JPS6075609A - Manufacture of polyester fiber - Google Patents

Abstract

PURPOSE:To obtain the titled uniform fiber, stably, by melt-spinning a thermoplastic polyester polymer through a spinneret, cooling below the glass transition temperature, drawing in a hot zone heated with hot gas introduced actively into the zone at a specific flow rate, and winding at a high speed. CONSTITUTION:A thermoplastic polyester polymer is subjected to the melt spinning through a spinneret, and cooled to a temperature below the glass transition temperature. The obtained yarn Y is transferred through a hot zone to effect the thermal drawing in the zone. In the above process, the heating cylinder 1 is furnished with plural small holes 3 and a hot-gas-supplying part 2 surrounding said holes 3, and the heating zone is heated with the electric heater 4. Hot gas satisfying the formula T>=Tg+10 [T is the temperature of the hot gas ( deg.C), and Tg is the glass transition temperature of the polymer] and the formula 10<= F<=80 [F is flow rate of the hot gas (Nl/min)] is introduced actively into the hot zone, and the yarn is wound at a take-off speed of >=3,000m/min to obtain the objective fiber.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a method for producing polyester fiber. More specifically, I+8! is a polyester fiber that satisfies mechanical PC'iiL+F-no properties that can be used practically in a single spinning process. This relates to a method for RL.

<Prior Art and its Problems> For the purpose of reducing production costs and conserving energy, methods have been proposed for producing polyester fibers in a single process, including a spinning process.

An example of such a method is
As disclosed in the above publication, there is a method in which the melt-spun yarn is once cooled to below the glass transition temperature by kneading and then passed through a heating zone again to achieve hot drawing.

Generally, a heating cylinder whose surroundings are heated is used as the heating zone, but it is not possible to simply heat the area around the heating cylinder to increase the atmospheric temperature inside the heating cylinder and run the yarn. The atmospheric temperature becomes uneven, and the uniformity of the resulting yarn deteriorates, resulting in uneven dyeing when dyed into fabric.

It cannot be used as a product.

In addition, when such a heating cylinder is used, as the take-up speed is increased, the accompanying airflow of the running yarn flows into the heating cylinder, lowering the ambient temperature, making it impossible to perform hot drawing sufficiently, and causing uneven drawing. Therefore, the uniformity of the yarn is reduced.

To overcome these drawbacks and reduce the atmospheric temperature due to accompanying air currents, we have proposed the method of JP-A II/(54-13861).
A method has been proposed, such as in Publication No. 5, in which the yarn is bundled and passed through a heating cylinder while removing the accompanying airflow, but in such a method, the heat treatment efficiency is low because the yarn is bundled. However, the drawback is that high-temperature conditions of as high as 800°C must be used, resulting in high costs.

In addition to the above, there have also been attempts to eliminate the influence of accompanying airflow by dividing the yarn in the heating zone in order to achieve uniform stretching (Japanese Patent Application Laid-Open No. 14761/1983). , an attempt to pass through two heating zones in order to make the deformation of the yarn as slow as possible in the heating zone (Japanese Patent Application Laid-Open No. 160816/1983)
has been proposed, but this method (r) cannot completely remove the influence of accompanying airflow and cannot obtain a sufficiently uniform yarn.

Therefore, in the conventional technology, we have completed the technology to obtain polyester yarn that is low cost and has satisfactory mechanical properties and uniformity by passing it through the JJI + tropical zone in the spinning process at a level that does not cause any operational problems. I'm in a situation where I don't have any.

<Purpose of the Invention> The present inventors made the yarn once cooled in the spinning process pass through the heating zone again and hot-stretch it to obtain mechanical properties that can be used in practical use.
As a result of various studies on methods for manufacturing polyester fibers that satisfy uniformity in one process, we found that heating gas was actively introduced into the heating zone VC and the flow rate of the heating gas was adjusted to an appropriate IE.
The inventors discovered that yarns with satisfactory mechanical properties and uniformity could be stably obtained only by controlling the fibers within a certain range, and this led to the present invention.

<Structure of the Invention> That is, the present invention melt-spun a thermo-OT plastic polynisder polymer from a spinneret, cooled it once to a glass transition of 114 degrees or below, and then heated it again (running the yarn through the fF working area (t
When heating and stretching the yarn in the heating and heating zone, the polyester fiber is taken at a taking rate of 3000+n/dividing soil while actively introducing a gas that satisfies the following conditions into the heating and jib zone. This is a manufacturing method.

