CA2183776A1 - Crimped pigmented conjugate fibers - Google Patents
Crimped pigmented conjugate fibersInfo
- Publication number
- CA2183776A1 CA2183776A1 CA 2183776 CA2183776A CA2183776A1 CA 2183776 A1 CA2183776 A1 CA 2183776A1 CA 2183776 CA2183776 CA 2183776 CA 2183776 A CA2183776 A CA 2183776A CA 2183776 A1 CA2183776 A1 CA 2183776A1
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- pigments
- conjugate fiber
- pigment
- crimped
- composition
- Prior art date
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- Nonwoven Fabrics (AREA)
Abstract
There is provided in accordance with the present invention a helically crimped, pigmented conjugate fiber and a nonwoven fabric containing the conjugate fiber. The conjugate fiber contains at least a first composition and a second composition, and the first and second compositions contain different thermoplastic polymer having different solidification periods, wherein one of the two compositions contains a pigment or the two compositions contain disparate amounts of a pigment.
Additionally provided is a process for simultaneously pigmenting a conjugate fiber and controlling the degree of latent crimpability in the conjugate fiber.
Additionally provided is a process for simultaneously pigmenting a conjugate fiber and controlling the degree of latent crimpability in the conjugate fiber.
Description
218~775 C~IlIPED pT~V~nr~r CONJUGATE FIBER8 s BACKGROUND OF THE INVENTION
The present invention is related to crimped, pigmented con~ugate fibers and - ~ Yel~ fabrics p ~-Iu- éd theref rom .
~ vel~ fabrics containing crimped colljuyate fibers 10 or f~l L~ provide desirable flln~-~ioni~l and textural properties, including soft hand, flPYihi 1 ~ty, drape and porosity, when ~ ed to = ~._.l fabrics containing uncrimped f ibers . Crimped ~ J u~ate f ibers or f i 1 i ts suitable for n~,l. .ve.l fabrics contain at least two lS polymeric ~ L compositions which are aLLall~ed in substantially distinct soc tinn~ across the ;LoS5 se_Lion along the length of the fibers or filaments, and they can be th~ lly~ ~hom;oi~lly or ~nici~lly crimped.
Nonwoven fabrics containing thermally crimped conjugate 20 fibers are ~ clofiocl~ for example, in U.S. Patents 3,423,266 to Davies et al.; 3,595,731 to Davies et al.
and 5,382,400 to Pike et al. In general, thor~-lly crimped C~ ate f ibers are ~L ,duced by heat treating cvll~u~a~e fibers having latent cri _ hi 1 ity. Such 2s cullju~<lte fibers having latent cri -hi 1 ity are formed when the ~ L polymers of the fibers have different shrinkage and/or crystallization reD~ es to a heat LL~ai Typically, however, it is difficult to control the 30 level of crimps imparted in the f ibers during the course of a thermal crimping process. If the level of crimps is too high, interfiber entanglements among the fibers become too f irm and irregular . Such overly crimped fibers produce noll..~vell fabrics exhibiting non-uniform :~5 fiber coverage and caliper. In contrast, if the level of crimps is too low, the resulting n~ vèn webs may not provide desired textural properties . U. S. Patent 5,382,400 to Pike et al. teaches a method to ~V~LC
~ ~ 3~^7~
this crimp level control problem. Although the patent teaches a method for imparting different levels of crimps by applying different activating t~ aLuL~s, there remains a need for additional means that can be used in s conjunction with the t~ aL~-: control method or used separately to control the level of crimps in c;~lljuyate f ibers .
8~aRY OF T~
o The present invention provides a h~l ~cnl ly crimped, pigmented multi~ t C~l-juyate fiber containing at least a first composition and a second composition. The first composition has a first 1 , lnqtic polymer and the second composition has a second t~ , lnf~tic polymer which has a different solidification period than the f irst thermoplastic polymer, wherein one of the f irst and second compositions contains an effective amount of a pigment. The invention additionally provides a helically crimped, pigmented multit L ~ Juyate fiber having at least two, ~ compositions that have different amounts of a pigment. The term "solidification period"
as used herein indicates the amount of time that a melt spun polymer composition that exits the fiber-forming spinneret takes to solidify in a given con~ugate fiber pro~ t~tit~n set up, more specifically g-lt~nt hin~ and drawing set up.
The invention also provides a process for simult~nt~o~qly pigmenting and controlling the level of latent crimpability of a crimpable multi~: L
conjugate fiber, wherein the conjugate fiber contains at least a first polymer composition and a second polymer composition, and the first composition polymer has a faster solidification period than the second composition polymer. The steps of the process include adding disparate amounts of a pigment in the f irst and second 218377~
composltions and ~pinning a conjugate fiber having a crimpable configuration from the compositions, wherein the process increases the level of latent crimpability when a higher amount of the pigment is added in the first s composition and decreases the level of latent cri hi l; ty when a hiqher amount of the pigment is added in the second composition. The term " crimpable configuration" as used herein indicatefi a cross-sectional configuration of a Cv~ l e fiber that does 10 not impose g~ LLlcal or configurational constraints in the fibers to prevent the formation of crimps when the latent crimpability is activated. For example, a cv--~èl-LLlc sheath-core configuration is not a crimpable configuration since the cv..ve..LLical ~y ~Ly of the 15 ,:LV5S ~ irnl: of the _ t polymers does not readily allow the fibers to form th~ l ly activated crimps.
Additionally, the terms "web" and "fabric" are used interrhAn~eAhly~ unless otherwise indicated, and the terms " f ibers " and ' ~ f; 1 " are used 20 interrh~nge~hly~ unless otherwise indicated.
BRIEF }~ ,_ OF T}~S ~
Figure 1 illstrates a ~rocess for producing the 5 pigmented v u..~ u~te f iber of the present invnetion and a . fabric containing the conjugate fiber.
TT ~ ,, _ OF Tl~ ln ~
The ~v..J ~ e f ibers of the present invention may 30 contain more than two polymer ~ L . However, for illustration purposes, the present invention is described with two . L (bi~ -nt) conjugate fibers.
The present invention provides a crimped cv..; u~lte fiber that contains a crimp-in~ r;n~ pigment (pigment) in 3s one of the two - L composition or contains ~1%3~7B
disparate amounts of a pigment in the two compositions.
Additionally, the present invention provides a method for simultAn~o~ y pigmenting and controlling the level of crimps in cu..; u~te f ibers .
S The vv~juyate fibers of the present invention have a crimpable configuration. Suitable configurations include side-by-side conf igurations and eccentric sheath-core configurations. In addition, the polymer c of the conjugate f ibers contain two - ~ polymers that o are s~l ec~ from semi-crystalline and crystalline ~h~ , lA~:tiC polymers which have different sol; ~l l f irAtion periods with respect to each other ~Itively~ a fast solidifying and a slow solidifying polymers . It is believed that the solidif ication period is influenced by different parameters inr l~ n~ the melting tr _ a.~u~-it and the rate of crys~Al l; 7ation of the _ polymer. Accordingly, the fast solidifying 1. polymer of the aol.; u~te f iber desirably has a melting point about 10C or higher, more desirably about 20C or higher, most desirably about 30C or higher, than the slow solidifying ~ polymer. However, the two ~ polymers may have similar melting points if their crystAl l; ~s~tion rates are measurably different.
