WO2011070959A1

WO2011070959A1 - Polyamide resin composition, and method for producing polyamide resin composition

Info

Publication number: WO2011070959A1
Application number: PCT/JP2010/071537
Authority: WO
Inventors: 辰典正木
Original assignee: ユニチカ株式会社
Priority date: 2009-12-09
Filing date: 2010-12-02
Publication date: 2011-06-16
Also published as: TW201130918A; JP5832296B2; JPWO2011070959A1

Abstract

Disclosed is a polyamide resin composition containing 70 to 99.5 parts by mass of a polyamide resin (A) and 0.5 to 30 parts by mass of a fibrous clay mineral (B), which is characterized in that monodispersed fibrous crystals of the fibrous clay mineral (B) and/or aggregates of said monodispersed fibrous crystals are dispersed within the polyamide resin (A) in the following state (I) and state (II); state (I) being a state in which the fiber length of each monodispersed fibrous crystal is 0.01 to 40µm, and the maximum outer diameter of the aggregates of the monodispersed fibrous crystals is 0.01 to 40µm; and state (II) being a state in which the shortest distance between each monodispersed fibrous crystal, the shortest distance between each aggregate of the monodispersed fibrous crystals, and the shortest distance between one monodispersed fibrous crystal and the aggregates of the monodispersed fibrous crystals are all between 1 and 100nm.

Description

Polyamide resin composition and method for producing polyamide resin composition

The present invention relates to a polyamide resin composition having a low density, excellent mechanical properties, and a simplified manufacturing process as compared with a polyamide resin reinforced with conventional fibers, and a method for producing the polyamide resin composition.

As a method for reinforcing the mechanical strength of a polyamide resin, it is already widely known that the polyamide resin is blended with a fiber such as glass fiber or carbon fiber or an inorganic filler such as calcium carbonate as a reinforcing material to form a resin composition. It has been.

However, since such a reinforcing material has poor affinity with the polyamide resin, there is a problem that the toughness of the obtained polyamide resin composition is lowered. Furthermore, a molded product obtained by molding a polyamide resin composition reinforced with fibers has a problem that warpage becomes large. Further, in a polyamide resin composition reinforced with an inorganic filler, mechanical strength and heat resistance are not improved unless a large amount of the inorganic filler is blended. Therefore, there has been a problem that the density is remarkably increased and the mass of the resulting molded body is increased.

In addition, when it is considered that the monomer constituting the polyamide resin is a starting material, a two-step process is required to obtain a reinforced polyamide resin composition as described above. That is, a step of polymerizing a polyamide monomer to obtain a polyamide resin and a step of mixing the polyamide resin obtained by polymerization and a reinforcing material are required. Therefore, from the viewpoint of simplifying the manufacturing process, there is a problem that it is industrially disadvantageous.

As an attempt to solve the above problems, a method has been proposed in which a polyamide resin composition is obtained by polymerizing a layered silicate clay mineral represented by montmorillonite or mica in a polyamide monomer. In such a case, a resin composition in which both are finely and uniformly dispersed can be obtained by allowing the polyamide chain to penetrate between the layers of the layered silicate clay mineral. For example, JP62-74957A and Japanese Patent No. 2747019 describe a resin composition comprising a polyamide resin and montmorillonite and a method for producing the resin composition. Japanese Patent No. 2941159 and Japanese Patent No. 3409921 describe a resin composition comprising a polyamide resin and mica and a method for producing the resin composition.

The polyamide resin composition obtained in the above-mentioned literature has a low density and excellent bending characteristics as compared with a polyamide resin composition reinforced with glass fibers and other inorganic fillers. However, the impact resistance of the resulting polyamide resin composition is very low, and its usage is considerably limited.

These layered silicate clay minerals are prone to cleavage (cracking along a specific direction of crystals that occur due to low bonding strength). Therefore, even when a small amount of layered silicate clay mineral is added, the melt viscosity of the polyamide resin composition obtained in the above-mentioned literature increases. As a result, it becomes difficult to dispense the polyamide resin composition from the reaction vessel after completion of the polymerization. Therefore, in order to recover the polyamide resin composition from the reaction vessel in a high yield, there has been a problem that the layered silicate clay mineral can be blended in the polyamide resin composition only in a few mass%.

On the other hand, JP2008-280376A describes a method for improving the impact resistance of a polyamide resin composition obtained by blending a swellable layered silicate previously treated with a coupling agent into a polyamide resin. However, even with such a method, the impact resistance could not be improved to a level that can withstand practical use.

In order to solve such a problem, a polyamide resin composition using a clay mineral (for example, fibrous viscosity mineral) that is not layered has been studied. When a clay mineral that is not layered is used, it can be blended at a high concentration. For example, even when added at the time of polymerization of a polyamide resin, it is blended at a high concentration.

For example, JP63-251461A and JP6-84435B describe a resin composition comprising a polyamide resin and a fibrous double-chain structure type clay mineral, and a method for producing the same. In the polyamide resin composition obtained by JP63-251461A and JP6-84435B, it is possible to add a clay mineral at a higher concentration than when a layered silicate clay mineral is used.

However, it is a polyamide resin composition obtained by using an untreated fibrous double-chain structure type clay mineral such as JP63-251461A, or a water suspension comprising a fibrous double-chain structure type clay mineral such as JP6-84435B. Even if it is a polyamide resin composition obtained by polymerizing with a nylon monomer after blending a coupling agent with the suspension, the dispersion state of the clay mineral in the polyamide resin is poor and the reinforcing effect is insufficient. Met. Furthermore, the impact resistance was not as high as that of polyamide resin reinforced with glass fiber or carbon fiber.

Accordingly, an object of the present invention is to solve the above-mentioned problems, a polyamide resin composition having a low density, excellent mechanical properties, and a simplified production process, and a method for producing the polyamide resin composition Is to provide.

As a result of intensive studies to solve the above problems, the present inventor has found that a polyamide resin composition in which a fibrous clay mineral is dispersed in a specific state in a polyamide resin can achieve the above object, and the present invention. Reached. Furthermore, when a specific coupling agent was used, it discovered that impact resistance improved and arrived at this invention.

