Technical Information

Since Japan's first installation of an industrial electron beam generator on Sumitomo Electric's premises in 1964, the company has put its resources into developing and commercializing various products using its original electron beam irradiation technology for plastics.

When irradiated with an electron beam (a flow of electrons that are accelerated in a vacuum using high voltage), certain plastic materials develop cross-linkage (a reaction that creates new chemical bonds between plastic molecules). As a result, the heat resistance, shape-memory effect, oil/chemical resistance, and various other properties of the plastic are improved.


The products shown in this catalog have not been developed or commercialized for use in medical or other special fields which are associated (directly) with human life and the body. If you intend to use these products in a special field related to human life or the body, be sure to carry out preliminary safety testing of the particular products by yourself and use them at your own responsibility.

The product data in this website represent typical values measured from a single product. Features of the products also represent their general physical properties. These data do not guarantee the safety of the products in individual applications. Therefore, you are required to unconditionally check by yourself that the particular products conform to the safety requirements of your particular applications. Please understand that Sumitomo Electric and its affiliates do not assume any responsibility for any accidental or indirect loss.

Since the sealing properties of SUMITUBE and IRRAXTUBE with adhesive lining differ depending on their use conditions, first check their sealing properties under your particular use conditions.

As for the product appearance, a small wound and irregularity, a dirt, the unevenness of the hue may be seen. These are not malfunctions in being used for main use such as insulation protection, mechanical protection or bundling. Please contact us in case you require special appearance quality.

Depending on the storage condition, some compounding agents may precipitate on the surface of the tubes.

Comply with the use conditions specified in each safety standard.

Special care is required when shrinking a tube over an object containing a sharp bend, corner, protrusion, or edge. The tube may split.

Please note that the contents of this website are subject to change without prior notice.


IRRAX is Sumitomo Electric’s trade name for heat-resistant plastics and shape-memory plastic produced by Sumitomo Electric Fine Polymer, Inc. The molecules of these plastics are cross-linked (given a 3D network structure) by electron beam irradiation, thereby enhancing the reliability in use of these plastics, which have superior heat resistance and liquid (oil and chemical) resistance.

Designation of UL and CSA certified products

If inspectors from UL and CSA require you to show a UL or CSA certificate for a specific tube meeting the requirements of these standards, show them the mark on the surface of each tube or the product label on the package. Sumitomo Electric has introduced a Re-Examination Service system to be followed up by UL and CSA. Therefore, inspectors will never require you to use special tags such as those required for electric cables.
In the past, these safety standards made it compulsory for manufacturers to indicate their company name, temperature rating, and other items on each tube. Though these standards do not require these items to be indicated any more, Sumitomo Electric still indicates these items on each tube as in the past.
UL has disclosed its UL-certified products lists on its website, permitting us to copy them and use the copy as a certificate of authorization. Sumitomo Electric provides copies of these lists for our products that are UL-compliant, and copies of the Certification Record for our products that are CSA-compliant.

VW-1 flame retardance rating

“VW-1” is a flame retardance rating specified by the UL224 standard and CSA standard. Only products that have passed a vertical wire flame test are rated at VW-1. In the vertical wire flame test, signified by the acronym VW, the test specimen (tube) with a wire inside is held vertically and burnt. For a VW-1 rating, the flame must go out within one minute. The CSA standard originally specified “OFT” flame retardance rating for tubes. However, this standard adopted the same tube test method as that specified by the UL224 standard and subsequently the rating designation was changed to VW-1.
Some of our customers ask us about the UL94 V-0 flame retardance rating. UL94 is a safety standard that specifies the flame resistance of plastic materials used for making machine parts. A sheetlike specimen is used for the evaluation test. Accordingly, UL94 does not cover the tubes and their auxiliary products shown in this website.

Maximum allowable continuous working temperature

For the maximum allowable continuous operating temperatures of products that comply with safety standards (UL, CSA, SAE-AMS, etc.), this catalog shows the highest temperatures specified in these standards. For the aging resistance and other characteristics of the products manufactured by Sumitomo Electric Fine Polymer, Inc., the company has designed the product specifications after referring to the related UL requirements. For products with an inner adhesive layer (SUMITUBE and IRRAXSLEEVE with an adhesive lining), this website shows the maximum allowable continuous operating temperature that has been determined from the material characteristics of the outer layer. Note that these products may be dislocated due to melting of the adhesive if they are exposed to high temperatures.

Color tone

Product color tones have originally been designed according to Sumitomo Electric’s standards. Note that color tone differs depending on the product model. However, some product models are colored according to the requirements of applicable safety standards.

Characteristics of tubes of double layer construction (waterproof)

The table below shows the characteristics of two (PVC) lead wires, A and B, with their joint shielded with SUMITUBE W3C or SUMITUBE O2C. SUMITUBE W3F2 and SUMITUBE O2B2 have the same waterproof as the above two tubes.

