JP3068840B2 - Method for producing water absorbent resin - Google Patents
Method for producing water absorbent resinInfo
- Publication number
- JP3068840B2 JP3068840B2 JP2223705A JP22370590A JP3068840B2 JP 3068840 B2 JP3068840 B2 JP 3068840B2 JP 2223705 A JP2223705 A JP 2223705A JP 22370590 A JP22370590 A JP 22370590A JP 3068840 B2 JP3068840 B2 JP 3068840B2
- Authority
- JP
- Japan
- Prior art keywords
- water
- parts
- weight
- absorbent resin
- carboxyl group
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Landscapes
- Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
Description
【発明の詳細な説明】 （産業上の利用分野） 本発明は吸水性樹脂の製造方法に関する。The present invention relates to a method for producing a water absorbent resin.
更に詳しくは、本発明は、紙おむつ、生理用品等の衛
生材料をはじめとして、農園芸分野や食品分野等種々の
分野に幅広い用途を持ち、残存モノマーが少なく、加圧
下での吸水倍率や吸引力等の吸水諸特性に優れ、膨潤ゲ
ルの経時安定性も良好な吸水性樹脂の製造方法に関す
る。More specifically, the present invention has a wide range of uses in various fields such as the agricultural and horticultural fields and the food field, including sanitary materials such as disposable diapers and sanitary products, has a low residual monomer, and has a water absorption capacity and a suction force under pressure. The present invention relates to a method for producing a water-absorbent resin which is excellent in various water-absorbing properties, such as water-absorbing resin, and has good stability over time of a swollen gel.
（従来の技術） 吸水性樹脂は、近年、その特性を生かしオムツ、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。(Prior Art) In recent years, water-absorbing resins have been utilized in various water-absorbing materials such as diapers, sanitary products, soil water retention agents, sealants, etc., taking advantage of their properties.
この様な吸水性樹脂としては、カルボキシメチルセル
ロース架橋物、（特開昭56−15,458号公報）、架橋ポリ
ビニルアルコール変性物（特開昭54−20,093号公報）、
架橋イソブチレン−無水マレイン酸共重合体（特開昭56
−36,504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53−13,495号公報）、ポリエ
チレンオキシド部分架橋物（特開昭61−130,324号公
報）、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
のグラフト共重合物（特公昭53−46,199号公報）、アク
リル酸もしくはメタクリル酸塩重合体の架橋物（特開昭
55−84,304号公報、特開昭55−19,243号公報）等が知ら
れている。しかし、これらの製法により得られた吸水性
樹脂は、例えば吸収倍率が低かったり、たとえ吸収倍率
が高くても吸引力や加圧下の吸収倍率が劣る等の欠点を
有しており、また樹脂中の残存モノマー含有量も多いも
のであった。Examples of such a water-absorbent resin include carboxymethylcellulose cross-linked products (JP-A-56-15458), cross-linked polyvinyl alcohol-modified products (JP-A-54-20093),
Crosslinked isobutylene-maleic anhydride copolymer (JP-A-56
JP-A-36,504), saponified acrylate-vinyl acetate copolymer (JP-B-53-13,495), partially cross-linked polyethylene oxide (JP-A-61-130,324), starch-acrylonitrile graft copolymer A hydrolyzate of the union (JP-B-49-43,395), a starch-acrylic acid graft copolymer (JP-B-53-46,199), and a crosslinked product of acrylic acid or methacrylate polymer (JP-A No.
Japanese Patent Application Laid-Open No. 55-84,304 and Japanese Patent Application Laid-Open No. 55-19,243) are known. However, the water-absorbent resins obtained by these production methods have drawbacks such as low absorption capacity, and inferior suction power or absorption capacity under pressure even if the absorption capacity is high. Was also high in residual monomer content.
（発明が解決しようとする課題） 吸水性樹脂の吸収倍率、吸引力、加圧下の吸収倍率等
の吸水諸特性をバランス良く改良する方法として、吸水
性樹脂の表面を親水性架橋剤で架橋させる方法が知られ
ている（特開昭58−180,233号公報、特開昭59−189,103
号公報、特開昭61−16,903号公報、特開昭57−44,627号
公報、特開昭58−117,222号公報等）。(Problems to be Solved by the Invention) As a method for improving various well-absorbing properties of a water-absorbent resin such as absorption capacity, suction power, and absorption capacity under pressure, the surface of the water-absorbent resin is crosslinked with a hydrophilic crosslinking agent. Methods are known (JP-A-58-180,233, JP-A-59-189,103).
JP-A-61-16,903, JP-A-57-44,627, JP-A-58-117,222, etc.).
これらの技術により吸引力、加圧下の吸収倍率等は向
上させることができるが、吸水性樹脂の残存モノマー
は、何ら低減されず、むしろ、架橋反応を行なうことに
より残存モノマーが増加する場合も認められた。These techniques can improve the suction power, the absorption capacity under pressure, etc., but the residual monomer of the water-absorbent resin is not reduced at all, but rather, the case where the residual monomer increases by performing a crosslinking reaction is also recognized. Was done.
また、吸水性樹脂の残存モノマーを減らす技術として
報告されている方法は、水溶性重合体に関し古くから行
なわれている技術と同じくほぼ次の３つに大別される。In addition, the methods reported as a technique for reducing the residual monomer of the water-absorbent resin are roughly classified into the following three, similar to the techniques that have been used for water-soluble polymers for a long time.
（１）重合開始剤を増量あるいは分割添加する方法（特
開昭56−72,005号公報） （２）溶媒等による抽出法（特開平１−292,003号公
報） （３）二重結合に付加させることのできる還元性物質等
により、残存モノマーを他の誘導体に導く方法（特開平
１−62,317号公報、***特許公開第3724709号公報等） これらの残存モノマー低減の方法のうち前記（１）の
方法では、重合体の分子量の低下や過度の自己架橋反応
に伴なう吸収倍率の低下、水可溶性成分の増加等が認め
られ、残存モノマーは低減されるものの吸水性樹脂の特
性が低下する。(1) A method of increasing or dividing and adding a polymerization initiator (JP-A-56-72,005) (2) Extraction with a solvent or the like (JP-A-1-292,003) (3) Addition to a double bond Method for leading the remaining monomer to another derivative by using a reducing substance or the like (Japanese Patent Laid-Open No. 1-62,317, Japanese Patent Publication No. 3724709, etc.) Among these methods for reducing the remaining monomer, the method (1) above In this case, a decrease in the molecular weight of the polymer, a decrease in absorption capacity accompanying an excessive self-crosslinking reaction, an increase in water-soluble components, and the like are observed, and although the remaining monomers are reduced, the properties of the water-absorbent resin are reduced.
前記（２）の方法も、大量の溶剤を必要とし、その回
収コストが非常に高く、好ましい方法とはいい難い。The method (2) also requires a large amount of solvent, the recovery cost is very high, and is not a preferable method.
また、前記（３）の方法のなかで特開平１−62,317号
公報に記載された方法では、本発明者らの行なった結果
によれば残存モノマーの低減率はまだまだ低く、また西
独特許公開第3724709号公報の方法においても、残存モ
ノマーは低減されるものの、用いる付加物質の種類、量
によっては得られた吸水性樹脂の膨潤ゲルが経時安定性
に欠ける場合も認められた。その上、この***特許公開
第3724709号公報に記載の方法を、前述したような表面
部分を親水性架橋剤で処理したバランスのよい吸水諸特
性を有する吸水性樹脂に応用した場合、その樹脂が本来
有していた吸収倍率、加圧下の吸収倍率、吸引力等の吸
水諸特性を著しく低下させることが明らかになった。こ
れは、該方法では吸水性樹脂粉末100重量部に対して50
〜500重量部という多量の水を用いる為に、その表面部
分の高架橋層が混合時水による膨潤のために劣化、破壊
されるためと考えられる。また、この場合、後に乾燥工
程が必要となりプロセス的にも高価なものとなってしま
う。In the method of (3) described in JP-A-1-62,317, the reduction rate of the residual monomer is still low according to the results of the present inventors, and the method disclosed in West German Patent Publication No. In the method of Japanese Patent No. 3724709, although the residual monomer was reduced, it was also recognized that the obtained water-absorbent resin swelled gel lacked the stability over time depending on the type and amount of the additional substance used. In addition, when the method described in West German Patent Publication No. 3724709 is applied to a water-absorbing resin having well-balanced water-absorbing properties obtained by treating the surface portion with a hydrophilic cross-linking agent as described above, the resin becomes It was revealed that various properties of water absorption, such as absorption capacity, absorption capacity under pressure, and suction force, which were originally possessed, were significantly reduced. This is because, in the method, 50 parts by weight of the water-absorbent resin powder is used.
