JP2901368B2 - Method for producing salt-resistant water-absorbent resin - Google Patents
Method for producing salt-resistant water-absorbent resinInfo
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- JP2901368B2 JP2901368B2 JP9521591A JP9521591A JP2901368B2 JP 2901368 B2 JP2901368 B2 JP 2901368B2 JP 9521591 A JP9521591 A JP 9521591A JP 9521591 A JP9521591 A JP 9521591A JP 2901368 B2 JP2901368 B2 JP 2901368B2
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- Prior art keywords
- water
- absorbent resin
- salt
- weight
- monomer component
- Prior art date
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Description
【０００１】[0001]
【産業上の利用分野】本発明は、耐塩性吸水性樹脂の製
造方法に関するものである。詳しく述べると、ゲル強度
が高くかつ耐塩性が改良された吸水性樹脂の製造方法に
関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a salt-resistant water-absorbing resin. More specifically, the present invention relates to a method for producing a water-absorbent resin having high gel strength and improved salt resistance.
【０００２】[0002]
【従来の技術】吸水性樹脂は従来から、おむつ、生理用
品、土壌保水剤、シール剤をはじめとする各種吸水材料
に利用されている。2. Description of the Related Art Conventionally, water-absorbing resins have been used for various water-absorbing materials such as diapers, sanitary products, soil water retention agents, sealants and the like.
【０００３】このような吸水性樹脂としてはカルボキシ
ル基等の電解質構造を有するものと、ノニオン性の親水
性セグメントを有するものに大別され、前者としては例
えばアクリル酸（塩）重合体の架橋体（特開昭５５−８
４，３０４号公報等）、澱粉−アクリロニトリルグラフ
ト共重合体の加水分解物（特公昭４９−４３，３９５号
公報）、澱粉−アクリル酸のグラフト共重合体の中和物
（特公昭５３−４６，１９９号公報）、アクリル酸エス
テル−酢酸ビニル共重合体のケン化物（特公昭５３−１
３，４９５号公報）が、後者としては架橋ポリビニルア
ルコール変性物（特開昭５４−２００９３号公報）、ポ
リエチレンオキサイド部分架橋物（特開昭６１−１３
０，３２４号公報）等が知られている。[0003] Such water-absorbing resins are roughly classified into those having an electrolyte structure such as a carboxyl group and those having a nonionic hydrophilic segment. The former is, for example, a crosslinked polymer of acrylic acid (salt) polymer. (JP-A-55-8
No. 4,304), a hydrolyzate of a starch-acrylonitrile graft copolymer (JP-B-49-43395), and a neutralized product of a starch-acrylic acid graft copolymer (JP-B-53-46). 199), a saponified acrylate-vinyl acetate copolymer (Japanese Patent Publication No. 53-1).
No. 3,495), but as the latter, a cross-linked polyvinyl alcohol-modified product (Japanese Patent Application Laid-Open No. 54-20093) and a polyethylene oxide partially cross-linked product (Japanese Patent Application Laid-Open No.
No. 0,324) is known.
【０００４】吸水性樹脂は、その特質から種々の水溶液
を吸収させる目的で幅広く産業分野に使用されている
が、吸収させる液の種類によっては吸収倍率が非常に異
なり、例えば、おむつに使用した場合には、尿中の塩濃
度の変化により吸収倍率が変化して品質のフレにつなが
ったり、塩濃度により膨潤体積が変化するため、農園芸
分野や止水剤の分野での用途が制限される場合があっ
た。[0004] Water-absorbing resins are widely used in the industrial field for the purpose of absorbing various aqueous solutions because of their properties. However, the absorption capacity varies greatly depending on the type of liquid to be absorbed. In some cases, the absorption capacity changes due to changes in the urine salt concentration, leading to quality fluctuations, and the swelling volume changes depending on the salt concentration, which limits its use in the agricultural and horticultural fields and the waterproofing agent field. There was a case.
【０００５】例えば、前者のカルボキシ基等の電解質構
造を有する吸水性樹脂は一般にゲル強度が高く、かつ純
水（脱イオン水）等では非常に高い吸収倍率を示すもの
の、食塩等の電解質を有する溶液に対しては吸収倍率が
著しく低下し、いわゆる耐塩性が低いという問題点があ
る。For example, the former water-absorbent resin having an electrolyte structure such as a carboxy group generally has a high gel strength and a very high absorption capacity in pure water (deionized water) or the like, but has an electrolyte such as salt. There is a problem that the absorption capacity of the solution is remarkably reduced, and so-called salt resistance is low.
【０００６】後者のノニオン性親水性セグメントを有す
る吸水性樹脂は電解質溶液に対する吸収倍率の低下は小
さく、耐塩性という面では優れているが、ゲル強度が弱
く、吸水速度もおそく、吸収倍率の絶対値も低いもので
ある。The latter water-absorbent resin having a nonionic hydrophilic segment has a small decrease in absorption capacity with respect to an electrolyte solution and is excellent in salt resistance, but has a low gel strength, a low water absorption rate, and an absolute absorption capacity. The values are also low.
【０００７】また、耐塩性の優れた樹脂として、強電改
質であるスルホン酸基を導入した吸水性樹脂（特開昭６
１−３６，３０９号公報、特開昭５６−１６１，４１２
号公報）も知られているが、多価イオンを含んだ液に対
しては優れた耐塩性を発揮するが、一価イオンを含んだ
液に対してはアクリル酸塩架橋体等と同様に耐塩性に劣
ったものである。しかも、原料にスルホン酸基を有する
モノマーを使うため高価である。Further, as a resin having excellent salt resistance, a water-absorbing resin into which a sulfonic acid group which is a strong electric property modification is introduced (Japanese Patent Laid-Open No.
No. 1-36,309, JP-A-56-161412.
Is known, but exhibits excellent salt resistance to liquids containing polyvalent ions, but to liquids containing monovalent ions in the same manner as crosslinked acrylates etc. It is poor in salt resistance. Moreover, it is expensive because a monomer having a sulfonic acid group is used as a raw material.
【０００８】[0008]
【発明が解決しようとする課題】したがって本発明の目
的は、耐塩性吸水性樹脂の製造方法を提供することにあ
る。Accordingly, an object of the present invention is to provide a method for producing a salt-resistant water-absorbent resin.
【０００９】本発明の他の目的は、ゲル強度が大きく、
かつ吸収させる水溶液の塩濃度による吸収倍率の変化が
小さい耐塩性に優れた吸水性樹脂を安価に製造する方法
を提供することにある。Another object of the present invention is to increase the gel strength,
It is another object of the present invention to provide a method for inexpensively producing a water-absorbing resin having excellent salt resistance, which has a small change in absorption capacity depending on the salt concentration of an aqueous solution to be absorbed.
【００１０】[0010]
【課題を解決するための手段】上記諸目的は、不飽和カ
ルボン酸およびその塩よりなる群から選ばれた少なくと
も１種の単量体成分（Ａ）の水溶液と、不飽和カルボン
酸およびその塩よりなる群から選ばれた少なくとも１種
の単量体成分を水溶液重合することによって得られる吸
水性樹脂（Ｂ）とを、前記単量体成分（Ａ）１００重量
部当たり、前記吸水性樹脂（Ｂ）１〜３０重量部の割合
で存在させて水溶液重合することよりなる耐塩性吸水性
樹脂の製造方法により達成される。Means for Solving the Problems] objects mentioned above includes an aqueous solution of at least one monomer component selected from unsaturated carboxylic acids and the group consisting of a salt thereof (A), the unsaturated carboxylic
At least one selected from the group consisting of acids and salts thereof
Aqueous solution obtained by aqueous polymerization of monomer components
The aqueous resin (B) is mixed with the monomer component (A) in an amount of 100% by weight.
