What is the difference in aging resistance between LOCA and OCA?
Date:2026-06-05
What is the difference in aging resistance between LOCA and OCA?
From the perspective of aging resistance, high-quality water-based adhesives and sheet adhesives can meet the lifespan requirements of the vast majority of consumer electronics products. However, sheet adhesives (OCA) usually perform better in terms of resistance to yellowing and long-term stability, and their technology is also more mature.
Their differences in aging resistance are mainly reflected in the following aspects:
1. Anti yellowing performance: The sheet adhesive is more stable
This is the main difference in aging performance between the two.
Water glue (LOCA): Some early or poorly formulated water glue poses a risk of yellowing during long-term use, especially when exposed to ultraviolet radiation and high temperature environments. This is because its liquid chemical composition has slightly weaker stability under complex aging conditions. However, many high-end water-based adhesives now claim to have excellent anti yellowing performance, depending on the product specifications.
OCA: As a solid adhesive film, its formula has high stability and excellent UV aging resistance. In accelerated aging testing, the yellowing index (b-value) of well-known brand products is strictly controlled at an extremely low level (such as only increasing from 0.47 to 0.72), far below the threshold that can be detected by the naked eye. This is also why high-end smartphones and other devices with strict display requirements have always preferred OCA for many years.
2. Moisture and heat resistance and reliability: The advantages of sheet adhesive are obvious
In harsh environments such as high temperature and high humidity (such as double 85 test: 85 ° C/85% RH), the differences are more prominent:
Advantages of adhesive film: Mature OCA products can easily pass the 1000 hour double 85 test without experiencing issues such as bubble rebound, adhesive cracking, or performance degradation. This stability makes OCA the preferred choice in fields such as automotive and aerospace that require high reliability.
Potential risks of water-based adhesives: Poor quality water-based adhesives may experience colloidal softening, decreased adhesion, and even corrosion of polarizing films or backlight modules in long-term humid and hot environments.
3. Different aging failure modes
Water gel: The main risks are yellowing, corrosion, and delamination. Its failure is more related to the chemical stability of the material itself.
Adhesive: The main risk is bubble rebound. This is usually due to the small residual stress during bonding, which is released under long-term high temperature. But this is a process issue, not a defect in the aging resistance of the material itself. In addition, some high-end OCAs also have UV shielding function, which can protect other components of the screen.
summary
in general:
Pursuing ultimate stability and long-term performance: Especially in scenarios such as automotive and aerospace that require high reliability, or in high-end consumer electronics that have zero tolerance for screen yellowing, OCA is a more reliable choice.
Balancing performance and cost: In scenarios where OCA is unable to handle large sizes, curved screens, etc., choosing high-quality water-based adhesive (LOCA) that has undergone rigorous aging testing verification can also provide very reliable aging resistance and meet daily usage needs.
