JP2011057977A - Polyamide resin composition excellent in weatherability and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyamide resin composition excellent in weatherability. <P>SOLUTION: The polyamide resin composition comprises (A) 100 pts.wt. of a polyamide resin, (B) 0.1-30 pts.wt. of carbon black, and (C) 0-200 pts.wt. of an inorganic filler. In the carbon black, an average primary particle size is 10-25 nm, and a DBP oil absorption is 70 ml/100g or more. Preferably, the carbon black (B) has the average primary particle size of 14-20 nm, and the DBP oil absorption of 70-150 ml/100g. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a polyamide resin composition, and in particular, a resin composition excellent in weather resistance, that is, a resin composition that gives a molded article having excellent appearance with little change in color tone and surface roughness even in an outdoor exposure environment and its production It is about the method.

  Polyamide resins have good mechanical properties, moldability, chemical resistance, and the like, and are widely used in automobiles, machine parts, building materials, housing equipment-related parts, and the like. However, polyamide resins are susceptible to oxidative degradation, which causes undesirable degradation phenomena such as a decrease in mechanical strength, surface cracking, and change in color tone. Since this oxidative degradation is accelerated by heat and light, there is a limit to the use of polyamide resin under outdoor exposure. In order to prevent such a deterioration phenomenon, it has been conventionally proposed to add various stabilizers. For example, blending carbon black with a polyamide resin is described (Patent Documents 1 and 2).

  Carbon black is an effective means of preventing deterioration of polyamide resin, but the conventional one still has satisfactory performance for applications such as automobile wipers that are constantly exposed to sunlight. Absent.

JP 2003-105196 A JP 2003-105198 A

  The present invention intends to provide a polyamide resin composition which is excellent in moldability, thermal properties, mechanical properties and surface appearance, which are characteristic of polyamide resin, and excellent in weather resistance under severe outdoor exposure. is there.

As a result of studying carbon black to be blended with a polyamide resin, the present inventor has found that a specific carbon black gives a resin composition particularly excellent in weather resistance, and has completed the present invention.
That is, the first gist of the present invention is:
(1) A resin composition comprising (B) 0.1 to 30 parts by weight of carbon black and (C) 0 to 200 parts by weight of an inorganic filler with respect to 100 parts by weight of (A) polyamide resin, The carbon black has an average primary particle diameter of 10 to 25 nm and a DBP oil absorption of 70 ml / 100 g or more.
The second gist of the present invention is as follows:
(2) A master batch of carbon black in which (B) carbon black is melt-kneaded in part of (A) polyamide resin is manufactured in advance, and the remaining (A) polyamide resin and (C) inorganic filler are melted into this master batch. The manufacturing method of the polyamide resin composition as described in said (1) formed by kneading | mixing.

  Since the polyamide resin composition according to the present invention is excellent in weather resistance, particularly weather resistance under outdoor exposure that is strongly affected by sunlight, it is used for vehicle parts such as wipers, bumpers, and fenders, and for building and housing parts. Especially, it can be used suitably for exterior parts for vehicles.

(A) Polyamide resin:
The polyamide resin in the present invention is not particularly limited as long as it is a known polyamide resin, that is, a polymer containing an amide bond (—NHCO—) in the main chain and capable of being melted by heating. Specifically, various types of polyamide resins such as lactam polycondensate, polycondensate of diamine and dicarboxylic acid, polycondensate of ω-aminocarboxylic acid, or copolymerized polyamide resins and blends thereof, etc. It is. Two or more of the above lactams, diamines, dicarboxylic acids and ω-aminocarboxylic acids may be used in combination.

Examples of the lactam include ε-caprolactam and ω-laurolactam.
Examples of diamines include tetramethylene diamine, pentamethylene diamine, hexamethylene diamine, 2-methylpentamethylene diamine, undecamethylene diamine, dodecamethylene diamine, (2,2,4- or 2,4,4-) trimethylhexamethylene. Diamine, 5-methylnonamethylenediamine, metaxylylenediamine, paraxylylenediamine, 1,3-bis (aminomethyl) cyclohexane, 1,4-bis (aminomethyl) cyclohexane, 1-amino-3-aminomethyl- 3,5,5-trimethylcyclohexane, bis (4-aminocyclohexyl) methane, bis (3-methyl-4-aminocyclohexyl) methane, 2,2-bis (4-aminocyclohexyl) propane, bis (aminopropyl) piperazine Aminoethyl pipette Aliphatic, such as gin, alicyclic, diamines aromatic.

