JP5042541B2 - Method for producing polyamide resin composition, and polyamide resin composition - Google Patents

Description

  The present invention relates to a polyamide resin capable of solving the problem of metal precipitation during molding and providing a polyamide molded article having excellent heat aging resistance.

  When subjected to various thermal histories, the polyamide resin undergoes thermal degradation and oxidative degradation, increasing yellowness, changing molecular weight, and lowering mechanical properties such as toughness and durability. Various heat histories include polymerization, melt kneading, molding (injection, extrusion, blow, spinning, film, etc.) or use in a high temperature environment.

  In order to reduce the degree of deterioration in the thermal history, a method of adding a phosphorus compound such as sodium hypophosphite that acts as a heat stabilizer to a polyamide resin is well known and is a well-used method. .

  On the other hand, in order to improve heat aging resistance, a method of adding a copper compound such as copper iodide and potassium iodide and a halogen compound to a polyamide as a heat stabilizer in a long-term high-temperature environment is also well known. This is the method used.

  Japanese Patent Application Laid-Open No. 8-333511 (Patent Document 1) discloses a technique in which the above heat stabilizer is combined, that is, hypophosphorous acid or alkali metal or alkaline earth metal salt of this acid, copper halide and halogen compound. A polyamide excellent in weather resistance to which a ternary stabilizer is added is disclosed. In Patent Document 1, as for the method of adding the ternary stabilizer, for example, it can be added to the monomer before or during the polymerization, it can be mixed into the polymer melt using an extruder, etc. It is mentioned that it can be applied to the surface of a solid polymer or the surface of a solid molding composition, preferably introduced into the polymer melt using an extruder.

However, when the present inventors added a reducing phosphorus compound such as sodium hypophosphite, a copper compound, and a halogen compound to the polyamide in combination, an oxidation-reduction reaction in which the copper compound becomes metallic copper is likely to occur. There was also a phenomenon in which metallic copper was deposited in the piping of the extruder or molding machine, in the apparatus, on the screw surface or on the cylinder surface. Further, it has been found that the deposited metal copper is mixed in the polyamide resin or the molded product thereof, and problems such as the heat aging property being not sufficiently improved are generated.
JP-A-8-333511

  Therefore, the present invention is a method for producing a polyamide resin composition in which a ternary heat stabilizer of a phosphorus compound, a copper compound and a halogen compound is added to polyamide, and the metal copper hardly precipitates even in an extruder or a molding machine. It aims at providing the manufacturing method which can obtain the polyamide resin composition in which aging property was improved.

  As a result of intensive investigations to solve the above problems, the present inventors have added a reducing phosphorus compound in the polyamide resin polymerization step, thereby reducing the reducing phosphorus element remaining in the polyamide resin to a specific amount. The polyamide resin composition obtained by adding a specific amount of a copper compound and a halogen compound (excluding copper halide) to the polyamide resin thus obtained is less susceptible to precipitation of metal copper and has a heat aging resistance. Also found it to be excellent.

That is, the present invention
[1] A method for producing a polyamide resin composition, comprising at least one reducing phosphorus compound added to obtain a polyamide resin, a polyamide polymerization step, a copper compound and a halogen compound (provided that the copper halide is added) A polyamide resin composition production process for obtaining a polyamide resin composition by adding
[2] In the polyamide polymerization step, when the amount of reducing phosphorus element remaining in the polyamide resin is X mol per 10 ⁶ g of polyamide in the polyamide resin, X satisfies the following formula (I): Reducing the amount of reducing phosphorus element, the production method according to the above [1],
0 ≦ X ≦ 0.3 (I);
[3] In the polyamide polymerization step, when the amount of copper element added to the polyamide resin is Y mol per 10 ⁶ g of polyamide in the polyamide resin, Y satisfies the following formula (II): [1] Or the production method according to [2],
0.3 ≦ Y ≦ 5 (II);
[4] The reducing phosphorus compound is at least one selected from the group consisting of phosphorous acid, hypophosphorous acid, metal phosphite, metal hypophosphite, and phosphite.
The production method according to any one of [1] to [3] above;
[5] The production method according to any one of [1] to [4], wherein in the polyamide resin composition production step, the copper compound and the halogen compound are added to the polyamide resin by a melt kneading method;
[6] In the polyamide resin composition manufacturing process, the copper compound and the halogen compound are added to the polyamide resin so that the molar ratio of halogen element to copper element (halogen / copper) is 3 to 30; The method for producing a polyamide resin composition according to any one of [1] to [5] above;
[7] A polyamide resin composition produced by the production method according to any one of [1] to [6].

  According to the production method of the present invention, it is possible to provide a polyamide resin composition having excellent long-term heat aging resistance and less precipitation of metallic copper in an extruder or molding machine.

  Hereinafter, the contents of the present invention will be described in detail.

