MXPA97003353A - Polyamide fibers, resistant to stains, and articles that understand mis - Google Patents

Abstract

The present invention relates to a carpet resistant to staining of dyes and coffee, has bicomponent surface wrap / core fibers, fixed in a backing material and units there. These surface fibers have a core of a first polyamide component and an envelope which covers, substantially or completely, the core of a second polyamide component, which is inherently chemically compatible with the first polyamide component. In a colorless state, the carpet has a red drink dyeing depth of less than 15 EI units of CIE and a depth of coffee staining of 10 EI units of CIE, approx.

Description

FIBERS OF P0L1AM1DA. RESISTANT TO STAINS. AND ARTICLES THAT INCLUDE THE SAME FIELD OF THE INVENTION This invention relates to polyamide fibers, resistant to stains and articles composed of such fibers. More particularly, this invention relates to articles, such as carpets, containing stain-resistant bicomponent wrap / core fibers, which have a sheath of a first polyamide composition and a core of another polyamide composition. BACKGROUND OF THE INVENTION The terms "stain" and "stain," as used herein with respect to polyamide fibers, mean the discoloration of such fibers, caused by the agglutination of a colored material, or ionically, covalently or through from the chemical division, to the fiber. The term "stain resistant" or "stain resistance", as used herein with respect to polyamide fibers or carpets, refers to the ability of the fibers or a carpet to resist stains of red beverages and of the coffee. "Depth of staining of red beverages" refers to the total CIÉ color difference (? E), between stained and unstained carpets, as quantified by the use of a spectrophotometer, when carpets have been stained or stained in accordance with the AATCC method 175-1992. Red drinks are commonly used as an exemplary stain of acid dye type. The "coffee stain depth" refers to the total CIÉ color difference (? E), between the stained and unstained carpets, as measured using a spectrophotometer, when the tapestries are stained by the AATCC method 175-1992, except that 5.6 g / 1 of Folger's® instant coffee (150SC) replace the red drink. "Chemically compatible inherently" means that the mentioned materials are irascible. Polyamide fibers are relatively inexpensive and offer a combination of convenient quantities, such as comfort, warmth and ease of manufacture in a wide range of colors, patterns and textures. As a result, polyamide fibers are widely used in a variety of household and commercial articles, including, for example, carpets, curtain material, upholstery and clothing. Carpets made of polyamide fibers are a popular floor covering for both residential and commercial applications. However, polyamide fibers tend to be easily stained or easily stained permanently by certain natural and artificial colorants, such as those found in common household beverages, such as coffee, wine and non-alcoholic beverages. These household drinks may contain a variety of anionic color compounds, which include acid dyes. The dyeings resulting from such compounds can not be easily removed under ordinary cleaning conditions. The ability of a dyeing material, such as an acid dye, to bond to the fiber, is a function of the type of functional groups active in the fiber and the dyeing material. For example, polyamides usually have amine end groups that bind with the negatively charged active groups in an acid dye (or dyeing agent). An acidic dye, commonly used, and one which severely stains nylon at room temperature, is C.I. Food Red 17, also known as FD &C Red Dye 40. Acid dyes, such as C.I. Food Red 40 often form strong ionic bonds with the protonated terminal amine groups in the polyamide polymers, thus staining, ie staining the fiber. Therefore, in contrast to dirt capable of being physically removed from polyamide carpets by recognized cleaning procedures, and acid dye colorants, such as C.I. Food Network 17, penetrate and chemically react with the polyamide to form bonds there that make the complete removal of such dyes from polyamide fibers impractical or impossible.

