WO2001027366A1

WO2001027366A1 - Method for producing threads for tufted items

Info

Publication number: WO2001027366A1
Application number: PCT/FR2000/002868
Authority: WO
Inventors: Michel Dupire; Boukhalfa Guirous; Adianus Arnoldus Van Uden
Original assignee: Rhodia Performance Fibres
Priority date: 1999-10-14
Filing date: 2000-10-13
Publication date: 2001-04-19
Also published as: FR2799768A1; FR2799768B1; EP1238127A1; AU7800800A

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 manufacturing yarns for tufted articles.

The present invention relates to a method of manufacturing yarns for the production of articles intended for tufting, and more particularly of solid colored carpets, dyed after the tufting operation.

Tufted articles are mainly used to cover large surfaces, floors or walls. The tufting technique is one of the preferred techniques for manufacturing large items because it is economical and easily industrializable. Many developments have therefore been made in order to give the articles the desired aspects. There are, for example, "looped" carpets, "cut" carpets of varying thickness. According to the tufting technique used and according to the arrangement of the colors of threads in the tufting machine, the carpets can have patterns of different colors or have surface effects, for example in the form of chevrons or other figures. It is also possible to make tufted carpets with a plain, speckled appearance, for example using threads of different dye affinities.

Among these items, plain rugs are a particularly important variety. We can cite, for example, plain carpets made from yarns with at least two twisted ends, cut pile and 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 soaking in a dye bath. A third raw material consists of undyed yarn, the dyeing being carried out after the manufacture of the carpet. Carpets made using this technique are called "piece dyed rugs". This technique is generally preferred because it offers great flexibility. It is thus possible to produce a large number of undyed pieces, and to choose the color only during the last step. One of the main difficulties encountered in the production of plain rugs is the presence of scratches due to dye disparities between the threads constituting the tuft lines. Plain carpets thus generally have more or less light or dark lines or bands. This defect in appearance is generally all the more visible the larger the area observed. The stripes have the direction in which the threads are tufted. One solution proposed to avoid this striping effect is to create deviations from the tufting lines so that the dye disparities are not unidirectional and therefore do not cause the striping effect. Tufting looms 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 carpets. In addition, to obtain the same density of pile surface of the carpet, it is necessary to use more threads, which increases the cost of the surfaces.

Another way to avoid scratches is to control the dye homogeneity of the threads. To this end, the conditions of manufacture of the threads before dyeing are of great importance.

The processes for manufacturing threads for plain carpets of the Saxony type include, for example, the following steps: Spinning of a multifilament called "end", drawing, texturing, twisting of two or three ends, fixing of the twist. RW Miller (Textile Research Journal, February 1991, P62) teaches that the texturing conditions have an influence on the marked character of the stripes. In a later study (Textile Research Journal, February 1994, P76) he studies the influence of the twist fixing 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 of superheated water vapor (in particular marketed by the company Superba, and known under the general name of "Superba-Set "), and a technology according to which the fixing is carried out in a heated medium not comprising water vapor (in particular marketed by the company American Suessen Corporation, and known under the general name of" Suessen-Set "). According to this study, the first technology makes it possible to reduce the scratch effect. The second technology does not give satisfactory results. These conclusions are confirmed by usage, the Superba-Set technology being the most used for yarns intended to be tufted for the manufacture of plain carpets. There are also numerous publications on improvements made to Superba-Set type technologies. One can for example quote the patent FR 2478150 of the company Superba which teaches to cause a forced circulation of the vapor in order to avoid heterogeneities of temperature. It is thus possible to reduce the amplitude of the color variations and therefore to reduce the stripes. Although the amplitude of the color variations could be reduced, it was not possible to obtain tufted surfaces that did not show scratches. The object of the present invention is to propose a method for manufacturing a thread intended for the manufacture of tufted articles, with which the plain colored tufted carpets do not have any scratches.

