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PRIMER 302





Technical Data & Application Instructions

Corrosion Resistant Polyurethane Primer

PRODUCT DESCRIPTION
PRIMER 302 is a two component, high performance corrosion resistant primer. It combines corrosion inhibiting pigments with a cross-linking polymer resin to form a highly stable polymer-pigment matrix. PRIMER 302 creates a physical and chemical bond between the substrate and polyurethane elastomer's. This superior bond strength is achieved by chemically cross-linking the polymer in the primer to the polyurethane elastomer topcoat.

PRIMER 302 is manufactured in Light Gray color only.

BASIC USES
PRIMER 302 was specifically developed to provide maximum adhesion of Elastuff Polyurethane Coatings to steel, stainless steel and aluminum (mill finish).

PRIMER 302 can also be used beneath an approved topcoat under constant immersion conditions.

PHYSICAL PROPERTIES
1. Mixing Ratio: four parts A to one Part B by volume (4A:1B)

2. Mixed Usable Pot Life: 24 hours at 75°F (24°C), 50% R.H.

3. Solids by Weight (Mixed): 51% (+2) [ASTM D 2369]

4. Solids by Volume (Mixed): 34% ( + 2) [ASTM D 2697]

5. Flash Point:  Part A: 40°F (4°C)  Part B: 80°F (27°C)  [Seta-Flash closed cup]

6. Temperature Limits for Service Conditions: -70°F to 200°F (-56°C to 93°C)

7. Dry Time: 30 minutes at 75°F (24°C), 50% R.H.

PACKAGING & MIXING
PRIMER 302 is a two component material available in 1.25-gallon units (4.7 liters) which is 4 parts of Part A 1-gallon (3.8 liters) and 1 part of Part B 1-quart (0.95 liters) and 5-gallon units (19 liters) a 5-gallon pail containing 4 gallons (15.2 liters) of Part A and a 1-gallon can (3.8 liters) of Part B, to enable easier mixing with the Part B component in the same container. Special packaging is available.

Mix 4 VOLUMES OF PART A WITH 1 VOLUME OF PART B. THINNING OR REDUCING THE MIXTURE IS NOT NORMALLY RECOMMENDED. If thinning is desired, used Methyl Ethyl Ketone (MEK) only. Material shall be thoroughly mixed prior to application. Use an air-operated or other explosion-proof mixer, which has been grounded and bounded, with a blade capable of uniformly mixing entire container.

Allow mixture to set a minimum of twenty (20) minutes for sweat-in before using. Mixed usable pot life of the mixture is 24 hours at 75°F (24°C), 50% R.H. At higher temperatures, usable pot life is shortened.

Shelf life of Part A and Part B components in unopened containers is one (1) year. Store at temperatures between 50°F and 100°F (10°C and 38°C). Do not open containers until ready to use the material.




PERFORMANCE & ADVANTAGES

1. Resistance to Condensation*:
Test panels were placed in the QCT Condensation Cabinet and maintained at a temperature of 120°F (49°C) and 100% relative humidity. PRIMER 302 had no loss of adhesion, no blistering or softening, and no corrosion was observed beneath the film. Visual observations were made within 30 minutes after test panels were removed from the test chamber and again after 24 hours following the test. Tested in accordance with ASTM D 2247.

2. Adhesion*:
Test panels primed with PRIMER 302 were cross-cut, forming a grid area of 100 squares. Tape was then firmly placed across the center of the grid. After the tape was removed, the grid area was inspected for adhesion of the primer to the substrate under magnification. The results were 100% adhesion, meeting the requirements for a 5 B Classification as defined in the ASTM Standard. The edges of the cuts were completely smooth and none of the squares of the grid were detached. Tested in accordance with ASTM D 3359.

3. Resistance to Salt Spray*:
Test panels were placed in the Harshaw Salt Spray Cabinet and maintained at a temperature of 95°F (35°C), utilizing a sodium chloride fog, solution of not less than 5% by weight. Test panels were "X" scribed to initiate corrosion before being placed into the test chamber. After 500 hours of continuous testing, PRIMER 302 had no loss of adhesion, no blistering or softening, and no corrosion was observed beneath the film. Corrosion was observed on "X" cut. Visual observations were made immediately after test panels were removed from the test chamber. Tested in accordance with ASTM B 117.

4. Flexibility*:
PRIMER 302 retains its ability to withstand multiple 7/16" (1.11 cm) mandrel bends without cracking. Observations were made under 10 times magnification. Tested in accordance with Federal Test Method Standard No. 141a-6221.

5. Resistance to Impact**:
Gardner Impact Tester-PRIMER 302 did not shatter, crack or chip when struck by a direct impact of 60 inch pounds. Tested in accordance with Federal Test Method Standard No. 141a-6226.

