CH441605A - Process for crimping thermoplastic yarns - Google Patents

Description

Process for crimping thermoplastic yarns Main patent NO 378459 relates to a process for crimping thermoplastic yarns by packing and compressing them in a restricted space, characterized by the fact that the crimping yarn is introduced at one end. an enclosure by means of a stream of pressurized fluid, heated to a temperature ensuring the fixing of the thread, that this thread is piled up in this enclosure under the effect of the fluid, part of which escapes laterally through convenient orifices in the wall of the enclosure and that, by means of the other part of the fluid, the thread thus piled up is compressed and then expelled from this enclosure, by the other end.

This process, which is also described in French patent no. contact with the compressed fluid stream.

The fluid used can be a hot liquid under pressure.

However, it has been found that it is possible to obtain crimped yarns possessing even better mechanical characteristics, if one implements the process of the main patent by introducing, into the enclosure where it is piled up, at least one crimping yarn and an auxiliary yarn fed at a speed lower than that of the crimping yarn, by subjecting the composite yarn obtained to an additional fixing heat treatment, then by separating the auxiliary yarn from the composite yarn.

It is true that French Patent No. 1264506 proposes a process for crimping thermoplastic yarns with the use of a transitional yarn. However, in the procedure of this patent, the transitional yarn is a multi-filament Support On which the loops of the thermoplastic yarn are generated and become anchored, and in the absence of which there would be no crimping of the thermoplastic yarn. . This patent therefore did not in any way suggest that the use of an auxiliary yarn in the process of the main patent would produce favorable effects. In addition, the process of the aforementioned French patent does not allow RTI ID="0001.0277" WI="5" HE="4" LX="1338" LY="1484"> not to reach speeds of pro - high reduction and hardly suitable for crimping headline yarns or wicks.

To implement the process according to the present invention, one can use the device described in Swiss patent NO 387868. - pendants.

As in the main patent, the crimping yarn can be amended at speeds up to 1000 meters per minute and more. The feed speed of the auxiliary thread is much lower, eg 0.4-2.5% of the speed of the crimping thread. When several yarns to be crimped are sent into the injector, the fine speed of these various yarns can be equal: in this case, after dissociation from the auxiliary yarn, one obtains a crimped lock whose number of filaments is is the sum of the number of filaments of the crimping yarns introduced into the enclosure.

It is thus possible to obtain, with several yarns, curly locks with large titles without it being necessary to preassemble these yarns.

It is also possible to dissociate the lock obtained into its various constituents: contrary to what one might have thought, this dissociation is carried out without difficulty. This makes it possible, for the same setting of the device, to prepare curly yarns of different counts. If the feed speed of the various crimping yarns is different, after separation from the auxiliary yarn, a fancy yarn of the chenille type is obtained, the crimping yarn introduced with the slowest speed constituting the core yarn. , the other or the other the effect wire.

The adjustment conditions of the apparatus are the same as in patents No. 378459 and 387868. On leaving the crimping enclosure, the composite yarn is sofft rewound, sofft collected as it is, for example in a rotating pot, to eire subjected to the heat treatment of complementary fixation.

Since the auxiliary yarn is only transitory, it is better to reduce the percentage in the composite yarn. This percentage can be as low as 0.01-0.05% by weight, although it could conveniently be slightly higher. The possibility of using a very low percentage of auxiliary yarn is one of the advantages of the present process because, whatever the method then used to eliminate this yarn, the risks of impurities remaining in the crimped yarn are reduced.

The complementary fixing of the composite yarn can be done by stoving ä. steam at a temperature varying with the nature of the yarn.

When dealing with composite yarns intended to be dyed, the additional heat setting of the composite yarn can be carried out during the dyeing operation. The compact shape of the composite EI, due to the great difference in the feed into the injector of the auxiliary yarn and of the curling yarn, does not harm the good penetration of the dye. The crimped yarn that is taken up, after unraveling, offers a good evenness, and the articles made from this yarn do not present any irregularity in hue. This variant of the process is particularly economical since it makes it possible to carry out two treatments in a single operation.

In order to reduce as far as possible the number of manipulations necessary, it is advantageous to collect the composite yarn, on leaving the crimping device, directly in a perforated stainless steel basket of the type commonly used in dyeing.

The unraveling of the composite yarn, that is to say the dissociation of its constituents, can be carried out by various methods, such as - dissolution of the auxiliary yarn (in particular when the latter is in acetate of RTI ID="0002.0279" WI="13" HE="4" LX="1566" LY="684"> cellulose or polyvinyl alcohol).

- fusion of the auxiliary thread, when the latter has a relatively low melting point (polyethylene for example).

- mechanical process causing, by traction, the breaking of the auxiliary thread, which forms short strands which can be separated (for example, by electrostatic means), or which eliminate themselves during textile treatments later. Like the process of the main patent No. 378459, this improvement applies to all thermoplastic yarns, of any nature, and such in particular as those based on polyamide, polyesters, polyolefins, polyacrylic derivatives or polyvinyl, acetate or cellulose triacetate.

