CA2196088A1 - Method of processing packaging - Google Patents

Abstract

A method is proposed of processing packaging containing reactive residues. The packaging (13) is fed into a cold zone (2), cooled to a temperature at which the residues contained therein solidify and then shredded while in that cooled state (4). The shredded packaging material (13) is then divided into one fraction containing the reactive residues and at least one other fraction; the fraction containing the reactive residues is fed into a mixing zone (6) into which simultaneously an agent capable of reacting with the residues is also introduced, with a catalyst if appropriate, and the temperature in the mixing zone (6) is maintained at a level below the softening temperature of the residues and of the reactive agent. The resulting mixture of residue-containing fraction, reactive agent and (where appropriate) catalyst is conveyed to a reaction zone (7) at a temperature sufficiently high to allow a reaction and is there allowed to react.

Description

21 9 6~88 f"
"_ METHOD OF PROCESSING PACKAGING

~his lnvention relates to a process for recycling pack-l~gs conLaining rea~tive resldues, ln pa~ticular cartridges for pro~ucln~ p~iyurethane fodm. In the process the packing ~ateria;s are reco~ered and the resid~es contai~ed therein con~erted into reusable products.
~ esidue-~ontaining packings as occur for ex~ple ir.
great ~uantitles in the form of wholly or partly empty car-tridges ~re increasing~y be~oming a di~posal problem. They cannot be dumped on disposal sites fo reasons of environ-ment~l protection since the residues containe~ therein can p~ss into the atmosphere, the s~il or the groundwater and lead to conside~ble damage there. The same holds for burn-lng, which is frequently incomplete in particular with chemi-cotechnical products and produces great quantities o~ pollut-an s which can be bound only ~y elaborate measures, if at all. ~urning thus leads to a great reduction ~ the volu~e of waste but does not necessarily so}ve the pollution problem.
Special problems ar.se when the residues ~ontai~ed ln the pack;ngs are ~hemselves reactive ~nd possibly ever. toxic products, as is tbe case for example with is~cyana~e-~ontaln-ing prepolymers for poly~rethane f~ams. The same holds for othex reactive plastic products, ror example self-c~r;ng c-hardenable mixtures for coatings, adhesive mixt~res, etc. Ir.
tne fol~owing the probiem will be dis~ussed in rela~lon to the disposal of prep~lymer-containing cartridges for pro~c-ing poly~rethane foams, this case being given on].y as an ex-ample.
Polyurethane foams ha~e become widely used in many fiel~s. They are commonLy used partic-~larly in the ~onstru~-tion lndustry ~or sealing and ins~llating, ~s well as in cther technical fields. Polyurethane ~oams are commcnly dlscharg~d ~rom cartridges containing a polyurethane prepolymer together with req~ired additives. The3e ~artridges cannot be reused.

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2 t 96088 ' _ - 2 -On the other han~, they are problem ~aste which cannot be disposed of in the nor~al way.
In accordance wlth effor~s to limit househol~ and indus-trial waste, measures are ~eing increasingly discussed an~
imple~ented to force manuf~cturers ~o take ~ack their produc~
packag~ng after use and ensure its r~use or disposal them-selves. Such measures have made it necess~ry to find ways of ~reating suçh waste econo~ically. The treat~ent of returned cartridges for polyurethane fo~m pro~uction involves a nu~be of pro~lems which ~o~npli~ate econlomic recyclln~. For exa.np~e, some returned cartridges can ~e under pressure due t~ the penetration of ~oleture during improper storage or t~eatme~, which makes both openin~ and ~urning a proble~. Fu~therm~re the cartri~ges have different fiiling co~dltio~s, ranging from over~ed cart~idges ~irtually full of prepolyme~ which can~ot 4e dischar~ed ~ue to a blocked ~alve, to ~irtually empty Gartridges with only a remainder of prepolymer adheriny to the e~ges in a~ uncrosslinked to crosslin~ed state.
~ p to now a number of proçesses have become ~own for recycling pa~ki~gs, includin~ aerosol ca~ for polyurethane foa~ pro~uc~ion. For example it has been proposed to pass pressure çans via a sluice system into a plant unde~ inert gas and crush them there. Furthe~, processes ha~e become known for passing aerosol cans into a plant, crushing them there and ext~actin~ the ingredients with sui~able solvents.
In ~hese proce~ses both the packing materials and the ingre-dients (prepolymer, propell~n~ ~re recovered.
~ owever these known processes, some of which are guite efficient and in use, are capable of ~eing i~proved with re-gard to industriai safety, process con~ol and effi~ien~y. It is problema~ic to separate the residues cont~ined in the packings in slmple fashion and direct the~, to suitable reuse.
Further proble~s arise fro~ the fact that the packings -on-tain toxi~ologic~lly unsafe substa~ces as well as combustible solven~s ~hich çan yield explosive gas mixtures after open-in~. ~n particular these process~s are designed fo~ recyclin~

