JPH0440449B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a high-strength, high-elasticity polycapramide fiber and a method for producing the same. In particular, the present invention relates to a high-strength, high-elasticity polycapramide fiber and a method for producing the same. In particular, the present invention relates to a polycapramide fiber with high strength retention after vulcanization and excellent uniformity when made into a tire cord. The present invention relates to a polycapramide fiber and a method for manufacturing the same with high efficiency. [Prior Art] Polyamide fibers have high strength and excellent fatigue resistance and impact resistance, so they are used in various industrial applications, such as tire cords, rubber reinforcing cords for conveyor belts, seat belts, sewing threads, etc. Used for fishing nets, various cover sheets, etc. However, polycapramide fibers lack dimensional stability, have a low initial modulus, and in particular have a significant reduction in reinforcement after rubber vulcanization, which limits their use. Therefore, a number of proposals have been made to overcome these drawbacks. For example, JP-A-57-
As seen in Publication No. 191337, the spinning speed was set to 2000.
After high-speed spinning at ~4500 m/min and stretching the resulting undrawn yarn at at least 85% of the maximum magnification,
A method of using nylon 6 cord for rubber reinforcement has been proposed. By this method, polycapramide fibers with improved dimensional stability and reduced tenacity during vulcanization have been obtained. Furthermore, as in Japanese Patent Application Laid-Open No. 59-144608, a method has been proposed in which the spinning speed is set to less than 2000 m/min, followed by continuous stretching and winding at a speed of 4000 m/min or less. Furthermore, Japanese Patent Application Laid-Open No. 58-54018 proposed a polycapramide fiber with a low shrinkage rate and excellent fatigue resistance, and a method for producing the same. This publication very generally teaches a direct spinning/drawing method in which nylon 6 is spun at high speed and then directly drawn. [Problems to be solved by the invention] Although the method disclosed in JP-A-57-191337 improves the strength after vulcanization, the fiber strength is at most 8.5 g/d, which is lower than that of conventional industrial fibers. It was only of a low level compared to commercial fibers. If the number of filaments exceeds 150fil, such as yarn for rubber reinforcement, simply increasing the spinning speed will cause filament unevenness due to inter-yarn interference due to cooling of the yarn, which will likely cause drawn yarn breakage, resulting in high This is because strong fibers cannot be obtained. Furthermore, although highly durable fibers can be obtained by the method disclosed in JP-A-59-144608, the cord strength after rubber vulcanization is by no means high.
Furthermore, the yarn strength of the fiber was at most 9.4 g/d, which was at a lower level than that of conventional industrial fibers. Although the polycapramide fiber already proposed in JP-A No. 58-54018 has a low shrinkage rate and excellent fatigue resistance, the strength level of the raw yarn is still only 9.1g/
It was only at a low level, about d. In other words, the object of the present invention is to suppress the decrease in strength after rapid temperature changes such as during rubber vulcanization, which is caused by the occurrence of structural defects in nylon 6 fibers, and to have excellent dimensional stability as a fiber. The object of the present invention is to provide an unprecedented high-strength nylon 6 fiber that not only has properties useful as an industrial fiber such as excellent fatigue resistance, but also has high uniformity. [Means for Solving the Problems] As a result of intensive studies, the present inventor has arrived at the following invention. That is, (1) consisting of an ε-capramide polymer with repeating structural units of 95 mol% or more, having a high degree of