Low Vapor Permeability Butyl Hot Melt Sealant

The Low Vapor Permeability Butyl Hot Melt Sealant is a high-performance sealing solution specially developed for applications where moisture control and airtight performance are critical. Made from high-purity butyl rubber and specialty additives, this hot melt sealant offers exceptionally low moisture vapor transmission rates (MVTR), forming a robust barrier against water vapor, gases, and environmental contaminants.

Unlike conventional sealants, this product retains long-term flexibility while delivering a highly impermeable seal that protects sensitive systems and materials from degradation due to moisture. Its thermoplastic, non-curing formula allows it to remain pliable and tacky over time, making it ideal for insulated glass units (IGUs), electronic housings, HVAC systems, and other demanding environments.

With its low vapor permeability and strong adhesion, this sealant is widely used in industries that require long-lasting air and moisture seals without the risk of drying, shrinking, or cracking.

Key Features

Ultra-Low Vapor Permeability: Effectively blocks the transmission of water vapor and gases, preserving internal insulation and preventing fogging or corrosion.

Excellent Adhesion: Strong bonding to a variety of substrates including glass, aluminum, galvanized steel, and engineering plastics.

Long-Term Flexibility: Remains elastic over a wide temperature range without hardening or becoming brittle.

Non-Curing and Reworkable: No chemical curing required. Easy to remove and reseal if necessary.

Environmentally Friendly: Solvent-free, odorless, and compliant with global VOC standards.

Weather Resistant: Performs consistently in extreme temperature and humidity conditions.

Stable Extrusion: Smooth and uniform application with no clogging or residue during automated dispensing.

Technical Specifications

Base Polymer: Butyl rubber

Density: 1.4 – 1.6 g/cm³

Softening Point: 100 – 120°C

Vapor Permeability Rate (MVTR): ≤ 0.02 g/m²·24h (ASTM E96)

Application Temperature: 150 – 190°C

Color: Black or gray (custom colors available)

Packaging: 5kg/10kg/25kg blocks; 200kg drum

Shelf Life: 12 months in original packaging

Applications

Insulated Glass Units (IGUs): Acts as a secondary seal to prevent gas leakage and moisture penetration, improving thermal insulation and product lifespan.

Refrigeration & HVAC: Seals ducts and insulation panels to maintain air-tightness and humidity control.

Electronics: Protects sensitive circuits and batteries from humidity and oxidation.

Aerospace & Automotive: Used in compartments and panels where airtight and watertight sealing is essential.

Construction Panels: Ideal for sealing composite or metal panels in curtain wall systems and facades.

Application Instructions

Surface Preparation: Clean all bonding surfaces. Remove oil, dust, and moisture before application.

Melting: Heat the sealant using a hot melt applicator to a temperature of 150–190°C.

Extrusion: Apply using an automated or manual dispensing system in a continuous bead.

Assembly: Press the substrates together immediately after application to ensure a strong bond.

Storage & Handling

Store in a dry, cool (5–30°C) environment, away from direct sunlight.

Avoid stacking excessively to prevent deformation of packaging.

Use gloves and proper safety gear when handling hot material.

Seal packaging properly after each use to prevent contamination.

Deliver,Shipping And Serving

1. Online testing

Online testing will be carried out before the finished product is packaged, and the finished product will be packaged only after it meets the relevant requirements.

2. Quality control supervision.

Quality control will be carried out again before the finished product packaging is put into storage and enters the market.

3. Application testing

Carry out full product testing, from the user's perspective, restore the product application scenario, and test its application.

4. Technical service

Application technical service provides high-quality technical services. After the product enters the market, after-sales technical service will continue to track the product usage and provide high-quality after-sales service.

FAQ – Frequently Asked Questions

Q1: What does "low vapor permeability" mean and why is it important?

A: Low vapor permeability means the sealant acts as an effective barrier against moisture and gas transmission. This is critical for insulated glass, electronics, and other applications where moisture can cause damage or performance loss.

Q2: How does this sealant compare to silicone or polyurethane sealants?

A: Unlike silicone or polyurethane, butyl hot melt sealants do not cure and remain flexible over time. They offer better vapor sealing performance, making them ideal for long-term air- and moisture-tight applications.

Q3: Is this sealant suitable for high-humidity environments?

A: Yes. It is specifically formulated to maintain its barrier properties even in high humidity or wet conditions.

Q4: Can this product be reheated and reused?

A: Yes. The sealant is thermoplastic and can be reheated without losing its original properties, provided it is not contaminated.

Q5: Does it require a primer before application?

A: For most clean and non-porous surfaces, no primer is needed. However, testing is recommended for unfamiliar or complex materials.

Q6: Will it shrink or crack over time?

A: No. It remains stable and flexible throughout its service life, with no curing shrinkage or brittleness.

Q7: Is this sealant safe for indoor use?

A: Yes. It is non-toxic, solvent-free, and emits no harmful VOCs, making it safe for use in enclosed environments.

Company Profile

Chengxin (Henan) Sealing New Material Tech Co., Ltd. is a Chinese manufacturer and supplier of insulating glass sealing materials. We have been professionally focusing on the sealing material industry for many years. With excellent product quality and a complete market service guarantee system, the company has formed a wide sales network in China. In the international market, "Chengxin" brand series products have been exported to Western Europe, America, the Middle East, Africa, Southeast Asia and other countries and regions. We look forward to becoming your long-term partner.

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