US3886722A

US3886722A - Process for producing polyester textured yarn

Info

Publication number: US3886722A
Application number: US387629A
Authority: US
Inventors: Kikuo Hori; Hidehiko Okada; Masakazu Fujita
Original assignee: Teijin Ltd
Current assignee: Teijin Ltd
Priority date: 1972-08-17
Filing date: 1973-08-13
Publication date: 1975-06-03
Anticipated expiration: 1992-06-03
Also published as: FR2196407A1; BR7306322D0; GB1436748A; FI54501B; JPS4936921A; FR2196407B1; FI54501C; DE2341748A1; TR17638A; NL7311385A; IT998372B; CS202026B2

Abstract

A process for producing a polyester textured yarn which comprises drawing and simultaneously false-twisting an undrawn polyester yarn using a draw texturing apparatus equipped with a heat-treating heater and a false twister between feed rollers and draw rollers, wherein the undrawn polyester yarn has a birefringence ( Delta n) of 0.01 to 0.05, and the draw ratio (DR) is adjusted to a value expressed by the following equations according to the birefringence of the undrawn polyester yarn -1.8349 LOG Delta N-1.1376 < OR = DR < OR = -2.1789 log Delta n-1.3509 AND DR < OR = 2.8.

Description

United States Patent [191 Hori et al.

[ June 3, 1975 1 PROCESS FOR PRODUCING POLYESTER TEXTURED YARN [75] Inventors: Kikuo Hori; Hidehiko Okada;

Masakazu Fujita, all of Matsuyama, Japan [73] Assignee: Teijin Limited, Osaka, Japan [22] Filed: Aug. 13, 1973 [21] Appl. No.: 387,629

[30] Foreign Application Priority Data Aug. 17, 1972 Japan 47-81782 [52] US. Cl 57/157 TS [51] Int. Cl D02g 1/00 [58] Field of Search 57/34 HS, 157 R, 157 S, 57/157 TS, 157 MS, 160

[56] References Cited UNITED STATES PATENTS 3,090,997 5/1963 Tin-Yam Au 57/157 S UX 3,137,991 6/1964 Fairley 57/160 3.400,]94 9/1968 Boone et a1. 57/157 S X 3,481,136 12/1969 Timmons et a1 57/157 S X 3,691,750 9/ l 972 Waters 3.780515 12/1973 Waters 57/157 R Primary ExaminerDonald E. Watkins Attorney, Agent, or Firm-Sherman & Shalloway [57] ABSTRACT A process for producing a polyester textured yarn which comprises drawing and simultaneously falsetwisting an undrawn polyester yarn using a draw texturing apparatus equipped with a heat-treating heater and a false twister between feed rollers and draw rol-' lers, wherein the'undrawn polyester yarn has a birefringence (An) of 0.01 to 0.05, and the draw ratio (DR) is adjusted to a value expressed by the following equations according to the birefringence of the undrawn polyester yarn -l.8349 log 'A nl.l376 DR and 2.l789 log A 17 Claims, 5 Drawing Figures PATEIHEBJUHB 197s 3.886722 SHEET 2 DRAW RATIO BIREFRINGENCE (AD) Fig. 5 6.0" I

|s0 I250 TEMPERATURE OF HEAT-TREATING HEATER ('0) DEGREE OF DYE EXHAUSTION PROCESS FOR PRODUCING POLYESTER TEXTURED YARN This invention relates to a method of producing polyester textured yarns. More specifically; this invention relates to a method of producing textured yarns which comprises drawing an undrawn yarn of a polyester using a draw texturing apparatus including a heattreating heater and a false twister between feed rollers and draw rollers, and simultaneously false-twisting it to form a textured yarn.

In recent years, a method of producing a textured yarn from an undrawn yarn in a single step has been in use, in which an undrawn yarn of polyester is drawn and simultaneously twisted. Although this method is very efficient as compared with the conventional method in which drawing and twisting are performed separately, there is a defect that because of the occur rence of fluffs, loops, tight spots, dyeing unevenness, etc., textured yarns of fully satisfactory quality cannot be obtained.

It is an object of this invention to provide a drawtexturing process capable of providing textured yarns free from these defects.

We have found that the above object can be achieved by selecting an undrawn yarn of a specific birefringence and a specific draw ratio is selected according to the birefringence of the undrawn yarn.

According to this invention, there is provided a method of producing polyester textured yarns which comprises drawing and simultaneously false twisting an undrawn yarn of a polyester using a draw texturing apparatus equipped with a heat-treating heater and a false twister between feed rollers and draw rollers, wherein the undrawn yarn of polyester has a birefringence (An) of 0.01 to 0.05, and the draw ratio (DR), that is, the ratio of the peripheral speed of the draw rollers and that of the feed rollers. is adjusted to a value which satisfy the following equation according to the birefringence of the undrawn yarn l.8349 logAn 1.1376 DR 2.l789 logAn The polyester undrawn yarn," as used in the present specification and appended claims, generically denotes a substantially unoriented multifilament yarn composed of polyethylene terephthalate or a copolymer at least 85 mol of which are ethylene terephthalate units. The denier, and cross sectional configuration of the multifilament yarn and the addition of an additive thereto. etc. can be selected as desired. For textured yarns having good feel, undrawn yarns having a denier size of 30 to 1,000 denier are especially preferred.

