Heat-resistant high-toughness fibers, their manufacturing methods, and heat-resistant high-toughness membranes

Abstract

This invention provides heat-resistant, high-toughness fibers and films with an excellent balance of physical properties, including strength, elongation, and heat resistance. The heat-resistant, high-toughness fibers of this invention are characterized by a breaking strength of 3.5–15 cN / dtex, a breaking elongation of 5–30%, and a melting point of 290°C or higher. Furthermore, the method for manufacturing the heat-resistant, high-toughness fibers of this invention is characterized by using a copolymerized aromatic polyamide containing at least three monomer units selected from m-phenylenediamine, p-phenylenediamine, isophthalamide, and terephthalamide as the spinning raw material.

Description

Technical Field

[0001] This invention relates to heat-resistant, high-toughness fibers and methods for manufacturing the same, as well as heat-resistant, high-toughness films. More specifically, this invention relates to heat-resistant, high-toughness fibers with an excellent overall balance of physical properties, including strength, elongation, heat resistance, and optionally additional knot strength and / or conductivity, as well as methods for manufacturing the same, and heat-resistant, high-toughness films. Background Technology

[0002] In recent years, with the development of spinning technology and the industrialization of various fibers, fibers with corresponding properties and applications have been developed and manufactured by selecting the chemical structure and spinning conditions that constitute the fibers. Although high-strength and high-elasticity fibers can impart high-strength structures, they cannot mitigate large deformations due to their low elongation and thus break. There is a trade-off between the strength and elongation of these fibers, making it difficult to develop high-toughness fibers that satisfy both strength and elongation.

[0003] Examples of reports relating to high-toughness fibers include the following: For instance, Japanese Patent Application Publication No. 59-100710 (Patent Document 1) reports obtaining high-toughness polyester fibers with a strength of 15-25 g / dtex and an elongation of 15-25% by heat shrinking super-stretched polyethylene fibers. Additionally, Japanese Patent Application Publication No. 2000-144527 (Patent Document 2) reports a method for obtaining polyester fibers with a strength of 8-9 g / dtex and an elongation of 10-15% by adjusting the oiling and bundling positions. Furthermore, Japanese Patent Application Publication No. 2008-308786 (Patent Document 3) reports obtaining polyester fibers with a strength of 8-10 cN / dtex and an elongation of 20-25% or more by controlling the temperature process on the spinning line; however, these are all general-purpose fibers with low heat resistance.

[0004] On the other hand, in addition to strength, heat resistance is another property required in material development. For example, fibers made of fully aromatic polyamides (sometimes called aromatic polyamide fibers) are particularly useful as high-strength, heat-resistant, and flame-retardant fibers.

[0005] For example, para-phenylenediamine-based fully aromatic polyamide fibers are widely used as reinforcement materials for various base materials and industrial materials such as ropes due to their high strength and high elastic modulus. Additionally, meta-phenylenediamine-based fully aromatic polyamide fibers are soft fibers with heat resistance, and can be used in applications such as protective clothing and disaster relief safety garments, as well as in industrial applications requiring heat resistance, such as rubber reinforcement materials.

[0006] As for the mechanical properties of these aramid fibers, examples of para-type fibers include a breaking strength of 15–20 cN / dtex and a breaking elongation of 1–5% (Dupont Corporation's "Kevlar" (registered trademark) and Teijin Corporation's "Twaron" (registered trademark)). Examples of meta-type fibers include a breaking strength of 3–6 cN / dtex and a breaking elongation of 30–60% (Dupont Corporation's "Nomex" (registered trademark) and Teijin Corporation's "Conex" (registered trademark)). Applications were developed taking these fiber properties into consideration.

[0007] However, when using aramid fibers, para-type fibers are generally used in applications requiring both heat resistance and high strength, but this is limited to uses where deformation is less likely. On the other hand, meta-type fibers are used in applications requiring both heat resistance and flexibility, but this comes at the cost of strength.

[0008] Therefore, it would be useful to obtain synthetic fibers that have heat resistance comparable to aramid fibers and achieve a balance between strength and elongation, but this has not been achieved in the prior art.

[0009] Furthermore, membranes with the required properties and applications have also been developed and manufactured. While high-strength, highly elastic membranes can impart high-strength structures, their low elongation means they cannot mitigate large deformations and may break. There is a trade-off between the strength and elongation of these membranes, making it difficult to develop high-toughness membranes that satisfy both strength and elongation.

[0010] Examples of reports relating to heat-resistant films include the following. For instance, Japanese Patent Application Publication No. 2003-176354 (Patent Document 10) reports a transparent film composed of a polymer containing a polyimide backbone with excellent heat resistance, but its glass transition temperature is around 120-160°C, and it may deform at high temperatures. Japanese Patent Application Publication No. Hei 3-138129 (Patent Document 11) reports a high-strength film with even better heat resistance, but its maximum strength is only 160 MPa, and on the other hand, its heat shrinkage rate at 250°C is a high value of less than 20%, which is insufficient for use in high-temperature regions.

[0011] Existing technical documents

[0012] Patent documents

[0013] Patent Document 1: Japanese Patent Application Publication No. 59-100710

[0014] Patent Document 2: Japanese Patent Application Publication No. 2000-144527

[0015] Patent Document 3: Japanese Patent Application Publication No. 2008-308786

[0016] Patent Document 4: Japanese Patent Application Publication No. 63-235521

[0017] Patent Document 5: Japanese Patent Application Publication No. 5-9867

[0018] Patent Document 6: Japanese Patent Application Publication No. 2019-157285

[0019] Patent Document 7: Japanese Patent Application Publication No. 2-216264

[0020] Patent Document 8: Japanese Patent Application Publication No. 2006-2213

[0021] Patent Document 9: Japanese Patent Application Publication No. 2006-342471

[0022] Patent Document 10: Japanese Patent Application Publication No. 2003-176354

[0023] Patent Document 11: Japanese Patent Application Publication No. 3-138129 Summary of the Invention

[0024] As described in the background above, the object of the present invention is to provide heat-resistant, high-toughness fibers and heat-resistant, high-toughness films that have high heat resistance and achieve a balance between strength and elongation. Another object of the present invention is to provide heat-resistant, high-toughness fibers that also have excellent knot strength and / or conductivity, and films that have high heat resistance and achieve a balance between strength and elongation.

[0025] To address the aforementioned issues, the inventors conducted in-depth research and discovered that by copolymerizing multiple specific monomers in a specific ratio to obtain a polymer that can be processed into fibers or films, heat-resistant and high-toughness fibers or films exhibiting high heat resistance and achieving a balance between strength and elongation can be obtained, thus completing this invention. Furthermore, the inventors found that the knot strength and / or conductivity can be further improved in such heat-resistant and high-toughness fibers, thus completing this invention.

[0026] According to the present invention, the following configuration can be provided:

[0027] 1. A heat-resistant and high-toughness fiber, characterized in that it has a breaking strength of 3.5–15 cN / dtex, a breaking elongation of 5–30%, and a melting point above 290°C.

[0028] 2. The heat-resistant and high-toughness fiber according to claim 1, wherein the heat-resistant and high-toughness fiber contains a copolymerized aromatic polyamide polymer, the copolymerized aromatic polyamide polymer containing at least three monomer units selected from m-phenylenediamine, p-phenylenediamine, isophthalamide, and terephthalamide.

[0029] 3. The heat-resistant, high-toughness fiber according to claim 2 above, wherein the molar ratio of the m-phenylenediamine and / or the isophthaloyl monomer unit to the p-phenylenediamine and / or the terephthaloyl monomer unit is in the range of 10 or more and less than 70:90 and greater than 30.

[0030] 4. The heat-resistant, high-toughness fiber according to any one of 1 to 3 above, wherein the breaking strength is 7 to 15 cN / dtex, the breaking elongation is 10 to 30%, and the dry heat dimensional change rate at 250°C is less than 2%.

[0031] 5. The heat-resistant, high-toughness fiber according to 4 above, wherein the knotting strength is further 4.4–5.6 cN / dtex.

[0032] 6. The heat-resistant, high-toughness fiber according to 4 or 5 above, wherein the molar ratio of the m-phenylenediamine and / or the isophthaloyl monomer unit to the p-phenylenediamine and / or the terephthaloyl monomer unit is in the range of 40 or more and less than 70:60 and greater than 30.

[0033] 7. The heat-resistant, high-toughness fiber according to any one of claims 1 to 3 above, wherein the tensile strength is 8.0 cN / dtex or more and less than 15.0 cN / dtex, the elongation at break is greater than 5.0% and less than 20.0%, and the dimensional change rate under dry heat at 300°C is less than 5%.

[0034] 8. The heat-resistant, high-toughness fiber according to claim 7 above, wherein the molar ratio of the m-phenylenediamine and / or the isophthaloyl monomer unit to the p-phenylenediamine and / or the terephthaloyl monomer unit is in the range of 10 or more and less than 40:90 and greater than 60.

[0035] 9. The heat-resistant, high-toughness fiber according to any one of claims 1 to 3 above, wherein the fiber contains conductive microparticles with a resistivity of 10 Ω·cm. 3 Below Ωcm, and with a fracture strength of 3.5–10 cN / dtex,

[0036] 10. The heat-resistant, high-toughness fiber according to claim 9 above, wherein it contains 6 to 40% by mass of the aforementioned conductive microparticles.

[0037] 11. The heat-resistant, high-toughness fiber according to 9 or 10 above, wherein the conductive particles are conductive carbon black.

[0038] 12. The heat-resistant, high-toughness fiber according to any one of 9 to 11 above, wherein the molar ratio of the m-phenylenediamine and / or the isophthaloyl monomer unit to the p-phenylenediamine and / or the terephthaloyl monomer unit is in the range of 50 or more and less than 70:50 and greater than 30.

[0039] 13. A method for manufacturing a heat-resistant and high-toughness fiber, characterized in that it includes the following steps (1) to (6):

[0040] (1) Prepare a copolymerized aromatic polyamide polymer containing at least three monomer units selected from m-phenylenediamine, p-phenylenediamine, isophthalamide, and terephthalamide, wherein the molar ratio of the m-phenylenediamine and / or the isophthalamide monomer unit to the p-phenylenediamine and / or the terephthalamide monomer unit is in the range of 10 or more and less than 70:90 and greater than 30, and the weight-average molecular weight is 400,000 to 1,000,000.

[0041] (2) Dissolve the copolymerized aromatic polyamide polymer in a solvent to prepare a spinning solution.

[0042] (3) The spinning solution is passed through the spinning head and spun into a coagulation bath to obtain coagulated yarn.

[0043] (4) The coagulated filament is washed with an aqueous cleaning bath, and then stretched in a boiling water stretching bath at a ratio of 1.1 to 5.0 times to obtain the fiber.

[0044] (5) The fiber was subjected to dry heat treatment in the range of 100–250°C, and then,

[0045] (6) While applying heat treatment to the dry heat-treated fiber in the range of 290 to 380°C, hot stretching is performed in the range of 2.0 to 10.0 times the stretch ratio.

[0046] 14. The manufacturing method according to 13 above, wherein the spinning solution is prepared by dissolving the copolymerized aromatic polyamide polymer in an amide solvent at a concentration in the range of 5 to 30% by mass, and the coagulation bath contains 1 to 20% by mass of the amide solvent.

[0047] 15. The manufacturing method according to 13 above, wherein the spinning solution is prepared by dissolving the copolymerized aromatic polyamide polymer in concentrated sulfuric acid with a concentration of 95% or higher at a concentration ranging from 5% to 30% by mass, and the coagulation bath contains water.

[0048] 16. A heat-resistant and high-toughness film, wherein the heat-resistant and high-toughness film has a tensile strength of 80-150 MPa, an elongation at break of 5-30%, a glass transition temperature of 250°C or higher, and a heat shrinkage rate of 5% or less at 300°C, and wherein the heat-resistant and high-toughness film is composed of a copolymerized aromatic polyamide polymer, wherein the copolymerized aromatic polyamide polymer contains monomer units selected from three of the following: m-phenylenediamine, p-phenylenediamine, isophthalamide, and terephthalamide; or contains two monomer units: m-phenylenediamine and terephthalamide; or contains two monomer units: p-phenylenediamine and isophthalamide.

