Benefits of PVDC for Corrosion Inhibition

Posted by Lubrizol Performance Coatings Team on 09/18/2019
Corrosion is a destructive erosion caused by chemical or electrochemical reactions between metals and the surrounding environment. It is a type of destruction that quietly occurs over time. The effects of corrosion can be significant, causing the consumption of metal materials and damage to the structure of metal equipment, shortening service life. Severe corrosion can also cause sudden disasters and environmental pollution accidents, such as corrosion of oil pipelines. In fact, in China alone, the economic losses caused by corrosion are estimated about 3% to 4% of the total economy.
 
There are many ways to prevent or slow corrosion, such as the use of electrochemical protection (anodic/cathodic protection), and the use of film as a barrier against the corrosion media like moisture and oxygen. One of the most common and economic methods for corrosion protection is to apply an anti-corrosive coating system onto the metal, which forms a barrier between the metal and the corrosion media. Additionally, electrochemical protection can be added to the coating by adding zinc and similar materials.
 
A variety of anti-corrosion coatings are available globally with good performance capability for corrosive environments. ISO 12944-52 lists examples of generic type of paints for corrosion protection of steel structures, like alkyd paints, acrylic paint, ethyl silicate paints, epoxy coatings, polyurethane coatings, etc. In recent years, with increasing emphasis on environmental protection globally, various policies have been enacted that restrict VOC emissions. Anti-corrosion coatings have been developed in the direction of sustainability and environmental protection, and the development of various water-based anti-corrosion coatings has been promoted.

 

As a novel solution, water-borne PVDC (polyvinylidene chloride)-acrylic co-binder has been developed and applied in water-borne anti-corrosive primers, as one of the alternatives to water-borne epoxy primer. PVDC provides excellent barrier to corrosion media, both oxygen and water vapor. Its co-polymerization with acrylates synergizes its excellent barrier properties and adhesion as well as uniform film formation with durability and flexibility properties of the acrylates. The co-binder performs well as an anti-corrosion primer, especially for low to medium atmospheric corrosivity environments. It offers advantages over the conventional water-borne epoxy primers, such as fast-drying properties, 1K, room temperature curing, etc. It is used in water-borne anti-corrosive coatings that are low VOC, APEO-free, and meet emerging environment requirements.

Oxygen and Water Vapor Transmission Rates of Various Polymer Technologies

 

Chemistry of the film

 Oxygen Transmission Rate
(cc/m2.day.atm)

Water Vapor Transmission Rate
(g/m2.day)

 PVDC  1 1
 EVOH  1 75
 PET  80 22
 PVC  200 5
 HDPE  2900 22
 PP  2000 14
 
 
 

Contact Lubrizol to learn more about the benefits of PVDC for corrosion inhibition or to discuss your specific formulation challenges.

 

 

 
Lubrizol Performance Coatings Team

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