P/00/011 Regulation 3.2 AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION FOR A DIVISIONAL PATENT ORIGINAL Name of Applicant: E. I. du Pont de Nemours and Company Actual Inventors: SAMUELSON, H. Vaughn SAMANT, K. Ranjan CHANG, Jing Chung Address for Service: Houlihan 2 Level 1, 70 Doncaster Road Balwyn North Victoria 3104 Australia Invention Title: POLY-TRIMETHYLENE TEREPHTHALATE SOLID CORE FIBRILLATION-RESISTANT FILAMENT HAVING A SUBSTANTIALLY TRIANGULAR CROSS SECTION, A SPINNERET FOR PRODUCING THE FILAMENT, AND A CARPET MADE THEREFROM The following statement is a full description of this invention, including the best method of performing it known to the Applicant: 1 TITLE POLY-TRIMETHYLENE TEREPHTHALATE SOLID CORE FIBRILLATION RESISTANT FILAMENT HAVING A SUBSTANTIALLY TRIANGULAR CROSS 5 SECTION, A SPINNERET FOR PRODUCING THE FILAMENT, AND A CARPET MADE THEREFROM The present application is a divisional application from Australian patent application number 2009327479. The 10 entire disclosures of Australian patent application number 2009327479 and its corresponding International application, PCT/US2009/067982, are incorporated herein by reference. This application is a continuation-in-part of U.S. 15 Patent Application Serial No. 12/338,412, filed December 18, 2008, and assigned to the assignee of the present invention. BACKGROUND OF THE INVENTION Field of the Invention This invention relates to a 20 poly-trimethylene terephthalate solid core fibrillation resistant synthetic filament, to a spinneret for producing the filament, and to a carpet made therefrom. Description of the Art Background The ability of a 25 tufted carpet made from synthetic polymeric filaments to retain its textured appearance, or "newness", tends to degrade over time. One cause of this appearance degradation is known as "fibrillation" that is produced by fraying of the carpet's filaments by use. 30 Various industry standard test methods, e.g., tetrapod walker test (ASTM D5251), hexapod walker test (ASTM D5252), Vetterman drum test (ASTM D5417), chair castor test and Phillips roll chair test are available to measure texture retention. Carpets samples are graded against a subjective 35 scale after they have been subjected to these tests for predetermined number of cycles. For example, tests performed on carpets made using petroleum-based poly-trimethylene terephthalate fibers 2 having trilobal cross-section with a modification ratio of 2.0 and a 26.5 degree arm angle show significant fibrillation damage after 20,000 cycles in the Phillips roll chair test. Damaged trilobal filaments extracted from 5 worn carpets after such test show severe deformities. One typical mode of deformation is manifested by adjacent lobes of the originally trilobal filament being bent toward each other, resulting in a filament having an elongated, compacted cross section. 10 In view of the foregoing it is desirable to produce filaments with cross-sections that are inherently more resistant to fibrillation, and are thereby able to provide superior texture retention during accelerated wear tests described above and exceptional durability in use. 15 SUMMARY OF THE INVENTION In a first aspect the present invention is directed toward a solid core, fibrillation-resistant, synthetic polymeric filament having three substantially equal length 20 convex sides. Each side meets an adjacent side through a substantially rounded tip centered on a respective circle of curvature spaced from the axis of the filament by a distance "a". Each rounded tip has a radius substantially equal to a length "b". 25 Each tip lies on a circumscribed circle having a radius substantially equal to a length (a + b) and the midpoint of each side lies on an inscribed circle having a radius substantially equal to a length "c". The filament having a modification ratio (MR) defined by the ratio of 30 the radius (a + b) of the circumscribed circle to the radius (c) of the inscribed circle, wherein: the filament has a denier-per-filament ("dpf") in the range 10 < "dpf" < 35; the distance "a" lies in the range 0.00025 inches 35 (6 micrometers) < 'a" < .004 inches (102 micrometers); 3 the distance "b" lies in the range from 0.00008 inches (2 micrometers) < "b" < .001 inches (24 micrometers); the distance "c" lies in the range from 0.0003 5 inches (8 micrometers) < "c" < .0025 inches (64 micrometers); and the modification ratio ("MR") lies in the range from about 1.1 < "MR" < about 2.0. More particularly, 10 the filament has a denier-per-filament ("dpf") in the range 12 < "dpf" < 32; the distance "a" lies in the range 0.00035 inches (9 micrometers) < "a" < .003 inches (76 micrometers); 15 the distance "b" lies in the range from 0.00010 inches (3 micrometers) < "b" < .00095 inches (25 micrometers); the distance "c" lies in the range from 0.0005 inches (10 micrometers)< "c" < .002 inches (51 20 micrometers); and the modification ratio ("MR") lies in the range from about 1.1 < "MR" < about 2.0. Preferably, the synthetic polymer is substantially poly-trimethylene terephthalate, and more preferably, the 25 poly-trimethylene terephthalate has a 1,3 propane diol that is biologically produced. Alternately, poly-trimethylene terephthalate may come from renewably resourced routes. The synthetic polymer may be pigmented and/or may have a delusterant therein. 30 The filament has a tenacity greater than 1.5 grams per denier. -0-0-0 In another aspect the present invention is directed to a carpet made from filaments as described above. 