JP2004052187A

JP2004052187A - Hygroscopic underwear

Info

Publication number: JP2004052187A
Application number: JP2002214693A
Authority: JP
Inventors: Minoru Mizobe; 溝部　穣; Shigeru Nakajima; 中島　　茂
Original assignee: Japan Exlan Co Ltd
Current assignee: Japan Exlan Co Ltd
Priority date: 2002-07-24
Filing date: 2002-07-24
Publication date: 2004-02-19

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hygroscopic underwear through using at least on part a fiber for solving a defect as color instability which a conventional hygroscopic fiber holds while maintaining characteristics required as a hygroscopic fiber. <P>SOLUTION: The hygroscopic underwear comprises a high whiteness hygroscopic synthetic fiber having saturation moisture absorption of ≥10 wt.% at 20°C 65% RH, whiteness of L*85 and more and a*±6 in a notation in Japanese Industrial Standards-Z-8729, and discoloration of 3-4 grade and more after five times washing process by Japanese Industrial Standards-L0217-103 method, evaluated by gray scale for Japanese Industrial Standards-L0805 contamination. The high whiteness underwear has hygroscopic property to prevent stuffy feeling and stickiness when wearing and excellent aesthetic property. Furthermore, the hygroscopic underwear of clear color, especially light color is also provided. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は吸湿性肌着に関する。さらに詳しくは、吸放湿性を有し、さらに加工性も優れ、かつ従来品よりもさらに白度が向上し染色工程での晒し処理および洗濯を繰り返しても色がほとんど変化しない色安定性に優れる高白度吸湿性合成繊維を少なくとも一部に用いた吸湿性肌着に関する。
【０００２】
【従来の技術】
着用時のムレ感、べたつき等の不快感を防ぐため、肌着の一部に吸湿性繊維を用いることが行われている。かかる吸湿性繊維として、潮解性塩類を高吸水性繊維に含浸させた特開平１−２９９６２４号公報の手段が提案されている。この手段により得られた繊維は、編物・織物・不織布等への加工が容易で吸放湿速度が速く、さらに吸湿剤の脱落もない実用性能を備えたものではあるが、繊維表面がヒドロゲルであるため、吸湿すると粘着性を帯び、直接肌に触れる肌着への適用が困難であること、及び最近社会的ニーズとして高まりつつある難燃性や抗菌性を満たすものではなかった。
【０００３】
これらの問題点を解決する方法として、特開平５−１３２８５８号公報の手段も提案されている。しかしながら、この方法では塩型カルボキシル基の量が４．５ｍｅｑ／ｇを超えてしまうと引張強度が０．９ｃＮ／ｄｔｅｘ以下となり、種々の加工に耐え得るには不十分な繊維物性となってしまい、さらに吸湿率を高める為の障壁となっていた。また、繊維強度０．９ｃＮ／ｄｔｅｘ以上の高吸湿性繊維を得る為にヒドラジン系化合物による処理によって導入される窒素含有量の増加を８．０重量％をこえたものにした場合、加水分解後の塩型カルボキシル基の導入量が少なくなり、吸湿性が低くなってしまうという問題があった。
【０００４】
さらに、特開平５−１３２８５８号公報による方法で得られる繊維は、濃いピンク色から濃い茶色を呈する為、利用分野が限定されてしまうという欠点があった。この欠点を克服する手段として提案されている特開平９−１５８０４０号公報の発明は、ヒドラジン系化合物による架橋処理の後に酸処理Ａを行うこと、アルカリによる加水分解処理の後に酸処理Ｂを行うこと、を開示し相当に白度の改善を為し得ている。それでもなお、淡桃色〜淡褐色に着色しており、かかる吸湿性繊維を用いた肌着は、該繊維の色相をそのまま保持するため、白色の肌着には不向きであり、また、色物であっても、該繊維の色相のため、くすんだ色となってしまい、鮮明な色が得られず、特に淡色の肌着には不向きであった。特開２０００−３０３３５３号公報では白度を改善する方法として加水分解処理を無酸素雰囲気下で行うことを開示している。しかしながら、これらの方法で得られる繊維は染色工程での酸化晒し処理や洗濯を繰り返すことにより着色し、色安定性に乏しいという欠点を有するため、審美性や清潔感を要求される肌着分野に対しては、十分満足を与えるものではないのが現状である。
【０００５】
【発明が解決しようとする課題】
本発明は、繊維に要求される基本物性並びに吸湿性繊維の有すべき特性を維持しながら、かかる従来の吸湿性繊維が抱える色が不安定であるという欠点を改良した高白度吸湿性合成繊維を少なくとも一部に用いた吸湿性肌着を提供することを目的とする。
【０００６】
【課題を解決するための手段】
上述した本発明の目的は、２０℃６５％ＲＨにおける飽和吸湿率が１０重量％以上である吸湿性合成繊維であって、該繊維の白度がＪＩＳ−Ｚ−８７２９に記載の表示方法において、Ｌ＊８５以上、ａ＊±６（以下、Ｌ＊及びａ＊は、ＪＩＳ−Ｚ−８７２９に記載の表示方法に従ったものである）の範囲内であり、且つＪＩＳ−Ｌ０２１７−１０３法（洗剤は花王株式会社製アタック使用）で洗濯処理した洗濯５回後の繊維の変色がＪＩＳ−Ｌ０８０５汚染用グレースケールで評価して３−４級以上である高白度吸湿性合成繊維を少なくとも一部に用いた吸湿性肌着により達成することが出来る。
【０００７】
さらに本発明の目的は、吸湿性肌着に用いる高白度吸湿性合成繊維の飽和吸水率が３００重量％未満、好ましくは２００重量％以下、より好ましくは１５０重量％以下であること、高白度吸湿性合成繊維が共重合成分として（メタ）アクリル酸エステル化合物が５重量％未満であるアクリロニトリル系重合体からなるアクリル系繊維に、ヒドラジン系化合物による架橋導入処理、加水分解、還元処理を施したものであること、洗濯５回後の該繊維の白度が、Ｌ＊８５以上、ａ＊±６の範囲内であることにより、好適に達成することができる。
【０００８】
また、かかる高白度吸湿性合成繊維を少なくとも一部に用いた肌着の、ＪＩＳ−Ｌ−０２１７−１０３法で洗濯処理した洗濯５回後の肌着の変色がＪＩＳ−Ｌ−０８０５汚染用グレースケールで評価して３−４級以上であることにより達成される。
【０００９】
【発明の実施の形態】
以下、本発明を詳述する。本発明に用いる高白度吸湿性合成繊維は２０℃６５％ＲＨにおける飽和吸湿率が１０重量％以上の吸湿性合成繊維である必要がある。さらに好ましくは１５重量％であり、吸湿状態でべたつき感が無い限り上限を限定する必要はないが、実質的には爽やか感を維持したまま１００重量％を超えるのは至難である。なお１０重量％未満では、ムレ感等の不快感を防ぐことはできないため採用できない。さらに、該繊維の白度は、Ｌ＊８５以上、ａ＊±６の範囲内である必要がある。Ｌ＊が８５未満、ａ＊が±６の範囲外である場合には、もはや白度に優れているとはいえない。なお、好ましくはＬ＊が８６以上、ａ＊が±４の範囲内である。
【００１０】
また、本発明の吸湿性肌着の少なくとも一部に用いる高白度吸湿性合成繊維は、洗濯処理においても、その白度の変色が極めて少ない点、即ち洗濯耐久性に優れている点に特徴があり、具体的には、ＪＩＳ−Ｌ０２１７−１０３法（洗剤は花王株式会社製アタック使用）で洗濯処理した洗濯５回後の繊維の変色がＪＩＳ−Ｌ０８０５汚染用グレースケールで評価して３−４級以上のものである。なお、洗濯処理後であっても、繊維の白度が、Ｌ＊８５以上、ａ＊±６の範囲内、好ましくはＬ＊が８６以上、ａ＊が±５の範囲内であることが望ましい。また洗濯処理による白度の変色は赤みへの変化であり、赤みを表すパラメーターであるａ＊の値の、洗濯前後における差（Δａ＊）が０．７以下、好ましくは０．６以下であることが望ましい。
【００１１】
また、本発明の吸湿性肌着の少なくとも一部に用いる高白度吸湿性合成繊維の飽和吸水率は、３００重量％未満であることが好ましい。飽和吸水率が、３００重量％以上の場合には、吸水した際繊維表面がべとつくため肌着用途では好ましくない。
