US3698178A

US3698178A - Method of manufacturing textured yarn having trasverse deformities

Info

Publication number: US3698178A
Application number: US59065A
Authority: US
Inventors: Mutsuo Iwaoka; Akio Takegawa; Hiraku Inoue; Katsusuke Egami; Kouiti Nishikura; Shigeji Yamashita; Tadahiro Nagayasu
Original assignee: Toray Industries Inc
Current assignee: Toray Industries Inc
Priority date: 1969-08-27
Filing date: 1970-07-29
Publication date: 1972-10-17
Anticipated expiration: 1989-10-17
Also published as: GB1320583A; CH537471A; FR2059225A5; DE2042591A1; CA921344A

Abstract

A method of manufacturing textured yarn comprises providing a crimped yarn composed of numerous crimped and entangled together thermoplastic synthetic fibers, partially removing some of the crimp from the crimped yarn, heating and pressing together the resulting partially crimped yarn to contact the fibers at their mutually intercrossed locations with sufficient pressure and at a sufficient temperature to effect permanent transverse deformation of the fibers at their contact points, and terminating the heating and pressing to obtain a textured yarn composed of numerous fibers having longitudinally and randomly spaced transverse deformities. The yarn is initially crimped by false twisting and steam setting, and some of the crimp is removed from the crimped yarn to remove from 75 to 95 percent of the crimp.

Description

United States Patent Iwaoka et al. a

[ METHOD OF MANUFACTURING TEXTURED YARN HAVING TRASVERSE 'DEFORMITIES [72] Inventors: Mutsuo lwaoka, Yasu-gun; Akio Takegawa, Kusatsu; Hiraku lnoue; Katsusuke Egami, both of Otsu; Kouiti Nishikura, Kusatsu; Shigeji Yamashita, Koga-gun; Tadahiro Nagayasu, Otsu, all of Japan [73] Assignee: Toray Industries, Inc., Tokyo, Japan [22] Filed: July 29,1970

211 App]. 196.: 59,065 v [30] Foreign Application Priority Data Aug. 25, 1969 Japan ..44/67299 Feb. 2, 1970 Japan ..45/8596l [52] US. Cl. .;..57/l57 TS, 28/72.11 [51] Int. Cl. ..D02h l/02, D02h 1/20 [58] Field of Search ...57/34 R, 34 HS, 34 B, 157 TS, 57/157 MS; 28/72 HR, 72.11; 264/168 [56] References Cited UNITED STATES PATENTS 2,202,031 5/1940 Smith ..57/34 X 3,129,485 4/1904 Shattuck ..57/34 X [151 3,698,178 [4 1 Oct. 17,1972

3, 37,119 6/1964 Crouzet ..57/34 x 3,221,385 12/1965 Stanley ..5?/34 x 3,431,716 3/1969 Mertens ..s7/157 x FOREIGN PATENTS 0R APPLICATIONS 884,492 12/1961 Great Britain ..57/34 Primary Examiner-Werner l-l. Schroeder Attorney-Robert E. Burns and Emmanuel J. Lobato 5 7] ABSTRACT A method of manufacturing textured yarn comprises providing a crimped yarn composed of numerous crimped and entangled together thermoplastic synthetic fibers, partially removing some of the crimp from the crimped yarn, heating and pressing together the resulting partially crimped yarn to contact the fibers at their mutually intercrossed locations with sufficient pressure and at a sufficient temperature to effect permanent transverse deformation of the fibers at their contact points, and terminating the heating and pressing to obtain a textured yarn composed of numerous fibers having longitudinally and randomly spaced transverse deformities. The yarn is initially crimped by false twisting and steam setting, and some of the crimp is removed from the crimped yarn to remove from 75 to 95 percent of the crimp.

10 Claims, 24 Drawing Figures PA'TENTEDBCI 17 m2 SHEET UIUF 11 PATENTEDum 11 m2 SHEET 02 0F 11 WENTEDHET 17 I972 WET 03oF 11 FIG.5B-

