JP2788140B2 - Method for producing polypropylene-based composite short fiber and nonwoven fabric - Google Patents

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【０００１】[0001]

【産業上の利用分野】本発明は，伸縮性，嵩高性及び柔
軟性に優れた不織布を得るに好適なポリプロピレン系複
合短繊維と不織布の製造方法に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polypropylene-based composite short fiber and a method for producing a nonwoven fabric suitable for obtaining a nonwoven fabric having excellent stretchability, bulkiness and flexibility.

【０００２】[0002]

【従来の技術】従来から，熱可塑性合成複合繊維からな
る不織布として，融点の異なる複数の重合体成分を並列
型あるいは芯鞘型等に配置した複合繊維からなる不織布
が広範に用いられている。この複合繊維からなる不織布
は，異成分複合繊維の特徴である潜在捲縮性を利用し，
不織布加工時に捲縮を発現させることにより伸縮性を付
与したもので，主としてサポータ，パツプ材あるいはお
むつ等の医療衛生材用素材として用いられている。例え
ば，特公昭５５−２６２０３号公報には，ブテン−１を
含有した三次元共重合体からなる複合繊維が，また，特
開平２−１２７５５３号公報には，ブテン−１を含有し
た共重合体からなる複合繊維から構成された不織布が提
案されている。しかしながら，この不織布では，ブテン
−１を含有した三次元共重合体からなるため熱接着性は
向上するものの，伸縮性や嵩高性が劣るのみならず風合
いが硬くなるという問題があった。また，特公昭５２−
３７０９７号公報には，ポリプロピレン重合体とポリエ
チレン重合体とからなる複合繊維が提案されているが，
この複合繊維からなる不織布には，不織布作成時の両成
分間の剥離により不織布面上に毛羽が生じ，製品の品位
が低下するという問題があった。さらに，特開平２−１
９１７２０号公報公報には，ポリプロピレン重合体とエ
チレン−プロピレンランダム共重合体とからなる複合繊
維及びその製造方法が提案されている。この複合繊維
は，ポリプロピレン重合体のＱ値（重量平均分子量／数
平均分子量）を小さくして螺旋状の捲縮を発現させるこ
とにより伸縮性が付与されたものである。しかしなが
ら，この複合繊維には，ポリプロピレン重合体のＱ値が
小さいため，捲縮発現処理時の熱処理温度領域が制限さ
れて工程管理が困難であるという問題が，また，この複
合繊維からなる不織布には，その品位が低下するという
問題があった。2. Description of the Related Art Conventionally, as a nonwoven fabric made of a thermoplastic synthetic conjugate fiber, a nonwoven fabric made of a conjugate fiber in which a plurality of polymer components having different melting points are arranged in a parallel type or a core-sheath type has been widely used. The non-woven fabric made of this composite fiber utilizes the latent crimpability, which is a characteristic of hetero-component composite fiber,
A material that has been given elasticity by exhibiting crimping during nonwoven fabric processing, and is mainly used as a material for medical hygiene materials such as supporters, wrappers, and diapers. For example, Japanese Patent Publication No. 55-26203 discloses a conjugate fiber comprising a three-dimensional copolymer containing butene-1, and Japanese Patent Application Laid-Open No. 2-127553 discloses a copolymer containing butene-1. Has been proposed. However, in this nonwoven fabric, although it is made of a three-dimensional copolymer containing butene-1, heat adhesion is improved, but there is a problem that not only stretchability and bulkiness are inferior but also the feel becomes hard. In addition,
JP-A-37097 proposes a composite fiber composed of a polypropylene polymer and a polyethylene polymer.
The nonwoven fabric made of the composite fiber has a problem that fluff is generated on the surface of the nonwoven fabric due to separation between the two components at the time of preparing the nonwoven fabric, and the quality of the product is deteriorated. Furthermore, Japanese Patent Laid-Open No. 2-1
JP-A-91720 proposes a composite fiber comprising a polypropylene polymer and an ethylene-propylene random copolymer and a method for producing the same. This conjugate fiber is provided with elasticity by reducing the Q value (weight average molecular weight / number average molecular weight) of the polypropylene polymer to develop a helical crimp. However, this composite fiber has a problem that the Q value of the polypropylene polymer is small, so that the heat treatment temperature range at the time of crimping treatment is limited and process control is difficult. Had a problem that its quality was deteriorated.

【０００３】[0003]

【発明が解決しようとする課題】本発明は，前記問題を
解決し，伸縮性，嵩高性及び柔軟性に優れ，特に医療衛
生材用素材に適した不織布を得るに好適なポリプロピレ
ン系複合短繊維と不織布を効率よく製造することができ
る方法を提供しようとするものである。DISCLOSURE OF THE INVENTION The present invention solves the above problems and has excellent stretchability, bulkiness and flexibility, and is particularly suitable for obtaining a nonwoven fabric suitable for use as a material for medical hygiene materials. And a method for efficiently producing a nonwoven fabric.

【０００４】[0004]

【課題を解決するための手段】本発明者らは，前記問題
を解決すべく鋭意検討の結果，本発明に到達した。すな
わち，本発明は， １）９２重量％以上９７重量％以下のプロピレンと３重
量％以上８重量％以下のエチレンがランダム共重合され
たポリプロピレン系共重合体成分Ａと，９７重量％以上
１００重量％以下のプロピレンと０重量％以上３重量％
以下のエチレンが共重合されたポリプロピレン系共重合
体成分Ｂとを複合成分とし，複合短繊維としたときのメ
ルトフローレート値が１５ｇ／１０分以上４５ｇ／１０
分以下となるようにし，重合体成分Ａと重合体成分Ｂの
溶融後のメルトフローレート値比（Ｂ／Ａ）を１／１〜
６／１とし，かつ重合体成分Ａと重合体成分Ｂの吐出線
速度を２〜１０ｍ／分として溶融複合紡糸し，得られた
未延伸複合繊維を５０℃以上かつ繊維相互が融着しない
温度で熱延伸し，次いで得られた延伸複合繊維に捲縮付
与処理を施し，仕上げ油剤を付与した後乾燥し，所定長
さに切断して短繊維とすることを特徴とするポリプロピ
レン系短繊維の製造方法，Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, have reached the present invention. That is, the present invention provides: 1) a polypropylene-based copolymer component A obtained by random copolymerization of 92% by weight to 97% by weight of propylene and 3% by weight to 8% by weight of ethylene; % Or less of propylene and 0% to 3% by weight
A melt flow rate of not less than 15 g / 10 min and not more than 45 g / 10 min when the following polypropylene-based copolymer component B obtained by copolymerizing ethylene is used as a composite component to obtain a conjugate short fiber.
And the melt flow rate ratio (B / A) of the polymer component A and the polymer component B after melting is 1/1 to 1 / min.
6/1, and melt-composite spinning the polymer component A and the polymer component B at a discharge linear velocity of 2 to 10 m / min, and a temperature at which the obtained undrawn composite fiber is 50 ° C. or higher and at which the fibers are not fused to each other. A hot drawing process, and then applying a crimping treatment to the obtained drawn conjugate fiber, applying a finishing oil agent, drying, and cutting into a predetermined length to obtain a short fiber of polypropylene. Production method,

【０００５】２）９２重量％以上９７重量％以下のプロ
ピレンと３重量％以上８重量％以下のエチレンがランダ
ム共重合され，かつＱ値（重量平均分子量／数平均分子
量）が８以下のポリプロピレン系共重合体成分Ａと，９
７重量％以上１００重量％以下のプロピレンと０重量％
以上３重量％以下のエチレンが共重合され，かつＱ値
（重量平均分子量／数平均分子量）が５以上８以下のポ
リプロピレン系共重合体成分Ｂとを複合成分とし，複合
短繊維としたときのメルトフローレート値が１５ｇ／１
０分以上４５ｇ／１０分以下となるようにし，重合体成
分Ａと重合体成分Ｂの溶融後のメルトフローレート値比
（Ｂ／Ａ）を１／１〜６／１とし，かつ重合体成分Ａと
重合体成分Ｂの吐出線速度を２〜１０ｍ／分として溶融
複合紡糸し，得られた未延伸複合繊維を５０℃以上かつ
繊維相互が融着しない温度で熱延伸し，次いで得られた
延伸複合繊維に捲縮付与処理を施し，仕上げ油剤を付与
した後乾燥し，所定長さに切断して短繊維とすることを
特徴とするポリプロピレン系短繊維の製造方法，[0005] 2) A polypropylene system in which 92% by weight to 97% by weight of propylene and 3% by weight to 8% by weight of ethylene are randomly copolymerized and the Q value (weight average molecular weight / number average molecular weight) is 8 or less. Copolymer component A, 9
7% to 100% by weight of propylene and 0% by weight
When 3% by weight or less of ethylene is copolymerized and a polypropylene-based copolymer component B having a Q value (weight average molecular weight / number average molecular weight) of 5 or more and 8 or less is used as a composite component, a composite staple fiber is obtained. Melt flow rate value is 15g / 1
The melt flow rate value ratio (B / A) after melting of the polymer component A and the polymer component B is set to 1/1 to 6/1, and the polymer component A and the polymer component B are set to 1/1 to 6/1. A and the polymer component B were melt-spun at a discharge linear velocity of 2 to 10 m / min, and the obtained undrawn composite fiber was hot-drawn at a temperature of 50 ° C. or higher and at a temperature at which the fibers did not fuse with each other. A method of producing a polypropylene-based short fiber, comprising applying a crimping treatment to the drawn conjugate fiber, applying a finishing oil agent, drying, and cutting into a predetermined length to obtain a short fiber.

【０００６】３）９２重量％以上９７重量％以下のプロ
ピレンと３重量％以上８重量％以下のエチレンがランダ
ム共重合され，かつＱ値（重量平均分子量／数平均分子
量）が８以下のポリプロピレン系共重合体成分Ａと，９
７重量％以上１００重量％以下のプロピレンと０重量％
以上３重量％以下のエチレンが共重合され，かつＱ値
（重量平均分子量／数平均分子量）が５以上８以下のポ
リプロピレン系共重合体成分Ｂとを複合成分とし，複合
短繊維としたときのメルトフローレート値が１５ｇ／１
０分以上４５ｇ／１０分以下となるようにし，重合体成
分Ａと重合体成分Ｂの溶融後のメルトフローレート値比
（Ｂ／Ａ）を１／１〜６／１とし，かつ重合体成分Ａと
重合体成分Ｂの吐出線速度を２〜１０ｍ／分として溶融
複合紡糸し，得られた未延伸複合繊維を５０℃以上かつ
繊維相互が融着しない温度で熱延伸して下記条件（１）
〜（３）を満足する複合繊維とし，次いで得られた延伸
複合繊維に捲縮付与処理を施し，仕上げ油剤を付与した
後乾燥し，所定長さに切断して短繊維とすることを特徴
とするポリプロピレン系短繊維の製造方法， （１）熱処理前の複合短繊維の共重合体成分Ａ部分の複
屈折と共重合体成分Ｂ部分の複屈折が共に０．０２以上
であること， （２）広角Ｘ線回折法により測定される熱処理前の複合
短繊維の結晶体積が１０００００ų 以下であること， （３）小角Ｘ線散乱法により測定される熱処理前の複合
短繊維の長周期が１３０Å未満であること，[0006] 3) A polypropylene system in which 92% by weight to 97% by weight of propylene and 3% by weight to 8% by weight of ethylene are randomly copolymerized and the Q value (weight average molecular weight / number average molecular weight) is 8 or less. Copolymer component A, 9
7% to 100% by weight of propylene and 0% by weight
When 3% by weight or less of ethylene is copolymerized and a polypropylene-based copolymer component B having a Q value (weight average molecular weight / number average molecular weight) of 5 or more and 8 or less is used as a composite component, a composite staple fiber is obtained. Melt flow rate value is 15g / 1
The melt flow rate value ratio (B / A) after melting of the polymer component A and the polymer component B is set to 1/1 to 6/1, and the polymer component A and the polymer component B are set to 1/1 to 6/1. A and the polymer component B are melt-spun at a discharge linear velocity of 2 to 10 m / min, and the obtained undrawn conjugate fiber is hot-drawn at a temperature of 50 ° C. or more and at a temperature at which the fibers are not fused to each other. )
(3), then subjecting the obtained stretched conjugate fiber to crimping treatment, applying a finishing oil agent, drying, and cutting into a predetermined length to obtain short fibers. (1) that the birefringence of the copolymer component A portion and the birefringence of the copolymer component B portion of the conjugate short fiber before heat treatment are both 0.02 or more; ) the crystal volume of the composite short fibers before the heat treatment as measured by wide angle X-ray diffraction method is 100000 ³ or less, the long period of composite short fibers before the heat treatment as measured by (3) small-angle X-ray scattering method 130Å Less than,

【０００７】４）９２重量％以上９７重量％以下のプロ
ピレンと３重量％以上８重量％以下のエチレンがランダ
ム共重合されたポリプロピレン系共重合体成分Ａと，９
７重量％以上１００重量％以下のプロピレンと０重量％
以上３重量％以下のエチレンが共重合されたポリプロピ
レン系共重合体成分Ｂとを複合成分とし，複合短繊維と
したときのメルトフローレート値が１５ｇ／１０分以上
４５ｇ／１０分以下となるようにし，重合体成分Ａと重
合体成分Ｂの溶融後のメルトフローレート値比（Ｂ／
Ａ）を１／１〜６／１とし，かつ重合体成分Ａと重合体
成分Ｂの吐出線速度を２〜１０ｍ／分として溶融複合紡
糸し，得られた未延伸複合繊維を５０℃以上かつ繊維相
互が融着しない温度で熱延伸し，次いで得られた延伸複
合繊維に捲縮付与処理を施し，仕上げ油剤を付与した後
乾燥し，所定長さに切断して短繊維とし，次いで得られ
た複合短繊維５０重量％以上を用いてカードウエブを作
成し，このカードウエブを多孔性支持部材上に載置し，
圧力が３０ｋｇ／ｃｍ² 未満の流体噴流により前記ウエ
ブに流体絡合処理を施した後，圧力が５０ｋｇ／ｃｍ²
以上の流体噴流により前記ウエブに流体絡合処理を施し
てウエブを構成する前記複合短繊維相互を三次元的に絡
合させ，引き続きウエブに乾熱処理を施して水分を除去
するとともに複合短繊維に捲縮を発現させることを特徴
とする不織布の製造方法，4) A polypropylene copolymer component A obtained by random copolymerization of 92% by weight to 97% by weight of propylene and 3% by weight to 8% by weight of ethylene;
7% to 100% by weight of propylene and 0% by weight
A melt flow rate value of 15 g / 10 min or more and 45 g / 10 min or less when a composite short component and a polypropylene copolymer component B in which not less than 3 wt% of ethylene is copolymerized is used as a composite component. And the melt flow rate ratio (B / M) of the polymer component A and the polymer component B after melting.
A) is set to 1/1 to 6/1, and the melt linear spinning is performed at a discharge linear velocity of the polymer component A and the polymer component B of 2 to 10 m / min. The fiber is hot-drawn at a temperature at which the fibers do not fuse with each other, and then the obtained drawn composite fiber is subjected to crimping treatment, applied with a finishing oil agent, dried, cut into a predetermined length into short fibers, and then obtained. A card web is prepared using at least 50% by weight of the composite staple fiber, and the card web is placed on a porous support member.
After subjecting the web to a fluid entanglement treatment by a fluid jet having a pressure of less than 30 kg / cm ^{2, the} pressure is reduced to 50 kg / cm ^2.
The web is subjected to a fluid entanglement treatment by the above-described fluid jet to three-dimensionally entangle the composite staple fibers constituting the web with each other. Subsequently, the web is subjected to a dry heat treatment to remove water and to form a conjugate staple fiber. A method for producing a nonwoven fabric, characterized by exhibiting crimp;

