JP2017115066A - Polyamide resin composition and molded article consisting of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyamide resin composition capable of providing a molded article having high brightness and excellent in designability, high in impact strength and having suppressed color tone change or impact strength reduction by light irradiation.SOLUTION: There is provided a polyamide resin composition containing 100 pts.wt. of (A) a polyamide resin, 5 to 100 pts.wt. of (B) a fibrous strengthening material, (C) 0.1 to 9 pts.wt. of a white pigment having Mohs hardness of less than 5, 0.2 to 2 pts.wt. of (D) a phosphorous heat resistant agent and 0.2 to 2 pts.wt. of (E) a hindered phenolic antioxidant and having brightness Lin a CIELAB space measured by molding a Type-IA multipurpose test piece with ISO 3167 specification and measuring by using a D65 light source of 60 or more.SELECTED DRAWING: None

Description

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

  Polyamide resins are excellent in mechanical properties, flame retardancy, electrical properties, heat resistance, molding processability, etc., so they are used as industrial parts such as automobile parts and electrical and electronic parts, as well as daily necessities such as daily furniture. Widely used. When used for parts such as daily necessities, various colors are required. In particular, in recent years, a material having high brightness has been demanded. For example, a polyamide resin composition containing 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, the impact strength can be prevented from lowering, but when used for a long time in an environment exposed to sunlight, the impact strength and color tone may decrease, There is a problem that the mechanical properties are deteriorated due to the heat history, that is, the retention stability is insufficient. In contrast, a resin composition in which zinc sulfide, a hindered amine compound, and a benzoate compound are blended in a synthetic resin (see, for example, Patent Document 2), or a resin composition in which zinc sulfide and a hindered amine compound are blended in a resin ( For example, see Patent Document 3). Although these techniques suppress a decrease in color tone due to light irradiation, there is a problem in 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 capable of obtaining a molded product having high brightness and excellent in design, having a high impact strength, and suppressing a change in color tone and a decrease in impact strength due to light irradiation. The task is to do.

As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that 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 are contained. It has been found that the object can be achieved by the resin composition, and the present invention has been achieved. That is, the present invention is as follows.
(1) (B) 5 to 100 parts by weight of a fibrous reinforcing material, (C) 0.1 to 9 parts by weight of a white pigment having a Mohs hardness of less than 5, A polyamide resin composition containing 0.2 to 2 parts by weight of a phosphorus-based heat-resistant agent and 0.2 to 2 parts by weight of (E) a hindered phenol-based antioxidant, and molding a Type 3-IA multipurpose test piece of ISO 3167 standard A polyamide resin composition having a lightness L ^* in the CIELAB space of 60 or more when measured using a D65 light source.
(2) The polyamide resin (A) includes (A1) a polyamide resin having a melting point of 190 ° C. or higher and 240 ° C. or lower as measured by differential scanning calorimetry (DSC). The polyamide resin composition according to (1), comprising 60% by weight or more of a polyamide resin having a melting point of 190 ° C. or higher and 240 ° C. or lower as measured by differential scanning calorimetry (DSC).
(3) The polyamide resin composition according to (1) or (2), wherein (C) the white pigment contains zinc sulfide.
(4) The polyamide resin composition according to any one of (1) to (3), wherein (B) the fibrous reinforcing material includes (B2) glass fibers containing polyurethane on the surface.
(5) An ISO 3167 standard Type-IA multi-purpose test piece, and an ISO strip test piece obtained by cutting from a parallel part of the multi-purpose test piece, a xenon arc lamp having an irradiance of 150 ± 10 W / m ² Charpy impact strength when measured according to ISO 179 after weathering for 480 hours using quartz / # 295 filter (inside / outside) under conditions of black panel temperature of 63 ± 3 ° C and no rain Is 65 kJ / m ² or more, and the Charpy impact strength retention before and after the weathering treatment ((Charpy impact strength after weathering treatment / Charpy impact strength before weathering treatment) × 100) is 95% or more (1) to The polyamide resin composition according to any one of (4).
(6) A molded article comprising the polyamide resin composition according to any one of (1) to (5).
(7) The molded article according to (6), which is an automotive 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 product having high brightness and excellent design, which has a high impact strength and suppresses a change in color tone and a decrease in impact strength due to light irradiation. 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 reinforcing material, (C) a white pigment having a Mohs hardness of less than 5, (D) a phosphorus heat-resistant agent, and (E) a hindered phenol type. Contains antioxidants. Lightness while maintaining the impact strength of (A) polyamide resin and (B) fiber reinforcement by including (C) a white pigment having a Mohs hardness of less than 5 together with (A) polyamide resin and (B) fiber reinforcement. Although the color tone change due to light irradiation can be suppressed, the impact strength is reduced by light irradiation. In contrast, by including (D) a phosphorus heat-resistant agent and (E) a hindered phenol-based antioxidant, it is possible to extremely effectively suppress a reduction in impact strength due to light irradiation.