  Examples of dicarboxylic acids include adipic acid, speric acid, azelaic acid, sebacic acid, dodecanedioic acid, terephthalic acid, isophthalic acid, 2-chloroterephthalic acid, 2-methylterephthalic acid, 5-methylisophthalic acid, 5-sodium sulfoisophthalic acid. Aliphatic, alicyclic and aromatic dicarboxylic acids such as acid, hexahydroterephthalic acid, hexahydroisophthalic acid and the like can be mentioned.

  Examples of the ω-aminocarboxylic acid include amino acids such as 6-aminocaproic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, and paraaminomethylbenzoic acid.

  As a raw material of the polyamide resin as described above, a compound having 5 to 10 carbon atoms is preferable. If the number of carbon atoms is less than 5, the water absorption increases due to the increase of the amide group concentration, and the dimensional change and physical property decrease due to water absorption are large. . Specifically, ε-caprolactam as a lactam, pentamethylenediamine, hexamethylenediamine, metaxylylenediamine, paraxylylenediamine as a diamine, and adipic acid, terephthalic acid, and isophthalic acid as dicarboxylic acids are easily available. It is more preferable because it is advantageous in terms of price.

  The polyamide resin in the present invention is a salt obtained by neutralizing diamine and dicarboxylic acid in an aqueous solution under pressure and high temperature, and the above lactam and ω-aminocarboxylic acid under pressure and high temperature. The oligomerization reaction can be advanced by polycondensation, and then the polymerization can proceed to an appropriate melt viscosity by reducing the pressure.

  Specific examples of the polyamide resin include, for example, polytetramethylene adipamide (polyamide 46), polycaprolactam (polyamide 6), polyhexamethylene adipamide (polyamide 66), polyhexamethylene sebacamide (polyamide 610), Aliphatic polyamide resins such as polyhexamethylene dodecamide (polyamide 612), polyundecanolactam (polyamide 11), polydodecanolactam (polyamide 12), polyamide 6/66, and polyhexamethylene terephthalamide (polyamide 6T) , Polyhexamethylene isophthalamide (polyamide 6I), polymetaxylylene adipamide (polyamide MXD6), a mixed resin of metaxylylene diamine and paraxylylene diamine, and a polyamide resin that is a polycondensate of adipic acid (Polymer) Amide MP6), polymetaxylylene decanamide, polyamide 9T, polyamide 9MT, polyamide 66 / 6T, polyamide 6 / 6T, polyamide 6I / 6T, polyamide 66 / 6T / 6I, terephthalic acid and / or isophthalic acid and adipic acid and meta And semi-aromatic polyamide resins such as polycondensates with xylylenediamine. As the aliphatic polyamide resin, polyamide 6, polyamide 66, and polyamide 6/66 are preferable, and polyamide 6 or polyamide 66 is more preferable from the viewpoint of heat resistance and compatibility when used in combination with a semi-aromatic polyamide resin. The semi-aromatic polyamide resin is preferably a polycondensate of xylylenediamine such as polyamide MXD6 or polyamide MP6 and an α, ω-linear aliphatic dibasic acid from the viewpoint of heat resistance and rigidity.

  As the xylylenediamine which is a raw material of the polycondensate of xylylenediamine and α, ω-linear aliphatic dibasic acid, metaxylylenediamine or mixed xylylenediamine of paraxylylenediamine and metaxylylenediamine Can be suitably used. When paraxylylenediamine and metaxylylenediamine are used in combination, it is preferable to use paraxylylenediamine and metaxylylenediamine in a ratio of 10 to 45/90 to 45 (mol%), 20 to 50/80. It is more preferable to use it at a ratio of ˜50 (mol%). If the amount of paraxylylenediamine in the mixed xylylenediamine is less than 10 mol%, a necessary and sufficient crystallization rate may not be obtained. On the other hand, if it exceeds 45 mol%, the melting point of the obtained polyamide resin becomes high, and polymerization occurs. At times, there is a possibility of causing inconvenience during the molding process.

