Kabond Foam, Heshan (2026)

16/07/2026

Open Cell vs. Closed Cell Foam

When talking about polyurethane foam, one of the most important concepts is open-cell and closed-cell structure.

In reality, it also determines:
✔ Air permeability
✔ Water resistance
✔ Compression behavior
✔ Thermal insulation
✔ Typical applications

Open-Cell Foam

In open-cell foam, many of the cell walls are broken, allowing neighboring cells to connect with each other.

This creates an interconnected structure where air can move freely through the foam.

Typical characteristics:
• Excellent breathability
• Good sound absorption
• Softer feel and higher comfort
• Easily absorbs water

Common applications:
• Mattresses
• Sofa cushions
• Acoustic foam
• Air filters

Closed-Cell Foam

In closed-cell foam, each cell remains sealed and isolated.
Since the cells are not connected, air and water cannot easily pass through the material.

Typical characteristics:
• Excellent water resistance
• Better thermal insulation
• Higher rigidity and dimensional stability
• Lower air permeability

Common applications:
• Thermal insulation panels
• Pipe insulation
• Automotive seals
• Marine flotation materials

Can Open-Cell Foam Be Manufactured Intentionally?

Yes.

In flexible PU foam production, manufacturers often use cell-opening additives, together with carefully balanced reaction conditions, to create the desired open-cell structure.

For some specialty foams, additional thermal or mechanical processing may also be used to further increase cell openness.
The final cell structure depends on the formulation, processing conditions, and product requirements.

Understanding the difference between open-cell and closed-cell foam helps engineers select the right material for the right application—not just based on hardness, but also on airflow, insulation, durability, and overall performance.

09/07/2026

Sticky Surface on PU Foam? Here Is How to Fix It

A sticky surface on polyurethane foam usually means one thing:
the reaction was not completed properly.

To solve this problem, we need to check the process step by step instead of only treating the surface.

1. Control the reaction temperature
Keep the raw material temperature stable, normally around 25–30°C.
For mold foam, the mold temperature should also be stable.
In cold seasons, preheat the raw materials before production to avoid slow reaction and incomplete curing.

2. Balance blowing and gelling reaction
If the foam rises too fast but the gel reaction is too slow, the foam structure may not form well, and the surface can remain sticky.
The catalyst system should be adjusted carefully.
Tin catalyst can help improve gelling speed, but the dosage must be controlled to avoid scorching, cracking, or overly fast reaction.

3. Check the isocyanate index
If the TDI/MDI index is too low, the reaction may be incomplete and the foam surface can become sticky.
If the index is too high, the foam may become hard, brittle, or even show burning inside.
Every time raw materials are changed, the formula should be checked again.

4. Control raw material quality
Raw materials are the foundation of stable foam quality.
Polyol activity, moisture content, TDI/MDI quality, and storage condition can all affect the final reaction.
Before production, especially when using a new batch of material, moisture and material condition should be checked.

5. Give the foam enough curing time
Foam does not finish reacting immediately after rising or demolding.
It still needs time for post-curing and gas release.
If the foam is processed too early, surface stickiness, deformation, or unstable size may appear later.

Emergency treatment for sticky foam:
For finished foam with slight surface stickiness, hot air treatment can sometimes help reduce the problem.
Some factories may also use talc powder for temporary surface handling.
But this is only a short-term solution and may affect bonding or further processing.

The correct way is still to solve the root cause from the formula, temperature, catalyst balance, material quality, and curing process.

In PU foam production, remember:
temperature controls the reaction, index controls the balance, and curing protects the final quality.

02/07/2026

Why Does PU Foam Surface Become Sticky?

In flexible PU foam production, sticky foam surface is a common problem.
The foam may feel wet, oily, or like uncured glue.

This problem does not only affect hand feel.
It can also create trouble during cutting, laminating, packing, and later processing.

