US20150176160A1

US20150176160A1 - Woven and knitted fabrics with improved properties and core spun yarns for producing the same

Info

Publication number: US20150176160A1
Application number: US14/607,090
Authority: US
Inventors: Ivy Sau Chun LEE; Michael Xiao Li WANG; Frances WU; John Ying Bun WU
Original assignee: Best Key Textiles Ltd
Current assignee: Best Key Textiles Ltd
Priority date: 2011-10-24
Filing date: 2015-01-28
Publication date: 2015-06-25

Abstract

A woven or knitted fabric with improved properties is formed of core spun yarns each including (i) a core draw textured yarn (DTY) consisting of a core material of polyethylene terephthalate (PET); and (ii) a wrapper of cotton staple fibers, polyester staple fibers, rayon staple fibers, modal staple fibers, fire retardant staple fibers or a blend thereof. The fabric may be produced by ring spun, open-end or vortex. The fabric may be produced by different weaving and knitting methods. Regular yarns are mixed in the fabric.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a Continuation-In-Part Application of U.S. patent application Ser. No. 13/655,422 filed on Oct. 18, 2012, which claims priority of U.S. provisional patent application No. 61/550,464 filed on Oct. 24, 2011, the entire content of which is hereby incorporated by reference.

FIELD OF THE TECHNOLOGY

The present application relates to woven and knitted fabrics with improved tensile and tear strength properties, improved abrasion resistance properties, and natural and permanent wrinkle resistance properties. The present application also relates to core spun yarns for producing the woven and knitted fabrics with the improved properties.

BACKGROUND

In order to increase tensile and tear strength, heavier fabrics with thicker and heavier yarns are usually utilized. These fabrics are thicker and heavier to meet the strength requirements. As a result, these fabrics tend to cause much discomfort to the wearer of the apparel, particularly in summer months.
The wrinkle resistant properties of a fabric are normally achieved with the application of resins containing, among other chemicals, formaldehyde and then curing by heat. However, the rating of wrinkle resistance will deteriorate as the apparel is repeatedly laundered. Furthermore, formaldehyde has been classified by the National Institutes of Health as being a carcinogen.
In order to increase abrasion resistance, heavier fabrics with thicker and heavier yarns are also utilized. These fabrics are thicker and heavier to meet the requirements. Again, as a result, these fabrics tend to cause much discomfort to the wearer of the apparel, particularly in the summer months.
Furthermore, the cost of these thicker and heavier fabrics is necessarily increased due to the use of more materials.
Hence, there is a need to produce woven and knitted fabrics with improved properties.
The above description of the background is provided to aid in understanding woven/knitted fabrics and core spun yarns, but is not admitted to describe or constitute pertinent prior art to the woven/knitted fabrics and core spun yarns disclosed in the present application, or consider any cited documents as material to the patentability of the claims of the present application.

