# LDPE

Select low-density polyethylene by resin grade, additives and manufacturing route; preserve film gauge, orientation and test conditions.

Reviewed: 2026-11-01

Tags: materials, polymers, polyethylene, thermoplastics, film

## Identify the polymer and grade

Westlake's **EF412 blown film** gives typical **24.1 MPa MD** and **18.6 MPa TD tensile strength at break**, by **ASTM D882**. The setup uses **1.25 mil film, 2.5:1 blow-up ratio and 35 mil die gap**, with tests at **23°C / 50% RH** unless stated otherwise. Preserve the direction and film setup. [Westlake EF412 test table](https://www.westlake.com/sites/default/files/EF412%20TDS%2007-07-22_0.pdf)

**LDPE — low-density polyethylene —** is a thermoplastic polyethylene family. LYB distinguishes it from **LLDPE** and HDPE, relating properties to branching and crystallinity. [LYB Guide to Polyolefin Film Extrusion](https://www.lyondellbasell.com/globalassets/lyb/our-solutions/products/documents/polymers-technical-literature/A_Guide_to_Polyolefin_Film_Extrusion.pdf)

For example, **Lupolen 2420D** is described by LYB as non-additivated LDPE pellets with high melt strength for bubble stability during blown-film extrusion. The manufacturer explicitly excludes medical and pharmaceutical applications for this product. That description must not be transferred to every LDPE grade or overridden by a generic polyethylene application list. [LYB Lupolen 2420D](https://www.lyondellbasell.com/en/polymers/p/Lupolen-2420D/bd51db21-61a1-4d8f-b90a-27d75238169f)

## Melt index, density and additives

**Melt index needs its temperature and load.** LYB notes that equal melt indices do not guarantee equal flow behavior; molecular-weight distribution also matters. [LYB extrusion guide, page 5](https://www.lyondellbasell.com/globalassets/lyb/our-solutions/products/documents/polymers-technical-literature/A_Guide_to_Polyolefin_Film_Extrusion.pdf)

Westlake **EF412** has typical melt index **2.0 g/10 min at 190°C / 2.16 kg, ASTM D1238**, and base-formulation density **0.923 g/cm³, ASTM D1505**. Versions include slip/antiblock-containing products and **barefoot EF412AA**; confirm the exact suffix. [Westlake EF412 TDS](https://www.westlake.com/sites/default/files/EF412%20TDS%2007-07-22_0.pdf)

For procurement, document the needed friction/blocking behavior, optical quality, sealing requirements and any surface treatment. Do not choose a substitution from melt index and density alone. Compare the actual application tests and trial the intended equipment, formulation and downstream operations.

## Read film data as film data

The EF412 sheet reports these **typical blown-film** results:

| Property | Machine direction (MD) | Transverse direction (TD) | Method |
| --- | --- | --- | --- |
| Tensile strength at break | 24.1 MPa | 18.6 MPa | ASTM D882 |
| Elongation at break | 440% | 830% | ASTM D882 |

The film setup is **1.25 mil gauge, 2.5:1 blow-up ratio and 35 mil die gap**, with tests at **23°C / 50% RH** unless stated otherwise. These limited-test results are not shipment guarantees. [EF412 test notes](https://www.westlake.com/sites/default/files/EF412%20TDS%2007-07-22_0.pdf)

NOVA's **NOVAPOL LF-0219-A** sheet uses a different reference: **38 µm film**, a **1.5 in extruder, 3 in die, 35 mil die gap and 2.5:1 blow-up ratio**. It lists ASTM D882 tensile strengths of **22 MPa MD / 18 MPa TD**, while explicitly calling the results average laboratory guides rather than specifications. Preserve those conditions rather than ranking the two resins by one isolated number. [NOVA LF-0219-A sheet](https://www.novachem.com/wp-content/uploads/NOVAPOLLF-0219-A_DS_EN.pdf)

## A bounded mass estimate

**Illustrative calculation:** assume a uniform monolayer EF412-base film at **50 µm**, with density **923 kg/m³**, no fillers and no trim loss. Areal mass is:

923 kg/m³ × 50 × 10⁻⁶ m = **0.04615 kg/m² = 46.15 g/m²**.

