RU2278187C2 - Improved synthetic fibers based on polyolefins and a method for fabrication thereof - Google Patents

Abstract

FIELD: polymer materials and textile industry.

SUBSTANCE: invention relates to fabrication of fibers and yarns possessing improved dyeability with reactive and disperse dyes, resistance to pollution, and improved mechanical characteristics. Method comprises blending polyolefin polymer and fibril-forming polymer to form blend of polyolefin polymer and fibril-forming polymer. Blend is fed into hot-melt extruder to produce essentially homogenous molten blend of the two polymers. Molten blend is forced through die having length-to-diameter ratio between about 3 to about 30 to produce fiber having polyolefin matrix and elongated essentially interrupted fibrils of fibril-forming polymer, which are dispersed in polyolefin matrix, and thereby outside surface of fibers is essentially fibril-free. Thus fabricated fibers are useful as yarn for face side of tappets, textiles, upholstery material, and other industrial applications such, for example, as chemical industry.

EFFECT: improved consumer's quality of fibers and yarn.

30 cl, 11 dwg, 6 tbl, 9 ex

Description

Field of Invention

The invention relates to synthetic yarn based on a polyolefin, characterized by improved mechanical properties, improved dyeability, and a method for producing yarn for the manufacture of the front side of carpets, textiles and upholstery.

Prior art

This invention relates to the invention described in application with registration number 08/787241 in the name of Mallonee, filed January 24, 1997, now US patent No. 5811040, which is a partial continuation of the application with registration number 08/339336 in the name of Mallonee, filed November 14, 1994, now US patent No. 5597650, and a partial continuation of the application with registration number 08/523470 in the name of Mallonee, filed September 5, 1995, now US patent No. 5620797.

The invention also relates to application with registration number 08/407507 in the name of Mallonee, filed March 14, 1995, now US patent No. 5587118.

Polyolefin-based yarns are characterized by low cost and chemical resistance to many liquids and, therefore, are of interest for the manufacture of carpets and textile products, including upholstery yarn, where dyeing is a problem. Polyolefin-based yarns are also suitable for technical applications such as filters. However, there are several drawbacks to conventional yarn and polyolefin-based fibers. For example, the glass transition temperature (Tg) is lower than room temperature (i.e., between -5 and -15 ° C). Due to the low Tg of the polyolefin-based yarn, shape stability under external load at room temperature is limited. Polyolefin-based yarn tends to adapt to a new form due to molecular motion in the polymer. As a result, the elasticity of carpets made with polyolefin-based yarn is undesirably low for use as fiber for carpet products. The elasticity and other mechanical properties of the yarn are low even at temperatures higher than room temperature. Curing by heating the polyolefin-based yarn makes it possible to relax the internal stresses of the yarn fibers and allows the yarn to remain in shape after torsion, but curing by heating cannot result in a stable yarn shape if sufficient external stress is applied.

Another disadvantage of polyolefin-based yarns is that the yarn is only slightly dyed by dispersed dyes and not at all dyed by reactive (active) dyes. The color fastness of such yarns is often unsatisfactory even when washing the yarn at low temperature.

Of the other synthetic fibers, nylon was the primary fiber for carpet making, where high quality and elasticity are required. However, nylon is not a fiber without flaws. It is known that a carpet made with nylon yarn is prone to the formation of static electric charges and therefore must be chemically or physically processed to reduce the formation of static charges. Other disadvantages of nylon carpet are that it is easily dirty. Accordingly, a nylon carpet is usually subjected to treatments that reduce its tendency to become dirty. Such treatment, however, does not prevent all contamination, and treatment will not be effective for the entire life of the carpet.

On the other hand, carpets made from polyolefin materials such as polypropylene are very resistant to contamination and are antistatic in nature. However, as indicated above, polypropylene is a less durable fiber and cannot retain its appearance or shape when prolonged use or use under severe conditions or after repeated deformations.

Similar arguments for polyolefin-based yarns can be addressed to textiles, including upholstery yarns, where dirt removal is particularly difficult. The use of polyolefin-based yarn can be even more beneficial due to the low cost of the polymer and its excellent water resistance, dry strength and resistance to contamination. Unfortunately, the use of polyolefin-based yarns is limited by its low mechanical properties and limited shape retention due to the low elasticity of such yarns and the fact that the mechanical properties of such yarns at temperatures above room temperature tend to decrease rapidly.

Standard methods of dyeing using a dye bath are not possible for polyolefin-based yarns, as are possible with polyester or nylon fibers. Accordingly, polyolefin polymers or copolymers, such as copolymers of ethylene and acrylic monomers, have been used in combination with polyolefin-based yarns. Other additives with similar properties have been developed for introducing amino groups into the polyolefin polymer during the polymerization phase. To achieve dyeability of polyolefin-based yarns with dispersed dyes, polyester additives and polar copolymers were used. The dyeing of polyolefin-based yarns with ligand-forming dyes is made possible by the addition of a nickel compound. For standard polyolefin polymers, hydrocarbon-soluble dyes with long alkyl chains have also been proposed. A dyed polypropylene polymer is proposed through the use of special dendrimers and hyperbranched polymers. Plasma treatment has been proposed on a laboratory scale for introducing reactive groups into the surface of the yarn.

Although previous developments have had limited success, all of the above methods suffer from an increase in cost, which reduces the competitiveness of the polymer, a decrease in the mechanical properties of the obtained yarn, and the formability of the yarns and can adversely affect the thermal stability of the yarn. The stain resistance properties of such a yarn and the color fastness of the dyed fibers are also unacceptable or are below the required values.

Therefore, there remains a need for improved polyolefin-based yarns and fibers for use in carpets, textiles, upholstery and other applications where the properties of polyolefin materials can be beneficial.

Summary of the invention

From the point of view of the above and other objectives, the invention provides a method for manufacturing yarns and fibers having a denier per filament (dpf) of from about 1 to about 30 dpf and improved mechanical properties. The method comprises mixing from about 55 to about 95% by weight of a polyolefin polymer and from about 5 to about 45% by weight of a fibril forming polymer to form a mixture of a polyolefin and fibril forming polymers. The hot melt extruder into which the mixture is fed is used to produce a substantially homogeneous molten mixture of the polyolefin and the fibril forming polymers. The molten mixture is then extruded through a die having a length to diameter ratio (L / D) of about 3 to about 30 at a shear rate of about 1000 to about 5000 reverse seconds to form a fiber having a polyolefin matrix and elongated in substantially discontinuous fibrils of the fibril forming polymer dispersed in the polyolefin matrix, whereby the outer surface of the fibers is substantially free of fibrils.

In another aspect, the invention relates to yarn having improved mechanical properties and increased dyeability. The yarn comprises from about 55 to about 95 wt.% The polyolefin continuous phase and from about 5 to about 45 wt.% The discontinuous phase of the fibrils dispersed in the polyolefin continuous phase, the fibrils obtained from the fibril forming polymer selected from the group consisting of polyamide polymers and polymers based on polyesters. The polyolefin continuous phase is substantially free of fibrils on its outer surface, the yarn is dyed by reactive dyes, such as acidic or cationic dyes, and the yarn exhibits permanent deformation at about 25 ° C lower than about 3%.

