Why Does xử lý UV Turn Yellow? Professional Analysis and Solutions

🔍 Problem Overview

Material yellowing during xử lý UV is a common technical problem, especially in applications requiring high transparency. Yellowing not only affects product appearance but may also impact material performance and Dịch vụ life.

Main manifestations: Material color turns yellow after curing, transparency decreases, glossiness reduces

1. Photoinitiator Decomposition Producing Free Radical Residues

Mechanism: During xử lý UV, photoinitiators rapidly decompose under UV irradiation to produce free radicals. If free radicals cannot fully participate in the reaction and remain as residues, they cause material yellowing.

• Improper photoinitiator selection
• Excessive photoinitiator concentration
• Photoinitiator aging or poor quality

2. Oxidation Reactions Causing Material Discoloration

Mechanism: Resins and additives in UV materials undergo oxidation reactions when exposed to light and oxygen, producing peroxide structures and free radicals that cause transparent material discoloration.

• Oxygen damage to unsaturated double bonds
• Nhiệt độ cao accelerates oxidation reactions
• Long-term exposure to strong light or Nhiệt độ cao

3. UV Stabilizer Degradation

Mechanism: UV stabilizers added to protect UV materials degrade and lose their protective effect under prolonged UV exposure.

• Improper stabilizer selection
• Insufficient stabilizer concentration
• Excessive UV exposure time

4. Improper Curing Parameter Settings

Mechanism: Excessive light Cường độ or overexposure during curing increases the risk of yellowing.

• đèn UV power too high
• Exposure time too long
• Irradiation distance too close
• Lack of precise energy control