Ϊ288026 玖、發明說明： 【發明所屬之技術領域】 本發明係關於一種防止吸水性樹脂著色之方法。更詳細 而言’係關於一種適合做為紙尿布及生理用衛生棉等衛生 材料之吸收性物品之吸水劑用吸水性樹脂之著色防止方 法。 【先前技術】 吸水性樹脂活用「將水系液體例如人尿、血液及汗等體 液迅速且大量地吸收，且即使荷重下，亦不會將已吸收: 液體放出」之特徵，而被廣泛用於紙尿布及生理用衛生棉 等衛生材料之吸收性物品中，做為吸水劑。 先前之吸水性樹脂，有「放置中由於熱或溼度等外在因 素，容易著色為黃色或茶色」之問題。尤其，上述衛生材 料之領域中，紙尿布及生理用衛生棉等吸收性物品中之吸 水性樹脂著色時，顯著地降低做為吸收性物品之商品價 值。因此，吸收性物品中所使用之吸水性樹脂，即使在如 夏子>§庫内咼溫尚滢之嚴酿環境中放置時，吸水性樹脂亦 不會著色者，正為各方所尋求。 具有著色防止效果之吸水性樹脂，已知有例如於高吸水 性聚合體中添加有機磷酸化合物或其鹽之高吸水性聚合體 組合物（特開平5-8625 1號公報）、含有酸性水膨潤***聯聚 合體及鹼性水膨潤***聯聚合體、著色防止劑及/或氧化防 止劑及/或硼化合物所形成之吸水劑組合物（特開 2000-230129號公報）、及從吸水性樹脂與羧酸類及/或其鹽 82963 1288026 形成之吸水劑組合物（特開2〇〇〇_327926號公報）等。然而， 上述組合物，在高溫高溼下長期放置時，亦無法發揮充分 令人滿意之效果。 本發明之目的，係提供在高溫高溼下長期放置時亦可抑 制著色之防止吸水性樹脂著色之方法。 此等本發明之目的及其他目的，從以下之記載可以明瞭。 【發明内容】 亦即，本發明係關於： π]—種防止吸水性樹脂著色之方法，其特徵為在以不飽 和幾酸做為必需單體之吸水性樹脂製造方法中，於至少且 任思一步驟體系内或製造後之吸水性樹脂中，添加胺基羧 ^系金屬螯合劑；以及 [2] 種為防止得到之吸水性樹脂著色而使用胺基叛酸 系金屬螯合劑之方法，其特徵為在以不飽和羧酸做為必需 單體之吸水性樹脂之製造方法中，於至少且任意一步驟體 系内或製造後之吸水性樹脂中，添加胺基羧酸系金屬螯合 劑。 【實施方式】 為實施本發明之最佳形態 本發明之防止吸水性樹脂著色之方法，其特徵為在以不 飽和羧酸做為必需單體之吸水性樹脂之製造方法中，於至 少且任意一步驟體系内或製造後之吸水性樹脂中，添加胺 基Jk fei系金屬螯合劑，以致在高溫南逢下放置時亦可抑制 吸水性樹脂著色。 82963 1288026 本發明所使用之胺基叛酸系金屬螯合劑，例如為亞胺基 二醋酸、羥乙基亞胺基二醋酸、氮川三醋酸、氮川三丙酸、 伸乙基一胺四酷酸、二伸乙基三胺五醋·酸、三伸乙基四胺 六醋酸、反·1，2-二胺基環己基四醋酸、n，N-貳（2-羥乙基） 甘胺酸、二胺基丙醇四醋酸、伸乙基二胺二丙酸、經基伸 乙基二胺三醋酸、二醇醚二胺四醋酸、二胺基丙基四醋酸、 N，N’-貳（2-羥苄基）伸乙基二胺_N，N，_二醋酸、丨，6_六亞甲基 二胺-N，N，N’，N’-四醋酸及其鹽等。其中從具有著色防止效 果之觀點而言，以使用二伸乙基三胺五醋酸、三伸乙基四 胺六酷酸、反-1，2-二胺基環己基四醋酸及其鹽為較佳。 在製造吸水性樹脂之任一步驟體系内或製造後之吸水性 樹脂中添加胺基羧酸系金屬螯合劑之方法，如將上述胺基 叛酸系金屬螯合劑（A)添加於聚合前之含有不飽和羧酸之 單體水溶液之方法，（B)添加於聚合後之含水凝膠狀物之方 法，（C)添加於乾燥中之吸水性樹脂之方法、（D)與乾燥後 之吸水性樹脂進行粉體混合之方法、及（£)添加於分散在有 機溶媒之吸水性樹脂中，並加熱及脫溶媒之方法等。 本發明中，從維持生產性及造成高著色防止效果之觀點 而言，以簡便之方法，將胺基羧酸系金屬螯合劑均勻地分 散在吸水性樹脂中或只分散在吸水性樹脂表面為較佳。為 了使胺基羧酸系金屬螯合劑均勻分散於吸水性樹脂，以（B) 添加於聚合後之含水凝膠狀物之方法，（(：：）添加於乾燥中之 吸水性樹脂之方法，及（D)與乾燥後之吸水性樹脂進 混合之方法為特佳。 把 82963 1288026 添加胺基瘦酸系金屬螯合劑之形態並無特別限定，不過 為使胺基複酸系金屬螯合劑均勻地分散在吸水性樹脂中， 以液體或粉體胺基羧酸系金屬螯合劑溶於水等親水性溶媒 中之溶液形態添加，或將微粉末狀胺基羧酸系金屬螯合劑 以粉末狀態添加為較佳。再者，微粉末狀胺基羧酸系金屬 螯合劑之粒徑並無特別限定，不過從粗粒子部分少較能得 到充分著色防止效果之觀點而言，以全體8〇重量％以上粒 子之粒徑為100 μηι以下為較佳。 上述胺基羧酸系金屬螯合劑之使用量，從可得到充分著 色防止效果且可得到與使用量相稱效果之經濟觀點言之， 對於每100重量份不飽和羧酸，以使用〇 〇〇1〜6重量份為較 佳’而以0.006〜3重量份為更佳，以〇01〜2重量份為最佳。 因此，根據本發明，可提供一種為防止得到之吸水性樹 月曰著色而使用胺基敗系金屬螯合劑之方法，其特徵為在 以不飽和羧酸做為必需單體之吸水性樹脂製造方法中，於 至少且任意一步驟體系内或製造後之吸水性樹脂中，添加 胺基羧酸系金屬螯合劑。 在本％明中製造之以不飽和幾酸做為必需單體之吸水性 树月曰，可為丙烯酸鹽聚合體之交聯物、澱粉_丙烯酸鹽接枝 氷口體之水解生成物之叉聯物、乙缔醇_丙烯酸鹽共聚合 體之交聯物、馬來酸酐接枝聚乙烯醇交聯物、交聯異丁烯_ 馬來酸奸共聚合體、聚丙缔酸部分中和物交聯體、及醋酸 =晞酯-丙締酸酯共聚合體之笔化物等。其中，以可吸收大 量水’且無論施加多少荷重均能將吸收之水保持於分子内 82963 1288026 之丙烯酸鹽聚.合體之交聯物為較佳。 不飽和叛版，例如為丙晞酸、甲基丙稀酸、馬來酸、馬 來酸酐及冨馬酸等。彼等可單獨使用，亦可二種以上混合 使用。不飽和羧酸亦可藉由鹼金屬進行部分中和，其中以 使用丙烯酸、甲基丙烯酸及彼等之鈉鹽或鉀鹽等鹼金屬鹽 為較佳。 上述不飽和羧酸亦可依照需要輿其他單體共聚合。其他 單體，例如為（甲基）丙晞醯胺[「（甲基）丙烯」意指Γ丙烯」 及「甲基丙烯」，以下相同]、N-取代（甲基）丙埽醯胺、（甲 基）丙烯酸2-羥基乙酯、（甲基）丙烯酸2_羥基丙酯、（甲基） 丙烯酸甲氧基聚乙二醇酯、及（甲基）丙烯酸聚乙二醇酯等 含有非離子性親水基之單體，（甲基）丙烯酸N，N_:甲胺基 乙酯、（甲基）丙烯酸N，N-二甲胺基丙酯及N，N-二甲胺丙基 (甲基）丙婦醯胺等含胺基之不飽和單體，乙烯基磺酸、苯 乙缔磺酸、2-(甲基）丙埽醯胺_2_甲基丙磺酸、2_(甲基）丙烯 醯基乙磺酸及彼等之鹽等磺酸系單體等。 上述吸水性樹脂之聚合方法並無特別限定，可使用為代 f性製造方法之逆相懸浮聚合法或水溶液聚合法等。以下 藉由逆相懸浮聚合法舉例說明。 s逆相懸浮聚合法’可在界面活性劑及高分子保護膠體之 :乂 一者存在下，以單體水溶液分散於有機溶媒之狀態， 藉由使用例如聚合起始劑進行聚合。 *上述單體水溶液中之單體濃度，以25重量％〜飽和濃度為 佳又，上述單體水溶液在聚合反應中，可一次添加， 82963 1288026 亦可分次添加。 上述有機A媒可為正戊燒、正己燒、正庚燒或石油鍵等 月㈢肪族fe溶媒’壤戊fe、甲基環戊燒、環己燒或甲基環己 烷等脂環族烴溶媒，或苯、甲苯或二甲苯等芳香族烴溶媒 等。其中，以使用正戊烷或環己烷為較佳。 有機溶媒之使用量，從容易除去聚合熱及控制聚合溫度 之觀點而言，每100重量份單體總量，以用50〜600重量份為 較佳，又以用100〜5 50重量份為更佳。 上述界面活性劑，例如為脂肪酸山梨醇酐酯、單脂肪酸 甘油酯、聚脂肪酸甘油酯、脂肪酸蔗糖酯、聚氧乙浠硬化 蓖麻子油、月桂酸聚氧乙埽硬化蓖麻子油、（三）異硬脂酸 聚氧乙烯硬化蓖麻子油、聚氧乙晞烷基苯基醚、聚氧乙晞 月桂基醚、及聚氧乙烯己基癸基醚等非離子界面活性劑。 上述咼分子保護膠體’例如為乙基纖維素、輕乙基纖維 素、氧化聚乙烯、馬來酸酐化聚乙烯、馬來酸酐化聚丁二 晞及馬來酸纤.化乙烯-丙缔-二烯三元共聚體等。 此等非離子界面活性劑及高分子保護膠體，亦可二種以 上混合使用。 此等非離子界面活性劑及/或高分子保護膠體，亦可與陰 離子界面活性劑併用。陰離子界面活性劑，例如為脂肪酸 鹽、燒基苯磺酸鹽、烷基甲基牛磺酸鹽、聚氧乙烯烷基苯 醚硫酸酯鹽、及聚氧乙錦τ燒基醚績酸鹽等。 界面活性劑及/或高分子保護膠體之使用量，從單體水溶 液充分分散以及得到與使用量相稱效果之經濟觀點而言， 82963 -11- 1288026 每100重量份單體總量，以用0>1〜5重量份為較佳，又以〇 2〜3 重量份為更佳。 上述吸水性樹脂，雖可不使用交聯劑而藉由自行交聯型 反應而合成，然而亦可使用具有二個以上聚合性不飽和基 或一個以上反應性基之内部交聯劑進行交聯。内部交聯 ^例如為N，N’-亞甲基貳（甲基）丙缔醯胺、二（甲基）丙缔 酸乙一醇酯、二（〒基）丙烯酸二聚乙二醇酯、二（甲基）丙埽 酸二聚乙二醇酯、二（甲基）丙稀酸三羥甲基丙基酯、三（甲 基）丙烯酸三羥甲基丙基酯、三（羥甲基丙基）二（甲基）缔丙 基醚或三烯丙基胺等在一個分子中具有2個以上乙缔系不 飽和基之化合物，或（聚）乙二醇二縮水甘油醚及甘油三縮 水甘油醚等聚縮水甘油醚，或表氯醇及表溴醇等自代環氧 化合物等。在考慮聚合系中之反應性及水溶性後，雖可使 用彼等1種或2種以上，不過以使用在一個分子中具有2個以 上縮水甘油基之化合物做為内部交聯劑為較佳。 内部交聯劑之使用量，從得到之吸水性樹脂適度交聯以 抑制水溶性性質且呈現充分吸水性之觀點而言，每1 〇〇重量 份上述單體合總量，以用〇·001〜3重量份為較佳，而以 0.003〜1重量份為更佳，0.005〜5重量份為特佳。 聚合起始劑’例如可為過硫酸鉀、過硫酸鈉、過硫酸銨、 過氧化芊酸基、過氧化氫、1，1，_偶氮貳（環己―丨—腈）、2,2，_ 偶氮貳（2-甲基-丁腈）、2,2’-偶氮貳異丁腈、2,2，-偶氮貳（2-眯基丙燒）二鹽酸鹽、2_氰基-2-丙基偶氮甲醯胺及2,2，-偶氮 貳（2-甲基-丙酸）二甲酯等自由基聚合起始劑。此等自由基 82963 -12- 1288026 聚合起始劑亦可輿亞硫酸鹽等併用，做為氧化還原系聚合 起始劑使用。 聚合起始劑之使用量，從縮短聚合反應時間，防止劇烈 聚合反應以使反應容易控制之觀點而言，每1〇〇莫耳上述單 體總量，以用0.005〜1莫耳為較佳。 將上述界面活性劑及/或高分子保護膠體溶於有機溶媒 中，添加上述單體水溶液及聚合起始劑等，在攪拌下加熱， 於水/油系中進行逆相懸浮聚合。上述聚合反應之反應溫 度，雖隨使用之聚合起始劑及單體種類或單體水溶液之濃 度而異，然而從迅速進行聚合、縮短聚合時間、符合經濟 利盈、容易除去聚合熱及反應平順之觀點而言，以 °C為較佳，而以40〜80A承社 cd Μ ⑽匕為更佳。反應時間，通常 5〜4 小時。 得到之吸水性樹脂，並；I ^__ 八&基斫可與含有二個以上且有反 應性耳能基之交聯劑作用，進 八 延仃表面人聯。表面交聯劑， 可使用能與吸水性樹脂中之 υ細甲芡叙基反應者。例如 醇二縮水甘油醚、（聚）而—辟 、 V永— ^ )丙一％二縮水甘油醚、（ 水甘油鍵及糖醇等環氧化物 縮 产二产卜 表鼠醇、表溴醇及α -甲其矣 鼠醇寺鹵化環氧化合物，1 土表 ^ (來）乙一醇、（聚）丙二醇、d)甘 油、二醇類、戊二醇猶、 — （永）甘 醇胺及=乙醇胺等己二醇類、三羥甲基丙烷、二乙 咚妝夂一乙知胺寺多價醇化八 、 合物為更佳。此等表面丄 ’、 以使用環氧化 併用。 寺表面又聯劑可單獨使用，亦可兩種以上 表面X聯劑之使用量， 处吸水性樹脂吸水時凝膠強度及 82963 -13- 1288026 充分保持吸水量之觀點而言，每100重量份上述單體總量， 以用0.01〜5重量份為較佳，而以0·02〜4重量份為更佳，以 0·03〜3重量份為特佳。 上述表面交聯劑之添加方法，並無特別限定，可為例如 添加在分散於有機溶媒之吸水性樹脂中之方法，或藉由將 吸水性樹脂一面攪拌，一面噴灑等噴霧法等。表面^聯劑 之添加時期，可為聚合後之含水凝膠狀物之階段，乾燥中 之含水粒子階段及乾燥後之階段等。其中，以在聚合後之 含水凝膠狀物階段添加於分散在有機溶媒之吸水性樹脂中 之方法，以及在乾燥中之含水粒子階段，藉由噴灑等噴霧 之方法為較佳。 表面交聯劑之添加形態，並無特別限定，然而為使表面 又聯劑對吸水性樹脂均勻地添加，以將表面交聯劑溶解在 水等親水性溶媒中而添加為較佳。 以下，藉由實施例及比較例詳細地說明本發明，然而本 發明並不僅僅·限定於此等實施例。 實施例1 於備有攪拌機、回流冷卻器、滴入漏斗、溫度計及氮氣 導入管之1000 ml容積之五口圓筒型圓底燒瓶中添加正庚 烷500 ml。在其中添加Hlb為5.0之五硬脂酸十甘油酯（界面 活性劑：太陽化學股份有限公司製，Suns〇ft Q-185S) 1 ·38g ’使其分散’升溫並將界面活性劑溶解後，冷卻至55 〇C。 除上述之外，於500 ml容積之三角燒瓶中，添加8〇重量％ 82963 -14- 1288026 之丙缔酸水溶液92g。將其從外部冷卻，同時將30重量％之 氫氧化鈉水溶液102.2g滴入，以將丙烯酸之75莫耳％中和， 而調製得丙烯酸之部分中和物。然後，添加水50.2g、為聚 合起始劑之過硫酸鉀0· 11 g、以及為交聯劑之乙二醇二縮水 甘油醚18.4 mg，調製得聚合用單體水溶液。 