JP2006176597A - Polyamide resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyamide resin composition improved in not only water resistance, oil resistance and metal halide resistance but also resistance to hydrolysis in especially high-temperature acidic media. <P>SOLUTION: The polyamide resin composition comprises 100 pts.mass of a polyamide resin (A) and 0.01-20 pts.mass of an aliphatic or alicyclic carbodiimide (B), wherein the polyamide resin A is composed of (a) dicarboxylic acid units including 50-100 mol% of terephthalic acid units and (b) diamine units including 60-100 mol% of 6-18C aliphatic alkylenediamine units and has an intrinsic viscosity of 0.6-2.0 dL/g determined at 30°C in concentrated sulfuric acid. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a polyamide resin composition having improved water resistance, oil resistance and metal halide resistance resistance, and in particular, a polyamide resin composition having improved resistance to decomposition due to contact with a high-temperature automobile fluid, And a molded article comprising this polyamide resin composition.

  Conventionally, it is known that polyamide resins are very stable in an alkaline medium, but in an acidic medium, the amide bond is cleaved very easily by undergoing a hydrolysis reaction or radical reaction by the action of an acid. ing. As a method for protecting the polyamide resin from hydrolysis, a method of adding aromatic carbodiimide to the polyamide resin has been proposed (see Patent Document 1). However, since aromatic carbodiimide is generally thermosetting, there is a problem of self-crosslinking when melt kneaded with a polyamide resin. For this reason, there is a problem in that a mass of a crosslinked product of aromatic carbodiimide is mixed inside the polyamide resin, and kneading between the polyamide resin and the aromatic carbodiimide becomes insufficient. In addition, in order to suppress the self-crosslinking of aromatic carbodiimide, there are also known those in which a substituent is introduced into the molecule, but when such aromatic carbodiimide and polyamide resin are melt-kneaded, heating is performed. On the other hand, although self-crosslinking can be hindered, the decomposition of aromatic carbodiimide is promoted to generate decomposition gas, resulting in contamination of the processing environment, and it has been pointed out that it cannot withstand actual use.

  On the other hand, metal members have been used for members that are mainly required to have water resistance, such as members used around the engine of automobiles. However, polyamide 6, polyamide 66, polyamide 46, and the like are excellent. A member made of an aliphatic polyamide resin having mechanical properties as a base material is also often used because it is lighter than a metal member. However, these members made of aliphatic polyamide resin as a base material may be fluid heated to high temperature (for example, coolant (hereinafter sometimes abbreviated as LLC) or automatic transmission fluid (hereinafter abbreviated as ATF). ], When used in brake fluid [hereinafter sometimes abbreviated as BF]), its oil resistance, hydrolysis resistance and other characteristics are not sufficient, and it deteriorates with time, resulting in a significant decrease in strength. There was a problem. Among such deteriorations, the deterioration in the case of using an aliphatic polyamide resin in LLC is considered to be due to hydrolysis of the aliphatic polyamide resin in the member due to the condition of high temperature and acidity.

  Therefore, as a method for improving the hydrolysis resistance, oil resistance and the like of these aliphatic polyamide resins, a method of adding aliphatic carbodiimide to the aliphatic polyamide resin has been proposed (see Patent Document 2). However, the improvement effect is not yet sufficient, and it is necessary to use a metal member particularly in a high temperature atmosphere where heat resistance is also required.

  Instead of the aforementioned aliphatic polyamide resin, polyethersulfone (PES), polyphenylene sulfide (PPS), polyphenylene sulfide (PPS), which have excellent mechanical properties, are lighter than metal members, and exhibit heat resistance to higher temperatures. The use of super engineering plastics such as ether ether ketone (PEEK) is also being studied, but many of these super engineering plastics are less flexible than aliphatic polyamide resins and are expensive, so that However, it is limited and has not yet been put into practical use.

JP-A-6-16933 Japanese Patent Laid-Open No. 11-343408

  The present invention has been made in view of the drawbacks of the prior art, and is a polyamide resin composition having improved resistance to hydrolysis in a high-temperature acidic medium as well as water resistance, oil resistance and metal halide resistance. The purpose is to provide goods.

  The present inventors have found that the above object can be achieved by blending a specific amount of an aliphatic or alicyclic carbodiimide with a polyamide resin having a specific structural unit and intrinsic viscosity, and completed the present invention. .

