High heat resistant ABS molding composition

Abstract

High heat resistant ABS molding compositions for use in the automotive sector, electronics, and household or healthcare sector comprising: (A) 15 to 35 wt.-% ABS graft copolymer (A); (B) 15 to 35 wt.-% a-methylstyrene/acrylonitrile copolymer (B) (weight ratio 95:5 to 50:50); (C) 20 to 40 wt.-% styrene/acrylonitrile copolymer (C) (weight ratio 95:5 to 50:50; M.sub.w 150,000 to 300,000); (D) 10 to 30 wt.-% random terpolymer (D) made from 13 to 27 wt.-% α, β ethylenically unsaturated cyclic anhydride, 60 to 74 wt.-% aromatic vinyl monomer, and 13 to 27 wt.-% maleimide monomer); (E) 0.1 to 5 wt.-%, of at least one elastomeric block copolymer (E) comprising a vinylaromatic monomer block S and an elastomeric random diene/vinylaromatic onomer block B/S; hard phase proportion is 1 to 40 vol.-% and the diene proportion is less than 50 wt.-%; and (F) 0 to 5 wt.-% of further additives and/or processing aids (F).

Claims

1. A thermoplastic molding composition comprising components A, B, C, D, E, and F: (A) 15 to 35 wt.-% of at least one graft copolymer (A) consisting of 15 to 60 wt.-% of a graft sheath (A2) and 40 to 85 wt.-% of a graft substrate (A1), wherein (A1) is at least one agglomerated butadiene rubber latex and wherein (A1) and (A2) sum up to 100 wt.-%, obtained by emulsion polymerization of styrene and acrylonitrile in a weight ratio of 95:5 to 65:35 to obtain a graft sheath (A2), wherein the styrene and/or acrylonitrile is optionally replaced partially by alpha-methylstyrene, methyl methacrylate, maleic anhydride, or mixtures thereof, in the presence of the at least one agglomerated butadiene rubber latex (A1) with a median weight particle diameter D.sub.50 of 150 to 800 nm, wherein the agglomerated rubber latex (A1) is obtained by agglomeration of at least one starting butadiene rubber latex (S-A1) having a median weight particle diameter D.sub.50 of equal to or less than 120 nm; (B) 15 to 35 wt.-% of at least one copolymer (B) of alpha-methylstyrene and acrylonitrile in a weight ratio of from 95:5 to 50:50, wherein the alpha-methylstyrene and/or acrylonitrile is optionally partially replaced by methyl methacrylate, maleic anhydride, and/or 4-phenylstyrene; (C) 20 to 40 wt.-% of at least one copolymer (C) of styrene and acrylonitrile in a weight ratio of from 95:5 to 50:50, wherein the styrene and/or acrylonitrile is optionally partially replaced by methyl methacrylate, maleic anhydride, and/or 4-phenylstyrene; wherein copolymer (C) has a weight average molar mass M.sub.w of 150,000 to 300,000 g/mol; (D) 10 to 30 wt.-% of at least one random terpolymer (D) comprising 13 to 27 wt.-% recurring units of an α, β ethylenically unsaturated cyclic anhydride, 60 to 74 wt.-% recurring units of an aromatic vinyl monomer, and 13 to 27 wt.-% recurring units of a maleimide monomer; (E) 0.1 to 5 wt.-%, of at least one elastomeric block copolymer (E) comprising at least one block S which forms a hard phase and incorporates units of a vinylaromatic monomer and at least one elastomeric block B/S which forms a soft phase and incorporates both units of a vinylaromatic monomer and of a conjugated diene, wherein S is the vinylaromatic block and B/S is the soft phase, wherein the block is built up randomly from diene units and vinylaromatic units, and wherein the glass transition temperature Tg of the block S is above 25° C., and that of the block B/S is below 25° C., and the phase volume ratio of block S to block B/S is selected so that the proportion of hard phase in the entire block copolymer is from 1 to 40% by volume and the proportion of the diene is less than 50 wt.-%, based on the entire block copolymer (E); (F) 0 to 5 wt.-% of further additives and/or processing aids (F); wherein the components A, B, C, D, E, and, if present, F, sum to 100 wt.-%.