FIG. 68

FIG. 6A

W Y m/ PATENTEBncr 11 m2 SHEET URUF 11 FIG.6C

PIITENTEDncI 17 I972 SHEET 06 0F 11 w E H b -mT d N O C .%WW 8 mm 9 w I S S .9 g 9 w IIIIETP F N F ET TIM n WMH m m w w M w X5; zomzmc @EEQ M259 to Emtm HEAT PRESSING TEMPERATURE ADDITIONAL TO STEAM HEATING TEMPERATURE IN C PATENTEDnnT 11 I972 SHEET 07UF II E5 E0 EXTENT OF STRETCH IN THE HEAT PRESSING IN ZOTZN j FZmFOi Q3: 10 PZmummE lb 2030405060 7080 HEAT PRESSING TEMPERATURE ADDITIONAL TO STEAM HEATING TEMPERATURE IN "C A E 5 E E 8R wmmzg im mo mmmowa PATENTEBncT 1'! I972 SHEET UBIIF I1 I 3 0 5 0 7D HEAT PRESSING TEMPERATURE ADDITIONAL TO STEAM HEATING TEMPERATURE IN C 3 m 2 m w Q1 wmwzifim E0 HERE I0 20 3'0 4'0 5'0 6'0 7'0 8'0 HEAT PRESSING TEMPERATURE ADDITIONAL TO STEAM HEATING TEMPERATURE IN C 3.698.178 SHEET near 11 PATENTEnnm 1 7 m2 Q EQ Z mmmZEv Dm nEO mmmwma EXTENT OF STRETCH IN THE HEAT PRESSING xwoE/z ZO mZm SE nESEEQ Qm 2E mmwZUjDm I EO mmmoma w m w 5 .9 E E E E E E E E E XmoZE ZOEmZMESEEQ mSEEQ fofzMTsfs HEATFRESSING PRESSURE IN /d PATENTED 0B1 11 I972 SHEET llBF 11 METHOD OF MANUFACTURING TEXTURED YARN HAVING TRASVERSE DEFORMITIES The present invention relates to an improved method of manufacturing textured yarn, more particularly relates to method of manufacturing a textured yarn of substantially crimpable nature composed of fibers having numerous transverse cross sectionally deformed portions distributed at random along the of the yarn.

The terms used in the ensuing description are defined as follows. Percent Crimp Elongation A specimen textured yarn is left for longer than 24 hours at a temperature of about 20 C and a relative humidity of about 65 percent and subsequently, is treated within a boiling water bath for about 20 min. After drying, the yarn of 20 cm free length is subjected to a loading of 2 mg/denier for 30 sec. and the length (L,,) thereof is recorded. Further, the yarn is subjected to a loading of 100 mg/denier for 30 sec. and the length (L,) is recorded, also. The resulting percent crimp elongation is given by;

Percent Crimp Potentialization Provided that the measurement applied to the calculation of the percent crimp elongation is performed as to the specimen yarn in the condition before treatment with the boiling water, percent crimp elongation before the boiling water treatment is designated as A and that after the treatment is designated as B. The resulting percent crimp potentialization is given by;

Crimp Dimension Index A componental fiber is extracted from a given crimped yarn for measurement of the length (L) under a load of 2 mg/denier and the number of crimps (N) within that length in that loaded condition. The apparent size of the amplitude of the crimp (U) is also measured in this loaded condition. The specimen fiber is further subjected to a loading of 0.1 g/denier and the length (L) thereof is recorded. The resulting crimp dimension index is then given by; I

With recent expansion of the consumers preference for the textile product of modified and diversified quality, the technique of providing the material yarn with crimps has been developed. Through the use of the crimped yarns, the resulting textile products can be accompanied with a diversified apparent aesthetic effect, bulky touch, wearing comfort and excellent warmness retainability. In this connection, however, when considered from the point of view of the manufacturing process, provision of crimps to the material yarn in the earlier stages of the production process requires a temporary extinction of the once developed crimps in the later stage of the process and thusly extinct crimps have tobe re-developed in the end products. Without employing such temporary extinction of the crimps, the material yarns cannot be smoothly processed in the manufacturing process. For example, when the once crimped yarns are to be processed through weaving, the yarns have to be sized or strongly twisted prior to the weaving in order to obviate malfunctions caused by an effective potentialization of the crimps is strongly desired.

Further, in order to meet the consumers requirement for the diversified quality of the product, a technique of deforming the transverse cross-sectional profile of the fibers composing the yarn is developed, also. This locational deformation of the transverse cross-sectional profile of the fibers is known to affect the buckling strength of the yarns in the end product, especially when the end product is used for mattings such as carpets. In the conventional manner of effecting this deformation, yarns stretched to the maximum crimp elongation are subjected to an intermittent pressing by, for example, press rollers and the componental fibers are transversely deformed at the pressed portions. This pressing is in most cases performed in an intermittent and periodical mode. So, the resulting componental fibers in the yarn are naturally provided with transversely deformed portions distributed periodically along the length thereof. Thusly resulted periodicaly disposition of the deformed portions lessen the diversfying effect on the quality of the yarn and cannot perfectly conform to the requirement by the consumers.

Therefore a principal object of the present invention is to provide a method of manufacturing textured yarn capable of providing the end products made thereof with natural fiber-like diversified functional and aesthetic qualities.

Another object of the present invention is to provide a method of manufacturing textured yarn which has an enhanced durability against buckling load to the end product made thereof.

Still another object of the present invention is to pro vide a method for manufacturing the textured yarn of above-described nature in a continuous process with considerable increase in the production efficiency.

A further object of the present invention is to provide a method for effectively potentializing the crimps imparted to the yarn without employing such additional works as sizing or high twisting, thereby reducing the manufacturing cost of the textile products made up of crimped textured yarns.

In order to satisfy the above-recited objects, the textured yarn of the present invention is composed of thermoplastic synthetic fibers of substantially potentially crimpable nature and having numerous transverse cross-sectionally deformed portions distributed at random along the length thereof. In the manufacturing of the yarn, after false twisting with pressured steam setting, the false twisted yarn is subjected to a dry heat pressing at a stretch smaller than the maximum crimp elongation thereof.

