JP3934489B2 - Method and apparatus for producing (meth) acrylic acid polymer - Google Patents

Description

【００２２】
（但し、式中Ｒ¹は水素又はメチル基を表し、Ｍは水素、一価金属、二価金属、アンモニウム基又は有機アミン基を表す。）で示されるものがある。
【００２３】
また、（メタ）アクリル酸エステルとしては、一般式（２）
【００２４】
【化２】

【００２５】
（但し、式中Ｒ¹は水素又はメチル基を表し、Ｒ²は−ＣＯＯ（Ｒ³Ｏ）_mＲ⁴または−ＣＯＯＲ⁵を表し、Ｒ³Ｏは炭素数２〜４のオキシアルキレン基の１種又は２種以上の混合物を表し、２種以上の場合はブロック状に付加していてもランダム状に付加していてもよく、Ｒ⁴は水素又は炭素数１〜２２、好ましくは１〜１０のアルキル基を表し、ｍはオキシアルキレン基の平均付加モル数であり１〜３００の整数を表し、Ｒ⁵は炭素原子数１〜２２、好ましくは１〜１０のアルキル基を表す。）
本発明で使用する上記一般式（１）で示される単量体としては、アクリル酸、メタクリル酸ならびにこれらの酸の一価金属塩、二価金属塩、アンモニウム塩および有機アミン塩を挙げることができ、これらの１種または２種以上を用いることができる。
【００２６】
また、一般式（２）で示されるポリアルキレングリコールエステル単量体としては、ヒドロキシエチル（メタ）アクリレート、ヒドロキシプロピル（メタ）アクリレート、ポリエチレングリコールモノ（メタ）アクリレート、ポリプロピレングリコールモノ（メタ）アクリレート、ポリブチレングリコールモノ（メタ）アクリレート、ポリエチレングリコールポリプロピレングリコールモノ（メタ）アクリレート、ポリエチレングリコールポリブチレングリコールモノ（メタ）アクリレート、ポリプロピレングリコールポリブチレングリコールモノ（メタ）アクリレート、ポリエチレングリコールポリプロピレングリコールポリブチレングリコールモノ（メタ）アクリレート、メトキシポリエチレングリコールモノ（メタ）アクリレート、メトキシポリプロピレングリコールモノ（メタ）アクリレート、メトキシポリブチレングリコールモノ（メタ）アクリレート、メトキシポリエチレングリコールポリプロピレングリコールモノ（メタ）アクリレート、メトキシポリエチレングリコールポリブチレングリコールモノ（メタ）アクリレート、メトキシポリプロピレングリコールポリブチレングリコールモノ（メタ）アクリレート、メトキシポリエチレングリコールポリプロピレングリコールポリブチレングリコールモノ（メタ）アクリレート、エトキシポリエチレングリコールモノ（メタ）アクリレート、エトキシポリプロピレングリコールモノ（メタ）アクリレート、エトキシポリブチレングリコールモノ（メタ）アクリレート、エトキシポリエチレングリコールポリプロピレングリコールモノ（メタ）アクリレート、エトキシポリエチレングリコールポリブチレングリコールモノ（メタ）アクリレート、エトキシポリプロピレングリコールポリブチレングリコールモノ（メタ）アクリレート、およびエトキシポリエチレングリコールポリプロピレングリコールポリブチレングリコールモノ（メタ）アクリレート等を挙げることができる。本発明では、不飽和ポリアルキレングリコール系単量体（ｂ）由来の構成単位（ＩＩ）として、これらの１種を単独で使用できるほか、２種以上を混合して使用してもよい。不飽和ポリアルキレングリコール系単量体（ｂ）のオキシアルキレン基の平均付加モル数ｍは１〜３００、好ましくは１〜１００の整数である。
【００２７】
また、一般式（２）で示される（メタ）アクリル酸エステルとしては、（メタ）アクリル酸メチル、（メタ）アクリル酸エチル、（メタ）アクリル酸ｎ−プロピル、（メタ）アクリル酸イソプロピル、（メタ）アクリル酸ｎ−ブチル、（メタ）アクリル酸イソブチル、（メタ）アクリル酸ｔｅｒｔブチル、（メタ）アクリル酸２−エチルヘキシル、（メタ）アクリル酸デシル、（メタ）アクリル酸シクロヘキシル等がある。
