Polymers and methods of making the same

Abstract

The present invention provides a novel polyvinylphosphonic acid-based polymer and a method capable of easily and with high conversion ratio producing the polymer. The production method of the polymer of the present invention includes a polymerization step of polymerizing a compound represented by the following formula (1) in the presence of a radical polymerization initiator and a divalent cation, the polymer having a structural unit represented by the following formula (2). [In formula (1), R 1 represents a substituted or unsubstituted alkoxy group having 1 to 10 carbon atoms]. [In formula (2), R 1 has the same meaning as the above R 1 ].

Description

Technical Field

[0001] This invention relates to a polymer and a method for manufacturing the same. Background Technology

[0002] Polyvinylphosphonate dimethyl ester and other polyvinylphosphonate diesters or polyvinylphosphonic acids are used as polymer electrolyte materials for fuel cells, halogen-free flame retardants, metal surface treatment agents, biocompatible materials, food packaging materials, etc., and their applications have expanded to multiple aspects (Patent Documents 1-3).

[0003] On the other hand, since phosphonate bonds are easily hydrolyzed, it is much more difficult to manufacture vinyl phosphonate monoesters with a structure in which only one of the -OH atoms bonded to the phosphorus atom is esterified compared to vinyl phosphonate diesters. Only recently have efficient manufacturing methods for vinyl phosphonate monoesters been reported (Patent Document 4).

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent No. 6524074

[0007] Patent Document 2: Japanese Patent No. 7075583

[0008] Patent Document 3: WO2020 / 129875

[0009] Patent Document 4: WO2023 / 054663 Summary of the Invention

[0010] The objective of this invention is to provide a novel polyvinylphosphonic acid polymer and a method for manufacturing the polymer easily and with high conversion rates.

[0011] Through dedicated research, the inventors discovered that although divalent cations hardly improve the conversion rate in the polymerization of vinylphosphonic acid or dimethyl vinylphosphonate, the polymerization reaction can be carried out easily and with high conversion rate when divalent cations coexist with free radical polymerization initiators in vinylphosphonic acid monoesters with a specific structure, thus completing the present invention.

[0012] That is, the present invention provides the following <1> to <8>.

[0013] <1> A method for manufacturing a polymer (hereinafter also referred to as "the polymer manufacturing method of the present invention") includes a polymerization step of polymerizing a compound represented by the following formula (1) (hereinafter also referred to as "monomer (1)") in the presence of a free radical polymerization initiator and a divalent cation, wherein the polymer has a structural unit represented by the following formula (2) (hereinafter also referred to as "structural unit (2)").

[0014]

[0015] In equation (1), R 1 [Indicates alkoxy groups with 1 to 10 carbon atoms, whether substituted or unsubstituted]

[0016]

[0017] In equation (2), R 1 With the above R 1 [Same meaning]

[0018] <2> The manufacturing method as described in <1>, wherein the amount of the compound represented by the above formula (1) is 100 mol% relative to the total amount of monomers used in the polymerization process, and the polymer is polyvinylphosphonic acid monoester.

[0019] <3> The manufacturing method as described in <1> or <2>, wherein the above-mentioned divalent cation is a divalent alkaline earth metal ion.

[0020] <4> The manufacturing method as described in any one of <1> to <3>, wherein the amount of the divalent cation used is in the range of 35 moles or more and 85 moles or less relative to the total amount of monomers used in the polymerization process (100 moles).

[0021] <5> The manufacturing method as described in any one of <1> to <4>, wherein R 1 It is an alkoxy group with 1 to 4 carbon atoms, either substituted or unsubstituted.

[0022] <6> The manufacturing method as described in any one of <1> to <5>, wherein the above-described polymerization step is carried out in a solvent containing one or more selected from water and carboxylic anhydrides.

[0023] <7> A polymer (hereinafter also referred to as "the polymer of the present invention") having structural unit (2).

[0024] <8> The polymer as described in <7>, wherein the content of structural unit (2) is 90 to 100 mol% relative to 100 mol% of all structural units contained in the polymer.

[0025] According to the polymer manufacturing method of the present invention, polymers having structural units (2) derived from vinylphosphonic acid monoester can be manufactured easily and with high conversion rates. Attached Figure Description

[0026] Figure 1 It represents polyvinylphosphonic acid monomethyl ester. 1 The 1H-NMR spectrum.

