JP2006291118A - Polyamide resin composition for parts in automobile cooling and air-conditioning systems - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyamide resin composition for parts in automobile cooling and air-conditioning systems that is markedly improved in endurance against antifreeze under high temperature conditions and resistance to calcium chloride without impairing excellent characteristics of a glass fiber reinforced polyamide resin. <P>SOLUTION: The polyamide resin composition for parts in automobile cooling and air-conditioning systems comprises (A) a polyamide resin having a concentration of amino end groups of not less than 60 mequivalent/kg, (B) a polypropylene resin having a density of not less than 0.906 g/cm<SP>3</SP>as measured in accordance with JIS K7112, (C) a modified polypropylene resin having 0.5-2 wt.% maleic anhydride grafted thereon, (D) a glass fiber and (E) a heat stabilizer wherein the total amount of the components (B) and (C) is 10-40 wt.% based on the total amount of the components (A), (B) and (C); the blending amount of the component (D) is 20-40 wt.% based on the total amount of the components (A), (B), (C) and (D); and the blending amount of the component (E) is 0.1-3.0 pts.wt. based on 100 pts.wt. of the total amount of the components (A), (B), (C) and (D). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a polyamide resin composition for automotive cooling and air conditioning parts. More specifically, the present invention relates to a polyamide resin composition for automotive cooling and air-conditioning parts having excellent mechanical properties, heat aging resistance, durability against automobile antifreeze at 100 ° C. to 150 ° C., and calcium chloride resistance.

In the automobile field, metal parts have been made resinous for light weight and rational assembly. Among them, polyamide resin reinforced with glass fiber is attracting attention as a material for automotive parts that come into contact with antifreeze liquids such as radiator tanks and water valves because of its excellent mechanical properties, heat resistance, oil resistance, and toughness, and has been used for a long time. There is.
However, the conventional glass fiber reinforced polyamide resin has a drawback that the strength decreases due to contact with the antifreeze solution for a long time in a high temperature atmosphere, and the temperature of the cooling water tends to be further accelerated in the future. There was a problem in using it for cooling air conditioning parts materials. In order to remedy this drawback, attempts have been made to extend the degradation life against antifreeze by increasing the glass fiber concentration of the glass fiber reinforced polyamide resin and improving the initial mechanical properties. In addition to increasing the weight of parts due to the increase in glass fiber, there is a disadvantage that not only goes against the trend of reducing the weight of automobiles, but also a new problem arises in that the appearance of the molded product deteriorates and the number of post-processing steps increases. It was not always a satisfactory material.

  Further, Patent Documents 1 to 5 aim to obtain a polyamide material for cooling air-conditioning parts having excellent antifreeze resistance or physical properties at the time of water absorption, and a polyamide resin is blended with a modified polypropylene resin, which is reinforced with glass fibers. Polyamide resin compositions have been proposed, but these proposals are certainly effective in improving antifreeze resistance, but mechanical properties, particularly thermal rigidity, are not sufficient, and cooling mounted in the automobile engine room It was not always a satisfactory material as a polyamide resin material for air conditioning parts.

Japanese Patent Publication No. 61-026939 Japanese Patent No. 2678615 Japanese Patent No. 2630799 Japanese Patent No. 2649406 Japanese Patent No. 2695490

  An object of the present invention is to provide a polyamide resin composition for automotive cooling and air-conditioning parts that has significantly improved durability against antifreeze at 100 ° C. to 150 ° C. and calcium chloride resistance without impairing the excellent properties of glass fiber reinforced polyamide resin. It is to provide.

  As a result of intensive studies to solve the above problems, the present inventors have blended a polyamide resin having a high amino group concentration with a high-density polypropylene resin, a modified polypropylene resin grafted with maleic anhydride, glass fiber, and a heat stabilizer. It has been found that the resin composition can achieve the above-mentioned problems, and the present invention has been achieved.

That is, the present invention
[1] (A) a polyamide resin having an amino end group of 60 meq / kg or more,
(B) a polypropylene resin having a density measured by JIS K7112 of 0.906 g / cm ³ or more,
(C) a modified polypropylene resin grafted with 0.5 to 2% by weight of maleic anhydride,
A polyamide resin composition comprising (D) glass fiber, and (E) a heat stabilizer,
The total amount of (B) and (C) is 10 to 40% by weight with respect to the total amount of (A), (B) and (C), and the blending amount of (D) is (A), (B) and ( 20 to 40% by weight with respect to the total amount of C) and (D), and the amount of (E) is 0 with respect to 100 parts by weight of the total amount of (A), (B), (C) and (D) .1 to 3.0 parts by weight, and
The polyamide resin composition for automotive cooling and air-conditioning parts, wherein the blending amount of (C) is 10 to 40% by weight with respect to the total amount of (B) and (C),

[2] (A) The polyamide resin composition for automotive cooling and air-conditioning parts according to [1], wherein the amino terminal group of the polyamide resin is 70 meq / kg or more,
[3] (B) Polyamide resin composition for automotive cooling and air-conditioning parts according to [1] or [2], wherein the flexural modulus measured by JIS K6758 of the polypropylene resin is 1500 MPa or more,
[4] Any of [1] to [3], wherein (E) the heat stabilizer is one or more selected from a hindered phenol heat stabilizer, a sulfur heat stabilizer and a hindered amine heat stabilizer. A polyamide resin composition for automotive cooling and air-conditioning parts,
It is.

  The molded product obtained by molding the polyamide resin composition for automotive cooling and air-conditioning parts of the present invention has a high temperature of 100 ° C. to 150 ° C. without impairing mechanical properties such as tensile strength and bending elastic modulus of the glass fiber reinforced polyamide resin. The molded article has excellent durability against calcium antifreeze and calcium chloride resistance, and further improved heat aging resistance.