Shrink ratio

The shrink ratio is defined as follows:

Most of the products shown in this website are designed so that, after they have shrunk completely, their inside diameter will decrease to one half or less of their original inside diameter. This means that the shrink ratio is 50% or more. The larger the shrink ratio, the more noticeably will the products show a reduction in their inside diameter. Products that will reduce their inside diameter to one third, a quarter, or less are also available.

Longitudinal change ratio

Longitudinal change
ratio is defined as

Assume that an originally 100mm long tube reduces in length to 96mm after complete shrinkage, then the longitudinal change ratio of this tube is calculated to be -4%, as follows:

  Longitudinal change ratio (%)=(96-100)/100 × 100= -4(%)

Assume that a product with a longitudinal change ratio of "0±5%" is heated to shrink completely. Then this product will reduce its length by a maximum of 5% or will increase its length by a maximum of 5%.

The tube may not shrink as completely as it shrinks when heated as a single piece (according to the longitudinal change ratio), depending on the surface characteristics of the wire being sheathed, the clearance between the wire and tube, tube heating temperature and time, and other factors. Determine the length of each heat-shrinkable tube properly according to your use conditions.

Tube shrinking method and cautions to be observed during tube heating

Insert the object to be sheathed in a tube whose inside diameter is larger than the outside diameter of the object, and heat the tube using one of the following methods. The tube will immediately shrink tightly over the object.

-Heating with an industrial heating tool
Heat the object along its circumference from one end to the other or from the center to both ends.
-Heating in a high-temperature atmosphere using a thermostatic oven or heating furnace
-The shrinkage completion temperatures shown in this website represent the temperatures of the tubes themselves. The ambient temperature around the heating spot is preferably 20 to 50℃ higher than the tube temperature. However note that the tube heating temperature and time should be controlled according to the specific heat and thermal conductivity of the object being sheathed and the ambient temperature. Determine the optimum tube heating conditions while checking how each tube shrinks.
-Please note that liquid may remain between the object and the tube if the tube has been heated by immersing in high temperature liquid such as hot water.
-The tube may develop cracks when heated locally if the surface of the object being protected has a protrusion or sharp edge or if the tube has been cut non-uniformly and the cut surfaces contain defects such as slit or diagonally cut section. Although the tube can be used to protect an object whose cross section is angular or irregular rather than circular, a gap may be produced between the tube and any concave surface after the tube is shrunk.

Shrinking a two-layer tube and precautions for use

-When shrinking a two-layer tube with adhesive lining, it is recommended to heat the tube until sufficient adhesive is visible at both tube ends so as to ensure that the tube is reliably waterproof.
-When heat-shrunk, the tube may slip down on the smaller outside diameter side of the object or may become dislocated by a bending load or other external force, resulting in deterioration in the sealing properties of the tube. Before using the tube, always check whether the sealing properties of the tube meet your use conditions.

Tube storage conditions and natural shrinkage of tubes

Heat-shrinkable tubes will not shrink prematurely as long as they are stored at a temperature lower than the shrinkage start temperature. However, we recommend that you store them in a cool dark place. Avoid exposing them to direct sunlight.
SUMITUBE V tends to start shrinking at near 40℃ due to the characteristics of the raw material, polyvinyl chloride. Store this tube with special care.

RoHS and ELV Directive

-What is RoHS?
RoHS, which stands for "Restriction Of the use of certain Hazardous Substances in electrical and electronic equipment," is an EU directive issued to restrict the specific hazardous materials found in electrical and electronic products. After being put into effect, this directive bans intentional use of the regulated substances in manufacturing electrical and electronic products to be sold in the European market or inclusion of these substances in these products at concentrations higher than the specified threshold levels, though this directive has set some exemptions. If electrical and electronic products contain any of these hazardous substances at a concentration higher than the regulated threshold level, the governing EU authority may direct the related manufacturer to withdraw such products.

The regulated substances and the date of enforcement are as follows:
Regulated substances (1)lead (2)mercury (3)cadmium (4)hexavalent chromium, and certain halogenated flame retardants ((5)PBDE (6)PBB)
Date of enforcement July 1, 2006 (EU directive: 2002/95/EC)
Date of promulgation of amended directive July 21, 2011 (EU directive: 2011/65/EU)
Sumitomo Electric has actively implemented measures necessary to comply with the RoHS directive. In this website, a check mark with “RoHS directive” has been added to each header on RoHS-compliant products to express more clearly that these products comply with the directive. Most of the products that are not shown in this website comply with this directive. However, contact Sumitomo Electric on a case-by-case basis for compliance of the product models in which you are interested.
-What is the ELV directive?
ELV, which stands for “End of Life Vehicle,” is an EU directive that was passed in May 2000 and came into effect in October 2000. The objective of this directive is to facilitate the recycling of end of life vehicles, thereby reducing waste products and mitigating their effects on the environment. The ELV directive restricts the use of almost the same substances as those regulated by the RoHS directive, excepting the halogenated flame retardants.
Regulated substances (1)lead (2)mercury (3)cadmium (4)hexavalent chromium
Date of enforcement October 2000 (EU directive: 2000/53/EC)

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