Insulating Caps: Compact design. Tight tolerances. Superior insulation. Extensive customization options. Easy integration into UL files.
Politubes designs and manufactures a complete range of composite insulating caps engineered to ensure hermetic sealing, precise positioning, reduced footprint, and reliable protection against chemical agents.
The caps are produced by sealing one end of our multilayer spiral tubes and are available in both heat-shrinkable and non-heat-shrinkable versions, always developed and manufactured according to customer specifications.
Politubes multilayer composite tubes are manufactured through a spiral lamination process using premium insulating films such as Mylar® polyester, Hostaphan® 2MSO – 2LSO heat-shrinkable polyester, Nomex® aramid paper, Kapton® polyimide, DMD, and others.
Key Features
Politubes insulating caps are a proven and reliable solution, offering distinctive technical advantages:
- Full customization according to customer specifications
- High performance, tight tolerances, compact dimensions
- Secure locking and hermetic sealing within windings
- Excellent dielectric strength
- Thermal resistance from Class A to Class C
- Outstanding impregnation properties
- Chemical resistance to organic solvents and strong acids
- Excellent mechanical resistance to punctures and tears
- Reduced risk of jamming during insertion
- Resistance to vibration and high-frequency mechanical stress
- Premium raw materials, sourced in cooperation with global leaders (Nomex®, Mylar®, Kapton®, Hostaphan® 2MSO/2LSO, etc.)
- Easy integration into UL files, thanks to materials already listed in multiple UL-certified systems → faster and more cost-effective certification
The IATF 16949:2016, ISO 9001:2015 – TÜV Rheinland, and UL TEOU 2–8 No. E350605 certifications validate the quality and reliability of our manufacturing processes.
Technical Specifications
- Available in circular or ovalized shape for easier insertion and reduced footprint
- Dielectric strength up to 303 kV/mm (ASTM D-149-91)
- Operating range: –50 °C to +300 °C
- Adhesives compliant with REACH and RoHS, preserving the original properties of insulating films
Main Applications
Politubes insulating caps are commonly used in:
- Thermal protector insulation
- Crimp and splice insulation
- Electric motors and compressors
- Motor lead terminals
- Conductor and connection terminals
- Electrical wiring
- Protection of phase cable welds
- Prevention of damage to surrounding parts caused by conductor tips
- In the HVAC (Heating, Ventilation and Air Conditioning) sector, our insulating tubes and caps are used to ensure effective electrical insulation as well as thermal and mechanical protection in various components.
The insulating cap with ultrasonic sealing ensures a hermetic closure at one end, enabling quick and precise positioning, also supported by the material’s heat-shrink properties. This technology delivers excellent dielectric, thermal, and chemical protection performance.
In addition, the cap is highly valued for its superior mechanical properties, providing outstanding resistance to puncture and mechanical stress.
Main Applications
Ultrasonically sealed caps are widely employed in various industrial applications, including:
- Insulation of thermal protectors
- Insulation of crimps and joints
- Electric motors and compressors
- Motor cable terminals
- Conductor and connector terminals
- Electrical wiring harnesses
- Protection of phase cable solder joints
- Prevention of damage to surrounding components caused by conductor ends
- In the HVAC (Heating, Ventilation and Air Conditioning) sector, our insulating tubes and caps are used to ensure effective electrical insulation as well as thermal and mechanical protection in various components.
Materials and Available Configurations
The caps are manufactured from multilayer spiral-wrapped tubes and are available in several configurations:
- Mylar A Caps – Polyester A
- Heat-shrinkable Mylar HS Caps – Hostaphan 2MSO – Polyester HS
- Nomex/Mylar A Caps – Nomex/Polyester A
- Heat-shrinkable Nomex-Mylar HS Caps – Hostaphan 2MSO
- Medium-shrink Polyester AHS Caps – Hostaphan 2LSO
- Polyester fabric/non-woven (DMD) Caps
- Kapton Caps – Polyimide
All raw materials are sourced from leading global suppliers, UL certified, and ensure excellent electrical, chemical, and environmental insulation. Thanks to their composition, they can operate across a wide temperature range: from –70 °C to +280 °C.
Politubes technology also enables ultrasonic sealing on polyimide films, while preserving the intrinsic material properties.
Technical Specifications
- Inner diameters: from 2 to 70 mm
- Thicknesses: from 100 to 500 microns
- Standard sealing length: 3 – 5 mm
- Also available in colored versions or with helical stripes for easy identification
The adhesives used, carefully selected over more than 40 years of expertise, comply with REACH and RoHS regulations and fully preserve the original properties of the insulating films.
Technical Support
The Politubes technical team is available to analyze your specific requirements and provide innovative, customized solutions.
Mylar®, Nomex®, and Kapton® are registered trademarks of DuPont – Hostaphan® is a registered trademark of Mitsubishi
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The insulating cap with spot -dot ultrasonic sealing allows for a localized joint, reducing the weld width compared to traditional ultrasonic sealing performed across the entire tube section.
This solution ensures fast and precise positioning, supported by the heat-shrink properties of the material, while delivering excellent dielectric, thermal, and chemical protection performance.
In addition, the cap is particularly valued for its superior mechanical strength, guaranteeing high resistance to puncture and mechanical stress.
