JPH11279207A - Production of highly water-soluble resin - Google Patents
Production of highly water-soluble resinInfo
- Publication number
- JPH11279207A JPH11279207A JP10078705A JP7870598A JPH11279207A JP H11279207 A JPH11279207 A JP H11279207A JP 10078705 A JP10078705 A JP 10078705A JP 7870598 A JP7870598 A JP 7870598A JP H11279207 A JPH11279207 A JP H11279207A
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- monomer
- water
- weight
- dispersion medium
- dispersant
- Prior art date
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Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、衛生品等に使用さ
れる高吸水性樹脂の製法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a superabsorbent resin used for sanitary goods and the like.
【０００２】[0002]
【従来の技術及び発明が解決しようとする課題】高吸水
性樹脂は、衛生用品分野で、幼児用、大人用もしくは失
禁者用の紙おむつ（使い捨ておむつ）又は婦人用の生理
用ナプキン等の吸収性物品における吸水性物質として使
用されている。現在、高吸水性樹脂としては、ポリアク
リル酸系高吸水性樹脂がその主流を占めている。2. Description of the Related Art Superabsorbent resins are used in the field of hygiene products such as disposable diapers (disposable diapers) for infants, adults or incontinent persons or sanitary napkins for women. It is used as a water-absorbing substance in articles. At present, polyacrylic acid-based superabsorbent resins dominate as superabsorbent resins.
【０００３】水溶性ビニルモノマー、とりわけアクリル
酸モノマーの重合により行われる高吸水性樹脂の製法に
おいて、重合開始剤として一般に、過硫酸塩、過酸化
物、アゾ化合物、過酸化物と還元剤を組み合わせるレド
ックス系開始剤等が用いられるが、実際に工業的生産を
考えた場合、過酸化物は爆発の危険性を有するなど取り
扱いに注意を要するものが多く好ましくない。過硫酸塩
は安価で安全性も高く、もっとも一般的に使用されてい
るが、重合開始能とともに自己架橋も併発することが知
られている。高吸水能を有する吸水性樹脂を得る場合、
架橋度を下げることが要求されるが、過硫酸塩を使用す
ると自己架橋が起こるために十分な吸水能を有する樹脂
が得られない。自己架橋を抑えるために過硫酸塩の使用
量を減らすことが特開平６−２８７２３３号公報に開示
されているが、過硫酸塩の減量は実質的に開始剤を減ら
すことになるため、重合率の低下とそれによる未反応モ
ノマー量の増加、重合の不安定化を招きやすい。アゾ化
合物を開始剤として用いれば自己架橋は抑えられるが、
重合率が低く未反応モノマー量が多い上、現状では単価
が経済上不利となる。[0003] In the production of a superabsorbent resin produced by the polymerization of a water-soluble vinyl monomer, especially an acrylic acid monomer, a persulfate, a peroxide, an azo compound, a peroxide and a reducing agent are generally used as a polymerization initiator. A redox initiator is used, but when industrial production is actually considered, peroxides are not preferred because many peroxides have a risk of explosion and require careful handling. Persulfates are inexpensive and highly safe, and are most commonly used. However, it is known that self-crosslinking occurs simultaneously with the ability to initiate polymerization. When obtaining a water-absorbing resin having high water absorption capacity,
Although it is required to reduce the degree of cross-linking, the use of persulfate causes self-cross-linking, so that a resin having sufficient water-absorbing ability cannot be obtained. Japanese Unexamined Patent Publication No. Hei 6-287233 discloses that the amount of persulfate used is reduced to suppress self-crosslinking. However, since the reduction of persulfate substantially reduces the amount of the initiator, the polymerization rate is reduced. , The amount of unreacted monomer increases, and the polymerization becomes unstable. If an azo compound is used as an initiator, self-crosslinking can be suppressed,
The polymerization rate is low, the amount of unreacted monomer is large, and the unit price is economically disadvantageous at present.
