Silicone Lubricant Injection

An example of liquid injection which gives both technical advantages and economic savings is a special application in which a silicone lubricant is incorporated at a level of 2% during the extrusion of small bore HOPE tubing. The purpose of the silicone is to provide a very low coefficient of friction. 

The tube is extruded to high tolerances with continuous laser monitoring. The addition of liquid silicone at the hopper would make it difficult to keep within tolerances, whilst silicone masterbatch would be expensive and may also give dimensional problems. 

By direct injection into a CTM added to the extruder, the required level of silicone is incorporated into the HOPE with no dimensional tolerance compromises and economic savings are made by purchasing the silicone in 25 kg drums instead of using a masterbatch. 

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C. D. Porter, "Evaluation of a Silicone Lubricant Injected Spinally", Toxicol. Appl. Pharmacol. 15, 566-573 (1969). 

Because of their chemical inertness, low surface tension and antisurfactant activity polyorganosiloxane (silicone) oils have found varied applications in medicine. These have included use as an artificial lubricant for arthritic joints191, as a means of soft tissue augmentation, and as an additive in creams and oils for burn treatment. Di-methylpolysiloxane fluids have been injected as replacement for aqueous and vitreous humour in eyes. Reactive organosilicon compounds comprise a new class of potential prophylactic and therapeutic agents192. Protection against atherosclerosis... 

Removal of the article from the mold is lengthy process because anti-adhesive lubricants have to be sprayed on the on a mold surface before every injection, in an operation that takes up to 25 - 30% of the full cycle. In reactive molding of polyurethane-based compounds, internal lubricants are used in combination with surface coatings. This allows us to remove articles from a mold many times with a single coating treatment. One of the compounds used as an internal lubricant is silicon-organic liquids. 

Ready to Sterilize (RtS) Typically components are washed, then rinsed with Water For Injection (WFI) to reduce bioburden and endotoxin levels, lubricated with silicone oil, and finally packaged in a classified area (Classes 100-10,000) in Tyvek bags that can be steam sterilized by the drug or device manufacturer before use. Alternately polyethylene bags may be used if the end user is utilizing gamma radiation for sterilization. 

The method involving the Mo-V-P acid has been used in determinations of phosphorus in biological tissues [127], plant material [128], fruits [129], fish products [130], foodstuffs [131], phosphate minerals [132], cast iron and steel [133,134], niobium, zirconium and its alloys, titanium and tungsten, aluminium, copper, and white metal [135], nickel alloys [134,135], metallurgy products [136], molybdenum concentrates [137], silicon tetrachloride [7], cement [138], and lubricants[139]. The flow injection technique has been applied for determining phosphate in minerals [140] and in plant materials [141]. 

RTP produces series of engineering thermoplastics lubricated with PTFE, molybdenum disulfide, graphite powder, silicone and glass, carbon and aramid fibers. Grades AR, TEE and SI include respectively aramid fibers, PTFE (10-20%) and silicone fluid (0.5%). Matrix materials used include PA-6, PA-66, PA-6,10, PA-12, PC, POM, PET, PBT, PSF, PPS, PEI, PEEK and polyphthalamide. The blends have been developed for injection molding of various parts for engineering applications. 

Processing aids to assist material flow during extrusion or injection molding. The internal and external lubricants are recognized. Internally lubricated resins use oils. Teflon , M0S2, or other materials to give the molded part a lower coefficient of friction. The external lubricant can be a sohd, such as sodium or zinc stearate, a fluoropolymer, or silicone resin or liquid. 

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