JPH03161509A - Polyester fiber for reinforcing rubber - Google Patents

Abstract

PURPOSE:To obtain the title fiber consisting of a polyester using an antimony compound and germanium compound as a polymerization catalyst, having specific physical property, good dimensional stability, high strength and excellent endurance. CONSTITUTION:The aimed fiber consisting of a polyester obtained by using 30-150ppm, preferably 80-120ppm antimony compound and 5-120ppm, preferably 6-30ppm germanium compound as a polymerization catalyst and having characteristics having (A) <=25eq/ton, preferably <=21eq/ton content of carboxyl terminal group, (B) <=1.3wt.%, preferably <=1.1wt.% diethylene glyool content (DEG), (C) <=12.0%, preferably 0.95-1.3 intrinsic viscosity, (D) <=12.0%, preferably 8-10% dimensional stability (intermediate elongation + dry heat shrinkage) and (E) <=50g/d, preferably <=35g/d terminal modulus (Mt).

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to polyester fibers for rubber reinforcement. More specifically, the present invention relates to polyester fibers for reinforcing rubber that have good dimensional stability, high strength, and excellent durability.

[Prior Art] Polyester fibers have excellent mechanical properties, dimensional stability, and durability, and are widely used not only for clothing applications but also for industrial applications. Among these, it is widely used in rubber reinforcement applications such as tire cords, taking advantage of its characteristics. For tire cord applications, high-strength raw yarn made by drawing low-oriented undrawn yarn at a high ratio has been used, but in recent years, relatively highly oriented undrawn yarn (
Raw yarn obtained by drawing so-called POY has come to be used. This technology was born from the need to improve tire performance, especially uniformity, even if the strength was slightly sacrificed (1f1).

However, in recent years, in order to further improve the performance of tires,
\1 High strength and toughness while maintaining stability
TJ-ru tie A7 code request is high:L. In response to such demands, for example, Japanese Patent Application Laid-open No. 1988-120 describes an example of low-speed stretching of POY, but such stretching technology cannot improve the toughness (strength/stretchability product) of the fiber itself. (It is not a revolutionary increase in strength, but it is great for satisfying the required level of strength and toughness. In order to achieve toughness, it is necessary to It is thought that it is effective to reduce defects.In other words, various defects (foreign objects) exist in tire cords, but these defects are mainly caused by particles present in the polymer.
Many of these particles are caused by polymerization catalysts, and it is necessary to fundamentally eliminate such particles.

Regarding catalysts that have been used to date to produce polyester fibers for rubber reinforcement, for example, Japanese Patent Publication No. 37-58
No. 21 discloses a catalyst system of manganese acetate, anddimon dioxide, and phosphoric acid, and JP-A No. 55-12871 discloses an example of calcium acetate, antitium dioxide, and phosphorous acid. The publication contains examples of lithium acetate, antimony trioxide, and phosphorous acid. When polymerization is carried out using these catalysts, a large number of catalyst C particles are generated, and fibers that meet the recent high strength and toughness requirements cannot be obtained because of defects caused by lint cloth.

[Problems to be solved by the invention] The Ministry of the Invention and others have conducted fundamental studies from the viewpoint of the BORIMA, in order to obtain a boris-al fiber that has good dimensional stability, strength and toughness, and is dimensionally stable. Polyester fibers for rubber reinforcement that have good properties, heat resistance, and durability have been developed.

1] A Thousand Steps to Solve the Problems] The object of the present invention as described above is to reduce the amount of antimony compound and germanium 7m to 1.2 to 5-120ppm. This can be achieved by using polyester fibers for rubber reinforcement, which are made of polystellate using a germanium compound as a catalyst and have the following properties.

A, Carboxyl terminal group amount (C O OH )C
O O H≦25e! ]/τon B. Diethylene glycol content (DEG) DEG≦1
．． 3wt%C. Intrinsic viscosity (iV) IV≧0.85 I) 1-method stability (S) (intermediate elongation and dry heat shrinkage rate) S≦
12.0%E. Terminal mosieras (Mt) Mt≦50g/d What is the polyester of the present invention? -1・
The main repetition is 1. Single crying II: Zurubori] Nisjru. In order to improve the dimensional stability and strength of polyester Toshino, by-products 1. Substantially contains additives such as the addition of a third component other than tylenegriny, copolymerization, and non-silicone particles (
It is preferable to use no Borieburen I'rephthalate 1.

