Flexibility
High elongation and soft feel vs HDPE; good for compliant features.
LDPE
LDPE Injection Molding: Properties, Applications and Design Guide
Flexible low-density polyethylene for compliant molded parts. Compare siblings, prepare your RFQ, and upload CAD for an instant quote.
LDPE
When LDPE belongs on the BOM
Flexible polyethylene spoke. Processing windows and mold settings stay on the datasheet; this page covers selection and RFQ context.
Low-density polyethylene (LDPE) is a flexible, semi-crystalline polyolefin for injection molded parts that must bend, snap back, or seal without engineering resin cost. Typical uses include squeeze caps, compliant plugs, soft-touch packaging components, and labware where toughness at low temperature matters more than rigid geometry. LDPE is a weak fit when you need high stiffness, tight dimensional stability, sustained heat, or load-bearing structure; HDPE, PP, or PET usually route better. At NetProto, LDPE programs run from first-article validation through production on one hardened steel tool with no minimum order quantity. If you are choosing between flexible PE grades, start with the comparison cards below or upload CAD for DFM feedback on the instant quote platform.
Key traits
Why buyers specify LDPE
Engineering and sourcing highlights. No NetProto shrink or barrel temperature figures here.
Chemical resistance
Strong moisture barrier; many grades resist common acids and bases.
Program fit
First articles through production on one steel tool, no MOQ.
NetProto platform
Upload CAD for instant quoting and DFM feedback before tooling release.
Tooling lead time
Hardened steel tool build in about 10 business days on qualified programs (part complexity dependent).
Common grades
Common LDPE (Low Density Polyethylene) grades by use case
Pick one of these on the instant quote, or name any other commercial grade in the RFQ notes.
| Use case | Example grade | Typical parts |
|---|---|---|
| General purpose | Dow 722 | Flexible containers, soft industrial parts, general moldings |
| Flame retardant | Maxxam FR PE 161-1A | Parts needing UL-rated flame retardant polyolefin performance |
| General molding | Lotrene LDPE MG70 | General low density polyethylene moldings and packaging |
Applications
Where LDPE shows up in molded parts
Typical uses and what to specify on the PO. Confirm grade, additives, and compliance documents on the supplier TDS.
| Application | Why LDPE | Specify on the PO |
|---|---|---|
| Squeeze caps and dispensing closures | Hand pressure deforms and recovers without TPE cost | LDPE grade, color, food or chemical exposure if any |
| Flexible plugs and protective covers | Impact absorption and snap fit in thin sections | Hardness feel target or sample part |
| Labware and fluid handling | Chemical resistance in disposable components | Fluid list, sterilization method if required (supplier grade filter) |
| Consumer packaging inserts | Soft retention features in trays and boxes | Cosmetic class on visible surfaces |
Not ideal for LDPE
Route to a sibling resin instead
When flexibility is not the main requirement, these pages are better starting points.
HDPE
Stiff PE for crates, pails, and structural panels.
HDPEPolypropylene
Living hinges and higher heat than LDPE.
PolypropylenePET
Clarity and bottle preform programs.
PETRFQ
Ready to quote? Have this information ready
Prepare these details for engineering and sourcing. Upload CAD on the instant quote platform when your geometry is ready.
LDPE vs HDPE intent (flexible vs stiff) or a reference sample
Chemical or fluid exposure in service
Food, potable water, or other compliance filters (supplier documentation)
Color: natural, black, or masterbatch with let-down if known
Commercial grade, or the use case to match (flexibility, flame retardant, general packaging and soft parts)
Expected annual volume (helps cavity and tool planning)
Optional: target piece-price band for sourcing discussions
Next step
Upload CAD for an instant quote
Grade not finalized? Note flexible PE on the RFQ and attach environment notes. Engineering can suggest LDPE vs HDPE after DFM review.
Compare and explore
Related polyethylene guides
Pairwise comparisons and sibling pages. LDPE vs HDPE compare page ships separately.
LLDPE
Tougher flexible PE with better stress crack resistance.
Learn moreHDPE
Stiffer PE for caps, containers, and outdoor utility parts.
Learn morePolypropylene
Higher heat and hinge-friendly options when LDPE is too soft.
Learn morePP vs PE
Packaging and container routing across polyolefins.
Learn moreReading a material datasheet
What the TDS (Technical Data Sheet) values mean for a molded part.
Reading a material datasheetSpecify resin grade on an RFQ
How to write grade, color, and fillers so the quote matches the part.
Specify resin grade on an RFQFAQ
LDPE injection molding FAQ
What is the difference between LDPE and HDPE for injection molding?
LDPE is softer and more flexible with higher elongation, while HDPE is stiffer and better at holding shape under load. At NetProto, list your flexibility target or send a sample so DFM can confirm whether LDPE or HDPE matches the part.
Does LDPE require drying before injection molding?
Most LDPE grades are non-hygroscopic and do not need drying like nylon or PET, but always follow the supplier TDS for the exact grade. At NetProto, attach the datasheet to your RFQ when moisture-sensitive additives or masterbatches are involved.
Can LDPE parts be transparent?
LDPE is typically translucent to opaque, not water-clear. At NetProto, if clarity is the primary requirement, route the program toward PET, clarified PP, or PMMA rather than expecting optical transparency from LDPE.
Is LDPE suitable for food-contact molded parts?
Food-contact suitability comes from the specific resin grade and supplier documentation, not from the molder. At NetProto, state the compliance filter on your RFQ and mold the commercial grade you specify or approve from your supplier.
What is the minimum order quantity for LDPE parts at NetProto?
NetProto has no minimum order quantity on molded parts from your production tool. That supports LDPE validation runs before you scale flexible packaging or consumer components. Upload CAD on the instant quote platform to scope tooling and parts.
Can LDPE replace PP for living hinges?
Living hinges need fatigue resistance and hinge geometry tuned to PP copolymers, not LDPE softness. At NetProto, use LDPE for compliant seals and flexible features, and link PP when the drawing calls out hinge tabs or repeated flex cycles.
Next step
Quote LDPE parts with your CAD
Upload geometry and note LDPE or flexible PE on the instant quote platform.