[0027] Figure 2 It represents polyvinylphosphonic acid monomethyl ester. 31 The p-NMR spectrum. Detailed Implementation

[0028] <Polymer Manufacturing Methods>

[0029] The polymer manufacturing method of the present invention is a polymer manufacturing method comprising a polymerization step of polymerizing a monomer (1) in the presence of a free radical polymerization initiator and a divalent cation, wherein the polymer has structural units (2).

[0030] In equations (1) and (2), R 1 The alkoxy group shown preferably has 1 to 8 carbon atoms, more preferably 1 to 6, even more preferably 1 to 4, and particularly preferably 1 to 2. Furthermore, the alkoxy group can be linear or branched. Specifically, examples include methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, tert-butoxy, n-pentoxy, and n-hexoxy.

[0031] R 1 The alkoxy group shown may or may not have substituents. Examples of substituents include halogen atoms such as chlorine, bromine, and fluorine. It should be noted that the substitution position and number of substituents are arbitrary, and when there are two or more substituents, the substituents may be the same or different.

[0032] Examples of monomers (1) include vinylphosphonate monomethyl ester, vinylphosphonate monoethyl ester, vinylphosphonate monopropyl ester, vinylphosphonate monoisopropyl ester, and vinylphosphonate monobutyl ester. One of these monomers may be used alone or in combination of two or more.

[0033] Among these, from the viewpoint of monomer solubility or polymerization reactivity, vinylphosphonate monomethyl ester and vinylphosphonate monoethyl ester are preferred.

[0034] The amount of monomer (1) used is 100 mol% relative to the total amount of monomer used in the polymerization process, preferably 70 to 100 mol%, more preferably 80 to 100 mol%, even more preferably 90 to 100 mol%, even more preferably 95 to 100 mol%, and particularly preferably 100 mol%.

[0035] In the above polymerization process, monomers other than monomer (1) (hereinafter also referred to as "other monomers") may be copolymerized with monomer (1). Examples of other monomers include vinylphosphonic acid; vinylphosphonic acid diesters such as dimethyl vinylphosphonate, diethyl vinylphosphonate, dipropyl vinylphosphonate, and diisopropyl vinylphosphonate; unsaturated carboxylic acid monomers such as acrylic acid and methacrylic acid; unsaturated dicarboxylic acid monomers such as fumaric acid, maleic acid, and itaconic acid; unsaturated dicarboxylic acid anhydride monomers such as maleic anhydride and itaconic anhydride; (meth)acrylate monomers such as methyl acrylate and methyl methacrylate; (meth)acrylamide monomers such as acrylamide and methacrylamide; aromatic vinyl monomers such as styrene and α-methylstyrene; and carboxylic acid vinyl ester monomers such as vinyl acetate. Other monomers may be used alone or in combination of two or more.

[0036] Examples of divalent cations include Ca. 2+ Mg 2+ Be 2+ 、Sr 2+ Ba 2+ Divalent alkaline earth metal ions; Ni 2+ Cu 2+ Mn 2+ Fe 2+ Co 2+ Pt 2+ Divalent transition metal ions; Zn 2+ Pb 2+ Examples include divalent group 12-14 metal ions. A single divalent cation can be used alone, or in combination of two or more.

[0037] Among these, considering the improvement of conversion rate or polymerization rate, and the increase of molecular weight, divalent alkaline earth metal ions are preferred, and Ca is more preferred. 2+ Mg 2+ Ca is particularly preferred. 2+ .

[0038] To polymerize in the presence of divalent cations, simply add a salt of a divalent cation and anion to the system. Examples of such anions include chloride ions, bromide ions, iodide ions, and other halide ions.

[0039] From the perspective of increasing conversion rate or polymerization rate, and increasing molecular weight, salts of divalent alkaline earth metal ions and halide ions are preferred as salts of divalent cations and anions. Examples include CaCl2, CaBr2, CaI2, MgCl2, MgBr2, MgI2, SrCl2, SrBr2, SrI2, BaCl2, BaBr2, and BaI2.

[0040] It should be noted that salts of divalent cations and anions can be used alone or in combination of two or more.

[0041] From the viewpoint of improving conversion rate or polymerization rate, and increasing molecular weight, the amount of divalent cation used is preferably 10 moles or more, more preferably 20 moles or more, further preferably 35 moles or more, and particularly preferably 45 moles or more, relative to the total amount of monomer used in the polymerization process of 100 moles. Furthermore, from the viewpoint of improving conversion rate or polymerization rate, and increasing molecular weight, the amount of divalent cation used is preferably 110 moles or less, more preferably 85 moles or less, and particularly preferably 65 moles or less, relative to the total amount of monomer used in the polymerization process of 100 moles. Specifically, relative to the total amount of monomer used in the polymerization process of 100 moles, it is preferably in the range of 10 moles or more and 110 moles or less, more preferably 20 moles or more and 110 moles or less, further preferably 35 moles or more and 85 moles or less, and particularly preferably 45 moles or more and 65 moles or less.