This is achieved by a method for producing a salt-resistant water-absorbent resin , which comprises presenting the water-absorbent resin (B) in an amount of 1 to 30 parts by weight per part and polymerizing the aqueous solution.
【００１１】[0011]
【作用】本発明の製造方法による得られる耐塩性吸水性
樹脂は、耐塩性、ゲル強度が、ともに著しく優れてい
る。また本発明においては得られた耐塩性吸水性樹脂中
に含まれる特定粒度範囲の樹脂をさらに吸水性樹脂
（Ｂ）として繰り返し用いることもでき、例えば細かい
粒度範囲の樹脂を吸水性樹脂（Ｂ）として用いた場合に
は得られた製品は、例えば１４９μｍ以下の微粉の混在
量が著しく低減され、吸収諸特性、経済性にも優れたも
のとなるばかりでなく、これを用いて紙おむつ、生理綿
等の各種吸収物品に加工する際に微粉が飛散する心配も
なく、労働衛生の面での問題も解消するという利点をも
有するものである。したがって、本発明により得られる
耐塩性吸水性樹脂は、その特性を生かし、おむつ、生理
用品、農園芸用、シール剤、推進工法用滑剤、地盤掘削
における逸泥防止、泥水の固定剤、カーペット下敷、農
業用被覆剤等に有効に使用できる。The salt-resistant water-absorbing resin obtained by the production method of the present invention has remarkably excellent salt resistance and gel strength. Further, in the present invention, a resin having a specific particle size range contained in the obtained salt-resistant water-absorbent resin can be used repeatedly as the water-absorbent resin (B). For example, a resin having a fine particle size range can be used as the water-absorbent resin (B). When used as a product, not only is the resulting product significantly reduced in the amount of fine powder of, for example, 149 μm or less, and is not only excellent in absorption characteristics and economical efficiency, but also can be used in disposable diapers and menstrual cotton. There is also an advantage that there is no fear that fine powder is scattered when processing into various absorbent articles such as, for example, and that problems in terms of occupational health can be solved. Therefore, the salt-resistant water-absorbent resin obtained by the present invention, taking advantage of its properties, diapers, sanitary products, agricultural and horticultural use, sealants, lubricants for propulsion methods, soil loss prevention in ground excavation, muddy water fixing agent, carpet underlay , Can be effectively used for agricultural coatings and the like.
【００１２】本発明に用いられる不飽和カルボン酸とし
ては、例えば（メタ）アクリル酸、クロトン酸、イタコ
ン酸、マレイン酸、フマル酸、シトラコン酸等が、また
不飽和カルボン酸の塩としては、これらのアルカリ金属
塩、アンモニウム塩のおよび置換アンモニウム塩等を挙
げることができ、これらの中から１種または２種以上を
用いることができる。The unsaturated carboxylic acids used in the present invention include, for example, (meth) acrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, citraconic acid and the like. And substituted ammonium salts, etc. of these, and one or more of these can be used.
【００１３】ただし、耐塩性が優れた吸水性樹脂を得る
ために、不飽和カルボン酸および／またはその塩として
アクリル酸および／またはアクリル酸塩を必須成分とし
て用いるのが好ましい。特にアクリル酸１０〜７０モル
％、好ましくは２０〜４０モル％およびアクリル酸塩９
０〜３０モル％、好ましくは８０〜６０モル％よりなる
ものが好ましい。However, in order to obtain a water-absorbent resin having excellent salt resistance, it is preferable to use acrylic acid and / or acrylate as an essential component as an unsaturated carboxylic acid and / or a salt thereof. In particular, 10 to 70 mol% of acrylic acid, preferably 20 to 40 mol% and acrylate 9
Those comprising 0 to 30 mol%, preferably 80 to 60 mol% are preferred.
【００１４】単量体成分（Ａ）には、上記不飽和カルボ
ン酸および／またはその塩以外に、他の不飽和単量体が
含まれていてもよい。The monomer component (A) may contain another unsaturated monomer in addition to the unsaturated carboxylic acid and / or its salt.
【００１５】他の不飽和単量体としては、例えば２−ア
クリルアミド−２−メチルプロパンスルホン酸、ビニル
スルホン酸、（メタ）アリルスルホン酸、スチレンスル
ホン酸、スルホエチル（メタ）アクリレート、スルホプ
ロピル（メタ）アクリレート、ビニルトルエンスルホン
酸等の不飽和スルホン酸およびそれらの塩；Ｎ，Ｎ−ジ
メチルアミノエチル（メタ）アクリレート、Ｎ，Ｎ−ジ
エチルアミノエチル（メタ）アクリレート等の不飽和ア
ミン化合物およびそれらの塩；ヒドロキシエチル（メ
タ）アクリレート、メトキシエチル（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、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、（メタ）アクリル酸メチル、（メタ）アクリル酸
エチル等の（メタ）アクリル酸エステル；（メタ）アク
リルアミド、Ｎ−ヘキシル（メタ）アクリルアミド、Ｎ
−メチロール（メタ）アクリルアミド、Ｎ，Ｎジメチル
（メタ）アクリルアミド等の不飽和アミド；スチレン、
α−メチルスチレン、ｏ−メチルスチレン、ｐ−メチル
スチレン等のスチレンまたはその誘導体；（メタ）アク
リロニトリル、酢酸ビニル等を挙げることができ、これ
らの１種、または２種以上を単量体成分（Ａ）中の５０
重量％未満、好ましくは４０重量％未満の範囲で用いる
ことができる。Other unsaturated monomers include, for example, 2-acrylamido-2-methylpropanesulfonic acid, vinylsulfonic acid, (meth) allylsulfonic acid, styrenesulfonic acid, sulfoethyl (meth) acrylate, sulfopropyl (meth) ) Unsaturated sulfonic acids such as acrylate and vinyltoluenesulfonic acid and salts thereof; unsaturated amine compounds such as N, N-dimethylaminoethyl (meth) acrylate and N, N-diethylaminoethyl (meth) acrylate and salts thereof ; Hydroxyethyl (meth) acrylate, methoxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, methoxypolyethylene glycol (Meth) acrylic esters such as mono (meth) acrylate, methoxypolypropylene glycol mono (meth) acrylate, methyl (meth) acrylate and ethyl (meth) acrylate; (meth) acrylamide, N-hexyl (meth) acrylamide, N
Unsaturated amides such as methylol (meth) acrylamide, N, N dimethyl (meth) acrylamide; styrene,
Styrene such as α-methylstyrene, o-methylstyrene, p-methylstyrene or a derivative thereof; (meth) acrylonitrile, vinyl acetate and the like. One or more of these may be used as a monomer component ( A) 50 of
It can be used in a range of less than 40% by weight, preferably less than 40% by weight.
【００１６】本発明に用いられる吸水性樹脂（Ｂ）は吸
水して含水ゲル状物となり得る水不溶性樹脂で、例えば
アクリル酸エステル−酢酸ビニル共重合架橋体のケン化
物、部分中和（メタ）アクリル酸重合体の架橋体等が挙
げられる。[0016] used in the present invention water-absorbent resin (B) in water to hydrated gel product capable of becoming water-insoluble resin, in example Example
A acrylic acid ester - a saponified vinyl acetate copolymer crosslinked, parts partial neutralization (meth) include crosslinked product of acrylic acid polymers.
