JPS6031925B2 - Manufacturing method of composite fiber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention involves dissolving or dispersing an inert gas or an inert foam material in the melt of a synthetic polymer before spinning, so that one component is Composite fibers with a large number of coexisting interrupted cavities
This invention relates to a method for producing rconju tedfi skin.

In such known processes, it is only possible to induce foaming in the core of the fibers to be formed by special temperature conditions below the paper thread nozzle, and the foaming process is stopped in the jacket zone by cooling. .

The resulting fibers are impermeable and have a jacket that tightly surrounds an elongated, hollow, penetrating core after drawing the entire weave. The disadvantages of this known method are, firstly, the fact that only extremely precise temperature control results in a bicomponent structure (with a crimped core and an uncrimped jacket). Insufficient cooling results in fully expanded fibers with a monocomponent structure, ie simple foam fibers. Secondly, this known method, in addition to core-jacket structures with a foamed core, can also be applied to other industrially important two-component structures, such as core-jacket structures with a solid core and a foamed jacket (this (the wick can also have an eccentric position relative to the fiber rattan) or it is not possible to create a side-by-side structure. The known methods therefore also make it impossible to produce crimpable two-component structures. The object of the invention is to eliminate the disadvantages of this known method.

Particularly strong crimping at low weight and significant strength
Composite fibers with properties should be produced. In this case, the production method should be simple and reliable, and in particular when spinning the fibers, the fibers should also have a coiling property. This task consists of dividing the melt of the synthetic polymer according to the invention in the method described at the outset and subsequently adding silicone oil and oil to one sub-stream of the melt with up to 1% by weight of silicone oil, based on the weight of the melt of this sub-stream. An inert gas or an inert foaming material is added in an amount where the volume of gas is 10% relative to the weight of the melt in this branch.
% and then feeding the split streams separately to one two-component spinning head. By incorporating silicone oil, the threadability of the polymer is significantly improved, the operating time of the spinning nozzle is significantly increased, and above all it is ensured that the cavities are evenly distributed and have a diameter within a relatively narrow range. Ru.

The fibers produced according to the invention may, within defined ranges,
having a circular cross-section in the main body, generally having a diameter of about 0.5 to 6 degrees, in high fineness up to about 10 degrees or more, coexisting or one after the other; It has numerous cavities that are approximately needle-shaped in the stretched state. The incorporation of silicone oil and blowing agent preferably takes place between a pressure pump assisted by the melting device and a metering or paper thread pump upstream of the grade thread head, in which case the melt pressure is preferably 50. ~200 bar, especially between 80 and 16 bar. 0.1 to 0.4 relative to the weight of the melt in the split stream
It has proven particularly advantageous to incorporate % by weight of silicone oil. The process of the present invention can be practiced with virtually any fiber-forming polymer, such as nylon 60, polyethylene terephthalate or its copolymers, polypropylene or other polyolefins.

When polyethylene terephthalate is used, silicone oil is mixed in an amount of 0.1-0.3% by weight based on the weight of the brood liquid in the split stream, and when polycaprolactam is used, 0.2-0% silicone oil is mixed in based on the weight of the brood liquid in the split stream. .4% by weight of silicone oil is mixed in. Among the commercially available silicone oils, those with a viscosity of 3 to 40 ratio P (at 20° C.) have proven suitable for carrying out the process of the invention. It was done.

Particularly preferred are unstabilized silicone oils with a viscosity of 3 to 5 P (at 2000); silicone oils with higher viscosities are preferably not stabilized with known stabilizers, for example cerium compounds. No. The silicone oil can contain nucleating agents that are common in their own right, such as finely divided titanium dioxide, kaolin, talc, and the like.

The amount of gas mixed into the melt can be varied within relatively narrow limits.

