Injection blow molding COC arrives: here's how to do it. (Blow Molding Close-Up).* Cyclic olefin copolymers Cyclic Olefin Copolymer (COC) is an amorphous polymer made by several polymer manufacturers. COC is a relatively new class of polymers when compared to polypropylene and polyethylene. , or COCs, are a new family of amorphous engineering thermoplastics with high clarity moisture barrier, HDT HDT Heat Deflection Temperature (plastics) HDT High Dose Therapy HDT Heatpipe Direct Touch (Xigmatek) HDT Heat Distortion Temperature (plastics) HDT Henry David Thoreau , and chemical resistance. Their first commercial injection-blow molded applications are just now beginning to appear on the market. Topas COCs from Ticona are being used to make drug and medical bottles that can withstand all the usual sterilization sterilization Any surgical procedure intended to end fertility permanently (see contraception). Such operations remove or interrupt the anatomical pathways through which the cells involved in fertilization travel (see reproductive system). methods--steam, ethylene oxide ethylene oxide Occupational medicine A gas used to sterilize medical supplies and other materials , and electron and gamma radiation gamma radiation, high-energy photons emitted as one of the three types of radiation resulting from natural radioactivity. It is the most energetic form of electromagnetic radiation, with a very short wavelength (high frequency). . Bottle sizes generally range from 20 to 40 cc, with typical wall thicknesses of 0.05 to 0.06 in. Topas COC See chip on chip. has also been stretch-blow molded, resulting in moderately improved mechanical properties. Molding tips Since most processors are unfamiliar with these materials, Ticona's technical experts provided PLASTICS TECHNOLOGY with basic recommendations for injection-blow molding a range of Topas grades. The injection molding injection molding n. A manufacturing process for forming objects, as of plastic or metal, by heating the molding material to a fluid state and injecting it into a mold. portion of this process involves conditions similar to those recommended for plain injection molding of COCs (see accompanying tables and PT, Nov. '02, p. 62 for more on injection molding COC). In the blow molding step, temperatures should be 54[degrees] F above the resin's glass-transition point, and air pressure should be between 75 and 150 psi. Cycle time is usually 10 sec from injection to strip. Undercuts at the neck should be as small as possible, Ticona advises, though minimizing undercuts involves balancing the need to keep the bottle on the machine during the process against the need to remove the finished bottle without cracking it. Bottles should be handled carefully while warm to prevent marring their surfaces. If halos and rings show up on bottoms of bottles, they can be eliminated by cleaning the core rods and reducing the bottom temperature. If bubbles appear, reduce screw speed and increase backpressure back·pres·sure n. Residual pressure opposing the free flow of a gas or liquid, as in a pipe or an exhaust system. . If voids occur, decrease cure time. Black specks can be eliminated by cleaning the manifold and lowering nozzle temperature. If neck cracking occurs, reduce the size of the undercut on the stripper Stripper Slang for an individual homeowner who strips the equity out of his or her home through mortgage refinancing. Proceeds are generally not re-invested, but spent on consumer goods. Notes: Most people get rich by saving and investing wisely. plate. Injection-blow molding recommendations were provided by Ticona's Ron Lamonte, development associate; Doug Hammond Doug Hammond (born December 26, 1942) is a free funk/avant-garde jazz drummer, professor, composer, poet and producer from Tampa, Florida, U.S.A. His first major release was Reflections In The Sea Of Nurnen on Tribe Records. , business development engineer; Donal McNally, product marketing manager; and Ken Music, technical service engineer. Mr. Music passed away quite recently. In addition to being a Ticona engineer, he was an emergency medical technician e·mer·gen·cy medical technician n. Abbr. EMT A person trained and certified to appraise and initiate the administration of emergency care for victims of trauma or acute illness before or during transportation of victims to a health care and spent weeks at Ground Zero in N.Y.C. helping others after the 9/11/01 attacks. INJECTION-BLOW MOLDING COCs (TYPICAL START-UP CONDITIONS) Topas Grade 8007-D61 6013-D61 6015-D61 MFR, g/10 min 30 13 4 HDT, F @ 66 psi 167 266 302 Cylinder Temp., F Feed! <140 <230 <230 Barrel Zone 1 374-428 446-500 464-518 Barrel Zone 2 392-446 464-518 482-554 Barrel Zone 3 392-446 464-518 482-554 Barrel Zone 4 392-446 464-518 482-590 Nozzle 392-500 464-572 446-590 Mold Temp., F Preform 122-158 212-230 212-266 Neck 122-150 194-212 212-230 Body 122-158 212-266 266-302 Bottom 130-158 212-230 284-320 Blowing 122-158 194-212 212-230 Stretching * 212-248 320-356 356-392 Melt Temp., F 374-446 464-518 500-554 * Stretch-blowing only MACHINE SETTINGS Injection Pressure, psi 7255-14,510 Hold Pressure, psi 4353-7255 Backpressure, psi 10-30 Injection Speed, mm/sec 50-150 (0.5 to 2 sec) Screw Speed, rpm 100-150 Screw Suck-Back None or minimal Cushion Small (4 mm typical) Screw Type PVC type (long L/D) Nozzle Type Free-flow Nozzle ID, mm 0.9-2.2 Draw Ratio 1:2 to 1:3 (stretch-blow) Gate Diam., mm 1.8-2.2 NEED TO KNOW MORE? Ticona, Summit, N.J. (800) 833-4882, www.ticona-us.com |
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