What is Zinc Stearate ?

Zinc Stearate is a chemical substance that has a white, fluffy, powdered appearance and is usually formed from a combination of Stearic acid and zinc oxide. It does not have a strong odor, although traces of a slight fatty acid scent are not uncommon Zinc Stearate is a compound of long-chain fatty acids with Zinc attached to it. Zinc Stearates are insoluble in polar solvents (like alcohol & ethers), but more soluble in in aromatic compounds and chlorinated hydrocarbons when heated.

It is a Zinc Salt of Fatty Acids [Zinc Stearate chemical formula is Zn(C17H35COO)2 ]. Also known as Zinc Octadecanoic acid. And it has the molecular mass of 632.35 g mol−1

Synonyms of Zinc Stearate are “Zinc Soap”, “Zinc Salt of fatty acid”, “Zincum”,  “Zinc Octadecanoate”, “Zinc distearate” etc.

It is the most powerful mold release agent among all metal soaps. It contains no electrolyte and has a hydrophobic effect. Because of this versatility, this substance is used by many different types of companies, from plastic industries to concrete manufacturers. Its main application areas are the plastics and rubber industry where it is used as a releasing agent and lubricant which can be easily incorporated.

Zinc Stearate can be manufactured from different methods, i.e.,

  • Precipitation method : Indirect method.
  • Direct process : Zinc Oxide and Stearic acid reacts directly to produce Zinc Stearate. Temperature conditions are controlled and water acts as a catalyst to fasten the process. This process is not commercially viable.
  • Fusion process : High shear process under controlled temperature and pressure condition.
  • VM Process : inhouse developed process, thanks to our R&D department. From this, we are now able to produce highest quality of Zinc Stearate at most competitive price.

Zinc Stearate properties:

Zinc Stearate is hydrophobic, lipophilic, non-sticky, highly soluble in the nonpolar medium of polyolefins as well as in aromatic compounds. The physical properties of lubricity, hydrophobicity, compatibility and melting point are all important in providing the necessary performance. It is also emulsifier in the toiletries and cosmetics areas. One of the unique propoerties of Zinc stearate which makes it different from other metal stearate is that is has a sharp melting point (in other words, Zinc stearate liquefies on melting). This makes it a very essential mineral in our day-to-day life as well as in various industrial applications.

Zinc Stearate has manifold range of use due to its unique properties, i.e.,  lubricating properties, separating properties, water repellence, gelling capacity, stabilizing effect, foam inhibition, acid scavenger, and melting point etc. The zinc Stearate reduces the number of high energy sites available for bonding at the metal surface. As the metal surface energy is reduced, mold release is improved.

It is widely used as a release agent for the production of many kinds of objects rubber, polyurethane, polyester processing system, powder metallurgy. These applications exploit its “non-stick” properties. In cosmetics, zinc stearate is a lubricant and thickening to improve texture. It is an “activator” for rubber vulcanization by sulfur and accelerators. As discovered in the early days of vulcanization, Zinc has a beneficial effect on the reaction of the sulfur with the polyolefin. The Stearate is a form of zinc that is highly soluble in the nonpolar medium of the polyolefins. Being lipophilic, it functions as a phase transfer catalyst for the saponification of fats.

Zinc Stearate Chemical Properties/Composition :

Zinc as ZnO (%) : 11.5 – 13.0%
Free fatty acid : 0.5%
Moisture (%) : 0.5 max.
Ash Content (%) : 12.5 – 13.5%

 

Zinc Stearate  Physical Properties :

Appearance : Soft, White powder
Bulk density : 1.095 g/cm³, solid
Melting Point : 120–124 °C
Boiling Point : decomposes
Solubility in water : insoluble
Solubility in Benzene : Slightly soluble

 

 

Metal Stearate lining up, coating surface for mold release

Metal Stearate lining up, coating surface for mold release

Zinc Stearate Industrial Applications& Uses :

  • Zinc Stearate in Rubber Industry: anti-sticking and mold release agent. Zinc stearate also acts as an “Activator” in cross linking the natural raw rubber in rubber vulcanization process.  It can be used as a drying lubricant or dusting agent for rubber products.
  • Zinc Stearate in Plastics Industry : lubricant & release agent. it also improves the gelation speed with the basic lead salt and lead soap. For PE & PP, Zinc stearate is used as halogen absorbing agent, it can eliminate the bad effect of residual catalyst to the resins color and stabilizer in the resins.
  • Zinc Stearate Paint & Coating Industry : pigment suspension, improve grindability and matting. In the paint industry where zinc stearate is added to lacquers and paint coatings for use as a flatting and sanding agent.
  • Zinc Stearate Cosmetics Industry : production of creams and ointments; also used to control sweat and maintain makeup. In cosmetics, zinc stearate is a lubricant and thickening to improve texture. In cosmetics, The Stearate salts are generally used for their lubricating properties. They also help to keep emulsions from separating into their oil and liquid components. The Stearate salts increase the thickness of the lipid (oil) portion of cosmetics and personal care products and reduce the clear or transparent appearance of finished products.
  • Zinc Stearate Pharmaceutical Industry : in dragee preparation & tablet pressing. Zinc stearate has antiseptic, astringent and topical protective properties, due to which Zinc stearate can be used as a water-repellent, a protective agent used in powders and ointments in the treatment of eczema, acne, and other skin diseases.
  • Zinc Stearate Paper Industry : Coating agent for high quality papers. Zinc stearate coating prevents clogging in papers.
  • Zinc Stearate Metal Industry: lubricants for powder metallurgy, wire drawing & tubing.
  • Zinc Stearate in Concrete industry : For concrete manufacturing, it is mixed as an additive for waterproofing concrete.
  • Other Uses : washing powder, building materials, textiles, Inks, wax compounds etc. As a chief ingredient in “fanning powder”, it is used by magicians performing card manipulation to decrease the friction between the cards.

Zinc Stearate Price in India (Our suggested talc grades):

Our Zinc Stearate product grades are produced from the highest quality Zinc Oxide and Stearic Acid. A variety of Zinc Stearate is manufactured to cater different industrial requirements.

Zinc Stearate Grades VZ – Plastics VZ – Rubber VZ – Paper VZ – PVC
Product Name Premium quality ZnSt2 for Plastics Industrial grade ZnSt2 for Rubber industry ZnSt2 for paper coatings Zinc Stearate for Polyolefins
Zinc Content (%) 10.8 – 12.5 11.5 – 13.5 11.2 – 13.0 12.0 – 13.0
Total Ash (as ZnO) 11.5 – 13.0 13.0 – 14.0 12.8 – 13.8 12.8 – 13.5
Moisture (%) 0.5 max 0.5 max 0.5 max 1% max
Free Fatty Acid (%) 0.5 max 0.5 max 0.5 max 0.5 max
Soluble Salts (%) Nil Nil Nil Nil
Melting Point (°C) 120-122 120-124 118-124 120-124
Fineness 700 mesh 325 mesh 325 mesh granules
Sieve residue (%) 0.2 0.2 0.2 -
Applications Very fine powder for mold releasing in plastics Fine powder for rubber products and plastics Dusting / coating agent in paper, rubber and plastics Very low dusting granules

 

Packaging Details :

1. 20kg/bag, white paper bag or composite kraft paper bag(inside with PE plastics bag).

2. Should storage and transport under shady, cool and ventilated environment ; Avoid acid, alkali and corrosive substances. Keep it away from the humidity, hotness, fire and corrosion.