JP6690230B2 - Polyamide resin composition and molded article made of the same - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a polyamide resin composition containing a polyamide resin, a fibrous reinforcing material, a white pigment having a Mohs hardness of less than 5, a phosphorus-based heat-resistant agent and a hindered phenol-based antioxidant, and a molded article formed thereof.

  Polyamide resin has excellent mechanical properties, flame retardancy, electrical properties, heat resistance, molding processability, etc., so it can be used as industrial parts such as automobile parts and electric / electronic parts, and daily necessities such as daily furniture. Widely used. When used for parts such as daily necessities, various colors are required. Particularly in recent years, a material having high brightness has been demanded, and for example, a polyamide resin composition containing a polyamide, a fibrous reinforcing material, and a white pigment such as titanium oxide has been proposed (for example, Patent Document 1). reference). However, the resin composition containing titanium oxide has a problem that impact strength is lowered.

  On the other hand, by using zinc sulfide as a white pigment, it is possible to suppress the reduction in impact strength, but when used for a long period of time in an environment exposed to sunlight, the impact strength and color tone are reduced, and However, there was a problem that mechanical properties were deteriorated by the heat history of, that is, retention stability was insufficient. On the other hand, a resin composition in which a synthetic resin is mixed with zinc sulfide, a hindered amine compound, and a benzoate compound (see, for example, Patent Document 2), and a resin composition in which a resin is mixed with zinc sulfide and a hindered amine compound ( For example, refer to Patent Document 3). Although these techniques suppress the deterioration of color tone due to light irradiation, there is a problem that the impact strength decreases when used for a long time in an environment exposed to sunlight.

JP, 2013-67786, A JP, 2005-48077, A JP, 2009-120723, A

  The present invention provides a polyamide resin composition which is a molded article having high brightness and excellent in designability, which has a high impact strength and in which a color tone change and a decrease in impact strength due to light irradiation are suppressed. The task is to do.

As a result of intensive studies to solve the above problems, the present inventors have found that a polyamide containing a polyamide resin, a fibrous reinforcing material, a white pigment having a Mohs hardness of less than 5, a phosphorus-based heat-resistant agent, and a hindered phenol-based antioxidant. It was found that the above objects can be achieved by the resin composition, and the present invention has been completed. That is, the present invention is as follows.
(A) 5 to 100 parts by weight of the fibrous reinforcing material, (C) 0.1 to 9 parts by weight of a white pigment having a Mohs hardness of less than 5, and (D) a phosphorus-based heat-resistant material, relative to 100 parts by weight of the polyamide resin. A polyamide resin composition comprising 0.2 to 2 parts by weight of an agent and 0.2 to 2 parts by weight of (E) a hindered phenolic antioxidant,
The (A) polyamide resin contains a polyamide resin having a melting point of 190 ° C. or higher and 240 ° C. or lower measured by (A1) differential scanning calorimetry (DSC), and (A) the total amount of polyamide resin is 100% by weight, (A1) differential scanning Including 60% by weight or more of a polyamide resin having a melting point of 190 ° C. or higher and 240 ° C. or lower measured by calorimetry (DSC),
(B) the fibrous reinforcement is (B1) a glass fiber containing polyurethane on the surface,
(D) the phosphorus-based heat-resistant agent is tris (2,4-di-t-butylphenyl) phosphite,
(E) The hindered phenolic antioxidant is N, N ′-(hexane-1,6-diyl) bis [4-hydroxy-3,5-bis (t-butyl) benzenepropanamide],
A polyamide resin composition having a lightness L * in the CIELAB space of 60 or more when a Type-IA multipurpose test piece of ISO3167 standard is molded and measured using a D65 light source.
(2) The polyamide resin composition according to (1), wherein the white pigment (C) contains zinc sulfide.
(3) Xenon arc lamp with irradiance of 150 ± 10 W / m 2 and quartz for an ISO strip test piece obtained by molding a Type-IA multi-purpose test piece of ISO3167 standard and cutting it from the parallel part of the multi-purpose test piece. / # 295 filter (inside / outside), after a weathering treatment for 480 hours under the condition of black panel temperature 63 ± 3 ° C and no rain, the Charpy impact strength (without notch) measured according to ISO179 is 65 kJ / m2 or more, and the Charpy impact strength retention rate before and after weathering treatment ((Charpy impact strength after weathering treatment / Charpy impact strength before weathering treatment) × 100) is 95% or more (1) or (2 ) Polyamide resin composition described.
(4) A molded product comprising the polyamide resin composition according to any one of claims 1 to 5 .
(5) The molded article according to (4), which is an automobile exterior part, a home appliance exterior part, or a daily necessities part.

  According to the polyamide resin composition of the present invention, it is possible to obtain a molded article having high brightness and excellent in designability, which has high impact strength and whose color tone change and impact strength reduction due to light irradiation are suppressed. it can.

  Embodiments of the present invention will be described below. In the present invention, “weight” means “mass”.

  The polyamide resin composition of the present invention comprises (A) a polyamide resin, (B) a fibrous reinforcement, (C) a white pigment having a Mohs hardness of less than 5, (D) a phosphorus-based heat-resistant agent, and (E) a hindered phenol-based composition. Contains antioxidants. By including a white pigment having a Mohs hardness of less than 5 together with the (A) polyamide resin and the (B) fiber reinforcement, the brightness while maintaining the impact strength of the (A) polyamide resin and the (B) fiber reinforcement. And the change in color tone due to light irradiation can be suppressed, but the impact strength is reduced by light irradiation. On the other hand, by including (D) the phosphorus-based heat-resistant agent and (E) the hindered phenol-based antioxidant, it is possible to extremely effectively suppress the decrease in impact strength due to light irradiation.