  The (A) polyamide resin used in the present invention is mainly composed of amino acid, lactam or diamine and dicarboxylic acid. 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, hexamethylene Diamine, 1,5-pentanediamine, 2-methylpentamethylenediamine, nonamethylenediamine, undecamethylenediamine, dodecamethylenediamine, 2,2,4- / 2,4,4-trimethylhexamethylenediamine, 5-methyl Aliphatic diamines such as nonamethylene diamine, aromatic diamines such as meta-xylene diamine and para-xylene diamine, 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 Aliphatic diamines such as aminoethylpiperazine, aliphatic dicarboxylic acids such as adipic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, terephthalic acid, isophthalic acid, 2-chloroterephthalic acid, 2-methylterephthalic acid , 5-methylisophthalic acid, 5-sodium sulfoisophthalic acid, 2,6-naphthalenedicarboxylic acid, hexahydroterephthalic acid, hexahydroisophthalic acid and other aromatic dicarboxylic acids, 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 homopolymers or copolymers derived from these raw materials may be contained.

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

  Here, the melting point of the polyamide resin (A) was obtained by collecting about 5 mg of the polyamide resin and using a differential scanning calorimeter in a nitrogen atmosphere at a heating rate of 20 ° C./min from 40 ° C. to 300 ° C. The temperature was raised and held at 300 ° C. for 1 minute, then the temperature was lowered from 300 ° C. to 40 ° C. at a rate of temperature drop 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 increased at the rate of temperature increase.

  (A1) Polyamide resins 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), polyhexa Methylene dodecamide (nylon 612), polycaproamide / polyhexamethylene adipamide copolymer (nylon 6/66), polyhexamethylene adipamide / polyhexamethylene isophthalamide copolymer (nylon 66 / 6I), polyhexamethylene azide 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 (A) polyamide resins. In this case, it is preferable that 60% by weight or more of the above-mentioned polyamide resin (A1) having a melting point of 190 ° C. or higher and 240 ° C. or lower is contained in 100% by weight of the total amount of (A) polyamide resin. It is possible to further suppress a change in color tone and a decrease in impact strength due to irradiation and further improve the retention stability. (A) In a total amount of polyamide resin of 100% by weight, it is more preferable that (A1) a polyamide resin having a melting point of 190 ° C. or higher and 240 ° C. or lower is contained by 70% by weight or more, and more preferably 80% by weight or more.

  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. A range of 0 is preferred. When the relative viscosity is 1.8 or more, the residence stability of the polyamide resin composition can be further improved, and the color tone change due to light irradiation can be further suppressed. On the other hand, if 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 and pitch-based carbon fibers, stainless steel fibers, metal fibers such as aluminum fibers and brass fibers, and aromatic polyamide fibers. Organic fiber such as gypsum fiber, ceramic fiber, asbestos fiber, zirconia fiber, alumina fiber, silica fiber, titanium oxide fiber, silicon carbide fiber, rock wool, potassium titanate whisker, silicon nitride whisker, etc. Materials. Two or more of these may be included. Among these, glass fiber is preferable, and impact strength can be improved. Further, the length of the (B) fibrous reinforcing material is not particularly limited as long as it is generally used for resin reinforcement, and for example, a long fiber type or a short fiber type chopped strand, a milled fiber, or the like can be used.

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

  The polyamide resin composition of the present invention contains 5 to 100 parts by weight of (B) fibrous reinforcing material with respect to 100 parts by weight of (A) polyamide resin. (B) When content of a fibrous reinforcement is less than 5 weight part, impact strength falls. (B) The content of the 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 color tone change due to light irradiation increases. (B) The content of the fibrous reinforcing material is preferably 90 parts by weight or less, and more preferably 85 parts by weight or less.