That is, the gist of the present invention is the following (1) to (8).
(1) A polyamide resin composition containing 70 to 99.5 parts by mass of polyamide resin (A) and 0.5 to 30 parts by mass of fibrous clay mineral (B), wherein the fibers are contained in the polyamide resin (A). The fibrous crystals in which the clay clay mineral (B) is monodispersed and / or the aggregates in which the monodispersed fibrous crystals are aggregated are dispersed in the following states (I) and (II): Polyamide resin composition.
(I) The fiber length of one monodispersed fibrous crystal is 0.01 to 40 μm, and the maximum outer size of the aggregate obtained by agglomerating monodispersed fibrous crystals is 0.01 to 40 μm.
(II) The shortest distance between monodispersed fibrous crystals, the shortest distance between aggregates of monodispersed fibrous crystals, and one monodispersed fibrous crystal and monodispersed fibrous crystals The shortest distance between the aggregated aggregates is 1 to 100 nm.
(2) 0.05 to 5 parts by mass of the coupling agent (C) is contained with respect to 100 parts by mass in total of the polyamide resin (A) and the fibrous clay mineral (B) (1) Polyamide resin composition.
(3) The polyamide resin composition according to (1) or (2), wherein the fibrous clay mineral (B) is sepiolite and / or palygorskite.
(4) The polyamide resin composition according to (2) or (3), wherein the coupling agent (C) is a silane coupling agent containing a reactive group selected from an epoxy group, a ureido group and an isocyanate group object.
(5) After melting 70 to 99.5 parts by mass of the monomer constituting the polyamide resin (A) and 0.01 to 5 parts by mass of the acid (D) at a temperature T equal to or higher than the melting point of the monomer, the fibrous clay is further added. A step (i) of mixing 0.5 to 30 parts by mass of the mineral (B) at a shear rate of 1000 to 20000 sec ⁻¹ , and a step (ii) of melt-polymerizing the mixture obtained in the step (i), Polyamide resin composition in which monodispersed fibrous crystals of fibrous clay mineral (B) and / or aggregates of monodispersed fibrous crystals are dispersed in the following states (I) and (II): A process for producing a polyamide resin composition, characterized in that
(I) The fiber length of one monodispersed fibrous crystal is 0.01 to 40 μm, and the maximum outer diameter of the aggregate obtained by agglomerating monodispersed fibrous crystals is 0.01 to 40 μm.
(II) The shortest distance between monodispersed fibrous crystals, the shortest distance between aggregates of monodispersed fibrous crystals, and one monodispersed fibrous crystal and monodispersed fibrous crystals The shortest distance between the aggregated aggregates is 1 to 100 nm.
(6) In step (i), 0.05 to 5 parts by mass of the coupling agent (C) is added to 100 parts by mass in total of the monomer constituting the polyamide resin (A) and the fibrous clay mineral (B). The method for producing a polyamide resin composition according to (5), which comprises mixing.
(7) After step (ii), the coupling agent (C) is added in an amount of 0.05 to 5 masses with respect to a total of 100 mass parts of the monomer constituting the polyamide resin (A) and the fibrous clay mineral (B). (5) The manufacturing method of the polyamide resin composition characterized by including the process (iii) which melt-kneads by adding a part.
(8) In the step (i), the mixing is carried out so that the rotational viscosity measured with a B-type viscometer at a temperature T after a mixing time of 0.5 hours or more is 1 to 500 Pa · s (5) ) To (7) A method for producing any one of the polyamide resin compositions.

According to the present invention, it is possible to provide a polyamide resin composition having a low density, excellent mechanical properties, and a simplified manufacturing process. Furthermore, according to this invention, the manufacturing method of this polyamide resin composition can be provided.

It is the schematic which shows the dispersion state of the fibrous clay mineral (B) used for this invention. It is the schematic which shows the fiber length or maximum outer dimension of the fibrous clay mineral (B) in a dispersion state. It is the schematic which shows the shortest distance of the fibrous clay mineral (B) in a dispersion state.

Hereinafter, the present invention will be described in detail.

The polyamide resin composition of the present invention contains a fibrous clay mineral (B) [hereinafter simply referred to as “component (B)” in the polyamide resin (A) [hereinafter sometimes simply referred to as “component (A)”]. May be referred to] are distributed.

The component (A) in the present invention is a polymer having an amide bond in the main chain, with aminocarboxylic acid, lactam, or diamine and dicarboxylic acid as main raw materials.

Examples of the aminocarboxylic acid include 6-aminocaproic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid and the like. Examples of the lactam include ε-caprolactam, ω-undecanolactam, and ω-laurolactam.

Examples of the diamine include tetramethylene diamine, hexamethylene diamine, undecamethylene diamine, and dodecamethylene diamine. Examples of the dicarboxylic acid include adipic acid, suberic acid, sebacic acid, dodecanedioic acid and the like. These diamines and dicarboxylic acids can also be used as a pair of salts.

Preferred 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), polydecamide (nylon 12), polycaproamide / polydodecamide copolymer (nylon 6) / 12), polyhexamethylene sebacamide (nylon 610), polyhexamethylene dodecamide (nylon 612), polyundecamethylene adipamide (nylon 116), and mixtures thereof, or polymers thereof. It is done.

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

The component (B) in the present invention is preferably a fibrous hydrous magnesium silicate mineral. Among these, sepiolite and palygorskite are particularly preferably used from the viewpoint of easy dispersion in the polyamide resin and easy control of the rise of the molten clay of the obtained polyamide resin composition.

Sepiolite is a natural mineral containing Mg ₈ H ₂ (SiO ₄ O ₁₁ ) · 3H ₂ O as a main component, and palygorskite contains Mg ₈ Al ₂ Si ₈ O ₂₀ (OH ₂ ) · 8H ₂ O as a main component. Is a natural mineral. In the palygorskite, magnesium may be replaced with iron or aluminum.

The component (B) has a thermal weight loss rate of preferably 1 to 80% by mass, more preferably 2 to 55% by mass when the temperature is increased from 20 ° C. to 200 ° C. in a nitrogen atmosphere. It is particularly preferably 3 to 30% by mass. The reason will be described below.

In component (B), components that decrease when the temperature is raised from 20 ° C. to 200 ° C. are mainly adsorbed water and zeolite water. When a large amount of adsorbed water or zeolite water is present in the component (B), the monomer constituting the component (A) tends to enter the component (B) due to the hydrophilicity of the monomer itself. As a result, the dispersion of the component (B) can be promoted. That is, the dispersibility is further improved when the thermal weight reduction rate when the temperature is raised from 20 ° C. to 200 ° C. is 1% by mass or more. On the other hand, if there is a large amount of adsorbed water or zeolite water and the thermal weight loss rate exceeds 80% by mass, the component (B) becomes a gel and difficult to disperse in the monomer solution constituting the component (A) in step (i). This is not preferable.

The basic structure of component (B) will be described below.

Component (B) has a three-layer structure in which an octahedral magnesium oxide layer is a central layer and a tetrahedral silicate layer is disposed on both sides thereof. Since this three-layer structure extends along the X-axis direction (fiber length direction), the component (B) crystals are fibrous (fibrous crystals). Moreover, a some fibrous crystal may aggregate along a fiber direction.

Also, since the tetrahedral silicate layer is inverted and bonded on the Z axis every few units, the octahedral magnesium oxide layer becomes a discontinuous layer and forms zeolite pores in the fiber cross section. The component (B) has a large number of silanol groups (Si—OH groups) along the X-axis direction. Therefore, it has a property that a highly polar substance such as water can easily enter the gap between the zeolite pores and the particles.

As described above, the component (B) in the present invention is porous while being fibrous as compared with other clay minerals. Therefore, while being bulky, it is excellent in affinity with the polyamide resin, can be blended in the resin composition without becoming high density, and the bending characteristics can be effectively improved.

That is, the component (B) needs to be sufficiently dispersed in the component (A), and a fibrous crystal in which the component (B) is monodispersed in the component (A) or a plurality of fibrous crystals are bundled. It is dispersed in the form of aggregates. Thereby, the resin composition of the present invention has a low density and an excellent bending property.

In the present invention, the sufficiently dispersed state means that the component (B) in the component (A) is monodispersed fibrous crystals or monodispersed fibrous crystals as shown in FIG. This is a state of agglomerated aggregates and satisfies the following (I) and (II) at the same time.
(I) The fiber length of one monodispersed fibrous crystal is 0.01 to 40 μm, preferably 0.1 to 20 μm. The maximum outer dimension of the aggregate obtained by agglomerating monodispersed fibrous crystals is 0.01 to 40 μm, preferably 0.1 to 20 μm.
(II) The shortest distance between monodispersed fibrous crystals, the shortest distance between aggregates of monodispersed fibrous crystals, and one monodispersed fibrous crystal and monodispersed fibrous crystals The shortest distance between the agglomerated aggregates is 1 to 100 nm, preferably 10 to 50 nm.

