CA2064632A1 - Spinneret for hollow trilobal cross-section filament - Google Patents

Abstract

HOLLOW TRILOBAL CROSS-SECTION FILAMENT

Abstract of the Invention A spinneret plate for the manufacture of trilobal fiber with an approximately axially central extending void, said spinneret having at least one filament forming bore group having a center and said bore group having three openings, each of said openings being approximately Y-shaped with one long leg defining an axis and the axis of each long leg converging on the center of the bore group and said opening having two shorter legs, each of the shorter legs of the same Y being divergent toward said center.

Description

3436 ( 10297-A ) 2064$32 SPINNERET FOR HOLLOW TRILOBAL CROSS-SECIION FII~MENT

5Field of the Invention l~is invention relates generally to synthetie polymeric fibrous materials. More specifically, this invention relates to spinnerets for producing hollow trilobal cross-section filarnents.
Background of the In~ention 10For many uses of ffbrous synthetic polymers, it is desirable to m~mn~e the weight of fiber needed to spread over an area This qualitative property of a ~ber is known as "cover". Another quality of fibers for certain end uses (like for carpet yarn) is the ffber's ability to hide soil. Yet, while for some end uses it is irnportant to obtain high cover and good soil hidingt sparkle and/or luster should not be sacriffced. For exarnple, carpet yarns 15should provide the greatest cover and hide soil well, yet remain lustrous. Efforts to achieve a fabric having these characteristics have largely failed since fiber properties leadJng to soil hiding tend to lessen luster. Presently, Applicants are unaware of any ffber which effectively achieves all these qualities.
Trilobal fibers are known to provide cover superior to round cross-sections and 20it is known to make trilobal and pseud~trilobal ~laments (e.g., deltas, 'r-shapes).
emplary are U.S. Patent No. 3,981,948 to Phillips, U.S. Patent No. 3,194,002 to Raynolds et al, U.S. Patent No. 2,939,201 to Holland, U.S. Patent No. 4,492,731 to Banlcar et al. and Japanese Kokai 42-22574.

2064~32 It is also known to provide voids in filaments and that many times these voids result in improved soiling hiding performance. U.S. Patent No. 3,745,061 to Champaneria et al. and U.S. Patent No. 4,407,889 to Gintis et al. show non-round filaments having one or more voids.
S It is known also to provide trilobal or pseudo-trilobal fibers which have one or more voids. Exemplary are U.S. Patent No. 3,095,258 to Scott, U.S. Patent No. 3,357,048 to Cobb, Jr., U.S. Patent No. 3,493,459 to McIntosh et al., U.S. Patent No. ~,558,420 to Opfell, U.S. Patent No. 4,279,053 to Payne et al., U.S. Patent No. 4,364,996 to Sugiyama, U.S. Patent No. 4,956,237 to Samuelson and British Patent No. 843,179 to Siemer et al.
U.S. Patent No. 4,648,830 to Peterson et al. discloses a spinneret for manufacturing hollow trilobal cross-section filaments. The filaments disclosed therein have one axially extending hole in each lobe.
~mmaTy of the Invention The present invention provides a spinneret plate for the manufacture of trilobalfiber hav~ng an approx~nately central void. The spinneret bas at least one filament form~ng bore group having a center and three openings. Each of the openings are Y-shaped vith one long leg defining an axis and the axis of each long leg converglng on the center of the bore group. The opening also has two shorter legs, each of the shorter legs of the same Y diverge toward the center of the bore group.
ZO It is an object of the present invention to provide an improved hollow spinneret for producing trilobal ~lament.

r 2~6~632 Related objects and advantages will be apparent to the ordinarily skilled artisan after reading the following detailed description of the invention.
Brief Description of the Drawin,es FIG. 1 is a plan view of a spinneret according to the present inventiorL
S FIG. 2 is a plan view of another spinneret according to the present inventiorL
FIG. 3 is a cross-sectional plan view of a filarnent produced by a spinneret of the present invention.
Detailed Description Qf the Preferred Embodiments The term "modlfication ratio" (MR) means the ratio of the radius R2 of the circumscribed circle to the radius Rl of the inscribed circle as shown in FIG. 3. The term ~arm angle" (AA) is the angle formed by extension of sides of an arm as shown in FIG.

