A Novel Micro-Batch Mixer That Scales To The Single Screw Extruder

Transcription

1 A Novel Micro-Batch Mixer That Scales To The Single Screw Extruder By Keith Luker, Randcastle Extrusion Systems, Inc., Cedar Grove, NJ Jennifer K. Lynch, Rutgers University Thomas J. Nosker,, Rutgers University

2 Co-Authors Jennifer Lynch, of Rutgers Tom Nosker,, of Rutgers

3 Background Batch mixers mix.

4 Background Batch mixers mix. Single Screw Extruders (SSE) do not mix.

5 Background Batch mixers mix. Single Screw Extruders (SSE) do not mix. Therefore, to suggest making a batch mixer to scale to a single screw extruder, is an oxymoron.

6 Background Until Antec 07, few took the SSE as a serious compounder.

7 Background Until Antec 07, few took the SSE as a serious compounder. At Antec 07, an SSE was described that: Compounded to the 500 nm scale.

8 Background Until Antec 07, no one took the SSE as a serious compounder. At Antec 07, an SSE was described that: Compounded to the 500 nm scale. Vented over a thin film.

9 Background Until Antec 07, no one took the SSE as a serious compounder. At Antec 07, an SSE was described that: Compounded to the 500 nm scale. Vented over a thin film. Used 3 vents in a 36/1 L/D

10 Background Until Antec 07, no one took the SSE as a serious compounder. At Antec 07, an SSE was described that: Compounded to the 500 nm scale. Vented over a thin film. Used 3 vents in a 36/1 L/D Created multiple elongational flow fields the same mechanism as the parallel twin compounder.

11 Background: Yesterday Antec 08 A variant of this 07 SSE reported the ability to compound thermally sensitive materials: EVOH in multilayer regrind.

12 Background: Yesterday Antec 08 A variant of this 07 SSE reported the ability to compound thermally sensitive materials: EVOH in multilayer regrind. Cellulose and oil

13 Background: Yesterday Antec 08 A variant of this 07 SSE reported the ability to compound thermally sensitive materials: EVOH in multilayer regrind. Cellulose and oil RPVC Pellets at unheard of high screw speeds.

14 Output RPVC Pellets 1 Inch 36/1 Extruder Grams/Minute 8.5 kg/h Screw RPM

15 Stock Temperature RPVC Pellets 25 mm, 36/1 Extruder Degrees C (Flush) Immersion Depth (mm) (Through a 25 mm bore) 96 rpm 81 rpm 60 rpm 46 rpm 30 rpm

16 Background: Yesterday Antec 08 A variant of this 07 SSE reported the ability to compound thermally sensitive materials: EVOH in multilayer regrind. Cellulose and oil RPVC Pellets at unheard of high screw speeds. RPVC Powder currently dominated by the conical twin now now processed easily at even higher screw speed and scaled up to production!

17 Background: Yesterday Antec 08 RPVC Powder: 25 mm: 180 RPM Melt 177C 13.2 kg/hr

18 Background: Yesterday Antec 08 RPVC Powder: 25 mm: 180 RPM Melt 177C 13.2 kg/hr 63 mm: 70 RPM Melt kg/hr

19 Background: SSE Compounding SFEM Coloring Vinyl Film Flexible PVC pellets/0.5% red/0.5% yellow concentrate UC Mixer SFEM

20 Background: SSE Compounding SFEM Single Screw Mixer Comparison 10% Elastomer & LDPE UC Mixer Double Wave SFEM

21 Background: SSE Compounding SFEM Single Screw vs Twin Screw Continuous: 20PS/80PE SFEM Single Screw Twin Screw RUTGERS THE STATE UNIVERSITY OF NEW JERSEY Advanced Materials via Immiscible Polymer Processing A Cooperative Center for Research, Development and Commercialization

22 Background: SSE Compounding SFEM 10 microns Picture courtesy Rutgers. Single Screw SFEM RUTGERS THE STATE UNIVERSITY OF NEW 2,000 X Note: Material viscosity different. 10 microns Right picture, Antec 95, CO-CONTINUITY AND PHASE INVERSION IN HDPE/PS BLENDS: THE ROLE OF INTERFACIAL MODIFICATION by Daniel Bourry and Basis D. Favis Advanced Materials via Immiscible Polymer Processing A Cooperative Center for Research, Development and Commercialization 2,000 X