35 -0-0-0 In still another aspect the present invention is directed to a spinneret plate having a plurality of 4 orifices formed therein for forming the solid core fibrillation-resistant, synthetic polymeric filament. Each orifice has a center and three sides with each side terminating in a first and a second end point and with a 5 midpoint therebetween. In a first embodiment of a spinneret in accordance with this aspect of the invention the first end point of one side is connected to the second end point of an adjacent side by a circular end contour having a radius 10 equal to a dimension "C". The center point of each end contour is disposed a predetermined distance "D" from the center of the orifice. In accordance with this embodiment: the distance "C" lies in the range 0.0015 inches 15 (38 micrometers) < "C" < .0040 inches (102 micrometers); the distance "D" lies in the range from 0.0150 inches (381 micrometers) < "D" < .0300 inches (762 micrometers); 20 and more particularly: the distance "C" lies in the range 0.0020 inches (51 micrometers) < "C" < .0035 inches (89 micrometers); the distance "D" lies in the range from 0.0175 25 inches (445 micrometers) < "D" < .0280 inches (711 micrometers). In an alternate embodiment of a spinneret in accordance with this aspect of the invention the end 30 contour connecting the first end point of one side to the second end point of an adjacent side is defined by at least two linear edges that intersect in an apex. The first end point of each side is spaced from the second end point of an adjacent side by a baseline that 35 itself intersects with a reference radius emanating from the center point. The intersection point between the baseline and the reference radius lies a distance "G" along the reference radius from the center of the orifice. The 5 baseline has a predetermined length "2F". The apex is spaced a dimension "E" from an intersection of the baseline and the reference radius. In accordance with this embodiment: 5 the distance "E" lies in the range 0.0025 inches (64 micrometers) < "E" < .0150 inches (381 micrometers); the distance "F" lies in the range from 0.0015 inches (38 micrometers) < "F" < .0040 inches 10 (102 micrometers); and the distance "G" lies in the range from 0.0150 inches (381 micrometers) < "G" < .0300 inches (762 micrometers); and more particularly: 15 the distance "E" lies in the range 0.0030 inches (76 micrometers) < "E" < .0100 inches (254 micrometers); the distance "F" lies in the range from 0.0020 inches (51 micrometers) < "F" < .0035 inches 20 (89 micrometers); and the distance "G" lies in the range from 0.0175 inches (445 micrometers) < "G" < .0280 inches (711 micrometers). 25 Regardless of the form taken by the end contour, each side of the orifice may be either substantially concave or substantially linear. If orifice has substantially concave sides, each side lies on a reference circle having a radius of dimension 30 "B". The center of the reference circle is located on a reference radius emanating from the center point of the orifice and passing through a midpoint of a side. The center of the reference circle is disposed a predetermined distance "A" along the reference radius from the central 35 axis of the orifice. The outermost point on each circular end contour lies on a circumscribed circle having a radius "(C+D)" (as defined above) centered on the center of the orifice. The 6 midpoints of each side lying on a inscribed circle having a radius "H". [In the case of an orifice with concave sides the radius "H" is equal to the value (A-B)]. The orifice has a modification ratio ("MR") defined by 5 the ratio of the radius (C+D) of the circumscribed circle to the radius "(A-B)" of the inscribed circle, thus, "MR" = (C+D) / "(A-B)", wherein the distance "A" lies in the range 0.0300 inches (762 micrometers) < "A" < .0900 inches (2286 10 micrometers); the distance "B" lies in the range from 0.0200 inches (508 micrometers) < "B" < .0800 inches (2032 micrometers); the ratio (A/B) lies within the range from about 15 1.0 < (A/B) < about 1.6; and the modification ratio ("MR") lies in the range from about 1.5 < "MR" < about 4.5. More particularly: the distance "A" lies in the range 0.0300 inches 20 (762 micrometers) < "A" < .0700 inches (2032 micrometers); the distance "B" lies in the range from 0.0200 inches (508 micrometers) < "B" < .0800 inches (1778 micrometers); 25 the ratio (A/B) lies within the range from about 1.1 < (A/B) < about 1.5; and the modification ratio ("MR") lies in the range from about 1.8 < "MR" < about 3.5. 30 If orifice has substantially linear sides with circular end contours the outermost point on each end contour again lies on a circumscribed circle having the radius "(C+D)" (as defined above) centered on the center of the orifice while the midpoints of each side lying on a 35 inscribed circle having the radius "H" centered on the center of the orifice. 7 In the case of an orifice with linear sides and circular end contours the distance "H" (i.e., the radius of the inscribed circle) lies in the range from: 0.0090 inches (229 micrometers) < "H" < 0.0190 inches 5 (483 micrometers); and more preferably, in the range from: 0.0108 inches (274 micrometers) < "H" < 0.0175 inches (445 micrometers). The modification ratio ("MR") for such an orifice with 10 substantially linear sides is also defined by the ratio of the radius (C+D) of the circumscribed circle to the radius "H" of the inscribed circle, thus, "MR" = (C+D) / "H". The modification ratio ("MR") lies in the range from 15 about 1.6 < "MR" < about 2.5; and more particularly, the modification ratio ("MR") lies in the range from about 1.7 < "MR" < about 2.3. For orifices having linear sides and linear end 20 contours the distance "H" (i.e., the radius of the inscribed circle) lies in the range from: 0.0088 inches (224 micrometers) < "H" < 0.0185 inches (470 micrometers) and more preferably, in the range from: 25 0.0105 inches (267 micrometers) < "H" < 0.0170 inches (432 micrometers). The modification ratio ("MR") for orifices having linear sides and linear end contours is also defined by the 30 ratio of the radius (E+G) of the circumscribed circle to the radius "H" of the inscribed circle, thus, "MR" = (E+G) / "H" The modification ratio ("MR") lies in the range from about 1.6 < "MR" < about 2.5, and more particularly, the 35 modification ratio ("MR") lies in the range from about 1.7 < "MR" < about 2.3. 