In another aspect, the invention relates to a method for improving the mechanical properties of yarns made from synthetic fibers at a temperature higher than room temperature, including:

supplying a mixture containing from about 55 to about 95 wt.% polyolefin polymer, from about 5 to about 45 wt.% forming fibrils of the polymer and from about 0 to about 20 wt.% polyolefin compatibility agent selected from the group consisting of maleated polypropylene maleated copolymer of ethylene / propylene, maleated copolymer of styrene / butadiene / styrene, maleated copolymer of styrene / ethylene / butadiene / styrene, maleated copolymer of ethylene / propylene / ienovogo monomer (EPDM) rubber and maleatirovannogo of ethylene / propylene (EPR), a hot melt extruder to form a substantially homogenous molten mixture of polyolefin, fibril forming polymer and compatibilizer;

extruding the molten mixture through a die at a shear rate of about 1000 to about 5000 reverse seconds, the die having a length to diameter ratio (L / D) selected between 1 and 3 to achieve enhanced dyeability of the fibers with cationic dyes and an L / D ratio selected between 3 and 30 to achieve enhanced dyeability of the fibers with dyes in solution, to obtain a fiber having a polyolefin matrix and elongated, substantially discontinuous fibrils of the fibril forming polymer, dispersed in the polyolefin matrix.

The present invention is an improvement on the invention described in related US Pat. Nos. 5,587,118, 5,597,650, 5,620,797 and 5,811,040 to Mallonee, which provide a process for blending immiscible polymers to provide improved yarn for the front of carpets. It is shown that the filaments made according to the invention have a substantially continuous polyolefin phase and a substantially discontinuous fibril phase dispersed in the polyolefin phase. The discontinuous phase of the fibrils gives the polyolefin-based carpet fiber properties such as polyamide and / or polyester in terms of elasticity and color fastness, but without the obvious characteristic drawbacks of the fibril forming material. That is, the yarn exhibits excellent anti-pollution properties of the polyolefin and its favorable properties to delay combustion and antistatic properties, but does not exhibit the disadvantages of conventional polyolefin fibers. Fiber is also less costly to produce than many polyamide and polyester filaments, since polypropylene is currently up to about 60% cheaper per pound than polyamide and about 40% cheaper than polyester.

In addition to the above properties, the yarn of the invention includes a polyolefin matrix and polyester fibrils have a matte finish, thereby reducing the need to add fillers, such as titanium dioxide, to reduce the gloss of yarn, as is required for conventional polyamide fibers for making carpets.

A brief description of the graphic material

Additional advantages of the invention will become apparent by reference to the detailed description when considered in conjunction with the figures, where reference numerals indicate the same elements in several forms and where:

Figure 1 is an illustration, but on a different scale, of a preferred configuration of a bore of a die for producing synthetic fibers of the invention;

FIGS. 2 and 3 are cross-sectional illustrations, but on a different scale, having the shape of three protrusions or the delta shape of synthetic fibers made according to the invention;

Figure 4 is a graphical comparison of the tensile strength for fibers made from individual polymers and blends of polymers;

5 is a micrograph of a polyolefin fiber after chemical etching obtained by a method in which the L / D ratio of the die used to make the fiber is less than 3;

6 is a micrograph of a polyolefin fiber after chemical etching obtained by a method in which the L / D ratio of the die used to make the fiber is 3;

7 is a micrograph of a polyolefin fiber after chemical etching obtained by a method in which the L / D ratio of the die used to make the fiber is 6;

Fig. 8 is a micrograph of a polyolefin fiber after chemical etching obtained by a method in which the L / D ratio of the die used to make the fiber is 15;

Fig. 9a is a discrete image of a fabric sample made from conventional polyester yarn after 2500 brushing cycles;

Fig. 9b is a discrete image of a fabric sample made from conventional polyester yarn after 10,000 processing cycles and

Figure 10 is a graphical comparison of the mechanical properties of the fibers made according to the invention (curves A and B) and pure polyolefin fibers (curves C and D) with heat treatment (curves B and D) and without heat treatment (curves A and C).

Detailed Description of Preferred Embodiments

Synthetic fibers and yarns made according to the invention using a mixture of immiscible polymers preferably have a denier per filament (dpf) of from about 1 to about 30. Since the polyolefin and the fibril forming polymer that is not miscible with the polyolefin are melt blended and extruded through capillary holes of the die in the form of a molten mixture, each of the obtained filaments contains essentially the same amount of polyolefin and the fibril forming polymer as the molten Separated mixture.

The resulting fibers are characterized by a continuous phase polyolefin matrix having substantially linearly discontinuous elongated fibrils dispersed therein throughout the matrix. An important feature of the polyolefin-based synthetic yarn of the present invention is that it has an elasticity similar to that of a polyamide yarn such as nylon 6 and nylon 66, but is resistant to contamination of a polyolefin yarn such as polypropylene. In addition, the synthetic yarn of the present invention has significantly higher dyeability, fire resistance and mechanical strength at temperatures higher than room temperature than a pure or starting polyolefin polymer. Finally, the synthetic yarn of the present invention is resistant to the formation of static electric charges common to polyamide-based carpet yarn.

To provide a suitable mixture of immiscible polymers for the manufacture of synthetic fibers and yarn, a mixture containing from about 55% to about 95% by weight of the polyolefin is mixed with the fibril forming polymer in an amount of from about 5 to about 45% by weight. Preferably, the mixture of the polyolefin and the fibril forming polymer used to make the fibers and yarns of the present invention contains from about 60 to about 95 wt.%, More preferably from about 70 to about 85 wt.% And, most preferably, 75 wt. % polyolefin. The fibril forming polymer is preferably present in the mixture in an amount of from about 5 to about 40 wt.%, More preferably from about 15 to about 30 wt.%, And most preferably 25 wt.% Of the fibril forming polymer.

Polyolefins that can be used to make yarn and fibers of the invention include, but are not limited to, polyethylene, polypropylene, both homopolymer and copolymers, poly- (1-butene), poly- (3-methyl-1-butene) , poly- (4-methyl-1-pentene) and the like, as well as combinations or mixtures of two or more of the above. Of the above polyolefin polymers, polypropylene homopolymer is particularly preferred. Bulk polypropylene suitable for the yarn of the invention is available from, but not limited to, Shell Chemical Company of Houston, Texas, under the trademarks NRDS-126-3, 5E40 and 5E70, Basell Polyolefins Company N.V. of Brussels, Belgium, under the trademarks MOPLEN X69S, ADSTIF 855 ADXP, X500251, ADFLEX X102S and Aristech Chemical Company of Pittsburgh, PA, under the trademarks D-115-F and D-080-A.

