JP2017048258A - Copolymer polyamide excellent in color tone and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide copolymer polyamide excellent in color tone and small in low polymer amount in the polymer, especially copolymer polyamide excellent in operability during forming a fiber, hardly reducing adhesive force over long time and suitable for a hot melt type adhesive.SOLUTION: There is provided a polyamide pellet manufactured by copolymerizing 2 or more kinds of monomers and having melting peak temperature (Tm) measured based on JIS K 7121 of 130°C or less, yellow intensity YI of -2.0 or less and low polymerization component soluble in hot water at 60°C of 2.0 wt.% or less.SELECTED DRAWING: None

Description

  The present invention relates to a copolyamide having excellent color tone and a small amount of low polymer in the polymer.

  Polyamides typified by polycaproamide and polyhexamethylene adipamide are excellent in physical properties and chemical resistance, and are therefore widely used in engineering plastics, clothing and industrial textile applications.

  In addition to these applications, a copolymer polyamide having a specific melting point is also used as a hot-melt adhesive that melts by heat treatment and bonds the materials together.

  For example, a copolymerized polyamide obtained by copolymerizing three or more monomers and having a melting point in the range of 80 to 130 ° C., and pellets and fibers thereof have been proposed (Patent Documents 1 and 2).

  Patent Document 1 describes a method for producing a quaternary copolymerized polyamide having a melting point in the range of 80 to 130 ° C. Regarding the problem of pellet fusion, which is a problem of a low melting point polymer, 10 to 80 ° C. The method of crystallizing the surface of a pellet by treating with water and inhibiting blocking is described. With this technology, it is possible to prevent the pellets from fusing together, and a stable supply to the post-processing process becomes possible.

  However, since polyamide polymers contain monomers and low polymers, the spinning operation is increased by the fact that low polymers deposited on the fiber surface in the process of melt spinning to obtain fibers accumulate on the spinning machine, resulting in increased yarn breakage. And the yield deteriorates. In order to improve it, Patent Document 2 describes that a copolymerized polyamide having excellent yarn-manufacturability can be obtained by reducing low polymer by extraction with warm water.

  Although this technique can solve the problem of deterioration of the yarn production operation due to the low polymer, the polyamide pellets are colored during the hot water extraction, and the color tone of the yarn produced is also deteriorated. Since the colored thread cannot be applied to uncolored or light-colored materials, there remains a problem of improving the color tone of the polymer.

Japanese Patent Laid-Open No. 11-12364 Japanese Patent No. 5716452

  An object of the present invention is to provide a copolyamide having an excellent color tone and a low amount of low polymer in a polymer, and in particular, a hot melt type that is excellent in operability at the time of fiber formation and has a low adhesive strength over a long period of time. It is an object of the present invention to provide a copolymerized polyamide that can be suitably used for an adhesive.

In order to solve the above problems, the present invention has the following configuration.
(1) A copolymerized polyamide obtained by copolymerizing two or more monomers and having a melting peak temperature (Tm) measured in accordance with JIS K 7121 of 130 ° C. or lower, and the yellowing degree YI of the polyamide pellet is −2 Copolyamide pellets characterized in that the low polymerization component soluble in 60 ° C. hot water is 2.0% by weight or less.
(2) The copolymerized polyamide pellet according to claim 1, wherein the monomer to be copolymerized is an aliphatic monomer.
(3) The two or more types of monomers are at least two types selected from a monomer constituting polycaproamide, a monomer constituting polyhexamethylene adipamide, and a monomer constituting polydodecanamide. Copolymer polyamide pellets according to claim 1 or 2.
(4) When producing a copolymerized polyamide having a melting peak temperature (Tm) measured in accordance with JIS K 7121 of 130 ° C. or lower, obtained by copolymerizing two or more monomers, 60 ° C. hot water in the polyamide after polymerization In the process of reducing the low polymer soluble in water by hot water extraction, the maximum temperature of the hot water to be treated is (Tm-40 ° C.) or less, and the amount of dissolved air is 1 L of hot water to be treated. It is 15 mL or less, The manufacturing method of the copolyamide pellet of any one of Claims 1-3 characterized by the above-mentioned.
(5) When producing a copolymerized polyamide having a melting peak temperature (Tm) measured in accordance with JIS K 7121 of 130 ° C. or less, obtained by copolymerizing two or more types of monomers, 60 ° C. hot water in the polyamide after polymerization In the process of reducing the low polymer soluble in water by hot water extraction, the maximum temperature of the hot water to be treated is (Tm−40 ° C.) or less, and pellets floating on the hot water surface are allowed to settle in water. The method for producing a copolymerized polyamide pellet according to any one of claims 1 to 3.

