JP2013100391A - Method for producing polyamide resin composition, and polyamide resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a polyamide resin compositions capable of producing advantageously polyamide resin compositions industrially, with suppressing an excessive increase in viscosity and without using a complex process, even if a fibrous clay mineral is used.SOLUTION: This method for producing polyamide resin compositions includes following processes (i) and (ii) in this order. The process (i) has a process preparing a dispersion in which a monomer constituting a polyamide resin (A) is melted at a temperature higher than the melting point, and while agitating, a fibrous clay mineral (B) and a viscosity modifier (C) are mixed therewith. In the process (i), the mixing proportion (A)/(B) of the polyamide resin (A) to the fibrous clay mineral (B) is 50/50 to 95/5, and the amount of use of the viscosity modifier (C) is 0.5-100 pts.mass relative to 100 pts.mass of the fibrous clay mineral (B). The process (ii) has a process in which the dispersion prepared in the process (i) is polymerized to obtain the resin composition including the polyamide resin (A), the fibrous clay mineral (B) and the viscosity modifier (C).

Description

  The present invention relates to a method for producing a polyamide resin composition, and a polyamide resin composition.

  Conventionally, as a method for reinforcing the mechanical strength of a polyamide resin, it is already widely known that a fiber composition such as glass fiber or carbon fiber or an inorganic filler such as calcium carbonate is blended as a reinforcing material to form a resin composition. ing. A general method of blending these reinforcing materials is a method of mixing and kneading into a polymer using a twin screw extruder or the like.

  However, when fine particles such as clay minerals are used as a reinforcing material, simply mixing and kneading into a polymer does not sufficiently disperse in the polymer, resulting in a resin composition having satisfactory characteristics. There is a problem that can not be. In addition, considering that the monomer constituting the polyamide resin is a starting material for obtaining a reinforced polyamide resin composition, in the general compounding method as described above, the monomer is polymerized to obtain a polymer. A two-stage process is required, that is, a process and a process of mixing a polymer obtained by polymerization and a reinforcing material. Therefore, there was a problem that it was industrially disadvantageous from the viewpoint of simplifying the manufacturing process.

  As an attempt to solve the above problems, a method for obtaining a polyamide resin composition by polymerizing a layered silicate clay mineral represented by montmorillonite or mica in a monomer constituting a polyamide resin has been proposed. ing. According to such a method, it is possible to obtain a resin composition in which the polyamide resin and the layered silicate clay mineral are finely and uniformly dispersed by allowing the polyamide chain to penetrate between the layers of the layered silicate clay mineral. .

  For example, Patent Document 1 and Patent Document 2 describe a resin composition containing a polyamide resin and a layered silicate clay mineral such as montmorillonite, and a method for producing the resin composition. Patent Document 3 and Patent Document 4 describe a resin composition containing a polyamide resin and a fluorinated mica-based mineral that is a layered silicate clay mineral, and a method for producing the resin composition.

  However, the layered silicate clay minerals described in Patent Documents 1 to 4 are liable to cause cleavage (cracking along a specific direction of crystals generated due to a small bonding force). Therefore, in patent documents 1-4, even if the addition amount of a layered silicate clay mineral is small, the melt viscosity of the polyamide resin composition obtained will increase notably. As a result, it is difficult to dispense the polyamide resin composition from the reaction vessel after the polymerization is completed. Therefore, in order to recover the polyamide resin composition from the reaction vessel in a high yield, there is a problem that only a few mass% of the layered silicate clay mineral can be blended in the polyamide resin composition.

  On the other hand, Patent Document 5 describes a method of obtaining a polyamide resin composition by melt-kneading a layered silicate clay mineral subjected to an organic treatment in a polyamide resin. The polyamide resin composition obtained in Patent Document 5 can contain a layered silicate clay mineral at a high concentration. However, in the case of Patent Document 5, the melt viscosity of the obtained resin composition still remained high. In addition, a two-stage process is required, that is, a process of polymerizing a polyamide monomer to obtain a polyamide resin, and a process of mixing the polyamide resin obtained by polymerization and a layered silicate clay mineral. Therefore, there was a problem that it was industrially disadvantageous from the viewpoint of simplifying the manufacturing process.

  In order to solve such problems, a polyamide resin composition using a non-layered clay mineral (for example, a fibrous clay mineral) has been studied. If a clay mineral that is not layered is added during the polymerization of the polyamide resin, an excessive increase in melt viscosity is suppressed, so that the clay mineral can be contained in a high concentration in the resulting resin composition.

