BIODEGRADABLE POLYESTER RESIN COMPOSITION, METHOD OF PREPARING THE SAME AND BIODEGRADABLE MOLDED ARTICLE INCLUDING BIODEGRADABLE POLYESTER RESIN COMPOSITION
An eco-friendly biodegradable polyester resin composition includes a polyester resin that includes a diol, an aromatic dicarboxylic acid and an aliphatic dicarboxylic acid, wherein a biodegradability per aliphatic carboxylic acid is 1.7 or more, the biodegradability per aliphatic carboxylic acid being a value obtained by dividing a biodegradability after 9 weeks by a ratio of the aliphatic dicarboxylic acid to the total dicarboxylic acid, and the biodegradability after 9 weeks being 85% or more.
1 . A method of preparing a biodegradable polyester resin composition, the method comprising:
esterifying a diol, an aromatic dicarboxylic acid and an aliphatic dicarboxylic acid to form a prepolymer;
polycondensing the prepolymer to form a polycondensed composition; and
reacting the polycondensed composition and a silicone-based hydrolysis agent.
2 . The method according to claim 1 , further comprising: adding a metal salt.
3 . The method according to claim 2 , wherein the metal salt comprises an iron element.
4 . The method according to claim 1 , wherein the anti-hydrolysis agent comprises a silane comprising two or more functional groups.
5 . The method according to claim 4 , wherein the anti-hydrolysis agent comprises an epoxy group or an alkoxy group.
6 . The method according to claim 1 , wherein the reacting of the polycondensed composition and the silicone-based hydrolysis agent comprises reacting the polycondensed composition and the silicone-based hydrolysis agent at about 180° C. to about 260° C. for 5 minutes to 60 minutes.
7 . The method according to claim 1 , wherein an acid value is about 2.0 mg KOH/g or less.
8 . The method according to claim 1 , wherein a hydrolysis degree after one week is about 35% to about 60%,
wherein the hydrolysis degree after the one week is a percentage reduction of a number average molecular weightmeasured after subjecting the biodegradable polyester film for about one week under high-temperature and high-humidity conditions of about and a humidity of about 100% compared to an initial number average molecular weight of the biodegradable polyester resin composition.
9 . A biodegradable polyester resin composition, comprising:
a polyester resin comprising a diol, an aromatic dicarboxylic acid and an aliphatic dicarboxylic acid;
a metal salt; and
a silicon element.
10 . The biodegradable polyester resin composition according to claim 9 , wherein the metal salt comprises an iron element, and
a mass ratio of the iron element to the silicon element is about 0.1 to about 0.7.
11 . The biodegradable polyester resin composition according to claim 10 , wherein a hydrolysis degree after one week is about 35% to about 60%,
a hydrolysis degree after about three weeks is about 85% or more, and the hydrolysis degree after one week and the hydrolysis degree after three weeks are measured using a measurement method as described below:
Measurement method
wherein the hydrolysis degree after one week is a percentage reduction of a number average molecular weight measured after subjecting the biodegradable polyester resin composition for about one week under high-temperature and high-humidity conditions of about and a humidity of about 100% compared to an initial number average molecular weight of the biodegradable polyester resin composition, and
wherein the hydrolysis degree after three weeks is a percentage reduction of a number average molecular weight measured after subjecting the biodegradable polyester resin composition for about three weeks under high-temperature and high-humidity conditions of about 80° C. and a humidity of about 100% compared to an initial number average molecular weight of the biodegradable polyester resin composition.
12 . The biodegradable polyester resin composition according to claim 10 , wherein a content of the iron element is about 1 ppm to about 100 ppm, and
a content of the silicon element is about 1 ppm to about 150 ppm.
13 . The biodegradable polyester resin composition according to claim 12 , further comprising nanocellulose,
wherein the nanocellulose comprises sulfur.
14 . The biodegradable polyester resin composition according to claim 12 , wherein a wet hardness reduction rate is about 15% or less,
wherein the wet hardness reduction rate is measured by a measurement method below:
Measurement method
wherein the biodegradable polyester resin composition is processed to produce a polyester block having a thickness of about 2.5 mm, an initial hardness of the polyester block and a wet hardness of the polyester block after immersing the polyester block for about 24 hours in water at about 30° C. are measured, and the wet hardness reduction rate is obtained by dividing a difference between the initial hardness and the wet hardness by the initial hardness.
15 . A biodegradable polyester molded article, comprising:
a polyester resin comprising a diol, an aromatic dicarboxylic acid and an aliphatic dicarboxylic acid;
a metal salt; and
a silicon element.
16 . The biodegradable polyester molded article according to claim 15 , wherein the metal salt comprises an iron element,
wherein a mass ratio of the iron element relative to the silicon element is about 0.1 to about 0.7.
17 . The biodegradable polyester molded article according to claim 16 , wherein a hydrolysis degree after one week is about 35% to about 60%,
a hydrolysis degree after about three weeks is about 85% or more, and the hydrolysis degree after one week and the hydrolysis degree after three weeks are measured by a measurement method below:
Measurement method
wherein the hydrolysis degree after one week is a percentage reduction of a number average molecular weight measured after subjecting the biodegradable polyester resin composition for about one week under high-temperature and high-humidity conditions of about and a humidity of about 100% compared to an initial number average molecular weight of the biodegradable polyester resin composition, and
wherein the hydrolysis degree after three weeks is a percentage reduction of a number average molecular weight measured after subjecting the biodegradable polyester resin composition for about three weeks under high-temperature and high-humidity conditions of about 80° C. and a humidity of about 100% compared to an initial number average molecular weight of the biodegradable polyester resin composition.
18 . The biodegradable polyester molded article according to claim 16 , wherein a content of the iron element is about 1 ppm to about 100 ppm,
a content of the silicon element is about 1 ppm to about 150 ppm.
19 . The biodegradable polyester molded article according to claim 18 , further comprising nanocellulose,
wherein the nanocellulose comprises sulfur.
20 . The biodegradable polyester molded article according to claim 15 , wherein a wet hardness reduction rate is about 15% or less,
wherein the wet hardness reduction rate is measured by a measurement method below:
Measurement method
wherein the biodegradable polyester molded article is processed to produce a polyester block having a thickness of about 2.5 mm, an initial hardness of the polyester block and a wet hardness of the polyester block after immersing the polyester block for about 24 hours in water at about 30° C. are measured, and the wet hardness reduction rate is obtained by dividing a difference between the initial hardness and the wet hardness by the initial hardness.