將该聚合用早體水落液’在擾摔下全量加入上述五口 0 筒型圓底燒瓶中並使其分散，將系統内以氮氣充分置換後 升’保持浴溫在7 0 c ’並進行聚合反應1小時。聚合終了 後’於攪拌下添加為胺基羧酸系金屬螯合劑之14重量％反 -1，2-二胺基環己基四醋酸四鈉水溶液〇 66g。然後，藉由共 冻脫水並將水分從含水凝膠狀物中除去，移至系統外。於 得到之凝膠狀物中添加2重量％之乙二醇二縮水甘油醚水 溶液4.14g，再將水分及正庚烷藉由蒸餾除去並乾燥，得到 吸水性樹脂93.0g。 實施例2 於備有攪拌機、回流冷卻器、滴入漏斗、溫度計及氮氣 導入管之1000 ml容積之五口圓筒型圓底燒瓶中添加正庚 烷500 ml。在其中添加HLB為3 〇之脂肪酸蔗糖酯（界面活性 劑·三菱化學股份有限公司製，S-37〇) 〇 92g，並使其分散， 升溫並將界面活性劑溶解後，冷卻至5 51。 除上述之外，於500 ml容積之三角燒瓶中，添加8〇重量％ 之丙缔酸水落液92g。將其從外部冷卻，同時將3〇重量％之 氲氧化鈉水溶液102.2g滴入，以將丙烯酸之75莫耳％中和， 而調製得丙烯酸之部分中和物。然後，添加水5〇2§、為聚 82963 -15- 1288026 合起始劑之過硫酸鉀0· 1 lg、為交聯劑之乙二醇二縮水甘油 駿9.2 mg，調製第一階段聚合用單體水溶液。 將該第一階段聚合用單體水溶液，在攪拌下全量加入上 述五口圓筒型圓底燒瓶中並使其分散，將系統内以氮氣充 分置換後升溫，保持浴溫在70°C，於聚合反應進行丨小時 後，將聚合漿液冷卻至室溫。 然後，另外於500 ml容積之三角燒瓶中，添加8〇重量％ 之丙錦r酸水溶液119· lg，冷卻同時將30重量％之氫氧化納水 溶液1 3 2 · 2 g滴入，以將丙烯酸之7 5莫耳％中和，然後添加水 27.4g、過硫酸鉀〇.l4g、乙二醇二縮水甘油醚35 7 mg，以 〃周製弟一階段聚合用單體水溶液’並將其於冰水浴内冷卻。 將該第二階段聚合用單體水溶液，全量添加於上述聚合 漿液後，再將系統内以氮氣充分置換後升溫，保持浴溫在 70°C，並進行第二階段聚合反應2小時。聚合終了後，在分 散於正庚燒之含水凝膠狀物中，在攪拌下添加為胺基叛酸 系金屬螯合劑之40重量％之二伸乙基三胺五醋酸五鋼水溶 液0 · 5 3 g。然後，藉由共沸脫水並將水分從含水凝膠狀物中 除去，移至系統外。於得到之凝膠狀物中添加2重量％乙二 醇二縮水甘油醚水溶液8.44g，再將水分及正庚烷藉由蒸餾 除去並乾燥，得到吸水性樹脂214.8g。 貫施例3 於備有攪拌機、回流冷卻器、滴入漏斗、溫度計及氮氣 導入管之1000 ml容積之五口圓筒型圓底燒瓶中添加正庚 k 500 ml在其中添加HLB為3 _0之脂防酸蔗糖酯（界面活性 82963 -16- 1288026 劑·三菱化學股份有限公司製，s_37〇) 〇 92g，使其分散， 升溫並將界面活性劑溶解後，冷卻至55。 除上述之外，於500 ml容積之三角燒瓶中，添加8〇重量％ 之丙烯酸水溶液92g。將其從外部冷卻，同時將3〇重量 氳氧化鈉水溶液l〇2.2g滴入，以將丙浠酸之75莫耳％中和， 而調製得丙烯酸之部分中和物。然後，添加水5〇.2§、為聚 占起始劑之過硫酸钾0 · 1 1 g、以及為交聯劑之乙二醇二縮水 甘油醚9.2 mg，調製得聚合用單體水溶液。 將該聚合用單體水溶液，在攪拌下全量加入上述五口圓 筒型圓底燒瓶中並使其分散，將系統内以氮氣充分置換後 升溫’保持浴溫在7〇°C，進行聚合反應1小時。聚合終了後， 藉由共沸脫水並將水分從含水凝膠狀物中除去，移至系統 外。於得到之凝膠狀物中添加2重量％之乙二醇二縮水甘油 酸水溶液4.14g及，再將水分及正庚烷藉由蒸餾除去後，在 授拌下添加為胺基羧酸系金屬螯合劑之粉體三伸乙基四胺 六醋酸（粒子全體之87重量％為1〇〇 μχη以下）0.46g。再加以 乾燥’除去水分及正庚烷，得到吸水性樹脂92.8g。 實施例4 於實施例3中，除不添加三伸乙基四胺六醋酸以外，進行 與實施例3同樣之操作，得到吸水性樹脂92.0g。於聚乙埽 袋内’添加上述吸水性樹脂全量及粉體之二伸乙基三胺五 酷酸二鈉（粒子全體之85重量％粒徑為100 μπι以下）〇.46g且 充分混合，得到吸水性樹脂92 5g。 實施例5 82963 -17- 1288026 於備有攪拌機、回流冷卻器、滴入漏斗、溫度計及氮氣 導入管之1000 ml容積之五口圓筒型圓底燒瓶中添加正庚 燒500 m卜在其中添加HLB為4.7之單硬脂酸山梨醇酐酯（界 面活性劑：日本油脂股份有限公司製，N〇ni〇n SP_60R) 0 · 9 2 g ’使其分散，升溫並將界面活性劑溶解後，冷卻至π °C。 除上述之外’於500 ml容積之三角燒瓶中，添加8〇重量0/〇 之丙烯酸水溶液92g。將其從外部冷卻，同時將3〇重量％之 氫氧化鈉水溶液102·2g滴入，以將丙烯酸之75莫耳％中和， 而碉製得丙烯酸之部分中和物。更且，添加水2〇 8§、為聚 合起始劑之過硫酸鉀0.11 g、為交聯劑之N，N，_亞甲基貳丙烯 醯胺23.0 mg。更於其中添加為胺基羧酸系金屬螯合劑之4〇 重量％二伸乙基三胺五醋酸五鈉水溶液〇23g，以調製聚合 用單體水溶液。 將Μ聚合用單體水溶液，在攪拌下全量加入上述五口圓 筒型圓底燒瓶中並使其分散，將系統内以氮氣充分置換後 升溫，保持浴溫在70 C，進行聚合反應2小時。聚合終了後， 藉由共沸脫水並將水分從含水凝膠狀物中除去，移至系統 外。於得到之凝膠狀物中添加2重量％之乙二醇二縮水甘油 醚水/谷液4_60g，再將水分及正庚烷藉由蒸餾除去並乾燥， 得到吸水性樹脂93.8g。 實施例6 •於備有㈣機、回流冷卻器、滴人漏斗、溫度計及氮氣 導入管< 1500 ml容積之五口圓筒型圓底燒瓶中添加正庚 82963 -18- 1288026 烷550 m卜在其中添加HLB為8·6之單月桂酸山梨醇酐酯（界 面活性劑：日本油脂股份有限公司製，N〇ni〇n Lp_2〇R) 0.84g，使其分散，升溫並將界面活性劑溶解後，冷卻至恥。[。 除上述之外，於500 ml容積之三角燒瓶中，添加8〇重量％ 芡丙烯酸水溶液70g。將其從外部冷卻，同時將3〇重量％之 氫氧化鈉水落液77.8g滴入，以將丙缔酸之75莫耳％中和， 調製得丙烯酸之部分中和物。然後，添加水33坫以及為聚 合起始劑之過硫酸鉀〇.〇84g，調製得聚合用單體水溶液。 將該聚合用單體水溶液，在攪拌下全量加入上述五口圓 筒型圓底燒瓶中並使其分散，將系統内以氮氣充分置換後 升溫，保持浴溫在7〇°C，進行聚合反應3小時。聚合終了後， 在含水凝膠狀物中，於攪拌下添加為胺基羧酸系金屬螯合 J之40重昼/〇之一伸乙基二胺五酷酸五鈉水溶液〇· 1乃然 後，藉由共沸脫水並將水分從含水凝膠狀物中除去，移至 系統外。於得到之凝膠狀物中添加2重量％之乙二醇二縮水 甘油醚水溶液3.15g,再將水分及正庚烷藉由蒸餾除去並乾 燥，得到吸水性樹脂74.〇g。 實施例7 除添加38重量％伸乙基二胺四醋酸四鈉水溶液1.21 g代替 貫知例5中之一伸乙基三胺五酷酸五#9以外，進行與實施例 5同樣之操作，得到吸水性樹脂93 ·6g。 比較例1 除不添加實施例丨中之胺基羧酸系金屬螯合劑之外，進行 與實施例1同樣之操作，得到吸水性樹脂92.1 g。 82963 -19- 1288026 比較例2 除不添加實施例2中之胺基羧酸系金屬螯合劑之外，進行 與實施例2同樣之操作，得到吸水性樹脂2 1 2.5g。 比較例3 除不添加實施例3中之胺基羧酸系金屬螯合劑之外，進行 與貫施例3同樣之操作，得到吸水性樹脂92· 1 g。 比較例4 除添加檸檬酸〇.92g溶於水9.2g之水溶液以代替實施例1 中之反·1，2-二胺基環己基四醋酸四鈉之外，進行與實施例i 同樣之操作，得到吸水性樹脂92·8g。 比較例5 除添加三聚磷酸鈉（粒子全體之90重量％為1 〇〇 pm以 下）0.46g代替實施例3中之三伸乙基四胺六醋酸之外，進行 與實施例3同樣之操作，得到吸水性樹脂92.6g。 上述實施例及比較例中得到之吸水性樹脂之著色試驗， 係藉由以下之方法進行。 [吸水性樹脂之著色試驗] 將吸水性樹脂2.0g均句地加入内徑3 cm，深度1 cm之聚 丙晞製容器中。將此容器於設定為溫度5〇±2°c，相對溼度 90±2%RH之桌上型恆溫恆溼槽内放置2〇日。放置後，從怪 溫怪歷槽内將容器取出，短暫放置後冷卻至室溫。於内徑3 cm之玻璃製測定容器中，將容器内之吸水性樹脂全量加 入，再以標準用白板進行測色色差計三感應值χ、¥及2之 校正，且採用雙光束交照測光方式之測色色差計1⑼1 dp 82963 -20 - 1288026 (日本電色工業股份有限公司製）測定吸水性樹脂之黃色 度。從得到之吸水性樹脂之X、Y及Z(三感應值），藉由下式 算出黃色度。同樣地，求取在桌上型恆溫恆溼槽内放置20 日之試驗前吸水性樹脂之黃色度。再者，進行上述測定三 次，並使用其之平均值。 黃色度=100(1·28Χ-1·06Ζ)/Υ 上述實施例中使用之胺基羧酸系金屬螯合劑，及上述實 施例及比較例中得到之吸水性樹脂之著色試驗結果如表1 所示。再者，表1中括旅内之量為相對於丙晞酸100重量份 之量。 表1 胺基羧酸系金屬螯合劑 著色試驗結果 種類(重量份） 試驗前 黃色度 試驗後 黃色度 黃色 度之差 實施例1 反-1，2-二胺基環己基四醋酸四鈉(0.126) 9.5 12.6 3.1 實施例2 二伸乙基三胺五醋酸五鈉(0.125) 9.7 12.9 3.2 實施例3 三伸乙基四胺六酷酸(0.625) 9.9 12.9 3.0 實施例4 二伸乙基三胺五醋酸二鈉(0.625) 10.1 13.1 3.0 實施例5 二伸乙基三胺五醋酸五鈉(0.125) 9.8 12.8 3.0 實施例6 二伸乙基三胺五醋酸五鈉(0.125) 5.5 7.0 1.5 實施例7 伸乙基二胺四醋酸四鈉(〇·625) 10.0 15.9 5.9 比較例1 (無添加） 10.8 21.9 11.1 比較例2 (無添加） 10.4 21.1 10.7 82963 -21 - 1288026 比較例3 (無添加） 10.2 21.5 11.3 比較例4 擰檬酸(1.25) 10.0 20.7 10.7 比較例5 三聚磷酸鈉(0.625) 9.9 20.0 10.1 從表1可知，實施例中得到之添加胺基羧酸系金屬螯合劑 之吸水性樹脂，試驗前與試驗後之黃色度變化少，著色被 抑制。與此相對地，比較例中得到之未添加胺基羧酸系金 屬螯合劑之吸水性樹脂，黃色度變化大，有相當程度之著 色。 產業上利用之可能性 若根據本發明，藉由在胺基羧酸系螯合劑存在下製造吸 水性樹脂，即使在高溫高溼之嚴苛環境條件下，亦矸抑剎 吸水性樹脂之著色。 、如以上所述，本發明顯然在同一性質之範圍内以多種形 式存Ί種多樣性並未脫離本發明之意圖及範園，本技 藝人士顯而易知之所有變更，均包含於以下申請專利範園 之技術範圍内。 82963 -22-Ϊ288026 发明, invention description: TECHNICAL FIELD The present invention relates to a method for preventing coloration of a water-absorbent resin. More specifically, it relates to a coloring prevention method for a water-absorbent resin for a water absorbing agent which is suitable as an absorbent article for sanitary materials such as disposable diapers and sanitary napkins. [Prior Art] The water-absorbent resin is widely used for "using a liquid such as human urine, blood, and sweat to absorb quickly and in a large amount, and does not absorb absorbed liquid even under load." It is used as a water absorbing agent in absorbent articles such as disposable diapers and sanitary napkins. The conventional water-absorbent resin has a problem that it is easily colored in yellow or brown due to external factors such as heat or humidity during standing. In particular, in the field of the above-mentioned sanitary materials, when the water-absorbent resin in absorbent articles such as disposable