JPS63227813A - High-elastic modulus and high-strength polyester fiber and production thereof - Google Patents

Abstract

PURPOSE:To obtain the titled fiber suitable as tire cord materials, etc., by adding a polyester.polyether.block copolymer in a specific proportion to an ethylene terephthalate based polyester, melt spinning the resultant blend and drawing the obtained yarn under specific condition. CONSTITUTION:0.2-15wt.% polyester.polyester.block copolymer is added and blended with an ethylene terephthalate based polyester having >=0.7 intrinsic viscosity (IV) and the resultant blend is then melt spun at a temperature above the melting point of the polymer (A) and taken off so as to provide >=0.020 birefringence ratio of the resultant yarn after cooling and solidifying. The obtained yarn is subsequently drawn at >=90 deg.C temperature and a draw ratio expressed by the formula [NE is then natural draw ratio (%) of the undrawn yarn] and then drawn at 150-250 deg.C to afford the aimed fiber having >=150(g/d) initial tensile elastic modulus and >=8(g/d) tensile strength.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an ethylene terephthalate polyester fiber that has an unprecedentedly high modulus of elasticity and high strength properties, and a method for producing the same.

More specifically, based on melt-spinning, we are able to provide high-strength polyester fibers with high elastic modulus that have never been seen before at a practical price. The present invention relates to polyester a fibers that can be used as an alternative to steel as belt materials for radial tires, or as reinforcing materials for thermoplastic composites, and methods for producing the same.

(Prior Art) Ethylene terephthalate-based polyester fibers are usually obtained industrially by melt-spinning polyethylene terephthalate having a 1v of less than 1.2 at a temperature equal to or higher than its melting point, followed by hot drawing and heat treatment.

The physical properties of ethylene terephthalate polyester fibers obtained by such conventional methods are as follows: even in the case of high-strength fibers, the initial tensile modulus is 90 to 180 g/d1 strength 6.3 to 9 g
/d. (Industrial Textile Material Handbook: Japan Textile Machinery Society, 1978) (Problem to be solved by the invention) Ethylene terephthalate polyester fibers used for industrial materials such as tire cords and ropes have high elasticity. There is a demand for improved performance such as high strength, high strength, high fatigue resistance, and high wear resistance.

As part of our research into high performance ethylene terephthalate polyester fibers, we have developed a winding speed of 6,000 using the melt spinning method.
Shimizu et al. (Journal of the Japan Institute of Textile Technology vol. 1.33, , Hiro 5, T-208 (1977)
, vol, 34. , Na2, P-43 (1978))
Although it is well known that the tensile modulus is as low as 80 g/d.

Therefore, as an important method for achieving higher performance, it is expected to develop a manufacturing technology that uses high molecular weight ethylene terephthalate polyester and stretches it to a high degree. The conventional polymerization method for polyethylene terephthalate was s polymerization, which made it extremely difficult to increase its molecular weight, and the maximum molecular weight was 11flV = 1.8, but with advances in bacterial polymerization technology, IV It has become possible to obtain ultra-high molecular weight polyethylene terephthalate with a molecular weight exceeding 3.0, and the possibility of improving the performance of polyethylene terephthalate fibers has increased.

However, when trying to improve the performance of ultra-high molecular weight polyethylene terephthalate by melt spinning, the melt viscosity becomes extremely high (or
The fluidity of the melt is also extremely low, making spinning using conventional melt spinning methods extremely difficult. For this purpose, as seen in Japanese Patent Publication No. 19887-1987, Japanese Patent Publication No. 33727-1987, and US Pat. However, it has not yet been possible to obtain high-performance ethylene terephthalate polyester fibers.

On the other hand, ordinary polyethylene terephthalate) (IV Ta Seizo et al. (Fiber Science Society Journal vol. 1.35.1 m8, T-328 (1
There are also reports of 979)).

The results showed that the melting point of solid-phase polymerized drawn fibers was 276°C.
High melting point polyethylene terephthalate fibers have been obtained, but the initial tensile modulus of the fibers ranges from 50 g/d to 2.
It has decreased significantly to 0 g/d. Therefore, although this method can increase the melting point of the fiber, it cannot simultaneously increase the modulus of elasticity.