2. The thermoplastic molding composition according to claim 1, comprising: 20 to 30 wt.-% component (A), 20 to 30 wt.-% component (B), 25 to 35 wt.-% component (C), 15 to 25 wt.-% component (D), 0.3 to 3 wt.-% component (E), and 0 to 5 wt.-% component (F).

3. The thermoplastic molding composition according to claim 1, wherein component (D) has a glass transition temperature T.sub.G in the range from 180 to 200° C.

4. The thermoplastic molding composition according to claim 1, wherein component (D) is a terpolymer consisting of recurring units of maleic anhydride, styrene, and N-phenyl maleimide.

5. The thermoplastic molding composition according to claim 1, wherein the B/S block of block copolymer (E) is composed of 75 to 30 wt.-% of vinylaromatic monomer and 25 to 70 wt.-% of diene.

6. The thermoplastic molding composition according to claim 1, wherein block copolymer (E) is made from a monomer composition consisting of 25 to 39 wt.-% of diene and 75 to 61 wt.-% of the vinylaromatic monomer.

7. The thermoplastic molding composition according to claim 1, wherein block copolymer (E) is one whose soft phase is divided into blocks (B/S).sub.1 -(B/S).sub.2; (B/S).sub.1 -(B/S).sub.2 -(B/S).sub.1, and (B/S).sub.1 -(B/S).sub.2 -(B/S).sub.3; whose vinylaromatic/diene ratio differs in the individual blocks B/S or changes continuously within a block, the glass transition temperature T.sub.g of each sub-block being below 25° C.

8. The thermoplastic molding composition according to claim 1, wherein in block copolymer (E) the vinylaromatic monomer is styrene and the conjugated diene is 1,3-butadiene.

9. The thermoplastic molding composition according to claim 1, wherein component (B) is a copolymer having a molecular weight Mw of from 20,000 to 220,000 g/mol and a melt flow index (MFI) of 5 to 9 g/10 min.

10. The thermoplastic molding composition according to claim 1, wherein component (E) is partly replaced by at least one elastomeric block copolymer (E′), wherein (E′) is a coupled conjugated diene/monovinylarene block copolymer comprising one or more conjugated diene/monovinylarene tapered polymer blocks, wherein in the final block copolymer all conjugated diene is incorporated into the tapered blocks, and, based on the total weight of the final block copolymer, the monovinylarene is present in an amount of 55 to 80 wt.-% and the conjugated diene is present in an amount of 20 to 45 wt.-%.

11. A process for the preparation of the thermoplastic molding composition according to claim 1 by melt mixing the components (A), (B), (C), (D), (E), and, if present, (F), at temperatures in the range of from 160° C. to 400° C.

12. A molded article made from the thermoplastic molding composition according to claim 1.

13. A shaped article for applications in the automotive, household, and healthcare sectors and in the electronics industry comprising the thermoplastic molding composition according to claim 1.

14. The shaped article of claim 13, wherein the shaped article is a thermoformed article, an extruded article, an injection molded article, a calendared article, a blow molded article, a compression molded article, a press sintered article, a deep drawn article, or a sintered article.

