JP2019019319A - Polyamide resin composition and method for producing the same - Google Patents

Abstract

To provide a carbon black-containing polyamide resin composition that has excellent dispersibility, suppresses rise in filtration pressure during melting spinning and has excellent spinning properties.SOLUTION: The present invention provides a polyamide resin composition that can be used to obtain a black spun-dyed master pellet with a carbon black concentration of 12.5 wt.%-20.0 wt.%, wherein, when it is blended with a base pellet for a carbon black concentration to be 2.5 wt.%, it has a filtration pressure rise ΔP[MPa/10hr] of 1.0 or less with a 5 μm filter.SELECTED DRAWING: None

Description

  The present invention relates to a polyamide resin composition. More specifically, the present invention relates to a homogeneous black original polyamide resin composition having good carbon black dispersibility with respect to polyamide.

  In general, polyamide resins have been used for clothing fibers and industrial fibers taking advantage of their excellent properties. Further, it is widely used as an injection-molded product in the automobile field, the electric / electronic field, etc., and as an extruded film in food packaging applications. When coloring these polyamide resin fibers, films, molded articles, etc., original polyamide master pellets by adding pigments such as carbon black are used. However, the polyamide resin containing a large amount of these pigments has a good pigment dispersibility because the dispersion of the pigment in the polyamide resin becomes insufficient and the color developability tends to vary as compared with the case of dyeing with a dye. There is a need for polyamide resins.

  As a method for producing the original polyamide master pellets, there are known production methods such as a method in which a pigment is added and polymerized by heating at the polyamide monomer stage, or a method in which the polyamide composition is remelted and the pigment is kneaded and added.

  In the method of heating and polymerizing by adding a pigment at the polyamide monomer stage, when a high-concentration pigment is used, the amount of pigment added to the polyamide is relatively increased, and carbon black is aggregated and the dispersibility tends to deteriorate. This method is mainly used for low-concentration original polyamides with a carbon black concentration of up to about 5 wt%. To solve this problem, for example, in Patent Document 1, a surfactant is added to improve dispersibility. Original polyamide has been proposed.

  Patent Document 2 proposes a black polyamide having improved dispersibility by adding a high-concentration carbon black to a monomer material after adding a dispersant.

  On the other hand, Patent Document 3 and Patent Document 4 do not disclose a specific method for producing a master pellet, but after remelting a polyamide resin composition and adding high-concentration carbon black to obtain a master pellet. A black original polyamide fiber obtained by blending with a base pellet has been proposed. Such a technique of blending master pellets and base pellets for melt spinning is generally used because equipment costs are low and productivity is improved.

Japanese Patent Publication No. 38-20974 Japanese Patent Publication No. 47-24280 JP 2010-196226 A JP-A-2015-71839

  However, in the case of the original polyamide described in Patent Document 1, only a low concentration original polyamide having a carbon black concentration of about 3 wt% can be stably obtained. When the carbon black concentration is set to a high concentration of 12.5 wt% or more, There is a problem that the carbon black aggregates and dispersibility deteriorates. Further, although the use of a surfactant and a viscosity stabilizer has been improved, the dispersibility has not been sufficiently improved due to the aggregation of carbon black in the polyamide.

  The original polyamide described in Patent Document 2 is polymerized using a low concentration monomer having a lactam concentration of about 20 wt% diluted with water as a raw material. Aggregation tends to occur and there is a problem of deterioration in dispersibility. Furthermore, since it is necessary to evaporate a large amount of contained water, the amount of energy consumption is large and there is a problem in productivity.

  In the original polyamide fiber described in Patent Document 3, carbon black is added when the terpolymer polyamide is re-melted. Black secondary aggregation tends to occur. Therefore, the dispersibility at the time of spinning deteriorates, the filtration pressure at the time of melt spinning tends to increase, and there is a problem that the manufacturability of the yarn is deteriorated.

  On the other hand, the black original polyamide fiber described in Patent Document 4 is a master chip in which carbon black is added to a base polymer nylon 6 chip as in Patent Document 3, but is remelted in the same manner as Patent Document 3. Since carbon black is sometimes added, the dispersion of carbon black tends to become uneven, and there is a similar problem. In order to remove coarse particles of carbon black in polyamide, there is a description of a method of removing agglomerated carbon black by combining a plurality of filters of 10 μm to 30 μm, but the aggregate of carbon black present in the master pellet It was not enough to solve the problem.

  Against this background, as a result of intensive studies, the present inventors have found that, in order to solve the conventional problems, the polyamide has a good pigment dispersibility, suppresses an increase in the filtration pressure during melt spinning, and has a good spinning property. A polyamide resin composition was found.

In order to solve the above problems, the present invention has the following configuration.
(1) Filtration pressure with a 5 μm filter when the carbon black concentration is 12.5 wt% to 20.0 wt% black original master pellets and blended with the base pellet to make the carbon black concentration 2.5 wt% A polyamide resin composition having a degree of increase ΔP [MPa / 10 hr] of 1.0 or less.
(2) When producing a polyamide resin composition having a carbon black concentration of 12.5 wt% to 20.0 wt% by polycondensation reaction of the polyamide monomer raw material solution, an average of the polyamide monomer raw material solution having a moisture concentration of 15 wt% to 60 wt% Polyamide monomer raw material having a water concentration of 10 wt% to 30 wt% added to a polyamide resin composition capable of obtaining carbon black having a particle size of 0.1 µm to 0.2 µm, and then concentrated to a concentration of 10 wt% to 30 wt% A method for producing a polyamide resin composition, comprising subjecting the polyamide monomer raw material solution to a polycondensation reaction as a solution.

