Fibers made from polyamide resin composition

Abstract

The polyamide resin composition is obtained by the polymerization of a diamine component and sebacic acid, wherein the terminal amino group content is 5.0 × 10-5 to 10.0 × 10-5 mol / g and the value provided by subtracting the terminal carboxyl group content from the terminal amino group content is 1.0 × 10-5 to 6.5 × 10-5 mol / g.　The resulting polyamide composition exhibits an excellent polymer color, an excellent dyeability, and an excellent spinning workability.

Description

[Technical Field]

[0001] The present invention relates to a polyamide resin composition obtained by polycondensation of a diamine component and sebaciic acid, which has excellent dyeability and spinning operability. [Background technology]

[0002] Thermoplastic resins such as polyamides and polyesters are widely used in clothing fibers, industrial fibers, and resin molding applications, and they offer excellent strength, durability, heat resistance, stretchability, and colorfastness. Furthermore, when using polyamides in textile applications, there is a demand for polyamides with excellent color development to achieve vibrant colors. In recent years, with growing concern for environmental protection, there has also been a demand for polyamides with low wastewater discharge from dyes and excellent dyeability.

[0003] Polyamides, formed by polycondensation of diamines and sebacic acid, are in high demand as environmentally friendly polyamide resins because sebacic acid is a plant-derived component, and they offer strength, durability, and heat resistance comparable to general-purpose nylons derived from petroleum, such as polyhexamethylene adipamide and polyhexamethylene capramide. However, a challenge remains in their significantly inferior dyeability compared to polyhexamethylene adipamide and polyhexamethylene capramide.

[0004] Against this backdrop, there is a demand for improving the staining properties of polyamides formed by polycondensation of diamines and sebacic acid.

[0005] Regarding the development of polyamides obtained by polycondensation of diamines and sebacic acid, for example, in the development of polypentamethylene sebakamid (N510) obtained by polycondensation of 1,5-pentanediamine and sebacic acid, Patent Document 1 describes that a polyamide with excellent color tone can be obtained by adding a heat-resistant agent having a sterically hindered N atom and a nitrogen-containing functional group that can react with at least one of the amino group, carboxyl group, and amide group constituting the polyamide. Patent Document 2 describes a method for obtaining a polyamide composition with excellent impact resistance and strength, comprising a polyamide containing 1,5-diaminopentane (1,5-pentanediamine) and a dicarboxylic acid component having 6 to 12 carbon atoms as main components, and a modified polyolefin resin. Patent Document 3 describes a method for obtaining a polyamide resin composition with excellent impact resistance, heat resistance, and water resistance, comprising a polyamide resin with tetramethylenediamine and sebacic acid as main components and an impact resistance improver as main components. Patent Document 4 describes a stocking with excellent gloss that has a defined amount of amino-terminal groups, and in its detailed description, it states that to improve dyeability, amino-terminal groups that act as dye-receptacle groups should be provided. As described in Patent Document 4, it is generally known that increasing the amount of amino-terminal groups improves the dyeability of polyamides. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] International Publication No. 2013 / 129371 [Patent Document 2] Japanese Patent Publication No. 2010-70701 [Patent Document 3] Japanese Patent Publication No. 2011-132519 [Patent Document 4] Japanese Patent Publication No. 2008-163470 [Overview of the project] [Problems that the invention aims to solve]

[0007] In the case of polyamides obtained by polycondensation of diamine and sebacic acid, because sebacic acid has a large number of carbon atoms, when trying to obtain a polyamide resin composition with a degree of polymerization suitable for clothing compared to general-purpose nylons such as polyhexamethylene adipamide and polyhexamethylene capramid, the amount of amino-terminated groups and carboxyl-terminated groups is significantly reduced, resulting in inferior dyeability.

[0008] While it is generally known that adding an excess of diamine components during polymerization is a way to increase the amount of amino-terminal groups, obtaining the desired amount of amino-terminal groups in polyamides formed by polycondensation of diamine and sebacic acid requires a large excess of diamine components. This disrupts the balance between diamine and dicarboxylic acid components, preventing the polymerization from reaching the desired degree. Alternatively, the polymerization time becomes long, leading to problems such as deterioration of chip color, thermal degradation of the polymer, an increase in microgels, and poor spinning performance.

