3.5% by weight or more, 4% by weight or more, 4.5% by weight or more, 5% by weight or more, 5.5% by weight or more, 6% by weight or more, 6.5% by weight or more, 7% by weight or more, 10% by weight or more, 15% by weight or more, 20% by weight or more, 25% by weight or more, or 30% by weight or more. In one embodiment of the present invention, the proportion of the zinc complex in the composition may be 55% by weight or less, 50% by weight or less, or 45% by weight or less.

In one embodiment of the present invention, the proportion of the zinc carboxylate in the composition may be 0.1% by weight or more, 0.3% by weight or more, 0.5% by weight or more, 0.7% by weight or more, 1% by weight or more, 1.2% by weight or more, 1.5% by weight or more, 1.7% by weight or more, 2% by weight or more, 2.2% by weight or more, 2.4% by weight or more, 2.6% by weight or more, 2.8% by weight or more, 3% by weight or more, 4% by weight or more, 5% by weight or more, 6% by weight or more, 7% by weight or more, 8% by weight or more, or 9% by weight or more. In one embodiment of the present invention, the proportion of the zinc carboxylate in the composition may be 40% by weight or less, 30% by weight or less, or 25% by weight or less.

In one embodiment of the present invention, the molar ratio of the nitrogen-containing organic compound to the zinc atom of the zinc carboxylate is 2 moles or more. In one embodiment of the present invention, the molar equivalent of the nitrogen-containing organic compound to the zinc atom of the zinc carboxylate is 30 molar equivalents or less, 20 molar equivalents or less, 10 molar equivalents or less, 8 molar equivalents or less, 6 molar equivalents or less, 4.5 molar equivalents or less, 4 molar equivalents or less, 3.5 molar equivalents or less, 3 molar equivalents or less, or 2.5 molar equivalents or less.

In one embodiment of the present invention, the composition containing the zinc complex and a solvent may further contain a polymerization initiator.
Zn(OCOR ^a ) ₂ ...(II)
wherein R ^a's are each independently an alkenyl group having 2 to 10 carbon atoms which may be substituted with a methyl group at the α-position of the double bond. The composition comprising a zinc carboxylate, a nitrogen-containing organic compound, and a solvent may further comprise a polymerization initiator.

(Polymerization initiator)
In one embodiment of the present invention, the polymerization initiator may be a photopolymerization initiator or a thermal polymerization initiator. The photopolymerization initiator is not particularly limited, and may be benzoin and its alkyl ethers such as benzoin, benzoin methyl ether, and benzoin ethyl ether; acetophenones such as acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, and 4-(1-t-butyldioxy-1-methylethyl)acetophenone; alkylphenones such as 1-hydroxycyclohexyl phenyl ketone and 2-hydroxy-2-methyl-1-phenylpropan-1-one; anthraquinones such as 2-methylanthraquinone, 2-amyl anthraquinone, 2-t-butyl anthraquinone, and 1-chloro anthraquinone; thioxanthones such as 2,4-dimethylthioxanthone, 2,4-diisopropylthioxanthone, and 2-chlorothioxanthone; and ketals such as acetophenone dimethyl ketal and benzyl dimethyl ketal. benzophenone, 4-(1-t-butyldioxy-1-methylethyl)benzophenone, 3,3',4,4'-tetrakis(t-butyldioxycarbonyl)benzophenone and the like benzophenones; 1,2-octanedione, 1-[4-(phenylthio)-2-(O-benzoyloxime)], ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl], 1-(0-acetyloxime) and the like oxime esters; 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-propan-1-one; 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone-1; 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide and the like acylphosphine oxides; xanthones and the like. These may be used alone or in combination of two or more.

In one embodiment of the present invention, the proportion of the photopolymerization initiator in the composition may be 0.01% by weight or more, 0.05% by weight or more, 0.1% by weight or more, 0.2% by weight or more, 0.3% by weight or more, or 0.4% by weight or more. In one embodiment of the present invention, the proportion of the photopolymerization initiator in the composition may be 20% by weight or less, 10% by weight or less, or 5% by weight or less.