The exact mechanism of coffee as a staining agent is not well understood. However, as with stains of acid dyes, coffee stains are notoriously difficult to remove with conventional cleaning procedures. This severe staining of carpets is a major problem for consumers. In fact, research shows that more carpets are replaced due to staining than because of wear. Therefore, it would be convenient to supply polyamide fibers that resist common domestic stains, such as acid and coffee dye, thus increasing the life of the carpet. Methods for decreasing the affinity of acid dye to nylons are known. For example, U.A. Patent No. 3,328,341 to Corbin, et al., Describes reducing the staining of nylon with butrylactone. The patent of E. U. A., No. 3,846,507 to Tho m et al., Describes reducing the affinity to the acid dye of the polyamide by mixing a polyamide with a polymer having benzenesulfonate functionality. U.A. Patent No. 5,108,684 to Anton et al. Describes fibers made of nylon copolymers, containing 0.25 to 4.0 weight percent of an aromatic sulfonate, which are resistant to acid dye stains. In the patent of E. U. A., No. 5,340,886, Hoyt et al. describe resistant nylon fibers of acidic dyes, obtained by incorporating in the polymer sufficient SO3H groups or their salts, to give the polymer a sulfur content between approximately 1 and 160 equivalents per 106 grams of the polymer and, chemically blocking with a blocking agent chemical a portion of the amine end groups present in the sulfonated polymer. Modified polymers, such as those described in these patents, are generally expensive to obtain. In addition to polymer modifications, topical treatments for carpets have been proposed as a cost effective resource for imparting resistance to acid dyes to polyamide carpet fibers. These topical treatments can be sulfonated materials that act as "colorless dyes" and bind to the amine dye sites in the polyamide polymer. Sulfonated products for topical applications to polyamide substrates are described, for example, in U.S. Patent No. 4,963,409 to Liss et al .; U.A. Patent No. 5,223,340 to Moss, III et al .; U.A. Patent No. 5,316,850 to Sargent et al .; and U.A. Patent No. 5,436,049 to Hu. Hu also discloses a nylon substrate which is derived from a nylon polymer blended in a molten form with a reducing compound of an amine end group, prior to the formation of fibers. Topical treatments tend to be non-permanent and wash with one or more shampoos.

Fibers can be formed in a variety of configurations and from a variety of materials. For example, some fibers have more than one type of polymer in portions other than the cross section and extend the length of the fiber. Fibers having two such portions are known as "bicomponent fibers". These bicomponent fibers having one of the portions surrounding or substantially surrounding the other, are named as having a shell and core configuration. The bicomponent polyamide wrapper / core fibers are known. U.A. Patent No. 5,445,884 to Hoyt and Wilson, discloses a filament with reduced staining ability, having a polyamide core and a hydrophobic polymer sheath. The weight ratio of the core to the envelope is approximately 2: 1 to 10: 1. If the envelope is very thin, a compatibilizer should be used. These compatibilizers are generally expensive. The compatibilizer can, in many cases, be eliminated by making the wrap relatively thick, ie more than 15% by weight of the cross section. However, if the wrapping material is expensive, can also be added significantly to the cost of the fibers. U.A. Patent No. 4,075,378 to Anton describes bicomponent sheath / core polyamide fibers which contain a polyamide core and a polyamide shell. The core polyamide can be dyed in acid form while the polyamide in the shell is stainable in basic form, due to sulfonation. U.S. Patent No. 3,679,541 to Davis et al. Describes a bicomponent wrap / core filament, having soil release, anti-redeposition and anti-static properties, through the use of a copolyester wrap or copolyamide around a polyamide core. U.A. Patent No. 3,645,819 to Fuji et al. Describes bicomponent polyamide fibers for use in tire cords, bowstrings, fishing nets and racquet ropes. The fibers of Fuji are round of configuration of "multiple nuclei" or of type "islands in the sea". U.A. Patent No. 3,626,183 to Brayford discloses bicomponent wrap / core polyester fibers, which have antistatic and dirt release characteristics. U.S. Patent No. 2,989,798 to Bannerman describes bicomponent wrap / core fibers that are said to have improved dyeability by modifying the level of the terminal amine group of the shell relative to the core. The envelope has fewer amine end groups than the core.