2, FIG. 1 is a plan view of one filament forming bore group of a splnneret of the present inventionL Bore group 10 consists of three approximately "Y" shaped holes, 11, 11' and 11~. Each Y~shaped hole has long legs, 12, 12' and 12", and short legs, 13, 13' and 13". The angle between legs 12 and 12' is typically about 80 to about 160', preferably about 100- to about 140 and need not be uniforrrL R~ is preferably from about 0.5 to about 6 mrn, more preferably about 1.5 to about 3.0 mtrL R~ is preferably from about 03 to about 2.5 mm but more preferably from about O.S to about 1.5 mrrL
The width of eacb leg is typically between about 0.05 to about 0.15 mm, preferably about 0.06 to about 0.10 mm. The gap between legs 13 and 13' is about 0.05 to about 0.25 rnm, preferably about 0.08 to about 0.20 rnm. Legs 13 and 12 are of sufficient length to meet the limitations of Rl and R2.
Although any filament count yarn can be manufactured, to illustrate the present invention a spinneret is cut with 58 ~llarnent bore groups arranged in a circular layout S with 8 rows and 6 to 9 capillaries per row of filament forn~ing capillaries. Nylon 6 polyrner is extruded at normal conventional spinning conditions into a quench stack, drawn, and taken up onto the package where it is further processed into typical carpet yarn. This carpet yarn is then tufted into a carpet using conventional tufting methods and the face yarn of the carpet is observed to have improved apparent bulk, luster, soil 10 hiding, resiliency and appearance retention compared to previously known trilobal carpet yarns having no central void.
FIG. 2 is an alternate forrn of the spinneret of the present invention.
~ e spinneret of the present invention wili create a filament of ~ber having a cross section very similar to that depicted in FIG. 3. ~IG. 3 is an enlarged view of fiber 15 20 which is representative of the present invention. Filament 20 is trilobal having three (3) lobes, 21, 22 and 23 and axially extending, more or less central, void 25.
According to the present invention, filament 20 preferably has a modiffcation ratio of bet~veen about 2.5 to about 6, an arm angle between about 7- and 35-. The approximately central void represents about 3 to 10 percent, preferably 5 to 8 percent, 20 of the total fiber volume measured including the volume of the void. This ffber 20 is the subject of copending U.S. Patent Application Serial No.

2~64632 Using the spinneret of the present invention filaments may be prepared from syntbetic thermoplastic polymers which are melt spinnable. Exemplary polyrners are polyamides such as poly(hexarnethylene adipamide), polycaprolactam and polyarnides of bis(4-arninocyclohexyl)methane and linear aliphatic dicarboxylic acids containing 9,10 and 12 carbon atorns; copolyamides; polyester such as poly (ethylene) terephthalic acid and copolymers thereof; and polyolefins such as polyethylene and polypropylene. Bothhéterogeneous and homogeneous rnLxtures of such polymers may also be used.
As is apparent to one ordinarily sldlled in tbe art, the ~arnents can be prepared hy knovn methods of spinning filaments. Molten polyrner is spun through spinneret orifices shaped to provide the desired void volume and filament cross-sections under spinning conditions which give the desired denier. Specific spinning conditions and spinneret orifices, shapes and dimensions will vary depending upon the particular polymer and filament product being spurL
To achieve thc desired pcrcent void, the spinning and quenching conditions arc modificd appropriately. For cxarnple, thc percent void can generally be increased by morc rapid querlching of the molten filarnents by increasing thc polymer melt viscosiq.
Test Mcthods Pcrcent Void:
The filarnent ends of a length of yarn weighing from 6 to 8 grams are sealed by mclting with a flame. Thc yarn is weighed. Using a conventional pycnometer lthe yarn density is determined. The density of a control solid filament yarn is 2~64~32 also deterrnined with the same method as a control. Percent void is then calculated by subtracting the density of the hollow filament yarn from the density of the solid control, dividing the result by the density of the solid Slarnent yarn and then multiply~ng by 100.
5 Soilin~:
3 ft x 6 ft mock-dyed carpet samples, made from fibers with various cross-sections (of interest), are installed in a heavily traveled corridor for 50,000 passes.
The sarnples are then cleaned with a standard vacuum cleaner and ranked for degree of soiling. Lower numbers represent less degree of soiling.
10 Arm ~n~le:
Fiber cross sections are magmfied (300X) to determine the arm angle. Two tangent straight lines are drawn for each arm and the angle formed from the two straight lines is measured. The reported arm angle represents the average of ten measurements.
lS I~:
For carpet:
Cut pile carpets are made by standard tufting methods from cabled and heatset yarns. After mock dyeing, the carpets are visually ranked for luster. Lower numbers represent higher degree of luster.

2~64~32 For yarn:
A recording gon~ophotometer (HunterLab Gon~opbotometer GP~ Senal 1050) is used to obtain reaectance readings. As illustrated in the following diagram, goluophotometers are used to take reflectance readings at varymg angles. A fixedS angle of incidence (60 degrees) and vaned angle of detection (-120 to 30 degrees~
is used. Yarn samples are wound in parallel on a 15" x 4" card. There are about four to five layers of yarn on each card. The measurement conditions are:

neutral density filter #25 incident ang1e - 60 degrees scanned from -120 to -30 degrees Schematic diagram of the measurement components in a goniophotometer:
~tD~$ C~DT~, IV~T
IJOHT~OUltC V~l~JLI
~7~J