SUMMARY

According to one aspect, there is provided a core spun yarn including a core yarn and a wrapper wrapping around the core yarn. The core yarn includes a core draw textured yarn (DTY) consisting of a core material of polyethylene terephthalate (PET). The wrapper includes a wrap material selected from the group consisting of 100% cotton staple fibers, polyester cotton blended staple fibers, 100% polyester staple fibers, 100% rayon staple fibers, 100% modal staple fibers, 100% fire retardant staple fibers, polyester rayon blended staple fibers and cotton rayon blended staple fibers and blends thereof.
In one embodiment, a diameter of the DTY is in a range of 20-50D.
According to another aspect, there is provided a fabric made of a core spun yarn having a core yarn and a wrapper wrapping around the core yarn. The core yarn includes a core draw textured yarn (DTY) consisting of a core material of polyethylene terephthalate (PET). The wrapper includes a wrap material selected from the group consisting of 100% cotton staple fibers, polyester cotton blended staple fibers, 100% polyester staple fibers, 100% rayon staple fibers, 100% modal staple fibers, 100% fire retardant staple fibers, polyester rayon blended staple fibers and cotton rayon blended staple fibers and blends thereof.
In one embodiment, F count of yarn of the fabric is in a range of 24-144.
In one embodiment, the fabric may further include a non-core yarn. The fabric may be formed with a mixture of the core spun yarns and the non-core yarns.
In one embodiment, the ratio of core spun yarns to non-core yarns can be one core spun yarn to one or more non-core yarns.
In one embodiment, the mix of core spun yarns to non-core yarns is one core spun yarn interlaced with one non-core yarn of similar yarn count and blend, and for every inch 64 core spun yarns and 64 non-core yarns are employed as warp yarns, 30 core spun yarns and 30 non-core yarns are employed as weft yarns.
In one embodiment, the fabric may have a weaving configuration selected from the group consisting of poplin weave, poplin rip stop weave, left hand twill 2:1 weave, left hand twill 2:2 weave, left hand twill 3:1 weave, right hand twill 2:1 weave, right hand twill 2:2 weave, right hand twill 3:1 weave, left hand sateen 4:1 weave, right hand sateen 4:1 weave, canvas 1:1 weave, canvas 2:2 weave, oxford 2:2 double ply weave, cavalry weave, dobby weave, jacquard weave, corduroy weave and flannel weave.
In one embodiment, the fabric may have a weft knit configuration selected from the group consisting of jersey, rib 1×1, rib 2×1, rib 2×2, rib 3×3, single pique, double pique, fleece, French terry, interlock, feeder stripe, engineering stripe, dobby and jacquard.
In one embodiment, the fabric may have a warp knit configuration selected from the group consisting of tricot and rachel.
In one embodiment, the fabric can be produced by core spun yarns formed by a core sheath selected from the group consisting of ring spun core sheath, open-end core sheath or vortex core sheath.
According to yet another aspect, there is provided an article of apparel made of the fabric of the present application. The article of apparel may be selected from T shirts, polo shirts, knit shirts, knit shorts, knit pants, knit jackets, woven shirts, woven pants, woven jackets, denim jeans, denim shirts, denim jackets, chambray shirts, yarn dyed shirts, yarn dyed shorts, yarn dyed pants, bed sheets and pillow cases.
In one embodiment, the core spun yarn is produced by wrapping the wrap material around the core material utilizing a ring spin core spun machine. The wrap material includes polyester staple fiber of 1.5 D with 38 mm staple length blended with cotton fiber in a ratio of 74.1% poly/25.9% cotton. The weaving configuration is 3:1 left hand twill and the woven fabric construction is 128 yarns of Ne 20 s/l for warp yarn and 60 yarns of Ne 20 s/l for weft yarn.
In one embodiment, the fabric is sewn into a pair of pants, and the fabric is dyed and then finished.
Although the woven/knitted fabrics and core spun yarns disclosed in the present application are shown and described with respect to certain embodiments, it is obvious that equivalents and modifications will occur to others skilled in the art upon the reading and understanding of the specification. The present application includes all such equivalents and modifications, and is limited only by the scope of the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Specific embodiments of the woven/knitted fabrics and core spun yarns disclosed in the present application will now be described by way of example with reference to the accompanying drawings wherein:

FIG. 1 is a cross sectional view of a core spun yarn according to an embodiment of the present application.

FIG. 2 is a perspective view of a core spun yarn with core and sheath yarns according to another embodiment of the present application.

FIG. 3 is a schematic diagram showing a weaving configuration according to one embodiment of the present application.

FIG. 4 is a schematic diagram showing a weaving configuration according to another embodiment of the present application.