  That is, the present invention comprises a dicarboxylic acid unit (a) containing 50 to 100 mol% terephthalic acid units and a diamine unit (b) containing 60 to 100 mol% aliphatic alkylenediamine units having 6 to 18 carbon atoms. The aliphatic or alicyclic carbodiimide (B) 0 with respect to 100 parts by mass of the polyamide resin (A) having an intrinsic viscosity of 0.6 to 2.0 dl / g measured in concentrated sulfuric acid at 30 ° C. Provided is a polyamide resin composition containing 0.01 to 20 parts by mass, and a molded article formed therefrom.

  Since the polyamide resin composition of the present invention is mainly composed of a polyamide resin having a specific structural unit and intrinsic viscosity, it exhibits excellent water resistance, oil resistance and halogenated metal salt resistance. Since it contains a specific amount of alicyclic carbodiimide, it exhibits not only oil resistance but also resistance to hydrolysis in a high temperature acidic medium, and particularly excellent hydrolysis resistance in high temperature LLC.

  The polyamide resin composition of the present invention contains a specific polyamide resin (A) and an aliphatic or alicyclic carbodiimide (B) in a specific blending ratio, and the polyamide resin (A) is an essential component. It consists of a specific dicarboxylic acid unit (a) and a diamine unit (b) and exhibits an intrinsic viscosity in a specific range.

  The dicarboxylic acid unit (a) constituting the polyamide resin (A) used in the present invention has a terephthalic acid unit of 50 to 100 mol%, preferably 60 to 100 mol%, more preferably 75 to 75% from the viewpoint of improving heat resistance. It is contained in a range of 100 mol%, particularly preferably 90 to 100 mol%. This is because when the content of the terephthalic acid unit in the dicarboxylic acid unit (a) is less than 50 mol%, the heat resistance of the resulting polyamide resin composition is too low.

  The dicarboxylic acid unit (a) is 50 mol% or less, preferably 40 mol% or less, more preferably 25 mol% or less, and particularly preferably 10 mol% or less. It may contain an acid unit. Such other dicarboxylic acid units include malonic acid, dimethylmalonic acid, succinic acid, glutaric acid, adipic acid, 2-methyladipic acid, trimethyladipic acid, pimelic acid, 2,2-dimethylglutaric acid, 2,2- Aliphatic dicarboxylic acids such as diethyl succinic acid, azelaic acid, sebacic acid and suberic acid; alicyclic dicarboxylic acids such as 1,3-cyclopentanedicarboxylic acid and 1,4-cyclohexanedicarboxylic acid; isophthalic acid, 2,6- Naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,4-phenylenedioxydiacetic acid, 1,3-phenylenedioxydiacetic acid, diphenic acid, diphenylmethane-4,4'- Dicarboxylic acid, diphenylsulfone-4,4′-dicarboxylic acid, 4,4′-biphenyldicarbo Can be mentioned units derived from aromatic dicarboxylic acids such as acid, it can be used one or two or more of them. Of these, units derived from aromatic dicarboxylic acids are preferred. Furthermore, units derived from polyvalent carboxylic acids such as trimellitic acid, trimesic acid, and pyromellitic acid may be included within a range in which melt molding is possible.

  The diamine unit (b) constituting the polyamide resin (A) contains 60 to 100 mol%, preferably 75 to 100 mol%, more preferably 90 to 100 mol% of an aliphatic alkylenediamine having 6 to 18 carbon atoms. . This is because when the content of the aliphatic alkylenediamine unit having 6 to 18 carbon atoms in the diamine unit (b) is less than 60 mol%, the resulting polyamide resin composition has heat resistance, low water absorption, and chemical resistance. This is because various physical properties such as properties are too low. Further, since the melting point of the polyamide resin (A) is increased when the aliphatic alkylene diamine has less than 5 carbon atoms, the molding temperature is increased when a molded product is produced from the obtained polyamide resin composition by injection molding or the like. As a result, it tends to be difficult to achieve both suppression of the thermal decomposition reaction and moldability during molding of the polyamide resin composition, while the aliphatic alkylenediamine has more than 19 carbon atoms. This is because the polyamide resin composition tends to cause a decrease in heat resistance and mechanical properties.