[0049] The heat-resistant, high-toughness fiber obtained in this invention possesses an excellent balance of properties, exhibiting heat resistance capable of withstanding operating environments above 250°C while maintaining a tensile strength of 3.5–15 cN / dtex and an elongation at break of 5–30%. Therefore, it is suitable for applications such as protective clothing where strength and softness are added to the heat resistance, and rubber reinforcement applications requiring elongation. Furthermore, the heat-resistant, high-toughness film obtained in this invention possesses an excellent balance of properties, including a tensile strength of 80–150 MPa, an elongation at break of 5–30%, a glass transition temperature above 250°C, and a heat shrinkage rate of less than 5% at 300°C. Therefore, it is suitable for applications requiring strength and elongation in high-temperature regions. Detailed Implementation

[0050] The present invention will now be described in detail.

[0051] The heat-resistant, high-toughness fiber of the present invention is characterized by a breaking strength of 3.5–15 cN / dtex, a breaking elongation of 5–30%, and a melting point of 290°C or higher. The polymer constituting this heat-resistant, high-toughness fiber is generally a fully aromatic polyamide (hereinafter sometimes referred to as aromatic polyamide), containing copolymers of aromatic diamine components, particularly meta- and / or para-type, and meta- and / or para-type aromatic dicarboxylic acid components.

[0052] In the heat-resistant and high-toughness fiber of the present invention, a fully aromatic polyamide composed of a copolymerized aromatic polyamide polymer is randomly copolymerized, preferably containing at least three monomer units selected from m-phenylenediamine, p-phenylenediamine, isophthalamide, and terephthalamide. Examples of combinations of these monomer units are shown in Table 1 below.

[0053] Furthermore, the heat-resistant and high-toughness film of the present invention contains three monomer units selected from m-phenylenediamine, p-phenylenediamine, isophthalamide, and terephthalamide, or contains two monomer units, namely m-phenylenediamine and terephthalamide, or contains two monomer units, namely p-phenylenediamine and isophthalamide. Examples of combinations of these monomer units, 1 to 4, 6, and 7, are shown in Table 1 below.

[0054] [Table 1]

[0055] m-phenylenediamine p-phenylenediamine isophthaloyl monomer terephthaloyl monomer Example 1 ○ - ○ ○ Example 2 - ○ ○ ○ Example 3 ○ ○ ○ - Example 4 ○ ○ - ○ Example 5 ○ ○ ○ ○ Example 6 ○ - ○ Example 7 - ○ ○ -

[0056] In the above combination examples, the heat-resistant and high-toughness fiber generally preferably contains the three monomer units shown in Examples 1 to 4. Depending on the application, it is sometimes more preferable to contain the four monomer units shown in Example 5 or the three monomer units shown in Example 4.

[0057] In the above combination examples, the heat-resistant and high-toughness film generally contains the three monomer units shown in Examples 1 to 4 or the two monomer units shown in Examples 6 and 7.

[0058] In the heat-resistant and high-toughness fiber of the present invention, the molar ratio of m-phenylenediamine and / or isophthaloyl monomer units to p-phenylenediamine and / or terephthaloyl monomer units is preferably in the range of 10 or more and less than 70:90 and greater than 30.

[0059] In the first embodiment of the heat-resistant, high-toughness fiber of the present invention, the breaking strength can be 7 to 15 cN / dtex, the breaking elongation can be 10 to 30%, and the melting point can be 290°C or higher. Here, the molar percentage of m-phenylenediamine and / or isophthalamide monomer units is preferably 40% or more and less than 70% overall; the molar percentage of p-phenylenediamine and / or terephthalamide monomer units is preferably 60% or less and greater than 30% overall; the molar percentage of m-phenylenediamine and / or isophthalamide monomer units is more preferably 50% or more and less than 70% overall; the molar percentage of p-phenylenediamine and / or terephthalamide monomer units is more preferably 50% or less and greater than 30% overall; the molar percentage of m-phenylenediamine and / or isophthalamide monomer units is particularly preferably 50% or more and less than 67% overall; and the molar percentage of p-phenylenediamine and / or terephthalamide monomer units is particularly preferably 50% or less and greater than 33% overall. If the molar percentage of m-phenylenediamine and / or isophthalamide monomer units is 70% or more, the target strength may not be achieved. Additionally, if the molar percentage of m-phenylenediamine and / or isophthaloyl monomer units is less than 40, the resulting polymer may sometimes be insoluble in the amide solvents described later and cannot be spun.

[0060] The breaking strength of the heat-resistant, high-toughness fiber of the first embodiment is 7 to 15 cN / dtex, preferably 8.0 cN / dtex or higher. If the breaking strength is less than 3.5 cN / dtex, the high toughness required for this invention is sometimes insufficient. Furthermore, the breaking elongation of the heat-resistant, high-toughness fiber of the first embodiment is generally 10% to 30%, preferably 15% to 25%, and more preferably 20% to 25% or higher. If the breaking elongation is less than 10%, the high toughness is sometimes not fully realized due to insufficient elongation. On the other hand, if the breaking elongation is greater than 30%, sufficient strength is sometimes not obtained.

[0061] The melting point of the heat-resistant, high-toughness fiber of the first embodiment needs to be 290°C or higher, preferably 300°C or higher. If the melting point is lower than 290°C, its performance as a heat-resistant fiber cannot be fully realized. Furthermore, in the heat-resistant, high-toughness fiber of the first embodiment, the dry heat dimensional change rate at 250°C is preferably less than 2%, more preferably 1.5% or less, even more preferably 1.0% or less, and particularly preferably 0.5% or less. If the dry heat dimensional change rate is 2% or higher, its performance as a heat-resistant fiber may sometimes not be fully realized.

[0062] In the second embodiment of the heat-resistant, high-toughness fiber of the present invention, the breaking strength can be 7.0 to 15.0 cN / dtex, the knot strength can be 4.4 to 5.6 cN / dtex (42.3% to 50%), the elongation at break can be 10 to 30%, and the melting point can be 290°C or higher. Examples of reported results related to high-knot strength fibers include the following: For example, Japanese Patent Application Publication No. 63-235521 (Patent Document 4) reports the obtaining of high-toughness para-aramid fibers with a strength of 21.4 g / de and a knot strength of 7.5 to 8.4 g / de (36% to 39%) by subjecting para-oriented aramid fibers to low-temperature pre-drying and steam treatment. Furthermore, Japanese Patent Application Publication No. 5-9867 (Patent Document 5) reports a method for obtaining fibers with a strength of 22.5–23.4 g / de and a knot strength of 7.1–8.2 g / de (30–36%) by attaching organosilicon microparticles to the surface of para-aramid fibers. Additionally, Japanese Patent Application Publication No. 2019-157285 (Patent Document 6) reports a method for obtaining high-strength fibers for weaving with a strength of 20.2 cN / de and a knot strength of 7.8 cN / de (39%) or higher by using a fiber treatment agent. However, these reported examples all relate to para-aramid fibers, which, while possessing heat resistance, have a low modulus of elasticity. The heat-resistant, high-toughness fiber of the second aspect of the present invention possesses heat resistance capable of withstanding operating environments above 250°C, and simultaneously exhibits an excellent balance of the aforementioned combination of breaking strength, knot strength, and elongation at break, making it suitable for use in safety ropes, fall arrest materials, and the like.

[0063] In the heat-resistant, high-toughness fiber of the second type, the molar percentage of m-phenylenediamine and / or isophthalamide monomer units is preferably 50% or more and less than 68% overall; the molar percentage of p-phenylenediamine and / or terephthalamide monomer units is preferably 50% or less and greater than 32% overall; the molar percentage of m-phenylenediamine and / or isophthalamide monomer units is more preferably 55% or more and less than 63% overall; the molar percentage of p-phenylenediamine and / or terephthalamide monomer units is more preferably 45% or less and greater than 37% overall; the molar percentage of m-phenylenediamine and / or isophthalamide monomer units is particularly preferably 55% or more and less than 60% overall; and the molar percentage of p-phenylenediamine and / or terephthalamide monomer units is particularly preferably 45% or less and greater than 40% overall. If the molar percentage of m-phenylenediamine and / or isophthalamide monomer units is greater than 68, the target knot strength may not be obtained. In addition, if the molar percentage of m-phenylenediamine and / or isophthaloyl monomer units is less than 50, the resulting polymer is sometimes insoluble in the amide solvents described later and cannot be spun.

[0064] The knot strength of the heat-resistant, high-toughness fiber, as the second type, is 4.4–5.6 cN / dtex (42.3%–50%), preferably 4.9–5.6 cN / dtex (45%–50%). If the knot strength is less than 4.4 cN / dtex, the target strength may not be obtained. On the other hand, if the knot strength is greater than 5.6 cN / dtex, the target elongation at break may not be obtained. It should be noted that the percentage (%) in parentheses for the knot strength described in this specification represents the ratio of knot strength to breaking strength; the higher the ratio of knot strength, the better the balance between the fiber's softness and strength.

[0065] Furthermore, the tensile strength of the heat-resistant, high-toughness fiber of the second embodiment is 7.0 to 15.0 cN / dtex, with a lower limit more preferably 8.0 cN / dtex or higher. When the tensile strength is less than 7.0 cN / dtex, the target strength is sometimes not obtained. Additionally, the elongation at break of the heat-resistant, high-toughness fiber of the second embodiment is generally 10% to 30%, preferably 15% to 25%, more preferably 20% to 25%. When the elongation at break is less than 10%, the balanced physical properties required for the present invention are sometimes insufficient. If the elongation at break is greater than 30%, sufficient strength is sometimes not obtained.

[0066] The melting point of the heat-resistant, high-toughness fiber of the second type is generally 290°C or higher, preferably 300°C or higher. If the melting point is lower than 290°C, its performance as a heat-resistant fiber may not be fully realized. Furthermore, in the heat-resistant, high-toughness fiber of the second type, the dry heat dimensional change rate at 250°C is generally preferably less than 2%, more preferably 1.5% or less, even more preferably 1.0% or less, and particularly preferably 0.5% or less. If the dry heat dimensional change rate is 2% or higher, its performance as a heat-resistant fiber may not be fully realized.

[0067] The weight-average molecular weight of the heat-resistant, high-toughness fiber used in the second method is preferably between 400,000 and 1,000,000, according to the analytical method described later. When the weight-average molecular weight of the heat-resistant, high-toughness fiber is less than 400,000, the breaking strength sometimes decreases significantly. Furthermore, when the molecular weight of the heat-resistant, high-toughness fiber is greater than 1,000,000, the viscosity is too high when spinning the fully aromatic polyamide solution from the spinneret, making it difficult to handle and sometimes requiring specialized equipment.

[0068] The heat-resistant, high-toughness fiber of the second type possesses a well-balanced physical property, exhibiting both excellent strength and knot strength. Furthermore, it possesses heat resistance and flame retardancy, making it effectively applicable as a fall arresting material for catching concrete structures, soil, sand, snow, and other structures, as well as fiber products such as safety ropes and safety nets to ensure the safety of workers at heights. In the aforementioned applications such as fall arresting materials, safety ropes, and safety nets, the heat-resistant, high-toughness fiber of the second type is preferably 30-100% by weight, more preferably 50-100% by weight, further preferably 80-100% by weight, and most preferably 100% by weight. If the content of the copolymerized aramid fiber is less than 50%, the characteristics of the heat-resistant, high-toughness fiber of the present invention may not be fully utilized.