In the dry heat pressing, because the once crimped yarn is imperfectly stretched, fibers in the yarn configuration is retained in an imperfectly straightened condition and are at locations crossingly superimposed to each other at random. By the application of the heat pressing, the fibers are mutually put in a pressure contact especially at locations crossingly superimposed to each other. Resultingly, the crossing superimposed portions are deformed plastically. Because the fibers are crossingly superimposed at random portions in the configuration of the yarn, the deformed portions are formed at random' along the length of the fibers, also. Further, because the yarn is heat pressed in an appreciably stretched condition, the crimps developed during the false twisting can be simultaneously and substantially potentialized.

Further features and advantages of the present invention will be made more apparent from the ensuing description, reference being made to the accompanying drawings, wherein:

FIG. I is a diagrammatic representation of a principal embodiment of the arrangement for carrying out the method of the present invention,

FIG. 2 is a diagrammatic representation of the crimped yarn internal configuration in an unstretched condition,

FIG. 3 is a diagrammatic representation of the yarn shown in FIG. 2 under a limited stretch,

FIG. 4 is a diagrammatic representation of the yarn shown in FIG. 2 under the maximum crimp elongation,

FIG. 5A is a fragmentary perspective view of the fibers transverse cross-sectionally deformed according to the method of the present invention,

FIG. 5B is a photographic representation of the actual fibers obtained according to the present invention,

FIGS. 6A and 6B are an example of the microscopic representation of transverse cross-sectional profiles of the yarn before and after the heat pressing of the present invention, respectively,

FIG. 6C is a photomicroscopic representation of the yarn cross section shown in FIG. 68,

FIGS. 7A and 7B are another example of the microscopic representation of transverse cross-sectional profiles of the yarn before and after the heat pressing of the present invention, respectively,

FIG. 7C isa photomicroscopic representation of the yarn cross section shown in FIG. 78,

FIG. 8 is a graphical representation of the relationship between extent of torque residual in the yarn and extent of stretch in the heat pressing for a nylon yarn processed through the heat pressing of the present invention,

FIG. 9 is a graphical representation of the relationship between crimp dimension index and the heat pressing temperature for a nylon yarn processed through the heat pressing of the present invention,

FIG. 10 is a graphical representation of the relationship between percent crimp potentialization and extent of stretch derived from the results shown in FIGS. 8 and 9,

FIG. 11 is a graphical representation of the relationship between degree of bulkiness and heat pressing temperature for the yarn used in the experiment of FIG. 9,

FIG. 12 is a graphical representation of the relationship between crimp dimension index and heat pressing temperature for a polyester yarn processed through the heat pressing of the present invention,

FIG. 13 is a graphical representation of the relationship between degree of bulkiness and heat pressing temperature for the polyester yarn of FIG. 12,

FIG. 14 is a graphical representation of the relationship between crimp dimension index and extent of stretch for an acrylic yarn processed through the heat pressing of the present invention,

FIG. 15 is a graphical representation of the relationship between crimp dimension index and heat pressing pressure for the nylon yarn of FIG. 9,

FIG. 16 is a graphical representation of the relationship between crimp dimension index and heat pressing pressure for the polyester yarn of FIG. 12,

FIG. 17 is a schematic side view of an embodiment of the heat pressing assembly modified from the one shown in FIG. 1,

FIG. 18 is a perspective view of another embodiment of the heat pressing assembly modified from the one shown in FIG. 1,

FIG. 19 is a schematic side view of an arrangement to be attached to the one shown in FIG. 1 for an additional crimp potentialization effect.

Referring to FIG. 1, there is shown a principal arrangement for carrying out the method of the present invention in a rough illustration. A non-crimped material yarn 1a composed of thermoplastic synthetic fibers is drawn out from a supply package 2 and advanced to a steam heater 7 via a pig-tail guide 3, a feed roller assembly 4 and a guide roller 6 located upstream of the steam heater 7. The steam heater 7 is provided with a circulation of saturated steam under pressure and the yarn la is wet heated during passing through the steam heater 7. Next, thusly heated yarn 1a is subjected to a false twisting operation by a false twist spindle assembly 8 and is taken up from the false twisting zone by the first take-up roller 11 via guide rollers 9 in the form of a crimped yarn 1b. In succession, the crimped yarn lb is processed to a dry heat pressing operation by a heat pressing assembly 12, which assembly includes, in the shown example, a heated drum 13 and a pair of

press rollers

14a and 14b in a peripheral pressure contact with the peripheral surface of the heated drum 13. After this dry heat pressing operation, the crimp poten? tialized yarn 1c is taken up onto a package 17 by a winding-up drum 16 via the second take-up rollers 15. The operations from the supply package 2 to the false twisting by the false twist spindle assembly 8 are performed in known manners.

