JP6619188B2 - Polyamide resin composition and molded article comprising the same - Google Patents

Description

  The present invention relates to a polyamide resin composition having a metallic tone that is excellent in luminance, glossiness, and profound feeling.

A molded body formed of a thermoplastic resin such as a polyamide resin is generally used for an interior / exterior cover of an automobile engine cover or home appliance.
The appearance of such a resin molded body may require a metallic color tone such as steel or aluminum alloy. In particular, in recent years, there has been an increasing demand for aesthetics of resin moldings, and the appearance of resin moldings is required not only to have a metallic color tone, but also to have a glossy feeling and a high luster feeling. . In addition, various kinds of metallic tones are required, from silver-gray to slightly whiteish gray.

  In order to satisfy such requirements, conventionally, a method of applying a paint containing metal powder such as aluminum on the surface of a resin molded body, so-called metallic coating, has been performed. However, since this metallic coating uses an organic solvent, there is a problem in terms of working environment, and there is a problem that productivity is inferior and cost is high.

As a method for solving the above problems, a resin composition obtained by filling a thermoplastic resin such as a polyamide resin with metallic particles such as aluminum or glossy particles whose surfaces such as mica, wollastonite, and glass are coated with a metal. It has been proposed to use things.
For example, Patent Document 1 discloses a polyamide resin composition in which particles expressing a metallic color are blended with a polyamide resin in which layered silicate is uniformly dispersed at a molecular level. Patent Document 2 discloses a polyamide resin composition containing a polyamide resin and metal flakes.

International Publication No. 99/13006 Pamphlet Special table 2001-509524 gazette

However, the molded products obtained from the polyamide resin compositions described in Patent Documents 1 and 2 can have a metallic metallic feeling, but their texture is insufficient compared to painting and plating. Therefore, the provision of a more profound feeling has been demanded.
An object of the present invention is to provide a metallic polyamide resin composition excellent in all of brightness, glossiness, and profound feeling.

The present inventors have reached the present invention as a result of intensive studies in order to solve such problems.
That is, the gist of the present invention is as follows.

(1) 100 parts by mass of polyamide resin (A), 1 to 10 parts by mass of swellable layered silicate (B), 3 to 8 parts by mass of metallic pigment (C) having an average particle diameter of 5 to 16 μm, and a black pigment And a polyamide resin composition containing 0.05 to 0.8 parts by mass of the black dye (D).
(2) The polyamide resin (A) is a mixture of polyamide 6 and polyamide 11 and / or polyamide 12, and the polyamide 6 content in the polyamide resin (A) is 50 to 95% by mass. Polyamide resin composition.
(3) The polyamide resin composition according to (1) or (2), wherein the metallic pigment (C) having an average particle diameter of 5 to 16 μm is aluminum.
(4) The relationship between the content of the metallic pigment (C) having an average particle diameter of 5 to 16 μm, the black pigment and the black dye (D) is in the range of (C) / (D) = 3.75-60. The polyamide resin composition according to any one of (1) to (3).
(5) A molded article comprising the polyamide resin composition according to any one of (1) to (4).

  According to the present invention, a metallic polyamide resin composition excellent in all of brightness, glossiness and profound feeling can be obtained. Such a polyamide resin composition can be suitably used for applications such as automobile interior parts.

It is the schematic which shows the measuring method of L ^* of the surface of the molded object which consists of a polyamide resin composition of this invention.

  The polyamide resin (A) used in the present invention is not particularly limited. For example, polycaproamide (polyamide 6), polytetramethylene adipamide (polyamide 46), polyhexamethylene adipamide (polyamide 66), polycaproamide. Proamide / polyhexamethylene adipamide copolymer (polyamide 6/66), polyundecamide (polyamide 11), polycaproamide / polyundecamide copolymer (polyamide 6/11), polydecanamide (polyamide 12), polycapro Crystalline polyamides such as amide / polydodecamide copolymer (polyamide 6/12), polyhexamethylene sebamide (polyamide 610), polyhexamethylene dodecamide (polyamide 612), polyundecamethylene adipamide (polyamide 116) And a mixture of these Or polymers thereof. Among these, polyamide 6, polyamide 66, polyamide 11 and polyamide 12 are preferable in terms of excellent metallic color developability and brightness. In addition, polyamide 6 and polyamide are improved in terms of improvement in light resistance, heat discoloration resistance and moisture and heat resistance. 11 and / or a mixture with polyamide 12 is more preferred.