In aavv~-la~ce with the present invention, one of the two polymer ~ _ L~ contains an effective amount of a pigment. The pigment is added to the l.
composition not only to impart desired color to the v v~ ate f ibers but also to control the degree of latent cr; -hi l ity. In general, a high degree of latent ~-r; -h; 1 ;t-y provides a high level of crimps when the fibérs are exposed to a given latent cr; -h;l;ty activating temperature. Accordingly, the level of crimps in the conjugate f iber of the present invention can be controlled by regulating the degree of latent 35 cri -hi l ity with the addition of a pigment. In accordance with the present invention, the level of crimps in conjugate fibers having latent crimpability can be increased by adding an effective amount of a pigment only in the fast solidifying polymer -~, and the 5 level of crimps can be decreased by adding an effective amount of a pigment only in the slow solidifying polymer ^ t. Desirably, between about 0. 005% and about 2%, more desirably between about 0.01% and about 1%, based on the total weight of the ~ L composition of the cvl.~u~te fiber, of a pigment is added in the polymer composition .
Alternatively, disparate amounts of a pigment can be added to the two polymer ~:~ to control the degree of latent cr; h;l;ty and to pigment the fibers. Por 15 example, when both 1,8 of the culljuy~te fibers contain a pigment, a larger amount of the pigment can be added to the fast solidifying polymer ~ ent to increase the degree of latent cr; -h;l;ty, and a larger amount of the pigment can be added to the slow 20 solidifying polymer ~ to de.L~ ase the degree of latent cr; _ h; l; ty. In ~c- VL~ l e with the present invention, the L composition containing the larger amount of the pigment contains, desirably, at least about 25% more than the other t 25composition.
In addition, more than one pigment can be added to the ~_ ~ compositions to control the degree of latent crimpability. For example, when an equal amount of a pigment is added to the ~ L compositions, a 30 second pigment can be added to one of the ~ L
compositions to control the degree of latent cr; -h; 1 i ty.
Suitable crimp-;n~ ;n~ pigments for the present invention include organic and inorganic pigments known to 3s be suitable for crystalline and semi-crystalline 218377~
thermoplastic polymers. Desir~bly, suitable pigments have an average particle size equal to or less than about o . 5 ~m, more desirably equal to or less than about 0 . 3 ~m. The lower limit of the particle size is not critical s provided that the pigment particles are not as small as to lose their color. Exemplary suitable organic pigments include monoazo pigments, e.g., hanasa yellows, toluidine reds, naphthol reds, tartrazine lake, ponr-nont red 2B
and peLIl.a~ .L yellow FGL; benz1mi~loA7~ no pigments;
lo disazo pigments, e.g., diarylide yellows, diarylide oranges and tliAn~ 11ne red; disazo con~oncation pigments; quinacridone pigments; ~ yAn7~no violet; vat pigments, e.g., flavanthrone yellow, dllUI~ ~I yLlmidine yellow, pyranthrone orange, perinone orange, brominated 15 anthanthrone ordnge, brominated pyranthrone, anthramide orange, illda..U.Lol~e blue, isoviold,.~ ..e violet;
perelene r~ Ls; thiQ~ntl~qo pigments; phthalocyanine pigments, e.g., copper phthalocyanine blue;
tetrachloro~in~lolinone pigments; and mixtures thereof.
20 Inorganic pigments suitable for the present invention includes metal oxides, e.g., "1~ n oxide, lead oxide, iron oxide, titanium dioxide, antimony oxide and calcium oxide; metal particles; mineral particles and cadmium pigments, e.g., cadmium sulfide. Of these suitable 25 pigments, particularly suitable for the present invention are organic pigments including phthalocyanine pigments, disazo pi~ , disazo c~n~lon~ation pi~; L6 quinacridone pigments and mixtures thereof.
Crystalline and semi-crystalline polymers suitable 30 for the present invention include polyolefins, polyamides, polyesters, vinyl acetate-based polymers, and blends and copolymers thereof . Useful polyolef ins include polyethylenes, e.g., high density polyethylene, medium density polyethylene, low density polyethylene and 35 linear low density polyet~ylene; polypropylenes, e.g., - . 2~8377~
isotactic polypropylene an~l syndiotactic polypropylene;
polybutylenes, e.g., poly(l-butene) and poly(2-butene);
polypentenes, e.g., poly(2-pentene), and poly(4-methyl-1-pentene); and blends thereof. Useful polyole~in s copolymers include ethylene-propylene copolymers. Useful vinyl acetate-based polymers include polyvinyl acetate;
ethylene-vinyl acetate; saponified polyvinyl acetate, i . e ., polyvinyl alcohol ; ethylene-vinyl alcohol and blends thereof. Useful polyamides include nylon 6, nylon lO 6/6, nylon 10, nylon 4/6, nylon 10/10, nylon 12, hydrophilic polyamide copolymers such as caprolactam and alkylene oxide diamine, e.g., ethylene oxide diamine, copolymers and h. ylene A-lirAmide and alkylene oxide copolymers, and blends thereof. Useful polyestèrs 5 include polyethylene terephthalate, polybutylene terephthalate, and blend6 thereof. Of these, particularly suitable polymer combinations include polypropylene/polyethylene, e.g., isotactic polypropylene/high den&ity polyethylene and isotactic 20 polypropylene/linear low density polyethylene;
nylon/polyproplene, e.g., nylon 6/isotactic polypropylene and nylon 6, 6/isotactic polypropylene;
nylon/polyethylene, e.g., nylon 6/high or linear low density polyethylene and nylon 6, 6/high or linear low 2s density polyethylene; polyester/propylene, e.g., polyethylene terephthalate/isotactic polypropylene and polybutylene terephthalate/isotactic polypropylene;
polyester/polyethylene, e.g., polyethylene terephthalate /high or linear low density polyethylene and polybutylene 30 terephthalate/high or linear low density polyethylene.
As stated above, the latent crimpability of the conjugate fibers is activated by a heat treatment. The heat treatment heats the fibers to a t~ ULe equal to or higher than the temperature at which the slow 3~; solidifying ~ t polymer star~s to resume its 218377~
crystallization but below the melting point of the loweDt melting ~. t polymer . ~r~n~ i ng on the polymers selected for the conjugate fibers, the heat ~Lea;
temperature will vary widely. However, the heat 5 treatment in general needs to raise the tA, ~I~UL~a of the fibers to about 45C or higher in order to appreciably activate the latent crimp. In general, a higher temperature induces a higher number of crimps in the fiber. The latent crimp6 can be activated before, lo during or after the fibers are deposited or laid to form a n~....~ ven web. ~owever, it is highly desirable to activate the crimps in the fibers before they are deposited to form a nv.._.v~.l web since the crimping process inherently causes shrinkage and dimensional changes that are dif f icult to manage and tend to adversely affect uniformity and fiber coverage of the web. Therefore, it is highly a-lva~ gèous to crimp the c~..lJuy~lte fibers before they are formed into a - J~
web in order to provide a dimensionally stable web that 20 has uniform fiber ;U.~L Je and uniform bulk.
The cvllju~te fibers of the present invention can be oduced by various known ~L.acess~s for producing ~ juy~te fibers, ;n~ 1n~ staple fiber pro~lllrt;rn processes, Dl~ h" l fiber production E,Locesses and 25 meltblown fiber prr,~ rt;On process. of these, particularly suitable ~Locesses for the present invention are ~ ,h-~- -1 f iber procl~lrt ion processes .