The relationship between the surface speeds of the 1st take-up roller 11, the heated drum l3 and the second take-up roller 15 is so selected as to stretch the crimped yarn 1b to an extent smaller than the maximum crimp elongation of the crimped yarn 1b. Owing to thusly limited stretch, the individual fibers in the crimped yarn 1b is subjected to the dry heat pressing in a disposition shown in FIG. 2, in which disposition the individual fibers still retain to some extent a crimped condition. It should be noted that the individual fibers in the yarn 1b are subjected to the heat pressing operation while retaining their crimped condition to some extent. This is the very important and characteristic feature of the art of the present invention. During the heat pressing operation, the fibers are pressed in a direction substantially perpendicular to their longitution in the configuration of the yarnbecause the yarn is supplied to the heat pressing in an imperfectly stretched condition. Provided that the yarn is perfectly stretched to the maximum crimp elongation, the fibers in theyarn configuration are put in a substantially and lengthwisely straightened disposition as shown in FIG. 4 and there can be almost no interfiber crossing as is in the case of the present invention. This is the usual case with the conventional processof the transverse crosssectional deformation by heat pressing. In other words, the enhanced orientation of the componental fibers in the yarn configuration by the perfect stretching results in poor inter-fiber crossing superimposition.

' Referring to the illustration in FIG. 5A, an example of the fibers locationally deformed in their transverse cross sections according to the method of the present invention is shown, wherein the fibers 19 are provided with transverse cross-sectionally deformed portions 21 at random along the length thereof. This is also confirmed through reference to V the photographic representation shown in FIG. 5B.

Microscopic observation is applied also to the transverse cross-sectional profile of the fibers in the dispositions before and after the dry heat pressing of the present invention. In the case of the example shown in FIG. 6A, the fibers composing the yarnare provided with a round transverse cross-sectional profile. By application of the dry heat pressing operation, the transverse cross-sectional profile of the fibers are deformed into a relatively flattened pattern as shown in FIG. 6B. This is confirmed also through reference to the photomicroscopic representation shown in FIG. 6C.

In the case of the example shown in FIGS. 7A and 7B, the componental fibers are provided with. a trilobate transverse cross-sectional profile and, through the application of the dry heat pressingoperation, the profiles are apparently deformed. Reference should be made to the photomicroscopic illustration given in FIG. 7C.

It is empirically confirmed that the fibers having a trilobate transverse cross section are most suitable for use of the end product for mattings such as carpets, when the fibers are treated by the method of the present invention. In this connection, however, it should be understood that the method of the present invention can be applied to the fibers of other transverse cross-sectional profiles with desirable results.

As is already understood from the foregoing description, the dry heat pressing is the key element in the method of the present invention and the resultant quality of the yarn is majorly dependent upon the processing conditions in this dry heat pressing operation such as the extent of stretch, the temperature at the pressing in relation to the temperature in the foregoing steam heating and the pressure applied to the yarn during the heat pressing.

As is understood from the definition given in the opening part of this specification, crimp dimension index is a measure for indicating the dimensional feature of the crimps possessed by the relevant fiber. When the value of the crimp dimension index is equal to l, the fiber is provided with crimps of perfectly twodimensional configuration whereas, when the value of the crimp dimension index is equal to 1r/2, the fiber is provided with crimps of perfectly three-dimensional configuration. It is empirically confirmed that the appearance of the end products made up of the yarn is considerably degraded when the value of the crimp dimension index exceeds 1.32. So, it is desirable that the value of the crimp dimension index possessed by the fibers composing the yarn of the present invention should not exceed 1.32. On the other hand, the threedimensional configuration of the crimps are considerably lost when the value of the crimp dimension index is smaller than 1.1. So, in order to provide the yarn of the invention with moderate bulkiness, it is desirable that thevalue of the crimp dimension index possessed by the componental fibers should be 1.1 or larger. In conclusion, the preferable crimp dimension index to be possessed by the fibers composing the yarn of the present invention should be in a range from 1.1 to 1.32.

In the first place, the optimum extent of stretch of the yarn in the heat pressing operation must be discussed in relation to the maximum crimp elongation of the fibers composing the yarn, reference being made to the graphical representation given in FIG. 8. In FIG. 8, the extent of torque residual in the resultant yarn is taken on the ordinate whereas the extent of the stretch in the heat pressing operation with respect to the maximum crimp elongation is taken on the abscissa. The curve a is for the heat pressing temperature higher than the foregoing steam heating temperature by 10 C, the curve b for 20 C, the curve c for 40 C and the curve d for C. The result shown in the graph was obtained concerning nylon yarn. In the preparation of the specimen nylon yarn, a material nylon yarn of 1,260 denier fineness and containing 60/2 filaments was subject'ed to the false twisting operation. The temperature in the false twisting was 138 C, the number of the false twists was 850 TPM, the load applied to the yarn was 0.1 g/denier and the yarn wasprocessed for 0.7 second. Next, the false twisted yarn was processed through the heatpressing of the present invention for 0.29 second at a pressure of 2.4 g/denier. From the result shown in the graph, it is clearly observed that the extent of torque residual in the resulting yarn increased, regardless of the temperature in the heat pressing, at the percent stretch smaller than percent. This increase in the residual torque means the lowering in the elasticity against compressing and the development of loop-shaped crimps of the resultant yarn, the latter development causing degradation of the appearance of the end product made of the yarn. On the contrary, when the percent stretch exceeds 95 percent of the maximum crimp elongation, there results the lowering in the bulkiness of the resultant yarn causing insufficient compression property of the end product made of the yarn.