It is considered that since a large amount of water of up to 500 parts by weight is used, the highly crosslinked layer on the surface thereof is deteriorated and destroyed due to swelling due to water during mixing. Further, in this case, a drying step is required later, and the process becomes expensive.
また、逆に前記（３）の方法で得られた残存モノマー
の低減された吸水性樹脂の表面を前述した公知技術に基
づき親水性架橋剤で架橋した場合、製造プロセスが長く
なる上に一旦低減された残存モノマーが架橋反応中に増
加したり、得られた樹脂の膨潤ゲルが経時安定性に欠け
る状態になる場合も認められた。Conversely, when the surface of the water-absorbent resin obtained by the above method (3) with reduced residual monomers is cross-linked with a hydrophilic cross-linking agent based on the above-mentioned known technology, the production process becomes longer and once reduced. In some cases, the amount of the residual monomer increased during the cross-linking reaction, or the swollen gel of the obtained resin was in a state lacking in stability over time.
（課題を解決するための手段） 本発明者らは上記実状に鑑み、鋭意研究を重ねた結
果、カルボキシル基を有する吸水性樹脂粉末に特定量の
水にカルボキシル基と反応し得る官能基を２個以上有す
る架橋剤と還元性物質とを溶解させて得られる水性液を
混合し、加熱反応させるという工業的にも簡単な方法を
行うことにより前述したような問題がことごとく解決
し、残存モノマーが効率よく低減され、かつ吸水諸特性
にも著しく優れ膨潤ゲルの経時安定性も良好な吸水性樹
脂が得られることを見い出し、本発明を完成するに至っ
た。(Means for Solving the Problems) In view of the above-mentioned circumstances, the present inventors have conducted intensive studies and as a result, have found that a water-absorbent resin powder having a carboxyl group has two functional groups capable of reacting with the carboxyl group in a specific amount of water. By mixing an aqueous liquid obtained by dissolving a cross-linking agent having at least one reducing agent and a reducing substance, and performing an industrially simple method of performing a heating reaction, the above-described problem is completely solved, and the residual monomer is eliminated. The present inventors have found that a water-absorbent resin which is efficiently reduced, has excellent water-absorbing properties, and has excellent stability over time of the swollen gel can be obtained, thereby completing the present invention.
本発明は、カルボキシル基を有する吸水性樹脂粉末
（１）100重量部に、カルボキシル基と反応し得る官能
基を２個以上有する架橋剤（２）および還元性物質
（３）を溶解させた５〜50重量部の水を含有する水性液
を混合し、加熱することを特徴とする吸水性樹脂（５）
の製造方法に関する。According to the present invention, a crosslinking agent (2) having at least two functional groups capable of reacting with a carboxyl group and a reducing substance (3) are dissolved in 100 parts by weight of a water-absorbing resin powder having a carboxyl group (1). A water-absorbent resin characterized by mixing and heating an aqueous liquid containing up to 50 parts by weight of water (5)
And a method for producing the same.
また、本発明は、カルボキシル基を有する吸水性樹脂
粉末（１）100重量部に、カルボキシル基と反応し得る
官能基を２個以上有する架橋剤（２）0.01〜10重量、還
元性物質（３）および水５〜50重量部を混合し、60〜25
0℃で加熱架橋することを特徴とする吸水性樹脂（５）
の製造方法に関する。In addition, the present invention relates to a cross-linking agent having two or more functional groups capable of reacting with a carboxyl group per 100 parts by weight of a water-absorbent resin powder having a carboxyl group (1), 0.01 to 10 wt. ) And 5 to 50 parts by weight of water,
Water-absorbent resin characterized by being crosslinked by heating at 0 ° C. (5)
And a method for producing the same.
本発明において使用できる吸水性樹脂粉末（１）は、
水中において多量の水を吸収して膨潤しヒドロゲルを形
成する従来公知の樹脂であり、カルボキシル基を有して
いることが必要である。例えば、デンプン−アクリロニ
トリルグラフト共重合体の加水分解物、デンプン−アク
リル酸グラフト重合体の（部分）中和物、アクリル酸エ
ステル−酢酸ビニル共重合体のケン化物、アクリロニト
リル共重合体もしくはアクリルアミド共重合体の加水分
解物またはこれらの架橋体、カルボキシル基含有架橋ポ
リビニルアルコール変性物、自己架橋型ポリアクリル酸
（部分）中和物、ポリアクリル酸部分中和物の架橋体、
架橋イソブチレン−無水マレイン酸共重合体（部分）の
中和物等を挙げることができる。The water-absorbent resin powder (1) that can be used in the present invention includes:
It is a conventionally known resin that absorbs a large amount of water in water and swells to form a hydrogel, and needs to have a carboxyl group. For example, a hydrolyzate of a starch-acrylonitrile graft copolymer, a (partially) neutralized product of a starch-acrylic acid graft polymer, a saponified product of an acrylate-vinyl acetate copolymer, an acrylonitrile copolymer or an acrylamide copolymer A hydrolyzate of the union or a crosslinked product thereof, a carboxyl group-containing crosslinked polyvinyl alcohol modified product, a self-crosslinked polyacrylic acid (partially) neutralized product, a crosslinked product of a partially neutralized polyacrylic acid,
Examples include a neutralized product of a crosslinked isobutylene-maleic anhydride copolymer (part).
最終的に得られる樹脂の吸水諸特性を考えると、アク
リル酸（塩）を主成分とする水溶性エチレン性不飽和単
量体の架橋重合体が好ましい。吸水性樹脂粉末（１）を
有するカルボキシル基の量については特に制限はない
が、通常、吸水性樹脂粉末（１）100gにつきカルボキシ
ル基が0.01当量以上存在することが好ましい。Considering the various properties of water absorption of the finally obtained resin, a crosslinked polymer of a water-soluble ethylenically unsaturated monomer containing acrylic acid (salt) as a main component is preferable. The amount of the carboxyl group having the water-absorbent resin powder (1) is not particularly limited, but usually, it is preferable that the carboxyl group is present in an amount of 0.01 equivalent or more per 100 g of the water-absorbent resin powder (1).
吸水性樹脂粉末（１）を得るための重合方法として
は、水溶液重合、逆相懸濁重合等が例示できるが、特に
制限されない。Examples of the polymerization method for obtaining the water-absorbent resin powder (1) include aqueous solution polymerization and reversed-phase suspension polymerization, but are not particularly limited.
これらの吸水性樹脂粉末（１）中の含水率は、通常、
30％以下、さらには15％以下のものが本発明に好適に使
用できる。The water content in these water absorbent resin powders (1) is usually
Those having 30% or less, more preferably 15% or less can be suitably used in the present invention.
本発明ではこのようにして得られたカルボキシル基を
有する吸水性樹脂粉末（１）（通常100〜3000ppmの残存
モノマーを含有している場合が多い）、カルボキシル基
と反応し得る官能基を２個以上有する架橋剤（２）と還
元性物質（３）を溶解させた特定量の水を含有する水性
液を混合し、加熱処理することで、吸水諸特性に優れ、
膨潤ゲルの経時安定性も高く、かつ残存モノマー含有量
の著しく低減された樹脂（５）を得ることができる。In the present invention, the thus obtained water-absorbent resin powder having a carboxyl group (1) (which usually contains 100 to 3000 ppm of a residual monomer in many cases) has two functional groups capable of reacting with the carboxyl group. By mixing an aqueous liquid containing a specific amount of water in which the crosslinking agent (2) having the above and the reducing substance (3) are dissolved, and subjecting the mixture to heat treatment, excellent water absorption properties are obtained.
