CN114787433B

CN114787433B - Carpet made of self-bulking bicomponent fiber containing PTT

Info

Publication number: CN114787433B
Application number: CN202080085235.9A
Authority: CN
Inventors: D·G·马德莱内
Original assignee: Ruixun Co ltd
Current assignee: Ruixun Co ltd
Priority date: 2019-12-10
Filing date: 2020-12-08
Publication date: 2025-03-18
Anticipated expiration: 2040-12-08
Also published as: JP7730815B2; AU2020402757A1; BR112022007903A2; WO2021118985A1; TW202129105A; US20220290367A1; MX2022006779A; CA3152951A1; KR20220104699A; EP4073301A1; JP2023506733A; TWI868270B; CN114787433A

Abstract

本文公开了地毯，地毯的面纤维包含双组分纤维，双组分纤维包含聚(对苯二甲酸亚乙酯)均聚物或聚(对苯二甲酸亚乙酯)共聚物的一种组分以及聚(对苯二甲酸三亚甲基酯)聚合物或聚(对苯二甲酸三亚甲基酯)与聚(对苯二甲酸亚乙酯)均聚物或聚(对苯二甲酸亚乙酯)共聚物的共混物的第二组分，其中，双组分纤维由于差异收缩而为自膨化性的。还公开了一种用于制备纱线以生产地毯的改进的方法，地毯的面纤维包含自膨化性双组分纤维，双组分纤维包含聚(对苯二甲酸亚乙酯)均聚物或聚(对苯二甲酸亚乙酯)共聚物的一种组分以及聚(对苯二甲酸三亚甲基酯)或聚(对苯二甲酸三亚甲基酯)与聚(对苯二甲酸亚乙酯)均聚物或聚(对苯二甲酸亚乙酯)共聚物的共混物的第二组分。Disclosed herein is a carpet having a face fiber comprising bicomponent fibers comprising one component of a poly(ethylene terephthalate) homopolymer or a poly(ethylene terephthalate) copolymer and a second component of a poly(trimethylene terephthalate) polymer or a blend of poly(trimethylene terephthalate) and a poly(ethylene terephthalate) homopolymer or a poly(ethylene terephthalate) copolymer, wherein the bicomponent fibers are self-bulking due to differential shrinkage. Also disclosed is an improved process for preparing yarn for producing carpet, the face fibers of the carpet comprising self-bulking bicomponent fibers, the bicomponent fibers comprising one component of poly(ethylene terephthalate) homopolymer or poly(ethylene terephthalate) copolymer and a second component of poly(trimethylene terephthalate) or a blend of poly(trimethylene terephthalate) and poly(ethylene terephthalate) homopolymer or poly(ethylene terephthalate) copolymer.

Description

Carpet made from self-bulking PTT-containing bicomponent fibers

Technical Field

The present disclosure relates to carpets, and more particularly to carpets in which the face fibers comprise self-bulking poly (trimethylene terephthalate) (PTT) containing bicomponent fibers.

Background

In modern carpet manufacture, synthetic polymers (e.g., nylon, polyester, polypropylene) are typically used to produce fibers having a high level of bulking, which can be defined as an increase in the covering power or apparent volume of the fiber as compared to non-bulked or "flat" fibers. These bulked continuous fibers ("BCF") are typically monocomponent fibers produced on a spinning machine having a high temperature/high pressure jet and cooling cylinder specifically designed to mechanically impart bulk to the fiber. This process has several disadvantages. The high temperature, high pressure and turbulence of the fibers in the jet may damage the fiber filaments and adversely affect the physical properties of the fibers. Furthermore, the need to impart bulk by the jet/barrel process requires a reduction in fiber production speed compared to other spinning processes that do not require mechanical bulk, i.e., fully drawn yarn ("FDY") or partially oriented yarn ("POY") flat yarns.

One way to characterize textile fibers is by their amount of crimp. "crimp" refers to the waviness of a fiber and may be expressed as the number of crimps per unit length. The amount of crimp, also referred to herein as "crimp contraction," can be expressed by comparing the extended length of the fiber under load to the retracted length of the fiber under no load. The amount of crimp in the fibers may be naturally occurring (e.g., wool) or imparted to the synthetic fibers during manufacture to suit the desired end use. Crimping can be produced by twisting/untwisting POY on a false twist texturing machine using air and heat in a bulking jet (BCF) to produce a Draw Textured Yarn (DTY), or by differential shrinkage of side-by-side or eccentric sheath/core bicomponent fibers. A low level of crimp corresponds to a textile fiber having improved softness or bulk, and is desirable when opacity or coverage of the fabric is important. Alternatively, high levels of crimping result in fibers with significant levels of stretch and recovery and are valuable in apparel applications.

In carpet applications, lower levels of curl are desirable to impart high degree of bulking without significant stretch manifestations. Self-crimping high bulk yarns comprising bicomponent filaments for fabrics are described in U.S. patent No. 7,790,282. In apparel fabrics, side-by-side and eccentric sheath/core bicomponent fiber crimp characteristics are typically maximized to provide a high level of stretch in the fiber and the resulting fabric. U.S. Pat. No. 6,803,102 B1 to Talley et al, 10/12/2004, is an example of producing bicomponent fibers having an asymmetric fiber cross section, and is incorporated herein in its entirety.

U.S. patent No. 6,158,204 to taley et al, 12 months 2000 discloses a self-setting yarn made from bicomponent fibers that form a locking twist and form a bulking degree of spiral crimp. The use of such yarns in carpets and textiles is also disclosed. Various polymers are disclosed, such as poly (ethylene terephthalate) ("PET"), poly (butylene terephthalate) ("PBT"), polypropylene, nylon, and the like. However, the use of poly (trimethylene terephthalate) (PTT) is not disclosed.

U.S. Pat. Nos. 5,645,782 Howell et al, 6,109,015 Roark et al and 6,113,825 Chuah;WO 99/19557 Scott et al, H.Modlich, '' Experience with Polyesters Fibers in Tufted Articles of Heat-Set Yarns [ polyester fiber experience in use in heat-set yarn tufted articles ], CHEMIEFASERN/Textilind [ chemical fiber/textile industry ]41/93,786-94 (1991), and H.Chuah, '' Corterra Poly (TRIMETHYLENE TEREPHTHALATE) -New Polymeric Fiber for Carpets [ Corterra poly (trimethylene terephthalate) -novel carpet polymer fibers ] ', the Textile Institute [ society of textiles ] Tifcon'96 (1996) (available on http:// www.shellchemicals.com/corterra/0,1098,281,00. Html), all of which are incorporated herein by reference, describe carpets made with poly (trimethylene terephthalate) (PTT) monocomponent fibers (homofiber) instead of bicomponent fibers.

