JP3992385B2 - High elongation polyester filament yarn - Google Patents

Description

【００１３】
ここでＥＩ_b（％）は、本発明のポリエステルフィラメント糸の残留伸度、ＥＬ₀（％）は該伸度向上剤を含まない以外は本発明と同一の紡糸条件下で得られたポリエステルフィラメント糸の残留伸度である。
【００１４】
【発明の実施の形態】
紡出されつつある個々のフィラメント中でポリマーの分子配向に対して“コロ”として機能する粒子状の繊維伸度向上剤をポリエステル重量を基準として０．２〜１０重量％分散せしめたポリエステルを溶融紡糸し、１５００ｍ／ｍｉｎ〜８０００ｍ／ｍｉｎの引取速度で得た、残留伸度増加率（Ｉ）が８％以上であるフィラメント紡出糸（以下、単に紡出糸と称する）を得る、という概念自体、前掲のＥＰ４７４６４Ａ、明細書に開示されている。
【００１５】
これに対して、本発明は上記ＥＰ明細書では言及されていないところの、繊維伸度向上剤の熱変形温度（Ｔ）を特定することにより、該ＥＰ明細書では未解決のまま放置されていた引取速度2500m/分未満の低引取速度領域における生産性の向上、すなわち従来対比伸度向上効果の大きい伸度向上剤を添加することで生産性および紡糸調子を向上させるという課題を克服したものである。
【００１６】
まず、本発明の要件の意義について述べる。
本発明において、引取速度が2500m/分未満の紡出糸に作用するに繊維伸度向上剤の熱変形温度（Ｔ）は、105〜160℃の範囲であることが必要である。該温度（Ｔ）が105℃未満では、該剤の伸長変形抵抗体としての機能が不十分である。一方該温度（Ｔ）が160℃を越えると、紡糸ライン上で過剰な伸張粘度の差が生て、紡出糸が追従できないほどの急激な細化が発生する。
【００１７】
次に、繊維伸度向上剤については、ポリメチルメタクリレート系重合体が挙げられる。
【００１８】
これらの繊維伸度向上剤の具体的な作用は、ポリエステルと実質的に非相溶な海／島状態、つまり、ポリエステルを海成分、粒子状の繊維伸度向上剤を島成分として口金孔から吐出された後、紡糸ライン上で冷却細化過程を経る際に、ポリエステルよりも先に溶融状態からガラス状態へと転移し、紡糸応力（張力）に対して伸長変形低抗体の役割を果たす。つまり、口金近傍のポリマー温度が高い状態でのブレンド系の伸長粘度に関して、従来の伸長粘度式に従わない非線形性増加をもたらし、その結果細化を促進し、紡出糸の糸速度をより吐出孔に近い位置で最終引取速度に到達せしめる。
【００１９】
そのため、熱変形温度（Ｔ）が、105℃未満の繊維伸度向上剤では、ガラス状態への転移がポリエステルのそれに近い、換言すれば、紡糸ライン上でのガラス状態への転移が遅いため、紡糸応力（張力）に対する伸長変形低抗体としての役割が十分に発揮されない。勿論、前記ＥＰ明細書に記載された熱変形温度（Ｔ）が98℃のような低温のものでは、ポリエステルの熱変形温度(70℃）との差が28℃とさらに小さいため、2500m/分未満の低引取速度領域では、伸長変形抵抗体としての機能は十分に発揮されず、50%以上の高い伸度向上効果を発現させるには紡糸性に影響するほどの添加量が必要とされる。
【００２０】
これら重合体の分子量は、伸長変形抵抗体としてポリエステルとは独立に、高分子量体として構造粘弾性の発現を必要とすることから少なくとも２０００以上の分子量（重量平均）を有していることが好ましく、特に２０００以上3０万以下が好ましい。分子量が２０００よりも小さいと、高分子量体としての構造粘弾性を発現し難く、応力担持体として作用し難い。一方、３０万を超えると、重合体の凝集エネルギーが極めて高く、ポリエステルへの分散が極めて困難になる。特に好ましい分子量の範囲は1万以上２５万以下であり、このような高分子量重合体の場合、耐熱性も向上する。
【００２１】
このような繊維伸度向上剤の具体例としては、分子量が1万以上３０万以下であって、ＡＳＴＭ−Ｄ１２３８で規定される条件（２３０℃、荷重３．８ｋｇｆ）において、メルトインデックス（Ｍ．Ｉ．）が０．５〜１５．０ｇ／ｍｉｎであるポリメチルメタクリレート系共重合体ないしその誘導体である。これらの特定の物性を有する重合体は、ポリエステルの紡糸温度において、優れた熱安定性と伸度向上効果を呈する。
【００２２】
本発明においてポリエステルとは、芳香族ジカルボン酸を主たる酸成分とする繊維形成能を有するポリエステルを指称し、例えば、ポリエチレンテレフタレート、ポリトリメチレンテレフタレート、ポリテトラメチレンテレフタレート、ポリシクロヘキサンジメチレンテレフタレート、ポリエチレン―２，６―ナフタレンジカルボキシレート等を挙げることができる。また、これらポリエステルは第３成分として、ブタンジオールのようなアルコール成分又はイソフタル酸等のジカルボン酸を共重合させた共重合体でも良く、更にこれら各種ポリエステルの混合体でも良い。これらのうちポリエチレンテレフタレート系重合体が最適である。