【０００８】５）９２重量％以上９７重量％以下のプロ
ピレンと３重量％以上８重量％以下のエチレンがランダ
ム共重合され，かつＱ値（重量平均分子量／数平均分子
量）が８以下のポリプロピレン系共重合体成分Ａと，９
７重量％以上１００重量％以下のプロピレンと０重量％
以上３重量％以下のエチレンが共重合され，かつＱ値
（重量平均分子量／数平均分子量）が５以上８以下のポ
リプロピレン系共重合体成分Ｂとを複合成分とし，複合
短繊維としたときのメルトフローレート値が１５ｇ／１
０分以上４５ｇ／１０分以下となるようにし，重合体成
分Ａと重合体成分Ｂの溶融後のメルトフローレート値比
（Ｂ／Ａ）を１／１〜６／１とし，かつ重合体成分Ａと
重合体成分Ｂの吐出線速度を２〜１０ｍ／分として溶融
複合紡糸し，得られた未延伸複合繊維を５０℃以上かつ
繊維相互が融着しない温度で熱延伸し，次いで得られた
延伸複合繊維に捲縮付与処理を施し，仕上げ油剤を付与
した後乾燥し，所定長さに切断して短繊維とし，次いで
得られた複合短繊維５０重量％以上を用いてカードウエ
ブを作成し，このカードウエブを多孔性支持部材上に載
置し，圧力が３０ｋｇ／ｃｍ² 未満の流体噴流により前
記ウエブに流体絡合処理を施した後，圧力が５０ｋｇ／
ｃｍ² 以上の流体噴流により前記ウエブに流体絡合処理
を施してウエブを構成する前記複合短繊維相互を三次元
的に絡合させ，引き続きウエブに乾熱処理を施して水分
を除去するとともに複合短繊維に捲縮を発現させること
を特徴とする不織布の製造方法，5) A polypropylene system in which 92% by weight to 97% by weight of propylene and 3% by weight to 8% by weight of ethylene are randomly copolymerized and the Q value (weight average molecular weight / number average molecular weight) is 8 or less. Copolymer component A, 9
7% to 100% by weight of propylene and 0% by weight
When 3% by weight or less of ethylene is copolymerized and a polypropylene-based copolymer component B having a Q value (weight average molecular weight / number average molecular weight) of 5 or more and 8 or less is used as a composite component, a composite staple fiber is obtained. Melt flow rate value is 15g / 1
The melt flow rate value ratio (B / A) after melting of the polymer component A and the polymer component B is set to 1/1 to 6/1, and the polymer component A and the polymer component B are set to 1/1 to 6/1. A and the polymer component B were melt-spun at a discharge linear velocity of 2 to 10 m / min, and the obtained undrawn composite fiber was hot-drawn at a temperature of 50 ° C. or higher and at a temperature at which the fibers did not fuse with each other. The drawn conjugate fiber is subjected to crimping treatment, applied with a finishing oil agent, dried, cut into a predetermined length to obtain short fibers, and then a card web is prepared using 50% by weight or more of the obtained conjugate short fibers. After placing the card web on a porous support member and subjecting the web to a fluid entanglement treatment by a fluid jet having a pressure of less than 30 kg / cm ² , the pressure is reduced to 50 kg / cm ^2.
The web is subjected to a fluid entanglement treatment by a fluid jet of at least ² cm so that the composite short fibers constituting the web are three-dimensionally entangled with each other. A method for producing a nonwoven fabric, characterized by expressing crimps in fibers,

【０００９】６）９２重量％以上９７重量％以下のプロ
ピレンと３重量％以上８重量％以下のエチレンがランダ
ム共重合され，かつＱ値（重量平均分子量／数平均分子
量）が８以下のポリプロピレン系共重合体成分Ａと，９
７重量％以上１００重量％以下のプロピレンと０重量％
以上３重量％以下のエチレンが共重合され，かつＱ値
（重量平均分子量／数平均分子量）が５以上８以下のポ
リプロピレン系共重合体成分Ｂとを複合成分とし，複合
短繊維としたときのメルトフローレート値が１５ｇ／１
０分以上４５ｇ／１０分以下となるようにし，重合体成
分Ａと重合体成分Ｂの溶融後のメルトフローレート値比
（Ｂ／Ａ）を１／１〜６／１とし，かつ重合体成分Ａと
重合体成分Ｂの吐出線速度を２〜１０ｍ／分として溶融
複合紡糸し，得られた未延伸複合繊維を５０℃以上かつ
繊維相互が融着しない温度で熱延伸して下記条件（１）
〜（３）を満足する複合繊維とし，次いで得られた延伸
複合繊維に捲縮付与処理を施し，仕上げ油剤を付与した
後乾燥し，所定長さに切断して短繊維とし，次いで得ら
れた複合短繊維５０重量％以上を用いてカードウエブを
作成し，このカードウエブを多孔性支持部材上に載置
し，圧力が３０ｋｇ／ｃｍ² 未満の流体噴流により前記
ウエブに流体絡合処理を施した後，圧力が５０ｋｇ／ｃ
ｍ² 以上の流体噴流により前記ウエブに流体絡合処理を
施してウエブを構成する前記複合短繊維相互を三次元的
に絡合させ，引き続きウエブに乾熱処理を施して水分を
除去するとともに複合短繊維に下記条件（４）〜（６）
を満足させ，かつ捲縮を発現させることを特徴とする不
織布の製造方法， （１）熱処理前の複合短繊維の共重合体成分Ａ部分の複
屈折と共重合体成分Ｂ部分の複屈折が共に０．０２以上
であること， （２）広角Ｘ線回折法により測定される熱処理前の複合
短繊維の結晶体積が１０００００ų 以下であること， （３）小角Ｘ線散乱法により測定される熱処理前の複合
短繊維の長周期が１３０Å未満であること， （４）熱処理後の複合短繊維の共重合体成分Ａ部分の複
屈折と共重合体成分Ｂ部分の複屈折が共に上記熱処理前
の複合短繊維の共重合体成分Ａ部分の複屈折と共重合体
成分Ｂ部分の複屈折よりそれぞれ低いこと， （５）広角Ｘ線回折法により測定される熱処理後の複合
短繊維の結晶体積が２０００００ų 以上であること， （６）小角Ｘ線散乱法により測定される熱処理後の複合
短繊維の長周期が１３０Å以上であること， を要旨とするものである。6) A polypropylene system in which 92% by weight to 97% by weight of propylene and 3% by weight to 8% by weight of ethylene are randomly copolymerized and the Q value (weight average molecular weight / number average molecular weight) is 8 or less. Copolymer component A, 9
7% to 100% by weight of propylene and 0% by weight
When 3% by weight or less of ethylene is copolymerized and a polypropylene-based copolymer component B having a Q value (weight average molecular weight / number average molecular weight) of 5 or more and 8 or less is used as a composite component, a composite staple fiber is obtained. Melt flow rate value is 15g / 1
The melt flow rate value ratio (B / A) after melting of the polymer component A and the polymer component B is set to 1/1 to 6/1, and the polymer component A and the polymer component B are set to 1/1 to 6/1. A and the polymer component B are melt-spun at a discharge linear velocity of 2 to 10 m / min, and the obtained undrawn conjugate fiber is hot-drawn at a temperature of 50 ° C. or more and at a temperature at which the fibers are not fused to each other. )
To (3), and then subjected to a crimping treatment on the obtained drawn composite fiber, applied with a finishing oil agent, dried, cut into a predetermined length to obtain short fibers, and then obtained. A card web is prepared by using 50% by weight or more of the composite staple fiber, and the card web is placed on a porous support member, and the web is subjected to a fluid entanglement treatment by a fluid jet having a pressure of less than 30 kg / cm ^2. After that, the pressure is 50kg / c
subjected to fluid entangling treatment to said web by m ² or more fluid jets to the composite short fibers each other three-dimensionally entangled constituting the web, subsequently the composite short to remove the water is subjected to dry heat treatment the web The following conditions (4) to (6) for the fiber
And (1) the birefringence of the copolymer component A portion and the birefringence of the copolymer component B portion of the conjugate short fiber before heat treatment are satisfied. it is both 0.02 or more, (2) the crystal volume of the composite short fibers before the heat treatment as measured by wide angle X-ray diffraction method is 100000 ³ or less, as measured by (3) small-angle X-ray scattering method (4) Both the birefringence of the copolymer component A portion and the birefringence of the copolymer component B portion of the composite short fiber after the heat treatment are before the heat treatment. The birefringence of the copolymer component A portion and the birefringence of the copolymer component B portion of the composite staple fiber of (1), (5) the crystal volume of the composite staple fiber after heat treatment measured by a wide-angle X-ray diffraction method Is not less than 200,000 $ ³ , (6) The long cycle of the conjugate short fibers after heat treatment measured by the small-angle X-ray scattering method is 130 ° or more.

【００１０】次に，本発明を詳細に説明する。まず，本
発明の複合短繊維の製造方法に関して説明する。本発明
の方法では，まず，９２重量％以上９７重量％以下のプ
ロピレンと３重量％以上８重量％以下のエチレンがラン
ダム共重合されたポリプロピレン系共重合体成分Ａと，
９７重量％以上１００重量％以下のプロピレンと０重量
％以上３重量％以下のエチレンが共重合されたポリプロ
ピレン系共重合体成分Ｂとから構成される複合短繊維を
製造する。Next, the present invention will be described in detail. First, the method for producing a conjugate short fiber of the present invention will be described. In the method of the present invention, first, a polypropylene-based copolymer component A obtained by random copolymerization of 92% by weight or more and 97% by weight or less of propylene and 3% by weight or more and 8% by weight or less of ethylene,
A conjugate short fiber composed of 97% by weight or more and 100% by weight or less of propylene and 0% by weight or more and 3% by weight or less of a polypropylene-based copolymer component B copolymerized with ethylene is produced.

【００１１】重合体成分Ａは，９２重量％以上９７重量
％以下のプロピレンと３重量％以上８重量％以下のエチ
レンが共重合され，かつ繊維形成性を有し曵糸性よく溶
融紡糸できるものである。このエチレンの共重合は共重
合体の融点降下と熱収縮性に大きく影響し，共重合量に
比例して共重合体の融点を降下させ，かつ熱収縮性を増
大させる。この共重合量が３重量％未満であると，共重
合体の融点降下が小さくなり，複合短繊維を熱処理した
とき捲縮発現性が低下し，しかも熱収縮率が低下するの
で好ましくない。しかしながら，この共重合量が８重量
％を超えると，重合するに際し重合溶媒（炭化水素）に
可溶性の副生物の生成割合が増加して生産性が低下する
ので工業的に不経済となり好ましくない。したがって，
この共重合量は，３重量％以上８重量％以下とし，好ま
しくは３．２重量％以上７．０重量％以下，特に好まし
くは３．５重量％以上６．０重量％以下とするのがよ
い。また，重合体成分Ａは，前記３重量％以上８重量％
以下のエチレンと９２重量％以上９７重量％以下のプロ
ピレンがランダム共重合されたものである。このランダ
ム共重合は，共重合体の均一な熱収縮特性と曵糸性の点
で極めて重要である。他の共重合形態としてブロツク共
重合があるが，この共重合では，ポリプロピレンの構造
の中にエチレンの構造部がブロツク単位で存在するた
め，共重合体の熱収縮特性が不均一となり，しかも曵糸
性が極度に低下するという問題が生じるので好ましくな
い。The polymer component A is obtained by copolymerizing 92% by weight to 97% by weight of propylene and 3% by weight to 8% by weight of ethylene, and has a fiber-forming property and can be melt-spun with good spinnability. It is. The copolymerization of ethylene greatly affects the melting point of the copolymer and the heat shrinkage, and lowers the melting point of the copolymer and increases the heat shrinkage in proportion to the copolymerization amount. If the copolymerization amount is less than 3% by weight, the decrease in the melting point of the copolymer becomes small, and when heat treatment is performed on the conjugate short fibers, the crimp development property is reduced, and the heat shrinkage rate is undesirably reduced. However, if the copolymerization amount exceeds 8% by weight, the rate of formation of by-products soluble in the polymerization solvent (hydrocarbon) during the polymerization increases, and the productivity is lowered. Therefore,
The copolymerization amount is from 3% by weight to 8% by weight, preferably from 3.2% by weight to 7.0% by weight, particularly preferably from 3.5% by weight to 6.0% by weight. Good. In addition, the polymer component A contains 3% by weight or more and 8% by weight or more.
The following ethylene and 92 to 97% by weight of propylene are randomly copolymerized. This random copolymerization is extremely important in terms of uniform heat shrinkage properties and spinnability of the copolymer. Another form of copolymerization is block copolymerization. However, in this copolymerization, the heat shrinkage characteristics of the copolymer become non-uniform because the structural unit of ethylene is present in block units in the structure of polypropylene. It is not preferable because the problem that the yarn property is extremely reduced occurs.

【００１２】前記重合体成分Ｂは，９７重量％以上１０
０重量％以下のプロピレンと０重量％以上３重量％以下
のエチレンが共重合され，かつ繊維形成性を有し曵糸性
よく溶融紡糸できるものである。このエチレンの共重合
は，前述したように，共重合体の融点降下と熱収縮性に
大きく影響し，共重合量に比例して共重合体の融点を降
下させ，かつ熱収縮性を増大させるものであり，この重
合体成分Ｂでは，融点降下と熱収縮性の増大を抑制する
必要がある。すなわち，重合体成分Ａと重合体成分Ｂと
の間で融点及び熱収縮特性の差が小さくなりすぎると，
複合短繊維を熱処理したとき捲縮発現性が低下するので
好ましくない。したがって，この共重合量は，０重量％
以上３重量％以下とし，好ましくは２．５重量％以下，
特に好ましくは２重量％以下とするのがよい。The polymer component B is 97% by weight or more and 10% or more.
The polymer is copolymerized with 0% by weight or less of propylene and 0% by weight or more and 3% by weight or less of ethylene, has fiber-forming properties, and can be melt-spun with good spinnability. As described above, this copolymerization of ethylene greatly affects the drop in the melting point of the copolymer and the heat shrinkage, and lowers the melting point of the copolymer in proportion to the copolymerization amount and increases the heat shrinkage. In the polymer component B, it is necessary to suppress a decrease in melting point and an increase in heat shrinkage. That is, if the difference between the melting point and the heat shrinkage property between the polymer component A and the polymer component B becomes too small,
When the conjugate short fiber is heat-treated, the crimping property is lowered, which is not preferable. Therefore, the copolymerization amount is 0% by weight.
Not more than 3% by weight, preferably not more than 2.5% by weight,
Particularly preferably, the content is 2% by weight or less.