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

  Here, the Mohs hardness represents the hardness against minerals and can be measured using a commercially available 10-stage Mohs hardness meter. Specifically, after the white pigment and each mineral used as a class in the 10-stage 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 class are damaged or not damaged, the same class as the mineral of the specific class used is defined as the Mohs hardness of the white pigment. In addition, in all classes of minerals, if only one of the white pigment or a specific class of minerals is damaged, the white pigment of the minerals used in the 10-stage Mohs hardness scale is damaged. The value 0.5 higher than the highest mineral class that was not present is the Mohs hardness of the white pigment.

  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. Two or more of these may be included. Among these, zinc sulfide and calcium carbonate are preferable, and zinc sulfide is more preferable from the viewpoint of further improving the brightness of the molded product, further suppressing color change and impact strength reduction due to light irradiation, and further improving retention stability. .

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

  Examples of the phosphorus heat-resistant agent (D) used in the present invention include organic phosphorus heat-resistant agents and inorganic phosphorus heat-resistant agents. Examples of the organic phosphorus heat-resistant agents include phosphites, phosphates, and condensates thereof, and specifically include triphenyl phosphite, tris (nonylphenyl) phosphite, dilauryl hydrogen phosphide. Phyto, triethyl phosphite, tridecyl phosphite, tris (2-ethylhexyl) phosphite, tris (tridecyl) phosphite, tristearyl phosphite, diphenyl monodecyl phosphite, monophenyl didecyl phosphite, diphenyl mono (tridecyl) Phosphite, tetraphenyldipropylene glycol diphosphite, tetraphenyltetra (tridecyl) pentaerythritol tetraphosphite, hydrogenated bisphenol A phenol phosphite polymer, diphenyl high Rogen phosphite, 4,4′-butylidene-bis (3-methyl-6-tert-butylphenyldi (tridecyl) phosphite), tetra (tridecyl) 4,4′-isopropylidene diphenylphosphite, bis (tridecyl) ) Pentaerythritol diphosphite, bis (nonylphenyl) pentaerythritol diphosphite, dilauryl pentaerythritol diphosphite, distearyl pentaerythritol diphosphite, tris (4-t-butylphenyl) phosphite, tris (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 Phenyl acid phosphate, nonyl phenyl acid phosphate, cyclohexyl acid phosphate, phenoxyethyl acid Dophosphate, phenoxyethyl acid phosphate, alkoxy polyethylene 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 inorganic phosphorus heat-resistant agents include salts of phosphoric acid or phosphorous acid and metal ions. Specifically, monosodium phosphate, disodium phosphate, trisodium phosphate, sodium phosphite, calcium phosphite , Magnesium phosphite, manganese phosphite and the like. Two or more of these may be included. Among these, an organic phosphorus heat-resistant agent is preferable from the viewpoint of further improving impact strength and further suppressing color 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 (D) a phosphorus-based heat-resistant agent with respect to 100 parts by weight of (A) the polyamide resin. (D) When content of phosphorus heat-resistant agent is less than 0.2 weight part, the impact strength fall by light irradiation increases. On the other hand, when the content of the (D) phosphorus heat-resistant agent exceeds 2 parts by weight, the impact strength is remarkably lowered.

  The (E) hindered phenol 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 a hydroxyl group. 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-tert-butyl-m-cresol), 2-octylthio-4,6-di (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'-butylidenebis (2,6-di-t-butylphenol), 4,4'-butylidenebis (6-t-butyl-3-methylphenol), 2, 2′-ethylidenebis (4,6-di-tert-butylphenol), 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, bis [2-tert-butyl- 4-methyl-6- (2-hydroxy-3-tert-butyl-5-methylbenzyl) phenyl] terephthalate, 1,3,5-tris (2,6-dimethyl-3-hydroxy) -4-tert-butylbenzyl) isocyanurate, 1,3,5-tris (3,5-di-tert-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 {also known as 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-tert-butyl-4-hydroxy-5-methylhydrocinnamoyloxy) -1,1-dimethylethyl] -2,4,8,10-tetraoxaspiro [5.5 ] Undecane, triethylene glycol bis [[beta]-(3-tert-butyl-4-hydroxy-5-methylphenyl) propionate], [alpha] -tocopherol, [beta] -tocopherol, [gamma] -tocopherol, [delta] -tocopherol, N, N'- (Hexane-1,6-diyl) bis [4-hydroxy-3,5-bis (t-butyl) benzenepropanamide] and the like. Two or more of these may be included. Among these, a hindered phenol-based antioxidant having a t-butyl group at the ortho position of the hydroxyl group in the molecule is preferable from the viewpoint of improving impact strength and further suppressing color change and impact strength reduction due to light irradiation. Furthermore, hindered phenol-based antioxidants containing an amide group, such as N, N ′-(hexane-1,6-diyl) bis [4-hydroxy-3,5-bis (t-butyl) benzenepropanamide], More preferred.

