JP2016069584A - Polyamide resin composition and molded body by molding the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyamide resin composition excellent in metallic color development and brightness and having suppressed discoloration, suitably used for applications such as an automobile interior member with capability to maintain a metallic color tone and enhance designability over a long time.SOLUTION: There is provided a polyamide resin composition containing total 100 pts.mass of (A) an aliphatic polyamide rein of 60 to 95 pts.mass and (B) an aromatic polyamide resin of 5 to 40 pts.mass, 1 to 10 pts.mass of (C) a swellable layer silicate, 0.5 to 5 pts.mass of (D) a metallic pigment and 0.05 to 0.8 pts.mass of (E) a coloring agent.SELECTED DRAWING: None

Description

  The present invention relates to a polyamide resin composition that is excellent in metallic color developability and luminance and in which fading is suppressed.

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 the 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 appearance and a high luster. . 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 work environment, and there is also a problem that the productivity is inferior and the cost is high.

As a method for solving the above problems, a resin composition obtained by filling a thermoplastic resin such as polyamide resin with metallic particles such as aluminum or glossy particles whose surfaces such as mica, wollastonite and glass are coated with metal. It has been proposed to mold using objects.
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.
In addition, moldings that are colored with various metallic colors such as red metallic and black metallic other than the silver color by adding an aluminum pigment have improved design and are used in various applications.

International Publication No. 99/13006 Pamphlet Special table 2001-509524 gazette JP 2004-250562 A

The present inventors have found that in molded articles obtained from the polyamide resin compositions described in Patent Documents 1 and 2, there is a problem that fading easily occurs when toning each color using a colorant. It was. As the colorant, a pigment or a dye is usually used depending on the application. In the case of coloring in a vivid color, a pigment and a dye are used in combination, but the light resistance is inferior.
An object of the present invention is to provide a polyamide resin composition which is excellent in metallic color developability and luminance and in which fading is suppressed.

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) For a total of 100 parts by mass of the aliphatic polyamide resin (A) 60 to 95 parts by mass and the aromatic polyamide resin (B) 5 to 40 parts by mass, the swellable layered silicate (C) 1 to 10 parts by mass, A polyamide resin composition containing 0.5 to 5 parts by weight of a metallic pigment (D) and 0.05 to 0.8 parts by weight of a colorant (E).
(2) The polyamide resin composition according to (1), wherein the aromatic polyamide resin (B) is an amorphous polyamide.
(3) The dye (e1) and the pigment (e2) are contained as the colorant (E), and (e1) / (e2) = 80/20 to 50/50 (mass ratio) (1) or (2 ) Polyamide resin composition.
(4) The polyamide resin composition according to (1) to (3), wherein the colorant (E) is a red or yellow colorant.
(5) The polyamide resin composition according to any one of (1) to (4), further comprising a weathering agent (F).
(6) A molded product obtained by molding the polyamide resin composition of (1) to (5).

According to the present invention, a polyamide resin composition excellent in metallic color developability and luminance and suppressed in fading can be obtained.
Such a polyamide resin composition can be suitably used for applications such as automobile interior parts, maintaining a metallic color tone and improving designability over a long period of time.

  The polyamide resin composition of the present invention is a swellable layered silicate (C) with respect to 100 parts by mass in total of 60 to 95 parts by mass of the aliphatic polyamide resin (A) and 5 to 40 parts by mass of the aromatic polyamide resin (B). 1 to 10 parts by mass, 0.5 to 5 parts by mass of a metallic pigment (D) and 0.05 to 0.8 parts by mass of a colorant (E).

