JP5728969B2 - Polyamide resin composition for engine cooling water system parts and engine cooling water system parts using the same - Google Patents

Description

  The present invention relates to a reinforced polyamide resin composition suitable for molding automobile engine cooling water system parts. More specifically, it is excellent in calcium chloride resistance, antifreeze resistance, low water absorption, etc., which are suitably used for applications such as radiator tank parts, water pump parts, etc., particularly in applications where they are used in contact with cooling water in the engine room. The present invention relates to a polyamide resin composition for engine cooling water system parts.

For automotive parts, especially plastic parts used in the engine room, the environment of use is severe as engine performance increases, engine coolant temperature increases due to higher output, and engine room temperatures increase. It has become something. In cold regions, a large amount of anti-road anti-freezing agents such as calcium chloride and zinc chloride are sprayed as snow melting agents, and engine parts are also exposed to these agents. In the conventional nylon 6 and nylon 66, since the deterioration of the resin proceeds under such a severe use environment, various improvement measures have been taken.
For example, a method of using a glass fiber having a specific fine fineness treated with a specific surface treatment agent as a reinforcing material in nylon 66 (Patent Document 1), a method of blending a high melting point polyamide having a melting point of 300 ° C. or higher such as nylon 6T ( For example, Patent Documents 2 and 3) are proposed, and there are attempts to use high melting point polyamide such as nylon 6T. However, these methods do not satisfy all of moldability, fluidity, low water absorption, durability and the like, and there is room for improvement.

Japanese Patent No. 3271328 Japanese Patent No. 3985316 JP 2002-114905 A

  The present invention seeks to provide a reinforced polyamide resin composition suitable for engine cooling water system parts having not only lower water absorption, excellent dimensional stability and chemical resistance, but also excellent durability such as long-term hot water resistance. Is.

  In order to achieve the above object, the inventor has intensively studied the composition of the polyamide, and as a result, has completed the present invention.

That is, the present invention has the following configurations (1) to (5).
(1) (a) A fibrous reinforcing agent (100) based on 100 parts by mass of a copolymerized polyamide resin (A) composed of 55 to 75 mol% of hexamethylene terephthalamide units and 45 to 25 mol% of undecanamide units. B) is a composition containing 20 to 150 parts by mass, and the composition satisfies the following (A) and (B): A polyamide resin composition for engine cooling water system parts.
(A) Saturated water absorption (%) in hot water of 80 ° C. is 3.0% or less (b) Tensile strength reduction rate (%) after immersion in boiling water for 2000 hours is 30% or less (2) Copolymerized polyamide resin ( A) is obtained from (c) a structural unit obtained from an equimolar molar salt of a diamine other than the structural unit of (a) and a dicarboxylic acid, or an aminocarboxylic acid or lactam other than the structural unit of (b). The polyamide resin composition for engine cooling water system parts as described in (1) above, containing a unit of up to 20 mol%.
(3) The polyamide resin composition for engine cooling water system parts according to the above (1) or (2), wherein the terminal carboxyl group concentration of the copolymerized polyamide resin (A) is 80 to 120 equivalent / ton.
(4) The engine cooling water system component according to any one of (1) to (3), wherein the polyamide resin composition has a melting point of 300 to 330 ° C. and a temperature rising crystallization temperature (Tc1) of 90 to 120 ° C. Polyamide resin composition.
(5) Engine cooling water system parts obtained by using the polyamide resin composition according to any one of (1) to (4).
(6) The engine coolant system component is any one of a radiator tank component, a coolant reserve tank, a water pipe, a water inlet pipe, a water outlet pipe, a water pump housing, a water pump impeller, and a water valve. Engine cooling water system parts.

  The polyamide resin composition of the present invention is a reinforced polyamide resin composition using a specific copolymerized polyamide resin that is excellent in moldability and processability during injection molding in addition to high heat resistance and low water absorption, and has long-term resistance. Since it is excellent in durability such as boiling water, it is suitable for engine cooling water system parts.

  The polyamide resin composition of the present invention is intended for use in engine cooling water system parts. Examples of the engine cooling water system parts include radiator tank parts, coolant reserve tanks, water pipes, water inlet pipes, water outlet pipes, water pump housings, water pump impellers, water pump parts such as water valves, and the like.

The polyamide resin composition of the present invention is based on 100 parts by mass of a copolymerized polyamide resin (A) comprising (a) 55 to 75 mol% of hexamethylene terephthalamide units and (b) 45 to 25 mol% of undecanamide units. The composition contains 20 to 150 parts by mass of the fibrous reinforcing agent (B), and the composition is a polyamide resin composition for engine cooling water system parts that satisfies the following (A) and (B): Features.
(A) Saturated water absorption (%) in hot water at 80 ° C. is 3.0% or less (b) Tensile strength reduction rate (%) after immersion in boiling water for 2000 hours is 30% or less

  The copolymerized polyamide resin (A) is blended to realize excellent moldability in addition to high heat resistance, fluidity and low water absorption, and the component (a) corresponding to polyamide 6T and polyamide 11 And a conventional 6T nylon (for example, polyamide 6T6I made of terephthalic acid / isophthalic acid / hexamethylenediamine, polyamide made of terephthalic acid / adipic acid / terephthalic acid) 6T66, polyamide 6T6I66 composed of terephthalic acid / isophthalic acid / adipic acid / hexamethylenediamine, polyamide 6T / M-5T composed of terephthalic acid / hexamethylenediamine / 2-methyl-1,5-pentamethylenediamine, terephthalic acid / hexa Consists of methylenediamine / ε-caprolactam Polyamide 6T6 disadvantage superabsorbent which is of) not only is greatly improved, has a feature of excellent durability of the reinforcing effect of the fibrous reinforcing agent. Furthermore, since it has a flexible long-chain aliphatic skeleton derived from the polyamide 11 component, it also has a feature that it is easy to ensure fluidity.