15. A thermoplastic molding composition comprising components A, B, C, D, E′, and F: (A) 15 to 35 wt.-% of at least one graft copolymer (A) consisting of 15 to 60 wt.-% of a graft sheath (A2) and 40 to 85 wt.-% of a graft substrate (A1), wherein (A1) is at least one agglomerated butadiene rubber latex and wherein (A1) and (A2) sum up to 100 wt.-%, obtained by emulsion polymerization of styrene and acrylonitrile in a weight ratio of 95:5 to 65:35 to obtain a graft sheath (A2), wherein the styrene and/or acrylonitrile is optionally replaced partially by alpha-methylstyrene, methyl methacrylate, maleic anhydride, or mixtures thereof, in the presence of the at least one agglomerated butadiene rubber latex (A1) with a median weight particle diameter D.sub.50 of 150 to 800 nm, wherein the agglomerated rubber latex (A1) is obtained by agglomeration of at least one starting butadiene rubber latex (S-A1) having a median weight particle diameter D.sub.50 of equal to or less than 120 nm; (B) 15 to 35 wt.-% of at least one copolymer (B) of alpha-methylstyrene and acrylonitrile in a weight ratio of from 95:5 to 50:50, wherein the alpha-methylstyrene and/or acrylonitrile is optionally partially replaced by methyl methacrylate, maleic anhydride, and/or 4-phenylstyrene; (C) 20 to 40 wt.-% of at least one copolymer (C) of styrene and acrylonitrile in a weight ratio of from 95:5 to 50:50, wherein the styrene and/or acrylonitrile is optionally partially replaced by methyl methacrylate, maleic anhydride, and/or 4-phenylstyrene; wherein copolymer (C) has a weight average molar mass M.sub.w of 150,000 to 300,000 g/mol; (D) 10 to 30 wt.-% of at least one random terpolymer (D) comprising 13 to 27 wt.-% recurring units of an α, β ethylenically unsaturated cyclic anhydride, 60 to 74 wt.-% recurring units of an aromatic vinyl monomer, and 13 to 27 wt.-% recurring units of a maleimide monomer; (E′) 0.1 to 5 wt.-%, of at least one elastomeric block copolymer (E′), wherein (E′) is a coupled conjugated diene/monovinylarene block copolymer comprising one or more conjugated diene/monovinylarene tapered polymer blocks, wherein in the final block copolymer all conjugated diene is incorporated into the tapered blocks, and, based on the total weight of the final block copolymer, the monovinylarene is present in an amount of 55 to 80 wt.-%, and the conjugated diene is present in an amount of 20 to 45 wt.-%; (F) 0 to 5 wt.-% of further additives and/or processing aids (F); wherein the components A, B, C, D, E′, and, if present, F, sum to 100 wt.-%.

16. The thermoplastic molding composition according to claim 15, comprising: 20 to 30 wt.-% component (A), 20 to 30 wt.-% component (B), 25 to 35 wt.-% component (C), 15 to 25 wt.-% component (D), 0.3 to 3 wt.-% component (E′), and 0 to 5 wt.-% component (F).

17. The thermoplastic molding composition according to claim 15, wherein block copolymer (E′) comprises at least three consecutive conjugated diene/monovinylarene tapered polymer blocks.

18. The thermoplastic molding composition according to claim 15, wherein in each individual tapered polymer block of block copolymer (E′) 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.

19. The thermoplastic molding composition according to claim 15, wherein block copolymer (E′) comprises at least one polymer chain of the formula
S1-S2-B1/S3-B2/S4-B3/S5˜, wherein S1 and S2 are monovinylarene blocks, blocks B1/S3, B2/S4, and B3/S5 are tapered blocks containing a mixture of monovinylarene and conjugated diene, and ˜ is the bond to a coupling agent.

20. The thermoplastic molding composition according to claim 15, wherein component (B) is a copolymer having a molecular weight Mw of from 20,000 to 220,000 g/mol and a melt flow index (MFI) of 5 to 9 g/10 min.

21. A process for the preparation of the thermoplastic molding composition according to claim 15 by melt mixing the components (A), (B), (C), (D), (E′), and, if present, (F), at temperatures in the range of from 160° C. to 400° C.

22. A molded article made from the thermoplastic molding composition according to claim 15.

23. A shaped article for applications in the automotive, household, and healthcare sectors and in the electronics industry comprising the thermoplastic molding composition according to claim 15.

