EP1412565A1 - Fibres de polyester modifie en polyethylene glycol - Google Patents

Fibres de polyester modifie en polyethylene glycol

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Publication number
EP1412565A1
EP1412565A1 EP02704168A EP02704168A EP1412565A1 EP 1412565 A1 EP1412565 A1 EP 1412565A1 EP 02704168 A EP02704168 A EP 02704168A EP 02704168 A EP02704168 A EP 02704168A EP 1412565 A1 EP1412565 A1 EP 1412565A1
Authority
EP
European Patent Office
Prior art keywords
copolyester
fibers
fiber
polyethylene glycol
copolyester fiber
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP02704168A
Other languages
German (de)
English (en)
Inventor
James Burch Branum
Keith James Carnes
Carl Steven Nichols
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Wellman Inc
Original Assignee
Wellman Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US09/761,446 external-priority patent/US6582817B2/en
Priority claimed from US09/827,441 external-priority patent/US6509091B2/en
Application filed by Wellman Inc filed Critical Wellman Inc
Publication of EP1412565A1 publication Critical patent/EP1412565A1/fr
Withdrawn legal-status Critical Current

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Definitions

  • the present invention relates to polyethylene glycol modified copolyester fibers that have exceptional moisture management characteristics and that can be formed into exceptionally comfortable fabrics.
  • Polyester filament is strong, yet lightweight, and has excellent elastic memory characteristics. Polyester fabric resists wrinkles and creases, retains its shape in garments, resists abrasions, dries quickly, and requires minimal care. Because it is synthetic, however, polyester is often considered to have an unacceptable appearance for garment purposes when initially formed as a filament. Accordingly, polyester filaments require texturing to produce acceptable characteristics of appearance, hand, and comfort in yarns and fabrics. Even then, polyester is often viewed unfavorably in garments. [0004] In pursuit of improved polyesters, various chemical modifications have been attempted to obtain desirable textile features. Unfortunately, some such treatments can produce unexpected or unwanted characteristics in the modified polyester.
  • polyethylene glycol enhances certain polyester properties, such as dye uptake, but diminishes other properties —especially those melt phase characteristics that are critical to filament spinning. Consequently, manufacturers have found that significant fractions of polyethylene glycol in copolyester can complicate — and even preclude — the commercial production of acceptable copolyester filaments.
  • modified polyesters must be compatible with commercial equipment with respect to melt-spinning, texturing, yarn spinning, fabric forming (e.g., weaving and knitting), and fabric finishing. This need for processing compatibility through conventional equipment has constrained the development of innovative polyester compositions.
  • polyester fibers are often blended with other kinds of fibers, both synthetic and natural. Perhaps most widely used in clothing are blended yarns and fabrics made of polyester and cotton. In general, blended fabrics of polyester and cotton are formed by spinning blended yarn from cotton fibers and polyester staple fibers., The blended yarns can then be woven or knitted into fabrics.
  • Cotton is formed almost entirely of pure cellulose. Cotton fibers are typically about one inch long, but can vary from about one half inch to more than two inches. Mature cotton fibers are characterized by their convolutions. Under a microscope, cotton appears as a twisted ribbon with thickened edges. Cotton is lightweight, absorbs moisture quickly and easily, and has a generally favorable texture (i.e., hand) when woven into fabrics. Cotton, however, lacks strength characteristics and elastic memory. Consequently, garments formed entirely of cotton require frequent laundering and pressing.
  • Blends of cotton and polyester fibers have found wide-ranging acceptance as they combine the desirable characteristics of each. Even so, there are continuing efforts to develop polyester filament, yarns, and fabrics that more closely resemble those of cotton, silk, rayon, or other natural fibers.
  • polyester microfibers which are characterized by extremely fine filaments that offer exceptionally good aesthetics and hand, while retaining the benefits of polyester. Polyester microfibers, however, have proved to be difficult to dye because of their high degree of molecular orientation and crystallinity.
  • 09/141,665 discloses a polyester composition that includes polyethylene terephthalate, polyethylene glycol in an amount sufficient to increase the wetting and wicking properties of a fiber made from the composition to a level substantially similar to the properties of cotton, but less than the amount that would reduce the favorable elastic memory properties of the polyester composition, and chain branching agent in an amount that raises the melt viscosity of the polyester composition to a level that permits filament manufacture under substantially normal spinning conditions. Including significant concentrations of branching agents to increase melt viscosity is sometimes undesirable, however, because branching agents promote cross-linking. This reduces filament strength, which can lead to processing failures.
  • the resulting PEG-modified polyester is then further polymerized in the solid phase until the copolyester is capable of achieving a melt viscosity sufficient to spin filaments (i.e., the solid copolyester would have that melt viscosity if it were melted without further solid state polymerization).
  • SSP solid state polymerization
  • this method reduces the need to add branching agents, such as pentaerythritol, to increase the melt-phase polymerization rate and thereby achieve an intrinsic viscosity that facilitates the spinning of filaments.
  • branching agents promote cross-linking, which can lead to relatively weaker textiles.
  • 09/484,822 describes a nonwoven fabric that is formed of polyethylene glycol modified copolyester fibers that include polyethylene terephthalate in an amount sufficient for the copolyester staple fibers to possess dimensional stability properties (e.g., shrinkage during home laundering) substantially similar to those of conventional, unmodified polyethylene terephthalate fibers, polyethylene glycol in an amount sufficient for the copolyester fibers to possess wicking characteristics that are superior to those of conventional, unmodified polyethylene terephthalate fibers, and chain branching agent in an amount less than about 0.0014 mole-equivalent branches per mole of standardized polymer.
  • polyethylene glycol modified copolyester fibers that include polyethylene terephthalate in an amount sufficient for the copolyester staple fibers to possess dimensional stability properties (e.g., shrinkage during home laundering) substantially similar to those of conventional, unmodified polyethylene terephthalate fibers, polyethylene glycol in an amount sufficient for the copolyester fiber
  • Nonwoven Fabrics Formed from Polyethylene Glycol Modified Polyester Fibers and Method for Making the Same the improved wicking that may be achieved in copolyester fibers by selectively incorporating polyethylene glycol is advantageous in nonwoven fabrics.
  • nonwoven personal care products employing this technology family possess exceptional moisture management characteristics and may be formed at significantly lower calendar bonding temperatures.
  • disposable diapers and other personal care products formed of nonwoven, synthetic fabrics are extremely popular.
  • disposable diapers made of such nonwoven fabrics have now essentially replaced cloth diapers in the marketplace. This is so not only because nonwoven fabrics offer an attractive cost structure, but also because nonwoven fabrics provide superior performance.
  • continued enhancements to nonwoven fabrics include weight reduction, aesthetic improvements, and, of particular relevance to diapers, increases in the number of uses an article can endure before requiring disposal.
  • nonwoven fabric having exceptional moisture management characteristics.
  • the nonwoven fabric is especially useful in absorbent, personal care products, such as wipes, absorbent undergarments (e.g., disposable diapers, training pants, and adult incontinence products), feminine hygiene products (e.g., sanitary napkins), and even durable goods that have the appearance, performance, and aesthetics of conventional textile goods.
  • Figure 1 describes the intrinsic viscosity of PEG-modified copolyester versus the weight fraction of polyethylene glycol when branching agent is employed in an amount of less than about 0.0014 mole-equivalent branches per mole of standardized polymer.
  • Figure 2 describes Multiple Insult Liquid Acquisition test results for a nonwoven fabric according to the present invention as compared to strength properties of a conventional nonwoven fabric.
  • Figures 3-4 describe strength properties of a nonwoven fabric according to the present invention as compared to strength properties of a conventional nonwoven fabric.
  • Figures 5-6 describe strength properties of a polyester/rayon blended nonwoven fabric according to the present invention.
  • Figure 7 describes Demand Wettability test results for a nonwoven fabric according to the present invention as compared to strength properties of a conventional nonwoven fabric.
  • Figure 8 describes an effective model for batch dyeing the copolyester fibers produced according to the present invention.
  • Figure 9 describes the effect of temperature on uptake of low-energy, medium-energy, and high-energy dyes at a pH of about 5.
  • Figure 10 describes the effect of pH upon low-energy, medium-energy, and high-energy disperse dyeing at 99°C (210°F).
  • Figure 11 describes the wicking properties of fabrics formed from copolyester fibers produced according to the invention as compared to the wicking properties of fabrics formed from conventional, unmodified polyethylene terephthalate fibers.
  • Figure 12 describes the drying properties of fabrics formed from copolyester fibers produced according to the present invention as compared to the drying properties of fabrics formed from conventional, unmodified polyethylene terephthalate fibers.
  • Figure 13 describes the flame-retardancy properties of fabrics formed from copolyester fibers produced according to the invention as compared to the flame-retardancy properties of fabrics formed from conventional, unmodified polyethylene terephthalate fibers.