【００１７】好ましくは、部分中和（メタ）アクリル酸
重合体の架橋体で、例えば特開昭５６−９３，７１６号
公報、特開昭５６−１３１，６０８号公報、特開昭５６
−１４７，８０６号公報、特開昭５８−７１９０７号公
報、特開昭５８−１１７，２２２号公報、特公昭５４−
３０，７１０号公報、特公昭５４−３７，９９４号公
報、特公昭５３−４６，２００号公報、米国特許第４，
０４１，２２８号公報で開示されていた吸水能が１００
〜１０００倍の吸水性樹脂等は、いずれも本発明の吸水
性樹脂（Ｂ）として好ましく利用できる。中でも、単量
体成分を均一に吸収して膨潤し、ＩＰＮ構造やグラフト
化を効率よく起こして優れた耐塩性吸水性樹脂を得るた
めに、吸水性樹脂（Ｂ）としては、含水率が０．１〜１
０重量％の粉末状のものが好ましい。また、単量体成分
（Ａ）の吸水を速やかに起こさせるためにも、吸水性樹
脂（Ｂ）は、その９０〜１００重量％が１〜１４９μ
ｍ、特に１〜７４μｍの粒子径を有するが好ましい。Preferably, it is a crosslinked product of a partially neutralized (meth) acrylic acid polymer, for example, JP-A-56-93716, JP-A-56-131,608, JP-A-56-131,608.
-147,806, JP-A-58-71907, JP-A-58-117,222, and JP-B-54-117,222.
No. 30,710, JP-B-54-37,994, JP-B-53-46,200, U.S. Pat.
No. 041,228, the water absorption capacity is 100.
Any water-absorbent resin of up to 1000 times can be preferably used as the water-absorbent resin (B) of the present invention. Above all, in order to uniformly absorb and swell the monomer components and to efficiently cause an IPN structure and grafting to obtain an excellent salt-resistant water-absorbent resin, the water-absorbent resin (B) has a water content of 0%. .1 to 1
A powder of 0% by weight is preferred. Further, in order to promptly cause water absorption of the monomer component (A), 90 to 100% by weight of the water-absorbing resin (B) is 1 to 149 μm.
m, particularly preferably 1 to 74 μm.
【００１８】吸水性樹脂（Ｂ）を構成するもとの単量体
成分（Ａ）は、同じであっても異なっていてもよいが、
最終的に得られる吸水性樹脂の物性や後述するように、
本発明の操作を繰り返す場合を考えると、同一組成であ
ることが好ましい。また、吸水性樹脂（Ｂ）を得るため
の重合方法も、水溶液重合であっても、その他の重合方
法であってもよいが、同じく本発明の操作を繰り返す場
合を考えると、水溶液重合であることが好ましい。ま
た、前記不飽和カルボン酸の重合体を、そのカルボキシ
ル基が０．３〜０．９当量、好ましくは、０．６〜０．
８当量中和されてなるものであってもよい。このような
吸水性樹脂（Ｂ）としては、通常の製法により得られる
吸水性樹脂、または必要により特定粒度範囲を選んだ吸
水性樹脂を用いてもよく、市販の吸水性樹脂製品を当事
者に周知の粉砕機によりさらに粉砕して得てもよく、ま
た、本発明の製造方法の水溶液重合を行った後、乾燥、
分級して得られる耐塩性吸水性樹脂中に含まれる吸水性
樹脂（Ｂ）と同様の粒度範囲の樹脂（Ｃ）を除去し、再
度吸水性樹脂（Ｂ）として繰り返し用いてもよい。ま
た、吸水性樹脂（Ｂ）は、粒子の表面部分の架橋密度が
高められるような処理を施されたものでもよい。The monomer component (A) constituting the water-absorbent resin (B) may be the same or different.
As described below, the physical properties of the water-absorbent resin finally obtained,
Considering the case where the operation of the present invention is repeated, the same composition is preferable. Also, the polymerization method for obtaining the water-absorbent resin (B) may be aqueous solution polymerization or another polymerization method. However, considering the case where the operation of the present invention is repeated, the polymerization method is aqueous solution polymerization. Is preferred. In addition, the unsaturated carboxylic acid polymer is prepared by preparing the polymer having a carboxyl group of 0.3 to 0.9 equivalent, preferably 0.6 to 0.5 equivalent.
It may be neutralized by 8 equivalents. As such a water-absorbent resin (B), a water-absorbent resin obtained by an ordinary production method or a water-absorbent resin having a specific particle size range selected as necessary may be used. May be further pulverized by a pulverizer, and after performing aqueous solution polymerization of the production method of the present invention, drying,
The resin (C) having the same particle size range as the water-absorbent resin (B) contained in the salt-resistant water-absorbent resin obtained by the classification may be removed and used again as the water-absorbent resin (B). Further, the water-absorbent resin (B) may be subjected to a treatment for increasing the crosslink density of the surface portion of the particles.
【００１９】吸水性樹脂（Ｂ）の使用量は、耐塩性が特
に優れた吸水性樹脂を効率よく得るために、単量体成分
（Ａ）１００重量部に対して１〜３０重量部、好ましく
は５〜２０重量部である。この量が３０重量部を越す
と、単量体成分（Ａ）の中に吸水性樹脂（Ｂ）が均一に
分散膨潤し得ず、樹脂が析出した状態になり、所望とす
る吸収倍率の高い耐塩性吸水性樹脂が得られない。ま
た、１重量部未満では、本発明の意思するところの耐塩
性が発現しない。また、吸水性樹脂（Ｂ）の単量体成分
（Ａ）への添加は、単量体成分（Ａ）の重合が開始する
までに行うのが一般的であるが、重合開始後、未だ系が
流動性を保持している状態であれば、この時期に吸水性
樹脂（Ｂ）を添加することもできる。The amount of the water-absorbing resin (B) used is preferably 1 to 30 parts by weight, preferably 100 parts by weight of the monomer component (A), in order to efficiently obtain a water-absorbing resin having particularly excellent salt resistance. Is 5 to 20 parts by weight. When this amount exceeds 30 parts by weight, the water-absorbent resin (B) cannot be uniformly dispersed and swollen in the monomer component (A), and the resin is in a precipitated state, and the desired absorption capacity is high. A salt-resistant water-absorbent resin cannot be obtained. If the amount is less than 1 part by weight, the salt resistance intended by the present invention is not exhibited. The addition of the water-absorbent resin (B) to the monomer component (A) is generally performed before the polymerization of the monomer component (A) starts. As long as the resin retains fluidity, the water-absorbent resin (B) can be added at this time.
【００２０】本発明の製造方法によれば、架橋剤を用い
ずに単量体成分（Ａ）を吸水性樹脂（Ｂ）の存在下で水
溶液重合するだけでも、該単量体成分（Ａ）が該吸収性
樹脂（Ｂ）にグラフトまたはＩＰＮ構造をとりながら重
合するために、耐塩性吸水性樹脂を得ることができると
推測されるが、更に、ゲル強度がよりすぐれた吸水性樹
脂を得るために、重合時単量体成分（Ａ）に架橋剤を配
分しておくのが好ましい。According to the production method of the present invention, the monomer component (A) can be polymerized in the aqueous solution in the presence of the water-absorbent resin (B) without using a crosslinking agent. Is presumed to be able to obtain a salt-resistant water-absorbent resin because it is polymerized while having a graft or IPN structure on the absorbent resin (B). For this reason, it is preferable to distribute a crosslinking agent to the monomer component (A) during polymerization.