【００２３】
これらポリエステルには、必要に応じて艶消し剤、熱安定剤、紫外線吸収剤、帯電防止剤、末端停止剤、蛍光増白剤等が含まれていても良い。また、これらのポリエステルは紡糸性および糸物性の観点から固有粘度が０．４〜１．１であることが望ましい。
【００２４】
ところで、本発明の紡出糸の残留伸度向上率（Ｉ）が50％以上であることは、該紡出糸の複屈折率とも相関がある。この点から、本発明の紡出糸の複屈折率(△ｎ）は、0.030以下の範囲にあることが好ましい。本発明の効果が発現される2500m/分未満の引取速度において、△ｎが0.030を越える場合、（Ｉ）は70%未満である。また、本発明の伸度向上剤は、その熱変形温度（Ｔ）がポリエステルのそれよりも、少なくとも30℃を越える範囲にあるため、経時による物性の変化が起こりにくく、多様な糸加工、後加工性に優れた性能を示す。
【００２５】
ポリエステルへの繊維伸度向上剤の添加に当たっては、任意の方法を採用することができる。例えばポリエステルの重合末期段階で該剤を混合してもよく、また、ポリエステルと前記剤とを溶融混合して、押出し冷却後、切断してチップ化してもよい。更には、サイドストリームから該剤を溶融状態でポリエステルの溶融紡糸装置に、動的および／または静的ミクスチャーを介して導入してもよい。また、両者をチップ状で混合した後、そのまま溶融紡糸してもよい。その中でも、連重直紡ラインのポリエステル配管から一部のポリマーを引き出し、それをマトリックスとして該剤を混練り分散させたものを元のニートポリマーラインへ、任意の動的および／または静的ミクスチャーを介して戻し、各配管に分配するという手法が最も好ましい。
【００２６】
上述のように繊維伸度向上剤が添加された溶融ポリマーは、紡糸パック内に設置された４０μ以下のポアサイズをもつフィルターを通して、粗大粒子の吐出ポリマー流中への混入を抑制し、更に１５０〜１５００の範囲のみかけの紡糸ドラフト（率）のもとに、紡出するのが好ましい。この紡糸ドラフトについては、１５０未満だと吐出孔を通過するポリマー流は高い剪断力を受け、粒子状の繊維伸度向上剤はフィラメントの長手方向に引きちぎられ、粗大粒子の混入は抑制されるが、伸長変形抵抗体としての機能が若干低下し、１５００を越えると、吐出孔内での剪断力による引きちぎり効果が小さくなり、伸長変形抵抗体としての機能は向上するが、粗大粒子が発生しやすい。
【００２７】
さらに、その他の好ましい紡糸要件としては紡糸温度（口金温度）および紡糸口金下の冷却である。
【００２８】
前者については、繊維伸度向上剤が分散した溶融ポリエステルを吐出する際の口金温度を通常よりも低くすることで、口金吐出後の伸度向上剤の伸長粘度がより紡糸ライン上流で大きくなるので好ましく、特に口金温度２７０〜２９０℃が好ましい。２７０未満では、ポリエステルの種類にもよるが、曵糸性が低下しはじめ、他方２９０℃を越えると、伸度向上剤である附加重合体の耐熱安定性が低下しはじめる。
【００２９】
後者の口金下の冷却は、横吹き冷却の場合、その風速を０．１５〜０．６ｍ／ｓｅｃの範囲に維持することが好ましい。風速が０．１５ｍ／ｓｅｃ未満では、フィラメントの長手方向の斑がでやすい。また、０．６０ｍ／ｓｅｃを超えると、ポリエステル側の伸長粘度が上昇するので、残留伸度の増加幅が小さくなる。
【００３０】
以上のような、紡糸条件で引き取れた紡出糸は、油剤を付与された後、ゴデットローラーなどを介して巻き取っても良いし、該ローラーなどを介さずに巻き取っても良い。ここで本発明のいう引取速度とはゴデーットローラを介した場合は第1ゴデーットローラーの速度であり、該ローラーを介さなかった場合は捲取速度である。 また、このようにして巻き取られる紡出糸は、紡糸工程の任意の箇所で空気交絡されても良い。
【００３１】
以上に述べた紡糸の態様は、本発明の紡出糸を単独で得る場合のみならず、種々の形で応用される。例えば、繊維伸度向上剤を混合したポリエステルと該剤を実質的に含まないポリエステルとを同一口金から吐出することによって、あたかも紡糸速度の異なる（互いに伸度の異なる）未延伸糸を複合した特性を示す混繊糸を直接捲き取ることも可能である。
【００３２】
【実施例】
本発明で採用する物性値の測定方法について説明する。
（１）熱変形温度（Ｔ）
ＡＳＴＭ Ｄ−６４８に従う。
（２）紡出糸の複屈折率（Δｎ）
１―ブロモナフタレンを浸透液として用いて、偏光顕微鏡にて波長５３０ｎｍの単色光を用いて、緩衝縞を測定し、下記式Δｎを算出する。
Δｎ＝５３０（ｎ＋θ／１８０）／Ｘ
ｎ：縞数、θ：コンペンセーター回転角度、Ｘ：繊維直径
（３）残留伸度
紡出糸を気温２５℃×湿度６０％の高温恒湿に保たれた部屋に１昼夜放置した後、サンプル長さ１００ｍｍを島津製作所製張試験機テンシロンにセットし、２００ｍｍ／ｍｉｎの速度、即ちひづみ速度２ｍｉｎ−１にて引張り破断伸度を測定する。