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- _ 3 _ 2 1 9 6088 pr~pellan~-containing aerosol cans, however, which limi~s their appii~a~ility for pressureless cartridges.
The inventlon is therefvre based o~ the problem ~f pxo-vidir.g a process ~or recycling packings, ~or example con~a.n-ers holding polyurethane prepolymers in particular for foam prod~ction but also for adhesive purpcsesr together with sol-vents, and recovering the useful materials contained therein without releasing u~he~lthy and pollutive ln~redient~ in un-contr~lled fashion and withou~ the course of the pro~es~ ~e-ing burdened by reactive components released from the Pack-ing3. The proces~ shQui~ ~ee~ the re~uirement~ for industrial s~fet~ and i.n particular con~ert reacti~e resid~es ~til~ con-tained in ~he packings int~ a form suitable for direct fu~-ther proc~ssin~, This proble~ is solve~ according to the in~ention by a process of ~he ~bo~e~en~ioned type wherein the packings are introduced into a cold zone and ~ooled until resldues con-~ined therein solidify, the packings are then crushed in the cooled state, the crushed pacXings ~re divided in~o ~ frac-ti~n containing ~he reactive residues and a~ least one fur-ther fraction, the residue-containlng fr~tion is intro~uce~
into a mixing zone intc which an agent rea~tive ~ith the residues is simult~neously introduced, optionally together ~it~ a catalyst, the temper~ture in the mixing zone being held below the softenln~ temperatu~e of ~he residues and the reactive agent, and the resulting mixture of resi~ue-cont~in-ing f~action and reactive a~ent and optio~ally ~ta].ys~ is brought to a temperature s~fficient for reaC~iOn ~d rea~ted in a reaction zo~e.
The inventive process makes i~ pos$ible to open and proceqs p~ckings in ~ fully sa~e way. In particular lt per-mits ~he v~rious materials contained in the pa~ki~gs to be separ~ted safely. The re~ctivç residues, for exa~ple isocy-anate-cont~lning prepolymers in ~artridges for pro~ucing poly~reth~ne foam, ~re treate~ in a safe ~nner. Due to the freezing of the ingredient~ contained in the pa~kings there S0:31I35 069~65:N~ ~2bbS6 F2~2 6b+ 3HOd31N3~1 NN~WW3H:NOn OW ~~:2~ N~L-~2 _ - 4 -is neithe~ a reaction-i~du~e~ pxessure increase in the pro~-ess no~ u~desirable reaction be~wee~ reacti~e componen~s. A~
the temperatures prevailing in the prOCess ~he presenee of water is also harmless. The ~wo latter points are of impo~-tan~e in tre~ting isocya~ate-~on~aining products when for ex-ample damaged packings carry wate~ into ~he pr~ce~s. At the same time, re~ctive second çompo~ents ~ontained in ~o-calLed 2C fD~s, for example glycol~, carboxylic aci~S or water, can be easily intro~uced into the process. The inventl~e process is thus suitable for treating bo.th cartridges for lC and ~¢
foams and transltional forms b~tween the two simultaneously.
In the inven~ive pro~ess the pdckings, for example car-tridges, are fi~st introd~ce~ int~ a ~ld zone and c~oled thereln until the residues ~ontained therein, includin~ any low-boiling sol~ents therein, solidify. ~emperatures lowe~
than -~0~C to -1~0~C are generally suffiçient ~or this pur-pose, but one expediently works in llquid nitro~en as a cool-ing mediu~. In ~his ca~e it is import~t th~t the process be performed in the absence of oxygen to avoid condensation of llquid o~ygen which çould have an a~verse effect in later process steps.
The packings are expediently introduce~ into the cold ~one using a celiular wheel pneumatic sluice which introduces the p~cking lnto ~ g~ide cage extending in the coolin~ ~e-dium. ~n the ~old zone the p~cki~ ls then g~i~ed a suffl-cient distance through the cooling ~edi~m to ob~ain complete freezing.
When the desire~ temperature is reached, gener~lly the temper~t~re of liquid nitrogen, the packings are guided intc the c~ushing zone where they are ~ru~he~ in the col~ s~a~e.
The temperatures here should expediently be under -80~C to -100~~; it might ~e necessary to spray in liquid nit~ogen or cold gaseous nitrogen.
Cr~shinq lS exped~ently ~one in ~ hammer ~ill working ~g~inst a sifter. This ~hiev~s a shaking an~ fulllng effect which not only crushes to a ~esire~ particle size bu~ also 90:31I35 069~65:N~ ~2bbS6 ~2~2 6b+ 3HOd31N3~1 NN~W~3H:NOn OW b~:2~ N~r-~2 -- s --separates the various materials: metal, paper, plastic and ingre~i~nts. It has surprisingly turned out that the pa~king m~terials (metal, paper and plastic) can thereby be separ~ted extremely weli from the in~redlents ~reac'i~e resid~es an~
s~lvents/a~itivés in powder form), the ingredients being ob-tained as fine powde~.
In a subsequent sepAr~ting step the crushed packin~s are ~ivide~ into at ie~st two fractio~s, one of which contair.s the re~ctive resid~es includlng pro~ellant ln a solid ~a~.e.
This separ~ing step expedientiy u~es a sifter, prefera~ly a riddie sifter, thro~lgh whlch the fine components ~mainly re-actlve residues and solvent~ fall. Metal pa~ts ar~ separate~
with ~agnetlc methods, large plastic parts and scr~ps of pa-pe~ sieved out on the riddle sifter.
The frc~en ingredient~ from reactive ~esidues and sol-vent pass ~rom the separating zone intc a mixing zone into which an agent rea~tive with the residues is simultaneously introduGed. Temperatures l~wer ~han -~0~~ to -100~C also pre-vail in this mixing ~one to ens~re the frozen st~te of the i~troduced materials and solidify the spr~yed-in reactive age~t ~ne~iately int~ a fine pow~er. This permit~ fox~ation of a uniform ~ixture of ingredients ir powdex form an.d reac-ti~e agent, ~hi~h cannot ~eaçt due to the prevailing tempera-ture con~ltions. ~he temperatures in ~he mlxing zone are ir.
