Lock-seal BOPET/CPP Lidding Films

What Is BOPET/CPP Lock-Seal Lidding Film?

BOPET/CPP lock-seal lidding film is a laminated top-sealing film designed primarily for strong sealing to compatible polypropylene food trays and containers. The BOPET outer layer provides optical clarity, tensile strength, dimensional stability, puncture resistance, and a printable surface. The CPP inner layer provides polypropylene-based heat-seal performance.

A lock seal, also called a weld seal or permanent seal, is designed to form a strong bond that is not intended to peel open as easily as an easy-peel lid. It is used when distribution security, tamper evidence, liquid containment, or a durable tray closure is more important than consumer peelability.

HSQY supplies nominal thicknesses from 0.052mm to 0.09mm, roll widths from 150mm to 900mm, and standard 500m rolls with custom conversion available. Anti-fog, custom printing, barrier enhancement, easy-peel CPP, retort CPP, and other functional structures require separate grade selection and validation.

Why Use BOPET/CPP for PP Tray Sealing?

• Strong PP-to-PP sealing interface: The CPP layer can provide a strong heat seal to compatible polypropylene tray flanges.

• High mechanical strength: BOPET supports stable web handling, cutting, printing, and high-speed tray-sealing operations.

• Clear retail presentation: Transparent BOPET and CPP layers can provide high clarity and gloss.

• Puncture and tear resistance: The laminated structure can withstand handling and distribution better than a very light unsupported film.

• Custom printability: The BOPET surface can be treated and printed for branding, product information, and instructions.

• Seal-performance options: Lock seal, hard peel, easy peel, and retort-compatible structures can be developed as separate grades.

• Custom roll conversion: Thickness, width, length, core, winding direction, roll weight, and maximum outer diameter can be matched to equipment.

How the BOPET/CPP Laminate Works

BOPET/CPP Lidding Film Specifications

The table below retains the current commercial values while separating the standard lock-seal grade from optional functional grades. Final guaranteed properties should be stated in the approved technical data sheet, sample approval, and purchase order.

Lock Seal vs. Peel Seal

The current product is positioned as a lock-seal grade. Easy-peel CPP is a different formulation and should be specified separately. Peel or weld performance must be tested on the actual PP tray.

Which Trays Can BOPET/CPP Film Seal?

Barrier Performance: What BOPET/CPP Can and Cannot Do

Standard BOPET/CPP can provide good mechanical protection, moisture resistance, aroma retention, and general product protection. However, a basic two-layer laminate should not automatically be described as a high oxygen-barrier or long-shelf-life MAP film.

For meat, poultry, seafood, prepared meals, or oxygen-sensitive foods, request a high-barrier structure with a defined OTR and WVTR. The tray and lid should be evaluated as one complete barrier package.

Standard CPP, Microwave CPP, and Retort CPP

Anti-Fog and Custom Printing Options

Anti-fog treatment can be added for chilled products where condensation may reduce visibility. The anti-fog side, sealing side, winding direction, storage conditions, and shelf-life requirement should be documented before production.

Custom printing can include logos, graphics, preparation instructions, product information, barcodes, QR codes, batch-code areas, and transparent viewing windows. Confirm print method, artwork, color standards, repeat length, eye mark, registration tolerance, and heat or retort exposure.

Tray-Sealer and Roll Compatibility

Provide the machine brand and model, film width, core inside diameter, maximum outer diameter, roll weight, winding direction, seal-side orientation, eye-mark sensor, tooling layout, operating speed, temperature, pressure, and dwell time.

Before mass production, test web tracking, tension, cutting, seal continuity, seal strength, burst performance, leakage, contamination tolerance, wrinkling, print registration, anti-fog performance, MAP gas retention, and storage performance.

Quality-Control Requirements

• Thickness profile: Controls roll build, stiffness, web tracking, and sealing response.

• Lamination bond strength: Confirms that BOPET and CPP remain securely bonded.

• Seal strength: Must remain within the agreed lock-seal or peel range.

• Seal initiation temperature: Defines the minimum practical sealing temperature.

• Coefficient of friction: Affects unwinding, web transport, and high-speed machinability.

• Optical quality: Includes haze, gloss, gels, scratches, black spots, and contamination.

• Roll quality: Includes edge alignment, telescoping, wrinkles, joints, core condition, and winding direction.

• Barrier data: OTR and WVTR should be reported when shelf-life or MAP performance is claimed.

Typical Applications

• PP ready-meal trays

• Chilled prepared foods

• Meat, poultry, seafood, and deli packaging

• Fresh produce and salads

• Dairy products, desserts, and dips

• Bakery products and prepared snacks

• Liquid-containing meals requiring a strong permanent seal

• Tamper-evident food-service and industrial packaging

• MAP packs using a separately specified high-barrier structure

Explore HSQY's PP food tray range and PP tray sealing film category for compatible packaging options.