The present invention is described in detail below.
As the polyamide resin (A) of the present invention, hexamethylene diamine, decamethylene diamine, dodecamethylene diamine, 2,2,4- or 2,4,4-trimethylhexamethylene diamine, 1,3- or 1,4- Aliphatic, alicyclic or aromatic diamines such as bis (aminomethyl) cyclohexane, bis (p-aminocyclohexylmethane), m- or p-xylylenediamine, and adipic acid, suberic acid, sebacic acid, cyclohexane Manufactured from polyamide resin, 6-aminocaproic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid produced from aliphatic, alicyclic or aromatic dicarboxylic acid such as dicarboxylic acid, terephthalic acid, isophthalic acid Polyamide resins such as ε-caprolactam and ω-dodecalactam Examples thereof include polyamide resins produced from cutam, copolymerized polyamide resins composed of these components, and mixtures of these polyamide resins. Specific examples of the polyamide resin include polyamide 6, polyamide 66, polyamide 610, polyamide 612, and the like. Among these, polyamide 66 and a mixture of polyamide 66 and polyamide 612 are preferable from the viewpoint of excellent calcium chloride resistance and rigidity at high temperatures.

The polyamide resin used in the present invention is a polyamide resin having an amino end group concentration of 60 meq / kg or more, preferably in the range of 70 to 130 meq / kg. The amino terminal group of the polyamide resin can be measured, for example, by a method of potentiometric titration of a polyamide solution dissolved in phenol with hydrochloric acid. By using a polyamide resin having an amino end group of 60 meq / kg or more, a decrease in molecular weight with respect to a high-temperature antifreeze was remarkably suppressed, and surface treatment was performed on unsaturated carboxylic acid grafted on polypropylene or its anhydride and glass fiber. It is only possible to improve antifreeze resistance (tensile strength after immersion in antifreeze, suppression of molecular weight reduction), calcium chloride resistance and mechanical properties by firmly bonding with coupling agents containing acid anhydrides. Become.

Moreover, the carboxyl group of the polyamide resin is not particularly limited, but those having a range of usually 120 meq / kg or less can be used, and a more preferred range is 30 to 60 meq / kg.
The polyamide resin of the present invention preferably has a relative viscosity of 1.0 or more as measured with 98% sulfuric acid in accordance with JIS K6810, and particularly preferably in the range of 2.0 to 4.0 because of excellent mechanical properties. .

  For the production of the polyamide resin in the present invention, for example, a method of performing polycondensation by a melt polymerization method, a solid phase polymerization method, a bulk polymerization method, a solution polymerization method, or a combination of these can be used. Also, a method such as solution polymerization or interfacial polymerization may be used. Among these, a method by melt polymerization or a combination of melt polymerization and solid phase polymerization is preferably used from the viewpoint of economy. In order to obtain the polyamide resin of the present invention having a high concentration of amino end groups, in these known polymerization methods, a method of adding a diamine compound during polymerization of the polyamide resin and increasing the ratio of amine to carboxylic acid should be used. Can do.

  The polyamide resin of the present invention preferably contains a copper element for preventing heat deterioration. A compound containing copper element (hereinafter referred to as a copper compound) can be added in any of the processes for producing the resin composition of the present invention. However, in order to allow the copper compound to efficiently exist in the polyamide resin phase. Addition in the polyamide polymerization step is preferred. Examples of the copper compound added to the polyamide resin include copper chloride, copper bromide, copper fluoride, copper iodide, copper thiocyanate, copper nitrate, copper acetate, naphthenic copper, copper caprate, copper laurate, and stearic acid. Examples thereof include copper, acetylacetone copper, copper (I) oxide, and copper (II) oxide. Particularly preferred in the present invention are copper halides such as copper iodide, and copper acetate.

The addition amount of the copper compound is preferably 5 ppm or more, more preferably in the range of 10 to 5000 ppm, based on the copper element in the copper compound with respect to the polyamide resin.
The copper compound is more preferably used in combination with an iodine compound. Examples of the iodine compound include potassium iodide, magnesium iodide, and ammonium iodide. Although iodine may be used alone, potassium iodide is more preferable. The iodine compound preferably has a gram atomic ratio of iodine element to copper element ([iodine] / [copper]) of 5 to 30, and more preferably 10 to 25.

  Next, as the polypropylene resin as the component (B) used in the present invention, in addition to propylene homopolymer, ethylene, butene can be used as long as it contains propylene in an amount of 50 mol% or more, preferably 80% or more. -1, pentene-1, hexene-1, 4-methylpentene-1 or other α-olefins or other random or block copolymers. In the case of a copolymer, ethylene is particularly preferable as the α-olefin copolymerized with propylene, but it is most preferable to use a homopolymer excellent in mechanical properties, thermal properties, and durability.

Density of polypropylene resin, as measured by JIS K-7112, and a 0.906 g / cm ³ or more, preferably in the range of 0.908~0.920g / cm ^3. By blending a polypropylene resin having a density of 0.906 g / cm ³ or more, a composition having good mechanical properties such as tensile strength, tensile strength and flexural modulus after immersion in the antifreeze solution can be obtained. As a method for producing such a polypropylene-based resin, a method for obtaining a polypropylene-based resin having a density in the above range by polymerization, or a density by adding a nucleating agent to a polypropylene-based resin having a density of less than 0.906 g / cm ^3. And obtaining a polypropylene resin having a density in the above range.

Any nucleating agent may be used as long as it improves the crystallinity of the polypropylene resin. Typical nucleating agents include metal salts of aromatic carboxylic acids, sorbitol derivatives, organic phosphates, aromatics. Examples thereof include organic nucleating agents such as group amide compounds and inorganic nucleating agents such as talc and boron nitride, but are not particularly limited thereto.
Polypropylene resin is usually used in the presence of a titanium trichloride catalyst or a titanium halide catalyst supported on a carrier such as magnesium chloride and an alkylaluminum compound in a polymerization temperature range of 0 to 100 ° C. and a polymerization pressure of 100 atm or less. It is obtained by carrying out the polymerization in the range of At this time, a chain transfer agent such as hydrogen may be added to adjust the molecular weight of the polymer. Either a batch type or a continuous type can be used as a polymerization method. Solution polymerization in a solvent such as butane, pentane, hexane, heptane, octane, slurry polymerization, bulk polymerization in a monomer without solvent, and gas A gas phase polymerization method in the form of a monomer can be applied.