  As an example of a method for producing a resin composition containing a polyamide resin and a fibrous clay mineral, from the viewpoint of simplifying the production process, there is a method in which a fibrous clay mineral is previously dispersed in a monomer solution and the dispersion is polymerized. Can be mentioned. However, in this method, when the blending amount of the fibrous clay mineral is a certain ratio or more, the solution viscosity rapidly increases, and there is a problem that the process cannot be transferred to the next step and the operability is inferior.

  As a method for improving the operability when blending such a fibrous clay mineral, for example, Patent Document 6 discloses that when a polyamide resin and a fibrous clay mineral are blended, an organic carboxylate and / or an organic sulfone is used. A method of blending an acid salt is described. However, Patent Document 6 also has a problem in that the increase in the viscosity of the resin composition caused by the fibrous clay mineral cannot be sufficiently suppressed, so that the blending amount of the fibrous clay mineral cannot be increased.

JP-A-62-74957 Japanese Patent No. 2747019 Japanese Patent No. 2941159 Japanese Patent No. 3409921 International Publication No. 2006/006716 Pamphlet JP-A-8-3363

  Accordingly, an object of the present invention is to provide a polyamide that can suppress an excessive increase in viscosity and can advantageously produce a polyamide resin composition industrially without going through complicated steps even when a fibrous clay mineral is used. It aims at providing the manufacturing method of a resin composition.

As a result of intensive studies to solve the above-mentioned problems, the present inventors have reached the present invention.
That is, the present invention has the following contents.
(1) A method for producing a polyamide resin composition, comprising the following steps (i) and (ii) in this order:
Step (i): The monomer constituting the polyamide resin (A) is heated and melted at a temperature equal to or higher than its melting point, and dispersed by blending the fibrous clay mineral (B) and the viscosity modifier (C) while stirring. The step of obtaining a liquid, wherein the blending ratio (A) / (B) of the polyamide resin (A) and the fibrous clay mineral (B) is 50/50 to 95/5, and the viscosity modifier (C) The process whose usage-amount is 0.5-100 mass parts with respect to 100 mass parts of fibrous clay minerals (B).
Step (ii): A step of polymerizing the dispersion obtained in step (i) to obtain a resin composition containing a polyamide resin (A), a fibrous clay mineral (B), and a viscosity modifier (C).
(2) The method for producing a polyamide resin composition according to (1), wherein sepiolite and / or palygorskite is used as the fibrous clay mineral (B).
(3) The method for producing a polyamide resin composition according to (1) or (2), wherein an organic carboxylic acid amine salt, a polyether phosphate ester or an amine salt thereof is used as a viscosity modifier.
(4) Any one of (1) to (3), wherein the temperature X at which the thermogravimetric reduction rate of the viscosity modifier (C) used is 5% by mass is less than the polymerization temperature in step (ii) A process for producing a polyamide resin composition.
(5) In the step (i), stirring is performed in an environment of 80 ° C. and 0.3 rpm so that the rotational viscosity of the dispersion measured with a B-type viscometer is 0.01 to 300 Pa · s. (1) The manufacturing method of the polyamide resin composition in any one of (4).
(6) It contains polyamide resin (A), fibrous clay mineral (B), and viscosity modifier (C), the mass ratio of (A) / (B) is 50/50 to 95/5, and the viscosity The polyamide resin composition, wherein the content of the modifier (C) is 0.0001 to 10 parts by mass with respect to 100 parts by mass of the fibrous clay mineral (B).

  According to the method for producing a polyamide resin composition of the present invention, by using an organic carboxylic acid amine salt, a polyamide resin composition is obtained industrially advantageously while suppressing an increase in viscosity due to a fibrous clay mineral. be able to. Furthermore, according to the method for producing a polyamide resin composition of the present invention, a dispersion containing a component as a raw material is obtained, and the dispersion is subjected to polymerization, thereby simplifying the process without going through a complicated process. Can be

Hereinafter, the present invention will be described in detail.
The method for producing a polyamide resin composition of the present invention (hereinafter sometimes simply referred to as “resin composition”) includes the following steps (i) and (ii) in this order.

