1. Safety Risk Prevention

Fire and Explosion Prevention

Storage of Monomers: Monomers such as acrylate (e.g., butyl acrylate, MMA) are flammable and explosive. Storage tanks must be nitrogen-sealed (oxygen content < 0.5%), shielded from light, maintained at a constant temperature below 25°C, and equipped with anti-static devices.

Operational Environment: The reaction workshop must have forced ventilation, use explosion-proof motors/electric equipment, and prohibit open flames.

Toxicity Protection

Monomers such as acrylic acid and styrene are irritating. Personnel must wear gas masks, safety goggles, and chemical-resistant gloves.

Install gas alarms to monitor VOC leakage in real time.

2. Key Points of Process Control

1. Raw Material Quality Control

• Monomer Purity: ≥99.5%; inhibitor (such as MEHQ) content must be accurately measured (usually controlled between 10-50ppm).
• Water Quality Requirements: Deionized water’s conductivity <10μS/cm to prevent metal ions (e.g., Fe²⁺, Cu²⁺) from causing accidental polymerization.

2. Pre-emulsification Process

• Emulsification Uniformity: The stirring speed of the pre-emulsification tank should be ≥1000 rpm (adjust based on scale), with a duration of ≥30 minutes to avoid oil phase stratification.
• Temperature Control: Maintain the temperature of pre-emulsified liquid between 25-40°C to prevent monomer self-polymerization.

3. Polymerization Reaction Control

4. Key Steps in Post-Processing

• Neutralization Adjustment: Use ammonia or NaOH solution to adjust pH to 7.5-8.5 to prevent hydrolysis during storage (operate under <50°C).
• Filtration of Impurities: Use a 100-200 mesh screen to remove gel particles (gel content must be <0.01%).
• Residual Monomers: Add reducing agents (e.g., sodium dithionite) or supplemental initiators to ensure residual monomers <500ppm (environmental regulations).

3. Product Quality and Stability Assurance

Solid Content and Viscosity

• Solid content deviation ≤±1%; viscosity adjusted based on application (e.g., construction emulsions: 500-3000cps).

Latex Particle Size

• Target particle size 80-200nm (measured by laser diffraction), with narrow particle size distribution (PDI <0.1) to enhance film-forming properties.

Freeze-Thaw Stability

• Add antifreeze (e.g., ethylene glycol) at 3-5%, and conduct freeze-thaw cycling tests at -10°C for 24 hours.

4. Environmental Protection and Waste Management

Exhaust Gas Treatment

• Non-condensed monomers treated through activated carbon adsorption or RTO incineration (removal rate >95%).

Wastewater Treatment

• Cleaning water from polymerization reactors containing COD >5000mg/L must undergo coagulation, sedimentation, and biological treatment to meet discharge standards.

Solid Waste Recovery

• Filtered gel residues treated as hazardous waste and entrusted to professional disposal agencies.

5. Common Faults and Prevention

• Gel Formation: Caused by local overheating or stirring failure → Reinforce stirring torque design and install multi-point temperature monitoring.

• Emulsion Breaking and Layering: Improper emulsifier ratio or pH shifts → Optimize HLB value matching in the pre-emulsification phase.

• Abnormal Viscosity: Out of control molecular weight → Accurately control chain transfer agent (e.g., DDM) dosage (0.1-0.5%).