  According to the present invention, it is possible to obtain a copolyamide having excellent color tone and a small amount of low polymer in the polymer, particularly excellent in operability at the time of fiber formation and having a low adhesive strength over a long period of time. A copolyamide suitable for the above can be obtained.

  The copolymerized polyamide of the present invention is a resin in which a plurality of types of monomers are linked by a so-called amide bond. By setting it as this structure, the melting point of a polymer can be reduced and the copolyamide suitable for a hot-melt-type adhesive agent can be obtained. As for the number of monomers to be constituted, if it is 2 or more, it can be lowered to a polymer melting point that can be used for thermal bonding, and preferably 3 or more. Further, by using four or more types, it is possible to produce a polymer having a lower melting point, which is useful for applications requiring thermal bonding at a low temperature.

  Although there is no restriction | limiting in particular as a structure of a monomer, The effect of the dispersion | distribution of an internal stress distortion at the time of an adhesive processing and the improvement of a flexibility is acquired, and the outstanding adhesive strength can be expressed, including at least 1 or more aliphatic monomer It is preferable from the point.

  Monomers constituting the copolymerized polyamide include lactam or aminocarboxylic acid, polytetramethylene adipamide, polypentamethylene adipamide, polypentamethylene sebaca constituting polycaproamide, polyundecanamide, polydodecanamide and the like. Dicarboxylic acids and diamines constituting amide, polyhexamethylene adipamide, polyhexamethylene sebamide, polyhexamethylene dodecanamide, polyhexamethylene tridecanamide, polyhexamethylene terephthalamide, polyhexamethylene isophthalamide, etc. And ε-caprolactam constituting polycaproamide or 6-aminocaproic acid and hexamethylene diammonium adipate constituting polyhexamethylene adipamide (AH). ), Hexamethylene diammonium sebacate constituting the polyhexamethylenesebacamide (SH salts), it is particularly preferred that it include a ω- laurolactam or 12-aminododecanoic acid constituting the polydodecanamide.

  Among these, ε-caprolactam constituting polycaproamide or 6-aminocaproic acid, hexamethylene diammonium adipate (AH salt) constituting polyhexamethylene adipamide, and ω-laurolactam constituting polydodecanamide Alternatively, it is preferable to contain one or more of 12-aminododecanoic acid from the viewpoint of stable commercial availability, and from the viewpoint of balance with easy control of the melting peak temperature, ε-caprolactam or 6- It is particularly preferable to include three kinds of amino caproic acid, hexamethylene diammonium adipate (AH salt) constituting polyhexamethylene adipamide, and ω-laurolactam or 12-aminododecanoic acid constituting polydodecanamide.

  Other monomers to be combined with the above monomers are preferably hexamethylene diammonium sebacate (SH salt) constituting polyhexamethylene sebacamide, ω-undecanactam or 11-aminoundecanoic acid constituting polyundecanamide. .

  When the monomer includes at least three monomers, ie, a monomer constituting polycaproamide, a monomer constituting polyhexamethylene adipamide, and a monomer forming polydodecanamide, these monomers constituting polycaproamide, polyhexamethylene azide It is preferable that the total monomer ratio of the monomer constituting the pamide and the monomer forming the polydodecanamide is 50 to 100% by weight, and more preferably 60 to 100% by weight. When the total monomer ratio is less than 50% by weight, depending on the combination of other monomers constituting the copolymerized polyamide, the high elongation of the copolymerized polyamide fiber of the present invention is reduced, and higher orders of weaving, knitting, etc. When subjected to processing, thread breakage and raw yarn fluff may occur and stable high-order processing may not be realized.