Generally, the performance required of TA fibers for industrial materials, such as fibers for tire cords reinforcing rubber, is desirably high strength and high elastic modulus. However, the tensile modulus of the current polyethylene terephthalate fiber for tire cords is 1.
Polyethylene terephthalate fibers with a tensile modulus of 30 to 150 g/d and 130 g/d are generally not used because the reinforcing effect of rubber is small.

Under such current circumstances, the present inventors have conducted intensive research on improving the performance of ethylene terephthalate polyester fibers, and have achieved a high elastic modulus of ethylene terephthalate polyester fibers, which could not be achieved with the conventional technology. The present invention aims to provide a high elastic modulus ethylene terephthalate polyester fiber that exhibits a novel 1am structure that is clearly distinguishable from conventional ethylene terephthalate polyester fibers, and a method for producing the same.

(Means for Solving the Problems) The present invention that has achieved the above objects has the following features: (1)
0 polyester/polyether/block copolymers
．． A high-modulus, high-strength polyester fiber comprising ethylene phrephthalate polyester containing 2 to 15% by weight and having the following properties (a) to (b).

(4) Initial tensile modulus (g/cl)≧150 (b)
Polyester e polyether φ
After blending the block copolymer polymer at a ratio of 0.2 to 15 percent, it is melted at a temperature above the melting point of the ethylene terephthalate polyester polymer, extruded from a nozzle orifice, cooled and solidified, and the birefringence of the drawn yarn is It is taken up so that the ratio is 0.020 or more, and it is drawn continuously after spinning or once wound up, and then stretched at a temperature of 90°C or less at a stretching ratio given by the following formula (c), and then further This is a method for producing a high-modulus, high-strength polyester fiber, which is characterized by stretching at a temperature range of 150 to 250°C.

(However, NE indicates the natural stretching ratio (%) of undrawn yarn.) In the present invention, a polyester-polyether block copolymer polymer is added to an ethylene terephthalate-based polyester polymer having an IV of 0.7 or more in the form of chips. The blend in a specific ratio is spun, and the polymer chains constituting the fiber of the present invention are stretched as highly as possible in the fiber axis direction, that is, the pre-stretching ratio of the fiber is as high as possible. This is achieved by making it larger.

More specifically, the method of the present invention and the properties of the obtained fibers will be explained in detail.

The ethylene terephthalate-based polyester used in the present invention is a polyester consisting of a dibasic acid mainly consisting of terephthalic acid and ethylene glycol, particularly polyethylene terephthalate. It is also possible to use a copolymerized product in an amount of mol % or less, preferably 5 mol % or less.

Here, main third components include inphthalic acid, sulfoisophthalic acid, adipic acid, neobentyl glycol, pentaerythritol, glycerin, polyethylene glycol, alkyl ether of polyethylene glycol, etc., but other known components are optional. Can be used for

The polyester-polyether block copolymer referred to in the present invention refers to a polyester unit containing 60 mol% or more, preferably 80 mol% or more of polytetramethylene terephthalate units as a hard segment, and poly(tetramethylene ether) glycol units. It is a block copolymer whose soft segment is polyether containing 80 mol% or more of As the polyester unit, in addition to the polytetramethylene terephthalate unit, IM or two or more of polymethylene terephthalate units, polypropylene terephthalate units, polyethylene inphthalate units, etc. may be copolymerized in a proportion of up to 20 moles. In addition, as polyether units, in addition to poly(tetramethylene ether) glycol units, up to 20 mol% of one type or 211 or more of polyethylene ether glycol units, polypropylene ether glycol units, polyhexamethine/ether glycol units, etc. are copolymerized. may have been done. In addition, the copolymerization components of the hard segment and the soft segment are not limited to those exemplified above, and in particular, inphthalic acid, dimer acid, 3,5-
A product using di(carbomethoxy)benzenesulfonic acid metal salt as a copolymerization component is practically useful in terms of cost reduction or dyeing factory when a copolymerization component is used.

Among these, the most preferred is a polyester fist polyether block copolymer having polytetramethylene teretelate as a hard segment and polytetramethylene ether glycol apricot knot segments. The copolymerization ratio (weight) of the aromatic polyester as a hard segment and the polyalkylene ether glycol as a soft segment is 65:35 to 95:5.
is preferable, more preferably 75:25-90:
10 is good. That is, it is characterized by a larger amount of hard segments than the copolymerization ratio normally used as a thermoplastic elastomer for chemical product applications.

