ISO 55:1977
(Main)Seedlac — Specification
Seedlac — Specification
Gomme laque en grains — Spécification
General Information
Standards Content (Sample)
INTERNATIONAL STANDARD -
INTERNATIONAL ORGANIZATION FOR STANDARDlZATlON ’d4EX~YHAPOAHA5l OPTAHW3AUWf no CTAHAAPTW3AUWW l ORGANIZATION INTERNATIONALE DE NORMALISATION
Seedlac - Specification
Gomme iaque en grains - Spe ’cification
First edition - 1977-1 l-01
UDC 668.447.31
Ref. No. IS0 55-1977 (E)
ic
-
Descriptors : shellac, materials specifications, tests, chemical tests,, sampling.
Price based on 13 pages
Preisgr. 19
---------------------- Page: 1 ----------------------
FOREWORD
IS0 (the International Organization for Standardization) is a worldwide federation
of national standards institutes (IS0 member bodies). The work of developing
International Standards is carried out through IS0 technical committees. Every
member body interested in a subject for which a technical committee has been set
up has the right to be represented on that committee. International organizations,
governmental and non-governmental, in liaison with ISO, also take part in the work.
Draft International Standards adopted by the technical committees are circulated
to the member bodies for approval before their acceptance as International
Standards by the IS0 Council.
International Standard IS0 55 was developed by Technical Committee ISO/TC 50,
Lac, and was circulated to the member bodies in February 1976.
It has been approved by the member bodies of the following countries :
Austria Mexico Thailand
Czechoslovakia Netherlands Turkey
Egypt, Arab Rep. of Romania United Kingdom
Sweden
India
No member body expressed disapproval of the document.
This International Standard cancels and replaces IS0 Recommendation R 55-1957,
of which it constitutes a technical revision.
Acknowledgement is due for the assistance that has been derived from the specifi-
cations and publications of the American Society for Testing and Materials, the
American Bleached Shellac Manufacturer ’s Association, the United States Shellac
Importer ’s Association, the British Standards Institution, the Agricultural Marketing
Adviser to the Government of India, Messrs. Angelo Brothers, Ltd., Calcutta, and
the Indian Lac Research Institute. Considerable assistance has been derived also
from A Handbook of Shellac Analysis, by M. Rangaswami and H. K. Sen, issued
by the Indian Lac Research Institute.
0 International Organization for Standardization, 1977 l
Printed in Switzerland
ii
---------------------- Page: 2 ----------------------
Page
CONTENTS
...........................................
0 Introduction 1
................................
1 Scope and field of application 1
............................................
2 Definitions. 1
......................................
3 Form and condition. 1
2
4 Grades .
.................................... 2
5 Mandatory requirement
.................................... 2
6 Optional requirements.
7 Sampling. 2
An nexes
................... 3
A Determination of matter insoluble in hot alcohol
...................... 8
B Determination of volatile matter (moisture).
............................... 9
C Determination of colour index
D Determination of matter soluble in water and of neutrality of
......................................... IO
aqueous extract
............................... I I
E Determination of wax content
F Sampling.12
. . .
III
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This page intentionally left blank
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INTERNATIONAL STANDARD
IS0 55-1977 (E)
Seedlac - Specification
0.6 For the purpose of deciding whether a particular,
0 INTRODUCTION
requirement of this International Standard is complied
0.1 The usual -trade descriptions of seedlac are based on
with, it is necessary for the final value, observed or calcu-
the Indian names of the host trees, the season of cropping
lated, expressing the result of test or analysis to be rounded
the sticklac, visual differences or a combination of any
off to the same number of places as that in the specified
of these. The use of these grade designations led to con-
value, it being always understood that the analyst will
fusion and some marketing difficulties. When lSO/R 55
carry out his determination to at least one place more than
was prepared in 1957, it was decided to adopt only seven
in the specified value.
grades which were independent of the names of host trees
or seasons. However, the expectation that the IS0 grades
1 SCOPE AND FIELD OF APPLICATION
for seedlac would be increasingly adopted in trade and
ultimately replace the traditional grade designations has
I.1 This International Standard specifies requirements
not come about. A new system has thelaefore been adopted
and methods of test for seedlac.
in this International Standard so that seedlac can now be
completely identified by a combination of the IS0 grade
1.2 This International Standard is intended chiefly to
and the trade grade. In this revision, it has been found
cover the technical provisions for guiding the purchase of
possible to reduce the number of IS0 grades from seven
the material, but does not include all the necessary pro-
to five.
visions of a contract.
