Mitsui Chemicals PTA
- Product Name: Mitsui Chemicals PTA
- Factroy Site: Yinchuan, Ningxia, China
- Price Inquiry: sales8@ascent-chem.com
- Manufacturer: Ascent Petrochem Holdings Co., Limited
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- Mitsui Chemicals PTA is typically used in formulations when purity and particle size distribution and processing temperature and residence time must be controlled within specific ranges.
| HS Code | 158946 |
| Productname | Mitsui Chemicals PTA |
| Chemicalname | Purified Terephthalic Acid |
| Chemicalformula | C8H6O4 |
| Molecularweight | 166.13 g/mol |
| Casnumber | 100-21-0 |
| Appearance | White crystalline powder |
| Odor | Odorless |
| Purity | ≥99.9% |
| Meltingpoint | >300 °C (sublimes) |
| Density | 1.55 g/cm³ |
| Bulkdensity | 0.8–1.0 g/cm³ |
| Solubilityinwater | Practically insoluble |
| Moisturecontent | ≤0.1% |
| Acidvalue | 675–678 mg KOH/g |
| Ashcontent | ≤10 ppm |
| 4 Carboxybenzaldehyde | ≤25 ppm |
| P Toluicacid | ≤150 ppm |
| Particlesize | 100–200 µm |
| Color | White |
As an accredited Mitsui Chemicals PTA factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Mitsui Chemicals PTA is supplied in 1,000 kg jumbo bags or 25 kg bags, palletized and wrapped for industrial transport. |
| Container Loading (20′ FCL) | Mitsui Chemicals PTA loaded in 20′ FCL, about 20 MT per container, using palletized 25 kg bags or jumbo bags. |
| Shipping | Mitsui Chemicals PTA is transported as a non-hazardous solid in 25 kg bags, 1,000 kg jumbo bags, or bulk containers. Shipments require clean, dry, covered conditions to prevent moisture and contamination. Standard ocean containers, bulk vessels, and land transport are used; no special IMDG hazard class applies. |
| Storage | Store Mitsui Chemicals PTA in a cool, dry, well-ventilated place in tightly closed containers, away from ignition sources, strong oxidizers, and bases. Prevent dust generation and accumulation; use grounding and bonding during transfer. Store at ambient temperature, avoiding excessive heat. Keep separate from food and feed. Protect from moisture and direct sunlight. Follow local regulations and SDS recommendations. |
| Shelf Life | Mitsui Chemicals PTA has a recommended shelf life of 12 months when stored cool, dry, and well-ventilated in sealed containers. |
What Limits Acetaldehyde Generation in Bottle-Grade PET Solid-State Polymerization?
The bottle-grade PET solid-state polymerization line begins with high-purity purified terephthalic acid (PTA) supplied by Mitsui Chemicals loaded into a paste preparation vessel at a molar ratio PTA:EG of 1:1.15 to 1:1.25, with antimony trioxide added at 190–230 ppm Sb, cobalt acetate at 2–5 ppm Co for blue tint control, and phosphoric acid at 15–30 ppm P as thermal stabilizer. The upstream melt process runs continuous esterification at 260–285 °C under 0.1–0.3 MPa, then polycondensation at 275–290 °C under 0.1–1.0 kPa to a melt intrinsic viscosity of 0.55–0.63 dL/g measured per ASTM D4603-18; pelletized amorphous resin is crystallized at 140–160 °C before entering the SSP reactor at 210–220 °C for 10–18 h under nitrogen flow to reach 0.78–0.84 dL/g. Acetaldehyde generation is the dominant control variable: residual acetaldehyde in injected preforms is held below 3 ppm in resin to avoid off-taste, and the SSP step strips vinyl end groups and acetaldehyde through inert-gas sweep; PTA with 4-carboxybenzaldehyde below 25 mg/kg and p-toluic acid below 150 mg/kg is required because these monofunctional impurities cap chain growth and depress intrinsic viscosity build-up. Food-contact compliance is governed by FDA 21 CFR 177.1630 and EU Regulation 10/2011, with batch release testing against ASTM D4603-18 for intrinsic viscosity and headspace gas chromatography for acetaldehyde. Terminal product types produced from this resin include 28 mm PCO soft-drink preforms, 5-gallon water bottles, and monolayer rPET-containing containers processed on injection stretch-blow molding equipment.
