PLA aims at food bottles plus labels & caps. (Keeping Up With Blow Molding).Cargill Dow LLC (Logical Link Control) See "LANs" under data link protocol. LLC - Logical Link Control , Minnetonka, Minn., is developing stretch-blow molded food bottles with labels and caps all based on the company's Nature Works polylactic acid polylactic acid /poly·lac·tic ac·id/ (-lak´tik) a hydrophobic hydroxy acid polymer that is formed into granules and used as a surgical dressing for dental extraction sites. (PLA (Programmable Logic Array) A type of programmable logic chip (PLD) that contained arrays of programmable AND and OR gates. PLAs are no longer used. See PLD. (language, music) Pla - A high-level music programming language, written in SAIL. ) resin. The first commercial applications for PLA bottles and labels (but not yet caps) are expected in Europe early next year. They'll be used for dairy drinks and edible oils with a short (5-10 day) shelf life. "A natural product in a natural package" is the attraction of PLA bottle systems. PLA is derived from bacterial fermentation of cornstarch cornstarch, material made by pulverizing the ground, dried residue of corn grains after preparatory soaking and the removal of the embryo and the outer covering. It is used as laundry starch, in sizing paper, in making adhesives, and in cooking. and biodegrades when composted. The company's stretch-blow molding grade is Nature-Works PLA 700D. "PLA retains its clarity and physical properties under stretch," says Kevin Cink, applications engineer at Cargill Dow. He says PLA's melt strength is not adequate for extrusion blow molding. In stretch-blow, however, PLA'S melting point of 215 F vs. PETs 275 F permits energy savings. However, PLA's moisture-vapor transmission rate (MVTR MVTR Moisture Vapor Transmission Rate MVTR Multi-Stage Vacuum Tube Receiver MVTR Mobile Videotape Recorder ) is at least 10 times higher than PETs, which imposes limits on shelf life for PLA applications. Loss of water from a sealed PLA bottle could be significant enough over time to cause buckling of the container. Bob Springs, Cargill Dow Europe's managing director, says edible oils are an initial target for PLA because they contain no water. Dairy drinks are another because they are refrigerated re·frig·er·ate tr.v. re·frig·er·at·ed, re·frig·er·at·ing, re·frig·er·ates 1. To cool or chill (a substance). 2. To preserve (food) by chilling. , which greatly reduces moisture loss. Cargill Dow is assessing barrier coatings and barrier-resin coinjection to overcome PLA's inherently weak moisture and gas barrier. Meanwhile, Cargill Dow's film-grade PLAs are suitable for biaxially oriented film labels, including pressure-sensitive types, wrap-around stretch sleeves, and paper laminates. However, PLA closures are a challenge. PLA does not readily lend itself to injection molding of complex closures--e.g., ones with tamper-evident bands--and it also tends to break when twisted. One promising solution is blending PLA with more ductile biodegradable copolyesters like those supplied by Eastman Chemical and BASF BASF Bar Association of San Francisco (since 1872; San Francisco, California) BASF Badische Anilin und Soda Fabrik (German chemical products company) BASF Builders Association of South Florida . Cargill Dow: (877) 423-7659, www.cdpoly.com |
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