【００１２】
なお、高白度吸湿性合成繊維としては、染色工程の酸化晒し等の処理においても、その白色度が低下しないことが望ましく、具体的には、過酸化水素濃度０．５重量％、ＮａＯＨによるｐＨ１０、浴比１／５０、８０℃、６０分の条件で晒し処理した過酸化水素晒し後の繊維の変色（晒し耐久性）がＪＩＳ−Ｌ０８０５汚染用グレースケールで評価して３級以上、繊維を飽和吸水量を超える水の共存下８０℃１６時間放置した後の変色（放置安定性）がＪＩＳ−Ｌ０８０５汚染用グレースケールで評価して３−４級以上であることが好ましい。
【００１３】
ここで、晒し耐久性の値（級）は、ＮａＯＨによりｐＨ１０に調節した過酸化水素０．５重量％の水溶液中に、繊維試料と水溶液の浴比が１／５０となるよう繊維試料を投入し、８０℃で、６０分間晒し処理した繊維の、晒し処理前の繊維試料の色からの変色の程度をＪＩＳ−Ｌ０８０５汚染用グレースケールで評価することによって得られたものである。
【００１４】
また、放置安定性の値（級）は試料繊維を純水に浸漬し、十分含水させた後取出し、８０℃においても飽和吸水量を超える水が維持できるに十分な量の水を保持させたまま、容器の半分以上が空間となるよう容器に密閉して、８０℃に調整した恒温機に入れ、１６時間後取出し、脱水、乾燥した繊維の、処理前の繊維試料からの変色の程度をＪＩＳ−Ｌ０８０５汚染用グレースケールで評価することによって得られたものである。
なお、飽和吸水量とは、十分含水した繊維の遠心脱水後（１６０Ｇ×５分間）の重量から、同じ試料繊維の乾燥（１０５℃×１６時間）後の重量を引いた量である。また、飽和吸水率は、飽和吸水量を試料繊維の乾燥（１０５℃×１６時間）後の重量で除した値を％で表したものである。
【００１５】
本発明の吸湿性肌着は、かかる高白度吸湿性合成繊維を少なくともその一部に用いた肌着であり、該高白度吸湿性合成繊維のみからなるものであっても、木綿、羊毛、ポリエステル繊維、アクリル繊維等の他の繊維と混用したものであっても構わない。また、他の繊維と混用する場合において、他の繊維の種類や混合割合は、特に限定されるものではなく、各肌着に必要とされる特性に応じて適宜選択すればよい。なお、高白度吸湿性合成繊維の混用形態としては紡績における混綿及び精紡・撚糸工程での交撚、布帛作製での通常交編及び２〜３層交編等が例示されるが、これらに限定されるものではない。
【００１６】
本発明の吸湿性肌着の製造方法としては、上記高白度吸湿性合成繊維を少なくともその一部に用いる限り特に限定されるものではなく、通常の方法が採用できる。例えば、高白度吸湿性合成繊維と他の繊維とを混紡して紡績糸となし、織編物を製造し、かかる織編物を裁断、縫製して吸湿性肌着を製造する方法、あるいは、高白度吸湿性合成繊維と他の繊維を交編、交織して織編物を製造し、かかる織編物を裁断、縫製して吸湿性肌着を製造する方法が挙げられる。なお、本発明の吸湿性肌着においては、上記織編物単独で肌着を製造しても構わないし、上記織編物を肌着の一部に使用しても構わない。
【００１７】
本発明の吸湿性肌着は、上記高白度吸湿性合成繊維を少なくともその一部に用いているため、優れた審美性を有する高白度の吸湿性肌着を得ることができ、さらに鮮明な色、特に鮮明な淡色の吸湿性肌着をも得ることができる。例えば、高白度の肌着であれば、白度の優れた繊維と混用することにより、あるいはその他の繊維と混紡し紡績糸、編織物とした後、晒し、漂白等の処理により白度を向上させることによって、上記高白度吸湿性合成繊維以上の白度を有する肌着とすることができる。
また、鮮明な色、特に鮮明な淡色の肌着であれば、上記高白度吸湿性合成繊維以外の繊維を通常の方法により染色することによって得ることができる。
【００１８】
かかる肌着は、従来の淡桃色〜淡褐色に着色した吸湿性合成繊維の色相の影響を受けることなく、審美性、清潔感に優れたものである。なお、本発明の肌着においては、ＪＩＳ−Ｌ−０２１７−１０３法で洗濯処理した洗濯５回後の肌着の変色がＪＩＳ−Ｌ−０８０５汚染用グレースケールで評価して３−４級以上であることが好ましい。従って、混用される上記高吸湿性合成繊維以外の繊維もかかる洗濯耐久性を有することが望ましい。
【００１９】
なお、本発明の吸湿性肌着としては、ガードル、ショーツ、ブラジャー、キャミソール、ペチコート、パンティーストッキング、ストッキング、タイツ、ランニングシャツ、靴下等の婦人用、紳士用、子供用肌着などが挙げられる。
【００２０】
なお、上述したように、本発明の吸湿性肌着において、高白度吸湿性合成繊維の量に限定はないが、肌着として該繊維の特徴が明確に発現するという意味で、５重量％以上、さらに好ましくは１０重量％以上、最も好ましくは１５重量％以上含有されるのがよい。一方高白度吸湿性合成繊維以外の繊維素材が残余を占めることは言うまでもないが、必ずしも１種の素材である必要はなく、２種以上の素材を混用することも当然行ない得る。
【００２１】
本発明の吸湿性肌着に採用する高白度吸湿性合成繊維の製造方法としては、共重合成分として（メタ）アクリル酸エステル化合物が５重量％未満であるアクリロニトリル系重合体からなるアクリル系繊維に、ヒドラジン系化合物による架橋導入処理、加水分解、還元処理を施すことを特徴とする高白度吸湿性合成繊維の製造方法が推奨される。以下該方法について詳述する。
【００２２】
出発アクリル系繊維（以下、アクリロニトリル系繊維と呼ぶこともある）としてはアクリロニトリル（以下、ＡＮという）を４０重量％以上、好ましくは５０重量％以上含有するＡＮ系重合体により形成された繊維であり、短繊維、トウ、糸、編織物、不織布等いずれの形態のものでも良く、また、製造工程中途品、廃繊維などでも構わない。ＡＮ系重合体は、ＡＮ単独重合体、ＡＮと他の単量体との共重合体のいずれでも良いが、ＡＮと共重合する単量体として（メタ）アクリル酸エステル化合物は最も好ましくは使用を避けたいが、やむを得ず用いる場合は、５重量％未満さらに好ましくは４．０重量％以下である必要がある。尚、（メタ）を付した表記は、アクリル酸エステル，メタアクリル酸エステルの双方を表わしている。また、５重量％未満であれば共重合成分としてもかまわない該エステル化合物としては、例えば、（メタ）アクリル酸メチル、（メタ）アクリル酸エチル、（メタ）アクリル酸ブチル、（メタ）アクリル酸ジメチルアミノエチル、（メタ）アクリル酸ジエチルアミノエチル等が挙げられる。それ以外の共重合成分としてはメタリルスルホン酸、ｐ−スチレンスルホン酸等のスルホン酸基含有単量体及びその塩；スチレン、酢酸ビニル等の単量体等、ＡＮと共重合可能な単量体であれば特に限定されないが、酢酸ビニルに代表されるビニルエステル系化合物を５〜２０重量％共重合させることが望ましい。かかるビニルエステルとしては酢酸ビニル、プロピオン酸ビニル、酪酸ビニル等が挙げられる。
【００２３】
該アクリル系繊維は、ヒドラジン系化合物により架橋導入処理を施され、アクリル系繊維の溶剤では最早溶解されないものとなるという意味で架橋が形成され、同時に結果として窒素含有量の増加が起きるが、その手段は特に限定されるものではない。この処理による窒素含有量の増加が１．０〜１０重量％に調整し得る手段が好ましいが、窒素含有量の増加が０．１〜１．０重量％であっても、本発明で採用しうる高白度吸湿性合成繊維が得られる手段である限り採用し得る。なお、窒素含有量の増加を１．０〜１０重量％に調整し得る手段としては、ヒドラジン系化合物の濃度５〜６０重量％の水溶液中、温度５０〜１２０℃で５時間以内で処理する手段が工業的に好ましい。尚、窒素含有量の増加を低率に抑えるには、反応工学の教える処に従い、これらの条件をよりマイルドな方向にすればよい。ここで、窒素含有量の増加とは原料アクリル系繊維の窒素含有量とヒドラジン系化合物による架橋が導入されたアクリル系繊維の窒素含有量との差をいう。
【００２４】
ここに使用するヒドラジン系化合物としては、特に限定されるものでなく、水加ヒドラジン、硫酸ヒドラジン、塩酸ヒドラジン、臭素酸ヒドラジン、ヒドラジンカーボネート等、この他エチレンジアミン、硫酸グアニジン、塩酸グアニジン、リン酸グアニジン、メラミン等のアミノ基を複数含有する化合物が例示される。
【００２５】
かかるヒドラジン系化合物による架橋導入処理工程を経た繊維は、酸処理を施しても良い。この処理は、繊維の色安定性の向上に寄与がある。
ここに使用する酸としては、硝酸、硫酸、塩酸等の鉱酸の水溶液、有機酸等が挙げられるが特に限定されない。この処理の前に架橋導入処理で残留したヒドラジン系化合物は、十分に除去しておく。該酸処理の条件としては、特に限定されないが、大概酸濃度５〜２０重量％、好ましくは７〜１５重量％の水溶液に、温度５０〜１２０℃で０．５〜１０時間被処理繊維を浸漬するといった例が挙げられる。
【００２６】
ヒドラジン系化合物による架橋導入処理工程を経た繊維、或いはさらに酸処理を経た繊維は、続いてアルカリ性金属塩水溶液により加水分解される。この処理により、アクリル系繊維のヒドラジン系化合物処理による架橋導入処理に関与せずに残留しているＣＮ基、及び架橋処理工程後酸処理を施した場合には残留しているＣＮ基と一部酸処理で加水分解されたＣＯＮＨ_２基の加水分解が進められる。これらの基は加水分解によりカルボキシル基を形成するが、使用している薬剤がアルカリ性金属塩であるので、結局金属塩型カルボキシル基を生成している。ここで使用するアルカリ性金属塩としては、アルカリ金属水酸化物、アルカリ土類金属水酸化物、アルカリ金属炭酸塩等が挙げられる。使用するアルカリ性金属塩の濃度は特に限定されないが、１〜１０重量％さらに好ましくは１〜５重量％の水溶液中、温度５０〜１２０℃で１〜１０時間以内で処理する手段が工業的、繊維物性的にも好ましい。
