JP2009114619A - Polylactic acid conjugated staple fiber and method for production thereof - Google Patents
Polylactic acid conjugated staple fiber and method for production thereof Download PDFInfo
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本発明は、生分解性を有し、耐久性のある熱バインダー特性に優れたポリ乳酸系複合短繊維及びその製造方法に関するものである。 The present invention relates to a polylactic acid-based composite short fiber that is biodegradable and has excellent durable thermal binder properties and a method for producing the same.
一般に、機能の一つである接着性を有する合成繊維として、所謂熱バインダー繊維がある。この熱バインダー繊維とは、加熱によって接着する自己接着性を持つものであり、このような繊維を用いて、糸、編み物、織物、不織布、その他の繊維構造物を製造する過程で、または製造した後加熱することで繊維が互いに接着し、強固な製品が得られるため、近年、その需要量が多くなっている。合成重合体からなる従来の繊維は、自然環境下での分解速度が遅く、また焼却する場合にはその時の発熱量が多いため、自然環境保護の見地からの改善が必要である。最近、脂肪族ポリエステルからなる生分解性繊維が開発されつつあり、環境保護への貢献が期待されている。しかも、脂肪族ポリエステルからなる繊維は、優れた繊維性能を持ち、新規な繊維素材として期待されている。しかしながら、この重合体は融点が低いため、また耐久性のあるバインダー特性に乏しく、用途が限定されていた。そこで、かかる問題を解決すべく、特開平６−２０７３２０号公報や特開平６−２０７３２４号公報において芯成分が高融点重合体、鞘成分が低融点重合体の生分解性自己接着性短繊維あるいは長繊維が、また特開平６−２１２５４８号公報において高融点重合体と低融点重合体とからなり潜在捲縮能を有する生分解性自己接着性短繊維とその繊維からなる不織布が提案されている。また、特開平９−１５７９５２号公報や特開平９−２０９２１６号公報にも、同主旨の複合繊維が提案されている。しかしながら、これら公開特許公報に記載の複合繊維は、いずれも、融点が異なる異種の２重合体成分や、主体重合体とその共重合体との組み合わせでなどで構成されるため、前者においては、熱接着後に重合体成分間に剥離が生じ、一見強固に観えた接着性が繰り返し使用時には低下し、強力低下や毛羽立ち等の問題が生じる。後者においては、異成分との共重合体を構成成分とするため、繊維の長さ方向で２成分間の接着強力が異なり、繰り返し使用時には、強力低下や毛羽立ちが生じる。したがって、これら公開特許公報に記載の複合繊維やその不織布は、用途が限定されるという問題がある。
本発明は、生分解性を有し、熱バインダー特性に優れ、繰り返し使用した時にも熱バインダー特性が低下せず耐久性があるポリ乳酸系複合短繊維及びその製造方法を提供する。 The present invention provides a polylactic acid-based composite short fiber that is biodegradable, has excellent thermal binder properties, and does not deteriorate the thermal binder properties even when used repeatedly, and a method for producing the same .
本発明者らは、前記問題点を解決すべく鋭意検討した結果、本発明に到達したもので、すなわち、本発明は、以下をその要旨とするものである。
１）相互に光学純度が５〜２０％異なる２種のポリ乳酸系重合体Ａ及びＢからなり、該重合体Ａのメルトフローレート値ＭＦＲ（Ａ）と該重合体Ｂのメルトフローレート値ＭＦＲ（Ｂ）とが下記式（１）〜（３）を満足し、かつ低光学純度の該重合体Ｂが繊維表面の一部に露出する如く複合されていることを特徴とするポリ乳酸系複合短繊維。
５≦ＭＦＲ（Ａ）≦１００ ・・・・・（１）
５≦ＭＦＲ（Ｂ）≦８０ ・・・・・（２）
ＭＦＲ（Ａ）≧ＭＦＲ（Ｂ）・・・・・（３）
ＭＦＲ（Ａ）：光学純度が高い重合体Ａのメルトフローレート（ｇ／１０分）
ＭＦＲ（Ｂ）：重合体Ａよりも光学純度が低い重合体Ｂのメルトフローレート（ｇ／１０分）
２）重合体Ｂ中には、少なくとも結晶核剤が添加されていることを特徴とする１）に記載のポリ乳酸系複合短繊維。
３）相互に光学純度を５〜２０％異にする２種のポリ乳酸系重合体Ａ及びＢであって、重合体Ａのメルトフローレート値ＭＦＲ（Ａ）と重合体Ｂのメルトフローレート値ＭＦＲ（Ｂ）とが下記式（１）〜（３）を満足する重合体を、低光学純度の該重合体Ｂが繊維表面の一部に露出する如く溶融複合紡糸した後、熱延伸することを特徴とするポリ乳酸系複合短繊維の製造方法。
５≦ＭＦＲ（Ａ）≦１００ ・・・・・（１）
５≦ＭＦＲ（Ｂ）≦８０ ・・・・・（２）
ＭＦＲ（Ａ）≧ＭＦＲ（Ｂ）・・・・・（３）
ＭＦＲ（Ａ）：光学純度が高い重合体Ａのメルトフローレート（ｇ／１０分）
ＭＦＲ（Ｂ）：重合体Ａよりも光学純度が低い重合体Ｂのメルトフローレート（ｇ／１０分）
４）重合体Ｂ中には、少なくとも結晶核剤が添加されていることを特徴とする３）に記載のポリ乳酸系複合短繊維の製造方法。
The inventors of the present invention have arrived at the present invention as a result of intensive studies to solve the above problems, that is, the present invention has the following gist.
1) It consists of two kinds of polylactic acid polymers A and B having optical purity of 5 to 20% different from each other. The melt flow rate value MFR (A) of the polymer A and the melt flow rate value MFR of the polymer B A polylactic acid-based composite characterized in that (B) satisfies the following formulas (1) to (3) and is composited so that the polymer B having a low optical purity is exposed on a part of the fiber surface Short fiber.
5 ≦ MFR (A) ≦ 100 (1)
5 ≦ MFR (B) ≦ 80 (2)
MFR (A) ≧ MFR (B) (3)
MFR (A): Melt flow rate of polymer A having high optical purity (g / 10 min)
MFR (B): Melt flow rate of polymer B having a lower optical purity than polymer A (g / 10 min)
2) The polylactic acid based composite short fiber according to 1), wherein at least a crystal nucleating agent is added to the polymer B.
3) Two types of polylactic acid polymers A and B having optical purity different from each other by 5 to 20%, the melt flow rate value MFR (A) of the polymer A and the melt flow rate value of the polymer B A polymer in which MFR (B) satisfies the following formulas (1) to (3) is melt-combined and spun so that the polymer B of low optical purity is exposed on a part of the fiber surface, and then hot-drawn. A process for producing a polylactic acid-based composite short fiber characterized by the above.
5 ≦ MFR (A) ≦ 100 (1)
5 ≦ MFR (B) ≦ 80 (2)
MFR (A) ≧ MFR (B) (3)
MFR (A): Melt flow rate of polymer A having high optical purity (g / 10 min)
MFR (B): Melt flow rate of polymer B having a lower optical purity than polymer A (g / 10 min)
4) The method for producing a polylactic acid-based composite short fiber according to 3), wherein at least a crystal nucleating agent is added to the polymer B.
本発明のポリ乳酸系複合短繊維は、実用的な繊維強度を有し、生分解性を有することから自然環境を汚染することがなく、しかも耐久性のある熱バインダー特性に優れたものである。この短繊維は、異素材との熱接着性も良好で、しかも熱接着後の寸法安定性にも優れるため、織物、編物、不織布、その他の繊維構造物、複合構造物などに適用出来るところから、衣料、産業資材、家庭用品、土木資材、農業資材、林業資材などの用途に好適である。特に、この短繊維からなる不織布は、実用的な強力を有し、耐久性のある熱バインダー特性に優れることから、例えばクツシヨン材、フイルター、植生シート、法面緑化シート、土砂流失防止シート、台所用水切り袋、ごみ袋、ワイパ−、ナプキン、おしぼり、食品包装材、煮出し用パツク、木質ボード、自動車用内装材などの用途に好適である。 The polylactic acid-based composite short fiber of the present invention has practical fiber strength and biodegradability, so it does not pollute the natural environment and has excellent durable thermal binder properties. . This short fiber has good thermal adhesiveness with different materials and also has excellent dimensional stability after thermal bonding, so it can be applied to woven fabrics, knitted fabrics, nonwoven fabrics, other fiber structures, composite structures, etc. Suitable for applications such as clothing, industrial materials, household goods, civil engineering materials, agricultural materials, forestry materials. In particular, this non-woven fabric made of short fibers has practical strength and is excellent in durable thermal binder properties. For example, bushy materials, filters, vegetation sheets, slope greening sheets, sediment loss prevention sheets, kitchens, etc. It is suitable for applications such as water draining bags, garbage bags, wipers, napkins, towels, food packaging materials, boiled packs, wooden boards, and automobile interior materials.
次に、本発明を詳細に説明する。先ず、本発明のポリ乳酸系複合短繊維について説明する。本発明のポリ乳酸系繊維におけるポリ乳酸系重合体は、Ｌ−乳酸またはＤ−乳酸またはそれらのブレンドによる光学異性体の重合体を主成分とするもので、したがって異成分同士の共重合ではなく同一の素材であるため、繊維を製造するに際して極めて製糸特性が優れる。Ｌ−乳酸の光学純度が０〜１００％存在する中で、このＬ体に対するＤ体の比率は、耐熱性や生分解性に影響する要因であり、Ｄ体によってＬ体の純度が低くなると、それに伴って結晶性が低下し、また融点降下が大きくなり、熱接着性が向上する方向にある。また、柔軟性や弾性回復性が改良され、熱収縮性が増大し、分解性やガラス転移温度の制御、他成分との接着性の改良などができる。一方、Ｄ−乳酸の光学純度が０〜１００％存在する中で、このＤ体に対するＬ体の比率は、同様に耐熱性や生分解性に影響する要因であり、Ｌ体によってＤ体の純度が低くなると、それに伴って結晶性が低下し、また融点降下が大きくなり、熱接着性が向上する方向にある。また、柔軟性や弾性回復性が改良され、熱収縮性が増大し、分解性やガラス転移温度の制御、他成分との接着性の改良などができる。このようなところから、Ｌ体とＤ体とのブレンド比（重量比）が１：１であると、最も結晶性が低下し、かつ熱接着性が向上する。また同時に、生分解速度も最も高くなる。本発明が採用するポリ乳酸系重合体は、純粋なポリ乳酸であり、Ｌ体またはＤ体を主体成分とするものである。その中で、光学純度に差がある２種のポリ乳酸系重合体を選定して採用し、その光学純度が５〜２０％異なる必要性は、ポリ乳酸の純度がこの範囲より小さいと、得られた繊維において熱バインダー特性が低下し、加熱時の熱処理範囲の低下や用途範囲が極めて狭くなるという問題が生じるからである。しかも、結晶化が高くなり過ぎて分解速度が低くなり、生分解性に劣った繊維となる。一方、ポリ乳酸の純度がこの範囲よりも大きくなると、繊維を熱延伸するに際して糸条間に密着が生じたり、熱収縮が極めて高くなり、問題となる。また、乾燥工程などの低温処理下においても糸条間に密着や融着が生じて、実用に絶えなくなる。したがって、本発明においては、２種のポリ乳酸系重合体の組み合わせを光学純度が５〜２０％異なる範囲のもの同士とするが、好ましくは光学純度が６〜１８％異なるもの同士、より好ましくは光学純度が８〜１６％異なるもの同士、最も好ましくは光学純度が１０〜１４％異なるもの同士とするのがよい。 Next, the present invention will be described in detail. First, the polylactic acid composite short fiber of the present invention will be described. The polylactic acid polymer in the polylactic acid fiber of the present invention is mainly composed of an optical isomer polymer of L-lactic acid, D-lactic acid or a blend thereof, and is not a copolymer of different components. Since they are the same material, they are extremely excellent in spinning characteristics when producing fibers. While the optical purity of L-lactic acid is 0 to 100%, the ratio of the D form to the L form is a factor affecting the heat resistance and biodegradability. When the purity of the L form is lowered by the D form, As a result, the crystallinity is lowered, the melting point drop is increased, and the thermal adhesiveness is improved. In addition, flexibility and elastic recovery are improved, heat shrinkability is increased, decomposability and glass transition temperature can be controlled, and adhesion with other components can be improved. On the other hand, while the optical purity of D-lactic acid is 0 to 100%, the ratio of L-form to D-form is a factor that similarly affects heat resistance and biodegradability. When it becomes low, crystallinity falls in connection with it, and melting | fusing point fall becomes large, and it exists in the direction which improves thermal adhesiveness. In addition, flexibility and elastic recovery are improved, heat shrinkability is increased, decomposability and glass transition temperature can be controlled, and adhesion with other components can be improved. From this point, when the blend ratio (weight ratio) of the L-form and the D-form is 1: 1, the crystallinity is most lowered and the thermal adhesiveness is improved. At the same time, the biodegradation rate is the highest. The polylactic acid-based polymer employed in the present invention is pure polylactic acid and contains L-form or D-form as a main component. Among them, two types of polylactic acid polymers having a difference in optical purity are selected and adopted, and the necessity of different optical purity by 5 to 20% is obtained when the purity of polylactic acid is smaller than this range. This is because the thermal binder characteristics of the obtained fibers are deteriorated, resulting in a problem that the heat treatment range during heating and the application range are extremely narrow. In addition, the crystallization becomes too high, the degradation rate is lowered, and the fiber is inferior in biodegradability. On the other hand, when the purity of the polylactic acid is larger than this range, there is a problem that when the fiber is hot-drawn, adhesion between the yarns occurs or the heat shrinkage becomes extremely high. Further, even under low-temperature treatment such as a drying process, adhesion and fusion occur between the yarns, and it is not practically used. Therefore, in the present invention, the combination of two types of polylactic acid polymers is different in the optical purity range of 5 to 20%, but preferably in the optical purity difference of 6 to 18%, more preferably The optical purity is 8 to 16% different, most preferably the optical purity is 10 to 14% different.