To this end, the invention provides a method of manufacturing a wire with at least two ends, comprising a phase of manufacturing the ends by melt-spinning a multifilament wire of thermoplastic material, optionally drawing, texturing, a phase of assembly of at least two ends by twist, and a phase of fixing the twist, characterized in that the texturing is carried out in an atmosphere containing superheated steam, and in that the fixing of the twist is carried out by passage wire in a dry atmosphere with a temperature between the glass transition temperature and the melting temperature of the thermoplastic material.

The multi-member yarns used as basic elements for the manufacture of the yarn which will be used on the tufting machine after twist assembly and twist attachment are textured synthetic yarns. They are produced by spinning a molten thermoplastic material through dies having several orifices. At the outlet of the die, the material is cooled and solidified. The processes and devices for melt spinning are perfectly known to those skilled in the art. It is thus possible to spin multi-parliamentary threads, the filaments of which have sections of different shapes: circular sections, flattened sections, trilobed sections, triangular sections, multi-lobed section. The sections can also have one or more cavities.

As examples of materials suitable for the invention, mention may be made of polyamides, polyesters, polypropylenes, polyethylenes, their mixtures and copolymers.

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

By way of example of polyamides or copolyamides suitable for the invention, mention may be made of poly (hexamethylene adipamide), polycaprolactam, the copolymers of these two polyamides or their mixtures. These polyamides can also comprise other repeating units such as aromatic sulfonate 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 can also be mentioned, such as PA 6.10; PA 4.6; PA 11 or PA 12.

The thermoplastic material can comprise various additives such as pigments, matifiers, reinforcing fillers, heat or light stabilizing agents, heat protection agents, antimicrobial agents, anti-fouling agents or the like. The strands can thus contain particles based on titanium dioxide, in a proportion of 0.1% to 2% by weight, preferably from 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 can be carried out by passing the wire through a gaseous or liquid medium. The wire is for example subjected to an air flow between the die and the first point of call of the wire. This operation can also be carried out 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 through a liquid medium, for example water. To this end, the wire can be previously cooled in a gaseous zone, located for example between 9 and 20 mm from the die, then solidified in water, with a temperature preferably between 40 ° C and 50 ° C. The filaments produced according to this process generally have an orange peel surface appearance.

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

The multifilament yarn is textured to give it crimp. Crimping generally makes it possible to modify the appearance of the surfaces which will be produced from the wire. All known methods of texturing in an atmosphere of superheated steam or in air / steam atmosphere can be used. We can for example cite the methods of crimping by piling up in a texturing box, the texturing methods by passing the wire through a nozzle or a nozzle with a jet of steam. A texturing process suitable for the invention is for example described in patent FR2041654. The threads are, for example, textured in the presence of an air / vapor mixture the temperature of which is between 150 ° C. and 190 ° C., preferably between 165 ° C. and 175 ° C. After texturing, the multi-member yarns advantageously contain at least 2.5% by weight of moisture, preferably at least 3%.

Multi-parliamentary yarns for the invention are generally qualified as "BCF" (Bulk Continuous Filament) type yarns. These are continuous threads made up of filaments whose volume has been increased by a heat treatment during a step subsequent to spinning. The increase in the volume of the filaments can, for example, occur during the torsion fixing phase. The titles of the multi-parliamentary threads used according to the invention can be between approximately 600 dtex and 6000 dtex, with 6 to 200 filaments. Filament titles are generally between approximately 5 dtex and 420 dtex.

The textured multifilament yarn is twisted together with at least one other multifilament yarn, preferably identical. The wire obtained therefore consists of at least two associated wires. These associated wires are individually called "tips". The ends can advantageously individually present a twist or an entanglement. Such individual twists or intertwining are intended to give the ends a better cohesion of the filaments. The twisting operation to assemble the ends consists of winding the ends around each other in a regular manner. The twisting methods, devices and typologies are well known to those skilled in the art. By way of example, there may be mentioned the so-called "double twist" or "uptwist" devices, as well as the so-called "direct wiring" devices. Such devices are for example marketed by the companies Volkman and I.C.B.T. For wires subsequently subjected to twisted fixing, the direct wiring technique is generally preferred. The twists are distinguished by the winding direction ("S" or "Z" direction) and by the number of turns per unit of length of the wire.