Temperature of heated gas ``r(Q T≧Tg+10 Flow rate of heated gas F(N11 minutes (normal liter 10≦F≦80 (where Tg is the glass transition temperature of the polymer) The present invention will be described in more detail below.

The polyester polymer in the present invention is mainly a polyester having ethylene terephthalate as a main repeating unit, but may also be a polyester polymer having petite lenoterephthalate-1 as a repeating unit. Also, 15
It may also be a polyester copolymerized with one or more other components in an amount of less than 10%, and a polyester polymer containing a low Iit additive.

In the present invention, what is important is that while the atmosphere of the heating zone through which the yarn passes after cooling is heated from the surroundings, a heated gas of a specific temperature and a flow of 1i is introduced into the heating zone, and the take-up speed is 5.
1,000m/min.

In particular, it is the boiler/l- of the present invention to introduce the heated gas, and the flow rate of the heated gas is the temperature ITf IB2'')'v)-
(By adopting certain conditions, Itlf l
441 r）
It is possible.

In other words, simply passing the yarn through a heating zone where the surroundings are heated to raise the ambient temperature IW will result in an increase in the take-up speed, especially as the take-up speed increases. However, at speeds above 3000 m/min, the uniformity of the yarn rapidly decreases. However, when heating gas is introduced into the heating zone under certain conditions, the uniformity of the yarn decreases rapidly. It was discovered that it could be suppressed.

At this time, the key point of the present invention is the flow of heated gas introduced into the heating zone; That is, the flow rate of the heated gas is 1
Only when the temperature is 0 to 80 N11 minutes, a yarn with satisfactory mechanical properties and good uniformity can be obtained.

If the flow rate is less than 10 N11 minutes, the uniformity deteriorates, the mechanical properties also deteriorate, and the effect of introducing the heated gas is not fully exhibited. When the flow rate exceeds 8 ONt/min, the uniformity deteriorates, and the occurrence of fuzz and thread breakage rapidly increases, resulting in a decrease in operational stability. According to the inventors' observations, flow 1
When j1 exceeded 8ONt1 minute, the yarn swayed considerably, especially at the entrance and exit of the IJll tropical zone, and the running condition of the yarn became unstable.

Especially from the point of view of uniformity, the flowmeter is 10 to 5 ONt1.
min is preferable, and 10 to 3 ONt/min is even more preferable.

In addition to this, it is essential that the temperature of the heated gas be Tg+10°C or higher. Here, Tg is the glass transition temperature of the polymer.

If the temperature of the heated gas is less than Tg + 10°C, the effect of introducing the heated gas will not be fully exhibited, and the mechanical properties will also deteriorate.
Uniformity also deteriorates. Especially when the heating gas temperature is 100℃~30℃
At 0°C, yarns with good mechanical properties and uniformity can be stably obtained without yarn breakage.

In this way, by introducing heated gas at a flow rate and temperature within a specific range into the heating zone, a yarn with satisfactory mechanical properties and uniformity can be produced. ) +', , r+runo-go.

At this time, it is preferable to maintain the ambient temperature at a high temperature (1) to the heated hydrofluoric acid into which heated gas is introduced. That is, it is preferable to maintain the temperature of the inner wall surface of the heating zone at a high temperature of 1. In other words, it is preferable that the inner wall surface l function of the heating zone is equal to or higher than Tg. If the temperature of the wall surface of the heating/ji1 region is less than Tg, no matter how much heated gas is applied, the effect cannot be fully exhibited. Particularly suitable results are obtained when the temperature of the heating zone (i) is 150 to 275°C.

In the present invention, the yarn passed through the heating zone as described above (7 yarns are taken up at a taking-up speed of sooom/min or more. The taking-up speed is not less than 3000 m/min) and is sufficiently satisfactory (mechanical Unable to obtain yarn of the same quality.Furthermore, the take-up speed is 3000
m/min/1 Ivl tends to deteriorate the uniformity, contrary to the effect of introducing heating gas into the heating zone as in the present invention.

That is, in the present invention, iI: is subtracted + ('i, If degree 30
00 m/min or less during the heating zone. ; is 10-8
ONt/min, the temperature is lTg-1-10]'CJ so1-
Only by introducing gas (1) can a yarn with satisfactory uniformity and mechanical properties be obtained without any operational problems.