【００２７】
ここで金属塩の種類即ちカルボキシル基の塩型としては、Ｌｉ，Ｎａ，Ｋ等のアルカリ金属、Ｍｇ，Ｃａ，Ｂａ等のアルカリ土類金属を挙げることが出来る。加水分解を進める程度即ち金属塩型カルボキシル基の生成量は４〜１０ｍｅｑ／ｇに制御すべきであり、これは上述した処理の際の薬剤の濃度や温度，処理時間の組合せで容易に行うことができる。尚、かかる加水分解工程を経た繊維は、ＣＮ基が残留していてもいなくてもよい。ＣＮ基が残留していれば、その反応性を利用して、さらなる機能を付与する可能性がある。
【００２８】
次いで行なわれる還元処理において使用する還元処理剤としてはハイドロサルファイト塩、チオ硫酸塩、亜硫酸塩、亜硝酸塩、二酸化チオ尿素、アスコルビン酸塩、ヒドラジン系化合物からなる群より選ばれた１種類または２種類以上を組み合わせた薬剤が好適に使用できる。該還元処理の条件としては、特に限定されないが、概ね薬剤濃度０．５〜５重量％の水溶液に、温度５０〜１２０℃で３０分間〜５時間被処理繊維を浸漬するといった例が挙げられる。なお、該還元処理は前述の加水分解時に同時に行ってもよいし、加水分解後に行なってもよい。
【００２９】
かくして、本発明の吸湿性肌着に用いる高白度吸湿性合成繊維が得られるが、より色を安定化させるため、前述の還元処理工程を経た繊維に、酸処理を施し、該金属塩型カルボキシル基をＨ型化し、Ｌｉ、Ｎａ、Ｋ、Ｃａ、Ｍｇ、Ｂａ、Ａｌから選ばれる金属塩処理により、該Ｈ型カルボキシル基の一部を金属塩型化（塩型調整処理）してＨ型／金属塩型のモル比を９０／１０〜０／１００に調整することが好ましい。
【００３０】
ここに酸処理に使用する酸としては、硝酸、硫酸、塩酸等の鉱酸の水溶液、有機酸等が挙げられるが特に限定されない。該酸処理の条件としては、特に限定されないが、大概酸濃度１〜１０重量％、好ましくは２〜１０重量％の水溶液に、温度５０〜１２０℃で２〜１０時間被処理繊維を浸漬するといった例が挙げられる。
【００３１】
また塩型調整処理に採用される金属塩の金属種類としては、Ｌｉ、Ｎａ、Ｋ、Ｃａ、Ｍｇ、Ｂａ、Ａｌから選ばれるが、Ｎａ、Ｋ、Ｃａ、Ｍｇ等が特に推奨される。又塩の種類としては、これらの金属の水溶性塩であれば良く、例えば水酸化物，ハロゲン化物，硝酸塩，硫酸塩，炭酸塩等が挙げられる。具体的には、夫々の金属で代表的なものとして、Ｎａ塩としてはＮａＯＨ、Ｎａ_２ＣＯ_３、Ｋ塩としてはＫＯＨ、Ｃａ塩としてはＣａ（ＯＨ）_２、Ｃａ（ＮＯ_３）_２、ＣａＣｌ_２が好適である。
【００３２】
カルボキシル基のＨ型／金属塩型モル比は上述した範囲内であるが、繊維に与えようとする機能により、金属の種類と共に適宜設定する。塩型調整処理の具体的な実施にあたっては、処理槽に金属塩の０．２〜３０重量％の水溶液を準備し、２０〜８０℃において０．２５〜５Ｈｒ程度被処理繊維を浸漬する、あるいは該水溶液を噴霧する等の方法がある。上述の比率に制御するには、緩衝剤共存下での塩型調整処理が好ましい。緩衝剤としてはｐＨ緩衝域が５．０〜９．２のものが好適である。また、金属塩型カルボキシル基の金属塩の種類は１種類に限定されるわけではなく、２種類以上が混在してもかまわない。
【００３３】
又、塩型調整処理をＣａ，Ｍｇ，Ｂａ等の金属塩化合物の如き水溶解度が低い物質で行う場合には、該工程においてＨ型カルボキシル基からＨ型／金属塩型のモル比を、金属塩型を高める方向にするのに幾分難がある。かかる場合には、酸処理の後で塩型調整処理の前処理として、酸処理工程においてＨ型化されているカルボキシル基を、苛性ソーダあるいは苛性カリ等の水溶液で該カルボキシル基の示すｐＨを調整即ち中和処理（ｐＨ＝５〜１１位）しておくことが推奨される。かかる処方により、中和処理後のカルボキシル基はＨ型とＮａ又はＫ型が共存する状態になっているので、次の塩型調整処理はＣａ等とＮａ又はＫとの交換となって容易に進行するので、提起した難点が解消する。
【００３４】
なお、出発原料であるアクリル系繊維の製造手段は特に限定されるものではなく、通常の衣料用繊維の製造に採用される手段を用いることができる。
また、このような繊維を出発繊維として用いる事が好ましいが、必ずしも最終工程まで済んでいる必要はなく、アクリル系繊維製造工程途中のものであっても、あるいは最終繊維に紡績加工等を施した後のものでも良い。中でも出発アクリル系繊維として、アクリル系繊維の製造工程途中である延伸後熱処理前の繊維（ＡＮ系重合体の紡糸原液を常法に従って紡糸し、延伸配向されてはいるが、乾燥緻密化、湿熱緩和処理等の熱処理の施されてない繊維、中でも湿式又は乾／湿式紡糸、延伸後の水膨潤ゲル状繊維：水膨潤度　３０〜１５０％）を使用すると、処理液中への繊維の分散性、繊維中への処理液の浸透性などが改善され、以て架橋結合の導入や加水分解反応が均一かつ速やかに行われるので望ましい。
【００３５】
なお、これらの出発アクリル系繊維を、攪拌機能、温度制御機能を備えた容器内に充填し、前述の工程を順次実施する、あるいは複数の容器を並べて連続的に実施する等の手段をとることが、装置上、安全性、均一処理性等の諸点から望ましい。かかる装置としては染色機が例示される。
【００３６】
本発明の肌着に用いる高白度吸湿性合成繊維を製造する他の方法としては、アクリル系繊維に、上述してきたヒドラジン系化合物による架橋導入処理、加水分解、還元処理、酸処理を施し、更に還元処理、酸処理を繰り返す方法が挙げられる。還元処理、酸処理を繰り返すことにより、白度及び色安定性が向上し、Ｌ＊８５以上、ａ＊±６の範囲内であり、且つ洗濯耐久性が３−４級以上という高白度吸湿性合成繊維が得られる。本方法によると、アクリル系繊維を形成するアクリロニトリル系重合体の共重合成分として、（メタ）アクリル酸エステル化合物が５重量％以上であっても、本発明の吸湿性肌着に採用しうる高白度吸湿性合成繊維を得ることが出来るが、還元処理、酸処理を繰り返すことが必要であることから、繊維物性が低下したり、生産コストが高くなったりするため、上述した本発明が推奨する製造方法を採用する方が有利である。
【００３７】
本発明の吸湿性肌着は上述した高白度吸湿性合成繊維を少なくともその一部に採用したものであり、吸湿性を有するため、着用時のムレ感やべたつきを防ぐことができ、さらに優れた審美性を有する高白度の吸湿性肌着、さらに鮮明な色、特に鮮明な淡色の吸湿性肌着をも提供することができる。
【００３８】
【作用】
以上詳述した、本発明の吸湿性肌着の少なくとも一部に採用する高白度吸湿性合成繊維が、優れた白度及び色安定性を有する理由は、十分解明するに至っていないが、概ね次のように考えられる。即ち、ヒドラジン系化合物により架橋構造を導入される際に、原料であるアクリル系繊維が共重合成分として（メタ）アクリル酸エステル化合物を５重量％以上含む場合は該共重合成分のカルボニル炭素の部分にヒドラジン系化合物が反応することにより結果的に架橋構造に酸素分子を含む結合が導入され発色しやすく、即ち色安定性が劣ることとなるが、本発明が推奨する製造方法では該結合の生成を原料段階で抑制したために発色が抑えられ、過酸化水素晒し処理や洗濯繰り返し等の処理によっても発色しにくいと推定される。また、（メタ）アクリル酸エステル化合物を５重量％以上含む場合であっても、還元処理、酸処理を繰り返すことにより、過酸化水素晒し処理や洗濯繰り返し等の処理によっても、発色する分子構造に変化しにくい安定した分子構造を持つためであると推定される。
【００３９】
【実施例】
以下実施例により本発明を具体的に説明する。実施例中の部及び百分率は、断りのない限り重量基準で示す。なお、金属塩型カルボキシル基量、白度および飽和吸湿率等は以下の方法により求めた。また、実施例中の洗濯は、ＪＩＳ−Ｌ０２１７−１０３法（洗剤は花王株式会社製アタック使用）に従って行い、これを５回繰り返した。
【００４０】
（１）金属塩型カルボキシル基量（ｍｅｑ／ｇ）
十分乾燥した試料繊維約１ｇを精秤し（Ｘｇ）、これに２００ｍｌの水を加えた後、５０℃に加温しながら１ｍｏｌ／ｌ塩酸水溶液を添加してｐＨ２にし、次いで、０．１ｍｏｌ／ｌＮａＯＨ水溶液で常法に従って滴定曲線を求めた。該滴定曲線からカルボキシル基に消費されたＮａＯＨ水溶液消費量（Ｙｍｌ）を求め、次式によってカルボキシル基量（ｍｅｑ／ｇ）を算出した。
（カルボキシル基量）＝０．１Ｙ／Ｘ
別途、上述のカルボキシル基量測定操作中の１ｍｏｌ／ｌ塩酸水溶液の添加によるｐＨ２への調整をすることなく同様に滴定曲線を求めＨ型カルボキシル基量（ｍｅｑ／ｇ）を求めた。これらの結果から次式により金属塩型カルボキシル基量を算出した。
（金属塩型カルボキシル基量）＝（カルボキシル基量）−（Ｈ型カルボキシル基量）
【００４１】
（２）繊維の白度
カード機にて開繊した試料繊維４．０ｇを回転式測色セル（３５ｍｌの透明円筒セル）に充填し、東京電色社製色差計ＴＣ−１５００ＭＣ−８８型（Ｄ６５光源）にて、６０回／分の割合で回転させながら測色した。この測定を３回繰り返し、Ｌ＊、ａ＊の値（平均値）を求めた。
（３）飽和吸湿率（％）
