Polyethylene glycol PEG-4000/6000 is essentially a low-toxicity non-hazardous substance, but due to its dual characteristics of strong hygroscopicity and combustible dust, strict precautions must be taken against the two core risks of moisture absorption and dust explosion during use.
Detailed Description
Polyethylene glycol PEG-4000/6000 (CAS No.: 25322-68-3) is a non-ionic high molecular polymer produced by Guoli Chemical. It appears as a white waxy solid or granules at room temperature, with a molecular weight range of approximately 3400-6600. The acute oral toxicity LD50 of this product is greater than 5000 mg/kg, classifying it as a practically non-toxic substance, and it is not classified as a dangerous good according to the GHS classification standard. However, this does not mean it can be handled carelessly—the key to its safe use lies in full awareness and management of physical form risks.
First, this product has strong hygroscopicity. Exposure to humid air will cause it to rapidly absorb moisture, leading to caking, deterioration, and even microbial growth. Once moisture absorption occurs, it not only affects usage effectiveness (e.g., failure in precision applications such as pharmaceutical excipients or textile lubrication) but may also cause pressure changes inside the packaging container. Therefore, the container must be kept sealed throughout use, closed immediately after each withdrawal, and the relative humidity of the working environment should be controlled as much as possible below 60%.
Second, and most often overlooked, is a severe risk: fine dust of PEG-4000/6000 suspended in the air at a certain concentration can form explosive mixtures. Its dust explosion class is St1, and the minimum ignition temperature of the dust cloud is greater than 400°C. This means that operations such as cutting, crushing, sieving, and feeding that may generate dust must be kept away from all ignition sources (open flames, electrical sparks, electrostatic discharge, hot surfaces) and be equipped with effective local exhaust ventilation and dust collection systems.
Technical Parameters
| Parameter | Specification |
|---|
| Appearance | White waxy solid or granules |
| Active Content | ≥99% |
| Moisture | ≤1.0% |
| Melting Range | 50~63℃ |
| Flash Point (Open Cup) | ＞240℃ |
| Dust Explosion Class | St1 |
| Minimum Ignition Temperature of Dust Cloud | ＞400℃ |
| Acute Oral Toxicity LD50 | ＞5000 mg/kg (Rat) |
| pH (5% Aqueous Solution) | 4.5~7.5 |
| Hygroscopicity | Strong |
Application Recommendations
Given the multifunctional properties of PEG-4000/6000, its applications span multiple industries including pharmaceuticals, daily chemicals, textiles, and rubber. However, operational precautions vary depending on the specific application:
- Pharmaceutical and Daily Chemical Fields: When used as an ointment base, suppository base, or toothpaste humectant, moisture content must be strictly controlled. The melting temperature is recommended not to exceed 80°C to avoid molecular chain degradation or discoloration due to prolonged heating. The production environment should meet the required cleanliness levels.
- Textile and Papermaking Fields: When used as an antistatic lubricant or coating lubricant, the aqueous solution should be prepared and used immediately to prevent spoilage due to microbial growth during storage. The typical use concentration is 0.5%~5%, and the optimal amount should be determined through small-scale tests based on the specific process.
- Rubber and Plastic Processing: When used as a mold release agent, it can be applied by direct brushing or spraying. If used in molten state, temperature control is necessary (melting point 50~63°C) to avoid exceeding the flash point. When used as an internal additive dispersant, the recommended dosage is 0.5%~3% of the total formulation.
- Metalworking Quenching Fluids: As a component of water-based quenching media, it is recommended to first dissolve in hot water to prepare a concentrated solution, then dilute to the desired concentration. The concentration is typically adjusted within the range of 5%~20% depending on the required quenching cooling rate.
Precautions
Prohibited Actions:
- Strictly prohibit any ignition source (smoking, welding, cutting, exposed heating elements, etc.) in work areas with suspended dust
- Strictly prohibit using direct water streams to clean up spills or using compressed air to blow down dust deposits—this will raise a dust cloud and create explosive conditions
- Strictly prohibit storing or coming into contact with strong oxidizers (peroxides, potassium permanganate, concentrated nitric acid, etc.)
- Strictly prohibit directly adding moisture-caked product into high-temperature melting equipment to avoid local overheating hazards
Personal Protective Equipment Requirements:
- Respiratory protection: When dust exposure is possible, wear an FFP2 or higher-grade dust mask
- Hand protection: Wear chemical protective gloves such as nitrile rubber. Apply hand cream after prolonged operation to prevent skin drying.
- Eye protection: Wear chemical safety goggles to prevent solid particles from splashing into eyes and causing mechanical irritation.
Storage and Handling:
- Storage temperature: Store in a cool, dry place at 10~30°C with relative humidity <60%
- Keep containers sealed. Use promptly after opening, and reseal remaining material for storage
- All equipment and containers must be reliably grounded to prevent static electricity buildup that could cause dust flash fires
- Stacking height must comply with local safety regulations to prevent tipping that could cause packaging damage and dust release
Emergency Treatment Points: For skin contact, wash with soap and water; for eye contact, flush continuously with plenty of water for at least 15 minutes while lifting eyelids; collected spilled material using antistatic, non-sparking tools; residual material can be flushed with water but adequate ventilation must be maintained to prevent water mist from carrying dust and forming an explosive atmosphere; in case of fire, use water mist, dry powder, or carbon dioxide. Do not use direct water streams on piled dust.