  Regarding the individual monomer ratio, the monomer constituting polycaproamide is 30 to 60% by weight, the monomer constituting polyhexamethylene adipamide is 10 to 30% by weight, and the monomer forming polydodecanamide is 10 to 30% by weight. %, And other polyamide-forming monomers are each selected from 0 to 50% by weight, and the total amount is particularly preferably 100% by weight. Within such a range, it is easy to control the melting peak temperature of the copolymerized polyamide of the present invention within the range of the present invention. For example, applications that require adhesive strength at relatively low temperatures such as irons (for trousers) When used for a hemming tape, etc., it is possible to maintain good adhesive strength.

  The melting point of the copolymerized polyamide of the present invention, which is suitable as a hot melt adhesive, has a melting peak apex temperature (Tm) measured in accordance with JIS K 7121 (1987) of 130 ° C. or lower. Copolymer polyamide having an arbitrary melting point of 130 ° C. or lower is used depending on the intended use, but it is preferably 110 ° C. or lower from the viewpoint of minimizing the heat history applied to the product in the thermal bonding process and suppressing thermal deterioration and discoloration of the product. 80 ° C. or lower is more preferable. Since it is necessary to maintain adhesiveness under the temperature conditions generally used, it is preferable to have a melting point of 60 ° C. or higher.

  Nylon polymer after polymerization contains a certain amount of monomer and low polymer due to the influence of polymerization equilibrium, and generally the monomer and low polymer in the polymer are reduced by extraction with hot water. However, the melting point of the copolymerized polyamide of the present invention is 130 ° C. or lower, and when extraction is performed using hot water at 100 ° C., the polymer softens or melts and the pellets are fused. In order to avoid fusion, there is a method of performing extraction treatment for a long time by lowering the temperature of the extraction water, but until the content of the monomer and low polymer is reduced to the extent that the operability during fiber formation is excellent, Since it is necessary to treat with warm water for a long time, the color tone of the pellet is deteriorated due to thermal degradation of the polymer in the extraction process or degradation due to contact with oxygen.

  Also, when extracting with hot water, the amount of air contained in the water is reduced because the extracted water once boils, but when treated with hot water of 90 ° C. or less, the amount of air contained in the water is large. Therefore, coloring by contact with oxygen is promoted.

  There is a method to decompose the dissolved oxygen in the water by adding a reducing agent such as hydrazine to the extracted water as a method to suppress the deterioration of the color tone of the pellets, but the hydrazine compound is not added from the point of health hazard It is hoped that.

  As a method for extracting pellets, there are a continuous extraction method, a batch type extraction, and the like, but there is no particular limitation. However, the copolyamide of the present invention has a low melting point and is easy to be fused, and unextracted polyamide pellets are more easily melted and fused due to the plasticizing effect of the monomer and low polymer, so It is desirable to start the extraction. The initial extraction water temperature is Tm-60 ° C or lower, preferably Tm-70 ° C or lower. As a minimum of water temperature, it is 0 degreeC or more which is a freezing point.

  On the other hand, it is desirable that the extraction water temperature is higher in terms of extraction efficiency. Therefore, the temperature is increased stepwise from the beginning of extraction. In order to produce a polyamide having excellent color tone and reduced low polymerization components according to the present invention, the extraction water temperature is preferably Tm-40 ° C. or lower. Moreover, it is more preferable from a viewpoint of color tone that extraction temperature shall be Tm-50 degrees C or less. Since the extraction time is extended when the water temperature is low, the lower limit of the water temperature is preferably 30 ° C. or higher.

  Low polymers such as monomers and oligomers contained in the polyamide are gasified and scattered during melt spinning, which causes surface contamination of the spinneret and deteriorates operability. The copolymerized polyamide of the present invention obtained by extraction is excellent in operability because of the small amount of low polymer. Specifically, it is necessary that the low polymer content is 2.0% by weight or less with a low polymer content detected by a hot water extraction method at 60 ° C. Preferably it is 1.5 weight% or less, More preferably, it is 1.0 weight% or less. Most preferred is 0.5% by weight or less.

  Moreover, about extraction time, it carries out until it becomes a desired low polymer content rate. Although it varies depending on the monomer constituting the copolymerized polyamide, the low polymer content in the copolymerized polyamide immediately after polymerization, the pellet shape, the bath ratio, the extraction temperature, etc., it is generally about 24 to 144 hours, preferably about 24 to 96 hours, Most preferably, it is about 24 to 72 hours.