試料繊維約５．０ｇを熱風乾燥機で１０５℃、１６時間乾燥して重量を測定する（Ｗ１ｇ）。次に試料を温度２０℃で６５％ＲＨの恒温槽に２４時間入れておく。このようにして吸湿した試料の重量を測定する（Ｗ２ｇ）。以上の測定結果から、次式によって算出した。
（吸湿率　％）＝｛（Ｗ２−Ｗ１）／Ｗ１｝×１００
（４）飽和吸水率（％）
試料繊維を純水に十分浸漬し、含水させた後取り出し遠心脱水後（１６０Ｇ×５分間）の重量から同じ試料繊維の乾燥（１０５℃×１６時間）後の重量を差し引いて得られる吸水量を、左記乾燥後重量で除した値を％で表したものである。
（５）肌着の白度
肌着の一部をマクベス社製色差計（Ｍ２０２０ＰＬ型）で測定した。この測定を３回繰り返し、Ｌ＊、ａ＊の値（平均値）を求めた。
（６）審美性
５名のパネラーで、肌着試料の審美性を目視により評価した。優れているを１点、劣っているを０点として、以下の基準で判定した。
○：優れている（４点以上）
△：どちらともいえない（３点又は２点）
×：劣っている（１点以下）
【００４２】
実施例１
ＡＮ９６重量％、アクリル酸メチル（以下、ＭＡという）４重量％からなるＡＮ系重合体（３０℃ジメチルホルムアミド中での極限粘度［η］：１．２）１０部を４８％のロダンソーダ水溶液９０部に溶解した紡糸原液を、常法に従って紡糸、延伸した後乾球／湿球＝１２０℃／６０℃の雰囲気下で乾燥、湿熱処理して単繊維繊度１．７ｄｔｅｘの原料繊維を得た。
【００４３】
該原料繊維に、水加ヒドラジンの２０重量％水溶液中で、９８℃×５時間架橋導入処理を行った。本処理により、架橋が導入され、窒素含有量が増加する。なお窒素増加量は、原料繊維と架橋導入処理後の繊維を元素分析にて窒素含有量を求め、その差から算出した。
次に、苛性ソーダの３重量％水溶液中で、９０℃×２時間加水分解処理を行い、純水で洗浄した。この処理により、繊維にＮａ型カルボキシル基が５．５ｍｅｑ／ｇ生成していた。
【００４４】
該加水分解後の繊維を、ハイドロサルファイトナトリウム塩（以下ＳＨＳという）の１重量％水溶液中で、９０℃×２時間還元処理を行い、純水で洗浄した。続いて、硝酸の３重量％水溶液中、９０℃×２時間酸処理を行った。これにより５．５ｍｅｑ／ｇ生成していたＮａ型カルボキシル基は全量がＨ型カルボキシル基になっていた。該酸処理後の繊維を純水中に投入し、濃度４８％の苛性ソーダ水溶液をＨ型カルボキシル基に対し、Ｎａ中和度７０モル％になるように添加し、６０℃×３時間塩型調整処理を行った。以上の工程を経た繊維を水洗、油剤付与、脱水、乾燥し、高白度吸湿性合成繊維（吸湿性繊維Ａ）を得た。得られた繊維の飽和吸湿率、白度（原綿及び洗濯５回後）、色安定性（各種の条件下における変色のし難さ）を調べ、塩型カルボキシル基量、窒素増加量とともに表１に示した。
【００４５】
得られた高白度吸湿性合成繊維（吸湿性繊維Ａ）を３０重量％、一般市販ポリエステル繊維である東洋紡績（株）製ポリエステル繊維タイプ２Ｔ３８を７０重量％混綿し、常法に従って紡績して綿番手５０／１の紡績糸試料を作製した。該紡績糸試料を、口径１４寸総針１０２０本の丸編機でフライス編して、目付けが約２００ｇ／ｍ^２の編地試料を作製した。この編地試料を高圧液流染色機にて１１０℃×３０分のポリエステル蛍光染料染色を行い、染色編地を得た。この染色編地試料を縫製し、紳士用肌着試料を作製して、この試料の白度、洗濯耐久性、審美性を調べ表２に示した。
【００４６】
【表１】

【００４７】
比較例１
ＡＮ９４重量％、ＭＡ６重量％からなるＡＮ系重合体を用いた以外は実施例１と同様にして吸湿性合成繊維（吸湿性繊維Ｂ）を得た。得られた繊維の吸湿率、白度、色安定性を調べ、塩型カルボキシル基量、窒素増加量とともに表１に示した。かかる吸湿性合成繊維（吸湿性繊維Ｂ）を用いて、実施例１と同様の方法で紳士用肌着試料を作製した。評価結果は表２に併記した。
【００４８】
実施例２
水加ヒドラジンによる架橋導入処理工程を経た繊維を、加水分解する前に１０重量％の硝酸水溶液中、９０℃で２時間酸処理した以外は実施例１と同様にして、高白度吸湿性合成繊維（吸湿性繊維Ｃ）を得た。この繊維の特性も表１に示した。
【００４９】
得られた高白度吸湿性合成繊維（吸湿性繊維Ｃ）を３０重量％、一般市販アクリル繊維である東洋紡績（株）製アクリル繊維「Ｋ８６２−１Ｔ３８」を７０重量％混綿し、常法に従って紡績して１／６４番手のアクリル混紡品である紡績糸を作製し、口径１４寸総針１０２０本の丸編機でフライス編して目付け約１８０ｇ／ｍ^２の編地試料を作製した。この編地試料を常圧液流染色機にてアクリル蛍光染料染色を行い、染色編地を得た。この染色編地試料を縫製し、実施例２の婦人用肌着試料を作製した。この試料の特性も表２に併記した。
【００５０】
比較例２
還元処理、酸処理及び塩型調整処理を行わなかった以外は実施例１と同様にして、吸湿性合成繊維（吸湿性繊維Ｄ）を得た。得られた吸湿性合成繊維（吸湿性繊維Ｄ）を用いる以外実施例２と同様にして、比較例２の婦人用肌着試料を作製した。この試料の特性も表２に併記した。
【００５１】
実施例３、比較例３
実施例２で得られた高白度吸湿性合成繊維（吸湿性繊維Ｃ）を３０重量％、一般市販アクリル繊維である日本エクスラン工業（株）製アクリル繊維「Ｋ８１５−０．９Ｔ３８」を３０重量％、「Ｋ６５−３．０Ｔ５１」を４０重量％、混綿し、常法に従って紡績して毛番手１／４６の高白度吸湿性合成繊維を含有する紡績糸試料を作製した。またそれとは別に羊毛６０トップを２０重量％混綿し、同社製アクリル繊維「Ｋ８１５−０．９Ｔ５１」を２０重量％、「Ｋ８２３−２．４Ｔ５１」を２０重量％、「Ｋ６５−３．０Ｔ５１」を４０重量％混紡し常法に従って紡績して毛番手１／４６の毛混紡品である紡績糸試料を作製した。次に丸編機にて該高白度吸湿性合成繊維混紡糸を編地の裏側に、該毛混紡糸を表側に使用し、交編して袋編した編物試料を作製した。この編物試料をスイム染色機にてアクリル蛍光染料染色を行い、染色編地を得た。この染色編物試料を縫製し、実施例３の婦人用肌着試料を得た。この肌着試料の特性も表２に併記した。なお、比較例３は比較例２で得られた吸湿性合成繊維（吸湿性繊維Ｄ）を用いた以外は、実施例３と同様にして得られた婦人用肌着試料であり、この試料の特性も表２に併記した。
【００５２】
実施例４、比較例４
実施例２で作製した丸編試料を常圧液流染色機で常法のアクリル染色方法にて、アクリルサイドの染色を行い、鮮明なサックスの色相を得た。この染色丸編試料を縫製し、実施例４の婦人用肌着試料を作製し、この試料の洗濯耐久性及び審美性を調べ表２に示した。比較例４は比較例２の吸湿性合成繊維（吸湿性繊維Ｄ）を用いた以外は、実施例４と同様にして得られた試料であり、この試料の洗濯耐久性及び審美性を調べ表２に併記した。
【００５３】
【表２】

【００５４】
高白度吸湿性合成繊維である吸湿性繊維Ａを用いた実施例１の紳士用肌着は優れた白度を有し、洗濯耐久性も優れたものであり、洗濯前後の審美性も優れていた。これに対し、白度及び白度の安定性に劣る吸湿性繊維Ｂを用いた比較例２の紳士用肌着は、白度はそこそこであるものの、審美性に劣り、洗濯により吸湿性繊維が着色するため、洗濯耐久性も悪く、洗濯後の審美性はさらに悪化した。また、高白度吸湿性合成繊維である吸湿性繊維Ｃを用いた実施例２，３の肌着は、白度、洗濯耐久性、審美性ともに優れていた。最も白度に劣る吸湿性繊維Ｄを用いた比較例２，３の肌着は、本発明の肌着に比べ白度に劣り、吸湿性繊維Ｄの色相のため審美性にも劣るものであった。実施例４はアクリル繊維をサックスに染色したものであるが、高白度吸湿性合成繊維である吸湿性繊維Ｃを用いることで鮮明なサックスの色相の肌着を得ることができた。また吸湿性繊維Ｄを用いた比較例４の肌着は、該繊維自体の持つピンク味の色相のため、実施例４と同様の処方で染めたにもかかわらず、赤味がかった水色で鮮明といえるものではなく、審美性に劣るものであった。
【００５５】
【発明の効果】
本発明の吸湿性肌着は、高白度吸湿性合成繊維を少なくとも一部に用いたことで、吸湿性肌着に要求される基本物性並びに吸湿特性を維持しながら、従来の吸湿性繊維の色が不安定であるという欠点の改良を可能としたものであり、優れた審美性を有する高白度の吸湿性肌着、さらに鮮明な色、特に鮮明な淡色の吸湿性肌着をも提供することができる。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to hygroscopic underwear. More specifically, it has moisture absorption and desorption properties, is excellent in processability, and has improved whiteness more than conventional products, and has excellent color stability in which the color hardly changes even after repeated exposure and washing in the dyeing process. The present invention relates to a hygroscopic undergarment using at least a part of a high whiteness hygroscopic synthetic fiber.
