JPH08246235A - Production of polyester fiber - Google Patents

Abstract

PURPOSE: To efficiently and safely produce polyester fibers with high productivity, suitable for the purposes of resin-coated cloths, heavy cloths, belts, sewing threads, high in strength and elongation and excellent in heat stability. CONSTITUTION: A polymer mainly comprising a polyethylene terephthalate of 1.0 or higher intrinsic viscosity is melt-spun, the undrawn yarn is passed through a heated cylinder, then taken up with the first roller, subsequently drawn, and subjected to a relaxation treatment between a final draw roller and a relax roller while interlacing the yarn to give a drawn polyester yarn. In these operations, the peripheral speed of the first roller (V) is set to 550-1,100m/min, the relaxation rate (R%) between the final draw roller and the relaxation roller is set to -0.009V+15<=R<=-0.012V+22, and the temperature of the final draw roller (T deg.C) is set to 0.05V+185<=T<=0.05V+205. This process can realize industrially advantageous production.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention has a high strength, a high elongation, and a low heat shrinkage ratio, and is used for resin-coated fabrics,
The present invention relates to an improvement in a method for producing polyester fibers suitable for heavy cloth applications, rubber reinforcement applications such as belt materials, and sewing thread applications.

[0002]

2. Description of the Related Art Polyester fibers containing polyethylene terephthalate as a main component have various excellent properties and are widely used not only for clothing but also for industrial applications.

When polyester fibers are used in industrial applications, the properties which are generally regarded as the most important are their mechanical properties, that is, their strength and elongation. Depending on the specific application, this polyester fiber may be heated when it is processed into a product or used after being processed into a product. In such a case, the dimensions of the polyester fiber are thermally stable in order to enhance the process passability and ensure the stability of the product,
That is, it is further required that the shrinkage rate during heating (dry heat shrinkage rate) is small.

Therefore, as a method for obtaining such a polyester fiber having a low dry heat shrinkage ratio, JP-A-61-1326 is used.
No. 16, 1500 m / min
A method for drawing the above-mentioned undrawn yarn which has been taken at a high speed is known. However, since the strength and elongation product of the fiber obtained by such a method is lowered, it is difficult to obtain a fiber suitable for an application in which a high dry elongation and a low dry heat shrinkage rate are required.

A method for producing a polyester fiber having such a high strength and a high elongation as well as a low dry heat shrinkage factor is described, for example, in Japanese Patent Publication No. 58-51524.
It is proposed in Japanese Patent Laid-Open No. 610 and Japanese Patent Laid-Open No. 210039/1990.

Japanese Patent Publication No. 58-51524 and Japanese Unexamined Patent Publication No.
The method described in Japanese Patent No. 251610 discloses a fiber having a small heat shrinkage ratio by strengthening heat application to the fiber at the time of orbiting the final drawing stage roller in the spinning direct drawing process and promoting the structural fixing of the fiber by heat. Is what you are trying to get. That is, stretched by a high temperature stretching roller,
Further, a polyester fiber having a low shrinkage ratio is to be obtained by bringing a yarn into contact with a heating roller at a higher temperature for a long time.

In the method described in Japanese Patent Laid-Open No. 210039/1990, a fiber having a small heat shrinkage ratio is provided by efficiently providing heat to the yarn by providing a heat fixing roller with an auxiliary heat source. Is what you are trying to get.

[0008]

However, the Japanese Patent Publication No. 58-
Since the method described in Japanese Patent No. 51524 discloses strengthening heat application in order to reduce shrinkage, it is necessary to take a long contact time between the yarn and the heating roller. It is necessary to either take a measure such as lowering it, increasing the number of turns to the heating roller, or using a heating roller with a large diameter. If these measures are taken, the production speed will be reduced, a long roller will be required, and it will be difficult to produce multiple yarns with one drawing system. However, there is a problem that it is difficult to stably manufacture it due to its nature.

Further, in the method disclosed in Japanese Patent Laid-Open No. 2-251610, since a high-temperature hot plate is provided in the vicinity of the yarn, the yarn is likely to melt and adhere to the hot plate at the time of yarn breakage, resulting in high productivity. There is a problem that it is difficult to manufacture stably.
Further, although the polyester fiber obtained by such a method has a low dry heat shrinkage, there is a problem that the toughness (strength / elongation product) tends to be small due to excessive heat setting.

Furthermore, in the method disclosed in JP-A-2-210039, the production rate of polyester fiber is 2000-
Since the speed was 2500 m / min, the productivity was low.

