MARINELINE® & CHEMLINE® COATINGS FOR INDUSTRY

APC Independent Tests - Part 2

An Independent Technical Report on the Suitability of MarineLine® for Cargo Tank Coatings - By Anticorrosion Service - del dott. Norbert Ackermann
 

CHEMICAL RESISTANCE

In order to test the chemical resistance of the coating system applied and heat cured five glass jars with cut-off bottoms were glued by means of a high resistance epoxy adhesive to the horizontal surface. The epoxy adhesive was left to cure for six days and then the jars were filled with 250 cm3 of the following chemicals:

1.  Sulfuric acid 98%
2.  Hydrochloric acid 37%
3.  Methanol (methyl alcohol)
4.  Methylene chloride (dichloromethane)
5.  Cellosolve solvent (monomethyl ethylene glycol ether).
TESTING    
Pull testing. Testing 98% sulfuric acid MarineLine exhibits high adhesive strength.
Testing 37% hydrochloric acid. Testing methylene chloride. Testing cellosolve.

The resistance tests lasted 14 days for the acids and 22 days for the solvents. Fresh water was added to the methanol after 22 days in order to test the coating resistance against blistering. The coating areas in contact with the chemicals performed as reported below.

1.  Sulfuric acid 98%. No softening, swelling or chalking. Coating surface slightly matted showing some pink stains. High resistance epoxy coatings disintegrate within a few days in 98% sulfuric acid.
2.   Hydrochloric acid 37%. No softening, swelling or chalking. Coating surface still glossy but the colour had changed to ruby red.

3.   Methanol. No softening, swelling, chalking. Coating surface still glossy. No blistering after one week of subsequent water immersion. High resistance epoxy coatings usually suffer blistering if subjected to methanol/water immersion.
4.   Methylene chloride. No softening, swelling or chalking. Coating surface still glossy. High resistance epoxy coatings suffer softening, swelling and peeling within one week in methylene chloride.
5.  Cellosolve solvent. No softening, swelling or chalking. Coating surface still glossy.


Testing methanol.

 

The test results comply with the resistance list provided by APC and confirm also that the heat curing was carried out properly. The only anomalies found were the colour change in hydrochloric acid and the slight staining in sulfuric acid. According to APC, these phenomena may be avoided if the heat curing is carried out at 125° C, but this assertion has to be verified.

The lack of softening and/or swelling of the coating indicates low absorption values. Absorption data given by APC are indeed very low if compared to epoxy coatings:

MARINELINE EPOXY
(1) (1)
Sulfuric acid 0.07% disintegrated
Methylene chloride 0.02% disintegrated
MEK 0.01% 7.2%
NaOH 0.01% 1.1%
NaOCI 0.00% 1.6%
(1) Percentage weight increase
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