Continuous direct esterification fiber-grade PET lines operating at 300–600 t/day use Mitsui Chemicals PTA and ethylene glycol in a paste molar ratio PTA:EG of 1:1.18 to 1:1.25, with delustering-grade titanium dioxide added at 0.30–0.50 wt% of the melt for semi-dull filaments, antimony trioxide catalyst at 250–300 ppm Sb, and phosphorous stabilizer at 20–50 ppm P. Esterification proceeds in calandria reactors at 260–275 °C under 0.15–0.30 MPa, followed by pre-polycondensation at 270–280 °C and final polycondensation at 280–290 °C under <1 mbar to an intrinsic viscosity of 0.62–0.68 dL/g per ASTM D4603-18. Spinning is conducted at 285–298 °C through spinnerets with 15–25 µm filtration media; winding speeds for partially oriented yarn range from 2,800 m/min to 4,500 m/min, and draw texturing operates at 600–900 m/min for 75 denier/36 filament to 300 denier/96 filament DTY. On industrial lines, titanium dioxide agglomerates above 20 µm are the predominant cause of spin pack pressure rise above 120 bar; therefore, high-shear dispersion and final filtration to 15 µm are maintained to limit filament breaks. Regulatory coverage includes REACH Regulation (EC) No 1907/2006 Annex XVII for monomer migration limits and Oeko-Tex Standard 100 limit values for textile-related chemical residues; melt quality is additionally checked by ISO 1133-1:2022 melt mass-flow rate testing for lot-to-lot variance. Downstream yarn and nonwoven outputs are POY, DTY, FDY, staple fiber for ring-spun yarns, and spunbond nonwoven filaments used in hygiene and geotextile applications.
Biaxially Oriented Polyester Film: Anti-Block Additive Distribution and Stretch Ratio Limits
In cast film extrusion for biaxial orientation, Mitsui Chemicals PTA is combined with ethylene glycol at a molar ratio PTA:EG of 1:1.10 to 1:1.20 before continuous polycondensation to an intrinsic viscosity of 0.60–0.65 dL/g, because lower viscosity improves draw uniformity while higher viscosity raises die pressure and reduces throughput. Spherical silica anti-block particles with median particle size 1.5–4.0 µm are metered at 0.05–0.30 wt% to control film slip and winding performance; excess silica raises haze above 5% and reduces clarity, while insufficient silica causes blocking on the mill roll. The molten polymer is filtered through 20–30 µm media and extruded at 275–285 °C onto a chill roll held at 25–30 °C, producing a cast sheet that is stretched sequentially at 3.0–3.5× in the machine direction at 85–100 °C and 3.5–4.0× in the transverse direction at 100–115 °C, then heat-set at 220–230 °C with 3–7% relaxation to control thermal shrinkage. Food-contact grades are tested under FDA 21 CFR 177.1630 and EU Regulation 10/2011, electrical-grade film under IEC 60674-3-2, and optical performance by ASTM D1003-13 for haze and ASTM D1894-14 for coefficient of friction. Finished film formats span from 12 µm lidding films and metallized barrier webs to 2.5–6 µm capacitor dielectric film and 125–250 µm photovoltaic backsheet outer layers.
When 1,4-Butanediol Is Directly Esterified with PTA for Quick-Crystallizing Engineering Resin
Direct esterification of Mitsui Chemicals PTA with 1,4-butanediol proceeds in batch or continuous lines at a molar ratio PTA:BDO of 1:1.30 to 1:1.50; the excess diol compensates for tetrahydrofuran formation during the esterification stage, which is run at 225–240 °C with nitrogen sparging and reflux splitting to remove water and THF. Tetrabutyl titanate is added at 40–150 ppm Ti as esterification and polycondensation catalyst, and triphenyl phosphite at 0.1–0.3 wt% is introduced as a heat stabilizer before vacuum polymerization at 245–255 °C under <0.5 mbar to an intrinsic viscosity of 0.85–1.15 dL/g per ASTM D4603-18. The resulting PBT pellets must be dried to <0.02% moisture before melt processing; injection molding uses barrel temperatures of 240–260 °C, melt temperature 250–270 °C, and mold temperature 60–100 °C. Residence time above 10 min at 260 °C causes intrinsic viscosity loss greater than 0.03 dL/g through hydrolytic chain scission, a processing boundary observed on hot-runner tooling where gate melt temperatures are kept below 265 °C. Mechanical property testing follows ISO 527-1/-2 for tensile properties, flammability is classified under UL 94 HB or UL 94 V-0 depending on additive package, and material designation follows ISO 7792-1. Molded components produced from this material include automotive sensor connectors, ECU housings, relay bobbins, brush holders for power tools, and low-moisture electrical switch components.