【０００４】また、架橋度の低い樹脂は含水したゲルの
状態での強度、すなわち加圧状態での保型性や吸水能、
経時安定性等が不十分となり易い。この含水ゲルの耐久
性等の向上を目的として、最近、特定のチタン化合物を
含有させる方法（特開平６−３０６１１８号公報及び同
７−６２２５２号公報）等があるが、高吸水性樹脂に添
加剤を加える方法は、実生産において、添加設備の増
設、工程の複雑化を招き、経済上不利となる。A resin having a low degree of crosslinking has a strength in a state of a gel containing water, that is, a shape retaining property and a water absorbing ability under a pressurized state.
The aging stability and the like are likely to be insufficient. For the purpose of improving the durability and the like of the hydrogel, there has recently been a method of containing a specific titanium compound (JP-A-6-306118 and JP-A-7-62252). The method of adding the agent causes an increase in addition equipment and a complicated process in actual production, which is economically disadvantageous.
【０００５】従って、本発明の目的は、高吸水倍率を有
し、しかも、含水状態での経時安定性が良好な吸水性樹
脂を、添加剤等を加えることなく簡便に且つ安価に、再
現良く製造する方法を提供することにある。Accordingly, it is an object of the present invention to provide a water-absorbent resin having a high water absorption capacity and good stability over time in a water-containing state, simply, inexpensively and without reproducibility without adding additives. It is to provide a manufacturing method.
【０００６】[0006]
【課題を解決するための手段】本発明は、水溶性ビニル
モノマー（以下、モノマーという）水溶液を、疎水性有
機溶媒を含有する分散媒中へ供給し、逆相懸濁重合して
高吸水性樹脂を得るに際し、モノマー全体量の５０重量
％が上記分散媒中へ供給される迄の該分散媒中への供給
モノマー水溶液のモノマー最低濃度（ａ1 重量％）と、
これ以降の該分散媒中への供給モノマー水溶液のモノマ
ー最低濃度（ａ2 重量％）とを比較したとき、ａ1 ＜ａ
2 であることを特徴とする高吸水性樹脂の製法を提供す
ることにより、上記目的を達成したものである。According to the present invention, an aqueous solution of a water-soluble vinyl monomer (hereinafter referred to as "monomer") is supplied into a dispersion medium containing a hydrophobic organic solvent, and is subjected to reverse phase suspension polymerization to obtain a highly water-absorbent polymer. In obtaining the resin, the lowest monomer concentration (a 1 % by weight) of the aqueous monomer solution supplied to the dispersion medium until 50% by weight of the total amount of the monomers is supplied to the dispersion medium,
From the comparison with the lowest monomer concentration (a 2 % by weight) of the aqueous monomer solution supplied into the dispersion medium, a 1 <a
The above object has been attained by providing a method for producing a highly water-absorbent resin, which is characterized by being 2 .
【０００７】[0007]
【発明の実施の形態】以下、本発明の高吸水性樹脂の製
法について詳細に説明する。本発明に用いられるモノマ
ーとしては、水溶性で、重合性の不飽和基を有する種々
のビニルモノマーが挙げられ、具体的には、オレフィン
系不飽和カルボン酸又はその塩、オレフィン系不飽和カ
ルボン酸エステル、オレフィン系不飽和スルホン酸又は
その塩、オレフィン系不飽和リン酸又はその塩、オレフ
ィン系不飽和リン酸エステル、オレフィン系不飽和アミ
ン、オレフィン系不飽和アンモニウム、及びオレフィン
系不飽和アミドなどの重合性不飽和基を有するビニルモ
ノマーが例示される。これらの中でも、特にオレフィン
系不飽和カルボン酸及びその塩が好ましく用いられ、更
に好ましくは、アクリル酸、メタクリル酸、及びこれら
のアルカリ金属塩、アンモニウム塩が用いられ、一層好
ましくは、アクリル酸、アクリル酸アルカリ金属塩（ナ
トリウム塩、カリウム塩等）、及びアクリル酸アンモニ
ウム塩が用いられる。これらのモノマーは１種以上で使
用することができる。BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a method for producing a superabsorbent resin of the present invention will be described in detail. Examples of the monomer used in the present invention include various vinyl monomers having a water-soluble, polymerizable unsaturated group, and specifically, olefinically unsaturated carboxylic acids or salts thereof, and olefinically unsaturated carboxylic acids. Esters, olefinically unsaturated sulfonic acids or salts thereof, olefinically unsaturated phosphoric acids or salts thereof, olefinically unsaturated phosphates, olefinically unsaturated amines, olefinically unsaturated ammonium, and olefinically unsaturated amides. A vinyl monomer having a polymerizable unsaturated group is exemplified. Among these, olefinic unsaturated carboxylic acids and salts thereof are particularly preferably used, more preferably acrylic acid, methacrylic acid, and alkali metal salts and ammonium salts thereof, and more preferably acrylic acid and acrylic acid. Acid alkali metal salts (sodium salt, potassium salt, etc.) and ammonium acrylate are used. One or more of these monomers can be used.