[0069] In the third embodiment of the heat-resistant, high-toughness fiber of the present invention, the breaking strength can be 8.0 cN / dtex or more and less than 15.0 cN / dtex, the breaking elongation can be greater than 5.0% and less than 20.0%, and the dry heat dimensional change rate at 300°C can be less than 5%. Here, the molar percentage of m-phenylenediamine and / or isophthalamide monomer units is preferably 10% or more and less than 40% of the total; the molar percentage of p-phenylenediamine and / or terephthalamide monomer units is preferably 90% or less and greater than 60% of the total; the molar percentage of m-phenylenediamine and / or isophthalamide monomer units is more preferably 20% or more and less than 40% of the total; and the molar percentage of p-phenylenediamine and / or terephthalamide monomer units is more preferably 80% or less and greater than 60% of the total. When both m-phenylenediamine and isophthalamide monomer units are present, the total of these two monomer units (m-phenylenediamine and isophthalamide monomer units) is used. Furthermore, when both p-phenylenediamine and terephthalamide monomer units are present, the total amount (p-phenylenediamine and terephthalamide monomer units) is also considered. When the molar percentage of m-phenylenediamine and / or isophthalamide monomer units is 40% or higher, the target strength and thermal stability may not be achieved. Additionally, when the molar percentage of m-phenylenediamine and / or isophthalamide monomer units is less than 10%, the resulting polymer may be insoluble in the amide solvents described later, making spinning impossible.

[0070] The breaking strength of the heat-resistant, high-toughness fiber of the third embodiment is generally 8.0 cN / dtex or higher and less than 15.0 cN / dtex, with a lower limit more preferably 9.0 cN / dtex or higher. When the breaking strength is less than 8.0 cN / dtex, the strength required for the high toughness of the present invention is sometimes insufficient. Furthermore, the elongation at break is generally greater than 5.0% and less than 20%, preferably 7.0% to 15.0%, more preferably 10.0% to 15.0%. When the elongation at break is less than 5.0%, the elongation is sometimes insufficient, and the high toughness cannot be fully utilized. On the other hand, if the elongation at break is greater than 20.0%, sufficient strength is sometimes not obtained. The dry heat dimensional change rate of the heat-resistant, high-toughness fiber of the third embodiment at 300°C is generally less than 5%, preferably 4% or less. If the dry heat dimensional change rate is 5% or higher, the performance as a heat-resistant fiber cannot be fully utilized.

[0071] In a fourth embodiment of the heat-resistant, high-toughness fiber of the present invention, the fiber may contain conductive microparticles, and the resistivity may be 10⁻⁶. 3With a tensile strength of less than Ωcm, the tensile strength can be 3.5–10 cN / dtex, the elongation at break can be 10–30%, and the melting point can be above 290°C. Generally, conductive fibers, depending on their application, can not only impart conductivity but also, appropriately, impart electrical dissipation properties. Based on these properties, conductive fibers, primarily general-purpose fibers, are used in clothing and industrial applications, and are now also important functional fibers. Various manufacturing methods have been disclosed for conductive fibers, including methods that impart conductivity by metallizing the fiber surface and methods that impart conductivity by filling conductive particles into the raw polymer and then spinning it. On the other hand, heat resistance is an example of a property required in material development. For example, fibers composed of fully aromatic polyamides (sometimes called aromatic polyamide fibers) are particularly useful as high-strength, heat-resistant, and flame-retardant fibers. Currently, commonly used conductive fibers include nylon and acrylic fibers, which are sometimes unsuitable for applications requiring heat resistance. However, if heat-resistant fibers such as fully aromatic polyamides can be made conductive, an expansion of applications can be expected. To date, attempts have been made to impart conductivity to such fully aromatic polyamide fibers. For example, in Japanese Patent Application Publication No. 2-216264 (Patent Document 7) and Japanese Patent Application Publication No. 2006-2213 (Patent Document 8), conductivity was achieved by coating the surface of aromatic polyamide fibers with copper sulfide or silver. In Japanese Patent Application Publication No. 2006-342471 (Patent Document 9), a method for obtaining conductive para-type aromatic polyamide fibers by adding carbon nanotubes and conductive microparticles other than carbon nanotubes to a spinning solution and then spinning was disclosed. However, the method of coating the fiber surface to impart conductivity requires surface treatment, which presents a problem in terms of productivity, and in terms of quality, durability due to wear and other factors is problematic. In addition, in the method of adding conductive microparticles to resin and mixing and then spinning, the conductivity durability is high because the conductive microparticles are retained inside the fiber, but the mechanical properties of the fiber decrease, and sufficient strength cannot be obtained. This fourth type of conductive, heat-resistant, high-toughness fiber exhibits heat resistance capable of withstanding operating environments above 250°C, while also displaying a resistivity of 10⁻⁶ in addition to the aforementioned breaking strength and elongation at break. 3 With such high conductivity as below Ωcm, it can be appropriately used, for example, in protective clothing applications requiring strength, softness, and high static electricity resistance.

[0072] In the heat-resistant, high-toughness fiber of the fourth embodiment of the present invention, the molar percentage of m-phenylenediamine and / or isophthalamide monomer units is preferably 50% or more and less than 70% overall, the molar percentage of p-phenylenediamine and / or terephthalamide monomer units is preferably 50% or less and greater than 30% overall, the molar percentage of m-phenylenediamine and / or isophthalamide monomer units is more preferably 50% or more and less than 67% overall, and the molar percentage of p-phenylenediamine and / or terephthalamide monomer units is more preferably 50% or less and greater than 33% overall. If the molar percentage of m-phenylenediamine and / or isophthalamide monomer units is 70% or more, the target strength may not be achieved. On the other hand, if the molar percentage of m-phenylenediamine and / or isophthalamide monomer units is less than 50%, the resulting polymer may be insoluble in the amide solvent described later and cannot be spun.

[0073] The resistivity of heat-resistant, high-toughness fibers, used in the fourth method, is generally 10. 3 The resistivity is below Ωcm, more preferably below 700 Ωcm, further preferably below 500 Ωcm, and most preferably below 200 Ωcm. The lower the resistivity, the more sufficient the electrostatic properties can be obtained, and therefore it is preferred. As described below, it is preferred to adjust it in a timely manner in view of the balance with the target properties such as strength, elongation, and spinnability.

[0074] Furthermore, the breaking strength of the heat-resistant, high-toughness fiber of the fourth type is generally 3.5 to 10 cN / dtex, preferably 4.0 to 10.0 cN / dtex, and more preferably 4.0 to 7.0 cN / dtex. When the breaking strength is less than 3.5 cN / dtex, the strength is insufficient for applications such as protective clothing, which are the purpose of this invention. Additionally, the breaking elongation of the conductive, heat-resistant, high-toughness fiber of this invention is 10% to 30%, more preferably 10% to 20%. When the breaking elongation is less than 10%, the elongation is insufficient, and therefore the softness cannot always be fully utilized. The melting point of the conductive, heat-resistant, high-toughness fiber of this invention is generally 290°C or higher, more preferably 300°C or higher. If the melting point is lower than 290°C, the performance as a heat-resistant fiber cannot always be fully utilized.

[0075] Furthermore, the heat-resistant, high-toughness film of the present invention generally has a tensile strength of 80–150 MPa, an elongation at break of 5–30%, a glass transition temperature of 250°C or higher, and a thermal shrinkage rate of 5% or less at 300°C. The tensile strength is generally 80–150 MPa, preferably 100–150 MPa. When the tensile strength is less than 80 MPa, the strength is insufficient for use as a heat-resistant film. Additionally, the elongation at break of the heat-resistant, high-toughness film of the present invention is 5%–30%, more preferably 5%–20%. When the elongation at break is less than 5%, the elongation is insufficient, and therefore the flexibility cannot always be fully utilized. Furthermore, the glass transition temperature is generally 250°C or higher, preferably 280°C or higher. If the glass transition temperature is lower than 250°C, the performance as a heat-resistant film cannot always be fully utilized. Furthermore, the dry heat dimensional change rate at 300°C is generally 5% or less, preferably 4% or less. If the dry heat dimensional change rate is greater than 5%, the performance as a heat-resistant film cannot always be fully utilized.

[0076] Furthermore, the heat-resistant and high-toughness film of the present invention is made of a copolymerized aromatic polyamide polymer, which generally contains three monomer units selected from m-phenylenediamine, p-phenylenediamine, isophthalamide, and terephthalamide, or contains two monomer units, namely m-phenylenediamine and terephthalamide, or contains two monomer units, namely p-phenylenediamine and isophthalamide. In the combination examples in Table 1 above, it is generally preferred to contain the three monomer units shown in Examples 1 to 4 and the two monomer units shown in Examples 6 to 7, and sometimes it is more preferred to contain the two monomer units shown in Examples 6 to 7.

[0077] Furthermore, the molar percentage of m-phenylenediamine and / or isophthalamide monomer units is preferably 10 or more and less than 60% of the total, the molar percentage of p-phenylenediamine and / or terephthalamide monomer units is preferably 90 or less and greater than 40% of the total, the molar percentage of m-phenylenediamine and / or isophthalamide monomer units is more preferably 20 or more and less than 60% of the total, and the molar percentage of p-phenylenediamine and / or terephthalamide monomer units is more preferably 80 or less and greater than 40% of the total. If the molar percentage of m-phenylenediamine and / or isophthalamide monomer units is 60 or more, the target strength may not be achieved. On the other hand, if the molar percentage of m-phenylenediamine and / or isophthalamide monomer units is less than 10, the resulting polymer may be insoluble in the amide solvents described later, making film formation impossible.

[0078] Examples of aromatic diamine components that can be used as raw materials for fully aromatic polyamides include m-phenylenediamine or p-phenylenediamine, 3,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl sulfone, and derivatives having halogenated or alkyl substituents having 1 to 3 carbon atoms on these aromatic rings.

[0079] As raw materials for the aromatic dicarboxylic acid component constituting the fully aromatic polyamide of the present invention, aromatic dicarboxyl halides can be cited as examples. Examples of meta-type aromatic dicarboxyl halides include isophthaloyl chloride, isophthaloyl bromide, and other isophthaloyl halides, as well as derivatives having halogenated alkoxy groups having 1 to 3 carbon atoms on these aromatic rings. Similarly, examples of para-type aromatic dicarboxyl halides include terephthaloyl chloride, terephthaloyl bromide, and other terephthaloyl halides, as well as derivatives having halogenated alkoxy groups having 1 to 3 carbon atoms on these aromatic rings.

[0080] Examples of polymerization methods for the fully aromatic polyamide of the present invention include: a method for separating poly(m-phenylene isophthalamide) polymer powder by contacting an organic solvent system (e.g., tetrahydrofuran) containing m-phenylene diamine and isophthaloyl chloride, which is a poor solvent for generating polyamide, with an aqueous solution system containing an inorganic acid acceptor and a soluble neutral salt (interfacial polymerization, Japanese Patent Publication No. 47-10863); or a method for solution polymerization of the above-mentioned diamine and acyl chloride in an amide solvent followed by neutralization with calcium hydroxide, calcium oxide, etc. (solution polymerization, Japanese Patent Application Publication No. 8-074121, Japanese Patent Application Publication No. 10-88421), etc., but not limited to these methods.

[0081] For the weight-average molecular weight of the fully aromatic polyamide copolymer (also known as a copolymerized aromatic polyamide polymer) used in this invention, from the viewpoint of forming fibers with practical tensile strength, a weight-average molecular weight of 400,000 to 1,000,000 is preferred according to the analytical method described later. It should be noted that when the weight-average molecular weight is less than 400,000, not only is the tensile strength significantly reduced, but stable spinning is sometimes impossible. Furthermore, when the molecular weight exceeds 1,000,000, the viscosity is too high when spinning the fully aromatic polyamide solution described later, making the process difficult and sometimes requiring specialized equipment.

[0082] The polymers within the molecular weight range specified in this invention can be mixtures of low-molecular-weight polymers and high-molecular-weight polymers. The overall molecular weight can be adjusted to be within the specified molecular weight range by adjusting the mixing ratio. For example, mixing a polymer with a weight-average molecular weight of 200,000 with a polymer with a weight-average molecular weight of 800,000 results in a polymer with a weight-average molecular weight of 600,000, which falls within the molecular weight range specified in this invention. Therefore, there is no problem using such a mixture.

