EP1287192B1 - Method for producing synthetic fibres from a fibre-forming polymer-based melt blend - Google Patents

Abstract

The present invention relates to a method for the manufacture of synthetic fibers from a melt mixture of fiber forming matrix polymers, wherein at least one second amorphous additive polymer, which is immiscible with the fiber forming matrix polymer, is added to the fiber forming matrix polymers in a quantity of 0.05-5 wt % (with reference to the total weight of fiber forming matrix polymer and the additive copolymer). The additive polymer is obtained by multiple initiation. Furthermore, the present invention also relates to the synthetic fibers produced by the method.

Description

The present invention relates to a process for producing synthetic filaments from a fiber-forming polymer-based mixture. The threads can on the one hand be used as continuous threads or else processed into staple fibers.

The spinning of polymer blends into synthetic filaments is already known. The aim is to obtain a higher elongation at break in the filament at a certain spinning speed than without modification by additional polymer. As a result, a higher draw ratio for the production of the final yarn should be possible, which should cause a higher productivity of the spinning unit.

The production increase aims to improve the profitability of the manufacturing process. This is being sidelined to some extent by production hurdles and more expensive high speed equipment. Significantly of influence are the additional costs for the additive polymer, so that there is even a zero point for the economy, depending on the amount added. The availability of additive polymers also plays an important role in the market. For these reasons, a large number of the additives described in the literature are ruled out for large-scale implementation.

The producer or procurer must take into account the entire production chain and can not stop increasing the production of a partial step (eg spinning). The follow-up processes must not be impaired.

In particular, it is a main object of this invention not to belittle, preferably to improve, the further processing conditions in the subsequent steps, and this despite increased spinning speed.

Thus, for example, for the production of POYs in the prior art for polymer blends very high elongation at break are also mentioned for high spinning speeds, which characterize a strong reduction of the degree of orientation. As is known, such filaments are not storage-stable and can not be applied and processed in draw-texturing processes at high speeds. Elongation at break <70% given at high spinning speeds in turn indicate a considerable degree of crystallization, which reduces the achievable strength in the texturing process.

The first approaches to solving these problems are described in documents EP 0 047 464 B (Teijin), DE 197 07 447 (Zimmer), DE 199 37 727 (Zimmer), DE 199 37 728 (Zimmer) and WO 99/07 927 (Degussa ) disclosed. EP 0 047 464 B relates to an undrawn polyester yarn, wherein by addition of 0.2-10% by weight of a polymer of the type - (- CH ₂ -CR ₁ R ₂ -) _n -, such as poly (4-methyl 1-pentene) or polymethyl methacrylate, improved productivity is achieved by increasing the elongation at break of the spun yarn at speeds between 2500-8000 m / min and correspondingly higher draw ratios. It is necessary to fine and uniform dispersion of the additive polymer by mixing, wherein the particle diameter ≤ 1 micron must be to prevent fibrillation. Decisive for the effect is the interaction of three properties - the chemical additive structure, which hardly allows any stretching of the additive molecules, the low mobility and the compatibility of polyester and additive. The measures serve to increase productivity. Requirements for draw texturing are not disclosed. The reworking of the technical teaching in the context of WO 99/07927 resulted in a high additive consumption and associated with a deterioration in quality and processability.

DE 197 07 447 (Zimmer) relates to the production of polyester or polyamide filaments having an elongation at break ≤ 180%. The addition of 0.05 to 5% by weight of a copolymer of 0 to 90% by weight of (meth) acrylic acid alkyl ester, 0 to 40% by weight of maleic acid (anhydride) and 5 to 85% by weight of styrene Polyester or polyamide allows a significant increase in spinning take-off speed.

The document DE 199 37 727 (Zimmer) discloses the production of polyester staple fibers from a polymer blend containing 0.1 to 2.0% by weight of an incompatible, amorphous, polymeric additive having a glass transition temperature in the range of 90 up to 170 ° C has. The ratio of the melt viscosity of the polymeric additive to the melt viscosity of the polyester component should be 1: 1 to 10: 1.

DE 199 37 728 (Zimmer) relates to a process for the production of polyester HMLS filaments, polymeric additive and optionally additives having a spinning take-off speed of 2500 to 4000 m / min. In this case, the polymeric additive should have a glass transition temperature in the range of 90 to 170 ° C and the ratio of the melt viscosity of the polymeric additive to the melt viscosity of the polyester component should be 1: 1 to 7: 1.

WO 99/07 927 relates to the production of POYs by spinning polymer blends based on polyester at a take-off speed v of at least 2500 m / min, wherein the polyester, a second, amorphous, melt-processable copolymer having a glass transition temperature of more than 100 ° C is added. The ratio of the melt viscosity of the copolymer to the melt viscosity of the polyester is 1: 1 to 10: 1. The polyester At least 0.05% by weight of copolymer is added and the maximum amount M of the copolymer added to the polyester depends on the take-off speed v and amounts to $$\mathrm{M}=[\frac{1}{1600}\cdot \mathrm{v}\left(\frac{\mathrm{m}}{\min }\right)-0.\mathrm{8th}][\mathrm{weight}\mathrm{,}-\%]\mathrm{,}$$

Although the latter methods (Zimmer AG) already show good and practical yarn breakage rates during the spinning of such polymer blends, the art nevertheless requires processes for spinning polymer blends with an even lower number of yarn breaks in order to further increase the efficiency of the spinning process. Furthermore, the Weiterverbeitungsverhalten the synthetic threads, especially in the stretch texturing should be improved.

In the case of the abovementioned processes, the elongation-enhancing agents used are usually granulated before being added to the polyester in order to increase the flowability of the additive polymer. However, due to its large grain size, the granulated additive polymer can only be metered relatively poorly and unevenly. This leads to a deterioration of the yarn characteristics, in particular the uniformity of the synthetic threads (eg staining behavior). In addition, since the granulation step of the strain enhancer is time consuming and costly, the application requires methods of melt spinning polymer blends which permit the use of non-granulated stretch enhancers.
The strain-increasing agents should be uniformly and continuously metered.

In view of the prior art, it was an object of the present invention to provide a process for the production of synthetic threads from a mixture based on fiber-forming matrix polymers, which allows the production of synthetic threads with a lower yarn breakage rate in a simple manner. In particular, the process should allow the production of polyester-based POYs having elongation at break values in the range of 90% -165%, high uniformity in filament characteristics and a low degree of crystallization.

It was also an object of the present invention to provide a process for the production of synthetic filaments from a fiber-forming matrix polymer-based mixture which allows the use of non-granulated strain-increasing agents, and thus much less expensive than in the prior art Technique known method.

Another object of the present invention was to provide a method for spinning synthetic threads, which is industrially and inexpensively feasible. In particular, the inventive method should allow the production of POYs with the highest possible take-off speeds, preferably ≥ 2500 m / min.

According to the invention, the synthetic threads should be able to be further processed in a simple manner. In particular, the POYs obtainable according to the invention should allow further processing in a draw or draw texturing process, preferably at high processing speeds, with a small number of yarn breaks.

These and other objects which are not explicitly mentioned, but which can be readily deduced or deduced from the contexts discussed hereinbelow, are solved by a process for the production of synthetic threads having all the features of patent claim 1. Advantageous modifications of the method according to the invention are disclosed in the claims 1 back Subclaims under protection. The synthetic thread obtainable by the process is described in the independent product claim. The further processing of the synthetic thread in a stretch or a draw texturing process is protected in claim 12, whereas claim 13 relates to the use of the synthetic thread for the production of staple fibers.

By using at least one second amorphous additive polymer which is incompatible with the fiber-forming matrix polymer in a process for producing synthetic filaments from a melt-based matrix polymer-based melt mixture, which process comprises adding to the fiber-forming matrix polymer at least is added in an amount of 0.05 to 5 wt .-%, based on the total weight of fiber-forming matrix polymer and with this incompatible additive polymer, wherein the additive polymer is obtainable by multiple initiation, it succeeds not without Another foreseeable way to provide a process for the production of synthetic filaments from a fiber-forming matrix polymer-based mixture, which enables the production of synthetic filaments with a lower yarn breakage rate in a simple manner. In particular, granulation of the strain-increasing agent is no longer necessary for the process according to the invention.

• Das erfindungsgemäße Verfahren ist auf einfache Art und Weise, großtechnisch und kostengünstig durchführbar. Insbesondere erlaubt das Verfahren das Spinnen und Aufspulen bei hohen Abzugsgeschwindigkeiten.
• Aufgrund der hohen Gleichmäßigkeit des durch das Verfahren erhältlichen synthetischen Fadens ist es auf einfache Art und Weise möglich, einen guten Spulenaufbau einzustellen, der eine gleichmäßige und nahezu fehlerfreie Anfärbung und Weiterverarbeitung des synthetischen Fadens erlaubt.
• Das erfindungsgemäße Verfahren ist insbesondere zur Herstellung von POYs auf Polyesterbasis mit Reißdehnungswerten im Bereich von 90 % - 165 %, einer hohen Gleichmäßigkeit bezüglich der Filament-Kennwerte sowie einem geringen Kristallisationsgrad geeignet.
• Die durch das Verfahren erhältlichen synthetischen Fäden können auf einfache Art und Weise, großtechnisch und kostengünstig weiterverarbeitet werden. Beispielsweise können die erfindungsgemäßen POYs bei hohen Geschwindigkeiten und einer geringen Anzahl an Fadenbrüchen gestreckt oder strecktexturiert werden.

