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Sodium Hydroxide (Caustic Soda) Chemical Resistance

Resistance ratings for 24 plastics, elastomers and metals at 20 °C and 50 °C. Listed at 6 concentrations, because the rating depends on it.

At a glance

Based on the row for 60 %, 20 °C.

Rated A, very good resistance
PTFE, HDPE, PP, EPDM, SS 316, SS 304, LDPE, Nylon (PA), Polystyrene, Polysulfone, PMP (11)
Rated B, good resistance
NBR (1)
Rated C, limited resistance
Viton (FPM), Acetal (POM) (2)
Rated D, not resistant
PVDF, Aluminium, Polycarbonate, PETG (4)
No data in the source
PVC Rigid, FEP, ECTFE/ETFE, Silicone, PVC Flexible, SAN
Rated lower at 50 °C than at 20 °C
Viton (FPM) (C → D), NBR (B → C), SS 316 (A → C), SS 304 (A → C)
Rating changes with concentration (20 °C)
Viton (FPM): A (1 %), D (concentrated); NBR: A (1 %), C (50 %); SS 316: A (1 %), B (concentrated); SS 304: A (1 %), B (concentrated); Acetal (POM): A (1 %), C (60 %); Polycarbonate: C (1 %), D (30 %); Polystyrene: A (30 %), B (1 %); PETG: C (1 %), D (30 %)

Based on the row for 60 %, 20 °C.

Rating profile by material family

Sodium Hydroxide (Caustic Soda): Rating profile by material familyThermoplastics: 7 A, 1 C, 2 D, 3 no data. Fluoropolymers: 1 A, 1 D, 2 no data. Elastomers: 1 A, 1 B, 1 C, 1 no data. Metals: 2 A, 1 D.Thermoplastics (13)Thermoplastics: 7 × A, very good resistance (HDPE, LDPE, PP, PMP, Polystyrene, Nylon (PA), Polysulfone)A 7Thermoplastics: 1 × C, limited resistance (Acetal (POM))Thermoplastics: 2 × D, not resistant (Polycarbonate, PETG)D 2Thermoplastics: 3 × no data (PVC Rigid, PVC Flexible, SAN)– 3Fluoropolymers (4)Fluoropolymers: 1 × A, very good resistance (PTFE)A 1Fluoropolymers: 1 × D, not resistant (PVDF)D 1Fluoropolymers: 2 × no data (FEP, ECTFE/ETFE)– 2Elastomers (4)Elastomers: 1 × A, very good resistance (EPDM)A 1Elastomers: 1 × B, good resistance (NBR)B 1Elastomers: 1 × C, limited resistance (Viton (FPM))C 1Elastomers: 1 × no data (Silicone)– 1Metals (3)Metals: 2 × A, very good resistance (SS 316, SS 304)A 2Metals: 1 × D, not resistant (Aluminium)D 1
A very good resistanceB good resistanceC limited resistanceD not resistantno data
Number of materials in each family with each rating at 20 °C.

Effect of temperature, 20 °C to 50 °C

Sodium Hydroxide (Caustic Soda): Effect of temperature, 20 °C to 50 °CViton (FPM) C → D; NBR B → C; SS 316 A → C; SS 304 A → C.ABCDViton (FPM): C at 20 °C, D at 50 °CViton (FPM)NBR: B at 20 °C, C at 50 °CNBRSS 316: A at 20 °C, C at 50 °CSS 316SS 304: A at 20 °C, C at 50 °CSS 304
20 °C50 °C
Materials whose rating differs between 20 °C and 50 °C. Materials not shown keep their rating or have no 50 °C value.

Substance

CAS number
1310-73-2
Formula
NaHO
Hazard symbols in the source
C (corrosive) (pre-GHS European symbols; check the current safety data sheet)
Concentrations listed
1 %; 30 %; 45 %; 50 %; 60 %; concentrated
Also listed as
Sodium hydroxide solution
Name in the source (German)
Natriumhydroxid