Disclosed herein is a carpet comprising a bicomponent fiber comprising one component of a poly (ethylene terephthalate) (PET) homopolymer or poly (ethylene terephthalate) copolymer (co-PET) and a second component of a poly (trimethylene terephthalate) (PTT) or a blend of PTT and PET homopolymer or PET copolymer (co-PET), wherein the bicomponent fiber is self-expanding due to differential shrinkage, in contrast to carpets in which the face fiber is made from mechanically expanded bulked continuous monocomponent filaments (homofilament).

Disclosure of Invention

In a first embodiment, disclosed herein is a carpet comprising a face fiber comprising a bicomponent fiber comprising one component of a poly (ethylene terephthalate) (PET) homopolymer or poly (ethylene terephthalate) copolymer (co-PET) and a second component of a poly (trimethylene terephthalate) (PTT) polymer or a blend of PTT and PET homopolymer or PET copolymer (co-PET), wherein the bicomponent fiber is self-bulked due to differential shrinkage, in contrast to carpets in which the face fiber is made from mechanically bulked continuous monocomponent filaments.

In a second embodiment, the bicomponent fibers may be in a side-by-side configuration or an eccentric sheath/core configuration.

In a third embodiment, the first component and the second component of the bicomponent fiber may be present in a weight ratio of 80:20 to 20:80.

In a fourth embodiment, the self-bulking bicomponent fibers disclosed herein have a post-heating crimp shrinkage of 30% or less as determined according to the crimp shrinkage methods disclosed herein.

In a fifth embodiment, an improved process for making yarn to produce carpet whose face fiber comprises self-bulking bicomponent fiber comprising one component of poly (ethylene terephthalate) (PET) homopolymer or poly (ethylene terephthalate) copolymer (co-PET) and a second component of poly (trimethylene terephthalate) (PTT) or a blend of PTT and PET homopolymer or PET copolymer (co-PET) is disclosed, the process comprising:

a) Extruding the two components on a spinning machine capable of producing two or more separate melt streams;

b) Combining the melt streams in a spinneret suitable for preparing bicomponent fibers;

c) Quenching the self-expanding bicomponent fiber produced in step (b) in air;

d) Stretching and heat setting the self-expanding bicomponent fiber, and

E) The self-expanding bicomponent fiber is wound by suitable means for subsequent processing into carpets,

Wherein the self-bulking bicomponent fibers eliminate the need for a mechanical bulking step.

In a sixth embodiment, the bicomponent fibers may be in a side-by-side configuration or an eccentric sheath-core configuration.

In a seventh embodiment, the first component and the second component of the bicomponent fiber may be arranged in a weight ratio of 80:20 to 20:80.

In an eighth embodiment, the self-bulking bicomponent fibers disclosed herein have a post-heating crimp shrinkage of 30% or less as determined according to the crimp shrinkage methods disclosed herein.

Detailed Description

All patents, patent applications, and publications cited herein are incorporated by reference in their entirety.

As used herein, the terms "embodiment" or "disclosure" are not intended to be limiting, but rather generally apply to any embodiment defined in the claims or described herein. These terms are used interchangeably herein.

In this disclosure, a number of terms and abbreviations are used. Unless otherwise specifically indicated, the following definitions apply.

The articles "a" and "an" preceding an element or component are intended to be non-limiting with respect to the number of instances (i.e., occurrences) of the element or component. Thus, the singular forms "a," "an," and "the" are to be construed to include the plural, unless the number clearly indicates otherwise.

The term "comprising" means the presence of stated features, integers, steps or components as referred to in the claims without excluding the presence or addition of one or more other features, integers, steps, components or groups thereof. The term "comprising" is intended to include embodiments encompassed by the terms "consisting essentially of. Similarly, the term "consisting essentially of the term" composition "is intended to include embodiments encompassed by the term" consisting of the term.

Where present, all ranges are inclusive and combinable. For example, when a range of "1 to 5" is recited, the recited range should be interpreted as including the ranges of "1 to 4", "1 to 3", "1 to 2 and 4 to 5", "1 to 3 and 5", and the like. As used herein in connection with a numerical value, the term "about" refers to a range of +/-0.5 of the numerical value, unless the term is specifically defined in the context. For example, the phrase "pH of about 6" means a pH of 5.5 to 6.5 unless the pH is specifically defined otherwise. Every maximum numerical limitation given throughout this specification is intended to include every lower numerical limitation, as if such lower numerical limitations were expressly written herein. Every minimum numerical limitation given throughout this specification will include every higher numerical limitation, as if such higher numerical limitations were expressly written herein. Every numerical range given throughout this specification will include every narrower numerical range that falls within such broader numerical range, as if such narrower numerical ranges were all expressly written herein.

As used herein, the term "bicomponent fiber" refers to a fiber comprising two different polymer components, which may be composed of different polymer types, the same polymer type but with different intrinsic viscosities, or a blend of two or more polymers, extruded from the same spinneret, wherein the two polymers are in the same filament. Bicomponent fibers may also be referred to as composite fibers, and these terms may be used interchangeably.

The term "BCF" refers to bulked or bulked continuous monocomponent filaments. It is essentially a long continuous fiber strand that is used to make carpets. The terms "bulks" and "bulking" are used interchangeably herein.

As used herein, the term "carpet" refers to a floor covering comprised of pile yarns or fibers and a backing system. They may be tufted or woven. As used herein, the term "carpet" includes whole house carpets, string carpets, rugs, and mats for vehicle and building entrances, such as those designed to capture underfoot soil.

The term "face" refers to the side of the carpet that contains tufted or woven yarns.

As used herein, the term "face fiber" refers to the fibrous content of the carpet, including the fibrous content that is visible to an observer. The face fibers are made primarily of yarns, and these yarns may be patterned in cut, loop, split and loop patterns or any number of patterns known to those skilled in the art.

The term "copolymer" refers to a polymer that is composed of a combination of more than one monomer. The copolymer may form the basis of some man-made fibers.

The term "crimp" refers to the waviness of a fiber expressed as the number of crimps per unit length. "crimping" is a process of imparting crimp to a filament yarn.

The term "crimp contraction" is a measure of the crimp of the fiber and refers to the contraction of the yarn in length from a fully extended state (i.e., wherein the filaments are substantially straight). This is due to the formation of curls in the individual filaments under specific curl exhibiting conditions. It is expressed as a percentage of the extended length. The crimp contraction may be measured before and/or after the fiber is treated (e.g., by heating) to partially or fully exhibit crimp, and typically the crimp contraction after heating is more interesting and provides more information because it includes the crimp exhibited by heating. The curl shrinkage values disclosed herein are post-heat curl shrinkage values (Cca), unless otherwise indicated.

The term "denier" is a weight per unit length measurement of any linear material.

The term "fiber" refers to a unit of matter that forms the basic element of fabrics and other textile structures, either natural or synthetic. Characterized by having a length at least 1000 times its diameter or width. Typically, textile fibers are units that can be spun into yarns or made into fabrics by a variety of methods including weaving, knitting, braiding, carpeting, and twisting. The fibers are characterized by their denier (grams weight per 9000 meters of fiber) and the number of filaments contained in the fiber.