0.2 For matter insoluble in hot alcohol, two limits are
1.3 The limits specified in this International Standard are
prescribed, in line with trade practice : a basic limit and a
limits for rejection (see 0.2).
relaxed limit. The relaxed limit shall be the limit for
rejection.
2 DEFINITIONS -
0.3 The requirement for non-volatile matter soluble in
For the purposes of this International Standard, the follow-
cold alcohol has not been retained as this requirement is
ing definitions apply :
applied in practice to waste products of lac only.
2.1 sticklac : The natural product of lac insects.
0.4 One of the requirements for seedlac, namely that for
matter insoluble in hot alcohol, is included in this Inter-
2.2 seedlac : The product obtained by washing crushed
national Standard as an essential clause. The remainder,
sticklac.
namely those for volatile matter (moisture), colour, bleach
index and bleachability, matter soluble in water, wax and
2.3 approved sample :
ash, are optional. The sample agreed upon between
the purchaser and the vendor as the standard for colour
and appearance.
0.5 For determination of bleach index and bleachability,
two methods are practised. One has been developed in India
and the other in the U.S.A. The method to be followed for
3 FORM AND CONDITION
the determination of bleach index and bleachability shall be
The form and condition of seedlac are subject to agreement
subject to agreement between the purchaser and the
between the purchaser and the supplier.
supplier.
1
---------------------- Page: 5 ----------------------
IS0 55-1977 (E)
6 OPTIONAL REQUIREMENTS
4 GRADES
Five grades of seedlac, namely Special, A, B, C and D are
6.1 Volatile matter (moisture)
specified. Further, if required by the purchaser, the names
of the grades as prevalent in trade shall be indicated in
Seedlac shall not contain more than 2,5 % (m/m) of volatile
addition, in parentheses, as shown below :
matter (moisture) as determined by the method described
in annex B.
- Grade Special (Golden Kusmi);
6.2 Colour index
- Grade B (Kusmi No. 2).
The colour index of seedlac, as determined by the method
The correspondence between IS0 grades and trade grades
described in annex C, shall not exceed the limits given in
is shown in table 1.
table 3.
TABLE 3
TABLE 1
4
.
Colour index
Grade
IS0 grade Trade grade
(maximum)
1
L
Special i) Golden Kusmi
8
I
ii)
Golden Bysacki 10
iii)
Grade I, Class A 12
18
30
B i) Kusmi No. 2
Alternatively, the appearance and colour of seedlac shal
ii) Manbhum Fine Bysacki
not be inferior to those of an approved sample when judged
by visual examination.
iii) Grade I, Class B
Fine By sac ki
C i)
6.3 Bleach index and bleachability
ii) Grade I I, Class B
The bleach index of seedlac shall be determined or the
Ordinary Bysacki
D i)
bleachability test for seedlac shall be carried out, if either
is agreed between the purchaser and the supplier, in ac-
cordance with such methods as may be agreed between
them (see 0.5).
5 MANDATORY REQUIREMENT
6.4 Matter soluble in water
Matter insoluble in hot alcohol
Seedlac shall not contain more than 1 % (m/m) of matter
soluble in water, and the aqueous extract shall be neutral
Seedlac shall not contain more than the basic limits of
to methyl red. Matter soluble in water shall be determined
matter insoluble in hot alcohol specified in table 2, when
by the method described in annex D.
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
6.5 Ash
limit may be relaxed but it shall not in any case exceed the
The limits and methods of test for ash content of seedlac
relaxed limit as shown in table 2.
shall be subject to agreement between the purchaser and
the supplier.
TABLE 2
6.6 Wax
Basic limit Relaxed limit
Grade
% (m/m) % Mm)
I I Seedlac shall not contain more than 5,5 % (m/m) of wax
when determined by the method described in annex E.
Special
zo 3,o
A 3s 4,o
B 3s 4,o
c 3,o 5,o
7 SAMPLING
D 5,o 7s)
Samples shall be taken in the manner described in annex F.
b
2
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IS0 55-1977 (E)
ANNEX A
(See clause 5
DETERMINATION OF MATTER INS0 .UBLE IN HOT ALCOHOL
A.1 PRINCIPLE A.: 2 Apparatus
The matter insoluble in hot alcohol is determined by
A.2.2.1 Condenser, all glass, of the type and dimensions
extracting a known mass of seedlac with 95 % (V/V) ethanol
shown in figure 1, with the tip cut at an angle of 45 ’. The
and determining the percentage of the undissolved residue
condenser shall have two holes in its tip to hold the siphon
by either of the two methods described below, as may be
tube (A.2.2.2).
agreed.
