JP2009007483A - Glass fiber reinforced polyamide resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reinforced polyamide resin composition having improved mechanical properties, especially being improved in the occurrence of shrink marks; by using a flat glass fiber with a flat cross section and a swelling layered silicate in combination. <P>SOLUTION: The swelling layered silicate (A) has an aliphatic primary amine of 0.5-30 parts by mass, based on the swelling layered silicate of 100 parts by mass, intercalated into an interlayer. The flat glass fiber (B) has the flat cross section in which the minor axis is 3-10 μm, and the major axis/the minor axis rate is 1.5-10. The reinforced polyamide resin composition is formed by mixing the swelling layered silicate represented by (A) of 1-50 parts by mass with the flat glass fiber with the flat cross section represented by (B) of 5-150 parts by mass, based on a polyamide resin of 100 parts by mass. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a reinforced polyamide resin composition, and further relates to a reinforced polyamide resin composition in which flat glass fibers having a flat cross section and a swellable layered silicate are used in combination.

Polyamide resins are widely used particularly as injection molding materials for parts such as automobiles and home appliances because the molded products have excellent mechanical properties. When imparting mechanical properties to a polyamide molded product, a polyamide resin composition reinforced with a fibrous reinforcing material is usually used, and a polyamide resin composition containing a specific amount of glass fiber as the fibrous reinforcing material Has been proposed. However, the polyamide resin composition has a problem that when it is molded by injection molding, the warp of the molded product is large and the dimensional stability is low.
In Patent Document 1 below, as a method for producing a polyamide resin composition that reduces warping and twisting of a molded product and causes little reduction in strength, a glass fiber having a flat cross section and a glass fiber having a normal cross section are mixed. A polyamide resin composition is described.
However, a polyamide resin composition obtained by mixing a glass fiber having a flat cross section with a glass fiber having a normal cross section has a problem that shrinkage in the thickness direction of the molded product is large and sink marks are likely to occur.
JP 10-2119026

  An object of the present invention is to provide a reinforced polyamide resin composition in which mechanical properties, particularly sink marks, of a reinforced polyamide resin composition are improved by the combined use of flat glass fibers having a flat cross section and a swellable layered silicate.

As a result of intensive studies in order to solve such problems, the present inventors have found that a specific resin composition solves the problems, and have completed the present invention.
That is, the gist of the present invention is as follows.
A swellable layered silicate (A) in which 0.5 to 30 parts by mass of an aliphatic primary amine is inserted between layers with respect to 100 parts by mass of a swellable layered silicate, and a minor axis of 3 to 10 μm and a major axis / A polyamide resin composition obtained by mixing a flat glass fiber (B) having a flat cross-section with a minor axis ratio of 1.5 to 10, wherein the swelling shown in (A) with respect to 100 parts by mass of the polyamide resin It is a reinforced polyamide resin composition formed by mixing 1 to 50 parts by mass of a layered silicate and 5 to 150 parts by mass of flat glass fibers having a flat cross section represented by (B).

  ADVANTAGE OF THE INVENTION According to this invention, the reinforced polyamide resin composition by which the mechanical property of the reinforced polyamide resin composition by the combined use of the flat glass fiber which has a flat cross section, and a swellable layered silicate, especially a sink mark was improved can be obtained.

Hereinafter, the present invention will be described in detail.
The swellable lamellar silicate used in the present invention has a structure composed of a negatively charged crystal layer mainly composed of silicate and a cation having an ion exchange ability interposed between the layers. The calculated cation exchange capacity is desirably 50 meq / 100 g or more. When the cation exchange capacity is less than 50 meq / 100 g, the swelling ability is low, so that the polyamide composite material remains substantially in an uncleavage state, and no performance improvement is observed. In the present invention, the upper limit of the value of the cation exchange capacity is not particularly limited, and an appropriate one may be selected from swellable layered silicates that can be actually prepared.
Such swellable layered silicates may be naturally occurring, artificially synthesized or modified, such as smectites (montmorillonite, beidellite, hectorite, soconite, etc.), vermiculites (vermiculite, etc.), mica Family (fluorine mica, muscovite, paragonite, phlogopite, lepidrite, etc.), brittle mica family (margarite, clintonite, anandite, etc.), chlorite family (donbasite, sudoite, kukeite, clinochlore, chamonite, nimite, etc.) In the present invention, Na-type or Li-type swellable fluorine mica and montmorillonite are particularly preferably used.