In the present invention, the polyester undrawn yarns having a birefringence (An) of 0.01 to 0.05, preferably 0.01 to 0.025, are used. The birefringence of the undrawn yarn varies according to such factors as the composition, and inherent viscosity of the polyester, the spinning temperature, spinning speed, or the cooling conditions. By controlling these conditions, undrawn yarns having a birefringence of 0.01 to 0.05 can be easily produced. 7

For example, when polyethylene terephthalate having an inherent viscosity (as measured in ochlorophenol at 35C.) of 0.6 is spun at 300C. using a conventional spinning apparatus, and wound up at various rates, the birefringence of the resulting filament changes as shown below.

Windup rates If an undrawn yarn of polyester in this invention is less than 0.01, breakage of the yarn frequently occurs at the time of yarn stringing, and the efficiency of the yarn stringing and the productivity become poor. In addition, tight spots tend to occur and the undrawn yarn drastically changes with the passage of time, making it impossible to produce a textured yarn of uniform quality. On the other hand, with an undrawn yarn having a birefringence exceeding 0.05, non-uniformity in the spinning process is remarkable, and this non-uniformity cannot be obviated even by draw texturing techniques. thus making it impossible to give a textured yarn of uniform quality.

In the present invention, it is preferred that an undrawn polyester yarn which has been subjected to aging under the temperature (TC.)-time (2 hours) conditions be submitted to a draw texturing process. In this case, a textured yarn having especially reduced occurrence of dyeing unevenness can be obtained.

Aging conditions:

where 20C. T 30C., (2.604 0.0486T) I 2ll.2T+ 6424 where 30C T 40C., (2.604 0.04867") An alternative method of obtaining a textured yarn having especially reduced occurrence of dyeing uneveneness involves the use of an undrawn polyester yarn whose moisture content is maintained always at not more than 1.0% preferably not more than 0.5%, during the period from the end of spinning until the draw texturing process. Adjustment of the moisture content of the undrawn yarn to such a low value can be easily achieved by treating the undrawn yarn with an oiling agent having a low moisture content or having substantially no moisture content in the spinning step.

FIG. 1 is a side elevation in simplified form of a suitable apparatus for performing the method of the invention;

FIG. 2 is a sectional view illustrating a preferred embodiment of this invention for performing the method of this invention using a modified hot-plate type heater;

FIG. 3 is a graphic representation showing the relation between draw ratio, and birefringence;

FIG. 4 is a side elevation illustrating still another embodiment of an apparatus usable in this invention;

FIG. 5 is a graphic representation showing the relationship between yarn parameters of this invention.

FIG. 1 of the accompanying drawings is a side elevation in simplified form of one example of a suitable apparatus for performing the method of this invention. In FIG. 1, the'reference numeral 1 shows a package of an undrawn yarn; 2, a tensioner; 3, feed rollers; 4, a heattreating heater; 5, a false-twisting spindle; 6, draw rollers; and 7, a winder. The undrawn yarn is withdrawn from the package 1, and fed at a constant speed by the feed rollers 3 via the tensioner 2. After making sliding contact with the heat-treating heater 4, the undrawn yarn passes the false twisting spindle and reaches the draw rollers 6 which rotate at a constant speed faster than the speed of the feed rollers. During this time. the undrawn yarn is drawn at a draw ratio (DR) corresponding to the ratio of peripheral speed between the draw rollers 6 and the feed rollers 3, and the false twists given to the yarn by the false-twisting spindle 5 are heat-set by the heat-treating heater 4. The false twists are detwisted after passage of the yarn through the false twisting spindle 5. The position of the undrawn yarn on the heat-treating heater is fixed by a guide located upwardly of the heater 4 and a guide located downwardly of the heater 4, and the feeding position of the yarn to the false twisting spindle 5 is fixed by a guide located upwardly of the spindle 5. The drawn yarn which has left the draw rollers 6 develops crimps -while being wound up by the winder 7 after passing the guide. The draw texturing speed is usually 75 to 600 m/min.

The heat-treating heater is not limited to a hot plate type as shown in FIG. 1, but other known types such as a slit heater or tube heater can be used. Preferably, the temperature of the heat-treating heater is 160 to 210C. When temperatures within this range are employed, textured yarns having especially good leveldyeability and crimp properties with extremely reduced occurrence of fluffs or tight'spots can be obtained.

According to another preferred embodiment of this invention, the surfaces of the feed rollers 3 are maintained at a temperature of 60 to 120C., and the undrawn yarn is brought into contact with the surfaces for at least 0.05second. By this procedure, the point of drawing is fixed between the feed rollers 3 and the heat-treating heater 4,'and the occurrence of drawing uneveaeness, dyeing uneveneness, yarn breakage, and fluffs, etc., is remarkably reduced.

