1、SSPC-PS 28.02June 1, 20101SSPC: The Society for Protective CoatingsCOATing SySTem STAndArd PS 28.02Three-Coat moisture-Cured Polyurethane Coating System, Performance-Based 1. ScopeThis standard contains performance requirements for a coating system for steel substrates comprised of (1) a zinc-rich m
2、oisture-cured polyurethane primer (complying with SSPC-Paint 40), (2) a moisture-cured polyurethane intermediate coat (complying with SSPC-Paint 41), and (3) a single-component moisture-cured aliphatic polyurethane topcoat (complying with SSPC-Paint 38). The coating system is generally suitable for
3、exposures in SSPC Environmental Zones 1A (interior, normally dry), 1B (exterior, normally dry), 2A (frequently wet by fresh water, excluding immersion), 2B (frequently wet by salt water, excluding immersion),and 3B (chemical exposure, neutral). The primer/intermediate coat/topcoat system shall meet
4、the performance requirements of Sections 7 and 8 described in this standard. 2. description2.1 This coating system consists of three moisture-cured polyurethane coatings that are each supplied as single-package products. note: The zinc-rich primer may be supplied as either a single or two-component
5、product in accordance with SSPC-Paint 40, Section 2.1.2.2 The three coatings described herein are character-ized by the presence of free polyisocyanate groups capable of reacting with atmospheric moisture in order to form a solid film. Individual products meeting minimum performance require-ments of
6、 this standard may vary in formulation, raw materials, and application characteristics.2.3 The primer, intermediate coat and topcoat are intended for spray application with allowance for small area touch-up by brush (see Note 11.1). The topcoat is tolerant of larger-scale application by brush or rol
7、ler. All applications shall be in accordance with manufacturers instructions. 3. referenced Standards3.1 The latest issue, revision, or amendment of the referenced standards in effect on the date of publication of the project specification shall govern, unless otherwise specified. A standard marked
8、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 standard shall prevail.3.3 SSPC STAndArdS And JOi
9、nT STAndArdS: guide 13 Guide for the Identification and Use of Industrial Coating Materials in Computerized Product Databases PA 2 Measurement of Dry Coating Thick-ness with Magnetic GagesPaint 38 Single-Component Moisture-Cure Weatherable Aliphatic Polyurethane Topcoat, Performance-BasedPaint 40 Zi
10、nc-Rich Moisture Cured Polyure-thane Primer, Performance BasedPaint 41 Moisture-Cured Polyurethane Primer or Intermediate Coat, Micaceous Iron Oxide Reinforced, Performance-BasedSP 1 Solvent CleaningSP 5/nACe no. 1 White Metal Blast CleaningViS 2/ASTm d 610 Standard Method of Evaluating Degree of Ru
11、sting on Painted Steel Surfaces3.4 ASTm inTernATiOnAL STAndArdS:1A 572 Standard Specification for High-Strength Low-Alloy Columbium-Vanadium Structural Steel* d 512 Standard Test Methods for Chloride Ion in Water* d 520 Standard Specification for Zinc Dust Pigmentd 523 Standard Test Method for Specu
12、lar Gloss* d 562 Standard Test Method for Consistency of Paints Measuring Krebs Unit (KU) Viscosity Using a Stormer-Type Viscometerd 714 Standard Test Method for Evaluating Degree of Blistering of Paints d 1014 Standard Practice for Conducting Exterior Exposure Tests of Paints and Coatings on Metal
13、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 Organic Coatings at Room Temperatured 1654 Standard Test Method for Evaluation of Painted or Coated Specimens Subjected to Corrosive
14、 Environments 1ASTM International, 100 Barr Harbor Drive, West Conshohock-en, PA 19428-2959. Standards available online from http:/www.astm.org.SSPC-PS 28.02June 1, 20102d 2244 Standard Test Method for Calculation of Color Tolerances and Color Differences from Instrumentally Measured Color Coordinat
15、es* 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 for Infrared Identification of Vehicle Solids from Solvent-Reducible Paintsd 2794 Standard Test Method for Resistance of Organic
16、 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 for Pull-Off Strength of Coatings Using Portable Adhesion Testers* d 4940 Standard Test Method for Conductimetric Analysis of
17、Water Soluble Ionic Contamination of Blasting Abrasivesd 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 Resistance of Low-Alloy Steels3.
