JP2019031689A - Acrylic acid-based copolymer and method for producing the same, and water treatment agent - Google Patents

Acrylic acid-based copolymer and method for producing the same, and water treatment agent Download PDF

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JP2019031689A
JP2019031689A JP2018200405A JP2018200405A JP2019031689A JP 2019031689 A JP2019031689 A JP 2019031689A JP 2018200405 A JP2018200405 A JP 2018200405A JP 2018200405 A JP2018200405 A JP 2018200405A JP 2019031689 A JP2019031689 A JP 2019031689A
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正裕 藤原
Masahiro Fujiwara
正裕 藤原
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    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F5/00—Softening water; Preventing scale; Adding scale preventatives or scale removers to water, e.g. adding sequestering agents
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
    • C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
    • C08F220/52—Amides or imides
    • C08F220/54—Amides, e.g. N,N-dimethylacrylamide or N-isopropylacrylamide
    • C08F220/58—Amides, e.g. N,N-dimethylacrylamide or N-isopropylacrylamide containing oxygen in addition to the carbonamido oxygen, e.g. N-methylolacrylamide, N-(meth)acryloylmorpholine
    • C08F220/585—Amides, e.g. N,N-dimethylacrylamide or N-isopropylacrylamide containing oxygen in addition to the carbonamido oxygen, e.g. N-methylolacrylamide, N-(meth)acryloylmorpholine and containing other heteroatoms, e.g. 2-acrylamido-2-methylpropane sulfonic acid [AMPS]
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F5/00—Softening water; Preventing scale; Adding scale preventatives or scale removers to water, e.g. adding sequestering agents
    • C02F5/08—Treatment of water with complexing chemicals or other solubilising agents for softening, scale prevention or scale removal, e.g. adding sequestering agents
    • C02F5/10—Treatment of water with complexing chemicals or other solubilising agents for softening, scale prevention or scale removal, e.g. adding sequestering agents using organic substances
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
    • C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
    • C08F220/04—Acids; Metal salts or ammonium salts thereof
    • C08F220/06—Acrylic acid; Methacrylic acid; Metal salts or ammonium salts thereof
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F19/00—Preventing the formation of deposits or corrosion, e.g. by using filters or scrapers

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Abstract

To provide an acrylic acid-based copolymer (hereinafter, also referred to as "AA-ATBS-based polymer ")suitable as a main component of a water treatment agent excellent in scale formation suppressing effect on calcium phosphate, and a method for producing the acrylic acid-based copolymer.SOLUTION: The acrylic acid-based copolymer comprises a structural unit (x) derived from acrylic acid or its sodium salt, and a structural unit (y) derived from 2-acrylamido-2-methylpropane sulfonic acid or its sodium salt, where a content ratio of the structural unit (x) and the structural unit (y) are 35-90 mass% and 10-65 mass%, respectively when the total of both of the structural units is 100 mass%, and a weight average molecular weight is 2,000-30,000, and a content ratio of the acrylic acid-based copolymer having a molecular weight of 70,000 or more is 0.30 mass% or less based on the total amount of all polymers.SELECTED DRAWING: None

Description

本発明は、リン酸カルシウムに対するスケール形成の抑制効果に優れる水処理剤の主成分として好適なアクリル酸系共重合体（以下、「ＡＡ／ＡＴＢＳ系重合体」ともいう）及びその製造方法に関する。   The present invention relates to an acrylic acid-based copolymer (hereinafter also referred to as “AA / ATBS-based polymer”) suitable as a main component of a water treatment agent having an excellent effect of suppressing scale formation with respect to calcium phosphate, and a method for producing the same.

無機粒子の分散剤、スケールの形成、沈殿又は沈着を抑制する薬剤等の主成分として、アクリル酸又はその塩に由来する構造単位と、２−アクリルアミド−２−メチルプロパンスルホン酸（「アクリルアミド−ｔｅｒｔ−ブチルスルホン酸」ともいう）又はその塩に由来する構造単位とを含む共重合体（ＡＡ／ＡＴＢＳ系重合体）が知られている。
例えば、特許文献１には、水酸化ナトリウムでｐＨ３．５〜６．０に中和したＡＡ／ＡＴＢＳ系重合体が開示されている。特許文献２には、水酸化ナトリウム及び水酸化カルシウムで中和したＡＡ／ＡＴＢＳ系重合体が開示されている。特許文献３には、フェノキシエチルアクリレート等の難水溶性単量体に由来する構造単位を更に含むＡＡ／ＡＴＢＳ系重合体が開示されている。また、特許文献４には、エトキシル化したトリスチリルフェノールメタクリレートに由来する構造単位を更に含むＡＡ／ＡＴＢＳ系重合体が開示されている。 As a main component such as a dispersant for inorganic particles, a drug that suppresses the formation of scale, precipitation or deposition, a structural unit derived from acrylic acid or a salt thereof, and 2-acrylamido-2-methylpropanesulfonic acid (“acrylamide-tert” A copolymer (AA / ATBS polymer) containing a structural unit derived from a salt thereof or a salt thereof is also known.
For example, Patent Document 1 discloses an AA / ATBS polymer neutralized to pH 3.5 to 6.0 with sodium hydroxide. Patent Document 2 discloses an AA / ATBS polymer neutralized with sodium hydroxide and calcium hydroxide. Patent Document 3 discloses an AA / ATBS polymer further comprising a structural unit derived from a poorly water-soluble monomer such as phenoxyethyl acrylate. Patent Document 4 discloses an AA / ATBS polymer further containing a structural unit derived from ethoxylated tristyrylphenol methacrylate.

特表２０００−５０２３９４号公報Special Table 2000-502394 特表平６−５０４９３９号公報JP-T 6-504939 特開２０００−１６９５０８号公報JP 2000-169508 A 特開平１１−１０４４７９号公報JP-A-11-104479

しかしながら、特許文献１〜４に開示されたＡＡ／ＡＴＢＳ系重合体であっても、これらを水処理剤に用いた場合にはその性能が満足されない場合があった。特にリン酸カルシウムスケールの抑制効果という点では十分ではなく、リン酸カルシウムに対してもスケール形成の抑制効果に優れる水処理剤の主成分として好適なアクリル酸系共重合体（ＡＡ／ＡＴＢＳ系重合体）及びその製造方法並びに水処理剤が望まれている。   However, even when the AA / ATBS polymers disclosed in Patent Documents 1 to 4 are used as water treatment agents, their performance may not be satisfied. In particular, the acrylic phosphate copolymer (AA / ATBS polymer) suitable as a main component of the water treatment agent which is not sufficient in terms of the inhibitory effect of calcium phosphate scale and is excellent in the inhibitory effect of scale formation on calcium phosphate and its A manufacturing method and a water treatment agent are desired.

本発明者は、上記した課題を解決すべく鋭意検討を重ねてきた。その結果、従来の方法によりアクリル酸及び２−アクリルアミド−２−メチルプロパンスルホン酸ナトリウムを重合した場合には、少量ながらも高分子量重合体が副生し、この高分子量重合体がスケール形成抑制能を低下させる要因となっている知見を得た。また、本発明者は、係る知見に基づき、高分子量重合体の割合を特定量以下に低減したＡＡ／ＡＴＢＳ系重合体によりリン酸カルシウムスケールに対しても優れたスケール抑制能を示すことを見出し、本発明を完成した。
さらに、上記高分子量重合体の副生に関して、本発明者は、従来の製造方法では、反応液中のナトリウム濃度が反応の進行に伴い変化するため、一定の条件下で重合を継続できないことによるものであるという考えに至った。この考えに基づき、反応液中のナトリウム濃度を一定量に保ちながら重合を行うことにより、上記高分子量重合体の含有量が極めて少ないＡＡ／ＡＴＢＳ系重合体を効率的に製造することが可能であるという知見を見出した。 The inventor has intensively studied to solve the above problems. As a result, when acrylic acid and sodium 2-acrylamido-2-methylpropanesulfonate were polymerized by the conventional method, a small amount of high molecular weight polymer was produced as a by-product, and this high molecular weight polymer was capable of inhibiting scale formation. The knowledge which became the factor which decreases is obtained. Further, based on such knowledge, the present inventor has found that an AA / ATBS polymer in which the ratio of the high molecular weight polymer is reduced to a specific amount or less exhibits an excellent scale inhibiting ability against calcium phosphate scale. Completed the invention.
Furthermore, regarding the by-product of the high-molecular-weight polymer, the present inventor found that the conventional production method changes the sodium concentration in the reaction solution with the progress of the reaction, so that the polymerization cannot be continued under certain conditions. It came to the idea that it is a thing. Based on this idea, it is possible to efficiently produce an AA / ATBS polymer with a very low content of the high molecular weight polymer by carrying out the polymerization while keeping the sodium concentration in the reaction solution at a constant amount. I found that there was.