The fibers that are not round in cross section are known. For example, the patents of E. U. A., Nos. 2,939,202 and 2,939,201, both of Holland, describe fibers having a trilobal cross-section. SUMMARY OF THE INVENTION The present invention relates to carpets resistant to stains of acid and coffee dyes. The carpet comprises a backing material with a bicomponent wrap / core surface fibers, resistant to stains of acid and coffee stains, fixed in this backing material and bonded there. The surface fibers have a core of a first polyamide component and a shell, which covers, substantially or completely, the core, of a second polyamide component, and which is chemically compatible inherently with the first polyamide component. The second polyamide component comprises at least one stain resistant polyamide polymer, selected from the group comprising: (a) [NH- (CH2)? - NH-CO- (CH2) y -CO] n where x and y can be integers equal or different from about 4 to 30, and the sum of x and y is greater than 13, and n is greater than about 40; and o II (b) [NH- (CH2) Z-C-] m where z is an integer from about 9 to 30, and m is greater than about 40; (c) derivatives of (a) or (b), which include polymers substituted with one or more sulfonate, halogenate, aliphatic or aromatic functionalities; and (d) copolymers and mixtures of (a), (b) and (c). In a colorless state, does the carpet have a red drink dyeing depth of less than 15 units? E CIÉ and a coffee dyeing depth of less than 10 units? E CIÉ. It is an object of this invention to provide carpets that resist dyeing by acidic dyes. It is another object of this invention to provide carpets that resist staining by coffee. Another object of this invention is to provide carpets, which also have good stain resistance properties and are economical to manufacture. Still another object of the present invention is to provide a carpet obtained from fibers exhibiting a reduced shrinkage stable to the steam heat of water. The carpets of this invention are economical, durable and have a final dyeing resistance usually caused by acidic dyes and by coffee. Also, since the chemical nature of the fibers used to obtain the carpet makes them resistant to stains, this stain resistance of the fibers is permanent. Because the relatively expensive stain resistance characteristic can be present only in a relatively thin envelope, and production costs are retained. This integration of stain resistance is a significant improvement over topically applied stain resistant agents. These and other objects and advantages that are achieved by the present invention will be readily apparent to those skilled in the art from the following description. BRIEF DESCRIPTION OF THE DRAWING Figure 1 is a bar graph showing the red beverage dyeing depth, expressed in terms of the? E values, of various carpets, including the carpets used in the invention. Figure 2 is a graph of bars showing the depth of staining of coffee, expressed in terms of values? E, of various carpets including the carpets used in the invention. Figure 3 is a bar graph showing, in steady shrinkage, water vapor heat, of various yarns, including the yarns used in the invention.

