JP2010202724A - Piping for automobiles - Google Patents

Abstract

[PROBLEMS] To be formed from a polyamide composition which is excellent in various properties such as low water absorption, heat resistance, slidability, chemical resistance, gasoline barrier property and the like, and excellent in melt stability in which foaming does not occur even by an extrusion molding method. Providing automotive piping with excellent long-term heat aging resistance.
[MEANS FOR SOLVING PROBLEMS] A modified polyolefin (B) with respect to 100 parts by mass of a polyamide (A) having an intrinsic viscosity measured in concentrated sulfuric acid at 30 ° C of 0.6 to 2.0 dl / g and a melting point of 260 ° C or higher. 1 to 30 parts by mass, from 0.005 to 0.025 parts by mass of a copper compound (C) in terms of copper atoms, and from a polyamide composition comprising 0.2 to 10 parts by mass of an organic stabilizer (D) Automotive piping formed.
[Selection figure] None

Description

  The present invention relates to automobile piping such as fuel piping and cooling piping, which is formed from a polyamide composition excellent in melt stability and excellent in long-term heat aging resistance.

  A polyamide having a melting point of 260 ° C. or higher has been conventionally used as a material for producing a resin molded product requiring heat resistance. In addition, in order to improve heat aging resistance and the like, for example, a technique is known in which a copper compound is blended with a semi-aromatic polyamide, or an organic compound or a functionalized polyolefin is blended together with a copper compound (Patent Documents 1 to 3). 3).

A technique is also known in which a polyamide compound, a modified polyolefin, and an organic stabilizer are used in combination with polyamide. For example, as a polyamide composition excellent in heat aging resistance without causing foaming or discoloration even at a high temperature exceeding 280 ° C., a specific semi-aromatic polyamide, a graft-modified product such as a graft-modified α-olefin polymer, and a copper compound And a polyamide composition comprising a masterbatch comprising a low melting point polyamide containing an alkali metal halide (see Patent Document 4). Patent Document 4 describes that an organic stabilizer can be blended for the purpose of improving thermal stability, preventing oxidation, and improving light stability.
Further, it is known that a polyamide composition containing a specific polyamide, modified polyolefin, copper compound, halogenated alkali metal compound and organic stabilizer is excellent in heat aging resistance and the like (see Patent Documents 5 and 6). .
In addition, a composition comprising a specific partially aromatic polyamide, an olefinic impact modifier, a specific copper-containing thermal stabilizer, and a compound selected from secondary arylamines and hindered phenols, during injection molding, It is known to reduce the deposit rate of mold deposits and show excellent thermal stability, thereby extending the cleaning interval of the mold and reducing the occurrence of burned or discolored molded products. (See Patent Document 7).

  Incidentally, automobile piping such as fuel piping and cooling piping is usually manufactured by an extrusion molding method. When manufacturing automobile pipes by extrusion molding using polyamide, it is desirable to use polyamide with high melt viscosity because it is necessary to increase the melt tension of the molten resin to some extent in order to ensure moldability. It is. However, when a polyamide having a high melt viscosity is used, the molten resin tends to generate shear heat in the extrusion molding machine, and the deterioration of the molten resin becomes severe. In particular, when a copper compound is blended in the molten resin, the copper compound acts as a decarboxylating agent for the polyamide to accelerate the deterioration of the polyamide and generate bubbles in the molten resin, which is the automobile that is the final product. It will remain in the service pipe. If such bubbles remain in the automobile piping, destruction based on the bubbles tends to occur, and the product may have a significantly reduced mechanical strength. Therefore, an automobile pipe formed from a polyamide composition excellent in melt stability in which foaming does not occur even by an extrusion molding method is desired.

Japanese Patent Laid-Open No. 61-285252 JP-A 63-105057 JP-T 8-503274 JP 2000-239523 A JP 2000-319507 A JP 2000-319508 A Special table 2003-503534 gazette

  The present invention is formed from a polyamide composition which is excellent in various properties such as low water absorption, heat resistance, slidability, chemical resistance and gasoline barrier properties and excellent in melt stability in which foaming does not occur even by an extrusion method. An object of the present invention is to provide a piping for automobiles that is also excellent in long-term heat aging resistance.

  As a result of intensive studies to achieve the above-mentioned object, the inventors of the present invention have produced a modified polyolefin, a copper compound, When the polyamide composition obtained by blending a specific amount of each of the organic stabilizer and the organic stabilizer is used, it was found that the intended automobile piping can be obtained, and further studies were made to complete the present invention.