As described above, a polyester fiber having excellent mechanical properties such as high strength and high elongation and a low dry heat shrinkage ratio, which is suitable for applications such as resin-coated cloth, heavy cloth, belt material, and sewing thread, is manufactured. All of the conventional manufacturing methods for achieving the above are inadequate in that they are stably manufactured with high productivity.

Therefore, the present invention solves the above-mentioned problems of the prior art and has excellent mechanical properties such as high strength and high elongation and a low dry heat shrinkage rate with stable and high productivity. A main object of the present invention is to provide a method for producing a polyester fiber, which is advantageous in industrial production.

[0013]

To achieve this object, the present invention melt-spins a polymer containing polyethylene terephthalate having an intrinsic viscosity of 1.0 or more as a main component, and heats the spun yarn into a heating cylinder. In the method for producing a polyester fiber, a drawn yarn is obtained by a method of performing a relaxation treatment while performing a relaxation treatment while performing a entanglement treatment between the final stretching roller and the relaxation roller, followed by stretching with a first roller and subsequently stretching. The peripheral speed (V) of the first roller is 550 to 1100.
m / min, the peripheral speed of the first roller (Vm / min)
And the relaxation rate (R%) between the final stretching roller and the relaxation roller satisfy the relationship of −0.009 · V + 15 ≦ R ≦ −0.012 · V + 22, and the temperature of the final stretching roller (T
C.) and the peripheral speed (Vm / min) of the first roller satisfy the relationship of 0.05 · V + 185 ≦ T ≦ 0.05 · V + 205.

That is, the method of the present invention is first applied by combining a specific spinning speed, a specific relaxation rate according to the spinning speed, and a final drawing roller temperature.
It was made by finding that a polyester fiber having both excellent mechanical properties and heat shrinkage properties can be obtained stably and efficiently.

The method for producing polyester fiber of the present invention will be described below.

The polymer used in the method of the present invention is a polyester containing polyethylene terephthalate as a main component, and as a part thereof, isophthalic acid, adipic acid, sebacic acid, dimer acid, 2,6- Naphthalenedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, etc., and a small amount of diol components such as diethylene glycol, neopentyl glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, polyalkylene glycol, etc. Further, pentaerythritol, trimethylolpropane, trimellitic acid, trinosinic acid, etc. may be used to impart a small amount of branching.

The polymer may contain an inorganic substance such as titanium oxide, silicon oxide or calcium carbonate, and may further contain a weathering agent, an antioxidant or the like.

The intrinsic viscosity of the polymer used in the present invention is 1.
It is indispensable to be 0 or more, and preferably 1.1 or more. When the intrinsic viscosity of the polymer used is less than 1.0, it is difficult to sufficiently increase the strength-elongation product of the obtained polyester fiber.

The intrinsic viscosity of the polymer in the method of the present invention is a value obtained by measuring the relative viscosity ηr of a solution in which 8 g of a sample is dissolved in 100 ml of orthochlorophenol using an Ostwald viscometer and using the following approximate expression. is there. Intrinsic viscosity = 0.0242 · ηr + 0.2634

In the method of the present invention, the spun yarn melt-extruded from the melt-spinning machine passes through the heating cylinder, is cooled by the cooling device, is oiled, and is continuously circulated by the first roller. Be taken over.

The heating cylinder used here has a cross-sectional area larger than the distribution range of the discharge holes on the surface of the die, and is usually a tubular body made of a heater having a circular inner cross section, and is below the die block. Directly or via suitable insulation. The length of the heating cylinder used is preferably 30-100 cm, and the temperature of the inner wall surface of the heating cylinder is 200-
It is preferably 350 ° C. A cooling device for blowing cooling air is connected to the lower part of the heating cylinder, but the heating cylinder and the cooling device do not necessarily have to be directly connected,
An appropriate length of heat insulating material may be interposed therebetween.

After passing through the cooling device, the thread is applied with an oil agent. When applying the oil agent, the thread must be completely solidified. For that purpose, the place where the oil agent is applied is the spinneret surface. Is preferably 3 m or more.

The yarn to which the oil agent is applied is wound around the first roller and taken up, and is continuously drawn by the multistage rollers without being once wound. The number of drawing stages is preferably 2 or more in order to stably obtain fibers having high strength.
Three-stage stretching including pre-stretching, main stretching and post-stretching is preferable.

The stretching ratio in the three-stage stretching method is the first
The preliminary stretching between the roller and the second roller is 1.1 times or less, the main stretching between the second roller and the third roller is 50 to 80% of the total stretching ratio, the third roller and the fourth roller. The post-stretching with the (final stretching roller) is preferably 20 to 50% of the total stretching ratio. When the draw ratio and the draw ratio are out of the above ranges, the yarn diameter unevenness and fluff tend to increase, which is not preferable.