The relationship between the crimp dimension index and the heat pressing temperature additional to steam heating temperature is shown in FIG. 9 for various per.- cent stretch, the former being taken on the ordinate and the latter being taken on the abscissa. In the illustration, the curve a is for 75 percent stretch, the curve b is for percent, the curve 0 for percent, the curve (1 for percent, the curve e for percent and the curve f for percent stretch. In this confirmation experiment, a nylon yarn of 840/3 denier fineness containing filaments was processed firstly to false twisting operation at a temperature of 137 C and a loading of 0.12 g/denier for 0.75 second. The number of the imparted false twists was 1,000 TPM. After this false twisting, the yarn was processed to the heat pressing operation of the present invention for 0.33 second at a pressure of 2.4 g/denier. In this experiment, it was confirmed that the fibers composing the material yarn fused to each other when the heat setting temperature exceeded 70 C above the steam heating temperature and the crimps were perfectly eliminated from the fibers, thereby the compression elasticity of the end product made of the yarns being considerably lowered. On the contrary, then the heat pressing temperature became lower than the steam heating temperature, crimp dimension index exceeded the above mentioned upper limitvalue, thereby the appearance of the end product being lowered and torque being retained in the yarn obtained.

From the above-described experimental results, it is confirmed that, as far as the 'nylon yarn is concerned, the heat'pressing operation is advantageously carried out at a percent stretch from 75 to 95 percent of the maximum crimp elongation and a temperature higher than the steam setting temperature by from to 80 C more preferably from 10 to 70 C. This is clearly confirmed through reference to the graphical representation given in FIG. 10, wherein percent crimp potentialization is taken on the ordinate and extent of stretch in the heat pressing in is taken on the abscissa. In the drawing, the curve a is for the heat pressing temperature higher than the foregoing steam heating temperature by 0 C, the curve b for 10 C, the curve 0 for 20 C, the curve d for 30 C, the curve e for C, the curve f for C, and the curve g for C. From-this illustration, it willbe understood that the percent crimp potentialization can be maintained larger than 40 percent when the percent stretch is in a range from 75 to 95 percent and the temperature is higher than the steam heating temperature by from 0 to C. The result shown-in FIG. 10 was derived from the results shown in FIGS. 8 and 9. For a further confirmation purpose, relationship between the degree of bulkiness and the heat pressing temperature is shown in FIG. 11 for the nylon yarn tested in the experiment of FIG. 9. In the illustration, the curve a is for percent stretch, the curve b for percent stretch, the curve c for percent stretch, the curve d for percent stretch, the curve e for percent stretch and the curve f for percent stretch.

The confirmative experiment was carried out concerning the polyester yarn also as shown in FIG. 13, wherein crimp dimension index is taken on the ordinate and heat pressing temperature additional to steam heating temperature is taken on the abscissa. In the il lustration, the curve a is for 70 percent stretch in the sense abovementioned, the curve b for 80 percent stretch, the curve 0 for 95 percent stretch and the curve d for 100 percent stretch. Similar to the result observed in FIG. 9, the fibers composing the yarn fused to each other when the temperature exceeds 70 C higher than the steam heating temperature and the residual torque was observed when the temperature became lower than the steam heating temperature. In this experiment, a polyester yarn of 1,000 denier fineness containing 96 filaments was processed to the false twisting operation for 0.8 second at a temperat ure of 165 C and a loading I of 0.1 g/denier. The number-of the false twists was 1,000 TPM. After this false twisting, the yarn was further processed to the heat pressing operation for 0.35 second at a pressure of 4 g/denier.

Relationship between the heat pressing temperature and degree of bulkiness of the resultant yarn is illustrated in FIG. 13, wherein the curve a is for 80 percent stretch, the curve b for 95 percent stretch and the curve c for 100 percent stretch. The result obtained was the same with that obtained in the case of the nylon yarn.

Further confirmative experiment was carried out concerning the acrylic yarn and the result was as is shown in FIG. 14, wherein the full line is for the crimp dimension index and the dotted line is for the degree of bulkiness. In the experiment, an acrylic yarn of 490 denier fineness containing 49 filaments was processed to the false twisting operation for 0.75 second at a temperature of 135 C and a loading of 0.08 g/denier and the resulting number of twists was 1,050 TPM..Next, the false twisted yarn was processed to the heat setting of the present invention for 0.3 second at a temperature of C and a pressure of 2 g/denier. As is apparently understood from the shown result, the crimp dimension index exceeds the upper limit value at a stretch smaller than 75 percent whereas the degree of bulkiness is lowered considerably at a stretch larger than 95 percent.

As to the effect of the heat pressing temperature, the temperature higher than 80 C above the steam setting temperature causes considerable lowering in the strength of the yarn manufactured whereas the temperature lower than the steam setting temperature leads to undesirable increase in the crimp dimension index.

