Technical Data Sheet
Rinseable Primer RP-1
Low Viscosity Primer (High pH)
Introduction
Rinseable Primer RP-1 is a low viscosity sprayable liquid used to pretreat and clean roof membranes.
Use Rinseable Primer RP-1 to pretreat black EPDM rubber roof membrane prior to power washing
and application of elastomeric roof coatings. Its distinct chemistry is designed for use with elastomeric
roof coating formulations that feature RHOPLEX™ EC-1791, RHOPLEX™ EC-3000 and RHOPLEX™
EC-3100. It may also be used to clean TPO membrane prior to applying RHOPLEX™ EC-3100.
Pretreatment or cleaning with Rinseable Primer RP-1 significantly improves the adhesion of appropriate coatings to EPDM rubber and TPO membranes.
Typical Physical Properties
These properties are typical but should not be considered specifications.
Appearance
Clear liquid
Color
Pink
Odor Mild
pH
13.0-13.5
Specific gravity, g/cc
1.01
Density, wet, lbs/gal
8.46
Solubility in water
Completely soluble
Performance
Data
Roof Trial Exposures
Figure 1: RHOPLEX™ EC-1791 coating (20 mil dry thickness with
embedded scrim) on EPDM roof after six months of exposure; power
washed with water only – adhesive failure.
Figure 2: Rinseable Primer RP-1 treatment; power washed with water
(clean and rinse) – cohesive failure and fabric delamination
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Laboratory Data
Wet Adhesion Performance of RHOPLEX™ EC-1791 Roof Coating on Black EPDM Rubber(1)
Surface Treatment
Power Wash With Water
RP-1 Followed by Power Wash With Water
New EPDM(2), pli
0.4
1.3
Aged EPDM(3), pli
0.5
1.3
(1)
Test Method ASTM C794, two-coat application to achieve 18-20 dry mil film thickness (minimum).
(2)
Samples were conditioned for 14 days at 23°C and 50% RH, then soaked in tap water for seven days before testing (Test Method ASTM C794).
(3)
Measurements were taken after an accelerated dry time. Samples were conditioned for three days at 23°C and 50% RH, two days in a 50°C oven, two days
at 23°C and 50% RH, then soaked in tap water for seven days before testing.
Guidelines for
Laboratory
Evaluation of
Rinseable
Primer
Applications
1. Secure EPDM rubber membrane to a flat surface, such as plywood, with the side to be tested facing up. The membrane needs to be secure enough so that it will not flutter while undergoing
the power washing step.
2. Apply Rinseable Primer RP-1 to the EPDM at a spread rate of 500 sq ft/gal. This may be
accomplished with any convenient method, including the use of a spray bottle, or simply pouring
and spreading Rinseable Primer RP-1 with a brush. (Caution: Rinseable Primer RP-1 is a high
pH surface treatment. Please read the MSDS thoroughly before use of this product.)
3. Allow Rinseable Primer RP-1 to remain on surface for a minimum of 15 minutes. Rinseable
Primer RP-1 can remain on the surface for up to two hours.
4. Clean the EPDM rubber membrane with a commercial power washer (between 2,000-3,500
psi) and water. When cleaning the EPDM, it should be done slowly and close to the surface in
order to remove mica and inorganic release agents. Failure to use a power washer will result
in poor adhesion.
5. Rinse thoroughly with power washer. The rinse step may be done at a faster pace than the
cleaning step. The final rinse water should be clear with no soap bubbles present.
6. Allow the EPDM surface to dry before applying the coating. No visible dampness or wet spots should be evident.
7. The substrate is now ready for coating for peel adhesion and blister resistance testing.
180 Degree Peel Adhesion Test
8. Prepare two test samples with each cleaning treatment by bonding 3" x 6" pieces of Rinseable
Primer RP-1 treated EPDM as well as an untreated or water power washed EPDM membrane (used as a control) to rigid substrates such as plywood or aluminum sheet.
9. Apply the test coating in accordance with ASTM C794 to the treated and untreated EPDM
membranes. Use enough coating to achieve an 18-20 dry mil film thickness in one coating
application. Each test sample should have two 1" wide strips of embedded fabric in the coating
so that the test can be carried out in duplicate.
a. Apply approximately 25%-35% of the coating to the EPDM.
b. Smear approximately 6" of one piece of fabric with coating and force the coating through both sides of the fabric.
c. Lay the impregnated fabric over the coated EPDM and lightly brush the top of the fabric in order to push out trapped air bubbles.
d. Repeat steps b and c for second fabric strip.
e. After both fabric strips are embedded in the coated EPDM, apply remaining coating quantity to achieve an 18-20 dry mil film thickness.
10. Cure the adhesion samples for 14 days at 75°F and 50% relative humidity.
11. After 14 days, make four cuts with a sharp blade lengthwise along the edges of the fabric in
order to separate a 1" coating-covered fabric strip for testing. Cut completely through to the
substrate surface.