The swellable fluorine mica preferably used in the present invention generally has a structural formula represented by the following formula.
Mα (Mg _X Li _β ) Si ₄ O _Y F _Z
(In the formula, M represents an ion-exchangeable cation, specifically sodium or lithium. Α, β, X, Y, and Z each represents a coefficient, and 0 ≦ α ≦ 1.0. 0 ≦ β ≦ 1.0, 2.5 ≦ X ≦ 4, 10 ≦ Y ≦ 15, 1.0 ≦ Z ≦ 2.0)
As a method for producing such a swellable fluorine mica, for example, silicon oxide, magnesium oxide and various fluorides are mixed, and the mixture is completely melted in a temperature range of 1400 to 1500 ° C. in an electric furnace or a gas furnace. A melting method in which a crystal of swellable fluorinated mica grows in the reaction vessel during the cooling process.

On the other hand, there is also a method of using talc [Mg ₃ Si ₄ O ₁₀ (OH) ₂ ] as a starting material and intercalating alkali metal ions to impart swellability to obtain a swellable fluorine mica (Japanese Patent Laid-Open No. Hei. No. 2-149415). In this method, swellable fluoromica can be obtained by heat-treating talc and alkali silicofluoride mixed at a predetermined blending ratio in a magnetic crucible at a temperature of 700 to 1200 ° C. for a short time.

At this time, the amount of alkali silicofluoride mixed with talc is preferably in the range of 10 to 35% by mass of the entire mixture. If it is out of this range, the yield of swellable fluorinated mica tends to decrease.
The montmorillonite used in the present invention is represented by the following formula, and can be obtained by refining a naturally produced product using a water treatment or the like.
MaSi (Al _2-a Mg) O ₁₀ (OH) ₂ .nH ₂ O
(In the formula, M represents a cation such as sodium, and 0.25 ≦ a ≦ 0.7. The number of water molecules bonded to the interlayer ion-exchangeable cation depends on conditions such as cation species and humidity. (It is expressed by nH2O in the formula.)
In addition, montmorillonite is known to have isomorphic ion substitution products such as magnesia montmorillonite, iron montmorillonite, iron magnesia montmorillonite, and these may be used.

In the present invention, there is no particular limitation on the initial particle size of the above-described swellable layered silicate. Here, the initial particle size is the particle size of the swellable layered silicate as a raw material used in producing the polyamide resin composition used in the present invention, and is different from the size of the silicate layer in the composite material. However, this particle size also has a considerable influence on the physical properties of the obtained polyamide composite material, in particular the rigidity and heat resistance. Therefore, it is desirable to take this point into consideration when selecting the mixing ratio of the above-mentioned swellable layered silicate, and it is preferable to control the particle size by pulverizing with a jet mill or the like as necessary.
Here, when the swellable fluoromica mineral is synthesized by the intercalation method, the initial particle size can be changed by appropriately selecting the particle size of talc as a raw material. This is a preferable method in that the initial particle diameter can be adjusted in a wider range by using in combination with pulverization.

The aliphatic primary amine inserted between the layers of the swellable layered silicate used in the present invention is specifically octylamine, nonylamine, decylamine, undecylamine, dodecylamine, tridecylamine, tetradecylamine, pentadecyl. Examples include amine, stearylamine, oleylamine and the like. By dissolving the halogenated salt or metal salt of these amines in pure water, mixing a predetermined amount of swellable layered silicate into the solution, stirring at room temperature, filtering and drying, A swellable layered silicate having these amine cations inserted between the layers can be obtained. This was baked in air at 600 ° C. to remove organic substances, and then the amount of each amine inserted between the layers was calculated by measuring the mass of the residue.
The aliphatic primary amine is preferably 0.5 to 30 parts by mass with respect to the swellable layered silicate. When the amount is less than 0.5 parts by mass, the effect of improving the tensile strength of the obtained glass-reinforced resin composition is small. When the amount is 30 parts by mass or more, no further reaction between the layers of the swellable layered silicate occurs. When the aliphatic primary amine remaining unreacted is mixed with the polyamide resin, the mechanical properties of the polyamide resin composition are deteriorated, which is not preferable.