A particularly suitable process for the present invention that produces crimped c~,--J u~lte f ibers and 30 n.,... ~vtn fabrics containing thereof is ~ rlo8Dd in U.S.
Patént 5,382,400 to Pike et al. The patent in its entirety is herein in~;uL~L~ted by reference. Turning to Figure 1, there is illUA~LC~ted an exemplary conjugate fiber spunbond nonwoven fabric production process 10 that 35 is particularly suitable for the present invention. A
~3776 pair o~ extruders 12a and 12b separately extrude the , L compositions for the conjugate fibers, in which one of the compositions contains an effective amount of a pigment. The compositions are separately fed into a 5 first hopper 14a and a second hopper 14b, to simultaneously supply molten polymeric compositions to a spinneret 18. Suitable spinnerets for extruding conjugate fibers are well known in the art. Briefly, the spinneret 18 has a housing which contains a spin pack, and the spin lo pack contains a plurality of plates and dies. The plates have a pattern of opPnin~C ~ILLcl~ged to create flow paths for directing the two polymers to the dies that have one or more rows of opDn;ngc~ which are designed in accordance with the desired configuration of the 15 re6ulting conjugate fibers.
me spinneret 18 provides a curtain of conjugate f; 1 ~s or continuous f ibers, and the continuous f ibers are quenched by a quench air blower 20 and develop latent cr; -hi 1 ity. me quenched fibers are then fed to a 20 fiber drawing unit. Any pneumatic fiber drawing unit or aspirator that is known to be suitable for a ~.. h.~l,A
process can be used for the present invention provided that the f iber draw unit is modif ied to utilize heated air, instead of conventionally used ambient air, to draw 25 the fibers. Of these, particularly suitable fiber draw units for the present invention are linear fiber aspirators of the type disclosed in U.S. Patent 3,802,817 to Matsuki et al., which in its entirety is incu.~,La~ed by reference. Briefly, the fiber draw unit 22 ;n~ D~ an 30 elongate verticâl passage through which the f ilaments are drawn by fiber drawing air entering from the side of the p;~ca~e. The drawing air, which is supplied from a ~ ~ssed air source 24, draws the filaments and imparts molecular orientation in the filaments. In accordance 3s with the present invention, the drawing air is heated 2~776 with a temperature adjustable heater in order to simultaneously draw the ~ibers and activate the latent cr; hi 1 ity. The tf Cl~UL~ of the drawing air can be varied to achieve different levels of crimps, as 5 indicated above. In accordance with the present invention, the solidifying periods of the ~_ polymers are detPrminPcl in this fiber ~lo~hinq and drawing environment.
The process line 10 further inrlll~lDc an endless o foraminous forming surface 26 which is placed below the draw unit 22 and is driven by driver rollers 28 and positioned below the fiber draw unit 22. The drawn filaments eYiting the fiber draw unit are generally deposited in isotropical or random fashion onto the 15 forming surface 26 to form a r ~V~:II web of uniform ~h; e~nP~s: and f iber cvv~ ge . The f iber depositing process can be better facilitated by placing a vacuum apparatus 30 directly below the forming surface 26 where the fibers are being deposited. The abv~c desv ibed 20 simultaneous drawing and crimping process is highly useful for producing lofty r~L~ ~ h~ webs that have uniform fiber ~.v~ e and uniform web caliper.
The deposited nv~ v-:n web is then bonded, for example, with a through air bonding process. Generally 2s described, a through air bonder 36 in~ P~ a perforated roller 38, which receives the web, and a hood 40 ~uLLvullding the perforated roller. ~eated air, which is hot enough to melt the lower melting ~ ~ polymer of the cvllJu~clte fiber, is sllrpl ied by the hood 40 to the 30 web through the perforated roller 38. The heated air melts the lower melting polymer and the ~elted polymer forms interfiber bonds tllL~u~llvu~ the web, P~poc;Al ly at the cross-over contact points of the f ibers . Through air bonding processes are particularly suitable for producing 35 a lofty, uniformly bonded spunbond web since these ~ 218377~
processes uniformly effect interfiber bonds without applying significant ' ^c~inq ~La~.,u,e. Alternatively, the llnh- n(l~3 nu.. ~v~. web can be bonded with a ~Al-~n~lDr bonding process . A CA l ~ r bonding process typically 5 utilizes an assembly of twû or more of abuttingly placed heated rolls that form a nip to apply a combination of heat and ~LeS~u. a to melt fuse the f ibers of a web to form bonded regions or points in the web. The bonding rolls may be smooth or contain a pattern of raised bond o points.
As indicated above, the conjugate fibers of the present invention can be controlled to have varying levels of crimps, and thus, the bulk of the nv-- .v~n fabrics containing the cu..juyclte fibers can be adjusted 15 to desirable levels. For example, when a combination of selected : polymers provides an undesirably low level of crimps, a pigment can be added to the fast solidifying composition to simul~An~o~cly increase the crimp level and to pigment the f ibers, and if a 20 combination of selected c 1. polymers provides an overly high level of crimps, a pigment can be added to the slow solidifying composition to decrease the crimp level and to pigment.
In addition to the pigment, the polymer compositions 25 of the coniugate f ibers may contain minor amounts of various additives and fillers that are conventionally used in the pro~ cti~n of fibers and nu-~ ... fabrics.
Useful additives include compatibilizing agents, dyes, optical brighteners, ultraviolet light stabilizers, 30 antistatic agents, lubricants, abrasion resistance ~nhAn--;n~ agentg, nucleating agents and other processing aids .
The 1lvll u v~ fabric or web of the present invention that contains pigmented conjugate fibers having a 35 controlled level of crimps can be used in a wide variety 2183~76 of pLuduuLs. ~ l..uvtl~ f~brics of the present invention that have a high level of crimps and thus have a high bulk and a high poro6ity are, for exalDple, highly suitable for fluid r~-r- ~ ~ L layers of absorbent and 5 personal care articles, e.g., diapers, in~ ontinonce care articles, sanitary napkins and training pants; active agent delivery system, e.g., c- ~ic scrubbing pads and polishing agent applying pads; and filters. Present nu.. .~ fabrics that have a low level of crimps and thus lo a low bulk are, for example, highly suitable for protective 'J~ ~~ r, drapes, wraps and cloth-like outer cover materials for absoLI,~ and personal care articles.
The fQllowing eYamples are provided for illustration ~uL~06es and the invention is not limited thereto.
r ~campl~ 1 (Exl) A 1.5 ounce per square yard t51 g/m ) r.~
bi~ ^ t fiber web was pLvluced in a~u,d~ e with aforementioned U.S. Patent 5,382,400. A linear low density polyethylene tLLDPE), Aspun 6811A, which is available from Dow t'h~ l, was blended with 2 wt% of a 2s Tio2 ~-...c6-.~L~te which had 50 wt~ of Tio2 and 50 wt96 of a polypropylene, and the miYture was fed to a first single screw extruder. The Tio2 used was commercially available conventional Tio2 which has an average particle size of about 0.5 ~Lm. A polypropylene, PD3445, which is 30 available from Exxon, was blended with 2 wt% of the above-described Tio2 ~v~c~ te and with 1 wt96 of a blue pigment. The blue pigment used was SCC 3185, which is available from Standridge Color Corporation, GA. The main ~ contained in SC 3185 are about 1. 4 wt96 vf 3s phthalocyanine blue and about 0. 296 of magenta ~ 18~776 .
quinacridone. The mixture was fed to a second single screw extruder. In this c .rnt polymer combination, polyproyplene is the fast solidifying polymer and LLDPE
is the slow solidifying polymer. The ~LLuded polymers S were spun into round bi~ 1. fibers having a side-by-side conf iguration and a 1:1 weight ratio of the two ~ polymers using a hj- L spinning die, which had a 0 . 6 mm spinhole diameter and a 6 :1 L/D ratio .