That is, the present invention
[1] The modified polyolefin (B) is added to 100 parts by mass of the polyamide (A) having an intrinsic viscosity measured in concentrated sulfuric acid at 30 ° C. of 0.6 to 2.0 dl / g and a melting point of 260 ° C. or higher. Formed from a polyamide composition comprising 1 to 30 parts by mass, copper compound (C) 0.005 to 0.025 parts by mass in terms of copper atoms, and organic stabilizer (D) 0.2 to 10 parts by mass Automotive piping,
[2] The automobile pipe according to the above [1], wherein the intrinsic viscosity measured at 30 ° C. in the concentrated sulfuric acid of the polyamide (A) is 1.0 to 2.0 dl / g,
[3] The above [1], wherein the polyamide (A) has a dicarboxylic acid unit containing 30 to 100 mol% of a terephthalic acid unit and a diamine unit containing 50 to 100 mol% of an aliphatic diamine unit having 6 to 18 carbon atoms. ] Or [2] automotive piping,
[4] The automotive piping according to the above [3], wherein the aliphatic diamine unit having 6 to 18 carbon atoms is a 1,9-nonanediamine unit and / or a 2-methyl-1,8-octanediamine unit,
[5] The automobile piping according to any one of the above [1] to [4], wherein the organic stabilizer (D) is a hindered phenol stabilizer,
[6] The automobile piping according to any one of [1] to [5], wherein the polyamide composition further contains an alkali metal halide,
[7] The automobile pipe according to any one of the above [1] to [6], wherein the automobile pipe is a fuel system pipe or a cooling system pipe;
About.

  According to the present invention, the polyamide composition is excellent in various properties such as low water absorption, heat resistance, slidability, chemical resistance, gasoline barrier properties, etc., and excellent in melt stability in which foaming does not occur even by an extrusion molding method. An automotive piping that is formed and has excellent long-term heat aging resistance is provided.

  The automobile pipe of the present invention is modified with respect to 100 parts by mass of polyamide (A) having an intrinsic viscosity of 0.6 to 2.0 dl / g measured in concentrated sulfuric acid at 30 ° C. and a melting point of 260 ° C. or higher. 1-30 parts by mass of polyolefin (B), 0.005-0.025 parts by mass of copper compound (C) in terms of copper atoms, and 0.2-10 parts by mass of organic stabilizer (D) It is formed from a polyamide composition.

  The polyamide (A) used in the present invention has an intrinsic viscosity of 0.6 to 2.0 dl / g measured in concentrated sulfuric acid at 30 ° C. and a melting point of 260 ° C. or higher. Examples of such polyamide (A) include aliphatic polyamides such as PA46 and PA66, dicarboxylic acid units containing 30 to 100 mol% of terephthalic acid units, and aliphatic diamine units having 6 to 18 carbon atoms and 50 to 100 mols. And polyamides (semi-aromatic polyamides) having a diamine unit containing%. Of these, semi-aromatic polyamides are preferred in terms of heat resistance and low water absorption.

  The dicarboxylic acid unit in the semi-aromatic polyamide is a terephthalic acid unit in the range of 30 to 100 mol%, preferably 60 to 100 mol%, more preferably 75 to 100 mol%, and still more preferably 90 to 100 mol%. Contains. When the content of the terephthalic acid unit in the dicarboxylic acid unit is in the above range, an automobile pipe having better heat resistance can be obtained.

  The dicarboxylic acid unit in the semi-aromatic polyamide is 70 mol% or less, preferably 40 mol% or less, more preferably 25 mol% or less, still more preferably 10 mol% or less, and other than terephthalic acid units. Dicarboxylic acid units may be included. Examples of 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, Aliphatic dicarboxylic acids such as 2-diethylsuccinic 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'-biphenyl Can be mentioned units derived from an aromatic dicarboxylic acid such as carboxylic acids, it can include one or more of them. Of these, units derived from aromatic dicarboxylic acids are preferred. The semi-aromatic polyamide may further contain a unit derived from a polyvalent carboxylic acid such as trimellitic acid, trimesic acid, and pyromellitic acid as long as melt molding is possible.

  The diamine unit in the semi-aromatic polyamide is an aliphatic diamine unit having 6 to 18 carbon atoms in an amount of 50 to 100 mol%, preferably 60 to 100 mol%, more preferably 75 to 100 mol%, further preferably 90 to 90 mol%. It contains in the range of 100 mol%. When the content of the aliphatic diamine unit having 6 to 18 carbon atoms in the diamine unit is in the above range, an automobile pipe having excellent physical properties such as heat resistance, low water absorption, and chemical resistance can be obtained.

  Examples of the aliphatic diamine unit having 6 to 18 carbon atoms include 1,6-hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, 1,9-nonanediamine, and 1,10-decanediamine. Linear aliphatic diamines such as 1,11-undecanediamine and 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-1,6-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-octanediamine, 2,4- Methyl-1,8-octanediamine, 3,4-dimethyl-1,8-octanediamine, 4,5-dimethyl-1,8-octanediamine, 2,2-dimethyl-1,8-octanediamine, 3, Examples include units derived from branched aliphatic diamines such as 3-dimethyl-1,8-octanediamine, 4,4-dimethyl-1,8-octanediamine, and 5-methyl-1,9-nonanediamine. Of these, one or more of these may be included.