  The (A) polyamide resin used in the present invention contains amino acids, lactams or diamines and dicarboxylic acids as main raw materials. Examples of these raw materials include amino acids such as 6-aminocaproic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid and paraaminomethylbenzoic acid, lactams such as ε-caprolactam and ω-laurolactam, tetramethylenediamine and hexamethylene. Diamine, 1,5-pentanediamine, 2-methylpentamethylenediamine, nonamethylenediamine, undecamethylenediamine, dodecamethylenediamine, 2,2,4- / 2,4,4-trimethylhexamethylenediamine, 5-methyl Aliphatic diamines such as nonamethylenediamine, aromatic diamines such as metaxylenediamine, paraxylenediamine, 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 Alicyclic diamines such as aminoethylpiperazine, adipic acid, suberic acid, azelaic acid, sebacic acid, aliphatic dicarboxylic acids such as dodecanedioic acid, terephthalic acid, isophthalic acid, 2-chloroterephthalic acid, 2-methylterephthalic acid Aromatic dicarboxylic acids such as 5-methylisophthalic acid, 5-sodiumsulfoisophthalic acid, 2,6-naphthalenedicarboxylic acid, hexahydroterephthalic acid, hexahydroisophthalic acid, 1,2-cyclohexanedicarboxylic acid, 1,3- Fats such as cyclopentanedicarboxylic acid Such as family dicarboxylic acid, and the like. In the present invention, two or more kinds of homopolymers or copolymers derived from these raw materials may be contained.

  Among the polyamide resins obtained from these raw materials, in the present invention, the polyamide resin having a melting point of 190 ° C. or higher and 240 ° C. or lower measured by (A1) differential scanning calorimetry (DSC) is preferable. By using a polyamide resin having a melting point of 190 ° C. or higher, it is possible to further improve the lightness of the molded product, further suppress the color tone change and impact strength reduction due to light irradiation, and further improve the retention stability. On the other hand, by using a polyamide resin having a melting point of 240 ° C. or less, it is possible to further improve the brightness of the molded product, further suppress the color tone change and impact strength reduction due to light irradiation, and further improve the retention stability. A polyamide resin having a melting point of 190 ° C. or higher and 220 ° C. or lower measured by differential scanning calorimetry (DSC) is more preferable.

  Here, regarding the melting point of the polyamide resin (A), about 5 mg of the polyamide resin was sampled, and the polyamide resin was heated from 40 ° C. to 300 ° C. at a heating rate of 20 ° C./min in a nitrogen atmosphere using a differential scanning calorimeter. After raising the temperature and holding at 300 ° C. for 1 minute, the temperature is lowered from 300 ° C. to 40 ° C. at a temperature lowering rate of 20 ° C./minute, held at 40 ° C. for 1 minute, and again from 40 ° C. to 300 ° C. at 20 ° C./minute. It can be determined from the temperature of the endothermic peak observed when the temperature is raised at the temperature raising rate.

  (A1) Examples of the polyamide resin having a melting point of 190 ° C. or higher and 240 ° C. or lower measured by differential scanning calorimetry (DSC) include, for example, polycaproamide (nylon 6), polyhexamethylene sebacamide (nylon 610), and polyhexa. Methylenedodecamide (nylon 612), polycaproamide / polyhexamethyleneadipamide copolymer (nylon 6/66), polyhexamethyleneadipamide / polyhexamethyleneisophthalamide copolymer (nylon 66 / 6I), polyhexamethyleneazide Pamide / polyhexamethylene terephthalamide / polyhexamethylene isophthalamide copolymer (nylon 66 / 6T / 6I), polyhexamethylene adipamide / polyhexamethylene isophthalamide / polycaproamide copolymer (nylon 66 / I / 6), poly-xylylene adipamide (nylon XD6), and the like.

  The polyamide resin composition of the present invention may contain two or more kinds of (A) polyamide resin. In this case, it is preferable to include 60% by weight or more of the above-mentioned (A1) polyamide resin having a melting point of 190 ° C. or higher and 240 ° C. or lower in 100% by weight of the total amount of the (A) polyamide resin, thereby further improving the brightness of the molded product, It is possible to further suppress changes in color tone and reduction in impact strength due to irradiation, and further improve retention stability. It is more preferable to include 70% by weight or more, and more preferably 80% by weight or more of (A1) polyamide resin having a melting point of 190 ° C. or higher and 240 ° C. or lower in 100% by weight of the total amount of (A) polyamide resin.

  The molecular weight of the (A) polyamide resin used in the present invention is not particularly limited, but the relative viscosity measured at 25 ° C. in a 98% concentrated sulfuric acid solution having a resin concentration of 0.01 g / ml is 1.8 to 5. It is preferably in the range of 0. When the relative viscosity is 1.8 or more, the retention stability of the polyamide resin composition can be further improved, and the change in color tone due to light irradiation can be further suppressed. On the other hand, when the relative viscosity is 5.0 or less, the moldability can be improved.