any ~a~e below ~he melting point of both the residues ~n~ the reactive agent.
A ~pray ~ower i~ expe~iently used a~ ~ mixing ~one, the fro~en ingredients falling in fro~ above. The rea~t.ive agent is sp~ayed into this pow~e~ st~eam from lateral nozzles, preferably together with ~old g~seo~s nitrogen to ensure the necessa~y low temperatures. It is expe.~ient to precool the re~ctive agent ~ut i~ must remain sprayable.
It can ~e expedient to spray in the reactive age~t ~o-gether wi~h a catalyst which promotes the ~eaction with the reactive re~idues ~f the packinss. This is gener~lly u~neces-s~ry with isocyanate-çontaining prepoly~er~, however, since ~Q:31I35 06~l16S:N~ ~2b~S6 ~2~2 6~+ lHOd31N3~1 NN~Wdd3H:NOh OW S~:21 N~L-~2 _ - 6 ~ 2~96088 the isocyanate-containing mixtures alrea~y ccntain such ca~a-lysts.
The powdery mix~ure of ingredients a~ reactive agerlt and optionally catalyst is ~hen ~ulded lnto a re~ctrion ~one which ~onsists for example of a conveyer bel~ movlng continu-ously under the mixin~ zone. ~he po~er colle~ting h~re is then ~rought ~o a temperature suffieient for re~ctio~ in or-der to react. Any solvents contained evaporate at this point ~nd are co~densed out at a suitable place, which i~ no prob-lem when nitr~en is used ~s a cooli~g medium. ~o give the rea~tion product the desired fo~m .he con~eyer belt can have lateral li~its. For separ~ting the reaction product ~rom the conveyer bel~ it is possible to pro~ide parting means, for example suita~le coatings or release paper. The he~t.ing in the reaction zone is expediently done with microwaves, which cause fast direct heating of the powder ~a~erial from the i~-slde to the outside s~ that uniform degassing occurs.
Following the re~ction zone one can provide further processing and treatin~ zcnes as well as a flnal sl~ice for passing out the reacted ma~erial, As mentioned ~ove, the inventive process is especially suitable for xecyciing resi~ue-contai~ing polyurethane fo~m ~artridges. In this case the reactive agent is in particular a hydroxy co~pound, for example water, ethylene glycol, pro-pyle~e glycol, glycerol, oligomers and mixtures thereof ~s well as ~e~ivatives thereof. Ethylene glyco~, water and poly-ether alcohols are preferre~, where~y ln any case ~t least two reactive hydro~en atoms should ~e present. Polycarboxylic aci~a c~n like~ise be uced. Espec~ally sultable polye~her ~1-cohols are ~he so-c~lled Jeffamines (tr~demark).
In recycling ~ackings for producin~ polyurethane foams it is advantageous to con~ert the isocy~na~e-cont~i~ing p~e-polymers in the process i~self i~to foam materials whiGh can be u~ed for example for insulati~g purposes. The inventive process can thus c~ntinuously produce insulation boards, whereby the propel'ants contained in t~e powder p~oduced in 00:31I35 069~6S:N~ ~2~bS6 ~2~2 6~+ 3HOd31N3~1 NN~Wdd3H:NOn OW 5~:2~ NYr-~2 the mlxing zone promote foam formation. It is also rea~ily possi~e to pro~uce foils or to admix additi~es, for example cellulose~containing materials, an~ then press these mixtllres into ~omposite mate~ials during or ~fter reac~ion. ~owever it is preferable to produce gran~les fxom ~e~cted material which are further processed later.
The inventi~e process is especially suita~le for ~ecy-cling pressureless polyurethane foam cartridges whi~h are empt.ed on site using a s~i~a~le pistol and then retllrned to the m~nufacturer for recycling, These ca~tri~ges, which are used both for lC and fo~ ~C foams, ~re pressureless ~urlng storage and generally contain no expa~ding or fo~ming agent.
I~ an lmprovement in fo~ing beha~ior is necessary and this improvement cannot be achieved by using w~ter a~ the se~ond compo~en$, low-boiling sol~ents c~n be present, for example pentane, w~lch are liquid ~t nor~al temperature but e~ap4rate with the seco~d ~omponent at the reaction temperatures of the prepolymer and produce arl expandin~ effect. The inventive process can likewise ~e used for ae~osol cans for polyure-thane foam production if an effective ~ep~tion ~f propel-lant is e~sured in the are~ of the reacti.on zone. The proces~
is thus fuhdamentally suitable for packings whlch also con-tain expanding agents and achieve ~n expanding a~d~or foaming effect, optionally in acoorda~ce with temperature.
The inventi~e proce~s will ~e explaine~ more closely ~y the enclose~ drawings, in which Fiq. 1 shows sçhematically an embodiment of ~ plan~ f-~r carrylng out the inventive pro~es~;
Fig. 2 shows the entrance area of the plant according to Fi~. l;
Fig. 3 shows the conveying, crushing and sor~ing part of the plant a~cording to Fig. l;
Fi~. 4 shows the mixing and reaction z~nes of the plant a~cordi~g to Fig. 1:
Fig. 5 ~hows details of the feed by the cellular wheel slui~ei 60:31I3S 069~6S:N~ ~2b~S6 ~2~2 6b+ 3HOd31N3~1 NN~W~3H:NO~'l OW S~:2~ N~r-~2 - ; ~ 2 ~ s6088 Fig. 6 sho~s details of the transport system gulde in a horizont~l projection, an~
Fi~. 7 shows the guide of Fig. 6 in ~ross section.
The view of an embodiment of the nventive recyçli~g plant sho~n in Figure 1 has entry sluice 1 which is fed car-trldges 13 to ~e treated via ~onveyor and sorting belt 11 ~Fig. 5). The entry sluice is preferably formed as a cellular wheel pneumatiç sl~ice into chambers l~ of which ~artri~ges 13 fall from a~ove via fee~ hopper l~ ~Fig. 2). Rotation of celluiar wheel 1 causes the cartridges ~o pass into the l~wer are~ of the s1uice and be ejected l~ter~lly with the he'p of gaseous nitrogen G~N from pipe lS. To make this possible ~he cel~ular wheel rotate.~ in a gas~ight con~alner ~pen at t~e top which ~an ~e sub~ected to pressurized ~seo~s ni~roge~