In order to achieve high strength and high toughness while maintaining good dimensional stability, the present inventors have conducted intensive studies on the factors that reduce the strength of fibers. In particular, it was discovered that the particles were particles originating from catalysts.Furthermore, among these particles, the metal annamonium was recovered by reduction from the antimony compound used in the polymerization catalyst. They discovered that it gives strength and toughness a negative impact.

Therefore, as a result of intensive investigation into the reduction of this sclerotic anti', we found that by using an antimony compound and a germanium compound together as a polymerization catalyst, other polymer properties such as the amount of carboxyl powder and diethyl non-glycol were inhibited. It has been found that the amount of foreign substances in Kotona Ku-12 can be reduced.

Therefore, in the present invention, it is necessary to use an antimony compound and a germanium compound together as a polymerization catalyst. In order to obtain a target IV polymer in a normal polycondensation time, there is a limit to reducing the amount of antimony compound used alone, and therefore there is a natural limit to reducing the amount of antimony metal. Further, if only a germanium compound is used, the amount of diethylene glycol increases, and the dimensional stability of the yarn deteriorates. As the antimony compound used as a polymerization catalyst, antimony trioxide and antimony pentoxide are preferably used, and as the germanium compound, germanium dioxide is preferably used. The amount of antimony compound contained in the polyester fiber of the present invention needs to be 30 to 150 ppm as antimony. If the amount of the antimony compound is less than 30 ppm, a large amount of the germanium compound used in combination must be used in order to maintain polymerization reactivity, which not only increases cost, but also increases the amount of diethylene glycol and reduces dimensional stability.

If the amount of the antimony compound exceeds 150 ppm, it is impossible to reduce metallic antimony by using a germanium compound in combination, and the strength and toughness of the yarn cannot be improved. Also, the amount of germanium compound is 5 as germanium.
~120 Dpm is required. If the amount of germanium compound is less than 5 ppm, reduce the amount of antimony compound used to maintain polymerization reactivity to 150 ppm.
It cannot be less than m. Furthermore, if the germanium content of the germanium compound exceeds 120 ppm, not only the manufacturing cost will increase significantly, but also the DEGII will increase and the dimensional stability will deteriorate. From this point of view, the amount of antimony in the antimony compound is preferably 40 to 120 ppm, and 8
The amount of germanium is preferably 5-800 pm, and 6-30 pm.
! ) Dm is more preferred. The polymer of the present invention can be produced either by direct polymerization or by dimethyl terephthalate-mediated production, the so-called DMT method. When producing by the DMT method, it is preferable to use a manganese compound as the transesterification catalyst. Note that lithium compounds, magnesium compounds, and the like are not preferred because they generate particles in the polyester.

The carboxyl terminal group i (
COOH) needs to be 2 5 eg/ton or less. If COOHJt exceeds 25 eQ/ton, the rubber deteriorates quickly and lacks durability as a rubber reinforcing material.

From this viewpoint, COOHi is preferably 2 1 eg/ton or less.

Furthermore, the diethylene glycol content (DEG) in the polyester fiber of the present invention needs to be 1.3 wt% or less. When DEC4 exceeds 1.3w7%, not only the dimensional stability of the fiber deteriorates but also the heat resistance in the rubber decreases. From this point of view, the DEG amount is preferably 1.1 wt% or less, and the intrinsic viscosity (IV) of the polyester fiber of the present invention is 0.8.
Must be 5 or more. IV is O. If it is less than 85, fatigue resistance is poor and it cannot be used as a rubber reinforcing material. From this viewpoint, IV is preferably 0.9 or more. Further, from the viewpoint of operational stability such as silk-spinning property, the IV is preferably 1.3 or less.

The dimensional stability (intermediate elongation, dry heat shrinkage) of the polyester fiber of the present invention must be 12% or less. If the dimensional stability exceeds 12%, the dimensional stability of the cord during tire molding will be poor; The uniformity of the tire decreases.From this point of view, the dimensional stability is preferably 10% or less.In addition, from the viewpoint of ease of manufacturing, the dimensional stability is preferably 8% or more.