本発明は、以下に示される。
［１］アクリル酸又はそのナトリウム塩に由来する構造単位（ｘ）と、２−アクリルアミド−２−メチルプロパンスルホン酸又はそのナトリウム塩に由来する構造単位（ｙ）とを含み、上記構造単位（ｘ）及び上記構造単位（ｙ）の含有割合は、両者の合計を１００質量％とした場合に、それぞれ、３５〜９０質量％及び１０〜６５質量％であるアクリル酸系共重合体であって、
重量平均分子量Ｍｗが２０００〜３００００であり、
分子量が７００００以上であるアクリル酸系共重合体の含有割合が、すべての重合体の合計量に対して０．３０質量％以下であるアクリル酸系共重合体。
［２］上記重量平均分子量Ｍｗと数平均分子量Ｍｎとの比である多分散度（Ｍｗ／Ｍｎ）が３．５以下である上記［１］に記載のアクリル酸系共重合体。
［３］上記構造単位（ｘ）が、アクリル酸のナトリウム塩に由来する構造単位であり、上記構造単位（ｙ）が、２−アクリルアミド−２−メチルプロパンスルホン酸のナトリウム塩に由来する構造単位である上記［１］又は［２］に記載のアクリル酸系共重合体。
［４］上記［１］乃至［３］のいずれか一項に記載のアクリル酸系重合体の製造方法であって、
反応器に、アクリル酸又はそのナトリウム塩、及び、２−アクリルアミド−２−メチルプロパンスルホン酸又はそのナトリウム塩からなる単量体を連続的に供給しつつ、該単量体を重合する工程を備えるアクリル酸系共重合体の製造方法。
［５］上記［１］乃至［３］のいずれか一項に記載のアクリル酸系共重合体の製造方法であって、
３基の反応器を連結した製造装置を用い、第１の反応器において、重合開始剤の存在下、アクリル酸又はそのナトリウム塩、及び、２−アクリルアミド−２−メチルプロパンスルホン酸又はそのナトリウム塩からなる単量体を連続的に供給しつつ、該単量体を重合し、次いで、反応液を、上記第１反応器から、該第１反応器に連結された第２の反応器へ移送し、該第２反応器において、上記反応液に含まれる上記単量体の重合を継続した後、反応液を、上記第２反応器から、該第２反応器に連結された第３の反応器へ移送し、該第３反応器において、重合体含有液のｐＨを９以下に調整するアクリル酸系共重合体の製造方法。
［６］上記重合開始剤が過硫酸塩を含む上記［５］に記載のアクリル酸系共重合体の製造方法。
［７］上記第３反応器において、上記重合体含有液のｐＨを３．０〜８．０に調整する上記［５］又は［６］に記載のアクリル酸系共重合体の製造方法。
［８］上記［１］乃至［３］のいずれか一項に記載のアクリル酸系共重合体を含む水処理剤。
［９］上記アクリル酸系共重合体の重量平均分子量Ｍｗが４０００〜２００００であり、
分子量が７００００以上であるアクリル酸系共重合体の含有割合が、すべての重合体の合計量に対して０．０５質量％以下であり、上記重量平均分子量Ｍｗと数平均分子量Ｍｎとの比である多分散度（Ｍｗ／Ｍｎ）が３．５以下である上記［８］に記載の水処理剤。
本明細書において、重合体の重量平均分子量（以下、「Ｍｗ」ともいう）及び数平均分子量（以下、「Ｍｎ」ともいう）は、ゲル・パーミエーションクロマトグラフィー（以下、「ＧＰＣ」ともいう）により測定された標準ポリアクリル酸ナトリウム換算値である。また、「（メタ）アクリル」の記載は、アクリル及びメタクリルを意味する。 The present invention is shown below.
[1] A structural unit (x) derived from acrylic acid or a sodium salt thereof and a structural unit (y) derived from 2-acrylamido-2-methylpropanesulfonic acid or a sodium salt thereof, the structural unit (x ) And the content ratio of the structural unit (y) are acrylic acid copolymers that are 35 to 90% by mass and 10 to 65% by mass, respectively, when the total of both is 100% by mass,
The weight average molecular weight Mw is 2000-30000,
An acrylic acid copolymer in which the content ratio of an acrylic acid copolymer having a molecular weight of 70,000 or more is 0.30% by mass or less based on the total amount of all polymers.
[2] The acrylic acid copolymer according to [1], wherein a polydispersity (Mw / Mn), which is a ratio of the weight average molecular weight Mw to the number average molecular weight Mn, is 3.5 or less.
[3] The structural unit (x) is a structural unit derived from a sodium salt of acrylic acid, and the structural unit (y) is a structural unit derived from a sodium salt of 2-acrylamido-2-methylpropanesulfonic acid. The acrylic acid copolymer according to [1] or [2] above.
[4] A method for producing an acrylic acid polymer according to any one of [1] to [3] above,
A step of polymerizing the monomer while continuously supplying a monomer comprising acrylic acid or a sodium salt thereof and 2-acrylamido-2-methylpropanesulfonic acid or a sodium salt thereof to the reactor; A method for producing an acrylic acid copolymer.
[5] A method for producing an acrylic acid copolymer according to any one of [1] to [3] above,
Using a production apparatus in which three reactors are connected, in the first reactor, in the presence of a polymerization initiator, acrylic acid or a sodium salt thereof, and 2-acrylamido-2-methylpropanesulfonic acid or a sodium salt thereof The monomer is polymerized while continuously supplying the monomer, and then the reaction liquid is transferred from the first reactor to the second reactor connected to the first reactor. In the second reactor, after the polymerization of the monomer contained in the reaction solution is continued, the reaction solution is supplied from the second reactor to the third reaction connected to the second reactor. A method for producing an acrylic acid copolymer, wherein the pH of the polymer-containing liquid is adjusted to 9 or less in the third reactor.
[6] The method for producing an acrylic acid copolymer according to [5], wherein the polymerization initiator includes a persulfate.
[7] The method for producing an acrylic acid copolymer according to [5] or [6] above, wherein the pH of the polymer-containing liquid is adjusted to 3.0 to 8.0 in the third reactor.
[8] A water treatment agent comprising the acrylic acid copolymer according to any one of [1] to [3].
[9] The acrylic acid copolymer has a weight average molecular weight Mw of 4000 to 20000,
The content ratio of the acrylic acid copolymer having a molecular weight of 70,000 or more is 0.05% by mass or less with respect to the total amount of all polymers, and the ratio of the weight average molecular weight Mw to the number average molecular weight Mn is The water treatment agent according to the above [8], wherein the polydispersity (Mw / Mn) is 3.5 or less.
In this specification, the weight average molecular weight (hereinafter also referred to as “Mw”) and the number average molecular weight (hereinafter also referred to as “Mn”) of the polymer are gel permeation chromatography (hereinafter also referred to as “GPC”). It is a standard sodium polyacrylate conversion value measured by the above. The description of “(meth) acryl” means acryl and methacryl.

本発明のアクリル酸系共重合体（ＡＡ／ＡＴＢＳ系重合体）は、より均一な組成であるので、スケールの形成、沈殿又は沈着を抑制する薬剤、無機粒子の分散剤等の主成分として好適である。特に、２種の構造単位（ｘ）及び（ｙ）の含有割合が特定の範囲にあり、また、実質的に、特定の範囲のＭｗを有するアクリル酸系共重合体からなるので、リン酸カルシウムに対するスケール形成の抑制効果に優れる水処理剤の主成分として好適である。また、本発明のアクリル酸系共重合体は、リン酸カルシウム以外のスケール形成抑制剤、無機粒子等の分散剤、界面活性剤、帯電防止剤、洗剤組成物等の構成成分として用いることもできる。
本発明のアクリル酸系共重合体（ＡＡ／ＡＴＢＳ系重合体）の製造方法によれば、分子量が７００００以上であるアクリル酸系共重合体の生成を抑制することができる。
また、本発明の水処理剤は、リン酸カルシウムに対するスケール形成の抑制効果に優れる。 Since the acrylic acid copolymer (AA / ATBS polymer) of the present invention has a more uniform composition, it is suitable as a main component for agents that suppress scale formation, precipitation, or deposition, and as a dispersant for inorganic particles. It is. In particular, the content ratio of the two types of structural units (x) and (y) is in a specific range, and substantially consists of an acrylic acid copolymer having a specific range of Mw. It is suitable as a main component of a water treatment agent that has an excellent effect of suppressing formation. The acrylic acid copolymer of the present invention can also be used as a constituent component of a scale formation inhibitor other than calcium phosphate, a dispersant such as inorganic particles, a surfactant, an antistatic agent, and a detergent composition.
According to the method for producing an acrylic acid copolymer (AA / ATBS polymer) of the present invention, the production of an acrylic acid copolymer having a molecular weight of 70000 or more can be suppressed.
Moreover, the water treatment agent of this invention is excellent in the inhibitory effect of the scale formation with respect to calcium phosphate.

本発明で用いる製造装置を示す模式図である。It is a schematic diagram which shows the manufacturing apparatus used by this invention.

本発明のアクリル酸系共重合体（ＡＡ／ＡＴＢＳ系重合体）は、アクリル酸又はそのナトリウム塩に由来する構造単位（ｘ）と、２−アクリルアミド−２−メチルプロパンスルホン酸又はそのナトリウム塩に由来する構造単位（ｙ）とを含み、上記構造単位（ｘ）及び上記構造単位（ｙ）の含有割合は、両者の合計を１００質量％とした場合に、それぞれ、３５〜９０質量％及び１０〜６５質量％であり、Ｍｗが２０００〜３００００であり、分子量が７００００以上であるアクリル酸系共重合体の含有割合が、すべての重合体の合計量に対して０．３０質量％以下である。   The acrylic acid copolymer (AA / ATBS polymer) of the present invention comprises a structural unit (x) derived from acrylic acid or a sodium salt thereof, and 2-acrylamido-2-methylpropanesulfonic acid or a sodium salt thereof. And the content ratio of the structural unit (x) and the structural unit (y) is 35 to 90% by mass and 10%, respectively, when the total of both is 100% by mass. -65 mass%, Mw is 2000-30000, and the content ratio of the acrylic acid copolymer having a molecular weight of 70000 or more is 0.30 mass% or less with respect to the total amount of all polymers. .