~AN from one side ln its lower ~rea ~o that c~rtridge 13 therein can be eje~ed o~ the opposite side into guide system 21. The nitrogen supply via pipe 15 ~.~ preferably ensured with gaseous nitrogen from co~d bath ~. O~viously the ~ota-tional speed of cellular wheel 1 ~nd the pressure surges f~om nitrogen pipe 15 ror ejecti~g the cartridges f~om the cellu-lar wheel are mutually coordinate~. The cellul~r wheel has for this purpo~e a measuring sensor ~rke~ M.
From the cellul~r wheel the ca~tridges p~s via guide 21 lnto cold ~ath 2 filled with liquid nitro~en. ~uide 21 expe-dien~ly consists o~ an elo~g~te b~sket construction open on all sides which per~its unhindered a~mission of liquid nltro-gen and es~ape of gaseous ~i~rogen. ~etails of guide 21 and tr~nsport de~ic~ ~3 for transporti~g çartridge~ 1~ will be described more closely below in c~nnection with Flgs. ~ and 5.
On their w~y through col~ bath 2, ~hi~h is s~pplied with fresh li~id nitro~en LIN in accord~nce wi~h level via. pipe 24 and has measuring sensor LIC for checking level, car-~ri~es 13 are coaled to the bath tempe~ature. The ca~e s'ructure of guide ~1 ensures free ad~ission of cooling me-~ium an~ quick discharge of prod~ced gaseous nitroge~. Gase-0~:31I3S 069~65:N~ ~2b~56 ~2~2 6b+ ~HOd31N3~1 NN~W~3H:NOn OW 9~:2~ N~r-~2 ous nitrogen is re~ove~ fro~ the ~a~h a~ea via pipe 1~ wi~h the help of ventilat~r 17. The len~th of guide Z1 and the transpor~ speed are ~d~usted so th~t cartridges 13 are cooled to a surflclerLtly low temper~ture of at lea~t -80~C to -100~~
even when comple~ely fille~ h re~ainder.
Cartridges 13 ~re transported in guide 21 with the help of transport device 23 expediently consis~i~g of circula~ing transport ~elt 25 with protrudin~ transp~rt forks 26 w~ich engage in guide 21 from above and push cartridges 13 gui~ed therein ahead of themselves~ Transport rolls 27 ensure pre-clse gui~ance o~ t~anspo~t forks 26. Fork~ 26 are disposed ~n transport belt 25 at inte~vals coor~in~ted with the size of çartri.dges 13 to be tr~nsported. Measuring unit M serves to monitor ~he tr~nsport speed and its co~rdina~ion with the feed rate of cartrldges ~3.
After running through co~d bath ~ cartridges 13 pass Ol~t of ~ e 21 into conveying devlce 3 (Fig. 3~ in the form of circulating conveyer belt 31 having transport segments coor-~ina~ed wi~h the size of cartri~ges 13~ ~onveying de~ice 3 is preferably formed as a ste~ conveyor whi~h ~eceives car-tridges 13 in the se~ments ~ormed by transport fork~ 33 dis-posed at regular inter~als and releases ~he~ o~erhe~d into crushing de~lce 4. The conveyer belt is guided vi~ rolls 32 provlded with ~easuri~g uni~ M fo~ monitoring a~d controll3.ng the co~veying speed.
Crushing device 4 ~onsi~ts of a shredder or prefçra~].y hammer mill 41. Ham~er ~ill 41 prefer~bly wo~ks against a sifter to guarantee a ~ertain particle si~e of ~he ~rushed m~terial. Sifter 42 simultaneously pro~uces a fulling effect which promotes separation of the insredients embri~tled by the cold from the container ma~erial. Obvio~sly one c~n add cooling me~i~m, p~e~erably liqui~ nltro~en ~IN, Vid pipe ~3 for ~alntaining the necess~ry low tempe~atures of -~0~C to -100~C if temperat~re check T~ indicates an inadmissible ri.se in temperature. The working spee~ ls checked and controlled 1~:31I3~ 06Yl~6S:N~ ~2bbS6 ~Z~2 6b+ 3HOd31N3~1 NN~ W 3H:NO~ OW ~~:Z~ N~r-~2 - lO- 2196088 vi~ measuring sensor M. Gageous ~i~rogen is remove~ via pipe 44 and recycled or blown off via valve 45.
From crushing ~evice 4 '~e cr~she~ ~a~erial passe~ into sorting deviee 5. This consists flrst of riddle sif~.er 51 on which coarse parts ~,re separ~ted from fine parts. Coarse parts are ~ainly the crushe~ materials o~ the container ~hi~h are shaken cff orl inçlined sifter S1 ~nd discharged frc~r~ the ~xocess via a sluice not shown.
Powdery i~gredients and fine p~rts of the ~ont~iner pass through riddle sifter 51 onto first magnetic separator 52 which sep~r~tes r~m2ining iro~ and alu~inum components fr~m plastic p~r~icles an~ ingredients. On first ~agneti~ s~p~r~-tor 5~ magnetic components are first separated ~nd fed to ~irst transport ~elt 53 whlch. also receives ~he metal ~r.d plasti~ parts shaken off by slf~er Sl. Second transpor~ belt 54 recei~e~ plastics, i~gredlents and nonmagnetic metal p~rts, ~hich are dlvi~ed into metallic ~nd nonmetallic frac-tion~ via second magnet1~ separator S5 couple~ with the transport belt. The metallic fractions p~s~ onto firs~ trans-port belt 53, the nonmetallic are guided dire~tly lnto spray ~o~er 6. Cold ~aseous nitrogen ca~ be supplied vla pipe 56 if ~emper~ture check TI~ ~ndicates an inadmissl~le rise ~n tem-perature. Measuring sensors M check the working speed of all moving parts of separating system 5. If the ~rtridges con-sist entirely of nonme~llic materials the ~agnetic separ~-tors can natu~ally be ~ispensed with.
Obviously a temperature of no more than -80~C to -10~~C
is e~sured both in the crus~ing plant and in the s~rting ~e-vice by suitable feeding pipes for ~o~ling medium, preferably ni.trogen in gaseous or li~id form.
~ he pow~ery ingredie~ts and pla~tic parts passing in~o spray tower 6 ~Fig. 4) and havin~ a te~pera~ure of no more than -80~C to -100~C sO that sol~ents contalned therein are also present in a solid s~a~e, a~e mixed with rea~ting me~ium and optionally cata.lyst sprayed into the upper area of spr~y tower 6 via feed ~1. The rea~:tin~ rnedium, preferzl~ly ethylene 2~:31I-5 069~6S:Ntl ~2bbS6 ~Z~2 6b+ ~HOdilN3~1 NN~Wdd3H:NO~I OW ~~:ZI N~r-~Z

