ULTRA-HIGH FLOW ACRYLONITRILE BUTADIENE STYRENE COPOLYMER COMPOSITIONS

Abstract

ABS molding composition comprising: (a) 50 to 80 wt.-% SAN copolymer (a) (S/AN ratio 78:22 to 65:35, M.sub.w 80,000 to 250,000); (b) 8 to 25 wt.-% graft copolymer (b) consisting of 15 to 60 wt.-% graft sheath (b2) and 40 to 85 wt.-% graft substrate—an agglomerated butadiene rubber latex—(b1), obtained by emulsion polymerization of SAN in presence of agglomerated butadiene rubber latex (b1) (D.sub.50 150 to 800 nm); and (c) 8 to 30 wt.-% SBC block copolymer (vinylarene 58 to 68 wt.-%) comprising diene/vinylarene tapered polymer blocks; exhibiting ultra-high flow melt with good mechanical properties, a process for their preparation and their use for the production of bulky and/or thin walled articles.

Claims

1.-17. (canceled)

18. A thermoplastic molding composition comprising components a, b, c, and d: (a) 50 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 250,000 g/mol; (b) 8 to 25 wt.-% of at least one graft copolymer (b) consisting of 15 to 60 wt.-% of a graft sheath (b2) and 40 to 85 wt.-% of a graft substrate (b1), wherein (b1) is at least one agglomerated butadiene rubber latex and wherein (b1) and (b2) 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 (b2), wherein the styrene and/or acrylonitrile is optionally replaced partially by alphamethylstyrene, methyl methacrylate, maleic anhydride or N-phenylmaleimide, or mixtures thereof, in the presence of the at least one agglomerated butadiene rubber latex (b1) with a median weight particle diameter D.sub.50 of 150 to 800 nm, where the at least one agglomerated rubber latex (b1) is obtained by agglomeration of at least one starting butadiene rubber latex (s-b1) having a median weight particle diameter D.sub.50 of equal to or less than 120 nm; (c) 8 to 30 wt.-% of at least one coupled conjugated diene/monovinylarene block copolymer (c) comprising one or more 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 58 to 68 wt.-%, and the conjugated diene is present in an amount of 32 to 42 wt.-%; and (d) 0 to 5 wt.-% of further additives and/or processing aids (d); where the components a, b, c, and, if present d, sum to 100 wt.-%.

19. The thermoplastic molding composition according to claim 18, comprising: 60 to 75 wt-.% component (a), 8 to 20 wt.-% component (b), 8 to 25 wt.-% component (c), and 0 to 5 wt.-% component (d).

20. The thermoplastic molding composition according to claim 18, comprising: 60 to 70 wt-.% component (a), 8 to 17 wt.-% component (b), 9 to 22 wt.-% component (c), and 0 to 5 wt.-% component (d).

21. The thermoplastic molding composition according to claim 18, wherein copolymer (a) is a copolymer of styrene and acrylonitrile in a weight ratio of from 75:25 to 70:30.

22. The thermoplastic molding composition according to claim 18, wherein M.sub.w of copolymer (a) is 90,000 to 150,000 g/mol.

23. The thermoplastic molding composition according to claim 18, wherein the graft sheath (b2) of graft copolymer (b) is obtained by emulsion polymerization of styrene and acrylonitrile in a weight ratio of 80:20 to 65:35.

24. The thermoplastic molding composition according to claim 18, wherein the agglomerated butadiene rubber latex (b1) of graft copolymer (b) has a median weight particle diameter D.sub.50 of 200 to 600 nm.

25. The thermoplastic molding composition according to claim 18, wherein, based on the total weight of the final block copolymer (c), 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.-%.

26. The thermoplastic molding composition according to claim 18, wherein block copolymer (c) comprises at least three consecutive conjugated diene/monovinylarene tapered polymer blocks.

27. The thermoplastic molding composition according to claim 18, wherein in block copolymer (c) the conjugated diene is 1,3-butadiene and the monovinylarene is styrene.

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

29. The thermoplastic molding composition according to claim 18, where block copolymer (c) 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, B3/S5 are tapered blocks containing a mixture of monovinylarene and conjugated diene, and ˜ is the bond to the coupling agent.