' FIG. 2 of the accompanying drawings is a sectional view for illustrating a preferred embodiment of this invention for performing the method of this invention using a modified hot plate-type heater 4' instead of the hot plate shown in FIG. 1. In FIG. 2, the reference numeral 1 shows an. undrawn yarn, and the reference numeral 9 shows one member of a pair of walls arranged in parallel with each other with a slit therebetween in the longitudinal direction of the heater 4'. In this embodiment, the undrawn yarn 1 does not come into contact with the heated surface of the heater from the inlet of the heater to a position apart from it by distance I mm., but is preheated at a temperature of 60 to 150C. within the slit space confined by the wall 9. The undrawn yarn is subsequently brought into contact with the heated surface of the heater. The distance I should satisfy the following equations.

and

0.03 .r 0.2 1 51 0.3x 2y 100 wherein x is the denier size of the undrawn yarn. and y is the feed rate (m/min) of the undrawn yarn. If the undrawn yarn is heat-treated under theseconditions, the point of drawing is fixed between the point ofinitial contact of the undrawn yarn with the heated surface of the heater and a point 30 mm away from it. and therefore, a textured yarn having especially superior crimp properties and reduced occurrenceof tight spots, dyeing uneveneness and fluffs can be obtained.

The rotating speed of the false-twisting spindle 5 is preferably controlled such that the twist multiplier a expressed by the following equation is within the range of 0.85 and 1.15.

wherein .r is the number of false twists (T/M), and De is the denier of the drawn yarn.

It is essential in the present invention that the ratio of the periperal speed of the draw rollers 6 to that of the feed rollers S, that is, the draw ratio (DR), be adjusted to a value expressed by the following equations according to the birefringence (A n) of the undrawn yarn, for example within the range of 2.2 to 2.8. l.8349 logAn 1.1376 5: DR -2.l789 logAn FIG. 3 of the accompanying drawings is a graphic representation showing the relation between the draw ratio and the birefringence. In performing the method of this invention, the draw ratio and birefringence values within the hatched area in FIG. 3 should be selected. If the draw ratio is lower than this range, the un drawn yarn melt-adheres onto the heat-treating heater, and yarn stringing is difficult. Moreover, the level-dyeability becomes poor, and the tenacity is reduced. On the other hand, if the draw ratio is higher than the range specified above, fluffs and loops tend to occur, and the crimp characteristics of the yarn become poor. Furthermore, when the draw ratio becomes too high, the tenacity of the yarn rather decreases.

As is clear from FIG. 3,the draw ratio employed in the method of this invention is considerably lower than those employed in usual drawing processes. It is surprising that in spite of the use of such low draw ratios, the method of this invention makes it possible to give a texture yarn having no fluffs or loops and having superior level-dyeability, methanical properties and crimp characteristics.

Another embodiment is possible in this invention in which at least 2 yarn guides are provided between the false twister and the draw rollers to bend the yarn at a certain angle, and the total sum of the bended angles caused by these guides is adjusted to 30 to 270C,

preferably 30 to FIG. 4 is a side elevation illustrating this embodiment of this invention. The reference numeral shows a false twisting spindle, the

reference numerals

8, 8 and 8" show yarn guides, and the reference numeral 10 designates draw rollers. Of course, the draw rollers 10 may be replaced by the draw rollers 6 shown in FIG. 1. In this embodiment also, it goes without saying that package tensioner 2, feed rollers 3, heat-treating heater 4, winder 7, etc. must be arranged as shown in FIG. 1.

According to this embodiment. as shown in FIG. 4, at least two

yarn guides

8, 8', 8" are provided between the false twisting spindle 5 and the draw rollers 10, and the total sum of the bended angles 01,. a a (Ea) is adjusted to 30 to 270, preferably 30 to 150. This total sum of the bended angles is very important for detwisting the false twists completely and-exhibitingthe'crimp characteristics fully. If the total sum is less than 30, the false twistsare not sufficiently detwisted, and tight spots occur partly in the lengthwise direction of the yarn. On the other hand. if the total sum exceeds 270, resistance caused by the guides becomes excessive, and fluffs occur. Furthermore, the crimp characteristics become poor. However, if the total sum is within the range specified in this invention, the false twists are completely detwistdd, and the crimp characteristics are improved and the occurrence of ballooning is very much reduced. Furthermore, the number of the yarn guides is also of importance. If it is only one, uniform detwisting can not be performed even if the bended angle of the yarn is adjusted to more than 30. In order to give a bended angle of more than 30 using one guide, the guide must be provided at a position greatly deviated from the center of the false twisting spindle. However, if it is disposed in such a way, the yarn comes into contact with the edge of the spindle and excessive load is exerted on the yarn, which in turn becomes a cause of fluffs and poor crimps. Accordingly, it is necessary to provide at least two yarn guides.

False twisting can also be performed using known false-twisting means, for example, by applying friction or by a swirling flow of fluid. In the example shown in FIG. 4, the bended direction of the yarn is at right angles to the axial direction of the draw rollers, but may be in the parallel direction to the axial direction of the draw rollers. Further, bendings in both directions may be combined as desired.

The shape and dimension of the yarn guide are not particularly restricted, but preferably, the guide nearest the false twister is an annular guide, and the other guides are rod-like guides. Further, the guides may be either fixed guides or rotating guides. The surface of the guides may either be smooth or embossed. However, especially by using fixed guides with smooth surfaces of not more than 18, the effect of preventing tight spot is remarkable. In addition, by the contacting effect of the guides, the crimp characteristics of the yarn are improved to a great degree. The material of the guides may be those conventionally used, for example, saphire, titanium porcelain, alumina porcelain, or chrome-plated metals.

