DE19915683A1 - Polyester fibers and filaments and process for their manufacture - Google Patents

Abstract

The invention relates to fibres or filaments consisting mainly of polyethylene terephthalate as a fibrous polymer, containing 0.1 to 4 wt. % in relation to said fibrous polymer of a polyamide from the following group: polyepsiloncaprolactam, polyamide 12 and amorphous polyamide 6I/6T; mainly in the form of intercalations. The polyamides have a relative viscosity in certain areas and the polyepsiloncaprolactam has a particle size of less than 3 mu m in the melt. 0.02 to 1.0 wt. % of an organic phosphorous stabiliser selected from the class of phosphonic compounds is also provided in the polymer mixture for preventing yellowing. The winding speed for the filaments is up to 8000m/min. for producing partially oriented yarns. The invention also relates to a method for producing novel polyester fibres and filaments.

Description

The present invention relates to polyester fibers and filaments, which in have small amounts of other additives and a process for their preparation.

It is known that fibers or filaments, which contain small amounts of additives included, depending on the composition of the mixture, processed using melt spinning and partly an increase in the elongation at break in the same pull-off speed can produce undrawn yarn. For example, in EP 0 041 327 B1 Mixtures of polyester with liquid crystalline substances (LC polymers) described. Such liquid crystalline admixtures, however, are expensive and cause problems in the Spinning with yourself. In addition, there are irregularities in the yarn and broken threads expected.

EP 0 080 274 B1 describes the admixture of polyhexamethylene adipamide and Polyethylene glycol to the fiber-forming polymer (polyethylene terephthalate). This brings an increase in the elongation at break. The spinning of such mixtures is designed however problematic. So thread breaks often occur, as from the below Tables 1 and 2 can be seen (see additive types A52503, A3 and A4). In EP 0 080 274 B1 generally mentions that in addition to polyolefins, such as polyethylene, Polypropylene and polyethylene glycol also include polyepsiloncaproamide in principle Polyethylene terephthalate belongs to immiscible polymers. According to the examples and in but only polyhexamethylene adipamide meets the requirements in addition to polyethylene glycol Additional polymer before, which means for the expert that polyamide 6 in the rest Requirements such as spinning behavior and product properties apparently clearly worse cut off as polyamide 66 and was therefore not pursued as an additive.  

The term "immiscible polymer" is used in connection with the present Application understood such a polymer that a two-phase at spinning temperature Melt forms with the fiber-forming thermoplastic polymer. Microscopic Investigations of such a melt or photographic recordings show one two-phase system in which finely divided drops of the immiscible polymer are continuously dispersed in the fiber-forming polymer matrix.

The state described above in which the immiscible polymer is in the fiber-forming polymer matrix is fundamentally different from the formation a so-called anisotropic melt in the temperature range at which the thermoplastic polymer can be melt-spun. These anisotropic conditions can be created by liquid crystalline substances such as. B. in EP 0 041 327 are described, polyester spun polymers are added and heated and the Conditions set by the action of shear forces.

Aslan et al. in J.Appl.Polym.Sci., Vol. 55, 57-67 (1995) describe the spinning of Mixtures of polyethylene terephthalate and nylon 6. There were spinning speeds investigated up to 3600 m / min at a concentration of 5 wt .-% polyamide 6. Here there was a reduction in the elongation at break compared to the unmodified one Comparative material.

Evstatiev et al. in J.Appl.Polym.Sci., Vol. 67, 723-737 (1998) examined molecular Interactions in PET / PA6 alloys with a weight ratio of 40/60 µm find out the compatibility of such alloys. A ratio of 60% PA6 in polyester makes such a fiber absolutely uneconomical.

Various Japanese publications published by Aslan et al. were quoted and which are for technological background are expected to deal with the mixture of polyester and polyamide. J 61266616-A (as a Derwent abstract) describes an elimination of the Fibrillation of polyester / polyamide mixtures at high concentration ratios, J 56015414-A (as a Derwent abstract) the admixture of 10 to 30% polyester to nylon 6.  

EP 00 47 464 B1 describes various acrylic polymers as additives, including especially as a polymeric additive for polyethylene terephthalate (PET) Polymethacrylic acid methyl ester highlighted.