23 Background: SSE Compounding SFEM Ceramic Nano-Composites PMMA Pellets & 5% Nano Ceramic 30 to 60 nm 5,000 X 10,000X 50,000X RUTGERS THE STATE UNIVERSITY OF NEW JERSEY Advanced Materials via Immiscible Polymer Processing A Cooperative Center for Research, Development and Commercialization

24 Background: SSE Compounding SFEM Single Wall Carbon Nano Tubes This picture shows untangled CNT s

25 Background: SSE Compounding SFEM 2% Carbon Nano-Tubes & PC 100,000 X 100,000 X (Enhanced)

26 Background: SSE Compounding SFEM 5% Carbon Nano-Tubes In Acetal Conductive to Dissapative Range Multi-wall CNT s tested IEC 60093: 35 to 85 Ohms/sq

27 Background: SSE Compounding SFEM Wood Flour & LDPE Pellets 25% Flour 40% Flour

28 Background: SSE Compounding SFEM Wood Flour & RPVC Powder 100% RPVC Powder 60% RPVC 40% Woodflour Before Degassing 1 x Tensile Bar 1 x Tensile Bar

29 Background: SSE Compounding SFEM RPVC Pellets & 15% Calcium Carbonate

30 Background: SSE Compounding SFEM 35% Calcium Carbonate Powder With PP Pellets: Two Vents

31 Background: SSE Compounding SFEM The Elongator is a Spiral Fluted Elongational Mixer. Generically: SFEM.

32 Background Micro-batch mixers useful for rare or expensive ingredients.

33 Background Micro-batch mixers useful for rare or expensive ingredients. Several types are known: A miniature conical twin screw with a recirculation loop. A cup and rotor mixer. An internal batch mixer with roller blades. Miniature dual pistons driving material back and forth.

34 Purpose of This Study Find out how well the SFEM SSE compares to the new micro batch mixer.

35 Experimental: Macroscopic: Extrude samples with SFEM and compare to the micro-batch mixer.

36 Experimental: Macroscopic: Extrude samples with SFEM and compare to the micro-batch mixer. Microscopic: Look at the immiscible blends of polystyrene and polyethelene and see if the domains compare.

37 Historically Single Screw Mixers Push! Push to create melting. Then push after melting for mixing as shear.

38 Union Carbide Mixer (aka Maddocks Mixer) C1 Resistance Zone C2

39 Twisted UC Mixer Is An Egan Mixer With Shaded Resistance Zone And Channels Flighted Barrier (B) C2 RZ C1 C1 dead ends into B causing resistance. Pressure, generated upstream and by the spiral geometry forces material over the shaded resistance zone (RZ) where the material is sheared.

40 Pushing Is Bad For Mixing A-B-B-B-B-A

41 Pushing Is Bad For Mixing A-B-B-B-B-A B A- -A

42 Since Pushing Equals Bad A-B-B-B-B-A We must need a new force! B A- -A

43 Suppose We Pull? A-B-B-B-B-A

44 Then A-B-B-B-B-A

45 Then A B B B B -A

46 Then A B B B B - A

47 Pulling Is Good For Mixing! A B B B B - A The smaller the domains, the better the mixing.

48 Suppose We Only Want To Melt? A-A-A-A-A-A

49 Pulling Is Good For Melting Too! A A A A A - A

50 New Generation of Mixers Pull And Pull Right Away AFEM

51 How Does the SFEM Work? P = Pump C = Channel P2 C2 P1 C1 C3 AFEM

52 Imagine A Screw Without A Flight At The End

53 In The Smooth Section, What Path Will A Particle Take?

54 A Spiral Pressure Flow Drag Flow

55 If You Stop The Feed Pressure Flow Drag Flow

56 Material Is Pumped In A Circle Pressure Flow Drag Flow

57 So, A Smooth Section Is A Radial Pump Pressure Flow Drag Flow

58 End View Of Radial Pump s Particle Path Drag Flow

59 Suppose You Put Two Channels Into The Smooth Section P1 C1 C2 P2 0 P = Pump C = Channel Drag Flow

60 Cross Section of AFEM or SFEM C2 P1 C1 P2 C3 P = Pump C = Channel

61 Fine Elongation P1 C1 Region Of Fine Elongation In the approach to the first pump, material experiences fine elongation at low pressure Lowest pressure means the lowest possible heat rise! Zero is the lowest.

62 Bi-Lobal Kneading Disc P2 C2 P1 C1 C3 Q WLG Outline of twin s Bi-lobal kneading disc In the approach to the pump, the polymer cannot know whether it is in a single or a twin screw.

