Liquid silicone rubber (LSR) is a remarkably versatile material that offers exceptional performance across countless applications. While LSR naturally appears clear to opaque white, it can be transformed into almost any color. At Apple Rubber, we’ve mastered the process of creating vibrant, consistent, colorful compounds that maintain LSR’s superior physical properties.
The Fundamentals of LSR Coloration
Creating colored silicone compounds is a precise science. The standard formulation uses a 98% LSR base material with 2% colorant by weight, though this ratio can range from 1-3% depending on the desired color intensity.
While clear standard LSR offers excellent optical properties, it may experience yellowing over time—an important consideration for long-term applications where appearance matters.
One significant advantage of LSR is that color remains consistent across different hardness grades, allowing for color matching even when mechanical properties vary.
It’s worth noting that a part’s thickness significantly influences the part’s color. Thinner sections will naturally appear lighter than thicker ones, even when made from an identical compound.
The Purpose Behind the Palette
Color serves multiple functions beyond the aesthetic:
Distinguishing between similar components
Indicating revision levels in different product iterations
Providing visual verification during assembly processes
Our Manufacturing Approach
Apple Rubber’s coloration process integrates seamlessly with part production. As the LSR flows toward the molding press, a concentrated color paste is introduced as a third stream, ensuring uniform tinting throughout the material before the molding and curing processes begin.
Precision Color Matching
Using the CAPSURE® color meter, we match colors precisely to the Pantone system from a database of over 10,000 standardized colors. Each color is tested on 6″ × 6″ × 0.080″ specimens using Silopren™ LSR 2070 with our standard 2% color paste concentration.
With more than 70 color options available and the capability to create custom matches, Apple Rubber has both the expertise and technology to meet your exact specifications. Whether your application demands medical-grade colorants, standard shades, or precise color matching, our team will help determine the optimal solution.
Get in touch with our engineering team here.