DETAILED DESCRIPTION

Reference will now be made in detail to a preferred embodiment of the woven/knitted fabrics and core spun yarns disclosed in the present application, examples of which are also provided in the following description. Exemplary embodiments of the woven/knitted fabrics and core spun yarns disclosed in the present application are described in detail, although it will be apparent to those skilled in the relevant art that some features that are not particularly important to an understanding of the woven/knitted fabrics and core spun yarns may not be shown for the sake of clarity.
Furthermore, it should be understood that the woven/knitted fabrics and core spun yarns disclosed in the present application is not limited to the precise embodiments described below and that various changes and modifications thereof may be effected by one skilled in the art without departing from the spirit or scope of the appended claims. For example, elements and/or features of different illustrative embodiments may be combined with each other and/or substituted for each other within the scope of this disclosure and appended claims.
As used herein, the term “core yarn” means the internal core member of a yarn, which is normally formed by core spinning. And, as used herein, the term “filament yarn” means a yarn composed of one or more filaments that extend substantially along the entire length of the yarn.
FIG. 1 is a cross sectional view of a core spun yarn 10 according to an embodiment of the present application. The core spun yarn 10 may include a core yarn 11 and a wrapper 12.
The core yarn 11 may include a core material such as polyester filament yarn, mechanical stretch polyester filament yarn, fire retardant polyester filament yarn, spandex filament yarn, high strength polyester filament yarn, nylon filament yarn, mechanical stretch nylon filament yarn, kevlar filament yarn, polypropylene filament yarn or a combination thereof. The filament yarn may include one or more filaments 111.
Furthermore, according to an embodiment, the core yarn is a draw textured yarn (DTY) having a core material of polyethylene terephthalate (PET). DTY is a fully draw, fully oriented polyester multifilament yarn with soft crimp, high bulk and texture with cotton feel and very high durability and retention properties. DTY is suitable for fabric end uses like outer/inner garments, skin-clinging garments, furnishings, upholstery, etc. This is a replacement of cotton and cotton blend yarns with very low moisture content.
In the embodiment, DTY has a core material of polyethylene terephthalate (PET), which is a thermoplastic polymer resin of the polyester family and is used in synthetic fibers.
The selection of core material is based on the desired characteristic of the yarn. For example, if a fire retardant fabric is desired, then a fire retardant polyester filament yarn can be selected. If a high strength fabric is desired, then a high strength polyester filament yarn can be selected. If a fire retardant and high strength fabric is desired, then a combination of fire retardant polyester filament yarn and high strength polyester filament yarn can be selected.
The wrapper 12 can be wrapping around the core yarn 11. The wrapper 12 may include a wrap material such as staple fibers 121. The staple fibers 121 can be 100% cotton staple fibers, polyester cotton blended staple fibers, 100% polyester staple fibers, 100% rayon staple fibers, 100% modal staple fibers, 100% fire retardant staple fibers, polyester rayon blended staple fibers, cotton rayon blended staple fibers or a blend thereof.
FIG. 2 is a perspective view of a core spun yarn 20 according to another embodiment of the present application. This core spun yarn 20 may include a core yarn 21 and a wrapper 22. In this embodiment, the core yarn 21 may have filaments 211 that are closely packed together.
Similarly, the core yarn 21 may include a core material such as polyester filament yarn, mechanical stretch polyester filament yarn, fire retardant polyester filament yarn, spandex filament yarn, high strength polyester filament yarn, nylon filament yarn, mechanical stretch nylon filament yarn, kevlar filament yarn, polypropylene filament yarn or a combination thereof. The filament yarn may include one or more filaments 211.
Again, the wrapper 22 can be wrapping around the core yarn 21. The wrapper 22 may also include a wrap material such as staple fibers 221. The staple fibers 221 can be 100% cotton staple fibers, polyester cotton blended staple fibers, 100% polyester staple fibers, 100% rayon staple fibers, 100% modal staple fibers, 100% fire retardant staple fibers, polyester rayon blended staple fibers, cotton rayon blended staple fibers or a blend thereof.
The method of yarn production may include ring spun, open-end or vortex. Different spinning methods can produce different core sheaths such as ring spun core sheath, open-end core sheath and vortex core sheath. Ring spun, open-end and vortex spinning machines can be used to produce the yarns. A particular spinning method would yield a particular yarn characteristic leading to a particular fabric feature.
According to an embodiment, the core spun yarn including the core draw textured yarn (DTY) consisting of a core material of polyethylene terephthalate (PET) is produced by the following method. At first, polyethylene terephthalate (PET) polyester chips are prepared.

Polyethylene Terephthalate (PET) Polyester Chips

Material Data

	Test conditions
Properties	(Status)	Test Data	Unit

Heat	Melting point		≦248	° C.
	Inherent viscosity		0.85 ± 0.02	dl/g
	Crystallinity		<60	%
	Tinctorial value	L	≧88.9
		b	≦1.4
Others	Ethanal content		≦1.0	ppm
	Dust content		≦30	ppm
	Water		0.01	%
	Diethylene glycol		0.9	%

Process of Polyethylene Terephthalate Polyester Chip-Spinning
1. Drying Process
Primary technical requirements:

Water content of the chip upon drying: <35 ppm
Inherent viscosity of the chip upon drying: <0.02
Equipments: ROSIN drying machine, faux BM drying machine

Conditions:

1) Pre-crystallization temperature: between the glass temperature and the melting point of the chip. Generally controlled within the range of 160˜180 degree Celsius.
2) Pre-crystallization time: 8˜30 minutes, adjusted according to needs.
3) Pre-crystallization air pressure during fluidized bed process: −5˜0 (cmwg)
4) Drying temperature: The higher the temperature, the better the drying effect. However, drastically high temperature may affect the inherent viscosity and color tone of the chip. The temperature is controlled within the range of 160˜185 degree Celsius accordingly.
5) Drying time: controlled within 4˜12(H) generally in order to make the water content of the chip close the average water content.
6) Dry air dew point: The lower the dew point, the better the drying effect. Usually controlled within <−30 degrees Celsius.
7) Dry air pressure: usually controlled within the range of 0.6˜3.3 kgf/cm²

2. Spinning Process
Primary technical requirements: Inherent viscosity of oil-free yarns

Equipments: Barmag from Germany and other domestically produced equipment

Technical Conditions:

1) Sectional temperatures within screw extruder
A: Feeding stage: melting point of the chip +(0˜20) degrees Celsius
B. Compression, metering section temperature: +(10˜40) degrees Celsius
2) Pressure on gauge pin of the screw extruder: It must be ensured that the output of the metering pump is kept constant and that energy consumption is minimized. In general, the pressure is controlled within 8˜12 mpa.
3) Spin manifold temperature: the boiler is heated by means of diphenyl steam so as to ensure the temperature does not decrease and is kept within 285˜298 degrees Celsius.
4) Component pressure: Usually within 12˜28 mpa
5) Pump delivery and rotational speed:

pump delivery (g/min)=spin speed (m/min)*denier of product (dtex)*N/1000
rotational speed of metering pump (RPM)=pump delivery (g/min)/density of melt
(g/cm³)*pump property (cm³/r)*pump efficiency(%)

6) Air cooling
(1) Air speed: excessively high or low air speed will cause uneven rate of increase in fiber strands. Usually kept within 0.3˜0.7 m/s
(2) Air temperature: to ensure the cooling duration of melt jet is not excessively long and minimize the deviation in cooling duration of each monofil. Usually kept within 20˜28 degrees Celsius.
(3) Air humidity (relative humidity): usually kept within 60˜90(%)
(4) Air pressure: usually kept within 450˜600 p.a.

3. Drawing Process:
Determined by product's quality (physical properties and dyeing), production costs and other factors.
In an embodiment, the ring spinning technology is used for producing core-spun yarns. Core-spun spinning is a one of the innovative spinning methods. The yarn is spun with a chemical filament as the core and natural fibers as the wrapping fiber. Low-elastic Draw Textured Yarns (DTY) are used as the core and natural cotton fibers and polyester staple fibers are used as the wrap fibers. By way of addition of a thread guide mechanism and tension control device onto the ring spinning frame, the core-spun spinning mechanism of a ring spinning frame is similar to the conventional spinning mechanism. However, twisting and winding parameters will have a significant effect on core-spun spinning. During twisting, the wrap yarns, which originally should be aligned in parallel with fibers, have to be inclined at a certain angle with the axis. The strand discharged by the front roller contracts gradually and forms a twisting triangular space, within which the number external and internal fiber migration, the relative position between a filament and a staple fiber strand at the front nipper jaws and other factors will have a significant effect on the resultant core-spun yarn.

Example

The motion state of fibers in the twisting triangular space is studied by an example of a core-spun yarn of a combed cotton and polyester blended yarn wrapping a DTY50D/24F filament. The following assumptions are made prior to analysis:

(1) The filament is fed in the middle of the strand
(2) The filament can tolerate sufficiently large tension
(3) The filament is a rigid body