At the same time, the inventive method has a number of other advantages. These include:

• The method according to the invention can be carried out in a simple manner, on an industrial scale and inexpensively. In particular, the method allows spinning and winding at high take-off speeds.
• Due to the high degree of uniformity of the synthetic thread obtainable by the method, it is possible in a simple manner to set a good package structure which permits a uniform and almost error-free dyeing and further processing of the synthetic thread.
• The process according to the invention is particularly suitable for the production of POYs based on polyester with elongation at break values in the range from 90% to 165%, a high uniformity with regard to the filament characteristics and a low degree of crystallization.
• The synthetic threads obtainable by the process can be further processed in a simple manner, industrially and inexpensively. For example, the inventive POYs can be stretched or draw texturized at high speeds and with a small number of thread breaks.

The process of the present invention relates to the production of synthetic filaments from a melt-forming matrix polymer-based melt mixture.

The spinning can be carried out both by a direct spinning process in which the strain-increasing agent in the form of a melt is metered into the melt of the matrix polymer, and by an extruder spinning process in which the strain-increasing agent is metered as a solid to the matrix polymer and subsequently melted. Further details of the above-mentioned methods can be found in the prior art, for example in the publications EP 0 047 464 B, WO 99/07 927, DE 100 49 617 and DE 100 22 889, the disclosure of which is hereby incorporated by reference.

In the context of the present invention, synthetic filaments denote all types of filaments obtainable by spinning thermoplastically processable mixtures of synthetic polymers. They include inter alia staple fibers (spun fibers), textile filaments such as plain yarns, POYs, FOYs, and engineering filaments.

Further details on synthetic threads and on the groups mentioned, in particular with regard to their material properties and the usual production conditions, can be obtained from the prior art, for example from Fourne synthetic fibers: production, machines and apparatuses, properties; Handbook for System Design, Machine Design and Operation "Munich, Vienna, Hanser Verlag 1995, as well as the publications DE 199 37 727 (staple fibers), DE 199 37 728 and DE 199 37 729 (technical yarns) and WO 99/07 927 (POYs) The disclosure of these documents is therefore explicitly referenced.

In a particularly preferred embodiment of the present invention, the process according to the invention is used for the production of staple fibers, plain yarns, POYs, FOYs or technical filaments. It has proven to be particularly suitable for the production of POYs.

Suitable fiber-forming matrix polymers according to the invention are thermoplastically processable polymers, preferably polyamides, such as polyamide-6 and polyamide-6,6, and polyesters. Also mixtures of different polymers are conceivable. For the purposes of the present invention, polyesters are preferred, in particular polyethylene terephthalate (PET), polyethylene naphthalate, polytrimethylene terephthalate (PTMT) and polybutylene terephthalate (PBT). In a particularly preferred embodiment of the present invention, the matrix polymer is Polyethylene terephthalate, polytrimethylene terephthalate or polybutylene terephthalate, especially polyethylene terephthalate.

Homopolymers are preferred according to the invention. But there are also copolymers, preferably polyester copolymers with a proportion of up to about 15 mol% of conventional comonomers, such as. As diethylene glycol, triethylene glycol, 1,4-cyclohexanedimethanol, polyethylene glycol, isophthalic acid and / or adipic acid, in question.

The polymers according to the invention may contain, as further constituents, additives which are customary for thermoplastic molding compositions and which contribute to improving the polymer properties. Examples which may be mentioned as such are: antistatic agents, antioxidants, flame retardants, lubricants, dyes, light stabilizers, polymerization catalysts and auxiliaries, adhesion promoters, matting agents and / or organic phosphites. These additives are used in the usual amount, preferably in amounts of up to 10% by weight, preferably <1% by weight, based on 100% by weight of the polymer mixture.

If a polyester is used in the process according to the invention, then it may also contain a small proportion (maximum 0.5% by weight) of branching components, ie, for example. As polyfunctional acids, such as trimellitic acid, pyromellitic acid, or tri- to hexavalent alcohols, such as trimethylolpropane, pentaerythritol, dipentaerythritol, glycerol, or corresponding hydroxy acids.

According to the invention an additive polymer is added to the matrix polymer in an amount of at least 0.05 wt .-%, wherein the additive polymer must be amorphous and substantially insoluble in the matrix polymer. In essence, the two polymers are incompatible with each other and form two phases that can be distinguished microscopically. Furthermore, the additive polymer must have a

Glass transition temperature (determined by DSC with 10 ° C / min heating rate) of more than 100 ° C and be thermoplastically processable. The melt viscosity of the additive polymer should be selected such that the ratio of its melt viscosity extrapolated to zero measurement time, measured at an oscillation rate of 2.4 Hz and a temperature equal to the melting temperature of the matrix polymer plus 34.0 ° C is (for polyethylene terephthalate 290 ° C) relative to that of the matrix polymer, measured under the same conditions, between 1: 1 and 10: 1. Ie. the melt viscosity of the additive polymer is at least equal to or preferably higher than that of the matrix polymer.

The ratio of the melt viscosity of the copolymer to that of the matrix polymer is preferably between 1.4: 1 and 8: 1 under the above-mentioned conditions. A ratio of the melt viscosities of between 1.7: 1 and 6.5: 1 is particularly preferred In these conditions, the average particle size of the additive polymer is 140-350 nm.

The amount of the additive polymer to be added to the matrix polymer is between 0.05% by weight and 5% by weight, based on the total weight of the polymer mixture. For many applications, for example for the production of POYs, addition levels of less than 1.5%, at take-off speeds over 3500 and up to 6000 m / min and more, often even less than 1.0% are sufficient, which is a significant cost advantage.

The mixing of the additive polymer with the matrix polymer is carried out in a manner known per se. It is described, for example, in WO 99/07 927 or DE 100 22 889, the disclosure of which is hereby incorporated by reference.

The spinning of the polymer mixture takes place at temperatures, depending on the matrix polymer, in the range of 220 to 320 ° C.

• 1. Ein Polymer, das durch Polymerisation von Monomeren der allgemeinen Formel (I):
  
  erhältlich ist, wobei R¹ und R² Substituenten bestehend aus den optionalen Atomen C, H, O, S, P und Halogenatomen sind und die Summe des Molekulargewichts von R¹ und R² mindestens 40 beträgt. Beipielhafte Monomereinheiten umfassen Acrylsäure, Methacrylsäure, und CH₂ = CR - COOR', wobei R ein H-Atom oder eine CH₃-Gruppe und R' ein C_1-15-Alkylrest oder ein C_5-12-Cycloalkylrest oder ein C_6-14-Arylrest ist, sowie Styrol und C_1-3-alkylsubstituierte Styrole.
• 2. Ein Copolymer, welches folgende Monomereinheiten enthält:

  A =

  Acrylsäure, Methacrylsäure oder CH₂ = CR - COOR', wobei R ein H-Atom oder eine CH₃-Gruppe und R' ein C_1-15-Alkylrest oder ein C_5-12-Cycloalkylrest oder ein C_6-14-Arylrest ist,

  B =

  Styrol oder C_1-3-alkylsubstituierte Styrole,

  wobei das Copolymer aus 60 bis 98 Gew.% A und 2 bis 40 Gew.-% B, vorzugsweise aus 83 bis 98 Gew.% A und 2 bis 17 Gew.% B, und besonders bevorzugt aus 90 bis 98 Gew. -% A und 2 bis 10 Gew.-% B (Summe =100 Gew.-%) besteht.
• 3. Ein Copolymer, welches folgende Monomereinheiten enthält:

  C =

  Styrol oder C_1-3-alkylsubstituierte Styrole,

  D =

  eines oder mehrere Monomere der Formel II, III oder IV

  
  wobei R³, R⁴ und R⁵ jeweils ein H-Atom oder ein C_1-15-Alkylrest oder ein C_6-14-Arylrest oder ein C_5-12-Cycloalkylrest sind,
  wobei das Copolymer aus 15 bis 95 Gew.-% C und 2 bis 80 Gew.-% D, vorzugsweise aus 50 bis 90 Gew.-% C und 10 bis 50 Gew.-% D und besonders bevorzugt aus 70 bis 85 -% C und 15 bis 30 Gew.-% D besteht, wobei die Summe aus C und D zusammen 100 Gew.-% ergibt.
• 4. Ein Copolymer, welches folgende Monomereinheiten enthält:

  E =

  Acrylsäure, Methacrylsäure oder CH₂ = CR - COOR', wobei R ein H-Atom oder eine CH₃-Gruppe und R' ein C_1-15-Alkylrest oder ein C_5-12-Cycloalkylrest oder ein C_6-14-Arylrest ist,

  F =

  Styrol oder C_1-3-alkylsubstitutierte Styrole,

  G =

  eines oder mehrere Monomere der Formel II, III oder IV

  

wobei R³, R⁴ und R⁵ jeweils ein H-Atom oder ein C_1-15-Alkylrest oder ein C_5-12-Cycloalkylrest oder ein C_6-14-Arylrest sind,