When each of the ends has an individual twist, the direction of the twisting of the ends between them is preferably opposite to the direction of torsion of the ends taken individually.

For example, the threads generally used for the manufacture of tufted articles, and preferably for the manufacture of articles with cut pile, have two or three ends twisted in an S or Z direction, with a twist of 180 tr / m to 300 rpm. We can observe a slight shrinkage after fixing the twist, so there is a slight increase in the number of turns per meter. According to preferential characteristics, the twist before shrinkage is less than 280 rpm for threads of less than 1100 dtex, 260 rpm for threads of more than 1100 dtex, 240 rpm for threads greater than 1400 dtex. The twist fixing step is carried out by passing the twisted yarn through a hot and dry atmosphere. By dry atmosphere is meant an atmosphere containing no more water vapor than the ambient air. The hot atmosphere can be air, nitrogen or oxygen-depleted air. The temperature to which the wire is subjected by passage through the hot atmosphere is advantageously higher than the glass transition temperature of the synthetic material. It is preferably greater than 150 ° C, more preferably still greater than 170 ° C, for a polyamide-based yarn. Any means or any device making it possible to convey a twisted yarn in an enclosure delimiting a dry and hot environment can be used. One can for example convey the twisted yarn in an oven comprising openings for the entry and exit of the thread. 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 chosen oven.

Devices suitable for implementing the invention are in particular marketed by the company Suessen Corporation for example under the references GVA 2500 or GVA 5000. Such devices are for example described in patents US 4507832, US 55467513, US 4513514. They are known to those skilled in the art under the name of "Suessen Set". Briefly and schematically, the wire to be treated is wrapped around several drive belts which pass through an oven. The temperature in the oven is chosen according to the nature of the wire treated. On leaving the oven, the wire entwined around the drive belts is returned, for example, to a spool. For example, the temperature is between 195 ° C and 215 ° C, preferably between 200 and 215 ° C, and even more preferably between 200 and 206 ° C for a wire mainly consisting of polyamide 66, or between 185 ° C and 205 ° C for a thread mainly made of polyamide 6. The fixing temperature can also have an effect on the swelling of the fiber (bulk) and the definition of the points of the carpet.

The dew point in the twist fixing atmosphere is preferably greater than 90 ° C, and even more preferably greater than 95 ° C.

The yarns according to the invention can in particular be used for the manufacture of "Saxony" type carpets, that is to say plain carpets composed of cut hairs of medium thickness, the hairs being composed of at least two twisted ends. The thickness is generally between 8 and 12 mm. These rugs are produced by the usual tufting techniques with in-line construction from yarns composed of several twisted ends and whose twist is fixed by heat treatment. The gauge is for example between 5/32 "and 1/16". The stich is for example between 32 and 70, for 10 cm.

The carpets are advantageously dyed after the tufting operation. Dyeing can be carried out by continuous, semi-continuous or discontinuous processes. One can for example use dyeing devices in a boat. The dyeing kinetics of the surfaces obtained from the yarns according to the invention may be slightly reduced compared to that observed with yarns obtained according to usual methods. It is preferable to use dye molecules of small to medium size, which migrate well in the thread. They may, for example, be acid dyes dyes. Mention is made, by way of example, of the Tectilon dye type molecules sold by the company Ciba. Tectilon F is preferably avoided. A migrant anionic unison agent can be used in combination with the dye. The pH of the dye solution is preferably between 5.8 and 6.2. The pH can be directly buffered to this value, or change during dyeing to reach these values. It can for example evolve from 8-8.5 at the start of dyeing, to around 6 at the end of dyeing. The pH profile over time can be continuous or have steps.

The dyeing time is preferably between 30 and 45 minutes, at a temperature plateau above 95 ^σ C. The temperature plateau can be preceded by a temperature ramp, for example at around 2 ° C / min and be followed by cooling. In the case of a dyeing with evolving pH, the temperature ramps can also be scalable, with possibly intermediate steps.

