Volume 3 Issue 5
What’s Happening at Missouri S&T:
Fall Short Course Are Coming Up Soon!!!
**These courses are filling up fast! There are still a few open spots, so register today for Fall courses!!**
This fall we will be offering “Basic Composition of Coatings¿? September 11-15, 2006 and “Introduction to Paint Formulation¿? October 9-13, 2006 . The Basic Composition course is intended for new personnel in the coatings profession. It targets the components of coatings (resin, pigments, extenders, solvents and additives), testing and specifications, general formulation and manufacturing methods. Basic Composition is primarily a lecture course with several laboratory demonstrations. The Introduction to Formulation course is intended to give the person a fundamental knowledge of how to approach a starting formulation and troubleshoot it. This course involves both lecture and laboratory work For more information see our web site at http://coatings.mst.edu and to register contact Michael Van De Mark at email@example.com or call 573-341-4419. **Both courses held on the Rolla campus**
Spring 2007 Short Course Dates
Summer 2007 Short Course Dates
Next summer we will be offering "Introduction to Coatings Composition and Specifications" July 16-18, 2007 , in St. Louis Missouri.
See you at ICE 2006!
We hope to see you at the ICE show in New Orleans, LA on November 1-3, 2006. Stop by our booth and enter to win a St. Pat’s Sweat Shirt. Five shirts will be given away at this year’s show. We will have resumes of students and the display will feature our new equipment and research efforts. Come by and discuss what we are doing and how we can interact better with your company.
Michael Roy Beckmann Receives Honorary Degree
The University of Missouri-Rolla awarded 11 honorary professional degrees during its spring commencement in May 2006.
Mike Beckmann earned a bachelor’s degree in chemistry from Missouri S&T in 1982. Beckmann’s wife, Karen, earned a bachelor’s degree in chemistry from Missouri S&T in 1981 and a master’s degree in chemistry from Missouri S&T in 1983. Beckmann’s first position was with Westin Engineering. Both Beckmanns then joined Riechhold Chemical in Pensacola, Fla. Later, they were both hired by PPG Industries, where Karen has risen to become an award-winning development chemist. Mike benefited from a range of experiences at PPG in various technologies and departments, including serving as a technical liaison to manufacturing processes. In 1992, Beckman purchased Bonstone Materials, a producer of high performance epoxy adhesives. While at Missouri S&T, Mike was a member of Tau Kappa Epsilon. The Beckmanns live in Muskego, Wisconsin.
Technical Insights on Coatings Science
The Coating System
By Michael Van De Mark, Director, Missouri S&T Coatings Institute
One of the most frequent calls to the Missouri S&T Coatings Institute is in regard to coatings failure or problems with meeting performance specifications. When a coating fails, most end users tend to blame the paint while the paint manufacturers tend to blame the end users. Also, regulations such as VOC, stack emissions, toxicity, or heavy metal content may drive changes which the end user and the coatings supplier must meet. To address any and all of these problems, the “Coating System¿? must be fully considered.
I define the coatings system as the substrate (metals, plastics, etc. to be painted), cutting and lubrication oils, handling methods such as gloves, rubber grips etc., cleaning methods and solutions, pre-treatments, primers, base coats, top coats, curing methods, and, if needed, packaging and future re-coating materials and methods. All these components comprise the “Coating System¿?. Too often the “Coating System¿? is restricted to the paint booth, curing method and maybe the cleaning step. However, the substrate has been contaminated by oils, welding debris, stamping oils and many other things during manufacturing. These contaminants must be removed or they must be compatible with the coating. For example, welding debris and oxidized metal will not allow a zinc-rich primer contact with the bare steel. Another example is residual mineral oil cutting fluids on metal will not allow a water borne coating to adhere to the metal and can cause defects such as craters or non-wetting. Personal care products such as deodorants, makeup, hand lotion, or hair care products can end up on the substrate. Many of these products contain oils or silicone which can reduce adhesion or cause craters. Care must be taken to avoid these being used or brought into the plant.