【００２１】本発明に用いることができる架橋剤として
は、例えばエチレングリコールジ（メタ）アクリレー
ト、ジエチレングリコールジ（メタ）アクリレート、ト
リエチレングリコールジ（メタ）アクリレート、プロピ
レングリコールジ（メタ）アクリレート、ポリエチレン
グリコールジ（メタ）アクリレート、トリメチロールプ
ロパントリ（メタ）アクリレート、ペンタエリスリトー
ルトリ（メタ）アクリレート、ペンタエリスリトールジ
（メタ）アクリレート、Ｎ，Ｎ´−メチレンビス（メ
タ）アクリルアミド、イソシアヌル酸トリアリル、トリ
メチロールプロパンジ（メタ）アリルエーテル等の１分
子中にエチレン性不飽和基を２個以上有する化合物；エ
チレングリコール、ジエチレングリコール、トリエチレ
ングリコール、ポリエチレングリコール、グリセリン、
ポリグリセリン、プロピレングリコール、ジエタノール
アミン、トリジエタノールアミン、ポリプロピレングリ
コール、ポリビニルアルコール、ペンタエリスリトー
ル、ソルビット、ソルビタン、グルコース、マンニッ
ト、マンニタン、ショ糖、ブドウ糖などの多価アルコー
ル；エチレングリコールジグリシジルエーテル、ポリエ
チレングリコールジグリシジルエーテル、グリセリント
リグリシジルエーテル等のポリグリシジルエーテル；エ
ピクロルヒドリン、α−メチルクロルヒドリン等のハロ
エポキシ化合物；グルタールアルデヒド、グリオキザー
ル等のポリアルデヒド；エチレンジアミン等のポリアミ
ン類；水酸化カルシウム、塩化カルシウム、炭酸カルシ
ウム、酸化カルシウム、塩化硼砂マグネシウム、酸化マ
グネシウム、塩化アルミニウム、塩化亜鉛および塩化ニ
ッケル等の周期律表２Ａ族、３Ｂ族、８族の金属の水酸
化物、ハロゲン化物、炭酸塩、酸化物、硼砂等の硼酸
塩、アルミニウムイソプロピラート等の多価金属化合物
等が挙げられ、これらの１種または２種以上を、反応性
を考慮した上で適宜選んで用いることができるが、１分
子中にエチレン性不飽和基を２個以上有する化合物を架
橋剤として用いるのが最も好ましい。Examples of the crosslinking agent that can be used in the present invention include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, and polyethylene glycol. Di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol di (meth) acrylate, N, N'-methylenebis (meth) acrylamide, triallyl isocyanurate, trimethylolpropanedi Compounds having two or more ethylenically unsaturated groups in one molecule such as (meth) allyl ether; ethylene glycol, diethylene glycol, triethylene glycol, polyether Glycol, glycerin,
Polyglycerol, propylene glycol, diethanolamine, tridiethanolamine, polypropylene glycol, polyvinyl alcohol, pentaerythritol, sorbitol, sorbitan, polyhydric alcohols such as glucose, mannitol, mannitol, sucrose, glucose, etc .; ethylene glycol diglycidyl ether, polyethylene glycol di Polyglycidyl ethers such as glycidyl ether and glycerin triglycidyl ether; haloepoxy compounds such as epichlorohydrin and α-methylchlorohydrin; polyaldehydes such as glutaraldehyde and glyoxal; polyamines such as ethylenediamine; calcium hydroxide, calcium chloride, and carbonic acid Calcium, calcium oxide, magnesium borax chloride, magnesium oxide, aluminum chloride Hydroxides, halides, carbonates, oxides, borates such as borax, and polyvalent metals such as aluminum isopropylate of metals of Groups 2A, 3B and 8 of the periodic table such as chromium, zinc chloride and nickel chloride And the like. One or more of these compounds can be appropriately selected and used in consideration of reactivity, but a compound having two or more ethylenically unsaturated groups in one molecule is used as a crosslinking agent. It is most preferred to use
【００２２】これらの架橋剤は必要かつ充分な効果を発
現させるために単量体成分（Ａ）に対して０．００１〜
０．１モル％、特に好ましくは０．０１〜０．０５モル
％の量で用いるのがより好ましい。０．１モル％を越え
ると吸収倍率自体の低下を招く場合があるので注意を要
する。These crosslinking agents are used in an amount of 0.001 to 0.01% based on the amount of the monomer component (A) in order to exhibit necessary and sufficient effects.
More preferably, it is used in an amount of 0.1 mol%, particularly preferably 0.01 to 0.05 mol%. Care must be taken because if it exceeds 0.1 mol%, the absorption capacity itself may decrease.
【００２３】本発明においてはその重合方法として水溶
性重合を用いることが必須である。他の重合法、例えば
逆相懸濁重合、噴霧重合、沈殿重合等では、単量体成分
（Ａ）中に吸水性樹脂（Ｂ）が安定に分散して均一に存
在し得ず、本発明の意思する耐塩性の効果は得られな
い。In the present invention, it is essential to use water-soluble polymerization as the polymerization method. In other polymerization methods such as reverse phase suspension polymerization, spray polymerization and precipitation polymerization, the water-absorbent resin (B) is stably dispersed in the monomer component (A) and cannot be uniformly present. However, the effect of the salt resistance desired by the above is not obtained.
【００２４】また、水溶液重合は単量体成分（Ａ）中に
吸水性樹脂（Ｂ）を均一に分散し、グラフト反応等を効
率よく行わせるために、撹拌混合下に行うことが好まし
い。そのためには回転撹拌軸を有する反応容器内で該回
転撹拌軸の剪断力により、重合に伴い生成するゲル状物
を、細分化しながら重合を行うことが更に好ましく、例
えば特開昭５７−３４，１０１号公報、ＵＳ−Ａ−４，
６２５，００１およびＥＰ０３４３，９１９に開示され
ているように複数の回転撹拌軸を有する反応容器として
ニーダーを用いるのが最も好ましい。The aqueous solution polymerization is preferably carried out with stirring and mixing in order to uniformly disperse the water-absorbent resin (B) in the monomer component (A) and to efficiently carry out the grafting reaction and the like. For that purpose, it is more preferable to carry out polymerization while fragmenting a gel-like substance produced by polymerization in a reaction vessel having a rotary stirring shaft by the shearing force of the rotary stirring shaft. No. 101, US-A-4,
Most preferably, a kneader is used as a reaction vessel having a plurality of rotary stirring shafts as disclosed in 625,001 and EP 0343,919.
【００２５】重合の開始方法としては、例えばラジカル
重合開始触媒を用いる方法、活性エネルギー線を照射す
る方法等が挙げられる。ラジカル重合開始触媒として
は、例えば過酸化水素、ベンゾイルパーオキサイド等の
過酸化物；２−２´−アゾビス−２−アミジノプロパン
二塩酸塩、アゾビスイソブチロニトリル等のアゾ化合
物；過硫酸アンモニウム、過硫酸カリウム、過硫酸ナト
リウム等の過硫酸塩等のラジカル発生剤や、これらラジ
カル発生剤と亜硫酸水素ナトリウム、Ｌ−アスコルビン
酸、第一鉄塩等の還元剤との組み合わせによるレドック
ス系開始剤などが用いられる。その使用量は、単量体成
分（Ａ）に対して０．０１〜１．０重量％、好ましくは
０．０５〜０．５重量％である。水溶液重合するに際し
て、重合用溶媒としては水だけを用いるのが好ましい
が、必要によりメタノール、エタノール、イソプロパノ
ール、アセトン、ジメチルホルムアミド、ジメチルスル
ホキシド等の親水性有機溶剤を水に添加して用いてもよ
い。Examples of the polymerization initiation method include a method using a radical polymerization initiation catalyst, a method of irradiating with an active energy ray, and the like. Examples of the radical polymerization initiation catalyst include peroxides such as hydrogen peroxide and benzoyl peroxide; azo compounds such as 2-2'-azobis-2-amidinopropane dihydrochloride and azobisisobutyronitrile; ammonium persulfate; Radical generators such as persulfates such as potassium persulfate and sodium persulfate, and redox initiators obtained by combining these radical generators with reducing agents such as sodium bisulfite, L-ascorbic acid and ferrous salts. Is used. The amount used is 0.01 to 1.0% by weight, preferably 0.05 to 0.5% by weight, based on the monomer component (A). In the case of aqueous solution polymerization, it is preferable to use only water as a polymerization solvent, but if necessary, a hydrophilic organic solvent such as methanol, ethanol, isopropanol, acetone, dimethylformamide, or dimethylsulfoxide may be added to water and used. .
