Polycarbonate resin composition and molded product formed from same

Abstract

The polycarbonate resin composition of the present invention comprises: a polycarbonate ingredient including a copolymerized polycarbonate resin and an aromatic polycarbonate resin, the copolymerized polycarbonate resin having a repeating unit represented by chemical formula 1 of claim 1, a repeating unit represented by chemical formula 2 of claim 1, and a repeating unit represented by chemical formula 3 of claim 1; and an acrylic-based impact reinforcing agent. The polycarbonate resin composition has excellent scratch resistance, impact resistance, and heat resistance.

Claims

1. A polycarbonate resin composition comprising: a polycarbonate component comprising about 1 wt % to about 90 wt % of a copolymerized polycarbonate resin containing a repeat unit represented by Formula 1, a repeat unit represented by Formula 2, and a repeat unit represented by Formula 3, and about 1 wt % to about 90 wt % of an aromatic polycarbonate resin consisting of units derived from the condensation or transesterification of a carbonate precursor with a dihydric phenol compound; and an acrylic impact modifier, wherein the acrylic impact modifier is a graft copolymer in which methyl methacrylate is grafted to a rubbery polymer including at least one of a C.sub.4 to C.sub.6 diene rubber and an acrylate rubber obtained by polymerizing at least one C.sub.4 to C.sub.20 alkyl (meth)acrylate: ##STR00004## where R.sub.1 and R.sub.2 are each independently a substituted or unsubstituted C.sub.1 to C.sub.6 alkyl group, and m and n are each independently an integer from 0 to 4.

2. The polycarbonate resin composition according to claim 1, wherein, in the copolymerized polycarbonate resin, the repeat unit represented by Formula 1 is present in an amount of about 1 mol % to about 69 mol %, the repeat unit represented by Formula 2 is present in an amount of about 30 mol % to about 98 mol %, and the repeat unit represented by Formula 3 is present in an amount of about 1 mol % to about 50 mol %.

3. The polycarbonate resin composition according to claim 1, comprising the acrylic impact modifier in an amount of about 1 part by weight to about 30 parts by weight based on 100 parts by weight of the polycarbonate component.

4. The polycarbonate resin composition according to claim 1, wherein the polycarbonate resin composition has a scratch width of 312 μm or less, as measured by a ball-type scratch profile (BSP) test, and has a pencil hardness of HB or higher.

5. The polycarbonate resin composition according to claim 1, wherein the polycarbonate resin composition has an Izod impact strength of about 12 kgf.Math.cm/cm to about 90 kgf.Math.cm/cm measured on a 1/8″ thick notched Izod specimen in accordance with ASTM D256.

6. The polycarbonate resin composition according to claim 1, wherein the polycarbonate resin composition has a Vicat softening temperature (VST) of about 110° C. to about 150° C.

7. A molded article formed from the polycarbonate resin composition according to claim 1.

8. The polycarbonate resin composition according to claim 1, wherein the polycarbonate resin composition has a scratch width of 200 μm to 306 μm, as measured by a ball-type scratch profile (BSP) test.

9. The polycarbonate resin composition according to claim 1, wherein the acrylic impact modifier is a methyl methacrylate-butadiene-ethyl acrylate graft copolymer.

10. The polycarbonate resin composition according to claim 1, wherein the acrylic impact modifier is a graft copolymer in which methyl methacrylate is grafted to a rubbery polymer including an acrylate rubber.

11. The polycarbonate resin composition according to claim 1, comprising 10 wt % to 80 wt % of the copolymerized polycarbonate resin and 10 wt % to 85 wt % of the aromatic polycarbonate resin.

12. The polycarbonate resin composition according to claim 11, wherein the polycarbonate resin composition has an Izod impact strength of about 12 kgf.Math.cm/cm to about 60 kgf.Math.cm/cm measured on a 1/8″ thick notched Izod specimen in accordance with ASTM D25610 and a scratch width of about 200 μm to 306 μm, as measured by a ball-type scratch profile (BSP) test.

Description

MODE FOR INVENTION

(1) Hereinafter, the present invention will be described in more detail with reference to examples. It should be understood that these examples are provided for illustration only and are not to be construed in any way as limiting the present invention.

EXAMPLES

(2) Details of components used in the following Examples and Comparative Examples are as follows:

(3) (A) Polycarbonate Component

(4) (A1) Copolymerized Polycarbonate Resin

(5) A copolymerized polycarbonate resin prepared by the following method was used.

(6) 0.3 kg of 2,2-bis(4-hydroxyphenyl)propane (BPA), 2.70 kg of 3,3′-dimethyl bisphenol A (DMBPA), 0.28 kg of 4,4-biphenol, 2.92 kg of diphenyl carbonate, and 200 ppb of KOH (based on 1 mole of BPA) were sequentially added to a reactor, and oxygen was removed from the reactor by purging with nitrogen. The reactor was heated to and maintained at 160° C. and then heated again to 190° C., at which reaction was performed for 6 hours. Then, the reactor was heated again to 210° C. and maintained at a pressure of 100 torr for 1 hour. Next, the reactor was heated to 260° C. and maintained at a pressure of 20 torr for 1 hour, after which the pressure of the reactor was reduced to and maintained at 0.5 torr for 1 hour, thereby preparing a molten copolymerized polycarbonate resin. The prepared copolymerized polycarbonate resin was produced into pellets form using a pelletizer (weight average molecular weight: 30,000 g/mol).

