JPS58203108A - Polyester fiber - Google Patents

Abstract

PURPOSE:The titled fiber that is composed of ethylene terephthalate, satisfying specific values in terminal carboxyls, amorphous orientation and long-period spacing and having high strength, elasticity, heat stability and durability in rubber, thus being suitable for use in reinforcement of rubber structure. CONSTITUTION:A polyester that is composed of ethylene terephthalate and has a terminal carboxyls of 10 equivalent/10<6>g polymer or less, and an intrinsic viscosity of more than 0.85 is melted and extruded in a cooling zone into filaments, rapidly solidified by cooling and taken up at a speed of higher than 1,000m/min. The resultant undrawn filaments are subjected to the first-stage drawing so that the optical birefrigence becomes less than 0.16 in the equatorial reflection of the X-ray broad angle diffraction diagram, then to multi-stage drawing and heat setting to produce the objective filaments of 0.55-0.64 amorphous orientation (fa), 130-160Angstrom long-period spacing (L) and 9.0-15% dry heat shrinkage at 175 deg.C and more than 0.8 intrinsic viscosity.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polyester fiber suitable for reinforcing rubber structures, which has improved thermal properties and mechanical properties at the same time.Polyester fiber has excellent mechanical and thermal properties. Therefore, it is used not only in the clothing field, but also in tire coats, conveyor belts, and seat belts.

It is widely used as an industrial fiber for V-belts, hoses, sewing threads, etc. Especially in recent years, the relative weight of industrial fibers has become higher than that of clothing, and as a result, industrial fibers,
In particular, the required properties for fibers for reinforcing rubber structures are becoming stricter.

Conventional methods for producing fibers for reinforcing rubber structures are directed toward improving cutting strength, and for this purpose, the intrinsic viscosity [η] of the polymer is increased to 0.7 or higher, and its f! - In the spinning process, spinning conditions were adopted that minimized the birefringence Δn of the undrawn yarn, followed by sufficient stretching and heat treatment.

The fibers obtained by smelting can be cut as originally intended! 1
Although it is excellent in terms of strength, it has very specific uses.
For example, it is not designed for radial tires that require low heat shrinkage and high modulus.

That is, at present, for radial tires, rayon is preferably used which has a low #-1t1 cutting strength but a low heat shrinkage rate and a high modulus.

However, the production of rayon itself is limited, the price is high, and there are problems in terms of stable supply in the future.

Therefore, we used polynisdel fiber to further reduce the heat shrinkage rate.
Some studies have also been made to increase the modulus. A typical example is one in which a relaxation heat shrinkage treatment is performed following the ti stretching step. However, in this case, since the amorphous portion is stabilized, that is, the degree of orientation of the amorphous portion is reduced, the objective of lowering the thermal shrinkage rate is satisfied, but there is a drawback that the modulus becomes lower.

We also considered lowering the intrinsic viscosity [η] of the polymer as another means, but this type of fiber is doubled, twisted, woven into a sag, and treated with a resorcinol-formalin-based adhesive. The heat shrinkage and modulus up to the heat treatment process meet the purpose, but after the rubber is applied and vulcanized and the tire is formed, it is inferior in terms of strength and durability during tire running, and is not suitable for practical use. The problem is big.

Attempts have been made to reduce the amount of terminal carboxyl groups in order to suppress the decrease in cord strength in the rubber, but this is not sufficient at present.

In this way, in the production of conventional fibers for reinforcing rubber structures, it is possible to improve only some of the various required properties, but the negative factors associated with this also appear, and it is a contradictory character. there were.

Therefore, the inventor of the present invention has conducted intensive studies to provide a polynisdel fiber that has a high intrinsic viscosity [η], maintains high strength, has high model elongation, low shrinkage, and has excellent durability in rubber. It is possible to reduce the orientation of the amorphous part of the amorphous part, increase the density of the amorphous part and the number of tie molecules, make the bond between the crystal part and the amorphous part dense, and keep the unlaked carboxyl content below a certain range. They found a good solution and arrived at the present invention.

That is, the present invention provides a polyester fiber having ethylene terephthalate as a main constituent unit, having a terminal carboxyl group weight of 10 equivalents/10·g polymer or less, an amorphous orientation fa of 0.55 to 0.64, and a long fiber. □''This is a book related to polynisder fibers with a periodic distance of 130 to 160A, which are highly strong and have excellent thermal stability.

