JPH0366403B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field] The present invention relates to a method for producing a polyester multifilament. More specifically, we can stably produce multifilament yarns for high-quality textiles with a fineness called fine denier yarn, which has a total number of 40 or more filaments (hereinafter referred to as single yarns) and a single yarn fineness of 1.5d or less. It relates to a manufacturing method. [Prior Art and Its Problems] Many studies have been conducted on yarns for high-grade textiles, but it is known that pin-drawn polyester fine denier yarns are most suitable. However, when a multifilament yarn with a total number of single yarns of 40 or more and a single yarn fineness of 1.5d or less is pin-drawn, the single yarns overlap on the drawing pin, and the drawing pin The yarn temperature of the outer single yarns that are not in direct contact with the surface did not reach the specified temperature, which caused stretching unevenness, fluff, and sagging. Therefore, the present inventors attempted to draw fine denier yarn using a heated rotating roller without using a drawing pin. A method of stretching using heated rotating rollers is proposed, for example, in Japanese Patent Publication No. 43-19109. This method is called ``When drawing polyester fibers between a heating supply roller and a drawing roller, a preliminary tension of 10 to 90% of the net drawing starting tension is applied before stretching, and then the surface temperature T of the heating supply roller is adjusted to The temperature is set to 10 to 55 degrees Celsius higher than the secondary transition temperature (Tg) of the yarn, and the time t during which the yarn contacts the heating supply roller satisfies the formula t≧-0.007 (T-Tg) + 0.485. In addition, when pressing the elastic roller onto the heating supply roller, the angle (α) formed by connecting the point where the elastic roller contacts the heating supply roller, the yarn separation point, and the axis is an angle of 0 to 20°. A stretching method characterized in that the stretching method is within a range of This method is more effective than the method using a drawing pin to obtain a uniformly drawn yarn with fewer drawing irregularities, but since the elastic roller pressed onto the heating supply roller gradually undergoes thermal deterioration and hardens. In order to achieve the initial goal, maintaining the functionality of the elastic rollers is complicated and very expensive as an industrial production process. In addition, when drawing filament denier yarn, it is virtually impossible for the individual filaments to completely open on the heated supply roller and come into direct contact with the surface of the heated supply roller. The temperature of the outer filament that is not in direct contact with the roller surface in the overlapping filaments tends to be lower than that of the inner filament that is in direct contact with the roller surface, and therefore the drawing point is very small between the individual filaments. When dyed, some of the individual filaments constituting the multifilament yarn are dyed darkly, causing minute stretching irregularities, fuzz, and sagging. In addition, fine denier yarn is often used as yarn for high-quality textiles, but for example, high-quality textiles such as Fuji silk, dechine, and Yangyanagi have minute irregularities called jibo and shrinkage on the surface of the textile. , it has wrinkles, which gives the fabric its fullness, warmth, deep luster, etc., and is the reason why it has a high-class image. In order to achieve this, the heat shrinkage stress of the yarn is preferably 0.48 g/d or more, more preferably 0.50 g/d or more. However, the heat shrinkage stress level of a multifilament preheated and drawn with a heating supply roller without using a drawing pin is about 0.40±0.05 g/d, and a drawn yarn that is desirable as a raw yarn for high-grade textiles cannot be obtained. be. [Object of the Invention] The object of the present invention is to improve the drawbacks of the prior art, and to produce a fineness of 1.5 d or less and a filament number of 40 or more, which is substantially free from drawing unevenness, fluff, and sagging. The present invention provides a method for producing denier yarn in an extremely stable manner. [Structure of the Invention] In order to achieve the above object, the present invention has the following structure. That is, when drawing a polyester multifilament undrawn yarn having a total number of 40 or more filaments to obtain a drawn yarn with a filament fineness of 1.5d or less, the undrawn yarn is heated to the range of the following formula (1). The first stage of stretching is carried out at a stretching ratio within the range of formula (2) below.