（４）メルトインデックス
ＡＳＴＭ Ｄ−１２３８に従う。
以下、実施例により本発明を説明する。
【００３３】
［実施例１］
固有粘度０．６４、艶消剤として酸化チタンをポリエステル重量を基準として０．３ｗｔ％を含むポリエチレンテレフタレートチップを１６０℃で５時間乾燥した後、直径２５mmの１軸フルフライト型溶融押出し機にて３００℃で溶融した。次いで、熱変形温度（Ｔ）が９８、１０５または１２１℃のＰＭＭＡ、または熱変形温度（Ｔ）が１３７、１４５、１６０または１６８℃となるようメタクリル酸メチル、アクリル酸イミド付加物およびスチレンの３成分の組成をそれぞれ変更して共重合したＰＭＭＡ系重合体をサイドストリームから溶融状態で、押出し機中の該溶融ポリエステルへ導入し、次いで１２段のスタティックミキサーを通して混合分散させた。そして該混合分散状態のポリマーを、口金直上に設けた400μｍのポアサイズをもつ金属繊維フィルターに通した後、直径０．４ｍｍφ―ランド長０．８ｍｍ（Ｌ）の吐出孔を３６個有する紡糸口金から、口金部の温度２８５℃で該溶融ポリマーを表１のＮｏ．１〜１３に示すような各引取速度にあわせてその吐出量を変化させつつ吐出した。さらに口金下下方９ｃｍ〜１００ｃｍに設けた横吹きの紡糸冷却筒から２５℃の空気を０．２３ｍ／ｓｅｃの速度で吹きつけて吐出ポリマー流を冷却固化せしめ、ＯＰＵ０．２５〜０．３０ｗｔ％範囲内で油剤付着処理を施した後、１５０デニール／３６フィラメント数の紡出糸を未延伸状態で巻取った。結果を表１に示す。
【００３４】
【表１】

【００３５】
以下、表１について考察する。
【００３６】
No.１〜4、1２および1３において、Ｔｇによる影響を比較すれば、Ｔｇの上昇に伴い、伸度向上効果が向上し、ＰＭＭＡのＴｇが低いNo.1以外は、残留伸度向上率５０％以上という高い伸度向上効果と安定な紡糸調子とを達成した。一方No.７はＰＭＭＡのＴｇは本発明の要件を満たすものの添加量が少ないために、十分な伸度向上効果を達成されず、△ｎも、０．０３０を越えている。またNo.１１は添加量が多いために、単糸切れが発生し、No.１３はＴｇが168℃のPMMA系重合体を添加したため、伸度向上効果は大きいものの曳糸性が悪化した。
【００３７】
［実施例２］
直径０．３ｍｍφ―ランド長０．６ｍｍ（Ｌ）の吐出孔を３６個有する紡糸口金を用い、メチルメタクリル酸メチル、アクリル酸イミドおよびスチレンの３成分を共重合したPMMA系重合体（熱変形温度（Ｔ）：137℃、メルトインデックス230℃、荷重３．８ｋｇが０．８ｇ／10分）を繊維伸度向上剤として４重量％添加した以外は、実施例１と同様の方法を用い、表２に示すＮｏ．１４〜１６の各デニールになるよう吐出量を調整しつつ、引取速度1500m/分で捲きとった。結果を表2に示す。
【００３８】
【表２】

【００３９】
以下、表２について考察する。
デニール依存性について検討したNo．１４〜１６において、口金から吐出されたポリマー流の冷却が進行し易い細デニールのものほど、伸度向上効果が大きかった。これは、冷却によりＰＭＭＡ系重合体の伸長変形抵抗体としての作用が強化されたものと推定される。
【００４０】
この現象は、従来のポリエステルに非相溶性の附加重合体を含まないポリエステルのデニール依存性とは、全く異なるものである。
【００４１】
【発明の効果】
熱変形温度（Ｔ）が105〜160℃の範囲にある粒子状の繊維伸度向上剤をポリエステル重量を基準として0.5〜6.0重量％添加分散することで、従来の繊維伸度向上剤では十分な機能が発揮されなかった引取速度2500m/分未満の引取速度領域においても、高い伸度向上効果が図られる。そのため、従来対比より少ない添加量で高伸度化された生産性および紡糸調子の向上したポリエステルフィラメント糸が提供される。[0001]
BACKGROUND OF THE INVENTION
The present invention is a polyester spun yarn obtained at a take-up speed of less than 2500 m / min, and has a high residual elongation in which a filament elongation improver exhibiting a specific heat distortion temperature (T) is contained in each filament. It relates to a polyester filament yarn.
[0002]
[Prior art]
