AC (azodicarbonamide) and OBSH (4,4′-oxybis(benzenesulfonyl hydrazide)) are chemical blowing agents used to create cellular structures in plastics, rubber, and other polymer products. AC generally offers higher gas yield and lower material cost, making it attractive for cost-sensitive, high-volume production. OBSH typically decomposes at lower temperatures and can be suitable for applications that require controlled foaming or finer cell structures. The right choice depends on the polymer, processing temperature, required foam density, cell structure, emissions requirements, and total production cost. Buyers can compare the available options through Shitong's blowing agent product range before selecting a grade for their formulation.
The main difference is how each agent decomposes during processing and how its gas generation fits the polymer's processing window. Their performance is also affected by particle size, additive compatibility, activation temperature, pressure, and the formulation as a whole.
| Comparison factor | AC blowing agent | OBSH blowing agent |
|---|---|---|
| Chemical name | Azodicarbonamide | 4,4′-Oxybis(benzenesulfonyl hydrazide) |
| Typical appearance | Usually pale yellow powder | Usually white powder |
| Decomposition temperature | Commonly reported around 160–220°C, depending on grade and test conditions | Commonly reported around 130–180°C, depending on grade and test conditions |
| Gas yield | Generally higher; often reported around 200–300 mL/g for certain grades | Generally lower; often reported around 120–160 mL/g for certain grades |
| Processing profile | Often suited to processes that can accommodate higher activation temperatures | Often useful when a lower-temperature decomposition profile is needed |
| Foam structure | Can produce a range of cell structures depending on formulation and processing | Can support fine and uniform cells in suitable formulations |
| Cost | Often more economical for high-volume applications | Often carries a higher material cost |
| Common application considerations | High expansion, throughput, and cost control | Temperature-sensitive processing and controlled cell structure |
The numerical ranges above are indicative rather than universal specifications. Gas yield depends on the measurement method and test conditions, while decomposition temperature can vary with grade, heating rate, and additives. Request the technical data sheet for the specific product before using these values in process design.
AC, or azodicarbonamide, decomposes when heated and releases gases that expand the polymer matrix. The decomposition profile and gas-generation rate must be compatible with the material's melting, plasticization, and curing behavior.
High gas yield
Many AC grades provide relatively high gas yield per unit mass. This can make them attractive when a formulation requires substantial expansion or when the cost of blowing agent is an important production consideration.
Cost-effective large-scale production
AC is widely used in foamed plastics and rubber products. Its relatively economical pricing can benefit manufacturers producing large volumes, provided the selected grade meets the product's quality and processing requirements.
Broad application potential
Depending on the formulation and activation profile, AC can be used in applications such as polymer sheets, profiles, footwear materials, and rubber products. Suitability must be established for the specific resin or elastomer and the intended process.
AC commonly requires a higher processing temperature than OBSH, although the exact activation range depends on the grade and formulation. If decomposition begins too early or too late relative to polymer flow and solidification, the finished product may develop uneven cells, excessive expansion, or other defects.
AC decomposition can also generate a mixture of gases and decomposition residues. Manufacturers should evaluate the relevant safety documentation, ventilation requirements, emissions, and compatibility with the finished product rather than assuming that high gas yield alone guarantees better performance.
OBSH is a chemical blowing agent commonly selected for applications that benefit from a lower-temperature decomposition profile. During processing, it releases gas that forms cells within the polymer or rubber matrix.
Its performance depends on the specific grade and how its decomposition behavior aligns with the material's processing window.
Lower-temperature processing potential
OBSH can be appropriate when the polymer or production process cannot readily accommodate the activation temperatures associated with some AC grades. This may help manufacturers coordinate gas generation with polymer flow and structure stabilization.
However, a lower decomposition temperature does not automatically mean lower total energy consumption. Barrel temperatures, residence time, equipment efficiency, and curing requirements also affect energy use.
Potential for fine, uniform cells
In a compatible formulation with stable processing conditions, OBSH can help produce a fine and uniform cellular structure. The actual cell size depends on the polymer, nucleating agents, dispersion, pressure, gas-generation rate, and cooling or curing process.
Cell sizes such as 50–100 μm may be reported for particular formulations, but this should not be treated as a guaranteed result for every OBSH grade or application.
Useful for selected rubber and polymer applications
OBSH may be considered for rubber foams, footwear components, seals, synthetic leather, and certain PVC or other polymer foam products. The formulation must be tested to confirm cell uniformity, density, surface quality, and the required mechanical properties.
OBSH often has a higher purchase price than AC and may provide a lower gas yield per unit mass. Whether it is economically preferable depends on the dosage needed, scrap rate, product specifications, cycle time, and processing efficiency.
Manufacturers should also review the product's decomposition profile and safety data. Lower odor or a particular gas composition should not be assumed to mean that a formulation is emission-free or safe without appropriate controls.
For product-specific details, see Shitong's OBSH blowing agent information.
