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ECMA F40.04.00.00.22

Triangular Clamshell Carton with Rounded Corners

This one-piece triangular clamshell carton holds wedge-shaped products that benefit from a distinct, rounded presentation. Delivered flat, the blank folds by hand into a hinged container with a flat rear spine and a front tuck-and-slit closure.

Because it relies entirely on folding rather than glue, it fits specialty retail, cosmetics, and bakery items where hand assembly is part of the packing routine. The rounded corners soften the profile and reduce the risk of crushed edges during handling.

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  • Order custom samples, short runs, or production runs.
  • US-based. Nationwide service.
  • Nationally competitive pricing & delivery costs.
  • Available in a wide variety of configurations.

At a glance

  • One-piece unglued clamshell design
  • Rounded triangular footprint for wedge-shaped items
  • Front tuck-and-slit closure

Common uses

  • Bakery slices and pie wedges
  • Triangular cosmetic sets or bath bombs
  • Specialty promotional kits
  • Apparel accessories

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Product fits for the rounded triangular clamshell

Bakery and confectionery slices

The wedge shape naturally accommodates pie slices, cake wedges, and specialty pastries. The flat spine provides depth for layered items, while the clamshell opening allows customers to slide the product out without damaging delicate edges.

Specialty cosmetics and bath products

For triangular soaps, bath bombs, or curated cosmetic sets, this carton offers a softer profile than sharp-cornered alternatives. The unglued design means the entire interior can be printed to create a specific unboxing presentation.

Curated gift sets

Small, grouped items can be arranged into a wedge footprint. The rounded corners provide a premium feel for promotional kits or holiday sets that need to stand out from standard rectangular boxes.

Apparel accessories

Rolled ties, socks, or folded scarves fit neatly into the triangular cavity. The front tuck closure keeps the presentation intact on retail shelves without requiring external stickers.

Retail and packing environments

Hand-packed retail operations

Because this carton requires manual folding to form the walls and secure the closure, it fits operations set up for hand assembly. It is not intended for automated cartoning lines.

Boutique and gift channels

The distinct shape stands out on retail shelves dominated by standard rectangles. The flat rear spine allows the carton to be displayed upright or stacked flat, depending on the product's weight distribution.

Limited-edition product drops

For short-run promotions where unboxing presentation matters more than packing speed, the unglued clamshell provides a unique opening experience that reveals the product and interior branding simultaneously.

Situations that point to different carton styles

High-volume automated packing

If your packing line relies on automated erecting and filling equipment, an unglued clamshell will create a bottleneck. Look at a pre-glued crash-lock carton or a standard machine-erected tray instead.

Heavy or shifting products

The front tuck-and-slit closure holds lightweight items, but heavy products that shift during transit may force the flap open. For denser items, evaluate a design with a locking tab or plan to apply an external tamper-evident seal.

Board, print, and closure choices

Board grade and grain direction

The board must be flexible enough to form clean curves around the rounded corners without cracking the print, yet rigid enough to maintain the clamshell's shape. Product weight determines the appropriate caliper.

Food-safe barriers

If the carton will hold bakery items or foods with moisture and grease, the board requires an appropriate barrier coating. Specify whether the product will be wrapped first or placed directly against the paperboard.

Closure security for transit

Determine if the carton will be handed directly to a customer or shipped through a parcel network. Shipped cartons usually require a clear wafer seal over the front tuck to prevent accidental opening.

Interior print visibility

Because the carton is cut from a single flat blank, the interior of the lid and base are fully visible when opened. Decide if two-sided printing is needed for branding or instructions.

Template adjustments for the wedge shape

Die-cut display windows

A window can be cut into the top panel to display the product inside. The window shape can be contoured to match the rounded profile, though a clear film patch may be required for food applications.

Spine depth modifications

The central hinge panel determines the internal depth of the closed carton. This dimension can be expanded for taller items or narrowed for flat products, provided the side walls are adjusted to match.

Front tuck tab shape

The front closure tab and receiving slit can be modified to increase friction. A deeper slit or a wider tab provides a tighter hold for products that might press against the front wall.

Board and packing details

Print layout and interior visibility

Since the carton is cut from a single flat blank, the interior of the lid and base are fully visible when opened. This provides a continuous canvas for branding, instructions, or decorative patterns without requiring a separate printed insert.

Additional notes

Hand-packing labor considerations

Because this is an unglued, folding clamshell, assembly speed depends entirely on manual labor. It is highly effective for boutique volumes or dedicated packing stations, but may not scale efficiently for high-speed automated lines.

Scuff risk on rounded edges

The rounded corners create a smooth profile but can be susceptible to scuffing if the cartons rub against each other during transit. A protective varnish or laminate helps preserve dark or heavy ink coverage.

Related clamshells and trays

B40.21.00.54: Six-Corner Glued Carton with Hinged Lid

Review this option if you need a rectangular hinged-lid carton rather than a wedge-shaped pack.

FAQs

Assembly and Packing

Does this carton require glue to assemble?

No. The carton is delivered flat and folds together entirely by hand. The side walls interlock or fold into place, and the lid secures via a front tuck flap that slides into a pre-cut slit.

Product Fit

Can the depth of the carton be changed?

Yes. The depth is controlled by the central spine panel and the corresponding side walls. These can be scaled up for thicker items or scaled down for slim products during the template design phase.

Materials and Print

Is this suitable for direct food contact?

It can be, provided it is manufactured using a food-grade paperboard and appropriate barrier coatings to resist grease or moisture. Food-contact requirements must be specified before production.

Closure and Security

Will the front flap stay closed during shipping?

The tuck-and-slit closure holds the lid securely for retail display and gentle handling. If the carton will be shipped individually through a parcel network, it should be placed inside a corrugated outer shipper, and a clear wafer seal over the front flap is recommended.

Modifications

Can we add a clear window to the lid?

Yes. A die-cut window can be added to the top panel to display the contents. Depending on the product, this window can be left open or backed with a clear film.

Quantity and Production

How is this carton delivered?

It is delivered flat on pallets. This minimizes shipping volume and warehouse storage space, but requires your team to fold each carton as it is packed.

Display

Does the flat spine allow the carton to stand upright?

Yes, the flat rear spine provides a stable base for vertical display, provided the product's weight is evenly distributed and does not cause the carton to tip forward.

Materials and Print

Can the interior be printed without a separate insert?

Yes. Because the entire clamshell is formed from a single flat blank, the inside surfaces can be printed during the same press run, allowing for interior branding or instructions.

A distinct, rounded profile for wedge-shaped products that prioritizes presentation and easy hand assembly.

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