【０００８】また、モノマーは、これと共重合し得る水
不溶性ビニルモノマーと併用することもできる。該水不
溶性ビニルモノマーとしては、例えば、炭素数１〜１８
のアルキル基を有するアクリル酸、メタクリル酸、マレ
イン酸、フマール酸などの不飽和カルボン酸エステルモ
ノマーなどが挙げられる。この場合、モノマーは、全ビ
ニルモノマー中に５０重量％以上、特に７０重量％以上
含有していることが好ましい。The monomer can be used in combination with a water-insoluble vinyl monomer copolymerizable therewith. Examples of the water-insoluble vinyl monomer include, for example, those having 1 to 18 carbon atoms.
And unsaturated carboxylic acid ester monomers such as acrylic acid, methacrylic acid, maleic acid, and fumaric acid having an alkyl group. In this case, the monomer is preferably contained in an amount of 50% by weight or more, particularly 70% by weight or more in all vinyl monomers.
【０００９】本発明に用いられる分散媒は、重合に不活
性な疎水性有機溶媒を含有する。疎水性有機溶媒として
は、例えば、ｎ−ペンタン、シクロペンタン、ｎ−ヘキ
サン、シクロヘキサン、ｎ−ヘプタン、メチルシクロヘ
キサンなどの脂肪族炭化水素、ベンゼン、トルエンなど
の芳香族炭化水素、ｎ−ブチルアルコール、ｎ−アミル
アルコールなどの炭素数４〜６の脂肪族アルコール、メ
チルエチルケトンなどの脂肪族ケトン、酢酸エチルなど
の脂肪族エステル類などを挙げることができる。これら
の疎水性有機溶媒は１種以上で使用することができる。[0009] The dispersion medium used in the present invention contains a hydrophobic organic solvent inert to polymerization. As the hydrophobic organic solvent, for example, n-pentane, cyclopentane, n-hexane, cyclohexane, n-heptane, aliphatic hydrocarbons such as methylcyclohexane, benzene, aromatic hydrocarbons such as toluene, n-butyl alcohol, Examples thereof include aliphatic alcohols having 4 to 6 carbon atoms such as n-amyl alcohol, aliphatic ketones such as methyl ethyl ketone, and aliphatic esters such as ethyl acetate. One or more of these hydrophobic organic solvents can be used.
【００１０】疎水性有機溶媒の使用量は、モノマー又は
モノマー水溶液１００重量部に対して、通常、好ましく
は５０〜５００重量部、更に好ましくは１００〜５００
重量部である。The amount of the hydrophobic organic solvent used is usually preferably 50 to 500 parts by weight, more preferably 100 to 500 parts by weight, per 100 parts by weight of the monomer or the aqueous monomer solution.
Parts by weight.
【００１１】また、上記分散媒には、上記疎水性有機溶
媒以外に、両親媒性の溶剤を加えてもよい。該両親媒性
の溶剤としては、メタノール、エタノール、プロパノー
ル、及び２−プロパノールなどのアルコール類、アセト
ンなどのケトン類、及びテトラヒドロフラン及びジオキ
サンなどのエーテル類が挙げられる。該両親媒性の溶剤
の使用量は、該疎水性有機溶媒との合計量で、モノマー
１００重量部に対し５００重量部までの量であることが
好ましい。Further, an amphiphilic solvent may be added to the dispersion medium in addition to the hydrophobic organic solvent. Examples of the amphiphilic solvent include alcohols such as methanol, ethanol, propanol, and 2-propanol; ketones such as acetone; and ethers such as tetrahydrofuran and dioxane. The amount of the amphiphilic solvent used is preferably up to 500 parts by weight based on 100 parts by weight of the monomer in total with the hydrophobic organic solvent.