When a mixture of polyamide 6 and polyamide 11 and / or polyamide 12 is used as the polyamide resin (A), the content of polyamide 6 in the polyamide resin (A) is preferably 50 to 95% by mass, 60 to More preferably, it is 90 mass%, and it is further more preferable that it is 70-85 mass%. By using the polyamide mixture, it is possible to suppress precipitation of oligomers or the like mainly resulting from polyamide 6 under wet heat conditions. When the content of polyamide 6 is less than 50% by mass, the heat resistance may be insufficient, and when it exceeds 95% by mass, the light resistance, heat discoloration resistance, and moist heat resistance may not be sufficient.
The mixture of polyamide 6 and polyamide 11 and / or polyamide 12 may be a copolymer even if the homopolymer of polyamide 6 and the homopolymer of polyamide 11 and / or polyamide 12 are melt-mixed. It may be a thing.

  When the polyamide resin (A) is a copolymer composed of polyamide 6, polyamide 11 and / or polyamide 12, 6-aminocaproic acid units, 11-aminoundecanoic acid units and / or 12-aminododecanoic acid units, It is preferable that it is a copolymer comprised from these. That is, the polyamide resin (A) is a polyamide 6 / polyamide 11 copolymer (nylon 6/11), a polyamide 6 / polyamide 12 copolymer (nylon 6/12), or a polyamide 6 / polyamide 11 / polyamide 12 copolymer (nylon 6 / 11/12).

  The relative viscosity, which is an index of the molecular weight of the polyamide resin (A), is not particularly limited, but the relative viscosity measured under the conditions of 96 mass% concentrated sulfuric acid as a solvent at a temperature of 25 ° C. and a concentration of 1 g / dl is 1.5 to 3.5 is preferable, 1.7 to 3.2 is more preferable, and 1.9 to 3.0 is even more preferable. If the relative viscosity is less than 1.5, the resulting molded article of the polyamide resin composition may be inferior in light resistance, heat discoloration resistance, and heat and humidity resistance. On the other hand, if the relative viscosity exceeds 3.5, the fluidity is inferior, the kneading becomes difficult, and the moldability is lowered, so the luminance may be inferior.

  The polyamide resin composition of the present invention contains a metallic pigment (C) in order to improve the brightness of the resulting molded article, but together with the metallic pigment (C), a specific amount of swellable layered silicate ( It is necessary to contain B) simultaneously. By containing the swellable layered silicate (B), the dispersibility of the metallic pigment (C) can be improved, and by improving the dispersibility of the metallic pigment (C), the clear feeling is improved and the metallic Even if there is little content of a pigment (C), the clear feeling of a molded object can be improved efficiently.

  The swellable layered silicate (B) used in the present invention may be naturally produced or artificially synthesized or modified, for example, smectite group (montmorillonite, beidellite, hectorite, soconite, etc.), vermiculite group ( Vermiculite, etc.), mica family (fluorine mica, muscovite, paragonite, phlogopite, lepidrite, etc.), brittle mica family (margarite, clintonite, anandite, etc.), chlorite group (donbasite, suduaite, kukeite, clinochlore, chamo) Night, nimite, etc.). In the present invention, swellable fluorine mica, montmorillonite and hectorite are particularly preferably used, and two or more kinds may be used in combination.

The swellable fluorine mica preferably used in the present invention generally has a structural formula represented by the following formula.
M _a (Mg _X Li _b ) Si ₄ O _Y F _Z
(In the formula, M represents an ion-exchangeable cation, and specific examples include sodium and lithium. A, b, X, Y, and Z each represents a coefficient, and 0 ≦ a ≦ 0.5. 0 ≦ b ≦ 0.5, 2.5 ≦ X ≦ 3, 10 ≦ Y ≦ 11, 1.0 ≦ Z ≦ 2.0.)

