Ultra-high flow styrene acrylonitrile copolymer compositions

Abstract

Thermoplastic molding composition comprising (A) 40 to 80 wt.-% SAN copolymer (S/AN-ratio 78:22 to 65:35, Mw 80,000 to 250,000 g/mol); (B) 20 to 60 wt.-% SBC block copolymer (monovinylarene 61 to 64 wt.-%) comprising conjugated diene/monovinylarene tapered polymer blocks; and (C) 0 to 5 wt.-% additives and/or processing aids (C); exhibiting ultra-high melt flow with good mechanical, thermal and optical properties, a process for its preparation and its use for the production of bulky and/or thin walled articles.

Claims

1. A thermoplastic molding composition comprising components A, B, and C: (A) 40 to 80 wt.-% of at least one copolymer (A) of styrene and acrylonitrile in a weight ratio of from 78:22 to 65:35, wherein the styrene and/or acrylonitrile is optionally partially replaced by methyl methacrylate, maleic anhydride, N-phenylmaleimide, and/or 4-phenylstyrene; wherein copolymer (A) has a weight average molar mass M.sub.w of 80,000 to 150,000 g/mol; (B) 20 to 60 wt.-% of at least one coupled conjugated diene/monovinylarene block copolymer (B) comprising at least three consecutive conjugated diene/monovinylarene tapered polymer blocks, wherein in the final block copolymer all conjugated diene is incorporated into the tapered polymer block, and, based on the total weight of the final block copolymer, the monovinylarene is present in an amount of 61 to 64 wt.-%, and the conjugated diene is present in an amount of 36 to 39 wt.-%; and (C) 0 to 5 wt.-% additives and/or processing aids (C); wherein the components A, B, and, if present, C, sum to 100 wt.-%.

2. The thermoplastic molding composition according to claim 1, comprising: 55 to 70 wt.-% component (A), 30 to 45 wt.-% component (B), and 0 to 5 wt.-% component (C).

3. The thermoplastic molding composition according to claim 1, wherein copolymer (A) is a copolymer of styrene and acrylonitrile in a weight ratio of from 75:25 to 70:30.

4. The thermoplastic molding composition according to claim 1, wherein M.sub.w of copolymer (A) is 90,000 to 150,000 g/mol.

5. The thermoplastic molding composition according to claim 1, wherein in block copolymer (B) the conjugated diene is 1,3-butadiene and the monovinylarene is styrene.

6. The thermoplastic molding composition according to claim 1, wherein in each individual tapered polymer block of block copolymer (B) the monovinylarene is present in an amount of from 2 to 18 wt.-%, based on the total weight of the final block copolymer, and the conjugated diene is present in an amount of from 8 to 17 wt.-%, based on the total weight of the final block copolymer.

7. The thermoplastic molding composition according to claim 1, where the block copolymer (B) comprises at least one polymer chain S1-S2-B1/S3-B2/S4-B3/S5˜, wherein S1 and S2 are monovinylarene blocks, blocks B1/S3, B2/S4, B3/S5 are tapered blocks containing a mixture of monovinylarene and conjugated diene, and ˜ is the bond to the coupling agent.

8. The thermoplastic molding composition according to claim 1, wherein in each tapered polymer block of block copolymer (B) the conjugated diene is present in an amount of from 0.6 parts to 4 parts per part monovinylarene in the tapered polymer block.

9. A process for the preparation of the thermoplastic molding composition according to claim 1 by melt mixing the components (A), (B), and, if present, (C), at temperatures in the range of from 180° C. to 250° C.

10. A method of using the thermoplastic molding composition according to claim 1 to produce a shaped article.

11. A shaped article made from the thermoplastic molding composition according to claim 1.

12. A washing machine lid made from the thermoplastic molding composition according to claim 1.

13. A pen made from the thermoplastic molding composition according to claim 1.

Description

EXAMPLES

(1) Test Methods

(2) Molar Mass M.sub.w

(3) The weight average molar mass M.sub.w is determined by GPC (solvent: tetrahydrofuran, polystyrene as polymer standard) with UV detection according to DIN 55672-1:2016-03.

(4) Melt Flow Index (MFI) or Melt Volume Flow Rate (MFR)

(5) MFI/MFR tests of the blends were performed according to ISO 1133 standard at 220° C./10 kg load and at 200° C./5 kg load by use of a MFI-machine of CEAST, Italy.

(6) Izod Impact Test

(7) Izod impact tests were performed on notched specimens of the blends (ISO 180) using an instrument of CEAST, Italy.

(8) Tensile Strength (TS) and Tensile Modulus (TM) Test

(9) Tensile tests (ISO 527) of the blends were carried out at 23° C. using an Universal testing Machine (UTM) of Instron, UK.

(10) Flexural Strength (FS) and Flexural Modulus (FM) Test

(11) Flexural test of the blends (ISO 178) was carried out at 23° C. using a UTM of Lloyd Instruments, UK.