【００２８】
上記（メタ）アクリル酸系単量体の他に、該単量体と共重合し得る単量体を用いることができる。このような他の単量体としては、マレイン酸、フマル酸、シトラコン酸、メサコン酸、イタコン酸等のジカルボン酸類；これらのジカルボン酸類とＨＯ（Ｒ⁵Ｏ）_rＲ⁶（ただし、Ｒ⁵Ｏは炭素原子数２〜４のオキシアルキレン基の１種または２種以上の混合物を表わし、２種以上の場合はブロック状に付加していてもランダム状に付加していてもよく、ｒはオキシアルキレン基の平均付加モル数であり１から３００の整数を表わし、Ｒ⁶は水素または炭素原子数１〜２２、好ましくは１〜１５のアルキル基を表わす。）で表わされるアルコールとのモノエステルあるいはジエステル類；（メタ）アクリルアミド、（メタ）アクリルアルキルアミド等の不飽和アミド類；酢酸ビニル、プロピオン酸ビニル等のビニルエステル類；ビニルスルホン酸、（メタ）アリルスルホン酸、スルホエチル（メタ）アクリレート、２−メチルプロパンスルホン酸（メタ）アクリルアミド、スチレンスルホン酸等の不飽和スルホン酸類およびそれらの一価金属塩、二価金属塩、アルモニウム塩、有機アミン塩類；スチレン、α−メチルスチレン等の芳香族ビニル類；炭素原子数１〜１８、好ましくは１〜１５の脂肪族アルコールあるいはベンジルアルコール等のフェニル基含有アルコールと（メタ）アクリル酸とのエステル類；ポリアルキレングリコールモノ（メタ）アクリレート；ポリアルキレングリコールモノ（メタ）アリルエーテル等が挙げられ、これらの１種または２種以上を用いることができる。
【００２９】
本発明の（メタ）アクリル酸系重合体の製造方法において、重合方法は特に限定されるものではなく、溶液重合や塊状重合などの公知の方法を採用することができる。特に、反応の制御や、重合物の取り扱いやすさの点を考慮すると、溶液重合が好ましい。
【００３０】
溶媒中での重合は、回分式でも連続式でも行なうことができ、その際使用される溶媒としては、水；メチルアルコール、エチルアルコール、イソプロピルアルコール等の低級アルコール；ベンゼン、トルエン、キシレン、シクロヘキサン、ｎ−ヘキサン等の芳香族あるいは脂肪族炭化水素；酢酸エチル等のエステル化合物；アセトン、メチルエチルケトン等のケトン化合物；テトラヒドロフラン、ジオキサン等の環状エーテル化合物等が挙げられる。原料のエステル化物の単量体成分および得られる共重合体の溶解性ならびに該共重合体の使用時の便からは、水および炭素原子数１〜４の低級アルコールよりなる群から選ばれた少なくとも１種を用いることが好ましい。その場合、炭素原子数１〜４の低級アルコールの中でもメチルアルコール、エチルアルコール、イソプロピルアルコール等が特に有効である。この際、水の配合比は、好ましくは２０質量％以下、さらに好ましくは１０質量％以下、よりさらに好ましくは５質量％以下、最も好ましくは１質量％以下である。この割合が２０質量％を超えると、該重合体が分離及び／または沈殿する恐れがある。
【００３１】
上記アクリル酸系単量体ないしアクリル酸系単量体混合物は、重合開始剤の存在下に５０〜１４０℃、好ましくは８０〜１２０℃で重合反応に供される。
【００３２】
使用する重合開始剤としては特に限定されるものではないが、過酸化物などをあげることができ、例えば、過酸化水素；過硫酸ナトリウム、過硫酸アンモニウム、過硫酸カリウム等の過硫酸塩；２，２’−アゾビス（２−アミノジプロパン）２塩酸塩、４，４’−アゾビス（４−シアノバレリン酸）、アゾビスイソブチルニトリル、２，２’−アゾビス（４−メトキシ−２，４−ジメチルバレロニトリル）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、過コハク酸、ジ−ｔ−ブチルパーオサイド、ｔ−ブチルヒドロパーオサイド、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。