Background: Van Horn Metz requested that we prepare and test latex coatings from several manufacturers with and without Buckman Laboratories pigment. Butrol 23, a calcium modified barium metaborate, will be used in this study with waterborne latices. Our additives will then be evaluated in the coatings containing no Butrol 23. Typical coating formulations could then be prepared for our distributors.
Purpose: Compare Cortecs additives against Butrol 23 from Buckman Labs. Prepare typical formulations with our additives.
Materials: Cortec M-119 modified (98% M-119 + 2% M-326)
Cortec M-118exp. (71% EXP-391+29% M-119)
Butrol 23 (Calcium modified barium metaborate)
Rohm and Haas, PR71, latex
Eastman, Aquamac 715, latex
NeoCryl XA-6109, latex
NeoCryl A-639, latex
Setalux 373372, Akzo, latex
Draw down bar
Methods: Salt spray test: ASTM B-117
Humidity test: ASTM D-1748
Procedure: Five latices were selected to evaluate with Butrol 23 and with Cortec additives. A control formulation with Butrol 23 was prepared with each latex. A blank formulation was then prepared containing no Butrol 23. This formulation would be used to post add Cortecs additives. The additives tested in each latex were as follows:
These coatings would then be tested for gloss, salt spray resistance, and humidity resistance. The best formulations would then be published for our distributors to show the advantages of Cortecs additives.
Discussion: Butrol 23 is a modified barium metaborate pigment, which is not only toxic, but is very difficult to disperse. The recommended level of Butrol 23 is 100lbs. /100Gal. The level used in the formulations studied here is only 80# since it was difficult to disperse the Butrol 23. All studied formulations presented in the attachment.
This study represents only waterborne coatings and additives. Another project is planned in which solvent-based coatings will be evaluated with Cortec's additives.
Rohm & Haas PR-71 latex:
Formulation #1 with 3.3% Butrol / 2.3 M-119 (modified with RM-326) had the best salt spray and humidity resistance of all samples tested. See Table I. The advantages of using the combination of Butrol 23 and M-119 are as follows:
See Figure 1 and Formulations 1 and 2 (Attachment).
The blank sample with no additives was as good as any of the other additive systems including Butrol 23. See Table I. Additional testing at considerably longer exposures in the salt spray chamber and humidity chamber may produce more significant data.
Again the blank turned out to have very good inherent resistance to corrosion. The additives did not help that much. See Table I.
Three percent M-380 and 1% M-119 improved the humidity resistance much more than any other additive package after 1000 hours of exposure. The Butrol 23 coating was much worse in humidity resistance, although the salt spray resistance was better than the other samples. The 3% M-380/1% M-119 additive coating had poor salt spray resistance. Previous
work has shown that in a clear coating formulations, 3% M-380/1%M-119 improve the salt spray and humidity resistance significantly. By modifying this pigmented formulation slightly, the salt spray resistance should improve substantially. See Table I, Figure 2, and Formulations 3 and 4 (Attachment).
A combination of M-380, M-118ex [M-119 and EXP 391] proved to have equal good corrosion protection compared to Butrol 23. See Table I Figure 3, and Formulations 5 and 6 (Attachment). The humidity resistance; however, was better with no corrosion inhibitors.
Conclusions: Several Cortec additives are equal or superior to Butrol 23 in a number of coatings.
Future Work:There are several additional organic corrosion inhibitors that will be evaluated in the future to a greater extent: M-238 (emulsified), Sicorin, and combinations of these additives with inorganic pigments. One customer is now using M-238 as an additive in a coating.
Project No. 01-040-1325(bis)
Estimated Cost of Project: $12,500.00
To: Barry Fisher
Van Horn Metz
For: Several potential additive customers
From: Mike Prenosil and Luc Butzon
Date: September 6, 2001