DE1660289B2 - Process for removing monomers and low molecular weight fractions from polyamide threads, fibers or wires - Google Patents

Description

holds, treated at 162 ° C. ^{300 m 3 of} gas mixture is passed through 1 kg of fiber, thereby achieving the following:

% Total extract% monomer
Before! Treatment: 4.4 1.1

After gas treatment: 3.1 0.14

Example 2

Fiber material made of polycaprolactam with a single titer of 6 denier is treated with a mixture of air and water vapor containing 10% water vapor at 161 ° C. ^{1000 m 3 of} gas mixture are passed through the 1 kg of fiber. The result is as follows:

% Total extract% monomer Before treatment: 4.4 1.1

After gas treatment: 2.9 0.04

Example 3

Fiber material made of polycaprolactam with a single titer of 15 denier is treated with a mixture of air and water vapor containing 20% water vapor at 165.degree. ^{1500 m 3 of} gas mixture are used per kg of fiber material. The following result is obtained:

Before treatment:
After treatment:

% Total extract 2.4 x 1.7

, Monomer 0.15 0.02

Claims (4)

ethanol, ethanol, isopropyl alcohol, acetone, claims: methylene chloride, benzene, chlorobenzene, gasoline, wash or extract. Also through 1. Process for removing monomers Heating in vacuo can at least be and low molecular weight fractions of polyamide 5 structures with a large surface, in particular threads, -fibers or wires through thermal dere rayon, a large part of the lactam treatment these evaporate at higher temperatures. half 100 ° C and below the softening point of the polyamides; that the thermal treatment in part because of the immediate onset of regression Presence of a mixture of superheated low polymer and monomer "· from the Steam and inert gases take place. purified polycaprolactam in the coat 2. The method according to claim 1, characterized in turn low-polymer finished products and that the mixture of superheated nomere substances contain the amount thereof from water vapor and inert gases 80 to 9O ⁿ / o to * 5 depends on how long the polyamide melt before the Contains inert gases. spin was kept at the melting temperature. the Treatment according to items 3 and 4 has the disadvantage that the washed finished product is then which has to be dried and re-prepared. the the method mentioned under point 4 does not only deviate from the method of the invention described below, but is obviously limited The invention relates to a method for removal applicable to structures with the largest possible surface aation of monomers and low molecular weight surface. share from polyamide threads, fibers or wires 25 The invention is based on the object to provide by thermal treatment of the same in Tempe processes, which the aforementioned fatures above 100 "C and below the expansion does not have disadvantages and with the help of which one point of the polyamides. Threads, fibers, wires and bristles made of polyamide At the Polymerisatici of Lactamen it is possible to produce the so few low polymers and runs the conversion partly incomplete, z. B. will contain 3 ° caprolactam that further processing 100% caprolactam used, only 90% in poly- runs completely trouble-free. caprolactam converted. ^{The remaining 10 n} / o This task is achieved according to the invention with a consist of low-polymer substances and mono- Processes for removing monomers and low meren. These substances interfere with the further processing of the molecular components of polyamide threads and fibers processing of the finished products, in particular interferes with 35 or wires due to thermal treatment of the the monomer. The monomeric caprolactam diffuses at temperatures above 100 ° C and below dated to the surface during storage, thus reducing the softening point of the polyamides through creates a sticky or rough fiber, that solved the thermal treatment in the presence Wire or bristle surface. To this un- a mixture of superheated steam and desired appearance that the further processing takes place 4 ° inert gases. makes it very difficult or impossible to eliminate. In a preferred embodiment, the you can go different ways. Fol-thermal treatment with a gas mixture is known low: 10 to 20 ° / ₀ of superheated steam and 80 to 90 ⁰ O containing inert gases. 1. The polyamide chips, originating from a ₄₅ As inert gases you can z. B. nitrogen, carbon equilibrium polymerisatior, are used before $ \ o \\ & or air. For the effectiveness of spinning by a wash of the _th e _se r treatment, it is immaterial whether the material low polymer and monomer substandard j _e h _nac manufacturing process more or less Restzen freed. contains monomeric and low polymer substances. the 2. Before spinning, for example, 5 ° thermal treatment is carried out at temperatures of between the Swiss patent 2Sl 096 see 100 "C and the softening temperature of the from the melt through a vacuum hand polyamide, preferably between 150 and 200 ° C, treatment or by treatment with inert. gas low polymer and monomeric sub- The process according to the invention is based on punch away. ^{55 of} the following examples. ,., .. ,, ··. ·, _, ·. ■ The total extract given in the examples _{3. Washing is carried out,} for example, according to the Austrian method determined by exhaustive extraction of the patent _{specification 175,965 from the polymer with hot} methanol. This extract demolded structures made of polyamide after the _hä , / _{the lower} oligomers and dimers of the Ca spmn process, the undesirable persistence of _{6o prolactams and} monomers. The monomer will ^eraus - isolated from the methanol extract. 4. For removal and recovery mono-. .
Merer lactams can be obtained according to the doctrine of B e 1 s ρ 1 e 1 1 German patent specification 970 066 the threads, In a drying cabinet with perforated drum Foils, ribbons in front of or usually more useful 65 mine, over which the fiber strand is passed: is, is after stretching with lactam-dissolving co-fiber material made of polycaprolactam with the single tel, z. B. water or aqueous solutions titer 6 with a r. Mixture of air and or organic solvents, such as heated water vapor, the 10% water vapor