Al’s Arrested Alkyd Development
Al Kidd talks to alkyds. Polly Mertz could hear him yelling in the lab across the hall from her lab. “Come on resin, I don’t have all day,” Al was admonishing his 3-liter resin reactor, as if the individual resin intermediate oligomers mixing in the setup could hear his ranting. His frustration was that he had slightly miscalculated the amount of time it would take to reach the final acid number endpoint for his resin synthesis, and he was clearly ready to go home.
Al had gotten his start in the coatings industry synthesizing alkyd resins for Big Time Paint Company. Each alkyd can be tailored to certain properties in a coating by changing the diacids, diols and oils in the resin. And now, since Al had learned about Polly’s project to develop a new alkyd, he was constantly sticking his head in Polly’s office to offer advice about the joys and intricacies of alkyd resins. Polly wasn’t so sure how seriously to take advice from a man that talked to alkyds.
Just a few days before, Lois Bidder, one of the purchasing agents for Big Time Paint Company, had called Polly with a problem. The price of one of the primary drying oils used in making many of the alkyds, linseed oil, derived from flax seed, had spiked. The purchasing department wanted to explore the use of some cheaper and more readily available drying oils in their alkyd resin portfolio. Lois had told Polly, “Of course, the oil change should not affect the properties of the alkyd.” Lois emphasized, “We don’t want the customer to detect any change from the linseed oil alkyd resin we have been using.”
The list of more inexpensive oils that Lois had supplied to Polly included many that she had never heard of. She was surprised that there were so many different oils, and she didn’t know where to start in replacing linseed oil. Thankfully for Polly, Al had literally jumped at the chance to help.
Over the years Al had worked on similar projects because oils used in the manufacture of alkyds were natural products from plants and animals, and their availability was often impacted by weather and crop disasters due to pestilence. Recent oil price fluctuations were due to their growing use in both nutraceutical and food processing, and new technologies like fracking and mining. These natural oils were considered safer and more sustainable raw materials in the manufacture of surfactants and pharmaceuticals.
Big Time Paint Company continued to manufacture alkyds for coatings even though alkyds had reached their maximum usage in the 1970s and had since been replaced by better weathering acrylics and polyurethanes. Now alkyds were making a resurgence due to their versatility in coatings formulations, and because they were bio-renewable and sustainable, since much of the chemical structure of the raw materials is based on natural oils and glycerol. Alkyds had been re-invented as the new GREEN resins by the coating industry.
Al couldn’t help but find it ironic that Polly, with all her synthetic chemical education, was only now learning how to formulate alkyd coatings, one of the oldest coating resin binders. Alkyd resins had been around since the 1930s, even longer than Al had been in the industry. When Al had started in the lab, alkyds, or oil-modified polyesters, were the first polymer a new synthesis chemist learned how to make.
Each day during the last two weeks in the lab, Al would regale Polly with a dissertation about how each oil imparts its own characteristic properties to an alkyd; properties like curing, color, viscosity and performance. But today when Al came into Polly’s office, his voice had gotten quieter and more stoic, as he told Polly his personal story of switching out one oil for another in an alkyd project years before.
“The new resin I developed over 35 years ago by replacing linseed oil with a very similar oil in an alkyd almost got me arrested for indecent exposure!” Al said. Polly suddenly looked up from her computer and sat listening intently as Al told his story.
“I had done a considerable amount of work in the lab and found an oil that gave me the same properties as linseed oil. I had tested the properties of the new alkyd, evaluating dry time, compatibility, viscosity and even color. The new alkyd matched the linseed-based alkyd in all my tests. I scaled up the resin without incident and then ran the first batch in the plant. At the time, I lived with my wife in a small apartment complex not far from the Big Time plant. I stayed late in the night at the plant overseeing the production of the new alkyd. The completion of the plant batch cook wasn’t over until 2:00 AM. About an hour later, when I got back home, I walked into the apartment building and down the stairs to the door of our little apartment. We shared entry with three other apartments, the doors of which were at the three other walls of the square landing. The door was locked and I didn’t have my keys. Sheepishly, I knocked, and when my wife opened the door, rubbing her tired eyes, she demanded, without even looking at me, “Take off your clothes before you take one more step”. I had to take off my clothes, down to my skivvies, in the entranceway to the apartment. I remember thinking I could hear the laughter of the neighbors on the other side of the doors as I piled up my clothes in the hallway…or maybe it was just the meowing of our two cats that we shared our apartment with?”
Why did the replacement of linseed oil with another very similar oil cause Al’s wife to make such a demand? Even though the coating properties of the new alkyd formulation matched perfectly the properties of the old formulation, what had been the unforeseen consequence of changing one oil for another in the formulation?
Read the answer in our January issue!