As can be seen from EP 00 47 464 B1 and EP 0 631 638 B1 - in the latter document there is a analog imidized additive described - the spinning security is limited here. It comes with the use of this material increasingly thread breaks.

EP 0 631 638 B1 describes a fiber polymer which contains 0.1 to 5% by weight, based on the fiber polymer, a 50 to 90% imidized polymethacrylic acid alkyl ester, im essentially in the form of inclusions. This fiber polymer shows in comparison an improved spinning behavior to that described in EP 0 047 464 B1, although none Numerical examples can be given in this regard. A major disadvantage of Polymethacrylic acid alkyl ester additives are the relatively high price of the additive. In particular, the cost of the imidized polymethacrylic acid alkyl ester shows that the The economics of a process that requires the additive mentioned are not given. In addition, the additive described is not available on a large scale and it there is also a dependency on a few manufacturers.

In addition, neither is the production of a direct and for the stretch texturing process partially oriented yarns that are suitable without problems and their further processing in EP 0 631 638 B1 documented with examples. So elongation at break values become Spinning speeds of 3500, 6000, 7000 and 8000 m / min are specified. This is about but it is not a question of elongation values, which are required for further processing in the texturing process are needed with advantage. For example, at a spinning speed of 6000 m / min given an elongation at break value of 65%. A yarn with one However, stretch is not easy to use in the stretch texturing process and is rather unusual. In contrast, stretch values common for the stretch texturing process are around 120%. The refer to the specified elongations at spinning speeds of more than 3500 m / min  on a highly oriented yarn for technical and textile use.

According to the information in EP 0 530 652 B1, from a spinning speed of 6000 m / min a special spinning device is required. Accordingly, a perforated tube is used below the nozzle, which delays cooling and stabilizes the spinning process. A such method, which is based on passive cooling by air intake due to the Filament movement is predestined for more critical spinning processes. The essential A disadvantage of the described device is, in particular, the associated one lack of or limited flexibility of the spinning process.

The examples of EP 0 530 652 B1 also describe the very important one Surprisingly, the spinning speed range of 4000 to 6000 m / min was not appreciated. However, this is precisely the area in which spinning crystallization clearly begins and that would be very interesting. In this speed range, according to those there Specifications worked with a cross-flow blowing. Now, surprisingly, this is very important speed range not described and at higher speeds a passive cooling technique is used, which is excellent for the more critical Speeds and / or critical melt-spinnable polymers is suitable can be assumed that possibly even at spinning speeds of less than 6000 m / min disturbances in the spinning process can occur. In this case it is Cross-flow blowing can only be used to a limited extent for the polymer mixture described and the the entire process is clearly limited.

The prior art thus describes a limited number of polymer mixtures, which can be suitable for the production of fibers with increased elongation at break. A However, acceptable spinnability of the alloys would at most be within the scope of EP 0 631 638 B1 given; To ensure good spinnability, there is a certain Spinning speed additionally requires a special spinning device (see EP 0 530 652 B1).

Mixtures of polyester with polyhexamethylene adipamide (EP 0 080 274) are used in  Connection with EP 0 631 638 not described in the prior art.

In addition, that described by the inventors of The present application recognized the problem that when mixing polyamides with Polyethylene terephthalate in the melt a more or less strong yellow discoloration occurs. The products spun from it are due to this yellowing of the Processors are not accepted and must therefore be discarded as unusable.

The object of the present invention is to provide polymer mixtures for the production of To provide polyester fibers and filaments that are easily spinnable and clear Contain less than 5% polyamides as additives, the manufacturing process by small amount added, good availability of the additive and strong Increasing the elongation at break should have a high cost-effectiveness, and also the Yellowing is reduced or eliminated so that the products are placed in the market to let.

This object is achieved by the fibers and the filaments according to claim 1 and by Method according to claim 12 solved.

Advantageous embodiments of the invention are contained in the subclaims.

