Sika

Sikaflex® NP 1, 10oz, Polyurethane Sealant

Sikaflex® NP 1, 10oz, Polyurethane Sealant

$98.79 - $189.79
  • SKU: SIK NP1-MXP
  • Availability: Same Day Shipping Applies Monday to Friday if Ordered by 2 PM EST.
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Availability: Same Day Shipping Applies Monday to Friday if Ordered by 2 PM EST.
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Description

Sikaflex® NP 1 is a one-component, high-performance, moisture-curing polyurethane sealant formulated for a wide range of construction and acoustical applications. It requires no mixing and typically no priming, making it a fast and reliable choice for sealing and bonding interior and exterior joints. Once cured, it forms a tough, flexible rubber that withstands weather, movement, and water exposure. Sikaflex® NP 1 also acts as an acoustic sealant, reducing sound transmission in partition systems and helping achieve higher STC ratings

Features & Benefits

  • No Mixing Required: One-component, gun-grade formula simplifies use
  • ±35% Joint Movement: Excellent elasticity for dynamic joints
  • Non-Sag: Ideal for vertical and overhead applications
  • Acoustic Rated: Improves sound transmission class (STC 44, ASTM E90)
  • Water Immersion Safe: Approved for wet areas with proper primer
  • Interior & Exterior Use: Functions in above- and below-grade conditions
  • Wide Temp Range: Applies from -40°F to 180°F
  • Adheres to Many Substrates: Concrete, aluminum, masonry, wood, natural stone, tile
  • Paintable: Compatible with non-rigid coatings
  • Fire Resistant: UL classified; passes 4-hour fire and hose stream test
  • VOC Compliant in All 50 States: Meets strict regulatory requirements

Technical Data

Property Value
Movement Capability ±35% (ASTM C719)
Elongation at Break 800% (ASTM D412)
Tear Strength 50 pli (ASTM D1004)
Sound Transmission (STC) 44 dB (ASTM E90)
Shrinkage None
Cure Time Skins overnight; full cure ~1 week; immersion 21 days
Service Temperature −40°F to +180°F
Adhesion in Peel 30 lbs (ASTM C794) – primed for immersion
Shelf Life 1 year (cartridges & ProPaks)

Recommended Applications

Sikaflex® NP 1 is suitable for both horizontal and vertical joints in demanding environments:

  • Expansion joints
  • Control joints
  • Precast concrete panels
  • Roofing components and flashing
  • Storefronts and window/door frames
  • Stucco, masonry, siding joints
  • Fascia and parapets
  • Wet environments (with appropriate primer)

Common Substrates:

  • Concrete (including green concrete after 72 hrs)
  • Masonry (stone, brick, block)
  • Wood (weathered or treated)
  • Aluminum
  • Clay & concrete roof tiles
  • Natural stone
  • Vinyl and stucco siding
  • Metal surfaces (with primer)

Application Details

Surface Preparation

  • Ensure surfaces are structurally sound, clean, and dry
  • Remove oil, grease, old sealant, and curing compounds
  • For porous substrates, abrasive prep (e.g., grinding or brushing) is recommended
  • Primer required for immersion, green concrete, metals, or questionable adhesion situations (Sikaflex® Primer-173)

Joint Design

  • Recommended joint depth: ¼"–½"
  • Use backer rod or bond breaker to control depth and prevent 3-point adhesion
  • Follow SWRI guidelines for proper joint geometry

Application

  • Use standard professional-grade caulking gun
  • Fill joints from bottom up to avoid air pockets
  • Tool immediately for best adhesion and clean finish
  • For roofing tiles, apply sealant bead to the upper surface of the downslope tile and press upslope tile into place

Cure Time

  • Skins within 24 hrs
  • Full cure ~7 days (longer in cold/humid conditions)
  • Allow 21 days for immersion use
  • Paintable after full cure (adhesion test recommended)

Cleanup

  • Clean uncured sealant with xylene
  • Remove cured material mechanically