When the yarn is twisted in the Z direction, after the silver and core filament is discharged from the front roller, the strands form a twisting triangular space upon twisting.
As the yarn is twisted, the component force exerted on the fibers generates centrifugal pressure. The pressure is maximum along the edges of the twisting triangular space and minimum around the centre of the yarn axis. Therefore, the peripheral fibers will overcome the resistance between fiber strands and migrate inwards under the influence of the centrifugal pressure. The fibers then become loose instead of strained. On the contrary, the fibers near the centre of the yarn axis migrate outwards due to the squeezing action. Part of the fibers will migrate to the vicinity of the filament, alter its direction of migration out of the resistance exerted by the filament, and eventually move to the position above the filament. The movement renders the filament surrounded by strands of wrapping fibers. Moreover, a fiber strand can undergo multiple migrations within the twisting triangular space. As far as the arrangement of fibers in a yarn is concerned, the fibers do not exist in layers. The spiral line of the fibers in a yarn takes a shape of a cone. This characteristic helps connect fibers in the yarn by external and internal winding, and simultaneously facilitate a tendency to wrap the central filament as the fiber strands contract and form a twisting triangular space.
Addition of a thread guide mechanism and tension control device onto the ring spinning frame for spinning core-spun staple or long fibers has a significant effect on yarn production. By way of altering the height, and width of the twisting triangular space, and the relative position between a filament and strand of staple fibers, the wrapping effect will be significantly improved.
As deduced from the assumption, the filament exists as a rigid body that only gives rise to self-twisting twists but not winding twists. Under these circumstances, the filament remains in the middle of the yarn and hence the wrapping effect is at its best. A core-spun yarn is then formed.
However, when the fibers migrating toward the filament are insufficient, the strands will form a cylindrical yarn before the wrapping fibers enclose the filament. In this sense, the yarns can only be attached spirally on the filament as it is winded. Only the warped wrap yarns contribute to the wrapped twisting. The length of lay inevitably renders the filament exposed.
Factors Affecting the Wrapping Effect of a Core-Spun Yarn
As shown in the analysis above, the factors affecting the wrapping effect of a core-spun yarn include the number of internal and external migration of fibers, the relative position between a continuous filament and strands of short fibers at the front nipper jaws, and others.
The draw textured yarn of polyester filament (55 dtex/36F) produced by Shenghong Group is selected as the core yarn. The properties include a breaking strength of 52.3CN/tex, an elongation at break of 27.4%, a Young's modulus of 332cN/tex. Below shows a variety of choices of core yarns, of which the core yarn in testing is 50D/36F.

Dimensions of core yarns

Dimensions	F count

20D	24F
30D	24F	36F
35D	144F
40D	72F	144F
50D	36F	48F	72F	96F

Wrapping Fibers

The composition of wrapping fibers contains polyester and cotton in the ratio of 63 to 35. Second-grade Tibetan lint cotton and polyester fibers with 1.56 tex*38 mm are selected. The qualities of the semi-product of yarn include a yarn unevenness rate of 18.9%, and a weight unevenness of 0.97%
Under the conditions that the yarn spacing, tex count of wrapping fibers at break draft and dimensions of yarn are determined, the function of core-spun yarns is primarily dependent on number of twist, tension of core yarn and so on. The core-spun yarn tested is 20 S+50 D.
Applicable Yarn Count
Dimension of Core-Spun Yarns


	yarn count	Core yarn

	20S	50D
	32S	50D
	40S	30D
	50S	20D

The core spun yarns 10, 20 can be formed into a woven fabric by a weaving machine. The woven fabric may have a weaving configuration such as Poplin weave, Poplin Rip stop weave (as shown in FIG. 3), left hand Twill 2:1 weave, left hand Twill 2:2 weave, left hand Twill 3:1 weave, right hand Twill 2:1 weave, right hand Twill 2:2 weave, right hand Twill 3:1 weave (as shown in FIG. 4), left hand Sateen 4:1 weave, right hand Sateen 4:1 weave, Canvas 1:1 weave, Canvas 2:2 weave, Oxford 2:2 double ply weave, Cavalry weave, Dobby weave, Jacquard weave, Corduroy weave or Flannel weave.
The core spun yarns 10, 20 can also be formed into a knitted fabric by a knitting machine. A weft knit fabric may have a weft knit configuration such as Jersey, Rib 1×1, Rib 2×1, Rib 2×2, Rib 3×3, Single Pique, Double Pique, Fleece, French Terry, Interlock, Feeder Stripe, Engineering Stripe, Dobby or Jacquard. A warp knit fabric may have a warp knit configuration such as Tricot or Rachel.
The woven and knitted fabric may include 100% core spun yarns 10, 20. The woven and knitted fabric may also include regular yarns. The proportion of core spun yarn to regular yarn may have different ratios. For example, the ratio of core spun yarn to regular yarn may be one core spun yarn to one or more regular yarns. The regular yarns can be in the form of non-core yarns or any other suitable spun yarns of simply construction. The mixing of regular yarns with core spun yarns 10, 20 of the present application can reduce the manufacturing cost of the woven and knitted fabric formed therefrom. The ratio of one core spun yarn 31, 41 to one regular yarn 32, 42 in woven fabrics is illustrated in FIGS. 3 and 4.
It is contemplated that the woven and knitted fabric of the present application can be formed into various articles of apparel such as T shirts, polo shirts, knit shirts, knit shorts, knit pants, knit jackets, woven shirts, woven pants, woven jackets, denim jeans, denim shirts, denim jackets, chambray shirts, yarn dyed shirts, yarn dyed shorts, yarn dyed pants, bed sheets and pillow cases.
In the drawings and the above description, there has been set forth an embodiment of the patent application. It is appreciated that the choices of core material, wrapping material, core spun spinning method, weaving/knitting method, core spun yarn to regular yarn ratio and apparel application are used in a generic and descriptive sense only and not for the purposes of limitation.