According to another embodiment of this invention, the process is controlled so that the yarn is made to run in air at room temperature for 0.13 to 0.3 second between the heat-treating heater and the false twister. This makes it possible to obtain a textured yarn having high degrees of crimp and crimp fastness and reduced tight spot.

According to still another embodiment of this invention, a second heat-treating heater (not shown) is provided following the draw rollers 6 or 10, and enables the draw textured yarn from the draw rolls to be additionally heat-treated at a temperature of 160 to 250C. while allowing a shrinkage of not more than 50% or while maintaining it at constant length. Thus, the control of the degree of crimping and the improvement of dimensional stability against heat are possible.

The textured yarns produced by the method of this invention are almost free from fluffs, loops and tight spots, and have superior crimp characteristics and mechanical properties and also good level-dyeability. These textured yarns have the advantage that the amount of dye exhaustion does not change even when the temperature of the heat-treating heater fluctuates between 160 and 210C.

FIG. 5 is a graphic representation showing the relation between the degree of dye exhaustion and the tem perature of the heat-treating heater with respect to the texture yarn obtained in the present invention and an ordinary texture yarn. Curve A in this FIG. refers to the textured yarn obtained in this invention, and curve B, to the conventional texture yarn. As is clear from this Figure, with the texture yarn (A) in accordance with this invention, there is scarcely any change in the degree of dye exhaustion when the temperature of the heat-treating heater is within the range of 160 to 210C. However, with the conventional texture yarn (B), the degree of dye exhaustion changes with the temperatures of the heat-treating heater. Thus, even a slight flurctuation in the temperature of the heater results in dyeing uneveness.

The degree of dye exhaustion denotes the grade of the depth of color observed by the naked eye with a textured yarn which has been dyed by dipping it for minutes in a boiling dye bath containing 2% of Eastman Polyester Blue GLF (CI DISPERSE BLUE 27). Larger numerical values show deeper color.

In the performance of the present invention, various auxiliary means can be employed at the time of initiating the operation or at the time of continuous operation.

Examples of the auxiliary means at the time of initiating the operation are:

1. A method wherein without bringing the yarn into contact with the heat-treating heater, the operation is started using a twist multiplier 50 to 85% of that in normal operation, and then the yarn is brought into contact with the heat-treating heater.

2. A method wherein the operation is started at a draw texturing speed expressed by the equation.

wherein V is the draw texturing speed, and yarn stringing is performed, and then the draw texturing speed is raised to a predetermined value.

3. A method wherein at the time of initiating the operation, yarn stringing is performed while the undrawn yarn is maintained so as not to come close to the surface of the heat-treating heater, and then the draw texturing of the yarn is started while passing the yarn throughia zone near the surface of the heat-treating heater which zone is held at 50 to C, and then the yarn is {brought into contact with the heat-treating heater.

If such auxiliary means are applied, the breakage of yarn at the time of initiating the draw texturing process and at the time of contacting the yarn with the heattreating heater can be substantially prevented, and therefore, the efficiency of the yarn stringing operation and the working efficiency of the draw texturing apparatus are drastically increased.

Examples of the auxiliary means at the time of con tinuous operation are:

1. A method wherein the end of the undrawn yarn on the package and the forward end of the undrawn yarn on the package are cold drawn and tied before the package of the undrawn yarn being processed becomes are arranged in a plurality of rows, and the transfer of the yarn is performed between two packages facing each other on the vehicles.

If such auxiliary means are applied, it is possible to perform the draw texturing process of this invention continuously.

The following Examples illustrate the present invention.

The measurement values in the Examples were obtained by the following methods.

1. Loops and Fluffs The number of fluffs and loops appearing on both end surfaces of 2.5 Kg of a square end cheese (wind-up width 150 m).

2. Tight spot The number of untwisted portions (portions remaining alternately twisted in the yarn without detwisting as a result of heat-fusing of filaments to each other) per 10 m of the processed yarn.

3. Degree of total crimp (TC) An initial load (2 mg/d) and a heavy load (0.2 g/d) were exerted at the same time on a processed yarn of a constant length, and after a lapse of 1 minute, the length of the sample yarn was measured and designated I Then, only the heavy load was removed, and the yarn was boiled in boiling water for minutes and allowed to dry spontaneously for 24 hours in a free condition. Then, the initial load and the heavy load were exerted on the yarn at the same time, and after a lapse of 1 minute, the length of the sample yarn was measured, and made I Then, after removing only the heavy load, and after a lapse of 1 minute, the length of the sample was measured and made 1 TC is expressed by the following equation.

4. Dyeing uneveness 5. Crimp fastness A load was exerted on a polyester textured yarn, and the yarn was continuously stretched, and the elongation of the yarn at disappearance of the 'crimps and its elongation at break were measured. The crimp fastness was calculated by the following equation.