  In addition to the polymerization catalyst described above, an electron donating compound can be used as an internal donor component or an external donor component as the third component in order to increase the isotacticity and polymerization activity of the resulting polypropylene resin. As these electron donating compounds, known compounds can be used, for example, ester compounds such as ε-caprolactone / methyl methacrylate, ethyl benzoate, methyl toluate, triphenyl phosphite, tributyl phosphite. Phosphoric acid esters such as hexamethylphosphoric triamide, alkoxy diester compounds, aromatic monocarboxylic acid esters, aromatic alkyl alkoxy silanes, aliphatic hydrocarbon alkoxy silanes, various ether compounds, various Examples include alcohols and various phenols.

Polypropylene resin has a density, as measured by JIS K-7112, and a 0.906 g / cm ³ or more, preferably be in the range of 0.908~0.920g / cm ^3, those having any melting point Even if it exists, it can be used in the present invention, but considering that the resulting resin composition exhibits durability as a heat resistant material, it is preferable to use a polypropylene resin having a melting point of 155 ° C. or higher.
As for the crystallinity of the polypropylene resin of the present invention, a highly crystalline polypropylene resin in which the proportion of a crystal phase composed of a propylene homopolymer portion determined by free induction decay (FID) of pulse NMR is 90% or more is preferably used.

The proportion of the crystalline phase of the propylene homopolymer portion in the present invention is a change in magnetization after applying a 90-degree pulse based on spin-spin relaxation by utilizing different motility between the crystalline portion and the amorphous portion by a known pulsed NMR method. It can be obtained from induction decay (FID). Specifically, a solid state polypropylene resin was measured at a temperature of 40 ° C., a proton resonance frequency of 20 Hz, a pulse time of 4 μsec, and a total of three times using pulse NMR (Bruker PC-120). From the shorter relaxation time, the crystalline phase and the amorphous phase are assigned, the crystalline phase is regressed with a Gaussian curve, the amorphous phase is regressed with a Lorentzian curve, and the respective peak heights are SA1 and SA2. From the formula R ₁₂ = {100 × (SA1−SA2) × F} ÷ {(SA1−SA2) × F + SA2}, the ratio of crystal phases can be obtained. Here, R ₁₂ is the ratio of the measured crystal phase of the propylene homopolymer portion, and F is a correction coefficient obtained from the strength ratio when salad oil and polymethyl methacrylate are used as a standard sample.

The melt flow rate at a test temperature of 230 ° C. and a test load of 21.2 N measured by JIS K7210 of the polypropylene resin of the present invention is preferably 0.1 to 60 g / 10 min, more preferably 10 to 50 g / 10 min. . When the melt flow rate is within this range, a composition having an excellent balance between fluidity and mechanical properties can be obtained.
The polypropylene resin used in the present invention preferably has a flexural modulus measured according to JIS K6758 of 1500 MPa to 2200 MPa, more preferably 1800 MPa to 2200 MPa. By using a polypropylene resin in this range, a composition having good strength and elastic modulus can be obtained.

Next, the polypropylene resin used in the modified polypropylene resin grafted with 0.5 to 2% by weight of maleic anhydride as the component (C) of the present invention is the unmodified polypropylene resin as the component (B) of the present invention. A copolymer or a homopolymer similar to those described above may be modified, or a polypropylene resin other than the component (B) may be modified. The density, crystallinity, and melt flow rate of the polypropylene resin used as the component (C) are not particularly limited, but the density measured by JIS K-7112 is 0.860 to 0.920 g / cm ³ , respectively, The proportion of the crystal phase composed of the propylene homopolymer determined by free induction decay (FID) is 80% or more, the melt flow rate is 0.1 to 200 g at a test temperature of 230 ° C. and a test load of 21.2 N measured according to JIS K7210. A polypropylene resin in the range of / 10 min is preferred.

Modification of the modified polypropylene resin of the present invention can be carried out by either a solution method or a melt kneading method. In the case of the melt-kneading method, polypropylene resin, maleic anhydride and a catalyst are put into an extruder, a biaxial kneader, etc., heated to a temperature of 150 to 250 ° C., and kneaded while melting and degassing. In the case of a solution method, the above starting materials are dissolved in an organic solvent such as xylene, and stirring is performed at a temperature of 80 to 140 ° C. In any case, a normal radical polymerization catalyst can be used as the catalyst, such as benzoyl peroxide, lauroyl peroxide, ditertiary butyl peroxide, acetyl peroxide, tertiary butyl peroxybenzoic acid, dicumyl peroxide, Peroxides such as peroxybenzoic acid, peroxyacetic acid, and tertiary butyl peroxypivalate, and diazo compounds such as azobisisobutyronitrile are preferred. The addition amount of the catalyst is about 1 to 10 parts by weight with respect to 100 parts by weight of maleic anhydride.
The maleic anhydride graft amount of the modified polypropylene resin of the present invention is required to be 0.5 to 2% by weight, and preferably 0.8 to 1.2% by weight. If the amount of grafting is within this range, the compatibility of the composition is good and the mechanical properties are excellent.