  The component (a) corresponds to 6T nylon obtained by co-condensation polymerization of hexamethylenediamine (6) and terephthalic acid (T) in an equimolar amount, and specifically, the following formula (I) It is represented by

  The component (a) is a main component of the copolymerized polyamide resin (A) and has a role of imparting excellent heat resistance, mechanical properties, slidability, and the like to the copolymerized polyamide resin (A). The blending ratio of the component (a) in the copolymerized polyamide (A) is 55 to 75 mol%, preferably 60 to 70 mol%, more preferably 62 to 68 mol%. When the blending ratio of the component (a) is less than the above lower limit, 6T nylon, which is a crystal component, is subject to crystal inhibition by the copolymerization component, which may lead to a decrease in moldability and high temperature characteristics. Since melting | fusing point becomes high too much and there exists a possibility of decomposing | disassembling at the time of a process, it is unpreferable.

  The component (b) corresponds to 11 nylon obtained by polycondensation of 11-aminoundecanoic acid or undecane lactam, and is specifically represented by the following formula (II).

  The component (b) is for improving water absorption and fluidity, which is a drawback of the component (a). The moldability is adjusted by adjusting the melting point and the temperature rising crystallization temperature of the copolymerized polyamide resin (A). It has the role of improving, the role of reducing the water absorption rate to improve the trouble caused by changes in physical properties and dimensional changes at the time of water absorption, and the role of improving the fluidity at the time of melting by introducing a flexible skeleton. The blending ratio of the component (b) in the copolymerized polyamide resin (A) is 45 to 25 mol%, preferably 40 to 30 mol%, more preferably 38 to 32 mol%. When the blending ratio of the component (b) is less than the above lower limit, the melting point of the copolymerized polyamide resin (A) is not sufficiently lowered, the moldability may be insufficient, and the water absorption rate of the obtained resin is reduced. The effect is insufficient, and there is a risk of instability of physical properties such as deterioration of mechanical properties upon water absorption. When the above upper limit is exceeded, the melting point of the copolymerized polyamide resin (A) is too low, the crystallization speed is slow, the moldability may be adversely affected, and the amount of the component (a) corresponding to 6T nylon This is not preferable because there is a risk that mechanical properties and heat resistance may be insufficient.

  In addition to the components (a) and (b), the copolymerized polyamide resin (A) is (c) a structural unit obtained from an equivalent molar salt of diamine and dicarboxylic acid other than the structural unit of (a) above, or You may copolymerize the structural unit obtained from aminocarboxylic acid or lactam other than the structural unit of said (b) at maximum 20 mol%. Component (c) has a role of imparting other characteristics not obtainable with 6T nylon or 11 nylon to copolymerized polyamide resin (A), or further improving the characteristics obtained with 6T nylon or 11 nylon. Specific examples include the following copolymerization components. Examples of the diamine component include 1,2-ethylenediamine, 1,3-trimethylenediamine, 1,4-tetramethylenediamine, 5-pentamethylenediamine, 2-methyl-1,5-pentamethylenediamine, 1,6-hexa Methylenediamine, 1,7-heptamethylenediamine, 1,8-octamethylenediamine, 1,9-nonamethylenediamine, 2-methyl-1,8-octamethylenediamine, 1,10-decamethylenediamine, 1,11 -Undecamethylenediamine, 1,12-dodecamethylenediamine, 1,13-tridecamethylenediamine, 1,16-hexadecamethylenediamine, 1,18-octadecamethylenediamine, 2,2,4 (or 2, 4,4) -aliphatic diamines such as trimethylhexamethylenediamine, piperazine, Cyclohexanediamine, bis (3-methyl-4-aminohexyl) methane, bis- (4,4′-aminocyclohexyl) methane, cycloaliphatic diamines such as isophoronediamine, metaxylylenediamine, paraxylylenediamine, Examples thereof include aromatic diamines such as paraphenylenediamine and metaphenylenediamine, and hydrogenated products thereof. As the dicarboxylic acid component, the following dicarboxylic acids or acid anhydrides can be used. Examples of the dicarboxylic acid include terephthalic acid, isophthalic acid, orthophthalic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 4,4′-diphenyldicarboxylic acid, and 2,2′-diphenyldicarboxylic acid. 4,4'-diphenyl ether dicarboxylic acid, 5-sulfonic acid sodium isophthalic acid, 5-hydroxyisophthalic acid and other aromatic dicarboxylic acids, fumaric acid, maleic acid, succinic acid, itaconic acid, adipic acid, azelaic acid, sebacic acid 1,11-undecanedioic acid, 1,12-dodecanedioic acid, 1,14-tetradecanedioic acid, 1,18-octadecanedioic acid, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1 , 2-cyclohexanedicarboxylic acid, 4-methyl-1,2-cyclohexa Dicarboxylic acids, such as aliphatic or alicyclic dicarboxylic acids such as dimer acid. Further, lactams such as ε-caprolactam and 12-lauryl lactam, and aminocarboxylic acids having a structure in which they are ring-opened can be used.

  Specific examples of the component (c) include polycaproamide (polyamide 6), polydodecanamide (polyamide 12), polytetramethylene adipamide (polyamide 46), polyhexamethylene adipamide (polyamide 66), polyun Decamethylene adipamide (polyamide 116), polymetaxylylene adipamide (polyamide MXD6), polyparaxylylene adipamide (polyamide PXD6), polytetramethylene sebamide (polyamide 410), polyhexamethylene sebacamide (Polyamide 610), polydecamethylene adipamide (polyamide 106), polydecamethylene sebamide (polyamide 1010), polyhexamethylene dodecamide (polyamide 612), polydecamethylene dodecamide (polyamide 1012), polyhexamethyle Isophthalamide (polyamide 6I), polytetramethylene terephthalamide (polyamide 4T), polypentamethylene terephthalamide (polyamide 5T), poly-2-methylpentamethylene terephthalamide (polyamide M-5T), polyhexamethylene hexahydroterephthalamide (Polyamide 6T (H)), Polynonamethylene terephthalamide (Polyamide 9T), Polydecamethylene terephthalamide (Polyamide 10T), Polyundecamethylene terephthalamide (Polyamide 11T), Polydodecamethylene terephthalamide (Polyamide 12T), Polybis (3-Methyl-4-aminohexyl) methane terephthalamide (polyamide PACMT), polybis (3-methyl-4-aminohexyl) methane isophthalamide (Polymer) Amide PACMI), polybis (3-methyl-4-amino-hexyl) methane dodecamide (polyamide PACM12), and the like polybis (3-methyl-4-amino-hexyl) methane tetradecanoyl bromide (polyamide PACM14). These may be copolymerized alone or in combination of multiple components. Any copolymerization technique such as random copolymerization, block copolymerization, and graft copolymerization may be used.

