DE3002227A1 - Printed circuit board waste material recovery - cutting up and granulating with metal separation followed by grinding remaining granules and forming impregnating paste - Google Patents

Abstract

Waste material is recovered for making printed circuit boards. The material is recovered from copper covered and non-covered laminated plastic material. The waste material is cut up and granulated and the heavy part including the metal is separated by an air current. The metal is separated from the coarse particles by screening. The coarse and fine non metal powder is combined and milled to a fine powder, and dissolved in a resin solution and used as a paste for impregnating the paper layer. The waste material is initially granulated to a grain size of less than 700 microns. The non-metal material is separated as finer particles of up to 300 microps in size, and the fine powder has a particle size of about 100 microns. After dispersion with the resin solution, its max. grain size is a max. of 50 microns.

Description

Process for the recovery of laminated and uncovered

th laminate waste The invention relates to a method for the recovery of non-ferrous metal and insulating material from waste material, in particular from laminate waste and waste copper-clad base material for printed Circuits, according to the preamble of claim 1. It finds particular application in the production of laminates for the electrical industry.

The invention is based on a method described in DT-OS 23 43 345 for the recovery of metals and plastic materials from, being essentially about the preparation of the conductor material and the insulating plastic material the waste of electrical cables is for recycling in cable manufacture. For this purpose, this waste is shredded and ground into powdery granules, which due to the different weight of its particles by means of different Equipment and liquids, according to their proportions in different metals and thermoplastics is sorted and finally dried. That so reclaimed plastic material is sufficiently pure to be put in an extruder press can be used again without further treatment. This also shows Copper or aluminum after deposition of any content at Steel or iron parts are extremely pure by means of strong magnets and can also readily used for the production of new conductors or a melt of the metal concerned are added.

However, this method can be used for the reuse of laminate waste, which - apart from the copper of the lamination - are mainly made of resin-soaked Pass paper, do not apply; The reasons for this are on the one hand in the lower or entirely) Soh lacking metal content, which makes the separation by wet means with subsequent drying would become unprofitable, as well as in the difficulty of the after Sorting of recovered insulating material namely predominantly synthetic resin impregnated To prepare paper so that it can be reused for the manufacture of laminates can be.

Since, however, in the production and processing of laminates for the electrical industry a significant proportion of unclad waste, e.g. grinding dust Punching waste> trimming strips, pipe waste, cutting residues, etc., but also with the production of copper-clad laminates, for example as a base material For printed circuits, when they are cut to size, also trimmed strips and cuttings fall off, there is an urgent need for a method for their economical recovery and recycling in the manufacture of laminates.

The invention is based on the object of a method for recovery and recycling of laminate waste, which in addition to recovery of copper aucl.

the preparation of the insulating material, especially synthetic resin, for their use in laminate production, all the more so their cost-effectiveness to increase and avoid wasting raw materials. This task is carried out by solved the invention specified in claim 1.

Further advantageous embodiments of the method according to the invention result from claims 2 to 6, from which claim 2 is based preferred grain sizes for the preparation of the insulating material of the fine material or coarse material, claim 3 on the processing of the recovered metal parts, and claim 4 to further advantageous details of the preparation of the insulating material for its recycling.

Claims 5 and 6 relate to the metering method of the recovered insulation waste material or its share as a species-specific Filler in the impregnation resin solution used to impregnate the laminate paper webs.

The essence of the invention lies in the knowledge that for Recovery and recycling of the unavoidable in the manufacture of laminated peat A separation of the metal parts from the insulating material parts on dry waste Ways must be done if the latter are to be used again, as well as that the recycling of the insulating material is best when it is finely ground, with one Grain size of at most 50 / um takes place in the form of a viscous paste, which the Impregnating resin solution for the laminate production process is metered in and thus for this is recovered. For this purpose, the waste material is first known Way crushed and granulated and then from the dry mixed granules of Metal and insulating material particles make up a substantial proportion of the latter, which in the case of copper-clad waste, more than half the amount of the granulated waste material can be separated and collected as fine material by means of an air stream.

By subsequent sieving of the remaining coarse-granulate mixture the metal is separated from this and fed to further treatment while the fine and coarse material parts of the remaining insulating material-granulate mixture brought together, finely ground to a powder, and so in a liquid resin solution be dispersed. After all, it is processed for recycling in this way Insulating material as finely ground viscous paste of the impregnation resin solution for the Schtchtstoff- for example hard paperw production metered. It goes without saying that with RecSing, metal-free laminate waste proceed in the same way is, however, for the sorting out of the metal parts and their recycling Necessary measures are omitted and also the addition of a higher dose of the eventually paste added to the impregnating agent is possible.