18、5 AmeriCAn nATiOnAL STAndArdS inSTiTUTe (AnSi) STAndArdS:2AnSi Z129.1 Hazardous Industrial ChemicalsPrecautionary LabelingAnSi B94.50 Basic Nomenclature and Definitions for Single-Point Cutting Tools4. Composition requirements4.1 reSinS And PigmenTS4.1.1 Primer: The resin used in the primer is chara
19、cter-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 11.2, 11.3, 11.4, and 11.5).4.1.2 intermediate Coa
20、t: The resin used in the interme-diate coat is characterized by the presence of free polyisocya-nate groups capable of reacting with atmospheric moisture in order to form a film. Other resin composition requirements are described in SSPC-Paint 41; as per SSPC-Paint 41, micaceous iron oxide is a requ
21、ired pigment component in this coating. 4.1.3 Topcoat: The resin used in the topcoat is character-ized by the presence of free polyisocyanate groups capable of reacting with atmospheric moisture in order to form a film in accordance with compositional requirements of SSPC-Paint 38, Section 4.1.2Amer
22、ican National Standards Institute, 1819 L Street, NW, Suite 600, Washington, DC 20036. Standards available online from www.ansi.org.5. Standard Testing Conditions5.1 TeST PAneLS: Triplicate panels shall be used for each test. Unless otherwise specified, the hot rolled steel test panels shall conform
23、 to ASTM A 572 (see Appendix A). Panel size shall be 100 mm x 150 mm x 6 mm (4 inch x 6 inch x inch). Test panels shall 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 blast profile shall be 44 to 57 mi
24、crometers (1.75 to 2.25 mils) as measured in accordance with ASTM D 4417, Method C.5.2 APPLiCATiOn: The primer, intermediate coat and topcoat shall be applied in accordance with the manufacturers recommendations, observing the defined recoat windows. The coatings shall show no streaking, running, sa
25、gging or other defects during application or while drying. 5.3 dry FiLm THiCKneSS: The dry film thickness (DFT) for each coat of the system (primer, intermediate coat and topcoat) on the test panels shall meet the manufacturers written recommended range (see Note 11.6). The DFT shall be measured in
26、accordance with SSPC-PA 2, Appendix 5.5.4. CUre: The primer, intermediate coat and the topcoat shall be dried and cured in accordance with manufacturers written recommendations unless otherwise specified (for example, for preparing panels for testing according to AASHTO R-31).3After application of t
27、he three coats in accordance with product data sheets, the coating system shall be aged for a minimum of 14 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. 5.5 SCriBing: Two vertical parallel l
28、ines shall be scribed on the face of the coated panels 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 scribe
29、s shall run parallel to the long axis of the panel so that they are positioned vertically when subjected to the specified exposure. Scribes shall be made using a straight-shank tungsten carbide tip lathe cutting tool (ANSI B94.50, Style E) following the procedure in Section 4.1 of ASTM D 1654.5.6 BA
30、CKS And edgeS: The edges and the back of each panel shall be sealed with coating or tape.6. requirements of Liquid CoatingsThe liquid primer shall meet the requirements of Paint 40; the liquid intermediate coat shall meet the requirements of Paint 41, and the liquid topcoat shall meet the requiremen
31、ts of Paint 38 (see Note 11.7).7. Laboratory Physical Tests of Applied Films7.1 Primer AdHeSiOn TO SUBSTrATe: Primer shall be applied to three panels in accordance with Sections 5.1 3AASHTO R-31, “Evaluation of Protective Coatings for Structural Steel”, American Association of State Highway and Tran
32、sporta-tion Officials (AASHTO), 444 North Capital Street, N.W., Suite 249, Washington DC 20001.SSPC-PS 28.02June 1, 20103through 5.4. Adhesion shall be tested according to ASTM D 4541, using an adhesion tester with a self-aligning pulling mechanism as described in ASTM D 4541. The type of adhe-sion
