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Benzenesulfonyl Hydrazide (BSH, CAS 80-17-1): A Practical Guide to This Low-Temperature Chemical Blowing Agent
Benzenesulfonyl hydrazide, usually shortened to BSH, is a white crystalline powder used mainly to create foam structures in rubber and plastics. When heated, it decomposes and releases nitrogen gas, which forms the cells in the finished product. This guide explains how BSH works, what the specification numbers mean in practice, how to avoid common processing problems, and how to handle it safely.
What Is Benzenesulfonyl Hydrazide?
BSH has the molecular formula C6H8N2O2S (linear formula C6H5SO2NHNH2) and the CAS number 80-17-1. It appears in trade literature under several names, including Porofor BSH, Celogen BSH and Genitron BSH. Industrially, it is made by reacting benzenesulfonyl chloride with hydrazine. That is one reason it sits close to the sulfonyl chemistry Jinli produces, such as benzenesulfonyl chloride.
The compound is a solid that does not dissolve in water. That has a practical benefit: BSH disperses as fine particles in rubber compounds and plastic melts rather than migrating with moisture.
Specifications from the Manufacturer
The table below reproduces the check-points that Jinli Chemical publishes for its BSH grade, with a plain-language note on why each one matters.
| Check-point | Unit | Specification | Why it matters |
|---|---|---|---|
| Appearance | - | White powder | Yellowing can signal age, heat exposure or contamination. |
| Water | % max | 0.5 | Excess moisture causes clumping and uneven dispersion. |
| Decomposition temperature (5 °C/min, in air) | °C min | 143–147 | Sets the processing window; see the note below. |
| Gas volume in air | ml/g | 120–130 | Determines how much foam each gram can produce. |
| Ash | % | 0.1 | Low ash means fewer inorganic residues in the finished foam. |
| pH | - | 3.0–7.0 | Acidic residues can interact with cure systems and other additives. |
A note on decomposition temperature. The 143–147 °C figure above is a specification measured under fixed test conditions (5 °C/min heating in air). Other published sources describe the onset of gas release closer to 105 °C, and the number you actually see depends on heating rate, particle size, and whether activators are present in the compound. Treat the specification as a quality-control value, and run a small trial in your own formulation to find the real foaming window.
Key Physical and Chemical Properties
| Property | Value / Description |
|---|---|
| Molecular formula | C6H8N2O2S |
| CAS number | 80-17-1 |
| Appearance | White to light-colored crystalline powder |
| Water solubility | Insoluble |
| Organic solvents | Soluble in common organic solvents such as acetone |
| Gas released on decomposition | Mainly nitrogen |
| Hazard class (supplier SDS) | Flammable solid; heating may cause fire |
How BSH Works as a Blowing Agent
A chemical blowing agent is added to a polymer compound in small amounts. Once the compound reaches the agent's decomposition range, the agent breaks down and releases gas. The gas dissolves in the softened polymer, forms tiny bubbles, and those bubbles grow into cells as the material sets. BSH releases mostly nitrogen, an inert gas, which is why it is widely used in rubber foams and cellular plastics.
Because BSH decomposes at a lower temperature than many other sulfonyl hydrazide agents, it suits materials that cure or soften at moderate temperatures. One published study of natural rubber insulation reported that a loading of 6 phr gave a maximum expansion ratio of 324% and a thermal conductivity as low as 0.040 W/m·K (see reference 1). That result comes from a specific formulation, so use it as a starting point for trials, not as a guaranteed outcome.
Typical Applications
The main uses of BSH are:
- Foam rubber: natural and synthetic rubber sponge, seals, insulation sheets and soles.
- Foamed plastics: low-temperature processing of selected thermoplastics and plastisols.
- Chemical synthesis: BSH also serves as an intermediate in organic synthesis, for example in producing sulfonyl azides and other sulfonyl derivatives.