Subsequently, manufacturing a polyester multifilament characterized by heating with a heated stretching roller heated to the range of the following formula (3), performing a second stage stretching at a stretching ratio within the range of the following formula (4), and then winding it up. It's a method. Tg＋5＜T ₁ ＜Tg＋30 ……(1) NDR≦DR ₁ ＜0.95TDR ……(2) Tg＜T ₂ ＜Tg＋50 ……(3) DR ₂ ≦TDR／DR ₁ ……(4) [Tg: Glass Transition temperature (°C) T ₁ : Surface temperature of heated rotating roller (°C) T ₂ : Surface temperature of heated drawing roller (°C) NDR: Natural stretching ratio of undrawn yarn TDR: Upper limit appropriate ratio of undrawn yarn DR ₁ : First stage stretching ratio _DR2 : Second stage stretching ratio] The present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram of a manufacturing process showing one embodiment of the present invention. In Fig. 1, the undrawn yarn Y is pulled out from the undrawn yarn drum, fed at a constant speed by a pressing roller 1 and a feed roller 2, and then wound around a heated rotating roller 3 heated to the range of formula (1) above. After sufficient preheating, the sheet is guided to a heated stretching roller 4, and a first stage of stretching is carried out between the heated rotating roller 3 and the heated stretching roller 4 within the range of formula (2). Subsequently, it is wound around the heated stretching roller 4 heated to the range of formula (3) above, and after being sufficiently preheated, it is guided to the stretching roller 5, and between the heated stretching roller 4 and the stretching roller 5, the 4) The second stage of drawing is carried out within the range of the formula, and the drawn yarn is wound around a cheese 7 using a drive roller 6. The stretching roller 5 may be at room temperature, or may be heated for heat treatment if necessary. When the drawing roller 5 is used at a temperature below Tg, it is preferable that the yarn exiting the drawing roller 5 is subjected to an entangling process using a fluid turbulence nozzle (not shown) and then wound. On the other hand, when the drawing roller 5 is used at a temperature higher than Tg, after the yarn exiting the drawing roller 5 is subjected to an entangling process using a fluid turbulence nozzle, a cooling roller (not shown) is used for the purpose of cooling the yarn. It is preferable to wind it up and run it, and then wind it up. Further, as a winding method, as shown in FIG. 1, it can be wound around a drawn yarn cheese 7 using a drive roller 6, or it can be wound into a pirn shape using a twister using spindle rotation. In the present invention, the surface temperature of the heated rotating roller 3
It is necessary to set T ₁ to Tg+5<T ₁ (°C)<Tg+30. If the temperature of the heating rotating roller is less than (Tg + 5°C), the preheating effect of the undrawn yarn will be insufficient, and drawing unevenness, fluff, and sagging will easily occur.
(Tg + 30)°C or higher, the undrawn yarn becomes soft when it is wound around a heating rotating roller and preheated, and the yarn tension on the roller decreases. As the vibration increases and the yarn twitches at the point where the yarn separates from the roller welding running section, drawing unevenness, fluff, and sagging increase, the surface temperature of the heating rotating roller increases as described in (1) above. The formula must be in the range Tg+5<T ₁ <Tg+30. Also, the first stage draw ratio DR ₁ is the natural draw ratio NDR.
If it is less than the upper limit appropriate stretching ratio TDR, an unstretched portion will remain in the yarn after the first stage drawing, and even if the second stage drawing is carried out, the sufficient effect aimed at by the present invention will not be obtained. If it is 0.95 times or more, the ratio of the first stage drawing ratio is too high, and the effect of the second stage drawing becomes insufficient, making it difficult to obtain a yarn without drawing unevenness, fuzz, or sag, which is the objective of the present invention. Since it _becomes difficult to
Must be in the range NDR≦DR ₁ <0.95TDR. In addition, in the conventional method of stretching the undrawn yarn to an appropriate stretching ratio using only the first stage stretching ratio, it is possible to achieve extremely high quality, which is the objective of the present invention, and a heat shrinkage stress of 0.45 g/ It was virtually impossible to obtain a drawn yarn with a diameter of d or more. but,
After carrying out the first stage stretching under conditions that satisfy the above formulas (1) and (2), the second stage stretch ratio DR ₂ and heated stretching roller temperature T ₂ are determined according to the formulas (3) and (4) above, that is, Tg＜ _T2 ＜Tg＋
50, By carrying out the second-stage stretching under conditions that satisfy the range of DR ₂ ≦TDR/DR ₁ , the stretching irregularities that occurred in the first-stage stretching are selectively re-stretched, so that stretching irregularities and A drawn yarn without fluff or sag can be obtained. At the same time, by further hot-drawing the drawn yarn, which has been drawn to a ratio of NDR or higher in the first stage drawing and has undergone considerable crystallization and orientation, the crystallization is improved compared to when the drawing is completed only in the first stage drawing. growth is promoted, the ability to develop heat shrinkage stress in the drawn yarn increases,
0.45 g/d or more as the objective of the present invention, and even 0.50 g/d
A drawn yarn having a heat shrinkage stress of more than g/d can be obtained. When the heated stretching roller temperature T ₂ in the second stage stretching is below Tg, the growth of crystals becomes insufficient and the thermal shrinkage stress decreases. On the other hand, when it is above (Tg + 50)°C, crystal growth increases rapidly. , leading to deterioration of stretchability,