The melt t~, ,-LuL~g of the polymers fed into the lo splnnin~ die were kept at 450F (232C), and the spinhole tllL~ uyll~uL rate was o s gram/hole/minute. The bi~ L fibers exiting the spinning die were ~ .- l ed by a flow of air applied at 45 ft3/min/inch (0.5 m3/min/cm) and at a t~ c.tuLæ of 18C. The 5u~n~hing 15 air was applied about 13 cm below the spinneret, and the quenched fibers were drawn in a fiber drawing unit of the type which is described in U.S. Patent 3,802,817 to Matsuki et al . The aspirator was ~T~ i rped with a temperature controlled fiber drawing air source, and the 20 feed air t~ CILUL~ was kept at about 350F (177C).
The ~ d fibers were drawn with the heated feed air to attain a fiber size of about 2.7 denier (3 dtex).
Then, the drawn fibers were deposited onto a foraminous forming surface with the assist of a vacuum flow to form 25 an l~nhrn~rd fiber web. The .~ d fiber webs were bonded by passing the web through a through-air bonder which is equipped with a heated air source. The heated air velocity and the t~ _L~ILUL~ of the heated air was 200 feet/minute (61 m/min) and 272F (133F), 30 respectively. The residence time of the web in the hood was about 1 second.
Based on the fact that the bulk of a ~ .væ.. fabric, in general, ~JLL ~ ingly increases with the increasing level of crimps in the fibers that forms the n-,--.~,vl:n 35 fabric, the bulk of the resulting web was measured and ~183776 compared to study the crimp ;n~ll-~in~ effect of utilizing a pigment. The bulk of the resulting web was measured using a ,Starret-type bulk tester under 0.5 psi (3.4 pKa).
The result i5 shown in Table 1.
s Co~par~tiv- l~campl~ 1 (Cl) Example 1 was repeated except 1 wt% of SCC 3185 was also added ln the LLDPE ~ nt. The result is shown in Table 1 ~ample 2 (Ex2) Example 1 was repeated except 1 wt96 of SCC 3185 was added to the LLDPE ~ , L and not to the polypropylene _, -nt. The conjugate fibers of the ~Lùduced r Jvcn 15 web had a lower level of crimps than the f ibers of Comparative Example 1, and the nul-..Jvcll web had highly u~ uniform Cv~ c and uniformity , ~Gad to the nul...uvcll web of C ~l.ive Example 1. This formation u~ is believe to result from the reduction in 20 the ~.asGI~ce of u~ Limped fibers in the web. The bulk result is shown in Table 1.
Exam~le Bulk ( inch) (mm) Exl 0 . 0825 2 .10 Cl 0 . 0790 2 . 00 Ex2 0 . 077S 1. 97 The abovQ results, which shows that the bulk of the web' of Example 1 is thicker than that of the web of Comparative Example 1, clearly ~ te that adding a pigment in the fast solidifying ~ _ t polymer composition increases the degree of- latent crimpability and thus improves the crimp level of the conjugate fiber.
n addition, Example 2 and Comparative Example _Ltlte that adding a pigment in the 510w solidifying L polymer composition decreases the degree of latent cri hil ity and thus decreases the crimp level of s the conjugate fiber, while improving the fiber coverage and uniformity of the web.
'lhe conjugate fibers can be ~Lvduced to have a controlled level of crimps while pigmenting the fibers and, thus, can be used to produce nv~ v~ fabrics having o different levels of bulk and porosity, textural properties and colors.
Although pref erred : ' ~o~ of the invention have been described herein, it will be understood by those skilled~ in the art that variation~, modifications, and e~uivalents may be made thereto without departing from the spirit of the invention or the scope of the appended c~ :lml~.
The present invention is related to crimped, pigmented con~ugate fibers and - ~ Yel~ fabrics p ~-Iu- éd theref rom .
~ vel~ fabrics containing crimped colljuyate fibers 10 or f~l L~ provide desirable flln~-~ioni~l and textural properties, including soft hand, flPYihi 1 ~ty, drape and porosity, when ~ ed to = ~._.l fabrics containing uncrimped f ibers . Crimped ~ J u~ate f ibers or f i 1 i ts suitable for n~,l. .ve.l fabrics contain at least two lS polymeric ~ L compositions which are aLLall~ed in substantially distinct soc tinn~ across the ;LoS5 se_Lion along the length of the fibers or filaments, and they can be th~ lly~ ~hom;oi~lly or ~nici~lly crimped.
Nonwoven fabrics containing thermally crimped conjugate 20 fibers are ~ clofiocl~ for example, in U.S. Patents 3,423,266 to Davies et al.; 3,595,731 to Davies et al.
and 5,382,400 to Pike et al. In general, thor~-lly crimped C~ ate f ibers are ~L ,duced by heat treating cvll~u~a~e fibers having latent cri _ hi 1 ity. Such 2s cullju~<lte fibers having latent cri -hi 1 ity are formed when the ~ L polymers of the fibers have different shrinkage and/or crystallization reD~ es to a heat LL~ai Typically, however, it is difficult to control the 30 level of crimps imparted in the f ibers during the course of a thermal crimping process. If the level of crimps is too high, interfiber entanglements among the fibers become too f irm and irregular . Such overly crimped fibers produce noll..~vell fabrics exhibiting non-uniform :~5 fiber coverage and caliper. In contrast, if the level of crimps is too low, the resulting n~ vèn webs may not provide desired textural properties . U. S. Patent 5,382,400 to Pike et al. teaches a method to ~V~LC
~ ~ 3~^7~
this crimp level control problem. Although the patent teaches a method for imparting different levels of crimps by applying different activating t~ aLuL~s, there remains a need for additional means that can be used in s conjunction with the t~ aL~-: control method or used separately to control the level of crimps in c;~lljuyate f ibers .
8~aRY OF T~
o The present invention provides a h~l ~cnl ly crimped, pigmented multi~ t C~l-juyate fiber containing at least a first composition and a second composition. The first composition has a first 1 , lnqtic polymer and the second composition has a second t~ , lnf~tic polymer which has a different solidification period than the f irst thermoplastic polymer, wherein one of the f irst and second compositions contains an effective amount of a pigment. The invention additionally provides a helically crimped, pigmented multit L ~ Juyate fiber having at least two, ~ compositions that have different amounts of a pigment. The term "solidification period"
as used herein indicates the amount of time that a melt spun polymer composition that exits the fiber-forming spinneret takes to solidify in a given con~ugate fiber pro~ t~tit~n set up, more specifically g-lt~nt hin~ and drawing set up.