  • Figure 14 describes the static-dissipation properties of fabrics formed from copolyester fibers produced according to the invention as compared to the static- dissipation properties of fabrics formed from conventional, unmodified polyethylene terephthalate fibers.
  • Figure 15 describes the abrasion resistance properties of fabrics formed from copolyester fibers produced according to the invention as compared to the abrasion resistance properties of fabrics formed from conventional, unmodified polyethylene terephthalate fibers.
  • Figure 16 describes the strength properties of fabrics woven from copolyester fibers produced according to the present invention as compared to the strength properties of fabrics woven from conventional, unmodified polyethylene terephthalate fibers.
  • Figure 17 describes the improved properties of fabrics formed from copolyester fibers produced according to the invention as compared to the properties of fabrics formed from conventional, unmodified polyethylene terephthalate fibers.
  • the present invention is a polyethylene glycol modified copolyester fiber that has exceptional moisture management characteristics and that can be formed into exceptionally comfortable fabrics.
  • the copolyester fiber includes polyethylene terephthalate in an amount sufficient for the copolyester fiber to possess dimensional stability properties substantially similar to those of conventional, unmodified polyethylene terephthalate fibers, polyethylene glycol having an average molecular weight of less than about 5000 g/mol in an amount sufficient for the copolyester fiber to possess wicking properties that are superior to those of conventional, unmodified polyethylene terephthalate fibers (i.e., between about 4 and 20 weight percent), and chain branching agent, if present, in an amount less than about 0.0014 mole-equivalent branches per mole of standardized polymer.
  • the copolyester fiber which has an intrinsic viscosity of at least about 0.67 dl/g, comprises polymer chains formed from structural units consisting essentially of diol monomers, non-substituted diacid monomers, and branching agent.
  • the non-substituted diacid monomers are aromatic non-substituted diacid monomers.
  • the invention is a polyethylene glycol modified copolyester composition that is particularly suitable for fibers.
  • the copolyester composition includes polyethylene terephthalate, preferably in amount sufficient for a fiber made from the copolyester composition to possess dimensional stability properties substantially similar to those of conventional, unmodified polyethylene terephthalate fibers.
  • the copolyester composition also includes polyethylene glycol having an average molecular weight of less than about 5000 g/mol and is present in an amount between about 4 and 20 weight percent.
  • the weight fraction of polyethylene glycol in the copolyester composition and the intrinsic viscosity of the copolyester composition are defined by the shaded region of Figure 1.
  • the copolyester composition also includes chain branching agent that comprises an ethoxylate and that will copolymerize with polyethylene terephthalate.
  • the chain branching agent is present in the copolyester composition in an amount less than about 0.0014 mole- equivalent branches per mole of standardized polymer, the standardized polymer being unmodified polyethylene terephthalate.
  • the copolyester composition comprises polymer chains formed from structural units consisting essentially of diol monomers, non-substituted diacid monomers, and branching agents. Most preferably, the non-substituted diacid monomers are aromatic non-substituted diacid monomers.
  • the invention relates to methods of preparing polyethylene glycol modified copolyester fibers that provide outstanding moisture management characteristics and that can be formed into exceptionally comfortable fabrics.
  • One such method includes copolymerizing polyethylene glycol and chain branching agent into polyethylene terephthalate in the melt phase to form a copolyester composition that comprises polymer chains formed from structural units consisting essentially of diol monomers, non-substituted diacid monomers, and chain branching agent, and that has an intrinsic viscosity of at least about 0.67 dl/g.
  • the copolyester composition has a zero-shear melt viscosity of between about 2000 and 3500 when heated to 260°C. (This melt viscosity facilitates the spinning of filaments.)
  • the method further includes spinning the copolyester composition into a filament.
  • Another such method includes copolymerizing polyethylene glycol and, optionally, chain branching agent into polyethylene terephthalate in the melt phase to form a copolyester composition, usually having an intrinsic viscosity of less than about 0.65 dl/g, and thereafter polymerizing the copolyester composition in the solid phase until the copolyester composition is capable of achieving a zero-shear melt viscosity of at least 2000 poise, preferably between about 2000 and 3500 poise, when heated to 260°C.
  • the method further includes spinning the copolyester composition into a filament.
  • the polyethylene terephthalate is typically present in the copolyester composition in an amount between about 80 and 96 weight percent, an amount sufficient for a fiber made from the copolyester composition to possess dimensional stability properties substantially similar to those of conventional, unmodified polyethylene terephthalate fibers.
  • the polyethylene glycol has an average molecular weight of less than about 5000 g/mol and is present in the copolyester composition in an amount between about 4 and 20 percent, an amount sufficient for a fiber made from the copolyester composition to possess wicking properties that are superior to those of conventional, unmodified polyethylene terephthalate fibers.
  • the chain branching agent is present in the copolyester composition in an amount less than about 0.0014 mole-equivalent branches per mole of standardized polymer, the standardized polymer being unmodified polyethylene terephthalate.
  • the chain branching agent is present in the copolyester composition in an amount between about 0.0003 and 0.0014 mole-equivalent branches per mole of standardized polymer.
  • copolymerizing polyethylene glycol and branching agent into polyethylene terephthalate is conventionally achieved by reacting ethylene glycol and either terephthalic acid or dimethyl terephthalate in the presence of polyethylene glycol and branching agent.
  • the copolymerization of polyethylene glycol and chain branching agent into polyethylene terephthalate yields a copolyester composition that includes polymer chains formed from stmctural units consisting essentially of diol monomers, non-substituted diacid monomers, and branching agent.
  • the copolymerization of polyethylene glycol and chain branching agent into polyethylene terephthalate yields a copolyester composition that includes polymer chains formed from stmctural units consisting essentially of diol monomers, aromatic non-substituted diacid monomers, and branching agent monomers, or, when branching agent is not present, polymer chains formed from stmctural units consisting essentially of diol monomers and aromatic non-substituted diacid monomers.
  • such copolyester compositions are preferably formed into copolyester fibers.
  • diol monomer refers to diols, such as ethylene glycol, propylene glycol, and butane diol, as well as ethers that possess terminal alcohols, such as diethylene glycol (DEG).
  • DEG diethylene glycol
  • polyethylene glycol is formed from such ethylene glycol monomers and is therefore embraced by the term “diol monomer.”
  • non-substituted diacid monomers refers to aromatic non-substituted diacid monomers and aliphatic non-substituted diacid monomers.
  • aromatic non-substituted diacid monomers refers to aromatic carboxylic diacids and diesters, especially terephthalic acid (TA) and its dialkyl ester, dimethyl terephthalate (DMT), whose functional groups are limited to those that facilitate polymer chain growth and that can be used to prepare modified polyethylene terephthalate.
  • TA terephthalic acid
  • DMT dimethyl terephthalate
  • aromatic non-substituted diacid monomers include single-ringed compounds, such as isophthalic acid and its dialkyl ester (i.e., dimethyl isophthalate), and polycyclic compounds, such as 2,6-naphthalene dicarboxylic acid or its dialkyl ester (i.e., dimethyl 2,6-naphthalene dicarboxylate)
  • non-substituted aliphatic diacid monomer refers to aliphatic carboxylic diacids and diesters, such as adipic acid and its dialkyl (e.g., dimethyl) ester.
  • various compounds may be included in copolymerization reactions to impart specific characteristics to the resulting copolymer.
  • Adipic acid for example, can improve the dyeing characteristics of polyester.
  • the present invention encompasses the copolymerization of polyethylene glycol and chain branching agent into polyethylene terephthalate to yield a copolyester composition that includes polymer chains formed from stmctural units consisting essentially of diol monomers, non-substituted diacid monomers (i.e., aromatic, aliphatic, or both), and branching agent.
  • branching agent refers to a multifunctional monomer that promotes the formation of side branches of linked monomer molecules along the main polymer chain. See Odian, Principles of Polymerization, pp. 18-20 (Second Edition 1981).
  • terminal ends of the copolyester chains may be structural units characterized by a lone, chain-propagating reactive site.
  • chain terminating groups are within the scope of both the phrase “consisting essentially of diol monomers, non-substituted diacid monomers, and branching agent," and the phrase “consisting essentially of diol monomers, aromatic non-substituted diacid monomers, and branching agent.”
  • mole-equivalent branches refers to the reactive sites available for chain branching on a molar basis (i.e., the number of reactive sites in excess of the two required to form a linear molecule).
  • pentaerythritol is a tefrafunctional branching agent, so it possesses two available chain branching reactive sites.
  • standardized polymer refers to the repeat unit of unmodified polyethylene terephthalate, which has a molecular weight of 192 g/mol.
  • polyethylene terephthalate polyethylene glycol
  • branching agent increasing the relative weight fraction of polyethylene glycol, which preferably has a molecular weight of less than 5000 g/mol, will decrease total moles.