[0042] When the amount of divalent cation used is 35 moles or more or 45 moles or more relative to the total amount of monomer used in the polymerization process, or 85 moles or less or 65 moles or less relative to the total amount of monomer used in the polymerization process, the conversion rate or polymerization rate is particularly improved. In addition, the molecular weight is also more easily increased.

[0043] The free radical polymerization initiator used in the polymer manufacturing method of the present invention can be any initiator used for free radical polymerization reaction, preferably an organic peroxide initiator or an organic azo compound initiator.

[0044] Examples of organic peroxide-based initiators include peroxide ketones such as methyl ethyl ketone peroxide; diacyl peroxides such as dilauroyl peroxide; dialkyl peroxides such as di-tert-butyl peroxide; peroxide ketals; peroxide alkyl esters; and peroxide carbonates. Examples of organic azo compound-based initiators include azomides; azoimidazolines; azonitrs such as 4,4'-azobis(4-cyanopentanoic acid); azo esters; and azoamides such as 2,2'-azobis[2-methyl-N-(2-hydroxyethyl)propionamide].

[0045] From the viewpoint of the reactivity of the polymerization reaction, organic azo compound initiators are preferred among free radical polymerization initiators, and water-soluble organic azo compound initiators are more preferred.

[0046] From the viewpoint of the reactivity of the polymerization reaction, 2,2'-azobis(2-methylpropanediamine) dihydrochloride, 2,2'-azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride, 2,2'-azobis[2-(2-imidazolin-2-yl)propane] disulfate dihydrate, 2,2'-azobis[2-(2-imidazolin-2-yl)propane], and 2,2'-azobis[N-(2-carboxyethyl)-2-methylpropanediamine] n-hydrate are preferred as water-soluble organic azo compound initiators, especially 2,2'-azobis(2-methylpropanediamine) dihydrochloride.

[0047] Free radical polymerization initiators can be used alone or in combination of two or more.

[0048] From the perspective of the reactivity of the polymerization reaction, the amount of free radical polymerization initiator used is usually about 0.01 to 25 moles relative to the total amount of monomers used in the polymerization process (100 moles), preferably in the range of 0.05 to 5 moles.

[0049] From the viewpoint of the reactivity of the polymerization reaction, the polymerization process is preferably carried out in a solvent, more preferably in a solvent containing one or more of a mixture of water and carboxylic anhydrides, and particularly preferably in a solvent containing water (aqueous solvent).

[0050] Examples of aqueous solvents include water and mixtures of water and organic solvents. The organic solvent used as the aqueous solvent is preferably a monohydric lower alcohol such as ethanol, propanol, or isopropanol (preferably a monohydric alcohol with 1 to 4 carbon atoms). From the viewpoint of the reactivity of the polymerization reaction, the water content relative to the total mass of the aqueous solvent is preferably 80 to 100% by mass, more preferably 90 to 100% by mass, and particularly preferably 99 to 100% by mass. Among such aqueous solvents, water is particularly preferred from the viewpoint of the reactivity of the polymerization reaction.

[0051] Examples of carboxylic anhydrides include acetic anhydride, propionic anhydride, oxalic anhydride, succinic anhydride, maleic anhydride, phthalic anhydride, and benzoic anhydride.

[0052] Examples of solvents containing carboxylic anhydrides include carboxylic anhydrides and mixtures of carboxylic anhydrides and organic solvents. Examples of organic solvents used as solvents containing carboxylic anhydrides include ester solvents such as ethyl acetate and butyl acetate; ether solvents such as diethyl ether, dipropyl ether, methyl-tert-butyl ether, ethyl-tert-butyl ether, dibutyl ether, diisopentyl ether, hexyl methyl ether, octyl methyl ether, cyclopentyl methyl ether, and dicyclopentyl ether; and hydrocarbon solvents such as hexane, heptane, octane, cyclohexane, and toluene.

[0053] Solvents can be used alone or in combination of two or more.