  As described above, coloring is promoted when the amount of dissolved oxygen in the extraction water is large. However, the present invention is a polyamide having a Tm of 130 ° C. or lower and the extraction water temperature is set to Tm−40 ° C. or lower, that is, extraction. The water temperature is preferably 90 ° C. or lower.

  As a method for reducing the oxygen content in the extracted water without adding a reducing agent such as hydrazine, there is a method in which the extracted water is once boiled and then cooled.

  By performing this method, it is possible to suppress deterioration of the color tone of the pellets. Therefore, the air content in the extracted water is preferably 5 mL or less, more preferably 3 mL or less, with respect to 1 L of extracted water. is there. Although it is possible to lower the air content by boiling for a long time, it is economically preferable to set the lower limit to 0.5 mL.

  On the other hand, once the extracted water is boiled and then cooled and used, there is a large loss of energy to be used, which may be disadvantageous when applied in business. In that case, the cold water is heated and used. However, the lower the extraction water temperature, the higher the solubility of the air, so that air that cannot be completely dissolved by heating becomes bubbles and adheres to the pellets. Due to the air bubbles adhering to the pellets, the pellets float and come to the surface of the water, so that the pellets are exposed to a large amount of air, so that the color tone of the pellets is significantly deteriorated.

  In order to suppress the deterioration of the pellet color tone, it is effective to prevent the floated pellets from being exposed to the air on the surface of the water, and it is important to use equipment for sinking the floated pellets.

  If there is an effect to settle the pellet, there is no restriction on the use of the equipment, but the pellet in the extraction equipment is self-circulated as a water slurry, or a stirrer is installed at the top of the water surface to mechanically remove bubbles adhering to the pellet There is a technique to do.

  Since the polyamide pellet of the present invention suppresses the above-described deterioration and is excellent in color tone, it is advantageous for applications in which coloring is not performed in a post-processing step and for light-colored materials.

  The yellowing degree YI of the polyamide pellets needs to be −2.0 or less, and in a preferred embodiment, it is −3.5 or less. More preferably, it is -4.0 or less, and the lower limit is about -15.0.

  The copolymerized polyamide after completion of extraction preparation is preferably dried because it contains about 2 to 8% by weight of water. Examples of the method for drying the copolymerized polyamide pellets include a method of heating in a batch system under a reduced pressure of 1.3 kPa or less, or a method of continuously contacting the copolymerized polyamide pellets with heated nitrogen. The latter, which allows continuous operation, is advantageous when mass-producing copolymerized polyamide pellets, and the former is advantageous when producing small-quantity, multi-product. In normal cases, drying is preferably carried out at a temperature not higher than the melting point of the copolymerized polyamide for about 10 to 30 hours until the moisture content is approximately 0.1% by weight or less.

  The copolymer polyamide of the present invention may contain various additives as long as the effects of the present invention are not impaired. Examples of this additive include stabilizers such as manganese compounds, colorants such as titanium oxide, flame retardants, conductivity-imparting agents, and fibrous reinforcing agents. However, in inorganic particles such as titanium oxide, the adhesive strength tends to decrease when added in a large amount, and the preferred range of the content of the inorganic particles is preferably 0 to 5.0% by weight, more preferably 0 to 2% by weight. %, Most preferably 0 to 0.1% by weight.

  The copolymerized polyamide of the present invention is useful as a hot-melt type adhesive, and can be used in various forms such as a fiber type, a film type, and a powder type, and can be used for bonding fiber products, packaging materials, woodwork products, and the like. It is effective for. In particular, the fiber type is particularly useful when used for bonding fiber products.

  The fiber obtained from the copolymerized polyamide of the present invention may be a monofilament or a multifilament, but preferably a multifilament is used, and the single yarn fineness is preferably 1.5 to 5 dtex, more preferably 2 to 4 dtex. . By setting it as this structure, since each single yarn melt | dissolves completely and uniformly, the outstanding adhesive strength can be expressed. When the single yarn fineness is less than 1.5 dtex, the high elongation of the resulting filament is lowered, so that the high-order workability is deteriorated and the melt spinnability itself is also deteriorated. It cannot be produced. Conversely, if the single yarn fineness exceeds 5 dtex, even if the copolymer component and the melting peak temperature are within the specified range, each single yarn may not be melted uniformly, resulting in poor adhesive strength. It will be a thing.

