Cable tie nylon resin: PA66 grades for cable ties, clips and fasteners

Why cable ties are molded from nylon 66

NEMA's cable tie application guide says a majority of cable ties made today are molded from various grades of nylon 6.6. See nylon 6 and 66 grades for the wider family.

• Toughness at the pawl. PA66 is strong for an unfilled resin and gets tougher as it takes up moisture, so the pawl flexes during threading and then holds.
• Flow for long, thin straps. Easy-flow PA66 has low melt viscosity above its melting point of about 260°C / 500°F and fills long strap cavities in multi-cavity tools.
• Fast cycles. PA66 sets up quickly. Lubricated grades feed and release cleanly, and nucleated grades cycle faster still.
• A recognized base resin. General-purpose PA66 grades carry UL yellow cards with UL 94 and RTI values, which Type 11 and 21 tie certifications rely on. The same logic applies to clips; see best plastic for snap fits.

Grade types for ties, clips and fasteners

Tie makers name materials by additive package. The ratings show what each package leads to in one tie maker's material overview.

Finished-tie ratings from HellermannTyton's 2018/19 material overview, which calls them rough guide values. Panduit's 2018 comparison sheet rates its premium nylon 6.6 ties −60°C / −76°F to 85°C / 185°F. A tie's rating comes from its own tests and listing, not the resin data sheet.

Viscosity: what a tie resin spec looks like

Nylon is sold by solution viscosity, not melt flow: relative viscosity (RV) in formic acid by ASTM D789 on many North American sheets, viscosity number (VN) in sulfuric acid by ISO 307 on European ones. The scales do not convert one to one. Ties run on low-viscosity injection grades. In the grades we read, an easy-flow PA66 (BASF Ultramid A3K, as an example) lists VN 150 cm³/g, and one tie brand's published resin spec sets RV about 47–53 in formic acid with VN about 144–153 mL/g, so an easy-flow tie resin near VN 150 can sit at or a little above the RV 40–50 general molding window on our nylon page. Compare grades on one scale, not across them. Extrusion and monofilament grades sit well above this and will not fill a strap. A lot at the top of its window can fill differently from one at the bottom, so ask for the viscosity range on the COA.

Moisture: why dry ties break and how tie makers condition them

PA66 molded dry is stiff with low notched impact. As it takes up water it softens and gets much tougher, so a tie straight off the press can snap at the pawl while the same tie days later bends easily. Two producer sheets show the swing:

Typical values from BASF Ultramid A3K (09/2026) and a 2007 Vydyne 21SPC sheet; trade names are examples only. Our nylon pages give about 2.5–3.5% at 50% RH and 8–10% saturated for PA6 and PA66 together.

• Conditioning and bagging. NEMA's guide says molding can dry out the material, so makers may add water to a sealed bag, usually LDPE, to keep the locking mechanism flexible. A sealed bag should hold its moisture about a year; an opened bag stays flexible in a dry room about 3 to 5 days.
• Moisture moves strength too. More moisture lowers loop tensile strength and raises impact. UL tests certified ties at equilibrium moisture, with stabilization time set by strap thickness.
• Dry the pellets, not the ties. Wet pellets degrade in the barrel, and the ties can look fine and still break. Dry at about 80°C / 176°F, 2–4 hours for PA66 from a fresh bag, to the target on your grade's sheet; published targets run about 0.03–0.2%. Over-drying yellows natural ties. See the drying chart and nylon and moisture.

UL 62275, yellow cards and why a tie file names a resin

UL 62275 and CSA C22.2 No. 62275, based on IEC 62275, cover cable ties for electrical installations. The tie is certified, not the resin, but per UL's 2024 application guide the certification leans on it:

• Types. Types 1 and 11 keep 50% of declared loop tensile strength after environmental exposures; Types 2 and 21 hold the full value; Types 2S and 21S are for primary support and need a declared loop tensile strength of at least 220 N (50 lbf).
• The "1" suffix is about the resin. Types 11 and 21 mean the polymer was also investigated for RTI under UL 746B or CSA C22.2 No. 0.17 and rated at least UL 94 HB.
• Read the yellow card at strap thickness. Cards list UL 94 and RTI by thickness and color. One older general-purpose PA66 sheet shows V-2 from 0.4 to 3.0 mm, but mechanical RTI of 75–85°C / 167–185°F at 0.71 mm and up against 65°C / 149°F at 0.4 mm. See UL 94 ratings explained.
• Outdoor marking. "Resistant to ultraviolet light" is tested on the tie per ISO 4892-2 and applies only when marked on the package.
• Switching resin. A certified tie was evaluated as made from specific materials, so another PA66, even a close equivalent, may need review or retest. Check with your certifier first. Send us the resin and color in your file and we quote that grade, or say plainly that an equivalent needs a file change. See electrical resin sourcing.

