SILIKE Releases Comprehensive Guide for Anti-Scratch Additives in PP/TPO Compounds

SILIKE, a company specializing in anti-scratch solutions for automotive interiors, has released a comprehensive technical selection guide for PP/TPO compounders, Tier-1 suppliers, and automotive material teams. The guide aims to help these professionals choose the right anti-scratch additives for various automotive interior parts, ensuring that surfaces remain scratch-resistant and visually appealing over time.

The guide highlights the challenges faced by talc-filled PP/TPO compounds, where scratches can become more visible due to the lighter filler-containing regions becoming more prominent on dark-colored components. Scratch resistance is crucial for parts such as door panels, dashboards, center consoles, and pillar trims, which are repeatedly exposed to mechanical damage and environmental factors.

One of the key factors in selecting an effective anti-scratch additive is the initial ΔL value, which measures the change in lightness between the scratched and original surface. However, the guide emphasizes that ΔL should not be the sole criterion for evaluation. The additive must maintain the required scratch resistance and surface appearance over time without introducing unwanted changes in surface stability, gloss, odor, or VOC performance.

Silicone-based technologies are widely used to improve surface performance by reducing friction between the molded polymer surface and the object moving across it. High- and ultra-high-molecular-weight silicone masterbatches provide a convenient pelletized form for handling and dosing. However, the effectiveness of these additives depends on their compatibility with the polymer matrix and the specific formulation.

The guide outlines six critical factors to consider when selecting an anti-scratch additive:

1. Polymer Matrix: The actual resin system, whether PP homopolymer, PP copolymer, or PP/EPDM-based TPO, may require different additive approaches based on compatibility. 2. Talc and Filler Loading: Talc loading significantly influences scratch visibility and additive response. The anti-scratch additive should be evaluated in the actual filled formulation rather than only in neat resin. 3. Target Scratch Test and ΔL: The selection process should start with the test requirement, such as PV3952, GMW14688, or customer-specific scratch methods. The final result can depend on various factors, including applied load, stylus geometry, surface grain, conditioning, part color, and measurement method. 4. Aging and Long-Term Surface Stability: A good initial scratch result does not automatically mean suitability for long-term automotive use. Heat aging, UV exposure, and temperature cycling may reveal changes that are not visible immediately after molding. 5. VOC, Odor, and Fogging: Automotive cabin materials are evaluated as complete formulations. The anti-scratch additive should support the formulation target rather than be treated as an independent guarantee of final compliance. 6. Gloss, Grain, and Tactile Quality: Scratch resistance should not be improved at the expense of the intended surface design. The selected additive should be evaluated for its effect on gloss, grain definition, surface uniformity, color consistency, and hand feel.

SILIKE offers a series of PP-based silicone anti-scratch masterbatches for automotive PP, TPO, and related thermoplastic systems. The portfolio includes Anti-scratch Masterbatch LYSI-306, Long-Term Scratch Resistance Additive LYSI-306C, High Scratch Resistance Silicone Masterbatch LYSI-306H, Non-Migrating, Non-Sticky, High-Temperature Stable Additive LYSI-306G, and Ultra-Low VOC, Non-Tacky Anti-Scratch Additive LYSI-906. These grades are positioned around polymer compatibility, long-term scratch performance, surface stability, and low-VOC requirements.

In an internal evaluation, the long-term scratch resistance agent LYSI-306C demonstrated low visible scratch contrast under defined test conditions. The material system used was a selected PP/TPO formulation, with a LYSI-306C dosage of 1.5 wt%. The scratch load was set at 10 N, and the ΔL was less than 1.5, meeting the PV3952 target and the GMW14688 target.

For high-talc PP/TPO compounds, the focus is on scratch whitening and filler compatibility. For black or dark-colored door panels, the priority is low visible scratch contrast. Matte dashboards require scratch resistance with gloss retention, while fine-grain molded surfaces need surface uniformity. High-touch center consoles should have mar resistance and tactile quality, and high-temperature interior parts require long-term surface stability. Low-VOC compounds need to meet VOC, odor, and fogging requirements, and PP-Homo-rich compounds should focus on PP-Homo compatibility.

The guide provides a useful first screening before formulation trials begin, ensuring that the selected additive meets the specific requirements of the application.