  The aliphatic 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 / polyhexamethylene adipamide copolymer (polyamide 6/66), polyundecamide (polyamide 11), polycaproamide / polyundecamide copolymer (polyamide 6/11), polydecamide (polyamide 12), Crystals of polycaproamide / polydodecamide copolymer (polyamide 6/12), polyhexamethylene sebamide (polyamide 610), polyhexamethylene dodecamide (polyamide 612), polyundecamethylene adipamide (polyamide 116), etc. Polyamides and these Mixture or polymers thereof. Among these, polyamide 6, polyamide 66, polyamide 11, and polyamide 12 are preferable from the viewpoint of excellent metallic color development and luminance, and in addition, polyamide 6 and polyamide are improved in light resistance, heat discoloration resistance, and heat and humidity resistance. 11 and / or mixtures with polyamide 12 are particularly 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 aromatic polyamide resin (B) used in the present invention is not particularly limited. For example, polyhexamethylene terephthalamide (nylon 6T), polyhexamethylene terephthalamide / isophthalamide (nylon 6T / 6I), polybis (4-amino) Cyclohexyl) methane dodecamide (nylon PACM12), polybis (3-methyl-4-aminocyclohexyl) methane dodecamide (nylon dimethyl PACM12), polymetaxylylene adipamide (nylon MXD6), polynonamethylene terephthalamide (nylon 9T) , Polydecamethylene terephthalamide (nylon 10T), polyundecamethylene terephthalamide (nylon 11T), polyundecamethylene hexahydroterephthalamide (nylon 11T (H)), etc. , Isophthalic acid / terephthalic acid / 1,6-hexanediamine / bis (3-methyl-4-aminocyclohexyl) methane polycondensate, terephthalic acid / 2,2,4-trimethyl-1,6-hexanediamine / 2 , 4,4-Trimethyl-1,6-hexanediamine polycondensate, isophthalic acid / bis (3-methyl-4-aminocyclohexyl) methane / ω-laurolactam polycondensate, isophthalic acid / terephthalic acid / 1 , 6-hexanediamine polycondensate, isophthalic acid / 2,2,4-trimethyl-1,6-hexanediamine / 2,4,4-trimethyl-1,6-hexanediamine polycondensate, isophthalic acid / A polycondensate of terephthalic acid / 2,2,4-trimethyl-1,6-hexanediamine / 2,4,4-trimethyl-1,6-hexanediamine; Amorphous polyamides such as polycondensates of sophthalic acid / bis (3-methyl-4-aminocyclohexyl) methane / ω-laurolactam, polycondensates of phthalic acid / terephthalic acid / other diamine components, and the like can be mentioned. The amorphous polyamide is a polyamide having an aromatic ring or alicyclic structural unit in the main chain, and is a substantially amorphous transparent polyamide or copolyamide.

  The aromatic polyamide resin (B) is preferably an amorphous polyamide in terms of improving the light resistance and improving the surface appearance of the molded article obtained, and is preferably isophthalic acid / terephthalic acid / 1,6-hexanediamine. A polycondensate of the above, a polycondensate of isophthalic acid / terephthalic acid / 1,6-hexanediamine / bis (3-methyl-4-aminocyclohexyl) methane or a mixture thereof can be more preferably used. Two or more of these amorphous polyamide resins can be used in combination.

  In the present invention, the aliphatic polyamide resin (A) and the aromatic polyamide resin (B) are (A) / (B) = 60/40 to 95/5 (mass ratio), and 65/35 to 90/10. (Mass ratio) is preferred, 70/30 to 85/15 (mass ratio) is more preferred, and 75/25 to 80/20 (mass ratio) is even more preferred. When the content of the aliphatic polyamide resin (A) is less than 60% by mass, the metallic color developability is inferior, and when the content of the aromatic polyamide resin is less than 5% by mass, the light resistance and the surface glossiness are inferior.