  Examples of the (B) fibrous reinforcing material used in the present invention include glass fibers, PAN (polyacrylonitrile) -based or pitch-based carbon fibers, stainless fibers, metal fibers such as aluminum fibers and brass fibers, and aromatic polyamide fibers. Fiber such as organic fiber, gypsum fiber, ceramic fiber, asbestos fiber, zirconia fiber, alumina fiber, silica fiber, titanium oxide fiber, silicon carbide fiber, rock wool, potassium titanate whiskers, silicon nitride whiskers, whisker reinforcement There are materials. You may include 2 or more types of these. Among these, glass fiber is preferable, and impact strength can be improved. The length of the (B) fibrous reinforcing material is not particularly limited as long as it is generally used for reinforcing a resin, and for example, long fiber type or short fiber type chopped strands, milled fibers and the like can be used.

  (B) The fibrous reinforcing material may have its surface treated with a coupling agent or the like, or may be coated or bundled with a thermoplastic resin such as an ethylene / vinyl acetate copolymer or a thermosetting resin such as an epoxy resin. It may have been done. In the present invention, from the viewpoint of improving the affinity with the polyamide resin (A), it is preferable that the surface of the reinforcing material (B2) contains glass fibers containing polyurethane, and the lightness of the molded product is further improved by light irradiation. It is possible to further suppress color tone change and impact strength reduction, and further improve retention stability.

  The polyamide resin composition of the present invention contains 5 to 100 parts by weight of the (B) fibrous reinforcing material with respect to 100 parts by weight of the (A) polyamide resin. If the content of the (B) fibrous reinforcing material is less than 5 parts by weight, the impact strength decreases. The content of the (B) fibrous reinforcing material is preferably 10 parts by weight or more, and more preferably 40 parts by weight or more. On the other hand, when the content of the (B) fibrous reinforcing material exceeds 100 parts by weight, the lightness decreases and the change in color tone due to light irradiation increases. The content of the (B) fibrous reinforcing material is preferably 90 parts by weight or less, more preferably 85 parts by weight or less.

  The polyamide resin composition of the present invention contains (C) a white pigment having a Mohs hardness of less than 5. The white pigment in the present invention refers to a mineral having the effect of increasing the brightness of a molded article by including it. When the Mohs hardness of the white pigment exceeds 5, the impact strength decreases due to the breakage of the (B) fibrous reinforcing material, but in the present invention, by using the (C) white pigment having a Mohs hardness of less than 5, It is possible to suppress the breakage of the (B) fibrous reinforcing material in the molded product and improve the impact strength.

  Here, the Mohs hardness represents the hardness for minerals and can be measured using a commercially available 10-step Mohs hardness meter. Specifically, after the white pigment and each mineral used as a grade in a 10-step Mohs hardness meter are rubbed together, the presence or absence of scratches is visually observed. When both the white pigment and the mineral of a specific grade are damaged or not damaged, the Mohs hardness of the white pigment is the same grade as the mineral of the specific grade used. In addition, in all grades of minerals, if either the white pigment or the mineral of a specific grade is damaged, the white pigment of the minerals used as the grade in the 10-step Mohs hardness tester is damaged. The Mohs hardness of the white pigment is 0.5 higher than the highest grade of minerals that was not present.

  Examples of white pigments having a Mohs hardness of less than 5 include zinc sulfide (Mohs hardness 4), calcium carbonate (Mohs hardness 3), zinc oxide (Mohs hardness 4), calcium sulfate (Mohs hardness 2), and the like. You may include 2 or more types of these. Among these, zinc sulfide and calcium carbonate are preferable, and zinc sulfide is more preferable, from the viewpoints of further improving the lightness of the molded product, further suppressing color tone change and impact strength reduction due to light irradiation, and further improving retention stability. .

  The polyamide resin composition of the present invention contains (C) 0.1 to 9 parts by weight of a white pigment having a Mohs hardness of less than 5 with respect to 100 parts by weight of the polyamide resin. When the content of the white pigment (C) having a Mohs hardness of less than 5 is less than 0.1 part by weight, the lightness of the molded product is lowered and the impact strength is lowered due to light irradiation. On the other hand, when the content of the white pigment (C) having a Mohs hardness of less than 5 exceeds 9, the impact strength is significantly reduced. The content of the (C) white pigment having a Mohs hardness of less than 5 is preferably 3 parts by weight or less.

