Polysulphide Sealant Techseal RDL 940

RDL-940 (Gun Grade) is a non-sag material used for sealing of horizontal, vertical & ceiling joints.

DESCRIPTION

POLYSULPHIDE SEALANT TECHSEAL 
TECHSEAL RDL 940 are two component sealant based on ‘THIOKOL’ – Polysulphide liquid elastomer. It consists of a ‘base’ compound and ‘accelerator’ (Curing Agent). When the two
components are mixed together prior to application, a chemical reaction is initiated which cures instantly to a firm, flexible rubber like seal with excellent adhesion to concrete, masonry,
wood, glass, acrylic and PVC plastics. It is capable of withstanding repeated extension, compression & cyclic movements without the loss of adhesion and resists deterioration by weathering, sunlight, ozone, water, salt, oils and fuels. It is far superior to all the conventional joint sealing material like bitumen, mastics, metallic channels and expansion sheets.

FEATURES / ADVANTAGES

•  Cures at ambient temperatures to a tough, elastic and flexible rubber like material
•  Bonds strongly to most of the building materials with the use of recommended primers
•  Durable, remains unaffected by UV rays, ozone and weathering conditions
•  Resistant to water, salt water, 10% dil. acids except nitric acids, alkalis, most of the common chemicals, vegetable, lubricating oils and fuels
•  Performs well in a temperature ranging from –20⁰C to 80⁰C
•  Slip resistant (sag) can be applied in horizontal joints
•  Movement capability – Provides satisfactory hermetic sealing of the joint subjected to expansion, contraction, vibration and cyclic movement within the following limits. -Movement joints up to ± 25% of the width
•  Slip resistant (non-sag) can be applied in vertical & ceiling g joints
•  Self leveling, after pouring in horizontal joint levels itself
•  Resilient. Recovers the original width after expansion & contraction without loosing the surface bond
•  Excellent reparability property
•  It can be over coated by waterproofing compounds
•  Non-toxic
•  Sealant will not cause staining to concrete masonry or stones

TYPICAL APPLICATION

•  Sealing of expansion, contraction & construction joints in building structures such as, basements, subways, retaining walls, floors, external walls and claddings of high-rise buildings, roof terraces & ceilings especially structural expansion joints running through the ceiling
•  Sealing of dynamic structural cracks
• Glazing joints of window, door frame and curtain walls
•  Joints & ‘J’ bolts of asbestos sheet roofing
•  Sealing of water retaining structure joints such as, water tank, reservoir, dams, aqua ducts, canals, culverts and water treatment plant
•  Sealing of joints in traffic areas such as, bridges, roads and car parking areas

JOINT DESIGN

In building structures various (different) types of joints are designed such as Butt joints, Lap joints, Fillets Joints, Expansion joints, Control joints and Glazing joints. As the joint expand, contract or experience a shear movement, cyclic movements, sealant changes the shape accordingly, but the volume of sealant remains same. Hence, in designing the joints, it is vital that the proper width-to-depth ratio is specified so that the width of the joint is consistent with the capability of the sealant to endure daily and seasonal cycles for prolonged periods. The amount of movement in a joint is dependent on the length (span), the coefficient of linear expansion of a panel section and the temperature differential of the substrate. To achieve the long-tem, effective performance the established width-to-depth ratios are determined and are given below:-

BACK UP MATERIALS

Insert compressible polyethylene, polyurethane, neoprene, polyethylene butyl rod as backup material to control depth of sealant in the joint and to provide support for tooling of the sealant.

PRIMING

Select a primer suitable to the substrate and apply two coats by brush on the sides of the joints surface at an interval of 30 minutes.

•  Primer RDL 942 : For porous substrate such as concrete, wood etc.
•  Primer RDL 947 : For non-porous substrate such as metals, glass etc.
•  Primer RDL 952 : For acrylic glass
•  Primer RDL 948 : For PVC plastic & rubber

BOND BREAKER

Fix bond breaker tape such as self adhesive polyethylene tape on back-up material to avoid adhesion of sealant to the third surface.

MIXING

The base and accelerator compounds are packed in pre-weighed quantity as per the mixing ratio. After the application of primer, mix the material of individual container. Transfer entire quantity of accelerator to the base compound tin and mix it thoroughly to a uniform, homogenous black color. Mixing can be done manually with spatula, palette knife or special flat stirrer attached to a low speed electric mixer less than 500 r.p.m.

APPLICATION

Apply the mixed gun grade compound by means of a spatula or by filling into a plastic cartridge which is then placed into the hand held caulking gun into the joint.

TOOLING AND FINISHING

It is desirable that a smooth surface is obtained. Tool the sealant by pressing the puffy knife or flat tool against the sealant surface, moving along the length of the joint. Tooling breaks air
bubbles and exposes any air pockets present. Tooling compresses the sealant, thus promoting adhesion to the joint sides. After tooling the masking tape should be removed immediately.
Soap solution can be used to smoothen the sealant surface.

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