6. Bond Strength:
PRIMER 302 was applied to steel test panels to a minimum thickness of 1.5 dry mils (38 dry microns). Steel panels were sandblasted to Near-White (SP10) prior to being primed. United's Elastuff 504 was then applied over the primed test panels to a minimum thickness of 38 dry mils (965 dry microns). After test panels were allowed to fully cure, the bond (peel) strength was tested using the Instron Universal Testing Instrument. Elastuff 504 reached its maximum elongation point and pulled parts of PRIMER 302 from the steel panels. The bond between the primer and the substrate proved to be outstanding. The peel strength of PRIMER 302 exceeded 75 lbs. per lineal inch [13.13 kN/m]. Tested in accordance with ASTM D 903.

7. Cathodic Disbondment:
Successful coatings for steel pipe subjected to negative voltage for corrosive resistance must pass rigid cathodic disbondment criteria as outlined in ASTM Standard G 8. It has been determined that a primer is an integral part of a coating system for successful cathodic protection. PRIMER 302 surpasses the most critical requirements and effectively bonds polyurethane elastomer's to steel pipe subjected to varying degrees of negative voltage.

8. Low & High Temperature Applications:
PRIMER 302 may be applied during temperatures down to 32°F [0°C] and when surface temperature does not exceed 150°F [66°C]. For applications below 32°F [0°C], consult Technical Service.

9. Fast Cure Time:
PRIMER 302 dries in 30 minutes at 75°F [24°C], 50% R.H. This allows topcoating on the same day thus maximizing work efficiency. Cure time can be adjusted for special requirements in relationship to time and temperature.

*Note: These tests were conducted using cold rolled steel panels Steel panels were sandblasted to Near-White (SP10) and then primed. PRIMER 302 was spray-applied in one coat to a minimum thickness of 1.5 dry mils [38 dry microns]. Test panels were than allowed to cure at 75°F [24°C], 5% R.H. for 6 days and then oven dried at 125°F [52°C] for 1 day before testing.

**Note: This test was conducted using stainless steel panels. Stainless steel was acid cleaned using 10% muriatic acid and then primed. PRIMER 302 was spray-applied and cured in the same manner as listed above.




PREPARATION OF STEEL SURFACES

Steel and fabrication defects, such as weld imperfections, delamination's, slivers, etc., should be corrected prior to starting abrasive blasting operations.

All previous paints or coatings on the substrate must be completely removed, including paints or coatings which are tightly adhered to the surface.

All burrs, jagged edges, undercuts, recesses, and surface defects shall be ground smooth. Porous welds shall be ground down to pinhole free metal.

Steel surfaces must be blast cleaned to either Near-White (SP10) or White Metal (SP5) depending upon the conditions under which the topcoat will be subjected to on a specific project. Wet or water vapor sandblasting is not recommended.

The following cleaning procedures are provided for guideline use only. Occasions will arise where the specified method of blast cleaning will not result in the achievement of the type of cleaning desired. It is suggested that Technical Service be contacted for recommendations on each specific application.

Cleaning procedures as specified herein shall be in strict conformance with the following applicable Steel Structures Painting Council (SSPC) Surface Preparation Specifications:

SSPC SPA Solvent Cleaning
SSPC SP5 White Metal Blast Cleaning
SSPC SP5 Near-White Blast Cleaning

All oil, grease, weld flux, and other surface contaminants shall be removed prior to blast cleaning by use of a solvent wash as defined in SSPC SP1 Solvent Cleanings

Excessive rust-scale shall be removed by mechanical means prior to blast cleaning.

Abrasive blast cleaning shall not be performed when surface temperature of the steel is LESS THAN 5°F (3°C) above the dew point of the ambient air when relative humidity exceeds 80% or when there is a possibility that the blasted surface will become wet before the primer can be applied.

The blast cleaned surface shall be primed by the end of the same work day, but in any event before any visible rusting occurs. If rusting occurs after blast cleanings the surface shall be reblasted before priming. If the steel surface is subjected to chemical contaminations priming of the blast cleaned surface must take place as soon as possible.

For inspection purposes the visual standards contained in the Pictorial Surface Preparation Standards For Painting Steel Surfaces, SSPCVIS 1-67T shall be used as a guide in determining the minimum degree of surface preparation.

Surface Preparation Specifications: NACE No. I (SSPC-SP5); NACE No. 2 (SSPC-SP10) and NACE Standard TM-01-70 (SSPC-VIS1-67T).