  The glass fiber which is the component (D) used in the present invention may be any glass fiber as long as it is used as a reinforcing material for the polyamide resin. From the viewpoint of handling properties when the glass fiber is melt-mixed with the polyamide resin, the glass fiber is used. Chopped short fibers having a fiber length of 1 to 10 mm and an average glass fiber diameter of 8 to 25 μm are preferred. A particularly preferable glass fiber shape is a glass fiber having a fiber length of 2 to 7 mm and an average fiber diameter of 8 to 15 μm from the viewpoint of the reinforcing effect and the glass fiber dispersibility. By using glass fibers in this range, it is possible to obtain a composition having an excellent balance between the mechanical properties, which are the effects of the present invention, and the appearance of the molded product.

Moreover, 10-50 are preferable and, as for the aspect ratio of the glass fiber contained in a polyamide resin, 20-40 are more preferable. If the aspect ratio of the glass fiber contained is less than 10, the improvement rate of the mechanical properties cannot be expected so much, and if it exceeds 50, the glass fiber tends to appear on the surface of the molded product, which may deteriorate the appearance of the molded product. The aspect ratio of the glass fiber referred to here is a value obtained by dividing the weight average fiber length of the glass fiber by the fiber diameter.
Further, the glass fiber is preferably surface-treated with a bundling agent for polyamide resin (this includes a bundling component for so-called sizing and a surface treatment component for adhesion between the polyamide resin). The sizing agent used here is mainly composed of a copolymer of maleic anhydride and an unsaturated monomer and a silane coupling agent. Most preferred are those comprising a copolymer of an acid and an unsaturated monomer and an amino group-containing silane coupling agent as main constituents. Moreover, there is no problem even if an acrylic acid copolymer or a urethane polymer is used in combination.

  Specific examples of the copolymer of maleic anhydride and unsaturated monomer constituting the sizing agent include styrene, α-methylstyrene, butadiene, isoprene, chloroprene, 2,3-dichlorobutadiene, and 1,3-pentadiene. And a copolymer of an unsaturated monomer such as cyclooctadiene and maleic anhydride. Among them, a copolymer of butadiene or styrene and maleic anhydride is particularly preferable. Further, these monomers may be used in combination of two or more. For example, they may be used by blending such as using a mixture of maleic anhydride / butadiene copolymer and maleic anhydride / styrene copolymer. It doesn't matter. The copolymer of maleic anhydride and unsaturated monomer preferably has an average molecular weight of 2,000 or more. Further, the ratio of maleic anhydride and unsaturated monomer is not particularly limited. Furthermore, in addition to a copolymer of maleic anhydride and an unsaturated monomer, an acrylic acid copolymer or a urethane polymer may be used in combination.

  As the silane coupling agent which is another component constituting the sizing agent of the present invention, any silane coupling agent which is usually used for the surface treatment of glass fibers can be used. Specifically, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane Aminosilane coupling agents such as N-β (aminoethyl) γ-aminopropyltriethoxysilane; γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyl Epoxysilane coupling agents such as triethoxysilane; γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-methacryloxypropyltriethoxysilane, etc. Metacloxisila System coupling agent; vinyltrimethoxysilane, vinyltriethoxysilane, and the like vinyltris (beta-methoxyethoxy) vinylsilane coupling agents such as silane.

  Two or more of these coupling agents can be used in combination. Of these, aminosilane coupling agents are most preferred because of their affinity for polyamide resin, and among them, γ-aminopropyltriethoxysilane and N-β (aminoethyl) γ-aminopropyltriethoxysilane are most preferred. The proportion of the maleic anhydride copolymer and the silane coupling agent used is preferably the proportion of 0.01 to 20 parts by weight of the latter with respect to 100 parts by weight of the former that gives a relatively good balance of physical properties. Normally, maleic anhydride copolymer and silane coupling agent are mixed in an aqueous solvent and used as a sizing agent. If necessary, surfactants, lubricants, softeners, antistatic agents, etc. may be added. Also good.

  The sizing agent is used by adhering to the glass fiber surface in the step of processing the glass into a fiber or after the processing, but when this is dried, the coating composed of the copolymer and the coupling agent becomes a glass fiber. Formed on the surface. At this time, the final adhesion amount of the sizing agent after drying is preferably in the range of 0.1 to 2 parts by weight per 100 parts by weight of the glass fiber from the viewpoint of the sizing property of the glass fiber. If it is within this range, when blended with the polyamide resin, the so-called pills in which the glass fibers are entangled with each other are not generated, and the appearance of the molded product that is generated because the glass fibers are firmly bundled is poor. Nor. A more preferable sizing agent adhesion amount is in the range of 0.2 to 1.0 part by weight per 100 parts by weight of glass fiber. Here, the sizing agent adhesion amount is measured as a loss on ignition after 60 minutes of heating of the glass fiber, and is obtained in accordance with JIS R3420.

The heat stabilizer which is the component (E) of the present invention is usually a phosphorus heat stabilizer, a hindered phenol heat stabilizer, a sulfur heat stabilizer, a lactone heat stabilizer, or a hindered amine used in polypropylene resins. A system heat stabilizer or the like can be used.
Examples of the hindered phenol heat stabilizer include 3,9-bis {2- [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy] -1,1-dimethylethyl}. -2,4,8,10-tetraoxaspiro [5.5] undecane, reaction product of p-cresol and isobutylene, 3- (4'-hydroxy-3'-5'-di-tert-butylphenyl) Propionic acid-n-octadecyl, 4,4′-thiobis (6-tert-butyl-3-methylphenol), tetrakis [methylene-3- (3 ′, 5′-di-tert-butyl-4′-hydroxyphenyl) ) Propionate] methane, 1,6-hexanediol-bis [3 (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 2,2-thio [die Tilbis-3 (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], diethyl [[3,5-bis (1,1-dimethylethyl) -4-hydroxyphenyl] methyl] phosphonate, 2, Reaction of 4-dichlorobenzaldehyde, 3,6-dioxaoctamethylene bis [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionate], o-cresol, 1-octanethiol, paraformaldehyde Product, 6-methylheptyl = 3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, dichlorobis (η (5) -cyclopentadienyl) titanium (IV), 2,2′- Methylenebis (6-tert-butyl) -p-cresol, 1,3,5-trimethyl-2,4,6-to Sus (3,5-di-t-butyl-4-hydroxybenzyl) benzene, styrenated phenol, 4,4′-butylidenebis (6-tert-butyl-3-methylphenol), methylenebis (nonylcresol), 2 -Tert-butyl-6- (3-tert-butyl-2-hydroxy-5-methylbenzyl) -4-methylphenyl acrylate, 1,3,5-tris (3 ', 5'-di-tert-butyl -4-hydroxybenzyl) isocyanuric acid, 6- (4-hydroxy-3-5-di-tert-butylanilino) -2,4-bisoctylthio-1,3,5-triazine, 1,3,5-tris (4-tert-Butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanuric acid, 1,1,3-tris (2-methyl-4-hydro Ci-5-tert-butylphenyl) butane, N, N′-bis-3- (3′5′di-tert-butyl-4′-hydroxyphenyl) propionylhexamethylenediamine, and the like. A preferred hindered phenol-based heat stabilizer is 3,9-bis {2- [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy] -1,1-dimethylethyl} -2. 4,8,10-tetraoxaspiro [5.5] undecane.