【００１２】本発明において、モノマー全体量の５０重
量％、好ましくは２５重量％、更に好ましくは１０重量
％が上記分散媒中へ供給される迄の該分散媒中への供給
モノマー水溶液のモノマー最低濃度（ａ1 重量％）と、
これ以降の該分散媒中への供給モノマー水溶液のモノマ
ー最低濃度（ａ2 重量％）とを比較したとき、ａ1 ＜ａ
2 である。ａ1 は好ましくは１〜５０、更に好ましくは
１０〜５０であり、ａ 2 は好ましくは１０〜６０、更に
好ましくは２０〜６０である。上記分散媒中への供給モ
ノマー水溶液のモノマー濃度は、分散媒中に添加される
水及び水溶性成分の全ての中におけるモノマーの占める
割合を示すものである。従って、モノマー濃度を上記の
濃度に調整するには、あらかじめモノマー水溶液中に水
を加えることによる方法の他に、モノマーを分散媒中に
添加する際に、同時に並行して水を分散媒中に添加する
方法や、あらかじめ所定量の水を分散媒中に共存させて
おき、ここへモノマー水溶液を添加する方法によっても
良い。ａ1 ＜ａ2 の条件が満足されない場合には、得ら
れた高吸水性樹脂の含水状態での経時安定性が低下する
ため、本発明の目的を達成できない。In the present invention, 50 times the total amount of the monomers is used.
%, Preferably 25% by weight, more preferably 10% by weight
% Into the dispersion medium until the% is supplied into the dispersion medium
Minimum monomer concentration of aqueous monomer solution (a1Wt%) and
Subsequent monomers of the aqueous monomer solution supplied to the dispersion medium
-Minimum concentration (aTwo% By weight)1<A
TwoIt is. a1Is preferably 1 to 50, more preferably
10 to 50, a TwoIs preferably 10 to 60, more preferably
Preferably it is 20-60. Supply mode into the dispersion medium
Monomer aqueous monomer concentration is added to the dispersion medium
Monomers account for all of the water and water-soluble components
It shows the ratio. Therefore, the monomer concentration is
To adjust the concentration, first add water to the aqueous monomer solution.
In addition to the method by adding
At the same time as the addition, add water to the dispersion medium in parallel
Method and by pre-determining a certain amount of water in the dispersion medium
And the method of adding the monomer aqueous solution here
good. a1<ATwoIf the condition is not satisfied,
Stability of the superabsorbent resin deteriorated over time
Therefore, the object of the present invention cannot be achieved.
【００１３】上記分散媒中への供給モノマー水溶液のモ
ノマー濃度は、モノマー供給開始時に、最低濃度とする
ことがさらに好ましい。It is more preferable that the monomer concentration of the aqueous monomer solution supplied into the dispersion medium be the minimum concentration at the start of monomer supply.
【００１４】本発明における逆相懸濁重合に際してのモ
ノマーの重合温度は、好ましくは２０〜１２０℃、更に
好ましくは４０〜１００℃である。In the present invention, the polymerization temperature of the monomer in the reverse phase suspension polymerization is preferably 20 to 120 ° C, more preferably 40 to 100 ° C.
