High-Loading Viscosity Reduction in SMC/BMC: Technical Analysis of Hyperdispersant RD-9779

Product Overview

In the manufacturing of SMC (Sheet Molding Compound) and BMC (Bulk Molding Compound), managing the rheology of highly filled systems is a critical engineering challenge. RD-9779 is a high-performance hyperdispersant composed of a copolymer containing acid groups. Specifically engineered for solvent-based and solvent-free systems, its technical profile makes it a premier alternative to industry benchmarks like BYK-9010. It offers excellent viscosity reduction for inorganic fillers, superior wetting efficiency, and exceptional high-temperature stability.

Core Chemical Mechanism

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  Robust Anchoring: The copolymer contains abundant acid groups that provide high affinity for the surface of inorganic fillers and alkaline pigments.

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  Steric Hindrance: Once adsorbed, the polymer chains create a dense protective layer that prevents particle re-agglomeration and prevents the lapping paste from thickening.

  
  

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  Viscosity Reduction Profile: By optimizing wetting and dispersion, it significantly lowers the system's internal friction, improving fluidity and shortening the grinding cycle.

  
  

Technical Data Comparison

The following data illustrates how RD-9779 matches the specifications required for high-polarity and solvent-based systems compared to industry standards.

Safety & Eco-Friendly Profile (Non-Hazardous)

RD-9779 is designed with a focus on industrial safety and environmental sustainability:

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  Non-Hazardous Classification: According to the Safety Data Sheet, there is no known danger associated with this substance.

  
  

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  Halogen & Heavy Metal Free: The product contains no halogens or heavy metals, making it environmentally friendly.

  
  

  
  

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  Low Toxicity:  classifying it as practically non-toxic.

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  Safety in Operation: There is no evidence that the product is a respiratory sensitizer or a chronic health hazard.

  
  

Application & Dosage Guide

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  Scope of Application: Suitable for all solvent-based coating systems, SMC, BMC, and water-based systems.

  
  

• Recommended Dosage:

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  Inorganic Pigments: 1-5.0%.




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  Fillers (e.g., CaCO3): 0.2-1.0%.




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  Alkaline Carbon Black: 20%-40%.




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  Usage: RD-9779 should be dissolved in the grinding base mixture or diluted with water before adding pigment for grinding.

 Professional FAQ 

Q: I am designing an SMC formulation with high Calcium Carbonate loading. How does RD-9779 perform as a viscosity reducer?

A: RD-9779 provides a superior viscosity reduction profile for all kinds of inorganic fillers. It significantly improves the wetting ability of the base material, allowing you to increase filler loading while improving fluidity and reducing grinding time.

Q: Is RD-9779 safe for large-scale factory environments?

A: Yes, RD-9779 is a safe, eco-friendly additive. It is not classified as a hazardous substance and contains no halogens or heavy metals.  it poses no known chronic health hazards to workers.

Q: Will RD-9779 degrade or cause odors during the high-temperature molding process of BMC?

A: No. The material is stable under moderate high temperatures and pressures. Its decomposition temperature is above 300℃, which far exceeds typical SMC/BMC molding temperatures, ensuring no degradation or harmful emissions during processing.