【００１３】本発明では，溶融複合紡糸は，通常の溶融
複合紡糸装置を用いて行うことができる。溶融複合紡糸
に際しては，前記共重合体成分Ａとしてメルトフローレ
ート値が５ｇ／１０分以上４０ｇ／１０分以下のもの
を，前記共重合体成分Ｂとしてメルトフローレート値が
１５ｇ／１０分以上８０ｇ／１０分以下のものを用い，
両重合体を複合して得られた複合短繊維のメルトフロー
レート値が１５ｇ／１０分以上４５ｇ／１０分以下とな
るようにして溶融紡糸する必要がある。この複合短繊維
のメルトフローレート値は，ＡＳＴＭ Ｄ １２３８
（Ｌ）に記載の方法により測定されるものであり，この
メルトフローレート値が１５ｇ／１０分未満であると，
複合短繊維の熱収縮応力が高くなって捲縮力や伸縮力，
嵩高性を大きくすることができるが，重合体の曵糸性の
みならず次工程の熱延伸性が低下したり，溶融紡糸時の
紡糸温度が高く設定されるためポリプロピレン系重合体
が分解して多量のガスが発生し，紡糸室の環境を悪化さ
せたりするので好ましくない。一方，メルトフローレー
ト値が４５ｇ／１０分を超えると，複合短繊維の熱収縮
力が低下するため伸縮性と嵩高性に優れた不織布を得る
ことができず，また，ポリプロピレン系重合体の重合度
が低すぎ分解して多量のガスが発生し，紡糸室の環境を
悪化させたりするので好ましくない。したがって，この
メルトフローレート値は，１５ｇ／１０分以上４５ｇ／
１０分以下とし，好ましくは１８ｇ／１０分以上４０ｇ
／１０分以下，特に好ましくは２０ｇ／１０分以上３５
ｇ／１０分以下とするのがよい。In the present invention, the melt composite spinning can be performed by using a usual melt composite spinning apparatus. At the time of melt composite spinning, the copolymer component A having a melt flow rate of 5 g / 10 min to 40 g / 10 min and the copolymer component B having a melt flow rate of 15 g / 10 min to 80 g are used. / 10 minutes or less,
It is necessary to melt spin the composite staple fiber obtained by compounding both polymers so that the melt flow rate value is 15 g / 10 min or more and 45 g / 10 min or less. The melt flow rate value of this composite staple fiber is as per ASTM D1238.
It is measured by the method described in (L), and when the melt flow rate value is less than 15 g / 10 minutes,
The heat shrinkage stress of the composite staple fiber increases, and the crimping force and stretching force,
The bulkiness can be increased, but not only the spinnability of the polymer but also the heat drawability in the next step is reduced, and the spinning temperature during melt spinning is set high, causing the polypropylene polymer to decompose. It is not preferable because a large amount of gas is generated and the environment of the spinning chamber is deteriorated. On the other hand, when the melt flow rate exceeds 45 g / 10 minutes, the heat shrinkage of the conjugate short fibers is reduced, so that a nonwoven fabric having excellent stretchability and bulkiness cannot be obtained. The degree of decomposition is too low to generate a large amount of gas, which is not preferable because it deteriorates the environment of the spinning chamber. Therefore, this melt flow rate value is more than 15 g / 10 minutes and 45 g /
10 minutes or less, preferably 18 g / 10 minutes or more and 40 g
/ 10 min or less, particularly preferably 20 g / 10 min or more and 35
g / 10 minutes or less.

【００１４】溶融複合紡糸に際しては，前記重合体成分
Ａと重合体成分Ｂのメルトフローレート値比（Ｂ／Ａ）
を１／１〜６／１とする必要がある。なお，ここでいう
メルトフローレート値比とは，個別に溶融計量された重
合体を複合紡糸する前に個別に採取し，一旦冷却してチ
ツプ状にしたものを試料とし，ＡＳＴＭ Ｄ １２３８
（Ｌ）に記載の方法により測定して算出したものであ
る。本発明では，エチレンの共重合量が多い重合体成分
Ａを高収縮成分とし，このメルトフローレート値比（Ｂ
／Ａ）が１／１〜６／１すなわち重合体成分Ａを重合体
成分Ｂより高粘度とすることが重要である。重合体成分
Ａのメルトフローレート値１に対する重合体成分Ｂのメ
ルトフローレート値が１未満であると，複合短繊維の熱
収縮性が低下するので好ましくない。一方，重合体成分
Ｂのメルトフローレート値が６を超えると，両成分を用
いて溶融紡糸するに際し，紡糸口金面でニーイングが多
発して紡糸性を低下させるので好ましくない。したがっ
て，このメルトフローレート値比は，１／１〜６／１と
し，好ましくは１．２／１〜５．０／１，特に好ましく
は１．５／１〜４．０／１とするのがよい。At the time of melt composite spinning, the melt flow rate value ratio (B / A) of the polymer component A and the polymer component B is described.
Must be set to 1/1 to 6/1. The term "melt flow rate value ratio" as used herein means that the individually melt-weighed polymers are individually collected before composite spinning, and once cooled and made into a chip form as a sample, and subjected to ASTM D1238.
It is measured and calculated by the method described in (L). In the present invention, the polymer component A having a large ethylene copolymerization amount is defined as a high shrinkage component, and the melt flow rate value ratio (B
/ A) is 1/1 to 6/1, that is, it is important that the polymer component A has a higher viscosity than the polymer component B. If the melt flow rate value of the polymer component B is less than 1 with respect to the melt flow rate value 1 of the polymer component A, the heat shrinkability of the conjugate short fibers is undesirably reduced. On the other hand, when the melt flow rate value of the polymer component B exceeds 6, undesirably, kneading frequently occurs on the surface of the spinneret and spinnability decreases when melt spinning is performed using both components. Therefore, the melt flow rate value ratio is set to 1/1 to 6/1, preferably 1.2 / 1 to 5.0 / 1, and particularly preferably 1.5 / 1 to 4.0 / 1. Is good.

【００１５】また，溶融複合紡糸に際しては，前記重合
体成分Ａの溶融後のＱ値（重量平均分子量／数平均分子
量）を８以下とするのが好ましい。このＱ値とは，ゲル
パーミエイシヨンクロマトグラフ法により求められる重
合体の重量平均分子量と数平均分子量の比であり，個別
に溶融計量された重合体を複合紡糸する前に個別に採取
し，冷却した重合体を試料として測定した値である。ポ
リプロピレン重合体は溶融紡糸時に受ける熱及び剪断の
影響で劣化しやすく，溶融紡糸後のＱ値は，紡糸前のそ
れに比べ低下することが知られている。Ｑ値は分子量分
布の幅を示すものであり，複合繊維の製造適性と加工適
性に大きく影響するものである。すなわち，Ｑ値が大き
く分子量分布の幅が広いと，複合繊維に捲縮を発現させ
たり伸縮性を付与するための熱処理温度領域が広くな
り，嵩高性や伸縮性を有する不織布を安定して得ること
ができる。しかしながら，Ｑ値が大きくなって分子量分
布の幅が広くなりすぎると，溶融紡糸時の糸条冷却が悪
くなって曵糸性が低下する。したがって，このＱ値は８
以下とし，好ましくは７．５以下，特に好ましくは７．
０以下とするのがよい。In the melt-composite spinning, it is preferable that the Q value (weight average molecular weight / number average molecular weight) of the polymer component A after melting is 8 or less. The Q value is the ratio between the weight average molecular weight and the number average molecular weight of the polymer determined by gel permeation chromatography, and the individually melt-weighed polymers are individually collected before composite spinning. This is a value measured using a cooled polymer as a sample. It is known that a polypropylene polymer is easily deteriorated by the influence of heat and shear applied during melt spinning, and the Q value after melt spinning is lower than that before spinning. The Q value indicates the width of the molecular weight distribution, and greatly affects the suitability for production and processing of the conjugate fiber. That is, when the Q value is large and the molecular weight distribution is wide, the heat treatment temperature range for expressing crimp and imparting elasticity to the conjugate fiber is widened, and a nonwoven fabric having bulkiness and elasticity can be stably obtained. be able to. However, when the Q value increases and the width of the molecular weight distribution becomes too wide, the yarn cooling during melt spinning deteriorates, and the spinnability decreases. Therefore, this Q value is 8
Or less, preferably 7.5 or less, particularly preferably 7.
It is better to be 0 or less.

【００１６】また，前記重合体成分Ｂの溶融後のＱ値
（重量平均分子量／数平均分子量）を５以上８以下とす
るのが好ましい。このＱ値は，前述したように，分子量
分布の幅を示すものであり，複合繊維の製造適性と加工
適性大きく影響する。特に，重合体成分ＢのＱ値は，重
合体成分ＡのＱ値よりもさらに限定するのがよい。重合
体成分Ｂは，複合繊維の高融点成分であって捲縮発現時
の繊維モジユラスを代表するものであり，分子量分布の
幅が特に重要となる。すなわち，Ｑ値が５未満であると
重合体の分子量分布が狭くなって複合繊維の収縮率が低
下し，例えば，スタツフアボツクスを適用せずに複合繊
維に捲縮を付与するとき顕在捲縮の発現性が低下し，ウ
エブ形成に最も一般的に用いられるカード工程を良好に
通過させることが困難となったり，また，カード工程通
過後の不織ウエブあるいは不織布にエンボスローラや熱
風乾燥機等の熱処理装置を用いて熱処理を施して捲縮を
発現させたり伸縮性を付与するための熱処理温度領域が
狭くなり，嵩高性や伸縮性を有し，かつ品位の高い不織
布を安定して得ることができない。さらに，複合繊維の
タフネスが低下するため，嵩高性及び柔軟性に優れた不
織布を得ることができない。一方，Ｑ値が８を超える
と，重合体の分子量分布の幅が広くなりすぎて，溶融紡
糸時の糸条冷却が悪くなって曵糸性が低下し，細繊度の
複合繊維を得ることが困難となる。したがって，このＱ
値は５以上８以下とし，好ましくは５．３以上７．８以
下，特に好ましくは５．５以上７．５以下とするのがよ
い。The Q value (weight average molecular weight / number average molecular weight) of the polymer component B after melting is preferably 5 or more and 8 or less. As described above, this Q value indicates the width of the molecular weight distribution, and greatly affects the suitability for production and processing of the conjugate fiber. In particular, the Q value of the polymer component B is preferably further limited than the Q value of the polymer component A. The polymer component B is a high melting point component of the conjugate fiber and represents a fiber modulus at the time of crimping, and the width of the molecular weight distribution is particularly important. That is, when the Q value is less than 5, the molecular weight distribution of the polymer becomes narrow and the shrinkage of the conjugate fiber is reduced. For example, when crimping is applied to the conjugate fiber without using the stuffing box, the apparent crimp is And it becomes difficult to satisfactorily pass through the carding process most commonly used for web formation. Also, the nonwoven web or nonwoven fabric after passing through the carding process may be embossed with a roller or hot air dryer. Heat treatment using the heat treatment equipment of (1) to narrow the heat treatment temperature range for developing crimp and imparting elasticity, and to stably obtain high-quality nonwoven fabric having bulkiness and elasticity Can not. Furthermore, since the toughness of the composite fiber is reduced, a nonwoven fabric having excellent bulkiness and flexibility cannot be obtained. On the other hand, when the Q value exceeds 8, the width of the molecular weight distribution of the polymer becomes too wide, and the yarn cooling during melt spinning is deteriorated, and the spinnability is reduced. It will be difficult. Therefore, this Q
The value is 5 or more and 8 or less, preferably 5.3 or more and 7.8 or less, and particularly preferably 5.5 or more and 7.5 or less.

【００１７】さらに，溶融複合紡糸に際しては，重合体
成分Ａと重合体成分Ｂの吐出線速度を２〜10ｍ／分とす
る必要がある。ここでいう吐出線速度とは，溶融重合体
の単紡糸孔吐出量Ｑ（ｇ／分），同重合体の密度ρ（ｇ
／ｃｍ³ ）及び紡糸孔径ｄ（ｍｍ）を用い次式（ａ）に
より算出されるものである。 吐出線速度（ｍ／分）＝４Ｑ／（πρｄ² ） ・・・・・・・・・・・・・・・・・・・・（ａ） 通常，異種の重合体からなる複合繊維を溶融紡糸するに
際しては，組み合わせる重合体間のメルトフローレート
差による可紡域の差と高粘度成分により限定される溶融
温度とにより曵糸性が大きく左右され，重合体の種類に
応じて適当な吐出線速度を選択する必要がある。したが
って，本発明では，良好な曵糸性を得るために吐出線速
度を２〜10ｍ／分とすることが必要で，吐出線速度がこ
の範囲外では曵糸性が低下する。好ましくは３〜９ｍ／
分，特に好ましくは４〜８ｍ／分とするのがよい。Further, at the time of melt-composite spinning, the discharge linear speed of the polymer component A and the polymer component B needs to be 2 to 10 m / min. The discharge linear velocity here means the discharge amount Q (g / min) of the single spinning hole of the molten polymer and the density ρ (g) of the polymer.
/ Cm ³ ) and the spinning hole diameter d (mm) using the following equation (a). Discharge linear velocity (m / min) = 4Q / (πρd ² ) (a) Usually, a composite fiber composed of different polymers is melted In spinning, the spinnability is greatly affected by the difference in the spinnable range due to the difference in melt flow rate between the polymers to be combined and the melting temperature limited by the high viscosity component. You need to select a linear velocity. Therefore, in the present invention, it is necessary to set the ejection linear velocity to 2 to 10 m / min in order to obtain good spinning properties, and if the ejection linear velocity is out of this range, the spinning properties decrease. Preferably 3 to 9 m /
Min, particularly preferably 4 to 8 m / min.

【００１８】本発明では，複合繊維の複合比（Ｂ／Ａ）
（重量比）は，特に問わないが，通常，７５／２５〜２
５／７５とするのがよく，５０／５０とすると捲縮発現
性が向上するので特に好ましい。また，複合形態は，一
般的な並列構造，同心円型又は偏心円型芯鞘構造あるい
は異形断面型とするが，熱収縮性と捲縮発現性の向上を
考慮すると，並列構造とするのが望ましい。芯鞘型構造
とするときは，次式（ｂ）で定義される偏芯率を１５以
上とするのがよい。 偏芯率＝（単繊維の中心と芯成分の中心との間の距離）×１００ ／（単繊維半径）≧１５ ・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・（ｂ） 偏芯率が１５未満であると，捲縮発現性が低下し，伸縮
性と嵩高性に優れた不織布を得ることができず好ましく
ない。なお，前記両成分には，通常，繊維に用いられる
艶消し剤，耐光剤，耐熱剤あるいは顔料等を，本発明の
効果が損なわれない範囲であれば，添加することができ
る。In the present invention, the composite ratio (B / A) of the composite fiber
The (weight ratio) is not particularly limited, but is usually 75/25 to 2
The ratio is preferably 5/75, and 50/50 is particularly preferable since the crimping property is improved. In addition, although the composite form is a general parallel structure, concentric or eccentric core-sheath structure or irregular cross-sectional type, it is desirable to adopt a parallel structure in consideration of improvement in heat shrinkage and crimp development. . When the core-sheath type structure is used, the eccentricity defined by the following equation (b) is preferably set to 15 or more. Eccentricity = (distance between center of single fiber and center of core component) × 100 / (radius of single fiber) ≧ 15 (B) If the eccentricity is less than 15, crimping property is reduced, and a nonwoven fabric having excellent stretchability and bulkiness cannot be obtained, which is not preferable. In addition, a matting agent, a light-fast agent, a heat-resistant agent, a pigment or the like usually used for fibers can be added to both components as long as the effects of the present invention are not impaired.