DETAILED DESCRIPTION OF THE INVENTION To promote an understanding of the principles of the present invention, follow descriptions of the specific embodiments of the invention and the specific language used to describe them. However, it will be understood that there is no attempt to limit the scope of the invention by the use of specific language. Alterations, subsequent modifications and such further applications of the discussed principles of the invention are considered., as will normally be apparent to those skilled in the art to which the invention pertains. Carpets obtained in accordance with the present invention resist stains caused by both acid and coffee stains. These rugs are obtained from bicomponent polyamide surface fibers, composed of a polyamide core phase, which is substantially or completely surrounded by the stain resistant polyamide wrapping phase. The fibers of this invention preferably contain from 97 to 10% by weight of the core phase and from 3 to 90% by weight of the shell phase. More preferably, the fibers used in the carpet of this invention contain about 90 to 70% by weight of the core phase and about 10 to 30% by weight of the shell phase. More preferably, the fibers contain from about 90 to 85% by weight of the core phase and from about 10 to about 15% by weight of the shell phase. The core and sheath polyamides of the fibers can be formed from any linear polyamide or copolyamide that forms fibers, or from any monomer that forms polyamides, while the sheath polyamide (ie, "the second polyamide component") is resistant to spots. Suitable polyamides, which form fibers, for use in the present invention, include polymers having, as an integral part of the polymer backbone chain, recurring amide groups (-C0-NR-), where R is a substituent of alkyl, aryl, alkenyl or alkynyl. Non-limiting examples of such polyamides include the homopolyamides and the copolyols obtained by the polymerization of the lactam or the aminocaproic acid or a copolymerization product of any of the possible permutation mixtures of the diamines, dicarboxylic acids or lactams. The core polyamide (ie, "the first polyamide component") of the fibers used in this invention can be a dyeable polyamide in acid form, such as a polyamide having amine end groups available for the dyeing sites. Such polyamides and methods for their formation are well known to those of ordinary skill in the art. Preferred exemplary core polyamides include nylon 6 and nylon 6,6. Other polyamides, such as nylon 12, nylon 11, nylon 6/12, nylon 6/10, etc. they have been modified so that they become dyeable with acidic dyes or coffee, they can be used. More preferably, the core polyamide is nylon 6 or nylon 6/6. Possibly the core polyamide can have a terminal amine group content of more than about 5 milliequivalents per kilogram (meq / kg) to less than about 100 milliequivalents per kilogram, more preferably from about 20 to 50 milliequivalenets, per kilogram. Those of ordinary skill in the art will readily recognize that the amine end groups in the polymer chain include secondary or tertiary amine groups. Secondary and tertiary amines can be detected in the potentiometric titration curves for the amine end groups as a second weak break. The term "equivalents" of amine includes all the amine groups that can be titrated (primary, secondary and tertiary) detected. The wrapping phase of the fiber is composed of a second component of polyamide. This second polyamide component includes a polyamide polymer resistant to acid and coffee dye stains. The polyamide used in the wrapper is resistant to acidic dyes, so that, when the surface fibers are exposed to IC Red No. 17, the dyeing depth of red beverages of the surface fibers is 15 or less units? of CIÉ, under the name Daylight 6500 Standard Illuminant. More preferably, the dyeing depth of red drinks is about 10 or less units? E. The wrap polyamide is resistant to coffee stains, such as when surface fibers are exposed to coffee, the staining depth of coffee under the Daylight 6500 Standard Illuminant standard is approximately 10 or less CI? E units. The shell polymer can be a polyamide selected from the group consisting of polyamides having the structure: (a) [NH- (CH2)? - NH-CO- (CH2) y -CO] n where x and y can be the same or different integers, preferably from about 4 to 30, and the sum of x and y is greater than 13, more preferably from about 9 to 20, and especially preferred from about 9 to about 15, and n is greater than approximately 40; Y OR II (b) [NH- (CH2) Z-C-] m wherein z is an integer from 9 to 30, approximately, more preferably from 9 to 20, approximately, and especially preferred from 9 to 15, and m is greater than approximately 40; (c) derivatives of (a) or (b), which include polymers substituted with one or more sulfonate, halogenate, aliphatic or aromatic functionalities; and (d) copolymers and mixtures of (a), (b) and (c). Preferred shell polymers have more than 80% non-carbonyl skeleton or substituent carbons, such as alkyl, alkenyl, alkynyl, aryl, fluoroalkyl, fluoroalkenyl, fluoroalkynyl, fluoroaryl, chloroalkyl, chloroalkenyl, chloroalkynyl, chloroaryl, and the like, and they do not have polar substituents, such as hydroxy, amino, sulfoxyl, carboxyl, nitrosyl or other functionalities capable of binding to hydrogen. Non-limiting examples of fiber-forming polyamide adaptase which can be used as the polyamide component of the shell include nylon 6/10, nylon 6/12, nylon 11 and nylon 12. The shell polyamide which forms fibers can be sulfonated but, preferably, in substantial form, it is free of sulfonate. More preferably, the shell polymer is nylon 6/12. The sheath polyamide component may have a blocked amine terminal group and preferably so. The polyamide polymer preferably in the phase of the fiber wrap has a titratable concentration of the amine end group less than 30 meq / kg, more preferably less than 15 meq / kg, and especially preferred less than 5 meq / kg, approximately . Such a polyamide polymer blocked in the amine end group can be prepared, for example, by the reaction of the fiber forming polyamide (for example, one of the polyamides forming fibers listed hereinabove) with a blocking agent of the terminal group of amino, to chemically blot a number of amine end groups present in the polyamide. The blocking agent of the amine terminal group can be incorporated into the polyamide which forms fibers in a number of ways. For example, the agent can be added directly to the melt of the polymer prior to fiber formation. In one method, the agent is added to fragments of the polyamide prior to the formation of the melt. Preferably, the blocking agent is added to the polyamide fragments immediately after the fragments have been dried in a rotating drum, to remove excess moisture and, therefore, are still hot, for example they have a temperature of 90 to 952C. . The fragments and blocking agent are completely stirred or mixed in a different manner to produce a uniform mixture of fragments and blocking agent, prior to the formation of the melt. The fragments are then passed to a conventional mixing device and extruded at an appropriate temperature, which is preferably a temperature ranging from 265 to 300 ° C. In another method, the blocking agent of the amine terminal group is introduced by means of a dosing device to a conventional device of the melt together with fragments of the polyamide. The polyamide and the blocking agent are then melted together. Suitable blocking agents of the amine terminal group are known to those of ordinary skill in the art, and include, for example, lactones and anhydrides. Examples of anhydrides that can serve as blocking agents for the amino terminal group in this invention include, for example, acetic anhydride, maleic anhydride, glutaric anhydride, benzophenone tetracarboxylic dianhydride, naphthalene tetracarboxylic dianhydride, benzenecarboxylic dianhydride, cyclobutan-tetracarboxylic dianhydride, succinic anhydride, benzoic anhydride, acetic-formic anhydride, and other carboxylic anhydrides. Preferred blocking agents of the amine end group for use in the present invention are the lactones, more preferably the caprolactones and butyrolactones. More preferably, the blocking agent of the amine terminus group used in the present invention is an epsilon-caprolactone.

