CA1080457A - Fiber texturing method - Google Patents
Fiber texturing methodInfo
- Publication number
- CA1080457A CA1080457A CA299,628A CA299628A CA1080457A CA 1080457 A CA1080457 A CA 1080457A CA 299628 A CA299628 A CA 299628A CA 1080457 A CA1080457 A CA 1080457A
- Authority
- CA
- Canada
- Prior art keywords
- fiber
- irradiated surface
- laser
- irradiated
- thermal gradient
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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- Chemical Or Physical Treatment Of Fibers (AREA)
- Yarns And Mechanical Finishing Of Yarns Or Ropes (AREA)
Abstract
Abstract In order to texture fibers such as filaments or yarns, a beam of electromagnetic energy, preferably that from a laser source, is directed upon a fiber as it moves past the zone of the directed beam. The frequency of the beam is adjusted so that its wavelength falls within an absorption band of the fiber. As a result, that side of the fiber upon which the beam impinges will be readily heated and, at the same time, provide a shading effect for the non-irradiated side of the fiber to establish an internal differential thermal gradient across the fiber. This differential internal thermal gradient imparts a texturing twist to the fibers. A focusing lens may be inserted between the laser source and the fiber so that the area of the beam approximates that of the area of the side of the fiber irradiated by the beam. Also, during the texturing process, the fibers may be elongated to enhance the effect of the differential thermal gradient.
Description
lOB0457 i FIELD OF Tt,~E INVE~TION
The present invention i9 directed to a technique o~ texturing fibers, including monofilaments ~nd yarns, in which a beam of electroma~netic energy is directed upon the fiber S l~ and the fiber is asymmetrically heated.
11 .
' DESCRIPTION OF TH~ PRIOR ART
¦ For the purpose of imparti=g a texture e~fect to tfiSers such as spun yarns and filamenes~ various techniques such ¦l aq direct conduction heating by passing the yarn over a heated plate and irradiation with electromagnetic energy, such as from ; a laser source, have been proposed. When a source of direct cond~ction heating, such as a hot plate, is employed, only a ¦very s~all part of the heat output of the plate is imparted ,jto the yarn as it passes over the plate and a considerable amount lS of heat is irradiated into the surrounding space, resulting in !!a considerable amount o~ heat loss an~ the need to employ special Il , e~uipment to remove the excess heat generated in the environment ~urrounding the yarn.
As the technology has become more sophisticated, the treat~ent of yarns by applying heat fro~ a laser beam has developed. One such treatment is described in East Germany I ~ ¦Patent No. 106,206, issued ~une 5, 1974. According to the ! Idescription in the patent, a colllmated laser beam is employed ¦to heat-treat a runnlng filament or filament bundle. The de~cription in the patent ind$cates that the contactless transrer ¦ ~ o~ heat by means of laser radlation reqults in a better heating throughout the filament and that inhomogeneities acros3 the ment cro~s-sactlon are elimlnated. Namely, thiq patent deal3 ~th symmetrical heating o~ a ~ilament by laser radlation.
. . . .
~ - 2 - ' ~
''1 I
I!
~ n Japanese Patent Publicatlon No. 73-858~3, j Novem~er 13, 1913, there is described a technlque for treating yarn by a laser beam the spot diameter of which is laraer t~an ¦ the dia~eter of the yarn to be treated. A zig-zag laser beam 5 ~ is formed through which the yarn to be treated passes so that the yarn crosses the zig-zag laser beam at a plurality of po~itions for heat treatment. Through this process, the yarn ; is heated at its opposite sides and, accordingly, is heated uniformly throughaut.
10 I A techni~ue wherein asymme~rical heating of fibers by laser radiation is employed is described in French Patant o. 2,049,637, published Narch 26, 1971. According to the !l dsscription in the patent~ spun yarns~ or fila~ents~ are ¦¦ disposed on a curved or flat surface while applying the heat 15 ! from a laser source to part of the surface of the spun yarn.
- ~imited and localized laser action causes heating of the surface, , l, resulting in a differential thermal effect in cross-section in j' the af~ected zone of the filament. The filamentS may also be ' 9ub~ected to tension during the process. When the filament ~ ¦, cools, subsequent to heat treatment, it tends to coil-up, producing a texturing effect. A si~ilar asymmetrical heatins by the use of laser energy i9 described in U.S. Patents 3,523,345 and 3,678,142.