【００１９】本発明では，次に，溶融複合紡糸して得ら
れた前記未延伸複合繊維を５０℃以上かつ繊維相互が融
着しない温度で熱延伸する。熱延伸は，通常の熱延伸装
置を用いて行うことができる。通常，熱可塑性合成繊維
を延伸する場合，ガラス転移温度以上で加熱延伸をする
ことが知られているが，本発明ではガラス転移温度より
相当高い５０℃以上の温度で熱延伸をする。延伸温度が
５０℃未満であると，延伸張力が高くなりすぎて延伸性
が低下し，また，延伸装置が設備的に高くなるので好ま
しくない。また，本発明では，延伸温度は高くとも繊維
相互が融着し始める温度未満とする。延伸温度が高くな
りすぎて繊維相互が融着し始めると，延伸工程で糸切れ
が発生して操業性が低下したり，製品の均一性が低下す
ることによって品位が低下したりするので好ましくな
い。したがって，この延伸温度は，５０℃以上かつ繊維
相互が融着しない温度とし，好ましくは７０〜１２０℃
とするのがよい。Next, in the present invention, the undrawn composite fiber obtained by melt-spinning is hot-drawn at a temperature of 50 ° C. or more and at a temperature at which the fibers do not fuse with each other. The hot stretching can be performed using a normal hot stretching apparatus. In general, it is known that, when a thermoplastic synthetic fiber is drawn, heat drawing is performed at a temperature higher than the glass transition temperature, but in the present invention, the heat drawing is performed at a temperature of 50 ° C. or higher, which is considerably higher than the glass transition temperature. If the stretching temperature is lower than 50 ° C., the stretching tension becomes too high and the stretching property is lowered, and the stretching apparatus is undesirably increased in equipment. Further, in the present invention, the drawing temperature is lower than the temperature at which the fibers start to fuse with each other at the highest. If the drawing temperature is too high and the fibers start to fuse with each other, yarn breakage will occur in the drawing process and the operability will decrease, or the quality of the product will decrease due to the lower uniformity of the product, which is not preferable. . Therefore, the stretching temperature is set to a temperature of 50 ° C. or higher and a temperature at which the fibers are not fused to each other, and preferably 70 to 120 ° C.
It is good to do.

【００２０】次いで，得られた延伸複合繊維に捲縮付与
処理を施す。捲縮付与処理は，通常のスタツフア型捲縮
付与装置等の捲縮付与装置を用いて行うことができる。
この捲縮付与処理に引き続き，繊維に仕上げ油剤を付与
し，乾燥した後，所定長さに切断して短繊維とする。Next, the obtained drawn composite fiber is subjected to a crimping treatment. The crimping treatment can be performed by using a crimping device such as a usual staff type crimping device.
Subsequent to the crimping treatment, the fiber is applied with a finishing oil, dried, and then cut into a predetermined length to obtain short fibers.

【００２１】本発明では，複合短繊維の単繊維繊度を６
デニール以下とするのがよい。単繊維繊度が６デニール
を超えると，不織布としたとき柔軟性が低下したり，あ
るいは溶融紡糸に際し，ポリプロピレン系溶融重合体の
冷却が不十分となりフイラメント間に融着が生じて曵糸
性が低下したりするため好ましくない。In the present invention, the single fiber fineness of the conjugate short fibers is set to 6
It should be less than denier. If the single-fiber fineness exceeds 6 denier, the flexibility of the nonwoven fabric decreases, or the melt of the polypropylene-based molten polymer is insufficiently cooled during melt spinning, causing fusion between filaments and lowering spinnability. Is not preferred.

【００２２】本発明の方法で得られる複合短繊維は，温
度１２０℃及び初荷重２ｍｇ条件において３５％以上の
乾熱収縮率を，かつ温度１２０℃での熱処理で捲縮数が
６０個／２５ｍｍ以上の捲縮を発現するものである。複
合短繊維の乾熱収縮率は，繊維自身の増径と捲縮形態へ
の変換力により伸縮力に寄与するものであり，また，熱
処理後の捲縮数は，未処理繊維の捲縮数の増加分が伸縮
性と嵩高性に寄与するものであり，乾熱収縮率と熱処理
後の捲縮数は，共に高いほど大きな伸縮性と嵩高性を発
現する。この乾熱収縮率は，温度１２０℃及び初荷重２
ｍｇの条件で測定されるものであって，本発明の方法で
得られる複合短繊維は，上記温度及び荷重条件で３５％
以上の乾熱収縮率を発現し，かつ上記温度での熱処理で
捲縮数が６０個／２５ｍｍ以上の捲縮を発現し，伸縮性
と嵩高性に優れた不織布を得ることができるのである。
前記乾熱収縮率が３５％未満，かつ前記熱処理後の捲縮
数が６０個／２５ｍｍ未満であると，伸縮性と嵩高性に
優れた不織布を得ることができず好ましくない。なお，
本発明の方法で得られる複合短繊維では，温度１２０℃
及び初荷重５０ｍｇの条件で測定される乾熱収縮率が３
０％以上であると，高伸長応力下においても高度の収縮
性が発現し，繊維に瞬時の回復性が発現するため，さら
に好ましい。The composite staple fiber obtained by the method of the present invention has a dry heat shrinkage of 35% or more at a temperature of 120 ° C. and an initial load of 2 mg, and has a number of crimps of 60/25 mm by heat treatment at a temperature of 120 ° C. It exhibits the above crimp. The dry heat shrinkage of the conjugate staple fiber contributes to the expansion and contraction force by increasing the diameter of the fiber itself and converting to a crimped form, and the number of crimps after heat treatment is the number of crimps of the untreated fiber. The increased amount contributes to elasticity and bulkiness, and the higher the dry heat shrinkage and the number of crimps after heat treatment, the higher the elasticity and bulkiness. This dry heat shrinkage rate is 120 ° C and initial load 2
mg of the composite staple fiber obtained by the method of the present invention.
The dry heat shrinkage ratio described above is exhibited, and the number of crimps is 60/25 mm or more by heat treatment at the above-mentioned temperature, whereby a nonwoven fabric excellent in stretchability and bulkiness can be obtained.
If the dry heat shrinkage is less than 35% and the number of crimps after the heat treatment is less than 60/25 mm, it is not preferable because a nonwoven fabric having excellent stretchability and bulkiness cannot be obtained. In addition,
The composite staple fiber obtained by the method of the present invention has a temperature of 120 ° C.
And the dry heat shrinkage measured under the condition of initial load of 50 mg is 3
When the content is 0% or more, a high degree of shrinkage is exhibited even under a high elongation stress, and instantaneous recoverability is exhibited in the fiber.

【００２３】本発明の方法で得られる複合短繊維は，３
ｇ／デニール以上の強度を有するものであり，複合短繊
維を用いて不織布を作成し，得られた不織布を特におむ
つ等の医療衛生材用素材に用いたとき原綿が脱落し肌に
付着して違和感を生じたり，おむつ内外へ繊維吸収体が
露出する等の問題を生じたりすることがない。また，サ
ポータとして用いたときには，膝抜け現象が生じたり，
破損したりすることがない。The composite staple fiber obtained by the method of the present invention comprises 3
g / denier or more, and when a nonwoven fabric is made using composite staple fibers and the resulting nonwoven fabric is used for medical hygiene materials, especially diapers, the raw cotton falls off and adheres to the skin. It does not cause any discomfort or problems such as exposure of the fiber absorber inside and outside the diaper. In addition, when used as a supporter, knee dropout may occur,
There is no damage.

【００２４】本発明の方法で得られる複合短繊維は，熱
処理前の複合短繊維の共重合体成分Ａ部分の複屈折と共
重合体成分Ｂ部分の複屈折が共に０．０２以上であり，
かつ熱処理後の複合短繊維の共重合体成分Ａ部分の複屈
折と共重合体成分Ｂ部分の複屈折が共に上記熱処理前の
複合短繊維の共重合体成分Ａ部分の複屈折と共重合体成
分Ｂ部分の複屈折よりそれぞれ低いものである。この複
屈折は，カールツアイス イエナ干渉顕微鏡を用い，封
入剤として流動パラフインとα−ブロムナフタリン混合
液を用いて処理を行い，得られた複合繊維を試料として
重合体成分Ａと重合体成分Ｂの複屈折をそれぞれ測定し
たものである。複屈折は繊維の配向性を表す指標として
一般的に用いられるものである。複合繊維はある一定の
配向を有し，繊維に熱処理を施すと熱収縮が極めて大き
くなるが，このとき配向は一挙に緩和して複屈折が低下
する。このことは，実質的な収縮が繊維の構造変化をも
たらすことを意味しており，この熱収縮により大きな伸
縮性を発現する繊維構造を得ることができる。複屈折が
低いと，繊維の配向性が低いため熱処理を施しても熱収
縮が大きくならず，このため大きな伸縮性を発現する繊
維構造を得ることができず好ましくない。The conjugate short fiber obtained by the method of the present invention has a birefringence of the copolymer component A portion and the birefringence of the copolymer component B portion of both conjugate short fibers before heat treatment of 0.02 or more.
The birefringence of the copolymer component A portion and the birefringence of the copolymer component B portion of the conjugate short fiber after the heat treatment are both the birefringence of the copolymer component A portion of the conjugate short fiber before the heat treatment and the copolymer. It is lower than the birefringence of the component B portion. The birefringence was measured using a Carl Zeiss Jena interference microscope, using liquid paraffin and α-bromonaphthalene mixture as an encapsulant, and using the resulting composite fiber as a sample, polymer components A and B. The birefringence was measured. The birefringence is generally used as an index indicating the orientation of the fiber. The conjugate fiber has a certain orientation, and when the fiber is subjected to a heat treatment, the heat shrinkage becomes extremely large. At this time, the orientation is relaxed at once, and the birefringence decreases. This means that the substantial shrinkage causes a structural change of the fiber, and a fiber structure exhibiting great elasticity can be obtained by this heat shrinkage. When the birefringence is low, the heat shrinkage does not increase even if heat treatment is performed because the orientation of the fiber is low, so that a fiber structure exhibiting a large elasticity cannot be obtained, which is not preferable.

【００２５】本発明の方法で得られる複合短繊維は，広
角Ｘ線回折法により測定される熱処理前の複合短繊維の
結晶体積が１０００００ų 以下であり，かつ広角Ｘ線
回折法により測定される熱処理後の複合短繊維の結晶体
積が２０００００ų 以上のものである。この結晶体積
は広角Ｘ線回折法により求められるものであって，α型
単位胞（ａ＝６．６５Å，ｂ＝２０．９６Å，ｃ＝６．
５０Å，β＝９９．２°）のａ軸方向，ｂ軸方向及びｃ
軸方向に相当する各結晶面Ｌ（１１０），Ｌ（１３０）
及びＬ（００３）の面間隔を用い次のＳｃｈｅｒｒｅｒ
の式（ｃ）により見掛けの結晶サイズＬ（ｈｋｌ）を求
め，それらの結晶サイズの積から算出されるものであ
る。 結晶サイズ〔Ｌ（ｈｋｌ）〕＝Ｋλ／βｃｏｓθ ・・・・・・・・・・・・・・・・（ｃ） Ｋ＝０．９，λ＝１．５４１８， β＝［〔各結晶面の半価幅（ｄｅｇ）〕² −０．６７² ］^1/2 熱処理前の繊維の結晶体積が１０００００ų を超える
と，結晶体積が大き過ぎるため繊維に熱処理を施しても
結晶の成長が望めず，したがって熱収縮が大きくならな
いため大きな伸縮性を発現する繊維構造を得ることがで
きず好ましくない。一方，熱処理後の繊維の結晶体積が
２０００００ų 未満であると，結晶体積が十分に大き
くないため安定な繊維構造を得ることができず好ましく
ない。The composite short fibers obtained by the process of the present invention is measured crystal volume of composite short fibers before the heat treatment as measured by wide angle X-ray diffraction method is at 100000 ³ or less, and the wide-angle X-ray diffraction method crystal volume of composite short fibers after the heat treatment is of the 200000A ³ or more. This crystal volume is determined by the wide-angle X-ray diffraction method and is based on α-type unit cells (a = 6.65 °, b = 20.96 °, c = 6.
50 °, β = 99.2 °) a-axis direction, b-axis direction and c
Each crystal plane L (110), L (130) corresponding to the axial direction
And the following Scherrer using the plane spacing of L (003)
The apparent crystal size L (hkl) is obtained by the equation (c), and is calculated from the product of those crystal sizes. Crystal size [L (hkl)] = Kλ / βcos θ (c) K = 0.9, λ = 1.5418, β = [[Each crystal face When the half width (deg)] ² -0.67 ^{2] 1/2} heat treatment crystal volume before the fiber exceeds 100000 ^3, also views of the crystal growth by heat treatment to the fiber for crystal volume is too large Therefore, since the heat shrinkage does not increase, a fiber structure exhibiting a large elasticity cannot be obtained, which is not preferable. On the other hand, when the crystal volume of the fiber after the heat treatment is less than 200000A ^3, it can not be obtained a stable fiber structure is not preferable since the crystal volume is not large enough.

【００２６】本発明の方法で得られる複合短繊維は，小
角Ｘ線散乱法により測定される熱処理前の複合短繊維の
長周期が１３０Å未満であり，かつ小角Ｘ線散乱法によ
り測定される熱処理後の複合短繊維の長周期が１３０Å
以上のものである。この長周期は広角Ｘ線回折法により
求められるものであって，重合体成分Ａと重合体成分Ｂ
が接合された状態での結晶部と非晶部との和の平均的な
長さを示すものである。この複合短繊維では，熱処理前
の複合短繊維の長周期が１３０Å未満で，適度な結晶部
と適度な非晶部とが混在した状態にある。熱処理前の複
合短繊維の長周期が１３０Å以上で繊維の結晶部がすで
に大きく成長しているとき繊維が構造緩和した状態に近
づいているため熱収縮率が大きくならず，したがって大
きな伸縮性を発現する繊維構造を得ることができず好ま
しくない。また，繊維の非晶部が大きいとき熱収縮率は
大きくなるが，経時安定性が劣るため好ましくない。し
たがって，熱処理前の複合短繊維は，適度な結晶部と適
度な非晶部とが混在した状態であって，長周期が１３０
Å未満であることが好ましい。熱処理前の長周期が抑制
された状態にあることによって，熱処理後の繊維の分子
鎖的構造緩和を助長し，熱収縮をより大きくすることが
できるのである。さらに，この複合短繊維では，熱処理
後の複合短繊維の長周期が１３０Å以上であることが好
ましい。熱処理により，非晶部の結晶部への組み込みに
より結晶が分子鎖軸方向に成長して長周期が１３０Å以
上となることにより，安定な構造を得ることができるの
である。なお，ここでいう熱処理とは，複合短繊維を
（重合体成分Ｂの融点−４０℃）以上重合体成分Ｂの融
点未満の温度で自由長処理するものをいう。The short conjugate fiber obtained by the method of the present invention has a long cycle of less than 130 ° before the heat treatment as measured by the small-angle X-ray scattering method and the heat treatment measured by the small-angle X-ray scattering method. The long cycle of the composite short fiber is 130Å
That's all. This long period is determined by the wide-angle X-ray diffraction method, and the polymer component A and the polymer component B
Indicates the average length of the sum of the crystal part and the amorphous part in a state where the two are joined. In this composite staple fiber, the long cycle of the composite staple fiber before the heat treatment is less than 130 °, and a suitable crystal part and a suitable amorphous part are mixed. When the long cycle of the conjugate short fiber before heat treatment is 130 ° or more and the crystal part of the fiber has already grown large, the fiber is approaching a state where the structure is relaxed, so the heat shrinkage does not increase, and therefore, large elasticity is exhibited. It is not preferable because a fibrous structure cannot be obtained. Further, when the amorphous portion of the fiber is large, the heat shrinkage increases, but this is not preferable because the stability over time is poor. Therefore, the conjugate short fibers before heat treatment are in a state in which a suitable crystal part and a suitable amorphous part are mixed, and have a long period of 130.
It is preferably less than Å. When the long cycle before the heat treatment is suppressed, the relaxation of the molecular structure of the fiber after the heat treatment is promoted, and the heat shrinkage can be further increased. Further, in this composite short fiber, it is preferable that the long cycle of the composite short fiber after the heat treatment is 130 ° or more. By the heat treatment, the crystal grows in the direction of the molecular chain axis due to the incorporation of the amorphous part into the crystal part, and the long period becomes 130 ° or more, so that a stable structure can be obtained. Here, the heat treatment refers to a treatment in which the conjugate short fibers are subjected to free length treatment at a temperature of (the melting point of the polymer component B −40 ° C.) or more and less than the melting point of the polymer component B.

