EP0987353A1 - Polyester fibres and filaments and process for their production - Google Patents

Abstract

Polyethylene terephthalate contains 0.1-4 wt.% small rod shaped inclusions of polymethyl methacrylate (PMMA) with Mw = 2 x 10<4>-2 x 10<5>. The fibres and filaments are produced with a draw off speed ≤ 8000 m/minute. Polyethylene terephthalate (PET) fibres and filaments, produced with a draw off speed ≤ 8000 m/minute from PET containing 0.1-4 wt.% polymethyl methacrylate (PMMA) with a weight average molecular weight (Mw) = 2 x 10<4>-2 x 10<5> in the form of small rod shaped inclusions with a lateral particle size 800 nm (measured in extruded, unoriented filaments). An Independent claim is also included for production of PET fibres and filaments by polycondensation of or melting and then melt spinning PMMA modified PET to form unoriented filaments, with the PMMA inclusions.

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 contain, depending on the composition of the mixture, processed using melt spinning and sometimes an increase in the elongation at break in the same pull-off speed can produce undrawn yarn.

EP 0 047 464 B1 shows that polymethyl methacrylate (hereinafter briefly Called PMMA) in principle to increase the elongation at break at higher spinning speeds can be used.

This document describes the use of melt-mixed, re-granulated Material consisting of polyester with the addition of polymethyl methacrylate described. At This approach is the most optimal type of premix to achieve of a homogeneous product. But as can be seen from EP 0 047 464 B1, comes it when using polymethyl methacrylates with high molecular weights Additive for problems in the spinning process (see page 5, lines 11 to 13).

EP 0 631 638 B1, like EP 0 047 464 B1, describes that polymethyl methacrylate is a has limited spinnability. EP 0 631 638 B1 describes a fiber polymer, which 0.1 to 5% by weight, based on the fiber polymer, imidized one to 50 to 90% Contains polymethacrylic acid alkyl esters, essentially in the form of inclusions. A major disadvantage of imidized polymethacrylic acid alkyl ester additives but is that relatively high price of the additive. The cost of the imidized polymethacrylic acid alkyl ester show that the economics of a process that does Additive needed, is not given. In addition, the additive described is not in available on a large scale, and it is also dependent on a few manufacturers given. Another disadvantage, as described above, is that the spinning security is limited. The use of this material as an additive is increasing Thread breaks.

The molecular weights described in EP 0 047 464 B1 are a maximum of 16,000 g / mol (see page 9, table 5). In addition, this document mentions that PMMA drop diameters in the polyester matrix of more than one µm the increase in elongation is no longer optimal. Otherwise, the morphology of the inclusions does not go further received.

Usually, as in EP 0 047 464 B1 and in "HP5, The Highly Economical POY Process for Polyester, Fiber Producer Conference, Greenville, 1998 " such incompatible deposits in the unoriented polyester vault, i.e. in from the Spinneret extruded unoriented melt thread, in the form of balls or drops In EP 0 047 464 B1, on page 4, lines 13 to 15, and on page 5, lines 8 and 9, indicated that the inclusions may (similar to a ball bearing) one Cause "roll effect" in the direction of the thread, which leads to a delayed deformation of the Polyester leads.

A possible connection of special shapes and sizes of additive storage in the still unoriented polyester vaults to the special properties required here End product and essential for an industrial process In contrast, spinning behavior was not recognized.

The object of the present invention is therefore to produce polymer blends of polyester fibers and filaments that are easily spinnable and not available contain more than 4 (% by weight of additive, the manufacturing process due to the low Amount, a wide availability of the additive and by a strong increase in Elongation at break should be highly economical.

This object is achieved by the fibers and the filaments according to claim 1 and by Method according to claim 8 solved.

Advantageous embodiments of the invention are contained in the subclaims.

Surprisingly, it has been found that polymer blends made of polyester, i.e. in particular Polyethylene terephthalate (PET) and small amounts of polymethyl methacrylate (PMMA) fibers or filaments that can be produced have very high elongations at break especially at high spinning speeds, can produce and at the same time show excellent spinning behavior. Mixtures of polyester, i.e. especially PET and Polymethyl methacrylate and the stretching effect of polymethyl methacrylate are known, but also known is the tendency to thread breaks when spinning the Mixture, which becomes even clearer when very high polymethyl methacrylate molecular weights be used.

