US20190055671A1

US20190055671A1 - Process for forming synthetic fiber and fiber, yarns and carpets produced thereby

Info

Publication number: US20190055671A1
Application number: US15/752,674
Authority: US
Inventors: Sundar Mohan Rao
Original assignee: Individual
Current assignee: Invista North America LLC
Priority date: 2015-04-17
Filing date: 2016-04-18
Publication date: 2019-02-21
Also published as: EP3307929A4; WO2016168807A1; EP3307929A1

Abstract

Processes for forming synthetic fibers from polymer melts containing a first fiber forming polymer, a spin assist additive, and optionally a pigment additive are provided. Also provided are synthetic fibers of a first fiber forming polymer, a spin assist additive, and optionally a pigment additive, as well as articles of manufacture such as yarns, carpets and fabrics made up of these synthetic fibers.

Description

FIELD OF INVENTION

The present disclosure relates to extrusion and spinning processes for forming synthetic fibers from polymer melts comprising a first fiber forming polymer, a spin assist additive, and an optional pigmented additive. The present disclosure also relates to synthetic fibers comprising a first fiber forming polymer, a spin assist additive, and optionally a pigmented additive, as well as articles of manufacture such as yarns, carpets and fabrics comprising these synthetic fibers.

BACKGROUND

Use of solution dyed nylon (SDN) fibers as a replacement for white yarns is increasing in both residential and commercial textile markets. One problem that continues to hamper the broader use of SDN fibers is the relative difficulty in spinning fiber from SDN polymer, due to increased nucleation caused by the pigments used to color the spun fiber. SDN yarns are more difficult to draw, and this outcome produces poor yields for many pigmented SDN fibers. This problem is more severe when using hard to spin pigments, examples of which include, but are not limited to, Pigment Green 70, Pigment Red 81, and Pigment Red 67, and while spinning yarns with high loading of organic pigments.
To mitigate this problem, nylon copolymers made from monomers such as MPMD, isophthalic acid (I) and 5-sulfoisophthalic acid (SIPA) have been used. See U.S. Pat. No. 5,422,420, U.S. Pat. No. 5,290,850 and U.S. Pat. No. 5,223,196.
In addition, U.S. Pat. No. 3,926,924 discloses a ternary fiber-forming copolyamide for use in apparel fabrics consisting of at last 50% by weight hexamethylene adipamide, 20-40 percent by weight hexamethylene terephthalamide and 2-20 percent by weight of a third polyamide such as polyepsilon caprolactam (nylon 6), polyhexamethylene isophthalamide (nylon 6I), polyhexamethylene sebacamide (nylon 6,10), polyhexamethylene suberamide (nylon 6,8) or poly(a-amino undecanoic acid) (nylon 11).
U.S. Pat. No. 4,238,603 discloses fiber-forming polymers prepared from a mixture of the hexamethylene diamine salts of terephthalic acid, isophthalic acids, and a smaller amount of at least one aliphatic dibasic acid having 5 to 12 carbon atoms.
U.S. Pat. No. 5,185,428 discloses a copolyadipamide consisting of between 60 and 99.5 mole percent hexamethylene adipamide units and between about 0.5 and 40 mole percent pentamethylene adipamide units, also referred to nylon 66/56.
U.S. Pat. No. 5,194,578 discloses a copolyamide consisting of between 60 and 99.5 mole percent hexamethylene adipamide units and between about 0.5 and 40 mole percent 2-methyl-pentamethylene adipamide units, also referred to nylon 66/Me5-6.
Accordingly, there is a need for processes for producing SDN fibers with improved yields which will enable improved productivity in manufacturing and lower costs of products made from such SDN fibers.