  Since the polyamide resin composition of the present invention has good dispersibility of the pigment, it is possible to produce a polyamide fiber with good spinning performance with little increase in filtration pressure during melt spinning.

  The present invention is described in detail below.

  The polyamide constituting the polyamide resin composition of the present invention is a resin composed of a high molecular weight body in which so-called hydrocarbon groups are connected to the main chain via an amide bond. Such polyamides are excellent in yarn-making properties and mechanical properties, and polycaproamide (nylon 6) and polyhexamethylene adipamide (nylon 66) are mainly preferred. Polycaproamide (nylon 6) is more preferable. For example, “mainly” as used herein for polycaproamide (nylon 6) means that it is 80 mol% or more of all monomer units as ε-caprolactam units constituting polycaproamide, more preferably 90 mol%. That's it. Examples of other components include, but are not limited to, polydodecanoamide, polyhexamethylene adipamide, polyhexamethylene azelamide, polyhexamethylene sebamide, polyhexamethylene dodecanoamide, polymetaxylylene adipa Examples thereof include units such as aminocarboxylic acid, dicarboxylic acid, and diamine, which are monomers constituting imide, polyhexamethylene terephthalamide, polyhexamethylene isophthalamide and the like.

  The degree of polymerization of the polyamide is preferably in the range of 1.0 to 3.0 with 98% sulfuric acid relative viscosity at 25 ° C., more preferably 1.5 for stable pelletization after polymerization. It is in the range of ˜2.7.

  Examples of the carbon black used in the polyamide resin composition of the present invention include furnace black, channel black, thermal black, acetylene black, lamp black and the like, and are not particularly limited. Furnace black or channel black is preferred from the standpoint of handling and stability.

  The carbon black production method is divided into acetylene black and thermal black as the pyrolysis method, and oil smoke collection (so-called lamp black) and furnace black as the incomplete combustion method. give. The thermal decomposition method that must maintain a reaction environment near 2000 ° C. requires a lot of energy for production, and thus has low practicality in terms of cost and production environment. On the other hand, the incomplete combustion method is highly practical in terms of cost and manufacturing environment. In addition, the furnace method, which is a typical incomplete combustion method, can easily control the particle size and structure size, and can be obtained by the furnace method from the color tone of the polyamide black original pellets and the spinning properties during melt spinning. It is preferable to use furnace black. For the production of furnace black, furnace black obtained by an oil furnace method is more preferred.

  In addition, a structure is formed in the production stage of carbon black. The structure is the smallest unit of carbon black, and its index can be indicated by the DBP oil absorption. The DBP oil absorption referred to here is a value measured according to JIS K6217-4 (2008). The DBP oil absorption of the carbon black used in the present invention is preferably 10 to 300 ml / 100 g. By setting the DBP oil absorption amount to 10 ml / 100 g or more, light in a high wavelength region is not scattered, and when a polyamide black original pellet is formed, a deep black color can be produced. The carbon black contained in the polyamide resin composition of the present invention preferably has an average particle size of 0.1 to 0.2 μm as the particle size of the polyamide monomer raw material solution stage. Further, the average particle size of 0.2 μm or less is preferably 70% or more of the whole, and more preferably 80% or more. By aligning the particle diameter, secondary aggregation of carbon black in the polymerization process is suppressed, and when the polyamide resin composition is polymerized, variation in particle diameter can be suppressed.

  The polyamide resin composition of the present invention is a black original polyamide pellet having a carbon black concentration of 12.5 wt% to 20.0 wt%. By setting it within this range, it is possible to obtain a homogeneous original polyamide resin composition having good carbon black dispersibility with respect to polyamide, and a polyamide fiber having good spinning properties by suppressing an increase in filtration pressure during melt spinning. can get. If it exceeds 20.0 wt%, the dispersibility of carbon black in the raw material monomer will decrease, and a homogeneous black original polyamide resin composition will not be obtained, and the filtration pressure will increase easily during melt spinning, resulting in increased yarn breakage and yarn-manufacturability. Gets worse. When the amount is less than 12.5 wt%, the relative viscosity of the polyamide increases in the polymerization stage, and thus a viscosity modifier is generally required to maintain a stable degree of polymerization. Causes aggregation and dispersion. The concentration range of carbon black is preferably 12.5 wt% to 18.0 wt%.

  You may add dispersing agents, such as surfactant, in arbitrary ratios in the polyamide resin composition of this invention. Examples of the dispersant include nonionic surfactants and anionic surfactants.

  The polyamide resin composition of the present invention has a filtration pressure increase ΔP [MPa / 10 hr] of 1.0 or less with a 5 μm filter when blended with a base pellet to a carbon black concentration of 2.5 wt%. Preferably it is 0.6 or less, More preferably, it is 0.4 or less. Here, ΔP is an index that simply indicates an increase in the filtration pressure during melt spinning, and by making it within this range, a homogeneous original polyamide resin composition having good carbon black dispersibility with respect to polyamide. Thus, a black original polyamide fiber having good yarn-making properties can be obtained by suppressing an increase in filtration pressure during fiber production. When ΔP exceeds 1.0, the dispersibility of carbon black with respect to polyamide is reduced, and not only a homogeneous black original polyamide resin composition can be obtained, but also an increase in filtration pressure is induced during melt spinning which is the next step. Operability deteriorates due to frequent cutting.