  As described above, the method for producing a polyamide resin composition according to the present invention includes a polyamide polymerization step of obtaining a polyamide resin by adding at least one reducing phosphorus compound to a polyamide raw material, a copper compound and a halogen in the polyamide resin. And a step of adding a compound (excluding copper halide) to obtain a polyamide resin composition. Therefore, first, substances used in each process and substances manufactured in each process will be described below.

  First, polyamide will be described.

  The polyamide resin used in the present invention is not particularly limited as long as it is a polymer having an amide bond (—NHCO—) in the main chain. For example, polycaprolactam (nylon 6), polytetramethylene adipamide (nylon 46), Polyhexamethylene adipamide (nylon 66), polyhexamethylene sebamide (nylon 610), polyhexamethylene dodecamide (nylon 612), polyundecamethylene adipamide (nylon 116), polyundecalactam (nylon) 11), polydodecalactam (nylon 12), polytrimethylhexamethylene terephthalamide (nylon TMHT), polyhexamethylene isophthalamide (nylon 6I), polynonanemethylene terephthalamide (9T), polyhexamethylene terephthalamide (6T), Libis (4-aminocyclohexyl) methane dodecamide (nylon PACM12), polybis (3-methyl-aminocyclohexyl) methane dodecamide (nylon dimethyl PACM12), polymetaxylylene adipamide (nylon MXD6), polyundecamethylenehexahydro And terephthalamide (nylon 11T (H)). Moreover, the polyamide copolymer containing 2 or more types of different polyamide components among these, a mixture, etc. may be sufficient. The presence or absence of an amide bond can be confirmed by an infrared absorption spectrum (IR).

  The polyamide raw material used in the present invention is not particularly limited as long as it is a well-known raw material used for producing a polymer having an amide bond (-NHCO-) in the main chain. And a lactam or a salt or mixture of a polymerizable diamine and a dicarboxylic acid, and a polymerizable oligomer. These raw materials may be used as the raw material itself or as an aqueous solution.

  From the viewpoint of achieving the object of the present invention, the molecular weight of the polyamide is such that the relative viscosity at 25 ° C. is preferably 2.0 to 6.5, more preferably 2.0% to 6.5%, more preferably 98% sulfuric acid concentration in accordance with JIS-K6810. It is 2.3 to 5.5, more preferably 2.5 to 5.5. By setting it within this range, it becomes possible to obtain a molded product stably in various moldings.

  The carboxyl group concentration ratio of the polyamide used in the present invention is preferably 0.40 to 0.85, more preferably 0.50 to 0.80, and still more preferably 0.55 to 0.75. .

The carboxyl group concentration ratio means a value calculated by {[COOH] / ([COOH] + [NH ₂ ])} where the carboxyl group concentration and amino group concentration in the polyamide are [COOH] and [NH ₂ ], respectively. . By making the carboxyl group concentration ratio within this range, copper precipitation and metal corrosion can be suppressed, and heat aging resistance can be improved.

  The carboxyl group concentration ratio can be adjusted by adding a terminal adjusting agent to the polyamide raw material.

  The terminal modifier is not particularly limited as long as it is a compound containing a carboxylic acid in the molecular structure, but dicarboxylic acids and monocarboxylic acids are preferably used. Examples of the dicarboxylic acid include malonic acid, dimethylmalonic acid, succinic acid, glutaric acid, adipic acid, 2-methyladipic acid, trimethyladipic acid, pimelic acid, 2,2-dimethylglutaric acid, and 3,3-diethylsuccinic acid. , Azelaic acid, sebacic acid, suberic acid, dodecanedioic acid, eicodioic acid, terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, 2-chloroterephthalic acid, 2-methylterephthalic acid, 5-methylisophthalic acid, 5-sodium sulfoisophthalic acid Examples include acid, hexahydroterephthalic acid, hexahydroterephthalic acid, and diglycolic acid. The monocarboxylic acid is an aliphatic monocarboxylic acid such as acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, lauric acid, tridecylic acid, myristic acid, palmitic acid, stearic acid, pivalic acid, isobutyric acid, And alicyclic monocarboxylic acids such as cyclohexanecarboxylic acid, benzoic acid, toluic acid, α-naphthalenecarboxylic acid, β-naphthalenecarboxylic acid, methylnaphthalenecarboxylic acid, and phenylmonoacetic acid. . These carboxylic acid compounds may be used alone or in combination of two or more.

  As a method for producing the polyamide resin, a known method can be used. For example, a ring-opening polycondensation method using a lactam such as ε-caprolactam as a polyamide raw material, a heat melting method using a diamine / dicarboxylate such as hexamethylene adipamide or a mixture thereof as a raw material can be used. Further, a solid salt of a polyamide raw material or a solid phase polymerization method performed at a temperature below the melting point of the polyamide, a solution method using a dicarboxylic acid halide component and a diamine component, or the like can also be used. These methods may be combined as necessary. Among them, the most efficient method is a heat melting method or a method combining a heat melting method and solid phase polymerization.