SUMMARY OF THE INVENTION

An aspect of the present invention relates to a process for forming a synthetic fiber. In this process, a polymer melt comprising a first fiber forming polymer, a spin assist additive, and a pigment additive is produced and a synthetic fiber is formed from the polymer melt.
In one nonlimiting embodiment, the spin assist additive is present in a range from about 0.5 to about 5 percent by weight.
In one nonlimiting embodiment, the spin assist additive is a polyamide comprising at least one aliphatic diamine and at least two distinct aromatic dicarboxylic acids, and copolymers and blends thereof.
In one nonlimiting embodiment, the pigment additive is present in a range from about 0.01 to about 5 percent by weight.
Another aspect of the present invention relates to a synthetic fiber comprising a first fiber forming polymer, a spin assist additive and a pigment additive.
In one nonlimiting embodiment, the spin assist additive is present in the synthetic fiber at a range from about 0.5 to about 5 percent by weight.
In one nonlimiting embodiment, the spin assist additive is a polyamide comprising at least one aliphatic diamine and at least two distinct aromatic dicarboxylic acids, and copolymers and blends thereof.
In one nonlimiting embodiment, the pigment additive is present in the synthetic fiber at a range from about 0.01 to about 5 by weight.
Another aspect of the present invention relates to an article of manufacture comprising one or more synthetic fibers of the present invention. In one nonlimiting embodiment, the article of manufacture is a yarn formed from one or more synthetic fibers of the present invention. In another nonlimiting embodiment, the article of manufacture is a carpet comprising yarns formed from one or more synthetic fibers of the present invention. In another nonlimiting embodiment, the article of manufacture is a fabric formed from one or more synthetic fibers of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to polymer additives which improve the spinnability of solution dyed nylon (SDN) fibers. Accordingly, provided by the present invention are processes for production of these synthetic fibers, synthetic fibers produced comprising these polymer additives, and articles of manufacture comprising one or more of these synthetic fibers.