_ glyo~l, is located in the liqui~ state in supply tank 62, the catalyst in supply t~nk 63. ~oth t~nks have mete~ing unit.Y
coordin~ted therewith.
Reacting medium from tank 62 and catalyst fro~ tank 63 are sprayed into spray tower 6 via pipe 61 in dosed relation to the reaçtive in~xedients, whereby a precovling stretch can be provided in the course o~ feeding pipe ~1 ~or cooling the materials to a bene~icial temperature ~above melting p~int).
However, the sp~ay material soli~ifie~ wit~lin the spray tower itsel~ at the temper~tures of less than -80~~ to -100~C pre-vailing there. For maintaining the temperature in the spray towe~ it is therefore expedient to introduce çooling me~ium a~itionally, ~or ex~mple l~qui~ nitrogen LIN ~la pipe ~4 or gaseous nitroqen via pipe 65, if temper~ture ~heck TIC in~i-oates a ~eed therefor. It is expedient to spray the coolir~
medium into the lower ~reas of the spray tower to en~ure ad-dj.t~onal swirlins and mixt~re of re~ctive compound, cat~lyst and reacti~e ca~ content by cold n~trOgen ~ising in spxay tower 6.
Fro~ spr~y tower 6 the mixt~re of reactive cartridge content, rea~tive compo~r.d and catalyst p~sses in pow~er form into reaction space 7. Wlthin reaction space 7 there is reac-~ion belt 71 for ~eçeivin~ the falling material from spr~y ~ower 6 and guiding it lnto actual rea~tion zone 72 where the reaction is induced by heat. For this pu~pose heat elements 73 ar~ disposed abo~e conveyer ~elt 71 for heating the reac-~ion material on ~onveyer belt 71 with microwaves or infr~re~
~ays to a temperatu~e sufficient fo~ reaction, for example room te~perature or thereabove.
To prevent reactlon materlal 74, i.e. the mixture of re-a~tlve cartridge ~ontent, re~ctive compound and cataly~t, from sticking to conveyer belt 71 it may ~e expedient to ~over the conveyer bel~ with separating foil 75 whlch is wound off roll 76a an~ onto second roll 76b. The separating ~oll lS optionally reusa~le~