  The polymerization form may be a batch type or a continuous type. The polymerization apparatus is not particularly limited, and a known apparatus such as an autoclave type reactor, a tumbler type reactor, an extruder type reactor such as a kneader, or the like can be used.

  Next, the reducing phosphorus compound will be described.

  The reducing phosphorus compound used in the present invention includes (1) phosphorous acid and hypophosphorous acid, (2) phosphorous acid metal salt and hypophosphorous acid metal salt, and (3) phosphorous acid ester. It can be selected from phosphorous acid compounds and hypophosphorous acid compounds.

  Examples of (1) phosphorous acid and hypophosphorous acid include phosphorous acid, hypophosphorous acid, pyrophosphorous acid, and diphosphorous acid. (2) The metal phosphite and hypophosphite metal salts of (2) are the above (1) phosphorous acids and hypophosphorous acids and groups 1 and 2 of the periodic table, manganese, zinc, aluminum, Examples include salts with ammonia, alkylamines, cycloalkylamines, and diamines. The phosphites of (3) are represented by the following general formula.

Phosphite; (OR) _n P (OH) _3-n
Here, n represents 1, 2 or 3, and R represents an alkyl group, a phenyl group, or a substituted alkyl group in which a part of these groups is substituted with a hydrocarbon group or the like. When n is 2 or more, a plurality of (RO) groups in the general formula may be the same or different. Examples of R include methyl, ethyl, n-propyl, n-butyl, t-butyl, n-hexyl, cyclohexyl, n-octyl, nonyl, decyl, stearyl and oleyl. An aliphatic group such as a group, an aromatic group such as a phenyl group or a biphenyl group, or an aromatic group having a substituent such as a hydroxyl group, a methyl group, an ethyl group, a propyl group, a methoxy group, or an ethoxy group.

The addition amount of the reducing phosphorus compound to 10 ⁶ g of the polyamide raw material is preferably 0.01 to 5 mol, more preferably 0.03 to 4 mol, and most preferably 0.05 to 3 mol in terms of phosphorus element. By making it in this range, improvement in heat aging resistance is achieved.

  Next, a copper compound and a halogen compound will be described.

  As the copper compound used in the present invention, copper halide, copper acetate, copper propionate, copper benzoate, copper adipate, copper terephthalate, copper isophthalate, copper salicylate, copper nicotinate, copper stearate, etc. Examples thereof include copper complex salts coordinated to a chelating agent such as ethylenediamine (en) and ethylenediaminetetraacetic acid. These copper compounds may be used independently and may mix 2 or more types. Among these, preferred are copper iodide, cuprous bromide, cupric bromide, cuprous chloride, and copper acetate.

  Examples of the halogen compound (excluding copper halide) used in the present invention include sodium iodide, potassium iodide, iodine, sodium bromine, potassium bromine, sodium chloride, and potassium chloride. Of these, potassium iodide is most preferably used.

  The addition amount of the halogen compound is preferably 3 to 30, more preferably 5 to 25, and most preferably 5 to 22 in terms of the molar ratio of halogen element to copper element (halogen / Cu) in the polyamide. . By making it into this range, suppression of copper precipitation and improvement of heat aging resistance are achieved.

  In the method for producing a polyamide resin composition according to the present invention, first, at least one reducing phosphorus compound is added in the polyamide polymerization step using the materials described above.

  Here, the polyamide polymerization step in the present invention refers to a step of producing a prepolymer having a degree of polymerization of about 10 from a polyamide raw material. In the present invention, the method of adding a reducible phosphorus compound to the polyamide raw material is most preferable from the viewpoint that suppression of copper precipitation and improvement in heat aging properties are easily achieved, but the reduction is performed at any stage within the polyamide polymerization process. A phosphorous compound may be added.

In the subsequent polymerization process and melt-kneading process, some of the reducing phosphorus compound added in the polyamide polymerization process remains as a hypophosphorous acid or phosphite compound having reducibility, while others are phosphorous compounds. Oxidized to non-reducing phosphorus compounds such as acids, metal salts or ester compounds. The reducible phosphorus element remaining in the polyamide resin means the remaining phosphorous acid compound and the phosphorus element of the phosphorous acid compound. The concentration of the phosphorus element in the reducing and non-reducing phosphorus compounds in the polyamide resin can be measured using, for example, capillary electrophoresis. More specifically, first, a calibration curve is created by measuring a hypophosphite ion standard solution, a phosphite ion standard solution, and a phosphate ion standard solution with known concentrations using capillary electrophoresis. Next, the polyamide resin is suspended in water, sonicated at room temperature, filtered, and measured by capillary electrophoresis using the residual liquid. From the calibration curve, hypophosphite ions The phosphite ion and phosphate ion concentration can be determined. By converting the obtained hypophosphite ion and phosphite ion concentration into the molar amount of phosphorus element with respect to 10 ⁶ g of polyamide, the concentration of reducing phosphorus element remaining in the polyamide resin can be obtained.