Step (i): The monomer constituting the polyamide resin (A) is heated and melted at a temperature equal to or higher than its melting point, and dispersed by blending the fibrous clay mineral (B) and the viscosity modifier (C) while stirring. The step of obtaining a liquid, wherein the blending ratio (A) / (B) of the polyamide resin (A) and the fibrous clay mineral (B) is 50/50 to 95/5, and the viscosity modifier (C) The process whose usage-amount is 0.5-100 mass parts with respect to 100 mass parts of fibrous clay minerals (B).

Step (ii): A step of polymerizing the dispersion obtained in step (i) to obtain a resin composition containing a polyamide resin (A), a fibrous clay mineral (B), and a viscosity modifier (C).

  Hereinafter, in the present invention, the polyamide resin (A) is simply referred to as “component (A)”, the fibrous clay mineral (B) is simply referred to as “component (B)”, and the viscosity modifier (C) is simply referred to as “component (A)”. It may be referred to as “component (C)”.

First, step (i) will be described.
Step (i) is a step of obtaining a dispersion by heating and melting the monomer constituting component (A) to form a solution, then adding component (B), component (C) and water and stirring. .

  Component (A) is a polymer having an amide bond in the main chain, the main raw material of which is aminocarboxylic acid, lactam, diamine and dicarboxylic acid, or a pair of salts of diamine and dicarboxylic acid.

  Specific examples of component (A) include polycaproamide (nylon 6), polytetramethylene adipamide (nylon 46), polyhexamethylene adipamide (nylon 66), polycaproamide / polyhexamethylene adipamide Copolymer (nylon 6/66), polyundecamide (nylon 11), polycaproamide / polyundecamide copolymer (nylon 6/11), polydodecamide (nylon 12), polycaproamide / polydodecamide copolymer (nylon 6/12) , Polyhexamethylene sebamide (nylon 610), polyhexamethylene dodecamide (nylon 612), polyundecamethylene adipamide (nylon 116), and mixtures and copolymers thereof.

  Among these, nylon 6 and nylon 66 are particularly preferable from the viewpoint of excellent heat resistance and easy molding.

  Specific examples of the monomer used as the raw material for component (A) include aminocarboxylic acids such as 6-aminocaproic acid, 11-aminoundecanoic acid, and 12-aminododecanoic acid; ε-caprolactam, ω-undecanolactam, and ω-lauro. Examples include lactams such as lactams; diamines such as tetramethylene diamine, hexamethylene diamine, undecamethylene diamine, and dodecamethylene diamine; dicarboxylic acids such as adipic acid, suberic acid, sebacic acid, and dodecanedioic acid. These diamines and dicarboxylic acids can also be used as a pair of salts.

  As a monomer which becomes a raw material of a component (A), (epsilon) -caprolactam, adipic acid, and hexamethylenediamine are preferable.

  As the component (B) in the present invention, it is preferable to use a fibrous hydrous magnesium silicate mineral. Especially, it is preferable to use sepiolite and a palygorskite from the ease of dispersion | distribution to a component (A).

Sepiolite is a natural mineral containing Mg ₈ Si ₁₂ O ₃₀ (OH) ₄ (OH ₂ ) ₄ .8H ₂ O as a main component, and palygorskite is Mg ₅ Si ₈ O ₂₀ (OH) ₂ (OH ₂ ) _4. It is a natural mineral containing 4H ₂ O as a main component. In the palygorskite, magnesium may be replaced with iron or aluminum.

  In step (i), (A) / (B), which is the blending ratio of component (A) and component (B), needs to be 50/50 to 95/5, and 55/45 to 90/10. It is preferable that it is, and it is more preferable that it is 60 / 40-85 / 15. When the blending amount of the component (B) with respect to the total mass of the component (A) and the component (B) is less than 5% by mass, the resulting resin composition is inferior in bending characteristics. On the other hand, when the compounding amount of the component (B) exceeds 50% by mass, the viscosity of the dispersion obtained in the step (i) becomes too large, and it becomes difficult to obtain a polyamide resin composition.

  As the component (C) in the present invention, an organic carboxylic acid amine salt, a polyether phosphate ester or an amine salt thereof can be used. Among them, an organic carboxylic acid amine salt can be preferably used in that the viscosity adjusting effect is high and the component (C) in the step (ii) is easily discharged out of the polymerization system.