A.2 METHOD I
A.2.2.2 Siphon tube, of glass, of the type and dimensions
shown in figure 1. The siphon tube shall have two holes
A-2.1 Reagent
near the top for a wire to be fastened to the condenser tip,
Alcohol : 95 % (V/V) ethanol, or 95 % (V/V) denatured leaving about 6 mm space between the top of the tube and
the condenser tip.
spirit.
Dimensions in millimetres
All dimensions are approximate
# int. 32 2 03.
$ int. 3 to 3,5
Siphon tube
Condenser Filter tube
FIGURE 1 - Extraction apparatus for determining matter insoluble in hot alcohol - Method I
3
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IS0 55-1977 (E)
A.2.2.5 Extraction cartridges, of fat-free paper, approxi-
A-2.2.3 Conical flask, heat-resistant, wide-mouthed, prefer-
mately 25 mm in diameter and approximately 60 mm in
ably of borosilicate glass, approximately 175 mm in height
height.
and approximately 50 mm in inside diameter at the top.
A.2.2.6 Weighing bottle, glass-stoppered,
approxi-
The flask shall be fitted with a tight-fitting cork 25 mm in
mately 80 mm in height and approximately 40 mm in
depth and bored to fit the stem of the condenser. The
diameter.
bottom of the cork shall be just above the holes for the
wire in the condenser. To support the flask, a suitable ring
A.2.2.7 Hot water bath, made of about 0,9 mm thick
support with iron clamp and nickel-chromium or iron
copper or stainless steel, having a width of approxi-
gauze shall be used. The gauze shall not have asbestos
mately 100 mm and other dimensions as given in figure 2.
covering.
The cover shall have a flanged hole, 57 + 1 mm in diameter,
for a 200 ml beaker, and also a hole 35 + 1 mm in diameter
through which the top of the filter tube projects. Directly
A.2.2.4 Carbon filter tube, of the type and dimensions
below this hole, in the bottom of the bath, there shall be
shown in figure 1, with a light spiral spring at the bottom
a flanged hole, 25 + 1 mm in diameter, to hold the rubber
to hold up the extraction cartridge. The stem of the filter
stopper, through which the stem of the filter tube extends,
tube shall be fitted with a rubber stopper and shall be
to discharge into the bottle or flask. The hot water bath
firmly supported in a hot water bath.
shall be mounted on a low tripod or stand.
Dimensions in millimetres
All dimensions are approximate
$ ext. 32 +, I
@ 35 + 1’
f
Rubber stopper
FIGURE 2 - Hot water bath for insoluble matter test - Method I
---------------------- Page: 8 ----------------------
IS0 55-1977 (E)
wash-bottle kept hot on the water bath. Finally, wash the
A.2.2.8 Beaker, tall-form, 200 ml capacity.
cartridge from the top downwards with a fine stream of
hot alcohol. A complete washing and transfer from the
A.2.2.9 Desiccator, containing sulphuric acid, p I,84 g/ml,
original beaker will require at least 75 ml of hot alcohol.
as desiccant.
A.2.2.10 Drying oven, maintained at 100 + 2 “C. A.2.4.4 Transfer the cartridge containing the insoluble
matter to the extraction apparatus, place 125 ml of alcohol
in the extraction flask and connect up the apparatus. Start
A.2.2.11 Weighing balance, accurate to 0,l mg.
the water flowing through the condenser, making sure that
there is an adequate supply for efficient condensation.
A.2.2.12 Gas burner, low form, adjustable, Bunsen type,
Light the burner and time the extraction from the first
carrying a draught shield, or any other suitable heating
emptying of the siphon, running the extraction for exactly
device.
I. h. Adjust the rate of heating so that a complete filling
and emptying of the siphon tube takes place every 2 min, as
determined by a stoplwatch or preferably by a good two-
A-2.3 Preparation of extraction cartridge
minute sand-glass, one for each extraction apparatus.
