Application scope for SABIC (Ibn Rushd) purified terephthalic acid covers six commercial conversion routes: bottle-grade PET resin, polyester filament and staple fiber, PBT engineering thermoplastics, aromatic polyester polyols for rigid polyurethane, dioctyl terephthalate plasticizer, and saturated polyester powder coating resins. The sections below specify compliance anchors, formulation addition rates, production process parameters, and finished article categories for each route.

Bottle-Grade PET Starts from a Low-Aldehyde PTA Paste Feed

Bottle-grade PET conversion of SABIC (Ibn Rushd) PTA is operated as a direct esterification-polycondensation sequence. Compliance for food-contact use is anchored to FDA 21 CFR 177.1630, EU Regulation (EU) No 10/2011 overall migration limit of 10 mg/dm², and REACH Regulation (EC) No 1907/2006. The paste feed is prepared at 70–75 wt% PTA in monoethylene glycol, corresponding to a molar excess of EG to PTA of 1.12:1 to 1.20:1; the final PET repeat unit contains 86.5 wt% esterified terephthalate. Continuous esterification is controlled at 250–270 °C and 0.1–0.3 MPa in a two-vessel cascade, with esterification degree exceeding 96%; antimony trioxide catalyst at 180–260 ppm Sb and phosphoric acid stabilizer at 50–80 ppm P are injected before polycondensation. Melt polycondensation proceeds at 275–290 °C below 1 mbar absolute pressure in horizontal disc-ring reactors, reaching intrinsic viscosity 0.60–0.65 dL/g. Solid-state polymerization in a continuous crystallizer-preheater reactor at 200–220 °C under nitrogen raises intrinsic viscosity to 0.82–0.88 dL/g for bottle preform injection. Residual 4-carboxybenzaldehyde above 25 mg/kg cannot be fully compensated by solid-state polymerization and raises preform acetaldehyde levels, requiring higher acetaldehyde scavenger dosage in downstream conversion. Finished product types include carbonated soft drink, still water, hot-fill juice, edible oil, and pharmaceutical syrup bottles.

Why Does Melt Viscosity Stability in Polyester Filament Spinning Depend on 4-CBA and p-Toluic Acid Control?

In continuous filament lines, SABIC (Ibn Rushd) PTA is fed as a paste with monoethylene glycol at a molar ratio of 1.13:1 to 1.18:1, with titanium dioxide delustrant added at 0.3–2.0 wt% depending on semi-dull or full-dull grade; high-shear inline mixers operating at 3,000–5,000 rpm disperse TiO₂ before esterification. Compliance for apparel and home textile grades is evaluated against OEKO-TEX Standard 100 Annex 4 limits for extractable antimony and ZDHC MRSL v3.1 for spin finish and polymerization wastewater control. Melt preparation is carried out at 280–295 °C through a continuous polymerization line with a residence time from esterification to spinning of 3–5 h; 4-carboxybenzaldehyde must be maintained below 25 mg/kg because residual aldehyde groups act as chain terminators and raise carboxyl end-group concentration, which correlates with hydrolytic degradation at spinneret temperatures above 285 °C. For partially oriented yarn, filtration through 20 µm sintered metal packs precedes spinnerets with capillary diameter 0.20–0.28 mm, and take-up speed is set at 3,000–6,000 m/min to control orientation-induced crystallinity. Drawn textured yarn is produced with draw ratios of 1.5–1.7 and texturing disc surface temperatures of 180–210 °C. Staple fiber lines draw at 80–100 °C with a crimp frequency of 8–12 crimps per 25 mm and cut lengths of 38–51 mm. Terminal product categories cover woven and knitted apparel, sports outerwear, automotive interior fabrics, upholstery, carpets, nonwoven geotextile, and high-bulk fiberfill.

PBT Resin Formulation and Injection Moulding Behaviour

Esterification of SABIC (Ibn Rushd) PTA with 1,4-butanediol to produce polybutylene terephthalate is governed by ISO 1628-1 for intrinsic viscosity determination using 0.005 g/mL in phenol/1,2-dichlorobenzene at 25 °C, UL 94 V-0/V-2 flame ratings for molded specimens after 48 h conditioning at 23 °C/50% RH, IEC 60695-2-12 glow-wire ignition temperature for electrical component housings, and Directive 2011/65/EU RoHS restrictions. The feed molar ratio of PTA to BDO is set at 1:1.30 to 1:1.50 to compensate for tetrahydrofuran formation during esterification; titanium-based catalyst is charged at 50–150 ppm Ti relative to PTA. Pre-esterification at 220–240 °C under atmospheric pressure is followed by polycondensation at 250–270 °C and absolute pressure below 100 Pa in a wiped-film or thin-film finishing reactor. Glass-fiber reinforced grades incorporate 20–30 wt% chopped glass fiber downstream, and compounds are injection molded at melt temperatures 240–260 °C, mold temperatures 40–80 °C, and clamp force 1,200–3,500 kN. Terminal product types include automotive connectors, relay bases, windshield wiper brackets, sensor housings, brush holders, and insulation parts for low-voltage switchgear.

