Views: 172 Author: Site Editor Publish Time: 2018-11-02 Origin: Site
Pre-painted steel coils——PVDF coating type:
PVDF is short for Polyvinylidene fluoride.Due to the strong bond energy between the chemical bonds and chemical bonds of PVDF, the coating has very good corrosion resistance and color retention,which make PVDF coating be the most advanced product in the color coating steel construction industry.The molecular weight is large and the direct bond type structure, so in addition to chemical resistance, mechanical properties, ultraviolet resistance and heat resistance are also prominent.
PVDF coating has an outdoor weather resistance of 20-25years.The coating resists urban dust, acid rain, hot sun, cold winds in the Arctic, and still maintains a beautiful appearance and integrity.It can be applied to a variety of harsh outdoor environments, especially those that require resistance to atmospheric pollution and durability or cold, heat and strong sunlight throughout the year.
Coating structure details:
PhuizerColor VF-20:Hot dipped galvanized steel coils,according to JIS G3302,Zinc coating 275 g/m²；
ColorFan VF-20F:Hot dipped galvalume(5% aluminum coating added in),according to JISG3317,Zinc coating: 275 g/m²;
ColorLume VF-20L:Hop dipped galvalume(55% aluminum coating added in ),according to JIS G3321,AZ coating:150 g/m²,standard thickness:0.576mm,other thickness could follow customers’ requirement.
Coating system with double-sided two-coating
According to different production line equipment,the Bonderite surface treatment agent produced by Chemetall S.A. of France is appropriately selected to form a surface-formed film with excellent density and excellent corrosion resistance on the surface of the coating.
Using high-performance special anti-corrosive primers, such as epoxy resin, polyurethane resin, can also be made according to the environment of the customer's project area.
Using high-performance PVDF coating with over 70% KYNAR 5000R or HYLAR 5000R,film thickness 20-25μm.
Top coating color & gloss:
Color could be customized;
Top coating gloss is typically 25%(60° reflection angle,according to ASTM D523)
Back primer coating:
Using highly corrosion resistant Polyurethane(Also called PU),film thickness:2μm.
Using good corrosion resistant epoxy resin coating or polyester resin coating,film thickness:7-10μm.
Back coating color & gloss:
Back coating color is usually using beige,grey or white grey color.Back coating gloss is typically 25%(60° reflection angle,according to ASTM D523).
We could add one layer of strippable film on the top coating,in order to reduce steel coils’ damage,when goods delivery,storage and processing.This strippable film need to be ripped off within one month after installation.And please rip off this film within 5 months,to avoid difficult to peel off the film,when steel coils are only under storage.
●Pencil hardness( ASTM D3363):Over F
●Impact test(ASTM D2794):The impact was made by a 12.7 mm diameter impact head, and used 500g heavy hammer to impact at 50cm height, and then quickly peel off at a 180°angle with 3M #600 tape, and the painting film adhered well without any peeling.
●Erichsen test(ASTM E643):At speed 12±6mm/min to do 7mm stroke after molding,and then quickly peel off at a 180°angle with 3M #600 tape, and the painting film adhered well without any peeling.
●Bending test(ASTM D4145):Cut sample and make it under 180° angle,then make the inner diameter of the curved arc 3 times the thickness value (3T),and then quickly peel off at a 180°angle with 3M #600 tape, and the painting film adhered well without any peeling.
●Abrasion resistance,Falling sand(ASTM D968):The amount of falling sand is above 40KG.
●Solvent resistance(ASTM D5402):Using gauze which is dipped with M.E.K. or toluene,and wipe back and forth 100 times on sample surface with 1KG strength,and no substrate was showing.
5,Accelerated corrosion and weathering test:
●Salt spray test(ASTM B117):After 1000 hours’ salt spray test,there is no any red rust, foaming (above 6F), and corrosion of the coating happening part 5mm away from the score(Un-scribed area).
Note:This is for top coating,for back coating is 300hours.
●Weathering Test-QUV(ASTM G53):After 2000hours,there is no significant color change and chalking.
(Dew cycle weatherometer ASTM D3361)After 1000hours(500cycles),no any significant color change and chalking.
●Chemical resistance-spot test(ASTM D1308):No any significant changes after 30days with 5%HCL on surface;No any significant changes after 30days with 5%H2SO4 on surface;No any significant changes after 30days with 5%NaOH on surface.
6,Handling and forming:
In order to avoid damage to the surface of the product, the product must be handled carefully during handling, transportation, molding and installation. Improper use of molding lubricants will affect product characteristics and cause surface contamination. Do not use if not necessary.
In any case, the steel coils should never be stored or stored in a damp environment.Because the action of the capillary will suck moisture into the surface of steel coil, moisture gas or water will not evaporate normally, which may lead to deterioration of product characteristics, shorten the expected service life, and affect the appearance of the product. The storage for related products,such as color corrugated steel sheets,sandwich panels,etc.,also requires special attention to this problem.