"Filament" refers to a thread or a continuous bundle of fibers. There are two types of filaments, single filament (mono-filament) and multi-filament (multi-filament). Filaments are characterized by their denier per filament ("dpf").

The term "monocomponent filament" means that the filament is made from one polymer type.

"Staple" refers to a length of natural fibers or cut from filaments.

The term "intrinsic viscosity" ("IV") refers to the ratio of the specific viscosity of a solution of known concentration to the concentration of solute extrapolated to zero concentration.

The term "tufting" refers to a process of making a textile, such as a carpet, on a dedicated multi-needle machine. A "tuft" is a cluster of soft yarns that is drawn through the fabric and projects from the surface in the form of cut yarns or loops. The severed or unset loops form the face of a tufted or woven carpet.

The term "yarn" refers to a collection of individual filaments, either alone or in combination with another collection of filaments. The terms "fiber" and "yarn" are used interchangeably herein.

The term "quench" refers to rapid cooling in water, oil, or air to achieve certain physical or material properties.

The term "poly (ethylene terephthalate)" or PET means a polymer derived substantially solely from ethylene glycol and terephthalic acid (or equivalent such as dimethyl terephthalate), and is also referred to as a poly (ethylene terephthalate) homopolymer. As used herein, the term "poly (ethylene terephthalate) copolymer" or "co-PET" refers to a polymer that comprises repeat units derived from ethylene glycol and terephthalic acid (or equivalent) and that also contains at least one additional unit derived from an additional monomer, such as isophthalic acid (IPA) or Cyclohexanedimethanol (CHDM). The poly (ethylene terephthalate) copolymer can contain from about 1 mole% to about 30 mole% of additional monomer, such as from about 1 mole% to about 15 mole% of additional monomer.

The term "poly (butylene terephthalate)" or PBT means a polymer derived from substantially only 1, 4-butanediol and terephthalic acid, and is also referred to as a poly (butylene terephthalate) homopolymer. As used herein, the term "poly (butylene terephthalate) copolymer" refers to a polymer comprising repeat units derived from 1, 4-butanediol and terephthalic acid and also containing at least one additional unit derived from an additional monomer (e.g., a comonomer of the PTT copolymers disclosed herein).

The term "poly (trimethylene terephthalate)" or PTT refers to polyesters made by polymerizing 1, 3-propanediol with terephthalic acid. It is characterized by high elastic recovery (elastic recovery) and elasticity (resilience). PTT is known to provide stain resistance, static resistance, and improved staining. The term "poly (trimethylene terephthalate) homopolymer" means a polymer of substantially only 1, 3-propanediol and terephthalic acid (or equivalent). The term "poly (trimethylene terephthalate)" also includes PTT copolymers, meaning polymers that contain repeating units derived from 1, 3-propanediol and terephthalic acid (or equivalent) and that also contain at least one additional unit derived from additional monomers. Examples of the PTT copolymer include copolyesters prepared using 3 or more reactants each having two ester-forming groups. For example, a co-polymer (trimethylene terephthalate) may be used wherein the comonomer used to prepare the co-polymer is selected from the group consisting of linear, cyclic and branched aliphatic dicarboxylic acids having 4 to 12 carbon atoms (e.g., succinic acid, glutaric acid, adipic acid, dodecanedioic acid, and 1, 4-cyclohexanedicarboxylic acid), aromatic dicarboxylic acids other than terephthalic acid and having 8 to 12 carbon atoms (e.g., isophthalic acid and 2, 6-naphthalenedicarboxylic acid), linear, cyclic and branched aliphatic diols having 2 to 8 carbon atoms (other than 1, 3-propanediol, e.g., ethylene glycol, 1, 2-propanediol, 1, 4-butanediol, 3-methyl-1, 5-pentanediol, 2-dimethyl-1, 3-propanediol, 2-methyl-1, 3-propanediol, and 1, 4-cyclohexanediol), and aliphatic and aromatic ether diols having 4 to 10 carbon atoms (e.g., hydroquinone bis (2-hydroxyethyl) ether or polyethylene glycol having a molecular weight of less than about 460, including ethylene glycol). The comonomer is typically present in the copolyester at a level of from about 0.5 mole% to about 15 mole%, and may be present in an amount up to about 30 mole%.

The term "Triexta" refers to the generic name of the sub-class PTT of polyesters. The terms Triexta and PTT may be used interchangeably herein.

The poly (trimethylene terephthalate) typically has an intrinsic viscosity of about 0.5 deciliters per gram (d 1/g) or more, and typically about 2dl/g or less. The poly (trimethylene terephthalate) preferably has an intrinsic viscosity of about 0.7dl/g or more, more preferably 0.8dl/g or more, even more preferably 0.9dl/g or more, and typically the intrinsic viscosity is about 1.5dl/g or less, preferably 1.4dl/g or less, and currently available commercial products have an intrinsic viscosity of 1.2dl/g or less. Poly (trimethylene terephthalate) can be sold under the trademarkCommercially available from dupont company (e.i. du Pont DE Nemours and Company, wilmington, DE) of Wilmington, telprader.

Carpets made from poly (trimethylene terephthalate) monocomponent fibers and their manufacture, and the manufacture of these fibers and fibers are described in U.S. Pat. Nos. 5,645,782 Howell et al, 6,109,015 Roark et al, and 6,113,8235 Chuah, U.S. Pat. Nos. 6,740,276, 6,576,340, and 6,723,799, WO 99/19557 Scott et al, H.Modlich, ' ' Experience with Polyesters Fibers in Tufted Articles of Heat-Set Yarns [ experience of polyester fibers in heat-set yarn tufted articles ], CHEMIEFASERN/Textilind, [ chemical fiber/textile industry ]41/93,786-94 (1991), and H.Chuah, ' ' Corterra Poly (TRIMETHYLENE TEREPHTHALATE) -New Polymeric Fiberfor Carpets [ Corterra poly (trimethylene terephthalate) -novel carpet polymer fibers ] ' ' The Textile Institute [ society of textiles ] Tifcon '96 (1996), all of which are incorporated herein by reference. Staple fibers are mainly used to make household carpets. BCF yarns are used to make all types of carpets and are generally preferred for carpets.

Typically, PTT-containing bicomponent fibers are used to make fabrics and garments having durable stretch properties. In contrast, such stretch properties are not required in the manufacture of carpets. In contrast, fibers used to make carpets are typically mechanically bulked to provide a high level of bulking, such fibers are typically referred to as "BCF" fibers.

Disclosed herein is a carpet comprising a bicomponent fiber comprising one component of a poly (ethylene terephthalate) (PET) homopolymer or poly (ethylene terephthalate) copolymer (co-PET) and a second component of a poly (trimethylene terephthalate) (PTT) or a blend of PTT and PET homopolymer or PET copolymer (co-PET), wherein the bicomponent fiber is self-expanding due to differential shrinkage, in contrast to carpets in which the face fiber is made from mechanically expanded, bulked continuous monocomponent filaments.

