TL;DRChoose a PE valve bag when you fill powders or granules on a spout packer and want less dust and tidy pallets. Choose an open-top heavy duty PE square bottom bag when you fill by hand or use a bag-neck sealer, or need very large sizes. Chuangda makes both: valve bags carry 20–50 kg with up to 8-color printing, and block bottom bags run from 300×300×500 mm to 1200×1200×2000 mm.
01Valve or Open-Top: The Question Behind Every Heavy-Duty PE Bag Order
Buyers of chemical powders, fertilizer, resin and feed usually ask one thing first: valve or open-top? Once filled, both bags stand as a square block. The real difference is how product goes in, how the bag closes, and what that does to line speed, dust and warehouse space.
Below we compare the two PE bag types from our own product pages, so every figure can be checked against the specification.
02How Each Bag Works
Open-Top Heavy Duty PE Block Bottom Bag
Made from HDPE or LLDPE with a heat-sealed square bottom, this bag stands upright without support. You can fill it by hand, close it with a bag-neck sealer, then heat seal or stitch the mouth.
Heavy duty PE square bottom bag
PE Valve Bag
A PE valve bag is filled through a pre-formed valve sleeve on a spout packer, then the valve closes or is sealed. It is made from 100% new PE for loads from 20 kg up to 50 kg.
03PE Valve Bag vs Block Bottom Bag: Side-by-Side Specs
| Feature | Open-Top PE Block Bottom Bag | PE Valve Bag |
|---|---|---|
| Filling method | Manual, bag-neck sealer, or heat-sealed valve spout | Spout packer, manual or automatic |
| Closing | Heat seal or stitch | Valve closes or is sealed after filling |
| Load range | 20–25 kg up to custom loads above 50 kg | 20–50 kg |
| Size range | 300×300×500 to 1200×1200×2000 mm | Body 440–920 × 350–610 mm |
| Stacking | At least 5 tiers | Cube shape for palletizing, embossed body to prevent slipping |
| Printing | Flexographic, up to 8 colors | 8 colors on body, 2 colors on bottom |
| Typical products | Grain, feed, building materials, chemical granules | Fertilizer, resin, cement, salt, sugar, minerals |
Paper valve sacks are the third option many buyers weigh. Based on our product guidance, PE tends to win when humidity and puncture risk dominate. Paper has the edge when de-aeration speed and paper-stream recovery matter most.
Why Heat Sealing Matters
Our heat sealed PE valve bag melts and bonds the film edges instead of relying on thread.
The product page lists weld strength at 30N/15mm, against 15–20N/15mm for ordinary sewn bags. That means fewer needle holes and less leakage risk for fine powders.
04Find Your Bag by Situation
Manual sealing takes about 15 seconds per bag. Add a bag-neck sealer and the product page cites 15–20 bags per minute.
Pick an internal or external valve and size it to your packer spout. See the FAQ below for the clearance rule.
Valve bags help keep the workplace dust free and resist humidity, which suits fertilizer, resin and cement.
UV stabilizers are an available option. For 40 μm UV-inhibited HDPE builds, the product page limits outdoor storage to 6 months.
Ask for FDA/EC 1935-compliant additives on the block bottom bag, or see our food grade PE square valve bag.
05Block Bottom Size Tiers
For chemical granules and powder raw materials.
For grain, animal feed and building materials.
For fertilizers and bulk industrial commodities.
065 Steps to Choose the Right PE Bag
07The Factory Behind the Bags
10,000 m² in Handan, Hebei
More than 100 employees run multiple three-layer film blowing machines, professional printing machines, embossing-edge inserting machines and computer high-speed bag making.
A full-time independent inspection department checks quality from raw material to finished product. About us
Certified Management Systems
08PE Valve Bag FAQ
Slide your mouse over a question to open it. Move away and it folds back.
A PE valve bag is filled through a valve sleeve on a spout packer and keeps dust down. An open-top block bottom bag is filled through its open mouth, by hand or with a bag-neck sealer, then heat sealed or stitched.
Measure the spout outer diameter and add a practical clearance, often 3–6 mm. Then validate with a 10-bag pilot run at your production speed before ordering in volume.
Our heat sealed PE square valve bag page lists weld strength of 30N/15mm, while ordinary sewn bags reach only 15–20N/15mm.
Valve bags carry 20–50 kg. Body length ranges from 440 to 920 mm, body width from 350 to 610 mm, and bottom width from 90 to 180 mm. Colors include white, black and orange.
Stock samples take 2 days and are free. Custom-logo samples take 10–12 days. The valve bag specification lists 25 days for a 20′GP. Confirm final timing and MOQ when you request a quote, because bag size affects both.
Our block bottom bag is made of pure PE and is described as 100% recyclable. Acceptance depends on local film-only collection streams, so check your local rules and keep laminations simple.
Not Sure Which Bag Fits? Send Us Your Filling Line Details
Tell us the product, load and filling method. Our team replies within 24 hours with a recommended bag type, size and sample plan.
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