Note that crystalline polyamide and amorphous polyamide can be distinguished by the value of heat of crystal fusion. The heat of crystal fusion indicates the heat of fusion of the crystal phase measured by a differential scanning calorimeter (DSC) under a nitrogen atmosphere at a rate of temperature increase of 16 ° C./min, and is represented by the endothermic peak of the melting endothermic curve. It can be calculated from the size of the area to be measured. A large area represented by the endothermic peak of the melting endothermic curve indicates that the amount of heat of crystal fusion, that is, easy crystallization. Amorphous polyamide has a heat of crystal fusion of 1 cal / g or less, indicating that it is difficult to crystallize.
Here, the crystalline polyamide includes both a crystalline polyamide as the aliphatic polyamide resin (A) and a crystalline polyamide as the aromatic polyamide resin (B).

  The relative viscosity, which is an index of the molecular weight of the aliphatic polyamide resin (A) or the aromatic polyamide resin (B), is not particularly limited. However, 96 mass% concentrated sulfuric acid is used as a solvent, the temperature is 25 ° C., and the concentration is 1 g / dl. The measured relative viscosity is preferably 1.5 to 3.5, more preferably 1.7 to 3.2, and even more preferably 1.9 to 3.0. 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 that the luminance may be inferior.

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

  The swellable layered silicate (C) used in the present invention may be naturally occurring or artificially synthesized or modified, for example, smectite group (montmorillonite, beidellite, hectorite, soconite, etc.), vermiculite group ( Vermiculite, etc.), mica (fluorine mica, muscovite, paragonite, phlogopite, lepidrite, etc.), brittle mica (margarite, clintonite, anandite, etc.), chlorite (donbasite, sudoite, kukeite, clinochlore, chamo) Night, nimite, etc.). In the present invention, Na-type or Li-type swellable fluorinated mica, montmorillonite, and hectorite are particularly preferably used, and two or more types 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. 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. 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-a Mg) O ₁₀ (OH) ₂ .nH ₂ 0
(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 (C) in the polyamide resin composition of the present invention needs to be 1 to 10 parts by mass with respect to 100 parts by mass of the polyamide resin (A), and 2 to 9 parts by mass. It is preferable that it is 3-8 mass parts. When the content of the swellable layered silicate (C) is less than 1 part by mass, the brightness and clearness of the resulting molded article are insufficient. On the other hand, when the content exceeds 10 parts by mass, the smoothness and clearness of the resulting molded article are lowered.

  There is no restriction | limiting in particular as the metallic pigment (D) which comprises the polyamide resin composition of this invention, A well-known thing can be used. As the metallic pigment (D), for example, one or a plurality of metals made of aluminum, iron, nickel, chromium, tin, zinc, indium, titanium, silicon, and copper, or a plurality of these metals or a group of these metals are used. And metal powder pigments made of any of the oxides, nitrides, sulfides or carbides of these alloys or a group of these metals. In addition, titanium-coated mica can also be used. Among these, aluminum, iron, oxides thereof, and titanium-coated mica are preferably used as the metallic pigment (D) in terms of the effect of improving the glossiness of the polyamide resin composition. Also good.

The average particle diameter of the metallic pigment (D) is preferably 1 to 100 μm, more preferably 2 to 80 μm, further preferably 3 to 60 μm, and particularly preferably 4 to 40 μm. The metallic pigment (D) having an average particle diameter of less than 1 μm has a low effect of improving the glossiness and is difficult to obtain. On the other hand, if the average particle size of the metallic pigment (D) exceeds 60 μm, handling when obtaining the polyamide resin composition becomes difficult, and melt mixing is performed while maintaining the average particle size of the raw material metallic pigment (D). It becomes difficult to do. Moreover, even if melt-mixing is possible, the resulting molded article of the polyamide resin composition has a high gloss, but tends to be inferior in design.
The average particle diameter of the metallic pigment (D) 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 (D) is preferably 1 to 30 μm, more preferably 1 to 20 μm, and further preferably 1 to 10 μm. The metallic pigment (D) having an average thickness of less than 1 μm is inferior in rigidity and it is difficult to maintain a shape when melt-mixed, and thus it is difficult to obtain a molded body having sufficient glossiness. On the other hand, the metallic pigment (D) 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 (D) 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 (D) 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 (D) can be obtained by dividing the value of the average particle diameter by the average thickness value.

