1、, 4 MIL-P-25690B W 9999706 l17548b7 T96 I INCH-POUND I MIL-P-256906 29 January 1993 SUPERSEDING MIL-P-25690A 3 August 1960 MILITARY SPECIFICATION PLASTIC, SHEETS AND FORMED PARTS, MODIFIED ACRYLIC BASE, MONOLITHIC, CRACK PROPAGATION RESISTANT This specification is approved for use by all Departments
2、 and Agencies of the Department of Defense. 1. SCOPE ial. 1.1 Scope. This specification covers the requirements for two classes of transparent monolithic, modified, methyl methacrylate flat stretched sheets that may be formed into parts having superior crack propagation and craze resistance as a res
3、ult of proper hot stretching (see 6.4.2). 1.2 Classification. 1.2.1 Classes. Class 1 - Standard moisture resistant stretched mater a 1 ial. Class 2 - Improved moisture resistant stretched mater .2.2 Types. Sheets. Stretched acrylic sheets are specified by thickness (see 3.3.21. Forms. Stretched acry
4、lic formed parts (fabricated assemblies) are specified in the contract or order (see 6.2d). 2. APPLICABLE DOCUMENTS 2.1 Government documents. 2.1.1 Specifications, standards and handbooks. The following specifications and standards form a part of this document to the extent specified herein. Unless
5、otherwise specified, the issues of these documents are those 1 isted in the issue of the Department of Defense Index of Specifications and Standards (DODISS) and supplement thereto, cited in the solicitation (see 6.2h). Beneficial comments (recommendations, additions, deletions) and any pertinent da
6、ta which may be of use in improving this document should be addressed to: Commanding Officer, Naval Air Warfare Center Aircraft Division Lakehurst, Systems Requirements Department, Code SR3, Lakehurst, NJ 08733-5100, by using the self- addressed Standardization Document Improvement Proposal (DD Form
7、 1426) appearing at the end of this document or by letter. I AMSC NIA FSC 9330 DISTRIBUTION STATEMENT A. Approved for public release. Distribution is unlimited. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SPECIFICATIONS FEDERAL A-A-55057 TT-1-735
8、 TT-T-548 TT-W-572 PPP-6-585 PPP-6-591 PPP-B-601 PPP-6-62 1 PPP-6-636 PPP-T-97 MILITARY MIL-P-1 16 MIL-P-81 84 MIL-L-10547 STANDARDS MI LI TARY MIL-STD-105 MI L-STD-129 (Unless otherwise MIL-P-256906 Panels, Wood/Wood Based, Construction and Decorative Isopropyl Alcohol To1 uene, Techni cal Wood-Pre
9、servative, Water-Repellent Box, Wood, W Boxes, Shi pp Boxes, Wood, i rebound i ng, Fi berboard, Wood-C1 eated C Box, Wood, Nai Box, Shipping, Tape, Pressure Reinforced leated Plywood led and Lock Corner Fi berboard Sensitive Adhesive, Filament Preservation, Methods of Plastic Sheet, Acrylic, Modifie
10、d Liner, Case and Sheet, Overwrap, Water Vaporproof or Waterproof, Flexible Sampling Procedures and Tables for Inspection by Attributes Marking for Shipment and Storage indicated, copies of federal and military specifications, and standards are available from the DODSSP - Customer Service, Standardi
11、zation Documents Order Desk, Building 4D, 700 Robbins Avenue, Philadelphia, PA 19111-5094.) “ 2.2 Non-Government pub1 ications. The fol lowing documents form a part of this document to the extent specified herein. Unless otherwise specified, the issues of the documents which are DoD adopted are thos
12、e listed in the issue of the DoDISS cited in the solicitation. Unless otherwise specified, the issues of the documents not listed in the DoDISS are the issues of the documents cited in the solicitation (See 6.2h). 2 Provided by IHSNot for ResaleNo reproduction or networking permitted without license
13、 from IHS-,-,-MIL-P-25690B 9999906 L754839 O21 MI L-P-2569OB AMERICAN SOCIETY FOR TESTING AND MATERIALS (ASTM) O ASTM D637 - Surface Irregularities of Flat Transparent ASTM D638 - Tensile Properties of Plastics ASTM D1003 - Haze and Luminous Transmittance of Transparent ASTM D1718 - Isobutyl Acetate
14、 Plastic Sheets Plastics (Application for copies should be addressed to the American Society for Testing and Materials, 1916 Race Street, Philadelphia, PA 19103.) UNIFORM CLASSIFICATION COMMITTEE, AGENT I Uniform Freight Classification Rules (Application for copies should be addressed to the Uniform
15、 Classification Committee, Room 1106, 222 South Riverside Plaza, Chicago, IL 60606.) (Non-Government standards and other publications are normally available from the organizations that prepare or distribute the documents. These documents may be available in or through 1 ibraries or other information
16、al services.) 2.3 Order of precedence. In the event of a conflict between the text of this document and the references cited herein (except for related associated detail specifications, specification sheets or MS standards), the text of this applicable laws and regulations unless a specific exemptio
