1、BRITISH STANDARD BS 3279:1960 Specification for SeedlacBS3279:1960 This British Standard, having been approved by the Pigments, Paints and Varnishes Industry Standards Committee and endorsed by the Chairman of theChemical Divisional Council,was published undertheauthorityof the GeneralCouncilon 31Oc
2、tober1960 BSI 12-1999 The following BSI references relate to the work on this standard: Committee reference PVC/4 Draft for comment A(PVC) 3701 ISBN 0 580 34075 9 Co-operating organizations The Pigments, Paints and Varnishes Industry Standards Committee, under whose supervision this British Standard
3、 was prepared, consists of representatives from the following Government departments and scientific and industrial organizations: Admiralty Air Ministry Association of British Chemical Manufacturers Board of Trade* British Colour Makers Association British Railways, The British Transport Commission
4、Building Industry Distributors Crown Agents for Oversea Governments and Administrations D.S.I.R. Building Research Station D.S.I.R. Laboratory of the Government Chemist* Incorporated Institute of British Decorators Lead Oxide Convention London County Council Ministry of Aviation* Ministry of Works N
5、ational Paint Federation Oil and Colour Chemists Association* Paint Manufacturers and Allied Trades Association Post Office Research Association of British Paint, Colour and Varnish Manufacturers Royal Institute of British Architects Society of British Paint Manufacturers Ltd.* Titanium Pigment Manu
6、facturers Technical Committee White Lead Convention Zinc Development Association Zinc Pigment Development Association The Government departments and scientific and industrial organizations marked with an asterisk in the above list, together with the following, were directly represented on the Commit
7、tee entrusted with the preparation of this British Standard: British Electrical and Allied Industries Research Association British Electrical and Allied Manufacturers Association British Hat and Allied Feltmakers Research Association London Chamber of Commerce, Incorp. London Shellac Trade Associati
8、on Society for Analytical Chemistry Tropical Products Institute Individual manufacturers Amendments issued since publication Amd. No. Date CommentsBS3279:1960 BSI 12-1999 i Contents Page Co-operating organizations Inside front cover Foreword ii 1 Scope 1 2 Description 1 3 Sample 1 4 Volatile matter
9、1 5 Matter insoluble in hot alcohol 1 6 Expression of analytical results 1 7 Colour index 1 8 Matter soluble in water 1 9 Non-volatile matter soluble in cold alcohol 2 10 Wax 2 Appendix A Sampling 3 Appendix B Method for the determination of volatile matter 3 Appendix C Method for the determination
10、of matter insoluble in hot alcohol 5 Appendix D Method for the determination of colour index 7 Appendix E Method for the determination of non-volatile matter soluble in cold alcohol 7 Appendix F Method for the determination of matter soluble in water 8 Appendix G Method for the determination of wax
11、9 Figure 1 Siphon tube and adaptor 4 Figure 2 Folding of filter paper 6BS3279:1960 ii BSI 12-1999 Foreword This standard makes reference to the following British Standards: BS 410, Test sieves. BS 1957, Presentation of numerical values (fineness of expression; rounding of numbers). During recent yea
12、rs, lac has been studied internationally through the International Organization for Standardization (ISO), by various Research Institutions and Trade Organizations in different parts of the world. It has been decided to split the subject matter of BS954, the previous British Standard for all types o
13、f lac other than bleached lac, into three parts, covering seedlac, hand-made shellac and machine-made shellac, and to publish these as separate documents. Advantage has been taken of the work done at the ISO level, and the Committee responsible for the preparation of this standard desires to acknowl
14、edge its indebtedness to the sources of information thus utilized. The usual trade descriptions of the various grades of seedlac, as recognized in the United Kingdom, have been used throughout. These trade descriptions are well known internationally, and are recognized standards of the London Shella
15、c Trade Association. An attempt has been made, however, to correlate these with the designations of the Recommendations of the International Organization for Standardization: the approximate correspondence for seedlac is as follows: The mandatory requirements included in this specification are those
16、 for appearance and colour, volatile matter (moisture) and matter insoluble in hot alcohol, and methods of test are given for these. Also included are optional clauses and methods of test, operative only by agreement between purchaser and vendor, for colour index, matter soluble in water, non-volati