【００２６】水溶液重合時の単量体成分（Ａ）の濃度は
特に制限されずに広い範囲とすることができるが、重合
反応の制御の容易さや、収率を考慮すれば、単量体成分
（Ａ）：水の比率を１：９〜７：３（重量比）、特に
３：７〜５：５の範囲とするのが好ましい。The concentration of the monomer component (A) at the time of the aqueous solution polymerization is not particularly limited, and can be in a wide range. However, considering the ease of controlling the polymerization reaction and the yield, the monomer component (A) can be used. The ratio of (A): water is preferably in the range of 1: 9 to 7: 3 (weight ratio), particularly preferably in the range of 3: 7 to 5: 5.
【００２７】本発明において耐塩性とは、吸収させる水
溶液中の塩濃度における、吸収倍率の変化の程度が少な
いことを意味し、耐塩性＝生理食塩水の吸収倍率／純水
（脱イオン水）の吸収倍率と定義される。In the present invention, the salt resistance means that the degree of change in the absorption capacity is small in the salt concentration in the aqueous solution to be absorbed. Salt resistance = absorption capacity of physiological saline / pure water (deionized water) Is defined as the absorption capacity of
【００２８】吸水性樹脂の耐塩性が向上すると、例えば
紙おむつや生理用品中の吸収剤に用いた場合には、尿中
の塩濃度の影響をうけにくく、安定した吸収倍率を有し
液体の吸収性に優れたものとなり、また、海水等のシー
ル剤に用い場合には、シール効果が塩濃度によって影響
され難くなる利点がある。When the salt resistance of the water-absorbent resin is improved, for example, when used as an absorbent in disposable diapers and sanitary articles, the water-absorbent resin is hardly affected by the salt concentration in urine, has a stable absorption capacity, and absorbs liquid. In addition, when used as a sealant for seawater or the like, there is an advantage that the sealing effect is less likely to be affected by the salt concentration.
【００２９】[0029]
【実施例】以下、実施例により本発明を詳細に説明する
が、本発明の範囲はこれらの実施例によって何ら制限さ
れるものではない。EXAMPLES The present invention will be described in detail below with reference to examples, but the scope of the present invention is not limited by these examples.
【００３０】耐塩性吸水性樹脂の吸収倍率、ゲル強度
は、次に示す方法により測定した。The absorption capacity and gel strength of the salt-resistant water-absorbent resin were measured by the following methods.
【００３１】（１）純水（脱イオン水）の吸収倍率；耐
塩性吸水性樹脂約０．０５ｇを不織布製のティーバッグ
式袋（４０ｍｍ×１５０ｍｍ）に均一に入れ、大過剰の
純水（脱イオン水）に３０分間浸漬し、引き上げてペー
パー上で水切りを行い、吸液後の重量を測定した。空の
ティーバッグ式袋自体を同様の手順で吸液した時の重量
をブランクとして、次式にしたがって純水（脱イオン
水）の吸収倍率を算出した。純水（脱イオン水）の吸収
倍率(g/g)=( 吸液後の重量g-ブランクg)/(耐塩性樹脂の
重量g) （２）生理食塩水の吸収倍率；耐塩性吸水性樹脂約０．
２ｇを不織布製のティーバッグ式袋（４０ｍｍ×１５０
ｍｍ）に均一に入れ、大過剰の生理食塩水（０．９重量
％ＮａＣｌ）に３０分間浸漬し膨潤させ、引き上げてペ
ーパー上で水切りをし、吸液後の重量を測定した。空の
ティーバッグ式袋自体を同様の手順で吸液した時の重量
をブランクとして、次式にしたがって純水の吸収倍率を
算出した。(1) Absorption capacity of pure water (deionized water): About 0.05 g of salt-resistant water-absorbent resin is uniformly placed in a non-woven tea bag type bag (40 mm × 150 mm), and a large excess of pure water ( (Deionized water) for 30 minutes, pulled up and drained on paper, and the weight after liquid absorption was measured. The absorption capacity of pure water (deionized water) was calculated according to the following equation, using the weight when the empty tea bag type bag itself was absorbed in the same procedure as the blank as a blank. Absorption capacity of pure water (deionized water) (g / g) = (weight after absorption-blank g) / (weight of salt-resistant resin) (2) Absorption capacity of physiological saline; salt-resistant water absorption Resin about 0.
2 g of a non-woven tea bag type bag (40 mm × 150
mm), immersed in a large excess of physiological saline (0.9% by weight of NaCl) for 30 minutes to swell, pulled up and drained on paper, and the weight after liquid absorption was measured. The absorption capacity of pure water was calculated according to the following equation, using the weight when the empty tea bag type bag itself was absorbed in the same procedure as a blank as a blank.
【００３２】生理食塩水の吸収倍率(g/g)=（吸液後の重
量g-ブランクg)/(耐塩性樹脂の重量g)なお、耐塩性は、
耐塩性＝生理食塩水の吸収倍率／純水（脱イオン水）の
吸収倍率で表す。The absorption capacity of physiological saline (g / g) = (weight after absorption-blank g) / (weight of salt-resistant resin)
Salt tolerance = absorption capacity of physiological saline / absorption capacity of pure water (deionized water).
【００３３】（３）ゲル強度；膨潤ヒドロゲルを、半径
２．５ｃｍの円盤を具備する応力レオメーターにより、
試料の厚み０．１ｃｍ、振動周波数１．０Ｈｚの条件下
に測定した。膨潤ヒドロゲルの剪断弾性率をもってゲル
強度とした。なお、膨潤ヒドロゲルは、耐塩性吸水性樹
脂を人工尿（尿素 １．９重量％、ＮａＣｌ ０．８重
量％、ＣａＣｌ２ ０．１重量％、ＭｇＳＯ４ ０．１
重量％）に１時間浸漬し膨潤させた後、過剰の人工尿を
濾紙で除去することによって得た。(3) Gel strength: The swollen hydrogel was treated with a stress rheometer equipped with a disk having a radius of 2.5 cm.
The measurement was performed under the conditions of a sample thickness of 0.1 cm and a vibration frequency of 1.0 Hz. The gel strength was defined as the shear modulus of the swollen hydrogel. In addition, the swelling hydrogel was prepared by adding salt-resistant water-absorbing resin to artificial urine (urea 1.9% by weight, NaCl 0.8% by weight, CaCl 2 0.1% by weight, MgSO 4 0.1%).
(% By weight) and swelled for 1 hour, and then obtained by removing excess artificial urine with filter paper.