In the above (I), if the fiber length is less than 0.01 μm, there is a problem that the reinforcing effect of the component (A) becomes insufficient. On the other hand, if it exceeds 40 μm, when a polyamide resin composition is used, cracks are likely to occur when stress is applied, and the mechanical strength is lowered, which is not preferable.

In the above (I), if the maximum outer dimension of the aggregate is less than 0.01 μm, there is a problem that the reinforcing effect of the component (A) becomes insufficient. On the other hand, if it exceeds 40 μm, when a polyamide resin composition is used, cracks are likely to occur when stress is applied, and the mechanical strength is lowered, which is not preferable.

In the above (I), the fiber length of one monodispersed fibrous crystal and the maximum outer dimension of the aggregate of monodispersed fibrous crystals are determined by observing the inside of the resin composition with a transmission electron microscope. The measured value is referred to, and a detailed measuring method will be described later.

FIG. 2 shows the fiber length of one monodispersed fibrous crystal and the maximum outer size of the aggregate in which the monodispersed fibrous crystals are aggregated. In FIG. 2, (a) shows the maximum outer dimension of the aggregate in which monodispersed fibrous crystals are aggregated. (B) shows the fiber length of one monodispersed fibrous crystal.

In the above (II), the shortest distance between monodispersed fibrous crystals, the shortest distance between aggregates of monodispersed fibrous crystals, and one monodispersed fibrous crystal and monodispersed fibers If the shortest distance between the aggregates of the aggregated crystals is less than 1 nm, there is a problem that the fluidity of the polyamide resin composition is extremely lowered and the molding process becomes difficult. On the other hand, when it exceeds 100 nm, the reinforcing effect of the component (A) by the component (B) decreases, and sufficient bending characteristics cannot be imparted.

In the present invention, the shortest distance between monodispersed fibrous crystals, the shortest distance between aggregates of one monodispersed fibrous crystal, and one monodispersed fibrous crystal and monodispersed fibers The shortest distance between the aggregates of the aggregated crystals is the observation of the inside of the resin composition with a transmission electron microscope, and the aggregates of monodispersed fibrous crystals and aggregated monodispersed fibrous crystals , And an aggregate obtained by agglomerating one monodispersed fibrous crystal and a monodispersed fibrous crystal, which has the shortest distance, and a detailed measuring method will be described later.

FIG. 3 shows the shortest distance between monodispersed fibrous crystals in the present invention, the shortest distance between aggregates of one monodispersed fibrous crystal, and one monodispersed fibrous crystal and monodisperse. It shows the shortest distance between the aggregates of the aggregated fibrous crystals. In FIG. 3, (c) shows the shortest distance between one monodispersed fibrous crystal and an aggregate obtained by agglomerating monodispersed fibrous crystals. (D) shows the shortest distance between monodispersed fibrous crystals. (E) shows the shortest distance between aggregates of one monodispersed fibrous crystal.

In the present invention, the mixing ratio of the component (A) and the component (B) in the resin composition needs to be 99.5 / 0.5 to 70/30 (parts by mass), preferably 96 / It is 4 to 75/25 (parts by mass), more preferably 93/7 to 80/20 (parts by mass). The reinforcement | strengthening effect of a component (A) becomes inadequate that the compounding quantity of a component (B) is less than 0.5 mass part. On the other hand, when it exceeds 30 mass parts, there exists a problem that the obtained resin composition becomes weak.

In the present invention, in addition to the component (A) and the component (B), a coupling agent (C) [hereinafter sometimes simply referred to as “component (C)”] may be contained. The component (C) is a compound containing a functional group having affinity or reactivity with the component (A) and the component (B). Component (C) suppresses interfacial breakage between component (A) and component (B) and improves impact resistance. In particular, since (B) has a large amount of Si—OH on its surface, the effect of improving impact resistance is very large compared to other inorganic fillers.

Examples of compounds that can be used as the component (C) include silane coupling agents and titanate coupling agents. Especially, a silane coupling agent is preferable from a reactive viewpoint with a component (B). Furthermore, an alkoxysilane compound is preferable from the viewpoint of reactivity with the component (B).

Specific examples of such alkoxysilane compounds include N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, N-2- (Aminoethyl) -3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N- (1,3-dimethylbutylidene) propylamine, Amino group-containing alkoxysilane compounds such as N-phenyl-3-aminopropyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyl Methyldiethoxysilane, 3-glycidoxyp Epoxy group-containing alkoxysilane compounds such as pyrtriethoxysilane, vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane compounds such as vinyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyl Acryloxy group-containing alkoxysilane compounds such as dimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, ureido group-containing alkoxysilane compounds such as 3-ureidopropyltriethoxysilane, 3-isocyanatopropyl Examples include isocyanate group-containing alkoxysilane compounds such as triethoxysilane. Among these, an epoxy group-containing alkoxysilane, a ureido group-containing alkoxysilane, and an isocyanate group-containing alkoxysilane are particularly preferable from the viewpoint of reactivity with the component (A).

In the present invention, the amount of component (C) is preferably 0.05 to 5 parts by mass, more preferably 0.1 to 100 parts by mass in total of component (A) and component (B). -3 parts by mass, particularly preferably 0.5-2 parts by mass. Within the above range of blending, the blending amount increases and the impact resistance tends to improve, and the melt viscosity of the resulting resin composition tends to increase. If the amount of component (C) is less than 0.05 parts by mass, the effect of improving the interaction between component (A) and component (B) will be insufficient, and the impact resistance may not be improved. On the other hand, when the amount exceeds 5 parts by mass, the increase in melt viscosity of the component (A) becomes remarkable, not only the productivity is lowered, but also the toughness of the resulting resin composition is impaired and the impact resistance is lowered. There is.

Next, a method for producing the polyamide resin composition of the present invention will be described.

The following method can be used as the method for producing the polyamide resin composition of the present invention.

That is, after the monomer constituting the polyamide resin (A) and the acid (D) are melted at a temperature T equal to or higher than the melting point of the monomer, the fibrous clay mineral (B) is further mixed at a shear rate of 1000 to 20000 sec ⁻¹ . It includes a step (i) (that is, a mixing step) and a step (ii) (that is, a melt polymerization step) in which the mixture obtained in the step (i) is melt-polymerized. That is, it is a method in which a mixture of the monomer constituting component (A), component (B) and acid (D) is prepared to form a slurry, and the mixture is subjected to melt polymerization. According to this manufacturing method, the effect of (dispersing the fibrous clay mineral (B) sufficiently and obtaining a resin composition excellent in bending properties) can be achieved.

In the production method of the present invention, the blending ratio of component (A) to component (B) needs to be 99.5 / 0.5 to 70/30 (parts by mass), preferably 96/4 to 75/25 (parts by mass), more preferably 93/7 to 80/20 (parts by mass). The reinforcement | strengthening effect of a component (A) becomes inadequate that the compounding quantity of a component (B) is less than 0.5 mass part. On the other hand, when it exceeds 30 mass parts, there exists a problem that the obtained resin composition becomes weak.

Process (i) will be described.

In step (i), the acid (D) plays a role of acting as a catalyst when the monomer constituting the component (A) is polymerized. In addition, when component (B) is the above-mentioned sepiolite or palygorskite, acid (D) reacts with the monomer constituting component (A) in step (i), and the resulting reactant is It is possible to promote the dispersibility of the component (B) by penetrating into the component (B) having a large number of silanol groups.