Further, the number average molecular weight of the polyalkylene ether glycol is preferably 5° to 4,000, more preferably 1,000 to 2,000 from the viewpoint of increasing the melting point of the fiber.

Further, the ethylene terephthalate polyester used in the present invention has an intrinsic viscosity IV of 0.7 or more. This is because the initial tensile modulus of the fibers obtained by the method of the present invention using ethylene terephthalate polyester with an IV of less than 0.7 is lower than that of the fibers obtained by the conventional method. This is because you can't get something high enough.

Hereinafter, the method for producing the deposited ethylene terephthalate polyester fiber of the present invention and the characteristics of the fiber will be described in more detail.

In the present invention, an ethylene terephthalate polyester polymer having an intrinsic viscosity IV of 0.7 or more and a polyester-
After drying the polyether and block copolymer under vacuum, they are blended in the form of chips. The vacuum drying temperature is preferably higher than the glass transition temperature and lower than the fusion temperature.

If the raw material polymers are not subjected to vacuum drying temperature, hydrolysis will occur and the intrinsic viscosity (v) will drop significantly, making it impossible to obtain the desired high modulus polyester fibers, which is not preferred.

The blending ratio of the polyester/polyether block copolymer polymer to be blended with the ethylene terephthalate type polyester polymer is 0.2 to 15% by weight, preferably 0.2 to 10% by weight. If the blend ratio is less than 0.2% by weight, the high elastic modulus that is superior to ethylene terephthalate polyester fibers that do not contain polyester/polyether block copolymer cannot be obtained. Undesirable.

On the other hand, if the blending ratio exceeds 15% by weight, the spinning state becomes unstable during the spinning stage, the thickness unevenness in the length direction of the resulting yarn becomes large, and both the initial tensile modulus and tensile strength decrease, which is preferable. do not have.

The blended polymer chips as described above are melt-extruded at a temperature of at least 20° C. or higher than the melting point of the ethylene terephthalate polyester polymer.

The melt extrusion method is not particularly limited, but
An extruder type extruder, a piston type extruder, a twin-screw kneading type extruder, etc. are used.

As a condition for extruding the material through the nozzle orifice from the extruder, it is preferable to set the shear rate to I x 10'sec'' or less.

Here, the shear rate te is calculated using the following formula.

It is.

When n exceeds I x 10'5ec-', melt fracture or its precursor phenomenon occurs, making it difficult to improve the physical properties.

The polyester yarn extruded in this way is then prepared.

If the birefringence Δn of the yarn is less than 0.020, it is not preferable because it will be difficult to achieve a high elastic modulus in the subsequent drawing step even if high-magnification drawing is achieved.

The undrawn polyester fiber thus obtained was
Stretching is carried out by (100+NE)/100 times or more at a temperature of .degree. C. or lower.

Here, NE refers to the natural draw ratio of the undrawn yarn.

If the stretching temperature exceeds 80° C., crystallization will proceed before stretching, impeding stretchability.

Following low-temperature stretching, stretching is performed at a temperature range of 150-250''C.

Multi-stage stretching is preferable for high-temperature stretching, first 150 to 200
The first stage stretching is carried out at a temperature range of 200-25°C.
It is preferable to perform two or three or more stages of stretching within a temperature range of 0°C.

Furthermore, it is preferable to subsequently perform a relaxation heat treatment of 10% or less at a temperature of 100 to 220'C. The relaxing heat treatment allows for a more perfect molecular weight alignment of the crystalline regions and promotes the initial tensile modulus factory effect of the method of the present invention.

When the relaxation rate of the relaxation heat treatment exceeds 10%, it becomes difficult to increase the tensile strength to 8 g/d or more.

If the relaxation temperature is 100° C., the rearrangement of molecular chains in the crystalline region will be insufficient. Furthermore, when the relaxation temperature exceeds 220°C, both the strength and modulus decrease.

The polyester fiber thus obtained is a polyester fiber.
0.2-15% by weight of polyether block copolymer
It is made of ethylene terephthalate polyester and has an initial tensile modulus of 150 g/d or more, preferably 1
exhibits eOg/d or more, and has a tensile strength of 8 g/d or more,
A high strength polyester fiber with a high elastic modulus, preferably 9 g/d or more, which is superior to ethylene terephthalate polyester not containing a polyester/polyether block copolymer, is provided.

