Bonded Foams: What Are They?
First, let’s revisit the concept of bonded foams. After the production of foam blocks through continuous or discontinuous processes, these blocks are sent for lamination, which inevitably generates a significant amount of leftover material—commonly referred to as “scraps.”
These foam scraps can be mixed with a polyurethane bonding material (a prepolymer that binds the foam flakes) to form new bonded foam blocks.
Bonded foam blocks provide great firmness and high support capacity, making them suitable for various applications, such as mats and mattresses. Additionally, they play an environmentally friendly role by helping to reduce waste generated during the production of flexible foams.
Prepolymer Binder (Bonded Foam Adhesive)
The foam binder used in the block production process is typically a single-component adhesive with fast drying properties. It is partially volatile or non-volatile and odorless (a product without smell).
Speaking of odor, this is a critical factor when discussing foam binders. It is essential that the bonded foam adhesive is made from low-toxicity and odorless raw materials. This ensures better quality for the operator by preventing application issues and reduces costs for the company by minimizing hazards and health risks. Additionally, it is non-flammable, non-toxic, and free of harmful volatile compounds, making it safer for both the operator and the environment.
Key Features and Differentiators of “Bonded Foam Adhesive”
- Increases block firmness
- Enhances tear resistance
- Versatility: Adheres to various substrates, such as fabrics, foams, rubbers, EVA, and more.
- Fast curing speed
- Low viscosity: Facilitates easier spreading on substrates.
- High yield
- Odorless (no smell)
- MDI-based
- Sustainable: Promotes the reuse of foam scraps.
- Compliant with IMETRO standards
The secret to an excellent bonded foam adhesive lies in achieving the lowest viscosity possible (thin liquid) while maintaining undiluted (100% solid) properties. This allows the adhesive to penetrate all the foam’s pores, enabling better adhesion in bonded foam applications.
The rapid curing speed of the adhesive enhances productivity, allowing multiple mold releases in a single day.
Optimizing Production
To efficiently produce a bonded foam block, it is important to follow these recommendations:
Dosage
Use 10% to 20% of AMIPRE® (Amino’s bonded foam adhesive) relative to the total weight (kg) of the substrates.
This dosage varies depending on the amount of non-foam substrates used, such as fabrics, EVA, rubber, paper, polyethylene films, etc.
Catalyst Used
Tin Octoate: It is recommended to use 0.5% to 1.1% based on the total weight (kg) of AMIPRE®. It’s important to note that the amount of catalyst is determined by the relationship between:
- Production Speed
- Ambient Temperature
Demolding
When adhering to the correct usage conditions and procedures, bonded foam blocks can be removed from the mold within 40 to 60 minutes.
Most Common Types of Mixtures
- Integral Skin Foam
- 100% Látex
- Latex + Conventional Foam
- Fabric + Foam
- Foam 100%
- Foam + Bra Cup Padding
- Foam + EVA + Rubber
The more substrate mixtures used, the more adhesive will be required for proper adhesion of the flakes.
Manufacturing Process
Mixing
- Weighing the Flakes: By weight or volume.
- Weighing AMIPRE: 10% to 20%.
- Weighing Tin Octoate: 0.5% to 1.1%.
- Adding Tin Octoate to AMIPRE.
- Manual or mechanical mixing for 1 minute.
Process
- After mixing AMIPRE/Tin Octoate, pour it evenly over the flakes.
- The ideal mixing time for Flakes/AMIPRE is 4 to 5 minutes.
- After mixing, place the flakes into the mold.
- Press the flakes according to the desired density.
- The ideal time between mixing and pressing is 15 to 18 minutes.
Demolding
- Wait 40 to 60 minutes before demolding.
- Bonded foam lamination should be performed after 24 hours.
Check Out the Article on Cylindrical Block Viscoelastic Production [Click Here]
Standards for Bonded Foam
Bonded foams must comply with ABNT NBR 13579-1, adhering to the following requirements:
| Propriedades | D ≥ 30 |
| Resiliência, % (min) | 25 |
| D.P.C. a 50%, % (máx) | 25 |
| F.I.¹ a 40%, N (mín) | 250 |
| Perda de F.I. a 40%, (50% deflexão), % (máx) | 35 |
| Perda de espessura, % (máx) | 10 |
| ¹Força de identação a 40% sem pré-deflexão, conforme ABNT NBR 9176 |
Necessary Machinery
- A flake agglomerator
- Two adjustable crates (typically 1.6 x 2.00 x 70 cm in height, depending on the process and the piece being produced)
- Foam and fabric flocking machine
- Approximately 100 kg of flakes for one block
- Approximately 10% of Amipre 132/1 adhesive
Important to Remember…
- The more substrate mixtures used, the more adhesive will be required for proper adhesion.
Yield
- 1 block every 40 minutes.
See Also:
[Video] Success Factors in Bonded Foams.
Technology for Flexible Foams
Amino provides the most comprehensive range of solutions for Flexible Polyurethane Foams.
Our portfolio includes silicones, amines, pigments, additives, binders, and ready-to-use systems, ensuring consistency and quality when it comes to polyurethane. Additionally, our technical team consists of top polyurethane experts to assist and guide our clients toward the best solutions, combining high-quality raw materials with maximum efficiency in production processes.
Explore Amino’s Solutions for Flexible Foams
Performance Additives
- Surfactant Silicones
- Amine Catalysts for Expansion and Gelling
- Delayed Catalysts
- Low VOC Catalysts
- Tin Octoate
- Liquid and Paste Pigments
- Adhesion Promoter Additives (Flame Bonding)
- Cell Opener Additives
- Additives for Elongation and Tear Resistance
- Hardness Additives
- Anti-Scorching Additives
- Halogenated and Non-Halogenated Flame Retardants
Ready-to-Use Flexible Systems
- Viscoelastic for All-MDI Block Process
- Viscoelastic for TDI-Based Block Process
- Viscoelastic for MDI-Based Molded Process
- Hyper-Soft System for TDI-Based Block Process
- Hyper-Soft System for MDI-Based Molded Process
- HR Flexible System for MDI-Based Block Process
- HR Flexible System for TDI-Based Block Process
- HR Flexible System Molded, MDI- and TDI-Based
Complementary Products for Flexible Foams
- Bonded Foam Adhesive
- Adhesive for Foam-to-Fiber Bonding (Sponge)
- Gel Layers
Contact Us
To learn more about Amino Technology, call us at +55 11 4077-3777 or email us at vendas@amino.com.br.