polymerization with a sulfuric acid relative viscosity of 3.0 or more, and containing one or more copper salts and/or the copper A polycapramide fiber containing an inorganic or organic antioxidant other than salt, which also has the following properties. Tm≧188 (°C) fc≧0.93 0.83≧≧0.7 2≧γ≧0.3 (%) Here, Tm is after treating the fiber with acetylene, freezing the amorphous part by γ-ray irradiation, and then using DSC. melting point measured by fc is the degree of crystal orientation measured by X-rays. is the degree of amorphous orientation measured by fluorescence polarization method. γ is the percentage of γ-type crystals measured by X-rays. (2) The polycapramide fiber according to item 1 above, characterized in that strength T/D, elongation E, and initial tensile resistance Mi satisfy the following formula at the same time. T/D≧10 (g/d) 18≧E≧10 (%) Mi≧25 (g/d) (3) Dry yield (ΔS) at 150℃ is in the range of 6≧ΔS≧3 (%) The polycapramide fiber according to item 1 above, characterized in that the polycapramide fiber has a value of: (4) The polycapramide fiber according to item 1 above, wherein the density ρ is in the range of ρ≧1.145 (g/cc). (5) The polycapramide fiber according to item 1 above, wherein the birefringence Δn is in the range of Δn≧0.057. (6) Consisting of an ε-capramide polymer with repeating structural units of 95 mol% or more, having a high degree of polymerization with a sulfuric acid relative viscosity of 3.0 or more, and one or more copper salts and/or other than the above-mentioned copper salts When performing a direct spinning/drawing method in which a polycapramide-based polymer containing an inorganic or organic antioxidant is melt-spun and wound at a speed of 5,000 m/min or more, the melt-spun yarn is placed in an atmosphere of at least 10 cm below the spinneret. After passing through a zone surrounded by a cylinder heated to a temperature above (melting point + 30℃), it is rapidly cooled, and then a non-aqueous oil is applied under a tension that satisfies the following formula, and at a speed of 2000 m/min or above. 1. A method for producing polycapramide fibers having the properties expressed by the following formulas, the method comprising taking off and subsequently carrying out two or more stages of hot stretching while satisfying the formulas below. 5≧T/(n×V ^1.4 ×d ^0.2 ×10 ^-5 ≧1 …… 0.17≧ (ηr ₁ − ηr ₂ )/ηr ₁ ≧0.05 … Here, T is the spinning tension during oiling (g weight) , n is the number of filaments of the fiber, V is the take-up roll speed (m/min), d is the single yarn fineness (denier) at the time of oiling,
ηr ₁ is the relative viscosity of sulfuric acid on the yarn on the take-up roll, ηr ₂
indicates the relative viscosity of sulfuric acid of the yarn after final winding. Tm≧188 (℃) ... fc≧0.93 ... 0.83≧≧0.7 ... 2≧γ≧0.3 (%) ... Here, Tm is γ after the fiber is treated with acetylene.
The amorphous part is cross-linked and frozen by radiation irradiation, and then
Melting point determined by DSC. fc is the degree of crystal orientation measured by X-rays. is the degree of amorphous orientation measured by fluorescence polarization method. γ is the percentage of γ-type crystals measured by X-rays. [Function] In the polycapramide polymer used in the present invention, 95 mol% or more of repeating structural units in the molecular chain are ε-capramide, and the polycapramide polymer may contain less than 5 mol% of a copolymer component. Examples of the copolymerization component include polyhexamethylene adipamide, polyhexamethylene sebacamide, polyhexamethylene isophthalamide, polyhexamethylene terephthalamide, and polyxylylene phthalamide. If the copolymerization component is contained in an amount of 5 mol % or more, crystallinity and dimensional stability are reduced, which is not preferable. The polycapramide polymer must have a sulfuric acid relative viscosity of 3.0 or more when measured using an Ostwald viscometer at 25°C and a polymer concentration of 1% by weight.
Furthermore, a polymer with a high degree of polymerization of 3.2 or more is preferred.