また、本発明のポリ乳酸系繊維では、前記２種のポリ乳酸系重合体Ａ及びＢの溶融粘度すなわち本発明の繊維を構成する重合体Ａのメルトフローレート値ＭＦＲ（Ａ）と重合体Ｂのメルトフローレート値ＭＦＲ（Ｂ）とが上記式（１）〜（３）を満足することが必要である。本発明のポリ乳酸系繊維において両重合体の溶融粘度が上記式を満足する必要性は、繊維を製造するに際して最も安定な状態で製糸するためであり、具体的にはＭＦＲ（Ｂ）をＭＦＲ（Ａ）よりも小さくすることで、繊維表面に位置する重合体Ｂの繊維配向を高めて繊維間の密着を防止しつつ、実用上問題がないような耐久性のある熱バインダー性能を得るために好ましいからである。ＭＦＲ（Ａ）が５ｇ／１０分未満あるいはＭＦＲ（Ｂ）が５ｇ／１０分未満であると、繊維を溶融紡糸するに際して曳糸性が著しく低下する。曳糸性を改良するために紡糸温度を上げると、紡糸口金近傍で発煙が増加して紡糸環境を悪化したり、また糸切れが増加するので好ましくない。一方、ＭＦＲ（Ａ）が１００ｇ／１０分を超えると、あるいはＭＦＲ（Ｂ）が８０ｇ／１０分を超えると、繊維強度が低下したり、耐久性が低下したりして、実用範囲が狭くなるので好ましくない。したがって、本発明では、両重合体の溶融粘度を上式を満足する範囲とするが、好ましくは８≦ＭＦＲ（Ａ）≦８０、６≦ＭＦＲ（Ｂ）≦６０、かつＭＦＲ（Ｂ）をＭＦＲ（Ａ）よりも２ｇ／１０分以上低くし、より好ましくは１０≦ＭＦＲ（Ａ）≦６０、８≦ＭＦＲ（Ｂ）≦５０、かつＭＦＲ（Ｂ）をＭＦＲ（Ａ）よりも５ｇ／１０分以上低くするのがよい。 In the polylactic acid fiber of the present invention, the melt viscosity of the two types of polylactic acid polymers A and B, that is, the melt flow rate value MFR (A) of the polymer A constituting the fiber of the present invention and the polymer B It is necessary that the melt flow rate value MFR (B) of the above satisfies the above formulas ( 1 ) to ( 3 ). In the polylactic acid fiber of the present invention, the necessity of satisfying the above formula for the melt viscosity of both polymers is to produce the yarn in the most stable state when producing the fiber. Specifically, MFR (B) is converted to MFR. In order to obtain durable thermal binder performance with no practical problems while increasing the fiber orientation of the polymer B located on the fiber surface to prevent adhesion between the fibers by making it smaller than (A) This is because it is preferable. When the MFR (A) is less than 5 g / 10 minutes or the MFR (B) is less than 5 g / 10 minutes, the spinnability is remarkably lowered when the fiber is melt-spun. Increasing the spinning temperature in order to improve the spinnability is not preferable because smoke is increased in the vicinity of the spinneret and the spinning environment is deteriorated or yarn breakage is increased. On the other hand, if the MFR (A) exceeds 100 g / 10 minutes, or if the MFR (B) exceeds 80 g / 10 minutes, the fiber strength decreases or the durability decreases, and the practical range becomes narrow. Therefore, it is not preferable. Therefore, in the present invention, the melt viscosity of both polymers is set to a range satisfying the above formula, but preferably 8 ≦ MFR (A) ≦ 80, 6 ≦ MFR (B) ≦ 60, and MFR (B) is set to MFR. 2 g / 10 min or less than (A), more preferably 10 ≦ MFR (A) ≦ 60, 8 ≦ MFR (B) ≦ 50, and MFR (B) is 5 g / 10 min than MFR (A). It is better to make it lower.
また、本発明のポリ乳酸系繊維では、ポリ乳酸系の重合体Ｂが繊維表面の一部に露出する如く複合されていることが必要である。これは、光学純度の低い成分にバインダー機能を発現させるために不可決のためである。すなわち、繊維表面に露出することで、容易に他の繊維または素材との接触点で接着可能となる。なお、繊維表面の一部に露出する如き複合断面形状としては、例えば図１（ａ）〜同図（ｋ）に示すような丸断面、異形断面、中空断面、芯鞘型、偏心芯鞘型、並列型、海島型、多層型、多芯型、放射分割型、点対称分割型など、各種の分割型複合断面であり、これらは必ずしも同種である必要はなく、異種の組み合わせであってもよい。この繊維において、前記溶融粘度差及び光学純度に大きな差がある組み合わせを選択し、並列型、偏心芯鞘型、偏心分割型等の複合繊維を形成すると、光学純度の低い重合体が熱接着成分として寄与するばかりでなく、収縮成分としても機能して捲縮発現能力を具備できる。 In the polylactic acid fiber of the present invention, it is necessary that the polylactic acid polymer B is composited so as to be exposed on a part of the fiber surface. This is because it is impossible to develop a binder function in a component having low optical purity. That is, by being exposed on the fiber surface, it is possible to easily bond at a contact point with another fiber or material. In addition, as a composite cross-sectional shape exposed to a part of the fiber surface, for example, as shown in FIGS. 1 (a) to (k), a round cross-section, a modified cross-section, a hollow cross-section, a core-sheath type, an eccentric core-sheath type , Parallel type, sea-island type, multi-layer type, multi-core type, radial division type, point symmetry division type, etc., and various division type composite cross-sections, these do not necessarily need to be the same type, Good. In this fiber, when a combination having a large difference in melt viscosity and optical purity is selected, and a composite fiber such as a parallel type, an eccentric core-sheath type, or an eccentric split type is formed, a polymer having a low optical purity becomes a thermal bonding component. In addition, it can function as a contraction component and can have a crimp expression ability.
さらに、本発明のポリ乳酸系繊維では、ポリ乳酸系重合体Ｂは光学純度の低いものであり、純度が低いほど、熱接着性が向上する。特に、この重合体Ｂは、一般的に低分子量物が多く、軟化点や融点が低く、結晶化し難いため、繊維間に密着が発生しやすい。それを防止すべく、適宜、結晶核剤、例えばタルク、炭酸カルシウム、酸化チタンなどを少量添加することが好ましい。結晶核剤を添加することで、繊維表面の重合体の結晶化が促進され、溶融紡糸した時の密着防止ばかりでなく、熱延伸するに際しても繊維間の密着を防止することが可能となる。また、結晶核剤は粒径が数μｍ以下の微粒子のものを採用するのが好ましく、粒径が大き過ぎると、溶融紡糸時に紡糸口金装置において濾圧上昇が生じたり、あるいは糸切れが生じたりするからである。結晶核剤が微粒子のものであると、繊維表面の梨地化効果すなわち繊維−繊維間あるいは繊維−金属間の摩擦係数を低下させる効果が発現し、布帛形成時の操業性を向上させることができる。なお、本発明においては、前述したところのポリ乳酸を主成分とする重合体に対し、必要に応じて例えば熱安定剤、結晶核剤、艶消し剤、顔料、耐光剤、耐候剤、酸化防止剤、抗菌剤、香料、可塑剤、染料、界面活性剤、表面改質剤、各種無機及び有機電解質、微粉体、難燃剤等の各種添加剤を、本発明の作用効果を損なわない範囲内で添加することができる。 Furthermore, in the polylactic acid fiber of the present invention, the polylactic acid polymer B has a lower optical purity, and the lower the purity, the better the thermal adhesiveness. In particular, this polymer B generally has many low molecular weight substances, has a low softening point and a low melting point, and is difficult to crystallize, so that adhesion between fibers tends to occur. In order to prevent this, it is preferable to add a small amount of a crystal nucleating agent such as talc, calcium carbonate, titanium oxide or the like as appropriate. By adding a crystal nucleating agent, crystallization of the polymer on the fiber surface is promoted, and it becomes possible not only to prevent adhesion when melt-spun, but also to prevent adhesion between fibers during hot drawing. The crystal nucleating agent is preferably a fine particle having a particle size of several μm or less. If the particle size is too large, an increase in filtration pressure may occur in the spinneret device during melt spinning, or thread breakage may occur. Because it does. When the crystal nucleating agent is a fine particle, a satin-finishing effect on the fiber surface, that is, an effect of reducing the friction coefficient between the fiber and the fiber or between the fiber and the metal is exhibited, and the operability during the formation of the fabric can be improved. . In the present invention, for the polymer having polylactic acid as a main component as described above, for example, a heat stabilizer, a crystal nucleating agent, a matting agent, a pigment, a light-resistant agent, a weather-resistant agent, an antioxidant, as necessary. Various additives such as additives, antibacterial agents, fragrances, plasticizers, dyes, surfactants, surface modifiers, various inorganic and organic electrolytes, fine powders, flame retardants, and the like within the range that does not impair the effects of the present invention. Can be added.
本発明のポリ乳酸系繊維は、その単繊維繊度が０．３〜１００デニ−ルであるのが好ましい。単繊維繊度が０．３デニ−ル未満となると、繊維を溶融紡糸するに際して紡糸口金孔の精度向上や固化点の制御、吐出量の低減に伴う生産性の低下、糸切れが発生し易くなる等の問題が生じ、好ましくない。一方、単繊維繊度が１００デニールを超えると、通常の短繊維を製造する工程では紡糸や延伸が困難で、別途、特殊な製造設備が必要となり、高コストとなるので好ましくない。 The polylactic acid fiber of the present invention preferably has a single fiber fineness of 0.3 to 100 denier. When the single fiber fineness is less than 0.3 denier, when the fiber is melt-spun, the accuracy of the spinneret hole is improved, the solidification point is controlled, the productivity is lowered due to the reduction of the discharge amount, and yarn breakage is likely to occur. Such a problem occurs, which is not preferable. On the other hand, when the single fiber fineness exceeds 100 deniers, spinning and drawing are difficult in the process of producing ordinary short fibers, and a special production facility is separately required, resulting in high costs.