Example

In one exemplary embodiment, the fabric includes a core spun yarn wherein the core material is a polyester filament yarn of approximately 57 D overall in diameter, which is constituted by 48 strands of 1.2 D filaments. In this embodiment, the core spun yarn is produced by wrapping sheath fibers around the core material utilizing a ring spin core spun machine. The wrap material in this embodiment includes polyester staple fiber of 1.5 D with 38 mm staple length blended with cotton fiber in a ratio of 74.1% poly/25.9% cotton. In the present embodiment the weaving method is 3:1 Left Hand Twill, and the construction of the woven fabric is 128 yarns of Ne 20 s/l for warp yarn and 60 yarns of Ne 20 s/l for weft yarn. In the present embodiment, the ratio of core spun yarns to regular yarns is 1 core spun yarn interlaced with 1 regular non-core spun yarn of similar yarn count and blend. Thus, for every inch 64 core spun yarns and 64 regular spun yarns are employed as warp yarns, and 30 core spun yarns and 30 non-core spun yarns are employed as weft yarns. The fabric in the present embodiment is used to sew into a pair of pants. The fabric can be dyed and finished in a normal manner.
Demonstration of Improved Tear Strength Properties
To demonstrate the improved properties in tear strength of the fabric in the present embodiment as compared to a conventional polyester and cotton blended fabric, tests of the fabrics were conducted according to a test method entitled “ASTM D1424˜2009, Standard Test Method for Tearing Strength of Fabrics by Falling-Pendulum Type (Elmendorf) Apparatus”. In this test, a slit was precut at a center of a test specimen held between two clamps and the specimen was torn through a predetermined distance. The resistance to tearing was in part factored into the scale reading of the instrument and was computed from this reading and the pendulum capacity.
A fabric specimen of a core spun polyester and cotton fabric of the present embodiment was then tested. The construction of the fabrics and the results are shown in Table 1.

TABLE 1

T/C Twill 6.9 oz core spun fabric test
results - compared to Industry Standards:-

		Major Retailer	Test Report For
		Standard	Fabric In The Present
		Woven >7.0 Oz	Embodiment	Comparison

Tearing	Warp	4.0 lb	13.2 lb	3.3 times
	Weft	3.5 lb	9.1 lb	2.6 times
Tensile	Warp	60.0 lb	336.9 lb	5.6 times
	Weft	50.0 lb	144.0 lb	2.8 times

Demonstration of Improved Tensile Strength Properties
To demonstrate the improved properties in tensile strength of the fabric in the present embodiment as compared to a conventional polyester and cotton blended fabric, tests of the fabrics were conducted according to a test method entitled “ASTM D5034-2009, Breaking Strength and Elongation of Textile Fabrics (Grab Test)”. This test is described as follows:
1. A 100-mm (4.0-in.) wide specimen was held by clamps of a tensile testing machine and force was applied until the specimen breaks. Values of breaking force and elongation of the test specimen were obtained from machine scales, dials, autographic recording charts, or a computer interfaced with the testing machine.
2. This test method describes the procedures for carrying out fabric grab tensile tests using two types of specimens and three alternative types of testing machines. For reporting, the following identification system of specific specimen and machine combinations was used.
Type of Specimen:

G—Grab
MG−Modified grab

Type of Tensile Testing Machine:

E—Constant-rate-of-extension (CRE)
L—Constant-rate-of-load (CRL)
T—Constant-rate-of-traverse (CRT)

Possible combinations can be identified as follows:


	Type of Tester

	Constant-Rate-	Constant-Rate-	Constant-Rate-
Test Specimen	of-Extension	of-Load	of-Traverse

Grab	G-E	G-L	G-T
Modified Grab	MG-E	MG-L	MG-T

For example, test method D 5034, G-E refers to grab test carried out on a constant rate-of-extension tensile testing machine.
These tests show that the tensile strength of the polyester and cotton core spun fabric of the present embodiment is 2.8-5.6 times more than that of the conventional polyester and cotton blend woven fabric of equal or greater weight. Also, the tearing strength of the polyester and cotton core spun fabric of the present embodiment is 2.6-3.3 times more than that of the conventional polyester and cotton blend woven fabric of equal or greater weight.
Demonstration of Improved Wrinkle Resistance Properties
To demonstrate the improved properties in wrinkle resistance of the fabric in the present embodiment as compared to a conventional polyester and cotton blended fabric, tests of the fabrics were conducted according to a test method entitled “AATCC Test Method 124-2005: Appearance of Fabrics after Repeated Home Laundering”. In this test, flat fabric specimens were subjected to standard home laundering practices. A choice was provided for hand or machine washing, alternative machine wash cycles and temperatures, and alternative drying procedures. Evaluation was performed using a standard lighting and viewing area by rating the appearance of specimens in comparison with appropriate reference standards.
A fabric specimen of a core spun polyester and cotton fabric of the present embodiment was then tested. The construction of these fabrics and the results are shown in Table 2.

TABLE 2

T/C Twill 6.9 oz core spun fabric test
results - compared to Industry Standards:

	Test Report for
	Natural and
	Permanent
	Wrinkle
	Resistant
	fabric in
	the present
Major Retailer Standard	embodiment	Remark

Wrinkle Resistance	3.5 minimun	4.0	Natural and
(AATCC 124)	(With Resin)	(No Resin)	Permanent
			Wrinkle
			Resistant

The test shows that the wrinkle resistance rating of the present embodiment is rated at 4.0 without application of any resin.
Demonstration of Improved Abrasion Resistance Properties
To demonstrate the improved properties in abrasion resistance of the fabric in the present embodiment as compared to a conventional polyester and cotton blended fabric, tests of the fabrics were conducted according to a test method entitled ASTM D4966˜1998(2007), Option 1, “Abrasion Resistance of Textile Fabrics (Martindale Abrasion Test Method)”. This test is described as follows:
1. Abrasion resistance was measured by subjecting the specimen to rubbing motion in the form of a geometric figure, i.e., a straight line, which becomes a gradually widening ellipse, until it formed another straight line in the opposite direction and traced the same figure again under known conditions of pressure and abrasive action. Resistance to abrasion was evaluated by various means which are described as follow:
2. Evaluation
2.1 Option 1—The end point is reached on a woven fabric when two or more yarns have broken, or on a knitted fabric when a hole appears.
2.2 Option 2—The end point is reached when there is a change in shade or appearance that is sufficient to cause a customer to complain.
2.3 Changes of shade can arise from a variety of reasons, for example, loss of raised finish from a fabric or of boucle loops or effects from fancy yarns. Different types of yarn or fiber can cause pronounced changes in shade or appearance. In this case, the end point is assessed against the AATCC gray scale for color change.
2.4 The end point is reached when the shade change is assessed as the AATCC gray scale rating of 3 or lower.
2.5 Option 3—Determine the mass loss as the difference between the masses before and after abrasion. This loss may be expressed as a percentage of the mass before abrasion.
The fabric specimen of a core spun polyester and cotton fabric of the present embodiment was then tested. The construction of these fabrics and the results are shown in Table 3.

TABLE 3

T/C Twill 6.9 oz core spun fabric test
results - compared to Industry Standards:-

		Test Report for
	Major Retailer	fabric in the present
	Standard	embodiment	Comparison

Abrasion Resistance	2.550 cycles	over 70,000 cycle	>27 times
(ASTM D4966)	Martindale

This test shows that the abrasion resistance of the polyester and cotton core spun yarn fabric of the present embodiment is 27 times greater than that of the conventional polyester and cotton blend yarn woven fabric of equal or greater weight.
While the woven/knitted fabrics and core spun yarns disclosed in the present application have been shown and described with particular references to a number of preferred embodiments thereof, it should be noted that various other changes or modifications may be made without departing from the scope of the appending claims.