. In the above-referred to patents aescribing 25 asymmetrical laser heating of filaments or yarns, the differential ther~al gradien~ i5 effectively established by creating an ~ergy gxadient in a spacial zone through which the fiber passes , during a texturing run. For this purposa, a lens is provided ln order to focus tha laser beam to a small ~pot. The lens r 30 employed should preferably hav~ a short focal length to establish . a ~u~ioient energy gradlent in the space occupied by the ~ -~
_ 3 ~ j ~, ~ . . .~
.... .. .. . .. . . . .. ~ . .. . .. ~
11 ~o~ s7 ,i , ' i filaments or yarnei ln order to lnduce a reasonably well developed ¦, thermal gradient within the yarn beneath the surface of the spot , impinged by the laser beam. In other words, it i5 a concentrated ,' intensl ty of laser energy which creates the thermal gradient and 5 ; the polymeric mateirials of which the fibers are made are ', virtually transparent at the wavelengths of the laser beams " employed.
A basic disadvantage of this type of laser heating . ~ the prai~tical inability of focusing or aiming a highly 10 ~I concentjrated laser beam on a particular spot of a fine filament il a~ the filament passes throu~h the ~one of the beam. The ~ila-e ~ ~ m~nts are usually unwound ~rom.a supply package and pass-over rollers to be heated by the laser beam. During the cou.rse of ~' ~ovement, there is translational displacement of the filaments across the beam, so that difficulties in maintaining proper i ~ocus on only a part of the fiber becomes severe.
- ; :
- ~¦ SU~MARY OF T~E INVEN~ION
. ¦i . Xn accordance with the present invention,.asymmetri-¦¦ cal hea~ing of fibers, such as filaments or yarns, for the j purpose of texturing the fibers, is achieved by irradiating the . fibers with a laser beam, the ~requency of which is adjusted so that the wavelength of the laser beam falls within the . absorption band of the fibers being treated. By tuning or ,~
; : ~atching the wavelength of the iaser beam to that of an ~ - 25absorption band of the fllament, the surface of the filament . . ! lrraaiatea by thisi laser beaiTi readlly absorbs substantially all ¦ o~ the a~aila~l~s energy in the beam to heat that surface of the . filament and crea~ a dif~erential thermal gradient within the . ¦ . .~13ment ~om .the lrradiated side ~iQ the shaded or nonirradiated .30 i~ild~i. Shi~ thermal dlFfer~&,tial grad~ent lmpart~i 1~8~glS7 iatent bends or twists to the f.i.bers so that the ~ibers are textured by the heat involved in later process steps such as scouring or dyeing.
A significant advantage as compared to prior art asymmetrical heating techniques is the lack of a need for precise control of focusing the beam into a fine spot with the hope that the spot continuously impinges on only a portion of the surface of the fiber. In other words, once the wavelength of the laser beam and the absorpt.ion band of the ~iber are matched with each other, the beam and the fiber do the work themselves of providing the differential thermal gradient;
accordingly, complex control equipment for insuring that the filaments pass along a prescribed path and for accurately focusing the laser beam into a small spot is unnecessary.
The texturing effect of the present invention can be enhanced by somewhat elongating the yarn as it is irradiated by the laser beam tuned to a primary absorption band of the yarn. The efficiency of the heating can be improved by pro- .:
viding a lens to control the diameter of the beam to that approxima$ing the size of the yarn.
In summary of the above, therefor, the present ., invention broadly provides, in a method of texturing polymeric fibers including filaments or varns, in which a beam of electro-magnetic energy is caused to impinge upon a fiber, the improve-~ ment wherein the beam of electromagnetic energy employed is a ; laser beam having a wavelength falling within an absorption J, band of the polymeric material of the fiber and the beam is ~.
~' caused to impinge upon a side of the fiber so that the polymeric 1~
., !
~1 .. -5- , ,: -:: :: : :, . : , :,: . :- . :: : . :~ ,: ::, .. . :. :
L5'7 material of the fiber beneath the irradiated surface of the fiber upon which the beam is directed effectively shades the remaining non-irradiated surface of the fiber whereby a differential thermal gradient i5 created within the fiber from the irradiated surface to the non-irradiated surface.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a schematic illustration of an arrangement for texturing fibers by laser heating; and Fig. 2 is an enlarged schematic -view of the irradiation of a fiber by a focused laser beam.