  The method for producing the polyamide resin composition of the present invention will be described below. The moisture concentration here is the moisture concentration in the polyamide raw material solution. In order to control ΔP of the polyamide resin composition of the present invention within such a range, moisture in the polyamide monomer raw material solution is gently removed, and the moisture concentration in the monomer before polymerization is controlled to 10 wt% to 30 wt%. Can be controlled. Specifically, it is as follows.

  The carbon black used in the present invention may be added to the raw material monomer in advance as a slurry mixed with water, or may be directly added and mixed with the raw material monomer as a powder.

  The carbon black contained in the polyamide resin composition of the present invention preferably has an average particle size of 0.1 to 0.2 μm as the particle size of the polyamide monomer raw material solution stage. Further, the average particle size of 0.2 μm or less is preferably 70% or more of the whole, and more preferably 80% or more.

  The water concentration of the carbon black slurry is preferably 15 wt% to 60 wt%, more preferably 20 wt% to 50 wt%. If the water concentration of the slurry dispersion is 15 wt% or more, the viscosity in the monomer raw material solution is not too high and the dispersibility of the carbon is good. Easy to manage production. If the water concentration of the slurry dispersion is 60 wt% or less, it will not be excessive, the amount of water evaporation during heating will be small, the dispersibility of carbon black will be good, and a great amount of energy will not be required for water evaporation. The color tone of the composition is also good.

  It is necessary to gently remove excess water in the polyamide monomer raw material solution. The temperature of the polyamide monomer raw material solution at that time is 80 ° C. to 170 ° C., and the internal pressure of the can is −0.07 MPa to 0.30 MPa (gauge pressure). A range is preferable. When excess water is removed, stirring may be performed or stirring may not be performed. Judgment of completion of concentration is calculated from the amount of distilled water distilled out of the system. By controlling the moisture content of the raw material solution at the stage of the polyamide monomer raw material solution before the start of polycondensation within this range, it is possible to minimize the weight change due to the decrease in the water content at the polycondensation stage. Thereby, the aggregation of carbon black can be suppressed, the filtration pressure increase ΔP can be reduced to 1.0 or less, and a polyamide resin composition having good dispersibility can be obtained. When the polycondensation reaction is performed at a moisture content of the polyamide monomer raw material solution of 30 wt% or less, rapid evaporation of moisture due to high-temperature heating does not occur, carbon black does not easily aggregate, and dispersibility is improved. More preferably, it is 20 wt% or less.

  The lower limit of the moisture content of the polyamide monomer raw material solution before the start of polycondensation is 10 wt%. When batch polymerization is performed at a moisture content of 10 wt% or more, the reaction pressure rises to a specified reaction pressure.

  The degree of concentration can be calculated from the amount of distilled water distilled out of the system. The degree of concentration (Δconcentration) is the difference between the water content (wt%) in the polyamide monomer raw material solution before concentration and the water content (wt%) in the polyamide monomer raw material solution after concentration, that is, before the start of polycondensation Can be sought. Here, by setting the Δ concentration to 5 wt% to 50 wt%, the filtration pressure increase ΔP of the present invention can be made suitable. More preferably, it is 10 wt%-40 wt%.

  There is no particular limitation on the polymerization reaction apparatus for producing the polyamide resin composition of the present invention, and any apparatus can be used as long as it is a commonly used apparatus. The step of removing moisture and the step of proceeding the polycondensation reaction at high temperature are essential. In this case, the reaction apparatus may be one tank or may be a divided two-tank apparatus.

  The polyamide resin composition of the present invention is discharged from the polymerization reactor in the form of a strand, etc., once cooled / cut into pellets, and then extracted and removed residual monomers and oligomers with hot water, etc. Drying removes moisture and gives pellets suitable for fibers.

  In the method for producing a polyamide resin composition of the present invention, after the polyamide resin composition is polymerized in the liquid phase, solid-phase polymerization is performed as necessary to further increase the degree of polymerization within a range that does not impair the object of the present invention. It can be carried out.

  As the solid phase polymerization, there is a solid phase polymerization method that is performed at a melting temperature or lower. Since the operation is performed at a temperature lower than the melting temperature, it is safer than liquid phase polymerization and can suppress thermal degradation of the polymer itself. The carbon black dispersibility inside does not deteriorate.

  Heat treatment equipment for performing solid-phase polymerization includes a rotary batch vacuum dryer that heats a jacket by circulating a heating medium, and a tower-type continuous discharge dryer that circulates heated nitrogen. As long as it is possible to discharge condensed water, it may contain anything that is effective for the preliminary drying equipment, stirrer, etc. in the previous stage.

  It is possible to obtain a polymer whose viscosity has been increased to a desired viscosity by putting the polymer obtained by liquid phase polymerization into a solid phase polymerization facility and continuing heating at a temperature of 150 to 175 ° C. In the meantime, for example, if it is a vacuum dryer, the vacuum of 200 Pa or less is applied, and if it is heating with heated nitrogen, the water in the nitrogen is excluded and reused to discharge condensed water. . This also reduces the oxygen concentration in the system, and simultaneously prevents oxidative degradation and thermal oxidative degradation.