  Component (C) in the present invention is used as a viscosity modifier for reducing the viscosity of the dispersion obtained in step (i). Usually, in the resin composition containing the component (B), the components (B) are electrostatically bonded to each other to form a so-called card house structure, so that the viscosity is remarkably increased. However, in the present invention, by using the component (C), it is possible to suppress the expression of the electrical coupling, and as a result, the viscosity due to the component (B) dispersed in the component (A). A remarkable effect of effectively reducing the increase is achieved. In addition, when a viscosity modifier other than component (C) is used, the increase in viscosity in the dispersion becomes significant, and it is difficult to obtain a resin composition in the subsequent step (ii).

  Examples of the organic carboxylic acid that is a lipophilic group in the organic carboxylic acid amine salt include polyol carboxylic acid and polyether carboxylic acid. The amines which are hydrophilic groups in component (C) are methylamine, ethylamine, propylamine, butylamine, pentylamine, hexylamine, heptylamine, octylamine, nonylamine, decylamine, hexadecylamine, undecylamine, dodecyl. Mention may be made of amine, tridecylamine, tetradecylamine, dimethylamine, dipropylamine, dibrylamine, dipentylamine, dihexylamine, diheptylamine, dioctylamine, dinonylamine, didecylamine or mixtures thereof. Among these, polyether carboxylic acid amine salts are particularly preferable in terms of suppressing the increase in viscosity of the dispersion and being excellent in the effect of sufficiently reducing the viscosity of the resulting resin composition.

In the present invention, as the component (C), a temperature at which the thermal weight reduction rate measured in air at a heating rate of 10 ° C./min is 5% by mass (hereinafter sometimes referred to as “temperature X”). It is preferable to use a material having a temperature of 100 to 270 ° C, and it is more preferable to use a material having a temperature of 180 to 250 ° C. Moreover, it is preferable that temperature X is less than the polymerization temperature in the said process (ii).
A method for obtaining the temperature X will be described later in Examples.

  The reason why the temperature X of the component (C) used is preferably in the above range will be described below. If a large amount of the component (C) remains in the polyamide resin composition obtained by polymerization, the polyamide resin composition becomes flexible due to the action of the remaining component (C), so that the bending properties are significantly inferior. It will be a thing. In order to solve such a problem, the component (C) needs to be discharged out of the polymerization system during the polymerization. In the present invention, when the temperature X is 100 to 270 ° C. and the polymerization temperature in the step (ii) is in the range described later, the component (C) is effectively volatilized during the polymerization reaction in the step (ii). Or it is thermally decomposed and can be easily discharged out of the polymerization system. Here, if the temperature X exceeds 270 ° C., it may be difficult to discharge the component (C) out of the polymerization system, and the bending properties of the resulting polyamide resin composition may be inferior. On the other hand, when the temperature X is less than 100 ° C., the component (C) may be decomposed when a dispersion is obtained. Therefore, the component (C) cannot be stably present, and the effect of suppressing the thickening due to the component (B) may be reduced. Further, when the temperature X exceeds the polymerization temperature in the step (ii), the component (C) is not sufficiently discharged out of the polymerization system during the polymerization, and the bending characteristics of the resulting polyamide resin composition are deteriorated. Tend.

  In process (i), the usage-amount of a component (C) needs to be 0.5-100 mass parts with respect to 100 mass parts of components (B), and it is preferable that it is 1-50 mass parts. 5 to 30 parts by mass is more preferable. If the amount of component (C) used is less than 0.5% by mass with respect to 100 parts by mass of component (B), the effect of suppressing thickening due to component (B) dispersed in component (A) is insufficient. It becomes. On the other hand, when it exceeds 100 parts by mass, the resulting polyamide resin composition is inferior in bending properties, and in addition, there is a problem that it is not economical.

  The stirring method in step (i) is not particularly limited as long as each component is uniformly mixed, and examples thereof include a method of melt-mixing while stirring with heating. In that case, the shape and the rotational speed of the stirring blade are not particularly limited.

  In step (i), the rotational viscosity of the dispersion measured with a B-type viscometer in an environment of 80 ° C. and 0.3 rpm is preferably 0.01 to 300 Pa · s, and preferably 1 to 200 Pa · s. It is more preferable that the pressure is 3 to 150 Pa · s. When the rotational viscosity is less than 0.01 Pa · s, the dispersibility of the component (B) is poor, so that the effect of improving the bending properties becomes insufficient. On the other hand, if it exceeds 300 Pa · s, the rotational viscosity of the dispersion is no longer too high, and it may be difficult to dispense the dispersion to the polymerization apparatus in the subsequent step (ii).