  The α, ω-linear aliphatic dibasic acid that is a raw material of the polycondensate of xylylenediamine and α, ω-linear aliphatic dibasic acid includes α, ω-direct carbon atoms of 6 to 20 carbon atoms. A chain aliphatic dibasic acid, for example, adipic acid, sebacic acid, suberic acid, dodecanedioic acid, eicodioic acid and the like can be preferably used. Among these, adipic acid is particularly preferable in consideration of a balance between moldability and molded product performance.

The semi-aromatic polyamide preferably has a ratio of terminal amino group concentration to terminal carboxyl group concentration ([NH ₂ / COOH]) of 0.6 or less, and more preferably 0.48 or less. When this ratio is larger than 0.6, the weather resistance is inferior and tends to be discolored during use. The terminal amino group concentration can be measured by dissolving 1 g of polyamide in a phenol / methanol mixed solution and titrating with 0.02N hydrochloric acid. The terminal carboxyl group concentration can be measured by dissolving 1 g of polyamide in benzyl alcohol and titrating with 0.05N sodium hydroxide solution.

  The relative viscosity of the polyamide resin is a relative viscosity measured in 98% sulfuric acid at a concentration of 1% by weight and a temperature of 25 ° C., and is usually 1.6 to 4, preferably 2 to 3.8. If the relative viscosity is less than 1.6, the resulting resin composition tends to be brittle. Conversely, if the relative viscosity exceeds 4, the fluidity at the time of molding the polyamide resin composition may be insufficient.

  In the present invention, it is preferable to use an aliphatic polyamide resin and a semi-aromatic polyamide resin in combination. When used in combination, the aliphatic polyamide resin is preferably 1 to 40% by weight, more preferably 3 to 30% by weight, particularly preferably 5 to 20% by weight, and preferably the semiaromatic polyamide resin 99 to 60% by weight, and more. It is preferably used in a proportion of 97 to 70% by weight, particularly preferably 95 to 80% by weight. If the ratio of the aliphatic polyamide resin in the polyamide resin is less than 1% by weight, it is difficult to obtain a necessary and sufficient crystallization speed, and the molding cycle tends to be long, which is not preferable. When the ratio of the aliphatic polyamide resin exceeds 40% by weight, the rigidity and the dimensional stability due to moisture absorption may decrease, which is not preferable.

The polyamide resin composition of the present invention is usually 50 parts by weight or less, preferably 30 parts by weight or less, more preferably 20 parts by weight with respect to 100 parts by weight of the polyamide resin, as long as the effects of the present invention are not impaired. Other resins can also be contained in an amount of less than or equal to parts. Examples include polyphenylene ether resin, polyester resin, polyphenylene sulfide resin, liquid crystal polyester resin, polycarbonate resin, polyacetal resin, polyacrylonitrile resin, acrylic resin, polyethylene resin, polypropylene resin, ethylene-propylene copolymer, ethylene-butene. Hydrogenated product of copolymer, ethylene-methacrylate copolymer, olefin resin such as ethylene-vinyl acetate copolymer, polystyrene, high-impact polystyrene, styrene-acrylonitrile copolymer, styrene-butene-styrene copolymer (SEBS), styrene resins such as hydrogenated styrene-isoprene-styrene copolymer (SEPS), and the like, and further modified with glycidyl methacrylate or maleic anhydride It can be used thermoplastic resins such as those were.
Moreover, you may use thermosetting resins, such as an epoxy resin, a melamine resin, and a silicone resin, as another resin.

(B) Carbon black:
In the present invention, carbon black having an average primary particle diameter of 10 to 25 nm and a DBP oil absorption of 70 ml / 100 g or more is used. The average primary particle size of carbon black is preferably 12 to 23 nm, more preferably 14 to 20 nm, and the DBP oil absorption is preferably 70 to 150 ml / 100 g. Even if the average primary particle diameter is in the range of 10 to 25 nm, a resin composition using a small DBP oil absorption amount, or a resin composition using an average primary particle diameter outside the range of 10 to 25 nm even if the DBP oil absorption amount is large. The color tone changes greatly when exposed to sunlight, and the surface of the molded product is extremely rough.
In the present invention, the average primary particle size is a value measured by the following method.
An aggregate enlarged image is obtained by the procedure described in the ASTM D3849 standard (standard test method of carbon black-morphological characterization by electron microscopy), and 3,000 particle sizes as unit constituent particles are obtained from the aggregate image. Measure and obtain the average value to obtain the average primary particle size.
Further, the DBP oil absorption amount of carbon black is a value obtained by measurement according to JIS K6217 standard.