When the amount of the reducing phosphorus element remaining in the polyamide resin is X mole per 10 ⁶ g of polyamide, the range is 0 ≦ X ≦ 0.3, preferably 0 ≦ X ≦ 0.27, and 0 ≦ X. The range of ≦ 0.25 is most preferred. Here, the polyamide 10 ⁶ g means a polyamide component 10 ⁶ g in the polyamide resin. By making it into this range, suppression of copper precipitation and improvement of heat aging resistance are easily achieved.

  In the method for producing a polyamide resin composition according to the present invention, a copper compound and a halogen compound (however, excluding copper halide) are added to the polyamide resin.

  The addition of the copper compound and the halogen compound may be carried out in any of powder, granule, aqueous solution, and master batch. Also, it may be added by blending and coating on the polyamide surface, or it may be added by melting and kneading. However, from the viewpoint that suppression of copper precipitation and improvement of heat aging resistance are easy to achieve. A method of kneading is preferable, and a method of melt-kneading a copper batch and a halogen compound as a master batch is particularly preferable.

  The melt-kneading can be carried out by applying a kneader generally put into practical use. For example, a single-screw or multi-screw kneading extruder, a roll, or a Banbury mixer may be used.

Assuming that the amount of copper element added to the polyamide resin is Y mole per 10 ⁶ g of polyamide in the polyamide resin, the range is 0.3 ≦ Y ≦ 5, preferably 0.5 ≦ Y ≦ 4.5. .5 ≦ Y ≦ 4 is most preferable. By making it into this range, suppression of copper precipitation and improvement of heat aging resistance are achieved.

  The relationship between the molar amount X of the reducing phosphorus element remaining in the polyamide resin and the addition amount Y of the copper compound is preferably in the range of 0.25 ≦ (Y−X) ≦ 2.0, and 0.50 ≦ The range of (Y−X) ≦ 1.5 is more preferable. By making it into this range, suppression of copper precipitation and improvement of heat aging resistance are easily achieved.

  When the polyamide resin composition of the present invention is molded into various parts, it is preferably 0.005 to 0.5 parts by mass, more preferably 0.05 to 0.00 parts per 100 parts by mass of the polyamide resin composition of the present invention. By adding 5 parts by mass of a higher fatty acid compound, it is possible to improve moldability such as fluidity, plasticization, releasability and the like, and more prominently improve the heat aging resistance, which is the subject of the present invention, and suppress copper precipitation. It is possible to

  The higher fatty acid compound is at least one compound selected from higher fatty acids, higher fatty acid metal salts, higher fatty acid amides and higher fatty acid esters. Among them, preferred higher fatty acid compounds are higher fatty acid stearic acid and erucic acid, higher fatty acid metal salt is calcium stearate, aluminum stearate, calcium montanate, sodium montanate, higher fatty acid amide is erucic acid amide, oleic acid amide, Ethylene bisstearyl amide, N-stearyl erucamide, N-stearyl stearyl amide and higher fatty acid esters can be exemplified by stearyl stearate. Among these, it is preferable to use higher fatty acid amides such as erucic acid amide, oleic acid amide, ethylene bisstearyl amide, N-stearyl erucamide, and N-stearyl stearyl amide.

  The polyamide resin composition has additives that are conventionally used for polyamides, such as pigments, dyes, moldability improvers, organic antioxidants, ultraviolet absorbers, lubricants, plastics, to the extent that the object of the present invention is not impaired. Agents, flame retardants, fluorescent bleaches, nucleating agents, rubbers and reinforcing materials can also be added.

  The polyamide resin composition thus obtained can be molded into a molded product by a known molding method. Examples of the molding method include press molding, injection molding, gas assist injection molding, welding molding, extrusion molding, blow molding, film molding, hollow molding, multilayer molding, melt spinning, and the like. The obtained molded product is useful in many molding applications (automobile parts, industrial application parts, electrical and electronic parts, gears, etc.) and extrusion applications (tubes, bars, filaments, films, blows, etc.).

EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not restrict | limited to a following example, unless the summary is exceeded. The physical property evaluation described in the following examples and comparative examples was performed as follows.
(1) Relative viscosity of polyamide It implemented according to JIS-K6810. Specifically, a 1% concentration solution ((polyamide resin 1 g) / (98% sulfuric acid 100 ml)) was prepared using 98% sulfuric acid and measured under a temperature condition of 25 ° C.
(2) Carboxyl group concentration ratio of polyamide The carboxyl group concentration was measured by dissolving pellets or pulverized molded articles in benzyl alcohol. More specifically, 50 ml of benzyl alcohol is added to about 4.0 g of a sample, heated to 170 ° C., and phenolphthalein is added. After dissolving, titrate with 0.1 N NaOH aqueous solution to determine the carboxyl group concentration.

