"Industrial Scale Nanofiber from Molten Plastics" Leonard Torobin PhD, CEO, The Nanofiber Group Richard Findlow, President, The Nanofiber Group

Transcription

1 "Industrial Scale Nanofiber from Molten Plastics" Leonard Torobin PhD, CEO, The Nanofiber Group Richard Findlow, President, The Nanofiber Group 1

2 current best meltblowing : 100 holes (100 holes/inch) Nanofiber Group new technology slide 1

3 slide 1 notes: Attempts by Meltblowing to make nanofibers by increasing extrusion die holes / inch have failed. Their test sample shows fiber diameter spreads too wide to be useful commercially. The Nanofiber Group process uses a totally different physics base than Melt blowing. It allows fiber diameter adjustment from 0.25 microns to 12 microns on the same equipment without shutdown.

4 slide 2

5 slide 2 notes: The Nanofiber Group s latest design allows for very narrow fiber diameter distribution and the ability to add aa specific amount of reinforcing heavy fiber in controlled amounts. The Nanofiber Group finds that the arithmetic average of 0.25 microns fiber diameter represents the lowest diameter of current market interest so this will represent the lower boundary of its commercial product and machine offerings.

6 slide 3 large fiber mode

7 slide 3 notes: The new fiber physics allows fiber diameter size to be adjusted continuously from 0.25 microns up through the upper size range of Melt blowing, i.e. roughly a fiber size of 10 microns. Slide #3 shows a sample of these large fibers. They match those of conventional Melt Blowing yet are produced on the same machine as the 0.25 micron diameter Nanofiber shown in Slide 2.

8 typical submicron nanofiber web slide 4 (Nanofiber Group process)

9 slide 4 notes: Slide 4 shows an early sample of the Group Process polypropylene nanofiber which displays its typical laydown pattern for elevated basis weights. The curled geometry results from a relative absence of stretching stress and may be optimum for particle collection.

10 conventional electrospun nanofiber * slide 5 * Donaldson Filters

11 slide 5 notes: Most nanofibers available today are deposited as a monolayer or at relatively low basis weight. In general, their formation processes cannot be applied to liquid melts and usually require solvent solutions for low viscosities. The sample shown in Slide 5 was provided by the Donaldson Co., an early nanofiber pioneer.

12 MM WATER slide 6 NANOFIBER VS STANDARD MICROGLASS (UNCHARGED EXCEPT WHERE SHOWN) 50 ULPA HEPA SUB-HEPA MERV: H&V standard microglass 40 Nanofiber:a 30 Nanofiber: b nanofiber charged 20 nanofiber, charged Log. (H&V standard m icroglass) * Log. (Nanofiber: b) 10 * ` Log. (nanofiber charged) PENETRATION %, 0.3micron DOP,10.5 ft/min

13 slide 6 notes: In order to address the majority of potential nanofiber product applications, we need to move from low basis weights to higher levels. Slide 6 shows the smooth progression of filter efficiencies by simply increasing fiber bed basis weight. Accordingly, in the slide, the filter efficiencies go from MERVS of less than 12 all the way to filter efficiencies that surpass that of ULPA. Notice that this was done by simply increasing fiber count. Since all the filtration was mechanical only, the efficiencies track closely with the conventional micro glass which is being phased out by the industry due to health concerns. Also shown is the effect of electro charging, which drops the amount of nanofiber required, but raises the possibility of limited filter life due to charge dissipation.

14 nanofiber comparisons ave. size microns basis wt. grams/sq. meter electrospun: bulk nanofiber: standard melt blown: slide 7

15 slide 7 notes: A comparison of basis weights and fiber size of various fiber products

16 A MAJOR PITFALL FOR NANOFIBERS: FIBER BUCKLING slide 8

17 slide 8 notes: A problem, often unanticipated in the manufacture of nanofibers, derives from fiber buckling. This is exacerbated as fiber diameters are decreased in conjunction with low modulus resins. Storage or handling can subject parts of the fiber web to non-uniform pressures which in turn can cause permanent localized deformation and consequential unacceptable variation of web performance.