[0009] The object of this invention is to obtain a polyamide resin composition with excellent dyeability and spinning operability, obtained by polycondensation of a diamine component and sebacic acid. [Means for solving the problem]

[0010] The present invention, which solves the above problems, has the following configuration. (1) A polyamide resin composition comprising a diamine component of 1,5-diaminopentane or 1,6-diaminohexane and sebaciic acid, wherein the amount of amino-terminated groups is 7.1 × 10 -5 ~10.0×10 -5 The value obtained by subtracting the carboxyl-terminal group from the amino-terminal group is 1.0 × 10⁻⁶ (mol / g). -5 ~6.5×10 -5 polyamide resin composition in mole / g Fibers made of . (2 ) The number of microgels with a major axis of 1 to 10 μm in the polyamide resin composition is 1000 or less per g. ru (1) of Fibers made from a polyamide resin composition. [Effects of the Invention]

[0011] The polyamide resin composition of the present invention can provide polyamide fibers with good spinning operability and excellent dyeability.

Embodiments for Carrying Out the Invention

[0012] The present invention relates to a polyamide resin composition obtained by polycondensing a diamine component and sebacic acid. The polyamide resin composition of the present invention is preferably a polyamide resin composition in which 90 mol% or more of the repeating units are composed of sebacic acid units. By containing a large amount of sebacic acid units, orientation crystallization becomes easier in the spinning process, so the regularity of the molecular chains of the resulting fibers increases, and the fibers have excellent mechanical properties, boiling water shrinkage rate, and further heat resistance. The ratio of sebacic acid units is more preferably 95 mol% or more, and even more preferably 98 mol% or more.

[0013] Within a range that does not impair the effects of the present invention, for example, a dicarboxylic acid component other than sebacic acid may be included in an amount of 10 mol% or less. Other dicarboxylic acids are not particularly limited, and examples include aliphatic dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, undecanedioic acid, dodecanedioic acid, brassylic acid, tetradecanedioic acid, pentadecanedioic acid, octadecanedioic acid, and aromatic dicarboxylic acids such as cyclohexanedicarboxylic acid, phthalic acid, isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid.

[0014] Sebacic acid can be derived from petroleum or biomass such as plants. In the present invention, sebacic acid obtained from biomass such as plant-derived raw materials is preferred. As a method for identifying whether sebacic acid is derived from biomass, for example, there is a method of measuring the content of radioactive carbon (C14). The details of the measurement method are standardized by ASTM (American Society for Testing and Materials), CEN (European Committee for Standardization), etc. In the United States, the ASTM-D6866 method is presented as a measurement standard for the biomass ratio. This measurement method is originally a standardized version of the radiocarbon dating method for determining the age of fossils and has been used for 60 years, so the technique has been established. Currently, the ASTM-D6866-04 method is also used for measuring the biomass content defined by JBPA (Japan BioPlastics Association) and JORA (Japan Organic Resources Association, Inc.).

[0015] The diamine component of the present invention can be arbitrarily selected. For example, ethylenediamine, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1,11-diaminoundecane, 1,12-diaminododecane, 1,13-diaminotridecane, 1,14-diaminotetradecane, 1,15-diaminopene Examples of diamines include aliphatic diamines such as tadecane, 1,16-diaminohexadecane, 1,17-diaminoheptadecane, 1,18-diaminooctadecane, 1,19-diaminononadecane, 1,20-diaminoeicosane, and 2-methyl-1,5-diaminopentane; alicyclic diamines such as cyclohexanediamine and bis-(4-aminohexyl)methane; and aromatic diamines such as xylylenediamine. One type of diamine component may be used, or two or more types of diamine components may be used. When multiple diamine components are mixed and used, it is preferable that the main diamine component accounts for 90 mol% or more of the repeating units of the total amount of the diamine components including the minor diamine components. By keeping it within this range, orientation crystallization is facilitated during the spinning process, which increases the regularity of the molecular chains of the resulting fibers, resulting in fibers with excellent mechanical properties, boiling water shrinkage rate, and heat resistance. The ratio of the main component diamine units is more preferably 95 mol% or more, and even more preferably 98 mol% or more.

[0016] When the polyamide resin composition of the present invention is used for clothing fibers, industrial fibers, or resin molding applications, from the viewpoint of processability and heat resistance, the melting point of the polymer is preferably 200 to 300°C, and it is preferable to select a diamine component that falls within this range. To obtain a polymer within this melting point range, the diamine component is preferably 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, or 1,10-diaminodecane. Furthermore, from the standpoint of industrial availability... 、 1,5-diaminopentane and 1,6-diaminohexane are more preferred.

[0017] In addition, the polyamide resin composition of the present invention can contain structural units derived from amino acids such as 6-aminocaproic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, and para-aminomethylbenzoic acid, and lactams such as ε-caprolactam and ω-laurolactam, within the range not impairing the effects of the present invention.