  Content of the metallic pigment (D) in the polyamide resin composition of this invention needs to be 0.5-5 mass parts with respect to 100 mass parts of polyamide resins (A), and 0.7-4 mass Part is preferable, and 1 to 3 parts by mass is more preferable. When the content of the metallic pigment (D) is less than 0.5 parts by mass, the resulting molded product has insufficient luminance. Moreover, light resistance may be inferior. On the other hand, when the amount exceeds 5 parts by mass, the molded article has excessive luminance and the design properties are impaired.

  The polyamide resin composition of the present invention contains a colorant (E). The colorant (E) may be either a dye (e1) or a pigment (e2). The dye (e1) used in the present invention is not particularly limited, and known dyes can be used. Anthraquinone dyes, azo dyes, pyrazolone dyes, quinophthalone dyes, perinone dyes, quinoline dyes, methine Dyes, perylene dyes, coumarin dyes and the like. Said dye (e1) can be used 1 type or in combination of 2 or more types.

  Specific examples (color index) of anthraquinone dyes include Solvent Red 52, Solvent Red 111, Solvent Red 149, Solvent Red 150, Solvent Red 151, Solvent Red 168, Solvent Red 191, Solvent Red 207, Disperse Disperse Red 60, Disperse Violet 31, Solvent Blue 35, Solvent Blue 36, Solvent Blue 63, Solvent Blue 78, Solvent Blue 83, Solvent Blue 87, Solvent Blue 87, Solvent Blue 87, Solvent Blue 87, Solvent Blue 87, Solvent Blue 87, Solvent Blue 87 reen 20, Solvent Green 28, Disperse Violet 28, Solvent Violet 13, Solvent Violet 14, Solvent Violet 36, and the like.

  Specific examples (color index) of azo dyes include Solvent Yellow 14, Solvent Yellow 16, Solvent Yellow 21, Solvent Yellow 61, Solvent Yellow 81, Solvent Red 23, Solvent Red 24, Solvent Red 27, Solvent Red 27, Solent Red 27, Solent Red 27, Solent Red 27, Solent Red 27, Solent Red 27, Solvent Red Red 83, Solvent Red 84, Solvent Red 121, Solvent Red 132, Solvent Violet 21, Solvent Black 21, Solvent Black 23, Solvent Black 27, Solvent Black 37, Solvent Black 31, Solvent Black 31, Solvent Black 31 vent Orange 40, Solvent Orange 45, and the like.

  Specific examples (color index) of pyrazolone dyes include Solvent Yellow 93 and the like.

  Specific examples (color index) of the quinophthalone dye include Solvent Yellow 33, Solvent Yellow 114, Solvent Yellow 128, Solvent Yellow 129, Disperse Yellow 49, Disperse Yellow 54, Disperse Yellow 14 and the like.

  Specific examples (color index) of perinone-based dyes include Solvent Orange 60, Solvent Orange 78, Solvent Orange 90, Solvent Violet 29, Solvent Red 135, Solvent Red 162, Solvent Red 179, and the like.

  Specific examples (color index) of quinoline dyes include Solvent Yellow 33, Solvent Yellow 98, Solvent Yellow 157, Disperse Yellow 54, Disperse Yellow 160, and the like.

  Specific examples (color index) of methine dyes include Solvent Orange 80, Solvent Yellow 93, Disperse Yellow 201, and the like.

  Specific examples (color index) of the perylene dye include Solvent Green 3, Solvent Green 5, Solvent Orange 55, Vat Red 15, Vat Orange 7, F Orange 240, F Red 305, F Red 339, F Yellow 83, and the like.

  Specific examples (color index) of the coumarin-based dye include Solvent Yellow 160: 1.