The advantage of this new process lies in the fact that that in this way not only the metal but also the expensive insulating material can be supplied to the laminate production. Here the total amount such a quantity of the viscous paste is added to the impregnating resin solution, that the finely ground amount of waste io-40%, preferably 20033% of the weight of the corresponds to the amount of resin substance contained in the impregnation resin solution. Consequently but is about a quarter to one when manufacturing new laminates Third of the impregnation resin solution by recovering the insulating material the waste saved, which increases the profitability of the production of these Laminates increased very considerably.

These exist just like the base material for printed ones Circuits made of paper coasters soaked in a resin solution, which after they have been soaked or impregnation placed in several layers or layers on top of each other and under Heat application are pressed together, which belongs to the group of thermosetting plastics belonging resin hardened and layered with the initially serving as its carrier Paper forms what is known as hard paper, which ultimately also has one or both sides can be laminated with a thin copper foil, for example as a base material for printed Circuits Panels formed in this way, laminated or uncovered, must then cut to the final dimensions given differently in each case. Likewise, must also be made in a similar manner, for example in the form of a pipe or insulators assembled from plate sections to suit the purpose cut, drilled, milled, ground or treated in any other way to give shape be, whereby the variety of strip or piece-shaped as well as partially also results in powdery waste, the recycling of which is the aim of this invention is.

For this purpose, the material falling off in all these processes is used a coarse crusher such as roll crusher, hammer mill or the like and so by a cross-flow impact mill, cutting mill or another suitable one Granulator passed through it, with it down to a grain size of less than 700 / to be granulated. This granulate is first made into the fine material of insulating particles a grain size up to 300 / µm, e.g.

by air sifting or the like, separated and together with the coarse material of insulating material particles remaining after the metal has been separated finely ground a powder with a grain size of about 100 μm. This can be done using a Toothed disk or pin mill take place.

Finally, the previously finely ground and dispersed powder a grain size of about 100 / um with or better after its dispersion with the Resin solution, e.g. in a sand or bead mill or a corundum disk mill a grain size of at most 50 / um finely ground, which ultimately leads to a viscous paste is milled. The resulting viscous paste becomes the bulk of the impregnating resin solution in question, which may contain further additives such as Flame retardants, plasticizers, hardeners and accelerators may contain in the previously specified proportion added.

Contained in the collected, crushed and granulated waste Metal, such as, in particular, copper granules with a grain size of more than 400 μm immediately after granulation by preferably two-stage sieving of the remaining insulating peat particles separated, each fraction of the metal granulator freed from the remaining insulating material by subsequent air sifting will. These granules are then melted down, with any remaining insulation material or other impurities due to Pyro%: e are excreted or destroyed, and then its recycling, for example for the production of the laminating foils fed.

For a better understanding, the invention is explained below with reference to FIG Drawing explained in more detail, in which an embodiment of the process sequence is shown schematically.

Several tons of the initially described waste material 1 by means of a coarse shredder 7, 'e.g. a cutting mill, precut and then through a granulator 8 such as QuerstromprallmUhle or the like passed through, this up to one Grain size of about 650 / um was milled. Such a mill has been used for splitting off of copper has proven to be particularly advantageous, as it does so on impact in the cross-flow also granulated. The resulting powder was tn a pre-separator 9, e.g. wind sifting device, in set fine resp.

Coarse material parts 2 or 4 divided, with the solid material part 2 with a grain size of less than 300 μm consisted exclusively of insulating materials.

The subsequently remaining coarse material fraction 4 was then divided into several Sieving or air sifting processes according to the different weight in its Shares 6 of copper or the smaller and much lighter ones Proportions 2, namely of insulating materials, in particular phenolic paper powder 2, divided. A double sieve 10, for example a sieve machine with a fine material part, has been used for this purpose 11 proved to be particularly advantageous, which in its fine material part 11 the inflowing Coarse material 3 in a heavier fine material fraction 5 or 6 with a grain size of over or sorted out below 400 / um, while at the same time its coarse material is the coarse-grained one Material portion 4 with a grain size of more than 630 / um releases separately.

