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Discover 15 types of packaging bag material structures, their design rationale, and functional benefits. Learn how to choose the right packaging for your products.
A Comprehensive Overview of Various Packaging Bag Material Structures
This article summarizes the material structures, functional design requirements, and other requirements for different types of packaging bags. Absolutely worth it!
1. Retort Bag Material Structure:
Packaging Requirements: For packaging meat, poultry, etc., the packaging must have excellent barrier properties, be resistant to bone punctures, and withstand sterilization without breaking, cracking, shrinking, or odor during retort.
Design Structure:
Transparent: BOPA/CPP, PET/CPP, PET/BOPA/CPP, BOPA/PVDC/CPP
PET/PVDC/CPP, GL-PET/BOPA/CPP
Aluminum Foil: PET/AL/CPP, PA/AL/CPP
PET/PA/AL/CPP, PET/AL/PA/CPP
Design Rationale:
PET: High temperature resistance, good rigidity, good printability, and high strength.
PA: High temperature resistance, high strength, flexibility, good barrier properties, and puncture resistance.
AL: Optimal barrier properties and high temperature resistance. CPP: High-temperature retort grade, with excellent heat-sealability, non-toxic and odorless.
PVDC: High-temperature barrier material.
GL-PET: Ceramic vapor-deposited film, with excellent barrier properties and microwave permeability.
Select the appropriate structure for the specific product. Transparent bags are mostly used for retort, while AL foil bags can be used for ultra-high-temperature retort.
2. Material Structure of Puffed Snack Bags:
Packaging Requirements: Oxygen and water barrier, light protection, oil resistance, aroma preservation, scratch-resistant appearance, vibrant colors, and low cost.
Design Structure: BOPP/VMCPP
Design Reasons: Both BOPP and VMCPP are scratch-resistant, and BOPP has excellent printability and high gloss. VMCPP has excellent barrier properties, aroma preservation, and moisture resistance. CPP also has good oil resistance.
3. Material Structure of Doenjang (Soybean Paste) Bags:
Packaging Requirements: Odorless, tasteless, low-temperature sealing, resistance to seal contamination, excellent barrier properties, and reasonable price. Design Structure: KPA/S-PE
Design Reasoning: KPA offers excellent barrier properties and good toughness. It has a strong bond with PE, resists bag breakage, and offers excellent printability. Modified PE is a blend of various PE materials (co-extruded), has a low heat-sealing temperature, and is highly resistant to seal contamination.
4. Biscuit Packaging Bag Material Structure:
Packaging Requirements: Excellent barrier properties, strong light-blocking properties, oil resistance, high strength, odorlessness, and scratch-resistant packaging.
Design Structure: BOPP/EXPE/VMPET/EXPE/S-CPP
Design Reasoning: BOPP offers excellent rigidity, printability, and cost.
VMPET offers excellent barrier properties, shields against light, oxygen, and water.
S-CPP offers excellent low-temperature heat sealing and oil resistance.
5. Milk Powder Packaging Material Structure:
Packaging Requirements: Long shelf life, aroma and flavor preservation, resistance to oxidation and deterioration, and moisture absorption and caking.
Design Structure: BOPP/VMPET/S-PE
Design Reasoning: BOPP offers excellent printability, gloss, strength, and reasonable price. VMPET offers excellent barrier properties, light protection, good toughness, and a metallic luster. It is best to use reinforced PET coated with aluminum and a thick AL layer. S-PE offers excellent anti-pollution sealing and low-temperature heat sealing properties.
6. Green Tea Packaging Bag Material Structure:
Packaging requirements: Prevent deterioration, discoloration, and flavor change, specifically preventing oxidation of the protein, chlorophyll, catechin, and vitamin C contained in green tea.
Design Structures: BOPP/AL/PE, BOPP/VMPET/PE, KPET/PE
Design Reasons: AL foil, VMPET, and KPET all offer excellent barrier properties against oxygen, water vapor, and odors. AK foil and VMPET also offer excellent light protection. The product is reasonably priced. 7. Edible Oil Packaging Bag Material Structure:
Packaging Requirements: Anti-oxidative deterioration, good mechanical strength, high burst resistance, high tear strength, oil resistance, high gloss, and transparency.
Design Structures: PET/AD/PA/AD/PE, PET/PE, PE/EVA/PVDC/EVA/PE, PE/PEPE
Design Rationale: PA, PET, and PVDC offer excellent oil resistance and high barrier properties. PA, PET, and PE offer high strength. The inner PE layer is a special PE that resists seal contamination and provides a high airtight seal.
8. Milk Film Material Structure:
Packaging Requirements: Good barrier properties, high burst resistance, light-shielding properties, good heat-sealing properties, and reasonable price.