Note that the heating zone in the present invention is a cylindrical l/i
Although it is possible to use a chicoop or the like having a rectangular cross section, the shape is not limited to the above-mentioned shape as it is sufficient to heat the space in which the yarn runs.

In addition, the method for raising the temperature of the atmosphere in the heating zone is generally to heat the area around the heating zone by electric heating or heating with a heating medium, but this is not limited to this. explain.

FIG. 1 is a longitudinal sectional view of a heating cylinder showing an example of a heating zone used in the present invention. In Fig. 1, 1 is an InI heat cylinder, 2
3 is a small hole, and 4 is an electric heater.

Does the cooled yarn Y run in the heating cylinder 1 with non-contact elongation? −j and undergo heat treatment. Heating gas (j(supply i'il(
is provided, and heated gas is introduced into the heating cylinder 1c through the small hole 3.

Regarding the method of introducing the heated gas, Fig. 1 shows a method of introducing it through the small hole 3. However, the method is not limited to this. In addition, as the heated gas, in addition to air, nitrogen, nitrogen, Although inert scum such as helium or water vapor can be used, it is especially preferable to use air or inert scum bc because there are fewer operational problems. (7
, Below, it is preferable to be completely cooled at VC% temperature of 1. 1111 (It is preferable that the state of the yarn introduced into the ii region is not completely bundled. This is because, as mentioned above, if the yarn is introduced into the heating zone in a bundled state, the temperature of the yarn will rise. Therefore, the heating zone must be kept at a very high temperature, which is disadvantageous in terms of cost.

<Effects of the invention 5. :) As mentioned above, drawn yarn with excellent mechanical properties and good uniformity can be spun for the first time by introducing heated gas at an appropriate temperature and flow rate into the heating zone and taking it off at a take-up speed of 3 ooom/min or more. It can be manufactured in just one step.

Note that the polyester fiber obtained according to the present invention has properties almost equivalent to those of conventional drawn yarn.

It has an excellent property that it can be used in all fields where drawn yarn is conventionally applied.

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

In addition, the physical properties in Examples were measured as follows.

A6 strength elongation Measured using a Tenno/Ron tensile tester manufactured by Toyo Baldwin Co., Ltd. under conditions of a sample length of 200 threads and a tensile speed of 100 min/min to obtain an elongation of 1 degree.

B. Uniformity (Worcester's mottling) Yarn speed 25
m/min, range ±12.5%, and chart speed 5 am/min, the thickness unevenness in the fiber axis direction was determined to be 1lllll, and the U% value was determined.

C1 Glass transition temperature Tg The glass transition temperature Tg is 10 m of polymer once melted using a differential calorimeter DSC-IB model manufactured by Lumar Co.
The measurement was made from the curve of the change in heat amount obtained by rapidly cooling the sample g and heating it at a temperature increase rate of 16° C./min in an atmosphere of +N2 gas.

Example-1 Polyethylene terephthalate with a glass transition temperature of 72°C was melted at 290°C, and a 1" gold (diameter 0.
2 vIIφ). Discharge wit 33,3 per minute
It was set as g. 25 m/min, 25
After cooling the yarn to room temperature by applying cooling air at ℃ over a length of 1 m, it was placed in a heating cylinder with a length of 1 m and an inner diameter of 15 mm as shown in Fig. 1 installed 2 m below the mouthpiece. Introduced yarn. The temperature of the cylinder wall of the heating cylinder was set at 200°C. Four small holes with a hole diameter of 4 mm were provided in the wall of the heating cylinder on the side closer to the mouthpiece, and heated air was introduced through the small holes. The set temperature of the heated air was 200° C., and the flow rate of the heated air was changed as shown in Table 1, and the yarn was taken at a take-up speed of 4 ooom/min to obtain a yarn of 75 denier-36 filament.

Table 1 shows the strength and elongation of the yarn taken and the U% value.

<Table-1> As apparent from Table-1, the present invention σ) q-center ll-11
Satisfy Ri flow rate 1O-8ONA/min/r6!1~
? In this case, a yarn with good strength and elongation can be obtained, and the force and tension UφIt
! j<, 1l ((Good. Especially the sight is 10-3ON
/:/e's 163-5, the uniformity is also very M] and the eldest daughter f
+), almost no fuzz is generated; i').