【００３４】実施例１羽根の回転径が１２０ｍｍのシグ
マ型羽根を２本有した内容積１０リットルのジャケット
付きステンレス製双腕型ニーダーに、アクリル酸ナトリ
ウム７５モル％およびアクリル酸２５モル％からなる単
量体成分（Ａ）の水溶液４４００ｇ（単量体成分の濃度
３７重量％）と、架橋剤としてのトリメチルメチロール
プロパンアクリレート２．７２ｇ（０．０５モル％対単
量体成分（Ａ））とを入れ、窒素ガスを吹き込んで反応
系内を窒素置換した。次いで２本のシグマ型羽根を、回
転させながら、吸水性樹脂（日本触媒化学工業株式会社
製、アクアリックＣＡ）をハンマーミルで粉砕し、１０
０メッシュの金網を通過させて得られた粒子径１〜１４
９μｍの吸水性樹脂（Ｂ）１６２ｇ（１０重量％対単量
体成分（Ａ））を入れ、ジャケットに３０℃の温水を通
すことによって反応径内を加熱しながら、開始剤として
過硫酸ナトリウム１．２０ｇと亜硫酸水素ナトリウム
１．１０ｇとを添加した。重合反応開始後更に６０分間
重合反応を続行して得られたゲル重合体は、約３ｍｍの
径の細粒に細分化されていた。得られたゲル重合体を金
網上で１５０℃の温度条件下に２時間熱風乾燥した。こ
の乾燥物をハンマーミルを用いて粉砕し、耐塩性吸水性
樹脂を得た。得られた耐塩性吸水性樹脂の性能を表１に
示す。EXAMPLE 1 A jacketed stainless-steel double-armed kneader having two sigma-type blades having a rotating diameter of 120 mm and having a volume of 10 liters was composed of 75 mol% of sodium acrylate and 25 mol% of acrylic acid. 4,400 g of an aqueous solution of the monomer component (A) (concentration of the monomer component: 37% by weight), 2.72 g of trimethylmethylolpropane acrylate (0.05 mol% relative to the monomer component (A)) as a crosslinking agent, And the inside of the reaction system was replaced with nitrogen by blowing nitrogen gas. Next, while rotating the two sigma-type blades, the water-absorbent resin (Nippon Shokubai Chemical Co., Ltd., Aquaric CA) was pulverized with a hammer mill, and
Particle size 1-14 obtained by passing through a 0 mesh wire mesh
162 g of a 9 μm water-absorbent resin (B) (10% by weight relative to the monomer component (A)) was charged, and the inside of the reaction diameter was heated by passing warm water of 30 ° C. through a jacket. .20 g and 1.10 g of sodium bisulfite were added. The gel polymer obtained by continuing the polymerization reaction for another 60 minutes after the initiation of the polymerization reaction was finely divided into fine particles having a diameter of about 3 mm. The obtained gel polymer was dried with hot air on a wire mesh at a temperature of 150 ° C. for 2 hours. The dried product was pulverized using a hammer mill to obtain a salt-resistant water-absorbent resin. Table 1 shows the performance of the obtained salt-resistant water-absorbent resin.
【００３５】実施例２実施例１において吸水性樹脂
（Ｂ）の量を４０７ｇ（２５重量％対単量体成分
（Ａ））とする以外は、実施例１と同様な操作を繰り返
して、耐塩性吸水性樹脂を得た。この耐塩性吸水性樹脂
の性能を表１に示す。Example 2 The procedure of Example 1 was repeated except that the amount of the water-absorbent resin (B) was changed to 407 g (25% by weight based on the monomer component (A)). Water-absorbent resin was obtained. Table 1 shows the performance of the salt-resistant water-absorbent resin.
【００３６】実施例３実施例２において架橋剤を用いな
かった以外は、実施例２と同様な操作を繰り返して、耐
塩性吸水性樹脂を得た。この耐塩性吸水性樹脂の性能を
表１に示す。Example 3 A salt-resistant water-absorbent resin was obtained by repeating the same operation as in Example 2 except that no crosslinking agent was used. Table 1 shows the performance of the salt-resistant water-absorbent resin.
【００３７】実施例４実施例１で用いたのと同様の双腕
型ニーダーに、アクリル酸ナトリウム２８２ｇおよびア
クリル酸１０８ｇおよびスルホエチルアクリレートのナ
トリウム塩６０６ｇからなる単量体成分（Ａ）の水溶液
２４９０ｇ（単量体成分の濃度４０重量％）と、架橋剤
としてのトリメチルメチロールプロパントリアクリレー
ト０．８８８ｇ（０．０４モル％対単量体成分（Ａ））
とを入れ、窒素ガスを吹き込んで反応系内を窒素置換し
た。次いで２本のシグマ型羽根を、それぞれ回転させな
がら、実施例１で用いた吸水性樹脂（Ｂ）９７ｇ（１０
重量％対単量体成分（Ａ））を入れ、ジャケットに３０
℃の温水を通すことによって反応系内を加熱しながら、
重合開始剤として過硫酸ナトリウム０．９ｇとＬ−アス
コルビン酸０．０３８ｇとを添加した。重合反応開始後
更に９０分間重合反応を続行して得られたゲル重合体
は、約３ｍｍの径の細粒に細分化されていた。得られた
ゲル重合体を金網上で１５０℃の温度条件下に２時間熱
風乾燥した。この乾燥物をハンマーミルを用いて粉砕
し、耐塩性吸水性樹脂を得た。得られた耐塩性吸水性樹
脂の性能を表１に示す。Example 4 A double-arm kneader similar to that used in Example 1 was charged with 2490 g of an aqueous solution of the monomer component (A) comprising 282 g of sodium acrylate, 108 g of acrylic acid and 606 g of sodium salt of sulfoethyl acrylate. (The concentration of the monomer component is 40% by weight), and 0.888 g of trimethylmethylolpropane triacrylate (0.04 mol% based on the monomer component (A)) as a crosslinking agent
And the inside of the reaction system was purged with nitrogen by blowing nitrogen gas. Next, while rotating each of the two sigma-type blades, 97 g of the water-absorbent resin (B) used in Example 1 (10
% By weight of the monomer component (A)), and 30
While heating the reaction system by passing hot water at ℃
0.9 g of sodium persulfate and 0.038 g of L-ascorbic acid were added as polymerization initiators. The gel polymer obtained by continuing the polymerization reaction for another 90 minutes after the initiation of the polymerization reaction was finely divided into fine particles having a diameter of about 3 mm. The obtained gel polymer was dried with hot air on a wire mesh at a temperature of 150 ° C. for 2 hours. The dried product was pulverized using a hammer mill to obtain a salt-resistant water-absorbent resin. Table 1 shows the performance of the obtained salt-resistant water-absorbent resin.
【００３８】実施例５実施例４において架橋剤を用いな
かった以外は、実施例４と同様な操作を繰り返して、耐
塩性吸水性樹脂を得た。この耐塩性吸水性樹脂の性能を
表１に示す。実施例６実施例４において吸水性樹脂
（Ｂ）の量を４９．８ｇ（５重量％対単量体成分
（Ａ））とする以外は、実施例４と同様な操作を繰り返
して、耐塩性吸水性樹脂を得た。この耐塩性吸水性樹脂
の性能を表１に示す。Example 5 A salt-resistant water-absorbent resin was obtained by repeating the same operation as in Example 4 except that no crosslinking agent was used. Table 1 shows the performance of the salt-resistant water-absorbent resin. Example 6 The same operation as in Example 4 was repeated except that the amount of the water-absorbent resin (B) was changed to 49.8 g (5% by weight relative to the monomer component (A)), and the salt resistance was changed. A water-absorbing resin was obtained. Table 1 shows the performance of the salt-resistant water-absorbent resin.