As a method for producing such a swellable fluorinated 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.
Further, there is 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. 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. When it is outside this range, the yield of the 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 syrup treatment or the like.
M _a Si (Al ₂ -aMg) O ₁₀ (OH) ₂ .nH ₂ O
(In the formula, M represents a cation such as sodium, and 0.25 ≦ a ≦ 0.6. Further, the number of water molecules bonded to the ion-exchangeable cation between layers depends on conditions such as cation species and humidity. (It is represented by nH ₂ O 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.

The hectorite used in the present invention is represented by the following formula, and may be naturally obtained or may be obtained by synthesis.
Na _0.66 (Mg _5.34 Li _0.66 ) Si ₈ O ₂₀ (OH) ₄ .nH ₂ O
Hectorite has a structure composed of a negatively charged silicate layer mainly composed of silicate and a cation having an ion exchange ability interposed between the layers, and compared with other swellable layered silicates, Since many hydroxyl groups are contained, water molecules are likely to enter between layers (that is, highly hydrophilic) and easily swell. In addition, the particle size is small compared to other swellable layered silicates.

  The content of the swellable layered silicate (B) is required to be 1 to 10 parts by mass, preferably 2 to 9 parts by mass, with respect to 100 parts by mass of the polyamide resin (A). It is more preferably 8 parts by mass. By including a predetermined amount of the swellable layered silicate (B), when the molded body obtained is directly viewed from a certain angle, it has a metallic feeling in each part of the three-dimensional part, and has a profound feeling In other words, it can be formed into a molded body with a more metallic stereoscopic effect. When the content of the swellable layered silicate (B) is less than 1 part by mass, a profound feeling cannot be obtained. On the other hand, when the content exceeds 10 parts by mass, the surface glossiness and luminance of the obtained molded product are lowered.

  In the polyamide resin composition of the present invention, the metallic pigment (C) having an average particle diameter of 5 to 16 μm is not particularly limited as long as it has the average particle diameter. Since the polyamide resin composition of the present invention is intended to improve the metallic color developability, brightness, and profound feeling of the molded article obtained, it is necessary to increase the content of the metallic pigment in the polyamide resin composition. Usually, those having an average particle size of 20 to 40 μm are used as metallic pigments. However, if such a material having an average particle size is highly filled in the polyamide resin composition, the metallic pigments are secondarily aggregated. Or the surface smoothness was impaired, or rather the surface appearance of the molded body was impaired. In the present invention, by using the metallic pigment (C) having a specific average particle diameter, it is possible to contain a lot of metallic pigment in the polyamide resin composition without impairing the surface appearance of the molded body. It was. Further, when used in combination with the above-described swellable layered silicate (B), a solid feeling could be enhanced without particularly impairing the metallic color developability and brightness.

  The average particle diameter of the metallic pigment (C) is 5 to 16 μm, preferably 6 to 14 μm, more preferably 7 to 12 μm, and further preferably 8 to 10 μm. When the average particle diameter of the metallic pigment (C) is less than 5 μm, it is difficult to obtain a luminance feeling. When the average particle diameter exceeds 16 μm, the content of the metallic pigment (C) to be contained in the polyamide resin composition is sufficiently increased. Even if it cannot be contained, the profound feeling of the resulting molded article is impaired.

  The average particle diameter of the metallic pigment (C) can be measured by a laser diffraction / scattering particle size distribution measuring device, for example, Microtrack 2 (manufactured by Nikkiso Co., Ltd.).

The average thickness of the metallic pigment (C) is preferably 1 to 30 μm, more preferably 1 to 20 μm, and still more preferably 1 to 10 μm. The metallic pigment (C) having an average thickness of less than 1 μm is inferior in rigidity and it is difficult to maintain the shape when melt-mixed, and thus it is difficult to obtain a molded body having sufficient glossiness. On the other hand, the metallic pigment (C) having an average thickness of more than 30 μm has a reduced orientation, and the resulting molded product is inferior in luminance.
The average thickness of the metallic pigment (C) can be calculated by a simple average of 50 metallic pigments measured with an electron microscope.

