Technical Report HYT-504

®

Hytrel

®

Thermoplastic Polyester Elastomer

Fluid and chemical resistance guide

Start with DuPont Engineering Polymers

® DuPont registered trademark

Fluid and chemical resistance guide The data tabulated in this report document the effects of a broad variety of chemicals, solvents, oils and hydraulic fluids on HYTREL® thermoplastic polyester elastomer1. A summary guide to the chemical resistance of HYTREL® is presented in Table I. As a general rule, the resistance of HYTREL® to fluids and chemicals increases as the hardness of the polymer increases (see Table II). Stress-strain and volume increase data for 40D, 55D and 72D grades of HYTREL® following immersion in a variety of fluids are listed in Tables III through V. Resistance to various classes of fluids

HYTREL® vs, some other thermoplastics

HYTREL® has excellent resistance to non-polar materials such as oils and hydraulic fluids, even at elevated temperatures. If necessary, resistance to hot oils can be further enhanced by heat-stabilisation. The superior hot oil ageing resistance of heat-stabilised types such as HYTREL® 5555HS2 is described in other literature (see bulletin HYT-105).

In general, HYTREL® is resistant to the same classes of chemicals and fluids, as are polyurethanes, both ester and ether based. However, HYTREL® has better high temperature properties than the polyurethanes, and can be used satisfactorily at higher temperatures in the same fluids. For example, after exposure at 150° C for 7 days in ASTM Oil No. 1, 55D HYTREL® swells only about 2%, and retains 60% of its original tensile strength and 90% of its original elongation; polyurethanes of equivalent hardness degrade in less than a week at the same conditions.

HYTREL® is resistant to most polar fluids – such as acids, bases, amines and glycols at room temperature. However, its resistance to polar fluids is poor at temperatures of 70° C or above. HYTREL® should not be used in service that requires continuous exposure to these fluids at elevated temperatures. Resistance of HYTREL® to moist environments is good at room temperature. Hydrolytic stability can be improved at elevated temperature by incorporating HYTREL® 10MS as a stabiliser. Recommendations covering the use of HYTREL® 10MS3 are presented in bulletin HYT-114.

HYTREL® thermoplastic polyester elastomers do not contain an extractable plasticizer, as do flexible vinyls, certain grades of nylon and many rubber compounds. Many fluids and chemicals will extract the plasticizer from these materials, causing a significant increase in stiffness (modulus) and volume shrinkage. For example, a plasticised nylon of approximately 63D hardness undergoes a two-fold increase in modulus and shrinks about 10% when exposed to ASTM Oil No. 1 for 7 days at 120° C. HYT HYTREL® shows no change in modulus and swells approximately 0,3% under the same exposure conditions.

1, 2, 3 These superscript numbers refer to the proprietary materials listed on page 9.

1

Table I Chemical resistance guide for HYTREL®

The data tabulated below summarise the effects of a broad variety of fluids on HYTREL® thermoplastic polyester elastomers. As a general rule the resistance of HYTREL® to fluids and chemicals increases as the polymer hardness increases. Unless otherwise noted the ratings shown in the table apply to all hardness grades. Rating Key: A – B– C– T– X–

Fluid has little or no effect Fluid has minor to moderate effect Fluid has severe effect No data – likely to have minor effect No data – likely to have severe effect

Ratings are at 23° C unless otherwise specified. Concentrations of aqueous solutions are saturated, except where noted. We emphasise that the data contained herein should be used as a guide only. The tabulation is based primarily on laboratory tests but does not take into account all variables that can be encountered in actual use. Therefore it is advisable to test the material under actual service conditions before specification. If this is not practical, tests should be devised that simulate service conditions as closely as possible. Chemical

Rating

Chemical

Rating

Acetic Acid, 20% Acetic Acid, 30% Acetic Acid, Glacial Acetic Acid, Glacial (38°C) Acetic Anhydride

A A A B T

Boric Acid Solutions Bromine, Anhydrous Liquid Butane Butyl Acetate Butyl Acetate

A X A B (40, 55D) A (72D)

Acetone Acetylene Aluminium Chloride Solutions Aluminium Sulphate Solutions Ammonium Chloride Solutions

B A T T A

Calcium Chloride Solutions Calcium Hydroxide Solutions Calcium Hypochlorite, 5% Carbon Bisulfide Carbon Bisulfide

A T A B (40, 55D) A (72D)

Ammonium Hydroxide Solutions Ammonium Sulphate Solutions Ammonium Sulphate Solutions Amyl Acetate Amyl Alcohol

T B (40, 55D) A (72D) B A

Carbon Dioxide Carbon Monoxide Carbon Tetrachloride Carbon Tetrachloride Carbon Tetrachloride

A A C (40D) B (55D) A (72D)

Aniline ASTM Oil No. 1 (150°C) ASTM Oil No. 3 (150°C) ASTM Reference Fuel A (70°C) ASTM Reference Fuel B (70°C)