The acid (D) may be either an inorganic acid or an organic acid as long as the pKa (25 ° C., value in water) is 6 or less. Specific examples of the inorganic acid include phosphoric acid, phosphorous acid, hydrochloric acid, sulfuric acid, nitric acid and the like. Examples of the organic acid include formic acid, acetic acid, monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, trifluoroacetic acid, propionic acid, benzoic acid, p-toluenesulfonic acid, N-formyl-ε-aminocaproic acid and the like. Among the above, phosphorous acid is preferable from the viewpoint of reactivity with the monomer constituting the component (A).

The amount of the acid (D) used must be 0.01 to 5 parts by mass, and 0.1 to 1 part by mass with respect to 100 parts by mass of the monomer constituting the component (A). preferable. When the amount of the acid (D) used is less than 0.01 parts by mass, the effect of promoting the dispersion of the component (B) may not be sufficiently exhibited. Moreover, the polymerization rate of a component (A) may become slow. On the other hand, when it exceeds 5 parts by mass, a polyamide resin (A) having a high degree of polymerization cannot be obtained, and problems such as corrosion of the reaction vessel may occur.

In step (i), it is preferable to mix the above-mentioned coupling agent (C) together with the fibrous clay mineral (B). By mixing the component (C) in the step (i), affinity or adhesion with the component (A) and the component (B) can be improved, and the component (A) and the component (B) can be improved by the component (C). ) Is suppressed, and the impact resistance is improved. In particular, since (B) has a large amount of Si—OH on its surface, the effect of improving impact resistance is very large compared to other inorganic fillers.

When component (C) is added in step (i), the reaction between component (C), component (A), and component (B) occurs sufficiently. Therefore, even if the compounding amount of the component (C) is small, the impact resistance can be sufficiently improved, and furthermore, the production process can be simplified, which is very useful industrially. However, if the amount of component (C) is large, caution must be exercised because thickening of the resin may occur during step (ii). In this case, the inside of the polymerization apparatus can be discharged from the polymerization apparatus by increasing the pressure.

In step (i), the rotational viscosity measured with a B-type viscometer at a temperature T after the mixing time of 0.5 hours or more is preferably 1 to 500 Pa · s, more preferably 5 to 400 Pa · s, particularly The pressure is preferably 10 to 300 Pa · s. In the said process (i), when rotational viscosity exceeds 500 Pa.s, the fluidity | liquidity of a mixture will fall extremely. Therefore, it becomes difficult for the mixture to cause a uniform reaction in the next step (ii), and the polymerization may be insufficient. Furthermore, the transition from the step (i) to the step (ii) becomes difficult, leading to a decrease in productivity. On the other hand, when it is less than 1 Pa · s, the dispersion of the component (B) is deteriorated, so that the reinforcing effect of the component (A) may be insufficient.

That is, in the step (i), when the rotational viscosity measured with a B-type viscometer at a temperature T after 0.5 hours or more of mixing time is 1 to 500 Pa · s, the component (B) in the component (A) This dispersion state satisfies the above conditions (I) and (II).

In order to control the viscosity of this mixture, it is necessary to appropriately select the blending amount of component (B) and the mixing time (processing time).

In step (i), by adjusting the shear rate and mixing time, the rotational viscosity measured with a B-type viscometer at a temperature T after 0.5 hours or more of mixing time can be controlled within the above-mentioned range.

Here, for example, when using a rotor / stator type stirrer such as a homomixer, the shear rate is the distance (clearance) of a slight gap formed between the rotor / stator and the rotational speed of stirring of the rotor (stirring blade). It is a numerical value obtained by the following equation.

Shear rate (sec ⁻¹ ) = [stirring blade diameter (m) × π × stirring rotation speed (rpm) / 60] / clearance (m)
Moreover, when using the propeller mixer which does not have a stator for stirring apparatus itself, said shear rate can be calculated | required by making into clearance the distance of a propeller (stirring blade) front-end | tip and a stirring tank. In this case, the shape of the stirring tank is preferably a cylindrical shape in order to increase the stirring efficiency. Moreover, in order to suppress scattering of the mixture subjected to stirring to the outside of the stirring tank, it is preferable to have a structure capable of appropriately suppressing scattering of the mixture by a shielding plate or the like.

Shear rate in step (i) is required to be 1000 ~ 20000sec ^-1, preferably from 2000 ~ 17000sec ^-1, more preferably 3000 ~ 15000sec ^-1. When the shear rate is less than 1000 sec ⁻¹ , there is a problem that the dispersion of the fibrous clay mineral (B) becomes insufficient. On the other hand, if it exceeds 20000 sec ⁻¹ , there is a problem that it is difficult to control the rotational viscosity because the shear is too strong.

In step (i), in order to give the above-mentioned shear rate to the mixture, for example, it is preferable to use a stirrer capable of controlling the clearance in the range of 0.5 to 5 mm as a stirrer.

Further, in order to give the mixture a shear rate in the above range in the step (i), it is preferable to control the rotation speed of the stirring in the step (i) in the range of 100 to 10,000 rpm.

The mixing time in step (i) is preferably 0.5 to 6 hours, and more preferably 1 to 4 hours, from the viewpoint of controlling the rotational viscosity within the above range.

The form when the component (B) is used in the step (i) is not particularly limited as long as the dispersibility in the monomer constituting the component (A) can be improved. Since it is easy to disperse if it is a powder form, it is especially preferable.

The mixing method in the step (i) is not particularly limited as long as the monomer constituting the component (A), the component (B) and the acid (D) are uniformly mixed. As the step (i), first, the monomer constituting the component (A) and the acid (D) are mixed in the molten state while the monomer constituting the component (A) is heated and stirred, and then the component (B) is mixed. It is preferable to do. By performing mixing in this way, the dispersibility of the component (B) is further improved.

The heating temperature in step (i) needs to be a temperature at which the monomer constituting component (A) melts, that is, a temperature equal to or higher than the melting point of the monomer constituting component (A). For example, when ε-caprolactam is used as the monomer constituting the polyamide resin, it is preferable to melt at a heating temperature of 69 ° C. or higher. Further, when an equimolar salt of adipic acid / hexamethylenediamine is used, it is preferable to melt at a heating temperature of 202 ° C. or higher. Further, regarding the stirring conditions in step (i), the shape of the stirring blade, the number of rotations, and the like are not particularly limited.

As a device for performing the mixing used in step (i), a known mixing device can be used. As such a mixing apparatus, a stirrer such as a propeller mixer, a turbine mixer, or a homomixer can be used. Of these, it is preferable to use a homomixer in terms of handling.

Process (ii) will be described.

Step (ii) is a step of melt polymerizing the mixture obtained in step (i). The conditions for melt polymerization are not particularly limited, but from the viewpoint of improving the polymerization efficiency, the polymerization temperature is preferably 240 to 280 ° C. and the polymerization time is preferably 0.5 to 3 hours.

In the present invention, after the step (ii), a step (iii) of adding a coupling agent (C) and melt-kneading (that is, a melt-kneading step) may be included. By mixing the component (C) in the step (iii), the affinity or adhesion with the component (A) and the component (B) can be improved. In addition, the component (C) suppresses the interface breakage between the component (A) and the component (B), and the impact resistance is improved. In particular, since (B) has a large amount of Si—OH on its surface, the effect of improving impact resistance is very large compared to other inorganic fillers.

When component (C) is added in step (iii) to the polymer comprising component (A), component (B) and component (D) obtained in step (ii), it is not necessary to increase the pressure in the polymerization apparatus. Therefore, it can be handled under atmospheric pressure. Also, other additives can be used in combination during melt-kneading.