A.2.3.1 Place 125 ml of the alcohol (A.2.1) in the
A.2.4.4.1 In this way exactly 30 cycles per hour are
flask (A.2.2.3) and a new cartridge (A.2.2.5) in the siphon
accomplished. If this cycle rate is not meticulously main-
tube (A.2.2.2). Introduce the siphon tube into the flask and
tained, neither check results on duplicate samples in the
connect it to the condenser (A.2.2.1), making sure that
same laboratory nor concordant figures from one labora-
there is ample flow of cold water through the condenser.
tory to another can be obtained, even when working on the
Adjust the rate of heating so as to give a cycle of filling and
same standard sample. It is also necessary to protect the
emptying in the siphon tube every 2 min and extract
apparatus from draughts while in operation, otherwise the
for 30 min. Dry the cartridge in the oven (A.2.2.10)
proper cycle rate cannot be maintained.
at 100 +, 2 “C. At the end of 2 h, weigh it in a tared
weighing bottle (A.2.2.6), which has been kept in the
desiccator over sulphuric acid (A.2.2.9), lifting the stopper
A.2.4.4.2 Occasionally, seedlacs are encountered which do
of the bottle momentarily before weighing. Repeat the
not yield the required number of 30 siphonings per hour,
operations of drying, for periods of 1 h, and weighing,
due to slow filtration, in these cases, continue the ex-
until the loss in mass between two successive weighings
traction until 30 siphonings have been accomplished or
does not exceed 2 mg.
repeat the test with a 2 g test portion and report the sample
as abnormal or slow filtering.
A.2.3.2 Use only new cartridges. A number of cartridges
may be extracted, dried, weighed and kept in weighing
Remove the cartridge, drain in an upright position
A.2.4.5
bottles in a desiccator until needed for use.
on filter paper and dry in the oven at 100 + 2 “C. After
drying for 2 h, place it in the weighing bottle, cool in the
desiccator over sulphuric acid and weigh, removing the
A.2.4 Procedure
stopper momentarily just before weighing. Repeat the
operations of drying, for periods of 1 h, and weighing,
A.2.4.1 Before analysis, thoroughly mix the test sample until the loss in mass between two successive weighings
(see F.3.1) by rolling on paper, at least ten times, to ensure does not exceed 2 mg. From the mass of the residue and
the mass of the sample, calculate the percentage of in-
uniformity of the test sample. Weigh, directly from the
soluble matter. Use the lowest mass in the caiculation.
paper, 4,5 to 5,5 g of the sample, to an accuracy of 0,Ol g,
place in the beaker (A.2.2.8), add 125 ml of the alcohol
(A.2.1), cover with a watch-glass and place on the hot water
bath (A.2.2.7) (see figure 2). Boil the solution vigorously
for 30 min to ensure complete solution of the seedlac and
A.2.5 Calculation
dispersion of wax. Keep the volume of alcohol constant by
The matter insolu ble in hot alcohol presse d as a per-
adding hot alcohol from a wash bottle, washing down the I ex
centage by mass, is given by th e formu la
sides of the beaker.
A.2.4.2 Meanwhile, place an extracted and weighed
IOOm,
cartridge in the filter tube. Maintain the hot water around
the tube at not less than 90 “C. Wet the cartridge with hot
alcohol and decant the boiling solution into the heated
cartridge until the beaker is nearly empty.
A.2.4.3 Wash the remaining solution and the insoluble
is the mass, in grams, of the test portion;
matter into the cartridge, using a “policeman ”, if necessary,
with successive portions of hot alcohol contained in a is the mass, in grams, of the residue.
---------------------- Page: 9 ----------------------
IS0 55-l 977 .(E)
A.3.2.3 Flask, of any convenient size.
A.3 METHOD II
A.3.1 Reagent
A.3.2.4 Filter paper, 125 mm in diameter, medium
grade*).
Alcohol : 95 % (V/V) ethanol, or 95 % (V/V) denatured
spirit.
A.3.2.5 Weighing bottles, of glass, approximately 80 mm
in height and approximately 40 mm in diameter, with
A.3.2 Apparatus’ )
ground glass stoppers.
The apparatus consists of siphon tube, adaptor, condenser
and flask, assembled with the aid of corks or ground glass
A.3.2.6 Beaker, 100 ml capacity.
joints so that the solvent can be kept boiling in the flask
and its vapour pass upwards by way of the adaptor to the
A.3.2.7 Drying oven, maintained at 100 + 2 “C.
condenser. The refluxing solvent runs from the condenser
into the cup of the siphon tube.
A.3.2.8 Desiccator, containing sulphuric acid, p 1,84 g/ml,
as desiccant.
A.3.2.1 Siphon tube, of glass, of the type shown in
figure 3, having approximate internal dimensions of 52 mm
A.3.2.9 Balance.
in height and 32 mm in diameter, resting in an adaptor tube
in such a way that the siphon tube is surrounded by the
ascending vapours of the boiling solvent (see figure 3).
A.3.2.10 Gas burner, low form, adjustable, Bunsen type,
carrying a draught shield, or any other suitable heating
device.
A.3.2.2 Condenser, of any convenient pattern.
