Three drying mechanisms
Chemical, sieve and surface adsorption desiccants from one source, so compounders can match the drying agent to polymer, process and cure system.
Industrial Mineral
Desiccants for Rubber, Polymer and Packaging Applications
Calcium oxide, molecular sieve and silica gel desiccants that remove moisture from compounds, resins and packed goods, supplied with a Technical Data Sheet and batch CoA.
PowderMasterbatch
ISO 9001 certified processes
NABL-accredited lab testing
CoA, TDS & MSDS with every shipment
Export packaging worldwide
Overview
What is Desiccants?
Desiccants are materials that capture water, either by chemical reaction or by physical adsorption. In rubber and polymer processing, even a small amount of moisture in fillers, oils or polymer can turn to steam during curing or moulding. The result is porosity, blistering, voids and poor surface finish. A desiccant added to the compound removes that water before it causes defects.
Obsidian Minerals produces three desiccant types, each working in a different way. Calcium oxide reacts with water to form calcium hydroxide, binding moisture chemically and permanently, which makes it the standard choice for rubber compounds cured at high temperature. Molecular sieve, a synthetic zeolite, adsorbs water inside pores of a precise size and is used where a non-reactive, highly selective drying agent is needed in plastics, polyurethanes and coatings. Silica gel adsorbs moisture on a large internal surface and is used to protect goods in packaging and storage.
Particle size and dispersion matter as much as capacity. A desiccant that forms agglomerates leaves dry and wet zones in the compound and can create surface specks. Our calcium oxide grade is finely milled and can be supplied as a powder or as a masterbatch, which reduces dust, slows premature reaction with air and improves distribution in the mixer. All grades are thermally stable at normal compounding temperatures and do not react with the polymer matrix.
We manufacture desiccants in Gujarat, India, under ISO 9001 certified processes, with testing in an NABL-accredited laboratory. Shipments include an SDS, Technical Data Sheet and batch Certificate of Analysis. Standard packing is 25 kg HDPE or paper bags and 1 MT or 1.2 MT jumbo bags, with moisture-barrier liners and private-label packing on request. For a combined filler and moisture-scavenging function in sealants or PVC, see our separate Desiccants Filler product.
Desiccants grades
Select a grade for its typical properties, applications, usage guidance and FAQs.
Desiccants
CaO Desiccant
Fine, highly reactive calcium oxide that binds moisture chemically, preventing porosity in cured rubber and moulded polymer parts.
Rubber & Polymers DesiccantsMolecular Sieve Desiccant
Activated zeolite powder that adsorbs water selectively in pores of fixed size, without reacting with resin or polymer.
High-performance Plastics DesiccantsSilica Gel Desiccant
Inert, high-capacity silica gel beads that protect packed goods from humidity during storage and shipping.
Packaging & Storage| Grade | Specification | Primary use | Link |
|---|---|---|---|
| Calcium Oxide Desiccant for Rubber and Polymers | On TDS | Rubber & Polymers | Specs |
| Molecular Sieve Desiccant Powder | On TDS | High-performance Plastics | Specs |
| Silica Gel Desiccant | On TDS | Packaging & Storage | Specs |
From deposit to dispatch
- 01
Raw material selection
- 02
Calcination or activation
- 03
Fine milling and classification
- 04
Surface treatment or masterbatching
- 05
Moisture-protected packing and QC
Why source Desiccants from Obsidian Minerals
Powder or masterbatch
Calcium oxide is offered as fine powder or as a masterbatch for lower dust and more even dispersion in internal mixers and extruders.
Checked before dispatch
Activity, moisture and particle size are tested in an NABL-accredited laboratory, and each batch ships with its Certificate of Analysis.
Where Desiccants is used
Desiccants — frequently asked questions
Why are desiccants added to rubber compounds?
Moisture in fillers, oils and polymers turns to steam during vulcanisation, especially in continuous curing of extruded profiles and hoses. The steam causes porosity, blisters and rough surfaces. A desiccant such as calcium oxide reacts with this water during mixing and storage, so the compound cures without moisture-related defects.
Which desiccant should I use: calcium oxide, molecular sieve or silica gel?
Calcium oxide suits most rubber compounds, where a strong chemical reaction with water is wanted. Molecular sieve is preferred in polyurethanes, plastics and coatings where a non-reactive desiccant with high affinity at low humidity is needed. Silica gel is mainly used for protecting packaged goods. We can recommend a grade once we know your polymer and process.
How much desiccant is added to a rubber compound?
Calcium oxide desiccants are usually added at about 3–8 parts per hundred rubber, depending on the moisture content of the fillers and oils, the cure method and the humidity in the plant. Higher filler loadings and hot-air or salt-bath continuous curing generally need the upper end of the range. Plant trials confirm the final level.
Do desiccants affect the physical properties of the compound?
At normal dosages, a well-dispersed desiccant has only a small effect on hardness and tensile properties, and it often improves them indirectly by removing porosity. Poor dispersion is the main risk, as agglomerates act as defects. Using a fine grade or masterbatch and adding it at the right stage of mixing keeps the effect minimal.
How should desiccants be stored?
Desiccants absorb moisture from the air, so they should be kept in their original sealed packaging in a cool, dry store and used soon after opening. Opened bags should be resealed tightly. Calcium oxide reacts with water and releases heat, so it must be kept away from water and handled as described on the SDS.
How do I request desiccant samples or a quotation?
Tell us the polymer or product, the processing and curing method, current desiccant if any, and expected monthly volume. We will recommend a grade and form, send the Technical Data Sheet and arrange a sample for trial. Pricing is quoted once the specification and packing are agreed.
What packaging options are available for Desiccants?
Standard export packing is 25 kg or 50 kg HDPE / paper bags and 1 MT or 1.2 MT jumbo (FIBC) bags, palletised and shrink-wrapped on request. Custom and private-label packaging can be arranged for volume orders.
Do you provide MSDS and technical datasheets?
Yes. A Technical Data Sheet and MSDS are available for every grade, and each shipment is accompanied by a batch-specific Certificate of Analysis.
Request a quote
Interested in Desiccants?
Tell us your application, preferred grade and volume. Our engineering team will recommend the right grade and send a datasheet, sample and quotation.
- Technical Data Sheet & MSDS
- Samples for qualification trials
- Bulk and recurring supply pricing