By Siway Sealants — Professional PU Sealant & Adhesive Manufacturer
Polyurethane (PU) sealants and adhesives have become essential in modern construction, transportation, and manufacturing industries due to their outstanding elasticity, strong adhesion, and chemical resistance. As a leading manufacturer of silicone and polyurethane products, Siway Sealants provides a full range of PU sealants, PU adhesives, PU foam, and PU waterproof coatings designed to meet international standards and regional requirements.
Whether for concrete joints, metal bonding, façade sealing, or waterproofing systems, Siway’s PU series delivers reliable performance under the most demanding environmental conditions.
1. What Is Polyurethane Sealant & Adhesive?
Polyurethane sealants and adhesives are one- or two-component polymers that cure with moisture to form flexible yet durable elastomers.
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--Sealants are used to fill and protect joints from air, moisture, and contaminants.
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--Adhesives bond materials permanently with high mechanical strength.
Unlike silicone sealants, polyurethane offers superior mechanical bonding to porous substrates such as concrete, brick, and wood — making it ideal for construction and industrial assembly.
2. Chemical Composition and Working Principle
PU sealants are composed of:
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--Polyols (flexibility and elasticity)
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--Isocyanates (reactivity and cross-linking)
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--Additives & Catalysts (enhance curing, adhesion, and durability)
When applied, PU reacts with ambient moisture to form a tough, elastic polyurethane polymer network, ensuring a waterproof and flexible joint capable of absorbing structural movement.
3. Polyurethane vs Silicone vs MS Polymer Sealants
| Property | Polyurethane (PU) | Silicone | MS Polymer |
|---|---|---|---|
| Adhesion to porous materials | Excellent | Moderate | Good |
| Tensile strength | High | Medium | Medium |
| UV resistance | Moderate | Excellent | Good |
| Paintability | Yes | No | Yes |
| Chemical resistance | High | Very high | Good |
| Movement capability | ±25% | ±50% | ±25% |
| Cost-performance ratio | ★★★★★ | ★★★★ | ★★★★ |
--For curtain wall or glazing applications, choose Siway Silicone Sealants
--For concrete, flooring, or metal joints, use Siway Polyurethane Sealants.
4. Key Advantages of Siway Polyurethane Series
Strong Adhesion on Diverse Substrates
Adheres to concrete, metal, wood, glass, ceramic, and plastics without primers.
Excellent Mechanical Strength
High tensile and shear resistance ensures long-term performance under heavy stress.
Paintable & Sandable
Unlike silicone, cured PU sealant can be painted over for aesthetic finishes.
Weatherproof & Waterproof
Provides outstanding resistance to rain, vibration, and temperature changes.
VOC-Compliant & Eco-Friendly
Low-VOC, solvent-free formulations meet REACH, RoHS, and GB18583 standards.a
5. Siway Polyurethane Product Line Overview
| Product | Description | Application |
|---|---|---|
| Siway PU Sealant | High-strength, flexible joint sealant | Building façades, expansion joints, precast concrete |
| Siway PU Adhesive | Structural-grade adhesive | Metal, wood, and composite bonding |
| Siway PU Foam | Expanding foam insulation and gap filler | Window and door installation, thermal insulation |
| Siway PU Waterproof Coating | One-component liquid-applied waterproofing membrane | Roofing, basements, tunnels, and bathrooms |
Each product is tested according to ASTM C920, ISO 11600, and GB/T 14683 standards to guarantee durability and consistency.
6. Major Industrial Applications
Construction and Civil Engineering
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--Expansion joints and concrete sealing
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--Flooring systems and precast panels
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--Tunnel and bridge waterproofing
Automotive and Transportation
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--Vehicle body assembly and vibration damping
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--Windshield bonding and cabin sealing
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--Railway and marine applications
Residential and Interior Use
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--Door and window frame sealing
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--Wooden flooring and furniture bonding
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--Bathroom waterproofing and tiling
7. Common Problems and Professional Tips
| Problem | Cause | Solution |
|---|---|---|
| Bubbling | Moisture contamination during curing | Apply in dry conditions, control humidity |
| Poor adhesion | Dirty or oily surface | Clean and prime before application |
| Cracking | Excessive joint movement | Choose high-flexibility PU or hybrid |
| Yellowing | UV exposure | Use Siway UV-resistant PU formulation |
8. Environmental Sustainability and Compliance
Siway’s PU products are developed under the company’s Green Manufacturing Program, using low-VOC, non-toxic, and solvent-free formulations.
They comply with:
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--LEED & BREEAM green building credits
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--REACH and RoHS European standards
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--GB 18583 (Chinese Indoor Air Quality)
This commitment ensures performance with minimal environmental impact.
10. Why Choose Siway Sealants
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--Over 30 years of manufacturing expertise
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--Certified under ISO 9001, ISO 14001
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--Exported to 80+ countries
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--Complete product portfolio: Silicone, Polyurethane, MS Hybrid, Fireproof, and Structural Sealants
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--Expert technical support and OEM/ODM services
FAQ
Q1: What is the main difference between polyurethane and silicone sealants?
A1: Polyurethane sealants bond better to porous materials and can be painted, while silicone sealants offer better UV and weather resistance.
Q2: Can polyurethane sealant be used outdoors?
A2: Yes, high-quality polyurethane sealants like Siway’s are ideal for outdoor applications including façades, bridges, and concrete joints.
Q3: Is Siway PU sealant environmentally friendly?
A3: Yes, Siway’s PU formulations are low-VOC, solvent-free, and compliant with LEED, REACH, and RoHS standards.
Q4: Can I use PU adhesive for metal bonding?
A4: Absolutely. Siway’s PU adhesives offer high tensile strength and flexibility, perfect for metal, composite, and wood assemblies.
Post time: Oct-30-2025