C A A A A

Castor Oil Castor Oil Chlorine Gas, Dry Chlorine Gas, Wet Chloroacetic Acid

B (40, 55D) A (72D) X X X

ASTM Reference Fuel C ASTM Reference Fuel C (70°C) ASTM Reference Fuel C (70°C) Asphalt Atrazine

A B (40, 55D) A (72D) T A

Chlorobenzene Chloroform Chloroform Chlorosulfonic Acid Citric Acid Solutions

X C (40, 55D) B (72D) C A

Barium Hydroxide Solutions Beer Benzene Benzene Borax Solutions

T A B (40, 55D) A (72D) A

Copper Chloride Solutions Copper Sulphate Solutions Cottonseed Oil Cyclohexane Dibutyl Phthalate

A A A A A

2

Table I Chemical resistance guide for HYTREL® (continued) Chemical

Rating

Chemical

Rating

Diethyl Sebacate Dioctyl Phthalate DUAL5 Epichlorohydrin Ethyl Acetate

A A A X B (40, 55D)

Mercury Methyl Alcohol Methyl Ethyl Ketone Methyl Ethyl Ketone Methylene Chloride

A A B (40, 55D) A (72D) C

Ethyl Acetate Ethyl Alcohol Ethyl Chloride Ethyl Chloride Ethylene Dichloride

A (72D) A C (40, 55D) B (72D) C (40, 55D)

Mineral Oil Naphtha Naphthalene Naphthalene Nitric Acid, 10%

A A B (40, 55D) A (72D) B

Ethylene Dichloride Ethylene Glycol Ethylene Oxide Ferric Chloride Solutions FIuosilicic Acid

B (72D) A A T T

Nitric Acid, 30% Nitric Acid, 60% Nitric Acid, 70% Nitric Acid, Red Fuming Nitrobenzen

C C C C C

Formaldehyde, 40% Formic Acid FREON 116 FREON 12 FREON 113 (55°C)

B B A A A

Oleic Acid Oleum, 20-25% Palmitic Acid Perchloroethylene Perchloroethylene

A C A C (40, 55D) B (72D)

FREON 114 Glue Glycerine n-Hexane Hydrazine

A A A A C

Petrol Petrol Phenol Pickling Solution (20% Nitric Acid, 4% HF) Pickling Solution (17% Nitric Acid, 4% HF)

B (55D) A (72D) C X X

Hydrochloric Acid, 20% Hydrochloric Acid, 37% Hydrocyanic Acid Hydrofluoric Acid, 48% Hydrofluoric Acid, 75%

B C T X X

Potassium Dichromate Solutions Potassium Hydroxide Solutions PYDRAUL 31210 Pyridine SAE 10 Oil

T A A X A

Hydrofluoric Acid, Anhydrous Hydrogen Hydrogen Sulphide Isooctane Isopropyl Alcohol

X A A A A

Sea Water Silicone Grease SKYDROL 500B11 Soap Solutions Sodium Chloride Solutions

A A A A A

JP-4 Jet Fuel Kerosene Lacquer Solvents Lacquer Solvents Lactic Acid

A T B (40, 55D) A (72D) T

Sodium Dichromate, 20% Sodium Hydroxide, 20% Sodium Hydroxide, 46,5% Sodium Hypochlorite, 5% Soybean Oil

T A B A T

Linseed Oil Lubricating Oils Magnesium Chloride Solutions Magnesium Hydroxide Solutions Mercuric Chloride Solutions

T A T T T

Stannous Chloride, 15% Steam (100°C) Steam (110°C) Stearic Acid Styrene

T B C T X

3

Table I Chemical resistance guide for HYTREL® (continued) Chemical

Rating

Chemical

Rating

Sulphur, Molten Sulphur Dioxide, Liquid Sulphur Dioxide, Gas Sulphuric Acid, up to 50% Sulphuric Acid, above 50%

T T T A C

Trichloroethylene Triethanolamine Trisodium Phosphate Solution Tung Oil Water (70°C)

B (72D) C A T A

Sulphuric Acid, Fuming (20% Oleum) Sulphurous Acid Tannic Acid, 10% Tartaric Acid Tetrahydrofuran

C B A T B (40, 55D)

Water (100°C) Xylene Xylene Zinc Chloride Solutions

B B (40, 55D) A (72D) A

Tetrahydrofuran Toluene Toluene TREFLAN12 Trichloroethylene

A (72D) B (40, 55D) A (72D) B C (40, 55D)

Table II Effect of hardness on chemical and fluid resistance of HYTREL® Immersion

Volume increase, %

Fluid

Time days

Temperature °C

Oils and Hydraulic Fluids ASTM Oil No. 1 ASTM Oil No. 3 Ethylene Glycol PYDRAUL 31210 SKYDROL 500B11

7 7 7 7 7

100 100 23 100 100

2 23