Guide to the use of alcohol-soluble leveling agents: scientific operation from addition to film formation

Guide to the use of alcohol-soluble leveling agents: scientific operation from addition to film formation

In the construction of coatings, the leveling agent is like a "surface engineer", which controls the flow and spreading behavior of the coating to achieve a smooth and flawless coating effect. Alcohol-soluble leveling agents have become the preferred additives that take into account both environmental protection and performance due to their natural compatibility with alcohol solvents. The following is an analysis of its use from an operational perspective.

1. Accurate measurement: find the balance point

The amount of leveling agent added is a key parameter affecting the quality of the coating. The usually recommended amount is 0.3%~0.8% of the total paint amount, but the specific amount needs to be determined by the "gradient test method": in the same formula, the amount of leveling agent is adjusted in a gradient of 0.1%, and the changes in shrinkage, sagging and glossiness of the coating are observed. For example, in wood coatings, an addition of 0.5% may achieve a balance between leveling and anti-sagging, while automotive repair paints may require 0.7% to cope with complex curved surfaces. Excessive use will lead to too low surface tension of the coating film, causing shrinkage; insufficient use will not eliminate brush marks.

2. Mixing process: step-by-step fusion

Pre-dilution treatment: Mix the leveling agent with co-solvents such as ethylene glycol and propylene glycol in a ratio of 1:2~1:4 to reduce its viscosity and facilitate uniform dispersion. For example, a certain acrylic leveling agent needs to be diluted with isopropyl alcohol to a transparent state before adding it to the coating system.

Add in stages:

Basic stage: Put the polyol resin and part of the solvent into the paint mixing tank and stir at a low speed until uniform.

Pigment dispersion stage: Before grinding the pigment, add the diluted leveling agent to use its wettability to improve the pigment dispersion efficiency.

Final adjustment stage: After the paint is mixed, add the remaining leveling agent to avoid early excessive migration and affect the stability of the system.

3. Construction environment: control variables

Temperature and humidity management: The construction temperature should be controlled at 15~30℃, and the humidity should be lower than 85%. Low temperature will cause the migration rate of the leveling agent to decrease, causing orange peel; high temperature may accelerate the volatilization of the solvent, making it too late for the leveling agent to work.

Wind speed control: During the spraying operation, the wind speed should be lower than 0.5m/s to avoid excessive drying of the paint during the flight process, resulting in dry spray defects.

4. Construction skills: Adapting the coating method

Spraying: Adjust the spray gun pressure to 0.3~0.5MPa, and keep the spraying distance at 20~30cm to ensure uniform atomization of the paint. Leveling agent can reduce surface tension and make the paint mist easier to spread.

Brushing/roller coating: Use the "thin coating multiple times" process, and control the thickness of each coating to 30~50μm. The leveling agent migrates between coatings to eliminate interface marks.

5. Compatibility verification: Avoid formula conflicts

In the development of new coatings, the matching of the leveling agent with the resin and pigment needs to be verified through a "compatibility test": add the leveling agent to the coating according to the recommended amount, and observe whether stratification and turbidity occur after standing for 24 hours. If phase separation occurs, adjust the type of leveling agent or reduce the amount. For example, non-ionic leveling agents should be selected in polyurethane coatings to avoid reaction with isocyanates.

6. Storage and reuse: Extending service life

Unopened alcohol-soluble leveling agents should be stored in a cool and dry place, away from direct sunlight, and the shelf life is usually 12 months. If not used up after opening, it needs to be sealed and a desiccant added to prevent moisture absorption and agglomeration. Stir until uniform before reuse. If slightly turbid, it can be heated to 40°C to restore transparency.

From the laboratory to the construction site, the use of alcohol-soluble leveling agents must take into account scientific measurement and process details. Through precise addition, step-by-step mixing, environmental control and compatibility verification, its leveling performance can be maximized, and finally a mirror-like coating effect can be presented. This process is both a practice of material science and an interpretation of construction art.