The aspect ratio (average particle diameter / average thickness) of the metallic pigment (C) is preferably 2 to 60, more preferably 2 to 50, and further preferably 2 to 30. When the aspect ratio is less than 2, the brightness of the obtained molded article is inferior. Those having an aspect ratio exceeding 60 are difficult to obtain industrially, and even if obtained, the dispersion stability is inferior, and the surface smoothness of the resulting molded article is impaired.
The aspect ratio of the metallic pigment (C) can be obtained by dividing the value of the average particle diameter by the average thickness value.

  A well-known thing can be used for the metallic pigment (C) whose average particle diameter is 5-16 micrometers. As the metallic pigment (C), for example, any one or a group of metals consisting of aluminum, iron, nickel, chromium, tin, zinc, indium, titanium, silicon, and copper, or a plurality of these groups of metals are used. Examples thereof include metal powder pigments made of any of the alloys used, or a group of these metals or oxides, nitrides, sulfides or carbides of the alloys. In addition, titanium-coated mica can also be used. Among these, aluminum is preferable because it imparts metallic color developability and brightness to the polyamide resin composition, and is easy to improve the solid feeling.

  The content of the metallic pigment (C) is required to be 3 to 8 parts by mass, preferably 3.5 to 7.5 parts by mass with respect to 100 parts by mass of the polyamide resin (A). More preferably, it is -7 mass parts. When the content of the metallic pigment (C) is less than 3 parts by mass, the resulting molded article cannot have a profound feeling. On the other hand, if the amount exceeds 8 parts by mass, the molded article has reduced brightness and surface gloss.

  The polyamide resin composition of the present invention needs to contain a black pigment or a black dye (D). The black pigment is not particularly limited, and examples thereof include carbon black, acetylene black, lamp black, bone black, graphite, iron black, aniline black, cyanine black, and titanium black. Among these, carbon black is particularly preferable because the effects of the present invention can be easily expressed. The black dye is not particularly limited, and examples thereof include azine dyes containing nigrosine and polycyclic condensed dyes containing anthraquinone. Among them, azine dyes are preferable because they are easy to handle. For example, NYB27620B (manufactured by Sanyo Chemical Co., Ltd.), Orient Spirit BlackSB (manufactured by Orient Chemical Industry Co., Ltd.), Spirit Black No. Commercially available products such as 850 (manufactured by Sumitomo Chemical Co., Ltd.) and Nigrosine Base LK (manufactured by BASF) can be used. The black pigment or black dye (D) may be used alone or in combination.

  Among the azine dyes, nigrosine is particularly preferable. Nigrosine includes COLOR INDEX and C.I. I. SOLVENT BLACK 5 and C.I. I. Mention may be made of black azine-based condensation mixtures such as those described as SOLVENT BLACK 7. Such nigrosine can be synthesized, for example, by oxidizing and dehydrating aniline, aniline hydrochloride and nitrobenzene at a reaction temperature of 160 to 180 ° C. in the presence of iron chloride. Further, purified nigrosine obtained by purifying the nigrosine thus obtained to make aniline or diphenylamine less than 0.1% is more preferable. As such nigrosine, Cramitity 81 and NUBIAN BLACK series manufactured by Orient Chemical Industries are commercially available.

  The content of the black pigment or black dye (D) is required to be 0.05 to 0.8 parts by mass with respect to 100 parts by mass of the polyamide resin (A), and 0.1 to 0.7 parts by mass. It is preferable that it is 0.3-0.6 mass part. When the content of the black pigment or the black dye (D) is less than 0.05 parts by mass, a profound feeling in the resulting molded article cannot be obtained. On the other hand, when it exceeds 0.8 parts by mass, the molded article has a dull gloss like lead, and the luminance decreases.

  The relationship between the content of the metallic pigment (C) having an average particle size of 5 to 16 μm and the black pigment or black dye (D) is preferably in the range of (C) / (D) = 3.75-60. 5 to 50 (mass ratio) is more preferable, and 6 to 40 (mass ratio) is more preferable. By being (C) / (D) = 3.75 to 60 (mass ratio), it is possible to increase the solid feeling in a well-balanced manner while improving the metallic feeling and the luminance. When (C) / (D) is less than 3.75, the profound feeling increases, but the luminance may be insufficient. When (C) / (D) exceeds 60, the profound feeling may be insufficient.

