Polyamide resin composition

Abstract

The present invention relates to a polyamide resin composition comprising polyamide (X) comprising a diamine unit containing 70 mol % or more of a metaxylylenediamine unit and a dicarboxylic acid unit and an alkali compound (A), wherein the following equations (1) to (4) are satisfied: 10≦([COOH]—[NH 2 ])≦80  (1) 0.32≦P<6.46  (2) 0.50≦M<17.00  (3) 2≦M/P≦3  (4) wherein [COOH] represents a concentration (μeq/g) of a terminal carboxyl group in the polyamide (X); [NH 2 ] represents a concentration (μeq/g) of a terminal amino group in the polyamide (X); P represents a mole concentration (μmol/g) of a phosphorus atom contained per g of the polyamide resin composition; and M represents a sum (μmol/g) of values obtained by multiplying a mole concentration of an alkali metal atom and a mole concentration of an alkaline earth metal atom each contained per g of the polyamide resin composition by valencies thereof respectively.

1 . A polyamide resin composition; comprising:
 a polyamide (X) comprising a diamine unit comprising 70 mol % or more of a metaxylylenediamine unit and a dicarboxylic acid unit; and   an alkali compound (A),   wherein equations (1) to (4) are satisfied:
   10≦([COOH]—[NH 2 ])≦80  (1)
 
   0 32≦P<6.46  (2)
 
   0.50<M<17.00  (3)
 
   2≦M/P≦3  (4)
 
   wherein [COOH] is a concentration (μeq/g) of a terminal carboxyl group in the polyamide (X);   [NH 2 ] is a concentration (μeq/g) of a terminal amino group in the polyamide (X);   P is a mole concentration (μmol/g) of a phosphorus atom contained per gram of the polyamide resin composition; and   M is a sum (μmol/g) of values obtained by multiplying a mole concentration of an alkali metal atom and a mole concentration of an alkaline earth metal atom each contained per gram of the polyamide resin composition by valencies thereof, respectively.   
     
     
         2 . The polyamide resin composition of  claim 1 , wherein the alkali compound (A) is a carboxylate comprising 10 or less carbon atoms of an alkali metal. 
     
     
         3 . The polyamide resin composition of  claim 1 , wherein the polyamide (X) is a polyamide comprising a diamine unit comprising 70 mol % or more of a metaxylylenediamine unit and a dicarboxylic acid unit comprising 70 mol % or more of an adipic acid unit. 
     
     
         4 . The polyamide resin composition of  claim 1 , wherein the polyamide (X) is a polyamide comprising a diamine unit comprising 70 mol % or more of a metaxylylenediamine unit and a dicarboxylic acid unit comprising 70 to 99 mol % of an adipic acid unit and 1 to 30 mol % of an isophthalic acid unit. 
     
     
         5 . The polyamide resin composition of  claim 1 , wherein the polyamide (X) is a polyamide comprising a diamine unit comprising 70 mol % or more of a metaxylylenediamine unit and a dicarboxylic acid unit comprising 70 mol % or more of a sebacic acid unit. 
     
     
         6 . A process for producing the polyamide resin composition of  claim 1 , the process comprising:
 (a) polycondensating a diamine comprising 70 mol % or more of metaxylylenediamine and dicarboxylic acid in the presence of a phosphorus atom-comprising compound (B), to obtain the polyamide (X); and   (b) adding the alkali compound (A) to the polyamide (X).   
     
     
         7 . The process of  claim 6 , wherein, in (a), the polycondensation is carried out in the presence of the phosphorus atom-comprising compound (B) and an alkali metal compound (C). 
     
     
         8 . The process of  claim 6 , wherein the adding (b) comprises:
 (b1) melting and kneading 90 to 99 parts by mass of the polyamide (X) and 10 to 1 part by mass of the alkali compound (A) with an extrusion equipment to obtain a polyamide master batch (Y); and   melting and kneading 0.1 to 20 parts by mass of the polyamide master batch (Y) and 99.9 to 80 parts by mass of the polyamide (X).   
     
     
         9 . A multilayer molded article comprising:
 an outermost layer;   an innermost layer; and   a gas-barrier layer between the outermost layer and the innermost layer,   wherein the outermost layer and the innermost layer comprise a polyester resin comprising a dicarboxylic acid unit comprising 80 mol % or more of a terephthalic acid unit and a diol unit comprising 80 mol % or more of an ethylene glycol unit, and the gas-barrier layer comprises the polyamide resin composition of  claim 1 .   
     
     
         10 . The multilayer molded article of  claim 9 , which is a multilayer bottle obtained by blow-molding a multilayer preform by a hot parison method or a cold parison method. 
     
     
         11 . The polyamide resin composition of  claim 1 , wherein the polyamide (X) comprises 80 mol % or more of the metaxylylenediamine unit. 
     
     
         12 . The polyamide resin composition of  claim 3 , wherein the polyamide (X) comprises 80 mol % or more of the adipic acid unit. 
     
     
         13 . The polyamide resin composition of  claim 5 , wherein the polyamide (X) comprises 80% or more of the sebacic acid unit. 
     
     
         14 . The polyamide resin composition of  claim 1 , wherein ([COOH]—[NH 2 ]) is in a range of 20 to 70 μeq/g. 
     
     
         15 . The process of  claim 7 , wherein an amount of the alkali metal compound (C) is in a range of 0.5 to 1 in terms of a value obtained by dividing a mole number of the alkali metal compound (C) by a mole number of the phosphorus atom-comprising compound (B). 
     
     
         16 . The process of  claim 8 , wherein, in (b1), 94 to 98 parts by mass of the polyamid (X) and 6 to 2 parts by mass of the alkali compound (A) are molten and kneaded. 
     
     
         17 . The process of  claim 8 , wherein, in (b2), 1 to 5 parts by mass of the polyamid master batch (Y) and 99 to 95 parts by mass of the polyamid (X) are molten and kneaded.