Confirmative experiments were also carried out concerning the pressure to be applied to the yarn during the heat pressing operation. The obtained results are shown in FIG. 15 for the nylon yarn and in FIG. 16 for the polyester yarn. In the both illustration, the full line is for the crimp dimension index and the dotted line is for the degree of bulkiness of the yarn obtained. The extent of the stretch in the heat pressing was 85 percent for the nylon yarn and 82 percent for the polyester yarn.

In the arrangement shown in FIG. 1, the heat pressing assembly is provided with two sets of

press rollers

14a and 14b in a peripheral pressure contact with the heated drum 13. However, the number of press rollers can be selected as desired. For example, in the arrangement shown in FIG. 17, the assembly is provided with three sets of

press rollers

14a, 14b and 140. In a general statement, it is desirable to increase the number of press rollers and to decrease the contact pressure of the press rollers with the heated drum for a better deformation effect of the heat pressing operation. A modification of the assembly derived from this conception is shown in FIG. 18, wherein the assembly includes the heated drum 13, a rotational roller 22 mounted at a selected distance apart from the heated drum 13, a pair of heated plates 23 located in between the two

elements

13 and 22 and a press roller 24 mounted in a peripheral contact with the heated plate 23. The crimped yarn lb is advanced as shown with an arrow and wound for several times in contact around the

elements

13, 22 and 23. During this circulation, the yarn is pressed onto the heated surface of the heated plate 23 by the press roller 24 and is issued from the assembly in the form of the crimp potentialized yarn towards the package (not shown).

As is already explained in the foregoing description, the dry heat pressing operation employed in the'present invention has two technical effects on the yarn to be processed, one being transverse cross-sectional deformation of the componental fibers and the other being the potentialization of the crimps once formed on the componental fibers. In this conception, for a further confirmation of the potentialization effect on the crimps, an additional process for ascertaining this additional potentialization can be introduced into the arrangement shown in FIG. 1. In FIG. 19, one embodiment of such an additional arrangement is shown, which arrangement should be inserted in between the second take-up rollers and the winding up stage onto the package 17. In the shown arrangement, the third take-up rollers 27 having a surface speed to some extent faster than that of the second take-up rollers is provided at a location just upstream of the package 17. In between the two sets of take-up

rollers

15 and 27, there is provided an additional heater 26. The additional heater 27 may be formed either in the direct contact type or indirect heating type. However, in the practical yarn manufacturing, the additional heater 27 should preferably be formed in the indirect heating type for obviation of the undesirable tension effect on the processed yarn by abrasive contact with the heating surface. Because the surface speed of the third take-up rollers 27 is selected to some extent faster than that of the 2nd take-up rollers 15, the yarn 10 can be put in a stretched condition during this additional heating process. The above-described difference in the surface speeds should be so selected that the stretch is me range from the stretch in the heat pressing and the maximum crimp elongation, thereby potentialization of the crimps imparted to the fibers can be accomplished perfectly.

The temperature to be employed in this additional heating process should be pertinently selected so that the resultant percent crimp potentialization of the fiber composing the acquired yarn should be 40 percent or larger.

The following examples are illustrative of the art of the present invention, but are not to be construed as limiting the same.

EXAMPLE 1 Nylon multifilamentary yarn of 840 total denier containing 45 monofilaments was processed through the arrangement shown in FIG. 1 attached with the arrangement shown in FIG. 10 under three different processing conditions listed in Table 1. Aside from this, same type of material multifilamentary yarns were processed, prior to the dry heat pressing stage, through the conventional Italian throwing machine and a false twisting operation with application of dry heating under the processing conditions listed in Table 1, respectively.

TABLE 1 Sample I 2 3 4 5 Nos.

Italian throwing machine Machine False twisting spindle Crimp- 1000 1000 800 1000 600 ing . Heating temperaures in "C *Heating times in sec. Percent stretch *Pressing temperature in C 137 I37 I37 I Heat- I82 182 182 I82 182 press- *Pressing time in sec Pressure in kg *Percent stretch ing 0.36 0.36 0.36 0.36 0.36

Additional potential- Ization temperature in C 180 180 I80 180 I80 Heating time in sec In the table, the value of the percent stretch means the length of the fiber under stretch with respect to the length thereof under the maximum crimp elongation.

The resultant characteristic features of the respective specimen yarn was as is shown in Table 2.

tum/50 cm In the measurement of the torque, a yarn was sampled from the package without imparting unnecessary twists thereto. Next, the yarn was bent in a U-form and subjected to a loading of 0.1 g/denier. After fixing the yarn portion of 50 cm from the downward end, the yarn was unloaded for a free shrinkage. The number of the turningof the yarn by this free shrinkage was measured and recorded.

As is apparent from the result shown in FIG. 2, in the case of the sample No. 4 wherein dry heating was employed in the false twisting operation, considerable reductions in the number of crimps per 1 inch length of the fiber and in the value of percent crimp potentialization were recognized. Further, in the case when the Italian throwing machine was used, considerable increase in the residual torque was confirmed in addition to the considerable reduction in the crimp density and crimp potentialization effect.