If this value is less than 3.0, the molecular chains of the fiber will be too short and the desired high strength fiber will not be obtained. Furthermore, it is necessary to add an antioxidant to the polymer in order to provide sufficient durability against heat, light, oxygen, etc. Without this additive, deterioration due to heat, light, oxygen, etc. will proceed during spinning and high-order processing steps, resulting in a significant decrease in durability. Antioxidants include copper salts such as copper acetate, cuprous chloride, cupric chloride, cuprous bromide, cupric bromide, cuprous iodide, copper phthalate, copper stearate, and various others. Complex salts of copper salts and organic compounds, such as 8-oxyquinoline copper, 2
- Copper complex salts of mercaptobenzimidazole, preferably cuprous iodide, copper acetate, cuprous iodide complex salts of 2-mercaptobenzimidazole, etc., halides of alkali or alkaline earth metals, such as potassium iodide, bromide, etc. Potassium, potassium chloride, sodium iodide, sodium bromide, zinc chloride, calcium chloride, etc., organic halides such as pentaiodobenzene, hexabromobenzene, tetraiodoterephthalic acid, methylene iodide, tributylethylammonium iodide, etc. , inorganic and organic phosphorus compounds such as sodium pyrophosphate, sodium phosphite, triphenylphosphite, 9,10-
Dihydro-10-(3',5'-di-t-butyl-4'-
hydroxybenzyl)-9-oxerperfluorophenanthrene-10-oxide, etc., and phenolic antioxidants, such as tetrakis-[methylene-3-(3,5-di-t-butyl-4-hydroxyphenyl) )-propionate]-methane,
1,3,5-tri-methyl-2,4,6,-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene, n-octadecyl-3-(3,
5-di-t-butyl-4-hydroxyphenyl)
-propionate, 4-hydroxy-3,5-di-t-butylbenzyl phosphate diethyl ester, etc., and amine antioxidants, such as N,N'-di-β
-naphthyl-p-phenylenediamine, 2-mercaptobenzimidazole, phenyl-β-naphthylamine, N,N'-diphenyl-p-phenylenediamine, condensation reaction product of diphenylamine and allyl ketone, preferably potassium iodide, 2 −
Examples include mercaptobenzimidazole. The antioxidant can be mixed into the chips during the polymerization process of polycapramide or after the chips are formed. Its content is 10 to 300 ppm as copper in copper salts, preferably 30 to 150 ppm, and 0.01 to 1%, preferably 0.03 to 0.5% in other antioxidants.
is within the range of If this value is less than 10 ppm as copper or 0.01% as other antioxidants, the heat resistance, light resistance, and weather resistance of the fiber will decrease. Also, this value is 300ppm
Alternatively, if it exceeds 1%, the strength of the fibers decreases due to loss of uniformity. In the present invention, after the fiber is treated with acetylene, the amorphous part is cross-linked and frozen by γ-ray irradiation.
The melting point measured by DSC must be 188°C or higher. Furthermore, the temperature is preferably 190°C or higher. This value is considered to be the original melting point of the fiber, and a high value is considered to indicate high crystal integrity. If the crystal integrity is high, there will be little structural change in response to thermal stimulation such as during the vulcanization process, and the strength retention rate after thermal stimulation compared to before thermal stimulation will be higher. Also, this value
If the temperature is lower than 188°C, the crystal integrity is low and the strength retention of the fiber is reduced. Further, the degree of crystal orientation fc needs to be 0.93 or more. This high degree of crystal orientation is a necessary condition for obtaining high strength fibers. When this value is less than 0.93, the crystal orientation is low and the strength of the fiber is reduced. Next, the degree of amorphous orientation must be between 0.7 and 0.83. If this value is less than 0.7, the orientation of Taimolekyur is poor and high strength fibers cannot be obtained.
Fatigue resistance also decreases. Moreover, when this value exceeds 0.83, the shrinkage of the fiber becomes large and the dimensional stability deteriorates. Furthermore, the γ-type crystal content ratio (γ) needs to be 0.3 to 2%. If this value is less than 0.3%, the uniformity of the fibers decreases, which is not preferable. Also, this value is 2
If it exceeds %, crystal stability will be low, structural changes will be large in response to thermal stimuli such as vulcanization process, and strength retention will be low. The polycapramide fiber according to the present invention is obtained by a special and novel method as described below. In summary, the method involves passing the spun yarn through a zone surrounded by a cylinder heated to a temperature higher than the melting point of polycapramide (+30°C), then rapidly cooling and solidifying it.