The amount of the blocking agent of the amine end group added to the fiber forming polyamide to obtain the shell polyamide polymer depends on the desired results and the particular polyamide used. Preferably, amounts exceeding 0.02% by weight, based on the weight of the polyamide, will be used. While there is generally no upper limit to the amount of the blocking agent of the terminal amine group that can be added, it is currently preferred that the amount used does not exceed 3% by weight, based on the weight of the polyamide. For example, the epsilon-caprotactone is used as the blocking agent, the amount of the epsilon-caprolactone will preferably vary from 0.5 to 2% by weight, based on the weight of the polyamide. Optionally, the fiber can be dyed in solution by the incorporation of one or more dyes in the polymer, before spinning the fiber. As used herein, the term "dye" refers to a color agent which is a water-soluble dye, soluble in organic substances, a dye soluble in the polymer, a pigment or any other agent imparting color. The dyes are generally introduced in the form of a concentrate formulation containing one or more "pure" dyes in the polymer matrix. The number, color and quantity of the added dyes are dependent on the desired final color. In addition, the usual fiber additives (for example delustrants, antioxidants, heat stabilizers, etc.) can be added to the polyamides, before spinning. As previously mentioned, the wrapping phase preferably, substantially or completely, covers the core of the fiber used in this invention. Methods for forming sheath / core fibers are known to those skilled in the art. A method referred to for forming the wrap / core fibers is described in U.S. Patent No. 5,162,074 to Hills, which is incorporated herein by reference for the bicomponent spinning techniques taught therein. The wrap / cover arrangement can be eccentric or concentric. The fibers used as surface fibers in the carpet of this invention are preferably multilobal. Trilobal cross sections are currently preferred. The common melt spinning and then the process techniques, can be used to obtain the fibers. The fibers can be crimped to produce bulky yarns by known methods, including the crimping of the tow box, gear curl, edge curl, false twist texturing and hot fluid jet volume.

