PE Coated MG Paper for Food Packaging: How to Choose Base GSM and PE Coating Weight by Application

PE Coated MG Paper for Food Packaging

How to choose base GSM and PE coating weight by application

Choosing PE coated MG paper for food packaging starts with two separate decisions: how much paper the pack needs for handling and converting, and what PE layer the food-contact surface needs for barrier and sealing. A burger wrap, a dry-food sachet and a frozen-food liner can require different structures even when their total grammage is similar.

This guide helps packaging buyers and converters shortlist base GSM and PE coating weight for flexible wraps, liners, bags and selected sachets. The final specification should follow the food, pack design, contact time and production conditions. For formed paper cups, use our separate cupstock paper specification guide.

Quick Answer

Select base GSM for the required flexibility, strength and machine handling. Select PE coating weight for the required barrier, coating coverage and seal performance. Specify both separately, then qualify the finished pack.

For an initial supplier discussion, lightweight wraps can be evaluated around 30–35 g/m² base paper plus 10–12 g/m² PE; snack bags around 40–50 g/m² plus 12–15 g/m² PE; and more demanding frozen-food wraps around 60–70 g/m² plus 18–25 g/m² PE. These are illustrative trial bands, not industry standards, guaranteed performance levels or a statement of available grades. Use the application matrix below to identify the checks that matter for each format.

Ask for three things before ordering: a layer-by-layer specification, test results relevant to your use conditions, and representative material for a converting and food-contact trial.

What Base GSM and PE Coating Weight Each Control

MG means machine glazed. During papermaking, contact with a polished drying cylinder gives one side of the paper a smoother surface. Depending on the grade and construction, that surface can support printing or further converting. MG describes a surface finish; it does not by itself guarantee grease resistance, wet strength or suitability for a specific food.

Base GSM is the mass of the paper before PE coating, expressed in grams per square metre. It influences handling and pack body, but strength also depends on the fibre furnish, bonding, moisture and paper direction. Two papers with the same GSM can perform differently.

PE coating weight is the mass of polyethylene applied per unit area. It contributes to resistance to grease, liquid water and water vapour, and can provide a heat-sealable surface. PE is not an absolute barrier: resin grade, layer continuity, folds, edges and seals all affect the result.

For a simple structure, total GSM = base GSM + PE GSM on each coated side. A 40 g/m² base with 15 g/m² PE is nominally 55 g/m² before any other layers. Always ask whether a quoted “55 GSM” refers to the base or the finished material.

Application Matrix for Base GSM and PE Coating Weight

Use these bands to request trial samples and compare options. They are illustrative starting points for the stated uses, not validated recipes. PE values are for one coated side; confirm the resin grade, surface orientation, tolerances and supplier availability. More demanding uses may need a different construction altogether.

Read the matrix by exposure, not only by product name. A sandwich eaten shortly after purchase presents a different requirement from a chilled retail sandwich held for several days. A frozen liner inside a protective outer pack also differs from a standalone sealed pack.

The flour-bag example does not cover industrial multiwall sacks. The frozen-wrap example does not establish suitability for vacuum packaging, exposed bones or seafood shells. A higher PE GSM alone does not qualify a pack for hot filling, retort processing, microwaving or oven heating.

For substrate sourcing, see MG base paper for food wrapping and confirm the coating construction separately.

How to Select Base GSM for the Finished Pack

Start with the finished dimensions, fill weight and handling method. Hand wraps need enough flexibility to conform around the food. Bags need sufficient strength around seams, folds and carrying points. Machine-fed material must also run at the intended tension without excessive stretching, tearing or curl.

For the same base grade, increasing grammage generally adds paper mass and can improve handling strength. It does not provide a universal puncture rating, minimum line speed or guaranteed standing stability. Compare tensile and tear properties, thickness, moisture and relevant wet-strength data alongside GSM, using consistent test methods and conditioning.

When reducing base GSM, trial folding and wrapping with the real food. Check whether the pack holds its shape, tears at corners or becomes difficult to separate and feed. Approve the lowest grammage that consistently meets the pack specification with an agreed operating margin.

How to Select PE Coating Weight and Resin Grade

Begin with the failure you need to prevent: grease marks during service, liquid seepage, moisture gain in a dry product, or weak heat seals. These are different acceptance criteria. A layer that controls visible grease staining may still allow enough water vapour through to affect a moisture-sensitive product over storage.

