Dry food products, such as coffee lightener or powdered drink mix, place minimal demands on the peelable heat seal coating, Dry food constructions include
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Paper / XLDPE / HS – HIPS
Paper / adhesive / OPP / HS – PVC
X = EXTRUDED
For this end use, a water based EVA dispersion would function quite well. There is no toluene to absorb into the LDPE, and the EVA provides an easily peelable bond to the cup stock. An EVA provides an easily peeable bond to the cup stock. An EVA coating can be applied by any method and requires a relatively low drying temperature that will not distort the polyolefin film. FDA compliance on paper and / or polyolefin is also assured with this type of coating.
There are several types of dairy creamer lid stock. The simplest is
Paper / XLDPE / HS – HIPS
For this application, a moisture – resistant, peelable seal is required. An EVA – based gel lacquer is one of the most widely used heat seals. Gel lacquers are a solvent solution of a hot melt. The most common method of application is by directly heated gravure. Here again, a coating with direct food contact compliance on polyolefin film is required. A more sophisticated creamer lid structure is
Paper / XLDPE / AF / HS – HIPS or
Paper / XLDPE / AF / primer / HS – HIPS
An EVA based gel lacquer works well for such applications, but it sometimes bridges or membranes when it is peeled. One such case, a vinyl primer and heat seal must comply with FDA regulation 21CFR175.300.
Jellies, jams. Pancake syrup, fast food sauces are often filled at 170-200 f. Sauces are often acidic and contain aggressive components such as mustard oil. The heat seals used to hold these products must have good hot tack at 200 F to prevent leaking lids, good moisture resistance, moderate grease resistance, and good chemical resistance. One type of construction is
PEST / adhesive / AF / primer / HS – HIPSPVC
Here the heat seal can be a vinyl or vinyl – acrylic applied over a vinyl primer. The primer is important to protect the foil from corrosion by the product. Another approach is
AF / adhesive / PEST / HS – HIPS or PVDC / HIPS PVC PP HDPE
A reinforced EVA gel lacquer will provide good adhesion to the PEST lid substrate as well as good salability to a broad range of cup stocks and good heat resistance for hot fill. Compliance with FDA regulation 21CFR177. is an important factor in these applications. Lidding for fresh and frozen citrus juices is a large and important market. The most common construction is
Print / AF primer / HS – PVC
Where the primer and heat seal are both solvent based vinyls. A pinhole free coating is important to protect the foil from the corrosive citrus juices. Low temperature adhesion is a must for frozen products. Both must comply with FDA regulation 21CFR175.300
Lidding on a clear substrate for greasy foods such as cheese or peanut butter is a challenge. An often used construction is
OPP / print / PEOT / HE – PETC PVC
This heat seal coating is a solvent based EVA / nitrocellulose hybrid with excellent film clarity and grease resistance. It complies with FDA regulation 21CFR177.
Ovenable trays are either PET or SBS board / PET in which food production are either microwaved or heated in a thermal oven up to 400 F. The cover can be
PEST / HS – PET or
SBS / PET / HS – PET
Where SBS = solid bleached sulfite
The heat seal for the film lid mist be clear, have heat resistance to 400 F, and still be peelable after heating. A board lid heat seal need not be clear, but it must have all the other attributes. Polyester – based coatings that comply with FDA regulation 21CFR177. are used in these applications.
Lidding for autoclavable and aseptic applications presents some unique problems. The heat – seal coating must have good adhesion to foil, and they must be sealable to poly propylene for steam sterilization. The coating must also be stable to radiation sterilization. The construction is
AF / HS –PP
And the heat seal is a specially reinforced EVA gel lacquer, which provides a controlled peel. This type of package is used for medical applications, such as sterile – water and hydrogen – peroxide – sterilized aseptic packaging. The FDA regulation for the latter is 21CFR178.