Carboxyl group concentration [COOH] = (f × 0.1 × A / S) × 100f
However, f = factor of 0.1 N NaOH aqueous solution A = consumption amount of 0.1 N NaOH aqueous solution (ml)
S = Sample mass (g)
On the other hand, the amino group concentration was measured by dissolving pellets or pulverized molded articles in a phenol aqueous solution. More specifically, after dissolving about 3.0 of the sample in 100 ml of 90% aqueous phenol, 1 / 40N hydrochloric acid is added dropwise to neutralize and the amount of hydrochloric acid required up to the neutralization point is determined. The same measurement is performed without adding a sample, and a blank is obtained.

Amino group concentration [NH ₂ ] = {F × (1/40) × (A−B) / S} × 1000F
However, f = 1 / 40N hydrochloric acid factor A
A = consumption of 1 / 40N hydrochloric acid [ml]
B: Consumption of 1 / 40N hydrochloric acid (when blank) [ml]
S: Sample mass [g]
Using [COOH] and [NH ₂ ] measured in this manner, the carboxyl group concentration ratio (%) = [COOH] / ([COOH] + [NH ₂ ])} was calculated.
(3) Phosphorus element concentration and reducing phosphorus element concentration in polyamide (3-1) Phosphorus element concentration: 0.5 g of a sample was weighed, 20 ml of concentrated sulfuric acid was added, and wet decomposition was performed on a heater. After cooling, 5 ml of hydrogen peroxide was added, heated on a heater, and concentrated until the total amount became 2-3 ml. The mixture was cooled again to 500 ml with pure water. The apparatus was quantified at a wavelength of 213.618 (nm) by high frequency inductively coupled plasma (ICP) emission analysis using IRIS / IP manufactured by Thermo Jarrel Ash. The concentration of phosphorus element was expressed as the concentration CP (mol) of phosphorus element with respect to 10 ⁶ g of polyamide using this quantitative value.

  (3-2) Phosphorus element concentration: 100 cc of water was added to 50 g of the sample, and after ultrasonic treatment at room temperature for 15 minutes, the filtrate was obtained, and then a capillary electrophoresis apparatus HP3D manufactured by Hewlett Packard was used. The concentration (molar) ratio of hypophosphite ion, phosphite ion and phosphate ion was measured. The concentration ratio was calculated by preparing a calibration curve by measuring hypophosphite ion standard solution, phosphite ion standard solution, and phosphate ion standard solution with known concentrations in the same manner.

The concentration X of the reducing phosphorus element was determined by converting to the molar amount of phosphorus with respect to 10 ⁶ g of polyamide using the following formula.

Reducing phosphorus element concentration X = CP × (CP ₁ + CP ₂ ) / (CP ₁ + CP ₂ + CP ₃ )
CP: Concentration (mol) of phosphorus element with respect to 10 ⁶ g of polyamide determined in (3-1)
CP ₁ : Concentration (molar) ratio of hypophosphite ion obtained in (3-2) CP ₂ : Concentration (molar) ratio of phosphorous acid ion obtained in (3-2) CP ₃ : (3-2 ) Phosphate ion concentration (molar) ratio determined in (4) (4) Halogen element in copper, copper element concentration and molar ratio of halogen element to copper element (halogen / Cu)
Taking the iodine as an example, the halogen element concentration (Z) in the halogen compound is combusted in a flask in which the sample is replaced with high-purity oxygen, and the generated gas is collected in an absorbing solution. Iodine was quantified using a potentiometric titration method with a 1 / 100N silver nitrate solution, and converted to a molar amount based on 10 ⁶ g of polyamide.

The copper element concentration (Y) was determined by adding sulfuric acid to the sample, dropping nitric acid while heating, decomposing the organic component, measuring the decomposition solution with pure water, and then using an ICP emission analysis (high frequency plasma emission analysis) method. It quantified and converted into the molar amount with respect to 10 ⁶ g of polyamides. As an ICP emission analyzer, Vista-Pro manufactured by SEIKO ELECTRONIC INDUSTRY CO., LTD. Was used.

The molar ratio of halogen element to copper element (halogen / Cu) was calculated according to the formula (Y + Z) / Y using the respective molar amounts.
(5) Precipitation of copper during retention of polyamide resin in molding machine The difference in copper concentration between the molded product obtained by standard molding (a) and the molded product obtained by retention molding (b) is defined as copper deposited in the molding machine. The copper precipitation during the stay in the molding machine was evaluated by the formula.

Copper precipitation during retention in molding machine = (copper concentration of standard molded product (a) −copper concentration of retained molded product (b)) × 100 / copper concentration of standard molded product (a) Standard molded product (a) The stay molded product (b) was produced under the following conditions.