[0054] From the viewpoint of the reactivity of the polymerization reaction, the amount of solvent used is preferably 50 parts by mass or more, more preferably 100 parts by mass or more, and particularly preferably 150 parts by mass or more, relative to 100 parts by mass of the total monomer used in the polymerization process. Furthermore, from the viewpoint of the reactivity of the polymerization reaction, the amount of solvent used is preferably 1250 parts by mass or less, more preferably 1000 parts by mass or less, and particularly preferably 750 parts by mass or less, relative to 100 parts by mass of the total monomer used in the polymerization process. Specifically, relative to 100 parts by mass of the total monomer used in the polymerization process, it is preferably 50 parts by mass or more and 1250 parts by mass or less, more preferably 100 parts by mass or more and 1000 parts by mass or less, and particularly preferably 150 parts by mass or more and 750 parts by mass or less.

[0055] Furthermore, the polymerization temperature in the polymerization process can be set according to the type of free radical polymerization initiator. From the viewpoint of the reactivity of the polymerization reaction, it is preferably 20°C or higher, more preferably 30°C or higher, particularly preferably 40°C or higher, and preferably 100°C or lower, more preferably 90°C or lower, particularly preferably 75°C or lower. As a specific range, it is preferably 20°C or higher and 100°C or lower, more preferably 30°C or higher and 90°C or lower, and particularly preferably 40°C or higher and 75°C or lower.

[0056] The pH value of the polymerization process is usually in the range of 7 to 11, but from the viewpoint of increasing conversion rate or polymerization rate, increasing molecular weight, etc., it is preferably in the range of 7 to 9, more preferably in the range of 7.5 to 8.5, and particularly preferably in the range of 7.5 to 8.

[0057] When the pH value of the polymerization process is kept within this range, the conversion rate or polymerization rate is particularly improved.

[0058] The polymerization time is typically 30 minutes to 72 hours, preferably 1 to 48 hours, and more preferably 2 to 36 hours.

[0059] The polymerization process can be carried out using either batch or continuous methods. For example, specific methods for the polymerization process include: adding monomers, salts of divalent cations and anions, free radical polymerization initiators, and solvents to a reaction vessel and then heating it to initiate polymerization; or heating a reaction vessel pre-filled with monomers, salts of divalent cations and anions, and solvents, and then sequentially adding free radical polymerization initiators to it, thereby inducing polymerization.

[0060] In addition to the polymerization step described above, the polymer manufacturing method of the present invention may also include a purification step of purifying the polymer from the polymer-containing liquid obtained from the polymerization step. The specific purification method is not particularly limited, but separation and purification are preferably carried out by vacuum distillation, reprecipitation purification using a poor solvent, or recrystallization.

[0061] Furthermore, according to the polymer manufacturing method of the present invention, polymers having structural units (2) derived from vinylphosphonic acid monoesters can be manufactured easily and with high conversion rates. The reason for such an effect is not necessarily clear, but the inventors speculate that it is because by carrying out free radical polymerization of monomers (1) in the presence of divalent cations, the divalent cations crosslink the oxygen atoms of the two monomers (1), thereby bringing the intermolecular distance between the two monomers (1) closer and promoting free radical polymerization.

[0062] Furthermore, the polymer of the present invention manufactured in this manner has structural units (2) derived from vinylphosphonic acid monoester, and as a result, it is useful as, for example, a polymer electrolyte material for fuel cells, a halogen-free flame retardant, a metal surface treatment agent, a biocompatible material, a food packaging material, etc. In addition, since it is easier to disperse or dissolve in hydrophobic solvents compared to polyvinylphosphonic acid, it is expected to have applications in a wide range of fields. Furthermore, the polymer of the present invention has higher manufacturing efficiency compared to polyvinylphosphonic acid diester.

[0063] The content of structural unit (2) is 70-100 mol% relative to all structural units contained in the polymer, preferably 80-100 mol%, more preferably 90-100 mol%, even more preferably 95-100 mol%, and particularly preferably 100 mol%. The polymer of the present invention is preferably polyvinylphosphonic acid monoester.

[0064] The polymer of the present invention is preferably a polymer (linear polymer compound) having a one-dimensional structure.

[0065] Furthermore, the polymer of the present invention is preferably a water-soluble polymer. It should be noted that, in this specification, a polymer is water-soluble when it becomes transparent to the naked eye after 10 parts by weight of the polymer is added to 90 parts by weight of water (25°C) and mixed.

[0066] Furthermore, the number-average molecular weight (Mn) of the polymer of the present invention is preferably in the range of 3,000 to 100,000, more preferably in the range of 4,000 to 50,000, and particularly preferably in the range of 5,000 to 30,000.

