BS 6057-1.2:1990 pdf free download.Rubber latices Part 1: Specification and coding Section 1.2 Specification for evaporated, preserved natural rubber latices.
1 Scope
BS 6057-1.2 gives specifications for natural rubber latex concentrate which has been concentrated by evaporation. It does not apply to natural rubber latex concentrates which have been concentrated by centrifuging or creaming, or to latices from natural sources other than Hevea brasiliensis, or to compounded latex or vulcanized latex.
BS 6057-1.2 covers requirements for evaporated natural rubber latex concentrates of the following types:
NR latex, type HA evaporated: Evaporated latex concentrate preserved with ammonia only or with ammonia together with other preservative(s), with an alkalinity of at least 0,60 % (rn/rn) with respect to the latex.
NR latex, type KHS evaporated: Evaporated latex concentrate preserved with potassium hydroxide and having a nominal total solids content of 73 % (rn/rn).
NR latex, type KLS evaporated: Evaporated latex concentrate preserved with potassium hydroxide and having a nominal total solids content of 68 % (rn/rn).
2 Normative references
The following standards contain provisions which. through reference in this text, constitute provisions of BS 6057-1.2. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on BS 6057-1.2 are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain registers of currently valid International Standards.
ISO 35:1989, Natural rubber latex concentrate — Determination of mechanical stability.
ISO 123:1985. Rubber latex— Sampling. ISO 124:1985, Rubber latices— Determination of total solids content.
ISO 125:1990, Natural rubber latex concentrate — Determination of alkalinity.
Iso 126:1989, Natural rubber latex concentrate — Determination of dry rubber content.
Iso 506:1985, Natural rubber latex concentrate— Determination of volatile fatty acid number. ISO 706:1985, Rubber latex— Determination of coagulurn content (sieve residue).
ISO 2005:1985, Natural rubber latex concentrate — Determination of sludge content.
ISO 7780:1987, Rubbers and rubber latices — Determination of manganese content — Sodium periodate photometric methods.
ISO 8053:1986, Rubber and latex— Determination of copper content — Photometric method.
3 Requirements
The latex concentrate shall conform to the requirements given in Table 1.
In the case of NR latex concentrate, type HA evaporated, the chemical nature and approximate quantity of any preservative(s) other than ammonia shall be stated. NR latex concentrate, type HA evaporated, shall not contain fixed alkali added at any stage in its production.
4 Sampling
The latex concentrate shall be sampled by one of the methods specified in ISO 123.