What are the selection criteria for gold silicone pigments?
1. Basic performance adaptability
1. Compatibility with silicone matrix
Core requirement: Masterbatch must be able to stably mix with silicone (especially the basic silicone of the model used) without rejection, stratification or chemical reaction.
2. Temperature resistance matching
Core requirement: Masterbatch must withstand the temperature of silicone processing and use (including mixing temperature, vulcanization temperature, and the possible long-term use temperature of the product, such as high-temperature resistant silicone products must withstand more than 150°C).
2. Color stability and consistency
1. Color concentration and hiding power
Color concentration: It needs to match the target color (such as light gold, sub-gold, bright gold). Too high concentration may lead to uneven mixing, and too low concentration requires a large amount of addition, which increases costs and may affect the performance of silicone. By adjusting the addition ratio (such as 1%-5%) for testing, determine the concentration range that can stably present the target color.
Hiding power: If the silicone itself has a base color (such as translucent silicone), the masterbatch must have sufficient hiding power to avoid the base color from showing through and causing the color to turn gray; if the transparent silicone needs to have a "translucent gold" effect, the hiding power must be controlled to avoid complete opaque (opaque).
2. Color difference and batch stability
Color difference control: The color of the masterbatch itself must be consistent with the standard color card (can be detected by a spectrophotometer, the smaller the ΔE value, the better, generally requiring ΔE≤1), to avoid color casts visible to the naked eye (such as reddish, yellowish, dark).
Batch stability: The color difference between different batches of masterbatches must be extremely small (same ΔE standard), otherwise it will lead to inconsistent colors of different batches of products. Suppliers can be asked to provide batch test reports, or randomly sample different batches for comparison.
III. Dispersibility (directly affects color uniformity)
Core requirements: The masterbatch must be evenly dispersed in the silicone, without granularity, and without forming local color blocks or stripes.
Judgment method:
Observe the cross section of the rubber compound after mixing: there are no obvious undispersed masterbatch particles (can be observed under a microscope, the particle diameter must be ≤5μm, invisible to the naked eye);
After molding, the product (especially the thin-walled part) has no "color spots" or "color lines" on the surface, and the color is consistent overall.
Related factors: The particle size distribution of the masterbatch (it is recommended that the particle size is uniform and matches the silica gel particles) and the carrier resin (if it contains a carrier, it must be compatible with silica gel) will affect the dispersibility, and the masterbatch that has been "pre-dispersed" is preferred.
