|
IS0
I N T ERN AT I O N A L ORGANIZATION FOR STAN DA RD IZATl O N
IS0 RECOMMENDATION
R 699
PULPS
DETERMINATION OF ALKALI RESISTANCE
1 st EDITION
March 1968
COPYRIGHT RESERVED
of IS0 Recommendations and IS0 Standards
The copyright
belongs to IS0 Member Bodies. Reproduction of these
documents, in any country, may be authorized therefore oniy
by the national standards organization of that country, being
a member of ISO.
For each individual country the only valid standard is the national standard of that country.
Printed in Switzerland
Also issued in French and Russian. Copies to be obtained through the national standards organizations.
---------------------- Page: 1 ----------------------
BRIEF HISTORY
The IS0 Recommendation R 699, Pulps - Determination of alkuli resistance, was drawn up by
Technical Committee ISOlTC 6, Paper, board and pulps, the Secretariat of which is held by the Asso-
ciation Française de Normalisation (AFNOR).
Work on this question by the Technical Committee began in 1962 and led, in 1965, to the
i
adoption of a Draft IS0 Recommendation.
In January 1966, this Draft IS0 Recommendation (No. 898) was circulated to all the IS0
Member Bodies for enquiry. It was approved, subject to a few modifications of an editorial nature, by
the following Member Bodies :
South Africa,
Argentina Iran
Australia Rep. of
Israel
Spain
Austria Italy
Belgium Sweden
Japan
Brazil Korea, Rep. of Switzerland
Bulgaria Mexico Turkey
Chile Netherlands U.A.R.
Czechoslovakia New Zealand United Kingdom
Finland Norway U.S.A.
France Poland U.S.S.R.
Germany Portugal Yugoslavia
India Romania
No Member Body opposed the approval of the Draft.
The Draft IS0 Recommendation was then submitted by correspondence to the IS0 Council,
which decided, in March 1968, to accept it as an IS0 RECOMMENDATION.
-2-
---------------------- Page: 2 ----------------------
ISO/R 699-1968 (E
IS0 Recommendation R 699 March 1968
PULPS
DETERMINATION OF ALKALI RESISTANCE
FOREWORD
The scope of both this IS0 Recommendation and of IS0 Recommendation R 692, Pulps - Deter-
of alkali solubility, is to permit the study of the behaviour of pulps in the presence of
mination
alkali solutions, but their fields of application are different : while this IS0 Recommendation describes
the gravimetric determination of the alkali insoluble constituents and applies to all categories of pulp,
IS0 Recommendation R 692 describes the volumetric determination of the alkali soluble constituents
of the pulp and is applicable preferably for the control of bleached pulps.
1. SCOPE
This IS0 Recommendation describes a method for the determination of the alkali - insoluble fraction
of pulp using sodium hydroxide solution of a fxed concentration. The concentrations of sodium
hydroxide most frequently used are 18, 10 and 5
(m/m).
2. FIELD OF APPLICATION
This method is applicable to all kinds of pulp.
3. PRINCIPLE OF THE METHOD
The pulp is defibred under specified conditions in sodium hydroxide solution of the chosen concen-
tration.
The insoluble fraction is filtered off, washed with sodium hydroxide solution of the same concen-
tration and temperature as that used for the processing itself, and is acidified, washed, dried and
weighed.
-3-
---------------------- Page: 3 ----------------------
ISO/R 699-1968 (E
4. DEFINITION OF TERMS
4.1 R-value. Alkali resistance : the insoluble fraction expressed as a percentage of the oven-dry
pulp mass.
4.2 R R R, or Rc. The indices 18, 10, 5 or c refer to the chosen concentration in grammes of
sodium hydroxide per 100 g of solution.
5. REAGENTS
5.1 Sodium hydroxide solution, of known concentration, containing less than 1 g per litre of sodium
carbonate (see Notes below), for example :
- 5.39 M f 0.03 M, containing 18.0 f 0.1 g of NaOH per 100 g of solution
(pZO = 1.1972 g/cm3) equivalent to 215.5 it 1.0 g of NaOH per litre,
- 2.77 M f 0.03 M, containing 10.0 f 0.1 g of NaOH per 100 g of solution
(p2 = 1 .lo89 g/cm3) equivalent to 110.9 f 1 .O g of NaOH per litre,
- 1.31 M t 0.03 M, Containing 5.0 f 0.1 g of NaOH per 100 g of solution
(pZ0 = 1.0538 g/cm3) equivalent to 52.7 f 1.0 g of NaOH per litre.
NOTES
1. Preparation of the sodium hydroxide solution. The sodium hydroxide solution is conveniently prepared as
follows :
Dissolve a quantity of solid sodium hydroxide in an equal mass of distilled water and allow the suspended
sodium carbonate to settle. Decant the supernatant liquid and dilute with carbon dioxide-free distilled water to
appropriate concentration. Check by titration with standard acid.
2. Strength of alkali of maximum dissolving power. Although sodium hydroxide solution generally possesses the
maximum dissolving power at a concentration of about 10 'A, certain pulps show maximum solubility at some
lower or higher alkali concentration. If the R value of an unknown pulp or of a new type of pulp is to be deter-
mined with the sodium hydroxide solution of maximum dissolving power for this pulp, it is necessary to establish
a solubility diagram with several different concentrations in order to find the sodium hydroxide concentration of
maximum dissolving power.
5.2 Acetic acid, 1.7 M, 100 mi of CH,COOH (pZ0 = 1.055 to 1.058 g/cm3) per litre.
6. APPARATUS
6.1 Beaker, of 250 ml, flat bottomed, made of alkali-resistant material.
Stirring rod, of 15 mm diameter with flat end, made of a non-brittle alkali-resistant material,
6.2
preferably hard plastic.
6.3 Filtering device, capacity 80 to 100 ml, with a perforated bottom, inner diameter about 30 mm,
made of alkali-resistant material.
6.4 Stainless steel gauze, to fit the filtering device, pore size about 0.3 mm, soldered along the rim.
Weighing bottle, provided with a lid.
6.5
f 0.2 OC.
Constant temperature bath, capable of maintaining a temperature of 2
...