Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor
Patent
1995-11-30
1998-09-08
Sells, James
Adhesive bonding and miscellaneous chemical manufacture
Methods
Surface bonding and/or assembly therefor
156228, 1562722, 1562737, 156324, 1563798, B32B 3100
Patent
active
058040137
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The invention concerns processes for manufacturing plastic laminates with metal laminae, especially for printed circuits.
The term plastic laminates usually means sheets made by stable association, generally by pressing, of several layers of plastic materials on a base of paper, fibreglass fabrics or other types of prepreg, in any case insulating.
In manufacturing printed circuits a metal lamina, normally of copper, is made to adhere to one or both sides when pressing takes place.
In this way a pile of packages, all practically the same, is formed each package comprising a number of impregnated sheets of plastic materials and copper laminae placed on the two sides of the package respectively.
A metal sheet, of stainless steel or some other type, is placed between each package and the pile put in a multi-plate press which supplies heat and pressure at the same time.
Presses of this kind are generally complex and of no great efficiency because of the high temperatures and pressure levels needed, of the number of plates they contain, of having to produce heat and pressure in well-defined and accurate sequences, of the need to create--by conduction--uniform temperatures throughout the packages in the pile of which only those packages at top and bottom can be in direct contact with the heating plates.
Propagation of heat by the press plates to the piled-up packages and of refrigeration units is severely hindered by their having to pass through prepreg components,which are well-known to be very poor conductors, in the packages at the top and bottom of each pile.
The number of plates in the press not only complicates its structure but also delays loading and unloading of packages as well as creating problems for short runs on account of having to amortize their higher costs.
The machines and equipment for the manufacture of continuous plastic laminates are well known.
A multi-composition band is prepared including bands of copper and others of prepreg. Machinery comprising a hot press maintain adequate pressure on the multi-composition band and move it forward at the same time at a suitable speed for applying to the material a heat-pressure cycle for a sufficiently long time to transform it into a rigid plastic laminate.
Even with this process machine output is adversely affected by the presence of heating plates and by the difficulty of applying pressure simultaneously to several of such bands.
The process does not therefore usually give the results expected from a continuous system particularly as it is a complex matter to apply heat and pressure to moving parts.
SUMMARY OF THE INVENTION
Subject of the invention is a process for manufacturing plastic laminates with metal laminae, especially copper, and intermediate layers of prepreg, in a cold press with endothermic heating applied by electric current.
The metal laminae and prepreg elements are made from a multi-composition band formed of two metal strips, especially copper, and of intermediate bands of prepreg.
One or more of said multi-composition bands pass, superimposed, through the press cyclicly and continuously unwinding from reels on a feeding device and are pressed down in cycles during closure of the press.
Having completed the pressing cycle, while the press is opening the multicomposition bands, now transformed by the press into plastic laminates, move forward for a length substantially that of the press itself, emerging from it and being replaced by more multicomposition bands, and so on.
In this way continuous lengths of rigid plastic laminates are obtained and can be cut to any particular one desired.
The bands of prepreg are narrower than the laminae and they occupy an axial position in relation so said laminae.
This means that the laminae project from the two sides of the bands of prepreg.
Among the multicomposition bands lying above in the press, intermediate sheets of insulating material are inserted and to each of these, one after another, on a lateral edge parallel to the multicomposition bands and on alterna
REFERENCES:
patent: 4062718 (1977-12-01), Hay, II
patent: 4220847 (1980-09-01), Focke et al.
patent: 4963208 (1990-10-01), Muncy et al.
Cedal S.r.l.
Sells James
Striker Michael J.
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