Next, a non-aqueous oil agent is applied under a specific spinning tension,
In direct spinning and drawing, it is important to perform multi-stage hot drawing and winding at high speed while the relative sulfuric acid viscosity of the yarn on the take-up roll and the relative sulfuric acid viscosity of the yarn after final winding satisfy a specific formula. shall be. The details of the spinning process will be explained based on FIG. 1 (a process diagram showing one embodiment of the present invention). After passing the yarn Y spun from the spinneret 1 through a zone surrounded by a cylinder 2 in which the atmosphere of at least 10 cm below the spinneret is heated to a temperature higher than the melting point of the polycapramide, it is rapidly cooled and solidified in a cooling device 3, and then oiled. A non-aqueous oil agent is applied by a device 4, and taken up by a take-up roller 5 that rotates at a speed of 2000 m/min or more. Next, the film is subjected to multi-stage hot drawing by rotating around heated drawing rolls 6, 7, and 8, and is relaxed by a relaxing roll 9 at a speed of 5500 m/min or more and wound up on a winding machine 10. The important point here is to supply oil, take-off, and direct spinning/drawing while satisfying the following formula at the same time. 5 ^≧ T/ ₍ n _{× V} ^1.4 × ^d 0.2 ), n is the number of filaments of the fiber, V is the take-up roll speed (m/min), d is the single yarn fineness (denier) at the time of oiling,
ηr ₁ is the relative viscosity of sulfuric acid on the yarn on the take-up roll, ηr ₂
indicates the relative viscosity of sulfuric acid of the yarn after final winding. It will be explained in further detail. When the yarn Y spun from the spinneret 1 passes through a zone surrounded by a cylinder 2 in which the atmosphere at least 10 cm below the spinneret is heated to a temperature higher than the melting point of the polycapramide (+30°C), the temperature at the bottom surface of the spinneret increases. is 270
The temperature should be ~320°C, preferably 280-310°C. If the temperature is below 270°C, the viscosity of the polymer is too high, resulting in uneven polymer flow and even thread unevenness, making it impossible to obtain the high-strength yarn that is the object of the present invention. Moreover, at temperatures above 320°C, polymer bending and dripping phenomena occur on the spinneret surface, resulting in poor yarn-spinning properties. In addition, it is important to control the ambient temperature directly below the cap to a temperature higher than the melting point of the polycapramide (+30° C.) in order to maintain the uniformity of the thread. That is, by maintaining the atmosphere at least 10 cm below the die at a temperature higher than the melting point of the polycapramide, uneven molecular orientation between the multifilaments can be eliminated and uniformity in subsequent stretching can be improved. In order to control the ambient temperature directly under the cap to a temperature higher than the melting point of the polycapramide, it is necessary not only to heat only the exposed cap surface, but also to provide a heated cylinder of at least 10 cm directly below the cap. Temperature: 250℃ or higher, preferably 270~
The temperature shall be 350℃. If the length of the zone is less than 10 cm and its temperature is less than 250°C, the uniformity of the yarn will be poor and the purpose of the invention cannot be achieved. The type of the cooling device 3 includes a uniflow type, an annular natural suction type, an annular suction type, etc., but is not particularly limited. The oil supply device 4 may be of a roll type, a guide type, etc., but the guide oil supply type is preferable because it can uniformly apply the lubricant and has less contact resistance. Further, as the oil agent, it is necessary to apply a non-aqueous oil agent that can suppress moisture absorption crystallization, which is one of the causes of non-uniformity during stretching. If a water-based oil agent is applied, the uniformity will be impaired and the desired high-strength fiber will not be obtained. The tension at the time of refueling (Tg weight) is n×V ^1.4 ×d ^0.2 ×
It needs to be 10 ^-5 to 5 x n x V ^1.4 x d ^0.2 x 10 ^-5 . [Here, n is the number of filaments of the fiber, V is the take-up roll speed (m/min), and d is the single yarn fineness (denier) at the time of oiling] This value is n x V ^1.4 x d ^0.2 x
When it is less than 10 ^-5 , cooling spots occur in the yarn, resulting in a decrease in strength. If this value exceeds 5×n×V ^1.4 ×d ^0.2 ×10 ⁻⁵ , scratches and air resistance spots occur, and the strength also decreases. The tension at the time of oiling can be adjusted by changing the vertical distance from the mouth surface of the oiling device, adjusting the angle of contact with the guide, adjusting the viscous resistance of the applied oil, and adjusting the focusing of the multifilament. There are various methods such as controlling the state using guides, cooling air, etc. As the take-up roll 5, a pair of Nelson rolls with a satin-finish surface may be made to make many turns, or a single mirror-surfaced roll may be made to make half a turn. The temperature of this take-up roll is usually below 120℃
It may be heated at a temperature of 90°C or less, or it may be left at room temperature without heating. The stretching method uses a direct spinning/drawing method in which the film is taken up by a take-up roll 5 and then subjected to multistage hot stretching. After the yarn is taken off, it is not stored in an undrawn state where the fiber structure is likely to change due to moisture absorption, so the yarn has high uniformity and high strength fibers can be obtained. The total stretching ratio is 3 times or less, and the film is stretched in multiple stages.
