FR2799768A1 - METHOD FOR MANUFACTURING YARNS FOR TUFT ARTICLES - Google Patents

Abstract

The invention relates to a method for producing a thread with at least two twisted ends, with the twist being fixed. The ends used for constructing the thread are spun when molten and textured in a superheated steam atmosphere. The threads produced according to the method can be used to obtain tufted surfaces with an improved surface appearance after dyeing.

Description

Method of making yarns for tufted articles

The present invention relates to a method for producing yarns for producing articles intended to be tufted, and more particularly to solid color carpets dyed after the tufting operation.

Tufted articles are mainly used to cover large surfaces, floors or walls. The technique of tufting is one of the preferred techniques for the manufacture of large items because it is economical and easily industrializable. Many developments have been made to give the articles the desired aspects. There are for example "curly" carpets, "cut" carpets of greater or lesser thickness. Depending on the tufting technique used and the arrangement of the son colors in the tufting machine, the carpets may have different color patterns or have surface effects such as chevrons or other shapes. It is also possible to produce tufted carpets with a uniform, speckled appearance, for example by using son of different dye affinities.

Among these items, plain carpets are a particularly important variety. There may be mentioned, for example, plain mats made from yarns with at least two twisted ends, with cut hairs and of medium thickness. These carpets are usually called "Saxony".

Solid color carpets can be made from three types of raw materials. A first raw material consists of yarn dyed in the mass, colored by pigments introduced during the polymerization of the synthetic material. A second raw material consists of yarn dyed after spinning, for example by quenching in a dye bath. A third raw material consists of undyed yarn, dyeing being performed after the manufacture of the carpet. Carpets made using this technique are called "room dyed carpets". This technique is generally preferred because it offers great flexibility. It is thus possible to make a large number of undyed pieces, and to choose the color only in the last step.

One of the main difficulties encountered for the realization of plain carpets is the presence of stripes due to disparities in dyeing between the threads constituting tuft lines. The plain carpets thus generally have lines or bands more or less light or dark. This lack of appearance is generally more visible than the observed surface is large. The stripes have the direction that the threads are tufted. One solution proposed to avoid this scratch effect is to create deviations of the tufting lines so that the dye differences are not unidirectional and therefore do not cause the effect of scratches. The tufting crafts for the implementation of this technique are much more complicated and expensive than conventional devices. In addition, the tufting speed on these looms is very low compared to the usual speeds for the manufacture of plain mats.

Another way to avoid scratches is to control the homogeneity of dyeing son. For this purpose the conditions of manufacture of the son before dyeing are of great importance.

The processes for manufacturing saxony plain carpet yarns comprise, for example, the following steps: spinning a multifilament called "butt", stretching, texturing, twisting two or three ends, fastening the retorde. R. W. Miller (Textile Research Journal, February 1991, P62) teaches that texturing conditions have an influence on the marked character of stripes. In a later study (Textile Research Journal, February 1994, P76) he studied the influence of the retord fixation process on the presence of scratches. It compares for this purpose the two types of existing technologies: a technology according to which the fixing is carried out in a medium comprising superheated steam (in particular sold by Superba, and known under the general name "Superba-Set "), and a technology according to which the fixing is carried out in a heated medium containing no water vapor (in particular sold by the American Suessen Corporation, and known under the general name" Suessen-Set "). According to this study the first technology can reduce the scratch effect. The second technology does not give satisfactory results. These conclusions are confirmed by use, the Superba-Set technology being the most used for yarns intended to be tufted for the manufacture of plain carpets. There are also many publications on improvements to Superba-Set technologies. For example, the patent FR 2478150 of the company Superba which teaches to cause forced circulation of steam to avoid temperature heterogeneities. It is thus possible to reduce the amplitude of the color variations and thus to reduce the scratches. Although the amplitude of the color variations could be reduced, however, it was not possible to obtain tufted surfaces without scratches.

The object of the present invention is to propose a method of manufacturing a yarn intended for the manufacture of tufted articles, with which the plain colored tufted carpets do not present any scratches. To this end, the invention proposes a method of manufacturing a wire with at least two ends, comprising a step of manufacturing the ends by melt spinning a multifilament yarn of thermoplastic material, optionally drawing, texturing, a phase of assembling at least two ends per twist, and a retord fixing phase, characterized in that the texturing is carried out in an atmosphere containing superheated water vapor, and in that the retord is fixed by passage wire in a dry atmosphere of temperature between the glass transition temperature and the melting temperature of the thermoplastic material.

