JPS6026841B2 - Melt spinning method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for preventing the generation of carbides on the surface of a paper thread cap. This invention relates to a method for preventing the formation of carbides and the adhesion of monomers on the surface of a hollow fiber spinneret by sealing with an inert gas heated to a higher temperature.

Generally, when polymers containing several percent or more of monomer (such as nylon 6) are melted and drawn out during polymerization equilibrium, the monomer vapor that evaporates into the atmosphere along with the polymer that is prevented from the mouth surface comes into contact with the hot mouth surface. Accumulates as carbide,
Particularly, when the carbide generated around the spinneret hole grows to a certain size, it comes into contact with and adheres to the spun yarn, resulting in abnormally shaped yarn, which causes a problem in the quality of the process.

Conventionally, various methods have been tried to prevent the growth of carbides around the mouth surface, but among these methods, there is a method of sealing the mouth surface with an inert gas such as water vapor or nitrogen (Mochikosho-12365). (Japanese Patent Publication No. 44-2116 candy, etc.) are effective in achieving the desired purpose, and methods using water vapor as an inert gas are particularly frequently used.

However, the method of blowing steam has the following drawbacks. In other words, in recent years, the bulkiness of fibers has been increased,
Hollow fibers are often used for purposes such as changing the gloss after dyeing, but when producing these hollow fibers, when the mouth surface is sealed with steam, the steam that penetrates into the fibers cools and solidifies the yarn. This concomitantly causes condensation and the problem of not being able to ensure a sufficient hollowness ratio at all, making the use of steam a decisive drawback for the production of hollow fibers.

On the other hand, in order to ensure the hollowness ratio, a method of blowing nitrogen instead of water vapor is currently being used, but even in this case, various drawbacks arise.

In other words, if a large amount of nitrogen is used with many consecutive spindles, the room will be filled with nitrogen leaking from individual bush knots, creating an oxygen-deficient state and causing poisoning or death to workers around them. This poses a huge problem in terms of safety management, such as accidents. For this reason, when using nitrogen, various safety equipment such as automatic oxygen concentration measurement alarm devices and automatic nitrogen blowout control bags are installed in various parts of the room, but these are also not safe. The amount of capital investment will be extremely high. In addition to this, the price of nitrogen itself is high, so if a large amount of nitrogen is constantly sprayed, the running cost will be very high. The inventors of the present invention have made extensive studies to solve these problems, and have found that it is sufficient to interpose an inert gas between the spinneret surface and the water vapor layer, and have arrived at the present invention. That is, in the present invention, when sealing the lower part of the spinneret with water vapor in a melt-woven yarn of a synthetic polymer, a gas is formed between the spinneret surface and the water vapor layer at room temperature and at a temperature higher than the water vapor temperature. This method is characterized by intervening a heated inert gas.

Synthetic polymers used in the method of the present invention include synthetic polymers capable of melting yarn such as polyester and polyamide, but the effect is particularly remarkable in the case of polyamide.

The figure explains one embodiment of the present invention, and the yarn 2 taken out from the thread cap 1 is cooled and solidified by cooling air or the like in the spinning tube 3 and then taken out. 1
An inert gas blowing slit 4 and a water vapor blowing wire mesh pipe 5 are provided in this order from above between the fishing line tube 3 and the fishing line tube 3.

From the non-trigonal gas blowing slit 4, a non-trigonal gas which is a gas at room temperature and which has been conditioned to a temperature higher than the water vapor temperature is blown onto the surface of the thread cap 1 and covers the surface of the cap. Reference numeral 6 designates a non-triangular gas supply g-groove conduit 7 which is a punching plate for uniformly rectifying the inert gas.

The inert gas blowing slit 4 is designed to blow out the inert gas perpendicularly and in a rectified manner to the yarn 2 ejected from the spinneret 1, and the width of the blowing slit 4 is 2 to 30 mm. The installation position is preferably 10 to 50 skins below the surface of the paper yarn cap 1 and as close to the spun yarn 2 as possible. On the other hand, the water vapor is superheated to 110 to 150q0, passes from the water vapor supply conduit 8 to the water mill blowing wire mesh pipe 5, and is sent to the spinneret 1.
The paper thread cap 1 is supplied to the bottom of the paper thread nozzle 1 to seal it.