Also disclosed is an improved process for making yarn to produce a carpet, the face fiber of which comprises self-bulking continuous fibers comprising one component of a poly (ethylene terephthalate) (PET) homopolymer or poly (ethylene terephthalate) copolymer (co-PET) and a second component of a poly (trimethylene terephthalate) (PTT) or a blend of PTT and PET homopolymer or PET copolymer (co-PET), the process comprising:

c) Quenching the self-expanding bicomponent fiber produced in step (b) in air;

d) Stretching and heat setting the self-expanding bicomponent fiber, and

E) The self-bulking bicomponent fiber is wound by suitable means for subsequent processing into carpets.

The bicomponent fibers described herein may be in a side-by-side ("S/S") or eccentric sheath-core ("S/C") configuration. Bicomponent fibers can be made in a variety of cross-sectional shapes, such as circular, triangular, trilobal, fan-shaped, or other shapes, by using spinneret plates of each shape-specific, for example, as disclosed in U.S. patent No.6,803,102, which is incorporated herein by reference in its entirety.

Typically, the fibers used in carpets are monocomponent fibers that are subjected to a mechanical bulking step in the manufacturing process. In contrast, the face fibers thereof described herein comprise self-bulking continuous fibers that are self-bulking due to differential shrinkage of carpets comprising bicomponent fibers comprising poly (trimethylene terephthalate).

As described above, one of the components of the self-expanding bicomponent fiber is PTT or a blend of PTT with PET or with co-PET. PTT can be very effective in providing crimp due to its unique shrink characteristics compared to other commercially available polyesters. The other component of the self-bulking bicomponent fiber is PET or co-PET and since its shrinkage is minimal compared to PTT, this combination of components allows for the greatest difference in shrinkage and thus allows for curl to develop. In contrast, poly (butylene terephthalate) (PBT) is less preferred as a component for use with PTT or PTT/PET blends to prepare self-bulking bicomponent fibers because PBT, PTT and PTT/PET blends will shrink significantly, resulting in lower differential shrinkage between the two components and thus lower crimp development of the resulting bicomponent fibers. For example, when the weight ratios of polymers in the side-by-side or eccentric sheath/core self-bulking bicomponent fibers are equal, bicomponent fibers comprising PTT and PET as the two components will provide a higher bulking degree than bicomponent fibers comprising PBT and PET as the two components or bicomponent fibers comprising two different PET as the two components each having a different Intrinsic Viscosity (IV).

Nylon polymers, including nylon 6 and nylon 66, may also be used as the first component of the self-bulking bicomponent fiber, however, nylon polymers generally do not have sufficient adhesion to the polyester as the second component and may split and crack when subjected to stress. Thus, bicomponent fibers comprising nylon and polyester may not be the best choice for carpet yarns.

The bicomponent PET or co-PET, and the PTT or blend of PTT and PET or coPET may be present in the self-expanding bicomponent fiber in a weight ratio of from 80:20 to 20:80. For example, the weight ratio of the first component to the second component may be 80:20, 75:25, 70:30, 65:35, 60:40, 55:45, 50:50, 45:55, 40:60, 35:65, 30:70, 25:75, 20:80, or any ratio within this range. In one embodiment, the weight ratio of the first component to the second component is about 50:50.

For use in carpets, the self-bulking bicomponent fibers have a curl shrinkage value after heating of 30% or less. The curl shrinkage after heating can be measured by the curl shrinkage method disclosed in the examples section below. There are several ways in which the two components of a bicomponent fiber can be adjusted to achieve a desired post-heat crimp contraction of 30% or less in the resulting bicomponent fiber. One option is to adjust the polymer Intrinsic Viscosity (IV) of each component relative to the other component. For example, if the IV difference between the two components of a bicomponent fiber is large, a high level of differential shrinkage between the two components occurs, resulting in high curl values and fiber stretch characteristics that are unsuitable for making carpets. In contrast, if the IV difference between the two components is too small, no substantial shrinkage difference occurs between the two components, resulting in little puffing.

Another way to produce bicomponent fibers with a preferred curl level is to vary the weight ratio of the two components. If the bicomponent fibers contain a significant proportion of PTT, the resulting fibers can have high crimp values and fiber draw. Conversely, very low amounts of PTT in the volume ratio may not provide sufficient overrun or curl shrinkage after heating to achieve the desired level.

A third way to produce bicomponent fibers with a preferred crimp level is to use a PET/PTT blend as one component and PET as the second component in a fixed ratio (e.g., 50/50 weight ratio of PTT to PET). It has been found that blending PET with PTT in one component can be used to improve the high shrinkage characteristics of PTT alone. When a bicomponent is made with one component comprising a blend of PTT and PET and the second component is PET, then fibers having equal weight ratios (e.g., 50/50w/w component 1 to component 2) can be prepared to provide the desired level of crimp, i.e., 30% or less crimp shrinkage after heating. In some spinneret designs, it may be desirable to prepare bicomponent fibers having nearly equal weight ratios of the two components, and blending PET with PTT is one way to achieve this result.

Alternatively, useful bicomponent fibers as disclosed herein may be prepared by varying the composition of the PTT/PET blend in one component of a bicomponent fiber in which the second component is PET or co-PET. This method can be used to prepare useful bicomponent fibers in which high levels of PET may be desired. In summary, varying the polymer type, IV, weight ratio, and blend composition is an all-technique by which self-expanding bicomponent fibers can be designed to achieve a target curl value that results in the desired degree of carpet expansion. Changing the relative speed of the rolls and/or winder during fiber production may also affect crimp shrinkage.

One benefit of the PTT in the self-bulking bicomponent fibers disclosed herein is that it provides a high level of shrinkage compared to PET. A relatively small amount of PTT may be used as one component of the self-expanding bicomponent fiber to produce a bicomponent fiber having the desired degree of expansion. However, too high a level of PTT content in the bicomponent fibers may result in a level of stretch that is too high to be useful for carpet yarns and would be more suitable for apparel applications.

Various additives may be added to one or both polymers. Such additives include, but are not limited to, lubricants, nucleating agents, antioxidants, ultraviolet stabilizers, pigments, dyes, antistatic agents, soil resistance agents, stain resistance agents, antibacterial agents, and flame retardants.

For use in carpets, the self-bulking bicomponent fibers disclosed herein may have a denier of from about 300 to about 1400 grams per denier. Useful denier/filaments may be from about 2 to about 20.

In one embodiment of a carpet whose face fibers comprise bicomponent fibers comprising one component of a PET homopolymer or coPET and a second component of a blend of PTT or PTT and PET homopolymer or coPET, wherein the bicomponent fibers are self-expanding due to differential shrinkage, the one component comprises a PTT having an intrinsic viscosity of about 0.9dL/g to about 1.25dL/g and the second component comprises a PET having an intrinsic viscosity of about 0.64dL/g, and the weight ratio of the two components is about 50/50.

