Sikaflex® NP 1

• ASTM C 920, Type S, Grade NS, Class 35, Use NT, M, A, T, O* and I
• Federal Specification TT-S- 00230C, Type II, Class A
• Corps of Engineers CRD-C- 541, Type II, Class A
• Canadian Specification CAN/CGSB-19.13-M87, Classification MCG-2-25-A-N, No. 81026
• CFI accepted
• Underwriters Laboratories Inc.® classified (fire resistance only)
• ISO 11600-F-25LM • STC (sound transmission class)

* Refer to substrates in Uses

Sikaflex® NP 1 is a one-component moisture-curing polyurethane.

Cartridges and ProPaks: 1 year when properly stored.

Store in original, unopened containers away from heat and direct sunlight. Storing at elevated temperatures will reduce the shelf life. 

*Primed for water immersion dictated by ASTM C 920. Concrete and aluminum primed with Sikaflex® Primer-173. 

 The cure of Sikaflex® NP 1 varies with temperature and humidity. The following times assume 75 °F (24 °C), 50% relative humidity, and a joint ½" width by ¼" depth (13 by 6 mm). 

  
 – Skins: overnight or within 24 hours
 – Full cure: approximately 1 week
 – Immersion service: 21 days

Linear Feet Per Gallon

Meters Per Liter

TABLE 1
Joint Width and Sealant Depth

Substrates must be structurally sound, fully cured, dry, and clean. Substrates should always be free of the following: dirt, loose particles, oil, grease, asphalt, tar, paint, wax, rust, waterproofing or curing and parting compounds, membrane materials, and sealant residue.

Concrete, Stone and Other Masonry
Clean by grinding, sandblasting or wire brushing to expose a sound surface free of contamination and laitance.

Wood
New and weathered wood must be clean, dry and sound. Scrape away loose paint to bare wood. Any coatings on wood must be tested to verify adhesion of sealant or to determine an appropriate primer.
  
Metal
Remove scale, rust and loose coatings from metal to expose a bright white surface. Any coatings on metal must be tested to verify adhesion of sealant or to determine an appropriate primer.

Joint Preparation

1. The product may be used in sealant joints designed in accordance with SWR Institute's Sealants - The Professional's Guide.
2. In optimal conditions, the depth of the sealant should be ½ the width of the joint. The sealant joint depth (measured at the center) should always fall between the maximum depth of ½" and the minimum depth of ¼". Refer to Table 1.
3. In deep joints, the sealant depth must be controlled by closed cell backer rod or soft backer rod. Where the joint depth does not permit the use of backer rod, a bond breaker (polyethylene strip) must be used to prevent three-point bonding.
4. To maintain the recommended sealant depth, install backer rod by compressing and rolling it into the joint channel without stretching it lengthwise. Closed cell backer rod should be about 1⁄8" (3 mm) larger in diameter than the width of the joint to allow for compression. Soft backer rod should be approximately 25% larger in diameter than the joint width. The sealant does not adhere to it, and no separate bond breaker is required. Do not prime or puncture the backer rod.
    

Priming

Sikaflex® NP 1 is considered a nonpriming sealant, but special circumstances or substrates may require a primer. It is the user’s responsibility to check the adhesion of the cured sealant on typical test joints at the project site before and during application. Refer to product data sheet on Sika® Primer, and consult Technical Service for additional information.

2. For immersion applications, Sikaflex Primer-173 must be used.

3. For green concrete applications, Sikaflex Primer-173 must be used.

4. Apply primer full strength with a brush or clean cloth. A light, uniform coating is sufficient for most surfaces. Porous surfaces require more primer; however, do not over-apply.

5. Allow primer to dry before applying Sikaflex® NP 1. Depending on temperature and humidity, primer will be tack-free in 15–120 minutes. Priming and sealing must be done on the same day.

1. Sikaflex® NP 1 comes ready to use. Apply using professional grade caulking gun. Do not open cartridges, ProPaks or pails until preparatory work has been completed.
2. Fill joints from the deepest point to the surface by holding an appropriately sized nozzle against the back of the joint.
3. Dry tooling is recommended. Proper tooling results in the correct bead shape, neat joints, and optimal adhesion. 
4. For roof tile applications apply a bead of Sikaflex® NP 1 sufficient in size to make a bond between two tiles on the upper surface of the down slope tile. Install the upslope tile and press into the sealant bead to ensure good contact between the sealant and both tiles.

1. Immediately after use, clean equipment with SikaSwell®-990 or xylene. Use proper precautions when handling solvents.
2. Remove cured sealant by cutting with a sharp-edged tool.
3. Remove thin films by abrading.