  Examples of the sulfur-based heat stabilizer include pentaerythritol tetrakis (3-lauryl thiopropionate), dilauryl thiodipropionate, distearyl thiodipropionate, 2,2-bis ({[3- (dodecylthio ) Propanoyl] oxy} methyl) propane-1,3-diyl = bis [3- (dodecylthio) propanoate], 2-mercaptobenzimidazole, bis [2-methyl-4- {3-n-alkyl (C12 or C14) Thiopropionyloxy} -5-tert-butylphenyl] sulfide, and the like. Among them, a preferred sulfur stabilizer is pentaerythritol tetrakis (3-laurylthiopropionate).

Examples of the hindered amine heat stabilizer include aldol-α-naphthylamine, phenyl-β-naphthylamine, phenyl-α-naphthylamine, alkylated diphenylamine, octylated diphenylamine, acetone, diphenylamine reactant, N · N-diphenyl-P. -Phenylenediamine, N.I. N-di-β-naphthyl-P-phenylenediamine, phenylcyclohexyl-P-phenylenediamine, N-phenyl-N ′-(1-methylhexyl) -P-phenylenediamine, N-phenyl-N ′-(1 , 3, dimethylbutyl) -P-phenylenediamine, NN′di (1,4, dimethylbenzyl) -P-phenyldiamine, diallyl-P-phenylenediamine, diallyl-P-phenylenediamine, 4,4 ′. -Bis (α, α-dimethylbenzyl) diphenylamine and the like can be mentioned, and among these, a preferred hindered amine heat stabilizer is 4,4′-bis (α, α-dimethylbenzyl) diphenylamine.

Particularly preferably, a hindered phenol heat stabilizer, a sulfur heat stabilizer and a hindered amine heat stabilizer are used in combination, and the hindered phenol heat stabilizer is 5 to 20% by weight, and the sulfur heat stabilizer. Most preferably, they are used in combination at a composition ratio of 30 to 40% by weight and hindered amine heat stabilizer 40 to 65% by weight.
The total blending ratio of the polypropylene resin as the component (B) and the modified propylene resin as the component (C) of the present invention is based on the total amount of the (A) polyamide resin and (B) and (C). 10 to 40% by weight, preferably 15 to 35% by weight. When the total blending ratio of the component (B) and the component (C) is within this range, the antifreeze solution at a high temperature of 100 ° C. to 150 ° C. of the present invention without impairing mechanical properties such as tensile strength and flexural modulus. Sufficient improvement effect of calcium chloride and calcium chloride resistance.
Furthermore, the glass fiber which is (D) component of this invention is 20 to 40 weight% with respect to the total amount of (A), (B), (C), and (D) component, Preferably, it is 25-35. % By weight. When the blending ratio of the component (D) is within this range, the mechanical properties of the molded product are not impaired, and sufficient molding fluidity of the glass fiber reinforced resin composition can be secured, and a good molded product appearance can be obtained.

The heat stabilizer which is the component (E) of the present invention is in the range of 0.1 to 3.0 parts by weight with respect to 100 parts by weight of the total amount of the components (A), (B), (C) and (D). Preferably, it is 0.3 to 1.5 parts by weight. When the blending ratio of the component (E) is within this range, good heat aging resistance can be obtained without bleeding out of the heat stabilizer during good molding.
Furthermore, the ratio of (C) component with respect to the sum total of (B) component and (C) component is 10 to 40 weight%, Preferably it is 15 to 35 weight%. If the blending ratio of the component (C) is 10% by weight or more, the maleic anhydride that can be reacted with the polyamide resin grafted to the modified propylene can be sufficiently secured, so that the molded product does not peel off and the molding is performed. Since the fluidity is not impaired, a good appearance of the molded product can be obtained. When the blending ratio of the component (C) is 40% by weight or less, good calcium chloride resistance can be obtained without impairing mechanical properties.

The automobile cooling and air-conditioning parts referred to in the present invention are automobile parts that come into contact with an antifreeze mainly composed of ethylene glycol. For example, automobiles such as a radiator tank, a water pump housing, a water pump impeller, a water valve, a radiator pipe, and a heater tank. Underhood parts.
When obtaining the polyamide resin composition for automotive cooling and air-conditioning parts of the present invention, there are no particular restrictions on the blending, mixing, and kneading methods and their order, and a commonly used mixer such as a Henschel mixer, tumbler, ribbon blender, etc. What is necessary is just to mix. As the kneader, a single-screw or twin-screw extruder is usually used. Examples of the melt-kneading method include a method of kneading each component at once, a method of melt-kneading a part of the components, and further melt-kneading with the remaining components. Also, a method in which some components are melt-kneaded to form pellets, the remaining components are melt-kneaded to form pellets, and they are blended is also possible. Especially, the method of feeding glass fiber in the state which the resin component fuse | melted is preferable in the meaning which leaves glass fiber length in a long state in a composition. A molded article made of the resin composition of the present invention is usually produced by first producing pellets made of the resin composition of the present invention with an extruder, and then molding the pellets into an arbitrary shape by compression molding, injection molding, extrusion molding, or the like. To obtain a desired resin product.
When the molded product of the present invention is injection molded, for example, it is preferable to mold at a molding temperature of 250 ° C. to 310 ° C. and a mold temperature of 40 ° C. to 120 ° C.