In sheet molding compound manufacture, Mitsui Chemicals PTA is introduced at 15–40 mol% of the acid component to reduce styrene volatility and raise heat distortion temperature of cured panels; the remaining acid component is maleic anhydride at 60–85 mol%, and propylene glycol is charged at 5–10% molar excess over total acid groups. The single-stage melt condensation runs at 200–220 °C with nitrogen sparging until the acid value reaches 18–28 mg KOH/g per ISO 2114, after which the resin is cut with styrene monomer at 32–38 wt% of final resin and inhibited with hydroquinone at 50–100 ppm. SMC/BMC compounding on production lines requires high-shear mixing of PTA-derived unsaturated polyester resin with magnesium oxide thickening agents, glass fiber at 20–30 wt%, and mineral fillers such as calcium carbonate at 40–60 wt%; the compound is compacted at 1.0–1.5 MPa on SMC machines and aged at 35–40 °C until molding viscosity reaches 50–100 million mPa·s. The low solubility of PTA in propylene glycol at the early stage of esterification demands particle size reduction below 20 µm or longer cook cycles; otherwise unreacted PTA crystals cause acid value drift and gelation during thickening. Compliance for molded components is specified under ASTM D1201-13 and ISO 14530-2, with fire-retarded grades tested to UL 94 V-0. Molded parts from this compound are used in automotive exterior panels, valve covers, electrical distribution boxes, building facade elements, and glass-fiber reinforced sanitaryware.
Powder Coating Resin Acid Value Drift When Neopentyl Glycol Sublimation Is Ignored
In powder coating polyester resin synthesis, Mitsui Chemicals PTA is used at 30–70 mol% of the acid component, with isophthalic acid and adipic acid balancing flexibility, and neopentyl glycol at 85–100 mol% of total diol to provide weathering resistance; trimethylolpropane is added at 0.5–2.0 wt% for branching and outdoor flow control. The melt condensation is run in two stages at 240–250 °C with vacuum below 5 kPa, and the acid value is monitored by ISO 2114 until the endpoint matches the selected crosslinker: 20–35 mg KOH/g for triglycidyl isocyanurate at 7–9 wt% or 30–50 mg KOH/g for β-hydroxyalkylamide at 5–8 wt%. Neopentyl glycol sublimation in the condenser system is a known source of acid value drift during the final vacuum stage; a packed column with glycol reflux to the reactor is used to keep the diol balance stable within ±2 mg KOH/g. Powder coating extrusion then blends the flaked resin with titanium dioxide at 20–30 wt%, flow agent at 0.8–1.5 wt%, and degassing agent at 0.3–0.6 wt% in a co-rotating twin-screw extruder with L/D ratio 40:1 and barrel temperature 90–120 °C; the extrudate is milled to D50 35–45 µm through an air classifier. Architectural powder coated aluminum is qualified under Qualicoat Class 1 and AAMA 2604-13, with coating evaluation by ASTM D3451-15. Qualified end articles fabricated from the cured powder coating include aluminum window profiles, architectural curtain wall panels, alloy wheel topcoats, and domestic appliance side panels.
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- Mitsui Chemicals PTA is manufactured under an ISO 9001 quality system and complies with relevant regulatory requirements.
- COA, SDS/MSDS, and related certificates are available upon request. For certificate requests or inquiries, contact: sales8@ascent-chem.com.
Purified terephthalic acid (PTA), CAS 100-21-0, is a crystalline aromatic dicarboxylic acid with the molecular formula C8H6O4 and a molecular weight of 166.13 g·mol−1. Mitsui Chemicals PTA is supplied as a dry powder for polyester polymerization; the real density is 1.51 g·cm−3 at 25 °C, water solubility is 0.0017 g/100 mL at 25 °C, and the acid dissociation constants are pKa1 3.51 and pKa2 4.82. The product is the primary dicarboxylic acid feedstock for polyethylene terephthalate (PET), polybutylene terephthalate (PBT), selected polyester polyols, and copolyester bottle resins. Publicly available product-specific model codes for Mitsui Chemicals PTA are limited; commercial differentiation is usually controlled through certificate-of-analysis limits, packaging configuration, and particle-size distribution rather than through widely published grade names.
What Distinguishes PTA from MTA, QTA, and PIA in Melt-State Condensation?
PTA is the 1,4-benzenedicarboxylic acid isomer, producing linear polyesters with high crystallinity and melt stability. Medium-purity terephthalic acid (MTA) and crude terephthalic acid (QTA) contain higher 4-carboxybenzaldehyde, p-toluic acid, and color-body concentrations; they are not interchangeable with polyester-grade PTA in high-intrinsic-viscosity bottle resin without additional purification. Purified isophthalic acid (PIA), the 1,3-benzenedicarboxylic acid isomer, is used as a comonomer at 1–3 wt% in bottle-grade PET to depress crystallization rate and improve stretch blow molding. Dimethyl terephthalate (DMT), the dimethyl ester of terephthalic acid, replaces PTA in transesterification-based polyester routes; DMT releases methanol during polycondensation, whereas PTA releases water. The direct esterification route using PTA is generally more cost-efficient for continuous PET plants and avoids methanol recovery, but it requires tighter particle-size and impurity management because PTA is a solid with limited solubility in ethylene glycol.
