I define OBSH blowing agent as a chemical blowing agent based on 4,4'-oxybis(benzenesulfonyl hydrazide). It decomposes when heated and releases gas within a polymer or rubber compound, creating a cellular structure such as foam, sponge, or microcellular material. For B2B buyers, OBSH is mainly evaluated by its decomposition temperature, gas-release behavior, particle size, compatibility with the formulation, and the consistency of the supplied grade.
OBSH is used in selected thermoplastics, elastomers, synthetic rubber, PVC-related formulations, and other materials that require controlled foaming. Its suitability depends on the processing temperature and the final product requirements rather than on the chemical name alone. In this guide, I explain its properties, functions, application scenarios, material options, purchasing specifications, and the supplier information I recommend checking before placing an order.
OBSH is an organic chemical blowing agent that releases gas during thermal decomposition. The released gas expands the surrounding polymer or rubber compound when the material has sufficient melt strength or compound viscosity to retain the cells. The result can be a lightweight, resilient, or insulating structure, depending on the base material and processing design.
The abbreviation OBSH refers to 4,4'-oxybis(benzenesulfonyl hydrazide). Its molecular formula is commonly stated as C12H14N4O5S2. In commercial use, I do not treat the molecular formula as a complete product specification, because commercial grades can differ in purity, particle size, moisture, surface treatment, and decomposition behavior.
When the compound reaches the activation temperature, OBSH decomposes and forms gas. This gas must be generated at a suitable stage of processing so that it can expand the material without escaping prematurely. The compound therefore needs an appropriate balance between gas generation, melt strength, curing behavior, mold filling, and cooling.
In practical production, OBSH is usually added as part of a formulated system rather than used as an isolated ingredient. Compounders may evaluate activators, stabilizers, pigments, fillers, plasticizers, lubricants, and other additives at the same time. I recommend confirming the complete formulation because an additive that improves dispersion or processing can also influence nucleation, cell size, surface quality, and final density.
OBSH is generally selected for systems that process in a temperature range compatible with its thermal decomposition. A commonly referenced decomposition range is approximately 155–165°C, but this should be treated as a typical technical reference rather than a guaranteed value for every grade. Buyers should request the supplier’s test method and compare the onset temperature, peak decomposition temperature, and processing window.
The amount and timing of gas release influence expansion ratio, density, and cell structure. Commercial technical data may report gas evolution in milliliters per gram, with some OBSH grades commonly specified near 125–135 ml/g under defined laboratory conditions. Because test temperature, heating rate, sample preparation, and measurement method affect the result, I recommend using gas yield only for like-for-like grade comparison.
Particle size influences how evenly OBSH disperses through a rubber or polymer compound. Finer, well-controlled particles may support more uniform distribution, while poor dispersion can contribute to local over-foaming, coarse cells, surface defects, or inconsistent density. A buyer should review the stated particle-size specification, sieve residue, moisture level, and recommended incorporation method before approving a grade.
OBSH must be evaluated against the entire formulation. The base polymer, filler loading, plasticizer level, curing system, shear history, and mold temperature can all affect the final foam. I avoid describing OBSH as universally compatible; instead, I recommend a small-scale trial using the intended compound and production equipment.
OBSH can be considered for sponge rubber, profiles, seals, gaskets, mats, grips, and other elastomeric products where reduced density or a cellular structure is required. The final result depends on whether the rubber compound can retain the generated gas during vulcanization or thermal processing. For these applications, buyers should assess compression set, resilience, surface appearance, dimensional stability, and odor requirements together with expansion.
Selected PVC and thermoplastic systems may use OBSH when the processing temperature and decomposition profile are suitable. Typical evaluation areas include sheet, profile, coating, insulation, footwear components, and molded parts, although the exact application depends on the formulation and equipment. I recommend checking whether OBSH activates within the material’s processing window without causing premature gas loss or an unstable foam structure.