  • the chain branching agent concentration of less than about 0.0014 mole-equivalent branches per mole of standardized polymer is based on the repeat unit of unmodified polyethylene terephthalate.
  • the weight fraction of branching agent should be calculated as if the polymer is made of only unmodified polyethylene terephthalate. Consequently, the weight fraction of polyethylene glycol (e.g., preferably between about 4 weight percent and 20 weight percent) and the molecular weight of the polyethylene glycol (e.g., preferably less than about 5000 g/mol) can be disregarded in calculating mole-equivalent branches per mole of standardized polymer.
  • an amount of pentaerythritol between about 0.0003 and
  • 0.0014 mole-equivalent branches per mole of the copolyester composition is equivalent to a weight fraction of between about 100 and 500 ppm when based on the standardized polymer of unmodified polyethylene terephthalate, whose repeat unit has a molecular weight of about 192 g/mol.
  • the mole-equivalent branches per mole of unmodified polyethylene terephthalate is 0.14 percent (i.e., 0.0014 mole-equivalent branches per mole of standardized polymer.)
  • BAMW molecular weight of the branching agent (g/mol)
  • SPMW 192 g/mol — molecular weight of the standardized polymer (i.e., unmodified polyethylene terephthalate)
  • an amount of pentaerythritol less than about 0.0014 mole- equivalent branches per mole of the copolyester composition would be equivalent to a weight fraction of less than about 450 ppm when based on polyethylene terephthalate that is modified by 20 weight percent polyethylene glycol having an average molecular weight of about 400 g/mol.
  • an amount of pentaerythritol less than about 0.0014 mole-equivalent branches per mole of the copolyester composition would be equivalent to a weight fraction of less than about 400 ppm when based on polyethylene terephthalate that is modified by 20 weight percent polyethylene glycol having an average molecular weight of about 5000 g/mol.
  • an amount of pentaerythritol less than about 0.0014 mole-equivalent branches per mole of standardized polymer is equivalent to a weight fraction of less than about 500 ppm regardless of the weight fraction or molecular weight of the polyethylene glycol.
  • the chain branching agent is may include a trifunctional or tetrafunctional alcohol or acid that will copolymerize with polyethylene terephthalate.
  • a trifunctional branching agent has one reactive site available for branching and a tetrafunctional branching agent has two reactive sites available for branching.
  • Acceptable chain branching agents include, but are not limited to, trimesic acid (C 6 H 3 (COOH) 3 ), pyromellitic acid (C 6 H 2 (COOH) 4 ), pyromellitic dianhydride, trimellitic acid, trimellitic anhydride, trimethylol propane (C 2 H 5 C(CH 2 OH) 3 ), ditrimethylol propane (C 2 H 5 C(CH 2 OH) 2 C 2 H 4 OC(CH 2 OH) 2 C 2 H 5 ), dipentaerythritol (CH 2 OHC(CH 2 OH) 2 C 2 H 4 OC(CH 2 OH) 2 CH 2 OH), and preferably pentaerythritol (C(CH 2 OH) ).
  • Polyethylene Glycol Modified Polyester Fibers and Method for Making the Same discusses using ethoxylated branching agents in PEG-modified copolyester. Accordingly, an aspect of this invention is the similar use of ethoxylated branching agents in PEG-modified copolyester, albeit at somewhat lower concentrations (i.e., less than 0.0014 mole-equivalent branches per mole of polymer).
  • Acceptable ethoxylated branching agents include, but are not limited to, ethoxylated glycerol (e.g., LUTROL HF-1, 530 g/mol; available from BASF); ethoxylated pentaerythritol (e.g., 3EO/4OH, 268 g/mol; 15 EO/4OH, 796 g/mol; each available from Aldrich Chemicals); and ethoxylated trimethylol propane (e.g., 2.5EO/OH, 437 g/mol; 20EO/3OH, 987 g/mol; each available from Aldrich Chemicals).
  • ethoxylated glycerol e.g., LUTROL HF-1, 530 g/mol; available from BASF
  • ethoxylated pentaerythritol e.g., 3EO/4OH, 268 g/mol; 15 EO/4OH, 796 g/mol; each available from Aldrich
  • Such ethoxylated branching agents can be used alone, or combined with non-ethoxylated branching agents.
  • the mole-equivalent branches per mole of unmodified polyethylene terephthalate is preferably less than 0.0014 mole- equivalent branches per mole of standardized polymer.
  • the present invention incorporates into polyester fibers, and hence yams and fabrics formed from such polyester fibers, the favorable properties of polyethylene glycol, such as its outstanding wicking properties, by employing a higher intrinsic viscosity. This compensates for the tendency of higher fractions of polyethylene glycol to lower the melt viscosity of the copolyester. Consequently, the present method of forming yams and fabrics from copolyester fibers need not employ significant amounts of branching agent. As will be understood by those of skill in the art, a low melt viscosity hinders the processing of copolyester through conventional spinning equipment.
  • copolyester fiber broadly refers to uncut filament (e.g., POY, flat-drawn yam, or textured yam) and cut fiber (e.g., staple fiber).
  • cut fiber e.g., staple fiber
  • copolyester filament may include fibers, such as staple, that are subsequently cut from spun filament, it is generally used to refer to an extmded fiber of indefinite length. The meaning of the terms “copolyester fiber” and “copolyester filament” will be easily understood by those of ordinary skill in the art based on the contextual use of these terms.
  • melt viscosity and "intrinsic viscosity” are used herein in their conventional sense. Melt viscosity represents the resistance of molten polymer to shear deformation or flow as measured at specified conditions. Melt viscosity is primarily a factor of intrinsic viscosity, shear, and temperature. As used herein, the term “melt viscosity” refers to "zero-shear melt viscosity” unless indicated otherwise.
  • the zero-shear melt viscosity at a particular temperature can be calculated by employing ASTM Test Method D-3835-93 A to determine melt viscosities at several shear rates between about 35 sec "1 and 4000 sec "1 , and thereafter extrapolating these melt viscosities to zero. In calculating zero-shear viscosity, it is recommended that several low shear rates, (e.g., less than 100 sec "1 ), be included to ensure that the extrapolation to zero is accurate. [0074] Intrinsic viscosity is the ratio of the specific viscosity of a polymer solution of known concentration to the concentration of solute, extrapolated to zero concentration.
  • Intrinsic viscosity is directly proportional to average polymer molecular weight. See, e.g., Dictionary of Fiber and Textile Technology, Hoechst Celanese Corporation (1990); Tortora & Merkel, Fairchild's Dictionary of Textiles (l l Edition 1996).
  • average molecular weight refers to number- average molecular weight, rather than weight-average molecular weight.
  • a 0.6-gram sample (+/- 0.005 g) of dried polymer sample is dissolved in about 50 ml (61.0 - 63.5 grams) of orthochlorophenol at a temperature of about 105°C. Fiber and yam samples are typically cut into small pieces, whereas chip samples are ground. After cooling to room temperature, the solution is placed in the viscometer and the relative viscosity is measured. As noted, intrinsic viscosity is calculated from relative viscosity.
  • the polyethylene glycol formulations include sufficient concentrations of antioxidants to prevent formaldehyde generation during spinning operations.
  • the polyethylene glycol used in the development of the present invention includes about 1.36 weight percent of Irganox 245, an antioxidant that is available from Ciba-Geigy. The inclusion of this or similar antioxidants will not adversely affect the products or methods herein described.
  • spinning refers to two different processes. In one sense, the term “spinning” refers to the production of synthetic polymer filaments from a polymer melt.
  • the term "spinning” refers to the process of twisting a plurality of individual fibers into yams.
  • the use of both of these terms is widespread and well understood in this art such that the particular use herein should be easily recognized by those of ordinary skill in the art.
  • copolyester characteristics can be tailored for specific applications by altering the polyethylene glycol content. This permits choice in designing fabrics made with copolyester or copolyester blends according to the present invention.
  • the invention establishes a technology family.
  • the weight fraction and the molecular weight of the polyethylene glycol can be adjusted to produce specific effects, such as wicking, drying, dye rates, stretch, and softness.
  • such modifications can improve the dye strike rate and reduce the dye usage.
  • higher polyethylene glycol fractions (e.g., greater than about 4 weight percent) result in softer fabrics that wick faster, dry quicker, and dye darker as compared to conventional polyesters.
  • the present copolyester shows as much as 30 percent more dye uptake of non-exhaustive polyester dye formulations as compared to conventional polyesters.
  • the polyethylene glycol is present in the copolyester composition in an amount between about 4 weight percent and 20 weight percent.
  • amounts of polyethylene glycol greater than about 20 weight percent are present, the resulting copolyester does not polymerize efficiently.
  • the copolyester composition is difficult to store and transport for it tends to crystallize, which causes undesirable sticking and clumping.
  • the polyethylene glycol fraction in the copolyester fibers is typically selected to enhance wickability.
  • polyethylene glycol amounts between about 10 weight percent and 20 weight percent are more preferred, and amounts between about 10 weight percent and 12 weight percent are most preferred.
  • polyethylene glycol may be used in amounts between about 15 weight percent and 20 weight percent. In other embodiments, polyethylene glycol is present at about 5 weight percent (e.g., amounts between 4 weight percent and 6 weight percent).
  • polyethylene glycol with an average molecular weight of less than about 5000 g/mol (e.g., between about 200 and 5000 g/mol)
  • the preferred average molecular weight for polyethylene glycol is between about 300 and 1000 g/mol, most preferably about 400 g/mol.
  • copolyester of the present invention that is modified between about 10 and 12 weight percent polyethylene glycol having a molecular weight of about 400 g/mol, unless indicated otherwise.