In melt spinning polyester fibers, increasing the amount of polymer discharged from the die as much as possible is an extremely effective method for improving productivity. In the recent textile industry, from the viewpoint of reducing the cost of yarn production. It is highly desirable.
[0003]
As a typical means that has been taken so far to improve the productivity, there is known a method of increasing the take-up speed in spinning and increasing the discharge amount from the die. However, in this method, since the take-up speed is fast, the molecular orientation of the individual filaments increases, and as a result, the residual elongation of the filament spun yarn obtained decreases. Therefore, as a matter of course, since the draw ratio at the time of subsequent drawing or drawing false twisting is lowered, the effect of increasing the discharge amount due to the increase in the take-up speed is offset by the drawing process.
[0004]
As one means for solving such a problem, a method for increasing the residual elongation of a spun yarn by adding an addition polymer comprising an unsaturated monomer to a polyester as a fiber elongation improver is disclosed in Japanese Patent Publication No. 63-32885. (For European Patent No. 47464 (A1)). According to this document, the function of the addition polymer is defined as being microdispersed in the molecular order in the polyester, and the polymer plays a role of “rolling” with respect to the molecular orientation of the polyester (for example, , See the above-mentioned EP patent, page 9, line 3). And as a specific example of the said addition polymer, "Delpet80n" is mentioned in the Example, When it measured actually, the heat deformation temperature was 98 degreeC.
[0005]
According to this method, an undrawn yarn having a higher residual elongation can be obtained with an increase in the take-up speed, including the intermediate oriented yarn (POY). However, at a take-off speed of less than 2500 m / min, the function as a “roller” for the molecular orientation of the polyester is reduced. Therefore, in order to express a higher residual elongation improving effect, it is necessary to add the addition polymer excessively.