これらの１種類のみであっても２種類以上含んでいてもよいが、過酸化水素、過硫酸塩、有機過酸化物、２，２’−アゾビス（２−アミノジプロパン）２塩酸塩が好ましく、過酸化水素、過硫酸塩、２，２’−アゾビス（２−アミノジプロパン）２塩酸塩がより好ましく、過硫酸塩、２，２’−アゾビス（２−アミノジプロパン）２塩酸塩がさらに好ましい。また、重合開始剤として過酸化物と還元剤や金属塩等を組み合わせてもよい。還元剤や金属塩等は、特に限定されるものではないが、亜硫酸水素ナトリウムやＦｅ²⁺、Ｆｅ³⁺、Ｃｕ⁺、Ｃｕ²⁺、Ｖ²⁺、Ｖ³⁺、ＶＯ²⁺等が挙げられ、亜硫酸水素ナトリウム、Ｆｅ²⁺、Ｆｅ³⁺、Ｃｕ⁺、Ｃｕ²⁺が好ましく、Ｆｅ²⁺、Ｆｅ³⁺、Ｃｕ⁺、Ｃｕ²⁺がより好ましい。Ｆｅ²⁺、Ｆｅ³⁺、Ｃｕ⁺、Ｃｕ²⁺を併用することにより、分散度（重量平均分子量／数平均分子量）が狭くなる。上記重合開始剤の添加量は、目的の分子量によって適宜設定すればよい。なお、滴下時の重合開始剤の濃度は、特に限定されないが、過硫酸塩が開始剤である場合には、好ましくは３〜５０質量％水溶液、より好ましくは５〜４０質量％水溶液、さらに好ましくは１０〜３０質量％水溶液である。アゾ系化合物の開始剤である場合には、好ましくは０．１〜５質量％水溶液、より好ましくは０．３〜３質量％水溶液、さらに好ましくは０．５〜２質量％水溶液である。なお、重合開始剤と還元剤や金属塩を組み合わせる時の還元剤や金属塩の添加量は特に限定は無いが、金属塩の場合には重合終了時の（メタ）アクリル酸系重合体に対して０．１ｐｐｍ〜１，０００ｐｐｍが好ましく、０．５ｐｐｍ〜５００ｐｐｍがより好ましく、１ｐｐｍ〜３００ｐｐｍがさらに好ましい。金属塩の添加量が０．１ｐｐｍ未満であると分散度を狭くする効果がなく、１，０００ｐｐｍを超えるともはや添加の効果が無く、経済的面から好ましくない。
【００３３】
【発明の効果】
以上述べたように、本発明による（メタ）アクリル酸系重合体の製造方法は、反応釜の頂部付近に設けられたフィードノズルより冷却下に（メタ）アクリル酸系単量体を主成分とする単量体を反応釜に供給し、加熱して重合反応を行なうものであるから、加熱されている反応釜へ熱重合を生じやすい該単量体を供給しても、フィードノズル部分が冷却されているので、該フィードノズル内で熱重合を生ずることなく、該フィードノズルを閉塞する恐れもない。
【００３４】
また、本発明による（メタ）アクリル酸系重合体の製造装置は、外部に加熱用ジャケットを備えた反応釜と、該反応釜の頂部より該反応釜内に突出して設けられた冷却器と、該冷却器内に貫通して設けられたフィードノズルとよりなるものであるから、供給される熱重合を起し易い（メタ）アクリル酸系重合体がフィードノズル内で熱重合して該ノズルを閉塞する恐れはなくなる。
【図面の簡単な説明】
【図１】 本発明による（メタ）アクリル酸系重合体の製造装置の概略断面図。
【図２】 図１に示す製造装置におけるフィードノズル部の拡大断面図。
【符号の説明】
１…加熱ジャケット、
２…反応釜、
３…反応釜頂部、
４…冷却器、
５…フィードノズル、
６…冷却器の冷却媒体受器、
７…冷却媒体供給管、
８…冷却媒体排出口。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and an apparatus for producing a (meth) acrylic acid polymer. More specifically, the present invention relates to a method and an apparatus for producing a (meth) acrylic acid polymer capable of preventing thermal polymerization at a feed nozzle portion.