  As the colorant (C) used in the present invention, anthraquinone dyes, azo dyes, perinone dyes, and methine dyes are preferably used. From the viewpoint of improving color development and suppressing fading, dark colors such as red are used. As the dyes, anthraquinone dyes, perinone dyes, and light-colored dyes such as yellow are preferably azo dyes and methine dyes.

  As the colorant (E) of the present invention, a pigment (e2) can be further combined with the dye (e1). The pigment (e2) used in the present invention is not particularly limited, and known pigments can be used. For example, azo pigments, anthraquinone pigments, phthalocyanine pigments, quinacridone pigments, perylene pigments, diketopyrrolo Organic pigments such as pyrrole pigments and dioxazine pigments, carbon blacks, titanium dioxide, ultramarine blue, cobalt blue, inorganic pigments such as petals, extender pigments such as calcium carbonate and barium sulfate can be used.

  In the present invention, when the pigment (e2) is used alone as the colorant (E), the color developability may be deteriorated particularly in coloring of red, yellow, etc. For example, the brightness is high and the saturation is low. There is a tendency that red is light red (pink) and yellow is light yellow. For example, when the color sample is red (Munsell value 5R 4/14), even if an attempt is made to color the pigment (e2) alone, the color tone is light red (Munsell value 4.3R 7.6). /6.8) or so, and highly accurate toning is not possible.

  On the other hand, by using a combination of the dye (e1) and the pigment (e2) as the colorant (E), color development can be improved and fading can be suppressed. The effect is particularly high in red and yellow colorants. For example, in the case of red, a perinone dye and a quinacridone pigment are preferably used, and in the case of yellow, a combination of a methine dye and an azo pigment is preferably used.

  Content of the coloring agent (E) in the polyamide resin composition of this invention is 0.05-0.8 mass part with respect to 100 mass parts of polyamide resins (A), and 0.08-0.7 mass part. It is preferable that it is 0.1-0.6 mass part. When the content of the colorant (E) is less than 0.05 parts by mass, the obtained molded article has excellent color developability. On the other hand, when it exceeds 0.8 mass part, the metallic feeling of a molded object will be impaired.

  In the polyamide resin composition of the present invention, coloring is performed using the colorant (E), but in order to match the desired color tone, it is possible to cope with each color tone by combining a plurality of dyes for each color. . Although the formulation differs depending on the color tone to be obtained, in order to express a vivid color tone, it is preferable to appropriately use a dye and a pigment as the colorant (E). When a dye and a pigment are used in combination as the colorant (E), it is preferable that (dye) / (pigment) = 95/5 to 50/50 (mass ratio), and 90/10 to 55/45 (mass ratio). And more preferably 85/15 to 60/40 (mass ratio).

The polyamide resin composition of the present invention can further contain a weathering agent (F). Examples of the weathering agent (F) that can be used include benzotriazole compounds, benzophenone compounds, triazine compounds, benzoate compounds, hindered amine compounds, salicylic acid phenyl ester compounds, cyanoacrylate compounds, and malonic ester compounds. Compounds, oxalic anilide compounds, and the like. Of these, triazine compounds, malonic ester compounds, and oxalic anilide compounds are preferably used. These may be used alone or in combination of two or more.
In particular, the hindered amine-based compound has a high effect of scavenging radicals and suppressing photooxidation of the polyamide resin composition, so that the effect of suppressing ultraviolet absorption in combination with another weathering agent (F) is enhanced.

  The content of the weathering agent (F) is preferably 0.1 to 2 parts by mass, and more preferably 0.2 to 1.8 parts by mass with respect to 100 parts by mass of the polyamide resin (A). When the content of the weathering agent (F) is less than 0.1 parts by mass, the effect of suppressing ultraviolet absorption becomes insufficient, and the resulting molded article may change in color tone or decrease in surface gloss. When the content of the weathering agent (F) exceeds 2 parts by mass, the effect of suppressing ultraviolet absorption is no longer saturated and uneconomical, and it is obtained by bleeding out on the surface of the molded body when the molded body is used. The brightness and clearness of the molded product may be impaired. Moreover, a color tone change may be accompanied.