  • copolyester filaments are preferably spun at a temperature between about 260°C and 300°C. This temperature range comports with that employed in conventional spinning equipment using Dowtherm A vapor heat transfer media, which is available from Dow Chemical Co.
  • the copolyester need not be spun immediately after undergoing melt polymerization. Rather, the copolyester may be formed into chips after the step of copolymerizing polyethylene glycol and a chain branching agent into polyethylene terephthalate in the melt phase and before the step of spinning the copolyester composition into a filament. Where solid state polymerization is employed, the copolyester is formed into chips after the step of copolymerizing polyethylene glycol into polyethylene terephthalate in the melt phase and before the step of polymerizing the copolyester composition in the solid phase.
  • Figure 1 defines a desirable range of intrinsic viscosities of the copolyester composition as a function of the weight fraction of polyethylene glycol when chain branching agent is present in the copolyester composition in an amount less than 0.0014 mole-equivalent branches per mole of standardized.
  • the copolyester composition is preferably polymerized to an intrinsic viscosity of between about 0.67 and 0.78 dl/g.
  • the copolyester composition when the weight fraction of polyethylene glycol in the copolyester composition is between about 10 and 12 percent, the copolyester composition is preferably polymerized to an intrinsic viscosity of between about 0.73 and 0.88 dl/g. Finally, when the weight fraction of polyethylene glycol in the copolyester composition is about 15 percent, the copolyester composition is preferably polymerized to an intrinsic viscosity of between about 0.80 and 0.93 dl/g.
  • the invention is a nonwoven fabric having exceptional moisture management characteristics.
  • Such nonwoven fabrics are especially useful as personal hygiene products, such as disposable wipes or disposable undergarments, particularly diapers.
  • the nonwoven fabrics are formed from polyethylene glycol modified copolyester fibers, with or without one or more other kinds of fibers (e.g., rayon or polypropylene).
  • the nonwoven fabrics of the present invention have better wicking characteristics as compared to conventional nonwoven fabrics of a similar construction (i.e., a polyester-containing nonwoven fabric where the polyester fraction is defined by conventional, unmodified polyethylene terephthalate fibers rather than the present polyethylene glycol modified copolyester fibers).
  • nonwoven fabrics formed of 100-percent copolyester staple fibers of the present invention are superior to nonwoven fabrics formed of 100-percent conventional polyester staple fibers.
  • disposal wipes must be very absorbent.
  • rayon which is highly absorbent, is preferred. Nonetheless, polyester is often added to rayon blends to increase strength, improve processing performance, and reduce product costs.
  • polyester fibers in disposable wipes can inhibit absorbency.
  • the superior wicking of the copolyester fibers according to the present invention will improve the overall absorption rate in 50/50 polyester/rayon blended nonwoven fabrics. This is significant in disposable wipes, where absorbency is so desirable. Without being bound to a particular theory, it is believed that the PEG-modified copolyester fibers facilitate the movement of moisture to the rayon fibers.
  • the nonwoven fabric of the present invention is further characterized by an improved ability to retain its inherent wicking properties even after several liquid insults, as compared to a nonwoven fabric formed of an equivalent fraction of conventional, unmodified polyethylene terephthalate fibers.
  • the Multiple Liquid Insult Acquisition Test includes sequentially applying 50 ml dosages of a 0.9 percent saline solution to a horizontal sample, and observing each dosage for 12 seconds. Each nonwoven sample is placed over an industry-standard, super-absorbent core having a basis weight of about 600 grams per square meter. The super-absorbent core essentially provides infinite absorption within the constraints of the Multiple Liquid Insult Acquisition Test.
  • FIG. 1 depicts the amount of liquid overflowing versus time, indicating the amount of liquid that did not successfully make it through to the core. As will be understood by those familiar with diaper technology, low overflow with delayed onset of overflow is desirable.
  • the modified product shows appreciably less overflow of liquid when insulted by saline solutions.
  • the modified product shows considerably less liquid overflow and hence appreciably better performance than does the nonwoven formed from conventional polyester staple fibers.
  • a finish may be applied to the nonwoven fabric to complement its inherent wickability. This is a conventional technique to enhance fabric performance, but generally results in nonpermanent enhancement of wicking.
  • the nonwoven fabrics may be formed from any conventional technique, calendar bonding, hydroentangling, needlepunching, through-air-bonding, stitch-bonding, melt spun-bonding, and melt blowing are especially preferred.
  • the formation of copolyester fibers into a nonwoven fabric includes calendar bonding the copolyester fibers at a temperature of less than about 210°C. Although this is at least about 30°C below conventional calendar bonding temperatures, fabric strength is maintained.
  • melt spun-bonding is a continuous process whereby polymer is fed into an extruder and forced through a spinneret to form continuous filaments. The cooled filaments are formed into a continuous web on a conveyor belt.
  • melt blowing is a process in which molten polymer is extmded through a spinneret to form strands, which are stretched and broken by high velocity air or steam and then deposited on a conveyor in a web of fine fibers. See Tortora and Merkel, Fairchild's Dictionary of Textiles, (Seventh Edition 1996).
  • Figures 5 and 6 indicate that blended nonwovens according to the present invention are significantly stronger than conventional blended nonwovens, which are not commercially viable in calendar-bonded rayon blends without a binder fiber because of low strength.
  • binder fiber is generally expensive and, aside from fabric strength, enhances no meaningful fabric property.
  • the greater strength and elongation of the blended nonwoven that was formed from rayon fibers and 10-percent PEG-modified copolyester staple fibers indicates its commercial viability without employing a binder fiber.
  • the nonwoven fabric is a blended nonwoven fabric including at least one additional kind of fiber.
  • the copolyester staple fibers may be blended with cotton fibers, rayon fibers, polypropylene fibers, acetate fibers, nylon fibers, spandex fibers, biconstituent fibers, or even conventional polyester fibers.
  • the nonwoven fabric includes at least cellulosic fibers (e.g., rayon or cotton) in addition to the copolyester staple fibers.
  • the copolyester/ cellulosic blends preferably include between about 5 percent and 95 weight percent cellulosic fibers with the remainder comprising the copolyester fibers. Most preferably, the blend includes between about 30 weight percent and 70 weight percent cellulosic fibers with the remainder comprising the copolyester fibers.
  • nonwoven fabrics having exceptional moisture management properties may be formed from cellulosic fibers, which are present in the nonwoven fabric in an amount sufficient to provide excellent absorbency, and copolyester fibers, which are present in the nonwoven fabric in an amount sufficient to provide excellent wickability.
  • a 50/50 blend of rayon and copolyester has been found to provide excellent properties for wipes and other absorbent articles.
  • Figure 7 compares the absorbency rate of a blended modified nonwoven sample, which was formed from rayon fibers and copolyester staple fibers having about ten weight percent polyethylene glycol, with the absorbency rate of a conventional blended nonwoven sample fabric that was formed from rayon fibers and polyester staple fibers having no polyethylene glycol.
  • the nonwoven according to the present invention offers significantly increased absorbency as compared to the conventional nonwoven.
  • the enhanced wicking characteristics of the present copolyester fibers facilitate the movement of moisture to the highly absorbent rayon. This enables the fabric surface to absorb more liquid.
  • a nonwoven fabric including PEG-modified copolyester fibers and other fibers having low-melt temperatures can be formed by calendar bonding copolyester fibers and low-melt fibers at temperatures well below conventional calendar bonding temperatures.
  • Such low-melt fibers preferably include polypropylene fibers, low-melt polyester fibers, or biconstituent fibers of the same, all of which can be calendar bonded at a temperature of less than about 170°C.
  • the copolyester nonwoven fabric further includes biconstituent fibers, such as a polyester core surrounded by a sheath of polypropylene or low-melt polyester.
  • the invention is a copolyester fiber having improved dyeability.
  • the inclusion of PEG-modified copolyester fibers in a yam or fabric according to the present invention improves dyeing characteristics as compared to a yarn or fabric formed of an equivalent fraction of conventional, unmodified polyethylene terephthalate fibers.
  • the polyethylene glycol reduces melt temperature (T m ) and glass transition temperature (T g ).
  • T m melt temperature
  • T g glass transition temperature
  • the present invention facilitates dyeing the copolyester fibers at a temperature of less than about 116°C (240°F). Above 116°C (240°F), fastness may somewhat decrease using certain dyes at high concentrations.
  • the method includes dyeing the copolyester fibers at a temperature of less than about 110°C (230°F). In yet another preferred embodiment, the method includes dyeing the copolyester fibers at a temperature of less than about 104°C (220°F). In fact, the copolyester fibers can be dyed at or below the temperature defined by the boiling point of water at atmospheric pressure (i.e., 212°F or 100°C). It will be understood by those of ordinary skill in the art that dyeing the copolyester fibers includes dyeing yams and fabrics formed from such PEG-modified copolyester fibers, including blends with one or more other kinds of fiber.
  • the copolyester fibers can achieve excellent color depth even when dyed at 93 °C (200°F).