In addition to the advantage of a voluminous crimp provided with loops and waves in phase between the different strands, the yarns obtained according to the process of the invention have better mechanical characteristics (in particular a high resilience). than those of the son obtained according to the first process of the main patent and which make them very interesting for the manufacture of carpets. The following tables summarize the results obtained in a series of tests carried out using the apparatus of main patent No. 387868; the abbreviations appearing in these tables have the following meanings p = pressure in kg/cm2 of the fluid sent to the injector t = temperature of the fluid ( C) V = feed speed of the wires in m/min PA = polyhexamethylene adipamide PP = polypropylene PE = ethylene terephthalate Ac = cellulose acetate Vis = viscose (The figures appearing after these symbols each time indicate the count in deniers and the number of strands of the yarn.) The twist of the yarns used is each time less than or equal to 20 turns/meter. The driving speed of the camposite yarn is substantially equal to the speed of passage of the auxiliary yarn.

The unraveling of the composite yarn is carried out in all cases by subjecting it to a tension sufficient to cause the breakage of the auxiliary yarn.

In the examples, compiled in Table I, a single crimping yarn was sent to the injector.

<I>Table 11</I> Example Auxiliary yarn Crimping yarn Fluid NO Nature V Nature V Nature p to 12 PA 20/7 5.8 2 ends PP-450/30 300 steam 5 158 In example 12, shown In Table 1I, the crimping threads are fed into the injector at the same speed: after steaming and unthreading, the crimped lock is returned.

<I>Table 111</I> Example Auxiliary yarn Crimping yarn Fluid Na Nature V Nature V Nature p to 13 Screw 60/20 4 2 ends PA 520/30 400 steam 3.5 147 In example 13, shown in in Table III, the crimping yarns are fed to the same speed through the injector; but after parboiling and milage, crimped yarns are wound onto two separate spools.

<I>Table IV</I> Curling yarns Example Auxiliary yarn 1st yarn (ame) 2nd yarn (effect) Fluid No$ Nature V Nature V Nature V Nature p to 14 Vis 60/20 3.5 PA 1040/60 25 PA 1040/ 60 200 steam 3.5 147 15 Vis 60/20 3.5 PA 1040/60 25 Ac 900/ 72 200 steam 3.5 147 16 Ac 75/24 3 PA 520/30 100 PP 450/ 30 350 steam 3143 17 Ac 75/24 3 PA 520/30 100 PE 1000/200 200 steam 3143 In Examples 14-17, shown in Table IV, the curling Pils were fed at different speeds through the injector; after steaming and drying, the yarns obtained are fancy yarns of the chen:lle type. Example <I>18</I> In this example the additional heat fixing and dyeing are carried out in one operation.

Ort prepares a composite yarn from a 1040 denier, 60 ply polyhexamethylene adipamide yarn and a 75 denier 24 ply cellulose acetate yarn.

The feed speed of the polyamide yarn to the injector is 400 m/min, the speed of the cellulose acetate yarn 4 m/min.

The fluid sent to the injector is steam, heated to 147) under 3.5 kg/cm2 of pressure. The composite yarn is collected in a perforated stainless steel basket.

Ort carries out a desensitization at 90° C. with an aqueous solution comprising, per liter, 5 cm3 of NaOH at 36° B6 and 2 cm3 of a nonionic detergent of a common type.

After rinsing, followed by neutralization with acetic acid, the basket containing the yarn is introduced into a pressure dyeing apparatus of a common type, a bath autoclave machine.

The dye bath, brought to pH 4 by addition of acetic acid, contains 0.7 ()/o of Saune Irgalane GL (C. I. Acid Yellow 114, 2nd 6d. 1956) 0.05% of Orang6 Cibalane RL (C. I. Acid Orange 88, 2nd 6d. 1956) 0.18% Gris Irgalane BL (C. I. Acid Black 58, 2nd 6d. 1956) relative to the material to be dyed, and 1.25 g/litre of the product sold under the Tintogil RM brand -75 .

In one hour, the temperature is brought to 130° C., then maintained at this value for one hour. After ringing and drying, the composite yarn is unwrapped, then unwound.

Ort collects a dyed yarn, moss green, whose crimp is stable.

Claims (1)

CLAIM Process for RTI ID="0004.0256" WI="3"HE="4" LX="1404" LY="2103"> the first crimping of thermoplastic yarns according to the claim of the main patent, characterized by the fact that Fon introduces, in the enclosure where it is piled up, at least one crimping yarn and an auxiliary yarn brought to a speed lower than that of the crimping yarn, that the composite yarn obtained is subjected to a complementary fixing heat treatment, then that the first auxiliary yarn is separated from the composite yarn. Opposing writings and images pending French Patent Nos <I>1264 506,</I> 1289<I>491</I>