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

  The polyamide resin composition of the present invention further includes (A) a polymer other than the polyamide resin, (D) a heat stabilizer other than the phosphorus heat-resistant agent, such as a copper heat stabilizer, and sulfur, within a range not impairing the object of the present invention. Contains ordinary additives such as antioxidants other than (E) hindered phenolic antioxidants such as UV-based, UV absorbers, lubricants, other mold release agents, antistatic agents, and coloring agents including dyes and pigments can do.

The polyamide resin composition of the present invention is characterized in that the lightness L ^* in the CIELAB space when a Type-IA multipurpose test piece conforming to ISO 3167 standard is measured using a D65 light source is 60 or more. When the lightness L ^* is less than 60, the impact strength reduction due to light irradiation increases. From the viewpoint of further suppressing color tone change due to light irradiation, the lightness L ^* is more preferably 75 or more.

Here, the lightness L ^* represents the brightness of the color. A Type 3-IA multi-purpose test piece of ISO 3167 standard is molded from a polyamide resin composition, and a parallel part of the test piece is subjected to a suga test machine using a D65 light source. It can be measured by SM color computer SM-5-IS-2B manufactured by Co., Ltd. The ISO 1367 standard Type-IA multi-purpose test piece was molded by cylinder temperature: (A) melting point of polyamide resin having the highest melting point among polyamide resins + 20 ° C., mold temperature: 80 ° C., screw rotation speed: 150 rpm, It is performed by injection molding under the conditions of parallel part flow velocity: 200 mm / second, injection / cooling: 20 seconds / 20 seconds.

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

The polyamide resin composition of the present invention is an ISO 3167 standard Type-IA multipurpose test piece, and the ISO strip test piece obtained by cutting from the parallel part of the multipurpose test piece has an irradiance of 150 ± 10 W / m. Charpy when measured according to ISO 179 after weathering for 480 hours under conditions of black panel temperature 63 ± 3 ° C, no rain using xenon arc lamp of ² and quartz / # 295 filter (inside / outside) The impact strength (without notch) is 65 kJ / m ² or more, and the Charpy impact strength retention before and after the 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 a state in which a molded product is exposed outdoors in Japan for one year. The strength retention is an indicator of deterioration characteristics when the 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 higher, and more preferably 65 kJ / m ² or more. Furthermore, if the Charpy impact strength retention before and after the weathering treatment is 95% or more, the deterioration of the mechanical properties due to the thermal history during molding is suppressed, and the retention stability is improved. The Charpy impact strength retention before and after the weathering treatment is more preferably 96% or more, and even more preferably 97% or more.

The Charpy impact strength before the weathering treatment was obtained by injection-molding a Type-IA multipurpose test piece of ISO 3167 standard from a polyamide resin composition, and from the parallel part of the obtained test piece, length 80 mm × width 10 mm × thickness 4 mm Cut out Charpy impact test piece (no notch), measure Charpy impact strength (no notch) for 7 measurement samples according to ISO 179 using this Charpy impact test piece, and calculate the number average value of the measured values Can be obtained. The Charpy impact strength after the weathering treatment was set on the Super Xenon Weather Meter SX2D-75 manufactured by Suga Test Instruments Co., Ltd. by using the Charpy impact test piece (without notch) obtained by the above method. Light source: 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, 480 hours After the weathering treatment, the Charpy impact strength (no notch) is measured for seven measurement samples according to ISO 179, and the number average value of the measurement values can be calculated. Moreover, the impact strength retention before and after the weathering treatment can be calculated by the following (Equation 1) from the Charpy impact strength (before weathering treatment) and the Charpy impact strength (after weathering treatment) obtained by the above method.