  • high-energy disperse dyes e.g., Color Index Disperse Blue 79
  • the copolyester fibers are most preferably dyed between about 93 °C (200°F) and 100°C (212°F).
  • low-energy disperse dyes e.g., Color Index Disperse Blue 56
  • the copolyester fibers are preferably dyed between about 82°C (180°F) and 93°C (200°F), and most preferably dyed between about 82°C (180°F) and 88°C (190°F).
  • high-energy dyes typically have better wash fastness and poorer light fastness as compared to low-energy dyes.
  • a particular advantage of the present invention is that the disclosed copolyester fibers may be dyed at atmospheric pressure without a carrier (i.e., a dye bath additive that promotes the dyeing of hydrophobic fibers), although leveling and dispersing agents are recommended.
  • a carrier i.e., a dye bath additive that promotes the dyeing of hydrophobic fibers
  • the present copolyester fibers do not require any pH modification.
  • the copolyester can be effectively disperse dyed in an alkaline dye bath having a pH as high as 10, limited only by the stability of the disperse dyes at such alkaline conditions and 99°C (210°F) rather than the properties of the present copolyester.
  • the copolyester fibers of the present invention have comparable hand to polyester microfibers (i.e., fibers ⁇ 1 dpf), yet demonstrate superior dyeing properties.
  • the yams and fabrics of the present invention can include PEG- modified copolyester fibers and cellulosic fibers (e.g., cotton fibers, rayon fibers, or acetate fibers) that can be dyed in one step.
  • PEG- modified copolyester fibers and cellulosic fibers e.g., cotton fibers, rayon fibers, or acetate fibers
  • cotton fibers e.g., reactive dyes
  • polyester is typically dyed at high temperatures (e.g. 129°C or 265°F) in acidic dye baths. Accordingly, dyeing blended cotton and polyester fabrics requires a two-step dyeing process.
  • Such blends are usually dyed in an alkaline pH using suitable cotton dyes to selectively dye the cotton fibers and are thereafter dyed in an acidic pH using disperse dyes to selectively dye the polyester fibers.
  • the present copolyester fibers do not require any pH adjustment and can be dyed effectively in an alkaline dye bath having a pH as high as 10. Consequently, blended fabrics that are made from PEG-modified copolyester fibers and cotton fibers or other cellulosic fibers can be dyed simultaneously in an alkaline dye bath that includes both reactive and disperse dyes.
  • dyeing such cellulosic/copolyester blends is carried out in a dye bath having a pH of about 10 or less and a temperature at or below the boiling point of water at atmospheric pressure (i.e., 100°C or 212°F).
  • the copolyester fibers formed according to the present invention also possess a high exhaustion rate, which translates to reduced dye costs and fewer environmental issues. In fact, dye uptake is maximized near the normal boiling point of water (i.e., 100°C or 212°F).
  • the dyeing of the copolyester fibers employs a relatively high ramp rate of about 2.8°C (5°F) per minute below 38°C (100°F), as the fibers absorb little dye at such temperatures. Above 38°C (100°F), however, the fibers do absorb dye and so the ramp rate should be reduced to about 1.1 °C (2°F) per minute to achieve level dyeing.
  • a holding period between about 5 and 10 minutes may be employed between about 49°C (120°F) and 88°C (190°F) to promote level dyeing.
  • An effective ramp technique for batch dyeing, especially for jet or beck dyeing, is illustrated as Figure 8. Minor adjustments to Figure 8 may be appropriate for package and beam dyeings. Because the copolyester fibers of the present invention begin to dye at 38°C (100°F), fabrics formed from the copolyester fibers should be home laundered in cold to warm water (i.e., less than 41°C or 105°F) to ensure that dyes from other fabrics do not stain the copolyester fabrics.
  • dyeing copolyester filaments broadly includes dyeing not only uncut filaments (e.g., partially oriented yarns or textured yams), but also cut filaments (e.g., staple fibers). Moreover, this concept further includes dyeing copolyester fibers that are formed into various yams or fabrics, either alone or in blends with one or more other kinds of fiber (e.g., cotton or spandex fibers).
  • PEG-modified copolyester was studied using Color Index Disperse Blue 56, 73, and 79. See Example 1 (below). These kinds of generic dyes, which are readily available, are representative low, medium, and high energy disperse dyes, respectively.
  • nonwoven fabrics will dye at least as well, if not better, than knit or woven fabrics. Accordingly, the following representative examples and data are also relevant to dyeing nonwoven fabrics.
  • the copolyester fabric used in the testing was a 2 x 2 twill fabric using a 150 denier 100 filament count textured continuous filament yam formed from copolyester fibers including between about 10 and 12 weight percent polyethylene glycol having a molecular weight of about 400 g/mol.
  • a comparison fabric made of conventional polyester was also employed. This fabric was plain woven, 38 x 58 greige count with crimped polyethylene terephthalate filament yam, and a fabric weight of 146 g/m 2 (4.3 oz/sq.yd).
  • the copolyester fabric was washed according to AATCC Test Method
  • Dyeing pH was adjusted by acetic acid and Na 2 CO 3 /NaHCO 3 buffer for the acidic and alkaline dyeing conditions, respectively. After dyeing, the fabrics were washed in a wash machine according to AATCC Test Method 124-1996, on normal cycle, at 41°C (105°F) for eight minutes, then tumble dried. After dyeing, the dye uptake was evaluated and compared by K S values at the wavelength with maximum absorbency. This describes shade depth and is directly proportional to dye concentration on the fiber, provided the shade depth is not too high. Wash fastness was examined according to AATCC Test Method 61- 2A(1996). Crock fastness was examined according to AATCC Test Method 8-1996.
  • Figure 10 depicts the pH effects upon disperse dyeing at 99°C (210°F).
  • Tables 1 and 2 (below), AATCC Method 61-2A (1996), commonly referred to as a 2A wash test, was used to evaluate wash fastness.
  • Tables 1 and 2 refer to a 1-5 visual rating system, wherein 5 is best and 1 is worst.
  • Table 1 (below) describes laundering colorfastness of copolyester fabric dyed with low-energy, medium-energy, and high-energy disperse dyes at different shade depths (i.e., 0.5%, 1.2%, and 3.0% dye owf). As might be expected by one having ordinary skill in the art, wash fastness decreased with increasing shade depth and the high-energy dyes had better wash fastness than low-energy dyes.
  • Table 2 (below) describes colorfastness of laundered fabrics dyed at different temperatures. In general, higher dyeing temperatures do not improve wash fastness.
  • the copolyester fiber produced according to the present invention had comparable wash fastness to that of conventional polyester fiber dyed at 129°C (265°F) (i.e., PET 265). Note, however, that the low-energy disperse dye resulted in poorer wash fastness as compared to the results using the high-energy disperse dye. Accordingly, lower-energy dyes might be better employed where good light fastness is required, but wash fastness is not required (e.g., automotive fabrics).
  • the copolyester fiber had better crock fastness than the conventional polyester fiber in most cases. The copolyester also had better wash fastness than the conventional polyester when using the high-energy dye Color Index Blue 79.
  • a distinct advantage of the present method is that it produces a copolyester fiber that, while possessing wetting, wicking, drying, soft hand, dye uptake, flame-retardancy, abrasion-resistance, stretch, and static-dissipation properties that are superior to those of conventional polyethylene terephthalate fibers, can be processed using conventional textile equipment.
  • the PET-modified copolyester can be spun into partially oriented yarns (POY).
  • POY is often comprised of from tens to hundreds of intermingled filaments (e.g., between 30 and 200) that are extmded from a spinneret at speeds typically between about 2000 and 4000 meters per minute.
  • the POY is then typically drawn to form a drawn yam, (e.g., by draw texturing, flat drawing, or warp drawing). Thereafter, the drawn yarn is formed into fabric, which is typically finished as well.
  • texturing POY can be effected in numerous ways, such as air jet texturing, gear crimping, and false-twist texturing.
  • copolyester fibers of the present invention may be textured according to various techniques, such as air jet, edge crimping, false-twist, gear crimping, knit-de-knit, and stuffer box methods.
  • Table 3 (below) discloses an exemplary set point and preferred set point ranges for texturing the copolyester POY using a contact false-twist texturing machine.
  • Table 4 discloses an exemplary set point and preferred set point ranges for texturing the copolyester POY using a non-contact false-twist texturing machine.
  • Table 5 discloses an exemplary set point and preferred set point ranges for draw-winding the copolyester POY using a draw-winding machine with heated godet rolls Table 5
  • Tables 3-5 "denier” depends on the POY denier and number of plies, and “secondary heat” applies to set yams. Moreover, “D/Y” is the ratio of disk speed to yarn speed, wherein the disk speed is the linear speed of a point on the circumference of the disk. It is re-emphasized that the disclosed settings (above) are exemplary rather than limiting, and that when the filament of the present invention is textured on another kind of machinery, those of ordinary skill in the art will be able to replicate the results described herein without undue experimentation.
  • flat drawn POY produced according to the invention results in yams having dyeing characteristics similar to those of cellulose acetate yams.
  • These copolyester yams are especially suitable for producing suit linings.
  • suit linings are conventionally jig dyed using low-energy dyes, which have poor fastness properties.
  • the yams and fabric formed according to the invention can be dyed on conventional jig dyeing equipment using high-energy dyes. Such yams and fabrics are machine washable, which is not possible with acetate products.
  • copolyester POY can be blended with at least one other kind of fiber (i.e., a fiber having a different chemical composition or having been differently processed) to form a blended yam.
  • the copolyester POY is typically either draw textured to form a draw-textured yam (DTY) or flat drawn to form a flat-drawn yarn (i.e., a hard yam) before blending.