Furthermore, the terminal modulus of the polyester PAH of the present invention must be 50 g/d or less. When the terminal modulus exceeds 50 g/d, the strength retention rate during twisting is low, and even if the strength of the yarn is increased, the strength of the tire cord cannot be increased. From this point of view, the terminal modulus is preferably 3 5 g/d or less.

As mentioned above, by using an antimony compound and a germanium compound together as a polymerization catalyst and by strictly controlling their concentration, the generation of particles caused by the catalyst can be suppressed, and it is possible to suppress the generation of particles caused by the catalyst.
A polymer with good retention properties such as O O H amount and DEG amount can be obtained. For the first time ever, it was possible to manufacture polyester machines with unprecedented high performance using such a volima.

In other words, as mentioned above, in the present invention, it is an object of the present invention to reduce as much as possible the amount of antimony produced by the reduction of the andimony compound used in the polymerization catalyst and (in). This is important in order to obtain a polyester fiber for rubber reinforcement with good durability.

According to the research conducted by the present inventors, it is preferable to reduce the content of the antonium metal produced by reduction of the polymerization catalyst and the andimony compound used in step 1 to 5 ppm or less (it is preferable to improve durability and toughness, and The following is more preferable: Polymerization conditions (time,
It is preferable to strictly control the temperature (temperature).
It is preferable to suppress the reduction reaction by applying chrome plating or Teflon coating to the piping and back parts. Further, rubber reinforcing materials such as tire cords are required to have good dimensional stability (while maintaining intermediate elongation and dry heat shrinkage at a low level 11a) and to improve toughness.

The inventors of the present invention have conducted extensive studies regarding these requirements, and have found that it is important to strictly control the addition method, performance, and type of phosphorus compound used during polymerization to meet the above requirements. Phosphorus compounds are generally used to improve the heat resistance of volima, but it is a surprising fact that phosphorus compounds influence the relationship between the dimensional stability and toughness of fibers as described above. As a result of their research, this is a new finding.

As a result of the research conducted by the present inventors, it was found that a phosphorus compound (phosphoric acid) was used, and the residual content was reduced to 10-40 ppm.
, and it has been found that it is preferable to add it at the beginning of polycondensation. By using such a phosphorus compound, the toughness of the fiber can be increased for the same dimensional stability.

'g' Straw strength elongation product ('T ./Tl''') (intermediate elongation ten-dry yield) + 22.0 Since the fiber with high toughness is 11 with the same dimensional stability, Like (noi)

The reason for the effectiveness of the phosphorus compound is not clear, but the present inventors believe that it is due to the thickening effect of the trifunctional phosphorus compound of phosphoric acid, which controls the formation of the fiber structure during spinning. Above) By using polyester fiber m that satisfies <Tff≧S+22.0 as shown in E, the fatigue resistance can be significantly improved compared to the conventional method.

Specifically, the polyester fiber of the present invention can be produced by the following method.

The polycondensation reaction is carried out using an antimony compound and a germanium compound as a polymerization catalyst. In this case, it is preferable to use phosphoric acid as the phosphorus compound and add the phosphoric acid to the initial stage of polycondensation before addition of the andimony compound and the germanium compound. During polycondensation, the amount of preparation, polymerization temperature, and polymerization time are appropriately selected.
~1≦26eMton, DEG≦L 3wt% polyethylene terephthalate 1~ chip is obtained.

The chips thus obtained were subjected to solid phase polymerization according to a conventional method, and [
COOH]≦16eMton, IV 1 .
Polyethylene terephthalate with a weight of 0 or higher is melted and then slowly cooled in a heating zone for 1 time, then cooled and solidified in a chimney wind. At this time, the piping and back parts in the spinning machine are coated with chrome. Plating (No. Antimony metal precipitation (reduction)
Also, it is preferable to use a metal wire (SUS) non-woven fabric with an absolute diameter of 30 μm or less as a door filter. In addition to reducing the amount of nitrogen contained in the nitrogen and the amount of nitrogen in the spinning machine as much as possible, we also conducted a chimney-style air passage.
It is more preferable to reduce the amount of hair loss. It is preferable to maintain the amount of filtrate present in the yarn at a level of 800 pieces/mg or less, more preferably 91,500 pieces/mg or less, in order to improve toughness and durability.

