JPS6147817A - Production of polyester yarn - Google Patents

Abstract

PURPOSE:To obtain the titled yarn suitable of industrial uses, etc., having high strengh and elongation, dimensional stability, and fatigue resistance, etc., by spinning and drawing a polymer consisting essentially of ethylene terephthalate unit at high speed under controlled temperature condition while setting a heating column and an insulating column just under a spinneret. CONSTITUTION:In spinning and drawing directly a polyester having >=90mol% repeating structure unit of ethylene terephthalate at >=1,500m/min spinning speed, the heating column 3 having 5-30cm length is set just under the psinneret 2, the unheated insulating column 4 with 2-30cm length is fixed under the heating column 3, an atmosphere from the bottom face of the spinneret 2 to 7-60cm below is made as the gradually cooling zone 5, the atmosphere temperature of the gradually cooling zone 5 is regulated at 550-150 deg.C, a temperature gradient is reduced as the position is lowered, and the yarn Y is treated. The yarn is provided with a finishing oil by the oil rolls 8 and 9, drawn by the drawing rollers 11 and 12, and wound by the winder 14, to give the aimed yarn.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention uses a direct spinning and drawing method with a fastening speed to achieve high strength and elongation.
The present invention relates to a method for stably and efficiently producing polyester fibers that have excellent dimensional stability and fatigue resistance and are suitable for industrial use.

(Prior art) In recent years, polyester fibers have been widely used as reinforcing materials for radial tires for passenger cars, especially as tire suits for carcass. Performance is required.

Examples of methods for manufacturing polyester TV fibers that satisfy the above tire performance include JP-A-53-58052 and JP-A-57-154410. JP-A-57-154411, JP-A-57-16+! ? , JP-A-58-1571B, JP-A-58-25914, JP-A-58-46117 and JP-A-58-98419, among others, polyethylene tele7ta V- After being melt-spun and slowly cooled by passing through a heating cylinder just below the spinneret,
Cool it, take it off at 1500~S OOOm for 7 minutes, and do not wind it once (stretching method (Japanese Patent Application Laid-Open No. 58-50511)
No. 2) is said to be highly effective in improving the desired dimensional stability and durability.

(Problems to be Solved by the Present Invention) However, in the method described in JP-A-58-303112, since the ambient temperature and spinning tension rapidly decrease in the cooling zone following the heating cylinder, This method has the disadvantage that yarn sway increases and single yarn breakage occurs frequently.

Moreover, each time the total denier or single yarn denier of the yarn is changed, it is necessary to adjust or change the length of the heating cylinder, so it is not necessarily an efficient method for repairing the device.

Therefore, the present inventors aimed to solve the above problems and to stably and efficiently produce polyester A/fiber with excellent dimensional stability and fatigue resistance without causing yarn sway or yarn breakage. As a result of extensive research, we found that by providing a heat-retaining cylinder at the bottom of the heating cylinder in the above method and creating a specific temperature gradient in the slow cooling zone, the above purpose can be effectively achieved, and the obtained a-fiber can be improved. It was discovered that strength and elongation were further improved, and the present invention was achieved.

(Means for solving the problem) That is, the present invention has a structure in which the repeating structural unit is 90 mo/l/9
When directly spinning and drawing polyester containing 6 or more terephthalate units at a spinning speed of +500 m7 minutes or more, a heating cylinder with a length of 5 to 50 cx is placed directly below the spinneret, and a heating cylinder with a length of 5 to 50 cx is placed at the bottom of the heating cylinder. An unheated heat insulating cylinder with a length of 2 to 30 mm is provided to create a slow cooling zone with an atmosphere of 7 to 60 α from the bottom surface of the spinneret, and the ambient temperature of the slow cooling zone is set to 35
The present invention provides a method for producing polyester fibers, which is characterized in that the temperature gradient is controlled to be from 0 to 150[deg.] C., and the lower the temperature, the lower the temperature.

Polyester, which is the material polymer of the present invention, is polyethylene terephthalate or ethylene terephthalate or ethylene terephthalate with 90 units.
It is a polyester copolymer containing mol/L-% or more, and may also be a mixed polymer containing 95 mol% or more of polyethylene terephthalate. This polymer has engineering V as CL.
? A high viscosity polymer having a Q of 0 or more, usually 95 to 1.40 is preferred.

The method of the present invention will be specifically described below with reference to the drawings.

Note that FIG. 1 is a process diagram to which one embodiment of the method of the present invention is applied, and FIG. 2 is an enlarged longitudinal sectional view of the spinning/cooling section used in the present invention.

First, the polymer is melted in a spinning head (not shown) and extruded through a spinneret 2 held by a spin block 1, that is, melt-spun into a spun yarn. The melt spinning temperature is preferably 290 to 310°C.