Heat stabilizers, UV black and color

• Temperature claims. Standard PA66 ties are commonly rated to about 85°C / 185°F and heat-stabilized ties to about 105°C / 221°F, with some catalog listings at about 115°C / 239°F. See HDT vs. continuous use temperature.
• Copper-halide vs. organic. Additive suppliers describe copper-iodide systems as the long-term leader, to about 180°C / 356°F, but say the halides can promote electrical corrosion. Phenolic packages avoid that but fade above about 120°C / 248°F. Ask which a grade uses if the part touches live components.
• UV black means carbon black. Outdoor ties get their UV life mostly from well-dispersed carbon black, often with a UV stabilizer. A black from another source can look the same and weather worse, so treat it as a material change. See plastics for outdoor UV.
• Precolored vs. concentrate. Fix the carrier, let-down ratio and supplier, approve each color on molded ties, and check that the yellow card covers the color. See masterbatch vs. precolored resin.

Molding, regrind and tolerances

• Melt and mold. Easy-flow PA66 sheets give melt temperatures of about 275–305°C / 527–581°F and mold temperatures around 60–80°C / 140–176°F. One producer warns long barrel residence can permanently embrittle parts.
• Regrind. In cold-runner tools, runners can be a big share of a tie shot. One general-purpose PA66 sheet reports no significant property loss at 25% regrind or less, and its UL card treats up to 50% regrind as the same material. Your tie file or customer may set less. Keep it dry and clean; see regrind limits by resin.
• Pawl tolerances. UL notes small dimension changes in the locking mechanism can let a strap slip. A lot with different viscosity, nucleation or moisture can move shrink, so measure first-article ties from every new grade or source. See a new lot runs differently.
• Specks. One published tie resin spec allows no black specks over 1 mm and no more than 5 per kg from 0.3 to 1 mm. Put your own limit on the RFQ.

How close a substitute can be, and PA66 supply

For uncertified ties and clips, a PA66 with the same viscosity range, lubricant, nucleation, stabilizer type and color system is often a simple trial. Test conditioned ties, not just dry ones. For certified ties, the same grade from the same producer is the clean path. PA66 has tightened at times when its key intermediate ran short; PA6 rarely tightens at the same moment and can suit lower-heat ties, but it needs its own testing and, for certified ties, its own evaluation. See PA66 shortage alternatives, nylon 6 vs. nylon 66 and set up a backup source.

What to put on the RFQ, and what to check on the COA

We do not post prices. Cable-tie PA66 follows the nylon 66 market, with heat, UV, impact and flame packages on top. We quote a specific grade, quantity, package and ship-to city through our supply partners and 22+ partner warehouse locations in the U.S. and Canada, from one gaylord (about 1,000 to 1,600 lb) to railcars, and every prime lot from our suppliers ships with a COA.

• The grade you run now, its data sheet, yellow card file number and recent COAs.
• Polymer and viscosity. PA66, PA6, PA12 or PA11, and the RV or VN range with its method.
• Additive package. Lubricated, nucleated, heat-stabilized (and which type), UV black, impact-modified or flame-retardant, halogen-free if required.
• Approvals. UL 62275 or CSA 62275 file and Type, UL 94 and RTI at strap thickness, and any customer spec.
• Process. Cavities, cycle target, regrind ratio and how you condition ties.
• COA on arrival. Moisture against your molding ceiling, viscosity on the producer's scale and the lot number on every box. See what a COA is.
• Packaging. Moisture-barrier bags or lined gaylords, kept closed until drying; let cold boxes warm before opening. See resin storage and moisture.
• Quantity and ship-to. Gaylord, bulk truck (about 40,000–50,000 lb) or railcar, yearly use and city. See send an RFQ package.

Common questions

If your grade is not listed, tell us what you run. We source commodity, engineering and specialty resins.