Spiral wound tubes are used for many applications such as electrical insulation, thermal or chemical protection in the electromechanical and automotive fields.

They are also chosen for their superior mechanical properties as they ensure a very high resistance to tearing and best dielectric strength.

The spiraling technique consists in coupling a series of adhesive-coated strips, winding them around a mandrel, obtaining a tubular whose electrical, thermal and mechanical characteristics are the sum of the ones of each layer.

Spiral wound tubes are designed and produced according to customer specifications, heat-shrinkable and not heat-shrinkable according to customer request.

They can be supplied in perfectly round or oval form to facilitate insertion and to reduce the overall dimensions.

Their dielectric strength can reach 303kV/mm with reference to the ASTM-D-149-91 test method and are used within a temperature range between -50°C/+300°C.

Our adhesives, carefully selected during our forty years of experience, comply with all REACH and RoHS regulations and guarantee that the original properties of the films used are fully maintained.

Tubes can be cut according to customer needs or wrapped in rolls up to 1000 meters length.

Politubes technical office is available to listen to your needs and offer you tailor-made innovative solutions.

Spiral wound tubes are precision products used in various thermal and electrical insulation applications or to ensure a higher mechanical resistance avoiding any perforation.

The spiral wound technique consists of pairing a series of tapes coated with adhesive and rolling them up in a spiral around a spindle to achieve the tube.

They can be supplied both heat shrinkable and non shrinkable.

Adhesives in all products meet REACH and RoHS standards and guarantee that the original properties of the films used are fully maintained.

We supply:

  • Nomex 410 & 411 tubes and sleeves
  • Nomex/Mylar A tubes and sleeves
  • Nomex/Mylar HS tubes and sleeves
  • Nomex Kapton tubes and sleeves
  • Nomex Kapton Nomex tubes and sleeves
  • Mylar A (Polyester A) tubes and sleeves
  • Mylar HS (Polyester HS) tubes and sleeves
  • Low-shrink Polyester AHS-2LSO tubes and sleeves
  • Non woven tubes and sleeves DM – DMD Class F
  • Mica tubes and sleeves
  • Dielectric Kraft paper tubes and sleeves
  • Kapton (Polyimide) tubes and sleeves

All raw materials and films are supplied by the industry’s world leaders (DuPontTM, Saint-Gobain, Mitsubishi etc.), they are all UL certified and provide excellent electric, thermal, chemical and environmental insulation.

Accurately combined, they can be used in a wide range of temperatures between -50°C and +300°C.

The technology employed by Politubes enables them to produce bespoke coiled tubes with a myriad of features specifically requested by the client: thickness between 0,05 and 0,8 mm, diameters from 1,6 to 150 mm and coloring to name a few.

The possibility to produce multi wall spiral wound tubes allows us to combine inside a single tubes the different electrical, mechanical and thermal properties of each film.

Tubes can be supplied cut in lenght (from 5 mm till 6.000 mm) or rewound in rolls – spools of several hundred meters.

Politubes technical office is available to listen to your needs and offer you tailor-made innovative solutions.

(Mylar – Nomex and Kapton are DuPont registered trademarks)


For more than twenty years Politubes has been offering a unique “spiral wound continuos shrink sleeve” using only heat shrink polyester specific for eletrical purposes (Mylar® HS UL nr E 93687).

This sleeve is supplied in rolls and bobbins of several hundred meters. Its function is:

  • Reduce noise by various decibel in universal washing machine rotors
  • Protect rotor magnets againt dust extending its life
  • Compact rotor surface where there are grooves fixing rotor balancing

This is a multilayer spiral wound continuous shrink tube and this guarantees a superior dielectric strength and mechanical resistance.

The positioning and heat shrink pocess (few seconds) enables extensive use of automatic production equipment.

This hi-tech tube is produced with a spiral wound technology without any overlapping of layers.

We use spiral wound process and not a “flat cigarette” tubes (like we did till 90’s) with a simple overlapping of layers because our customers had asked:

  • a perfect roundness of the tubes that is the only way to guarantee the rotor balancing ; on the other hand overlaps of layers will cause the rotor unbalancing where is the overlap of layers that of course may cause many problems to the motors
  • higher mechanical strenght
  • to avoid breaks and ruptures in the overlapping areas after the heat shrink process

Its perfect roundness improves as well the rotor balancing and even after being heat shrunk, the tube does not interfere with the ventilation duct and magnetic motor flux.

Thanks to perfect insertion automation and instant tube heat shrinking on the rotor ( video below ), the product is perfectly suited for automated production processes.

It is supplied with very low thicknesses thickness ranging between 50 and 75 micron, wound on rolls of several hundred metres long to optimise logistics and reduce transport costs.