H =

eines oder mehrerer etyhlenisch ungesättigter mit E und/oder mit F und/oder G copolymerisierbarer Monomerer aus der Gruppe, welche aus α-Methylstyrol, Vinylacetat, Acrylsäureestern, Methacrylsäureestern, die von E verschieden sind, Acrylnitril, Acrylamid, Methacrylamid, Vinylchlorid, Vinylidenchlorid, halogensubstituierten Styrolen, Vinylethern, Isopropenylethern und Dienen besteht,

wobei das Copolymer aus 30 bis 99 Gew.-% E, 0 bis 50 Gew.-% F, 0 bis 50 Gew.-% G und 0 bis 50 Gew.-% H, vorzugsweise aus 45 bis 97 Gew.-% E, 0 bis 30 Gew.-% F, 3 bis 40 Gew.-% G und 0 bis 30 Gew.-% H und besonders bevorzugt aus 60 bis 94 Gew.-% E, 0 bis 20 Gew.-% F, 6 bis 30 Gew.-% G und 0 bis 20 Gew.-% H besteht, wobei die Summe aus E, F, G und H zusammen 100 Gew.-% ergibt.The additive polymers to be added to the fiber-forming polymer in the context of the invention may, if they have the abovementioned properties, have a different chemical composition. Particularly suitable additive polymers according to the invention include the following polymers and / or copolymers:

• 1. A polymer obtained by polymerizing monomers of the general formula (I):
  
  is available, wherein R ¹ and R ^{2 are} substituents consisting of the optional atoms C, H, O, S, P and halogen atoms and the sum of the molecular weight of R ¹ and R ^{2 is} at least 40. Exemplary monomer units include acrylic acid, methacrylic acid, and CH ₂ = CR - COOR 'where R is H or CH ₃ and R' is C _1-15 alkyl or C _5-12 cycloalkyl or C _{6 -14} -aryl, as well as styrene and C _1-3 alkyl-substituted styrenes.
• 2. A copolymer containing the following monomer units:

  A =

  Acrylic acid, methacrylic acid or CH ₂ = CR - COOR ', where R is H or CH ₃ and R' is C _1-15 alkyl or C _5-12 cycloalkyl or C _6-14 aryl is

  B =

  Styrene or C _1-3 alkyl-substituted styrenes,

  wherein the copolymer of 60 to 98 wt.% A and 2 to 40 wt.% B, preferably 83 to 98 wt.% A and 2 to 17 wt.% B, and particularly preferably 90 to 98 wt.% A and 2 to 10 wt .-% B (total = 100 wt .-%) consists.
• 3. A copolymer containing the following monomer units:

  C =

  Styrene or C _1-3 alkyl-substituted styrenes,

  D =

  one or more monomers of the formula II, III or IV

  
  where R ³ , R ⁴ and R ^{5 are} each an H atom or a C _1-15 -alkyl radical or a C _6-14 -aryl radical or a C _5-12 -cycloalkyl radical,
  wherein the copolymer consists of 15 to 95% by weight C and 2 to 80% by weight D, preferably from 50 to 90% by weight C and 10 to 50% by weight D and particularly preferably from 70 to 85% C and 15 to 30 wt .-% D, wherein the sum of C and D together gives 100 wt .-%.
• 4. A copolymer containing the following monomer units:

  E =

  Acrylic acid, methacrylic acid or CH ₂ = CR - COOR ', where R is H or CH ₃ and R' is C _1-15 alkyl or C _5-12 cycloalkyl or C _6-14 aryl is

  F =

  Styrene or C _1-3 alkyl-substituted styrenes,

  G =

  one or more monomers of the formula II, III or IV

  

where R ³ , R ⁴ and R ^{5 are} each an H atom or a C _1-15 -alkyl radical or a C _5-12 -cycloalkyl radical or a C _6-14 -aryl radical,

H =

one or more ethylenically unsaturated monomers copolymerizable with E and / or with F and / or G from the group consisting of α-methylstyrene, vinyl acetate, acrylic esters, methacrylates other than E, acrylonitrile, acrylamide, methacrylamide, vinyl chloride, vinylidene chloride, halogen-substituted styrenes, vinyl ethers, isopropenyl ethers and dienes,

wherein the copolymer of 30 to 99 wt .-% E, 0 to 50 wt .-% F, 0 to 50 wt .-% G and 0 to 50 wt .-% H, preferably from 45 to 97 wt .-% E , 0 to 30 wt .-% F, 3 to 40 wt .-% G and 0 to 30 wt .-% H and particularly preferably from 60 to 94 wt .-% E, 0 to 20 wt .-% F, 6 up to 30% by weight of G and 0 to 20 wt% H, the sum of E, F, G and H together being 100 wt%.

Component H is an optional component. Although the advantages to be achieved according to the invention can already be achieved by copolymers comprising components from groups E to G, the advantages to be achieved according to the invention also occur if further monomers from group H are involved in the construction of the copolymer to be used according to the invention

The component H is preferably selected so that it has no adverse effect on the properties of the copolymer to be used according to the invention.

The component H can u. a. Therefore, it can be used to desirably modify the properties of the copolymer, for example by increasing or improving the flow properties when the copolymer is heated to the melting temperature, or reducing a residual color in the copolymer or by using a polyfunctional monomer, in this way and to introduce some degree of crosslinking into the copolymer.

In addition, H can also be chosen so that a copolymerization of components E to G at all possible or supported, as in the case of MSA and MMA, which do not copolymerize per se, but copolymerize readily with the addition of a third component such as styrene.

Suitable monomers for this purpose include vinyl esters, esters of acrylic acid, for example methyl and ethyl acrylate, esters of methacrylic acid other than methyl methacrylate, for example butyl methacrylate and ethylhexyl methacrylate, acrylonitrile, acrylamide, methacrylamide, vinyl chloride, vinylidene chloride, styrene, α- Methylstyrene and the various halogen-substituted Styrenes, vinyl and isopropenyl ethers, dienes such as 1,3-butadiene and divinylbenzene. The color reduction of the copolymer can be achieved, for example, particularly preferably by using an electron-rich monomer, for example a vinyl ether, vinyl acetate, styrene or α-methylstyrene.

Particularly preferred among the compounds of component H are aromatic vinyl monomers such as styrene or α-methylstyrene.

The preparation of the additive polymers to be used according to the invention is known per se. They can be prepared in bulk, solution, suspension or emulsion polymerization. Helpful hints can be found regarding the bulk polymerization in Houben-Weyl, Volume E20, Part 2 (1987), page 1145ff. Information on solution polymerization can be found on page 1156ff. The suspension polymerization technique is also described on page 1149ff, while the emulsion polymerization is carried out and explained there on page 1150ff.

Within the scope of the invention, particular preference is given to bead polymers whose particle size is in a particularly favorable range. With particular preference the additive polymers to be used according to the invention by, for example, mixing into the melt of the fiber polymers are present in the form of particles having an average diameter of 0.1 to 1.0 mm. However, larger or smaller beads can also be used.

All copolymers according to the invention are commercially available or can be prepared by a process familiar to the person skilled in the art.

For polymer blends of polyethylene terephthalate for textile applications, such as POYs having an intrinsic viscosity of about 0.55 to 0.75 dl / g and additive polymers of type 1, 2, 3 or 4, preference is given to additive polymers having viscosity numbers in the range from 70 to 130 cm ³ / g.

In the process of the invention, an additive polymer is added, which is obtainable by multiple initiation. The term "multiple initiation" encompasses both a single or multiple re-initiation of free-radical polymerization, i. H. the single or multiple re-addition of initiator at later reaction times, as well as the radical polymerization in the presence of a mixture comprising at least two initiators with graded half-lives, which is particularly preferred in the context of the present invention. Graded half-life means in the context of the present invention that the at least two initiators each have different half-lives at a certain temperature or have the same half-life, but in different temperature ranges. Preferably, initiators are used, each having a half-life of one hour in temperature ranges which are at least 10 ° C apart. In each case a single compound can be used as the initiator as an initiator from the individual temperature ranges, but it is also possible to use two or more initiators with the corresponding half-lives from the corresponding temperature ranges.

Such polymerizations are described, for example, in the publications US Pat. No. 4,588,798, US Pat. No. 4,605,717, EP 489 318, DE 199 17 987 and the publications cited therein. The disclosure of the cited references is hereby incorporated by reference.

In the context of the present invention, it has proven particularly expedient to use an initiator mixture which has an initiator I, with a half-life T ₁ of one hour in the range 70 to 85 ° C. and a further initiator I ₂ with a half-life T ₂ of one hour in the range 85 to 100 ° C having. Further initiators I _n , which can be used if appropriate, preferably have decomposition temperatures T _n between T ₁ and T ₂ .

The amount of initiator mixture to be used can be varied within relatively wide limits; It can thus be controlled, the polymerization, and the polymerization temperature can be influenced by the amount of initiators used. The quantities used according to the invention are given in parts by weight of initiator per 100 parts by weight of monomers. It is advantageous to use a total amount of initiator mixture of about 0.05 to 1.0 parts by weight per 100 parts by weight of monomers, suitably 0.05 to 0.5 parts by weight, in particular 0.15 to 0.4 parts by weight per 100 parts by weight of monomers.

The weight ratio of the individual initiators to one another in the initiator mixture can likewise be varied within relatively wide limits; Preferably, the weight ratio of the individual initiators to one another is in the range from 1: 1 to 1:10, preferably 1: 1 to 1: 4. Suitable amounts and mixing ratios can be determined on the basis of simple preliminary experiments.

Suitable initiators which can be used according to the invention include the per se conventional initiators which are used for radical formation in free-radically initiated polymerizations. These include compounds such as organic peroxides such as dicumyl peroxide, diacyl peroxides such as dilauroyl peroxide, peroxydicarbonates such as diisopropyl peroxydicarbonate, peresters such as tert. Butyl peroxy-2-ethylhexanoate and the like. Other types of compounds which can form radicals are also suitable in the context of the present invention. These include in particular azo compounds such as 2,2'-azobisisobutyronitrile and 2,2'-azobis- (2,4-dimethylvaleronitrile).