  The amount of the swellable layered silicate treated with the aliphatic primary amine is preferably 1 to 50 parts by mass with respect to 100 parts by mass of the polyamide resin in the resin composition. When the blending amount is less than 1 part by mass, the mechanical strength is hardly improved. On the other hand, when the blending amount exceeds 50 parts by mass, the reinforcing efficiency with respect to the tensile strength is lowered, which is not preferable.

  The polyamide resin in the present invention is a polymer having an amide bond in the main chain, the main raw material of which is aminocarboxylic acid, lactam or diamine and dicarboxylic acid (including a pair of salts thereof). Specific examples of the raw material include aminocarboxylic acids such as 6-aminocaproic acid, 11-aminoundecanoic acid, and 12-aminododecanoic acid. 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 such polyamide resin 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), Examples include polyhexamethylene sebamide (nylon 610), polyhexamethylene dodecamide (nylon 612), polyundecamethylene adipamide (nylon 116), and mixtures or copolymers thereof. Of these, nylon 6 and nylon 66 are particularly preferable.

  The glass fiber (B) in the present invention is produced by a known method for producing glass fiber, and is improved in adhesion to the matrix resin and uniform dispersibility by a silane coupling agent, a titanium coupling agent, and a zirconia coupling. The glass fiber strands that have been bundled and bundled by a known sizing agent suitable for a resin containing at least one coupling agent such as an agent, an antistatic agent, and a film forming agent are collected to a certain length. Used in the form of chopped strands cut into pieces. The cross section of the flat glass fiber used in the present invention is preferably a gourd type, eyebrow type, oval type, elliptical type, rectangular shape, or a similar product. The flat fibers having a major axis / minor axis ratio of 1.5 to 10 are used, and those having a major axis / minor axis ratio of 6.0 to 6.0 are more preferable. When the ratio of major axis / minor axis is 1.5 or less, the effect of flattening the cross section is small, and when the ratio is 10 or more, it is difficult to produce the glass fiber itself.

  The manufacturing method of the reinforced polyamide resin composition of the present invention is a swellable lamellar silicate in which 0.5 to 30 parts by mass of an aliphatic primary amine is inserted between layers with respect to 100 parts by weight of the swellable lamellar silicate ( A), flat glass fiber (B) having a flat cross section, and 100 parts by weight of polyamide resin are generally melt-kneaded, but the method is not limited to this.

  Further, the thermoplastic resin composition of the present invention may be mixed with other thermoplastic polymers. In this case as well, it is preferable to mix and alloy using a twin screw extruder equipped with a screw. . In such a resin composition, since the swellable fluoromica mineral is uniformly dispersed in the polyamide resin at the molecular level, mechanical strength and heat resistance are improved as compared with an alloyed product with an unreinforced polyamide resin.

  Examples of the thermoplastic polymer include polybutadiene, butadiene / styrene copolymer, acrylic rubber, ethylene / propylene copolymer, ethylene / propylene / diene copolymer, natural rubber, chlorinated butyl rubber, and chlorinated polyethylene. Elastomers or their acid-modified products such as maleic anhydride, styrene / maleic anhydride copolymer, styrene / phenylmaleimide copolymer, polyethylene, polypropylene, butadiene / acrylonitrile copolymer, polyvinyl chloride, polyethylene terephthalate, polybutylene Terephthalate, polyacetal, polyvinylidene fluoride, polysulfone, polyphenylene sulfide, polyethersulfone, phenoxy resin, polyphenylene ether, polymethyl methacrylate, polyether Tons, polycarbonate, polytetrafluoroethylene, etc. polyarylate and the like. At this time, the thermoplastic polymer is preferably mixed at a ratio of 60 parts by mass or less with respect to 100 parts by mass of the reinforced polyamide resin (A).