  (A) Standard molded product: Nissei Plastic PS-40E was used as the injection molding machine, and ASTM-D638 type was used as the mold. Cylinder temperature was 280 ° C., mold temperature was 80 ° C., plasticizing stroke was 63 mm, screw rotation speed was 200 rpm, injection time was 10 seconds, and cooling time was 15 seconds to obtain an injection molded product. The residence time during plasticization was 1 minute.

(B) Residual molded product: Nissei Plastic PS-40E was used as the injection molding machine, and ASTM-D638 type was used as the mold. Cylinder temperature was 280 ° C., mold temperature was 80 ° C., plasticizing stroke was 63 mm, screw rotation speed was 200 rpm, injection time was 10 seconds, and cooling time was 15 seconds to obtain an injection molded product. The residence time during plasticization was 60 minutes.
(6) Long-term heat aging resistance of polyamide resin molded product The standard molded product (a) of (5) above was treated in a hot air oven at 180 ° C. for a predetermined time, and then the tensile strength was measured according to ASTM-D638. And the tensile strength after the heat treatment with respect to the tensile strength measured before the heat treatment was calculated as the tensile strength retention, and the heat treatment time at which the tensile strength retention was 50% was defined as the half life.
[Example 1]
<Polyamide polymerization process>
Performed by batch polymerization. Sodium hypophosphite was added to a 50 mass% aqueous solution containing a polyamide 66 raw material (an equimolar salt of hexamethylenediamine and adipic acid). This aqueous solution was charged into a concentration tank, mixed under a temperature condition of about 50 ° C., and replaced with nitrogen. The temperature was then raised from about 50 to about 150 ° C. At this time, in order to keep the pressure in the concentration tank at a gauge pressure of about 0.05 to 0.15 MPa, heating was continued while removing water out of the system and the solution was concentrated to about 80%. The concentrated solution was transferred to an autoclave, the temperature was raised from 150 ° C. to about 220 ° C., and the pressure was increased to about 1.77 MPa using a gauge pressure. Thereafter, the temperature was raised from about 220 ° C. to about 260 ° C., and heating was performed while removing water from the system so as to keep the pressure at about 1.77 MPa. Finally, the pressure was slowly reduced to atmospheric pressure while raising the temperature to about 280 ° C. Pressurized with nitrogen to form a strand from the lower nozzle, cooled with water, cut and discharged as a pellet. The obtained pellet was dried in a nitrogen stream at 150 ° C. to obtain a polyamide resin. The phosphorus element contained 2.26 mol with respect to 10 ⁶ g of polyamide 66. Of these, the reducing phosphorus element was 0.23 mol.
<Polyamide resin composition production process>
For the obtained polyamide resin, copper iodide (CuI) as a copper compound and potassium iodide (KI) as a halogen compound were 290 using a twin screw extruder (TEM35 manufactured by Toshiba Machine Co., Ltd.). The mixture was added by a melt kneading method under a temperature condition of ° C. Addition amounts of copper iodide and potassium iodide were 0.787 mol and 3.937 mol, respectively, with respect to 10 ⁶ g of polyamide. The evaluation results are shown in Table 1. The long-term aging property was as long as 700 hours, and the copper precipitation property was as low as 12%, indicating that a good polyamide resin composition can be obtained.
[Example 2]
<Polyamide polymerization process>
Performed by batch polymerization. Sodium hypophosphite was added to a 50 mass% aqueous solution containing a polyamide 66 raw material (an equimolar salt of hexamethylenediamine and adipic acid). Moreover, adipic acid was added as a terminal group regulator. This aqueous solution was charged into a concentration tank, mixed under a temperature condition of about 50 ° C., and replaced with nitrogen. The temperature was then raised from about 50 to about 150 ° C. At this time, in order to keep the pressure in the concentration tank at a gauge pressure of about 0.05 to 0.15 MPa, heating was continued while removing water out of the system and the solution was concentrated to about 80%. The concentrated solution was transferred to an autoclave, the temperature was raised from 150 ° C. to about 220 ° C., and the pressure was increased to about 1.77 MPa using a gauge pressure. Thereafter, the temperature was raised from about 220 ° C. to about 260 ° C., and heating was performed while removing water from the system so as to keep the pressure at about 1.77 MPa. Finally, the pressure was slowly reduced to atmospheric pressure while raising the temperature to about 280 ° C. Pressurized with nitrogen to form a strand from the lower nozzle, cooled with water, cut and discharged as a pellet. The obtained pellet was dried in a nitrogen stream at 150 ° C. to obtain a polyamide resin. The phosphorus element contained 2.26 mol with respect to 10 ⁶ g of polyamide 66. Of these, the reducing phosphorus element was 0.20 mol.
<Polyamide resin composition production process>