The fibril forming polymer mixed with the polyolefin for the production of filaments can be selected from the group consisting of polyamide and / or polyester. Polyamide polymers that can be used include the condensation product of dibasic acid and diamine, such as adipic acid and hexamethylenediamine (nylon 66), and reaction products of the addition of monomers containing both an acid group and an amino group in the molecule, such as the product of the polymerization of ε-caprolactam with the formation of polycaproamide (nylon 6). Higher analogs or mixtures of nylon 6 and 66 may also be used. Of the above, nylon 6 is the most preferred polyamide for use in the manufacture of the yarn of the front side of the carpets of the present invention. Suitable sources of polyamide polymers include, but are not limited to, nylon 6 polymers available from AQUAFIL S.P.A. of Arco, Italy, under the trademark AQ2700 and from BASF Corporation of Asheville, N.C. under the trademark Type 403. Other sources of polyamide polymer may also be suitable.

Polyester polymers that can be used to make the yarn of the invention include, but are not limited to, polycondensation products of dicarboxylic acids or their anhydrides with dihydric alcohols and mixtures of polycondensation products. Dicarboxylic acids and their anhydrides that can interact with dihydric alcohols include saturated or unsaturated fatty acids and their anhydrides such as maleic, fumaric, phthalic and adipic acids and anhydrides. A particularly preferred dicarboxylic acid or its anhydride is phthalic acid or its anhydride.

Dihydric alcohols that are reacted with dicarboxylic acids or their anhydrides to produce polyester polymers include, but are not limited to, alkylene glycols having from about 2 to about 10 carbon atoms. Preferred dihydric alcohols include ethylene glycol, propylene glycols, diethylene glycol and dipropylene glycol. Particularly preferred polycondensation products of dicarboxylic acids or their anhydrides and dihydric alcohols include polyethylene terephthalate, polybutylene terephthalate and polytrimethylene terephthalate.

A suitable source of the polyester polymer is a polyethylene terephthalate polymer, available from Wellman Corporation, of Johnsonville, C, C. under the trademark PERMACLEAR PET. Other sources of polyester polymer that can be used include a polybutylene terephthalate polymer available from Montefibre of Milano, Italy, under the trademark TQ9 / 04 / N and from BASF Corporation of Portsmouth, Virginia under the trademark ULTRADUR B 4500. Another source is polytrimethylene terephthalate, available from Du Pont Company of Wilmington, Delaware under the trademark 3GT or SONORA; and polytrimethylene terephthalate, available from Shell Chemical Company under the trademark CORTERRA, as well as other suitable sources.

In addition to the polyolefin and the fibril forming polymers, the mixture may contain from about 0 wt.% To 20 wt.% Of the polyolefin compatibility agent. The polyolefin compatibility agents that can be used can be selected from several polyolefin polymers reacted with acids or anhydrides, including fumaric acid, acrylic acid or methacrylic acid, as well as maleated polyolefins. Examples of maleated polyolefins include maleated polypropylene, maleated copolymer of ethylene-propylene, maleated copolymer of styrene-butadiene-styrene, maleated copolymer of styrene-ethylene-butadiene-styrene, maleated ethylene-propylene rubber (EPR), ethylene-diene maleate and mixtures thereof. Sources of maleated polyolefins include, but are not limited to, POLYBOND 3200, available from Uniroyal Chemicals of Middleburg, Connecticut, and EPOLENE E-43, available from Eastman Chemical Company of Kingsport, Tennessee.

The synthetic yarn of the invention may also contain any one or more additives selected from flame retardants, dyes, pigments, antioxidants, fillers, antistatic agents, substances for improving the technological properties of the melt, UV stabilizers, thermal stabilizers, plasticizers and the like. A particular advantage of the invention is a synergistic retardation of the ignition of yarn and fibers. Even if the filaments of yarn may contain a non-halogenated fibril-forming polymer and do not contain flame retardants, the yarns of the invention can exhibit from about 45 to about 75% an increase in retardation of fire relative to pure polyolefin yarn. To further increase the retardation of the ignition of the synthetic yarn of the invention, the fibril forming polymer may be halogenated. For example, one or both of the dicarboxylic acid or its anhydride and dihydric alcohols used to make the polyester polymer may be halogenated. Halogens that may be used include chlorine, bromine, and fluorine. If desired, halogenated polyester compounds derived from halogenated acids or alcohols can also be mixed with other well-known halogenated and non-halogenated flame retardants to further increase retardation of the ignition of the fibers and yarns of the invention.

If desired, the polyolefin / fibril forming polymer blend of the invention may also contain other flame retardants. Flame retardants suitable for use with one or both of the components of the mixture include, but are not limited to, brominated polystyrene, hexabromocyclododecane, decabromodiphenyl oxide, ethylene bis (tetrabromophthalimide), ethylene bis (dibromonorboro diphenyl diphenyl dibenethoxy dibenethoxy dibenethoxy dibenethenyl dibenodoxybenzene diphenyl dibenodoxybenzene diphenyl dibenodoxybenzene dibenodibenoxide , bis (tribromophthalic anhydride), tetrabromobisphenol-A, bis- (2-hydroxyethyl ether), tetrabromobisphenol-A, bis- (2,3-dibr propyl ether), dibromneopentyl glycol, tetradecabromodiphenoxybenzene, trihydrated alumina, antimony oxide, sodium antimonate, zinc borate, tetrabromobisphenol-A diacrylate ester and the like, and mixtures thereof.

A preferred fire retardant system typically comprises a halogenated organic compound and a fire retardant synergist such as antimony oxide. The total amount of flame retardant in the yarn can be from about 5 to about 15 wt.% The total weight of the fibers. At about 10 wt.% Flame retardant, an approximately 50% increase in ignition retardation is often observed, as determined by the ignition retardation test with the emitter panel.

Thermal stabilizers useful with the components used to make the fibers of the invention include, but are not limited to, calcium powders, calcium stearate, phenols and hindered phenols, zinc oxide, aryl esters, hydroxybenzophenone, hydroxybenzotriazole and the like.

Additives, antioxidants may be selected from alkylated phenols and bisphenols, alkilidenbisfenolov, alkilidentrisfenolov, alkilidenpolifenolov, thiophenols, ditiobisfenolov, ditiotrisfenolov, tiopolialkilirovannyh phenols, condensation products of phenols, amines, dilauryl thiodipropionate, distearyl thiodipropionate, dimiristiltiodipropionata, ditridetsiltiodipropionata tetrakis (β-lauriltiopropionata) pentaerythritol, n -benzoquinone, 2,5-di-tert-butylhydroquinone and the like.

Antibacterial and dust mite additives may also be used. Among them, inorganic glassy additives or zeolite-based additives can be selected. Other types of antibacterial and dust mite additives may also be used.

