Abstract: There is provided a production method of a crystalline polyamide resin by thermal polycondensation of a mixture including at least a diamine component, a dicarboxylic acid component and water as a starting material, wherein the diamine component includes (A) pentamethylene diamine at a ratio that is equal to or greater than 10 mol % and less than 80 mol % relative to a gross amount of the diamine component; and the dicarboxylic acid component includes (B) at least one selected from the group consisting of an aromatic dicarboxylic acid, an alicyclic dicarboxylic acid and dialkyl ester derivatives thereof at a ratio that is equal to or greater than 76 mol % and equal to or less than 100 mol % relative to a gross amount of the dicarboxylic acid component.

Abstract: Provided are a polyester polymerization catalyst with which the generation of foreign materials caused by the catalyst or mold pollution at the time of molding are reduced and polyesters having remarkably superior thermal stability and color tone can be obtained. Provided is a polyester polymerization catalyst produced by the reaction of a titanium compound and a mannitol in a molar ratio of titanium atom to mannitol of from 1:1 to 1:3. A method for producing a polyester employs the polyester polymerization catalyst.

Abstract: There is provided a production method of a crystalline polyamide resin by thermal polycondensation of a mixture including at least a diamine component, a dicarboxylic acid component and water as a starting material, wherein the diamine component includes (A) pentamethylene diamine at a ratio that is equal to or greater than 10 mol % and less than 80 mol % relative to a gross amount of the diamine component; and the dicarboxylic acid component includes (B) at least one selected from the group consisting of an aromatic dicarboxylic acid, an alicyclic dicarboxylic acid and dialkyl ester derivatives thereof at a ratio that is equal to or greater than 76 mol % and equal to or less than 100 mol % relative to a gross amount of the dicarboxylic acid component, the production method comprising: a first step that heats the above mixture, which has a water content equal to or less than 30% by weight, at a temperature equal to or higher than 200° C. under a pressure of 1.8 to 3.

Abstract: Provided are a polyester polymerization catalyst with which the generation of foreign materials caused by the catalyst or mold pollution at the time of molding are reduced and polyesters having remarkably superior thermal stability and color tone can be obtained. Provided is a polyester polymerization catalyst produced by the reaction of a titanium compound and a mannitol in a molar ratio of titanium atom to mannitol of from 1:1 to 1:3. A method for producing a polyester employs the polyester polymerization catalyst.