MVT TEST OF 0.010" THINCK KEL-F FILM W.O.944

• Document Type: CREST
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP78-03642A001600020126-3
• Release Decision: RIPPUB
• Original Classification: S
• Document Page Count: 2
• Document Creation Date: December 27, 2016
• Document Release Date: November 7, 2012
• Sequence Number: 126
• Publication Date: October 26, 1955
• Content Type: REPORT

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Declassified in Part - Sanitized Copy Approved for Release 2012/11/07: CIA-RDP78-03642A001600020126-3
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26 October 1955
MVT Test of 0.010" Thick
Kel-F Film
Introduction
Kel-F is a tough, chemically resistant plastic which is stated to
have a good resistance to moisture vapor transmission. A sample of
Kel-F was furnished by TSS/ED to get a measure of the transmission
rate. Results of this test are given in the memorandum.
Summary
1. MVT test showed transmission of 14.1 mg a day of water vapor
through 1 sq. ft. of Kel F-sheet 0.010" thick. This corresponds to
transmission of about 5 grams of water vapor per year per sq. ft. for
Ke.i-F sheet of this thickness.
2. Blank determinations were higher than normal but probably
not high enough to indicate an appreciable effect in the rate of trans-
mission. Agreement between the two blanks and between the two test
pieces was good.
3. Further improvement in the pre-drying of the nitrogen gas
will be effected before further MVT tests are run.
Testing equipment such as was described under W. 0. 633 was'used in
this test. Four pieces of Kel-F were cut and one each was cemented
between top and bottom flanges of each of the four test chambers. Area
of the opening in each chamber was 14.1 sq. in., or 0.098 sq. ft.
Water was contained in the bottoms of two of the chambers while
the other were left dry to serve as blanks.
Before testing each sample was dried in a calcium chloride desiccator
for one week.
As usual in each case, a rather high transmission rate was noted
which dropped substantially to its final value in about 10 days.
The test was concluded when a constant rate had been noted for
.both the blanks and the test pieces mounted above water.
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Declassified in Part - Sanitized Copy Approved for Release 2012/11/07: CIA-RDP78-03642A001600020126-3
 Declassified in Part - Sanitized Copy Approved for Release 2012/11/07: CIA-RDP78-03642AO01600020126-3
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The difference between blanks and test pieces ran 1.0 mg. per day
per 14.1 sq. in. or 10.2 mg. per sq. ft. per day. A high blank of
6 mg. per day per 14.1 sq. in. or 61 mg. per sq. ft. per day. However, _.
both blanks and both test pieces checked each other throughout the
final week of the test. On the basis of the rate of sweeping with the
nitrogen gas it was calculated that the gas was less than 10% saturated
so that it is doubtful that the moisture vapor transmission rate was
greatly affected.
For-the above reasons it is believed that the calculated transmis-
sion rates are accurate and representative of the samples tested. How-
ever, it is poor practice-to have so large a blank. Therefore, a
better drying system is being installed in the gas line together with
means for making a better check of the effectiveness of the dryer.
On the basis of this test _0.010" Kel-F compares favorably with the
Mylar-aluminum foil-Mylar laminates tested under W. 0. 633.
Technical Services Laboratory, TSS
Distribution:
Orig. - ED/
TSS/TSL - 1
Cu E T L
25X1
Declassified in Part - Sanitized Copy Approved for Release 2012/11/07: CIA-RDP78-03642AO01600020126-3