[0083] The fully aromatic polyamide fiber of the present invention is manufactured using the fully aromatic polyamide obtained by the above-described manufacturing method, and through the following spinning solution preparation process, spinning and coagulation process, washing process, boiling water stretching process, dry heat treatment process, and hot stretching process.

[0084] [Spinning solution preparation process]

[0085] In the spinning solution preparation process, the fully aromatic polyamide of the present invention is dissolved in a solvent to prepare the spinning solution (also called the spinning concentrate or spinning concentrate). Amide solvents are typically used in the preparation of the spinning solution, examples of which include N-methyl-2-pyrrolidone (NMP), dimethylformamide (DMF), and dimethylacetamide (DMAc). From the viewpoint of solubility and operational safety, NMP or DMAc is preferred. Alternatively, concentrated sulfuric acid can be used as the solvent in the present invention. When using concentrated sulfuric acid, a concentration of 95% or higher is preferred, and more preferably 98% or higher. When using concentrated sulfuric acid, air-gap spinning using water can also be performed in the coagulation process described later.

[0086] As for the solution concentration, an appropriate concentration can be selected from the viewpoint of the coagulation rate in the subsequent spinning and coagulation process and the solubility of the polymer. Generally, a range of 5 to 30% by mass is required. Particularly in the first, second, and fourth embodiments of the present invention, a solution concentration of 10 to 30% by mass is preferred, and a range of 15 to 25% by mass is more preferred for achieving more stable spinning. On the other hand, in the third embodiment of the present invention, a solution concentration of 5 to 25% by mass is preferred, and a range of 7 to 20% by mass is more preferred for achieving more stable spinning.

[0087] When manufacturing the heat-resistant, high-toughness fiber as the fourth aspect of the present invention, it is preferable to add 6 to 40% by mass of conductive microparticles relative to the fully aromatic polyamide constituting the fiber. This addition amount is more preferably 10 to 35% by mass, and even more preferably 20 to 30% by mass. If the concentration of conductive microparticles is less than 6% by mass, the target conductivity cannot be achieved, or conversely, if it exceeds 40% by mass, the target strength may sometimes not be obtained. Here, the conductive microparticles are not particularly limited to substances that inherently exhibit conductivity, such as metal microparticles, metal oxides, or carbon black (also called conductive carbon black), and do not hinder fiber formation; however, from a manufacturing technology perspective, conductive carbon black is preferred in the present invention.

[0088] The surface resistivity of conductive carbon black is preferably 10 to 10⁻⁶ when measured at 20°C and 65% humidity. 8 Ω, more preferably 10 2 ~10 6 Ω, more preferably 10 3 ~10 5 Ω. If the surface resistivity of the conductive carbon black is within the above range, conductive, heat-resistant, and highly tough fibers with the target resistivity of the present invention can be obtained, and are therefore preferred.

[0089] It should be noted that the surface resistivity (Ω) of the conductive carbon black was determined as follows: In the polymer solution obtained in Example 10 described later, 25% conductive carbon black was added relative to the polymer, coated onto glass cloth using a 3 ml coating machine, washed and dried, and then heat-treated in an electric furnace at 330°C for 2 minutes to obtain a specimen. The surface resistivity was measured using a HIRESTA UP (manufactured by Mitsubishi Chemical Corporation).

[0090] Furthermore, there are no particular problems as long as the particle size of the conductive carbon black is very small relative to the fiber cross-section. The particle size is preferably in the range of 5 to 500 nm, and more preferably in the range of 10 to 50 nm. If the particle size is greater than 500 nm, it will lead to a decrease in fiber strength. If the particle size is less than 5 nm, self-aggregation will occur, resulting in poor dispersibility.

[0091] In this invention, inorganic salts can be introduced into the stock solution. Preferably, the stock solution contains 0 to 20% by mass of inorganic salts, and more preferably 0 to 10% by mass of inorganic salts in order to obtain stable spinning properties.

[0092] If the inorganic salt content exceeds 20% by mass, the solidification rate becomes too fast, creating numerous voids in the fiber, thus preventing the acquisition of fibers with the desired properties. It should be noted that chloride salts such as calcium chloride, magnesium chloride, and lithium chloride are preferred as inorganic salts.

[0093] [Spinning and Coagulation Process]

[0094] In the spinning and solidification process, the above-obtained solution is spun into a solidification solution to solidify. There are no particular limitations on the spinning apparatus; conventional wet spinning apparatus can be used. As long as wet spinning can be performed stably, there are no particular restrictions on the number of spinning holes, the diameter of the spinning holes, or their arrangement. For example, a porous spinning head for short fibers with 10 to 30,000 spinning holes and a diameter of 0.03 to 0.2 mm can be used.

[0095] In addition, the temperature of the dope solution when it is spun out from the spinning head is preferably in the range of 20 to 90°C, and more preferably 70 to 90°C.

[0096] The coagulation bath used to obtain the fibers of the present invention is an aqueous solution containing 1 to 20% by mass of an amide solvent, preferably an aqueous solution containing 3 to 15% by mass of an amide solvent. The temperature of this aqueous solution is preferably in the range of 50 to 90°C. Alternatively, when concentrated sulfuric acid is used as the solvent in the above-described spinning solution preparation process, water can be used as the coagulation bath, and the temperature of the coagulation bath in this case is preferably in the range of 0 to 20°C.

[0097] In addition, when the coagulation bath uses an amide-based solvent, it is preferable that the coagulation bath contains 30% or more by mass, more preferably 35 to 45% by mass of inorganic salts such as calcium chloride or magnesium chloride.

[0098] As described above, the raw solution is spun from the spinning head into the coagulation solution, and then passed through the coagulation bath to obtain coagulated yarn.

[0099] [Cleaning process, boiling water stretching process]

[0100] The obtained coagulated fibers are thoroughly washed with an aqueous cleaning bath and then sent to a boiling water stretching process. The stretching ratio in the boiling water stretching bath should be in the range of 1.1 to 5.0 times, more preferably in the range of 1.1 to 3.0 times. By stretching within this range, the molecular chain orientation is improved, which ensures the strength of the final fiber.

[0101] [Dry heat treatment process]

[0102] The fibers that have undergone the above-described cleaning and stretching processes are preferably subjected to a dry heat treatment process. In the dry heat treatment process, the fibers that have been cleaned in the above-described cleaning process are subjected to dry heat treatment in the range of 100 to 250°C. Preferably, the dry heat treatment is performed in the range of 100 to 200°C. Furthermore, the dry heat treatment is preferably performed at a fixed length. It should be noted that the temperature of the above-described dry heat treatment refers to the set temperature of the fiber heating device such as the hot plate or heating roller.

[0103] [Hot stretching process]

[0104] In this invention, the fibers that have undergone the above-described dry heat treatment process are subjected to a hot stretching process. In the hot stretching process, heat treatment is applied while stretching is performed, within the range of 290–380°C. The preferred treatment temperature is within the range of 290–350°C. Temperatures below 290°C are unsuitable because high-ratio stretching is not possible, and temperatures exceeding 380°C may cause discoloration and fiber breakage. The stretching ratio in the hot stretching process should be within the range of 2.0–10.0 times, preferably within the range of 3.0–10.0 times. It should be noted that the temperature of the hot stretching treatment refers to the set temperature of the fiber heating device such as the hot plate or heating roller.

[0105] It should be noted that the amide-based and sulfuric acid-based systems are generally used in the cleaning process, boiling water stretching process and hot stretching process mentioned above.

[0106] In this invention, the combined stretching ratio of boiling water stretching and hot stretching is generally preferably 5 to 7 times or more. If the combined stretching ratio is less than 5 times, the target strength and / or conductivity may not be fully demonstrated. It should be noted that those skilled in the art can appropriately adjust the boiling water stretching ratio and hot stretching ratio based on the process conditions.

[0107] [Membrane manufacturing methods]

[0108] The heat-resistant and high-toughness membrane of the present invention can be manufactured by the following method: a polymer stock solution containing a copolymer of fully aromatic polyamide obtained by the above-described manufacturing method is added to a solvent such as alcohol or water, then precipitated, separated, and redissolved in a solvent for membrane formation. More preferably, the polymer stock solution is used directly or after polymerization with appropriate concentration adjustment for membrane formation. The concentration adjustment can be performed by concentration or dilution with a solvent. The same solvent exemplified as the polymerization solvent can be used.

[0109] Furthermore, the film is preferably formed by solution film formation. Examples of solution film formation methods include wet-dry methods, dry methods, or wet methods, with wet-dry methods or dry methods being preferred in terms of obtaining films with good surface properties.

[0110] When using a wet membrane fabrication method, it is preferable to extrude the stock solution directly from the spinneret into the membrane-forming bath, or temporarily extrude it onto a support such as a roller, and then introduce it into the wet bath along with the support. This bath is generally composed of an aqueous medium, and may also contain organic solvents, inorganic salts, etc., in addition to water. The wet bath allows for the extraction of salts, organic solvents, etc., contained in the membrane. The overall time spent in these wet baths varies depending on the membrane thickness, and is preferably 10 seconds to 30 minutes.

[0111] In the case of a stretched film, the polymer taken from the wet bath can be stretched along its long side, followed by drying, transverse stretching, and heat treatment. These treatments are generally preferably carried out at 100–500°C for a total of 1 second to 30 minutes.

[0112] In the dry-wet process for film formation, the raw solution is extruded from the spinning head onto a support such as a roller or endless belt to form a thin film. Next, the solvent is dispersed from the film layer, and the film is dried until it exhibits self-holding properties. The drying conditions are preferably room temperature to 300°C for no more than 60 minutes. After the film is peeled from the support at the end of the dry process, it is introduced into the wet process, where desalination and solvent removal are performed in the same manner. In the case of stretched films, further stretching, drying, and heat treatment can be performed.

[0113] In the case of a dry process, the self-retaining film, dried on rollers, endless belts, etc., is peeled off from these supports. In the case of a stretched film, further drying, stretching, and heat treatment can be performed to remove residual solvents. These treatments are preferably carried out at 100–500°C for a total of 1 second to 30 minutes.

[0114] Example

[0115] The present invention will now be described in detail with reference to examples and comparative examples, but the scope of the present invention is not limited to the following examples and comparative examples. It should be noted that the physical property values ​​in the examples and comparative examples were determined by the methods described below.

[0116] [Weight-average molecular weight Mw]

[0117] Based on JIS-K-7252, analysis was performed using a high-performance liquid chromatography (HPLC) apparatus equipped with a size exclusion column. The developing solvent was determined using dimethylformamide (containing 0.01 mol% lithium chloride). It should be noted that Sigma-Aldrich polystyrene kits (peak molecular weight Mp = 400–2,000,000) were used as standard molecular weight samples.

[0118] [Single fiber fineness]

[0119] Based on JIS-L-1015, the determination of fineness according to the A method based on the mass fineness was carried out, and expressed as apparent fineness.

[0120] [Fiber breaking strength, breaking elongation]

[0121] The following tests were conducted using a tensile testing machine (Instron, model 5565) based on JIS-L-1015.

[0122] (Measurement conditions)

[0123] Clip spacing: 20mm

[0124] Initial load: 0.044 cN (1 / 20 g / dtex)

[0125] Stretching speed: 20mm / minute

[0126] [Knot strength]

[0127] The test was performed using a tensile testing machine (Instron, model: 5565) based on JIS-L-1013:2010 Chemical Fiber Filament Test Method 8.6.1 (Standard Time Test).

[0128] [Fiber resistivity]

[0129] The measurements were performed using an SM-8210 superinsulator manufactured by Toa Denpa Kogyo Co., Ltd., in an atmosphere with a relative humidity of 65% RH. The fiber sample length was set to 10 cm (L (cm)), and a voltage of 0.5 kV was applied across this sample length. The resistivity R (Ω) was measured at this point. The cross-sectional area of ​​the conductive wire was set to S (cm²). 2 The density ρ (Ωcm) is calculated from ρ(Ωcm) = R × (S / L). In the embodiments and comparative examples of the present invention, S is considered as the fiber density d = 1.39 g / cm³. 3D, representing the total fineness (dtex) directly converted to mass, is calculated using S = D / (1000000 × d). Furthermore, the number of repeated measurements is 5, and the average value is taken as the resistivity.