Production-scale PTA is obtained by liquid-phase air oxidation of p-xylene in acetic acid at 150–205 °C and 1.5–3.0 MPa using a homogeneous cobalt-manganese-bromine catalyst. The crude terephthalic acid is purified by water dissolution at 250–290 °C and hydrogenation over a fixed-bed palladium-carbon catalyst at 6.0–8.0 MPa, followed by crystallization, centrifugation, and drying. The hydrogenation step converts 4-carboxybenzaldehyde to p-toluic acid and saturates color-forming unsaturated species; final PTA retains trace amounts of p-toluic acid, ash, and water. The following table lists representative polyester-grade PTA certificate-of-analysis ranges. Producer-specific values for Mitsui Chemicals PTA may be set by contract and should be obtained from the supplier certificate.
| Parameter | Unit | Representative range | Method basis |
|---|---|---|---|
| 4-Carboxybenzaldehyde | mg/kg | ≤25 | HPLC after alkaline dissolution |
| p-Toluic acid | mg/kg | ≤150 | HPLC |
| Ash | mg/kg | ≤15 | ISO 3451-1:2019 combustion |
| Moisture | wt% | ≤0.5 | ASTM E203 Karl Fischer titration |
| Median particle size | µm | 100–150 | ISO 13320:2020 laser diffraction |
| Acid number | mg KOH/g | 675–677 | Titration against potassium hydroxide |
When 4-CBA and p-Toluic Acid Carryover Limit Intrinsic Viscosity Build
4-Carboxybenzaldehyde (4-CBA) is a monofunctional aldehyde impurity that acts as a chain limiter during PET polycondensation. At finisher temperatures of 275–290 °C and pressures below 2.0 mbar, 4-CBA can react with ethylene glycol but does not offer a second carboxylic acid site for step-growth extension. The resulting chain ends reduce the number-average molecular weight attainable at a given finisher residence time. Commercial polyester-grade PTA specifications therefore require 4-CBA ≤25 mg/kg and p-toluic acid ≤150 mg/kg. Published kinetic correlations between 4-CBA and PET intrinsic viscosity vary with antimony, titanium, or germanium catalyst selection, diethylene glycol suppression, melt temperature history, and finisher vacuum; a universal intrinsic-viscosity offset cannot be assigned without site-specific reactor data.
p-Toluic acid is the monomethyl-substituted aromatic acid generated from incomplete oxidation of p-xylene. Because it contains one carboxylic acid group and one methyl group, it also terminates chain extension when present. Its volatility is higher than that of PTA, which can lead to deposition in vacuum systems and glycol recovery columns. For continuous PET plants using ethylene glycol recycle, residual p-toluic acid can accumulate in recovered ethylene glycol and compete with virgin PTA for esterification sites; therefore, the recycled ethylene glycol is periodically purged or distilled to control p-toluic acid concentration. Published data for accumulation rates in Mitsui Chemicals PTA-specific supply chains are limited.
In continuous terephthalic acid-based PET processes, PTA is slurried with ethylene glycol at an ethylene glycol-to-terephthalic acid molar ratio of 1.1–1.5 and esterified at 260–270 °C under 0.3–0.5 MPa in a paste mixer or first esterification vessel. Esterification conversion is typically driven above 90% before high-vacuum polycondensation. Particle-size distribution of PTA directly affects slurry viscosity and unreacted acid carryover: median particle sizes larger than 150 µm can reduce dissolution rate and leave crystalline PTA in prepolymer filters; excessive fines below 45 µm increase dust formation but improve short-time mixing dispersion. Continuous PET plants therefore require a narrow particle-size distribution, with the span (D90−D10)/D50 commonly evaluated for consistent slurry feed.
Mitsui Chemicals PTA is used in bottle-grade PET, textile fiber, engineering thermoplastics, and polyester polyol formulations. Bottle-grade PET for carbonated soft drink preforms typically targets intrinsic viscosity 0.80–0.85 dL/g per ASTM D4603-18; the formulation includes ethylene glycol and 1–3 wt% purified isophthalic acid for crystallinity control. Solid-state polycondensation feed resin is dried to below 50 mg/kg moisture to prevent hydrolytic degradation. Fiber-grade PET for partially oriented yarn targets intrinsic viscosity 0.62–0.65 dL/g; for high-tenacity industrial yarn, higher intrinsic viscosity is obtained by solid-state advancement. Fiber melt lines typically use filtration at 20–40 µm absolute to remove agglomerates and undissolved acid residues, with elevated p-toluic acid or metal residues increasing filter pressure and spinning breaks.