Surprisingly, it has been shown that polymer mixtures made of poly ethylene terephthalate and small amounts of polyepsiloncaprolactam (polyamide 6), Very high polyamide 12 or polyamide 6I / 6T fibers and filaments Elongation at break can produce especially at high spinning speeds and show excellent spinning behavior at the same time. Alloys Polyethylene terephthalate and polyamide 6 are known, but they increase the elongation at break Effect combined with excellent spinning behavior is new. Beside that Surprisingly, even with relatively low additive concentrations, elongation values achieved, which is very good for the further processing of the filaments in the stretch texturing process are suitable. Such an effect has so far been complete for polyamide 12 and polyamide 6I / 6T unknown.  

As a further feature essential to the invention, these polymer blends contain one organic phosphorus stabilizer from the class of the phosphonic compounds. So that can Surprisingly, yellow discoloration can be largely suppressed.

The polymer mixtures used according to the invention can also be used at high Spinning speeds without any problems using conventional cross-flow blowing be spun.

However, other known cooling devices such as, for. B. Devices for passive cooling by air intake of the high-speed threads or Blowers arranged in the center of the bundle of threads.

It was not previously known that using polyethylene terephthalate / polyamide 6-, Polyethylene terephthalate / polyamide 12- and polyethylene terephthalate / polyamide 6I / 6T- Blends tremendous productivity gains through increasing the elongation at break high spinning speeds are possible, surprisingly at the same time, despite the high elongation, excellent spinnability of the mixture was observed. In addition, polyamide 6 and polyamide 6I / 6T are in particular compared to that in EP 0 631 638 B1 described additive component (polymethacrylic acid alkyl ester) clearly cheaper and more readily available.

In particular the commercially available polyamide 6 products from EMS-CHEMIE AG, CH-7013 Domat / Ems (Switzerland), especially the types Grilon® F34, F40, F47 and F50 turned out to be an advantageous additive. The types with are particularly preferred a relative viscosity in the range from 2.5 to 5.2, measured 1% in concentrated Sulfuric acid at 20 ° C. These produce a large increase in the elongation at break.

Relative to the elongation effect is the relative viscosity of the additive Polyamide 6 is not critical in large areas. Usually one is in this regard  Range of 2.5 to 5.2 preferred. In view of the very good at the same time Spinning behavior, relative viscosities of 2.8 to 4.1 have been found to be very suitable exposed. Relative viscosities in the range from 2.8 to 3.7 are particularly suitable.

The commercially available Grilamid® from is particularly preferred as a polyamide 12 additive Type L20 from EMS-CHEMIE AG, its relative viscosity, measured 0.5% in m-cresol at 20 ° C, in the range of 1.85 to 1.95. Generally suitable is polyamide 12 with a relative viscosity in the range of 1.6 to 2.3. The range from 1.8 to 2.0 is preferred.

The third type of polyamide, polyamide 6I / 6T, is a partially aromatic copolyamide that is constructed according to its nomenclature from the monomers hexamethylenediamine, Isophthalic acid and terephthalic acid. For the use according to the invention Surprisingly it was shown that from the variable composition range (ratio the amount of isophthalic acid to terephthalic acid), that polyamide 6I / 6T class good results brings that has an amorphous structure. Of these, those are preferred, which one have relative viscosity in the lower range, which in view of the reverse statement in State of the art on nylon additives in PET was completely unexpected (cf. EP 0 080 274 B1, Page 9, Example 8, lines 30 and 31). A relative viscosity, measured at 0.5%, is suitable in m-cresol at 20 ° C, maximum 1.50. The range from 1.35 to 1.45 is preferred. The corresponding commercial product Grivory® type G16 is particularly suitable EMS-CHEMIE AG, which with an isophthalic acid to terephthalic acid ratio of 70:30 is amorphous and has a relative viscosity of approximately 1.42.

To stabilize the polymer mixtures against yellowing, the following group of Preferred phosphonic compounds: 2-phosphonopropionic acid (= 2-carboxyethanephosphon acid), Ethoxycarbonyl-Methanphosphonsäurediethylester and Irganox® 1222. Because this Compounds can lower the molecular weight of the polyester, they will advantageously added during the polycondensation of the polyester. The addition less Quantities are also possible together with the polyamide additive.

The concentration of the phosphonic compounds is for the use according to the invention in the range of 0.02 to 1.0% by weight. The range from 0.05 to 0.6% by weight is preferred. chosen.  