8 BRIEF DESCRIPTION OF THE DRAWINGS The invention will be more fully understood from the following detailed description taken in connection with the accompanying Figures, which form a part of this application 5 and in which: Figure 1 is an end view of a filament in accordance with the present invention taken in a plane perpendicular to the longitudinal axis of the filament; Figure 2A is an end view a first embodiment of a 10 spinneret plate having a filament-forming orifice formed therethrough for producing a filament in accordance with the present invention, the view being taken in a plane perpendicular to the central axis of the filament-forming orifice with the orifice having rounded end contour regions 15 and concave sides; Figure 2B is an end view, similar to the view of Figure 2A, showing an alternate embodiment of a spinneret plate for producing a filament in accordance with the present invention, the filament-forming orifice having 20 rounded end contour regions and linear sides; Figure 3A is an end view an alternate embodiment of a spinneret plate generally similar to that shown in Figure 2A in that the orifice has concave sides, but with end contour regions each comprising at least two linear edges; 25 Figure 3B is an end view an alternate embodiment of a spinneret plate generally similar to that shown in Figure 2B in that the orifice has linear sides, but with end contour regions each comprising at least two linear edges; Figure 4 is stylized diagrammatic illustration of a 30 spinning arrangement that utilizes a spinneret plate as shown in Figures 2A, 2B, 2C, 3A or 3B for spinning filaments in accordance with the invention; Figure 5 is stylized diagrammatic illustration of a carpet fabricated using filaments of the invention; 35 Figure 6A is stylized diagrammatic side sectional illustration of a rotating ball mill test chamber used to test filaments of the invention; 9 Figure 6B is a diagrammatic end view illustrating the operation of the ball mill test when testing filaments of the present invention; Figures 7A and 7B are photographs illustrating a 5 comparative trilobal cross section filament before and after fibrillation testing using the rotating ball mill test chamber of Figure 6A; Figures 8A and 8B are photographs illustrating a comparative round cross section filament before and after 10 fibrillation testing using the rotating ball mill test chamber of Figure 6A; and Figures 9A and 9B are photographs illustrating a filament in accordance with the present invention before and after fibrillation testing using the rotating ball mill 15 test chamber of Figure 6A. DETAILED DESCRIPTION OF THE INVENTION Throughout the following detailed description similar reference numerals refer to similar elements in all figures 20 of the drawings. Figure 1 is a cross-section view through a solid core, fibrillation-resistant, synthetic polymeric filament 10 in accordance with one aspect of the present invention, taken 25 in a plane substantially perpendicular to the central longitudinal axis 10A of the filament. The filament 10 is preferably fabricated from a poly trimethylene terephthalate polymeric material. More preferably, the poly-trimethylene terephthalate polymeric 30 material wherein the 1,3 propane diol is biologically produced, although it should also be understood that the 1,3 propane diol derived via a petroleum route may also used in combination with biologically based 1,3 propane diol. 35 The polymeric material may be pigmented with a solution dyed color additive or a delusterant such as TiO2. Alternatively, the polymeric material may be non-pigmented for later dying. The polymeric material may contain UV 10 stabilizer(s), anti-oxidant(s) and/or other performance improving additive(s) (including flame retardant(s), such as phosphorus- and/or nitrogen-containing compound(s); toughening agent(s); and/or nucleation-inhibiting agent(s). 5 The filament may also be fabricated from other polymeric materials, such as polyester, nylon, polypropylene and blends thereof. As seen from Figure 1 the filament 10 is, in the cross section plane perpendicular to its axis, three-sided in 1 2 3 10 form. The sides 121, 12 , 12 are substantially equal in 1 2 3 length. Each side 12 , 122, 12 is generally convex in 1 2 3 shape with a mid-point 12M , 12M , 12M therealong. Each 1 2 3 side 12', 12 , 12 lies on a respective circle of curvature 1 2 3 having a radius 12R , 12R , 12R . Each circle of curvature 1 2 3 15 is centered on a respective center point 12C , 12C , 12C 1 2 3 The center points 12C , 12C , 12C each lie on a respective reference radius emanating from the axis 10A of the filament 10. 1 2 3 Each respective side 12 , 12 , 12 meets with a side 20 adjacent thereto through a substantially rounded tip 141, 2 3 14 3, respectively. The rounded contour of each tip 1 2 3 14 , 14 14 lies on a circle of curvature centered on a 1 2 3 respective center point 16 , 16 , 16 . The radius of the circle of curvature of the tips 14 1, 142, 143 is indicated 25 by the reference character "b". Each center of curvature 16 , 16 2, 163 is itself spaced by a predetermined distance "a" from the central axis 10A of the filament. Only one center of curvature (161) is shown for clarity of illustration 1 2 3 30 The outermost point of each tip 14', 14 , 14 of the filament 10 lies on a circumscribed circle 24 having a radius substantially equal to a length (a + b). The 1 2 3 1 2 midpoint 12M , 12M , 12M of each respective side 12 , 12 123 lies on an inscribed circle 26 centered on the central 35 axis 10A of the filament 10. The radius of the inscribed circle 26 is substantially equal to a length "c". Accordingly, the filament 10 exhibits a modification ratio ("MR") defined by the ratio of the radius (a+b) of the 11 circumscribed circle to the radius (c) of the inscribed circle, thus: MR = (a+b) / c. Mathematical modeling of filaments having trilobal 5 cross-section shows that lobes and the sides are susceptible to failure under compressive, bending and/or torsion loads. The effect of these stresses acting upon the filaments result in fibrillation and the corresponding texture degradation of the filament during wear. 10 Analyses also indicate that maximum bending stress is imposed on the end contour regions of the filament, while maximum torsion and compression forces are imposed substantially centrally along the sides of the filament. For example, the compressive stress ("o") at the contact 15 point between two adjacent filaments has been found to be inversely proportional to the square root of filament diameter "d" when filaments are parallel to each other, thus, o = d_'. In the case where the where the filaments are 20 perpendicular to each other, the compressive stress (" ") is inversely proportional to the 2