5 to 30α, preferably 5 to 15, directly below the spinneret 2
A heating tube 3 having a length of α is provided, and is heated by a heater (not shown) so that the atmospheric temperature inside the tube is 350 to 250° C. and becomes lower toward the bottom.

Note that the bottom surface of the spinneret 2 is inside the spin block 1.
In some cases, the length of the heating cylinder is 5 to 50 mm. cm simply means the distance from the bottom surface of the cap to the bottom end of the heating cylinder. Therefore, when the bottom surface of the base is located inside the spin block, the length of the heating cylinder itself can naturally be 5c11 or less.

Immediately below the heating cylinder 3, an unheated heat insulating cylinder 4 having a length of 2 to 50 cm, preferably 5 to 20 cIl is attached in close contact.

And the length consisting of the heating cylinder 3 and the heat insulation cylinder 4 is 7 to 60α
This range is the bottom of the groove as the slow cooling sea 75.

If the length of the heating @S is less than 5α, it is difficult to obtain a high-strength yarn (and if it exceeds 30α, a fiber with excellent dimensional stability cannot be obtained, which is not preferable. Also, if the length of the heating cylinder 4 is less than 2
If it is less than 1, yarn wobbling and yarn breakage can be effectively prevented.
If it exceeds 1, Worcestershire spots will occur in the yarn and the dimensional stability of the resulting fibers will decrease, which is not preferable.

The ambient temperature inside the heating cylinder 3 is 350 to 250°C,
And preferably, the lower the temperature, the lower the temperature, the lower the temperature, the lower the temperature.
do. The heat retaining cylinder 4 is not heated in principle, but is maintained at a temperature higher than isQ°C by the atmospheric temperature of the heating cylinder accompanying the yarn. Therefore, a temperature gradient is formed in the slow cooling sea 75 so that the temperature gradually decreases upward and downward, thereby further promoting the slow cooling effect.

If necessary, a cooling cylinder 6 is installed at the bottom of the heat insulation cylinder via a heat insulating plate.
is provided. As the type of cooling cylinder 6, a cold air blowing type annular chimney is suitable, and its length is 10 to 6 mm.
0α, and (20 to 40) are appropriate.

By minimizing the gaps between the heating cylinder and the heat-insulating cylinder, and between the heat-insulating cylinder and the cooling cylinder to form a closed system, the temperature of each part can be ideally maintained and uniform cooling can be achieved.

After passing through such an annealing zone 5 and a cooling cylinder 6, the yarn is cooled and solidified in a yarn path duct Z adjacent to the lower part of the cooling cylinder, and then oiled by an oil supply device 8 and taken off by a take-off roller 10.

The take-off speed at the take-off roller 10, that is, the spinning S degree, is usually +500 m7 minutes or more, particularly 2000 m7 minutes or more.

The yarn drawn in this way is drawn continuously without being 8T8. In order to make the polyester/I/fiber of the present invention high in strength, a multi-stage hot drawing method is adopted. A preferred stretching method is as follows.

The taken loaf 10 is heated to 100° C. or lower or not heated. The first stretching roller 11 is heated to 65 to 200°C, preferably 85 to 160°C, and is heated to 1.2 to 1.8 times 1.
Stage stretching is performed.

The second stretching row 12 is 160 to 260°C, preferably 1
The film is heated to 80 to 250°C, and a second stage stretching of 1.1% and 1.6 times is performed between it and the first stretching loaf II. Further, third and subsequent stages of stretching are performed as necessary, but the overall stretching ratio is 2.0 to 5. 5 times is preferred.

The drawn yarn is then subjected to tensile strength @, a-13 (no heating or 2
(heated to 40℃ or less) between the M final stretching roller (L? ~ 1
．． After being subjected to relaxation or tension treatment at 1x, usually α95 to 1.0x, it is rolled up in Wine Sea 14.

(Function) According to the method of the present invention, by further providing a heat insulating cylinder at the bottom of the heating cylinder and creating a temperature gradient in the slow cooling zone, yarn swaying and yarn breakage in the cooling cylinder are reduced and yarn spinning performance is improved. Moreover, since the slow cooling effect is promoted, the strength and elongation and dimensional stability of the obtained fibers are further improved.

In addition, when attempting to spin fibers with different total deniers using the same device, changing the length of the heating tube depending on the desired fiber performance requires extremely complicated work, but it is not necessary. In the present invention, the length of the heating cylinder is set in advance to a certain length, and the apparatus can be easily repaired by simply changing the length of the non-heating heat-insulating cylinder. To change the length of the heat insulating tube, you can either construct a retractable heat insulating tube, or prepare several types of heat insulating tubes with different lengths.
This can be achieved efficiently by replacing them.