17、n has been obtained. 0 document takes precedence. Nothing in this document, however, supersedes 3. REQUIREMENTS 3.1 Qualification. The acrylic material furnished under this specification shall be products which are authorized by the qualifying activity for listing on the applicable Qualified Product
18、s List at the time of award of contract (see 4.3 and 6.3). 3.1.1 First article inspection. The first formed part of a specific configuration produced under a contract or purchase order shall be subjected to fiist article inspection as specified in.4.3.5. 3.2 Materials. The plastic shall be prepared
19、from modified acrylic sheets qualified to Type I, class 1 or Type I, class 2 of MIL-P-8184, except that optical uniformity requirements of the unstretched material may be specified by the purchaser (see 6.2i). The MIL-P-8184 material used to prepare the qualification sample shall be identified to th
20、e Qualifying Laboratory (see 4.3.1.1). 3.2.1 Sheets. The sheets shall be formed by mechanically hot stretching MIL-P-8184 material (see 3.2) using processes that will consistently produce sheets having the properties specified herein. Once produced, the stretched product shall be cut to specific dim
21、ensions as sized flat sheet for direct delivery to the Government or cut into blanks to be further processed into formed parts. 3 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-P-25690B 9999906 I175qBqO 8q3 MI L-P-256908 3.2.2 Formed parts. Part
22、s shall be formed from cut blanks by processes that consistently produce items meeting the requirements specified in this document or on the applicable contractual document (see 6.2d). The stretched sheet used to manufacture the parts shall be identified to the contracting activity. 3.3 Di mens ions
23、 and to1 erances . 3.3.1 Surface dimensions. Dimensions and tolerances of sheets parts shall be as specified in the applicable drawings, specificat purchase orders (see 6.2). When to1 erances are not spec if ied for sheets or formed parts being delivered directly to the Government fol lowing shall a
24、pply: A tolerance of k0.062 inch will be permitted for length and width when the maximum dimension is 40 inches or less. A tolerance of k0.125 inch will be permitted for length and width when the maximum dimension is greater than 40 inches, 3.3.2 Thickness. The thickness of the sized flat sheet or f
25、ormed part shall be as specified in the applicable contractual document. The actual thickness of sized flat sheet intended for direct delivery to the Government, at any point, shall be the nominal thickness i10 percent for thicknesses of 0,250 inch and above, and *O.OZ0 inch for all thicknesses belo
26、w 0.250 inch. The thickness. tolerance for formed parts shall be as specified by the acquisition activity (see 6.2). 3.4 Color. Unless otherwise specified by the acquisition activity, the material shall not contain any added pigments or dyes (See 6.2e). 3.5 Optical uniformity. 3.5.1 Minor optical de
27、fects. The total number of minor optical defects shall not be more than 1 per square foot. Minor defects incl ude any imbedded particles, bubbles or scratches which reduce vi si bi 1 i ty through the plastic, and those localized imperfections which cause a variation in angular deviation of more than
28、 5 minutes within a di stance of not more than 20 inches on the screen when tested as specified in 4.6.3. It is not intended that the entire sheet be quantitatively surveyed for such variation in deviation but that . localized imperfections which are suspected of being detrimental be evaluated by me
29、ans of this test. Blemishes which do not individually reduce visibility through the plastic shall be disregarded (not subject to angular deviation) unless they are grouped in a pattern which appears to affect deviation. Minor defects within 2 inches from the nominal trimmed flat sheet shall be disre
30、garded. Acceptance of minor defects adjacent to the trimmed edge of formed parts shall be as specified by the acquisition activity (see 6.2i). 3.5.2 Angular deviation. Unless otherwise specified by the acquisition activity, the material shall contain no major defect. Major defects shall be any varia
31、tions in the material which cause angular deviations either side of the undeviated position in excess of the limits specified in table I. Angular deviation of formed parts shall be in accordance with the requirements stated on the applicable drawings. 4 or formed sized flat ions, or the Provided by
32、IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-P-256906 3.5.3 Optical distortion. Unless otherwise specified by the acquisition in a sheet or formed part shall not exceed 14 minutes of arc over any 6 inch distance on the surface of the transparency. activit
33、y, the optical distortion limits (rate of change of angular deviation) 3.5.4 Luminous transmittance and haze. The luminous transmittance and haze of colorless material before and after weathering shall be as specified in table II when tested in accordance with 4.6.4 and 4.6.11.3. 3.6 Long term water