[0002]
[Prior art]
Conventionally, poly (meth) acrylic acid homopolymers and (meth) polymerized (meth) acrylic monomers such as (meth) acrylic acid, (meth) acrylates, (meth) acrylic acid esters, etc. When the acrylic acid copolymer is produced, a monomer feed nozzle in the reaction kettle is installed, but when the polymerization reaction is started, the feed nozzle portion increases as the temperature in the kettle increases. Is also heated. As a result, if a substance that easily causes (polymerization) reaction due to heat, such as a monomer, is supplied from the feed nozzle, the temperature of the feed nozzle also rises, so that the (polymerization) reaction occurs in the feed nozzle portion. There is. Therefore, there is a problem that the feed nozzle is blocked by the polymer.
[0003]
[Problems to be solved by the invention]
Accordingly, an object of the present invention is to provide a method and an apparatus for producing a (meth) acrylic acid polymer capable of preventing thermal polymerization at a feed nozzle portion of a reaction kettle.
[0004]
[Means for solving the problems]
The said subject is achieved by the following (1)-(4).
[0005]
(1) (A) a reaction kettle provided with a heating jacket outside,
(B) a cooling medium receiver provided in a substantially vertical direction, a cooling medium supply pipe inserted downward from the upper part of the cooling medium receiver and having an open lower end, and an upper part of the cooling medium receiver A cooling medium outlet formed in the reactor, and a cooler provided to protrude from the top of the reaction kettle into the reaction kettle,
(C) a feed nozzle provided with a lower tip inclined inward from the top in the cooler and provided penetrating into the cooler;
An apparatus for producing a (meth) acrylic acid polymer.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Next, the manufacturing apparatus used in the present invention will be described.
[0010]
That is, as shown in FIG. 1, the production apparatus of the present invention includes a reaction kettle 2 provided with a heating jacket 1 on the outside, and a cooler provided to protrude into the reaction kettle 2 from the top 3 of the reaction kettle. As shown in FIGS. 1 and 2, a feed nozzle 5 for supplying a monomer is provided in the cooler 4 so as to penetrate the cooler 4 from the upper part to the lower part. ing.
[0011]
The cooler 4 may be of any form as long as it cools the feed nozzle 5, but as an example, as shown in FIG. A cooling medium receiver 6 provided in a vertical direction, a cooling medium supply pipe 7 inserted downward from the upper part of the cooling medium receiver 6 and having an open lower end, and an upper part of the cooling medium receiver The cooling medium outlet 8 is provided. The cooler is not limited to the structure as described above, and various types can be used. Examples of such a cooler include a jacket type provided around the feed nozzle, a shell-and-tube type, and the like.
[0012]
A feed nozzle 5 is provided in the cooler 4 from the top to the bottom, and the tip of the feed nozzle 5 passes through the bottom 8 of the cooling medium receiver 6 of the cooler 4 to react. Opened inside the hook 2. However, it is not necessarily such a structure, and of course, a structure penetrating the side wall of the cooling medium receiver 6 may be used.
[0013]
On the other hand, the upper end portion of the feed nozzle 5 is provided so as to penetrate the ceiling portion of the cooling medium receiver 6 as shown in FIG. However, in addition to this, an upper portion of the side wall may be provided.
[0014]
The tip opening of the feed nozzle 5 is preferably as far away from the side wall of the reaction vessel 2 as possible. That is, since the side wall of the reaction vessel 2 is heated by the jacket 1, when the supplied monomer comes into contact with the side wall of the reaction vessel 2, a polymerization reaction occurs immediately, and it is difficult to obtain a uniform polymer. Because it becomes. Therefore, for example, as shown in FIG. 2, the lower tip of the feed nozzle 5 is inclined toward the inside of the reaction vessel 2 and is preferably used. In addition, the feed nozzle 5 has a configuration in which the feed nozzle 5 descends in a spiral shape downward from the top, and the opening tip is directed to the inner space side of the reaction vessel as much as possible, and the tip direction is directed to the inner space side. .
[0015]
In the reaction kettle, if necessary, a stirring device comprising a stirring shaft 10 provided with a stirring blade 9 is provided.
[0016]
In carrying out the method of the present invention, in the manufacturing apparatus shown in FIGS. 1 and 2, first, a cooling medium, for example, water is supplied from the supply port 11 of the cooling medium supply pipe, and the cooling medium is supplied from the lower end portion 12 thereof. By discharging, the inside of the cooling medium receiver 6 is raised and discharged from the cooling medium discharge port 8, for example, by overflowing.