The polyolefin, the fibril forming polymer, and optional additives can be combined in various ways, however, it is preferable to dry mix the components before feeding the mixture to the extruder. Alternatively, each of the polyolefin, fibril-forming polymer components, and optional ingredients can be introduced directly into the extruder in any order, provided that the residence time in the extruder is sufficient to ensure substantially homogeneous mixing of the components. It should be understood that a pre-mixed, essentially homogeneous mixture of the polyolefin and the fibril forming polymer can also be introduced into the extruder.

As for the fibril-forming polyester polymer, after combining, the mixture of the polyolefin and the polyester is melt-blended and extruded under pressure to obtain a substantially homogeneous mixture of the two components. A pressure of from about 700 to about 2000 psi. an inch (from about 4.8 MPa to about 13.8 MPa) is preferably used to obtain a homogeneous mixture of components before extrusion. The molten mixture is extruded from the extruder die at a temperature in the range of 240 ° C. to about 300 ° C. through the die holes. The extruder temperature used is a function of the viscosity of the fibril forming polymer in the mixture. When the fibril forming polymer has a higher viscosity, higher extrusion temperatures must be used. For example, when using nylon 6, the extrusion temperature is preferably in the range of from about 250 ° C to about 290 ° C. When using polyethylene terephthalate, the extrusion temperature is preferably in the range of from about 260 ° C to about 300 ° C.

The following figures may be used to illustrate other aspects of the invention. Figure 1 illustrates a capillary hole (10) for a die used to make filaments for the manufacture of fibers and yarn of this invention. The capillary hole is preferably a capillary configuration with three protrusions. The capillary hole (10) has protrusions (12) of substantially equal length, so that the molten mixture flows through the capillary hole (10) into the protrusions (12), thereby increasing the bias rate on the molten mixture and causing the filament to solidify essentially usually in a configuration with a cross section with three protrusions (14), as shown in FIG. 2, or a configuration with a cross section in the form of a delta (16), as shown in FIG. 3. In FIGS. 2 and 3, the polyolefin (18) forms a volume of a filament with elongated, longitudinally oriented fibrils (20) made by a fibril forming polymer dispersed in the filament, and usually concentrated towards the center of the filament.

The shear rate of the molten mixture during extrusion is another important factor in the practice of the present invention to achieve optimal results. Shear rates in the range of about 1000 to about 5000 reverse seconds are preferred. Especially preferred is a shear rate in the range of from about 2000 to about 4000 reverse seconds, with a shear rate of from about 2500 to about 3800 reverse seconds being particularly preferred. By selecting a plurality of capillary holes of suitable size, having a shape with three protrusions, the desired shear rate for extrusion of the mixture can be achieved.

A particularly important parameter to take into account is the ratio of the height or length (L) of the capillary hole to the average hydraulic diameter (D) of the capillary 10 through which the molten mixture is forced to pass. The preferred L / D ratio is in the range of about 3 to about 30, depending on the viscosity of the melt of the polyolefin and the fibril forming polymer and on the shear rate in the hole of the capillary 10. To minimize or substantially eliminate the presence of fibrils on the outer surface, preferably use the ratio in the range of from about 6 to about 10. Reactive dyeing of fibers using acidic or cationic dyes can be enhanced by using a ratio of L / D of about 1 to about 3. Accordingly, a suitably selected L / D ratio increases the concentration of the fibril forming polymer within the polyolefin matrix and reduces the average diameter of the fibrils.

Without claiming to be a specific theory, it is believed that the properties of the fibers and yarns of the invention are caused, at least in part, by the formation of in-situ elongated, substantially discontinuous fibrils in the continuous polyolefin phase. It is believed that in situ formation of fibrils is promoted by immiscibility of the average diameter of fibrils.

Without claiming to be a specific theory, it is believed that the properties of the fibers and yarns of the invention are caused, at least in part, by the formation of in-situ elongated, substantially discontinuous fibrils in the continuous polyolefin phase. It is believed that in situ formation of fibrils is promoted by the immiscibility of the mixture components with each other and the shear force acting on the molten mixture when it is extruded through the capillary holes 10 of the die. The presence of a polyolefin compatibility agent helps to increase the formability and mechanical strength of the boundary between the polyolefin matrix and the immiscible polymer.

During extrusion, the polymer-formed fibrils are usually concentrated with a longitudinal, line-oriented orientation towards the center of the capillary holes 10 of the die, where the bias force is the smallest. As a result, elongated fibrils are dispersed in a continuous polyolefin phase, which is concentrated near the walls of the holes of the die capillaries, where the bias force is greatest. Polyamide and / or polyester fibrils and / or fibrils of other polymers not miscible with the polyolefin, which are formed by shear forces associated with the passage of the material through the openings of the capillaries 10, have a diameter in the range from a fraction of a micron to several microns and a length of several tens of microns, while related to the cross section, the total length of each side of the fibril containing filaments with a shape having three protrusions, or a delta shape, can be from about 1 to about 3 millimeters. Fibrils typically have an average diameter of about 0.1 to about 5 microns and an average length of about 100 to about 1000 microns, depending on the ratio of viscosity and molding parameters.

Although the phenomenon is not fully understood, the polyolefin turns into a continuous phase, providing a matrix encapsulating polymer fibrils. Polymer fibrils provide hardening of the polyolefin matrix, similar to the hardening provided by fiberglass in a thermoplastic or thermosetting resin. Accordingly, polymer fibrils, which are more flexible than the polyolefin, increase the elasticity of yarn and fibers compared to conventional polyolefin fibers and yarns, thereby providing excellent material for the manufacture of BCF, CF yarn used as the yarn for the front side of carpets , POY, FDY or LDY yarn used as textile yarn, upholstery yarn or staple yarn.

It is believed that another factor contributing to the formation of fibrils in the center of the filament is the difference in melt viscosity between the phases of the polyolefin and the fibril forming polymer. Typically, a lower melt viscosity of the polyolefin can cause the polyolefin to flow much more easily through the hole of the capillary 10 at the walls of the hole where the displacement rate is highest, while the more viscous, fibril forming polymer concentrates on the area of the hole of the capillary 10 away from the walls. For example, at a shear rate of 3800 reverse seconds, polypropylene has a melt viscosity of 240 poises at 280 ° C. at the capillary wall. The melt viscosity at the same temperature and shear rate for a polyester having an intrinsic viscosity of 0.64 is 2,600 poises and 7,800 poises for a polyester having an intrinsic viscosity of 0.81 at 280 ° C. Accordingly, the ratio of the melt viscosity of the polyester polymer to the melt viscosity of the polyolefin is preferably in the range of about 10: 1 to about 40: 1 to obtain filaments of the invention containing polyester fibrils in a polyolefin matrix.

At a shear rate of 2500 reverse seconds, polypropylene has a melt viscosity of 330 poise at 260 ° C. at the capillary wall. The melt viscosity for the same temperature and shear rate for nylon 6 having a relative viscosity of 2.4 is 700 poise and 1160 poise for nylon 6 having a relative viscosity of 2.7. Accordingly, the ratio of the melt viscosity of the polyamide polymer to the melt viscosity of the polyolefin is preferably in the range of from about 2: 1 to about 3: 1 to obtain filaments containing polyamide fibrils in the polyolefin matrix.