While the copper portion 6 after further air sifting in separately downstream coarse material or fine material separating devices 16 or 15 to remove phenol residues 2, which was fed to further metal processing, were the insulating material fine material fractions 2 of all separation and sieving processes are brought together and in a fine mill 17, e.g. Pin or toothed disc mill finely ground, finally in a dissolver or Mixer 18 dispersed with the resin solution and then in a fine mill 19, e.g. sand or pearl mill finely ground. The insulating resin solution dispersion 12 became a highly concentrated, preferably highly viscous, pumpable, stable paste 13 with no tendency to settle.

This paste 13 was finally an agitator tank 20 with impregnating resin solution 14 added as a cheap and non-alien filler for hard paper production, which resulted in a material saving of more than 20%. This is in view Considerable savings due to the large amount of waste of several 100 tons per year, which the comparatively low investment costs for the preparation of the Waste for its recovery and recycling is well justified.

Summary: The invention relates to a method for Back-threading of the unlaminated and copper-cased during manufacture and processing Laminates: incidental waste. The task is to reduce the consumption of raw materials and increase in profitability through the appropriate Processing of this waste for recycling in laminate production. The main solution is to separate the copper from the insulating materials after shredding and granulating the collected waste and subsequent melting the copper or finely grinding the insulating materials freed from the metal together with a resin solution to form a viscous paste, which is the impregnation solution for the coating is added. The invention is mainly used in the manufacture of Laminates in the form of hard paper insulating panels and bodies and of Base material for printed circuits.

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Claims (1)

Claims: 1. Process for the recovery of NEoMetall and Insulating material made from waste material5, in particular from laminate waste and waste copper-clad base material for printed circuits, the waste material crushed and granulated, then metal present due to its higher specificity Weight separated from the insulating materials, collected, cleaned and for recycling is melted down> while the insulating material is collected separately, if necessary sorted and recycled i c h n e t that from the dry mixed granulate of metal and insulating material particles A substantial proportion of the latter is cut off as fine material by means of an air stream and collected, and by subsequent sieving of the remaining coarse-granulate mixture the metal is separated from this and carried out for further treatment and that the fine and coarse insulating material particles brought together, pure to a powder ground, so dispersed in a liquid resin solution and finally as finest milled viscous paste added to the impregnation resin solution for the manufacture of hard paper will 2. The method according to claim 1, d a d u r c h g e k e n nz E i c h n e t that the waste material initially down to a grain size of less than 700 / µm granulated, of which the fine material of insulating material parts of one grain size deposited up to 300 / µm and together with that remaining after separation of the metal Coarse insulation particles to a powder with a grain size of about 100 μm finely ground and after or during its dispersion with the resin solution to a certain grain size of a maximum of 50 / µm is milled as pure. 3. The method according to claim 1 or 2, d a d u r c h g e -k e n n z e 1 c h n e t that by sieving the mixture of granulated waste material Separate metal granulate with a grain size of more than 400 / µm, sieved in two stages, each fraction by subsequent air sifting of the remaining insulating material freed and then melted down, with any remains of insulating material or other Impurities are eliminated or destroyed by pyrolysis. 4. The method according to any one of claims 1 to 3, d a d u r c h g e k e n n z e 1 c h n e t that the waste material before the fine and coarse insulating material particles by means of a roll crusher, a hammer mill or the like. crushed and so through a cross flow mill, cutting mill or a other granulator passed, and after bringing together by means of a Toothed disk or pin mill finely ground, then mixed with the resin solution, e.g. the solution of an optionally plasticized phenolic resin in conventional solvents such as methanol or a solution of an optionally halogenated epoxy resin in likewise common solvents such as acetone or methyl ethyl ketone, if appropriate with other additives such as flame retardants, pigments or other fillers, E.g. dispersed in a dissolver and finally in a sand or bead mill or a corundum disk mill is ground to a viscous paste. 5. The method according to claim 4, d a d u r c h g e k e n n -z e i c h n e t that the viscous paste of the main amount of the impregnating resin solution in question, possibly further additives such as flame retardants, plasticizers, hardeners and contains accelerator, is added. 6. The method according to any one of claims 1 to 5, d a d u r c h g e k It is noted that <let 'total amount of the impregnation resin solution is such Amount of the viscous paste is added that the finely ground AbEall amount 10-40 %, preferably 20-30% of the weight of that contained in the impregnation resin solution Corresponds to the amount of resin substance.