Abbreviations and Definitions

BF—broken filament
D—methylpentamethylene diamine
DP—differential pressure: the pressure difference measured at either end of a spin pack positioned upstream of a spinneret
I—isophthalic acid
MPMD—methylpentamethylene diamine
RV—relative viscosity, as is commonly understood in the trade and as can be determined by ASTM D789.
SDN—solution dyed nylon
SIPA—5-sulfoisophthalic acid
Fiber—as used herein, the term fiber refers to one or more extruded filaments. The fibers in the disclosure may refer to staple fibers, continuous fibers, textile fibers or monofilaments.
In the processes of the present invention, a polymer melt comprising a first fiber forming polymer and a spin assist additive is produced.
Examples of first fiber forming polymers useful in the processes of the present invention include, but are not limited to, polyamides, polyesters, polyolefins and combinations thereof. In one nonlimiting embodiment, the first fiber forming polymer is polyethylene terephthalate. The polyamide may be selected from the list consisting of nylon 6; nylon 6,6; nylon 4,6; nylon 6,12; nylon 6,10;; nylon 7; nylon 11; and nylon 12; and blends and copolymers thereof. In one nonlimiting embodiment, the first fiber forming polymer is nylon 6,6.
In one nonlimiting embodiment, the first fiber forming polymer is present in a range from about 75 to about 99 percent by weight.
Prior disclosed use for several of the polymers found by the inventors herein to be useful as spin assist additives was for making injection molded articles, and transparent nylon films. Thus, efficacy of these additives as spin assist additives in the production of nylon fiber is unexpected. Spin assist additives useful in the present invention include polyamides comprising at least one aliphatic diamine and at least two distinct aromatic dicarboxylic acids, and copolymers and blends thereof. Examples include, but are not limited to, polyamides comprising at least one aliphatic diamine, and at least one aromatic dicarboxylic acid. Suitable diamines are selected from a group consisting of 2-methyl-1,5-pentamethylene diamine, hexamethylene diamine, 2-methyl hexamethylene diamine, 3-methyl hexamethylene diamine, 2,5-dimethyl hexamethylene diamine, 2,2-dimethylpentamethylene diamine, 5-methylnonane diamine, dodecamethylene diamine, 2,2,4- and 2,4,4-trimethyl hexamethylene diamine, 2,2,7,7-tetramethyl octamethylene diamine and diaminodicyclohexyl methane. Suitable aromatic diacids are selected from a group consisting of terephthalic acid, isophthalic acid and naphthalene dicarboxylic acid and 5-sulfoisophthalic acid.
The spin additive may also further comprise aliphatic dicarboxylic acids and polyamides formed from the aliphatic diamines and aliphatic dicarboxylic acids. Suitable aliphatic dicarboxylic acids include, but are not limited to succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid and sebacic acid. In one nonlimiting embodiment, the aliphatic dicarboxylic acid is adipic acid.
In one nonlimiting embodiment, the spin assist additive is selected from the group consisting of nylon DT, nylon DI, nylon 6I, nylon 6T, nylon 6, nylon 6,6, and copolymers and blends thereof.
In one nonlimiting embodiment, the spin assist additive is a composition comprising a copolyamide containing about 40 to about 80 mol % 2-methyl-1,5-pentamethylene terephthalamide (“DT”) repeat units, and about 20 to about 60 mol % 2-methyl-L5-pentamethyleneisophthalamide (“DI”) repeat units. In another nonlimiting embodiment, the copolyamide has a relative viscosity (“RV”) of at least 1.90.
In one nonlimiting embodiment, the spin assist additive is present in a range from about 0.5 to about 5 percent by weight. In another nonlimiting embodiment, the spin assist additive is present in a range from about 0.5 to about 5 percent by weight.
In some embodiments of the present invention, a pigment additive is also added to the polymer melt. For purposes of the present invention, by pigment or pigment additive, it is meant to be inclusive, but is not limited to, a color pigment of one of the three families of the trichromatic dye color system (blues, yellows, reds) that can be added to a polymeric fiber in an amount effective to reduce the L* value of the fiber over a non-color pigmented fiber. It is also meant to be inclusive of green pigments such as Green 70, also known as Pigment Green 7. Preferable color pigments are stable in light (color fast). As those well versed in the art will note, the trichromatic color system is widely practiced in the fiber dyeing industry. In this invention, the color pigments belong to this color system of blues, reds and yellows. In one nonlimiting embodiment, the pigment additive is an organic pigment. Nonlimiting examples of pigment additives useful in the present invention include, red pigments such as Pigment Red 60, Pigment Red 63, Pigment Red 80, Pigment Red 66, Pigment Red 67, Pigment Red 81, Pigment Red 68, Pigment Red 73, and Pigment Red 83, Yellow pigments such as Pigment Yellow 65, Pigment Yellow 82, Pigment Yellow 85, and Pigment yellow 87, Blue pigments such as Pigment Blue 61, Pigment Blue 69, Pigment Blue 74, Pigment Blue 78, and Green pigments such as Green 70, also known as Pigment Green 7.
In one nonlimiting embodiment, the pigment additive is present in a range from about 0.01 to about 5 percent by weight.
In one nonlimiting embodiment, the polymer melt is produced by drying or polymerizing via solid phase the first fiber forming polymer to a desired relative viscosity (RV) and feeding the dried or polymerized first fiber forming polymer into extruder for remelting and spinning. In embodiments comprising a pigment additive, pigment concentrates are added through feeders at the throat of extruder at desired rates to make a given colored yarn. In one embodiment, the spin assist additive is added, preferably as a pellet, at the extruder throat at the rate of 0.5% to 5%. In another embodiment, the spin assist additive is extruded in separate extruder and fed as melt stream into a transfer line carrying molten base first fiber forming polymer. In this embodiment, mixing of spin assist additive in molten form is preferably accomplished with a twin screw extruder, and supplemented by suitable static mixers in the transfer line.
The synthetic fibers are then formed from the polymer melt. In one nonlimiting embodiment, the polymer melt is extruded through a spinneret to form one or a plurality of filaments. The one or a plurality of filaments are then drawn to form a synthetic fiber. In one nonlimiting embodiment, the fiber is drawn at a draw ratio of 2.65 or higher. In one nonlimiting embodiment, the number of broken filaments observed in a two minute interval while drawing the one or a plurality of filaments to form a synthetic fiber is less than 10. In another nonlimiting embodiment, the number of broken filaments observed in a two minute interval while drawing the one or a plurality of filaments to form a synthetic fiber is less than 5.