本発明のＡＡ／ＡＴＢＳ系重合体は、これに含まれる構造単位（ｘ）が、アクリル酸に由来する構造単位及びアクリル酸のナトリウム塩に由来する構造単位の少なくとも一方であり、構造単位（ｙ）が、２−アクリルアミド−２−メチルプロパンスルホン酸に由来する構造単位及び２−アクリルアミド−２−メチルプロパンスルホン酸のナトリウム塩に由来する構造単位の少なくとも一方である。特に好ましい態様は、構造単位（ｙ）の少なくとも１つが−ＳＯ３Ｎａを有する重合体である。 In the AA / ATBS polymer of the present invention, the structural unit (x) contained therein is at least one of a structural unit derived from acrylic acid and a structural unit derived from a sodium salt of acrylic acid, and the structural unit (y ) Is at least one of a structural unit derived from 2-acrylamido-2-methylpropanesulfonic acid and a structural unit derived from the sodium salt of 2-acrylamido-2-methylpropanesulfonic acid. A particularly preferred embodiment is a polymer in which at least one of the structural units (y) has —SO 3 Na.

本発明のＡＡ／ＡＴＢＳ系重合体を構成する構造単位（ｘ）及び構造単位（ｙ）の含有割合は、高いリン酸カルシウム析出防止能を得る観点から、両者の合計を１００質量％とした場合に、それぞれ、３５〜９０質量％及び１０〜６５質量％であり、好ましくは４０〜８０質量％及び２０〜６０質量％、より好ましくは４５〜７５質量％及び２５〜５５質量％である。   The content ratio of the structural unit (x) and the structural unit (y) constituting the AA / ATBS-based polymer of the present invention is, from the viewpoint of obtaining high calcium phosphate precipitation preventing ability, when the total of both is 100% by mass, They are 35-90 mass% and 10-65 mass%, respectively, Preferably they are 40-80 mass% and 20-60 mass%, More preferably, they are 45-75 mass% and 25-55 mass%.

本発明のＡＡ／ＡＴＢＳ系重合体が、分子量が７００００以上であるアクリル酸系共重合体を含む場合、その含有割合が、すべての重合体の合計量に対して０．３０質量％以下であり、好ましくは０．１０質量％以下、更に好ましくは０．０５質量％以下である。   When the AA / ATBS polymer of the present invention includes an acrylic acid copolymer having a molecular weight of 70000 or more, the content ratio is 0.30% by mass or less based on the total amount of all the polymers. Preferably, it is 0.10 mass% or less, More preferably, it is 0.05 mass% or less.

本発明のＡＡ／ＡＴＢＳ系重合体のＭｗは、高いリン酸カルシウム析出防止能を得る観点から、２０００〜３００００であり、好ましくは４０００〜２００００である。また、Ｍｗと数平均分子量Ｍｎとの比である多分散度（Ｍｗ／Ｍｎ）は３．８以下であり、好ましくは３．５以下、より好ましくは３．１以下である。但し、下限は、通常、２．０である。   Mw of the AA / ATBS polymer of the present invention is 2000 to 30000, preferably 4000 to 20000 from the viewpoint of obtaining high calcium phosphate precipitation preventing ability. The polydispersity (Mw / Mn), which is the ratio of Mw to the number average molecular weight Mn, is 3.8 or less, preferably 3.5 or less, more preferably 3.1 or less. However, the lower limit is usually 2.0.

本発明のＡＡ／ＡＴＢＳ系重合体の構造は、特に限定されないが、好ましくはランダム共重合体である。
本発明のＡＡ／ＡＴＢＳ系重合体は、アクリル酸又はそのナトリウム塩、及び、２−アクリルアミド−２−メチルプロパンスルホン酸又はそのナトリウム塩からなる単量体を用いて、好ましくは連続重合法により得られたものとすることができる。 The structure of the AA / ATBS polymer of the present invention is not particularly limited, but is preferably a random copolymer.
The AA / ATBS polymer of the present invention is preferably obtained by a continuous polymerization method using a monomer comprising acrylic acid or a sodium salt thereof and 2-acrylamido-2-methylpropanesulfonic acid or a sodium salt thereof. Can be.

本発明におけるＡＡ／ＡＴＢＳ系重合体の製造方法（以下、「本発明の製造方法」という）は、反応器に、アクリル酸又はそのナトリウム塩、及び、２−アクリルアミド−２−メチルプロパンスルホン酸又はそのナトリウム塩からなる単量体を連続的に供給しつつ、これを重合する工程を備えるものである。   In the present invention, a method for producing an AA / ATBS polymer (hereinafter referred to as “the production method of the present invention”) includes acrylic acid or a sodium salt thereof and 2-acrylamido-2-methylpropanesulfonic acid or A step of polymerizing the sodium salt monomer while continuously supplying the monomer is provided.

本発明において、特に好ましい態様のＡＡ／ＡＴＢＳ系重合体を製造する方法は、３基の反応器を連結した製造装置を用い、第１の反応器において、重合開始剤の存在下、アクリル酸又はそのナトリウム塩、及び、２−アクリルアミド−２−メチルプロパンスルホン酸又はそのナトリウム塩からなる単量体を連続的に供給しつつ、単量体を重合し、次いで、反応液（以下、「反応液（Ｓ１）」という）を、第１反応器から、第１反応器に連結された第２の反応器へ移送し、第２反応器において、反応液（Ｓ１）に含まれる単量体の重合を継続した後、反応液（以下、「反応液（Ｓ２）」という）を、第２反応器から、第２反応器に連結された第３の反応器へ移送し、第３反応器において、重合体含有液のｐＨを９以下に調整するというものである。このように、本発明によると、連続槽型重合装置を用いて、単量体の重合、重合体の移液等を連続的に進めることにより、高分子量重合体であるアクリル酸系共重合体の副生を抑制しつつ、Ｍｗが２０００〜３００００であるアクリル酸系共重合体の生成率の高い均一なＡＡ／ＡＴＢＳ系重合体を製造することができる。尚、本発明の製造方法では、第２反応器及び第３反応器において継続される単量体の重合により、実質的に、Ｍｗが２０００〜３００００であるアクリル酸系共重合体又はその前駆体が形成される。   In the present invention, a method for producing an AA / ATBS polymer of a particularly preferred embodiment uses a production apparatus in which three reactors are connected, and acrylic acid or acrylic acid in the presence of a polymerization initiator is used in the first reactor. The monomer was polymerized while continuously supplying the sodium salt and a monomer comprising 2-acrylamido-2-methylpropanesulfonic acid or a sodium salt thereof, and then a reaction solution (hereinafter referred to as “reaction solution”). (S1) ”is transferred from the first reactor to the second reactor connected to the first reactor, and in the second reactor, polymerization of the monomer contained in the reaction liquid (S1) is performed. Then, the reaction solution (hereinafter referred to as “reaction solution (S2)”) is transferred from the second reactor to the third reactor connected to the second reactor, and in the third reactor, The pH of the polymer-containing liquid is adjusted to 9 or less. That. Thus, according to the present invention, by using a continuous tank polymerization apparatus, the polymerization of the monomer, the transfer of the polymer, etc. are continuously advanced, so that the acrylic acid copolymer that is a high molecular weight polymer. A uniform AA / ATBS polymer with a high production rate of an acrylic acid copolymer having an Mw of 2000 to 30000 can be produced. In the production method of the present invention, an acrylic acid copolymer having a Mw of 2000 to 30000 or a precursor thereof is substantially obtained by polymerization of monomers continued in the second reactor and the third reactor. Is formed.

本発明の製造方法で用いる装置は、特に限定されないが、例えば、３基の反応器を備える製造装置の概略図を図１に示す。図１の製造装置（１００）は、原料（１５）を供給する手段、攪拌手段、温度調節手段、還流冷却手段、排出手段等を備える第１反応器（１０）と、原料等（２５）を供給する手段、攪拌手段、温度調節手段、還流冷却手段、排出手段等を備える第２反応器（２０）と、ｐＨ調整剤等（３５）を供給する手段、攪拌手段、温度調節手段、還流冷却手段、排出手段等を備える第３反応器（３０）とを備える。   Although the apparatus used with the manufacturing method of this invention is not specifically limited, For example, the schematic of a manufacturing apparatus provided with three reactors is shown in FIG. The production apparatus (100) of FIG. 1 includes a first reactor (10) having means for supplying a raw material (15), stirring means, temperature adjusting means, reflux cooling means, discharge means, etc., and raw materials (25). Second reactor (20) having means for supplying, stirring means, temperature adjusting means, reflux cooling means, discharge means, etc., means for supplying pH adjusting agent etc. (35), stirring means, temperature adjusting means, reflux cooling And a third reactor (30) provided with means, discharge means and the like.