  Examples of means for bringing the Charpy impact strength (after weathering treatment) and the impact strength retention before and after the weathering treatment into the above range include, for example, (C) the content of the white pigment having a Mohs hardness of less than 5 within the above range. (A) As a polyamide resin, (A1) The content of a polyamide resin having a melting point of 190 ° C. or higher and 240 ° C. or lower is within the above-mentioned preferable range, (B) As a fibrous reinforcing material (B2) on the surface Examples thereof include using glass fibers containing polyurethane, and (C) using zinc sulfide as a white pigment having a Mohs hardness of less than 5.

  The method for producing the polyamide resin composition of the present invention is not particularly limited. For example, using a kneader such as a single or twin screw extruder or a kneader, (A) melt kneading at a temperature higher than the melting point of the 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. From the viewpoint of further improving the mass productivity and the brightness and impact strength of the molded product, injection molding is preferred.

  The obtained molded product is excellent in lightness and impact strength, and since color change and impact strength decrease due to light irradiation are suppressed, a product that is required to have a design property and may be exposed to sunlight, such as a bumper. It is suitable for automobile exterior parts such as personal computer casings and breaker covers, and household goods such as cable ties, tables, and resin chairs.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated further in detail, this invention is not limited by these. Measurement 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 polyamide resin was collected, and the polyamide resin was heated from 40 ° C. to 300 ° C. at a rate of 20 ° C./min using a Perkin Elmer DSC (differential scanning calorimeter) in a nitrogen atmosphere. The temperature was raised and held at 300 ° C. for 1 minute, then the temperature was lowered from 300 ° C. to 40 ° C. at a rate of temperature drop 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 rate of temperature rise 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-stage Mohs hardness tester MH-10 manufactured by Yagami Co., Ltd., each of the white pigment and a specific class of mineral The presence or absence of scratches was visually observed. When both the white pigment and the mineral of a specific class were damaged or not damaged, the same class as the mineral of the specific class used was defined as the Mohs hardness of the white pigment. In addition, in all classes of minerals, if only one of the white pigment or a specific class of minerals is damaged, the white pigment of the minerals used in the 10-stage Mohs hardness scale is damaged. The value 0.5 higher than the highest mineral class that was not present was taken as the Mohs hardness of the white pigment. In addition, as a white pigment used for the measurement of Mohs hardness, the raw material before the grinding | pulverization which has a magnitude | size which can determine the presence or absence of a flaw visually was used.

(4) Lightness According to ISO1874-2, a Type-IA multipurpose test piece of ISO 3167 standard was injection-molded from the pellets obtained in Examples and Comparative Examples. Injection molding is performed by using an injection molding machine NEX1000 manufactured by Nissei Plastic Industry Co., Ltd., and 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 used polyamide resins. : 80 ° C., screw rotation speed: 150 rpm, parallel part flow velocity: 200 mm / sec, injection / cooling: 20/20 sec. About the parallel part of the obtained test piece, the lightness L ^* in CIELAB space was measured by Suga Test Instruments Co., Ltd. SM color computer SM-5-IS-2B using D65 light source.

(5) Charpy impact strength (no notch)
In accordance with ISO1874-2, a Type-IA multipurpose test piece of ISO 3167 standard was injection molded from the pellets obtained in Examples and Comparative Examples. Injection molding was performed under the conditions described in (4) above. A Charpy impact test piece (no notch) having a length of 80 mm, a width of 10 mm and a thickness of 4 mm was cut out from the parallel part of the obtained multipurpose test piece. The obtained Charpy impact test piece was stored in a moisture-proof aluminum bag. Using this Charpy impact test piece, Charpy impact strength (no 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 Charpy impact test piece (without 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. 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, with no rain, Weathered for 480 hours. The test piece after the weathering treatment was dried overnight at 80 ° C. under vacuum, and then stored in a moisture-proof aluminum bag. Using this Charpy impact test piece, Charpy impact strength (no 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.

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

(7) Color tone change About Charpy impact test piece (before weathering treatment) obtained by the method described in (5) above and Charpy impact test piece (after weathering treatment) obtained by the method described in (6) above The lightness L ^* , red / green value a ^* , and yellow / blue value b ^* in CIELAB space were measured with SM color computer SM-5-IS-2B manufactured by Suga Test Instruments Co., Ltd. using a D65 light source. ΔE ^* _ab was determined by (Equation 2). In the formula (2), ΔL ^* , Δa ^* , and Δb ^* represent the difference between the brightness L ^* , the red / green value a ^* , and the yellow / blue value b ^* before and after the weathering treatment, respectively.