The resin (5) having high stability over time of the swollen gel and having a significantly reduced residual monomer content can be obtained.
本発明で用いることのできるカルボキシル基と反応し
得る官能基を２個以上有する架橋剤（２）としては特に
制限はないが、例えば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、テトラエチレン
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、1,4−ブタンジ
オール、1,5−ペンタンジオール、1,6−ヘキサンジオー
ル、トリメチロールプロパン、ジエタノールアミン、ト
リエタノールアミン、ポリオキシプロピレン、オキシエ
チレンオキシプロピレンブロック共重合体、ポリビニル
アルコール、ペンタエリスリトール、ソルビトール等の
多価アルコール化合物；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、グリセロールポリグリシジルエーテル、ジグリセ
ロールポリグリシジルエーテル、ポリグリセロールポリ
グリシジルエーテル、ソルビトールポリグリシジルエー
テル、ペンタエリスリトールポリグリシジルエーテル、
プロピレングリコールジグリシジルエーテル、ポリプロ
ピレングリコールジグリシジルエーテル等の多価グリシ
ジル化合物;2,2−ビスヒドロキシメチルブタノール−ト
リス［３−（１−アジリジニル）プロピオネート］、1,
6−ヘキサメチレンジエチレンウレア、ジフェニルメタ
ン−ビス−4,4′−,N,N′−ジエチレンウレア等の多価
アジリジン化合物；エピクロルヒドリン、α−メチルク
ロルヒドリン等ハロエポキシ化合物；エチレンジアミ
ン、ジエチレントリアミン、トリエチレンテトラミン、
テトラエチレンペンタミン、ペンタエチレンヘキサミ
ン、ポリエチレンイミン等の多価アミン化合物;2,4−ト
ルイレンジイソシアネート、ヘキサメチレンジイソシア
ネート等の多価イソシアネート化合物等を例示すること
ができる。特に好ましくは多価アルコール化合物、多価
グリシジル化合物であり、最も好ましくは多価アルコー
ル化合物である。これらの中でも分子量が100以上の化
合物が本発明において吸水諸特性に優れた吸水性樹脂
（５）を与える点で好ましい。The crosslinking agent (2) having two or more functional groups capable of reacting with a carboxyl group that can be used in the present invention is not particularly limited, and examples thereof include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, Glycerin, polyglycerin, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, trimethylolpropane, diethanolamine, triethanolamine, polyoxypropylene, oxyethyleneoxypropylene block copolymer Polyhydric alcohol compounds such as coalesce, polyvinyl alcohol, pentaerythritol and sorbitol; ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerol poly Glycidyl ether, diglycerol polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitol polyglycidyl ether, pentaerythritol polyglycidyl ether,
Polyvalent glycidyl compounds such as propylene glycol diglycidyl ether and polypropylene glycol diglycidyl ether; 2,2-bishydroxymethylbutanol-tris [3- (1-aziridinyl) propionate], 1,
Polyvalent aziridine compounds such as 6-hexamethylene diethylene urea and diphenylmethane-bis-4,4 '-, N, N'-diethylene urea; haloepoxy compounds such as epichlorohydrin and α-methylchlorohydrin; ethylenediamine, diethylenetriamine, triethylenetetramine ,
Examples thereof include polyvalent amine compounds such as tetraethylenepentamine, pentaethylenehexamine and polyethyleneimine; and polyvalent isocyanate compounds such as 2,4-toluylene diisocyanate and hexamethylene diisocyanate. Particularly preferred are polyhydric alcohol compounds and polyglycidyl compounds, and most preferred are polyhydric alcohol compounds. Among these, compounds having a molecular weight of 100 or more are preferred in the present invention in that the water-absorbent resin (5) having excellent water-absorbing properties is provided.
これら架橋剤（２）の使用量は、その種類にもよる
が、一般に、吸水性樹脂粉末（１）100重量部に対して
0.01〜10重量部、好ましくは0.5〜５重量部が適当であ
る。この量が0.01重量部未満の場合には表面の架橋効果
があらわれず、また10重量部を越えて使用すると吸水倍
率が極端に低下することがある。The amount of the cross-linking agent (2) used depends on the type thereof, but is generally based on 100 parts by weight of the water-absorbent resin powder (1).
A suitable amount is 0.01 to 10 parts by weight, preferably 0.5 to 5 parts by weight. When the amount is less than 0.01 part by weight, the surface crosslinking effect is not exhibited, and when it exceeds 10 parts by weight, the water absorption capacity may be extremely reduced.
本発明で用いることのできる還元性物質（３）として
は、亜硫酸（塩）、亜硫酸水素塩、亜リン酸（塩）、次
亜リン酸（塩）、チオ硫酸（塩）、アンモニア、アミン
類、アミノ酸類等をあげることができる。The reducing substance (3) that can be used in the present invention includes sulfurous acid (salt), bisulfite, phosphorous acid (salt), hypophosphorous acid (salt), thiosulfuric acid (salt), ammonia, amines , Amino acids and the like.
具体例としては、亜硫酸ナトリウム、亜硫酸カリウ
ム、亜硫酸カルシウム、亜硫酸アンモニウム、亜硫酸、
亜硫酸水素カリウム、亜硫酸水素ナトリウム、亜硫酸水
素アンモニウム、チオ硫酸ナトリウム、チオ硫酸アンモ
ニウム、チオ硫酸カリウム、チオ硫酸マグネシウム、次
亜リン酸ナトリウム、次亜リン酸カリウム、次亜リン酸
アンモニウム、亜リン酸ナトリウム、亜リン酸カリウ
ム、亜リン酸アンモニウム、アンモニア、塩化アンモニ
ウム、メチルアミン、エチレンアミン、ブチルアミン、
ジメチルアミン、ジエチルアミン、シクロヘキシルアミ
ン、ベンジルアミン、モルフォリン、グリシン、アラニ
ン、バリン、ロイシン、セリン、スレオニン、システイ
ン、シスチン、チロシン、アスパラギン酸、グルタミン
酸、リジン、アルギニン等を用いることができ、これら
のうち前述した使用する架橋剤（２）との反応性を考慮
して１種又は２種以上を使用することができる。Specific examples include sodium sulfite, potassium sulfite, calcium sulfite, ammonium sulfite, sulfurous acid,
Potassium bisulfite, sodium bisulfite, ammonium bisulfite, sodium thiosulfate, ammonium thiosulfate, potassium thiosulfate, magnesium thiosulfate, sodium hypophosphite, potassium hypophosphite, ammonium hypophosphite, sodium phosphite, Potassium phosphite, ammonium phosphite, ammonia, ammonium chloride, methylamine, ethyleneamine, butylamine,
Dimethylamine, diethylamine, cyclohexylamine, benzylamine, morpholine, glycine, alanine, valine, leucine, serine, threonine, cysteine, cystine, tyrosine, aspartic acid, glutamic acid, lysine, arginine and the like can be used. One or more kinds can be used in consideration of the reactivity with the crosslinking agent (2) used above.
これらのうち残存モノマーの低減率から考えると、好
ましくは亜硫酸（塩）亜硫酸水素塩アンモニア、アミノ
酸塩であり、表面部分の架橋反応の促進をも伴うために
最も好ましいのは亜硫酸（塩）、亜硫酸水素塩である。Among these, from the viewpoint of the reduction rate of the residual monomer, sulfite (salt) bisulfite ammonia and amino acid salt are preferred, and sulfite (salt) and sulfite are most preferred because they also promote the cross-linking reaction of the surface portion. It is a hydrogen salt.
本発明では還元性物質（３）に併用して架橋剤（２）
を使用するため、架橋剤（２）を使用しない場合に比べ
ゲルの安定性は各段に向上する。還元性物質（３）の使
用量は、吸水性樹脂粉末（１）に残存している残存モノ
マー量によるが、一般に、吸水性樹脂（１）100重量部
に対して0.001〜５重量部、好ましくは0.005〜0.5重量
部、最も好ましくは0.01〜0.1重量部である。還元性物
質（３）の量が５重量部をこえると、ゲルの安定性をは
じめ吸水性樹脂粉末（１）の諸特性が低下したり、還元
性物質（３）が樹脂中に残存する場合がある。一方、0.