  (B) Carbon black content is 0.1-30 weight part with respect to 100 weight part of (A) polyamide resin, Preferably it is 0.5-25 weight part, More preferably, it is 1-20 weight part. If the content is less than 0.1 parts by weight, the desired weather resistance is not exhibited. When the content exceeds 30 parts by weight, rigidity and other mechanical properties are deteriorated.

(C) Inorganic filler:
In the present invention, it is preferable to blend an inorganic filler mainly for the purpose of reinforcing the resin composition and improving rigidity, heat resistance, dimensional stability and the like. There is no restriction | limiting in particular in the shape etc. of an inorganic filler, Any of fiber shape, plate shape, a granular form, and needle shape may be sufficient. Specific examples thereof include, for example, glass fiber, glass flake, glass bead, milled fiber, alumina fiber, carbon fiber, titanium oxide, magnesium oxide, calcium carbonate, barium sulfate, boron nitride, potassium titanate whisker, silica, mica, Examples include talc and wollastonite. Among these, fibrous materials are preferable, and glass fibers are particularly preferable.

  The glass fiber preferably used in the present invention preferably has an average diameter of 20 μm or less, and further 1 to 15 μm further enhances the balance of physical properties (heat resistance rigidity, impact strength) and further reduces the molding warp. This is preferable in terms of reduction.

  The length of the glass fiber is not specified and can be selected from a long fiber type (roving), a short fiber type (chopped strand), or the like. In this case, the number of focusing is preferably about 100 to 5000. If the average length of the glass fiber in the resin composition after kneading the resin composition is 0.1 mm or more, so-called milled fiber or a pulverized product of strands called glass powder may be used. A fiber sliver may also be used. The composition of the raw material glass is preferably non-alkali, and examples thereof include E glass, C glass, and S glass. In the present invention, E glass is preferably used.

  The glass fiber is preferably surface-treated with a silane coupling agent such as γ-methacryloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane, etc. The adhesion amount is usually 0.01 to 1% by weight of the glass fiber weight. Furthermore, if necessary, a lubricant such as a fatty acid amide compound, silicone oil, an antistatic agent such as a quaternary ammonium salt, a resin having a film forming ability such as an epoxy resin or a urethane resin, a resin having a film forming ability and a heat. What was surface-treated with a mixture of a stabilizer, a flame retardant, etc. can also be used.

  (C) Content of an inorganic filler is 200 weight part or less with respect to 100 weight of (A) polyamide resin, Preferably it is 30-180 weight part, More preferably, it is 50-150 weight part. When content of an inorganic filler exceeds 200 weight part, it exists in the tendency for fluidity | liquidity and a molded article external appearance to fall easily.

The polyamide resin composition of the present invention may contain additives in addition to the above-described essential components as long as the effectiveness of the present invention is not impaired. Specifically, it is preferable to add a nucleating agent in order to increase the crystallization rate and improve the moldability.
Examples of the nucleating agent include inorganic nucleating agents such as talc and boron nitride, but organic nucleating agents may also be used. The blending amount of the nucleating agent is 0.001 to 6 parts by weight, preferably 0.02 to 2 parts by weight, more preferably 0.002 parts by weight in the case of the organic nucleating agent or boron nitride with respect to 100 parts by weight of the (A) polyamide resin. 05 to 1 part by weight. If the amount is too small, the expected nucleating agent effect may not be obtained, and the releasability may decrease. If the amount is too large, impact resistance and surface appearance tend to decrease. When using talc, it is 0.1-8 weight part with respect to 100 weight part of (A) polyamide resin, Preferably it is 0.3-4 weight part. In the case of an inorganic nucleating agent other than talc and boron nitride, it is 0.3 to 8 parts by weight, preferably 0.5 to 4 parts by weight, based on 100 parts by weight of (A) polyamide resin. If the amount is too small, the nucleating agent effect cannot be obtained. In the present invention, talc or boron nitride is preferably blended from the viewpoint of mechanical properties such as impact resistance, tensile elongation and bending deflection.

  As the talc, those having a number average particle diameter of 2 μm or less are preferable. As boron nitride, the number average particle diameter is usually 10 μm or less, preferably 0.005 to 5 μm, more preferably 0.01 to 3 μm. The number average particle diameters of talc and boron nitride are usually values obtained by measurement using a laser diffraction / scattering particle size distribution meter.

