KLJ Plasticizers Kanatol 8080 Dioctyl Terephthalate (DOTP)

Wire Insulation Compounds Operating Inside IEC 60332-1 Flame and ISO 6722 Thermal Envelopes

Kanatol 8080 (dioctyl terephthalate, DOTP) is added to suspension-grade PVC with K-value 65–68 at 55–70 PHR for insulation and 50–65 PHR for sheathing in 600/1000 V building wire and automotive primary cable constructions. The lower vapour pressure of DOTP relative to DEHP or DINP becomes critical in dry-cure crosshead extrusion where melt temperatures at the die exit are held between 150 °C and 170 °C; under these conditions volatile plasticiser loss in an unvented single-screw extruder with L/D 30:1 can shift Shore A hardness by 2–4 points if a lower-molecular-weight ortho-phthalate is substituted. Plasticiser volatility is screened by ASTM D1203 Method A activated-carbon loss over 24 h at 70 °C, with DOTP-containing compounds retaining lower weight loss than DEHP at equal PHR. Compound production for these insulation grades typically runs on a co-rotating twin-screw extruder at L/D 44:1 with barrel zone temperatures from 120 °C to 160 °C, followed by strand pelletising. The dry blend is prepared in a turbo mixer with a drop temperature of 125 °C and cooling to 45 °C before pelletising. Finished primary wire must demonstrate tensile strength at break of at least 12.5 MPa and elongation at break of at least 150% when tested according to IEC 60502-1 Table 17 type PVC/A on tensile specimens cut to ISO 527-2 type 1B; automotive thin-wall grades are additionally checked against ISO 6722-1 thermal overload resistance at 150 °C for 3000 h, and building wires are subject to flame propagation testing under IEC 60332-1-2 with a 60 s vertical flame application. Regulatory documentation for these constructions routinely cites REACH Regulation (EC) No 1907/2006 Annex XVII Entry 51, which restricts DEHP, DBP, BBP, and DIBP, and Entry 52, which restricts DINP, DIDP, and DNOP in certain toys and childcare articles; DOTP is not listed in either entry. EU RoHS 2011/65/EU applies to electrical and electronic equipment and does not prohibit DOTP. The terminal article range includes single-core building wire sizes from 0.5 mm² to 6.0 mm², flexible cords under UL 62, automotive ISO primary wire, appliance lead wire, and internal wiring harnesses for white goods. The critical processing constraint is not initial fusion but longer-term thermal ageing: compounds held above 180 °C for residence times beyond 90 s during crosshead extrusion may initiate dehydrochlorination in stagnation zones, so Ca-Zn or organic phosphite stabiliser packages are adjusted upward when DOTP addition exceeds 65 PHR. No universal extrusion profile can be declared without converter-side validation against the final cable standard.

Automotive instrument panel skins and door panel coverstocks are converted from PVC plastisol in which Kanatol 8080 is charged at 70–90 PHR per 100 PHR of paste resin, with viscosity reduced by aliphatic diluents from 10 PHR to 20 PHR before vacuum deaeration at 5–10 kPa. The plastisol is cast onto release paper or directly into a slush-mold nickel shell heated to 220–250 °C; gelation dwell times of 40–90 s produce skins with Shore A hardness 60–75 and surface grain depth determined by post-cooling embossing. Low-VOC and fogging requirements are evaluated under VDA 278 thermodesorption at 90 °C for VOC and 120 °C for SVOC, and fogging condensate is tested by DIN 75201-B or ISO 6452. For a two-layer interior trim laminate, the compact skin layer containing DOTP at 70 PHR is fused to a polypropylene foam backing at 120–150 °C using a hot-plate press at 0.4–0.6 MPa; delamination strength after ageing is checked according to DIN 53357-A. Unlike DEHP-based plastisols, DOTP-containing skins can maintain fogging condensate below the 2.0 mg limit commonly filed in OEM material specifications, but the gelation oven profile must be raised by 5–10 °C when switching from a high-ortho-phthalate formula to avoid under-gelled resin particles that appear as surface pitting. End products produced through this route include instrument panel skins, door insert covers, console armrest skins, and interior coated fabrics for headliners. Process control focuses on plastisol viscosity stability over 48 h at 25 °C and deaeration efficiency, because incomplete air release is the primary cause of pinhole defects on grained surfaces; converter data from three-shift automotive lines indicate that viscosity rise above 1500 mPa·s after 24 h is often correlated with knife-over-roll coating streaks, though exact viscosity limits are typically defined in closed OEM material specifications.