本発明のポリ乳酸系繊維は、その繊維長として一般的に１〜１００ｍｍが好適である。繊維長が短いと、カード通過時に脱落綿が増え、操業性の低下や不織布とした場合に強力の低下がある。また、繊維長が２５ｍｍ以下の場合には、一般に、湿式不織布用に展開する。繊維長が短いほど単繊維への分散性が向上するので好ましいが、極度に短過ぎると、本来の繊維特性が不織布において発現しない恐れが生じる。一方、繊維長が余りにも長いと、カード通過性が低下したり、ネツプが発生し易くなる。したがって、繊維長としては、上記の観点から総合的に適正な長さを選定する。 In general, the polylactic acid fiber of the present invention preferably has a fiber length of 1 to 100 mm. When the fiber length is short, falling cotton increases when passing through the card, and there is a decrease in operability and strength when the nonwoven fabric is used. When the fiber length is 25 mm or less, the fiber length is generally developed for a wet nonwoven fabric. A shorter fiber length is preferable because dispersibility into single fibers is improved. However, if the fiber length is too short, the original fiber characteristics may not be exhibited in the nonwoven fabric. On the other hand, if the fiber length is too long, the card passing property is deteriorated and nesting is likely to occur. Therefore, the fiber length is selected comprehensively from the above viewpoint.
本発明のポリ乳酸系繊維は、その繊維強度が０．５ｇ／ｄ以上のものであるのが好ましい。強度が０．５ｇ／ｄ未満では、実用面で強力不足という問題が生じる恐れがある。繊維強度は高いほど実用範囲が広がることから好ましいが、その用途に応じて適宜設計すればよい。また、その伸度は、特に限定するものではないが、通常、１５〜８０％が好ましい。伸度が１５％未満になると、糸切れが生じたり延伸操業性が低下する問題が生じ、一方、伸度が８０％を超えると、通常の布帛を形成した後の寸法安定性が低下することがあり、好ましくない。なお、この繊維を成形用途に採用する場合には、高伸度であるほど成形加工性が向上するため、好ましい。 The polylactic acid fiber of the present invention preferably has a fiber strength of 0.5 g / d or more. If the strength is less than 0.5 g / d, there may be a problem of insufficient strength in practical use. Higher fiber strength is preferable because the practical range is widened, but it may be appropriately designed according to the application. Further, the elongation is not particularly limited, but is usually preferably 15 to 80%. If the elongation is less than 15%, there is a problem that yarn breakage or stretching operability is deteriorated. On the other hand, if the elongation exceeds 80%, the dimensional stability after forming a normal fabric is degraded. Is not preferable. In addition, when employ | adopting this fiber for a shaping | molding use, since a moldability improves, so that a high elongation is preferable.
本発明のポリ乳酸系繊維は、単独または他の繊維と混用して、紡績糸、紐、それらからなる織物、編物、各種不織布すなわちサーマルスルー不織布、エンボス加工不織布、ニードルパンチ不織布、スパンレース不織布、湿式不織布など、また複合材料その他の繊維構造物の製造に用いることができる。他の繊維と混用する場合には、ポリエステル繊維、ナイロン繊維、アクリル繊維、ビニロン繊維、ポリプロピレン繊維、ポリエチレン繊維などの繊維形成性熱可塑性重合体からなる合成繊維、レーヨン、ポリノジツク、リヨセル、テンセルなどの再生繊維、アセテートなどの半合成繊維、また羊毛、絹、木綿、麻、木材パルプなどの天然繊維が採用される。そしてその中でも、前記再生繊維、半合成繊維、天然繊維、脂肪肪族ポリエステルからなる繊維などの生分解性繊維と混用すれば、完全に生分解可能な製品が得られるため、特に好ましい。 The polylactic acid fiber of the present invention is used alone or in combination with other fibers, spun yarn, string, woven fabric, knitted fabric, various nonwoven fabrics, that is, thermal through nonwoven fabric, embossed nonwoven fabric, needle punched nonwoven fabric, spunlace nonwoven fabric, It can be used for the production of wet nonwoven fabrics, composite materials and other fiber structures. When mixed with other fibers, polyester fibers, nylon fibers, acrylic fibers, vinylon fibers, polypropylene fibers, synthetic fibers made of a fiber-forming thermoplastic polymer such as polyethylene fibers, rayon, polynosic, lyocell, tencel, etc. Recycled fibers, semi-synthetic fibers such as acetate, and natural fibers such as wool, silk, cotton, hemp, and wood pulp are used. Among them, it is particularly preferable to mix with biodegradable fibers such as the regenerated fibers, semi-synthetic fibers, natural fibers, and aliphatic polyester fibers, since a completely biodegradable product can be obtained.
次に、本発明のポリ乳酸系複合短繊維からなる不織布について説明する。本発明のポリ乳酸系複合短繊維からなる不織布は、前記構成の複合短繊維を少なくとも１０重量％含有し、該短繊維で熱接着されて形態が保持されていることが好ましい。前記構成の繊維を少なくとも１０重量％含有する理由は、不織布の形態を保持するために不可欠な熱バインダー性能を具備するためであり、そのために該短繊維を１０重量％以上とすることが好ましい。上限は特に限定するものではなく、この繊維１００％であってもよく、目的、用途に応じた混合比率を選定すればよい。混合する他の繊維も特に限定されず、合成繊維、半合成繊維、再生繊維、天然繊維でもよいが、最も好ましいのは前述した半合成繊維、再生繊維、天然繊維または脂肪族ポリエステル繊維などの生分解性繊維であり、これらと混用すれば、完全に生分解可能な製品が得られるため、特に好ましい。 Next, the nonwoven fabric which consists of the polylactic acid-type composite short fiber of this invention is demonstrated. Nonwoven fabric made of polylactic acid-based composite short fiber of the present invention, the composite staple fibers of the structure contains at least 10 wt%, it is preferable to form are thermally bonded is held by the short fibers. The reason for containing at least 10% by weight of the fiber having the above-mentioned constitution is to provide a thermal binder performance that is indispensable for maintaining the form of the nonwoven fabric. For this reason, the short fiber is preferably made 10% by weight or more. The upper limit is not particularly limited, and may be 100% of this fiber, and a mixing ratio may be selected according to the purpose and application. Other fibers to be mixed are not particularly limited, and may be synthetic fibers, semi-synthetic fibers, regenerated fibers, or natural fibers, but most preferable are raw fibers such as the above-described semi-synthetic fibers, regenerated fibers, natural fibers, or aliphatic polyester fibers. It is a degradable fiber, and if it is mixed with these, a completely biodegradable product is obtained, which is particularly preferable.
次に、本発明のポリ乳酸系複合短繊維及びその短繊維からなる不織布を製造するための方法を説明するが、本発明の方法は、この方法に限ったものでないことは言うまでもない。本発明のポリ乳酸系複合短繊維は、公知の溶融複合紡糸装置による紡糸方法及び延伸方法により容易に製造することができる。すなわち、ポリ乳酸系複合短繊維を構成する重合体として相互に光学純度の異なる２種の重合体を選択し、この重合体を個別に溶融計量し、光学純度の低い重合体を繊維表面に配する複合紡糸口金装置から繊維を溶融紡出し、冷却し、巻取った後数十万デニールのトウとして延伸するか、または巻取ることなく数千以上のデニールに集束させた未延伸糸ケンスとし、これをさらに集束して熱延伸し、スタツフアボツクスによる捲縮を付与した後、仕上げ油剤を付与、乾燥した後、所定長に切断することによって、本発明の短繊維を製造する。ここで、熱延伸とは、該繊維をガラス転移温度以上かつ軟化温度以下の温度で繊維を延伸することをいう。溶融紡糸に際しては、巻取り速度が１００〜２０００ｍ／分の低速紡糸、巻取り速度が２０００〜５０００ｍ／分の高速紡糸、巻取り速度が５０００ｍ／分以上の超高速紡糸が可能であり、紡糸と延伸を連続して行ういわゆるスピンドロー方式も好ましく採用できる。スピンドロー方式で得た繊維は、適度な繊度にした後、更なる延伸をせずに捲縮加工をすることもできる。本発明でいう熱延伸とは、重合体のガラス転移温度以上の温度で延伸することを意味し、一般の多段延伸においては、第１ローラーや第２ローラー等の加熱、第１ローラーと第２ローラーとの間、あるいは第２ローラーと第３ローラーとの間、あるいは各ローラー間の両方で熱板やスチームあるいは温水等を加熱媒体として用いて延伸する。必要に応じて、最終ローラー以降の工程で、熱処理を行うこともある。これらの加熱については、紡糸工程と延伸工程とを直結する製法、いわゆるスピンドロー法においても、同様である。熱延伸するに際し、その延伸時の温度には当然ながら上限があり、採用する重合体の中で光学純度の低い重合体の軟化温度未満とする必要がある。これは、延伸をする上では、被延伸繊維糸条の密着や融着を防止しなければならないからである。 Next, a method for producing the polylactic acid-based composite short fiber of the present invention and a nonwoven fabric composed of the short fiber will be described. Needless to say, the method of the present invention is not limited to this method. The polylactic acid-based composite short fiber of the present invention can be easily produced by a spinning method and a drawing method using a known melt composite spinning apparatus. That is, two types of polymers having different optical purities are selected as the polymers constituting the polylactic acid-based composite short fiber, and these polymers are individually melt-metered to distribute the polymer having a low optical purity on the fiber surface. The fiber is melt spun from a composite spinneret device, cooled, wound, and then stretched as hundreds of thousands of denier tows, or unstretched yarn cans that are bundled into thousands of deniers without being wound, This is further converged and hot-drawn to give crimps by means of a stuff box, then a finishing oil is applied, dried, and then cut to a predetermined length to produce the short fiber of the present invention. Here, hot drawing refers to drawing the fiber at a temperature not lower than the glass transition temperature and not higher than the softening temperature. In melt spinning, low speed spinning with a winding speed of 100 to 2000 m / min, high speed spinning with a winding speed of 2000 to 5000 m / min, and ultra-high speed spinning with a winding speed of 5000 m / min or more are possible. A so-called spin draw method in which stretching is continuously performed can also be preferably employed. The fiber obtained by the spin draw method can be crimped without further drawing after having an appropriate fineness. The term “thermal stretching” as used in the present invention means stretching at a temperature equal to or higher than the glass transition temperature of the polymer. In general multi-stage stretching, heating the first roller and the second roller, the first roller and the second roller. Stretching is performed using a hot plate, steam, hot water or the like as a heating medium between the rollers, between the second roller and the third roller, or between each roller. If necessary, heat treatment may be performed in the steps after the final roller. The same applies to the heating in the production method in which the spinning step and the drawing step are directly connected, that is, the so-called spin draw method. In the heat stretching, the temperature during the stretching naturally has an upper limit, and it is necessary to make it lower than the softening temperature of the polymer having low optical purity among the employed polymers. This is because, when drawing, it is necessary to prevent adhesion and fusion of the drawn fiber yarns.