In one embodiment of the present invention, the composition containing the zinc complex and the solvent may further contain known additives such as plasticizers, inorganic fillers, colorants, reinforcing agents, modifiers, stabilizers, extenders, release agents, and dispersants. These may be used alone or in combination of two or more. In one embodiment of the present invention, the composition may be represented by the following general formula (II):
Zn(OCOR ^a ) ₂ ...(II)
The composition containing a zinc carboxylate, a nitrogen-containing organic compound, and a solvent, represented by the formula: wherein R ^a is each independently an alkenyl group having 2 to 10 carbon atoms, the α-position of the double bond of which may be substituted with a methyl group, may further contain known additives such as a plasticizer, an inorganic filler, a colorant, a reinforcing agent, a modifier, a stabilizer, an extender, a release agent, a dispersant, etc. These may be used alone or in combination of two or more kinds.

In one embodiment of the present invention, in producing the composition, the method of mixing the zinc complex with the solvent is not particularly limited. The solvent may be added to the zinc complex, or the zinc complex may be added to the solvent. In addition, in one embodiment of the present invention, in producing the composition, a compound represented by the following general formula (II):
Zn(OCOR ^a ) ₂ ...(II)
In the formula, R ^a each independently represents an alkenyl group having 2 to 10 carbon atoms, the α-position of the double bond of which may be substituted with a methyl group. Similarly, the method of mixing the zinc carboxylate, the nitrogen-containing organic compound, and the solvent is not particularly limited. They may be added in any order.

In one embodiment of the present invention, when a polymerization initiator or additive is further added to produce the composition, the method of mixing these is similarly not particularly limited. They may be added in any order.

<Ionomer and its manufacturing method>
In one embodiment of the present invention, there is provided a method for producing an ionomer containing zinc atoms comprising polymerizing the above composition.

In one embodiment of the present invention, the polymerization of the composition may be thermal polymerization or photopolymerization. The light source used for exposure to light in the photopolymerization in one embodiment of the present invention is not particularly limited, but may be a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, a xenon lamp, a metal halide lamp, an ultraviolet LED, or the like. In addition, the exposure dose (ultraviolet illuminance) in the photopolymerization in one embodiment of the present invention is not particularly limited, but may be, for example, 0.1 to 600 mW/cm ² , 1 to 400 mW/cm ² , or 5 to 200 mW/cm ² for 0.1 seconds to 60 minutes, 1 second to 45 minutes, or 5 seconds to 30 minutes.

By polymerizing the above composition, Zn(OCOR ^a ) ₂ ... (II)
In the formula, R ^a each independently represents an alkenyl group having 2 to 10 carbon atoms in which the α-position of the double bond may be substituted with a methyl group, and an ionomer including a structural unit derived from a zinc carboxylate and a structural unit derived from a monomer having an ethylenically unsaturated bond group other than the structural unit derived from the zinc carboxylate can be provided.

After polymerization, nitrogen-containing organic compounds such as triethylamine can be removed by drying under reduced pressure. This makes it possible to carry out liquid phase polymerization, which was previously difficult, and is expected to lead to a wide range of applications.

Although the embodiments of the present invention have been described in detail, it is clear that the same is illustrative and exemplary and not limiting, and the scope of the present invention should be interpreted by the appended claims.

The present invention may include the following aspects and configurations:

1. The following general formula (I):

A zinc complex represented by the formula: In this formula, each L is independently a ligand which is a nitrogen-containing organic compound, and each R is independently an alkenyl group having 2 to 10 carbon atoms, the α-position of the double bond of which may be substituted with a methyl group.

2. The following general formula (II):
Zn(OCOR ^a ) ₂ ...(II)
wherein R ^a 's each independently represent an alkenyl group having 2 to 10 carbon atoms, the α-position of the double bond of which may be substituted with a methyl group; and a nitrogen-containing organic compound in an amount of 2 or more molar equivalents relative to the zinc atom of the zinc carboxylate.

