JPS6025523B2 - How to clean spinning equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for cleaning and regenerating a yarn machine used for melt spinning thermoplastic synthetic fibers.

Generally, as thermoplastic synthetic polymers are melt-spun, the pressure inside the spinning device, especially the pack, increases, or the spinning process becomes malfunctioning, making it necessary to replace the spinning device. The used spinning equipment that has been replaced is cleaned and reused. As this cleaning method, so-called salt cleaning is usually carried out industrially, which involves immersion in a high-temperature (300 to 600 oo) molten solution of a mixture of sodium or potassium nitrate and nitrite.

However, since such salt cleaning is an oxidation reaction of organic matter by nitrate, the reaction is violent and there is always a danger of flame or explosion.

Further, during this washing, carbonates with a high melting point are generated, and it is necessary to periodically remove them. Removal of this carbonate is extremely dangerous, and the removed carbonate coexists with nitrates and nitrites, so it cannot be easily disposed of as a pollution control measure. In addition, in such salt cleaning, it was extremely difficult to thoroughly clean the threads because the carbides of the polymer and solid matter generated by reactions of various metal salts contained in the polymer stuck to the threading device. .

Therefore, it was necessary to repeatedly perform salt cleaning, and after cleaning, remove the stuck substances with a metal needle while observing with a microscope.

Repeating salt washing in this way and then removing adhered substances using a microscope is not only extremely uneconomical in terms of labor, resources, and energy, but also undesirable in terms of occupational health. The present inventor has arrived at the present invention as a result of intensive research into a method for completely cleaning and regenerating the metal needle without salt cleaning or cleaning the metal needle using a microscope.

That is, in the present invention, a spinning device used for melting a thermoplastic synthetic polymer is heated to carbonize the deposits on the device, and then immersed in an aqueous sulfamic acid solution, and then alkali metal carbonate and/or Alternatively, there is a method for cleaning a bush thread device, which is characterized by immersion treatment in an aqueous solution of bicarbonate of an alkali metal.

In the present invention, the term "grading device" refers to all the spinnerets and pack parts used for melt-spinning thermoplastic synthetic polymers, and it is preferable to disassemble them and use them for cleaning.

In addition, the thermoplastic synthetic polymer referred to herein refers to a polymer that is used to make melt-grade yarn, and in particular, linear polyester polymers such as polyethylene terephthalate, polyamide polymers,
The main target is polyolefin polymers. The first treatment, heating, is to carbonize the polymer component adhering to the grader, and the heating temperature varies depending on the type and amount of the adhering polymer, but is usually 350 oo or higher, preferably It is 400oo or more.

Specifically, the polymer component It may also burn itself. The concentration of the sulfamic acid aqueous solution used in the second treatment is usually 1% by weight or more, preferably 5% by weight.
This is the above, and there is no particular upper limit, and there is no problem even if the saturation state is exceeded.

The treatment time is preferably about 1 inch or more, and preferably 60 to 200 minutes. The temperature of the treatment liquid may be lower than the decomposition temperature of sulfamic acid, and is usually in the range of 5 to 5,000 qo, preferably 20 to 40 qo, and room temperature is sufficient. Therefore, after the heat treatment, it is preferable to cool down to about 50 oo or less and then immerse it in an aqueous sulfamic acid solution.After the first treatment, it may be washed with water and then subjected to the second treatment. During this immersion, the liquid may be immersed by using a dipping machine, aeration, or moving the cap pack. The alkali metal carbonate or bicarbonate used in the third treatment includes:
Specifically, they include sodium carbonate, potassium carbonate, lithium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, and lithium hydrogen carbonate, and these may be used alone or in combination of two or more.

The concentration of the (bi)carbonate may be within a very wide range as long as it reacts with the sulfamic acid attached to the die pack to be diluted and foams. For example, a content of 2 to 1% by weight can sufficiently achieve the purpose.
The treatment temperature may be arbitrary, and room temperature is sufficient. A considerable amount of carbide and other fixed substances are attached to the first heat-treated yarn device, and a large amount is especially attached to the inside of the pores of the spinneret.