diapers and sanitary napkins is colored, the commercial value of the absorbent article is remarkably lowered. Therefore, the water-absorbent resin used in the absorbent article is not intended to be colored even when it is placed in a strict environment such as Xia Zi> A water-absorbent resin having a coloring-preventing effect is known, for example, a superabsorbent polymer composition in which an organic phosphoric acid compound or a salt thereof is added to a superabsorbent polymer (Japanese Unexamined Patent Publication No. Hei No. Hei 5-8625) A water absorbing agent composition formed by a cross-linked polymer, an alkaline water-swellable cross-linked polymer, a coloring preventing agent, and/or an oxidation preventing agent and/or a boron compound (JP-A-2000-230129), and a water-absorbent resin A water absorbing agent composition formed by a carboxylic acid and/or a salt thereof 82963 1288026 (Japanese Laid-Open Patent Publication No. Hei No. Hei No. Hei. However, the above composition does not exhibit a sufficiently satisfactory effect when it is left standing for a long period of time under high temperature and high humidity. SUMMARY OF THE INVENTION An object of the present invention is to provide a method for inhibiting coloration of a water-absorbent resin which inhibits coloration when left standing for a long period of time under high temperature and high humidity. The objects and other objects of the present invention will become apparent from the following description. [Invention] The present invention relates to: π] - a method for preventing coloration of a water-absorbent resin, characterized in that at least a method of producing a water-absorbent resin using an unsaturated acid as an essential monomer Adding an aminocarboxylate-based metal chelating agent to the water-absorbent resin in the first step system or after the production; and [2] a method of using an amine-based oxo-based metal chelating agent to prevent coloring of the obtained water-absorbent resin, In the method for producing a water-absorbent resin containing an unsaturated carboxylic acid as an essential monomer, an aminocarboxylic acid-based metal chelating agent is added to the water-absorbent resin in at least one of the steps of the system or after the production. [Embodiment] The method for producing a water-absorbent resin according to the present invention, which is characterized in that, in a method for producing a water-absorbent resin containing an unsaturated carboxylic acid as an essential monomer, at least In the one-step system or the water-absorbent resin after the production, an amine-based Jk fei-based metal chelating agent is added so that the coloring of the water-absorbent resin can be suppressed even when it is placed under high temperature. 82963 1288026 Amino-based acid-reducing metal chelating agent used in the present invention, for example, iminodiacetic acid, hydroxyethyliminodiacetic acid, nitrilotriacetic acid, nitrilotriacetic acid, ethylideneamine Sour acid, di-ethyltriamine pentaacetic acid, tri-ethylidenetetraamine hexaacetic acid, trans-1,2-diaminocyclohexyltetraacetic acid, n,N-indole (2-hydroxyethyl) Amine acid, diaminopropanol tetraacetic acid, ethyldiamine dipropionic acid, ethyldiamine triacetate, glycol ether diamine tetraacetic acid, diaminopropyltetraacetic acid, N, N'- Bis(2-hydroxybenzyl)-extension ethyldiamine_N,N,-diacetic acid, hydrazine, 6-hexamethylenediamine-N,N,N',N'-tetraacetic acid and salts thereof and the like. Among them, from the viewpoint of having a coloring prevention effect, it is more preferable to use di-ethyltriamine pentaacetic acid, tri-extension ethyltetramine hexanoic acid, trans-1,2-diaminocyclohexyltetraacetic acid and salts thereof. good. A method of adding an aminocarboxylic acid-based metal chelating agent to a water-absorbent resin in any one of the steps of producing a water-absorbent resin, such as adding the above-mentioned amino-based acid-removing metal chelating agent (A) to the pre-polymerization a method of adding an aqueous monomer solution of an unsaturated carboxylic acid, (B) a method of adding a hydrogel after polymerization, (C) a method of adding a water-absorbent resin in a dry state, (D), and water absorption after drying A method of mixing a resin with a powder, and (£) a method of adding to a water-absorbent resin dispersed in an organic solvent, heating and desolving the solvent, and the like. In the present invention, the aminocarboxylic acid-based metal chelating agent is uniformly dispersed in the water-absorbent resin or dispersed only on the surface of the water-absorbent resin from the viewpoint of maintaining productivity and causing high coloring prevention effect. Preferably. In order to uniformly disperse the aminocarboxylic acid-based metal chelating agent in the water-absorbent resin, (B) is added to the hydrogel after polymerization, ((::) is added to the water-absorbent resin in the drying method, And (D) is preferably mixed with the water-absorbent resin after drying. The form of adding the amine-based lean acid-based metal chelating agent to 82963 1288026 is not particularly limited, but is to make the amine-based complex acid-based metal chelating agent uniform. Dispersed in a water-absorbent resin, added in the form of a solution in which a liquid or a powdery aminocarboxylic acid-based metal chelating agent is dissolved in a hydrophilic solvent such as water, or a powdery aminocarboxylic acid-based metal chelating agent in a powder state In addition, the particle size of the finely divided aminocarboxylic acid-based