  The strength of the fiber obtained from the copolymerized polyamide of the present invention is preferably 1.5 cN / dtex or more, more preferably 2 cN / dtex or more. When the strength is less than 1.5 cN / dtex, fluff and yarn breakage may occur in higher-order processes such as twisted yarn and knitting, and high-order passability may become unstable.

  In addition, the elongation of the fiber obtained from the copolymerized polyamide of the present invention is preferably in the range of 40 to 120%, and more preferably in the range of 60 to 100%. Such a range is the range that is most easily processed, and, for example, when the elongation is less than 40%, it is difficult to twist in the process of twisting such as when forming a mall yarn, Care must be taken because raw yarn fluff is likely to occur. Conversely, if the elongation exceeds 120%, the fiber structure is not stable, which may cause quality changes during storage or high-order processing, especially in warehouses with high temperatures and high humidity. Because it becomes conspicuous, attention is necessary.

  The single yarn cross-sectional shape of the fiber obtained from the copolymerized polyamide of the present invention may be appropriately selected in order to stably obtain the required characteristics of the fiber or a processed product thereof. Illustrative examples include a perfect circle, an ellipse, a trilobal, a four-leaf, a cross, a hollow, a flat, a T-shaped, an X-shaped, an H-shaped cross-section, etc. Is preferable from the viewpoint of melt spinnability and ease of spinning. Moreover, the fiber form can take various fiber product forms, such as a long fiber, a short fiber, a nonwoven fabric, and a thermoforming body.

  Examples of the textile products using the copolymerized polyamide of the present invention include decorative yarns (mall yarn) in which upright flower yarns are arranged and fixed by melt bonding, or fabrics are used with a domestic iron or the like. A so-called adhesive tape typified by a hemming tape to be bonded, a brush bristle portion used for a mop or the like as a yarn mixed with a part of a plurality of fibers and fixed in form by heat treatment, It can be used suitably for applications such as carpet pile yarn.

A method for producing the copolymerized polyamide of the present invention will be described.
The copolymerized polyamide of the present invention can be produced by any known polymerization method, but it is essential to carry out washing with warm water after polymerization to remove water-soluble components.

The polymerization method is exemplified below.
The polymerization and washing method can be produced by either a batch method or a continuous method, but the batch method is usually employed when various types of polymers having different melting points are produced according to needs.

An example of a batch production method will be described below.
First, the batch polymerization equipment will be described. When polymerizing the copolymerized polyamide, it is necessary to pressurize at the initial stage of polymerization, and a so-called autoclave is generally used for the reactor. In order to promote uniform heating and reaction, it is possible to equip the inside with a heating coil or a stirring blade.

  The maximum value of the pressure in the polymerization apparatus during the polymerization is adjusted by the boiling point of the monomer used, but usually 0.7 MPa or more is employed. When it is less than 0.7 MPa, the amount of evaporation of the monomer component increases, and the degree of polymerization of the copolymerized polyamide resin obtained by breaking the molar balance may be lowered. Although there is no particular upper limit, it is preferably 3.0 MPa or less, more preferably 2.0 MPa or less in consideration of the pressure resistance of the polymerization apparatus. As a method for discharging the polymer after completion of the polymerization, a method in which a polymerization apparatus is pressurized with an inert gas, the polymer extruded in a strand shape is cooled with water, and then cut to obtain pellets is preferably used. At this time, it is effective to stabilize the polymer quality by extruding the polymer in as short a time as possible, preferably within 1.5 hours, more preferably within 1 hour, and most preferably within 0.5 hour.

  As the viscosity number of the copolymerized polyamide resin obtained by the present invention, the lower the viscosity number, the better the permeability to the object to be bonded, and higher adhesive strength can be obtained. If it is too much, it is not preferable because it cannot be made into a strand or melt spinnability may be deteriorated. A preferable range of the viscosity number is 80 to 170 ml / g. The viscosity number was measured using an Ubbelohde viscometer in accordance with JIS-K6933 (1999) with 96% sulfuric acid as a solvent.

  The obtained pellets are usually stored at room temperature (30 ° C. or lower) for 24 hours or longer and then used for the extraction step. If the storage time is less than 24 hours and the extraction process is performed, the pellets may be fused together.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to a following example at all unless the summary is exceeded.