001重量部以下だと、残存モノマーの低減効果が認めら
れにくくなる場合がある。In the present invention, the crosslinking agent (2) is used in combination with the reducing substance (3).
, The stability of the gel is improved in each step as compared with the case where the crosslinking agent (2) is not used. The amount of the reducing substance (3) to be used depends on the amount of residual monomers remaining in the water-absorbent resin powder (1), but is generally 0.001 to 5 parts by weight, preferably 100 parts by weight of the water-absorbent resin (1). Is from 0.005 to 0.5 part by weight, most preferably from 0.01 to 0.1 part by weight. When the amount of the reducing substance (3) exceeds 5 parts by weight, various properties of the water-absorbent resin powder (1) including the stability of the gel are reduced, or the reducing substance (3) remains in the resin. There is. On the other hand, 0.
If the amount is less than 001 parts by weight, the effect of reducing the residual monomer may be hardly recognized.
本発明において、架橋剤（２）と還元性物質（３）を
同時に溶解させ、吸水性樹脂粉末（１）に混合される水
性液中に含まれる水の量は、吸水性樹脂粉末（１）100
重量部に対し５〜50重量部、好ましくは７〜30重量部で
ある。水の量が50重量部を越えると加熱処理後の吸水性
樹脂の吸収倍率や加圧下の吸収倍率が非常に低下し、ま
た、加熱処理条件によっては、得られた樹脂の膨潤ゲル
が経時安定性に欠けたものとなる場合がある。一方、５
重量部未満では残存モノマーの低減率が低くなる。In the present invention, the amount of water contained in the aqueous liquid mixed with the water-absorbent resin powder (1) by simultaneously dissolving the cross-linking agent (2) and the reducing substance (3) is as follows. 100
It is 5 to 50 parts by weight, preferably 7 to 30 parts by weight based on parts by weight. When the amount of water exceeds 50 parts by weight, the absorption capacity of the water-absorbent resin after heat treatment and the absorption capacity under pressure are significantly reduced, and depending on the heat treatment conditions, the swelling gel of the obtained resin is stable over time. It may be lacking in gender. 5
If the amount is less than parts by weight, the reduction ratio of the residual monomer is low.
さらに、水性液中に水と混和可能な親水性有機溶剤を
含有させると、優れた吸水諸特性を有し、残存モノマー
が効率よく低減された吸水性樹脂が得られ、より一層好
ましい。Further, when a water-miscible hydrophilic organic solvent is contained in the aqueous liquid, a water-absorbing resin having excellent water-absorbing properties and having efficiently reduced residual monomers can be obtained, which is even more preferable.
この場合の親水性有機溶剤としては、メタノール、エ
タノール、イソプロパノール、ブタノール、エチレング
リコールモノメチルエーテル、エチレングリコールモノ
エチルエーテル、プロピレングリコールモノメチルエー
テル、テトラヒドロフラン、ジメチルホルムアミド、ジ
メチルスルホキシド、アセトン、メチルエチレンケトン
等を挙げることができ、中でもエタノール、イソプロパ
ノールが好ましい。Examples of the hydrophilic organic solvent in this case include methanol, ethanol, isopropanol, butanol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, tetrahydrofuran, dimethylformamide, dimethyl sulfoxide, acetone, and methyl ethylene ketone. Among them, ethanol and isopropanol are preferred.
親水性有機溶剤を用いる場合の使用量は使用する水の
量や還元性物質の溶解度にもよるが、通常、吸水性樹脂
粉末（１）100重量部に対し0.1〜50重量部、好ましくは
0.5〜８重量部である。0.1重量部以下では有機溶剤を用
いた効果が現われ難く、50重量部を越すと経済的に不利
となるばかりでなく残存モノマーが効率よく低減されな
い。The amount used when the hydrophilic organic solvent is used depends on the amount of water used and the solubility of the reducing substance, but is usually 0.1 to 50 parts by weight, preferably 100 to 100 parts by weight of the water-absorbent resin powder (1).
0.5 to 8 parts by weight. If the amount is less than 0.1 part by weight, the effect of using the organic solvent is unlikely to appear. If the amount exceeds 50 parts by weight, not only is it economically disadvantageous, but also the residual monomer is not efficiently reduced.
また、水性液中の親水性有機溶剤の量が40重量％を越
えると、残存モノマーの低減率が低くなるため好ましく
ない。好ましくは20重量％以下、最も好ましくは10〜20
重量％である。On the other hand, if the amount of the hydrophilic organic solvent in the aqueous liquid exceeds 40% by weight, the rate of reduction of the residual monomer is undesirably low. Preferably not more than 20% by weight, most preferably 10-20
% By weight.
本発明における製造方法の実施態様を表わす具体例と
しては、通常、次の方法を挙げることができる。As a specific example showing an embodiment of the production method in the present invention, the following method can be usually mentioned.
（１）吸水性樹脂粉末（１）に架橋剤（２）および還元
性物質（３）を溶解した水溶液を添加し、均一に混合
し、加熱処理する方法。(1) A method in which an aqueous solution in which a crosslinking agent (2) and a reducing substance (3) are dissolved is added to the water-absorbent resin powder (1), mixed uniformly, and heat-treated.
（２）吸水性樹脂粉末（１）に架橋剤（２）および還元
性物質（３）を溶解した水溶液にさらに還元性物質
（３）の溶解性を妨げない範囲で親水性有機溶剤を加え
た水性液を添加し、均一に混合して加熱処理する方法。(2) A hydrophilic organic solvent is further added to an aqueous solution in which the crosslinking agent (2) and the reducing substance (3) are dissolved in the water-absorbing resin powder (1) as long as the solubility of the reducing substance (3) is not hindered. A method in which an aqueous liquid is added, mixed uniformly, and heat-treated.
（３）吸水性樹脂粉末（１）を界面活性剤もしくは分散
安定剤を含有する疎水性有機溶剤に分散させ、攪拌下、
架橋剤（２）および還元性物質（３）を溶解した水溶液
を添加し、系内を加熱処理する方法。(3) The water-absorbent resin powder (1) is dispersed in a hydrophobic organic solvent containing a surfactant or a dispersion stabilizer, and
A method in which an aqueous solution in which a crosslinking agent (2) and a reducing substance (3) are dissolved is added, and the inside of the system is heat-treated.
（４）吸水性樹脂粉末（１）に架橋剤（２）および還元
性物質（３）を溶解した水溶液を添加し、均一に混合し
た後、さらに攪拌下、高湿状態下に保ち、水分を与えた
のち加熱処理する方法。(4) An aqueous solution in which a crosslinking agent (2) and a reducing substance (3) are dissolved is added to the water-absorbent resin powder (1), and the mixture is mixed uniformly. Heat treatment after giving.