[0002]
[Prior art]
In order to prevent discomfort such as stuffiness and stickiness when worn, hygroscopic fibers are used in some underwear. As such a hygroscopic fiber, there has been proposed a means disclosed in JP-A-1-299624 in which a deliquescent salt is impregnated into a superabsorbent fiber. Fibers obtained by this means are easy to process into knits, woven fabrics, non-woven fabrics, etc., have a high moisture absorption / desorption rate, and have practical performance without falling off of the moisture absorbent, but the fiber surface is hydrogel. For this reason, it does not satisfy the fact that it is tacky when it absorbs moisture and it is difficult to apply it to underwear that directly touches the skin, and it has not been able to satisfy the flame retardancy and antibacterial properties that have recently been increasing as social needs.
[0003]
As a method for solving these problems, a means disclosed in Japanese Patent Laid-Open No. 5-132858 has been proposed. However, in this method, when the amount of the salt-type carboxyl group exceeds 4.5 meq / g, the tensile strength becomes 0.9 cN / dtex or less, resulting in insufficient fiber properties to withstand various processes. , Which has become a barrier to further increase the moisture absorption rate. When the increase in the nitrogen content introduced by the treatment with the hydrazine-based compound to obtain a highly hygroscopic fiber having a fiber strength of 0.9 cN / dtex or more is set to more than 8.0% by weight, However, there is a problem that the amount of the salt-type carboxyl group introduced becomes small and the hygroscopicity becomes low.
[0004]
Furthermore, the fiber obtained by the method disclosed in Japanese Patent Application Laid-Open No. 5-132858 has a drawback that the field of application is limited because it exhibits a deep pink to deep brown color. The invention of Japanese Patent Application Laid-Open No. 9-158040 proposed as a means for overcoming this drawback is to carry out acid treatment A after crosslinking treatment with a hydrazine-based compound, and to carry out acid treatment B after hydrolysis treatment with alkali. , And the whiteness can be considerably improved. Still, it is colored pale pink to light brown, and underwear using such a hygroscopic fiber is unsuitable for white underwear because it retains the hue of the fiber as it is, and is a colored product. However, because of the hue of the fiber, the color became dull and a clear color was not obtained, and it was not suitable for light-colored underwear. Japanese Patent Application Laid-Open No. 2000-303353 discloses that a hydrolysis treatment is performed in an oxygen-free atmosphere as a method for improving whiteness. However, the fibers obtained by these methods are colored by repeating the oxidative exposure treatment and washing in the dyeing process, and have the disadvantage of poor color stability. At present, it is not enough to give satisfaction.
[0005]
[Problems to be solved by the invention]
The present invention provides a high-whiteness hygroscopic synthetic composition which has improved the disadvantage that the color of the conventional hygroscopic fiber is unstable while maintaining the basic physical properties required of the fiber and the properties which the hygroscopic fiber should have. An object of the present invention is to provide a hygroscopic undergarment using fibers at least in part.
[0006]
[Means for Solving the Problems]
An object of the present invention described above is a hygroscopic synthetic fiber having a saturated moisture absorption of 10% by weight or more at 20 ° C. and 65% RH, wherein the whiteness of the fiber is JIS-Z-8729. L * 85 or more and a * ± 6 (hereinafter, L * and a * are in accordance with the display method described in JIS-Z-8729) and within the range of JIS-L0217-103 method ( At least one high-whiteness hygroscopic synthetic fiber whose discoloration of the fiber after washing 5 times with a washing process using Kao Corporation's attack is 3-4 or more as evaluated by JIS-L0805 contamination gray scale is used. It can be achieved by the hygroscopic underwear used for the part.
[0007]
Further, it is an object of the present invention that the high whiteness hygroscopic synthetic fiber used for hygroscopic underwear has a saturated water absorption of less than 300% by weight, preferably 200% by weight or less, more preferably 150% by weight or less. Acrylic fibers composed of an acrylonitrile-based polymer having a hygroscopic synthetic fiber as a copolymer component containing less than 5% by weight of a (meth) acrylate compound were subjected to a cross-linking treatment with a hydrazine-based compound, hydrolysis and reduction treatment. It can be suitably achieved by the fact that the whiteness of the fiber after washing five times is within a range of L * 85 or more and a * ± 6.
[0008]
In addition, the discoloration of the underwear using the high whiteness hygroscopic synthetic fiber for at least a part of the underwear after washing five times by the washing treatment according to JIS-L-0217-103 method is a gray scale for JIS-L-0805 contamination. This is achieved by having a grade of 3-4 or higher.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail. The high-whiteness hygroscopic synthetic fiber used in the present invention must be a hygroscopic synthetic fiber having a saturated hygroscopicity at 20 ° C. and 65% RH of 10% by weight or more. It is more preferably 15% by weight, and there is no need to limit the upper limit as long as there is no sticky feeling in the moisture absorption state, but it is extremely difficult to exceed 100% by weight while substantially maintaining a refreshing feeling. If the content is less than 10% by weight, discomfort such as stuffiness cannot be prevented, so that it cannot be adopted. Further, the whiteness of the fiber must be L * 85 or more and a * ± 6. When L * is less than 85 and a * is out of the range of ± 6, it can no longer be said that the whiteness is excellent. Preferably, L * is 86 or more and a * is within a range of ± 4.
[0010]
Further, the high whiteness hygroscopic synthetic fiber used for at least a part of the hygroscopic underwear of the present invention is characterized in that even in the washing treatment, the discoloration of whiteness is extremely small, that is, the washing durability is excellent. Yes, specifically, the discoloration of the fiber after washing 5 times by the washing treatment according to the JIS-L0217-103 method (the detergent used is an attack made by Kao Corporation) was evaluated by JIS-L0805 contamination gray scale by 3-4. It is more than class. In addition, even after the washing process, the whiteness of the fiber is preferably L * 85 or more and a * ± 6, more preferably L * is 86 or more and a * is ± 5. . The color change of the whiteness due to the washing process is a change to redness, and the difference (Δa *) between the value of a * which is a parameter representing redness before and after washing is 0.7 or less, preferably 0.6 or less. It is desirable.
[0011]
The saturated white water-absorbing synthetic fiber used in at least a part of the hygroscopic underwear of the present invention preferably has a saturated water absorption of less than 300% by weight. If the saturated water absorption is 300% by weight or more, the fiber surface becomes sticky when water is absorbed, which is not preferable for use in underwear.
[0012]
It is desirable that the whiteness of the high-whiteness hygroscopic synthetic fiber does not decrease even in a treatment such as oxidative exposure in the dyeing process. Specifically, the hydrogen peroxide concentration is 0.5% by weight, and NaOH is used. Discoloration (exposure durability) of the fiber after exposure to hydrogen peroxide subjected to exposure at pH 10, bath ratio 1/50, 80 ° C. for 60 minutes, grade 3 or more as evaluated by JIS-L0805 contamination gray scale It is preferable that the discoloration (standing stability) after standing at 80 ° C. for 16 hours in the presence of water exceeding the saturated water absorption is 3-4 or higher as evaluated by JIS-L0805 contamination gray scale.
[0013]
Here, the value (grade) of the exposure durability was such that the fiber sample was put into an aqueous solution of 0.5% by weight of hydrogen peroxide adjusted to pH 10 with NaOH such that the bath ratio between the fiber sample and the aqueous solution became 1/50. Then, the degree of discoloration from the color of the fiber sample subjected to the exposure treatment at 80 ° C. for 60 minutes from the color of the fiber sample before the exposure treatment was evaluated by JIS-L0805 contamination gray scale.
[0014]
The value (grade) of the standing stability was such that the sample fiber was immersed in pure water, taken out after being sufficiently hydrated, and taken out at a temperature of 80 ° C. to maintain a sufficient amount of water to maintain water exceeding the saturated water absorption. Close the container so that more than half of the container is a space, put it in a thermostat adjusted to 80 ° C, remove it after 16 hours, dehydrate and dry the fiber, and measure the degree of discoloration from the fiber sample before treatment. It is obtained by evaluating with JIS-L0805 gray scale for contamination.
Note that the saturated water absorption is an amount obtained by subtracting the weight of the same sample fiber after drying (105 ° C. × 16 hours) from the weight after centrifugal dehydration of the sufficiently hydrated fiber (160 G × 5 minutes). The saturated water absorption is a value obtained by dividing the saturated water absorption by the weight of the sample fiber after drying (105 ° C. × 16 hours) and expressing the value in%.
[0015]
The hygroscopic undergarment of the present invention is an undergarment using such a high whiteness hygroscopic synthetic fiber in at least a part thereof, even if it is composed only of the high whiteness hygroscopic synthetic fiber, cotton, wool, polyester It may be mixed with other fibers such as fiber and acrylic fiber. In the case of mixing with other fibers, the type and mixing ratio of the other fibers are not particularly limited, and may be appropriately selected according to the characteristics required for each undergarment. Examples of the mixed form of the high-whiteness hygroscopic synthetic fiber include cotton blending in spinning and twisting in the spinning / twisting process, normal knitting in fabric production, and two- to three-layer knitting. However, the present invention is not limited to this.
[0016]
The method for producing the hygroscopic underwear of the present invention is not particularly limited as long as the high whiteness hygroscopic synthetic fiber is used for at least a part thereof, and a usual method can be employed. For example, a method of producing a woven or knitted fabric by blending a high whiteness hygroscopic synthetic fiber and another fiber into a spun yarn, cutting and sewing such a woven or knitted fabric to produce a hygroscopic underwear, or A method of producing a woven or knitted fabric by mixing and weaving synthetic fibers with other fibers and other fibers to produce a woven or knitted fabric, and cutting and sewing the woven or knitted fabric to produce a hygroscopic undergarment. In the moisture-absorbing underwear of the present invention, underwear may be manufactured using the woven or knitted fabric alone, or the woven or knitted fabric may be used as a part of the underwear.