  Among the structural units, examples of a preferable component (c) include polyhexamethylene adipamide for imparting high crystallinity to the copolymerized polyamide resin (A), and poly (polyethylene) for imparting further low water absorption. Examples include decamethylene terephthalamide and polydodecanamide. The blending ratio of the component (c) in the copolymerized polyamide resin (A) is preferably up to 20 mol%, more preferably 10 to 20 mol%. When the proportion of the component (c) is less than the above lower limit, the effect of the component (c) may not be sufficiently exhibited. When the proportion exceeds the above upper limit, the amount of the essential component (a) or component (b) is small. Therefore, the originally intended effect of the copolymerized polyamide resin (A) may not be sufficiently exhibited, which is not preferable.

  Examples of the catalyst used for producing the copolymerized polyamide resin (A) include phosphoric acid, phosphorous acid, hypophosphorous acid or a metal salt, ammonium salt and ester thereof. Specific examples of the metal species of the metal salt include potassium, sodium, magnesium, vanadium, calcium, zinc, cobalt, manganese, tin, tungsten, germanium, titanium, and antimony. As the ester, ethyl ester, isopropyl ester, butyl ester, hexyl ester, isodecyl ester, octadecyl ester, decyl ester, stearyl ester, phenyl ester and the like can be added. Moreover, it is preferable to add alkali compounds, such as sodium hydroxide, potassium hydroxide, and magnesium hydroxide, from a viewpoint of melt retention stability improvement.

  The relative viscosity (RV) measured at 20 ° C. in 96% concentrated sulfuric acid of the copolymerized polyamide resin (A) is 0.4 to 4.0, preferably 1.0 to 3.0, more preferably 1.5. ~ 2.5. Examples of a method for setting the relative viscosity of the polyamide within a certain range include a means for adjusting the molecular weight.

  The copolymerized polyamide resin (A) can adjust the end group amount and the molecular weight of the polyamide by adjusting the molar ratio between the amino group amount and the carboxyl group to carry out polycondensation or adding a terminal blocking agent. it can.

  In the case of using a terminal blocking agent, the raw material is charged, the polymerization is started, the polymerization is late, or the polymerization is completed. The end capping agent is not particularly limited as long as it is a monofunctional compound having reactivity with the amino group or carboxyl group at the end of the polyamide, but acid anhydrides such as monocarboxylic acid or monoamine, phthalic anhydride, Monoisocyanates, monoacid halides, monoesters, monoalcohols and the like can be used. Examples of the end capping agent include aliphatic monoacids such as acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, lauric acid, tridecanoic acid, myristic acid, palmitic acid, stearic acid, pivalic acid, and isobutyric acid. Alicyclic monocarboxylic acids such as carboxylic acid and cyclohexanecarboxylic acid, benzoic acid, toluic acid, α-naphthalenecarboxylic acid, β-naphthalenecarboxylic acid, methylnaphthalenecarboxylic acid, phenylacetic acid and other aromatic monocarboxylic acids, maleic anhydride Acid, phthalic anhydride, acid anhydrides such as hexahydrophthalic anhydride, methylamine, ethylamine, propylamine, butylamine, hexylamine, octylamine, decylamine, stearylamine, dimethylamine, diethylamine, dipropylamine, dibutylamine, etc. Aliphatic monoamines, Examples thereof include alicyclic monoamines such as cyclohexylamine and dicyclohexylamine; aromatic monoamines such as aniline, toluidine, diphenylamine and naphthylamine.

The copolymerized polyamide resin (A) preferably has a terminal carboxyl group concentration of 80 to 120 equivalent / ton. Within this range, the reinforcing effect of the blended glass fibers is specifically expressed, and the reinforced polyamide resin composition having excellent long-term boiling water resistance of the present invention can be obtained. When the terminal carboxyl group concentration exceeds 120 equivalents / ton, not only gelation and deterioration are promoted during melt residence, but also problems such as coloring and hydrolysis may occur in the use environment. If it is less than tons, the effect of this invention will fall.
On the other hand, when compounding a reactive compound such as maleic acid-modified polyolefin, it is preferable to adjust the terminal carboxyl group concentration and / or terminal amino group concentration as appropriate in accordance with the reactivity and reactive group.

  The copolymerized polyamide resin (A) can be produced by a conventionally known method. For example, hexamethylene diamine, terephthalic acid, which is a raw material monomer of the component (a), and 11 a raw material monomer of the component (b). -Aminoundecanoic acid or undecanactactam, and if necessary (c) a structural unit obtained from an equimolar salt of a diamine other than the structural unit of (a) and a dicarboxylic acid, an aminocarboxylic acid other than the structural unit of (b) Alternatively, it can be easily synthesized by co-condensation of lactam. The order of the copolycondensation reaction is not particularly limited, and all the raw material monomers may be reacted at once, or a part of the raw material monomers may be reacted first, followed by the remaining raw material monomers. Although the polymerization method is not particularly limited, the process from raw material preparation to polymer production may proceed in a continuous process. After the oligomer is produced once, the polymerization is advanced by an extruder or the like in another process, or the oligomer is solidified. A method of increasing the molecular weight by phase polymerization may be used. By adjusting the charging ratio of the raw material monomer, the proportion of each structural unit in the copolymerized polyamide to be synthesized can be controlled.

  In the polyamide resin composition of the present invention, the copolymerized polyamide resin (A) is preferably 25 to 85% by mass, more preferably 40 to 75% by mass. If the proportion of the copolymerized polyamide resin (A) is less than the above lower limit, the mechanical strength is lowered, and if it exceeds the above upper limit, the blending amount of the fibrous reinforcing agent (B) is insufficient and a desired effect is obtained. It becomes difficult to be.