  The aliphatic diamine unit having 6 to 18 carbon atoms is a polyamide composition excellent in toughness, slidability, heat resistance, moldability, low water absorption, lightness, etc., and further toughness, slidability, heat resistance, Since an automobile pipe excellent in low water absorption and light weight can be obtained, 1,6-hexanediamine, 1,8-octanediamine, 2-methyl-1,8-octanediamine, 1,9-nonanediamine, It is preferably a unit derived from at least one diamine selected from the group consisting of 1,10-decanediamine, 1,11-undecanediamine and 1,12-dodecanediamine, and includes 1,9-nonanediamine unit and / or Alternatively, it is more preferably a 2-methyl-1,8-octanediamine unit.

  In the case where a 1,9-nonanediamine unit and a 2-methyl-1,8-octanediamine unit are used in combination, the mole between the 1,9-nonanediamine unit and the 2-methyl-1,8-octanediamine unit. The ratio is that if the content of 1,9-nonanediamine units is too large, the toughness may be impaired, so that 1,9-nonanediamine units: 2-methyl-1,8-octanediamine units = 30: 70-90. Is preferably in the range of 10:10, more preferably in the range of 40:60 to 70:30, and even more preferably in the range of 45:55 to 60:40.

  The diamine unit in the semi-aromatic polyamide is an aliphatic group having 6 to 18 carbon atoms in a proportion of 50 mol% or less, preferably 40 mol% or less, more preferably 25 mol% or less, and even more preferably 10 mol% or less. Other diamine units other than the diamine unit may be included. Examples of such other diamine units include aliphatic diamines such as ethylenediamine, 1,2-propanediamine, 1,3-propanediamine, 1,4-butanediamine, and 1,5-pentanediamine; cyclohexanediamine and methylcyclohexane. Alicyclic diamines such as diamine and isophoronediamine; p-phenylenediamine, m-phenylenediamine, xylylenediamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylsulfone, 4,4′-diaminodiphenylether, etc. The unit derived from the aromatic diamine or the like may be included, and one or more of these may be included.

  Moreover, said semi-aromatic polyamide may contain an aminocarboxylic acid unit. Examples of the aminocarboxylic acid unit include units derived from lactams such as caprolactam and lauryllactam; aminocarboxylic acids such as 11-aminoundecanoic acid and 12-aminododecanoic acid. The content of aminocarboxylic acid units in the semiaromatic polyamide is preferably 40 mol% or less, and more preferably 20 mol% or less, based on all dicarboxylic acid units of the semiaromatic polyamide.

  In order to impart better melt stability and hot water resistance to the polyamide composition, the above semi-aromatic polyamide is 10% or more, more preferably 40% or more, more preferably 60% of the end groups of the molecular chain. The above is preferably sealed with a terminal sealing agent.

The end-capping rate of the above semi-aromatic polyamide is 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 semi-aromatic polyamide. And can be obtained according to the following equation. Here, the number of each terminal group is preferably determined by ¹ H-NMR based on the integral value of the characteristic signal corresponding to each terminal group in terms of accuracy and simplicity.

Terminal sealing rate (%) = [(A−B) / A] × 100
[Wherein A represents the total number of end groups of the molecular chain of the semi-aromatic polyamide (this is usually equal to twice the number of polyamide molecules), B is the remaining carboxyl group ends and amino Represents the total number of base ends. ]

  As the end-capping agent, a monofunctional compound having reactivity with the terminal amino group or carboxyl group can be used. From the viewpoint of reactivity and stability of the capped end, monocarboxylic acid is used. 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, monoacid halides, monoesters, monoalcohols, and the like can also be used as the end-capping agent.

  The monocarboxylic acid that can be used as the end-capping agent is not particularly limited as long as it has reactivity with an amino group. For example, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid , Lauric acid, tridecanoic acid, myristic acid, palmitic acid, stearic acid, pivalic acid, isobutyric acid and other aliphatic monocarboxylic acids; cyclohexanecarboxylic acid and other alicyclic monocarboxylic acids; benzoic acid, toluic acid, α-naphthalene Examples thereof include aromatic monocarboxylic acids such as carboxylic acid, β-naphthalene carboxylic acid, methyl naphthalene carboxylic acid, and phenyl acetic acid; any mixtures thereof. Among these, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, lauric acid, tridecanoic acid, myristic acid, palmitic acid, stearin, etc. Acid and benzoic acid are preferred.

  The monoamine that can be used as the end-capping agent is not particularly limited as long as it has reactivity with a carboxyl group. For example, methylamine, ethylamine, propylamine, butylamine, hexylamine, octylamine, decylamine , Stearylamine, dimethylamine, diethylamine, dipropylamine, dibutylamine and other aliphatic monoamines; cyclohexylamine, dicyclohexylamine and other alicyclic monoamines; aniline, toluidine, diphenylamine, naphthylamine and other aromatic monoamines; any of these A mixture etc. can be mentioned. Among these, butylamine, hexylamine, octylamine, decylamine, stearylamine, cyclohexylamine, and aniline are preferable from the viewpoints of reactivity, boiling point, stability of the sealing end, price, and the like.