Adhesives in all products meet REACH and RoHS standards and guarantee that the original properties of the films used are fully maintained.



Multilayer heat-shrink tubing with high mechanical resistance and high thermal coefficient, to fix and protect against centrifugal forces of all types of permanent magnets applied on the rotors of BLDC brushless motors.

After lengthy Research and Development, in constant contact and comparison with the technical departments of our international customers, Politubes is proud to present an innovative and unique system that enables the manufacturers of brushless motors with permanent magnets to position and secure them effectively, safely and easy to use in automatic industrial productions.

This innovative system eliminates a series of problems well known to brushless motor manufacturers and relating to loss of performance, complications of assembly processes and higher costs, risk of damaging fragile permanent magnets due to use of traditional assembly systems.

The spiral-wound tube is fitted onto the rotor with the magnets in position and is then instantly heat-shrunk, resulting in:

  1. Firm attachment of the magnets to the rotor.
  2. Protection for the magnets from scratches, abrasions and polluting agents.
  3. No danger of cracking or damage to the delicate permanent magnets during the assembly process.

The SHRINK FIBER multilayer tubular high efficiency solution is unique because it includes all the advantages of perfect adhesion even at the edges of the rotor due to the heat-shrink polyester, with the added benefits of extremely high mechanical strength and temperature resistance offered by glass fiber.

As a matter of fact, our solution contains a special composite fiber which exponentially increases the mechanical seal and resistance to temperature compared with simple polyester.

The SHRINK FIBER tubing is inserted on the rotor with the magnets in position and heat shrunk (by using temperatures much lower than Curie point and avoiding any risk of lost of magnetic flux), obtaining strong adherence, even at high revolution speeds. It is also resistant to the thermal shock produced by the motor in lengthy operation, up to 180°C.

Compared with very expensive metallic rotor sleeves, our high efficiency solution avoids eddy-current losses that reduce motors efficiency and that may cause also overheat of electric machines.

Compared with tubing and wrapping which use epoxy resins, the SHRINK FIBER heat-shrink solution offers greater mechanical resistance and avoids lengthy resin activation times in the oven; this increases dramatically our customers’ motors productivity.

In motors which use Bonded magnets (NdFeB or Ferrite) obtained through compression or injection moulding, the SHRINK FIBER tubing protects the magnetic material against corrosion.

As a matter of fact SHRINK FIBER TUBE is easy to be removed if permanent magnets have to be recycled.

Due to its limited thickness, which ranges between 0.19 – 0.35 mm, the SHRINK FIBER sleeve guarantees the correct magnetic flux best of permanent magnets and therefore the best performance of the motor itself.

The system patented by Politubes is simple and efficient and is already an integral part of the production processes of leading companies operating in the electrical motor sector.

The SHRINK FIBER heat-shrink system can be introduced into automatic construction processes and on motor assembly lines, eliminating the critical aspects of traditional tightening systems and the waiting times for adhesives to harden, allowing shorter assembly times and lower electrical motor costs.

Benefits obtained with the Politubes tubing for BLDC brushless motors:

  • High mechanical resistance >100N/mm2
  • High resistance to temperature (- 40°C / + 180°C)
  • Elimination of expensive steel or brass rings and their risk to damage permanent magnets
  • Reduction of motor noise
  • Protection of magnets and increase in motor lifetime
  • No interference with magnetic flux
  • Perfect adhesion and protection at the edges of the magnets
  • Rapid and easy positioning in automated industrial processes
  • Reduced thickness, dimensions and weight
  • Perfect adherence of the tube to the rotor and the magnets
  • Easy to be removed if permanent magnets have to be recycled
  • Low cost

Politubes enlarges its range of heat shrink tubes for brushless motors (SPM surface permanent magnets), with a the new generation of Class F- H, B-Stage epoxy resin coated.

These tubes are produced in three ways:

  1. B-Stage epoxy resin coating inside spiral wound with heat shrinkable polyester outside.
  2. B-Stage epoxy resin coating into a non woven polyester spiral wound with heat shrinkable polyester.
  3. B-Stage epoxy resin coating inside spiral wound with reinforced glass fiber and heat shrinkable polyester outside.

Main benefits after heat shrink and the activation of the B-Stage epoxy resin are:

  • Tubes will have a solid bonding to the metallic tubes with a strong adhesion.
  • Tubes will have a dramatic increase of mechanical strength and hardness.
  • Tubes will get an improved waterproof seal and moisture protection.
  • Tubes bonded to the metallic tubes will have reduced coefficient of expansion.

These tubes can work till class H – 180°C application