1、!Y I . 71 MTLIT ARY SPEC IFIC AT ION 4 November 1968 COBTIN, POLYUEETHAIDi, FOR PROTECTION OF * INTEGRAL FIEL, TANK SEALING COMPOUND 1. SCPPE 1.1 This specification covers a coating material to be applied over aircraft integral fuel tank sealing compound for protection against fuel and fuel contamin
2、ants. , .2b PLIc s 2.1 The following specifications and standards of the issue in effect on date of invitation for bid form a part of this specification to the - extent specified herein. SPEC IF IC AT IONS Federal QQ-A-250/12 QQ-A-250/13 QQ-S-698 TT-s-735 TT-T-548 ccc-c-419 FPi“B-636 PPP-C-96 Milita
3、ry 1 MIGC-55LJ MIL-S-7502 xluminum Alloy 7075, Plate and $beet Aluminum Alloy Alclad 7075, Plate and Sheet Steel, Sheet and Strip, Low-Carbon Standard Test Fluids, Hydrocarbon Toluene, Technical Cloth, Duck, Cotton, Unbleached, Ylied-Yarns, Box, Fiberboard Can, Metal,28 Gage and Lighter Army and Num
4、bered Chemical Films and Chemical Film Materials for bluminum and tiluminum Alloys Sealing Compound, Integral Fuel Tanks and Required Cell Cavities, High Adhesfon, Accelerator fl . . THIS DOCUMENT CONTAINS /3 PAGES. L Y Provided by IHSNot for ResaleNo reproduction or networking permitted without lic
5、ense from IHS-,-,-%ILS-8802 Sealing Compound, Temperat.ure-Kcsistiant, Integral Fuel Tanks and Fuel Cell Cavities , High adhesion aircraft Integral Fuel Tanks Ivlaterials in Cemkits Integral Fuel Tanks EIGC-27725( USU) Coating, Corrosion Preventive, For EIG?-38714( USW) Packaging and Fackirig of Two
6、 Component xItc-3ii736( ?%IF) Cleaning Compound , Solvent, For Use in STAEDAILDS Fe6 Test Method Faint, Varnish, Lacquer, and Related St6 KO. 14l. Naterials, Nethods of Inspection, Sampltng, and Testing Fee! Tect Nethoc! Lubricants, Liquid Fuels, and ilelated 3td Kc. 791 Froducts, Methods of Testing
7、 Mil it arv Wi Bullet in I?o. 535 bhrking for Shipment and Storage Sampling Procedures and Tables for Inspection by attributes Free Diisocyanate Test Method (Copies of specifications, standards, drawings, and publications reqaired by sugpli.ers ln cornection with specific procuremer,t iuncti0n.s sho
8、uld be obtained from the procuring activity or as directed by the contracting officer. ) 2.2 Other publicationg. The following documents form a pzrt of this specificat.icn to the extent specified herein. Gnless otherwise tndicated, the issue in effect on the date of invitation for bids or request fo
9、r proposai shall apply: AXi3RTSAK SCCTL?Y L“32 TZST3iG AND MATGLIALS 1323 Test. for Kercaptan Sulfur in 4viatin Turbine Fuels (Amperometric and Potentiometric Iathods) BMS 10-39 Fuel an4 Moisture Resistant Finish for Fuel Tanks 2 Provided by IHSNot for ResaleNo reproduction or networking permitted w
10、ithout license from IHS-,-,- . - _ “. . -. . “ . . - “;T MIL-C-83019 80 9799906 0331025 b 9 3.1 Preproduction tests. The coating material furnished mder this speclfication shall be a product which has met the preproductlon tests specified herein. If there are any changes in materials or manufacturin
11、g processes, new preproduction tests are required. 3.2 Xaterials. The coating material shall be a 2-part polyurethane type formulated from a chemlcally curing composition of such ingredients as may be necessary to produce a product of high quality which will meet the requirements of thip specificati
12、on. The coating material shall ke transparent or translucent, 3,2.1 Appearance. he material shall be a uniform compow.2 free of skins, lumps, a2d gelled or coarse particles. There shall be no separation of ingredients which cannot be readily re-dispersed. -3.2.2 The product formulation and toxicolog
13、ical data available, particularly as related to the intended applicatlon, shall be submitted by the supplier f3r revlew by competent military medical authorities who will detsrmine whet.her the available infornation is sufficient to clearly establish the aafeky of the material for the proposed use.