3. The zinc complex according to 2., wherein the molar equivalent is 4 molar equivalents or less.

4. The zinc complex according to 2. or 3., wherein each R ^a is independently an alkenyl group having 2 to 4 carbon atoms and optionally substituted with a methyl group at the α-position of the double bond.

5. The zinc complex according to any one of 1 to 4, wherein the nitrogen-containing organic compound is a tertiary amine or a nitrogen-containing heterocyclic compound.

6. The zinc complex according to 5., wherein the tertiary amine is represented by N(R ¹ )(R ² )(R ³ ), where R ¹ , R ² and R ³ are each independently an alkyl group having 1 to 10 carbon atoms which may be substituted with a substituent, and the substituent is -OCOR ^b (wherein each R ^b is independently an alkenyl group having 2 to 10 carbon atoms which may be substituted with a methyl group at the α-position of the double bond).

7. The zinc complex described in 5., wherein the nitrogen-containing heterocyclic compound is pyridine.

8. The zinc complex according to any one of 1 to 7, wherein the transmittance of another monomer having an ethylenically unsaturated bond group containing the zinc complex at a concentration of 2.5% by mass calculated as a zinc salt is 90% or more.

9. The zinc complex according to any one of 1 to 7, wherein the zinc complex has a transmittance of 90% or more in an organic solvent containing the zinc complex at a concentration of 2.5% by mass calculated as a zinc salt.

10. A composition comprising the zinc complex according to any one of 1. to 9. and a solvent, wherein the solvent consists essentially of other monomers having an ethylenically unsaturated bond group and/or an organic solvent.

11. A compound represented by the following general formula (II):
Zn(OCOR ^a ) ₂ ...(II)
wherein R ^a's are each independently an alkenyl group having 2 to 10 carbon atoms, the α-position of which may be substituted with a methyl group; a nitrogen-containing organic compound; and a solvent, wherein the solvent consists essentially of other monomers having an ethylenically unsaturated bond group and/or an organic solvent.

12. The composition described in 11., wherein the proportion of the zinc carboxylate in the composition is 0.1 mass% or more, and the molar ratio of the nitrogen-containing organic compound to the zinc atoms of the zinc carboxylate is 2 moles or more.

13. A method for producing an ionomer containing zinc atoms, comprising polymerizing a composition described in any one of 10. to 12.

14. A compound represented by the following general formula (II):
Zn(OCOR ^a ) ₂ ...(II)
In the formula, R ^a each independently represents an alkenyl group having 2 to 10 carbon atoms, the α-position of the double bond of which may be substituted with a methyl group, and an ionomer comprising: a structural unit derived from a zinc carboxylate; and a structural unit derived from a monomer having an ethylenically unsaturated bond group other than the structural unit derived from the zinc carboxylate.

The present invention will be explained in more detail below with reference to examples and comparative examples, but the present invention should not be interpreted as being limited to these examples and comparative examples, and examples obtained by appropriately combining the technical means disclosed in each example are also included in the scope of the present invention. Unless otherwise noted, measurements were taken at room temperature (20-25°C) and a relative humidity of 50±5% RH.

<Confirmation of solubility>
(Visual results)
Mixtures (75° C.) of zinc diacrylate (ZN-DA), toluene, and various dissolution aids having the compositions shown in the table below were prepared, and the solubility of zinc diacrylate was visually confirmed.

As described above, zinc diacrylate can be dissolved in toluene containing various dissolution aids, but zinc diacrylate cannot be dissolved in toluene that does not contain any dissolution aids.

<Identification of zinc diacrylate-2-pyridine ligand>
( ^1H -NMR)
A mixture of zinc diacrylate, toluene, and pyridine as a dissolution aid, as shown in Table 1, was concentrated (dried under reduced pressure) to obtain a powder.

40 mg of the powder was taken and dissolved in 2,000 mg of deuterated toluene, and ¹ H-NMR was measured using a JNM-ECZ600R manufactured by JEOL Ltd. The results are shown in the following table.