In most cases, sticky surface means one thing:
the reaction has not fully finished, and some unreacted materials or low-molecular substances remain on the foam surface.

During PU foam production, two reactions happen together.

The blowing reaction creates gas and helps the foam rise.
The gelling reaction builds the foam structure and helps the foam cure and hold its shape.

If the gelling reaction is too slow, or the curing is not complete, the foam may look finished, but the surface may still remain sticky.

Common causes include:

1. Low temperature
Low material temperature, room temperature, or mold temperature can slow down the reaction.
Catalyst activity becomes weaker, and the foam may not cure well.

2. Catalyst imbalance
If gelling support is not enough, or if gas comes too fast, the foam surface may not form a stable structure in time.

3. Low isocyanate index
If there is not enough isocyanate, some polyol or other materials may not react completely.
This can leave a sticky or oily surface.

4. Unstable raw materials
Polyol activity, TDI condition, moisture content, and additive quality can all affect the final reaction result.

5. Not enough curing time
Foam demolding does not mean the reaction is finished.
If the foam is stacked, packed, or processed too early, heat and remaining substances may not release properly.
The surface may stay sticky for a longer time.

So, sticky foam surface should not be judged by one factor only.
You need to check temperature, catalyst balance, index, raw material condition, and curing time together.

Stable foam production is not only about making the foam rise.
It is about making the reaction finish properly, so the foam becomes stable, dry, and ready for processing.

26/06/2026

Slow-Recovery Foam Feels Hard and Recovers Too Slowly? Troubleshooting Guide

【Practical Tips for the Foaming Workshop】

When viscoelastic foam feels hard, resists compression, or recovers much more slowly than expected, the problem should not be blamed on one raw material immediately.

First, separate normal temperature sensitivity from a real production fault.

Viscoelastic foam may temporarily become firmer at low temperatures and recover after returning to room temperature. If it remains stiff, dry, and unusually slow at normal room temperature, check the process and raw materials.

Four common causes:

1.Unbalanced blowing and gelling reactions

If gelling develops too quickly, the foam structure may lock too early. If the front-end blowing reaction is too slow, the foam may become dense and firm.

2.Unstable chemical or workshop temperature

Low chemical temperature changes reaction speed and early cell formation. Stabilize the temperature before making major formulation changes.

3.Polyol selection or batch variation

Mixing standard flexible-foam polyol with viscoelastic polyol, changes in viscosity or activity, and unexpected moisture can all affect recovery and hand feel.

4.Insufficient curing

Viscoelastic foam needs enough time for post-reactions to continue. Cutting, compressing, or stacking it too early may lead to an incorrect performance assessment.

On-site adjustment:

Change only one variable at a time. Fine-tune the catalyst balance in small steps, stabilize chemical temperature, verify raw-material batches and moisture, and evaluate the foam only after sufficient curing.

Do not blindly add more water to soften the foam, and do not make large silicone changes. These actions may create coarse cells, closed cells, shrinkage, or collapse.

17/06/2026

The entire foaming process is essentially a rheological transition in which the system gradually changes from a purely liquid and viscous state into a three-dimensional crosslinked elastomer.

The viscoelastic balance between foaming and gelation directly determines the final foam structure and overall foam quality.

05/06/2026

Foam Scrap Loading Today

Foam scraps are packed and ready for shipment.

Step by step, container by container, we keep moving orders forward.

For foam recycling projects, stable supply and smooth loading are just as important as the machines.

Busy workshop, busy loading, busy shipment.

26/05/2026

Why Does Flexible PU Foam Cell Structure Vary So Much?

In the production of flexible polyurethane (PU) foam, cell structure has always been one of the core factors determining product quality. Whether it is comfort, rebound performance, breathability, or long-term stability in use, all of these characteristics are closely related to how the microscopic cells inside the foam are formed.

In many cases, such differences are simply attributed to formulation or equipment. However, if we trace the process back to an earlier stage, the true source of variation often appears at the very moment when foam cells are first “born,” namely the nucleation stage.