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12. Test dry adhesion using a tension-testing machine in accordance with ASTM C794 on one set
of the two adhesion samples. Place the adhesion sample in the testing machine and peel the
fabric back at a 180° angle at a separation rate of 2"/min.
13. Immediately after dry adhesion is tested, immerse the second set of adhesion samples in
water for seven days.
14. Test wet adhesion according ASTM C794.
15. Calculations are done in accordance with ASTM C794. Adhesion results are reported in
pounds per linear inch (pli) by averaging the two values. Record failure mode as adhesive or
cohesive and record any indication of cloth failure.
Blister Resistance Test (Ponding)
1. Pretreat EPDM rubber membrane as described under “Rinseable Primer Application.”
2. Cut a 9" square from the treated EPDM rubber membrane, then cut 3" diagonals at the four
corners.
3. Form the membrane into a bowl shape by overlapping the corners and place into a container
such as a plastic food container (about 5.5" x 5.5" x 2.5" height). Cut down further to fit into
the container if necessary. There should not be gaps where membrane overlaps. (Note: Any
size container can be used. This is a good size for a bench top test.)
4. Apply the test coating via brush in two coats with a minimum of four hours between each coat.
Use enough coating to achieve approximately 18-20 dry mil thickness.
5. Allow the coating to dry for 14 days at 75°F and 50% relative humidity.
6. Fill the containers approximately 2/3 full with tap water. Place container lid or aluminum foil
over top to prevent rapid evaporation.
7. Monitor coating over time for blisters or loss of adhesion.
Recommended Application Instructions on a Roof
1. Apply Rinseable Primer RP-1 via a sprayer (Hudson-type agricultural, conventional pressure
or airless) at an application rate of 500 sq ft/gal.
2. Use a 3'-4' arc pattern.
3. Allow Rinseable Primer RP-1 to stand for a minimum of 15 minutes.
4. Clean EPDM with a commercial power washer (between 2,000-3,500 psi). When cleaning the
EPDM, it should be done slowly and close to the surface in order to remove mica and
inorganic release agents.
5. Rinse thoroughly with power washer. The rinse step may be done at a faster pace than the
cleaning step. The final rinse water should be clear with no soap bubbles present.
6. The EPDM will range from muddy brown to black after washing with Rinseable Primer RP-1.
7. When the surface is dry, coating can begin.
Packaging
Rinseable Primer RP-1 can be supplied in 55-gallon drums.
Purchasing
Guidelines
Dow recommends the following guidelines for customers who wish to purchase Rinseable
Primer RP-1:
• Customer’s roof coating must be based on RHOPLEX™ EC-1791, EC-3000 or EC-3100
technology. The technology in Rinseable Primer RP-1 is a lock and key technology with the
chemistry of these products.
• The Elastomeric Roof Coatings Technical Service Team at Dow’s Spring House Laboratories
offers a free first time service of testing to help ensure the RP-1 treatment enhances the
performance of the customer’s coating.
• Customer must read the MSDS and be fully aware of the safety issues associated with the
use of Rinseable Primer RP-1.
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July 2010
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Stewardship
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environment in which we live. This concern is the basis for our product stewardship philosophy
by which we assess the safety, health and environmental information on our products and
then take appropriate steps to protect employee and public health and our environment. The
success of our product stewardship program rests with each and every individual involved with
Dow products – from the initial concept and research to manufacture, use, sale, disposal and
recycle of each product.
Customer Notice
Dow strongly encourages its customers to review both their manufacturing processes and
their applications of Dow products from the standpoint of human health and environmental
quality to ensure that Dow products are not used in ways for which they are not intended or
tested. Dow personnel are available to answer your questions and to provide reasonable
technical support. Dow product literature, including safety data sheets, should be consulted
prior to use of Dow products. Current safety data sheets are available from Dow.
Disclaimer
NOTICE: No freedom from infringement of any patent owned by Dow or others is to be
inferred. Because use conditions and applicable laws may differ from one location to another
and may change with time, the Customer is responsible for determining whether products and
the information in this document are appropriate for the Customer’s use and for ensuring that
the Customer’s workplace and disposal practices are in compliance with applicable laws and
other governmental enactments. The product shown in this literature may not be available for
sale and/or available in all geographies where Dow is represented. The claims made may not
have been approved for use in all countries. Dow assumes no obligation or liability for the
information in this document. References to “Dow” or the “Company” mean the Dow legal
entity selling the products to Customer unless otherwise expressly noted.
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OR FITNESS FOR A PARTICULAR PURPOSE ARE EXPRESSLY EXCLUDED.
The Dow Chemical Company
www.dowconstructionchemicals.com
215-592-3000
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July 2010