(Thermogravimetric measurement)
The thermal mass of the powder was measured using a Hitachi STA7200 TG/DTA. Specifically, the mass loss rate at the time of constant weight when held at 100° C. under a nitrogen flow was regarded as the amount of free ligands and compared with the theoretical value. The results are shown in the table below.

(Bromine number measurement)
The bromine number of the powder was measured according to JIS K 2605:1996 and compared with the theoretical value. The results are shown in the table below.

(Elemental Analysis)
The elemental analysis of the powder was carried out using a Vario EL Cube manufactured by Elementar, and the results were compared with theoretical values.

(Single crystal X-ray structure analysis)
The single crystal X-ray structure analysis of the above powder was performed using a single crystal X-ray structure analysis Rigaku Saturn724+ diffractometer with MoKα radiation (λ=0.71075 Å) monochromated by a graphite monochromator, and the data was collected using CrystalClear-SM 1.4.0 SP1 and processed with CrysAlisPro 171.41.105a 64 bit. The results are shown in FIG. 1.

<Confirmation of solubility>
(Solubility Measurement)
Next, the solubility of zinc diacrylate in various solvents and various monomers was evaluated by the following method. That is, in the comparative example (without triethylamine (TEA)), 1 g of zinc diacrylate was prepared in a sealed container. Various solvents and various monomers (25°C) were gradually added thereto while stirring, and it was visually confirmed that the solution was completely dissolved, and the solubility (mass%) was calculated from the mass of the solution (25°C) at that time. In the example (with triethylamine (TEA)), 1 g of zinc diacrylate was further added with 2 g of triethylamine (4.1 equivalents/zinc diacrylate) and the solubility (mass%) of zinc diacrylate in various solvents and various monomers was measured in the same manner as in the comparative example, except that a solution was prepared in a sealed container in which 1 g of zinc diacrylate was further added with 2 g of triethylamine (4.1 equivalents/zinc diacrylate).

(Transmittance Measurement)
As an index showing the effect of the solubilizing agent, the transmittance was measured in various solvents and various monomers when the solubilizing agent (TEA) was 2.5% by mass as the liquid.

More specifically, samples (25°C) were prepared with the following mass ratios, and the transmittance (%) at a wavelength of 660 nm was measured using a spectrophotometer (model number: V-650, manufactured by JASCO Corporation).

In the comparative example (without TEA), the ratio of various solvents and various monomers to zinc diacrylate was 97.5:2.5.
In the examples (TEA added), the ratio of various solvents/various monomers: zinc diacrylate: triethylamine was 92.5:2.5:5.0.

As described above, the use of a dissolution aid dramatically improved the solubility of zinc diacrylate in various solvents and monomers. In addition, the presence or absence of a dissolution aid resulted in a significant difference in the transmittance in various solvents and monomers. In one embodiment of the present invention, the indicator of "solubility" is a transmittance of 90% or more.

<Photopolymerization test results>
(Glass Transition Temperature)
A mixture was prepared by mixing the monomers, polymerization initiator, zinc diacrylate, and dissolution aid shown in the following table. The order of mixing these is not particularly limited.

Then, a structure was prepared by sandwiching a double-sided tape between two transparent glass plates as a spacer at both ends to provide a gap of about 2 mm thickness, and each mixture (2 g) was poured into the gap, and UV irradiation was performed for 30 minutes at a UV intensity of 170 mW/ ^cm2 using HLR100T-2 manufactured by Sen Special Light Sources Co., Ltd. Thereafter, the mixture was peeled off from the glass plate to obtain a polymer. The glass transition temperature of each obtained polymer was measured by differential thermal analysis (DTA).

(Mass reduction rate)
The polymers obtained in Comparative Example 1 and Examples 1-1 to 1-3 were heated, and the temperatures at which the mass reduction rates reached 5 mass %, 10 mass %, and 50 mass % were measured.