DETAILED DESCRIPTION OF THE PREFERRED
.
EMBODIMENTS
Referring to Fig. 1, there is shown a laser source ` .
~' 5a- ~
.
- ; , .. . - ,,~, ,,,: . .. , :; - : . - .
1, which may ~onqlst of a carbo~ dioxide laser, h~ving a tunable , outp~t freguency over a wavelength range from 9.473 microns to 10.858 microns. A beam la is emitted by ~he laser and is ,1 optionally focused by a lens 2 onto one sid~ of a running ~ibcr ~, 3, pacising over a pair of tensiioning rollers 4 and 5. A beam , 8t~p 6 ~ 9 provided to intercept that portlon of the beam which ¦1 ~ypasses the flber 3.
¦ ~ The fiber 3 which is to be textured is supplied from !! a fiber supply package 7 and driven over rollers 4 and 5 and is ~ eventually taken up in a fiber taXe-up 8. During the oourse of ', travel of the fiber 3 o~er the rollers 4 and 5, the fiber 3 may .
' be elongated.
j~ . . . . .. . . . .. .. . .
; l In one specific example in which the effect of the differential gradient heating by the tuned laser arrangement - 1 according to the present invention was measured, the fiber ~' I tested was 297 denier saran monofilament, imparted with an . ~ nlon~ation o~ approxit~ately 5~ and travelling across the laser - 1I Leam la at a speed of about 45 feet/min. Saran monofilament has an ab~orption band in the area o~ 9.6 microns so that the ¦ laser wa3 tuned to one o~ its tunable requency lines at , 1 9.586 microns and ru~ at moderate ~ower without using the lc~3 2 to focu~ the bea~.
~ ll Vpon leavinq the last go~et, the saran monofilament - 2S - exhibited helical characteristic~. The filament was placed in ¦ ~o~llny water for ap~roximately 30 seconds to allow or ¦
¦ approximately 4~ 3hrinkage to occur in the non-treated regions I ~
o~ ~hR fllamen~. The helix th~n exhibited a~much smaller, ~;
¦ sliqhtly v3rying radius o~ ~ur~ature with reversals o~ the I hellx.
.'.' , ' ' _~ .
,., . I . , ' ~ ' ,, ' . .
.
.: . . .:: . ~. ~ . . -1~ ( I
~ 5 ', !
Wlth respect to the irradiatlon oE the flber ltself ~y th~ laser ~am la, Fig. 2 shows the fiber 3 in , enlarged cross-section, an irradiated portion 3a o~ which is , directly impinged upon by the laser beam la. With the 5 , frequenry of the laser beam la being tuned to an absorption ` band of the fiber 3, the irradiated portion 3a will rapidly 'I a~sorb ~he energy from the beam la by molecular resonance ¦ effects. Since the shaded side is not directly ixradiated by Il the beam la, a differential thermal gradient is created within 10 L the fi~er 3, 50 that the fiber 3 is asymmetrically heated and a textured fiber is obtained. The focusing lens 2 adjusts the 1 diameter of the beam la in the zone through which the fiber 3 - I pa3ses to approximately the size of the fiber 3 so as to make . . I the energy coupling ~ore efficient.
15 jl 0~ course, the particular laser employed will ; , depend upon the ahsorption band of the yarn to be treated and the present invention is not exclusively limited to the above-!¦ referred to C02 laser This laser has been descri~ed in ¦i ~onnection with the exemplary fiber saran monofilament since the laser output frequency and the absorption band ! cha~acteristics of this particular flber can be matched when the laser is a C02 laser. For other ~ibers having different absorption band characteristics, tha laser will be chosen so that it can be tuned to the absorption band of the fiber 25 being treatud.