STEEL SUBJECT TO DRY ABRASION

1. Lightweight Abrasive Materials:
Blast Cleaning Surfaces shall be blast cleaned to a Near-White Blast Cleaned Surface Finish (SP10) with a minimum surface profile of 2 mils (50.8 microns).
Primer Surfaces shall be primed with PRIMER 302 to a minimum thickness of .80 and a maximum of 1.2 dry mils (20 to 30 dry microns).

2. Lightweight to Medium Abrasive Materials:
Blast Cleaning Surfaces shall be blast cleaned to a Near-White Blast Cleaned Surface Finish (SP10) with a minimum surface profile of 2+ mils (50.8+ microns).
Primer Surfaces shall be primed with PRIMER 302 to a minimum thickness of .80 and a maximum of 1.2 dry mils (20 to 30 dry microns).

3. Heavy Abrasive (Larger than 1"):
Blast Cleaning Surfaces shall be blast cleaned to a White Blast Cleaned Surface Finish (SP5) with a minimum surface profile of 3+ mils (76.2+ microns).
Primer Surfaces shall be primed with PRIMER 302 to a minimum thickness of 1.5 and a maximum of 2.0 dry mils (38 to 50 dry microns).



STEEL SUBJECT TO LIQUID SLURRY:

1. Plain Water and mineral Solids:
Blast Cleaning and Priming requirements as specified above for Lightweight Abrasive Materials.

2. Light Slurry with Lightweight to Medium Particles:
Blast Cleaning and Priming requirements as specified above for Lightweight to Medium Abrasive Materials.

3. Heavy Slurry:
Blast Cleaning and Priming requirements as specified above for Heavy Abrasive (Larger than 1").

Prior to the application of primer, all loose dust and blast particles shall be removed from the surface by use of a power vacuum. Dry air blow off and brush cleaning are not recommended.

Note: The above surface preparations as defined by the National Association of Corrosion Engineers are comparable to SSPC Surface Preparation Specifications: NACE No. 1 (SSPC-SP5); NACE No. 2 (SSPC-SP10) and NACE Standard TM-01-70 (SSPC-VIS1-67T).



APPLICATION
PRIMER 302 may be applied by conventional or airless spray. Airless spray is the preferred method. Any Airless spray equipment capable of 1,000 psi [6,890kPa] and 1/2 gallon per minute [1.9 1/minute] delivery can be used. A reversible self-cleaning spray tip with orifice size of .013" to .019" [.33 to .48 mm] and minimum 40 degree fan angle is recommended.

Coverage rate will depend upon the surface profile. For surfaces which have been sandblasted to a 2 mil profile. PRIMER 302 should be applied at a minimum rate of 1 gallon per 250 to 300 sq. ft. [6.1 to 7.3m2/1] of surface area. This coverage rate should result in 1 to 1.5 dry mils [25.4 to 38 dry microns]. Surface profile and application conditions will affect coverage rate.

Consult Technical Service for minimum dry mils thickness recommendations when steel surfaces are sandblasted to a surface profile greater or less than 2 mils.

Spray gun should be held not more than 24" from, and at a perpendicular angle to the surface being primed. As PRIMER 302 is an ultra-fast drying primer, it will begin to dry, or "powder" if the spray gun is held too far away from, or at a severe angle to the surface. Primer which is powdered onto a substrate does not wet into the surface adequately to achieve proper adhesion. Powdering exhibited on particular PRIMER 302 applications can be eliminated by thinning with up to equal parts of M.E.K.

When PRIMER 302 is applied over stainless steel or aluminum, apply primer to a small test area to ensure proper adhesion. Due to the various types of stainless steel and aluminum, preparation of the surfaces to receive PRIMER 302 may require a different procedure from than that stated above. For any primer to function as it was designed, proper surface preparation is essential in attaining optimum adhesion.

PRIMER 302 should be topcoated on the same day. If topcoating can not be achieve within 48 hours, consult Technical Service for recommendations.



CLEAN UP
Clean equipment with Methyl Ethyl Ketone (MEK).



LIMITATIONS & PRECAUTIONS
PRIMER 302 Part B component is affected by moisture prior to catalyzation and must be protected from moisture contamination. Keep all containers tightly closed during storage. Containers are factory sealed with an inert gas to prevent contamination. After opening and if all components are not to be used, containers must be purged with nitrogen gas or dry air and tightly sealed.

Solvents are flammable. Use only in a well ventilated area. Keep away from heat, sparks, open flame and lighted cigarettes. Use explosion-proof application equipment.

Avoid prolonged or repeated breathing of vapor or spray mist. Approved (MESA/NIOSH) chemical cartridge respirators should be worn by applicator. Avoid contact with eyes and contact with skin.

For additional information on safety requirements, refer to OSHA guidelines and PRIMER 302 Material Safety Data Sheet.




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