In another embodiment, one component comprises PTT having an intrinsic viscosity of about 0.9dL/g to about 1.0dL/g and the second component comprises PET having an intrinsic viscosity of about 0.5dL/g, and the weight ratio of the two components is about 20/80 to about 30/70.

In another embodiment, one component comprises a 50/50 weight/weight blend of PTT and co-PET, where the PTT has an intrinsic viscosity of about 0.9dL/g to about 1.0dL/g and the co-PET has an intrinsic viscosity of about 0.75dL/g to about 0.85dL/g, and the second component comprises PET having an intrinsic viscosity of about 0.5dL/g, and the weight ratio of the two components is about 70/30 to about 30/70.

In another embodiment, one component comprises a blend of PTT and Co-PET, where PTT has an intrinsic viscosity of about 0.9dL/g to about 1.0dL/g and Co-PET has an intrinsic viscosity of about 0.75dL/g to about 0.85dL/g, and where the weight ratio of PTT and Co-PET in the blend is about 10/90 to about 90/10, and the second component comprises PET having an intrinsic viscosity of about 0.5dL/g, and the weight ratio of the two components is about 50/50.

The fibers may be made by delivering the polymer to a spinneret in a desired volume or weight ratio. While any conventional multicomponent spinning technique may be used, exemplary spinning apparatus and methods for preparing bicomponent fibers are described in U.S. Pat. No. 5,162,074 to Hills.

The self-bulking bicomponent fibers disclosed herein can be used with all other types of synthetic and natural fibers used to make carpets. Carpets can be made by mechanical or manual tufting, weaving, and hand knotting. Examples include 1) broad carpets (also known as full house carpets) in which tufted carpets are made in long continuous lengths of several meters wide for household and business applications, 2) modular carpets produced in squares of various sizes for ease of installation, 3) household rugs, and 4) mats for vehicle and building entrances designed to capture underfoot soil prior to entry into a building.

Any method known in the art for making carpets from fibers can be used to make the carpets described herein. Typically, the self-bulking bicomponent fibers disclosed herein can be used in the same carpet manufacturing process using other synthetic and natural fibers. The bicomponent fibers may be used on their own in carpet manufacture (i.e., as "single ply (singles)" yarns) or plied together with more identical bicomponent fibers or other fiber types (e.g., nylon, polypropylene, polyester) to increase denier. Optionally, the individual and plied fibers may be entangled with air jets prior to plying and may also be heat set by a machine specifically designed to heat set the physical properties of the individual and tufted yarns. An example of a heat setting machine suitable for this purpose is a heat setting machine consisting of(Mi Lusi, france (Muhouse)). Whether the bicomponent fibers are optionally air entangled, ply-twisted or heat-set, these fibers can be tufted into standard non-woven or woven backing sheets typical of the carpet industry. The face fiber loops in the tufted carpet may be severed to provide a loop-cut carpet. After tufting, an adhesive is often applied to the back of the carpet (i.e., the side opposite the face fibers) to hold the tufts in place. Additional backing layers may also be added to the back of the carpet. The adhesive layer may contain fillers or flame retardants depending on the particular carpet end use. The carpet may then be dyed by standard processes common to the carpet manufacturing industry, alternatively pigments may be added to the bicomponent and/or companion fibers during fiber extrusion to impart color to the finished fabric. In addition, the facing yarn may be treated with materials designed to impart fire resistance, antistatic properties, or stain and soil resistance. The finished carpet is often dried to remove water remaining in the dyeing process.

The above manufacturing process is a typical process for tufted carpets of wide width. Variations on this method known in the industry may be used in the production of rugs, string carpets and vehicular mats.

One feature of the bicomponent fibers disclosed herein is that the curl and bulking are exhibited by increasing the temperature of the fibers to at least 75 ℃ but below 200 ℃. During optional heat setting, dyeing and drying steps, the bicomponent fibers will be subjected to this temperature range during standard procedures for carpet production. Alternatively, the carpet may be subjected to a separate heating step to exhibit puffing, or the bicomponent fibers (single or ply) may be heat treated to exhibit puffing.

The facing fibers comprising the bicomponent fibers may have a circular or non-circular cross-section, such as a trilobal shape. It should have a curl shrinkage after heating of 30% or less.

An advantage of the carpets disclosed herein is that because the bicomponent fibers are self-bulking due to their differential shrinkage, mechanical bulking of the yarns used to make the carpets is not required. In contrast, carpet yarn made from bulked continuous monocomponent filaments will require mechanical bulking because it cannot undergo differential shrinkage. In other words, by using bicomponent fibers with differential shrinkage to make carpets, the step of mechanical bulking of continuous monocomponent filaments is eliminated.

Optionally, carpets whose face fibers comprise the self-bulking bicomponent fibers disclosed herein may further comprise at least one additional fiber. The at least one additional fiber may be plied with the self-bulking bicomponent fiber to increase denier (for example), or may be used as an additional carpet yarn when tufting a carpet. The at least one additional fiber may be selected from the group consisting of bulked continuous filaments (i.e., monocomponent filaments), synthetic staple fibers, and natural fibers. In one embodiment, the at least one additional fiber is a bulked continuous filament, and the bulked continuous filament comprises nylon, polypropylene, or polyester. In another embodiment, the at least one additional fiber is a synthetic staple fiber, and the synthetic staple fiber comprises nylon or polyester. In another embodiment, the at least one additional fiber is a natural fiber and the natural fiber comprises wool, silk, or cotton.

Non-limiting examples of embodiments disclosed herein include:

1. A carpet comprising a face fiber comprising a bicomponent fiber comprising one component of a poly (ethylene terephthalate) (PET) homopolymer or poly (ethylene terephthalate) copolymer (co-PET) and a second component of a poly (trimethylene terephthalate) (PTT) or a blend of poly (trimethylene terephthalate) (PTT) and a poly (ethylene terephthalate) (PET) homopolymer or poly (ethylene terephthalate) copolymer (co-PET), wherein the bicomponent fiber is self-expanding due to differential shrinkage, in contrast to a carpet in which the face fiber is made from mechanically expanded bulked continuous monocomponent filaments.

2. The carpet of embodiment 1, wherein the bicomponent fibers can be in a side-by-side configuration or an eccentric sheath-core configuration.

3. The carpet of examples 1 or 2, wherein the first component and the second component of the bicomponent fiber are present in a weight ratio of 80:20 to 20:80.

4. The carpet of examples 1, 2 or 3, wherein the bicomponent fiber has a post-heating crimp shrinkage of 30% or less as determined according to the crimp shrinkage method.

5. The carpet of embodiments 1, 2,3 or 4, wherein the face fiber further comprises at least one additional fiber selected from the group consisting of bulked continuous filaments, synthetic staple fibers, and natural fibers.

6. The carpet of embodiment 5, wherein the at least one additional fiber is a bulked continuous filament and the bulked continuous filament comprises nylon, polypropylene, or polyester.