Note that BSH is not a plasticizer, even though some product listings group it with plasticizers. If you need a plasticizer, Jinli's separate N-butyl benzene sulfonamide range is the appropriate category.
Choosing Between BSH and Related Blowing Agents
Jinli Chemical lists several related agents in the same product family. The best choice depends mostly on the processing temperature of your material.
| Product | General positioning | Learn more |
|---|---|---|
| Benzenesulfonyl hydrazide (BSH) | Low-temperature foaming of rubber and plastics | BSH page |
| P-toluenesulfonhydrazide (TSH) | Closely related sulfonyl hydrazide with a methyl group on the ring | TSH page |
| 4,4'-Oxybis(benzenesulfonyl hydrazide) | Bis-hydrazide, commonly used where a higher decomposition range is needed | OBSH page |
| P-toluenesulfonyl semicarbazide (RA/TSSC) | Semicarbazide type for higher-temperature systems | RA/TSSC page |
Exact decomposition ranges differ by grade and test method, so request the current technical data sheet for each product before you compare them side by side. Browse the full range on the Forming agent & Blowing agent page.
Practical Processing Tips and Troubleshooting
| Symptom | Likely cause | What to try |
|---|---|---|
| Premature foaming during mixing | Mixing temperature too close to the decomposition range | Lower the batch temperature, shorten mixing time, add BSH late in the cycle. |
| Low expansion | Cure or set happens before gas is released, or loading is too low | Adjust cure timing, increase loading in small steps, check material age. |
| Coarse or uneven cells | Poor dispersion or clumped powder | Keep the powder dry, pre-blend with a carrier, and confirm moisture is within specification. |
| Residue odor or surface staining | Decomposition by-products remaining in the part | Allow adequate post-cure ventilation and test the end use, especially for skin-contact goods. |
A sensible trial routine is to change one variable at a time (loading, then temperature, then cure time) and record foam density each run. That gives you a repeatable recipe rather than a lucky one.
Safe Handling and Storage
BSH is classed as a flammable solid, and safety data sheets carry the signal word "Danger" with a warning that heating may cause a fire. The compound can also decompose on exposure to heat, friction or impact. Jinli's own guidance is to avoid inhalation, ingestion, and skin or eye contact, and to store the material in a dry, cool, well-ventilated place away from ignition sources and oxidizing agents.
| Area | Recommendation |
|---|---|
| Storage | Cool, dry, ventilated; sealed containers; away from heat and oxidizers. |
| Handling | Avoid dust generation, sparks and friction; ground equipment where dust may form. |
| Protection | Gloves, safety glasses and a dust mask or local exhaust ventilation. |
| Intended use | Industrial and laboratory use; a supplier SDS advises against food, drug, pesticide or biocidal use. |
Always follow the current safety data sheet supplied with your batch and your local regulations for storage and transport.
About the Manufacturer
Jiaxing Jinli Chemical Co., Ltd.is a chemical manufacturer located in the Jiaxing Port Area Chemical Park in Zhejiang, China. Its portfolio covers blowing agents, plasticizers, intermediates, disinfectants and other fine chemicals, with a focus on sulfonyl chemistry. You can read more on the About page, explore its Technology section, or follow Industry News for updates.
| Company | Jiaxing Jinli Chemical Co., Ltd. |
| Hotline | 0086-573-85580888 |
| Address | Intersection of Pinghai Road and Binhai Avenue, Jiaxing Port Area Chemical Park |
| Product page | Benzene sulfonyl hydrazide (BSH) 80-17-1 |
Frequently Asked Questions
Is BSH soluble in water?
No. It is insoluble in water but dissolves in organic solvents such as acetone.
What gas does BSH release?
Mainly nitrogen, along with small amounts of other decomposition by-products.
How do I get a quote or technical data sheet?
Use the Contact page or call the hotline above, and state your base polymer, processing temperature and target foam density so the technical team can recommend a grade.