The yarn thus discharged from the nozzle was taken at a speed of 1000 m/
min or more, preferably 2000m/min or more 4000m
Highly oriented spinning at less than /min.

After spinning this undrawn yarn or winding it once,
Hot roller stretching is performed and heat set at a temperature of 220°C or higher. At this time, the stretching ratio and relaxation rate are appropriately stabilized so that the terminal modulus is 5 0 C)/d or less.

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

Note that the physical properties in the examples were measured as follows.

A. The amounts of metals (antimony, germanium, phosphorus, etc.) in the bolimar and ti&M were determined by a fluorescent X-ray method.

B. Amount of carboxyl terminal group (Coo) was determined by dissolving 0.5 g of a sample in 10 d of O-cresol, cooling it after complete dissolution, adding chloroform 3-, and performing potentiometric titration with a metal solution of NaO.

C. After the DEG shop sample was subjected to alkali decomposition, it was quantified using gas chromatography.

D. Strong elongation, intermediate elongation, terminal modulus 1 lath using Toyo Baldwin Tensilon tensile tester, test length 25
cm, an SS curve was obtained at a take-up speed of 30 cm, and the strength elongation was calculated.

Further, from the same SS curve, the elongation corresponding to the strength of 4.5 g/d was read to determine the intermediate elongation.

The terminal modulus was determined by dividing the difference between the stress at the point where 2.4% was subtracted from the cutting elongation and the breaking stress by 2.4 x 10-''.

E. Dry heat shrinkage rate ΔSd Take the sample in the form of a skein and place it in a temperature-controlled room at 20°C and 65% R for 24 hours.
After leaving it for more than an hour, the length was measured by applying a load equivalent to 0.1q/d of the sample. After leaving the sample o in an oven at 150°C for 15 minutes without tension, take it out of the oven and leave it in the above @adjustment for 4 hours, apply the above load again, and calculate the measured length from the following formula. Calculated by.

ΔSd=(Qo-0.1)/D. ox100 (%
)F. Number of Foreign Matter in Threads The sample was divided into single threads, and sampled by placing them on a slide glass so that they did not sag (length: 6 cm).
) using an Olympus optical microscope (phase contrast method),
Scan at 200x magnification and count the number of foreign objects in the thread.

Repeat the measurement with 5 measurements to find the average value × (pieces/6 cm 2 ), and convert this value to the number of foreign particles per mg.

G. Intrinsic viscosity (IV) At a temperature of 25°C, orthocrophenol (hereinafter referred to as OC)
Dissolve 0.8 tj of the sample in 10- (referred to as P), determine the relative viscosity (ηT) using the following formula using an Ostwald viscometer, and further calculate lV.

ηT=η/η0 −tXd/to xciQIV=0.
02427) T+0.2634η: Viscosity of polymer solution η0: Viscosity of solvent t: Falling time of solution (seconds) d: Density of solution (Q/aj)to: Falling time of OcP (seconds) do: Density of OcP (Q / cTj) Mouth. 740g of antimony metal and 50g of orthochlorphenol (OCP)
0mk: i-dissolved centrifugation (12,000 rpm x 2 hr
) After washing and drying.

The spectrum of the obtained centrifuged grains is measured using an X-ray diffraction device, and metal antimony is determined from the spectrum.

■． Heat resistance in rubber The cord was embedded in rubber and evaluated by strength retention after vulcanization at 150°C for 6 hours. Strong retention rate of 70% or more ◎, 60
~70% is shown as ○, and less than 60% is shown as X.

d. Fatigue resistance (GY life) Tube internal pressure 3.5 K'J according to ASTM-0885
/ ctA, rotation speed 850 rpm, tube angle 9
The rupture time of the tube was determined as 0'.

The results are: ◎ is a conventional product (commercial tire made by Toray Industries, Inc.) 1.00
0-240-703M> O indicates an increase of 1 to 30% compared to the conventional product. Δ indicates a conventional product level.