Information Required for an Accurate Quotation

1. PP tray supplier, material grade, product code, drawing, or physical sample

2. Tray outside dimensions, flange width, compartments, and fill weight

3. Required lock seal, hard peel, or easy-peel behavior

4. Food type, oil content, filling temperature, storage temperature, and target shelf life

5. Ambient, chilled, frozen, microwave, pasteurisation, or retort process

6. Tray-sealing machine brand, model, tooling layout, and commercial line speed

7. Film thickness, width, length, core ID, maximum outer diameter, roll weight, and winding direction

8. Anti-fog, OTR, WVTR, MAP gas mixture, printing, perforation, or venting requirements

9. Artwork, number of colors, print repeat, eye-mark position, and registration tolerance

10. Required food-contact, migration, quality, and destination-market documentation

11. Trial quantity, annual volume, destination, and requested launch date

Request BOPET/CPP Film Samples and Pricing

Customization Services

• Custom 0.052–0.09mm thickness and tolerance

• Custom 150–900mm roll widths

• Custom roll length, core, roll weight, maximum outer diameter, and winding direction

• Lock-seal, hard-peel, easy-peel, and special CPP sealant structures

• Anti-fog, high-barrier, MAP, microwave-compatible, and retort-grade development

• Flexographic or gravure printing for branding and product information

• Custom eye marks, print repeats, transparent windows, perforation, and venting

• Tray compatibility review, sample rolls, and production-line trials

• Custom cartons, roll labels, pallet marks, and international delivery

Quality and Compliance Documentation

HSQY can provide available quality-management, inspection, and material documents for the approved film grade. Buyers should request the technical data sheet, certificate of analysis, food-contact declaration, migration or compliance reports, OTR/WVTR data when applicable, and roll inspection criteria.

ISO 9001 is a quality-management-system certification and should not be presented as product-specific proof of food-contact safety. SGS or food-contact claims should identify the exact report, laminate structure, food type, temperature, duration, and intended conditions of use.

HSQY International Exhibitions

Production and Packing

Packaging and Delivery

Frequently Asked Questions

What is BOPET/CPP lidding film?

It is a laminated film with a BOPET outer layer for strength, clarity, and printability and a CPP inner layer for heat sealing to a compatible polypropylene tray.

What does lock seal mean?

Lock seal means a strong permanent or weld-type seal that is not designed to peel as easily as an easy-peel lid. Opening may tear the film or distort the tray rim.

Is BOPET/CPP mainly used for PP trays?

Yes. The CPP sealing layer is primarily selected for compatible polypropylene sealing surfaces. The actual tray grade and flange must still be tested.

Can BOPET/CPP film seal PET or CPET trays?

It should not be assumed to seal PET or CPET. Those trays normally require a PET-compatible or universal sealing layer.

Is BOPET/CPP film easy peel?

The product on this page is positioned as lock seal. Easy-peel CPP uses a different sealant formulation and should be ordered as a separate grade.

Is the standard BOPET/CPP film microwaveable?

The current standard grade is listed as not microwaveable. A microwave-compatible grade requires separate film, tray, food, venting, and time-temperature validation.

Is BOPET/CPP suitable for retort processing?

Standard BOPET/CPP should not automatically be used for retort. A qualified retort CPP structure, suitable adhesive, barrier design, and full retort-cycle testing are required.

Is the standard grade freezer safe?

The current page lists the standard grade as not freezer safe. A low-temperature grade should be evaluated separately for impact, brittleness, seal retention, and peel behavior.

Can anti-fog be added?

Yes. Anti-fog can be added for chilled foods where condensation may reduce product visibility. The anti-fog side and storage conditions should be specified.

Can high-barrier BOPET/CPP film be supplied?

Yes, as a separate multilayer structure. Provide the target OTR, WVTR, gas mixture, food type, storage temperature, and shelf-life requirement.

Can the lidding film be custom printed?

Yes. Printing can include logos, product information, instructions, barcodes, QR codes, and transparent windows. Confirm artwork, colors, print repeat, and eye marks.

What thicknesses and widths are available?

The current page lists 0.052–0.09mm thickness and 150–900mm roll width, with custom length and roll conversion available.

What causes a weak lock seal?

Common causes include an incompatible PP tray grade, contaminated flange, insufficient temperature, pressure or dwell time, uneven tooling, poor film tension, or an unsuitable CPP sealant.

What is the minimum order quantity?

The current stated MOQ is 1000kg. Sample and trial quantities depend on stock, width, printing, barrier, and seal requirements.

Can I request samples before bulk production?

Yes, subject to material availability and specification. Send the PP tray sample, machine details, food application, film dimensions, and seal requirements.

About HSQY Plastic Group

HSQY Plastic Group supplies BOPET/CPP lock-seal films, PP tray sealing films, PP food trays, high-barrier packaging materials, plastic sheets, and related products for international B2B customers.

The team can support PP tray compatibility, film-structure selection, roll conversion, printing, lock-seal and easy-peel development, anti-fog and barrier selection, samples, production-line trials, quality documentation, export packing, and international delivery.

Contact HSQY for BOPET/CPP Lidding Film