[0017]
Since the hygroscopic underwear of the present invention uses the high whiteness hygroscopic synthetic fiber in at least a part thereof, it is possible to obtain a high whiteness hygroscopic underwear having excellent aesthetics, and to obtain a clearer color. In particular, a clear light-colored hygroscopic underwear can be obtained. For example, in the case of underwear with high whiteness, the whiteness is improved by mixing with a fiber having excellent whiteness, or by blending with other fibers to form a spun yarn or a knitted fabric, then exposing and bleaching. By doing so, it is possible to obtain an underwear having a whiteness equal to or higher than the high whiteness hygroscopic synthetic fiber.
In addition, a clear color, particularly a clear light color underwear, can be obtained by dyeing a fiber other than the high whiteness hygroscopic synthetic fiber by a usual method.
[0018]
Such underwear is excellent in aesthetics and cleanliness without being affected by the hue of the conventional light-absorbent synthetic fibers colored pale pink to pale brown. In addition, in the underwear of the present invention, the discoloration of the underwear after washing 5 times by the washing treatment according to the JIS-L-0217-103 method is grade 3 or higher as evaluated by JIS-L-0805 contamination gray scale. Is preferred. Therefore, it is desirable that fibers other than the above-mentioned highly hygroscopic synthetic fibers to be mixed have such washing durability.
[0019]
The hygroscopic underwear of the present invention includes women's, men's, children's underwear such as girdle, shorts, bras, camisole, petticoat, pantyhose, stockings, tights, running shirts, and socks.
[0020]
As described above, in the hygroscopic underwear of the present invention, the amount of the high-whiteness hygroscopic synthetic fiber is not limited, but in the sense that the characteristics of the fiber are clearly expressed as underwear, 5% by weight or more, The content is more preferably at least 10% by weight, most preferably at least 15% by weight. On the other hand, it goes without saying that the fiber material other than the high whiteness hygroscopic synthetic fiber occupies the residue, but it is not always necessary to use one kind of material, and it is naturally possible to mix two or more kinds of materials.
[0021]
The method for producing a high whiteness hygroscopic synthetic fiber used in the hygroscopic undergarment of the present invention includes a method for producing an acrylic fiber comprising an acrylonitrile-based polymer in which a (meth) acrylate compound is less than 5% by weight as a copolymer component. In addition, a method for producing a high whiteness hygroscopic synthetic fiber, which comprises subjecting a hydrazine-based compound to a crosslinking introduction treatment, hydrolysis, and reduction treatment, is recommended. Hereinafter, the method will be described in detail.
[0022]
The starting acrylic fiber (hereinafter sometimes referred to as acrylonitrile fiber) is a fiber formed of an AN polymer containing acrylonitrile (hereinafter, referred to as AN) in an amount of 40% by weight or more, preferably 50% by weight or more. , Short fibers, tows, yarns, knitted fabrics, non-woven fabrics, and the like, and in-process products, waste fibers, and the like. The AN-based polymer may be any of an AN homopolymer and a copolymer of AN and another monomer, and a (meth) acrylate compound is most preferably used as a monomer to be copolymerized with AN. However, if it is unavoidable to use it, it must be less than 5% by weight, more preferably 4.0% by weight or less. The notation with (meth) indicates both acrylate and methacrylate. Examples of the ester compound which may be used as a copolymer component if it is less than 5% by weight include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, and (meth) acrylic acid. Examples thereof include dimethylaminoethyl and diethylaminoethyl (meth) acrylate. Other copolymerizable components include sulfonic acid group-containing monomers such as methallyl sulfonic acid and p-styrene sulfonic acid and salts thereof; monomers such as styrene and vinyl acetate and the like which are copolymerizable with AN. It is not particularly limited as long as it is a body, but it is desirable to copolymerize 5 to 20% by weight of a vinyl ester compound represented by vinyl acetate. Such vinyl esters include vinyl acetate, vinyl propionate, vinyl butyrate, and the like.
[0023]
The acrylic fiber is subjected to a cross-linking treatment with a hydrazine-based compound, a cross-link is formed in the sense that the acrylic fiber is no longer dissolved in a solvent for the acrylic fiber, and at the same time, an increase in the nitrogen content occurs. Means are not particularly limited. A means capable of adjusting the increase in the nitrogen content by this treatment to 1.0 to 10% by weight is preferable. However, even if the increase in the nitrogen content is 0.1 to 1.0% by weight, it is adopted in the present invention. Any method can be adopted as long as it is a means for obtaining a high whiteness hygroscopic synthetic fiber. As means for adjusting the increase in the nitrogen content to 1.0 to 10% by weight, means for treating in a 5 to 60% by weight aqueous solution of a hydrazine compound at a temperature of 50 to 120 ° C. within 5 hours. Is industrially preferred. In order to suppress the increase in the nitrogen content at a low rate, these conditions may be set in a milder direction according to the teaching of reaction engineering. Here, the increase in the nitrogen content refers to the difference between the nitrogen content of the raw acrylic fiber and the nitrogen content of the acrylic fiber into which the crosslinking with the hydrazine compound has been introduced.
[0024]
The hydrazine-based compound used herein is not particularly limited, and may be, for example, hydrazine hydrate, hydrazine sulfate, hydrazine hydrochloride, hydrazine bromate, hydrazine carbonate, and the like, as well as ethylenediamine, guanidine sulfate, guanidine hydrochloride, guanidine phosphate, Compounds having a plurality of amino groups such as melamine are exemplified.
[0025]
Fibers that have undergone such a hydrazine-based cross-linking treatment may be subjected to an acid treatment. This treatment contributes to improving the color stability of the fiber.
Examples of the acid used herein include, but are not particularly limited to, aqueous solutions of mineral acids such as nitric acid, sulfuric acid, and hydrochloric acid, and organic acids. Before this treatment, the hydrazine-based compound remaining in the crosslinking introduction treatment is sufficiently removed. Conditions for the acid treatment are not particularly limited, but the fibers to be treated are immersed in an aqueous solution having an acid concentration of generally 5 to 20% by weight, preferably 7 to 15% by weight at a temperature of 50 to 120 ° C for 0.5 to 10 hours. There is an example of doing.
[0026]
The fiber that has undergone the cross-linking treatment step with a hydrazine-based compound or the fiber that has been further subjected to an acid treatment is subsequently hydrolyzed with an aqueous alkaline metal salt solution. By this treatment, the CN groups remaining without being involved in the crosslinking introduction treatment of the acrylic fiber by the hydrazine-based compound treatment and the CN groups remaining when the acid treatment is performed after the crosslinking treatment are partially removed. The hydrolysis of the CONH ₂ groups hydrolyzed by the acid treatment proceeds. These groups form a carboxyl group by hydrolysis. However, since the drug used is an alkaline metal salt, a metal salt-type carboxyl group is eventually formed. Examples of the alkaline metal salt used here include an alkali metal hydroxide, an alkaline earth metal hydroxide, and an alkali metal carbonate. The concentration of the alkaline metal salt to be used is not particularly limited, but a means for treating in an aqueous solution of 1 to 10% by weight, more preferably 1 to 5% by weight at a temperature of 50 to 120 ° C. within 1 to 10 hours is industrially used. It is also preferable in physical properties.
[0027]
Here, examples of the type of the metal salt, that is, the salt type of the carboxyl group include alkali metals such as Li, Na and K, and alkaline earth metals such as Mg, Ca and Ba. The extent to which hydrolysis proceeds, that is, the amount of metal salt-type carboxyl groups to be formed, should be controlled to 4 to 10 meq / g, which can be easily performed by a combination of the concentration of the drug, the temperature, and the processing time in the above-described processing. Can be. The fibers that have undergone such a hydrolysis step may or may not have CN groups remaining. If CN groups remain, their reactivity may be used to provide additional functions.
[0028]
The reducing agent used in the subsequent reduction treatment is one or two selected from the group consisting of hydrosulfite salts, thiosulfates, sulfites, nitrites, thiourea dioxide, ascorbate, and hydrazine compounds. Drugs combining more than one type can be suitably used. The conditions for the reduction treatment are not particularly limited, but examples include immersing the fibers to be treated in an aqueous solution having a drug concentration of approximately 0.5 to 5% by weight at a temperature of 50 to 120 ° C. for 30 minutes to 5 hours. The reduction treatment may be performed simultaneously with the above-mentioned hydrolysis, or may be performed after the hydrolysis.
[0029]
Thus, a high whiteness hygroscopic synthetic fiber used for the hygroscopic undergarment of the present invention is obtained.In order to further stabilize the color, the fiber which has been subjected to the above-mentioned reduction treatment step is subjected to an acid treatment, and the metal salt type carboxyl is applied. The group is converted to H-type, and a part of the H-type carboxyl group is converted to a metal salt (salt-type adjusting treatment) by a metal salt treatment selected from Li, Na, K, Ca, Mg, Ba, and Al to form H-type. It is preferable to adjust the molar ratio of / metal salt type to 90/10 to 0/100.
[0030]
Examples of the acid used for the acid treatment include aqueous solutions of mineral acids such as nitric acid, sulfuric acid, and hydrochloric acid, and organic acids, but are not particularly limited. The conditions of the acid treatment are not particularly limited, but the fibers to be treated are generally immersed in an aqueous solution having an acid concentration of 1 to 10% by weight, preferably 2 to 10% by weight at a temperature of 50 to 120 ° C for 2 to 10 hours. Examples are given.