24. The shaped article of claim 23, wherein the shaped article is a thermoformed article, an extruded article, an injection molded article, a calendared article, a blow molded article, a compression molded article, a press sintered article, a deep drawn article, or a sintered article.

Description

EXAMPLES

(1) Test Methods

(2) Particle Size Dw/D.sub.50

(3) For measuring the weight average particle size Dw (in particular the median weight particle diameter D50) with the disc centrifuge DC 24000 by CPS Instruments Inc. equipped with a low density disc, an aqueous sugar solution of 17.1 mL with a density gradient of 8 to 20% by wt. of saccharose in the centrifuge disc was used, in order to achieve a stable flotation behavior of the particles. A polybutadiene latex with a narrow distribution and a mean particle size of 405 nm was used for calibration. The measurements were carried out at a rotational speed of the disc of 24,000 r.p.m. by injecting 0.1 mL of a diluted rubber dispersion into an aqueous 24% by wt. saccharose solution. The calculation of the weight average particle size Dw was performed by means of the formula
D.sub.w=sum(n.sub.i*d.sub.i.sup.4)/sum(n.sub.i*d.sub.i.sup.3) n.sub.i: number of particles of diameter d.sub.i.

(4) Molar Mass M.sub.w

(5) 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.

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

(7) Tensile test (ASTM D 638) of ABS blends was carried out at 23° C. using a Universal testing Machine (UTM) of Lloyd Instruments, UK.

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

(9) Flexural test of ABS blends (ASTM D 790 standard) was carried out at 23° C. using a UTM of Lloyd Instruments, UK.

(10) Notched Izod Impact Strength (NIIS) Test

(11) Izod impact tests were performed on notched specimens (ASTM D 256 standard) using an instrument of CEAST (part of Instron's product line), Italy.

(12) Heat Deflection Temperature (HDT)

(13) Heat deflection temperature test was performed on injection molded specimen (ASTM D 648 standard) using a CEAST, Italy instrument.

(14) VICAT Softening Temperature (VST)

(15) Vicat softening temperature test was performed on injection molded test specimen (ASTM D 1525-09 standard) using a CEAST, Italy machine. Test is carried out at a heating rate of 120° C./hr (Method B) at 50 N loads.

(16) Rockwell Hardness (RH)

(17) Hardness of the injection molded test specimen (ISO-2039/2-11) was tested using a Rockwell hardness tester.

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

(19) MFI/MFR test was performed on ABS pellets (ISO 1133 standard, ASTM 1238, 220° C./10 kg load) using a MFI-machine of CEAST, Italy.

(20) Materials used:

(21) Component (A)

(22) Fine-Particle Butadiene Rubber Latex (S-A1)

(23) The fine-particle butadiene rubber latex (S-A1) which is used for the agglomeration step was produced by emulsion polymerization using tert-dodecylmercaptan as chain transfer agent and potassium persulfate as initiator at temperatures from 60° to 80° C. The addition of potassium persulfate marked the beginning of the polymerization. Finally the fine-particle butadiene rubber latex (S-A1) was cooled below 50° C. and the non reacted monomers were removed partially under vacuum (200 to 500 mbar) at temperatures below 50° C. which defines the end of the polymerization.

(24) Then the latex solids (in % per weight) were determined by evaporation of a sample at 180° C. for 25 min. in a drying cabinet. The monomer conversion is calculated from the measured latex solids. The butadiene rubber latex (S-A1) is characterized by the following parameters, see table 1.

(25) Latex S-A1-1

(26) No seed latex is used. As emulsifier the potassium salt of a disproportionated rosin (amount of potassium dehydroabietate: 52 wt.-%, potassium abietate: 0 wt.-%) and as salt tetrasodium pyrophosphate is used.