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Foaming can reduce material consumption and lower the density of certain products. It may also contribute to cushioning or thermal insulation, but these outcomes are not automatic and must be verified in the finished part. Density, closed-cell content, thermal conductivity, water absorption, mechanical strength, and dimensional recovery are useful test targets for application development.
OBSH is not normally selected only by the word “OBSH.” Suppliers may offer different grades based on purity, particle-size distribution, surface treatment, activation behavior, packaging format, or suitability for a specific polymer system. Some products may be supplied as powder, while others may be incorporated into a masterbatch or pre-dispersed carrier to simplify handling.
| Buyer requirement | Specification to review | Why it matters |
|---|---|---|
| Controlled foaming | Decomposition profile and gas evolution | Helps match gas release with the processing cycle |
| Uniform cell structure | Particle size, dispersion, and moisture | Supports consistent distribution through the compound |
| Stable production | Batch consistency and packaging protection | Reduces variation during storage and dosing |
| Regulated-market supply | SDS, technical data, and applicable compliance documents | Helps support internal approval and import procedures |
First, I compare the compound’s actual temperature profile with the supplier’s OBSH decomposition data. I also review residence time, heating rate, pressure, screw configuration, mold temperature, and curing conditions. A nominal temperature match is not enough if the material reaches the activation range too early or too late.
Next, I identify the target density, expansion level, cell size, hardness, flexibility, compression behavior, and surface quality. A packaging foam, rubber seal, footwear component, and extruded profile may require very different cell structures. This step prevents the buyer from choosing a grade based only on gas yield or price per kilogram.
I then review fillers, pigments, plasticizers, curing agents, lubricants, and possible activators. These ingredients can change viscosity, heat transfer, decomposition behavior, and cell nucleation. Laboratory screening should compare dosage levels and processing conditions while keeping the other variables controlled.
A laboratory beaker or small mixer cannot fully reproduce an extrusion line, injection machine, compression mold, or continuous vulcanization process. After initial screening, I recommend a pilot trial using representative equipment and realistic residence time. The evaluation should record density, dimensions, visual defects, mechanical properties, odor, and batch-to-batch repeatability.
Before purchasing, I suggest requesting the current technical data sheet, safety data sheet, specification limits, packaging details, storage recommendations, and lot identification method. I also ask whether the quoted values are typical values or guaranteed limits. This distinction is important because a typical value should not be treated as a contractual specification without written confirmation.
Buyers should also clarify minimum order quantity, sample availability, production lead time, export packaging, shelf-life guidance, and the process for handling quality claims. If the application is sensitive to dispersion, a pre-dispersed option or controlled particle-size grade may be worth comparing with standard powder. Supplier communication should focus on the actual polymer, equipment, dosage range, and target performance rather than a generic product description.
At Shitong, I approach OBSH supply as a formulation and sourcing requirement, not simply as a commodity transaction. We can discuss the intended rubber or plastic system, processing temperature, dosage objective, packaging preference, and documentation needed for internal evaluation. Where the formulation is not yet finalized, I recommend beginning with a representative sample and a controlled trial rather than making an unsupported performance promise.
Our role as a manufacturer, supplier, and exporter is to help buyers compare the appropriate grade, confirm available specifications, and organize practical supply details. We can also review questions about particle size, storage, batch identification, and application fit based on the information provided by the buyer. Final suitability should always be confirmed through the buyer’s own technical testing and production validation.
OBSH blowing agent is a heat-activated material used to generate gas and form cellular structures in suitable rubber and plastic compounds. Its main selection factors are decomposition behavior, gas evolution, particle size, dispersion, compatibility, and consistency under the intended processing conditions. It can be a practical option when the formulation and equipment provide enough control to retain and stabilize the generated cells.
My recommended next step is to prepare the base polymer, processing temperature, target density, product type, estimated dosage, and required documents before contacting a supplier. Ask for the technical data sheet and sample, run a controlled screening test, and then confirm performance on production-relevant equipment. Contact Shitong with these details so we can discuss an OBSH blowing agent grade and supply plan aligned with your B2B project.
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