  Examples of the phosphorus-based heat-resistant agent (D) used in the present invention include organic phosphorus-based heat-resistant agents and inorganic phosphorus-based heat-resistant agents. Examples of the organic phosphorus-based heat-resistant agent include phosphite ester, phosphate ester, and condensates thereof. Specific examples include triphenylphosphite, tris (nonylphenyl) phosphite, and dilauryl hydrogenphosphite. Fight, triethylphosphite, tridecylphosphite, tris (2-ethylhexyl) phosphite, tris (tridecyl) phosphite, tristearylphosphite, diphenylmonodecylphosphite, monophenyldidecylphosphite, diphenylmono (tridecyl) Phosphite, tetraphenyl dipropylene glycol diphosphite, tetraphenyl tetra (tridecyl) pentaerythritol tetraphosphite, hydrogenated bisphenol A phenol phosphite polymer, diphenyl high Rogen phosphite, 4,4′-butylidene-bis (3-methyl-6-t-butylphenyldi (tridecyl) phosphite), tetra (tridecyl) 4,4′-isopropylidenediphenylphosphite, bis (tridecyl) ) Pentaerythritol diphosphite, bis (nonylphenyl) pentaerythritol diphosphite, dilauryl pentaerythritol diphosphite, distearyl pentaerythritol diphosphite, tris (4-t-butylphenyl) phosphite, tris (2,2) 4-di-t-butylphenyl) phosphite, hydrogenated bisphenol A pentaerythritol phosphite polymer, tetrakis (2,4-di-t-butylphenyl) 4,4'-biphenylene phosphonite, bis (2,4) -Di-t-butyl Phenyl) pentaerythritol diphosphite, bis (2,6-di-t-butyl-4-methylphenyl) pentaerythritol diphosphite, 2,2'-methylenebis (4,6-di-t-butylphenyl) octyl Phosphite, ethyl diethyl phosphonoacetate, methyl acid phosphate, ethyl acid phosphate, butyl acid phosphate, butoxyethyl acid phosphate, octyl acid phosphate, decyl acid phosphate, lauryl acid phosphate, stearyl acid phosphate, oleyl acid phosphate, behenyl acid phosphate, Phenyl acid phosphate, nonyl phenyl acid phosphate, cyclohexyl acid phosphate, phenoxyethyl acid Dephosphate, phenoxyethyl acid phosphate, alkoxypolyethylene glycol acid phosphate, bisphenol A acid phosphate, diethyl phosphate, dibutyl phosphate, dioctyl phosphate, dilauryl phosphate, distearyl phosphate, diphenyl phosphate, bisnonylphenyl phosphate, hexamethylphosphoric triamide Etc. Examples of the inorganic phosphorus heat-resistant agent include salts of phosphoric acid or phosphorous acid and metal ions, and specifically, monosodium phosphate, disodium phosphate, trisodium phosphate, sodium phosphite, calcium phosphite. , Magnesium phosphite, manganese phosphite and the like. You may include 2 or more types of these. Among these, organic phosphorus-based heat-resistant agents are preferable from the viewpoint of further improving impact strength and further suppressing color tone change and impact strength reduction due to light irradiation.

  The polyamide resin composition of the present invention contains 0.2 to 2 parts by weight of the phosphorus-based heat-resistant agent (D) with respect to 100 parts by weight of the (A) polyamide resin. When the content of the phosphorus-based heat-resistant agent (D) is less than 0.2 part by weight, the impact strength decreases due to light irradiation. On the other hand, when the content of the phosphorus-based heat-resistant agent (D) exceeds 2 parts by weight, the impact strength is significantly reduced.

  The (E) hindered phenolic antioxidant in the present invention refers to a compound containing a phenol having one or more alkyl groups of any one of primary to tertiary at the ortho position of the hydroxyl group, for example, 2,6- Di-t-butyl-p-cresol, 2,6-diphenyl-4-octadecyloxyphenol, stearyl (3,5-di-t-butyl-4-hydroxyphenyl) propionate, distearyl (3,5-di- t-butyl-4-hydroxybenzyl) phosphonate, tridecyl-3,5-di-t-butyl-4-hydroxybenzylthioacetate, thiodiethylenebis [(3,5-di-t-butyl-4-hydroxyphenyl) Propionate], 4,4'-thiobis (6-t-butyl-m-cresol), 2-octylthio-4,6-di (3,3) -Di-t-butyl-4-hydroxyphenoxy) -s-triazine, 2,2'-methylenebis (4-methyl-6-t-butylphenol), bis [3,3-bis (4-hydroxy-3-t) -Butylphenyl) butyric acid] glycol ester, 4,4'-butylidene bis (2,6-di-t-butylphenol), 4,4'-butylidene bis (6-t-butyl-3-methylphenol), 2, 2'-ethylidene bis (4,6-di-t-butylphenol), 1,1,3-tris (2-methyl-4-hydroxy-5-t-butylphenyl) butane, bis [2-t-butyl- 4-Methyl-6- (2-hydroxy-3-t-butyl-5-methylbenzyl) phenyl] terephthalate, 1,3,5-tris (2,6-dimethyl-3-hydroxy) -4-t-butylbenzyl) isocyanurate, 1,3,5-tris (3,5-di-t-butyl-4-hydroxybenzyl) isocyanurate, 1,3,5-tris (3,5-di) -T-butyl-4-hydroxybenzyl) -2,4,6-trimethylbenzene, 1,3,5-tris [(3,5-di-t-butyl-4-hydroxyphenyl) propionyloxyethyl] isocyanurate , Tetrakis [methylene-3- (3 ', 5'-di-t-butyl-4'-hydroxyphenyl) propionate] methane {alias tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl] ) Propionyloxymethyl] methane}, 2-t-butyl-4-methyl-6- (2-acryloyloxy-3-t-butyl-5-methylbenzyl) phenol, 3 , 9-Bis [2- (3-t-butyl-4-hydroxy-5-methylhydrocinnamoyloxy) -1,1-dimethylethyl] -2,4,8,10-tetraoxaspiro [5.5 ] Undecane, triethylene glycol bis [β- (3-t-butyl-4-hydroxy-5-methylphenyl) propionate], α-tocopherol, β-tocopherol, γ-tocopherol, δ-tocopherol, N, N′- (Hexane-1,6-diyl) bis [4-hydroxy-3,5-bis (t-butyl) benzenepropanamide] and the like can be mentioned. You may include 2 or more types of these. Among these, hindered phenolic antioxidants having a t-butyl group at the ortho position of the hydroxyl group in the molecule are preferable from the viewpoint of improving impact strength and further suppressing color tone change and impact strength reduction due to light irradiation. Further, a hindered phenolic antioxidant containing an amide group, for example, N, N ′-(hexane-1,6-diyl) bis [4-hydroxy-3,5-bis (t-butyl) benzenepropanamide] is More preferable.

