An intro on how Polyurethane is manufactures and how they are used as coating material, their testing standard, uses and application

1. Pros and Cons of polyurethane coating
Vignesh Dhanabalan (12mtech13)

2. What is polyurethane/synthesis of
polyurethane
 Isocyanate/di-isocyantae + polyol + catalyst + surfactants + blowing
agents
 One component and two component system
 Isocynate -> aliphatic - > uv resistant
 -> aromatic - > hydrolitic resistant

3. Reactors during Polymerization
 Types of polyols
 Rigid polyurethane -> chain extender + isocyanate + high cross linking agent
 Flexible polyurethanes -> longer chain extender + isocyanate + low cross linking
agent
 Property enhancer
 Thermal behavior
 Compressive nature
 Acoustic nature
 Blowing agent
 Open cell structure – 3.6 to 3. 8
 Closed cell structure – 6.0 to 7.14
 Surfactants
 Hydro philicity/phobicity nature

4. Polyols
 Polyether polyols contain the repeating
ether linkage –R-O-R- and have two or
more hydroxyl groups as terminal
functional groups.
 Water soluble polymers with a
molecular weight between 200 and
14,000.
 Shorter linkages
 Rigid polymer
 Polyester polyols have repetitive ester
linkage and are also called as
elastomeric polyols.
 Aliphatic and Aromatic polyols.
 Flexible polymer with better
compressive nature.
 Longer linkage
 Comparatively biodegradable.
Ether polyols

5. Behavior of Polyurethane (properties)
 Thermal nature (-30 to 90Cº) sustain upto 250ºC , 80% at high
preassure
 Effect of water on thermal behavior of foams - λ = 0.58 W/(m·K)
 Degradation of foam material – Damage to cell structure at cyclic loading
 Compressive nature of polyurethane foam
 Effect of cyclic loading – 3% energy for deformation
 Crack formation – 320Kgm-3
 Tensile behavior
 Chemical nature
 Adhesivity

6. Polyurethane coating and application methods
Dual nozzle spray gun Rod mayor method
Immersion methodSurface lamination
Knife coating
Floating knife
Extrusion
Calendaring
Curtain
coating
Gurave
coating
Reverse roll
 Square
 Tapered
 Round
 J-blade
 Footed j-

7. Evaluations of coated material
• Either increase or decrease
• Corrosive nature of materialsTensile strength
• Skin type formationShear behavior
• Necessary parameter for durability of coated film as well as
composite materialPeel strength
• Structural design
• X-ray, 3d scanning, SEM analysis
Dimensional stability
and cell structure
• DTA – Differential thermal Analyzer
• DTG – Differential thermogravimetry
• TG - Thermogravimetry
Thermal transmition
• Determines visco-elasticity of the materialCreep behavior

8. Testing standards
S.no Tests Standards
1 Abrasion resistance ASTM D-3389, BS 3424
2 Flexibility IS 7016, ISO5979
3 Stiffness IS 649
4 Air permeability BS 3424
5 Water vapor permeability x ASTM E 96-80
6 Water repellency Spray rating IS390, AATCC 22-1996
7 Cone test IS 7941
8 Coating adhesion BS 3424, ASTM D-751, IS 7016
9 Color fastness to dry and wet fastness BS 3424, IS 1259
11 Penetration to chemical hazard ASTM F 739-96
12 Electrical resistivity AATCC 76-1995
13 Penetration to blood borne pathogens ASTM F 1671-97b

9. Application of polymeric coating on end product
Acoustic insulation Metal coating Sealant
Wood laminates Filter medium Floor
polishes
Insulating
tubes
ETC…………

10. Advantages and limitations
Multiple layer coating
Resistive to chemical and
flame
High capital
Low
maintenance
and after
care
Evolution of gases during
VOC

11. Untraped research works
 To inhibit thermal insulative value to structures using it as a composite
structure.
 Redesign infrastructural components with light weight polyurethane casing .
 Usage of biodegradable castor based polyols for degradable polyurethanes.
 Evolution of low thermal effects.
 Effective waterproof breathable coatings for fabric surfaces
 Reduce capital cost
 Polyurethane vascular prosthesis carrying a dipyridamole is under research.

12. Conclusion
 Polyurethane that was synthesized accidentally has found a viable
replacement for lightweight high stiffness material.
 Multi functional properties are able to achieve with less use of catalyst.
 Their usage has been seeing the down face basically because of
environmental concern over the use of fossil based raw material.
 The use of natural oil for its synthesis is under going research work
which has shown good results.

13. Bibliography
 Sen kumar.A, Coated textiles principle and application second edition CRC press ISBN 978-1-4200-
5345-6, 2007.
 Smith William.C, smart textile coating and laminates, wood head publications, ISBN 978-1-84569-
379-4, 2010.
 Chapman and Hall, surface coating and raw material vol 1, 1993.
 Maria-carmen loghin, irina ionescu, pulferia nicolaiov, ionuț dulgheriu, thermal characterization of
coated fabrics, unpublished work.
 http://commercialroofinglosangeles.wordpress.com/2012/02/02/coat-it.
 http://www.swagathurethane.co.in/polyurethane-coating.html
 http://www.foamroofing.com/aboutspf.html
 W.-y. li and C.-j. li, Effect of annealing treatment on the microstructure and properties of cold-sprayed
cu coating, thermal spray , internal thermal spray conference. 2005
 Galliot.C, Luchsinger.R.H, The shear ramp: a new test method for the investigation of coated fabric
shear behavior, empa - swiss federal laboratories for materials science and technology, center for
synergetic structures, ueberlandstrasse 129, ch-8600 duebendorf, Switzerland.
 Jia.Y, Jiang.M.Z, Gong.X.L, Zhang.Z Creep of thermoplastic polyurethane reinforced with ozone
functionalized carbon nanotubes, eXPRESS Polymer Letters Vol.6, No.9 (2012) 750–758.
 http://www.baycoll.com/BMS/DB-
SC/BMS_RSC_CAS.nsf/id/PortalEN_Properties_of_polyurethane_coatings