Latex Semigloss Exterior Topcoat

Applying Latex Semigloss Exterior Topcoat

PAINT SPECIFICATION NO. 24 – Latex Semigloss Exterior Topcoat

1. Scope
1.1 This specification covers an air drying, ready-mixed, water-borne semigloss latex paint for use on metal surfaces primed with a primer conforming to SSPC-Paint 23. It is intended for use as a topcoat of a water-borne coating system consisting of two coats of primer and one or two coats of this water-borne topcoat.

1.2 This paint is suitable for exposures in Environmental Zones 1A (interior, normally dry) and 1B (exterior, normally dry), and is intended for brush, spray, or roller application over properly primed steel surfaces and is to be applied in accordance with SSPC-PA 1, “Shop, Field, and Maintenance Painting of Steel.” It is not recommended to expose steel to the weather with less than two coats of waterborne coating; therefore, intermediate and topcoats should be applied as soon as possible.

2. Description
2.1 This paint is based on a latex vehicle produced by emulsion polymerization and appropriate pigments. Details of the composition are given in Table 1.
2.2 This paint contains approximately 27% by volume of nonvolatile film-forming solids (pigment and binder). The theoretical spreading rate for a 2.0 mil (51 micrometers) dry film thickness is 215 square feet/U.S. gallon (5.3 square meters/liter). Actual spreading rates can be significantly lower.

3. Referenced Standards
3.1 The latest issue, revision, or amendment of the refer­enced standards in effect on the date of invitation to bid shall govern, unless otherwise specified.
3.2 If there is a conflict between the requirements of any of the cited referenced standards and this specification, the requirements of this specification shall prevail.

3.3 SSPC STANDARDS:

3.4 ASTM INTERNATIONAL STANDARDS:
B 117 Method of Salt Spray (Fog) Testing
D 523 Test Method for Specular Gloss
D 562 Test Method for Consistency of Paints Measuring Krebs Unit (KU) Viscosity Using a Stormer-type Viscometer
D 609 Practice for Preparation of Cold-Rolled Steel Panels for Testing Paint, Varnish,Conversion Coatings, and Related Coating Products
D 610 Test Method for Evaluating Degree of Rusting on Painted Steel Surfaces
D 714 Test Method for Evaluating Degree of Blistering of Paints
D 1210 Test Methods for Fineness of Dispersion of Pigment-Vehicle Systems by Hegman-type Gage
D 1296 Test Method for Odor of Volatile Solvents and Diluents
D 1640 Test Methods for Drying, Curing, or Film Formation of Organic Coatings at Room Temperature
D 1654 Method for Evaluation of Painted or Coated Specimens Subjected to Corrosive Environ­ments
D 1737 (Withdrawn) Elongation of Attached Oranic Coatings with Cylindrical Mandrel Apparatus (Replaced by ASTM D 522)
D 1849 Test Method for Package Stability of Paint
D 2243 Test Method for Freeze-Thaw Resistance of Water-Borne Coatings
D 2244 Method for Calculation of Color Differences from Instrumentally Measured Color Coordinates
D 2247 Practice for Testing Water Resistance of Coatings in 100% Relative Humidity
D 2486 Test Method for Scrub Resistance of Wall Paints
D 2574 Test Method for Resistance of Emulsion Paints in the Container to Attack by Micro­organisms
D 2801 (Withdrawn) Test Method for Leveling Characteristics of Paints by Draw-Down Method
D 3273 Test Method for Resistance to Growth of Mold on the Surface of Interior Coatings in an Environmental Chamber
D 3274 Test Method for Evaluating Degree of Surface Disfigurement of Paint Films by Microbial (Fungal or Algal) Growth or Soil and Dirt Accumulation
D 3891 Standard Practice for Preparation of Glass Panels for Testing Paint, Varnish, Lacquer, and Related Products
D 3925 Practice for Sampling Liquid Paints and Related Pigmented Coatings
D 4400 Test Method for Sag Resistance of Paints Using a Multinotch Applicator Specification for Wire-Cloth and Sieves for Testing Purposes
E 97 (Withdrawn) Test Method for Directional Reflectance Factor, 45-deg 0-deg, of Opaque Specimens by Broad-Band Fil­ter Reflectometry (Replaced by ASTM E 1347)
E 1347 Test Method for Color and Color-Difference Measurement by Tristimulus (Filter) Colo­rimetry
G 23 (Withdrawn) Practice for Operating Light-Exposure Apparatus (Carbon-Arc Type) With and Without Water for Exposure of Nonmetallic Materials (Replaced by ASTM G 152 and G 153)
G 26 (Withdrawn) Practice for Operating Light-Exposure Apparatus (Xenon-Arc Type) With and Without Water for Exposure of Nonmetallic Materials (Replaced by ASTM G 155.)
G 151 Standard Practice for Exposing Non-Metallic Materials in Accelerated Test Devices that Use Laboratory Light Sources