  The polyamide resin composition of the present invention contains 0.2 to 2 parts by weight of the (E) hindered phenolic antioxidant with respect to 100 parts by weight of the (A) polyamide resin. When the content of the (E) hindered phenol-based antioxidant is less than 0.2, the impact strength reduction due to light irradiation increases. On the other hand, when the content of the (E) hindered phenolic antioxidant exceeds 2 parts by weight, the impact strength is significantly reduced.

  The polyamide resin composition of the present invention further comprises (A) a polymer other than the polyamide resin, (D) a heat stabilizer other than the phosphorus-based heat-resistant agent, such as a copper-based heat stabilizer, and sulfur within a range that does not impair the object of the present invention. (E) Antioxidants other than (E) hindered phenolic antioxidants, UV absorbers, lubricants, other release agents, antistatic agents, and usual additives such as colorants including dyes and pigments can do.

The polyamide resin composition of the present invention is characterized in that a Type-IA multipurpose test piece of ISO3167 standard is molded and the lightness L ^* in the CIELAB space when measured using a D65 light source is 60 or more. When the lightness L ^* is less than 60, the impact strength decreases due to light irradiation. From the viewpoint of further suppressing the change in color tone due to light irradiation, the lightness L ^* is more preferably 75 or more.

Here, the lightness L ^* represents the brightness of color, and a Type-IA multipurpose test piece of ISO3167 standard is molded from a polyamide resin composition, and a parallel portion of the test piece is measured by using a D65 light source and a Suga testing machine. It can be measured by SM Color Computer SM-5-IS-2B manufactured by Co., Ltd. In addition, the molding of the ISO1367 standard Type-IA multipurpose test piece is performed by: cylinder temperature: (A) melting point of polyamide resin having the highest melting point of polyamide resin + 20 ° C., mold temperature: 80 ° C., screw rotation speed: 150 rpm, Injection molding is performed under the conditions of the parallel part flow rate: 200 mm / sec and injection / cooling: 20 sec / 20 sec.

The polyamide resin composition having L ^* of 60 or more can be obtained, for example, by setting the content of the white pigment (C) Mohs hardness of less than 5 in the above range. Further, the content of the polyamide resin (A1) having a melting point of 190 ° C. or more and 240 ° C. or less as the polyamide resin (A) is set within the above-mentioned preferable range, and (B2) as a fibrous reinforcing material, polyurethane is included on the surface. L ^* can be further improved by using glass fibers, using zinc sulfide as the white pigment (C) having a Mohs hardness of less than 5, and the like.

The polyamide resin composition of the present invention has an irradiance of 150 ± 10 W / m with respect to an ISO strip test piece obtained by molding a Type-IA multipurpose test piece of ISO3167 standard and cutting it from a parallel part of the multipurpose test piece. Charpy when measured in accordance with ISO179 after weathering 480 hours under conditions of black panel temperature 63 ± 3 ° C and no rain using a xenon arc lamp of ² and a filter of quartz / # 295 (inside / outside). The impact strength (without notch) is 65 kJ / m ² or more, and the Charpy impact strength retention rate before and after weathering treatment ((Charpy impact strength after weathering treatment / Charpy impact strength before weathering treatment) × 100) is 95% or more. It is preferable that

Here, the 480-hour weathering treatment using a xenon arc lamp with an irradiance of 150 ± 10 W / m ² is a condition close to the condition where the molded product is exposed outdoors in Japan for one year, and the Charpy impact before and after the weathering treatment under these conditions is performed. The strength retention rate is an index of deterioration characteristics when a molded product is exposed outdoors. From the viewpoint of further improving the impact strength, both the Charpy impact strength before the weathering treatment and the Charpy impact strength after the weathering treatment are preferably as high as possible, and 65 kJ / m ² or more is preferable. Furthermore, when the Charpy impact strength retention rate before and after weathering is 95% or more, deterioration of mechanical properties due to thermal history during molding is suppressed, and retention stability is improved. The Charpy impact strength retention rate before and after weathering treatment is more preferably 96% or more, further preferably 97% or more.

Charpy impact strength before weathering treatment, from the polyamide resin composition, ISO3167 standard Type-IA multipurpose test piece is injection molded, from the parallel portion of the obtained test piece, length 80mm × width 10mm × thickness 4mm A Charpy impact test piece (without notch) was cut out, and using this Charpy impact test piece, the Charpy impact strength (without notch) was measured for seven measurement samples according to ISO179, and the number average value of the measured values was calculated. It can be obtained by doing. For the Charpy impact strength after weathering, the Charpy impact test piece (without a notch) obtained by the above method was set on a Super Xenon Weather Meter SX2D-75 manufactured by Suga Test Instruments Co., Ltd., and the light source was water-cooled xenon. Arc, filter (inside / outside): Quartz # 295, irradiation illuminance: 150 ± 10 W / m ² , black panel temperature: 63 ± 3 ° C., chamber humidity: 50 ± 10% RH, no rain for 480 hours After the weather resistance treatment, the Charpy impact strength (without notch) is measured for seven measurement samples according to ISO179, and the number average value of the measured values can be calculated. The impact strength retention rate before and after weathering can be calculated by the following (Formula 1) from the Charpy impact strength (before weathering) and the Charpy impact strength (after weathering) obtained by the above method.