EXAMPLES Next, although an Example demonstrates this invention still in detail, this invention is not limited to it.
The raw materials, abbreviations and test methods used in the examples are as follows.
[1] Raw material PA (A): Polyamide 66 produced in Production Example 1
PA (B): Polyamide 66 produced in Production Example 2
PA (C): Polyamide 612 produced in Production Example 3

PP (A): Polypropylene resin
Density (JIS K7112) 0.908 [g / cm ³ ]
MFR 12 [g / 10min]
Flexural modulus 2060 [MPa]
PP (B): Polypropylene resin
Density (JIS K7112) 0.901 [g / cm ³ ]
MFR 12 [g / 10min]
Flexural modulus 1400 [MPa]
PP (C): Polypropylene resin
Density (JIS K7112) 0.908 [g / cm ³ ]
MFR 40 [g / 10min]
Flexural modulus 2080 [MPa]

mPP (A): maleic anhydride-modified polypropylene produced in Production Example 4 mPP (B): maleic anhydride-modified polypropylene GF produced in Production Example 5: surface-treated glass fiber
ECS03T275H made by Nippon Electric Glass
10 μmφ, 3 mm cut length TS1: hindered phenol heat stabilizer
3,9-bis {2- [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy] -1,1-dimethylethyl} -2,4,8,10-tetraoxaspiro [5.5] Undecane
GA-80 manufactured by Sumitomo Chemical
TS2: Sulfur-based heat stabilizer
Pentaerythritol tetrakis (3-laurylthiopropionate)
TP-D made by Sumitomo Chemical
TS3: Hindered amine heat stabilizer
4,4'-bis (α, α-dimethylbenzyl) diphenylamine
Nouchi CD from Ouchi Shinsei Chemical

[2] Evaluation method (1) Amino terminal group of polyamide raw material 3 g of polyamide pellets used as a raw material were accurately weighed to 0.1 mg in a weighing bottle, and about 2 was added to 100 ml of 90% phenol aqueous solution previously measured in a 200 ml beaker. It was dissolved with stirring over time. The solution is then subjected to potentiometric titration with a 1 / 40N aqueous hydrochloric acid solution to determine the neutralization point, and the amount (X) [ml] of the 1 / 40N aqueous hydrochloric acid solution required for this is determined. Further, titration was performed in the same manner as described above using only a phenol aqueous solution that did not dissolve the pellet, the neutralization point was determined, the amount (Y) [ml] of the 1/40 normal hydrochloric acid aqueous solution required for this was determined, and the following formula The amino end group was calculated.
Amino terminal group [m equivalent / kg] = ((f × (XY)) / G) × 100/4
Here, f represents a factor of an N / 40 hydrochloric acid aqueous solution, and G represents an anhydrous sample weight (unit: g).

(2) Tensile strength and flexural modulus Using a Nissei Plastic PS40E injection molding machine, a 3 mm thick ASTM type 1 was molded under molding conditions of a screw rotation speed of 200 rpm and a resin temperature of 290 ° C. A sample for measuring physical properties was used, and tensile strength and flexural modulus were measured according to ASTM D638 and D790, respectively.
(3) Tensile strength after immersion in antifreeze solution Using a Toshiba Machine IS150E injection molding machine, with a screw rotation speed of 200 rpm, a resin temperature of 290 ° C., and a mold temperature of 80 ° C., a thickness of 3 mm and a width shown in FIG. A dumbbell-shaped test piece having a shape shown in FIG. 2 is formed by molding a molded product having a length of 130 mm and a length of 130 mm, and the gate portion being in one piece of a flat plate, and the direction perpendicular to the resin flow direction is the longitudinal direction of the dumbbell piece. Cut out. The positions of the flat plate and the cut specimen are shown in FIG. A 50% aqueous solution of an antifreeze (Toyota Genuine Long Life Coolant) containing ethylene glycol as a main component was heated to 130 ° C., and the test piece was immersed and taken out for 400 hours, and then a tensile strength test was performed.

(4) Calcium chloride resistance A 50% aqueous solution of antifreeze (Toyota Genuine Long Life Coolant) is heated to 80 ° C using a flat-cut dumbbell-shaped test piece that has the same shape as the test piece whose tensile strength was measured after immersion in antifreeze. This was immersed in 1 hour, immersed in 80 ° C. water for 4 hours, and allowed to stand in an atmosphere of 80 ° C. and 60% RH for 185 hours, and then the calcium chloride cycle test was started. In the calcium chloride cycle test, gauze was wound around the marked portion of the test piece, and a 35 wt% calcium chloride aqueous solution was infiltrated. Thereafter, the test piece is attached to a creep tester (manufactured by Yasuda Seiki Seisakusho; model 145-PC 6-unit creep tester), loaded with 60% of the tensile rupture stress at 100 ° C, and 1 hour in an atmosphere of 100 ° C. Dried. After drying, the test piece was taken out from the creep tester, washed with water, and then immersed in water at 80 ° C. for 25 minutes. The crack which arose in the test piece after repeating this operation 30 times was observed visually. This was evaluated according to the following criteria.
○: No crack occurred ×: Crack occurred

(5) Appearance of molded product Using Toshiba Machine IS150E molding machine, using a flat plate mold of 130mm x 130mm x 3mm, molding stroke of 62mm, cushion stroke under molding conditions of screw speed 200rpm and resin temperature 290 ° C The surface appearance of the central part of a test piece molded at 10 mm, primary pressure switching position 15 mm, mold temperature of 80 ° C. and primary pressure time of 1.2 seconds is measured using a handy gloss meter IG-320 manufactured by Horiba, Ltd. according to JIS-K7105. The glossiness was measured.
(6) Heat aging resistance Using a flat cut dumbbell-shaped test piece having the same shape as the test piece whose tensile strength after immersion in the antifreeze solution was measured, the tensile strength after 1000 hours exposure in an oven at 150 ° C. was measured. The strength retention was determined when the tensile strength measured in (zero) time was 100%.