[0017]
Next, the raw material monomer (monomer or monomer mixture and polymerization initiator) is supplied from the supply port 13 of the feed nozzle 5 while keeping the temperature in the cooler at a predetermined temperature in this way. Then, the feed nozzle 5 is discharged into the reaction kettle 2 from the tip opening 8. The cooling temperature of the monomer at this time is 0.5 to 90 ° C., preferably 1 to 30 ° C., more preferably 1 to 10 ° C., and the temperature of the cooler is 0.2 to 60 ° C., preferably 0. It is 5-20 degreeC, More preferably, it is 0.5-8 degreeC. The raw material supplied to the reaction kettle is heated and, if necessary, provided with stirring.
[0018]
As a heating method, any method such as internal heating or external heating can be used. For example, a heating medium such as steam is supplied into the heating jacket 1 from the heating medium supply port 14. There is a method of discharging from the heating medium discharge port 15.
[0019]
According to the method of the present invention, as a raw material monomer, as a (meth) acrylic acid monomer, an acrylic acid monomer such as (meth) acrylic acid, (meth) acrylic acid salt, (meth) acrylic acid ester, etc. Is a monomer or a monomer mixture containing the (meth) acrylic acid monomer as a main component, and the main component means that it contains 50 mol% or more of the (meth) acrylic monomer. .
[0020]
Examples of (meth) acrylic acid and salts thereof include, for example, the general formula (1)
[0021]
[Chemical 1]

[0022]
In the formula, R ¹ represents hydrogen or a methyl group, and M represents hydrogen, a monovalent metal, a divalent metal, an ammonium group, or an organic amine group.
[0023]
Moreover, as (meth) acrylic acid ester, general formula (2)
[0024]
[Chemical 2]

[0025]
(However, in the formula, R ¹ represents hydrogen or a methyl group, R ² represents —COO (R ³ O) _m R ⁴ or —COOR ⁵ , and R ³ O represents an oxyalkylene group having 2 to 4 carbon atoms. Represents a seed or a mixture of two or more kinds, and in the case of two or more kinds, it may be added in a block form or randomly, and R ⁴ is hydrogen or C 1-22, preferably 1-10. M represents the average number of added moles of the oxyalkylene group and represents an integer of 1 to 300, and R ⁵ represents an alkyl group having 1 to 22 carbon atoms, preferably 1 to 10 carbon atoms.)
Examples of the monomer represented by the general formula (1) used in the present invention include acrylic acid, methacrylic acid, and monovalent metal salts, divalent metal salts, ammonium salts, and organic amine salts of these acids. 1 type, or 2 or more types of these can be used.
[0026]
Examples of the polyalkylene glycol ester monomer represented by the general formula (2) include hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, Polybutylene glycol mono (meth) acrylate, polyethylene glycol polypropylene glycol mono (meth) acrylate, polyethylene glycol polybutylene glycol mono (meth) acrylate, polypropylene glycol polybutylene glycol mono (meth) acrylate, polyethylene glycol polypropylene glycol polybutylene glycol mono ( (Meth) acrylate, methoxypolyethylene glycol mono (meth) acrylate, Xypolypropylene glycol mono (meth) acrylate, methoxypolybutylene glycol mono (meth) acrylate, methoxypolyethylene glycol polypropylene glycol mono (meth) acrylate, methoxypolyethylene glycol polybutylene glycol mono (meth) acrylate, methoxypolypropylene glycol polybutylene glycol mono ( (Meth) acrylate, methoxypolyethylene glycol polypropylene glycol polybutylene glycol mono (meth) acrylate, ethoxypolyethylene glycol mono (meth) acrylate, ethoxypolypropylene glycol mono (meth) acrylate, ethoxypolybutylene glycol mono (meth) acrylate, ethoxypolyethyleneglycol polypropylene Recall mono (meth) acrylate, ethoxy polyethylene glycol polybutylene glycol mono (meth) acrylate, ethoxy polypropylene glycol polybutylene glycol mono (meth) acrylate, ethoxy polyethylene glycol polypropylene glycol polybutylene glycol mono (meth) acrylate, etc. it can. In the present invention, as the structural unit (II) derived from the unsaturated polyalkylene glycol monomer (b), one of these may be used alone, or two or more may be mixed and used. The average added mole number m of the oxyalkylene group of the unsaturated polyalkylene glycol monomer (b) is an integer of 1 to 300, preferably 1 to 100.