When PTA Replaces Phthalic Anhydride in Aromatic Polyester Polyols

Aromatic polyester polyol synthesis with SABIC (Ibn Rushd) PTA is specified for rigid polyisocyanurate boardstock where low flame spread and char integrity are design requirements. Compliance is evaluated under EN 13165:2012+A2:2016 for factory-made rigid cellular PIR boards, ASTM E84 for surface burning characteristics, and REACH Regulation (EC) No 1907/2006 for substance registration. Formulation of the polyol component uses 20–50 wt% PTA, 50–70 wt% diethylene glycol, and 5–15 wt% phthalic anhydride or recycled aromatic stream as co-diacid; the finished polyol is controlled to hydroxyl value 300–450 mg KOH/g, acid value below 2.0 mg KOH/g, and viscosity 2,000–6,000 mPa·s at 25 °C. Esterification is run at 200–230 °C under nitrogen with continuous water removal, then vacuum below 50 mbar until acid value falls below 2.0 mg KOH/g. Residual acidity above 5 mg KOH/g in the polyol consumes polymeric MDI at the foam metering line, generating carbon dioxide and reducing foam density; the vacuum stage is therefore extended to the specified acid value before blending. In rigid foam processing, the polyol is blended with 8–15 parts per 100 parts polyol n-pentane or cyclo/isopentane and reacted with polymeric MDI at isocyanate index 250–350 for PIR boards. Terminal finished product types include closed-cell PIR insulation boards of 100–200 mm thickness, pipe insulation segments, pre-insulated duct panels, and spray-applied rigid polyurethane insulation.

In flexible PVC compounding, dioctyl terephthalate derived from SABIC (Ibn Rushd) PTA is introduced as a non-phthalate plasticizer with production compliance anchored to EU Regulation (EU) No 10/2011 specific migration limit of 60 mg/kg, EN 71-3 migration limits for toy formulations, and REACH Regulation (EC) No 1907/2006 registration. The molar feed ratio of PTA to 2-ethylhexanol is set at 1:2.10 to 1:2.50, with tetrabutyl titanate catalyst added at 0.05–0.15 wt% of PTA; finished DOTP must meet ester content 99.5 wt% minimum, acid value 0.07 mg KOH/g maximum, and specific gravity 0.984–0.986 at 20 °C. Esterification proceeds at 210–230 °C with continuous water removal via azeotropic distillation, followed by vacuum stripping at 150–180 °C and 5–20 mbar to remove unreacted 2-ethylhexanol to below 100 mg/kg. The resulting DOTP is filtered through 5 µm cartridges before storage. During dry blending, the plasticizer is absorbed at 30–60 phr depending on Shore hardness target; high-speed mixers operate at 800–1,200 rpm to 110–120 °C. Terminal product categories include insulation and sheathing for low-voltage wire and cable, vinyl flooring, automotive interior panels, medical tubing, and toys.

Saturated polyester resin for thermoset powder coating formulated with SABIC (Ibn Rushd) PTA is typically based on a co-acid system of 40–60 wt% PTA, 30–40 wt% neopentyl glycol, and 1–5 wt% trimethylolpropane as branching agent. Compliance testing of the applied coating follows ASTM D3451-24 for testing polymer powders and ISO 8130-6 for determination of gel time at 180 °C; architectural powder coatings are additionally evaluated under Qualicoat specifications for weathered aluminum. The resin is synthesized at 230–250 °C under nitrogen, with vacuum below 50 mbar applied in the final stage to reach acid value 30–80 mg KOH/g and glass transition temperature 55–70 °C. Finished resin flake is ground with a classifier to particle size D50 35–45 µm and cured at 180–200 °C for 15–20 min with 7–10 wt% triglycidyl isocyanurate or 3–5 wt% β-hydroxyalkylamide. Terminal finished product types include architectural aluminum curtain wall powder coating, appliance casings, automotive underbody and wheel rim coatings, and MDF furniture finishes.