  When the hindered amine compound and the above-mentioned other weathering agent (F) are used in combination as the weathering agent (F), the total amount to be blended is 0.1 to 2 with respect to 100 parts by mass of the polyamide resin (A). It is preferable that it is a mass part. The blending ratio of the hindered amine compound and the other weathering agent (F) is preferably hindered amine compound / other weathering agent (F) = 30/70 to 70/30 (mass ratio), 40/60 to 60 / 40 (mass ratio) is more preferable. When a hindered amine compound is used alone as the weathering agent (F), it may bleed out to the surface of the hindered amine compound molded article even at the predetermined content.

  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. Moreover, in order to assist flame retardancy in particular, a condensed phosphate ester, polyphosphoric acid, a nitrogen compound flame retardant, or 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 (C), and the metallic pigment (D).
In the present invention, the polyamide resin (A) and the swellable layered silicate (C) obtained by polymerizing the monomer component constituting the polyamide resin (A) in the presence of the swellable layered silicate (C). It is preferable to produce a polyamide resin composition by melt-mixing the mixture and the metallic pigment (D) using a mixture of
In the presence of the swellable layered silicate (C), the monomer component constituting the polyamide resin (A) is subjected to a polymerization reaction to uniformly disperse the swellable layered silicate (C) 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 (C) It is preferable to produce a polyamide resin composition by using a mixture obtained by carrying out the copolymerization reaction of and melting and mixing the mixture and the metallic pigment (D).

  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 (C), a mixture of the resulting polymer and the swellable layered silicate (C) and another polymer (or another polymer and the swellable layered silicate (C )) And the metallic pigment (D) are preferably melt mixed to produce a polyamide resin composition. The aminocarboxylic acid that undergoes a polymerization reaction in the presence of the swellable layered silicate (C) has a high effect of uniformly dispersing the swellable layered silicate (C), and therefore 6-aminocaproic acid or ε-caprolactam 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 need to be 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, especially in the present invention, it is difficult to uniformly orient the contained metallic pigment (D) when obtaining a molded product, so that the luminance is partially impaired or the 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 for polymerizing aminocarboxylic acid (lactam) in the presence of the swellable layered silicate (C), after the swellable layered silicate (C) and aminocarboxylic acid (lactam) are charged into 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. When ε-caprolactam is used, it is preferable to polymerize at a temperature of 250 to 280 ° C., a pressure of 0.5 to 2 MPa, and a range of 3 to 5 hours.
Moreover, in order to remove the 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 (C) and the metallic pigment (D), a known melt-kneading extruder can be used.
In order to suppress crushing or breakage due to kneading of the metallic pigment (D) as much as possible, the screw is preferably used uniaxially rather than biaxially.
As a method for supplying the metallic pigment (D) to the melt-kneading extruder, a mixture of the metallic pigment (D) and the mixture may be added all at once from the main hopper, but the metallic pigment (D) may be crushed or In order to suppress breakage as much as possible, it is preferable to supply the metallic pigment (D) from the middle of the extruder with a side feeder, and it is more preferable to supply it as downstream as possible.
The mixture and the metallic pigment (D) 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 (D) may be directly supplied to an injection molding machine, or may be melt-kneaded in the injection molding machine to perform injection molding.
Since the metallic pigment (D) 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 (D) 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, the moldability may become unstable, for example, a short may occur in the molded body, or the 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 article of the present invention, particularly a molded article 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 well balanced. By setting, the luminance can be further improved. 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 (C) in a polyamide resin composition, and a metallic pigment (D). 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 (D) is disturbed and the luminance tends to decrease. Therefore, the injection speed is preferably from low to medium.