In the present invention, the polyester mainly refers to polyethylene terephthalate consisting of a prephthalic acid component and an ethylene glycol component, but a polyester in which a part of the terephthalic acid component, usually 10 or less, is replaced with another dicarboxylic acid component. and/or ethylene IJ
It may also be a polyester in which a portion of the coal component, usually less than 10 molar capsules, is replaced with another diol component. Also,
For example, modifiers, stabilizers, etc. may optionally be used in such polynisdels, as required.

The degree of polymerization of the fiber of the present invention made of such polyester is
In order to provide sufficient strength in the final rubber structure, r
0.8θ or more, especially #'i0.
The range of 83 to 0.95 is preferable.

In this example, the d5 intrinsic viscosity was determined using an orthochlorophenol solution at 35°C.

The polyester fiber of the present invention has a terminal carboxyl group weight of 10 equivalents/10·g polymer or less, 0.55 to 0.
Both the degree of amorphous orientation of 64 A and the long period interval of 130 to 160 A must be satisfied.

That is, when the amount of terminal carboxyl groups is more than 10 equivalents/106 grams of polymer, the degree of amorphous orientation and long period interval are suitable, and the objective of the present invention is to achieve high strength, high modulus, low shrinkage, and medium durability of the rubber. Polyester fibers do not satisfy the physical properties and sound characteristics. Further, if the degree of amorphous orientation does not reach 0.55, the above properties, especially strength and modulus, are non-light components, and if the degree of amorphous orientation is higher than 0.64, the optical partial pressure will not be particularly low in shrinkage ratio. When the long period interval is outside the range of 130 to 160 A, all of the above characteristics cannot be satisfied even if the other requirements are sufficiently small, that is, the number of terminal carboxyl radicals is sufficiently small and the degree of amorphous orientation is at an optimum value.

It satisfies all of the terminal carboxyl group content, amorphous orientation degree, and long period interval, and has high strength, high modulus, low shrinkage, and excellent durability in rubber, which could not be obtained conventionally.
Furthermore, the polyester fiber of the present invention has a history of low heat generation in rubber and extremely excellent fatigue resistance.
When the dry heat shrinkage rate at °C is 9.0 to 1 slH, the heat setting properties are good during the subsequent high-temperature processing of the 4th processing for rubber reinforcing materials, and at the same time, they are easily good without sacrificing mechanical properties. This is extremely preferable since it provides excellent thermal stability. When this dry heat shrinkage rate is as low as 9%□□, the decrease in shrinkage rate during heat treatment during post-processing is relatively small. Moreover, if it is higher than tS, it is difficult to achieve a low shrinkage rate even by heat treatment during post-processing, and the strength and durability are likely to decrease due to this heat treatment.

The polyester fiber of the present invention can be obtained by the following method, namely, terminal carboxyl group weight: 10 equivalents/1
A polyester having a specific stacking capacity of 0.04 grams or less and a specific density of 0.85 or more, preferably 0.87 to 1.10 is spun in a molten state into a cooling zone and immediately quenched and solidified, with a take-up rate of 100011 L/min or more, preferably Fitsoo ~ s
Birefringence of 2000 ~ by taking off at ooom/min
7000X10, preferably 3000-7000X
10-5, II! preferably 4000 to 5000
It is produced by obtaining an undrawn yarn of 10-5 and stretching the undrawn yarn at a breaking elongation of 80 or more, preferably 82 or more. This stretching may be carried out continuously following spinning, or it may be carried out once after spinning and then stretched. When carrying out continuous spinning subsequent to spinning, ]1゜First, a single-stage drawn yarn with a birefringence of 0.16 or less with meridian reflection (001) present in the X@ wide-angle diffraction pattern is prepared, and then multi-stage drawing heat treatment is performed. This method is useful.

In addition, when drawing after spinning, it is useful to carry out multi-stage stretching heat treatment after the first stage stretching is set to 75 or less of the total stretching ratio so that the increment in birefringence is 4 times or less. . In any case, during these stretching steps (in the first stage of stretching when multistage stretching is performed), 250
It is preferable to employ a steam gradient method in which heated steam of 80 to 120° C. is jetted out, preferably 280 to 600° C., or a heated roller method of 80 to 120° C. In addition, the dry heat shrinkage rate at 175°C of the fiber obtained by heat treatment after stretching was 9
It is desirable to set it in the range of ~15-. This shrinkage rate is achieved by bringing the drawn yarn to a temperature of (melting point -50°C) to (melting point -110°C) and holding it for 0.4 to 1.5 seconds under a tension of 2.5 to 15 degrees. .