In the present invention, it is also preferable to add a release agent in order to improve the release property at the time of molding. The release agent also has an effect of improving slidability.
Examples of the release agent include long chain aliphatic carboxylic acids having 14 or more carbon atoms such as stearic acid and palmitic acid and derivatives thereof (for example, esters, alkali metal salts, alkaline earth metal salts, amides). Etc.), higher aliphatic alcohols having 14 or more carbon atoms such as stearyl alcohol and derivatives thereof, amines and derivatives thereof having 14 or more carbon atoms such as stearylamine, waxes such as low molecular weight polyethylene wax and paraffin wax, silicones Examples thereof include oil and silicone gum. Among these, an aliphatic carboxylic acid derivative is preferable from the viewpoint that there is little decrease in paintability.

  Examples of the aliphatic carboxylic acid derivatives include carboxylic acid esters, carboxylic acid metal salts (alkali metal salts, alkaline earth metal salts), carboxylic acid amides, and the like.

  Examples of the aliphatic carboxylic acid esters include esters of long-chain aliphatic carboxylic acids having 14 or more carbon atoms such as palmitic acid, stearic acid, and montanic acid.

  The carboxylic acid metal salt is an alkali metal salt or alkaline earth metal salt of a long-chain aliphatic carboxylic acid having 14 or more carbon atoms. For example, calcium stearate, calcium montanate, sodium montanate, zinc stearate, stearin Examples thereof include aluminum oxide, sodium stearate, and lithium stearate.

The carboxylic acid amide is a compound or bisamide compound obtained by a dehydration reaction between a mixture of an aliphatic monocarboxylic acid and a polybasic acid and a diamine.
The aliphatic monocarboxylic acid is preferably a saturated aliphatic monocarboxylic acid having 14 or more carbon atoms and a hydroxycarboxylic acid, and examples thereof include palmitic acid, stearic acid, behenic acid, montanic acid, 12-hydroxystearic acid and the like. .
The polybasic acid is a dibasic acid or higher carboxylic acid, for example, an aliphatic dicarboxylic acid such as malonic acid, succinic acid, adipic acid, sebacic acid, pimelic acid, azelaic acid, or aromatic such as phthalic acid or terephthalic acid. Examples thereof include dicarboxylic acids and alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid and cyclohexylsuccinic acid.
Examples of the diamine include ethylenediamine, 1,3-diaminopropane, 1,4-diaminobutane, hexamethylenediamine, metaxylylenediamine, tolylenediamine, paraxylylenediamine, phenylenediamine, and isophoronediamine.
The softening point of the carboxylic acid amide wax in the present invention can be arbitrarily adjusted by changing the mixing ratio of the polybasic acid with respect to the aliphatic monocarboxylic acid used for the production thereof. The mixing ratio of the polybasic acid is preferably in the range of 0.18 to 1 mol with respect to 2 mol of the aliphatic monocarboxylic acid. The amount of the diamine compound used is preferably in the range of 1.5 to 2 mol with respect to 2 mol of the aliphatic monocarboxylic acid, and varies according to the amount of polybasic acid to be used.

  Examples of bisamide compounds include diamine and carboxylic acid compounds such as N, N′-methylenebisstearic acid amide and N, N′-ethylene bisstearic acid amide, or N, N′-dioctadecyl terephthalic acid amide. And dioctadecyl dibasic acid amide.

  The content of the release agent is usually 0.03 to 3 parts by weight, preferably 0.03 to 2 parts by weight, more preferably 0.05 to 1.3 parts by weight, based on 100 parts by weight of the (A) polyamide resin. It is. When the content of the release agent is less than 0.03 parts by weight, the effect of improving the mold release and moldability may be insufficient. When the content exceeds 3 parts by weight, heat resistance, mold contamination, and plasticization Problems such as defects tend to occur.

  In addition to the above, various additives commonly used in polyamide resin compositions, for example, copper halides common to polyamide resins (for example, copper iodide, copper chloride, copper bromide) and halogenated Stabilizers such as metal (for example, potassium iodide, potassium bromide, etc.), organic (for example, hindered phenol, phosphite, etc.), flame retardants, pigments, dyes and the like can be appropriately added.