When component (C) is added in step (i) or step (iii), the compounding amount of component (C) is 0.05 to 100 parts by mass with respect to 100 parts by mass in total of component (A) and component (B). The amount is preferably 5 parts by mass, more preferably 0.5 to 3 parts by mass. If the amount of component (C) is less than 0.05 parts by mass, the effect of improving the interaction between component (A) and component (B) will be insufficient, and the impact resistance may not be improved. On the other hand, when the amount exceeds 5 parts by mass, the thickening of the component (A) becomes remarkable and the productivity is lowered, which may not be preferable.

According to the production method of the present invention, from the viewpoint of good dispersibility, as shown in FIG. 1, the component (B) in the component (A) is monodispersed fibrous crystals or monodispersed fibers. It is possible to obtain a polyamide resin composition dispersed in a mixture in a state where aggregated crystals are aggregated and the following (I) and (II) are satisfied at the same time.
(I) The fiber length of one monodispersed fibrous crystal is 0.01 to 40 μm, preferably 0.1 to 20 μm. The maximum outer dimension of the aggregate obtained by agglomerating monodispersed fibrous crystals is 0.01 to 40 μm, preferably 0.1 to 20 μm.
(II) The shortest distance between monodispersed fibrous crystals, the shortest distance between aggregates of monodispersed fibrous crystals, and one monodispersed fibrous crystal and monodispersed fibrous crystals The shortest distance between the agglomerated aggregates is 1 to 100 nm, preferably 10 to 50 nm.

In addition, when the component (B) is sufficiently dispersed in the component (A) in the step (i), there is an advantage that it can be easily polymerized by a normal polyamide resin polymerization method (melt polymerization). .

In the above production method, when a conventional filler is used, there is a problem that the melt viscosity of the polymer increases because dispersion occurs in the step (ii). For this reason, the amount of filler added cannot be increased, and the reinforcing effect cannot be sufficiently exhibited.

However, in the present invention, since a specific fibrous clay mineral is used, an increase in melt viscosity during step (ii) can be suppressed, and 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 strength improving effect can be sufficiently exhibited.

In the resin composition of the present invention, as long as the characteristics are not significantly impaired, a heat stabilizer, an antioxidant, a pigment, an anti-coloring agent, a weathering agent, a flame retardant, a plasticizer, a crystal nucleating agent, You may add additives, such as a mold release stabilizer.

In the resin composition of the present invention, other polymers can be blended as required as long as the characteristics are not significantly impaired. 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 desired molded product can be produced by subjecting the resin composition obtained in the present invention to a normal molding method. For example, a molded product can be obtained by using a hot melt molding method such as injection molding, extrusion molding, blow molding, or sintering molding. Moreover, it can also be set as a thin film by melt | dissolving in an organic-solvent solution and attaching | subjecting to a casting method.

The resin composition of the present invention has a low density and excellent mechanical properties as compared with a polyamide resin reinforced with conventional fibers. Therefore, it can be used for automobile parts, electrical parts, household products, etc., and can be used as parts used for parts used around automobile transmissions and engines. Specifically, the base plate used for pedestals such as shift levers and gearboxes around the transmission of an automobile, and the cylinder head cover, engine mount, air intake manifold, throttle body, air intake pipe, radiator tank, radiator support around the engine , Water pump renlet, water pump outlet, thermostat housing, cooling fan, fan shroud, oil pan, oil filter housing, oil filter cap, oil level gauge, timing belt cover, engine cover, etc.

Hereinafter, the present invention will be specifically described by way of examples. However, the present invention is not limited to these examples.

The raw materials used in Examples and Comparative Examples are shown.
1. Raw material (1) Monomer component A-1 constituting the polyamide resin: ε-caprolactam (manufactured by Ube Industries, Ltd .; melting point Tm: 69 ° C.)
A-2: Adipic acid / hexamethylenediamine equimolar salt (melting point Tm: 202 ° C.)
(2) Fibrous clay mineral B-1: Sepiolite (trade name “PANGEL HV” manufactured by TOLSA) 12% by mass
B-2: (B-1) was vacuum-dried at 80 ° C. for 4 hours, and the thermogravimetric reduction rate was adjusted to obtain (B-2). The thermal weight loss rate of (B-2) was 2% by mass.
B-3: (B-1) was vacuum-dried at 80 ° C. for 48 hours, and the thermal weight reduction rate was adjusted to obtain (B-3). The thermal weight loss rate of (B-3) was 0.1% by mass.
B-4: Palygorskite (made by Showa KDE, trade name “POLEISY”) thermal weight loss rate 6 mass%
(3) Coupling agent C-1: 3-glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name “KBM-403”)
C-2: 3-Ureidopropyltriethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name “KBE-585”)
C-3: 3-isocyanatopropyltriethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name “KBE-9007”)
C-4: 3-aminopropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name “KBM-903”)
(4) Acid D-1: Phosphorous acid (manufactured by Nacalai Tesque)
D-2: Phosphoric acid (Nacalai Tesque)
(5) Reinforcement material E: Synthetic fluorine mica (trade name “ME-100” manufactured by Coop Chemical Co., Ltd.)
F: Glass fiber (made by Owens Corning, trade name “MAFT692”)
G: Talc (Nippon Talc Co., Ltd., trade name “K-1”)
The evaluation methods used in the examples and comparative examples are shown below. Note that (3) to (6) were evaluated using test pieces injection-molded at a cylinder temperature of 270 ° C. and a mold temperature of 80 ° C.
2. Test Method (1) The fiber length of one monodispersed fibrous crystal and the maximum outer dimension (μm) of the aggregate in which the monodispersed fibrous crystals are aggregated
The molded product obtained by injection molding was cut using an ultramicrotome (manufactured by LEICA, trade name “EMUC6”) along a plane parallel to the flow direction, and the fibrous clay mineral on the cut surface was monodispersed. The aggregates of the fibrous crystals or the aggregates of the monodispersed fibrous crystals were observed with a transmission electron microscope (trade name “LEM-1230” manufactured by JEOL) at a magnification of 800 times. The observed fiber length of the monodispersed fibrous crystals of the fibrous clay mineral and all the maximum outer dimensions of the aggregates of the aggregated monodispersed fibrous crystals were measured. The largest number was adopted among them.

(2) The shortest distance between monodispersed fibrous crystals, the shortest distance between aggregates of monodispersed fibrous crystals, and one monodispersed fibrous crystal and monodispersed fibrous crystals Minimum distance between aggregated aggregates (nm)
The molded product obtained by injection molding was cut using an ultramicrotome (manufactured by LEICA, trade name “EMUC6”) along a plane parallel to the flow direction, and the fibrous clay mineral on the cut surface was monodispersed. The aggregates of fibrous crystals or monodispersed fibrous crystals were observed with a transmission electron microscope (manufactured by JEOL, trade name “LEM-1230”) at a magnification of 100,000 times. The shortest distance between monodispersed fibrous crystals, the shortest distance between aggregates of monodispersed fibrous crystals, and the aggregation of monodispersed one and monodispersed fibrous crystals The shortest distance between objects (adjacent ones closest to each other) was measured, and an average value of arbitrary 500 pieces of data was adopted.

(3) Density A 10 mm square piece was cut out from a test piece having a length of 100 mm, a width of 10 mm, and a thickness of 4 mm obtained by injection molding, and measured according to ISO 1183.
(4) Bending strength (MPa)
The bending strength (MPa) 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 a pressure of 150 MPa or more are assumed to be practically usable.
(5) Flexural modulus (GPa)
The flexural 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 with 3.5 GPa or more are assumed to be practically usable.
(6) Charpy impact strength (kJ / m ² )
Charpy impact strength (kJ / m ² ) 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 ISO 179-1. In the present invention, those having 2.7 kJ / m ² or more are assumed to be practically usable.

