1、SSPC-PS 28.01April 1, 20091SSPC: The Society for Protective CoatingsCOATING SYSTEMSSPC-PS 28.01Two-Coat Zinc-Rich Polyurethane Primer/ Aliphatic Polyurea Topcoat System, Performance-Based1. ScopeThis specification contains performance requirements for a coating system for steel substrates that consi
2、sts of a zinc-rich moisture-cure polyurethane primer (complying with SSPC-Paint 40) and an aliphatic polyurea topcoat (complying with SSPC-Paint 39, Type 2) 1.1 The coating system is generally suitable for expo-sures in SSPC Environmental Zones 1A (interior, normally dry), 1B (exterior, normally dry
3、), 2A (frequently wet by fresh water, excluding immersion), 2B (frequently wet by salt water, excluding immersion), 3B (chemical exposure, neutral) and 3C (chemical exposure, alkaline). The primer/topcoat system shall meet the performance requirements of Sections 7 and 8 described in this standard.
4、2. Description2.1 This coating system consists of a polyurethane zinc-rich primer and a two-component aliphatic (moderate-dry) polyurea topcoat. The prerequisite requirements of the primer and topcoat shall be in accord with those stipulated in SSPC-Paint 40 (primer) and SSPC-Paint 39 (topcoat). Ind
5、ividual products meeting minimum performance requirements of this standard may vary in formulation, raw materials, and applica-tion characteristics.2.2 The primer is intended for spray application with allowance for small area touch-up by brush (see Notes 11.1 and 11.2). The polyurea topcoat is inte
6、nded for application by single-component airless spray, electrostatic spray, or plural-component equipment, depending upon its formulation.3. Referenced Standards3.1 The latest issue, revision, or amendment of the refer-enced standards in effect at the time of the bid solicitation shall govern, unle
7、ss otherwise specified. A standard marked with an asterisk (*) is referenced only in the Notes or the Appendix, which are not requirements of this standard.3.2 If there is a conflict between the requirements of any of the cited reference standards and this standard, the require-ments of this standar
8、d shall prevail.3.3 SSPC STANDARDS AND JOINT STANDARDS: Guide 13 Guide for the Identification and Use of Industrial Coating Materials in Computerized Product Data-bases PA 2 Measurement of Dry Coating Thick-ness with Magnetic GagesPaint 39 Two-Component Aliphatic Polyurea Topcoat, Performance-BasedP
9、aint 40 Zinc-Rich Moisture Cure Poly-urethane Primer, Performance BasedPS 12.00 Guide to Zinc-Rich CoatingsSP 1 Solvent CleaningSP 5/NACE No. 1 White Metal Blast Cleaning3.4 ASTM INTERNATIONAL STANDARDS:1A 572 Standard Specification for High-Strength Low-Alloy Columbium-Vanadium Structural Steel * D
10、 512 Standard Test Methods for Chloride Ion in Water* D 520 Standard Specification for Zinc Dust PigmentD 523 Standard Test Method for Specular Gloss* D 562 Standard Test Method for Consistency of Paints Measuring Krebs Unit (KU) Viscosity Using a Stormer-Type ViscometerD 714 Standard Test Method fo
11、r Evaluating Degree of Blistering of Paints D 1014 Standard Practice for Conducting Exterior Exposure Tests of Paints on Metal Substrates* D 1475 Standard Test Method for Density of Liquid Coatings, Inks, and Related ProductsD 1640 Standard Test Methods for Drying, Curing, or Film Formation of Organ
12、ic Coatings at Room TemperatureD 1654 Standard Test Method for Evaluation of Painted or Coated Specimens Subjected to Corrosive Environments 1ASTM International, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959. Standards available online from http:/www.astm.org.SSPC-PS 28.01April 1, 20092D 2
13、244 Standard Test Method for Calculation of Color Tolerances and Color Differences from Instrumentally Measured Color Coordinates* D 2369 Standard Test Method for Volatile Content of Coatings* D 2371 Standard Test Method for Pigment Content of Solvent-Reducible Paints * D 2621 Standard Test Method f
14、or Infrared Identification of Vehicle Solids from Solvent-Reducible PaintsD 2794 Standard Test Method for Resistance of Organic Coatings to the Effects of Rapid Deformation (Impact)D 4417 Standard Test Methods for Field Measurement of Surface Profile of Blast Cleaned SteelD 4541 Standard Test Method
15、 for Pull-Off Strength of Coatings Using Portable Adhesion TestersD 4587 Standard Practice for Fluorescent UV-Condensation Exposures of Paint and Related Coatings * D 4940 Standard Test Method for Conductimetric Analysis of Water Soluble Ionic Contamination of Blasting AbrasivesD 5402 Standard Pract
16、ice for Assessing the Solvent Resistance of Organic Coatings Using Solvent RubsD 5894 Standard Practice for Cyclic Salt Fog/UV Exposure of Painted Metal, (Alternating Exposures in a Fog/Dry Cabinet and a UV/Condensation Cabinet)* G 101 Standard Guide for Estimating the Atmospheric Corrosion Resistan