  In step (i), the residual ratio of the dispersion, which is an index indicating the liquid feeding property of the dispersion, is preferably 15% or less, and more preferably 10% or less. If the residual ratio of the dispersion exceeds 15%, the liquid feeding property when the dispersion is fed to the step (ii) is deteriorated, leading to a decrease in productivity and the yield may be lowered. In addition, how to obtain | require a dispersion liquid residual rate is mentioned later in an Example.

  In the step (i), the amount of the monomer constituting the component (A), the component (B) and the component (C) is as follows when the final polyamide resin composition of the present invention is obtained. The amount must be within the above range. Moreover, water can be further added as needed. By adding water, dispersion of the component (B) in the component (A) may be promoted. The amount of water added is not particularly limited as long as the monomer constituting component (A), component (B) and component (C) are uniformly mixed.

Next, process (ii) is demonstrated.
Step (ii) is a step of polymerizing the dispersion obtained in step (i) to obtain a resin composition containing component (A), component (B) and component (C).

  In the step (ii), when a conventional layered silicate is used as a reinforcing material, there is a problem that the viscosity of the polymer increases remarkably because dispersion occurs in the polymerization step. Therefore, the addition amount of the reinforcing material cannot be increased, and the reinforcing effect cannot be sufficiently exhibited. Therefore, there is a problem that the bending characteristics of the obtained resin composition are not sufficiently improved.

  However, in the present invention, the fibrous clay mineral (B) is used as the reinforcing material instead of the layered silicate. Therefore, an increase in melt viscosity during the polymerization process can be suppressed, that is, the melt viscosity can be controlled within a preferable range. Therefore, the amount of fibrous clay mineral added to the resin composition can be increased, and the effect of improving the bending characteristics can be sufficiently exhibited. In addition, an increase in the melt viscosity of the dispersion can be suppressed by using the component (C). That is, in the present invention, a polyamide resin composition in which the effect of improving the bending property is sufficiently expressed can be obtained with high productivity by the synergistic effect of the component (B) and the component (C).

The melt viscosity in step (ii) is preferably 250,000 Pa · s or less, more preferably 50000 Pa · s or less at a temperature of 250 ° C. and a shear rate of 10 ⁻³ s ⁻¹ .

  The polymerization temperature in step (ii) is preferably 200 to 300 ° C, and more preferably 230 to 270 ° C. When the polymerization temperature is less than 200 ° C., the component (C) is not easily decomposed, and it may be difficult to discharge it outside the polymerization system. As a result, a polyamide resin composition having a high content of the component (C) can be obtained, which results in poor bending characteristics. There is also a problem that the polymerization reaction itself does not proceed well. On the other hand, when the polymerization temperature exceeds 300 ° C., the decomposition reaction of the polyamide resin is promoted, so that it may be difficult to contain the high molecular weight polyamide resin.

  The polyamide resin composition of the present invention can be obtained by the production method as described above. In this resin composition, since the component (C) is volatilized or decomposed, its content is remarkably reduced as compared with the blended amount. Content of a component (C) needs to be 0.0001-10 mass parts with respect to 100 mass parts of components (B), and it is preferable that it is 0.01-1 mass part.

  The polyamide resin composition produced by the production method of the present invention has a heat stabilizer, an antioxidant, a pigment, an anti-coloring agent, a weathering agent, a flame retardant, at any stage, as long as its properties are not significantly impaired. Plasticizers, crystal nucleating agents, mold release stabilizers, and the like may be added.

  The resin composition obtained by the production method of the present invention can be blended with other polymers as necessary. Examples of such polymers include polybutadiene, butadiene-styrene copolymer, acrylic rubber, ethylene-propylene copolymer, ethylene-propylene-diene copolymer, natural rubber, chlorinated butyl rubber, elastomers such as chlorinated polyethylene, And acid-modified products thereof with maleic anhydride, styrene-maleic anhydride copolymer, styrene-phenylmaleimide copolymer, polyvinyl chloride, polyethylene terephthalate, polybutylene terephthalate, polyacetal, polyvinylidene fluoride, polysulfone, polyphenylene sulfide , Polyethersulfone, phenoxy resin, polyphenylene ether, polymethyl methacrylate, polyether ketone, polyarylate, polycarbonate, polytetrafluoroethylene, etc. It is below.