PBT produced from PTA and 1,4-butanediol uses titanium-based catalysts such as tetrabutyl titanate; melt-mass flow rate is measured per ISO 1133-1:2022 at 250 °C under 2.16 kg load. Unsaturated polyester resins can incorporate PTA as a partial replacement for phthalic anhydride; because PTA has low solubility in styrene monomer, the cook requires staged addition and higher reaction temperatures to avoid unreacted acid sedimentation. For polyester polyols used in rigid polyurethane foam, PTA and diethylene glycol are condensed at 180–230 °C with organotin or zinc catalysts; acid number is lowered below 2 mg KOH/g for compatibility with isocyanate. PTA-based polyols have higher aromatic content than phthalic anhydride-based polyols, but published property comparisons depend on hydroxyl number and functionality.
Bulk Powder Handling and Combustible Dust Risk Boundaries
PTA powder forms combustible dust; site-specific samples should be characterized by ASTM E1226 for dust deflagration index KSt and ASTM E2019 for minimum ignition energy. Fine particles below 63 µm can have minimum ignition energy below 10 mJ, requiring conductive grounding in pneumatic transfer lines, baghouse filter elements, and FIBC filling and discharge stations. Hopper flow problems arise when the product contains high fines and moisture above 0.3 wt%; cohesive strength increases and the angle of repose can exceed 40°. Production-scale bulk handling systems therefore avoid continuous high-velocity dilute-phase conveying that generates fines and use dense-phase conveying at 3–6 bar g where possible. Rotary airlocks are inspected for blade clearance because attrition in a star valve is a common source of sub-45 µm dust generation. Silos and day bins in continuous PET plants are specified with mass-flow outlet geometry and vibratory discharge when moisture control during railcar unloading is required.
Flexible intermediate bulk containers used for PTA transfer should be selected for grounding compatibility: Type C FIBCs require connection to earth during filling and discharge, while Type D FIBCs dissipate charge through conductive fabric. The hazardous area classification of bag dump stations and silo top filters should reflect the site-specific dust explosibility data rather than a generic St class. Published dust explosion data for Mitsui Chemicals PTA are limited; test values depend on particle-size distribution, moisture content, and the presence of fines generated during pneumatic handling.
Merchant PTA producers are differentiated by certificate-of-analysis stability, trace-metal profile, particle-size distribution width, and impurity content under recycle conditions. Mitsui Chemicals PTA is not publicly distinguished by a branded model number; buyers typically specify polyester-grade PTA with the general limits above and evaluate batch-to-batch variability in moisture, 4-CBA, p-toluic acid, and Hunter b* reflectance. The following table summarizes route-level differences among common aromatic dicarboxylic feedstocks for polyester manufacture.
| Feedstock | Chemical form | Main process route | Typical polyester effect |
|---|---|---|---|
| PTA | 1,4-diacid, solid | Direct esterification with ethylene glycol; water byproduct | High crystallinity PET/PBT feedstock |
| MTA | 1,4-diacid with higher 4-CBA and p-toluic acid | Requires purification or low-grade resin use | Lower intrinsic viscosity and greater color risk |
| QTA | Crude oxidation solids | Not suitable for direct high-intrinsic-viscosity PET | Purification or non-polyester use |
| DMT | Dimethyl ester | Transesterification with ethylene glycol; methanol byproduct | Historical fiber PET route; higher monomer cost |
| PIA | 1,3-diacid | Copolymerization with PTA and ethylene glycol | Lower crystallinity, slower crystallization |
The product is intended for closed industrial polymerization processes; exposure controls should follow the safety data sheet for nuisance particulate and combustible dust. Reactive incompatibilities include strong oxidizing agents, reducing agents, and strong bases; exothermic decomposition can occur above 380 °C. Storage at relative humidity above 60% requires sealed hoppers or pre-drying because water absorption increases caking and downstream hydrolytic degradation. Food-contact use is not a property of PTA itself but of the finished PET packaging; finished PET can be assessed against FDA 21 CFR 177.1630 and the European Plastics Regulation 10/2011. REACH registration obligations apply at or above 1 tonne/year. Published data for Mitsui Chemicals PTA-specific emission factors and migration limits are limited to the supplier safety data sheet and regulatory dossier.