As ha~ been descrlbea above, in accordance with ¦ the present invention, a fiber such as a filament of a yarn can . ¦ be textured by a3ymmeeri~ heating by laser irradiation of one ¦ slde of the fiber with the laser being tuned so that $ts ¦wav~length matcheg an absorptlon band of the ~iber. The texeure I ¦typically produced by such asymmetric heating la a helix. The 7 ~
, 11 . " . ~ , . I
. , ~ LS~
. ., ¦1 actual physical parameters o the helix, namely, the diameter and pitch can be calculated on the basis of known factors. The , diameter of the helix is basically influenced by filament i diameter, the elDngation set into the filament by the laser, 5 1 and shrinkage induced by hea~, steam, or even a dye b~th for the yarn. Cons$dering the cross-sectional diameter of the ~iIament to be df and the elongation along the outer edge of the filament having the largest radius of curvature to be the value x and the shrinkage along the inner edge of the filament I ha~in~ the smallest radius of curvature to be the value y, then I the diameter of the helix DheliX can be calculated to be:
-- Ij -~,i Dhel ix d~
'. , 15. ~ i~
1 ' ` 'I'i , ' `
J Il ~he pitch of the helix ~namely the number of turns ¦ per inch) is influenced by the twist of the feeder yarn/filament prior to treatment. If the feedes filament~yarn has no twist tand no twist is induced during the heating process, ehen the ao relaxed hel~x will assume a limiting pitch, namely a unit length of coil/d~ ~ number of turns/unit lengtb. This evaluatioj can bs modified if the filament~yarn has been twisted prior to trcatment. The effect is to modulate the ideal halix in such 3 ' ; ~anner as to cause the helix diameter to vary and also to cause ~, 25 ~ I the helix directlon to re~erse itself. This reversal of the ~elix i~parts further texturing to the fiber so that i~ can be 9~en that a combination of factors may be added to the basic ~i3ym~etxic heating in accordance with ehe pra3ent invention , to obtain a textured f'ber.
. . '.
~ a - ~
. . l .. . .... - ., . ,. ... , . - ... , , . . ... . - . :-.
-' 'I I
5~
! The yarn speed, namely the speed at whlch the yarn Il travels through the zone of the lasQr beam, ls a function of ! the power density of the laser that can be provided at the irradiation zone. The length of ti~e during which the yarn traverses this irr~diation zon~ is orders of magnitude larger i than the time required to couple the energy into the yarn, .I nam,ely, on ~he order of 10-1 seconds. It can be readily ¦i apprecia~ed~ accordingly, that ~y matching the absorption band il to thê wavelength of the laser, a very efficient coupling of thq energy in the laser beam to the fiber is obtained to impart the desired asymmetric heating to the fiber and achieve the aesired textured fiber. I ..
~¦. It will ~e appreciated that the fibers sultable I! for purposes of this invention are thermoplastic polymeric materials. Preferred are the fibers of textile yarns which - possess a finite but real elongation and which are susceptible !~ to boiling water shrinkage, e.g., on the order of at least 4~.
¦ 2xemplary of such materials are nylon, polyethylene, pDlyvinyl -- j chloride, polypropylene, acrylic resins such as the poiyacrylonitriles, polyesters, and ~he like.
¦ While I have shown and described several e~bodiments . ln accordance with the present invention, it is understood that ¦ the same is not limited thereto but is susceptible of numerous . ¦ changes and modifications as known to a person skilled in the I art, and ~ therefore do not wish to be limited to the details ~hown and de~cribed herein bu~ intend to cover all such changes I ~d moaifications as are obviou to one of ordinary skill in ¦ t~ ~rt-.
:.
The present invention i9 directed to a technique o~ texturing fibers, including monofilaments ~nd yarns, in which a beam of electroma~netic energy is directed upon the fiber S l~ and the fiber is asymmetrically heated.
11 .
' DESCRIPTION OF TH~ PRIOR ART
¦ For the purpose of imparti=g a texture e~fect to tfiSers such as spun yarns and filamenes~ various techniques such ¦l aq direct conduction heating by passing the yarn over a heated plate and irradiation with electromagnetic energy, such as from ; a laser source, have been proposed. When a source of direct cond~ction heating, such as a hot plate, is employed, only a ¦very s~all part of the heat output of the plate is imparted ,jto the yarn as it passes over the plate and a considerable amount lS of heat is irradiated into the surrounding space, resulting in !!a considerable amount o~ heat loss an~ the need to employ special Il , e~uipment to remove the excess heat generated in the environment ~urrounding the yarn.
