11 сентября, 2015 
Malyar Ultraviolet curing grades of aerobic acrylics yield tough, impact-resistant, structural adhesives with tensile strengths up to 3000 psi when joining metal, plastic, glass, ceramics, and other substrates. Adhesive potting to 1 in. can be produced in a single exposure to high — intensity UV light. Transparent optical adhesives are also derived from this technology.
Figure 1 showed steel adhesion tensile strengths of a typical aerobic adhesive cured with either activator or UV light. The ability to use multitype curing technologies to achieve structural adhesion strength greatly expands design capabilities and helps design in a more optimum, a more productive, assembly process.
Surface dryness and depth of cure are dependent on both the lamp used and the individual formulation. High intensities are required for the most rapid and deepest cures. A potting grade UV aerobic will cure to 4 in. in 30 s under a 100,000 microwave/cm2 mercury vapor lamp. Table 6 shows curing times with various lights. The optical region of the electromagnetic spectrum is defined into UV, a narrow band of visible light, and a belt of infrared radiation, as shown in Fig. 8. An exploded view of the UV spectrum with
|
Intensity at |
Seconds to cure 1 |
Seconds to cure 1 |
||
|
350-400 nm |
(2-mil gap between |
(1/8" deep wire tack)a |
||
|
Source |
Wavelength |
(watts/cm2) |
glass slides)a |
|
|
Sunlight |
Full spectrum |
Very low |
10-30 |
Not recommended |
|
Mineral light |
350-400 nm |
100-7000 |
5-20 |
15-100 (higher intensities only) |
|
Black light 275-watt |
Full spectrum |
5000-7000 |
1-10 |
5-30 |
|
consumer style sunlampb |
+ heat |
|||
|
Industrial-grade |
300-400 nm |
5000-10,000 |
1-15 |
5-30 |
|
mercury arc lamp type I |
+ visible light |
|||
|
Industrial-grade |
Full spectrum |
1,500,000 |
0.5-4 |
2-10 |
|
mercury arc lamp type IIc |
+ heat |
|||
|
Pulsed xenon arc |
Full spectrum |
Very high |
Fast |
1-5 |
|
lamps; solar simulatorsc |
+ heat |
|||
|
Dymax ‘‘worker |
300-400 nm |
50,000- |
Fast |
1-5 |
|
friendly’’ UV lamps |
+ visible light |
150,000 |
|
aSpeed of cure varies according to formulation. bShielding recommended. cShielding required. |
Copyright © 2003 by Taylor & Francis Group, LLC
|
Figure 8 (Top) Optical region of the electromagnetic spectrum is defined into ultraviolet, a narrow band of visible light, and a belt of infrared radiation. (Bottom) An exploded view of the UV spectrum with absorbance curves for Dymax UV adhesives compared to typical UV inks and coatings. X Maximum = that point at which maximum absorption of UV energy occurs. |
absorbance curves for Dymax UV adhesives as compared to typical UV inks and coatings is also shown in Fig. 8.
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