  Specific examples of the C6-C18 aliphatic alkylenediamine unit include, for example, 1,6-hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,10- Linear aliphatic alkylenediamines such as decanediamine, 1,11-undecanediamine, 1,12-dodecanediamine; 1-butyl-1,2-ethanediamine, 1,1-dimethyl-1,4-butanediamine, 1-ethyl-1,4-butanediamine, 1,2-dimethyl-1,4-butanediamine, 1,3-dimethyl-1,4-butanediamine, 1,4-dimethyl-1,4-butanediamine, 2,3-dimethyl-1,4-butanediamine, 2-methyl-1,5-pentanediamine, 3-methyl-1,5-pentanediamine, 2,5-dimethyl- , 6-hexanediamine, 2,4-dimethyl-1,6-hexanediamine, 3,3-dimethyl-1,6-hexanediamine, 2,2-dimethyl-1,6-hexanediamine, 2,2,4 -Trimethyl-1,6-hexanediamine, 2,4,4-trimethyl-1,6-hexanediamine, 2,4-diethyl-1,6-hexanediamine, 2,2-dimethyl-1,7-heptanediamine 2,3-dimethyl-1,7-heptanediamine, 2,4-dimethyl-1,7-heptanediamine, 2,5-dimethyl-1,7-heptanediamine, 2-methyl-1,8-octanediamine 3-methyl-1,8-octanediamine, 4-methyl-1,8-octanediamine, 1,3-dimethyl-1,8-octanediamine, 1,4-dimethyl-1,8-octane Diamine, 2,4-dimethyl-1,8-octanediamine, 3,4-dimethyl-1,8-octanediamine, 4,5-dimethyl-1,8-octanediamine, 2,2-dimethyl-1,8 -From branched aliphatic alkylene diamines such as octanediamine, 3,3-dimethyl-1,8-octanediamine, 4,4-dimethyl-1,8-octanediamine, and 5-methyl-1,9-nonanediamine The unit induced | guided | derived can be mentioned and 1 type (s) or 2 or more types can be used among these.

  Among the above aliphatic alkylenediamine units having 6 to 18 carbon atoms, 1,6-hexanediamine, 1,8-octanediamine, 2-methyl-1,8-octanediamine, 1,9-nonanediamine, 1,10 Units derived from -decanediamine, 1,11-undecanediamine, and 1,12-dodecanediamine are preferred, and 1,9-nonanediamine units and / or 2-methyl-1,8-octanediamine units are more preferred.

  When a 1,9-nonanediamine unit and / or 2-methyl-1,8-octanediamine unit is used as the aliphatic alkylenediamine unit having 6 to 18 carbon atoms, 1,9-nonanediamine in the diamine unit (b) The total content of the unit and the 2-methyl-1,8-octanediamine unit is preferably 60 to 100 mol%, and more preferably 90 to 100 mol%. When the polyamide resin (A) containing 1,9-nonanediamine unit and 2-methyl-1,8-octanediamine unit in the above proportion is used, toughness, slidability, heat resistance, moldability, low water absorption, A polyamide resin composition having further excellent lightness can be obtained.

  Further, when a 1,9-nonanediamine unit and / or 2-methyl-1,8-octanediamine unit is used as the aliphatic alkylenediamine unit having 6 to 18 carbon atoms, 1,1 included in the diamine unit (b). The molar ratio of the 9-nonanediamine unit to the 2-methyl-1,8-octanediamine unit is preferably the former / the latter = 95/5 to 50/50, and the former / the latter = 90/10 to 60/40. More preferably. This is because when the content of 1,9-nonanediamine unit is larger than the above ratio, the melting point becomes high. Therefore, when a molded product is produced by injection molding or the like, it is necessary to set the molding temperature high and suppress the thermal decomposition reaction. This is because it tends to be difficult to achieve both moldability and moldability. Further, in the mechanical properties, the tensile elongation property and impact resistance of the polyamide resin tend to be lowered. On the contrary, if the molar ratio of 1,9-nonanediamine units is less than the above ratio, the crystallinity is lowered, so that the heat resistance, mechanical properties and the like tend to be lowered.