  A pigment, a plasticizer, a lubricant, a release agent, an antistatic agent, and the like can be added to the polyamide resin composition of the present invention as long as the characteristics are not significantly impaired. The method of mixing these with the polyamide resin composition of the present invention is not particularly limited. In addition, in order to assist particularly in flame retardancy, a condensed phosphate ester, polyphosphoric acid, a nitrogen compound flame retardant and the like may be added.

Next, the manufacturing method of the polyamide resin composition of this invention is demonstrated.
In the present invention, the polyamide resin composition can be produced by melt-kneading the polyamide resin (A), the swellable layered silicate (B), and the metallic pigment (C).
In the present invention, the polyamide resin (A) and the swellable layered silicate (B) obtained by polymerizing the monomer component constituting the polyamide resin (A) in the presence of the swellable layered silicate (B). It is preferable to produce a polyamide resin composition by melt-mixing the mixture and the metallic pigment (C) using a mixture of
In the presence of the swellable layered silicate (B), the monomer component constituting the polyamide resin (A) is polymerized to disperse the swellable layered silicate (B) uniformly in the polyamide resin (A). And the glossiness of the resulting molded article can be further increased.
As the monomer used in the polymerization reaction, an aminocarboxylic acid or a lactam thereof can be used. Therefore, the lactam may be used as an aminocarboxylic acid as a raw material for the polymerization reaction.

  When the polyamide resin (A) is a copolymer composed of two or more aminocarboxylic acid units, two or more aminocarboxylic acids (lactams) in the presence of the swellable layered silicate (B) It is preferable to produce a polyamide resin composition by melt-mixing the mixture and the metallic pigment (C) using a mixture obtained by carrying out the copolymerization reaction.

  In the case where the polyamide resin (A) is a molten mixture of two or more polymers composed of aminocarboxylic acid units, the polymerization reaction of at least one of the two or more polymers is performed. In the presence of the swellable layered silicate (B), a mixture of the resulting polymer and the swellable layered silicate (B) and another polymer (or other polymer and the swellable layered silicate (B) )) And the metallic pigment (C) are preferably melt-mixed to produce a polyamide resin composition. The aminocarboxylic acid that undergoes the polymerization reaction in the presence of the swellable layered silicate (B) is highly effective in uniformly dispersing the swellable layered silicate (B). Preferably there is.

  When two or more types of molten mixtures of polymers composed of aminocarboxylic acid units are used as the polyamide resin (A), they are preferably sufficiently melt-kneaded. When melt kneading is insufficient, for example, when the difference in melt viscosity between the two polyamide resins to be melt-mixed is large, or when the difference in melting point is large, a sea-island structure is exhibited without being uniformly mixed with each other. There is. In such a case, particularly in the present invention, it is difficult to uniformly orient the contained metallic pigment (C) when obtaining a molded article, so that the luminance is partially impaired or luminance is uneven. Inconvenience may occur. Such a concern is reduced when a copolymer composed of two or more aminocarboxylic acid units is used as the polyamide resin (A).

As a method of polymerizing aminocarboxylic acid (lactam) in the presence of the swellable layered silicate (B), water is prepared after charging the swellable layered silicate (B) and aminocarboxylic acid (lactam) in an autoclave. The method of melt polycondensation method is used within the range of temperature 240-300 degreeC, pressure 0.2-3MPa, 1-15 hours using initiators, such as. In the case of using ε-caprolactam, it is preferable to perform polymerization at a temperature of 250 to 280 ° C, a pressure of 0.5 to 2 MPa, and a range of 3 to 5 hours.
Further, in order to remove aminocarboxylic acid (lactam) remaining in the polyamide resin after polymerization, it is preferable to scour the polyamide resin pellets with hot water, and the condition is 90 to 100 ° C. For 8 hours or more in hot water.