After molding, the filaments are pulled one or more times, preferably three times, and then textured with either a hot air nozzle or a steam ejector. Molding, drawing and texturing can be carried out in either a one-step or a two-step way, depending on the type of end product required, such as BCF yarn (bulk continuous yarn used to make carpets), CF (continuous yarn used to make fabric and upholstery) used as yarn for the front of carpets, yarn POY (pre-oriented yarn used to obtain a fully oriented yarn), FDY (fully oriented yarn), we use as yarn for textiles, yarn for upholstery or staple yarn, and with parameters set depending on the particular yarn used for producing dyed yarn for the front of carpets, the components that combine to produce the yarn of the invention may each contain pigments or chemical dyes, or finished yarns or fibers can be dyed. Suitable inorganic pigments include, but are not limited to, cadmium mercury, cadmium mercury orange, cadmium sulfide yellow, cadmium sulfoselenide, titanium dioxide, titanium yellow, titanium green, titanium blue, cobalt aluminate, manganese blue, manganese violet, ultramarine red, ultramarine red, ultramarine red, ultramarine red ultramarine violet and the like. Organic pigments include, but are not limited to, permanent red 2B, perylene red, quinacridone red, diazo orange, iazo yellow, isoindolinone, hansa yellow, phthalocyanine green, phthalocyanine blue, quinacridone purple, dopamine purple and the like.

Chemical dyes include, but are not limited to, mono- and disulfonated acid dyes, as well as triphenylmethane, pyrazolone, azine, quinoline dyes and nitro dyes. In use, pigment dyes can be pre-dispersed in a polyolefin bath prior to extrusion of the polyolefin and the fibril forming polymer or can be introduced after the extrusion process using a side extruder system.

Since filaments of pure polyolefin cannot usually be dyed with chemical acid or cationic dyes, pigment dyes are usually used during the manufacture of yarn, thus obtaining a polyolefin dyed in a manner known as “dyeing in solution”. Dyeing in solution results in a persistent color that is very resistant to fouling or fading due to UV rays.

In contrast to the conventional polyolefin fibers and yarns, the fibers and yarns of the invention can be dyed with disperse dyes in addition to using pigment dyes during manufacture, and after dyeing the fibers and yarns of the invention, it has been found to exhibit pollution resistance properties similar to pure polyolefin fibers and yarns.

In addition, when the fibril-forming polymer used with the polyolefin for producing filaments is polyamide, the yarn of the invention has improved acid dyeability, color fastness and pollution resistance, and also has improved cationic dye coloring, color fastness and pollution resistance. However, it is preferable to use a mixture of acid dye and dispersed dye for dyeing filaments. The dye mixture may contain from 0 to about 50 percent dispersed dye and from about 50 to about 100 percent acid dye. A particularly preferred colorant is a mixture of about 50 wt.% Acid dye and about 50 wt.% Dispersed dye. When the polymer used is a polyester, disperse colorant is preferably used. Dispersed dyes are usually used with a carrier fluid that is compatible with a particular dye, suitable carrier fluids are known to those skilled in the art. The amount of dye in the carrier fluid used for dyeing filaments can be from about 0.15 to about 0.7 wt.% Of the dye and carrier fluid, preferably from about 0.2 to about 0.5 wt.% Of the dye and carrier fluid.

For dyeing filaments, the single filaments are preferably rinsed first with hot water, usually containing about 0.5% by weight of a base such as NaOH, KOH or NH ₃ OH. The temperature of the hot wash water is from about 60 ° C to about 80 ° C, and the water should be hot enough to remove any residual finishing oils that may be on the filaments.

After washing, the filaments are preferably dyed in a dye bath at a temperature of from about 90 ° C to about 100 ° C for at least 15 minutes or longer. A fiber or yarn made from a polyolefin / polyester blend may be dyed using from about 0.2 to about 0.6 wt.% Dispersible dye at the same temperature and pressure or at a temperature of from about 115 ° C. to about 120 ° C, while maintaining the dye at low pressure.

When a fibril-forming polyamide base polymer or any other polymer containing reactive groups like the —NH ₂ amino group or —COOH group is used, the polyolefin base synthetic yarn of the invention can be dyed with acid or cationic reactive dyes with or without dispersed dyes using high pressure systems with pressures of about 1 to about 5 bar. In this case, you can get a very stable color, resistant to the action of washing, shampoo, UV light and ozone, in the case of fibers and yarns, exposed to temperatures up to approximately 100 ° C.

Various features and aspects of the invention will now be illustrated with reference to the following non-limiting examples.

Example 1

Two types of polypropylene polymer were evaluated in a dry mixture containing 15 wt.% Nylon 6 granules having a relative viscosity of 2.7 (type BS-700 from BASF Corporation) and 85 wt.% Polypropylene granules having a melt index of 20 (5-1466 of Union Carbide Corporation), and polypropylene granules having a melt index of 9 (5E40 from Union Carbide Corporation). Granules 5E40 had a crystallinity coefficient of 50-55%. The dry mixture was fed directly from the feed hopper to a 1 ° inch hot melt extruder, where a homogeneous molten mixture was obtained. The 85 wt.% Polypropylene portion consisted of 4 wt.% Beige dye concentrate (SCC 13524 from Standridge Color Corporation) and 2 wt.% Grafted maleic anhydride (POLYBOND 3200 from Uniroyal Chemical Company). The molten mixture was then pumped through a block of screens to remove any particles greater than 20 microns. The mixture passed through a sieve was squeezed out through a die having 67 capillary shaped holes with three protrusions to obtain filaments. Each capillary with three protrusions had a protrusion length of 0.0205 inches and a protrusion width of 0.008 inches. The extrusion rate was 0.25 pounds per hour per capillary orifice at 260 ° C., resulting in a displacement rate of 3245 reverse seconds. The yarn for carpets was spun from the filaments thus formed in a single-stage manner. Extraction molding was carried out using nylon 6 extrusion conditions at 1200 m / min. The filaments having a shape with three protrusions were spun at 3900 denier for 67 filaments at a temperature of 256 ° C. The yarn was drawn three times at 125 ° C and textured through a nozzle with hot air at 150 ° C. The stretch yielded a textured yarn having 1150 denier for 67 filaments. The relaxation ratio was 0.71: 1 and the target denier after stretching was 1150 per 67 filaments. The physical properties of yarns made by this method and comparative yarns are given in the following table 1.