Make sure that the relative sulfuric acid viscosity of the yarn on the take-up roll ηr ₁ and the relative sulfuric acid viscosity of the yarn after final winding ηr ₂ satisfy the formula 0.17≧(ηr ₁ −ηr ₂ )/ηr ₁ ≧0.05. There is a need. When (ηr ₁ −ηr ₂ )/ηr ₁ is less than 0.05, stretching is insufficient and high strength cannot be obtained. Also (ηr ₁
-ηr ₂ )/ηr ₁ exceeds 0.17, there will be too much molecular chain scission and high strength will not be achieved. An example of the stretching method of the present invention will be described. 1DR (first draw roll) 6 is 80-180℃,
2DR (second draw roll) 7 is 150-210℃, 3DR
(Third draw roll) 8 is set at a temperature below the melting point of the polycapramide, usually 150 to 210°C, and the temperature of each roll must be the same as or higher than the temperature of the preceding roll. The temperature of the last placed RR (tension adjustment roll) 9 is 210°C or less. The yarn is 1.1~ between take-up roll 5 and 1DR6
2.0x, 1.1 to 2.0x between 1DR6 and 2DR7, 2DR
Stretched at 1.1 to 2.0 times between 7 and 3DR8, 3DR
Between 8 and RR9, it is contracted in the range of 0.9 to 1.0. Note that a device for injecting a jet flow of air or steam may be provided between the rolls to fix the drawing point of the yarn. Particularly preferred is a take-up roll between 5 and 1DR6 and between 1DR and 2DR7, which have a high magnification. [Example] Next, an explanation will be given based on an example. The method for measuring the characteristics of the present invention is as follows. Cross-linking freezing method melting point Tm: Put the polycapramide fiber in a glass container,
After creating a vacuum of approximately 10 ^-2 mmHg, the chamber is filled with acetylene gas at approximately 600 mmHg and irradiated with gamma rays at room temperature. The source was ⁶⁰ Co, the dose was 5 x ¹⁰⁴ rad/hr, and the total dose was 0 to 20 Mrad. Since the amorphous portion of the treated fiber is cross-linked and frozen, it is possible to measure the melting point of imperfect crystals unique to the sample. Its melting point is
Measurement was performed using DSC-IB model manufactured by Perkin-Elmer.
The sample conditions were a heating rate of 10°C/min, a sample amount of 4.0mg,
The experiment was carried out at a full scale sensitivity of 4 mcal/sec. (10 o'clock, Kawaguchi, Heat Measurement, 12(1), 2-20,
1985) Crystal orientation fc: Measured using a wide-angle X-ray scattering device D-3F model manufactured by Rigaku Denki Co., Ltd. using CuKα as a radiation source. Half-width of the intensity distribution curve along the Debye ring of (200) equatorial interference, where the orientation function of the crystal part is fc
Calculated from H° using the following formula. fc=(180°−H°)/180° Degree of amorphous orientation: The sample was coated with fluorescent agent “Whitex RP” [Sumitomo Chemical Co., Ltd.]