Since fuzz occurs due to single yarn breakage, the heating stretching roller temperature T ₂ must be within the range of formula (3) above. If the product of the draw ratio DR ₁ in the first stage and the draw ratio DR ₂ in the second stage exceeds the upper limit value TDR of the appropriate ratio range for undrawn yarn, the occurrence of fuzz due to single yarn breakage will increase. The draw ratio DR ₂ in the second stage, together with the draw ratio DR ₁ in the first stage, must be within the range of the upper limit appropriate ratio TDR of the undrawn yarn, that is, within the range of formula (4) above. Here, the measurement method and calculation method for the natural draw ratio NDR and upper limit appropriate ratio TDR of the undrawn yarn shown in the present invention will be explained with reference to the drawings. FIG. 2 is a graph showing the relationship between tensile strength and elongation when an undrawn yarn is subjected to a tensile test using a Tensilon type universal tensile tester. In Fig. 2, curve S is the tension-elongation curve when undrawn yarn is pulled to the breaking point, point A is the pulling start point, point B is the elongation corresponding to the natural stretching ratio of the undrawn yarn, and point C is the elongation curve. Point D indicates the elongation corresponding to the upper limit appropriate ratio of the undrawn yarn, and the elongation corresponding to the break point of the undrawn yarn. ) is below
Values calculated using equations (5) and (6). However, the appropriate magnification range is the range where the elongation of the drawn yarn is 20 to 50%, and the upper limit appropriate magnification (TDR) is the magnification where the elongation of the drawn yarn is 20%. NDR=1+l _B ×V ₁ /l ₀ ×V ₂ ...(5) TDR=1+l _C ×V ₁ /l ₀ ×V ₂ ...(6) However, V ₁ = tensile speed of tensile testing machine (cm/min ) V ₂ = Chart speed of recorder (cm/min) l ₀ = Undrawn yarn sample length (cm) l _B = Distance from point A to point B (cm) l _C = Distance from point A to point C (cm) Next, the polyester multifilament undrawn yarn used as the raw material of the present invention uses terephthalic acid as the main dibasic acid, and as the glycol, ethylene glycol or cyclohexanedimethanol is used as the main glycol, or ethylene oxy It uses benzoate and is copolymerized with 3 to 15 mol% of a third component such as oxalic acid, sebacic acid, phthalic acid, isophthalic acid, etc. for the purpose of imparting high shrinkage properties, etc., and for the purpose of imparting easy dyeability. polyethylene oxide, polypropylene oxide,
Polyethylene glycol, sodium m-phenolsulfonate, sodium m-(β-oxyethoxy)benzenesulfonate, sodium 3,5-dicarbomethoxybenzenesulfonate, dimethyl-5-sodium sulfoisophthalate, bis(β-hydroxyethyl )-5-sodium isophthalate, etc., may be copolymerized with 1 to 10 mol % of a third component, or 0 to 5 mol % of titanium oxide may be copolymerized for the purpose of matting effect or improving yarn reeling properties. Furthermore, the cross-sectional shape of the multifilament may be a circular cross-section or an irregular cross-section (3
It is valid regardless of the shape (angular, pentagonal, octagonal, etc.). The heat shrinkage stress in the present invention was measured by the following method. [Heat shrinkage stress measurement method] Set on a strain meter with a sample length of 100 mm and an initial load of 30 mg/d.
From room temperature to 250℃ at a heating rate of 2.5℃/sec under dry heat conditions
Record the change in contractile force with an X-Y recorder when the temperature is raised to MAX.
Read the stress and peak temperature, and use the value calculated in (7) below as the heat shrinkage stress. Heat shrinkage stress (g/d) = MAX stress (g)/drawn yarn denier (d)... (7) [Effects of the invention] By adopting the above structure, the heat shrinkage stress is reduced to 0.45 g/d. It is possible to stably obtain a uniform polyester multifilament drawn yarn having a polyester multifilament ratio of d or more and substantially free from drawing unevenness, feathering, and sagging. The present invention will be explained below using examples. Example 1 A polyester chip with an intrinsic viscosity of 0.65 (measured in orchlorophenol at 25°C) was spun at a spinning temperature of 293°C and a spinning speed of 1480 m/min using a spinneret with 72 circular holes and a triangular hole. , denier 218D, glass transition temperature 70℃, natural stretch ratio
An undrawn yarn with an upper limit appropriate magnification of 3.11 times and a breaking elongation of 345% was obtained. The undrawn yarn was drawn in the manufacturing process shown in FIG. 1 at a drawing speed of 800 m/min under the conditions shown in Table 1, and the resultant drawn yarn was evaluated for fuzz and fuzz by heat shrinkage stress measurement, Worcester unevenness measurement, and warping test. The results shown in Table 1 were obtained by measuring the sagging, visual judgment using a magnifying glass of the minute dark dyed filaments when weaving and dyeing, and visual judgment of the texture when finished into a textured fabric. Note that T ₁ , T ₂ , defined by formulas (1) to (4) of the present invention,
and DR ₁ values are 75<T ₁ <100, 70<T ₂ respectively
<120 and 2.41≦DR ₁ <3.05 and DR ₂ is DR ₁
It is defined as follows:

【table】

[Table] Overall judgment criteria ◎: Very good ○: Good ×: Poor In Table 1, Experiment No. 1, 5, 6, 9, 10, 13
and 15 are comparative examples for clarifying the effects of the present invention. Experiments Nos. 1 to 5 confirmed the effect of the surface temperature T ₁ of the heating circuit roller for drawing in the first stage.