In most flexible PU foam systems, the primary source of gas is carbon dioxide generated by the reaction between water and isocyanate. As the reaction proceeds, increasing amounts of CO₂ are produced and dissolved in the polyol system. When the amount of dissolved gas exceeds what the system can stably accommodate under the given conditions, the system enters an unstable state.

In simple terms, there is “too much gas” trapped in the system, and it must be released in the form of bubbles. However, gas does not automatically or uniformly transform into stable foam cells, because the formation of a bubble itself must overcome an interfacial energy barrier.

During the initial nucleation stage, extremely small gas aggregates continuously appear in the system, but only a portion of them can survive and continue to grow. This is because the smaller the bubble, the stronger the effect of surface tension acting on it, making it more likely to be compressed and re-dissolved into the liquid phase.

Only when a bubble grows beyond a certain size can it escape this unfavorable condition and enter a stage of sustained growth. For flexible PU foam production, the key issue at this stage is therefore not simply whether bubbles appear, but how many of them are able to survive and participate in the subsequent formation of the cellular structure.

For this reason, industrial production rarely relies on random gas aggregation to achieve nucleation. Instead, nucleation is actively guided by processing conditions. During mixing, strong shear and turbulence inevitably entrain air and break it into a large number of microscopic bubbles. These microbubbles effectively act as pre-existing nucleation sites, making it much easier for gas to evolve and grow at these locations.

The greater the number of nucleation sites and the more uniform their distribution, the higher the density of initial bubbles, and the finer and more stable the resulting cell structure. From the perspective of the finished product, this usually translates into more uniform feel, more consistent rebound behavior, and a lower risk of coarse cells or bubble coalescence.

Of course, this guidance cannot be intensified without limit. Excessive shear, if not matched with timely structure formation, can also lead to cell instability. Nucleation must always be coordinated with the overall reaction kinetics of the system.

In this process, the role of surfactants cannot be overlooked. In flexible PU foam systems, foam stabilizers do far more than influence the visual appearance of cells.

They directly participate in stabilizing the nucleation stage. A suitable surfactant system can reduce the difficulty of forming gas–liquid interfaces, improve the survival rate of newly formed bubbles, and provide early-stage interfacial support, thereby reducing the likelihood of coalescence and collapse.

This is why, even when other conditions remain unchanged, adjusting the foam stabilizer system alone can lead to significant differences in cell structure.

As the reaction continues, the system temperature gradually rises due to the exothermic nature of polyurethane reactions. With increasing temperature, gas evolution and bubble growth are both accelerated. If the temperature rises too quickly in the early stage, bubbles may form faster than the system can establish sufficient structural strength, leading to non-uniform cell distribution.

If the reaction proceeds too slowly, nucleation may be insufficient, resulting in a low cell density. In practical production, the coordination between nucleation, bubble growth, and gelation is often far more important than any single parameter taken in isolation.

It should be emphasized that nucleation is not the only factor determining final cell structure, but it defines the quality of the starting point. In flexible PU foam, nucleation density affects cell fineness, nucleation stability influences structural uniformity, and nucleation controllability directly determines how wide the usable processing window will be.

Truly stable and reproducible foam quality is built upon a clear understanding and rational control of the nucleation process. This is the fundamental logic that allows flexible PU foam to progress from merely “foaming successfully” to achieving stable production and comfortable, reliable performance in use.

21/05/2026

How Do Manufacturing Processes Determine the Performance Limits of High-Resilience Foam?

Soft and cushiony to sit on yet able to rebound quickly, staying supportive after long periods without collapsing while remaining breathable—high-resilience foam has long become a core material in premium furniture, automotive seats, and medical supports.

As the “performance powerhouse” in the polyurethane family, its outstanding behavior is no accident: from raw-material ratios to molding and curing, every process step precisely regulates its molecular network and cell structure.