The method of the current invention can also be used to form polymer melts that can be extruded for other purposes. For example a polymer melt comprising a first polymer and an extrusion assist additive can be extruded in an additive printing machine (3D printing). Suitable polymers include, but are not limited to nylon 6; nylon 6,6; nylon 4,6; nylon 6,12; nylon 6,10; nylon 6T; nylon 6I; nylon 9T; nylon DT; nylon DI; nylon D6; nylon 7; nylon 11; and nylon 12; and blends and copolymers thereof. Suitable extrusion assist additives include polyamides comprising at least one aliphatic diamine and at least two distinct aromatic dicarboxylic acids, and copolymers and blends thereof. Examples include, but are not limited to, polyamides comprising at least one aliphatic diamine selected from a group consisting of 2-methyl-L5-pentamethylene diamine, hexamethylene diamine, 2-methyl hexamethylene diamine, 3-methyl hexamethylene diamine, 2,5-dimethyl hexamethylene diamine, 2,2-dimethylpentamethylene diamine, 5-methylnonane diamine, dodecamethylene diamine, 2,2,4- and 2,4,4-trimethyl hexamethylene diamine, 2,2,7,7-tetramethyl octamethylene diamine and diaminodicyclohexyl methane and polyamides comprising aromatic dicarboxylic acids are selected from a group consisting of terephthalic acid, isophthalic acid and naphthalene dicarboxylic acid and 5-sulfoisophthalic acid. In one nonlimiting embodiment, the extrusion assist additive is selected from the group consisting of nylon DT/DI, nylon DT/6I, nylon DI/6T, nylon 6T/6I, nylon DT/DI/D6, nylon 6T/6I/66 and copolymers and blends thereof.
Also provided by the present invention are synthetic fibers comprising a first fiber forming polymer and a spin assist additive.
Examples of first fiber forming polymers used in these synthetic fibers of the present invention include, but are not limited to, polyamides, polyesters, polyolefins and combinations thereof. In one nonlimiting embodiment, the first fiber forming polymer is polyethylene terephthalate. The polyamide may be selected from the list consisting of nylon 6; nylon 6,6; nylon 4,6; nylon 6,12; nylon 6,10; nylon 6T; nylon 6I; nylon 9T; nylon DT; nylon DI; nylon D6; nylon 7; nylon 11; and nylon 12; and blends and copolymers thereof. In one nonlimiting embodiment, the first fiber forming polymer is nylon 6,6.
In one nonlimiting embodiment, the first fiber forming polymer is present in a range from about 75 to about 99 percent by weight.
Prior disclosed use for several of the polymers found by the inventors herein to be useful as spin assist additives was for making injection molded articles, transparent nylon films, etc. Thus, efficacy of these additives as spin assist additives in the production of nylon fiber is unexpected. Spin assist additives used in the fibers of the present invention include polyamides comprising at least one aliphatic diamine and at least two distinct aromatic dicarboxylic acids, and copolymers and blends thereof. Examples include, but are not limited to, polyamides comprising at least one aliphatic diamine selected from a group consisting of 2-methyl-L5-pentamethylene diamine, hexamethylene diamine, 2-methyl hexamethylene diamine, 3-methyl hexamethylene diamine, 2,5-dimethyl hexamethylene diamine, 2,2-dimethylpentamethylene diamine, 5-methylnonane diamine, dodecamethylene diamine, 2,2,4- and 2,4,4-trimethyl hexamethylene diamine, 2,2,7,7-tetramethyl octamethylene diamine and diaminodicyclohexyl methane and polyamides comprising aromatic dicarboxylic acids are selected from a group consisting of terephthalic acid, isophthalic acid and naphthalene dicarboxylic acid. In one nonlimiting embodiment, the spin assist additive is selected from the group consisting of nylon DT/DI, nylon DT/6I, nylon DI/6T and nylon 6T/6I, and copolymers and blends thereof.
In one nonlimiting embodiment, the spin assist additive is nylon DT/DI, a composition comprising a copolyamide containing about 40 to about 80 mol % 2-methyl-L5-pentamethyleneterephthalamide (“MPMD-T”) units and about 20 to about 60 mol % 2-methyl-1,5-pentamethyleneisophthalamide (“MPMD-I”) units. In another nonlimiting embodiment, the copolyamide has a relative viscosity (“RV”) of at least 1.90.
In one nonlimiting embodiment, the spin assist additive is present in a range from about 0.5 to about 5 percent by weight.
In one nonlimiting embodiment, the spin assist additive is present in a range from about 0.5 to about 20 percent by weight. In another nonlimiting embodiment, the spin assist additive is present in a range from about 0.5 to about 5 percent by weight.
In some embodiments of the synthetic fibers of the present invention, a pigment additive is added. For purposes of the present invention, by pigment additive, it is meant to be inclusive, but is not limited to, a color pigment of one of the three families of the trichromatic dye color system (blues, yellows, reds) that can be added to a polymeric fiber in an amount effective to reduce the L* value of the fiber over a non-color pigmented fiber. It is also meant to be inclusive of green pigments such as Green 70 also known as Pigment Green 7. Preferable color pigments are stable in light (color fast). As those well versed in the art will note, the trichromatic color system is widely practiced in the fiber dyeing industry. In this invention, the color pigments belong to this color system of blues, reds and yellows. In one nonlimiting embodiment, the pigment additive is an organic pigment. Nonlimiting examples of pigment additives useful in the present invention include, red pigments such as Pigment Red 60, Pigment Red 63, Pigment Red 80, Pigment Red 66, Pigment Red 67, Pigment Red 81, Pigment Red 68, Pigment Red 73, and Pigment Red 83, Yellow pigments such as Pigment Yellow 65, Pigment Yellow 82, Pigment Yellow 85, and Pigment yellow 87, Blue pigments such as Pigment Blue 61, Pigment Blue 69, Pigment Blue 74, Pigment Blue 78, and Green pigments such as Green 70 also known as Pigment Green 7.
In one nonlimiting embodiment, the pigment additive is present in a range from about 0.01 to about 5 percent by weight.
In addition, the present invention provides articles of manufacture, at least a portion of which comprising a synthetic fiber of the present invention. Nonlimiting examples of articles of manufacture of the present invention include yarns formed from one or more of the synthetic fibers, carpet formed from these yarns, as well as fabric formed from one or more these synthetic fiber.
Without being bound to any particular theory, it is believed that due to diminished nucleation and crystallinity, and improved clarity, the dyed and pigments articles, including yarns, fibers, filaments, and extruded microfilaments, produced from compositions disclosed here will have a brighter, more attractive appearance. In white yarns, the process of the present invention are expected to yield deeper dyeing yarns (higher dye strike rate). Further, using a spin assist additive in accordance with the present invention is expected to improve yields and enable improved productivity in manufacturing thereby lowering costs.
The following section provides further illustration of the fabrics of this invention. These working examples are illustrative only and are not intended to limit the scope of the invention in any way.