Rating by concentration

Sodium Hydroxide (Caustic Soda): Rating by concentrationHDPE: 1 % A, 30 % A, 45 % A, 50 % A, 60 % A, concentrated A. LDPE: 1 % A, 30 % A, 45 % A, 50 % A, 60 % A, concentrated A. PP: 1 % A, 30 % A, 45 % A, 50 % A, 60 % A, concentrated A. PVC Rigid: 1 % A, 30 % A→C, 45 % A→C, 50 % A→B, 60 % –, concentrated –. PVC Flexible: 1 % –, 30 % A→C, 45 % A→C, 50 % –, 60 % –, concentrated –. PMP: 1 % A, 30 % A, 45 % A, 50 % A, 60 % A, concentrated –. Polystyrene: 1 % B, 30 % A, 45 % A, 50 % B, 60 % A, concentrated –. SAN: 1 % –, 30 % –, 45 % A, 50 % –, 60 % –, concentrated –. Polycarbonate: 1 % C→D, 30 % D, 45 % D, 50 % D, 60 % D, concentrated D. PETG: 1 % C*, 30 % D, 45 % D, 50 % D, 60 % D, concentrated D. Acetal (POM): 1 % A, 30 % A→C, 45 % A→C, 50 % A→C, 60 % C*, concentrated C*. Nylon (PA): 1 % A, 30 % A, 45 % A, 50 % A, 60 % A, concentrated A→C. Polysulfone: 1 % A, 30 % A, 45 % A, 50 % A, 60 % A, concentrated –. PTFE: 1 % A, 30 % A, 45 % A, 50 % A, 60 % A, concentrated A. FEP: 1 % A, 30 % A, 45 % –, 50 % A, 60 % –, concentrated –. PVDF: 1 % D, 30 % D, 45 % D, 50 % D, 60 % D, concentrated D. ECTFE/ETFE: 1 % A, 30 % –, 45 % –, 50 % A, 60 % –, concentrated –. EPDM: 1 % A, 30 % A, 45 % A, 50 % A, 60 % A, concentrated A. Viton (FPM): 1 % A, 30 % C*, 45 % B→D, 50 % C→D, 60 % C→D, concentrated D. NBR: 1 % A→C, 30 % B→C, 45 % B→C, 50 % C, 60 % B→C, concentrated C→D. SS 316: 1 % A, 30 % A→C, 45 % A→C, 50 % A→C, 60 % A→C, concentrated B*. SS 304: 1 % A, 30 % A→C, 45 % A→C, 50 % A→C, 60 % A→C, concentrated B*. Aluminium: 1 % D*, 30 % D, 45 % D, 50 % D, 60 % D, concentrated D.1 %30 %45 %50 %60 %concen…THERMOPLASTICSHDPEHDPE, 1 %: A at 20 °C, A at 50 °CAHDPE, 30 %: A at 20 °C, A at 50 °CAHDPE, 45 %: A at 20 °C, A at 50 °CAHDPE, 50 %: A at 20 °C, A at 50 °CAHDPE, 60 %: A at 20 °C, A at 50 °CAHDPE, concentrated: A at 20 °C, A at 50 °CALDPELDPE, 1 %: A at 20 °C, A at 50 °CALDPE, 30 %: A at 20 °C, A at 50 °CALDPE, 45 %: A at 20 °C, A at 50 °CALDPE, 50 %: A at 20 °C, A at 50 °CALDPE, 60 %: A at 20 °C, A at 50 °CALDPE, concentrated: A at 20 °C, A at 50 °CAPPPP, 1 %: A at 20 °C, A at 50 °CAPP, 30 %: A at 20 °C, A at 50 °CAPP, 45 %: A at 20 °C, A at 50 °CAPP, 50 %: A at 20 °C, A at 50 °CAPP, 60 %: A at 20 °C, A at 50 °CAPP, concentrated: A at 20 °C, A at 50 °CAPVC RigidPVC Rigid, 1 %: A at 20 °C, A at 50 °CAPVC Rigid, 30 %: A at 20 °C, C at 50 °CA→CPVC Rigid, 45 %: A at 20 °C, C at 50 °CA→CPVC Rigid, 50 %: A at 20 °C, B at 50 °CA→BPVC Rigid, 60 %: no data–PVC Rigid, concentrated: no data–PVC FlexiblePVC Flexible, 1 %: no data–PVC Flexible, 30 %: A at 20 °C, C at 50 °CA→CPVC Flexible, 45 %: A at 20 °C, C at 50 °CA→CPVC Flexible, 50 %: no data–PVC Flexible, 60 %: no data–PVC Flexible, concentrated: no data–PMPPMP, 1 %: A at 20 °C, A at 50 °CAPMP, 30 %: A at 20 °CAPMP, 45 %: A at 20 °CAPMP, 50 %: A at 20 °C, A at 50 °CAPMP, 60 %: A at 20 °CAPMP, concentrated: no data–PolystyrenePolystyrene, 1 %: B at 20 °C, B at 50 °CBPolystyrene, 30 %: A at 20 °CAPolystyrene, 45 %: A at 20 °C, A at 50 °CAPolystyrene, 50 %: B at 20 °C, B at 50 °CBPolystyrene, 60 %: A at 20 °CAPolystyrene, concentrated: no data–SANSAN, 1 %: no data–SAN, 30 %: no data–SAN, 45 %: A at 20 °C, A at 50 °CASAN, 50 %: no data–SAN, 60 %: no data–SAN, concentrated: no data–PolycarbonatePolycarbonate, 1 %: C at 20 °C, D at 50 °CC→DPolycarbonate, 30 %: D at 20 °C, D at 50 °CDPolycarbonate, 45 %: D at 20 °C, D at 50 °CDPolycarbonate, 50 %: D at 20 °C, D at 50 °CDPolycarbonate, 60 %: D at 20 °C, D at 50 °CDPolycarbonate, concentrated: D at 20 °C, D at 50 °CDPETGPETG, 1 %: C at 20 °C (estimate)C*PETG, 30 %: D at 20 °C, D at 50 °CDPETG, 45 %: D at 20 °C, D at 50 °CDPETG, 50 %: D at 