3.5 FEDERAL STANDARDS:
TT-E-506 Enamel, Alkyd, Gloss, Tints and White (for Interior Use)
FED-STD-141 Paint, Varnish, Lacquer and Related Ma­terials: Methods of Inspection, Sampling and Testing
Method 2021 (Canceled) Preparation of Glass Panels (Use ASTM D 3891)
Method 6141.1 (Canceled) Washability

3.6 AMERICAN NATIONAL STANDARDS INSTITUTE (ANSI) STANDARD:

Z129.1 Hazardous Industrial Chemicals— Precautionary Labeling

4. Composition
4.1 The manufacturer is given some latitude in the selec­tion of materials and process of manufacture, provided that the paint meets the requirements of this specification. Materials shall be of the best quality used in good commercial practice and entirely suitable for the purpose intended under normal conditions of use.
4.2 The vehicle shall be a stable dispersion of synthetic resin particles (latex) in water prepared by emulsion polymer­ization, together with the necessary additives such as pigment dispersant, anti-foamer, preservatives, and “antifreeze” in order to produce a paint conforming to this specification. A suitable film and package preservative shall be used.
4.3 The paint shall conform to the composition (analysis) requirements of Table 1.

5. Properties
5.1 The paint shall meet the requirements of Table 2 and Sections 5.2 through 5.17.
5.2 ODOR: Shall be normal for the materials permitted (ASTM D 1296). In a freshly opened container, there shall be no offensive, disagreeable, or putrid odor.
5.3 COLOR: The color shall be as specified in the procure­ment documents.
5.4 RESISTANCE TO MICROORGANISM ATTACK: The paint shall be resistant to attack by microorganisms when tested according to ASTM D 2574.
5.5 APPLICATION PROPERTIES: The paint shall be easily applied to a smooth steel vertical surface at 5 mils (127 micrometers) wet film thickness on 320 square feet/gallon (7.9 square meters/liter) by brush, spray, or roller. Drying shall be done in a well-ventilated room or chamber free from drafts and dust and in diffused light, not in direct sunlight. The temperature of the air shall be between 21 and 28°C. The relative humid­ity shall be 50% ± 5%. There shall be no runs, sags, streaks, flashes, laps, pinholes, fisheyes, or craters. After four hours of drying, apply a second coat in the same manner as the first. There shall be no picking-up or rolling-up of the first coat dur­ing applications. After 24 hours, the film shall be smooth and uniform.
5.6 CONDITION IN CONTAINER: The paint as received shall show no evidence of livering, skinning, or hard settling of the pigment. The inside of the container shall not be corroded. The material shall be easily dispersed in the liquid portion by hand stirring to form a smooth, homogeneous paint. The paint shall show a minimum of foaming and be free of grit, seeds, lumps, or livering.

