DE102008051738A1 - PTT fiber with improved crimping - Google Patents

Abstract

The PTT fiber is spun conventionally. In the new process it is stretched at up to 70[deg] C. Following stretching and before entry into the crimping chamber it receives no heat treatment. It is preferably held to a temperature no greater than 85[deg] C. When in the crimping chamber it is heated, reaching a temperature up to 100[deg] C. During crimping it is fixed whilst still in the crimping chamber. The temperature during stretching is up to 60[deg] C and after stretching up to 70[deg] C. The temperature before entry into the crimping chamber is up to 70[deg] C, preferably up to 60[deg] C and most especially between room temperature and 40[deg] C. In the crimping chamber the temperature is up to 95[deg] C, preferably being held in the range 85-90?C. It is then fixed by introducing superheated steam. Before entering the crimping chamber the fibers are preheated to a temperature at least 20[deg] C greater than that after stretching, but to no more than 85[deg] C; further alternative temperature conditions are cited. Steam is used for heating in the crimping chamber. The individual filament titer of the PTT fiber filaments is preferably about 2.4 dtex. 3.9-8.9 crimps/cm are produced, preferably 5.5 crimps/cm. The crimping ratio (delta l/L) is preferably at least 17%. Following fixing, the PTT fibers are cut and used as staple fibers. An independent claim IS INCLUDED FOR the PTT fibers so produced.

Description

The The invention relates to a method for producing crimped Polytrimethylene terephthalate ("PTT") fibers with improved crimping and by this invention Process produced PTT fibers, in particular staple fibers, the suitable for yarns and other textile applications, as well Textile products from these yarns, but also by this invention Process produced PTT fibers that are suitable for filling fibers and products made from these filler fibers.

polyethylene terephthalate ("PET") and polybutylene terephthalate ("PBT"), commonly referred to as "polyalkylene terephthalates", are ordinary commercial polyesters. polyalkylene have excellent physical and chemical properties, Heat and light resistance, high melting points and high Strength. Consequently, they have always been on a broad basis used for technical and textile applications.

by virtue of increased raw material costs have polytrimethylene terephthalate ("PTT") increasing commercial interest gained as fiber material, because recently in the low cost area the development went to 1,3-propanediol (PDO), which is one of the monomer components the polymer backbone of PTT. For a long time you had wanted PTT in fiber form due to its disperse dyeability Atmospheric pressure, its low bending modulus, its elastic Recreation and its elastic resilience feature available to have.

While commercial availability of PTT fibers is relatively new, research has been ongoing for a long time. For example, this describes British Patent No. 1,254,826 Polyalkylene filaments, staple fibers and yarns, including PTT filaments and staple fibers. The main subject matter is carpet pile materials and fiber fillers. Described are the introduction of a filament bundle into a stuffer box texturing apparatus, the heat treatment of the crimped product in the form of a tow, being subjected to temperatures of about 150 ° C for a period of 18 minutes, and cutting the heat-fixed cable to staple lengths of 6 each Inch.

EP 1 016 741 describes the use of a phosphorus-containing additive and certain limiting constraints to achieve better whiteness, melt and spin stability in PTT polymers. The filaments and short fibers produced after spinning and stretching receive a heat treatment at 90-200 ° C.

JP 11-107081 describes the relaxation of an undrawn fiber of a PTT multifilament yarn at a temperature below 150 ° C, preferably at 110-150 ° C, for 0.2 to 0.8 seconds, preferably for 0.3 to 0.6 seconds, with a subsequent one False-twist texturing of the multifilament yarn.

JP 11-189938 describes the preparation of PTT short fibers (3-200 mm) and a wet heat treatment operation at 100-160 ° C for 0.01 to 90 minutes or a dry heat treatment operation at 100-300 ° C for 0.01 to 20 minutes. In working example 1, a PTT fiber is spun at 260 ° C. at a yarn spinning take-up speed of 1800 m / min. After stretching, the fiber is subjected to a heat treatment at 150 ° C in a liquid bath for 5 minutes to obtain a constant length. Then it is curled and cut. Working Example 2 illustrates the treatment of the drawn fibers with a dry heat treatment at 200 ° C for 3 minutes.

In U.S. Patent No. 3,584,103 describes a method for melt-spinning asymmetric birefringence PTT filaments. Spirally-crimped textile fibers of PTT material are made by melt-spinning filaments so as to have asymmetric birefringence throughout their diameter, the filaments, by stretching, being given a molecular orientation, the drawn filaments are heat-treated at 100-190 ° C while they are being drawn are kept at a constant length, and wherein the heat-treated filaments for 2-10 minutes in a relaxed state at more than 45 ° C, preferably at about 140 ° C, are heated.