  The polyamide resin composition of the present invention can be produced according to a conventional method for producing a resin composition. For example, polyamide resin, carbon black and other various additives contained as necessary are mixed well with a mixing apparatus such as a tumbler mixer, a Henshur mixer, a ribbon blender, etc., and the resulting mixture is, for example, bent It may be supplied to a melt kneader such as a single-screw or twin-screw extruder or a Banbury mixer, and melted and kneaded into pellets. In addition, a carbon black masterbatch in which carbon black is melt-kneaded in part or all of the polyamide resin in advance is manufactured, and then the remaining components may be melt-kneaded or dry blended therein. When a fibrous inorganic filler such as glass fiber is contained, side feed is preferably performed from the middle of the melt-kneader so that the fibrous inorganic reinforcing material in the resulting composition is not crushed. Moreover, the method of carrying out pellet blend of 2 or more types of melt-kneaded materials from which a composition differs may be sufficient.

  In the present invention, a carbon black master batch is prepared by previously melting and kneading carbon black in a part of the polyamide resin, and then the remaining polyamide resin and other components contained as necessary are melt kneaded. Is preferred. By adopting such a method, the dispersibility of carbon black is further improved, and the weather resistance tends to be further improved.

  In the production of a carbon black masterbatch, it is usually preferable to melt and knead the entire amount of carbon black used in the production of the resin composition of the present invention with a polyamide resin. The total amount is not necessarily limited. Usually, it is preferable that the carbon black content in the carbon black masterbatch is 10 to 40% by weight, preferably 15 to 35% by weight, and melt-kneaded.

  Moreover, in this invention, when using together an aliphatic polyamide resin and a semi-aromatic polyamide resin as a polyamide resin, it is preferable to use a semi-aromatic polyamide resin as a polyamide resin used for manufacture of a carbon black masterbatch. Semi-aromatic polyamide resin is generally said to be inferior in weather resistance compared to aliphatic polyamide resin. However, in the present invention, carbon black is well melt-kneaded with semi-aromatic polyamide resin in advance. Since black shields the semi-aromatic polyamide resin from light and the light shielding effect by carbon black functions more effectively, the weather resistance of the finally obtained polyamide resin composition can be further improved. The expression of this effect is considered to be because both carbon black and semi-aromatic polyamide resin have a carbon 6-membered ring structure. When both of them having a carbon 6-membered ring structure are melt-kneaded, the carbon black is strongly coordinated to the semi-aromatic polyamide resin due to the mutual affinity of the ring structures. When such a composition is obtained as a master batch, and then this master batch is melt-kneaded with the remaining aliphatic polyamide resin or a mixed resin of an aliphatic polyamide resin and a semi-aromatic polyamide resin, the carbon black becomes a semi-batch in the polyamide resin. It will be present in the vicinity of the aromatic polyamide resin, and it is considered that the semi-aromatic polyamide resin is protected from light and the weather resistance is further improved.

  A master batch of carbon black and semi-aromatic polyamide resin can be obtained by an ordinary melt-kneading method. That is, a predetermined amount of carbon black and semi-aromatic polyamide resin are mixed well by a mixing device such as a tumbler mixer, a Henshur mixer, or a ribbon blender. Next, melt kneading is performed using a melt kneader such as a single-screw or twin-screw extruder with a vent. After melt-kneading, it is extruded into a strand shape and pelletized through a cooling and cutting process. Thus, what is necessary is just to obtain the masterbatch which contains carbon black in high concentration. In addition, the masterbatch, the remaining polyamide resin, and other components contained as necessary may be kneaded by the same kneading method as in the production of the masterbatch.

  The polyamide resin composition thus obtained is a molding method generally employed for thermoplastic resins, that is, an injection molding method, an injection compression molding method, a hollow molding method, an extrusion molding method, a sheet molding method, a thermoforming method. Various molded products can be obtained by a rotational molding method, a lamination molding method, a press molding method, or the like. Among these, it is preferable to employ an injection molding method from the viewpoint of fluidity.

  Examples The present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples. The materials and evaluation methods used in the examples are shown below.