[0130] [Dry heat dimensional change rate]

[0131] Based on JIS-L-1013, the dimensional change rate at 250℃ or 300℃ was determined by method B.

[0132] [Melt point of the fiber]

[0133] The melting point of the fiber was determined by thermomechanical analysis based on JIS-K-7197. The melting point was determined by the temperature of the peak detected at high temperatures or the temperature at which peaks could not be detected due to fiber dissolution.

[0134] [Membrane tensile strength and elongation at break]

[0135] The maximum stress during the membrane tensile test was determined using A&D's TENSILON, based on JIS K7127, and the stress and elongation at their maximum values ​​were recorded. The test specimens were 10 mm wide and 50 mm long, and the tensile speed was 20 mm / min.

[0136] [Glass transition temperature and thermal shrinkage of the membrane]

[0137] The softening point and thermal shrinkage rate of the membrane were determined using a thermomechanical analysis apparatus (TMA) manufactured by Hitachi High-Tech Science, based on JIS K 7196 and JIS K 7197.

[0138] [Example 1]

[0139] A copolymeric aromatic polyamide polymer powder, comprising 67 mol% of m-phenylenediamine and isophthaloyl monomer units and 33 mol% of p-phenylenediamine and terephthaloyl monomer units, was synthesized via interfacial polymerization based on Japanese Patent Publication No. 47-10863. In this process, isophthaloyl chloride and terephthaloyl chloride were used as the acyl chloride monomers in a mass ratio of 2:1. Similarly, m-phenylenediamine and p-phenylenediamine were used as the amine monomers in a mass ratio of 2:1. The weight-average molecular weight was 800,000. This polymer powder and calcium chloride were dissolved in N-methyl-2-pyrrolidone (NMP) to obtain a transparent polymer solution. The polymer solution was then adjusted to achieve a copolymeric aromatic polyamide polymer mass concentration of 16% and a calcium chloride mass of 3%.

[0140] The polymer solution was heated to 85°C and used as the spinning solution. It was then sprayed from a spinning head with 100 circular nozzles (0.1 mm in diameter) into an 85°C coagulation bath for spinning. The coagulation bath consisted of 44% calcium chloride, 3% NMP, and 53% water by mass. After passing through the bath with an immersion length (effective coagulation bath length) of 100 cm and a yarn speed of 5.0 m / min, the yarn was temporarily pulled out into the air.

[0141] The solidified filament was washed with water in the first and second water-based cleaning baths for a total immersion time of 200 seconds. It should be noted that the water temperatures for the first and second water-based cleaning baths were 20°C and 30°C, respectively. The filament was then stretched to 2.4 times its original length in boiling water at 90°C, followed by immersion in warm water at 90°C for 40 seconds, and then washed.

[0142] Next, after dry heat treatment on rollers with a surface temperature of 170°C, the fibers are stretched to 4.5 times their original length using a hot plate with a surface temperature of 325°C to obtain fully aromatic polyamide fibers. The resulting fibers have a fineness of 1.3 dtex, a breaking strength of 10.4 cN / dtex, a breaking elongation of 23%, a melting point of 307°C, and a dry heat dimensional change rate of 1.00% at 250°C.

[0143] [Example 2]

[0144] A copolymeric aromatic polyamide polymer powder, comprising 60 mol% of m-phenylenediamine and isophthaloyl monomer units and 40 mol% of p-phenylenediamine and terephthaloyl monomer units, was synthesized via interfacial polymerization based on Example 1. In this process, isophthaloyl chloride and terephthaloyl chloride were used as the acyl chloride monomers in a mass ratio of 3:2. Similarly, m-phenylenediamine and p-phenylenediamine were used as the amine monomers in a mass ratio of 3:2. The weight-average molecular weight was 640,000. This polymer powder and calcium chloride were dissolved in N-methyl-2-pyrrolidone (NMP) to obtain a transparent polymer solution. The polymer solution was then adjusted to achieve a copolymeric aromatic polyamide polymer mass concentration of 16% and a calcium chloride mass of 3%.

[0145] The polymer solution was heated to 85°C and used as the spinning solution. It was then sprayed from a spinning head with 100 circular nozzles (0.1 mm in diameter) into an 85°C coagulation bath for spinning. The coagulation bath consisted of 44% calcium chloride, 3% NMP, and 53% water by mass. After passing through the bath with an immersion length (effective coagulation bath length) of 100 cm and a yarn speed of 5.0 m / min, the yarn was temporarily pulled out into the air.

[0146] The solidified filament was washed with water in two water-based cleaning baths (1 and 2), with a total immersion time of 200 seconds. It should be noted that the water temperatures for the first and second water-based cleaning baths were 20°C and 30°C, respectively. The washed filament was then stretched to 2.5 times its original length in boiling water at 90°C, followed by immersion in warm water at 90°C for 40 seconds, and then washed. Next, it was wound onto rollers with a surface temperature of 170°C for dry heat treatment, and then stretched to 3.5 times its original length using a hot plate with a surface temperature of 330°C to obtain a fully aromatic polyamide fiber. The obtained fiber had a fineness of 1.8 dtex, a breaking strength of 9.2 cN / dtex, a breaking elongation of 22%, a melting point of 319°C, and a dry heat dimensional change rate of 0.70% at 250°C.

[0147] [Example 3]

[0148] A copolymeric aromatic polyamide polymer powder, comprising 56 mol% of m-phenylenediamine and isophthaloyl monomer units and 44 mol% of p-phenylenediamine and terephthaloyl monomer units, was synthesized via interfacial polymerization based on Example 1. In this process, isophthaloyl chloride and terephthaloyl chloride were used as the acyl chloride monomers in a mass ratio of 5:4. Similarly, m-phenylenediamine and p-phenylenediamine were used as the amine monomers in a mass ratio of 5:4. The weight-average molecular weight was 450,000. This polymer powder and calcium chloride were dissolved in N-methyl-2-pyrrolidone (NMP) to obtain a transparent polymer solution. The polymer solution was then adjusted to achieve a copolymeric aromatic polyamide polymer mass concentration of 20% and a calcium chloride mass concentration of 2%.

[0149] The polymer solution was heated to 85°C and used as the spinning solution. It was then sprayed from a spinning head with 100 circular nozzles (0.1 mm in diameter) into an 85°C coagulation bath for spinning. The coagulation bath consisted of 44% calcium chloride, 3% NMP, and 53% water by mass. After passing through the bath with an immersion length (effective coagulation bath length) of 100 cm and a yarn speed of 5.0 m / min, the yarn was temporarily pulled out into the air.

[0150] The solidified filament was washed with water in the first and second water-based cleaning baths for a total immersion time of 200 seconds. It should be noted that the water temperatures for the first and second water-based cleaning baths were 20°C and 30°C, respectively. The filament was then stretched to 2.4 times its original length in boiling water at 90°C, followed by immersion in warm water at 90°C for 40 seconds, and then washed.

[0151] Next, after dry heat treatment on rollers with a surface temperature of 170°C, the fibers are stretched to 4.0 times their original length using a hot plate with a surface temperature of 315°C to obtain fully aromatic polyamide fibers. The resulting fibers have a fineness of 1.54 dtex, a breaking strength of 11.1 cN / dtex, a breaking elongation of 24%, a melting point of 313°C, and a dry heat dimensional change rate of 0.30% at 250°C.

[0152] [Comparative Example 1]

[0153] A copolymeric aromatic polyamide polymer powder, comprising 75 mol% of m-phenylenediamine and isophthaloyl monomer units and 25 mol% of p-phenylenediamine and terephthaloyl monomer units, was synthesized via interfacial polymerization based on Example 1. In this process, isophthaloyl chloride and terephthaloyl chloride were used as the acyl chloride monomers in a mass ratio of 3:1. Similarly, m-phenylenediamine and p-phenylenediamine were used as the amine monomers in a mass ratio of 3:1. The weight-average molecular weight was 610,000. This polymer powder and calcium chloride were dissolved in N-methyl-2-pyrrolidone (NMP) to obtain a transparent polymer solution. The polymer solution was then adjusted to achieve a copolymeric aromatic polyamide polymer mass concentration of 21% and a calcium chloride mass of 3%.

[0154] The polymer solution was spun under the conditions of Example 1 to obtain fully aromatic polyamide fibers. The boiling water stretch ratio was 2.4 times, and the hot plate stretch ratio was 3.0 times. The resulting fibers had a fineness of 1.7 dtex, a breaking strength of 4.6 cN / dtex, an elongation at break of 33%, a melting point of 333°C, and a dry heat dimensional change rate of 0.87% at 250°C.

[0155] [Comparative Example 2]

[0156] A copolymeric aromatic polyamide polymer powder, comprising 33 mol% of m-phenylenediamine and isophthaloyl monomer units and 67 mol% of p-phenylenediamine and terephthaloyl monomer units, was synthesized via interfacial polymerization based on Japanese Patent Publication No. 47-10863. In this process, isophthaloyl chloride and terephthaloyl chloride were used as the acyl chloride monomers in a mass ratio of 1:2. Similarly, m-phenylenediamine and p-phenylenediamine were used as the amine monomers in a mass ratio of 1:2. This polymer did not exhibit good solubility in solvents such as NMP, and therefore could not be spun.

[0157] [Comparative Example 3]

[0158] The physical properties of 100 mol% fully aromatic polyamide fiber (Teijin Corporation's "Conex"), consisting of m-phenylenediamine and isophthaloyl monomer units, were determined. The results showed a fineness of 2.2 dtex, a breaking strength of 4.9 cN / dtex, an elongation at break of 40%, a melting point that could not be determined (above 400°C), and a dry heat dimensional change rate of 0.20% at 250°C.

[0159] [Comparative Example 4]

[0160] The physical properties of a fully aromatic polyamide fiber (manufactured by Teijin Corporation, "Twaron" (registered trademark)) composed of 100 mol% of p-phenylenediamine and terephthaloyl monomer units were determined. The results showed a fineness of 2.0 dtex, a breaking strength of 21 cN / dtex, a breaking elongation of 3%, a melting point that could not be determined (above 400°C), and a dry heat dimensional change rate of 0% at 250°C.

[0161] The physical properties of the fibers obtained in Examples 1-3 and Comparative Examples 1-4 are shown in Table 2.

[0162] [Table 2]

[0163]

[0164] [Example 4]

[0165] A copolymeric aromatic polyamide polymer powder, comprising 67 mol% of m-phenylenediamine and isophthaloyl monomer units and 33 mol% of p-phenylenediamine and terephthaloyl monomer units, was synthesized via interfacial polymerization based on Japanese Patent Publication No. 47-10863. In this process, isophthaloyl chloride and terephthaloyl chloride were used as the acyl chloride monomers in a mass ratio of 2:1. Similarly, m-phenylenediamine and p-phenylenediamine were used as the amine monomers in a mass ratio of 2:1. The weight-average molecular weight was 800,000. This polymer powder and calcium chloride were dissolved in N-methyl-2-pyrrolidone (NMP) to obtain a transparent polymer solution. The polymer solution was then adjusted to achieve a copolymeric aromatic polyamide polymer mass concentration of 16% and a calcium chloride mass of 3%.

[0166] The polymer solution was heated to 85°C and used as the spinning solution. It was then sprayed from a spinning head with 100 circular nozzles (0.1 mm in diameter) into an 85°C coagulation bath for spinning. The coagulation bath consisted of 44% calcium chloride, 3% NMP, and 53% water by mass. After passing through the bath with an immersion length (effective coagulation bath length) of 100 cm and a yarn speed of 5.0 m / min, the yarn was temporarily pulled out into the air.