  Examples of the fibrous reinforcing agent (B) include glass fiber, carbon fiber, boron fiber, ceramic fiber, and metal fiber. Examples of the acicular reinforcing agent include potassium titanate whisker, aluminum borate whisker, and zinc oxide. Examples include whisker, calcium carbonate whisker, magnesium sulfate whisker, and wollastonite. As the glass fiber, chopped strands or continuous filament fibers having a length of 0.1 mm to 100 mm can be used. As the cross-sectional shape of the glass fiber, a glass fiber having a circular cross section and a non-circular cross section can be used. The diameter of the circular cross-section glass fiber is 20 μm or less, preferably 15 μm or less, more preferably 10 μm or less. Further, a glass fiber having a non-circular cross section is preferred from the viewpoint of physical properties and fluidity. Non-circular cross-sectional glass fibers include those that are substantially oval, substantially oval, and substantially bowl-shaped in a cross section perpendicular to the length direction of the fiber length, and have a flatness of 1.5 to 8. It is preferable. Here, the flatness is assumed to be a rectangle with the smallest area circumscribing a cross section perpendicular to the longitudinal direction of the glass fiber, the length of the long side of the rectangle is the major axis, and the length of the short side is the minor axis. It is the ratio of major axis / minor axis. The thickness of the glass fiber is not particularly limited, but the minor axis is about 1 to 20 μm and the major axis is about 2 to 100 μm. Moreover, the glass fiber becomes a fiber bundle, and the thing of the chopped strand shape cut | disconnected by about 1-20 mm of fiber length can use it preferably. Furthermore, in order to increase the surface reflectance of the polyamide resin composition, it is preferable that the difference in refractive index from the copolymerized polyamide resin is large. It is preferable to do.

  The proportion of the fibrous reinforcing agent (B) is 20 to 150 parts by mass, preferably 40 to 130 parts by mass with respect to 100 parts by mass of the copolymerized polyamide resin (A). When the ratio of the fibrous reinforcing agent (B) is less than the above lower limit, the mechanical strength of the molded product is lowered, and when it exceeds the upper limit, the moldability tends to be lowered.

  Non-fibrous or non-needle fillers (C) that can be used as necessary include reinforcing fillers, conductive fillers, magnetic fillers, flame retardant fillers, heat conductive fillers, heat yellowing suppression fillers, etc., depending on the purpose. Specifically, glass beads, glass flakes, glass balloons, silica, talc, kaolin, mica, alumina, hydrotalcite, montmorillonite, graphite, carbon nanotubes, fullerene, indium oxide, tin oxide, iron oxide, oxidation Magnesium, aluminum hydroxide, magnesium hydroxide, calcium hydroxide, red phosphorus, calcium carbonate, lead zirconate titanate, barium titanate, aluminum nitride, boron nitride, zinc borate, barium sulfate, and non-acicular wollast Knight, potassium titanate, aluminum borate Arm, magnesium sulfate, zinc oxide, calcium carbonate, and the like. These fillers may be used not only alone but also in combination of several kinds. Among these, talc is preferable because Tc1 is lowered and moldability is improved. The addition amount of the filler may be selected as an optimum amount, but it is possible to add up to 50 parts by mass with respect to 100 parts by mass of the copolymerized polyamide resin (A), but the mechanical strength of the resin composition From this viewpoint, 0.1 to 20 parts by mass is preferable, and 1 to 10 parts by mass is more preferable. In addition, in order to improve the affinity with the polyamide resin, the fibrous reinforcing agent and the filler are preferably combined with the coupling agent at the time of the organic treatment or the coupling agent treatment, or the melt compound. Any of silane coupling agents, titanate coupling agents, and aluminum coupling agents may be used, and among them, aminosilane coupling agents and epoxysilane coupling agents are particularly preferable.

In the polyamide resin composition of the present invention, the copolymerized polyamide resin (A) has a specific composition, the terminal carboxyl group concentration is a high acid value of 80 to 120 equivalent / ton, and the saturated water absorption rate in hot water at 80 ° C. (% ) Is a composition having a low water absorption of 3.0% or less, the interaction with the fibrous reinforcing agent (B) causes (b) 30% reduction in tensile strength (%) after immersing in boiling water for 2000 hours. % Of boiling water resistance can be easily expressed.
When the terminal carboxyl group concentration is 85 to 110 equivalent / ton and the saturated water absorption (%) in 80 ° C. hot water is 2.5% or less, (b) tensile after immersion in boiling water for 2000 hours Long-term boiling water resistance with a strength reduction rate (T)% of 25% or less can also be exhibited.
The copolymerized polyamide resin (A) in the present invention can maintain high strength for a longer period in the reinforced polyamide resin composition of the present invention, although the saturated water absorption is higher than that of the polyamide 9T. it can.

  Various additives of the conventional polyamide resin composition for engine cooling water system parts can be used for the polyamide resin composition of the present invention. Additives include stabilizers, impact modifiers, flame retardants, mold release agents, slidability improvers, colorants, plasticizers, crystal nucleating agents, and polyamides other than polyamide polyamides other than copolymerized polyamide resins (A) A thermoplastic resin etc. are mentioned.

  Stabilizers include organic antioxidants such as hindered phenol antioxidants, sulfur antioxidants, phosphorus antioxidants, heat stabilizers, light stabilizers such as hindered amines, benzophenones, and imidazoles. Examples include ultraviolet absorbers, metal deactivators, and copper compounds. Copper compounds include cuprous chloride, cuprous bromide, cuprous iodide, cupric chloride, cupric bromide, cupric iodide, cupric phosphate, cupric pyrophosphate, Copper salts of organic carboxylic acids such as copper sulfide, copper nitrate, and copper acetate can be used. Further, as a component other than the copper compound, an alkali metal halide compound is preferably contained. Examples of the alkali metal halide compound include lithium chloride, lithium bromide, lithium iodide, sodium fluoride, sodium chloride, bromide. Examples thereof include sodium, sodium iodide, potassium fluoride, potassium chloride, potassium bromide, potassium iodide and the like. These additives may be used alone or in combination of several kinds. The addition amount of the stabilizer may be an optimal amount, but it is possible to add a maximum of 5 parts by mass with respect to 100 parts by mass of the copolymerized polyamide resin (A).