<Material>
(A) Polyamide resin:
Semi-aromatic polyamide resin; polyamide MXD6 (polycondensation product of metaxylylenediamine and adipic acid), “polyamide MXD6 # 6000” manufactured by Mitsubishi Gas Chemical Co., Inc., relative viscosity 2.14 (in 98% sulfuric acid, concentration 1) (Weight%, value obtained by measuring at a temperature of 25 ° C.)
Aliphatic polyamide resin; polyamide 66 (polycondensate of hexamethylenediamine and adipic acid), “Amilan CM3001N” manufactured by Toray Industries, Inc., relative viscosity 2.95 (measured in the same manner as in (1) above)

(B) Carbon black:
Carbon black-1; “# 950” manufactured by Mitsubishi Chemical Corporation, average primary particle size 16 nm, DBP oil absorption 74 ml / 100 g
Carbon black-2; “# 990” manufactured by Mitsubishi Chemical Corporation, average primary particle size 16 nm, DBP oil absorption 101 ml / 100 g
Carbon black-3; “VULCAN9A32” manufactured by Cabot Japan, average primary particle size 19 nm, DBP oil absorption 114 ml / 100 g
Carbon black-4; “# 900” manufactured by Mitsubishi Chemical Corporation, average primary particle diameter 16 nm, DBP oil absorption 46 ml / 100 g
Carbon black-5; “# 960” manufactured by Mitsubishi Chemical Corporation, average primary particle size 16 mg, DBP oil absorption 64 ml / 100 g
Carbon black-6; “# 30” manufactured by Mitsubishi Chemical Corporation, average primary particle size 30 nm, DBP oil absorption 104 ml / 100 g
Carbon black-7; “Raven 5000 ULTRA II” manufactured by Columbia, average primary particle size 8 nm, DBP oil absorption 95 ml / 100 g

Master Badge:
Masterbatch-1; a composition masterbatch-2 obtained by melt-kneading polyamide MXD6 and carbon black-1 at a ratio of polyamide MXD6 / carbon black-1 = 70/30 (weight ratio); polyamide MXD6 and carbon Composition masterbatch-3 obtained by melt-kneading black-2 at a ratio of polyamide MXD6 / carbon black-2 = 70/30 (weight ratio); polyamide MXD6 and carbon black-3 were converted to polyamide MXD6 / carbon Composition master batch -4 obtained by melt-kneading at a ratio of black-3 = 70/30 (weight ratio); polyamide MXD6 and carbon black-4 were mixed with polyamide MXD6 / carbon black-4 = 70/30 (weight) Composition) masterbatch-5 obtained by melt-kneading at a ratio of Composition MXD6 and carbon black-5 were melt-kneaded at a ratio of polyamide MXD6 / carbon black-5 = 70/30 (weight ratio); Composition masterbatch-7 obtained by melt-kneading at a ratio of polyamide MXD6 / carbon black-6 = 70/30 (weight ratio); polyamide MXD6 and carbon black-7 were mixed with polyamide MXD6 / carbon black-7 = 70 Composition obtained by melt kneading at a ratio of / 30 (weight ratio)

(C) Inorganic filler:
Glass fiber: “CS03T-296GH” manufactured by Nippon Electric Glass Co., Ltd., average fiber diameter 9.5 μm, fiber length 3 mm, surface treatment available

Other additives:
Release agent; Ketone wax, “Roxyol EP2036-18” manufactured by Cognis Japan
Nucleating agent: Talc, Hayashi Kasei "micelleton", number average particle size 1.4μm

[Masterbatch-1 to Masterbatch-7]
Polyamide MXD6 and various carbon blacks were weighed so that polyamide MXD / carbon black = 70/30 by weight ratio, and mixed well with a tumbler mixer. ) From the main hopper, and melt kneaded at a cylinder set temperature of 275 ° C. and a screw rotation speed of 300 rpm. The melt-kneaded product was extruded into a strand shape, cooled, and cut to produce pellets.

[Examples 1-3 and Comparative Examples 1-4]
Each material was weighed so that polyamide MXD6 30% by weight, polyamide 66 5% by weight, masterbatch 17% by weight, glass fiber 47% by weight, release agent 0.2% by weight, and nucleating agent 0.8% by weight, Materials other than glass fibers were mixed with a mixing device. The mixture is supplied from the main hopper of a twin screw extruder (“TEM35B” manufactured by Toshiba Machine Co., Ltd.), and the glass fiber is supplied from a side feeder in the middle of the extruder, melted and kneaded at 280 ° C., extruded into a strand, and cooled. And cut to produce pellets. The carbon black content in the pellet is 10.9 parts by weight with respect to 100 parts by weight of the polyamide resin, the inorganic filler content is 100 parts by weight with respect to 100 parts by weight of the polyamide resin, and the release agent content is polyamide. 0.4 parts by weight with respect to 100 parts by weight of the resin, and the content of the nucleating agent is 1.7 parts by weight with respect to 100 parts by weight of the polyamide resin.