Furthermore, in the resin composition using the component (C), it is preferably 3.3kJ / ^{m 2} or more, more preferably 4.0 kJ / ^{m 2} or more.

(7) Rotational viscosity (Pa · s)
The rotational viscosity at 80 ° C. and 0.3 rpm was measured using a B-type viscometer (manufactured by Toki Sangyo Co., Ltd.). In the measurement, the spindle No. 1 was used.
(8) Thermal weight loss rate (mass%)
5 mg of a measurement sample was placed on a sample stage, heated from 20 ° C. to 500 ° C. at a temperature rising rate of 20 ° C./min in a nitrogen atmosphere, and the mass after heating was measured. The thermal weight reduction rate was calculated by the following formula.
(Thermal weight loss rate) = 100− (sample mass after heating) / (sample mass before heating) × 100
(9) Content of fibrous clay mineral (B) (% by mass)
The mass of the obtained polyamide resin composition was measured. Subsequently, this polyamide resin composition was heated at 500 degreeC for 3 hours, and the residue mass after a heating was measured. The content rate of fibrous clay mineral (B) was computed with the following formula | equation.
[Content of fibrous clay mineral (B)] = (residue mass) / (mass of polyamide resin composition before heating) × 100
Example 1
Put 10 kg of ε-caprolactam (A-1), 1.14 kg of sepiolite (B-1), and 20 g of phosphorous acid (D-1) in the same container. Using a mixer (manufactured by Primix Co., Ltd., trade name “TK homomixer MARKII20”, stirring blade diameter 44 mm, clearance 1 mm), the mixture was stirred and mixed at a rotational speed of 4000 rpm to prepare a mixture. The shear rate at this time was 9210 sec ⁻¹ .

So far, it is process (i). The rotational viscosity increased with time, and the rotational viscosity at the start of stirring was 5 Pa · s, but the rotational viscosity after 2 hours was 55 Pa · s. Next, the mixture obtained in the above step (i) was put into an autoclave to be polymerized in the next step (ii) and polymerized for 1 hour while stirring at an internal temperature of 260 ° C.

After completion of the polymerization, the polymer taken in the form of a strand 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.

The dried pellets are 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.) to produce a test piece (molded product). did. Table 1 shows the composition of the obtained molded product. In addition, stirring conditions, rotational viscosity, fiber length of one monodispersed fibrous crystal, and the maximum outer dimension (fiber length or maximum outer dimension) of the aggregate in which monodispersed fibrous crystals are aggregated, monodispersed fibers Shortest distance between crystal-like crystals, shortest distance between aggregates of monodispersed fibrous crystals, and between a single monodispersed fibrous crystal and aggregates of monodispersed fibrous crystals Table 2 shows the shortest distance (shortest distance), density, bending strength, bending elastic modulus, and Charpy impact strength.

(Example 2)
Put 10 kg of ε-caprolactam (A-1) and 20 g of phosphorous acid (D-1) in the same container and stir at a rotation speed of 4000 rpm using a homomixer until it becomes a homogeneous solution while heating at 80 ° C. Thereafter, 1.14 kg of sepiolite (B-1) was added and the mixture was stirred and mixed in the same manner until a uniform solution was obtained to obtain a polyamide resin composition in the same manner as in Example 1, The polyamide resin composition was injection molded to obtain a molded product. Evaluation was performed about the obtained molded article. The composition is shown in Table 1, and the evaluation results are shown in Table 2.
(Examples 3 to 12)
As shown in Table 1, the type of fibrous clay mineral and the blending amount of fibrous clay mineral were changed, and the stirring conditions in step (i) were changed, and a polyamide resin composition was prepared in the same manner as in Example 2. The polyamide resin composition was injection molded to obtain a molded product. Evaluation was performed about the obtained molded article. The composition is shown in Table 1, and the evaluation results are shown in Table 2.
(Example 13)
A polyamide resin composition was obtained in the same manner as in Example 2 except that phosphoric acid (D-2) was used instead of phosphorous acid (D-1), and the molded article was obtained by injection molding the polyamide resin composition. Obtained. Evaluation was performed about the obtained molded article. The composition is shown in Table 1, and the evaluation results are shown in Table 2.
(Comparative Example 1)
A polyamide resin composition was obtained in the same manner as in Example 2 except that the fibrous clay mineral was not used, and the polyamide resin composition was injection molded to obtain a molded product. Evaluation was performed about the obtained molded article. The composition is shown in Table 1, and the evaluation results are shown in Table 2.
(Comparative Examples 2 to 6)
As shown in Table 1, the type of the reinforcing material and the blending amount of the reinforcing material were changed. Further, as shown in Table 2, the stirring conditions in step (ii) were changed, and the polyamide resin was changed in the same manner as in Example 2. A composition was obtained, and the polyamide resin composition was injection molded to obtain a molded product. Evaluation was performed about the obtained molded article. The composition is shown in Table 1, and the evaluation results are shown in Table 2.
(Comparative Example 7)
10 kg of ε-caprolactam (A) and 1.14 kg of sepiolite (B-1) were put in the same reaction vessel, pre-stirred and mixed, and then the mixture in the vessel was stirred and mixed while flowing nitrogen gas into the vessel. Next, while stirring, the reaction vessel was heated to 220 ° C. and stirred for 1 hour. Thereafter, the reaction vessel was heated to 260 ° C. to polymerize the polyamide resin. The obtained polyamide resin composition was injection molded in the same manner as in Example 2 to obtain a molded product. Evaluation was performed about the obtained molded article. The composition is shown in Table 1, and the evaluation results are shown in Table 2.

As is clear from Tables 1 and 2, the polyamide resin compositions of Examples 1 to 13 were superior in both bending strength and flexural modulus as compared with Comparative Example 1 in which no fibrous clay mineral was blended.

In particular, the polyamide resin compositions of Examples 1 to 5 and 10 to 13 were excellent in the balance of flexural strength, flexural modulus, and impact resistance because the content of the polyamide resin and the fibrous clay mineral was in a particularly preferred range. It became a thing.

In the polyamide resin compositions of Example 6 and Example 8, the composition of the fibrous clay mineral was within the specified range and was in the vicinity of the upper limit value or was the upper limit value, so the rotational viscosity was high and the dispersibility was high. Declined. Therefore, the fiber length or the maximum outer dimension of the aggregate is large. However, since the amount of the fibrous clay mineral was sufficiently large, the bending strength and the bending elastic modulus were more excellent.

The polyamide resin composition of Comparative Example 1 was inferior in both bending strength and flexural modulus because no fibrous clay mineral was blended.

Since the polyamide resin composition of Comparative Example 2 had an excessively low shear rate, the fiber length or maximum outer diameter and the shortest distance of the fibrous clay mineral were excessive, and therefore the fibrous clay mineral was not sufficiently dispersed. As a result, the bending strength was inferior.

The polyamide resin composition of Comparative Example 3 had no reinforcing effect because the blending amount of the fibrous clay mineral was too small, and both the bending strength and the flexural modulus were inferior.

In Comparative Example 4, the rotational viscosity of the mixture increased because the amount of fibrous clay mineral was excessive. Therefore, stirring at the time of polymerization is difficult, subsequent polymerization becomes insufficient, and a polyamide resin composition cannot be obtained.