The admixture of the polyamide additives to the polyethylene terephthalate can, for example via the so-called "melt conditioning" process for the continuous modification of Polymer melts take place (DE 40 39 857 C2). The disclosure content of DE 40 39 857 C2 is hereby fully made the content of this application. There becomes part of the Melt branched off from the main melt stream. This partial flow is divided into one Side stream extruder fed and there with the additive, which in granules, pearl or preferably in powder form, applied and then dispersed. That dispersed and mixed melt concentrate is then fed back into the main melt line and diluted there to the final concentration.

Instead of the "melt conditioning" method, it is also possible, for example, by means of of a melt extruder to produce a pure additive melt and in the To inject the main melt stream. A corresponding arrangement of mixing elements ensures then for homogenization and dispersion of the additive in the matrix polymer (Polyethylene terephthalate = PET).

In the case when starting from PET granulate and this in a spinning extruder is melted, it is also possible to add the additive directly to the PET granulate Meter in the spinning extruder and disperse the additive in the polyethylene terephthalate and then spin the melt mixture. For the purpose of good dispersion in this case too, the powder form of the additive is preferred.

The additive can be added both as a pure substance and in masterbatch form. In addition, other additives (e.g. stabilizer according to the invention) incorporated and spun with. The polyethylene terephthalate itself can already the usual additives such as matting agents (titanium dioxide), stabilizers (in particular contain the necessary) catalysts, etc. In the context of this Registration is understood as "polyethylene terephthalate" (PET) or "polyester" Polyesters containing at least 80% polyethylene terephthalate and 20% units, derived from a diol other than ethylene glycol such as diethylene glycol, Tetramethylene glycol or an acid other than terephthalic acid, for example  Isophthalic acid, hexahydroterephthalic acid, dibenzoic acid.

You can optionally polyethylene terephthalate with small molar amounts Branching agent with 3 to 4 functional alcohol or acid groups, Trimethylpropane, trimethylolethane, pentaerythritol, glycerin, trimesic acid, trimellitic acid or modify pyromellitic acid.

The starting polyester can also contain known additives to increase the ability of the to modify reactive coloring, such as B. Sodium 3,5-dicarboxybenzenesulfonate.

In the melt line z. B. the possibility of further dynamic and / or static To use a mixer. Dynamic and / or static mixers can also be used directly in front of this be placed on the spin pack.

It is particularly noteworthy that those investigated in the examples according to the invention Polyamide 6 drop sizes in the polyethylene terephthalate matrix is 250 to 400 nm, d. H. less than 0.5 µm. Those described in the context of the document EP 0 080 274 B1 In contrast, droplet sizes (particle sizes) are between 0.5 and 3 µm. It can therefore can be assumed that with very finely distributed drops in the matrix a relative seen better spinning behavior of the polymer mixture than in the case of larger Deposits, which are already due to their size, with the same concentration, in are located at a larger relative distance from each other and thus a less homogeneous Distribution. The particle size was determined on samples from the still unspun melt mixture where the particles were still spherical. All particles were below the specified upper limit of 0.5 µm.

The invention will now be explained in more detail with reference to the following examples, without the invention however, restrict it.  

Conventional spinning machines known to the person skilled in the art, such as e.g. B. described in Ullmann's Encyclopedia of Industrial Chemistry, Vol. 10, Fibers, 3. General Production Technology, page 535, Fig. 26.

example 1

Table 1 shows results from spinning tests at a winding speed (Vwick) from 4950 m / min. The spinning temperature was 292 ° C for PA6 and 295 ° C for Grilamid® L20 and Grivory® G16 and G21, the range from 280 ° C to 295 ° C being preferred. For Conventional cross-flow blowing was used to cool the filaments. After The yarn was passed through a cold godet duo by passing through the crossflow and then wound up. The godet or take-off speed, i. H. the actual spinning speed, was 5000 m / min in all variants. For the production the yarn became an ordinary, matted for textile use Polyethylene terephthalate from EMS-CHEMIE AG with the type designation M764 used. The additives used were polyepsiloncaprolactam with the Designations A23, F34, F40, F47, F50 from EMS-CHEMIE and Polyhexamethylene adipamide from BASF with the type designations AS2503, A3, A4 and A5. The additive was applied in powder form to the polyethylene terephthalate Granules rolled up. The concentration of additives PA6 and PA66 was 1.25 each Weight percent based on the polyethylene terephthalate. In the case of PA12 and PA6I / 6T it was 3% by weight.