[0067] In addition, the molecular weight distribution (Mw / Mn) is preferably in the range of 1.0 to 3.0, and more preferably in the range of 1.0 to 2.0.

[0068] In this specification, number-average molecular weight (Mn) and molecular weight distribution (Mw / Mn) refer to values ​​measured by gel permeation chromatography (GPC). Specifically, they can be determined by the methods described in the examples below.

[0069] Example

[0070] The present invention will be described in detail below with reference to specific embodiments, but the present invention is not limited to these embodiments. The analytical conditions in the embodiments are shown below.

[0071] [Identification and Conversion Rate Determination]

[0072] In the identification of chemical structures and determination of conversion rates, the following methods are used: 1 H-NMR (Apparatus: JNM-ECX500II (manufactured by JEOL), 500 MHz, solvent: heavy water) 31 P-NMR (Apparatus: JNM-ECX500II (manufactured by JEOL), 202 MHz, solvent: heavy water, internal standard: H3PO4). The monomer conversion was calculated by measuring the amount of monomer consumed.

[0073] [Molecular weight determination]

[0074] The average molecular weight of the polymer was determined using gel permeation chromatography (GPC) under the following conditions.

[0075] (Conditions for determining average molecular weight)

[0076] Pillars: 2 TSK-gel α-M (manufactured by Tosoh Corporation)

[0077] Solvent: Phosphate buffer (pH=7) (100mM sodium chloride, 25mM sodium dihydrogen phosphate, 25mM sodium phosphate)

[0078] Measurement temperature: 40℃

[0079] Flow rate: 1.0 mL / min

[0080] Standard curve: Standard polyethylene glycol / polyoxyethylene standard

[0081] <Example 1>

[0082]

[0083] In a flask, 0.4230 g (0.0035 mol) of vinylphosphonate monomethyl ester (Maruzen Petrochemical, hereinafter also referred to as "P0.5M") as a monomer, 0.2 mol of 2,2'-azobis(2-methylpropanediamine) dihydrochloride (Fujifilm and Koko Pure Chemical Industries, hereinafter also referred to as "AIBA") as an initiator (based on 100 mol of monomer), 0.0775 g (0.0007 mol) of CaCl2 as a catalyst, and deionized water as a solvent (the total content of monomer and CaCl2 is 25% by mass) were added. After stirring until AIBA dissolved, the flask was placed in a water bath preheated to 60°C and heated while stirring for 24 hours. After polymerization was completed, the flask was cooled in an ice bath to stop the polymerization.

[0084] Dialysis tubing (Spectra / Por 6) was prepared using regenerated cellulose with a molecular weight cutoff of 1000 Da. The obtained substance was purified by dialysis in water and identified as polyvinylphosphonic acid monomethyl ester. The conversion rate, Mn, and Mw / Mn of vinylphosphonic acid monomethyl ester were determined. The results are shown in Table 1.

[0085] <Examples 2-6>

[0086] Except for changing the amounts of monomer and CaCl2 used to those shown in Table 1, the same procedures as in Example 1 were performed. The conversion, Mn, and Mw / Mn of vinylphosphonic acid monomethyl ester are shown in Table 1.

[0087] The polyvinylphosphonic acid monomethyl esters obtained in Examples 1-6 (items 1-6 in the figure) were respectively... 1 H-NMR spectra are shown in Figure 1 ,Will 31 The P-NMR spectrum shows that Figure 2 .

[0088] <Comparative Example 1>

[0089] Except for changing the amount of monomer used to 0.5000 g and omitting CaCl2, the same procedures as in Example 1 were performed. The conversion rate, Mn, and Mw / Mn of vinylphosphonic acid monomethyl ester are shown in Table 1.

[0090] [Table 1]

[0091]

[0092] As shown in Table 1, the conversion rate of the polymerization reaction of vinylphosphonic acid monomethyl ester was obtained by Ca... 2+ The polymerization reaction was significantly improved in the presence of [the substance]. Furthermore, an increase in molecular weight (improvement) was also observed.

[0093] <Reference Example 1>

[0094] Add 0.3303 g of vinylphosphonic acid (Maruzen Petrochemical) as monomer, 0.0025 g of AIBA as initiator, 0.1697 g of CaCl2 as catalyst (0.5 mol relative to 1 mol of monomer), and 1.5000 g of deionized water as solvent to a flask. After stirring until AIBA dissolves, place the flask in a water bath preheated to 60°C and heat while stirring for 24 hours. After polymerization is complete, stop the polymerization by cooling the flask with an ice bath.