When melt-mixing the mixture of the polyamide resin (A) and the swellable layered silicate (B) and the metallic pigment (C), a known melt-kneading extruder can be used.
In order to suppress crushing or breakage due to kneading of the metallic pigment (C) as much as possible, the screw is preferably used uniaxially rather than biaxially.
As a method for supplying the metallic pigment (C) to the melt-kneading extruder, a mixture of the metallic pigment (C) and the mixture may be added all at once from the main hopper, but the metallic pigment (C) may be crushed or In order to suppress breakage as much as possible, the metallic pigment (C) is preferably supplied from the middle of the extruder with a side feeder, and more preferably supplied downstream of the extruder.
The mixture and the metallic pigment (C) may not be sufficiently melt-kneaded, and may be mixed as long as the operation is not hindered in the subsequent injection molding process. If necessary, a mixture obtained by dry blending the mixture and the metallic pigment (C) may be directly supplied to an injection molding machine, or injection-molding can be performed by melt-kneading in the injection molding machine.
Since the metallic pigment (C) is brittle with respect to external stress, in this way, the screw shear stress during melt kneading should not be applied to the metallic pigment (C) as much as possible in the production of the resin composition and the molding of the molded body. Is preferable for improving the glossiness of the molded article to be obtained.

  The molded article of the present invention is formed by molding the polyamide resin composition of the present invention. Examples of the molding method include injection molding, blow molding, extrusion molding, inflation molding, and post-sheet processing such as vacuum molding, pressure molding, and vacuum / pressure molding. Among these, it is preferable to use the injection molding method. In addition to typical injection molding methods, gas injection molding, injection press molding, and the like can also be employed.

As injection molding conditions suitable for the polyamide resin composition of the present invention, for example, the cylinder temperature is equal to or higher than the melting point or flow start temperature of the resin composition, preferably 190 to 270 ° C., and the mold temperature is ( The melting point is −20 ° C. or less. If the molding temperature is too low, moldability such as short-circuiting in the molded body may become unstable, and glossiness of the surface of the resulting molded body may be lost. On the other hand, when the molding temperature is too high, the polyamide resin composition is decomposed, and the strength of the resulting molded product may be reduced, or the glossiness may be reduced.
The molded product of the present invention, particularly a molded product obtained by the injection molding method, has high brightness, but various conditions during injection molding, such as resin temperature, injection speed, injection pressure, mold temperature, are balanced. By setting, it is possible to further improve the luminance. In addition, these conditions are the fluidity | liquidity in the metal mold | die of the fuse | melted polyamide resin composition, Furthermore, the dispersibility of the swellable layered silicate (B) and a metallic pigment (C) in a polyamide resin composition. It needs to be set carefully because it has an impact. For example, when the injection speed is high, the orientation of the metallic pigment (C) is disturbed and the brightness tends to decrease. Therefore, the injection speed is preferably from low to medium.

The molded article of the present invention is a molded article having a more profound feeling while having both a conventional metallic color developability and luminance. Note that “excellent luminance” means that the brightness in the vicinity of an angle having a regular reflection relationship with the incident angle is high, and the luminance can be evaluated by a value of L ^* 45 described later. Further, increasing the solid feeling means that the details of the shape of the molded product stand out and the metallic three-dimensional feeling increases, and the heavy feeling can be evaluated by a flip-flop value described later.

  Specific examples of the molded article of the present invention include various automobile parts, electric and electronic parts. Since the molded body of the present invention is excellent in brightness, such as metallic luster, especially as a resin part, as an automobile part, various instruments such as a speedometer, a tachometer, a fuel meter, a water temperature meter, a distance meter in an instrument panel, etc. , Car stereos, navigation systems, various switches around air conditioners, buttons, shift levers at the center console, side brake grips, door trims, armrests, door levers, etc. It can be used as a replacement material for plastic parts. As electrical and electronic parts, various parts and casings around a personal computer, cellular phone parts and casings, and other resin parts for electrical appliances such as OA equipment parts can be used. Further, since the profound feeling is increased, the texture is not lowered, and the sense of quality is increased, though the weight is reduced especially with shift levers, side brake grips, door trims, armrests, door levers and the like in automobile parts.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited by these Examples.