metal chelating agent is not particularly limited, but the weight of the coarse particles is less than that of the total coloring prevention effect. It is preferable that the particle diameter of the above-mentioned particles is 100 μm or less. The use amount of the above-mentioned aminocarboxylic acid-based metal chelating agent is economical in view of obtaining a sufficient coloring prevention effect and obtaining an effect proportional to the amount of use. For every 100 parts by weight of the unsaturated carboxylic acid, it is preferably used in an amount of from 1 to 6 parts by weight, more preferably from 0.006 to 3 parts by weight, most preferably from 0.1 to 2 parts by weight. According to the present invention, there is provided a method of using an amine-based metal-based chelating agent for preventing coloring of a water-absorbing tree sap, which is characterized in that, in a method for producing a water-absorbent resin using an unsaturated carboxylic acid as an essential monomer, An aminocarboxylic acid-based metal chelating agent is added to the water-absorbent resin in at least one of the steps of the system or after the production. The water-absorbent tree of the unsaturated acid is used as an essential monomer in the present invention. It may be a crosslinked product of an acrylate polymer, a crosslinked product of a hydrolysis product of a starch-acrylic acid grafted ice mouth body, a crosslinked product of a propylene glycol acrylate composite, and a maleic anhydride grafted polyethylene. Alcohol cross-linking, cross-linked isobutylene _ maleic acid phytochemical, polypropionic acid partial neutralized cross-linking body, acetic acid = oxime ester-propionate copolymer penetide, etc. Water' and no matter how much load is applied, it will suck The water is retained in the molecule 82963 1288026. The acrylate is a crosslinked product of the composite. Unsaturated renegade, such as propionic acid, methyl methic acid, maleic acid, maleic anhydride and humic acid. These may be used singly or in combination of two or more. The unsaturated carboxylic acid may also be partially neutralized by an alkali metal using an alkali such as acrylic acid, methacrylic acid or the like, or a sodium or potassium salt thereof. A metal salt is preferred. The above unsaturated carboxylic acid may be copolymerized with other monomers as needed. Other monomers such as (meth) acrylamide ["(meth) propylene" means propylene" and "Methacrylic", the same as the following], N-substituted (methyl) acrylamide, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, (meth) acrylate a monomer containing a nonionic hydrophilic group such as oxypolyethylene glycol ester and polyethylene glycol (meth)acrylate, N,N_:methylaminoethyl (meth)acrylate, (meth)acrylic acid N,N-dimethylaminopropyl ester and N,N-dimethylaminopropyl (methyl) propyl lactamide and other amine-containing groups Unsaturated monomers, vinyl sulfonic acid, phenylethane sulfonate, 2-(methyl) propyl hydrazine 2 - methyl propane sulfonic acid, 2 - (meth) propylene decyl ethane sulfonic acid and their A sulfonic acid monomer such as a salt. The polymerization method of the water-absorbent resin is not particularly limited, and a reverse phase suspension polymerization method or an aqueous solution polymerization method which is a production method can be used. The following is exemplified by a reverse phase suspension polymerization method. The s reverse phase suspension polymerization method can be carried out by using, for example, a polymerization initiator in the presence of a surfactant and a polymer protective colloid in a state in which an aqueous monomer solution is dispersed in an organic solvent. * The monomer concentration in the above aqueous monomer solution is preferably from 25% by weight to saturation. The aqueous monomer solution may be added at once in the polymerization reaction, and may be added in portions at 82963 1288026. The above organic A medium may be an alicyclic group such as n-pentyl, n-hexan, n-hung or petroleum bonds, etc. (3) aliphatic fe solvent, such as lyophile, methylcyclopentane, cyclohexane or methylcyclohexane. A hydrocarbon solvent or an aromatic hydrocarbon solvent such as benzene, toluene or xylene. Among them, n-pentane or cyclohexane is preferred. The amount of the organic solvent used is preferably from 50 to 600 parts by weight per 100 parts by weight of the total monomer, and from 100 to 5 50 parts by weight, from the viewpoint of easily removing the heat of polymerization and controlling the polymerization temperature. Better. The above surfactants are, for example, fatty acid sorbitan esters, mono-fatty acid glycerides, poly-fatty acid glycerides, fatty acid sucrose esters, polyoxyethylated hardened castor oil, lauric acid polyoxyethylated hardened castor oil, (3) Non-ionic surfactants such as isostearic acid polyoxyethylene hardened castor oil, polyoxyethyl sulfonyl phenyl ether, polyoxyethylene oxime lauryl ether, and polyoxyethylene hexyl decyl ether. The above-mentioned oxime molecular protective colloids are, for example, ethyl cellulose, light ethyl cellulose, oxidized polyethylene, maleic anhydride polyethylene, maleic anhydride polybutadiene and maleic acid fiber. ethylene-propylene-diene Ternary copolymers, etc. These nonionic surfactants and polymer protective colloids may also be used in combination of two or more. These nonionic surfactants and/or polymeric protective colloids may also be used in combination with an anionic surfactant. Anionic surfactants, for example, fatty acid salts, alkyl benzene