EP 1 230 450 describes crimped PTT staple fibers with high tear resistance. The fibers are spun at a temperature of 245 to 285 ° C into filaments which are quenched and then preferably drawn according to a two-step process at a first temperature of 10 ° to 50 ° C and at a second temperature of 70 ° to 150 ° C. The patent teaches a treatment of the fibers by heat treatment, preferably after drawing and before crimping, at temperatures of 85 to 115 ° C. The drawn filaments are crimped with a steam-assisted mechanical crimper to a crimp degree of 3 to 12 crimps per cm, relaxed at a temperature of 50 to 120 ° C, and then cut into staple fibers. The staple fibers are 0.8 to 6 denier (0.88 to 6.6 dtex) per filament. The crimp pick-up is preferably 10% and above. The tear strength is at least 3.5 grams per denier (3.1 cN / dtex).

EP 1 230 451 describes a process for producing a fibrous web, a fiber fabric or a fiber filling product from crimped PTT staple fibers. The fibers are spun at a temperature of 245 to 285 ° C into filaments which are quenched and then preferably drawn according to a two-step process at a first temperature of 10 ° to 50 ° C and at a second temperature of 70 ° to 150 ° C. The patent teaches a heat treatment of the fibers, preferably after drawing and before crimping, at temperatures of 85 to 115 ° C. The drawn filaments are crimped with a steam-assisted mechanical crimper to a crimp degree of 3 to 12 crimps per cm, relaxed at a temperature of 50 to 130 ° C, and then cut into staple fibers. The crimp pick-up is preferably 10% and above, the tear strength is at least 3.0 grams per denier (2.65 cN / dtex).

According to both documents EP 1 230 450 and EP 1 230 451 For example, the PTT fibers are subjected to elevated temperature both during drawing and before entering the crimping chamber. The stretching takes place according to both rights at a temperature of more than 70 ° C and before entering the crimping chamber, the fibers are heated to above 85 ° C.

It there is a need for improvements in the PTT fiber process, in particular PTT staple fiber process in which fibers with suitable processing properties in commercial operations in which carding and Garnettvorgänge be applied. The solution of these problems, in the course of years for PET or PBT fibers often do not transfer to PTT fibers, which due to the special properties that underlies the chemistry of the PTT polymer.

In In practice, it has been shown in particular that in the case of fine fibers below about 3.6 dtex with these previously used methods no sufficiently high crimp, durability and / or Stability of crimping, especially for the textile finishing process, can be achieved.

task Therefore, the present invention is a process for production PTT fibers, preferably PTT staple fibers, with improved crimping to provide.

This is produced by the process according to the invention achieved by PTT fibers.

The inventive method relates to the preparation polytrimethylene terephthalate (PTT) fibers with improved crimping, characterized in that the stretching of the usual Melt spinning process produced PTT fibers at a temperature up to 70 ° C and the PTT fibers after drawing and no heat treatment before entering the crimping chamber subjected and in particular at a temperature below to held at 85 ° C, then in the crimping chamber heated up to 100 ° C and during the ripples are fixed.

Polytrimethylene terephthalate useful in the process of the invention and processes for its preparation have long been known. The preparation is carried out batchwise, continuously, etc. Further information on the production can be found for example in the U.S. Patents 5,015,789 and 6,277,289 . EP 0 998 440 . WO 98/57913 and in S. Schauhoff, "New Developments in the Production of Polytrimethylene Terephthalate, (New Developments in the Production of Polytrimethylene Terephthalate (PTT))", Man-Made Fiber Year Book (September 1996) ,

According to the invention Polytrimethylene terephthalates used which are commercially available. Such polytrimethylene terephthalates are described, for example, by E. I. du Pont de Nemours and Company, Wilmington, Delaware (trade name "Sonora"), and sold by Shell. For use in the invention Method is particularly suitable crystalline PTT.

The Polytrimethylene terephthalate used in the present invention is suitable, usually has an intrinsic viscosity (IV) from 0.60 deciliter / gram (dl / g) to 1.5 dl / g, preferably 0.70 dl / g to 1.4 dl / g, more preferably 0.80 dl / g to 1.2 dl / g and more preferably 0.90 dl / g to 1.1 dl / g (measured in 50:50 Phenol / 1,1,2,2-tetrachloroethane at 20 ° C).

