KYK Megaİzo PU Mastik HM S492

High Modulus, Permanently Elastic Polyurethane Joint Sealant Solution

Selecting the right sealant in floor and façade applications exposed to intense joint movements plays a critical role in maintaining long-term water and air tightness as well as preserving structural integrity.

KYK Megaİzo PU Mastik HM S492 is a professional polyurethane-based joint sealant with a high modulus structure and permanent elasticity. It is designed for heavy-duty applications such as parking areas, bridges, tunnels, industrial floors, and façade details. Thanks to its moisture-curing formulation, it provides strong adhesion, does not shrink, works compatibly with different surfaces, and can be easily applied with a sealant gun.

Outstanding Features

Permanent Elasticity

Provides long-term flexibility against joint movements and minimizes the risk of cracking and separation.

High Modulus and Durability

Suitable for pedestrian and vehicle traffic areas. It can be safely used in parking lots, pavements, ramps, and industrial floors.

Wide Surface Compatibility

Provides strong adhesion on various surfaces including:

• Concrete
• Cement-based plaster
• Ceramic tiles
• Marble
• Natural stone
• Wood
• Aluminum
• PVC
• Galvanized sheet metal
• Glass

Resistance to Water and Weather Conditions

Provides long-lasting performance in exterior façade applications and wet area details.

Paintable Structure

Can be painted after compatibility testing.

Practical Application

Thanks to its 600 ml sausage packaging, it enables fast, clean, and practical application with a sealant gun.

Application Areas

Movement Joints

• Floor expansion and movement joints
• Parking lots and ramp applications
• Pedestrian walkways

Heavy-Duty and Infrastructure Applications

• Bridge structures
• Tunnel and dam joints
• Concrete roads
• Irrigation channel connection points

Waterproofing Details

• Cracks and gaps in reinforced concrete water tanks
• Roof, rain gutter, and downpipe connections
• Chimney base details

Façade and Interior Finishing Applications

• Block joint gaps
• Wall–floor connections
• Door and window frame edges

Industrial Facilities

• Structural joint sealing applications in food and pharmaceutical production areas

Note: On mineral surfaces such as concrete, plaster, and ceramic, it is used for expansion and movement joint applications. On surfaces such as aluminum, PVC, galvanized steel, plastic, and glass, it can be used for installation and sealing purposes.

Technical Performance Values

Thanks to its high elongation capacity and balanced modulus value, KYK Megaİzo PU Mastik HM S492 adapts to joint movements while maintaining reliable sealing performance.

Its Shore A 40 ± 5 hardness class provides optimum elastomeric behavior, creating a balanced structure that is neither excessively rigid nor overly soft.

Surface Preparation

Proper surface preparation is essential for achieving a successful and long-lasting application.

Cleaning

Joint edges must be dry, sound, and free from dust, oil, dirt, and loose particles.

Moisture Level

Surface moisture should not exceed 5%.

Primer Application

The product provides high adhesion without primer on most surfaces. However, for surfaces exposed to high mechanical loads or surfaces that cannot be completely cleaned, a suitable PU or epoxy primer is recommended.

Joint Backing Rod Usage

For deep joints, the use of closed-cell backing rods is recommended. This prevents three-sided adhesion and significantly improves the service life of the sealant.

Application Steps

1. Apply masking tape along the joint edges for a clean and straight finish.
2. Place the 600 ml sausage cartridge into a suitable sealant gun.
3. Cut the nozzle tip at approximately a 45° angle.
4. Apply the sealant continuously along the joint.
5. Smooth the surface with a spatula and ensure full contact with the edges.
6. Remove masking tape before skin formation occurs.
7. Protect the application from water contact for the first 24 hours.
8. Application temperature should be between +5°C and +35°C. Do not apply on frozen or thawing surfaces.

Consumption Calculation

Consumption depends on joint width and depth.

Examples (for 100 meters of joint):

Practical calculation method:

Cross-sectional area (mm²) × 0.1 ≈ ml / meter

Consumption can be quickly calculated based on the 600 ml packaging size.

Packaging and Storage

The product should be stored away from direct sunlight in unopened packaging. Opened cartridges should be used without delay.

Cleaning

Before curing, tools and surfaces can be cleaned with acetone or alcohol. After curing, mechanical cleaning methods are required.

Professional Application Recommendations

• Avoid three-sided adhesion; use proper joint geometry.
• Always perform a compatibility test before painting.
• Protect the application from water and rain during the first 24 hours.
• Apply immediately after opening the cartridge.

Frequently Asked Questions

Can it be painted over?

Yes. However, a preliminary compatibility test is recommended.

Is primer required?

Primer is recommended for high-load applications or surfaces that are difficult to clean.

How can joint depth be controlled?

By using a closed-cell backing rod.

What is the curing time?

The curing rate is approximately 2 mm per 24 hours. Skin formation occurs within 60–90 minutes. Several days may be required to achieve full mechanical strength.

Is it suitable for exterior façade applications?

Yes. It is resistant to weather conditions and water. However, it should be protected during the first 24 hours after application.