Dimensions in mill imetres
All dimensions are approx i mate
F
...
INTERNATIONAL STANDARD @ 55
'*Xe
INTERNATIONAL ORGANIZATION FOR STANDARDIZATION -METJlYHAPOJlHAR OPrAHM3AUMR no CTAHAAPTII3AUMM .ORGANISATION INTERNATIONALE DE NORMALISATION
L Seedlac - Specification
Gomme laque en grains - Spécification
First edition - 1977-1 1-01
w UDC 668.447.31 Ref. No. IS0 55-1977 (E)
-
h
pi
Descripton : shellac, materials specifications, tests, chemical tests, sampling.
y
LD
m
w
Price based on 13 pages
---------------------- Page: 1 ----------------------
FOREWORD
IS0 (the International Organization for Standardization) is a worldwide federation
(IS0 member bodies). The work of developing
of national standards institutes
International Standards is carried out through IS0 technical committees. Every
member body interested in a subject for which a technical committee has been set
up has the right to be represented on that committee. International organizations,
governmental and non-governmental, in liaison with ISO, also take part in the work.
Draft International Standards adopted by the technical committees are circulated
to the member bodies for approval before their acceptance as International
Standards by the IS0 Council.
International Standard IS0 55 was developed by Technical Committee ISO/TC 50,
Lac, and was circulated to the member bodies in February 1976.
It has been approved by the member bodies of the following countries
Austria Mexico Thailand
Czechoslova kia Netherlands Turkey
Egypt, Arab Rep. of Romania United Kingdom
India Sweden
No member body expressed disapproval of the document.
This International Standard cancels and replaces IS0 Recommendation R 55-1957,
of which it constitutes a technical revision.
Acknowledgement is due for the assistance that has been derived from the specifi-
cations and publications of the American Society for Testing and Materials, the
American Bleached Shellac Manufacturer’s Association, the United States Shellac
Importer’s Association, the British Standards Institution, the Agricultural Marketing
Adviser to the Government of India, Messrs. Angelo Brothers, Ltd., Calcutta, and
the Indian Lac Research Institute. Considerable assistance has been derived also
from A Handbook of Shellac Analysis, by M. Rangaswami and H. K. Sen, issued
bv the Indian Lac Research Institute.
O International Organization for Standardization, 1977 0
Printed in Switzerland
II
---------------------- Page: 2 ----------------------
CONTENTS Page
O Introduction . 1
1 Scope and field of application . 1
2 Definitions . 1
3 Form and condition . 1
4 Grades . 2
5 Mandatory requirement . 2
6 Optional requirements . 2
7 Sampling . 2
Annexes
A Determination of matter insoluble in hot alcohol . 3
B Determination of volatile matter (moisture) . 8
C Determination of colour index . 9
D Determination of matter soluble in water and of neutrality of
aqueous extract . 1 0
E Determination of wax content . 11
F Sampling . 12
...
III
---------------------- Page: 3 ----------------------
INTERNATIONAL STANDARD IS0 55-1977 (E)
Seed lac - Specification
O INTRODUCTION 0.6 For the purpose of deciding whether a particular
requirement of this International Standard is complied
0.1 The usual trade descriptions of seedlac are based on
with, it is necessary for the final value, observed or calcu-
the Indian names of the host trees, the season of cropping
lated, expressing the result of test or analysis to be rounded
the sticklac, visual differences or a combination of any
off to the same number of places as that in the specified
of these. The use of these grade designations led to con-
value, it being always understood that the analyst will
fusion and some marketing difficulties. When ISO/R 55
carry out his determination to at least one place more than
was prepared in 1957, it was decided to adopt only seven
in the specified value.
grades which were independent of the names of host trees
or seasons. However, the expectation that the IS0 grades
1 SCOPE AND FIELD OF APPLICATION
for seedlac would be increasingly adopted in trade and
ultimately replace the traditional grade designations has
1.1 This International Standard specifies requirements
not come about. A new system has thelefore been adopted
and methods of test for seedlac.
in this International Standard so that seedlac can now be
completely identified by a combination of the IS0 grade
1.2 This International Standard is intended chiefly to
and the trade grade. In this revision, it has been found
cover the technical provisions for guiding the purchase of
possible to reduce the number of IS0 grades from seven
all the necessary prc-
the material, but does not include
to five.
visions of a contract.
0.2 For matter insoluble in hot alcohol, two limits are
1.3 The limits specified in this International Standard are
prescribed, in line with trade practice : a basic limit and a
limits for rejection (see 0.2).
relaxed limit. The relaxed limit shall be the limit for
rejection.
