Article Directory
A juice producer plans a twelve-month shelf-life target; an edible-oil packer only needs six. Both ask for a Bag-in-Box (BIB) bag, and both should get the same answer: the film structure decides what is possible. Single-layer polyethylene can hold a low-oxygen-risk liquid for weeks, while a multi-layer film with EVOH can keep the same product fresh for eighteen months. That single choice drives your oxygen barrier, spoilage rate, freight weight, seal reliability and film cost per litre.
A single-layer BIB film consists of one extruded polymer, almost always LDPE or LLDPE. A multi-layer BIB film bonds two or more functional layers so that each layer performs one job: mechanical strength, gas barrier or heat sealing.
Co-extrusion pushes several polymer melts through a single die so they weld together while molten; lamination glues separately cast films together. Either route lets the converter combine a strong outer layer, a thin barrier layer and a food-contact seal layer into one bag film.
One PE layer, typically 60 to 120 microns thick. It seals quickly, costs the least per square metre and is adequate for water, low-acid industrial fluids and short distribution cycles. Its oxygen transmission rate is high, so oxygen-sensitive liquids lose colour and flavour quickly at ambient temperature.
A standard five-layer stack runs: structural PA or PET outside, adhesive tie layers, a central EVOH barrier of 3 to 7 microns, and an inner PE seal layer that welds to the spout. Aseptic grades add nylon and sterilisation-compatible sealants. Every layer exists for a reason: the outer layer absorbs abuse, the middle layer blocks gas, the inner layer seals the fitment.
One polymer does every job.
Each layer has one function.
Barrier performance is the largest measurable difference between the two constructions. A single-layer PE film transmits roughly 1,500 to 2,500 cc of oxygen per square metre per day; a five-layer EVOH film stays below 3 cc. Moisture vapour transmission follows the same pattern, though the gap is smaller.
Typical ambient shelf life by film structure
Horizontal bar chart: typical ambient shelf life for oxygen-sensitive liquids, assuming 20-25 °C storage and correct fitment sealing.
| Structure | Composition | OTR cc/m²/day | Relative film cost | Typical shelf life |
| Single-layer | LDPE / LLDPE | 1,500-2,500 | 1.0x | 3-6 months |
| 3-layer co-ex | PE / tie / PA | 100-300 | 1.3-1.5x | 6-9 months |
| 5-layer barrier | PE / tie / EVOH / tie / PE | 1-5 | 1.6-2.0x | 12-18 months |
| 7-layer aseptic | PA / EVOH / PE aseptic grades | 0.3-1 | 2.2-2.8x | 18-24 months |
Food and beverage lines holding fruit concentrates, syrups or dairy depend on the barrier properties that keep foods and beverages fresh; a single-layer bag cannot protect them at ambient temperature. Hot-filled liquids add another constraint, because the seal layer must also survive the fill temperature.
Multi-layer films also win on handling strength. The outer PA or PET layer absorbs puncture, abrasion and flex-crack stress while the EVOH stays buried and dry. A single-layer PE bag must resist the same abuse with one soft polymer, so it pinholes more often at carton corners and in vibrating truck loads.
Seal integrity follows the same logic. The inner seal layer must weld reliably to the spout during a full production shift and survive warehouse drops. The balance between bag evacuation rate, spout placement and bag geometry is as important as the barrier itself, which is why plant trials matter: films that look identical on paper behave differently on a real filling machine.
The common failure sequence in packaging line audits is not surface barrier failure. It is flex-crack pinholes at folded corners, then fitment leakage. Both are solved by layer count, not by gauge alone.
Multi-layer film costs 30 to 180 percent more per square metre, but the number that matters is cost per litre delivered without spoilage. A five-layer bag adds only a small cost to every thousand litres; one lost pallet of spoiled single-layer juice can erase the savings from hundreds of bags.
Savings also appear beyond the film itself. A composite structure often allows a thinner total gauge, so empty bag weight stays competitive. Fewer rejected bags reduce filling-line downtime, and a lower OTR lets formulators cut preservatives or antioxidants, which buyers increasingly treat as a formulation advantage. For most producers, the single-layer versus multi-layer BIB film decision is really a shelf-life decision in disguise.
