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Normas ASTM – AENOR
ASTM D1076-14

ASTM D1076-14

Standard Specification for Rubber—Concentrated, Ammonia Preserved, Creamed, and Centrifuged Natural Latex

Fecha:
2016-01-22 /Historical
Superseeded by:
Abstract:

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.

Significance and Use:

4.1 This specification denotes limits on the 4 categories of latex as defined in the scope and defines the test methods to use for the specified properties. These test methods may be used for production control or for referee purposes.

Scope:

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

(A) Dry rubber content by definition and use is the acid coagulable portion of latex after washing and drying.
(B) It is accepted that KOH numbers for boric acid preserved latices will be higher than normal, equivalent to the amount of boric acid in the latex.
(C) Blue or gray color usually denotes iron contamination caused by improper storage in containers.

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 µg total protein per gram dry weight of latex, with ammonia or other hydroxide, with other necessary preservatives and stabilizers.

Category 5—Centrifuged Hevea natural latex treated with aluminum hydroxide or by other means, preserved with ammonia only or by formaldehyde followed by ammonia containing less than 0.5 % non-rubber content.

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:

 

Section

    Sampling

6 and 7

    Total Solids

8

    Dry Rubber Content

9

    Protein Content

10

    Total Alkalinity

11

    Viscosity

12

    Sludge Content

13

    Coagulum Content

14

    KOH Number

15

    pH

16

    Mechanical Stability

17

    Copper and Manganese

18

    Density

19 – 31

    Volatile Fatty Acids

32 – 36

    Boric Acid

37

    Dry Films

38

    Precision for All Test Methods

39

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

57,64
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