上記第１反応器（１０）では、アクリル酸又はそのナトリウム塩と、２−アクリルアミド−２−メチルプロパンスルホン酸又はそのナトリウム塩とからなる単量体が連続的に供給され、重合開始剤の存在下に重合される。この単量体は、アクリル酸又は２−アクリルアミド−２−メチルプロパンスルホン酸を含むことが好ましい。また、この反応系では、重合用媒体として水が用いられ、必要に応じて、連鎖移動剤を用いることができる。
上記第１反応器（１０）に供給される単量体を構成するアクリル酸の割合は、好ましくは３５〜９０質量％、より好ましくは４０〜８０質量％、更に好ましくは４５〜７５質量％である。また、上記第１反応器（１０）における単量体の濃度は、重合用媒体を１００質量％とすると、好ましくは２０〜２００質量％、より好ましくは５０〜１５０質量％である。
本発明の製造方法では、分子量分布の狭い重合体を得る観点から、第１反応器（１０）において重合反応の９０％以上を行うことが好ましく、そのためには、用いる単量体の９０質量％以上を第１反応器（１０）に供給することが好適に採用される。更に、９５質量％以上を第１反応器（１０）に供給することがより好ましい。また、第１反応器（１０）では、単量体の重合転換率が９０％以上となるような条件を選択して重合を行うことが好ましい。 In the first reactor (10), a monomer comprising acrylic acid or a sodium salt thereof and 2-acrylamido-2-methylpropanesulfonic acid or a sodium salt thereof is continuously supplied, and the presence of a polymerization initiator is present. Polymerized below. This monomer preferably contains acrylic acid or 2-acrylamido-2-methylpropanesulfonic acid. In this reaction system, water is used as a polymerization medium, and a chain transfer agent can be used as necessary.
The proportion of acrylic acid constituting the monomer supplied to the first reactor (10) is preferably 35 to 90% by mass, more preferably 40 to 80% by mass, and still more preferably 45 to 75% by mass. is there. The concentration of the monomer in the first reactor (10) is preferably 20 to 200% by mass, more preferably 50 to 150% by mass when the polymerization medium is 100% by mass.
In the production method of the present invention, from the viewpoint of obtaining a polymer having a narrow molecular weight distribution, it is preferable to carry out 90% or more of the polymerization reaction in the first reactor (10). Supplying the above to the first reactor (10) is preferably employed. Furthermore, it is more preferable to supply 95 mass% or more to the first reactor (10). In the first reactor (10), it is preferable to carry out the polymerization by selecting conditions such that the polymerization conversion rate of the monomer is 90% or more.

上記重合開始剤としては、過酸化水素；過硫酸ナトリウム、過硫酸カリウム、過硫酸アンモニウム等の過硫酸塩；ジメチル２，２’−アゾビス（２−メチルプロピオネート）、２，２’−アゾビス（イソブチロニトリル）、２，２’−アゾビス（２−メチルブチロニトリル）、２，２’−アゾビス（２，４−ジメチルバレロニトリル）、２，２’−アゾビス（４−メトキシ−２，４−ジメチルバレロニトリル）、２，２’−アゾビス（イソ酪酸）ジメチル、４，４’−アゾビス（４−シアノ吉草酸）、２，２’−アゾビス（２−メチルプロピオンアミジン）二塩酸塩、２，２’−アゾビス［Ｎ−（２−カルボキシエチル）−２−メチルプロピオンアミジン］ｎ水和物、２，２’−アゾビス［２−（２−イミダゾリン−２−イル）プロパン］二塩酸塩、２，２’−アゾビス［２−（２−イミダゾリン−２−イル）プロパン］二硫酸塩二水和物、１，１’−アゾビス（シクロヘキサン−１−カルボニトリル）等のアゾ系化合物；過酸化ベンゾイル、過酸化ラウロイル、過酢酸、ジ−ｔ−ブチルパーオキサイド、クメンヒドロパーオキサイド等の有機過酸化物等が挙げられる。これらは、単独で用いてよいし、２種以上を組み合わせて用いてもよい。本発明では、過硫酸塩を用いることが好ましい。
上記重合開始剤の使用量は、上記単量体１００質量部に対して、好ましくは０．２〜２．０質量部、より好ましくは０．５〜１．５質量部である。 Examples of the polymerization initiator include hydrogen peroxide; persulfates such as sodium persulfate, potassium persulfate, and ammonium persulfate; dimethyl 2,2′-azobis (2-methylpropionate), 2,2′-azobis ( Isobutyronitrile), 2,2′-azobis (2-methylbutyronitrile), 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (4-methoxy-2, 4-dimethylvaleronitrile), 2,2′-azobis (isobutyric acid) dimethyl, 4,4′-azobis (4-cyanovaleric acid), 2,2′-azobis (2-methylpropionamidine) dihydrochloride, 2,2′-azobis [N- (2-carboxyethyl) -2-methylpropionamidine] n hydrate, 2,2′-azobis [2- (2-imidazolin-2-yl) propane] dihydrochloride , 2, 2 Azo compounds such as' -azobis [2- (2-imidazolin-2-yl) propane] disulfate dihydrate, 1,1'-azobis (cyclohexane-1-carbonitrile); benzoyl peroxide, Examples thereof include organic peroxides such as lauroyl oxide, peracetic acid, di-t-butyl peroxide and cumene hydroperoxide. These may be used alone or in combination of two or more. In the present invention, it is preferable to use a persulfate.
The amount of the polymerization initiator used is preferably 0.2 to 2.0 parts by mass, more preferably 0.5 to 1.5 parts by mass with respect to 100 parts by mass of the monomer.

上記連鎖移動剤としては、メルカプトエタノール、チオグリセロール、チオグリコール酸、２−メルカプトプロピオン際、３−メルカプトプロピオン際、チオリンゴ酸、チオグリコール酸オクチル、３−メルカプトプロピオン酸オクチル、２−メルカプトエタンスルホン酸、ｎ−ドデシルメルカプタン、オクチルメルカプタン、ブチルチオグリコレート等の、チオール系連鎖移動剤；亜リン酸、次亜リン酸、及びその塩（次亜リン酸ナトリウム、次亜リン酸カリウム等）や、亜硫酸、亜硫酸水素、亜二チオン酸、メタ重亜硫酸、及びその塩（亜硫酸水素ナトリウム、亜硫酸水素カリウム、亜二チオン酸ナトリウム、亜二チオン酸カリウム、メタ重亜硫酸ナトリウム、メタ重亜硫酸カリウム等）等が挙げられる。これらは、単独で用いてよいし、２種以上を組み合わせて用いてもよい。
上記連鎖移動剤の使用量は、上記単量体１００質量部に対して、好ましくは１〜２０質量部、より好ましくは３〜１０質量部である。 Examples of the chain transfer agent include mercaptoethanol, thioglycerol, thioglycolic acid, 2-mercaptopropion, 3-mercaptopropion, thiomalic acid, octyl thioglycolate, octyl 3-mercaptopropionate, 2-mercaptoethanesulfonic acid Thiol chain transfer agents such as n-dodecyl mercaptan, octyl mercaptan, butyl thioglycolate; phosphorous acid, hypophosphorous acid, and salts thereof (sodium hypophosphite, potassium hypophosphite, etc.), Sulfurous acid, hydrogen sulfite, dithionite, metabisulfite, and salts thereof (sodium hydrogensulfite, potassium hydrogensulfite, sodium dithionite, potassium dithionite, sodium metabisulfite, potassium metabisulfite, etc.), etc. Is mentioned. These may be used alone or in combination of two or more.
The amount of the chain transfer agent used is preferably 1 to 20 parts by mass, more preferably 3 to 10 parts by mass with respect to 100 parts by mass of the monomer.

上記第１反応器（１０）における単量体の重合温度（反応系の温度）は、重合開始剤の種類等により、適宜、選択されるが、円滑に重合が進行することから、好ましくは６０℃〜１００℃、より好ましくは７０℃〜９０℃である。
尚、本発明の製造方法では、連続的に供給される単量体の重合は、第１反応器（１０）においてではなく、第２反応器（２０）又は第３反応器（３０）において完結する。従って、第１反応器（１０）で得られ、第２反応器（２０）に供給される反応液（Ｓ１）には、通常、重合体、単量体、重合開始剤等が含まれる。また、第２反応器（２０）で得られ、第３反応器（３０）に供給される反応液（Ｓ２）において、重合体の他に、単量体、重合開始剤等が含まれ得る。
上記第１反応器（１０）における単量体の平均滞留時間は、好ましくは３０〜３００分間、より好ましくは５０〜２００分間である。 The monomer polymerization temperature (reaction system temperature) in the first reactor (10) is appropriately selected depending on the type of the polymerization initiator and the like, but is preferably 60 because the polymerization proceeds smoothly. ° C to 100 ° C, more preferably 70 ° C to 90 ° C.
In the production method of the present invention, the polymerization of the continuously supplied monomer is completed not in the first reactor (10) but in the second reactor (20) or the third reactor (30). To do. Accordingly, the reaction liquid (S1) obtained in the first reactor (10) and supplied to the second reactor (20) usually contains a polymer, a monomer, a polymerization initiator, and the like. In addition, in the reaction liquid (S2) obtained in the second reactor (20) and supplied to the third reactor (30), in addition to the polymer, a monomer, a polymerization initiator, and the like may be included.
The average residence time of the monomer in the first reactor (10) is preferably 30 to 300 minutes, more preferably 50 to 200 minutes.

次に、第２反応器（２０）において、第１反応器（１０）から送液された反応液（Ｓ１）に残存する単量体の重合が進められる。尚、この第２反応器（２０）で行われる重合は、反応液（Ｓ１）に含まれる単量体のみに対して行われるものであってよいし、必要に応じて、更に供給された単量体とともに行われるものであってもよい。また、上記第２反応器（２０）においては、予め、重合開始剤、重合用媒体等を収容しておいてもよい。
上記第２反応器（２０）における反応系の温度は、好ましくは６０℃〜１００℃、より好ましくは７０℃〜９０℃である。尚、重合温度は、上記第１反応器（１０）における温度と同じであっても、異なってもよい。
上記第２反応器（２０）における単量体の平均滞留時間は、均一な重合体を形成しつつ重合が完結することから、好ましくは２０〜２００分間、より好ましくは３０〜１００分間である。 Next, in the second reactor (20), polymerization of the monomer remaining in the reaction solution (S1) sent from the first reactor (10) is advanced. The polymerization performed in the second reactor (20) may be performed only on the monomer contained in the reaction liquid (S1), and if necessary, the supplied single unit. It may be performed together with the mass. In the second reactor (20), a polymerization initiator, a polymerization medium and the like may be accommodated in advance.
The temperature of the reaction system in the second reactor (20) is preferably 60 ° C to 100 ° C, more preferably 70 ° C to 90 ° C. The polymerization temperature may be the same as or different from the temperature in the first reactor (10).
The average residence time of the monomer in the second reactor (20) is preferably 20 to 200 minutes, more preferably 30 to 100 minutes, since the polymerization is completed while forming a uniform polymer.