14、If the data submitted is not considered sufficient , additional information deemed necessary to determne suitability of the product shall be furnished. -. 3.3 Frepert.ies. Properties of the coating material shall be in accerdance with the requirements of table I. Table I. Properties and requSrements
15、 Property . Requirement Test Method Nonvolatile Content viscosity Application Life Tack-free-t Ise Cure time 15 to 22 seconds 4.7.5 Viscosity Measurement 4.7.3 30 seconds, Maxinm, at 3 hours 4 hours, kxirnm 4 -7 04 Substrate shall not be exposed 4.7.5 after 48 hour cure I Provided by IHSNot for Resa
16、leNo reproduction or networking permitted without license from IHS-,-,-Ziesist snce to Szlt wster ancl fuel Coating Coxpatibtlity ound 1 1 . 5% Maximum Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-4.1 ;3esponsibilits for inscection. Unless otherwi
17、se specified ir, the contract or purchase order, the supplier is responsible for the perfomance af all inspectron requirements as specified herein. Except as .ot. LhleFs otherwise specified, a lot -hall consist of all coati.ng material manufactured at one ti-me from one batch, forming Frt of one con
18、tract or order for delivery. “ , - 5 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-a. Xonvolatile content b. Viscoa?ty c. Bpplicatfon l-ife d. Tack-free time e. Cwe time f . Sealing com-,crund protection, wefght loss ( KL?-7502 only) 4.4.3 ,+.iecti
19、on and retest. When one or more samples of coating material from a lot fail tc meet the specif5.cat.ion, the lot shall be withheld until the extePt and cause of failure have been determined. The contractor shall explain fully to the procuring activity the cause of failure and the action taken to pre
20、clude recurrence. After correction, all of the sampling tests shall be repeated. 4.5 Test corditions 4.5.1 Standard condittons. Standard conditions ahell be considered as bekg a temperature of 77O 5 2OF (25 k 1OC) and a relative humfdity of 50 k 5 percent. All tests shall be conducted as standard co
21、nditions unless otherwise specified. 4.6 fieparation of test specimens 4.6.1 Test Panels. Psnels naed in test methods 4.7.4, 4.7.5, 4.7.6, 4.7.8, and 4.7.11 shall be 7075 T4 clad aluminum conforming to -A-250/13. Panels used in test method 4.7.7 shall be 7075 T6 bare aluminum conforming to !licable
22、test methods. The sealing compound shall be cured 48 hours at standard conditions followed by 24 hours at 14C.O ?1 2CF. 6 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-4.6.4 Frexration of corrosion preventive coating. The components of the material
23、 shall be mixed thoroughly in accordance with the instructions of the manufacturer. Four panels, 7075 T6 aluminum alloy conforroing to Q+L250/12c shall be chemically treated per MILF554l. Two panels shall Se coated utth MILE27725 mating material and two with EblS-lG-39b Type I coating material by sp
24、raying or dipping. Cure shall be 48 hours at standard conditions followed by 24 hours at 12OC 5 2“ F and the.cured thickness shall be approximately 1 mil. 4.6.5 Preparation of sealing comwund protection coatinq. Unless otherwise specified the coating material shall be applied by dipping. For test me
25、thods 4.7.4 +vhroqh 4.7.10 a one-quart metal contaher shall be filled to within approximately 1/2 inch of the top with mixed coating material. The container shall be allowed to remain uncovered and undisturbed for 2 hours at standard conditions before application of the coating material to the appli
26、cable substrates, The coating shall be cured 48 hcurs at standard conditions. 4.6.6 Formdatim of jet reference test fluid. The jet reference fluid required for conducting fluid immersion tests shall be formulated as follows : Toluene (TT-T-5M) 30 volumes Cyclohexane (technical grade) 6G volunes Iso-
27、octane (TT-S-735, type I) 10 volumes Tertiary butyl mercaptan O.Gl5 2 0.0015 weight ITertiary dibutyl disulfide 1 volume percent of other four components The tertiary dibutyl disulfide shall be doctor sweet. 4.6.6.1 Ahen tested for mercaptan ans total sulfur in accordance with ATK Xethod 1323 and F!