  The polyamide resin composition obtained by the production method of the present invention is subjected to a normal molding method (for example, hot melt molding methods such as injection molding, extrusion molding, blow molding, and sintering molding), thereby It can be a molded product. Moreover, it can also be set as a thin film by melt | dissolving the polyamide resin composition obtained by this invention in the organic-solvent solution, and attaching | subjecting to a casting method.

  The resin composition of the present invention is suitably used in the electric / electronic equipment field, the automobile field, the machine field, and the like.

  EXAMPLES Next, the present invention will be described more specifically with reference to examples, but the present invention is not limited thereto.

The raw materials used in Examples and Comparative Examples are shown below.
1. Raw material (1) Monomer A-1 constituting the polyamide resin: ε-caprolactam (manufactured by Ube Industries)
A-2: Adipic acid / hexamethylenediamine equimolar salt

(2) Fibrous clay mineral B-1: Sepiolite (manufactured by TOLSA, trade name “PANGEL HV”)
B-2: Palygorskite (made by Showa KDE, trade name “POLEISY”)

(3) Viscosity modifier C-1: polyether carboxylic acid amine salt (temperature X: 240 ° C.)
C-2: Polyether phosphate ester amine salt (temperature X: 260 ° C.)
C-3: Polyether phosphate ester (temperature X: 200 ° C.)

(4) Viscosity modifier D-1 other than (3) above: Tetramethylammonium chloride (quaternary ammonium salt, temperature X: 230 ° C.)

  The evaluation methods used in the examples and comparative examples are shown below. Of the following evaluation methods, (3) to (5) were evaluated using test pieces injection-molded at a cylinder temperature of 250 ° C and a mold temperature of 80 ° C.

2. Test method (1) Temperature (temperature X) at which the thermogravimetric reduction rate measured in air at a heating rate of 10 ° C./min is 5% by mass
5 mg of a measurement sample was placed on a sample stage and heated from 20 ° C. to 500 ° C. at a temperature rising rate of 10 ° C./min in an air atmosphere, and the temperature when the weight reduction rate became 5% by mass was manufactured by PERKIN ELMER. It measured by "TGA-7".

(2) Rotational viscosity (Pa · s)
Using a B-type viscometer (manufactured by Toki Sangyo Co., Ltd.), the rotational viscosity at 80 ° C. and 0.3 rpm was measured. In the measurement, the spindle No. 1 was used.

(3) Bending strength (MPa)
The bending strength (MPa) was measured in accordance with ISO178 for a test piece having a length of 100 mm, a width of 10 mm, and a thickness of 4 mm obtained by injection molding. In the present invention, those having a pressure of 150 MPa or more are assumed to be practically usable.

(4) Flexural modulus (GPa)
The bending elastic modulus (GPa) of a test piece having a length of 100 mm, a width of 10 mm, and a thickness of 4 mm obtained by injection molding was measured according to ISO178. In the present invention, those having 4 GPa or more are assumed to be practically usable.

(5) Dispersion residual ratio (%)
In the following Examples and Comparative Examples, when the dispersion, which was the pre-polymerization stage, was charged into the autoclave, the mass of the dispersion remaining in the dispersion container was weighed, and the ratio to the total amount of raw materials (mass) was calculated.

(6) Quantification of component (C) in the obtained resin composition The polyamide resin composition pellet obtained by the step (ii) is subjected to a nuclear magnetic resonance analyzer (trade name “JNM-ECA500” manufactured by JEOL Ltd.). ¹ H-NMR measurement was performed at a measurement frequency of 500 MHz.

Example 1
90 parts by mass of ε-caprolactam (A-1) was put in a container and made into a uniform melt while heating at 80 ° C. Next, using a homomixer (trade name “TK. Homomixer MARKII20” manufactured by Primix Co., Ltd.), the mixture was stirred at a rotational speed of 4000 rpm, and 10 parts by mass of sepiolite (B-1) and 10 parts by mass of poly (s) while stirring. Ether carboxylate amine salt [100 parts by mass with respect to 100 parts by mass of (C-1) sepiolite (B-1)] was added and stirring was continued to obtain a dispersion. The rotational viscosity increased with time, and the rotational viscosity at the start of stirring was 5 Pa · s, but the rotational viscosity after 4 hours was 12 Pa · s.