As the technology has become more sophisticated, the treat~ent of yarns by applying heat fro~ a laser beam has developed. One such treatment is described in East Germany I ~ ¦Patent No. 106,206, issued ~une 5, 1974. According to the ! Idescription in the patent, a colllmated laser beam is employed ¦to heat-treat a runnlng filament or filament bundle. The de~cription in the patent ind$cates that the contactless transrer ¦ ~ o~ heat by means of laser radlation reqults in a better heating throughout the filament and that inhomogeneities acros3 the ment cro~s-sactlon are elimlnated. Namely, thiq patent deal3 ~th symmetrical heating o~ a ~ilament by laser radlation.
. . . .
~ - 2 - ' ~
''1 I
I!
~ n Japanese Patent Publicatlon No. 73-858~3, j Novem~er 13, 1913, there is described a technlque for treating yarn by a laser beam the spot diameter of which is laraer t~an ¦ the dia~eter of the yarn to be treated. A zig-zag laser beam 5 ~ is formed through which the yarn to be treated passes so that the yarn crosses the zig-zag laser beam at a plurality of po~itions for heat treatment. Through this process, the yarn ; is heated at its opposite sides and, accordingly, is heated uniformly throughaut.
10 I A techni~ue wherein asymme~rical heating of fibers by laser radiation is employed is described in French Patant o. 2,049,637, published Narch 26, 1971. According to the !l dsscription in the patent~ spun yarns~ or fila~ents~ are ¦¦ disposed on a curved or flat surface while applying the heat 15 ! from a laser source to part of the surface of the spun yarn.
- ~imited and localized laser action causes heating of the surface, , l, resulting in a differential thermal effect in cross-section in j' the af~ected zone of the filament. The filamentS may also be ' 9ub~ected to tension during the process. When the filament ~ ¦, cools, subsequent to heat treatment, it tends to coil-up, producing a texturing effect. A si~ilar asymmetrical heatins by the use of laser energy i9 described in U.S. Patents 3,523,345 and 3,678,142.
. In the above-referred to patents aescribing 25 asymmetrical laser heating of filaments or yarns, the differential ther~al gradien~ i5 effectively established by creating an ~ergy gxadient in a spacial zone through which the fiber passes , during a texturing run. For this purposa, a lens is provided ln order to focus tha laser beam to a small ~pot. The lens r 30 employed should preferably hav~ a short focal length to establish . a ~u~ioient energy gradlent in the space occupied by the ~ -~
_ 3 ~ j ~, ~ . . .~
.... .. .. . .. . . . .. ~ . .. . .. ~
11 ~o~ s7 ,i , ' i filaments or yarnei ln order to lnduce a reasonably well developed ¦, thermal gradient within the yarn beneath the surface of the spot , impinged by the laser beam. In other words, it i5 a concentrated ,' intensl ty of laser energy which creates the thermal gradient and 5 ; the polymeric mateirials of which the fibers are made are ', virtually transparent at the wavelengths of the laser beams " employed.
A basic disadvantage of this type of laser heating . ~ the prai~tical inability of focusing or aiming a highly 10 ~I concentjrated laser beam on a particular spot of a fine filament il a~ the filament passes throu~h the ~one of the beam. The ~ila-e ~ ~ m~nts are usually unwound ~rom.a supply package and pass-over rollers to be heated by the laser beam. During the cou.rse of ~' ~ovement, there is translational displacement of the filaments across the beam, so that difficulties in maintaining proper i ~ocus on only a part of the fiber becomes severe.
- ; :
- ~¦ SU~MARY OF T~E INVEN~ION
. ¦i . Xn accordance with the present invention,.asymmetri-¦¦ cal hea~ing of fibers, such as filaments or yarns, for the j purpose of texturing the fibers, is achieved by irradiating the . fibers with a laser beam, the ~requency of which is adjusted so that the wavelength of the laser beam falls within the . absorption band of the fibers being treated. By tuning or ,~
; : ~atching the wavelength of the iaser beam to that of an ~ - 25absorption band of the fllament, the surface of the filament . . ! lrraaiatea by thisi laser beaiTi readlly absorbs substantially all ¦ o~ the a~aila~l~s energy in the beam to heat that surface of the . filament and crea~ a dif~erential thermal gradient within the . ¦ . .~13ment ~om .the lrradiated side ~iQ the shaded or nonirradiated .30 i~ild~i. Shi~ thermal dlFfer~&,tial grad~ent lmpart~i 1~8~glS7 iatent bends or twists to the f.i.bers so that the ~ibers are textured by the heat involved in later process steps such as scouring or dyeing.
