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PMP and Formic Acid: Chemical Resistance

Polymethylpentene (TPX)

Rating

Concentration20 °C50 °CRemark
3 %AB
50 %AB
98-100 %AC

Material comparison at 20 °C

Formic Acid: Material comparison at 20 °CPMP: A (highlighted); Aluminium: A; ECTFE/ETFE: A; FEP: A; HDPE: A; LDPE: A.Aluminium: AECTFE/ETFE: AFEP: AHDPE: ALDPE: APMP: APMPPP: APTFE: APVC Flexible: APVDF: ASS 304: ASS 316: AEPDM: CPolycarbonate: CPolystyrene: CPolysulfone: CPVC Rigid: CSAN: CViton (FPM): 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

PMP shows excellent resistance to Formic Acid across all 3 tested concentrations (3 %, 50 %, 98-100 %) at 20 °C, making it a reliable choice for storage, transfer, and handling applications involving this chemical at any of the tested strengths. However, at 50 °C the resistance rating drops, indicating that temperature must be factored into the design. For heated applications, additional testing under actual service conditions is strongly recommended.

Application context

Formic Acid is commonly encountered in water treatment and chemical processing. PMP (Polymethylpentene (TPX)) is a thermoplastic typically used for tanks, piping, containers and liners. Because Formic Acid is classified as corrosive, the choice of containment material is especially critical to prevent leaks, equipment damage, and safety hazards.

Practical recommendation

PMP can be used with confidence for Formic 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. At elevated temperatures (50 °C), some reduction in resistance occurs, so periodic inspection is advisable for heated applications. Always verify performance under actual operating conditions before committing to a design.

Did you know?

The ratings shown here apply to pure Formic Acid in contact with the base thermoplastic. In real-world applications, additives, pigments, and fillers in the material can shift resistance in either direction.

Materials rated A or B at 20 °C

Based on the row for 98-100 %, 20 °C.

Thermoplastics
HDPE A, PP A, LDPE A, PVC Flexible A
Fluoropolymers
PTFE A, PVDF A, FEP A, ECTFE/ETFE A
Metals
SS 316 A, SS 304 A, Aluminium A

About PMP

Polymethylpentene (TPX) is a transparent polyolefin used for labware. It resists many acids and alkalis, while aromatic and chlorinated solvents and strong oxidisers attack it.

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.