The surfaces tufted from the threads according to the invention, after dyeing do not show any scratches. The yarns, moreover, exhibit significant swelling, which improves their covering effect, with equal density of yarns (kg / m ² ) on a tufted surface. We can therefore prefer fairly open constructions.

Other details or advantages of the invention will appear more clearly in the light of the examples given below only for information.

Example 1 and Comparative Example 1

A multifilament yarn with a nominal titer of 950 dtex, comprising 51 filaments, made of polyamide 66, and containing 0.3% by weight of titanium dioxide, was melt melted with solidification by passage through water. The wire was then drawn and textured: the texturing was carried out by pneumatic piling under a jet of superheated steam, according to a process described in patent FR2041654 .. The wire was conditioned in approximately 40 spools of 5 kg each. Moisture 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 with two ends was then produced from the multifilament yarn thus obtained, on a direct-wiring twister marketed by the company I.C.B.T .. The twist 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 twist was fixed by heat treatment in a dry atmosphere using the GVA 2500 device sold by the company Hôrauf-Suessen. The processing temperature was 205 ° C. The wire twist after this step was 248 rpm. The yarn was packaged in approximately 400 spools of approximately 250 g to make a tufted surface of 1/10 "gauge, stich 35, approximately 1 meter wide. The tufted surface was dyed in a boat according to a usual process, under the following conditions:

- dyes: Yellow Tectillon MPR 200% (CIBA S.C.)

Red Tectilon 2B 200% (CIBA S.C.) Blue Tectillon 4R 200% (CIBA S.C.)

- Unison agent: Univadine NT (CIBA S.C.)

- pH buffered to 6

- Temperature: ramp from 25 ° C to 97 ° C at 1 ° C / min

Stall at 97 ° C for 30 minutes Cooling at 2 ° C / min

The tinted surface showed no scratches.

For Comparative Example 1, the twist was fixed by heat treatment in the presence of water vapor, using a device sold by Superba establishments. The wire twist after this step was 260 rpm. The yarn was packed in about 400 spools of about 250 g to make a tufted surface of 1/10 "gauge, stich 35, about 1 m wide. The tufted surface was dyed in a boat under the conditions of Example 1. The tinted surface had numerous scratches due to disparities in dyeing.

Example 2 and Comparative Example 2

A multifilament yarn with a nominal titer of 950 dtex, comprising 51 filaments, made of polyamide 66, and containing 0.3% by weight of titanium dioxide, was melt melted with solidification by passage through water. The yarn was then drawn and textured: the texturing was carried out by pneumatic piling under a jet of superheated steam, according to a process described in patent FR2041654. About 10 1 of yarn was thus spun and packaged 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 produced at approximately 252 rpm on a direct-wiring twister marketed by ICBT. The twist was fixed by heat treatment in a dry atmosphere using the GVA 2500 device sold by the company Hôrauf-Suessen. The processing temperature was 205 ° C. The wire twist after this step was 260 rpm. The yarn was packaged in about 1600 spools of about 3 kg each to make a tufted surface of 1/10 "gauge, stich 35, about 4 m wide. The tufted surface was dyed in a boat in conditions similar to those of Example 1. The tinted surface showed no scratches.

For Comparative Example 2, a twist at two ends was made at around 240 rpm on a direct-wiring twist sold by the company ICBT. The twist was fixed by heat treatment in the presence of water vapor, using a device marketed by Superba establishments. The wire twist after this step was 260 rpm. The yarn was packaged in about 1600 spools of about 3 kg each to make a tufted surface of 1/10 "gauge, stich 35, about 4 m wide. The tufted surface was dyed in a boat under conditions similar to those of Example 1. The dyed surface exhibited scratches due to disparities in dyeing.