A. Amount of dissolved air in the extracted water The amount of dissolved oxygen and the amount of dissolved nitrogen in the extracted water were measured using a 6890 series (HP) gas chromatography, and the total amount of the two components was taken as the amount of dissolved air. Helium gas was used as the carrier gas. The amount of air is a value obtained by converting the volume when a gas at 1 atm is dissolved into the volume at 0 ° C. and 1 atm at the water temperature measured in the following examples.

B. Melting peak temperature It measured according to the differential scanning calorimetry (DSC) method of JIS-K7121 (1987). In addition, the Diamond DSC apparatus made from Perkin Elmer was used, and the temperature increase rate was 20 degrees C / min.

C. Low Polymer (MO) Content After pulverizing the sample (pellet), it is passed through a JIS standard sieve 35 mesh and 100 mesh sieve, and the powder that passes through 35 mesh and remains at 100 mesh is collected. The obtained powder is weighed after drying until the moisture content becomes 0.03% by weight or less, and the weight is defined as W1. The weighed powder is extracted with 60 ° C. warm water having a weight of 200 times or more with respect to the powder weight for 4 hours. The powder is washed with water, then dried and weighed again until the water content becomes 0.03% by weight or less, and the weight is defined as W2. Calculated from W1 and W2 by the following equation.
Low polymer (MO) content (% by weight) = (W1-W2) / W1 × 100.

D. Relative viscosity (ηr)
A sample of 0.25 g was dissolved to 1 g in 100 ml of sulfuric acid having a concentration of 98% by weight, and the flow time (T1) at 25 ° C. was measured using an Ostwald viscometer. Subsequently, the flow-down time (T2) of only 98% by weight sulfuric acid was measured. The ratio of T1 to T2, that is, T1 / T2, was defined as sulfuric acid relative viscosity.

E. Pellet color tone YI
The YI value of the pellet was measured using a color computer manufactured by Suga Test Instruments Co., Ltd. The measurement was performed according to JIS standard K7105 (plastic optical property test method).

Example 1
ε-caprolactam, equimolar salt of hexamethylenediamine and adipic acid (AH salt), equimolar salt of hexamethylenediamine and sebacic acid (SH salt), and ω-laurolactam each had a weight of 50/20/0/30 A total of 20 kg was weighed so as to obtain a ratio and placed in a batch type polymerization can having an internal volume of 80 L equipped with a stirrer having a double helical ribbon blade and a heating medium jacket. After sufficiently substituting the inside of the polymerization can with nitrogen, heating was started at 290 ° C. while stirring at 30 rpm. When the can internal pressure reached 1.7 MPa (gauge pressure), the heating temperature was changed to 270 ° C. to maintain the can internal pressure. The pressure was gradually released to atmospheric pressure over 90 minutes from the time when the internal temperature reached 220 ° C. When the atmospheric pressure was reached, nitrogen gas was circulated at 5 L / min and the inside of the can was blown for 30 minutes. Thereafter, nitrogen pressure of 0.4 MPa (gauge pressure) was applied into the can, and the polymer discharged into the water bath was pelletized with a strand cutter.

The obtained pellets were allowed to stand at room temperature for 24 hours, and then charged into a batch type extraction vessel filled with 35 ° C. ion-exchanged water (extracted water) 20 times the pellet weight. The amount of air contained in the extracted water was 15 mL dissolved in 1 L of extracted water. Thereafter, the extracted water was heated to 60 ± 1 ° C. and extracted for 48 hours. The upper part of the extraction water surface was agitated with a stirrer, and the pellet which floats was settled. The treated pellets were thoroughly rinsed with room temperature ion exchange water and dehydrated with a dehydrator. Table 1 shows the measurement results of the relative viscosity, the melting peak temperature after extraction of the low polymer content (Tm), and the pellet color tone YI of the obtained pellets.

(Example 2)
The ratios of ε-caprolactam, hexamethylenediamine and adipic acid equimolar salt (AH salt), hexamethylenediamine and sebacic acid equimolar salt (SH salt), and ω-laurolactam were respectively 35/15/35/15. The same as Example 1 except for the weight ratio.