  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. Moreover, since it is excellent in light resistance, heat discoloration resistance, and heat-and-moisture resistance, it is suitable for long-term use such as automobile parts.

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

1. Evaluation method

(1) Surface glossiness Based on JIS Z8741, the surface glossiness of the plate-shaped molded body was measured using a gloss meter (Gloss Meter VG7000, manufactured by Nippon Denshoku Co., Ltd.). The glossiness is preferably 90% or more practically.

(2) Luminance Observation was performed from the direction of an angle of 45 ° with the normal line of the plate-shaped molded body under a fluorescent lamp having an illuminance of 1000 Lx, and the luminance was subjected to sensory evaluation with the naked eye.
4: Although it has a glare feeling, it is slightly excessive.
3: It has a moderate glare feeling.
2: The metal-specific shine and clearness are insufficient.
1: Does not have metal-specific shine.

(3) Color Tone and Color Tone Judgment A color sample that is red (Munsell value 5R 4/14) or yellow (Munsell value 5Y 8/13) was visually compared to confirm the color tone after toning. Those that could be toned to the same degree as the predetermined color tone were marked with ◯, and those that could not be toned were marked with ×.

(4) Moisture and heat resistance The plate-shaped molded body was subjected to a heat treatment for 240 hours under the conditions of a temperature of 50 ° C. and a humidity of 95% RH using a thermo-hygrostat (FH14C type manufactured by ETAC). The plate after the test was observed and the presence or absence of bleed out was evaluated according to the following criteria. It is preferable that no bleed out occurs after the heat and humidity resistance test.
A: No bleed out.
○: Precipitation of oligomers mainly caused by polyamide 6 There are no practical problems.
Δ: Precipitation of weathering agent or the like can be confirmed.

(5) Light resistance Using a xenon weather meter (C400i type manufactured by Atlas Co., Ltd.), the plate-shaped molded body was subjected to conditions of a black panel temperature of 89 ° C., a humidity of 50% RH, and a radiation exposure of 150 MJ / m ² (no rain). An irradiation test was conducted. Here, based on JIS Z8722, the color difference ΔE of the plate-shaped molded body before and after the light resistance test was measured and used as a light resistance judgment index.
Practically, the color difference ΔE is preferably 18 or less, and more preferably 15 or less.

(6) Heat-resistant discoloration The plate-shaped molded body was subjected to a heat treatment for 500 hours at a temperature of 105 ° C. using a hot air dryer (PHH-101 type manufactured by ESPEC). Here, based on JIS Z8722, the color difference ΔE of the plate-like molded body after the heat discoloration test was measured and used as a judgment index for heat discoloration. In practical terms, the color difference ΔE is preferably 4 or less.

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

(2) Aliphatic polyamide resin P-2: Polyamide 12 (“AMN O TLD” manufactured by Arkema), relative viscosity 2.3
P-3: Polyamide 6 (“A1030BRL” manufactured by Unitika), relative viscosity 2.5

(3) Aromatic polyamide resin B-1: isophthalic acid / terephthalic acid / 1,6-hexanediamine polycondensate (“X21” manufactured by DSM), glass transition temperature 138 ° C., relative viscosity: 2.0, Heat of fusion 0.1 cal / g

(4) Swellable layered silicate / C-1: Swellable fluoromica (“ME-100” manufactured by Co-op Chemical)

(5) Metallic pigment D-1: Aluminum powder masterbatch (“NME U20TZ” manufactured by Toyo Aluminum Co., Ltd.) Aluminum powder (average particle diameter 20 μm, average thickness 4 μm) 70% by mass kneaded with polyethylene