【００１５】本発明における逆相懸濁重合に際しては、
分散剤を用いることができる。分散剤としては、例え
ば、ソルビタンモノステアレート、ソルビタンモノラウ
レート及びポリオキシメチレンソルビタンモノオレート
等のソルビタン脂肪酸エステル、トリメチルステアリル
アンモニウムクロリド及びカルボキシメチルジメチルセ
チルアンモニウム等の陽オン性及び両性の界面活性剤、
ポリオキシエチレンドデシルエーテル硫酸エステルナト
リウム塩及びドデシルエーテル硫酸エステルナトリウム
塩等の陰イオン性界面活性剤、アルキルグルコシド等の
グリコシド化合物、エチルセルロース及びベンジルセル
ロース等のセルロースエーテル、セルロースアセテー
ト、セルロースブチレート及びセルロースアセテートブ
チレート等のセルロースエステル、マレイン化ポリブタ
ジエン、マレイン化ポリエチレン、マレイン化α−オレ
フィン、スチレン−ジメチルアミノエチルメタクリレー
ト４級塩及びイソプロピルメタクリレート−ジメチルア
ミノエチルメタクリレート４級塩等の高分子分散剤を挙
げることができる。上記分散剤としては、上述した化合
物の中でもイオン性界面活性剤を用いるのが好ましく、
更には、陰イオン性界面活性剤を用いるのが好ましい。
これらの分散剤は１種以上で使用することができる。[0015] In the reverse phase suspension polymerization in the present invention,
Dispersants can be used. As the dispersant, for example, sorbitan monostearate, sorbitan fatty acid esters such as sorbitan monolaurate and polyoxymethylene sorbitan monooleate, cationic and amphoteric surfactants such as trimethylstearyl ammonium chloride and carboxymethyldimethylcetyl ammonium ,
Anionic surfactants such as polyoxyethylene dodecyl ether sulfate sodium salt and sodium dodecyl ether sulfate, glycoside compounds such as alkyl glucoside, cellulose ethers such as ethyl cellulose and benzyl cellulose, cellulose acetate, cellulose butyrate and cellulose acetate Polymer dispersants such as cellulose esters such as butyrate, maleated polybutadiene, maleated polyethylene, maleated α-olefin, styrene-dimethylaminoethyl methacrylate quaternary salt, and isopropyl methacrylate-dimethylaminoethyl methacrylate quaternary salt. Can be. As the dispersant, it is preferable to use an ionic surfactant among the compounds described above,
Further, it is preferable to use an anionic surfactant.
One or more of these dispersants can be used.
【００１６】また、本発明における逆相懸濁重合に際し
ては、公知の重合開始剤が用いられる。例えば、ジアル
キルパーオキシド、ハイドロパーオキシド類、過硫酸
塩、ハロゲン酸塩、アゾ化合物、過酸化水素／第１鉄
塩、過硫酸塩／亜硫酸塩、クメンヒドロパーオキシド／
第１鉄塩、過酸化水素／Ｌ−アスコルビン酸等のレドッ
クス系開始剤を挙げることができる。これらの重合開始
剤は１種以上で使用することができる。これらの重合開
始剤の中でも、過硫酸塩、２，２’−アゾビス（２−ア
ミジノプロパン）ジヒドロクロリドが好ましく用いられ
る。In the reverse phase suspension polymerization in the present invention, a known polymerization initiator is used. For example, dialkyl peroxides, hydroperoxides, persulfates, halogenates, azo compounds, hydrogen peroxide / ferrous salts, persulfates / sulfites, cumene hydroperoxide /
Redox initiators such as ferrous salts and hydrogen peroxide / L-ascorbic acid can be mentioned. One or more of these polymerization initiators can be used. Among these polymerization initiators, persulfate and 2,2′-azobis (2-amidinopropane) dihydrochloride are preferably used.
【００１７】上記重合開始剤の添加量は、重合を円滑に
行うために、モノマー１００重量部に対して、好ましく
は０．０１〜１０重量部、更に好ましくは０．０２〜５
重量部である。また、上記重合開始剤の添加方法は、特
に制限されないが、上記重合開始剤をモノマー水溶液に
予め添加する方法が好ましい。The amount of the polymerization initiator to be added is preferably 0.01 to 10 parts by weight, more preferably 0.02 to 5 parts by weight, based on 100 parts by weight of the monomer in order to smoothly carry out the polymerization.
Parts by weight. The method of adding the polymerization initiator is not particularly limited, but a method in which the polymerization initiator is added in advance to the aqueous monomer solution is preferable.
【００１８】また、本発明の製法の実施にあたり、重合
前、重合時、重合後又は乾燥時等において、公知の架橋
剤を添加することができる。該架橋剤としては、例え
ば、ポリアリル化合物、ポリビニル化合物、ポリグリシ
ジルエーテル、ハロエポキシ化合物、ポリアルデヒド、
ポリオール、ポリアミン、ヒドロキシビニル化合物、ま
たカルシウム、マグネシウム、亜鉛及びアルミニウムな
どの多価イオンを生じる無機塩または有機金属塩などを
挙げることができる。In carrying out the production method of the present invention, a known crosslinking agent can be added before, during, after or during polymerization. Examples of the crosslinking agent include polyallyl compounds, polyvinyl compounds, polyglycidyl ethers, haloepoxy compounds, polyaldehydes,
Examples thereof include polyols, polyamines, hydroxyvinyl compounds, and inorganic or organic metal salts that generate polyvalent ions such as calcium, magnesium, zinc, and aluminum.