[0006]
However, increasing the amount of the agent apparently improves the productivity, but the increase in the amount of the agent increases the cost, and if the agent is added excessively, the spinning condition is naturally deteriorated. . For this reason, in the current situation, true productivity improvement has not yet been achieved in the take-up speed region of less than 2500 m / min.
[0007]
[Problems to be solved by the invention]
Accordingly, an object of the present invention is to provide a polyester fiber having excellent productivity and high spinning tension under a low take-up speed of less than 2500 m / min.
[0008]
[Means for Solving the Problems]
According to the study by the present inventors, the fiber elongation improver that is substantially incompatible with polyester exhibits its function sufficiently at a take-up speed of 2500 m / min or more. That is, when passing through the cooling and thinning process on the spinning line after being discharged from the die hole, the agent transitions from the molten state to the glass state before the polyester, and against the spinning stress (tension), It plays a role as an elongation deformation resistor.
[0009]
However, the yarn speed (V) of the spun yarn and the strain speed dV / dx (here, x indicates the distance in the vertical direction from the spinneret downward), that is, the deformation speed is small 2500 m / min. In the take-up speed region below, the agent does not sufficiently function as an elongation deformation resistor. In other words, with regard to the elongation viscosity of blended yarns, non-linearity increases that do not follow the conventional elongation viscosity formula at a take-up speed of 2500 m / min or more, thereby promoting thinning and making the yarn speed of the spun yarn more spinneret. It has been found that the function of the agent to reach the take-up speed at a close position is not fulfilled.
[0010]
Accordingly, as a result of intensive investigations on the elongation improver that exhibits the above-described function even in a spun yarn with a take-up speed of less than 2500 m / min, the function is sufficiently exhibited depending on the thermal deformation temperature (T) of the agent. I found out.
[0011]
Thus, according to the present invention,
A polyester obtained by dispersing a fiber elongation improver comprising a particulate polymethyl methacrylate polymer having a thermal deformation temperature (T) in the range of 105 to 160 ° C. in an amount of 0.5 to 6.0% by weight based on the polyester weight is melt-spun. A high-elongation polyester filament yarn obtained at a take-up speed of less than 2500 m / min and having a residual elongation increase rate (I) defined below of 50% or more is provided.
[0012]
[Expression 2]

[0013]
Here, EI _b (%) is the residual elongation of the polyester filament yarn of the present invention, and EL ₀ (%) is a polyester filament obtained under the same spinning conditions as in the present invention except that it does not contain the elongation improver. This is the residual elongation of the yarn.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Melt polyester in which 0.2 to 10% by weight, based on the polyester weight, a particulate fiber elongation improver that functions as a "roller" for the molecular orientation of the polymer in the individual filaments being spun The concept of spinning to obtain a filament spun yarn (hereinafter simply referred to as spun yarn) having a residual elongation increase rate (I) of 8% or more obtained at a take-up speed of 1500 m / min to 8000 m / min. As such, it is disclosed in the above-mentioned EP 47464A specification.
[0015]
On the other hand, the present invention is left unresolved in the EP specification by specifying the heat distortion temperature (T) of the fiber elongation improver, which is not mentioned in the EP specification. Overcoming the problem of improving productivity and spinning tone by adding productivity improvers in the low take-off speed range of less than 2500m / min, that is, adding an elongation improver that has a large effect of improving the conventional elongation It is.
[0016]
First, the significance of the requirements of the present invention will be described.
In the present invention, the thermal deformation temperature (T) of the fiber elongation improver needs to be in the range of 105 to 160 ° C. in order to act on a spun yarn having a take-up speed of less than 2500 m / min. When the temperature (T) is less than 105 ° C., the function of the agent as an elongation deformation resistor is insufficient. On the other hand, when the temperature (T) exceeds 160 ° C., an excessive extensional viscosity difference is produced on the spinning line, and a sharp thinning that the spun yarn cannot follow occurs.
[0017]
Next, a polymethyl methacrylate polymer is mentioned about a fiber elongation improver.
[0018]
The specific action of these fiber elongation improvers is the sea / island state that is substantially incompatible with polyester, that is, polyester as a sea component and particulate fiber elongation improver as an island component. After being discharged, when undergoing a cooling and thinning process on the spinning line, the polyester transitions from the molten state to the glass state prior to the polyester, and plays the role of an extended deformation low antibody against the spinning stress (tension). In other words, with regard to the elongation viscosity of the blend system at a high polymer temperature in the vicinity of the die, non-linearity increases that do not follow the conventional elongation viscosity formula, and as a result, the thinning is promoted and the yarn speed of the spun yarn is discharged more The final take-up speed is reached at a position close to the hole.