【００２７】本発明の方法で得られる複合短繊維は，密
度法により測定される熱処理前の複合短繊維の結晶化度
が７０％未満であり，かつ密度法により測定される熱処
理後の複合短繊維の結晶化度が７０％以上のものであ
る。この結晶化度は密度法により測定されるものであっ
て，次式（ｄ）から算出される。 結晶化度＝（ρｃ／ρ）×〔（ρ−ρａ）／（ρｃ−ρａ）〕 ×１００ ・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・（ｄ） ρｃは結晶密度，ρａは非晶密度，ρは試料の密度測定
値 ρｃ＝０．９３６０ｇ／ｃｍ³ ，ρａ＝０．８５４５ｇ
／ｃｍ³ この複合短繊維に熱処理を施して結晶化度を向上させる
ことにより，この繊維を用いて最終製品としたとき耐熱
性が向上した製品を得ることができる。The conjugate short fibers obtained by the method of the present invention have a crystallinity of less than 70% before the heat treatment as measured by the density method, and the conjugate short fibers after the heat treatment as measured by the density method. The fiber has a crystallinity of 70% or more. This crystallinity is measured by the density method and is calculated from the following equation (d). Crystallinity = (ρc / ρ) × [(ρ−ρa) / (ρc−ρa)] × 100 (D) ρc is the crystal density, ρa is the amorphous density, ρ is the measured density of the sample, ρc = 0.9360 g / cm ³ , ρa = 0 .8545 g
/ Cm ³ by increasing the composite short fiber is subjected to a heat treatment crystallinity, it is possible to obtain a product heat resistance is improved when a final product using the fiber.

【００２８】次に，本発明の不織布の製造方法に関して
説明する。本発明の方法では，まず，前記複合短繊維を
用いてウエブを作成する。まず，前記複合短繊維を単独
で，あるいは前記複合短繊維５０重量％以上と他素材の
短繊維５０重量％以下とを混綿し，カード機によりカー
デイングして所定目付けのウエブを作成する。前記複合
短繊維と混綿する他素材の短繊維としては通常の熱可塑
性合成短繊維あるいはコツトン等の天然繊維を用いるこ
とができる。このウエブは，構成繊維の配列度合によっ
て，カード機の進行方向に配列したパラレルウエブ，ラ
ンダムに配列したランダムウエブ，あるいは両者の中程
度に配列したセミランダムウエブのいずれであってもよ
い。なお，前記複合短繊維のカードウエブと他素材のカ
ードウエブを重ねた積層ウエブとしてもよい。本発明で
は，不織布の構成繊維の５０重量％以上を前記複合短繊
維とするため，伸縮性と嵩高性に優れた不織布を得るこ
とができる。Next, the method for producing the nonwoven fabric of the present invention will be described. In the method of the present invention, first, a web is prepared using the composite short fibers. First, the composite staple fiber alone or a mixture of 50% by weight or more of the composite staple fiber and 50% by weight or less of another material short fiber is carded by a card machine to prepare a web having a predetermined basis weight. As the short fibers of the other material mixed with the conjugate short fibers, ordinary thermoplastic synthetic short fibers or natural fibers such as cotton can be used. This web may be any of a parallel web arranged in the traveling direction of the card machine, a random web arranged at random, or a semi-random web arranged at an intermediate level depending on the arrangement degree of the constituent fibers. The card web of the composite short fiber and the card web of another material may be a laminated web. In the present invention, 50% by weight or more of the constituent fibers of the nonwoven fabric is the conjugate short fiber, so that a nonwoven fabric excellent in stretchability and bulkiness can be obtained.

【００２９】次に，得られたカードウエブを多孔性支持
部材上に載置した後，圧力が３０ｋｇ／ｃｍ² 未満の流
体噴流により前記ウエブに流体絡合処理を施した後，圧
力が５０ｋｇ／ｃｍ² 以上の流体噴流により前記ウエブ
に流体絡合処理を施してウエブを構成する前記複合短繊
維相互を三次元的に絡合させる。本発明でいう流体絡合
処理とは，孔径が０．０５〜１．０ｍｍのオリフイスを
オリフイス間距離０．５〜１０ｍｍで１列又は複数列に
複数個配設し，これらのオリフイスから高圧で柱状に噴
出される流体噴流によりウエブの構成繊維同士を絡合さ
せるものである。流体としては，常温の水あるいは熱水
を使用することができる。また，添加剤を混入した水を
使用することもできる。流体噴流を前記ウエブに衝突さ
せるに際しては，前記オリフイスが１列又は複数列に複
数個配設されたオリフイスヘツドを，多孔性支持部材上
に積層載置された前記ウエブの進行方向と直角の方向
に，オリフイス間距離と同一距離の振幅で往復運動さ
せ，柱状流体噴流を均一に衝突させるとよい。この流体
絡合処理は，少なくとも２回に分けて施すとよい。第１
回目の流体絡合処理は，圧力が３０ｋｇ／ｃｍ² 未満の
流体噴流を使用し，同圧力の流体噴流を前記ウエブに衝
突させることにより，ウエブの構成繊維相互を予備絡合
させるものである。この圧力が３０ｋｇ／ｃｍ² 以上で
あると，ウエブの構成繊維相互が絡合されず，しかも構
成繊維が水流により乱れてしまい，ウエブに目付け斑が
生じるので好ましくない。次いで，第２回目の流体絡合
処理を施す。第２回目の流体絡合処理は，圧力が５０ｋ
ｇ／ｃｍ² 以上の流体噴流を使用し，同圧力の流体噴流
を前記ウエブに衝突させることにより，第１回目の流体
絡合処理によりウエブに形成された構成繊維相互の予備
絡合をより強固なものにするためのものである。この第
２回目の処理では，圧力を５０ｋｇ／ｃｍ² 以上とする
のが好ましく，圧力が５０ｋｇ／ｃｍ² 未満であると，
構成繊維同士の絡合がより強固なものにならず，不織布
として使用するに際し十分な強力を得ることができな
い。なお，さらに強固な絡合を必要とする場合には，前
記第２回目の流体絡合処理を，同一条件で複数回施すと
よい。前記ウエブが載置される多孔性支持部材として
は，ウエブを通過した流体噴流が抵抗なく除去されるも
のであればいかなるものであってもよいが，特に，金網
や合成繊維織物等からなる２００メツシユ以下の多孔性
部材が好ましい。Next, after placing the obtained card web on a porous support member, the web is subjected to a fluid entanglement treatment by a fluid jet having a pressure of less than 30 kg / cm ² , and then the pressure is reduced to 50 kg / cm ^2. The web is subjected to a fluid entanglement treatment by a fluid jet of cm ² or more to three-dimensionally entangle the composite short fibers constituting the web. In the fluid entanglement treatment according to the present invention, a plurality of orifices having a hole diameter of 0.05 to 1.0 mm are arranged in one or a plurality of rows at a distance between orifices of 0.5 to 10 mm, and high pressure is applied from these orifices. The constituent fibers of the web are entangled with each other by a fluid jet jetted in a columnar shape. Water at normal temperature or hot water can be used as the fluid. Also, water mixed with additives can be used. When the fluid jet collides with the web, the orifice head in which a plurality of orifices are arranged in one or more rows is placed in a direction perpendicular to the traveling direction of the web stacked and mounted on a porous support member. Then, the columnar fluid jet is preferably made to reciprocate with the same amplitude as the distance between the orifices so as to uniformly collide. This fluid entanglement process may be performed at least twice. First
The first fluid entanglement process uses a fluid jet having a pressure of less than 30 kg / cm ^2, and impinges the fluid jet at the same pressure on the web to pre-interlace the constituent fibers of the web with each other. If the pressure is 30 kg / cm ² or more, the constituent fibers of the web are not entangled with each other, and furthermore, the constituent fibers are disturbed by the water flow, and the web is not uniformly spotted. Next, a second fluid entanglement process is performed. In the second fluid entanglement process, the pressure is 50k
g / cm ² or more, and by impinging a fluid jet at the same pressure on the web, the pre-entanglement between the constituent fibers formed on the web by the first fluid entanglement process is further strengthened. It is to make something. In the second treatment, the pressure is preferably 50 kg / cm ² or more, and if the pressure is less than 50 kg / cm ² ,
The entanglement of the constituent fibers does not become stronger, and sufficient strength cannot be obtained when used as a nonwoven fabric. If a stronger entanglement is required, the second fluid entanglement process may be performed a plurality of times under the same conditions. As the porous support member on which the web is placed, any porous support member may be used as long as the fluid jet flowing through the web can be removed without resistance. In particular, the porous support member may be made of wire mesh, synthetic fiber fabric, or the like. A porous member having a mesh or less is preferable.

【００３０】次に，前記流体絡合処理に引き続き，ウエ
ブ中に残存する水分を乾燥除去した後，熱風循環式乾燥
機等の乾燥装置を用いて乾熱処理を施すことにより，ウ
エブの構成繊維に捲縮を発現させる。この捲縮は，温度
１２０℃で熱処理したとき捲縮数が６０個／２５ｍｍ以
上のものであり，これにより不織布に伸縮性と嵩高性が
付与される。本発明の方法では，ウエブに，ウエブ中に
残存する水を乾燥除去した後，熱カレンダあるいは熱エ
ンボスローラにより乾熱処理を施すこともできる。本発
明の方法は，前記複合短繊維からなるウエブに他の素
材，例えば，コツトンのカードウエブを重ねた積層ウエ
ブに流体絡合処理を施すことも含むものである。Next, following the fluid entanglement treatment, moisture remaining in the web is dried and removed, and then subjected to a dry heat treatment using a drying device such as a hot air circulation type drier, so that the fibers constituting the web are treated. Develop crimps. This crimp has a number of crimps of 60 pieces / 25 mm or more when heat-treated at a temperature of 120 ° C., thereby imparting elasticity and bulkiness to the nonwoven fabric. In the method of the present invention, the web may be subjected to dry heat treatment using a hot calendar or a hot embossing roller after water remaining in the web is removed by drying. The method of the present invention also includes subjecting the web made of the composite staple fibers to a fluid entanglement treatment on a laminated web in which another material, for example, a cotton card web is stacked.

【００３１】本発明の方法で得られる不織布は，不織布
を構成する前記複合短繊維相互が三次元的に絡合してい
るため不織布として使用するに際し実用上十分な強力が
発現する。また，温度１２０℃及び初荷重２ｍｇ条件に
おける乾熱収縮率が３５％以上となる高収縮力と，温度
１２０℃で熱処理後の捲縮数が６０個／２５ｍｍ以上と
なる高捲縮力とを有する前記複合短繊維から構成される
ため，伸縮性と嵩高性に優れるともとに見掛け密度が
０．１０ｇ／ｃｍ³ 以下と低密度のものとなる。さら
に，不織布の引張強力測定における２０％及び５０％伸
長時の伸長弾性率が縦横方向共４０％以上であり，縦横
方向共に伸縮性に優れ，しかもこの高モジユラスにより
形態安定性が優れ，不織布を特に医療衛生材用素材とし
て使用したとき型崩れを生じたりすることがない。な
お，本発明では，不織布の目付けは，その用途上の要求
特性からして，１０ｇ／ｍ² 以上１５０ｇ／ｍ² 以下と
するのがよい。The nonwoven fabric obtained by the method of the present invention exhibits practically sufficient strength when used as a nonwoven fabric because the composite short fibers constituting the nonwoven fabric are three-dimensionally entangled with each other. In addition, a high shrinkage force at which the dry heat shrinkage rate at a temperature of 120 ° C. and an initial load of 2 mg is 35% or more, and a high crimping force at a temperature of 120 ° C. at which the number of crimps after heat treatment is 60 pieces / 25 mm or more. Since it is composed of the above-mentioned conjugate short fibers, the apparent density is 0.10 g / cm ³ or less and the density is low as well as excellent in elasticity and bulkiness. Furthermore, the elongation modulus at 20% and 50% elongation in the tensile strength measurement of the nonwoven fabric is 40% or more in both the longitudinal and transverse directions, and the stretchability in both the longitudinal and transverse directions is excellent. In particular, when used as a material for medical hygiene materials, it does not lose its shape. In the present invention, the basis weight of the nonwoven fabric is preferably 10 g / m ² or more and 150 g / m ² or less in view of the required characteristics of the application.

【００３２】[0032]