The multifilament yarns used as basic elements for the manufacture of yarn which will be used on the tufting machine after twisting and twisting are synthetic textured yarns. They are made by spinning a molten thermoplastic material through dies having a plurality of orifices. On leaving the die, the material is cooled and solidified. Methods and devices for melt spinning are well known to those skilled in the art. It is thus possible to spin multifilament yarns whose filaments have sections of different shapes: circular sections, flattened sections, trilobal sections, triangular sections, multi-lobed sections. The sections may also have one or more cavities.

Examples of materials that are suitable for the invention include polyamides, polyesters, polypropylenes, polyethylenes, their mixtures and copolymers.

By way of example of suitable polyesters for the invention, mention may be made of polyethylene terephthalate, polypropylene terephthalate), mixtures of polymers containing them and copolymers containing a majority of repeating units similar to those of these polymers.

By way of example of polyamides or copolyamides which are suitable for the invention, mention may be made of poly (hexamethylene adipamide), polycaprolactam, copolymers of these two polyamides or their mixtures. These polyamides may also comprise other repeating units such as sulfonate aromatic units such as the repeating unit derived from 5-isophthalic acid or the like, or units derived from other dicarboxylic acids such as iso or terephthalic acids or diamine.

Other polyamides may also be mentioned, such as PA 6.10; PA 4.6, PA11 or PA12.

The thermoplastic material can comprise various additives such as pigments, mattifying agents, reinforcing fillers, heat or light stabilizing agents, heat protection agents, antimicrobial agents, anti-fouling agents or the like. The yarns may thus contain particles based on titanium dioxide, in a proportion of 0.1% to 2% by weight, preferably 0.3 to 1.6% by weight. The list of additives and fillers that can be used is not exhaustive.

The cooling and solidification phase of the thermoplastic material may be carried out by passing the wire in a gaseous or liquid medium. The son is for example subjected to a flow of air between the die and the first point of call of the wire. This operation can also be performed in the presence of steam, introduced under the die.

According to a particularly advantageous embodiment, the cooling and solidification phase is carried out by passing the wire in a liquid medium, for example water. For this purpose, the wire may be previously cooled in a gaseous zone, for example between 9 and 20 mm of the die, and then solidified in water, preferably between 40 ° C. and 50 ° C. The filaments produced according to this method generally have a surface appearance of orange peel.

After spinning and solidification, the multifilament yarn is optionally stretched, for example by driving the yarn between several rollers of increasing rotational speeds.

The multifilament yarn is textured to give it a crimp. The crimp generally makes it possible to modify the appearance of the surfaces that will be made from the wire. All known texturizing processes in superheated steam atmosphere or in air / vapor atmosphere can be used. For example, it is possible to mention the methods of crimping by crushing in a texturizing box, the texturizing processes by passing the wire through a nozzle or a nozzle with a jet of steam. A texturing method suitable for the invention is for example described in the patent FR2041654. The yarns are, for example, textured in the presence of an air-vapor mixture whose temperature is between 150 ° C. and 190 ° C. After texturing, the multifilament yarns advantageously contain at least 2.5% by weight of moisture, preferably at least 3%. .

The multifilament yarns for the invention are generally referred to as "BCF" type yarns (Bulk Continuous Filament). These are continuous filament yarns whose volume has been increased by heat treatment during a subsequent spinning step. The increase in the volume of the filaments may for example occur during the phase of fixing the twist.

The titles of the multifilament yarns used according to the invention can be between about 600 dtex and 6000 dtex, with 6 to 200 filaments. Filament counts are generally between about 5 dtex and 420 dtex. The textured multifilament yarn is twisted together with at least one other multifilament yarn, preferably identical. The yarn obtained is therefore composed of at least two associated yarns. These associated threads are individually called "ends". The ends may advantageously individually present a twist or entanglement. Such individual twists or entanglements are intended to give the ends a better cohesion of the filaments.

The twisting operation to assemble the ends is to wind the ends around each other on a regular basis. Methods, devices and typologies of retord are well known to those skilled in the art. By way of example, mention may be made of so-called "double twist" or "uptwist" devices, as well as so-called "direct wiring" devices. Such devices are for example marketed by the companies Volkman and I.C.B.T. For yarns subsequently undergoing a retord fastening, the direct wiring technique is generally preferred. The edges are distinguished by the direction of winding (direction "S" or direction "Z") and by the number of turns per unit length of the wire.

When each of the tips has an individual twist, the direction of the twist of the ends together is preferably opposite to the direction of twist of the ends taken individually.

For example, the yarns generally used for the manufacture of tufted articles, and preferably for the manufacture of cut pile articles, comprise two or three ends twisted in a S or Z direction, with a twist of 180 trlm. at 300 rpm.