A significant advantage as compared to prior art asymmetrical heating techniques is the lack of a need for precise control of focusing the beam into a fine spot with the hope that the spot continuously impinges on only a portion of the surface of the fiber. In other words, once the wavelength of the laser beam and the absorpt.ion band of the ~iber are matched with each other, the beam and the fiber do the work themselves of providing the differential thermal gradient;
accordingly, complex control equipment for insuring that the filaments pass along a prescribed path and for accurately focusing the laser beam into a small spot is unnecessary.
The texturing effect of the present invention can be enhanced by somewhat elongating the yarn as it is irradiated by the laser beam tuned to a primary absorption band of the yarn. The efficiency of the heating can be improved by pro- .:
viding a lens to control the diameter of the beam to that approxima$ing the size of the yarn.
In summary of the above, therefor, the present ., invention broadly provides, in a method of texturing polymeric fibers including filaments or varns, in which a beam of electro-magnetic energy is caused to impinge upon a fiber, the improve-~ ment wherein the beam of electromagnetic energy employed is a ; laser beam having a wavelength falling within an absorption J, band of the polymeric material of the fiber and the beam is ~.
~' caused to impinge upon a side of the fiber so that the polymeric 1~
., !
~1 .. -5- , ,: -:: :: : :, . : , :,: . :- . :: : . :~ ,: ::, .. . :. :
L5'7 material of the fiber beneath the irradiated surface of the fiber upon which the beam is directed effectively shades the remaining non-irradiated surface of the fiber whereby a differential thermal gradient i5 created within the fiber from the irradiated surface to the non-irradiated surface.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a schematic illustration of an arrangement for texturing fibers by laser heating; and Fig. 2 is an enlarged schematic -view of the irradiation of a fiber by a focused laser beam.
DETAILED DESCRIPTION OF THE PREFERRED
.
EMBODIMENTS
Referring to Fig. 1, there is shown a laser source ` .
~' 5a- ~
.
- ; , .. . - ,,~, ,,,: . .. , :; - : . - .
1, which may ~onqlst of a carbo~ dioxide laser, h~ving a tunable , outp~t freguency over a wavelength range from 9.473 microns to 10.858 microns. A beam la is emitted by ~he laser and is ,1 optionally focused by a lens 2 onto one sid~ of a running ~ibcr ~, 3, pacising over a pair of tensiioning rollers 4 and 5. A beam , 8t~p 6 ~ 9 provided to intercept that portlon of the beam which ¦1 ~ypasses the flber 3.
¦ ~ The fiber 3 which is to be textured is supplied from !! a fiber supply package 7 and driven over rollers 4 and 5 and is ~ eventually taken up in a fiber taXe-up 8. During the oourse of ', travel of the fiber 3 o~er the rollers 4 and 5, the fiber 3 may .
' be elongated.
j~ . . . . .. . . . .. .. . .
; l In one specific example in which the effect of the differential gradient heating by the tuned laser arrangement - 1 according to the present invention was measured, the fiber ~' I tested was 297 denier saran monofilament, imparted with an . ~ nlon~ation o~ approxit~ately 5~ and travelling across the laser - 1I Leam la at a speed of about 45 feet/min. Saran monofilament has an ab~orption band in the area o~ 9.6 microns so that the ¦ laser wa3 tuned to one o~ its tunable requency lines at , 1 9.586 microns and ru~ at moderate ~ower without using the lc~3 2 to focu~ the bea~.
~ ll Vpon leavinq the last go~et, the saran monofilament - 2S - exhibited helical characteristic~. The filament was placed in ¦ ~o~llny water for ap~roximately 30 seconds to allow or ¦
¦ approximately 4~ 3hrinkage to occur in the non-treated regions I ~
o~ ~hR fllamen~. The helix th~n exhibited a~much smaller, ~;
¦ sliqhtly v3rying radius o~ ~ur~ature with reversals o~ the I hellx.
.'.' , ' ' _~ .
,., . I . , ' ~ ' ,, ' . .