  If the diamine unit (b) is 40 mol% or less, preferably 25 mol% or less, more preferably 10 mol%, it contains other diamine units other than C6-C18 aliphatic alkylenediamine units. May be. Such other diamine units include aliphatic diamines such as ethylenediamine, propylenediamine, and 1,4-butanediamine; alicyclic diamines such as cyclohexanediamine, methylcyclohexanediamine, and isophoronediamine; p-phenylenediamine, m-phenylenediamine. , Units derived from aromatic diamines such as xylylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylsulfone, and 4,4′-diaminodiphenylether. Among them, one kind or two or more kinds can be used. The content of these other diamine units in the diamine unit (b) is more preferably as follows.

  The polyamide resin (A) is preferably 10% or more, more preferably 40% or more, and still more preferably 40% or more of the end group of the molecular chain in order to impart good melt stability and hot water resistance to the polyamide resin composition. 60% or more is sealed with a terminal sealing agent.

The end-capping rate of the polyamide resin (A) was determined by measuring the number of carboxyl group ends, the number of amino group ends, and the number of end groups blocked by the end-capping agent present in the polyamide, respectively. It can be determined according to equation (1). Here, the number of each terminal group is preferably determined from the integral value of the characteristic signal corresponding to each terminal group by ¹ H-NMR in terms of accuracy and simplicity.

  In the formula (1), A represents the total number of end groups of the molecular chain (this is usually equal to twice the number of polyamide molecules), and B represents the remaining carboxyl group end and amino group end of the unblocked group. Represents the total number.

  As the end-capping agent, various monofunctional compounds having reactivity with the amino group or carboxyl group at the end of the polyamide can be used. From the viewpoint of reactivity and stability of the capped end, monocarboxylic acid Alternatively, monoamine can be preferably used. Among these, monocarboxylic acids can be used more preferably from the viewpoint of easy handling. In addition, acid anhydrides, monoisocyanates, monohalides, monoesters, monoalcohols, and the like can also be used as the end-capping agent.

  As the monocarboxylic acid that can be used as an end-capping agent, those having reactivity with an amino group can be used. For example, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, lauric acid, Aliphatic monocarboxylic acids such as tridecanoic acid, myristic acid, palmitic acid, stearic acid, pivalic acid and isobutyric acid; alicyclic monocarboxylic acids such as cyclohexanecarboxylic acid; benzoic acid, toluic acid, α-naphthalenecarboxylic acid, β -Aromatic monocarboxylic acids such as naphthalene carboxylic acid, methyl naphthalene carboxylic acid, and phenyl acetic acid; any mixtures of these can be used. Among these, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, lauric acid, tridecanoic acid, myristic acid, palmitic acid, stearin, etc. Acids and benzoic acid can be preferably used.

  As the monoamine that can be used as an end-capping agent, those having reactivity with a carboxyl group can be used, for example, methylamine, ethylamine, propylamine, butylamine, hexylamine, octylamine, decylamine, stearylamine, Preferred are aliphatic monoamines such as dimethylamine, diethylamine, dipropylamine, and dibutylamine; alicyclic monoamines such as cyclohexylamine and dicyclohexylamine; aromatic monoamines such as aniline, toluidine, diphenylamine, and naphthylamine; and any mixture thereof. Can be used. Of these, butylamine, hexylamine, octylamine, decylamine, stearylamine, cyclohexylamine, and aniline can be preferably used from the viewpoints of reactivity, boiling point, stability of the sealing end, price, and the like.

  The polyamide resin (A) used in the present invention can be produced using any method known as a method for producing crystalline polyamide. For example, it can be produced by a solution polymerization method or an interfacial polymerization method using acid chloride and diamine as raw materials, a melt polymerization method using dicarboxylic acid and diamine as raw materials, a solid phase polymerization method, a melt extrusion polymerization method, or the like.

  In producing the polyamide resin (A), in addition to the above-described end-capping agent, for example, as a catalyst, phosphoric acid, phosphorous acid, hypophosphorous acid, their salts or esters are added to the polymerization system. Can do. Examples of the salt or ester include phosphoric acid, phosphorous acid or hypophosphorous acid and metals such as potassium, sodium, magnesium, vanadium, calcium, zinc, cobalt, manganese, tin, tungsten, germanium, titanium, and antimony. Salt; ammonium salt of phosphoric acid, phosphorous acid or hypophosphorous acid; ethyl ester, isopropyl ester, butyl ester, hexyl ester, isodecyl ester, octadecyl ester, decyl ester of phosphoric acid, phosphorous acid or hypophosphorous acid , Stearyl ester, phenyl ester and the like.