[0018] The polyamide resin composition of the present invention has an amino terminal group content of 7.1 ×10 -5 ~10.0×10 -5 mol / g, whereby a polyamide resin composition with excellent dyeability can be obtained. When dyeing for fiber applications, generally acid dyes are used, and by setting the amino terminal group content serving as the dyeing site within this range, an excellent dyeing effect can be obtained.

[0019] Since the dicarboxylic acid component of the polyamide resin composition of the present invention is sebacic acid, the methylene chain in the molecule is longer compared to polyhexamethylene adipamide (nylon 66) and polyhexamethylene capramide (nylon 6). Because the hydrophobic methylene chain is long, the hydrophobicity of the polymer increases, and the affinity with dyes tends to deteriorate. The present invention significantly increases the amino terminal group content compared to nylon 66 and nylon 6 to improve the dyeability. The amino terminal group content is 7.1 ×10 -5 mol / g or more ru . When the amino terminal group content exceeds 10.0×10 -5 mol / g, the dyeing fastness such as color fading during washing deteriorates.

[0020] For the polyamide resin composition of the present invention, the value obtained by subtracting the carboxyl terminal group content from the amino terminal group content is 1.0×10 -5 ~6.5×10 -5 mol / g. By setting the amino terminal group content and the carboxyl terminal group content within this range, a polyamide with good dyeability having a sufficiently large amino terminal group content is obtained, and thermal degradation is sufficiently suppressed. When the value obtained by subtracting the carboxyl terminal group content from the amino terminal group content is 1.0×10 -5When the concentration is less than mol / g, thermal decomposition of the polyamide resin composition progresses, and some of the molecular structures become three-dimensional (gelled). On the other hand, 6.5 × 10 -5 If the value is greater than mole / g, the difference between the amount of amino-terminal groups and carboxyl-terminal groups is too large, preventing sufficient polymerization. The value obtained by subtracting the amount of carboxyl-terminal groups from the amount of amino-terminal groups is 6.0 × 10⁻⁶. -5 Preferably 5.0 × 10 -5 A value of 1 / mol / g or less is more preferable.

[0021] The polyamide resin composition of the present invention is a polyamide with a sufficiently high amount of amino-terminal groups, and because the generation of substances that cause discoloration is sufficiently suppressed by inhibiting thermal degradation, a polyamide resin composition with good color tone can be obtained. Although the identification of discoloration-causing substances and their generation mechanisms are unknown, as even very small amounts of these substances can affect discoloration, it is presumed that this was achieved by optimizing the polymerization temperature, time, and pressure to inhibit thermal degradation. The degree of yellowing YI of the pellets is preferably 6.0 or less. The degree of yellowing YI refers to the value measured by the method described later. A low YI indicates less discoloration. Since high discoloration limits the range of applications and leads to a decrease in product value, a low YI is preferable. The degree of yellowing YI of the pellets of the polyamide resin composition of the present invention is more preferably 2.0 or less, and even more preferably 0.0 or less. The lower limit of the degree of yellowing YI is about -10.

[0022] The polyamide resin composition of the present invention preferably contains 1000 microgels / g or less, with a major axis of 1 to 10 μm. More preferably, the number of microgels is 700 / g or less, and even more preferably 600 / g or less. By lowering the polymerization temperature in the present invention, thermal degradation is sufficiently suppressed, and localized thermal degradation and gelation due to adhesion to the polymer can wall or other surfaces are also sufficiently reduced, resulting in a low content of micro-sized gels (microgels), which are thermal degradation products, in the polyamide resin composition. If there are many microgels in the polyamide resin composition, yarn breakage increases during melt spinning, leading to yarn production defects. The number of microgels referred to here is the value measured by the method described later.

[0023] The polyamide resin composition of the present invention preferably has a relative viscosity of 2.0 or higher at 25°C in a 98% sulfuric acid solution with a sample concentration of 0.01 g / mL. The relative viscosity is more preferably 2.05 to 7.0, even more preferably 2.1 to 6.5, and particularly preferably 2.15 to 6.0. A relative viscosity of 2.0 or higher is preferable as it allows for sufficient mechanical properties to be exhibited, while a relative viscosity of 8.0 or lower is preferable as it does not make molding difficult.

[0024] The polyamide resin composition of the present invention may be supplemented with known end-cap agents to adjust its molecular weight. Monocarboxylic acids are preferred as end-cap agents. Other examples include acid anhydrides such as phthalic anhydride, monoisocyanates, monoacid halides, monoesters, and monoalcohols.