5.7 FREEZE-THAW RESISTANCE: The paint shall pass three cycles when tested according to the procedure described in ASTM D 2243. There shall be no gelation, or excessive thick­ening, coagulation, lumps, or coarse particles. The maximum allowable increase or decrease in viscosity shall not exceed 10 Kreb units.
5.8 WET ADHESION: Prepare 6 x 17 x 1 /4 inch (15 x 43 x 0.63 cm) glass panels with a ground surface which has been cleaned according to FED-STD-141, Method 2021. Apply alkyd enamel conforming to Federal Specification TT­E-506 drawndown with a suitable applicator obtaining a dry film thickness of 3.0 ± 0.3 mils (76 ± 8 micrometers) and a width of 5-1/2 inch (14 cm). Allow the alkyd enamel to dry in a horizontal position for three days at 74 to 80°F (23 to 27°C) and 50% ± 5% relative humidity. Bake two hours at 200°F (93°C) prior to the application of the test paint. Apply the test paint by drawdown as above in a direction perpendicular to the long axis of the panel to obtain a dry film of 2.0 ± 0.2 mils (51 ± 5 micrometers) and a width of approximately 2 inches (5 cm). Allow the test paint to dry for 48 hours at 74 to 80°F (23 to 27°C) and 50% ± 5% relative humidity.

Make a cut (the entire width of the test panel) perpendicular to the long axis of the glass panel through the center of the test film with a razor blade held at a 45-degree angle. Place the panel on a Gardner Machine (described in FED-STD-141, Method 6141) so that the test paint is approximately in the center of the brush stroke and scrub under water with the brush described in ASTM 2486. A brush shall move in a direction parallel to the long axis of the glass panel and perpendicular to the cut made in the test film. The brush shall travel at a rate of 39 ± 1 cycles (78 ± 2 separate strokes) per minute. There shall be no adhesion failure between the test paint and alkyd undercoat after 800 strokes. The paint may wear through to the alkyd enamel in less than 800 strokes. If this occurs, it shall not be considered as adhesion failure of the test paint. In the same fashion, this topcoat shall be tested over the manufacturer’s primer coating complying with SSPC-Paint 23.

5.9 PACKAGE STABILITY: Perform the following tests in accordance with ASTM D 1849. When stored for one month at 123 to 127°F (51 to 53°C), the maximum allowable increase or decrease in viscosity shall not exceed 10 Kreb units. After brush­ing, the film shall be free from grains, lumps, or streaks.
5.10 FILM IRREGULARITY: Apply one coat of the latex paint by the drawdown method to a 4 x 8 inch (10 cm x 20 cm) cold-rolled steel panel to produce a dry film thickness of 4.0 ± 0.5 mils (102 ± 13 micrometers). Allow to dry at 74 to 80°F (23 to 27°C) and 50% ± 5% relative humidity for 48 hours. Examine the film for mud-cracking, alligatoring, or other film irregularity; there shall be none.
5.11 SALT SPRAY AND BLISTER RESISTANCE: Prepare quadruplicate 4 x 8 inch (10 x 20 cm) by 24 gage panels according to ASTM D 609, Type 2 steel. Spray-apply one coat of primer SSPC-Paint 23 to a dry film thickness of 2 to 3 mils (51 to 76 micrometers) and allow to dry for 48 hours at 74 to 80°F (23 to 27°C) at 50% ± 5% relative humidity. Then spray apply one coat of this paint to a dry film thickness of 2 to 3 mils (51 to 76 micrometers). Allow the two-coat system to dry at 74 to 80°F (23 to 27°C) and at 50% ± 5% relative humidity for 14 days. Coat and seal all edges and the backside of each panel with a suitable protective coating.

Scribe a 3 inch (8 cm) “X” through the middle portion of the painted panels so as to expose the underlying metal before testing. The conditions of making the scratch shall be as described in ASTM D 1654.

Expose duplicate panels in the salt fog cabinet at an angle of 15 degrees from the vertical for 300 hours according to ASTM B 117. Examine the panels at 72-hour intervals for rusting and blistering. At the end of 300 hours, immediately examine for rusting and blistering. The rusting shall not exceed “8” according to SSPC-VIS 2 or ASTM D 610, and the blistering shall not exceed “8” according to ASTM D 714. After examining the panels for blistering, immediately remove the paint film with a suitable organic solvent. If scraping of the paint film is necessary to remove it, do not use a metal spatula or razor blade. Use a piece of soft wood. Examine the steel substrate. The rusting shall not exceed “9” as judged by SSPC-VIS 2 or ASTM D 610. The rust creep, as judged by the bare panel, shall not exceed 1/8 inch (3 mm) from the center of the scribe.

