Flexible polyurethane (PU) foams are widely used in a variety of industries, from mattress and furniture manufacturing to automotive components, due to their exceptional comfort, strength and durability properties. The choice of the appropriate PU system and the production process, continuous or discontinuous, are critical factors that directly affect the quality of the final product. Among the most popular systems for the production of flexible foams are HR (High Resilience), Conventional Flexible, Viscoelastic and Hypersoft, each with specific advantages depending on the type of production.
In this article, we will explore in detail the characteristics of each of these systems and the advantages they offer in the different production processes of flexible PU foams.
Continuous and Discontinuous Process in the Production of Flexible Foams
Before discussing each PU system, it is important to understand the two main flexible foam production processes: the continuous process and the batch process.
- Continuous Process: Used when there is a need to produce large volumes of foam uninterruptedly, such as in the manufacture of foam blocks that can later be cut for various applications. This method is highly efficient in terms of time and cost, ideal for the production of mattresses, upholstery and other large-scale products.
- Batch Process: In this method, the foam is molded into a rectangular or cylindrical block, which is suitable for the production of customized parts, such as automotive seats, pillows and ergonomic components. This process allows greater control over the geometry of the final product and is more flexible for small production runs or parts with complex shapes.
Then there is the injection process that begins with the mixing of two main components: polyol and diisocyanate, which react chemically to form polyurethane foam. Catalysts, blowing agents and additives are also included to control the reaction time, density and other properties of the foam. The mixture is injected into closed molds under high pressure.
After injection, the foam expands inside the mold due to the release of carbon dioxide (CO₂) as a result of the chemical reaction with water or another blowing agent. This process creates the cellular structure of the foam, which is responsible for its flexibility and resilience. Depending on the formulation and curing time, the injected part can be removed from the mold in a few minutes.
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Therefore, we have different PU systems, each with its advantages in continuous and discontinuous processes.
PU HR (High Resilience) system
The HR, or High Resilience, PU system is known for its excellent elasticity and durability properties. This system is widely used in products that require a quick return to their original shape after compression, such as car seats, high-performance mattresses and premium upholstery.
In the continuous process, the HR system offers a great advantage for the production of large blocks of foam intended for the manufacture of high-quality mattresses and upholstery. Its main feature is its high recovery capacity, which provides products with superior durability and high comfort. Continuous production allows this material to be used on a large scale with high consistency in density and physical properties, ensuring that all products, regardless of size, offer the same resilience and comfort performance.
In the discontinuous process, the HR system is particularly advantageous for custom moldings, such as car seats and custom-designed furniture pieces. Molded HR foam conforms excellently to the desired shape and maintains its high resilience properties, offering exceptional comfort and durability. This system is ideal for products where premium quality and ergonomic performance are essential, ensuring that the final product has a long service life and high wear resistance.
Conventional Flexible PU System
The Conventional Flexible system is widely used due to its versatility, and is the most common type of PU foam on the market. It is used in a wide variety of products, from mattresses and cushions to automotive and home appliance parts.
The Conventional Flexible system is highly efficient for continuous production, especially in the manufacture of large foam blocks that can be cut into different shapes. The main advantage of this system is its adaptability to different densities and rigidities, allowing the production of foams with customized properties to meet the demands of different applications. In the continuous process, this system offers economical production with high speed and quality consistency, ideal for markets that require large volumes with good cost-benefit.
In the discontinuous process, the Conventional Flexible system is excellent for the production of smaller or specific parts, such as cushions, chair backs or comfort accessories. The flexibility in adjusting formulas and the ease of molding allow this foam to be customized according to the needs of each application, always maintaining good mechanical and comfort properties. This makes this system highly adaptable across a wide variety of industries.
Viscoelastic PU System
The Viscoelastic system, popularly known as “memory” foam, is famous for its body-conforming properties. This type of foam is widely used in products where comfort and pressure relief are essential, such as high-quality mattresses, pillows and ergonomic supports.
In the continuous process, the Viscoelastic system is ideal for the production of mattresses and pillows, especially in large volumes. Viscoelastic foam has a unique characteristic of slow response to pressure, which allows it to mold perfectly to the body, distributing weight evenly. In the continuous process, this foam maintains its conforming properties throughout production, ensuring uniformity in the final product and providing a superior feeling of comfort in all items produced.
In the discontinuous process, the Viscoelastic system is perfect for the manufacture of molded parts, such as anatomical pillows, backrests and ergonomic supports. The ability of this foam to adapt to different shapes and provide personalized support to specific areas of the body makes it ideal for health and wellness products, where comfort and pressure relief are essential. The discontinuous process allows the viscoelastic system to be molded into complex shapes, always maintaining its characteristic of slow recovery and conformity to the desired shape.
Hipersoft PU System
The Hipersoft system is the ideal choice for applications that require extreme softness and comfort, and is widely used in luxury furniture, premium upholstery and high-end mattresses.
In the continuous process, the Hipersoft system is advantageous in the production of large volumes of foam with an exceptionally soft touch. This system allows the manufacture of foams that offer an incomparable comfort experience, making it ideal for high-end mattresses and upholstery. Continuous production ensures consistency in quality, allowing each batch produced to maintain the desired softness characteristics, even in large volumes.
In the discontinuous process, the Hipersoft system excels in the production of molded parts for extreme comfort, such as headrests, armrests and high-end cushions. The flexibility in the process allows manufacturers to create products with unique and personalized designs, without sacrificing the softness and velvety touch characteristic of this system. Hipersoft is ideal for applications where the sensation of superior comfort is a priority, such as luxury furniture and wellness products.
Choosing the right system for production
Each of the PU systems – HR, Conventional Flexible, Viscoelastic and Hypersoft – offers unique advantages in both continuous and discontinuous production processes. The choice of the right system depends on the specific needs of each application and the production requirements. Whether producing foams for mattresses, furniture, automotive components or ergonomic products, the versatility of flexible PU foams, combined with the right production technologies, enables manufacturers to offer innovative, customized and high-performance solutions.
About Amino
Amino is a reference in formulations and development of PU raw materials. We are partners of the largest manufacturers in Brazil and South America with a modern plant with high installed capacity to serve the entire global market. We are the chemical industry with the largest mix of products for various polyurethane applications, specialized in the production of surfactant silicones, amine catalysts, liquid organic pigments, special additives, PU systems for various sectors and the most advanced technology in the CASE line (Coatings, Adhesives, Sealants, Elastomers). We have a team of specialist technicians to analyze, guide and develop exclusive solutions to offer the best success to the customer.
