How to correctly select an acrylate leveling agent suitable for a specific coating system?
How to correctly select an acrylate leveling agent suitable for a specific coating system?
1. Selection based on coating type
Solvent-based coatings: The solvent system of solvent-based coatings has requirements for the solubility of acrylate leveling agents. It is necessary to select a leveling agent with good solubility and that can match the solvent system. For example, for aromatic solvent-based coatings, select an acrylate leveling agent containing aromatic solvent-soluble groups, such as some acrylate copolymer leveling agents containing benzene ring structures, which can effectively migrate to the surface in the system, reduce surface tension, and achieve good leveling.
Water-based coatings: Water-based coatings use water as a solvent, and require acrylate leveling agents to have good hydrophilicity and water dispersibility. Usually, acrylate leveling agents containing hydrophilic groups such as carboxyl and hydroxyl groups are selected. These groups can form hydrogen bonds with water to make them evenly dispersed in the water-based system, such as water-based acrylic emulsion coatings. Carboxyl-containing acrylate copolymer leveling agents can improve the surface tension difference between water and film-forming substances and improve the leveling effect.
Powder coating: The processing and curing process of powder coating is special, and it is necessary to select an acrylic leveling agent that can spread quickly and promote leveling in a high-temperature molten state. Generally, an acrylic leveling agent with a high molecular weight and a suitable glass transition temperature is selected. When the powder coating is heated and melted, it can reduce the viscosity of the system, promote molecular flow, and form a smooth coating after cooling and curing.
2. Select according to the performance requirements of the coating
High gloss requirements: If you pursue a high-gloss coating, such as automotive topcoat and high-end furniture paint, select an acrylic leveling agent that can significantly reduce surface tension and promote uniform molecular arrangement. This type of leveling agent can make the coating surface smooth like a mirror and reflect light efficiently. For example, the extremely low surface energy of fluorinated acrylic leveling agents can greatly improve the gloss of the coating.
Good anti-shrinkage performance: For coating systems that are prone to shrinkage problems, such as coatings containing more low-surface tension substances or applied in high-humidity environments, select acrylic leveling agents that can quickly reduce surface tension and have a certain wetting ability. It can quickly eliminate shrinkage caused by surface tension differences. For example, some acrylic leveling agents with special surface active groups can quickly spread and wet the substrate to prevent shrinkage.
Excellent balance between leveling and anti-sagging: In some coating applications that require thick coating, such as building exterior wall coatings, it is necessary to ensure good leveling and prevent sagging. At this time, select an acrylic leveling agent with appropriate rheological properties adjustment ability, reduce viscosity under construction shear force to achieve leveling, and quickly increase viscosity after the shear force disappears to prevent sagging, such as acrylic copolymer leveling agents containing special rheological modification groups.
3. Combined with the construction process selection
Spraying construction: Spraying requires the coating to have good atomization and leveling properties. Select an acrylic leveling agent that can reduce surface tension, improve atomization effect and does not affect the drying speed. For example, in electrostatic spraying, the leveling agent cannot affect the conductivity of the coating. It is necessary to select an acrylic leveling agent with little effect on electrical properties to ensure a smooth spraying process and coating quality.
Brush and roller coating: Brush and roller coating are prone to produce brush marks and roller marks. It is necessary to select an acrylic leveling agent that can quickly level and eliminate construction marks. Generally, products with moderate molecular weight and good fluidity are selected to make the coating evenly distributed in a short time after construction to reduce marks.
Dip coating: Dip coating requires the coating to spread quickly on the surface of the workpiece without sagging. Select an acrylic leveling agent that can quickly reduce surface tension and increase the stability of wet film thickness to ensure that the coating on the surface of the workpiece is uniform after dipping.
4. Consider cost and cost performance
Cost limitation: Consider cost factors under the premise of meeting the performance of the coating. The prices of acrylic leveling agents of different types and brands are different. By comparing the performance and prices of different products, choose the most cost-effective one. For example, for ordinary industrial coatings produced on a large scale, when ensuring basic leveling performance, conventional acrylic leveling agents with lower prices but stable performance can be selected.
Comprehensive cost performance evaluation: In addition to direct costs, it is also necessary to consider the impact of leveling agents on the overall performance of the coating and subsequent production efficiency. For example, although some high-performance acrylic leveling agents are expensive, they can reduce the defective rate and improve production efficiency. In the long run, they have a higher overall cost-effectiveness and are suitable for high-end coating products with high quality requirements.