[0025] There are no particular restrictions on the monocarboxylic acids that can be used as end-capturing agents, as long as they are reactive with an amino group. Examples include aliphatic monocarboxylic acids such as acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, lauric acid, tridecyl acid, myristic acid, palmitic acid, stearic acid, pivalic acid, and isobutyric acid; alicyclic monocarboxylic acids such as cyclohexanecarboxylic acid; and aromatic monocarboxylic acids such as benzoic acid, toluic acid, α-naphthalenecarboxylic acid, β-naphthalenecarboxylic acid, methylnaphthalenecarboxylic acid, and phenylacetic acid. In the present invention, one or more of these monocarboxylic acids can be used.

[0026] The polyamide resin composition of the present invention may contain other additives depending on the application, as long as they do not impair the effects of the present invention. These additives can be added during the polycondensation of the polyamide or by melt-mixing them with the polyamide resin composition. When melt-mixing, an extruder can be used.

[0027] Furthermore, these additives can also be incorporated by blending master chips containing these additives with chips, or by physically mixing them with pellets of polyamide resin composition and then subjecting them to molding processes such as spinning, extrusion, or injection molding.

[0028] Examples of such additives include antioxidants and heat stabilizers (hindered phenols, hydroquinones, phosphites and their derivatives, copper halides, iodine compounds, etc.), weathering agents (benzophenones, hindered amines, etc.), mold release agents and lubricants (aliphatic alcohols, aliphatic amides, etc.), pigments (titanium dioxide, carbon black, etc.), dyes (nigrosine, aniline black, etc.), nucleating agents (talc, silica, kaolin, clay, etc.), antistatic agents (polyetheramide antistatic agents, polyether esteramide antistatic agents, etc.), flame retardants (melamine cyanurate, magnesium hydroxide, etc.), fillers (graphite, barium sulfate, magnesium sulfate, calcium carbonate, magnesium carbonate, etc.), and other polymers (other polyamides, polyethylene, polypropylene, polyester, polycarbonate, etc.).

[0029] The polycondensation method of polyamide is not particularly limited in the present invention, but preferred manufacturing methods for obtaining the polyamide resin composition of the present invention are shown.

[0030] Polyamide polycondensation methods generally include continuous polymerization and batch polymerization, and production is possible using either method. The batch polymerization method for polyamide polycondensation is outlined below, using polypentamethylene sebacamid as an example.

[0031] An aqueous solution of equimolar salts of sebacic acid and 1,5-diaminopentane is prepared and concentrated by heating in a pressure vessel (concentration step). The water content of the equimolar salt aqueous solution can be adjusted considering the convenience of handling and weighing, but 10-60% is preferred, and 10-50% is more preferred. Concentration can also be performed in a separate apparatus from the polycondensation apparatus to an arbitrary water content, in which case the water content after concentration is preferably 10-30%, and 10-20% is more preferred.

[0032] To the concentrated equimolar aqueous solution of the salt, 1,5-diaminopentane is added in an amount that meets the desired amino-terminal group requirements. While the addition of 1,5-diaminopentane can be done before concentration, it is preferable to add it after concentration to minimize evaporation during concentration.

[0033] The concentrated equimolar aqueous solution of the salt is heated in a sealed container until it reaches the target pressure (pressurization step). The maximum pressure inside the container is preferably 1.0 MPa or higher, more preferably 1.3 MPa (absolute pressure) or higher, and even more preferably 1.7 MPa or higher. If the maximum pressure is 1.0 MPa or higher, the evaporation of 1,5-diaminopentane can be reduced. There is no particular upper limit to the maximum pressure, but considering the pressure resistance of the polycondensation apparatus, it is preferably 3.0 MPa or lower, and even more preferably 2.0 MPa or lower.

[0034] While maintaining the above pressure, the container is allowed to evaporate moisture until the internal temperature reaches 240-250°C (pressure reduction step). Then, while continuing heating, the internal pressure of the container is gradually reduced to 0.1 MPa (atmospheric pressure) (pressure release step). The temperature at which pressure release begins is important; if it is 240°C or higher, polycondensation can occur without the internal liquid solidifying during the pressure release step, and if it is 250°C or lower, thermal degradation of the polymer can be suppressed.

[0035] To proceed with polycondensation after the depressurization process, there are two methods: removing condensation water by circulating an inert gas while the internal pressure of the container is at atmospheric pressure (atmospheric pressure polymerization), and reducing the internal pressure of the container (reduced pressure polymerization). When the internal pressure of the container is reduced, the water in the polymer vaporizes rapidly and foams, causing the polymer to adhere to the can wall, where it is heated and thermally degraded. This thermally degraded material is then mixed back into the polymer liquid, generating microgels. Therefore, atmospheric pressure polymerization is preferred in this invention. Examples of inert gases include helium gas, argon gas, and nitrogen gas, with nitrogen gas being preferred from a cost perspective.