[Production Example 1]
PA (A): Manufacture of polyamide 66 5 L autoclave containing 2.50 kg of equimolar salt of adipic acid and hexamethylenediamine, 21.5 g of hexamethylenediamine, 9 g of copper iodide, 150 g of potassium iodide and 2.5 kg of pure water Stir well and stir well. After sufficient N ₂ substitution, the temperature was raised from room temperature to 220 ° C. over about 1 hour with stirring. Under the present circumstances, although the internal pressure became 18 kg / cm < ² > -G by the natural pressure by the water vapor | steam in an autoclave, it continued further heating, removing water out of a reaction system so that it might not become a pressure more than 18 kg / cm < ² > -G. When the internal temperature reached 260 ° C. after 2 hours, the heating was stopped, the autoclave discharge valve was closed, and the system was cooled to room temperature over about 8 hours. After cooling, the autoclave was opened, and about 2 kg of polymer was taken out and ground. The obtained pulverized polymer was placed in a 10 L evaporator and subjected to solid phase polymerization at 200 ° C. for 10 hours under a N ₂ stream. The terminal amino group concentration of the polyamide obtained by solid phase polymerization was 80 meq / kg of polymer, and the sulfuric acid viscosity measured according to JIS K6810 using 98% sulfuric acid was 2.8. This polyamide contained 30 ppm of copper element, and the gram atomic ratio of iodine element to copper element ([iodine / copper]) was 19.

[Production Example 2]
PA (B): Production of polyamide 66 2.50 kg of equimolar salt of adipic acid and hexamethylenediamine, 9 g of copper iodide, 150 g of potassium iodide and 2.5 kg of pure water were charged into a 5 L autoclave and stirred well. . After sufficient N ₂ substitution, the temperature was raised from room temperature to 220 ° C. over about 1 hour with stirring. Under the present circumstances, although the internal pressure became 18 kg / cm < ² > -G by the natural pressure by the water vapor | steam in an autoclave, it continued further heating, removing water out of a reaction system so that it might not become a pressure more than 18 kg / cm < ² > -G. When the internal temperature reached 260 ° C. after 2 hours, the heating was stopped, the autoclave discharge valve was closed, and the system was cooled to room temperature over about 8 hours. After cooling, the autoclave was opened, and about 2 kg of polymer was taken out and ground. The obtained pulverized polymer was placed in a 10 L evaporator and subjected to solid phase polymerization at 200 ° C. for 10 hours under a N ₂ stream. The terminal amino group concentration of the polyamide obtained by solid phase polymerization was 45 meq / kg of polymer, and the sulfuric acid viscosity measured according to JIS K6810 using 98% sulfuric acid was 2.8. This polyamide contained 30 ppm of copper element, and the gram atomic ratio of iodine element to copper element ([iodine / copper]) was 19.

[Production Example 3]
PA (C): Manufacture of polyamide 612 2.50 kg of equimolar salt of dodecanedioic acid and hexamethylenediamine, 9 g of copper iodide, 150 g of potassium iodide and 2.5 kg of pure water were placed in a 5 L autoclave and stirred well. did. After sufficient N ₂ substitution, the temperature was raised from room temperature to 220 ° C. over about 1 hour with stirring. Under the present circumstances, although the internal pressure became 18 kg / cm < ² > -G by the natural pressure by the water vapor | steam in an autoclave, it continued further heating, removing water out of a reaction system so that it might not become a pressure more than 18 kg / cm < ² > -G. When the internal temperature reached 260 ° C. after 2 hours, the heating was stopped, the autoclave discharge valve was closed, and the system was cooled to room temperature over about 8 hours. After cooling, the autoclave was opened, and about 2 kg of polymer was taken out and ground. The obtained pulverized polymer was placed in a 10 L evaporator and subjected to solid phase polymerization at 200 ° C. for 10 hours under a N ₂ stream. The terminal amino group concentration of the polyamide obtained by solid phase polymerization was 65 meq / kg of polymer, and the sulfuric acid viscosity measured according to JIS K6810 using 98% sulfuric acid was 2.1. This polyamide contained 30 ppm of copper element, and the gram atomic ratio of iodine element to copper element ([iodine / copper]) was 19.

[Production Example 4]
MPP (A): Production of modified polypropylene α, α′-bis-t dissolved in 1.3 parts by weight of maleic anhydride and a small amount of acetone with respect to 100 parts by weight of polypropylene (Novatech PP MA3 manufactured by Nippon Polypro) -0.065 parts by weight of butyl peroxide-p-diisopropylbenzene were blended in a Henschel mixer. This blend was extruded and pelletized at 230 ° C. using a TEM35 extruder to obtain a modified polypropylene. The pellets were pulverized and Soxhlet extracted with acetone for 12 hours. This was dried and pressed, and maleic anhydride was quantified by infrared absorption spectrum. As a result, it was found that 1.0% by weight of maleic anhydride was added.