2 hours at 20℃ in a 0.2% aqueous solution of
Next, it was thoroughly washed and air-dried to prepare a measurement sample.
The relative intensity of polarized fluorescence was measured using a FOM-1 polarization photometer manufactured by JASCO Corporation, and was determined by the following formula. =1-B/A However, A: Relative intensity of polarized fluorescence in the direction of the fiber axis B: Relative intensity in the direction perpendicular to the fiber axis γ-type crystal mixture ratio γ: Wide-angle X-ray scattering device D-3F manufactured by Rigaku Denki Co., Ltd. Measurements were made using CuKα as a radiation source using a mold. Using a fiber bundle of 8 cm length, 40 mg, and 1 mm width as a sample, fix the sample and measure the meridian (020) interference peak intensity at a scan speed of 1°/min. 2θ=9°~14°
Connect them with a straight line to find their integrated strength, and set α in advance.
Calculated from a calibration curve created using the weight mixing ratio of the type standard sample and the γ type standard sample. For the α-type standard sample, the sample of Comparative Example 1 was fixed in a mold under a tension of 1/20 g/d, and then placed in a steam pot at 155°C.
Processed for 15 minutes. The γ type standard sample is Comparative Example 1
The sample was immersed in an iodine-potassium iodide solution (508 g of iodine, 66.4 g of potassium iodide/400 ml of distilled water) for 70 hours to adsorb iodine, and then deiodized with a sodium thiosulfate solution. Tensile strength T/D, residual elongation E, initial tensile resistance Mi: As defined by JIS-L1017. Take the sample in a skein shape, leave it in a temperature-controlled room at 20°C and 65% RH for 24 hours, and then test it using a "Tensilon" UTM-4L tensile tester [manufactured by Toyo Baldwin Co., Ltd.] at a test length of 25 cm and a tensile speed of 30.
It was measured by drawing a load-extension curve in cm/min. Dry heat shrinkage rate ΔS: Take the sample in a skein shape and store it in a temperature-controlled room at 20℃ and 65%RH.
After being left for more than 24 hours, a sample of length l ₀ was measured by applying a load equivalent to 0.1 g/d of the sample. After being left in an oven at 150°C under no tension, the sample was taken out from the oven and It was left in a temperature-controlled room for 4 hours, and the above load was applied again, and the measured length _l1 was calculated using the following formula. ΔS = [(l ₀ - l ₁ )/l ₀ ] x 100 (%) Density ρ: A density gradient solution was prepared by continuously changing the mixing ratio of carbon tetrachloride and toluene, and a direct reading type manufactured by Murasakiyama Scientific Instruments Manufacturing Co., Ltd. It was measured by the density gradient tube method using a density measuring device. Birefringence Δn: Using white light as a light source, POH manufactured by Nihon Kogaku Kogyo Co., Ltd.
It was determined by the usual Bereck compensator method using a polarizing microscope. Intermediate elongation: In the load-elongation curve described above, it refers to the elongation when the strength determined by the following formula is exhibited. 4.5×drawn yarn fineness/840 Kg Example 1 Nylon 6 chips with ηr=3.65 containing 0.015% by weight of copper acetate, 0.1% by weight of potassium iodide and 0.1% by weight of 2-mercaptobenzimidazole were spun using an extruder spinning machine. The discharge amount was adjusted so that the total yarn fineness of the wound yarn was 850D. The cap used had a hole diameter of 0.3 mmφ and 306 holes, and the polymer temperature was 285°C. A 7μ cut non-woven fabric filter was used for filtration. Atmosphere 25cm below the cap at 295℃
The mixture was passed through a heating cylinder maintained at a constant temperature, and then passed through a 5 cm long Uniflow chimney to be rapidly cooled. Chimney wind conditions were set at 20℃ and 30m/min. Thereafter, 2% by weight of a non-aqueous oil was applied to the yarn using a guide oil supply device arranged in two stages. The spinning tension was adjusted by changing the distance from the spindle surface of the first stage oil supply device and the guide contact angle. Next, the yarn is taken up by a take-up roll that rotates at a predetermined speed, and then stretched continuously between a drawing roll (1DR), then 1DR, 2DR, and 2DR.