  As a means for setting the Charpy impact strength (after weathering treatment) and the impact strength retention rate before and after weathering treatment in the above range, for example, (C) the content of a white pigment having a Mohs hardness of less than 5 is set in the above range. To obtain (A) polyamide resin (A1) having a melting point of 190 ° C. or higher and 240 ° C. or lower in the above-described preferable range, (B) as a fibrous reinforcing material (B2) on the surface The use of glass fibers containing polyurethane, the use of zinc sulfide as the white pigment (C) Mohs hardness of less than 5, and the like can be mentioned.

  The method for producing the polyamide resin composition of the present invention is not particularly limited and, for example, using a kneader such as a single-screw or twin-screw extruder or a kneader, melt kneading at a temperature higher than the melting point of the (A) polyamide resin. And the like.

  By molding the polyamide resin composition of the present invention by a method such as injection molding, extrusion molding or blow molding, a molded product having an arbitrary shape can be obtained. Injection molding is preferable from the viewpoints of mass productivity and improved brightness and impact strength of molded products.

  The obtained molded article is excellent in brightness and impact strength, and is suppressed in color tone change and impact strength reduction due to light irradiation, so that a design property is required and a product that may be exposed to sunlight, such as a bumper. It is suitable for automotive exterior parts such as, exterior parts for home appliances such as personal computer housings and breaker covers, and daily necessities such as binding bands, tables, and resin chairs.

  Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto. The measuring methods used in Examples and Comparative Examples are shown below.

(1) Relative Viscosity of Polyamide Resin A solution in which a polyamide resin was dissolved in 98% concentrated sulfuric acid at a concentration of 1 g / dl was prepared, and the relative viscosity (ηr) was measured at 25 ° C. using an Ostwald viscometer.

(2) Melting Point of Polyamide Resin About 5 mg of the polyamide resin was sampled, and the polyamide resin was heated from 40 ° C. to 300 ° C. at a heating rate of 20 ° C./min using a DSC (differential scanning calorimeter) manufactured by Perkin Elmer under a nitrogen atmosphere. After raising the temperature and holding at 300 ° C. for 1 minute, the temperature is lowered from 300 ° C. to 40 ° C. at a temperature lowering rate of 20 ° C./minute, held at 40 ° C. for 1 minute, and again from 40 ° C. to 300 ° C. at 20 ° C./minute. The temperature of the endothermic peak observed when the temperature was raised at the heating rate was taken as the melting point.

(3) Mohs Hardness of White Pigment After rubbing the white pigment and each mineral used as a class in the 10-step Mohs hardness meter MH-10 manufactured by Yagami Co., Ltd., each of the white pigment and the mineral of a specific class is rubbed. The presence or absence of scratches was visually observed. When both the white pigment and the mineral of a specific grade were scratched or not damaged, the same class as the mineral of the specific grade used was defined as the Mohs hardness of the white pigment. In addition, in all grades of minerals, if either the white pigment or the mineral of a specific grade is damaged, the white pigment of the minerals used as the grade in the 10-step Mohs hardness tester is damaged. The Mohs hardness of the white pigment was 0.5 higher than the highest grade of minerals that was not present. As the white pigment used for measuring the Mohs hardness, a raw material having a size that allows the presence or absence of scratches to be visually determined can be used.

(4) Lightness In accordance with ISO1874-2, a Type-IA multipurpose test piece of ISO3167 standard was injection molded from the pellets obtained in Examples and Comparative Examples. The injection molding was performed by using an injection molding machine NEX1000 manufactured by NISSEI PLASTIC INDUSTRIES CO., LTD., Setting the cylinder temperature to a temperature 20 ° C. higher than the melting point of the polyamide resin having the highest melting point among the polyamide resins used, and the mold temperature. : 80 ° C., screw rotation speed: 150 rpm, parallel part flow rate: 200 mm / sec, injection / cooling: 20/20 sec. With respect to the parallel part of the obtained test piece, the brightness L ^* in the CIELAB space was measured by SM color computer SM-5-IS-2B manufactured by Suga Test Instruments Co., Ltd. using a D65 light source.

(5) Charpy impact strength (no notch)
According to ISO1874-2, a Type-IA multipurpose test piece of ISO3167 standard was injection-molded from the pellets obtained in Examples and Comparative Examples. The injection molding was performed under the conditions described in (4) above. From the parallel portion of the obtained multipurpose test piece, a Charpy impact test piece (without a notch) having a length of 80 mm, a width of 10 mm and a thickness of 4 mm was cut out. The obtained Charpy impact test piece was stored in a moisture-proof aluminum bag. Using this Charpy impact test piece, the Charpy impact strength (without notch) was measured according to ISO179. The number of measurement samples was 7, and the number average value was defined as the Charpy impact strength.

(6) Charpy impact strength retention rate A Charpy impact test piece (without a notch) obtained by the method described in (5) above was set on a Super Xenon Weather Meter SX2D-75 manufactured by Suga Test Instruments Co., Ltd., and a light source was water-cooled. Formula Xenon arc, filter (inside / outside): Quartz # 295, irradiance: 150 ± 10 W / m ² , black panel temperature: 63 ± 3 ° C., chamber humidity: 50 ± 10% RH, no rain, It was weather-treated for 480 hours. The test piece after weathering was dried overnight at 80 ° C. under vacuum and then stored in a moisture-proof aluminum bag. Using this Charpy impact test piece, the Charpy impact strength (without notch) was measured according to ISO179. The number of measurement samples was 7, and the number average value was defined as the Charpy impact strength.