18 volume 120% compression recovery polypropylene vs Valox nanofiber NANOFIBER PROPRIETARY ORIGINAL 100% COMPRESSED 80% RELEASED 60% RELEASED PLUS 48 HR 40% 20% 0% POLYPROPYLENE NANOFIBER 1 VALOX NANOFIBER slide 9 18

19 slide 9 notes This slide illustrates the buckling problem: The polypropylene sample exhibits permanent deformation, Higher modulus resins such as PET and PBT are more resistant, but are still not adequate for general use.

20 slide 10 Nanofiber with coarse fiber reinforcement 20

21 slide 10 notes A solution to the problem of nanofiber buckling is to use properly dispersed reinforcing fibers which resist buckling because of their large diameters and/or high resin modulus. This is illustrated in slide 10.

22 slide 11 US Patent 6,183,670 to L. Torobin, R.Findlow

23 slide 11 notes The Nanofiber Group has patented a series of processes to facilitate the proper intermixing of nanofibers with reinforcing fibers. Slide 11 is a graphic side view from the patents. The objective is to cause the collision in flight of nascent fibers. This promotes a partial wrapping around of individual nanofibers with individual reinforcing fibers as shown in slide 10. The collision in flight of the fibers results from colliding the output from specific fiber forming cells, some of which are controlled to produce nanofibers, and others reinforcing fibers.

24 slide 12

25 slide 12 notes The next slide shows a top view of the cell array. Since each cell in the array can be controlled to provide fibers with diameters ranging from 0.25 microns until about 12 microns the reinforcing fibers can be distributed in an optimum way. Also, certain of the cells can be fed with other resins selected to impart specific attributes to the resulting composite.

26 slide 13 Melt blown

27 slide 13 notes: Since adsorption capacity of fiber webs improves with decreasing fiber diameter due to increased surface area, composites can be prepared to result in wipers with superior performance. The result is incorporated in a separate patent granted to the Nanofiber Group. As shown in slide 13, the sorptive capacity and speed outperform that of standard wipers by a factor of about 3 due to the increased wiper surface area.

28 slide 14

29 slide 14 notes: The superior performance reported by customers of reinforced wipers made with the patented Nanofiber Group product is exemplified by wipers provided to 3M. In this instance, the Nanofiber Group was responsible for packaging and solvent saturation in addition to fiber production.

30 MM WATER slide 16 BULK POLYESTER NANOFIBER ( UNCHARGED) VS MICROGLASS dop FT/ M I N 0. 3 mi c r on D OP c ha l l e nge 16slide m 16 m-16 ( M ER V16 ( M ER V15 ) ( M ER V14 ) ( M ER V13 ) ( M ER V8 ) ) 16 m-15 m-14 m-13 m-8 14 m PBT NANOFIBER PET NANOFIBER recycled microglass 0 M-16 slide M m penetration, % 15

31 slide 15 notes: This slide provides examples of the diversity of that can be used for nanofiber production. Both virgin and recycle feeds are accommodated and show similar filtration abilities. In general, the filtration efficiencies are somewhat better than their microglass counterparts.

32 Energy Consumption supersonic meltblown slide 17 17

33 slide 17 notes: The energy requirements for fiber production in both the submicron and large fiber regions are shown to be considerably lower than for the counterpart melt blowing. In addition, the capital costs for this novel physics application are lower. These combine to provide a competitive alternative to melt blowing, with a general ability to make nanofibers as a no additional cost add-on.

34 The Nanofiber Group: Including: Nanofiber Filters, LLC Nanofiber Wipers, LLC Nanofiber Applications, LLC Leonard Torobin, PhD Chairman, CEO cell phone: web: manufacturing plant:12760 Airport RD, Maxton, NC, fax: (704) The Nanofiber Group: Including: Nanofiber Filters, LLC Nanofiber Wipers, LLC Nanofiber Applications, LLC Dick Findlow President cell phone: (910) web: manufacturing plant:12760 Airport RD, Maxton, NC,