Guide flags key tradeoffs in PP/TPO anti-scratch additive selection

A new technical guide for automotive compounders and Tier-1 suppliers says PP/TPO interior parts can meet mechanical specs but still fail on visible scratches, gloss and long-term surface stability. It lays out how to evaluate anti-scratch additives for talc-filled and molded-in-color interiors while balancing aging, VOC, odor and surface-quality targets.

Why it matters: - PP/TPO interior parts can pass mechanical testing and still miss automotive appearance targets because of scratch whitening, mar marks, gloss change and surface instability. - The issue is most visible on door panels, dashboards, center consoles, instrument panels and pillar trims that face repeated touch, rub, cleaning and temperature cycling. - For compounders and Tier-1 suppliers, the wrong additive choice can create a part that looks acceptable on day one but fails after aging or in dark-colored, talc-filled formulations.

What happened: - Chengdu Silike Technology issued a technical selection guide for PP/TPO compounders, Tier-1 suppliers and automotive material teams on anti-scratch additives for interior compounds. - The guide says additive selection should not be based only on the lowest initial Delta L. - The company also outlines a screening framework for automotive programs that use PP, PP/TPO and related thermoplastic systems.

The details: - PP and TPO are widely used in interiors because they combine low density, processability, stiffness, impact performance and cost efficiency. - Visible scratches happen because damaged surfaces reflect and scatter light differently from the surrounding area, even when the physical groove is shallow. - Delta L is the common measure for scratch visibility, but applied load, stylus geometry, surface texture, pigment, filler loading, conditioning and test method all affect the result. - Talc-filled PP/TPO is harder to protect because scratch damage can expose lighter filler-rich regions, especially on black, gray and other dark parts. - The guide says talc loading should be one of the first formulation variables reviewed. - Lower friction is a core anti-scratch strategy because it can reduce scratch depth and visible contrast. - Silicone-based technologies and high- or ultra-high-molecular-weight silicone masterbatches are positioned as practical options because they can be compounded directly into the resin. - The guide says anti-scratch performance depends on a balance of surface modification, polymer compatibility and long-term stability. - The six selection factors listed are polymer matrix, talc and filler loading, target scratch test and Delta L, aging and long-term surface stability, VOC/odor/fogging, and gloss/grain/tactile quality. - The guide says scratch resistance should not be improved at the expense of gloss, grain definition, color consistency or hand feel. - The comparison table lists fatty amide slip agents, wax/lubricants, silicone oil, UHMW silicone masterbatch, organically modified siloxane and surface coatings, with migration, compatibility, durability or process cost as the key tradeoffs. - For molded-in-color PP/TPO parts, the guide says masterbatch-based technologies can be attractive because the performance modifier is added during compounding and molding. - A more meaningful evaluation sequence is initial scratch resistance, aging, long-term surface stability, VOC/odor performance and aged scratch resistance. - SILIKE says it conducted internal evaluations covering immediate scratch resistance, long-term scratch-resistance stability, aldehyde/ketone and VOC-related testing, odor evaluation, thermal aging and long-term surface stability. - The guide cautions that those evaluations were based on selected formulations and test conditions, and final suitability must be verified in the customer’s actual formulation. - The selection matrix maps use cases to priorities such as scratch whitening for high-talc PP/TPO, low visible scratch contrast for black door panels, gloss retention for matte dashboards, surface uniformity for fine-grain surfaces, mar resistance for high-touch consoles, long-term stability for high-temperature parts, low VOC for low-emission compounds, PP-Homo compatibility, long-term matrix compatibility for PP copolymer/TPO and test compliance for OEM-qualified projects. - The company’s PP-based silicone anti-scratch portfolio includes LYSI-306, LYSI-306C, LYSI-306H, LYSI-306G and LYSI-906. - The guide positions LYSI-306 as a starting point for general PP/TPO or talc-filled compounds, LYSI-306C for demanding long-term scratch performance in PP copolymer/TPO, LYSI-306H for PP-Homo-rich or compatibility-sensitive formulations, LYSI-306G for non-migration, non-tackiness and thermal stability, and LYSI-906 for low VOC, low odor and high-touch interior surfaces. - A cited internal test snapshot says LYSI-306C at 1.5 wt% in a selected PP/TPO formulation produced Delta L below 1.5 at a 10 N scratch load and met PV3952 and GMW14688 targets in that evaluated formulation. - The guide says those results were formulation- and test-condition-specific. - In one application case, a dark PP/TPO door trim compound with about 20 wt% talc showed an initial Delta L of about 4.1 before modification. - The modified compound used LYSI-306G at 1.5 wt% and reached initial Delta L below 1.5 without changing the intended molded appearance. - After thermal aging, the modified compound kept Delta L below 1.5, while the unmodified control was about 4.4, and no tackiness or visible exudation was reported. - The guide says SILIKE PP-based anti-scratch masterbatches can generally be evaluated within an approximate 0.5 wt% to 5 wt% range, depending on grade and formulation. - The company recommends comparing two or three dosage levels against an untreated control while keeping extrusion, injection molding, mold texture and conditioning constant. - The FAQ says there is no universal best anti-scratch additive for PP automotive interiors and that the right choice depends on matrix, talc loading, elastomer phase, color, surface texture, Delta L target, aging conditions and VOC/odor requirements. - The FAQ also says silicone masterbatches can reduce friction and visible scratch and mar damage, but performance depends on compatibility, dosage, filler loading, surface design and complete formulation. - The guide says scratch resistance should be tested after aging because performance can change after thermal or UV exposure. - The article closes with a request for formulation details so SILIKE can recommend grades and dosage ranges for lab or production trials. - The contact section lists more information on the anti-scratch masterbatch line, the company website at www.siliketech.com and amy.wang@silike.cn.

Between the lines: - The guide is as much about process discipline as it is about additive chemistry. - Its main message is that scratch performance, aging stability and cabin-material compliance have to be judged together, not separately. - That framing matters because a formulation that looks strong in one test can still create visual or regulatory problems once the full compound and real aging conditions are considered.

What's next: - Automotive teams are expected to start with the polymer matrix, talc content and target test method before choosing an additive. - The guide points users toward formulation-specific lab trials rather than a one-size-fits-all product choice. - SILIKE says it can recommend starting grades and dosage ranges once teams provide resin type, filler level, application, current additive, target test, aging requirement, VOC/odor requirement and current surface issue.

The bottom line: - For PP/TPO interiors, the best anti-scratch additive is not the one with the lowest initial Delta L. - It is the one that keeps surface appearance, odor/VOC and aging performance in spec across the full vehicle lifecycle.