Comparative examples 3 and 4

A multifilament yarn with a nominal titer of 950 dtex, comprising 51 filaments, made of polyamide 66, and containing 0.3% of titanium dioxide was melt-spun with solidification in air. The yarn was then spun and textured: the texturing was carried out by pneumatic piling in a dry atmosphere, at around 190 ° C. The wire was packaged in approximately 40 spools of 5 kg each. Moisture 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 with two ends was then produced from the multifilament yarn thus obtained, on a twister with direct wiring sold by the company ICBT. The twist 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 twist was fixed by heat treatment in a dry atmosphere to 1 using the GVA 2500 device marketed by Hôrauf-Suessen. The processing temperature was 205 ° C. The wire twist after this step was 248 rpm. The yarn was packed in about 400 spools of about 250 g to make a tufted surface of 1/10 "gauge, stich 35, about 1 meter wide. The tufted surface was dyed in a boat under similar conditions to those of Example 1. The dyed surface exhibited numerous scratches due to disparities in dyeing. For Comparative Example 4, the twist was fixed by heat treatment in the presence of water vapor, using 'A device sold by Superba establishments. The twist of the wire after this step was 260 rpm. The wire was packaged in approximately 400 spools of approximately 250 g to make a tufted surface of 1/10 "gauge, stich 35, about 1 m wide. The tufted surface was attempted in a boat under conditions similar to those of Example 1. The dyed surface exhibited numerous scratches due to disparities in dyeing. Example 5

A multifilament yarn with a nominal titer of 950 dtex, comprising 51 filaments, made of polyamide 66, and containing 0.3% by weight of titanium dioxide, was melt melted with solidification by passage through water. The yarn was then drawn and textured: the texturing was carried out by pneumatic piling under a jet of superheated steam, according to a process described in patent FR2041654. About 8 1 of yarn were thus spun and conditioned in reels.

A twisted yarn with two ends was then produced from the multifilament yarn thus obtained, on a twister with direct wiring sold by the company Volkman. The twist was 260 rpm.

The twist was fixed by heat treatment in a dry atmosphere using the 48-position GVA 5000 device sold by the company Hôrauf-Suessen. The treatment temperature was 203 ° C, with a dew point at 96 ° C and a residence time in the device of approximately 50s. The yarn was packaged in approximately 1600 spools of approximately 4 kg to make a tufted surface of 1/10 "gauge, stich 42, with a pile height of 7 mm after shaving, approximately 4 meters wide and 1600 m long.

200 m of the surface were dyed in a boat under conditions similar to those of Example 1. The dyed surface showed no scratches.

Claims

1. A method of manufacturing a thread with at least two ends for the manufacture of tufted articles, comprising a phase of manufacturing the ends by melt-spinning a multifilament thread of thermoplastic material, optionally drawing, texturing, a phase d assembly of at least two ends by a twist, and a twist fixing phase, characterized in that the texturing is carried out in an atmosphere containing superheated steam, and in that the fixing of the twist is carried out by passage of 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 outlet of the die by passage through water.

3. Method according to one of the preceding claims, characterized in that the thermoplastic material is chosen from polyamides, polyesters, polypropylene.

4. Method according to claim 3 characterized in that the thermoplastic material is mainly composed of polyamide 6 and in that the fixing temperature of the twist is between 185 ° C and 205 ° C.

5. Method according to claim 3 characterized in that the thermoplastic material is mainly composed of polyamide 66 and in that the fixing temperature of the twist is between 195 ° C and 215 ° C.

6. Method according to claim 5 characterized in that the fixing temperature is between 200 and 206 ° C.

7. Method according to one of claims 1 to 6 characterized in that the dew point the atmosphere in which the fixing is carried out is greater than 90 ° C.

8. Method according to one of the preceding claims characterized in that the thermoplastic material comprises at least 0.1% by weight of particles of titanium dioxide.

. Method according to one of the preceding claims, characterized in that the texturing is carried out in an atmosphere containing a mixture of air and water vapor at a temperature between 150 ° C and 190 ° C.

10. Method according to one of the preceding claims characterized in that the fixing of the twist is carried out using a device of the Suessen-set type.

11. Yarns capable of being obtained by a process according to one of claims 1 to 8.

12. Tufted article made from yarns according to claim 9.