What is VCI desiccant?


What is VCI Desiccant?

Desiccants are generally categorized into two major types: physical and chemical moisture absorbers.

Most mineral desiccants such as zeolite, bentonite, diatomite, activated carbon, silicon dioxide, and clay desiccants are classified as physical moisture-absorbing desiccants with an average moisture absorption rate of 15-35%. Mineral desiccants absorb moisture, while only a few can absorb vapor gas due to their physical properties and structure. More specifically, desiccants with the use of zeolite and activated carbon can absorb gas effectively. There are many synthetic types of zeolites and activated carbon products specialized to absorb moisture and vapor gas together.

In addition, attapulgite is a naturally mined clay used in VCI desiccant "GVD100" production, which has a unique physical property to absorb moisture selectively compared to other types of mineral desiccant. GVD100, also known as GreenVCI Desiccant 100, and its production code name "VDPK," meaning VCI Desiccant Pack, was custom developed for General Motors Korea and patented in 2008. VDPK provide end-users with two main functions: absorbing moisture and releasing volatile corrosion inhibitor into the vapor area of the enclosed space.

On the other hand, chemical moisture absorbers can have moisture absorption rates up to 400%. For example, calcium chloride is a widely used chemical moisture absorber due to its high moisture absorption rate; however, as calcium chloride absorbs moisture, the physical property turns into a liquid state, limiting the use of calcium chloride for industrial purposes.

Therefore, to make practical use of calcium chloride, VCI desiccant "GVD300," also known as GreenVCI Desiccant 300, and its production code name "SVD," meaning Super VCI Desiccant was developed to transform calcium chloride's physical property into a gel formation as soon as it absorbs moisture while simultaneously releasing volatile corrosion inhibitors into the vapor area of the enclosed space like GVD100 but at a much higher absorption rate of 150%. GVD300 is chemically engineered with a mixture of uniquely synthesized VCI powder chemicals that has about 0.4 – 0.5 mmHg vapor pressure. This provides temporary volatile corrosion inhibiting capabilities even after calcium chloride has absorbed moisture and whether the physical property of calcium chloride is in powder and/or gel formation.

Calcium chloride desiccants should use special non-leaking yet breathable papers capable of transmitting vapor while preventing water leakage. VCI desiccant sachets and VCI film are often applied together in a corrosion protection combination package.

The patent for GVD300 was filed on June 04, 2018 and was officially registered on January 05, 2021. GVD300 is mainly composed of green VCI chemicals, food-grade calcium chloride, and super-absorbent natural polymers that will transform its original powder substance into gel formation after moisture absorption.

In conclusion, GreenVCI R&D Co., Ltd. also supply GVD100 and GVD300's green VCI raw materials separately for other VCI and/or desiccant companies to produce their own attapulgite and calcium chloride-based VCI desiccants. Various types of VCI raw material customizations are usually available for other types of desiccants upon request.
By: John Kim
Partner @ GreenVCI Solutions (USA)
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