The comparison of the different additives showed, especially when using A23, F34, F40, L20 and G16 a trouble-free, excellent spinning behavior, whereas in direct comparison when using polyhexamethylene adipamide for all types very much thread breaks were common. With the mixture of polyethylene terephthalate / A5 the thread broke every time during the lay-up process, so that no bobbins could be produced. When compared to the type G16, the more viscous type G21 showed no stretching effect.  

Example 2

The results in Table 2 were tested in a 6-strand production spinning station receive. Spinning temperature and winding speed (Vwick) were 288 ° C and 4950 m / min. The godet speed was in all variants except for the Zero test "Zero-2" 5000 m / min. With the variant "Zero-2" (conventional, without additives) the godet speed was 3225 m / min. The was used here "Melt conditioning" process, which is usually used for melt modification in continuous polyester-polycondensation plants with directly connected spinning mill is used. The additives F34, F40 and AS2503 were used Concentrations of 1.5 and 2 percent by weight. This was also evident unproblematic and trouble-free spinning behavior with types F34 and F40, whereas thread breaks often occurred when using AS2503. The size of the Polyamide 6 drops in the melt were 250 to 400 nm Place that type AS2503 of all polyhexamethylene adipamide types from example 1 still the best in relative terms, but showed poor running behavior.

Table 3 shows textile data of the textile yarn. The one with the modified polyester The quality data achieved correspond to that of good, conventionally produced Texture yarn. The benefit lies in the enormous productivity increase in the spinning mill, if you consider that normal POY yarn is only spun at approx. 3200 m / min.

Also in the production of fibers (staple fibers) results in a gain in productivity, wherein melt-spun much slower in this case, it is then stretched much stronger (as the skilled worker from Ullmann's Encyclopedia of Industrial Chemistry, 5 ^th Ed., Vol. A10, Fibers, 3 General Production Technology, pages 550 to 561). The increase in productivity in fiber production manifests itself above all in a significantly increased draw ratio on the fiber line, in addition to the correspondingly higher throughput in melt spinning.

Legend for tables 1 to 3

The abbreviations in Tables 1 to 3 have the following meanings

Table 3 (stretch texturing)

Claims (19)

