To formulate a flexible PVC wire insulation with DOA, plasticize K-67 to K-70 resin either with DOA alone at 30–40 phr or with DOA blended into a primary such as DINP or DOTP. Then add a calcium-zinc heat stabilizer, a lubricant and little or no filler. DOA is there for cold flexibility, so its level follows the cold-bend temperature the cable has to pass.
DOA is also more volatile than DOP or DINP, which limits the compound to the 70 °C class.
Starting Formulation
A DOA cable compound can be as simple as resin, DOA, heat stabilizer and lubricant. An industry compounding guide gives that recipe for low-temperature cables, with DOA (or DOS) as the only plasticizer. The table shows it beside the same guide’s general-purpose insulation recipe.
| Ingredient | Low-temperature cable (phr) | General-purpose insulation (phr) |
|---|---|---|
| PVC resin | 100 (K-70) | 100 (K-67) |
| DOA or DOS | 30–40 | — |
| DOP | — | 40–70 |
| Chlorinated paraffin oil | — | 10–20 |
| Heat stabilizer | 4–8 | 4–8 |
| Lubricant | 1–3 | 1–3 |
| Calcium carbonate | — | 0–10 |
For an insulation, use the low-temperature recipe.
Choosing the Primary Plasticizer
Blend DOA with DINP or DOTP wherever DEHP (DOP) is restricted, and with DOP only where it is not. You can also run DOA as the only plasticizer, as the compounding guide’s low-temperature cable recipe does.
The partner depends on the market and on the cable’s other requirements:
- DOP: the general-purpose cable plasticizer where DEHP is not restricted. In the EU, RoHS has limited DEHP (DOP) since 22 July 2019 (22 July 2021 for medical devices and monitoring and control instruments) to 0.1% by weight of each homogeneous material in electrical and electronic equipment. That includes cords below 250 V that connect equipment to the outlet or to each other.
- DINP or DOTP: neither is on the RoHS restricted list, so either one replaces DOP as the partner wherever DEHP is restricted.
- TOTM or DIDP: the heat-resistance plasticizers, used where durability matters more than low-temperature properties. Adding DOA to them trades part of that heat resistance for cold flexibility.
How Much DOA to Add
Set the DOA level from the cold test the cable has to pass, starting from 30–40 phr when DOA is the only plasticizer. There is no standard DOA share in a blend with a primary.
In a 2025 study of paste-resin films plasticized with DOA alone, the glass transition fell from −32.3 °C at 30 phr to −67.5 °C at 70 phr, and 50 phr gave a brittleness temperature of −62 °C. Lab films are not cable, so confirm the level on extruded insulation with the cold-bend test (IEC 60811-504) or the cold-impact test (IEC 60811-506).
The cold test the cable has to pass is set either by the customer’s installation temperature or by a low-temperature compound type such as TI 4 or TI 5 in EN 50363-3.
In a blend, a 2026 cable-compound study used 25 phr of DOA with 25 phr of DOTP or of TOTM as the other half. The cold test sets the lower end of the DOA level, and heat ageing sets the upper end.
Temperature Class Limits
Formulate a DOA compound for the 70 °C class, because DOA is more volatile than DOP or DINP.
Within the 70 °C class, DOA’s volatility shows in air-oven ageing and the loss-of-mass test (IEC 60811-409). IS 5831 runs both on general-purpose insulation for 7 days at 80 °C.
Other Ingredients
Resin K-Value
Use suspension PVC resin of K-67 to K-70, the range for cable compounds, with K-70 for the low-temperature DOA recipe.
Heat Stabilizer
Use a calcium-zinc stabilizer with a polyol or epoxidized-ester co-stabilizer.
For any cable sold into the EU, use no lead stabilizer. REACH has barred PVC articles containing 0.1% or more lead by weight since 29 November 2024.
Antioxidant
Add one only if the compound fails heat ageing without it, at 0.5–1.0 phr, the level the compounding guide’s heat-resistant cable recipe uses.
Fillers
Hold calcium carbonate to 0–10 phr, the general-purpose insulation level, or leave filler out, as the low-temperature DOA recipe does. The grade of calcium carbonate can change volume resistivity significantly, so qualify any new grade on insulation resistance.
Flame Retardants
Add antimony trioxide first when the cable’s fire specification requires more flame resistance than the base compound has. Alumina trihydrate and zinc borate are the other inorganic options. A phosphate plasticizer can also replace part of the ester plasticizer, at some cost to heat and light stability.
Impact Modifiers at Low Temperature
Published claims conflict on whether CPE helps or hurts the cold performance of a plasticized cable compound. Get the cold performance from the DOA level, and prove any CPE addition on your own cold-impact test.
Lubricants and Processing Aids
Use 1–3 phr of lubricant, either metallic stearates or ester waxes, and no processing aid.