Table 1 No.
experience Description Denier Tensile strength Elongation at break (%) Mass (%) (125 ° C) g / denier g / dtex one PP control (5E40) 1152 2.7 2.40 122 21 2 PP control (5-1466) 1148 2,5 2.25 115 17 3 85 wt.% PP (5-1466)
15 wt.% RA (BS-700) 1147 2,5 2.25 64 16 four 85 wt.% PP (5E40)
15 wt.% RA (BS-700) 1145 2,8 2,50 74 eighteen 5 RA Control (BS-700) 1149 3.2 2.90 88 17

As shown in the above examples, mixtures of polypropylene and nylon showed substantially weaker elongation than pure polymers of either polypropylene or nylon, while other properties of the fibers were essentially the same. A fiber made with nylon 6 and polypropylene having a melt index of 9 showed the highest tensile strength and elongation at break of mixed polymers.

Example 2

The yarns for the front side of the carpets were obtained from fibers formed in Example 1. To obtain yarn suitable for the front side of the carpets, the polyolefin / nylon (PP / PA) blend yarns were twisted and heat-shrinked from 1150 denier. The twisting of the filaments was 4.25 × 4.25 tpi (number of torsions per inch) and the yarn was heat-shrinked on a chamber to impart SUPERBA crimp fiber at a tunnel temperature of 132 ° C for a polypropylene control sample and 121 ° C for a nylon control sample.

After twisting and heat shrinkage, the yarn of the invention was sewn on a wide loom in a split pile of 28 ounces, having 24 seams and a pile height of 21/32 inches. Sexual coverage was evaluated after 20,000 drives.

table 2 Experience number Description Flooring assessment one PP control (5E40) 2.00 2 PP control (5-1466) 1.75 3 85 wt.% PP (5-1466)
15 wt.% RA (BS-700) 2.25 four 85 wt.% PP (5E40)
15 wt.% RA (BS-700) 3.25 5 RA Control (BS-700) 2.75

As shown by the above comparisons, a carpet made from PP / PA fibers rated Carpet Research Institute (CRI) as 29–62% better than pure polypropylene yarn, and in Test 4 it was rated 18 % better than pure nylon yarn.

Example 3

Molding tests were carried out using several types of polypropylene (PP), namely UC 1465 and UC 5E40 from Union Carbide and XA16 from Amoco. The selected polypropylene and nylon 6 with a relative viscosity of 2.7 (AQ 27000 from Aquafil) were separately fed from two loading crates into the extruder of the molding equipment to obtain BCF yarn for the front of the carpets. A polypropylene-based compatibility agent containing maleic anhydride pre-crosslinked with a polypropylene molecule (PP-AM) was introduced via a third loading box into the extrusion system. During testing, a standard auger with a Barmag homogenization zone was used.

A die with 64 openings having an L / D 3 ratio was used with a displacement speed at the capillary of approximately 2900 reverse seconds. The polymer blend is shown in Table 3. Prior to feeding to the extruder, both nylon 6 (PA6) and PP-AM were dried. The moisture content in the PA6 was less than about 500 parts per million ^(-1), namely 300 ppm.

The extrusion was carried out in a screw zone with homogenizing a 2 _^1/2 inches. The molten mixture was pumped into a block sieve to remove any particles larger than 30 microns. The sieved mixture was extruded through a 64-hole die with three protrusions. The yarn was then stretched with an elongation factor of 4 and textured with hot air at 130 ° C. The treatment was carried out at a drawing speed of 2200 m / min. The final yarn number was 1330 dtex. The properties of the yarn are given in the following table 3 and the tensile strength is illustrated in figure 4.

Table 3 Polymer type PP (wt.%) PA6 (wt.%) PP-AM (wt.%) Tensile Strength (g / dtex) Elongation at break (%) Mass (air, 130 ° C) AQ2700 0 one hundred 0 2.63 66 - PP A (UC 1465) 100.0 0 0 1.55 115 12.1 PP A (UC 1465) 82.3 fifteen 2,8 1.80 65 8.9 PP B (UC 5E40) 100.0 0 0 2.15 66 - PP B (UC 5E40) 83.0 fifteen 2 2,35 55 PP B (UC 5E40) 84.0 fifteen 1,0 2,36 47 -

and PP and various numbers of yarn. The results are shown in the following table 4.

Table 4 Experience number Yarn Number (den.tex) PP (wt.%) PA6 (wt.%) PP-AM (wt.%) Tensile Strength (g / dtex) Elongation at break (%) Mass (air, 130 ° C) one 1330 one hundred 0 0 2.20 96 13.1 2 1330 83 fifteen 2 2.45 60 9.3 3 1330 one hundred 0 0 2.20 96 13.1 four 1330 83 fifteen 2 2.45 60 9.3 5 1020 85 fifteen 2 2,35 74 10.1 6 1729 83 fifteen 2 2,35 57 10,2 7 1330 78 twenty 2 2,35 58 9.6 8 1330 73 25 2 2,30 56 9.5 9 1330 63 35 2 2.20 61 9.2

The above results showed that the physical properties of the yarn made according to this invention do not change significantly with a change in the concentration of the components. The mixtures shown in table 4 show the applicability of the yarn made according to the present invention within a wide range of compositions.

Example 5

To evaluate the effectiveness of synthetic yarn, 1330 / 64CH2 yarn with air weaving was made as yarn for the front side of carpets. The yarn was stitched on a machine to produce 1/10 inch piercing carpets with a pile height of 5 mm and two different designs to achieve a pile density of 450 and 550 g / m ² . The carpet was stained in a bath using dispersed dyes (Dystar dispersed dyes) and tested by the method of castor stool and the Vetterman drum strength test method. The test by the Vetterman drum strength test method was carried out by simulating a wear test according to ASTM D5417. The degree of wear exhibited by the samples was determined by visual assessment of photographic wear standards from The Carpet and Rug Institute (CRI Reference Scale, available from CRI, PO Box 2048, Dalton, Ga., USA). Each of the common types of carpet designs has a corresponding set of photographic examples of unworn and worn patterns. Levels of wear ranged from 5 to 1, where 5 represents the absence of visible wear and 1 represents significant wear.

The test results of the castor chair and the Vetterman drum test were determined on carpets 450 and 550 g / m ² made with the yarn obtained according to this invention, compared with a carpet made using yarn from 100 wt.% Nylon 6 (RA) and yarn from 100 wt.% PP having the same characteristics. The results are presented in table 5 as a function of carpet density and polymer type.

Table 5 Polymer 100 wt.% RA 100 wt.% PP 85 wt.% PP
15 wt.% RA Carpet pile density (g / m ² ) 450 550 450 550 450 550 Vetterman Wear Level 5000 2,5 3 2 2 2,5 2,5 Vetterman Wear Level 22000 2,5 2,5 1,5 2 2 2 Castor chair wear level final 1.88 1.88 1.88 1.88 1.88 1.88

As shown by the above comparisons, the yarn made according to the present invention exhibits a wear behavior that is better than the wear behavior of a carpet from pure PP yarn and is comparable to the wear behavior of a carpet from pure nylon 6.

Example 6

The molding of a mixture containing 20 wt.% Nylon 6 and 3 wt.% Compatibility agent was carried out using various dies, characterized by L / D ratios of 2 to 15. The dies were made in various sizes to maintain a constant shear rate of approximately 2900 reverse seconds. The spinning properties of BCF 1330 dtex / 64 yarn were similar to those of Example 3.

