WCA March 2024

Technical Article

4. Conclusions This work demonstrates materials technologies for laser printing of fibre optic cable jacket compounds. The impact of laser-marking additives, resin and printing conditions on mark contrast are discussed. Accelerated weathering performance and enhanced abrasion resistance are demonstrated on a fully formulated compound. These developments will enable laser printing, with fine mark contrast, on down-gauged cable designs to meet the needs of evolving trends in communications infrastructure. 5. Acknowledgements The authors would like to thank the many contributors in the labs of The Dow Chemical Company. 6. References [1] L. Santo, F. Trovalusci, J.P. Davim. “Laser Applications in the Field of Plastics”, Comprehensive Materials Processing 2014, 243-260 [2] P.J. Brigandi, S.A. Saba, M. Esseghir, T. Geussens, T. Hogan, R. Anderson. “Development of Material Solutions for 5G and Dense Fiber Networks”, 70 th IWCS, Proceedings of the International Wire & Cable Symposium (IWCS), Inc (2021) [3] S.P.K. Meruva. “Laser Writable Polymers: Markability and Durability Characteristics”, 2008 Napier University, PhD thesis [4] S. Sabreen. “New Technologies for High Speed Color Laser Marking of Plastics”, 2004 Plastics Decorating [5] J. Yu, M. Esseghir, T. Geussens. “New Jacketing Technology for High Speed Laser Marking of Fiber Optic Cables”, Advanced Cable North America, March 18-20, 2019, Charlotte NC [6] Y.M. Noor, S.C. Tam, L.E.N. Lim, S. Jana. “A Review of the Nd:YAG Laser Marking of Plastic and Ceramic IC Packages”, J. Mater. Process. Technol. 1994, 42 (1), 95-133 [7] V.T. Wallder, W.J. Clarke, J.B. DeCoste, J.B. Howard. “Weathering Studies on Polyethylene Wire and Cable Applications”, 1950 Ind. Eng. Chem. 2320-2325.

printable; however, the MDPE-based solution achieves greater contrast over a range of conditions at higher print speeds, whereas the HDPE-based solution achieves greater contrast at the lower print speed. This data suggests that crystallinity also affects energy dissipation from the laser. 3.3 UV stability Fibre optic cables are exposed to a variety of environmental conditions and used in both indoor and outdoor applications. In particular, for outdoor applications long-term UV stability is desirable. Accelerated weathering tests have been developed for wire and cable applications. [7] In the QUV accelerated weathering test, a minimum of 50% retention of elongation at break is required after exposure. Laser-printable jacket compounds, with less than the standard 2.3% carbon black, need to contain the appropriate UV stabilisers to meet this standard. Therefore, a fully formulated solution was optimised for both laser printing and long-term UV stability. Figure 5 shows elongation at break of un-aged and 4,000h QUV aged samples. Both the formulated laser-printable compound and the control compound with 2.5% carbon black well exceed the industry requirement of 50% elongation at break retention after ageing.

Figure 5 : Elongation at break comparing un-aged and 4,000h QUV-aged materials. The dashed line shows the specification for 50% retention

3.4 Abrasion resistance For cables being installed into ducts, durability of identifying marks is critical for the cable installation process. In comparison to laser marking, ink marks can be easily removed with organic solvents, can have adhesion issues to some polymer substrates, and involve the use of hazardous materials in inks. Here we evaluated the durability of laser marks using a Taber Abrasion test. Figure 6 shows that after 100 cycles of abrasion with sandpaper the laser marks are still clearly visible and have excellent durability to mechanical abrasions. By comparison, the ink marks were removed after ten abrasion cycles, thereby demonstrating the superior durability of laser marking for jacket compounds.

Courtesy of IWCS Cable & Connectivity Forum

The Dow Chemical Company 400 Arcola Road, Collegeville, PA 19426 USA

Tel: +1 610 244 6052 Email: sasaba@dow.com Website: www.dow.com

Figure 6 : Photograph of laser marks (a) before and (b) after 100 cycles of abrasion

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March 2024