In In the practice of the present invention are polytrimethylene terephthalate homopolymers as well Polytrimethylene terephthalate copolymers of polytrimethylene terephthalate and polyethylene terephthalate and / or polybutylene terephthalate. Especially advantageous are fibers containing at least 85 mol% of polytrimethylene terephthalate consist, preferably at least 90 mol%, more preferably at least 95 mol%.

The PTT fibers can be prepared by spinning the polymers into filaments, and then processing into fibers, drawing and curling the fibers, and optionally applying a leveling agent, relaxing the fibers (optionally while the leveling agent hardened) and optionally Antistatic agent is applied to the fibers. In the case of staple fiber production, the fibers are then cut and packed in bales.

The preparation of the PTT fibers according to the invention is carried out using conventional methods and equipment, as are preferred in the art in the context of polyester fibers. For example, numerous methods of spinning in US 3,816,486 . U.S. 4,639,347 . GB 1 254 826 and JP 11-189938 described.

The Spinning speed at PTT is preferably 600 meters per minute or more and is typically 1200 Meters per minute or less. The spinning temperature is typically 245 ° C to 285 ° C and preferred 250 ° C to 275 ° C. This is particularly preferred Melt spinning performed at about 260 ° C.

The Spinneret is a conventional spinneret of the type as used in conventional polyester, wherein Hole size, arrangement and number of the desired Depend on the fiber and the spin system.

The Quenching the spun from the melt in this way PTT filaments can be made in a conventional manner be used by air or other fluids, as they are in the art (e.g., nitrogen). It can Cross-flow, radial, asymmetric or other cooling methods be applied.

To Conventional spin finishes can be used for cooling be applied using standard methods.

The obtained PTT fiber filaments according to the invention, for clothing textiles (eg knitted and woven fabrics) Textiles) and for nonwovens typically a single filament titer from 0.88 dtex to 6.6 dtex, preferably 1.7 dtex to 3.6 dtex and more preferably about 2.4 dtex. Fibers with larger values can for non-textile applications, such as B. for fiber fillers, to be useful.

The PTT fiber filaments thus produced are for further processing initially stored in pots. However, it is also possible to process these directly.

To A preferred method is the melt-spun PTT fiber filaments recorded on a towbar cylinder and then composed of several tow cylinders and made of fiber filaments produces a big tow. After that, the Fiber cables are stretched using conventional methods, preferably at 10 to 110 m / min. The stretch ratios preferably from 1.25 to 4, and more preferably from 1.25 to 2.5. The stretching is cold, d. H. at a Temperature of up to 70 ° C, preferably up to 60 ° C, particularly preferably up to 50 ° C, in particular up to 40 ° C, most preferably between room temperature (20 ° C) and 40 ° C.

To the stretching is to be sure that the temperature of up to at 85 ° C, preferably up to 70 ° C, more preferably up to 60 ° C, in particular up to 40 ° C, not exceeded becomes. Preferably, the temperature after stretching is between room temperature (20 ° C) and up to 70 ° C, especially between Room temperature (20 ° C) and up to 60 ° C, especially preferably room temperature (20 ° C) and 60 ° C, and most preferably between room temperature (20 ° C) and 40 ° C.

In Alternatively, the fiber cable may be stretched and before entering the subsequent crimping chamber heated to at least 20 ° C, but on not more than the maximum temperature of up to 85 ° C, preferably up to 70 ° C, especially preferably up to 60 ° C, more preferably one Temperature in the range of 30 ° C to 60 ° C. Before and while drawing can be carried out using conventional Methods are applied one or more finishes.

One Another important feature is the crimp picking (Curling) K1, a measure of the filling the fiber that passes through a mechanical crimping process is taught. The crimp picking is an important one Property that both for the processing of fibers as well as the characteristics of textile and fiber filling products, especially from staple fibers, is of importance. In the rippling picture the springback property is measured on the fiber, as they transmit through the mechanical process of curling becomes. This has an effect on their handling features such as on the processing in the subsequent process steps.

wobei L_k die Länge der gekräuselten Stapelfaser im entspannten freiliegenden Zustand ist und L_v die Länge der gleichen, jedoch gestreckten Faser, d. h. die Faser liegt dann praktisch geradlinig ohne Kräuselung vor. Die Streckung erfolgt unter Anwendung der sogenannten Entkräuselungskraft. Diese wird in Vorversuchen mit Hilfe einer an das Kraft-Dehnungsdiagramm der jeweiligen Faser angelegten Tangente ermittelt.Circling in the context of the invention means the following ratio:

where L _{k is} the length of the crimped staple fiber in the relaxed, exposed state and L _{v is} the length of the same but stretched fiber, ie, the fiber is then practically straight without crimping. The stretching is carried out using the so-called Entkräuselungskraft. This is used in preliminary tests with the help of a force-extension slide determined gram of the respective fiber tangent.

