Detailed Performance
Standard
MPI # 20
Primer, Zinc Rich, Epoxy
Date of Issue: May 21, 2015
Supersedes: September 01, 2002
DETAILED PERFORMANCE STANDARD
MPI #20
Primer, Zinc Rich, Epoxy
1 SCOPE
1.1 This standard is for a 2 or 3 component, solvent-based epoxy zinc-rich primer intended for use on properly
prepared ferrous metal surfaces. This primer is also suitable for direct application to properly prepared
galvanized metal surfaces. In certain applications, this material may be exposed without a topcoat, or it
may be subsequently top coated with 2 component epoxy or polyurethane coatings.
1.2 For recommended substrates see Paragraph 6.
1.3 The tests specified in this standard may involve the use of materials or equipment that in their storage,
handling, use, or disposal may pose a danger to the environment and/or testing personnel. Conformance
to the pertinent national and regional safety and environmental requirements is the responsibility of the
user of this document.
2 TOXIC ELEMENTS
2.1 This paint will be manufactured and labeled to conform to the current Federal, State/Provincial and
Municipal safety and environmental regulations in regards to toxic elements.
3 REFERENCES
3.1 American Society for Testing Materials (ASTM) Volumes 6.01, 6.02, 6.03, 6.04
3.2 MPI Architectural Painting Specification Manual
3.3 MPI Maintenance Repainting Manual
4 REQUIREMENTS
4.1 The primer shall be suitable for application by airless or conventional spray; small areas may be applied by
brush. If thinning is required, the manufacturer will display information about the recommended thinner and
amounts in the directions for application. The material shall be capable of curing at temperatures between
o o o o
45 F (7 C) and 104 F (40 C) and a relative humidity range of 30 - 80%.
Test Name Min Max Test Method
ASTM
Dry time, Dry hard ---- 8 hrs D 1640
Full cure ---- 7 days ----
Zinc content - % of NV/Wt. 83% D 6580
Gloss 60 degrees ---- 35 Para. 7.7
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The Master Painters Institute Inc. MPI # 20 Supercedes: September 01, 2002
4.2 Corrosion Resistance
When applied and exposed for 1000 hours as specified in Paragraph 7.2, the primer shall comply with the
following requirements:
Scored Panels – shall show no more than 2mm under-creep when examined immediately after the exposure
period.
Un-scored Panels – shall show no rusting or evidence of blistering when examined immediately after the
exposure period.
4.3 Adhesion to Metal
When applied and tested according to the requirements of Paragraph 7.3, the material shall exhibit adhesion
of ASTM D 3359 4B. There shall be no separation of the paint film or delaminating of an entire square.
4.4 Topcoat Compatibility
There shall be no lifting, wrinkling, softening, blistering or other defects when a coat of MPI #108 is applied
over the primer following the procedure in Paragraph 7.4.
4.5 Cathodic Protection
When applied and tested according to the requirements of Paragraph 7.5, the coating shall prevent corrosion
in the 40 mm circular uncoated area.
4.6 Resistance to Mud Cracking
When applied and tested according to the procedure outlined in Paragraph 7.6, there shall be no mud
cracking.
4.7 Impact Resistance – Direct
When applied and tested according to the requirements of Paragraph 7.3, the film shall show no cracking,
flaking or chipping.
5 QUALITY ASSURANCE
5.1 Records
It will be the manufacturer’s responsibility to keep retained samples of each batch of qualified products for a
minimum of 2 years. Quality control records of qualified products must be maintained for a minimum of 3
years.
5.2 Formulation Changes
To maintain product listings in the MPI Architectural Painting Specification Manual and the MPI Maintenance
Repainting Manual, the manufacturer of a qualified product must notify, in writing, the MPI Testing Authority of:
a) Any changes to the paint formula in regard to types of materials, or ratios of materials, that may alter the
performance of the finished product or limit its use as specified in the MPI manuals. A testing report
confirming that the product continues to meet the requirements of the standard will be required for
evaluation. Evaluation of this report may result in a requirement for compliance testing to be performed by
MPI. All costs associated with any testing deemed to be required, shall be borne by the manufacturer.
b) Any changes to the code number, label or line name, so that the listing in the manuals can be up-dated.