2 DEFINITIONS
0.3 The requirement for non-volatile matter soluble in
For the purposes of this International Standard, the follow-
cold alcohol has not been retained as this requirement is
ing definitions apply :
applied in practice to waste products of lac only.
2.1 sticklac : The natural product of lac insects.
0.4 One of the requirements for seedlac, namely that for
matter insoluble in hot alcohol, is included in this Inter-
2.2 seedlac : The product obtained by washing crushed
national Standard as an essential clause. The remainder,
sticklac.
namely those for volatile matter (moisture), colour, bleach
index and bleachability, matter soluble in water, wax and
ash, are optional. 2.3 approved sample : The sample agreed upon between
the purchaser and the vendor as the standard for coiour
and appearance.
0.5 For determination of bleach index and bleachability,
two methods are practised. One has been developed in India
and the other in the U.S.A. The method to be followed for
3 FORM AND CONDITION
the determination of bleach index and bleachability shall be
The form and condition of seedlac are subject to agreement
subject to agreement between the purchaser and the
between the purchaser and the supplier.
supplier.
1
---------------------- Page: 4 ----------------------
IS0 55-1977 (E)
6 OPTIONAL REQUIREMENTS
4 GRADES
Five grades of seedlac, namely Special, A, 6, C and D are
6.1 Volatile matter (moisture)
specified. Further, if required by the purchaser, the names
of the grades as prevalent in trade shall be indicated in
Seedlac shall not contain more than 2.5 % (rn/rn) of volatile
addition, in parentheses, as shown below :
matter (moisture) as determined by the method described
in annex B.
- Grade Special (Golden Kusmi);
- Grade B (Kusmi No. 2). 6.2 Colour index
The colour index of seedlac, as determined by the method
The correspondence between IS0 grades and trade grades
described in annex C, shall not exceed the limits given in
is shown in table 1.
table 3.
TABLE 3
TABLE 1
Colour index
Grade
Trade grade
IS0 grade
(maximum)
1 I
i) Golden Kusmi
Special 8
Special
ii) Golden Bysacki
A 10
iii) Grade I, Class A
B 12
18
C
A i) Kusmi No. 1
D 30
ii) Grade II, Class A
B i) Kusmi No. 2
Alternatively, the appearance and colour of seedlac shall
ii) Manbhurn Fine Bysacki
not be inferior to those of an approved sample when judged
by visual examination.
iii) Grade I, Class B
I-- 1 il Fine Bysacki
6.3 Bleach index and bleachability
ii) Grade II, Class B
The bleach index of seedlac shall be determined or the
D i) Ordinary Bysacki
bleachability test for seedlac shall be carried out, if either
is agreed between the purchaser and the supplier, in ac-
cordance with such methods as may be agreed between
them (see 0.5).
5 MANDATORY REQUIREMENT
6.4 Matter soluble in water
Matter insoluble in hot alcohol
Seedlac shall not contain more than 1 % (rn/rn) of matter
soluble in water, and the aqueous extract shall be neutral
Seedlac shall not contain more than the basic limits of
to methyl .red. Matter soluble in water shall be determined
matter insoluble in hot alcohol specified in table 2, when
by the method described in annex D.
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
6.5 Ash
limit may be relaxed but it shall not in any case exceed the
relaxed limit as shown in table 2. The limits and methods of test for ash content of seedlac
shall be subject to agreement between the purchaser and
the supplier.
m
6.6 Wax
Basic limit Relaxed limit
Grade
% imh) % imlm)
Seedlac shall not contain more than 5,5 % (rn/rn) of wax
when determined by the method described in annex E.
Special 2,o 3.0
A 3.0 4.0
B 3.0 4.0
C 3.0 5.0
7 SAMPLING
D 5.0 7 .O
Samples shall be taken in the manner described in annex F.
-
2
---------------------- Page: 5 ----------------------
IS0 55-1977 (E)
ANNEX A
(See clause 5)
DETERMINATION OF MATTER INSOLUBLE IN HOT ALCOHOL
A.l PRINCIPLE A.2.2 Apparatus
The matter insoluble in hot alcohol is determined by
A.2.2.1 Condenser, all glass, of the type and dimensions
extracting a known mass of seedlac with 95 % (V/V) ethanol
shown in figure 1, with the tip cut at an angle of 45O. The
and determining the percentage of the undissolved residue
condenser shall have two holes in its tip to hold the siphon
by either of the two methods described below, as may be
tube (A.2.2.2).
agreed.