33、tester and adhesive employed shall be reported. Three pulls shall be performed on each of the three replicate panels.Results shall be reported in accordance with ASTM D 4541. The minimum adhesion value of the primer to the substrate for each pull shall be 4.1 MPa (600 psi).The instrument used to ver
34、ify compliance to this standard shall be of the same type used to perform the initial testing.7.2 inTermediATe And TOPCOAT AdHeSiOn TO Primer: Three panels shall be prepared according to Sections 5.1 through 5.4. The intermediate and topcoat shall be applied to the pre-primed steel panels in accorda
35、nce with manufac-turers instructions. Adhesion of the applied intermediate and topcoat to the primed steel panels shall be tested according to ASTM D 4541, using an adhesion tester with a self-aligning pulling mechanism as described in ASTM D 4541. The type of adhesion tester and adhesive employed s
36、hall be reported. Three pulls shall be performed on each of the three replicate panels. Results shall be reported in accordance with ASTM D 4541. 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 pane
37、l may be as low as 3.4 MPA (500 psi).The instrument used to verify compliance to this standard shall be of the same type used to perform the initial testing.7.2.1 recoat Window: In order to obtain optimum adhe-sion, the coating manufacturer shall provide an acceptable time frame between the applicat
38、ions 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 product data sheets shall be used for coating application pr
39、ocedures prior to adhesion testing.7.3 direCT imPACT reSiSTAnCe: The minimum impact resistance of the cured 3-coat system as applied to 3 test specimens shall be 0.69 kg-m (60 inch-lb) when measured in accordance with ASTM D 2794.7.3.1 Topcoat Testing: Other topcoat testing and perfor-mance requirem
40、ents, i.e., solvent, and chalking resistance, are described in SSPC-Paint 38, Table 4 with corresponding ASTM test methods.8. Weathering and Corrosion resistance requirements8.1 COLOr And gLOSS WeATHering reSiSTAnCe TeST PrOCedUreS8.1.1 Weathering: Test procedures with minimum color retention and ma
41、ximum gloss reduction values as specified in SSPC-Paint 38, Section 6 are the basis of performance accep-tance of the moisture-cured aliphatic polyurethane topcoat. 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. Th
42、ese test methods are specifically defined in SSPC-Paint 38, i.e., (1) three levels of accelerated testing and (2) three levels of natural exterior testing and are provided in Tables 1 and 2 with acceptance criteria shown in Table 3. 8.1.2 Outdoor Weathering: Triplicate test panels shall be prepared
43、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 be measured according to ASTM D 523 and tristimulus color measured according to ASTM D 2244 both initial
44、ly 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.8.2 Cyclic Salt Spray/UV/Condensation Cabinet: This three-coat coating system shall be applied to triplicate panels prepared in accordance with Section 5
45、 and shall be exposed in a cyclic test cabinet in accordance with ASTM D 5894 for 15 cycles (5040 hours). Performance acceptance criteria are 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
46、 SSPC-VIS 2/ASTM D 610). Moderate rusting in the scribe mark is permissible and resulting staining shall be ignored. Strips 6 mm (1/4 inch) wide 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 porti
47、on (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 Sections 5.1 through 5.5. After the specified exposure time, 12 maximum creepage measurements,one from each side of each scribe, shall be taken. The average value
48、 and the standard deviation shall be calculated. The maximum potential undercutting shall be calculated by determining the sum of the average and two standard deviations. The maximum creepage shall be 4 mm (3/16 inch) with an average creepage of 2 mm (3/32 inch) when evaluated in accordance with AST
49、M D 1654. Slight rusting in the scribe mark is permissible and resulting staining shall be ignored. 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