EXAMPLES

Example 1

Test Methods

Test methods used to evaluate the synthetic fibers and yarns produced in accordance with the methods of the present invention included:
Draw ratio-to-break test: In this test, the draw ratio, which is the ratio of chest roll speed to feed roll speed, is increased till the break of yarn is observed. That ratio-to-break is an indication of the effectiveness of spin assist additive.
Draw tension test: Yarn draw tension is measured between the feed roll and the draw roll. In general, a lower draw tension indicates improved spinnability.
The spinning performance was measured by broken filaments/2 minutes. The number of broken filaments was observed by counting the number of flashes observed during the yarn spinning process. Each flash correlated to a broken filament.

Example 2

1245 Denier BCF Pigmented Yarns Extrusion

A 1245 denier, 68 filament, 4-hole hollowfil, nylon 6,6 yarn was made according to a process well known in the art. Nylon 6,6 copolymer flake was conditioned to the desired RV, and fed into a twin screw extruder running at 190 rpm and a temperature profile of 230° C. at the feed and 285° C. at the discharge. The melted polymer was passed through a heated transfer line, spinning pump and filter pack and then to a spinneret which formed the polymer into individual filaments. The total time that the mixture spent in the melt phase was approximately 8 minutes. The filaments were air quenched and then passed by a touch roller where a suitable finish was applied. The finished filaments were then converged in a yarn bundle which was subsequently drawn, passed over heated rolls, bulk textured according the bulk texturing process described by Coon in U.S. Pat. No. 3,525,134, relaxed, and wound onto tubes. The nylon 6,6 base copolymer was then conditioned to 195° C. and remelted using a twin screw extruder. Control fiber (i.e. fiber spun without any additives), and additives nylon DT/6I, nylon DT/DI and nylon 6T/6I were premixed with base nylon, and fed into the extruder. The pigment concentrates and additives were fed through K-tron feeders and BCF yarn was spun using standard procedures.