Thus, as already mentioned in EP 0 047 464 B1, it is described that the increase in the Polymethyl methacrylate molecular weight increases the strain-increasing Produces effects, but also that spinning problems occur at the same time, i.e. the reinforced stretching effect at very high molecular weights of the polymethyl methacrylate can due to the associated tendency to increased thread breaks not come into play at all. The economy of an industrial process is therefore limited based on the product described in EP 0 047 464 B1.

Surprisingly, it has been shown that in the present invention, the still unoriented polyester vaulted additives, as in EP 0 047 464 B1 and in "HP5, The Highly Economical POY Process for Polyester, Fiber Producer Conference, Greenville, 1998 ", have a teardrop or spherical shape, but As can be seen in Figures 1, 2 and 3, a novel, rod-shaped or worm-like bring out stretched appearance. The invention is therefore based on the knowledge that that it is precisely these new characteristic structures of the PMMA deposits for improved Lead to spinnability, especially with very high polymethyl methacrylate molecular weights, as described in the example according to the invention.

It is also noteworthy that the lateral diameter of the novel rod-shaped Structures are very small. The rod-like inclusions shown in the example show for example, a lateral diameter of about 300 to 400 nm, measured in the still unoriented melt threads extruded from the spinneret, the so-called Vaults.

It is important that the diameter is less than 800 nm. A size of is preferred less than 600 nm, particularly preferably less than 400 nm.

The "rod-like" structure of the polymethyl methacrylate inclusions described within the present invention in the still unoriented polyester matrix the observations described in EP 0 047 464 B1 have nothing in common. The According to the present invention, "rod-shaped" structures must, as well always, a different compared to the principle described in BP 0 047 464 B1 Obey mechanism. The reason for this is very likely to be clear better running behavior in the context of the present invention.

It is conceivable that drops or spherical inclusions in a polyester matrix have an orientation-reducing effect, but also because of the here too expected molecular movements of the polyester matrix transverse to the thread propagation direction the spinning process is more or less disturbed.

In the case of the rod-like inclusions determined according to the invention for the first time the propagation components of the polyester molecules across the thread can be reduced, which is the Would explain improvement in spinning behavior.

The PMMA-containing polymer mixture 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 e.g. Devices for passive cooling by air intake of the high-speed threads or blowing devices, which are arranged in the center of the bundle of threads.

In general, the present invention is suitable both for the production of partially oriented yarns (POY) (as explained in the example), and for the production of fibers (ie staple fibers) in which spun (drawn off) much more slowly, but subsequently stretches much more (as is known to the person skilled in the art from Ullmann's Encyclopedia of Industrial Chemistry, 5 ^th Ed., Vol. A10, Fibers, 3. General Production Technology, pages 550 to 561). The economic gain in the present invention manifests itself in the case of fiber production above all in a significantly increased draw ratio on the fiber line, in addition to the correspondingly higher throughput in melt spinning.

In the manufacture of fibers with the present invention, one is preferably used Take-off speed selected in the range from 800 to 2,400 m / min during production of partially oriented filament yarns (POY) a take-off speed of 3,000 to 8,000 m / min.

The commercially available polymethyl methacrylate product has an additive DEGALAN® from DEGUSSA has proven to be advantageous. Despite the high molecular weight Type DEGALAN® G8E of 126,580 g / mol (weight average according to the following described measuring method), this has proven to be extremely suitable. The very high molecular material surprisingly brings in the mixture with polyester in addition to an enormous increase in elongation at high spinning speeds also one excellent spinnability with it. Because even the mixture of the very high molecular DEGALAN® G8E and polyethylene terephthalate (PET) excellent can also be assumed that the types with lower molecular weight (20,000 - 120,000 g / mol) as the used in comparison to the prior art also lead to improved spinning behavior.

In addition, polymethyl methacrylate is compared to that in EP 0 631 638 B1 described additive component (polymethyl methacrylimide) significantly cheaper and readily available.

With regard to the elongation effect, polymethyl methacrylate molecular weights are according to the invention (Weight average) between 20,000 and 200,000 g / mol. Molecular weights between 50,000 and 160,000 g / mol are preferred. All Molecular weights between 80,000 and 140,000 g / mol are particularly preferred.