(27) TABLE-US-00001 TABLE 1 Composition of the butadiene rubber latex S-A1 Latex S-A1-1 Monomer butadiene/styrene 90/10 Seed Latex (wt. -% based on monomers) ./. Emulsifier (wt. -% based on monomers) 2.80 Potassium Persulfate 0.10 (wt. -% based on monomers) Decomposed Potassium Persulfate 0.068 (parts per 100 parts latex solids) Salt (wt. -% based on monomers) 0.559 Salt amount relative to the weight 0.598 of solids of the rubber latex Monomer conversion (%) 89.3 Dw (nm) 87 pH 10.6 Latex solids content (wt. -%) 42.6 K 0.91 K = W * (1 − 1.4 * S) * Dw

(28) W=decomposed potassium persulfate [parts per 100 parts rubber]

(29) S=salt amount in percent relative to the weight of solids of the rubber latex

(30) Dw=weight average particle size (=median particle diameter D.sub.50) of the fine-particle butadiene rubber latex (S-A1)

(31) Production of the Coarse-Particle, Agglomerated Butadiene Rubber Latices (A1)

(32) The production of the coarse-particle, agglomerated butadiene rubber latices (A1) was performed with the specified amounts mentioned in table 2. The fine-particle butadiene rubber latex (S-A1) was provided first at 25° C. and was adjusted if necessary with de-ionized water to a certain concentration and stirred. To this dispersion an amount of acetic anhydride based on 100 parts of the solids from the fine-particle butadiene rubber latex (S-A1) as fresh produced aqueous mixture with a concentration of 4.58 wt.-% was added and the total mixture was stirred for 60 seconds. After this the agglomeration was carried out for 30 minutes without stirring. Subsequently KOH was added as a 3 to 5 wt.-% aqueous solution to the agglomerated latex and mixed by stirring. After filtration through a 50 μm filter the amount of coagulate as solid mass based on 100 parts solids of the fine-particle butadiene rubber latex (S-A1) was determined. The solid content of the agglomerated butadiene rubber latex (A), the pH value and the median weight particle diameter D.sub.50 was determined.

(33) TABLE-US-00002 TABLE 2 Production of the coarse-particle, agglomerated butadiene rubber latices (A1) latex A1 A1-1 A1-2 used latex S-A1 S-A1-1 S-A1-1 concentration latex S-A1 wt. -% 37.4 37.4 before agglomeration amount acetic anhydride parts 0.90 0.91 amount KOH parts 0.81 0.82 concentration KOH solution wt. -% 3 3 solid content latex A1 wt. -% 32.5 32.5 coagulate parts 0.01 0.00 pH 9.0 9.0 D.sub.50 nm 315 328

(34) Production of the Graft Copolymers (A)

(35) 59.5 wt.-parts of mixtures of the coarse-particle, agglomerated butadiene rubber latices A1-1 and A1-2 (ratio 50:50, calculated as solids of the rubber latices (A1)) were diluted with water to a solid content of 27.5 wt.-% and heated to 55° C. 40.5 wt.-parts of a mixture consisting of 72 wt.-parts styrene, 28 wt.-parts acrylonitrile and 0.4 wt.-parts tert-dodecylmercaptan were added in 3 hours 30 minutes.

(36) At the same time when the monomer feed started the polymerization was started by feeding 0.15 wt.-parts cumene hydroperoxide together with 0.57 wt.-parts of a potassium salt of disproportionated rosin (amount of potassium dehydroabietate: 52 wt.-%, potassium abietate: 0 wt.-%) as aqueous solution and separately an aqueous solution of 0.22 wt.-parts of glucose, 0.36 wt.-% of tetrasodium pyrophosphate and 0.005 wt.-% of iron-(II)-sulfate within 3 hours 30 minutes.

(37) The temperature was increased from 55 to 75° C. within 3 hours 30 minutes after start feeding the monomers. The polymerization was carried out for further 2 hours at 75° C. and then the graft rubber latex (=graft copolymer A) was cooled to ambient temperature. The graft rubber latex was stabilized with ca. 0.6 wt.-parts of a phenolic antioxidant and precipitated with sulfuric acid, washed with water and the wet graft powder was dried at 70° C. (residual humidity less than 0.5 wt.-%).