【００１９】また、逆相懸濁重合法により上記重合を終
了た後、必要に応じ通常の後処理、例えば、共沸脱水、
乾燥等を行うことにより、所望の高吸水性樹脂を得るこ
とができる。After the above polymerization is completed by the inverse suspension polymerization method, if necessary, ordinary post-treatments such as azeotropic dehydration,
By performing drying or the like, a desired superabsorbent resin can be obtained.
【００２０】本発明の製法により得られた高吸水性樹脂
は、吸水倍率が高く、しかも、含水状態での経時安定性
が良好なものであり、このため、衛生用品分野で、幼児
用、大人用もしくは失禁者用の紙おむつ（使い捨ておむ
つ）又は婦人用の生理用ナプキン等の吸収性物品におけ
る吸水性物質等として使用される。The superabsorbent resin obtained by the production method of the present invention has a high water absorption ratio and a good stability over time in a water-containing state. Used for absorbent articles such as disposable diapers (disposable diapers) for women or incontinent persons or sanitary napkins for women.
【００２１】[0021]
【実施例】以下、実施例及び比較例により本発明を更に
詳細に説明するが、本発明はこれらの実施例に限定され
るものではない。尚、特に断らない限り、以下の実施例
及び比較例における「％」は「重量％」を表す。The present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited to these examples. Unless otherwise specified, “%” in the following Examples and Comparative Examples represents “% by weight”.
【００２２】実施例及び比較例を説明するに先立ち、実
施例及び比較例で行った試験方法を以下に示す。 〔遠心脱水法による水の保持量の測定法〕高吸水性樹脂
１ｇを生理食塩水（０．９％ＮａＣｌ溶液、大塚製薬
製）１５０ｍｌで３０分間膨潤させた後、不織布袋に入
れ、遠心分離機にて１４３Ｇで１０分間脱水し、脱水後
の総重量（全体重量）を測定した。そして、下記式
（１）に従って、遠心脱水後の水の保持量を測定した。Prior to describing the examples and comparative examples, test methods performed in the examples and comparative examples are described below. [Measurement method of water retention amount by centrifugal dehydration method] After swelling 1 g of superabsorbent resin with 150 ml of physiological saline (0.9% NaCl solution, manufactured by Otsuka Pharmaceutical Co., Ltd.) for 30 minutes, put in a nonwoven bag, and centrifuge The mixture was dehydrated at 143 G for 10 minutes using a machine, and the total weight (total weight) after the dehydration was measured. Then, the retained amount of water after centrifugal dehydration was measured according to the following equation (1).
【００２３】 ここで、不織布袋液残り量＝ (遠心脱水後の不織布重
量)- (不織布袋重量)[0023] Here, non-woven bag liquid remaining amount = (weight of non-woven fabric after centrifugal dehydration)-(weight of non-woven bag)
【００２４】実施例１〜７及び比較例１〜２ 撹拌機、還流冷却器、滴下ロート、窒素ガス導入管を付
した１０００ｍｌの４つ口フラスコに、疎水性有機溶媒
としてのシクロヘキサン４００ｍｌ、及び分散剤として
のポリオキシエチレンラウリルエーテル硫酸塩（平均エ
チレンオキシド付加モル数＝２）の２５％水溶液０．８
２ｇを仕込み、窒素ガスを吹き込んで溶存酸素を追い出
し、７５℃まで昇温した。別のフラスコにて、アクリル
酸１０２．０ｇをイオン交換水２５．５ｇで希釈し、外
部より冷却しつつ、３０％水酸化ナトリウム水溶液１４
０ｇで中和した。次いで、このモノマー水溶液に、重合
開始剤としての過硫酸カリウム０．４０８ｇをイオン交
換水１３ｇに溶解させたものを添加溶解した後、窒素ガ
スを吹き込み水溶液内に残存する酸素を除去した。この
時のモノマー水溶液中のモノマー濃度は４４．５％であ
った。このモノマー水溶液をイオン交換水で希釈して、
下記〔表１〕に示す方法により、該モノマー水溶液を４
つ口フラスコ中へ添加し、温度７５℃で、６０分間モノ
マーの重合を行った。重合終了後、脱水管を用いて共沸
脱水を行い、高吸水性樹脂の含水量を高吸水性樹脂１０
０重量部に対して４０重量部に調整した。その後、架橋
剤としてのポリグリセロールポリグリシジルエーテル
（ナガセ化成工業（株）製、商品名；デナコールＥＸ−
５１２）０．１ｇを水２ｇに溶解したものを添加し、７
５〜８０℃で２時間反応させた。その後、更に共沸脱水
を行い、高吸水性樹脂の含水量を高吸水性樹脂１００重
量部に対して３０重量部に調整した。冷却後、シクロヘ
キサンをデカンテーションで除き、８０〜１００℃、約