Elongation at the disappearance of crimps Elongation at break X 100 (in Crimp fastness 6. Moisture content About 20 g of the undrawn yarn located 5 mm outwardly of the surface of the undrawn yarn bobbin and at the central part with respect to the axial direction of the bobbin (that is, the undrawn yarn present in the innermost layer of the package which is not al all exposed to the outer atmosphere) was quickly sampled. The resulting sample was completely dried, and placed in a bottle of a known weight (W g), and the bottle was sealed with a lid. The bottle was then precisely weighed, and the weight was W The lid was removed, and the bottle was placed in a hot air dried held at a temperature of i 2C. After drying for 3 hours, the bottle was sealed with the lid and again precisely weighed. The weight was W g. The moisture content (70) was calculated as follows:

7. Different in dye exhaustion A standard sample was a texture yarn which was obtained by subjecting an as-spun undrawn yarn to draw texturing within 8 hours. The standard sample and a sample to be measured were knitted side by side, and the knitted fabric obtained was dyed in the same was as the dye exhaustion degree test mentioned above. The difference in dye exhaustion between the measuring sample and the standard sample was evaluated on the resulting dyeings by the naked eye on the scale shown below. The dye exhaustion difference shows an average value of the dye exhaustion difference for 10 samples of the same level.

0: Not discriminatable +0.5: Slight difference +1.0: Difference fully observed +1.5: When the yarn having a dye exhaustion difference of 1.0 was assumed to be a standard sample, there is a slight difference +2.0: A slight difference observed in the same way as above using a yarn having a dye exhaustion difference of 1.5

The plus symbol means that the sample was dyed deeper than the standard sample, and the minus symbol shows that it was dyed in lighter color than the standard sample.

EXAMPLE 1 Temperature of the heat-treating heater C Rotating speed of spindle 30.1 X 10 rpm Twist multiplier 1.0 Draw ratio (DR) 3.14 to 1.30

Draw texturing speed 75.8 to 1 15.5 m/min.

The results are shown in Table 1 below.

Table 1 Run Undrawn Draw Yarn Loops and Tight TC Dyeing Overall DR texturing stringing fluffs spots unevenness evaluation No. An speed per 25 kg per 10 in W!) (m/min) M 00060 3.14 75.8 Frequent 23 3 5 32.6 .5 Poor yarn break 1-2 0.0106 2.78 80.0 Good 2 0 1 34.3 4.5 Good l-3 0.0184 2.30 88.5 0 0 33.7 4.5 Excellent 1-4 0.0278 2.00 94.9 0 0 35.1 4.5 l- 0.0387 1.70 102.9 0 0 32.5 4.5 l-o 0.0485 1.50 109.6 0 0 34.1 4.5 1-7 0.0552 1.35 115.5 0- 3 0 32.3 3.0 Fair EXAMPLE 2 EXAMPLE 4 An undrawn polyethylene terephthalate yarn (30 2 denier/48 fil) having a birefringence of 0.0226 was subjected to draw texturing using an apparatus shown in FIG. 1, under the following conditions.

Temperature of the heat- An undrawn yarn (240 denier/24 filaments) of polyethylene terephthalate having an intrinsic viscosity of 0.0152 and a birefringence of 0.62 (containing 5 mol "/0 of isophthalate) was subjected to draw texturing under the following conditions.

treating heater 180C. Rotating speed of the spindle 30.1 X 10 r/m Temperature f th hem. multiplier treating heater 175C. DR L8 to 4 Rotating speed of the spindle 40.2 X 10" rpm Draw texturmg speed 1 14 to 9) m/nun. Twist multiplier 9 DR 2.4 The results are shown in Table 2 below.

Table 2 Run DR Yarn Loops and Tight 'lenacity Elongation TC Dyeing Overall stringlul'fs spots unevenness evaluation No. ing per 10 m (g/d) (71) d Frequent 2 1 1.8 yarn 4 8 3.17 29.2 34.7 .5 Poor break 1 2-2 1.9 Good 1 l 3.68 26.8 33.0 4.0 Good 2-3 2.0 0 0 3.72 25.3 32.8 4.5 Excellent 2-5 2.2 l 0 3.65 20.1 31.9 4.0 Good 2-(\ 2.3 l5 0 3.24 18.5 30.4 3.5 Poor EXAMPLE 3 A polyethylene terephthalate undrawn yarn (366 denier/ filaments) having a birefringence of 0.01 78 was subjected to draw texturing under the conditions shown in Table 3, using two types of apparatus. The physical properties of the resulting texture yarns were compared. The results are shown in Table 1.

Table 3 Run No. 3.1 3.2

Apparatus used Figure 1 Draw pin provided between feed rollers and a hot plate Processing conditions Temperature of the drawn pin 90C. Temperature of the hot plate of the heat-treating heater (C.) 200 210 Rotating speed (rpm) of the spindle 41.5 X 10" 41.5 X 10" Twist multiplier 0.98 0.98 DR 238 2.6 Draw tcxturing speed (m/min.) 161.6 1545 Physical properties of the yarn Loops and fluffs per 2.5 kg 0 to 3 5 to 15 TC (71) 34 30 Torque (T/25 cm) 20 42 Knittability Good With some problem Lil I (to The resulting texture yarn was free from fluffs. loops, and tight spots, andex-hibited good crimpability with a TC of 32.5 When this yarn was dyed in blue color, the color was brilliant, and the yarn had good feel.