• tert. Amylperoxy-pivalat Halbwertszeit T (1 Stunde) = 71°C,
• 2,2'-Azobis-(2,4-dimethylvaleronitril) T (1 Stunde) = 71°C,
• Di-(2,4-dichlorbenzoyl)-peroxid T (1 Stunde) = 72°C,
• tert. Butylperoxy-pivalat T (1 Stunde) = 74°C,
• 2,2'-Azobis-(2-amidinopropane)-dihydrochlorid T (1 Stunde) = 74°C,
• Di-(3, 5, 5-trimethyl-hexanoyl)-peroxid T(1 Stunde) = 78°C,
• Dioctanoylperoxid T (1 Stunde) = 79 °C ,
• Dilauroylperoxid T (1 Stunde) = 80 °C,
• Didecanoylperoxid T (1 Stunde) = 80 °C,
• 2,2'-Azobis-(N,N'-dimethylenisobutyramidine) T (1 Stunde) = 80°C,
• Di-(2-methylbenzoyl)-peroxid T (1 Stunde) = 81°C,
• 2,2'-Azobisisobutyronitril T (1 Stunde) = 82°C,
• Dimethyl-2,2'-azobisisobutyrat T (1 Stunde) = 83°C,
• 2,2'-Azobis-(2-methylbutyronitril) T (1 Stunde) = 84°C,
• 2,5-Dimethyl-2,5-di-(2-ethylhexanoylperoxy)-hexan T (1 Stunde) = 84°C,
• 4,4'-Azobis-(cyanopentansäure) T (1 Stunde) = 86°C,
• Di-(4-methylbenzoyl)-peroxid T (1 Stunde) = 89°C,
• Dibenzoyl-peroxid T (1 Stunde) = 91°C,
• tert. Amylperoxy-2-ethylhexanoat T(1 Stunde) = 91°C,
• tert. Butylperoxy-2-ethylhexanoat T (1 Stunde) = 92 °C,
• tert. Butylperoxy-isobutyrat T(1 Stunde) = 96°C.

Initiator mixtures whose components are selected from the following initiators have proven particularly useful:

• tert. Amyl peroxy pivalate half-life T (1 hour) = 71 ° C,
• 2,2'-azobis (2,4-dimethylvaleronitrile) T (1 hour) = 71 ° C,
• Di (2,4-dichlorobenzoyl) peroxide T (1 hour) = 72 ° C,
• tert. Butylperoxy-pivalate T (1 hour) = 74 ° C,
• 2,2'-azobis (2-amidinopropane) dihydrochloride T (1 hour) = 74 ° C,
• Di (3, 5, 5-trimethylhexanoyl) peroxide T (1 hour) = 78 ° C,
• Dioctanoyl peroxide T (1 hour) = 79 ° C,
• Dilauroyl peroxide T (1 hour) = 80 ° C,
• Didecanoyl peroxide T (1 hour) = 80 ° C,
• 2,2'-azobis (N, N'-dimethyleneisobutyramidine) T (1 hour) = 80 ° C,
• Di (2-methylbenzoyl) peroxide T (1 hour) = 81 ° C,
• 2,2'-azobisisobutyronitrile T (1 hour) = 82 ° C,
• Dimethyl 2,2'-azobisisobutyrate T (1 hour) = 83 ° C,
• 2,2'-azobis (2-methylbutyronitrile) T (1 hour) = 84 ° C,
• 2,5-dimethyl-2,5-di (2-ethylhexanoylperoxy) hexane T (1 hour) = 84 ° C,
• 4,4'-azobis (cyanopentanoic acid) T (1 hour) = 86 ° C,
• Di (4-methylbenzoyl) peroxide T (1 hour) = 89 ° C,
• Dibenzoyl peroxide T (1 hour) = 91 ° C,
• tert. Amyl peroxy-2-ethylhexanoate T (1 hour) = 91 ° C,
• tert. Butyl peroxy-2-ethylhexanoate T (1 hour) = 92 ° C,
• tert. Butyl peroxy isobutyrate T (1 hour) = 96 ° C.

Very particular preference according to the invention is given to peroxidic initiators.

The polymerization can be carried out largely or over a wide range under isothermal conditions. In a particularly preferred embodiment In the present invention, the polymerization takes place in at least two steps. In a first step, initially at a lower temperature, preferably at a temperature between 60 and less than 85 ° C, polymerized. In a second step, the polymerization is continued at a higher temperature, preferably at a temperature between 85 and 120 ° C.

Preferably, the additive polymer has a residual monomer content of less than 0.62 wt .-%, advantageously less than 0.47 wt .-%, preferably less than 0.42 wt .-%, each based on the total weight of the additive polymer on. In a particularly preferred embodiment of the present invention, the residual monomer content of the additive polymer is less than 0.37 wt .-%, preferably less than 0.30 wt .-%, advantageously less than 0.25 wt .-%, in particular less than 0.20 wt .-%, each based on the total weight of the additive polymer.

According to the invention, the residual monomer content in the additive polymer denotes the amount of monomer which remains in the additive polymer after polymerization and polymer isolation. Typically, in polymers prepared by free radical polymerization, it is in the range of 0.65% to 1.0% by weight, based on the total weight of the polymer. Methods for reducing the residual monomer content of a polymer are known in the art. For example, it can be lowered by degassing the polymer melt, preferably in the extruder directly before spinning. In addition, it is also possible by suitable choice of the polymerization parameters to obtain polymers having a reduced residual monomer content.

In the context of the present invention, it is furthermore extremely advantageous to add a flow aid to the additive polymer. This Rieselhilfen all aids that powdery or granular, especially hygroscopic substances are added in small amounts to their clumping or To prevent caking and thus to ensure permanent free flow. Water-soluble, hydrophobicizing or moisture-adsorbing powders of kieselguhr, pyrogenic silicas, tricalcium phosphate, calcium silicates, Al ₂ O ₃ , MgO, M _g CO ₃ , ZnO, stearates, fatty amines (see CD Römpp Chemie Lexikon - Version 1.0, Stuttgart / New York: Georg Thieme Verlag 1995) in question. In the context of the present invention, such flow aids have proved to be of limited suitability, since they are disadvantageous for the spinning process. First, they can be deposited in the spinning device and thus lead to blockages of the lines and nozzles and thus to malfunction. Furthermore, there is the danger of worsening the material properties of the resulting synthetic threads by the "foreign substances" and of increasing the yarn breakage rate during spinning.

• 1. Ein Polymer, das durch Polymerisation von Monomeren der allgemeinen Formel (I):
  
  erhältlich ist, wobei R¹ und R² Substituenten bestehend aus den optionalen Atomen C, H, O, S, P und Halogenatomen sind und die Summe des Molekulargewichts von R¹ und R² mindestens 40 beträgt. Beipielhafte Monomereinheiten umfassen Acrylsäure, Methacrylsäure, und CH₂ = CR - COOR', wobei R ein H-Atom oder eine CH₃-Gruppe und R' ein C_1-15-Alkylrest oder ein C_5-12-Cycloalkylrest oder ein C_6-14-Arylrest ist, sowie Styrol und C_1-3-alkylsubstituierte Styrole.
• 2. Ein Copolymer, welches folgende Monomereinheiten enthält:

  A =

  Acrylsäure, Methacrylsäure oder CH₂ = CR - COOR', wobei R ein H-Atom oder eine CH₃-Gruppe und R' ein C_1-15-Alkylrest oder ein C_5-12-Cycloalkylrest oder ein C_6-14-Arylrest ist,

  B =

  Styrol oder C_1-3-alkylsubstituierte Styrole,

  
  wobei das Copolymer aus 60 bis 98 Gew.-% A und 2 bis 40 Gew.% B, vorzugsweise aus 83 bis 98 Gew.-% A und 2 bis 17 Gew.% B, und besonders bevorzugt aus 90 bis 98 Gew. -% A und 2 bis 10 Gew.-% B (Summe = 100 Gew.-%) besteht.
• 3. Ein Copolymer, welches folgende Monomereinheiten enthält:

  C =

  Styrol oder C_1-3-alkylsubstituierte Styrole,

  D =

  eines oder mehrere Monomere der Formel II, III oder IV

  
  wobei R³, R⁴ und R⁵ jeweils ein H-Atom oder ein C_1-15-Alkylrest oder ein C_6-14-Arylrest oder ein C_5-12-Cycloalkylrest sind, wobei das Copolymer aus 15 bis 95 Gew.-% C und 2 bis 80 Gew.-% D, vorzugsweise aus 50 bis 90 Gew.-% C und 10 bis 50 Gew.-% D und besonders bevorzugt aus 70 bis 85 -% C und 15 bis 30 Gew.-% D besteht, wobei die Summe aus C und D zusammen 100 Gew.-% ergibt.
• 4. Ein Copolymer, welches folgende Monomereinheiten enthält:

  E =

  Acrylsäure, Methacrylsäure oder CH₂ = CR - COOR', wobei R ein H-Atom oder eine CH₃-Gruppe und R' ein C_1-15-Alkylrest oder ein C_5-12-Cycloalkylrest oder ein C_6-14-Arylrest ist,