[0167] The solidified filament was washed with water in the first and second water-based cleaning baths for a total immersion time of 200 seconds. It should be noted that the water temperatures for the first and second water-based cleaning baths were 20°C and 30°C, respectively. The filament was then stretched to 2.4 times its original length in boiling water at 90°C, followed by immersion in warm water at 90°C for 40 seconds, and then washed.

[0168] Next, after dry heat treatment on rollers with a surface temperature of 170°C, the fibers are stretched to 4.5 times their original length using a hot plate with a surface temperature of 325°C to obtain fully aromatic polyamide fibers. The resulting fibers have a weight-average molecular weight of 800,000, a fineness of 1.3 dtex, a breaking strength of 10.4 cN / dtex, a knot strength of 4.4 cN / dtex, an elongation at break of 23%, a melting point of 307°C, and a dry heat dimensional change rate of 1.00% at 250°C.

[0169] [Example 5]

[0170] A copolymeric aromatic polyamide polymer powder, comprising 56 mol% of m-phenylenediamine and isophthaloyl monomer units and 44 mol% of p-phenylenediamine and terephthaloyl monomer units, was synthesized via interfacial polymerization based on Japanese Patent Publication No. 47-10863. In this process, isophthaloyl chloride and terephthaloyl chloride were used as the acyl chloride monomers in a mass ratio of 5:4. Similarly, m-phenylenediamine and p-phenylenediamine were used as the amine monomers in a mass ratio of 5:4. The weight-average molecular weight was 450,000. This polymer powder and calcium chloride were dissolved in N-methyl-2-pyrrolidone (NMP) to obtain a transparent polymer solution. The polymer solution was then adjusted to achieve a copolymeric aromatic polyamide polymer mass concentration of 20% and a calcium chloride mass concentration of 2%.

[0171] The polymer solution was heated to 85°C and used as the spinning solution. It was then sprayed from a spinning head with 100 circular nozzles (0.1 mm in diameter) into an 85°C coagulation bath for spinning. The coagulation bath consisted of 44% calcium chloride, 3% NMP, and 53% water by mass. After passing through the bath with an immersion length (effective coagulation bath length) of 100 cm and a yarn speed of 5.0 m / min, the yarn was temporarily pulled out into the air.

[0172] The solidified filament was washed with water in the first and second water-based cleaning baths for a total immersion time of 200 seconds. It should be noted that the water temperatures for the first and second water-based cleaning baths were 20°C and 30°C, respectively. The filament was then stretched to 2.4 times its original length in boiling water at 90°C, followed by immersion in warm water at 90°C for 40 seconds, and then washed.

[0173] Next, after dry heat treatment on rollers with a surface temperature of 170°C, the fibers are stretched to 4.0 times their original length using a hot plate with a surface temperature of 315°C to obtain fully aromatic polyamide fibers. The resulting fibers have a weight-average molecular weight of 450,000, a fineness of 1.54 dtex, a breaking strength of 11.1 cN / dtex, a knot strength of 4.9 cN / dtex (45%), an elongation at break of 24%, a melting point of 313°C, and a dry heat dimensional change rate of 0.30% at 250°C.

[0174] [Example 6]

[0175] A copolymeric aromatic polyamide polymer powder, comprising 50 mol% of m-phenylenediamine and isophthaloyl monomer units and 50 mol% of p-phenylenediamine and terephthaloyl monomer units, was synthesized via interfacial polymerization based on Japanese Patent Publication No. 47-10863. In this process, isophthaloyl chloride and terephthaloyl chloride were used as the acyl chloride monomers in a 1:1 mass ratio. Similarly, m-phenylenediamine and p-phenylenediamine were used as the amine monomers in a 1:1 mass ratio. The weight-average molecular weight was 640,000. This polymer powder and calcium chloride were dissolved in N-methyl-2-pyrrolidone (NMP) to obtain a transparent polymer solution. The polymer solution was then adjusted to achieve a copolymeric aromatic polyamide polymer mass concentration of 16% and a calcium chloride mass of 3%.

[0176] The polymer solution was heated to 85°C and used as the spinning solution. It was then sprayed from a spinning head with 100 circular nozzles (0.1 mm in diameter) into an 85°C coagulation bath for spinning. The coagulation bath consisted of 44% calcium chloride, 3% NMP, and 53% water by mass. After passing through the bath with an immersion length (effective coagulation bath length) of 100 cm and a yarn speed of 5.0 m / min, the yarn was temporarily pulled out into the air.

[0177] The solidified filament was washed with water in the first and second water-based cleaning baths, with a total immersion time of 200 seconds. It should be noted that the water temperatures for the first and second water-based cleaning baths were 20°C and 30°C, respectively. The filament was then stretched to 2.5 times its original length in boiling water at 90°C, followed by immersion in warm water at 90°C for 40 seconds, and then washed.

[0178] Next, after dry heat treatment on rollers with a surface temperature of 170°C, the fibers were stretched to 3.5 times their original length using a hot plate with a surface temperature of 330°C to obtain fully aromatic polyamide fibers. The resulting fibers had a weight-average molecular weight of 640,000, a fineness of 1.8 dtex, a breaking strength of 11.8 cN / dtex, a knot strength of 5.6 cN / dtex (48%), an elongation at break of 22%, a melting point of 301°C, and a dry heat dimensional change rate of 0.70% at 250°C.

[0179] [Comparative Example 5]

[0180] The physical properties of a 100 mol% fully aromatic copolyamide fiber (manufactured by Teijin Corporation, "Technora"), consisting of p-phenylenediamine and terephthaloyl monomer units as a whole, were determined. The results showed a fineness of 1.67 dtex, a breaking strength of 26.96 cN / dtex, a knot strength of 4.6 cN / dtex (16.9%), an elongation at break of 6.1%, a melting point of over 500°C, and a dry heat dimensional change rate of 0.30% at 280°C.

[0181] [Comparative Example 6]

[0182] A copolymeric aromatic polyamide polymer powder, comprising 33 mol% of m-phenylenediamine and isophthaloyl monomer units and 67 mol% of p-phenylenediamine and terephthaloyl monomer units, was synthesized via interfacial polymerization based on Japanese Patent Publication No. 47-10863. In this process, isophthaloyl chloride and terephthaloyl chloride were used as the acyl chloride monomers in a mass ratio of 1:2. Similarly, m-phenylenediamine and p-phenylenediamine were used as the amine monomers in a mass ratio of 1:2. This polymer did not exhibit good solubility in solvents such as NMP and could not be spun.

[0183] [Comparative Example 7]

[0184] A polymer solution of 100 mol% of fully aromatic polyamide fiber (manufactured by Teijin Corporation, "Twaron"), consisting entirely of p-phenylenediamine and terephthaloyl monomer units, was mixed with a polymer solution of 100 mol% of fully aromatic polyamide fiber (manufactured by Teijin Corporation, "Conex"), consisting entirely of m-phenylenediamine and isophthaloyl monomer units, at a mass ratio of 5:95. This polymer solution was spun under the conditions of Example 4 to obtain fully aromatic polyamide fiber. The physical properties of the obtained fiber were measured, and the results showed a fineness of 1.8 dtex, a breaking strength of 22.4 cN / dtex, a knot strength of 3.7 cN / dtex (16.5%), an elongation at break of 4.6%, a melting point that could not be determined (above 400°C), and a dry heat dimensional change rate of 0% at 250°C.

[0185] The physical properties of the fibers obtained in Examples 4-6 and Comparative Examples 5-7 are shown in Table 3.

[0186] [Table 3]

[0187]

[0188] [Example 7]

[0189] After dissolving the amine monomer in NMP, the solution was cooled to 0°C, and the acyl chloride monomer was added while stirring with a mechanical stirrer. At this point, the overall solution composition was adjusted to 29 mol% of p-m-phenylenediamine units and 71 mol% of p-phenylenediamine and terephthalamide monomer units, resulting in a polymer mass concentration of 10.7%. Furthermore, terephthaloyl chloride was used as the acyl chloride monomer, and both m-phenylenediamine and p-phenylenediamine were used as the amine monomers, with a mass ratio of 4:3. After confirming that the increase in viscosity and solution temperature had stalled during polymerization, an equal amount of calcium hydroxide was added, and the mixture was stirred until it became transparent, thus preparing a polymer solution containing a copolymerized aromatic polyamide. The weight-average molecular weight was 690,000.

[0190] The polymer solution was heated to 85°C and used as the spinning solution. It was then sprayed from a spinning head with 100 circular nozzles (0.1 mm in diameter) into a coagulation bath at 85°C for spinning. The coagulation bath consisted of 43% calcium chloride, 10% NMP, and 47% water by mass. After passing through the bath with an immersion length (effective coagulation bath length) of 100 cm and a filament speed of 5.0 m / min, the filaments were temporarily pulled into the air to obtain coagulated filaments.

[0191] The solidified filament was washed with water in the first and second water-based cleaning baths for a total immersion time of 200 seconds. It should be noted that the water temperatures for the first and second water-based cleaning baths were 20°C and 30°C, respectively. The filament was then stretched to 2.0 times its original size in boiling water at 90°C, followed by immersion in warm water at 90°C for 40 seconds, and then washed.

[0192] Next, after dry heat treatment on rollers with a surface temperature of 170°C, the fibers are stretched to 2.2 times their original size using a hot plate with a surface temperature of 335°C to obtain fully aromatic polyamide fibers. The resulting fibers have a fineness of 1.3 dtex, a breaking strength of 10.5 cN / dtex, a breaking elongation of 15.0%, and a dimensional change rate of 2.0% under dry heat treatment at 300°C.

[0193] [Example 8]

[0194] A polymer solution containing 33 mol% m-phenylenediamine units and 67 mol% p-phenylenediamine and terephthaloyl monomer units was synthesized via solution polymerization based on Example 7. In this case, terephthaloyl chloride was used as the acyl chloride monomer. Additionally, m-phenylenediamine and p-phenylenediamine were used as the amine monomers in a mass ratio of 2:1. The weight-average molecular weight was 620,000. This polymer solution was heated to 85°C and used as a spinning solution. The solution was then spun from a spinning head with 100 circular orifices (0.1 mm diameter) into an 85°C coagulation bath. The coagulation bath consisted of 45% calcium chloride, 12% NMP, and 43% water. After passing through the bath at an immersion length (effective coagulation bath length) of 100 cm and a filament speed of 5.0 m / min, the filament was temporarily pulled into the air to obtain a coagulated filament.

[0195] The solidified filament was washed with water in the first and second water-based cleaning baths for a total immersion time of 200 seconds. It should be noted that the water temperatures for the first and second water-based cleaning baths were 20°C and 30°C, respectively. The filament was then stretched to 2.0 times its original size in boiling water at 90°C, followed by immersion in warm water at 90°C for 40 seconds, and then washed.

[0196] Next, after dry heat treatment on rollers with a surface temperature of 170°C, the fiber is stretched to 2.0 times its original size using a hot plate with a surface temperature of 325°C to obtain a fully aromatic polyamide fiber. The resulting fiber has a fineness of 1.5 dtex, a breaking strength of 10.6 cN / dtex, a breaking elongation of 13.0%, and a dimensional change rate of 2.1% after dry heat treatment at 300°C.

[0197] [Example 9]

[0198] A polymer solution containing 25 mol% m-phenylenediamine units and 75 mol% p-phenylenediamine and terephthaloyl monomer units was synthesized via solution polymerization based on Example 7. In this case, terephthaloyl chloride was used as the acyl chloride monomer. Additionally, m-phenylenediamine and p-phenylenediamine were used as the amine monomers in a 1:1 mass ratio. The weight-average molecular weight was 580,000. This polymer solution was heated to 85°C and used as a spinning solution. It was then spun from a spinning head with 100 circular nozzles (0.1 mm diameter) into an 85°C coagulation bath. The coagulation bath consisted of 40% calcium chloride, 10% NMP, and 50% water. After passing through the coagulation bath at an immersion length (effective coagulation bath length) of 100 cm and a yarn speed of 5.0 m / min, the yarn was temporarily pulled out into the air.