  • the drawn copolyester yam is especially suitable for blending with cotton fibers, rayon fibers, polypropylene fibers, acetate fibers, nylon fibers, spandex fibers, and conventional polyester fibers.
  • the drawn copolyester yarn (e.g., DTY or hard yarn) can also be blended with a least one other kind of fiber to form blended fabric.
  • the drawn copolyester yarn is especially suitable for blending with cotton fibers, rayon fibers, polypropylene fibers, acetate fibers, nylon fibers, spandex fibers, conventional polyester fibers, and even copolyester staple fibers of the present invention.
  • the concept of forming a blended fabric from the drawn copolyester yarn and at least one other kind of fiber not only includes directly forming a fabric from the drawn copolyester yam and a second kind of fiber, but also includes first forming a blended yam before forming the blended fabric. In either case, however, the blended fabric is formed from a drawn copolyester yam and a second kind of fiber.
  • copolyester POY and nylon POY are formed into a blended yam. Thereafter, the blended yarn is textured. Moreover, because of dye selectivity, the resulting blended yam may be dyed with disperse dye, which preferentially dyes the copolyester component, and acid-based dye, which preferentially dyes the nylon component. In this way, a heather yam (or a two-colored yam) can be produced, which may then be formed into an attractive, heather fabric (or a two-colored fabric).
  • the invention further includes cutting the copolyester filaments into staple fibers.
  • the copolyester filaments can be spun from a single spinneret, typically at speeds of between about 500 and 2000 meters per minute.
  • the filaments, often from numerous spinneret positions, are combined into a tow.
  • the tow is often crimped before the filaments are cut into staple fibers.
  • the staple fibers can be formed into yam using any conventional spinning technique, such as ring spinning, open-end spinning, and air jet spinning. In this regard, open end and air jet spinning are becoming increasingly more preferred for polyester yams, as well as for blended yarns containing polyester.
  • the yams formed from the copolyester filaments of the invention in turn, can be woven or knitted into fabrics that have the advantageous characteristics referred to herein.
  • the staple fibers also can be formed directly into a nonwoven fabric.
  • the concept of forming staple fibers into fabric includes first forming a yam, (e.g., knitting and weaving), in addition to forming the staple fibers directly into fabric, (e.g., nonwoven fabric).
  • the method includes blending the staple copolyester fibers with at least a second kind of fiber, such as cotton fibers, rayon fibers, polypropylene fibers, acetate fibers, nylon fibers, spandex fibers, and conventional unmodified polyester fibers.
  • acetate fibers and spandex fibers are usually in filament form.
  • the staple fibers and the second kind of fiber can be spun into yam, and the yam formed into fabric using conventional techniques.
  • the staple fibers and the second kind of fiber can be formed directly into a nonwoven fabric.
  • the invention includes forming copolyester fibers from the copolyester composition as previously disclosed, and then blending the copolyester fibers with spandex fibers.
  • copolyester fiber broadly refers to uncut filament (e.g., POY, flat-drawn yam, or textured yam) and cut fiber (e.g., staple fiber).
  • the copolyester fibers and the spandex fibers can be blended into yam.
  • this comprises core spinning copolyester staple fibers around a core of spandex filaments.
  • the copolyester filaments preferably in the form of POY — are wrapped around spandex filaments.
  • the copolyester fibers and the spandex fibers may also be formed into fabric using conventional techniques.
  • the fabric may be formed, (e.g., woven or knitted), from a blended yam that is spun from the copolyester fibers and the spandex fibers.
  • the copolyester fibers and spandex fibers may be directly formed into a fabric, preferably a knit fabric.
  • the spandex is laid into a copolyester knit by employing an appropriate knitting machine attachment.
  • the invention can include dyeing the copolyester fibers at a temperature of less than about 116°C (240°F).
  • this reduction in dyeing temperature not only reduces energy usage, but also permits copolyester fibers that are produced according to this embodiment of the invention to be more effectively combined with spandex filaments.
  • Blended yams and fabrics that are made from PEG-modified copolyester fibers — preferably staple fibers or POY — and spandex fibers can be dyed at temperatures of less than about 116°C (240°F), and yet can achieve excellent fastness and depth of color.
  • the spandex fibers and the copolyester fibers may be dyed at a temperature of less than about 110°C (230°F). In another preferred embodiment, the spandex fibers and the copolyester fibers may be dyed at a temperature of less than about 104°C (220°F). In yet another preferred embodiment, the spandex fibers and the copolyester fibers may be dyed at or below a temperature of less than the boiling point of water at atmospheric pressure (i.e., 100°C or 212°F). In this regard, it should be understood that the concept of dyeing copolyester fibers and spandex fibers includes dyeing the blend in the form of blended yams and blended fabrics.
  • copolyester fibers are blended with cellulosic fibers, such as cotton fibers.
  • the preferred copolyester/cotton blends include between about 5 percent and 95 weight percent cotton fibers with the remainder comprising the copolyester fibers. Most preferably, the blend includes between about 30 weight percent and 70 weight percent cotton fibers with the remainder comprising the polyester fibers.
  • the invention provides the opportunity to increase the synthetic content of blended cotton and polyester yams to take advantage of the desirable characteristics of the copolyester in the resulting yams and fabrics.
  • the copolyester fibers formed according to the present method possess static-dissipation properties that are closer to that of cotton.
  • the present copolyester fibers retain the desirable dimensional stability characteristics of conventional polyesters.
  • a particular advantage of the present invention is that copolyester fibers and cellulosic fibers (e.g., cotton fibers) can be dyed in one step, which is expected to reduce dyeing and energy expenditures by 30 percent or more.
  • cotton is typically dyed using cotton dyes (e.g., reactive dyes) in alkaline dye baths and polyester is typically dyed at high temperatures (e.g. 129°C or 265°F) in acidic dye baths.
  • cotton dyes e.g., reactive dyes
  • polyester is typically dyed at high temperatures (e.g. 129°C or 265°F) in acidic dye baths.
  • dyeing blended cotton and polyester yams and fabrics requires a two-step dyeing process.
  • Such blends are usually dyed in an alkaline pH using suitable cotton dyes to selectively dye the cotton fibers and are thereafter dyed in an acidic pH using disperse dyes to selectively dye the polyester fibers.
  • the present copolyester fibers do not require any pH adjustment and can be dyed effectively in an alkaline dye bath having a pH as high as 10. Consequently, blended yarns and fabrics that are made from PEG-modified copolyester fibers and cotton fibers can be dyed simultaneously in an alkaline dye bath that includes both reactive and disperse dyes.
  • dyeing such cotton/copolyester blends is carried out in a dye bath having a pH of about 10 or less and a temperature at or below the boiling point of water at atmospheric pressure (i.e., 212°F or 100°C).
  • dyeing copolyester fibers and cellulosic fibers includes dyeing the blend in the form of blended yarns and blended fabrics.
  • Figure 11 describes the wicking properties of fabrics formed from copolyester fibers produced according to the invention as compared to the wicking properties of fabrics formed from conventional, unmodified polyethylene terephthalate fibers.
  • the copolyester fibers included between about 10 and 12 weight percent polyethylene glycol having a molecular weight of about 400 g/mol.
  • Wicking properties were measured using 2.5 cm x 15 cm (1 inch x 7 inch) strips that were suspended vertically above water-filled beakers and then submersed one inch below the water surface. After one minute, the water migration up the test strips was measured. The fabrics were tested in both fabric directions and averaged. The test strip fabrics were laundered once before testing. The room conditions were ASTM standard 21°C and 65 percent relative humidity.
  • Figure 12 describes the drying properties of fabrics formed from copolyester fibers produced according to the present invention as compared to the drying properties of fabrics formed from conventional, unmodified polyethylene terephthalate fibers.
  • the copolyester fibers included between about 10 and 12 weight percent polyethylene glycol having a molecular weight of about 400 g/mol. Drying rate was determined using a Sartorius MA30-000N3 at 40°C. Two or three drops of water were placed on the fabrics. Then, the evaporation time was measured and an evaporation rate was calculated. The room conditions were ASTM standard 21°C and 65 percent relative humidity.
  • Figure 13 describes the flame-retardancy properties of fabrics formed from copolyester fibers produced according to the invention as compared to the flame-retardancy properties of fabrics formed from conventional, unmodified polyethylene terephthalate fibers.
  • the copolyester fibers included between about 10 and 12 weight percent polyethylene glycol having a molecular weight of about 400 g/mol. The testing was performed in accordance with the NFPA 701 Method small-scale-after-flame test.
  • Figure 13 merely shows that fabrics formed from copolyester fibers produced according to the invention have better flame-retardancy properties as compared to those of fabrics formed from conventional, unmodified polyethylene terephthalate fibers.
  • Figure 13 is not intended to imply that fabrics formed from copolyester fibers produced according to the invention will meet any particular government flammability standards.
  • the copolyester fibers formed according to the present method possess static-dissipation properties that are closer to that of cotton.