3DR and RR were each stretched, and 3DR and RR were relaxed. The yarn spinning conditions are shown in Table 1, and the obtained yarn properties are shown in Table 2. As is clear from Tables 1 and 2, when the degree of amorphous orientation is less than 0.7, the orientation of tie molecules is poor and high strength cannot be obtained. Moreover, when this value exceeds 0.8, tie molecule cleavage occurs, and the strength decreases on the contrary. Furthermore, when the γ-type crystal content (γ) is less than 0.3%, the uniformity of the fibers decreases and it is difficult to obtain high strength of the fibers.

【table】

【table】

【table】

[Table] Example 2 While combining two drawn yarns obtained in Example-1,
A raw cord was obtained by first twisting and final twisting at a twist rate of 320 T/m. Then, an adhesive application treatment was performed using a dipping machine manufactured by Ritzler.
It was immersed in the RFL solution, and the solution concentration and liquid draining device were adjusted so that the adhesion amount was 5%. The drying zone is passed through at 130℃ for 90 seconds at a constant length.
The heat treatment zone was passed through at 200° C. for 36 seconds while being stretched with a tension of 1 g/d. The normal zone was passed through at 195°C for 36 seconds with a tension of 0.7 g/d. The treated cord was subjected to rubber vulcanization and its residual strength was measured. The measurement conditions were as follows. Deep cords were arranged in parallel at a density of 24 cords/inch under no load, sandwiched between sheets of unvulcanized rubber with a thickness of 0.3 mm, placed in a mold, and heated at 160, 170, and 180 degrees Celsius using a heat press. Vulcanized and bonded for 30 minutes. After vulcanization, the mold was removed from the heat press and cooled with water, and the test piece was taken out from the mold at room temperature. After leaving it for 48 hours,
I tore off the cord and measured its strength. Table 3 shows the properties of the dip cord and the vulcanized cord. The method for measuring the cord characteristics is as follows. (1) Dry heat shrinkage rate (processing code) Measurement was performed in the same manner as for the yarn described above, except that the processing temperature was 177°C. (2) Intermediate elongation (treated cord) Similar to the T/D, E, and Mi measured above, in the load-extension curve of the treated cord, when the strength is 4.5 x cord fineness/(840 x 2) Kg. The elongation was determined and determined as an intermediate elongation. (3) Strength utilization rate = Treated cord strength / (Yarn strength × 2) × 100 (%) (4) GY fatigue life JIS method L-1017 3, 2, 2, 1-(1) A by Gutdeyer-Mallory I conducted the Chubu Huatei Gui Yu test. As is clear from Table 3, when the crosslinking freezing method melting point (Tm) is less than 188°C, the crystal integrity is low and the strength retention rate of the fiber is reduced. When this value is high, the crystal integrity is high, the structural change due to thermal stimulation such as the vulcanization process is small, and the strength retention rate is high. Furthermore, if the γ-type crystal content ratio (γ) exceeds 2%, the crystal stability will be low and structural changes will be large in response to thermal stimulation such as in the vulcanization process.
The strong retention rate will be lower. For the fibers of Inventive Example 2 and Comparative Examples 1 and 5, changes in strength due to higher processing are shown in FIG.
It is clear from this that the fibers of the present invention have high raw strength and also high strength after vulcanization.

【table】

[Table] [Effects of the Invention] The effects brought about by the fiber of the present invention are described below. (1) Fiber strength of 10g/d or more can be achieved.
Use in various industrial applications, such as tire cords, rubber reinforcing cords for conveyor belts, seat belts, sewing threads, fishing nets, various cover sheets, etc., improves their toughness and durability. (2) Since the intermediate elongation + dry yield of deep cord is low at 19% or less, it has excellent dimensional stability and high initial modulus, so it can be used for applications where polycapramide fibers have not been used until now. . (3) In particular, when made into tire cord, the strength retention rate after vulcanization is extremely high and the uniformity is excellent. When used for sagging, the weight of the fibers used can be reduced, resulting in a lightweight tire.