[0027]
The (meth) acrylic acid ester represented by the general formula (2) includes methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, ( Examples include n-butyl (meth) acrylate, isobutyl (meth) acrylate, tertbutyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, decyl (meth) acrylate, and cyclohexyl (meth) acrylate.
[0028]
In addition to the (meth) acrylic acid monomer, a monomer that can be copolymerized with the monomer can be used. Examples of such other monomers include dicarboxylic acids such as maleic acid, fumaric acid, citraconic acid, mesaconic acid, and itaconic acid; these dicarboxylic acids and HO (R ⁵ O) _r R ⁶ (however, R ⁵ O Represents one kind or a mixture of two or more kinds of oxyalkylene groups having 2 to 4 carbon atoms, and in the case of two or more kinds, they may be added in blocks or randomly, and r is oxy An average added mole number of an alkylene group, which represents an integer of 1 to 300, and R ⁶ represents hydrogen or an alkyl group having 1 to 22 carbon atoms, preferably 1 to 15 carbon atoms). Diesters; unsaturated amides such as (meth) acrylamide and (meth) acrylalkylamide; vinyl esters such as vinyl acetate and vinyl propionate; vinyl sulfo Acids, (meth) allylsulfonic acid, sulfoethyl (meth) acrylate, 2-methylpropanesulfonic acid (meth) acrylamide, unsaturated sulfonic acids such as styrenesulfonic acid, and their monovalent metal salts, divalent metal salts, and aluminum salts Organic amine salts; aromatic vinyls such as styrene and α-methylstyrene; phenyl group-containing alcohols such as aliphatic alcohols or benzyl alcohols having 1 to 18, preferably 1 to 15 carbon atoms, and (meth) acrylic acid; Esters, polyalkylene glycol mono (meth) acrylates, polyalkylene glycol mono (meth) allyl ethers, and the like, and one or more of these may be used.
[0029]
In the method for producing a (meth) acrylic acid polymer of the present invention, the polymerization method is not particularly limited, and a known method such as solution polymerization or bulk polymerization can be employed. In particular, solution polymerization is preferable in consideration of reaction control and ease of handling of the polymer.
[0030]
Polymerization in a solvent can be carried out either batchwise or continuously. The solvent used here is water; lower alcohols such as methyl alcohol, ethyl alcohol, isopropyl alcohol; benzene, toluene, xylene, cyclohexane, Examples include aromatic or aliphatic hydrocarbons such as n-hexane; ester compounds such as ethyl acetate; ketone compounds such as acetone and methyl ethyl ketone; and cyclic ether compounds such as tetrahydrofuran and dioxane. From the solubility of the monomer component of the raw material esterified product and the obtained copolymer and the convenience during use of the copolymer, at least selected from the group consisting of water and a lower alcohol having 1 to 4 carbon atoms One type is preferably used. In that case, among the lower alcohols having 1 to 4 carbon atoms, methyl alcohol, ethyl alcohol, isopropyl alcohol and the like are particularly effective. At this time, the mixing ratio of water is preferably 20% by mass or less, more preferably 10% by mass or less, still more preferably 5% by mass or less, and most preferably 1% by mass or less. When this ratio exceeds 20% by mass, the polymer may be separated and / or precipitated.
[0031]
The acrylic acid monomer or acrylic acid monomer mixture is subjected to a polymerization reaction at 50 to 140 ° C., preferably 80 to 120 ° C. in the presence of a polymerization initiator.
