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PTFE and Phosphoric Acid: Chemical Resistance

Polytetrafluoroethylene

Rating

Concentration20 °C50 °CRemark
1-5 %AA
20 %AA
30 %AA
85 %AA

Material comparison at 20 °C

Phosphoric Acid: Material comparison at 20 °CPTFE: A (highlighted); ECTFE/ETFE: A; FEP: A; Viton (FPM): A; HDPE: A; LDPE: A.ECTFE/ETFE: AFEP: AViton (FPM): AHDPE: ALDPE: APolycarbonate: APMP: APP: APolystyrene: APolysulfone: APTFE: APTFEPVC Rigid: APVC Flexible: APVDF: ASAN: ASS 316: ASS 304: BEPDM: CAluminium: DNBR: DNylon (PA): DAcetal (POM): DPETG: –Silicone: –
A very good resistanceB good resistanceC limited resistanceD not resistantno data
Each bar is one material. Taller bars indicate better resistance. The highlighted bar is the current material.

Resistance overview

PTFE shows excellent resistance to Phosphoric Acid across all 4 tested concentrations (1-5 %, 20 %, 30 %, 85 %) at 20 °C, making it a reliable choice for storage, transfer, and handling applications involving this chemical at any of the tested strengths. The rating remains stable between 20 °C and 50 °C, which means this material can also handle moderately elevated process temperatures without additional risk.

Application context

Phosphoric Acid is commonly encountered in surface cleaning and chemical processing. PTFE (Polytetrafluoroethylene) is a fluoropolymer typically used for seals, gaskets, valve seats and lined equipment. Because Phosphoric Acid is classified as corrosive, the choice of containment material is especially critical to prevent leaks, equipment damage, and safety hazards.

Practical recommendation

PTFE can be used with confidence for Phosphoric Acid containment and handling. The A rating indicates that the material shows no significant change in weight, dimensions, or mechanical properties after prolonged contact under test conditions. This holds true at both 20 °C and 50 °C, giving a good safety margin for typical process environments.

Did you know?

When choosing between fluoropolymers for Phosphoric Acid service, engineers consider not just the resistance rating but also factors such as permeation rate, creep resistance, and weldability.

Materials rated A or B at 20 °C

Based on the row for 85 %, 20 °C.

Thermoplastics
HDPE A, PP A, PVC Rigid A, LDPE A, Polycarbonate A, PVC Flexible A, Polystyrene A, Polysulfone A, PMP A, SAN A
Fluoropolymers
PVDF A, FEP A, ECTFE/ETFE A
Elastomers
Viton (FPM) A
Metals
SS 316 A, SS 304 B

About PTFE

PTFE is resistant to almost every chemical in this list. The known exceptions are molten alkali metals, elemental fluorine and some fluorinating agents at elevated temperature.

Rating scale

A rating marked * is an estimate in the source, not a test result. An estimate is given as one value without a temperature.

About this data

The ratings come from the chemical resistance list published by Bürkle GmbH, which compiled them from raw-material manufacturers’ data. They describe laboratory tests on the raw material at 20 °C and 50 °C.

A finished part also sees pressure, mechanical stress, welds and mixtures that a laboratory test does not. Treat the rating as a first filter and test under your own conditions before relying on it.