This specification establishes the requirements for first grade concentrated natural rubber latex of the following categories: Category 1, centrifuged Hevea natural latex preserved with ammonia only or by formaldehyde followed by ammonia; Category 2, creamed Hevea natural latex preserved with ammonia only or by formaldehyde followed by ammonia; Category 3, centrifuged Hevea natural latex preserved with low ammonia with other necessary preservatives; and Category 4, centrifuged, or centrifuged and creamed, guayule latex, or other natural rubber latex, containing a specified dry weight amount of latex, with ammonia or other hydroxide, with other necessary preservatives and stabilizers. This specification applies to natural latex sources other than Hevea brasiliensis but does not apply to compounded latex concentrates. Materials shall be tested by analytical procedures that determine the following chemical properties an substances: total solids; dry rubber content; protein content; total alkalinity; viscosity; sludge content; coagulum content; KOH number; pH; mechanical stability; copper and manganese; density; volatile fatty acids; boric acid; and dry films.

1.1 This specification covers requirements for first grade concentrated natural rubber latex (see Table 1) of the following categories:

Category 1-Centrifuged Hevea natural latex preserved with ammonia only or by formaldehyde followed by ammonia.

Category 2-Creamed Hevea natural latex preserved with ammonia only or by formaldehyde followed by ammonia.

Category 3-Centrifuged Hevea natural latex preserved with low ammonia with other necessary preservatives.

Category 4-Centrifuged, or centrifuged and creamed, guayule latex, or other natural rubber latex, containing less than 200 g total protein per gram dry weight of latex, with ammonia or other hydroxide, with other necessary preservatives and stabilizers.

1.2 This specification is not necessarily applicable to latices prepared or preserved by other methods, and shall not be construed as limiting the desirability or usefulness of other categories of latices. It does apply to natural latex sources other than Hevea brasiliensis but does not apply to compounded latex concentrates.

1.3 The analytical procedures applicable to the specifications are included and appear in the following order:

1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.