Today, let’s dig into the logic behind it and understand the strong correlation between process and performance!

Raw-Material Ratios:
Performance’s “Innate Genetics”—Tiny Differences, Huge Consequences

The core raw materials of high-resilience foam are polyether polyols and isocyanates (commonly a blend of TDI and polymeric MDI), along with additives such as crosslinkers, blowing agent (water), catalysts, silicone surfactants, and others. Different ratios directly determine the “ceiling” of the foam’s final performance.

Polyether polyols: Choosing the right reactivity is key. High-activity polyether must be used; a common choice is grafted polyether (often called “polymer polyol” or POP).

This type of polyol can form stiffer segments, providing strong support. If ordinary polyols or polyols with insufficient activity are used, the foam’s resilience and fatigue resistance will be greatly reduced.

Isocyanate index: The precision art of calculation. The dosage of isocyanate is by no means a simple proportion; it is precisely calculated through the isocyanate index. This index is the ratio of the actual dosage to the theoretical dosage required for complete reaction.

For high-resilience foam, this index is typically controlled between 105–115. If the index is too low, the reaction is incomplete and the foam becomes soft, weak, and easily deformed; if the index is too high, excessive crosslinking occurs, making the foam hard and brittle and even causing cracking.

Additive tuning: The “perfumers” who fine-tune the feel.

Crosslinkers (e.g., trimethylolpropane): A small addition (typically 0.5–3 parts per 100 parts of polyether) can significantly enhance the stability of the molecular network and improve load-bearing capacity and rebound. Too much, however, will make the foam overly hard.

Catalysts: A combination of amine catalysts and organotin catalysts is generally used to balance the “blowing reaction” and the “gelling reaction,” ensuring the foam rises smoothly and then solidifies quickly to form uniform, fine cells.

Silicone surfactants (surface-active agents): They are the “architects” of the cells, stabilizing cell walls and controlling cell size and open-cell rate, which are crucial to the final rebound speed and breathability.

Foaming And Molding:

The “Shaper” Of Cell Structure That Determines Rebound And Breathability

Foaming is the magical moment when foam transforms from liquid into a porous solid. Cold-mold molding is the mainstream process for modern high-resilience foam. It can react and mold near room temperature, consumes less energy, and enables more precise control of the cells.

Core control logic:

Temperature and mixing: Raw-material temperature must remain stable (typically 22–25°C), and the mold is kept at a constant temperature (about 45–50°C). Temperature fluctuations can seriously affect reaction speed and cell uniformity. The materials must be instantly mixed uniformly through high-speed mixing and injected into the mold within an extremely short time after mixing.

Cell-structure optimization: The performance soul of high-resilience foam lies in its high open-cell rate and uniform, fine cell structure. Ideally, cells are interconnected; when compressed, air can be expelled and re-enter quickly.

This is the physical basis for “instant rebound” and good breathability. Through precise control of silicone surfactants, this ideal structure can be created. Cells that are too large or uneven will disperse support and slow rebound.

Curing And Post-Treatment:

The “Stabilizer” Of Performance That Prevents Later Sagging

Foam just demolded only “looks” ready; internal chemical reactions have not fully ended, so curing is needed to “set” it.

Room-temperature curing: After demolding, the foam should be placed for 48–72 hours in a constant temperature and humidity environment to allow sufficient post-crosslinking of molecular chains and stabilize the cell structure. Foam with insufficient curing may meet initial performance targets, but is prone to permanent deformation after use.

Post-curing (thermal treatment): To further improve performance, the foam can be treated for several hours in an oven/tunnel at 60–80°C. This process can significantly improve mechanical strength, rebound, and fatigue resistance, keeping the foam in good condition after long-term use.

Crushing treatment (for specific needs): For applications with extremely high requirements, “crushing” is sometimes performed, meaning the foam is strongly compressed once.