7. The carpet of embodiment 5, wherein the at least one additional fiber is a synthetic staple fiber and the synthetic staple fiber comprises nylon or polyester.

8. The carpet of embodiment 5, wherein the at least one additional fiber is a natural fiber and the natural fiber comprises wool, silk, or cotton.

9. An improved process for making yarn to produce carpet whose face fiber comprises self-bulking bicomponent fiber comprising one component of poly (ethylene terephthalate) homopolymer or poly (ethylene terephthalate) copolymer and a second component of poly (trimethylene terephthalate) or a blend of poly (trimethylene terephthalate) and poly (ethylene terephthalate) homopolymer or poly (ethylene terephthalate) copolymer, the process comprising:

c) Quenching the self-expanding bicomponent fiber produced in step (b) in air;

d) Stretching and heat setting the self-expanding bicomponent fiber, and

10. The improved method of example 9, wherein the bicomponent fibers can be in a side-by-side configuration or an eccentric sheath-core configuration.

11. The improved process of embodiment 9 or 10 wherein the first component and the second component of the bicomponent fiber are present in a weight ratio of 80:20 to 20:80.

12. The improved process of examples 9, 10 or 11 wherein the bicomponent fiber has a post-heating crimp contraction of 30% or less as determined according to the crimp contraction method.

Examples

The present disclosure is further defined in the examples below. It should be understood that these examples, while illustrating certain embodiments, are given by way of example only. From the above discussion and the examples, one skilled in the art can ascertain the essential characteristics of this disclosure, and without departing from the spirit and scope thereof, can make various changes and modifications to adapt it to various uses and conditions.

As used herein, "comp.ex." means a comparative example; "Ex" means an example, "No." means a number, "%" means a percentage or percentage, "wt%" means a weight percentage, "IV" means an intrinsic viscosity, "dL/g" means deciliter/g, "g" means g, "mg" means mg, "C" means degrees Celsius, "° F" means degrees Fahrenheit, "temp" means a temperature, "min" means minutes, "h" means hours, "sec" means pounds, "kg" means kilograms, "mm" means millimeters, "gpl" means g/liter, "m/min" means meters/minute, "mol" means a mole "means kilograms," ppm "means parts per million," wt "means weight," dpf "means denier" means filaments, "gpd" or "means a temperature," min "means minutes," h "means an hour," sec "means seconds," lb "means pounds," kg "means a kilogram," kg "means a viscosity," tex "means a" millitex "mL" means a Newton "means a characteristic.

All materials were used as received unless otherwise indicated.

Measurement of after-heat crimp shrinkage (% CCa) -crimp shrinkage method

The curl shrinkage after heating (Cca) value was determined according to the methods described herein. The fibers of each example and comparative example were independently formed into skeins of about 5000+/-5 total denier (5550 dtex) using a skein under a tension of about 0.1gpd (0.09 dN/tex). The skein length is then halved by doubling it back to accommodate the inside of the oven used for heat setting. The folded skein was hung from a hook at its middle portion and conditioned at 70+/-1°f (21+/-1 ℃) and 65+/-2% relative humidity for at least 16 hours. The folded skein was then hung substantially vertically from the rack at its middle portion by hooks, and a weight of 1.5mg/den (1.35 mg/dtex) was hung from the bottom of the skein by two loops of the folded skein. The weighted skein was then heated in an oven at 250°f (121 ℃) for 5 minutes, after which the rack and skein were removed and allowed to cool for 5 minutes, and then conditioned at 70°f +/-1°f (21 +/-1 ℃) and 65% +/-2% relative humidity for at least 2 hours, with a weight of 1.5mg/den left on the skein for the remainder of the test. The length of the skein was measured to within 1mm and recorded as "Ca". Next, a 1000g weight was hung from the bottom of the skein to equilibrate and the length of the skein was measured within 1mm and recorded as "La". The after-heat curl shrinkage "CCa" value (%) was calculated according to the following formula:

%CCa=100x(La-Ca)/La

Determination of intrinsic viscosity

Intrinsic Viscosity (IV) was determined using Viscoteck Y C forced flow viscometer (malvern corporation of Houston, texas, USA, malvern Corporation). 0.15g of the sample was weighed into a 40mL glass bottle containing 30mL of solvent (phenol/1, 2-tetrachloroethane (60/40 weight percent)) and a stirring bar. The sample was then placed in a 100 ℃ pre-heated heating block (heat block), heated and stirred for 30 minutes, removed from the block and cooled for 30 to 45 minutes before being placed in the auto injector mount of the viscometer. The samples were then analyzed by ASTM method D5225-92(Standard Test Method for Measuring Solution Viscosity of Polymer With A Differential Viscometer[ using standard test methods for measuring the viscosity of polymer solutions with a differential viscometer).

Preparation of the Polymer

Two grades of PTT homopolymer pellets were obtained from DuPont company (E.I du Pont de Nemours and Company, wilmington, delaware USA) of Wilmington, del. One class has an IV of 1.02dL/g and the second class has an IV of 0.96 dL/g. PET homopolymer pellets were obtained from China Shanghai petrochemical Co., ltd (Sinopec Shanghai Petrochemical Company, ltd.Shanghai, PRC) and had an IV of 0.50 dl/g. From DuPontPET homopolymer pellets were obtained and had an IV of 0.64 dl/g. Co-PET copolymer pellets having an IV of 0.82dl/g (containing 1.9 mole% isophthalic acid) were obtained from Nanya plastics industries, inc. (NANYA PLASTICS Corporation, livingston New Jersey, USA) of Liwenston, N.J..

The polymer blend composition was made from a physical blend of 0.96IV PTT particles and 0.82IV PET copolymer particles ("salt and pepper" (S & P) blend) prior to extrusion. During spinning, these particle blends are intimately mixed during the extrusion process. Alternatively, in some examples, PTT and PET copolymer particles are compounded with a twin screw extruder, pelletized and used directly during spinning without the need to prepare salt and pepper blends.

In preparation for melt spinning, the pellets were dried in a vacuum oven at 120 ℃ under nitrogen for 15 hours under 25 inches mercury vacuum. The dried pellets were transferred directly to a nitrogen purged feed hopper of the spinning machine.

Preparation of fibers

The two components of the bicomponent fiber are melt spun using processes and equipment commonly used for spinning side-by-side and eccentric sheath/core bicomponent fibers, for example, as disclosed in U.S. patent No. 6,641,916B1, U.S. patent No. 6,803,102, and U.S. patent No. 7,615,173 B2, which are incorporated herein by reference.