A.2 METHODI
A.2.2.2 Siphon tube, of glass, of the type and dimensions
shown in figure 1. The siphon tube shall have two holes
A.2.1 Reagent
near the top for a wire to be fastened to the condenser tip,
leaving about 6 mm space between the top of the tube and
Alcohol : 95 % (V/V) ethanol, or 95 % (V/V) denatured
L
spirit. the condenser tip.
Dimensions in millimetres
All dimensions are approximate
@ int. 32 f 0.5.
@ int. 3 to 3,5
Siphon tube
int.' I I f I
Condenser Filter tube
FIGURE 1 - Extraction apparatus for determining matter insoluble in hot alcohol - Method I
3
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IS0 55-1977 (E)
A.2.2.3 Conical flask, heat-resistant, wide-mouthed, prefer- A.2.2.5 Extraction cartridges, of fat-free paper, approxi-
mately 25 mm in diameter and approximately 60 mm in
abiy of borosilicate glass, approximately 175 mm in height
height.
and approximately 50 mm in inside diameter at the top.
A.2.2.6 Weighing bottle, glass-stoppered, approxi-
The flask shall be fitted with a tight-fitting cork 25 mm in
mately 80 mm in height and approximately 40 mm in
depth and bored to fit the stem of the condenser. The
diameter.
bottom of the cork shall be just above the holes for the
wire in the condenser. To support the flask, a suitable ring
A.2.2.7 Hot water bath, made of about 0,9 rnm thick
support with iron clamp and nickel-chromium or iron
copper or stainless steel, having a width of approxi-
gauze shall be used. The gauze shall not have asbestos
mately 1 O0 mm and other dimensions as given in figure 2.
covering.
The cover shall have a flanged hole, 57 f 1 mm in diameter,
for a 200 ml beaker, and also a hole 35 2 1 mm in diameter
through which the top of the filter tube projects. Directly
A.2.2.4 Carbon filter tube, of the type and dimensions below this hole, in the bottom of the bath, there shall be
shown in figure 1, with a light spiral spring at the bottom
a flanged hole, 25 f 1 mm in diameter, to hold the rubber
to hold up the extraction cartridge. The stem of the filter stopper, through which the stem of the filter tube extends,
a rubber stopper and shall be
tube shall be fitted with to discharge into the bottle or flask. The hot water bath
~~
firmly supported in a hot water bath.
shall be mounted on a low tripod or stand.
Dimensions in millimetres
All dimensions are approximate
300
4
.
@ ext. 32 -I 1
1-t-I-
,
I
Rubber stopper
FIGURE 2 - Hot water bath for insoluble matter test - Method I
4
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IS0 55-1977 (E)
wash-bottle kept hot on the water bath. Finally, wash the
A.2.2.8 Beaker, tall-form, 200 ml capacity.
cartridge from the top downwards with a fine stream of
hot alcohol. A complete washing and transfer from the
A.2.2.9 Desiccator, containing sulphuric acid, p 1.84 g/ml,
original beaker will require at least 75 ml of hot alcohol.
as desiccant.
A.2.2.10 Drying oven, maintained at 1 O0 ? 2 OC. A.2.4.4 Transfer the cartridge containing the insoluble
matter to the extraction apparatus, place 125 ml of alcohol
in the extraction flask and connect up the apparatus. Start
A.2.2.11 Weighing balance, accurate to 0,l mg.
the water flowing through the condenser, making sure that
is an adequate supply for efficient condensation.
there
A.2.2.12 Gas burner, low form, adjustable, Bunsen type,
Light the burner and time the extraction from the first
carrying a draught shield, or any other suitable heating
emptying of the siphon, running the extraction for exactly
device.
1 h. Adjust the rate of heating so that a complete filling
and emptying of the siphon tube takes place every 2 min, as
determined by a stop:watch or preferably by a good two^
A.2.3 Preparation of extraction cartridge
minute sand-glass, one for each extraction apparatus.
