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NuFlex 331 is a primerless, non-corrosive 100% neutral cure silicone that exhibits low modulus, high adhesive qualities after cured. NuFlex 331 is a high-quality, ready-to-use silicone that has a very high level of adhesion, especially to substrates such as PVC and many plastics which have typically shown difficulty adhering with silicone sealants. NuFlex 331 is unaffected by UV and air-borne chemicals.

Utilized for multiple glazing applications where a clear, high-adhesion product is preferred. Factory-made windows as primary seal/bedding compound; window installation (especially with wood finishes); vinyl siding installation; factory and field installed metal building systems; appliance manufacturing; aircraft and automotive glazing and manufacturing.

All surfaces must be dry and frost-free, free of oil, grease, rust, dirt or other contaminants that may inhibit proper adhesion. For porous substrates, such as concrete, wire brushing or air blasting (oil-free) is recommended and for non-porous substrates, a solvent wipe (oil-free) is adequate. Most substrates do not require a primer before application of the NuFlex 331 sealant. It is recommended, however, that test samples of sealant be applied to the surface to test and verify adhesion. After preparatory work is complete, mask where necessary to avoid spillage onto adjoining surfaces. Tooling should be done immediately after sealant is applied and in one continuous motion. Masking Tape should be removed immediately after tooling is completed.
Joint Design: Joint depths should not exceed 12.7 mm(1/2”) and be no thinner that 3.2 mm(1/8”). A thin bead of NuFlex 319 will allow more joint movement than a thick bead, For perimeter sealing or expansion joint design, the ratio of joint width to sealant should be about 2:1. Polyurethane or polyethylene backer rod is recommended for deep joints and polyethylene tape for shallow joints. These materials act as bond breakers and allow the sealant to stretch freely with joint movement. Install back-up material, setting blacks, spacer shims and tapes as specified. Apply NuFlex 319 in a continuous bead to fill joint. Tool with enough pressure to push the sealant down into and against the sides of the joint. Tool the sealant applied at the sill on a slight upward angle so that moisture will not pool. Excess sealant should be cleaned from glass, metal and plastic with commercial solvent such as xylol, toluol or methylethyl ketone before sealant cures. Sealant that comes in contact with porous surfaces should be allowed to cure and then be removed with abrasion or other mechanical means.

Use in well ventilated areas and avoid breathing vapors. On contact, uncured sealant irritates eyes. Flush eyes with lukewarm water. Call physician. Avoid skin contact and do not ingest. Keep out of reach of children. For complete safety information consult Material Safety Data Sheet.

NuFlex 331 complies with the following specifications: (1) CAN/CGSB-19.3-M87, Class MCG-2-40-A-L ; ASTM C920, Type S, Grade NS, Class 25, Use NT, M, G, A, O.

NuFlex 331 Siding and Trim is available in a variety of sizes 300 ml (10.1 U.S. fl oz), 850 ml (28.6 U.S. fl oz) allplastic caulking cartridges with nozzle which fit manual or air operated caulking guns, (12 cartridges to a case). It is also available in 10 Litre (2.6 U.S. Gallon) pails, 17 Litre (4.5 U.S. gallon) pails and 200 Litre (52 U.S. gallon) drums. NuFlex 331 Siding and Trim is available in clear and white colours. Special colours are available in orders of minimum quantities upon request. For sealant coverage or yields please see the “Coverage Chart” found in the “Application tip” section of the Nuco technical binder.

Shelf-life is 12 months from date of shipment from our plant when stored in clean, dry area with temperature between 40°F to 90°F (4°C to 32°C).

NUCO Inc., warrants only that it’s product will meet it’s specifications. NUCO shall in no event be liable for incidental or consequential damage. NUCO’s liability, expressed or implied, is limited to the stated selling price of any goods found to be defective.

These values are not intended for use in preparing specifications. Spec Writers, please contact NUCO Inc. before writing specifications if any further information is required.

As Supplied
Specific Gravity 1.02
Tooling Time (50% R.H. and 25°C (77°F) – in minutes 5
Tack-Free Time (50% R.H. and 25°C (77°F) – in minutes 20
As Cured
Hardness (ASTM C 661, Shore A) 16
50% Modulus (ASTM D 412, Die C) MPa (psi) 0.17 (25)
100% Modulus (ASTM D 412, Die C) MPa (psi) 0.24 (35)
Tensile Strength (ASTM D 412, Die C)MPa (psi) 1.17 (170)
Elongation at Break (ASTM D412, Die C) 600%
Tear Strength (ASTM D 624) – kN/m (ppi) 4.9 (28)
Joint Movement Capability +/-50%
Service Temperature Range (ASTM C 1299) -62 to 204°C (-80 to 400°F)
The information and data contained herein is BASED ON INFORMATION WE BELIEVE TO BE RELIABLE. Please read all statements, recommendations or suggestions herein in conjunction with our CONDITIONS of SALE which apply to all goods supplied by us. We assume no responsibility for the use of these statements, recommendations or suggestions, nor do we intend them as recommendation for any use which would infringe any patent or copyright.

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