After molding, a metallographic analysis was performed to evaluate the distribution of nylon 6 in the filaments. The surface of the filaments was analyzed using a Jeol scanning electron microscope (SEM) in the laboratories of the University of Trento in Italy before and after immersion in acetic acid to remove nylon 6 on the outer surface of the yarn. Microphotographs indicated by FIG. 5-8 show the amount of nylon 6 present on the outer surface of the filaments and available for general contamination or contamination in the form of dark areas or holes where nylon 6 was dissolved with acid from the surface of the filaments for each of the used L / D ratios.

The results of the analysis carried out on BCF yarn obtained respectively using L / D ratios of 2, 3, 6, 15 showed that a significant amount of nylon 6 polymer was present on the outer surface of the filaments for an L / D ratio of less than 3. When L / D 3 or higher, the surface of the filaments is substantially devoid of nylon 6.

Example 7

The molding of the mixture was carried out in accordance with example 3, but the yarn had a delta cross-sectional shape, and not a cross-section with three protrusions. A polypropylene-based dyeing bath was used to prepare a dyed yarn solution. Concentrates of both beige and black dye were used. The mixture had the following composition: 72 wt.% Polypropylene (PP), 20 wt.% Nylon 6 (PA6), 6 wt.% Polypropylene with grafted maleic anhydride (PP-AM), 2 wt.% Dye concentrate. BCF yarn was extruded by molding through a die with holes with a cross section of a delta shape. The shear rate inside the multi-channel extruder was 2900 reverse seconds and the L / D ratio of the multi-channel extruder was 3. The molding-stretching speed was 2500 m / min. Hot air texturing was performed at 130 ° C. The degree of extraction was 4.5. After molding, the yarn obtained was numbered 650 dtex with 30 filaments. The yarn had a tensile strength of 3.35 g / dtex (3.7 g / denier) with an elongation at break of 45% and an increase in tensile strength of 15% compared with 100 wt.% PP.

The yarn was dyed using an Ahiba machine with disperse dye at 95 ° C for 30 minutes. Then, color fastness was determined after washing. Washing was carried out for 30 minutes using an aqueous solution with commercial shampoo at pH 7. The temperature was recorded at which the color began to change. The results showed that only a slight color change occurred when washing at temperatures up to 85 ° C.

Example 8

The mixture was formed as described in Example 7 to obtain a yarn dyed in solution. Used concentrates of both beige and black dye. The mixture had the following composition: 72 wt.% PP, 20 wt.% PA6, 6 wt.% PP-AM, 2 wt.% Dye concentrate. BCF yarn was extruded through a die with openings having a delta cross section. The shear rate inside the die was 2900 reverse seconds and the L / D ratio of the die was 3. The spin-draw speed was 2500 m / min. Hot air texturing was performed at 130 ° C. The degree of extraction was 4.5. After molding, the resulting yarn had a 650 dtex yarn number with 30 filaments.

The yarn had a tensile strength of 3.05 g / dtex (3.4 g / denier) with an elongation at break of 45% and an increase in tensile strength of 15% compared with 100 wt.% PP.

The yarn was woven for use as upholstery, flooring, fabric for upholstery, fabrics for decoration, panels. Several fabrics with different densities were produced as a function of end use.

Received the characteristic of wear resistance of the fabric with a density of 11.6 threads / cm, a total density of 454 g / m ² ; the base content was 46.6% with a stored duck density of 53.3%. The abrasion test of the fabric was carried out using a nylon brush with a force of 0.8 kg / cm ² and the data were compared with the strength of a standard fabric based on complex polyester using the same density after the same type of test. The polyester fabric test was stopped after 2500 cycles and after 10000 cycles for the claimed fabric. The results are shown in FIG. 9a (polyester fabric after 2500 brush cycles) and FIG. 9b (fabric made with the fiber of Example 8 after 10,000 brush cycles).

Example 9

The claimed synthetic yarn was made using POY spinning equipment. A mixture of 83 wt.% PP, 15 wt.% PA6, 2 wt.% PP-AM was pre-mixed and passed into the extruder after drying to a moisture content below 300 ppm. Molding was carried out at three speeds (2000, 2500 and 3000 m / min). 100/24 POY yarn was obtained. The resulting mechanical properties of POY are presented in the table below. After molding, FDY was obtained. A draw coefficient of 1.374 was used using a spinning disk temperature of 60 ° C. The results are presented in table 6.

Table 6 POY forming speed 2000 m / min 2500 m / min 3000 m / min POY dtex 99.9 99.6 99.1 POY Tensile Strength - cN / dtex 1.22 1.33 1.49 Elongation at break POY-% 279.31 249.46 214.77 Extraction ratio 1.374 Fdy dtex 75.5 77.1 78.3 FDY Tensile Strength - cN / dtex 1.66 1,67 1.85 Elongation at break FDY-% 186.2 168.9 152.9 Extraction ratio 1,741 Fdy dtex 56 57.1 57.9 FDY Tensile Strength - cN / dtex 2.23 2.43 2.75 Elongation at break FDY-% 74.3 68.7 64.3

The effectiveness of the claimed synthetic yarn in terms of elasticity and mechanical properties as a function of temperature was characterized at high temperatures and compared with the efficiency of the same fiber obtained using 100 wt.% PP. The effects of heat treatment were also tested. The elasticity of the yarn was evaluated using laboratory tests giving the yarn a strain and evaluating its ability to return to its previous state after removing the load. The tests were carried out at room temperature and at high temperatures. In tests conducted using dynamic apparatus at the University of Trento, Department of Materials, a maximum strain of 16 mm was applied to the yarn at a frequency of 5 Hz. To test the yarn, a static load of 0.05 N / dtex was applied to a single filament. The effect of temperature was achieved by increasing the temperature during the test at a rate of 3 ° C / min. The results are presented in FIG. 10 for FDY yarn made at 3000 m / min. Curve (A) shows the behavior of the yarn according to this invention obtained with 83 wt.% PP, 15 wt.% PA, while curve (B) shows the behavior of the same yarn after heat treatment at 130 ° C for 5 min. For comparison, curve (C) shows the deformation of yarn from pure PP without heat treatment and with the same heat treatment at 125 ° C for 5 min (curve D).

Figure 10 shows that the yarn made according to the present invention (curve A), provided significantly higher shape retention at room temperature, compared with a yarn of 100 wt.% PP (curve C), which began, having an irreversible deformation at temperature above -20 ° C, i.e. higher than its glass transition temperature. At 25 ° C, the deformation of the declared yarn was below 3%, which indicated excellent elasticity, while yarn from 100 wt.% PP already reached 30% residual deformation.