The retord fixing step is performed by passing the twisted yarn in a hot and dry atmosphere. Dry atmosphere means an atmosphere containing no more water vapor than the ambient air. The hot atmosphere can be air, nitrogen or oxygen-depleted air. The temperature at which the wire is subjected to passage through the hot atmosphere is advantageously greater than the glass transition temperature of the synthetic material. It is preferably greater than 150 C, more preferably greater than 170 C, for a polyamide-based yarn. Any means or device for conveying a twisted yarn in a chamber defining a dry and hot medium may be used. For example, the twisted yarn may be conveyed in an oven having openings for the entry and exit of the yarn. The mode of transport of the wire in the enclosure is advantageously chosen so that the wire is treated as uniformly as possible with a residence time in the oven selected.

Devices suitable for the implementation of the invention are sold especially by the company Suessen Corporation, for example under the references GVA 2500 or GVA 5000. Such devices are for example described in US Patents 4507832, US 55467513, US 4513514. They are known to those skilled in the art under the name "Suessen Set". Briefly and schematically, the wire to be treated is entwined around several drive bands that pass through an oven. The temperature in the oven is chosen according to the nature of the treated yarn. At the furnace outlet, the wire entwined around the drive strips is for example ejected on a coil. By way of example, the temperature is between 200 ° C. and 215 ° C. for a yarn mainly made of polyamide 66, or between 185 ° C. and 205 ° C. for a yarn mainly composed of polyamide 6.

The yarns according to the invention are particularly usable for the manufacture of carpets of the "Saxony" type, that is to say of united carpets composed of cut hairs of medium thickness, the bristles being composed of at least two twisted ends. The thickness is generally between 8 and 12 mm. These carpets are made by the usual tufting techniques with an in-line construction from son composed of several twisted ends and whose twist is fixed by heat treatment. The gauge is for example between 5I32 "and 1I16". The stich is for example between 32 and 70, for 10 cm.

The carpets are advantageously dyed after the tufting operation. The dyeing may be carried out by continuous, semi-continuous or discontinuous processes, for example in a boat.

Other details or advantages of the invention will emerge more clearly in view of the examples given below solely for information purposes.

<U> Example 1 and Comparative Example 1 </ U> A multifilament yarn with a nominal title of 950 dtex, comprising 51 filaments, of polyamide 66, and containing 0.3% by weight of titanium dioxide, was melt spun with solidification by passage in water. The yarn was then stretched and textured: the texturing was performed by pneumatic piling under a jet of superheated steam, according to a method described in Patent FR2041654. The yarn was packaged in approximately 40 coils of 5 kg each. Humidity levels by weight at different points of the coils were measured: 3.2% outside the coil, 4.3% in the middle of the coil, 5.5% inside the coil.

A twisted yarn was then made at two ends from the multifilament yarn thus obtained on a direct-caged twister sold by I.C.B.T. The twisting was 240 rpm. The twisted yarn was separated into two substantially identical batches for the respective implementation of Example 1 and Comparative Example 1.

For example 1 the retord was fixed by heat treatment in a dry atmosphere using the device GVA 2500 marketed by the company Hdrauf-Suessen. The treatment temperature was 205 ° C. The twist of the wire after this step was 248 trlm. The yarn was packaged in about 400 coils of about 250 g to produce a tufted surface of 1 × 10-gauge, stick 35, about 1 meter wide, and the tufted surface was dyed by boat using a conventional method. stained surface showed no scratches.

For Comparative Example 1, the retord was set by heat treatment in the presence of steam, using a device marketed by Superba establishments. Twisting of the wire after this step was 260 trlm. The yarn was packaged in about 400 rolls of about 250 g to make a tufted surface of gauge 1110, stick 35, about 1 m wide, and the tufted surface was tried in a boat by a conventional method. dyed surface exhibited numerous scratches due to dyeing disparities.

<U> Example 2 and Comparative Example 2 </ U> A multifilament yarn with a nominal title of 950 dtex, comprising 51 filaments, of polyamide 66, and containing 0.3% by weight of titanium dioxide, was melt spun with solidification by passage in water. The yarn was then stretched and textured: the texturing was performed by pneumatic piling under a jet of superheated steam, according to a process described in Patent FR2041654. About 10 tons of yarn were spun and packed in reels.

The multifilament yarn was separated into two substantially identical batches for the implementation of Example 2 and Comparative Example 2.

For Example 2, a two-end twist was made at approximately 252 μm on a direct-caged twister sold by the company ICBT The retord was fixed by heat treatment in a dry atmosphere using the GVA 2500 device marketed by the company Hérauf-Suessen. The treatment temperature was 205 ° C. The twist in the wire after this step was 260 rpm. The yarn was packaged in about 1600 bobbins of about 3 kg each to make a tufted 1,10 ", stick 35 surface, about 4 m wide, and the tufted surface was dyed by boat in a conventional manner. The dyed surface showed no scratches.

