ISO 55:1977 download.Seedlac – Specification.
0.1 The usual trade descriptions of seedlac are based on the Indian names of the host trees, the season of cropping the sticklac, visual differences or a combination of any of these. The use of these grade designations led to con fusion and some marketing difficulties. When ISO/R 55 was prepared in 1957, it was decided to adopt only seven grades which were independent of the names of host trees or seasons. However, the expectation that the ISO grades for seedlac would be increasingly adopted in trade and ultimately replace the traditional grade designations has not come about. A new system has theeefore been adopted in ISO 55 so that seedlac can now be completely identified by a combination of the ISO grade and the trade grade. In this revision, it has been found possible to reduce the number of ISO grades from seven to five.
0.2 For matter insoluble in hot alcohol, two limits are prescribed, in line with trade practice : a basic limit and a relaxed limit. The relaxed limit shall be the limit for rejection.
0.3 The requirement for non-volatile matter soluble in cold alcohol has not been retained as this requirement is applied in practice to waste products of lac only.
0.4 One of the requirements for seedlac, namely that for matter Insoluble in hot alcohol, is included in ISO 55 as an essential clause. The remainder, namely those for volatile matter (moisture), colour, bleach index and bleachability, matter soluble in water, wax and ash, are optional.
0.5 For determination of bleach index and bleachability, two methods are practised. One has been developed in India
the other in the U.S.A. Th. method to be followed f or the determination of bleach index and bleachability shall be subject to agreement between the purchaser and the supplier.
0.6 For the purpose of deciding whether a particular requirement of this International Standard is complied with, it is necessary for the final value, observed or calculated, expressing the result of test or analysis to be rounded off to the same number of places as that in the specified value, it being always understood that the analyst will carry out his determination to at least one place more than in the specified value.
1 SCOPE AND FIELD OF APPLICATION
1.1 ISO 55 specifies requirements and methods of test for seedlac.
1.2 ISO 55 is intended chiefly to cover the technical provisions for guiding the purchase of the material, but does not include all the necessary provisions of a contract.
1.3 The limits specified in ISO 55 are limits for rejection (see 0.2).
For-the purposes of ISO 55, the following definitions apply:
2.1 sticklac: The natural product of lac insects.
2.2 seedlac: The product obtained by washing crushed sticklac.
2.3 approved sample: The sample agreed upon between the purchaser and the vendor as the standard for colour and appearance.
3 FORM AND CONDITION
The form and condition of seedlac are subject to agreement between the purchaser and the supplier.
Five grades of seedlac, namely Special, A, B, C and D are specified. Further, if required by the purchaser, the names of the grades as prevalent in trade shall be Indicated in addition, in parentheses, as shown below:
— Grade Special (Golden Kusmi);
— Grade B (Kusmi No. 2).
The correspondence between ISO grades and trade grades Is shown in table 1.
5 MANDATORY REQUIREMENT
Matter Insoluble in hot alcohol
Seedlac shall not contain more than the basic limits of matter insoubIe in hot alcohol specified In table 2, when determined by either of the methods described in annex A, as agreed between the purchaser and the supplier. By agree• ment between the purchaser and the supplier, the basic limit may be relaxed but It shall not In any case exceed the relaxed limit as shown in table 2.
6 OPTIONAL REQUIREMENTS
6.1 Volatile matter (moisture)
Seedlac shall not contain more than 2,5 % (rn/rn) of volatile matter (moisWre) as determined by the method described In annex B.
6.2 Colour index
The colour index of seedlac, as determined by the method described In annex C, shall not exceed the limits given in table 3.
Alternatively, the appearance and colour of seedlac shall not be inferior to those of an approved sample when judged by visual examination.
6.3 Bleach index and bleachability
The bleach index of seedlac shall be determined or the bleachability test for seedlac shall be carried out, if either is agreed betiimen the purchaser and the supplier, In ac cordance with such methods as may be agreed between them (see 0.5).
6.4 Matter soluble In water
Seedlac shall not contain more than 1 % (rn/rn) of matter soluble in water, and the aqueous extract shall be neutral to methyl red. Matter soluble in water shall be determined by the method described in annex D.
The limits and methods of test for ash content of seedlac shall be subject to agreement between the purchaser and the supplier.
Seedlac shall not contain more than 5,5 % (rn/rn) of wax when determined by the method described In annex E.
Samples shall be taken in the manner described In annex F.
ISO 55:1977 download.Seedlac – Specification.