The fibers used in this invention can be continuous or short fibers, alone or in admixture with other fibers, particularly when stain resistance is important. The fibers are particularly useful as continuous threads of bulky filaments. The carpet of the present invention can be obtained by conventional carpet manufacturing techniques, such as weaving or curling the surface fibers into a backing material and attaching these surface fibers to the backing with latex or other adhesives. The carpet of the present invention may have a backing of a foam. It can also be a curled or level tie. The carpet of the present invention may be in the form of carpet tiles, with or without foam backing. The carpet of the present invention can be manufactured according to standard techniques for obtaining cut pile carpets, well known to those skilled in the art. For example, the envelope / core fibers, described above, can be formed into a yarn, twisted and heat stabilized. Various ends can be combined in a variety of ways and levels of twisting according to conventional techniques. Then it is curled on a primary backing and cut to form the cut pile carpet. This primary backup can be jute, nylon, polyester, polypropylene, etc., woven or non-woven, the trimmed pile carpet is dyed to the desired shade. A secondary backing adheres to the hairless side, typically using a latex-based adhesive. Secondary backing can be jute, polypropylene, nylon, polyester, etc. The carpet of the present invention may be of a variety of hair weights, hair heights and styles. It is not currently believed that there is any limitation in the style of the carpet. Nylon threads will often shrink during thermal stabilization. Preferably, the fiber used in this invention has a shrinkage value in thermal stability with water vapor of about 70% or less, relative to the shrinkage value of thermal stabilization and water vapor of the fiber, which is manufactured in the manner indicated, but consisting only of the polyamide component of the core. The invention will now be described with reference to the following detailed examples. These examples are indicated by way of illustration and do not attempt to limit the scope of the same. Knit fabrics were used in some of the following examples to demonstrate the stain resistance nature of the fibers useful in making the carpets of the present invention. This is merely for illustration and it is believed that the fibers will exhibit substantially identical attributes as the surface fibers in the carpet. EXAMPLES 1-3 In Examples 1-3, six (6) fabric samples, prepared from three (39 different types of polyamide fibers, were tested on the stain resistance of acid and coffee dyes) Examples 1 and 3 are samples of comparative fabrics Example 2 was prepared according to the invention For Examples 1-3, a yarn of bicomponent, round, 52 filament, 3520 denier fibers was prepared by the joint melt spinning of the polyamide of the shell core and polyamide, using a 52-hole concentric sheath / core spin pack, fed by two extruders The 52-strand yarn, 3520 denier, was stretched and textured by fluid jet using a conventional element known to those skilled in the art, to a final denier of 940. Each textured yarn was knitted in a cloth sample, The respective fibers obtained in the examples are as follows: Example 1 (comparative): bicomponent fibers they have a n "nylon core 6" and a "shell" of nylon 12, with a shell weight ratio: core of 50:50, but the shell does not form a continuous shell on the core.