  F =

  Styrol oder C_1-3-alkylsubstitutierte Styrole,

  G =

  eines oder mehrere Monomere der Formel II, III oder IV

  

  wobei R³, R⁴ und R⁵ jeweils ein H-Atom oder ein C_1-15-Alkylrest oder ein C_5-12-Cycloalkylrest oder ein C_6-14-Arylrest sind,

  H =

  eines oder mehrerer etyhlenisch ungesättigter mit E und/oder mit F und/oder G copolymerisierbarer Monomerer aus der Gruppe, welche aus α-Methylstyrol, Vinylacetat, Acrylsäureestern, Methacrylsäureestern, die von E verschieden sind, Acrylnitril, Acrylamid, Methacrylamid, Vinylchlorid, Vinylidenchlorid, halogensubstituierten Styrolen, Vinylethern, Isopropenylethern und Dienen besteht,

wobei das Copolymer aus 30 bis 99 Gew.-% E, 0 bis 50 Gew.-% F, 0 bis 50 Gew.-% G und 0 bis 50 Gew.% H, vorzugsweise aus 45 bis 97 Gew.-% E, 0 bis 30 Gew.-% F, 3 bis 40 Gew.-% G und 0 bis 30 Gew.-% H und besonders bevorzugt aus 60 bis 94 Gew.-% E, 0 bis 20 Gew.-% F, 6 bis 30 Gew.-% G und 0 bis 20 Gew.-% H besteht, wobei die Summe aus E, F, G und H zusammen 100 Gew.-% ergibt.Therefore, according to the invention, polymers and / or copolymers are particularly preferred as flow aids. The following polymers and / or copolymers have proven to be particularly useful:

• 1. A polymer obtained by polymerizing monomers of the general formula (I):
  
  is available, wherein R ¹ and R ^{2 are} substituents consisting of the optional atoms C, H, O, S, P and halogen atoms and the sum of the molecular weight of R ¹ and R ^{2 is} at least 40. Exemplary monomer units include acrylic acid, methacrylic acid, and CH ₂ = CR - COOR 'where R is H or CH ₃ and R' is C _1-15 alkyl or a C _5-12 cycloalkyl radical or a C _6-14 aryl radical, as well as styrene and C _1-3 alkyl-substituted styrenes.
• 2. A copolymer containing the following monomer units:

  A =

  Acrylic acid, methacrylic acid or CH ₂ = CR - COOR ', where R is H or CH ₃ and R' is C _1-15 alkyl or C _5-12 cycloalkyl or C _6-14 aryl is

  B =

  Styrene or C _1-3 alkyl-substituted styrenes,

  
  wherein the copolymer of 60 to 98 wt .-% A and 2 to 40 wt.% B, preferably from 83 to 98 wt .-% A and 2 to 17 wt.% B, and particularly preferably from 90 to 98 wt -. % A and 2 to 10 wt .-% B (total = 100 wt .-%) consists.
• 3. A copolymer containing the following monomer units:

  C =

  Styrene or C _1-3 alkyl-substituted styrenes,

  D =

  one or more monomers of the formula II, III or IV

  
  where R ³ , R ⁴ and R ^{5 are} each an H atom or a C _1-15 -alkyl radical or a C _6-14 -aryl radical or a C _5-12 -cycloalkyl radical, wherein the copolymer consists of 15 to 95% by weight C and 2 to 80% by weight D, preferably from 50 to 90% by weight C and 10 to 50% by weight D and particularly preferably from 70 to 85% C and 15 to 30 wt .-% D, wherein the sum of C and D together gives 100 wt .-%.
• 4. A copolymer containing the following monomer units:

  E =

  Acrylic acid, methacrylic acid or CH ₂ = CR - COOR ', where R is H or CH ₃ and R' is C _1-15 alkyl or C _5-12 cycloalkyl or C _6-14 aryl is

  F =

  Styrene or C _1-3 alkyl-substituted styrenes,

  G =

  one or more monomers of the formula II, III or IV

  

  where R ³ , R ⁴ and R ^{5 are} each an H atom or a C _1-15 -alkyl radical or a C _5-12 -cycloalkyl radical or a C _6-14 -aryl radical,

  H =

  one or more ethylenically unsaturated monomers copolymerizable with E and / or with F and / or G from the group consisting of α-methylstyrene, vinyl acetate, acrylic esters, methacrylates other than E, acrylonitrile, acrylamide, methacrylamide, vinyl chloride, vinylidene chloride, halogen-substituted styrenes, vinyl ethers, isopropenyl ethers and dienes,

wherein the copolymer consists of 30 to 99% by weight of E, 0 to 50% by weight of F, 0 to 50% by weight of G and 0 to 50% by weight of H, preferably of 45 to 97% by weight of E, 0 to 30 wt .-% F, 3 to 40 wt .-% G and 0 to 30 wt .-% H and particularly preferably from 60 to 94 wt .-% E, 0 to 20 wt .-% F, 6 to 30 wt .-% G and 0 to 20 wt .-% H, wherein the sum of E, F, G and H together gives 100 wt .-%.

Component H is an optional component. Although the advantages to be achieved according to the invention can already be achieved by copolymers comprising components from groups E to G, the advantages to be achieved according to the invention also occur if further monomers from group H are involved in the construction of the copolymer to be used according to the invention.

The component H is preferably selected so that it has no adverse effect on the properties of the copolymer to be used according to the invention.

The component H can u. a. Therefore, it can be used to desirably modify the properties of the copolymer, for example by increasing or improving the flow properties when the copolymer is heated to the melting temperature, or reducing a residual color in the copolymer or by using a polyfunctional monomer, in this way and to introduce some degree of crosslinking into the copolymer.

In addition, H can also be chosen so that a copolymerization of components E to G is possible or supported in the first place, as in the case of MSA and MMA, which do not copolymerize per se, but copolymerize readily with the addition of a third component such as styrene.

Among the monomers suitable for this purpose are u. a. Vinyl esters, esters of acrylic acid, for example methyl and ethyl acrylate, esters of methacrylic acid other than methyl methacrylate, for example butyl methacrylate and ethylhexyl methacrylate, acrylonitrile, acrylamide, methacrylamide, vinyl chloride, vinylidene chloride, styrene, α-methylstyrene and the various halosubstituted styrenes, vinyl and isopropenyl ethers, dienes such as 1,3-butadiene and divinylbenzene. The color reduction of the copolymer can be achieved, for example, particularly preferably by using an electron-rich monomer, for example a vinyl ether, vinyl acetate, styrene or α-methylstyrene.

Particularly preferred among the compounds of component H are aromatic vinyl monomers such as styrene or α-methylstyrene.

The preparation of said Rieselhilfen is known per se. They can be prepared in bulk, solution, suspension or emulsion polymerization. Helpful hints can be found regarding the bulk polymerization in Houben-Weyl, Volume E20, Part 2 (1987), page 1145ff. Information on solution polymerization can be found on page 1156ff. The suspension polymerization technique is also described on page 1149ff, while the emulsion polymerization is carried out and explained there on page 1150ff. Optionally, the polymers must still be ground.

According to the invention, particular preference is given to flow aids whose particle size is in a particularly favorable range. Particularly preferred are in the form of particles with a mean diameter of 0.01 to less than 100 microns ago. However, there are also Rieselhilfen be used with larger or smaller particle sizes.

The imidized copolymer types 3 and 4 can be prepared both from the monomers using a monomeric imide and by subsequent complete or preferably partial imidization of a copolymer containing the corresponding maleic acid derivative. These free-flowing aids are obtained, for example, by complete or preferably partial reaction of the corresponding copolymer in the melt phase with ammonia or a primary alkyl- or arylamine, for example aniline (Encyclopedia of Polymer Science and Engineering Vol. 16 [1989], Wiley-Verlag, page 78). , The resulting copolymers may need to be ground.

All of the copolymers according to the invention and, if present, their non-imidized starting copolymers are commercially available or can be prepared by a process familiar to the person skilled in the art.

In the context of the present invention, flow aids which have a largely identical chemical composition to the additive polymer used have proven particularly useful. Advantageously, the flow aid and the additive polymer used to at least 50 wt .-%, advantageously at least 60 wt .-%, preferably at least 70 wt.%, In particular at least 80 wt .-%, each based on the total weight of Rieselhilfe or the additive polymer used, the same repeat units. In this context, the repeating units characterize the repeating units derived from the monomers originally used in the polymer.

According to the invention, particularly advantageous results can be achieved if the flow aid and the additive polymer used to at least 90 wt .-%, preferably at least 95 wt .-%, in particular at least 97 wt .-%, each based on the total weight of the flow aid or of the additive polymer used which have the same repeat units. In a very particularly preferred embodiment of the present invention, the polymer composition of the flow aid and that of the additive polymer used are completely identical with respect to the repeating units.

In the context of the present invention, it is furthermore expedient to use a flow aid which has a similar weight average molecular weight as the additive polymer used. The weight-average molecular weight preferably deviates from the flow aid by less than 50%, advantageously by less than 30%, in particular by less than 20%, from that of the additive polymer used.

The preferred concentration range of the flow aid in the additive polymer is 0.05 to 5.0 wt .-%, preferably 0.05 to 1.0 wt .-%, each based on the total weight of the additive polymer and flow aid, and depends on the surface and thus on the average diameter of the additive polymers. For a bead polymer of average grain size of 0.7 mm, a concentration of the flow aid of 0.05 to 0.3 wt .-% is preferred. As the diameter of the beads decreases, the concentration of the flow aid required for the flow-promoting effect increases. At too low a concentration of the flow aid the flow-promoting effect is incomplete, while at too high concentrations of Rieselhilfe no further improvement of the flow behavior is achieved, but it enters a strong, technically undesirable dust formation by the excess, finely divided Rieselhilfe powder.