Example 3

1245 Denier BCF Pigmented Yarns

A 1245 denier, 68 filament, 4-hole hollowfil, nylon 6,6 yarn was made according to a process well known in the trade: nylon 6,6 flake was fed into a twin screw extruder running at 190 rpm and a temperature profile of 230° C. at the feed and 285° C. at the discharge. The melted polymer was passed through a heated transfer line, spinning pump and filter pack and then to a spinneret which formed the polymer into individual filaments. The total time that the mixture spent in the melt phase was approximately 8 minutes. The filaments were air quenched and then passed by a touch roller where a suitable finish was applied. The finished filaments were then converged in a yarn bundle which was subsequently drawn, passed over heated rolls, bulk textured according the bulk texturing process described by Coon in U.S. Pat. No. 3,525,134, relaxed and wound onto tubes.
The yarns spun are shown in Table 1.

TABLE 1

							Draw Tension @
		Loading		Additive Feed		Feed Roll	DR = 2.65	yarn	Chest Roll
Item	Color	ppm	Additive	rate, ppm	DP	Wrap	(Front TL Only)	needed	Speed

2A	Red 81-	4000	None	NA	880	x	1250	1 doff	2425
	25%
2B	Red 81-	4000	nylon	15,000	878	x	1250	1 doff	2425
	25%		DT/6I
2C	Red 81-	4000	nylon	30,000	790	x	1250	1 doff	2425
	25%		DT/6I
2D	Red 81-	4000	nylon	15,000	890	x	1250	1 doff	2425
	25%		DT/DI
2E	Red 81-	4000	nylon	30,000	875	x	1250	1 doff	2425
	25%		DT/DI
2F	Red 81-	4000	nylon	15,000	875	x	1250	1 doff	2425
	25%		6T/6I
2G	Red 81-	4000	nylon	30,000	880	x	1250	1 doff	2425
	25%		6T/6I

Draw ratio-to-break tests were performed on these yarns. In these tests, the draw ratio (DR) was varied till the yarn broke. The higher the draw ratio to break, the more robust is the yarn spinning. In addition, the number of flashes seen in hot chest roll over a 2 minute period was recorded for each draw ratio. The lower this number, the more robust is the spinning process. This data is shown in Table 2.

TABLE 2

DR = 2.65	DR = 2.70	DR = 2.80	DR = 2.90	DR = 3.0	DR = 3.1	DR = 3.2

Item

Color

BF

2A	Red 81-	915	24	898		866		836		808		782		758
	25%
2B	Red 81-	915	6	898	4	866	4	836	0	808	1	782	4	758	15
	25%
2C	Red 81-	915	2	898	7	866	1	836	0	808	4	782	2	758	3
	25%
2D	Red 81-	915	3	898	2	866	6	836	2	808	0	782	4	758	2
	25%
2E	Red 81-	915	0	898	1	866	0	836	0	808	0	782	0	758	0
	25%
2F	Red 81-	915	4	898	0	866	2	836	2	808	0	782	0	758	1
	25%
2G	Red 81-	915	0	898	0	866	0	836	0	808	1	782	1	758	0
	25%

*BF represents the number of observed flashes in a 2 minute interval. Each flash is understood to represent a broken filament.

The pigment additive used in these yarns was Red-81 which is difficult to spin. As shown in Table 2, control yarn without spin assist additive had high broken filaments in 2 minutes even at a draw ratio of 2.65. Control yarn could not be spun at any higher draw ratio. However, when using spin assist additives nylon 6T/6I and nylon DT/DI, (see items 2D, 2E, 2F and 2G), fibers could be spun without significant broken filaments even at draw ratios as high as 3.20. This indicates that the spin performance in a commercial machine would be much better upon addition of spin assist additive agents in accordance with the present invention.

Claims

1. A process for forming a synthetic fiber, said process comprising the steps of:

(a) producing a polymer melt comprising a first fiber forming polymer and a spin assist additive, wherein the spin assist additive is present in a range from about 0.5 to about 5 percent by weight; and

(b) forming a synthetic fiber from the polymer melt.