The invention also provides a process for simult~nt~o~qly pigmenting and controlling the level of latent crimpability of a crimpable multi~: L
conjugate fiber, wherein the conjugate fiber contains at least a first polymer composition and a second polymer composition, and the first composition polymer has a faster solidification period than the second composition polymer. The steps of the process include adding disparate amounts of a pigment in the f irst and second 218377~
composltions and ~pinning a conjugate fiber having a crimpable configuration from the compositions, wherein the process increases the level of latent crimpability when a higher amount of the pigment is added in the first s composition and decreases the level of latent cri hi l; ty when a hiqher amount of the pigment is added in the second composition. The term " crimpable configuration" as used herein indicatefi a cross-sectional configuration of a Cv~ l e fiber that does 10 not impose g~ LLlcal or configurational constraints in the fibers to prevent the formation of crimps when the latent crimpability is activated. For example, a cv--~èl-LLlc sheath-core configuration is not a crimpable configuration since the cv..ve..LLical ~y ~Ly of the 15 ,:LV5S ~ irnl: of the _ t polymers does not readily allow the fibers to form th~ l ly activated crimps.
Additionally, the terms "web" and "fabric" are used interrhAn~eAhly~ unless otherwise indicated, and the terms " f ibers " and ' ~ f; 1 " are used 20 interrh~nge~hly~ unless otherwise indicated.
BRIEF }~ ,_ OF T}~S ~
Figure 1 illstrates a ~rocess for producing the 5 pigmented v u..~ u~te f iber of the present invnetion and a . fabric containing the conjugate fiber.
TT ~ ,, _ OF Tl~ ln ~
The ~v..J ~ e f ibers of the present invention may 30 contain more than two polymer ~ L . However, for illustration purposes, the present invention is described with two . L (bi~ -nt) conjugate fibers.
The present invention provides a crimped cv..; u~lte fiber that contains a crimp-in~ r;n~ pigment (pigment) in 3s one of the two - L composition or contains ~1%3~7B
disparate amounts of a pigment in the two compositions.
Additionally, the present invention provides a method for simultAn~o~ y pigmenting and controlling the level of crimps in cu..; u~te f ibers .
S The vv~juyate fibers of the present invention have a crimpable configuration. Suitable configurations include side-by-side conf igurations and eccentric sheath-core configurations. In addition, the polymer c of the conjugate f ibers contain two - ~ polymers that o are s~l ec~ from semi-crystalline and crystalline ~h~ , lA~:tiC polymers which have different sol; ~l l f irAtion periods with respect to each other ~Itively~ a fast solidifying and a slow solidifying polymers . It is believed that the solidif ication period is influenced by different parameters inr l~ n~ the melting tr _ a.~u~-it and the rate of crys~Al l; 7ation of the _ polymer. Accordingly, the fast solidifying 1. polymer of the aol.; u~te f iber desirably has a melting point about 10C or higher, more desirably about 20C or higher, most desirably about 30C or higher, than the slow solidifying ~ polymer. However, the two ~ polymers may have similar melting points if their crystAl l; ~s~tion rates are measurably different.
In aavv~-la~ce with the present invention, one of the two polymer ~ _ L~ contains an effective amount of a pigment. The pigment is added to the l.
composition not only to impart desired color to the v v~ ate f ibers but also to control the degree of latent cr; -hi l ity. In general, a high degree of latent ~-r; -h; 1 ;t-y provides a high level of crimps when the fibérs are exposed to a given latent cr; -h;l;ty activating temperature. Accordingly, the level of crimps in the conjugate f iber of the present invention can be controlled by regulating the degree of latent 35 cri -hi l ity with the addition of a pigment. In accordance with the present invention, the level of crimps in conjugate fibers having latent crimpability can be increased by adding an effective amount of a pigment only in the fast solidifying polymer -~, and the 5 level of crimps can be decreased by adding an effective amount of a pigment only in the slow solidifying polymer ^ t. Desirably, between about 0. 005% and about 2%, more desirably between about 0.01% and about 1%, based on the total weight of the ~ L composition of the cvl.~u~te fiber, of a pigment is added in the polymer composition .
Alternatively, disparate amounts of a pigment can be added to the two polymer ~:~ to control the degree of latent cr; h;l;ty and to pigment the fibers. Por 15 example, when both 1,8 of the culljuy~te fibers contain a pigment, a larger amount of the pigment can be added to the fast solidifying polymer ~ ent to increase the degree of latent cr; -h;l;ty, and a larger amount of the pigment can be added to the slow 20 solidifying polymer ~ to de.L~ ase the degree of latent cr; _ h; l; ty. In ~c- VL~ l e with the present invention, the L composition containing the larger amount of the pigment contains, desirably, at least about 25% more than the other t 25composition.
In addition, more than one pigment can be added to the ~_ ~ compositions to control the degree of latent crimpability. For example, when an equal amount of a pigment is added to the ~ L compositions, a 30 second pigment can be added to one of the ~ L
compositions to control the degree of latent cr; -h; 1 i ty.
Suitable crimp-;n~ ;n~ pigments for the present invention include organic and inorganic pigments known to 3s be suitable for crystalline and semi-crystalline 218377~
thermoplastic polymers. Desir~bly, suitable pigments have an average particle size equal to or less than about o . 5 ~m, more desirably equal to or less than about 0 . 3 ~m. The lower limit of the particle size is not critical s provided that the pigment particles are not as small as to lose their color. Exemplary suitable organic pigments include monoazo pigments, e.g., hanasa yellows, toluidine reds, naphthol reds, tartrazine lake, ponr-nont red 2B
and peLIl.a~ .L yellow FGL; benz1mi~loA7~ no pigments;
lo disazo pigments, e.g., diarylide yellows, diarylide oranges and tliAn~ 11ne red; disazo con~oncation pigments; quinacridone pigments; ~ yAn7~no violet; vat pigments, e.g., flavanthrone yellow, dllUI~ ~I yLlmidine yellow, pyranthrone orange, perinone orange, brominated 15 anthanthrone ordnge, brominated pyranthrone, anthramide orange, illda..U.Lol~e blue, isoviold,.~ ..e violet;
perelene r~ Ls; thiQ~ntl~qo pigments; phthalocyanine pigments, e.g., copper phthalocyanine blue;
tetrachloro~in~lolinone pigments; and mixtures thereof.
20 Inorganic pigments suitable for the present invention includes metal oxides, e.g., "1~ n oxide, lead oxide, iron oxide, titanium dioxide, antimony oxide and calcium oxide; metal particles; mineral particles and cadmium pigments, e.g., cadmium sulfide. Of these suitable 25 pigments, particularly suitable for the present invention are organic pigments including phthalocyanine pigments, disazo pi~ , disazo c~n~lon~ation pi~; L6 quinacridone pigments and mixtures thereof.