/
3 rd power of filament diameter, thus, o = d_'. As will be developed it is believed that the fiber 25 geometry disclosed by this invention reduces these stress levels, resulting in a filament having improved fibrillation resistant properties. Filaments in accordance with the present invention are believed to overcome weaknesses of round as well as trilobal cross-sections 30 under various loading conditions. In particular, it has been found that forming a filament with more robust end contours and more robust filament tip region will counteract bending stress imposed on the filament. If the radius of the circle of curvature 35 of the tips 141, 142, 14 is kept large stress levels at tips are lowered below the levels occurring at the lobes of a trilobal cross-section. 12 Likewise, as opposed to filaments having a round cross-section, configuring the filament with flatter, less concave sides result in filaments more able to retain their shape in the face of forces imposed by use. Filaments with 1 2 3 5 large radii 12R , 12R , 12R relative to the diameter of a round filament having an equivalent cross-sectional area lead to a substantial reduction in the compressive contact stress over round filaments. 10 Accordingly, filaments in accordance with the present invention exhibit various dimensional parameters and certain relationships therebetween, as follows: the filament has a denier-per-filament ("dpf") in the range 10 < "dpf" < 35; 15 the distance "a" lies in the range 0.0003 inches (6 micrometers) < "a" < .004 inches (102 micrometers); the distance "b" lies in the range from 0.00008 inches (2 micrometers) < "b" < .0001 inches 20 (24 micrometers); the distance "c" lies in the range from 0.0003 inches (8 micrometers) < "c" < .0025 inches (64 micrometers); and the modification ratio ("MR") lies in the range 25 from about 1.1 < "MR" < about 2.0 In a more preferred instance: the filament has a denier-per-filament ("dpf") in the range 12 < "dpf" < 32; the distance "a" lies in the range 0.00035 inches 30 (9 micrometers) < "a" < 0.003 inches (76 micrometers); the distance "b" lies in the range from 0.00010 inches (3 micrometers) < "b" < .00095 inches (25 micrometers); 35 the distance "c" lies in the range from 0.0005 inches (10 micrometers)< "c" < .002 inches (51 micrometers); and 13 the modification ratio ("MR") lies in the range from about 1.1 < "MR" < about 2.0. Preferably, the filament has a tenacity greater than 5 1.5 grams per denier. -0-0-0 In another aspect the present invention is directed to a spinneret plate 100 for forming a solid core, 10 fibrillation-resistant, synthetic polymeric filament. The plate 100 is a relatively massive member having a plurality of filament-forming orifices 102 provided therethrough. Each orifice has a center 102A. The plate 100 may be fabricated from a material such as stainless steel. 15 Suitable grades of stainless steel include 440C, 316, 17-4 PH, 430, or Carpenter 20. The steel grade selected should be free of internal defects. Typically the orifices are formed through the plate 100 using machining technology such as laser cutting or electrical discharge machining. 20 An enlarged view of a portion of the surface of a spinneret plate 100 and one of the orifices 102 formed therein is shown Figures 2A, 2B, 3A and 3B. Each of these Figures illustrates one of the various alternative configurations of an single orifice 102 in accordance with 25 various embodiments of the present invention. In general, for each embodiment of this aspect of the invention a filament-forming orifice 102 is an aperture 12 having three substantially equal length sides 1121, 112 31 2 3 112'. The midpoint 112M , 112M , 112M of each side lies on 30 an inscribed circle 113 having a radius "H" centered on the center point 102A of the orifice. Each of the sides 1121, 2 3 112 , 112 terminates in a first and a second end point, respectively indicated in the drawings by the Roman numerals I, II. 35 The first end point I of any one side is connected to the second end point II of an adjacent side by an end contour 114, 114'. The end contour 114, 114' in each of 14 the embodiments of Figures 2A, 2B and Figures 3A and 3B take alternative forms. In the embodiments illustrated in Figures 2A and 2B the end contour 114 takes the form of a circle centered on 5 center point 116 and having a radius of the dimension "C". Each center point 116 is spaced a predetermined distance "D" along a reference radius 120 emanating from the center 102A of the orifice. The outermost point on each circular end contour 114 lies on a circumscribed circle 121 centered 10 on the center 102A of the orifice and having a radius "(C+D)". The first end point I of any one side and the second end point II of an adjacent side are spaced from each other by a chord 122 of the circular end contour. Each end point I, II defines a point of tangency of the 15 circular end contour 114. The modification ratio ("MR") of an orifice is defined as the ratio of the radius of a circumscribed circle of the orifice to the radius of the inscribed circle of the orifice. 20 In a preferred implementation of this embodiment of the invention shown in Figures 2A and 2B: the distance "C" lies in the range 0.0015 inches (38 micrometers) < "C" < .0040 inches (102 micrometers); 25 the distance "D" lies in the range from 0.0150 inches (381 micrometers) < "D" < .0300 inches (762 micrometers). In a more preferred case: the distance "C" lies in the range 0.0020 inches (51 30 micrometers) < "C" < .0035 inches (89 micrometers); the distance "D" lies in the range from 0.0175 inches (445 micrometers) < "D" < .0280 inches (711 micrometers). 