In addition, in measuring the glass transition temperature and mass loss rate in Examples 2-1 to 2-3, in order to suppress the influence of volatile matters (mainly triethylamine) remaining in the obtained polymer, a drying treatment was performed under conditions of 70°C, 0.004 MPa, and 1 hour before measuring the glass transition temperature and mass loss rate.

As shown in Examples 1-1 to 1-3 and Examples 2-1 to 2-3, the glass transition temperature of the polymer obtained by polymerizing methyl methacrylate and butyl acrylate in the presence of a dissolution aid and zinc diacrylate is higher than the glass transition temperature of the polymer of methyl methacrylate and butyl acrylate in Comparative Example 1. This shows that the addition of a dissolution aid and zinc diacrylate has the effect of improving heat resistance.

It is noteworthy that, when comparing Examples 1-1 to 1-3, which use a polymerizable dissolution aid A (2-dimethylaminoethyl acrylate), with Examples 2-1 to 2-3, which use a non-polymerizable dissolution aid B (triethylamine), the latter is able to more effectively impart the properties (heat resistance) derived from zinc di(meth)acrylate.

This application is based on Japanese Patent Application No. 2022-200007 filed on December 15, 2022, the disclosure of which is incorporated by reference in its entirety.

Claims (14)

The following general formula (II):
Zn(OCOR ^a ) ₂ ...(II)
In the formula, each R ^a is independently an alkenyl group having 2 to 10 carbon atoms, the α-position of the double bond of which may be substituted with a methyl group;
a nitrogen-containing organic compound in an amount of 2 or more molar equivalents relative to the zinc atom of the zinc carboxylate;
and
the nitrogen-containing organic compound is a nitrogen-containing heterocyclic compound or a tertiary amine,
the nitrogen-containing heterocyclic compound is N-methylpyrrolidone, quinoline, piperazine, piperidine, morpholine, carbazole, or triazine ;
A zinc complex in which the tertiary amine is represented by N(R ¹ )(R ² )(R ³ ), where R ¹ , R ² and R ³ are each independently an alkyl group having 1 to 10 carbon atoms which may be substituted with a substituent, and when substituted with a substituent, the substituent is each independently -OCOR ^b (wherein each R ^b is independently an alkenyl group having 2 to 10 carbon atoms which may be substituted with a methyl group at the α-position of the double bond), with the proviso that when the tertiary amine is dimethylaminoethyl methacrylate, the α-position of R ^a is not substituted with a methyl group, and the nitrogen-containing organic compound is not triethylamine. 2. The zinc complex of claim 1 , wherein the molar equivalents is 30 molar equivalents or less. 2. The zinc complex according to claim 1 , which has a transmittance of 90% or more in another monomer having an ethylenically unsaturated bond group, containing the zinc complex at a concentration of 2.5% by mass calculated as a zinc salt. 2. The zinc complex according to claim 1 , which has a transmittance of 90% or more in an organic solvent containing the zinc complex at a concentration of 2.5% by mass in terms of a zinc salt. A zinc complex;
A solvent;
A composition comprising:
The zinc complex is represented by the following general formula (I):