Various methods can be employed to reduce the amount of terminal carboxyl groups to 10 equivalents/106 grams of polymer or less.
It is d. For example, (1) a method in which phenyl glycidyl ether is refluxed into a molten polyester as disclosed in Japanese Patent Publication No. 44-27911; (2) a method in which linear polyester carbonate is added to a molten polyester as in Japanese Patent Publication No. 45-41235; (3) A method of reacting polyester with ethylene oxide, as disclosed in Japanese Patent Publication No. 47-12891. (4) A method of reacting polyester with glycol ester of oxalic acid or oxalic acid polyester, as disclosed in Japanese Patent Publication No. 48-35953. Method of making (5)% 54g-4
Method (6) of reacting polyester Kll-like carbonates as in Publication No. t7xa (6) Method of reacting polynisder with diaryl oxalates and/or diarylmalonates and diaryl carbonates as in Publication No. 49-5233 (7) ) Method of reacting carbodiimide with polyester as in U.S. Pat. No. 3,193,522+8) Method of reacting with bis-cyclic imino ether as in Special Publication No. 4734/1983 Depending on the desired intrinsic viscosity and amount of terminal carboxyl groups It is OT m that can be adopted from time to time. A preferred method is to avoid coloring of the resulting fibers, to avoid foaming due to decomposition of additives during spinning, and to reduce the amount of terminal carboxyl groups to 10 equivalents/10-gram polymer or less without reducing the degree of polymerization. It is.

The polyester fiber of the present invention thus obtained is made into a cord according to a conventional method, coated with an adhesive, heat treated, and then applied to the rubber structure.

In this case, the heat treatment temperature and degree of elongation are preferably set to -1 so that the maximum heat shrinkage stress of the polyester fiber before treatment is 55 or less. Specifically, heat treatment after cording was carried out at 200-260°C under elongation up to 20°C! ! ”
It is preferable to carry out a heat treatment for 30 to 240 seconds at a temperature of 100°C.

By performing such heat treatment, the best performance can be exhibited, as will be clear from the following examples. That is, the heat-treated cord for rubber reinforcement obtained from the polyester fiber of the present invention has a strength of 6 f/dB or more and a temperature of 175°C.
The dry heat shrinkage rate is 4.5% or less, and the elongation at 4.5 Kf load is 4.5- or less, which is high degree, low shrinkage, and high modulus. In addition, the heat generation temperature in the rubber structure obtained by disposing and vulcanizing in rubber is lower than that of cords obtained from conventional rubber reinforcing polyester fibers, and fatigue resistance is significantly improved. Therefore, the degree of strength deterioration in the rubber structure is small and the durability is excellent.

The rubber structure referred to in the present invention is, for example, a tire.

V-belt, conveyor belt natural comb.

Refers to all structures made of synthetic rubber, etc.

The present invention will be further explained with reference to Examples below.

Incidentally, the measured values of the six tanks in the examples are based on the following method.
′□ (1) The amount of terminal carboxyl group is determined by Nie-Conics (
A, coniz) method (Makr・)mol, (!
hem, 2 a.

226.1958).

(2) The degree of amorphous orientation fa is determined by the method described in the paper by Robert J. Saminil (J, Polymer 5science).
Calculated using A 2 , 10 , 781 , 1972+.

That is, Δn −XfcΔnc + (1−X)faΔn
a Here, Δn is a parameter indicating the degree of orientation of molecules in the filament, and was determined by the retardation method using Promnaphthalene as the immersion liquid and a Berenck compensator. For a detailed explanation, please refer to "Kyoritsu Shuppan F Polymer Experimental Course/Physical Properties of Polymers U".

fc is the degree of crystal orientation and was determined by a conventional method from the pruritus angle X and the average orientation angle α measured by @diffraction.

X is the degree of crystallinity, which was determined from the density using a conventional method.

ΔnC and Δna are crystalline and amorphous intrinsic birefringence, which are 0.220 and 0.275 for polyethylene terephthalate, respectively.
It is.

(3) The long-period interval can be determined using a conventionally known method using a small-angle X-ray scattering measurement device, that is, by using CuKa- with a wavelength of 1.54 A as a radiation source and irradiating it at right angles to the fiber axis. It was calculated from the diffraction line using Bragg's formula.

(4) Load-stretching curve is JISL 1017-19
63(5,4)K compliant.

