EVALCA Technical Information. Purge Compound ETC-103

Transcription

1 EVALCA Technical Information Purge Compound ETC-103 ETC-103 is a purge resin, developed for purging extruders running ethylene vinyl alcohol (EVOH) and for improved transitioning from EVOH extrusion to nylon or other polyolefins. ETC-103 can also be used for equipment shutdowns. General Properties of ETC-103 Property Condition Unit ETC-103 Melt Temperature C 110 Melt Index 190 C / 2160gm g/10 min. 1.0 Density 20 C g/cc ETC-103 Design EVOH adhering to extruder barrel, adapter and die surfaces is subject to extrusion temperatures for long periods of time and tends to both crosslink and degrade. New EVOH or other polymer entering the extruder can be contaminated with this build up of EVOH. Transitions to other materials, especially nylon, can cause appearance of mixed EVOH/nylon or other polyolefin gels, and require long, costly purges. ETC-103 efficiently removes residual EVOH from extruder systems and prevents gels from forming. ETC-103 is a non-abrasive, non gassing purge compound containing additives which chemically and physically purge EVOH out of extrusion systems with short purge times and small amounts of scrap, boosting production yields and film quality. ETC-103 consists of low density polyethylene (LDPE) as the base material and ingredients which are not hazardous to food packaging applications. ETC-103 Uses ETC-103 can be used in the following situations: SHUTDOWN purges - for situations where equipment will be shutdown for a longer period of time, such as weekends and holidays, EVOH can be purged out with ETC-103 and the equipment shutdown. Production can be restarted with ETC-103 and a changeover made to EVOH without any intermediate resins. SHORT-STOP purges - for situations where heavy buildup of EVOH is suspected, equipment design is complex or a transition to another material such as nylon is planned, stopping extruder for 15~30 minutes after purging in ETC-103 will promote a very effective purge. ETC-103 can be followed by normal EVOH resin or new material to be run, without intermediate resins. 1

2 RUNNING purges - for purging EVOH extruders on the fly and for quick cleanup, ETC-103 can be introduced and extruders purged for 15~30 minutes before returning directly to EVOH extrusion. ETC-103 Performance Evaluation Tests conducted at EVALCA demonstrate how effectively ETC-103 removes residual EVOH from extrusion systems and prevents gels from forming both for EVOH to nylon transitions and for shutdown and restart of systems. Two extrusion tests were conducted to evaluate the purging performance of ETC-103 and various other purging materials including LDPE and a commercial purge. EVOH Shutdown and Purge Test Run EVOH at 550 F (287 C) for 4.75 hours Extruder shutdown 4 times Purge for 30 minutes Shutdown extruder 12 hours Restart extruder Run at normal conditions for 3 hours Transition Test - EVOH to NYLON Purge. Run EVOH at 460 F (237 C) for 3 hours Purge for 30 or 60 minutes Run NYLON for 4 hours (2500m of film) All tests were conducted on commercial scale 2-inch (50.82-mm) diameter, single screw extruder with a flat film die. Gel levels were measured with a Futec TM video web inspection system. Futec TM is a high resolution scanning system which has the ability to measure microscopic gels that are invisible to the human eye. Evaluation Result - EVOH Shutdown and Purge Test Purge Resin MFI (g/10min, at 190 C) Die Buildup (gm) Final gel level (Number/m 2 ) Average gel level (Number/m 2 ) Total gels during 3 hrs extrusion ETC ,556 LDPE 0.25 MI ,205 HDPE 5.0 MI ,740 The evaluation results of the EVOH shutdown and Purge Test are shown graphically in Figures 1 through 3. 2

3 Figure 1. Gels/ sq. meter Purge: ETC Hour EVOH extrusion Figure 2. Gels/ sq. meter Purge: LDPE 0.25 MI 3 Hour EVOH extrusion Figure Purge: HDPE 5 MI 3 Hour EVOH extrusion 3

4 The table below shows the evaluation result for the EVOH to nylon Transition Purging test. Purge MFI (g/10min at 190 C) Gels/2.4 m 2 Last 250m Nylon Average gels/2.4 m 2 During 2500m Nylon 60 min LDPE purge min ETC-103 purge min purge + shutdown ETC Commercial Purge A Note: Average number of gels in nylon film run on a clean die was 35 gels / 2.4 square meters. The figure below graphically shows the results of the EVOH to nylon transition test. ETC-103 showed the best results in the test. EVOH to Nylon Transition Test ETC-103 Purge ETC-103 Purge and Shutdown Purge A LDPE Purge Average Number of gels / 2.4 sq. meters Nylon film 4

5 Purging Procedures Shutdown Procedure with ETC Introduce ETC-103 into extruder running EVOH at normal conditions. Fill extruder and downstream equipment with ETC-103. (Depending on machine volume 25~50 lbs. is usually required) 2. Reduce extruder temperatures and follow normal shutdown procedure. Leave ETC-103 in extruder until ready to restart line. 3. When restarting machine, leave ETC-103 in extruder until ready to begin introducing EVOH. Purge out ETC-103 with normal EVOH grade and resume production. Intermediate purge resins are NOT required. Short Stop/Transition Procedure with ETC-103 When a transition to another material (Nylon, PE, PP etc) is required or a full purge to clean up extrusion system before continuing to run EVOH is needed, the following procedure is recommended. 1. Introduce ETC-103 into extruder running EVOH at normal conditions. Purge at low speed for 5 minutes, gradually raise speed to higher rpm. (Cycling rpm will improve purge effectiveness) 2. If changing over to a new material, raise temperatures to new running conditions (for lower temperature materials raise temperatures 20~40 degrees until Step 3. is over). Continue purging until temperatures have stabilized or for 30 minutes. 3. Stop extruder, change screens and wait for 15~30 minutes. 4. Restart extruder; check running conditions and cycle rpm until melt is clean. 5. Slow extruder to low rpm and introduce new material or EVOH immediately behind ETC Purge in new material or EVOH and follow normal startup procedures. A final high-speed purge will reduce time required before normal production can restart. Running Purges A short running purge can be conducted to clean up EVOH extruders on the fly during long production campaigns. 1. Introduce ETC-103 into extruder running EVOH at low rpm. Purge in at low rpm and then cycle rpm from low to high for 15~30 minutes. 2. Purge out ETC-103 with normal EVOH with a high/low rpm cycle. Resume normal production when melt is clean. These procedures are intended only as general guidelines for the use of ETC-103. Adjustments may be made to this procedure to match existing practices and equipment. To place an order for EVAL resins, obtain technical assistance or discuss your packaging needs, please contact EVAL Company of America, 2625 Bay Area Blvd, Suite 300, Houston, Texas 77058, phone

6 The information contained herein is, to the best of our knowledge, true and accurate. However, since conditions of use are beyond our control, all recommendations or suggestions are presented without guarantee or responsibility on our part. We disclaim all liability in connection with the use of information contained herein or otherwise. All risks of such use are assumed by the user. Furthermore, nothing contained herein shall be construed as an inducement to use any process or to manufacture or use any product in conflict with existing or future patents. 6