  Moreover, as the polyamide resin (A) used in the present invention, if the intrinsic viscosity [η] measured under the condition of 30 ° C. in concentrated sulfuric acid is too low, the mechanical properties of the resulting polyamide resin composition are low. If the intrinsic viscosity is too low and the intrinsic viscosity is too high, the fluidity of the resulting polyamide resin composition is excessively lowered and the moldability tends to be lowered, so that the intrinsic viscosity [η] is 0.6-2. Use is 0 dl / g, preferably within the range of 0.7 to 1.9 dl / g.

  Examples of the aliphatic or alicyclic carbodiimide (B) contained as an essential component in the polyamide resin composition of the present invention include monocarbodiimide having one carbodiimide group in the molecule, and two or more carbodiimide groups in the molecule. The polycarbodiimide etc. which have can be used, and what was synthesize | combined by the generally well-known method can be used. For example, in the presence of a carbodiimidization catalyst, a diisocyanate compound corresponding to an aliphatic or alicyclic carbodiimide is subjected to a decarboxylation condensation reaction at a temperature of about 70 ° C. or higher in an inert solvent or without using a solvent. The synthesized one can be used.

  Among the aliphatic or alicyclic carbodiimides (B), specific examples of monocarbodiimide include dicyclohexylcarbodiimide, diisopropylcarbodiimide, dimethylcarbodiimide, diisobutylcarbodiimide, dioctylcarbodiimide, t-butylisopropylcarbodiimide, di-t-butylcarbodiimide and the like. Of these, dicyclohexylcarbodiimide and diisopropylcarbodiimide are preferable from the viewpoint of industrial availability.

  In addition, among aliphatic or alicyclic carbodiimides (B), as specific examples of polycarbodiimides, those produced by various methods can be used. Basically, conventional methods for producing polycarbodiimides ( US Pat. No. 2,941,956, Japanese Examined Patent Publication No. 47-33279, J. Org. Chem. 28, 2069-2075 (1963), Chemal Review 1981, Vo1.81 No. 4 p619-621) Can be used.

  In addition, as a diisocyanate that can be used as a synthesis raw material when producing a polycarbodiimide, for example, an aliphatic diisocyanate, an alicyclic diisocyanate, or a mixture thereof can be used. Specifically, hexamethylene diisocyanate, Examples include cyclohexane-1,4-diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4′-diisocyanate, and methylcyclohexane diisocyanate.

  In the method of producing polycarbodiimide, the degree of polymerization of polycarbodiimide is appropriately controlled by using a compound that reacts with the terminal isocyanate of carbodiimide and seals, for example, monoisocyanate, in the decarboxylation condensation reaction. can do. Specific examples of the monoisocyanate used for such purposes include phenyl isocyanate, tolyl isocyanate, dimethylphenyl isocyanate, cyclohexyl isocyanate, butyl isocyanate, and naphthyl isocyanate.

  The end-capping agent for sealing the end of the polycarbodiimide and controlling the degree of polymerization is not limited to the above-mentioned monoisocyanate, but is an active hydrogen having an active hydrogen that can react with an isocyanate group. Compounds can be used. As such an active hydrogen compound, a wide range of aliphatic, aromatic and alicyclic compounds having active hydrogen can be used. Specifically, methanol, ethanol, phenol, cyclohexanol, N-methylethanolamine, Compounds having a hydroxyl group such as polyethylene glycol monomethyl ether and polypropylene glycol monomethyl ether; secondary amines such as diethylamine and dicyclohexylamine; primary amines such as butylamine and cyclohexylamine; carboxylic acids such as succinic acid, benzoic acid and cyclohexanecarboxylic acid; Examples include thiols such as ethyl mercaptan, allyl mercaptan, thiophenol, and compounds having an epoxy group.

