According to the technical data of Guoli Chemical, the core competitive advantage of polyethylene glycol PEG-600 lies in its achievement of an ideal balance in **molecular weight, physical form, and performance parameters**, making it the most versatile "all-rounder" choice with optimal comprehensive performance in multiple key application areas, especially in the pharmaceutical and personal care industries.
Detailed explanation:
PEG series products are classic non-ionic surfactants. Different molecular weight grades determine the morphological changes from liquid, semi-solid to solid, as well as differences in key properties such as hygroscopicity, viscosity, and solubility. The advantage of Guoli Chemical PEG-600 stems precisely from its position in this "middle ground."
### 1. Unique Advantages of Physical Form
- **Compared to low molecular weight products (e.g., PEG-200, PEG-300, PEG-400)**: These products are viscous liquids at room temperature (e.g., the viscosity of PEG-400 at 40°C is about 13-17 mm²/s, much lower than PEG-600). The physical form of PEG-600 has advantages. At room temperature (15~25°C), PEG-600 is a **colorless to slightly yellow transparent liquid or semi-solid**. This state allows it to be easily handled and mixed like a liquid when heated, while providing a certain consistency and structural support to the formulation upon cooling, which is unachievable with pure liquid PEG.
- **Compared to high molecular weight products (e.g., PEG-800, PEG-2000)**: High molecular weight PEG is a waxy solid at room temperature and typically requires hot melting for use, making the process more complex. PEG-600 has moderate viscosity (low shear viscosity 100-150 mPa·s at 25°C), allowing operation at low temperatures with lower energy consumption and broader process adaptability.
### 2. Balance of Core Performance Parameters
The key technical indicators of PEG-600 determine its balanced performance across multiple applications.
| Key Performance | PEG-600 (Guoli Chemical) | Advantage Description |
| :--- | :--- | :--- |
| **Hydroxyl value (mg KOH/g)** | **178-196** | **Moderate reactivity**. It retains sufficient reaction sites for subsequent modification such as esterification (better than high molecular weight PEG with low hydroxyl value), while not being too difficult to control due to excessively fast reactions. |
| **HLB value** | **19** | **Extremely strong hydrophilicity**. This value is much higher than most non-ionic emulsifiers (usually 8-16), making its solubilization and moisturizing capabilities very prominent. |
| **Cloud point of 1% aqueous solution** | **>100°C** | **Good high-temperature stability**. Compared with some non-ionic surfactants with low cloud points, PEG-600 does not precipitate and lose efficacy due to the "cloud point" phenomenon in high-temperature processes (e.g., high-temperature leveling in textiles). |
| **Solubility** | **Easily soluble in water, ethanol, acetone** | **Broad formulation compatibility**. Whether in a pure water system or a pharmaceutical or coating formulation containing organic solvents, it can be easily dissolved, which many specialized emulsifiers lack. |
| **Moisturizing property** | **Hygroscopic** | **Core capability as a humectant**. The chain length of PEG with molecular weight 600 can effectively bind water molecules without causing an overly strong film-forming sensation like high molecular weight PEG, providing a refreshing and moist skin feel. |
| **Safety** | **Non-hazardous, non-irritating to skin** | **Foundation for application fields**. In animal tests, it is non-irritating to skin, enabling its safe use in direct human contact pharmaceutical areas such as ointments, suppositories, dropping pills, and injection solubilization, as well as long-lasting cosmetics like creams and lotions, an advantage that many industrial-grade surfactants cannot match. |
### 3. Breadth and Depth of Application Fields
It is precisely the above balanced advantages that give PEG-600 unparalleled application breadth:
- **Pharmaceutical Field**: As an **ointment base**, its water solubility makes it easier to spread and clean than oil-based bases like petrolatum; as a **suppository base**, it quickly dissolves in body fluids and releases the drug; as a **solid dispersion carrier for dropping pills**, it effectively improves the bioavailability of poorly soluble drugs. Low molecular weight PEG has insufficient moisturizing capacity, while high molecular weight PEG has slow hydration and dissolution rates. Only PEG-600 achieves the optimal balance between rapid release and formability due to its molecular weight and form.
- **Personal Care Products**: Compared with the sticky feeling of low molecular weight PEG, PEG-600 as a **humectant** provides a more lasting moisturized skin feel; as an **emulsion stabilizer**, it significantly increases the viscosity of the water phase and enhances the interfacial film strength to prevent emulsion stratification, with better thickening and stabilizing effects than PEG-400.
- **Industrial Field**: In **ceramic slurries**, the molecular chain length of PEG-600 is sufficient to form an effective steric stabilization layer on the particle surface, preventing agglomeration and obtaining slurries with high solid content and high fluidity, with better effects than short-chain PEG; as a **rubber mold release agent** and **metalworking fluid lubricant**, its moderate viscosity and inverse solubility provide a good balance of lubrication and cooling, with better processability than solid PEG.
**Application Recommendations**
- **Pharmaceutical suppositories/ointments**: Recommended dosage 5-30%, compounded with PEG-400 or PEG-4000 as needed according to desired consistency.
- **Cosmetic moisturizing essence**: Recommended dosage 1-5%, can be used synergistically with glycerin, sodium hyaluronate, etc. for moisturizing.
- **Ceramic dispersant**: Add 0.2-1.0% by dry weight of powder to significantly reduce slurry viscosity.
**Precautions**
- **Storage**: PEG-600 is hygroscopic; it must be sealed and stored in a cool, dry place. It will solidify into a semi-solid or solid at low temperatures; this is a physical change. Before use, gently heat in a warm water bath to melt and mix evenly; product quality is not affected.
- **Safety**: Non-irritating to skin, but safety glasses should still be worn during operation to prevent minor eye irritation.
- **Prohibitions**: Avoid storage together with strong oxidizing agents (e.g., peroxides, permanganates).
