Surlyn® Sealants

A Tough, Clear Sealant Resin Providing Packaging Integrity

With its unique combination of excellent toughness, clarity, and unrivalled seal-through contamination properties, DuPont™ Surlyn® is a premier sealant resin for all sorts of packaging applications.

DuPont™ Surlyn® sealant resin seals through contamination and has excellent hot tack, toughness, and clarity. The versatility and proven performance of Surlyn® support high-quality, cost-efficient packaging across a range of packaging applications.

A Unique Combination of Properties

Surlyn® provides a combination of properties that is unique among polymers. This makes it an ideal sealant resin to keep packaged meats, cheese, cereal, snacks, and other dry foods fresh and appealing, while increasing shelf life. It is also well-suited for packaging healthcare and personal care products and household cleaners. It helps reduce product waste, packaging waste, and costs.

Surlyn® performance properties include:

  • Outstanding sealing through oil, dust, and powder contamination, low seal initiation temperature, and the broadest range of sealing temperatures
  • High hot tack strength and superior performance under a broad range of hot tack temperatures
  • Superior vapor and moisture barriers
  • Toughness through excellent puncture and abrasion resistance
  • Strong, peelable seals perfect for cereal, cracker, and snack bag liners
  • Tight secondary seal helps increase product shelf life
  • Excellent formability
  • Adhesion to meat proteins, which helps increase shelf life and reduce purge and cookout

High Line Speeds, Reduced Leakers

Specially engineered to work with high-speed processing equipment, Surlyn® seals quickly and tightly, even when the seal surface is contaminated with dust or liquids. Surlyn® allows the seal to be stressed, but stay closed, even while the resin is still molten, and over a wide range of sealing temperatures. Surlyn® has a broad sealing range, requiring less machine fine tuning to get strong, peelable seals.

These properties help maintain higher packaging line speeds and reduce the number of seal failures and leakers off-machine, throughout distribution, and in-store.

Fresh and Processed Meats

Surlyn® sealant resin can meet specific needs of different types of meats and even seafood products.

Seafood and meat packagers find vacuum-skin secondary sealing with Surlyn® visually appealing. Good secondary seals and surface adhesion to meats and seafood form a second skin around the product, helping to minimize migration of liquids in the packaging for a clean, appetizing presentation. Ionic bonding within the polymer produces a high-gloss effect and superior film strength, helping create an impression of premium, “heavy-weight” packaging.

Surlyn® can be coextruded with all traditional oxygen barrier materials and structural resins such as PVDC, EVOH and nylon, frequently reducing overall packaging costs. Typical meat package structures using Surlyn® include:

  • Coextruded multilayered film, formed and non-formed – good for marinated and processed meats
  • Laminated composites for thermoforming, overwrap and lidding
  • Shrinkable thermoforming bags – good for cook-in ham
  • Preformed pouches – good for processed or subprimal meat
  • Shrink bags and non-shrink bags – good for fresh meats
  • Single-layer film, formed and non-formed – good for frozen meat cuts

Cereals, Snacks, and Dry Foods

Surlyn® sealant resin can be modified to control its opening force and provide a more consistent peel compared to other resins that may rely on sealing temperature to control peel force. The opening force of Surlyn® can be controlled by varying the thickness of the Surlyn® layer, while continuation peel force can be controlled by mixing different grades. This allows Surlyn® to deliver:

  • Excellent peelability for easy opening
  • Stable peel performance over time with low aging effects
  • Consistent peel strength over a range of sealing temperatures
  • Reduced potential for seals to open during shipping and handling due to its high-performance seal characteristics
  • Excellent tear propagation properties for directional tear, if  desired 

For snacks and dehydrated foods, using Surlyn® in aluminum-based pouches provides fewer taste and flavor issues due to the minimization or elimination of primers. And it provides a strong, consistent seal to aluminum packaging, forming an excellent moisture barrier for a variety of snacks.

