Topcoat #7 is an aliphatic two-component polyurethane clear coat that is formulated for exterior applications over flexible polyurethane or polyurea substrates. In addition, Topcoat #7 and has excellent long term gloss and color retention. Topcoat #7 may be used in combination with high build for exterior or interior industrial maintenance and product finishing where corrosion resistance and excellent long term protection are important. The flexibility of Topcoat #7 is inherent in the basic polymer and not achieved by the use of plasticizers; therefore, the coatings are not subject to embrittlement with age.

Features:

  • Environmental Resistance: provides excellent resistance to corrosion, abrasion, chemicals and impact.
  • Versatility: TopCoat #7 may be also be used on various metal substrates, wood, plastics and concrete.
  • Application Ease: applied via conventional air assist or airless spray or brush.

Application and Mix Ratio

TopCoat #7 may be applied via most methods of spraying by brush applicator. Optimum conditions for TopCoat #7 are 77˚F (25˚C) and 50% relative humidity. There are times when there is not enough moisture to cure moisture-curing polyurethane at a reasonable rate. Any climate conditions, with lower humidity will retard cure resulting in reduced properties. 100 – 200 ft2 per gallon for 5.5 to 11 dry mils, depending on porosity, roughness of surface, and product color.

TopCoat #7 is best applied between ambient temperatures of 70˚F - 95˚F. The substrate temperature must be at least 5˚F above the dew point. Two to three hours minimum at room temperature 77˚F (25˚C) when adequate humidity and good air circulation are available. For maximum inter-coat adhesion, re-coat within 24 hours. The use of Industrial Polymers TopCoat 9 Accelerator or heat will shorten re-coat times.

TopCoat #7 is tack free in 2 - 3 hours and dries hard in 24 hours under 77˚F and 50% R.H. conditions. Room temperature cures of 24 hours permit light use. The coatings are usually suitable for normal use in 48 to 72 hours but continue to develop full properties for the following three weeks. At cool temperatures (below 60˚F) and/or low humidity (below 40%) the addition of an accelerator may be required.

TopCoat 9 Accelerator may be used to accelerate cure if acceptable curing conditions exist. Co-reactant TopCoat 9 Accelerator may be used in the last topcoat when superior chemical resistance is required. This accelerator also provides accelerated cure in low temperature or low humidity conditions.

TopCoat #7 should be thinned with Methyl Amyl Ketone (M.A.K.) to insure a smooth surface.

Prime 460 SPX (Two Component) Old elastomer surfaces or blasted steel surfaces. Proper surface preparation and priming are required in order to obtain the long-term protection that TopCoat #7 provides.

TopCoat #7 may be tinted just prior to use through the addition of SL- Pigment concentrates, which are compatible with the urethane coating. A maximum of 25% by weight of pigment can be used with activated Topcoat # 6

The TopCoat #7 coatings cure or polymerize to high molecular weight films by chemical reaction and partial reaction with the moisture in the air. The by-product of this reaction is carbon dioxide (CO2), a gas. This reaction begins even before the solvent is completely evaporated.

In cooler weather or where faster curing times are needed, the TopCoat 9 Accelerator can be added to speed up drying and "tack free" times.

The following additions are recommended; higher additions of TopCoat 9 Accelerator are not recommended as it may cause premature "yellowing" in the cured product and reduce resistance to long term weathering.

Add to the TopCoat Component B before combining with Component A.

Component B

TopCoat 9 Accelerator Addition

1 Pint ( 0.95 kg)

1 cc (1 gram )

1 Quart ( 1.90 kg )

2 cc ( 1 gram )

1 Gallon ( 3.80 kg )

4 cc ( 4 grams )

5 Gallons (19.0 kg )

20 cc ( 20 grams ) 

 

Properties

Working Properties

Mix Ratio By Weight

97.41 parts A/ 100 part B

Mix Ratio By Volume

100 parts A/ 100 parts B

Viscosity @ 72°F (Component A) Brookfield Viscometer

1609 cps (Spindale LV 3 @ 12 rpm)

Viscosity @ 72°F (Component B) Brookfield Viscometer

34 cps (Spindale LV 3 @ 12 rpm)

Viscosity @ 72°F (Mixed) Brookfield Viscometer

389 cps (Spindale LV 3 @ 12 rpm)

Color

Mixed:

Clear

Working Life @ 72°F

2-3 hours

Cure Time* @ 72°F

24 hours

*Cure time depends on temperature and relative humidity.

 

Physical Properties

Specific Gravity: (Part A)

0.98

Specific Gravity: (Part B)

1.01

Specific Gravity: (Mixed)

0.99

Weight/Gallon Part A

8.17 lbs.

Weight/Gallon Part B

8.38 lbs.

Weight/Gallon Mixed

8.27 lbs.

VOC Content per mixed liter

 

Hardness @ 72° F

ASTM 2240

75 Shore A

Tear Strength

ASTM D-624

1025 lb/in

Tensile Strength

ASTM D-412 die C

3630 psi

Elongation

ASTM D-412 die C

124%

 

Chemical Resistance

The following data illustrates the excellent chemical and solvent resistance of TopCoat #7 when used with the appropriate primer. Chemicals, which will attack urethane coatings, are strong oxidizing acids like nitric and chromic as well as some organic acids such as acetic at concentrations of 5% or higher. Also, some acids will cause color changes in certain green, yellow, orange, red and tan coatings.

TopCoat-7-Chemical-Resistance

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Clean Up

TopCoat #7 may be cleaned up with toluene, MAK or laquor thinner, which will facilitate removal of cured urethanes. Dispose of all empty TopCoat #7 component containers in accordance with local, state and federal regulations. Empty component containers can be rendered non-hazardous by rinsing the containers with a small amount of mixed material and allowing the solvents to evaporate. The containers will then contain non-hazardous cured urethane.

Storage and Shelf Life

TopCoat #7 components are shipped from the factory in sealed containers that are purged with dry nitrogen. The containers should be kept tightly sealed and stored in a cool and dry area that is protected from direct sunlight and moisture. Storage temperatures should not exceed 80°F. Shelf life of factory sealed containers stored under these conditions is six (6) months, Component B may significantly "yellow" over time. Containers that have been opened should be resealed immediately after material has been removed in order to prevent moisture contamination and solvent evaporation. Resin component containers should be purged with dry nitrogen if the contents are not used within 24 hours after opening.

Shipping

Shipping Class: Class 92.5 Hazardous