EXAMPLE 5 Three polyester undrawn yarns (A, B and C) shown in Table 4 were each subjected to draw texturing under the conditions shown in Table 4 and varying the bended angles of the yarn using an apparatus as shown in FIG. 4 which included 1 to 3 guides between the false twisting spindle and draw rollers. The angle of pulling out the yarn from the spindle was adjusted to 20 in all cases. The results are shown in Table 5. In Table 5, Runs Nos. 7, 8. 9, 12, 13 and 14 are examples of the present invention and the others are for comparative purposes.

" l l l 2 Table 5 Run Num- Undruwn yarn A B C her No. of Bending angle guides *4 *4 *4 Tight Loops and Tight Loops and Tight Loops and a, a: 01;, 2a spots fluffs spots fluffs spots fluffs *1 5-3 1 24 24 1 l 5 9 0 25 0 5-4 35 35 4 3 l2 3 5-5 45 45 5 40 10 31% 6 41 5-6 8.5 9.0 17.5 24 5 6 0 l4 0 5-7 3 27 2 0 2 0 2 0 *2 5-8 2 25 47 72 1 1 0 I 0 1 5-9 52 78.5 I30.5 0 I 0 l (J 0 5-10 145 145 290 2 25 0 I8 I 10 5-11 5.5 '4 15 24.5 3 0 l3 0 I8 0 5-12 5 5.5 25.7 36.2 0 0 0 0 0 (l Note: '1: Using only guide 8 shown in FIG. 4. *2: Using guides 8 and ii shown in FIG. 4. 3: Using guides 8. 8' und 8" shown in FIG. 4. '4: The bended angle shown in FIG. 4.

EXAMPLE 6 25 EXAMPLE 7 An undrawn yarn (345 denier/30 fil, brirefringence 0.013) of polyethylene terephthalate having an intrinsic viscosity of 0.632 as measured in o-chlorophenol at C. was subjected to draw texturing using the apparatus of FIG. 1 under the conditions shown in Table 6.

Example 6 was repeated except that the surface temperature of the feed rollers was adjusted to 90C. and the time of contact between the undrawn yarn and the feed rollers was varied. The results are shown in Table Table 7 Run Contact time Tenacity Elon ution- TC Fluffs Tight spots Dyeing No. (seconds) (g/d) r) (7:) unevenness The yarn obtained was heat-treated at 200C. while al- EXAMPLE 8 lowing shrinkage of 14.8 and then wound up. The results are shown in-Tab1e 6.

Temperature of the surface Polyethylene terephthalate chips having an intrinsic viscosity of 0.645 were spun at 291C. and taken up at 5 a rate of 2,000 m/min. to form an undrawn yarn (355 denier/30 fill having birefringence of 0.0145. In this Ofthe feed rollers to spinning process. an oil of the following formulation Time of contact of the undrawn n k yarn with the feed rollers 0.06 second was pp to the y y an mg er to an plc TemPemure a up of 1 The undrawn yarn was wound up, and a1- 61 9 8 50 lowed to stand for 3 months in an atmosphere held at Draw ratio 2.452 40C., and then subjected to draw texturing under the Draw texturing speed 185 m/min. f ll i diti Table 6 Run Temperature of Tenacity Elongation T. C. Fluffs Tight spbts Dyeing No feed rollers per 10 m unevenness (C) (g/d) ('70) Formulation of Oil A Mineral oil Ethylene oxide-added olcyl alcohol Octyl phosphonic acid amine Oleic acid triethanolamine Draw texturing conditions Draw ratio Temperature of the heattreating heater Number of twists Processing speed 80 "/1 by weight 10 71 by weight 40 7: by weight 6 '7: by weight 2600 T/M 200 m/min.

The results are shown in Table 8.

EXAMPLE 10 This undrawn yarn as wound on a package was placed in an aging chamber, and aged under the conditions shown in Table 10.

the false twisting spindle and the total sum 1, a of the yarn bended angles were changed. The results are shown in Table 9.

Table 8 Run State of oil Moisture content Moisture content Dye exhaustion Dyeing immediately (71-) after difference unevenness No. after spinning allowing to stand for 3 (7r) months at 40C.

8-1 10 7: aqueous 3.5 2.5 +4 2.0

emulsion 8-2 6 7: aqueous 1.4 1.1 2 2.5

emulsion 8-3 aqueous 0.8 0.7 +0.3 4.5

emulsion 8-4 Straight oil 0 0.2 0.3 4.5 8-5 2-stage oiling 0.5 0.5 +0.5 4.5

.* Z-stage oiling: first stage 1 aqueous solution of sodium dioctyl sulfosuccinate .second stage =straight oil EXAMPLE 9 Table 10 Polyethylene terephthalate having an intrinsic viscos- I ity of 0.645 as measured in o-chlorophenol at C. li fl jg gf g Agmgtme was spun at 292C. and taken up at a speed of 1,7800 35 in the aging (hours) m/min. to form an undrawn yarn having a 1,800 of Chamber 0.0135 and a denier of 360 denier per 30 filaments. 4 10 24 The undrawn yarn was subjected to draw texturing :8; 5g 2; using an apparatus of the type shown in FIG. 1 except 104 5 that the false-twisting spindle and the draw rollers were lg-g g2 22 replaced by those shown in FIG. 4, and a second heat- 26 3 treating heater was equipped, under the following con- 10-8 26 600 ditions. At this time, the time during which the yarn ran between the outlet of the first heat-treating heater and 45 After aging, the undrawn yarn package was transported to a drawing and false-twisting factory remote from the spinning factory. The time which elapsed from the end of aging to the initiation of drawing and false- ?g f twisting was about 20 hours, and the temperature durfirst eat-treating 210C. ing transportation was 24 to 29C.