17、le matter soluble in cold alcohol, and wax. It will be noted that no requirements have been given for a “bleach test” or “bleachability” or for the absence of visible impurities. In the opinion of the Committee, work is not yet in a sufficiently advanced state to allow of the former, and visible imp
18、urities are effectively limited by the provisions of Clauses2 and 5. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immun
19、ity from legal obligations. Approximate U.K. grading ISO grading Golden Kusmi Special Kusmi No. I A Kusmi No. 2 B Golden Bysacki C Fine Bysacki D No equivalent E Ordinary Bysacki F Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages1 to 9 and a back c
20、over. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.BS3279:1960 BSI 12-1999 1 Mandatory clauses 1 Scope This British Standard specifies requirements for seedlac, the product obtain
21、ed by washing crushed sticklac, the natural product of the lac insect (Laccifer lacca). Unless otherwise agreed between purchaser and vendor, the seedlac shall be of Indian origin and shall be of the crop implied by the grade name employed. Six grades are specified, as follows: Golden Kusmi Kusmi No
22、. 1 Kusmi No. 2 Golden Bysacki Fine Bysacki Ordinary Bysacki 2 Description The form and condition of the material shall be as agreed between purchaser and vendor. The appearance and colour of the material shall be not inferior to those of an agreed sample, when judged by visual examination. 3 Sample
23、 For the purpose of examination under this specification samples shall be drawn, parted and prepared in the manner described inAppendix A. Only original unopened packages of shellac shall be sampled. Not less than10 per cent of the packages, selected at random from each lot of not more than200packag
24、es, shall be sampled. 4 Volatile matter The material shall not yield more than2.5per cent by weight of volatile matter when tested in the manner described inAppendix B. 5 Matter insoluble in hot alcohol The material shall not contain more than the following specified limits of matter insoluble in ho
25、t alcohol, when tested in the manner described inAppendix C. By agreement between purchaser and vendor this limit may be relaxed but under no circumstances shall it exceed the relaxed limit. 6 Expression of analytical results The results of analyses performed in accordance with the appendices to thi
26、s standard shall be expressed to the number of significant figures indicated in the specification requirements. The principles embodied in BS1957, “Presentation of numerical values (fineness of expression; rounding of numbers)”, apply to such results. Optional clauses 7 Colour index When agreed betw
27、een purchaser and vendor, the colour index of the material shall not exceed the following limits when determined in the manner described inAppendix D: 8 Matter soluble in water When agreed between purchaser and vendor, the material shall not contain more than1.0per cent by weight of matter soluble i
28、n water, when determined in the manner described in Appendix F. Grade Limit Relaxed limit per cent by weight Golden Kusmi 2.0 4.0 Kusmi No. 1 Kusmi No. 2 3.0 5.0 Golden Bysacki Fine Bysacki 3.0 6.0 Ordinary Bysacki 5.0 8.0 Grade Limit Golden Kusmi 8 Kusmi No. 1 Kusmi No. 2 10 Golden Bysacki 15 Fine
29、Bysacki 22 Ordinary Bysacki 50 BS3279:1960 2 BSI 12-1999 9 Non-volatile matter soluble in cold alcohol When agreed between purchaser and vendor, the material shall contain not less than the following amounts of non-volatile matter soluble in cold alcohol, when tested in the manner described inAppend
30、ix E: 10 Wax When agreed between purchaser and vendor, the material shall not contain more than5.5per cent by weight of wax, when determined in the manner described inAppendix G. Grade Limit per cent by weight Golden Kusmi 90.0 Kusmi No. 1 89.0 Kusmi No. 2 Golden Bysacki Fine Bysacki Ordinary Bysack
31、i 87.0 BS3279:1960 BSI 12-1999 3 Appendix A Sampling Drawing of samples Free-flowing seedlac. Take samples from different places in each package by means of a suitable tryer so as to yield a total of5kg (or 10lb) of material consisting of approximately equal portions from each package sampled. Thoro
32、ughly mix the material and heap and quarter along two diameters which intersect at right angles. Mix two opposite quarters and preserve in air-tight containers, seal and label as the “Original observation sample”. If necessary, further sub-divide by quartering to form a number of original observatio
33、n samples. Part the other two quarters of the material as described below to form the analysis sample. Blocky or matted seedlac. Take small pieces not more than1.2 in (3cm) across from different places in each package by chipping or other suitable means so as to yield a total of5kg (or10lb) of mater