In the present invention, the peripheral speed of the first roller is important, and its range is 550 m / min or more and 1100 m / min.
It is essential that it be less than or equal to min, preferably 600 m
/ Min or more and 1000 m / min or less. When the peripheral speed of the first roller is less than 550 m / min, high productivity cannot be obtained. On the contrary, when it exceeds 1100 m / min, it is not possible to stably obtain a fiber having both high elongation and low dry heat shrinkage.

In order to improve the stability of yarn production, it is necessary that the yarn thus stretched between the multiple stages of rollers is subsequently subjected to relaxation treatment while being entangled between the final stretching roller and the relaxation roller. is there. The pneumatic pressure of the fluid for this confounding treatment is preferably 1.5 to 6 kg / cm ² .

The relaxation rate R (%) between the final stretching roller and the relaxation roller is a value expressed by R = (final stretching roller speed-relaxation roller speed) × 100, and this relaxation rate is In the method of the present invention, it is essential that the specific value is set according to the peripheral speed (Vm / min) of the first roller. The value must be within the range represented by the following formula: -0.009 · V + 15 ≦ R ≦ −0.012 · V + 22, and preferably −0.009 · V + 15.5 ≦ R ≦ −0. 012 V +
It is within the range of 21.7, and more preferably −0.009 · V + 16 ≦ R ≦ −0.012 · V + 2.
It is within the range of 1.5.

This relaxation rate (R) is [-0.009.V +
15], it is difficult to combine high elongation and low dry heat shrinkage, and conversely, [-0.012
・ If it is larger than V + 22], stable yarn production is difficult.

To achieve the object of the present invention,
The temperature (T ° C.) of the final stretching roller needs to be a specific value according to the peripheral speed (Vm / min) of the first roller. Specifically, a range represented by the following formula: 0.05 · V + 185 ≦ T ≦ 0.05 · V + 205 is necessary, and preferably 0.05 · V + 187 ≦ T ≦ 0.05 · V + 203. It is within.

The temperature (T ° C.) of the final stretching roller is
When it is smaller than [0.05 · V + 185],
Even when it is larger than [0.05 · V + 205], the strength-elongation product of the obtained fiber becomes small, and only the fiber having insufficient strength or elongation can be obtained. Furthermore, the temperature (T ° C) of the final stretching roller is [0.05 · V + 205].
If it is larger than the above range, fusion of the yarn to the final drawing roller is likely to occur when yarn breakage occurs, it takes time and effort to remove the fused yarn from the roller, and the operability is deteriorated.

According to the above-mentioned method of the present invention, it becomes possible to stably and highly productively produce polyester fibers having high strength, high elongation and low dry heat shrinkage. The polyester fiber obtained by the method of the present invention has a strength of 8 g / d or more, an elongation of 20% or more, and a temperature of 150 ° C.
It is possible to have excellent characteristics such that the dry heat shrinkage ratio is 3.8% or less.

The strength and elongation of the fiber in the present invention are
It is a value measured by the method described in JIS-L-1017. The dry heat shrinkage ratio (%) at 150 ° C is 150
It is a value obtained by heat-treating at 0 ° C. for 30 minutes under no load, measuring the yarn length before and after that under a load of 0.05 g / d, and dividing the difference in yarn length before and after heat treatment by the yarn length before heat treatment. .

It is preferable that the strength is 8 g / d or more, when the fiber obtained is used to manufacture a fiber product, the necessary strength can be easily imparted to the product. Further, the elongation of 20% or more is suitable for suppressing breakage during processing or use. Furthermore, the dry heat shrinkage at 150 ° C. is 3.8% or less,
In particular, the content of 3.6% or less is suitable for improving process passability in a process involving heating such as heat setting after weaving and suppressing the occurrence of puckering when used as a sewing thread.

Further, in the polyester fiber, the difference between the dry heat shrinkage at 200 ° C. and the dry heat shrinkage at 150 ° C. is 3.8% or less, which makes the process passability good,
It is suitable for suppressing fabric strain after heat treatment.

[0035]

EXAMPLE A polyethylene terephthalate chip having an intrinsic viscosity of 1.21 was supplied to a usual melt spinning apparatus, and the pore size was 0.
6 mm, 300 from spinneret with 48 discharge holes
Melt extruded at ℃, after passing through a heating cylinder of 50 cm in length heated to 340 ℃, wind speed 40m / by the cooling device
After cooling by blowing min cooling air over a length of 120 cm, the oiling agent was applied by an oiling roller, the oil was applied to the first roller, and the oil was wound around the first roller, and subsequently stretched without being once wound to perform relaxation / entanglement treatment.