The resulting polyamide resin is melt kneaded with copper iodide (CuI) and potassium iodide (KI) at a temperature of 290 ° C. using a twin screw extruder (TEM35 manufactured by Toshiba Machine Co., Ltd.). Added by the method. Addition amounts of copper iodide and potassium iodide were 0.787 mol and 3.937 mol, respectively, with respect to 10 ⁶ g of polyamide. The evaluation results are shown in Table 1. The long-term aging property was as long as 625 hours, and the copper precipitation property was as low as 10%, indicating that a good polyamide resin composition can be obtained.
[Example 3]
<Polyamide polymerization process>
This was carried out by a continuous polymerization method. Sodium hypophosphite was added to a 50 mass% aqueous solution containing polyamide 66 raw material. This aqueous solution was poured into the concentration layer / reactor at a rate of about 3000 Kg / hr and concentrated to about 90%. Subsequently, it discharged to the flasher and the pressure was slowly reduced to atmospheric pressure. It was transferred to the next container and kept under conditions of a temperature of about 280 ° C. and a pressure below atmospheric pressure. Next, the resin was extruded to form a strand, which was cooled and cut into pellets to obtain a polyamide resin. The phosphorus element contained 1.13 mol with respect to 10 ⁶ g of polyamide 66. Of these, the reducing phosphorus element was 0.03 mol.
<Polyamide resin composition production process>
The resulting polyamide resin is melt kneaded with copper iodide (CuI) and potassium iodide (KI) at a temperature of 290 ° C. using a twin screw extruder (TEM35 manufactured by Toshiba Machine Co., Ltd.). Added by the method. The addition amounts of copper iodide and potassium iodide were 0.53 mol and 9.98 mol, respectively, with respect to 10 ⁶ g of polyamide. The evaluation results are shown in Table 1. The long-term aging property was as long as 625 hours, and the copper precipitation property was as low as 10%, indicating that a good polyamide resin composition can be obtained.
[Example 4]
<Polyamide polymerization process>
This was carried out by a continuous polymerization method. Sodium hypophosphite and sodium aluminate (Na _1.42 Al _0.86 O ₂ ) were added to a 50 mass% aqueous solution containing the polyamide 66 raw material. This aqueous solution was poured into the concentration layer / reactor at a rate of about 3000 Kg / hr and concentrated to about 90%. Subsequently, it discharged to the flasher and the pressure was slowly reduced to atmospheric pressure. It was transferred to the next container and kept under conditions of a temperature of about 280 ° C. and a pressure below atmospheric pressure. Next, the resin was extruded to form a strand, which was cooled and cut into pellets to obtain a polyamide resin. 0.46 mol of phosphorus element was contained with respect to 10 ⁶ g of polyamide 66. Of these, the reducing phosphorus element was 0.00 mol. Moreover, the aluminum element was 0.69 mol.
<Polyamide resin composition production process>
The resulting polyamide resin is melt kneaded with copper iodide (CuI) and potassium iodide (KI) at a temperature of 290 ° C. using a twin screw extruder (TEM35 manufactured by Toshiba Machine Co., Ltd.). Added by the method. The addition amounts of copper iodide and potassium iodide were 0.53 mol and 9.98 mol, respectively, with respect to 10 ⁶ g of polyamide. The evaluation results are shown in Table 2. The long-term aging property was as long as 650 hours, and the copper precipitation property was as low as 8%, indicating that a good polyamide resin composition can be obtained.
[Example 5]
<Polyamide polymerization process>
This was carried out by a continuous polymerization method. Sodium hypophosphite and sodium aluminate (Na _1.42 Al _0.86 O ₂ ) were added to a 50 mass% aqueous solution containing the polyamide 66 raw material. This aqueous solution was poured into the concentration layer / reactor at a rate of about 3000 Kg / hr and concentrated to about 90%. Subsequently, it discharged to the flasher and the pressure was slowly reduced to atmospheric pressure. It was transferred to the next container and kept under conditions of a temperature of about 280 ° C. and a pressure below atmospheric pressure. Next, the resin was extruded to form a strand, which was cooled and cut into pellets to obtain a polyamide resin. 0.46 mol of phosphorus element was contained with respect to 10 ⁶ g of polyamide 66. Of these, the reducing phosphorus element was 0.00 mol. Moreover, the aluminum element was 0.69 mol.
<Polyamide resin composition production process>
With respect to the obtained polyamide resin, copper iodide (CuI), potassium iodide (KI), and ethylenebisstearylamide were mixed at a temperature of 290 ° C. using a twin screw extruder (TEM35 manufactured by Toshiba Machine Co., Ltd.). And added by melt kneading. The addition amounts of copper iodide and potassium iodide were respectively 1.25 mol and 6.25 mol with respect to 10 ⁶ g of polyamide. Further, ethylenebisstearylamide was added so as to be 0.1 part by weight with respect to 100 parts by weight of polyamide. The evaluation results are shown in Table 2. The long-term aging property was as long as 750 hours, and the copper precipitation property was as low as 12%, indicating that a good polyamide resin composition can be obtained.

