Polyamide resin, preparation method therefor, and molded product including same
The polyamide resin of the present invention is a polyamide resin containing an amine group and a carboxyl group, wherein the amine group concentration is about 200 to 300 μeq/g and two to six times as high as the carboxyl group concentration. The polyamide resin has excellent long-thermal stability.
1. A polyamide resin containing an amine group and a carboxyl group,
wherein the amine group is present at a concentration of about 200 to about 300 μeq/g, and
the concentration of the amine group is about 2 to about 6 times the concentration of the carboxyl group, and
tensile strength maintenance rate of the polyamide resin evaluated by compounding 35 parts by weight of a glass fiber (GF) with respect to 100 parts by weight of the polyamide resin is 45% or more.
2. The polyamide resin of claim 1 , wherein the polyamide resin is obtained by polymerizing (A) a dicarboxylic acid component comprising (a1) an aromatic dicarboxylic acid and (B) a diamine component comprising (b1) an aliphatic diamine.
3. The polyamide resin of claim 2 , wherein the aromatic dicarboxylic acid (a1) comprises at least one of aromatic dicarboxylic acids having 8 to 20 carbon atoms.
4. The polyamide resin of claim 2 , wherein the aliphatic diamine (b1) comprises at least one of aliphatic diamines having 4 to 20 carbon atoms.
5. The polyamide resin of claim 2 , wherein the dicarboxylic acid component (A) further comprises (a2) an amine group-containing dicarboxylic acid.
6. The polyamide resin of claim 5 , wherein the amine group-containing dicarboxylic acid (a2) is represented by the following Formula 1:
wherein R 1 is a hydrogen atom, or a hydrocarbon group having 1 to 10 carbon atoms, and R 2 is a linear, branched or cyclic hydrocarbon group having 1 to 20 carbon atoms, unsubstituted or substituted with a substituent selected from the group consisting of a C 1 -C 10 alkyl group, C 6 -C 18 aryl group, halogen, and a combination thereof.
7. The polyamide resin of claim 5 , wherein the dicarboxylic acid component (A) includes the amine group-containing dicarboxylic acid (a2) in an amount of about 0.1 to about 30 mol %, based on the total amount of the dicarboxylic acid component (A).
8. The polyamide resin of claim 1 , wherein the polyamide resin has an end group capped with an end capping agent comprising at least one of an aliphatic carboxylic acid and/or an aromatic carboxylic acid.
9. The polyamide resin of claim 1 , wherein the polyamide resin has an intrinsic viscosity of about 0.6 to about 1.5 dL/g, as measured in a 25° C. sulfuric acid solution using an Ubbelohde viscometer.
10. The polyamide resin of claim 1 , wherein the polyamide resin has a glass transition temperature (Tg) of about 120° C. or higher.
11. The polyamide resin of claim 1 , wherein the polyamide resin has a melting temperature (Tm) of about 280 to about 320° C., and a crystallization temperature (Tc) of about 260 to about 280° C.
12. A molded article comprising the polyamide resin defined in claim 1 .
13. A method for preparing a polyamide resin, comprising:
polymerizing (A) a dicarboxylic acid component comprising (a1) an aromatic dicarboxylic acid and (B) a diamine component comprising (b1) an aliphatic diamine so that an amine group in the resin is present at a concentration of about 200 to about 300 μeq/g, and the concentration of the amine group is about 2 to about 6 times the concentration of a carboxyl group,
wherein tensile strength maintenance rate of the polyamide resin evaluated by compounding 35 parts by weight of a glass fiber (GF) with respect to 100 parts by weight of the polyamide resin is 45% or more.
14. The method of claim 13 , wherein the dicarboxylic acid component (A) further comprises (a2) an amine group-containing dicarboxylic acid in an amount of about 0.1 to about 30 mol %, based on the total amount of the dicarboxylic acid component (A).