20 °C, D at 50 °CDPETG, 60 %: D at 20 °C, D at 50 °CDPETG, concentrated: D at 20 °C, D at 50 °CDAcetal (POM)Acetal (POM), 1 %: A at 20 °C, A at 50 °CAAcetal (POM), 30 %: A at 20 °C, C at 50 °CA→CAcetal (POM), 45 %: A at 20 °C, C at 50 °CA→CAcetal (POM), 50 %: A at 20 °C, C at 50 °CA→CAcetal (POM), 60 %: C at 20 °C (estimate)C*Acetal (POM), concentrated: C at 20 °C (estimate)C*Nylon (PA)Nylon (PA), 1 %: A at 20 °CANylon (PA), 30 %: A at 20 °CANylon (PA), 45 %: A at 20 °CANylon (PA), 50 %: A at 20 °CANylon (PA), 60 %: A at 20 °CANylon (PA), concentrated: A at 20 °C, C at 50 °CA→CPolysulfonePolysulfone, 1 %: A at 20 °C, A at 50 °CAPolysulfone, 30 %: A at 20 °CAPolysulfone, 45 %: A at 20 °CAPolysulfone, 50 %: A at 20 °C, A at 50 °CAPolysulfone, 60 %: A at 20 °CAPolysulfone, concentrated: no data–FLUOROPOLYMERSPTFEPTFE, 1 %: A at 20 °C, A at 50 °CAPTFE, 30 %: A at 20 °C, A at 50 °CAPTFE, 45 %: A at 20 °C, A at 50 °CAPTFE, 50 %: A at 20 °C, A at 50 °CAPTFE, 60 %: A at 20 °C, A at 50 °CAPTFE, concentrated: A at 20 °C, A at 50 °CAFEPFEP, 1 %: A at 20 °C, A at 50 °CAFEP, 30 %: A at 20 °C, A at 50 °CAFEP, 45 %: no data–FEP, 50 %: A at 20 °C, A at 50 °CAFEP, 60 %: no data–FEP, concentrated: no data–PVDFPVDF, 1 %: D at 20 °C, D at 50 °CDPVDF, 30 %: D at 20 °C, D at 50 °CDPVDF, 45 %: D at 20 °C, D at 50 °CDPVDF, 50 %: D at 20 °C, D at 50 °CDPVDF, 60 %: D at 20 °C, D at 50 °CDPVDF, concentrated: D at 20 °C, D at 50 °CDECTFE/ETFEECTFE/ETFE, 1 %: A at 20 °C, A at 50 °CAECTFE/ETFE, 30 %: no data–ECTFE/ETFE, 45 %: no data–ECTFE/ETFE, 50 %: A at 20 °C, A at 50 °CAECTFE/ETFE, 60 %: no data–ECTFE/ETFE, concentrated: no data–ELASTOMERSEPDMEPDM, 1 %: A at 20 °CAEPDM, 30 %: A at 20 °CAEPDM, 45 %: A at 20 °CAEPDM, 50 %: A at 20 °CAEPDM, 60 %: A at 20 °CAEPDM, concentrated: A at 20 °CAViton (FPM)Viton (FPM), 1 %: A at 20 °C, A at 50 °CAViton (FPM), 30 %: C at 20 °C (estimate)C*Viton (FPM), 45 %: B at 20 °C, D at 50 °CB→DViton (FPM), 50 %: C at 20 °C, D at 50 °CC→DViton (FPM), 60 %: C at 20 °C, D at 50 °CC→DViton (FPM), concentrated: D at 20 °C, D at 50 °CDNBRNBR, 1 %: A at 20 °C, C at 50 °CA→CNBR, 30 %: B at 20 °C, C at 50 °CB→CNBR, 45 %: B at 20 °C, C at 50 °CB→CNBR, 50 %: C at 20 °C, C at 50 °CCNBR, 60 %: B at 20 °C, C at 50 °CB→CNBR, concentrated: C at 20 °C, D at 50 °CC→DMETALSSS 316SS 316, 1 %: A at 20 °C, A at 50 °CASS 316, 30 %: A at 20 °C, C at 50 °CA→CSS 316, 45 %: A at 20 °C, C at 50 °CA→CSS 316, 50 %: A at 20 °C, C at 50 °CA→CSS 316, 60 %: A at 20 °C, C at 50 °CA→CSS 316, concentrated: B at 20 °C (estimate)B*SS 304SS 304, 1 %: A at 20 °C, A at 50 °CASS 304, 30 %: A at 20 °C, C at 50 °CA→CSS 304, 45 %: A at 20 °C, C at 50 °CA→CSS 304, 50 %: A at 20 °C, C at 50 °CA→CSS 304, 60 %: A at 20 °C, C at 50 °CA→CSS 304, concentrated: B at 20 °C (estimate)B*AluminiumAluminium, 1 %: D at 20 °C (estimate)D*Aluminium, 30 %: D at 20 °C, D at 50 °CDAluminium, 45 %: D at 20 °C, D at 50 °CDAluminium, 50 %: D at 20 °C, D at 50 °CDAluminium, 60 %: D at 20 °C, D at 50 °CDAluminium, concentrated: D at 20 °C, D at 50 °CD
A very good resistanceB good resistanceC limited resistanceD not resistantno data
Each cell shows the rating at 20 °C. Where the rating at 50 °C differs, it follows the arrow. * marks an estimate in the source.
Show as a table
Material1 %30 %45 %50 %60 %concentrated
Thermoplastics
HDPEAAAAAA
LDPEAAAAAA
PPAAAAAA
PVC RigidAAAA––
PVC Flexible–AA–––
PMPAAAAA–
PolystyreneBAABA–
SAN––A–––
PolycarbonateCDDDDD
PETGC*DDDDD
Acetal (POM)AAAAC*C*
Nylon (PA)AAAAAA
PolysulfoneAAAAA–
Fluoropolymers
PTFEAAAAAA
FEPAA–A––
PVDFDDDDDD
ECTFE/ETFEA––A––
Elastomers
EPDMAAAAAA
Viton (FPM)AC*BCCD
NBRABBCBC
Silicone––––––
Metals
SS 316AAAAAB*
SS 304AAAAAB*
AluminiumD*DDDDD