次に、本発明のポリ乳酸系複合短繊維からなる不織布は、公知の短繊維不織布製造装置を用いる乾式あるいは湿式の不織布製造方法により容易に製造することができる。すなわち、前記方法で得た短繊維をホツパーにて計量後他の繊維とブレンドするか、あるいは単独で開繊機にて予備開繊し、その後、カード機を用いてウエブを形成する。カード機は、必要に応じてパラレル機、セミランダム機、ランダム機を適宜採用する。得られた繊維ウエブを、繊維を構成する光学純度の最も低い重合体の軟化点以上かつ光学純度の最も高い重合体の融点未満で熱接着することによって、乾式不織布を製造することができる。熱接着させる方法としては、熱風循環型乾燥機、熱風貫流型乾燥機、サクシヨンドラム型乾燥機、ヤンキードラム型乾燥機、加熱フラツトカレンダ−機、加熱エンボス加工機などを用いる。なお、ウエブを形成後、ニードルパンチ法やスパンレース法で簡易に繊維同士を交絡させ形態保持した後、熱処理を施して熱接着させてもよい。一方、湿式不織布においては、前記方法で得たシヨートカツト綿の繊維を計量後他のシヨートカツト綿の繊維とブレンドするか、あるいは単独で離解機に投入し、繊維を良く離解させた後、抄紙機に移行させ、適度な繊維濃度で抄紙する。抄紙したウエブは、脱水した後、乾燥機にて乾燥すると共にポリ乳酸系短繊維を構成する光学純度の最も低い重合体の軟化点以上かつ光学純度の最も高い重合体の融点未満で熱接着することによって、湿式不織布を製造することができる。本発明の不織布では、前記ポリ乳酸系短繊維同士の接触点で、またはポリ乳酸系短繊維が介在する部位で、繊維間を熱融着させることが必要である。このことにより、不織布の強力が向上すると共に、繰り返し応力にも耐え、極めて実用的な不織布を得ることができる。 Next, the nonwoven fabric comprising the polylactic acid-based composite short fibers of the present invention can be easily produced by a dry or wet nonwoven fabric production method using a known short fiber nonwoven fabric production apparatus. That is, the short fibers obtained by the above method are weighed with a hopper and blended with other fibers, or preliminarily opened with a spreader alone, and then a web is formed using a card machine. As the card machine, a parallel machine, a semi-random machine, and a random machine are appropriately adopted as necessary. A dry nonwoven fabric can be produced by thermally bonding the obtained fiber web at a temperature equal to or higher than the softening point of the polymer having the lowest optical purity and less than the melting point of the polymer having the highest optical purity. As a heat bonding method, a hot-air circulating dryer, a hot-air once-through dryer, a succession drum dryer, a Yankee drum dryer, a heating flat calendar machine, a heating embossing machine, or the like is used. In addition, after forming the web, the fibers may be easily entangled with each other by a needle punch method or a spun lace method, and the shape may be maintained, and then heat treatment may be performed for thermal bonding. On the other hand, in wet non-woven fabric, the fibers of the short cut cotton obtained by the above method are weighed and blended with other short cut cotton fibers, or they are put alone into the disaggregator and the fibers are thoroughly disaggregated, and then the paper machine. Transfer and make paper with moderate fiber concentration. The paper-made web is dehydrated, dried in a drier, and heat-bonded at a temperature above the softening point of the polymer with the lowest optical purity and the melting point of the polymer with the highest optical purity. Thus, a wet nonwoven fabric can be produced. In the nonwoven fabric of the present invention, it is necessary to thermally bond the fibers at the contact point between the polylactic acid-based short fibers or at the site where the polylactic acid-based short fibers are interposed. As a result, the strength of the nonwoven fabric can be improved, and it can withstand repeated stress, and an extremely practical nonwoven fabric can be obtained.
本発明の不織布の目付は、特に限定されるものではなく、１０ｇ／ｍ2 程度の比較的低目付から、厚さが５ｍｍ以上で特に１５０ｍｍ以上のいわゆる固綿と称される２０００ｇ／ｍ2 程度までのものも包含するものである。 Basis weight of the nonwoven fabric of the present invention is particularly not limited, 10 g / m 2 about a relatively low basis weight, thickness and particularly referred 2000 g / m 2 about a 150mm or more so-called Katawata above 5mm Including those up to.
次に、実施例に基づいて本発明を具体的に説明する。なお、各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。
融点１（℃）：パ−キンエルマー社製示差走査型熱量計ＤＳＣ−２型を用い、重合体約５ｍｇを試料とし、窒素雰囲気中で、昇温速度１０℃／分、温度２００℃で５分間ホールドした後、降温速度１０℃／分で温度２０℃まで降温し、再び昇温速度１０℃／分で温度２００℃まで昇温させた時の最大融解発熱ピーク温度を融点（以下、Ｔｍ１という。）とした。
ガラス転移温度（℃）：上記融点Ｔｍ１を測定する際に得られる初期発熱ピーク温度をガラス転移温度（以下、Ｔｇという。）とした。
結晶化温度（℃）：上記融点Ｔｍ１を測定する際に得られる吸熱ピーク温度を結晶化温度（以下、Ｔｃという。）とした。
融点２（℃）：ＪＩＳ Ｌ−１０１５に記載のＡ法に準じ、偏光装置及び加熱装置を備えた載物台付顕微鏡を用いて、繊維の溶融温度（以下、Ｔｍ２という。）を測定し、融点２とした。
ＭＦＲ（ｇ／１０分）：ＡＳＴＭ Ｄ１２３８に準じ、温度２１０℃、印加荷重２１６０ｇの条件下で測定した。
短繊維の単繊維繊度（ｄ）：ＪＩＳ Ｌ−１０１５に準じて測定した。
短繊維の強度（ｇ／ｄ）及び伸度（％）：ＪＩＳ Ｌ−１０１５に準じ、試料の把持間隔２ｃｍ、引張り速度２ｃｍ／分の条件下で伸長した時の最大引張強さ（ｇ）を単繊維繊度で除した値の平均値を強度（ｇ／ｄ）とし、またその時の伸び率の平均値を伸度（％）とした。
短繊維の捲縮数（個／２５ｍｍ）、捲縮率（％）及び熱水収縮率（％）：ＪＩＳ Ｌ−１０１５に準じて測定した。
短繊維の生分解性：試料を土中に埋設して２年経過後に取り出し、繊維形態が保持されていない場合、あるいはその形態は保持しているものの引張り強力の保持率が埋設前の強力の５０％以下に低下している場合、分解性が良好であると評価した。
Next, the present invention will be specifically described based on examples. In addition, the measurement and evaluation of various characteristics in each Example were implemented by the following method.
Melting point 1 (° C.): Using a differential scanning calorimeter DSC-2 manufactured by Perkin Elmer, using about 5 mg of a polymer as a sample, heating rate of 10 ° C./min in a nitrogen atmosphere, 5 at a temperature of 200 ° C. After holding for a minute, the maximum melting exothermic peak temperature when the temperature is lowered to a temperature of 20 ° C. at a temperature lowering rate of 10 ° C./min, and again raised to a temperature of 200 ° C. at a temperature rising rate of 10 ° C./min .)
Glass transition temperature (° C.): The initial exothermic peak temperature obtained when measuring the melting point Tm1 was defined as the glass transition temperature (hereinafter referred to as Tg).
Crystallization temperature (° C.): The endothermic peak temperature obtained when measuring the melting point Tm1 was defined as the crystallization temperature (hereinafter referred to as Tc).
Melting point 2 (° C.): In accordance with method A described in JIS L-1015, the melting temperature of the fiber (hereinafter referred to as Tm2) was measured using a microscope with a mounting table equipped with a polarizing device and a heating device. The melting point was 2.
MFR (g / 10 min): Measured according to ASTM D1238 under conditions of a temperature of 210 ° C. and an applied load of 2160 g.
Single fiber fineness (d) of short fibers: measured according to JIS L-1015.
Strength (g / d) and elongation (%) of short fiber: Maximum tensile strength (g) when stretched under the conditions of 2 cm / min of the holding distance of the sample and 2 cm / min in accordance with JIS L-1015. The average value divided by the single fiber fineness was defined as strength (g / d), and the average value of elongation at that time was defined as elongation (%).
The number of crimps of short fibers (pieces / 25 mm), crimp rate (%), and hot water shrinkage rate (%): measured according to JIS L-1015.
Biodegradability of short fibers: The sample is buried in the soil and taken out after 2 years. If the fiber form is not retained, or the form is retained, the tensile strength retention rate is strong before embedding. When it decreased to 50% or less, it was evaluated that the decomposability was good.
不織布の目付（ｇ／ｍ2 ）：標準状態の試料から縦１０ｃｍ×横１０ｃｍの試料片を１０点準備し、平衡水分に至らしめた後、各試料片の重量を秤量し、得られた値の平均値を単位面積当たりに換算し、目付（ｇ／ｍ2 ）とした。
ウエブの熱接着性：ウエブの熱接着性を、辻井染機株式会社製連続熱処理機ＭＦＤ−３５０Ｅ型にウエブを通し、次の４段階で評価した。
◎：短繊維同士がその接触部で強固に熱融着している。
○：短繊維同士がその接触部で熱融着している。
△：短繊維同士がその接触部で一部熱融着している。
×：短繊維同士がその接触部で熱融着していない。
不織布の引張り強力（ｋｇ／５ｃｍ幅）：ＪＩＳ Ｌ−１０９６に記載のストリツプ法に準じて測定した。すなわち、試料幅５ｃｍ、試料長２０ｃｍの試料片を１０個準備し、定速伸張型引張試験機（東洋ボ−ルドウイン社製テンシロンＵＴＭ−４−１−１００）を用いて、把持間隔１０ｃｍ、引張り速度１０ｃｍ／分の条件下で伸長した時の最大引張り強さ（ｋｇ）の平均値を引張り強力（ｋｇ／５ｃｍ幅）とした。なお、この引張り強力の測定は、不織布の縦方向（以下、ＭＤという。）と横方向（以下、ＣＤという。）のそれぞれについて実施した。
不織布の厚さ（ｍｍ）：大栄科学精機製作所製の厚み測定機を用い、印加荷重４．５ｇ／ｃｍ2 の条件下で１０秒間経過した時点の厚さ（ｍｍ）を測定した。
不織布の嵩密度（ｇ／ｃｍ3 ）：上記目付（ｇ／ｍ2 ）と厚さ（ｍｍ）から、下記式で嵩密度（ｇ／ｃｍ3 ）を算出した。
嵩密度（ｇ／ｃｍ3 ）＝目付（ｇ／ｍ2 ）／厚さ（ｍｍ）／１０００不織布の強力保持率ＴＡ（％）：不織布強力Ｔ１（ｋｇ／２．５ｃｍ幅）が明確な不織布試料片を用い、上記嵩高性保持率の測定法と同様にして繰り返し圧縮試験を行った後の不織布強力Ｔ２（ｋｇ／２．５ｃｍ幅）を測定し、下記式で強力保持率ＴＡ（％）を求めた。
ＴＡ（％）＝（Ｔ２／Ｔ１）×１００不織布の嵩高性保持率ＤＡ（％）：繰り返し圧縮時の嵩高性保持率を次の方法によって求めた。すなわち、厚さＤ１（ｍｍ）を測定した不織布試料片（１０ｃｍ×１０ｃｍ）を平行平面板に挟み、印加荷重５ｋｇの条件下で合計１００回の繰り返し圧縮試験を行った後の厚さＤ２（ｍｍ）を測定し、下記式で嵩高性保持率ＤＡ（％）を求めた。
ＤＡ（％）＝（Ｄ２／Ｄ１）×１００不織布の生分解性：試料を土中に埋設して２年経過後に取り出し、不織布形態が保持されていない場合、あるいはその形態は保持しているものの引張り強力の保持率が埋設前の強力の５０％以下に低下している場合、分解性が良好であると評価した。
Non-woven fabric basis weight (g / m 2 ): 10 pieces of 10 cm long × 10 cm wide sample pieces were prepared from the standard sample, and after reaching the equilibrium moisture, the weight of each sample piece was weighed. The average value was converted per unit area and used as the basis weight (g / m 2 ).
Thermal adhesiveness of web: The thermal adhesiveness of the web was evaluated in the following four stages by passing the web through a continuous heat treatment machine MFD-350E manufactured by Sakurai Dyeing Co., Ltd.
A: Short fibers are strongly heat-sealed at the contact portion.
○: Short fibers are heat-sealed at the contact portion.
Δ: Short fibers are partially heat-sealed at the contact portion.
X: Short fibers are not heat-sealed at the contact portion.
Tensile strength (kg / 5 cm width) of nonwoven fabric: Measured according to the strip method described in JIS L-1096. That is, 10 sample pieces having a sample width of 5 cm and a sample length of 20 cm were prepared, and using a constant speed extension type tensile tester (Tensilon UTM-4-1-100 manufactured by Toyo Boldwin Co., Ltd.) The average value of the maximum tensile strength (kg) when stretched at a speed of 10 cm / min was defined as the tensile strength (kg / 5 cm width). The tensile strength was measured in each of the longitudinal direction (hereinafter referred to as MD) and the lateral direction (hereinafter referred to as CD) of the nonwoven fabric.
Thickness (mm) of the nonwoven fabric: Using a thickness measuring machine manufactured by Daiei Kagaku Seisakusho, the thickness (mm) at the time when 10 seconds passed was measured under the condition of an applied load of 4.5 g / cm 2 .
Bulk density (g / cm 3 ) of the nonwoven fabric: From the basis weight (g / m 2 ) and thickness (mm), the bulk density (g / cm 3 ) was calculated by the following formula.
Bulk density (g / cm 3 ) = Weight per unit area (g / m 2 ) / Thickness (mm) / 1000 Nonwoven fabric strength retention TA (%): Nonwoven fabric sample with clear nonwoven fabric strength T1 (kg / 2.5 cm width) Using a piece, the nonwoven fabric strength T2 (kg / 2.5 cm width) after repeated compression tests in the same manner as in the above bulkiness retention measurement method was measured, and the strength retention TA (%) was calculated by the following formula. Asked.