What Happens to Plasticizer Migration When DOTP Meets Blood-Contact PVC?

Blood storage containers and extracorporeal tubing produced from medical-grade PVC require plasticiser systems that survive steam autoclave cycles at 121 °C for 30 min without generating tacky surfaces or leaching low-molecular-weight species into stored plasma. Kanatol 8080 is let down into PVC of K-value 70–75 at 60–80 PHR for film and 50–70 PHR for tubing; the resulting Shore A hardness falls in the 70–85 range. Compatibility and migration under simulated contact are assessed under ISO 3826:2013 for plastics collapsible containers for blood and blood components, with extractables profiling performed according to ISO 10993-1 and cytotoxic response screened by ISO 10993-5. Film conversion uses a counter-rotating twin-screw extruder with L/D 24:1 at melt temperatures from 140 °C to 160 °C, followed by flat-die film casting at thickness 0.35–0.50 mm; bags are then sealed by high-frequency welding at 27.12 MHz and sterilised. Unlike DEHP, which has documented extraction into blood and interaction with red blood cell membranes, DOTP shows reduced migration under extraction but must still be evaluated for each blood bag formulation because the plasticizer migrates into lipids over storage periods exceeding 21 days; no universally applicable extractables profile can be assumed across all blood bag formats and lipid contents. Regulatory submissions for medical devices reference ISO 10993 biological evaluation and, where US FDA clearance is being assembled, the compounder may reference 21 CFR 178.3740 for plasticizer inventory; final article clearance under the applicable medical device route remains a converter-specific demonstration. Converters are also required to verify compliance with REACH Regulation (EC) No 1907/2006 Annex XVII Entry 51 and EU Medical Device Regulation (EU) 2017/745 general safety and performance requirements. Terminal product types include red blood cell storage bags, platelet containers, anaesthesia breathing circuit tubing, and peristaltic pump tubes. The critical boundary is not PVC fusion but migration kinetics: plasticizer exudation increases when the compound is exposed to ethylene oxide sterilization gas at residual moisture above 60% RH, because hydrolytic cleavage of the ester is favoured at high humidity; incoming resin and filler moisture should be dried to below 0.05% before compounding to avoid surface haze after steam sterilisation.

In resilient flooring, Kanatol 8080 is incorporated as the primary plasticizer in compacted PVC wear layers where dimensional stability after exposure to 80 °C for 6 h is tested according to ISO 23999, and thermal expansion under 80 °C is controlled for interlocking LVT products. Addition ratios are lower than in cable or medical film: wear layers are typically formulated with 30–50 PHR DOTP on 100 PHR suspension PVC, while printed decorative layers and backing layers use 40–60 PHR to retain calender pick-up without excessive surface tack. The production sequence begins in a Banbury internal mixer at 140–160 °C, continues onto a two-roll mill, and then passes through a four-roll inverted-L calender at 160–180 °C to form a sheet of 0.5–2.0 mm. The calendered sheet is laminated to a PVC core layer in a multi-daylight hot press at 150–180 °C and 20–40 bar, then annealed at 70 °C for 24 h before UV-cured polyurethane topcoat application at 10–20 g/m². Compliance for residential and commercial floor coverings is documented under EN ISO 10582 and EN ISO 26986 for wear layer thickness and indentation resistance; indoor emissions are screened by ISO 16000-6 after 28 days in chamber testing. DOTP’s lower weight loss during calendering reduces roll plate-out compared with DEHP at equivalent PHR, but the compound’s melt viscosity is slightly higher, so calendering bowl temperatures should not drop below 160 °C or the sheet will exhibit marginal bank rotation and surface roughness. End products include luxury vinyl tile, stone plastic composite flooring with resilient LVT top layers, commercial resilient sheet flooring, and wall base profiles. The main processing boundary is the embossing temperature window: when DOTP is used at 60 PHR in the wear layer, post-embossing recovery is less than 1.5% only if the surface is cooled below 40 °C before leaving the embossing nip; otherwise grain depth relaxation occurs within 24 h.