Tests also showed significantly better mechanical properties of the yarn made according to the present invention, even at high temperature. In fact, the residual deformation of the yarn made according to the invention at 50 ° C is only about 10% and only 20% (curve B) if the heat treatment at 130 ° C was carried out for 5 minutes On the contrary, more than 60% residual deformation was observed for pure PP yarn (curve C), which exceeded 100% if the yarn was subjected to heat treatment (curve D).

Examples of the use of yarn according to the invention include, but are not limited to: underwear, outerwear, sportswear, silk for edges, socks, clothing, ropes, filters for the chemical industry.

After describing and illustrating preferred embodiments, the invention should be understood that various modifications, permutations, and replacements may be made by a person skilled in the art for this invention without departing from the spirit and scope of the proposed claims.

Claims (30)

1. A method of obtaining fibers and yarns having a denier value per filament, from about 1 to about 30 and improved mechanical properties, including mixing about 55 to about 95 wt.% a polyolefin polymer and about 5 to 45 wt.% a fibril forming polymer to form a mixture of a polyolefin and fibril forming polymer; introducing the mixture into the hot melt extruder to produce a substantially homogeneous molten mixture of polyolefin and fibril forming polymers; extruding the molten mixture through a die having a length to diameter ratio of from about 3 to about 30, with a shear rate of from about 1000 to about 5000 reverse seconds, to obtain a fiber having a polyolefin matrix and elongated, substantially discontinuous fibrils forming the fibrils of the polymer dispersed in polyolefin matrix, as a result of which the outer surface of the fibers is essentially free of fibrils. 2. The method of claim 1, wherein the fibril forming polymer is selected from the group consisting of polyamide polymers and polyester polymers. 3. The method according to claim 1, where the polyolefin polymer comprises polypropylene. 4. The method according to claim 1, where the mixture comprises from about 15 to about 30 wt.% Forming fibrils of the polymer. 5. The method according to claim 1, where the ratio of length to diameter of the die is from about 6 to about 10. 6. The method according to claim 1, where the mixture of polyolefin and fibril forming polymers comprises from about 0 to about 20 wt.% Polyolefin compatibility agent selected from the group consisting of maleated polypropylene, maleated copolymer of ethylene / propylene, maleated copolymer of styrene / butadiene / styrene, maleated copolymer of styrene / ethylene / butadiene / styrene, maleated copolymer of ethylene / propylene / diene monomer and maleated rubber made of ethylene / propylene. 7. The method according to claim 6, further comprising drying the polyolefin polymer, forming the polymer fibrils and the compatibility agent to obtain a mixture containing less than approximately 500 parts per million moisture. 8. The method according to claim 1, further comprising drying the polyolefin polymer and the fibril forming polymer to obtain a mixture containing less than about 500 parts per million moisture. 9. The method according to claim 1, further comprising dyeing the fibers with a disperse dye, a reactive dye, or a mixture of both to produce colored fibers. 10. The method according to claim 9, where the dyeing is carried out at a pressure of from about 1 to about 4 bar. 11. The method according to claim 9, where the dyeing is carried out at a pressure of from about 1.5 to about 2 bar. 12. The yarn made by the method according to claim 1, which has a shape selected from the group comprising polyolefin-based yarn, bulk continuous yarn used as yarn for the front side of carpets, pre-oriented yarn, fully oriented yarn used as yarn for textiles, upholstery yarn or staple yarn. 13. A method of improving the mechanical properties of yarns made of synthetic fibers at a temperature higher than room temperature, including supplying a mixture containing from about 55 to about 95 wt.% polyolefin polymer, from about 5 to about 45 wt.% forming fibrils of the polymer and from about 0 to about 20 wt.% polyolefin compatibility agent selected from the group consisting of maleated polypropylene maleated copolymer of ethylene / propylene, maleated copolymer of styrene / butadiene / styrene, maleated copolymer of styrene / ethylene / butadiene / styrene, maleated copolymer of ethylene / propylene / ienovogo maleatirovannogo monomer and rubber of ethylene / propylene, a hot melt extruder to form a substantially homogenous molten mixture of polyolefin, fibril forming polymer and compatibilizer; extruding the molten mixture through the die at a shear rate of about 1000 to about 5000 reverse seconds, the die having a length to diameter ratio selected between 1 and 3 to achieve enhanced dyeability of the fibers with cationic dyes, and a length to diameter ratio selected between 3 and 30 to achieve increased dyeability of the fibers with dyes in solution, to obtain a fiber having a polyolefin matrix and elongated, substantially discontinuous fibrils of the polymer forming the fibrils, d spergirovannogo in a polyolefin matrix. 14. The method of claim 13, wherein the fibril forming polymer is selected from the group consisting of polyamide polymers and polyester polymers. 15. The method according to item 13, where the polyolefin matrix includes polypropylene. 16. The method according to item 13, where the molten mixture comprises from about 15 to about 30 wt.% Forming fibrils of the polymer. 17. The method according to item 13, where the ratio of length to diameter of the die is from about 6 to about 10. 18. The method according to item 13, further comprising drying the polyolefin polymer, forming the polymer fibrils and the compatibility agent to obtain a mixture containing less than approximately 500 parts per million moisture. 19. The method according to item 13, further comprising dyeing the fibers with an acid dye, with the formation of colored fibers. 20. The method according to item 13, where forming the fibrils of the polymer has a tintable cationic dye. 21. The method according to claim 20, further comprising dyeing the fiber using a mixture of cationic dye and dispersed dye. 22. The method according to claim 19, where the dyeing is carried out at a pressure of from about 1 to about 4 bar. 23. The method according to item 21, where the dyeing is carried out at a pressure of from about 1 to about 4 bar. 24. The yarn made by the method according to item 13, which has a shape selected from the group comprising polyolefin-based yarn, bulk continuous yarn used as yarn for the front part of carpets, pre-oriented yarn, fully oriented yarn used as yarn for textiles, upholstery yarn or staple yarn. 25. Yarn having improved mechanical properties, comprising from about 55 to about 95 wt.% A polyolefin continuous phase and from about 5 to about 45 wt.% The discontinuous phase of the fibrils dispersed in the polyolefin continuous phase, the fibrils being formed from a fibril forming polymer, selected from the group consisting of polyamide polymers and complex polyester polymers, where the polyolefin continuous phase is essentially free of fibrils on its exposed surface and where the yarn is krashivaemoy and has an irreversible deformation at about 25 ° ^C less than about 3%. 26. The yarn of claim 25, wherein the polyolefin continuous phase comprises polypropylene. 27. The yarn of claim 26, wherein the fibrils include a polyester, polyamide or polyamide dyed with a cationic dye. 28. The yarn of claim 25, having improved dyeability with an acid dye, color fastness and resistance to pollution. 29. The yarn according to item 27, having improved dyeability with a cationic dye, color fastness and resistance to pollution. 30. The yarn of claim 25, comprising continuous continuous yarn used as yarn for the front of a carpet, pre-oriented yarn, fully oriented yarn used as a textile yarn, upholstery yarn, or staple yarn.

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