ISO 56-2-1979 pdf free.Shellac—Specification.
1.SCOPE AND FIELD OF APPLICATION
1.1 This International Standard specifies requirements andcorresponding methods of test for machine-made shellac.
1.2This International Standard is intended chiefly tocover the technical provisions for guidance in the purchaseof the material，but does not include all the necessaryprovisions of a contract.
1.3 The limits prescribed in this International Standardare limits for rejection.
2.DEFINITIONS:For the purpose of this International Standard,thefollowing definitions apply.
2.1 sticklac : The natural product of lac insects.
2.2seedlac : The product obtained by washing crushedsticklac.
2.3shellac : The product obtained by refining seedlac byheat process or by solvent process or by both heat andsolvent processes.
2.4approved sample : The sample aggreed upon betweenthe purchaser and the supplier as the standard for colourand appearance.
3 FORM AND CONDITION:Machine-made shellac shall be in the form of flakes, sheets,buttoms,or any other from agreed between the purchaserand the supplier.4.Five grades in each of types l and 11, namely grades 1,2,3,4 and 5 are specified.Four grades in each of types liand lV , namely grades 1,2,3, and 4 are specified.
5.1 Matter insoluble in hot alcohol:Machine-made shellac shall not contain matter insoluble inhot alcohol, determined by either of the methods specifiedinannex A, as agreed between the purchaser and thesupplier, in excess of the limits given in table 1.
5.2.Rosin:Machine-made shellac shall not contain any rosin，whentested by the method specified in annex B.
5.3.Orpiment:
5.3.1 Machine-made shellac shallnot contain anyorpiment, when tested by the method specified in annex C,except when a specified percentage is agreed to between thepurchaser and the supplier, in which case the determinationshall be carried out as specified in annex D, method l.
5.3.2When the material is required for food or drugpreparations,the determination of traces of arsenic,toosmall for titration by method l in annex D, shall be carriedout by method ll in annex D.
6.OPTIONAL REQUIREMENTS:The optional requirements given below shall be subject toagreement between the purchaser and the supplier.
6.1.Volatile matter (moisture):Machine-made shellac shal not contain more than 2,0 %(m/m) volatile matter (moisture) as determined by themethod specified in annex E.
6.2.Colour index or colour and appearance
6.2.1 The colour index of machine-made shellac,asdetermined by the method specified in annex F, shall notexceed the limits given in table 2.ISO 56 pdf download.