For Comparative Example 2, a double-ended twist at about 240 μm was performed on a direct-caged twister sold by the company ICBT The retord was fixed by heat treatment in the presence of water vapor at using a device marketed by Superba establishments. Twisting of the wire after this step was 260 rpm. The yarn was packaged in about 1600 bobbins of about 3 kg each to make a tufted surface of <B> 1 </ B> I10 gauge, stick 35, about 4 m wide. tinting in a boat according to a conventional method The tinted surface showed scratches due to dyeing differences.

<U> Comparative Examples 3 and 4 </ U> A multifilament yarn with a nominal strength of 950 dtex, comprising 51 filaments, of polyamide 66, and containing 0.3% of titanium dioxide was melt spun with solidification at 1 'air. The yarn was then spun and textured: the texturing was carried out by pneumatic packing in a dry atmosphere at about 190 ° C. The yarn was packaged in about 40 rolls of 5 kg each. Humidity levels by weight at different points of the coils were measured: 2% outside the coil, 1.8% in the middle of the coil, 1.2% inside the coil.

A twisted yarn was then made at two ends from the multifilament yarn thus obtained on a direct-caged twister sold by I.C.B.T. The twisting was 240 rpm. The twisted yarn was separated into two substantially identical batches for the respective implementation of Comparative Example 3 and Comparative Example 4.

For Comparative Example 3 the retord was fixed by heat treatment in a dry atmosphere using the GVA 2500 device marketed by Hérauf-Suessen. The treatment temperature was 205 ° C. The twist of the wire after this step was 248 trlm. The yarn was packaged in about 400 coils of about 250 g to make a tufted surface of gauge 1110, stitch 35, about 1 meter wide, and the tufted surface was dyed by a conventional method. dyed surface exhibited numerous scratches due to dyeing disparities.

For Comparative Example 4, the retord was set by heat treatment in the presence of steam, using a device marketed by Superba establishments. Twisting of the wire after this step was 260 trlm. The yarn was packaged in about 400 coils of about 250 g to make a tufted surface of gauge 1110, stich 35, about 1 m wide, and the tufted surface was tried in a boat by a conventional method. dyed surface exhibited numerous scratches due to dyeing disparities.

<U> Example 3 </ U> A multifilament yarn of nominal strength of 1060 dtex, comprising 51 filaments, of polyamide 66, and containing 0.6% by weight of titanium dioxide, was melt spun with solidification per pass in water. The yarn was then stretched and textured: the texturing was performed by pneumatic piling under a jet of superheated steam, according to a process described in Patent FR2041654. About 8 tons of yarn were spun and packed in reels. A twisted yarn was then made at two ends from the multifilament yarn thus obtained on a direct-caged twister sold by I.C.B.T. The retord was 248 trlm.

The retord was fixed by heat treatment in a dry atmosphere using the 48-position GVA 5000 device marketed by the HSrauf-Suessen company. The treatment temperature was 205 ° C, with a dew point at 96 ° C and a residence time in the device of about 50s. The yarn was packaged in about 2000 rolls of about 4 kg to make a tufted surface of 1/10 "gauge, stich 42, about 5 meters wide and 160 meters long The tufted surface was dyed by a process The dyed surface did not show any scratches.

Claims (10)

<U> CLAIMS </ U> 1. A method of manufacturing a wire with at least two ends for the manufacture of tufted articles, comprising a phase of manufacture of the ends by melt spinning of a multifilament yarn of thermoplastic material, optionally stretching, texturing, a phase of assembling at least two ends by twist, and a retord fixing phase, characterized in that the texturing is carried out in an atmosphere containing superheated water vapor, and in that the retangle is fastened by passing the wire in a dry atmosphere of temperature between the glass transition temperature and the melting temperature of the thermoplastic material. 2. Method according to claim 1 characterized in that the multifilament yarn is solidified at the die outlet by passing through water. 3. Method according to one of the preceding claims characterized in that the thermoplastic material is selected from polyamides, polyesters, polypropylene. 4. Method according to claim 3 characterized in that the thermoplastic material is mainly composed of polyamide 66 and in that the retord fixing temperature is between 200 C and 215 C. 5. Method according to claim 3 characterized in that the thermoplastic material is mainly composed of polyamide 6 and in that the retord fixing temperature is between 185 C and 205 C. 6. Method according to one of the preceding claims characterized in that the thermoplastic material comprises at least 0.1% by weight of titanium dioxide particles. 7. Method according to one of the preceding claims characterized in that the texturing is performed in an atmosphere containing a mixture of air and steam at a temperature between 150 C and 190 C. 8. Method according to one of the preceding claims characterized in that the retord fixing is carried out using a Suessen-set type device. 9. Yarns obtainable by a method according to one of claims 1 to 8. Tufted article made from yarns according to claim 9.