  The polyamide (A) used in the present invention can be produced, for example, using any method known as a method for producing crystalline polyamide. Specifically, 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. it can.

  When the polyamide (A) is produced by various polymerization methods, in addition to the above-described end capping agent, for example, phosphoric acid, phosphorous acid, hypophosphorous acid, salts or esters thereof are polymerized as a catalyst. Can be added. 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 of phosphoric acid, phosphorous acid or hypophosphorous acid; phosphoric acid, phosphorous acid or hypophosphorous acid ethyl ester, isopropyl ester, butyl ester, hexyl ester, isodecyl ester, octadecyl ester, decyl Examples thereof include esters, stearyl esters, and phenyl esters.

  The intrinsic viscosity [η] measured at 30 ° C. in the concentrated sulfuric acid of the polyamide (A) used in the present invention is in the range of 0.6 to 2.0 dl / g. If the intrinsic viscosity is too low, the mechanical properties of the resulting polyamide composition and thus the automotive piping formed therefrom are excessively lowered, and the melt tension is low, making it difficult to produce automotive piping. On the other hand, if the intrinsic viscosity is too high, the fluidity of the resulting polyamide composition is excessively lowered and the moldability tends to deteriorate. From the viewpoint of the mechanical properties of the resulting automobile pipe and the moldability when producing the automobile pipe, the intrinsic viscosity measured at 30 ° C. in the concentrated sulfuric acid of the polyamide (A) is 1.0 to 2.0 dl / g. It is preferably within the range, and more preferably within the range of 1.0 to 1.8 dl / g.

  The melting point of the polyamide (A) used in the present invention is 260 ° C. or higher, preferably in the range of 260 to 340 ° C., more preferably in the range of 260 to 320 ° C., and 260 to More preferably, it is within the range of 290 ° C. When the polyamide (A) has a melting point in the above range, a highly heat-resistant automobile pipe can be produced. On the other hand, if the melting point of the polyamide (A) is too high, it is necessary to increase the processing temperature, and foaming due to thermal degradation of the polyamide is likely to occur. The melting point in the present specification is a value measured by a differential scanning calorimeter (DSC) as will be described later in Examples.

  The polyamide composition forming the automobile pipe of the present invention contains a modified polyolefin (B). When the polyamide composition contains the modified polyolefin (B), the melt stability of the polyamide (A) contained in the polyamide composition is improved. As the modified polyolefin (B), a modified polyolefin obtained by modifying a polyolefin with an α, β-unsaturated carboxylic acid or an α, β-unsaturated carboxylic acid derivative such as an ester, acid anhydride or metal salt thereof is used. Among them, a modified polyolefin produced by copolymerizing an α, β-unsaturated carboxylic acid or an α, β-unsaturated carboxylic acid derivative when producing a polyolefin, or an α, β-unsaturated carboxylic acid Alternatively, a modified polyolefin produced by grafting an α, β-unsaturated carboxylic acid derivative onto the polyolefin can be preferably used. Specific examples of polyolefins constituting the basic skeleton of these modified polyolefins include, for example, ethylene / propylene copolymers, ethylene / 1-butene copolymers, ethylene / 4-methyl-1-pentene copolymers, ethylene / propylene copolymers, 1-hexene copolymer, ethylene / 1-octene copolymer, ethylene / 1-decene copolymer, propylene / 1-butene 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, ethylene / 1- , And the like Ten 5-ethylidene-2-norbornene copolymer. Examples of the α, β-unsaturated carboxylic acid include acrylic acid, methacrylic acid, α-ethylacrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, tetrahydrophthalic acid, methyltetrahydrophthalic acid, and endocis-bicyclo. [2.2.1] hept-5-ene-2,3-dicarboxylic acid (nadic acid (trade name)) and methyl-endocis-bicyclo [2.2.1] hept-5-ene-2, 3-dicarboxylic acid (methyl nadic acid (trade name)) and the like. Modified polyolefin (B) may be used individually by 1 type, or may use 2 or more types together.

  Among the above-mentioned modified polyolefins (B), the resulting polyamide composition, and hence the automobile piping formed therefrom, is more excellent in impact resistance, so that an ethylene / propylene copolymer, ethylene / 1-butene is obtained. It is preferable to use a modified polyolefin having a basic skeleton of an ethylene / α-olefin copolymer such as a copolymer or an ethylene / 4-methyl-1-pentene copolymer, and the ethylene / α-olefin copolymer is anhydrous. It is more preferable to use a modified polyolefin modified with maleic acid.

  If the content of the modified polyolefin (B) contained in the polyamide composition forming the automobile pipe of the present invention is too small, the effect of improving the melt stability of the polyamide (A) is not sufficient, and if it is too much, the automobile is obtained. Since the mechanical strength of the piping for use decreases, it is in the range of 1 to 30 parts by mass, preferably in the range of 1 to 20 parts by mass, with respect to 100 parts by mass of the polyamide (A). More preferably, it is within the range of 20 parts by mass, and even more preferably within the range of 3 to 15 parts by mass.