[0031]
The metal type of the metal salt used in the salt type adjustment treatment is selected from Li, Na, K, Ca, Mg, Ba, and Al, but Na, K, Ca, Mg, and the like are particularly recommended. The type of salt may be any water-soluble salt of these metals, and examples thereof include hydroxides, halides, nitrates, sulfates, and carbonates. Specifically, Na salts and Na ₂ CO ₃ as Na salts, KOH as K salts, Ca (OH) ₂ , Ca (NO ₃ ) ₂ , and CaCl ₂ as Ca salts are representatives of the respective metals. ₂ is preferred.
[0032]
The H-type / metal salt-type molar ratio of the carboxyl group is within the above-mentioned range, but is appropriately set together with the type of metal depending on the function to be imparted to the fiber. In the concrete implementation of the salt type adjustment treatment, a 0.2 to 30% by weight aqueous solution of a metal salt is prepared in a treatment tank, and the fiber to be treated is immersed at 20 to 80 ° C. for about 0.25 to 5 hours, or There is a method such as spraying the aqueous solution. In order to control the above ratio, a salt type adjustment treatment in the presence of a buffer is preferable. As the buffer, those having a pH buffer range of 5.0 to 9.2 are suitable. Further, the type of the metal salt of the metal salt type carboxyl group is not limited to one type, and two or more types may be mixed.
[0033]
When the salt type adjustment treatment is performed using a substance having low water solubility such as a metal salt compound such as Ca, Mg, and Ba, the molar ratio of H type / metal salt type is changed from H type carboxyl group to metal type in this step. There is some difficulty in increasing the salt form. In such a case, as a pretreatment after the acid treatment and as a pretreatment of the salt form adjustment treatment, the H-form carboxyl group is adjusted in an acid treatment step by adjusting the pH of the carboxyl group with an aqueous solution of caustic soda or caustic potash or the like. It is recommended to perform a sum treatment (pH = 5th to 11th). With such a prescription, the carboxyl group after the neutralization treatment is in a state in which the H type and the Na or K type coexist, so that the next salt type adjustment treatment is easily performed by exchanging Ca or the like with Na or K. As it progresses, the difficulties raised are resolved.
[0034]
The means for producing the acrylic fiber, which is the starting material, is not particularly limited, and means employed in the production of ordinary clothing fibers can be used.
Further, it is preferable to use such a fiber as a starting fiber, but it is not always necessary to finish the final step, and even if the acrylic fiber is in the process of being manufactured, or the final fiber is subjected to spinning or the like. The later one may be used. Above all, as the starting acrylic fiber, a fiber before drawing and heat treatment after drawing in the middle of the manufacturing process of acrylic fiber (an original spinning solution of AN polymer is spun according to a conventional method and drawn and oriented, but it is dried and densified, wet heat When fibers which have not been subjected to heat treatment such as relaxation treatment, especially wet or dry / wet spinning and water-swelled gel-like fibers after stretching: the degree of water swelling is 30 to 150%, the dispersibility of the fibers in the treatment liquid is increased. This is desirable because the permeability of the treatment liquid into the fiber is improved, and the introduction of the cross-linking and the hydrolysis reaction are performed uniformly and promptly.
[0035]
It is to be noted that these starting acrylic fibers are filled in a container having a stirring function and a temperature control function, and the above-described steps are sequentially performed, or a plurality of containers are arranged in a row to continuously perform the above-described steps. However, it is desirable from the viewpoint of safety, uniform processing property, and the like on the apparatus. As such an apparatus, a dyeing machine is exemplified.
[0036]
As another method of producing a high whiteness hygroscopic synthetic fiber used for the underwear of the present invention, the acrylic fiber is subjected to a crosslinking introduction treatment with a hydrazine compound described above, a hydrolysis treatment, a reduction treatment, an acid treatment, and A method in which the reduction treatment and the acid treatment are repeated is exemplified. By repeating the reduction treatment and the acid treatment, whiteness and color stability are improved, L * 85 or more, a * ± 6 within the range, and high durability moisture absorption of washing durability of 3-4 class or more. The synthetic synthetic fiber is obtained. According to this method, even if the (meth) acrylate compound is 5% by weight or more as a copolymer component of the acrylonitrile-based polymer forming the acrylic fiber, a high whiteness which can be employed in the hygroscopic underwear of the present invention. Although a degree of hygroscopic synthetic fiber can be obtained, since the reduction treatment and the acid treatment are required to be repeated, the fiber properties are reduced, or the production cost is increased. It is more advantageous to adopt a manufacturing method.
[0037]
The hygroscopic underwear of the present invention employs the high whiteness hygroscopic synthetic fiber described above in at least a part thereof, and has a hygroscopic property, so that it is possible to prevent stuffiness and stickiness when worn, and it is even more excellent. It is also possible to provide a hygroscopic underwear of a high degree of whiteness having an aesthetic property, and a vivid color, particularly a clear light-colored hygroscopic underwear.
[0038]
[Action]
The reason why the high-whiteness hygroscopic synthetic fiber used in at least a part of the hygroscopic underwear of the present invention has excellent whiteness and color stability, which has not been sufficiently elucidated, has been described in detail above. Think like. That is, when a crosslinked structure is introduced by a hydrazine-based compound, when the acrylic fiber as a raw material contains 5% by weight or more of a (meth) acrylate compound as a copolymerization component, a portion of carbonyl carbon in the copolymerization component is used. When the hydrazine-based compound reacts with the compound, a bond containing an oxygen molecule is introduced into the cross-linking structure, resulting in easy color development, that is, poor color stability. Is suppressed at the raw material stage, so that color development is suppressed, and it is presumed that color development is unlikely to occur even by a treatment such as hydrogen peroxide exposure treatment or repeated washing. Even when the (meth) acrylic ester compound is contained in an amount of 5% by weight or more, the molecular structure that develops color by repeating the reduction treatment and the acid treatment can be obtained by a treatment such as a hydrogen peroxide exposure treatment or a repeated washing. This is presumed to be due to having a stable molecular structure that is difficult to change.
[0039]
【Example】
Hereinafter, the present invention will be described specifically with reference to examples. Parts and percentages in the examples are on a weight basis unless otherwise specified. The metal salt type carboxyl group content, whiteness, saturated moisture absorption and the like were determined by the following methods. Washing in the examples was carried out according to the JIS-L0217-103 method (the detergent used was an attack manufactured by Kao Corporation), and this was repeated five times.
[0040]
(1) Metal salt type carboxyl group amount (meq / g)
About 1 g of sufficiently dried sample fiber was precisely weighed (Xg), and 200 ml of water was added thereto. Then, a 1 mol / l aqueous hydrochloric acid solution was added to the mixture while heating at 50 ° C. to pH 2, and then 0.1 mol / l. A titration curve was obtained with a 1NaOH aqueous solution according to a conventional method. From the titration curve, the NaOH aqueous solution consumed amount (Yml) consumed by the carboxyl group was determined, and the carboxyl group amount (meq / g) was calculated by the following equation.
(Amount of carboxyl group) = 0.1Y / X
Separately, a titration curve was similarly obtained without adjusting the pH to 2 by adding a 1 mol / l aqueous hydrochloric acid solution during the above-mentioned carboxyl group amount measurement operation, and the H-type carboxyl group amount (meq / g) was obtained. From these results, the amount of metal salt-type carboxyl groups was calculated by the following equation.
(Metal salt type carboxyl group amount) = (carboxyl group amount) − (H type carboxyl group amount)
[0041]
(2) 4.0 g of sample fiber opened by a fiber whiteness card machine was filled in a rotary colorimetric cell (35 ml transparent cylindrical cell), and a color difference meter TC-1500MC-88 manufactured by Tokyo Denshoku Co., Ltd. ( (D65 light source) while rotating at a rate of 60 times / minute. This measurement was repeated three times, and the values of L * and a * (average values) were determined.
(3) Saturated moisture absorption (%)
About 5.0 g of the sample fiber is dried with a hot air drier at 105 ° C. for 16 hours, and the weight is measured (W1 g). Next, the sample is placed in a thermostat at a temperature of 20 ° C. and a relative humidity of 65% for 24 hours. The weight of the sample thus absorbed is measured (W2 g). From the above measurement results, it was calculated by the following equation.
(Moisture absorption%) = {(W2-W1) / W1} × 100
(4) Saturated water absorption (%)
The sample fiber is sufficiently immersed in pure water, hydrated, taken out, centrifugally dehydrated (160 G × 5 minutes), and the water absorption obtained by subtracting the weight of the same sample fiber after drying (105 ° C. × 16 hours) is obtained. And the value obtained by dividing the weight after drying on the left as a percentage.
(5) Whiteness of the underwear A part of the underwear was measured with a color difference meter (M2020PL type) manufactured by Macbeth. This measurement was repeated three times, and the values of L * and a * (average values) were determined.
(6) Aesthetics The aesthetics of the underwear samples were visually evaluated by five panelists. An evaluation was made according to the following criteria, with 1 being excellent and 0 being poor.
：: Excellent (4 points or more)
△: Neither of them (3 or 2 points)
×: Inferior (1 point or less)
[0042]
Example 1
10 parts of AN-based polymer (intrinsic viscosity [η]: 1.2 in dimethylformamide at 30 ° C .: 1.2) consisting of 96% by weight of AN and 4% by weight of methyl acrylate (hereinafter referred to as MA); 90 parts of a 48% aqueous solution of rhoda soda The spinning solution dissolved in the above was spun and stretched in a conventional manner, and then dried and wet-heat-treated in an atmosphere of dry bulb / wet bulb = 120 ° C./60° C. to obtain a raw fiber having a single fiber fineness of 1.7 dtex.
[0043]
The raw material fiber was subjected to a crosslinking introduction treatment in a 20% by weight aqueous solution of hydrazine hydrate at 98 ° C. for 5 hours. This treatment introduces crosslinking and increases the nitrogen content. The amount of nitrogen increase was calculated from the difference between the nitrogen content of the raw fiber and the fiber after the cross-linking treatment by elemental analysis.