(12) VICAT Softening Temperature (VST)

(13) Vicat softening temperature test was performed on injection molded test specimen (ISO 306) using a Zwick Roell GmbH machine. The test was carried out at a heating rate of 120° C./hr at 50 N loads (Method B) and and carried out at a heating rate of 50° C./hr at 10 N loads (Method A).

(14) Transparency

(15) The transparency (%) is checked by ASTM D 1003 using Datacolor 850 US machine.

(16) Haze

(17) The % haze (%) is checked by ASTM D 1003 using Datacolor 850 US machine.

(18) Materials Used:

(19) Component A

(20) Statistical copolymer (A-I) from styrene and acrylonitrile with a ratio of polymerized styrene to acrylonitrile of 73:27 with a weight average molecular weight Mw of 100,000 g/mol and a melt volume flow rate (MVR) (220° C./10 kg load) of 75 g/10 minutes, produced by free radical solution polymerization.

(21) Component B

(22) B-1: K-resin® KR20, a styrene butadiene block copolymer (styrene content 62 wt.-%) from Ineos Styrolution, Germany.

(23) B-2: K-resin® KRDEV034A, a styrene butadiene block copolymer (styrene content 62 wt.-%) from Ineos Styrolution, Germany.

(24) Thermoplastic Molding Compositions

(25) SAN-copolymer (A-I), SBC-block copolymer (B-1) or (B-2), and the afore-mentioned components (C) were mixed (composition see Tables 1 and 2, batch size 5 kg) for 2 minutes in a high speed mixer to obtain good dispersion and a uniform premix and then said premix was melt blended in a twin-screw extruder at a speed of 80 rpm and using an incremental temperature profile from 190 to 220° C. for the different barrel zones. The extruded strands were cooled in a water bath, air-dried and pelletized.

(26) Standard test specimens of the obtained blend were injection molded at a temperature of 190 to 230° C. and test specimens were prepared for mechanical testing. The test results (properties) are presented in Tables 3 and 4.

(27) TABLE-US-00001 TABLE 1 Composition (in wt.- %) of Tested Blends Composition Component  1*  2*  3*  4  5  6  7* B-2 100 80 70 60 40 20  0 A-1  0 20 30 40 60 80 100 *non-inventive composition

(28) TABLE-US-00002 TABLE 2 Composition of Tested Blends Composition Component  8*  9* 10* 11 12 13 14 B-1 100 80 70 60 40 30 20 A-1  0 20 30 40 60 70 80 *non-inventive composition

(29) TABLE-US-00003 TABLE 3 Properties of Tested Blends Trials as per ISO Composition standard 1* 2* 3* 4 5 6 7* MFI [gm/10 min] [200° C./10 kg] 49 76 93 106 113 121 75 MFI [gm/10 min] [200° C./5 kg] 6 9.2 10.7 11.6 11 9.2 6.2 lzod [KJ/mm.sup.2] (NB) 70 27.4 5.9 3.0 1.8 2.0 TS [MPa] 4.5 14.0 20.3 30.9 43.8 47.95 61.3 TM (E-Modul) [MPa] 187 664 930 1412 2565 3210 3159 FS [MPa] 5.8 19.3 26.3 37.2 67.7 94.3 68.5 FM [MPa] 208.9 663.0 986.0 1423 2313 3136 3906 VST B50 — 53.0 54.1 59.3 74.0 93.4 100 VST A50 54.7 70.1 79.0 88.4 100 105.5 106 Transparency [%] 84 88.4 89.3 88.3 88.68 88.93 89.93 700-750 nm Haze [%] 39 19.8 16.3 15.2 10.3 9.1 2.6

(30) TABLE-US-00004 TABLE 4 Composition Trials as per ISO std 8* 9* 10* 11 12 13 14 7* MFI [gm/10 min] 76 114 132 140 125 119 116 75 [200° C./10 kg] MFI [gm/10 min] 9.2 8.9 10.2 11.4 14.2 12.6 11.0 6.2 [200° C./5 kg] Izod [KJ/mm.sup.2] (NB) 70.0 5.2 4.0 1.5 1.7 2.0 2.0 TS [MPa] 8.5 17.2 25.5 34.2 45.5 51.2 54.7 61.3 TM (E-Modul) 628 1157 1467 1702 2619 3072 3250 3159 [MPa] FS [MPa] 21.5 28.3 36.2 44.5 69.4 87.4 96.3 68.5 FM [MPa] 597 1167 1422 1740 2449 2883 3246 3906 VST B50 44 50.1 58.8 65.4 79.5 85.6 93 100 VST A50 66.7 70.1 85.8 93.8 103.6 104.9 105.5 106 Transparency [%] 87 90.80 90.17 89.58 89.81 88.77 89.87 89.93 700-750 nm Haze [%] 20 16.1 15.1 12.4 9.3 9.9 9.9 2.6

(31) The test results show that the inventive compositions (cp. 4, 5, 6, 11, 12, 13 and 14) have a high melt flow index in combination with good mechanical, thermal and optical properties.