KASTAR 963 Low Modulus MS Polymer Sealant

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Features & Benefits

KASTAR963 is a gun-grade, one component adhesive/sealant based on silane modified polymers, which cures by reaction with moisture to an elastic product. It is intended for creating flexible and high-strength
sealing and bonding joints resistant to vibration and deformation.

Used in industrial and civil construction and renovation works for sealing and filling vertical and inclined expansion and compensation seams, facade and roof joints, cracks in building panels, and roof constructions. Complies with ISO 11600 Type F Class 25 LM. Has excellent adhesion to most construction materials: stone, brick, concrete, glass, plasterboard, solid plastics (except polyethylene, polypropylene, and fluoroplastic), ceramics, aluminum, metals, composite, stainless steel, and wood. No priming is required. For indoor and outdoor works.

Application Areas

Hybrid adhesive sealant (modern analog of MS-polymers) has high operating characteristics: forms a permanently elastic high-strength and durable joint; is elastic for the whole service life; excellent for joining materials with different temperature expansion. Weather and temperature resistant. Thixotropic, does not flow or drip down the joint. After curing, it is possible to paint with aqueous and synthetic paints (in the case of solvent-based paints, run a test).

Chemical Base

Typical Physical Properties

Chemical BaseSilane Modified Polymer
Curing SystemMoisture
Density1.60 gr/ml
Appearance/ColorPaste, White, Black, Grey
Skin time10 mins
Tack free time10-20 min (23°C and %50 R.H.)
Curing rate>3.5mm/ 24 hr (23°Cand %50 R.H.)
Hardness Shore AAbout 40 – 50
Elongation at break≥300%
Tensile strength≥0.8Mpa
100% Tensile Modulus≤0.4Mpa
UV resistantNo change.
Shirkage≤ 1.5%
Service Temperature-50°C to +120°C
Application Temperature+5°C to +35°C
Shelf life12 months


  • Before the application, the tip of the cartridges is cut and a plastic cap is fixed.
  • The tip of the cap is cut according to the width of the surface and fixed to the cartridge gun.
  • For bonding application: Apply the adhesive in strips or dots to the base or on the element to be bonded. The strips must be applied in vertical rows. Bring together the parts to be joined as quickly as possible, at least within 5 minutes (this depends on the temperature and relative humidity level).
  • For sealing application: The surface of KASTAR clear applied in the joints should be smoothened with a dampene.

Application Dimentions

  • Minimum width for bonding is 1 mm.
  • Maximum width for bonding is 3 mm.
  • Minimum width for joints is 5 mm.
  • Maximum width for joints 10 mm.
  • Minimum depth for joints 5 mm.
  • Consumption (approx.)

Surface Preparation

Following cleaning procedure and materials are recommended:

  • Glass Degrease with alcohol or MEK
  • Aluminium, light alloys and stainless steel Degrease with alcohol or MEK
  • Other Metals Lightly abrade then degrease as above
  • Wood Lightly abrade surface then remove dust
  • Plastics Degrease using an agent recommended by plastics manufacturer
  • Concrete and other alkaline Surfaces Brush and remove dust


Meets or exceeds the requirements of the following specifications:

  • The requirements of VOC content specifications in LEED credit EQc4.1
  • “Low-emitting products” of SCAQMD rule 1168.
  • The French VOC requirements for class A+
  • CE marked for EN 15651 for façade & glazing applications (DOP NO: 2016-0004).


It must not be used in totally confined spaces where sealant cannot cure due to lack of atmospheric moisture.

Cannot be used on natural stone. Because the adhesion surface will discolor under influence of the sealant (looks wet) and also this is visible through the sealant due to its clear look.

Do not use in applications where continuous water immersion is possible.

Prolonged exposure to direct sunlight can cause discoloring, Joint Width 5mm 10mm Joint Depth 5mm 5mm

Efficiency /310 ml 12 meters 6 meters

Storage and shelf life

  • They should be protected from water, frost and adverse air conditions.
  • They should be kept dry and cool on wooden pallets at between +10 °C and +25 °C in moisture free conditions.
  • The opened products should be consumed immediately.
  • Shelf life is maximum 9 months conditional to complying with the aforementioned storage conditions.

Safety & Disposal

For information and advice on the safe handling, storage and disposal of chemical products, users shall refer to the most recent Material Safety Data Sheet containing physical, ecological, toxicological and other safety-related data.

The technical data contained herein is based on our present knowledge and experience and we cannot be held liable for any errors, inaccuracies, omissions or editorial failings that result from technological changes or research between the date of issue of this document and the date the product is acquired.

Before using the product, the user should carry out any necessary tests in order to ensure that the product is suitable for the intended application.

Moreover, all users should contact the seller or the manufacturer of the product for additional technical information concerning its use if they think that the information in their possession needs to be clarified in any way, whether for normal use or a specific application of our product.

Our guarantee applies within the context of the statutory regulations and provisions in force, current professional standards and in accordance with the stipulations set out in our general sales conditions. The information detailed in the present technical data sheet is given by way of indication and is not exhaustive. The same applies to any information provided verbally by telephone to any prospective or existing customer.

Chemical Base

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