[0036] This invention involves adding 1,5-diaminopentane to obtain a polyamide resin composition with a high amino-terminal group content. However, the molar balance between the diamine component and sebacic acid during polymerization is disrupted, slowing down the polymerization rate and requiring a long time for polycondensation. By increasing the amount of inert gas flowed to 0.3 L / min or more per kg of polymer, the polycondensation time can be shortened by efficiently discharging the condensation water and unreacted 1,5-diaminopentane from the gas phase to the outside of the polymerization vessel. Furthermore, thermal degradation of the polymer can also be suppressed. The flow rate of the inert gas is preferably 0.5 to 1.0 L / min.

[0037] The reaction time for polymerization at atmospheric pressure to advance polycondensation to the desired degree of polymerization is preferably 20 to 50 minutes, and more preferably 20 to 40 minutes.

[0038] Furthermore, it is preferable that the maximum temperature inside the container for atmospheric pressure polymerization be 240 to 250°C. By setting the maximum temperature within this range, thermal degradation can be suppressed even when atmospheric pressure polymerization is carried out for a long time, and deterioration of the polymer's color and the generation of microgels can be reduced. The maximum temperature is more preferably 245 to 250°C. If the maximum temperature is 240°C or higher, the melt viscosity of the polymer can not be increased too much, and good fluidity can be maintained inside the container. Also, if the maximum temperature is 250°C or lower, deterioration of the polymer's color and the generation of microgels due to thermal degradation can be suppressed.

[0039] The preferred polymerization conditions for polyhexamethylene sebakamid, which consists of 1,6-diaminohexane and sebamic acid, are the same as the preferred polycondensation method for polypentamethylene sebakamid described above.

[0040] In the case of polytetramethylene sebakamid, which consists of 1,4-diaminobutane and sebamic acid, the melting point of the polyamide resin composition is high, so the maximum temperature in the container for atmospheric pressure polymerization is preferably 250 to 260°C, and more preferably 255 to 260°C. If the maximum temperature is 250°C or higher, the fluidity in the container can be maintained well without the melt viscosity of the polymer becoming too high. Furthermore, if the maximum temperature is 260°C or lower, deterioration of the polymer's color can be suppressed.

[0041] The resulting polyamide resin composition is preferably extruded from the container in strand form and cut into pellets. The molecular weight can also be increased by solid-phase polymerization of these pellets. In solid-phase polymerization, the molecular weight can be further increased by heating in a vacuum or inert gas at a temperature range of 100°C to the melting point. [Examples]

[0042] The present invention will be further described with reference to the following examples, but the present invention is not limited to the descriptions in these examples.

[0043] [Relative viscosity (ηr)] 0.25 g of the sample was dissolved in 100 ml of 98 wt% sulfuric acid to a total volume of 1 g, and the flow time (T1) at 25°C was measured using an Ostwald viscometer. Subsequently, the flow time (T2) of 98 wt% sulfuric acid alone was measured. The ratio of T1 to T2, i.e., T1 / T2, was defined as the relative viscosity of the sulfuric acid.

[0044] [Amino-terminal group] One g of the sample was dissolved in 50 mL of a phenol / ethanol mixed solution (phenol / ethanol = 80 / 20) by shaking at 30°C to prepare a solution. This solution was then titrated with 0.02 N hydrochloric acid to determine the amount of 0.02 N hydrochloric acid required. Additionally, the same amount of the phenol / ethanol mixed solvent was titrated with 0.02 N hydrochloric acid to determine the amount of 0.02 N hydrochloric acid required. The difference between these two titrations was used to determine the amount of amino groups per kilogram of sample.

[0045] [Carboxylate-terminal group weight] 0.5 g of the sample was accurately weighed, dissolved in 20 ml of benzyl alcohol at 195°C, and then titrated at 195°C with phenolphthalein as an indicator using a 0.02 N potassium hydroxide ethanol solution to determine the amount of carboxyl-terminal groups (mol / ton).

[0046] [Yellowing degree YI] The YI value of the pellets was measured using a color computer manufactured by Suga Test Instruments Co., Ltd. The measurement method followed JIS K7373 (2006) (Test method for the optical properties of plastics: yellowness).