Example 2 (invention): bicomponent fibers having a nylon core 6 and a nylon sheath 6/12, with a shell: core weight ratio of 50:50. Example 3 (comparative): nylon 6 was spun into both the core and the sheath, at a weight ratio of 50:50. This example represents the typical monocomponent fibers. The acid and coffee stain resistance of the various fabric samples of Examples 1-3 were determined as described. The total color differences, given as values? E, between the stained and unstained samples, were calculated using the CIÉ L * a * b * system, as described by the Commission Internationale de l'Eclairage, in the publication of CIÉ No. 15 (E-1.3.1) for the Daylight 6500 standard illuminant. The results are given in Table i. In general, in the method used in Examples 1-3, a value of? E less than 5 is considered simply unstained; a value of? E of 5 to 10 indicates a very low dyeing; and a value of? E greater than 10 is considered to be significantly dyed. However, for colorless or slightly colored substrates (carpets or fabrics), the dyes may have a greater overall color difference than those given above and may serve as very acceptable anti-dye substrates, when used in deeper color materials. . The carpet or fabric without color serves as an example of the "worst case". A color substitute masks the degree of color change due to dyeing. Resistance of the Coffee Stain The fabric samples, prepared in the Examples 1-8, they were tested on stain resistance to coffee. The stain resistance tests of the coffee were carried out in the following manner. A coffee beverage was prepared using 5.6 g per liter of Folger's® instant coffee, which was heated to 65.52C. Each sample of fabric to be tested was covered with an amount of instant coffee liquid so that the coffee mass is 1 to 2.5 times the mass of the fabric sample. The spots were allowed to remain on the fabric samples for 20 (10) minutes, after which the fabric samples were dried for 24 hours. After 24 hours, the samples were rinsed with cold water, extracted and dried by rotation. The results of the coffee stain resistance tests for the fabric samples prepared in Examples 1-3 are presented in Table I. Stain Resistance of C.I. Food Red 17: The red beverage stain resistance tests in Examples 1-3 were carried out as follows: A solution of 80 mg of FD &C Red No. 40 (C.I. Food Red 17) per liter of water was prepared. Each sample was placed individually in a bath ratio of 19: 1 of the C.I. Food Network 17, for 5 minutes at room temperature. After five minutes, the samples were removed, lightly squeezed by hand to remove the excess liquid and left to dry for 16 hours. After 16 hours, the samples were rinsed with cold water, extracted and dried by rotation. The results of the coffee stain resistance tests, carried out in Examples 1-3, are presented in the following Table I. TABLE I Stain Resistance Analysis Examples 1-3 Examples 4-89 In Examples 4-8, the dyeing depth of the red beverage was measured by the spectrophotometer in the stained samples according to Method 175-1922 of the AATCC.

The dyeing depth of the coffee was measured by the spectrophotometer in stained samples according to the method 175-1992 of AATCC, except that 5-6 g / 1 of the Instant Coffee Folger's®, at 65.52C, replaced the red drink. Example 4 (Comparative) Using nylon 6 (relative viscosity of 2.7, amino end group level of 37 milliequivalents / kg) a bulky, textured (BCF), 58 filament, 1100 denier continuous fiber yarn, was spun using a Stretch and texture spinning machine (SDT) and conventional nylon 6 spinning conditions. A trilobal row was used so that the filaments had a trilobal cross section known as "fox" cross section, due to its resemblance to a fox head. The temperature of the polymer in the spin pack is 2702C. A stretch ratio of 2.8 was used. The speed of the wire feeder was 2400 meters per minute. Examples 5-8 (invention) Bicomponent yarns with nylon sheath 6.12 (Vestamid ™ D16, from Hüls America, Inc., of Piscataway, NJ) and nylon 6 core, were obtained as described in Example 4, using a two-component spin pack. The ratio of the shell polymer to that of the core varied as shown in Table II. The extrusion temperature of nylon 6.12 is 2702C.

The threads of Examples 4-8 were knitted in single plain jersey flat fabrics. These fabrics were stained using the AATCC test procedure 175-1992, where the knitted fabric replaced the floor covering of the process hair. A method of classifying the dyeing performance is different from the AATCC 175-1992. A spectrophotometric measurement of the dyed and non-dyed materials was made and the total color difference between the dyed and non-dyed materials was calculated under the CIÉ L * a * b * system. For details of this calculation, see, for example, Billmeyer, Principles of Color Technology. The lower the value of the total color difference (? E), the better the resistance of the material to the dyeing. The results are presented in the table. II. Knitted fabrics not dyed were also stained with coffee. The degree of staining was determined using the same method described for the spots of the red drink, immediately before. The results are presented in table II. The wires of Examples 4-8 were twisted in wire to produce a twist level of 3.75 tpi (twisted per inch) (1476 twisted per cm). This twist is then stabilized by heat using an autoclave. The heat-stabilized yarns curled on a 1/8 gauge machine to produce a hair height of 14.29 mm and a weight of 1187 g / m2 of the surface yarn on a trimmed pile mat. The depth of staining of the red drink and the staining of the coffee of each carpet were measured. The results are presented in Table II. Skeins of wired wires were heat stabilized in a steam autoclave, using a temperature cycle of 132SC - 1102c - 1322C - lice - 1322C. The denier (or linear density) was determined using the ASTM D1059 standard, where the yarn length used is 90 cm. The autoclave shrinkage was calculated using the linear densities before and after the heat setting of the yarn and using the formula: shrinkage = (after "dantes) / after where dantes and after are the linear densities before and after the thermal stability treatments (Superba shrink or Autoclave) The results are presented in Table 2. Figures 1-3 graphically illustrate the results of the stain depth of the red tint, the coffee stain depth and the water vapor heat stabilized shrinkage.

