Alternatives to biocides:Downstream users perspectives
A.I.S.E./CEPE workshop. 15 May, 2019Jan Lorenzen, Danish Technological Institute
[email protected], +45-7220 1836
Contamination of paint
• An on-going challenge→ DK EPA projects
0
50
100
150
200
250
300
350
400
450
Jan Mar Maj Jul Sep Nov Jan Mar Maj Jul Sep Nov
Rel
ativ
e n
um
ber
of
com
pla
ints
p
er m
on
th (
Jan
uar
y ye
ar 1
=
ind
ex 1
00
)
Registered claims for contaminated paint
Why do we need in-can preservation?
• Bacteria can grow in paint• Water, organic carbon, nutrients
• Bacteria will enter paint• In raw materials
• During production
• During use
Production & contamination
• Routine & special microbiological control
• Linking production to contaminated paint
Production Bacterium
Filling station Stenotrophomonas sp.
Filter Stenotrophomonas sp.
Filter Pseudomonas sp.
Filter Citrobacter sp.
Filter Acinetobacter sp.
Filter Pseudomonas sp.
Paint Bacterium
A Enterococcus sp.
B Pseudomonas sp.
C Pseudomonas sp.
E Pseudomonas sp.
F Citrobacter sp.
G Pseudomonas sp.
Paint development
• Raw materials contain microbes & sustain microbial growth
• Components interact with biocides
New paint
• Raw material selection can improve preservationRaw material Score
Talc 1 1.3
Talc 2 1.8
Talc 3 2.0
Talc 4 2.3
Talc 5 4.0
CaCO3 1 0.0
Type Function
SiO2 A Filler
Dolomite A Filler
CaCO3 C Filler
Co-polymer A Antifoam agent
Thickener E Anionic thickener
Dispersion Agent C Non-ionic dispersant
Recipe Score
Standard 81-014 2.6
Test 81-013 2.1
Test 81-012 1.8
Improving biocide effect
Positive control
Biocide alone
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
amine caprylyl glycol exyl hexyl glycerin caprylyl lactate
Gro
wth
(lo
g (a
bs e
nd/a
bs s
tart
))
ingredient alone ingredient w/ biocide
High pH
• Silicate paint w/ high pH
• Unpreserved interior white matt wall paint w/o added bacteria• Not a universal solution
0
10
20
30
40
50
7.5 8.2 8.9 9.5 10.4 11.4
She
lf li
fe (
day
s)
pH
Influence of pH on shelf life of unpreserved paint
Non-biocide preservation
• Pasteurisation → destroys paint
• Adding salts → poor quality paint
• High solid paint → poor quality paint
• High pH → only matt paint
• No water → powder paint
10 % 20 % 30 % 40 % 50 %
60 % 70 % 80 % 90 % 100 %
Conclusions
• Paint allows bacterial growth
• Reduce microbial load• Raw materials & paint formulation & production hygiene
• Improve biocide effect• Paint formulation?
We cannot do without residual biocide effect in-can
Housekeeping &
formulation
Biocide
Acknowledgements• Flügger A/S
• Søren Poulsen, Simon Lynge Hansen, Michael Bromberg, Lars Find Andersen, Jane Faltum
• Danish Technological Institute• Jeanette Schjøth-Eskesen, Michael Vedel Wegner Kofoed, Berit Lindegaard, Jacob Ask Hansen, Yijuan Xu,
Peter Lüttge Jordal
• Financial support: • Reducing biocide concentrations for preservation of water-based paints
• Environmentally friendly production of water-based paint