Design Structure: White PE/white PE/black PE
Design Rationale: The outer PE layer offers high gloss and mechanical strength. The middle PE layer provides strength. The inner layer is a heat-sealing layer, offering light-shielding, barrier, and heat-sealing properties. 9. Ground Coffee Packaging Bag Material Structure:
Packaging requirements: Anti-water absorption, anti-oxidation, resistant to product lumps after vacuuming, and retaining the volatile, easily oxidized coffee aroma.
Design Structure: PET/PE/AL/PE, PA/VMPET/PE
Design Reasoning: AL, PA, and VMPET offer excellent barrier properties, including water and gas barriers, while PE offers excellent heat sealing properties.
10. Chocolate Packaging Bag Material Structure:
Packaging requirements: Excellent barrier properties, light protection, attractive printing, and low-temperature heat sealing.
Design Structure: Pure Chocolate: Varnish/Ink/White BOPP/PVDC/Cold Sealing Glue
Nut Chocolate: Varnish/Ink/VMPET/AD/BOPP/PVDC/Cold Sealing Glue
Design Reasoning: PVDC and VMPET are both high-barrier materials, and cold sealing glue can be sealed at extremely low temperatures, preventing heat from affecting the chocolate. Nuts contain a high amount of oil, which is prone to oxidation and deterioration, so an oxygen barrier layer has been added to the packaging. 11. Beverage Packaging Bag Material Structure:
Packaging Requirements: Acidic beverages require a pH value <4.5, pasteurization, and general barrier properties.
Neutral beverages require a pH value >4.5, sterilization, and high barrier properties.
Design Structure:
Acidic beverages: PET/PE (CPP), BOPA/PE (CPP), PET/VMPET/PE
Neutral beverages: PET/AL/CPP, PET/AL/PA/CPP, PET/AL/PET/CPP, PA/AL/CPP
Design Rationale: For acidic beverages, PET and PA offer good barrier properties and are pasteurization-resistant, extending shelf life due to their acidity. For neutral beverages, AL offers the best barrier properties, and PET and PA are high-strength and high-temperature sterilization-resistant.
12. Liquid Detergent 3D Bag Material Structure:
Packaging Requirements: High strength, impact resistance, burst resistance, good barrier properties, rigidity, stress crack resistance, and a good seal. Design Structure:
① 3D: BOPA/LLDPE; Bottom: BOPA/LLDPE.
② 3D: BOPA/reinforced BOPP/LLDPE; Bottom: BOPA/LLDPE.
③ 3D: PET/BOPA/reinforced BOPP/LLDPE; Bottom: BOPA/LLDPE.
Design Rationale: The above structure offers excellent barrier properties and high material rigidity, making it suitable for 3D packaging bags. The bottom layer is flexible and suitable for processing. The inner layer is modified PE, which has excellent resistance to seal contamination. Reinforced BOPP increases the material’s mechanical strength and barrier properties. PET improves its water resistance and mechanical strength.
13. Aseptic Packaging Cover Material Structure:
Packaging Requirements: Sterile during packaging and use.
Design Structure: Coating/Alpha Alcohol/Peel Layer/MDPE/LDPE/EVA/Peel Layer/PET.
Design Rationale: The PET is a sterile protective film that is peelable. Upon entering the aseptic packaging area, the PET is removed to reveal the sterile surface. The Al foil peel layer is removed when the customer consumes the product. Pre-punch drinking holes in the PE layer, revealing the drinking holes when the AL foil is removed. AL foil is used for high barrier properties. MDPE offers excellent rigidity and thermal adhesion to AL foil, while LDPE is inexpensive. The inner EVA layer has a VA content of 7%. Vatage content greater than 14% is not permitted for direct food contact. EVA also offers excellent low-temperature heat sealing resistance and seal contamination resistance.
14. Pesticide Packaging Bag Material Structure:
Packaging Requirements: Because pesticides are highly toxic and pose a serious threat to human and environmental safety, the packaging requires high strength, excellent toughness, impact and drop resistance, and a good seal.
Design Structure: BOPA/VMPET/S-CPP
Design Rationale: BOPA offers excellent flexibility, puncture resistance, strength, and printability. VMPET offers high strength and barrier properties, allowing for the use of thickened coatings. S-CPP provides heat sealing, barrier properties, and corrosion resistance, and is made from a ternary copolymer of PP. Alternatively, a multi-layer co-extruded CPP containing high-barrier EVOH and PA layers can be used. 15. Heavy-Duty Packaging Bag Material Structure:
Packaging Requirements: Heavy-duty packaging is used for agricultural products such as rice and beans, and chemical products (such as fertilizer). Key requirements include strength, toughness, and necessary barrier properties.
Design Structure: PE/plastic fabric/PP, PE/paper/PE/plastic fabric/PE, PE/PE
Design Rationale: PE provides sealing properties, flexibility, and drop resistance, while the plastic fabric offers high strength.