[0199] The solidified filament was washed with water in the first and second water-based cleaning baths, with a total immersion time of 200 seconds. It should be noted that the water temperatures for the first and second water-based cleaning baths were 20°C and 30°C, respectively. The filament was then stretched to 2.3 times its original length in boiling water at 90°C, followed by immersion in warm water at 90°C for 40 seconds, and then washed.

[0200] Next, after dry heat treatment on rollers with a surface temperature of 170°C, the fibers are stretched to 1.5 times their original size using a hot plate with a surface temperature of 325°C to obtain fully aromatic polyamide fibers. The resulting fibers have a fineness of 1.5 dtex, a breaking strength of 12.0 cN / dtex, a breaking elongation of 13.0%, and a dimensional change rate of 1.9% after dry heat treatment at 300°C.

[0201] [Comparative Example 8]

[0202] A polymer solution containing 66 mol% m-phenylenediamine units and 34 mol% p-phenylenediamine and terephthaloyl monomer units was synthesized via solution polymerization based on Example 7. In this case, isophthaloyl chloride and terephthaloyl chloride were used as the acyl chloride monomers in a mass ratio of 1:2. Additionally, m-phenylenediamine was used as the amine monomer. The weight-average molecular weight was 580,000. This polymer solution was heated to 85°C and used as a spinning solution. It was then spun from a spinning head with 100 circular nozzles (0.1 mm diameter) into an 85°C coagulation bath. The coagulation bath consisted of 40% calcium chloride by mass, 10% NMP by mass, and the remainder water by mass. After passing through the coagulation bath at an immersion length (effective coagulation bath length) of 100 cm and a yarn speed of 5.0 m / min, the yarn was temporarily pulled out into the air.

[0203] The solidified filament was washed with water in the first and second water-based cleaning baths, with a total immersion time of 200 seconds. It should be noted that the water temperatures for the first and second water-based cleaning baths were 20°C and 30°C, respectively. The filament was then stretched to 2.3 times its original length in boiling water at 90°C, followed by immersion in warm water at 90°C for 40 seconds, and then washed.

[0204] Next, after dry heat treatment on rollers with a surface temperature of 170°C, the fiber is stretched to 2.0 times its original size using a hot plate with a surface temperature of 325°C to obtain a fully aromatic polyamide fiber. The resulting fiber has a fineness of 2.0 dtex, a breaking strength of 6.3 cN / dtex, a breaking elongation of 12.0%, and a dimensional change rate of 15% under dry heat treatment at 300°C.

[0205] [Comparative Example 9]

[0206] A polymer solution containing a copolymerized aromatic polyamide polymer of 9 mol% m-phenylenediamine units and 91 mol% p-phenylenediamine and terephthaloyl monomer units was synthesized by solution polymerization based on Example 7. In this case, terephthaloyl chloride was used as the acyl chloride monomer. Additionally, m-phenylenediamine and p-phenylenediamine were used as the amine monomers, with a mass ratio of 6:14. As polymerization proceeded, the solubility of the polymer decreased, exhibiting no solubility in solvents such as NMP, thus preventing spinning.

[0207] [Comparative Example 10]

[0208] The physical properties of 100 mol% of fully aromatic polyamide fiber ("Conex" manufactured by Teijin Corporation, a registered trademark) consisting of m-phenylenediamine and isophthaloyl monomer units were determined. The results showed a fineness of 2.2 dtex, a breaking strength of 4.8 cN / dtex, an elongation at break of 39.0%, and a dry heat dimensional change rate of 5.0% at 300°C.

[0209] [Comparative Example 11]

[0210] The physical properties of a fully aromatic polyamide fiber (manufactured by Teijin Corporation, "Twaron" (registered trademark)) composed of 100 mol% of p-phenylenediamine and terephthaloyl monomer units were measured. The results showed a fineness of 2.0 dtex, a breaking strength of 22 cN / dtex, an elongation at break of 2.5%, and a dry heat dimensional change of 0% at 300°C. Since the elongation at break of this fiber is less than 5.0%, its high toughness is not fully realized.

[0211] The physical properties of the fibers obtained in Examples 7-9 and Comparative Examples 8-11 are shown in Table 4.

[0212] [Table 4]

[0213]

[0214] [Example 10]

[0215] A copolymerized aromatic polyamide polymer powder, comprising 67 mol% of m-phenylenediamine and isophthaloyl monomer units and 33 mol% of p-phenylenediamine and terephthaloyl monomer units, was synthesized via interfacial polymerization based on Japanese Patent Publication No. 47-10863. In this process, isophthaloyl chloride and terephthaloyl chloride were used as the acyl chloride monomers in a mass ratio of 2:1. Similarly, m-phenylenediamine and p-phenylenediamine were used as the amine monomers in a mass ratio of 2:1. The weight-average molecular weight was 660,000. This polymer powder was then mixed with conductive carbon black particles (with a surface resistivity of 10 Ω·cm). 4 Ω) is dissolved and dispersed in N-methyl-2-pyrrolidone (NMP) to obtain a polymer solution. At this point, the polymer solution is adjusted to achieve a copolymerized aromatic polyamide polymer concentration of 16% by mass, and the aromatic polyamide polymer is adjusted to achieve a conductive carbon black concentration of 30% by mass.

[0216] The polymer solution was heated to 85°C and used as the spinning solution. It was then sprayed from a spinning head with 100 circular nozzles (0.1 mm in diameter) into an 85°C coagulation bath for spinning. The coagulation bath consisted of 43% calcium chloride, 4% NMP, and 53% water by mass. After passing through the bath with an immersion length (effective coagulation bath length) of 100 cm and a yarn speed of 5.0 m / min, the yarn was temporarily pulled out into the air.

[0217] The solidified filament was washed with water in the first and second water-based cleaning baths for a total immersion time of 200 seconds. It should be noted that the water temperatures for the first and second water-based cleaning baths were 20°C and 30°C, respectively. The filament was then stretched to 1.4 times its original length in boiling water at 90°C, followed by immersion in warm water at 90°C for 40 seconds, and then washed.

[0218] Next, after dry heat treatment on a roller with a surface temperature of 170°C, the fiber is stretched to 5.7 times its original length using a hot plate with a surface temperature of 325°C to obtain a fully aromatic polyamide fiber. The resulting fiber has a fineness of 2.0 dtex, a breaking strength of 4.9 cN / dtex, a breaking elongation of 14%, a melting point of 301°C, and a resistivity of 61.1 Ωcm.

[0219] [Example 11]

[0220] A copolymerized aromatic polyamide polymer powder, comprising 60 mol% of m-phenylenediamine and isophthaloyl monomer units and 40 mol% of p-phenylenediamine and terephthaloyl monomer units, was synthesized via interfacial polymerization based on Japanese Patent Publication No. 47-10863. In this process, isophthaloyl chloride and terephthaloyl chloride were used as the acyl chloride monomers in a mass ratio of 3:2. Similarly, m-phenylenediamine and p-phenylenediamine were used as the amine monomers in a mass ratio of 3:2. The weight-average molecular weight was 650,000. This polymer powder was then mixed with conductive carbon black particles (with a surface resistivity of 10 Ω·cm). 4 Ω) is dissolved and dispersed in N-methyl-2-pyrrolidone (NMP) to obtain a polymer solution. At this point, the polymer solution is adjusted to achieve a copolymerized aromatic polyamide polymer mass concentration of 18%, and the aromatic polyamide polymer is adjusted to achieve a conductive carbon black content of 25%.

[0221] The polymer solution was heated to 85°C and used as the spinning solution. It was then sprayed from a spinning head with 100 circular nozzles (0.1 mm in diameter) into a coagulation bath at 88°C for spinning. The coagulation bath consisted of 44% calcium chloride, 2% NMP, and 54% water by mass. After passing through the coagulation bath at an immersion length (effective coagulation bath length) of 100 cm and a yarn speed of 5.0 m / min, the yarn was temporarily pulled out into the air.

[0222] The solidified filament was washed with water in the first and second water-based cleaning baths for a total immersion time of 200 seconds. It should be noted that the water temperatures for the first and second water-based cleaning baths were 20°C and 30°C, respectively. The washed filament was then stretched to 2.5 times its original length in boiling water at 90°C, followed by immersion in warm water at 90°C for 40 seconds, and then washed. Next, it was wound onto rollers with a surface temperature of 170°C for dry heat treatment, and then stretched to 4 times its original length using a hot plate with a surface temperature of 330°C to obtain a fully aromatic polyamide fiber. The obtained fiber had a fineness of 1.7 dtex, a breaking strength of 5.2 cN / dtex, a breaking elongation of 16%, a melting point of 306°C, and a resistivity of 171 Ωcm.

[0223] [Comparative Example 12]

[0224] A copolymerized aromatic polyamide polymer powder, comprising 75 mol% of m-phenylenediamine and isophthaloyl monomer units and 25 mol% of p-phenylenediamine and terephthaloyl monomer units, was synthesized via interfacial polymerization based on Japanese Patent Publication No. 47-10863. In this process, isophthaloyl chloride and terephthaloyl chloride were used as the acyl chloride monomers in a mass ratio of 3:1. Similarly, m-phenylenediamine and p-phenylenediamine were used as the amine monomers in a mass ratio of 3:1. The weight-average molecular weight was 700,000. This polymer powder was then mixed with conductive carbon black particles (with a surface resistivity of 10 Ω·cm). 4 Ω) is dissolved and dispersed in N-methyl-2-pyrrolidone (NMP) to obtain a polymer solution. At this point, the polymer solution is adjusted to achieve a copolymerized aromatic polyamide polymer mass concentration of 18%, and the aromatic polyamide polymer is adjusted to achieve a conductive carbon black content of 25%.

[0225] The polymer solution was spun under the conditions of Example 10 to obtain fully aromatic polyamide fibers. At this point, the boiling water stretch ratio of 3.0 times and the hot plate stretch ratio of 1.3 times were the limits; if these ratios were increased, fiber breakage occurred. The obtained fibers had a fineness of 1.9 dtex, a breaking strength of 4.9 cN / dtex, a breaking elongation of 17%, and a melting point of 340°C. As mentioned above, since the total stretch ratio could not be sufficiently obtained, the resistivity was 7.98 × 10⁻⁶. 6 Such a high value as Ωcm.

[0226] [Comparative Example 13]

[0227] A copolymeric aromatic polyamide polymer powder, comprising 33 mol% of m-phenylenediamine and isophthaloyl monomer units and 64 mol% of p-phenylenediamine and terephthaloyl monomer units, was synthesized via interfacial polymerization based on Japanese Patent Publication No. 47-10863. In this process, isophthaloyl chloride and terephthaloyl chloride were used as the acyl chloride monomers in a mass ratio of 1:2. Similarly, m-phenylenediamine and p-phenylenediamine were used as the amine monomers in a mass ratio of 1:2. This polymer did not exhibit good solubility in solvents such as NMP, and therefore could not be spun.

[0228] [Comparative Example 14]

[0229] A copolymerized aromatic polyamide polymer powder was synthesized, comprising 67 mol% of m-phenylenediamine and isophthaloyl monomer units and 33 mol% of p-phenylenediamine and terephthaloyl monomer units. In this process, isophthaloyl chloride and terephthaloyl chloride were used as the acyl chloride monomers in a 2:1 mass ratio. Similarly, m-phenylenediamine and p-phenylenediamine were used as the amine monomers in a 2:1 mass ratio. The weight-average molecular weight was 590,000. This polymer powder was then mixed with conductive carbon black particles (with a surface resistivity of 10 Ω·cm). 4Ω) is dissolved and dispersed in N-methyl-2-pyrrolidone (NMP) to obtain a polymer solution. At this point, the polymer solution is adjusted to achieve a copolymerized aromatic polyamide polymer mass concentration of 21%, and the aromatic polyamide polymer is adjusted to achieve a conductive carbon black content of 5%.