Claims

What is claimed is:

1. A core spun yarn comprising:

(a) a core draw textured yarn (DTY) consisting of a core material of polyethylene terephthalate (PET); and

(b) a wrapper wrapping around the core draw textured yarn and comprising a wrap material selected from the group consisting of 100% cotton staple fibers, polyester cotton blended staple fibers, 100% polyester staple fibers, 100% rayon staple fibers, 100% modal staple fibers, 100% fire retardant staple fibers, polyester rayon blended staple fibers and cotton rayon blended staple fibers and blends thereof.

2. The core spun yarn as claimed in claim 1, wherein a diameter of the core draw textured yarn is in a range of 20-50 D.

3. The core spun yarn as claimed in claim 2, wherein the diameter of the core draw textured yarn is 20 D, 30 D, 35 D, 40 D or 50 D.

4. A fabric comprising the core spun yarn as claimed in claim 2.

5. The fabric as claimed in claim 4, wherein F count of yarn of the fabric is in a range of 24-144.

6. The fabric as claimed in claim 4, wherein the F count of yarn of the fabric is 24, 36, 48, 72, 96 or 144.

7. The fabric as claimed in claim 6, further comprising a non-core yarn, wherein the fabric is formed with a mixture of the core spun yarns and the non-core yarns.

8. The fabric as claimed in claim 7, wherein a ratio of core spun yarns to non-core yarns is one core spun yarn to one or more non-core yarns.

9. The fabric as claimed in claim 7, wherein the mix of core spun yarns to non-core yarns is one core spun yarn interlaced with one non-core yarn of same yarn count and blend, and for every inch 64 core spun yarns and 64 non-core yarns are employed as warp yarns, 30 core spun yarns and 30 non-core yarns are employed as weft yarns.

10. The fabric as claimed in claim 5, comprising a weaving configuration selected from the group consisting of poplin weave, poplin rip stop weave, left hand twill 2:1 weave, left hand twill 2:2 weave, left hand twill 3:1 weave, right hand twill 2:1 weave, right hand twill 2:2 weave, right hand twill 3:1 weave, left hand sateen 4:1 weave, right hand sateen 4:1 weave, canvas 1:1 weave, canvas 2:2 weave, oxford 2:2 double ply weave, cavalry weave, dobby weave, jacquard weave, corduroy weave and flannel weave.

11. The fabric as claimed in claim 5, comprising a weft knit configuration selected from the group consisting of jersey, rib 1×1, rib 2×1, rib 2×2, rib 3×3, single pique, double pique, fleece, French terry, interlock, feeder stripe, engineering stripe, dobby and jacquard.

12. The fabric as claimed in claim 5, comprising a warp knit configuration selected from the group consisting of tricot and rachel.

13. The fabric as claimed in claim 5, wherein the fabric is produced by core spun yarns formed by a core sheath selected from the group consisting of ring spun core sheath, open-end core sheath and vortex core sheath.

14. The fabric as claimed in claim 5, wherein the core spun yarn is produced by wrapping the wrap material around the core material utilizing a ring spin core spun machine.

15. The fabric as claimed in claim 5, wherein the wrap material comprises polyester staple fiber of 1.5 D with 38 mm staple length blended with cotton fiber in a ratio of 74.1% poly/25.9% cotton.

16. The fabric as claimed in claim 5, comprising a weaving configuration of 3:1 left hand twill and a woven fabric construction of 128 yarns of Ne 20 s/l for warp yarn and 60 yarns of Ne 20 s/l for weft yarn.

17. The fabric as claimed in claim 5, wherein the fabric is sewn into a pair of pants, and the fabric is dyed and then finished.

18. An article of apparel made of the fabric of claim 5.

19. The article of apparel as claimed in claim 18, wherein the article of apparel is selected from the group consisting of T shirts, polo shirts, knit shirts, knit shorts, knit pants, knit jackets, woven shirts, woven pants, woven jackets, denim jeans, denim shirts, denim jackets, chambray shirts, yarn dyed shirts, yarn dyed shorts, yarn dyed pants, bed sheets and pillow cases.