DOTP

What Is DOTP?

DOTP — the full name is dioctyl terephthalate, also known as di(2-ethylhexyl) terephthalate or bis(2-ethylhexyl) terephthalate, CAS 6422-86-2 — is a general-purpose non-phthalate plasticizer built from purified terephthalic acid (PTA) and 2-ethylhexanol. It is a transparent, colorless to pale-yellow oily liquid with a density of 0.981–0.986 g/cm3, a boiling point of about 400 ℃ at 0.8 kPa, and a flash point of 205–210 ℃. It is insoluble in water but fully miscible with common organic solvents. Because its molecular structure contains no ortho-phthalate ester group, DOTP complies with the EU REACH regulation and is a mainstream replacement for traditional phthalate plasticizers such as DOP (DEHP).

DOTP vs DOP: Why the Industry Is Switching

The two molecules are structural isomers: DOP is esterified from phthalic anhydride, DOTP from terephthalic acid. That single shift of the acid group changes the performance envelope in ways compounders care about:

• Regulatory status: DOP/DEHP is a restricted phthalate under EU REACH and multiple consumer-product regulations; DOTP is a non-phthalate terephthalate and is widely accepted for sensitive applications including medical devices and children’s products, subject to local rules.
• Heat resistance: DOTP-plasticized PVC retains flexibility up to about 70 ℃ continuous service — roughly 10 ℃ better than DOP compounds — which matters for wire insulation rated 70 ℃ and above.
• Volatility and migration: DOTP is larger and more linear, so it volatilizes and migrates less. Products keep their flexibility longer, and fogging in automotive interiors is reduced.
• Cold flexibility and electrical properties: DOTP delivers equal or better low-temperature softness and excellent electrical insulation, making it a favorite for cable compounds.
• Viscosity behavior: DOTP is slightly more viscous than DOP, which plastisol formulators compensate for with small recipe adjustments.

Main Applications

PVC Cable Compounds and Wire Insulation

The largest single use of DOTP is soft PVC for wire and cable. Its combination of 70 ℃ heat rating, high volume resistivity, low volatility and non-phthalate status matches exactly what building-wire, automotive-harness and appliance-cable standards demand. Typical loading is 30–60 phr depending on flexibility target and filler level.

Artificial Leather and Coated Fabrics

Calendered and coated PVC for furniture upholstery, footwear, automotive trim and tarpaulins benefits from DOTP’s low migration and clean toxicity profile — increasingly a purchasing requirement for export-oriented fabricators.

Films and Sheets

Flexible films for packaging, stationery, shower curtains and industrial membranes use DOTP where low volatility and odor stability are required. Its low fogging also suits automotive interior films.

Medical Devices and New Energy Vehicles

Blood bags, tubing, mats and other soft PVC medical devices, plus interior and battery-component materials for electric vehicles, are high-end fields where the absence of restricted phthalates is mandatory and DOTP is the plasticizer of choice.

Other Applications

DOTP also plasticizes synthetic rubbers such as nitrile rubber, softens paper, and serves in coatings, inks and precision-instrument lubricant formulations.

Production Routes and Quality Control

DOTP is produced by esterifying purified terephthalic acid with 2-ethylhexanol under acid catalysis, followed by neutralization, degassing and polishing filtration. Fiber-grade PTA and 99.5%+ 2-EH feedstocks determine the final color and volatility of the product. Each EastChem batch is tested for ester content (99.5% minimum typical), acid value, water content, color (Pt-Co) and volume resistivity, and ships with a batch-specific COA.

Handling and Storage

DOTP is low-toxicity and non-corrosive, requiring no special hazard class for transport in most jurisdictions. Store in tightly closed drums or tanks in a dry, ventilated area; keep away from strong oxidizers. Under proper storage its shelf life is typically 24 months. Standard packaging is 200 kg galvanized or blue steel drums and 1000 kg IBC totes; flexitank and ISO-tank shipment for bulk users.

DOTP in Plastisols, Slush Molding and Dip Coating

Beyond dry blending, DOTP is the plasticizer of choice for plastisol processes — PVC paste systems for automotive sealants, underbody coatings, dip-molded gloves and slush-molded instrument skins. In these applications the plasticizer must flux the resin at controlled temperature without premature gelation during storage. DOTP’s moderate solvating power gives plastisols excellent shelf stability (low viscosity drift over weeks), while its low volatility keeps emission levels down during oven gelling at 160–200 ℃. Formulators switching from DOP typically observe a slightly higher initial paste viscosity, which is compensated by 1–3 phr of a viscosity depressant or a small dose of a faster-solvating co-plasticizer.