However, care should be taken to ensure that the gas and melt are combined under conditions such that the gas is mostly dissolved in the melt or is only finely dispersed. The important melt conditions in this case are mainly temperature and pressure. By increasing the amount of gas mixed, the density of the resulting aggregate decreases. In this way, the density of the resulting fibers can therefore be varied within a relatively wide range by adjusting the loading.
The amount of gas added can be varied, for example, by varying the pressure at which the gas is introduced into the melt, or by the pressure or residence time of the melt at the gas supply point. The density of the fibers can also be varied by using different gases.

Another method of varying the density of the fibers consists in using a mixture of two or more gases as inert gas, varying the content of the individual gases in the gas mixture. Therefore, in a particularly simple way, one only changes the content of one gas in the metered gas mixture, keeping all other conditions constant such as pressure, temperature, feed rate, residence time in the mixer, etc. A specific density can be obtained by this. For example, it is very advantageous to use a carbon dioxide/nitrogen mixture to set the appropriate density. Moreover, two or more types of gas can also be supplied at locations located before and after each other. Particularly suitable blowing agents are organic solvents.

This blowing agent, as well as the entrained gas, forms cavities in the fiber as the melt exits the spinneret, which is a feature of the invention. Blowing agents include, inter alia, low-fluorescence point hydrocarbons such as pentane or hexane, hydrocarbons which exist in gaseous form at room temperature such as butane, and halogenated hydrocarbons, especially fluorohydrocarbons, such as tetrachlorofluoroethane. Examples include hydrogen. The paper thread conditions are generally the same as for threading a melt without cavities.

Therefore, apart from the silicone oil and blowing agent supply conduits to be replenished and the mixer to be replenished, the conventional paper thread equipment,
In particular, conventional two-component paper thread heads can be used. All composite fibers produced according to the invention can be spun without particular problems and drawn with a slightly lower drawdown than fibers without cavities but with only one component of the same polymer.

The stretching used according to the invention is approximately 1200 M/mi
In the composite fiber drawn at n, the ratio is about 1:3.0 to 1:3.2 for polyethylene terephthalate, and 1:2.5 to 1:2.6 for polycaprolactam. In addition to composite fibers with a circular cross-section, it is also possible with difficulty to produce other cross-sectional shapes, such as rectangular, pentagonal or hexagonal, oval or tripodal cross-sections. The fibers are usually post-treated and can in particular be subjected to a shrinkage treatment which induces latent crimp.

The windability of all composite fibers according to the invention can be significantly improved if the fibers are subjected to an asymmetric heat treatment, for example intense one-sided cooling or heating, immediately after they leave the paper spinneret. The invention will now be explained in more detail with reference to the accompanying drawings: FIG. 1 shows a weaving device for carrying out the method of the invention;
The device initially has the following conventional components: a melting device 1 (in this case an extruder); a brood conduit 2 for supplying the melt to a distribution tube 3;
Melt conduit 4; 5 which sends the melt branch through spinning pump 7:12 to a two-component yarn head 8 where the melt is combined with composite fiber 10 and extruded by a separate yarn nozzle 9; .

In addition to these customary components, the device used according to the invention includes a pressure pump 6, silicone oil and gas for introducing the blowing agent between the distribution pipe 3 and the thread pump 12. Two conduits 13 with control devices 14, 16
;15 (in this case the order of addition is not important) and a mixer 1 which takes care of homogeneous mixing of the silicone oil and the blowing agent, assisted by both these conduits 13:15;
1 is required.

In place of the pressure pump 6, mixer 11 and thread pump 12, as described in the patent application filed today,
A chain mixer connected between two paper thread pumps (
(not shown) can also be used.

Of course, in addition to the incorporation of silicone oil and blowing agent into the melt stream that flows through the melt conduit 4 to the two-component spinning head 8, there is another difference in the brood liquid treatment with respect to the stream guided through the liquid conduit 5. It is also possible to carry out a heat treatment (not shown), for example pyrolysis and thereby causing a shrinkage change.

After the composite fiber 10 has been asymmetrically cooled, stretched and optionally shrunk, it can be wound up (not shown).

Figures 2 to 6 represent composite fibers according to the invention with various cross-sectional shapes and/or component arrangements.