(8) Stability of Stabilization According to ISO1874-2, Type 3-IA multi-purpose test piece (after residence treatment) of ISO 3167 standard was injection-molded from the pellets obtained in Examples and Comparative Examples. Injection molding is carried out for 20 minutes in a cylinder set at a temperature 20 ° C. higher than the melting point of the polyamide resin having the highest melting point among the polyamide resins used, using an injection molding machine NEX1000 manufactured by Nissei Plastic Industry Co., Ltd. Thereafter, the mold temperature was 80 ° C., the screw rotation speed was 150 rpm, the parallel part flow velocity was 200 mm / second, and the injection / cooling was 20/20 seconds. A Charpy impact test piece (no notch) having a length of 80 mm, a width of 10 mm and a thickness of 4 mm was cut out from the parallel part of the obtained multipurpose test piece. The obtained Charpy test piece was stored in a moisture-proof aluminum bag. Using this Charpy test piece, Charpy impact strength (no notch) with a residence time of 20 minutes was measured according to ISO179. From the obtained value and the Charpy Charpy impact strength (no notch) measured by the method described in (5) above (no residence time), the retention strength retention was measured by the following (Equation 3).

  The manufacturing method of the raw material used for the Example and the comparative example is shown below.

Reference Example 1 (A1-1) Polyamide 6
ε-Caprolactam was charged into the polymerization can, distilled water was added so that the water content was 45% by weight, the inside of the polymerization can was replaced with N ₂ , and the temperature was raised to 260 ° C. Next, polymerization was performed while controlling pressure at 1.7 MPa for 1 hour, and then discharging and cutting were performed to obtain (A1-1) polyamide 6. The relative viscosity measured by the method described in (1) to (2) above was 2.7, and the melting point was 225 ° C.

Reference Example 2 (A1-2) Polyamide 6/66
Was charged equimolar salt 15 wt% and 85 wt% .epsilon.-caprolactam of hexamethylene diamine and adipic acid in a polymerization vessel, replacing distilled water as the water content of 45 wt% was added, the inside of polymerization vessel with N ₂ Then, the temperature was raised to 260 ° C. Subsequently, the pressure was controlled and polymerized at 1.7 MPa for 1 hour, and then discharged and cut to obtain (A1-2) polyamide 6/66. The relative viscosity measured by the method described in (1) to (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 hexamethylene diamine and adipic acid, 15% by weight of equimolar salt of hexamethylene diamine and isophthalic acid, and 10% by weight of ε-caprolactam are put into a polymerization can, and the water content becomes 45% by weight. As described above, distilled water was added and the inside of the polymerization can was replaced with N ₂ , and then the temperature was raised to 260 ° C. Then, after pressure suppression and polymerization at 1.7 MPa for 1 hour, the mixture was discharged and cut to obtain (A1-3) polyamide 66 / 6I / 6. The relative viscosity measured by the method described in (1) to (2) above was 2.7, and the melting point was 227 ° C.

Reference Example 4 (A2) Polyamide 66
Was charged equimolar salt of hexamethylenediamine and adipic acid in a 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 280 ° C.. Subsequently, after pressure suppression and polymerization at 1.7 MPa for 1 hour, the mixture was discharged and cut to obtain (A2) polyamide 66. The relative viscosity measured by the method described in (1) to (2) above was 2.8, and the melting point was 265 ° C.

Reference Example 5 (A3) Polyamide 12
It was charged 12-aminododecanoic acid 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.. Subsequently, after pressure suppression / polymerization at 1.7 MPa for 1 hour, the mixture was discharged and cut to obtain (A3) polyamide 12. The relative viscosity measured by the method described in (1) to (2) above was 2.8, and the melting point was 275 ° C.