Expose the other pair of duplicate panels in a Cleveland Condensing Cabinet according to ASTM D 2247 for 300 hours at 100°F (38°C). Examine the panels at 72-hour intervals for rusting and blistering. At the end of 300 hours, immediately examine for rusting and blistering. The rusting shall not exceed “8” according to SSPC-VIS 2 or ASTM D 610, and the blistering shall not exceed “8F” according to ASTM D 714. After examining the panels for blistering, immediately remove the paint film with a suitable organic solvent. If scraping of the paint film is necessary to remove it, do not use a metal spatula or razor blade. Use a piece of soft wood. Examine the steel substrate. The rusting shall not exceed “9” as judged by SSPC-VIS 2 or ASTM D 610. The rust creep, as judged by the bare panel, shall not exceed 1/8 inch (3 mm) from the center of the scribe.

5.12 WET ABRASION RESISTANCE: Test the paint as described in ASTM D 2486. Air dry the panel for seven days in an open room kept at 74 to 80°F (23 to 27°C) and 50% ± 5% relative humidity before testing. A minimum of 800 strokes or 400 oscillations shall be required to fully remove the paint film on one continuous line across the width of the 1/2 inch (13 mm) shim.
5.13 FLEXIBILITY: Flexibility shall be determined in ac­cordance with ASTM D 1737 using a 1/4 inch (6 mm) mandrel and an unscribed panel as described below. Apply a 2 inch (5 cm) wide film of the paint with a film applicator that will give a dry film thickness of 0.9 to 1.1 mils (23 to 28 micrometers) on a smooth finish steel panel, prepared in accordance with ASTM D 609, paragraph 5.3 Method C, using the aliphatic naphtha-ethylene glycolmonoethyl ether mixture. The panel shall be new, cold-rolled, rust-free carbon steel No. 20 gage 0.0375 ± 0.0125 inch (0.95 ± 0.31 mm) thickness with a Rock-well 15T maximum hardness of 82 and finished with a surface roughness of 8 to 12 microinches. The coated panel shall air dry for 24 hours at a temperature of 74 to 80°F (23 to 27°C) and then put in an oven at 98 to 102°F (37 to 39°C) for four days. Condition the panel at 74 to 80°F (23 to 27°C) for two hours. Bend panel over a 1/4 inch (6 mm) mandrel. Examine the bend for paint cracking in a strong light at a seven diameter magnification. There shall be no visible cracking.
5.14 MILDEW RESISTANCE: When tested as specified in ASTM D 3273, the paint shall show no more mildew than disfigurement “8” when compared with the photographic stan­dards of ASTM D 3274.
5.15 GLOSS AFTER EXPOSURE: Coat duplicate suitable size anodized aluminum panels with two coats of this latex topcoat. Apply each coat at a dry film thickness of 2.0 ± 0.3 mils (51 ± 7 micrometers). Allow first coat to dry 24 hours at 74 to 80°F (23 to 27°C). Then apply the second coat to give a total dry film thickness of 4.0 ± 0.5 mils (102 ± 13 micrometers). Allow the two coats to dry 7 days at 74 to 80°F (23 to 27°C). Measure the 60 degree specular gloss according to ASTM D 523. Then subject the panels to light and water exposure for 400 hours according to ASTM G 23 or ASTM G 26. After exposure rinse the panels with clean water, allow to dry at room temperature for one hour, and again measure the 60 degree specular gloss. The gloss shall be no less than 80% of the original value.
5.16 HIDING POWER (CONTRAST RATIO): Determine the contrast ratio in accordance with ASTM D 2805. Use a film applicator that will deposit a 3 inch (8 cm) wide fi lm with a dry film thickness of 1 mil (25 micrometers). Air dry for 48 hours at 74 to 80°F (23 to 27°C). Determine the 45 degree, 0 degree directional reflectance according to ASTM E 97. Verify the thickness in the area in which the refl ectance was measured. Calculate the contrast ratio and check for compliance.

The minimum contrast ratio shall be 0.95 for paints that have a reflectance of 75% or more. For paints that have a directional reflectance of less than 75%, use the values in Table 3 for minimum contrast ratios. For the reflectance of chromatic specimens see ASTM D 2244.