The molecular weight information on the PMMA relates to the following measurement method (internal analysis specification No. LC 012 from EMS-CHEMIE AG):
The molecular weight distribution and the weight average (M _w ) of the molar mass of PMMA are determined by means of gel permeation chromatography (GPC), ie using a GPC measuring device with the basic pump, chromatography column and detector components known for liquid chromatography. A device from the WATERS company, type GPC 150A with IR detector, is used for the measurements. Four individual columns with dimensions of 250 mm x 7 mm (diameter) are connected in series as a column to a total column length of 1 m. The columns are filled with MERCK LiChrogel® 10 µm, in the combination PS4000, PS400, PS20 and PS4 (germinating for the pore size) for the four individual sections, so that each molecular weight fraction of the PMMA is optimally separated. Chloroform is used as the stock solution for the PMMA samples, with 0.1% 1,2-dichlorobenzene as the flow marker. Chloroform is used as eluent at a flow rate of 1 ml / min. For sample preparation, 50 mg PMMA are weighed into a closable 20 ml glass, filled up to the mark with stock solution and shaken until completely dissolved. At least 5 PMMA standards from the range 5,720 <M _w <360,000 g / mol, which are obtained from POLYMER LABORATORIES, are prepared in exactly the same way. The molecular weight measurement is calibrated with the standards. The injection volume of the sample solutions is 200 µl each. All temperature settings are at 30 ° C. The measurements (chromatograms) are evaluated using the GPC software MILLENIUM (from WATERS) according to the narrow standard method.

The amount of PMMA blended is in the range from 0.1 to 4% by weight, Based on the Polyester as a thread-forming polymer. The range from 0.2 to 3% by weight is preferred; an amount of PMMA in the range from 0.3 to 2% by weight is particularly preferred.

The admixture of the polymethyl methacrylate as an additive to PET can be, for example, about 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 that comes directly from a polycondensation or from a melt can, branched off from the main melt stream. This partial flow is divided into one Side stream extruder fed in and there with the additive, which is in granulate, Powder or preferably pearl shape, 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 into the main melt stream to inject. A corresponding arrangement of mixing elements then ensures for homogenization and dispersion of the additive in the thread-forming matrix polymer (Polyethylene terephthalate).

In the case when starting from PET granulate and this in a spinning extruder is melted, it is also possible to use the PMMA as an additive (in granulate, Powder or Pearl shape) directly into the PET granulate in the spinning extruder, there that Additive to disperse in polyethylene terephthalate and then the melt mixture to spin. This admixture variant is also like the "Melt Conditioning" process the initial form of PMMA is preferred as pearls because this is a fine distribution favored in the PET melt and also generally the PMMA commercial products are also available in this form anyway. These pearls can be called my beads imagine with a diameter of about 0.3 mm; they are sometimes used as semolina designated.

The additive can be added both as a pure substance and in masterbatch form. In addition, other additives or additives can also be incorporated and spun become. The polyethylene terephthalate itself can also contain the usual additives such as Contain matting agents (titanium dioxide), stabilizers, catalysts etc. in the The context of this application is understood as "polyethylene terephthalate" (PET) or "Polyester" means the polyester containing at least 80% polyethylene terephthalate units and contain a maximum of 20% units, derived from a diol other than ethylene glycol such as e.g. Diethylene glycol, tetramethylene glycol or a dicarboxylic 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, Trimethyloletane, pentaerythritol, glycerol, trimesic acid, trimellitic acid or pyromellitic acid, modify.

The starting polyester can also contain known additives to increase the ability of the Modify coloring, e.g. Sodium 3,5-dicarboxybenzenesulfonate.

In the melt line there is e.g. 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.

In a special embodiment of the invention, the dispersion is ready to use Melt mixture, according to any of the admixture variants described can be produced, initially not spun into threads, but granulated. This High-performance granules can later be used on conventional spinning machines with a melt extruder processed, i.e. to be spun into fibers or filaments. Here the processor, for example a customer of the granulate manufacturer, has all the advantages of the Polyester modified according to the invention, without this being his conventional Retrofit spinning machine with expensive dosing and mixing devices and a separate one Must buy additive. The whole handling is in this way for a processor as easy as with normal PET granules.