  Subsequently, when the obtained dispersion liquid was thrown into the autoclave, the residual ratio of the dispersion liquid was 3%. The autoclave was polymerized for 1 hour while stirring at an internal temperature of 260 ° C. After completion of the polymerization, the polymer taken in a strand form from the bottom drain valve of the autoclave was cooled and solidified in a hot tub, and cut into pellets with a pelletizer. The obtained pellets were refined with hot water at 95 ° C. for 24 hours to remove unreacted monomers and oligomers. Then, it was dried at 80 ° C. for 24 hours, and further vacuum dried at 80 ° C. for 48 hours to obtain a polyamide resin composition.

  The obtained polyamide resin composition pellets were injection molded at a cylinder temperature of 250 ° C. and a mold temperature of 80 ° C. using an injection molding machine (trade name “EC-100” manufactured by Toshiba Machine Co., Ltd.). Produced. Table 1 shows the evaluation results for the obtained molded product.

(Examples 2-9)
As shown in Table 1, the blending amount of the monomer constituting the polyamide resin (A), the type and blending amount of the fibrous clay mineral (B), and the blending amount of the organic carboxylic acid amine salt (C) were changed. In the same manner as in Example 1, a dispersion and a polyamide resin composition were obtained, and the polyamide resin composition was injection molded to obtain a molded product. Evaluation was performed about the obtained molded article. The evaluation results are shown in Table 1.

(Example 10)
70 parts by mass of adipic acid / hexamethylenediamine equimolar salt (A-2) is put in a container and heated at 205 ° C. under a nitrogen atmosphere until a homogeneous solution is obtained (product name “T” manufactured by Primix Co., Ltd.). K. Homomixer MARK II 20 "), and stirring and mixing at a rotational speed of 4000 rpm, 30 parts by mass of sepiolite (B-1) and 10 parts by mass of a polyether carboxylic acid amine salt [(C- 1) 33 parts by mass of 100 parts by mass of sepiolite (B-1)] was added and stirring was continued to obtain a dispersion. The rotational viscosity increased with the passage of time, and the rotational viscosity at the start of stirring was 5 Pa · s, but the rotational viscosity after 4 hours was 43 Pa · s.

  Subsequently, when the obtained dispersion was put into an autoclave, the residual ratio of the dispersion was 6%. While stirring the autoclave at an internal temperature of 230 ° C., it is heated until the internal pressure reaches 18 MPa. After reaching that pressure, the pressure is gradually released, and when the heating reaches 280 ° C., the pressure is released to normal pressure. Polymerization was performed for 2 hours.

  After the completion of the polymerization, the polymer taken on the strand from the bottom discharge valve of the autoclave was cooled and solidified in a hot tub, and cut into pellets with a pelletizer. Then, it was vacuum-dried at 80 ° C. for 48 hours.

  The obtained polyamide resin composition pellets were injection molded at a cylinder temperature of 270 ° C. and a mold temperature of 80 ° C. using an injection molding machine (trade name “EC-100” manufactured by Toshiba Machine Co., Ltd.). Produced. Table 1 shows the evaluation results for the obtained molded product.

(Example 11)
A dispersion and a polyamide resin composition were obtained in the same manner as in Example 2 except that the internal temperature of the autoclave was set to 220 ° C. and polymerized for 5 hours, and the polyamide resin composition was injection molded to obtain a molded product. Evaluation was performed about the obtained molded article. The evaluation results are shown in Table 1.

(Example 12)
A dispersion and a polyamide resin composition were obtained in the same manner as in Example 2 except that the internal temperature of the autoclave was changed to 290 ° C. for 5 hours, and a molded product was obtained by injection molding the polyamide resin composition. Evaluation was performed about the obtained molded article. The evaluation results are shown in Table 1.

(Example 13)
A dispersion and a polyamide resin composition were obtained in the same manner as in Example 2 except that the polyether phosphate amine salt (C-2) was used as the viscosity modifier (C), and the polyamide resin composition was injected. Molded to obtain a molded product. Evaluation was performed about the obtained molded article. The evaluation results are shown in Table 1.

(Example 14)
A dispersion and a polyamide resin composition were obtained in the same manner as in Example 2 except that the polyether phosphate ester (C-3) was used as the viscosity modifier (C), and the polyamide resin composition was injection molded. A molded product was obtained. Evaluation was performed about the obtained molded article. The evaluation results are shown in Table 1.

(Comparative Example 1)
A resin composition and a molded article were obtained and evaluated in the same manner as in Example 1 except that the organic carboxylic acid amine salt which is the viscosity modifier (C) defined in the present invention was not used. The evaluation results are shown in Table 1.