The Fiber curling also influences the load behavior the three-dimensional structure. The fiber crimping can be two-dimensional or three-dimensional and become conventional produced using mechanical means or may be inherently structural Differences or compositional differences in the fiber to be available. Assuming a constant fiber weight, more similar Fiber size, geometry and surface properties As a rule, a fiber with low crimp (i.e. H. a high amplitude, low frequency of crimping) a higher volume retention (i.e., a highly efficient bulking, three-dimensional structure with low density, slightly under a given standard load due to a small amount the entanglement of the crimped fibers is deformed) produce. In contrast, fibers with higher produce Ripple (low amplitude, high frequency) in the Usually three-dimensional structures with higher density and reduced volume retention. Such three-dimensional structures higher density will not deform so easily, though a standard load is applied, indicating a higher level of Fiber entanglement in the structure is. In typical filled articles is the applied Load (that is, the load for which the article was dimensioned, to keep them) high enough to get a relative shift effect the fibers in the structure. This load is not big enough to cause plastic deformation of the individual fibers cause.

Of the Ripple also affects the assets the fiber to recover after compression. Fibers with low Ripples do not recover as easily as fibers with high crimping because of the fibers with little crimping the "suspension" is missing, the higher one Crimping is mediated. On the other hand, fibers are with slight curling easier to loosen what is on the lower amount of fiber entanglement is. The user of filled articles wishes typically both hold and volume. These both properties are strongly influenced by the crimp frequency, but in opposite and contradictory ways. Around To obtain a high volume content, one uses a low Crimp. The opposite one uses a high Rippling to get a strong hold. Further Variables that you can modify close the change the mechanical properties of the fiber, adjusting the Fiber diameter and / or a change in the fiber cross-section.

For the crimp of the fibers stretched as described above can conventional methods of mechanical crimping be applied with known crimping machines. A mechanical device for staple fiber crimping is preferred with steam assist, such as a stuffer box.

Around the inventively improved puckering to obtain fine PTT fibers are the stretched fibers before entering the crimping chamber and initially also in the crimping chamber according to the invention below up to 85 ° C, preferably below to at 70 ° C, more preferably below up to 60 ° C, especially below up to 40 ° C, most preferably between room temperature and 40 ° C held. The curling itself occurs in the crimping chamber by heating, preferably with steam, to below up to 100 ° C, preferred below up to 95 ° C, more preferably about 85 ° to 90 ° C.

Under Conventional methods can be used in the crimping device another finish can be applied.

The PTT fiber according to the invention preferably has a Crimping degree of at least 3 ripples (Curling arches) per cm, preferably 3 sheets per cm to 9.8 sheets per cm and more preferably 3.9 Bows per cm to 8.9 sheets per cm. For applications For the production of textile surfaces, values for the degree of crimping of about 5.5 sheets per cm particularly preferred, for fiber fillings the degree of crimping particularly preferably about 3.9 sheets per cm.

The Crimping K1 is preferably according to the invention 15% or more, preferably 17% or more.

Preferably, after smoothing and before relaxation, a smoothing agent is applied and / or a commercial lubricant is applied for further processing (converting). Exemplary smoothing agents useful in the present invention are disclosed in U.S. Pat US 4,725,635 described.

Optional can on the filaments after relaxing other textile equipment, z. As an antistatic equipment applied.

Farther If desired, the fibers can be prepared without pillars become.

To make staple fibers, the textured fibers are taken up, followed by cutting and packaging in bales. The staple fibers of the present invention are preferably cut on a relaxation downstream mechanical cutter. Become cable types uncut packed in bales and fed to a separate cutting process (converting).

The Staple fibers can be fixed before cutting. The Main fixing takes place according to the invention in the Crimping chamber by introducing superheated steam by means of conventional Devices. After that, before cutting at about 90 ° C be postfixed to 120 ° C, to ripple and Control shrinkage. Methods for fixing and the times used can vary and can be made using UV devices seconds or when using a furnace even longer. Oven temperatures are 80 ° to 130 ° C, preferably 100 ° C to 120 ° C, more preferably 110 ° C to 115 ° C.

Another The invention relates to the use of the invention Fiber products in textile fabrics, such. B. tissues, Nonwovens or fiber fabrics, as well as for fiber fillers.