TA (%) = (T2 / T1) × 100 Bulkiness retention rate of nonwoven fabric DA (%): The bulkiness retention rate during repeated compression was determined by the following method. That is, the thickness D2 (mm) after a nonwoven fabric sample piece (10 cm × 10 cm) whose thickness D1 (mm) was measured was sandwiched between parallel flat plates and subjected to a total of 100 repeated compression tests under the condition of an applied load of 5 kg. ) And the bulkiness retention DA (%) was determined by the following formula.
DA (%) = (D2 / D1) × 100 Biodegradability of non-woven fabric: When the sample is buried in the soil and taken out after 2 years and the non-woven fabric form is not retained, or the form is retained When the tensile strength retention was reduced to 50% or less of the strength before embedding, it was evaluated that the decomposability was good.
実施例１
光学純度が９９％、ＭＦＲ（Ａ）が２５ｇ／１０分、ガラス転移温度Ｔｇが６０℃、結晶化温度Ｔｃが１３６℃、融点Ｔｍ１が１７０℃のポリＬ−乳酸樹脂を芯成分の重合体Ａとし、一方、光学純度が９０％、ＭＦＲ（Ｂ）が１５ｇ／１０分、ガラス転移温度Ｔｇが５８℃、結晶化温度Ｔｃと融点Ｔｍ１を示さないポリＬ−乳酸樹脂を鞘成分の重合体Ｂとして、溶融紡糸を行った。すなわち、単軸のエクストルーダー型溶融押出し機２台を備えた複合紡糸装置を用い、直径０．４ｍｍ、孔数１８０個の紡糸孔を有する紡糸口金より紡糸温度２１０℃、単孔吐出量１．０ｇ／分、芯／鞘複合比（重量比）＝１／１で溶融紡出し、空気冷却装置にて冷却、油剤付与をしながら紡糸速度１１００ｍ／分で巻取って未延伸糸を得た。得られた未延伸糸をリワインドして、２２万デニールの未延伸糸トウを形成した。次いで、一般的に用いられている２段延伸が可能の多段熱延伸装置を用い、未延伸糸トウを延伸した。延伸に際しては、１段目の延伸倍率と２段目の延伸倍率との比を１．４／１、第１ローラー温度を６０℃、第２ローラー温度を９０℃、第３ローラーを非加熱、第１ローラーと第２ローラーとの間の温浴バス温度を７０℃とし、全延伸倍率を２．２とした。延伸に引き続き、スタツフアボツクスを用いて捲縮を付与した後、仕上げ油剤を付与し、低温での乾燥後、５１ｍｍ長に繊維を切断して、短繊維を得た。得られた短繊維は、単繊維繊度が４．０ｄ、強度が３．５ｇ／ｄ、伸度が３５％、温度８０℃における乾熱収縮率が２％、捲縮数が１３個／２５ｍｍ、捲縮率が１３％で、繊維間の密着もないものであった。複屈折率△ｎを調査すると、芯成分が３０×１０-3、鞘成分が２１×１０-3、融点Ｔｍ２を調査すると、芯成分が１７０℃、鞘成分が１２０℃であった。この繊維を、温度１３０℃の熱風乾燥機を用い５分間熱処理したところ、単繊維間が強固に融着され、熱バインダー性能に優れることが分かった。この短繊維は、土中に埋設して生分解性を評価したところ、良好なものであった。
Example 1
Polymer A having a core component of poly L-lactic acid resin having an optical purity of 99%, MFR (A) of 25 g / 10 min, glass transition temperature Tg of 60 ° C., crystallization temperature Tc of 136 ° C. and melting point Tm1 of 170 ° C. On the other hand, polymer sheath B is a poly L-lactic acid resin having an optical purity of 90%, MFR (B) of 15 g / 10 min, a glass transition temperature Tg of 58 ° C., and having no crystallization temperature Tc and melting point Tm1. As a result, melt spinning was performed. That is, using a composite spinning apparatus equipped with two single-screw extruder type melt extruders, a spinning temperature of 210 ° C. and a single-hole discharge rate of 1. from a spinneret having a spinning hole with a diameter of 0.4 mm and a number of holes of 180. Melt spinning was performed at a core / sheath composite ratio (weight ratio) = 1/1 at 0 g / min, and wound at a spinning speed of 1100 m / min while cooling with an air cooling device and applying an oil agent to obtain an undrawn yarn. The obtained undrawn yarn was rewound to form a 220,000 denier undrawn yarn tow. Subsequently, the undrawn yarn tow was drawn using a generally used multi-stage heat drawing apparatus capable of two-stage drawing. At the time of stretching, the ratio of the draw ratio of the first stage to the draw ratio of the second stage is 1.4 / 1, the first roller temperature is 60 ° C., the second roller temperature is 90 ° C., the third roller is not heated, The bath temperature between the first roller and the second roller was 70 ° C., and the total draw ratio was 2.2. Subsequent to stretching, crimping was performed using Stat Avox, a finishing oil was applied, and after drying at low temperature, the fiber was cut into 51 mm lengths to obtain short fibers. The obtained short fiber has a single fiber fineness of 4.0 d, a strength of 3.5 g / d, an elongation of 35%, a dry heat shrinkage rate of 2% at a temperature of 80 ° C., a crimp number of 13/25 mm, The crimp rate was 13%, and there was no adhesion between the fibers. When the birefringence Δn was investigated, the core component was 30 × 10 −3 , the sheath component was 21 × 10 −3 , and the melting point Tm2 was examined. The core component was 170 ° C. and the sheath component was 120 ° C. When this fiber was heat-treated for 5 minutes using a hot air drier at a temperature of 130 ° C., it was found that the single fibers were firmly fused and excellent in thermal binder performance. When this short fiber was embedded in soil and biodegradability was evaluated, it was satisfactory.
実施例２
光学純度が９９．５％、ＭＦＲ（Ａ）が１８ｇ／１０分、ガラス転移温度Ｔｇが６３℃、結晶化温度Ｔｃが１３９℃、融点Ｔｍ１が１７５℃のポリＬ−乳酸樹脂を芯成分の重合体Ａとし、一方、光学純度が８６％、ＭＦＲ（Ｂ）が１５ｇ／１０分、ガラス転移温度Ｔｇが５６℃、結晶化温度Ｔｃと融点Ｔｍ１を示さないポリＬ−乳酸樹脂とこの樹脂に平均粒径１μｍのタルクを１０重量％添加したマスターチップとを混合比（重量比）＝１９／１の割合いで混合した組成物を鞘成分の重合体Ｂとし、紡糸温度を２２０℃、単孔吐出量を０．４８ｇ／分としたこと以外は実施例１と同様にして、未延伸糸トウを得た。次いで、第１ローラー温度を６０℃、第２ローラー温度を８５℃、全延伸倍率を２．１にしたこと以外は実施例１と同様にして、繊維長が５１ｍｍの短繊維を得た。得られた短繊維は、単繊維繊度が２．０ｄ、強度が３．７ｇ／ｄ、伸度が３８％、温度８０℃における乾熱収縮率が５％、捲縮数が１２個／２５ｍｍ、捲縮率が１３％で、繊維間の密着もないものであった。複屈折率△ｎを調査すると、芯成分が２９×１０-3、鞘成分が１５×１０-3、融点Ｔｍ２を調査すると、芯成分が１７５℃、鞘成分が１０８℃であった。この繊維を、温度１２０℃の熱風乾燥機を用い５分間熱処理したところ、単繊維間が強固に融着され、熱バインダー性能に優れることが分かった。この短繊維は、土中に埋設して生分解性を評価したところ、良好なものであった。
Example 2
Poly L-lactic acid resin having an optical purity of 99.5%, MFR (A) of 18 g / 10 min, a glass transition temperature Tg of 63 ° C., a crystallization temperature Tc of 139 ° C. and a melting point Tm1 of 175 ° C. On the other hand, poly-L-lactic acid resin having an optical purity of 86%, MFR (B) of 15 g / 10 min, glass transition temperature Tg of 56 ° C., crystallization temperature Tc and melting point Tm1, and an average of this resin A composition obtained by mixing a master chip to which 10% by weight of talc having a particle diameter of 1 μm with a mixing ratio (weight ratio) = 19/1 is a sheath component polymer B, and a spinning temperature is 220 ° C. and single hole discharge is performed. An undrawn yarn tow was obtained in the same manner as in Example 1 except that the amount was 0.48 g / min. Next, a short fiber having a fiber length of 51 mm was obtained in the same manner as in Example 1 except that the first roller temperature was 60 ° C., the second roller temperature was 85 ° C., and the total draw ratio was 2.1. The obtained short fiber has a single fiber fineness of 2.0d, a strength of 3.7 g / d, an elongation of 38%, a dry heat shrinkage at a temperature of 80 ° C. of 5%, a crimp number of 12/25 mm, The crimp rate was 13%, and there was no adhesion between the fibers. When the birefringence Δn was investigated, the core component was 29 × 10 −3 , the sheath component was 15 × 10 −3 , and the melting point Tm2 was examined. The core component was 175 ° C. and the sheath component was 108 ° C. When this fiber was heat-treated for 5 minutes using a hot air drier at a temperature of 120 ° C., it was found that the single fibers were firmly fused and excellent in thermal binder performance. When this short fiber was embedded in soil and biodegradability was evaluated, it was satisfactory.
実施例３
光学純度が８０％、ＭＦＲ（Ｂ）が１８ｇ／１０分、ガラス転移温度Ｔｇが５３℃、結晶化温度Ｔｃと融点Ｔｍ１を示さないポリＬ−乳酸樹脂とこの樹脂に平均粒径１μｍの酸化チタンを１０重量％添加したマスターチップとを混合比（重量比）＝１９／１の割合いで混合した組成物を鞘成分の重合体Ｂとしたこと以外は実施例２と同様にして、未延伸糸トウを得た。次いで、第１ローラー温度を６５℃、第２ローラー温度を８０℃としたこと以外は実施例２と同様にして、繊維長が５１ｍｍの短繊維を得た。得られた短繊維は、単繊維繊度が２．０ｄ、強度が３．４ｇ／ｄ、伸度が３７％、温度８０℃における乾熱収縮率が１２％、捲縮数が１２個／２５ｍｍ、捲縮率が１４％で、繊維間の密着もないものであった。複屈折率△ｎを調査すると、芯成分が２８×１０-3、鞘成分が５×１０-3、融点Ｔｍ２を調査すると、芯成分が１７５℃、鞘成分が１００℃であった。この繊維を、温度１１０℃の熱風乾燥機を用い５分間熱処理したところ、単繊維間が強固に融着され、熱バインダー性能に優れることが分かった。この短繊維は、土中に埋設して生分解性を評価したところ、良好なものであった。
Example 3
Poly L-lactic acid resin having an optical purity of 80%, MFR (B) of 18 g / 10 min, glass transition temperature Tg of 53 ° C., crystallization temperature Tc and melting point Tm1, and titanium oxide having an average particle diameter of 1 μm. Undrawn yarn in the same manner as in Example 2 except that the composition obtained by mixing 10% by weight of the master chip with the mixing ratio (weight ratio) = 19/1 was used as the sheath component polymer B. I got a tow. Next, a short fiber having a fiber length of 51 mm was obtained in the same manner as in Example 2 except that the first roller temperature was 65 ° C. and the second roller temperature was 80 ° C. The obtained short fiber has a single fiber fineness of 2.0 d, a strength of 3.4 g / d, an elongation of 37%, a dry heat shrinkage at a temperature of 80 ° C. of 12%, a crimp number of 12/25 mm, The crimp rate was 14% and there was no adhesion between the fibers. When the birefringence Δn was investigated, the core component was 28 × 10 −3 , the sheath component was 5 × 10 −3 , and the melting point Tm2 was examined. The core component was 175 ° C. and the sheath component was 100 ° C. When this fiber was heat-treated for 5 minutes using a hot air drier at a temperature of 110 ° C., it was found that the single fibers were firmly fused and excellent in thermal binder performance. When this short fiber was embedded in soil and biodegradability was evaluated, it was satisfactory.