Copyright © 2016 Page 3 Date of Issue: May 21, 2015
The Master Painters Institute Inc. MPI # 20 Supercedes: September 01, 2002
6 INTENDED USES
6.1 The primer complying with this specification is intended for application to properly prepared ferrous metal
surfaces. The primer is also suitable for direct application to properly prepared galvanized metal surfaces.
6.2 This primer may be exposed with or without a topcoat. Oil and alkyd topcoats are not suitable for direct
application over this material.
6.3 For details on specific uses, systems and surface preparation, refer to the MPI Architectural Painting
Specification Manual, or the MPI Maintenance Repainting Manual.
7 TESTING DETAILS
7.1 General
Sample preparations for the following tests shall be carried out in a well-ventilated room, free from dust, direct
drafts, combustive gasses and laboratory fumes. Maintain the temperature at
o
70 - 77F (21- 25 C) and the relative humidity at 50 ± 5% for the duration of the specified curing time. The
paint dry film thickness shall be 2.0 mils (50 microns) unless otherwise specified in the test method.
7.1.1 Agitation Procedure
The complete sample to be tested shall be shaken in a mechanical paint shaker for a minimum period of 2
minutes. The sample shall then be allowed to stand for 20 minutes at standard laboratory conditions (para. 7.1
General) prior to testing,
Testing must commence within 24 hours of shaking.
At the time of testing, the sample shall be manually stirred to determine if it completely homogenous (the ratio
of solute to solvent remains the same throughout the solution). If it is not, the sample shall be re-shaken using
the same method prior to proceeding with the panel preparation.
7.2 Salt Spray Resistance
Hot rolled steel test panels shall be approximately 4x6x1/8 inches (10x15x.3 cm). Panels shall be solvent
cleaned prior to use, following the procedure in ASTM D 609. After solvent cleaning, the panels shall be white
metal abrasive blast cleaned to SSPC-SP 5.
Apply the material under test to the freshly cleaned panels, to achieve a dry film thickness of 3 mils ± .25 mils
(76 ± 6 microns). Allow the coated panels to dry for 14 days under the conditions specified in Paragraph 7.1.
Prior to exposure, coat the backs and edges of the panels with the material under test or some other suitable
material. Scored panels shall be produced by drawing two score lines from corner to corner on the panel to
produce an X, the lines being produced with a sharp knife held at an angle of 30 degrees to the panel and the
plane of the blade perpendicular to the panel. The scoring must continuously expose the bright metal of the
panel.
Expose the panels for the specified period in a salt spray chamber conforming to the requirements of ASTM B
117. Support the panels at an angle of 15 degrees from vertical during the exposure period.
At the conclusion of the exposure period, remove the panels from the test chamber and rinse to wash away
any salt solution and soluble deposits. Examine the panels to determine compliance with the specified
requirements. If required, one half of the panel shall have the coating removed by use of a suitable “paint
stripper” to facilitate examination.
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The Master Painters Institute Inc. MPI # 20 Supercedes: September 01, 2002
7.3 Adhesion to Metal
Apply a coat of the material under test by spray to achieve a DFT of 3 mils ± .25 mils (76 ± 6 microns) on two
(2) hot rolled steel test panels approximately 4x6x1/8 inches (10x15x.3 cm). Panels shall be solvent cleaned
prior to use, following the procedure in ASTM D 609. After solvent cleaning, the panels shall be white metal
abrasive blast cleaned to SSPC-SP 5. Dry under the conditions described in Paragraph 7.1 for 7 days. At the
end of the drying period, perform an adhesion test following the procedures prescribed in ASTM D 3359
Method B and classify the results according to the visual standards contained in this method. Two (2)
determinations shall be performed on each panel.
