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 Cortec’s 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-380

Cortec M-118exp. (71% EXP-391+29% M-119)

Butrol 23 (Calcium modified barium metaborate)

Zinc Phosphate

Rohm and Haas, PR71, latex

Eastman, Aquamac 715, latex

NeoCryl XA-6109, latex

NeoCryl A-639, latex

Setalux 373372, Akzo, latex

Draw down bar

Thickness gauge

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 Cortec’s additives. The additives tested in each latex were as follows:

    1. None = no corrosion inhibitor
    2. 8.1% Butrol 23
    3. 3% M-380 + 1% M-119
  1. 1.5% EXP-391+1.2% M-119(modified)
  2. 2% M-119(modified)+0.7% Zinc Phosphate+0.3% Sicorin
  3. 1.9% EXP-391 + 0.8% M-119(modified)
  4. 3.3% Butrol 23 + 2.3% M-119(modified)

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 Cortec’s 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:

    1. The Butrol 23 can be dispersed in the M-119 (modified). An improved grind and a higher gloss result.
    2. The total cost of this blend is less
    3. This blend can be post added
    4. The stability of the coating appears to be better.

See Figure 1 and Formulations 1 and 2 (Attachment).

Aquamac 715

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.

NeoCryl XA-6109

Again the blank turned out to have very good inherent resistance to corrosion. The additives did not help that much. See Table I.

NeoCryl A-639

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).

Setalux 373372

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.

    1. With some latex coatings, corrosion inhibitors do not improve the corrosion protection.
    2. M-119 (modified) is not only a good corrosion inhibitor, but it can be used to disperse difficult to grind pigments such as Butrol 23. Gloss and corrosion inhibition improve synergistically.
    3. M-118exp. is a good inhibitor and will be introduced as a new product. A separate report will be issued on this product.

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


Boris Miksic

Ashish Gandhi

Anna Vignetti

Vanessa Schultz

Christophe Chandler

Art Ahlbrecht