その後、第３反応器（３０）において、第２反応器（２０）から送液された反応液（Ｓ２）に残存する単量体の重合、及び、この反応液（Ｓ２）に含まれるアクリル酸系共重合体の前駆体の中和が行われる。上記反応液（Ｓ２）のｐＨは、通常、１．０〜５．０の範囲にあるので、中和には、通常、ナトリウム、カリウム等のアルカリ金属の水酸化物、塩化物又は炭酸塩；カルシウム、マグネシウム等のアルカリ土類金属の水酸化物、塩化物又は炭酸塩；アンモニア；モノエタノールアミン、ジエタノールアミン、トリエタノールアミン等の有機アミン等のアルカリ性物質を、水に溶解させたアルカリ性水溶液が用いられる。上記アルカリ性物質は、単独で用いてよいし、２種以上を組み合わせて用いてもよい。
また、上記第３反応器（３０）においては、予め、重合用媒体等を収容しておいてもよい。 Thereafter, in the third reactor (30), polymerization of monomers remaining in the reaction liquid (S2) sent from the second reactor (20), and acrylic acid contained in the reaction liquid (S2) Neutralization of the precursor of the system copolymer is performed. Since the pH of the reaction solution (S2) is usually in the range of 1.0 to 5.0, neutralization usually involves alkali metal hydroxides such as sodium and potassium, chlorides or carbonates; Alkaline earth metal hydroxides such as calcium and magnesium, chlorides or carbonates; ammonia; alkaline aqueous solutions in which alkaline substances such as organic amines such as monoethanolamine, diethanolamine and triethanolamine are dissolved in water are used It is done. The said alkaline substance may be used independently and may be used in combination of 2 or more type.
In the third reactor (30), a polymerization medium or the like may be stored in advance.

上記第３反応器（３０）における重合体含有液のｐＨは、上記アルカリ性水溶液により、９以下、好ましくは３．０〜８．０の範囲に調整される。
以上の工程により、実質的に、Ｍｗが２０００〜３００００であるアクリル酸系共重合体からなり、固形分濃度が好ましくは３０〜５０質量％である、ＡＡ／ＡＴＢＳ系重合体含有液を得ることができる。重合用媒体が水である場合には、重合体水溶液が得られる。 The pH of the polymer-containing liquid in the third reactor (30) is adjusted to 9 or less, preferably in the range of 3.0 to 8.0, with the alkaline aqueous solution.
By the above steps, an AA / ATBS polymer-containing liquid that substantially consists of an acrylic acid copolymer having a Mw of 2000 to 30000 and has a solid content concentration of preferably 30 to 50% by mass is obtained. Can do. When the polymerization medium is water, an aqueous polymer solution is obtained.

本発明の製造方法によれば、ナトリウム濃度一定の条件下で重合反応を進行させることができる。このため、ナトリウム濃度が変化することによる重合速度の変化等の現象が生じ難く、結果として分子量が７００００を超えるような高分子量重合体の生成を抑えつつ、Ｍｗ２０００〜３００００の均質なＡＡ／ＡＴＢＳ系重合体を得ることができる。   According to the production method of the present invention, the polymerization reaction can proceed under the condition of a constant sodium concentration. Therefore, a phenomenon such as a change in polymerization rate due to a change in sodium concentration hardly occurs, and as a result, a homogeneous AA / ATBS system having a Mw of 2000 to 30000 is suppressed while suppressing the formation of a high molecular weight polymer having a molecular weight exceeding 70000. A polymer can be obtained.

本発明のアクリル酸系共重合体は、リン酸カルシウムに対するスケール形成の抑制効果に優れる水処理剤、リン酸カルシウム以外のスケール形成抑制剤、無機粒子等の分散剤、界面活性剤、帯電防止剤、洗剤組成物等の構成成分として好適である。   The acrylic acid copolymer of the present invention is a water treatment agent having an excellent effect of suppressing scale formation with respect to calcium phosphate, a scale formation inhibitor other than calcium phosphate, a dispersant such as inorganic particles, a surfactant, an antistatic agent, and a detergent composition. It is suitable as a constituent component.

本発明の水処理剤は、上記本発明のＡＡ／ＡＴＢＳ系重合体を含有するものであり、通常、更に水を含む組成物である。ＡＡ／ＡＴＢＳ系重合体の種類は、特に限定されず、１種のみであってよいし、２種以上であってもよい。   The water treatment agent of the present invention contains the AA / ATBS polymer of the present invention, and is usually a composition further containing water. The kind of AA / ATBS polymer is not particularly limited, and may be one kind or two or more kinds.

本発明の水処理剤におけるＡＡ／ＡＴＢＳ系重合体の含有割合は、水処理剤としての効果が十分に得られることから、好ましくは５〜４５質量％、より好ましくは１０〜３５質量％である。   The content ratio of the AA / ATBS polymer in the water treatment agent of the present invention is preferably 5 to 45% by mass, more preferably 10 to 35% by mass, since the effect as the water treatment agent is sufficiently obtained. .

本発明の水処理剤は、必要に応じて、ポリアクリル酸又はその塩、ポリマレイン酸又はその塩、（メタ）アクリル酸系共重合体、スチレン・マレイン酸系共重合体等の他のスケール抑制剤、殺菌剤、防食剤、スライム防止剤、消泡剤等を含有してもよい。   If necessary, the water treatment agent of the present invention can suppress other scales such as polyacrylic acid or a salt thereof, polymaleic acid or a salt thereof, a (meth) acrylic acid copolymer, a styrene / maleic acid copolymer, etc. Agents, bactericides, anticorrosives, antislime agents, antifoaming agents, and the like.

本発明の水処理剤は、例えば、熱交換器の伝熱面、冷却水の配管等に付着しやすいリン酸カルシウム等に対して好適である。従って、本発明の水処理剤を用いることにより、例えば、冷却水系、ボイラー水系、海水淡水化装置等における、熱交換効率の低下、配管の閉塞等の不具合を抑制することができる。   The water treatment agent of the present invention is suitable for, for example, calcium phosphate that easily adheres to the heat transfer surface of a heat exchanger, piping of cooling water, and the like. Therefore, by using the water treatment agent of the present invention, for example, problems such as a decrease in heat exchange efficiency and blockage of piping in a cooling water system, a boiler water system, a seawater desalination apparatus, and the like can be suppressed.

以下、本発明を実施例により具体的に説明する。但し、本発明は、この実施例に何ら限定されるものではない。尚、下記において、部及び％は、特に断らない限り、質量基準である。   Hereinafter, the present invention will be specifically described by way of examples. However, the present invention is not limited to this embodiment. In the following, “part” and “%” are based on mass unless otherwise specified.

１．アクリル酸系共重合体の製造
以下の実施例では、図１に示すように、それぞれ、攪拌機及びコンデンサを備えた３基の反応器（第１反応器１０、第２反応器２０及び第３反応器３０）を、この順に連結した製造装置１００を用いた。 1. Production of Acrylic Acid Copolymer In the following examples, as shown in FIG. 1, three reactors (first reactor 10, second reactor 20 and third reaction) each equipped with a stirrer and a condenser were used. The manufacturing apparatus 100 which connected the container 30) in this order was used.

実施例１（連続重合による製造）
第１反応器（１０）、第２反応器（２０）及び第３反応器（３０）に、水を２１００ｇずつ仕込み、７５℃に保持した。その後、第１反応器（１０）内を撹拌しながら、アクリル酸の６０％水溶液（以下、「６０％ＡＡ」ともいう）を１１．０ｇ／分、２−アクリルアミド−２−メチルプロパンスルホン酸ナトリウムの５０％水溶液（以下、「５０％ＡＴＢＳＮａ」ともいう）を９．０ｇ／分、過硫酸ナトリウムの１５％水溶液（以下、「１５％ＮＰＳ」ともいう）を０．５ｇ／分、次亜リン酸ナトリウムの３０％水溶液（以下、「３０％ＮＨＰ」ともいう）を２．５ｇ／分で供給し、重合を行った。そして、これらの原料（１５）の供給と同時に、第１反応器（１０）内の反応液を、２３．０ｇ／分で第２反応器（２０）へ移液し、第１反応器（１０）内の液量が２１００ｇとなるようにした。尚、第１反応器（１０）における反応液の平均滞留時間を９０分とした。第２反応器（２０）では、第１反応器（１０）からの反応液の供給が始まったと同時に、第２反応器（２０）内の反応液を、２３．０ｇ／分で第３反応器（３０）へ移液した。このように、第２反応器（２０）においても、液量を２１００ｇに保ちながら、撹拌下、重合を継続し、第２反応器（２０）における反応液の平均滞留時間を９０分とした。そして、第３反応器（３０）では、第２反応器（２０）からの反応液（ｐＨ４．０）の供給が始まったと同時に、水及びＮａＯＨの４８％水溶液の供給、並びに、第３反応器（３０）内の反応液の排出及び回収を行った。尚、第３反応器（３０）においても、液量を２１００ｇに保ちながら、撹拌下、中和を継続し、反応液のｐＨが７．０となるようにした。この製造を開始して２４時間経過してから、１時間分の反応液を回収し、固形分濃度が４０％であるアクリル酸系共重合体（Ｅ１）を含み、ｐＨ７．０の重合体水溶液を得た（表１参照）。 Example 1 (Production by continuous polymerization)
The first reactor (10), the second reactor (20), and the third reactor (30) were charged with 2100 g of water and maintained at 75 ° C. Thereafter, while stirring the inside of the first reactor (10), a 60% aqueous solution of acrylic acid (hereinafter also referred to as “60% AA”) was added at 11.0 g / min, sodium 2-acrylamido-2-methylpropanesulfonate. 50% aqueous solution (hereinafter also referred to as “50% ATBSNa”) at 9.0 g / min, sodium persulfate 15% aqueous solution (hereinafter also referred to as “15% NPS”) at 0.5 g / min, hypophosphorous acid Polymerization was carried out by supplying a 30% aqueous solution of sodium acid (hereinafter also referred to as “30% NHP”) at 2.5 g / min. Simultaneously with the supply of these raw materials (15), the reaction liquid in the first reactor (10) is transferred to the second reactor (20) at 23.0 g / min, and the first reactor (10 The amount of liquid in) was 2100 g. The average residence time of the reaction liquid in the first reactor (10) was 90 minutes. In the second reactor (20), the supply of the reaction solution from the first reactor (10) has started, and at the same time, the reaction solution in the second reactor (20) was fed at a rate of 23.0 g / min. The solution was transferred to (30). Thus, also in the 2nd reactor (20), superposition | polymerization was continued under stirring, keeping a liquid quantity at 2100g, and the average residence time of the reaction liquid in the 2nd reactor (20) was 90 minutes. In the third reactor (30), the supply of the reaction solution (pH 4.0) from the second reactor (20) started, and at the same time, the supply of 48% aqueous solution of water and NaOH, and the third reactor The reaction solution in (30) was discharged and collected. In the third reactor (30) as well, while maintaining the liquid volume at 2100 g, neutralization was continued with stirring so that the pH of the reaction liquid became 7.0. After 24 hours from the start of the production, the reaction solution for 1 hour was collected, and an aqueous polymer solution containing an acrylic acid copolymer (E1) having a solid content concentration of 40% and having a pH of 7.0. (See Table 1).