EXAMPLE 2 Number of false twists in TPM 1500 Temperature in the false twisting in C 135 Temperature in the heat pressing in C 185 Percent stretch in the heat pressing 88 Pressure in the heat pressing in kg 2.7 Temperature in the potentialization in C 175 Percent stretch in the potentialization 92 The yarn obtained was provided with the following characteristic features.

Crimp dimension index 1.24 Percent crimp potentialization 45 Degree of bulkiness in cm lg 21.4

it should be noted that, in the art of the present invention, the false twisting with steam heating is combined with the subsequent heat pressing, thereby particular advantages being brought about as is apparent from the following description.

In general, when the yarn is purposed for use in carpets as the pile yarns, the yarn is required to have crimps whose number is defined by the following formula.

wherein N number of crimps per 30 mm maximum crimp elongation.

Aside from this, the numbers of crimps in the abovedefined sense imparted to the yarn in the steam heat false twisting and in the dry heat false twisting are defined as follows in relation to the fineness of the supplied material yarn.

wherein N, Number of crimps per 30 mm maximum crimp elongation of the yarn processed through the steam heat false twisting.

N Number of crimps per 30 mm maximum crimp elongation of the yarn processed through the dry heat false twisting.

From the above presented three relationship, it is mathematically deduced that, for the purpose of obtaining a crimped yarn suitable for use in the carpet as the pile yarns, the steam heat false twisting process can accept the material yarn having the fineness up to 1,470 denier whereas the dry heat false twisting process cannot accept the material yarn having the fineness larger than 800 denier. So, it is concluded that the dry heat false twisting process is not suitable for processing TABLE 3 Steam heating Dry heating Temperature in C 137 185 Number of twists False in TPM 1000 1000 twisting Setting time length in sec 0.75 1.20 Tension in t/denier 0.12 0.12 Number of crimps per 30 mm maximum crimp elongation 15.8 9.7 34.6 26.8 Percent crimp elongation 66.4 36.6 Percent crimp potentialization 48 27 Crimp dimension index 1.46 1.42 Apparent shrinkage in 81 62 Percent shrinkage in boiling water 5.3 5 .9

The difference in the crimp potentialization effect is further enlarged after the subsequent application of the heat pressing as is understood from the result shown in Table 4.

TABLE 4 Steam Dry heating heating Temperature in "C 165 Heat Heat pressing time length in sec. 0.33 0.33 0.33 press- Pressure in g/denier 4.8 4.8 4.8 mg

Percent stretch with respect to the maximum 82 82 82 crimp elongation Number of crimps per 30 mm maximum crimp elongation 16.4 9.7 8.6

Percent crimp elongation 17.8 13.6 9.5 Percent crimp potentialization 57 5 8 Percent crimp retainability 61 29 32 Crimp dimension index 1.23 1.38 1.27 Apparent shrinkage in 26 34 23 Snarl index 8.5 25 9 Percent shrinkage in boiling water 3.4 5.2 4.9

As is apparent fromthe results shown in Table 3, the steam heating can provide the resultant yarn with larger number of crimps than that provided by the dry heating. As a solution to this, it may be proposed to use filaments of smaller fineness in the dry heat false twisting, thereby increasing the resultant number of crimps possessed by the obtained yarn. However, this decrease in the fineness of the material filament is accompanied with undesirably decrease in the amplitude of the crimps developed on the resultant yarn and the obtained yarn is not crimped suitably for use as a material for carpet piles.

It is empirically confirmed that the amplitude u of the crimps developed on the resultant yarn is defined by the following formula.

wherein c ,u. Amplitude of the crimps in mm.

D Fineness of the material yarn in denier. The

value of the crimp amplitude optimum for use as the material for the carpet piles is defined by the following formula.

wherein N Number of crimps per 30 mm maximum crimp elongation. Combining the already presented mathematical relationships, the following is deduced.

For the steam heat false twisting 5.1 5 Np. 5 6.9 For the dry heat false twisting 3.1 5 N 5 4 also understood from the reference to the following Tables 5 and 6.

TABLES Process- Present invention Dry heat ing condition false twisting Fineness of the material nylon 630 840 1260 630 840 1260 yarn in denier Temperature inC 135 137 137 182 185 190 False Number of twistinTPM 1160 1000 850 1160 1000 850 twist- Settingtime ing length'insec 0.75 0.75 0.75 1.1 1.2 1.4 Tension in g/denier 0.12 0.12 0.10 0.12 0.12

0.11 Temperature inC 173 168 165 165 163 158 Heat Pressing time lengthinsec 0.33 0.33 0.33 0.30 0.33

0.38 press- Pressure in 'ing g/denier 3.2 3.2 3.2 3.2 3.2 3.2 Percent stretch 82 82 82 82 82 82 Thusly obtained crimped yarns are plied and twisted together, respectively and the functional property thereof is as shown in Table 6.