Within a comparable construction, increasing PE weight can improve coverage and reduce water-vapour transmission. The benefit depends on the resin and the continuity of the coating. An average coat weight can hide local thin areas, and defects at folds or seals can dominate finished-pack performance. Specify acceptable variation and inspection methods with the supplier.

LDPE is commonly used in extrusion coating. HDPE or blends may offer a different balance of moisture barrier, stiffness and sealing behaviour. Resin families contain many grades: choosing HDPE does not automatically produce stronger seals, and choosing LDPE does not establish a universal low-temperature limit. Ask for data on the proposed grade and finished construction.

To isolate the effect of coating weight, compare two supplier-supported PE weights on the same base grade and resin system. For example, a 40 + 12 structure and a 40 + 15 structure have nominal totals of 52 and 55 g/m². Run both under equivalent conditions and judge them against the same barrier, seal and handling requirements.

Barrier Testing and Shelf Life

Water vapour transmission rate, usually abbreviated WVTR and sometimes called MVTR, describes the mass of water vapour passing through a defined area over time under specified conditions. Results are commonly reported in g/m² per day. A lower value indicates less transmission only when the methods and test conditions are comparable.

Request the method and edition, test temperature, relative humidity on each side, sample orientation, conditioning and units. ISO 2528 and ASTM E96/E96M describe gravimetric approaches; the laboratory should confirm a method suitable for the material and expected transmission range. Naming a standard alone does not define the test conditions.

There is no PE GSM that automatically delivers 12, 18 or 24 months of shelf life. The required barrier depends on pack area, product sensitivity, initial condition, storage humidity and temperature, and the integrity of the finished pack. Oxygen, aroma or light protection may also matter, particularly for products such as coffee, spices or fatty powders. Where extra barrier functions are needed, paper/PE/aluminium foil laminates are one construction category to discuss, subject to product and process qualification.

Use sheet tests to compare materials, then test filled packs through the intended storage and distribution cycle. Include seams, folds and cut edges. For short-service wraps, evaluate grease staining, leakage and condensation over the actual holding time. For frozen applications, assess the agreed freezing, handling and thawing cycle rather than assuming a resin temperature rating qualifies the whole pack.

Printing and Converting Checks That Affect Your Choice

Identify the coating side and printing side

Specify the MG side, PE side, food-contact face and outward print face on an approved drawing or sample. Coating on the less smooth side is one possible construction, not a universal rule. If both sides are coated, specify each layer separately and confirm why the second layer is needed.

The print process should match the actual surface. When printing directly onto PE, agree on surface treatment, the ink system and a treatment measurement method. The required dyne level depends on that combination; 40 dynes/cm is not a universal acceptance limit. Surface treatment can decay during storage, so check the material at printing and verify adhesion. A fixed 72-hour expiry rule is not appropriate for every grade and storage condition.

Match the seal geometry to the coated surfaces

A fin seal normally brings two inner faces together, which can allow PE-to-PE sealing on a one-side-coated material. A lap seal brings an inner face against an outer face. If that outer face is uncoated paper, the interface needs a specifically qualified sealing or adhesive solution. One-side PE coating therefore does not make every fin or lap seal equivalent.

Establish the operating window using jaw temperature, pressure, dwell time, seal geometry and line speed together. The resin melting range is not the same as the machine setpoint or the actual temperature at the seal interface. Check seal strength after cooling, leak resistance and, where needed, hot tack—the ability of a newly made seal to withstand load before it cools. Include realistic food or powder contamination at the seal area.

Specify rolls for the actual machine

Agree on slit width and tolerance, maximum roll outside diameter and mass, core inside diameter, winding direction, coating orientation, splice limits and edge quality. Add requirements for curl, coefficient of friction and unwind behaviour where they affect feeding. Use the converter’s limits rather than treating ±2 mm width tolerance or any standard core size as suitable for every line. See the complete PE coated MG paper specification checklist for the broader purchasing framework.

Buyer Checklist for a PE Coated MG Paper RFQ

An effective request for quotation lets suppliers propose a structure against measurable needs. Include the following information and identify any fields that still require a trial.

Confirm food-contact suitability for the complete construction

“Food-grade PE” alone is insufficient. Request evidence for the base paper, polymer, additives, inks and adhesives as applicable to the final pack and intended food contact. For EU supply, assess the food-contact framework and applicable material-specific and national rules, including the requirements applicable to plastic layers. For US supply, request the regulatory basis for the components and their intended use. Match documentation and any migration testing to the actual food, contact duration and temperature.