[0095] The obtained substance was identified as polyvinylphosphonic acid, and the conversion rate of polyvinylphosphonic acid was determined. The results are shown in Table 2.

[0096] <Reference Example 2>

[0097] Add 0.5000 g of vinylphosphonic acid (Maruzen Petrochemical) as a monomer, 0.0025 g of AIBA as an initiator, and 1.5000 g of deionized water as a solvent to a flask. After stirring until the AIBA dissolves, place the flask in a water bath preheated to 60°C and heat while stirring for 24 hours. After polymerization is complete, stop the polymerization by cooling the flask with an ice bath.

[0098] The obtained substance was identified as polyvinylphosphonic acid, and the conversion rate of polyvinylphosphonic acid was determined. The results are shown in Table 2.

[0099] <Reference Example 3>

[0100] Add 0.3552 g of dimethyl vinylphosphonate (Maruzen Petrochemical) as a monomer, 0.0025 g of AIBA as an initiator, 0.1448 g of CaCl2 (0.5 mol relative to 1 mol of monomer) as a catalyst, and 1.500 g of deionized water as a solvent to a flask. After stirring until AIBA dissolves, place the flask in a water bath preheated to 60°C and heat while stirring for 24 hours. After polymerization is complete, stop the polymerization by cooling the flask with an ice bath.

[0101] The obtained substance was identified as dimethyl polyvinylphosphonate, and the conversion rate of dimethyl polyvinylphosphonate was determined. The results are shown in Table 2.

[0102] <Reference Example 4>

[0103] Add 0.5000 g of dimethyl vinylphosphonate (Maruzen Petrochemical) as a monomer, 0.0025 g of AIBA as an initiator, and 1.5000 g of deionized water as a solvent to a flask. Stir until the AIBA dissolves, then place the flask in a water bath preheated to 60°C and heat while stirring for 24 hours. After polymerization is complete, stop the polymerization by cooling the flask with an ice bath.

[0104] The obtained substance was identified as dimethyl polyvinylphosphonate, and the conversion rate of dimethyl polyvinylphosphonate was determined. The results are shown in Table 2.

[0105] [Table 2]

[0106]

[0107] As shown in Table 2, the conversion rates for the polymerization of vinylphosphonic acid or dimethyl vinylphosphonate, even at Ca... 2+ The polymerization reaction proceeded even in the presence of [a certain substance], without any improvement. Furthermore, no increase in molecular weight (improvement) was observed.

Claims

1. A method for manufacturing a polymer, comprising a polymerization step of polymerizing a compound represented by formula (1) in the presence of a free radical polymerization initiator and a divalent cation, said polymer having a structural unit represented by formula (2). ， In equation (1), R 1 This refers to an alkoxy group having 1 to 10 carbon atoms, either substituted or unsubstituted. ， In equation (2), R 1 With the R 1 They have the same meaning.

2. The manufacturing method according to claim 1, wherein, The amount of the compound represented by formula (1) is 100 mol% relative to the total amount of monomers used in the polymerization process, and the polymer is polyvinylphosphonic acid monoester.

3. The manufacturing method according to claim 1 or 2, wherein, The divalent cation is a divalent alkaline earth metal ion.

4. The manufacturing method according to any one of claims 1 to 3, wherein, The amount of the divalent cation used is in the range of 35 moles or more and 85 moles or less relative to the total amount of monomers used in the polymerization process (100 moles).

5. The manufacturing method according to claim 1, wherein, The amount of compound represented by formula (1) used is 100 mol% relative to the total amount of monomers used in the polymerization process. The polymer is polyvinylphosphonic acid monoester, the divalent cation is a divalent alkaline earth metal ion, and the amount of the divalent cation used is in the range of 35 mol or more and 85 mol or less relative to the total amount of monomers used in the polymerization process.

6. The manufacturing method according to any one of claims 1 to 5, wherein, R 1 It is an alkoxy group with 1 to 4 carbon atoms, either substituted or unsubstituted.

7. The manufacturing method according to any one of claims 1 to 6, wherein, The polymerization process is carried out in a solvent containing one or more solvents selected from water and carboxylic anhydrides.

8. A polymer having a structural unit represented by the following formula (2), ， In equation (2), R 1 The alkoxy group represents alkoxy groups with 1 to 10 carbon atoms, whether substituted or unsubstituted.

9. The polymer according to claim 8, wherein, The content of the structural unit represented by formula (2) is 90 to 100 mol% relative to 100 mol% of all structural units contained in the polymer.

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