In the formula, each L is independently a ligand which is a nitrogen-containing organic compound which is a nitrogen-containing heterocyclic compound or a tertiary amine, and each R is independently an alkenyl group having 2 to 10 carbon atoms and which may be substituted with a methyl group at the α-position of the double bond.
or
The following general formula (II):
Zn(OCOR ^a ) ₂ ...(II)
wherein R ^a 's each independently represent an alkenyl group having 2 to 10 carbon atoms, the α-position of the double bond of which may be substituted with a methyl group; and a nitrogen-containing organic compound which is a nitrogen-containing heterocyclic compound or a tertiary amine, in an amount of 2 or more molar equivalents relative to the zinc atom of the zinc carboxylate,
wherein the nitrogen-containing heterocyclic compound is pyridine, N-methylpyrrolidone, quinoline, piperazine, piperidine, morpholine, carbazole, or triazine, the tertiary amine is represented by N(R ¹ )(R ² )(R ³ ), where R ¹ , R ² , and R ³ are each independently an alkyl group having 1 to 10 carbon atoms which may be substituted with a substituent, and when substituted with a substituent, the substituent is each independently -OCOR ^b (wherein each R ^b is independently an alkenyl group having 2 to 10 carbon atoms which may be substituted with a methyl group at the α-position of the double bond);
A composition, wherein the solvent consists essentially of other monomers having ethylenically unsaturated bond groups and/or an organic solvent, with the proviso that the organic solvent does not contain alcohol. The composition according to claim 5, wherein the composition has a transmittance of 90% or more when the zinc complex is contained in a concentration of 2.5% by mass calculated as a zinc salt . The following general formula (II):
Zn(OCOR ^a ) ₂ ...(II)
In the formula, each R ^a is independently an alkenyl group having 2 to 10 carbon atoms, the α-position of the double bond of which may be substituted with a methyl group;
a nitrogen-containing organic compound which is a nitrogen-containing heterocyclic compound or a tertiary amine;
A solvent;
Including ,
a composition in which the nitrogen-containing heterocyclic compound is pyridine, N-methylpyrrolidone, quinoline, piperazine, piperidine, morpholine, carbazole, or triazine, the tertiary amine is represented by N(R ¹ )(R ² )(R ³ ), where R ¹ , R ² , and R ³ are each independently an alkyl group having 1 to 10 carbon atoms which may be substituted with a substituent, and when substituted with a substituent, the substituent is each independently -OCOR ^b (wherein each R ^b is independently an alkenyl group having 2 to 10 carbon atoms which may be substituted with a methyl group at the α-position of the double bond);
A composition, wherein the solvent consists essentially of other monomers having ethylenically unsaturated bond groups and/or an organic solvent, with the proviso that the organic solvent does not contain alcohol. The composition according to claim 7 , wherein the proportion of the zinc carboxylate in the composition is 0.1 mass% or more, and the molar ratio of the nitrogen-containing organic compound to zinc atoms in the zinc carboxylate is 2 moles or more. The composition according to claim 7, wherein the composition has a transmittance of 90% or more when the zinc carboxylate is contained at a concentration of 2.5% by mass. 1. A method for producing an ionomer containing zinc atoms, comprising polymerizing a composition comprising a zinc complex and a solvent, comprising:
The zinc complex is represented by the following general formula (I):