30. The thermoplastic molding composition according to claim 18, wherein in each tapered polymer block of block copolymer (c) the conjugated diene is present in an amount of from 0.6 parts to 4 parts per part monovinylarene in the tapered polymer block.

31. A process for the preparation of the thermoplastic molding composition according to claim 18 by melt mixing the components (a), (b), (c), and, if present, (d), at temperatures in the range of from 180° C. to 250° C.

32. A method of using the thermoplastic molding composition according to claim 18 to produce a shaped article.

33. A shaped article made from the thermoplastic molding composition according to claim 18

34. A method of using thermoplastic molding compositions according to claim 18 for applications in the automotive, household, and healthcare sector.

Description

EXAMPLES

[0230] Test Methods

[0231] Molar Mass M.sub.w

[0232] 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.

[0233] Melt Flow Index (MFI) or Melt Volume Flow Rate (MFR)

[0234] 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.

[0235] Notched Izod Impact Strength (NIIS) Test

[0236] Izod impact tests were performed on notched specimens (ASTM D 256 standard) using an instrument of CEAST, Italy.

[0237] Tensile Strength (TS) and Tensile Modulus (TM) Test Tensile tests (ISO 527) of the blends were carried out at 23° C. using an Universal testing Machine (UTM) of Instron, UK.

[0238] Flexural Strength (FS) and Flexural Modulus (FM) Test

[0239] Flexural test of the blends (ISO 178) was carried out at 23° C. using a UTM of Lloyd Instruments, UK.

[0240] Heat deflection temperature (HDT)

[0241] Heat deflection temperature test was performed on injection molded specimen (ASTM D 648 standard) using a Zwick Roell GmbH instrument.

[0242] VICAT Softening Temperature (VST)

[0243] Vicat softening temperature test was performed on injection molded test specimen (ASTM D 1525-09 standard) using a Zwick Roell GmbH machine. Test is carried out at a heating rate of 120° C./hr (Method B) at 50 N loads.

[0244] Rockwell Hardness (RH)

[0245] Hardness of the injection molded test specimen (ISO-2039/2-11) was tested using a Rockwell hardness tester.

[0246] Materials used:

[0247] Component (a)

[0248] Statistical copolymer (a-1) 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.

[0249] Component (b)

[0250] Fine-Particle Butadiene Rubber Latex (s-b1)

[0251] The fine-particle butadiene rubber latex (s-b1) 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-b1) 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. 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-b1) is characterized by the following parameters, see table 1.

[0252] Latex s-b1-1

[0253] 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.

TABLE-US-00001 TABLE 1 Composition of the butadiene rubber latex s-b1 Latex s-b1-1 Monomer butadiene/styrene 90/10 Seed Latex (wt.-% based on monomers) ./. Emulsifier (wt.-% based on monomers) 2.80 Potassium Persulfate (wt.-% based on monomers) 0.10 Decomposed Potassium Persulfate (parts per 100 parts latex 0.068 solids) Salt (wt.-% based on monomers) 0.559 Salt amount relative to the weight of solids of the rubber 0.598 latex Monomer conversion (%) 89.3 Dw (nm) 87 pH 10.6 Latex solids content (wt.-%) 42.6 K 0.91

K=W*(1−10.4*S)*Dw

[0254] W=decomposed potassium persulfate [parts per 100 parts rubber]

[0255] S=salt amount in percent relative to the weight of solids of the rubber latex

[0256] Dw=weight average particle size (=median particle diameter D.sub.50) of the fine-particle butadiene rubber latex (s-b1)

[0257] Production of the Coarse-Particle, Agglomerated Butadiene Rubber Latices (b1)

[0258] The production of the coarse-particle, agglomerated butadiene rubber latices (b1) was performed with the specified amounts mentioned in table 2. The fine-particle butadiene rubber latex (s-b1) was provided first at 25° C. and was adjusted if necessary with deionized 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-b1) 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-b1) was determined. The solid content of the agglomerated butadiene rubber latex (b1), the pH value and the median weight particle diameter D.sub.50 was determined.