  Further, from the obtained Charpy impact strength (after weathering treatment) and the Charpy impact strength (before weathering treatment) obtained by the method described in (5) above, the impact strength retention rate was obtained by the following (Formula 1). .

(7) Change in color tone Regarding the Charpy impact test piece (before weathering treatment) obtained by the method described in (5) and the Charpy impact test piece obtained after the weathering treatment (6). , D65 light source, Suga Test Instruments Co., Ltd. SM color computer SM-5-IS-2B to measure lightness L ^* , red / green value a ^* , yellow / blue value b ^* in CIELAB space. ΔE ^* _ab was obtained from (Equation 2). In the formula (2), ΔL ^* , Δa ^* , and Δb ^* represent the differences in lightness L ^* , red / green value a ^* , and yellow / blue value b ^* before and after weathering treatment, respectively.

(8) Residence Stability According to ISO1874-2, a Type-IA multipurpose test piece (after residence treatment) of ISO3167 standard was injection-molded from the pellets obtained in Examples and Comparative Examples. The injection molding was performed by using an injection molding machine NEX1000 manufactured by NISSEI PLASTIC INDUSTRIAL CO., LTD. For 20 minutes in a cylinder set to a temperature 20 ° C. higher than the melting point of the polyamide resin having the highest melting point among the polyamide resins used. After that, the mold temperature: 80 ° C., screw rotation speed: 150 rpm, parallel part flow rate: 200 mm / sec, injection / cooling: 20/20 sec. From the parallel portion of the obtained multipurpose test piece, a Charpy impact test piece (without a notch) having a length of 80 mm, a width of 10 mm and a thickness of 4 mm was cut out. The obtained Charpy test piece was stored in a moisture-proof aluminum bag. Using this Charpy test piece, the Charpy impact strength (without notch) with a residence time of 20 minutes was measured according to ISO179. From the obtained value and the Charpy Charpy impact strength (without notch) measured by the method described in (5) above (retention time 0 minute), the retention strength at retention was measured by the following (formula 3).

  The production methods of the raw materials used in Examples and Comparative Examples are shown below.

Reference Example 1 (A1-1) Polyamide 6
It was charged ε- caprolactam polymerization vessel, the water content of the distilled water so that 45 wt% was added, the inside of the polymerization vessel was replaced with N _2, and heated to 260 ° C.. Then, polymerization was carried out while controlling the pressure at 1.7 MPa for 1 hour, followed by discharge and cutting to obtain (A1-1) polyamide 6. The relative viscosity measured by the method described in (1) and (2) above was 2.7 and the melting point was 225 ° C.

Reference Example 2 (A1-2) Polyamide 6/66
15% by weight of equimolar salt of hexamethylenediamine and adipic acid and 85% by weight of ε-caprolactam were put into a polymerization vessel, distilled water was added so that the water content was 45% by weight, and the inside of the polymerization vessel was replaced with N ₂ . After that, the temperature was raised to 260 ° C. Then, after pressure suppression and polymerization at 1.7 MPa for 1 hour, discharge and cutting were carried out to obtain (A1-2) polyamide 6/66. The relative viscosity measured by the method described in (1) and (2) above was 2.7 and the melting point was 194 ° C.

Reference Example 3 (A1-3) Polyamide 66 / 6I / 6
75% by weight of equimolar salt of hexamethylenediamine and adipic acid, 15% by weight of equimolar salt of hexamethylenediamine and isophthalic acid, and 10% by weight of ε-caprolactam were added to a polymerization vessel to obtain a water content of 45% by weight. Thus, distilled water was added, the inside of the polymerization vessel was replaced with N ₂ , and the temperature was raised to 260 ° C. Then, after pressure suppression and polymerization at 1.7 MPa for 1 hour, discharge and cutting were carried out to obtain (A1-3) polyamide 66 / 6I / 6. The relative viscosity measured by the method described in (1) and (2) above was 2.7, and the melting point was 227 ° C.

Reference Example 4 (A2) Polyamide 66
An equimolar salt of hexamethylenediamine and adipic acid was placed in a polymerization vessel, distilled water was added so that the water content was 45% by weight, the inside of the polymerization vessel was replaced with N ₂ , and the temperature was raised to 280 ° C. Then, after pressure suppression and polymerization at 1.7 MPa for 1 hour, discharge and cutting (A2) to obtain polyamide 66. The relative viscosity measured by the method described in (1) and (2) above was 2.8 and the melting point was 265 ° C.

Reference Example 5 (A 3) Polyamide 12
12-Aminododecanoic acid was placed in a polymerization vessel, distilled water was added so that the water content was 45% by weight, the inside of the polymerization vessel was replaced with N2, and the temperature was raised to 260 ° C. Then, after pressure suppression and polymerization at 1.7 MPa for 1 hour, discharge and cutting (A3) polyamide 12 was obtained. The relative viscosity measured by the method described in (1) and (2) above was 2.8 and the melting point was 175 ° C.

Reference Example 6 (B1) Glass fiber (urethane surface treatment)
Polyester-based non-yellowing urethane resin emulsion (HUX-290H manufactured by ADEKA Co., Ltd.) 6.3% by weight and γ-aminopropyltriethoxysilane (KBM-903 manufactured by Shin-Etsu Chemical Co., Ltd.) 0.6% by weight in terms of solid content. %, And deionized water was added to make a sizing agent for glass fibers. This glass fiber sizing agent was applied to the surface of an E glass filament having a diameter of 13 μm, and 2000 pieces were bundled to form a glass fiber strand, which was wound on a paper tube to form a cake. A glass chopped strand was obtained by cutting the cake into 3 mm lengths while unwinding the glass fiber strands and drying.