[0019]
Therefore, in the fiber elongation improver having a thermal deformation temperature (T) of less than 105 ° C., the transition to the glass state is close to that of polyester, in other words, the transition to the glass state on the spinning line is slow. The role as an elongation deformation low antibody against spinning stress (tension) is not fully exhibited. Of course, when the heat distortion temperature (T) described in the above-mentioned EP specification is as low as 98 ° C., the difference from the heat deformation temperature (70 ° C.) of the polyester is even smaller at 28 ° C., so 2500 m / min. In the low take-up speed region below, the function as an elongation deformation resistor is not sufficiently exerted, and in order to develop a high elongation improving effect of 50% or more, an addition amount that affects the spinnability is required. .
[0020]
The molecular weight of these polymers preferably has a molecular weight (weight average) of at least 2000 or more because it requires the expression of structural viscoelasticity as a high molecular weight material independently of polyester as an elongation deformation resistor. In particular, 2000 to 300,000 is preferable. When the molecular weight is less than 2000, it is difficult to exhibit structural viscoelasticity as a high molecular weight body, and it is difficult to act as a stress carrier. On the other hand, when it exceeds 300,000, the cohesive energy of the polymer is extremely high, and dispersion into the polyester becomes extremely difficult. A particularly preferable molecular weight range is 10,000 to 250,000, and in the case of such a high molecular weight polymer, heat resistance is also improved.
[0021]
Specific examples of such fiber elongation improvers include those having a molecular weight of 10,000 or more and 300,000 or less and a melt index (M.M.) under the conditions (230 ° C., load 3.8 kgf) defined by ASTM-D1238. I.) is a polymethyl methacrylate copolymer or a derivative thereof having 0.5 to 15.0 g / min. The polymer having these specific physical properties exhibits excellent thermal stability and elongation improvement effect at the spinning temperature of the polyester.
[0022]
In the present invention, polyester refers to a polyester having a fiber-forming ability containing aromatic dicarboxylic acid as a main acid component. For example, polyethylene terephthalate, polytrimethylene terephthalate, polytetramethylene terephthalate, polycyclohexanedimethylene terephthalate, polyethylene- Examples include 2,6-naphthalenedicarboxylate. In addition, these polyesters may be a copolymer obtained by copolymerizing an alcohol component such as butanediol or a dicarboxylic acid such as isophthalic acid as the third component, or may be a mixture of these various polyesters. Of these, polyethylene terephthalate polymers are most suitable.
[0023]
These polyesters may contain a matting agent, a heat stabilizer, an ultraviolet absorber, an antistatic agent, a terminal terminator, a fluorescent whitening agent, and the like as necessary. These polyesters preferably have an intrinsic viscosity of 0.4 to 1.1 from the viewpoint of spinnability and yarn physical properties.
[0024]
By the way, the residual elongation improvement rate (I) of the spun yarn of the present invention is 50% or more has a correlation with the birefringence of the spun yarn. From this point, the birefringence (Δn) of the spun yarn of the present invention is preferably in the range of 0.030 or less. When Δn exceeds 0.030 at a take-off speed of less than 2500 m / min at which the effect of the present invention is exhibited, (I) is less than 70%. In addition, the elongation improver of the present invention has a heat distortion temperature (T) in the range of at least 30 ° C. higher than that of polyester. Shows excellent workability.
[0025]
Any method can be employed for adding the fiber elongation improver to the polyester. For example, the agent may be mixed at the final stage of polymerization of the polyester, or the polyester and the agent may be melt-mixed, extruded and cooled, and then cut into chips. Furthermore, the agent may be introduced from the side stream in a molten state into a polyester melt spinning apparatus via a dynamic and / or static mixture. Moreover, after mixing both in a chip shape, you may melt-spin as it is. Among them, a part of the polymer is drawn from the polyester piping of the continuous straight spinning line, and the resulting mixture is kneaded and dispersed into the original neat polymer line as an arbitrary dynamic and / or static mixture. The method of returning through the pipe and distributing to each pipe is most preferable.