  A release agent and a lubricant, a pigment, an antistatic agent, a flame retardant, a filler and the like can be added by a solid phase polymerization machine at any timing before solid phase polymerization or after completion of solid phase polymerization. .

The polyamide resin composition of the present invention is a black original polyamide pellet having a carbon black concentration of 12.5 wt% to 20.0 wt%. The concentration range of carbon black is preferably 12.5 wt% to 18.0 wt%, and the pellets can be obtained by spinning the pellets by a usual method. Further, it can be mixed and spun with the same type of polyamide pellets at an arbitrary ratio to form filaments or staples.

  In the polyamide resin composition of the present invention, other additives can be blended depending on the application within a range not impairing the effects of the present invention. These additives can be added to the monomer raw material, added during polymerization of the polyamide polymer, or blended by melt mixing with the copolymerized polyamide resin composition. In the case of melt mixing, melt mixing can also be performed using an extruder. Furthermore, base pellets containing these additives may be blended by chip blending or physically mixed with pellets of the copolymerized polyamide resin composition and then subjected to molding such as spinning, extrusion molding, injection molding and the like.

  Since the polyamide resin composition of the present invention has suppressed carbon black aggregation in the polymer, when blended with base pellets and melt-spun, the increase in filtration pressure is suppressed, and stable continuous operation can be performed for a long period of time, resulting in good spinning performance. Can be obtained.

  Hereinafter, the present invention will be specifically described with reference to examples. In the examples, the sulfuric acid relative viscosity, the filtration pressure increase ΔP and the like were measured by the following methods.

(1) Sulfuric acid relative viscosity (ηr)
The pellets were pulverized, JIS standard sieve 24 mesh passed, 124 mesh non-passed powder was collected, about 20 g of the powder was Soxhlet extracted with 200 ml of methanol for 3 hours, and the residue was dried and used as a measurement sample. Measurement was performed using an Ostwald viscometer at a concentration of 0.01 g / ml of a sample in 98% sulfuric acid at 25 ° C.

(2) Filtration pressure rise ΔP
A test spinning machine equipped with a melter that can automatically control the melting temperature and a pump (gear pump) that can dispense molten polymer in a fixed amount, a device that can continuously supply pellets, and a melter supply tank (residence time: about 15 minutes) that can be purged with nitrogen The melting temperature is set to 260 ° C. in advance and heated. Next, the black original master pellets dried in advance to a moisture content of 300 ppm or less and N6 polyamide not containing carbon black previously dried to a moisture content of 300 ppm or less were uniformly blended to obtain a carbon black concentration of 2.5 wt%. Prepared pellets and put them into the pellet charging port. Next, the rotation speed of the gear pump was adjusted so that the discharge polymer amount was 4.8 g / min. A 25-hole (φ2 mm) die (inserted with a replaceable sintered stainless steel filter (aperture 5 μm, filtration area 3.14 cm ² ) was inserted for 2 hours to clean the remaining polymer and replace the polymer in the melter. (Preheating at 280 ° C.) was attached to the downstream side of the gear pump, and spinning was performed for 11 hours while automatically recording the pressure between the gear pump and the base filter. The pressure when 1 hour has elapsed from the start of pressure recording is P ₀ , the pressure when 10 hours have elapsed is P _1, and the difference between P ₀ and P ₁ (P ₁ -P ₀ ) is the filtration pressure increase ΔP [MPa / 10 hr].

(3) Particle size distribution The particle size distribution of the polyamide monomer raw material solution was measured using a laser diffraction / scattering particle size distribution measuring apparatus (HORIBA LA950). In addition, the average particle diameter used the arithmetic average diameter (micrometer), and each particle diameter ratio used the passage integrated value (%).

(4) Content of carbon black About 5 g of polyamide pellets are pulverized under dry ice in a pulverizer, and uniform particles remaining at 36 mesh are collected. The collected sample is dried for 50 minutes in an electric constant temperature dryer at 105 ± 3 ° C. After cooling to room temperature in a desiccator, take a sample of 0.0250 ± 0.001 g with a balance in a 50 ml conical flask with a stopper and infiltrate with a permeator for 90 minutes at room temperature. After osmotic dissolution, spectrophotometer The absorbance is measured using a phenol / ethyl alcohol mixed solution as a target solution (wavelength: 610 nm, 10 mm glass cell), and the carbon black content is obtained from a known calibration curve obtained separately.

(5) Moisture content of polyamide pellets Measured using a Karl Fischer measuring device (vaporizer: SE-24 type, electrolytic cell: AQ-6 type) manufactured by Hiranuma Sangyo Co., Ltd. The sample was 3 g, and the nitrogen used for water vaporization was 220 ° C. and 200 ml / min.

(6) Moisture content in polyamide monomer The moisture content was calculated from the pure substance amount ratio in the polyamide raw material monomer solution. The water content after concentration was calculated from the weight reduction rate from the pre-concentration time after liquefying all of the water distilled out of the system by concentration through a condenser.