sulfonates, alkyl methyl taurates, polyoxyethylene alkyl phenyl ether sulfates, and polyoxyethylene bromo ether salt . The amount of surfactant and/or polymeric protective colloid used is from the economic point of view that the aqueous monomer solution is sufficiently dispersed and the effect is proportional to the amount used. 82963 -11-1288026 per 100 parts by weight of the total amount of monomers, with 0 gt. 1 to 5 parts by weight is more preferable, and more preferably 2 to 3 parts by weight. The water-absorbent resin may be synthesized by a self-crosslinking type reaction without using a crosslinking agent, but may be crosslinked by using an internal crosslinking agent having two or more polymerizable unsaturated groups or one or more reactive groups. Internal cross-linking ^ for example, N, N'-methylene hydrazine (methyl) propionamide, ethylene glycol di(methyl) propionate, diethylene glycol bis(decyl) acrylate, two (methyl) diethylene glycol propyl phthalate, trimethylol propyl di(methyl) acrylate, trimethylol propyl tris (meth) acrylate, tris (hydroxymethyl propyl acrylate) a compound having two or more ethylenically unsaturated groups in one molecule, such as di(methyl)-propyl ether or triallylamine, or (poly)ethylene glycol diglycidyl ether and glycerol tricondensate A polyglycidyl ether such as glycerin ether or a self-generation epoxy compound such as epichlorohydrin or epibromohydrin. In view of the reactivity and water solubility in the polymerization system, one or two or more kinds thereof may be used. However, it is preferred to use a compound having two or more glycidyl groups in one molecule as an internal crosslinking agent. . The amount of the internal crosslinking agent used is from the viewpoint of moderately crosslinking the obtained water-absorbent resin to suppress water-soluble properties and exhibit sufficient water absorption, and the total amount of the above monomers is used per 10,000 parts by weight to use 〇·001 It is preferably from 3 parts by weight, more preferably from 0.003 to 1 part by weight, particularly preferably from 0.005 to 5 parts by weight. The polymerization initiator 'for example, may be potassium persulfate, sodium persulfate, ammonium persulfate, peroxydecanoate, hydrogen peroxide, 1,1,-arsenazo (cyclohexan-indene-nitrile), 2, 2 , _ arsenazo (2-methyl-butyronitrile), 2,2'-azobisisobutyronitrile, 2,2,-arsenazo (2-mercaptopropene) dihydrochloride, 2_ A radical polymerization initiator such as cyano-2-propylazocarbamide and 2,2,-arsenazo (2-methyl-propionic acid) dimethyl ester. These free radicals 82963 -12- 1288026 The polymerization initiator can also be used in combination with sulfite and the like as a redox polymerization initiator. The amount of the polymerization initiator to be used is preferably from 0.005 to 1 mol per kg of the total amount of the monomers per unit of the monomer from the viewpoint of shortening the polymerization reaction time and preventing the violent polymerization reaction to make the reaction easy to control. . The surfactant and/or the polymer protective colloid are dissolved in an organic solvent, and the aqueous monomer solution, polymerization initiator or the like is added thereto, and the mixture is heated under stirring to carry out reverse phase suspension polymerization in a water/oil system. The reaction temperature of the above polymerization reaction varies depending on the polymerization initiator to be used and the type of the monomer or the aqueous monomer solution. However, the polymerization proceeds rapidly, the polymerization time is shortened, the economical profit is satisfied, the heat of polymerization is easily removed, and the reaction is smooth. From the viewpoint of viewpoint, it is preferable to use °C, and it is more preferable to use cd Μ (10) 40 of 40 to 80A. Reaction time, usually 5 to 4 hours. The obtained water-absorbent resin, and I ^__ 八 & 斫 can be combined with a crosslinking agent containing two or more reactive oxo groups, and the surface is extended. As the surface crosslinking agent, it is possible to use a compound which can react with the hydrazine in the water-absorbent resin. For example, alcohol diglycidyl ether, (poly) _ _, V yong - ^) propanol% diglycidyl ether, (glycidyl linkages and sugar alcohols, etc. epoxide production of diprostol, epibromohydrin And α-methodamine alcohol temple halogenated epoxy compound, 1 soil surface ^ (to) ethylene glycol, (poly) propylene glycol, d) glycerol, glycols, pentanediol, - (per) glycanamine and = hexanediol such as ethanolamine, trimethylolpropane, diacetyl hydrazine, and polyvalent alcoholated octahydrate. These surfaces are used in conjunction with epoxidation. The surface of the temple can be used alone or in combination with two or more surface X-linking agents. The water-absorbent resin absorbs water at a gel strength and 82963 -13-1288026 to maintain the water absorption. The total amount of the above monomers is preferably 0.01 to 5 parts by weight, more preferably 0. 02 to 4 parts by weight, particularly preferably 0. 