[Brief explanation of drawings]

FIG. 1 is a schematic front view showing one embodiment of the spinning process of the present invention. FIG. 2 is a schematic front view showing another embodiment of the method of the present invention. FIG. 3 is a graph showing changes in strength due to high-order processing of fibers. Y... Spun yarn, 1... Spinneret, 2... Heating cylinder, 3... Cooling device, 4... Oil supply device, 5... Taking-off roller, 6, 7, 8... Stretching roll, 9 ……
Relax roll, 10...winding machine.

Claims (1)

[Scope of Claims] 1. Consisting of an ε-capramide polymer having 95 mol% or more of repeating structural units, having a high degree of polymerization with a relative viscosity of sulfuric acid of 3.0 or more, and containing one or more copper salts and/or A polycapramide fiber containing an inorganic or organic antioxidant other than the copper salt, which also has the following properties. Tm≧188 (℃) fc≧0.93 0.83≧≧0.7 2≧γ≧0.3 (%) Here, Tm is γ after the fiber is treated with acetylene.
The amorphous part is cross-linked and frozen by radiation irradiation, and then
Melting point determined by DSC. fc is the degree of crystal orientation measured by X-rays. F is the degree of amorphous orientation measured by fluorescence photometry. γ is the percentage of γ-type crystals measured by X-rays. 2. The polycapramide fiber according to claim 1, wherein the strength T/D, the elongation E, and the initial tensile resistance Mi satisfy the following formula at the same time. T/D≧10 (g/d) 18≧E≧10 (%) Mi≧25 (g/d) 3 Dry yield ΔS at 150℃ is within the range of 6≧ΔS≧3 (%) The polycapramide fiber according to claim 1, characterized by: 4. The polycapramide fiber according to claim 1, wherein the density ρ is in the range of ρ≧1.145 (g/cc). 5. The polycapramide fiber according to claim 1, wherein the birefringence Δn is in the range of Δn≧0.057. 6 Consisting of an ε-capramide polymer with repeating structural units of 95 mol% or more, having a high degree of polymerization with a sulfuric acid relative viscosity of 3.0 or more, and containing one or more copper salts and/or inorganic materials other than the copper salts. Alternatively, when carrying out a direct spinning/drawing method in which a polycapramide-based polymer containing an organic antioxidant is melt-spun and wound at a speed of 5000 m/min or more, the melt-spun yarn is placed in an atmosphere of at least 10 cm below the spinneret of the polycapramide ( After passing through a zone surrounded by a cylinder heated to a temperature above (melting point + 30℃), it is rapidly cooled, and then a non-aqueous oil agent is applied under a tension that satisfies the following formula,
A method for producing a polycapramide fiber having the properties expressed by the following formulas at the same time, characterized by taking it off at a speed of 2000 m/min or more and then carrying out two or more stages of hot stretching while satisfying the formulas below. 5≧T/(N×V ^1.4 ×d ^0.2 ×10 ^-5 ≧1 …… 0.17≧(ηr ₁ − ηr ₂ )/ηr ₁ ≧0.05 … Here, T is the spinning tension (g weight) during oiling , n is the number of filaments of the fiber, V is the take-up roll speed (m/min), d is the single yarn fineness (denier) at the time of oiling,
ηr ₁ is the relative viscosity of sulfuric acid on the yarn on the take-up roll, ηr ₂
indicates the relative viscosity of sulfuric acid of the yarn after final winding. Tm≧188 (℃) … fc≧0.93 … 0.83≧−≧0.7 … 2≧γ≧0.3 (%) … Here, Tm is γ after the fiber is treated with acetylene.
The amorphous part is cross-linked and frozen by radiation irradiation, and then
Melting point determined by DSC. fc is the degree of crystal orientation measured by X-rays. is the degree of amorphous orientation measured by fluorescence polarization method. γ is the percentage of γ-type crystals measured by X-rays.