[Production Example 5]
MPP (B): Production of modified polypropylene α, α′-bis-t dissolved in 0.35 parts by weight of maleic anhydride and a small amount of acetone with respect to 100 parts by weight of polypropylene (Novatech PP MA3 manufactured by Nippon Polypro) -0.013 parts by weight of butyl peroxide-p-diisopropylbenzene were blended in a Henschel mixer. This blend was extruded and pelletized at 230 ° C. using a TEM35 extruder to obtain a modified polypropylene. The pellets were pulverized and Soxhlet extracted with acetone for 12 hours. This was dried and pressed, and maleic anhydride was quantified by infrared absorption spectrum. It was found that 0.3% by weight of maleic anhydride was added.

[Examples 1-2 and Comparative Examples 1-2]
Using a TEM35φ twin screw extruder manufactured by Toshiba Machine Co., Ltd. (set temperature: 290 ° C., screw rotation speed: 300 rpm), the types of polyamide resins and thermal stabilizers shown in Table 1 from the top feed port provided at the most upstream part of the extruder A predetermined amount blended with a weight feeder, and a blend of a predetermined amount of the polypropylene resin and modified polypropylene resin shown in Table 1 is blended using a separate weight feeder, The glass fiber is supplied from the side feed port on the downstream side of the supply and the extruder (the resin supplied from the top feed port is sufficiently melted), and the melt-kneaded product extruded from the die head is cooled in a strand shape. And pelletizing to obtain polyamide resin composition pellets. The resulting composition pellets were molded and evaluated by the methods described above. The composition and evaluation results are shown in Table 1.

[Example 3]
(A) Polyamide resin composition pellets were obtained in the same manner as in Example 1 except that PA (A) and PA (C) were blended in advance at the ratio shown in Table 1 as the component polyamide resin and then fed. . The resulting composition pellets were molded and evaluated by the methods described above. The composition and evaluation results are shown in Table 1.
[Comparative Example 3]
A composition was obtained in the same manner as in Example 1 except that the polypropylene resin as the component (B) and the modified polypropylene resin as the component (C) were not blended. The resulting composition pellets were molded and evaluated by the methods described above. The composition and evaluation results are shown in Table 2.

[Examples 4 to 5 and Comparative Examples 4 to 7]
A composition was obtained in the same manner as in Example 1 except that the components (A) to (E) were supplied at the blending ratios shown in Table 1 or Table 2. The resulting composition pellets were molded and evaluated by the methods described above. The compositions and evaluation results are shown in Table 1 for Examples 4-5 and Table 2 for Comparative Examples 4-7.
From this result, it is understood that the tensile strength and calcium chloride resistance after immersion in the antifreeze solution are greatly improved by blending the polypropylene resin and the modified polypropylene resin in specific ratios.

[Comparative Example 8]
The composition was obtained and evaluated in the same manner as in Example 1 except that the heat stabilizer as the component (E) was not blended. The composition and evaluation results are shown in Table 2.
It can be seen from this result that the heat aging resistance is remarkably improved by adding a heat stabilizer.
[Comparative Example 9]
The composition was obtained and evaluated in the same manner as in Example 1 except that the type of the modified polypropylene as the component (C) was changed and the polypropylene resin as the component (B) was not blended. The composition and evaluation results are shown in Table 2.
From this result, it is understood that the modified polypropylene has a low modification rate, and the mechanical properties, the tensile strength after immersion in the antifreeze solution, the calcium chloride resistance, and the appearance of the molded product are lowered by not blending the high density polypropylene.

  The molded product obtained by molding the polyamide resin composition for automotive cooling and air-conditioning parts of the present invention has excellent mechanical properties, heat aging resistance, durability against automobile antifreeze at 100 ° C. to 150 ° C., calcium chloride resistance Therefore, it is the most suitable material for automotive parts that come into contact with high-temperature antifreeze such as radiator tanks, water pumps, water pump impellers, water valves, radiator pipes, and heater tanks that require strict reliability.

It is (a) front view and (b) side view of the flat molded product which cuts out the dumbbell-type test piece used for evaluation of the strength after immersion in antifreeze, calcium chloride resistance, and heat aging resistance. It is the (a) front view and (b) side view of the dumbbell-type test piece used for evaluation of the strength after immersion in antifreeze, calcium chloride resistance, and heat aging resistance. It is explanatory drawing which takes out a dumbbell-type test piece from the flat molded object of FIG.

Explanation of symbols

1 Flat molded product 2 Gate 3 Dumbbell-shaped test piece

Claims (4)

(A) a polyamide resin having an amino end group of 60 meq / kg or more,
(B) a polypropylene resin having a density measured by JIS K7112 of 0.906 g / cm ³ or more,
(C) a modified polypropylene resin grafted with 0.5 to 2% by weight of maleic anhydride,
A polyamide resin composition comprising (D) glass fiber, and (E) a heat stabilizer,
The total amount of (B) and (C) is 10 to 40% by weight with respect to the total amount of (A), (B) and (C), and the blending amount of (D) is (A), (B) and ( 20 to 40% by weight with respect to the total amount of C) and (D), and the amount of (E) is 0 with respect to 100 parts by weight of the total amount of (A), (B), (C) and (D) .1 to 3.0 parts by weight, and
The polyamide resin composition for automotive cooling and air-conditioning parts, wherein the blending amount of (C) is 10 to 40% by weight based on the total amount of (B) and (C).   (A) The polyamide resin composition for automotive cooling and air-conditioning parts according to claim 1, wherein the amino terminal group of the polyamide resin is 70 meq / kg or more.   (B) The polyamide resin composition for automotive cooling and air-conditioning parts according to claim 1 or 2, wherein the flexural modulus measured by JIS K6758 of the polypropylene resin is 1500 MPa or more.   (E) The heat stabilizer is one or more selected from a hindered phenol-based heat stabilizer, a sulfur-based heat stabilizer, and a hindered amine-based heat stabilizer. The polyamide resin composition for automotive cooling air-conditioning parts described in 1.

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