[Comparative Example 1]
<Polyamide polymerization process>
A polyamide was obtained by carrying out a batch polymerization method in the same manner as in Example 2 except that sodium hypophosphite was not added.
<Polyamide resin composition production process>
Sodium hypophosphite, copper iodide (CuI), and potassium iodide (KI) were added to the obtained polyamide at a temperature condition of 290 ° C. using a twin screw extruder (TEM35 manufactured by Toshiba Machine Co., Ltd.). And added by melt kneading. Sodium hypophosphite, copper iodide and potassium iodide were added in amounts of 2.26 mol, 0.79 mol and 3.94 mol, respectively, with respect to 10 ⁶ g of polyamide.

The evaluation results are shown in Table 2. In this comparative example, the reducing phosphorus compound was not added in the polyamide resin polymerization step, but was added at the time of the melt kneading method using an extruder, so the reducing phosphorus compound was hardly oxidized and remained reducible. It is considered a thing. As a result, the long-term aging property was as short as 500 hours, and the copper precipitation property was as high as 35%, indicating that a high-quality polyamide resin composition could not be obtained.
[Comparative Example 2]
<Polyamide polymerization process>
A polyamide was obtained in the same manner as in Comparative Example 1.
<Polyamide resin composition production process>
Sodium hypophosphite was added to the obtained polyamide and melt-kneaded with a twin screw extruder to obtain a polyamide resin. The phosphorus concentration in this polyamide resin was 2.26 mol of phosphorus element with respect to 10 ⁶ g of polyamide 66. Of these, the reducing phosphorus element was 2.20 mol.

A melt-kneading method of copper iodide (CuI) and potassium iodide (KI) with respect to the obtained polyamide resin at a temperature condition of 290 ° C. using a twin screw extruder (TEM35 manufactured by Toshiba Machine Co., Ltd.). Added at. Addition amounts of copper iodide and potassium iodide were 0.787 mol and 3.937 mol, respectively, with respect to 10 ⁶ g of polyamide.

  The evaluation results are shown in Table 2. Also in this comparative example, the reducing phosphorus compound was not added in the polyamide resin polymerization step, but was added at the time of the melt kneading method by the extruder, so that the reducing phosphorus compound was hardly oxidized and remained reducible. It is thought that. As a result, it was found that the long-term aging property was as short as 500 hours and the copper precipitation property was as high as 30%, so that a high-quality polyamide resin composition could not be obtained.

  As described above, according to the production method of the present invention, it was confirmed that a polyamide resin composition having excellent long-term aging properties and low copper precipitation could be obtained.

  The present invention provides a polyamide resin composition in which the mechanical properties, heat resistance, and chemical resistance of conventional polyamide resins are not impaired, and further improved heat aging resistance and copper deposition are suppressed, and a method for producing the same. Yes, it is suitably used in many molding applications (automobile parts, industrial parts, electrical and electronic parts, gears, etc.) and extrusion applications (tubes, rods, filaments, films, blows, etc.).

Claims (6)

A method for producing a polyamide resin composition, comprising:
A polyamide polymerization step of adding at least one reducing phosphorus compound to obtain a polyamide resin;
The polyamide resin, saw-containing copper compound and a halogen compound (excluding copper halide) and the polyamide resin composition production process to obtain a polyamide resin composition was added and the,
In the polyamide resin polymerization step, when the amount of the reducing phosphorus element remaining in the polyamide resin is X mol per 10 ⁶ g of polyamide in the polyamide resin , reduction is performed so that X satisfies the following formula (I): The manufacturing method which reduces the quantity of a characteristic phosphorus element .
0 ≦ X ≦ 0.3 (I) 2. The production according to claim 1, wherein, in the polyamide polymerization step, Y satisfies the following formula (II) when the amount of copper element added to the polyamide resin is Y mol per 10 ⁶ g of polyamide in the polyamide resin. Method.
0.3 ≦ Y ≦ 5 (II) The reducing phosphorus compound is at least one selected from the group consisting of phosphorous acids, hypophosphorous acids, metal phosphites, metal hypophosphites, and phosphites. Or the manufacturing method of 2 . The manufacturing method according to any one of claims 1 to 3 , wherein, in the polyamide resin composition manufacturing step, the copper compound and the halogen compound are added to the polyamide resin by a melt kneading method. In the said polyamide resin composition manufacturing process, the said copper compound and the said halogen compound are added to the said polyamide resin so that the molar ratio (halogen / copper) of a halogen element and a copper element may be 3-30. 5. The method for producing a polyamide resin composition according to any one of items 1 to 4 . The polyamide resin composition manufactured by the manufacturing method of any one of Claim 1 to 5 .