[0047] [Number of microgels] 240g of pellets were melted at a melting point of +40°C, and a filtration area of ​​3.1cm² with a mesh opening of 5μm was obtained. 2 Filter for 1 hour using a filter to capture the microgel (1.3 g / cm³). 2 (minutes). 20 ml of phenol-ethanol mixture (phenol 83.5%, manufactured by Katayama Chemical Industry Co., Ltd.) was added to the removed filter, and the polymer solidified in the filter was dissolved over 24 hours at room temperature, and the microgel was extracted. The solvent containing this microgel was filtered under reduced pressure through a membrane filter (mesh size 0.45 μm). Here, the filtration area of ​​the membrane filter was 960 mm². 2 The microgel contained in 1 g of the polycapramid resin composition has a filtration area of ​​4 mm². 2 This is a calculation that exists in (960mm 2 (240g). The filtered sample was observed under a fluorescence microscope (200x magnification), and a representative field of view was captured as a digital image (field of view 0.04mm). 2 The images were imported into the image. An image analyzer (Win ROOF, manufactured by Mitani Corporation) was used to automatically count the number of bright spots in the digital image and the major axis of each bright spot. The total number of bright spots with a major axis of 1 μm to 10 μm observed in 5 fields was further multiplied by 20, and the filtration area was 4 mm². 2 This was defined as the number of microgels per 1g of polycapramid-based yarn material.

[0048] [Number of times the thread broke] The number of yarn breaks per 100 kg of production was calculated and expressed as breaks / 100 kg. The criteria for judging the quality of operation based on the number of breaks were as follows: 0-1 breaks / 100 kg or less: good productivity; 2-5 breaks / 100 kg: poor operation, but production is possible by optimizing the spinning conditions; 6 breaks / 100 kg or more: poor operation and unsuitable for production.

[0049] [Stainability] A. Making tubular knitted fabric The fabric was manufactured using a tubular knitting machine, adjusted to achieve a thread count of 50. If the fineness of the fibers was low, the fibers were appropriately blended so that the total fineness of the fibers fed into the tubular knitting machine was between 50 and 100 dtex. If the total fineness exceeded 100 dtex, only one strand of yarn was fed into the tubular knitting machine, and the fabric was manufactured using the same method as described above, adjusted to achieve a thread count of 50.

[0050] B. Scouring of tubular knitted fabric The tubular knitted fabric obtained in A above was washed with a 2g / l aqueous solution of nonionic surfactant (Neugen, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) at 60°C for 30 minutes, then rinsed with running water for 20 minutes, dehydrated in a spin dryer, and air-dried.

[0051] C. Dyeing of tubular knit fabric The tubular knitted fabrics obtained in A and B above were dyed using the following dyes and dyeing auxiliaries. Acid dye: Erionyl Blue AR 2.0% by mass Staining aid: Acetic acid 1.5% The fabric was dyed in a dyeing bath containing acid dyes and dyeing aids at atmospheric pressure and a temperature of 98°C for 45 minutes, then rinsed with running water for 20 minutes, dehydrated in a spin dryer, and air-dried.

[0052] D. Color development The color development of the tubular knitted fabric after dyeing, obtained in C above, was evaluated in the following three stages. S: The entire area is uniformly colored from medium (light to dark) to dark. A: The entire surface is uniformly colored in light to medium (light to dark) shades. B: The entire surface is uniformly colored with a light color.

[0053] Reference Example 1 (Preparation of lysine decarboxylase) The E. coli JM109 strain was cultured as follows. First, the strain was inoculated into 5 ml of LB medium using one loop of platinum and pre-cultured by shaking at 30°C for 24 hours. Next, 50 ml of LB medium was placed in a 500 ml Erlenmeyer flask and pre-sterilized by steam at 115°C for 10 minutes. The pre-cultured strain was subcultured into this medium and cultured for 24 hours at an amplitude of 30 cm and 180 rpm, while adjusting the pH to 6.0 with 1N hydrochloric acid solution. The resulting cells were collected, and cell-free extracts were prepared by sonication and centrifugation. The lysine decarboxylase activity of these extracts was measured according to standard procedures (Kenji Soda, Haruo Misono, Biochemistry Experiment Course, vol. 11, pp. 179-191 (1976)).

[0054] When lysine is used as a substrate, conversion by lysine monooxygenase, lysine oxidase, and lysine mutase, which are considered to be the primary pathways, may occur. Therefore, to block this reaction system, the cell-free extract of E. coli strain JM109 was heated at 75°C for 5 minutes. Furthermore, this cell-free extract was fractionated with 40% saturated and 55% saturated ammonium sulfate. Using the crude purified lysine decarboxylase solution obtained in this way, 1,5-pentanediamine was produced from lysine.

