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Ref. No. : ISO/R 869-1968 (E)
IS0
I NT ERN AT I O N A L O RG AN I Z AT IO N FO R STA N D A RD I Z AT ION
IS0 RECOMMENDATION
R 869
PLASTl CS
PREPARATION OF SPECIMENS
FOR OPTICAL TESTS ON PLASTICS MATERIALS
MOULDING METHOD
1st EDITION
November 1968
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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
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For each individual country the oniy 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.
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ISO/R 869-1968 (E) -
November 1968
I SO R eco m menda t ion R 869
P LAST I CS
PREPARATION OF SPECIMENS
FOR OPTICAL TESTS ON PLASTICS MATERIALS
MOULDING METHOD
1. SCOPE
This IS0 Recommendation describes a method for moulding plastics specimens for optical tests.
NOTE. - The preparation of specimens for optical tests by casting is the subject of IS0 Recommendation R 870, Plastics
Preparation of specimens for optical tests on plastics materinls - Casting method.
2. APPARATUS
The type of mould recommended is shown in the Figure below. It consists of the following parts :
two plates of giass with plane surfaces at least as good as those of photographic plates. A borosilicate glass
(a)
resistant to thermal shock is recommended. The dimensions of the plates should not exceed those of the press
platens;
a stainless steel frame about 4 mm thick;
(b)
two sheets of aluminium about 1 mm thick, placed between the glass plates and the press platens so as to
(c)
distribute the pressure. The insertion of a sheet of firm blotting paper between the glass plates and the
aluminium sheets is recommended.
r/ 'I
Glass plates Stainless steel frame
J
FIGURE - Mould for the preparation of test specimens for optical tests
-2-
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ISO/R 869-1968 (E)
3. PROCEDURE
3.1 After cleaning the plates carefully, assemble the mould as shown in the Figure.
in excess of that needed to produce a test
3.2 Pour the appropriate quantity of the plastics material (about 10
specimen of the required thickness) into the cavity in such fashion that the entire bottom of the cavity is
covered.
Then assemble the mould and place it between the platens of a suitable press; the platens must be plane and
parallel.
3.3 Raise the temperature slowly to that required for the plastics material being moulded and apply the minimum
pressure necessary for such time as is required to produce a sound test specimen.
3.4 Then cool the assembly gradually, under pressure (to avoid the formation of surface irregularities), and open
the mould to remove the sheet of the material.
3.5 It is inadvi
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