POLYBUTYLENE TEREPHTHALATE RESIN COMPOSITION HAVING EXCELLENT FLAME RETARDANCY AND HYDROLYSIS RESISTANCE AND MOLDED ARTICLE PRODUCED THEREFROM

Abstract

The present invention relates to a polybutylene terephthalate resin composition having excellent flame retardancy and hydrolysis resistance and a molded article produced therefrom and, more specifically, to a polybutylene terephthalate resin composition and a molded article produced therefrom, the polybutylene terephthalate resin composition having hydrolysis resistance and heat resistance that are improved by melt-processing a polybutylene terephthalate resin by using polycyclohexylenedimethylene terephthalate resin, and simultaneously having flame retardancy and impact resistance that are improved by using a phosphorus-based flame retardant and a compatibilizer.

Claims

1. A polybutylene terephthalate resin composition comprising: (1) 40 to 70 parts by weight of polybutylene terephthalate resin; (2) 10 to 40 parts by weight of polycyclohexylenedimethylene terephthalate resin; (3) 12 to 25 parts by weight of a phosphorus-based flame retardant; (4) 0.1 to 3 parts by weight of a flame retardant supplement; and (5) 0.1 to 2 parts by weight of a compatibilizer, based on 100 parts by weight of the total composition.

2. The polybutylene terephthalate resin composition according to claim 1, wherein the polybutylene terephthalate resin has an intrinsic viscosity of 0.7 to 1.5 dl/g.

3. The polybutylene terephthalate resin composition according to claim 1, wherein the polycyclohexylenedimethylene terephthalate resin has a melting point of 280° C. or higher and an intrinsic viscosity of 0.6 to 0.9 dl/g.

4. The polybutylene terephthalate resin composition according to claim 1, wherein the phosphorus-based flame retardant is a phosphoric acid ester compound represented by the following Formula (1): ##STR00003## in Formula 1, each of R.sub.1, R.sub.2, R.sub.3 and R.sub.4 is independently C.sub.1-C.sub.8 alkyl, C.sub.5-C.sub.6 cycloalkyl, C.sub.6-C.sub.20 aryl or C.sub.7-C.sub.20 aralkyl; n is independently 0 or 1, N is 0 to 10, X is a C.sub.6-C.sub.30 mononuclear aromatic or polynuclear aromatic group.

5. The polybutylene terephthalate resin composition according to claim 1, wherein the flame retardant supplement is at least one compound selected from the group consisting of melamine cyanurate, melamine phosphate, melamine polyphosphate and melamine pyrophosphate.

6. The polybutylene terephthalate resin composition according to claim 1, wherein the compatibilizer is a styrene-glycidyl methacrylate random copolymer.

7. The polybutylene terephthalate resin composition according to claim 1, further comprising at least one additive selected from the group consisting of a releasing agent, a heat stabilizer, an antioxidant, a lubricant, a pigment, a light stabilizer and a black master batch.

8. A molded article prepared from the polybutylene terephthalate resin composition according to claim 1.

Description

EXAMPLES

[0051] Components Used in Examples and Comparative Examples

[0052] (A) Polybutylene terephthalate (PBT): polybutylene terephthalate having an intrinsic viscosity (IV) of 0.8 to 1.1 dl/g

[0053] (B) polycyclohexylenedimethylene terephthalate (PCT): polycyclohexylenedimethylene terephthalate having a melting point of 280° C. or higher and an intrinsic viscosity of 0.75 dl/g (manufacturer: SKC, SKYPURA 3502)

[0054] (C) Phosphorus-based flame retardant: metal phosphinate (manufacturer: Clariant, Exolit OP1240)

[0055] (D) Flame retardant supplement: melamine polyphosphate (manufacturer: BASF, Melapur 200)

[0056] (E) Compatibilizer: copolymer of styrene and glycidyl methacrylate (manufacturer: AddiCo, Addico 9302)

Examples 1 to 3 and Comparative Examples 1 to 6

[0057] According to the compositions and contents of Table 1 below, the components were mixed with a tumbler mixer for 10 minutes, added to a twin screw-type extruder and melted and extruded at a cylinder temperature of 250° C. and a stirring speed of 250 rpm to prepare pellets. The prepared pellets were dried at 80° C. for 4 hours or more, and then injected in an injection machine at 250° C. (manufacturer: LG Cable & System Ltd., product name: LGH-200N) to prepare specimens. The physical properties of the prepared specimens were evaluated by the following method, and the results are shown in Table 1 below.