Note that the higher the cutting strength and initial tensile modulus of the high-modulus high-strength polyester fiber of the present invention are, the more desirable; however, from the viewpoint of manufacturing technology, the limit for the cutting strength is 30 g/d, and the initial tensile modulus is 500 g/d. It is assumed that this is the case.

(Function) The fiber of the present invention has an excellent property of high tensile modulus because by adding an appropriate amount of polyester/polyether block copolymer to ethylene terephthalate polyester, the copolymer is It is thought that it plays the role of a plasticizer and helps stretch the polyester molecular chain to a high degree. It is presumed that when the content of the copolymer increases, a reaction with the polyester component occurs, and the polyester no longer has the properties as a polyester, resulting in a decrease in the properties of high tensile modulus.

The most important point in achieving a highly stretched molecular chain arrangement using the method of the present invention is to add a polyester/polyether block copolymer to ethylene terephthalate polyester, perform melt spinning, and apply appropriate stretching conditions. From this consideration, it is surmised that this is due to the high degree of orientation.

(Examples) Examples are shown below, but the present invention is not limited to these Examples.

The method of measuring physical property values used for evaluation of the present invention is as follows.

Measuring Method of Intrinsic Viscosity IV> In the present invention, the intrinsic viscosity IV of ethylene terephthalate polyester is the intrinsic viscosity [η] measured at 30°C using a mixed solvent of P-chlorophene/tetrachloroethane=371. is converted into the intrinsic viscosity IV of phenol/tetrachloroethane=80/40 using the following formula.

I V = 0.8325X (77) +0.005
Measuring method of fiber fineness〉 Ibro type fineness measuring device DENIER COMPUTER DC
- Fineness of single fiber (denier, d) using type 11B
was measured.

However, the length of the fiber measurement sample was 80 cm.

<Measurement method of tram strength> Tensile strength of fiber (11f) is JIS-1, -101
3 (1981), the tensile strength of single fibers was measured in a test room under standard conditions using a constant speed extension type universal tensile tester TENSILON UTM-m manufactured by Toyo Baldwin ■. .

However, the measurement conditions were as follows: using a 5 kgf tensile load cell,
The sample was pulled at a pulling speed of 10a/min (extension speed of 100% of the gripping interval per minute) and a recording paper feed rate of 0.17 minutes, and the load when the sample was cut (g
f) and calculate the tensile strength gf/d)jt using the following formula:
It was calculated and set as fiv (g/d).

Measuring method of initial tensile modulus of fiber> The initial tensile resistance (initial tensile modulus) of fiber is determined by JIs-
The test was conducted using the same method as the above method for measuring fiber strength according to 7.5.1 of L-1013 (1981), and a load-elongation curve was drawn on the recording paper. From this figure, JIS-L-1
Calculate the initial tensile resistance (gf/d>) according to the initial tensile resistance calculation formula described in 7.10 of 013 (1981),
It was defined as the initial tensile modulus (g/d).

<Method for measuring birefringence (△n)> Nikon polarizing microscope - P OH type Line Co., Ltd. Perec compensator was used, and the light source was a spectral light source activation device (Toshiba 5LS-8-B type) (Na light source).

A sample cut at an angle of 45° to the fiber axis with a length of 5 to 6 mm is cut onto a glass slide with the cut side facing upward.

Place the sample slide glass on the rotating stage, adjust the rotating stage so that the sample is at a 45° angle to the polarizer, insert the analyzer, set the dark field, and set the compensator to 30°. count the number of stripes (n pieces). Turn the compensator in the right-hand direction to find the point at which the sample first becomes darkest / Compensator scale A1 / Turn the compensator in the left-hand direction to find the point at which the sample first becomes darkest After measuring scale b-t- (61/1
0 scale), return the compensator to 30, remove the analyzer, measure the diameter d of the sample, and calculate the birefringence (Δn) based on the formula below (is constant 2
0 average).

Δn=r'/d(rniretardage3n,=nλo
+ε)λφ=589.8mμ C/100 of compensator manual of 82947 company
1 determined from 00 and i = (a-b) (: difference in convensator reading) Specific examples of Examples and Comparative Examples are shown below. Polymers similar to Examples 1 to 5 and Comparative Examples 1 to 3 are It is as follows.

Ethylene phthalate polyester has an IV of 1.
0 polyester chips for tire cords were used.

