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64
Jan/Fev 2012
PAINT & PINTURA
Table 1. White Primer Cure Rate & Film Hardness Development Comparison*
Cure Properties
Solvent-borne Primer
NewGen White Primer
Set to Touch
0.5
0.25
Cotton Free
7.5
2.0
Thru Dry
10.5
3.5
1 Day Pencil Hardness
<6B
F
1 Week Pen. Hardness
2B
F
Cross Hatch Adhesion*
5A
5A
MEK Double Rubs*
>200
132
Salt Fog Resistance (888 hrs)
Undercutting/Rust, mm
Blisters @ Scribe (field)
3 / 2
6F
0 / 0.5
None
* 2.5 – 2.7 mils DFT after 7 Days cure at 25°C and 55% Relative Humidity on cold rolled steel
Table 2. Gloss White Enamel Property Comparison*
White Enamel Property
Solvent-borne
NewGen
Through Dry; Hours
8.5
6.0
Pencil Hardness ( 1 day / 1 week)
4B / H
5B / F
Gloss per cent ( 60° / 20°)
95 / 87
102 / 90
Impact Resistance ( dir / rev inch-lb.)
160 / 160
160 / 160
MEK double rubs*
337
308
25°C Water Immersion; days
Blister Rating, field*
>250
10 (none)
>250
10 (none)
Salt spray resistance; hours
Blister rating, field*
1152
6F – 6M
1152
10 (none)
* 2.5 – 2.7 mils DFT after 14 Days cure at 25°C and 55% Relative Humidity on cold rolled steel
Conclusões
Nos últimos 30 anos, a Momentive
Specialty Chemicals desenvolveu
várias gerações de sistemas epóxi
waterborne (resina mais endurece-
dor). Informações adicionais sobre
a formulação destes sistemas estã
disponíveis no site
inlcusive estas com base no
novo sistema da nova geração 2K
waterborne epoxy
4
que fornece às
tintas:
Melhor compatibilidade e coales-
cência;
Tendência reduzida para formar
bush por excesso de amina;
Melhor desempenho com secagem
mais rápida e maior dureza, com
resistência superior à corrosão e
química, e níveis de VOC menores
que 100g /l
Referências
Elmore, J, et al, Waterborne Protec-
tive Coatings for Metal; Journal of
Coatings Technology, Vol. 74, No.
932, August 2002; pp 63-72.
Weinmann, D. J., et. al. (2001) “For-
mulating Water-borne Epoxy Coat-
ings”, 44
th
Annual Technical Sympo-
sium; Water-borne Coatings: Sink
or Swim, May 17-18, 2001, Cleve-
land, Ohio. Sponsored jointly by the
Cleveland Society for Coatings Tech.
and the Pittsburgh Society for Coat-
ings Tech.
Please see “Starting Formulations
from Momentive Specialty Chemi-
cals” products web site
Momentive’s NewGen waterborne
system is EPI-REZ Resin 6520-WH-
53 combined with
EPIKURE Curing Agent 6870-W-53.