[0055] Reference Example 2 (Production of 1,5-diaminopentane) 1000 ml of an aqueous solution prepared to contain 50 mM lysine hydrochloride (manufactured by Wako Pure Chemical Industries, Ltd.), 0.1 mM pyridoxal phosphate (manufactured by Wako Pure Chemical Industries, Ltd.), and 40 mg / L crude purified lysine decarboxylase (prepared in Reference Example 1) was reacted at 45°C for 48 hours while maintaining the pH at 5.5-6.5 with 0.1 N hydrochloric acid aqueous solution to obtain 1,5-diaminopentane hydrochloride. Sodium hydroxide was added to this aqueous solution to convert 1,5-diaminopentane hydrochloride to 1,5-diaminopentane, which was extracted with chloroform and then distilled under reduced pressure (1066.58 Pa, 70°C) to obtain 1,5-diaminopentane.

[0056] Reference Example 3 (Preparation of a 40% by weight aqueous solution of 1,5-diaminopentane sebacate) In Reference Example 2, an aqueous solution of 1,5-diaminopentane, prepared by diluting it with deionized water, was immersed in an ice bath and stirred. Small amounts of sebacic acid (manufactured by Kirk Co., Ltd.) in equimolar amounts to 1,5-diaminopentane were added little by little. Near the neutralization point, the solution was heated in a 40°C water bath to bring the internal temperature down to 33°C, thereby preparing a 40% by weight aqueous solution of 1,5-diaminopentane / sebacic acid equimolar salt. A 40% by weight aqueous solution of 1,6-diaminohexane / sebacic acid equimolar salt and a 40% by weight aqueous solution of 1,4-diaminobutane / sebacic acid equimolar salt were prepared using the same method.

[0057] Example 1 300 kg of a 40 wt% aqueous solution of 1,5-diaminopentane sebaciate obtained in Reference Example 3 was placed in a jacketed autoclave. After thoroughly purging the container with nitrogen, it was heated and concentrated until the water content of the aqueous solution reached 15 wt% while maintaining a container temperature of 200°C and a container pressure of 0.2 MPa (gauge pressure) (concentration step). The concentration of the aqueous solution in the container was determined from the amount of distillate. After concentration, 0.013 moles of 1,5-diaminopentane obtained in Reference Example 2 were added to the molal salt of 1,5-diaminopentane sebaciate to achieve the target amount of amino terminal groups. The solution was then transferred to an autoclave equipped with a stirrer and a heat transfer medium jacket, heated to a heat transfer medium temperature of 290°C, and the pressure was increased to a container pressure (gauge pressure) of 1.7 MPa while stirring at 30 rpm (pressurization step). Next, the internal pressure (gauge pressure) of the container was controlled to 1.7 MPa and maintained until the internal temperature reached 245°C (pressure control step). Then, the pressure was released to atmospheric pressure over 50 minutes (pressure release step). While adjusting the heating temperature so that the internal temperature at the end of atmospheric pressure polymerization was between 245°C and 250°C, nitrogen gas was circulated at a rate of 0.5 L / min (50 L / min) per kg of polymer and blown for 30 minutes to increase the degree of polymerization (atmospheric pressure step). Then, a nitrogen pressure of 0.5 MPa (absolute pressure) was applied to the container, and the polyamide resin composition obtained by polycondensation was extruded into strands with a diameter of approximately 3 mm, cut to a length of approximately 4 mm, and 100 kg of pellets were obtained (discharge step). The results for the obtained polyamide resin composition are shown in Table 1.

[0058] The obtained polyamide resin composition was dried to a moisture content of 0.03% by weight or less, and then melt-extruded at a spinning temperature of 280°C through a spinneret with 24 extrusion holes (hole diameter 0.2 mm, hole elongation 0.7 mm) at an extrusion rate of 28 g / min. After melt-extrusion, the material was cooled, lubricated, and entangled, then taken up with a Godet roller at 1900 m / min, subsequently stretched to 1.9 times its original length, and then heat-set at 155°C. A fiber with a total fineness of 22 decitex and 24 filaments was obtained at a winding speed of 3500 m / min. There were no yarn breaks when spinning 100 kg of polyamide resin composition.

[0059] (Example 2) Polyamide resin composition pellets were obtained under the polymerization conditions shown in Table 1, except that after concentration, 0.0014 moles of benzoic acid and 0.01 moles of 1,5-diaminopentane sebaciate were added to the 1,5-diaminopentane sebaciate. Other conditions were the same as in Example 1.

[0060] ( reference Example 3) Polyamide resin composition pellets were obtained under the polymerization conditions shown in Table 1, except that after concentration, 0.0042 moles of benzoic acid and 0.012 moles of 1,5-diaminopentane sebaciate were added to the 1,5-diaminopentane sebaciate. Other conditions were the same as in Example 1.