28、ethod 5201 of Federal Test Methoc! Stadad No. 791, respectively, the reference fluid shall have the following properties: a. Total sulfur content - 0.400 5 0,005 weight percept k-. Hercaptan sulfur content - 0.0050 k O.OGO5 weight percent. The fluid shodd be stored out of contact with light in conts
29、lners which are inert to the fluid ingredients, (Welded aluminmi, non-galvanfeed welded steel, or glas.: containers are suitable.) If not used within 90 days after blending, the fluid should be retested for mercaptan and total safur content. 7 . Provided by IHSNot for ResaleNo reproduction or networ
30、king permitted without license from IHS-,-,-4.7.1 %EvoIs+ile cmter,t. A2proximately 10 grams of mixed coating es5erlal skall ce trsnsferred as rapidly as possible to each of three CUTS 3 izckes ir! ?iarr.e+,er and 3/4 inch deep, .i fitted cover shall irL?ediatzly te Flsced mer each cup and the weigh
31、t determined acmrately, The cns ac? emers shall be weighed accurately prior to use and substracted frm the gross weichts in order to calcdnte the net sae -?:eights. The covers skill tke je remmec! an? material l;ost.cd at 15P-? for 2.4 WS. The matefial sksll then ce cooled, the covsrs replace5., an?
32、 the weI.gkt detemine? accwstely. The percer,tage c? nonvolatle content shall be calcdatec as follows : - rercentage c? rcz-mlatile content = Final wei:?ht. x 16 Initial weight 4.7.3 Aoplication life. A 1-qusrt metal co!-ltain?r 4mll be filled to wit-hin a?Froximtely 1/L inch of the top wtth mixed c
33、natfng mntviai. The cclntanw ?hall be allowed to remaln uncovered and und? sturbed for 2 hours at st.andard con.i!tions. tit that time one pint of the rrater-ial. shall be removed for prepration of test specimens for paragraphs 4.7.4 though 4*7.1C. The remainder of the material shall be left in the
34、quart container untfl a total or“ 3 hours has elapsed from the tfme of mix. A viscosity test shall be conducted in accordance with Federal Test Method ptsrdard No. 141, Kethoci 4292. 4.7.L Tack-free-+,be. An aluminum test panel measuring O.Ci+C- by 2 3/L+ by 6 inches shall be cleaned and dipcoated w
35、ith the coatlng material. The material .hall be allowed to cure at standard conditions for 4 hgur=. Two l-inch by i,s-ir,;nnce to ?ait water an fuel. Two clad alcminm panel3 T,.C42 by 2 3/4 by 6 inches shall be given a 1/8 t l/bA inch coating of !IIL-3“.pfO.2 sealing cornpound and cured ln accordanc
36、e wth 4.6.3. One pane; .;hall be coated with Lhe sealing compound protect!.on coat,ing; the other panel shall serve as a control. After cure of the coating material, bth ynels shall be inmerse3 in a the other panel shall serve as a control. After cure of the sealing compounc! protection coatlng, the
37、 pnela shall be immersed and examined as the panels in 4.7.6. 4.7.8 Adhesim. Two clad aluminum panels 0.040 by 2 3/4 by 6 inches shall be given a 1/8 2 1/64 inch coating of MTGW802 sealing compound and cured in accordance wlth 4.6.3. After curing, the surface of the sealing compound shall be cleaned
38、 in accordance with 4.6.2. Three brush coats of the sealing compound protection coatlng shall be applied allowing 32 minutes drying for each coat. Then, a fourth coating shall be applied and allowed to dry ror 5 minutes. A strip of cotton duck 2 3/4 by 12 inches conformi-ng to Type TI1 of CCC-C-419
