Chemical Resistant Sealants - Sika® Duoflex NS

Two Component, Non-Sag, Polysulfide Sealant

Sika® Duoflex NS is a two component, non-sag, premium quality polysulfide sealant, specifically designed for vertical and overhead surfaces.

• Tough, elastic, rubber-like seal.
• Remains flexible with expansion and contraction of building component without adhesive or cohesive failure, based on good joint design.
• Stays resilient within a wide temperature range.
• Excellent resistance to water, oils, grease, most solvents, mild acids and alkalis.
• Tenacious adhesion to concrete, metal, wood, glass, stone, ceramic and masonry surfaces in any combination, typically without the need for priming with Sika® Duoflex Primer-5050.
• Effective under constant immersion or saturated conditions, when suitably primed with Sika® Duoflex Primer-5050.

Usage

Sika® Duoflex NS may only be used by experienced professionals. Sika® Duoflex NS is suitable for either exterior or interior use to seal both static and dynamic joints:

• Joints in precast concrete
• Joints in and around swimming pools
• Joints within primary and/or secondary containment areas
• Joints in glass and metal curtain wall construction
• Expansion and control joints in concrete and masonry walls and ceilings
• Joints in metal siding
• Perimeters of aluminum window frames and metal panels
• Joints located in gas station and refueling environments

Advantages

• Tough, elastic, rubber-like seal.
• Remains flexible with expansion and contraction of building component without adhesive or cohesive failure, based on good joint design.
• Stays resilient within a wide temperature range.
• Excellent resistance to water, oils, grease, most solvents, mild acids and alkalis.
• Tenacious adhesion to concrete, metal, wood, glass, stone, ceramic and masonry surfaces in any combination, typically without the need for priming with Sika® Duoflex Primer-5050.
• Effective under constant immersion or saturated conditions, when suitably primed with Sika® Duoflex Primer-5050.

Packaging

1.5 gallon (5.7 liter) unit with both Components 'A' and 'B' contained in a pail; 60 units per pallet

Color

Component 'A': Gray liquid / Component 'B': Gray liquid

Components 'A' and 'B' mixed: Bronze (i.e. Brownish Gray) non-sag sealant

Product Details

Sustainability / Certifications / Approvals

APPROVALS / STANDARDS

• Sika® Duoflex NS meets ASTM C920, Type M, Grade NS, Class 25, Use T₂ (requiring appropriate total recessed joint design considerations), NT, I, A, G, M and O.
• Compliant with NSF/ANSI 61 "Drinking Water System Components - Health Effects" for potable water contact after full cure (reference: IAPMO R&T File No. K-12483).

Product Information

Shelf Life

12 months from date of production if stored properly in original, unopened and undamaged, sealed packaging.

Storage Conditions

Store in cool, dry, well ventilated conditions, out of direct sunlight at 40 - 95 °F (4 - 35 °C).
Precondition Components 'A' and 'B' to 65 - 75 °F (18 - 24 °C) before mixing and application.

Technical Information

Abrasion Resistance

Excellent

Resistance to Static Puncture

Excellent

Chemical ResistanceUV Exposure

Very good

Colour stability

Very good

Service Temperature

- 40 to 170 °F (- 40 to 77 °C) when fully cured

Application

Application Information

Mixing Ratio

Mix entire unit. Do not batch down.

Ambient Air Temperature

40 - 100 °F (4 - 38 °C) Sika® Duoflex NS should be installed when joint is at midrange of its anticipated movement.

Substrate Temperature

40 - 100 °F (4 - 38 °C) Sika® Duoflex NS should be installed when joint is at midrange of its anticipated movement.

Substrate Moisture Content

Beware of surface condensation! To avoid dew point conditions during application, substrate temperature must be at least 5 °F (3 °C) above measured dew point temperature.

Application Steps

SUBSTRATE PREPARATION

All joint surfaces must be clean, sound, free of contaminants, dust-free, dry and frost-free. Interior joint surfaces must be free of oils, grease, paints, coatings, sealers, curing compound residues, rust and any other foreign matter that might prevent good adhesion. Ideally substrate preparation should be accomplished by mechanical means (e.g. sandblasting, abrasive grinding, etc.). Mask off and protect any adjacent surfaces (e.g. edges of joint) that should not receive contact with Sika® Duoflex NS. Closed cell backer rod or bond breaker tape must be installed at the bottom or base of the joint prior to sealant installation to prevent three sided adhesion. Closed cell backer rod diameter should be slightly larger than actual width of joint to provide a friction fit and adequate sealant support.

Joint Design: Proper joint design for moving joints is 2:1 width to depth ratio (typical), with a recommended 1/4 inch (6 mm) minimum and 1/2 inch (13 mm) maximum depth of sealant. For nonmoving joints, the width to depth ratio can vary. Consult with Sika Technical Services for unusual joint configurations.

Priming: For maximum adhesion and/or when the fully cured sealant will be placed into Immersion service applications, the use of Sika® Duoflex Primer-5050 is necessary. Sika® Duoflex NS should completely cover primed surfaces. Consult with Sika Technical Services if unsure whether use of the primer is necessary. A uniform, glossy sheen appearance typically indicates adequate priming. Some surfaces, such as porous concrete, may require two coats of Sika® Duoflex Primer-5050. Primer must be Tack Free (i.e. dry to the touch) before applying sealant. Sealant must be applied same day as primer. Primed surfaces that have not received sealant and left overnight should be re-primed.

MIXING

Place entire contents of Component 'B' into pail of Component 'A' and mix using a low speed rotary drill (100 - 300 rpm) and appropriate sealant mixing paddle (reference Sika product code: 108142). Mix for 3 to 5 minutes to achieve a uniform color, appearance and consistency. Scrape down sides of pail periodically during the mixing procedure. Avoid entrapment of air during mixing. Mixed material must be used within the published Pot Life. Do not attempt to thin or use material that has already started to harden and cure. The individual components are formulated, manufactured and shipped to be used together.

When mixing in colder temperature conditions [i.e. < 50 °F (10 °C)], be careful not to force the sealant mixing paddle to the bottom of the pail. After adding Component 'B' to Component 'A', mix the top 1/2 to 3/4 of the pail's contents during the first minute of mixing. After scraping down the sides of the pail, mix again for another minute. The sealant mixing paddle should reach the bottom of the pail between the first and second minute of mixing. Scrape down the sides of the pail a second time and then mix for an additional 2 to 3 minutes until sealant components are well blended to a uniform color, appearance and consistency.

CLEANING OF TOOLS

Uncured material can be removed from surfaces with an approved solvent (e.g. Acetone, MEK or Xylene). Equipment should be cleaned immediately after use. Strictly follow solvent manufacturer's warnings and instructions for use. Cured material can only be removed from surfaces by mechanical means.

See More

See Less