Welded Soft Cooler with Airtight Zipper – 420D TPU High-Frequency Welded Cooler Bag, SL-I139

At a Glance

Product Description

SL-I139 is a welded soft cooler with an airtight zipper, measuring 36 × 26 × 36 cm, holding 20 liters, or around 24 standard 330 ml cans without ice, and weighing 2.2 kg. The shell is 420D TPU, and every seam on the shell, the food-grade TPU liner and the attachment patches is high-frequency welded. Between shell and liner sits 25 mm of closed-cell foam on all sides including the lid. The top closes with an airtight waterproof zipper. The front and back each carry two webbing daisy chains with contrast bar-tacks, ending at the base in moulded D-ring anchors, and a black wear band protects the base. Webbing tote handles cross over the lid, each end has a grab handle on a welded patch with a moulded hook anchor, and a detachable shoulder strap with a padded shoulder section clips on with carabiner-style snap hooks. Standard colours are white and green.

What High-Frequency Welding Changes

A sewn cooler is held together by thousands of needle holes, sealed with tape on the inside. Over a season of ice, melt-water and temperature swings, the tape adhesive softens, water wicks through the holes into the foam, and the cooler begins to lose insulation and hold odour. High-frequency welding joins the TPU panels by melting them together with radio-frequency energy under pressure, so the seam becomes a single layer of material with no holes and no tape. On SL-I139 this applies to the shell, the liner and every patch that carries a handle, a daisy chain or an anchor: the webbing is sewn only to its own patch, and the patch is welded to the body. Nothing is stitched through the waterproof wall.

Airtight Zipper

A standard zip, even a water-resistant one, leaves a gap between the teeth that air and water can pass through. An airtight zipper closes with interlocking, sealed teeth that form a continuous barrier along the full length of the opening. Combined with the welded body, it turns the cooler into a sealed chamber: melt-water cannot leak out however the cooler is placed, rain and spray cannot get in, and warm air cannot leak in along the closure. With the zipper closed, SL-I139 is rated IPX7, verified by full water-immersion test, 2+ hours. It is not rated for depth exposure.

420D TPU Shell

420D TPU is a nylon base fabric coated with thermoplastic polyurethane. The 420D base gives tear and abrasion strength for decks, truck beds and rough ground; the TPU coating is what allows the fabric to be welded, keeps it flexible in cold weather and wipes clean without absorbing stains. The heavier fabric and 25 mm foam account for the cooler's 2.2 kg weight, which is the trade-off for a body that holds its shape and stands up to years of use.

Cold Holding

Packed with ice, closed and kept out of direct sun, the cooler holds ice for approximately 40 hours in our trials at 25 °C ambient. Results change with ambient temperature, sun exposure, how often it is opened and whether the contents were chilled before loading.

Engineering Specifications

Material Specifications

Functional Specifications

Customization and OEM

Packaging Specifications

Recommended Use

Boating, fishing, overlanding, camping, beach days and tailgates where a cooler has to stay sealed, take rough handling and last for years. Suitable for drinks, food, bait and ice. Not intended for depth exposure.

Quality Inspection Standards

Every production run is checked at IQC, IPQC and OQC. The suite covers load testing to 1,500 cycles, zipper fatigue to 3,000 cycles, tensile and bonding strength on every welded seam and attachment patch, pull tests on moulded anchors, abrasion on the base band, colour fastness and colour difference against the approved sample, and full water-immersion testing on finished coolers. Because the zipper is airtight, every unit also goes through our customer inspection procedure — unboxing, vacuum extraction, 24-hour static rest and air-leak determination — which finds pinhole weld faults and zipper seating issues that a spray test cannot. Third-party inspection by SGS or QIMA can be arranged at the buyer's cost.

Product Highlights

420D TPU shell, liner and attachment patches all high-frequency welded, with no stitching through the waterproof wall. Airtight zipper that makes the cooler a sealed chamber, IPX7 and leakproof in any orientation. 25 mm closed-cell foam for about 40 hours of ice under stated conditions. Four daisy chains with D-ring anchors, tote handles, end handles and detachable padded shoulder strap. Every unit air-leak tested before shipment. White or green, MOQ 300.

Printing and Logo

Screen printing suits solid one- to three-colour marks on TPU and resists UV and salt. Heat transfer handles multi-colour artwork. Welded TPU patches and raised silicone prints give a tonal, textured mark that matches the welded construction. Logos sit between the daisy chains, clear of the zipper. Webbing, bar-tack and liner colours can be matched to the brand. Artwork is required as vector files; a digital placement proof is returned before sampling.

OEM / ODM Capability

Sealock has manufactured insulated and waterproof gear for over 20 years, with factories in Guangdong, China and Ho Chi Minh City, Vietnam — the second site giving brands a non-China origin option where tariff exposure matters. We hold ISO 9001, BSCI, SMETA, Higg, GRS and SCAN certification, and produce insulated products for brands including STANLEY, Hydro Flask and CORDOVA.

High-frequency welding is the core process on this cooler, but sewn construction is an equally mature in-house capability, used here for the daisy chains, handles and shoulder pad. Most demanding requirements can be met, from a colour and logo change to heavier fabric, VIP insulation, new sizes or a full redesign; complex development with new tooling adds time to the first sample cycle, which is worth planning for early.

Related Products

• Tall Soft Cooler – Holds Bottles Upright, Airtight Zip
• Cooler Shoulder Bag – Airtight Zip, Padded Strap
• Soft Cooler Bag 15L – 30 mm Insulation, Airtight Zip
• Boat Cooler Bag – White Airtight-Zip Soft Cooler
• Custom Soft Cooler – OEM & Private Label

FAQ

What is the minimum order quantity?

300 pieces per colour.

What does it cost?

Price depends on quantity, fabric, insulation, accessories and logo method. Send your specification to info@sealock.com.hk and we will quote within one working day.

Can we put our own logo on it?

Yes. Screen print, heat transfer, welded patches and raised silicone prints are all available, with Pantone matching on shell, webbing and liner.

What is the difference between welded and sewn coolers?

Sewn coolers rely on taped needle holes, which can leak as the tape ages. Welded coolers join the panels into a single layer of material with no holes, so they stay leakproof and keep their insulation dry for much longer.

What does an airtight zipper do?

It seals the opening completely, so water cannot get in or out and warm air cannot leak in along the closure. With the welded body, it makes the cooler IPX7 and leakproof in any orientation.

Why does it weigh 2.2 kg?

The 420D TPU shell and 25 mm foam are heavier than thin-walled coolers, in exchange for strength, shape and longer ice retention.

How many cans does it hold?

About 24 standard 330 ml cans without ice, or about 16 with ice.

How long does ice last?

Approximately 40 hours in our trials at 25 °C ambient, packed with ice, closed and out of direct sun.

How do I look after the airtight zipper?

Rinse off salt and sand, lubricate the teeth occasionally with a silicone-based stick, never force it closed over grit, and store the cooler with the zipper open.

What is the lead time?

Samples in 7–15 days. Production is 30–35 days after sample approval, from either the China or the Vietnam factory.

Request a Quote

Send your target quantity, colour and logo artwork to info@sealock.com.hk. We will return a quotation with sample lead time and packaging options.