【００３９】実施例７実施例１において吸水性樹脂
（Ｂ）の量を２０メッシュの金網を通過した粒子径１〜
８４０μｍの粉末とする以外は、実施例１と同様な操作
を繰り返して、耐塩性吸水性樹脂を得た。この耐塩性吸
水性樹脂の性能を表１に示す。Example 7 In Example 1, the amount of the water-absorbent resin (B) was adjusted to a particle size of 1 to 20 through a 20-mesh wire mesh.
The same operation as in Example 1 was repeated except that the powder was 840 μm, to obtain a salt-resistant water-absorbent resin. Table 1 shows the performance of the salt-resistant water-absorbent resin.
【００４０】比較例１実施例１において吸水性樹脂
（Ｂ）の量を３２５６ｇ（５０重量％対単量体成分
（Ａ））とする以外は、実施例１と同様な操作を繰り返
して、比較用樹脂を得た。この比較用樹脂の性能を表１
に示す。Comparative Example 1 The same operation as in Example 1 was repeated except that the amount of the water-absorbent resin (B) was 3256 g (50% by weight relative to the monomer component (A)). Resin was obtained. Table 1 shows the performance of this comparative resin.
Shown in
【００４１】比較例２実施例１において吸水性樹脂
（Ｂ）を用いなかった以外は、実施例１と同様な操作を
繰り返して、比較用樹脂を得た。この比較用樹脂の性能
を表１に示す。Comparative Example 2 A comparative resin was obtained by repeating the same operation as in Example 1 except that the water-absorbent resin (B) was not used. Table 1 shows the performance of the comparative resin.
【００４２】比較例３実施例１において架橋剤量を２
７．２ｇ（０．５モル％対単量体成分（Ａ））とし、か
つ吸水性樹脂（Ｂ）を用いなかった以外は、実施例１と
同様な操作を繰り返して、比較用樹脂を得た。この比較
用樹脂の性能を表１に示す。Comparative Example 3 In Example 1, the amount of the crosslinking agent was changed to 2
The same operation as in Example 1 was repeated except that the amount was 7.2 g (0.5 mol% based on the monomer component (A)) and the water-absorbing resin (B) was not used, to obtain a comparative resin. Was. Table 1 shows the performance of the comparative resin.
【００４３】比較例４減圧乾燥法にて充分に脱水を行っ
た平均分子量１０万のポリエチレンオキシド樹脂２０部
およびトリエチレンジアミン０．０５部をアセトニトリ
ル２８０部中に加え、窒素雰囲気中３０〜４０℃にて完
全に溶解せしめた後、１，４−フェニレンジイソシアナ
ート０．２部を加え７０℃にて５時間反応を行い、水に
不溶性の均一な樹脂溶液を得た。この反応生成物をガラ
スシャーレ中に流延し４０℃にて真空乾燥を行い、粉砕
することにより比較用樹脂を得た。この比較用樹脂の性
能を表１に示す。Comparative Example 4 20 parts of a polyethylene oxide resin having an average molecular weight of 100,000 and 0.05 parts of triethylenediamine, which had been sufficiently dehydrated by a vacuum drying method, were added to 280 parts of acetonitrile, and the mixture was heated to 30 to 40 ° C. in a nitrogen atmosphere. After complete dissolution, 0.2 parts of 1,4-phenylene diisocyanate was added and reacted at 70 ° C. for 5 hours to obtain a uniform resin solution insoluble in water. The reaction product was cast in a glass petri dish, vacuum dried at 40 ° C., and pulverized to obtain a comparative resin. Table 1 shows the performance of the comparative resin.
【００４４】比較例５実施例３において吸水性樹脂
（Ｂ）を用いなかった以外は、実施例３と同様な操作を
繰り返して、比較用樹脂を得た。この比較用樹脂の性能
を表１に示す。Comparative Example 5 A comparative resin was obtained by repeating the same operation as in Example 3 except that the water absorbent resin (B) was not used. Table 1 shows the performance of the comparative resin.
【００４５】比較例６攪拌機、還流冷却器、温度計、窒
素ガス導入管および滴下ロートを付した２リットルの四
つ口セパラブルフラスコにシクロヘキサン１．０リット
ルを取り、分散剤としてソルビタンモノステアレート
３．０ｇを加えて溶解させ、窒素ガスを吹き込んで溶存
酸素を追い出した。Comparative Example 6 1.0 liter of cyclohexane was placed in a 2 liter four-neck separable flask equipped with a stirrer, reflux condenser, thermometer, nitrogen gas inlet tube and dropping funnel, and sorbitan monostearate was used as a dispersant. 3.0 g was added for dissolution, and dissolved oxygen was expelled by blowing nitrogen gas.
【００４６】別にフラスコ中にアクリル酸ナトリウム８
４．６ｇ、アクリル酸２１．６ｇおよび架橋剤として
Ｎ，Ｎ´−メチレンビスアクリルアミド０．０９２５ｇ
（０．０５モル％対単量体成分（Ａ））をイオン交換水
１９７ｇに溶解し、更に実施例１で用いた吸水性樹脂
（Ｂ）１０．６ｇ（１０重量％対単量体成分（Ａ））を
加えて単量体水溶液を調整した。Separately, add sodium acrylate 8 in a flask.
4.6 g, 21.6 g of acrylic acid and 0.0925 g of N, N'-methylenebisacrylamide as a crosslinking agent
(0.05 mol% based on the monomer component (A)) was dissolved in 197 g of ion-exchanged water, and 10.6 g of the water absorbing resin (B) used in Example 1 (10 wt% based on the monomer component ( A)) was added to prepare a monomer aqueous solution.
【００４７】この単量体水溶液に過硫酸カリウム０．１
５ｇを加えて溶解させた後、窒素ガスを吹き込んで水溶
液内に溶存する酸素を追い出した。To the aqueous monomer solution was added 0.1% potassium persulfate.
After adding and dissolving 5 g, nitrogen gas was blown in to expel oxygen dissolved in the aqueous solution.
【００４８】次いで、このフラスコ内の単量体水溶液を
上記セパラブルフラスコに加えて、撹拌することにより
分散させた。その後、浴温を６５℃に昇温して重合反応
を開始させた後、２時間この温度を保持して重合を完了
した。重合終了後シクロヘキサンとの共沸脱水により含
水ゲル中の水を留去した後、濾過し、比較用樹脂を得
た。この比較用樹脂の性能を表１に示す。Next, the aqueous monomer solution in the flask was added to the separable flask and dispersed by stirring. Thereafter, the bath temperature was raised to 65 ° C. to start the polymerization reaction, and then the temperature was maintained for 2 hours to complete the polymerization. After completion of the polymerization, water in the hydrogel was distilled off by azeotropic dehydration with cyclohexane, followed by filtration to obtain a resin for comparison. Table 1 shows the performance of the comparative resin.
【００４９】[0049]
【表１】 [Table 1]
【００５０】[0050]
【発明の効果】本発明は、不飽和カルボン酸およびその
塩よりなる群から選ばれた少なくとも１種の単量体成分
（Ａ）の水溶液と、不飽和カルボン酸およびその塩より
なる群から選ばれた少なくとも１種の単量体成分を水溶
液重合することによって得られる吸水性樹脂（Ｂ）と
を、前記単量体成分（Ａ）１００重量部当たり、前記吸
水性樹脂（Ｂ）１〜３０重量部の割合で存在させて水溶
液重合することよりなる耐塩性吸水性樹脂の製造方法で
あるので、これにより得られた耐塩性が向上した耐塩性
吸水性樹脂を、例えば紙おむつや生理用品中の吸収剤に
用いた場合には、尿中の塩濃度の影響をうけにくく、安
定した吸収倍率を有し液体の吸収性に優れたものとな
り、また、海水等のシール剤に用い場合には、シール効
果が塩濃度によって影響され難くなる利点がある。The present invention provides an aqueous solution of at least one monomer component (A) selected from the group consisting of unsaturated carboxylic acids and salts thereof, and an aqueous solution of unsaturated carboxylic acids and salts thereof.