U~
The actual specular peak for each sample is obtained from the recording chart.
The angle is about 60 degrees. Luster is calculated by the following equation:
L = (1-D/S) X 100 Where D is percent reflectance reading of diffused light and S is percent re~ectance reading of specular peal Cover:
Two types of samples, one heatset and one not, are bulked in hot water (210-F) for thirty rn~nutes, dried and conditioned (68~ F, 65% RH) overnight. A
length of each yarn weighing about four grams is collected and its exact weight S deterrnined. Individual specimens are ~uffed by hand and placed in a Teaon cylinder ( 4 X 20 cm) loosely. An Instron instrument is used to measure the space a sample occupies at 9/10full scale load (9,000 g). Specific volume of thesample is calculated and expressed in cc/g. This procedure is repeated three times for each sample. The average of the three measurements is reported.
Car~et Wear:
Swivel chair test:
A carpet sample is cut to 53 inches x 48 inches. Tbe carpet sample is taped to a platforrn witb carpet tape. A metal chair with casters is filled with 100 Ibs weigbt and put onto the carpet. The cbair is hooked to a motorized plunger rod and rotates on the carpet while the plunger rod cycles back and forth. The orientation of the carpet sample is periodically changed. At tbe end of 1,500 cycles, the degree of wear is assessed by a paired comparison.
Paired comparison:
A paired comparison test is conducted using eleven observers. The objective of the examination is to compare two carpets at a time and to select a carpet sample that bas better overall appearance after a fixed amount of wear. The data 2064~32 received from the observers is processed by using a preference table. The observer's entry is treated in the follow~ng way:
S represents the score A, represents carpet sample i in a series S Aj represents carpet sample j in a series t represents the total number of samples in the paired comparison evaluation If Al > Al then S~J =
If A~ = A~ then Sy = 03 If Al < A~ then S,J = 0 If Sy = 1 then SJl = 0 If Sy = 05 then Sj~ = O.S
If S,J = O then SJI = 1 T~erefore SJ~ S4 S4 3 t (t~1)/2 206~6~2 The preference table for paired comparison evaluation of ~ive samples:

Table 1 (j) A- A2 A3 A, AS Total Score S Al ' S12 S~3 S1~ S~S ~ S~J
A~ S2~ - S23 S~ S2s ~ S~
(i) A3 S31 S32 - S3~ S35 . 2 S3 A~ S~l S.~2 S~3 ~ S~5 ~ SJ~
A5 S51 SS2 S53 S5~ - ~ S3 Exam~le A spinneret having 58 ~lament capillaries is arranged in a circular layout with eigbt rows and 6 to 9 capillaries per row. The capillaries are formed according to PIC~.
2 and are offset with respect to tbe capillaries of each next adjacent row. Nylon 6 lS polymer is extruded with normal conventional spinning conditions into a quench stack, drawn, textured and taken up onto a package where it is further processed into typical carpet yarn. Tbe carpet yarn is then tufted into a primaly backing using conventional tufting methods to make sarnples 6, 7 8 and d in tbe following tables. Samples A and C are untufted carpet yarn. The face yarn of the carpet samples exhibits excellent bulk 20 luster, soiling hiding, resiliency and appearance retention.

206~32 Comparative E~xam~le U.S. Patent No. 4,492,731 to Banlcar et al. is followed ~o make samples 2, 3, 4, 5, C, b and c below. Samples 1 and a are other solid trilobal cross-sections.

Table 2 ID l'wist klB ~m Penier ~ YQi~ ~ Soilin~
(turn/in) ~a~ (cc/g~ (%) 1 0 2.6 21 16 4.2 0 2 3 2 0 3.3 19 16 4.6 0 4 4 3 0 3.6 14 16 4.9 0 4 4 4 0 2.8 28 16 4.6 0 2 3 0 35 20 16 4.8 0 4 4 6 0 2.5 35 20 5.2 6 7 0 3.1 11 20 6.2 5 3 2 8 0 5.7 7 20 6.7 5 4 3 206~632 ~k~
I12Twist ~
(hlrn/in) (cc/g)Photometer A 1.6 2.6 4.9 67 3.6 4.0 C 1.6 2.6 4A 66 3.6 3.7 The statistical analysis of total scores from the paired comparison test (11 observers) on the swivel chair worn (1,500 ~cles) tufted carpet tiles (two-ply heatset, 3.75 tpi, 1/10 gauge tufter, 0.18 inch pile height, 26 oz. per square yard) is listed in the following Table 4:
1S Table 4 2ellier 5~ ~
(turn/~) ~ (cc/g) (~o) a 3.8 25 21 19 43 0 2 2.45 b 3.8 3.0 14 19 5.0 0 3 259 c 3.8 3.1 21 19 5.2 0 2 1.64 d 3.8 2.8 24 19 5.7 6 1 7,09

Claims

What is claimed is:

1. A spinneret plate for the manufacture of trilobal fiber with an approximately central axially extending void, said spinneret having at least one filament forming bore group having a center and said bore group having three openings, each of said openings being approximately Y-shaped with one long leg defining an axis and the axis of each long leg converging on the center of the bore group and said opening having two shorter legs, each of the shorter legs of the same Y being divergent toward said center.