５０Ｔｏｒｒの条件で乾燥させることにより高吸水性樹
脂を得た。得られた高吸水性樹脂の遠心脱水法による保
持量を測定した。その結果を下記〔表１〕に示す。Examples 1 to 7 and Comparative Examples 1 and 2 400 ml of cyclohexane as a hydrophobic organic solvent was dispersed in a 1000 ml four-necked flask equipped with a stirrer, a reflux condenser, a dropping funnel and a nitrogen gas inlet tube. 25% aqueous solution of polyoxyethylene lauryl ether sulfate (average number of moles of ethylene oxide added = 2) 0.8
2 g was charged, and dissolved oxygen was driven out by blowing nitrogen gas, and the temperature was raised to 75 ° C. In another flask, 102.0 g of acrylic acid was diluted with 25.5 g of ion-exchanged water, and while cooling from the outside, 30% aqueous solution of sodium hydroxide 14
Neutralized with 0 g. Next, a solution obtained by dissolving 0.408 g of potassium persulfate as a polymerization initiator in 13 g of ion-exchanged water was added and dissolved in the aqueous monomer solution, and nitrogen gas was blown thereinto to remove oxygen remaining in the aqueous solution. At this time, the monomer concentration in the aqueous monomer solution was 44.5%. This monomer aqueous solution is diluted with ion-exchanged water,
According to the method shown in Table 1 below, the monomer aqueous solution was
The mixture was added into a one-necked flask, and the monomer was polymerized at a temperature of 75 ° C. for 60 minutes. After completion of the polymerization, azeotropic dehydration is performed using a dehydration tube to reduce the water content of the superabsorbent resin to 10
The amount was adjusted to 40 parts by weight with respect to 0 parts by weight. Thereafter, polyglycerol polyglycidyl ether (trade name; manufactured by Nagase Kasei Kogyo Co., Ltd .; trade name: Denacol EX-) as a crosslinking agent
512) A solution prepared by dissolving 0.1 g in 2 g of water is added.
The reaction was performed at 5-80 ° C for 2 hours. Thereafter, azeotropic dehydration was further performed to adjust the water content of the superabsorbent resin to 30 parts by weight based on 100 parts by weight of the superabsorbent resin. After cooling, cyclohexane was removed by decantation, and dried at 80 to 100 ° C. and about 50 Torr to obtain a superabsorbent resin. The amount of the obtained superabsorbent resin was measured by a centrifugal dehydration method. The results are shown in Table 1 below.
【００２５】[0025]
【表１】 [Table 1]
【００２６】[0026]
【発明の効果】本発明によれば、高吸水性樹脂が、特別
な成分を添加したり、特殊な添加方法を行うことなく、
再現よく得られる。しかも、特定の添加方法によって水
の添加量を極少量に抑えることが可能であるため、得ら
れた高吸水性樹脂の経時安定性が損なわれない。According to the present invention, the superabsorbent resin can be used without adding a special component or performing a special addition method.
Good reproduction. In addition, since the amount of water added can be suppressed to an extremely small amount by a specific addition method, the stability with time of the obtained superabsorbent resin is not impaired.