At least one monomer component selected from the group consisting of
Water-absorbent resin (B) obtained by liquid polymerization and
Of the water-absorbent resin (B) in an amount of 1 to 30 parts by weight per 100 parts by weight of the monomer component (A) to produce a salt-resistant water-absorbent resin. in a way
Therefore, when the resulting salt-resistant water-absorbent resin with improved salt resistance is used as an absorbent in disposable diapers and sanitary products, for example, it is hardly affected by the salt concentration in urine and has a stable absorption. It has a magnification and is excellent in liquid absorbability, and when it is used for a sealant such as seawater, there is an advantage that the sealing effect is hardly affected by the salt concentration.
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 昭52−51482（ＪＰ，Ａ) (58)調査した分野(Int.Cl.6，ＤＢ名) C08F 2/00 - 2/44 ────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-52-51482 (JP, A) (58) Fields investigated (Int. Cl. 6 , DB name) C08F 2/00-2/44
Claims (8)
群から選ばれた少なくとも１種の単量体成分（Ａ）の水
溶液と、 不飽和カルボン酸およびその塩よりなる群から選ばれた
少なくとも１種の単量体成分を水溶液重合することによ
って得られる吸水性樹脂（Ｂ）とを、 前記単量体成分（Ａ）１００重量部当たり、前記 吸水性
樹脂（Ｂ）１〜３０重量部の割合で存在させて水溶液重
合することよりなる耐塩性吸水性樹脂の製造方法。An aqueous solution of at least one monomer component (A) selected from the group consisting of unsaturated carboxylic acids and salts thereof, and an aqueous solution of unsaturated carboxylic acids and salts thereof.
By subjecting at least one monomer component to aqueous polymerization,
With the water-absorbent resin (B) obtained in the ratio of 1 to 30 parts by weight of the water-absorbent resin (B) per 100 parts by weight of the monomer component (A). A method for producing a salt-resistant water-absorbent resin.
項１に記載の耐塩性吸水性樹脂の製造方法。2. The method for producing a salt-resistant water-absorbent resin according to claim 1, wherein the aqueous solution polymerization is carried out with stirring and mixing.
反応容器内で撹拌混合下に行われる請求項２に記載の耐
塩性吸水性樹脂の製造方法。3. The method for producing a salt-resistant water-absorbent resin according to claim 2, wherein the aqueous solution polymerization is carried out under stirring and mixing in a reaction vessel having a plurality of rotary stirring shafts.
ーダーである請求項３に記載の耐塩性吸水性樹脂の製造
方法。4. The method for producing a salt-resistant water-absorbent resin according to claim 3, wherein the reaction vessel having a plurality of rotary stirring shafts is a kneader.
００１〜０．１モル％の量で用いる請求項１に記載の耐
塩性吸水性樹脂の製造方法。5. A cross-linking agent is added to the monomer component (A) in an amount of 0.
The method for producing a salt-resistant water-absorbing resin according to claim 1, wherein the method is used in an amount of 001 to 0.1 mol%.
１０重量％である請求項１に記載の耐塩性吸水性樹脂の
製造方法。6. The water-absorbent resin (B) has a water content of 0.1 to 6.
The method for producing a salt-resistant water-absorbent resin according to claim 1, wherein the amount is 10% by weight.
％が１〜１４９μｍの粒径を有するものである請求項１
に記載の耐塩性吸水性樹脂の製造方法。7. The water-absorbent resin (B) having a particle size of 90 to 100% by weight having a particle size of 1 to 149 μm.
3. The method for producing a salt-resistant water-absorbent resin according to item 1.
脂を乾燥し、ついで分級により該吸水性樹脂（Ｂ）の粒
度範囲に相当する吸水性樹脂（Ｃ）を除去する請求項１
に記載の耐塩性吸水性樹脂の製造方法。8. The water-absorbent resin obtained by aqueous solution polymerization is dried, and then the water-absorbent resin (C) corresponding to the particle size range of the water-absorbent resin (B) is removed by classification.
3. The method for producing a salt-resistant water-absorbent resin according to item 1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9521591A JP2901368B2 (en) | 1990-04-27 | 1991-04-25 | Method for producing salt-resistant water-absorbent resin |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2-110089 | 1990-04-27 | ||
| JP11008990 | 1990-04-27 | ||
| JP9521591A JP2901368B2 (en) | 1990-04-27 | 1991-04-25 | Method for producing salt-resistant water-absorbent resin |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH04227705A JPH04227705A (en) | 1992-08-17 |
| JP2901368B2 true JP2901368B2 (en) | 1999-06-07 |
Family
ID=26436487
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP9521591A Expired - Lifetime JP2901368B2 (en) | 1990-04-27 | 1991-04-25 | Method for producing salt-resistant water-absorbent resin |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2901368B2 (en) |
Families Citing this family (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4072833B2 (en) * | 1995-11-30 | 2008-04-09 | 住友精化株式会社 | Method for producing water absorbent resin and water absorbent resin |
| KR100819613B1 (en) * | 2003-09-19 | 2008-04-07 | 가부시키가이샤 닛폰 쇼쿠바이 | Water absorbent and producing method of same |
| AU2005210411B2 (en) | 2004-02-05 | 2008-01-31 | Nippon Shokubai Co., Ltd. | Particulate water absorbing agent and method for production thereof, and water absorbing article |
| TWI353360B (en) | 2005-04-07 | 2011-12-01 | Nippon Catalytic Chem Ind | Production process of polyacrylic acid (salt) wate |
| TWI394789B (en) | 2005-12-22 | 2013-05-01 | Nippon Catalytic Chem Ind | Water-absorbent resin composition, method of manufacturing the same, and absorbent article |
| EP1837348B9 (en) * | 2006-03-24 | 2020-01-08 | Nippon Shokubai Co.,Ltd. | Water-absorbing resin and method for manufacturing the same |
| SA08290556B1 (en) | 2007-09-07 | 2012-05-16 | نيبون شوكوباي كو. ، ليمتد | Binding Mehtod of Water Absorbent Resins |
| JP5244524B2 (en) * | 2008-09-30 | 2013-07-24 | 株式会社日本触媒 | Method for producing (meth) acrylic acid polymer |
| JP5615801B2 (en) | 2009-03-04 | 2014-10-29 | 株式会社日本触媒 | Method for producing water absorbent resin |
| JP5801203B2 (en) | 2009-09-29 | 2015-10-28 | 株式会社日本触媒 | Particulate water absorbing agent and method for producing the same |
| KR102402261B1 (en) | 2014-03-03 | 2022-05-26 | 가부시키가이샤 닛폰 쇼쿠바이 | Method for producing polyacrylic acid (salt)-based water-absorbable resin |
| KR102597740B1 (en) * | 2016-10-06 | 2023-11-07 | 메디셈 테크놀로지 에스알오 | Combined osmotic and hydrogel cervical dilators and method of making same |
| JP7231522B2 (en) | 2019-09-06 | 2023-03-01 | ユニ・チャーム株式会社 | Method for producing regenerated superabsorbent polymer, method for producing superabsorbent polymer using regenerated superabsorbent polymer, and regenerated superabsorbent polymer |
-
1991
- 1991-04-25 JP JP9521591A patent/JP2901368B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH04227705A (en) | 1992-08-17 |
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