The drawing was carried out in three steps, and the first step was a preliminary drawing with a draw ratio of 1.03 times. A compressed air nozzle was used for the confounding treatment during relaxation, and the compressed air pressure was 3 kg / cm ² . The other conditions were as shown in Table 1.

For comparison, the yarn was produced in the same manner as in the above example except that the intrinsic viscosity of the polyester, the temperature of the final stretching roller, the relaxation rate in the relaxation treatment, and the pneumatic pressure in the entanglement treatment were changed as shown in Table 1.

Properties of the polyester fiber obtained, and
The spinning conditions were evaluated and the results are shown in Table 1. On this occasion,
The spinning condition was judged according to the following criteria, depending on the number of occurrences of yarn breakage between the first roller and the relaxation roller and the presence or absence of fusion of the fiber to the final drawing roller at the time of yarn breakage. [Status of occurrence of yarn breakage] ○: Almost no yarn breakage occurred,
Δ: Slightly generated, ×: Largely generated [Fiber fusion state] ◯: No fiber fusion, ×:
With fusion

As is clear from the results shown in Table 1, even if the first roller speed is as high as 550 m / min or more, if the conditions within the range specified in the present invention are satisfied, the occurrence of yarn breakage is small and the yarn is A polyester yarn having high strength, high elongation and low shrinkage could be stably obtained without fusion to the stretching roller at the time of breaking.

On the other hand, when the temperature of the final drawing roller was outside the scope of the present invention in Comparative Examples 1, 3 and 4, yarn breakage and fusion to the roller occurred considerably, and stable yarn making was difficult.
Further, in the case of Comparative Example 2 in which the relaxation rate was too low, the desired high elongation level and low contraction level could not be obtained. In the case of Comparative Example 5 in which the intrinsic viscosity of the polyester was too low, a desired strength level could not be obtained, and moreover, there were many yarn breakages and stable yarn production was difficult. Furthermore, in the case of Comparative Example 6 in which the entanglement treatment was not performed, it was difficult to stably produce a yarn with many yarn breakages.

[0041]

[Table 1]

[0042]

EFFECTS OF THE INVENTION According to the method of the present invention, polyester fibers having high strength and high elongation and excellent thermal stability, which are suitable for resin coated cloth, heavy cloth, belt material, sewing thread, etc. In addition, it can be efficiently manufactured with high productivity, and industrially advantageous production becomes possible.

Claims (7)

[Claims] 1. A polymer mainly composed of polyethylene terephthalate having an intrinsic viscosity of 1.0 or more is melt-spun, the spun yarn is passed through a heating cylinder, and then taken up by a first roller, followed by continuous spinning. In the method for producing a polyester fiber, in which a stretched yarn is obtained by stretching and performing a relaxation treatment while performing an entanglement treatment between a final stretching roller and a relaxation roller, a peripheral velocity (V) of the first roller is 550 to 110.
0 m / min, the peripheral speed of the first roller (Vm / min
) And the relaxation rate (R%) between the final stretching roller and the relaxation roller satisfy the relationship of −0.009 · V + 15 ≦ R ≦ −0.012 · V + 22, and the temperature of the final stretching roller ( T
C.) and the peripheral speed (Vm / min) of the first roller satisfy the relationship of 0.05 · V + 185 ≦ T ≦ 0.05 · V + 205. 2. The method for producing a polyester fiber according to claim 1, wherein the stretching is performed in three steps of pre-stretching, main stretching and post-stretching. 3. The stretching ratio of the preliminary stretching is 1.1 times or less, the stretching ratio of the main stretching is 50 to 80% of the total stretching ratio, and the stretching ratio of the post-stretching is 20 to 20% of the total stretching ratio. 5
It is 0%, The manufacturing method of the polyester fiber of Claim 2 characterized by the above-mentioned. 4. The method for producing a polyester fiber according to claim 1, wherein the length of the heating cylinder is 30 to 100 cm and the temperature of the inner wall surface is 200 to 350 ° C. 5. The method for producing a polyester fiber according to claim 1, wherein an entanglement treatment under a pressure and air pressure of 1.5 to 6 kg / cm ² is performed between the final stretching roller and the relaxation roller. 6. The strength of the obtained polyester fiber is 8.
g / d or more, elongation of 20% or more, dry heat shrinkage at 150 ° C. of 3.8% or less, and difference between dry heat shrinkage at 200 ° C. and dry heat shrinkage at 150 ° C. is 3.8. % Or less, The method for producing polyester fiber according to claim 1, wherein 7. The method for producing a polyester fiber according to claim 1, wherein the obtained polyester fiber is a polyester fiber for resin-coated cloth, heavy cloth, rubber reinforcement, or sewing thread.