5.17 DIRECTIONAL REFLECTANCE: Determine the 45 degree, 0 degree directional reflectance according to ASTM E 97. For white paints it shall not be less than 75%.

6. Labeling
6.1 Labeling shall conform to ANSI Z129.1.
6.2 Technical data shall be provided for at least all data elements categorized as “essential” in SSPC-Guide 13.
6.3 MARKING OF CONTAINERS: Each container shall be legibly marked with the following information:
Name: Latex, Semigloss Exterior Topcoat
Specification: SSPC-Paint 24
Color:
Lot Number:
Stock Number:
Date of Manufacture:
Quantity of Paint in Container:
Information and Warnings as may be required by
Federal and State Laws:
Manufacturer’s Name and Address:

6.3 DIRECTIONS FOR USE: The following directions for use shall be supplied with each container of paint:

Directions for Use of Latex, Semigloss Exterior Topcoat

This paint is intended for use as a topcoat over properly primed steel in atmospheric exposure. It is intended for use as a topcoat of a water-borne coating system consisting of two coats of primer (SSPC-Paint 23) and one or two coats of this water-borne topcoat (SSPC-Paint 24).

Mix paint thoroughly before use. If the pigment has settled, pour off most of the liquid. Thoroughly mix the pigment with the remaining liquid, taking care to scrape all the pigment off the bottom of the can. Gradually add the poured-off liquid and mix thoroughly. Mixing may be made easier by transfer­ring contents to a larger container or by pouring the paint to and from another container. Examine bottom of container for unmixed pigment. Screen paint before applying.

Thin paint only if necessary, using only deionized or po­table water. For brush application under normal conditions, no thinning should be necessary. For spray applications add up to one half pint of thinner per gallon (60 ml/L) of paint when necessary.

This paint may be applied by spray or brush. Cross brushing or cross spraying application is highly desirable. Application by spray tends to provide the best leveling. Apply to the specified film thickness or, if none is specified, to at least 2.0 mils (51 micrometers) dry or approximately 7 mils (178 micrometers) wet.

The atmospheric conditions at the time this coating is applied are extremely important. This paint shall not be applied at a temperature below 50°F (10°C) or above 120°F (49°C).

The best conditions for storage of this coating are at temperatures between 40°F (4°C) and 80°F (27°C). This coating shall never be allowed to attain temperatures over 120°F (49°C), or subjected to repeated freezing and thaw­ing.

Allow paint at least 24 hours drying time in good weather before recoating.

7. Inspection
7.1 All materials (coatings) supplied under this specification are subject to timely inspection by the purchaser or his autho­rized representative. The purchaser shall have the right to reject any materials supplied which are found to be defective under this specification (see Note 9.1). In case of dispute, unless otherwise specified, the arbitration or settlement procedure established in the procurement documents shall be followed. If no arbitration or settlement procedure is established, then a procedure mutually agreeable to the purchaser and material supplier shall be used.
7.2 Samples of paints may be requested by the purchaser and shall be supplied upon request along with the manufac­turer’s name and identification for the materials. Samples may be requested at the time the purchase order is placed or may be taken from unopened containers at the job site.
7.3 Unless otherwise specified, the sampling shall be in accordance with ASTM D 3925.

8. Disclaimer
8.1 While every precaution is taken to ensure that all information furnished in SSPC standards and specifications is as accurate, complete, and useful as possible, SSPC cannot assume responsibility nor incur any obligation resulting from the use of any materials, coatings, or methods specified herein, or of the specification or standard itself.
8.2 This specification does not attempt to address problems concerning safety associated with its use. The user of this specification, as well as the user of all products or practices described herein, is responsible for instituting appropriate health and safety practices and for ensuring compliance with all governmental regulations.

9. Notes
Notes are not requirements of this specification.
9.1 The procurement documents should establish the responsibility for samples, testing, and any required affidavit certifying full compliance with the specification.
9.2 ASTM and Federal Standard Test Methods listed as “canceled” or “withdrawn” are no longer maintained, but are still available as historical documents.

PAINT SPECIFICATION NO. 24 – Latex Semigloss Exterior Topcoat