7.4 Topcoat Compatibility
Apply a coat of the material under test by spray to achieve a DFT of 3 mils ± .25 mils (76 ± 6 microns) on hot
rolled steel test panels approximately 4x6x1/8 inches (10x15x.3 cm). Panels shall be solvent cleaned prior to
use, following the procedure in ASTM D 609. After solvent cleaning, the panels shall be white metal abrasive
blast cleaned to SSPC-SP 5. Dry under the conditions described in Paragraph 7.1 for 24 hours.
At the end of this period, apply a coat of MPI #108 to the primed area by spray to obtain a dry film thickness of
5 ± .25 mils (125 ± 6 microns). Allow the topcoat to dry for 24 hours under the conditions described in
Paragraph 7.1 and examine for film defects.
7.5 Cathodic Protection
Using panels as described in Paragraph 7.4, mask a 40mm diameter circle in the center of the panel face.
Apply a coat of the material under test to achieve a DFT of 3 mils ± .25 mils (76 ± 6 microns). Remove the
masking prior to allowing the coating to dry for 7 days under the conditions specified in Paragraph 7.1. At the
end of this drying period, immerse the panel in synthetic seawater (Note 1) contained in a borosilicate glass
beaker for 30 days. During the exposure period maintain the liquid level by the addition of distilled water. At
the conclusion of the exposure period, examine the bare area for corrosion.
7.6 Resistance to Mud Cracking
Using panels as described in Paragraph 7.4, apply the material under test to achieve a DFT of 5.5 mils ± .25
mils ( 125 ± 6 microns) After drying 18 hours, examine the film for evidence of mud cracking, by use of a 10X
magnifier.
7.7 Impact Resistance – Direct
Apply a film of the coating under test to a cleaned steel panel (Note 2). Prior to coating, the panels shall be
abrasive blasted in accordance with SSPC-SP 5. The coating shall be applied at a rate, which will provide a
dry film thickness of 3 mils ± .25 mils (76 ± 6 microns). Allow the coated panels to cure under the conditions
noted in Paragraph 7.1 for 7 days. At the conclusion of the curing period, perform the impact resistance test
following the procedure specified in ASTM D2794. The test should be performed as a direct impact in a
manner to produce an intrusion using an impact force of 40 kg/cm.
Note(s)
1 Synthetic sea Water shall consist of the following:
Magnesium chloride hexahydrate, MgCl2, 6H2O. …..11.0 g
Calcium chloride, anhydrous, CaCl2………………….. 1.2 g
Sodium Sulfate, anhydrous, Na2SO4………………… 4.0 g
Sodium Chloride, NaCl…………………………………25.0 g
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The Master Painters Institute Inc. MPI # 20 Supercedes: September 01, 2002
Dissolve above salts in sufficient distilled water to obtain I liter of solution. Adjust pH of solution to 8.0 –
8.2 by the addition of a 5% aqueous solution of sodium carbonate.
2 Steel panels shall be as supplied by “Q Panel” number R36 - Dull Matte Finish. Steel panels meeting this
requirement are available from Byk Gardner or Paul N. Gardner Co, Inc.
8 LABELING
8.1 Each container shall be labeled to show:
i) The name of the material
ii) The manufacturer’s address
iii) The manufacturer’s batch number and product code number
iv) The date of manufacture or packaging
v) The color number
vi) Application and thinning instructions
vii) Storage requirements
viii) MPI standard and code number for listing
ix) Any safety information required by Federal, State or Provincial safety authority
9 CALL-UP TESTING AND LISTING REQUIREMENTS
9.1 Before initial qualification and approval for listing, products shall be tested by MPI to assure compliance
with the specified requirements of the standard. After listing, continued compliance with the specified
requirements of the standard will be confirmed by periodic MPI confirmation testing. Both initial and
confirmation testing will be performed by MPI and the applicable costs billed to the manufacturer.
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The Master Painters Institute Inc. MPI # 20 Supercedes: September 01, 2002