(7) Yarn-making property (number of yarn breaks)
A master chip was produced and dried by a conventional method so that the water content was 300 ppm or less. The obtained carbon black-containing master pellets and pellets not containing carbon black were blended so that the carbon black content was 2.5 wt%, melted at a melting temperature of 265 ° C., and a polymer having 25 stages of static mixers installed. It was passed through a pipe, filtered through a spinning pack provided with a 10 μm cut metal filter, and discharged from a spinneret at a spinning temperature of 260 ° C. As the spinneret, one having 68 holes, a round shape, and one yarn / base was used. After discharging from the spinneret, after cooling and refueling with cold air at 18 ° C., entanglement is performed, and then stretched 1.2 times through the first and second godded rolls at a winding speed of 4,000 m / min. Winding was performed to obtain a black original yarn of 96 dtex and 68 filaments. When the number of yarn breakage per ton of the obtained black original yarn was 4 or less, it was judged that the yarn forming property was good.

Example 1
(Raw material adjustment)
Into a polymerization reactor having a capacity of 5 liters, 1172 g of 87 wt% ε-caprolactam and 857 g of water slurry (oil furnace black) prepared in advance and having a carbon black concentration of 21 wt% were charged and mixed by stirring for 1 hour. The ratio of the carbon black average particle size of 0.16 μm and the average particle size of 0.2 μm or less at this time was 80% of the total, and the water content of the polyamide monomer raw material solution at this time was 41%.

  (Concentration) Next, the inside of the polymerization can was sealed, and after sufficiently purging with nitrogen, the heating medium was heated while stirring and the polyamide monomer raw material solution was concentrated (concentration step). At this time, while the heating medium heating temperature was controlled to 200 ° C. and the internal pressure of the can (gauge pressure) to 0.2 MPa, the raw material concentration in the polyamide monomer raw material solution was 85 wt% and the water content was 15 wt%. The concentration of the polyamide monomer raw material solution in the can was judged from the amount of distilled water.

  (Polymerization) Thereafter, the temperature was raised until the internal pressure of the polymerization reactor became 0.98 MPa, and the temperature was continuously raised to 250 ° C. while maintaining the internal pressure. After reaching 250 ° C., the pressure was released until atmospheric pressure was reached over 40 minutes. Then, after maintaining at 250 ° C. for 180 minutes at atmospheric pressure, the polymer was discharged and cooled / cut to form pellets.

(Extraction) Unreacted components in the pellets were extracted with 20 times the amount of hot water of 98 ° C. with respect to the pellets, and dried with a vacuum dryer to obtain black original nylon 6 pellets. The obtained black original nylon 6 master pellets had a ηr of 1.6 and a carbon black concentration of 15.0 wt%.
The produced black original nylon 6 master pellets were mixed with nylon 6 pellets (ηr2.6, containing 0.02 wt% of titanium oxide), blended to a carbon black concentration of 2.5 wt%, and yarn-formed. Table 1 shows the filtration pressure increase ΔP and the evaluation results of the yarn-making property.

Example 2
(Raw material adjustment) 1172 g of 87 wt% ε-caprolactam and 857 g of a previously prepared water slurry (oil furnace black) having a carbon black concentration of 21 wt% were charged into a polymerization reactor having a capacity of 5 liters and mixed by stirring for 1 hour. At this time, the ratio of the carbon black average particle size of 0.16 μm and the average particle size of 0.2 μm or less was 80% of the total, and the water content in the polyamide monomer raw material solution at this time was 41%.

  (Concentration) Next, the inside of the polymerization can was sealed, and after sufficiently purging with nitrogen, the heating medium was heated while stirring and the polyamide monomer raw material solution was concentrated (concentration step). At this time, while the heating medium heating temperature was controlled to 180 ° C. and the can internal pressure (gauge pressure) was controlled to 0.1 MPa, the raw material concentration in the polyamide monomer raw material solution was 85 wt% and the water content was 15 wt%. The concentration of the aqueous solution in the can was judged from the amount of distilled water.

  Raw material adjustment, polymerization, and extraction other than the concentration step were performed in the same manner as in Example 1 to obtain black original nylon 6 pellets with ηr: 1.6 and carbon black concentration: 15.0 wt%. Table 1 shows the filtration pressure increase ΔP and the evaluation results of the yarn-making property.

Example 3
(Raw material adjustment) 1172 g of 87 wt% ε-caprolactam and 857 g of a previously prepared water slurry (oil furnace black) having a carbon black concentration of 21 wt% were charged into a polymerization reactor having a capacity of 5 liters and mixed by stirring for 1 hour. At this time, the ratio of the carbon black average particle size of 0.12 μm and the average particle size of 0.2 μm or less was 83% of the total, and the water content in the polyamide monomer raw material solution at this time was 41%.

  (Concentration) Next, the inside of the polymerization can was sealed, and after sufficiently purging with nitrogen, the heating medium was heated while stirring and the polyamide monomer raw material solution was concentrated (concentration step). At this time, while controlling the heating medium heating temperature to 130 ° C. and the internal pressure (gauge pressure) to −0.06 MPa, the raw material concentration in the polyamide monomer raw material solution was 85 wt% and the water content was 15 wt%. . The concentration of the aqueous solution in the can was judged from the amount of distilled water.