これらの添加混合に用いる混合機としては、通常の攪
拌機、混合機、捏和機を用いることができる。例えば円
筒型混合機、二重円錘型混合機、流動化型混合機、Ｖ型
混合機、リボン型混合機、スクリュー型混合機、回転円
盤型混合機、気流型混合機、双腕型捏和機、インターナ
ルミキサー、マラー型捏和機、ロールミキサー、スクリ
ュー型押出機等が挙げられるが、樹脂の表面を均一に著
しく改質し残存モノマーを低減させる効果をさらに高
め、高い生産性を得るためにも高速回転パトルを有し、
機械的混合力の大きな混合機がより好ましい。また、吸
水性樹脂粉末（１）粉体を流下させ、そこに水性液の液
滴を噴霧し、並流状態で両者を接触させ、機械的混合力
なしに混合する方法も本発明に使用できる。また、樹脂
表面の均一改質と残存モノマー低減を最も効率よく行う
ために混合後加熱処理に至まで、低温、好ましくは20−
40℃で、一定時間放置しておくことが好ましい。この放
置時間は、通常、１〜60分、好ましくは３〜30分程度で
ある。As a mixer used for the addition and mixing, an ordinary stirrer, mixer and kneader can be used. For example, cylindrical mixer, double conical mixer, fluidized mixer, V-type mixer, ribbon-type mixer, screw-type mixer, rotating disk-type mixer, air-flow-type mixer, double-arm kneader Examples include a Japanese machine, an internal mixer, a muller-type kneader, a roll mixer, and a screw-type extruder, which further enhance the effect of uniformly and significantly modifying the surface of the resin to reduce residual monomers, thereby increasing productivity. Also has a high-speed rotating pattle to obtain,
A mixer having a large mechanical mixing force is more preferable. Further, a method in which a water-absorbent resin powder (1) powder is allowed to flow down, droplets of an aqueous liquid are sprayed thereon, and the two liquids are brought into contact in a co-current state to mix them without mechanical mixing force can also be used in the present invention. . In addition, in order to perform the most uniform reforming of the resin surface and the reduction of residual monomers, up to a heating treatment after mixing, at a low temperature, preferably 20-
It is preferable to leave at 40 ° C. for a certain period of time. This standing time is usually about 1 to 60 minutes, preferably about 3 to 30 minutes.
また、混合後架橋反応を行なわせるための加熱処理に
は通常の乾燥機や加熱炉を用いることができる。例え
ば、溝型攪拌乾燥器、回転乾燥器、円盤乾燥器、捏和乾
燥器、流動層乾燥器、気流乾燥器、赤外線乾燥器等であ
る。その場合加熱処理温度は60〜250℃、好ましくは90
〜230℃である。250℃より温度が高いと、吸収倍率が低
下しすぎたり、残存モノマーの低減が効率よくなされな
い場合があり好ましくない。一方、60℃以下では、架橋
反応が円滑に行なわれにくくなる。Further, for the heat treatment for causing a crosslinking reaction after mixing, a usual dryer or heating furnace can be used. For example, a channel-type stirring dryer, a rotary dryer, a disk dryer, a kneading dryer, a fluidized-bed dryer, a flash dryer, an infrared dryer, and the like. In that case, the heat treatment temperature is 60 to 250 ° C, preferably 90 ° C.
~ 230 ° C. If the temperature is higher than 250 ° C., the absorption capacity may be too low or the residual monomer may not be efficiently reduced, which is not preferable. On the other hand, when the temperature is lower than 60 ° C., the crosslinking reaction is difficult to be carried out smoothly.
さらに、これら架橋剤（２）還元性物質（３）を溶解さ
せた水性液の添加時に、水性液中にさらに消臭剤、香
料、薬剤、肥料、染料、含量、短繊維等を介在させて得
られる吸水性樹脂に新たな機能を付与することもでき
る。Further, at the time of addition of the aqueous liquid in which the crosslinking agent (2) and the reducing substance (3) are dissolved, a deodorant, a fragrance, a drug, a fertilizer, a dye, a content, a short fiber, and the like are further interposed in the aqueous liquid. New functions can be imparted to the resulting water-absorbent resin.
（実施例） 以下、実施例により本発明をさらに詳細に説明するが
本発明はこれによつて限定されるものではない。(Examples) Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited thereto.
吸水性樹脂の諸物性と諸性能は以下のようにして求め
た。Various physical properties and various properties of the water-absorbing resin were determined as follows.
（Ａ）残存モノマー 200mlのビーカーに脱イオン水100mlを加え、そこに吸
水性樹脂1.0gを撹拌下加えて脱イオン水を全量ゲル化さ
せた。１時間後リン酸水溶液5mlを添加することによ
り、ゲルを収縮させ、撹拌後吸水性樹脂分散液を瀘紙を
用いて瀘過し、瀘過液を高速液体クロマトグラフィーで
分析した。(A) 100 ml of deionized water was added to a beaker of 200 ml of residual monomer, and 1.0 g of a water-absorbent resin was added thereto with stirring to gel the whole amount of deionized water. One hour later, the gel was shrunk by adding 5 ml of an aqueous phosphoric acid solution. After stirring, the water-absorbent resin dispersion was filtered using a filter paper, and the filtrate was analyzed by high performance liquid chromatography.
一方、既知の濃度を示すモノマー標準液を同様に分析
して得た検量線を外部標準となし、瀘過液の希釈倍率を
考慮して、吸水性樹脂中の残存モノマー量を求めた。On the other hand, a calibration curve obtained by similarly analyzing a monomer standard solution having a known concentration was used as an external standard, and the amount of residual monomer in the water-absorbent resin was determined in consideration of the dilution ratio of the filtrate.
（Ｂ）吸収倍率 吸収性樹脂0.2gを不織布製のティーバック式袋（40mm
×150mm）に均一に入れ、0.9重量％塩化ナトリウム水溶
液に浸漬し、30分後にこのティーバック式袋を引き上
げ、一定時間水切りをした後、その重量を測定し、以下
の式で吸水倍率を算出した。(B) Absorption ratio 0.2 g of absorbent resin in a non-woven tea bag bag (40 mm
× 150mm), immersed in 0.9% by weight aqueous sodium chloride solution, 30 minutes later, lifted up this tea bag type bag, drained it for a certain period of time, measured its weight, and calculated the water absorption capacity by the following formula did.
（Ｃ）加圧下吸収倍率 第１図は、吸水樹脂の加圧下吸収倍率の測定装置の説
明用断面図である。第１図に示す装置を用いて加圧下の
吸収倍率を測定する。ビュレット１の上口２に栓３を
し、測定台４と空気口５を等高位にセットする。測定台
４中の直径70mmのガラスフィルター（NO.1）６上に濾紙
７、吸水性樹脂９（0.2g）および濾紙７′を載せ、さら
に20g/cm2のおもり８を載せ、その後30分にわたって吸
収した人工尿（組成：尿素1.9％、NaCl0.8％、CaCl20.1
％、MgSO40.1％を含有する脱イオン水）の値を加圧下の
吸収倍率（ml/g）として表わした。 (C) Absorbency under load FIG. 1 is a cross-sectional view for explaining an apparatus for measuring the absorbency under pressure of a water-absorbent resin. The absorption capacity under pressure is measured using the apparatus shown in FIG. The upper port 2 of the burette 1 is plugged, and the measuring table 4 and the air port 5 are set at the same height. A filter paper 7, a water-absorbent resin 9 (0.2 g) and a filter paper 7 'are placed on a glass filter (NO.1) 6 having a diameter of 70 mm in a measuring table 4, and a weight 8 of 20 g / cm 2 is further placed thereon. Artificial urine (composition: urea 1.9%, NaCl 0.8%, CaCl 2 0.1
%, Deionized water containing 0.1% MgSO 4 ) were expressed as absorption capacity under pressure (ml / g).
（Ｃ）吸引力 ティッシュペーパー（55mm×75mm、16枚重ね）の上に
人工尿20mlをシリンジで注ぎ人工尿を含んだ基材を作成
し、その基材の上に、吸水性樹脂1.0gを置いた。10分後
に膨潤ゲルを採取して、その重量を測定することによ
り、ティッシュペーパーからの液の吸引力とした。(C) Suction force 20 ml of artificial urine is poured on a tissue paper (55 mm x 75 mm, 16 layers) with a syringe to create a base material containing artificial urine, and 1.0 g of water-absorbent resin is placed on the base material. placed. After 10 minutes, the swollen gel was collected, and its weight was measured to determine the suction force of the liquid from the tissue paper.
また同時に、吸水性樹脂のママコの有無を観察した。 At the same time, the presence or absence of mamako in the water absorbent resin was observed.
（Ｄ）膨潤ゲルの経時安定性 吸水性樹脂2gを50mlの成人尿で膨潤させ容器内で密閉
し、40℃で16時間放置した。この密閉容器をとりだし、
容器をかたむけてゲルの流動性を調べることにより、膨
潤ゲルの経時安定性を以下の３段階で評価した。(D) Stability over time of swollen gel 2 g of water-absorbent resin was swollen with 50 ml of adult urine, sealed in a container, and left at 40 ° C. for 16 hours. Take out this sealed container,
The stability over time of the swollen gel was evaluated on the following three levels by examining the fluidity of the gel by closing the container.
