Polyacetal resin composition and method for producing the same

Abstract

The purpose of the present invention is to provide: a polyacetal resin composition which is excellent in terms of impact resistance, thermal stability, and releasability; and a process for producing the polyacetal resin composition. The polyacetal resin composition comprises 100 parts by mass of a polyacetal resin (A) in which the molecular chain has neither a crosslink nor a branch therein, 0.01-10.0 parts by mass of an antioxidant (B), 0.01-5.0 parts by mass of a nitrogenous compound (C), and 0.05-1.0 parts by mass of a fatty acid amide (D), and has a melt index, as measured in accordance with ISO 1133, of 0.5-1.5 g/10 min. A process for producing the polyacetal resin compositions is also provided.

1 . A polyacetal resin composition comprising 100 parts by mass of a polyacetal resin (A) having a molecular chain with neither crosslinks nor branches, 0.01 to 10.0 parts by mass of an antioxidant (B), 0.01 to 5.0 parts by mass of a nitrogen-containing compound (C) and 0.05 to 1.0 part by mass of a fatty acid amide (D), wherein the polyacetal resin composition has a melt index of 0.5 to 1.5 g/10 minutes as measured in accordance with ISO 1133. 
     
     
         2 . The polyacetal resin composition according to  claim 1 , which has a Charpy impact value of not less than 10 kJ as measured in accordance with ISO 194. 
     
     
         3 . The polyacetal resin composition according to  claim 1 , wherein the antioxidant (B) is a hindered phenol-based antioxidant. 
     
     
         4 . The polyacetal resin composition according to  claim 1 , wherein the antioxidant (B) is triethylene glycol-bis-3-(3-t-butyl-4-hydroxy-5-methylphenyl) propionate. 
     
     
         5 . The polyacetal resin composition according to  claim 1 , wherein the nitrogen-containing compound (C) is an amino-substituted triazine compound. 
     
     
         6 . The polyacetal resin composition according to  claim 1 , wherein the nitrogen-containing compound (C) is melamine. 
     
     
         7 . The polyacetal resin composition according to  claim 1 , wherein the fatty acid amide (D) is hexamethylenebisstearamide or ethylenebisstearamide. 
     
     
         8 . The polyacetal resin composition according to  claim 1 , wherein the fatty acid amide (D) is ethylenebisstearamide. 
     
     
         9 . A method for producing a polyacetal resin composition according to  claim 1 , comprising melt kneading 100 parts by mass of a polyacetal resin (A) having a molecular chain with neither crosslinks nor branches, 0.01 to 10.0 parts by mass of an antioxidant (B), 0.01 to 5.0 parts by mass of a nitrogen-containing compound (C) and 0.05 to 1.0 part by mass of a fatty acid amide (D) at a temperature controlled within the range of not less than 250° C. and not more than 270° C. 
     
     
         10 . The production method according to  claim 9 , wherein the melt kneading is performed for not less than 1 minute and not more than 5 minutes. 
     
     
         11 . A molded body comprising the polyacetal resin composition according to  claim 1 . 
     
     
         12 . A part, which is a cut molded body according to  claim 11 . 
     
     
         13 . The polyacetal resin composition according to  claim 2 , wherein the antioxidant (B) is a hindered phenol-based antioxidant. 
     
     
         14 . The polyacetal resin composition according to  claim 2 , wherein the antioxidant (B) is triethylene glycol-bis-3-(3-t-butyl-4-hydroxy-5-methylphenyl) propionate. 
     
     
         15 . The polyacetal resin composition according to  claim 2 , wherein the nitrogen-containing compound (C) is an amino-substituted triazine compound. 
     
     
         16 . The polyacetal resin composition according to  claim 2 , wherein the nitrogen-containing compound (C) is melamine. 
     
     
         17 . The polyacetal resin composition according to  claim 2 , wherein the fatty acid amide (D) is hexamethylenebisstearamide or ethylenebisstearamide. 
     
     
         18 . The polyacetal resin composition according to  claim 2 , wherein the fatty acid amide (D) is ethylenebisstearamide. 
     
     
         19 . A molded body comprising the polyacetal resin composition according to  claim 2 . 
     
     
         20 . The polyacetal resin composition according to  claim 3 , wherein the antioxidant (B) is triethylene glycol-bis-3-(3-t-butyl-4-hydroxy-5-methylphenyl) propionate.