34、ial consisting of approximately equal portions from each package sampled. Thoroughly mix the material and heap and quarter along two diameters which intersect at right angles. Mix two opposite quarters and preserve in air-tight containers, seal and label as the “Original observation sample”. If nece
35、ssary, further sub-divide by quartering to form a number of original observation samples. Part the other two quarters of the material as described below to form the analysis sample. Preparation of samples Thoroughly mix the material obtained above, and heap and quarter along two diameters which inte
36、rsect at right angles. Mix two opposite quarters and grind the mixture to pass entirely through an 8mesh BS test sieve 1) . Thoroughly mix and twice divide by quartering into four samples, each of approximately300g (or11oz). Place these samples in air-tight containers, seal and label each as “Analys
37、is sample”. a) Sample for determination of volatile matter. Grind an adequate amount (40to50g) of the “Analysis sample” to pass entirely through an18mesh BS test sieve 1) , taking all precautions to avoid loss of volatile matter. Place in an air-tight container and label “Sample for volatile matter
38、determination”. b) Prepared sample for all determinations other than volatile matter. Grind an adequate amount of the “Analysis sample” to pass entirely through a36mesh BS test sieve 1) . Transfer to an air-tight container and label as “Prepared sample for all determinations other than that for vola
39、tile matter”. Appendix B Method for the determination of volatile matter Principle The volatile matter content is determined by heating a weighed portion of the sample at41 1 C for4hours and then keeping it over concentrated sulphuric acid in vacuo for18 hours. Procedure Weigh, to an accuracy of0.00
40、05g, a clean, dry, flat-bottomed dish of about75mm diameter, provided with a ground glass cover. Transfer about2g of the sample reserved for this purpose (seeAppendix A) into the dish and re-weigh to the same accuracy. Place the dish and its cover separately in a well-ventilated oven maintained at41
41、 1 C for4hours. At the end of this period, transfer the dish and cover to a vacuum desiccator containing concentrated sulphuric acid. Immediately evacuate the desiccator and continue drying in vacuo for18 hours. Remove the dish and immediately replace the cover and weigh to an accuracy of0.0005g. Ex
42、press the loss in weight as a percentage of the weight of the sample taken. Calculation 1) BS 410, “Test sieves”. Volatile water, per cent by weight where W = weight in grammes of sample taken, and W 1 = weight in grammes of sample after drying. 100WW 1 () W - =BS3279:1960 4 BSI 12-1999 Dimensions i
43、n millimetres Figure 1 Siphon tube and adaptorBS3279:1960 BSI 12-1999 5 Appendix C Method for the determination of matter insoluble in hot alcohol Apparatus a) Siphon tube 2) , of glass, of the Knoefler type, having minimum internal dimensions of52mm height and32mm diameter, resting in an adaptor tu
44、be in such a way that the siphon tube is surrounded by the ascending vapours of the boiling solvent (Figure 1). b) Condenser, of any convenient pattern. c) Flask, of any convenient size. d) Filter paper, 12.5cm diameter, medium grade 3) . e) Weighing bottles, of glass, height801mm, diameter401mm wit
45、h ground glass stoppers. Assembly of apparatus Assemble the siphon tube, adaptor, condenser and flask, using corks or ground glass joints, so that the solvent can be kept boiling in the flask and its vapour passed upwards, by way of the adaptor, to the condenser and the refluxing solvent run from th
46、e condenser into the cup of the siphon tube. Reagent Alcohol, 95 per cent (v/v) ethanol or95 per cent (v/v) industrial methylated spirit 4) . Procedure Fold a filter paper so that it forms a completely closed envelope, as illustrated inFigure 2. Mark this paper, S, for sample: wrap it closely in a s
47、econd filter paper marked C, for counterpoise. Separate the filter papers and dry in an oven at100 2 C for30minutes. Rapidly transfer to weighing bottles which have been kept in a desiccator over concentrated sulphuric acid. Place each bottle and its contents back in the desiccator for20minutes, the
48、n weigh by counterpoise, preferably using a rapid weighing balance of the aperiodic type. Weigh4.5 to5.5g of the prepared sample (seeAppendix A) to an accuracy of0.01g and place in the filter paper envelope, S, and fold in the original folds, taking care not to leave any channel through which finely
49、 divided material might afterwards escape. Again enclose in the paper, C, and secure with thread. Place the resulting package in a100ml beaker and cover it with alcohol. Allow to stand overnight at room temperature. Place the package in the cup of the siphon tube and extract continuously with hot alcohol for4hours. Keep the package wholly below the surface of the alcohol when the cup is full. The exact time taken for the cycle of filling and emptying the cup of the siphon tube is not critic