~:31I35 06~1~65:N~ ~2bbS6 ~2~2 6b+ 3HOd31N~'dl NN~W~d3H:NOh O~l L~:21 N~r-L2 0~ conveyer ~elt 71 the reaction ma~eri~l reacts into the partic~lar produ~t desired. ~t the sa~e time solvent~ ancl adsorptively boun~ cooling medium nitrogen sti.il con~alned in the mixture fro~ the spray tower are released ~nd suoke~ off via pipe 77 a~d dlrected to sep~ration a~ solvent recovery ~ot shown~. ln the presence, or upon formation, of a f~aming agen~, suGh as pentane or CO2, the esc~pe from re~ction mat~-ri~l 74 causes parti~l foa~in~ of the rea~tion material, which is n~t un~esirable for certain p~rposes.
A~ ~he end of conveyer belt 71 there is scraper 73 for detaching the reacted r~action m~terial ~rom the convPyer belt or separating foil, it being p~sse~ out o~ the process via pro~uct sluice 8 ~d taken away ~ia conveyer ~elt ~1. Ni-trogen pipes ~1 and 82 regul~te t~e protective ga~ ~upply ir the sluice ~re~, ~he prote~ti~e gas used belng expediently nitrogen, which need not be ~ooled. Further nitroge~ pipes ~3 and ~4 in the are~ of the entrance and exit of separatil~g foil 75 prevent oxy~en from enterin~ the systèm in this area.
I~ is also unnecessary to use cool nitrogen here.
O~viously the inventive pro~ess is perfo~med in a cold-and heat-insulate~ plant. In particular the entranGe ~f oxy-gen m~st also be prevented in order ~o prevent li~uid oxygen from ~ondensi~g into cold ba~h 2. It is of adva~tage for the gas distribution to perform the entire process i~cludin~
spr~y tower ~ a~ temperatures at which solve~t and foaming agent exist in a solid state. This permit~ them to be remo~ed centrally vla suction pipe 77 in reaction space 7 and di-rected to recovery. ~he reacted~ure~ polyurethane materia]
emerging f~om the process in product sluice 8 can ~e ~irected to any deslred f~rther u~e in the form of granules Possib]e uses are for example ~or insul~ting materials and in compos-ite materials.
Flg. 5 shows details of the sluice system at the ~ntry o$ the process, the cellu~ar wheel pneumati~ slui~e bei~g re-tated ~0~ relative to the view of Fi~s. 1 and 2.