  The polyamide composition forming the automobile pipe of the present invention contains a copper compound (C). When the polyamide composition contains the copper compound (C), it is possible to obtain an automobile pipe having improved long-term heat aging resistance.

  Examples of the copper compound (C) include cuprous chloride, cuprous bromide, cuprous iodide, cupric chloride, cupric bromide, cupric iodide, cupric phosphate, Inorganic copper compounds such as cupric pyrophosphate, copper sulfide, and copper nitrate; copper salts of organic carboxylic acids such as copper acetate can be used. These copper compounds (C) may be used individually by 1 type, or may use 2 or more types together.

  If the content of the copper compound (C) contained in the polyamide composition is too small, it will be difficult to ensure the heat aging resistance of the resulting automotive pipe, and if it is too large, foaming during molding becomes significant. Since the mechanical strength of the automobile piping is reduced by remaining in the automobile piping from which bubbles are obtained, the amount is within the range of 0.005 to 0.025 parts by mass in terms of copper atoms with respect to 100 parts by mass of the polyamide (A). It is preferably within a range of 0.010 to 0.025 parts by mass, and more preferably within a range of 0.010 to 0.020 parts by mass.

Further, the polyamide composition preferably contains an alkali metal halide because an automobile pipe having further excellent heat resistance can be obtained. Specific examples of the alkali metal halide include, for example, lithium chloride, lithium bromide, lithium iodide, lithium fluoride, sodium chloride, sodium bromide, sodium iodide, sodium fluoride, potassium chloride, potassium bromide, iodine And potassium fluoride and potassium fluoride. Of these, potassium iodide is particularly preferred. These alkali metal halides may be used alone or in combination of two or more.
The content of the alkali metal halide in the polyamide composition is preferably in the range of 0.25 to 1 part by mass with respect to 100 parts by mass of the polyamide (A), More preferably within the range.

  The polyamide composition forming the automobile pipe of the present invention contains an organic stabilizer (D). When the polyamide composition contains the organic stabilizer (D), not only the heat aging resistance of the automobile pipe is improved, but also the melt stability of the polyamide (A) is improved.

Examples of the organic stabilizer (D) include hindered phenol stabilizers, amine stabilizers, phosphorus stabilizers, thioether stabilizers, and the like, one or more of these. Can be used.
Examples of the hindered phenol stabilizer include octadecyl 3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, pentaerythrityl-tetrakis [3- (3,5-di-t- Butyl-4-hydroxyphenyl) propionate], 3,9-bis [2- [3- (3-t-butyl-4-hydroxy-5-methylphenyl) propionyloxy] -1,1-dimethylethyl]- 2,4,8,10-tetraoxaspiro [5.5] undecane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene 1,3,5-tris [ethylene-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] -s-triazine-2,4,6- (1H, 3H, 5 ) Trione, 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 4,4′-methylene-bis (2,6-di-tert-butylphenol), hexamethylene Glycol-bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], bis [2- [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate Roxy] ethyl] sulfide, 2,2′-methylene-bis (4-methyl-6-t-nonylphenol) and the like.
Examples of the amine stabilizer include 1,2,2,6,6-pentamethyl-4-piperidyl stearate, 2,2,6,6-tetramethyl-4-piperidylbenzoate, N- [12- ( 2,2,6,6-tetramethyl-4-piperidyl)] dodecylsuccinimide, 1-[(3,5-di-t-butyl-4-hydroxyphenyl) propionyloxyethyl] -2,2,6 , 6-Tetramethyl-4-piperidyl (3,5-di-t-butyl-4-hydroxyphenyl) propionate, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, tetra (2, 2,6,6-tetramethyl-4-piperidyl) butanetetracarboxylate, tetra (1,2,2,6,6-pentamethyl-4-piperidyl) butanetetracarboxylate Bis (2,2,6,6-tetramethyl-4-piperidyl) ditridecyl butane tetracarboxylate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) ditridecyl butane tetracarboxylate, etc. Is mentioned.
Examples of the phosphorus stabilizer include triphenyl phosphite, diphenyl phosphite, didecyl phenyl phosphite, tridecyl phosphite, trioctyl phosphite, tridodecyl phosphite, trioctadecyl phosphite, and trinonyl phenyl phosphite. , Tridodecyl trithiophosphite, distearyl pentaerythritol diphosphite, 4,4′-butylidenebis (3-methyl-6-tert-butylphenyl) bis (ditridecyl phosphite), tris (2,4-di-t -Butylphenyl) phosphite, bis (2,4-di-t-butylphenyl) pentaerythritol diphosphite, 4,4'-isopropylidenediphenyltetraalkyldiphosphite (the alkyl group has 12 to 15 carbon atoms) Phospha etc. G; phosphonite such as tetrakis (2,4-dialkylphenyl) -4,4′-biphenylenediphosphonite (the alkyl group has 1 to 30 carbon atoms); 4-hydroxy-3,5-di-t-butylbenzyl Phosphonic acid, O-ethyl- (4-hydroxy-3,5-di-t-butylbenzyl) phosphonic acid, O- (2-ethylhexyl)-(4-hydroxy-3,5-di-t-butylbenzyl) Examples include phosphonic acid derivatives such as phosphonic acid and calcium salt of O-ethyl- (4-hydroxy-3,5-di-t-butylbenzyl) phosphonic acid.
Examples of the thioether stabilizer include bis [2-methyl-4- (3-n-alkylthiopropionyloxy) -5-t-butylphenyl] sulfide. Among these organic stabilizers, hindered phenol stabilizers are preferable.