Crystalline and semi-crystalline polymers suitable 30 for the present invention include polyolefins, polyamides, polyesters, vinyl acetate-based polymers, and blends and copolymers thereof . Useful polyolef ins include polyethylenes, e.g., high density polyethylene, medium density polyethylene, low density polyethylene and 35 linear low density polyet~ylene; polypropylenes, e.g., - . 2~8377~
isotactic polypropylene an~l syndiotactic polypropylene;
polybutylenes, e.g., poly(l-butene) and poly(2-butene);
polypentenes, e.g., poly(2-pentene), and poly(4-methyl-1-pentene); and blends thereof. Useful polyole~in s copolymers include ethylene-propylene copolymers. Useful vinyl acetate-based polymers include polyvinyl acetate;
ethylene-vinyl acetate; saponified polyvinyl acetate, i . e ., polyvinyl alcohol ; ethylene-vinyl alcohol and blends thereof. Useful polyamides include nylon 6, nylon lO 6/6, nylon 10, nylon 4/6, nylon 10/10, nylon 12, hydrophilic polyamide copolymers such as caprolactam and alkylene oxide diamine, e.g., ethylene oxide diamine, copolymers and h. ylene A-lirAmide and alkylene oxide copolymers, and blends thereof. Useful polyestèrs 5 include polyethylene terephthalate, polybutylene terephthalate, and blend6 thereof. Of these, particularly suitable polymer combinations include polypropylene/polyethylene, e.g., isotactic polypropylene/high den&ity polyethylene and isotactic 20 polypropylene/linear low density polyethylene;
nylon/polyproplene, e.g., nylon 6/isotactic polypropylene and nylon 6, 6/isotactic polypropylene;
nylon/polyethylene, e.g., nylon 6/high or linear low density polyethylene and nylon 6, 6/high or linear low 2s density polyethylene; polyester/propylene, e.g., polyethylene terephthalate/isotactic polypropylene and polybutylene terephthalate/isotactic polypropylene;
polyester/polyethylene, e.g., polyethylene terephthalate /high or linear low density polyethylene and polybutylene 30 terephthalate/high or linear low density polyethylene.
As stated above, the latent crimpability of the conjugate fibers is activated by a heat treatment. The heat treatment heats the fibers to a t~ ULe equal to or higher than the temperature at which the slow 3~; solidifying ~ t polymer star~s to resume its 218377~
crystallization but below the melting point of the loweDt melting ~. t polymer . ~r~n~ i ng on the polymers selected for the conjugate fibers, the heat ~Lea;
temperature will vary widely. However, the heat 5 treatment in general needs to raise the tA, ~I~UL~a of the fibers to about 45C or higher in order to appreciably activate the latent crimp. In general, a higher temperature induces a higher number of crimps in the fiber. The latent crimp6 can be activated before, lo during or after the fibers are deposited or laid to form a n~....~ ven web. ~owever, it is highly desirable to activate the crimps in the fibers before they are deposited to form a nv.._.v~.l web since the crimping process inherently causes shrinkage and dimensional changes that are dif f icult to manage and tend to adversely affect uniformity and fiber coverage of the web. Therefore, it is highly a-lva~ gèous to crimp the c~..lJuy~lte fibers before they are formed into a - J~
web in order to provide a dimensionally stable web that 20 has uniform fiber ;U.~L Je and uniform bulk.
The cvllju~te fibers of the present invention can be oduced by various known ~L.acess~s for producing ~ juy~te fibers, ;n~ 1n~ staple fiber pro~lllrt;rn processes, Dl~ h" l fiber production E,Locesses and 25 meltblown fiber prr,~ rt;On process. of these, particularly suitable ~Locesses for the present invention are ~ ,h-~- -1 f iber procl~lrt ion processes .
A particularly suitable process for the present invention that produces crimped c~,--J u~lte f ibers and 30 n.,... ~vtn fabrics containing thereof is ~ rlo8Dd in U.S.
Patént 5,382,400 to Pike et al. The patent in its entirety is herein in~;uL~L~ted by reference. Turning to Figure 1, there is illUA~LC~ted an exemplary conjugate fiber spunbond nonwoven fabric production process 10 that 35 is particularly suitable for the present invention. A
~3776 pair o~ extruders 12a and 12b separately extrude the , L compositions for the conjugate fibers, in which one of the compositions contains an effective amount of a pigment. The compositions are separately fed into a 5 first hopper 14a and a second hopper 14b, to simultaneously supply molten polymeric compositions to a spinneret 18. Suitable spinnerets for extruding conjugate fibers are well known in the art. Briefly, the spinneret 18 has a housing which contains a spin pack, and the spin lo pack contains a plurality of plates and dies. The plates have a pattern of opPnin~C ~ILLcl~ged to create flow paths for directing the two polymers to the dies that have one or more rows of opDn;ngc~ which are designed in accordance with the desired configuration of the 15 re6ulting conjugate fibers.
me spinneret 18 provides a curtain of conjugate f; 1 ~s or continuous f ibers, and the continuous f ibers are quenched by a quench air blower 20 and develop latent cr; -hi 1 ity. me quenched fibers are then fed to a 20 fiber drawing unit. Any pneumatic fiber drawing unit or aspirator that is known to be suitable for a ~.. h.~l,A
process can be used for the present invention provided that the f iber draw unit is modif ied to utilize heated air, instead of conventionally used ambient air, to draw 25 the fibers. Of these, particularly suitable fiber draw units for the present invention are linear fiber aspirators of the type disclosed in U.S. Patent 3,802,817 to Matsuki et al., which in its entirety is incu.~,La~ed by reference. Briefly, the fiber draw unit 22 ;n~ D~ an 30 elongate verticâl passage through which the f ilaments are drawn by fiber drawing air entering from the side of the p;~ca~e. The drawing air, which is supplied from a ~ ~ssed air source 24, draws the filaments and imparts molecular orientation in the filaments. In accordance 3s with the present invention, the drawing air is heated 2~776 with a temperature adjustable heater in order to simultaneously draw the ~ibers and activate the latent cr; hi 1 ity. The tf Cl~UL~ of the drawing air can be varied to achieve different levels of crimps, as 5 indicated above. In accordance with the present invention, the solidifying periods of the ~_ polymers are detPrminPcl in this fiber ~lo~hinq and drawing environment.
The process line 10 further inrlll~lDc an endless o foraminous forming surface 26 which is placed below the draw unit 22 and is driven by driver rollers 28 and positioned below the fiber draw unit 22. The drawn filaments eYiting the fiber draw unit are generally deposited in isotropical or random fashion onto the 15 forming surface 26 to form a r ~V~:II web of uniform ~h; e~nP~s: and f iber cvv~ ge . The f iber depositing process can be better facilitated by placing a vacuum apparatus 30 directly below the forming surface 26 where the fibers are being deposited. The abv~c desv ibed 20 simultaneous drawing and crimping process is highly useful for producing lofty r~L~ ~ h~ webs that have uniform fiber ~.v~ e and uniform web caliper.
The deposited nv~ v-:n web is then bonded, for example, with a through air bonding process. Generally 2s described, a through air bonder 36 in~ P~ a perforated roller 38, which receives the web, and a hood 40 ~uLLvullding the perforated roller. ~eated air, which is hot enough to melt the lower melting ~ ~ polymer of the cvllJu~clte fiber, is sllrpl ied by the hood 40 to the 30 web through the perforated roller 38. The heated air melts the lower melting polymer and the ~elted polymer forms interfiber bonds tllL~u~llvu~ the web, P~poc;Al ly at the cross-over contact points of the f ibers . Through air bonding processes are particularly suitable for producing 35 a lofty, uniformly bonded spunbond web since these ~ 218377~
processes uniformly effect interfiber bonds without applying significant ' ^c~inq ~La~.,u,e. Alternatively, the llnh- n(l~3 nu.. ~v~. web can be bonded with a ~Al-~n~lDr bonding process . A CA l ~ r bonding process typically 5 utilizes an assembly of twû or more of abuttingly placed heated rolls that form a nip to apply a combination of heat and ~LeS~u. a to melt fuse the f ibers of a web to form bonded regions or points in the web. The bonding rolls may be smooth or contain a pattern of raised bond o points.