TABLE III Examples 4-8 Dye Differences Total Color Difference (? E of CIÉ L * a * b *)

Claims (19)

1. CLAIMS 1. A carpet resistant to stains of acid dyes and coffee, which includes: a backing material; and surface wrap / core, bicomponent, stain resistant, fixed fibers in the backing material and bonded therein, these surface fibers have a core of a first polyamide component and a sheath, which covers, substantially or completely, the core and of a second polyamide component, which is chemically compatible, inherently, with the first polyamide component, this second polyamide component comprises at least one polyamide polymer, resistant to staining, selected from the group consisting of: (a) [NH- (CH2)? - NH-CO- (CH2) y -CO] n where x and y can be integers equal or different from about 4 to 30, and the sum of x and y is greater than 13, and n is greater than about 40; Y
2. OR
3. II (b) [NH- (CH2) Z-C-] m where z is an integer from about 9 to 30, and m is greater than about 40; (c) derivatives of (a) or (b), which include polymers substituted with one or more sulfonate, halogenate, aliphatic or aromatic functionalities; and (d) copolymers and mixtures of (a), (b) and (c). this carpet, in a colorless state, has a dyeing depth of red drinks of less than 15 units of CIÉ and a depth of coffee staining of less than 10 units? E CIÉ. 2. The carpet of claim 1, wherein the second polyamide component has a concentration of titratable amino end groups, less than 30 railiequivalents per kilogram. The carpet of claim 2, wherein the concentration of the titratable amino end groups in the second polyamide polymer is less than 5 milliequivalenets per kilogram.
4. 4. The carpet of claim 1, wherein the second polyamide polymer is substantially free of sulfonate.
5. 5. The carpet of claim 1, wherein the second polyamide polymer is nylon 6/12 or nylon 12.
6. 6. The carpet of claim 1, wherein the non-polar functional groups comprise more than 80% of the carbon atoms of the non-carbonyl polymer. The carpet of claim 1, wherein the first polyamide component is selected from the group consisting of: nylon 6, nylon 12 nylon 11, nylon 6/6, nylon 6/12, nylon 6/10, and combinations thereof . The carpet of claim 1, wherein the first polyamide component is nylon 6/6 or nylon 6. 9. The carpet of claim 3, wherein the first polyamide component has a concentration of terminal groups of amine greater than about 5 and less than about 100 milliequivalents per kilogram. 10. The carpet of claim 9, wherein the first polyamide component has a concentration of amine end groups of about 20 to 50 milliequivalents per kilogram. The carpet of claim 1, wherein the fibers comprise about 10 to 97% by weight of the core phase and about 90 to 3% by weight of the shell phase. The carpet of claim 11, wherein the fibers comprise about 85 to 90% by weight of the core phase and about 15 to 10% by weight of the envelope phase. 13. The carpet of claim 1, wherein the fibers have a non-round cross section. 14. The carpet of claim 1, wherein the fibers have a multilobal cross section. 15. The carpet of claim 1, wherein the fibers have a trilobal cross section. The carpet of claim 1, wherein the fibers have a value of the thermal stability shrinkage of water vapor, which is about 70% or less of the shrinkage value of water vapor thermal stability of fibers, identical otherwise, they consist only of the first polyamide component. 1
7. 7. The carpet of claim 1, wherein the dyeing depth of the red beverage is less than about 10 units of? E. 1
8. 8. The carpet of claim 1, wherein x, y and z are each not greater than 20. The carpet of claim 1, wherein x, y and z are each not greater than 15.