14 сентября, 2015 
Malyar by Morrison Barbour BSc and N Tuck PhD BSc
Typical formulations and characteristics properties for a range of non-isocyanate coatings are given below. A typical white gloss formulation based on the Michael technology might be for heavy duty, rolling stock and heavy equipment enamels:
FORMULATION 6-1: WHITE HIGH GLOSS FINISH WITH EXCELLENT
CHEMICAL RESISTANCE
|
PARTI |
|
|
GRIND PASTE |
|
|
Acetoacetyl functional acrylic (a) |
14.44 |
|
MIBK |
1.83 |
|
Solsperse 2400 |
0.33 |
|
Anti-float additive |
0.18 |
|
Tioxide TR-63 |
33.00 |
|
Bentone SD-2 |
0.82 |
|
BYK 085 |
0.32 |
|
BYK 354 |
1.20 |
|
Stabilise grind with: Acetoacetyl functional acrylic<a* |
6.55 |
|
MIBK |
1.29 |
|
Let down into: |
|
|
Acetoacetyl functional acrylic(a) Activated olefin cross linker^ |
21.19 11.73 |
|
MIBK |
5.26 |
|
Final additions: Fluorad FC-430 |
0.12 |
|
MIBK |
1.74 |
|
Total |
100.00 |
|
PART II |
|
|
COMPONENTS Base catalyst(c’ |
25.34 |
|
MIBK |
23.73 |
|
MEK |
50.93 |
|
Total |
100.00 |
|
(a) |
|
80% solution in EEP/PMA |
^100% NV (c)
10% active component in PMA
 |
 |
Specification (mixed 1:1 parts A : B)
|
TABLE 6-3: PHYSICAL PROPERTIES OF HIGH RESISTANCE HIGH GLOSS FINISH
|
This formulation exhibits superior chemical resistance for use in heavy duty, rolling stock and heavy equipment enamels.
Solsperse 2400 (Zeneca) is a polymeric dispersant. Levelling and wetting additives improve the film appearance. Bentonite is added to prevent settling of the pigment. Fluorad FC-430 reduces cratering but can have a negative effect on recoatability.
A typical formulation based on carboxyl acrylic/ epoxy acrylic technology with good resistance and durability is as follows:
FORMULATION 6-2:
SCARLET HIGH GLOSS FINISH
|
PARTI |
|
|
Organic yellow pigment ^ |
4.94 |
|
DPP red(e) |
3.70 |
|
Titanium dioxide |
2.46 |
|
Carboxyl acrylic (flexible) ^ Carboxyl acrylic (hard) |
25.22 |
|
25.21 |
|
|
Disperbyk 160 |
4.32 |
|
Baysilon OL17 (20% solution) |
0.38 |
|
Baysilon A (5% solution) |
0.15 |
|
Isobutanol |
15.15 |
|
Xylene |
1.35 |
|
Butyl acetate |
1.35 |
|
EEP |
0.34 |
|
PART II |
|
|
Epoxy functional acrylic cross linker(h* |
15.43 |
|
Total |
100.00 |
|
Hostaperm yellow H4G ex Hoescht ‘irgazin red DPPBO ex Ciba Geigy |
55% solution 55% solution 60% solution
Specification (mixed)
Viscosity (centipoise) 350
Pigment:binder ratio 0.3:1.0
Specific gravity 1.01
% vehicle solids 42.3
% total solids 49.6
Mix parts I & II and thin to spray viscosity
|
TABLE 6-4: PHYSICAL PROPERTIES (7 DAYS AIR DRY) FOR SCARLET HIGH GLOSS FINISH
|
This finish displays excellent hardness with a good degree of flexibility and impact resistance. Good resistance characteristics and high durability make this coating highly suitable for ACE, transport & rolling stock applications.
Pigmentation utilises the acrylic resin rather than the epoxy curing agent. Additives are also incorporated at this stage. Because of the nature of the functionality on the acrylic polymer, basic pigments are avoided to prevent gelation. A dispersing additive such as Disperbyk 160 helps pigmentation.
A starting point formulation for a clear overlacquer suitable for vehicle refinishing polyester basecoats is given below.
|
FORMULATION 6-3: CLEAR OVERLACQUER
|
Viscosity at 25°C 23 seconds BSB4 cup
Vehicle solids 38.6 %
Mix parts A and В just prior to spray application. The system is stable for up to 24 hours after mixing.
The epoxy copolymer is thinned with solvents to reduce its viscosity prior to the addition to part A. Synocure 890S (Cray Valley) is 55 %nvc with an acid value of 16 mg KOH/g. Synocure 898SA is 60 %nvc with an epoxy equivalent weight of 265-295. The use of a UV absorber system is essential in clear topcoats. Certain grades can lead to yellowing. A combination of 3:1 Sanduvor VSU:Sanduvor 3050 (Sandoz) is recommended for Synocure 890S based paints. Aromatic hydrocarbons with small amounts of alcohols and esters are the most suitable solvents to use for vehicle refinishing and quality maintance finishes.
A white gloss formulation with amine acrylic/ epoxy acrylic technology is given below:
FORMULATION 6-4: WHITE GLOSS NON-ISOCYANATE TOPCOAT WITH AMINE
ACRYLIC/EPOXY ACRYLIC RESINS
|
PARTI |
|
|
Grind Paste |
|
|
Amine functional acrylic w |
12.7 |
|
Kronos ТЮг 2310 |
24.5 |
|
Xylene |
5.3 |
|
Butyl acetate |
2.8 |
|
Byk 354 |
1.1 |
|
Stabilise grind with: |
|
|
Amine functional acrylic^ |
25.5 |
|
Butyl acetate |
1.9 |
|
Isobutanol |
1.2 |
|
EEP |
1.2 |
|
Byk 077 |
0.4 |
|
PART II |
|
|
Epoxy functional acrylic |
23.4 |
|
Total |
100.0 |
|
®55% solution ®60% solution |
Viscosity 18-20sDIN4
% nvc 42%
Pigment binder 0.7:1.0
|
TABLE 6-5: PHYSICAL PROPERTIES (7 DAYS AIR DRY) OF NON ISOCYANATE TOPCOAT
*1 = good; 2 = slight softening ; 3 = moderate softening |
This topcoat displays a good blend of gloss, hardness, flexibility and resistance characteristic suitable for use in VR, transport and general metal finishes.
The amine functional acrylic is used to disperse the pigment. Levelling and slip additives are also added to the grind resin. Thin to spray viscosity in a 4:3:2:3 blend of xylene:di-acetone-alcohol:isobutanol:methoxy propyl acetate.
Опубликовано в рубрике 