TABLE-US-00002 TABLE 2 Production of the coarse-particle, agglomerated butadiene rubber latices (b1) latex b1 b1-1 b1-2 used latex s-b1 s-b1-1 s-b1-1 concentration latex s-b1 before wt.-% 37.4 37.4 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

[0259] Production of the Graft Copolymers (b) 59.5 wt.-parts of mixtures of the coarse-particle, agglomerated butadiene rubber latices b1-1 and b1-2 (ratio 50: 50, calculated as solids of the rubber latices (b1)) 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 tertdodecylmercaptan were added in 3 hours 30 minutes. 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. 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 (b)) 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.-%). The obtained product is graft copolymer (b-1).

[0260] Component (c)

[0261] c-1: K-Resin® KR20, a styrene butadiene block copolymer (styrene content 62 wt.-%) from Ineos Styrolution, Germany.

[0262] c-2: K-Resin® KRDEV034A, a styrene butadiene block copolymer (styrene content 62 wt.-%) from Ineos Styrolution, Germany.

[0263] Component (d)

TABLE-US-00003 d-1 Ethylene bis stearamide d-2 Polydimethyl siloxane d-3 Distearyl pentaeritritol diphosphite (SPEP) d-4 Magnesium stearate d-5 Magnesium oxide

[0264] Thermoplastic Molding Compositions

[0265] SAN-copolymer (a-1), graft copolymer (b-1), and SBC-block copolymer (c-1) or (c-2), and the afore-mentioned components (d) 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 190 to 220° C. for the different barrel zones. The extruded strands were cooled in a water bath, air-dried and pelletized. Standard test specimens of the obtained blend were injection molded at a temperature of 190 to 230° C. and test specimens were prepared.

TABLE-US-00004 TABLE 3 Composition (in wt.-%) of Tested Blends Example No. 1 2* 3 4 5 Components b-1 19.6 24.5 9.8 14.7 14.7 a-1 68.5 73.4 68.5 68.5 63.6 c-1 — — 19.6 14.7 19.6 c-2 9.8 — — — — Additives (d-1) 1.47 1.47 1.47 1.47 1.47 (d-2) 0.15 0.15 0.15 0.15 0.15 (d-3) 0.15 0.15 0.15 0.15 0.15 (d-4) 0.29 0.29 0.29 0.29 0.29 (d-5) 0.10 0.10 0.10 0.10 0.10 *composition not according to claims

[0266] The residual monomer and solvent content and the mechanical, thermal and flow properties of the tested blends are presented in Tables 4 and 5.

TABLE-US-00005 TABLE 4 Residual Monomer Analysis Example Monomer/solvent (ppm) No. AN Toluene Ethylbenzene Styrene 2* 20 117 15 1067 3 20 105 11 567 4 19 103 13 737 5 16 89 0 640

[0267] The residual monomer and solvent content of the inventive examples 3 to 5 is lower compared to the comparative example 2* without SBC block copolymers.

TABLE-US-00006 TABLE 5 Property Profile of Tested Blends Example No. Properties Unit 1 2* 3 4 5 BY FTIR % AN 24.9 24.8 24.9 24.5 21.2 % BD 12.8 12.2 11.6 12.8 14.3 % ST 62.3 63.0 63.5 62.7 64.5 Melt Flow Rate g/10 min 61 39 98 75 85 Notched Izod Impact kg .Math. cm/cm 21.5 16 5 10 11 Strength 6.4 mm Notched Izod Impact kg .Math. cm/cm 26 23.5 5 15.5 15 Strength 3.2 mm Tensile Strength kg/cm.sup.2 475 500 510 490 435 Tensile Modulus kg/cm.sup.2 27775 29200 30199 29387 27250 Elongation at Break % 32 26 25 33 40 Flexural Strength kg/cm.sup.2 767 832 815 817 739 Flexural Modulus kg/cm.sup.2 26154 29100 28081 28325 25196 Rockwell Hardness R-Scale 103 108 103 105 100 HDT, 1.8 MPa, annealed ° C. 98 100 99 97 100 VST ° C. 96 101 94 95 93

[0268] The blend according to example 3 shows a very high Melt Flow Rate of 98 g/10 min which is extraordinary in comparison to ABS blends of the prior art. Moreover, said blend shows sufficient impact and other mechanical and thermal properties required for applications in the automotive, household and healthcare sector.