Next, hydrolysis treatment was performed at 90 ° C. for 2 hours in a 3% by weight aqueous solution of caustic soda, and the resultant was washed with pure water. As a result of this treatment, 5.5 meq / g of Na-type carboxyl groups were generated in the fibers.
[0044]
The hydrolyzed fibers were subjected to a reduction treatment in a 1% by weight aqueous solution of sodium hydrosulfite (hereinafter referred to as SHS) at 90 ° C. for 2 hours, and washed with pure water. Subsequently, an acid treatment was performed in a 3% by weight aqueous solution of nitric acid at 90 ° C. for 2 hours. As a result, all of the Na-type carboxyl groups generated at 5.5 meq / g were H-type carboxyl groups. The acid-treated fiber is put into pure water, and an aqueous solution of caustic soda having a concentration of 48% is added so that the degree of neutralization of Na with respect to the H-type carboxyl group is 70 mol%, and the salt form is adjusted at 60 ° C. for 3 hours. Processing was performed. The fiber after the above steps was washed with water, applied with an oil agent, dehydrated and dried to obtain a high whiteness hygroscopic synthetic fiber (hygroscopic fiber A). The obtained fiber was examined for saturation moisture absorption, whiteness (after raw cotton and after washing 5 times), and color stability (difficulty of discoloration under various conditions). It was shown to.
[0045]
The obtained high-whiteness hygroscopic synthetic fiber (hygroscopic fiber A) was mixed with 30% by weight, and 70% by weight of a polyester fiber type 2T38 manufactured by Toyobo Co., Ltd., which is a commercially available polyester fiber, and spun according to a conventional method. A 50/1 cotton spun yarn sample was prepared. The spun yarn sample was milled and knitted with a circular knitting machine having 1020 needles having a diameter of 14 to prepare a knitted fabric sample having a basis weight of about 200 g / m ² . The knitted fabric sample was dyed with a polyester fluorescent dye at 110 ° C. for 30 minutes using a high-pressure jet dyeing machine to obtain a dyed knitted fabric. The dyed knitted fabric sample was sewn to prepare a men's underwear sample, and the whiteness, washing durability, and aesthetics of this sample were examined.
[0046]
[Table 1]

[0047]
Comparative Example 1
A hygroscopic synthetic fiber (hygroscopic fiber B) was obtained in the same manner as in Example 1 except that an AN polymer composed of 94% by weight of AN and 6% by weight of MA was used. The moisture absorption, whiteness, and color stability of the obtained fiber were examined. Using this hygroscopic synthetic fiber (hygroscopic fiber B), a men's underwear sample was produced in the same manner as in Example 1. The evaluation results are also shown in Table 2.
[0048]
Example 2
High whiteness hygroscopic synthesis was performed in the same manner as in Example 1 except that the fiber which had undergone the cross-linking introduction treatment step with hydrazine hydrate was subjected to an acid treatment in a 10% by weight aqueous nitric acid solution at 90 ° C. for 2 hours before hydrolysis. Fiber (hygroscopic fiber C) was obtained. The properties of this fiber are also shown in Table 1.
[0049]
30% by weight of the obtained high-whiteness hygroscopic synthetic fiber (hygroscopic fiber C) and 70% by weight of acrylic fiber "K862-1T38" manufactured by Toyobo Co., Ltd., which is a commercially available acrylic fiber, are mixed in a usual manner. Spinning was performed to produce a 1 / 64th-count acrylic mixed spun yarn, which was then milled and knitted with a circular knitting machine having 1020 needles having a diameter of 14 to prepare a knitted fabric sample having a basis weight of about 180 g / m ² . This knitted fabric sample was dyed with an acrylic fluorescent dye using a normal pressure jet dyeing machine to obtain a dyed knitted fabric. The dyed knitted fabric sample was sewn to prepare a women's underwear sample of Example 2. The characteristics of this sample are also shown in Table 2.
[0050]
Comparative Example 2
A hygroscopic synthetic fiber (hygroscopic fiber D) was obtained in the same manner as in Example 1 except that the reduction treatment, the acid treatment, and the salt type adjustment treatment were not performed. A women's underwear sample of Comparative Example 2 was produced in the same manner as in Example 2 except that the obtained hygroscopic synthetic fiber (hygroscopic fiber D) was used. The characteristics of this sample are also shown in Table 2.
[0051]
Example 3, Comparative Example 3
30% by weight of the high whiteness hygroscopic synthetic fiber (hygroscopic fiber C) obtained in Example 2, and 30% by weight of acrylic fiber "K815-0.9T38" manufactured by Nippon Xlan Industrial Co., Ltd., which is a commercially available acrylic fiber % And "K65-3.0T51" in a ratio of 40% by weight, and spun according to a conventional method to prepare a spun yarn sample containing a high whiteness hygroscopic synthetic fiber having a 1/46 hair count. Separately, 20% by weight of wool 60 top is blended, and 20% by weight of the company's acrylic fiber "K815-0.9T51", 20% by weight of "K823-2.4T51", and "K65-3.0T51". A 40% by weight blend was spun and spun according to a conventional method to prepare a spun yarn sample which was a wool blended product having a hair count of 1/46. Next, using a circular knitting machine, the high whiteness hygroscopic synthetic fiber blended yarn was used on the back side of the knitted fabric, and the wool blended yarn was used on the front side, and a knitted sample was produced by cross-knitting and bag-knitting. This knitted fabric sample was dyed with an acrylic fluorescent dye using a swim dyeing machine to obtain a dyed knitted fabric. This dyed knitted fabric sample was sewn to obtain a women's underwear sample of Example 3. The properties of this underwear sample are also shown in Table 2. Comparative Example 3 is a women's underwear sample obtained in the same manner as in Example 3 except that the hygroscopic synthetic fiber (hygroscopic fiber D) obtained in Comparative Example 2 was used. Are also shown in Table 2.
[0052]
Example 4, Comparative Example 4
The circular knitted sample prepared in Example 2 was dyed on the acrylic side by an ordinary acrylic dyeing method using a normal pressure liquid jet dyeing machine to obtain a clear sax hue. The dyed circular knitted sample was sewn to prepare a women's underwear sample of Example 4, and the washing durability and aesthetics of this sample were examined and shown in Table 2. Comparative Example 4 is a sample obtained in the same manner as in Example 4 except that the hygroscopic synthetic fiber (hygroscopic fiber D) of Comparative Example 2 was used. The sample was examined for washing durability and aesthetics. 2
[0053]
[Table 2]

[0054]
The men's underwear of Example 1 using the hygroscopic fiber A, which is a high whiteness hygroscopic synthetic fiber, has excellent whiteness, excellent washing durability, and excellent aesthetics before and after washing. Was. On the other hand, the gentleman's underwear of Comparative Example 2 using the hygroscopic fiber B having inferior whiteness and whiteness stability has a good degree of whiteness, but is inferior in aesthetics and the hygroscopic fiber is colored by washing. Therefore, the washing durability was poor, and the aesthetics after washing were further deteriorated. The underwear of Examples 2 and 3 using the hygroscopic fiber C, which is a high whiteness hygroscopic synthetic fiber, was excellent in whiteness, washing durability and aesthetics. The underwear of Comparative Examples 2 and 3 using the hygroscopic fiber D having the lowest whiteness was inferior in whiteness to the undergarment of the present invention, and also poor in aesthetics due to the hue of the hygroscopic fiber D. In Example 4, the acrylic fiber was dyed on a saxophone. Underwear having a clear sax hue could be obtained by using the hygroscopic fiber C which is a high whiteness hygroscopic synthetic fiber. Further, the undergarment of Comparative Example 4 using the hygroscopic fiber D was clear with reddish light blue despite being dyed by the same formulation as in Example 4 because of the pink hue of the fiber itself. It could not be said that it was inferior in aesthetics.
[0055]
【The invention's effect】
The hygroscopic undergarment of the present invention uses the high whiteness hygroscopic synthetic fiber for at least a part of the fiber, while maintaining the basic physical properties and hygroscopic properties required for the hygroscopic undergarment, while maintaining the color of the conventional hygroscopic fiber. It is possible to improve the disadvantage of being unstable, and can provide a high-whiteness hygroscopic underwear having excellent aesthetics, and also provide a clear color, particularly a clear light-colored hygroscopic underwear. .

Claims

A hygroscopic synthetic fiber having a saturated moisture absorption of 10% by weight or more at 20 ° C. and 65% RH, wherein the whiteness of the fiber is L * 85 or more and a * ± in the display method described in JIS-Z-8729. 6. High whiteness hygroscopicity in which the discoloration of the fiber after washing 5 times in the washing process according to JIS-L0217-103 is 3-4 or more as evaluated by JIS-L0805 contamination gray scale. Hygroscopic underwear using synthetic fibers at least in part.

2. The hygroscopic undergarment according to claim 1, wherein the high whiteness hygroscopic synthetic fiber has a saturated water absorption of less than 300% by weight.

A high whiteness hygroscopic synthetic fiber is used as a copolymer component in an acrylic fiber composed of an acrylonitrile-based polymer containing less than 5% by weight of a (meth) acrylic acid ester compound, for introducing a cross-linking treatment with a hydrazine-based compound, hydrolysis, and reduction. The hygroscopic undergarment according to claim 1 or 2, wherein the undergarment has been subjected to a treatment.

2. The display method according to JIS-Z-8729, wherein the whiteness of the high-whiteness hygroscopic synthetic fiber after washing five times is L * 85 or more and a * ± 6 in the display method described in JIS-Z-8729. 4. The moisture-absorbing undergarment according to any one of to 3).

An undergarment using at least a part of the high-whiteness hygroscopic synthetic fiber according to any one of claims 1 to 4, wherein discoloration of the undergarment after washing five times by a washing treatment according to JIS-L0217-103 method is JIS. -L-0805 A moisture-absorbing undergarment characterized by being a Grade 3-4 or higher as evaluated on a gray scale for contamination.