次いで、アクリル酸系共重合体（Ｅ１）を、下記に示す条件でゲルパーミエーションクロマトグラフィー（ＧＰＣ）に供したところ、Ｍｗは８０００、Ｍｗ／Ｍｎは２．８であった。また、分子量分画計算にて求めた分子量７００００以上のアクリル酸系共重合体の含有割合は、アクリル酸系共重合体（Ｅ１）の全体に対して０．０２％であった。
＜ＧＰＣ測定条件＞
装置：東ソー社製ＨＬＣ８０２０システム
検出：ＲＩ
カラム：東ソー社製Ｇ４０００ＰＷｘｌ、Ｇ３０００ＰＷｘｌ及びＧ２５００ＰＷｘｌを連結
溶離液：０．１Ｍ−ＮａＣｌ＋リン酸バッファー（ｐＨ７）
標準：創和科学社製ポリアクリル酸Ｎａ Next, when the acrylic acid copolymer (E1) was subjected to gel permeation chromatography (GPC) under the conditions shown below, Mw was 8000 and Mw / Mn was 2.8. Moreover, the content rate of the acrylic acid type copolymer with a molecular weight of 70000 or more calculated | required by molecular weight fraction calculation was 0.02% with respect to the whole acrylic acid type copolymer (E1).
<GPC measurement conditions>
Apparatus: HLC8020 system manufactured by Tosoh Corporation Detection: RI
Column: Tosoh G4000PWxl, G3000PWxl and G2500PWxl are connected. Eluent: 0.1M NaCl + phosphate buffer (pH 7)
Standard: Polyacrylic acid Na manufactured by Soka Science Co., Ltd.

実施例２（連続重合による製造）
３０％ＮＨＰに代えて、亜硫酸水素ナトリウムの３０％水溶液（以下、「３０％ＮａＨＳＯ３」ともいう）を用いた以外は、実施例１と同様の操作を行い、固形分濃度が４０％であるアクリル酸系共重合体（Ｅ２）を含み、ｐＨ７．０の重合体水溶液を得た（表１参照）。
その後、実施例１と同様にして、アクリル酸系共重合体（Ｅ２）の分析を行い、その結果を表１に併記した。 Example 2 (Production by continuous polymerization)
The same operation as in Example 1 was performed except that a 30% aqueous solution of sodium hydrogen sulfite (hereinafter also referred to as “30% NaHSO 3 ”) was used instead of 30% NHP, and the solid content concentration was 40%. A pH 7.0 aqueous polymer solution containing the acrylic acid copolymer (E2) was obtained (see Table 1).
Thereafter, the acrylic acid copolymer (E2) was analyzed in the same manner as in Example 1, and the results are also shown in Table 1.

実施例３（連続重合による製造）
６０％ＡＡ及び５０％ＡＴＢＳＮａの使用量を変更した以外は、実施例１と同様の操作を行い、固形分濃度が４０％であるアクリル酸系共重合体（Ｅ３）を含み、ｐＨ７．０の重合体水溶液を得た（表１参照）。
その後、実施例１と同様にして、アクリル酸系共重合体（Ｅ３）の分析を行い、その結果を表１に併記した。 Example 3 (Production by continuous polymerization)
Except having changed the usage-amount of 60% AA and 50% ATBSNa, operation similar to Example 1 was performed, and the acrylic acid-type copolymer (E3) whose solid content concentration is 40% is contained, and pH 7.0 is set. A polymer aqueous solution was obtained (see Table 1).
Thereafter, the acrylic acid copolymer (E3) was analyzed in the same manner as in Example 1, and the results are also shown in Table 1.

実施例４（連続重合による製造）
６０％ＡＡ及び５０％ＡＴＢＳＮａの使用量を変更した以外は、実施例２と同様の操作を行い、固形分濃度が４０％であるアクリル酸系共重合体（Ｅ４）を含み、ｐＨ７．０の重合体水溶液を得た（表１参照）。
その後、実施例１と同様にして、アクリル酸系共重合体（Ｅ４）の分析を行い、その結果を表１に併記した。 Example 4 (Production by continuous polymerization)
Except having changed the usage-amount of 60% AA and 50% ATBSNa, operation similar to Example 2 was performed, the acrylic acid-type copolymer (E4) whose solid content concentration is 40%, pH 7.0 was included. A polymer aqueous solution was obtained (see Table 1).
Thereafter, the acrylic acid copolymer (E4) was analyzed in the same manner as in Example 1, and the results are also shown in Table 1.

実施例５（連続重合による製造）
６０％ＡＡ及び５０％ＡＴＢＳＮａの使用量を変更した以外は、実施例１と同様の操作を行い、固形分濃度が４０％であるアクリル酸系共重合体（Ｅ５）を含み、ｐＨ７．０の重合体水溶液を得た（表１参照）。
その後、実施例１と同様にして、アクリル酸系共重合体（Ｅ５）の分析を行い、その結果を表１に併記した。 Example 5 (Production by continuous polymerization)
Except having changed the usage-amount of 60% AA and 50% ATBSNa, operation similar to Example 1 was performed, and the acrylic acid-type copolymer (E5) whose solid content concentration is 40% is contained, and pH 7.0 is set. A polymer aqueous solution was obtained (see Table 1).
Thereafter, the acrylic acid copolymer (E5) was analyzed in the same manner as in Example 1, and the results are also shown in Table 1.

実施例６（連続重合による製造）
６０％ＡＡ及び５０％ＡＴＢＳＮａの使用量を変更した以外は、実施例２と同様の操作を行い、固形分濃度が４０％であるアクリル酸系共重合体（Ｅ６）を含み、ｐＨ７．０の重合体水溶液を得た（表１参照）。
その後、実施例１と同様にして、アクリル酸系共重合体（Ｅ６）の分析を行い、その結果を表１に併記した。 Example 6 (Production by continuous polymerization)
Except having changed the usage-amount of 60% AA and 50% ATBSNa, operation similar to Example 2 was performed, the acrylic acid-type copolymer (E6) whose solid content concentration is 40%, pH 7.0 was included. A polymer aqueous solution was obtained (see Table 1).
Thereafter, the acrylic acid copolymer (E6) was analyzed in the same manner as in Example 1, and the results are also shown in Table 1.

実施例７（連続重合による製造）
３０％ＮＨＰの使用量を変更した以外は、実施例１と同様の操作を行い、固形分濃度が４０％であるアクリル酸系共重合体（Ｅ７）を含み、ｐＨ７．０の重合体水溶液を得た（表１参照）。
その後、実施例１と同様にして、アクリル酸系共重合体（Ｅ７）の分析を行い、その結果を表１に併記した。 Example 7 (Production by continuous polymerization)
Except that the amount of 30% NHP used was changed, the same operation as in Example 1 was performed, and an aqueous polymer solution having a pH of 7.0 containing an acrylic acid copolymer (E7) having a solid content concentration of 40% was obtained. Obtained (see Table 1).
Thereafter, the acrylic acid copolymer (E7) was analyzed in the same manner as in Example 1, and the results are also shown in Table 1.

実施例８（連続重合による製造）
３０％ＮａＨＳＯ３の使用量を変更した以外は、実施例２と同様の操作を行い、固形分濃度が４０％であるアクリル酸系共重合体（Ｅ８）を含み、ｐＨ７．０の重合体水溶液を得た（表１参照）。
その後、実施例１と同様にして、アクリル酸系共重合体（Ｅ８）の分析を行い、その結果を表１に併記した。 Example 8 (Production by continuous polymerization)
Except for changing the amount of 30% NaHSO 3 used, the same operation as in Example 2 was performed, and an aqueous polymer solution having a pH of 7.0 containing an acrylic acid copolymer (E8) having a solid content concentration of 40%. (See Table 1).
Thereafter, the acrylic acid copolymer (E8) was analyzed in the same manner as in Example 1, and the results are also shown in Table 1.