35 Alternatively, in the embodiments illustrated in Figures 3A and 3B, each end contours 114' is defined by at least two linear edges 126A, 126B. Any convenient number 15 of linear edge segments may be used to define an end contour 114'. In these embodiments the first end point I of any one side and the second end point II of an adjacent side are spaced from each other by a baseline 128 having a 5 length "2F". Each baseline 128 lies a predetermined distance "G" on the reference radius 120. The linear edges 126A, 126B of the contour 114' intersect each other at an apex 130 also lying on the reference radius 120. The apex 130 is spaced a distance "E" from the baseline 128. 10 The apex 130 of each end contour 114' lies on a circumscribed circle 121 centered on the center 102A of the orifice. In these Figures the circumscribed circle 121 has a radius " (G+E)". In accordance with this embodiment of the invention 15 shown in Figures 3A and 3B: the distance "E" lies in the range 0.0025 inches (64 micrometers) < "E" < .0150 inches (381 micrometers); the distance "F" lies in the range from 0.0015 inches 20 (38 micrometers) < "F" < .0040 inches (102 micrometers); and the distance "G" lies in the range from 0.0150 inches (381 micrometers) < "G" < .0300 inches (762 micrometers). 25 More preferably: the distance "E" lies in the range 0.0030 inches (76 micrometers) < "E" < .0100 inches (254 micrometers); the distance "F" lies in the range from 0.0020 inches 30 (51 micrometers) < "F" < .0035 inches (89 micrometers); and the distance "G" lies in the range from 0.0175 inches (445 micrometers) < "G" < .0280 inches (711 micrometers). 35 The orifices 102 as illustrated in Figures 2A and 3A also differ from those shown in Figures 2B and 3B in the form taken by the sides 112. 16 In the embodiments of Figures 2A and 3A the sides 123 112', 112 , 112' are generally concave in shape and lie along a circle of curvature centered on a respective center 1 2 3 of curvature 112C , 112C , 112C . Each center of curvature 5 112C 1, 112C 2, 112C is located on a reference line 134 emanating radially from the central axis 102A of the orifice. The radius of the circle of curvature has a dimension indicated by the reference character "B". Each center of curvature 112C 1, 112C 2, 112C is located a 10 predetermined distance "A" from the central axis 102A. It should be noted that the radius "H" of the inscribed circle 113 is equal to (A - B). For orifices having concave sides as shown in Figures 2A and 3A the following additional dimensional constraints 15 apply: the distance "A" lies in the range 0.0300 inches (762 micrometers) < "A" < .0900 inches (2286 micrometers); the distance "B" lies in the range from 0.0200 20 inches (508 micrometers) < "B" < .0800 inches (2032 micrometers); the ratio (A/B) lies within the range from about 1.0 < (A/B) < about 1.6; and the modification ratio ("MR") lies in the range 25 from about 1.5 < "MR" < about 4.5. More preferably: the distance "A" lies in the range 0.0300 inches (762 micrometers) < "A" < .0800 inches (2032 micrometers); 30 the distance "B" lies in the range from 0.0200 inches (508 micrometers) < "B" < .0700 inches (1778 micrometers); the ratio (A/B) lies within the range from about 1.1 < (A/B) < about 1.5; and 35 the modification ratio ("MR") lies in the range from about 1.8 < "MR" < about 3.5. 17 For orifices having concave sides (Figures 2A and 3A) the modification ratio ("MR") lies in the range from about 2.0 < "MR" < about 4.0. More preferably, the modification ratio ("MR") lies in the range from about 2.2 < "MR" < 5 about 3.5. As the radius of the circle of curvature of the side of the orifice is increased the contour of the side flattens, until at a very large radius the side becomes close to linear. 10 For orifices having linear sides and circular end contours (Figures 2B) the distance "H" (i.e., the radius of the inscribed circle) lies in the range from 0.0090 inches (229 micrometers) < "H" < 0.0190 inches (483 15 micrometers). The modification ratio ("MR") lies in the range from about 1.6 < "MR" < about 2.5. More preferably, the distance "H" lies in the range from 0.0108 inches (274 micrometers) < "H" < 0.0175 inches (445 micrometers) and the modification ratio ("MR") lies in the range from about 20 1.7 < "MR" < about 2.3. For orifices having linear sides and linear end contours (Figures 3B) the distance "H" (i.e., the radius of the inscribed circle) lies in the range from 0.0088 inches (224 micrometers) < "H" < 0.0185 inches (470 25 micrometers). The modification ratio ("MR") lies in the range from about 1.6 < "MR" < about 2.5. More preferably, the distance "H" lies in the range from 0.0105 inches (267 micrometers) < "H" < 0.0170 inches (432 micrometers) and the modification ratio ("MR") lies in the range from about 30 1.7 < "MR" < about 2.3. -0-0-0 Figure 4 is stylized diagrammatic illustration of a spinning arrangement generally indicated by the reference 35 character 200 for manufacturing bulked continuous filaments of present invention. Polymer melt is pumped through spin pack assembly 202 that includes a spinneret plate 100 having a plurality of orifices 102 shaped in accordance 18 with this invention. The spin pack assembly 202 may also contain a filtration medium. Filaments 10 of desired shapes are obtained when polymer is extruded through the spinneret plate 100 and 5 filaments are pulled through a quench chimney 204 by feed rolls 206. Finish is applied to the filaments 10 for downstream processability by a finish roll 208 located prior to the feed rolls 206. The feed rolls 206 are kept at the room temperature or maintained at a temperature 10 above polymer glass transition temperature to effectively draw and orient molecules during the draw process. Draw rolls 210, running at a predetermined speed faster