In spinning the example bicomponent fibers, the polymer was melted in a pair of wiener He Pufu lydrel (Werner & Pfleiderer) co-rotating 28mm twin screw extruders having a capacity of 0.5 to 40 lbs/hr (0.23 to 18.1 kg/hr). One extruder (referred to herein as the East extruder) was used to melt the PET homopolymer (0.50 IV and 0.64 IV) pellets and a second extruder (referred to herein as the West extruder) was used to melt 1) the individual PTT pellets, 2) a salt and pepper ("S & P") blend of PTT pellets and co-PET co-pellets, or 3) compounded PTT/co-PET pellets. The temperatures of the West extruder, spinning block, and East extruder are listed in the examples. Each extruder feeds a spinning module containing a concave spinneret. The spinneret used was a post-coalescing, side-by-side bicomponent spinneret having thirty-four pairs of capillaries arranged in a circle with an internal angle of 30 degrees between each pair of capillaries, a capillary diameter of 0.64mm and a capillary length of 4.24mm.

The bicomponent filaments exiting the spinneret were cooled by cross-flow quench air at nominally 20 ℃ and 0.5mm/s face velocity. The filaments were then advanced to a double feed roll which was run at about 800 to 1200 meters per minute depending on the draw ratio. Between the spinneret and the feed roll, a finish applicator is used to lubricate the filaments Shu Shitu. To affect stretching, the feed rolls are typically heated to 70 ℃. The filament bundles are then accelerated to an annealing roll, which is run at a speed of about 3000 to 3600m/min, depending on the desired draw ratio, and the annealing roll temperature is typically 170 ℃. The annealed bicomponent fibers were then advanced to two sets of dual relax (letdown) rolls operating at room temperature before winding on a barag SW6 winding machine. The fiber has a snowman (oval) cross-sectional shape.

Example 1

Variation of PTT Intrinsic Viscosity (IV)

Example 1 shows the use of PTT particles having different IVs to produce bicomponent fibers having a desired value of crimp shrinkage after heating (CCa). The PTT particles used to prepare the fibers had an IV of 1.25dl/g (1 a) or 1.02dl/g (1 b). The IV of the PET-granulate is in both cases 0.64dl/g. The weight ratio of PTT to PET was 50/50 for each example. Example 1-a is a 115 denier 34 filament fiber. Example 1-b is a 75 denier 34 filament fiber.

TABLE 1 Process conditions and curl shrinkage for examples 1a and 1b

Example 2

Variation of PTT/PET weight ratio

Example 2 shows how changing the weight ratio of PTT and PET components in a bicomponent fiber changes the curl shrinkage after heating (CCa). The bicomponent fiber was 75 denier, 34 filaments. In table 2, comparative examples A, B and C exhibited high CCa levels, i.e., greater than 30%, and were more suitable for apparel products requiring stretch and recovery. Examples 2a, 2b and 2c illustrate process conditions that result in the production of high bulk bicomponent fibers having a crimp shrinkage after heating of 30% or less, which are suitable for use in the preparation of carpets. The winder speed was 3495m/min for comparative example A and 3500m/min for comparative examples B and C and examples 2a, 2B and 2C.

TABLE 2 Process conditions and curl shrinkage for comparative examples A, B and C and examples 2a, 2b, and 2C

Annotation:

* At 70 DEG C

* At room temperature

Example 3

Variation of weight ratio between two Components with fixed PTT/co-PET blend as one component

Table 3 shows how one component of the two-component is made with a 50/50 blend of PTT and co-PET, and how the second component is made from PET. In examples 3a to 3e, 50/50 weight percent of the "salt and pepper" blend of 0.96IV dl/g PTT particles and 0.82IV dl/g co-PET particles were mixed together until the particles were randomly dispersed. After drying, the pellet mixture was fed into a West extruder. The dried 0.50IV PET homopolymer pellets were fed into an East extruder. Bicomponent fibers were then prepared with a first component comprising a 50/50 weight blend of PTT/co-PET as described above and a second component being PET, wherein the weight ratio between the two components was varied. For example, example 3a was prepared at a 70/30 weight ratio between the first component (i.e., 50/50 PTT/co-PET blend) and the second component (i.e., PET). In the remaining examples in table 3, the polymer remained unchanged and only the weight ratio between the two components was changed. For all of these examples, the winder speed was 3500m/min.

TABLE 3 example 3 Process conditions and the resulting curl shrinkage

Example 4

Variation of PTT/co-PET blend ratio in one component with fixed weight ratio between the two components

Table 4 shows how one component of the two-component is made with a blend of PTT and co-PET, and how the second component is made from PET. The examples shown in Table 4, compared to Table 3, show the effect of varying the blend ratio of PTT and co-PET in the first component while maintaining a constant 50/50 weight ratio between the two components. In Table 4, examples 4a to 4D and examples 4f to 4g and comparative example D were prepared by varying the particle ratio in the "salt and pepper blend" ("S & P") of 0.96IV dl/g PTT and 0.82IV dl/g co-PET. The particles are mixed together until randomly dispersed. After drying, the pellet mixture was fed into a West extruder. The dried 0.50IV PET homopolymer pellets were fed into an East extruder. Bicomponent fibers were then prepared with a first component comprising the PTT/co-PET blend described above and a second component comprising PET, wherein the weight ratio between the two components was fixed at 50/50. For example, in example 4a, a two-part first part is made of PTT/co-PET in a 10/90 blend ratio and a two-part second part is made of PET. The weight ratio between the two components was 50/50. In example 4-e, PTT and co-PET pellets were pre-compounded in a twin screw extruder, quenched, pelletized and re-dried prior to use. This is in contrast to example 4d, where the components are made from salt and pepper blends. It should also be noted that comparative example D contained a higher value of the curl shrinkage after heating,% cca=43.1, which is more suitable for high stretch levels of clothing fabrics.

The winder speed was 3475m/min for example 4-a, 3500m/min for examples 4-b, 4-c, 4-D, 4-e, 4-f, 4-g and comparative example D.

TABLE 4 Process conditions and curl shrinkage for examples 4 a-4 g and comparative example D

Example 5

Carpet production Using self-bulking bicomponent fibers of example 2a

Carpets comprising self-bulking bicomponent fibers can be spun at 1200 denier to 120 filaments (10 dpf) using the polymers, polymer IV, and fiber weight ratios described in example 2a above. These bicomponent fibers will have a higher denier and filament count than example 2 a. The spinning speed (i.e., draw ratio) will be adjusted so that the resulting fiber has a curl shrinkage after heating of 30% or less. The bicomponent fibers so produced can be plied with a second bicomponent fiber of the same type on standard twisting equipment. After twisting, can pass throughThe fibers are processed by a sizing device that will fully develop the crimp of the bicomponent fibers and shape the twist in the plied yarns. The heat-set bicomponent yarn can then be tufted into a non-woven polypropylene backing on a standard carpet tufting machine along with other heat-set yarns of the same composition to give a tufted fabric consisting entirely of heat-set, ply-folded bicomponent yarns. The tufted fabric can then be processed on standard processing equipment used in the carpet industry to apply a latex formulation to the back of the carpet that locks the tufted face fibers into the woven carpet backing. A secondary backing will then be applied to protect the underside of the carpet. The raw (undried) carpet can be processed on standard continuous dyeing equipment and then dried in a continuous oven to remove moisture. The finished carpet is then rolled onto a large tube for field installation.