Ｏ…ゲルが流動しない △…ゲルが少し流動する Ｘ…ゲルが流動する 参考例 アクリル酸ナトリウム141部、アクリル酸36.1部およ
びN,N′−メチレンビスアクリルアミド0.093部を脱イオ
ン水329部に溶解し、これに窒素ガスを吹き込んで溶存
酸素を追い出した。このモノマーの水溶液を30℃に保っ
た。次いで過流酸ナトリウム0.5部およびｌ−アスコル
ビン酸0.02部を加えて静置重合し、ゲル状の含水重合体
を得た。O: gel does not flow △: gel flows slightly X: gel flows Reference Example 141 parts of sodium acrylate, 36.1 parts of acrylic acid and 0.093 part of N, N'-methylenebisacrylamide are dissolved in 329 parts of deionized water. Then, nitrogen gas was blown into this to expel dissolved oxygen. The aqueous solution of this monomer was kept at 30 ° C. Next, 0.5 parts of sodium perfluate and 0.02 parts of l-ascorbic acid were added and the mixture was left to stand for polymerization to obtain a gel-like hydropolymer.
これを150℃の熱風乾燥後、ハンマー型粉砕機にて粉
砕し、20メッシュ通過物の吸水性樹脂粉末（ａ）を得
た。吸水性樹脂粉末（ａ）中の残存モノマーは210ppmで
あった。なお、吸水性樹脂粉末（ａ）の含水率は６％で
あった。This was dried with hot air at 150 ° C. and then pulverized with a hammer type pulverizer to obtain a water-absorbent resin powder (a) having passed through a 20 mesh. The residual monomer in the water-absorbent resin powder (a) was 210 ppm. The water content of the water-absorbent resin powder (a) was 6%.
実施例１ 架橋剤としてトリメチロールプロパン４部、還元性物
質として亜硫酸水素ナトリウム0.2部を水10部イソプロ
パノール３部に溶解した水性液を調整した。Example 1 An aqueous liquid was prepared by dissolving 4 parts of trimethylolpropane as a crosslinking agent and 0.2 parts of sodium hydrogen sulfite as a reducing substance in 10 parts of water and 3 parts of isopropanol.
参考例１で得た吸水性樹脂粉末（ａ）100部と上記水
性液を高速回転パドル型混合機を用いて混合し室温に20
分間放置した後、攪拌下180℃で30分間加熱処理するこ
とにより本発明の吸水性樹脂（１）を得た。得られた樹
脂の物性等を前記の方法で測定し、その結果を第１表に
示す。100 parts of the water-absorbent resin powder (a) obtained in Reference Example 1 and the above aqueous liquid were mixed using a high-speed rotary paddle-type mixer and brought to room temperature.
After standing for 30 minutes, the mixture was heated at 180 ° C. for 30 minutes with stirring to obtain the water-absorbent resin (1) of the present invention. Physical properties and the like of the obtained resin were measured by the methods described above, and the results are shown in Table 1.
実施例２ 架橋剤としてエチレングリコールジグリシジルエーテ
ル0.1部、還元性物質として亜硫酸ナトリウム0.1部を水
20部、イソプロパノール５部に溶解した水性液を調整し
た。Example 2 0.1 part of ethylene glycol diglycidyl ether as a cross-linking agent and 0.1 part of sodium sulfite as a reducing substance in water
An aqueous liquid dissolved in 20 parts and 5 parts of isopropanol was prepared.
参考例１で得た吸水性樹脂粉末（ａ）100部と上記水
性液を高速回転パドル型混合機を用いて混合し室温に25
分放置後、攪拌下120℃で40分間加熱処理することによ
り本発明の吸水性樹脂（２）を得た。得られた樹脂の物
性等を前記の方法で測定し、その結果を第１表に示す。100 parts of the water-absorbent resin powder (a) obtained in Reference Example 1 and the above-mentioned aqueous liquid were mixed using a high-speed rotary paddle-type mixer and brought to room temperature.
After standing for a minute, the mixture was heated at 120 ° C. for 40 minutes with stirring to obtain a water-absorbent resin (2) of the present invention. Physical properties and the like of the obtained resin were measured by the methods described above, and the results are shown in Table 1.
実施例３ 架橋剤として1.6−ヘキサンジオール４部、還元性物
質として亜硫酸水素ナトリウム0.05部を水30部、エタノ
ール４部に溶解した水性液を調整した。Example 3 An aqueous liquid was prepared by dissolving 4 parts of 1.6-hexanediol as a crosslinking agent and 0.05 part of sodium hydrogen sulfite as a reducing substance in 30 parts of water and 4 parts of ethanol.
参考例１で得た吸水性樹脂粉末（ａ）100部と上記水
性液を高速回転パドル型混合機を用いて混合し室温で15
分放置した後、攪拌下180℃で40分間加熱処理すること
により本発明の吸水性樹脂（３）を得た。得られた樹脂
の物性等を前記の方法で測定し、その結果を第１表に示
す。100 parts of the water-absorbent resin powder (a) obtained in Reference Example 1 and the above aqueous liquid were mixed using a high-speed rotary paddle type mixer, and the mixture was added at room temperature for 15 minutes.
After standing for minutes, the mixture was heated at 180 ° C. for 40 minutes with stirring to obtain a water-absorbent resin (3) of the present invention. Physical properties and the like of the obtained resin were measured by the methods described above, and the results are shown in Table 1.
実施例４ 架橋剤としてポリグリセリン５部、還元性物質として
アンモニア0.3部を水15部、エタノール３部に溶解した
水性液を調整した。Example 4 An aqueous liquid prepared by dissolving 5 parts of polyglycerin as a crosslinking agent, 15 parts of ammonia as a reducing substance in 15 parts of water, and 3 parts of ethanol was prepared.
参考例１で得た吸水性樹脂粉末（ａ）100部と上記水
性液を高速回転パドル型混合機を用いて混合し室温に30
分放置した後、攪拌下180℃で40分間加熱処理すること
により本発明の吸水性樹脂（４）を得た。得られた樹脂
の物性等を前記の方法で測定し、その結果を第１表に示
す。100 parts of the water-absorbent resin powder (a) obtained in Reference Example 1 and the above aqueous liquid were mixed using a high-speed paddle-type mixer, and the mixture was cooled to room temperature.
After standing for minutes, the mixture was heated at 180 ° C. for 40 minutes with stirring to obtain a water-absorbent resin (4) of the present invention. Physical properties and the like of the obtained resin were measured by the methods described above, and the results are shown in Table 1.
実施例５ 架橋剤としてグリセリン２部、還元性物質として亜硫
酸ナトリウム0.07部を水８部、イソプロパノール２部に
溶解した水性液を調整した。Example 5 An aqueous liquid was prepared by dissolving 2 parts of glycerin as a crosslinking agent and 0.07 part of sodium sulfite as a reducing substance in 8 parts of water and 2 parts of isopropanol.
参考例１で得た吸水性樹脂（ａ）100部と上記水性液
を高速パドル型混合機を用いて混合し室温に10分放置し
た後、攪拌下180℃で30分間加熱処理することにより本
発明の吸水性樹脂（５）を得た。得られた樹脂の物性等
を前記の方法で測定し、その結果を第１表に示す。100 parts of the water-absorbent resin (a) obtained in Reference Example 1 and the above aqueous liquid were mixed using a high-speed paddle-type mixer, allowed to stand at room temperature for 10 minutes, and then heat-treated at 180 ° C for 30 minutes with stirring. The water-absorbent resin (5) of the invention was obtained. Physical properties and the like of the obtained resin were measured by the methods described above, and the results are shown in Table 1.
比較例１ 実施例１において亜硫酸水素ナトリウムを用いない他
は同様の操作を行ない比較用吸水性樹脂（１）を得た。
得られた樹脂の物性等を前記の方法で測定し、その結果
を第１表に示す。Comparative Example 1 A comparative water-absorbent resin (1) was obtained in the same manner as in Example 1, except that sodium bisulfite was not used.
