DE1218109B - Manufacture of threads from polymerized caprolactam - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY GERMAN #W PATENTAMT Int. CL:

DOIf

SLEGESCHRIFT 1218109 C08L 77/00

German KI =: 29 b -3/60

Number:
File number:
Registration date:
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2Z / / ö

1218109
Z7781IVc / 29b
January 29, 1960
June 2, 1966

It is known to continuously polymerize caprolactam with the addition of small amounts of water and acid, and it is also known to use solid polymer in the form of powder or chips to melt and spin continuously.

The connection of continuous polymerisation with, which is obvious for economic reasons The immediately subsequent spinning of the polymer turned out to be the production of endless textiles Threads so far as impracticable. The reason for this is that the polymer during spinning has too high a content of low molecular weight substances that still come from the spun thread sweat out after stretching.

In order to obtain a technologically high-quality product, the proportion of the low molecular weight Compounds whose content in the polymer is determined by the so-called water-soluble extract will be lowered considerably after the polymerization.

In order to obtain threads of useful strength and elasticity from the polymer, the proportion of low molecular weight in the spun fiber should not be more than 2 ^fl / o.

It is known, for this purpose, to use the polymer in finely divided form, for example as a schnitzel, to extract with water or the low molecular weight substances from the melt in a vacuum, if necessary to be distilled off with the aid of inert gases such as nitrogen, carbon dioxide or water vapor. Are chips treated in this way melted again or is one in the described Wise extracted melt exposed to higher temperatures, e.g. B. when spinning, it turns out the equilibrium between high and low molecular weight substances in the melt after a short time back on, and the extract content rises again. It has therefore already been tried, through special Shaping the spinning head to keep the residence time of the extracted polymer as short as possible.

With the known methods it was only possible to produce endless textile threads of relatively less To generate viscosity and correspondingly lower strength values. Besides, it had to be finished Fiber material can still be washed before final processing into finished products to reduce the proportion of interfering low molecular weight components to the permissible level. That is also the case with a known method in which the polymer after evacuation or the Melting washed schnitzel in the molten state for some time at a temperature

Manufacture of threads from polymerized
Caprolactam

Applicant:

Hans J. Zimmer Process Engineering,

Frankfurt / M., Borsigallee 1-7

Named as inventor:

Hans Joachim Zimmer f,

Frankfurt / M .;

Dr. Dietrich Natus, Koenigstein (Taunus);

Hans-F. Geisler, Kronberg (Taunus);

Helmut Langanke, Offenbach / M.

stored on the door, · which is only slightly above the melting point of the product lies and wherein the melt, only in the spinning device to the required

as. Spinning temperature is brought.

The subject of the invention is a method for producing threads from polymerized caprolactam by melt spinning a melt, its content of water-soluble low molecular weight compounds reduced by vacuum treatment of the melt as usual, and that again for 0.5 to 6 hours Heated 240 to 280 ° C, subjected to a further vacuum treatment at a pressure below 1 Torr and which lingered for 0.5 to 2.5 hours until the melt emerged from the spinning stations. That The method according to the invention is characterized in that the melt prior to spinning repeatedly exposed to the alternation of vacuum treatment and thermal treatment is.

According to the invention are for the production of the desired fibers with a low extract content at least two vacuum treatments with subsequent thermal treatment required, The last thermal treatment is expediently supplemented and concluded by spinning the melt will.

A polymer, which by means of pressure polymerization at pressures of 10 to 30, preferably 20 at, and temperatures of 240 to 300 ° C from molten caprolactam with the addition of small amounts Obtain water and acid in 15-25 hours

609 577/414

usually has a content of 10% of water-soluble extract substances. These sit down again about 70% from monomers and 30% from oligomers.

example 1

Caprolactam is melted at 8O ⁰ C and mixed at the same temperature in a mixer with 0.4% water and 0.6% of adipic acid. This batch is continuously pressed by a piston pump into a pipe coil, in which it remains under a pressure of 20 atm at a temperature of about 256 ° C for 18 hours. The polymer has a relative solution viscosity in sulfuric acid of 2.0, still contains water of polymerization and consists of 90% polymers and about 6% monomers and 4% oligomers. From the polymerization, the product is fed directly to a vacuum thin-film evaporator via a screw pump. In the first vacuum treatment at an average temperature of 260 ° C., a dwell time of 30 minutes and a vacuum of 0.4 Torr, water, monomer and oligomer distill off.

After that, the viscosity has already risen to around 2.3. The polymer is practically anhydrous and still contains 1.8% extract, 95% of which consists of oligomers. Now the melt for 4 hours in a 26O ⁰ C until heated to 250 intermediate vessel is maintained. Above the melting level, N _{2 is} blown in for flushing, which emerges laden with monomer vapors into a condenser. In this first thermal treatment, post-polymerization takes place, which at the end of the residence time leads to a viscosity of 2.5 with an extract content of about 4% (60% monomer, 40% oligomer). The second vacuum treatment for about 30 minutes. 0.3 Torr und.250 to 26O ⁰ C reduces the extract content to about 1.5%. This. The extract consists almost entirely of oligomers. The product is anhydrous. At 2.5 to 2.6, the viscosity corresponds exactly to the concentration of the stabilizing acid and remains constant during the second thermal treatment.

For this purpose, the polymer remains in for about 1 hour the pipes and the spinning head at a temperature of 260 ° C and is then at Temperature spun. The filament produced has 2.1% extract with the usual ratio of Monomer cream to monomer. The polymer is particularly homogeneous and has a favorable molecular weight Weight distribution. The threads produced from the polymer are easy to draw and yield Breaking strengths of 6.2 g / den with 26% elongation at break. It was crimped yarn of the Titers 70/30 den.

Example 2

For the production of cord silk of the highest strength through direct spinning of continuously polymerized caprolactam is proceeded essentially according to Example 1 with the following differences:

The polymerization approach consists of caprolactam with 0.4% water and 0.3% acetic acid. The polymer has 10% extract of normal composition and a viscosity of 2.8 increasing to 3.0 after the first vacuum treatment during the extract content drops to 1.8% and then consists predominantly of oligomers. At the first thermal Treatment of 2 hours, the content of water-soluble extracts increases again to 3.5% at. The extract has the normal composition of 60% monomer and 40% oligomer. To the second vacuum treatment under the conditions of the first example, the viscosity is at an extract content of around 1.5% reaches a stable value of 3.2. After the one with the spinning process associated second thermal treatment was a low-extract (about 2%) and in their Properties obtained very even corduroy from 840/140 den, which stretch excellently and had the desired textile values of 8.6 g / denier at 14 to 16% elongation at break.

Claims (1)

Claim: Process for the manufacture of filaments from polymerized caprolactam by melt spinning a melt, whose content of water-soluble low molecular weight compounds by vacuum treatment the melt is reduced as usual, and again 0.5 to 6 hours aul 240 to Heated 280 ° C, subjected to a "further vacuum treatment at a pressure below 1 Torr and which remained for 0.5 to 2.5 hours until the melt emerged from the spinning positions, characterized in that the melt is repeatedly alternated between a vacuum treatment and a prior to spinning exposed to thermal treatment. Considered publications:
German patent specification No. 887 691.