Selecting a Material for Your Application

Grayline offers tubing manufactured from a variety of materials, including flexible PVC, TPV (thermoplastic vulcanizate), TPE (thermoplastic elastomer), polyurethane, polyethylene, nylon, fluoropolymers, rubbers, and silicone.

There are many material options to consider when selecting flexible polymer tubing. As might be expected, the polymer from which flexible tubing is manufactured is the single most important factor in determining the final mechanical, electrical, chemical and thermal properties of the tubing. However, the processing conditions under which the polymer is manufactured into tubing also affect the final properties.
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For general guidance in determining which material is best suited to your specific application, please review the information contained on our website, use our Tubing Selection Guide, or simply contact Grayline for assistance:

CLICK HERE TO TRY OUR TUBING SELECTION GUIDE

Read Grayline's White Paper, "Choosing the Right Heat Shrink Product for the Job - A User's Guide to Heat Shrink Tubing"

PREFER TO SPEAK WITH A TECHNICAL SALES REPRESENTATIVE? CLICK HERE TO EMAIL US, OR PHONE GRAYLINE AT 1-800-669-7986

One broad classification that can be made among polymers is thermoplastic vs. thermosetting. A thermoplastic polymer, such as PVC, can be repeatedly melted and solidified. However, a thermoset polymer, such as crosslinked polyolefin, cannot be reprocessed once it is irreversibly "set" by a post-extrusion process called cross-linking. Cross-linking involves the formation of three-dimensional covalent bonds between long molecular chains, and it improves certain properties such as heat resistance and tensile strength. A simple analogy is a piece of yarn, with each fiber in the yarn representing a long polymer chain of molecules. Although there is some slight resistance to doing so, individual fibers can be pulled relatively easily from the piece of yarn. However, if the yarn is soaked in glue and subsequently dried, the individual fibers will now be securely joined together, and they can no longer be separated from one another. The cross-linking process is analogous to this gluing process, permanently joining the long polymer chains together.

PVC tubing should be your first consideration for either heat shrinkable or non-heat shrinkable tubing. For many applications, PVC is the optimum material choice, and Grayline offers a number of different PVC compounds.

With specific regard to heat shrinkable tubing, heat shrinkable PVC is less expensive than heat shrinkable polyolefin, and suits many applications quite well. In addition to the associated cost savings, it has excellent clarity in its clear form, it is easy to custom color match, and it has good UV, chemical and abrasion resistance. Polyolefin heat shrinkable tubing does offer a wider operating temperature range and slightly less longitudinal shrinkage. In more demanding applications, the advantages of polyolefin may warrant the additional cost.

For those applications warranting concern about potential toxic and corrosive smoke emissions during combustion of materials containing halogen compounds, Grayline offers halogen-free flexible tubing. Halogen compounds contain any of the five halogen elements (Fluorine (F), Chlorine (Cl), Bromine (Br), Iodine (I) or Astatine (At)). The use of halogen-free tubing is becoming more common in enclosed spaces occupied by humans, such as airplanes, subways, and trains, as the smoke emitted is far less toxic. Halogen-free tubing is also finding applications in areas housing sensitive or critical electronic equipment, such as security or communication centers, in order to minimize damage caused by corrosive smoke emissions. Grayline HF100 flexible tubing is flame-retardant yet halogen-free. Grayline also offers other halogen-free products that are not flame retardant.

Click here for more information about halogen-free tubing.

Plasticizers are utilized in the formulation of flexible PVC compounds in order to add softness and flexibility. One type of plasticizer used in PVC is phthalates. Commonly used phthalate plasticizers are DOP (Dioctyl Phthalate), DEHP (di-2-ethylhexyl phthalate) and DINP (Di-isononyl phthalate) and DIDP (Diisodecyl phthalate).

Because of regulatory and health concerns, the use of certain phthalate plasticizers is being restricted in some applications. In response to these concerns, Grayline offers three classes of non-DEHP/non-phthalate tubing.

Non-DEHP Tubing - trace level limit not specified
Material is formulated with a plasticizer other than DEHP, but trace levels of DEHP are not controlled.All Grayline tubing products are Non-DEHP.

Non-Phthalate Tubing - trace level limit of 1000ppm
Material is certified to contain no more than 1000ppm (0.1%) total phthalate content.

Non-Phthalate Tubing - Phthalate content must be zero
Material cannot contain any trace levels of phthalates. For these applications, non-PVC materials are required.

The acronym stands for Restriction Of Hazardous Substances. RoHS is a European Union law (EU Directives 2002/95/EC, 2011/65/EU (RoHS2) & 2015/863/EU (RoHS3)) that prohibits the use of lead, mercury, cadmium, hexavalent chromium, polybrominated biphenyls, polybrominated diphenyl ethers, and four phthalate plasticizers in electrical products sold in the EU. All Grayline tubing is compliant and does not contain the prohibited substances.

REACH (Registration, Evaluation, Authorization and Restriction of Chemicals) is a European Union regulation (2006/1907/EC) that requires that chemical substances used or imported into the EU be registered, evaluated and authorized for specific uses. As a manufacturer of “articles”, Grayline is not required to registerany substances.

The regulation also defines Substances of Very High Concern (SVHC’s) which must be reported to users. As of June 2024, there are 241 SVHC substances defined. Only one of these substances, the UV stabilizer UV-328, is used in some of Grayline’s PVC compounds. See Grayline’s REACH policy for more details.

In many cases, the tubing selected must meet industry specifications such as UL/CSA, ASTM, AMS, EU, USP, NSF, FDA, 3-A, as well as various Automotive and Military Specifications.

For an explanation of specific tubing related specifications, see one of the following "Learn About Tubing" sections:

Common Electrical Tubing Specifications
Common Medical/Food & Beverage Tubing Specifications
Common Braided Sleeving Specifications
Common Environmental Specifications Applicable to Tubing

The image below shows the approximate relative costs for various electrical grade PVC tubing materials.