In producing the polyamide resin composition of the present invention, as long as its properties are not significantly impaired, a heat stabilizer, an antioxidant, a reinforcing material, a pigment, an anti-coloring agent, a weathering agent, a flame retardant, a plasticizer, a crystal nucleus An agent, a release agent and the like may be added.
Examples of the heat stabilizer and the antioxidant include hindered phenols, phosphorus compounds, hindered amines, sulfur compounds, copper compounds, alkali metal halides, and mixtures thereof.

The polyamide resin composition of the present invention can be formed into a desired molded product by a normal molding method, for example, various molded products by a hot melt molding method such as injection molding, extrusion molding, blow molding, or an organic solvent. A thin film can be formed by casting from a solution.
As the above molded products, pipes, hollow pipes, handles, ink containers, curtain rails, gear parts, bearing retainers, brushes, reels, breaker covers, switches, connectors, automotive exterior parts, automotive interior parts, light covers, Useful for various applications such as intake manifolds, timing belt covers, wheels, engine covers, cylinder head covers, box-formed products, especially audio trays such as CDs and DVDs that require lightweight, housings for mobile phones, It is preferable as a housing (housing) for various devices such as a pager base frame and a housing for a personal computer. In particular, it is useful for a molded product having a thin portion as described above, and particularly useful for a box-shaped product having a portion having a thickness of 1.0 mm or less, particularly a housing for a personal computer or a mobile phone.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist. In addition, the raw material used for the Example and the comparative example and the physical property measuring method are as follows.

1 Raw material (A) Polyamide resin / Polyamide 6 (Unitika A1030BRL relative viscosity 2.6)
Polyamide 66 (A125 relative viscosity 2.8 manufactured by Unitika)
・ Polyamide 11 (BMNOTLD relative viscosity 1.8 manufactured by Arkema)
(B) Swellable layered silicate, swellable synthetic fluorinated mica (ME-100, manufactured by Corp Chemical Chemical)
・ Montmorillonite (Kunipia F manufactured by Kunipia)
(C) Interlayer treatment agent (1) Aliphatic primary amine, octylamine, stearylamine (2) Treatment agent other than aliphatic primary amine, 6-aminocaproic acid (D) Glass fiber, glass fiber A: Long and short Flat glass fiber having an oval cross section with a diameter ratio of 2 (Nittobo CSH3PA870, major axis 20 μm, minor axis 10 μm, with silane surface treatment)
Glass fiber B: flat glass fiber having an oval cross section with a major / minor diameter ratio of 4 (Nittobo CSG3PA820, major axis 28 μm, minor diameter 7 μm, with silane surface treatment)
Glass fiber C: Glass fiber having a circular cross section with a diameter of 10 μm and a length of 3 mm (CS3J-451 manufactured by Nittobo Co., Ltd., with silane surface treatment)

2 Measuring method (1) Tensile breaking strength Measured at 23 ° C. according to ISO527. 180 MPa or higher was accepted. However, as in Example 9, the material using polyamide 11 as the polyamide resin did not improve the tensile strength at break as compared with the case of using polyamide 6 or polyamide 66. This is because of the characteristics of the polyamide, and 120 MPa or more was accepted.
(2) Sink observation When a molded product is observed from the front side in a molded product with two ribs on each side of the molded product in a box shape of 50 × 70 × 20 mm (thickness 1 mm), is the rib part recessed? I observed it.
In the evaluation, ◯: no dent in the rib part, x: dent in the rib part.

Production Examples A1 to A8
1-30 g of halogenated salt of the interlayer treating agent was dissolved in 10 L of pure water, 100 g of swellable layered silicate was mixed into the solution, and the mixture was stirred at 23 ° C. After fully dissolving, it was filtered and dried to obtain a swellable layered silicate having these amine cations inserted between the layers. This was baked in air at 600 ° C. to remove organic substances, and then the amount of each amine inserted between the layers was calculated by measuring the mass of the residue. The results are shown in Table 1.