[0026]
The molten polymer to which the fiber elongation improver is added as described above suppresses mixing of coarse particles into the discharged polymer stream through a filter having a pore size of 40 μm or less installed in the spin pack, and further 150 to Spinning is preferably performed under an apparent spinning draft (rate) in the range of 1500. When the spinning draft is less than 150, the polymer flow passing through the discharge hole is subjected to a high shearing force, the particulate fiber elongation improver is torn off in the longitudinal direction of the filament, and mixing of coarse particles is suppressed. The function as an elongation deformation resistor is slightly reduced, and if it exceeds 1500, the tearing effect due to the shearing force in the discharge hole is reduced, and the function as the elongation deformation resistor is improved, but coarse particles are generated. Cheap.
[0027]
Further, other preferred spinning requirements are spinning temperature (base temperature) and cooling under the spinneret.
[0028]
For the former, by lowering the die temperature at the time of discharging the molten polyester in which the fiber elongation improver is dispersed, the elongation viscosity of the elongation improver after discharging the die becomes larger upstream of the spinning line. A base temperature of 270 to 290 ° C. is particularly preferable. If it is less than 270, depending on the type of polyester, the spinnability begins to deteriorate, and if it exceeds 290 ° C., the heat resistance stability of the addition polymer as an elongation improver begins to decrease.
[0029]
In the latter case, in the case of side-blow cooling, the wind speed is preferably maintained in the range of 0.15 to 0.6 m / sec. When the wind speed is less than 0.15 m / sec, unevenness in the longitudinal direction of the filament tends to occur. On the other hand, if it exceeds 0.60 m / sec, the elongation viscosity on the polyester side increases, so the increase in the residual elongation decreases.
[0030]
The spun yarn taken up under the spinning conditions as described above may be wound through a godet roller or the like after being given an oil agent, or may be wound without passing through the roller or the like. Here, the take-off speed referred to in the present invention is the speed of the first godet roller when passing through the godet roller, and the take-up speed when not passing through the roller. Further, the spun yarn wound up in this way may be air entangled at an arbitrary position in the spinning process.
[0031]
The mode of spinning described above is applied not only when the spun yarn of the present invention is obtained alone, but also in various forms. For example, by discharging a polyester mixed with a fiber elongation improver and a polyester substantially free of the agent from the same die, it is as if compounding undrawn yarns with different spinning speeds (different elongations). It is also possible to directly scoop out the mixed yarn showing.
[0032]
【Example】
A method for measuring physical property values employed in the present invention will be described.
(1) Thermal deformation temperature (T)
Follow ASTM D-648.
(2) Birefringence of the spun yarn (Δn)
Using 1-bromonaphthalene as the penetrant, buffer fringes are measured with a polarizing microscope using monochromatic light having a wavelength of 530 nm, and the following equation Δn is calculated.
Δn = 530 (n + θ / 180) / X
n: number of stripes, θ: rotation angle of compensator, X: fiber diameter (3) Residual elongation The spun yarn was left in a room kept at a high temperature and humidity of 25 ° C. × 60% humidity for one day and then a sample A length of 100 mm is set on a tensile tester Tensilon manufactured by Shimadzu Corporation, and the tensile elongation at break is measured at a speed of 200 mm / min, that is, a strain rate of 2 min-1.
(4) According to melt index ASTM D-1238.
Hereinafter, the present invention will be described by way of examples.
[0033]
[Example 1]
A polyethylene terephthalate chip containing intrinsic viscosity 0.64, titanium oxide as matting agent and 0.3 wt% based on the weight of polyester is dried at 160 ° C. for 5 hours, and then uniaxial full flight type melt extruder having a diameter of 25 mm. Melted at 300 ° C. Next, PMMA having a heat distortion temperature (T) of 98, 105, or 121 ° C., or 3 of methyl methacrylate, an acrylimide adduct, and styrene so that the heat deformation temperature (T) is 137, 145, 160, or 168 ° C. The PMMA polymer copolymerized by changing the composition of each component was introduced from the side stream in a molten state into the molten polyester in an extruder, and then mixed and dispersed through a 12-stage static mixer. Then, after passing the polymer in the mixed dispersion state through a metal fiber filter having a pore size of 400 μm provided immediately above the die, a spinneret having 36 discharge holes having a diameter of 0.4 mmφ and a land length of 0.8 mm (L) is used. No. 1 in Table 1 shows the temperature of the molten polymer at a temperature of 285 ° C. It discharged, changing the discharge amount according to each taking-up speed as shown to 1-13. Further, 25 ° C. air was blown at a rate of 0.23 m / sec from a side-spinning spinning cooling cylinder provided below 9 cm to 100 cm below the base to cool and solidify the discharged polymer flow, and the OPU range of 0.25 to 0.30 wt%. After performing the oil agent adhesion treatment, a spun yarn of 150 denier / 36 filaments was wound in an unstretched state. The results are shown in Table 1.