Example 1 0.035 parts of manganese acetate tetrahydrate was added to 100 parts of dimethyl te1-nophthalate and 50.2 parts of ethylene glycol, and a T transesterification reaction was carried out in a conventional manner. Next, 11 (P.:
Then, 0.0025 part of germanium dioxide (17 ppm of Ge) was added, and 0.0125 part of antimony trioxide (104 ppm of Sb) was added to conduct a polymerization reaction for 3 hours and 10 minutes. .

(Polymerization temperature: 285°C) The intrinsic viscosity (IV) of the obtained bolimar was 0. 72, Carboxyl terminal amount ([COO port]) 17.1 eMton
, DEGO, was 7 wt%.

In addition, the amount of antimony in the obtained bolimar was 100 ppm,
The germanium content was 10 Dpm, and the amount of phosphorus was 2 oppm. The amount of antimony metal in this polymer was 0.3 Dpm.

The above-mentioned volima was pre-dried at 160° C. for 5 hours and then subjected to in-phase polymerization at 225° C. (a solid-phase polymerized chip with IV=1.35 was obtained).

This chip was spun using an Ex1 Heruda type spinning machine at a temperature of 29
Spinning was carried out at 5°C. At this time, a metal non-J cloth with an absolute diameter of 15 μm was used as a filter, and the cap was O. A round hole of 6 mφ was used. In addition, chrome plating was applied to the parts of the bollima piping and back parts that came in contact with the bollima, and the nitrogen for the chimney was passed through a 1μ filter before use.

The thread discharged from the nozzle has a length of 25 cm, an inner diameter of 25 cmφ,
After being slowly cooled in a heating cylinder at a temperature of 300'C, a chimney cooling air was applied to cool and solidify the material, and after oiling, it was taken off at a take-up speed C as shown in Table 1. The obtained undrawn yarn was stretched at a temperature of 90°C.
A drawn yarn was obtained by changing the magnification and relaxation rate at a heat shielding temperature of 240°C.

The number of foreign substances in the yarn of the polyester fiber produced in this way is 1
50 pieces/ffi! 9 to 450 pieces/m'J, and I0
．． To 98-1. OL carboxyl end group is 14eMt
on, DEG was 0.7 wt%.

Next, this drawn yarn was first twisted in the S direction at 49T/10cts.
The first twist was applied at 49T/10rm in the Z direction to form a raw cord.

Next, this cord was coated with adhesive using Convue 1~Rita manufactured by Riller Co., Ltd. to prepare a processing load. The processing conditions are drying temperature 160℃, fixed length treatment, heat treatment temperature 24℃.
The tension treatment was performed at 0°C, and the post-treatment temperature was 240°C for relaxation treatment. By adjusting the tension rate and relaxation rate, the intermediate elongation of the treated cord was set at 3-4%, and the physical properties of raw yarn, raw cord, and loose yarn are shown in Table 1.

As is clear from Table 1, high toughness yarn exceeding the strength/elongation product defined by the present invention (more specifically, Ta≧S+22.
A high toughness raw yarn that satisfies 0 is obtained.

However, Nα1, which has a low take-up speed and a dimensional stability exceeding 12, has unsatisfactory tire uniformity. Also N
(Nα5 yarn was spun under the same conditions as No. 13, but the terminal modulus exceeded 50 by changing the elongation conditions. Although the strength-elongation product of the raw yarn was high, the strength decreased during twisting and dipping, and the toughness of the treated cord was not much different from that of the conventional yarn. Only fibers with Nα of 2 to 4 that meet the range of the present invention had high toughness and good tire uniformity.

Example 2 An undrawn yarn was obtained under the same conditions as Example INα3, using the same polymer as in Example 1 and changing the spinning temperature and residence time to change the amount of carboxyl end groups. As is clear from Table 2, when the amount of carboxyl terminal groups is 25 eg/ton or more, the heat resistance in the rubber deteriorates. Furthermore, diethylene glycol was added during the production of Posoma in Table 2 Example 1 to change the amount of DEG.

Table 3 As shown in Table 3, if the DEG content exceeds 1,3 wt%, the dimensional stability deteriorates and the heat resistance in the rubber also decreases.