  Raw material adjustment, polymerization, and extraction other than the concentration step were performed in the same manner as in Example 1 to obtain black original nylon 6 pellets with ηr: 1.6 and carbon black concentration: 15.0 wt%. Table 1 shows the filtration pressure increase ΔP and the evaluation results of the yarn-making property.

Example 4
(Raw material adjustment) 1103 g of 87 wt% ε-caprolactam and 1143 g of water slurry (oil furnace black) prepared in advance were mixed in a polymerization reactor having a capacity of 5 liters and mixed by stirring for 1 hour. At this time, the ratio of the average particle diameter of carbon black of 0.15 μm and the average particle diameter of 0.2 μm or less was 81% of the total, and the water content in the polyamide monomer raw material solution at this time was 47%.

  Concentration, polymerization, and extraction other than raw material adjustment were performed in the same manner as in Example 1 to obtain black original nylon 6 pellets having a ηr of 1.5 and a carbon black concentration of 20.0 wt%. Table 1 shows the filtration pressure increase ΔP and the evaluation results of the yarn-making property.

Example 5
(Raw material adjustment) 1103 g of 87 wt% ε-caprolactam and 1143 g of water slurry (oil furnace black) prepared in advance were mixed in a polymerization reactor having a capacity of 5 liters and mixed by stirring for 1 hour. The ratio of the carbon black average particle diameter of 0.20 μm and the average particle diameter of 0.2 μm or less at this time was 65% of the total, and the moisture in the polyamide monomer raw material solution at this time was 47%.
Concentration, polymerization, and extraction other than raw material adjustment were performed in the same manner as in Example 1 to obtain black original nylon 6 pellets having a ηr of 1.5 and a carbon black concentration of 20.0 wt%. Table 1 shows the filtration pressure increase ΔP and the evaluation results of the yarn-making property.

Example 6
(Raw material adjustment) 1207 g of 87 wt% ε-caprolactam and 714 g of water slurry (oil furnace black) prepared in advance with a carbon black concentration of 21 wt% were charged in a 5 liter polymerization reactor and mixed by stirring for 1 hour. At this time, the ratio of the carbon black average particle diameter of 0.14 μm and the average particle diameter of 0.2 μm or less was 83% of the total, and the moisture in the polyamide monomer raw material solution at this time was 38%.

  Concentration, polymerization, and extraction other than raw material adjustment were performed in the same manner as in Example 1 to obtain black original nylon 6 pellets having ηr of 1.9 and a carbon black concentration of 12.5 wt%. Table 1 shows the filtration pressure increase ΔP and the evaluation results of the yarn-making property.

Example 7
(Preparation of raw materials) In a polymerization reactor having a capacity of 5 liters, 1925 g of 53 wt% AH salt and 155 g of carbon black (oil furnace black) were charged and mixed by stirring for 1 hour. The ratio of the carbon black average particle size of 0.16 μm and the average particle size of 0.2 μm or less at this time was 73% of the total, and the moisture in the polyamide monomer raw material solution at this time was 44%.

  (Concentration) Next, the inside of the polymerization can was sealed, and after sufficiently purging with nitrogen, the aqueous medium was concentrated by heating the heating medium while stirring (concentration step). At this time, while the heating medium heating temperature was controlled to 200 ° C. and the can internal pressure (gauge pressure) to 0.2 MPa, the solution was concentrated until the concentration of the raw material in the aqueous solution became 85 wt% (water content after concentration: 15%). The concentration of the aqueous solution in the can was judged from the amount of distilled water.

  (Polymerization) Thereafter, the temperature was raised until the internal pressure of the polymerization reactor reached 1.70 MPa, and the temperature was continued to 255 ° C. while maintaining the internal pressure of the can. After reaching 255 ° C., the pressure was released until atmospheric pressure was reached over 50 minutes. After that, the heating temperature is adjusted so that the temperature of the polymer at the end of decompression is 280 ° C, the pressure in the can (gauge pressure) is reduced to -13 kPa and maintained for 5 minutes, the polymer is discharged, cooled / cut, and pelletized I made it. The obtained black original nylon 66 master pellets had a ηr of 2.1 and a carbon black concentration of 15.0 wt%.

  The produced black original nylon 66 master pellets were mixed with nylon 6 pellets (ηr2.6, containing 0.02 wt% of titanium oxide), blended to a carbon black concentration of 2.5 wt%, and then made into yarn. Table 1 shows the filtration pressure increase ΔP and the evaluation results of the yarn-making property.

Example 8
(Raw material adjustment) 1172 g of 87 wt% ε-caprolactam and 857 g of a carbon black concentration 21 wt% water slurry (channel black) prepared in advance were charged into a polymerization reactor having a capacity of 5 liters and mixed by stirring for 1 hour. At this time, the ratio of the carbon black average particle diameter of 0.14 μm and the average particle diameter of 0.2 μm or less was 82% of the total, and the moisture in the polyamide monomer raw material solution at this time was 41%. Concentration, polymerization, and extraction other than raw material adjustment were performed in the same manner as in Example 1 to obtain black original nylon 6 pellets having a ηr of 1.7 and a carbon black concentration of 15.0 wt%. Table 1 shows the filtration pressure increase ΔP and the evaluation results of the yarn-making property.