In Nos. 2, 3 and 4, good drawn yarns, which are the object of the present invention, were obtained, whereas in No. 1, the temperature was low, so drawing unevenness was likely to occur due to insufficient preheating between the filaments. , there was an increase in Worcester's unevenness and the occurrence of darkly dyed filaments, fuzz, and sagging.On the other hand, in No. 5, due to the high temperature, yarn wobbling on the heated rotating roller and yarn twitching at the yarn separation point occurred. This resulted in drawing unevenness, an increase in Worcester's unevenness, and the occurrence of darkly dyed filaments, fluff, and sagging, and the drawn yarn that was the object of the present invention could not be obtained. Experiments Nos. 6 to 9 confirmed the effect of the surface temperature _T2 of the heated stretching roller for second stage stretching.
In Nos. 7 and 8, good drawn yarns, which are the object of the present invention, were obtained, whereas in No. 6, the temperature was low, so the heat shrinkage stress level was low, and therefore the fabric did not develop wrinkles. In No. 9, the temperature was high, so the rate of crystallization progressed quickly, resulting in poor drawability, increased fuzz, and the drawn yarn that was the object of the present invention could not be obtained. Experiment Nos. 10 to 13 confirmed the effect of the drawing ratio in the first stage, but in No. 11 and No. 12, good drawn yarn, which is the objective of the present invention, was obtained. ,
In No. 10, the drawing ratio in the first stage is lower than the natural drawing ratio NDR of the undrawn yarn, so drawing unevenness occurs, increasing Worcester unevenness, dark dyed filaments, fuzz/sagging, etc. , No. 13 is stretched at a magnification of 0.95TDR or more in the first stage, so the effect of two-stage stretching cannot be obtained, and therefore the heat shrinkage stress level is low, which is not the stretching target of the present invention. No thread was obtained. Experiment Nos. 14 and 15 confirmed the upper limit of the appropriate magnification and the limits of the first and second stage stretching ratios, and in No. 14, the drawn yarn targeted by the present invention was obtained. On the other hand, in No. 15, the combined stretching ratio of the first stage and second stage was stretched beyond the upper limit of the appropriate ratio range, so fluff and sagging occurred, which is the object of the present invention. No drawn yarn was obtained. Experiment No. 16 was conducted under the same conditions as No. 3 to confirm the effect of air entanglement treatment for the purpose of imparting convergence and improving passage through higher-order processing steps.
Like 3, it is extremely good, especially the texture of the fabric is No.
It was better than 3. No.17 and No.18 are threads with triangular cross section.
Although the yarns were drawn under the same conditions as No. 16, good drawn yarns, which are the object of the present invention, were obtained in all cases.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a manufacturing process showing one embodiment of the present invention. Figure 2 shows the NDR shown in the present invention.
In order to explain TDR, it is a graph showing the relationship between tensile tension and elongation. 1: Nitz roller, 2: Feed roller, 3:
heating rotating roller, 4: heated drawing roller, 5: drawing roller, 6: drive roller, 7: drawn yarn cheese, Y: undrawn yarn.

Claims (1)

[Scope of Claims] 1. When drawing a polyester multifilament undrawn yarn having a total number of 40 or more filaments to obtain a drawn yarn with a filament fineness of 1.5d or less, the undrawn yarn is subjected to the following (1). The material is heated with a heated rotating roller heated to the range of formula (2), and the first stage of stretching is performed at a draw ratio in the range of formula (2) below.Subsequently, the material is heated with a heated stretching roller heated to the range of formula (3) below. A method for producing a polyester multifilament, which comprises stretching the polyester multifilament in a second stage at a stretching ratio within the range of formula (4) below, and then winding it up. Tg＋5＜T ₁ ＜Tg＋30 ……(1) NDR≦DR ₁ ＜0.95TDR ……(2) Tg＜T ₂ ＜Tg＋50 ……(3) DR ₂ ≦TDR／DR ₁ ……(4) [Tg: Glass Transition temperature (°C) T ₁ : Surface temperature of heated rotating roller (°C) T ₂ : Surface temperature of heated drawing roller (°C) NDR: Natural stretching ratio of undrawn yarn TDR: Upper limit appropriate ratio of undrawn yarn DR ₁ : 1st stage stretch ratio DR ₂ : 2nd stage stretch ratio]