Improve protection performance: Tips and suggestions for using PU varnish oil repellent

1. Preparation before use

Product compatibility test

Substrate test: Before formal use, a small area coating test is required on the target substrate (such as plastic, metal, paper, leather, etc.) to verify the compatibility of the oil repellent with the PU varnish to avoid problems such as delamination, cracking or insufficient adhesion.

Environmental simulation: Simulate the actual use environment (such as temperature, humidity, and light conditions) to test the anti-oil performance and durability of the coating.

Equipment and tool preparation

Spraying equipment: Select a suitable spray gun (such as air spray gun, high-pressure airless spray gun, etc.) according to the type of substrate to ensure uniform spraying.

Stirring tool: Use an electric stirrer to fully mix the PU varnish and the oil repellent to avoid performance differences due to uneven stirring.

Protective equipment: Operators need to wear protective masks, gloves and goggles to avoid direct contact with chemicals.

Environmental control

Temperature and humidity: The construction environment temperature is recommended to be controlled at 15-30℃ and the humidity ≤70% to ensure the drying speed and adhesion of the coating.

Ventilation conditions: Ensure that the working area is well ventilated to avoid the accumulation of volatile organic compounds (VOCs).

2. Key operations during use

Proportion and mixing

Add strictly according to the proportion: According to the product manual, add the anti-oil agent to the PU varnish according to the recommended proportion (such as 5%-10% anti-oil agent addition) to avoid excessive or insufficient addition.

Full stirring: After mixing, continue stirring for 10-15 minutes to ensure that the anti-oil agent is evenly dispersed in the PU varnish.

Coating process

Spraying thickness: Control the coating thickness between 20-50μm. Too thick may cause sagging or poor drying, and too thin will affect the oil resistance.

Drying conditions:

Natural drying: It needs to be left at room temperature for more than 24 hours. The specific time depends on the ambient humidity and coating thickness.

Forced drying: If an oven is used, it is recommended to control the temperature at 60-80℃ and the drying time for 30-60 minutes to avoid high temperature causing yellowing of the coating or performance degradation.

Multi-layer coating: For high-demand surfaces (such as mobile phone shells), it is recommended to use the "primer + topcoat" process, and each layer of coating must be fully dried.

Precautions

Avoid cross-contamination: Use special tools and containers to avoid mixing with other chemicals.

Real-time monitoring: Check the appearance of the coating regularly during the coating process, and immediately deal with problems such as sagging and pinholes.

3. Maintenance and testing after use

Performance testing

Anti-oil stain test:

Water drop angle test: The water drop angle on the coating surface should be ≥100°, indicating good oleophobicity.

Oil stain wipe test: Apply edible oil or mineral oil to the surface, wipe with a dust-free cloth after 30 seconds, and there should be no residual oil stains.

Adhesion test: Use the cross-cut method or tape stripping method to ensure that the coating adhesion reaches level 0 (no shedding).

Weather resistance test: Use ultraviolet accelerated aging tests (such as QUV tests) to verify the performance stability of the coating under long-term light.

Storage and re-inspection

Sealed storage: Unused mixed liquid must be sealed and stored to avoid contact with air and deterioration.

Regular re-inspection: Perform a performance re-inspection on inventory products every 3 months to ensure stable quality.

Problem handling

Common problems and solutions:

Whitening of the coating: It may be caused by excessive humidity or insufficient drying, and the drying conditions need to be optimized.

Poor adhesion: Check whether the surface treatment of the substrate is in place (such as polishing, degreasing), or adjust the proportion of oil-repellent agent added.

Insufficient gloss: Appropriately increase the amount of PU varnish or adjust the spraying pressure.

4. Safety and environmental protection recommendations

Safe operation

Waste disposal: Waste mixed liquid and cleaning solvents must be disposed of in accordance with hazardous waste disposal regulations to avoid environmental pollution.

Emergency measures: If the skin or eyes come into contact with the oil-repellent, rinse immediately with plenty of clean water and seek medical help.

Environmental compliance

VOCs control: Choose PU varnish oil-repellent with low VOCs content to reduce pollution to the atmospheric environment.

Regulatory compliance: Ensure that products comply with local environmental regulations (such as EU REACH, China GB standards).