  If the content of the organic stabilizer (D) contained in the polyamide composition is too small, the effect of improving the heat aging resistance of the piping for automobiles and the melt stability of the polyamide (A) is small. Since it leads to the bleeding out of the organic stabilizer (D) to the piping surface and the manufacturing cost increase, it is in the range of 0.2 to 10 parts by mass with respect to 100 parts by mass of the polyamide (A), and 0.4 to It is preferably within the range of 8 parts by mass.

  The polyamide composition may be the above polyamide (A), modified polyolefin (B), copper compound (C) and organic stabilizer (D) alone, or polyamide (A), modified polyolefin (B), copper compound (C). ), May consist of only an alkali metal halide and an organic stabilizer (D), but contains various fillers as necessary in addition to the above-mentioned components in order to improve mechanical strength and the like. Also good. Examples of such fillers include inorganic powder fillers such as silica, alumina, talc, kaolin, quartz, glass, mica, and graphite; inorganic fibers such as glass fiber, carbon fiber, ceramic fiber, and asbestos fiber. These fillers may be used alone or in combination of two or more. The content of the filler contained in the polyamide composition is preferably in the range of 0.1 to 20 parts by mass, preferably in the range of 1 to 10 parts by mass with respect to 100 parts by mass of the polyamide (A). Is more preferable.

  In addition, the polyamide composition is an aliphatic polyamide such as PA612 (polyhexamethylenedodecanamide), PA12 (polydodecanamide) and the like that does not correspond to the polyamide (A); PA6T (polyhexamethylene terephthalamide) , PA66T (polyamide consisting of hexamethylenediamine, adipic acid and terephthalic acid) and other semi-aromatic polyamides not corresponding to the above polyamide (A); among the polyolefins such as polyethylene, polypropylene and EPDM, the above modified polyolefin (B) Not conforming to; polystyrene, butadiene-styrene copolymer, styrene-ethylene / butene-styrene copolymer, styrene-based polymer such as acrylonitrile-butadiene-styrene copolymer (ABS); (meth) acrylic resin; Riesuteru; polycarbonates; polysulfones; polyethersulfones; polyimides; polyetheretherketone; polyoxymethylene; polyphenylene sulfide; polyphenylene ether; may include one or more other types polymers such as polyarylate. The content of the other polymer contained in the polyamide composition is preferably in the range of 1 to 20 parts by mass and preferably in the range of 3 to 10 parts by mass with respect to 100 parts by mass of the polyamide (A). More preferred.

  In addition to the above-described components as necessary, the polyamide composition described above may include a heat stabilizer, an antioxidant, an ultraviolet absorber, a light stabilizer, a plasticizer, a lubricant, a crystal nucleating agent, an antistatic agent, and a flame retardant. 1 type, or 2 or more types of other components, such as a pigment and dye. It is preferable that the content rate of the said other component contained in a polyamide composition exists in the range of 0.01-5 mass parts with respect to 100 mass parts of polyamide (A), and the range of 0.05-3 mass parts More preferably, it is within.

  In the polyamide composition, the proportion of the total mass of polyamide (A), modified polyolefin (B), copper compound (C) and organic stabilizer (D) is in the range of 50 to 100% by mass. It is preferable that it is in the range of 80 to 100% by mass, more preferably in the range of 95 to 100% by mass.

  The polyamide composition is composed of polyamide (A), modified polyolefin (B), copper compound (C), organic stabilizer (D), and, if necessary, the above-described alkali metal halide, filler, etc. The seed polymer and other components can be produced by uniformly mixing them by a known method such as melt kneading. 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 and melt kneading conditions used at that time are not particularly limited, For example, the above-mentioned polyamide composition can be obtained by kneading at a temperature in the range of about 280 to 350 ° C. for 1 to 30 minutes.