eater Temperature of the The drawing and false-twisting was performed under second heat-treating 205C. t heater the following conditions in a chamber maintained at a Number of twists 2590 temperature of 27C i 2C and a relative humidity of Draw texturing speed 200 m/min. i 5

Table 9 Run Time of Yarn Tenacity Elongation Degree of Crimp Tight spots Fluffs yarn bended crimps fastness per 20 in No travel angle (seconds) (a,+a (g/d) 4. The process of claim 1 wherein the undrawn yarn Draw p is one whose moisture content is maintained always at t e 195cc not more 1.0 7: by weight from the end of spinning (hm p at d to the 1n1t1at1on of draw texturmg.

1 meters/min 5. The process of claim I wherein the undrawn yarn lltlumhcr of fill thwists 2590 TM is brought into contact with the surfaces of feed rollers t re 1) t 'ggg fi l c 205C heated at 60 120C. for at least 0.05 second. I il 1h d 6. The process of claim 1 wherein the heat-treating hez i lgr on e beam 14,87. 10 heater is heated to from 160 to 210C.

. 7. The process of claim 1 wherein the process is car- T p p of the resultmg Polyester textured ried out while maintaining a twist multiplier expressed yarns are shown in Table 1 1. by the f ll i equation Table 11 Run Tenacity Elongation Dyeing Dyeing Fluffs Tight Procesdifference unevenness spots sability No. (g/d) (70) (grade) (71) per in (times) The dyeing difference shown in the above table was a: F \/De measured in accordance with the following method. 32500 A standard sample was prepared by processing an undrawn yarn immediately after arrival at the factory. An 30 W i s g g of false A E S l s De undrawn yarn in the same lot as the sample was proo t g li" 'h to cessed 5 days after arrival at the factory to form a meaf li f f l a 3 t e PIPCCSS g suring sample. The standard sample and the measuring 6 l 7 t e texturmg Spec at sample were knitted side by side to form a sample. The 9 f m f l 2 h h resulting sample was dyed by dipping in a dye bath cone PYPCeSS w erem t f process formed wh1le mamtammg the draw ratio at 2.2 to 2.8. taming 2 based on the weight of the sample, of C1 10 Th recess of claim 1 wherein the am i bent DISPERSE BLUE 27 at 100C. for 60 minutes with the r e P Y S b t d t 1 100 f l by at least 2 yarn guldes prov1ded between the false goods'to'hcluor. ram? emg mam alnea o twister and the draw rollers and the total sum of the lowed by washing w1th water and drying. After drying, b m 168 is adusted to a 30 t 2700 the degree of the difference in dye exhaustion between 40 1 i 1 f CM 10 h th the standard sample and the measuring sample was u z i w g i e 2 2 1 1 evaluated by the naked eye on the same scale as def n s g zg 91 g g 8 3 ea scribed before the Examples. l P ea er an WIS er or o wh 0nd in an at room temperature.

at we claim 1s.

12. The process of claim 1 wherem the undrawn yarn A P for prodllcmg a polyester textured y is made to run from the inlet of the heat-treating heater which comprises drawlng and slmultaneously falseto a point 1 mm apart from it while being preheated at Pwlsting undrawn p y Y g} draw textuf- 60 to 150C. without contacting with the heated surlng apparatus equlpped w1th a heat-treatmg heater and face of the heater, and then the yarn is brought into a false twister between feed rollers and draw rollers, Contact i h h h d surface f the heater, 1 above wherein the undrawn polyester yarn has a birefringence being defined by the following equations (A n) of 0.01 to 0.05, and the draw ratio (DR) is adjusted to a value expressed by the following equations I 5 according to the birefringence of the undrawn polyesand ter yarn 0.03x 0.2y l5l 0.3x 2y 100 g l'l376 5 DR S l 789 log wherein x is the denier of the undrawn yarn and y is the d speed of feeding the undrawn yarn (m/min.). 5 2 8 13. The process of claim 7 wherein the operation is 2 Th f l l h th d started with a false twist multiplier 50 85 of that in h F O 832'; e fawn yarn normal operation without bringing the yarn into f rmgencef 1 h d contact with the heat-treating heater, and then the yarn 6 Process 0 6 am w eremt e um yam is brought into contact with the heat-treating heater one has been f under the temperature and the false twist multiplier is increased to apredeter- (TC)-t1me (t hours) condmons expressed by the folmined value lowing equations 14 Th e process of clalm 8 wherem yarn stringmg 1s O'0486T) I 5 -21 6424 performed by initiating the operation at a draw textur- (where 20C 5 T S 30C.)