The The invention will be explained in more detail with reference to the following example:

Example:

dry PTT granules (residual moisture <10 ppm, Drying at a maximum of 130 ° C) with a viscosity of IV = 0.92 (20 ° C, 50:50 phenol / 1,1,2,2-tetrachloroethane) is melted in an extruder, through a spinneret spun with 400-1200 holes and the obtained Thread group deducted in the range of 900-1200 m / min and stored in sliver cans.

Around the desired target cable strength of 90 ktex to reach a fiber titer of 2.4 dtex after drawing, the tow is presented at the sliver line. During further processing, especially during and after drawing, that will Fiber cable until reaching the stuffer box crimping machine not exposed to temperatures higher than 30 ° C. In the Crimp itself is the material by introducing Hot steam fixed in curled form. The choice of Chamber and roller pressure depends on the desired Crimping off. In one variant takes place on the last Roller septet in front of the crimping a supporting Preheating the cable at 30-60 ° C.

To the crimping is a Nachfixierung at 90-120 ° C. The choice of temperature depends on the desired Residual shrinkage (measured as thermal shrinkage at 200 ° C) Fiber off.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - GB 1254826 [0004, 0022]
• - EP 1016741 [0005]
• - JP 11-107081 [0006]
• - JP 11-189938 [0007, 0022]
• - US 3584103 [0008]
• - EP 1230450 [0009, 0011]
• - EP 1230451 [0010, 0011]
• - US 5015789 [0017]
• US 6277289 [0017]
• EP 0998440 [0017]
• WO 98/57913 [0017]
• US 3816486 [0022]
• US 4639347 [0022]
• US 4725635 [0041]

Cited non-patent literature

• - S. Schauhoff, "New Developments in the Production of Polytrimethylene Terephthalate, (New Developments in the Production of Polytrimethylene Terephthalate (PTT))", Man-Made Fiber Year Book (September 1996) [0017]

Claims (14)

A process for the preparation of polytrimethylene terephthalate (PTT) fibers with improved crimping, characterized in that the stretching of the PTT fibers produced by conventional melt spinning processes is carried out at a temperature of up to 70 ° C and the fibers after drawing and before entering the Crimping chamber subjected to no heat treatment and in particular be maintained at a temperature below up to 85 ° C, then heated in the crimping chamber up to 100 ° C and fixed during the crimping still in the crimping chamber. Process according to claim 1, characterized characterized in that the temperature during the drawing up to 60 ° C and after drawing up to 70 ° C is. A method according to claim 1 or 2, characterized in that the temperature before entering in the crimping chamber up to 70 ° C, preferably up to 60 ° C, more preferably between room temperature and 40 ° C, then in the crimping chamber up to 95 ° C, preferably Heated to 85 ° to 90 ° C and then by Introducing hot steam is fixed. A method according to claim 1 or 2, characterized in that the fibers before entering the Crimping chamber at least 20 ° C over the Temperature to be preheated after stretching, however to not more than 85 ° C. Method according to one of the preceding claims, characterized in that the fibers before entering the Crimping chamber at least 20 ° C opposite the temperature to be preheated after stretching, but not more than 70 ° C, preferably not more than up to 60 ° C, more preferably between 30 and 60 ° C. Method according to one of the preceding claims, characterized in that the heating in the crimping chamber with water vapor. Method according to one of the preceding claims, characterized in that the PTT fiber filaments have a single filament denier from 0.88 dtex to 6.6 dtex, preferably 1.7 dtex to 3.6 dtex and most preferably about 2.4 dtex. Method according to one of the preceding claims, characterized in that the degree of crimping at least 3 sheets per cm, preferably in the range of 3 sheets per cm to 9.8 sheets per cm, and most preferably in Range from 3.9 sheets per cm to 8.9 sheets per cm, is. Method according to one of the preceding claims, characterized in that the degree of crimp 5.5 bows per cm. Method according to one of the preceding claims, characterized in that the crimping of the fibers at least 15%, preferably at least 17%. Method according to one of the preceding claims, characterized in that the PTT fibers cut after fixation and are present as staple fibers. PTT fibers with improved crimping made according to one of the preceding claims claimed method. Use of the fibers according to claim 12 for the production of yarns or textile products, in particular for the manufacture of knitwear and woven textiles, preferred for the clothing industry, as well as for Nonwovens. Use of the fibers according to a of claims 1 to 8 for the production of filling fibers for filling covers, in particular pillows, quilts and quilts, and for mattresses, sleeping bags, Insulating material and upholstery.