Compare cost at the same pack size and usable output

Compare cost per usable square metre or per thousand finished packs, including converting waste and rejected packs. A price per tonne alone can obscure differences in total GSM and yield.

For example, reducing total grammage by 5 g/m² saves a calculated 312.5 kg per million 250 × 250 mm sheets, before process losses. This is a mass calculation, not proof of lower emissions or a lower packaging fee. Those conclusions need their own evidence. PE coated paper contains plastic; recyclability depends on the full construction and the collection and reprocessing system in the destination market.

How to Approve a New Structure

Use the current approved material as a control where possible. Agree on pass criteria before running trials so that a lighter sample is judged against the same requirements as the existing pack.

Check the incoming material. Confirm layer weights, dimensions, coating orientation and uniformity, roll condition and traceability.

Run the intended converting process. Assess print quality, feeding, folding, sealing and waste after the line reaches stable operation. Include normal production variation.

Test filled packs. Evaluate the relevant hold time or storage cycle, leakage, grease staining, handling and shelf-life indicators. Include distribution stresses where applicable.

Approve a controlled specification. Retain samples and record the agreed tolerances, test methods and operating window. Reassess material, resin or process changes that could affect performance.

Frequently Asked Questions

What is the difference between base GSM and total GSM

Base GSM measures the paper before coating. Total GSM includes the paper and all coating or other layers. For a simple one-side-coated material, 35 g/m² paper plus 12 g/m² PE gives a nominal total of 47 g/m². Confirm what a supplier’s quoted GSM includes.

What GSM should I choose for a burger or sandwich wrap

A 30–35 g/m² base with 10–12 g/m² PE is an illustrative starting point for short-service wrapping trials. Final selection depends on food temperature, grease, moisture, pack size and holding time. A retail pack with a longer shelf life needs a different assessment.

Does a heavier PE coating always give a better pack

No. It may improve coverage or barrier within a comparable structure, but it also changes material use and can affect handling. Defective coating, unsuitable seal geometry or poorly controlled sealing will not necessarily be corrected by adding PE. Compare finished packs against defined requirements.

Can PE coated MG paper be used for sauce sachets

Possibly, with a qualified construction and pack design. Base GSM and PE weight alone cannot establish liquid containment, product compatibility, processing suitability or shelf life. Specify the sauce, filling conditions and storage period, then assess whether additional functional layers are needed.

Is PE coated MG paper suitable for frozen food

Some constructions can be suitable as wraps or liners. Test the finished structure for low-temperature handling, folds, adhesion, puncture, moisture exposure and thawing under the intended conditions. Sharp bones or shells and vacuum-packed products may require a different protective design.

Can one-side PE coated MG paper be heat sealed

It can support PE-to-PE seals where the pack geometry brings coated faces together. A lap seal may bring PE against uncoated paper instead, so the design needs a qualified seal or adhesive solution. Confirm the contact faces and test the closure on the intended machine.

What should I send when requesting samples

Send the application, food and fill weight, pack dimensions, contact and storage conditions, proposed base and PE weights, print and seal layout, and machine details. Include your current material or failure examples and the test criteria the new grade must meet.

Request Samples for Your Application

Send Sure Paper your pack format, food-contact conditions and current base GSM and PE coating weight, if known. Include the problem you want to solve—such as grease staining, weak seals, tearing or excessive material use—and your converting requirements.

Request a PE coated MG paper quotation and trial samples. Ask for the proposed layer structure, available grades, applicable food-contact documentation and the trial quantities needed to evaluate the material on your line.

Evidence for the Technical Review

These sources support material behaviour and validation, not Sure Paper product certification or standard application recipes.

MG base grades and uses. Billerud flexible packaging kraft papers and Stora Enso Endura MG describe grades for wrapping, bags and coating or lamination. Select a specific grade for the application.

Coating and sealing. LyondellBasell extrusion coating guide covers resin properties and coating defects. ASTM F2029 explains the role and limitations of laboratory heat-seal evaluation; seal strength and leak tightness require different checks.

Water vapour testing. ISO 2528 and ASTM E96/E96M support stating the method and test conditions rather than comparing bare WVTR numbers.

Surface treatment. Enercon surface treating handbook explains treatment and decay. Enercon adhesion guidance explains why dyne level alone is insufficient to assure adhesion.

Food contact. European Commission legislation overview and FDA component regulatory-status guidance support component and intended-use checks. The article is not a product compliance declaration.

Search guidance. Google Search Central: people-first content, title links, crawlable links, Article structured data and documentation updates. The update log records the end of FAQ rich results from 7 May 2026.