In the formula, each L is independently a ligand which is a nitrogen-containing organic compound, and each R is independently an alkenyl group having 2 to 10 carbon atoms and which may be substituted with a methyl group at the α-position of the double bond, or
The following general formula (II):
Zn(OCOR ^a ) ₂ ...(II)
wherein R ^a 's each independently represent an alkenyl group having 2 to 10 carbon atoms, the α-position of the double bond of which may be substituted with a methyl group; and a nitrogen-containing organic compound in an amount of 2 or more molar equivalents relative to the zinc atom of the zinc carboxylate,
the nitrogen-containing organic compound is a nitrogen-containing heterocyclic compound or a tertiary amine,
the nitrogen-containing heterocyclic compound is pyridine, N-methylpyrrolidone, quinoline, piperazine, piperidine, morpholine, carbazole, or triazine, the tertiary amine is represented by N(R ¹ )(R ² )(R ³ ), in which R ¹ , R ² , and R ³ each independently represent an alkyl group having 1 to 10 carbon atoms which may be substituted with a substituent, and when substituted with a substituent, the substituent is each independently -OCOR ^b (wherein each R ^b is independently an alkenyl group having 2 to 10 carbon atoms which may be substituted with a methyl group at the α-position of the double bond);
The method according to claim 1, wherein the solvent consists essentially of other monomers having ethylenically unsaturated bond groups and/or an organic solvent, with the proviso that the organic solvent does not contain alcohol. The following general formula (II):
Zn(OCOR ^a ) ₂ ...(II)
wherein each R ^a is independently an alkenyl group having 2 to 10 carbon atoms, the α-position of the double bond of which may be substituted with a methyl group; a nitrogen-containing organic compound; and a solvent.
the nitrogen-containing organic compound is a nitrogen-containing heterocyclic compound or a tertiary amine,
the nitrogen-containing heterocyclic compound is pyridine, N-methylpyrrolidone, quinoline, piperazine, piperidine, morpholine, carbazole, or triazine, the tertiary amine is represented by N(R ¹ )(R ² )(R ³ ), in which R ¹ , R ² , and R ³ each independently represent an alkyl group having 1 to 10 carbon atoms which may be substituted with a substituent, and when substituted with a substituent, the substituent is each independently -OCOR ^b (wherein each R ^b is independently an alkenyl group having 2 to 10 carbon atoms which may be substituted with a methyl group at the α-position of the double bond);
A method for producing an ionomer containing zinc atoms, comprising polymerizing a composition, wherein the solvent consists essentially of other monomers having ethylenically unsaturated bond groups and/or an organic solvent, with the proviso that the organic solvent does not contain alcohol. The following general formula (II):
Zn(OCOR ^a ) ₂ ...(II)
In the formula, each Ra is independently an alkenyl group having 2 to 10 carbon atoms, the α-position of the double bond of which may be substituted with a methyl group;
a nitrogen-containing organic compound in an amount of 2 or more molar equivalents relative to the zinc atom of the zinc carboxylate;
and
the nitrogen-containing organic compound is a nitrogen-containing heterocyclic compound or a tertiary amine,
A zinc complex, wherein when the nitrogen-containing organic compound is a nitrogen-containing heterocyclic compound, the nitrogen-containing heterocyclic compound does not have a pyridine skeleton, when the nitrogen-containing organic compound is a tertiary amine, the tertiary amine is not substituted with an amide, when the tertiary amine is dimethylaminoethyl methacrylate, the α-position is not substituted with a methyl group, and the nitrogen-containing organic compound is not triethylamine ;
A zinc complex having a transmittance of 90% or more in another monomer having an ethylenically unsaturated bond group containing the zinc complex at a concentration of 2.5% by mass, calculated as a zinc salt, or a zinc complex having a transmittance of 90% or more in an organic solvent containing the zinc complex at a concentration of 2.5% by mass, calculated as a zinc salt. A zinc complex;
A solvent;
A composition comprising:
The zinc complex is represented by the following general formula (I):

In the formula, each L is independently a ligand which is a nitrogen-containing organic compound which is a nitrogen-containing heterocyclic compound or a tertiary amine, and each R is independently an alkenyl group having 2 to 10 carbon atoms and which may be substituted with a methyl group at the α-position of the double bond.
or
The following general formula (II):
Zn(OCOR ^a ) ₂ ...(II)
wherein R ^a 's each independently represent an alkenyl group having 2 to 10 carbon atoms, the α-position of the double bond of which may be substituted with a methyl group; and a nitrogen-containing organic compound which is a nitrogen-containing heterocyclic compound or a tertiary amine, in an amount of 2 or more molar equivalents relative to the zinc atom of the zinc carboxylate,
The composition, wherein the solvent is substantially composed of another monomer having an ethylenically unsaturated bond group and/or an organic solvent, provided that the organic solvent does not contain alcohol, and when the zinc complex is contained in a concentration of 2.5 mass% in terms of a zinc salt, the composition has a transmittance of 90% or more . The following general formula (II):
Zn(OCOR ^a ) ₂ ...(II)
In the formula, each R ^a is independently an alkenyl group having 2 to 10 carbon atoms, the α-position of the double bond of which may be substituted with a methyl group;
a nitrogen-containing organic compound which is a nitrogen-containing heterocyclic compound or a tertiary amine;
A solvent;
A composition comprising:
The composition has a transmittance of 90% or more when the solvent is substantially composed of another monomer having an ethylenically unsaturated bond group and/or an organic solvent, provided that the organic solvent does not contain alcohol and contains the zinc carboxylate at a concentration of 2.5 mass% .