03 to 3 parts by weight. The method of adding the surface crosslinking agent is not particularly limited, and may be, for example, a method of adding it to a water-absorbent resin dispersed in an organic solvent, or a spraying method such as spraying while stirring the water-absorbent resin. The period of addition of the surface crosslinking agent may be a stage of hydrogel after polymerization, a stage of granules in drying, and a stage after drying. Among them, a method of adding to a water-absorbent resin dispersed in an organic solvent at the stage of a hydrogel after polymerization, and a method of spraying by spraying or the like in a stage of drying the aqueous particles are preferred. The addition form of the surface crosslinking agent is not particularly limited. However, it is preferred to add the surface crosslinking agent to the water-absorbent resin uniformly, and to dissolve the surface crosslinking agent in a hydrophilic solvent such as water. Hereinafter, the present invention will be described in detail by way of examples and comparative examples. However, the invention is not limited to the examples. Example 1 500 ml of n-heptane was added to a 1000 ml volume five-cylinder round bottom flask equipped with a stirrer, a reflux condenser, a dropping funnel, a thermometer, and a nitrogen introduction tube. To which is added decaglyceryl pentyl stearate having a Hlb of 5.0 (surfactant: Suns 〇 ft Q-185S, manufactured by Taiko Chemical Co., Ltd.) 1 · 38 g 'dissolve' the temperature and dissolve the surfactant, Cool to 55 〇C. In addition to the above, 92 g of an aqueous solution of a propionic acid solution of 8 wt% of 82963 -14 - 1288026 was added to a 500 ml volumetric flask. This was externally cooled while 102.2 g of a 30% by weight aqueous sodium hydroxide solution was added dropwise to neutralize 75 mol% of acrylic acid to prepare a partial neutralizer of acrylic acid. Then, 50.2 g of water, 0. 11 g of potassium persulfate as a polymerization initiator, and 18.4 mg of ethylene glycol diglycidyl ether as a crosslinking agent were added to prepare an aqueous monomer solution for polymerization. The polymerization was carried out in the above-mentioned five-neck 0-neck round bottom flask with the original water drop solution under the disturbance and dispersed, and the system was sufficiently replaced with nitrogen, and then the temperature was maintained at 70 ° C. The polymerization was carried out for 1 hour. After the completion of the polymerization, 66 g of a 14% by weight aqueous solution of trans-1,2-diaminocyclohexyltetraacetic acid tetrasodium chloride as an aminocarboxylic acid-based metal chelating agent was added under stirring. Then, by dehydration by co-freezing and removing water from the aqueous gel, it was moved outside the system. To the obtained gelatinous substance, 4.14 g of a 2% by weight aqueous solution of ethylene glycol diglycidyl ether was added, and water and n-heptane were removed by distillation and dried to obtain 93.0 g of a water-absorbent resin. Example 2 500 ml of n-heptane was added to a 1000 ml volume five-cylinder round bottom flask equipped with a stirrer, a reflux condenser, a dropping funnel, a thermometer and a nitrogen introduction tube. 92 g of a fatty acid sucrose ester (manufacturer, manufactured by Mitsubishi Chemical Corporation, S-37®) having an HLB of 3 Å was added thereto, and dispersed, heated, and the surfactant was dissolved, and then cooled to 5 51. In addition to the above, 92 g of a 8% by weight aqueous solution of propionic acid was added to a 500 ml volumetric flask. This was externally cooled, and 102.2 g of a 3 wt% aqueous solution of sodium cerium oxide was added dropwise to neutralize 75 mol% of acrylic acid to prepare a partial neutralizer of acrylic acid. Then, adding 5〇2§ of water, adding 82963 -15-1288026 to the initiator, potassium persulfate 0·1 lg, ethylene glycol diglycidyl 9.2 mg as a crosslinking agent, and preparing the first stage polymerization. Aqueous monomer solution. The aqueous solution of the first-stage polymerization monomer was added to the above-mentioned five-port cylindrical round bottom flask with agitation and dispersed, and the system was sufficiently substituted with nitrogen gas to be heated, and the bath temperature was maintained at 70 ° C. After the polymerization reaction was carried out for a while, the polymerization slurry was cooled to room temperature. Then, in a 500 ml volumetric flask, 8% by weight of propylene carbonate aqueous solution 119· lg was added, and while cooling, 30% by weight of aqueous sodium hydroxide solution 1 3 2 · 2 g was added dropwise to obtain acrylic acid. Neutralize with 7 5 mol%, then add 27.4 g of water, potassium persulfate 〇.l4g, ethylene glycol diglycidyl ether 35 7 mg, and prepare a monomer aqueous solution for one-stage polymerization in a week. Internal cooling. The aqueous solution of the second-stage polymerization monomer was added to the above-mentioned polymerization slurry in a total amount, and then the system was sufficiently replaced with nitrogen gas, and then the temperature was raised to 70 ° C, and the second-stage polymerization reaction was carried out for 2 hours. After the end of the polymerization, in an aqueous gelatinous substance dispersed in n-heptane, 40% by weight of an aqueous solution of an amine-based tetacid-based metal chelating agent is added to an aqueous solution of diethyltriamine pentaacetate. 