PE bags are the most widely used form of plastic packaging in the world – from the weekly market to the food industry, from the pharmacy to e-commerce shipping. But two very different materials hide behind the abbreviation “PE”: LDPE and HDPE. Anyone who confuses them quickly buys the wrong bag. This guide explains the differences physically, visually and in use – and tells you exactly when you need which variant, how food-grade certifications work and which sustainable PE bag alternatives are available today.
Table of contents
- What are PE bags?
- LDPE vs. HDPE in direct comparison
- How do I tell LDPE from HDPE?
- When LDPE, when HDPE?
- PE bag variants at a glance
- Thicknesses (microns) for various applications
- Food-grade PE bags
- Printing PE bags
- Recycling, GRS and sustainable alternatives
- Buying PE bags
- Frequently asked questions
What are PE bags?
PE bags are packaging bags made from polyethylene (PE) – the most produced plastic in the world. Polyethylene is created by polymerising ethene molecules and comes in several density classes. The relevant ones for bags are above all LDPE and HDPE. Common synonyms are film bags, poly bags and, in general, plastic bags.
LDPE vs. HDPE in direct comparison
| Property | LDPE (low-density PE) | HDPE (high-density PE) |
|---|---|---|
| Density | 0.910–0.925 g/cm³ | 0.941–0.965 g/cm³ |
| Appearance | soft, slightly milky-transparent | harder, can be transparent or white |
| Feel | soft, stretchable, supple | firmer, rustles noticeably |
| Tear resistance | medium, highly stretchable | higher per wall thickness |
| Puncture resistance | high (through stretchability) | lower (more brittle) |
| Cold resistance | down to −50 °C | down to −40 °C |
| Heat resistance | up to approx. 80 °C | up to approx. 110 °C |
| Printability | very good (flexographic, gravure printing) | good |
| Typical application | shipping bags, films, tubular bags, ziplock | vest carrier bags, bin bags, tight-rustling bags |
| Recycling code | 04 PE-LD | 02 PE-HD |
How do I tell LDPE from HDPE?
- Sound: HDPE rustles noticeably, LDPE is rather quiet and soft.
- Feel: HDPE feels harder and thinner, LDPE is soft and rubbery-stretchable.
- Appearance: LDPE looks slightly milky, HDPE is often clearer or strongly white.
- Recycling code: embossed triangle with “04” = LDPE, “02” = HDPE.
- Reaction to pressure: if you crumple a bag: LDPE stays partly deformed, HDPE springs back immediately.
When LDPE, when HDPE?
LDPE is the right choice for:
- Shipping bags and poly bags for e-commerce
- Food-grade bags with high flexibility (bakery, take-away)
- Printed promotional packaging
- Tubular film for in-house production (see film bag guide)
- Resealable bags (ziplock bags, slider bags)
- Liners for cartons and big bags
HDPE is the right choice for:
- Vest carrier bags with high carrying capacity at minimal wall thickness
- Waste and refuse bags (oil-resistant, cold-resistant)
- Bags with a deliberately “rustling” appearance
- Packaging in which the film must stay thin (cost / material)
PE bag variants at a glance
- Ziplock bags – with zip, usually LDPE, resealable
- Slider bags – with slider, also LDPE
- Flat bags – simple PE bags without closure
- Stand-up pouches – standing, often composite material with PE inner layer
- Side gusset bags – with gusset for more volume
- Adhesion seal bags – with self-adhesive strip, made from PP/OPP (not PE)
- Cross bottom bags – LDPE film with a stable cross bottom
- Side gusset sacks – robust PE sacks for industry
- Tubular film – PE on a roll for in-house production
Thicknesses (microns) for various applications
| Thickness | Field of use |
|---|---|
| 15–30 microns | Knotted bags for loose food |
| 30–50 microns | Light shipping bags, poly bags for clothing |
| 50–80 microns | Standard for most applications |
| 80–120 microns | Heavy contents, industrial bags |
| 120–200 microns | Big bag liners, very heavy contents |
Food-grade PE bags
Both LDPE and HDPE are food-grade in principle – provided they are certified to EU 10/2011. When buying, look for the “glass and fork” symbol or the explicit “food-grade” label. We send declarations of conformity on request. In addition, many of our bags have an LFGB certification.
Recommendations:
Printing PE bags
PE bags can be printed excellently with a logo, branding or notices – typical methods are flexographic printing (cheap, ideal for large quantities), gravure printing (premium quality for branded products) and screen printing (small quantities, thick ink layer). More under print bags or bespoke order.
Recycling, GRS and sustainable alternatives
PE is recyclable as a single material and belongs in the recycling collection. New films and bags are made from the recycled PE – an established cycle. Recycled PE bags with a GRS certificate (Global Recycled Standard) consist of 100% post-consumer material, are functionally identical and considerably reduce the carbon footprint.
Additional options:
- Bio-PE from sugar cane – chemically identical to fossil PE, but from a renewable raw material
- Compostable bags to EN 13432 – for specific applications (organic waste bin)
- Recycled LDPE / recycled HDPE – the pragmatic, most established “green” material → sustainable packaging
Buying PE bags
You order PE bags directly from the manufacturer via the packaging bag hub. Advantages: no dealer margin, original declarations of conformity, individual bespoke orders possible, free samples before bulk orders.
Frequently asked questions
Are PE bags compostable?
Standard PE bags are not compostable, but fully recyclable. There are special bio-based PE variants from sugar cane (bio-PE) which are also recyclable but made from renewable raw materials. For genuine compostability to EN 13432 you need a different material class – contact us for advice.
How do I tell LDPE and HDPE apart in practice?
HDPE rustles noticeably and feels harder. LDPE is soft and stretchable. By recycling code: “04” = LDPE, “02” = HDPE.
Which thickness (microns) do I need?
Rule of thumb: 40–60 microns for light bags, 60–100 microns for standard loads, 100+ microns for heavy contents. For tubular film you choose the thickness according to the machine and contents.
Is PE toxic or does it contain plasticisers?
Pure PE (LDPE/HDPE) contains no plasticisers and is harmless to health. Food-grade PE bags have been standard in the food industry for decades and are regarded as one of the safest packaging materials of all.
How hot can LDPE / HDPE get?
LDPE: up to approx. 80 °C. HDPE: up to approx. 110 °C. For microwave bags or vacuum cooking you need special, much more highly certified materials.
Are PE bags reusable?
Yes, provided they are not damaged. LDPE bags with a ziplock or slider closure in particular last many hundreds of opening cycles.
What is the difference between PE and PP?
PE (polyethylene) is softer, more stretchable and usually slightly milky. PP (polypropylene) is harder, crystal-clear transparent, crackles more and is more heat-resistant. Adhesion seal bags are usually PP/OPP, classic film bags usually LDPE.
What role does GRS certification play?
GRS (Global Recycled Standard) certifies the recyclate content across the entire supply chain. A PE bag with a GRS seal is verifiably made from recycled PE – important for brands with sustainability goals.
How do I store PE bags correctly?
Dry, dark, at room temperature. Avoid direct sunlight (UV makes PE brittle). In their original packaging most PE bags are stable in storage for years.
Can I also get PE bags printed with a logo?
Yes – all our PE bags can be printed individually as part of a bespoke order. The minimum quantity at which this becomes economical depends on the printing method.
Which PE bag variant is suitable for shipping?
For e-commerce shipping, LDPE poly bags or shipping bags with a self-adhesive closure are standard. → Shipping & bags.
Straight to the range: → All PE bags · → PE films · → Sustainable PE bags