How to control the color difference of hot melt adhesive particles when changing batches? Comparison and actual measurement of color difference between two suppliers

Where does batch color difference come from?

hot melt adhesive pelletsThe color depends on the natural color of the EVA resin batch, the type of tackifying resin, the whiteness of the filler, and the amount of coloring agent added. Small fluctuations in each batch of raw materials can lead to color differences in the finished product, especially white and transparent adhesive particles, which are most sensitive to color differences. The color difference that can be distinguished by the naked eye only requires Δ E>1.5.

Comparison of color difference between batches of A factory and B factory

Color difference control method

• Require suppliers to provide color difference testing reports (Δ E value) for each batch, and reject if it exceeds 1.0
• The tolerance for color difference of dark colored rubber particles (yellow/brown) is higher than that of white/transparent, and Δ E ≤ 2.0 is acceptable
• Try to use the same batch of adhesive particles for the same project to avoid changing batches midway
• When it is necessary to change batches, a small sample comparison must be made first to confirm that the color difference is within an acceptable range before mass production can be launched

Sunlife hot melt adhesive comes with color difference detection data for each batch upon leaving the factory, with Δ E controlled within 0.8. Guangzhou Sunlife Trading supports customer sample comparison to ensure color consistency between batches.

Frequently Asked Questions

• Q: Does color difference affect bonding performance?
  A: Minor color differences do not affect, but significant color differences may indicate formula deviation and require simultaneous testing of adhesive performance.
• Q: Is it harder to control the color difference of transparent adhesive particles than white?
  A: Yes, it is. Transparent adhesive particles have no covering power, and the fluctuation of the substrate’s natural color is directly manifested; The white adhesive particles are covered with titanium dioxide, making color difference easier to control.