Example 6

Carpet production Using self-bulking bicomponent fibers of example 2a

Carpets comprising self-bulking bicomponent fibers can be spun at 1200 denier to 120 filaments (10 dpf) using the polymers, polymer IV, and fiber weight ratios described in example 2a above. The orifices are selected to produce side-by-side trilobal cross-sections, although any other cross-sectional shape useful for carpet manufacture may be selected. These bicomponent fibers will have a higher denier and filament count than example 2a, and a trilobal cross-sectional shape. The spinning speed (i.e., draw ratio) will be adjusted so that the resulting fiber has a curl shrinkage after heating of 30% or less. The bicomponent fibers so produced can be plied with a second bicomponent fiber of the same type on standard twisting equipment. After twisting, can pass throughThe fibers are processed by a heat setting device that will fully develop the crimp of the bicomponent fibers and set the twist in the plied yarns. The heat-set bicomponent yarn can then be tufted into a non-woven polypropylene backing on a standard carpet tufting machine along with other heat-set yarns of the same composition to give a tufted fabric consisting entirely of heat-set, ply-folded bicomponent yarns. The tufted fabric can then be processed on standard processing equipment used in the carpet industry to apply a latex formulation to the back of the carpet that locks the tufted face fibers into the woven carpet backing. A secondary backing will then be applied to protect the underside of the carpet. The raw (undried) carpet can be processed on standard continuous dyeing equipment and then dried in a continuous oven to remove moisture. The finished carpet is then rolled onto a large tube for field installation.

Claims

1. A carpet having a face fiber comprising bicomponent fibers comprising a first component of poly(trimethylene terephthalate) and a second component of poly(ethylene terephthalate) homopolymer, wherein the bicomponent fibers are self-bulking due to differential shrinkage, in contrast to carpets having a face fiber made from bulked continuous monocomponent filaments that have been mechanically bulked, wherein the bicomponent fibers have a post-heat crimp shrinkage as determined according to the crimp shrinkage method of 30% or less; the first component comprising poly(trimethylene terephthalate) having an intrinsic viscosity of 0.9 dL/g to 1.0 dL/g and the second component comprising poly(ethylene terephthalate) homopolymer having an intrinsic viscosity of 0.5 dL/g, and the weight ratio of the two components is 20:80 to 30:70.

2. A carpet having a face fiber comprising bicomponent fibers comprising a first component of poly(trimethylene terephthalate) and a second component of poly(ethylene terephthalate) homopolymer, wherein the bicomponent fibers are self-bulking due to differential shrinkage, in contrast to carpets having a face fiber made from bulked continuous monocomponent filaments that have been mechanically bulked, wherein the bicomponent fibers have a post-heating crimp shrinkage as determined according to the crimp shrinkage method of 30% or less; the first component comprising poly(trimethylene terephthalate) having an intrinsic viscosity of 0.9 dL/g to 1.25 dL/g and the second component comprising poly(ethylene terephthalate) homopolymer having an intrinsic viscosity of 0.64 dL/g, and the weight ratio of the two components is 50:50.

3. A carpet having a face fiber comprising bicomponent fibers comprising a first component of a blend of poly(trimethylene terephthalate) and poly(ethylene terephthalate) copolymers and a second component of poly(ethylene terephthalate) homopolymer, wherein the bicomponent fibers are self-bulking due to differential shrinkage, in contrast to carpets having a face fiber made from bulked continuous monocomponent filaments that have been mechanically bulked, wherein the bicomponent fibers have a post-heating crimp shrinkage as determined according to the crimp shrinkage method of 30% or less; wherein the first component The first component comprises a 50/50 weight/weight blend of poly(trimethylene terephthalate) and a poly(ethylene terephthalate) copolymer, wherein the poly(trimethylene terephthalate) has an intrinsic viscosity of 0.9 dL/g to 1.0 dL/g and the poly(ethylene terephthalate) copolymer has an intrinsic viscosity of 0.75 dL/g to 0.85 dL/g, and the second component comprises a poly(ethylene terephthalate) homopolymer having an intrinsic viscosity of 0.5 dL/g, and the weight ratio of the two components is 70:30 to 30:70.

4. A carpet having a face fiber comprising bicomponent fibers comprising a first component of a blend of poly(trimethylene terephthalate) and poly(ethylene terephthalate) copolymers and a second component of poly(ethylene terephthalate) homopolymer, wherein the bicomponent fibers are self-bulking due to differential shrinkage, in contrast to carpets having a face fiber made from bulked continuous monocomponent filaments that have been mechanically bulked, wherein the bicomponent fibers have a post-heat crimp shrinkage as determined according to the crimp shrinkage method of 30% or less; the first component comprising poly(trimethylene terephthalate) and poly(ethylene terephthalate) copolymers; A blend of poly(trimethylene terephthalate) copolymers, wherein the poly(trimethylene terephthalate) has an intrinsic viscosity of 0.9 dL/g to 1.0 dL/g, the poly(trimethylene terephthalate) copolymer has an intrinsic viscosity of 0.75 dL/g to 0.85 dL/g, and wherein the weight ratio of poly(trimethylene terephthalate) to poly(ethylene terephthalate) copolymer in the blend is 10/90 to 90/10, and the second component comprises a poly(ethylene terephthalate) homopolymer having an intrinsic viscosity of 0.5 dL/g, and the weight ratio of the two components is 50:50.

5. The carpet of claim 4, wherein the weight ratio of poly(trimethylene terephthalate) to poly(ethylene terephthalate) copolymer in the blend is from 10/90 to 70/30.

6. The carpet of any one of claims 1 to 4, wherein the bicomponent fibers are in a side-by-side configuration or an eccentric sheath-core configuration.

7. The carpet of any one of claims 1 to 4, wherein the face fibers further comprise at least one additional fiber selected from the group consisting of bulked continuous filaments, synthetic staple fibers, and natural fibers.

8. The carpet of claim 7, wherein the at least one additional fiber is a bulked continuous filament, and wherein the bulked continuous filament comprises nylon, polypropylene, or polyester.

9. The carpet of claim 7, wherein the at least one additional fiber is a synthetic staple fiber, and wherein the synthetic staple fiber comprises nylon or polyester.

10. The carpet of claim 7, wherein the at least one additional fiber is a natural fiber, and the natural fiber comprises wool, silk, or cotton.

11. An improved method for preparing yarn suitable for producing a carpet as claimed in any one of claims 1 to 10, the face fibers of the carpet comprising self-bulking bicomponent fibers,

The method comprises:

b) combining the melt streams in a spinneret suitable for producing bicomponent fibers;

c) quenching the self-bulking bicomponent fibers produced in step (b) in air;

d) stretching and heat setting the self-bulking bicomponent fiber; and

e) winding the self-bulking bicomponent fibers by suitable means for subsequent processing into carpet,

The self-bulking bicomponent fibers eliminate the need for a mechanical bulking step.