39、shall be placed on each panel leavSng a loose end 6 lnchps in lengtk and a heavy coat of the sealing compound protecti.on coating applied. W.vk out any air buk.bles existing underneath the applied fabric, dry 3C minutes, and apply another heavy brush coat. Cure for 4E hours at standard condition. Im
40、merse the panels in jet reference. fluid 7 days at l;Co +- ZCF. after exposure at lL+CF, the panels shall be cooled in the fluid for i4 hours at standard conditions. The adhesion shall be measured within 30 minutes after removal from the fluid. A 1-inch-wide strip shall Se cct the length of the pane
41、ls through the fatrfc and coating material and into thp KIL-S-88102 sealing corn-mutld to povde the center tnch for the adhesim test. The 7pecimens shall be stripped back at an angle of 1gG depees in a suitable tensile test!ng machjne having a jaw separation rate of 2 inches per minute. The adhesion
42、 shall be measure6 as the pull in FOIX per fnch to separate the coating material from the sealing compound. If a cohesive failure of the coating mater-lal occurs, the value shall not be less than the minimcm adhesive requirement. If a cohesive or adhesive failure of the sealing compound occurs at a
43、value less than the mininmn adhesive requirement, the test shall ke repeated. The results ?hall be the numericel average of the peak loads. 4.7.9 3ealinF conpomc? protect-lon, wekht loss. Flow beets of MIL-P-8802 and XIL-S-75QLi Class 5-2 sealSn,r canpound 1/8 t 1/64 fnch thick shall he pre?,are? -y
44、 presshg between two polyethylene sheets. The top sheet sha3 be removed after 4C hours and the sheet shall be cured in accordance with 4.6.3. 9 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Sight specinens measuri-ng 1 by 2 inches shall be cut from
45、 each flow sheet. rour of each shall be coated by dipping in accorsance with 4.6.5. after the coating has cured, the specimens shall be weighed and the group of fox coated specimens and the group of four uncoated specimens shall each be immersed in 360 cubic centineters of jet reference fluid at UCc
46、 +- LOF. Immersion shall be 14 days of nine fluid changes for the $!ILc-88C2 sealing compounds and 3 days for the MIL-S-7502 sealing ccpc with no fluid change. At the end of the exposure period, the specinens ?hall be removed *om the fluid and air dried for 72 h9u-s at 4OC 2 LCF. The specimens ghall
47、 then be cooled to staneard test, temperature in a-dessicator and weighed. The average pa-?rcent weight loss shall be calculated. The uncoated MIL-.S8802 sealing compound. shall exhibit a weight loss of 5 to 12 percent and the uncoated NTL-S-7502, a weight loss of more than 20 percent. Failure of th
48、e uncoated specimens to show this amount of weight loss shall be cause for investigation and possible repeat of the test. . 4.7.10 Resistance to anti-icing fluid. Four specimens measuring 1 by 2 inches The specimens shall be coated in accordance wiith 4.6.5. after the coating has cured the specimens
49、 shall be immersed in 360 the fluid ant? place them in a flexibility jig at -67O ? ZCF. The flexibilf-ty jg shall consist of a clamp support that will grip both sides of both hall be held at -67O 2 LOF for L hours and then flexed through 13C consecutive cycles. The panels shall be examined for cracking, checking or loss of adhesion. The test shall be repeated if the