Physical properties and the like of the obtained resin were measured by the methods described above, and the results are shown in Table 1.
比較例２ 実施例１において架橋剤のトリメチロールプロパンを
用いない水性液と吸水性樹脂粉末（ａ）とを高速回転パ
ドル型混合機を用いて混合後、110℃で30分間加熱する
ことにより比較用吸水性樹脂（２）を得た。得られた樹
脂の物性等を前記の方法で測定し、その結果を第１表に
示す。Comparative Example 2 Comparative Example 1 was repeated by mixing an aqueous liquid without using the cross-linking agent trimethylolpropane and the water-absorbent resin powder (a) with a high-speed rotating paddle-type mixer and then heating at 110 ° C. for 30 minutes. Water absorbent resin (2) was obtained. Physical properties and the like of the obtained resin were measured by the methods described above, and the results are shown in Table 1.
比較例３ 比較例１で得られた比較用吸水性樹脂（１）100部
と、亜硫酸水素ナトリウム0.2部を水50部に溶解させた
水溶液を高速回転パドル型混合機により混合し、さらに
120℃で１時間加熱することにより比較用吸水性樹脂
（３）を得た。得られた樹脂の物性等を前記の方法で測
定し、その結果を第１表に示す。Comparative Example 3 100 parts of the comparative water-absorbent resin (1) obtained in Comparative Example 1 and an aqueous solution in which 0.2 part of sodium bisulfite was dissolved in 50 parts of water were mixed by a high-speed rotary paddle-type mixer.
By heating at 120 ° C. for 1 hour, a comparative water absorbent resin (3) was obtained. Physical properties and the like of the obtained resin were measured by the methods described above, and the results are shown in Table 1.
比較例４ 比較例２で得られた比較用吸水性樹脂（２）100部に
トリメチロールプロパン４部、水10部、イソプロパノー
ル３部からなる水性液を高速パドル型混合機を用いて混
合した後、攪拌下180℃で30分間加熱処理することによ
り比較用吸水性樹脂（４）を得た。得られた樹脂の物性
等を前記の方法で測定し、その結果を第１表に示す。Comparative Example 4 An aqueous liquid composed of 4 parts of trimethylolpropane, 10 parts of water and 3 parts of isopropanol was mixed with 100 parts of the comparative water absorbent resin (2) obtained in Comparative Example 2 using a high-speed paddle type mixer. The mixture was heated at 180 ° C. for 30 minutes with stirring to obtain a comparative water absorbent resin (4). Physical properties and the like of the obtained resin were measured by the methods described above, and the results are shown in Table 1.
比較例５ 実施例１において水を60部に変更した他は同様の操作
を行ない比較用吸水性樹脂（５）を得た。得られた樹脂
の物性等を前記の方法で測定し、その結果を第１表に示
す。Comparative Example 5 A comparative water-absorbent resin (5) was obtained in the same manner as in Example 1, except that water was changed to 60 parts. Physical properties and the like of the obtained resin were measured by the methods described above, and the results are shown in Table 1.
比較例６ 実施例１において水を３部に変更した他は同様の操作
を行ない比較用吸水性樹脂（６）を得た。得られた樹脂
の物性等を前記の方法で測定し、その結果を第１表に示
す。Comparative Example 6 A comparative water-absorbent resin (6) was obtained in the same manner as in Example 1 except that water was changed to 3 parts. Physical properties and the like of the obtained resin were measured by the methods described above, and the results are shown in Table 1.
（発明の効果） 本発明によれば、吸収倍率、加圧下の吸収倍率、吸引
力等吸水諸特性に著しく優れ、かつ残存モノマーも著し
く低減された吸水性樹脂が、架橋剤と還元性物性を同時
に溶解させた特定量の水を含む水性液を吸水性樹脂粉末
と混合し、加熱処理するという操作により初めて製造す
ることができることが明かになった。 (Effects of the Invention) According to the present invention, a water-absorbing resin having excellent water absorption properties such as an absorption capacity, an absorption capacity under pressure, and a suction force, and also having a remarkably reduced residual monomer, has a crosslinking agent and a reducing physical property. At the same time, it has been clarified that an aqueous liquid containing a specific amount of water dissolved therein can be mixed with a water-absorbent resin powder and subjected to heat treatment to produce the first liquid.
また本発明によれば、混合後吸水性樹脂中に添加され
た還元性物質の近傍に架橋剤も分布するため、還元性物
質の種類や量を変化させても膨潤時にも経時安定質の高
い吸水性樹脂を安定に製造することができる。Further, according to the present invention, since the crosslinking agent is also distributed in the vicinity of the reducing substance added to the water-absorbing resin after mixing, even when the type or amount of the reducing substance is changed, even when swollen, the stability with time is high. A water-absorbing resin can be manufactured stably.
従って、本発明により得られる吸水性樹脂は、その特
徴を生かして使い捨ておむつや生理用ナプキン等の衛生
材料の吸収剤、医療用保水剤、濃園芸保水剤、その他諸
工業用脱水剤の吸水性や保水性を必要とする用途に好適
に利用することができる。Therefore, the water-absorbent resin obtained by the present invention, taking advantage of its features, absorbents for sanitary materials such as disposable diapers and sanitary napkins, medical water retention agents, horticultural water retention agents, and water absorption of other industrial dehydrating agents It can be suitably used for applications requiring water retention and water retention.
第１図は吸水性樹脂の加圧下吸収倍率の測定装置の説明
用断面図である。 １……ビュレット ２……ビュレットの上口 ３……栓 ４……測定台 ５……空気孔 ６……ガラスフィルター 7.7′……濾紙 ８……おもり ９……吸水性樹脂FIG. 1 is a sectional view for explaining an apparatus for measuring the absorption capacity of a water-absorbent resin under pressure. DESCRIPTION OF SYMBOLS 1 ... Burette 2 ... Upper end of burette 3 ... Plug 4 ... Measurement table 5 ... Air hole 6 ... Glass filter 7.7 '... Filter paper 8 ... Weight 9 ... Water absorbent resin
───────────────────────────────────────────────────── フロントページの続き (72)発明者 入江 好夫 兵庫県姫路市網干区興浜字西沖992番地 の１ 日本触媒化学工業株式会社姫路研 究所内 (72)発明者 藤原 晃明 兵庫県姫路市網干区興浜字西沖992番地 の１ 日本触媒化学工業株式会社姫路研 究所内 (56)参考文献 特開 昭64−62317（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) C08F 8/00 - 8/14 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoshio Irie 992, Nishioki, Okahama-ku, Himeji-shi, Hyogo Pref. Address No. 1 Himeji Laboratory, Nippon Shokubai Chemical Industry Co., Ltd. (56) References JP-A-64-62317 (JP, A) (58) Fields investigated (Int. Cl. 7 , DB name) C08F 8/00- 8/14
Claims (12)
（１）100重量部に、カルボキシル基と反応し得る官能
基を２個以上有する架橋剤（２）および還元性物質
（３）を溶解させた５〜50重量部の水を含有する水性液
を混合し、加熱することを特徴とする吸水性樹脂（５）
の製造方法。1. A crosslinking agent (2) having at least two functional groups capable of reacting with a carboxyl group and a reducing substance (3) are dissolved in 100 parts by weight of a water-absorbent resin powder having a carboxyl group (1). A water-absorbent resin characterized by mixing and heating an aqueous liquid containing 5 to 50 parts by weight of water (5)
Manufacturing method.
（１）100重量部に、カルボキシル基と反応し得る官能
基を２個以上有する架橋剤（２）0.01〜10重量部および
還元性物質（３）0.001〜５重量部を溶解させた５〜50
重量部の水を含有する水性液を混合し、60〜250℃の温
度で加熱処理することを特徴とする請求項１に記載の方
法。2. A cross-linking agent having two or more functional groups capable of reacting with a carboxyl group per 100 parts by weight of a water-absorbent resin powder having a carboxyl group (1), 0.01 to 10 parts by weight of a cross-linking agent (2) and a reducing substance (3) 5) 50 to 50 parts by weight of 0.001 to 5 parts by weight
The method according to claim 1, wherein an aqueous liquid containing parts by weight of water is mixed and heat-treated at a temperature of 60 to 250C.