Example 1
Continuous determination of 5 parts by mass of swellable synthetic fluorinated mica (A1) organically treated with octylamine and 5 parts by mass of flat glass fiber (B) having a flat cross section with respect to 100 parts by mass of polyamide 6 resin. Using a supply device, the resin composition is supplied to the main supply port of the same-direction twin screw extruder (TEM 37BS manufactured by Toshiba Machine), melted and kneaded, and taken into a strand from the die, cooled and solidified through a water tank, and then pelletized. To obtain pellets of the resin composition. The extrusion conditions were a temperature setting of 250 to 270 ° C., a screw rotation speed of 250 rpm, a discharge rate of 35 kg / h, and a resin temperature of the resin composition from the die was 260 ° C. Next, the obtained resin composition pellets were injection-molded using an injection molding machine (EC100 manufactured by Toshiba Machine Co., Ltd.) under conditions of a cylinder temperature of 270 ° C. and a mold temperature of 100 ° C. to produce physical property measurement test pieces, and various evaluation tests Went. The evaluation results are shown in Table 2. As a result, no dent was found in the rib portion and the tensile strength at break was high.

Example 2
A resin composition was obtained in the same manner as in Example 1, except that 45 parts by mass of (A2) was mixed with the organically treated swellable synthetic fluorinated mica and 150 parts by mass of flat glass fiber (A) was added. The evaluation results are shown in Table 2. As a result, no dent was found in the rib portion and the tensile strength at break was high.
Example 3
A resin composition was obtained in the same manner as in Example 1 except that 10 parts by mass of (A3) was added to the organically treated swellable synthetic fluorinated mica and 30 parts by mass of flat glass fiber (B) was added. The evaluation results are shown in Table 2. As a result, no dent was found in the rib portion and the tensile strength at break was high.
Example 4
A resin composition was obtained in the same manner as in Example 1 except that 10 parts by mass of (A4) was added to the organically treated swellable synthetic fluorinated mica and 30 parts by mass of flat glass fiber (B) was added. The evaluation results are shown in Table 2. As a result, no dent was found in the rib portion and the tensile strength at break was high.
Example 5
A resin composition was obtained in the same manner as in Example 1 except that 40 parts by mass of (A3) was blended with the organically treated swellable synthetic fluorinated mica and 30 parts by mass of flat glass fiber (B) was blended. The evaluation results are shown in Table 2. As a result, no dent was found in the rib portion and the tensile strength at break was high.
Example 6
A resin composition was obtained in the same manner as in Example 1 except that 10 parts by mass of (A5) was blended with organically treated montmorillonite and 30 parts by mass of flat glass fiber (B) was blended. The evaluation results are shown in Table 2. As a result, no dent was found in the rib portion and the tensile strength at break was high.
Example 7
A resin composition was obtained in the same manner as in Example 1 except that 10 parts by mass of (A3) was added to the organically treated swellable synthetic fluorinated mica and 100 parts by mass of flat glass fiber (B) was added. The evaluation results are shown in Table 2. As a result, no dent was found in the rib portion and the tensile strength at break was high.
Example 8
10 parts by mass of swellable synthetic fluorinated mica (A3) organically treated with stearylamine and 30 parts by mass of flat glass fiber (B) having a flat cross section with respect to 100 parts by weight of polyamide 66 resin are continuously determined by Kubota Corporation. Using a supply device, the resin composition is supplied to the main supply port of the same-direction twin screw extruder (TEM 37BS manufactured by Toshiba Machine), melted and kneaded, and taken into a strand from the die, cooled and solidified through a water tank, and then pelletized. To obtain pellets of the resin composition. Extrusion conditions were a temperature setting of 260 to 280 ° C., a screw rotation speed of 250 rpm, a discharge rate of 35 kg / h, and a resin temperature of the resin composition from the die was 270 ° C. Next, the obtained resin composition pellets were injection-molded using an injection molding machine (EC100 manufactured by Toshiba Machine Co., Ltd.) under conditions of a cylinder temperature of 270 ° C. and a mold temperature of 100 ° C. to produce physical property measurement test pieces, and various evaluation tests Went. The evaluation results are shown in Table 2. As a result, no dent was found in the rib portion and the tensile strength at break was high.
Example 9
Continuous determination of 10 parts by mass of swellable synthetic fluorinated mica (A3) organically treated with stearylamine and 30 parts by mass of flat glass fiber (B) having a flat cross section with respect to 100 parts by mass of polyamide 11 resin. Using a supply device, the resin composition is supplied to the main supply port of the same-direction twin screw extruder (TEM 37BS manufactured by Toshiba Machine), melted and kneaded, and taken into a strand from the die, cooled and solidified through a water tank, and then pelletized. To obtain pellets of the resin composition. The extrusion conditions were a temperature setting of 210 to 240 ° C., a screw rotation speed of 250 rpm, a discharge rate of 35 kg / h, and a resin temperature of the resin composition from the die was 230 ° C. Next, the obtained resin composition pellets were injection-molded using an injection molding machine (EC100 manufactured by Toshiba Machine Co., Ltd.) under conditions of a cylinder temperature of 230 ° C. and a mold temperature of 100 ° C. to create physical property measurement test pieces, and various evaluation tests Went. The evaluation results are shown in Table 2. As a result, no dent was found in the rib portion and the tensile strength at break was high.
Example 10
A resin composition was obtained in the same manner as in Example 1, except that 10 parts by mass of (A6) was added to the organically treated swellable synthetic fluorinated mica and 30 parts by mass of flat glass fiber (B) was added. The evaluation results are shown in Table 2. As a result, no dent was found in the rib portion and the tensile strength at break was high.