1. Fibers and filaments consisting essentially of polyethylene terephthalate as the fiber or filament-forming polymer, polyamide as the additional polymer, and at least one stabilizer, characterized in that the fibers and filaments, based on the fiber polymer, 0.1 to 4% by weight, Contain polyamide, mainly in the form of inclusions, and the polyamide is selected from the group consisting of polyepsiloncaprolactam, polyamide 12 and amorphous polyamide 6I / 6T, the polyepsiloncaprolactam having a particle size of less than 3 μm in the melt and a relative viscosity, measured 1% in concentrated sulfuric acid, in the range from 2.5 to 5.2, the relative viscosity of the polyamide 12, measured 0.5% in m-cresol, is in the range from 1.6 to 2.3 and the relative viscosity of the Amorphous polyamide 6I / 6T, measured 0.5% in m-cresol, is a maximum of 1.50, and in the polymer mixture intended for melt spinning at least one organic phosphorus stabilizer in one r amount of 0.02 to 1.0 wt .-% is included, selected from the class of phosphonic compounds, and wherein for the production of partially oriented yarns the winding speed for the filaments is up to 8000 m / min. 2. Fibers or filaments according to claim 1, characterized in that the Phosphonic compound is selected from the group consisting of 2-phosphonopropionic acid, Ethoxycarbonyl-methanephosphonic acid diethyl ester and Irganox® 1222. 3. Fibers or filaments according to claim 1 or claim 2, characterized in that the phosphonic compound in an amount of 0.05 to 0.6 wt .-% in the  Polymer mixture is included. 4. Fibers or filaments according to one or more of the preceding claims 1 to 3, characterized in that the polyamide in an amount of 0.5 to 3 wt .-%, based on the fiber polymer is added. 5. Fibers or filaments according to one or more of the preceding claims 1 to 4, characterized in that the relative viscosity in the case of Polyepsiloncaprolactam in the range from 2.8 to 4.1, measured 1% in concentrated Sulfuric acid. 6. Fibers or filaments according to claim 5, characterized in that the relative Viscosity of the polyepsiloncaprolactam is in the range from 2.8 to 3.7. 7. Fibers or filaments according to one or more of the preceding claims 1 to 6, characterized in that in the case of polyepsiloncaprolactam Particle size in the melt is less than 1 µm. 8. Fibers or filaments according to claim 7, characterized in that the Polyepsiloncaprolactam a particle size of less than 0.5 microns in the melt having. 9. Fibers or filaments according to one or more of the preceding claims 1 to 4, characterized in that the relative viscosity in the case of polyamide 12 is in the range from 1.8 to 2.0, measured 0.5% in m-cresol. 10. Fibers or filaments according to claim 9, characterized in that the relative Viscosity of the polyamide 12 is in the range of 1.85 to 1.95. 11. Fibers or filaments according to one or more of the preceding claims 1 to 4, characterized in that the relative viscosity in the case of amorphous Polyamide 6I / 6T is in the range from 1.35 to 1.45, measured 0.5% in m-cresol.   12. Process for the production of essentially from polyethylene terephthalate existing melt-spun fibers and filaments through polycondensation or melting the polyester fiber polymer and then Melt spinning, characterized in that the fiber polymer before Melt spinning 0.1 to 4% by weight, based on the fiber polymer, of a polyamide from the group polyepsiloncaprolactam, polyamide 12 and amorphous polyamide 6I / 6T and a stabilizer from the class of the phosphonic compounds in an amount of 0.02 to 1.0% by weight and, if appropriate, further additives are added, wherein the polyepsiloncaprolactam in a relative viscosity, measured 1% in concentrated sulfuric acid, from 2.5 to 5.2, the polyamide 12 in a relative Viscosity, measured 0.5% in m-cresol, from 1.6 to 2.3 and the amorphous Polyamide 6I / 6T in a relative viscosity, measured 0.5% in m-cresol, of a maximum of 1.50 is used, in the case of polyepsiloncaprolactam Dispersion takes place in the melt down to a particle size of less than 3 µm, and wherein for the production of partially oriented yarns Winding speed for the filaments is set up to 8000 m / min. 13. The method according to claim 12, characterized in that one as a fiber polymer Selects polyethylene terephthalate. 14. The method according to claim 12 or 13, characterized in that the Fiber polymers 0.5 to 3 wt .-% polyamide are added. 15. The method according to one or more of claims 12 to 14, characterized characterized in that the phosphonic compound is selected from the group of 2- Phosphonopropionic acid, Ethoxycarbonyl-Methanphosphonsäurediethylester and Irganox® 1222, and that the phosphonic compound in the fiber polymer in the Polycondensation or is added together with the polyamide. 16. The method according to one or more of claims 12 to 15, characterized characterized in that one for the continuous modification of the polyethylene terephthalate melt part of the melt from the main melt stream  branches, feeds this partial stream into a side stream extruder, there with the Polyamide and optionally the stabilizer and / or other additives acted upon and dispersed therein, the dispersed and mixed Leads melt concentrate from the side stream back into the main melt line, there diluted to the final concentration and then the melt mixture spins. 17. The method according to one or more of claims 12 to 15, characterized characterized in that an additive melt by means of a melt extruder consisting of the polyamide and optionally other additives and this is injected into the main melt stream of polyethylene terephthalate, afterwards homogenized with the aid of a mixing device and dispersed in the matrix polymer and then spinning the melt mixture. 18. The method according to one or more of claims 12 to 15, characterized characterized in that it started from polyethylene terephthalate granules and this in a melt extruder is melted, and that the polyamide and optionally other additives directly to the polyethylene terephthalate granules in the Spinning extruder metered in and dispersed there in polyethylene terephthalate, and the melt mixture is then spun. 19. The method according to claim 16 or claim 18, characterized in that the Polyamide is added in powder form.