  Examples of the carbodiimidization catalyst used when producing an aliphatic or alicyclic carbodiimide by a decarboxylation condensation reaction of a diisocyanate compound include, for example, 1-phenyl-2-phospholene-1-oxide, 3-methyl-1-phenyl- Phosphorene oxide catalysts such as 2-phospholene-1-oxide, 1-ethyl-2-phospholene-1-oxide, 3-methyl-2-phospholene-1-oxide and their 3-phospholene isomers, tetrabutyl titanate, etc. Among these, 3-methyl-1-phenyl-2-phospholene-1-oxide can be preferably used from the viewpoint of reactivity.

  The blending amount of the aliphatic or alicyclic carbodiimide (B) is 0.01 to 20 parts by mass, preferably 0.01 to 18 parts by mass, more preferably 0.1 to 10 parts by mass with respect to 100 parts by mass of the polyamide resin. It is the range of mass parts. When the blending amount is less than 0.01 parts by mass, the sufficient effect of the present invention cannot be obtained, and when it exceeds 20 parts by mass, the content ratio of the polyamide resin (A) is relatively reduced. ) Is not preferable because it is difficult to reflect the physical properties derived from () in the polyamide resin composition.

  In order to improve the impact resistance and durability of the polyamide resin composition of the present invention, a modified polyolefin (C) may be further blended. As the modified polyolefin (C), a polyolefin modified by copolymerization with an α, β-unsaturated carboxylic acid, an ester thereof or a metal salt derivative thereof, or a carboxylic acid or an acid anhydride is grafted onto the polyolefin. Modified products can be used. Specific examples of these modified polyolefins include ethylene / propylene copolymers, ethylene / 1-butene copolymers, ethylene / 4-methyl-1-pentene copolymers, ethylene / 1-hexene copolymers. , Ethylene / 1-octene copolymer, ethylene / 1-decene copolymer, propylene / ethylene copolymer, propylene / 1-butene copolymer, propylene / 4-methyl-1-pentene copolymer, propylene / 4-methyl-1-pentene copolymer, propylene / 1-hexene copolymer, propylene / 1-octene copolymer, propylene / 1-decene copolymer, propylene / 1-dodecene copolymer, ethylene Propylene / 1,4-hexadiene copolymer, ethylene / propylene / dicyclopentadiene copolymer, ethylene / 1-butene / 1,4 Hexadiene copolymer, and ethylene-1-butene-5-ethylidene-2-norbornene copolymer and the like.

  If the blending amount of the modified polyolefin (C) in the polyamide resin composition of the present invention is too small relative to 100 parts by mass of the polyamide resin (A), the addition effect cannot be obtained, and if too large, the polyamide resin (A) Since the original physical properties may be impaired, it is preferably 1 to 100 parts by mass, more preferably 1 to 50 parts by mass.

  In the polyamide resin composition of the present invention, if necessary, fibrous fillers such as glass fiber, carbon fiber, boron fiber, aramid fiber, liquid crystal polyester fiber; potassium titanate whisker, aluminum borate whisker, calcium silicate whisker , Magnesium sulfate whisker, Calcium carbonate whisker, Zinc oxide whisker, Wollastonite, Sepiolite, Graphite whisker, etc. Needle fillers: Silica, silica alumina, alumina, talc, graphite, titanium dioxide, molybdenum disulfide, polytetrafluoroethylene You may mix | blend 1 type or multiple types of fillers, such as powdery fillers. When these fillers are blended at a ratio of preferably 1 to 100 parts by mass with respect to 100 parts by mass of the polyamide resin (A), a polyamide resin composition having a better balance between mechanical properties and moldability can be obtained. .

  In addition to the fillers described above, the polyamide resin composition of the present invention, if necessary, conventionally known copper-based stabilizers, hindered phenol-based antioxidants, hindered amine-based antioxidants, phosphorus-based compounds Antioxidants, thio antioxidants, colorants, ultraviolet absorbers, light stabilizers, antistatic agents, plasticizers, lubricants, crystal nucleating agents, flame retardants, or other types of polymers can be blended.

  The polyamide resin composition of the present invention can be produced according to a conventional method. For example, it can be produced by melt-kneading a polyamide resin (A), an aliphatic or alicyclic carbodiimide (B), and, if necessary, a modified polyolefin (C) or a filler, with an extruder. Here, the melt-kneading can be performed using a kneader such as a single-screw extruder, a twin-screw extruder, a kneader, a Banbury mixer, etc., and the type of apparatus used and the melt-kneading conditions are particularly limited. However, the polyamide resin composition of the present invention can be produced by, for example, kneading at a temperature in the range of about 300 to 350 ° C. for 1 to 30 minutes.