[0058] <Method of Measuring Physical Properties>

[0059] (1) IZOD impact strength (unit: kgf cm/cm): Based on the evaluation method specified in ASTM D256, a notch was made in ⅛″ thick Izod specimen and evaluated.

[0060] (2) Tensile strength (unit: kgf/cm.sup.2): It was measured under the conditions of 50 mm/min according to the evaluation method specified in ASTM D638.

[0061] (3) Flexural strength and flexural modulus (unit: kgf/cm.sup.2): It was measured under the condition of 2.8 mm/min according to the evaluation method specified in ASTM D790.

[0062] (4) Flame retardancy: It was measured by the UL94 V test method using a specimen having a thickness of 0.8 mm.

[0063] (5) Hydrolysis resistance: Distilled water was put in a PCT (Pressure Cook Test) equipment capable of being pressurized, and treated for 144 hours while maintaining 120° C., 2 atm and 100% RH. After the test, the degree of deterioration of the physical properties compared to the initial physical properties was calculated. (⊚: very good, Δ: average, X: poor).

TABLE-US-00001 TABLE 1 Examples Comparative Examples 1 2 3 1 2 3 4 5 6 Composition (A) 56 58.1 48 99 80 72 61.6 56.7 54.6 (parts by (B) 24 24.9 32 — — 8 26.4 24.3 23.4 weight) (C) 18 15 18 — 18 18 10 18 18 (D) 1 1 1 — 1 1 1 1 1 (E) 1 1 1 1 1 1 1 — 3 Properties Impact Before 2.44 2.53 2.40 4.2 2.65 2.13 2.58 2.38 2.45 strength PCT After 1.95 2.01 2.03 1.42 1.17 1.46 2.11 1.82 1.96 PCT Tensile Before 454 470 435 555 345 352 466 447 458 strength PCT After 421 437 403 406 255 278 433 389 423 PCT Flexural strength 554 589 544 753 519 535 542 551 560 Flexural modulus 22263 23137 21180 20630 21237 22044 22089 22232 22359 Flame retardancy V-0 V-1 V-0 HB V-0 V-0 HB V-0 V-0 (UL94, 1.5 mm) Hydrolysis ⊚ ⊚ ⊚ X X Δ ⊚ ⊚ ⊚ resistance

[0064] As shown in Table 1 above, the polybutylene terephthalate resin compositions of Examples 1 to 3 according to the present invention have excellent mechanical properties, and significantly less deterioration in mechanical properties after flame retardancy and heat- and moisture-resistance tests. Therefore, it can be seen that they can be particularly suitably used for the manufacturing of electronic components.

[0065] On the other hand, the compositions of the Comparative Examples were inferior to at least one of the above evaluation items. It can be seen that in Comparative Examples 1 and 2, in which the polycyclohexylenedimethylene terephthalate resin and the phosphorus-based flame retardant are not included, the flame retardancy and hydrolysis resistance are poor. In Comparative Example 3, in which polycyclohexylenedimethylene terephthalate was not sufficiently included, physical properties were deteriorated due to hydrolysis after the heat- and moisture-resistance tests, and Comparative Example 4 in which the phosphorus-based flame retardant was not sufficiently comprised showed a decrease in flame retardancy. It can be seen that in Comparative Example 5 in which the compatibilizer is not comprised, the physical property retention after the heat- and moisture-resistance tests is lowered compared to Example 1, and it can be seen that in Comparative Example 6 in which the compatibilizer is introduced in an excessive amount, there is no additional effect on improving the physical property retention after the heat- and moisture-resistance tests.