Polyester resin composition

A polyester resin composition (C) consisting essentially of polyester resin (A), which comprises at least one of polyester resin (l) comprising a diol unit comprising 2 to 50% by mole of a diol unit having a cyclic acetal structure and a dicarboxylic acid unit having no cyclic acetal structure, polyester resin (m) comprising a dicarboxylic acid unit comprising 2 to 50% by mole of a dicarboxylic acid unit having a cyclic acetal structure and a diol unit having no cyclic acetal structure and polyester resin (n) comprising a diol unit comprising 1 to 49% by mole of a diol unit having a cyclic acetal structure and a dicarboxylic acid unit comprising 1 to 49% by mole of a dicarboxylic acid unit having a cyclic acetal structure, and polyester resin (B) having no cyclic acetal structure,

• wherein a sum of a fraction of the dicarboxylic acid unit having a cyclic acetal structure in an entire dicarboxylic acid unit and a fraction of the diol unit having a cyclic acetal structure in an entire diol unit in polyester resin composition (C) is 0.05% by mole or greater, and
• wherein the diol unit having a cyclic acetal structure is a diol unit derived from 3,9-bis(1,1-dimethyl-2-hydroxyethyl)-2,4,8,10-tetraoxaspiro[5.5]undecane or 5-methylol-5-ethyl-2-(1,1-dimethyl-2-hydroxyethyl)-1,3-dioxane.

A polyester resin composition (C) consisting essentially of polyester resin (A), which comprises at least one of polyester resin (l) comprising a diol unit comprising 2 to 50% by mole of a diol unit having a cyclic acetal structure and a dicarboxylic acid unit having no cyclic acetal structure, polyester resin (m) comprising a dicarboxylic acid unit comprising 2 to 50% by mole of a dicarboxylic acid unit having a cyclic acetal structure and a diol unit having no cyclic acetal structure and polyester resin (n) comprising a diol unit comprising 1 to 49% by mole of a diol unit having a cyclic acetal structure and a dicarboxylic acid unit comprising 1 to 49% by mole of a dicarboxylic acid unit having a cyclic acetal structure, and polyester resin (B) having no cyclic acetal structure,

• wherein a sum of a fraction of the dicarboxylic acid unit having a cyclic acetal structure in an entire dicarboxylic acid unit and a fraction of the diol unit having a cyclic acetal structure in an entire diol unit in polyester resin composition (C) is 0.05% by mole or greater, and
• wherein said polyester resin (B) is polyethylene terephthalate.

A polyester resin composition (C) consisting essentially of polyester resin (A), which comprises at least one of polyester resin (l) comprising a diol unit comprising 2 to 50% by mole of a diol unit having a cyclic acetal structure and a dicarboxylic acid unit having no cyclic acetal structure, polyester resin (m) comprising a dicarboxylic acid unit comprising 2 to 50% by mole of a dicarboxylic acid unit having a cyclic acetal structure and a diol unit having no cyclic acetal structure and polyester resin (n) comprising a diol unit comprising 1 to 49% by mole of a diol unit having a cyclic acetal structure and a dicarboxylic acid unit comprising 1 to 49% by mole of a dicarboxylic acid unit having a cyclic acetal structure, and polyester resin (B) having no cyclic acetal structure,

• wherein a sum of a fraction of the dicarboxylic acid unit having a cyclic acetal structure in an entire dicarboxylic acid unit and a fraction of the diol unit having a cyclic acetal structure in an entire diol unit in polyester resin composition (C) is 0.05% by mole or greater, and
• wherein a sum of a fraction of the dicarboxylic acid unit having a cyclic acetal structure in an entire dicarboxylic acid unit and a fraction of the diol unit having a cyclic acetal structure in an entire diol unit in polyester resin (A) is 2 to 35% by mole, polyester resin (B) is polyethylene terephthalate.