than the feed rolls 206 by the amount of the draw ratio, are heated to a temperature above the glass transition temperature and 15 below the melting point of the polymer to anneal the drawn fiber. At this point the filaments may be collected by a winder 212 through a let down roll 212 or continue for further processing. In an alternate arrangement, a set of heated pre-draw rolls may be employed between the finish 20 applicator 208 and feed rolls 206. This arrangement provides additional flexibility of imparting suitable temperature and tension history to filaments to optimize draw between roll sets 206 and 210. A bulking jet 220 employing hot air or steam is used 25 to impart a random, three-dimensional curvilinear crimp to the filaments. The resulting bulked filaments are laid on to a rotating drum 224 having a perforated surface. The filaments are cooled under zero tension by pulling air through them using a vacuum pump. Water may additionally 30 be misted onto the filaments on the drum 224 to facilitate cooling. After the filaments have been cooled below the glass transition temperature, filaments are pulled off the drum 224. If desired another finish for mill processing may applied by finish roll 226. The filament bundle is 35 interlaced periodically by an interlacing jet 230 disposed between a pull roll 232 and a let down roll 234, and collected by a winder 236. -0-0-0 19 Figure 5 is stylized diagrammatic illustration of a carpet generally indicated by the reference character 300 having tufted with yarn 302 made from filaments 10 of the present invention. In the embodiment illustrated the yarn 5 302 is formed from two twisted and heat-set filaments. Alternatively, the yarn could be formed by air-entangling filaments 10 or the yarn could be directly tufted without twisting or entanglement. The yarn is tufted through a primary backing 304 to 10 form pile tufts 306. The pile tufts 306 may take the level loop form shown in Figure 5. Alternatively, the pile tufts may be multi-level loop, berber, plush, saxony, frieze or sheared form. The carpet 300 is completed by a secondary 308 adhered 15 to the primary backing 304 using an adhesive 310. Other potential end uses of the filaments of the present invention include luggage, handbags, automotive fabrics. 20 -0-0-0 Figure 6A is stylized diagrammatic illustration, taken in side section, of a rotating ball mill test chamber 400 used to test filaments 10 of the invention. Figure 6B is a 25 diagrammatic end view illustrating the operation of the ball mill test when testing filaments of the present invention. The test chamber 400 comprises a cylindrical barrel 402 closed at one end by an integral base 404. The 30 opposite end of the barrel 402 receives a lid 406. The lid 406 is secured to the rim of the barrel 402 by bolts 408. Both the base 404 and the lid 406 have an array of axially aligned mounting apertures 410 formed therein. Access to the interior of the barrel 402 is afforded 35 through a port opening 412 provided in the center of the lid 406. The port opening 412 is closed by a removable hatch 416. The hatch 416 is secured to the lid 406 by a screws 418. 20 To prepare the chamber for a test, bundles of filaments 10 under test are strung between the base 404 and the lid 406 using the mounting apertures 410. The filaments under test may be conveniently secured to the 5 surfaces of the base 404 and the lid 406, as by tape. Any convenient number of ball bearings 420 (Figure 6B) are introduced into the chamber through the port opening 412 and the hatch 416 secured. Nine millimeter (9 mm) stainless steel ball bearings may be used. 10 The dynamics of a filament test using the test chamber 400 are illustrated in Figure 6B. The test chamber 400 is placed on two driven bars 424A, 424B of a rotating mill apparatus, such as a device manufactured by U.S. Stoneware, a division of E.R. Advanced Ceramics, East Palatine, 15 Ohio. As the bars 424 are rotated in the direction 428 the bearings 420 impinge on the filaments 10 strung axially across the interior of the barrel. The test may be conducted for any convenient time period at a nominal rotational speed of one hundred rpm, although other speeds 20 in the range from about 30 to about 120 rpms may be suitable employed. Fiber cross-section images of the filaments tested using the test chamber 400 indicate fibrillation damage to the filaments that is similar to the fibrillation damage 25 done to filaments of a carpet subjected to any of the various industry standard test methods used to measure texture retention. The similarity of fibrillation damage lends confidence to conclusions regarding the fibrillation resistance of filaments tested using the chamber 400. 30 -0-0-0 EXAMPLES Example 1 (Comparative) Using a spinning arrangement as shown in Figure 4 bio-based poly-trimethylene 35 terephthalate polymer having an intrinsic viscosity of 1.02 and less than 50 ppm moisture was spun through a 17-hole spinneret suitable for trilobal cross-section filaments. The temperature set points for downstream barrels of the 21 28-mm Warner & Pfleiderer twin extruder, transfer line, pumps, pack and die were in the range of 268-270'C. The spinning throughput was 60 grams per minute. The molten filaments were cooled in the chimney, where the room air 5 was blown past the filaments using a profiled quench with air velocity in the range of 21-30 feet per minute as a function of distance from the spinneret face with higher velocity near the spinneret. Filaments were pulled by a pair of feed rolls at 60'C at a surface speed of 600 meters 10 per minute through the quench zone. Filaments were coated with a lubricant immediately prior to the feed roll. The coated filaments were drawn by a draw ratio of 3 and annealed by a pair of rolls heated to 160'C with a surface speed of 1800 meters/minute. The filaments were then 15 wound. Filaments produced had the following properties: Denier per filament = approximately 18 MR = 2.1 Arm angle = 22' 20 Tenacity of yarn, as produced, was 2.02 