As indicated above, the conjugate fibers of the present invention can be controlled to have varying levels of crimps, and thus, the bulk of the nv-- .v~n fabrics containing the cu..juyclte fibers can be adjusted 15 to desirable levels. For example, when a combination of selected : polymers provides an undesirably low level of crimps, a pigment can be added to the fast solidifying composition to simul~An~o~cly increase the crimp level and to pigment the f ibers, and if a 20 combination of selected c 1. polymers provides an overly high level of crimps, a pigment can be added to the slow solidifying composition to decrease the crimp level and to pigment.
In addition to the pigment, the polymer compositions 25 of the coniugate f ibers may contain minor amounts of various additives and fillers that are conventionally used in the pro~ cti~n of fibers and nu-~ ... fabrics.
Useful additives include compatibilizing agents, dyes, optical brighteners, ultraviolet light stabilizers, 30 antistatic agents, lubricants, abrasion resistance ~nhAn--;n~ agentg, nucleating agents and other processing aids .
The 1lvll u v~ fabric or web of the present invention that contains pigmented conjugate fibers having a 35 controlled level of crimps can be used in a wide variety 2183~76 of pLuduuLs. ~ l..uvtl~ f~brics of the present invention that have a high level of crimps and thus have a high bulk and a high poro6ity are, for exalDple, highly suitable for fluid r~-r- ~ ~ L layers of absorbent and 5 personal care articles, e.g., diapers, in~ ontinonce care articles, sanitary napkins and training pants; active agent delivery system, e.g., c- ~ic scrubbing pads and polishing agent applying pads; and filters. Present nu.. .~ fabrics that have a low level of crimps and thus lo a low bulk are, for example, highly suitable for protective 'J~ ~~ r, drapes, wraps and cloth-like outer cover materials for absoLI,~ and personal care articles.
The fQllowing eYamples are provided for illustration ~uL~06es and the invention is not limited thereto.
r ~campl~ 1 (Exl) A 1.5 ounce per square yard t51 g/m ) r.~
bi~ ^ t fiber web was pLvluced in a~u,d~ e with aforementioned U.S. Patent 5,382,400. A linear low density polyethylene tLLDPE), Aspun 6811A, which is available from Dow t'h~ l, was blended with 2 wt% of a 2s Tio2 ~-...c6-.~L~te which had 50 wt~ of Tio2 and 50 wt96 of a polypropylene, and the miYture was fed to a first single screw extruder. The Tio2 used was commercially available conventional Tio2 which has an average particle size of about 0.5 ~Lm. A polypropylene, PD3445, which is 30 available from Exxon, was blended with 2 wt% of the above-described Tio2 ~v~c~ te and with 1 wt96 of a blue pigment. The blue pigment used was SCC 3185, which is available from Standridge Color Corporation, GA. The main ~ contained in SC 3185 are about 1. 4 wt96 vf 3s phthalocyanine blue and about 0. 296 of magenta ~ 18~776 .
quinacridone. The mixture was fed to a second single screw extruder. In this c .rnt polymer combination, polyproyplene is the fast solidifying polymer and LLDPE
is the slow solidifying polymer. The ~LLuded polymers S were spun into round bi~ 1. fibers having a side-by-side conf iguration and a 1:1 weight ratio of the two ~ polymers using a hj- L spinning die, which had a 0 . 6 mm spinhole diameter and a 6 :1 L/D ratio .
The melt t~, ,-LuL~g of the polymers fed into the lo splnnin~ die were kept at 450F (232C), and the spinhole tllL~ uyll~uL rate was o s gram/hole/minute. The bi~ L fibers exiting the spinning die were ~ .- l ed by a flow of air applied at 45 ft3/min/inch (0.5 m3/min/cm) and at a t~ c.tuLæ of 18C. The 5u~n~hing 15 air was applied about 13 cm below the spinneret, and the quenched fibers were drawn in a fiber drawing unit of the type which is described in U.S. Patent 3,802,817 to Matsuki et al . The aspirator was ~T~ i rped with a temperature controlled fiber drawing air source, and the 20 feed air t~ CILUL~ was kept at about 350F (177C).
The ~ d fibers were drawn with the heated feed air to attain a fiber size of about 2.7 denier (3 dtex).
Then, the drawn fibers were deposited onto a foraminous forming surface with the assist of a vacuum flow to form 25 an l~nhrn~rd fiber web. The .~ d fiber webs were bonded by passing the web through a through-air bonder which is equipped with a heated air source. The heated air velocity and the t~ _L~ILUL~ of the heated air was 200 feet/minute (61 m/min) and 272F (133F), 30 respectively. The residence time of the web in the hood was about 1 second.
Based on the fact that the bulk of a ~ .væ.. fabric, in general, ~JLL ~ ingly increases with the increasing level of crimps in the fibers that forms the n-,--.~,vl:n 35 fabric, the bulk of the resulting web was measured and ~183776 compared to study the crimp ;n~ll-~in~ effect of utilizing a pigment. The bulk of the resulting web was measured using a ,Starret-type bulk tester under 0.5 psi (3.4 pKa).
The result i5 shown in Table 1.
s Co~par~tiv- l~campl~ 1 (Cl) Example 1 was repeated except 1 wt% of SCC 3185 was also added ln the LLDPE ~ nt. The result is shown in Table 1 ~ample 2 (Ex2) Example 1 was repeated except 1 wt96 of SCC 3185 was added to the LLDPE ~ , L and not to the polypropylene _, -nt. The conjugate fibers of the ~Lùduced r Jvcn 15 web had a lower level of crimps than the f ibers of Comparative Example 1, and the nul-..Jvcll web had highly u~ uniform Cv~ c and uniformity , ~Gad to the nul...uvcll web of C ~l.ive Example 1. This formation u~ is believe to result from the reduction in 20 the ~.asGI~ce of u~ Limped fibers in the web. The bulk result is shown in Table 1.
Exam~le Bulk ( inch) (mm) Exl 0 . 0825 2 .10 Cl 0 . 0790 2 . 00 Ex2 0 . 077S 1. 97 The abovQ results, which shows that the bulk of the web' of Example 1 is thicker than that of the web of Comparative Example 1, clearly ~ te that adding a pigment in the fast solidifying ~ _ t polymer composition increases the degree of- latent crimpability and thus improves the crimp level of the conjugate fiber.
n addition, Example 2 and Comparative Example _Ltlte that adding a pigment in the 510w solidifying L polymer composition decreases the degree of latent cri hil ity and thus decreases the crimp level of s the conjugate fiber, while improving the fiber coverage and uniformity of the web.
'lhe conjugate fibers can be ~Lvduced to have a controlled level of crimps while pigmenting the fibers and, thus, can be used to produce nv~ v~ fabrics having o different levels of bulk and porosity, textural properties and colors.
Although pref erred : ' ~o~ of the invention have been described herein, it will be understood by those skilled~ in the art that variation~, modifications, and e~uivalents may be made thereto without departing from the spirit of the invention or the scope of the appended c~ :lml~.
Claims (21)
1. A helically crimped, pigmented multicomponent conjugate fiber comprising at least a first composition and a second composition, said first composition comprising a first thermoplastic polymer and said second composition comprising a second thermoplastic polymer which has a different solidification period than said first thermoplastic polymer, wherein one of said first and second compositions contains an effective amount of a pigment.
2. The crimped, pigmented conjugate fiber of claim 1 wherein said pigment is selected from organic and inorganic pigments having an average particle size equal to or less than about 0.5 µm.