Reference Example 7 (B2) Glass fiber (acid-based surface treatment)
2.3% by weight of an unsaturated copolymer of maleic anhydride and butadiene and 0.5% by weight of γ-aminopropyltriethoxysilane (KBM-903 manufactured by Shin-Etsu Chemical Co., Ltd.) in terms of solid content were blended and removed. Ionized water was added to produce a glass fiber sizing agent. This glass fiber sizing agent was applied to the surface of an E glass filament having a diameter of 13 μm, and 2000 pieces were bundled to form a glass fiber strand, which was wound on a paper tube to form a cake. A glass chopped strand was obtained by cutting the cake into 3 mm lengths while unwinding the glass fiber strands and drying.

The raw materials used in Examples and Comparative Examples are shown below.
(C) White pigment having a Mohs hardness of less than 5 (C1) Zinc sulfide (Mohs hardness 4)
Sachtolith HD-S (average particle size 0.30 to 0.35 μm) manufactured by Sachtleben Chemie was used.
(C2) Calcium carbonate (Mohs hardness 3) manufactured by Dowa Calfine Co., Ltd .: KSS-1000 (average particle size 1.9 to 2.5 μm) was used.
(C ') white pigment having a Mohs hardness of 5 or more (C') titanium oxide (Mohs hardness 7)
Ishihara Sangyo Co., Ltd .: "Taipeque" (registered trademark) CR-61 (average particle size 0.21 [mu] m) was used.
(D) Phosphorus heat-resistant agent manufactured by BASF: (D1) IRGAFOS 168 (organic) was used.
(E) Hindered phenolic antioxidant BASF: (E1) "IRGANOX" (registered trademark) 1098 (N, N '-(hexane-1,6-diyl) bis [4-hydroxy-3,5-bis] (T-butyl) benzenepropanamide]) was used.
(F) Weathering agent (hindered amine type)
Made by BASF: (F1) Chimasorb 2020FDL was used.

Example 1-10, Comparative Example 1-12
The polyamide resin, the white pigment, the phosphorus-based heat-resistant agent, the hindered phenol-based antioxidant, and the weatherproofing agent shown in Tables 1 and 2 were originally fed from the top feeder of the twin-screw extruder (JSW: TEX30α). Here, the cylinder set temperature of the twin-screw extruder was set to the melting point of the polyamide resin having the highest melting point of the polyamide resins used + 20 ° C. A twin screw extruder and a screw arrangement provided with two kneading zones were used, and the screw rotation speed was set to 265 rpm. The fibrous reinforcing materials shown in Tables 1 and 2 are side-fed and melt-kneaded from between the first kneading zone near the original loading side and the second kneading zone on the downstream side to form a strand-like gut, After cooling in a cooling bath, granulation was performed with a cutter to obtain pellets. Tables 1 and 2 show the results of evaluation by the above-described evaluation method using the obtained pellets.

Claims (5)

(A) 5 to 100 parts by weight of the fibrous reinforcing material, (C) 0.1 to 9 parts by weight of a white pigment having a Mohs hardness of less than 5, and (D) a phosphorus-based heat-resistant material, relative to 100 parts by weight of the polyamide resin. A polyamide resin composition comprising 0.2 to 2 parts by weight of an agent and 0.2 to 2 parts by weight of (E) a hindered phenolic antioxidant,
The (A) polyamide resin contains a polyamide resin having a melting point of 190 ° C. or higher and 240 ° C. or lower measured by (A1) differential scanning calorimetry (DSC), and (A) the total amount of polyamide resin is 100% by weight, (A1) differential scanning Including 60% by weight or more of a polyamide resin having a melting point of 190 ° C. or higher and 240 ° C. or lower measured by calorimetry (DSC),
(B) the fibrous reinforcement is (B1) a glass fiber containing polyurethane on the surface,
(D) the phosphorus-based heat-resistant agent is tris (2,4-di-t-butylphenyl) phosphite,
(E) The hindered phenolic antioxidant is N, N ′-(hexane-1,6-diyl) bis [4-hydroxy-3,5-bis (t-butyl) benzenepropanamide],
A polyamide resin composition having a lightness L * in the CIELAB space of 60 or more when a Type-IA multipurpose test piece of ISO3167 standard is molded and measured using a D65 light source. (C) white pigment is a polyamide resin composition according to claim 1, wherein the zinc sulfide. ISO-3167 standard Type-IA multi-purpose test piece was molded, and the ISO strip test piece obtained by cutting from the parallel part of the multi-purpose test piece was subjected to xenon arc lamp with irradiance 150 ± 10 W / m 2 and quartz / # 295. Charpy impact strength (without notch) of 65 kJ / m2 when measured in accordance with ISO179 after weathering for 480 hours under conditions of no rain and a black panel temperature of 63 ± 3 ° C. The polyamide resin according to claim 1 or 2, wherein the Charpy impact strength retention rate before and after weathering treatment ((Charpy impact strength after weathering treatment / Charpy impact strength before weathering treatment) x 100) is 95% or more. Composition. Claim 1 molded article comprising the polyamide resin composition according to any one of the three. The molded article according to claim 4, which is a vehicle exterior component, a home appliance exterior component, or a daily necessities component.