Figures 1, 2 and 3 show SEM cross-sectional images of an inventive Melt thread in the matrix polymer (PET), which is under the nozzle plate in the unoriented Condition was taken. In particular, from FIG. 3 ("chopsticks", cut on the side) the axial incorporation of the PMMA additive can be seen (extension in the thread axis).

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

Were used conventionally known to those skilled spinning machines, for example in Ullmann's Encyclopedia of Industrial Chemistry, ^5th Ed like them. Vol. A10, Fibers, 3. General Production Technology, page 535, Figure 26.

For example :

The results of the tests listed in Table 1 were obtained at a 6-strand production spinning station. Table 1 shows results from spinning tests at a winding speed (Vwick) of 4,950 m / min. The spinning temperature was 285 ° C, with the range of 280 ° C to 295 ° C being preferred. Passive cooling was used to cool the filaments, as described, for example, in DE 197 16 394 C1. After passing through the cooling section, the yarn was passed over a cold godet duo and then wound up. The godet or take-off speed, ie the actual spinning speed, was 5,000 m / min in all variants, except for the zero sample "zero-2". In the "Zero-2" variant (conventional, without additives), the godet speed was 3,225 m / min. The "melt conditioning" process (DE 40 39 857 C2) was used for the additive mixing, which is usually used for melt modification in continuous polyester-polycondensation plants with a directly connected spinning mill. A normal, matted polyethylene terephthalate from EMS-CHEMIE AG with the type designation Grilene® M764 was used to manufacture the yarns. The additive used was a polymethyl methacrylate from DEGUSSA with the type designation DEGALAN® G8E with a molecular weight of 126,580 g / mol (weight average). The concentration was 0.65 to 0.90 percent by weight. The mean lateral diameters of the polymethyl methacrylate inclusions (see Fig. 1, 2, 3) were less than 400 nm.
The spinning behavior was very good. Only full coils were produced.

Table 2 shows textile data of the textile yarn. The quality data achieved with the modified polyester correspond to that of good, conventionally produced texture yarn. The benefit lies in the enormous increase in productivity in the spinning mill, considering that normal POY yarn is only spun at around 3,200 m / min. 6-thread position of a production plant Add. Type G8E G8E G8E Zero-1 Zero-2 Quantity (%) 0.65 0.76 0.90 - - RD (%) 120.6 126.6 134.1 64.7 121.8 RF (cN / dtex) 2.4 2.24 2.01 3.07 2.31 Titer (dtex) 129.7 131.2 129.7 124.9 125.3 Vwick (m / min) 4950 4950 4950 4950 3170 Spinning behavior very good very good very good Good very good Diameter (nm) less than 400 less than 400 Stretch texturing Add. Type G8E G8E Zero-2 Quantity (%) 0.65 0.76 - RD (%) 21.3 21.7 21.4 RF (cN / dtex) 4.08 4.06 4.1 Titer (dtex) 80.7 77.1 75.8 Vtex (m / min) 800 800 800 Draw ratio 1.68 1.74 1,695 Running behavior very good very good very good

G8E =

PMMA-Typ der Firma DEGUSSA mit dem Handelsnamen DEGALAN® als Additiv in der angegebenen Menge dem PET zugesetzt.

Null-1 =

Nullvariante (Vergleichsbeispiel) ohne Additivzusatz, nur PET vom Typ Grilene® M764 der EMS-CHEMIE AG (relative Viskosität = 1,64 gemessen 1 %-ig in m-Kresol)

Null-2 =

wie Null-1, aber mit tieferer Spinn- und Aufwickelgeschwindigkeit

RD =

Reißdehnung

RF =

Reißfestigkeit

The abbreviations in Tables 1 and 2 have the following meanings:

G8E =

PMMA type from DEGUSSA with the trade name DEGALAN® added to the PET in the specified amount as an additive.