(Example) The present invention will be further explained from Example e below. The tenacity, strength and elongation of the fibers in the Example are values measured according to the method of J Engineering 5-LIOI7, and the dry heat condition A¥ was evaluated based on the following criteria. Take the sample in the shape of M, and heat it at 20℃, 65%.
After leaving the R'H temperature-controlled room for 1024 hours, the sample (L1
Length lo measured by applying a load equivalent to 1 g/li
The sample was left in an oven at 150°C for 30 minutes without tension, and then left in the temperature-controlled room for 4 hours, and then the load was applied again and the measured length A'+ was calculated using the following formula. Calculated.

Dry heat yield rate z (l1o-1+)/lo X I 00
(96) A polyethylene terephthalate film having a polyethylene terephthalate density of 12 eq/l, V + , s s , and a carboxy μ end group density of 12 eq/l was spun using the Li1E welding and drawing process shown in FIG.

An extruder-type spinning machine was used, and the spinning temperature was 295°C. Spun q-gold has a hole diameter (L60 size φ, number of holes 5
A 6Q hole with spinning holes arranged in five annular rows was used, and the discharge rate was 914 g/min.

Directly below the cap, a heating tube with the length shown in Table 1 and a diameter of 340mm is attached, and directly below that, a heating cylinder with the length shown in Table 1 and a diameter of 340mm is attached in close contact for slow cooling. The zone was grooved.

The lower part of the heat insulation cylinder has a length of 201 mm and a diameter of 25 mm through a heat insulating plate.
A cooling cylinder of zero size was attached, and cold air at 25°C was blown from the outer periphery of the yarn at a speed of 35 m/min to rapidly cool the yarn. The inside of the heating cylinder is the first
Table 1 also shows the results of heating to the temperature shown in the table and measuring the temperature at the bottom of the unheated heat retaining cylinder. The rapidly cooled spun yarn then passed through a yarn guide duct, was applied with an oil agent by an oil supply device, and was heated to 70°C. It was picked up by Neson Roller (PR) at a speed of 2500 m/min.

Next, the yarn is once wound up and subjected to a first drawing between a second drawing loaf (IDR) heated to 85°C, and then a second drawing loaf (IDR) heated to 250°C.
2DR), a second stage of stretching was performed. IDR and 2D
The stretching ratio between R is fixed at 1,275 times, and FR and ID1
By changing the stretching ratio between
The plants were cultivated as shown in the table. After 196 degrees of relaxation was applied between the 2DR and an unheated relaxation roller, the film was wound up.

Table 1 also shows the spinning and drawing conditions, spinning properties, and drawn yarn characteristics.

As is clear from the results in Table 1, the method of the present invention (&1
, 6.7) Accordingly, a polyester m5 miscellaneous material having excellent properties can be obtained with stable yarn-spinning properties without yarn breakage. On the other hand, when the heat retaining tube is not provided (f2) and when the heating tube is short (&3), yarn breakage is significant and the strength and elongation characteristics of the fibers are also poor. Furthermore, even if both a heating cylinder and a heat-insulating cylinder are provided, if the length thereof is outside the specified range of the present invention (&4
．． 5) cannot obtain the desired improvement effect.

(Effects of the Invention) According to the method of the present invention, in the high-speed direct spinning drawing method, it is possible to achieve high strength and elongation (and excellent dimensional stability) with good spinning properties with less yarn wobbling and yarn breakage. Polyester fibers can be produced stably and efficiently, and the resulting polyester fibers have excellent properties and are suitable for industrial applications such as tire cords.

[Brief explanation of the drawing]

FIG. 1 is a process diagram to which an embodiment of the method of the present invention is applied, and FIG. 2 is an enlarged longitudinal sectional view of the spinning and cooling section used in the present invention. 1 - Spin block 2 - Spinneret 3 - Heating tube 4 - Heat retention tube 5 - Slow cooling zone 6 - Cooling tube 7 - Duct 8 - Oil application roll 9 - 1 10 - Take-up loaf 11 - First drawing loaf 12 - Second Stretching loaf 13 ~ Tension adjustment roller 14 ~ Winder x ~ Yarn patent applicant Toshi Co., Ltd. Figure 1 Figure 2

Claims (1)

[Claims] When polyester in which 90 mol% or more of the repeating structural units are ethylene terephthalate units is directly spun and drawn at a spinning speed of 15,000 m/min or more, a heating cylinder with a length of 5 to 30 cm is placed directly below the spinneret, and a heating cylinder of 5 to 30 cm in length is placed directly below the spinneret. An unheated heat insulating tube with a length of 2 to 30 cm is provided at the bottom, and the atmosphere 7 to 60 cm from the bottom surface of the spinneret is set as a slow cooling zone. A method for producing polyester fiber, characterized by controlling the temperature gradient to a low temperature.