1. Evaluation methods

(1) Preparation of Test Pieces 1 and 2 Using the obtained polyamide resin composition, the resin temperature was 260 ° C., the mold temperature was 100 ° C., and the pressure was maintained on an injection molding machine (EC-100II type manufactured by Toshiba Machine Co., Ltd.). Injection molding was performed under the conditions of 30 MPa, an injection speed of 100 mm / s, an injection pressure of 100 MPa, and a cooling time of 10 seconds to obtain a test piece (a plate-like molded body having a length of 90 mm × width 50 mm × thickness 2 mm). A mold having one side gate at the center in the short side direction was used.

(2) Surface glossiness Based on JIS Z8741, the surface glossiness of the test piece 1 was measured with the glossiness meter (Gloss meter VG7000 type | mold by Nippon Denshoku) at the incident angle of 60 degrees.
The case of 90% or more was regarded as acceptable.

(3) Luminance, flip-flop value For specimen 1, using a variable angle spectral color difference meter (variable angle spectral colorimetry system GSP-2 manufactured by Murakami Color Research Laboratory), as shown in FIG. The L ^* value (D65 / 2 light source, field of view 2 °) was measured with an incident angle of −45 ° and a light receiving angle of 45 °, 40 °, and 0 °. In addition, each L ^* value was set to L ^* 45, L ^* 40, L ^* 0.
When L ^* 45, which is an index of luminance, is 400 or more, it was determined to be acceptable.
The flip-flop value was determined by the following formula using L ^* 40 and L ^* 0 as the degree of change in brightness when the surface of the molded product was viewed from the front and oblique directions.
Flip-flop value = 2 × (L ^* 40−Lv0) / (L ^* 40 + L ^* 0)
When the flip-flop value, which is an indicator of profound feeling, was 1.30 or more, it was determined to be acceptable.

2. Raw material (1) Polyamide resin monomer component, ε-caprolactam (manufactured by Ube Industries)

(2) Polyamide resin / Polyamide 11 resin (P-4) (“BMN O” manufactured by Arkema), relative viscosity 1.8

(3) Swellable layered silicate / B-1: Swellable fluoromica (“ME-100” manufactured by Coop Chemical Co.), average particle size 6.0 μm, cation exchange capacity 110 meq / 100 g

(4) Metallic pigment C-1: Aluminum paste ("Silbead M050-AP" manufactured by Asahi Kasei Chemicals Co., Ltd. (average particle size 5 μm, average thickness 0.1 μm, aluminum component 90%, polyethylene glycol 10%)
C-2: Aluminum paste ("Silbeads M100-BP" manufactured by Asahi Kasei Chemicals Corporation (average particle size 10 μm, average thickness 0.2 μm, aluminum component 90%, polyethylene glycol 10%)
C-3: Aluminum paste ("Silbeads M200-BP" manufactured by Asahi Kasei Chemicals Co., Ltd. (average particle size 20 μm, average thickness 0.4 μm, aluminum component 90%, polyethylene glycol 10%)
C-4: Aluminum paste ("Silbeads M350-BP" manufactured by Asahi Kasei Chemicals Corporation (average particle size 35 μm, average thickness 0.4 μm, aluminum component 90%, polyethylene glycol 10%)
C-5: Aluminum paste (“M-601” manufactured by Asahi Kasei Chemicals Corporation (average particle size: 15 μm)

(5) Black pigment D-1: Carbon black (“Raven 5000” manufactured by Columbia, primary particle size: 11 nm)

(6) Black dye D-2: Nigrosine (“Craity 81” manufactured by Orient Chemical Co., Ltd.)

(7) Pigments other than black-E-1: Blue pigment, ultramarine blue

Production Example 1
After 100 parts by mass of ε-caprolactam was charged with 0.4 parts by mass of phosphorous acid, 3 parts by mass of swellable layered silicate (B-1) and 5 parts by mass of water, and stirred at 80 ° C. for 1 hour, 260 Stirring is carried out at 0 ° C. and 0.7 MPa for 1 hour, followed by stirring at 260 ° C. and normal pressure for 1 hour, polymerization is carried out, and polyamide 6 resin containing 3.2% by mass of swellable layered silicate (B-1) ( P-1) was obtained.