Example 9
(Raw material preparation) 1229 g of 83 wt% ε-caprolactam and 180 g of carbon black (oil furnace black) were charged into a polymerization reactor having a capacity of 5 liters and mixed by stirring for 1 hour. At this time, the ratio of the carbon black average particle size of 0.19 μm and the average particle size of 0.2 μm or less was 67% of the total, and the water content in the polyamide monomer raw material solution at this time was 15%.

  (Concentration) Next, the inside of the polymerization can was sealed, and after sufficiently purging with nitrogen, the heating medium was heated while stirring and the polyamide monomer raw material solution was concentrated (concentration step). At this time, while the heating medium heating temperature was controlled to 200 ° C. and the internal pressure of the can (gauge pressure) to 0.2 MPa, the raw material concentration in the polyamide monomer raw material solution was 90% by weight and the water content was 10% by weight. The concentration of the aqueous solution in the can was judged from the amount of distilled water.

  Polymerization and extraction other than the raw material adjustment and concentration steps were performed in the same manner as in Example 1 to obtain black original nylon 6 pellets having a ηr of 1.7 and a carbon black concentration of 15.0 wt%. Table 2 shows the evaluation results of the degree of filtration pressure increase ΔP and yarn production.

Example 10
(Raw material adjustment) In a polymerization reactor having a capacity of 5 liters, 1325 g of 77 wt% ε-caprolactam and 180 g of carbon black (oil furnace black) were charged and mixed by stirring for 1 hour. At this time, the ratio of the carbon black average particle size of 0.17 μm and the average particle size of 0.2 μm or less was 72% of the total, and the water content in the polyamide monomer raw material solution at this time was 20%.

  (Concentration) Next, the inside of the polymerization can was sealed, and after sufficiently purging with nitrogen, the heating medium was heated while stirring and the polyamide monomer raw material solution was concentrated (concentration step). At this time, while the heating medium heating temperature was controlled to 200 ° C. and the internal pressure of the can (gauge pressure) to 0.2 MPa, the raw material concentration in the polyamide monomer raw material solution was 90% by weight and the water content was 10% by weight. The concentration of the aqueous solution in the can was judged from the amount of distilled water.

  Polymerization and extraction other than the raw material adjustment and concentration steps were performed in the same manner as in Example 1 to obtain black original nylon 6 pellets with ηr: 1.6 and carbon black concentration: 15.0 wt%. Table 2 shows the evaluation results of the degree of filtration pressure increase ΔP and yarn production.

Example 11
(Raw material adjustment) 1172 g of 87 wt% ε-caprolactam and 1242 g of water slurry (oil furnace black) prepared in advance and charged in a 5 liter polymerization reactor were mixed by stirring for 1 hour. The ratio of the carbon black average particle diameter of 0.15 μm and the average particle diameter of 0.2 μm or less at this time was 79% of the whole, and the water content in the polyamide monomer raw material solution at this time was 50%.

  (Concentration) Next, the inside of the polymerization can was sealed, and after sufficiently purging with nitrogen, the heating medium was heated while stirring and the polyamide monomer raw material solution was concentrated (concentration step). At this time, while the heating medium heating temperature was controlled to 180 ° C. and the internal pressure (gauge pressure) was controlled to 0.2 MPa, the raw material concentration in the polyamide monomer raw material solution was 80 wt% and the water content was 20 wt%. The concentration of the aqueous solution in the can was judged from the amount of distilled water.

  Polymerization and extraction other than the raw material adjustment and concentration steps were performed in the same manner as in Example 1 to obtain black original nylon 6 pellets with ηr: 1.6 and carbon black concentration: 15.0 wt%. Table 2 shows the evaluation results of the degree of filtration pressure increase ΔP and yarn production.

Example 12
(Raw material adjustment) Into a polymerization reactor with a capacity of 5 liters, 1172 g of 87 wt% ε-caprolactam and a water slurry (oil furnace black) having a carbon black concentration of 10 wt% prepared in advance were charged and mixed by stirring for 1 hour. The proportion of the carbon black average particle size of 0.14 μm and the average particle size of 0.2 μm or less at this time was 81% of the total, and the water content in the polyamide monomer raw material solution at this time was 60%.

  (Concentration) Next, the inside of the polymerization can was sealed, and after sufficiently purging with nitrogen, the heating medium was heated while stirring and the polyamide monomer raw material solution was concentrated (concentration step). At this time, while the heating medium heating temperature was controlled to 170 ° C. and the can internal pressure (gauge pressure) was controlled to 0.2 MPa, the raw material concentration in the polyamide monomer raw material solution was concentrated to 70 wt% and the water content was 30 wt%. The concentration of the aqueous solution in the can was judged from the amount of distilled water.

  Polymerization and extraction other than the raw material adjustment and concentration steps were performed in the same manner as in Example 1 to obtain black original nylon 6 pellets with ηr: 1.6 and carbon black concentration: 15.0 wt%. Table 2 shows the evaluation results of the degree of filtration pressure increase ΔP and yarn production.

Example 13
The black original nylon 6 master pellets obtained in Example 1 were subjected to solid phase polymerization at 170 ° C. for 12 hours in a vacuum dryer to obtain ηr2.5 black original nylon 6 pellets.
The produced black original nylon 6 master pellets were mixed with nylon 6 pellets (ηr2.6, containing 0.02 wt% of titanium oxide), blended to a carbon black concentration of 2.5 wt%, and yarn-formed. Table 2 shows the evaluation results of the degree of filtration pressure increase ΔP and yarn production.

