Alternatives to biocides:Downstream users perspectives

A.I.S.E./CEPE workshop. 15 May, 2019Jan Lorenzen, Danish Technological Institute

jnl@dti.dk, +45-7220 1836

Contamination of paint

• An on-going challenge→ DK EPA projects

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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.

Factory hygiene

• Hot spot localisation

• Improvement of cleaning and cleanabilityYear 1

Year 2

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

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High pH

• Silicate paint w/ high pH

• Unpreserved interior white matt wall paint w/o added bacteria• Not a universal solution

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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

Thank you!

Jan Lorenzen, jnl@dti.dk, +45 7220 1836