(38) The obtained product is graft copolymer (A-I).

(39) Component (B)

(40) Statistical copolymer (B-I) from alphamethylstyrene and acrylonitrile with a ratio of polymerized styrene to acrylonitrile of 65:35 with a weight average molecular weight Mw of about 200,000 g/mol, a polydispersity of Mw/Mn of 2.5 and a melt volume flow rate (MVR) (220° C./10 kg load) of 6 to 7 mL/10 minutes, produced by free radical solution polymerization.

(41) Component (C)

(42) Statistical copolymer (C-I) from styrene and acrylonitrile with a ratio of polymerized styrene to acrylonitrile of 72:28 with a weight average molecular weight Mw of 185,000 g/mol, a polydispersity of Mw/Mn of 2.5 and a melt volume flow rate (MVR) (220° C./10 kg load) of 6 to 7 mL/10 minutes, produced by free radical solution polymerization.

(43) Component (D)

(44) D-I: Denka IP grade MS-NJP (styrene-N-phenylmaleimide-maleic anhydride-terpolymer, T.sub.G 185° C.) obtained from Denka Company, Japan.

(45) Component (E′)

(46) E′-1: K-resin® KR 20 (styrene butadiene block copolymer) from Ineos Styrolution, Germany.

(47) Component (F)

(48) TABLE-US-00003 F-1 Penta erythritol tetra stearate (PETS) F-2 Magnesium stearate F-3 Magnesium oxide F-4 Distearyl pentaeritritol diphosphite (SPEP) F-5 Carbon black master batch PLASBLAK ® SA 3176 from Cabot Corporation, USA

(49) Thermoplastic Compositions

(50) Graft rubber polymer (A-I), AMSAN-copolymer (B-I), SAN-copolymer (C-I), terpolymer (D-I), component (E′-1), and the afore-mentioned components (F) were mixed (composition see Table 3, 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 230 to 260° C. for the different barrel zones. The extruded strands were cooled in a water bath, air-dried and pelletized.

(51) Standard test specimens (ASTM test bars) of the obtained blend were injection moulded at a temperature of 220 to 250° C. and test specimens were prepared for mechanical testing. The test results are presented in Table 4.

(52) TABLE-US-00004 TABLE 3 Molding Compositions Ex. 1 Ex. 2 Ex. 3 component wt. -% wt. -% % A-I 24.14 24.03 23.57 D-I 19.31 19.22 18.86 B-I 24.14 24.03 23.57 C-I 28.97 28.83 28.29 E′-1 0.48 0.96 2.83 F-1 0.97 0.96 0.94 F-2 0.29 0.29 0.28 F-3 0.10 0.10 0.09 F-4 0.14 0.14 0.14 F-5 1.45 1.44 1.41 Total 100.00 100.00 100.00

(53) TABLE-US-00005 TABLE 4 Properties of the Tested Molding Compositions Ex. 1 Ex. 2 Ex. 3 Melt Flow Rate, g/10 min 3.0 3.1 3.2 NIIS, kg.cm/cm, 6.4 mm 14.5 16.5 14 NIIS, kg.cm/cm, 3.2 mm 18.5 19.5 20 TS, kg/cm.sup.2 560 545 540 TM, kg/cm.sup.2 29750 28950 28650 Elongation at Break, % 8 10 11 FS, kg/cm.sup.2 990 955 954 FM, kg/cm.sup.2, 30600 29400 29000 RH, R-Scale, 115 114 113 HDT, ° C., Annealed 110 110 109 VST, ° C. 121 120 120

(54) Table 4 shows that the molding compositions according to the invention (Examples 1 to 3) have a high heat deflection temperature (110° C., 109° C.), enhanced impact properties and can be processed easily (MFR of at least 3.0).