  The polyamide resin composition of the present invention may be polymer blended with a polyamide having a composition different from that of the copolymerized polyamide resin (A). The polyamide having a composition different from that of the copolymerized polyamide of the present invention is not particularly limited, but polycaproamide (polyamide 6), polyundecanamide (polyamide 11), polydodecanamide (polyamide 12), polytetramethylene adipamide (Polyamide 46), polyhexamethylene adipamide (polyamide 66), polymetaxylylene adipamide (polyamide MXD6), polyparaxylylene adipamide (polyamide PXD6), polytetramethylene sebacamide (polyamide 410), Polyhexamethylene sebamide (polyamide 610), polydecamethylene adipamide (polyamide 106), polydecamethylene sebamide (polyamide 1010), polyhexamethylene dodecamide (polyamide 612), polydecamethylene dodecamide (polyamide) Amide 1012), polyhexamethylene terephthalamide (polyamide 6T), polyhexamethylene isophthalamide (polyamide 6I), polytetramethylene terephthalamide (polyamide 4T), polypentamethylene terephthalamide (polyamide 5T), poly-2-methylpenta Methylene terephthalamide (polyamide M-5T), polyhexamethylene hexahydroterephthalamide (polyamide 6T (H)), poly 2-methyl-octamethylene terephthalamide, polynonamethylene terephthalamide (polyamide 9T), polydecamethylene terephthalamide (Polyamide 10T), polyundecamethylene terephthalamide (polyamide 11T), polydodecamethylene terephthalamide (polyamide 12T), polybis (3-methyl) 4-aminohexyl) methane terephthalamide (polyamide PACMT), polybis (3-methyl-4-aminohexyl) methane isophthalamide (polyamide PACMI), polybis (3-methyl-4-aminohexyl) methane dodecamide (polyamide PACM12) , Polybis (3-methyl-4-aminohexyl) methanetetradecamide (polyamide PACM14), polyalkyl ether copolymerized polyamide or the like, or these copolymerized polyamides may be used alone or in combination. Of these, polyamide 66, polyamide 6T66, and the like may be blended with polyamide 10T derivative for imparting further low water absorption, etc., in order to increase the crystallization speed and improve the moldability. The addition amount of polyamide having a composition different from that of the copolymerized polyamide resin (A) may be selected, but a maximum of 50 parts by mass can be added to 100 parts by mass of the copolymerized polyamide resin (A). It is. Of course, the polyamide resin contained in the polyamide resin composition of the present invention may be only the copolymerized polyamide (A).

  A thermoplastic resin other than polyamide having a composition different from that of the copolymerized polyamide resin (A) may be added to the polyamide resin composition of the present invention. Polymers other than polyamide include polyphenylene sulfide (PPS), liquid crystal polymer (LCP), aramid resin, polyetheretherketone (PEEK), polyetherketone (PEK), polyetherimide (PEI), thermoplastic polyimide, polyamideimide (PAI), polyether ketone ketone (PEKK), polyphenylene ether (PPE), polyether sulfone (PES), polysulfone (PSU), polyarylate (PAR), polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene Phthalate, polycarbonate (PC), polyoxymethylene (POM), polypropylene (PP), polyethylene (PE), polymethylpentene (TPX), polystyrene ( S), polymethyl methacrylate, acrylonitrile - styrene copolymer (AS), acrylonitrile - butadiene - styrene copolymer (ABS) and the like. These thermoplastic resins can be blended in a molten state by melt kneading. However, the thermoplastic resin may be made into a fiber or particle and dispersed in the polyamide resin composition of the present invention. An optimum amount of the thermoplastic resin may be selected, but a maximum of 50 parts by mass can be added to 100 parts by mass of the copolymerized polyamide resin (A). Of course, the thermoplastic resin contained in the polyamide resin composition of the present invention may be only the copolymerized polyamide (A).

  As the impact modifier, ethylene-propylene rubber (EPM), ethylene-propylene-diene rubber (EPDM), ethylene-acrylic acid copolymer, ethylene-acrylic acid ester copolymer, ethylene-methacrylic acid copolymer, ethylene- Polyolefin resins such as methacrylic acid ester copolymer, ethylene vinyl acetate copolymer, styrene-butadiene-styrene block copolymer (SBS), styrene-ethylene-butylene-styrene block copolymer (SEBS), styrene-isoprene -Polytetramethylene glycol, polycaprolactone, or poly (polyethylene glycol) as a hard segment made of vinyl polymer resin such as styrene copolymer (SIS), acrylate copolymer, polybutylene terephthalate or polybutylene naphthalate. Polyester block copolymer in which the ball sulfonate diol as a soft segment, a nylon elastomer, urethane elastomer, acrylic elastomer, silicone rubber, fluorinated rubber, and the like polymer particles having a core-shell structure constituted from two different polymers. An optimum amount of the impact modifier may be selected, but a maximum of 30 parts by mass can be added to 100 parts by mass of the copolymerized polyamide resin (A).

  When a thermoplastic resin other than the copolymerized polyamide resin (A) and an impact resistance improving material are added to the polyamide resin composition of the present invention, a reactive group capable of reacting with the polyamide is copolymerized. Preferably, the reactive group is a group capable of reacting with an amino group, a carboxyl group and a main chain amide group which are terminal groups of the polyamide resin. Specific examples include a carboxylic acid group, an acid anhydride group, an epoxy group, an oxazoline group, an amino group, an isocyanate group, etc. Among them, an acid anhydride group is most excellent in reactivity. There is also a report that the thermoplastic resin having a reactive group that reacts with the polyamide resin is finely dispersed in the polyamide and is finely dispersed, so that the distance between the particles is shortened and the impact resistance is greatly improved [ S, Wu: Polymer 26, 1855 (1985)].

  As a flame retardant, a combination of a halogen flame retardant and a flame retardant aid is good. As a halogen flame retardant, brominated polystyrene, brominated polyphenylene ether, brominated bisphenol type epoxy polymer, brominated styrene maleic anhydride Polymers, brominated epoxy resins, brominated phenoxy resins, decabromodiphenyl ether, decabromobiphenyl, brominated polycarbonate, perchlorocyclopentadecane, brominated cross-linked aromatic polymers, etc. are preferred. Examples include layered silicates such as antimony, antimony pentoxide, sodium antimonate, zinc stannate, zinc borate, and montmorillonite, fluorine-based polymers, and silicones. Among these, from the viewpoint of thermal stability, the halogen flame retardant is preferably a combination of dibromopolystyrene, and the flame retardant aid is a combination of antimony trioxide, sodium antimonate, or zinc stannate. Non-halogen flame retardants include melamine cyanurate, red phosphorus, phosphinic acid metal salts, and nitrogen-containing phosphoric acid compounds. In particular, a combination of a phosphinic acid metal salt and a nitrogen-containing phosphoric acid compound is preferable, and examples of the nitrogen-containing phosphoric acid compound include melamine or a melamine condensate such as melam and melon and polyphosphoric acid reactive organisms or those. A mixture of As other flame retardants and flame retardant aids, addition of hydrotalcite-based compounds and alkali compounds is preferable as metal corrosion prevention for molds and the like when these flame retardants are used. The addition amount of the flame retardant may be an optimum amount, but it is possible to add a maximum of 50 parts by mass with respect to 100 parts by mass of the copolymerized polyamide resin (A).

