PVDF & COATING SYSTEM
PURPOSE
Refer to approval Material of Metal cladding, Our Vendor Proposed the the PVDF Coating of Kynar with 2
system, however there are some differences of opinion. Contract mentioned as below
Finish coating shall comprise of PVF2 Plus, a double-two layer polyvinylidene fluoride applied on primer for
both exterior and interior surface on insulated or un-insulated roof and wall panels.
The "PVF2 Plus" acting as top coat, is a double coated "PVF2 Kynar 500", a 80 % or 80/20 fluorocarbon
(polyvinylidene fluoride) applied to the special steel substrate in accordance with the requirements of the metal
siding and roofing fabricator but conform with the metal sheet requirement as stipulated on previous section.
Total dry film thickness of min. 46 microns composed of both an epoxy corrosion inhibitive premier and the top
coat PVF2 plus Kynar 500
Contract document caused several question regarding difference opinon and description between the Material
specification, Coating Finish and data sheet availability from Manufacturer.
BRIEF HISTORY OF PVDF RESIN
In the Chemistry , PVDF is the abbreviation for Polyvinylidene fluoride or polyvinylidene difluoride, which can
also be referred to as PVF2. This polymer is part of a class of materials known as fluorocarbons or
fluoropolymers, which are characterized by high thermal stability and excellent chemical resistance.
Based on history, PVDF is Polyvinyl fluoride film that Invented and patented by DuPont Corporation in 1948.
Pennwalt chemical acquired the rights and developed the licensing program allowed the first widespread
commercial use as pigmented liquid coating. This coating was sold under the name Kynar 500® trade name in
the mid 60’s. In the 80’s Pennwalt was acquired by Elf Atochem (now called Arkema ,
https://kynar500.arkema.com/en/). The Federal Trade commission mandate that Elf Atochem divest one of its
production facilities. Ausimont, USA (Now Solvay Solexis) acquired it and become the second major supplier
of PVDF Coatings (With trade name Hylar® 5000).
KYNAR 500 FAMILY
Kynar 500® FSF® and Kynar Aquatec® PVDF resin family includes:
a. Kynar 500® FSF®
b. Kynar Aquatec® ARC
c. Kynar 500® Plus
d. Kynar Aquatec® FMA-12
e. Kynar® ADS II
f. Kynar Aquatec® CRX
g. Kynar® SL II
Based on our vendor, The material Described in the contract are Kynar 500® Plus widely acknowledge in the
market and also used by our vendor.
COATING SYSTEM
In the common Application practices, PVDF o/ PVF2 Coating system for best protections is applied with 2
coating system for solid color and 3-4 coating system for metallic color which is :
1. 2 Coat system that which consisted primer and Top coat. This system is can only use non metallic
color/ Solid color. Thickness nominal for this system are 1 mill (25 micron)
2. 3-4 coat system that consisted primer, color coat, and clear coat with Nominal thickness 1,5 mill ( 37
micron)
The pretreatment (Metal Coating) is not considered one of the paint coats. (Data Taken from Alucobond
website)
Standard MRCMA T-20 also mentioned, to reach maximum protection, it is common to coat faced and backing
sheet with PVDF/PVF2/ DFT Coating thickness for front faced Nominal is 25 micron / 1 mill and Backing faced
nominal is 15-18 micron.
CONCLUSION
The Contract “The "PVF2 Plus" acting as top coat, is a double coated "PVF2 Kynar 500", a
80 % or 80/20 fluorocarbon (polyvinylidene fluoride)” describes the cladding is use 2 system coating with
specification of PVF2 / PVDF system with brand name Kynar 500 with series Kynar 500 plus,
Text mentioned in contract in the sentenced “ Total dry film thickness of min. 46 microns composed of both an
epoxy corrosion inhibitive premier and the top coat PVF2 plus Kynar 500 “, is should be acknowledge as top
coat of PVF2 Kynar 500 Plus. plus here mentioned the range of family of the resin material, not refer to
another coating.since the double layer top coat is not applicable and cannot found in data sheet paiting
Total dry film mentioned in the Contract is total DFT face and backward of the metal cladding.
ATTACHMENT
a. Kynar PVDF Resin Family (https://kynar500.arkema.com/en/product-information/fluorosurfactant-free/)
b. Alucobond Paint Finishes data sheet (https://www.alucobondusa.com/colors-and-finishes.html)
c. Rare-Manufacturing-What-is-PVDF
(https://www.raremanufacturing.com/wp-content/uploads/2015/09/Rare-Manufacturing-What-is-
PVDF.pdf)
d. Kynar 500 FSF Specification
(https://kynar500.arkema.com/files/live/sites/hpp_kynar500/files/downloads/kynar500-
specifications/kynar-500-fsf-specifications.pdf)
