|Product type||Automotive aftermarket in glass care; other car care: Car Washes, Waxes, Bug & Tar Removers, and Headlight Restoration Kits.|
|Owner||ITW Global Brands, division of Illinois Tool Works (ITW)|
|Previous owners||Pennzoil-Quaker State Company dba SOPUS Products|
|Tagline||Outsmart the elements®|
Rain-X is a synthetic hydrophobic surface-applied product that causes water to bead, most commonly used on glass automobile surfaces. It was introduced in 1972 by Howard G. Ohlhausen of the Unelko Corporation. 
The brand has since been extended to a range of automotive and surface care products, including wiper blades. It is currently owned by ITW Global Brands.
Rain-X Online Protectant was introduced to carwashes in 2005. It is a water-based compound that is applied to the entire car's surface, working much like consumer grade Rain-X products.
Due to its general water repellent properties, the original Rain-X formulation is used in a wide variety of consumer, commercial and industrial settings. The primary use of Rain-X is for automotive applications. Commercially sold "Original Glass Treatment" is the original and most well known Rain-X branded product. It is a hydrophobic silicone polymer that forces water to bead and roll off of the car, often without needing wipers. It is sold in 3.5 or 7 oz. bottles, or as wipes or towelettes.
The original coating has also had use in military and other government settings. The Australian military examined the effect of application of Rain-X and similar products to submarine antennae to improve signal transmission, although other coatings had longer lifespans when submerged in salt water.
Ski and snowboard enthusiasts use Rain-X as "wax" to effectively overcome sticky wet snow common in spring conditions. While skiing or riding on mountains with hard snow pack, the heat of the sun changes snow conditions starting on the lower slopes. Skis may suddenly slow down, throwing one off-balance, because of a change in surface tension, a sort of "sandpaper effect." Rain-X is applied to the ski or board base, or to the bottoms of ski boots to reduce, or eliminate snow "wedges" that interfere with proper mounting into ski bindings.
Rain-X's primary active ingredient are polysiloxanes, the primary one being hydroxy-terminated polydimethylsiloxane. The polysiloxanes have functional groups that bind to the hydroxyl group of the glass surface. Rain-X's submitted safety documents state that Rain-x is a composition of acetone and water, but the exact ratio is a trade secret.
Between 1997 and 2011 Rain-X was marketed by SOPUS Products, a subsidiary of Pennzoil-Quaker State, itself a subsidiary of Royal Dutch Shell. On March 1, 2011, Illinois Tool Works acquired SOPUS' car care business.
Industrial Rain-X products were produced by Ecolab and used in carwashes and other industrial applications. Ecolab sold its vehicle care business to Zep, Inc. on December 1, 2012. The sale also included the Armor All Professional, Black Magic, Blue Coral, Niagara National, Washtronics, and Zep Enviroedge brands.
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- "Illinois Tool Works Acquires SOPUS Products' Car Care Business". News release. PRNewswire via COMTEX -- ITW website. 1 March 2011. Retrieved 20 March 2017.
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- "Zep Inc. Completes Acquisition of Ecolab's Vehicle Care Division". Zep, Inc. 3 December 2012. Archived from the original on 10 December 2014. Retrieved 8 December 2014.
- Official website of the Rain-X brand
- Official website of the owner company, ITW Global Brands
- Official website of the parent company, Illinois Tool Works (ITW)