(7) (A2) Aromatic Polycarbonate Resin

(8) A bisphenol-A type polycarbonate resin (L-1250WP, TEUIN Chemicals, weight average molecular weight: 25,000 g/mol) was used.

(9) (B) Impact Modifier

(10) (B1) Acrylic Impact Modifier

(11) A methyl methacrylate-butadiene-ethyl acrylate graft copolymer (EXL 2602 Grade, KUREHA CHEM Ind. Co., Ltd, mole ratio: 20:60:20) was used.

(12) (B2) Rubber-Modified Vinyl Graft Copolymer

(13) A core-shell type graft ABS copolymer having a rubber particle diameter of about 0.25 nm obtained by graft emulsion polymerization of a monomer mixture of 10.5 parts by weight of acrylonitrile and 31.5 parts by weight of styrene with 58 parts by weight of butadiene rubber was used.

(14) (C) Methacrylic Resin

(15) A polymethyl methacrylate (PMMA) resin (L84, LG MMA Corporation, weight average molecular weight: 92,000 g/mol) was used.

Examples 1 to 6 and Comparative Examples 1 to 7

(16) The above components were added in amounts as listed in Table 1, followed by melting, kneading and extrusion, thereby preparing pellets. Here, extrusion was performed using a twin-screw extruder (L/D=35) having a diameter of 45 mm, and the prepared pellets were dried at 120° C. for 4 hours, followed by injection molding using an injection machine (DHC-180MC, DONG SHIN HYDRAULIES Co., Ltd., molding temperature: 290° C., mold temperature: 60° C.).

(17) TABLE-US-00001 TABLE 1 Example Comparative Example 1 2 3 4 5 6 1 2 3 4 5 6 7 (A1) (wt %) 10 30 10 30 50 80 — — — — 10 30 80 (A2) (wt %) 85 65 80 60 40 10 80 60 40 10 80 60 10 (B1) (wt %) 5 5 10 10 10 10 10 10 10 10 — — — (B2) (wt %) — — — — — — — — — — 10 10 10 (C) (wt %) — — — — — — 10 30 50 80 — — — BSP (width, μm) 298 273 306 282 250 241 306 284 260 250 330 312 286 Pencil hardness HB F HB F H H HB F F H B B HB Heat resistance 137 131 133 128 122 117 109 105 101 98 124 119 105 (VST, ° C.) Izod impact 22.9 14.2 30.9 19.4 15.9 12.1 15.6 9.3 4.1 2.5 28.5 16.4 10.1 resistance (kgf .Math. cm/cm)

(18) Property Evaluation

(19) (1) BSP (Ball-type Scratch Profile): A 10 to 20 mm-long scratch was made on the surface of a 90 mm long×50 mm wide×2.5 mm thick specimen under a load of 1,000 g at a scratching speed of 75 mm/min using a spherical metal tip having a diameter of 0.7 mm. The profile of the scratch was subjected to surface scanning by a metal stylus tip having a diameter of 2 nm using a contact surface profiler (XP-1) manufactured by Ambios Technology Inc., thereby evaluating scratch width (unit: nm) as a measure of scratch resistance. Here, a shorter scratch width indicates a higher scratch resistance value.

(20) (2) Pencil hardness: Pencil hardness was measured under a load of 500 g according to ASTM D3362.

(21) (3) Heat resistance (VST, unit: ° C.): Heat resistance was measured under a load of 5 kgf using a Vicat softening temperature (VST) measuring instrument (6A-2, Toyoseiki Co.,Ltd.) in accordance with ASTM D1525.

(22) (4) Izod impact strength (unit: kgf.Math.cm/cm): Izod impact strength was measured on 1/8″ thick notched Izod specimens in accordance with ASTM D256.

(23) As can be seen from the results shown in Table 1, the polycarbonate resin compositions (Examples 1 to 5) according to the present invention exhibited excellent properties in terms of impact resistance, heat resistance, scratch resistance, and balance therebetween. On the contrary, the polycarbonate resin compositions prepared in Comparative Examples 1 to 4 suffered from deterioration in scratch resistance or had considerably low impact resistance and heat resistance, and exhibited unsatisfactory balance between physical properties. In addition, the polycarbonate resin compositions prepared in Comparative Examples 5 to 7 using the graft ABS copolymer had significantly reduced scratch resistance or exhibited low impact resistance and heat resistance.

(24) It should be understood that various modifications, changes, alterations, and equivalent embodiments can be made by those skilled in the art without departing from the spirit and scope of the invention.