[0061] ( reference Example 4) Polyamide resin composition pellets were obtained under the polymerization conditions shown in Table 1, except that after concentration, 0.0110 moles of benzoic acid and 0.012 moles of 1,5-diaminopentane sebaciate were added to the 1,5-diaminopentane sebaciate. Other conditions were the same as in Example 1.

[0062] (Example 5) Polyamide resin composition pellets were obtained under the polymerization conditions shown in Table 1, except that 0.016 moles of 1,5-diaminopentane were added to the 1,5-diaminopentane sebaciate after concentration. Other conditions were the same as in Example 1.

[0063] (Example 6) Polyamide resin composition pellets were obtained under the polymerization conditions shown in Table 1, except that a 40% by weight aqueous solution of 1,6-diaminohexane-sebacic acid was used, and after concentration, 0.013 moles of 1,6-diaminohexane were added to the molal salt of 1,6-diaminohexane-sebacic acid. Other conditions were the same as in Example 1.

[0064] ( reference Example 7) Polyamide resin composition pellets were obtained under the polymerization conditions shown in Table 1, except that after concentration, 0.0042 moles of benzoic acid and 0.012 moles of 1,6-diaminohexane were added to the 1,6-diaminohexane sebacic acid etomolar salt. Other conditions were the same as in Example 6.

[0065] ( reference Example 8) Polyamide resin composition pellets were obtained under the polymerization conditions shown in Table 1, except that a 40% by weight aqueous solution of 1,4-diaminobutane-sebacic acid was used, and after concentration, 0.013 moles of 1,4-diamibutane were added to the 1,4-diaminobutane-sebacic acid equimolar salt. Other conditions were the same as in Example 1.

[0066] (Example 9) Polyamide resin composition pellets were obtained under the polymerization conditions shown in Table 1, except that 5.0% by weight of ε-caprolactam was added to 1,5-diaminopentane sebaciate after concentration. Other conditions were the same as in Example 1.

[0067] (Example 10) Polyamide resin composition pellets were obtained under the polymerization conditions shown in Table 1, except that after the depressurization process, the pressure inside the container (gauge pressure) was reduced to -13 kPa and maintained for 25 minutes (reduced pressure polymerization). Other conditions were the same as in Example 1.

[0068] [Table 1]

[0069] (Comparative Example 1) Polyamide resin composition pellets were obtained under the polymerization conditions shown in Table 2, except that 1,5-diaminopentane was omitted after concentration. Other conditions were the same as in Example 1.

[0070] (Comparative Example 2) Polyamide resin composition pellets were obtained under the polymerization conditions shown in Table 2, except that 1,5-diaminopentane was omitted after concentration. Other conditions were the same as in Example 2.

[0071] (Comparative Example 3) Polyamide resin composition pellets were obtained under the polymerization conditions shown in Table 2, except that 0.002 moles of 1,5-diaminopentane were added to the 1,5-diaminopentane sebaciate after concentration. Other conditions were the same as in Example 1.

[0072] (Comparative Example 4) Polyamide resin composition pellets were obtained under the polymerization conditions shown in Table 2, except that the heating temperature was adjusted so that the maximum temperature inside the container at the end of the atmospheric pressure phase was 281°C. Other conditions were the same as in Example 1.

[0073] (Comparative Example 5) Except for adjusting the heating temperature in Example 6 so that the maximum temperature inside the container at the end of atmospheric pressure was 281°C, polyamide resin composition pellets were obtained under the polymerization conditions shown in Table 2.

[0074] (Comparative Example 6) reference Except for adjusting the heating temperature in Example 8 so that the maximum temperature inside the container at the end of atmospheric pressure was 285°C, polyamide resin composition pellets were obtained under the polymerization conditions shown in Table 2.

[0075] (Comparative Example 7) In Example 10, the heating temperature was adjusted so that the maximum temperature inside the container at the end of reduced pressure was 281°C. Otherwise, polyamide resin composition pellets were obtained under the polymerization conditions shown in Table 2.

[0076] Table 2

Claims

1. A fiber made from a polyamide resin composition comprising a diamine component of 1,5-diaminopentane or 1,6-diaminohexane and sebaic acid, wherein the amount of amino-terminal groups is 7.1 × 10⁻⁵ to 10.0 × 10⁻⁵ mol / g, and the value obtained by subtracting the amount of carboxyl-terminal groups from the amount of amino-terminal groups is 1.0 × 10⁻⁵ to 6.5 × 10⁻⁵ mol / g.

2. A fiber made from the polyamide resin composition according to Claim 1, wherein the number of microgels with a major axis of 1 to 10 μm in the polyamide resin composition is 1000 or less per g.

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