載の方法。3. The method according to claim 1, wherein the aqueous liquid contains a hydrophilic organic solvent.
水を７〜30重量部と親水性有機溶剤を0.5〜８重量部の
割合で用いる請求項１記載の方法。4. A water-absorbent resin powder (1) based on 100 parts by weight
The method according to claim 1, wherein water is used in a ratio of 7 to 30 parts by weight and a hydrophilic organic solvent is used in a ratio of 0.5 to 8 parts by weight.
％以下である請求項４記載の方法。5. The method according to claim 4, wherein the proportion of the hydrophilic organic solvent in the aqueous liquid is 40% by weight or less.
硫酸水素塩である請求項１記載の方法。6. The method according to claim 1, wherein the reducing substance (3) is sulfite (salt) or bisulfite.
たは多価グリシジル化合物である請求項１記載の方法。7. The method according to claim 1, wherein the crosslinking agent (2) is a polyhydric alcohol compound or a polyhydric glycidyl compound.
る請求項７記載の方法。8. The method according to claim 7, wherein the crosslinking agent (2) is a polyhydric alcohol compound.
８記載の方法。9. The method according to claim 8, wherein the heat treatment is performed at a temperature of 90 to 230 ° C.
われる請求項１記載の方法。10. The method of claim 1, wherein the mixing is performed by a high speed paddle type mixer.
（１）100重量部に、カルボキシル基と反応し得る官能
基を２個以上有する架橋剤（２）0.01〜10重量部、還元
性物質（３）および水５〜50重量部を混合し、60〜250
℃で加熱架橋することを特徴とする吸水性樹脂（５）の
製造方法。11. A carboxyl group-containing water-absorbent resin powder (1) 100 parts by weight of a crosslinking agent (2) having at least two functional groups capable of reacting with a carboxyl group (2) 0.01 to 10 parts by weight, a reducing substance (3) ) And 5 to 50 parts by weight of water,
A method for producing a water-absorbent resin (5), characterized in that the composition is crosslinked by heating at a temperature of ° C.
（１）100重量部に、カルボキシル基と反応し得る官能
基を２個以上有する架橋剤（２）0.01〜10重量部および
還元性物質（３）0.001〜５重量部を溶解させた５〜50
重量部の水を含有する水性液を混合し、60〜250℃の温
度で加熱処理することを特徴とする請求項11に記載の方
法。12. A cross-linking agent having two or more functional groups capable of reacting with a carboxyl group per 100 parts by weight of a water-absorbent resin powder having a carboxyl group (1), 0.01 to 10 parts by weight of a cross-linking agent (2) and a reducing substance (3) 5) 50 to 50 parts by weight of 0.001 to 5 parts by weight
The method according to claim 11, wherein an aqueous liquid containing parts by weight of water is mixed and heat-treated at a temperature of 60 to 250 ° C.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2223705A JP3068840B2 (en) | 1990-08-24 | 1990-08-24 | Method for producing water absorbent resin |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2223705A JP3068840B2 (en) | 1990-08-24 | 1990-08-24 | Method for producing water absorbent resin |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH04106108A JPH04106108A (en) | 1992-04-08 |
| JP3068840B2 true JP3068840B2 (en) | 2000-07-24 |
Family
ID=16802371
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2223705A Expired - Fee Related JP3068840B2 (en) | 1990-08-24 | 1990-08-24 | Method for producing water absorbent resin |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3068840B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US11198768B2 (en) | 2016-03-11 | 2021-12-14 | Lg Chem, Ltd. | Preparation method of super absorbent polymer |
Families Citing this family (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| TW256840B (en) | 1992-06-10 | 1995-09-11 | Nippon Catalytic Chem Ind | |
| JPH08154514A (en) * | 1994-12-06 | 1996-06-18 | Nippon Shokubai Co Ltd | Excreta-treating material for breeding animal and its production |
| DE19909838A1 (en) * | 1999-03-05 | 2000-09-07 | Stockhausen Chem Fab Gmbh | Powdery, crosslinked, aqueous liquids and blood-absorbing polymers, processes for their preparation and their use |
| WO2002100451A2 (en) | 2001-06-08 | 2002-12-19 | Nippon Shokubai Co., Ltd. | Water-absorbing agent, its production and sanitary material |
| SG159540A1 (en) * | 2005-02-15 | 2010-03-30 | Nippon Catalytic Chem Ind | Water absorbing agent, water absorbing article and method for production of water absorbing agent |
| TWI383008B (en) | 2005-08-17 | 2013-01-21 | Nippon Catalytic Chem Ind | Production method of water-absorbent resin, water-absorbent resin, and usage of water-absorbent resin |
| JP5322538B2 (en) * | 2008-08-29 | 2013-10-23 | 三洋化成工業株式会社 | Absorbent resin for deodorant and / or fragrance |
| JP5473369B2 (en) * | 2009-03-30 | 2014-04-16 | 三洋化成工業株式会社 | Water absorbent resin for pet sheet and pet sheet using the same |
| KR101782501B1 (en) | 2014-12-10 | 2017-09-27 | 주식회사 엘지화학 | Preparation method for super absorbent polymer |
| KR101857702B1 (en) * | 2015-12-23 | 2018-05-14 | 주식회사 엘지화학 | Preparation method of super absorbent polymer |
| EP3878872A4 (en) * | 2018-11-07 | 2022-08-10 | Nippon Shokubai Co., Ltd. | Method for producing particulate water absorbent, and particulate water absorbent |
-
1990
- 1990-08-24 JP JP2223705A patent/JP3068840B2/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US11198768B2 (en) | 2016-03-11 | 2021-12-14 | Lg Chem, Ltd. | Preparation method of super absorbent polymer |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH04106108A (en) | 1992-04-08 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US5597873A (en) | Superabsorbent polymers and products therefrom | |
| US5322896A (en) | Process for producing improved water absorbing resin and resin made by the same | |
| EP1456259B1 (en) | Acrylic acid composition and its production process, and process for producing water-absorbent resin using this acrylic acid composition, and water-absorbent resin | |
| US6969750B2 (en) | Water absorbent material and absorbent article using same | |
| EP2116572B1 (en) | Granulated water absorbent containing water-absorbing resin as the main component | |
| US5447727A (en) | Water-absorbent polymer having improved properties | |
| JP3068840B2 (en) | Method for producing water absorbent resin | |
| JP2011214016A (en) | Water-absorbent resin, and method for producing the same and application | |
| JP2877255B2 (en) | Manufacturing method of water absorbent resin with excellent durability | |
| JPH06287220A (en) | Production of water-absorbable resin | |
| JPH11310644A (en) | Production of water-absorbing agent | |
| JP3202767B2 (en) | Manufacturing method of water absorbing agent | |
| JPH0615574B2 (en) | Method for producing water absorbent resin | |
| JP2002201290A (en) | Water-absorbing resin and its preparation process | |
| JPS61211305A (en) | Production of highly water-absorptive polymer | |
| JP2930555B2 (en) | Method for producing water absorbent resin | |
| JPH02153903A (en) | Production of highly hygroscopic resin | |
| JPH0655838B2 (en) | Surface treatment method for water absorbent resin | |
| JP2944447B2 (en) | Water absorbing agent and method for producing the same | |
| JPH04120176A (en) | Water absorbing agent and production thereof | |
| JPH06200046A (en) | Preparation of modified highly water-absorptive resin and resin | |
| JP2881739B2 (en) | Method for producing water absorbent resin | |
| JP4860019B2 (en) | Water-absorbing agent and production method and use thereof | |
| JP5329023B2 (en) | Surface treatment method for water absorbent resin | |
| JP2001192464A (en) | Surface-cross-linked water-absorbing resin and method for cross-linking surface of water-absorbing resin |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20080519 Year of fee payment: 8 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20090519 Year of fee payment: 9 |
|
| LAPS | Cancellation because of no payment of annual fees |