However, when the flow rate is 1ONl/min vc/iyHdada/fg 1.2, the mechanical properties also deteriorate.
l (f also becomes significantly larger.Especially when heated air is introduced 1.
/'1 In i61.

Because the uniformity deteriorates extremely, the force of A＼Lllll 1
How big is the effect of introducing 1M air?

In addition, when the heated air flow rate exceeds BONt1 minute, 1610~1
In case of 2, the uniformity deteriorates and the number of λ[1 per hair θ increases dramatically.

Example-2 The flow rate of heated air introduced into the heating cylinder was kept constant at 2ONt/min, and the temperature was as shown in Table-2 (modified). A yarn of Neal-36 filament was obtained. The strength and elongation of the obtained 1+, Puko yarn, and U% value are shown in Table 2.

<Table 2> As is clear from Table 2, 7615 to 21, which satisfy the heating air temperature range T≧'rg+1o of the present invention, can satisfy the mechanical properties of 1 and provide yarn with good uniformity. It was done. In particular, +1616 to 19 has a low U% value.

It can be seen that the uniformity is extremely good.

However, it is outside the scope of the present invention /f613°14
The U% value is also large, resulting in low strength and high elongation.

I know it's not good.

Example-3 Same as Example 1+11-1, except that the temperature of the air introduced into the heating cylinder was 200°C, the flow rate (+1° was 0 and 2ONt 1 minute, and the take-up speed and 111 output were changed as shown in Table 3). A yarn of 75 denier and 36 fissure of 71 mm was obtained under the following conditions.The strength and elongation and U% values of the obtained yarn are shown in Table 6.

<Table-5> As is clear from Table-3, in the example where the take-up speed is lower than 3000 m7 min/f622~25,
It can be seen that even after passing through the heating cylinder, the strength and elongation properties that can be used for practical use have not yet been achieved. Also, even if the heated air is O, 2ONt1
There is no significant difference in strength and elongation even when heated, and the uniformity deteriorates when heated air is introduced.

However, when the take-up speed is 3000 m/min or more, the mechanical properties are poor and the uniformity is poor, but only after introducing heated air.
The mechanical properties have also reached a satisfactory level, and the uniformity is U%.
It can be seen that the value decreases significantly and becomes better.

Only by introducing heated air at a take-up speed of 3000 m/min or more in this way can yarns with satisfactory mechanical properties and uniformity be stably obtained without fuzz.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a heating cylinder showing an example of a heating zone used in the present invention. 1: Heating tube 2: Heating gas supply section 3: Small hole 4: Electric heater Y: Thread r included) Fig. 1 ox'Jl, ? -Sell 1 pile+-IX-:':”:2・(So,
1fri1'1lLl I (Monday 11 Director General of the Patent Office Mr. Wakasugi Yorinto1, Table of the Case KoShowa 5841 4?j'Jl'I Petition No. 1812482, Name of Invention Polynis 1 Lulu Prefecture ([Production of 3hIj Method 4, correction order day i] Spontaneous 5, supplement i, E K J: ri increase 1jll'l light n5)
106, subject of correction 7, content of correction 1) Specification iM 112, page 2, line 11 1' b m, /min J to r 50m7 minutes'' correction. (2) Specification Furukawa Page 13 (Table 1) In the column of No, ica and No, 2 judgment], change Jri(puru [1j1 Deterioration of mechanical properties] to "(Mechanical f!t ¥! (3) Specification Furukawa, page 14, line 8 [1] ``The mechanical properties also deteriorate, and J is revised to ``(mechanical bamboo f'+ '
It is corrected as follows. (4) Line 3 from the bottom of No. 15 of the specification () Correct “largely low intensity” to “largely, relatively low intensity”.

Claims (1)

[Scope of Claims] A thermoplastic polyester polymer is melt-spun from a spinneret, once cooled to below the glass transition temperature, and then heated again. When heating and stretching the strip. A method for producing polyester fibers, which comprises actively introducing a heated gas that satisfies the following conditions into a heating zone, and taking off at a take-off speed of goooom/min or more. Temperature of heated gas T (Q T≧Tg+10 heated gas flow F (N11 minutes (normal liter 7 minutes)) 10≦F
≦80 (Tg is the glass transition temperature of the polymer)