By immersing this in a second sulfamic acid aqueous solution, the sulfamic acid penetrates between the stuck material and the vessel wall, and most of the stuck material is removed. However, there are some fixed substances left inside the pongee holes and in parts with complicated structures, but these residues are in a state where they are extremely easy to be removed by sulfamic acid. In paper yarn devices treated with an aqueous sulfamic acid solution, the sulfamic acid has penetrated between the remaining adherents and the vessel wall, and the sulfamic acid has penetrated into the holes and parts with complicated structures. Aqueous solution is retained. Therefore, when such a yarn device is immersed in a third alkali metal (bi)carbonate aqueous solution, carbon dioxide gas is instantly foamed due to the acid-base neutralization reaction, and the stuck substances remaining in the spinning device are removed. is completely removed. By sequentially performing the first to third treatments in this manner, the spinning apparatus is completely cleaned.

The twill yarn device after the third treatment can be reused as is by washing with water and drying. Any method can be used for this water washing. The spinning device may be submerged in water, and at this time, worship may be performed using a nada device, aeration, or the like. Furthermore, water may be ejected, or steam may be ejected instead of water. In particular, it is preferable to inject steam because even if there is any residue, it will be removed by this injection. Also,
Drying can also be carried out by any method, such as drying by heat, natural drying, drying by compressed air spraying, etc. According to the method of the present invention, the spinneret pack can be completely cleaned and regenerated without salt cleaning or metal needle cleaning by microscopic observation, and the work efficiency required for regeneration can be greatly improved. Defects in the spinning process due to defects,
For example, it is possible to improve the bending of the yarn on the spinneret surface, the occurrence of wrapping or yarn breakage in the weaving process or the stretching process, the occurrence of fuzz, etc.

The present invention will be explained in further detail by giving examples below.

Example 1 A spinning pack used for melt spinning polyethylene terephthalate was disassembled.

The cap was made of SUS 316 stainless steel, with a diameter of 17 m, a thickness of 1 m, 96 holes, and a hole diameter of 0.3, and the other pack parts were made of SUS 304 stainless steel. The disassembled cap and pack parts were placed in an electric furnace and heated at 600°C for 4 hours, then taken out, cooled, and immersed in a 1% by weight sulfamic acid aqueous solution at 40°C for 3 hours, so that the sulfamic acid aqueous solution adhered In this state, it was immersed in a 5% by weight aqueous sodium carbonate solution at room temperature for 1 minute. Foaming occurred simultaneously with erosion. After soaking the bond, take it out, wash it with water, and apply 3k9/5g of steam.
It was sprayed for a minute and then dried by blowing with compressed air. The pack parts were thoroughly cleaned and no deposits remained. Furthermore, when the cap was observed under a microscope, it was found that it had been completely cleaned, with no holes in which any solid matter remained.
Example 2 The cap and pack parts, which had been heat-treated in an electric furnace and cooled in the same manner as in Example 1, were immersed in a 15% by weight aqueous solution of sulfamic acid at 40 C for 2 hours, followed by 1% by weight potassium bicarbonate at room temperature. Soaked in aqueous solution for 2 minutes.

After taking it out and washing it with water, it was dried by blowing compressed air. cap,
All pack parts were thoroughly cleaned. Comparative Example The same disassembled cap and pack parts with paper thread as in Example 1 were mixed with 6% by weight of sodium nitrate and 35% by weight of sodium nitrite.
and 40,000 mol of 5% by weight of sodium hydroxide.

As soon as the tank was immersed, a fierce flame erupted and the salt was blown up, almost spilling over. After soaking for 5 minutes, it was washed with water and dried using compressed air.

Claims (1)

[Claims] 1. A spinning device used for melt spinning a thermoplastic synthetic polymer is heated to carbonize the deposits on the device, and then immersed in an aqueous sulfamic acid solution, and then treated with an alkali metal carbonate and/or Or, a method for cleaning a spinning device, which comprises immersing it in an aqueous solution of an alkali metal bicarbonate. 2. The method for cleaning a spinning device according to claim 1, wherein the concentration of the sulfamic acid aqueous solution is 1% by weight or more. 3. The method for cleaning a spinning device according to claim 1 or 2, which comprises treating with an aqueous solution of alkali metal carbonate and/or alkali metal bicarbonate and then further treating with steam. 4 The thermoplastic synthetic polymer is a linear polyester polymer,
The method for cleaning a spinning device according to any one of claims 1 to 3, wherein the cleaning method is at least one thermoplastic synthetic polymer selected from the group consisting of polyamide polymers and polyolefin polymers.