Production Example 2
After 100 parts by mass of ε-caprolactam was charged with 0.4 parts by mass of phosphorous acid, 11 parts by mass of swellable layered silicate (B-1), and 5 parts by mass of water and stirred at 80 ° C. for 1 hour, 260 Stirring is carried out at 0 ° C. and 0.7 MPa for 1 hour, followed by stirring at 260 ° C. and normal pressure for 1 hour, polymerization is carried out, and polyamide 6 resin containing 10.0% by mass of swellable layered silicate (B-1) ( P-2) was obtained.

Production Example 3
With respect to 100 parts by mass of ε-caprolactam, 0.4 parts by mass of phosphorous acid and 5 parts by mass of water were charged, stirred at 80 ° C. for 1 hour, then stirred at 260 ° C. and 0.7 MPa for 1 hour, and then 260 Polymerization was carried out by stirring for 1 hour at ° C. and normal pressure to obtain a polyamide 6 resin (P-3).

Example 1
Swellable layered silicate-containing polyamide resin (P-1) obtained in Production Example 1 103.3 parts by mass, metallic pigment (C-2) 3.0 parts by mass, black pigment (D-1) 0.5 parts by mass The parts were mixed together, charged from the main hopper of a single screw extruder, melt kneaded, extruded into a strand from a die, cooled, and pelletized to obtain polyamide resin composition pellets. The melt kneading was performed at a resin temperature of 260 ° C., a screw rotation of 200 rpm, and a discharge rate of 30 kg / h.
A test piece was prepared using the obtained polyamide resin composition, and various evaluations were performed. The results are shown in Table 1.

Examples 2-11, Comparative Examples 1-10
A polyamide resin composition pellet was obtained in the same manner as in Example 1 except that the respective components were blended in the blending amounts shown in Tables 1 and 2, and injection molding was further performed. Various evaluation was performed using the obtained test piece. The results are shown in Tables 1 and 2.
In Example 2, 82.6 parts by mass of the swellable layered silicate-containing polyamide resin (P-1) and 20.0 parts by mass of the polyamide 11 resin (P-3) were mixed and used as the resin component.

  In Examples 1-11, since it followed the predetermined | prescribed mixing | blending, it was able to be set as the polyamide resin composition which was excellent in metallic color development property, the brightness | luminance, and increased the profound feeling.

  In Comparative Example 1, since the swellable layered silicate was not contained, the flip-flop value was low.

  In Comparative Example 2, since the content of the metallic pigment was low, the flip-flop value was low.

  In Comparative Example 3, since the content of the metallic pigment was high, the surface smoothness was impaired and the surface glossiness of the molded article was low.

  In Comparative Example 4, since neither the black pigment nor the black dye was contained, the flip-flop value was low.

  In Comparative Example 5, since the content of the black pigment was low, the flip-flop value was low.

  In Comparative Example 6, since the content of the black pigment was high, the flip-flop value and the luminance were low.

  In Comparative Examples 7 and 8, a metallic pigment having an average particle diameter exceeding a predetermined range was used, so that the flip-flop value was low.

  In Comparative Example 9, since a pigment other than black was used, the flip-flop value was low.

  In Comparative Example 10, since the swellable layered silicate was not contained, the surface glossiness, luminance, and flip-flop value were low.

Claims (5)

100 parts by mass of polyamide resin (A), 1 to 10 parts by mass of swellable layered silicate (B), 3 to 8 parts by mass of metallic pigment (C) having an average particle size of 5 to 16 μm, and black pigment and black dye (D) A polyamide resin composition containing 0.05 to 0.8 parts by mass.   2. The polyamide resin according to claim 1, wherein the polyamide resin (A) is a mixture of polyamide 6 and polyamide 11 and / or polyamide 12, and the polyamide 6 content in the polyamide resin (A) is 50 to 95 mass%. Composition.   The polyamide resin composition according to claim 1 or 2, wherein the metallic pigment (C) having an average particle diameter of 5 to 16 µm is aluminum. The relationship between the content of the metallic pigment (C) having an average particle diameter of 5 to 16 µm, the black pigment and the black dye (D) is in the range of (C) / (D) = 3.75-60. The polyamide resin composition in any one of 1-3. The molded object which consists of a polyamide resin composition in any one of Claims 1-4.