In Comparative Example 5, since a layered clay mineral that is not a fibrous clay mineral was used, the polyamide resin composition obtained in step (ii) had an excessively high melt viscosity and could not be dispensed from the autoclave.

In Comparative Example 6, since glass fibers were used instead of fibrous clay minerals, the bending strength and the bending elastic modulus were inferior to those of the resin compositions having the same density obtained in the present invention.

In Comparative Example 7, a polyamide resin composition was obtained without blending acid. Therefore, the fiber length of one monodispersed fibrous crystal of the used fibrous clay mineral and the maximum outer dimension of the aggregate in which the monodispersed fibrous crystals are aggregated are excessive, and either the bending strength or the flexural modulus is exceeded. The result was inferior.
(Example 14)
Put 10 kg of ε-caprolactam (A-1) and 20 g of phosphorous acid (D-1) in the same container, and heat at 80 ° C. until homogenous solution is obtained (product name “T” K. Homomixer MARK II 20 ”, stirring blade diameter 44 mm, clearance 1 mm), stirring and mixing at a rotation speed of 4000 rpm, and then adding 1.14 kg of sepiolite (B-1) with stirring to obtain a uniform mixture Was made. The shear rate at this time was 9210 sec ⁻¹ . So far, it is process (i). The rotational viscosity increased with time, and the rotational viscosity at the start of stirring was 5 Pa · s, but the rotational viscosity after 422 hours was 55 Pa · s. Next, the mixture obtained in the above step (i) was put into an autoclave to be polymerized in the next step (ii) and polymerized for 1 hour while stirring at an internal temperature of 260 ° C.

Using a twin-screw extruder (trade name “TEM37BS type” manufactured by Toshiba Machine Co., Ltd.), dry-blend 3 kg of dried pellets and 30 g of coupling agent (C-1), and top feed from the root supply port of the extruder. Extrusion was carried out while venting under the conditions of a barrel temperature of 250 to 270 ° C., a screw speed of 200 rpm, and a discharge of 15 kg / h. The molten resin discharged from the tip of the extruder was drawn into a strand shape, passed through a vat filled with cooling water, cooled and solidified, and then cut into a pellet shape 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 3 shows the composition of the obtained molded product. In addition, stirring conditions, rotational viscosity, fiber length of one monodispersed fibrous crystal, and the maximum outer dimension (fiber length or maximum outer dimension) of the aggregate in which monodispersed fibrous crystals are aggregated, monodispersed fibers Shortest distance between crystal-like crystals, shortest distance between aggregates of monodispersed fibrous crystals, and between a single monodispersed fibrous crystal and aggregates of monodispersed fibrous crystals Table 4 shows the shortest distance (shortest distance), density, bending strength, bending elastic modulus, and Charpy impact strength.

(Examples 15 to 29)
As shown in Table 3, the type and blending amount of the fibrous clay mineral, the type and blending amount of the coupling agent were changed, and the stirring conditions were changed as shown in Table 4. A resin composition was obtained, and the polyamide resin composition was injection molded to obtain a molded product. Evaluation was performed about the obtained molded article. The composition is shown in Table 3, and the evaluation results are shown in Table 4.
(Example 30)
Put 10 kg of ε-caprolactam (A-1) and 20 g of phosphorous acid (D-1) in the same container, and heat at 80 ° C. until homogenous solution is obtained (product name “T” K. Homomixer MARK II 20 ") and stirring and mixing at a rotational speed of 4000 rpm, and then adding 1.14 kg of sepiolite (B-1) and 111 g of coupling agent (C-1) while stirring. A mixture was made. So far, it is process (ii). The rotational viscosity increased with time, and the rotational viscosity at the start of stirring was 5 Pa · s, but the rotational viscosity after 2 hours was 65 Pa · s. Next, in order to subject the mixture obtained in the step (i) to polymerization in the step (ii), the mixture was put into an autoclave and polymerized for 1 hour while stirring at an internal temperature of 260 ° C.

After completion of the polymerization, the autoclave was pressurized with nitrogen so that the inside of the autoclave became 1 MPa, and the polymer taken in a strand shape from the bottom exhaust 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.

The dried pellets were injection molded in the same manner as in Example 14 to prepare test pieces. Evaluation was performed about the obtained molded article. The composition is shown in Table 3, and the evaluation results are shown in Table 4.
(Example 31)
Homomixer until 10 kg of adipic acid / hexamethylenediamine equimolar salt (A-2) and 20 g of phosphorous acid (D-1) are placed in the same container and heated to 205 ° C. in a nitrogen atmosphere until a homogeneous solution is obtained. (Product name “TK homomixer MARKII20” manufactured by Primix Co., Ltd.) was stirred and mixed at a rotational speed of 4000 rpm, and then 1.14 kg of sepiolite (B-1) was added while stirring. A mixture was made. So far, it is process (i). The rotational viscosity after stirring for 0.5 hours was 35 Pa · s. Next, the mixture obtained in the step (i) was put into an autoclave in order to be subjected to polymerization in the step (ii). While stirring at an internal temperature of 230 ° C., heating is performed 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 and 2 hours. Polymerization was performed.

After completion of the polymerization, the polymer taken on the strand from the low defecation 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.

Thereafter, test pieces were prepared in the same manner as in Example 14 except that the barrel temperature of the twin screw extruder was 270 to 290 ° C. and the cylinder temperature of the injection molding machine was 270 ° C. Evaluation was performed about the obtained molded article. The composition is shown in Table 3, and the evaluation results are shown in Table 4.
(Examples 32 to 37)
As shown in Table 3, the type and amount of the reinforcing material, the amount of acid, the type and amount of the coupling agent were changed, and the stirring conditions were changed as shown in Table 4. Thus, a polyamide resin composition was obtained, and the polyamide resin composition was injection molded to obtain a molded product. Evaluation was performed about the obtained molded article. The composition is shown in Table 3, and the evaluation results are shown in Table 4.
(Comparative Example 8)
A polyamide resin composition was obtained in the same manner as in Example 14 except that the fibrous clay mineral was not used, and the polyamide resin composition was injection molded to obtain a molded product. Evaluation was performed about the obtained molded article. The composition is shown in Table 3, and the evaluation results are shown in Table 4.
(Comparative Examples 9-12)
As shown in Table 3, the type and amount of the reinforcing material, the amount of acid, the type and amount of the coupling agent were changed, and the stirring conditions were changed as shown in Table 4. Thus, a polyamide resin composition was obtained, and the polyamide resin composition was injection molded to obtain a molded product. Evaluation was performed about the obtained molded article. The composition is shown in Table 3, and the evaluation results are shown in Table 4.
(Comparative Examples 13 to 15)
A polyamide resin composition was obtained in the same manner as in Example 14 except that glass fiber or talc was used as the reinforcing material, and the polyamide resin composition was injection molded to obtain a molded product. Evaluation was performed about the obtained molded article. The composition is shown in Table 3, and the evaluation results are shown in Table 4.
(Comparative Example 16)
Sepiolite (B-1) 1.14 kg and 1.14 kg of water were used at a rotational speed of 4000 rpm while maintaining the liquid temperature at 20 ° C. using a homomixer (trade name “TK homomixer MARKII20” manufactured by PRIMIX Corporation). A water suspension was prepared by stirring and mixing. Next, 111 g of coupling agent (C-1) was added to this aqueous suspension, and stirring was continued. After stirring for 2 hours, 10 kg of ε-caprolactam (A-1) was added, and stirring was continued to prepare a uniform mixture. So far, it is process (ii). The rotational viscosity increased with time, and the rotational viscosity at the start of stirring was 50 Pa · s, but the rotational viscosity after 30 minutes was 850 Pa · s. Subsequently, in order to subject the mixture obtained in the step (i) to polymerization in the step (ii), the mixture was put into an autoclave, stirred while removing water in the system at an internal temperature of 260 ° C., and polymerized for 1 hour. . After the polymer was dispensed, various evaluations were performed in the same manner as in Example 14. The composition is shown in Table 3, and the evaluation results are shown in Table 4.
(Comparative Example 17)
Various evaluations were performed in the same manner as Comparative Example 19 except that 20 g of phosphorous acid (D-1) was added when 10 kg of ε-caprolactam (A-1) was added. The composition is shown in Table 3, and the evaluation results are shown in Table 4.
(Comparative Example 18)
Various evaluations were performed in the same manner as in Example 1 except that the number of rotations during stirring by the homomixer was 12000 rpm. The composition is shown in Table 3, and the evaluation results are shown in Table 4.

