Page 48 - Market Analysis Report of Optical Communications Field in China & Global market 2018

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Cure Speed Measurements of UV-LED Curable

Optical Fiber Coatings

Xiaosong Wu, Kenneth Thomas, Tess Ho
DSM Functional Materials
A bstract Table 1. UV-LED Conversion Status

Thanks to its tremendous energy saving potential, UV-LED cure is
rapidly gaining popularity in optical fiber manufacturing. In addition,
to meet ever growing demands, many manufacturers are making efforts
to increase draw speed. Therefore, there is a need to develop cure speed
tests in the laboratory to characterize optical fiber coatings, to ensure
they have sufficient cure response to UV-LED light sources. In this paper,
preliminary results of such tests are reported.
Keywords: Optical fiber coatings, UV-LED, cure speed, oxygen
inhibition, photo-DSC, real-time FTIR, ATR. been catching up in recent years.

1.Introduction Due to the combination of relatively lower intensity and longer
In the past decade, UV-LED cure has begun to revolutionize the wavelength (Figure 3), UV-LED cure is more susceptible to oxygen
radiation cure industry, with many distinct advantages over traditional inhibition than conventional UV lamps, Figure 3. There have been
and established UV arc or microwave curing technologies. numerous publications [4][5][6][7] to address such challenges in
Figure 1. Comparison – Conventional UV vs UV-LED [1] recent years. With the technical know-how, including mitigating oxygen
inhibition, UV-LED curable coatings have been formulated to support
the industry-wide adoption that is currently taking place.
Figure 3. Emission Spectra, Mercury Lamp vs LED lamp [8]

In recent years, industry wide conversion to UV-LED is gaining It’s been reported [9] that more than 80 % energy savings have been
momentum, primarily due to its tremendous energy savings over realized in actual fiber manufacturing with good fiber properties.
traditional broadband UV technologies, as well as its environmental-
friendly nature. Another study [10] revealed various cure efficiencies with several UV-
LED lamps from industry-leading suppliers.
Many governments are joining forces to promote energy efficiency
for environmental protection purposes. One example is the recently Another prevailing trend in optical fiber manufacturing is the pursuit of
announced “Green Manufacturing” initiative by China in its 13th 5- high draw speed to meet the continuously growing global demand. With
year plan for economic and social development [2], outlining ambitious draw speeds of only 25 m/min [11] in the beginning of the industry
goals toward environmental protection by manufacturing practices that in early 1970s, to the current reported processing speeds of up to 2500
are more energy efficient, with less hazardous emissions and/or reduced m/min and structure speeds of 3000 m/min [12], the increase of draw
waste to the environment. speed has been phenomenal and will continue.
While many radiation cure applications are in the process of converting 2.Experiments
to UV-LED technology, the optical fiber manufacturing industry has 2.1 Coating samples
Figure 2. Green Manufacturing initiative [3]
Table 2 listed the three secondary coating samples that are evaluated
in this paper.

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