.
.: . . .:: . ~. ~ . . -1~ ( I
~ 5 ', !
Wlth respect to the irradiatlon oE the flber ltself ~y th~ laser ~am la, Fig. 2 shows the fiber 3 in , enlarged cross-section, an irradiated portion 3a o~ which is , directly impinged upon by the laser beam la. With the 5 , frequenry of the laser beam la being tuned to an absorption ` band of the fiber 3, the irradiated portion 3a will rapidly 'I a~sorb ~he energy from the beam la by molecular resonance ¦ effects. Since the shaded side is not directly ixradiated by Il the beam la, a differential thermal gradient is created within 10 L the fi~er 3, 50 that the fiber 3 is asymmetrically heated and a textured fiber is obtained. The focusing lens 2 adjusts the 1 diameter of the beam la in the zone through which the fiber 3 - I pa3ses to approximately the size of the fiber 3 so as to make . . I the energy coupling ~ore efficient.
15 jl 0~ course, the particular laser employed will ; , depend upon the ahsorption band of the yarn to be treated and the present invention is not exclusively limited to the above-!¦ referred to C02 laser This laser has been descri~ed in ¦i ~onnection with the exemplary fiber saran monofilament since the laser output frequency and the absorption band ! cha~acteristics of this particular flber can be matched when the laser is a C02 laser. For other ~ibers having different absorption band characteristics, tha laser will be chosen so that it can be tuned to the absorption band of the fiber 25 being treatud.
As ha~ been descrlbea above, in accordance with ¦ the present invention, a fiber such as a filament of a yarn can . ¦ be textured by a3ymmeeri~ heating by laser irradiation of one ¦ slde of the fiber with the laser being tuned so that $ts ¦wav~length matcheg an absorptlon band of the ~iber. The texeure I ¦typically produced by such asymmetric heating la a helix. The 7 ~
, 11 . " . ~ , . I
. , ~ LS~
. ., ¦1 actual physical parameters o the helix, namely, the diameter and pitch can be calculated on the basis of known factors. The , diameter of the helix is basically influenced by filament i diameter, the elDngation set into the filament by the laser, 5 1 and shrinkage induced by hea~, steam, or even a dye b~th for the yarn. Cons$dering the cross-sectional diameter of the ~iIament to be df and the elongation along the outer edge of the filament having the largest radius of curvature to be the value x and the shrinkage along the inner edge of the filament I ha~in~ the smallest radius of curvature to be the value y, then I the diameter of the helix DheliX can be calculated to be:
-- Ij -~,i Dhel ix d~
'. , 15. ~ i~
1 ' ` 'I'i , ' `
J Il ~he pitch of the helix ~namely the number of turns ¦ per inch) is influenced by the twist of the feeder yarn/filament prior to treatment. If the feedes filament~yarn has no twist tand no twist is induced during the heating process, ehen the ao relaxed hel~x will assume a limiting pitch, namely a unit length of coil/d~ ~ number of turns/unit lengtb. This evaluatioj can bs modified if the filament~yarn has been twisted prior to trcatment. The effect is to modulate the ideal halix in such 3 ' ; ~anner as to cause the helix diameter to vary and also to cause ~, 25 ~ I the helix directlon to re~erse itself. This reversal of the ~elix i~parts further texturing to the fiber so that i~ can be 9~en that a combination of factors may be added to the basic ~i3ym~etxic heating in accordance with ehe pra3ent invention , to obtain a textured f'ber.
. . '.
~ a - ~
. . l .. . .... - ., . ,. ... , . - ... , , . . ... . - . :-.
-' 'I I
5~
! The yarn speed, namely the speed at whlch the yarn Il travels through the zone of the lasQr beam, ls a function of ! the power density of the laser that can be provided at the irradiation zone. The length of ti~e during which the yarn traverses this irr~diation zon~ is orders of magnitude larger i than the time required to couple the energy into the yarn, .I nam,ely, on ~he order of 10-1 seconds. It can be readily ¦i apprecia~ed~ accordingly, that ~y matching the absorption band il to thê wavelength of the laser, a very efficient coupling of thq energy in the laser beam to the fiber is obtained to impart the desired asymmetric heating to the fiber and achieve the aesired textured fiber. I ..
