Paint & Coatings Industry - April 2008 - (Page 33)

Fiber Applications Acrylate Coatings As a class, acrylate coatings tend to outperform other chemistries for cost, ease of processing, cure speed and commercial availability. Silicones and polyimides are typically slower curing, in many cases are solventborne, and often are incompatible with other components in the liquid form. The purpose of this paper is to present some of the work conducted to maximize the operating temperature range of acrylate coatings in these types of applications. As part of this work, six outer or “secondary” coatings for optical fiber were tested for changes in weight loss, FIGURE 1 | Secondary coating weight loss after 24 hours at various temperatures. 40.00 35.00 Weight Loss (%) 30.00 25.00 20.00 15.00 10.00 5.00 0.00 SC-1 SC-2 SC-3 SC-4 SC-5 225°C 175°C 125°C SC-6 as much of the typical communications-grade fiber is rated at below 100 °C operating temperature. The bare silica glass in downhole optical fibers is typically sealed with a carbon or hermetic coating that is extremely resistant to hydrogen migration. On top of this hermetic coating, different chemistries are used that dramatically influence the final operating temperature of the fiber. Typically, acrylate coatings are used for applications from 85 to 150 °C. From 150 to 200 °C, silicones and fluorinated materials such as PFA (tetrafluoroethylene perfluoroalkylvinylether copolymer) are used, and, for applications demanding 200-300 °C, a polyimide coating is used.3-5 In these sensor applications, as well as in more typical telecommunication environments, the coating will preferably be strippable from the underlying glass in order to splice, or connect, to other optical fibers or directly to instrumentation. The ease with which the stripping can be performed is a key factor in how practical they are to use in the field. Acrylate coatings typically can be stripped by mechanical methods either at ambient temperature or by using a heated tool. One issue with using the more heat-resistant chemistries is the difficulty in removing them from the fiber. For instance, polyimide coatings often require a very strong acid in order to achieve removal. This is time consuming and involves special handling techniques. FIGURE 2 | Secondary coating weight loss vs. exposure time at 225 °C. 40.00 35.00 Weight Loss (%) 30.00 25.00 20.00 15.00 10.00 5.00 0.00 SC-1 SC-2 SC-3 SC-4 SC-5 24 Hr 2 Hr 1 Hr SC-6 33 PA I N T & C O A T I N G S I N D U S T R Y

Table of Contents Feed for the Digital Edition of Paint & Coatings Industry - April 2008

Paint & Coatings Industry - April 2008 Contents Viewpoint Industry News Calendar of Events Company News Mergers and Acquisitions Names in the News Snapshots of Success – Automotive Applications Designing UV-Curable Materials for High-Temperature Optical Fiber Applications The Future of UV Coatings is Now! Milling Media Review Part 1 – Bead Density Effect Preparation and Properties of UV-Curable Polyurethane Acrylate Resins for Metal Surfaces Conquering Color Harmony High-Performance PU Crosslinkers for Two-Component Waterborne Applications Decorative Film Laminates How Long Will the Gilding Glitter? Gaining a Competitive Advantage Using Benchmarking Supplier Showcase Materials Watch Products and Literature Classifieds Advertiser Index Automotive Color Trends New England Museum Solves Century-Old Vanderbilt Mansion Mystery

Paint & Coatings Industry - April 2008

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