実施例４
光学純度が９９％、ＭＦＲ（Ａ）が２５ｇ／１０分、ガラス転移温度Ｔｇが６０℃、結晶化温度Ｔｃが１３６℃、融点Ｔｍ１が１７０℃のポリＬ−乳酸樹脂を芯成分の重合体Ａとし、一方、光学純度が９４％、ＭＦＲ（Ｂ）が１８ｇ／１０分、ガラス転移温度Ｔｇが５９℃、結晶化温度Ｔｃと融点Ｔｍ１を示さないポリＬ−乳酸樹脂を鞘成分の重合体Ｂとし、紡糸温度を２１０℃、単孔吐出量を０．５ｇ／分としたこと以外は実施例２と同様にして、未延伸糸トウを得た。次いで、第１ローラー温度を６５℃、第２ローラー温度を９５℃、温浴バス温度を８０℃、全延伸倍率を２．３としたこと以外は実施例１と同様にして、繊維長が５１ｍｍの短繊維を得た。得られた短繊維は、単繊維繊度が２．０ｄ、強度が４．２ｇ／ｄ、伸度が３５％、温度８０℃における乾熱収縮率が２％、捲縮数が１３個／２５ｍｍ、捲縮率が１４％で、繊維間の密着もないものであった。複屈折率△ｎを調査すると、芯成分が３５×１０-3、鞘成分が２８×１０-3、融点Ｔｍ２を調査すると、芯成分が１７０℃、鞘成分が１３５℃であった。この繊維を、温度１４０℃の熱風乾燥機を用い５分間熱処理したところ、単繊維間が強固に融着され、熱バインダー性能に優れることが分かった。この短繊維は、土中に埋設して生分解性を評価したところ、良好なものであった。
Example 4
Polymer A having a core component of poly L-lactic acid resin having an optical purity of 99%, MFR (A) of 25 g / 10 min, glass transition temperature Tg of 60 ° C., crystallization temperature Tc of 136 ° C. and melting point Tm1 of 170 ° C. On the other hand, polymer sheath B made of poly L-lactic acid resin having optical purity of 94%, MFR (B) of 18 g / 10 min, glass transition temperature Tg of 59 ° C., and having no crystallization temperature Tc and melting point Tm1 An undrawn yarn tow was obtained in the same manner as in Example 2 except that the spinning temperature was 210 ° C. and the single hole discharge rate was 0.5 g / min. Next, the fiber length was 51 mm, as in Example 1, except that the first roller temperature was 65 ° C., the second roller temperature was 95 ° C., the bath temperature was 80 ° C., and the total draw ratio was 2.3. Short fibers were obtained. The obtained short fiber has a single fiber fineness of 2.0 d, a strength of 4.2 g / d, an elongation of 35%, a dry heat shrinkage rate of 2% at a temperature of 80 ° C., a crimp number of 13/25 mm, The crimp rate was 14% and there was no adhesion between the fibers. When the birefringence Δn was investigated, the core component was 35 × 10 −3 , the sheath component was 28 × 10 −3 , and the melting point Tm2 was examined. The core component was 170 ° C. and the sheath component was 135 ° C. When this fiber was heat-treated for 5 minutes using a hot air drier at a temperature of 140 ° C., it was found that the single fibers were firmly fused and excellent in thermal binder performance. When this short fiber was embedded in soil and biodegradability was evaluated, it was satisfactory.
実施例５
光学純度が９５％、ＭＦＲ（Ｂ）が１８ｇ／１０分、ガラス転移温度Ｔｇが５９℃、結晶化温度Ｔｃが１３２℃、融点Ｔｍ１が１４０℃のポリＬ−乳酸樹脂を鞘成分の重合体Ｂとしたこと以外は実施例４と同様にして、未延伸糸トウを得、以降、実施例４と同様にして、繊維長が５１ｍｍの短繊維を得た。得られた短繊維は、単繊維繊度が２．０ｄ、強度が４．０ｇ／ｄ、伸度が３５％、温度８０℃における乾熱収縮率が２％、捲縮数が１２個／２５ｍｍ、捲縮率が１５％で、繊維間の密着もないものであった。複屈折率△ｎを調査すると、芯成分が３８×１０-3、鞘成分が３０×１０-3、融点Ｔｍ２を調査すると、芯成分が１７０℃、鞘成分が１４０℃であった。この繊維を、温度１４７℃の熱風乾燥機を用い５分間熱処理したところ、単繊維がやや収縮して寸法安定性に若干劣るものの、単繊維間が強固に融着され、熱バインダー性能に優れることが分かった。この短繊維は、土中に埋設して生分解性を評価したところ、良好なものであった。
Example 5
Polymer B with poly-L-lactic acid resin having an optical purity of 95%, MFR (B) of 18 g / 10 min, glass transition temperature Tg of 59 ° C., crystallization temperature Tc of 132 ° C. and melting point Tm1 of 140 ° C. as a sheath component Except for the above, an undrawn yarn tow was obtained in the same manner as in Example 4, and thereafter, a short fiber having a fiber length of 51 mm was obtained in the same manner as in Example 4. The obtained short fiber has a single fiber fineness of 2.0 d, a strength of 4.0 g / d, an elongation of 35%, a dry heat shrinkage rate of 2% at a temperature of 80 ° C., a crimp number of 12/25 mm, The crimp rate was 15%, and there was no adhesion between the fibers. When the birefringence Δn was investigated, the core component was 38 × 10 −3 , the sheath component was 30 × 10 −3 , and the melting point Tm2 was examined. The core component was 170 ° C. and the sheath component was 140 ° C. When this fiber is heat-treated for 5 minutes using a hot air dryer at a temperature of 147 ° C., the single fibers are slightly shrunk and slightly inferior in dimensional stability, but the single fibers are firmly fused and have excellent thermal binder performance. I understood. When this short fiber was embedded in soil and biodegradability was evaluated, it was satisfactory.
参考例１
光学純度が９９％、ＭＦＲ（Ａ）が２５ｇ／１０分、ガラス転移温度Ｔｇが６０℃、結晶化温度Ｔｃが１３６℃、融点Ｔｍ１が１７０℃のポリＬ−乳酸樹脂を芯成分の重合体Ａとし、一方、光学純度が８０％、ＭＦＲ（Ｂ）が６０ｇ／１０分、ガラス転移温度Ｔｇが５３℃、結晶化温度Ｔｃと融点Ｔｍ１を示さないポリＬ−乳酸樹脂とこの樹脂に平均粒径１μｍの酸化チタンを１０重量％添加したマスターチップとを混合比（重量比）＝１９／１の割合いで混合した組成物を鞘成分の重合体Ｂとし、紡糸温度を２００℃として溶融紡出したこと以外は実施例３と同様にして、未延伸糸トウを得、以降、第３ローラー温度を７０℃としたこと以外は実施例３と同様にして、繊維長が５１ｍｍの短繊維を得た。得られた短繊維は、単繊維繊度が２．０ｄ、強度が３．２ｇ／ｄ、伸度が３５％、温度８０℃における乾熱収縮率が３８％、捲縮数が１２個／２５ｍｍ、捲縮率が１５％で、繊維間の密着が若干認められたものの、実用上問題のないものであった。複屈折率△ｎを調査すると、芯成分が２０×１０-3、鞘成分が８×１０-3、融点Ｔｍ２を調査すると、芯成分が１７０℃、鞘成分が１００℃であった。この繊維を、温度１１０℃の熱風乾燥機を用い５分間熱処理したところ、単繊維がやや収縮して寸法安定性に若干劣るものの、単繊維間が強固に融着され、熱バインダー性能に優れることが分かった。この短繊維は、土中に埋設して生分解性を評価したところ、良好なものであった。
Reference example 1
Polymer A having a core component of poly L-lactic acid resin having an optical purity of 99%, MFR (A) of 25 g / 10 min, glass transition temperature Tg of 60 ° C., crystallization temperature Tc of 136 ° C. and melting point Tm1 of 170 ° C. On the other hand, poly L-lactic acid resin having an optical purity of 80%, MFR (B) of 60 g / 10 min, glass transition temperature Tg of 53 ° C., crystallization temperature Tc and melting point Tm1, and an average particle diameter of this resin A composition obtained by mixing a master chip to which 10% by weight of 1 μm titanium oxide was added in a mixing ratio (weight ratio) = 19/1 was used as a sheath component polymer B, and melt spinning was performed at a spinning temperature of 200 ° C. Except that, an undrawn yarn tow was obtained in the same manner as in Example 3, and thereafter, a short fiber having a fiber length of 51 mm was obtained in the same manner as in Example 3 except that the third roller temperature was 70 ° C. . The obtained short fiber has a single fiber fineness of 2.0d, a strength of 3.2 g / d, an elongation of 35%, a dry heat shrinkage at a temperature of 80 ° C. of 38%, a number of crimps of 12/25 mm, Although the crimp rate was 15% and slight adhesion between fibers was observed, there was no practical problem. When the birefringence Δn was investigated, the core component was 20 × 10 −3 , the sheath component was 8 × 10 −3 , and the melting point Tm2 was examined. The core component was 170 ° C. and the sheath component was 100 ° C. When this fiber is heat-treated for 5 minutes using a hot air dryer at a temperature of 110 ° C., the single fibers are slightly shrunk and slightly inferior in dimensional stability, but the single fibers are firmly fused and have excellent thermal binder performance. I understood. When this short fiber was embedded in soil and biodegradability was evaluated, it was satisfactory.
参考例２
光学純度が９９％、ＭＦＲ（Ａ）が４ｇ／１０分、ガラス転移温度Ｔｇが６０℃、結晶化温度Ｔｃが１３６℃、融点Ｔｍ１が１７０℃のポリＬ−乳酸樹脂を芯成分の重合体Ａとし、一方、光学純度が９０％、ＭＦＲ（Ｂ）が４ｇ／１０分、ガラス転移温度Ｔｇが５８℃、結晶化温度Ｔｃと融点Ｔｍ１を示さないポリＬ−乳酸樹脂を鞘成分の重合体Ｂとし、紡糸温度を２５０℃として溶融紡出したこと以外は実施例１と同様にして、単繊維繊度が４．０ｄ、繊維長が５１ｍｍの短繊維を得た。溶融紡糸に際しては、紡糸温度が高いため紡糸口金近傍で発煙が多く、紡糸室の環境が悪化した。また、延伸に際しては、紡糸性の悪化に起因する糸切れが生じた。得られた短繊維は、複屈折率△ｎを調査すると、芯成分が２８×１０-3、鞘成分が１９×１０-3、融点Ｔｍ２を調査すると、芯成分が１６９℃、鞘成分が１２０℃であった。この繊維を、温度１３０℃の熱風乾燥機を用い５分間熱処理したところ、単繊維間が強固に融着され、熱バインダー性能に優れることが分かった。この短繊維は、土中に埋設して生分解性を評価したところ、良好なものであった。
Reference example 2
Polymer A having a core component of poly L-lactic acid resin having an optical purity of 99%, MFR (A) of 4 g / 10 min, glass transition temperature Tg of 60 ° C., crystallization temperature Tc of 136 ° C. and melting point Tm1 of 170 ° C. On the other hand, polymer sheath B is a poly-L-lactic acid resin having an optical purity of 90%, MFR (B) of 4 g / 10 min, a glass transition temperature Tg of 58 ° C., and a crystallization temperature Tc and no melting point Tm1. In the same manner as in Example 1 except that melt spinning was performed at a spinning temperature of 250 ° C., short fibers having a single fiber fineness of 4.0 d and a fiber length of 51 mm were obtained. During melt spinning, the spinning temperature was high, so there was a lot of smoke in the vicinity of the spinneret, and the environment of the spinning chamber deteriorated. Further, when drawing, yarn breakage due to deterioration of spinnability occurred. When the birefringence index Δn was investigated, the obtained short fiber was 28 × 10 −3 , sheath component 19 × 10 −3 , and melting point Tm2, and the core component was 169 ° C. and the sheath component was 120. ° C. When this fiber was heat-treated for 5 minutes using a hot air drier at a temperature of 130 ° C., it was found that the single fibers were firmly fused and excellent in thermal binder performance. When this short fiber was embedded in soil and biodegradability was evaluated, it was satisfactory.