17、ce of Low-Alloy Steels3.5 AMERICAN NATIONAL STANDARDS INSTITUTE (ANSI) STANDARDS:2ANSI Z129.1 Hazardous Industrial Chemicals Precautionary LabelingANSI B94.50 Basic Nomenclature and Definitions for Single-Point Cutting Tools3.6 AMERICAN ASSOCIATION OF HIGHWAY AND TRANSPORTATION OFFICIALS (AASHTO) SP
18、ECIFICA-TION3* Standard Specifications for Highway Bridges, Division1, Section 10.32.3.2.3, Appendix A, Testing Method to Determine the Slip Coefficient for Coatings Used in Bolted Joints2American National Standards Institute, 1819 L Street, NW, Suite 600, Washington, DC 20036. Standards available o
19、nline at http:/www.ansi.org.3American Association of State Highway and Transportation Officials, 444 North Capitol Street, NW, Suite 249, Washington DC 20001. Standards are available online at https:/bookstore.transportation.org.4. Composition Requirements4.1 RESINS AND PIGMENTS4.1.1 Primer: The res
20、in used in the primer is character-ized by the presence of free polyisocyanate groups capable of reacting with atmospheric moisture in order to form a film. The major pigment component is zinc dust. Composition requirements of the primer are described in SSPC-Paint 40 (see Notes 11.3, 11.4, and 11.5
21、).4.1.2 Topcoat: The resins used in the topcoat are comprised of a hindered polyamine and a polyisocyanate that react to form an aliphatic polyurea with a moderate dry time (to handle) of thirty minutes to two hours (see Note 11.6). Composition requirements of the topcoat are described in SSPC-Paint
22、 39 (Type 2).5. Standard Testing Conditions5.1 TEST PANELS: Triplicate panels shall be used for each test. Unless otherwise specified (see Appendix A), the hot-rolled steel test panels shall conform to ASTM A 572. Panel size shall be 100 mm x 150 mm x 6 mm (4 inch x 6 inch x inch). Test panels shall
23、 be solvent cleaned in accordance with SSPC-SP 1 prior to blast cleaning. The test panels shall be blast cleaned in accordance with SSPC-SP 5. The average blast profile for each test panel shall be between 44 to 57 micrometers (1.75 to 2.25 mils) as measured in accordance with ASTM D 4417, Method B.
24、 The average profile for each test panel shall be computed from 20 measurements. 5.2 APPLICATION: The primer and topcoat shall be spray-applied in accordance with the manufacturers recommenda-tions. The coatings shall show no streaking, running, sagging or other defects during application or while d
25、rying. 5.3 DRY FILM THICKNESS: The dry film thickness (DFT) for the primer and topcoat on the test panels shall meet the manufacturers written recommended range (see Note 11.7). The DFT of the primer alone and of the primer plus the topcoat (i.e. the complete system) shall be measured and recorded.
26、The DFT shall be measured in accordance with SSPC-PA 2, Appendix 5.5.4. CURE: The primer and the topcoat shall be dried and cured in accordance with manufacturers written recom-mendations. Unless otherwise specified (for example, for preparing panels for testing according to AASHTO R-31) all coated
27、panels shall be aged for a minimum of 7 days in an environment with a minimum relative humidity of 50%, and at a temperature of 23 2 C (73.5 3.5 F), as described in paragraph 5.1 of ASTM D 1640.SSPC-PS 28.01April 1, 200935.5 SCRIBING: Scribe two parallel lines on the face of the coated panels so as
28、to expose the underlying metal before testing. The lines shall be at least 2.5 cm (1 inch) from the edge, the top, and the bottom of each panel and at least 5 cm (2 inches) from each other. Each scribe shall be 6 cm (2.4 inches) long. The scribes shall run vertically across the face of the panel. Fo
29、llow the scribe-making procedure described in ASTM D 1654 utilizing a straight-shank tungsten carbide tip, lathe-cutting tool (ANSI B94.50, Style E).5.6 BACKS AND EDGES: Coat and seal all edges and the back of each panel with a coating or tape that will provide the necessary protection to these surf
30、aces.6. Requirements of Liquid CoatingsThe liquid primer shall meet the requirements of Paint 41 and the liquid topcoat shall meet the requirements of Paint 39 (see Note 11.8).7. Laboratory Physical Tests of Applied Films7.1 PRIMER ADHESION TO SUBSTRATE: Apply the primer to three panels in accordanc
31、e with Sections 5.1 through 5.4. Test adhesion according to ASTM D 4541, using an adhesion tester with a self-aligning pulling mechanism as described in ASTM D 4541. Report the type of adhesive and the adhesion tester employed. Perform three pulls on each of the three replicate panels. The minimum a
32、dhesion value of the primer to the substrate for each pull shall be 4.1 MPa (600 psi). In the case of adhesive failure below 4.1 MPa (600 psi), the pull test shall be repeated. The instrument used to verify compliance to this standard shall be of the same type used to perform the initial testing.7.2
33、 TOPCOAT ADHESION TO PRIMER: Prepare three panels according to Sections 5.1 through 5.4. Test adhesion according to ASTM D 4541, using an adhesion tester with a self-aligning pulling mechanism as described in ASTM D 4541. Report the type of adhesion tester employed. Perform three pulls on each of th