3. The crimped, pigmented conjugate fiber of claim 2 wherein said pigment is an orgainic pigment selected from monoazo pigments, benizimideazalone pigments, disazo pigments, disazo condensation pigments, guinacridone pigments, diozanzine violet, vat pigments, perelene pigments, thioindigo pigments, phthalocyanine pigments, tetrachloro-isoindolinone pigments, and mixtures thereof.
4. The crimped, pigmented conjugate fiber of claim 2 wherein the component composition containing said pigment contains between about 0.005% and 0.2% of said pigment, based on the total weight of the composition.
5. The crimped, pigmented conjugate fiber of claim 2 wherein said first and second thermoplastic polymers are selected from polyolefins, polyesters, polyamides, vinyl acetate-based polymers, and blends and copolymers thereof .
6. The crimped, pigmented conjugate fiber of claim 5 wherein said first and second thermoplastic polymers have different melting points and are selected from polyolefins, polyamides, polyesters and blends and copolymers thereof.
7. The crimped, pigmented conjugate fiber of claim 6 wherein said thermoplastic polymer is polypropylene and said second thermoplastic polymer is polyethylene.
8. A nonwoven fabric comprising the crimped, pigmented conjugate fiber of claim 6.
9. A helically crimped, pigmented multicomponent conjugate fiber comprising at least a first composition and a second composition, said first composition comprising a first thermoplastic polymer and said second composition comprising a second thermoplastic polymer which has a different solidification period than said first thermoplastic polymer, wherein one of said first and second compositions contains a higher amount of a pigment.
10. The crimped, pigmented conjugate fiber of claim 9 wherein said pigment is selected from orgainic and inorganic pigments having an average particle size equal to or less than about 0.5 µm.
11. The crimped, pigmented conjugate fiber of claim 10 wherein said pigment is an organic pigment selected from monoazo pigments, benzimideazalone pigments, disazo pigments, disazo condensation pigments, quinacridone pigments, dioxanzine violet, vat pigments, perelene pigments, thioindigo pigments, phthalocyanine pigments, tetrachloro-isoindolinone pigments, and mixtures thereof.
12. The crimped, pigmented conjugate fiber of claim 10 wherein the component composition containing the higher amount of said pigment contains at least about 25% more of said pigment than the other component composition.
13. The crimped, pigmented conjugate fiber of claim 10 wherein said first and second thermoplastic polymers are selected from polyolefins, polyesters, polyamides, vinyl acetate-based polymers, and blends and copolymers thereof.
14 . The crimped, pigmented conjugate fiber of claim 13 wherein said first and second thermoplastic polymers have different melting points and are selected from polyolefins, polyamides, polyesters and blends and copolymers thereof.
15. The crimped, pigmented conjugate fiber of claim 14 wherein said thermoplastic polymer is polypropylene and said second thermoplastic polymer is polyethylene.
16. A nonwoven fabric comprising the crimped, pigmented conjugate fiber of claim 13.
17. A process for simultaneously pigmenting and controlling the level of latent crimpability of a crimpable multicomponent conjugate fiber, said conjugate fiber comprising at least a first composition and a second composition, said first composition comprising a first thermoplastic polymer, said second composition comprising a second thermoplastic polymer, and said first thermoplastic polymer having a faster solidification
18 period than said second thermoplastic polymer, wherein the process comprises:
a) adding disparate amounts of a pigment in said first and second compositions, b) spinning a conjugate fiber, said conjugate fiber having a crimpable configuration that arranges said compositions in substantially distinct sections across the cross-section and extends said compositions continuously along the length of said conjugate fiber, wherein said process increases the level of latent crimpability when a higher amount of said pigment is added in said first composition and decreases the level of latent crimpability when a higher amount of said pigment is added in said second composition.
18. The process of claim 17 wherein said pigment is selected from organic and inorganic pigments having an average particle size equal to or less than about 0.5 µm.
a) adding disparate amounts of a pigment in said first and second compositions, b) spinning a conjugate fiber, said conjugate fiber having a crimpable configuration that arranges said compositions in substantially distinct sections across the cross-section and extends said compositions continuously along the length of said conjugate fiber, wherein said process increases the level of latent crimpability when a higher amount of said pigment is added in said first composition and decreases the level of latent crimpability when a higher amount of said pigment is added in said second composition.
18. The process of claim 17 wherein said pigment is selected from organic and inorganic pigments having an average particle size equal to or less than about 0.5 µm.
19. The process of claim 18 wherein said first and second thermoplastic polymers are selected from polyolefins, polyesters, polyamides, vinyl acetate-based polymers, and blends and copolymers thereof.
20. The process of claim 18 wherein said crimpable conjugate fiber is crimped by a heat treatment.
21. A nonwoven fabric produed in accordance with the process of claim 20.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US52170895A | 1995-08-31 | 1995-08-31 | |
| US08/521,708 | 1995-08-31 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2183776A1 true CA2183776A1 (en) | 1997-03-01 |
Family
ID=24077812
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2183776 Abandoned CA2183776A1 (en) | 1995-08-31 | 1996-08-20 | Crimped pigmented conjugate fibers |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2183776A1 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10271999B2 (en) | 2014-11-06 | 2019-04-30 | The Procter & Gamble Company | Crimped fiber spunbond nonwoven webs/laminate |
| US10357410B2 (en) | 2014-11-06 | 2019-07-23 | The Procter & Gamble Company | Pre-strained laminates and methods for making the same |
| US11213436B2 (en) | 2017-02-16 | 2022-01-04 | The Procter & Gamble Company | Substrates having repeating patterns of apertures for absorbent articles |
-
1996
- 1996-08-20 CA CA 2183776 patent/CA2183776A1/en not_active Abandoned
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|---|---|---|---|---|
| US10271999B2 (en) | 2014-11-06 | 2019-04-30 | The Procter & Gamble Company | Crimped fiber spunbond nonwoven webs/laminate |
| US10357410B2 (en) | 2014-11-06 | 2019-07-23 | The Procter & Gamble Company | Pre-strained laminates and methods for making the same |
| US10646381B2 (en) | 2014-11-06 | 2020-05-12 | The Procter & Gamble Company | Crimped fiber spunbond nonwoven webs / laminates |
| US11135103B2 (en) | 2014-11-06 | 2021-10-05 | The Procter & Gamble Company | Apertured webs and methods for making the same |
| US11202725B2 (en) | 2014-11-06 | 2021-12-21 | The Procter & Gamble Company | Crimped fiber spunbond nonwoven webs / laminates |
| US11324645B2 (en) | 2014-11-06 | 2022-05-10 | The Procter & Gamble Company | Garment-facing laminates and methods for making the same |
| US11491057B2 (en) | 2014-11-06 | 2022-11-08 | The Procter & Gamble Company | Crimped fiber spunbond nonwoven webs / laminates |
| US11633311B2 (en) | 2014-11-06 | 2023-04-25 | The Procter & Gamble Company | Patterned apertured webs |
| US11766367B2 (en) | 2014-11-06 | 2023-09-26 | The Procter & Gamble Company | Patterned apertured webs |
| US11813150B2 (en) | 2014-11-06 | 2023-11-14 | The Procter & Gamble Company | Patterned apertured webs |
| US11998431B2 (en) | 2014-11-06 | 2024-06-04 | The Procter & Gamble Company | Patterned apertured webs |
| US11213436B2 (en) | 2017-02-16 | 2022-01-04 | The Procter & Gamble Company | Substrates having repeating patterns of apertures for absorbent articles |
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