Composite packaging bag material structure design and application, including food bags and three-dimensional bags

Modern packaging design has been given more creative expansion due to the continuous advancement of materials and technology. This not only affects the function of the packaging but also affects the development and changes in the shape and structure of the packaging. Therefore, Shunxingyuan Packaging, a professional flexible packaging manufacturer, believes that being familiar with various packaging materials and their applications can better design unique packaging.

 

 

 

 

I. Food Packaging

 

 

 

 

1. Retortable pouches

Product Requirements:

Used for packaging meat, poultry, etc., requiring good barrier properties, resistance to bone punctures, and no breakage, cracking, shrinkage, or odor under retorting conditions.

Design Structure:

Transparent type: BOPA/CPP, PET/CPP, PET/BOPA/CPP, BOPA/PVDC/CPP, PET/PVDC/CPP, GL-PET/BOPA/CPP

Aluminum foil type: PET/AL/CPP, PA/AL/CPP, PET/PA/AL/CPP, PET/AL/PA/CPP

Design Rationale:

PET: High temperature resistance, good rigidity, good printability, high strength.

PA: High temperature resistance, high strength, flexibility, good barrier properties, puncture resistance.

AL: Best barrier properties, high temperature resistance.

CPP: High-temperature retort grade, good heat sealability, non-toxic and odorless.

PVDC: High-temperature resistant barrier material.

GL-PET: Ceramic vapor-deposited film, good barrier properties, microwave transparent.

For specific products, choose the appropriate structure. Transparent bags are mostly used for retorting, while AL foil bags can be used for ultra-high temperature retorting.

2. Inflated leisure food

Product Requirements:

Oxygen barrier, water barrier, light protection, oil resistance, aroma retention, crisp appearance, bright colors, low cost.

Design Structure:

BOPP/VMCPP

Design Rationale:

Both BOPP and VMCPP are crisp, BOPP has good printability and high gloss. VMCPP has good barrier properties, aroma retention, and moisture resistance. CPP also has good oil resistance.

3. Soybean paste packaging bag

Product Requirements:

Odorless, low-temperature sealing, anti-seal contamination, good barrier properties, moderate price.

Design Structure:

KPA/S-PE

Design Rationale:

KPA has excellent barrier properties and high toughness, high bonding strength with PE, not easy to break, and good printability. Modified PE is a mixture of various PEs (co-extrusion), with a low heat sealing temperature and strong anti-seal contamination.

4. Biscuit packaging

Product Requirements:

Good barrier properties, strong light shielding, oil resistance, high strength, odorless, crisp packaging.

Design Structure:

BOPP/EXPE/VMPET/EXPE/S-CPP

Design Rationale:

BOPP has good rigidity, good printability, and low cost.

VMPET has good barrier properties, light shielding, oxygen barrier, and water barrier.

S-CPP has good low-temperature heat sealability and oil resistance.

5. Milk powder packaging

Product Requirements:

Long shelf life, aroma and flavor retention, prevention of oxidation and deterioration, and prevention of moisture absorption and caking.

Design Structure:

BOPP/VMPET/S-PE

Design Rationale:

BOPP has good printability, gloss, and strength, and a moderate price.

VMPET has good barrier properties, light shielding, toughness, and metallic luster. Enhanced PET aluminum plating is preferred, with a thick AL layer.

S-PE has good anti-contamination sealing and low-temperature heat sealing.

6. Green tea packaging

Product Requirements:

Preventing deterioration, discoloration, and changes in flavor, i.e., preventing the oxidation of proteins, chlorophyll, chlorogenic acid, and vitamin C contained in green tea.

Design Structure:

BOPP/AL/PE, BOPP/VMPET/PE, KPET/PE

Design Rationale:

AL foil, VMPET, and KPET are all materials with excellent barrier properties, providing good barrier properties against oxygen, water vapor, and odors. AK foil and VMPET also have excellent light shielding properties. The product price is moderate.

7. Edible oil

Product Requirements:

Preventing oxidation and deterioration, good mechanical strength, high burst strength, high tear strength, oil resistance, high gloss, and transparency.

Design Structure:

PET/AD/PA/AD/PE, PET/PE, PE/EVA/PVDC/EVA/PE, PE/PEPE

Design Rationale:

PA, PET, and PVDC have good oil resistance and high barrier properties. PA, PET, and PE have high strength. The inner layer PE is a special PE with good anti-seal contamination and high airtightness.

8. Milk film

Product Requirements:

Good barrier properties, high burst strength, light shielding, good heat sealability, and moderate price.

Design Structure:

White PE/White PE/Black PE

Design Rationale:

The outer layer PE has good gloss and high mechanical strength. The middle layer PE bears the strength, and the inner layer is the heat sealing layer, with light shielding, barrier, and heat sealing properties.

9. Ground coffee packaging

Product Requirements:

Water absorption prevention, oxidation prevention, resistance to hardening of the product after vacuuming, and preservation of the volatile and easily oxidizable aroma of coffee.

Design Structure:

PET/PE/AL/PE, PA/VMPET/PE

Design Rationale:

AL, PA, and VMPET have good barrier properties, water resistance, and gas resistance. PE has good heat sealability.

10. Chocolate

Product Requirements:

Good barrier properties, light shielding, beautiful printing, and low-temperature heat sealing.

Design Structure:

Pure chocolate: Varnish/Ink/White BOPP/PVDC/Cold Seal Adhesive

Nut chocolate: Varnish/Ink/VMPET/AD/BOPP/PVDC/Cold Seal Adhesive

Design Rationale:

PVDC and VMPET are both high-barrier materials. Cold-seal adhesives can seal at very low temperatures, and the heat will not affect the chocolate. Because nuts contain a lot of oil, they are prone to oxidation and spoilage, so an oxygen barrier layer has been added to the structure.