Zero-1 =

Zero variant (comparative example) without additive, only PET of the type Grilene® M764 from EMS-CHEMIE AG (relative viscosity = 1.64 measured 1% in m-cresol)

Zero-2 =

like zero-1, but with lower spinning and winding speed

RD =

Elongation at break

RF =

Tensile strength

Claims (18)

Fibers and filaments of predominantly polyethylene terephthalate as a thread-forming polymer, characterized in that they contain 0.1 to 4% by weight, based on the thread-forming polymer, of polymethyl methacrylate with a weight-average molecular weight of between 20,000 and 200,000 g / mol as another polymer, predominantly in Form of rod-shaped inclusions, measured in the still unoriented melt filaments extruded from the spinneret, the lateral particle size of the rod-shaped inclusions of the further polymer being less than 800 nm, and the speed at which the filaments are drawn off during production up to 8,000 m / min is. Fibers or filaments according to claim 1, characterized in that the rod-shaped polymethyl methacrylate inclusions have an average lateral diameter of less than 600 nm. Fibers or filaments according to claim 1, characterized in that the rod-shaped polymethyl methacrylate inclusions have an average lateral diameter of less than 400 nm. Fibers or filaments according to one of claims 1 to 3, characterized in that the polymethyl methacrylate has a weight average molecular weight of between 50,000 and 160,000 g / mol. Fibers or filaments according to one of claims 1 to 4, characterized in that the polymethyl methacrylate has a weight average molecular weight of between 80,000 and 140,000 g / mol. Fibers or filaments according to one of Claims 1 to 5, characterized in that they contain 0.2 to 3% by weight of polymethyl methacrylate. Fibers or filaments according to one of Claims 1 to 6, characterized in that they contain 0.3 to 2% by weight of polymethyl methacrylate. Process for the production of melt-spun fibers and filaments consisting essentially of polyethylene terephthalate by polycondensation or melting of the thread-forming polymer and subsequent melt spinning, characterized in that the thread-forming polymer comprises 0.1 to 4% by weight, based on the thread-forming polymer, of a polymer essentially polymethyl methacrylate with a weight-average molecular weight of between 20,000 and 200,000 g / mol are mixed and dispersed in before melt spinning and during melt spinning a take-off speed of the threads of up to 8,000 m / min is set, the dispersion in the spinning nozzle extruded, still unoriented melt threads rod-shaped inclusions of the PMMA with a lateral particle size of less than 800 nm can be obtained. Process according to Claim 8, characterized in that 0.2 to 3% by weight, based on the thread-forming polymer, of the polymethyl methacrylate is added to the thread-forming polymer. Process according to one of claims 8 or 9, characterized in that 0.3 to 2% by weight, based on the thread-forming polymer, of the polymethyl methacrylate is added to the thread-forming polymer. Method according to one or more of claims 8 to 10, characterized in that for the continuous modification of the polyethylene terephthalate melt, part of the melt is branched off from the main melt stream, this partial stream is fed into a side-stream extruder, charged with the polymethyl methacrylate there and dispersed therein, that dispersed and mixed melt concentrate from the side stream back into the main melt line, diluted there to the final concentration and then spun the melt mixture. Method according to one or more of claims 8 to 10, characterized in that a PMMA melt is produced by means of a melt extruder and this is injected into the main melt stream of polyethylene terephthalate, then homogenized with the aid of a mixing device and dispersed in the matrix polymer and then the melt mixture is spun becomes. Method according to one or more of claims 8 to 10, characterized in that starting from polyethylene terephthalate granules and melting them in a spinning extruder, and that the PMMA is metered directly into the polyethylene terephthalate granules in the spinning extruder and dispersed there in the polyethylene terephthalate, and one then the melt mixture spins. A method according to claim 11 or claim 13, characterized in that the polymethyl methacrylate is metered in in pearl form. Method according to one or more of claims 8 to 14, characterized in that further additives or additives are metered in simultaneously with the polymethyl methacrylate and admixed with the thread-forming polymer. Method according to one or more of claims 8 to 15, characterized in that the melt mixture dispersed ready for use is not immediately spun into filaments, but is first granulated and later processed on a spinning machine with a melt extruder. Method according to one or more of claims 8 to 16, characterized in that the withdrawal speed in the production of fibers is 800 to 2,400 m / min. Method according to one or more of claims 8 to 16, characterized in that the withdrawal speed in the production of partially oriented filament yarns is 3,000 to 8,000 m / min.

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