比較例１
光学純度が７０％、ＭＦＲ（Ｂ）が１５ｇ／１０分、ガラス転移温度Ｔｇが４９℃、結晶化温度Ｔｃと融点Ｔｍ１を示さないポリＬ−乳酸樹脂を鞘成分の重合体Ｂとしたこと以外は実施例２と同様にして、未延伸糸トウを得た。次いで、実施例２と同様に延伸して短繊維化を試みたところ、延伸トウの単繊維間で密着が発生し、安定した捲縮加工が出来ず、また得られた短繊維間にも密着があり、カード機の通過性不良やネツプなどが生じた。このような現象が生じる理由は、両重合体間の光学純度差が大き過ぎるためであった。
Comparative Example 1
Other than using poly L-lactic acid resin having an optical purity of 70%, MFR (B) of 15 g / 10 min, glass transition temperature Tg of 49 ° C., crystallization temperature Tc and melting point Tm1 as polymer B of the sheath component Produced an undrawn yarn tow in the same manner as in Example 2. Next, when stretching was attempted in the same manner as in Example 2 to shorten the fiber, adhesion occurred between the single fibers of the drawn tow, stable crimping could not be performed, and adhesion between the obtained short fibers also occurred. There was a defect in the card machine's passability and nesting. The reason why such a phenomenon occurs is that the optical purity difference between the two polymers is too large.
比較例２
光学純度が９９％、ＭＦＲが２５ｇ／１０分、ガラス転移温度Ｔｇが６０℃、結晶化温度Ｔｃが１３６℃、融点Ｔｍ１が１７０℃のポリＬ−乳酸樹脂のみを用い、溶融紡糸を行った。すなわち、単軸のエクストルーダー型溶融押出し機を備えた紡糸装置を用い、直径０．４ｍｍ、孔数１８０個の紡糸孔を有する紡糸口金より紡糸温度２２０℃、単孔吐出量０．５９ｇ／分で溶融紡出し、空気冷却装置にて冷却、油剤付与をしながら紡糸速度１１００ｍ／分で巻取って未延伸糸を得た。得られた未延伸糸をリワインドして、２４万デニールの未延伸糸トウを形成した。次いで、全延伸倍率を２．６としたこと以外は実施例１と同様にして、繊維長が５１ｍｍの短繊維を得た。得られた短繊維は、単繊維繊度が２．１ｄ、強度が４．５ｇ／ｄ、伸度が３０％、温度１２０℃における乾熱収縮率が１１％、捲縮数が１２個／２５ｍｍ、捲縮率が１２％で、繊維間の密着もないものであった。複屈折率△ｎは３２×１０-3、融点Ｔｍ２は１７０℃であった。この短繊維は、土中に埋設して生分解性を評価したところ、良好なものであった。次に、この短繊維のみを原綿として用い、開繊機、パラレルカード機を通して目付が５０ｇ／ｍ2 のウエブを作成し、引き続き、このウエブを熱風循環型連続式乾燥機の中に通して処理温度１４５℃かつ処理時間６０秒間の条件で熱処理して不織布化を試みた。しかし、ウエブの面積収縮率が極めて高く、短繊維の接触部での熱融着がほとんど認められず、不織布としての形態保持性が悪いため、得られた不織布は実用性を有しないものであり、すなわち、この短繊維自体が熱バインダー繊維として問題を有することが分かった。
Comparative Example 2
Melt spinning was performed using only a poly-L-lactic acid resin having an optical purity of 99%, MFR of 25 g / 10 min, a glass transition temperature Tg of 60 ° C., a crystallization temperature Tc of 136 ° C., and a melting point Tm1 of 170 ° C. That is, using a spinning device equipped with a single-screw extruder type melt extruder, a spinning temperature of 220 ° C. and a single-hole discharge rate of 0.59 g / min from a spinneret having a spinning hole with a diameter of 0.4 mm and a hole number of 180 holes. And spinning with an air cooling device and winding at an spinning speed of 1100 m / min to obtain an undrawn yarn. The obtained undrawn yarn was rewound to form an undrawn yarn tow of 240,000 denier. Next, a short fiber having a fiber length of 51 mm was obtained in the same manner as in Example 1 except that the total draw ratio was 2.6. The obtained short fiber has a single fiber fineness of 2.1d, a strength of 4.5 g / d, an elongation of 30%, a dry heat shrinkage at a temperature of 120 ° C. of 11%, a crimp number of 12/25 mm, The crimp rate was 12%, and there was no adhesion between the fibers. The birefringence Δn was 32 × 10 −3 and the melting point Tm2 was 170 ° C. When this short fiber was embedded in soil and biodegradability was evaluated, it was satisfactory. Next, using only these short fibers as raw cotton, a web having a basis weight of 50 g / m 2 was prepared through a fiber opening machine and a parallel card machine, and this web was then passed through a hot air circulation type continuous dryer. An attempt was made to fabricate a nonwoven fabric by heat treatment at 145 ° C. and a treatment time of 60 seconds. However, the area shrinkage ratio of the web is extremely high, almost no heat fusion at the contact portion of short fibers is observed, and the shape retention as a nonwoven fabric is poor, so the obtained nonwoven fabric is not practical. That is, it has been found that this short fiber itself has a problem as a thermal binder fiber.
比較例３
光学純度が９６％、ＭＦＲ（Ｂ）が１８ｇ／１０分、ガラス転移温度Ｔｇが６０℃、結晶化温度Ｔｃが１３３℃、融点Ｔｍ１が１４６℃のポリＬ−乳酸樹脂を鞘成分の重合体Ｂとし、紡糸温度を２２０℃として溶融紡出したこと以外は実施例４と同様にして、未延伸糸トウを得、以降も実施例４と同様にして、繊維長が５１ｍｍの短繊維を得た。得られた短繊維は、単繊維繊度が２．０ｄ、強度が４．１ｇ／ｄ、伸度が３４％、温度８０℃における乾熱収縮率が２％、捲縮数が１３個／２５ｍｍ、捲縮率が１４％で、繊維間の密着もないものであった。複屈折率△ｎを調査すると、芯成分が３８×１０-3、鞘成分が３２×１０-3、融点Ｔｍ２を調査すると、芯成分が１７０℃、鞘成分が１４７℃であった。この繊維を、温度１５５℃の熱風乾燥機を用い５分間熱処理したところ、単繊維が大きく収縮し、寸法安定性に劣り、実用性の乏しいものであった。
Comparative Example 3
Polymer B with poly-L-lactic acid resin having an optical purity of 96%, MFR (B) of 18 g / 10 min, glass transition temperature Tg of 60 ° C., crystallization temperature Tc of 133 ° C. and melting point Tm1 of 146 ° C. as sheath component The undrawn yarn tow was obtained in the same manner as in Example 4 except that the melt spinning was performed at a spinning temperature of 220 ° C., and the short fiber having a fiber length of 51 mm was obtained in the same manner as in Example 4 thereafter. . The obtained short fiber has a single fiber fineness of 2.0 d, a strength of 4.1 g / d, an elongation of 34%, a dry heat shrinkage rate of 2% at a temperature of 80 ° C., a crimp number of 13/25 mm, The crimp rate was 14% and there was no adhesion between the fibers. When the birefringence Δn was investigated, the core component was 38 × 10 −3 , the sheath component was 32 × 10 −3 , and the melting point Tm2 was examined. The core component was 170 ° C. and the sheath component was 147 ° C. When this fiber was heat-treated for 5 minutes using a hot air dryer at a temperature of 155 ° C., the single fiber was greatly shrunk, the dimensional stability was poor, and the practicality was poor.
実施例８
実施例１で得た短繊維のみを原綿として用い、開繊機、パラレルカード機を通して目付が５０ｇ／ｍ2 のウエブを作成し、引き続き、このウエブを熱風循環型連続式乾燥機の中に通して処理温度１２５℃かつ処理時間６０秒間の条件で熱処理して、不織布を得た。得られた不織布の性能を表１に示す。この不織布は、表１から明らかなように、嵩高であり、強力、耐久性に優れ、しかも生分解性をも有する熱接着型不織布であった。
Example 8
Using only the short fibers obtained in Example 1 as raw cotton, a web having a basis weight of 50 g / m 2 was prepared through a fiber opening machine and a parallel card machine, and this web was then passed through a hot air circulation type continuous dryer. A non-woven fabric was obtained by heat treatment under conditions of a treatment temperature of 125 ° C. and a treatment time of 60 seconds. Table 1 shows the performance of the obtained nonwoven fabric. As apparent from Table 1, this nonwoven fabric was a heat-bonding nonwoven fabric that was bulky, excellent in strength and durability, and also biodegradable.
実施例９
実施例２で得た短繊維のみを原綿として用い、開繊機、パラレルカード機を通して目付が５０ｇ／ｍ2 のウエブを作成し、引き続き、このウエブを熱風循環型連続式乾燥機の中に通して処理温度１１５℃かつ処理時間６０秒間の条件で熱処理して、不織布を得た。得られた不織布の性能を表１に示す。この不織布は、表１から明らかなように、嵩高であり、強力、耐久性に優れ、しかも生分解性をも有する熱接着型不織布であった。
Example 9
Using only the short fiber obtained in Example 2 as raw cotton, a web having a basis weight of 50 g / m 2 was prepared through a fiber opening machine and a parallel card machine, and this web was then passed through a hot air circulation type continuous dryer. A nonwoven fabric was obtained by heat treatment under conditions of a treatment temperature of 115 ° C. and a treatment time of 60 seconds. Table 1 shows the performance of the obtained nonwoven fabric. As apparent from Table 1, this nonwoven fabric was a heat-bonding nonwoven fabric that was bulky, excellent in strength and durability, and also biodegradable.
実施例１０
実施例３で得た短繊維のみを原綿として用い、開繊機、パラレルカード機を通して目付が５０ｇ／ｍ2 のウエブを作成し、引き続き、このウエブを熱風循環型連続式乾燥機の中に通して処理温度１１０℃かつ処理時間６０秒間の条件で熱処理して、不織布を得た。得られた不織布の性能を表１に示す。この不織布は、表１から明らかなように、嵩高であり、強力、耐久性に優れ、しかも生分解性をも有する熱接着型不織布であった。
Example 10
Using only the short fibers obtained in Example 3 as raw cotton, a web having a basis weight of 50 g / m 2 was prepared through a fiber opening machine and a parallel card machine, and then this web was passed through a hot air circulation type continuous dryer. A non-woven fabric was obtained by heat treatment under conditions of a treatment temperature of 110 ° C. and a treatment time of 60 seconds. Table 1 shows the performance of the obtained nonwoven fabric. As apparent from Table 1, this nonwoven fabric was a heat-bonding nonwoven fabric that was bulky, excellent in strength and durability, and also biodegradable.
実施例１１
実施例４で得た短繊維のみを原綿として用い、開繊機、パラレルカード機を通して目付が５０ｇ／ｍ2 のウエブを作成し、引き続き、このウエブを熱風循環型連続式乾燥機の中に通して処理温度１４０℃かつ処理時間６０秒間の条件で熱処理して、不織布を得た。得られた不織布の性能を表１に示す。この不織布は、表１から明らかなように、嵩高であり、強力、耐久性に優れ、しかも生分解性をも有する熱接着型不織布であった。
Example 11
Using only the short fibers obtained in Example 4 as raw cotton, a web having a basis weight of 50 g / m 2 was prepared through a fiber opening machine and a parallel card machine, and this web was subsequently passed through a hot air circulation type continuous dryer. A non-woven fabric was obtained by heat treatment under conditions of a treatment temperature of 140 ° C. and a treatment time of 60 seconds. Table 1 shows the performance of the obtained nonwoven fabric. As apparent from Table 1, this nonwoven fabric was a heat-bonding nonwoven fabric that was bulky, excellent in strength and durability, and also biodegradable.