(Comparative Examples 2-6)
As shown in Table 1, the blending amount of the monomer constituting the polyamide resin (A), the blending amount of the fibrous clay mineral (B), the type and blending amount of the viscosity modifier (C) are changed, or the component ( A resin composition and a molded product were obtained in the same manner as in Example 1 except that (D-1) was used instead of C), and the evaluation was performed. The evaluation results are shown in Table 1.

  As is clear from Table 1, in Examples 1 to 14, the increase in the viscosity of the dispersion can be sufficiently reduced, and the polyamide resin composition is produced with high productivity by polymerizing the dispersion. I was able to. Furthermore, the obtained polyamide resin composition had a low density and was excellent in both bending strength and bending elastic modulus.

  In Comparative Example 1, since the organic carboxylic acid amine salt, which is the viscosity modifier (C) defined in the present invention, was not blended, the viscosity of the obtained dispersion was high and the dispersion residual ratio was increased. Therefore, it has been impossible to produce a polyamide resin composition with high productivity.

  In Comparative Example 2, since the blending amount of the fibrous clay mineral (B) was too small, the bending characteristics of the obtained polyamide resin composition were insufficient.

  In Comparative Example 3, since the blending amount of the fibrous clay mineral (B) was excessive, the rotational viscosity of the obtained dispersion liquid was high and the dispersion liquid residual ratio was increased. Therefore, it has been impossible to produce a polyamide resin composition with high productivity.

  In Comparative Example 4, since the blending amount of the organic carboxylic acid amine salt that is the viscosity modifier (C) defined in the present invention was too small, the resulting dispersion had a high rotational viscosity and a large dispersion residual ratio. became. Therefore, it has been impossible to produce a polyamide resin composition with high productivity.

  In Comparative Example 5, the amount of the organic carboxylic acid amine salt, which is the viscosity modifier (C) defined in the present invention, was excessive, so that the viscosity of the dispersion was sufficiently low, but the obtained polyamide resin composition A large amount of component (C) remained inside. Therefore, the bending property of the obtained polyamide resin composition became insufficient.

  In Comparative Example 6, since the predetermined viscosity modifier was not used, the rotational viscosity of the obtained dispersion was high and the dispersion residual ratio was large. Therefore, it has been impossible to produce a polyamide resin composition with high productivity.

Claims (6)

A method for producing a polyamide resin composition, comprising the following steps (i) and (ii) in this order:
Step (i): The monomer constituting the polyamide resin (A) is heated and melted at a temperature equal to or higher than its melting point, and dispersed by blending the fibrous clay mineral (B) and the viscosity modifier (C) while stirring. The step of obtaining a liquid, wherein the blending ratio (A) / (B) of the polyamide resin (A) and the fibrous clay mineral (B) is 50/50 to 95/5, and the viscosity modifier (C) The process whose usage-amount is 0.5-100 mass parts with respect to 100 mass parts of fibrous clay minerals (B).
Step (ii): A step of polymerizing the dispersion obtained in step (i) to obtain a resin composition containing a polyamide resin (A), a fibrous clay mineral (B), and a viscosity modifier (C).   Sepiolite and / or palygorskite is used as fibrous clay mineral (B), The manufacturing method of the polyamide resin composition of Claim 1 characterized by the above-mentioned.   The method for producing a polyamide resin composition according to claim 1 or 2, wherein an organic carboxylic acid amine salt, a polyether phosphate ester or an amine salt thereof is used as the viscosity modifier.   The polyamide resin according to any one of claims 1 to 3, wherein the temperature X at which the thermal weight reduction rate of the viscosity modifier (C) used is 5 mass% is less than the polymerization temperature in step (ii). A method for producing the composition.   In the step (i), stirring is performed in an environment of 80 ° C and 0.3 rpm so that the rotational viscosity of the dispersion measured with a B-type viscometer is 0.01 to 300 Pa · s. The manufacturing method of the polyamide resin composition in any one of -4. It contains a polyamide resin (A), a fibrous clay mineral (B), and a viscosity modifier (C), the mass ratio of (A) / (B) is 50/50 to 95/5, and the viscosity modifier ( The polyamide resin composition, wherein the content of C) is 0.0001 to 10 parts by mass with respect to 100 parts by mass of the fibrous clay mineral (B).