  Examples of the release agent include long chain fatty acids or esters thereof, metal salts, amide compounds, polyethylene wax, silicone, polyethylene oxide, and the like. The long chain fatty acid preferably has 12 or more carbon atoms, and examples thereof include stearic acid, 12-hydroxystearic acid, behenic acid, and montanic acid. Partial or total carboxylic acid is esterified with monoglycol or polyglycol. Or a metal salt may be formed. Examples of the amide compound include ethylene bisterephthalamide and methylene bisstearyl amide. These release agents may be used alone or as a mixture. The addition amount of the release material may be selected as an optimum amount, but it is possible to add up to 5 parts by mass with respect to 100 parts by mass of the copolymerized polyamide resin (A).

  The polyamide resin composition preferably has a melting point (Tm) of 300 to 330 ° C. and a temperature rising crystallization temperature (Tc1) of 90 to 120 ° C. When the melting point exceeds the above upper limit, the processing temperature required for injection molding of the polyamide resin composition of the present invention becomes extremely high, so that it may be decomposed during processing and the desired physical properties and appearance may not be obtained. On the other hand, when Tm is less than the lower limit, the crystallization rate is slow, and in any case, molding may be difficult. The temperature rise crystallization temperature Tc1 is a temperature at which crystallization starts when the temperature is raised from room temperature. If the ambient temperature of the resin composition at the time of molding is lower than Tc1, crystallization hardly proceeds. On the other hand, when the temperature of the resin composition becomes higher than Tc1, crystallization proceeds easily, and dimensional stability, physical properties, etc. can be sufficiently exhibited. Therefore, if the Tc1 of the resin composition is high, it is necessary to increase the mold temperature accordingly, leading to a decrease in workability. When Tc1 exceeds the upper limit, not only the mold temperature required for injection molding of the polyamide resin composition of the present invention becomes high and molding becomes difficult, but also in a short cycle of injection molding. Crystallization may not progress, causing molding difficulties such as insufficient mold release, or because crystallization is not sufficiently completed, deformation and crystal shrinkage occur during heating in the subsequent process, and sealants and lead frames The problem of peeling off occurs and the reliability is lacking. Conversely, when Tc1 is less than the above lower limit, it is necessary to inevitably lower the glass transition temperature as a resin composition. Since Tc1 is generally a temperature higher than the glass transition temperature, when Tc1 is less than 90 ° C., a lower value is required as the glass transition temperature. In that case, the physical properties greatly decrease or the physical properties after water absorption. Problems that cannot be maintained. Since it is necessary to keep Tg relatively high, Tc1 is preferably at least 90 ° C. or higher.

  In the copolymerized polyamide resin (A), since a specific amount of the polyamide 11 component is copolymerized with the polyamide 6T, a resin having an excellent balance of low water absorption and fluidity in addition to a high melting point and moldability can be obtained. In the molding of engine cooling water system parts, in addition to a high melting point of 300 ° C. or higher and low water absorption, thin-walled, high-cycle molding is required. In the hexamethylene terephthalamide / polyhexamethylene adipamide copolymer (polyamide 6T / 66), although the moldability is good, the water absorption is extremely high. Therefore, deterioration of physical properties due to water absorption tends to be a problem. On the other hand, polynonamethylene terephthalamide (polyamide 9T) has low water absorption, but since Tg is 125 ° C., Tc1 is inevitably 125 ° C. or higher, and the mold temperature during molding is 140 ° C. or higher. Therefore, there is a difficulty in moldability. Even if molding is attempted with a low-temperature mold, problems such as insufficient fluidity and secondary shrinkage or deformation due to crystallization during use in subsequent processes or use. From the background as described above, a resin having a high melting point of 300 ° C. or higher, low water absorption, easy moldability, and high fluidity is required. In the copolymerized polyamide resin (A), a specific amount of polyamide is added to polyamide 6T. By copolymerizing 11, in addition to imparting a high melting point, low water absorption and fluidity, Tc1 can be kept low, and the processability of injection molding can be greatly improved.

  The polyamide resin composition of this invention can be manufactured by mix | blending each above-mentioned component with a conventionally well-known method. For example, each component is added during the polycondensation reaction of the copolymerized polyamide resin (A), the blended polyamide resin (A) and other components are dry blended, or a twin screw type extruder is used. The method of melt-kneading each structural component can be mentioned.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. In addition, the measured value described in the Example is measured by the following method.

(1) Relative viscosity 0.25 g of polyamide resin was dissolved in 25 ml of 96% sulfuric acid and measured at 20 ° C. using an Ostwald viscometer.

(2) Terminal carboxyl group concentration 20 mg of polyamide resin was dissolved in HFIP + CDCl ₃ (1 + 1), 8 mg of formic acid was added, and H-NMR measurement was performed. Expressed in equivalent (equivalent / ton) in 1 ton of resin.

(3) Melting point (Tm) and temperature rising crystallization temperature (Tc1)
Using an injection molding machine EC-100 manufactured by Toshiba Machine, the cylinder temperature is set to the melting point of the resin + 20 ° C., the mold temperature is set to 35 ° C., the length 127 mm, the width 12.6 mm, and the thickness 0.8 mmt. A piece was injection molded to produce a test piece. In order to measure the melting point (Tm) and temperature rising crystallization temperature (Tc1) of the obtained test piece, 5 mg of a part of the test piece is weighed in an aluminum pan, sealed with an aluminum lid, and a measurement sample. Then, using a differential scanning calorimeter (SSC / 5200 manufactured by SEIKO INSTRUMENTS), the temperature was raised from room temperature to 20 ° C./min in a nitrogen atmosphere, and the measurement was carried out to 350 ° C. At that time, the peak top temperature of the highest temperature peak among the exothermic peaks obtained was defined as the temperature raising crystallization temperature (Tc1). The temperature was further raised, and the peak top temperature of endotherm due to melting was defined as the melting point (Tm).

