Container House Desiccant

The desiccant for container houses should be selected comprehensively based on the transportation environment, type of goods, and transportation duration. The core principle is to control the humidity inside the container to prevent the goods from getting damp, mildewing, or being damaged.

1. Selection of Desiccant Types

1. Calcium Chloride Desiccant

   • High Moisture Absorption: It can absorb more than 300% of its weight in moisture. After absorbing moisture, it turns into a gel-like substance with no risk of liquid leakage, making it suitable for high-humidity environments (such as maritime shipping containers).
   • Applicable Scenarios: For shipping from Zhongshan to Christchurch (with a voyage of 25-35 days, where the humidity inside the container may reach saturation), it is especially suitable for moisture-sensitive items like textiles and electronic products.
   • Representative Products: TOPSORB container desiccant, AbsorGel® Sheet sheet desiccant.

2. Silica Gel Desiccant

   • Physical Stability: Its shape remains unchanged after absorbing moisture, with no dust pollution, making it suitable for precision instruments or goods sensitive to dust.
   • Applicable Scenarios: For electronic products, optical equipment, etc. However, its moisture absorption rate is relatively slow, and it needs to be combined with other measures to deal with long-term high-humidity environments.
   • Representative Products: Chenrong CR-230704 silica gel desiccant (1kg per string).

3. Montmorillonite Desiccant

   • Continuous Moisture Absorption: It has a slow but continuous moisture absorption rate, suitable for fibrous items like books and clothing, and can cover the entire transportation period.
   • Limitations: Its moisture absorption rate is relatively low (about 20%-30%), and the dosage needs to be increased or used in combination with other desiccants.

2. Calculation of Desiccant Dosage

• Standard Dosage: Calculate based on 0.3% to 0.5% of the internal volume of the container. For example, a 20-foot container (with a volume of about 33 cubic meters) requires 100-165 grams of desiccant per cubic meter, with a total dosage of about 33-50 kilograms.
• Adjustment Principles:
  • The longer the voyage and the higher the humidity, the more the dosage needs to be increased;
  • For goods with high moisture absorption (such as wood and textiles), the dosage needs to be increased;
  • For containers with poor sealing, an additional 10%-20% of the dosage is required.

3. Supporting Moisture-Proof Measures

1. Container Pre-treatment:
   • Check if the container has any damage or air holes and seal all gaps;
   • Containers with a wooden floor moisture content exceeding 20% need to be replaced or dried.
2. Goods Packaging:
   • The moisture content of wooden furniture should be reduced to 8%-10% to avoid quarantine issues when entering New Zealand;
   • Use heat-treated or fumigated pest-free plywood to prevent secondary quarantine.
3. Hanging Position:
   • The desiccant should be hung on the iron rings on the inner side of the container wall, avoiding direct contact with the goods;
   • For a 20-foot container, hang 4-6 strips, and for a 40-foot container, hang 8-12 strips (taking TOPSORB products as an example).

4. Precautions

• Environmental Requirements: Choose desiccants that comply with ROHS and REACH standards (such as products from Shenzhen Chunwang) to avoid contaminating the goods;
• Expiry Date: The shelf life of desiccants is usually 1-2 years, and they should be used within the expiry date;
• Monitoring: For long-term transportation, humidity indicator cards can be used in combination to monitor the humidity inside the container in real-time.