The automobile piping of the present invention is formed from the polyamide composition described above. The shape of the automobile pipe of the present invention can be appropriately set according to the intended application. For example, the outer diameter is in the range of 4 to 40 mm, and the inner diameter is in the range of 3 to 39 mm. It can be. In addition, the pipe wall of the automobile pipe of the present invention may have a straight shape without a corrugated area or may have a corrugated area. The corrugated area may be formed over the entire length of the automobile pipe, or may be partially formed in an appropriate area in the middle. The corrugated region is a region formed in a corrugated shape, a bellows shape, an accordion shape, a corrugated shape, or the like. By having such a corrugated region, the shock absorption is improved and the attachment is easy. In addition, the automobile piping of the present invention can be formed into L-shaped, U-shaped, or the like by adding necessary parts such as connectors or by bending.
The automobile pipe of the present invention may have a single layer structure made of the above polyamide composition, but has a laminated structure in which a layer made of another kind of material is laminated on the layer made of the above polyamide composition. You may have. Other types of materials in this case include, for example, polyolefin resins, polyester resins, polyether resins, polysulfone resins, polythioether resins, polyketone resins, polynitrile resins, polymethacrylate resins, polyvinyl acetate resins. Examples include resins, polyvinyl chloride resins, cellulose resins, fluorine resins, polycarbonate resins, thermoplastic polyurethane resins, polyamide resins, and the like. Among these, polyolefin resins, polyester resins, polythioether resins, fluorine resins, and polyamide resins are preferably used.

  Although the manufacturing method in particular of the piping for motor vehicles of this invention is not restrict | limited, The method of extruding the above-mentioned polyamide composition in a pipe shape using an extruder can be employ | adopted preferably. The cylinder temperature of the extruder is preferably 10 to 60 ° C. higher than the melting point of the polyamide.

  The automotive piping of the present invention can be used for various automotive piping applications, and is excellent in various properties such as low water absorption, heat resistance, slidability, chemical resistance, gasoline barrier properties, and extrusion molding. No deterioration in mechanical strength due to bubbles derived from foaming at the time of molding by forming from a polyamide composition excellent in melt stability that does not cause foaming, and also excellent in heat aging resistance, Oil used for transporting various types of oil such as engine cooling oil, brake oil, power steering oil, etc., including automotive cooling system piping that tends to be hot and fuel system piping that requires gasoline barrier properties. It can be preferably used as a system pipe or an air conditioner system pipe.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. In the following examples and comparative examples, the measurement of the melting point of the polyamide (A), the measurement of the intrinsic viscosity of the polyamide (A), the preparation of a test piece, the evaluation of heat aging resistance, and the evaluation of extrusion moldability are described below. I went to do it.

Measurement of melting point of polyamide (A) Using a differential scanning calorimeter (DSC), polyamide (A) (sample weight 10 mg) was heated in a DSC furnace at 330 ° C. for 2 minutes in a nitrogen atmosphere. After completely melting, the mixture was cooled to 50 ° C. at a rate of −50 ° C./min, and the position of the melting peak of the crystal that appeared when the temperature was raised again at a rate of 10 ° C./min was measured. When there were a plurality of peaks, the melting point on the high temperature side was adopted.

A concentrated sulfuric acid solution of polyamide (A) having a measured concentration of the intrinsic viscosity of polyamide (A) of 0.05 g / dl, 0.1 g / dl, 0.2 g / dl and 0.4 g / dl was prepared. About the concentrated sulfuric acid solution, the solution viscosity in 30 degreeC was measured using the Ubbelohde viscometer. From the relationship between the obtained concentration and the solution viscosity, the solution viscosity when extrapolated to a concentration of 0 g / dl was determined, and this was defined as the intrinsic viscosity [η].

Preparation of test piece Using the polyamide composition pellets obtained in the following examples or comparative examples, using an 80-ton injection molding machine manufactured by Nissei Plastic Industry Co., Ltd., cylinder temperature 300 ° C. and mold temperature 150 An ISO multipurpose test piece A for evaluation of heat aging resistance was produced under the condition of ° C.

Evaluation of heat aging resistance The test piece prepared as described above was heat-treated in a hot air dryer at a temperature of 170 ° C. for 500 hours, and then an autograph (manufactured by Shimadzu Corporation) at a temperature of 23 ° C. according to ISO 527-1. The tensile yield strength was measured and the retention rate (tensile strength retention rate) with respect to the tensile yield strength of the specimen before heat treatment was calculated and used as an index of heat aging resistance.

Evaluation of extrusion moldability Polyamide composition using a polyamide composition pellet obtained in the following examples or comparative examples, using an extruder made by Pla Giken Co., Ltd. under conditions of a cylinder temperature of 300 ° C. When a single-layer pipe (outer diameter: 14 mm, inner diameter: 13 mm) made of a material is molded, and no bubbles are found inside the pipe wall, “○”, bubbles are found inside the pipe wall. In this case, the extrudability was evaluated as “x”.

  In the following Examples and Comparative Examples, the following polyamide (A), modified polyolefin (B), copper compound (C), organic stabilizer (D), alkali metal halide and filler were used.