  • Figure 14 describes the static-dissipation properties of fabrics formed from copolyester fibers produced according to the invention as compared to the static-dissipation properties of fabrics formed from conventional, unmodified polyethylene terephthalate fibers.
  • the copolyester fibers included between about 10 and 12 weight percent polyethylene glycol having a molecular weight of about 400 g/mol.
  • FIG. 15 describes the abrasion resistance properties of fabrics formed from copolyester fibers produced according to the invention as compared to the abrasion resistance properties of fabrics fo ⁇ ned from conventional, unmodified polyethylene terephthalate fibers.
  • the copolyester fibers included between about 10 and 12 weight percent polyethylene glycol having a molecular weight of about 400 g/mol.
  • the fabrics each had a TiO2 level of 3000 ppm.
  • Abrasion resistance was determined using Stoll flat (knits) ASTM D 3886 method and Taber (wovens) ASTM D 3884 method.
  • Figure 16 describes the strength properties of fabrics woven from copolyester fibers produced according to the present invention as compared to the strength properties of fabrics woven from conventional, unmodified polyethylene terephthalate fibers.
  • the copolyester fibers included between about 10 and 12 weight percent polyethylene glycol having a molecular weight of about 400 g/mol.
  • the somewhat weaker strength of fabrics formed from the fibers prepared according to the invention reduces undesirable pilling. Fabric strength was determined by strip test (wovens) ASTM D 1682-64 method or by Ball Burst (knits) ASTM D3787-80A.
  • Figure 17 summarizes on a percentage basis the improved properties of fabrics formed from copolyester fibers produced according to the invention as compared to the properties of fabrics formed from conventional, unmodified polyethylene terephthalate fibers.
  • the copolyester fibers included between about 10 and 12 weight percent polyethylene glycol having a molecular weight of about 400 g/mol.
  • the 30 percent improvement is based on darker shades.
  • fabric formed from 1.5 dpf copolyester fibers according to the present invention subjectively feels like fabric formed from 0.75 dpf conventional polyester microfibers. Note, too, that a tenacity of less than 3 grams per denier accentuates the superior tactility of fabrics formed from such copolyester fiber, and reduces the tendency of the fiber to pill.
  • copolyester fibers prepared according to the invention have dimensional stability properties, especially shrinkage during home laundering, that are substantially similar to those of conventional polyethylene terephthalate fibers.
  • conventional polyester fabric exhibits less than about five percent shrinkage in home laundering if finished at a temperature at or above 177°C (350°F).
  • copolyester fabric of the invention exhibits less than about five percent shrinkage in home laundering if finished (i.e., heat set) at a fabric temperature at or above 166°C (330°F). This is about the expected home laundering shrinkage of conventional polyester fabrics.
  • fabrics formed from the filaments spun according to the invention will possess better elastic-memory properties (i.e., stretch and recovery) as compared to fabrics formed from conventional polyethylene terephthalate filaments.
  • open fabric constmctions such as pique knits and low greige yam density wovens, tend to accentuate moisture movement and stretch performance.
  • the copolyester composition was polymerized like standard polyethylene terephthalate, except that the polymerization temperature was 10°C lower than normal.
  • Polyethylene glycol having an average molecular weight of 400 g/mole, was injected into the process before the initiation of the polymerization at a rate sufficient to yield 10 weight percent polyethylene glycol in the copolyester composition.
  • pentaerythritol was added before polymerization at a rate that would yield 500 ppm in the copolyester composition.
  • the copolyester was then extmded, quenched, and cut.
  • the quench water was 10°C colder than normal.
  • the copolyester was crystallized 10°C lower than normal.
  • the copolyester was melt polymerized to an intrinsic viscosity of 0.62 dl/g.
  • Solid State Polymerization The copolyester chip was solid state polymerized like a normal polyethylene terephthalate bottle resin chip except that the chip was maintained at 190°C for five hours. The intrinsic viscosity of the copolyester chip was increased in the solid phase to about 0.77 dl/g.
  • Filament Spinning The copolyester formed POY like a conventional polyethylene terephthalate product having the same filament count, except that the spinning speed was reduced by seven percent and the spimiing temperature was reduced by 15°C.
  • Dyeing was the same as conventional techniques except that no carrier was used and the batch was held at a dye temperature of 104°C (220°F) for 30 minutes.
  • Finishing was the same as conventional techniques except that the zone temperature was reduced 10°C and no finish was used in the pad.
  • the copolyester composition was polymerized like standard polyethylene terephthalate, except that the polymerization temperature was 10°C lower than normal.
  • Polyethylene glycol having an average molecular weight of 400 g/mole, was injected into the process before the initiation of the polymerization at a rate sufficient to yield 10 weight percent polyethylene glycol in the copolyester composition.
  • pentaerythritol was added before polymerization at a rate that would yield about 400 ppm in the copolyester composition.
  • the copolyester was then extmded, quenched, and cut.
  • the quench water was 10°C colder than normal.
  • the copolyester was crystallized 10°C lower than normal.
  • the copolyester was melt polymerized to an intrinsic viscosity of 0.78 dl/g.
  • Filament Spinning The copolyester formed POY like a conventional polyethylene terephthalate product having the same filament count, except that the spinning temperature was reduced by 10°C.
  • Fabric Formation was identical to conventional weaving and knitting techniques.
  • Dyeing was the same as conventional techniques except that no carrier was used and the batch was held at a dye temperature of 99°C (210°F) for 30 minutes. The heat-up rate was held to 1.1°C (2°F) per minute between 43°C (110°F) and 99°C (210°F) to ensure level dyeing.
  • Finishing was the same as conventional techniques except that the zone temperature was reduced 10°C and no finish was used in the pad.
  • Example 3 except for the following texturing modification.
  • the POY processed like standard polyethylene terephthalate POY except that the temperature was between about 50°C and 100°C below normal primary-heater temperatures. Finally, the secondary heater at 160°C was used to yield a set textured yarn.
  • Fabric Formation was identical to conventional knitting techniques.
  • the copolyester composition was polymerized like standard polyethylene terephthalate, except that the polymerization temperature was 10°C lower than normal.
  • Polyethylene glycol having an average molecular weight of 400 g/mol, was injected into the process before the initiation of the polymerization at a rate sufficient to yield ten weight percent polyethylene glycol in the copolyester composition.
  • pentaerythritol was added before polymerization at a rate that would yield about 500 ppm in the copolyester composition.
  • the copolyester was then extmded, quenched, and cut.
  • the quench water was 10°C colder than normal.
  • the copolyester was crystallized 10°C lower than normal.
  • the copolyester was melt polymerized to an intrinsic viscosity of 0.62 dl/g.
  • the copolyester chip was solid state polymerized like a typical polyethylene terephthalate bottle resin chip except that the chip was maintained at 190°C for five hours.
  • the intrinsic viscosity of the copolyester chip was increased in the solid phase to about 0.77 dl/g.
  • the copolyester formed staple fibers like a conventional polyethylene terephthalate product having the same fiber denier, except that the spinning speed was reduced by seven percent and the spinning temperature was reduced by 15°C. The drawing temperature was reduced approximately 15°C below that of normal polyester and the heat-setting temperature was reduced by 30°C.
  • Nonwoven Fabric Formation Carding was the same as for conventional polyester. Fabric formation was identical to conventional techniques, except that the optimum calendar bonding temperature was reduced by 20°C to 40°C. Hydroentangling, needlepunching, stitch-bonding, and through-air bonding (in the presence of low-melt binder fibers) methods may be the same as used on no ⁇ nal polyester fibers.
  • the copolyester composition was polymerized like standard polyethylene terephthalate, except that the polymerization temperature was 10°C lower than normal.
  • Polyethylene glycol having an average molecular weight of 400 g/mol, was injected into the process before the initiation of the polymerization at a rate sufficient to yield ten weight percent polyethylene glycol in the copolyester composition.
  • pentaerythritol was added before polymerization at a rate that would yield about 400 ppm in the copolyester composition.
  • the copolyester was then extmded, quenched, and cut.
  • the quench water was 10°C colder than normal.
  • the copolyester was crystallized 10°C lower than normal.
  • the copolyester was melt polymerized to an intrinsic viscosity of 0.78 dl/g.
  • the copolyester formed staple fibers like a conventional polyethylene terephthalate product having the same filament count, except that the spinning temperature was reduced by 15°C.
  • the drawing temperature was reduced by approximately 15°C below that of conventional polyester and the heat-setting temperature was reduced by 30°C.
  • Nonwoven Fabric Formation Carding was the same as for regular polyester. Fabric formation was identical to conventional techniques except that the optimum calendar bonding temperatures was reduced by 20°C to 40°C. Hydroentangling, needlepunching, stitch-bonding, and through-air bonding (in the presence of low-melt binder fibers) methods may be the same as used on normal polyester fibers.
  • Dyeing Dyeing was the same as conventional techniques except that no carrier was used and the batch was held at a dye temperature of 99°C (210°F) for 30 minutes. The heat-up rate was held to 1.1°C (2°F) per minute between 43°C (110°F) and 99°C (210°F) to ensure level dyeing. [00193] Finishing Finishing was the same as conventional techniques except that the zone temperature was reduced 10°C and no finish was used in the pad.