実施例９（連続重合による製造）
３０％ＮＨＰの使用量を変更した以外は、実施例１と同様の操作を行い、固形分濃度が４０％であるアクリル酸系共重合体（Ｅ９）を含み、ｐＨ７．０の重合体水溶液を得た（表１参照）。
その後、実施例１と同様にして、アクリル酸系共重合体（Ｅ９）の分析を行い、その結果を表１に併記した。 Example 9 (Production by continuous polymerization)
Except that the amount of 30% NHP used was changed, the same operation as in Example 1 was performed, and an aqueous polymer solution having a pH of 7.0 containing an acrylic acid copolymer (E9) having a solid content concentration of 40% was obtained. Obtained (see Table 1).
Thereafter, the acrylic acid copolymer (E9) was analyzed in the same manner as in Example 1, and the results are also shown in Table 1.

実施例１０（連続重合による製造）
３０％ＮａＨＳＯ３の使用量を変更した以外は、実施例２と同様の操作を行い、固形分濃度が４０％であるアクリル酸系共重合体（Ｅ１０）を含み、ｐＨ７．０の重合体水溶液を得た（表１参照）。
その後、実施例１と同様にして、アクリル酸系共重合体（Ｅ１０）の分析を行い、その結果を表１に併記した。 Example 10 (Production by continuous polymerization)
Except for changing the amount of 30% NaHSO 3 used, the same operation as in Example 2 was performed, and an aqueous polymer solution having a pH of 7.0 containing an acrylic acid copolymer (E10) having a solid content concentration of 40%. (See Table 1).
Thereafter, the acrylic acid copolymer (E10) was analyzed in the same manner as in Example 1, and the results are also shown in Table 1.

実施例１１（連続重合による製造）
５０％ＡＴＢＳＮａの単独使用に代えて、５０％ＡＴＢＳＮａを５．０ｇ／分、及び、５０％ＡＴＢＳを５．０ｇ／分、の併用とした以外は、実施例１と同様の操作を行い、固形分濃度が４０％であるアクリル酸系共重合体（Ｅ１１）を含み、ｐＨ７．０の重合体水溶液を得た（表１参照）。
その後、実施例１と同様にして、アクリル酸系共重合体（Ｅ１１）の分析を行い、その結果を表１に併記した。 Example 11 (Production by continuous polymerization)
The same operation as in Example 1 was carried out except that 50% ATBSNa was used in combination with 5.0 g / min and 50% ATBSNa was used in combination with 5.0 g / min instead of 50% ATBSNa alone. A polymer aqueous solution having a pH of 7.0 containing an acrylic acid copolymer (E11) having a partial concentration of 40% was obtained (see Table 1).
Thereafter, the acrylic acid copolymer (E11) was analyzed in the same manner as in Example 1, and the results are also shown in Table 1.

実施例１２（連続重合による製造）
５０％ＡＴＢＳＮａの単独使用に代えて、５０％ＡＴＢＳＮａを５．０ｇ／分、及び、５０％ＡＴＢＳを５．０ｇ／分、の併用とした以外は、実施例２と同様の操作を行い、固形分濃度が４０％であるアクリル酸系共重合体（Ｅ１２）を含み、ｐＨ７．０の重合体水溶液を得た（表１参照）。
その後、実施例１と同様にして、アクリル酸系共重合体（Ｅ１２）の分析を行い、その結果を表１に併記した。 Example 12 (Production by continuous polymerization)
In place of the single use of 50% ATBSNa, the same operation as in Example 2 was carried out except that 50% ATBSNa was used in combination with 5.0 g / min and 50% ATBSNa was used with 5.0 g / min. A polymer aqueous solution having a pH of 7.0 containing an acrylic acid copolymer (E12) having a partial concentration of 40% was obtained (see Table 1).
Thereafter, the acrylic acid copolymer (E12) was analyzed in the same manner as in Example 1, and the results are also shown in Table 1.

実施例１３（連続重合による製造）
５０％ＡＴＢＳＮａに代えて、５０％ＡＴＢＳを用い、その供給量を８．０ｇ／分とした以外は、実施例１と同様の操作を行い、固形分濃度が４０％であるアクリル酸系共重合体（Ｅ１３）を含み、ｐＨ７．０の重合体水溶液を得た（表１参照）。
その後、実施例１と同様にして、アクリル酸系共重合体（Ｅ１３）の分析を行い、その結果を表１に併記した。 Example 13 (Production by continuous polymerization)
Acrylic acid copolymer having a solid content of 40% was carried out in the same manner as in Example 1 except that 50% ATBS was used in place of 50% ATBSNa and the supply rate was 8.0 g / min. A polymer aqueous solution having a pH of 7.0 containing the coalescence (E13) was obtained (see Table 1).
Thereafter, the acrylic acid copolymer (E13) was analyzed in the same manner as in Example 1, and the results are also shown in Table 1.

実施例１４（連続重合による製造）
５０％ＡＴＢＳＮａに代えて、５０％ＡＴＢＳを用い、その供給量を８．０ｇ／分とした以外は、実施例２と同様の操作を行い、固形分濃度が４０％であるアクリル酸系共重合体（Ｅ１４）を含み、ｐＨ７．０の重合体水溶液を得た（表１参照）。
その後、実施例１と同様にして、アクリル酸系共重合体（Ｅ１４）の分析を行い、その結果を表１に併記した。 Example 14 (Production by continuous polymerization)
Acrylic acid copolymer having a solid content concentration of 40%, except that 50% ATBS is used in place of 50% ATBSNa and the supply amount is 8.0 g / min. A polymer aqueous solution having a pH of 7.0 containing the coalescence (E14) was obtained (see Table 1).
Thereafter, the acrylic acid copolymer (E14) was analyzed in the same manner as in Example 1, and the results are also shown in Table 1.

比較例１（セミバッチ重合による製造）
攪拌機及びコンデンサを備えた反応器に、水２５０ｇを仕込み７５℃に保持した。次に、７０％ＡＡ４７０ｇ及び５０％ＡＴＢＳＮａ４５０ｇの混合液、１５％ＮＰＳ２５ｇ、並びに、３０％次亜リン酸ナトリウム水溶液１００ｇを、それぞれ、３時間かけて反応器に供給し、撹拌下、重合を行った。原料の供給が終了した後、反応系を７５℃に保ったまま、撹拌下、１時間熟成した。そして、ｐＨ３．９の反応液に、水及びＮａＯＨの４８％水溶液を供給し、固形分濃度が４０％であるアクリル酸系共重合体（Ｃ１）を含み、ｐＨ７．０の重合体水溶液を得た。
その後、実施例１と同様にして、アクリル酸系共重合体（Ｃ１）の分析を行ったところ、Ｍｗは１１０００、Ｍｗ／Ｍｎは３．８であった。また、分子量分画計算にて求めた分子量７００００以上のアクリル酸系共重合体の含有割合は、アクリル酸系共重合体（Ｃ１）の全体に対して１．０％であった。 Comparative Example 1 (Production by semi-batch polymerization)
A reactor equipped with a stirrer and a condenser was charged with 250 g of water and maintained at 75 ° C. Next, a mixed solution of 470 g of 70% AA and 450 g of 50% ATBSNa, 25 g of 15% NPS, and 100 g of a 30% aqueous sodium hypophosphite solution were respectively supplied to the reactor over 3 hours, and polymerization was performed with stirring. . After the supply of the raw materials was completed, the reaction system was aged for 1 hour with stirring while maintaining the reaction system at 75 ° C. Then, a 48% aqueous solution of water and NaOH is supplied to the reaction solution having a pH of 3.9, and an acrylic acid copolymer (C1) having a solid content concentration of 40% is contained to obtain a polymer aqueous solution having a pH of 7.0. It was.
Thereafter, the acrylic acid copolymer (C1) was analyzed in the same manner as in Example 1. As a result, Mw was 11000 and Mw / Mn was 3.8. Moreover, the content rate of the acrylic acid type copolymer with a molecular weight of 70000 or more calculated | required by molecular weight fraction calculation was 1.0% with respect to the whole acrylic acid type copolymer (C1).

比較例２（バッチ重合による製造）
３０％ＮＨＰに代えて、３０％ＮａＨＳＯ３を用いた以外は、比較例１と同様の操作を行い、固形分濃度が４０％であるアクリル酸系共重合体（Ｃ２）を含み、ｐＨ７．０の重合体水溶液を得た。
その後、実施例１と同様にして、アクリル酸系共重合体（Ｃ２）の分析を行ったところ、Ｍｗは１２０００、Ｍｗ／Ｍｎは３．８であった。また、分子量分画計算にて求めた分子量７００００以上のアクリル酸系共重合体の含有割合は、アクリル酸系共重合体（Ｃ２）の全体に対して１．０％であった。 Comparative Example 2 (Production by batch polymerization)
The same procedure as in Comparative Example 1 was performed except that 30% NaHSO 3 was used instead of 30% NHP, and the acrylic acid-based copolymer (C2) having a solid content concentration of 40% was contained, and the pH was 7.0. An aqueous polymer solution was obtained.
Thereafter, the acrylic acid copolymer (C2) was analyzed in the same manner as in Example 1. As a result, Mw was 12000 and Mw / Mn was 3.8. Moreover, the content rate of the acrylic acid type copolymer of molecular weight 70000 or more calculated | required by molecular weight fraction calculation was 1.0% with respect to the whole acrylic acid type copolymer (C2).

