Page 28 - 201902 SCA February 2019 Volume 56 Number 1

Technical ARTICLE Studies of pre-treatment in various woods with high
performance light stabilizers

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Screening Design of Different Type of Woods and (X2-1: Top Coat: Waterborne Acrylic Resin, X2-2:
Co-solvents by using EV-AQ and EV-SB Wood Pretreatment: Butyl Carbitol mixed with EV-
Screening design (Table 7) was used to identify SB, Top Coat: EV-AQ mixed with Acrylic Resin and
factors that get the minimal color change after X2-3: Wood Pretreatment: IPA mixed with EV-SB, Top
weathering test. Mathematical model derived from Coat: EV-AQ mixed with Acrylic Resin). The Analysis
data indicates all factors –X1: 5 different type of of variance, parameter estimates and effect tests are
woods (Cedar, Douglas fir, Southern beech, African shown in Table 8, Table 9 and Table 10.
Teak and Southern pine). X2: 3 type of treatments
The Optimal Prediction Profiler
The prediction profiler (for example, Southern
pine) shows the effect of 3 types of treatment after
weathering test for 300 hrs. For the item which
uses waterborne acrylic resin only, the yellowing
after weathering test is significant. (color difference
ΔE=31.85) (as shown in Figure 4, page 28). 10% EV-
SB is mixed with Butyl Carbitol in the pretreatment
and 2% EV-AQ in top coat. The performance is
better than the Blank (color difference ΔE=10.25) (as
shown in Figure 5, page 28). The 10% EV-SB mixed
with IPA in the pretreatment and 2% EV-AQ in top
coat. The light fastness of Southern Pine is the best.
(color difference ΔE=6.55) (as shown in Figure 6,
page 29). The photos of different type woods after
weathering test are shown in Figures 7 to 11 (see
page 30).

RESULTS
After weathering test, the result shows that the
mixture of Eversorb® SB and Eversorb® AQ can
significantly protect wood surfaces from yellowing. In
addition, Eversorb® SB mixed with isopropyl alcohol
can provide better performance than Eversorb® SB
mixed with butyl carbitol.
CONCLUSION
Environmentally friendly coatings are the trend for
future development. We have developed several
unique products specifically for coatings.
Eversorb® AQ, a blend of UV absorber and HALS,
is developed for waterborne clear coats. Eversorb®
SB, designed for wood pretreatments, can protect
lignin from UV light degradation.

Lignin is a complex organic polymer containing
hydroxyl functional groups (-OH). The solubility
parameters of isopropyl alcohol and butyl carbitol
are 11.5 and 9.9, respectively. After weathering test,
the result shows Eversorb® SB can provide better

26 Journal of Surface Coatings Australia • February 2019