Reference Example 6 (B1) Glass fiber (urethane surface treatment)
Polyester non-yellowing urethane resin emulsion (HADE-290H, manufactured by ADEKA) and γ-aminopropyltriethoxysilane (KBM-903, manufactured by Shin-Etsu Chemical Co., Ltd.), 0.6% by weight in terms of solid content % Was added and deionized water was added to produce a glass fiber sizing agent. A glass fiber sizing agent was applied to the surface of an E glass filament having a diameter of 13 μm, and 2000 bundles were formed into glass fiber strands, which were wound around a paper tube to form a cake. A glass chopped strand was obtained by cutting the glass fiber strand from the cake to a length of 3 mm while drying.

Reference Example 7 (B2) Glass fiber (acid-based surface treatment)
Prepared by blending 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. Ionized water was added to produce a glass fiber sizing agent. The glass fiber sizing agent was applied to the surface of an E glass filament having a diameter of 13 μm, and 2000 bundles were bundled to form glass fiber strands, which were wound around a paper tube to form a cake. A glass chopped strand was obtained by cutting the glass fiber strand from the cake to a length of 3 mm while 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)
Sachtleben Chemie: Sachtolith HD-S (average particle size 0.30 to 0.35 μm) 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 with Mohs hardness of 5 or more (C ′) Titanium oxide (Mohs hardness 7)
Ishihara Sangyo Co., Ltd. product: “Taipeku” (registered trademark) CR-61 (average particle size 0.21 μm) was used.
(D) Phosphorus heat-resistant agent manufactured by BASF: (D1) IRGAFOS168 (organic type) was used.
(E) Hindered phenol antioxidant manufactured by 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)
BASF: (F1) Chimasorb 2020FDL was used.

Examples 1-13, Comparative Examples 1-9
The polyamide resin, white pigment, phosphorus heat-resistant agent, hindered phenol-based antioxidant and weathering agent shown in Tables 1 and 2 were fed in from the top feeder of a twin-screw extruder (manufactured by 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 among the polyamide resins to be used + 20 ° C. A screw arrangement with two screw extruders and two kneading zones was set, and the screw rotation speed was set to 265 rpm. The fibrous reinforcement shown in Tables 1-2 is side-fed from between the first kneading zone close to the original loading side and the second kneading zone on the downstream side, and melt-kneaded to form a strand-shaped gut, After cooling with a cooling bath, it was granulated with a cutter to obtain pellets. The result evaluated by the said evaluation method using the obtained pellet is shown to Tables 1-2.

Claims (7)

(A) 100 parts by weight of polyamide resin, (B) 5 to 100 parts by weight of fibrous reinforcement, (C) 0.1 to 9 parts by weight of white pigment having a Mohs hardness of less than 5, (D) phosphorus heat resistance A polyamide resin composition containing 0.2-2 parts by weight of an agent and 0.2-2 parts by weight of (E) a hindered phenol antioxidant, and molding a Type-IA multipurpose test piece of ISO 3167 standard, A polyamide resin composition having a lightness L ^* in the CIELAB space of 60 or more when measured using a D65 light source. The (A) polyamide resin contains (A1) a polyamide resin having a melting point of 190 ° C. or higher and 240 ° C. or lower as measured by differential scanning calorimetry (DSC), and (A) the total amount of polyamide resin is 100% by weight. The polyamide resin composition according to claim 1, comprising 60% by weight or more of a polyamide resin having a melting point measured by calorimetry (DSC) of 190 ° C or higher and 240 ° C or lower. (C) The polyamide resin composition according to claim 1 or 2, wherein the white pigment contains zinc sulfide. The polyamide resin composition according to any one of claims 1 to 3, wherein the fibrous reinforcing material (B2) contains glass fibers containing polyurethane on the surface. An ISO 3167 standard Type-IA multi-purpose test piece is molded, and an ISO strip test piece obtained by cutting from a parallel part of the multi-purpose test piece is irradiated with xenon arc lamp and quartz / # with an irradiance of 150 ± 10 W / m ^2. Charpy impact strength (without notch) when measured according to ISO 179 after weathering for 480 hours using a 295 filter (inside / outside) under conditions of black panel temperature of 63 ± 3 ° C. and no rain, 65 kJ / a m ² or more, any of claims 1 to 4, the Charpy impact strength retention rate before and after weathering treatment ((Charpy impact strength before Charpy impact strength / weathering process after weathering treatment) × 100) is 95% or more A polyamide resin composition as described above. A molded article comprising the polyamide resin composition according to any one of claims 1 to 5. The molded article according to claim 6, which is an automobile exterior part, a home appliance exterior part or a daily necessities part.