Main Applications
Spot ultrasonically sealed caps are widely used across various industrial sectors, including:
- Insulation of thermal protectors
- Insulation of crimps and joints
- Electric motors and compressors
- Motor cable terminals
- Conductor and connector terminals
- Electrical wiring harnesses
- Protection of phase cable solder joints
- Prevention of damage to surrounding components caused by conductor ends
- In the HVAC (Heating, Ventilation and Air Conditioning) sector, our insulating tubes and caps are used to ensure effective electrical insulation as well as thermal and mechanical protection in various components.
Materials and Available Configurations
The caps are manufactured from multilayer spiral-wrapped tubes and are available in several configurations:
- Mylar A Caps – Polyester A
- Heat-shrinkable Mylar HS Caps – Hostaphan 2MSO – Polyester HS
- Nomex/Mylar A Caps – Nomex/Polyester A
- Heat-shrinkable Nomex-Mylar HS Caps – Hostaphan 2MSO
- Medium-shrink Polyester AHS Caps – Hostaphan 2LSO
- Polyester fabric/non-woven (DMD) Caps
- Kapton Caps – Polyimide
All raw materials are sourced from leading global suppliers, UL certified, and ensure excellent electrical, chemical, and environmental insulation.
Thanks to their composition, they can operate within a wide temperature range: from –70 °C to +280 °C.
Technical Specifications
- Inner diameters: from 2 to 70 mm
- Thicknesses: from 100 to 500 microns
- Standard sealing length: 3 – 5 mm
- Also available in colored versions or with helical stripes for quick identification
The adhesives used, developed through more than 40 years of expertise, comply with REACH and RoHS regulations and fully preserve the original insulating film properties.
Technical Support
The Politubes technical team is available to analyze your requirements and provide customized, innovative solutions.
Mylar®, Nomex®, and Kapton® are registered trademarks of DuPont – Hostaphan® is a registered trademark of Mitsubishi
RELATED APPLICATIONS
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The heat-shrinkable insulating cap with bullnose sealing reduces the closure width, facilitating insertion between copper windings in electric motors and preventing potential damage to the enamel-coated wire.
Thanks to the material’s shrink properties, the cap ensures quick and precise positioning while providing excellent dielectric, thermal, and chemical protection.
The bullnose configuration, with one end closed, allows the cap to lock securely onto the cable terminal, eliminating the risk of slipping or detachment often encountered with conventional open-ended insulating tubes. Furthermore, this closure design maintains the original tube diameter in the sealing area, minimizing overall bulk.
Main Applications
Bullnose caps are used in various industrial applications, including:
- Insulation of terminals in electric motors
- Insulation of crimped connections in electric motors and compressors
- Protection of cable joints belonging to the same phase in windings
- Prevention of damage to surrounding components caused by conductor ends
- In the HVAC (Heating, Ventilation and Air Conditioning) sector, our insulating tubes and caps are used to ensure effective electrical insulation as well as thermal and mechanical protection in various components.
Materials and Available Configurations
Bullnose caps are manufactured from multilayer spiral-wrapped tubes and are available in several configurations:
- Heat-shrinkable Mylar HS Caps – Hostaphan 2MSO – Polyester HS
- Nomex/Mylar A Caps – Nomex/Polyester A
- Heat-shrinkable Nomex-Mylar HS Caps – Hostaphan 2MSO
- Medium-shrink Polyester AHS Caps – Hostaphan 2LSO
- Polyester fabric/non-woven (DMD) Caps
All raw materials are sourced from world-leading suppliers, UL certified, and ensure excellent electrical, chemical, and environmental insulation along with outstanding mechanical performance.
Thanks to their composition, they can operate across a wide temperature range: from –70 °C to +180 °C.
Technical Specifications
- Inner diameters: from 5 to 14 mm
- Thicknesses: from 100 to 500 microns
- Standard sealing length: 4 – 5 mm (custom lengths available upon request)
- Also available in colored versions or with helical stripes for quick identification
The adhesives used, carefully selected and refined over more than 40 years of experience, comply with REACH and RoHS regulations and fully preserve the original properties of the insulating films.
Technical Support
The Politubes technical team is available to assess your requirements and provide tailored, innovative solutions.
Mylar®, Nomex®, and Kapton® are registered trademarks of DuPont – Hostaphan® is a registered trademark of Mitsubishi
RELATED APPLICATIONS
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The semi-cap is designed with a radius sealing that facilitates the insertion of gaskets on mechanical parts with sharp edges, preventing potential damage.
Thanks to this construction feature, semi-caps ensure quick installation, reliable protection, and secure positioning during assembly.
Main Applications
Semi-caps are widely used in various industrial applications, including:
- Insertion and protection of gaskets and O-Rings in valves of internal combustion engines
- Assembly on engine heads and valve guides
- Mechanical assemblies requiring thickness adjustment
- Protection during the insertion of Dunlop, Schrader, and Presta valves into tires, preventing damage to the tire caused by the metal components of the valve
The radius sealing not only protects components during insertion but also reduces the risk of the semi-cap slipping once in place.
Materials and Technical Specifications
- Material: Semi-heat-shrinkable Polyester AHS – Hostaphan 2LSO
- Inner diameters: from 5 to 12 mm
- Thicknesses: from 75 to 150 microns
- Lengths: greater than 7 mm
- Radius sealing length: from 2 to 5 mm
- Also available in colored versions or with helical stripes for quick identification
The adhesives used, carefully selected and refined over more than 40 years of experience, comply with REACH and RoHS regulations and ensure full preservation of the original insulating film properties.
Technical Support
The Politubes technical team is available to assess your requirements and provide customized, innovative solutions.
Hostaphan® is a registered trademark of Mitsubishi