Polyamide-10 having superior mechanical and thermal properties and method for preparation thereof

Abstract

This invention relates to polyamide-10 and a method for preparing the same, and according to this invention, polyamide-10 having superior mechanical and thermal properties can be prepared by preparing polyamide-10 while controlling the condensation polymerization conditions of 10-aminodecanoic acid.

Claims

1. Polyamide-10, wherein number average molecular weight (g/mol) is 5000 to 25000, tensile strength (MPa) and tensile modulus (MPa), measured according to ISO 527-2, are 50 to 60, and 800 to 1400, respectively, and flexural strength (MPa) and flexural modulus (MPa), measured according to ISO 178, are 50 to 90, and 1200 to 1900, respectively.

2. The polyamide-10 according to claim 1, wherein tensile modulus (MPa) is 1000 to 1200.

3. The polyamide-10 according to claim 1, wherein the flexural strength (MPa) is 60 to 80.

4. The polyamide-10 according to claim 1, wherein the flexural modulus (MPa) is 1300 to 1800.

5. The polyamide-10 according to claim 1, wherein heat deflection temperature measured according to ISO 75 (0.45 MPa condition) is 100 C. or more.

6. The polyamide-10 according to claim 1, wherein Rockwell hardness measured according to ISO 2039 is 90 or more.

7. A method for preparing the polyamide-10 according to claim 1, comprising steps of: adding 10-aminodecanoic acid in a reactor (step 1); raising the temperature of the reactor to 230 to 250 C., and then, maintaining the temperature while stirring 10-aminodecanoic acid (step 2); reducing the pressure in the reactor to 10 torr or less (step 3); subjecting the 10-aminodecanoic acid to a condensation polymerization reaction, and then, raising the pressure in the reactor to normal pressure (step 4); and recovering a product from the reactor (step 5).

8. The method according to claim 7, wherein in the step 2, after completing the temperature rise, the temperature is maintained for 1 hour to 4 hours.

9. The method according to claim 7, wherein the step 3 is conducted by sequentially reducing pressure by 50 to 200 torr in plural stages, to reduce pressure to 10 torr or less.

10. The method according to claim 9, wherein the plural stages include 2 to 10 stages.

11. The method according to claim 9, wherein each of the pressure reduction stages is sequentially progressed at an interval of 2 to 10 minutes.

12. The method according to claim 7, wherein the condensation polymerization reaction of step 4 is conducted for 10 to 60 minutes.

13. The method according to claim 7, wherein after the step 4, normal pressure is maintained for 5 to 20 minutes.

Description

DETAILED DESCRIPTION OF THE EMBODIMENTS

(1) Hereinafter, preferable examples are presented for better understanding of the invention, but the following examples are presented only as the illustrations of the invention and the scope of the invention is not limited thereby.

Example 1

(2) 2.5 kg of 10-aminodecanoic acid (10-ADA) was introduced into a reactor with a capacity of 5 kg. The reactor is equipped with a stirring axis connected to a stirring motor and a helical blade, and has a nitrogen gas inlet, a vacuum vent, and a reaction product outlet.

(3) A process of reducing the pressure inside of the reactor to 200 torr using a vacuum pump, and then, introducing nitrogen to control to a normal pressure was repeated three times, thus removing air existing in the reactor. After finally introducing nitrogen, nitrogen gas was supplied at 1000 cc per minute using a gas flowmeter, and the vent was opened to maintain a nitrogen atmosphere in the reactor.

(4) The temperature of the reactor was raised to 240 C. During the temperature rise process, if a temperature reached 190 C., a stirrer was operated to begin stirring at 10 rpm, and if reached 220 C., stirring at 30 rpm, and if reached 240 C., stirring at 65 rpm, and the stirring speed was maintained.

(5) After 2 hours, a vacuum pump was operated to gradually reduce pressure to 700 torr, 600 torr, 400 torr, 150 torr, 100 torr, 50 torr, and 5 torr or less (total 7 steps). Wherein, each pressure reduction step was conducted at an interval of 5 minutes.

(6) While maintaining 5 torr or less, a reaction was progressed for 1 hour, and torque meter was observed and if reached to 2.5 V, stirring and heating were stopped to terminate polymerization.

(7) Nitrogen was introduced in the reactor and discarded at normal pressure, and after leaving for 10 minutes, outlet in the lower part of the reactor was opened. Polyamide-10 strands discharged through the outlet were passed through a cold water tank, and pellets were obtained with a pelletized, and then, dried to finally obtain polyamide-10.

Example 2

(8) Polyamide-10 was obtained by the same method as Example 1.

(9) Comparative Examples 1 and 2

(10) The following polyamides were used as Comparative Examples 1 and 2. Comparative Example 1: PA11 (Rilsan, BESNO TL) Comparative Example 2: PA12 (Rilsan, AESNO TL)

(11) Experimental Example

(12) For the polyamide-10 prepared in Examples 1 and 2, and the polyamide of Comparative Examples 1 and 2, each property was evaluated.

(13) 1) Number average molecular weight: A sample was dissolved in hexafluoroisopropanol(HFIP)/0.01 N sodium trifluoroacetate solvent, and number average molecular weight was measured using GPC(Viscotek corporation TDA 305, Refractive index detector), using GPC column (Agilent, PLgel Mixed D).

(14) 2) Tensile strength and tensile elongation: measured according to ISO 527-2.

(15) 3) Tensile strength and elongation at break: measured according to ISO 527-2.

(16) 4) Tensile modulus: measured according to ISO 527-2.

(17) 5) Flexural strength and flexural modulus: measured according to ISO 178.

(18) 6) Impact strength: measured according to ISO 179.

(19) 7) Heat deflection temperature (HDT): measured according to ISO 75.

(20) 8) Hardness (Rockwell R): measured according to ISO 2039.

(21) The results evaluated by the above methods were shown in the following Table 1.

(22) TABLE-US-00001 TABLE 1 Comparative Comparative Unit Example 1 Example 2 Example 1 Example 2 Specific gravity 1.03 1.03 1.02 1.01 Melting point C. 186 185 189 177 Number average g/mol 13,548 13,770 11,143 14,227 molecular weight Tensile strength MPa 54 52 40 45 Tensile elongation % 7 7 8 7 Tensile strength at MPa 57 53 52 47 break Elongation at break % 403 312 415 338 Tensile modulus MPa 1,163 1,117 780 959 Flexural strength MPa 73 69 48 56 Flexural modulus MPa 1,788 1,772 1,121 1,312 Impact strength KJ/m.sup.2 6 6 6 11 (Charpy, Notched, 23 C.) Impact strength KJ/m.sup.2 5 5 6 5 (Charpy, Notched, 30 C.) HDT (0.45 MPa) C. 110 112 107 103 HDT (1.85 MPa) C. 53 54 48 53 Hardness 107 106 98 102 (Rockwell R)