As is clear from Tables 3 and 4, the polyamide resin compositions of Examples 14 to 34 were superior in both bending strength and flexural modulus compared to Comparative Example 8 in which no fibrous clay mineral was blended.

In particular, the polyamide resin compositions of Example 20 and Example 22 had a high rotational viscosity and reduced dispersibility because the composition of the fibrous clay mineral was within the specified range and was in the vicinity of the upper limit value or the upper limit value. However, the fiber length or the maximum outer size of the agglomerates was large. However, since the amount of the fibrous clay mineral was sufficiently large, the bending strength and the bending elastic modulus were more excellent.

The polyamide resin composition of Example 32 had a room for improvement in impact resistance because the coupling agent content was excessive.

The polyamide resin composition of Example 33 was superior in both bending strength and flexural modulus as compared with Comparative Example 1 in which no fibrous clay mineral was blended. However, since the content of the coupling agent was less than the preferred range of the present invention, no improvement in impact resistance was observed.

The polyamide resin composition of Comparative Example 8 was inferior in bending strength, bending elastic modulus, and bending elastic modulus because no fibrous clay mineral was blended.

In Comparative Example 9, since the value of the shear rate was too small, the fiber length or the maximum outer diameter and the shortest distance of the fibrous clay mineral were excessive, the dispersion of the fibrous clay mineral was insufficient, and the impact resistance was The result was high but inferior in bending strength.

The polyamide resin composition of Comparative Example 10 had no reinforcing effect because the blending amount of the fibrous clay mineral was too small, and the bending strength, bending elastic modulus, and impact resistance were all inferior.

In the polyamide resin composition of Comparative Example 11, since the amount of the fibrous clay mineral was excessive, stirring during the polymerization was difficult, the subsequent polymerization was insufficient, and a polyamide resin composition could not be obtained. .

In Comparative Example 12, since the polyamide resin composition was obtained without blending the acid, the fiber length of one monodispersed fibrous crystal of the used fibrous clay mineral and the monodispersed fibrous crystals aggregated. The maximum outer dimension of the agglomerated material was excessive, resulting in poor bending strength, flexural modulus, and impact resistance.

In Comparative Example 13, since glass fiber was used instead of fibrous clay mineral, the bending strength and the bending elastic modulus were inferior to those of the resin composition having the same density obtained in the present invention.

In Comparative Examples 14 and 15, since talc was used instead of fibrous clay mineral, the bending properties and impact resistance were inferior to the resin composition obtained in the present invention.

In Comparative Examples 16 and 17, since a polyamide resin composition was obtained by adding ε-caprolactam to an aqueous dispersion obtained by mixing sepiolite and water, the rotational viscosity was high and stirring during polymerization was not performed. It was enough. Therefore, the shortest distance between the fibrous clay minerals is too short, and the flexural modulus and impact resistance are poor.

In Comparative Example 18, since the shear rate by the homomixer exceeded the upper limit, the dispersion of the fibrous clay mineral progressed too much. As a result, the shortest distance between the fibrous clay minerals was too short and the bending properties were poor.

The polyamide resin composition of the present invention is useful because it has a low density, excellent mechanical properties, and a simplified manufacturing process as compared with a polyamide resin reinforced with conventional fibers.

Claims

A polyamide resin composition comprising 70 to 99.5 parts by mass of a polyamide resin (A) and 0.5 to 30 parts by mass of a fibrous clay mineral (B), the fibrous clay mineral in the polyamide resin (A) A polyamide resin composition, wherein (B) monodispersed fibrous crystals and / or aggregates of monodispersed fibrous crystals are dispersed in the following states (I) and (II): object.
(I) The fiber length of one monodispersed fibrous crystal is 0.01 to 40 μm, and the maximum outer size of the aggregate obtained by agglomerating monodispersed fibrous crystals is 0.01 to 40 μm.
(II) The shortest distance between monodispersed fibrous crystals, the shortest distance between aggregates of monodispersed fibrous crystals, and one monodispersed fibrous crystal and monodispersed fibrous crystals The shortest distance between the aggregated aggregates is 1 to 100 nm.
The coupling agent (C) is contained in an amount of 0.05 to 5 parts by mass with respect to a total of 100 parts by mass of the polyamide resin (A) and the fibrous clay mineral (B). Polyamide resin composition.
The polyamide resin composition according to claim 1 or 2, wherein the fibrous clay mineral (B) is sepiolite and / or palygorskite.
The polyamide resin composition according to claim 2 or 3, wherein the coupling agent (C) is a silane coupling agent containing a reactive group selected from an epoxy group, a ureido group and an isocyanate group.
After melting 70 to 99.5 parts by mass of the monomer constituting the polyamide resin (A) and 0.01 to 5 parts by mass of the acid (D) at a temperature T equal to or higher than the melting point of the monomer, the fibrous clay mineral (B A step (i) of mixing 0.5 to 30 parts by mass at a shear rate of 1000 to 20000 sec −1 and a step (ii) of melt-polymerizing the mixture obtained in the step (i). To obtain a polyamide resin composition in which monodispersed fibrous crystals of clay mineral (B) and / or aggregates of aggregated monodispersed fibrous crystals are dispersed in the following states (I) and (II): A process for producing a polyamide resin composition characterized by the above.
(I) The fiber length of one monodispersed fibrous crystal is 0.01 to 40 μm, and the maximum outer diameter of the aggregate obtained by agglomerating monodispersed fibrous crystals is 0.01 to 40 μm.
(II) The shortest distance between monodispersed fibrous crystals, the shortest distance between aggregates of monodispersed fibrous crystals, and one monodispersed fibrous crystal and monodispersed fibrous crystals The shortest distance between the aggregated aggregates is 1 to 100 nm.
In step (i), 0.05 to 5 parts by mass of the coupling agent (C) is mixed with 100 parts by mass of the monomer constituting the polyamide resin (A) and the fibrous clay mineral (B). The manufacturing method of the polyamide resin composition of Claim 5 characterized by these.
After step (ii), 0.05 to 5 parts by mass of the coupling agent (C) is added to 100 parts by mass of the monomer constituting the polyamide resin (A) and the fibrous clay mineral (B). The method for producing a polyamide resin composition according to claim 5, further comprising a step (iii) of melt kneading.
In the step (i), the mixing is carried out so that the rotational viscosity measured by a B-type viscometer at a temperature T after a mixing time of 0.5 hours or more is 1 to 500 Pa · s. The manufacturing method of the polyamide resin composition in any one of.