(Example 3)
The ratios of ε-caprolactam, equimolar salt of hexamethylenediamine and adipic acid (AH salt), equimolar salt of hexamethylenediamine and sebacic acid (SH salt) and ω-laurolactam were respectively 30/10/20/40. And the same as Example 1 except that the temperature of the extracted water was 40 ± 1 ° C.

Example 4
The ion exchange water used for extraction water was boiled, and the amount of air dissolved in 1 L of extraction water was reduced to 5 mL. Others were the same as in Example 2.

(Example 5)
During the extraction of pellets, the same procedure as in Example 4 was performed, except that the upper part of the extracted water surface was not stirred. During the extraction, no levitation of the pellet was observed.

(Example 6)
Example 2 was the same as Example 2 except that the extraction time was 24 hours.

(Example 7)
Example 2 was the same as Example 2 except that the extraction time was 72 hours.

(Example 8)
Example 2 was the same as Example 2 except that the maximum temperature of the extracted water was 40 ± 1 ° C. and the extraction time was 72 hours.

(Comparative Example 1)
During the extraction of the pellets, it was the same as Example 1 except that the upper part of the extracted water surface was not stirred. During extraction, the pellets floated on the water surface and contact with air was observed.

(Comparative Example 2)
The ratios of ε-caprolactam, hexamethylenediamine and adipic acid equimolar salt (AH salt), hexamethylenediamine and sebacic acid equimolar salt (SH salt), and ω-laurolactam were respectively 35/15/35/15. The same as Comparative Example 1 except that the weight ratio of

(Comparative Example 3)
The ratios of ε-caprolactam, equimolar salt of hexamethylenediamine and adipic acid (AH salt), equimolar salt of hexamethylenediamine and sebacic acid (SH salt) and ω-laurolactam were respectively 30/10/20/40. Comparative Example 1 except that the weight ratio of the extracted water was 40 ± 1 ° C.

(Comparative Example 4)
Example except that the amount of air contained by boiling the ion-exchanged water used for the extraction water is reduced to 5 mL and the maximum temperature of the extraction water is 80 ± 1 ° C. The conditions were the same as 2. After extraction for 48 hours, the state of the pellet was confirmed, and fusion was observed.

(Comparative Example 5)
The same as Comparative Example 2 except that the extraction time was 24 hours.

(Comparative Example 6)
It was the same as Comparative Example 2 except that the maximum temperature of the extracted water was 40 ± 1 ° C. and the extraction time was 72 hours.

Claims (5)

  A copolymerized polyamide having a melting peak temperature (Tm) measured in accordance with JIS K 7121 of 130 ° C. or less, obtained by copolymerizing two or more monomers, and the yellowing degree YI of the polyamide pellet is −2.0 or less. Copolyamide pellets characterized in that the low polymerization component soluble in hot water at 60 ° C. is 2.0% by weight or less.   The copolymerized polyamide pellet according to claim 1, wherein the monomer to be copolymerized is an aliphatic monomer.   The two or more types of monomers are at least two types selected from a monomer constituting polycaproamide, a monomer constituting polyhexamethylene adipamide, and a monomer constituting polydodecanamide, Item 3. The copolymerized polyamide pellet according to item 1 or 2.   Soluble in 60 ° C hot water in the polyamide after polymerization when producing a copolymerized polyamide having a melting peak temperature (Tm) measured in accordance with JIS K 7121 of 130 ° C or lower, obtained by copolymerizing two or more types of monomers. In the process of reducing the low polymer by hot water extraction, the maximum temperature of the hot water to be treated is (Tm-40 ° C.) or less, and the amount of dissolved air is 15 mL or less with respect to 1 L of hot water to be treated. The method for producing a copolymerized polyamide pellet according to any one of claims 1 to 3, wherein:   Soluble in 60 ° C hot water in the polyamide after polymerization when producing a copolymerized polyamide having a melting peak temperature (Tm) measured in accordance with JIS K 7121 of 130 ° C or lower, obtained by copolymerizing two or more types of monomers. In the step of reducing the low polymer by hot water extraction, the maximum temperature of the hot water to be treated is (Tm−40 ° C.) or less, and pellets floating on the hot water surface are precipitated in water. The manufacturing method of the copolyamide pellet of any one of Claims 1-3.