I. Project Background and Customer Requirements

The customer's product is Fan duct support , TPE needs to be used on the PP substrate. Rubber-coating molding The core demand is clear:

1. Excellent formability Ensure stable and efficient encapsulation molding.
2. Comfortable to the touch The grip area should have a good tactile feel.
3. Cost-effectiveness Control costs while meeting performance requirements.

 

II. Preliminary Plan and Issues

Based on the customer’s emphasis on cost, we initially recommended: Economic-grade material ZN60 Its basic physical parameters are as follows, matching the target hardness:

Test result: NG (Not合格)
Customer feedback on mold trial: ZN60 material   Poor molding   This manifests as incomplete coating and poor bonding strength, making stable production impossible.

III. Solutions and Implementation Process

For the issue of formability, conduct root cause analysis and reselect the materials.

1. Problem Analysis (Engineer’s Perspective) ：
2. Core bottleneck Successful rubber coating primarily depends on the material. Liquidity and Interfacial Adhesion Capability . ZN60's Low melt index (approximately 3 g/10 min) This indicates that the melt has insufficient flowability, making it unable to quickly and thoroughly fill the complex PP skeleton during coating, which results in insufficient glue coverage or poor adhesion.
3. Performance trade-offs : Although ZN60 is... Tensile strength, tear strength, and toughness (elongation) Performs exceptionally well, and Low specific gravity (cost advantage) However, these advantages become ineffective in the face of “the inability to take shape.” The primary contradiction in this case is: Processing performance 。
4. Scheme reselection ：
   We recommended. ZR60-FTJ The comparison of their core physical properties is as follows:
5. Analysis of the Impact of Feature ZN60 (Preliminary Selection) vs. ZR60-FTJ (Final Selection) on Applications Hardness 60±5 A58-60 A Basic support performance is consistent. Melt index: ~3 g/10 min vs. 9 g/10 min—Key difference: ZR60-FTJ exhibits significantly superior flowability, directly addressing the challenges of filling and coating. Tensile strength: 4 ± 1 MPa vs. 3 MPa. ZN60 is stronger, but it’s not critical in this case; the strength of ZR60-FTJ already meets the requirements. Fracture elongation: 500 ± 100% / 240% ZN60 is tougher, but ZR60-FTJ has sufficient elongation and may offer a more “bouncy” rather than “sticky-tough” feel. Specific gravity: 1.09 ± 0.02–1.18 The ZN60 material has lower costs, but after accounting for the overall processing yield, the total cost of ZR60-FTJ is more favorable. Feature Description (General Economy Type) Well-shaped, comfortable to the touch, and economical. ZR60-FTJ formulation is targeted at High-flow overmolding With Tactile sensation Double optimization
6. Test validation ：
   Customer use ZR60-FTJ Test sample.
   Test result: OK (Passed)
7. Formability High fluidity perfectly solves the filling issue, ensuring uniform and robust coating with a wide process window.
8. Hand feel and cost It offers both a comfortable tactile feel and controllable overall costs.

IV. Analysis of the Principles of Success

This case is typical.   Application-oriented, precision-matched performance  。

1. Grasp the principal contradiction. For rubber-coated applications, Liquidity (MI) is a critical process parameter. ZR60-FTJ ensures processing feasibility through its higher melt index (9 vs. 3), which is the cornerstone of the project’s success.
2. Understand performance trade-offs The ZR60-FTJ has “subtracted” in certain mechanical properties (strength, elongation) and density—but that’s precisely what... The necessary and precise trade-offs made to achieve critical high fluidity and optimized handling. Its performance fully meets the end-user’s requirements, with no redundant waste.
3. The formula is highly targeted. The product description—“well-formed and comfortable to the touch”—confirms that its formulation system (including base materials, oils, and additives) is specifically designed for applications such as rubber coating, rather than being a general-purpose solution.

V. Conclusion and Implications

1. Case Conclusion By replacing the general-purpose material ZN60 with the specialized material ZR60-FTJ, we have primarily overcome... Molding defects caused by insufficient liquidity It successfully solved the challenges in the rubber-coating process while simultaneously meeting both the feel and cost requirements.