This is intended to break any remaining extremely thin cell membranes, ensuring the open-cell structure is fully interconnected, thereby achieving the best breathability and rebound while further reducing long-term compression set.

Process Out-Of-Control Warnings:

These Problems Mean The Process Wasn’t Tuned Properly!

Slow rebound, soft sagging, weak support: Possibly due to insufficient polyol reactivity, a low isocyanate index, or inadequate curing.

Hard and brittle, with cracks: Usually caused by excessive crosslinker, an overly high isocyanate index, or uncontrolled post-curing temperature.

Uneven density, local dents: Problems often arise in the foaming stage: uneven mixing of materials, uneven mold temperature, or incorrect shot-weight calculation.

Shrinkage and deformation: An overly high closed-cell rate, insufficient curing, or a fundamental imbalance in the formulation.

16/05/2026

How to Identify High-Quality Flexible PU Foam?

When purchasing flexible PU foam, the most frustrating scenario for buyers is often: “The sample looks perfect, but the bulk order performs poorly.”

Even when density fully meets specifications, physical performance can still vary between batches. In a complex supply chain, relying solely on experience or hand feel is not enough. Buyers must establish an objective evaluation system based on production logic.

Below are the three core dimensions for identifying high-quality flexible PU foam:

I. Observing Internal Structure: Cell Morphology Determines the Foundation

The physical performance of foam is fundamentally determined by the microscopic structure of thousands of internal cells.

Cell uniformity:
After cutting, high-quality foam should show fine, evenly distributed cells. Visible large voids, bubbles, or hardened lumps indicate insufficient mechanical shear during foaming or unstable chemical reactions.

Cell openness and airflow:
Good flexible PU foam must have a high open-cell rate. Only when cells are interconnected can air be expelled instantly under compression. Excessive closed cells trap air inside, causing delayed rebound and even post-curing shrinkage or deformation.

Cell wall toughness:
Closely observe the cell “struts.” In high-quality foam, the cell walls are intact and elastic. This directly determines tear resistance and whether the foam will crumble or shed under repeated stretching.

II. Breaking Down Core Indicators: Using Data to Expose Quality Traps

Data is the only objective language. Focus on these four parameters that most strongly affect product lifespan:

Ball rebound resilience ≥45%:
This is a standard indicator of foam elasticity (typically for high-resilience grades). Foam meeting this value provides effective kinetic energy feedback. Low rebound leads to a soft, weak feel and faster elastic fatigue.

Compression set ≤30%:
This parameter directly defines service life. After being compressed for 22 hours at 70 °C, less permanent deformation indicates a more stable crosslinked network. This is the baseline for preventing irreversible sagging in sofas or mattresses.

Support feel (ILD):
High-quality foam delivers layered support—soft under light pressure and firm under deep compression. This tactile experience comes from precise indentation load control and defines overall comfort.

Tensile strength ≥0.8 MPa:
This is a rigid toughness indicator. Quality foam should resist tearing. Foam that can be easily torn by hand often indicates improper chain extender usage or insufficient curing time during production.

III. Tracing Process Origins: Ensuring Batch-to-Batch Stability

The core value of professional flexible PU foam supply lies in stability. Evaluate factory control capability through the following:

Density consistency verification:
Randomly sample different positions from bulk foam blocks and weigh them. High-level factories control foaming temperature variation within ±1 °C and maintain stable pressure, ensuring minimal density deviation from the first block to the hundredth. Large density fluctuations indicate insufficient equipment precision.

Odor and safety assessment:
Freshly unpacked foam with pungent or irritating odors often contains excessive free monomers (such as TDI). This reflects incomplete reaction conversion, affecting physical properties and posing long-term environmental and health risks.

Aging resistance:
Quality formulations include appropriate antioxidants to slow yellowing and powdering. While yellowing is inevitable, high-quality foam maintains physical performance stability longer across diverse climate conditions.