Example 3 During the production of the volima of Example 1, the antimony dioxide and germanium dioxide added were changed in Step 1 to obtain IV0.
I got 7 chips. Experiment NQ3 of Example 1 from the above
A polyester machine miscellaneous material was obtained according to the method. The results are shown in Table 4 in terms of volima retention.

(Left below) Bright anti-shine that is clear from Table 4 M M 1 5o
There is a lot of GtSb mel1 in 11,17 exceeding ppm,
It can be seen that the number of foreign substances in the thread increases and the toughness decreases. Also, NQ14 with antimony d less than 30 ppm
has a germanium star concentration of 111 ppm, so its polymerization reactivity is poor (
In order to obtain an IV of 0.7, the polymerization time becomes longer and COOl
1 increased. Therefore, C O O 1-1 in the yarn is 2
8.5F3Q/ton, and the heat resistance in the rubber is unsatisfactory.

On the other hand, NO, 15, in which the amount of antimony was less than 301)Dm and the amount of germanium added accordingly was as large as 180I)DrT1, l)E G m increased and the heat resistance in the rubber was unsatisfactory. Further, when the germanium star is set to less than 5[) m, the polymerization reactivity is poor and the COO opening increases when the antimony star is below 1501) pm. As a result, the COO opening in the yarn is 29,3 eg/ton, and the heat resistance in the rubber is unsatisfactory.

The object of the present invention was achieved only with Nα12 and L3 using an andmone compound with a sb range of 30 to 150 pF) and a Geffi5 to 120 p[Dm germanium compound as a polymerization catalyst.

Example 4 A polymer was obtained in the same manner as in Example 1 except that trimethyl phosphate was used in the same molar amount instead of phosphoric acid as the phosphorus component used in the polycondensation reaction. This volima was spun and drawn in the same manner as in Example INα3 to obtain a drawn yarn with the physical properties shown in Table 6. Table 9 Table 6 As shown in Table 6, when the type of phosphorus was changed, the shrinkage rate when spinning under the same conditions was Approximately 1% higher. Similar to Nα3, a yarn with high toughness can be produced, but when compared in terms of toughness for the same dimensional stability (Nakanaka Juken Yield), it is lower (Tn≧
Nα3 and NQ
The fatigue resistance of both 1 and 8 was superior to that of conventional yarns, but in particular N (13 was Nα1) satisfying T√E≧S+22.0.
It was better than 8.

Example 5 Spinning was carried out under the same conditions as in Example INα3. A commonly used spinning machine was used, and pack parts were those normally used, and no P filter was used. No particular consideration was given to Utosu et al.

The physical properties are listed below 9 (blank below) Table 7 As shown in Table 7, when the spinning conditions are normal, foreign matter in the yarn increases and the toughness is still higher than the conventional product, but NQ3
decreases more than

[Effect of the invention] In the present invention, by specifying the catalyst composition of the polymer and specifying the polyester fiber, for the first time, a yarn for rubber reinforcement with high toughness and good dimensional stability, ripening resistance, and durability has been created. can get. This yarn is particularly suitable for use in tire cords, and can be made with less ends and less ply than conventional cords, making it possible to reduce the weight of tires. Moreover, a tire with good dimensional stability and good uniformity can be obtained.

Claims (3)

[Claims] (1) A polyester fiber for rubber reinforcement, which is made of polyester using as a polymerization catalyst an antimony compound in an amount of 30 to 150 ppm as antimony and a germanium compound in an amount of 5 to 120 ppm as germanium as a polymerization catalyst. A, Carboxyl terminal group amount (COOH) COOH≦25eg/ton B, Diethylene glycol content (DEG) DEG≦1
．． 3wt% C, intrinsic viscosity (IV) IV≧0.85 D, dimensional stability (S) (intermediate elongation + dry heat shrinkage) S≦1
2.0% E, terminal modulus (Mt) Mt≦50g/d (2) The polyester fiber for rubber reinforcement according to claim (1), wherein the number of foreign substances in the yarn as measured by the transmitted light method using an optical microscope is 800 pieces/mg or less. (3) Claim (1) characterized in that the toughness (T√E) and dimensional stability (S) of the fiber satisfy the following formula (I): T√E≧S+22.0 (I); or Claim (2
) Polyester fibers for rubber reinforcement as described.