(5) Dry heat 175℃ shrinkage rate is JISL11017-
Based on 1963 (5, 12).

(6) Tube heat generation temperature and tube life are JIS
・L1017-1963.1.3.2. Compliant with IA law.

However, the bending angle was 90°. The exothermic temperature is 9 at the start of operation.
After 0 minutes, the temperature of the tube surface was measured using an infrared non-contact thermometer (SA
(manufactured by W-E1), and the tube life was expressed as the time until tube breakage.

(7) For heat resistance and strength, R
It was immersed in FL adhesive solution and heat-treated at 245° C. for 3 minutes under tension. Embed this processing code into the vulcanization mold 170
After accelerated vulcanization for 120 minutes at a temperature of 5 degrees Celsius and a pressure of 5 degrees Kr/ffl, the treated cord was taken out and its tenacity was measured.

[Example 1] 97'' parts of dimethylnaphthalate (parts indicate parts by weight,
The same shall apply hereinafter), 69 parts of ethylene glycol, 0.034 parts of calcium acetate monohydrate, and 0 parts of antimony dioxide.
．． After charging 0.025 parts into an odocrape and removing methanol produced as a result of tennis chill exchange at 180-230°C while slowly passing nitrogen, 0.05 parts of a 50% aqueous solution of H*POa was added and the heating temperature was increased to 28 QC. After increasing the temperature, 0.025 part of potassium iodide was added and the pressure was gradually reduced to 0.2 IollIg1c in about 1 hour, and the polymerization reaction was continued for 2 hours. As a result, a polymer having an intrinsic viscosity of 0.90 and a terminal carboxyl group content of 32.2 equivalents/lo' Durham polymer was obtained.

Here, the reaction system was brought to normal pressure with nitrogen gas, 1,2-di7-functional ethylene oxide was added in the amount listed in Table 1, and the reaction was carried out at normal pressure for 10 minutes, and then the reaction was carried out again. The pressure of the system was set to 0.2. , &1gK, and the polymerization reaction was continued for 30 minutes.

The intrinsic viscosity and the amount of terminal carboxyl groups of the obtained polymers were as shown in Table 1 depending on the amount added.

Table 1 Next, using the above two types of polyester polymers*, Bt,
Various drawn yarns were obtained by spinning and drawing.

That is, the above polyester polymer is melted at about 290°C,
After being discharged from a spinneret having a hole diameter of 0.551a1 and a number of holes of 25041, the discharged yarn is immediately exposed to cooling air t-3 at 25°C.
ONi1l''/Maro It was cooled and solidified while being sprayed, and then the oil was applied with an oiling roller and rolled up at the speed shown in Table 2. The properties of this undrawn yarn are shown in Table 2. The drawn yarn is supplied to a roll heated to 85°C, and after one-stage drawing with a take-up roll at the ratio (DR,) shown in Table 2, it is passed through a gas bath heated to 325°C 2nd stage stretching was carried out at a magnification (DRI) of
It was subjected to tension heat treatment at a ratio of 1 (DRs) without using any parts. Table 2 shows the physical properties of the polymer string and the obtained drawn yarn.

Next, these drawn yarns were given 2 twists of 490 times/wL, and then "total of these two yarns were given 8 twists of 490 times/S, and 10
The raw cords, which were made into two 00deX raw cords, were immersed in adhesive liquid (RFL liquid) K and subjected to tension heat treatment at 245°C for 3 minutes. The characteristics of this treated cord, as well as the tube fatigue resistance and heat resistance strength after vulcanization with Kal injected into the rubber, were measured. The results are also listed in Table 2.

[Example 2] 97 parts of dimethyl terephthalate, 6 parts of ethylene glycol
Part 9, calcium acetate! Parts of aqueous salts o, osa and 0.044 parts of antimony dioxide were heated to 160 to 230°C while the generated methanol was distilled out of the system. After that, the pass temperature was gradually raised to 275℃ and the eel was heated under normal pressure for 30 minutes.
．． The polycondensation reaction was continued for 60 minutes under a reduced pressure of 151,111 inches. Here, the reaction system was returned to normal pressure using nitrogen gas. The intrinsic viscosity of the obtained polymer was 0.58.

Here, 1.21 parts of diphenyl oxalate (1.0 molar relative to terephthalic acid) and 1.07 parts of diphenyl carbonate (based on terephthalic acid).