63 Shear In P1 Is Pure Barrel Velocity is high C2 V=0 C1 There is no pressure flow pushing material into P1 only drag flow. Shear mixing is maximized. Heat rise is minimized.

64 Two Dimensional Elongation Barrel Velocity is high C1 C2 V=0 Exiting P1, material is released from P1 but still stuck to the barrel surface. Material extends two dimensionally.

65 Thin Film Created For Venting C2 P1 C1 P2 C3

66 SFEM Vent positions

67 SFEM End of Second C3 P = Pump C = Channel P2 C2 P1 C1 C3 End of Second C1 P1 P2 Flight End of Second C2 Beginning of First C1

68 Batch Mixer Element P2 C3 C2 C1 P1

69 Batch Mixer Element Pellets/Powder Plus Die hole is covered during compounding then exposed during extrusion

70 Batch Mixer Element: Flat View Seal C3 C2 C1 P2 P1

71 Micro Batch Mixer

72 Batch Mixer Cooling Experiments Polypropylene + 1% Red Mixed for 2.5 minutes at 4.3 rpm

73 Batch Mixer Cooling Experiments Polypropylene + 1% Red Mixed for 2.5 minutes at 4.3 rpm

74 Batch Mixer Cooling Experiments Polypropylene + 1% Red Mixed for 2.5 minutes at 4.3 rpm

75 Batch Mixer Cooling Experiments Polypropylene + 1% Red Mixed for 2.5 minutes at 4.3 rpm

76 Batch Mixer Cooling Experiments Polypropylene + 1% Red Mixed for 3.0 minutes at 4.3 rpm

77 Batch Mixer Cooling Experiments Polypropylene + 1% Red Mixed for 3.0 minutes at 4.3 rpm

78 Batch Mixer Cooling Experiments Polypropylene + 1% Red Mixed for 3.0 minutes at 4.3 rpm

79 Batch Mixer Cooling Experiments 2.5 Minutes 3.0 Minutes At 4.3 rpm

80 Batch Mixer Cooling Experiments Polypropylene + 1% Red Mixed for 4.0 minutes at 4.3 rpm

81 Batch Mixer Cooling Experiments Polypropylene + 1% Red Mixed for 4.0 minutes at 4.3 rpm

82 Batch Mixer Cooling Experiments Polypropylene + 1% Red Mixed for 4.0 minutes at 4.3 rpm

83 Batch Mixer Cooling Experiments 2.5 Minutes 3.0 Minutes 4.0 Minutes At 4.3 rpm ~14 Revolutions Total

84 1% Red Film and 1% Red Rod From Micro-Batch Mixer

85 10% Elastomer & LDPE SFEM SFEM Double Wave Batch Mixer Extruder Extruder

86 Batch Mixer: Multiple Batch Test: RPVC 1. Process 15 Grams 2. Extrude 5 grams 3. Close die door. 4. Repeat #2 and #3 five more times for a 30 grams total. 5. RPVC still not yellowed.

87 35% Calcium Carbonate & PP SFEM Extruder SFEM Batch Mixer

88 Continuous: 20PS/80HDPE Globules Domains: 0.2 to 2 Micron Batch Mixer 24/1 Extruder, 2 SFEM (A) (B) (C) (D)

89 Co-continuous:30PS/70HDPE 3D Puzzle Domains: 02 to 20 + Micron Batch Mixer 24/1 Extruder, 2 SFEM (E) (F) (G) (H)

90 Discussion/Conclusions: The SFEM Mixer and Extruder: Have very similar physical geometry yielding very similar levels of mixedness. The micro-batch mixer works on a time scale similar to extrusion.

91 Discussion/Conclusions: The SFEM comparisons represent major scenarios in single screw extrusion. Color Thermally sensitive materials High filler levels Melt Blending

92 Discussion/Conclusions: The SFEM mixer: Extrudes a strand! Strands are easy to pelletize. Pellets are the proper feed stock for processing equipment. Avoids degradation. Is really fast so R & D mixtures prepared in the Micro batch mixer will speed results and scale to extrusion.

93 Thanks To: Jennifer Lynch and Tom Nosker of Rutgers for the pictures of the PS/PE blends and the ceramic nano particles. Very special thanks to Jennifer Lynch for her effort, patience, advise and gracious style. RUTGERS THE STATE UNIVERSITY OF NEW JERSEY Advanced Materials via Immiscible Polymer Processing A Cooperative Center for Research, Development and Commercialization

94 Thank You PRESENTED BY Keith Luker President Randcastle Extrusion Systems, Inc. Questions?