[Polyamide (A)]
Terephthalic acid unit, 1,9-nonanediamine unit and 2-methyl-1,8-octanediamine unit (1,9-nonanediamine unit: 2-methyl-1,8-octanediamine unit = 50: 50 (molar ratio) The intrinsic viscosity [η] (measured in concentrated sulfuric acid at 30 ° C.) is 1.60 dl / g, the melting point is 265 ° C., and the end capping rate is 90% or more (end capping agent: benzoic acid). polyamide.
[Modified polyolefin (B)]
Made by Mitsui Chemicals, Inc .: “Tafmer MH7020” (trade name), maleic anhydride-modified ethylene-butene copolymer [copper compound (C)]
Wako Pure Chemical Industries, Ltd .: Cuprous iodide [Organic stabilizer (D)]
Manufactured by Sumitomo Chemical Co., Ltd .: “Sumilizer GA-80” (trade name), 3,9-bis [2- [3- (3-t-butyl-4-hydroxy-5-methylphenyl) propionyloxy] -1 , 1-Dimethylethyl] -2,4,8,10-tetraoxaspiro [5.5] undecane (hindered phenol stabilizer)
[Alkali metal halide]
Wako Pure Chemical Industries, Ltd .: Potassium iodide [filler]
Fuji Talc Industrial Co., Ltd .: “PKP-80” (trade name), Talc

[Examples 1-6 and Comparative Examples 1-5]
After premixing polyamide (A), modified polyolefin (B), copper compound (C), organic stabilizer (D), alkali metal halide and filler in the proportions shown in Tables 1 and 2, the resulting mixture Was supplied to a twin-screw extrusion molding machine (manufactured by Pla Giken Co., Ltd.) and melt-kneaded under conditions of a cylinder temperature of 300 to 320 ° C. to obtain a polyamide composition as pellets. About the obtained polyamide composition, heat aging resistance and extrusion moldability were evaluated by the said method. The obtained results are shown in Tables 1 and 2.

  As can be seen from Table 1, Examples 1 to 6 have high tensile strength retention and excellent heat aging resistance, and bubbles are observed inside the pipe wall when the pipe is molded by an extrusion molding machine. The extrusion moldability was also good. On the other hand, as shown in Table 2, since the modified polyolefin (B) is not used in Comparative Examples 1 and 2, the heat aging resistance is poor, and the inside of the pipe wall of the pipe formed by the extrusion molding machine is poor. Bubbles were confirmed and the extrusion moldability was poor. Moreover, although the heat aging resistance was excellent in the comparative example 3 which increased the compounding quantity of the copper compound (C), the extrusion moldability was still bad. In Comparative Example 4, the modified polyolefin (B) and the copper compound (C) were contained in a predetermined amount and the extrusion moldability was good, but since the organic stabilizer was not included, the heat aging resistance was poor. In Comparative Example 5, the modified polyolefin (B), the copper compound (C), and the organic stabilizer (D) are contained, but the content of the copper compound (C) is too large. Bubbles were confirmed inside the tube wall, and the extrusion moldability was poor.

  The automobile pipe of the present invention is excellent in various properties such as low water absorption, heat resistance, slidability, chemical resistance and gasoline barrier property, and also has a polyamide composition excellent in melt stability that does not cause foaming even by an extrusion molding method. Because it is formed from a product, there is no decrease in mechanical strength due to bubbles derived from foaming at the time of molding, and it is also excellent in heat aging resistance. Or it is suitable for the utilization to fuel system piping etc. in which gasoline barrier property is required.

Claims (7)

  The modified polyolefin (B) is added in an amount of 1 to 30 with respect to 100 parts by mass of the polyamide (A) having an intrinsic viscosity of 0.6 to 2.0 dl / g measured in concentrated sulfuric acid at 30 ° C. and a melting point of 260 ° C. or higher. An automobile formed of a polyamide composition containing 0.005 to 0.025 parts by mass of a copper compound (C) in terms of copper atoms and 0.2 to 10 parts by mass of an organic stabilizer (D) in terms of copper atoms. Piping.   The automotive pipe according to claim 1, wherein the intrinsic viscosity of the polyamide (A) measured in concentrated sulfuric acid at 30 ° C is 1.0 to 2.0 dl / g.   The polyamide (A) has dicarboxylic acid units containing 30 to 100 mol% of terephthalic acid units and diamine units containing 50 to 100 mol% of aliphatic diamine units having 6 to 18 carbon atoms. The automotive piping as described.   The automotive piping according to claim 3, wherein the aliphatic diamine unit having 6 to 18 carbon atoms is a 1,9-nonanediamine unit and / or a 2-methyl-1,8-octanediamine unit.   The piping for automobiles according to any one of claims 1 to 4, wherein the organic stabilizer (D) is a hindered phenol stabilizer.   The automobile pipe according to any one of claims 1 to 5, wherein the polyamide composition further contains an alkali metal halide.   The automotive piping according to any one of claims 1 to 6, wherein the automotive piping is a fuel piping or a cooling piping.