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  • Paper (AREA)
  • Polyesters Or Polycarbonates (AREA)
  • Nonwoven Fabrics (AREA)
  • Artificial Filaments (AREA)

Abstract

La présente invention concerne une fibre de copolyester modifié en polyéthylène glycol qui présente des caractéristiques de gestion de l'humidité exceptionnelles et qui peut être fabriquée en tissus exceptionnellement confortable. Cette fibre de copolyester comprend du téréphtalate polyéthylène en quantité suffisante pour que cette fibre de copolyester présente des propriétés de stabilité dimensionnelle sensiblement similaires à celles des fibres téréphtalate polyéthylène non modifié classiques, du polyéthylène glycol en quantité suffisante pour que la fibre de copolyester présente des propriétés d'effet mèche supérieures à celles des fibres téréphtalate polyéthylène non modifié classiques et un agent de ramification de chaîne en quantité inférieure à un équivalent molaire des ramifications d'environ 0,0014 mole par mole de polymère normalisé.
EP02704168A 2001-01-17 2002-01-16 Fibres de polyester modifie en polyethylene glycol Withdrawn EP1412565A1 (fr)

Applications Claiming Priority (5)

Application Number Priority Date Filing Date Title
US761446 2001-01-17
US09/761,446 US6582817B2 (en) 1999-11-19 2001-01-17 Nonwoven fabrics formed from polyethylene glycol modified polyester fibers and method for making the same
US827441 2001-04-06
US09/827,441 US6509091B2 (en) 1999-11-19 2001-04-06 Polyethylene glycol modified polyester fibers
PCT/US2002/001435 WO2002057523A1 (fr) 2001-01-17 2002-01-16 Fibres de polyester modifie en polyethylene glycol

Publications (1)

Publication Number Publication Date
EP1412565A1 true EP1412565A1 (fr) 2004-04-28

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Application Number Title Priority Date Filing Date
EP02704168A Withdrawn EP1412565A1 (fr) 2001-01-17 2002-01-16 Fibres de polyester modifie en polyethylene glycol

Country Status (2)

Country Link
EP (1) EP1412565A1 (fr)
TW (1) TW554099B (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
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CN115399533A (zh) * 2021-05-28 2022-11-29 耐克创新有限合伙公司 非织造缠结系统及制造方法

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Publication number Priority date Publication date Assignee Title
US12501952B2 (en) 2021-05-28 2025-12-23 Nike, Inc. Nonwoven textile garment arrays and methods of manufacturing the same
US12325938B2 (en) 2021-05-28 2025-06-10 Nike, Inc. Nonwoven entanglement system and methods of manufacture
US12342885B2 (en) 2021-05-28 2025-07-01 Nike, Inc. Nonwoven textile with non-linear entangled seams suitable for garments

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO02057523A1 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115399533A (zh) * 2021-05-28 2022-11-29 耐克创新有限合伙公司 非织造缠结系统及制造方法

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