A.2.3.1 Place 125 ml of the alcohol (A.2.1) in the
A.2.4.4.1 In this way exactly 30 cycles per hour are
flask (A.2.2.3) and a new cartridge (A.2.2.5) in the siphon
L
accomplished. If this cycle rate is not meticulously main-
tube (A.2.2.2). Introduce the siphon tube into the flask and
tained, neither check results on duplicate samples in the
connect it to the condenser (A.2.2.1), making sure that
same laboratory nor concordant figures from one labora-
there is ample flow of cold water through the condenser.
tory to another can be obtained, even when working on the
Adjust the rate of heating SO as to give a cycle of filling and
same standard sample. It is also necessary to protect the
emptying in the siphon tube every 2 min and extract
apparatus from draughts while in operation, otherwise the
for 30 min. Dry the cartridge in the oven (A.2.2.10)
proper cycle rate cannot be maintained.
at 100 2 2 OC. At the end of 2 h, weigh it in a tared
weighing bottle (A.2.2.6). which has been kept in the
desiccator over sulphuric acid (A.2.2.9), lifting the stopper
A.2.4.4.2 Occasionally, seedlacs are encountered which do
of the bottle momentarily before weighing. Repeat the
not yield the required number of 30 siphonings per hour,
operations of drying, for periods of 1 h, and weighing,
due to slow filtration, in these cases, continue the ex-
until the loss in mass between two successive weighings
traction until 30 siphonings have been accomplished 01
does not exceed 2 mg.
repeat the test with a 2 g test portion and report the sample
as abnormal or slow filtering.
A.2.3.2 Use only new cartridges. A number of cartridges
may be extracted, dried, weighed and kept in weighing
A.2.4.5 Remove the cartridge, drain in an upright position
bottles in a desiccator until needed for use.
on filter paper and dry in the oven at 100 2 2 OC. After
drying for 2 h, place it in the weighing bottle, cool in the
desiccator over sulphuric acid and weigh, removing tbe
A.2.4 Procedure
stopper momentarily just before weighing. Repeat the
operations of drying, for periods of 1 h, and weighing,
A.2.4.1 Before analysis, thoroughly mix the test sample until the loss in mass between two successive weighings
(see F.3.1) by rolling on paper, at least ten times, to ensure does not exceed 2 mg. From the mass of the residue and
uniformity of the test sample. Weigh, directly from the the mass of the sample, calculate the percentage of in-
paper, 4.5 to 5,5 g of the sample, to an accuracy of 0.01 g, soluble matter. Use the lowest mass in the caiculation.
place in the beaker (A.2.2.8), add 125 ml of the alcohol
(A.2.1), cover with a watch-glass and place on the hot water
bath (A.2.2.7) (see figure 2). Boil the solution vigorously
for 30 min to ensure complete solution of the seedlac and
A.2.5 Calculation
dispersion of wax. Keep the volume of alcohol constant by
The matter insoluble in hot alcohol, expressed as a per-
adding hot alcohol from a wash bottle, washing down the
centage by mass, is given by the formula
sides of the beaker.
A.2.4.2 Meanwhile, place an extracted and weighed
IOOrn,
cartridge in the filter tube. Maintain the hot water around
the tube at not less than 90 OC. Wet the cartridge with hot
alcohol and decant the boiling solution into the heated
cartridge until the beaker is nearly empty.
where
A.2.4.3 Wash the remaining solution and the insoluble
rn, is the mass, in grams, of the test portion;
matter into the cartridge, using a "policeman", if necessary,
with successive portions of hot alcohol contained in a
rn2 is the mass, in grams, of the residue.
5
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IS0 55-1977 (E)
A.3.2.3 Flask, of any convenient size.
A.3 METHOD II
A.3.1 Reagent
A.3.2.4 Filter paper, 125 mm in diameter, medium
gradez).
Alcohol : 95 % (V/V) ethanol, or 95 %, (V/V) denatured
spirit.
A.3.2.5 Weighing bottles, of glass, approximately 80 mm
in height and approximately 40 mm in diameter, with
A.3.2 Apparatus' )
ground glass stoppers.
The apparatus consists of siphon tube, adaptor, condenser
and flask, assembled with the aid of corks or ground glass
A.3.2.6 Beaker, 1 O0 ml capacity
joints so that the solvent can be kept boiling in the flask
and its vapour pass upwards by way of the adaptor to the
A.3.2.7 Drying oven, maintained at 100 t 2 "C
condenser. The refluxing solvent runs from the condenser
into the cup of the siphon tube.
A.3.2.8 Desiccator, containing sulphuric acid, p 1.84 g/ml,
as desiccant.
A.3.2.1 Siphon tube, of glass, of the type shown in
figure 3, having approximate internal dimensions of 52 mm
A.3.2.9 Balance.
in height and 32 mm in diameter, resting in an adaptor tube
in such a way that the siphon tube is surrounded by the
ascending vapours of the boiling solvent (see figure 3).
A.3.2.10 Gas burner, low form, adjustable, Bunsen type,
carrying a draught shield, or any other suitable heating
device.
A.3.2.2 Condenser, of any convenient pattern.
Dimension
...
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