Comparative Example 1
(Raw material adjustment) 1035 g of 87 wt% ε-caprolactam and a water slurry (oil furnace black) having a carbon black concentration of 21 wt% prepared in advance were charged in a polymerization reactor having a capacity of 5 liters and mixed by stirring for 1 hour. At this time, the ratio of the carbon average particle diameter of 0.22 μm and the average particle diameter of 0.2 μm or less was 62% of the total, and the water content in the polyamide monomer raw material solution at this time was 53%.

  (Polymerization) Next, the inside of the polymerization vessel was sealed, sufficiently purged with nitrogen, and then stirred, the temperature was raised until the internal pressure of the reactor became 0.98 MPa, and the temperature was continuously raised to 250 ° C. while maintaining this pressure. It was. After reaching 250 ° C., the pressure was released until atmospheric pressure was reached over 40 minutes. Then, after maintaining at 250 ° C. for 180 minutes at atmospheric pressure, the polymer was discharged and cooled / cut to form pellets.

(Extraction) Unreacted components in the pellets were extracted with 20 times the amount of hot water of 98 ° C. with respect to the pellets, and dried with a vacuum dryer to obtain black original nylon 6 pellets. The obtained black original master pellets had a ηr of 1.3 and a carbon black concentration of 25.0 wt%.
The produced black original master pellets were mixed with N6 pellets (ηr2.6, containing 0.02 wt% titanium oxide), blended so as to have a carbon black concentration of 2.5 wt%, and formed into yarns. Table 2 shows the evaluation results of the degree of filtration pressure increase ΔP and yarn production.

  In Comparative Example 1, in which the monomer raw material solution was not concentrated before the polymerization and the polymerization was performed in a state where the water content was 53%, ΔP was as high as 1.5 MPa, resulting in poor yarn production.

Comparative Example 2
(Raw material adjustment) 1172 g of 87 wt% ε-caprolactam and 857 g of a previously prepared water slurry (oil furnace black) having a carbon black concentration of 21 wt% were charged into a polymerization reactor having a capacity of 5 liters and mixed by stirring for 1 hour. At this time, the ratio of the carbon black average particle size of 0.16 μm and the average particle size of 0.2 μm or less was 73% of the total, and the water content in the monomer at this time was 44%. Polymerization and extraction other than raw material adjustment were carried out in the same manner as in Comparative Example 1 to obtain black original nylon 6 pellets with ηr: 1.6 and carbon black concentration: 15.0 wt%. Table 2 shows the evaluation results of the degree of filtration pressure increase ΔP and yarn production.

  In Comparative Example 2, in which the monomer raw material solution was not concentrated before the polymerization and the polymerization was performed in a state where the moisture content was 41%, ΔP was as high as 1.4 MPa, resulting in inferior spinning properties.

Comparative Example 3
(Raw material adjustment) Into a polymerization reactor with a capacity of 5 liters, 1172 g of 87 wt% ε-caprolactam and a water slurry (oil furnace black) having a carbon black concentration of 10 wt% prepared in advance were charged and mixed by stirring for 1 hour. At this time, the ratio of the carbon black average particle diameter of 0.14 μm and the average particle diameter of 0.2 μm or less was 81% of the total, and the water content in the monomer at this time was 60%.

  (Concentration) Next, the inside of the polymerization can was sealed, and after sufficiently purging with nitrogen, the heating medium was heated while stirring and the polyamide monomer raw material solution was concentrated (concentration step). At this time, while the heating medium heating temperature was controlled to 170 ° C. and the can internal pressure (gauge pressure) was controlled to 0.2 MPa, the raw material concentration in the polyamide monomer raw material solution was concentrated to 65 wt% and the moisture content was 35 wt%. The concentration of the aqueous solution in the can was judged from the amount of distilled water.

Polymerization and extraction other than the raw material adjustment and concentration steps were performed in the same manner as in Comparative Example 1 to obtain black original nylon 6 pellets with ηr: 1.6 and carbon black concentration: 15.0 wt%. Table 2 shows the evaluation results of the degree of filtration pressure increase ΔP and yarn production.
In Comparative Example 3 in which the polymerization was carried out in a state where the moisture content was 35% after the concentration, ΔP was as high as 1.1 MPa, resulting in poor yarn production.

Claims (2)

  Filtration pressure increase ΔP with a 5 μm filter when carbon black concentration is 12.5 wt% to 20.0 wt% black original deposition master pellet blended with base pellet to make carbon black concentration 2.5 wt% [MPa / 10 hr] is 1.0 or less, polyamide resin composition characterized by the above-mentioned.   When producing a polyamide resin composition having a carbon black concentration of 12.5 wt% to 20.0 wt% by polycondensation reaction of the polyamide monomer raw material solution, an average particle size is added to the polyamide monomer raw material solution having a moisture concentration of 15 wt% to 60 wt%. As a polyamide monomer raw material solution having a water concentration of 10 wt% to 30 wt%, added to 12.5 wt% to 20.0 wt% to a polyamide resin composition capable of obtaining 0.1 μm to 0.2 μm carbon black, A method for producing a polyamide resin composition, comprising subjecting the polyamide monomer raw material solution to a polycondensation reaction.