bl:31I35 0691~65:N~ ~Zbb56 ~2~2 6~+ ~HOd31N3~1 NN~W~3H:NO~ OW 8~:2~ N~r-~2 Car~ridges 13 wlth polyurethane prepolymer residues i~-tended for the proçess are int~uced vi~ co~veyor and sort-irg belt ll to ~e~l~ 12 of cellula~ wheel pneumatic sluice 1.
Feed hopper 14, under which the slulce rotates ~way, ens~res accurate introduction ~f c~rtrid~es 13.
Conveyor and sorting belt 11 expediently has ribs or forks 15 for separating cartridges i~ transported o~ ~he con-veyer belt from one ~nother. One can thus exaçtly coor~ina~
the cysle of cartridge rele~se with the transport speed of cellul~r wheel sluiee 1 and the transport cycle in g~lde ~1 of cold bath 2 at ~ given G~nveyin~ speed. ~he fixing of a cycle further allows c~rtridges 13 to be discharged ~ro~
sluice 1 in precisely timed fashion with the help of pressu~-i~ed ni~rogen through pipe 15 (Fig. 2j.
As e~ident from Fig. 5, pne~ma~c sl~ice 1 opens at its lower end ~opposit~ feed hopper 14) in~o g~i~e 21 into whi~h the car~ridges slide, being ejeçted toward tra~sport dev1~e 23 with the help of the pressure surge from pipe 15.
Figs. 6 and 7 show details of guide 21 and tr~sport de-vice 23 for transpor~in~ c~rtridges 13 within gulde 21.
Gui~e 21 has ~ltogethe~ an elongate, cage- or basketlike structure. Th~ guide consists s~bstantially of parallel ~uide rails Z2 which leave enough room there~etween for the a~mis-sion z~ liquid nitrogen ~nd the es~ape of evaporated nltro-gen. ~ulde rails 22 ~re held together ~y fixing ~ings ~7 on the outside such that their relative positlor. to ~ne other is fixed. The fixin~ rings encompass entire guide 21 with the ex~eption of the ~pper end, where the space hetween two guide rails 22 remains free so that tran~port fork 2~ or the like ~an engage from above and push c~rtri~ges 13 lo~ated i~ ~ui~e 21 through the gui~e. This re~lts ln the picture o~ an elon-gate cage comprisi~g parallel rails 22 ~n~ encompa~sing fix-ing ring~ 27 which leaves a free space over i~s entire leng~h in the up~er are~ for motio~ of transpor~ foxk 2~. The size of the c~e is ~oordinated with ~he size of the cartrldges and selected so that the cartridges cannot ~ilt when ~ei~g 5~:31I3S 069~165:N~ ~ZbbS6 ~2~Z 6b+ 3HOd31N3d1 NN~Wdd3H:NO~ OW ~~:Z~ N~r-~2 g~ided thro~gh. In the ~rawi~g cartridge 13 ls transporte~ ln the ~i~ection of the arrow with the botto~ fir.st and fork 2 embraces fitting 18.
Transport fo~ks 2~ are located on ~r~nsport ~elt 25 which transports the cartridges ~hrough ~uide ~l via a suita-bly dispose~ system of transport roll~ ~7 to con~eyer belt 31, where they ~ll out Or guide 21 an~ are recel~ed by transport ~lements 32 of conv~yer belt 31. Fro~ the end of ~uide 21 transport belt 25 is moved ~ack above bath 2 toward cellular wheel sluice 1, where forks 26 again eng~ge ln guide 21 a~ the intende~ place an~ transport the cartridges located in the guide through b~th Z. Ob~iously e~tire gui~e 21 ex-tends in the area of the a~t~al coollng stretch in cold ~ath 2 in such a way tha~ ~he car~ridges are washed by liq~id ni-trogen on all sides.