~¦. It will ~e appreciated that the fibers sultable I! for purposes of this invention are thermoplastic polymeric materials. Preferred are the fibers of textile yarns which - possess a finite but real elongation and which are susceptible !~ to boiling water shrinkage, e.g., on the order of at least 4~.
¦ 2xemplary of such materials are nylon, polyethylene, pDlyvinyl -- j chloride, polypropylene, acrylic resins such as the poiyacrylonitriles, polyesters, and ~he like.
¦ While I have shown and described several e~bodiments . ln accordance with the present invention, it is understood that ¦ the same is not limited thereto but is susceptible of numerous . ¦ changes and modifications as known to a person skilled in the I art, and ~ therefore do not wish to be limited to the details ~hown and de~cribed herein bu~ intend to cover all such changes I ~d moaifications as are obviou to one of ordinary skill in ¦ t~ ~rt-.
:.
Claims (8)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. In a method of texturing polymeric fibers including filaments or yarns, in which a beam of electromagnetic energy is caused to impinge upon a fiber, the improvement wherein the beam of electromagnetic energy employed is a laser beam having a wavelength falling within an absorption band of the poly-meric material of said fiber and the beam is caused to impinge upon a side of said fiber so that the polymeric material of the fiber beneath the irradiated surface of the fiber upon which the beam is directed effectively shades the remaining non-irradiated surface of the fiber, whereby a differential thermal gradient is created within the fiber from the irradiated surface to the non-irradiated surface.
2. A method of texturing polymeric fibers including filaments or yarns, comprising the step of:
directing, upon a side of a fiber of a polymeric material to be textured, a laser beam, the wavelength of which falls within an absorption band of the polymeric material of said fiber, said beam being directed at said fiber so that the polymeric material of the fiber beneath the irradiated surface of the fiber upon which the beam is directed effectively shades the remaining non-irradiated surface of the fiber, whereby a differential thermal gradient is created within the fiber from the irradiated surface to the non-irradiated surface.
directing, upon a side of a fiber of a polymeric material to be textured, a laser beam, the wavelength of which falls within an absorption band of the polymeric material of said fiber, said beam being directed at said fiber so that the polymeric material of the fiber beneath the irradiated surface of the fiber upon which the beam is directed effectively shades the remaining non-irradiated surface of the fiber, whereby a differential thermal gradient is created within the fiber from the irradiated surface to the non-irradiated surface.
3. A method according to claim 2, further comprising the step of:
focusing said beam upon the irradiated surface of said fiber to a spot approximating the width of said fiber.
focusing said beam upon the irradiated surface of said fiber to a spot approximating the width of said fiber.
4. The method according to claim 2, further comprising the step of elongating said fiber while directing said beam upon the fiber.
5. The method according to claim 4, further comprising the step of:
focusing said beam upon the irradiated surface of said fiber to a spot approximating the width of said fiber.
focusing said beam upon the irradiated surface of said fiber to a spot approximating the width of said fiber.
6. The method according to claim 2, wherein said directing step comprises irradiating said fiber with the laser beam and adjusting the frequency of said beam so that the wavelength of said beam falls within an absorption band of said fiber.
7. The method according to claim 2, further comprising the step of:
moving said fiber through the zone in which said beam of electromagnetic energy is caused to impinge upon said fiber so that successive portions of a side of said fiber are irradiated by said beam.
moving said fiber through the zone in which said beam of electromagnetic energy is caused to impinge upon said fiber so that successive portions of a side of said fiber are irradiated by said beam.
8. The method according to claim 2, wherein said poly-meric material is nylon, polyethylene, polyvinylchloride, polypropylene, acrylic resin, saran or polyester.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US78373677A | 1977-04-01 | 1977-04-01 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1080457A true CA1080457A (en) | 1980-07-01 |
Family
ID=25130234
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA299,628A Expired CA1080457A (en) | 1977-04-01 | 1978-03-23 | Fiber texturing method |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1080457A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2151515A1 (en) * | 2008-08-05 | 2010-02-10 | Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. | Method for texturizing polymeric monofilaments |
-
1978
- 1978-03-23 CA CA299,628A patent/CA1080457A/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2151515A1 (en) * | 2008-08-05 | 2010-02-10 | Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. | Method for texturizing polymeric monofilaments |
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