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I am looking at a rubber compound with the following description:

A13 B13 C20 F17 K11 L14

I cannot find the meaning for "A" and "L".

I am not a chemist.

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closed as off-topic by Jan, Melanie Shebel, airhuff, Todd Minehardt, Pritt Balagopal Aug 12 '17 at 7:36

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    $\begingroup$ I don't think either of those are elements. $\endgroup$ – M.A.R. ಠ_ಠ Aug 11 '17 at 9:16
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    $\begingroup$ Whatever it is it does not make sense as a chemical formula. $\endgroup$ – Jan Aug 11 '17 at 9:17
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    $\begingroup$ @M.A.R. These are not chemical elements. It looks like they are ASTM D2000 specs. $\endgroup$ – andselisk Aug 11 '17 at 9:19
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    $\begingroup$ I'm voting to close this question as off-topic because it has nothing to do with chemistry. Just because something looks like a chemical formula to some laymen does not mean it is one. The answer confirms the suspicion. $\endgroup$ – Jan Aug 12 '17 at 1:53
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TL;DR I think you might need two more things to interpret this line: the first code part of the standard, and the standard itself - ASTM D2000 (needs to be purchased).


These descriptors are not chemical elements, they seem to be the part of ASTM D2000 "Standard Classification System for Rubber Products in Automotive Applications", so what you are looking at is the suffix part of the full spec, which is usually written as:

enter image description here

The part after ASTM D2000 includes information about units of measure, grade durometer hardness and tensile strength. This is a rather essential sequence and if you don't have it it is impossible to define the exact meaning of the given suffix, which are:

A: Heat resistance;
B: Compression set, standard test specimen cut from a slab;
C: Ozone or weather resistance;
F: Low-temperature resistance;
K: Adhesion;
L: is not explicitly defined in D2000−12, probably falls into Z: Any special requirement, which shall be specified in detail.

Each suffix letter should preferably be followed by two suffix numbers [...] The first suffix number always indicates the test method; time of test is part of the method [...]. The second suffix number, if used, always indicates the temperature of test [...]. Where three-digit numbers are required, they are separated by a dash.

Exact characteristics of the rubber can be found in numerous tables from ASTM D2000-12 datasheet, but without having the first part of the descriptor there is not much to be done.

The exact set of suffixes you provided can be found in this report, the rubber they refer to is ASTM D2000 5AA425 A13 B13 C20 F17 K11 L14 used for shock absorbers.

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