9~:31I35 069116S:N~ ~2b~56 ~2~2 6~+ 3HOd31N3~1 NNbWd~3H:NOh OW ~~:21 N~r-L2

Claims (16)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS.

1. A process for recycling packings containing reactive residues, characterized in that the packings are introduced into a cold zone and cooled until the residues contained therein solidify, the packings are then crushed in the cooled state, the crushed packings are divided into a fraction containing the reactive residues and at least one further fraction, the fraction containing reactive residues is introduced into a mixing zone into which an agent reactive with the residues is simultaneously introduced, optionally together with a catalyst, the temperature in the mixing zone being held below the softening temperature of the residues and the reactive agent, and the resulting mixture of fraction containing reactive residues and agent reactive therewith and optionally catalyst is brought to a temperature sufficient for reaction and reacted in a reaction zone.

2. The process of claim 1, characterized in that it is performed at a temperature < -80°C.

3. The process of claim 2, characterized in that the process is performed in the absence of oxygen.

4. The process of claim 3, characterized in that the packings are guided through a bath with liquid nitrogen.

5. The process of any of the above claims, characterized in that the packings are introduced into a cooling stretch with the help of a cellular wheel pneumatic sluice.

6, The process of any of the above claims, characterized in that the packings are crushed at a temperature < -80°C
with a hammer mill working against a sifter.

7. The process of any of the above claims, characterized in that the reactive residues contained in the packings are pulverized during crushing.

8. The process of any of the above claims, characterized in that the mixing zone is a spray tower.

3. The process of claim 8, characterized in that the reactive agent is sprayed into the powder of reactive residues passing through the spray tower.

10. The process of claim 8 or 9, characterized in that gaseous or liquid cold nitrogen is sprayed into the spray tower for temperature control.

11. The process of any of the above claims, characterized in that the reaction zone is heated with microwaves.

12. The process of any of the above claims, characterized in that gases released in the reaction zone are separated by condensation.

13. The process of any of the above claims, characterized in that the packings, cartridges and the reactive residues contained therein are prepolymers containing isocyanate groups for polyurethane foam production.

14. The process of claim 13, characterized in that the reactive agent is a hydroxy compound.

15. The process of claim 14, characterized in that the hydroxy compound is ethylene glycol or a polyether alcohol.

16. The process of any of the above claims, characterized in that additives are added in the mixing and/or reaction zones.