Neither AC nor OBSH is universally better. Select the agent that matches the polymer's processing window and the performance requirements of the finished foam.
AC may be a suitable starting point when:
The production line operates within the selected grade's effective decomposition range.
High gas yield is an important formulation requirement.
Material cost is a major purchasing consideration.
The target product can accommodate the resulting cell structure and decomposition characteristics.
Production trials demonstrate acceptable expansion, density, and mechanical performance.
For high-volume production, compare the cost per finished unit rather than the price per kilogram alone. A low-cost blowing agent can become less economical if it causes inconsistent foam quality or excessive scrap.
OBSH may be worth evaluating when:
The polymer or process requires a lower-temperature decomposition profile.
Controlled expansion and fine cell structure are important.
The selected formulation benefits from the agent's gas-generation behavior.
Product quality requirements justify a potentially higher material cost.
Trials confirm that the agent is compatible with the resin, additives, equipment, and production cycle.
For sensitive applications, ask the supplier to confirm the recommended processing conditions and provide relevant technical documentation.
Even the appropriate blowing agent can produce poor results when the formulation or processing conditions are unstable.
| Observed problem | Possible cause | Recommended checks |
|---|---|---|
| Oversized or merged cells | Excessive gas generation, insufficient melt strength, or poor dispersion | Review dosage, processing temperature, and polymer melt behavior |
| Uneven cell distribution | Inconsistent mixing, unstable pressure, or uneven temperature | Check additive dispersion, feeding, and temperature uniformity |
| Insufficient expansion | Inadequate decomposition, unsuitable dosage, or excessive melt resistance | Verify the grade's decomposition profile and the process window |
| Pinholes or irregular voids | Material contamination, moisture where relevant, or unstable gas release | Inspect raw materials, handling, and processing records |
| Surface defects | Poor compatibility, excessive expansion, or unsuitable cooling and curing | Review the complete formulation and production sequence |
| Inconsistent density between batches | Raw-material variation or unstable operating conditions | Compare batch records, dosage accuracy, and machine settings |
These symptoms can have several causes. Avoid changing the blowing-agent dosage, processing temperature, and lubricant content simultaneously. Controlled trials make it easier to identify the factor responsible for a defect.
The lowest price per kilogram does not necessarily produce the lowest manufacturing cost. Buyers should compare the cost and performance of each agent within the same finished-product specification.
Evaluate the following factors:
Dosage requirement: Determine the amount needed to achieve the target density and expansion.
Gas yield: Compare values measured using compatible methods and conditions.
Processing temperature: Assess whether the production line can operate efficiently within the grade's decomposition range.
Cell structure and quality: Measure cell distribution, density uniformity, surface quality, and mechanical properties.
Production efficiency: Consider cycle time, output stability, and energy consumption.
Scrap and rework: Include material waste and quality losses in the calculation.
Safety and compliance: Review handling, ventilation, emissions, and applicable regulatory requirements.
Supply consistency: Confirm that the supplier can provide consistent grades and the necessary technical documentation.
A practical comparison should use trial data from the intended production line whenever possible.
Before placing an order, provide the supplier with the polymer type, processing method, target foam density, required cell structure, and operating temperature range. Ask for the following information for each candidate grade:
Recommended decomposition or activation temperature and test method.
Gas yield and measurement conditions.
Particle size and relevant physical specifications.
Recommended dosage range for the intended polymer, where available.
Compatibility with other formulation ingredients.
Relevant decomposition, handling, storage, and safety information.
Batch quality documentation and sample availability.
Processing recommendations for the intended application.
For demanding applications, validate the material using a controlled trial and agreed acceptance criteria. Supplier recommendations should be treated as a starting point, not a substitute for testing on the actual production line.
AC generally offers a higher gas yield per unit mass in many commonly cited grade comparisons. However, the final expansion depends on decomposition behavior, formulation, pressure, and processing conditions, so gas yield alone does not determine overall performance.
OBSH is commonly selected for applications requiring a lower decomposition temperature than many AC grades. The actual processing window must be confirmed using the technical data sheet for the specific grade and the polymer formulation.
OBSH can produce fine and uniform cells in suitable formulations, but neither agent guarantees a particular cell size. Mixing quality, melt strength, nucleation, gas-generation rate, and cooling or curing conditions all affect the result.
OBSH is often more expensive on a per-kilogram basis, but the actual price varies by grade, supplier, and order volume. Compare the dosage required, product quality, production efficiency, and scrap rate to assess the total cost.
The feasibility of combining blowing agents depends on their decomposition profiles, the polymer, and the required foaming behavior. Do not combine them without checking compatibility and conducting controlled formulation trials.
Selecting between AC and OBSH requires balancing gas yield, decomposition temperature, cell structure, processing stability, and total production cost. The most reliable choice is the grade that performs consistently within the intended formulation and manufacturing conditions.
For technical information, product recommendations, or sample inquiries, contact Shitong at cindy@stgaocai.com or visit www.shitonggaocai.com.
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