A 1,000 m² area would therefore contain **46.15 kg** of polymer under those assumptions. This is a geometry/density estimate, not a supplier yield guarantee. Actual gauge distribution, formulation, multilayer construction, start-up waste and trim affect purchased mass per accepted output. The assumed 50 µm gauge differs from the EF412 property-test gauge above.

## Processing and storage

Westlake recommends **360–400°F (approximately 182–204°C) melt temperatures** for EF412 with blow-up ratios **≥1.5:1**, within this product's film-processing scope. [EF412 processing guidance](https://www.westlake.com/sites/default/files/EF412%20TDS%2007-07-22_0.pdf)

LYB's separate **Injection Molding Start-Up for LDPE** technical tip discusses Petrothene injection resins and explicitly describes its values as adjustable start-up conditions rather than absolute limits. It notes that barrel-temperature profiles and other settings depend on machine and part. Do not use a blown-film recommendation as a molding recipe. [LYB injection-molding technical tip](https://www.lyondellbasell.com/globalassets/lyb/our-solutions/products/documents/polymers-technical-literature/tech-topic-injection-molding-start-up-for-ldpe.pdf)

LYB describes polyolefin resin as non-hygroscopic, normally requiring no predrying for extrusion, while emphasizing clean handling. Follow product-specific instructions for actual stock. [LYB film guide, page 9](https://www.lyondellbasell.com/globalassets/lyb/our-solutions/products/documents/polymers-technical-literature/A_Guide_to_Polyolefin_Film_Extrusion.pdf)

NOVA instructs storage of LF-0219-A in a clean, dry place at ambient temperature, warns that prolonged/improper storage can deteriorate properties, and emphasizes contamination prevention. Preserve product and batch identity through storage, blending and regrinding. [NOVA storage guidance](https://www.novachem.com/wp-content/uploads/NOVAPOLLF-0219-A_DS_EN.pdf)

## Service and surface limits

LYB lists **96°C Vicat softening** and **110°C peak melting point** for Lupolen 2420D. Neither is a continuous-use temperature or a hot-fill rating for a finished article. Define sustained loads, creep, dimensional stability, seal performance and exposure duration under actual service conditions. [Lupolen 2420D typical properties](https://www.lyondellbasell.com/en/polymers/p/Lupolen-2420D/bd51db21-61a1-4d8f-b90a-27d75238169f)

LYB identifies environmental stress cracking under stress in contact with liquids such as detergents, oils or solvents. Qualify actual chemical concentration, temperature and loading. [LYB film guide, page 5](https://www.lyondellbasell.com/globalassets/lyb/our-solutions/products/documents/polymers-technical-literature/A_Guide_to_Polyolefin_Film_Extrusion.pdf)

LYB discusses corona treatment for printing polyolefin film. Specify surface preparation and qualify the intended ink/adhesive, seal quality and performance after storage. [LYB surface-treatment discussion, page 25](https://www.lyondellbasell.com/globalassets/lyb/our-solutions/products/documents/polymers-technical-literature/A_Guide_to_Polyolefin_Film_Extrusion.pdf)

## Qualification and source versions

Obtain current product stewardship and regional handling information for the exact resin and additives. A food-packaging application listing does not establish every contact condition, and a resin statement does not certify the converted package. Define any required chemical, migration, barrier, weathering or electrical tests for the intended article.

Primary sources were reviewed November 1, 2026. The Westlake PDF prints **July 7, 2022** and the NOVA PDF **April 20, 2018**. The LYB film guide prints code **6047/1004** and the molding tip **9770/0715**, without an explicit full revision date; those codes are preserved without inferring one. The Lupolen product page has no visible technical revision date.

Release against grade/additives, process, gauge/dimensions, appearance and required functional tests. Distinguish supplier typical data, agreed specifications, lot results and demonstrated finished-product performance.

[Material selection through production](../grades-tempers-and-conditions.md)