In FIG. 2, a core 18 with a cavity 19, which is a feature of the invention, is surrounded by a conventional solid jacket 17.

Fibers have a smooth surface even when stretched,
The core component has an excellent void ratio of approximately 20%. FIG. 3 shows a fiber according to the invention in which a core 20 located at an offset D is surrounded by a jacket 21 with a cavity 22.

This fiber has good windability. Similarly, the fibers having the side-by-side structure shown in FIG. 4 are extremely crimpable.

A component 25 having a cavity 24 is present next to the component 23 which solidly fills the fiber cross section. Figures 5 and 6 are
In contrast to FIGS. 4 to 4, fibers with a core-jacket structure are shown, in which case the core 26:30 is the cavity 29:33.
It is surrounded by a jacket 27;31 having a.

A part of the cavity 29; 33, as long as it is present on the surface,
The fibers were ruptured during spinning and are now ruptured. These fibers therefore have an open surface structure and thus a linear character. An example of a fiber cross section illustrated in FIG.
It is prismatic (with a round core).

Other cross-sectional shapes, such as triangular, quadrilateral or pentagonal, oval and rectangular shapes, can be produced just as easily. The heterostructure fibers according to the invention have a low density due to the cavities that are characteristic of the invention and many of the advantages found in hollow fibers.

On the other hand, the fibers according to the invention have good threadability and drawability and good high strength due to the void-free polymer content.

[Brief explanation of drawings]

FIG. 1 is a system diagram of a grading device particularly suitable for the production of fibers according to the invention; FIG. 2 is a schematic cross-sectional view of a core-jacket structural fiber according to the invention with a cavity in the core; FIG. FIG. 4 is a schematic cross-sectional view of a side-by-side structural fiber according to the invention, and FIG. 6 is a schematic cross-sectional view of a core-jacket structural fiber according to the invention with partially ruptured cavities in the component; FIG. 6 is a schematic cross-section of a core-jacket structural fiber according to the invention with a hexagonal cross-sectional shape; It is a diagram. 1... Melting device, 6... Pressure pump, 7...
... class thread pump, 8... two-component class thread head,
9... Grade thread cap, 10... Composite fiber,
11...mixer, 12...class thread pump. Second
Figure 3 Figure 4 Figure 5 Figure 1 Figure 6

Claims (1)

[Claims] 1. Before spinning, an inert gas or an inert foaming substance is dissolved or dispersed in the melt of a synthetic polymer so that one component coexists with a large number of components. In a method for producing bicomponent fibers with interrupted cavities, a melt of a synthetic polymer is divided and then one sub-stream of the melt is treated with up to 1% by weight of silicone oil and based on the weight of the melt of this sub-stream. An inert gas or an inert foam material is mixed in under conditions such that the volume of gas is less than 10% relative to the weight of the melt in this split stream, and then the split stream is separately fed into one two-component spinning head. A method for producing a composite fiber characterized by supplying the composite fiber. 2. The method according to claim 1, wherein silicone oil is mixed in an amount of 0.1 to 0.4% by weight based on the weight of the melt in the divided streams. 3. The method according to claim 2, wherein when manufacturing composite fibers made of polyethylene terephrate, 0.1 to 0.3% by weight of silicone oil is mixed with respect to the weight of the split melt. 4. The method according to claim 1, wherein when producing composite fibers made of polycaprolactam, 0.2 to 0.4% by weight of silicone oil is mixed with respect to the weight of the split melt. 5. The method according to any one of claims 1 to 4, wherein the silicone oil has a viscosity of 3 to 400 cP at 20°C. 6. The method of claim 5, wherein the silicone oil is an unstabilized silicone oil having a viscosity of 3 to 50 cP at 20<0>C. 7. A gas or an inert foaming material that is generally inert to the silicone oil and the melt, with a volume of gas that is
7. The method as claimed in claim 1, wherein the incorporation is carried out under conditions such that it is less than 5% relative to the total volume of the melt in the split stream.