(6) Colorant (a) Red dye / perinone dye: Solvent Red 135 (“Macrolex Red EG” manufactured by LANXESS)
(B) Red pigment / dimethylquinacridone pigment (“Fastogen Super Magenta RG” manufactured by DIC), primary particle size 134 nm
(C) Yellow dye / methine dye: Disperse Yellow 201 (“Macrolex Yellow 6G” manufactured by LANXESS)
(D) Yellow pigment / disazo pigment: (Pigment Yellow 180), primary particle diameter 50 nm

(7) Weathering agent / UVA-1: Benzotriazole ultraviolet absorber (“Tinuvin 234” manufactured by BASF Japan)
UVA-2: triazine ultraviolet absorber ("Tinuvin 1577" manufactured by BASF Japan)
-HALS: hindered amine light stabilizer ("Tinvin 622" manufactured by BASF Japan)

Example 1
After charging 0.4 parts by mass of phosphorous acid, 5.25 parts by mass of swellable layered silicate (C-1) and 5 parts by mass of water with respect to 100 parts by mass of ε-caprolactam and stirring at 80 ° C. for 1 hour The polyamide resin is stirred for 1 hour at 260 ° C. and 0.7 MPa, then stirred at 260 ° C. for 1 hour at normal pressure, polymerized, and containing 4.2% by mass of the swellable layered silicate (C-1) (P-1) was obtained.
88.74 parts by mass of (P-1) as an aliphatic polyamide resin, 15 parts by mass of an aromatic polyamide resin (B-1), 0.3 parts by mass of a metallic pigment (D-1), and 0 red dye as a colorant .3 parts by mass 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.
Using the obtained polyamide resin composition, with an injection molding machine (EC-100II type manufactured by Toshiba Machine Co., Ltd.), the resin temperature is 260 ° C., the mold temperature is 100 ° C., the holding pressure is 30 MPa, the injection speed is 100 mm / s, and the injection pressure. Injection molding was performed under the conditions of 100 MPa and a cooling time of 10 seconds to obtain a plate-like molded body having a length of 90 mm × width of 50 mm × thickness of 2 mm. A mold having one side gate at the center in the short side direction was used. Various evaluation was performed about the obtained plate-shaped molded object. The results are shown in Table 1.

Examples 2-19, Comparative Examples 1-3
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 Table 1 or 2, and injection molding was further performed. Various evaluation was performed using the obtained plate-shaped molded object. The results are shown in Tables 1 and 2.

  In Examples 1-19, the polyamide resin composition which was excellent in metallic coloring property and the brightness | luminance, and in which fading was suppressed was obtained. In particular, Examples 2, 3, 5-11, 13, and 15 were excellent in light resistance and heat discoloration and improved in fading. Further, in Examples 5 to 9, 11, and 15, the heat and humidity resistance was also improved.

  In Comparative Example 1, since the aromatic polyamide resin was not contained, the light resistance was inferior.

  In Comparative Example 2, since the metallic pigment was not contained, the luminance was inferior.

In Comparative Example 3, since the swellable layered silicate was not contained, the brightness and clearness were inferior.

Claims (6)

  For a total of 100 parts by mass of 60 to 95 parts by mass of the aliphatic polyamide resin (A) and 5 to 40 parts by mass of the aromatic polyamide resin (B), 1 to 10 parts by mass of the swellable layered silicate (C), metallic pigment ( D) A polyamide resin composition containing 0.5 to 5 parts by mass and a colorant (E) 0.05 to 0.8 parts by mass.   The polyamide resin composition according to claim 1, wherein the aromatic polyamide resin (B) is an amorphous polyamide.   3. The polyamide resin according to claim 1, comprising a dye (e1) and a pigment (e2) as the colorant (E), wherein (e1) / (e2) = 80/20 to 50/50 (mass ratio). Composition.   The polyamide resin composition according to any one of claims 1 to 3, wherein the colorant (E) is a red or yellow colorant.   Furthermore, the polyamide resin composition in any one of Claims 1-4 containing a weathering agent (F).   The molded object formed by shape | molding the polyamide resin composition in any one of Claims 1-5.