  The polyamide resin composition of the present invention described above is generally semi-finished, such as injection molding, extrusion molding, press molding, blow molding, calendar molding, casting molding, etc., depending on the type, application, shape, etc. of the target molded product. Various molded articles can be provided by molding by a molding method applied to the aromatic polyamide resin. In this case, you may shape | mold combining various shaping | molding methods. Furthermore, the polyamide resin composition of the present invention can be composite-molded with other polymers. Thus, from the polyamide resin composition of the present invention, automobile parts, industrial materials, industrial materials, electrical and electronic parts, machine parts, office equipment parts, household goods, containers, sheets, films, fibers, other arbitrary uses and Various shaped articles can be produced.

  In particular, the member formed of the molded article of the polyamide resin composition of the present invention is excellent in oil resistance, water resistance, metal halide resistance, and excellent in hydrolysis resistance in an acidic medium at high temperature. It is useful as a part to be used in a portion that comes into contact with an automobile fluid. Specific examples of such automotive fluids include brake fluid, automatic transmission fluid, power steering fluid, clutch fluid, shock absorber fluid, traction fluid, differential oil, engine oil, steering gear oil, gasoline, light oil, coolant fluid, and washer. Liquid, electrolytic solution, and the like.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In the following examples and comparative examples, the preparation of test pieces and the evaluation of LLC resistance were performed as described below.

<Preparation of test piece>
Using an 80-ton injection molding machine manufactured by Nissei Plastic Industry Co., Ltd., a JIS No. 1 dumbbell-shaped test piece (length 170 mm × thickness 3 mm) for LLC resistance evaluation under conditions of a cylinder temperature of 300 ° C. and a mold temperature of 140 ° C. X width 10 mm).

<LLC resistance test>
The test piece prepared as described above is immersed in a 50% ethylene glycol aqueous solution heated to 120 ° C. for a predetermined time (500, 1000, 1500, 2000 hours), and then an autograph (manufactured by Shimadzu Corporation) is used. Then, the tensile yield strength was measured, and the retention rate (tensile strength retention rate) with respect to the tensile yield strength of the test piece before immersion was determined and used as an index of LLC resistance. Higher tensile strength retention (upper limit 100%) means better LLC resistance.

  In the following Examples and Comparative Examples, the following polyamide resins (A, D), aliphatic or alicyclic carbodiimide (B), and modified polyolefin (C) were used.

<Polyamide resin (A)>
PA9T; The molar ratio of terephthalic acid unit, 1,9-nonanediamine unit and 2-methyl-1,8 octanediamine unit (1,9-nonanediamine unit: 2-methyl-1,8-octanediamine unit is 60:40). The intrinsic viscosity [η] (measured in concentrated sulfuric acid at 30 ° C.) is 1.40 dl / g, the melting point is 276 ° C., and the end-capping rate is 90% or more (end-capping agent: benzoic acid). Polyamide resin

<Aliphatic or alicyclic carbodiimide (B)>
Commercially available carbodiimide (Carbodilite LA-1, manufactured by Nisshinbo Industries, Inc.)

<Modified polyolefin (C)>
Commercially modified polyolefin (EPR T7761P, manufactured by JSR)

<Polyamide resin (D)>
PA12; UBE3024, manufactured by Ube Industries, Ltd.

Examples 1-4
After blending the polyamide resin (A) and the aliphatic or cycloaliphatic carbodiimide (B) in the proportions shown in Table 1, the mixture was twin screw extruder (screw diameter 30 mm, L / D = 28, cylinder temperature 310 to 330 ° C. The polyamide resin composition was obtained by melt-kneading using a rotating speed of 150 rpm. About the obtained polyamide resin composition, LLC resistance was tested and evaluated by said method. The obtained results are shown in Table 1 below.

Example 5
After blending polyamide resin (A), aliphatic or cycloaliphatic carbodiimide (B), and modified polyolefin (C) in the proportions shown in Table 1, the mixture was twin screw extruder (screw diameter 30 mm, L / D = 28, A polyamide resin composition was obtained by melt kneading using a cylinder temperature of 310 to 330 ° C. and a rotation speed of 150 rpm. About the obtained polyamide resin composition, LLC resistance was tested and evaluated by said method. The obtained results are shown in Table 1 below.