As a polytetramethylene glycol and polybutylene terephthalate copolymer, the molar fraction of polytetramethylene glycol and polybutylene terephthalate is 25.5.
: A ratio of 74.5 was used.

The drying conditions for each polymer are shown in Table 1 below.

Table 1 Example I Vacuum-dried ethylene terephthalate polyester polymer, polytetramethylene glycol, and polybutylene terephthalate copolymer polymer in a weight ratio of 99.5:
Blend in the form of chips in Step 1, and use an extruder type spinning machine at a spinning temperature of 305°C and a single hole discharge rate of 1.5 g/Il+.
Melt extrusion was carried out through a nozzle with a hole diameter of 0.4mm/sec under conditions of
It was wound up at m/min. Birefringence Δ of the obtained undrawn yarn
n is 0.052, and the natural stretch ratio (NE) is 21%
Met.

Next, the undrawn yarn was stretched 1.21 times at room temperature (stretching speed 22.2 m/min), then at 160°C at a stretching ratio of 1.56 times, and at 245°C at a stretching ratio of 1.14 times at a stretching ratio of 2. It was stretched in stages (3 stages in total).

The fiber physical properties of the obtained drawn yarn were 35.0 denier, tensile strength 9.20 g/d, and initial elastic modulus 157.8 g/d.

Example 2 A vacuum-dried ethylene terephthalate polyester polymer, a copolymer of polytetramethylene glycol and polybutylene terephthalate were blended in the form of chips at a weight ratio of 98:2, and the mixture was spun at a spinning temperature of 305°C using an extruder type spinning machine. Melt extrusion was carried out through a nozzle with a hole diameter of 0°4 mmφ under the condition of single-hole discharge rate of 1.5 g/win, and after cooling and solidifying with cooling air of 0.35 m/sec, about 1% of the yarn was extruded. Apply oil and spin speed 250
It was wound up at 0 m/1n. The birefringence Δn of the obtained undrawn yarn was 0.0295, and the natural draw ratio (NE) was 5.
It was 1%.

Next, the undrawn yarn was drawn 1.51 times at room temperature (drawing speed 1f20.9 m/min), and then at 160°C at a drawing ratio of 1.69 times and at 245°C at a drawing ratio of 1.07 times. It was stretched in two stages (total of three stages).

The fiber physical properties of the obtained drawn yarn were 32.0 denier, tensile strength 9.73 g/d, and initial elastic modulus 175.9 g/d.

Example 3 A vacuum-dried ethylene terephthalate polyester polymer, a copolymer of polytetramethylene glycol and polybutylene terephthalate were blended in the form of chips at a weight ratio of 98:2, and the mixture was spun at a spinning temperature of 305° C. using an extruder type spinning machine. Single hole discharge m 1.5 g/
Melt extrusion was performed through a nozzle with a hole diameter of 0° and 41 mm under conditions of It was wound up at a speed of 0.00 m/min. The birefringence index of the obtained undrawn yarn was 0.0578, and the natural draw ratio (NE) was 14%.

Next, the undrawn yarn was stretched 1.14 times at room temperature (stretching speed 21.1 m/min), then at 160°C at a stretching ratio of 1.66 times, and at 245°C at a stretching ratio of 1.08 times at a stretching ratio of 2 It was stretched in stages (3 stages in total).

The fiber physical properties of the obtained drawn yarn were 30.6 denier, tensile strength 9.38 g/d, and initial elastic modulus 166.9 g/d.

Example 4 A vacuum-dried ethylene terephthalate polyester polymer, a copolymer of polytetramethylene glycol and polybutylene terephthalate were blended in the form of chips at a weight ratio of 98:2, and the mixture was spun at a spinning temperature of 305°C using an extruder type spinning machine. Melt extrusion was performed through a nozzle with a hole diameter of 0° and 4 fins under the conditions of a single hole discharge rate of 1.5 g/layer in, and after cooling and solidifying with cooling air of 0.35 m/sec, the yarn yield was approximately 1 % oil agent and spinning speed 3900 m
/mtn. Birefringence Δn of the obtained undrawn yarn
was 0.0728, and the natural stretch ratio NE was 11%.

Next, the undrawn yarn was stretched 1.11 times at room temperature (stretching speed 21.9 m/min), then at 160"C at a stretching ratio of 1.65 times, and at 245°C at a stretching ratio of 1.05 times at a stretching ratio of 2. It was stretched in stages (3 stages in total).