[0032]
Although it does not specifically limit as a polymerization initiator to be used, A peroxide etc. can be mention | raise | lifted, for example, hydrogen peroxide; persulfates, such as sodium persulfate, ammonium persulfate, potassium persulfate; 2′-azobis (2-aminodipropane) dihydrochloride, 4,4′-azobis (4-cyanovaleric acid), azobisisobutylnitrile, 2,2′-azobis (4-methoxy-2,4-dimethylvalero) Azo compounds such as nitrile); organic peroxides such as benzoyl peroxide, lauroyl peroxide, peracetic acid, persuccinic acid, di-t-butyl peroxide, t-butyl hydroperoxide, cumene hydroperoxide Etc. These may be one kind or two or more kinds, but hydrogen peroxide, persulfate, organic peroxide, and 2,2′-azobis (2-aminodipropane) dihydrochloride are preferable. Hydrogen peroxide, persulfate, and 2,2′-azobis (2-aminodipropane) dihydrochloride are more preferable, and persulfate and 2,2′-azobis (2-aminodipropane) dihydrochloride are preferable. Further preferred. Moreover, you may combine a peroxide, a reducing agent, a metal salt, etc. as a polymerization initiator. The reducing agent and the metal salt are not particularly limited, and examples thereof include sodium bisulfite, Fe ²⁺ , Fe ³⁺ , Cu ⁺ , Cu ²⁺ , V ²⁺ , V ³⁺ , VO ^{2+ and the} like. Sodium bisulfite, Fe ²⁺ , Fe ³⁺ , Cu ⁺ and Cu ²⁺ are preferable, and Fe ²⁺ , Fe ³⁺ , Cu ⁺ and Cu ²⁺ are more preferable. By using Fe ²⁺ , Fe ³⁺ , Cu ⁺ , and Cu ²⁺ together, the degree of dispersion (weight average molecular weight / number average molecular weight) is narrowed. What is necessary is just to set the addition amount of the said polymerization initiator suitably with the target molecular weight. The concentration of the polymerization initiator at the time of dropping is not particularly limited, but when persulfate is the initiator, it is preferably 3 to 50% by mass aqueous solution, more preferably 5 to 40% by mass aqueous solution, and further preferably Is a 10-30 mass% aqueous solution. When it is an initiator of an azo compound, it is preferably a 0.1 to 5% by mass aqueous solution, more preferably a 0.3 to 3% by mass aqueous solution, and still more preferably a 0.5 to 2% by mass aqueous solution. The amount of the reducing agent or metal salt added when the polymerization initiator is combined with the reducing agent or metal salt is not particularly limited. In the case of a metal salt, the amount of the (meth) acrylic acid polymer at the end of the polymerization is not limited. 0.1 ppm to 1,000 ppm is preferred, 0.5 ppm to 500 ppm is more preferred, and 1 ppm to 300 ppm is even more preferred. If the addition amount of the metal salt is less than 0.1 ppm, there is no effect of narrowing the degree of dispersion, and if it exceeds 1,000 ppm, the addition effect is no longer effective, which is not preferable from an economical viewpoint.
[0033]
【The invention's effect】
As described above, the method for producing a (meth) acrylic acid polymer according to the present invention comprises a (meth) acrylic acid monomer as a main component under cooling from a feed nozzle provided near the top of the reaction kettle. Since the monomer to be fed is supplied to the reaction kettle and heated to conduct the polymerization reaction, the feed nozzle portion is cooled even if the monomer that is likely to cause thermal polymerization is fed to the heated kettle. Therefore, there is no possibility of clogging the feed nozzle without causing thermal polymerization in the feed nozzle.
[0034]
Further, the (meth) acrylic acid polymer production apparatus according to the present invention includes a reaction kettle provided with a heating jacket on the outside, a cooler provided to protrude from the top of the reaction kettle into the reaction kettle, Since the feed nozzle is provided penetrating in the cooler, the (meth) acrylic acid polymer that easily causes thermal polymerization is thermally polymerized in the feed nozzle to There is no risk of blockage.
[Brief description of the drawings]
FIG. 1 is a schematic sectional view of an apparatus for producing a (meth) acrylic acid polymer according to the present invention.
FIG. 2 is an enlarged sectional view of a feed nozzle portion in the manufacturing apparatus shown in FIG.
[Explanation of symbols]
1 ... heating jacket,
2 ... reaction kettle,
3 ... Reaction kettle top,
4 ... Cooler,
5 ... feed nozzle,
6 ... Cooling medium receiver of the cooler,
7 ... cooling medium supply pipe,
8 ... Cooling medium outlet.

Claims (1)

(A) a reaction kettle equipped with an external heating jacket;
(B) a cooling medium receiver provided in a substantially vertical direction, a cooling medium supply pipe inserted downward from the upper part of the cooling medium receiver and having an open lower end, and an upper part of the cooling medium receiver A cooling medium outlet formed in the reactor, and a cooler provided to protrude from the top of the reaction kettle into the reaction kettle,
(C) a feed nozzle provided with a lower tip inclined inward from the top in the cooler and provided penetrating into the cooler;
An apparatus for producing a (meth) acrylic acid polymer.

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