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MIL-PRF-22750 is a two-component, high-solids epoxy coating for spray and brush applications, furnished in a packaged kit and suitable for use under air pollution regulations. This two component epoxy is formulated for the protection against solvents and chemicals on interior and exterior surfaces. It is low “VOC” and lead/chromate free.
This specification covers the requirements for a two component, high solids epoxy coating. This coating is free of all inorganic hazardous air pollutants (HAPS), including compounds of lead and chromium. The coating is supplied as a two-part epoxy kit.
Composition
The coating shall consist of two components, as follows:
Component A – epoxy resin and solvents
Component B – polyamide and/or amine resin(s) and solvents
Component B shall act as the curing agent for component A. The components shall be packaged separately and furnished as a kit. Pigments may be included with either component. When the components are mixed and reduced as specified by the manufacture, a product meeting the applicable requirements of this specification shall result. For class W coating, water may replace all or part of the solvent in component A and/or B.
Classification
The coatings are of the following types, classes and grades
Types : The coating will be furnished in the following types as specified. Whenever one of the following coating types is not cited in a relevant contractual document or drawing, select type I or II for Navy use and type II or III for Army use.
Type I – Standard formulation with a maximum volatile organic compound (VOC) content of 340 grams/liter (g/l) (2.8 pounds/gallon (lbs/gal)) as packaged.
Type II – Volatile organic hazardous air pollutants-free (VOHAP-free) formulation to meet maximum VOC content of 340 g/l (2.8 lbs/gal) as packaged.
Type III – Direct to metal, VOHAP-free formulation to meet maximum VOC content of 340 g/l (2.8 lbs/gal) as packaged. As a direct to metal, this coating will have enhanced corrosion performance including 1,000 hours salt spray and 40 cycles on the cyclic corrosion test. This type is only available in semi-gloss and lusterless colors.
Type IV – Self contained portable kits to include, but not limited to, brush, roller and cartridge application. The kits contain the type II or III epoxy coating.
Classes : The classes of the coating are as follows:
Class H – High solids, solvent base formulation.
Class W – Water base formulation.
Grades. The grades of the coating are as follows:
Grade A – For Navy and Army equipment requiring weather resistance. Grade A approved products can also be used as a grade B material.
Grade B – For the interior of tactical equipment not requiring weather resistance.
Pigments : No component of the coating shall contain lead, cadmium and hexavalent chromium. Compounds of antimony, arsenic, beryllium, cadmium, chromium, cobalt, cyanide, lead, manganese, mercury, nickel and selenium shall also be absent. Pigments contained in these coatings shall be HAPS-free.
Volatile content : The volatile content of the mixed coating shall conform to the following requirements of the volume when tested as specified in 4.7.2 of the specification.
For Type I. The VOC content shall not exceed 340 g/l (2.8 lbs/gal) as packaged
For Types II and III. The VOC content shall not exceed 340 g/l (2.8 lbs/gal) as packaged (see 4.6 and table II). The coatings shall be volatile organic hazardous air pollutants-free (VOHAP-free) when tested in accordance with 4.7.3 of the specification.
Thinner compatibility : The admixed coating shall be compatible with thinner conforming to MIL-T-81772, type II. The resistivity of the solvents shall be suitable for electrostatic spray application.
TYPICAL PROPERTIES:
COLORS………………………. All Fed.Std 595 Colors
SHELF LIFE………………….. 1 Year From Date of Mfg
DRYING TIME:
Set-To-Touch…………………………. Within 1 Hour
Dry Hard……………………………. Within 7 Hours
Thinner…………………………. MIL-T-81772B Ty.II
Gloss Values:
Gloss………………………………….. 90 minimum
Semi-Gloss………………………………… 15 – 30
Camouflage………………………………. 5 maximum
VISCOSITY: (after thinning)
#4 Ford Cup…………. Max 50 seconds(admixed material)
VOLATILE ORGANIC COMPOUNDS:
Max “VOC”………… 340 grams/liter (2.8 pounds/gallon)
Also Known As:
» MIL-C-22750
» QPL-22750
» MIL-PRF-22750
» MIL-PRF-22750A
» MIL-PRF-22750B
» MIL-PRF-22750C
» MIL-PRF-22750D
» MIL-PRF-22750E
» MIL-PRF-22750F
» MIL-PRF-22750G
APPLICATION AND REDUCTION: (SPRAYING)
Each of the two components should be thoroughly mixed separately . Component B is then slowly poured into Component A with constant stirring until a three-to-one ratio by volume is achieved. Reduce the admixed material approximately one pint per gallon with MIL-T-81772B TY.II Thinner to achieve a viscosity of 16-18 seconds in a #4 Ford Cup or for proper atomization. Mix thoroughly and allow to stand one hour before using. Apply a mist coat and allow to dry 30 minutes. Apply a second coat to a total dry film thickness of 1.4 to 1.8 mils. It is normally applied over MIL-PRF-23377G.
The color of the coating is available in a wide variety of colors in the gloss ranges of high gloss, semi-gloss and lusterless. This specification does not limit the suppliable colors, nor does it list all available colors. The coating colors are designated by FED-STD-595.