Some typical structures include:

  • Moisture-sensitive cereals:
    (HDPE - HDPE - Surlyn® E185SB)
    (HDPE - HDPE - Surlyn® blend); where the blend might be: [1601+1652] or [1650SB+PB-1] or other variants.
  • Moisture-sensitive cereals needing flavor barrier:
    (HDPE - HDPE - tie - EVOH - tie - HDPE - Surlyn®); where the Surlyn® is similar to above examples.
  • Potato chip/pretzel pouches:
    BOPP / print / primer / LDPE / met-OPET / primer / LDPE / Surlyn®
  • Drink powder sachets:
    Overlacquer / print / 52μ Paper / 14μ LDPE / 7μ Alu / 16μ Surlyn®
  • Cake mix pouches:
    12μ BOPP / print / adhesive // 54μ Paper / 20μ LDPE / 14μ Surlyn®

Stand-Up Pouches with Surlyn® Burst Peel

DuPont™ Surlyn® Burst Peel technology provides easy, no-spill openings, and, in some cases, re-closing features. It also increases shelf appeal by helping make pouches stand up straight.

Surlyn® Burst Peel technology can be used in blown-film or cast-film processes. It can be used in laminates with other substrates such as Mylar® OPET films or OPP, or in coextrusion with HDPE, PA, EVOH, or other barrier resins. It can also be applied by extrusion coating onto paper, aluminum, or metallized films.

Soft Cheese

Surlyn® sealant resin provides the highest possible seal integrity for soft cheese (i.e. mozzarella) packaging. Its clarity and formability enhance consumer appeal.

Typical packaging structures include top film and thermoformed bottom or deep-draw VSP bottom formats:

  • Surlyn® is generally used with nylon in the bottom forming web and with polyester in the top web. In both cases, it serves as the inner heat-sealing layer.
  • Forming webs incorporating Surlyn® are highly conformable and help maintain the barrier layer throughout the structure during thermoforming.

Ready-to-Eat Meals

Surlyn® can be combined with other resins to create extremely transparent multilayer films with oxygen barrier properties to prevent the discoloration of ready-to-heat foods in thermoformable containers. It also helps prevent the build-up of purge around the edges of pre-cooked entrées for more appetizing appearance.

Health and Personal Care Items

Health and personal care packaging for products such as alcohol swabs, tablets, cosmetics, prophylactics, and towelettes also benefit from Surlyn® sealant resin.

Surlyn® provides excellent film clarity, formability, and tamper resistance. It offers high gas transmission for ethylene oxide, low-temperature heat seals, and excellent hot tack. It adheres to foil without primer and is resistant to foil-flex cracking and pinholing. Its clean peel provides easy product access.

Typical applications include flexible lidding, thermoformed pouches, form-fill-seal pouches, vacuum skin packages.

Typical structures may include:

  • Paper / LDPE / foil / Surlyn®
  • OPP / primer / LDPE / foil / Surlyn®
  • Foil / Surlyn®
  • (EVA - Surlyn® - EVA)
  • (Nylon - tie - PE - tie - EVOH - tie - PE - Surlyn®)
  • (LLDPE - LDPE - Surlyn®)
  • OPET / ink / primer / LDPE / foil / Surlyn®

Household Cleaners

Surlyn® sealant resin can be used to package household cleaners in flexible pouches. Surlyn® meets tough performance requirements with the best hot tack, seal-through contamination, and stiffness of any high-performance sealant. Surlyn® used in these rugged, leak-proof, flexible packages can help reduce storage and shipping costs.

Variety of Grades, Customization Available

Surlyn® sealant resin is available in a variety of grades, each with a different balance of properties. Working with DuPont development support experts, brand owners and converters can tailor the sealability, puncture resistance, toughness, or flexibility properties of structures by selecting the right grade of Surlyn®.

Sustainability Benefits and Downgauging

The direct adhesion of Surlyn® to aluminum, as well as its superior barrier performance with relation to oil, results in a greater resistance to delamination without the use of solvent-based primers or glues. Surlyn® helps reduce waste and materials usage with fewer seal failures in processing and fewer leakers on shelf.

Surlyn® sealant resin can also offer substantial downgauging potential– up to 30%, due to its toughness, which reduces puncture rates during handling and transportation, and its stiffness, which reduces overall thickness while still allowing for good machinability.