10(2.6040.0486T) g I 10(3.2590.0526T) (where 30C 5 T i 40C.).

ing speed expressed by the equation wherein V is the draw texturing speed, and De is the denier of the undrawn yarn, and then the draw texturing speed is increased to a predetermined value.

15. The process of claim 1 wherein at the time of initiating the operation, the yarn is strung up by keeping the undrawn yarn from the surface of the heat-treating heater so that it does not come close to it, and then draw texturing of the yarn is started while passing the yarn through a zone maintained at a temperature of 50C. to 130C. near the surface of the heat-treating heater, and thereafter, the yarn is brought into contact with the surface of the heat-treating heater.

Claims

1. A process for producing a polyester textured yarn which comprises drawing and simultaneously false-twisting an undrawn polyester yarn using a draw texturing apparatus equipped with a hEat-treating heater and a false twister between feed rollers and draw rollers, wherein the undrawn polyester yarn has a birefringence ( Delta n) of 0.01 to 0.05, and the draw ratio (DR) is adjusted to a value expressed by the following equations according to the birefringence of the undrawn polyester yarn -1.8349 log Delta n - 1.1376 < or = DR < or = -2.1789 log Delta n - 1.3509 and DR < or = 2.8.

1. A PROCESS FOR PRODUCING A POLYESTER TEXTURED YARN WHICH COMPRISES DRAWING AND SIMULTANEOUSLY FASTE-TWISTING AN UNDRAW POLYESTER YARN USING A DRAW TEXTURING APPARATUS EQUIPPED WITH A HEAT-TREATING HEATER AND A FALSE TWISTER BETWEEN FEED ROLLERS AND DRAW ROLLERS, WHEREIN THE UNDRAWN POLYESTER YARN HAS A BIREFRINGENCE ($N) OF 0.01 TO 0.05, AND THE DRAW RATIO (DR) IS ADJUSTED TO A VALUE EXPRESSED BY THE FOLLOWING EQUATIONS ACCORDING TO THE BIREFRINGENCE OF THE UNDRAWN POLYESTER YARN

1.8349 LOG $N - 1.1376 $ DR $ -2.1789 LOG $N 1.3509

2. The process of claim 1 wherein the undrawn yarn has a birefringence of 0.01 to 0.025.

3. The process of claim 1 wherein the undrawn yarn is one which has been aged under the temperature (T* C)-time (t hours) conditions expressed by the following equations 10(2.604 - 0.0486T) < or = t < or = -211.2T + 6424 (where 20*C < or = T < or = 30*C.) or 10(2.604 - 0.0486T) < or = t < or = 10(3.259 - 0.0526T) (where 30*C < or = T < or = 40*C.).

4. The process of claim 1 wherein the undrawn yarn is one whose moisture content is maintained always at not more than 1.0 % by weight from the end of spinning to the initiation of draw texturing.

5. The process of claim 1 wherein the undrawn yarn is brought into contact with the surfaces of feed rollers heated at 60* -120*C. for at least 0.05 second.

6. The process of claim 1 wherein the heat-treating heater is heated to from 160* to 210*C.

7. The process of claim 1 wherein the process is carried out while maintaining a twist multiplier expressed by the following equation

8. The process of claim 1 wherein the process is performed while maintaining the draw texturing speed at 75 to 600 m/min.

9. The process of claim 2 wherein the process is performed while maintaining the draw ratio at 2.2 to 2.8.

10. The process of claim 1 wherein the yarn is bent by at least 2 yarn guides provided between the false twister and the draw rollers, and the total sum of the bent angles is adjusted to from 30* to 270*.

11. The process of claim 10 wherein the process is controlled so that the yarn runs between the heat-treating heater and the false twister for 0.13 to 0.3 second in air at room temperature.

12. The process of claim 1 wherein the undrawn yarn is made to run from the inlet of the heat-treating heater to a point l mm apart from it while being preheated at 60* to 150*C. without contacting with the heated surface of the heater, and then the yarn is brought into contact with the heated surface of the heater, l above being defined by the following equations l > or = 5 and 0.03x + 0.2y - 15l < or = 0.3x + 2y + 100 wherein x is the denier of the undrawn yarn and y is the speed of feeding the undrawn yarn (m/min.).

13. The process of claim 7 wherein the operation is started with a false twist multiplier 50 - 85 % of that in normal operation without bringing the yarn into contact with the heat-treating heater, and then the yarn is brought into contact with the heat-treating heater and the false twist multiplier is increased to a predetermined value.

14. The process of claim 8 wherein yarn stringing is performed by initiating the operation at a draw texturing speed expressed by the equation

15. The process of claim 1 wherein at the time of initiating the operation, the yarn is strung up by keeping the undrawn yarn from the surface of the heat-treating heater so that it does not come close to it, and then draw texturing of the yarn is started while passing the yarn through a zone maintained at a temperature of 50*C. to 130*C. near the surface of the heat-treating heater, and thereafter, the yarn is brought into contact with the surface of the heat-treating heater.

16. The process of claim 1 wherein before an undrawn yarn package being processed becomes empty, the end of the undrawn yarn on the package is tied with the forward end of an undrawn yarn on an undrawn yarn package to be processed subsequently, after cold drawing each end of the undrawn yarns.