The fiber physical properties of the obtained drawn yarn were 30.4 denier, tensile strength al'9.04 g/d, and initial elastic modulus 167.8 g/d.
It was d.

Example 5 A vacuum-dried ethylene terephthalate polyester polymer, a copolymer of polytetramethylene glycol and polybutylene terephthalate were blended in the form of chips at a weight ratio of 98:2, and the spinning temperature was 305°C using an extruder type spinning machine. , single hole discharge f11.5 g/
Under win conditions, melt extrusion was performed through a nozzle with a hole diameter of 0.4 mm, and after cooling and solidifying with cooling air at 0.35 m/sec, approximately 1% oil was applied to the filament, and the spinning speed was 450.
It was wound up at 0 m/+win. The birefringence Δn of the obtained undrawn yarn was 0°0976, and the natural draw ratio (NE)
was 4%.

Next, the undrawn yarn was stretched 1.04 times at room temperature (stretching speed [27.7 m/min), and then at a stretching ratio of 1 at 160°C.
, 51 times, two-stage stretching at 245°C and a stretching ratio of 1.07 times (
A total of 3 stages of stretching) were performed.

The obtained drawn yarn had fiber physical properties of 27.8 denier, tensile strength of 8.38 g/d1, and initial elastic modulus of 186.1 g/d.

Comparative Example 1 Vacuum-dried ethylene terephthalate polyester was melt-extruded using an extruder-type spinning machine under conditions of a spinning temperature of 305°C and a single-hole discharge rate of 1.5 g/win through a nozzle with a hole diameter of 0.4*mφ. Q. After cooling and solidifying with cooling air at 35 m/sec, approximately 1% oil was applied to the yarn and the yarn was wound at a spinning speed of 2500 m/1n. The birefringence Δn of the obtained undrawn yarn was 0.0404, and the natural draw ratio (NE) was 15%.

Next, the undrawn yarn was stretched 1.15 times at room temperature (stretching speed 22.2 m/min), and then at a stretching ratio of 1 at 160°C.
．． 52 times, two-stage stretching at 245°C and a stretching ratio of 1.14 times (
A total of 3 stages of stretching) were performed.

The fiber properties of the obtained drawn yarn were 38.3 denier and tensile strength 9.8! g/d, and the initial elastic modulus was 154.3 g/d.

Comparative Example 2 A vacuum-dried ethylene terephthalate polyester polymer, a copolymer of polytetramethylene glycol and polybutylene terephthalate were blended in the form of chips at a weight ratio of 98:2, and the mixture was spun at 305°C using an extruder type spinning machine. Single hole discharge f11.5 g/win
Melt extrusion was performed through a nozzle with a hole diameter of 0° and 4.1φ under the following conditions, and after cooling and solidifying with cooling air of 0.35 m/sec, approximately 1% oil was applied to the filament and the spinning speed was 15.
It was wound up at a speed of 0.00 m/min. The birefringence Δn of the obtained undrawn yarn was 0.0112, and the natural draw ratio (NE)
was 115%.

Next, the undrawn yarn was stretched 2.15 times at room temperature (stretching speed 21.13 m/min), and then stretched at a stretching ratio of 1.61 times with IEiO'C and 2 times at a stretching ratio of 1.05 times at 245°C. It was stretched in stages (3 stages in total).

The fiber physical properties of the obtained drawn yarn were 41.4 denier and tensile strength 7. The initial elastic modulus was 138.8 g/d.

Comparative Example 3 Vacuum-dried ethylene terephthalate-based polyester polymer, polytetramethylene glycol, and polybutylene terephthalate copolymer polymer at a weight ratio of 80:
Blend in the form of chips at 20°C, and use an extruder type spinning machine at a spinning temperature of 305°C and a single hole output rate of 1.5g/wi.
Melt extrusion was performed through a nozzle with a hole diameter of 0.4 s + mφ under the conditions of n, and after cooling and solidifying with cooling air at 0° 35 m/sec, approximately 1% oil was applied to the yarn and the spinning speed was 2000.
It was wound up at m/min. The birefringence of the obtained undrawn yarn is 0.0217, and the natural draw ratio <NE) is 22.
%Met.