Formulation Guidance: Dosage vs Hardness

As a starting frame for soft PVC design: around 25–35 phr DOTP yields rigid-flexible compounds (Shore A 85–95); 40–55 phr covers the general flexible zone (Shore A 70–85) typical of cable jackets and footwear; 60–80 phr produces very soft compounds (Shore A 50–65) for soft-touch overmolding and coated fabrics. Exact hardness depends on K-value of the resin, filler loading and the co-plasticizer package — EastChem supports customers with starting formulations and comparative trials.

Regulatory and Market Context

Regulatory pressure on ortho-phthalates has converted DOTP into the default general-purpose plasticizer in many regions: it is not listed as an SVHC under EU REACH, supports phthalate-free marketing claims, and passes the low-migration expectations of toy, medical and automotive interior standards. Global capacity has expanded accordingly, and quality differentiation now comes from color stability, volume resistivity and consistency — parameters EastChem controls batch by batch. Buyers integrating DOTP into export products should still verify the specific migration limits of the destination market for their application class.

Compatibility and Blending

DOTP is compatible with PVC and most common co-plasticizers: epoxidized soybean oil (also a stabilizer), DOA for extra cold flexibility, chlorinated paraffins as secondary plasticizers, and polymeric polyesters for migration-critical parts. It dissolves standard stabilizer packages (Ca/Zn, Ba/Zn, lead-free systems) and pigments without color development — a direct consequence of its saturated terephthalate structure and low acidity. In nitrile rubber and other polar elastomers it acts as a non-extracting softener compatible with sulfur and peroxide cures.

What Plasticizer Buyers Should Verify Before Ordering

Four checks separate a trouble-free DOTP supply from a compounding headache. First, acid value (typically below 0.05 mg KOH/g): residual acid attacks PVC dehydrochlorination, discoloring compound and shortening heat stability. Second, volume resistivity (above 1 x 10^11 Ω·cm for cable grades): the single best predictor of insulation performance. Third, water content below 0.05%: moisture causes porosity in plastisol gelling and electrical faults in cable compounds. Fourth, color and color stability after heat aging — pale initial color that darkens after 100 ℃/24 h storage signals impurities that will eventually show in white and pastel products. A supplier who reports all four on every COA is doing real quality work.

Fogging, Emissions and Interior Air Quality

Automotive interior standards limit windshield fogging and volatile organic emissions. DOTP’s low vapor pressure makes it one of the lowest-fogging general-purpose plasticizers — a major reason vehicle makers specified it early during the phthalate transition. Compounders targeting automotive trim validate with gravimetric fog tests (DIN 75201-type) and chamber emission tests; using DOTP from a consistent producer removes the plasticizer as a variable in those audits.

Working with EastChem on DOTP Programs

Practical supply programs for plasticizer buyers usually combine three elements. A standing quarterly volume with agreed pricing bands covers base demand; spot allocations absorb seasonal peaks in cable and footwear production; and sample-first qualification for each new compound line protects against surprises. EastChem supports all three: fresh inventory in depth from a 19-year manufacturing base across three subsidiaries, batch data with every shipment, and technical correspondence that answers formulation questions the same working day. For buyers consolidating containers, DOTP pairs naturally with the feedstock 2-ethylhexanol, the cold-flexibility co-plasticizer DOA, and glycol products — one quality system, one document set, one logistics chain.

How to Choose a DOTP Supplier

When comparing suppliers, look beyond the price per ton: insist on per-batch COA with acid value and volume resistivity, verify REACH documentation for EU-bound cargo, and confirm packaging integrity for ocean freight. Dongying EastChem is a 19-year chemical manufacturer with three subsidiaries, supplying DOTP with complete documentation, stable batch-to-batch color, and consolidated shipment with feedstock 2-ethylhexanol and cold-flexibility co-plasticizer DOA. Minimum order is one 20′ container; samples dispatch in about 2 days; payment by T/T or L/C.

Contact for quotations and samples:
Fiona Wang
WeChat/Phone: +86 183 5460 9228 · WhatsApp: +86 183 5460 9228
Email: fiona@dyeastchem.com