A polyester resin composition (C) consisting essentially of polyester resin (A), which comprises at least one of polyester resin (l) comprising a diol unit comprising 2 to 50% by mole of a diol unit having a cyclic acetal structure and a dicarboxylic acid unit having no cyclic acetal structure, polyester resin (m) comprising a dicarboxylic acid unit comprising 2 to 50% by mole of a dicarboxylic acid unit having a cyclic acetal structure and a diol unit having no cyclic acetal structure and polyester resin (n) comprising a diol unit comprising 1 to 49% by mole of a diol unit having a cyclic acetal structure and a dicarboxylic acid unit comprising 1 to 49% by mole of a dicarboxylic acid unit having a cyclic acetal structure, and polyester resin (B) having no cyclic acetal structure,

• wherein a sum of a fraction of the dicarboxylic acid unit having a cyclic acetal structure in an entire dicarboxylic acid unit and a fraction of the diol unit having a cyclic acetal structure in an entire diol unit in polyester resin composition (C) is 0.05% by mole or greater, and
• wherein a concentration of polyester resin (A) in polyester resin composition (C) is 40 to 95% by weight, polyester resin (B) is polybutylene terephthalate.

A polyester resin composition (C) consisting essentially of polyester resin (A), which comprises at least one of polyester resin (l) comprising a diol unit comprising 2 to 50% by mole of a diol unit having a cyclic acetal structure and a dicarboxylic acid unit having no cyclic acetal structure, polyester resin (m) comprising a dicarboxylic acid unit comprising 2 to 50% by mole of a dicarboxylic acid unit having a cyclic acetal structure and a diol unit having no cyclic acetal structure and polyester resin (n) comprising a diol unit comprising 1 to 49% by mole of a diol unit having a cyclic acetal structure and a dicarboxylic acid unit comprising 1 to 49% by mole of a dicarboxylic acid unit having a cyclic acetal structure, and polyester resin (B) having no cyclic acetal structure,

• wherein a sum of a fraction of the dicarboxylic acid unit having a cyclic acetal structure in an entire dicarboxylic acid unit and a fraction of the diol unit having a cyclic acetal structure in an entire diol unit in polyester resin composition (C) is 0.05% by mole or greater, the polyester resin composition (C) being made into a transparent sheet having entire transmittance of 87% or greater when a thickness is 1.6 mm.

A polyester resin composition (C) consisting essentially of polyester resin (A), which comprises at least one of polyester resin (l) comprising a diol unit comprising 2 to 50% by mole of a diol unit having a cyclic acetal structure and a dicarboxylic acid unit having no cyclic acetal structure, polyester resin (m) comprising a dicarboxylic acid unit comprising 2 to 50% by mole of a dicarboxylic acid unit having a cyclic acetal structure and a diol unit having no cyclic acetal structure and polyester resin (n) comprising a diol unit comprising 1 to 49% by mole of a diol unit having a cyclic acetal structure and a dicarboxylic acid unit comprising 1 to 49% by mole of a dicarboxylic acid unit having a cyclic acetal structure, and polyester resin (B) having no cyclic acetal structure,

• wherein a sum of a fraction of the dicarboxylic acid unit having a cyclic acetal structure in an entire dicarboxylic acid unit and a fraction of the diol unit having a cyclic acetal structure in an entire diol unit in polyester resin composition (C) is 0.05% by mote or greater, the polyester resin composition (C) being made into a transparent sheet having a haze value of 1% or smaller when a thickness is 0.2 mm.

A polyester resin composition (C) consisting essentially of polyester resin (A), which comprises at least one of polyester resin (l) comprising a diol unit comprising 2 to 50% by mole of a diol unit having a cyclic acetal structure and a dicarboxylic acid unit having no cyclic acetal structure, polyester resin (m) comprising a dicarboxylic acid unit comprising 2 to 50% by mole of a dicarboxylic acid unit having a cyclic acetal structure and a diol unit having no cyclic acetal structure and polyester resin (n) comprising a diol unit comprising 1 to 49% by mole of a diol unit having a cyclic acetal structure and a dicarboxylic acid unit comprising 1 to 49% by mole of a dicarboxylic acid unit having a cyclic acetal structure, and polyester resin (B) having no cyclic acetal structure, wherein a sum of a fraction of the dicarboxylic acid unit having a cyclic acetal structure in an entire dicarboxylic acid unit and a fraction of the diol unit having a cyclic acetal structure in an entire diol unit in polyester resin composition (C) is 0.05% by mole or greater, the polyester resin composition (C) being made into a film having a haze value of 5% or smaller when a thickness is 20 μm.