O-ring material
Ethylene-Acrylic O-Rings
Ethylene-acrylic O-rings are the AEM seal, the family sold under the Vamac® trade name, chosen for hot automotive oils and greases where the seal must also start cold. The Parker® O-Ring Handbook rates the family from -40 C to 149 C with a shorter life to 163 C, and Conquest supplies ethylene-acrylic O-rings in AS568 and metric sizes as a distributor, quoted in the compound the print names.
- Family
- Ethylene-acrylic (AEM)
- Standard range
- -40 C to 149 C (Parker O-Ring Handbook ORD 5700)
- Special grades
- to 163 C
- Durometers
- By compound; the compound sheet states it
- Standards
- ASTM D1418 AEM; ASTM D2000 EE and EF line callouts on specific compounds
- Product
- O-rings in AS568 and ISO 3601 sizes, quoted in the compound the print names
Ranges are the handbook family figures; the compound datasheet and your application govern the final choice.
Larger and non-standard sizes: an O-ring beyond the molded size lists can be supplied as a spliced and vulcanized O-ring, which the maker joins from cord of the same compound. That page lists, family by family, which makers offer the compound as cord, and what to send for a quote.
What ethylene-acrylic is, and where it is chosen
Ethylene-acrylic rubber is a copolymer of ethylene and methyl acrylate with a small cure-site monomer; it resists oil much as polyacrylate does and reaches a lower cold limit. It seals engine and transmission oils, power-steering fluid and dry heat in automotive and off-road equipment. The Parker handbook puts the family at -40 C to 149 C, with a shorter life to 163 C, and notes a cold limit between -29 C and -40 C depending on the compound.
Where ethylene-acrylic fails
Fuels, ketones, glycol brake fluid, aromatic solvents and phosphate esters attack it, and hot water and steam are not its service (Parker rates its water and steam resistance poor to fair). Its tear strength and dynamic properties are only fair (Parker Table 2-2), so it stays in static and lightly loaded glands. Where fuel at moderate temperature is the medium, epichlorohydrin is the usual fit. Where the oil runs hotter than the family's figure, FKM takes over; where the oil carries heavy extreme-pressure additives at the top of the range, polyacrylate is the sibling to name.
How to specify
Send the AS568 dash number or the inside diameter and cross-section, the durometer, the oil by name, the coldest start temperature and the running temperature, and any ASTM D2000 line callout. The quote names the compound your print or your engineering specifies and sends its datasheet.
Sizes and forms we supply
All 369 AS568 sizes (349 general-purpose dash sizes plus the 20 boss-seal sizes) and the ISO 3601 metric series, in the durometers listed above; O-ring cord for rings spliced and vulcanized by the maker in odd diameters (static service only), where the compound is made as cord. The AS568 chart and the AS568 sizes in millimeters carry the dimensions, and the dash number guide explains the numbering.
Sources: Parker O-Ring Handbook ORD 5700, section 2.2 (read 2026-09-14) (§2.2.3); Apple Rubber, Seal Design Guide, Ethylene/Acrylic (Vamac) page (qualitative), read 2026-09-27; ASTM D1418; ASTM D2000 (documents named, not reproduced); Parker O-Ring Handbook ORD 5700, page 2-10 (hardness guidance), read 2026-09-25; Parker O-Ring Handbook ORD 5700, section 2.2.3 resistance list and Table 2-2 (page 2-9), read 2026-09-27.
Parker is a trademark of Parker Hannifin Corporation. Vamac is a trademark of its owner; no affiliation or endorsement is implied.
Frequently asked
Is Vamac the same as ethylene-acrylic?
Vamac is a trade name for ethylene-acrylic (AEM) polymer; a print that says AEM accepts any qualified ethylene-acrylic compound, and one that says Vamac is asking for that polymer maker's material.
What temperature range does ethylene-acrylic have?
The Parker O-Ring Handbook rates AEM from -40 C to 149 C, with a shorter life to 163 C; the compound datasheet governs.
Ethylene-acrylic or polyacrylate?
Both serve hot additive-laden oil. Ethylene-acrylic starts colder; polyacrylate holds the top of the oil range. Name the medium and the temperature; the quote names the compound your print or your engineering specifies.
Can it handle fuel or brake fluid?
No. Fuels, esters, ketones and glycol brake fluid swell it; FKM for fuel, EPDM for brake fluid.
Which durometer?
The compound sheet states it; for most applications the Parker handbook puts the usual choice at 70 to 80 Shore A (ORD 5700, page 2-10). The durometer guide covers the choice.
Related guides
Orders are handled under Conquest Seal's AS9100D quality management system, whose certificate scope includes distribution.
Send the part number and the quantity for Ethylene-Acrylic
The AS568 dash number or the inside diameter and cross-section, the durometer, the quantity, the medium and temperature, and any specification the print names. A Conquest representative replies. Quotes answered within one business day. A person answers (714) 632-9830, Pacific business hours.
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