２．水処理剤の評価
上記の実施例１〜１４及び比較例１〜２で得られた、固形分濃度が４０％であるアクリル酸系共重合体の水溶液を、そのまま、水処理剤とし、リン酸カルシウムに対するスケール形成の抑制効果を、下記に示す方法で確認した。
＜リン酸カルシウムスケール抑制試験＞
アクリル酸系共重合体の水溶液と、リン酸２ナトリウムと、塩化カルシウムとを用い、アクリル酸系共重合体の濃度が３０ｍｇ／Ｌ、リン酸２ナトリウムの濃度が９０ｍｇ／Ｌ、塩化カルシウムの濃度が３７５ｍｇ／Ｌである液１８０ｍＬを調製した。次いで、この液を撹拌しながら、０．２１％炭酸水素ナトリウム水溶液を２０ｍＬ投入し、水酸化ナトリウムでｐＨ８．５に調整した。その後、６０℃で３時間放置した後、析出分を濾別し、濾液中のカルシウム濃度をＥＤＴＡ滴定にて求め、スケール抑制率を算出した。 2. Evaluation of Water Treatment Agent An aqueous solution of an acrylic acid copolymer having a solid content concentration of 40% obtained in Examples 1 to 14 and Comparative Examples 1 and 2 is used as it is as a water treatment agent, and is used for calcium phosphate. The suppression effect of scale formation was confirmed by the method shown below.
<Calcium phosphate scale inhibition test>
Using an acrylic acid copolymer aqueous solution, disodium phosphate and calcium chloride, the acrylic acid copolymer concentration is 30 mg / L, the disodium phosphate concentration is 90 mg / L, and the calcium chloride concentration. A solution (180 mL) having a concentration of 375 mg / L was prepared. Next, while stirring this solution, 20 mL of 0.21% aqueous sodium hydrogen carbonate solution was added, and the pH was adjusted to 8.5 with sodium hydroxide. Then, after leaving at 60 degreeC for 3 hours, the deposit was filtered, the calcium concentration in a filtrate was calculated | required by EDTA titration, and the scale inhibition rate was computed.

比較例１〜２で得られたアクリル酸系共重合体を含む水処理剤の抑制率は、いずれも８１％であった。一方、実施例１〜１４で得られたアクリル酸系共重合体を含む水処理剤によれば、９０〜９９％と高い抑制率であった（表１参照）。   The suppression rate of the water treatment agent containing the acrylic acid copolymer obtained in Comparative Examples 1 and 2 was 81%. On the other hand, according to the water treatment agent containing the acrylic acid-type copolymer obtained in Examples 1-14, it was 90-99% and the suppression rate was high (refer Table 1).

Figure 2019031689
Figure 2019031689

本発明のアクリル酸系共重合体は、リン酸カルシウムに対するスケール形成の抑制効果に優れる水処理剤、リン酸カルシウム以外のスケール形成抑制剤、無機粒子等の分散剤、界面活性剤、帯電防止剤、洗剤組成物等の構成成分として好適である。
本発明の水処理剤は、例えば、熱交換器の伝熱面、冷却水の配管等に付着しやすいリン酸カルシウム等に対して好適である。 The acrylic acid copolymer of the present invention is a water treatment agent having an excellent effect of suppressing scale formation with respect to calcium phosphate, a scale formation inhibitor other than calcium phosphate, a dispersant such as inorganic particles, a surfactant, an antistatic agent, and a detergent composition. It is suitable as a constituent component.
The water treatment agent of the present invention is suitable for, for example, calcium phosphate that easily adheres to the heat transfer surface of a heat exchanger, piping of cooling water, and the like.

Claims (9)

アクリル酸又はそのナトリウム塩に由来する構造単位（ｘ）と、２−アクリルアミド−２−メチルプロパンスルホン酸又はそのナトリウム塩に由来する構造単位（ｙ）とを含み、前記構造単位（ｘ）及び前記構造単位（ｙ）の含有割合は、両者の合計を１００質量％とした場合に、それぞれ、３５〜９０質量％及び１０〜６５質量％であるアクリル酸系共重合体であって、
重量平均分子量Ｍｗが２０００〜３００００であり、
分子量が７００００以上であるアクリル酸系共重合体の含有割合が、すべての重合体の合計量に対して０．３０質量％以下であるアクリル酸系共重合体。 A structural unit (x) derived from acrylic acid or a sodium salt thereof, and a structural unit (y) derived from 2-acrylamido-2-methylpropanesulfonic acid or a sodium salt thereof, the structural unit (x) and the above The content ratio of the structural unit (y) is an acrylic acid copolymer that is 35 to 90% by mass and 10 to 65% by mass, respectively, when the total of both is 100% by mass,
The weight average molecular weight Mw is 2000-30000,
An acrylic acid copolymer in which the content ratio of an acrylic acid copolymer having a molecular weight of 70,000 or more is 0.30% by mass or less based on the total amount of all polymers. 前記重量平均分子量Ｍｗと数平均分子量Ｍｎとの比である多分散度（Ｍｗ／Ｍｎ）が３．５以下である請求項１に記載のアクリル酸系共重合体。   The acrylic acid copolymer according to claim 1, wherein a polydispersity (Mw / Mn), which is a ratio between the weight average molecular weight Mw and the number average molecular weight Mn, is 3.5 or less. 前記構造単位（ｘ）が、アクリル酸のナトリウム塩に由来する構造単位であり、前記構造単位（ｙ）が、２−アクリルアミド−２−メチルプロパンスルホン酸のナトリウム塩に由来する構造単位である請求項１又は２に記載のアクリル酸系共重合体。   The structural unit (x) is a structural unit derived from a sodium salt of acrylic acid, and the structural unit (y) is a structural unit derived from a sodium salt of 2-acrylamido-2-methylpropanesulfonic acid. Item 3. The acrylic acid copolymer according to item 1 or 2. 請求項１乃至３のいずれか一項に記載のアクリル酸系共重合体の製造方法であって、
反応器に、アクリル酸又はそのナトリウム塩、及び、２−アクリルアミド−２−メチルプロパンスルホン酸又はそのナトリウム塩からなる単量体を連続的に供給しつつ、該単量体を重合する工程を備えるアクリル酸系共重合体の製造方法。 A method for producing the acrylic acid copolymer according to any one of claims 1 to 3,
A step of polymerizing the monomer while continuously supplying a monomer comprising acrylic acid or a sodium salt thereof and 2-acrylamido-2-methylpropanesulfonic acid or a sodium salt thereof to the reactor; A method for producing an acrylic acid copolymer. 請求項１乃至３のいずれか一項に記載のアクリル酸系共重合体の製造方法であって、
３基の反応器を連結した製造装置を用い、第１の反応器において、重合開始剤の存在下、アクリル酸又はそのナトリウム塩、及び、２−アクリルアミド−２−メチルプロパンスルホン酸又はそのナトリウム塩からなる単量体を連続的に供給しつつ、該単量体を重合し、次いで、反応液を、前記第１反応器から、該第１反応器に連結された第２の反応器へ移送し、該第２反応器において、前記反応液に含まれる前記単量体の重合を継続した後、反応液を、前記第２反応器から、該第２反応器に連結された第３の反応器へ移送し、該第３反応器において、重合体含有液のｐＨを９以下に調整するアクリル酸系共重合体の製造方法。 A method for producing the acrylic acid copolymer according to any one of claims 1 to 3,
Using a production apparatus in which three reactors are connected, in the first reactor, in the presence of a polymerization initiator, acrylic acid or a sodium salt thereof, and 2-acrylamido-2-methylpropanesulfonic acid or a sodium salt thereof The monomer is polymerized while continuously supplying the monomer, and then the reaction liquid is transferred from the first reactor to the second reactor connected to the first reactor. In the second reactor, after the polymerization of the monomer contained in the reaction solution is continued, the reaction solution is transferred from the second reactor to the second reaction device connected to the second reactor. A method for producing an acrylic acid copolymer, wherein the pH of the polymer-containing liquid is adjusted to 9 or less in the third reactor. 前記重合開始剤が過硫酸塩を含む請求項５に記載のアクリル酸系共重合体の製造方法。   The method for producing an acrylic acid copolymer according to claim 5, wherein the polymerization initiator contains a persulfate. 前記第３反応器において、前記重合体含有液のｐＨを３．０〜８．０に調整する請求項５又は６に記載のアクリル酸系共重合体の製造方法。   The method for producing an acrylic acid copolymer according to claim 5 or 6, wherein the pH of the polymer-containing liquid is adjusted to 3.0 to 8.0 in the third reactor. 請求項１乃至３のいずれか一項に記載のアクリル酸系共重合体を含む水処理剤。   The water treatment agent containing the acrylic acid type copolymer as described in any one of Claims 1 thru | or 3. 前記アクリル酸系共重合体の重量平均分子量Ｍｗが４０００〜２００００であり、
分子量が７００００以上であるアクリル酸系共重合体の含有割合が、すべての重合体の合計量に対して０．０５質量％以下であり、前記重量平均分子量Ｍｗと数平均分子量Ｍｎとの比である多分散度（Ｍｗ／Ｍｎ）が３．５以下である請求項８に記載の水処理剤。 The acrylic acid copolymer has a weight average molecular weight Mw of 4000 to 20000,
The content ratio of the acrylic acid copolymer having a molecular weight of 70,000 or more is 0.05% by mass or less with respect to the total amount of all the polymers, and the ratio of the weight average molecular weight Mw to the number average molecular weight Mn is The water treatment agent according to claim 8, wherein a certain degree of polydispersity (Mw / Mn) is 3.5 or less.
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