Veteran Technicians’ Practical Inspection Methods

When no instruments are available on-site, use these quick screening techniques:

Press and release forcefully:
Upon releasing your hand, the foam should rebound instantly like a spring. Delayed recovery signals poor quality.

Tear resistance test:
Pull firmly at the foam edge. Only foam with strong toughness and elongation qualifies.

Smell test:
No sharp chemical odor or off-smell is the minimum acceptance threshold.

Light transmission check:
Hold a thin foam piece against bright light. Uniform light pe*******on without dark clumps indicates extremely stable foaming.

11/05/2026

What Will Define the PU Foam and Mattress Supply Chain in 2026?

Introduction: From Industry Consolidation to the Era of Efficiency

Entering 2026, the global polyurethane industry has moved into a phase of deep structural reconfiguration. As milestone mergers and acquisitions—such as ADNOC’s integration with Covestro—enter the ex*****on stage, and Wanhua Chemical further consolidates its global capacity, the industry is shifting from pure scale expansion toward a new cycle driven by technological innovation and multi-dimensional compliance.

For global mattress manufacturers, the core challenge in 2026 lies in building a highly resilient supply system amid a volatile macroeconomic environment.

I. Supply Side: Post-Consolidation Dividends and Risk Hedging

The large-scale industry consolidation of 2025 begins to release operational synergies in 2026. Global raw material distribution systems are becoming more efficient, and supply volatility of high-performance isocyanates (MDI/TDI) has eased to some extent.

However, despite increasing supply-side concentration, raw material prices remain dynamic due to a higher share of green electricity, fluctuations in natural gas prices, and the internalization of carbon emission costs. Against a backdrop of geopolitical uncertainty and volatile global shipping costs, partners with globally distributed chemical production bases and strong supply-chain resilience now offer value that goes far beyond simple low-price strategies.

II. Green Barriers: From Voluntary Sustainability to Mandatory Market Access

By 2026, sustainability has shifted from a brand value enhancer to a hard entry threshold for international markets. Regulatory frameworks in Europe and North America covering carbon footprint accounting and recycled material ratios are now fully implemented.

CO₂-based polyols and bio-based raw materials produced via the mass balance approach have made significant progress within mainstream mattress supply chains. Beyond CertiPUR-US and GRS certifications, ISCC PLUS certification has emerged as a core indicator for evaluating suppliers’ expertise in circular economy and bio-based material applications.

III. Manufacturing: Breakthroughs in High-Efficiency Processes and Thermal Management

Advancements in production technology are redefining the functional boundaries of foam, enabling finished products to achieve stronger differentiation in downstream markets. Optimization of new-generation amine catalysts and the adoption of low-energy foaming systems have effectively reduced volatile organic compound emissions and overall energy intensity during production.

Meanwhile, the introduction of graphene and high-performance aerogel additives is significantly enhancing mattress thermal management capabilities and long-term antibacterial performance. Through deep integration with flexible PU foam substrates, mattress components are evolving from single-function support materials into multifunctional performance modules.

IV. Risk Management: Compliance and Digital Traceability Systems

As trade compliance requirements grow increasingly complex in 2026, supply-chain transparency has become a matter of survival. National energy-efficiency and emission standards for polyurethane products are accelerating the phase-out of outdated capacity.

The adoption of safer railway transport modes and the establishment of digital traceability systems not only reduce hazardous chemical logistics risks but also provide complete carbon footprint tracking for end products, meeting the regulatory expectations of global buyers.

Conclusion: A Return to the Fundamentals of Business Strategy

The polyurethane market in 2026 stands at a critical transition point—from scale-driven growth to quality-driven development. As green standards become mandatory thresholds and supply-chain stability replaces price volatility as the core competitive variable, the underlying logic of industry competition has fundamentally changed.

In this cycle, companies that maintain strategic focus, invest deeply in sustainable technologies, and embrace digital transparency will secure a decisive global competitive advantage over the next five years.

Kabond Foam

16/07/2026

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