34、e three replicate panels. At least two of the pulls on each panel as well as the average of the three pulls on each panel shall be at least 4.1 MPa (600 psi). One pull on each panel may be as low as 3.4 MPa (500 psi).7.2.1 Recoat Window: In order to obtain optimum adhe-sion, the coating manufacturer
35、 shall provide an acceptable time frame between the applications of coatings in a multi-coat system. Unless the purchaser specifically requests a variance, the maximum dry film thicknesses and minimum curing time (with reported conditions for temperature and humidity) as stated on the manufacturers
36、product data sheets shall be used for coating application procedures prior to adhesion testing.8. Weathering and Corrosion Resistance Requirements8.1 Color and Gloss Weathering Resistance Test Procedures8.1.1 Weathering: Test procedures with minimum color and gloss values as specified in SSPC-Paint
37、39, Section 8 are the basis of performance acceptance of the polyurea topcoat (see Note 11.9). It is left to the discretion of the specifier whether to accept outdoor data or to use UV-A data in lieu of outdoor weathering data. These test methods are specifically defined in SSPC-Paint 39, i.e., (1)
38、three levels of accelerated testing and (2) two levels of natural exterior testing are provided with acceptance criteria shown in Table 1.8.1.1.1 Level 1A: Products conforming to this performance level shall have a maximum gloss reduction of 20% and maximum color change of 2.0 E* after a 500 h expos
39、ure.8.1.1.2 Level 2A: Products conforming to this performance level shall have a maximum gloss reduction of 30% and maximum color change of 3.0 E* after a 1000 h exposure.8.1.1.3 Level 3A: Products conforming to this performance level shall have a maximum gloss change of 40% and a maximum color chan
40、ge of 3.0 E* after a 2000 h exposure.8.1.2 Outdoor Weathering: Triplicate test panels shall be prepared in accordance with Sections 5.1 through 5.4. Outdoor weathering shall be performed in accordance with ASTM D 1014 (45 degrees south exposure, washed with mild detergent). Sixty degree gloss shall
41、be measured according to ASTM D 523 and tristimulus color measured according to ASTM D 2244 both initially and at the end of each level period. The coating shall meet the weathering test requirements both initially and at the end of each level period.8.1.2.1 Level 1N: Products conforming to this per
42、formance level shall have a maximum gloss change 35% and a maximum color change of 2.0 E* after a 12-month exposure.8.1.2.2 Level 2N: Products conforming to this performance level shall have a maximum gloss change 50% and a maximum color change of 3.0 E* after a 24-month exposure.Note: Table 1 shows
43、 acceptable color retention values of the polyurea topcoat (per ASTM D 2244) that are in an approximate range of 2 to 3 E* depending upon the type of exposure test selected. Maximum gloss reductions from original readings range from 20% to 50% (per ASTM D 523) depending upon the selected test exposu
44、re.8.2 Cyclic Salt Spray/UV/Condensation Cabinet: The coating system shall be applied to triplicate panels prepared in accordance with Section 5 and shall be exposed in a cyclic test SSPC-PS 28.01April 1, 20094cabinet in accordance with ASTM D 5894 for 15 cycles (5040 hours). Performance acceptance
45、criteria is as follows:8.2.1 Rust Evaluation: After the specified exposure time, each replicate panel shall have no rusting of the coated portion (a rust rating of 10 per SSPC-VIS 2). Moderate rusting in the scribe mark is permissible and resulting staining shall be ignored. Strips 6 mm (1/4 inch) w
46、ide along the edges of the panel shall be ignored.8.2.2 Blister Evaluation: After the specified exposure time, there shall be no blistering of the coated portion (a rating of 10 per ASTM D 714).8.2.3 Scribe Evaluation: The coating shall be applied to triplicate panels prepared in accordance with Sec
47、tions 5.1 through 5.5. Undercutting shall be measured after removing the coating along the scribe by scraping with a suitable instrument. Visible areas of corrosion along the scribe are measured. Measure 12 maximum undercutting values, one from each side of each scribe. Calculate the average of the
48、12 maximum values and the standard deviation. Compute the scribe undercutting test parameter, U, as the average plus two standard deviations (U = x + 2s). Report the number of data points, average undercutting, standard deviation, and scribe undercutting test parameter. The maximum U shall be 4 mm.
49、The maximum x shall be 2 mm.9. Labeling 9.1 Labeling shall conform to ANSI Z129.1. 9.2 Technical data shall be provided for at least all data elements categorized as “essential” in SSPC-Guide 13.10. Disclaimer10.1 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.Exposure TestPerform