gm/denier. Two hundred sixty filaments were strung through the rotating ball mill test chamber 400, described earlier, under a tension of approximately 20 gm without imparting 25 any substantial twist to the yarn bundle. One hundred 9 mm stainless steel ball bearings were placed in the chamber. The test was conducted for 16 hours at 100 rpm. Cross-sectional images of yarn bundles were obtained before and after the 16 hour test using a Hardy plate and 30 an optical microscope and are shown in Figure 7A and 7B, respectively. Example 2 (Comparative) Using a spinning arrangement as shown in Figure 4 bio-based poly-trimethylene 35 terephthalate polymer having an intrinsic viscosity of 1.02 and less than 50 ppm moisture was spun through a 34-hole spinneret suitable for round cross-section filaments. The temperature set points for downstream barrels of the 28-mm 22 Warner & Pfleiderer twin extruder, transfer line, pumps, pack and die were in the range of 268-270'C. The spinning throughput was 88.1 grams per minute. The molten filaments were cooled in the chimney, where the room air was blown 5 past the filaments using a profiled quench with air velocity in the range of 21-30 feet per minute as a function of distance from the spinneret face with higher velocity near the spinneret. Filaments were pulled by a pair of feed rolls at 60'C at a surface speed of 415 meters 10 per minute through the quench zone. Filaments were coated with a lubricant immediately prior to the feed roll. The coated filaments were drawn by a draw ratio of 3.25 and annealed by a pair of rolls heated to 160'C with a surface speed of 1350 meters/minute. The filaments were then 15 wound. Denier per filament was approximately 18. Tenacity of yarn, as produced, was 2.75 gm/denier. Two hundred seventy two filaments were strung through the rotating ball mill test chamber 400, described earlier, under a tension of approximately 20 gm without 20 imparting any substantial twist to the yarn bundle. One hundred 9 mm stainless steel ball bearings were placed in the device. The test was conducted for 16 hours at 100 rpm. Cross-section images of yarn bundles were obtained before and after the 16 hour test using a Hardy plate and 25 an optical microscope and are shown in Figure 8A and 8B, respectively. Example 3 Using a spinning arrangement as shown in Figure 4 bio-based poly-trimethylene terephthalate polymer 30 having an intrinsic viscosity of 1.02 and less than 50 ppm moisture was spun through a 10-hole spinneret of present invention with following dimensions (Figure 3A): A = 0.066 inch, B = 0.0554 inch, 35 F = 0.0028 inch, G = 0.0225 inch, E = 0.0047 inch, A/B = 1.19, 23 2F/G = 0.249, E/D = 0.21, modification ratio MR = 2.6. The temperature set points for downstream barrels of 5 the 28-mm Warner & Pfleiderer twin extruder, transfer line, pumps, pack and die were in the range of 268-270'C. The spinning throughput was 30 grams per minute. The molten filaments were cooled in the chimney, where the room air was blown past the filaments using a profiled quench with 10 air velocity in the range of 21-30 feet per minute as a function of distance from the spinneret face with higher velocity near the spinneret. Filaments were pulled by a pair of feed rolls at 60'C at a surface speed of 500 meters per minute through the quench zone. Filaments were coated 15 with a lubricant immediately prior to the feed roll. The coated filaments were drawn by a draw ratio of 3 and annealed by a pair of rolls heated to 160'C with a surface speed of 1500 meters/minute. The filaments were then wound. 20 Filaments produced had the following properties: Denier per filament = approximately 18 a = 0.00083 inch b = 0.00025 inch c = 0.00077 inch 25 MR = 1.406 Tenacity of yarn, as produced, was 1.99 gm/denier. Two hundred sixty filaments were strung through the rotating ball mill test chamber 400, described earlier, 30 under a tension of approximately 20 gm without imparting any substantial twist to the yarn bundle. One hundred 9 mm stainless steel ball bearings were placed in the device. The test was conducted for 16 hours at 100 rpm. Cross section images of yarn bundles were obtained before and 35 after the 16 hour test using a Hardy plate and an optical microscope and are shown in Figure 9A and 9B, respectively. 24 Fibrillation-resistant behavior of cross-section of a filament in accordance with the present invention is easily seen from comparison of the image in Figure 9B with the images of the comparative examples shown in Figures 7B and 5 8B. Comparing Figures 7A and 7B, bending and severing of the lobes, indicating excessive fibrillation is easily seen. Similarly, there is excessive deformation of filaments having round cross-section as seen from Figures 8A and 8B. By contrast, very little deformation is seen in 10 Figure 9B when compared to as-produced filaments before the ball mill test, shown in Figure 9A. Example 4 (Comparative) Using a spinning arrangement as shown in Figure 4 bio-based poly-trimethylene 15 terephthalate polymer having an intrinsic viscosity of 1.02 and less than 50 ppm moisture was spun through a 68 hole spinneret for trilobal cross-section. The temperature set points for downstream barrels of a single screw extruder, transfer line, pumps, pack and die 20 were in the range of 230-260'C. The spinning throughput was 466.7 grams per minute. The molten filaments were cooled in the chimney, where the 16'C air was blown past the filaments. Filaments were pulled by a pair of feed rolls at 38'C at a surface speed of 1900 meters per minute 25 through the quench zone. Filaments were coated with a lubricant immediately prior to the feed roll. The coated filaments were pre-drawn by a ratio of 1.01 by a pair of rolls at 50'C with a surface speed of 1920 meters per minute. The filaments were then drawn by a ratio of 1.98 30 and annealed by another pair of heated draw rolls at 165'C running at a surface speed of 3800 meters per minute. The filaments were texturized using a stuffer-jet bulker with jet air temperature at 225 'C, interlaced and wound at 3170 meters per minute. 