Conveniently, the trickle aid is prepared by an emulsion polymerization process and isolated by spray drying. The spray drying can be done in a known per se. Exemplary descriptions of the spray drying can be found in DE 332 067 or Ullmanns Enzyklopadie der technischen Chemie, 5th edition (1988), B 2, page 4-23. Depending on the spray unit (single-fluid nozzle, two-fluid nozzle or atomizer disk), particles with an average particle diameter of 20 to 300 μm are obtained.

The mixing of the additive polymer and the flow-through aid for the production of a homogeneous (as far as possible) strain-increasing agent can be carried out in a manner known per se. Further details are described, for example, in Ullmanns Enzyklopadie der technischen Chemie, 5th edition (1988) and in Rompps Chemie Lexikon (CD) - Version 1.0, Stuttgart / New York: Georg Thieme Verlag 1995.

In the context of the present invention, it has proved to be extremely advantageous to mix the additive polymer, which has preferably been dried using a fluidized-bed dryer, and the spray-dried free-flowing aid, using a fluidized bed dryer. Details of the fluidized bed process can also be found in the specialist literature, for example Ullmanns Enzyklopadie der technischen Chemie, 5th edition (1988) and Rompps Chemie Lexikon (CD) - Version 1.0, Stuttgart / New York: Georg Thieme Verlag 1995.

The strain-increasing agent to be used according to the invention is not granulated in contrast to the prior art. Granulation in this context refers to the production of so-called pellets (granules) of the same shape and size. The polymer to be granulated is usually melted in a single or twin-screw extruder and fed to a pelletizer. The crushing can be done both by cold pelletization and by hot pelletization. Cold pelletizing takes place through the granulating nozzle Strands, strips or thin films produced, which are comminuted after solidification by means of rotating knives. In hot pelletizing, the plasticized polymer is forced through the die and the outgoing strand is comminuted by a rotating knife, which is usually mounted on the die plate. The cooling of the melt takes place after pelletizing usually either with air or water.

The production of the synthetic threads from the polymer blends according to the invention by melt spinning is carried out using spinning devices known per se, as described, for example, in the publications DE 199 37 727 (staple fibers), DE 199 37 728 and DE 199 37 729 (technical yarns) and WO 99 / 07 927 (POYs). The disclosure of these documents is therefore explicitly incorporated by reference.
Since the inventive method for the production of POYs has proven to be particularly useful, a particularly preferred embodiment of the inventive method for producing POYs will be described below. The transfer of the teaching according to the invention to methods for the production of other synthetic threads is immediately obvious to the person skilled in the art.

The melt spinning of POYs is preferably carried out at spinning take-off speeds of at least 2500 m / min. Here, the filter pack according to the prior art with filter devices and / or loose filter media (eg., Steel sand) equipped.

The molten polymer mixture is pressed after the shear and filtration treatment in the nozzle package through the holes of the nozzle plate. In the subsequent cooling zone, the melt filaments are cooled by means of cooling air below its softening temperature, so that sticking or upsetting at the following thread guide is avoided. The formation of the cooling zone is not critical, provided that a homogeneous, the filament bundle uniformly penetrating air flow is ensured. Thus, a Luftruhezone to delay the cooling can be provided directly below the nozzle plate. The cooling air can be supplied by transverse or radial blowing from an air conditioning system or removed by means of a cooling tube from the environment by self-priming.

After cooling, the filaments are bundled and treated with spin oil. For this purpose, oilers are used, to which the spinning oil is fed as an emulsion of metering pumps. The prepared thread advantageously passes through an Entanglingeinrichtung (Verschlingeinrichtung) to improve the thread closing. Also, handling and security organs may be appropriate before the thread passes to the winding unit and is wound there on cylindrical bobbin to packages. The peripheral speed of the thread package is automatically controlled and is equal to the winding speed. Due to its traversing movement, the withdrawal speed of the thread can be 0.2 - 2.5% higher than the winding speed. Optionally, driven godets can be used after preparation or before winding. The peripheral speed of the first godet system is referred to as the take-off speed. Other godets can be used for stretching or relaxing.

The incompatibility of the two polymers causes the additive polymer immediately after the exit of the polymer mixture from the spinneret predominantly forms radially symmetric elongated particles in the matrix polymer in the yarn running direction. Preferably, the length / diameter ratio is> 2. The diameter (d) was determined perpendicularly and the length parallel to the thread running direction. Best conditions were obtained when the mean particle diameter (arithmetic mean) d ₅₀ ≤ 400 nm, and the proportion of particles> 1000 nm in a sample cross section was less than 1%.

The influence of these particles by the spinning delay could be detected analytically. Investigations of the filaments by the TEM method (transmission electron microscopy) have shown that there is a fibril-like structure. The mean diameter of the fibrils was estimated to be about 40 nm. The length / diameter ratio of the fibrils was> 50. If these fibrils are not formed or are the additive particles after exiting the spinneret in diameter too large or is the size distribution too uneven, which is the case with insufficient viscosity ratio, the effect is lost ,

The rolling action described in the literature could not be reconstructed with the additive polymer according to the invention. The evaluation of microscopic examinations of fiber transverse and longitudinal sections suggests that the spinning distortion stress is conducted onto the forming additive fibrils and that the polymer matrix warps in a stress-relieved manner. As a result, the deformation of the matrix occurs under conditions that result in a reduction in the orientation and suppression of spin-induced crystallization. It makes sense to evaluate the effect on the spun yarn formation and the processing behavior

Further, for the effectiveness of the additives according to this invention, a flow activation energy of the copolymers of at least 80 kJ / mol, ie a higher flow activation energy than that of the polymer matrix, is advantageous. Under this condition, it is possible that the additive fibrils solidify in front of the polyester matrix and absorb a significant proportion of the applied spinning tension. Thus, the desired capacity increase of the spinning plant can be achieved in a simple way.

The above-described preferred embodiment of the method according to the invention is in the same way for the fast spinning of POY filaments having a POY filament titre of> 3 dtex to 20 dtex and more, as well as of POY filament titres <3 dtex, in particular microfilaments with 0, 2 to 2.0 dtex suitable.

In the method according to the invention, as a result of the added polymer additive which is obtainable by multiple initiation, the yarn breakage rate is markedly reduced compared with the processes known from the prior art. In a preferred embodiment of the present invention, in the production of POYs with a titer> 3 dtex, the yarn break rate is less than 0.75 fractions per ton of polymer blend, suitably less than 0.5 fractions per ton of polymer blend, preferably less than 0.4 fractions per mole Ton of polymer blend.

The synthetic threads obtainable by the process according to the invention can be used directly in the present form or further processed in a manner known per se. In a particularly preferred embodiment of the present invention, they are used to make staple fibers. In this case, further details for the production of staple fibers of the prior art, for example, the document DE 199 37 727 and the cited in her writings are taken.

In a further particularly preferred embodiment of the present invention, POYs produced by the process according to the invention are stretched or draw texturized. The following is important for the further processing of the spun yarn in the draw-texturing process at high speeds: Spun yarns according to this invention as roving for draw texturing - usually referred to as POY - are preferably at take-off speeds ≥ 2500 m / min, preferably> 3500 m / min, particularly preferably> 4000 m / min. These yarns must have a physical structure characterized by a specific degree of orientation and low crystallization. The characteristics of elongation at break, birefringence, degree of crystallization and boiling shrinkage have proven useful for its characterization. The polyester-based polymer mixture according to the invention is characterized by an elongation at break of the polymer filaments (POY) of at least 85% and at most 180%. The boiling shrinkage is 32-69%, the birefringence is between 0.030 and 0.075, the crystallinity is less than 20% and the tear strength is at least 17 cN / tex. The elongation at break of the polymer filaments is preferably between 85 and 160%. Particularly favorable conditions exist when the elongation at break of the polymer spun yarns is between 109 and 146%, the tensile strength at the same time is at least 22 cN / tex and the Uster value is at most 0.7%.

The synthetic POYs obtainable in this way are particularly suitable for further processing in a draw or draw texturing process. In this case, a lower number of yarn breaks can be observed during further processing. Draw texturing is carried out at different speeds, depending on the type of filament titre, with speeds of 2 dtex per filament (final titre) of speeds ≥ 750 m / min, preferably ≥ 900 m / min, being used for normal titre filaments. For microfilaments and fine titers (final titer) <2 dtex, speeds between 400 and 750 m / min are preferred. The process can be advantageously applied to these titers and in particular microfilaments between 0.15 and 1.10 dtex (final titer) per filament.

wobei

w =

Strecktexturiergeschwindigkeit in m/min

b =

Konstante, die zwischen 1,15 und 1,50 liegt,

anzuwenden.The drawing ratios to be applied are between 1.35 and 2.2 for the specified spun yarns, preference being given to drawing ratios in the upper region and vice versa for a lower degree of orientation. In stretch texturing, the draw ratio becomes due to voltage fluctuations (Surging) depending on the working speed. Draft ratios according to the formula are therefore particularly preferred: $$\mathrm{Verstreckverh}\ddot{\mathrm{a}}\mathrm{ltnis}=5\cdot {10}^{-4}\cdot \mathrm{w}(\mathrm{m}/\min )+\mathrm{b}$$

in which

w =

Draw texturing speed in m / min

b =

Constant, which is between 1.15 and 1.50,

apply.