(4) Formability and dimensional change amount Using Toshiba Machine's injection molding machine EC-100, the cylinder temperature was set to the melting point of the resin + 20 ° C., the mold temperature was set to 120 ° C. Injection molding was performed using a flat plate forming mold having a thickness of 1 mm. Molding was performed at an injection speed of 50 mm / sec, a holding pressure of 30 MPa, an injection time of 10 seconds, and a cooling time of 10 seconds. The quality of the moldability was evaluated as follows.
○: A molded product can be obtained without problems.
Δ: Sprue sometimes remains in the mold.
X: The releasability is insufficient, and the molded product sticks to the mold or deforms.
Furthermore, in order to evaluate the dimensional stability of the obtained molded product, the molded product was heated at 180 ° C. for 1 hour. The dimension in the direction perpendicular to the flow direction before and after heating was measured, and the amount of dimensional change was determined as follows.
Dimensional change (%) = (Dimension before heating (mm) −Dimension after heating (mm)) / Dimension before heating (mm) × 100
Dimensional stability was evaluated as follows.
○: Dimensional change is less than 0.2% ×: Dimensional change is 0.2% or more

(5) Saturated water absorption (80 ° C hot water)
Using Toshiba Machine's injection molding machine EC-100, the cylinder temperature is set to the melting point of the resin + 20 ° C., the mold temperature is set to 140 ° C., and a flat plate having a length of 100 mm, a width of 100 mm, and a thickness of 1 mm is injection-molded. Was made. This test piece was immersed in hot water of 80 ° C. for 50 hours, and the saturated water absorption (%) was determined from the following formula from the mass at the time of saturated water absorption and drying.
Saturated water absorption (%) = {(mass at the time of saturated water absorption−mass at the time of drying) / mass at the time of drying} × 100

(6) Tensile strength Measured according to ISO527-2 standard.
(7) Boiling water 2000 hour strength reduction rate Tensile strength was measured for ISO tensile test pieces (A-type dumbbells) immersed in boiling water for 2000 hours, and the following strength reduction rate (%) was obtained.
Strength reduction rate (%) = {(initial tensile strength−tensile strength after immersion for 2000 hours) / initial tensile strength} × 100

(8) Calcium chloride resistance An ISO tensile test piece (A type dumbbell) was left to stand in an environment of 80 ° C. and 95% RH for 4 hours, “5% calcium chloride solution was applied to the surface of the molded piece”, “100 ° C. The treatment of “2 hours in oven” and “left at room temperature for 18 hours” was defined as 1 cycle, and the tensile strength after 10 cycles was measured to obtain the strength retention (%).
Strength reduction rate (%) = {(initial tensile strength−tensile strength after 10 cycles) / initial tensile strength} × 100

<Synthesis Example 1>
1.96 kg of 1,6-hexamethylenediamine, 9.96 kg of terephthalic acid, 8.04 kg of 11-aminoundecanoic acid, 9 g of sodium diphosphite, 40 g of acetic acid as a terminal conditioner and 17.52 kg of ion-exchanged water The mixture was charged into a liter autoclave, pressurized with N ₂ from normal pressure to 0.05 MPa, released, and returned to normal pressure. This operation was performed 3 times, N ₂ substitution was performed, and then uniform dissolution was performed at 135 ° C. and 0.3 MPa with stirring. Thereafter, the solution was continuously supplied by a liquid feed pump, heated to 240 ° C. with a heating pipe, and heated for 1 hour. Thereafter, the reaction mixture was supplied to a pressure reaction can, heated to 290 ° C., and a part of water was distilled off so as to maintain the internal pressure of the can at 3 MPa to obtain a low-order condensate. Then, this low-order condensate is directly supplied to a twin-screw extruder (screw diameter 37 mm, L / D = 60) while maintaining the molten state, and the resin temperature is 320 ° C. while draining water from three vents. The polycondensation proceeded under melting to obtain a copolymerized polyamide resin (A1). The obtained copolymerized polyamide resin (A1) had a melting point of 302 ° C., a relative viscosity of 2.1, and a terminal carboxyl group amount of 94 equivalents / ton. Table 1 shows the charging ratio of the raw material monomers of the copolymerized polyamide resin (A1) of Synthesis Example 1.

<Synthesis Example 2>
The amount of 1,6-hexamethylenediamine was changed to 7.54 kg, the amount of terephthalic acid was changed to 10.79 kg, the amount of 11-aminoundecanoic acid was changed to 7.04 kg, and the resin of the twin screw extruder The temperature was changed to 335 ° C. A copolymerized polyamide resin (A2) was synthesized in the same manner as in Synthesis Example 1 except for these. The obtained copolymerized polyamide resin (A2) had a melting point of 314 ° C., a relative viscosity of 2.1, and a terminal carboxyl group content of 89 equivalents / ton. Table 1 shows the charging ratio of the raw material monomers of the copolymerized polyamide resin (A2) of Synthesis Example 2.

<Synthesis Example 3>
The amount of 1,6-hexamethylenediamine was changed to 8.12 kg, the amount of terephthalic acid was changed to 11.62, the amount of 11-aminoundecanoic acid was changed to 6.03 kg, and the resin of the twin screw extruder The temperature was changed to 345 ° C. A copolymerized polyamide resin (A3) was synthesized in the same manner as in Synthesis Example 1 except for these. The obtained copolymerized polyamide resin (A3) had a melting point of 328 ° C., a relative viscosity of 2.1, and a terminal carboxyl group amount of 103 equivalents / ton. Table 1 shows the charging ratio of the raw material monomers of the copolymerized polyamide resin (A3) of Synthesis Example 3.

<Synthesis Example 4>
The amount of 1,6-hexamethylenediamine was changed to 8.12 kg, the amount of terephthalic acid was changed to 9.96 kg, the amount of 11-aminoundecanoic acid was changed to 6.03 kg, and adipic acid (other than terephthalic acid) The dicarboxylic acid (1.46 kg) was charged, and the resin temperature of the twin screw extruder was changed to 330 ° C. A copolymerized polyamide resin (A4) was synthesized in the same manner as in Synthesis Example 1 except for these. The obtained copolymerized polyamide resin (A4) had a melting point of 310 ° C., a relative viscosity of 2.1, and a terminal carboxyl group content of 88 equivalents / ton. Table 1 shows the charging ratio of raw material monomers of the copolymerized polyamide resin (A4) of Synthesis Example 4.