実施例１２
実施例２で得た短繊維と比較例２で得た短繊維とを混合比（重量比）＝５０／５０で混合した後、開繊機、パラレルカード機を通して目付が５０ｇ／ｍ2 のウエブを作成し、引き続き、このウエブを熱風循環型連続式乾燥機の中に通して処理温度１１５℃かつ処理時間６０秒間の条件で熱処理して、不織布を得た。得られた不織布の性能を表１に示す。この不織布は、表１から明らかなように、嵩高であり、強力、耐久性に優れ、しかも生分解性をも有する熱接着型不織布であった。
Example 12
After mixing the short fiber obtained in Example 2 and the short fiber obtained in Comparative Example 2 at a mixing ratio (weight ratio) = 50/50, a web having a basis weight of 50 g / m 2 was passed through a fiber opening machine and a parallel card machine. Subsequently, the web was passed through a hot air circulation type continuous dryer and heat-treated at a treatment temperature of 115 ° C. and a treatment time of 60 seconds to obtain a nonwoven fabric. Table 1 shows the performance of the obtained nonwoven fabric. As apparent from Table 1, this nonwoven fabric was a heat-bonding nonwoven fabric that was bulky, excellent in strength and durability, and also biodegradable.
実施例１３
実施例２で得た短繊維と比較例２で得た短繊維とを混合比（重量比）＝１０／９０で混合した後、開繊機、パラレルカード機を通して目付が５０ｇ／ｍ2 のウエブを作成し、引き続き、実施例１２と同様にして、不織布を得た。得られた不織布の性能を表１に示す。この不織布は、他のポリ乳酸系繊維との混合比が低いため強力水準が低目であるものの、表１から明らかなように、実用的な強力を有し、嵩高であり、耐久性に優れ、しかも生分解性をも有する熱接着型不織布であった。
Example 13
After mixing the short fiber obtained in Example 2 and the short fiber obtained in Comparative Example 2 at a mixing ratio (weight ratio) = 10/90, a web having a basis weight of 50 g / m 2 was passed through a fiber opening machine and a parallel card machine. Then, a nonwoven fabric was obtained in the same manner as in Example 12. Table 1 shows the performance of the obtained nonwoven fabric. Although this nonwoven fabric has a low level of strength due to its low mixing ratio with other polylactic acid fibers, as is apparent from Table 1, it has practical strength, is bulky, and has excellent durability. Moreover, it was a heat-bonding nonwoven fabric having biodegradability.
実施例１４
実施例２で得た短繊維と、単繊維繊度が２ｄ、繊維長が５１ｍｍのレーヨン短繊維とを混合比（重量比）＝５０／５０で混合した後、開繊機、パラレルカード機を通して目付が５０ｇ／ｍ2 のウエブを作成し、引き続き、このウエブを熱風循環型連続式乾燥機の中に通して処理温度１１５℃かつ処理時間６０秒間の条件で熱処理して、不織布を得た。得られた不織布の性能を表１に示す。この不織布は、他のレーヨン短繊維と混合しても、表１から明らかなように、強力、耐久性に優れ、しかも生分解性をも有する熱接着型不織布であった。
Example 14
After mixing the short fiber obtained in Example 2 and the short fiber with a single fiber fineness of 2d and a fiber length of 51 mm at a mixing ratio (weight ratio) = 50/50, the basis weight is obtained through a fiber opening machine and a parallel card machine. A web of 50 g / m 2 was prepared, and then this web was passed through a hot air circulation type continuous dryer and heat-treated at a treatment temperature of 115 ° C. and a treatment time of 60 seconds to obtain a nonwoven fabric. Table 1 shows the performance of the obtained nonwoven fabric. Even if this nonwoven fabric was mixed with other rayon short fibers, as is apparent from Table 1, it was a heat-bonding nonwoven fabric that was excellent in strength and durability and also had biodegradability.
実施例１５
実施例２で得た短繊維とコツトン繊維とを混合比（重量比）＝５０／５０で混合した後、開繊機、パラレルカード機を通して目付が５０ｇ／ｍ2 のウエブを作成し、引き続き、実施例１４と同様にして、不織布を得た。得られた不織布の性能を表１に示す。この不織布は、他のコツトン繊維と混合しても、表１から明らかなように、強力、耐久性に優れ、しかも生分解性をも有する熱接着型不織布であった。
Example 15
After mixing the short fiber and the cotton fiber obtained in Example 2 at a mixing ratio (weight ratio) = 50/50, a web having a basis weight of 50 g / m 2 was prepared through a fiber opening machine and a parallel card machine, and subsequently carried out. In the same manner as in Example 14, a nonwoven fabric was obtained. Table 1 shows the performance of the obtained nonwoven fabric. Even when this nonwoven fabric was mixed with other cotton fibers, as is apparent from Table 1, it was a heat-bonding nonwoven fabric that was excellent in strength and durability and also had biodegradability.
比較例４
比較例２で得た短繊維と、単繊維繊度が２ｄ、繊維長が５１ｍｍのレーヨン短繊維とを混合比（重量比）＝５０／５０で混合した後、開繊機、パラレルカード機を通して目付が５０ｇ／ｍ2 のウエブを作成し、引き続き、このウエブを熱風循環型連続式乾燥機の中に通して処理温度１８０℃かつ処理時間６０秒間の条件で熱処理して、不織布を得た。得られた不織布の性能を表１に示す。この不織布は、ウエブの面積収縮率が低く寸法安定性に優れるものの、表１から明らかなように、強力、嵩高性、耐久性のいずれにおいても、劣るものであった。
Comparative Example 4
After mixing the short fiber obtained in Comparative Example 2 with the rayon short fiber having a single fiber fineness of 2d and a fiber length of 51 mm at a mixing ratio (weight ratio) = 50/50, the basis weight is obtained through a fiber opening machine and a parallel card machine. A web of 50 g / m 2 was prepared, and then this web was passed through a hot-air circulation type continuous dryer and heat-treated at a treatment temperature of 180 ° C. and a treatment time of 60 seconds to obtain a nonwoven fabric. Table 1 shows the performance of the obtained nonwoven fabric. Although this nonwoven fabric has a low area shrinkage ratio of the web and excellent dimensional stability, it is inferior in all of strength, bulkiness and durability, as is apparent from Table 1.
比較例５
実施例２で得た短繊維と比較例２で得た短繊維とを混合比（重量比）＝８／９２で混合した後、開繊機、パラレルカード機を通して目付が５０ｇ／ｍ2 のウエブを作成し、引き続き、このウエブを熱風循環型連続式乾燥機の中に通して処理温度１１５℃かつ処理時間６０秒間の条件で熱処理して、不織布を得た。得られた不織布の性能を表１に示す。この不織布は、表１から明らかなように、実施例２で得た短繊維の混合比が低いために単繊維間の融着が弱く、強力、嵩高性、耐久性のいずれにおいても、劣るものであった。
Comparative Example 5
After mixing the short fiber obtained in Example 2 and the short fiber obtained in Comparative Example 2 at a mixing ratio (weight ratio) = 8/92, a web having a basis weight of 50 g / m 2 was passed through a fiber opening machine and a parallel card machine. Subsequently, the web was passed through a hot air circulation type continuous dryer and heat-treated at a treatment temperature of 115 ° C. and a treatment time of 60 seconds to obtain a nonwoven fabric. Table 1 shows the performance of the obtained nonwoven fabric. As is apparent from Table 1, this nonwoven fabric has a low mixing ratio of the short fibers obtained in Example 2 and thus weak fusion between single fibers, and is inferior in any of strength, bulkiness and durability. Met.
比較例６
比較例３で得た短繊維のみを原綿として用い、開繊機、パラレルカード機を通して目付が５０ｇ／ｍ2 のウエブを作成し、引き続き、このウエブを熱風循環型連続式乾燥機の中に通して処理温度１５０℃かつ処理時間６０秒間の条件で熱処理して、不織布を得た。得られた不織布の性能を表１に示す。この不織布は、表１から明らかなように、強力、嵩高性、耐久性のいずれにおいても、劣るものであった。
Comparative Example 6
Using only the short fibers obtained in Comparative Example 3 as raw cotton, a web having a basis weight of 50 g / m 2 was prepared through a fiber opening machine and a parallel card machine, and this web was subsequently passed through a hot air circulation type continuous dryer. A non-woven fabric was obtained by heat treatment under conditions of a treatment temperature of 150 ° C. and a treatment time of 60 seconds. Table 1 shows the performance of the obtained nonwoven fabric. As apparent from Table 1, this nonwoven fabric was inferior in all of strength, bulkiness and durability.
Ａ 光学純度が高い重合体
Ｂ 重合体Ａよりも光学純度が低い重合体
A Polymer with high optical purity B Polymer with lower optical purity than polymer A
Claims (4)
５≦ＭＦＲ（Ａ）≦１００ ・・・・・（１）
５≦ＭＦＲ（Ｂ）≦８０ ・・・・・（２）
ＭＦＲ（Ａ）≧ＭＦＲ（Ｂ） ・・・・・（３）
ＭＦＲ（Ａ）：光学純度が高い重合体Ａのメルトフローレート（ｇ／１０分）
ＭＦＲ（Ｂ）：重合体Ａよりも光学純度が低い重合体Ｂのメルトフローレート（ｇ／１０分） It consists of two types of polylactic acid polymers A and B having optical purity of 5 to 20% different from each other. The melt flow rate value MFR (A) of the polymer A and the melt flow rate value MFR (B of the polymer B) ) Satisfying the following formulas ( 1 ) to ( 3 ), and the polymer B having low optical purity is composited so as to be exposed on a part of the fiber surface. .
5 ≦ MFR (A) ≦ 100 ( 1 )
5 ≦ MFR (B) ≦ 80 ( 2 )
MFR (A) ≧ MFR (B) ( 3 )
MFR (A): Melt flow rate of polymer A having high optical purity (g / 10 min)
MFR (B): Melt flow rate of polymer B having a lower optical purity than polymer A (g / 10 min)
５≦ＭＦＲ（Ａ）≦１００ ・・・・・（１）
５≦ＭＦＲ（Ｂ）≦８０ ・・・・・（２）
ＭＦＲ（Ａ）≧ＭＦＲ（Ｂ） ・・・・・（３）
ＭＦＲ（Ａ）：光学純度が高い重合体Ａのメルトフローレート（ｇ／１０分）ＭＦＲ（Ｂ）：重合体Ａよりも光学純度が低い重合体Ｂのメルトフローレート（ｇ／１０分） Two types of polylactic acid-based polymers A and B having optical purity different from each other by 5 to 20%, the melt flow rate value MFR (A) of the polymer A and the melt flow rate value MFR of the polymer B ( B) and a polymer satisfying the following formulas ( 1 ) to ( 3 ) are hot-stretched after melt-combined spinning so that the polymer B of low optical purity is exposed on a part of the fiber surface. A method for producing a polylactic acid-based composite short fiber.
5 ≦ MFR (A) ≦ 100 ( 1 )
5 ≦ MFR (B) ≦ 80 ( 2 )
MFR (A) ≧ MFR (B) ( 3 )
MFR (A): Melt flow rate of polymer A with high optical purity (g / 10 min) MFR (B): Melt flow rate of polymer B with lower optical purity than polymer A (g / 10 min)
The method for producing a polylactic acid-based composite short fiber according to claim 3 , wherein at least a crystal nucleating agent is added to the polymer B.
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| JP2008335595A JP2009114619A (en) | 2008-12-28 | 2008-12-28 | Polylactic acid conjugated staple fiber and method for production thereof |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108468102A (en) * | 2018-03-27 | 2018-08-31 | 上海创菲新材料技术有限公司 | Degradable water-absorbing core and its preparation method and application |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH07310236A (en) * | 1994-05-18 | 1995-11-28 | Kanebo Ltd | Thermofusible polylactic acid fiber |
| JPH0995847A (en) * | 1995-10-03 | 1997-04-08 | Unitika Ltd | Nonwoven fabric of polylactate-based filament and its production |
| JPH101855A (en) * | 1996-04-15 | 1998-01-06 | Unitika Ltd | Biodegradable short fiber nonwoven fabric and its production |
-
2008
- 2008-12-28 JP JP2008335595A patent/JP2009114619A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH07310236A (en) * | 1994-05-18 | 1995-11-28 | Kanebo Ltd | Thermofusible polylactic acid fiber |
| JPH0995847A (en) * | 1995-10-03 | 1997-04-08 | Unitika Ltd | Nonwoven fabric of polylactate-based filament and its production |
| JPH101855A (en) * | 1996-04-15 | 1998-01-06 | Unitika Ltd | Biodegradable short fiber nonwoven fabric and its production |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108468102A (en) * | 2018-03-27 | 2018-08-31 | 上海创菲新材料技术有限公司 | Degradable water-absorbing core and its preparation method and application |
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