Shipping Container Door Rubber – Type J – Container Corner

Price is for 1 piece – corner 30 x 30 cm!

What is a type J container door corner rubber?

The 30 x 30 cm type J shipping container door rubber is a special, pre-shaped part made of dense rubber (most often EPDM) that is used to perfectly seal the 90° corners of container doors. It is a key element of the sealing system of ISO containers, allowing them to be hermetically sealed and protecting the transported cargo from water, dust, pests and extreme climatic conditions.

This part is designed for easy and efficient replacement of the most stressed parts of the seal, which significantly extends the life of the entire container and minimizes maintenance costs.

The 30 x 30 cm type J corner rubber is a small but absolutely crucial part of every shipping container. Thanks to advanced materials (EPDM), precise manufacturing and standardization, it enables safe, dry and hygienic transport of goods of all categories around the world. Its regular maintenance and timely replacement are essential for the reliability and long life of not only the container itself, but also your business.

Method of transporting goods

Possibility to send by transport service. The price for transport depends on the quantity ordered and the specific country.

If you are interested, please send an inquiry via the order form, we will send you a price offer for transport. Please always include the delivery address in the order so that we can calculate the transport costs and the required number of pieces.

All information, services, prices, etc. are subject to change.
The price list is indicative, we always charge according to the actual situation – current market prices.
We offer all spare parts for shipping containers. Opening of shipping container at great prices. Spare parts for containers are usually in stock, can be sent immediately. The quantity in stock is always on request.

Technical terminology and identification

• Czech designation: Corner rubber, corner type J seal, corner part of container door seal
• English designation: J-Type Corner Gasket, J-Seal Corner, Molded Rubber Corner, Container Door Gasket Seal Corner
• Code designation (OEM):
• CIMC-D26-03D : type J profile, size 300×300 mm
• Manufacturing standard: GB/T 15846-2006 (Chinese national standard for container sealing)
• Category: ISO Dry Container Parts, Shipping Container Door Gaskets

Installation and repairs – step by step

Typical installation of a corner seal includes:

• Disassembly of fastening strips – removal of rivets or screws around the corner.
• Cutting out the damaged seal – clean straight cut for perfect connection.
• Cleaning the substrate – removal of corrosion, old glue or dirt.
• Inserting a new corner – fitting the pre-shaped part into place.
• Gluing joints – use of glue intended for EPDM (e.g. cyanoacrylate glue, type PERMABOND 105).
• Fixing with strips and rivets – fastening the seal to the door frame.
• Leak test – ideally with a light test, or with a water shower.

Manufacturers’ recommendations:

• Always use only glues intended for EPDM.
• Install at temperatures above 5 °C.
• After installation, leave the joint without mechanical stress for at least 1 hour.

Maintenance, service life and recommendations for operators

Service life

The average service life of a quality EPDM corner rubber is 8–12 years (under normal operation and maintenance).

In extreme conditions (tropics, arctic, frequent washing with salt) it may be reduced to 6–8 years.

Regular maintenance

• Visual inspection : 1x every 6 months, look for cracks, discoloration, hardening.
• Cleaning : Remove dirt, salt, chemical residues. Use only gentle cleaning agents (no aggressive solvents!).
• Timely replacement : Replace damaged seals immediately to prevent damage to cargo and corrosion of the door frame.

Possible defects and their consequences

Physical and material properties

Manufacturing process – How is a corner seal made?

1. Material selection

Only high-quality EPDM with high density and certification according to GB/T 15846-2006 is used.

The material is often subjected to ozone and UV resistance tests.

2. Extrusion

Long straight segments of the “J” profile are created by extruding a heated rubber compound through special nozzles.

The result is a homogeneous, non-porous profile with precise dimensions.

3. Corner molding

Corners (300×300 mm) are manufactured by molding into metal molds, which ensures a precise 90° angle and a seamless surface.

This is followed by vulcanization, where the material is heated above 150°C and achieves final elasticity, shape memory and surface resistance.

4. Final finishing and inspection

Each piece is visually inspected, hardness, strength, dimensions and surface finish are measured.

Manufacturers with IATF 16949:2016 certification (such as Hebei Shida Seal Group) provide PPAP Level 3 documentation for OEM customers.

Key functions and importance in container transport

Primary function – hermetic sealing

• Watertightness : The corner-sealed joint prevents water from entering during rain, waves, condensation and protects goods from corrosion and mold.
• Airtightness : Prevents the ingress of dust, sand and dirt during transport and storage.
• Pest protection : Effectively prevents the ingress of insects and rodents, which is especially important in international transport and food transport.
• Maintaining isothermal properties : For refrigerated containers, perfect sealing is key to maintaining temperature and reducing energy losses.

Secondary meanings

• Compliance with inspection and certification requirements : A functional seal is a condition for the validity of the CSC plaque for safe international transport (CSC – Convention for Safe Containers).
• Extends container life : Properly sealed doors minimize corrosion and reduce the frequency of repairs.

Types and applications – where and how corner seals are used

Use by container type

Possible profile variants

• J-Type (most common) : Suitable for most ISO containers; optimal for dry and refrigerated applications.
• C-Type, JC-Type, H-Type : Used in some special applications and container modifications – must be verified according to OEM specification and door type.

Compatibility and modularity

Parts are manufactured according to ISO dimensional standards, which allows compatibility across container manufacturers (CIMC, Maersk, Singamas, and others).

Corner parts are always usable in combination with straight type J segments.

Standards, certifications and industry standards

• GB/T 15846-2006 – Chinese national standard for rubber seals of container doors, specifying quality, dimensions and testing methods.
• IATF 16949:2016 – International (automotive) standard for quality management, applied to manufacturers with emphasis on traceability, process control and batching.
• PPAP Level 3 – Documentation for OEM customers, including complete approval documentation of the manufacturing process.

Comparison with other materials and profiles

EPDM vs. PVC and natural rubber

Conclusion:
EPDM is the most suitable material for long-term reliable sealing in demanding conditions.

Sealing location diagram on container doors

30×30 cm corner rubbers are used in each corner, the rest is made up of straight segments of the J profile.

Related terms and additional information

• EPDM : Synthetic rubber with extreme resistance, also used in the automotive and construction industries.
• Extrusion : The process of extruding material into the desired shape.
• Vulcanization : The process of heat curing rubber.
• CSC plaque : International certification of container safety.
• Retaining strips : Metal strips holding the seal on the doors.
• IATF 16949:2016 : Certification of the production quality management system, mainly in automotive.