Next, the undrawn yarn was stretched 1.22 times at room temperature (stretching speed 22.2 m/min), and then at a stretching ratio of 1 at 160°C.
．． 78 times, two-stage stretching at 245°C and a stretching ratio of 1.04 times (
A total of 3 stages of stretching) were performed.

The fiber physical properties of the obtained drawn yarn were 28.6 denier, tensile strength 7.04 g/d, and initial elastic modulus 139.9 g/d.

The details of the stretching conditions in Examples 1 to 5 and Comparative Examples 1 to 3 are shown in Table 2 below.

Furthermore, Table 3 shows the properties of the drawn yarns obtained in Examples 1 to 5 and Comparative Examples 1 to 3.

Margins below (Effects of the Invention) According to the present invention, high strength and high elastic modulus of ethylene terephthalate polyester fibers, which could not be achieved using conventional techniques, can be achieved, especially based on the melt spinning method. In addition, it is possible to provide a high-strength, high-modulus polyester fiber that exhibits a novel fiber II structure that is clearly distinguished from conventional ethylene terephthalate-based polyester fibers.

The fiber of the present invention has significantly improved tensile strength and tensile modulus, and when used particularly for rubber reinforcement purposes such as tire cords, it not only improves the reinforcing effect but also improves tire cord structures such as less bridle and less end. It has the potential to be radically streamlined.

In addition to these properties, the fiber of the present invention can also be expected to have high abrasion resistance and high fatigue resistance due to its high molecular weight, so it can be used for tire cords, belts, waterproof fabrics, hoses, etc. that require elasticity, heat resistance, etc. It is useful as a material for all kinds of industries.

Procedural amendment (voluntary) May 6, 1988 1. Indication of the case High elastic modulus high strength polyester fiber and its manufacturing method 3. Person making the amendment Relationship to the case Patent applicant 2-2 Dojimahama, Kita-ku, Osaka Column 5 of Detailed Description of the Invention in Specification No. 8, Contents of Amendment (1) Page 33 of the specification will be replaced with page 33 of the attached sheet.

Claims (9)

[Claims] (1) High elastic modulus made of ethylene phrephthalate polyester containing 0.2 to 15% by weight of polyester-polyether block copolymer, and characterized by having the following properties (a) to (b). High strength polyester fiber. (a) Initial tensile modulus (g/d)≧150 (b) Tensile strength (d/d)≧8 (2) The high elastic modulus high strength polyester fiber according to claim 1, wherein the fiber has an intrinsic viscosity IV of 0.7 or more. (3) The high-modulus, high-strength polyester according to claim 1 or 2, wherein the polyester-polyether block copolymer is a block copolymer consisting of polybutylene terephthalate and polytetramethylene ether glycol. fiber. (4) High elasticity according to any one of claims 1 to 3, wherein the content of the polyester/polyether block copolymer in the ethylene terephthalate polyester is 0.2 to 10% by weight. High strength polyester fiber. (5) The high-modulus, high-strength polyester fiber according to any one of claims 1 to 4, wherein the fiber has an initial tensile modulus of 160 g/d or more. (6) After blending a polyester-polyether block copolymer polymer at a ratio of 0.2 to 15% by weight with an ethylene terephthalate-based polyester polymer having an intrinsic viscosity IV of 0.7 or more, the ethylene terephthalate-based polyester polymer It is melted at a temperature above the melting point, extruded through a nozzle orifice, cooled and solidified, and taken off so that the birefringence of the taken-up yarn is 0.020 or more, and either continuously during spinning or after once wound up at 90°C. A method for producing a high-modulus, high-strength polyester fiber, which comprises stretching at the following temperature at least at a stretching ratio given by the following formula (c), and then further stretching at a temperature range of 150 to 250°C. (c) Stretching ratio = 100 + NE/100 (However, NE indicates the natural stretching ratio (%) of undrawn yarn.) (7) The method for producing a high-modulus, high-strength polyester fiber according to claim 6, wherein the polyester-polyether block copolymer is a block copolymer consisting of polybutylene terephthalate and polytetramethylene ether glycol. . (8) The method for producing a high-modulus, high-strength polyester fiber according to claim 6 or 7, wherein the blending ratio of the polyester-polyether block copolymer is 0.2 to 10% by weight. (9) The method for producing a high-modulus, high-strength polyester fiber according to any one of claims 6 to 8, wherein a relaxation treatment of 10% or less is performed at a temperature of 100 to 220° after the final stretching.