3 g. Then, by azeotropic dehydration and removal of moisture from the aqueous gel, it is moved outside the system. To the obtained gelatinous substance, 8.44 g of a 2% by weight aqueous solution of ethylene glycol diglycidyl ether was added, and water and n-heptane were removed by distillation and dried to obtain 214.8 g of a water-absorbent resin. Example 3 Adding a Hg to a 500-volume five-cylinder round bottom flask equipped with a stirrer, a reflux condenser, a dropping funnel, a thermometer, and a nitrogen introduction tube, adding HLB to 3 _0 Fatty acid sucrose ester (interface activity 82963 -16-1288026 agent, manufactured by Mitsubishi Chemical Corporation, s_37〇) 〇92g, dispersed, heated and dissolved in the surfactant, and then cooled to 55. In addition to the above, 92 g of an aqueous solution of 8 wt% of acrylic acid was added to a 500 ml volumetric flask. This was externally cooled, while 3 liters of an aqueous solution of cerium oxide in an amount of 2.2 g was added dropwise to neutralize 75 mol% of propionic acid to prepare a partial neutralizer of acrylic acid. Then, water was added in an amount of 5.2 g, and potassium thioglycidyl ether (9.2 g) which is a crosslinking agent, and 9.2 mg of ethylene glycol diglycidyl ether as a crosslinking agent were added to prepare an aqueous monomer solution for polymerization. The polymerization monomer aqueous solution was added to the above-mentioned five-port cylindrical round bottom flask with stirring, and dispersed, and the system was sufficiently substituted with nitrogen gas to be heated, and the temperature was maintained at 7 ° C to carry out polymerization. 1 hour. After the end of the polymerization, the water was removed from the aqueous gel by azeotropic dehydration and moved to the outside of the system. To the obtained gelatinous substance, 4.14 g of a 2% by weight aqueous solution of ethylene glycol diglycidyl acid was added, and then water and n-heptane were removed by distillation, and then added as an aminocarboxylic acid-based metal under stirring. The powder of the chelating agent was triethylammonium hexaacetic acid (87% by weight of the entire particles was 1 〇〇μχη or less) of 0.46 g. Further, it was dried to remove water and n-heptane to obtain 92.8 g of a water-absorbent resin. (Example 4) In the same manner as in Example 3 except that triethylethylenetetraamine hexaacetic acid was not added, 92.0 g of a water-absorbent resin was obtained. Adding the total amount of the above-mentioned water-absorbent resin and the powder of di-ethyltriamine pentanoic acid disodium (85% by weight of the entire particle diameter of 100 μm or less) to 46 g and fully mixing in a polyacetonitrile bag. Water-absorbent resin 92 5 g. Example 5 82963 -17- 1288026 Add a n-gum-burning 500 m b to a 1000 ml volume five-cylinder round bottom flask equipped with a stirrer, a reflux condenser, a dropping funnel, a thermometer, and a nitrogen introduction tube. HLB is 4.7 sorbitan monostearate (surfactant: Nippon Oil Co., Ltd., N〇ni〇n SP_60R) 0 · 9 2 g 'Disperse, heat up and dissolve the surfactant, Cool to π °C. In addition to the above, in an Erlenmeyer flask having a volume of 500 ml, 92 g of an aqueous solution of acrylic acid having a weight of 0 Torr was added. This was cooled from the outside while a 3 wt% aqueous solution of sodium hydroxide (102. 2 g) was dropped to neutralize 75 mol% of acrylic acid, and a partial neutralizer of acrylic acid was obtained by hydrazine. Further, water 2〇 8§, 0.11 g of potassium persulfate which is a polymerization initiator, and N,N,_methylene propylene decylamine 23.0 mg which is a crosslinking agent are added. Further, 23 g of an aqueous solution of 4% by weight of di-ethyltriamine pentaacetic acid pentasodium carbonate as an aminocarboxylic acid-based metal chelating agent was added thereto to prepare an aqueous monomer solution for polymerization. The aqueous solution of the hydrazine polymerization monomer was added to the above-mentioned five-port cylindrical round bottom flask with stirring and dispersed, and the system was sufficiently replaced with nitrogen gas, and then the temperature was raised to maintain the bath temperature at 70 C for 2 hours. . After the end of the polymerization, the water was removed from the aqueous gel by azeotropic dehydration and moved to the outside of the system. To the obtained gelatinous substance, 2% by weight of ethylene glycol diglycidyl ether water/glutany solution 4 to 60 g was added, and water and n-heptane were removed by distillation and dried to obtain 93.8 g of a water-absorbent resin. Example 6: Adding n-gump 82963 -18- 1288026 alkane 550 m in a five-cylinder round bottom flask equipped with a (four) machine, a reflux cooler, a dropping funnel, a thermometer, and a nitrogen introduction tube < 1500 ml volume 0.84 g of sorbitan monolaurate (surfactant: N〇ni〇n Lp_2〇R) having an HLB of 8·6 was added thereto to disperse, heat up, and act as a surfactant. After dissolving, cool to shame. [. In addition to the above, 70 g of an aqueous solution of 8 wt% of hydrazine was added to a 500 ml volumetric flask. This was externally cooled while dropwise dropping 77.8 g of a 3 wt% sodium hydroxide aqueous solution to neutralize 75 mol% of propionic acid to prepare a partial neutralizer of acrylic acid. Then, 33 g of water and 84 g of potassium persulfate as a polymerization initiator were added to prepare an aqueous monomer solution for polymerization. The monomer aqueous solution for polymerization was added to the above-mentioned five-port cylindrical round bottom flask with stirring, and dispersed, and the system was sufficiently substituted with nitrogen gas, and then the temperature was raised, and the temperature was maintained at 7 ° C to carry out polymerization. 