35 Filaments produced had the following properties: Denier per filament = approximately 19.5 Trilobal cross-section with MR = 1.85 Tenacity of yarn, as produced, was 2.2 gm/denier. 25 Two ends were twisted at 4.75 twists/inch and heatset to stabilize twisted structure prior to tufting and finishing to produce 1 0 th gauge, 0.22 inch pile height 5 carpet having a basis weight of approximately 24 oz/sq. yd. The carpet tested for wear had the following ratings: Hexapod (ASTM D5252) 4.0 after 4000 cycles and 2.3 after 12000 cycles 10 Vetterman Drum(ASTM D5417) 4.7 after 5000 cycles and 2.8 after 22000 cycles. Example 5 Using a spinning arrangement as shown in Figure 2B bio-based poly-trimethylene terephthalate polymer 15 having an intrinsic viscosity of 1.02 and less than 50 ppm moisture was spun through a 70-hole spinneret of present invention with following dimensions (Figure 2B): C = 0.0028 inch, D = 0.0222 inch, 20 H = 0.0139 inch, Modification ratio MR = 1.8 The temperature set points for downstream barrels of a single screw extruder, transfer line, pumps, pack and die were in the range of 245-260'C. The spinning throughput 25 was 385 grams per minute. The molten filaments were cooled in the chimney, where the 17'C air was blown past the filaments. Filaments were pulled by a pair of feed rolls at 50'C at a surface speed of 1180 meters per minute through the quench zone. Filaments were coated with a 30 lubricant immediately prior to the feed roll. The coated filaments were pre-drawn by a ratio of 1.008 by a pair of rolls at 55'C with a surface speed of 1190 meters per minute. The filaments were then drawn by a ratio of 2.52 and annealed by another pair of heated draw rolls at 160'C 35 running at a surface speed of 3000 meters per minute. The filaments were texturized using a stuffer-jet bulker with jet air temperature at 205 'C, interlaced and wound at 2435 meters per minute. 26 Filaments produced had the following properties: Denier per filament = approximately 20 a = 0.00085 inch b = 0.00029 inch 5 c = 0.00091 inch MR = 1.41 Tenacity of yarn, as produced, was 2.20 gm/denier.Two ends were twisted at 4.75 twists/inch and heatset to stabilize twisted structure prior to tufting and finishing 10 to produce 1 0 th gauge, 0.22 inch pile height carpet having a basis weight of approximately 24 oz/sq. yd. The carpet tested for wear had the following ratings: Hexapod (ASTM D5252) 15 4.5 after 4000 cycles and 3.7 after 12000 cycles Vetterman Drum (ASTM D5417) 4.5 after 5000 cycles and 3.5 after 22000 cycles. Example 6 Using a spinning arrangement as shown in 20 Figure 2B bio-based poly-trimethylene terephthalate polymer having an intrinsic viscosity of 1.02 and less than 50 ppm moisture was spun through a 70-hole spinneret of present invention with following dimensions (Figure 2A): A = 0.0759 inch, 25 B = 0.0637 inch, C = 0.0032 inch, D = 0.0222 inch, Modification ratio MR = 2.4 The temperature set points for downstream barrels of a 30 single screw extruder, transfer line, pumps, pack and die were in the range of 245-260'C. The spinning throughput was 385 grams per minute. The molten filaments were cooled in the chimney, where the 17'C air was blown past the filaments. Filaments were pulled by a pair of feed rolls 35 at 50'C at a surface speed of 1180 meters per minute through the quench zone. Filaments were coated with a lubricant immediately prior to the feed roll. The coated filaments were pre-drawn by a ratio of 1.008 by a pair of 27 rolls at 55'C with a surface speed of 1190 meters per minute. The filaments were then drawn by a ratio of 2.52 and annealed by another pair of heated draw rolls at 160'C running at a surface speed of 3000 meters per minute. The 5 filaments were texturized using a stuffer-jet bulker with jet air temperature at 205 'C, interlaced and wound at 2435 meters per minute. Filaments produced had the following properties: Denier per filament = approximately 20 10 a = 0.00087 inch b = 0.00033 inch c = 0.00084 inch MR = 1.43 Tenacity of yarn, as produced, was 1.95 15 gm/denier. Two ends were twisted at 4.75 twists/inch and heatset to stabilize twisted structure prior to tufting and finishing to produce 1 0 th gauge, 0.22 inch pile height carpet having a basis weight of approximately 24 oz/sq. yd. 20 The carpet tested for wear had the following ratings: Hexapod (ASTM D5252) 4.5 after 4000 cycles and 3.7 after 12000 cycles Vetterman Drum (ASTM D5417) 25 4.5 after 5000 cycles and 3.8 after 22000 cycles. Fibrillation-resistant behavior of the cross section of a filament in accordance with the present invention is further exemplified by comparison of the wear performance 30 of carpets in Examples 5 and 6 of the present invention with a typically used trilobal cross-section described in Example 4. Both Hexapod and Vetterman drum tests showed superior long-term performance (12000 cycles and 22000 cycles, respectively) of carpets made in accordance with 35 the present invention. As shown in Table 1 below, the "Difference" between the values for both the Hexapod and Vetterman Drum tests for Examples 5 and 6 of the present invention at the 12000 and 22000 cycle test points were 28 higher than the "Differences" for Example 4 (Comparative) at the same 12000 and 22000 cycle test points. These data indicate better fibrillation resistance for Examples 5 and 6 than for Example 4. 5 Table 1 Ex. Hexapod Hexapod Difference Vetterman Vetterman Difference No. 4000 12000 for Hexapod Drum Drum For Vetterman cycles Cycles (Q - R) 5000 Cycles 22000 Cycles Drum (Q) (R) (X) (Y) (X - Y) 4 (Comp) 4.0 2.3 1.7 4.7 2.8 1.9 5 4.5 3.7 0.8 4.5 3.5 1.0 6 4.5 3.7 0.8 4.5 3.8 0.7 Where the terms "comprise", "comprises", "comprised" or "comprising" are used in this specification, they are to be 10 interpreted as specifying the presence of the stated features, integers, steps or components referred to, but not to preclude the presence or addition of one or more other feature, integer, step, component or group thereof. 29