O-ring material
Polyacrylate O-Rings
Polyacrylate O-rings are the acrylic rubber (ACM) seal built for one job: hot petroleum oil loaded with the sulfur-bearing extreme-pressure additives that harden nitrile. The Parker® O-Ring Handbook rates the family from -21 C to 177 C, and Conquest supplies polyacrylate O-rings in AS568 and metric sizes as a distributor, quoted in the compound the print names.
- Family
- Polyacrylate (ACM)
- Standard range
- -21 C to 177 C (Parker O-Ring Handbook ORD 5700)
- Durometers
- 70 Shore A quoted as standard; other hardnesses by compound
- Standards
- ASTM D1418 ACM; ASTM D2000 DH 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 polyacrylate is, and where it is chosen
Polyacrylate is a copolymer of acrylic esters with a small cure-site monomer, a saturated backbone that shrugs off oxidation and ozone. Its reason for being is automatic transmission fluid and hypoid gear oil at the temperatures a gearbox reaches, where the extreme-pressure additives attack nitrile and even HNBR. It holds up in hot mineral oil, petroleum grease and dry heat, and it is a common transmission and axle callout. The Parker handbook puts the family at -21 C to 177 C.
Where polyacrylate fails
Water, steam, glycols and alcohols attack it, and it is poor below about -21 C, so it is never a general-purpose seal. Its mechanical strength and compression set are below nitrile's, which keeps it out of demanding dynamic glands. Where the oil is hot but carries no aggressive additive, HNBR or FKM serves a wider range; where the additive package is the problem, polyacrylate is the usual fit. The ethylene-acrylic family covers similar oils with better cold flexibility.
How to specify
Send the AS568 dash number or the inside diameter and cross-section, the durometer, the oil by name, the temperature and any ASTM D2000 line callout the print carries. 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 metric chart 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) (§2.2.11); Apple Rubber, O-ring material selection guide (what the family is and where it is used, qualitative), read 2026-09-14; ASTM D1418; ASTM D2000 (documents named, not reproduced).
Parker is a trademark of Parker Hannifin Corporation. No affiliation or endorsement is implied.
Reviewed by Grant Midstokke, Conquest Seal Corporation. Last updated September 2026. Material ranges are the published references named beside them; the compound datasheet and your application govern the final choice.
Frequently asked
What is polyacrylate used for?
Seals in automatic transmissions, axles and gearboxes running hot oil with extreme-pressure additives that harden nitrile.
What temperature range does polyacrylate have?
The Parker O-Ring Handbook rates ACM from -21 C to 177 C; the compound datasheet governs.
Can polyacrylate handle water or steam?
No. Water, steam, glycols and alcohols attack it; EPDM or a suitable FKM serves those.
Polyacrylate or ethylene-acrylic?
Both serve hot additive-laden oil. Ethylene-acrylic is more flexible in the cold; 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.
Which durometer?
70 Shore A is the hardness quoted as standard. The durometer guide covers the choice.
Related guides
Send the part number and the quantity for Polyacrylate
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.
Request a quote