Common Types and Structures of Daily Necessity Composite Bags
Due to the diverse nature of daily necessities, composite bag structures are increasingly specialized. Here are a few typical applications:
1. Shampoo and Shower Gel (Liquid Wash) Bags
These products contain water, surfactants, fragrances, and possibly oils. Packaging requirements include:
Strong barrier properties: Prevents moisture evaporation, maintaining the stability of the contents; locks in fragrances, preventing aroma loss.
Corrosion resistance: Resists chemical attack from the contents.
Strong and durable: Resists punctures and crushing during transportation and shelf placement.
Typical Structure: PET / AL / PE
Outer Layer (PET): Provides excellent printing quality, high strength, and abrasion resistance.
Middle Layer (AL - Aluminum Foil): Provides the strongest barrier to moisture and oxygen, provides complete light protection, and excellent fragrance retention.
Inner Layer (PE): Provides excellent chemical resistance, excellent heat-sealing properties, and is safe and non-toxic.
Development Trend: For environmental reasons and cost reduction, the PET/VMPET/PE structure is now widely used. This structure replaces some aluminum foil with aluminized film. This structure meets most needs while being easier to recycle (an all-plastic structure).
2. Laundry Detergent and Liquid Laundry Detergent (powder and strong chemical) Bags
These products present greater packaging challenges:
Moisture Resistance: Laundry detergents are highly susceptible to moisture absorption and caking.
Leakage Prevention: Powders are very small, requiring excellent heat-sealing strength to prevent leakage; liquids require pressure resistance.
Chemical Resistance: Requires resistance to corrosion from strong alkaline components.
Typical Structure:
Laundry Detergent Bags: BOPP/VMPET/PE or BOPP/PE. The outer BOPP layer offers beautiful printing and moisture resistance, while the inner PE layer offers excellent heat-sealability and effective moisture resistance. For high-end products, an aluminized layer (VMPET) is added to enhance moisture resistance and barrier properties.
Washing Powder Bags: These are typically thicker, with common constructions of PET/PE or NY (nylon)/PE. Nylon offers better puncture and crush resistance.
3. Skincare and cosmetics (creams) packaging bags
These products have the highest packaging requirements, almost on par with, or even higher than, high-end food packaging:
High barrier: Prevents oxidation and inactivation of active ingredients in the cream (such as vitamins and plant extracts).
Fragrance preservation: Maintains the product's unique fragrance.
Light protection: Prevents light-induced deterioration of ingredients.
Aesthetics: Requires extremely high printing quality to reflect the brand's premium positioning.
Typical structures:PET/AL/PE
High-end: PET/VMPET/CPP or PET/EVOH/PE. Using EVOH (ethylene vinyl alcohol copolymer), a transparent, high-barrier material, effectively blocks oxygen like aluminum foil while showcasing the product's inherent texture.
4. Pet Food and Cat Food Bags
This is a very unique category, combining the characteristics of both food and daily necessities, posing extremely stringent requirements:
Extremely high barrier properties: Preserving the freshness and flavor of pet food ("palatability" is crucial).
Extremely strong: Pet food is often heavy and has sharp edges (such as bones), requiring packaging to be extremely puncture- and tear-resistant.
Aroma preservation: The rich meaty aroma must be locked in.
Typical structure: Typically a complex structure of four or more layers, for example:Outer layer (PET) / Middle layer (NY) / Barrier layer (AL) / Inner layer (PE)
NY (nylon) layer: Provides unparalleled puncture and impact resistance.
These bags are typically very thick, feel hard, and are difficult to rub to produce any sound.
