Latex Primer for Steel Surfaces

Applying Latex Primer for Steel

PAINT SPECIFICATION NO. 23 – Latex Primer for Steel Surfaces

1. Scope
1.1 This specification covers an air drying, ready-mixed, water-borne primer for blast cleaned steel. It is intended for use as a primer coat of a water-borne coating system consisting of two coats of this primer and one or two coats of a water-borne topcoat.

1.2 This primer 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 steel surfaces prepared in accordance with SSPC-SP 6, “Commercial Blast Cleaning.” It is suitable as a shop primer, field primer, maintenance primer, or intermediate coat 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 primer 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 primer contains approximately 36% 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 290 square feet/U.S. gallon (7.1 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 AND JOINT STANDARDS:

3.4 ASTM INTERNATIONAL STANDARDS:
B 117 Method of Salt Spray (Fog) Testing
D 522 Test Methods for Mandrel Bend Test of Attached Organic Coatings
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 (Canceled) Elongation of Attached Organic Coatings with Cylindrical Mandrel Apparatus (Replaced with ASTM D522)
D 1849 Test Method for Package Stability of Paint
D 2243 Test Method for Freeze-Thaw Resistance of Water-Borne Coatings
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 (See ASTM D 4400.)
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

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 primer 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, antifoamer, preservatives, and “antifreeze” in order to produce a primer 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 4 mils (102 micrometers) wet film thickness on 400 square feet/gallon (9.8 square meters/liter) by brush, spray, or roller. Drying shall be done in a well-ventilated room or chamber free from drafts and dust 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, pinholing, eyeing, or cratering. 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 primer 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 primer 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″(15 cm x 43 cm 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 TT-E-506 by drawndown with a suitable applicator to obtain a dry film thickness of 3.0 ± 0.3 mils (76 ± 8 micrometers) and a width of 5-1/2″ (14 cm). Allow the alkyd enamel to dry in a horizontal position for three days at 74-80°F (23-27°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 74-80°F (23-27°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 underwater with the brush described in ASTM D 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 the alkyd undercoat after 1,500 strokes. The paint may wear through to the alkyd enamel in less than 1,500 strokes. If this occurs, it shall not be considered as adhesion failure of the test paint.

5.9 PACKAGE STABILITY: Perform the following tests in accordance with ASTM D 1849. When stored for one month at 123 to127°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 MECHANICAL STABILITY: Fill a one quart (one liter) friction top can three-quarters full with the primer and close the can tightly. Rotate on a jar roller for 168 hours at 120 to 170 rpm. At the end of 168 hours, there shall be no indication of separation, coagulation, excessive thickening or loss in mechanical stability. The maximum allowable increase or decrease in viscosity shall not exceed 10 Krebs units.
5.11 COALESCENCE TEST: Apply the primer to two 4″ x 8″ (10 cm x 20 cm) cold-rolled steel panels to produce a dry film thickness of 2.0 ± 0.5 mils (50 ± 13 micrometers).
(a.) Allow one panel to dry for four hours at 50% ± 5% relative humidity and at 47 to 53°F (8 to 12°C).
(b.) Allow the other panel to dry four hours at the same relative humidity as the first and at 74 to 80°F (23 to 27°C).

At the end of the four-hour drying period, allow both panels to remain at condition (b) above for 24 hours. At the end of 24 hours, brush one coat of alkyd enamel conforming to Federal Specification TT-E-506 to one-half of each panel. The enamel shall be tinted with lampblack to 45% to 55% apparent daylight
SSPC-Paint 23 November 1, 1982 Editorial Revisions November 1, 2004 reflectance. At the end of 24 hours, examine the enameled portion of the two panels for a difference in gloss. Differences in enamel hold-out will indicate unsatisfactory coalescence.

5.12 FILM IRREGULARITY: Apply one coat of the latex primer by the drawdown method to a 4 x 8 inch (10 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 24 hours. Examine the film for mud-cracking, alligatoring, or other film irregularity; there shall be none.
5.13 SALT SPRAYAND BLISTER RESISTANCE: Prepare quadruplicate 4 x 8 inch (10 x 20 cm) by 24 gauge panels according to ASTM D 609, Type 2 steel. Spray-apply two coats (allow 48 hours drying time between coats) to produce a total dry film thickness of 4.0 to 4.5 mils (102 to 114 micrometers). Allow 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 box 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 “8A” 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.

Expose the other pair of duplicate panels on 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 no 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.
5.14 FLASH RUST RESISTANCE TEST: Apply one coat of the primer at 1.5 mils (38 micrometers) dry film thickness to a panel prepared according to ASTM D 609, Type 2 steel.
Allow the panel to dry in a horizontal position for 48 hours at 74 to 80°F (23 to 27°C) and 50% ± 5% relative humidity. At the end of the drying period, examine for flash rusting or rust bleeding. The primer shall show no rust bleed and the steel shall not show any corrosion when the latex film is removed.
5.15 WET ABRASION RESISTANCE: Test the primer 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.
5.16 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 Rockwell 15T maximum hardness of 82 and finished with a surface rough­ness of 8 to 12 microinches (0.2 to 0.3 micrometers). The coated panel shall air dry for 24 hours at a temperature of 74 to 80°F (23 to 27°C) and then is 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.
5.17 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.

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 Primer for Steel Surfaces
Specification: SSPC-Paint 23
Color:
Lot Number:
Stock Number:
Date of Manufacture:
Quantity of Paint in Container:
Information and Warning as may be required by Federal and State Laws: Manufacturer’s Name and Address:
6.4 DIRECTIONS FOR USE: The following directions for use shall be supplied with each container of paint:

Directions for Use of Latex Primer for Steel Surfaces

This paint is intended for use as a primer over blast cleaned steel in atmospheric exposure. It is intended for use as a primer coat of a water-borne coating system consisting of two coats of this primer and one or two coats of a water-borne topcoat (SSPC-Paint 24). It may also be used over previously coated surfaces, galvanized steel, and aluminum surfaces.

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. Since one-coat systems have very limited protective properties, multiple coat systems shall always be applied. Apply to the specified film thickness or, if none is specified, to at least 2.0 mils (51 micrometers) dry or approximately 6 mils (152 micrometers) wet.

The atmospheric conditions at the time this coating is applied are extremely important. This primer 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 should 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 re-coating.

7. Inspection
7.1 All materials (coatings, primer) 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 standard itself.
8.2 This specification does not attempt to address prob­lems concerning safety associated with its use. The user of this primer 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. 23 – Latex Primer for Steel Surfaces