In the following, the invention will be explained in more detail by way of example and comparative example, without the invention being restricted to this example. The specified property values, as well as the values given above, were determined as follows:

The residual monomer content of methyl methacrylate and styrene was measured by gas chromatographic headspace analysis, a method for determining volatiles in liquids and solids (including monomers in thermoplastics). The residual monomer content of N-cyclohexylmaleimide was determined by gas chromatography on a solution of the polymer in dichloromethane.

The mean grain diameter in the spray-dried flow aid was determined by laser diffraction spectroscopy using a Mastersizer Microplus from Malvem (measuring range: 0.05-555 μm).

The mean grain diameter of the spun-fiber additive beads was determined by a sieve analysis with an Alpine air-jet screening machine (type A 200 LS).

wobei

t =

Durchlaufzeit der Polymerlösung in Sekunden

t_o =

Durchlaufzeit des Lösemittels in Sekunden

c =

Konzentration in g/100 ccm

The intrinsic viscosity was determined on a solution of 0.5 g of polyester in 100 ml of a mixture of phenol and 1,2-dichlorobenzene (3: 2 parts by weight) at 25 ° C. The viscosity number VZ (also Staudinger function) is the concentration-related relative change in viscosity of a 0.5% solution of the copolymer in chloroform based on the solvent, the flow times in the Ubbelohde viscometer with hanging ball level, Schott type no. 53203 and capillary 0c according to DIN -Norm 51562 at 25 ° C were determined. The solvent used was chloroform. $$\mathrm{VZ}=(\frac{\mathrm{t}}{{\mathrm{t}}_{\mathrm{O}}}-1)\cdot \frac{1}{\mathrm{c}}$$

in which

t =

Lead time of the polymer solution in seconds

t _o =

Passing time of the solvent in seconds

c =

Concentration in g / 100 cc

To determine the melt viscosity (initial viscosity), the polymer was dried in vacuo to a water content of ≦ 1000 ppm (polyester ≦ 50 ppm). Subsequently, the polymer was introduced onto the temperature-controlled measuring plate in a cone-plate rheometer, type UM100, Physica Meßtechnik GmbH, Stuttgart / DE, under the influence of nitrogen. The measuring cone (MK210) was positioned on the measuring plate after the sample had melted, ie after about 30 seconds. The measurement was started after a further heating-up period of 60 seconds (measuring time = 0 seconds). The measuring temperature was 290 ° C for polyethylene terephthalate and additive polymers, which are added to polyethylene terephthalate, or was equal to the melting temperature (method hereafter) of the affected polymer plus 34.0 ° C. The thus determined measuring temperature corresponds to the typical processing or spinning temperature of the respective polymer. The amount of sample was chosen so that the rheometer gap was completely filled. The measurement was carried out in oscillation with the frequency 2.4 Hz (corresponding to a shear rate of 15 sec ^-1 ) and a deformation amplitude of 0.3, and determines the amount of the complex viscosity as a function of the measuring time. Thereafter, the initial viscosity was converted to the zero measurement time by linear regression.

For the determination of the melting temperature of the polymer, the polymer sample was first melted at 310 ° C for 1 min and then immediately quenched to room temperature. Subsequently, the melting temperature was determined by DSC measurement (differential scanning calorimetry) at a heating rate of 10 ° C / min. Pretreatment and measurement were done under nitrogen fogging.

The titer was determined in a known manner with a precision tare and a weighing device. The bias was suitably 0.05 cN / dtex for the oriented filaments (POYs) and 0.2 cN / dtex for the textured yarn (DTY).

Tear strength and elongation at break were determined in a Statimat meter under the following conditions; the clamping length was 200 mm for POY and 500 mm for DTY, the measuring speed was 2000 mm / min for POY and 1500 mm / min for DTY, the pretension was 0.05 cN / dtex for POY and 0.2 cN / dtex for DTY. By dividing the values for the maximum tearing load by the titer, the tear strength was determined, and the elongation at break was evaluated at maximum load.

Comparative example

Polyethylene terephthalate chips having a water content of less than 35 ppm, an intrinsic viscosity of 0.64 dl / g and a melt viscosity (at 290 ° C) of 250 Pas were fed into the intake of an extruder. Placed perpendicular to the conveying direction of the extruder screw and centric to Extrudereinzug was a downpipe through which the dried to a residual moisture content of <0.1% by weight additive was added by means of a gravimetric dosing in the catchment area above the extruder screw to the polyester chips.

The additive used was a bead polymer prepared in suspension based on MMA / styrene / N-cyclohexylmaleimide. This was a terpolymer of 89.2 wt .-% of methyl methacrylate, 8.8 wt .-% of styrene and 2 wt .-% N-cyclohexylmaleimide, wherein the terpolymer has a viscosity number VZ of about 101 cm ³ / g and a Melt viscosity (at 290 ° C) of about 1400 Pas.

The MMA / styrene / N-cyclohexylmaleimide additive with VZ 101 cm ³ / g was obtained as follows:

In a 10001 heating / cooling jacket equipped with stirrer, reflux condenser and thermometer, a mixture of 525 kg deionized water, 0.071 kg KHSO ₄ and 13 kg of a 13% aqueous solution of a polyacrylic acid was heated to 40 ° C. 525 kg of a mixture of 88.68 parts by weight of methyl methacrylate (MMA), 8.75 parts by weight of styrene, 1.99 parts by weight of N-cyclohexylmaleimide, 0.14 part by weight of 2-ethylhexyl thioglycolate, 0.09 part by weight of t-dodecylmercaptan were then added with stirring. 0.05 parts by weight of stearic acid and 0.3 parts by weight of dilauroyl peroxide added. The batch was polymerized at 80 ° C for 130 minutes and at 98 ° C for 60 minutes and then cooled to room temperature. The polymer beads were filtered off, washed thoroughly with washed out demineralized water and dried in a fluidized bed dryer at 80 ° C.

Subsequently, the dried polymer beads are mixed with 0.1 part by weight of a spray-dried MMA / styrene emulsion polymer and mixed for about 5 minutes in a fluidized bed dryer.
The MMA / styrene emulsion polymer acting as antistatic agent or flow aid was obtained as follows:

In a 5001 polymerization vessel with heating / cooling jacket equipped with stirrer, reflux condenser and thermometer 80 kg of deionized water, 0.016 kg of 75% sodium diisooctylsulfosuccinat and 0.056 kg sodium peroxodisulfate were introduced and heated to 92 ° C internal temperature. In a second reactor equipped with a stirrer at room temperature was an emulsion of 182.4 kg of methyl methacrylate, 17.6 kg of styrene, 0.080 kg of 2-ethylhexyl thioglycolate in 120 kg of demineralized water containing 0.8 kg of sodium diisooctyl sulfosuccinate and 0.12 kg Sodium peroxodisulfate prepared. This emulsion was metered into the polymerization vessel at a rate of 1.2 kg / minute, which was kept at a polymerization temperature of about 92 ° C. by heating or cooling. After the end of the metering, the contents of the reactor were reheated for 30 minutes at an internal temperature of 92.degree.

Subsequently, the resulting polymer dispersion was spray-dried in a spray tower from Niro, equipped with a spinner disk rotating at 15,000 rpm. The supplied air had a temperature of 180 to 190 ° C; the exiting air had a temperature of 75 to 80 ° C. The dried MMA / styrene copolymer had an average particle size of d ₅₀ = 14 μm.

The VZ of the spray-dried MMA / styrene copolymer was 97 cm ³ / g.

The spray-dried MMA / styrene copolymer was mixed at a concentration of 0.1% by weight with the MMA / styrene / N-cyclohexylmaleimide in a fluid bed dryer at room temperature for 5 minutes as described above.

In this case, 510 kg of polymer beads having a viscosity number according to DIN 7745 of 101 cm ³ / g, a residual methyl methacrylate content of 0.47 wt.% And a mean grain diameter of 0.75 mm were obtained. The residual styrene content was below the detection limit of 0.05 wt .-%. The residual N-cyclohexylmaleimide content was below the detection limit of 0.1% by weight.

The additive was added at a level of 0.77 weight percent, based on the total amount of the polyester / additive polymer blend removed by the extruder-fed spinning system. The total amount of polymer blend removed was defined by the number of spinning pumps operated in the spinning system described below and by the throughput of the respective spin pump. When all the spinning pumps were in operation, a total of 304.5 kg / h of polymer mixture was removed from the spinning system and the additive was gravimetrically metered into the extruder feed at a rate of 2.34 kg / h.

Already in the extruder feed, the wave movement of the extruder screw led to premixing of the additive beads with the polyester chips. The polyester chips and the additive beads were melted together in the extruder, an LTM-24D / B8 spider extruder from Barmag AG, Remscheidt / DE, and mixed. This first polymer mixture was discharged at a temperature of 290 ° C at a pressure of 180 bar, conveyed as a melt flow of 304.5 kg / h through the melt line and subjected to filtration with a 20 micron filter cartridge.

The filtered first polymer mixture was fed to a SMX type static mixer from Sulzer AG with an internal diameter of 52.5 mm and a length of 525 mm, where it was homogenized and dispersed to give a second polymer mixture.