When a Toy Molder Switches from DINP to DOTP Without Adjusting Gelation Temperatures

Rotomoulded vinyl toys and childcare articles are a regulatory-sensitive downstream for Kanatol 8080 because the substance is not covered by REACH Annex XVII Entry 51 restrictions on DEHP, DBP, BBP, and DIBP, while DINP remains restricted under Entry 52 when the toy can be placed in the mouth. In PVC plastisol for soft doll bodies and squeeze toys, addition levels range from 50 PHR to 80 PHR per 100 PHR paste resin, depending on target Shore A hardness 55–70. Processing uses open-mould rotational casting or slush casting; the metal mould is heated to 190–220 °C, filled with plastisol, rotated on two axes at 6–12 rpm, and cooled to 40 °C before demoulding. The documented processing conflict is gelation: DOTP-containing plastisol generally requires a mould-surface temperature 5–10 °C higher than an equivalent DINP formula to achieve complete fusion. When this adjustment is ignored, the inner surface remains under-gelled and organic compounds can migrate during EN 71-10 sample preparation and EN 71-11 analysis, causing a fail under EN 71-9 category-specific migration limits; additionally, under-cured parts exhibit plasticizer exudation and surface tack quantified as blocking force above 1.0 N after 24 h under 0.5 kPa. Compliance documentation should cite EN 71-1 mechanical requirements, EN 71-3 migration of certain elements, and EN 71-9/10/11 organic chemical compounds where applicable. The operational boundary for molder conversion is that DOTP provides slightly lower plasticising efficiency than DINP; adding 5–10 PHR higher DOTP is often necessary to maintain identical Shore A hardness, but this can push total plasticizer above 85 PHR, at which point embossing definition and rotational mould release degrade unless a silicone release agent is applied. Terminal product types include soft vinyl doll heads, squeeze-activated bath toys, ball-shaped rattles, and vinyl book covers for young children. Final articles must be verified under the notified-body test regime specified by the Toy Safety Directive.

Because DOTP exhibits lower vapour pressure than ortho-phthalate plasticizers at 180 °C, synthetic leather foam layers made from Kanatol 8080 are used for shoe uppers and furniture upholstery where emissions and long-term flex crack resistance are controlled. The plastisol for the foamed interlayer contains 60–85 PHR DOTP on 100 PHR PVC paste resin, 3–5 PHR azodicarbonamide blowing agent, and a kicker such as zinc oxide at 1–2 PHR; the compact top coat is formulated at 50–70 PHR DOTP to maintain abrasion resistance. Coating is performed by release-paper transfer on a knife-over-roll line running at 12–45 m/min; gelation tunnels are set to 140–190 °C in six zones, with the final zone at 210–220 °C triggering foaming and collapse to the final thickness before lamination to polyester knitted scrim. After cooling to 30 °C, the release paper is stripped and the surface is embossed on a heated grain roller at 120–150 °C. Compliance for upholstery uses ISO 105-C06 colour fastness to domestic and commercial laundering, ISO 12947-2 abrasion resistance by Martindale at 50,000 cycles, and ISO 16000-6 indoor emission testing; footwear material is additionally checked for flexing endurance under ISO 5402-2 after 50,000 cycles dry and 10,000 cycles wet. End product types include breathable microporous synthetic leather for athletic footwear, coated fabric for handbags, contract-grade upholstery, and automotive seating topcoats where OEM VOC requirements are met through low-VOC plasticizer selection. The main equipment boundary is the final foaming zone: if the web temperature exceeds 220 °C, excessive blowing agent decomposition creates cell coalescence and delamination at the fabric interface, while below 200 °C the foam layer lacks uniform cell structure and fails flex endurance; DOTP viscosity stability in the coating trough over an 8 h shift must be monitored with a Brookfield RV spindle 6 at 20 rpm to maintain knife-over-roll coat weight within ±3%.