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Few packaging concepts can match restorable lidding for extreme performance requirements. A retortable lid must withstand 121 C, 15 psi steam for 80 min without losing seal integrity and yet remain peeable after long term shelf storage. The special heat seal coating that can function in this environment is a modified polypropylene dispersion known as Morprime. A typical lidding construction could be
0.5 mil PEST / 1 mil AF / Morprime – PP or 2 mil AF / Morprime – PP
This coating is also unique in its selectivity. It must be applied to a metal substrate, such as aluminum foil, and requires drying / curing temperatures of 400 F for 30 – 35 seconds. It is sealable to either cast or molded polypropylene or to another Morprime surface at 450 F for 1 second. Typical food products packaged in retortable cups including apple sauce, orange juice, yogurt and cheese food spreads. Moprime complies with FDA regulation 21CFR175.300
Heat – seal coating for lidding of disposable packages for medical devices are applied onto Tyvek or surgical kraft paper, which is then sealed to several different plastic tray materials. Typical constructions are
Tyvek / primer / HS – PET HIPS HDPE PP
The heat seal coating must have adequate porosity to allow efficient entry and removal or ethylene oxide gas during sterilization, as well as good humidity resistance and sufficient heat resistance to overcome “sterilizer creep” When peeled from the tray, the coating should transfer completely from the lid to the tray flange to show evidence of closure. Specially formulated EVA dispersions have been successful in this application. The large particle size of the dispersion provides good porosity, and the EVA polymer provides a good peelable bond to almost all of the commercially used tray stocks. These EVA coatings are also stable under radiation sterilization. FDA compliance for direct food contact on any substrate makes these waterborne coatings suitable for lidding or medical package. Although this survey of heat seal coatings for lidding has covered a variety of materials, applications, and usage parameters, it is by no means exhaustive. As new lidding substrates and containers materials become available, new heat seal coatings will be required to meet the needs of the converters and end-users
When it comes to food packaging, getting the seal right is just as important as the tray it covers. Lidding film plays a vital role in keeping contents fresh, extending shelf life, and ensuring a secure seal – whether that’s for ready meals, deli produce, or fresh ingredients. At SystemPAK, we offer a versatile range of lidding films to suit various tray materials and sealing requirements. Here, we break down the differences between weld seal and peelable seal options to help you choose the right solution for your packaging needs.
Lidding film is the top layer of a packaging system, designed to seal onto trays made from materials like APET, CPET, or pressed board. The film needs to create a secure seal during the packaging process, which is why factors such as sealing temperature, dwell time, and tray type all matter.
Let’s explore the lidding film options available at SystemPAK – and what makes each one suitable for different packaging applications.
Weld seal films are designed to form a strong, permanent bond with the tray. They’re ideal when tamper-proof packaging or high-pressure sealing is required, offering durability and peace of mind for food producers.
1. ECOPET 12/15mu Weld Seal with Anti-Fog (PCJ)
This high-performance film seals securely to APET, CPET, and rPET trays at temperatures between 140–160°C with a dwell time of 1–3 seconds. For pressed board trays, higher temperatures of 180–200°C and dwell times of 2–5 seconds are recommended due to the increased sealing pressure.
2. PET/PP 12/30mu Weld Seal with Anti-Fog (PCJ)
Designed for all P-type trays, this PET/PP blend delivers reliable sealing at 110–145°C with a 1–3 second dwell time. It also includes anti-fog properties to maintain product visibility on shelf.
Peelable Seal Lidding Films
Peelable films are ideal when a user-friendly experience is essential. These seals hold securely during storage and transit but peel back cleanly when it’s time to open the pack – with no mess or tearing.
3. PET/PP 12/30mu Peelable Seal with Anti-Fog (PCJ)
This film gives you the best of both worlds – a strong seal and easy peel. It performs across a range of P-type trays at 95–145°C, with a dwell time of 1–3 seconds.
Universal Lidding Films
For packers working with a variety of materials, a universal film offers the flexibility to seal to multiple tray types – making it ideal for mixed production lines or evolving product ranges.
4. Universal 101 AF PET23 35mu – Clear with PCR (30%)
This film is designed to seal to most monolayer tray materials. It acts as a peelable seal at shorter dwell times but forms a stronger weld seal as dwell time increases.
5. Universal 101 AF PET50 – 50/12mu Pre-Cut Lids with Pinseal Pattern
This pre-cut option is ideal for specific diameters and tray types, using a clear pinseal pattern for improved grip and seal consistency.
Important Considerations
At SystemPAK, we understand that every production line is different. Sealing temperatures and dwell times can vary depending on:
That’s why we always recommend carrying out your own in-house trials before full-scale production. Our technical team is on hand to offer advice and product samples to support your testing process.
Need Help Choosing the Right Film?
Whether you’re looking for a high-performance weld seal for tamper-proof packaging or a peelable option for consumer convenience, we’ve got a solution that fits. Our films are tested for quality, consistency, and shelf-life performance – helping you deliver the best possible product to market.
Are you interested in learning more about flat pouch packaging? Contact us today to secure an expert consultation!