Comparative Example 1
A resin composition was obtained in the same manner as in Example 3 except that no swellable fluoromica was added. The evaluation results are shown in Table 3. Since the swelling fluorine mica was not used, a dent was seen in the rib portion.

Comparative Example 2
A resin composition was obtained in the same manner as in Example 3 except that the blending amount of the swellable fluorinated mica (A3) was 0.5 parts by mass with respect to 100 parts by mass of the polyamide 6 resin. The evaluation results are shown in Table 3. The tensile breaking strength was inferior to that of Example 3 because the compounding amount of the swellable synthetic fluorine mica was small. Moreover, the dent was seen by the rib part.
Comparative Example 3
A resin composition was prepared in the same manner as in Example 3 except that the amount of the swellable synthetic fluorinated mica (A3) was 60 parts by mass with respect to 100 parts by mass of the polyamide 6 resin. However, since the compounding amount of the swellable synthetic fluorinated mica was too large, the strand could not be drawn at the time of kneading, and the resin pellet could not be obtained.
Comparative Example 4
A resin composition was obtained in the same manner as in Example 3 except that the swellable synthetic fluoromica (A7) treated with 6-aminocaproic acid was used and the blending amount was 10 parts by mass. The evaluation results are shown in Table 3. Although no dent was observed in the rib portion, when the interlayer treating agent of the swellable synthetic fluoromica was general 6-aminocaproic acid, the synergistic effect of the flat glass fiber having a flat cross section and the swellable synthetic fluoromica was not seen. In addition, the adhesion between the flat glass fiber having a flat cross section and the resin was poor, and the tensile strength at break was also inferior to that of Example 3.
Comparative Example 5
A resin composition was obtained in the same manner as in Example 3 except that the swellable synthetic fluorinated mica (A8) having an interlayer amine amount of 0.1 parts by mass was used and the blending amount was 10 parts by mass. The evaluation results are shown in Table 3. Although no dent was observed in the rib portion, the adhesiveness between the flat glass fiber having a flat cross section and the resin was poor and the tensile strength at break was also inferior to that of Example 3 because the amount of interlayer amine was small.
Comparative Example 6
A resin composition was obtained in the same manner as in Example 3 except that the swellable synthetic fluorinated mica (A9) having an interlayer amine amount of 35 parts by mass was used and the blending amount was 10 parts by mass. Since the compounding amount of stearylamine exceeded the range of the present invention, the excess stearylamine reduced the tensile strength at break of the polyamide resin composition.
Comparative Example 7
A resin composition was obtained in the same manner as in Example 3, except that swellable synthetic fluoromica (A10) not treated with an interlayer treating agent was used and the blending amount was 10 parts by mass. The evaluation results are shown in Table 3. As in Comparative Example 4, no dent was found in the rib portion, but no synergistic effect was observed between the glass fiber and the swellable synthetic fluorine mica, and the adhesion between the glass fiber and the resin was poor, and the tensile strength at break was also low. Inferior to Example 3.
Comparative Example 8
A resin composition was obtained in the same manner as in Example 3 except that glass fiber (C) having a circular cross section was used and the blending amount was 10 parts by mass. The evaluation results are shown in Table 3. As in Comparative Example 4, no dent was found in the rib portion, but no synergistic effect was observed between the glass fiber and the swellable synthetic fluorine mica, and the adhesion between the glass fiber and the resin was poor, and the tensile strength at break was also low. Inferior to Example 3.
Comparative Example 9
A resin composition was prepared in the same manner as in Example 3 except that 200 parts by weight of flat glass fiber having a flat cross-section was blended with respect to 100 parts by weight of polyamide 6 resin. The strands were not drawn during kneading, and resin pellets could not be obtained.
Comparative Example 10
Tensile breaking strength and sink marks were also observed for polyamide 6 resin containing no swellable synthetic fluorine mica or glass fiber. The evaluation results are shown in Table 3. Since there was no reinforcement effect of the polyamide resin by the inorganic filler, the tensile strength at break was 78 MPa, which was practically too low.
Comparative Example 11
In Comparative Example 2, a polyamide resin composition was prepared using polyamide 66 instead of polyamide 6. The tensile strength at break was 160 MPa, and dents were observed in the rib portions.
Comparative Example 12
In Comparative Example 2, a polyamide resin composition was prepared using polyamide 11 instead of polyamide 6. The tensile strength at break was 120 MPa, and dents were found in the rib portions.