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.6 識別記号 ＦＩ // Ｃ０８Ｆ 20/06 Ａ６１Ｆ 13/18 ３０７Ａ ──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. 6 Identification code FI // C08F 20/06 A61F 13/18 307A
Claims (2)
という）水溶液を、疎水性有機溶媒を含有する分散媒中
へ供給し、逆相懸濁重合して高吸水性樹脂を得るに際
し、 モノマー全体量の５０重量％が上記分散媒中へ供給され
る迄の該分散媒中への供給モノマー水溶液のモノマー最
低濃度（ａ1 重量％）と、これ以降の該分散媒中への供
給モノマー水溶液のモノマー最低濃度（ａ2 重量％）と
を比較したとき、ａ1 ＜ａ2 であることを特徴とする高
吸水性樹脂の製法。An aqueous solution of a water-soluble vinyl monomer (hereinafter, referred to as a monomer) is supplied into a dispersion medium containing a hydrophobic organic solvent, and subjected to reverse phase suspension polymerization to obtain a superabsorbent polymer. The minimum monomer concentration (a 1 % by weight) of the aqueous monomer solution supplied to the dispersion medium until 50% by weight of the monomer is supplied to the dispersion medium, and the subsequent monomer concentration of the aqueous monomer solution supplied to the dispersion medium when comparing the minimum density (a 2 wt%), preparation of superabsorbent polymer, which is a a 1 <a 2.
重合する請求項１記載の高吸水性樹脂の製法。2. The method for producing a superabsorbent resin according to claim 1, wherein the reverse suspension polymerization is carried out in the presence of an ionic surfactant.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP07870598A JP3871434B2 (en) | 1998-03-26 | 1998-03-26 | Production method of super absorbent resin |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP07870598A JP3871434B2 (en) | 1998-03-26 | 1998-03-26 | Production method of super absorbent resin |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH11279207A true JPH11279207A (en) | 1999-10-12 |
| JP3871434B2 JP3871434B2 (en) | 2007-01-24 |
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ID=13669290
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP07870598A Expired - Fee Related JP3871434B2 (en) | 1998-03-26 | 1998-03-26 | Production method of super absorbent resin |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7196139B2 (en) | 2002-12-26 | 2007-03-27 | Nippon Shokubai Co., Ltd. | Water-absorbent resin composition |
| WO2012023433A1 (en) * | 2010-08-19 | 2012-02-23 | 住友精化株式会社 | Water-absorbing resin |
| WO2012053121A1 (en) * | 2010-10-18 | 2012-04-26 | 住友精化株式会社 | Method for producing water-absorbent resin particles and water-absorbent resin particles |
| JP2016216713A (en) * | 2015-05-14 | 2016-12-22 | 株式会社日本触媒 | Manufacturing method of water-absorbing resin |
-
1998
- 1998-03-26 JP JP07870598A patent/JP3871434B2/en not_active Expired - Fee Related
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7196139B2 (en) | 2002-12-26 | 2007-03-27 | Nippon Shokubai Co., Ltd. | Water-absorbent resin composition |
| WO2012023433A1 (en) * | 2010-08-19 | 2012-02-23 | 住友精化株式会社 | Water-absorbing resin |
| CN103080140A (en) * | 2010-08-19 | 2013-05-01 | 住友精化株式会社 | Water-absorbing resin |
| JPWO2012023433A1 (en) * | 2010-08-19 | 2013-10-28 | 住友精化株式会社 | Water absorbent resin |
| JP5901524B2 (en) * | 2010-08-19 | 2016-04-13 | 住友精化株式会社 | Water absorbent resin |
| WO2012053121A1 (en) * | 2010-10-18 | 2012-04-26 | 住友精化株式会社 | Method for producing water-absorbent resin particles and water-absorbent resin particles |
| US20130260151A1 (en) * | 2010-10-18 | 2013-10-03 | Sumitomo Seika Chemicals Co., Ltd. | Method for producing water-absorbent resin particles and water-absorbent resin particles |
| US8951637B2 (en) * | 2010-10-18 | 2015-02-10 | Sumitomo Seika Chemicals Co., Ltd. | Method for producing water-absorbent resin particles and water-absorbent resin particles |
| JP2016216713A (en) * | 2015-05-14 | 2016-12-22 | 株式会社日本触媒 | Manufacturing method of water-absorbing resin |
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| Publication number | Publication date |
|---|---|
| JP3871434B2 (en) | 2007-01-24 |
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