Radio frequency curing

A primerless adhesive designed for heat fixture or radio frequency cure assembly, whilst also offering long bondable open times at room temperature. Ideal for high performance composites, including automotive and personal watercraft assembly. 

Pizzi A 1978 Wattle tannin adhesives for radio-frequency curing. J Appl Polym Sci 22 3603 - 3606... 

A unique process for chemical stabili2ation of a ceUular elastomer upon extmsion has been shown for ethylene—propylene mbber the expanded mbber obtained by extmsion is exposed to high energy radiation to cross-link or vulcani2e the mbber and give dimensional stabUity (9). EPDM is also made continuously through extmsion and a combination of hot air and microwaves or radio frequency waves which both activate the blow and accelerate the cure. 

Curing with Microwave or Radio-Frequency Processing Equipment... 

It is further added that Rife s Beam Ray Instrument (the radio frequency device) was clinically tested in a University of Southern Califomia study on 16 terminally ill cancer patients in 1934, all supervised by a panel of medical experts. Fourteen were pronounced cured within 70 days the other two required 20 more days before being clinically cured. Nevertheless, Rife s work was discounted by certain of the medical establishment, who succeeded in restrictedly defining a virus only as a particular microorganism that proliferates by modifying the genetic machinery of... 

Actually, this suggestion serves to introduce the subjects of microwave and radio frequency radiation. RF radiation is being used to cure adhesives on laminates for furniture and for drying coatings, while microwave has been used to vulcanize rubber, convert plastics, and dry inks. 

Radio frequency radiation and microwave radiation cause coatings to dry or cure by thermal activation. The most important mechanism of activation involves rotation of polar molecules so as to align their dipoles in an electric field. The rate at which electrical energy can be dissipated in a dielectric material is proportional to the frequency of the energy and to the square of the electric field strength. The relationship is expressed in the equation (12)... 

There are two primary pultrusion processes. In one method, the pultrusion passes through a long heated die or oven for cure. This is called the tunnel oven process. In the second method the composite is cured with radio frequency energy. This causes cure in a much shorter period of time. 

The curing rate of the resin in the heated die must be carefully controlled. Most of the resins used are exothermic (give off heat while curing). Too rapid a curing results in voids and cracks whereas, too slow a curing produces a poorly cured product with poor physical properties. Dies used in pultrusion are usually quite simple and inexpensive. Dies are heated electrically or with radio frequency (RF) generators up to 10 kW at 100 MHz. When RF heating is used, the dies are made of Teflon. 

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