This second polymer blend was distributed by product line to twelve spinning positions per position containing six tow packages, with the mean residence time of the second polymer blend from the static mixer exit to the spin pack entering five minutes. Each spin pack contained a round die with 34 holes of 0.25 mm diameter and twice the diameter. The spin pack contained above the nozzle plate, a spin filter package consisting of a steel sand packing of 30 mm height and a grain size of 0.5 to 0.85 mm, and a mesh of 40 microns and a steel fleece filter of 20 microns pore diameter. The diameter of the spin filter pack was 85 mm. The residence time of the melt in the filter pack was about 1.5 minutes. The heating of the spin pack was set to 290 ° C. The surface of the spinneret was 30 mm above the boundary of the heating box. The throughput of the melt mixture resulted in a nozzle pressure of 150 bar. The average residence time of the polymer mixture of polyester and additive melt from the extruder outlet to the exit from the spin packs was about ten minutes.

The molten-filaments extruded from the nozzle holes were cooled by means of blowing air flowing horizontally to the yarn path at a speed of 0.55 m / s and a temperature of 18 ° C and bundled at a distance of 1250 mm from the nozzle plate in an oiler stone to the yarn and with spin finish coated.

A pair of godets looped in an S-shape withdrew the yarn at a speed of 5000 m / min, with a spinning delay ratio of 141 being set.

Between the godets, a swirling nozzle, which was closed when the thread was running normally, was installed, which impressed the thread with a swirling knot number of 13 knots / m with an air pressure of 4.5 bar. The inlet tension in the inlet of the swirling nozzle was set to 0.16 g / den. In each case six threads of a spinning position were wound in a winder into winding packages, wherein the coil speed of 4985 m / min was selected such that the thread tension before winding was 0.1 g / den. Preoriented (POY) filaments were obtained, characterized by a titer of 126 denier, an elongation at break of 116% and a tear strength of 2.4 g / denier.

During the production period of seven days, the breakage rate during operation of the spinning system averaged 0.75 breaks per tonne of polymer blend passed through.

The obtained POYs were stretch-texturized with a texturing machine of the type FK6 from Barmag AG / Germany at a speed of 900 m / min. The draw ratio was set at 1.77 and heater temperatures 1 and 2 at 210 and 170 ° C, respectively. The breakage rate averaged 21 breaks per ton of textured chamois. The textured yarn had a denier of 74 denier, a tenacity of 4.5 g / den, an elongation at break of 18.3% and was characterized by a good staining uniformity.

Example according to the invention

Again, the spinning system described in the comparative example was used at the same throughputs and spinning conditions. In the example according to the invention, an additive consisting of 89.2% by weight of methyl methacrylate, 8.8% by weight of styrene and 2% by weight of N-cyclohexylmaleimide was likewise used, the terpolymer having a viscosity number VZ of about 101 cm ³ / g had. In difference however, as Comparative Example 1 above, an MMA / styrene / N-cyclohexylmaleimide additive obtained by multiple initiation was obtained as follows.

In a 10001 heating / cooling jacket equipped with stirrer, reflux condenser and thermometer, a mixture of 525 kg deionized water, 0.071 kg KHSO ₄ and 13 kg of a 13 percent aqueous solution of a polyacrylic acid was heated to 40 ° C. 525 kg of a mixture of 88.68 parts by weight of methyl methacrylate (MMA), 8.75 parts by weight of styrene, 1.99 parts by weight of N-cyclohexylmaleimide, 0.14 part by weight of 2-ethylhexyl thioglycolate, 0.09 part by weight of t-dodecylmercaptan were then added with stirring. 0.05 parts by weight of stearic acid, 0.2 parts by weight of dilauroyl peroxide and 0.1 parts by weight of tert. Amylperoxy-2-ethylhexanoate added. The batch was polymerized for 115 minutes at 80 ° C and 60 minutes at 98 ° C and then cooled to room temperature. The polymer beads were filtered off, washed thoroughly with demineralized water and dried in a fluid bed dryer at 80 ° C. Then, the dried polymer beads were added with 0.1 part by weight of a spray-dried MMA / styrene emulsion polymer, the synthesis of which is described hereinabove in the comparative example, and mixed for about five minutes in the fluidized bed dryer.

There were obtained 513 kg of polymer beads having a viscosity number according to DIN 7745 of 101 cm ^{3 /} g, a residual methyl methacrylate content of 0.22 wt .-% and an average grain diameter of 0.75 mm. The residual styrene content was below the detection limit of 0.05 wt .-%. The residual N-cyclohexylmaleimide content was below the detection limit of 0.1% by weight.

The additive from the inventive example thus had a comparable bead size and treatment with MMA / styrene emulsion polymer in a fluidized bed dryer a significantly lower residual monomer content compared to the additive of the comparative example.

The additive was added in an amount of 0.77% by weight, based on the total amount of the polymer mixture fed to the spinning system, and the polymer mixture was spun analogously to the comparative example. Again POY yarns were produced during a production period of seven days, characterized by a titer of 126 denier, an elongation at break of 117% and a breaking strength of 2.4 g / den. The breakage rate during operation of the spinning system was on average 0.35 fractions per ton of interspersed polymeimischung.

The POYs were stretch-texturized analogously to the comparative example at a speed of 900 m / min. The breakage rate was an average of 18 breaks per ton of textured yarn. The textured yarn has the same titer and the same tear strength as the textured yarn of the comparative example and an elongation at break of 18.6% with uniform dye uniformity.

Claims (14)

1. Procedure for the manufacture of synthetic filaments from a mixed-compound melt based upon fibre-forming matrix-polymers in the course of which procedure at least one second amorphous additive-polymer which is incompatible with the fibre-forming matrix-polymer is added in a quantity of between 0.05 and 5% by weight with respect to the total weight of fibre-forming matrix polymer and the additive-polymer which is incompatible with it, such that the additive-polymer has a glass transition temperature higher than 100°C and can be processed in a thermo-plastic manner and where the ratio of the melt viscosity of the additive-polymer to the melt viscosity of the fibre-forming matrix-polymer lies between 1: 11 and 10:1 (the melt viscosity is extrapolated to a zero measurement time and determined at an oscillation rate of 2.4 Hz and at a temperature which is 34 degrees C above the melt temperature of the matrix polymer) characterised in that an additive-polymer is used which can be obtained by multiple initiation.
2. Procedure according to claim 1, characterised in that the additive-polymer which is added to the matrix-polymer is obtainable by radical polymerisation in the presence of a mixture comprising at least two initiators with graduated half-lives.
3. Procedure according to claim 1 or claim 2, characterised in that the additive-polymer which is added to the fibre-forming matrix-polymer has a residual monomer content of less than 0.62% by weight with respect to the total weight of the additive - polymer.
4. Procedure according to one of the preceding claims, characterised in that the additive-polymer added to the fibre-forming matrix-polymer has a residual monomer content of less than 0.47% by weight with respect to the total weight of the additive-polymer.
5. Procedure according to one of the preceding claims, characterised in that one or more polyesters may be used as the fibre-forming matrix polymer.
6. Procedure according to claim 5, characterised in that polyethyleneterephthalate (PET), polytrimethyleneterephthalate (PTMT) and / or polybutyleneterephthalate (PBT) is/are used as the fibre-forming matrix-polymer.
7. Procedure according to one of the preceding claims, characterised in that the additive-polymer used consists of one or more polymers which are obtained by polymerisation of monomers having the general Formula I.

   

   
   where R¹ and R² - independently of one another, and whether the same or different - signify a substituent or substituents containing the optional atoms of C, H, O, S, P and halogens atoms such that the sum of the molecular weights of R¹ and R² amounts to at least 40 Daltons.
8. Procedure according to claim 7, characterised in that polymethylmethacrylate and/or polystyrene is/are used as the additive-polymer.
9. Procedure according to one or more of the preceding claims, characterised in that the additive-polymer used consists of one or more polymers which is / are obtainable from the co-polymerisation of
   E = 30 to 99 % by weight of monomers selected from the group consisting of acrylic acid, methacrylic acid and compounds of the general formula CH₂ = CR-COOR¹ where R is a hydrogen atom or a CH₃- group and R¹ is a C₁-C₁₅-alkyl residue or a C₅-C_12-cyclo-alkyl residue or a C₆-C₁₄-aryl residue with if applicable

   F = 0 to 50% by weight of monomers selected from the group consisting of styrene and C_1-3-alkyl-substituted styrenes,
   with

   G = 0-50% by weight of monomers selected from the group of compounds having the Formulae I, II and III

   

   where R³, R⁴ and R5 are respectively a hydrogen-atom, a C_1-15 -alkyl residue, a C_5-12- cyclo-alkyl residue or a C_6-14-aryl residue
   with if applicable

   H = 0 - 50% by weight of one or more ethylenically unsaturated co-polymers which are capable of being co-polymerised with E and / or F and / or G selected from the group consisting of α- methylstyrene, vinylacetate, acrylic acid esters, methacrylic acid esters which differ from E, acrylonitrile, acrylamide, methacrylamide, vinylchloride, vinylidenechloride, halogen-substituted styrenes, vinyl ethers, isopropyl ethers and dienes

   
   where the sum of the weights of E, F, G and H constitutes 100% by weight of the polymerisable monomers.
10. Procedure according to claim 9, characterised in that a ter-polymer consisting of methylmethacrylate, styrene and N-cyclohexylmaleinimide is used.
11. Synthetic filament obtainable by a procedure in accordance with one of the preceding claims.
12. Subsequent processing of the synthetic filament in accordance with claim 11 in a stretching or stretch-texturizing process.
13. Use of the synthetic filament according to claim 11 for the manufacture of staple fibres.
14. Use of the synthetic filament according to claim 11 as technical yarn.