[0034]
[Table 1]

[0035]
Table 1 is considered below.
[0036]
In Nos. 1-4, 12 and 13, if the effect of Tg is compared, the elongation improvement effect is improved as Tg increases, and the residual elongation improvement rate is 50 except for No. 1 where the Tg of PMMA is low. % Higher elongation improvement effect and stable spinning tone. On the other hand, in No. 7, although the Tg of PMMA satisfies the requirements of the present invention, the amount of addition is small, so that a sufficient effect of improving the elongation cannot be achieved, and Δn also exceeds 0.030. Further, No. 11 had a large addition amount, so that single yarn breakage occurred. No. 13 had a Tg of 168 ° C. and a PMMA polymer was added.
[0037]
[Example 2]
PMMA polymer (heat distortion temperature) obtained by copolymerizing three components of methyl methacrylate, acrylic imide and styrene using a spinneret having 36 discharge holes with a diameter of 0.3 mmφ and a land length of 0.6 mm (L) (T): 137 ° C., melt index 230 ° C., load 3.8 kg at 0.8 g / 10 min) was added in the same manner as in Example 1, except that 4% by weight was added as a fiber elongation improver. No. 2 shown in FIG. While adjusting the discharge amount so as to obtain each denier of 14 to 16, it was wound at a take-up speed of 1500 m / min. The results are shown in Table 2.
[0038]
[Table 2]

[0039]
Table 2 is considered below.
No. examined for denier dependence. In 14 to 16, a fine denier material in which the cooling of the polymer flow discharged from the die is easy to proceed has a greater effect of improving the elongation. This is presumed that the action of the PMMA polymer as an elongation deformation resistor was reinforced by cooling.
[0040]
This phenomenon is completely different from the denier dependence of polyesters that do not contain addition polymers that are incompatible with conventional polyesters.
[0041]
【The invention's effect】
A conventional fiber elongation improver is sufficient by adding and dispersing a particulate fiber elongation improver having a heat distortion temperature (T) in the range of 105 to 160 ° C. in an amount of 0.5 to 6.0% by weight based on the polyester weight. Even in the take-up speed region where the function is not exhibited and the take-up speed is less than 2500 m / min, a high elongation improvement effect can be achieved. Therefore, there is provided a polyester filament yarn having improved productivity and spinning tone that is highly stretched with an addition amount smaller than the conventional amount.

Claims (5)

A polyester obtained by dispersing a fiber elongation improver comprising a particulate polymethyl methacrylate polymer having a thermal deformation temperature (T) in the range of 105 to 160 ° C. in an amount of 0.5 to 6.0% by weight based on the polyester weight is melt-spun. A high elongation polyester filament yarn obtained at a take-up speed of less than 2500 m / min and having a residual elongation increase rate (I) defined below of 50% or more.
However, said (I) follows the following formula | equation.

Here, EI _b (%) is the residual elongation of the polyester filament yarn of the present invention, and EL ₀ (%) is the same as that of the present invention except that the fiber elongation improver comprising the polymethyl methacrylate polymer is not included. It is the residual elongation of the polyester filament yarn obtained under spinning conditions. The high elongation polyester filament yarn according to claim 1, wherein the fiber elongation improver comprising the polymethyl methacrylate polymer has a heat distortion temperature (T) in the range of 115 to 155 ° C.   The high elongation polyester filament yarn according to claim 1, wherein the birefringence (Δn) of the filament yarn is in the range of 0.006 to 0.030. The high elongation polyester filament yarn according to claim 1, wherein the fiber elongation improver comprising the polymethyl methacrylate polymer has a molecular weight of at least 2000 or more. The fiber elongation improver made of the polymethyl methacrylate polymer has a molecular weight of 10,000 to 300,000 and a melt index (230 ° C., load 3.8 kg) of 0.2 to 6.0 g / 10 min. The high elongation polyester filament yarn according to claim 4, which is a polymethyl methacrylate polymer as a main component.