【実施例】次に，実施例に基づいて本発明を具体的に説
明する。なお，実施例における各種特性の測定及び評価
は，次の方法により実施した。 重合体の融点：パーキンエルマ社製示差走査型熱量計Ｄ
ＳＣ−２型を用い，昇温速度２０℃／分で測定した融解
吸収熱曲線の極値を与える温度を融点とした。 メルトフローレート値：ＡＳＴＭ Ｄ １２３８（Ｌ)
に記載の方法により測定した。 繊維の引張強伸度：東洋ボールドウイン社製テンシロン
ＵＴＭ−４−１−１００を用い，試料長２０ｍｍの試料
を引張速度２０ｍｍ／分で測定した。 繊維の乾熱収縮率Ｉ：単繊維計１５本を試料とし，各単
繊維ごとに初荷重２ｍｇ／デニール時の長さＬ₁ （ｃ
ｍ）を測定し，次いでエアーオーブン型熱処理機中で１
２０℃×１５分間熱処理した後の長さＬ₂ （ｃｍ）を測
定し，次式（ｅ）により収縮率を算出し，その平均値を
乾熱収縮率Ｉとした。 乾熱収縮率Ｉ（％）＝（Ｌ₁ −Ｌ₂ ）×１００／Ｌ₁ ・・・・・・・・・・・・（ｅ） 繊維の乾熱収縮率II：単繊維計１５本を試料とし，各単
繊維ごとに初荷重５０ｍｇ／デニール時の長さＬ₃ （ｃ
ｍ）を測定し，次いでエアーオーブン型熱処理機中で１
２０℃×１５分間熱処理した後の長さＬ₄ （ｃｍ）を測
定し，次式（ｆ）により収縮率を算出し，その平均値を
乾熱収縮率IIとした。 乾熱収縮率II（％）＝（Ｌ₃ −Ｌ₄ ）×１００／Ｌ₃ ・・・・・・・・・・・・（ｆ） 不織布の引張強伸度：東洋ボールドウイン社製テンシロ
ンＵＴＭ−４−１−１００を用い，ＪＩＳ Ｌ−１０９
６Ａに記載のストリツプ法にしたがい，試料幅２．５ｃ
ｍ，試料長１０ｃｍの試料片を引張速度１０ｃｍ／分で
測定した。 不織布の伸長弾性率：東洋ボールドウイン社製テンシロ
ンＵＴＭ−４−１−１００を用い，ＪＩＳ Ｌ−１０９
６ ６．１３．１Ａに記載の方法にしたがい，試料幅
２．５ｃｍ，試料長１０ｃｍの試料片を引張速度１０ｃ
ｍ／分で引張試験を実施し，伸度が２０％時点又は５０
％時点の一定伸びに対する回復伸びの比率から求めた。 不織布の見掛け密度：試料幅１０ｃｍ，試料長１０ｃｍ
の試料片を計５個準備し，各試料片ごとに目付け（ｇ／
ｍ² ）を測定した後，大栄科学精器製作所製厚さ測定器
を用いて，４．５ｇ／ｃｍ² の荷重を印加し１０秒放置
した後の厚さ（ｍｍ）を測定し，次式（ｇ）により見掛
け密度を算出し，その平均値を不織布の見掛け密度とし
た。 見掛け密度（ｇ／ｃｍ³ ）＝（目付け）×10^-3／（厚さ） ・・・・・・・・（ｇ） ニーイング：溶融紡糸時の紡糸孔部におけるニーイング
の発生を次の２段階で評価した。○：ニーイングの角度
が７５°未満で，操業上問題とならない。×：ニーイン
グの角度が７５°以上と大きく，操業上問題である。 発煙性：溶融紡糸時の紡糸口金部での発煙度合いを視覚
判定により次の４段階で評価した。◎：発煙が全く観察
されない。○：発煙がやや観察される。△：発煙が相当
観察されるが，操業上問題とならない。×：発煙が極め
て多く，発煙物が紡糸口金付近に堆積し，操業上問題で
ある。 曵糸性：溶融紡糸時の曵糸性を糸切れの発生率により次
の３段階で評価した。○：糸切れが全く発生せず，操業
性が良好である。△：糸切れが２４時間・紡糸錘数１６
当たり１回発生。×：糸切れが２４時間・紡糸錘数１６
当たり２回以上発生し，操業上問題である。 延伸性：延伸性を糸切れ及び単糸切れの発生率により次
の３段階で評価した。○：糸切れや単糸切れが全く発生
せず，操業性が良好である。△：糸切れや単糸切れが２
４時間当たり１回発生。×：糸切れや単糸切れが２４時
間当たり２回以上発生し，操業上問題である。Next, the present invention will be specifically described based on examples. The measurement and evaluation of various characteristics in the examples were performed by the following methods. Melting point of polymer: Differential scanning calorimeter D manufactured by PerkinElmer
The melting point was defined as the temperature at which an extreme value of the melting heat absorption curve measured at a heating rate of 20 ° C./min using SC-2 type. Melt flow rate value: ASTM D 1238 (L)
Was measured according to the method described in Tensile strength and elongation of fiber: A sample having a sample length of 20 mm was measured at a tensile speed of 20 mm / min using Tensilon UTM-4-1-100 manufactured by Toyo Baldwin. Dry heat shrinkage ratio I of fibers: A total of 15 single fibers were used as samples, and the length L ₁ (c) of the initial load of 2 mg / denier was used for each single fiber.
m) and then measure 1 in an air oven type heat treatment machine.
The length L ₂ (cm) after the heat treatment at 20 ° C. × 15 minutes was measured, the shrinkage was calculated by the following equation (e), and the average value was defined as dry heat shrinkage I. Dry heat shrinkage I (%) = (L ₁ −L ₂ ) × 100 / L ₁ (e) Fiber dry heat shrinkage II: 15 single fibers in total As a sample, length L ₃ (c) at initial load of 50 mg / denier for each single fiber
m) and then measure 1 in an air oven type heat treatment machine.
The length L ₄ (cm) after the heat treatment at 20 ° C. for 15 minutes was measured, the shrinkage was calculated by the following equation (f), and the average was defined as dry heat shrinkage II. Dry heat shrinkage II (%) = (L ₃ −L ₄ ) × 100 / L ₃ (f) Tensile strength and elongation of nonwoven fabric: Tensilon UTM manufactured by Toyo Baldwin Co., Ltd. −4-1-100 and JIS L-109
According to the stripping method described in 6A, sample width 2.5c
m, a sample piece having a sample length of 10 cm was measured at a tensile speed of 10 cm / min. Elongation modulus of nonwoven fabric: JIS L-109 using Tensilon UTM-4-1-100 manufactured by Toyo Baldwin Co., Ltd.
6 In accordance with the method described in 6.13.1A, a sample piece having a sample width of 2.5 cm and a sample length of 10 cm was pulled at a tensile speed of 10 c.
A tensile test was conducted at a rate of 20% / m / min.
The percentage was calculated from the ratio of the recovery growth to the constant growth at%. Apparent density of non-woven fabric: sample width 10 cm, sample length 10 cm
A total of five sample pieces were prepared, and the basis weight (g /
m ² ), the thickness (mm) after applying a load of 4.5 g / cm ² and allowing to stand for 10 seconds using a thickness measuring device manufactured by Daiei Kagaku Seiki Seisakusho, The apparent density was calculated according to (g), and the average value was defined as the apparent density of the nonwoven fabric. Apparent density (g / cm ³ ) = (basis weight) × 10 ⁻³ / (thickness) (k) Kneeing: The generation of kneeing in the spinning hole during melt spinning is performed in the following two stages. Was evaluated. ：: The kneeing angle was less than 75 °, and no problem occurred in operation. ×: The kneeing angle is as large as 75 ° or more, which is a problem in operation. Smoke emission: The degree of smoke emission at the spinneret during melt spinning was evaluated by visual judgment in the following four stages. A: No smoke is observed. ：: Smoke is slightly observed. Δ: Smoke is considerably observed, but there is no problem in operation. ×: Smoke is extremely large, and smoke is deposited near the spinneret, which is a problem in operation. Spinnability: The spinnability at the time of melt spinning was evaluated by the following three stages based on the incidence of yarn breakage. ：: No breakage of yarn at all and good operability. △: Twenty-four hours of yarn breakage, 16 spindles
Occurs once per time. ×: Twenty-four hours of thread breakage and 16 spindles
Occurs twice or more per operation, which is an operational problem. Stretchability: The stretchability was evaluated in the following three stages based on the incidence of yarn breakage and single yarn breakage. ：: No breakage of single yarn and no breakage of single yarn occurred, and operability was good. △: 2 broken yarns or broken single yarns
Occurs once every 4 hours. X: Thread breakage or single yarn breakage occurs twice or more per 24 hours, which is a problem in operation.

【００３３】実施例１〜１１及び比較例１〜９ 表１に示したＱ値とメルトフローレート値，融点を有
し，プロピレンとエチレンがランダム共重合されたポリ
プロピレン系共重合体を成分Ａとし，表１に示したＱ値
とメルトフローレート値，融点を有するポリプロピレン
重合体あるいはプロピレンとエチレンがランダム共重合
又はブロツク共重合されたポリプロピレン系共重合体を
成分Ｂとし，通常のエクストルーダ型溶融押出機で溶融
した後，紡糸孔径が０．５ｍｍ，孔数が３００の紡糸口
金を用い，単孔吐出量を各々０．５ｇ／分すなわち成分
Ａと成分Ｂの複合比（Ｂ／Ａ）（重量比）を１／１とし
て表２に示した組み合わせ及び紡糸温度条件で溶融紡出
し，引取速度１０００ｍ／分で引取って，並列型複合フ
イラメント糸の未延伸糸条を得た。得られた未延伸糸条
を複数本集束しトウとして熱延伸をした。延伸に際して
は，２段熱ローラ延伸機を用い，延伸条件を延伸速度１
００ｍ／分，第１ローラ温度６０℃，第２ローラ温度９
０℃，第３ローラ温度２５℃とし，最大延伸倍率の８０
％の延伸倍率で延伸を行った。延伸に連続して，延伸ト
ウをスタツフアボツクスに供給して１４個／２５ｍｍの
捲縮を付与し仕上げ油剤を付与した後，温度７０℃で乾
燥し，繊維長５１ｍｍに切断し，単繊維繊度が２デニー
ルの並列型複合短繊維の原綿を得た。次いで，得られた
原綿に，温度１２０℃で１分間の熱処理を施した。な
お，表１において，イ〜ホ，ヨ及びタは通常の単一重合
体，ヘ〜オ及びカはランダム共重合体，ワはブロツク共
重合体である。複合短繊維を構成する重合体成分の組み
合わせ及び紡糸温度条件を表２に，得られた原綿の特性
と曵糸性，延伸性の結果を表３に，原綿及び熱処理を施
した綿の微細構造の測定結果を表４及び表５に示す。Examples 1 to 11 and Comparative Examples 1 to 9 Component A was a polypropylene copolymer having the Q value, melt flow rate value and melting point shown in Table 1 and having propylene and ethylene copolymerized at random. A polypropylene polymer having a Q value, a melt flow rate value and a melting point shown in Table 1, or a polypropylene copolymer obtained by random or block copolymerization of propylene and ethylene is used as a component B. After melting in a machine, a spinneret having a spinning hole diameter of 0.5 mm and a number of holes of 300 was used, and the discharge amount of each single hole was 0.5 g / min, that is, the composite ratio (B / A) of component A and component B (weight Ratio) to 1/1 and melt-spun under the combinations and spinning temperature conditions shown in Table 2 and withdrawn at a take-up speed of 1000 m / min to obtain an undrawn yarn of the parallel composite filament yarn. Obtained. A plurality of the obtained undrawn yarns were bundled and hot drawn as a tow. At the time of stretching, a two-stage hot roller stretching machine was used.
00m / min, first roller temperature 60 ° C, second roller temperature 9
0 ° C, third roller temperature 25 ° C, maximum draw ratio 80
The stretching was performed at a stretching ratio of%. Continuing with the drawing, the drawn tow is supplied to a staple box, a crimp of 14 pieces / 25 mm is applied, and a finishing oil is applied, dried at a temperature of 70 ° C., cut into a fiber length of 51 mm, and cut into a single fiber fineness. Obtained 2 denier parallel type composite short fiber raw cotton. Next, the obtained raw cotton was subjected to a heat treatment at a temperature of 120 ° C. for 1 minute. In Table 1, A to E, Y and T are ordinary homopolymers, H to O and F are random copolymers, and W is a block copolymer. Table 2 shows the combinations of the polymer components constituting the conjugate staple fiber and the spinning temperature conditions. Table 3 shows the characteristics of the obtained raw cotton and the results of spinning and drawing properties. Table 3 shows the fine structure of the raw cotton and the heat-treated cotton. Are shown in Tables 4 and 5.

【００３４】[0034]

【表１】 [Table 1]

【００３５】[0035]

【表２】 [Table 2]

【００３６】[0036]

【表３】 [Table 3]

【００３７】[0037]

【表４】 [Table 4]

【００３８】[0038]

【表５】 [Table 5]

【００３９】表２及び表３から明らかなように，本発明
の要件を満足する原綿は，温度１２０℃及び初荷重２ｍ
ｇ条件における乾熱収縮率が３５％以上で，かつ温度１
２０℃で熱処理後の捲縮数が６０個／２５ｍｍ以上であ
り，高収縮性と高捲縮性を有するものであった。また，
短繊維のメルトフローレート値が１５ｇ／１０分以上４
５ｇ／１０分以下であり，曵糸性と延伸性とも良好であ
った。比較例１では，重合体成分Ａと重合体成分Ｂの溶
融後のメルトフローレート値比（Ｂ／Ａ）が６／１を超
えているため溶融紡糸時の紡糸孔部におけるニーイング
が強く発生し，曵糸性が低下した。比較例２では，溶融
後のメルトフローレート値比が１／１未満であり曵糸性
は良好であるものの，乾熱収縮率が低下した。比較例３
では，エチレンのランダム共重合量が少なく，乾熱収縮
率が低下した。比較例４では，曵糸性が劣るブロツク共
重合体を重合体成分Ｂとして用いているため，重合体成
分Ａと複合しているにもかかわらず曵糸性が低下した。
比較例５では，短繊維のメルトフローレート値が４５ｇ
／１０分以上でありポリプロピレン系重合体の重合度が
低すぎて分解するため多量のガスが発生し，紡糸室の環
境が悪化した。比較例６及び７では，短繊維のメルトフ
ローレート値が１５ｇ／１０分未満であり，曵糸性と延
伸性が低下し，しかも紡糸温度を高く設定しなければな
らなかったためポリプロピレン系重合体が分解して多量
のガスが発生し，紡糸室の環境が悪化した。比較例８で
は，重合体成分ＢのＱ値が高く，溶融紡糸時の糸条冷却
が悪くなって曵糸性が低下した。比較例９では，重合体
成分ＢのＱ値が低く，延伸性が低下し，しかも得られた
短繊維は，温度１２０℃及び初荷重２ｍｇ条件における
乾熱収縮率と温度１２０℃で熱処理後の捲縮数がいずれ
も低いものであった。また，表５に示した繊維の微細構
造の測定結果から明らかなように，熱処理前の長周期が
大きい比較例２及び結晶体積が大きい比較例３では，乾
熱収縮率が低く，捲縮特性が十分発揮されなかった。As is clear from Tables 2 and 3, the raw cotton satisfying the requirements of the present invention was obtained at a temperature of 120 ° C. and an initial load of 2 m.
g under dry heat shrinkage of 35% or more
The number of crimps after heat treatment at 20 ° C. was 60 pieces / 25 mm or more, and had high shrinkage and high crimpability. Also,
Melt flow rate of short fiber is more than 15g / 10min4
It was 5 g / 10 minutes or less, and both the spinnability and the stretchability were good. In Comparative Example 1, since the melt flow rate value ratio (B / A) of the polymer component A and the polymer component B after melting was more than 6/1, the kneading at the spinning hole during the melt spinning occurred strongly. , The spinnability decreased. In Comparative Example 2, although the melt flow rate ratio after melting was less than 1/1 and the spinnability was good, the dry heat shrinkage ratio was low. Comparative Example 3
In, the amount of random copolymerization of ethylene was small, and the dry heat shrinkage decreased. In Comparative Example 4, since the block copolymer having poor spinnability was used as the polymer component B, the spinnability was reduced despite being composited with the polymer component A.
In Comparative Example 5, the melt flow rate of the short fiber was 45 g.
/ 10 minutes or more, the degree of polymerization of the polypropylene-based polymer was too low to decompose, so that a large amount of gas was generated, and the environment of the spinning chamber deteriorated. In Comparative Examples 6 and 7, the melt flow rate value of the short fiber was less than 15 g / 10 min, the spinnability and the stretchability were reduced, and the spinning temperature had to be set high. Decomposition generated a large amount of gas, and the environment of the spinning room deteriorated. In Comparative Example 8, the Q value of the polymer component B was high, the yarn cooling during melt spinning was poor, and the spinnability was low. In Comparative Example 9, the Q value of the polymer component B was low, the drawability was low, and the obtained short fibers had a dry heat shrinkage ratio at a temperature of 120 ° C and an initial load of 2 mg, and a heat-treated short fiber at a temperature of 120 ° C. The number of crimps was low. Further, as is clear from the measurement results of the microstructure of the fibers shown in Table 5, in Comparative Example 2 in which the long period before heat treatment was large and Comparative Example 3 in which the crystal volume was large, the dry heat shrinkage ratio was low and the crimp characteristics were low. Was not fully demonstrated.

【００４０】実施例１２〜１８及び比較例１０と１１ 表６に示した紡糸孔径の紡糸口金を用い，単孔吐出量を
表６に示したように設定した以外は，実施例３と同様に
して，並列型複合フイラメント糸を溶融紡出した。得ら
れた結果を表６に示す。Examples 12 to 18 and Comparative Examples 10 and 11 The same procedures as in Example 3 were carried out except that the spinneret having the spinning hole diameter shown in Table 6 was used and the single hole discharge amount was set as shown in Table 6. Then, the parallel composite filament yarn was melt spun. Table 6 shows the obtained results.