After drying the pellets obtained by the above method at 80 ° C. for 12 hours, using an injection molding machine (“ROBOSHOT α-100iA” manufactured by FANUC) using a mirror-finished # 3000 finished mold, the following A 70 mm × 70 mm × 2 mm mirror-finished flat plate for weather resistance evaluation was molded at a cylinder temperature of 280 ° C. and a mold temperature of 130 ° C. The test piece was subjected to the following xenon weathering test. The L value, the color difference ΔE, and the surface appearance of the specular flat plate when the total irradiation amount was 500 kJ / m ² and 2000 kJ / m ² were evaluated by the methods described below. The results are shown in Table 1.

<Evaluation method>
[Xenon Weather Test]
Equipment used: Atlas Ci4000
Filter / inner; Quartz filter / outer; Type S borosilicate black panel temperature; 63 ° C
Irradiance: 0.55 W / m ² (at 340 nm)
Total irradiation amount: 500 kJ / m ² , 2000 kJ / m ² (at 340 nm)
Water spray time; 18 minutes Water spray stop time; 120 minutes Humidity; 50% (95% during rain)
[L value]
The specular flat plate after the xenon weather test was measured using a multi-light source spectrocolorimeter (MSC-5N-GV5) manufactured by Suga Test Instruments Co., Ltd. The light source system was d / 8 condition, and the light flux was Φ15 mm. The smaller the L value, the higher the blackness and the better.
[Color difference ΔE]
About the mirror surface flat plate before and after the xenon weathering test, the hue difference (ΔE) before and after the xenon weathering test was measured by a reflection method according to the method of JIS Z8722 standard. A multi-light source spectrocolorimeter (MSC-5N-GV5) manufactured by Suga Test Instruments Co., Ltd. was used for the measurement. The light source system was d / 8 condition, and the light flux was Φ15 mm. The smaller the value of ΔE, the better the weather resistance.
[Surface appearance]
The surface appearance of the mirror-finished flat plate after the xenon weathering test was observed with an optical microscope (magnification 100 times) and evaluated in the following three stages.
○: almost no exposure of glass fiber can be confirmed Δ; exposure of glass fiber can be confirmed ×: exposure of glass fiber can be confirmed intensely

Claims (9)

(A) A resin composition comprising (B) 0.1 to 30 parts by weight of carbon black and (C) 0 to 200 parts by weight of an inorganic filler with respect to 100 parts by weight of a polyamide resin, An average primary particle diameter of 10 to 25 nm and a DBP oil absorption of 70 ml / 100 g or more is a polyamide resin composition. The polyamide resin composition according to claim 1, wherein the (A) polyamide resin contains 1 to 40% by weight of an aliphatic polyamide resin and 99 to 60% by weight of a semi-aromatic polyamide resin. The polyamide resin composition according to claim 2, wherein the semi-aromatic polyamide resin is a polycondensate of xylylenediamine and an α, ω-linear aliphatic dibasic acid. The polyamide resin composition according to claim 2 or 3, wherein the aliphatic polyamide resin is polyamide 6 or polyamide 66. The polyamide resin composition according to any one of claims 1 to 4, wherein (B) carbon black has an average primary particle diameter of 14 to 20 nm and a DBP oil absorption of 70 to 150 ml / 100 g. object. The polyamide resin composition according to any one of claims 1 to 5, wherein the content of (B) carbon black is 1 to 20 parts by weight. (C) Content of an inorganic filler is 50-150 weight part, The polyamide resin composition of any one of Claims 1-6 characterized by the above-mentioned. A master batch of carbon black in which (B) carbon black is melt kneaded in part of (A) polyamide resin in advance, and the remaining (A) polyamide resin and (C) inorganic filler are melt kneaded. The polyamide resin composition according to any one of claims 1 to 7. A master batch of carbon black in which (B) carbon black is melt kneaded in part of (A) polyamide resin in advance, and the remaining (A) polyamide resin and (C) inorganic filler are melt kneaded. The manufacturing method of the polyamide resin composition of any one of Claims 1-7.