Today many end users are switching to water borne coatings, switching technologies to lower VOC, eliminating chrome, or eliminating a washing or pre-treatment step. When these changes are to be implemented, the “Coating System¿? must be evaluated. If, for example, water borne coatings are to be used instead of a solvent borne coating to paint the metal, what should be evaluated? Here, the “System¿? would include all the factors. Special emphasis should be given to the contaminating oils. Hydrophobic oils such as mineral and vegetable oils will tend to cause defects or will not be compatible with the coating. The cleaning chemicals, the surfactants, must emulsify all the oils and remove them from the substrate. If the cutting oils are water compatible such as a polyethylene oxide, the coating will be able to better tolerate trace residuals on the surface. Thus, when switching from a solvent borne coating to a water borne coating it may be necessary to change the cutting fluid or the surfactant in the degreasing unit.
When developing a coating for a client, it is necessary to understand the full coating system. Either communication must be free and detailed or a visit to the site to examine the full system in person may be necessary. The term proprietary can get in the way of getting the best system for a company. If part of the process is proprietary, the coating may not be optimized for the system. However, if the full disclosure of the process and methods are made, the formulator can design and work with the company to maximize the coating’s performance as well as the over-all process. A simple change in the process may improve the over-all system. An excellent example was poor adhesion of an OEM coating which needed to be 6 mils thick on a very large part. Modifying the process to use 3 coats with a flash off time of 20 minutes between coats improved the adhesion by an order of magnitude. Since the parts were so large, painting was continuous and the thinner coating per pass reduced the amount of sag.
Another area of the system which can be problematic is the curing ovens. Generally curing ovens cause chemical reactions which cross-link the coating making it harder and more durable. However, if the primer is too highly cross-linked, the top coat may not have good adhesion to it. The top coat should penetrate into the surface of the primer and entangle. We have found that if the oven time or temperature is reduced slightly, the cross-link density drops and adhesion of the top coat to the primer significantly increases. This change in process reduces cost and improves the coating. It should be noted that dropping the temperature too low will reduce the cross-linking to the point that corrosion resistance, tensile strength or other properties will be adversely affected. Optimization of the oven for a given “coating system¿? is necessary and not just optimized for that single coating layer.
Other general sources of problems within the system can include: water purity, compressed air purity, heating/cooling air contamination, visitors, air filters, humidifiers, open windows or doors, grinding or welding dust, dirty gloves, exhaust fan speed (air flow), as well as humidity and/or temperature variation. Problems with the system are often hidden and may require an independent observer to view the system for potential problems. We are often too close to a problem to see it. Internal observations coupled with an external person’s corroboration can help justify the expenditure of effort or money to solve a problem.
Engineer education is critical. Engineers do not take a course in coatings in college and yet are required in their job to specify all the parameters, develop and maintain the “Coating System¿? and determine the best coatings to use. It is no wonder that communications between the engineer and the paint manufacturer is often strained. Often, for larger customers, the paint manufacturer has a coatings person assigned to the client to help trouble shoot until the system is running trouble free. Any change over in technology produces a steep learning curve which must be overcome to reduce problems.
In conclusion, proper selection or modification of processing oils, cleaning products, and surface treatments can improve the “Coating System¿? so that the end product is vastly superior. Know what the “SYSTEM¿? is and make sure that the entire system is addressed. Overlooking a key component of the system can result in a large number of problems.
Is there a topic you would like discussed? Contact us by e-mail at firstname.lastname@example.org.
|September 11-15, 2006 Basic Composition of Coatings This course provides an overview of the components of paint and how they work. Participants are also introduced to methods for testing and manufacture of paint.|
|October 9-13, 2006 Introduction to Paint Formulation This course provides techniques used in|
formulating paint from raw materials. It involves formulating and making paint in the laboratory, "Hands on!"
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