Comparative Examples 1-3
As shown in Table 1, the polyamide resin (A) or the polyamide resin (D) is used alone, or the polyamide resin (A) and the modified polyolefin (C) are mixed in the ratio shown in Table 1 to obtain a resin composition. Obtained. The LLC resistance of these resins and resin compositions was evaluated by the above method. The obtained results are shown in Table 1.

  As can be seen from Table 1, the dicarboxylic acid unit (a) containing terephthalic acid units in the range of 50 to 100 mol% and the aliphatic alkylenediamine units having 6 to 18 carbon atoms in the range of 60 to 100 mol%. Aliphatic or alicyclic with respect to 100 parts by mass of polyamide resin (A) having a diamine unit (b) and having an intrinsic viscosity of 0.6 to 2.0 dl / g measured in concentrated sulfuric acid at 30 ° C. The polyamide resin compositions of Examples 1 to 5 containing the formula carbodiimide (B) in the range of 0.01 to 20 parts by mass have a tensile strength retention of about 80% even after being immersed in LLC resistance for 2000 hours. The level was maintained, and very good LLC resistance was exhibited.

  On the other hand, about the polyamide resin, in the case of the comparative example 1 which uses the same thing as Examples 1-5 (polyamide resin (A)), since it does not contain an aliphatic or alicyclic carbodiimide (B), it is about 80% This level of LLC resistance could not be maintained for 2000 hours. In addition, in the case of Comparative Example 2 in which not only the aliphatic or alicyclic carbodiimide (B) was used but also the polyamide resin (D) different from Examples 1 to 5, the level of about 80% was used. LLC resistance could not be maintained for 1000 hours. Further, in the case of Comparative Example 3 in which the modified polyolefin (C) is used instead of the aliphatic or alicyclic carbodiimide (B) for the polyamide resin (A), the LLC resistance of about 80% is also achieved. I couldn't keep time.

The polyamide resin composition of the present invention is excellent in oil resistance, water resistance, halogenated metal salt, and excellent in hydrolysis resistance in an acidic medium at high temperature, so electrical / electronic parts, mechanical parts, It is useful as a raw material for molded products such as daily and leisure goods, building materials, industrial materials and packaging materials. In particular, since it is excellent in hydrolysis resistance in an acidic medium at high temperature, it is useful as a member used for a portion that comes into contact with an automobile fluid.

Claims (9)

  It consists of a dicarboxylic acid unit (a) containing 50 to 100 mol% of terephthalic acid units and a diamine unit (b) containing 60 to 100 mol% of aliphatic alkylenediamine units having 6 to 18 carbon atoms. 0.01 to 20 parts by mass of an aliphatic or alicyclic carbodiimide (B) with respect to 100 parts by mass of the polyamide resin (A) having an intrinsic viscosity of 0.6 to 2.0 dl / g measured under the condition of ° C. A polyamide resin composition comprising:   The polyamide resin composition according to claim 1, wherein the aliphatic alkylenediamine unit having 6 to 18 carbon atoms is a 1,9-nonanediamine unit and / or a 2-methyl-1,8-octanediamine unit.   The polyamide resin composition according to claim 2, wherein the molar ratio of the 1,9-nonanediamine unit to the 2-methyl-1,8-octanediamine unit is 95/5 to 50/50.   The polyamide resin composition according to any one of claims 1 to 3, wherein 10% or more of the end groups of the molecular chain of the polyamide resin (A) are sealed with an end-capping agent.   The polyamide resin composition according to any one of claims 1 to 4, wherein the aliphatic or alicyclic carbodiimide (B) is dicyclohexylcarbodiimide or diisopropylcarbodiimide.   The polyamide resin composition according to any one of claims 1 to 5, further comprising 1 to 100 parts by mass of a modified polyolefin (C) with respect to 100 parts by mass of the polyamide resin (A).   The molded article which consists of a polyamide resin composition in any one of Claims 1-6.   The molded article according to claim 7, wherein the molded article is an automobile member used in contact with an automobile fluid. The molded article according to claim 7, which is a member used in contact with a coolant.