As is apparent from Tables 2 and 3, the polyamide resin composition reinforced with flat glass fibers has a tendency to cause sink marks and inferior mechanical properties, but the flat glass fibers and the swellable layered silicate By using together, a reinforced polyamide resin composition with improved mechanical properties, particularly sink marks, was obtained.

Claims (4)

A swellable layered silicate (A) in which 0.5 to 30 parts by mass of an aliphatic primary amine is inserted between layers with respect to 100 parts by mass of a swellable layered silicate, and a minor axis of 3 to 10 μm and a major axis / A polyamide resin composition obtained by mixing a flat glass fiber (B) having a flat cross-section with a minor axis ratio of 1.5 to 10, wherein the swelling shown in (A) with respect to 100 parts by mass of the polyamide resin A reinforced polyamide resin composition obtained by mixing 1 to 50 parts by mass of a layered silicate and 5 to 150 parts by mass of flat glass fibers having a flat cross section represented by (B). The aliphatic primary amine is any one or a mixture of octylamine, nonylamine, decylamine, undecylamine, dodecylamine, tridecylamine, tetradecylamine, pentadecylamine, stearylamine and oleylamine. The reinforced polyamide resin composition described. The reinforced polyamide resin composition according to any one of claims 1 to 2, wherein the swellable layered silicate is represented by the following formula (1).
M _α (Mg _X Li _β ) Si ₄ O _Y F _Z (1)
(In the formula, M represents an ion-exchangeable cation, specifically sodium or lithium. Α, β, X, Y, and Z each represents a coefficient, and 0 ≦ α ≦ 1.0. 0 ≦ β ≦ 1.0, 2.5 ≦ X ≦ 4, 10 ≦ Y ≦ 15, 1.0 ≦ Z ≦ 2.0) The reinforced polyamide resin composition according to any one of claims 1 to 2, wherein the swellable layered silicate is represented by the following formula (2).
M _a Si (Al _2-a Mg) O ₁₀ (OH) ₂ .nH ₂ O (2)
(In the formula, M represents a cation such as sodium, and 0.25 ≦ a ≦ 0.7. The number of water molecules bonded to the interlayer ion-exchangeable cation depends on conditions such as cation species and humidity. (It is expressed as nH ₂ O in the formula)