Choose the structure from your product's oxygen sensitivity, filling temperature and target shelf life, not from a film catalogue. The table below compresses the common decisions.
| Product | Typical structure | Primary reason |
| Water, non-sensitive beverages | Single-layer | Barrier is not critical |
| Soda syrup and concentrates | 3-5 layer | Oxygen causes browning |
| Tomato and apple concentrate | 5-layer EVOH | Colour and vitamin retention |
| Edible oil and condiments | 5-layer | Oxidation causes rancidity |
| Wine and spirits | 5-7 layer | Low OTR preserves aroma |
| Dairy and liquid egg | 5-7 layer aseptic | Microbial and oxygen control |
| Agrochemical and industrial liquids | Single or 3-layer HDPE | Chemical compatibility over oxygen |
For juice, syrup, dairy, edible oil and liquid egg, the barrier stack is the core of product protection. Production teams often start with food and beverage BIB packaging from Suzhou Jingle Packaging Technology Co., Ltd. because film, fitment and bag geometry are already matched to filling conditions.
Bag-In-Box(BIB) Packaging For Food & Beverage ManufacturersAs China Bag-In-Box(BIB) Packaging For Food & Beverage Manufacturers, Factory, Suzhou Jingle Packaging Technology Co. Ltd. Supply Custom ...View Product →
Agrochemicals, pharmaceutical intermediates, daily chemicals and car fluids care more about chemical resistance and leakproof performance than oxygen. The non-food BIB packaging range uses HDPE-heavy structures that tolerate aggressive formulations during storage and transport.
BIB Packaging For Non-food Products Manufacturers, FactoryWe Are China BIB Packaging For Non-food Products Manufacturers, Factory, Suzhou Jingle Packaging Technology Co. Ltd. Custom Non-food Prod...View Product →
If your target sits between catalogue options, converters can tune layer count without changing bag size. EVOH thickness, nylon percentage and sealant grade are the adjustable variables. The supporting technologies portfolio covers fitment selection, valve sealing and filling compatibility, and engineering teams can run product tests before production. For tea and coffee liquids in particular, the balance between OTR and aseptic shelf life is tight enough that structure changes need real shelf-life data, not estimates.
Custom Bag-In-Box Plastic Valve/Caps/Tube/Taps/Fitments ManufacturersSuzhou Jingle Packaging Technology Co. Ltd. Offer Custom Valve/Caps/Tube/Taps/Fitments For BIB, We Are China Bag-In-Box Valve/Caps/Tube/T...View Product →
If the product changes appearance or aroma within three months in a PE bag at ambient temperature, move to a multi-layer structure. If the target is beyond twelve months, plan for EVOH from the start.
Test three variables before choosing: oxygen sensitivity, filling temperature and target shelf life. Water or low-acid industrial liquids with a six-month target can run single-layer; juice, syrup, oil or dairy with a twelve-month target needs at least a five-layer EVOH structure.
Yes, in most cases. PE alone distorts above 80 °C and the seal area can fail during cooling. A PA or PET outer layer holds dimensional stability at hot-fill temperatures, and aseptic grades are required when fill temperature exceeds 90 °C.
Rarely. Aseptic filling demands high seal integrity plus a reliable barrier over the full distribution window, so most aseptic BIB programs use five to seven layers. Single-layer film suits only low-oxygen-risk products in short ambient cycles.
A thin EVOH layer performs best when protected from moisture and mechanical stress, which is why converters sandwich it between tie and structural layers. The nylon or PET outer layer absorbs flexing during transport, so pinholes stay rare. This is why a five-layer bag outlasts a three-layer bag in real distribution.
Address
No. 758 Longqiao Road, Wujiang Economic Development Zone, Suzhou, Jiangsu, China, 215200
cs3@suzhoujingle.com ( Ellie Li )
sales-sea@suzhoujingle.com ( Alex Too )
billhe@suzhoujingle.com ( Bill He )
kennyyan@suzhoujingle.com ( Kenny Yan )
Phone
+86-51263068181
Fax
+86-51263068282
Suzhou Jingle Packaging Technology Co., Ltd. mainly develops and produces Aseptic BIB Packaging/Bag Products for food, beverage, and non-food fields, supporting the filling equipment, selling self-produced packaging products, and providing corresponding after-sales services.
Keep in touch
English
中文简体
русский
Español