Rebonded Foam Machine: Key Features & Production Benefits

PU foam scrap is a common issue for foam factories. Cutting and converting large blocks of flexible PU foam generates PU foam scrap in different sizes. If these materials are stored for long periods or discarded, they occupy production space and waste materials that may still be reused.

A rebonded foam machine converts these scraps into rebonded foam blocks for mattresses, furniture, carpet underlay, protective packaging, and other products. For foam producers, mattress manufacturers, and foam converters, this equipment can improve scrap utilization and expand the factory’s product range.

What Is a Rebonded Foam Machine?

A rebonded foam machine is used to recycle flexible PU foam scrap. It shreds existing PU foam waste, mixes it with a binder, and compresses and cures the mixture inside a mold box to form rebonded foam blocks with the required density and shape.

The production process includes PU foam shredding, weighing, binder addition and mixing, compression molding, and downstream cutting. Steam-assisted curing is available as an option.

The PU foam scrap is first processed into small, relatively uniform particles by a shredder. It is then weighed and transferred into the mixing tank. Operators add the required amount of binder according to the PU foam scrap weight and production formula, allowing the particles and binder to mix thoroughly.

The mixed material is unloaded into a square or cylindrical mold box and compressed by a hydraulic pressing plate. Non-steam machines use natural curing, while steam-equipped machines use steam to assist binder curing and shorten curing and demolding time.

Key Features of High-Quality Rebonded Foam Machinery

1. Uniform Mixing System

The mixing tank should provide sufficient space for the PU foam particles and binder to blend properly. An appropriate mixing structure, forward and reverse rotation, and high- and low-speed control help improve mixing uniformity and reduce local binder shortages or uneven distribution.

2. Stable Hydraulic Pressing System

The hydraulic pressing system compacts the PU foam scrap mixture and controls the block height, density, and shape. Stable and evenly distributed pressure helps maintain greater density consistency across different areas of the same rebonded foam block while improving forming stability between batches.

3. PU Foam Scrap Weighing System

The weighing system measures the PU foam scrap used in each batch, helping operators add the appropriate amount of binder according to the production formula. Weighing accuracy directly affects binder control and batch consistency.

4. Optional Steam-Assisted Curing System

Steam-equipped machines use steam to assist binder curing, shortening curing and demolding time and improving mold box turnover efficiency.

5. Square and Cylindrical Mold Box Configurations

Both square and cylindrical mold boxes can use steam-assisted or natural curing. Square mold boxes are suitable for conventional rebonded foam blocks, while cylindrical mold boxes are commonly used for blocks that will later be skived into rolls, such as carpet underlay. Mold box type and size should be selected according to the finished product, daily output, and downstream cutting process.

Production Benefits for Foam Factories

1. Improved PU Foam Scrap Utilization

Rebonded foam production allows factories to return suitable PU foam scrap to production, reducing material storage and disposal pressure. Not all PU foam waste is suitable for direct recycling. The usable proportion depends on the PU foam type, cleanliness, and target product requirements.

2. Lower Material Costs for Rebonded Foam

Rebonded foam is produced mainly from PU foam scrap and binder. It does not require the complete chemical system used to produce virgin foam. For factories with a stable supply of PU foam scrap, this can reduce material costs for rebonded foam products.

3. A Wider Range of Products

Rebonded foam in different densities and sizes can be used for mattress support layers, furniture filling, carpet underlay, cushioning pads, and other products with different support and cost requirements.

Configuration Comparison: With or Without Steam

When selecting a foam rebonding machine, factories should determine whether steam-assisted curing is required based on daily output and finished product quality requirements.

Common Applications of Rebonded Foam

1. Mattresses and Furniture

Rebonded foam can be used for mattress support layers, sofa padding, office chair cushions, and other parts requiring specific support and density. The appropriate density and hardness should be selected according to the product structure.

2. Carpet and Flooring Underlay

Rebonded foam can be processed into carpet underlay and selected flooring cushioning materials to provide cushioning, support, and impact-noise reduction. Rebonded foam blocks produced in cylindrical mold boxes can be skived into rolls for these applications.

3. Fitness Mats and Cushioning Pads

Depending on density, thickness, and surface treatment, rebonded foam can be used for selected fitness mats, sports cushioning pads, and floor protection mats.

4. Protective Packaging

Rebonded foam can be processed into packaging liners and cushioning pads for hardware, handicrafts, and other products. Suitability depends on the product weight, transportation method, and cushioning requirements.

5. Sound-Absorbing Materials and Vehicle Carpet Underlay

Rebonded foam that meets the required density, thickness, and acoustic performance may be used in selected sound-absorbing products or vehicle carpet underlay. These applications require performance testing, and standard rebonded foam should not be treated as a universal soundproofing or industrial vibration-isolation material.

6. Other Supporting Materials

Rebonded foam can also be used for shoe insoles, luggage and bag padding, and other products with specific cost, support, and elasticity requirements.

How to Choose the Right Rebonded Foam Machine

Daily output and finished product quality are the two most important factors when selecting a rebonded foam machine.

If the factory has lower output requirements or places greater importance on rebonded foam quality, a non-steam machine may be more suitable. Natural curing takes longer, so the number of mold boxes should be selected according to the required daily output.

If the factory requires higher output, shorter curing and demolding time, and faster mold box turnover, a steam-equipped machine is more suitable.

A single-mold steam rebonded foam machine is suitable for moderate output requirements and factories that do not need intensive continuous mold box cycling.

A dual-mold steam rebonded foam machine is suitable for higher output and continuous batch production. When one mold box cannot meet the production schedule, a dual-mold configuration can improve overall production efficiency.

If the factory already has a steam boiler, it can purchase the steam-equipped rebonding unit without adding another boiler.

Factories should also select a square or cylindrical mold box according to the target product. Mold box size and quantity should be determined by block dimensions, daily output, factory space, and the downstream cutting process.

FAQs

What PU Foam Scrap Size Is Suitable for a Rebonded Foam Machine?

PU foam scrap should be shredded into small, relatively uniform particles. Oversized pieces may cause uneven filling or insufficient bonding, while excessively fine particles may increase binder consumption. The final particle size should be adjusted according to the PU foam type, target density, and machine configuration.

Can PU Foam Scraps of Different Colors and Densities Be Mixed?

PU foam scraps of different colors and densities can usually be mixed, provided that the resulting material meets the density, hardness, color, and performance requirements of the target rebonded foam product.

How Long Does a Rebonded Foam Block Need to Cure?

With steam-assisted curing, a rebonded foam block can usually be demolded after approximately 15–20 minutes, depending on the block size, binder condition, and production process. After demolding, it generally needs about one day of drying before cutting.

Rebonded foam produced without steam requires a longer natural curing period. The actual time depends on the binder, block size, and production conditions.

Choose a Sabtech Rebonded Foam Production Solution

Sabtech can configure shredding, weighing, mixing, compression molding, optional steam curing, and downstream cutting equipment according to the customer’s PU foam scrap source, target product, daily output, finished product quality requirements, and factory space.

For a new rebonded foam production line or an upgrade to an existing process, equipment selection should consider mold box quantity, curing method, production turnover, and downstream cutting requirements in addition to the machine price.

To determine whether your project requires a square or cylindrical mold box, steam or non-steam curing, or a single- or dual-mold configuration, contact Sabtech for an equipment proposal and quotation based on your production requirements.