Here, the inert gas blown out from the inert gas blowing slit 4 must be a gas at room temperature and must be heated to a higher temperature than water vapor. By making the temperature of the inert gas higher than the water vapor temperature, the inert gas has a lower density than the water vapor and stays on the spinneret surface, preventing the water vapor from coming into contact with the spinneret surface, eliminating the drawbacks of water vapor seals. However, if the temperature of the inert gas is lower than the water vapor temperature, the effects of the present invention cannot be achieved. Also, this inert gas is typically used at a temperature below the molten polymer temperature. The flow rate of the inert gas is preferably 10 to 3 times per hour. In the present invention, it is not necessary to completely block water vapor from the paper thread cap with an inert gas, and it is not necessary to completely block water vapor from the paper thread cap using an inert gas. There is no problem even if it gets mixed in.

In addition, examples of the non-tritonous gas used in the present invention that is gaseous at room temperature include nitrogen, helium, carbon dioxide, and the like.

As described above, according to the present invention, since the paper spinneret surface is always sealed with inert gas and water vapor, it is possible to prevent the generation of carbides and the adhesion of monomers to the spinneret surface. Since the inert gas is interposed between the and the water vapor layer, the water vapor does not come into direct contact with the mouth surface and enter the hollow part of the weaving yarn, reducing the hollowness ratio. When used in combination, the leakage of inert gas into the room is sealed with water vapor, which eliminates safety problems such as indoor oxygen deficiency caused by continuous blow-out of only inert gas such as nitrogen, and reduces capital investment. And running costs can be reduced significantly.

The present invention will be explained in more detail with reference to Examples below.

Examples 1 to 4, Comparative Examples 1 to 2 Nylon 6 hollow fibers having an equilateral triangular cross-sectional shape and three hollow parts therein, paper yarn having sporadic nozzles, and a grade yarn of 250q○ When spinning at high temperature, the spinneret surface was sealed using the apparatus shown in the figure and the yarn was threaded.

That is, an inert gas blowing slit 4 with a width of 5 mm was provided below the three-way cape of the suture extraction nozzle surface, and nitrogen gas was blown out from the slit 4 in a direction perpendicular to the drawn thread 2. Furthermore, steam superheated to 130° C. is blown out at a rate of 100 degrees per minute from a steam blowing wire mesh pipe 5 provided below the slit 4, and cooling air is blown out from a stopper 6 provided below the slit 4 to blow out the discharged yarn. After solidifying, it is rolled up at a take-up speed of 50 minutes, and then
The yarn was drawn 3.4 times to obtain a drawn yarn of 1300 denier.

At that time, the amount of nitrogen gas and nitrogen gas temperature were varied, and the degree of contamination on the surface of the suture nozzle and the cross-sectional shape of the spun yarn were observed, and the results are shown in the following table. * Spinneret fouling time is the time required for carbide or monomer to adhere to the surface of the yarn nozzle and yarn breakage to occur during the spinning process, or for yarn breakage to occur when the spun yarn is drawn. means (day).

As is clear from the table, in Comparative Example 1, in which the surface of the yarn cap was directly sealed with water vapor, the yarn hollowness was low and the deformation of the hollow part was large. In Examples 1 to 4, the yarn hollowness ratio was large and the deformation of the hollow portion was small. In addition, the nitrogen gas temperature is higher than the water vapor temperature.
In Comparative Example 2, where the temperature was lower than 0° C.), there was no water vapor blocking effect, the yarn hollowness was low, and the hollow portion was greatly deformed.

[Brief explanation of drawings]

The figure is a schematic diagram for explaining an embodiment of the present invention.

Claims (1)

[Claims] 1. In melt spinning synthetic polymers, when sealing the lower part of the spinneret with water vapor, an inert gas that is a gas at room temperature and heated to a higher temperature than the water vapor temperature is inserted between the spinneret surface and the water vapor layer. A melt spinning method characterized by intervening.