3 hours. After the end of the polymerization, in an aqueous gel, an aminocarboxylic acid-based metal chelate is added to the 40-fold hydrazine/hydrazine of Ethyldiamine pentanoic acid in an aqueous gel. The water is removed from the aqueous gel by azeotropic dehydration and moved outside the system. To the obtained gel, 3.15 g of a 2% by weight aqueous solution of ethylene glycol diglycidyl ether was added, and water and n-heptane were removed by distillation and dried to obtain a water-absorbent resin of 74. g. Example 7 The same operation as in Example 5 was carried out except that 1.21 g of a 38% by weight aqueous solution of ethyldiaminetetraacetic acid tetrasodium acetate was added instead of one of the ethylamine triamine pentanoic acid #9 in Example 5. Water-absorbent resin 93 · 6g. Comparative Example 1 In the same manner as in Example 1, except that the aminocarboxylic acid-based metal chelating agent in the Example 不 was not added, 92.1 g of a water-absorbent resin was obtained. 82963 -19- 1288026 Comparative Example 2 The same procedure as in Example 2 was carried out, except that the aminocarboxylic acid-based metal chelating agent of Example 2 was not added, to obtain 2.5 g of a water-absorbent resin. Comparative Example 3 A water-absorbent resin of 92·1 g was obtained in the same manner as in Example 3 except that the aminocarboxylic acid-based metal chelating agent of Example 3 was not added. Comparative Example 4 The same operation as in Example i was carried out except that 92 g of citric acid citrate was added in an amount of 9.2 g of an aqueous solution of water in place of the trans-1,2-diaminocyclohexyltetraacetic acid tetrasodium salt of Example 1. A water-absorbent resin of 92·8 g was obtained. Comparative Example 5 The same operation as in Example 3 was carried out except that 0.46 g of sodium tripolyphosphate (90% by weight of the entire particles was 1 〇〇pm or less) was added instead of the triethylhexylamine hexaacetic acid in Example 3. The water-absorbent resin was obtained in an amount of 92.6 g. The coloring test of the water-absorbent resin obtained in the above examples and comparative examples was carried out by the following method. [Coloring test of water-absorbent resin] 2.0 g of a water-absorbent resin was uniformly added to a polypropylene-made container having an inner diameter of 3 cm and a depth of 1 cm. The container was placed in a tabletop constant temperature and humidity chamber set to a temperature of 5 〇 ± 2 ° C and a relative humidity of 90 ± 2% RH for 2 days. After placing, remove the container from the strange temperature calendar, briefly place it and then cool to room temperature. In a glass measuring container with an inner diameter of 3 cm, the total amount of the water-absorbent resin in the container is added, and the color measurement of the color difference meter is performed by a standard whiteboard, and the correction of the three sensing values ¥, ¥, and 2 is performed, and the two-beam irradiation photometry is used. The color difference meter of the method 1 (9) 1 dp 82963 -20 - 1288026 (manufactured by Nippon Denshoku Industries Co., Ltd.) measures the yellowness of the water-absorbent resin. From the X, Y and Z (three-induction values) of the obtained water-absorbent resin, the yellowness was calculated by the following formula. Similarly, the yellowness of the water-absorbent resin before the test was placed in a desktop constant temperature and humidity chamber for 20 days. Further, the above measurement was carried out three times, and the average value thereof was used. Yellowness = 100 (1·28 Χ -1·06 Ζ) / 著 The coloring test results of the aminocarboxylic acid-based metal chelating agent used in the above examples and the water-absorbent resins obtained in the above Examples and Comparative Examples are shown in Table 1. Shown. Further, the amount in the brigade in Table 1 is an amount relative to 100 parts by weight of propionate. Table 1 Types of coloring test results of aminocarboxylic acid-based metal chelating agents (parts by weight) Difference in yellowness and yellowness after yellowness test before the test Example 1 Trans-1,2-diaminocyclohexyltetraacetic acid tetrasodium (0.126 9.5 12.6 3.1 Example 2 Pentaethylidene triamine pentaacetate pentasodium (0.125) 9.7 12.9 3.2 Example 3 Tris-ethyltetramine hexahydrous acid (0.625) 9.9 12.9 3.0 Example 4 Diethyltriamine Disodium pentaacetate (0.625) 10.1 13.1 3.0 Example 5 Disodium ethyltriamine pentaacetate pentasodium (0.125) 9.8 12.8 3.0 Example 6 Diethyltriamine pentaacetate pentasodium (0.125) 5.5 7.0 1.5 Example 7 Ethylenediamine tetraacetic acid tetrasodium (〇·625) 10.0 15.9 5.9 Comparative Example 1 (no addition) 10.8 21.9 11.1 Comparative Example 2 (no addition) 10.4 21.1 10.7 82963 -21 - 1288026 Comparative Example 3 (no addition) 10.2 21.5 11.3 Comparative Example 4 citric acid (1.25) 10.0 20.7 10.7 Comparative Example 5 Sodium tripolyphosphate (0.625) 9.9 20.0 10.1 From Table 1, the water absorption of the aminocarboxylic acid-based metal chelating agent obtained in the examples was known. The resin has little change in yellowness before and after the test, and coloring is suppressed. On the other hand, the water-absorbent resin obtained by the comparative example in which the aminocarboxylic acid-based metal chelating agent was not added had a large change in yellowness and a considerable degree of coloration. Industrial Applicability According to the present invention, by producing a water-absorbent resin in the presence of an aminocarboxylic acid-based chelating agent, the coloring of the water-absorbent resin is suppressed even under severe environmental conditions of high temperature and high humidity. As described above, it is apparent that the present invention may be embodied in a variety of forms within the scope of the same nature without departing from the spirit and scope of the invention, and all modifications apparent to those skilled in the art are included in the following claims. Within the scope of Fan Yuan's technology. 82963 -22-