Biodegradable molded article and biodegradable polyester resin composition

A biodegradable polyester resin composition, comprising:

• a polyester resin comprising a diol, an aromatic dicarboxylic acid and an aliphatic dicarboxylic acid,
• wherein, when continuously irradiated with ultraviolet rays from a UVA 340 ultraviolet light lamp at an intensity of 0.75 W/m2, a tensile strength decrease rate from a beginning of the ultraviolet irradiation to 1 day ranges from 5% to 40%,
• wherein the tensile strength decrease rate is measured by the method below:
• in the measurement method, the biodegradable polyester resin composition is dried at 80° C., placed in a stainless steel mold, and compressed at 210° C. under a pressure of 10 MPa for 3 minutes to produce a polyester sheet having a thickness of 300 μm, and the tensile strength decrease rate is obtained by dividing a difference between an initial tensile strength of the polyester sheet and a tensile strength after ultraviolet irradiation of the polyester sheet by the initial tensile strength,
• wherein an alternating ratio of the polyester resin ranges from 0.37 to 0.59,
• wherein the alternating ratio is a ratio of a diol quantity, bonded between the aromatic dicarboxylic acid and the aliphatic dicarboxylic acid, to a total quantity of diols in the polyester resin,
• wherein the polyester resin include the following bonding structures:
• Aromatic dicarboxylic acid-diol-aliphatic dicarboxylic acid- [Bonding Structure 1]
• Aromatic dicarboxylic acid-diol-aromatic dicarboxylic acid- [Bonding Structure 2]
• Aliphatic dicarboxylic acid-diol-aliphatic dicarboxylic acid-, [Bonding Structure 3]
• wherein the alternating ratio is calculated according to Equation 1 below:
• Alternating
• ⁢
• ratio
• =
• DM
• ⁢
• 1
• DM
• ⁢
• 1
• +
• DM
• ⁢
• 2
• +
• DM
• ⁢
• 3
• [
• Equation
• ⁢
• 1
• ]
• where DM1 is a molar ratio of a diol included in Bonding Structure 1, DM2 is a molar ratio of a diol included in Bonding Structure 2, and DM3 is a molar ratio of a diol included in Bonding Structure 3,
• wherein the initial tensile strength ranges from 40 MPa to 60 MPa, and a tensile strength after 7 days ranges from 1 MPa to 15 MPa,
• wherein the biodegradable molded article comprises a crystallinity regulator,
• wherein the crystallinity regulator comprises diisopropyl adipate,
• wherein the crystallinity regulator further comprises tetrahydrofuran.

A biodegradable polyester resin composition, comprising:

• a polyester resin comprising a diol, an aromatic dicarboxylic acid and an aliphatic dicarboxylic acid;
• and
• a crystallinity regulator,
• wherein the biodegradable polyester resin composition has a crystallinity ranging from 10% to 15%,
• wherein an alternating ratio of the polyester resin ranges from 0.37 to 0.59,
• wherein the alternating ratio is a ratio of a diol quantity, bonded between the aromatic dicarboxylic acid and the aliphatic dicarboxylic acid, to a total quantity of diols in the polyester resin,
• wherein the polyester resin include the following bonding structures:
• Aromatic dicarboxylic acid-diol-aliphatic dicarboxylic acid- [Bonding Structure 1]
• Aromatic dicarboxylic acid-diol-aromatic dicarboxylic acid- [Bonding Structure 2]
• Aliphatic dicarboxylic acid-diol-aliphatic dicarboxylic acid-, [Bonding Structure 3]
• wherein the alternating ratio is calculated according to Equation 1 below:
• Alternating
• ⁢
• ratio
• =
• DM
• ⁢
• 1
• DM
• ⁢
• 1
• +
• DM
• ⁢
• 2
• +
• DM
• ⁢
• 3
• [
• Equation
• ⁢
• 1
• ]
• where DM1 is a molar ratio of a diol included in Bonding Structure 1, DM2 is a molar ratio of a diol included in Bonding Structure 2, and DM3 is a molar ratio of a diol included in Bonding Structure 3,
• wherein the crystallinity regulator comprises diisopropyl adipate,
• wherein the crystallinity regulator further comprises tetrahydrofuran.