* estimated rating, given in the source without a temperature

Resistance table: Sodium Hydroxide (Caustic Soda), 1 %

Material20 °C50 °CRemark
Thermoplastics
HDPEAA
LDPEAA
PPAA
PVC RigidAA
PMPAA
PolystyreneBB
PolycarbonateCD
PETGC*–
Acetal (POM)AA
Nylon (PA)A–
PolysulfoneAA
Fluoropolymers
PTFEAA
FEPAA
PVDFDDcorrected, see below
ECTFE/ETFEAA
Elastomers
EPDMA–
Viton (FPM)AA
NBRAC
Metals
SS 316AA
SS 304AA
AluminiumD*–

* estimated rating, given in the source without a temperature

Not rated in the source, so not in the table: PVC Flexible, SAN, Silicone

Resistance table: Sodium Hydroxide (Caustic Soda), 30 %

Material20 °C50 °CRemark
Thermoplastics
HDPEAA
LDPEAA
PPAA
PVC RigidAC
PVC FlexibleAC
PMPA–
PolystyreneA–
PolycarbonateDD
PETGDD
Acetal (POM)AC
Nylon (PA)A–
PolysulfoneA–
Fluoropolymers
PTFEAA
FEPAA
PVDFDDcorrected, see below
Elastomers
EPDMA–
Viton (FPM)C*–
NBRBC
Metals
SS 316AC
SS 304AC
AluminiumDD

* estimated rating, given in the source without a temperature

Not rated in the source, so not in the table: SAN, ECTFE/ETFE, Silicone

Resistance table: Sodium Hydroxide (Caustic Soda), 45 %

Material20 °C50 °CRemark
Thermoplastics
HDPEAA
LDPEAA
PPAA
PVC RigidAC
PVC FlexibleAC
PMPA–
PolystyreneAA
SANAA
PolycarbonateDD
PETGDD
Acetal (POM)AC
Nylon (PA)A–
PolysulfoneA–
Fluoropolymers
PTFEAA
PVDFDDcorrected, see below
Elastomers
EPDMA–
Viton (FPM)BD
NBRBC
Metals
SS 316AC
SS 304AC
AluminiumDD

