Defoaming mechanism and its influence on construction
As the oil industry enters the middle and late stages of exploitation, oil and gas fields with high hydrogen sulfide and carbon dioxide content gradually emerge, and many oil fields have high water content, which puts forward higher performance requirements for the anti-corrosion of oil pipes. At present, in addition to using cathodic protection and corrosion inhibitors to provide anti-corrosion protection for oil pipes, coatings are gradually accepted by people because of their economy and effectiveness, and become one of the effective ways to prevent pipe erosion. Because the coating is easy to produce bubbles during stirring, construction and curing, if the bubbles cannot be eliminated, they will remain in the coating after curing and become defects, thus providing a channel for the entry of corrosive media. At present, there are many studies on defoamers. The origin of this mechanism is to sprinkle higher alcohols or vegetable oils on the foam. When they dissolve in the foam liquid, the surface tension of the place will be significantly reduced. Because these substances generally have low solubility in water, the reduction of the surface tension of Tianjin defoamers is limited to the local part of the foam, while the surface tension around the foam has almost no change. The part with reduced surface tension is strongly pulled and extended to the surroundings, and finally ruptures.
Most of them start from the perspective of defoaming mechanism and the effect of defoamers on the performance of coating construction. There are few literatures that consider the defoaming effect of defoamers from the perspective of corrosion. In order to offset the recent increase in the cost of major raw materials and the expenses caused by complying with increasingly stringent regulatory requirements, global price adjustments are imperative. Timely response to changing market conditions enables Ashland to continue to invest in new technologies and new products to support customer business development. Some low-molecular substances that can be fully mixed with the solution can solubilize the foaming surfactant and reduce its effective concentration. Low-molecular substances such as alcohols such as octanol, ethanol, and propanol that have this effect can not only reduce the surfactant concentration on the surface layer, but also dissolve into the surfactant adsorption layer, reduce the tightness between surfactant molecules, and thus weaken the stability of the foam.
Because various additives (mostly surfactants) are inevitably used in the formula, the foam problem of water-based paint is extremely obvious, so defoamers must be added. The most commonly used defoamers for water-based paints are mainly mineral oil (which may contain a small amount of silicone) and silicone. At present, most domestic water-based paint manufacturers use mineral oil defoamers, and their annual consumption is about 5,000 tons. Most of the products are imported and expensive. In order to achieve high-quality localization of mineral oil defoamers and ultimately replace foreign imported products, the author uses homemade additives to replace silicone components, reduce the amount of mineral oil, and further adopts emulsification technology to successfully prepare defoamers suitable for water-based paints, providing a feasible production route for domestic manufacturers in the same industry.