<Synthesis Example 5>
7.04 kg of 11-aminoundecanoic acid was changed to 6.41 kg of undecane lactam, and the resin temperature of the twin screw extruder was changed to 335 ° C. A copolymerized polyamide resin (A5) was synthesized in the same manner as in Synthesis Example 1 except for these. The obtained copolymerized polyamide resin (A5) had a melting point of 315 ° C., a relative viscosity of 2.1, and a terminal carboxyl group content of 95 equivalents / ton. Table 1 shows the charging ratio of the raw material monomers of the copolymerized polyamide resin (A5) of Synthesis Example 5.
<Synthesis Example 6>
According to the method described in Synthesis Example 1, a copolymerized polyamide resin (A6) having a terminal carboxyl group amount of 15 equivalents / ton, a melting point of 302 ° C., and a relative viscosity of 2.0 was obtained. Table 1 shows the charging ratio of the raw material monomers.

<Comparative Synthesis Example 1>
According to the method described in Example 1 of WO06 / 112300, from a terephthalic acid unit, an adipic acid unit, and a 1,6-hexamethylenediamine unit (molar ratio of terephthalic acid unit: adipic acid unit is 63:37) Copolyamide (A7) was synthesized. The obtained copolymer polyamide (A7) had a relative viscosity of 2.1 and a terminal carboxyl group content of 44 equivalents / ton. Table 1 shows the charging ratio of raw material monomers of the copolymerized polyamide resin of Comparative Synthesis Example 1.

<Comparative Synthesis Example 2>
According to the method described in Example 1 of JP-A-7-228689, a terephthalic acid unit, a 1,9-nonanediamine unit and a 2-methyl-1,8-octanediamine unit (1,9-nonanediamine unit: 2 -Methyl-1,8-octanediamine unit molar ratio 85:15), melting point 306 ° C., relative viscosity 2.1, terminal carboxyl group amount 15 equivalents / ton (however, the end-capping agent uses benzoic acid) The copolymerized polyamide resin (A8) was synthesized. Table 1 shows the charging ratio of raw material monomers for the copolymerized polyamide resin (A8) of Comparative Synthesis Example 2.

<Comparative polyamide>
Polyamide 66 (PA66):
Toyobo Nylon T-662 Relative viscosity 2.8 Terminal carboxyl group content 40 equivalents / ton

Hereinafter, Example 6 is read as Reference Example 6.
Examples 1-6, Comparative Examples 1-3
The components and weight ratios shown in Table 2 were melt-kneaded at a melting point of each copolymer polyamide + 30 ° C. using a twin screw extruder STS-35 manufactured by Coperion Co., Ltd., Examples 1 to 6 and Comparative Examples 1 to 3 A polyamide resin composition was obtained.
Glass fiber (manufactured by Nitto Boseki Co., Ltd., CS-3J-324) was used as the fibrous reinforcing agent (B). In addition, 0.5 parts by mass of magnesium stearate as a releasing agent and pentaerythrityl tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) as a stabilizer per 100 parts by mass of polyamide resin Propionate] (manufactured by Ciba Specialty Chemicals, Irganox 1010) was blended in an amount of 0.3 part by mass.

  The polyamide resin compositions obtained in Examples 1 to 6 and Comparative Examples 1 to 3 were used for evaluation of various properties. The results are shown in Table 2.

  As is clear from Table 2, in Examples 1 to 6, not only the moldability and dimensional stability at a low temperature mold temperature and low water absorption are satisfied, but also the conventional product can be obtained even in boiling water 2000 hours. It can be understood that it is not suitable for engine cooling water system parts. On the other hand, in Comparative Example 1, although the moldability is good, the water absorption is high, and the strength reduction after 2,000 hours of boiling water is large. Moreover, in Comparative Example 2, although it is excellent in low water absorption, the moldability is inferior and the strength reduction rate after 2000 hours of boiling water is also inferior. The polyamide 66 shown for reference has extremely high water absorption, and the strength is significantly reduced after 2000 hours of boiling water.

  The polyamide resin composition of the present invention is suitable for engine cooling water system parts, such as radiator tank parts, coolant reserve tanks, water pipes, water inlet pipes, water outlet pipes, water pump housings, water pump impellers, water valves, etc. It can be used for water pump parts.

Claims (5)

The fibrous reinforcing agent (B) is added to 100 parts by mass of the copolymerized polyamide resin (A) composed of 55 to 75 mol% of (a) hexamethylene terephthalamide units and 45 to 25 mol% of (b) undecanamide units. It is a composition containing 20 to 150 parts by mass, and the composition satisfies the following (a) and (b), and the terminal carboxyl group concentration of the copolymerized polyamide resin (A) is 80 to 120 equivalents / ton. A polyamide resin composition for engine cooling water system parts, characterized in that it exists .
(A) Saturated water absorption (%) in hot water at 80 ° C. is 3.0% or less (b) Tensile strength reduction rate (%) after immersion in boiling water for 2000 hours is 30% or less   The copolymerized polyamide resin (A) is (c) a structural unit obtained from an equivalent molar salt of a diamine other than the structural unit of (a) and a dicarboxylic acid, or an aminocarboxylic acid other than the structural unit of (b) or The polyamide resin composition for engine cooling water system parts according to claim 1, which contains up to 20 mol% of a structural unit obtained from lactam. The polyamide resin composition for engine cooling water system parts according to any one of claims 1 to 2 , wherein the polyamide resin composition has a melting point of 300 to 330 ° C and a temperature rising crystallization temperature (Tc1) of 90 to 120 ° C. Engine cooling water system parts obtained using the polyamide resin composition according to any one of claims 1 to 3 . The engine cooling water system according to claim 4 , wherein the engine cooling water system component is any of a radiator tank component, a coolant reserve tank, a water pipe, a water inlet pipe, a water outlet pipe, a water pump housing, a water pump impeller, and a water valve. parts.