By [email protected] — Charting the depths of expertise
Core Functions of Packaging
Packaging for cleanroom consumables like cleanroom wipes and nonwoven wipes generally consists of double-bagging in high-cleanliness PE bags, with a soft LDPE inner bag and a high-strength HDPE outer bag. Its primary purpose is to protect the product from various contaminants and damage, ensuring it maintains the required cleanliness and performance during transport, storage, and use.
Core functions include:
Preventing Particulate and Microbial Contamination: This is the most basic function of packaging. It requires the use of low-linting bags with excellent seal integrity. The heat-seal strength must be high enough to withstand mechanical stress during handling and transport, while avoiding excessive heat that could cause material degradation and particle generation.
Preventing Chemical Contamination: The packaging material must be chemically stable. It should not release volatile organic compounds (VOCs) or have extractables (IC, NVR) that could migrate to the cleanroom wipe during storage. This prevents interactions and the transfer of chemical residues to the product surface.
Facilitating Transfer Across Cleanliness Zones: The double or triple-bagging design serves as a transfer system for moving between different cleanliness zones. When materials enter the cleanroom, the outer bag, which has been contaminated during transport, is removed in a lower-class area like a gowning room or airlock. Subsequently, the product, now only in its clean inner bag, is passed into the higher-class core work area. Finally, the inner bag is opened by the operator at the point of use. This standardized "staged removal" process effectively isolates external contaminants from the core area and is a critical step in preventing cross-contamination and maintaining the clean environment.
Selection of Packaging Materials
Common Packaging Material Abbreviations
| Abbreviation | English Name | Chinese Name | Key Properties & Packaging Applications |
|---|---|---|---|
| PE | Polyethylene | 聚乙烯 | The most fundamental and widely used plastic in packaging. It forms the basis of most cleanroom bags and is mainly divided into LDPE and HDPE based on density. |
| LDPE | Low-Density Polyethylene | 低密度聚乙烯 | Soft texture, high transparency, and easy to heat-seal. It is the most common material for cleanroom PE bags, especially suitable as the inner layer in direct contact with the product. |
| HDPE | High-Density Polyethylene | 高密度聚乙烯 | Harder texture, semi-transparent matte appearance, with much higher strength and puncture resistance than LDPE. Often used as the outer bag for stronger physical protection. |
| CPE | Chlorinated Polyethylene | 氯化聚乙烯 | Produced by the chlorination of HDPE. Has rubber-like elasticity, and is resistant to weathering, oil, acids, and alkalis. Sometimes used for gloves or bags with a special matte finish in cleanrooms, but less common than PE or PA. |
| EPE | Expandable Polyethylene | 珍珠棉 | A foam material made by physically foaming LDPE. Its core function is cushioning and shock absorption, used for making packaging liners, positioners, and dividers. |
| PP | Polypropylene | 聚丙烯 | Harder texture, better heat resistance than PE (can withstand >100°C), and high strength. Often used as the inner or outer layer in retortable composite bags. |
| CPP | Cast Polypropylene | 流延聚丙烯 | A special type of PP. Has excellent transparency and gloss, and superior heat-sealing properties. It is a common inner heat-seal layer in composite bags like foil or nylon bags. |
| PA / NY | Polyamide / Nylon | 聚酰胺 / 尼龙 | These two terms refer to the same material. It has excellent toughness, is highly resistant to puncture and abrasion, has good gas barrier properties, and is the primary material for vacuum bags. |
| PET / APET | Polyethylene Terephthalate | 聚对苯二甲酸乙二醇酯 | Commonly known as "polyester resin." It offers high hardness, flatness, and good printability, with stable dimensions. Typically used as the outermost layer of composite bags (like foil or shielding bags) for support, protection, and printing. APET has higher transparency and superior low-temperature toughness and impact resistance, often used in food and pharmaceutical packaging. |
| AL | Aluminum | 铝（箔） | A metal material. Provides superior barrier properties, offering 100% protection against moisture, oxygen, light, and electromagnetic radiation. It is the absolute core layer that enables the function of aluminum foil bags. |
Common Materials for Inner and Outer Bags
Most packaging for cleanroom wipes and nonwoven wipes consists of PE bags in a double-bagged (inner + outer) design. Triple-bagging is rare (used only when cleanliness requirements are extremely strict). See the table below for more material details:
| Name | Material | Advantages | Disadvantages | Shedding | Application | Relative Cost Index |
|---|---|---|---|---|---|---|
| PE Bag | LDPE | Flexibility, transparency | Lower strength, average barrier | Low | Common inner packaging for cleanroom wipes | 1.2 |
| PE Bag | HDPE | Rigidity, strength, low particle shedding, low cost | Poor transparency, more brittle | Very Low | Common outer/middle packaging for cleanroom wipes (3 layers are rare) | 1.0 |
| PP Bag | PP | Heat resistance (autoclavable), high transparency | Brittle at low temperatures | Low | Applications requiring high-temperature sterilization | 1.5 |
| Nylon Bag | PA+CPE, PA+CPP | Extremely high toughness & abrasion resistance, very low particle shedding | Hygroscopic, higher cost | Very Low | Higher cleanliness and strength needs; better for vacuum sealing | 3.0+ |
Packaging Methods
Common packaging methods for cleanroom wipes and nonwoven wipes:
Double-Bagging: An inner bag plus an outer bag. Heat-Sealing: The standard method of sealing the bag using heat. Vacuum-Sealing: Before heat-sealing, the air is evacuated from the bag and then sealed. This method better protects the product and reduces package volume. Inner Sub-Packaging: For example, four smaller inner bags are packed before being placed into a single outer bag. Another method involves stacking the product into four piles within a single inner bag. Both methods are common for smaller-sized wipes. Presaturation: Wipes are pre-moistened with a specific solvent (e.g., IPA, alcohol, DI water) before packaging to create a ready-to-use wet wipe. The packaging must have an excellent seal to prevent solvent evaporation.
Summary
Choosing the right packaging for cleanroom wipes and nonwoven wipes requires considering several factors:
The cleanliness of the application environment; The characteristics of the wipe, such as size and shape; Selecting packaging materials based on transport distance, storage time, and environmental conditions; Balancing material costs, production efficiency, and shipping costs to achieve the best cost-effectiveness while meeting performance requirements; Ensuring the packaging system complies with relevant regulations and standards, such as GMP and ISO 14644, to avoid compliance risks.
