To provide a resin composition capable of effectively suppressing the mechanical strength from degrading even if kept under high temperatures and high humidity, and of suppressing color transfer, as well as a molded article with use of the resin composition, and a method for producing the resin composition. The resin composition contains a polyamide resin and cerium oxide, with a lanthanum content in the resin composition of more than 0 ppm by mass and 40 ppm by mass or less.

Provided is a multilayer container including: a polyester layer containing a polyester resin (X); and a polyamide layer containing a polyamide resin (Y) and a yellowing inhibitor (A). The content of the polyamide resin (Y) is from 0.05 to 7.0 mass % relative to a total amount of all polyamide layers and all polyester layers, and the content of the yellowing inhibitor (A) is from 1 to 30 ppm relative to the total amount of all polyamide layers and all polyester layers. Also provided are a method for manufacturing the multilayer container, and a method for manufacturing a recycled polyester, the method thereof including a step of recovering polyester from the multilayer container.

Provided is a multilayer container including: a polyester layer containing a polyester resin (X); and a polyamide layer containing a polyamide resin (Y) and a yellowing inhibitor (A). The content of the polyamide resin (Y) is from 0.05 to 7.0 mass % relative to a total amount of all polyamide layers and all polyester layers, and the content of the yellowing inhibitor (A) is from 1 to 30 ppm relative to the total amount of all polyamide layers and all polyester layers. Also provided are a method for manufacturing the multilayer container, and a method for manufacturing a recycled polyester, the method thereof including a step of recovering polyester from the multilayer container.

A method produces polyamide fine particles by polymerizing a polyamide monomer (A) in the presence of a polymer (B) at a temperature equal to or higher than the crystallization temperature of a polyamide to be obtained, wherein the polyamide monomer (A) and the polymer (B) are homogeneously dissolved at the start of polymerization, and polyamide fine particles are precipitated after the polymerization. Polyamide fine particles have a number average particle size of 0.1 to 100 μm, a sphericity of 90 or more, a particle size distribution index of 3.0 or less, a linseed oil absorption of 100 mL/100 g or less, and a crystallization temperature of 150° C. or more. In particular, a polyamide having a high crystallization temperature includes fine particles having a smooth surface, a narrow particle size distribution, and high sphericity.

An anti-settling agent composition for aqueous coating materials, comprising [A] a polyamide which is obtained by polymerizing a diamine having 2-12 carbon atoms and an excess amount, relative to diamine, of either a dicarboxylic acid having 4-36 carbon atoms or a mixture of a dicarboxylic acid having 4-36 carbon atoms and a monocarboxylic acid having 2-22 carbon atoms, and [B] a hydrophobic organic compound which is a hydrocarbon modified with 1-3 hydroxyl groups and/or carboxyl groups and having 10-54 carbon atoms, and which has a freezing point of 20° C. or less or does not have a definite freezing point. The anti-settling agent is able to be easily dispersed in a coating material even if directly added into the coating material without being diluted when added into the coating material, and which imparts the coating material with excellent anti-settling properties.

An anti-settling agent composition for aqueous coating materials, comprising [A] a polyamide which is obtained by polymerizing a diamine having 2-12 carbon atoms and an excess amount, relative to diamine, of either a dicarboxylic acid having 4-36 carbon atoms or a mixture of a dicarboxylic acid having 4-36 carbon atoms and a monocarboxylic acid having 2-22 carbon atoms, and [B] a hydrophobic organic compound which is a hydrocarbon modified with 1-3 hydroxyl groups and/or carboxyl groups and having 10-54 carbon atoms, and which has a freezing point of 20° C. or less or does not have a definite freezing point. The anti-settling agent is able to be easily dispersed in a coating material even if directly added into the coating material without being diluted when added into the coating material, and which imparts the coating material with excellent anti-settling properties.

A method produces polyamide fine particles by polymerizing a polyamide monomer (A) in the presence of a polymer (B) at a temperature equal to or higher than the crystallization temperature of a polyamide to be obtained, wherein the polyamide monomer (A) and the polymer (B) are homogeneously dissolved at the start of polymerization, and polyamide fine particles are precipitated after the polymerization. Polyamide fine particles have a number average particle size of 0.1 to 100 μm, a sphericity of 90 or more, a particle size distribution index of 3.0 or less, a linseed oil absorption of 100 mL/100 g or less, and a crystallization temperature of 150° C. or more. In particular, a polyamide having a high crystallization temperature includes fine particles having a smooth surface, a narrow particle size distribution, and high sphericity.

Provided are a filament having, after a water absorption treatment, a high maintenance rate of linear strength and a high maintenance rate of knot strength, and a fishing line. The filament contains a polyamide resin (A), and the polyamide resin (A) is constituted from a constituent unit derived from a diamine and a constituent unit derived from a dicarboxylic acid, and 70 mol % or more of the constituent units derived from a diamine are derived from xylylene diamine, and 70 mol % or more of the constituent units derived from a dicarboxylic acid are derived from an α,ω-linear aliphatic dicarboxylic acid having from 11 to 14 carbons.

A retardation film includes a polyester-series resin exhibiting a negative orientation birefringence and a forward wavelength dispersibility in retardation in combination with a polyamide-series resin exhibiting a positive orientation birefringence and a flat dispersibility in retardation. The polyester-series resin may contain a constitutional unit having a fluorene-9,9-diyl group, and the polyamide-series resin may contain a constitutional unit having an alicyclic skeleton. The polyester-series resin may contain at least one constitutional unit selected from a fluorenedicarboxylic acid unit (A1) containing a unit of the formula (1) and a fluorenediol unit (B1) containing a unit of the formula (2):

##STR00001##

wherein R.sup.1 and R.sup.2 each represent a substituent; k and m each denote an integer of 0 to 8; X.sup.1a, X.sup.1b, X.sup.2a, and X.sup.2b each represent a hydrocarbon group; A.sup.1a and A.sup.1b each represent an alkylene group; n1 and n2 each denote an integer of not less than 0. The retardation film has both a high retardation expression and a reciprocal wavelength dispersibility.

It is provided that a biaxially stretched polyamide film that is excellent in oxygen gas barrier property, impact resistance, and bending fatigue resistance, which are film qualities necessary for a packaging film and that is carbon-neutral by using a raw material derived from biomass; and a laminated body using the biaxially stretched polyamide film. A biaxially stretched polyamide film in which a resin layer (layer B) mainly composed of an aliphatic polyamide resin is laminated on at least one surface of a resin layer (layer A) mainly composed of a m-xylylene group-containing-polyamide polymer, wherein the biaxially stretched polyamide film satisfies the following requirements (1) to (3): (1) the resin layer (layer A) contains not lower than 70% by mass of the m-xylylene group-containing-polyamide polymer; (2) the resin layer (layer B) mainly composed of the aliphatic polyamide resin contains at least 99 to 60% by mass of polyamide 6 and 1 to 34% by mass of a polyamide polymerized from a biomass-derived raw material; and (3) a thickness of the layer A is not lower than 10% and not higher than 30% of a total thickness of the layer A and the layer B.