Not rated in the source, so not in the table: FEP, ECTFE/ETFE, Silicone

Resistance table: Sodium Hydroxide (Caustic Soda), 50 %

Material20 °C50 °CRemark
Thermoplastics
HDPEAA
LDPEAA
PPAA
PVC RigidAB
PMPAA
PolystyreneBB
SAN–C
PolycarbonateDD
PETGDD
Acetal (POM)AC
Nylon (PA)A–
PolysulfoneAA
Fluoropolymers
PTFEAA
FEPAA
PVDFDDcorrected, see below
ECTFE/ETFEAA
Elastomers
EPDMA–
Viton (FPM)CD
NBRCC
Metals
SS 316AC
SS 304AC
AluminiumDD

Not rated in the source, so not in the table: PVC Flexible, Silicone

Resistance table: Sodium Hydroxide (Caustic Soda), 60 %

Material20 °C50 °CRemark
Thermoplastics
HDPEAA
LDPEAA
PPAA
PMPA–
PolystyreneA–
PolycarbonateDD
PETGDD
Acetal (POM)C*–
Nylon (PA)A–
PolysulfoneA–
Fluoropolymers
PTFEAA
PVDFDDcorrected, see below
Elastomers
EPDMA–
Viton (FPM)CD
NBRBC
Metals
SS 316AC
SS 304AC
AluminiumDD

* estimated rating, given in the source without a temperature

Not rated in the source, so not in the table: PVC Rigid, PVC Flexible, SAN, FEP, ECTFE/ETFE, Silicone

Resistance table: Sodium Hydroxide (Caustic Soda), concentrated

Material20 °C50 °CRemark
Thermoplastics
HDPEAA
LDPEAA
PPAA
PolycarbonateDD
PETGDD
Acetal (POM)C*–
Nylon (PA)AC
Fluoropolymers
PTFEAA
PVDFDDcorrected, see below
Elastomers
EPDMA–
Viton (FPM)DD
NBRCD
Metals
SS 316B*–
SS 304B*–
AluminiumDD

* estimated rating, given in the source without a temperature

Not rated in the source, so not in the table: PVC Rigid, PVC Flexible, PMP, Polystyrene, SAN, Polysulfone, FEP, ECTFE/ETFE, Silicone

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.

Corrected and disputed values

Source values use the scale 1 (very good) to 4 (not resistant); 1 = A, 4 = D.

Frequently Asked Questions

Which materials resist Sodium Hydroxide (Caustic Soda) at high concentrations?

The materials with an A rating (resistant) for Sodium Hydroxide (Caustic Soda) at 20 °C are: PTFE, HDPE, PP, EPDM, SS 316, SS 304, LDPE, Nylon (PA). These can generally be used in direct contact.

Which materials should be avoided with Sodium Hydroxide (Caustic Soda)?

Materials rated D (not resistant) for Sodium Hydroxide (Caustic Soda) are: PVDF, Aluminium, Polycarbonate, PETG. These should not be used in contact with Sodium Hydroxide (Caustic Soda).

Does temperature affect chemical resistance to Sodium Hydroxide (Caustic Soda)?

Yes. 4 of 12 tested materials show a worse rating at 50 °C than at 20 °C for Sodium Hydroxide (Caustic Soda). Materials affected include: Viton (FPM), NBR, SS 316, SS 304.

Is PTFE safe for Sodium Hydroxide (Caustic Soda)?

PTFE is rated A for Sodium Hydroxide (Caustic Soda) at 20 °C. A rating of A means resistant, B means limited resistance, C means partly resistant, and D means not resistant.

Does concentration affect chemical resistance to Sodium Hydroxide (Caustic Soda)?

Yes. Sodium Hydroxide (Caustic Soda) is tested at 6 concentrations (1 %, 30 %, 45 %, 50 %, 60 %, concentrated). Some materials change their rating depending on the concentration.

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.

Chemicals with a similar resistance profile

Same 20 °C rating on the share of materials shown.

Potassium Hydroxide 78 %Aluminum Nitrate 72 %Copper Sulfate (Copper Vitriol) 72 %Glycolic Acid 71 %Potassium Cyanide 71 %Ammonium Carbonate 71 %