Description

3,9-Dimethyl-2,4,8,10-Tetraoxa-3,9-Diphosphaspiro[5.5]Undecane 3,9-Dioxide is a high-purity, organophosphorus compound with a unique spirocyclic structure, serving as a highly effective halogen-free flame retardant and thermal stabilizer. Its primary value lies in enhancing the fire safety and thermal-oxidative stability of various polymer matrices without compromising mechanical properties or generating corrosive or toxic smoke. This product is essential for manufacturers in the plastics, electronics, and construction industries seeking to meet stringent global safety and environmental regulations.

Application

• Flame Retardant for Engineering Plastics: Imparts excellent flame retardancy to polyamides (PA), polyesters (PBT, PET), polycarbonates (PC), and their blends, particularly in electrical and electronic components.
• Thermal Stabilizer for Polymers: Acts as a processing stabilizer to prevent degradation and maintain color stability in high-temperature polymer processing.
• Additive for Polyurethane Foams: Used in rigid and flexible PU foams for furniture, automotive interiors, and insulation to improve fire resistance.
• Synergist in Flame Retardant Formulations: Often combined with nitrogen-based compounds (e.g., melamine derivatives) to create highly efficient, synergistic intumescent flame retardant (IFR) systems.
• Cable and Wire Coating: Provides critical flame retardancy for insulation and jacketing materials in building wires, communication cables, and automotive wiring.
• Composite Materials: Enhances the fire safety profile of glass-fiber reinforced composites used in transportation and construction applications.

Basic Information

Item	Details
Product Name	3,9-Dimethyl-2,4,8,10-Tetraoxa-3,9-Diphosphaspiro[5.5]Undecane 3,9-Dioxide
CAS No.	3001-98-7
Molecular Formula	C7H14O6P2
Molecular Weight	256.13 g/mol
Synonyms	Bis(neopentylene glycol) diphosphonate; Neopentyl glycol diphosphonate; Spirocyclic pentaerythritol bisphosphonate; SPD; FR-SPD; 3,9-Dimethyl-3,9-dioxo-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane; PEPA (common abbreviation); Halogen-free phosphonate flame retardant
EINECS	221-108-5

Quality Control

Every batch of our 3,9-Dimethyl-2,4,8,10-Tetraoxa-3,9-Diphosphaspiro[5.5]Undecane 3,9-Dioxide is manufactured under a strict quality management system to ensure batch-to-batch consistency and high performance. Our quality control protocols include advanced analytical techniques to verify purity, chemical structure, and thermal properties. A comprehensive Certificate of Analysis (COA) detailing assay, impurity profile, and key physical parameters is provided with each shipment to support your quality assurance and regulatory compliance needs.

Storage

Preserve in a tightly closed container, protected from light. Store in a cool, dry, and well-ventilated area at room temperature (15-25°C). Keep away from strong oxidizing agents and moisture to maintain product integrity.

Specification

Item	Specification
Appearance	White crystalline powder
Identification (IR)	Conforms to structure
Assay (HPLC)	≥ 98.5%
Melting Point	205 - 215 °C
Phosphorus Content	23.8 - 24.2 %
Volatile Matter	≤ 0.5 %
pH (10% suspension)	5.0 - 7.0
Particle Size (D50)	≤ 20 μm (customizable)

Note: Specifications can be tailored. Please contact us for the detailed technical data sheet of a specific grade.