11. Beverage packaging bags

Product Requirements:

The PH value of acidic beverages is <4.5, pasteurized, and generally has barrier properties.

The PH value of neutral beverages is >4.5, sterilized, and requires 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 provide good barrier properties and withstand pasteurization, as acidity extends shelf life. For neutral beverages, AL provides the best barrier properties, while PET and PA offer high strength and withstand high-temperature sterilization.

12. Soy sauce, sauce

Product Requirements:

Requires high strength, long shelf life, oxidation resistance, corrosion resistance, and good sealing against contamination.

Design Structure:

KPA/LLDPE. EVA, BOPA/VMPET/LLDPE. EVA, PET/AL/PET/LLDPE. EVA, PET/VMPET/LLDPE. EVA.

Design Rationale:

KOP, AL, and VMPET are all high-barrier materials with excellent oxygen and water barrier properties. The AL layer is kept at a suitable distance from the inner layer to prevent corrosion. LLDPE and EVA offer good sealing against contamination.

II. Lid Materials

 

 

 

 

1. Easy-peel lids for pudding and jelly

Product Requirements:

Non-toxic, odorless, withstands contents, does not break during transport, good roll, easy to peel, no residue.

Transparent type:

PET/LTS, PET/PET/LTS, BOPA/BOPA/LTS, good barrier properties, no warping, two-layer BOPA type has good tension after sterilization, easy to peel.

Transparent barrier properties:

BOPA/PVDC/BOPA/LTS, BOPA/EVOH/LTS, KPA/PA/LTS, added barrier layer, extended shelf life.

Opaque barrier type:

PET/VMPET/LTS, PET/VMPET/LTS, PET/AL/LTS, PET/AL/PET/LTS, AL/PET/PE/HM. Increased light blocking, high barrier properties.

Developed countries have good transportation and handling conditions, and easy-peel lids designed for children have a heat sealing strength of only 7-12N/. In China, the transportation environment is relatively poor, and the heat sealing strength generally needs to reach 18N/.

2. Boiling sterilization lid materials

Used for sealing liquid packaging containers such as beverage cups and yogurt bottles, PET/AL/CPP. High heat sealing strength, withstands boiling sterilization, metallic luster.

3. Dry food container lid materials

Structure:

Printing layer/AL/PE/HM. Used for puffed foods, instant noodles, etc., with good heat sealing properties with foamed plastics.

4. Aseptic packaging lid materials

Aseptic both during packaging and use.

The structure is:

Coating/AL/Peelable layer/MDPE/LDPE/EVA/Peelable layer/PET.

PET is an aseptic protective film that can be peeled off. When entering the aseptic packaging area, the PET is peeled off to reveal the aseptic surface. The AL foil peelable layer is peeled off by the customer when drinking. The drinking hole is pre-punched on the PE layer, and the drinking hole is revealed when the AL foil is peeled off. The AL foil is used for high barrier properties, MDPE has good rigidity and good heat adhesion to the AL foil, LDPE is inexpensive, and the inner EVA has a VA content of 7%. VA>14% is not allowed to be in direct contact with food. EVA has good low-temperature heat sealing and anti-sealing contamination properties.

III. Liquid Detergent Stand-up Pouches

 

 

 

 

Product Requirements:

High strength, impact resistance, burst resistance, good barrier properties, good rigidity, can stand upright, stress crack resistance, good sealing.

Design Structure:

Stand-up BOPA/LLDPE Bottom BOPA/LLDPE

Stand-up BOPA/Reinforced BOPP/LLDPE Bottom BOPA/LLDPE

Stand-up PET/BOPA/Reinforced BOPP/LLDPE Bottom BOPA/LLDPE

Design Rationale:

The above structures have good barrier properties and high material rigidity, suitable for stand-up pouches, and the bottom is flexible and suitable for processing. The inner layer is modified PE, with good anti-sealing contamination properties.

IV. Composite Tubing Materials

 

 

 

 

As composite tubes for packaging toothpaste, cosmetics, seasonings, and ointments, the requirements for packaging performance are good barrier properties, fragrance retention, oxidation resistance, and light protection. Good printing effect, beautiful appearance, good display effect. Good feel, good texture, wear-resistant exterior, not easily contaminated. Bend resistance, folding resistance, and environmental stress crack resistance are a type of high-demand composite flexible packaging materials.

Common structures of composite flexible packaging are:

PE/AD/AL/AD/PE, PE/Printing/White PE/AD/AL/AD/PE, PE/White PE/Paper/AD/AL/AD/PE, PE/Paper/EMAA/AL/EMAA/PE.

V. Some New Structures:

 

 

 

 

Infusion bags:

BOPA/EVOH/PP

PET/EVOH/PP

Wallpaper:

PEPER/PVC/EVOH

Tofu:

PET/EVOH/BOPA/PP

Nutritional infusion:

PE/EVOH/BOPA/CPP

Tea:

PET/EVOH/PE

BOPP/EVOH/PE

PAPER/PE/EVOH/PE

Steaming lid:

BOPA/EVOH/Easy-peel seal

PET/BOPA/EVOH/BOPA/Easy-peel seal

PET/AL/Coextruded PE

Seasonings:

CPP/PT/AL/CPP

Paper/PVDC

Fruit juice, tomato sauce:

PE/Paperboard/EAA/AL/EAA

Wet wipes:

PET/VMPET/CPP

PET/AL/VMPET/LLDPE

VMPET/CPP

KPET/EVA

Meat products:

NY/PET/CPE

NY/NY/PE

Raw meat:

NY/EVOH/EVA

NY/EVOH/Ionomer