TABLE6 l resent invention Dry heat false twisting What we claim is:

1. A method of manufacturing textured yarn comprising: providing a crimped yarn composed of numerous crimped and entangled together thermoplastic synthetic fibers; partially removing only some of the crimp from said crimped fibers to obtain a partially crimped yarn composed of partially crimped fibers mutually intercrossed and entangled with each other at longitudinally spaced random locations along the length of the fibers; heating and pressing together said partially crimped fibers to contact the fibers at their mutually intercrossed locations with sufficient pressure and at a sufficient temperature to effect permanent transverse deformation of the fibers at their contact points; and terminating the heating and pressing together of thedeformed fibers to obtain a textured yarn composed of numerous fibers having longitudinally and randomly spaced transverse deformities.

2. A method according to claim 1, wherein said heating and pressing step includes applying sufficient force to said partially crimped fibers in a direction substantially transverse to the partially'crimped yarn axis to transversely deform the fibers at their contact points into mutually flattened portions.

3. A method according to claim; 1, wherein said heating and pressing step'includes pressing together said partially crimped fibers within a pressure range of from 2 to 10 gm/denier.

4. A method according to claim 1, wherein said partially removing step comprises longitudinally stretching said crimped yarn at a stretch effective to remove only some of the crimp from said crimped fibers.

5. A method according to claim 4, wherein said longitudinally stretching step comprises longitudinally stretching said crimped yarn at a. stretch sufficient to remove to 95 percent of the crimp from said crimped yarn.

6. A method according to claim 1, wherein said heating and pressing step includes pressing said partially crimped fibers at least once against a heated surface.

7. A method according to claim 1, wherein said providing step comprises providing a yarn composed of numerous thermoplastic synthetic fibers, and false twisting said yarn to impart crimps to the fibers accompanied by steam-setting the crimped fibers at a given temperature to form crimped yarn; wherein said partially removing step comprises longitudinally stretching said crimped yarn at a stretch effective to remove only some of the crimp from said crimped fibers; and wherein. said heating and pressing step. includes pressing'the stretched yarn at least once against a heated surface to effect heating thereof to a temperature higher than said given temperature.

8. A method according to claim 7, wherein said partially removing step comprises longitudinally stretching said crimped yarn at a stretch sufficient to remove 75 to 95 percent of the crimp from said crimped yarn; and wherein said heating and pressing step includes heating said stretched yarn to a temperature 10 to 70 C. higher than said given temperature.

9. A method according to claim 7, wherein said false twisting step comprises first false twisting said yarn in one direction during one stage of false twisting and then false twisting the twisted yarn in the opposite direction during a second stage of false twisting.

10. A method according to claim 7, further including additionally dry heating said textured yarn to a temperature of from 0 to C. higher than said given temperature while stretching said textured yarn at a stretch larger than said stretch employed during said partially removing step.

7 I i I! l

Claims

1. A method of manufacturing textured yarn comprising: providing a crimped yarn composed of numerous crimped and entangled together thermoplastic synthetic fibers; partially removing only some of the crimp from said crimped fibers to obtain a partially crimped yarn composed of partially crimped fibers mutually intercrossed and entangled with each other at longitudinally spaced random locations along the length of the fibers; heating and pressing together said partially crimped fibers to contact the fibers at their mutually intercrossed locations with sufficient pressure and at a sufficient temperature to effect permanent transverse deformation of the fibers at their contact points; and terminating the heating and pressing together of the deformed fibers to obtain a textured yarn composed of numerous fibers having longitudinally and randomly spaced transverse deformities.

2. A method according to claim 1, wherein said heating and pressing step includes applying sufficient force to said partially crimped fibers in a direction substantially transverse to the partially crimped yarn axis to transversely deform the fibers at their contact points into mutually flattened portions.

3. A method according to claim 1, wherein said heating and pressing step includes pressing together said partially crimped fibers within a pressure range of from 2 to 10 gm/denier.

5. A method according to claim 4, wherein said longitudinally stretching step comprises longitudinally stretching said crimped yarn at a stretch sufficient to remove 75 to 95 percent of the crimp from said crimped yarn.

7. A method according to claim 1, wherein said providing step comprises providing a yarn composed of numerous thermoplastic synthetic fibers, and false twisting said yarn to impart crimps to the fibers accompanied by steam setting the crimped fibers at a given temperature to form crimped yarn; wherein said partially removing step comprises longitudinally stretching said crimped yarn at a stretch effective to remove only some of the crimp from said crimped fibers; and wherein said heating and pressing step includes pressing the stretched yarn at least once against a heated surface to effect heating thereof to a temperature higher than said given temperature.

8. A method according to claim 7, wherein said partially removing step comprises longitudinally stretching said crimped yarn at a stretch sufficient to remove 75 to 95 percent of the crimp from said crimped yarn; and wherein said heating and pressing step includes heating said stretched yarn to a temperature 10* to 70* C. higher than said given temperature.

10. A method according to claim 7, further including additionally dry heating said textured yarn to a temperature of from 0* to 80* C. higher than said given temperature while stretching said textured yarn at a stretch larger than said stretch employed during said partially removing step.