[0230] The polymer solution was spun under the conditions of Example 10 to obtain fully aromatic polyamide fibers. The boiling water stretch ratio was 2.5 times, and the hot plate stretch ratio was 3.2 times. The resulting fibers had a fineness of 1.7 dtex, a breaking strength of 6.4 cN / dtex, a breaking elongation of 21%, a melting point of 304°C, and a resistivity of 2.69 × 10⁻⁶. 6 Ωcm.

[0231] [Comparative Example 15]

[0232] A copolymerized aromatic polyamide polymer powder was synthesized, comprising 67 mol% of m-phenylenediamine and isophthaloyl monomer units and 33 mol% of p-phenylenediamine and terephthaloyl monomer units. In this process, isophthaloyl chloride and terephthaloyl chloride were used as the acyl chloride monomers in a mass ratio of 2:1. Similarly, m-phenylenediamine and p-phenylenediamine were used as the amine monomers in a mass ratio of 2:1. The weight-average molecular weight was 660,000. This polymer powder was then mixed with conductive carbon black particles (with a surface resistivity of 10 Ω·cm). 4 Ω) is dissolved and dispersed in N-methyl-2-pyrrolidone (NMP) to obtain a polymer solution. At this point, the polymer solution is adjusted to achieve a copolymerized aromatic polyamide polymer mass concentration of 16%, and the aromatic polyamide polymer is adjusted to achieve a conductive carbon black content of 45%.

[0233] The polymer solution was spun under the conditions of Example 10 to obtain fully aromatic polyamide fibers. At this point, the boiling water stretching ratio of 1.1 times and the hot plate stretching ratio of 2.5 times were the limits; if these ratios were increased, fiber breakage occurred. The obtained fibers had a fineness of 7.0 dtex, a breaking strength of 1.9 cN / dtex, a breaking elongation of 13%, a melting point of 313°C, and a resistivity of 8.5 Ωcm.

[0234] The physical properties of the fibers obtained in Examples 10-11 and Comparative Examples 12-15 are shown in Table 5.

[0235] [Table 5]

[0236]

[0237] [Example 12]

[0238] A copolymeric aromatic polyamide polymer powder, comprising 56 mol% isophthaloyl-m-phenylenediamine units and 44 mol% p-phenylenediamine terephthaloyldiamine units, was synthesized via interfacial polymerization based on Japanese Patent Publication No. 47-10863. In this process, isophthaloyl chloride and p-phenylenediamine were used as the acyl chloride monomers in a mass ratio of 5:4. Similarly, m-phenylenediamine and p-phenylenediamine were used as the amine monomers in a mass ratio of 5:4. The weight-average molecular weight was 470,000. The polymer powder was dissolved in 99.8% sulfuric acid to obtain a transparent polymer solution. The polymer solution was then adjusted to achieve a mass concentration of 18% for the copolymeric aromatic polyamide polymer.

[0239] The polymer solution was heated to 60°C and used as the spinning solution. It was then sprayed from a circular spinning head with 100 orifices (0.08 mm diameter) heated to 70°C through an 8 mm air gap into water at 5°C for spinning. In this coagulation process, after passing through the water at an immersion length (effective coagulation bath length) of 5 cm and a yarn speed of 30 m / min, the yarn was temporarily pulled out into the air.

[0240] The solidified filament was washed with water in the first to third water-based cleaning baths, with a total immersion time of 30 seconds. It should be noted that the water temperatures for the first to third water-based cleaning baths were 20°C, 30°C, and 60°C, respectively. The cleaned filament was then stretched to 1.2 times its original length in boiling water at 90°C.

[0241] Next, after dry heat treatment on rollers with a surface temperature of 180°C, the fibers are stretched to 6.5 times their original length using a hot plate with a surface temperature of 315°C to obtain fully aromatic polyamide fibers. The resulting fibers have a fineness of 1.2 dtex, a breaking strength of 10.1 cN / dtex, a breaking elongation of 19%, a melting point of 310°C, and a dry heat dimensional change rate of 0.5% at 250°C.

[0242] [Example 13]

[0243] A polymer solution containing 50 mol% of m-phenylenediamine units and 50 mol% of terephthaloyl monomer units was synthesized via solution polymerization based on Example 7. In this case, terephthaloyl chloride was used as the acyl chloride monomer, and m-phenylenediamine was used as the amine monomer. The weight-average molecular weight was 560,000. The polymer solution was placed on a glass plate and thinned using a doctor blade method. Next, it was dried at 100°C for 5 minutes and then placed in a water bath to remove the solvent. Subsequently, it was dried at 100°C for 30 minutes to obtain a fully aromatic polyamide film. The resulting film had a thickness of 15 μm, a tensile strength of 130 MPa, an elongation at break of 17.0%, a glass transition temperature of 320°C, and a dry heat dimensional change rate of 0.5% at 300°C.

[0244] [Example 14]

[0245] A polymer solution containing a copolymer of aromatic polyamide, comprising 25 mol% m-phenylenediamine units and 75 mol% p-phenylenediamine and terephthaloyl monomer units, was synthesized via solution polymerization based on Example 7. In this case, terephthaloyl chloride was used as the acyl chloride monomer. Additionally, m-phenylenediamine and p-phenylenediamine were used as the amine monomers in a 1:1 mass ratio. The weight-average molecular weight was 580,000. This polymer solution was then used to prepare a copolymer aromatic polyamide film using the same method as in Example 13. The resulting film had a thickness of 15 μm, a tensile strength of 120 MPa, an elongation at break of 6.0%, a glass transition temperature of 280 °C, and a dry heat dimensional change rate of 3.0% at 300 °C.

[0246] [Comparative Example 16]

[0247] The polymer solution synthesized in Comparative Example 8 was used to prepare a copolymerized aromatic polyamide film using the same method as in Example 13. The resulting film had a thickness of 15 μm, a tensile strength of 50 MPa, an elongation at break of 13%, a glass transition temperature of 260 °C, and a dry heat dimensional change rate of 5.8% at 300 °C.

[0248] Industrial availability

[0249] The heat-resistant, high-toughness fiber of the present invention has an excellent balance of strength, elongation, and heat resistance, making it suitable for applications where general-purpose fibers are used at the expense of heat resistance, and for applications where mechanical properties are supplemented by combining multiple fibers. Furthermore, in reinforcing material applications, it is suitable for novel heat-resistant, high-toughness materials that combine appropriate strength and flexibility, such as materials in the field of rubber reinforcement where strength is required despite significant deformation. In addition, in fall protection material applications, it is suitable for novel heat-resistant, high-toughness materials that combine appropriate strength and flexibility, such as materials for safety ropes where strength is required despite significant deformation. Furthermore, according to the present invention, conductivity can be imparted; even in high-temperature environments, the fibers of the present invention can maintain high conductivity and electrostatic properties, making them useful not only as protective clothing materials but also as reinforcing fibers for resin structural materials and the like that require electrostatic properties and are exposed to high-temperature environments. Moreover, the heat-resistant, high-toughness film of the present invention has an excellent balance of strength, elongation, glass transition temperature, and thermal shrinkage, making it particularly useful in applications where strength and elongation are required in high-temperature regions.

Claims

1. A heat-resistant and high-toughness fiber, characterized in that, It is a heat-resistant and high-toughness fiber containing monomer units selected from m-phenylenediamine, p-phenylenediamine, isophthalamide, and terephthalamide. The combination of the individual units is any one of the following combinations: The three monomer units are m-phenylenediamine, isophthaloyl, and terephthaloyl. The three monomer units are m-phenylenediamine, p-phenylenediamine, and isophthalamide. The three monomer units are m-phenylenediamine, p-phenylenediamine, and terephthalamide. The four monomer units are m-phenylenediamine, p-phenylenediamine, isophthaloyl, and terephthaloyl. The two monomer units are m-phenylenediamine and terephthaloyl. The heat-resistant and high-toughness fiber has a weight-average molecular weight of 400,000 to 1,000,000, a breaking strength of 3.5 to 15 cN / dtex, a breaking elongation of 5 to 30%, and a melting point above 290°C. The heat-resistant and high-toughness fiber also meets any one of the following requirements (1) to (3): (1) The tensile strength is 7-15 cN / dtex, the elongation at break is 10-30%, and the dry heat dimensional change rate at 250°C is less than 2%, and the molar ratio of the m-phenylenediamine and / or the isophthaloyl monomer unit to the p-phenylenediamine and / or the terephthaloyl monomer unit is in the range of 40 or more and less than 70:60 and greater than 30; (2) The tensile strength is 8.0 cN / dtex or higher and less than 15.0 cN / dtex, the elongation at break is greater than 5.0% and less than 20.0%, and the dry heat dimensional change rate at 300°C is less than 5%. The molar ratio of the m-phenylenediamine and / or the isophthaloyl monomer unit to the p-phenylenediamine and / or the terephthaloyl monomer unit is 10 or higher and less than 40:90 and greater than 60, excluding cases where the monomer unit combination is the four monomer units of m-phenylenediamine, p-phenylenediamine, isophthaloyl, and terephthaloyl; or (3) The fiber contains 6-40% by mass of conductive particles with a resistivity of 10. 3 The strength is below Ωcm, and the tensile strength is 3.5 to 10 cN / dtex, wherein the molar ratio of the m-phenylenediamine and / or the isophthaloyl monomer unit to the p-phenylenediamine and / or the terephthaloyl monomer unit is in the range of 50 or more and less than 70:50 and greater than 30.

2. The heat-resistant and high-toughness fiber according to claim 1, wherein, The heat-resistant and high-toughness fiber is a copolymerized aromatic polyamide polymer containing at least three monomer units selected from m-phenylenediamine, p-phenylenediamine, isophthalamide, and terephthalamide.

3. The heat-resistant and high-toughness fiber according to claim 1, wherein, The knot strength is further 4.4–5.6 cN / dtex.

4. The heat-resistant and high-toughness fiber according to claim 1, wherein, The conductive particles are conductive carbon black.

5. The method for manufacturing the heat-resistant and high-toughness fiber according to claim 1, characterized in that, Including the following processes (1) to (6): (1) Prepare a copolymerized aromatic polyamide polymer containing at least three monomer units selected from m-phenylenediamine, p-phenylenediamine, isophthaloyl, and terephthaloyl. The combination of the individual units is any one of the following combinations: The three monomer units are m-phenylenediamine, isophthaloyl, and terephthaloyl. The three monomer units are m-phenylenediamine, p-phenylenediamine, and isophthalamide. The three monomer units are m-phenylenediamine, p-phenylenediamine, and terephthalamide, or The four monomer units are m-phenylenediamine, p-phenylenediamine, isophthaloyl, and terephthaloyl. The molar ratio of the m-phenylenediamine and / or the isophthaloyl monomer unit to the p-phenylenediamine and / or the terephthaloyl monomer unit is in the range of 10 or more and less than 70:90 and greater than 30, and the weight-average molecular weight is 400,000 to 1,000,000. (2) Dissolve the copolymerized aromatic polyamide polymer in a solvent to prepare a spinning solution. (3) The spinning solution is passed through the spinning head and spun into a coagulation bath to obtain coagulated yarn. (4) The coagulated filament is washed with water-based cleaning solution, and then stretched in a boiling water stretching bath at a ratio of 1.1 to 5.0 times to obtain the fiber. (5) The fiber was subjected to dry heat treatment in the range of 100–250°C, and then, (6) While applying heat treatment to the dry heat-treated fiber in the range of 290 to 380°C, hot stretching is performed in the range of 2.0 to 10.0 times the stretch ratio.

6. The manufacturing method according to claim 5, wherein, The spinning solution is prepared by dissolving the copolymerized aromatic polyamide polymer in an amide solvent at a concentration of 5-30% by mass, and the coagulation bath contains 1-20% by mass of the amide solvent.

7. The manufacturing method according to claim 5, wherein, The spinning solution is prepared by dissolving the copolymerized aromatic polyamide polymer in concentrated sulfuric acid with a concentration of 95% or higher at a mass range of 5-30%, and the coagulation bath contains water.

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