34、 absorption. When tested as specified in 4.6.5, Class 2 materials shall not absorb more than 2.90 percent water. TABLE I. Anqular deviation requirement. Sheet thickness 0.060 inch through 0.220 inch Over 0.220 inch through 0.250 Over 0.250 inch through 0.375 nch nch Over 0.375 inch through 0.675 inc
35、h Over 0.675 inch through 1.000 inch Over 1.000 inch Limits of permissible deviation I/ 7 minutes at any location more than 2 inch from the edge of the sheet 7 minutes at any location more than 3 inches from the edge of the sheet and 9 minutes between 3 inches and 2 inches of the edge 7 minutes at a
36、ny location more than 3 inches from the edge and 12 minutes between 3 inches and 2 inches of the edge 7 minutes at any location more than 3 inches from the edge and 14 minutes between 3 inches and 2 inches of the edge 12 minutes at any location more than 3 inches from the edge and 20 minutes between
37、 3 inches and 2 inches of the edge 20 minutes at any location more than 3 inches from the edge and 25 minutes between 3 inches and 2 inches of the edge 5 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-P-25bqOB D 99999Ob L754842 bLb , MI L-P-2569
38、06 TABLE II. Luminous transmittance and haze. Characteristic Luminous transmittance percent min: thickness, inch 0.060 through 0.220 over 0.220 through 0.250 over 0.250 through 0.375 over 0.375 through 0.675 over 0.675 through 1.000 over 1 .O00 Haze, percent, max Condi tion of specimen paragraph 4s
39、recd I after natural weathering Test I 4.6.4 91 90 90 89 88 88 89 88 88 87 86 85 3 I 4 1 4.6.4 3.7 Craze resistance. Stress to craze values when tested as specified in 4.6.10 shall be as follows: Isopropanol ToluenelIsobutylacetate (TT-1-735) (TT-T-548/ASTM 01718) Dry Wet Dry Wet Class 1, psi, min 3
40、000 2000 2500 1750 Class 2, psi, min 3000 2500 2500 2000 3.8 Physical properties. Physical properties shall be as specified in Table III. 3.9 Resistance to natural weatherinq. After testing as specified in 4.6.11 the plastic material shall conform to the after weathering requirements for dimensional
41、 stability (Table III), luminous transmittance and haze (Table II) and crack propagation resistance (Table III). 3.10 Identification of product (see 6.2j). 3.10.1 Markinq of individual sheets. Each stretched sheet shall be identified by using procedures and materials not detrimental to the physical
42、strength or optical requirements of this plastic and that will ensure legibility during the life of the sheet under all environmental conditions. The location of the identification marking on the sheet shall be as specified by the acquisition activity. Unless otherwise specified, identification mark
43、ing shall consist of the following: ABC-XXXXX-1234-05-6-7-256908 where: ABC = Processors initial 1234 = Processors serial number under which complete records of the item are kept xxxxx = Processors Cage No. 05-6-7 = Month, day, and year of stretching 256908 = Specification number 6 Provided by IHSNo
44、t for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-P-25690B TABLE III. Physical properties. Characteristic Resistance to crack propagation, Pounds per inch 32, min, K value Received P std conditions As received -17.8“C (0F) After weathering std conditions Thermal re
45、laxation, shrinkback 110C (230F), %, max P 145C (293F). %, min Tensile strength, psi, min Shear strength, psi , min Dimensional stabi 1 i ty, after natural weathering, %, max. Requ Individual Value 2 300 1150 2100 10.0 37.5 0.2 -emen t Average Value 2 700 1250 2 300 1 1 O00 3000 Test para 4.6.6 4.6.
46、7 4.6.8 4.6.9 4.6.11.2 3.10.2 Marking of fabricated assemblies. When no marking is specified, each fabricated assembly shall be permanently marked with the following information so as to be legible for the anticipated life of the part. The acquisition activity shall specify location and method of ma
47、rking to ensure visibility after installation. The marking shall be not longer than 2 inches when 2 lines are used, and no longer than 4 inches when single or staggered lines are used. Such as: 40-9677-3 256908 24674 05-92 xxxx xxxxx where: 40-9677-3 = The acquisition activity assembly number 25690B
48、 = Specification number 05-92 = Month and year of final fabrication assembly XXXX = The manufacturers trade mark or initial 24674 = The manufacturers serial number (example) XXXXX = The manufacturers Cage No. 3.10.3 Marking letter size limitations. Unless otherwise specified (see 6.2j), maximum mark
49、ing letter height shall be 0.125 inch. Spacing between lines of letters shall not be greater than 0.0625 inch, and the methods used for marking shall not cause distortion of the plastic surface beyond 0.125 0 inches from the edges of the markings. 7 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-flIL-P-2569QB m 999990b 1754844 499 m MIL-P-25690B 3.11 Instruction sheet for flat