【００４１】[0041]

【表６】 [Table 6]

【００４２】表６から明らかなように，重合体成分Ａと
重合体成分Ｂの吐出線速度が２〜１０ｍ／分であると
き，良好な曵糸性と延伸性を得ることができた。As is clear from Table 6, when the discharge linear speed of the polymer component A and the polymer component B was 2 to 10 m / min, good spinnability and stretchability could be obtained.

【００４３】実施例１９〜２１及び比較例１２〜１４ 表７に示したように，前記実施例及び比較例で得られた
原綿をカーデイング機に供給して表７に示した目付けの
ウエブを作成し，９０メツシユのエンドレスの金網から
なり，かつ速度が２ｍ／分で移動するコンベア上に移
し，このウエブに第１回目の流体絡合処理を施した。第
１回目の流体絡合処理条件は，流体として水を採用し，
孔径が０．１ｍｍ，オリフイス間距離が１ｍｍのオリフ
イスを横１列に配設したオリフイスヘツドを使用し，オ
リフイス面とウエブ間の距離を５ｃｍ，オリフイスヘツ
ドの移動振幅を横方向に１ｍｍ，周期を１０往復／秒，
水噴流の水圧を２０ｋｇ／ｃｍ² とした。第１回目の流
体絡合処理に引き続き，ウエブに第２回目の流体絡合処
理を施した。第２回目の流体絡合処理条件は，流体とし
て水を採用し，孔径が０．１２５ｍｍ，オリフイス間距
離が１ｍｍのオリフイスを横２列に配設したオリフイス
ヘツドを使用し，オリフイス面とウエブ間の距離を５ｃ
ｍ，オリフイスヘツドの移動振幅を横方向に１ｍｍ，周
期を１０往復／秒，水噴流の水圧を７５ｋｇ／ｃｍ² と
した。なお，前記オリフイスヘツドにおいて，２列目の
オリフイスは，１列目の隣接する各オリフイス間の中点
から縦方向に延長した各線上に存在し，１列目と２列目
は幾何学的に平行に配設されている。前記第２回目の流
体絡合処理の後，第２回目の流体絡合処理と同一条件で
第３回目の流体絡合処理を施し，熱風循環式乾燥機を用
い温度１２０℃で１分間熱処理して不織布を製造した。
得られた不織布の性能を表７に，その微細構造の測定結
果を表８示す。Examples 19 to 21 and Comparative Examples 12 to 14 As shown in Table 7, the raw cottons obtained in the above Examples and Comparative Examples were supplied to a carding machine to produce webs having a basis weight shown in Table 7. Then, the web was transferred to a conveyor consisting of an endless wire mesh of 90 mesh and moving at a speed of 2 m / min, and the web was subjected to a first fluid entanglement treatment. The first fluid entanglement condition was to use water as the fluid,
An orifice head having a hole diameter of 0.1 mm and an orifice distance of 1 mm arranged in a row is used. The distance between the orifice surface and the web is 5 cm, the movement amplitude of the orifice head is 1 mm in the horizontal direction, and the cycle is 10 round trips / sec,
The water pressure of the water jet was 20 kg / cm ² . Subsequent to the first fluid entanglement process, the web was subjected to a second fluid entanglement process. The second fluid entanglement treatment was performed using water as the fluid, and using orifice heads having two rows of orifices with a hole diameter of 0.125 mm and a distance between orifices of 1 mm. Distance of 5c
m, the moving amplitude of the orifice head was 1 mm in the horizontal direction, the cycle was 10 reciprocations / second, and the water pressure of the water jet was 75 kg / cm ² . In the orifice head, the orifice in the second row exists on each line extending vertically from the midpoint between adjacent orifices in the first row, and the first and second rows are geometrically arranged. They are arranged in parallel. After the second fluid entanglement process, a third fluid entanglement process is performed under the same conditions as the second fluid entanglement process, and a heat treatment is performed for 1 minute at a temperature of 120 ° C. using a hot-air circulation dryer. To produce a non-woven fabric.
Table 7 shows the performance of the obtained nonwoven fabric, and Table 8 shows the measurement results of its microstructure.

【００４４】[0044]

【表７】 [Table 7]

【００４５】[0045]

【表８】 [Table 8]

【００４６】表７から明らかなように，本発明の方法で
得られた不織布は，見掛け密度が０．１０ｇ／ｃｍ³ 以
下で極めて嵩高性に優れ，しかも不織布の引張強力測定
における２０％及び５０％伸長時の伸長弾性率が縦横方
向共４０％以上であって，極めて形態安定性に優れたも
のであった。比較例１２〜１４では，いずれも５０％伸
長時の伸長弾性率が縦横方向共４０％未満であり，十分
な伸縮特性を有する不織布を得ることができなかった。
また，表８に示した不織布の微細構造の測定結果から明
らかなように，熱処理前の長周期が大きい比較例１３及
び結晶体積が大きい比較例１４では，伸縮特性が十分な
不織布を得ることができなかった。As is apparent from Table 7, the nonwoven fabric obtained by the method of the present invention has an apparent density of 0.10 g / cm ³ or less, is extremely excellent in bulkiness, and has a tensile strength of 20% and 50% in the measurement of tensile strength of the nonwoven fabric. The elongation modulus at% elongation was 40% or more in both the longitudinal and transverse directions, and the shape was extremely excellent in form stability. In Comparative Examples 12 to 14, the elongation modulus at 50% elongation was less than 40% in both the longitudinal and transverse directions, and a nonwoven fabric having sufficient elasticity could not be obtained.
In addition, as is apparent from the measurement results of the microstructure of the nonwoven fabric shown in Table 8, in Comparative Example 13 having a long long period before heat treatment and Comparative Example 14 having a large crystal volume, a nonwoven fabric having sufficient elasticity characteristics could be obtained. could not.

【００４７】実施例２２及び２３ 表１に示したポリプロピレン系共重合体チを成分Ａと
し，表１に示したポリプロピレン重合体ハ及びタを成分
Ｂとし，実施例１と同様にして，並列型複合フイラメン
ト糸の未延伸糸条を得た。得られた未延伸糸条を複数本
集束しトウとして熱延伸をした。延伸に際しては，２段
熱ローラ延伸機を用い，延伸条件を延伸速度１００ｍ／
分，第１ローラ温度５５℃，第２ローラ温度８５℃，第
３ローラ温度２５℃とし，最大延伸倍率の８０％の延伸
倍率で延伸を行った。延伸に連続して，延伸トウをギヤ
型リールにより引取り，仕上げ油剤を付与した後，温度
８０℃で乾燥し，繊維長５１ｍｍに切断し，単繊維繊度
が２デニールの並列型複合短繊維の原綿を得た。複合短
繊維を構成する重合体成分の組み合わせ及び紡糸温度条
件を表９に，得られた原綿の特性と曵糸性，延伸性の結
果を表１０に示す。Examples 22 and 23 In the same manner as in Example 1, the polypropylene copolymer (h) shown in Table 1 was used as the component A, and the polypropylene polymers (c) and (b) shown in Table 1 were used as the component B. An undrawn yarn of the composite filament yarn was obtained. A plurality of the obtained undrawn yarns were bundled and hot drawn as a tow. At the time of stretching, a two-stage hot roller stretching machine was used.
The first roller temperature was 55 ° C., the second roller temperature was 85 ° C., and the third roller temperature was 25 ° C., and the film was stretched at a stretch ratio of 80% of the maximum stretch ratio. Continuing with the drawing, the drawn tow is taken up by a gear-type reel, applied with a finishing oil, dried at a temperature of 80 ° C., cut into a fiber length of 51 mm, and cut into parallel type composite short fibers having a single fiber fineness of 2 denier. Raw cotton was obtained. Table 9 shows the combinations of the polymer components constituting the composite staple fiber and the spinning temperature conditions, and Table 10 shows the characteristics of the obtained raw cotton and the results of the spinnability and drawability.

【００４８】[0048]

【表９】 [Table 9]

【００４９】[0049]

【表１０】 [Table 10]

【００５０】表９及び表１０から明らかなように，本発
明の方法で得られた原綿は，温度１２０℃及び初荷重２
ｍｇ条件における乾熱収縮率が４１％，かつ温度１２０
℃で熱処理後の捲縮数が８３個／２５ｍｍであり，高収
縮性と高捲縮性を有するものであった。また，短繊維の
メルトフローレート値が２８ｇ／１０分であり，曵糸性
と延伸性とも良好であった。しかも，スタツフアボツク
スを用いなくても複合繊維に顕在捲縮を十分発現させる
ことができ，また，カード通過性も良好であった。な
お，実施例２３では，溶融紡糸後の重合体成分ＢのＱ値
が低く，延伸性がやや低下し，しかも得られた短繊維
は，温度１２０℃及び初荷重２ｍｇ条件における乾熱収
縮率と温度１２０℃で熱処理後の捲縮数がいずれもやや
低いものであった。As is clear from Tables 9 and 10, the raw cotton obtained by the method of the present invention has a temperature of 120 ° C. and an initial load of 2%.
The dry heat shrinkage rate under the mg condition is 41% and the temperature is 120.
The number of crimps after heat treatment at ℃ was 83 pieces / 25 mm, and it had high shrinkage and high crimpability. Further, the melt flow rate value of the short fibers was 28 g / 10 minutes, and both the spinnability and the stretchability were good. Moreover, the composite fiber was able to sufficiently express the apparent crimp without using the stuffing box, and the card passing property was also good. In Example 23, the Q value of the polymer component B after melt-spinning was low, the drawability was slightly lowered, and the obtained short fibers had a dry heat shrinkage ratio at a temperature of 120 ° C. and an initial load of 2 mg. The number of crimps after the heat treatment at a temperature of 120 ° C. was slightly lower.

【００５１】[0051]

【発明の効果】本発明の複合短繊維の製造方法は，前記
特定のポリプロピレン系共重合体を用いるものであり，
本発明によれば，高収縮性，高捲縮性，かつ高強度を有
する複合短繊維を得ることができる。また，本発明の不
織布の製造方法は，前記複合短繊維を用いるものであ
り，本発明によれば，伸縮性，嵩高性，柔軟性に優れ，
特に医療衛生材用素材として好適に使用することができ
る不織布を得ることができる。According to the method for producing a conjugate short fiber of the present invention, the specific polypropylene-based copolymer is used.
According to the present invention, a conjugate short fiber having high shrinkage, high crimpability, and high strength can be obtained. In addition, the method for producing a nonwoven fabric of the present invention uses the conjugate short fiber. According to the present invention, the stretchability, bulkiness, and flexibility are excellent.
In particular, a nonwoven fabric that can be suitably used as a material for medical hygiene materials can be obtained.

───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.⁶ 識別記号 ＦＩ // Ｄ０１Ｇ 1/00 Ｄ０１Ｇ 1/00 Ａ (58)調査した分野(Int.Cl.⁶，ＤＢ名) D04H 1/00 - 18/00 D01F 6/00 - 6/46 D01F 8/06──────────────────────────────────────────────────の Continuation of the front page (51) Int.Cl. ⁶ identification symbol FI // D01G 1/00 D01G 1/00 A (58) Investigated field (Int.Cl. ⁶ , DB name) D04H 1/00- 18/00 D01F 6/00-6/46 D01F 8/06

Claims (6)