2. The process of claim 1, wherein the spin assist additive is a polyamide comprising at least one aliphatic diamine and at least two distinct aromatic dicarboxylic acids, and copolymers and blends thereof.

3. The process of claim 2, wherein the at least one aliphatic diamine is selected from a group consisting of 2-methyl-1,5-pentamethylene diamine, hexamethylene diamine, 2-methyl hexamethylene diamine, 3-methyl hexamethylene diamine, 2,5-dimethyl hexamethylene diamine, 2,2-dimethylpentamethylene diamine, 5-methylnonane diamine, dodecamethylene diamine, 2,2,4- and 2,4,4-trimethyl hexamethylene diamine, 2,2,7,7-tetramethyl octamethylene diamine and diaminodicyclohexyl methane.

4. The process of claim 2, wherein the aromatic dicarboxylic acids are selected from a group consisting of terephthalic acid, isophthalic acid and naphthalene dicarboxylic acid.

5. The process of claim 2, wherein the spin assist additive is selected from the group consisting of nylon DT/DI, nylon DT/6I, nylon DI/6T and nylon 6T/6I, and copolymers and blends thereof.

6. (canceled)

7. (canceled)

8. The process of claim 1, wherein the first fiber forming polymer is selected from the group consisting of a polyamide, polyester, polyolefin and combinations thereof.

9. The process of claim 8, wherein the first fiber forming polymer is polyethylene terephthalate or nylon-6,6.

10. (canceled)

11. The process of claim 1 further comprising addition of a pigment additive to the polymer melt, wherein the pigment additive is an organic or inorganic pigment and the pigment is present in a range from about 0.01 to about 5 percent by weight.

12. (canceled)

13. (canceled)

14. The process of claim 1, wherein forming a synthetic fiber comprises extruding said polymer melt through a spinneret to form one or a plurality of filaments, and drawing the one or a plurality of filaments to form a synthetic fiber.

15. The process of claim 14, wherein the fiber can be drawn at a draw ratio of 2.65 or higher.

16. The process of claim 15, wherein the number of broken filaments observed in a two minute interval while drawing the one or a plurality of filaments to form a synthetic fiber is less than 10.

17. A synthetic fiber comprising:

(a) a first fiber forming polymer; and

(b) a spin assist additive present in the synthetic fiber at a range from about 0.5 to about 5 percent by weight, wherein the spin assist additive is a polyamide comprising at least one aliphatic diamine and at least two distinct aromatic dicarboxylic acids, and copolymers and blends thereof.

18. (canceled)

19. The synthetic fiber of claim 17, wherein the at least one aliphatic diamine is selected from a group consisting of 2-methyl-1,5-pentamethylene diamine, hexamethylene diamine, 2-methyl hexamethylene diamine, 3-methyl hexamethylene diamine, 2,5-dimethyl hexamethylene diamine, 2,2-dimethylpentamethylene diamine, 5-methylnonane diamine, dodecamethylene diamine, 2,2,4- and 2,4,4-trimethyl hexamethylene diamine, 2,2,7,7-tetramethyl octamethylene diamine and diaminodicyclohexyl methane.

20. The synthetic fiber of claim 17, wherein the aromatic dicarboxylic acids is selected from a group consisting of terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid and 5-sulfoisophthalic acid.

21. The synthetic fiber of claim 17, wherein the spin assist additive is selected from the group consisting of DT/DI, DT/6I, DI/6T and 6T/6I, and copolymers and blends thereof.

22. (canceled)

23. (canceled)

24. The synthetic fiber of claim 21, wherein the spin assist additive does not substantially copolymerize with the first fiber forming polymer.

25. The synthetic fiber of claim 17, wherein the first fiber forming polymer is selected from the group consisting of a polyamide, polyester, polyolefin and combinations thereof.

26. The synthetic fiber of claim 25, wherein the first fiber forming polymer is selected from polyethylene terephthalate and nylon-6,6.

27. (canceled)

28. (canceled)

29. (canceled)

30. (canceled)

31. An article of manufacture comprising the synthetic fiber of claim 26.

32. (canceled)

33. (canceled)

34. (canceled)