After the reaction was carried out under normal pressure for 10 minutes, the pressure was gradually reduced and the polymerization reaction was again continued for 20 minutes under reduced pressure of 0.2 + 1 g or less. The obtained polyester had an intrinsic viscosity of 1.10 and a terminal carboxyl group content of 2.
7 equivalents/lO'fr polymer.

This polynisder polymer was melted at about 300°C and the pore size was 0.
．． 55 parts 1 m 1 hole fi 250 +! Immediately after the yarn is discharged from the spinneret having the temperature i, 2 parts of cooling air at 5° C. is applied to the discharged yarn.
(L Nm”/sj) Cooling is carried out while spraying,
After that, apply oil with an oiling roller to 2200
The yarn is guided to a take-up roller that rotates at a speed of yi/min, and without being wound up, the yarn is immediately drawn at a threshold of 1.5 times by spraying a steam jet of 2.24 parts mG at an angle of 45° onto the yarn. did.

At this time, the intrinsic viscosity of the thread that reached the take-up roller was 0.95.
, a terminal carboxyl group weight of 6.2/106 tr polymer, and a birefringence of 4540 X 1 G-5. Further, the yarn drawn in one step to 1.5 times showed clear meridian reflection (OOl) intensity in the X1li wide-angle diffraction pattern, and the birefringence was o, tss. Next, this one-stage drawn yarn was stretched to 1.53 times through a heating bath at 325°C, and then stretched to 360°C.
Heat treatment was carried out through a heating bath at 1.05 °C. The performance of the obtained stretching heat treatment system was as follows.

Fineness: 1015 de, strong [: 9.8 f/de].

Elongation: 8.2 *, non-uniorientation degree: 0.64.

Long cycle: 152λ, 175℃ Dry yield: 12.3%.

Next, this drawn yarn was made into a treated cord in the same manner as in [Example 1]. The physical properties of the obtained cord are as follows.

Strong crab 16.14, 4.5 Kf load: 3.5%.

175℃ dry yield: 3.44k, tube life: 503
[Example 3] 97 parts of dimethyl terephthalate (parts indicate parts by weight, the same applies hereinafter), 69 parts of ethylene glycol, 0.034 parts of calcium acetate monohydrate, and trioxide. antimony 0.0
After charging 25 parts into an odocrape and removing methanol produced as a result of transesterification at 180 to 230°C while slowly passing nitrogen, add 50 parts of an aqueous solution of HsPOa to 280°C and raise the heating temperature to 280°C. At the same time, the pressure of the reaction system is gradually reduced to 0, 2. , HgK and continued the polymerization reaction for 1 hour and 20 minutes to obtain a polymer having an intrinsic viscosity of 0.75 and a terminal carboxyl group weight of 35 equivalents/1 o"tr polymer.

100 parts of this polymer chip was triblended with o, os, 0.15, and 0.22 parts of 2,2'-bis(2-oxazoline), and then melted at about 295°C to obtain a pore size of 0.
After being discharged from a spinneret having 6 + 111 + 250 holes, the discharged yarn is immediately blown with 25°C cooling air at 4° ON 11l'
The yarn was cooled and solidified while being sprayed for 2500 WL/min, and then an oil agent was applied using an oiling roller, and the yarn was guided to a take-up roller rotating at 2,500 WL/min and wound up as an undrawn yarn.

Next, this undrawn yarn was supplied to a roll heated to 90°C, and stretched in the first stage to 1.5 g by 4 times with a take-up roll, and then stretched to 1.421 times through a 330C gas bath. Second
After stage stretching, it was heat-treated at a tension ratio of 1.05 through a 150C heated roll and a 300C gas bath.

Next, this drawn yarn was pressed into a treated cord in the same manner as in [Example 1], and the obtained 2,2'-bis(2-oxazoline)
Table 3 shows the properties of the undrawn yarn, drawn yarn, and treated cord when the amount of addition was changed.

Table 3 Patent applicant Teijin Ltd.

Claims (3)

[Claims] (1) A polyester fiber mainly composed of ethylene terephthalate, with a terminal carboxyl group weight of 10 equivalents of 710°g polymer or less, and a high-strength polyester fiber with non-le orientation [fa and long-period spacing that satisfies the following: Polyester*am with excellent thermal stability. fa -0,551A-0,64 L ÷130~160A (2) The polyester fiber according to item 1, which has a dry heat shrinkage rate of e, o to 15 at 175°C. (3) Is the intrinsic viscosity 0.80 or more? 1ffl
Polyester fiber 1 according to item 1 or item 2 of the desired range