(57)【特許請求の範囲】(57) [Claims] 【請求項１】 ９２重量％以上９７重量％以下のプロピ
レンと３重量％以上８重量％以下のエチレンがランダム
共重合されたポリプロピレン系共重合体成分Ａと，９７
重量％以上１００重量％以下のプロピレンと０重量％以
上３重量％以下のエチレンが共重合されたポリプロピレ
ン系共重合体成分Ｂとを複合成分とし，複合短繊維とし
たときのメルトフローレート値が１５ｇ／１０分以上４
５ｇ／１０分以下となるようにし，重合体成分Ａと重合
体成分Ｂの溶融後のメルトフローレート値比（Ｂ／Ａ）
を１／１〜６／１とし，かつ重合体成分Ａと重合体成分
Ｂの吐出線速度を２〜１０ｍ／分として溶融複合紡糸
し，得られた未延伸複合繊維を５０℃以上かつ繊維相互
が融着しない温度で熱延伸し，次いで得られた延伸複合
繊維に捲縮付与処理を施し，仕上げ油剤を付与した後乾
燥し，所定長さに切断して短繊維とすることを特徴とす
るポリプロピレン系短繊維の製造方法。1. A polypropylene-based copolymer component A obtained by random copolymerization of 92% by weight or more and 97% by weight or less of propylene and 3% by weight or more and 8% by weight or less of ethylene.
The melt flow rate of a composite staple fiber is defined as a composite component composed of propylene of at least 100% by weight and propylene of 0 to 3% by weight and a polypropylene copolymer component B having ethylene of at least 3% by weight. 15g / 10min or more 4
The melt flow rate value ratio (B / A) of the polymer component A and the polymer component B after melting so as to be 5 g / 10 minutes or less.
Is set to 1/1 to 6/1, and the discharge linear speed of the polymer component A and the polymer component B is set to 2 to 10 m / min. Hot drawn at a temperature that does not cause fusing, then applying crimping treatment to the obtained drawn conjugate fiber, applying a finishing oil agent, drying, and cutting into a predetermined length to obtain short fibers. A method for producing short polypropylene fibers. 【請求項２】 ９２重量％以上９７重量％以下のプロピ
レンと３重量％以上８重量％以下のエチレンがランダム
共重合され，かつＱ値（重量平均分子量／数平均分子
量）が８以下のポリプロピレン系共重合体成分Ａと，９
７重量％以上１００重量％以下のプロピレンと０重量％
以上３重量％以下のエチレンが共重合され，かつＱ値
（重量平均分子量／数平均分子量）が５以上８以下のポ
リプロピレン系共重合体成分Ｂとを複合成分とし，複合
短繊維としたときのメルトフローレート値が１５ｇ／１
０分以上４５ｇ／１０分以下となるようにし，重合体成
分Ａと重合体成分Ｂの溶融後のメルトフローレート値比
（Ｂ／Ａ）を１／１〜６／１とし，かつ重合体成分Ａと
重合体成分Ｂの吐出線速度を２〜１０ｍ／分として溶融
複合紡糸し，得られた未延伸複合繊維を５０℃以上かつ
繊維相互が融着しない温度で熱延伸し，次いで得られた
延伸複合繊維に捲縮付与処理を施し，仕上げ油剤を付与
した後乾燥し，所定長さに切断して短繊維とすることを
特徴とするポリプロピレン系短繊維の製造方法。2. A polypropylene system in which 92% by weight to 97% by weight of propylene and 3% by weight to 8% by weight of ethylene are randomly copolymerized and the Q value (weight average molecular weight / number average molecular weight) is 8 or less. Copolymer component A, 9
7% to 100% by weight of propylene and 0% by weight
When 3% by weight or less of ethylene is copolymerized and a polypropylene-based copolymer component B having a Q value (weight average molecular weight / number average molecular weight) of 5 or more and 8 or less is used as a composite component, a composite staple fiber is obtained. Melt flow rate value is 15g / 1
The melt flow rate value ratio (B / A) after melting of the polymer component A and the polymer component B is set to 1/1 to 6/1, and the polymer component A and the polymer component B are set to 1/1 to 6/1. A and the polymer component B were melt-spun at a discharge linear velocity of 2 to 10 m / min, and the obtained undrawn composite fiber was hot-drawn at a temperature of 50 ° C. or higher and at a temperature at which the fibers did not fuse with each other. A method for producing a polypropylene-based short fiber, comprising applying a crimping treatment to a drawn conjugate fiber, applying a finishing oil agent, drying, and cutting into a predetermined length to obtain a short fiber. 【請求項３】 ９２重量％以上９７重量％以下のプロピ
レンと３重量％以上８重量％以下のエチレンがランダム
共重合され，かつＱ値（重量平均分子量／数平均分子
量）が８以下のポリプロピレン系共重合体成分Ａと，９
７重量％以上１００重量％以下のプロピレンと０重量％
以上３重量％以下のエチレンが共重合され，かつＱ値
（重量平均分子量／数平均分子量）が５以上８以下のポ
リプロピレン系共重合体成分Ｂとを複合成分とし，複合
短繊維としたときのメルトフローレート値が１５ｇ／１
０分以上４５ｇ／１０分以下となるようにし，重合体成
分Ａと重合体成分Ｂの溶融後のメルトフローレート値比
（Ｂ／Ａ）を１／１〜６／１とし，かつ重合体成分Ａと
重合体成分Ｂの吐出線速度を２〜１０ｍ／分として溶融
複合紡糸し，得られた未延伸複合繊維を５０℃以上かつ
繊維相互が融着しない温度で熱延伸して下記条件（１）
〜（３）を満足する複合繊維とし，次いで得られた延伸
複合繊維に捲縮付与処理を施し，仕上げ油剤を付与した
後乾燥し，所定長さに切断して短繊維とすることを特徴
とするポリプロピレン系短繊維の製造方法。 （１）熱処理前の複合短繊維の共重合体成分Ａ部分の複
屈折と共重合体成分Ｂ部分の複屈折が共に０．０２以上
であること， （２）広角Ｘ線回折法により測定される熱処理前の複合
短繊維の結晶体積が１０００００ų 以下であること， （３）小角Ｘ線散乱法により測定される熱処理前の複合
短繊維の長周期が１３０Å未満であること。3. A polypropylene system in which 92% by weight to 97% by weight of propylene and 3% by weight to 8% by weight of ethylene are randomly copolymerized and the Q value (weight average molecular weight / number average molecular weight) is 8 or less. Copolymer component A, 9
7% to 100% by weight of propylene and 0% by weight
When 3% by weight or less of ethylene is copolymerized and a polypropylene-based copolymer component B having a Q value (weight average molecular weight / number average molecular weight) of 5 or more and 8 or less is used as a composite component, a composite staple fiber is obtained. Melt flow rate value is 15g / 1
The melt flow rate value ratio (B / A) after melting of the polymer component A and the polymer component B is set to 1/1 to 6/1, and the polymer component A and the polymer component B are set to 1/1 to 6/1. A and the polymer component B are melt-spun at a discharge linear velocity of 2 to 10 m / min, and the obtained undrawn conjugate fiber is hot-drawn at a temperature of 50 ° C. or more and at a temperature at which the fibers are not fused to each other. )
(3), then subjecting the obtained stretched conjugate fiber to crimping treatment, applying a finishing oil agent, drying, and cutting into a predetermined length to obtain short fibers. For producing polypropylene short fibers. (1) The birefringence of the copolymer component A portion and the birefringence of the copolymer component B portion of the conjugate short fiber before heat treatment are both 0.02 or more. (2) Measured by wide-angle X-ray diffraction. that the crystal volume of the composite short fibers before the heat treatment is 100000 ³ or less, (3) long period of composite short fibers before the heat treatment as measured by small-angle X-ray scattering method is less than 130 Å. 【請求項４】 ９２重量％以上９７重量％以下のプロピ
レンと３重量％以上８重量％以下のエチレンがランダム
共重合されたポリプロピレン系共重合体成分Ａと，９７
重量％以上１００重量％以下のプロピレンと０重量％以
上３重量％以下のエチレンが共重合されたポリプロピレ
ン系共重合体成分Ｂとを複合成分とし，複合短繊維とし
たときのメルトフローレート値が１５ｇ／１０分以上４
５ｇ／１０分以下となるようにし，重合体成分Ａと重合
体成分Ｂの溶融後のメルトフローレート値比（Ｂ／Ａ）
を１／１〜６／１とし，かつ重合体成分Ａと重合体成分
Ｂの吐出線速度を２〜１０ｍ／分として溶融複合紡糸
し，得られた未延伸複合繊維を５０℃以上かつ繊維相互
が融着しない温度で熱延伸し，次いで得られた延伸複合
繊維に捲縮付与処理を施し，仕上げ油剤を付与した後乾
燥し，所定長さに切断して短繊維とし，次いで得られた
複合短繊維５０重量％以上を用いてカードウエブを作成
し，このカードウエブを多孔性支持部材上に載置し，圧
力が３０ｋｇ／ｃｍ² 未満の流体噴流により前記ウエブ
に流体絡合処理を施した後，圧力が５０ｋｇ／ｃｍ² 以
上の流体噴流により前記ウエブに流体絡合処理を施して
ウエブを構成する前記複合短繊維相互を三次元的に絡合
させ，引き続きウエブに乾熱処理を施して水分を除去す
るとともに複合短繊維に捲縮を発現させることを特徴と
する不織布の製造方法。4. A polypropylene-based copolymer component A obtained by random copolymerization of 92% by weight or more and 97% by weight or less of propylene and 3% by weight or more and 8% by weight or less of ethylene.
The melt flow rate of a composite staple fiber is defined as a composite component composed of propylene of at least 100% by weight and propylene of 0 to 3% by weight and a polypropylene copolymer component B having ethylene of at least 3% by weight. 15g / 10min or more 4
The melt flow rate value ratio (B / A) of the polymer component A and the polymer component B after melting so as to be 5 g / 10 minutes or less.
Is set to 1/1 to 6/1, and the discharge linear speed of the polymer component A and the polymer component B is set to 2 to 10 m / min. Is drawn at a temperature that does not cause fusing, then the obtained drawn conjugate fiber is subjected to a crimping treatment, applied with a finishing oil, dried, cut into a predetermined length to obtain short fibers, and then the obtained conjugate A card web was prepared using 50% by weight or more of short fibers, the card web was placed on a porous support member, and the web was subjected to a fluid entanglement treatment by a fluid jet having a pressure of less than 30 kg / cm ² . Thereafter, the web is subjected to a fluid entanglement treatment by a fluid jet having a pressure of 50 kg / cm ² or more to three-dimensionally entangle the composite short fibers constituting the web. Removes and composite staple fiber A method for producing a nonwoven fabric, characterized in that a crimp is developed on the nonwoven fabric. 【請求項５】 ９２重量％以上９７重量％以下のプロピ
レンと３重量％以上８重量％以下のエチレンがランダム
共重合され，かつＱ値（重量平均分子量／数平均分子
量）が８以下のポリプロピレン系共重合体成分Ａと，９
７重量％以上１００重量％以下のプロピレンと０重量％
以上３重量％以下のエチレンが共重合され，かつＱ値
（重量平均分子量／数平均分子量）が５以上８以下のポ
リプロピレン系共重合体成分Ｂとを複合成分とし，複合
短繊維としたときのメルトフローレート値が１５ｇ／１
０分以上４５ｇ／１０分以下となるようにし，重合体成
分Ａと重合体成分Ｂの溶融後のメルトフローレート値比
（Ｂ／Ａ）を１／１〜６／１とし，かつ重合体成分Ａと
重合体成分Ｂの吐出線速度を２〜１０ｍ／分として溶融
複合紡糸し，得られた未延伸複合繊維を５０℃以上かつ
繊維相互が融着しない温度で熱延伸し，次いで得られた
延伸複合繊維に捲縮付与処理を施し，仕上げ油剤を付与
した後乾燥し，所定長さに切断して短繊維とし，次いで
得られた複合短繊維５０重量％以上を用いてカードウエ
ブを作成し，このカードウエブを多孔性支持部材上に載
置し，圧力が３０ｋｇ／ｃｍ² 未満の流体噴流により前
記ウエブに流体絡合処理を施した後，圧力が５０ｋｇ／
ｃｍ² 以上の流体噴流により前記ウエブに流体絡合処理
を施してウエブを構成する前記複合短繊維相互を三次元
的に絡合させ，引き続きウエブに乾熱処理を施して水分
を除去するとともに複合短繊維に捲縮を発現させること
を特徴とする不織布の製造方法。5. A polypropylene system in which 92% by weight to 97% by weight of propylene and 3% by weight to 8% by weight of ethylene are randomly copolymerized and the Q value (weight average molecular weight / number average molecular weight) is 8 or less. Copolymer component A, 9
7% to 100% by weight of propylene and 0% by weight
When 3% by weight or less of ethylene is copolymerized and a polypropylene-based copolymer component B having a Q value (weight average molecular weight / number average molecular weight) of 5 or more and 8 or less is used as a composite component, a composite staple fiber is obtained. Melt flow rate value is 15g / 1
The melt flow rate value ratio (B / A) after melting of the polymer component A and the polymer component B is set to 1/1 to 6/1, and the polymer component A and the polymer component B are set to 1/1 to 6/1. A and the polymer component B were melt-spun at a discharge linear velocity of 2 to 10 m / min, and the obtained undrawn composite fiber was hot-drawn at a temperature of 50 ° C. or higher and at a temperature at which the fibers did not fuse with each other. The drawn conjugate fiber is subjected to crimping treatment, applied with a finishing oil agent, dried, cut into a predetermined length to obtain short fibers, and then a card web is prepared using 50% by weight or more of the obtained conjugate short fibers. After placing the card web on a porous support member and subjecting the web to a fluid entanglement treatment by a fluid jet having a pressure of less than 30 kg / cm ² , the pressure is reduced to 50 kg / cm ^2.
The web is subjected to a fluid entanglement treatment by a fluid jet of at least ² cm so that the composite short fibers constituting the web are three-dimensionally entangled with each other. A method for producing a nonwoven fabric, wherein a crimp is developed in a fiber. 【請求項６】 ９２重量％以上９７重量％以下のプロピ
レンと３重量％以上８重量％以下のエチレンがランダム
共重合され，かつＱ値（重量平均分子量／数平均分子
量）が８以下のポリプロピレン系共重合体成分Ａと，９
７重量％以上１００重量％以下のプロピレンと０重量％
以上３重量％以下のエチレンが共重合され，かつＱ値
（重量平均分子量／数平均分子量）が５以上８以下のポ
リプロピレン系共重合体成分Ｂとを複合成分とし，複合
短繊維としたときのメルトフローレート値が１５ｇ／１
０分以上４５ｇ／１０分以下となるようにし，重合体成
分Ａと重合体成分Ｂの溶融後のメルトフローレート値比
（Ｂ／Ａ）を１／１〜６／１とし，かつ重合体成分Ａと
重合体成分Ｂの吐出線速度を２〜１０ｍ／分として溶融
複合紡糸し，得られた未延伸複合繊維を５０℃以上かつ
繊維相互が融着しない温度で熱延伸して下記条件（１）
〜（３）を満足する複合繊維とし，次いで得られた延伸
複合繊維に捲縮付与処理を施し，仕上げ油剤を付与した
後乾燥し，所定長さに切断して短繊維とし，次いで得ら
れた複合短繊維５０重量％以上を用いてカードウエブを
作成し，このカードウエブを多孔性支持部材上に載置
し，圧力が３０ｋｇ／ｃｍ² 未満の流体噴流により前記
ウエブに流体絡合処理を施した後，圧力が５０ｋｇ／ｃ
ｍ² 以上の流体噴流により前記ウエブに流体絡合処理を
施してウエブを構成する前記複合短繊維相互を三次元的
に絡合させ，引き続きウエブに乾熱処理を施して水分を
除去するとともに複合短繊維に下記条件（４）〜（６）
を満足させ，かつ捲縮を発現させることを特徴とする不
織布の製造方法。 （１）熱処理前の複合短繊維の共重合体成分Ａ部分の複
屈折と共重合体成分Ｂ部分の複屈折が共に０．０２以上
であること， （２）広角Ｘ線回折法により測定される熱処理前の複合
短繊維の結晶体積が１０００００ų 以下であること， （３）小角Ｘ線散乱法により測定される熱処理前の複合
短繊維の長周期が１３０Å未満であること， （４）熱処理後の複合短繊維の共重合体成分Ａ部分の複
屈折と共重合体成分Ｂ部分の複屈折が共に上記熱処理前
の複合短繊維の共重合体成分Ａ部分の複屈折と共重合体
成分Ｂ部分の複屈折よりそれぞれ低いこと， （５）広角Ｘ線回折法により測定される熱処理後の複合
短繊維の結晶体積が２０００００ų 以上であること， （６）小角Ｘ線散乱法により測定される熱処理後の複合
短繊維の長周期が１３０Å以上であること。6. A polypropylene system in which 92% by weight to 97% by weight of propylene and 3% by weight to 8% by weight of ethylene are randomly copolymerized and the Q value (weight average molecular weight / number average molecular weight) is 8 or less. Copolymer component A, 9
7% to 100% by weight of propylene and 0% by weight
When 3% by weight or less of ethylene is copolymerized and a polypropylene-based copolymer component B having a Q value (weight average molecular weight / number average molecular weight) of 5 or more and 8 or less is used as a composite component, a composite staple fiber is obtained. Melt flow rate value is 15g / 1
The melt flow rate value ratio (B / A) after melting of the polymer component A and the polymer component B is set to 1/1 to 6/1, and the polymer component A and the polymer component B are set to 1/1 to 6/1. A and the polymer component B are melt-spun at a discharge linear velocity of 2 to 10 m / min, and the obtained undrawn conjugate fiber is hot-drawn at a temperature of 50 ° C. or more and at a temperature at which the fibers are not fused to each other. )
To (3), and then subjected to a crimping treatment on the obtained drawn composite fiber, applied with a finishing oil agent, dried, cut into a predetermined length to obtain short fibers, and then obtained. A card web is prepared by using 50% by weight or more of the composite staple fiber, and the card web is placed on a porous support member, and the web is subjected to a fluid entanglement treatment by a fluid jet having a pressure of less than 30 kg / cm ^2. After that, the pressure is 50kg / c
subjected to fluid entangling treatment to said web by m ² or more fluid jets to the composite short fibers each other three-dimensionally entangled constituting the web, subsequently the composite short to remove the water is subjected to dry heat treatment the web The following conditions (4) to (6) for the fiber
A method for producing a non-woven fabric, characterized by satisfying the above-mentioned conditions and exhibiting crimp. (1) The birefringence of the copolymer component A portion and the birefringence of the copolymer component B portion of the conjugate short fiber before heat treatment are both 0.02 or more. (2) Measured by wide-angle X-ray diffraction. that the crystal volume of the composite short fibers before the heat treatment is 100000 ³ or less, (3) long period of composite short fibers before the heat treatment as measured by small-angle X-ray scattering method is less than 130 Å, (4) thermal treatment Both the birefringence of the copolymer component A portion of the composite staple fiber and the birefringence of the copolymer component B portion of the composite staple fiber after the birefringence of the copolymer component A portion of the composite staple fiber before the heat treatment and the copolymer component B respectively than the birefringence part lower, as measured by (5) the crystal volume of the composite staple fibers after the heat treatment as measured by wide angle X-ray diffraction method is 200000A ³ or more, (6) small-angle X-ray scattering method Long cycle of composite short fiber after heat treatment is 130 That is greater than or equal to.