Note: Descriptions are shown in the official language in which they were submitted.
1 ``` 2134117
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",1 40
,;," ~ ~ W093~22077 PCT/EP93/00988
"Method ~or proces~ing residue-containing packages"
D~scription
This inventiGn conce~ns a method for processing used or damaged,
~'i3; ~ residue-¢ontaining packages and recovering the valuable
~at'erials, in parti~cular rom pressuri~ed cans (aerosol cans) for
dis,pensi~ng polyuret~ane foam with propellant gases, by e~tracting
:them with~a;sol~ent, as:well as a plant for using this method.
,~,, ~ ~
Residué-containing packages such as partially or completely
emptied aerosol~cans, which occur in great quantities, are an
'~ ; increasi~ng:~problem:f~r~waste disposal. They cannot be dumped in
.. ,~ wa~st~e disposal~site~s ior environmental~reasons becau~e the
~i "~ r~e~s~idues;~sti~ contained;ln the cans can escape to the
atmos~pher:e,~the ground, or:the~ground water where they can cause
`~ ,cons:idera~bl~damage. 'The same~appiies to incineration which is :
xe~uently~not:complete:,;particularly for chemi~al-technical
~ ;products,~:and~which:~:p'roduces great quantiti~s of harmful
:, ~ s~ubstances~whi~ch~aan only~be bonded,: if at all, through very
expen~ive~mea~res:. ;~ n.~ofar, incineration will greatly redu~e
.i ~ t~e~waste~:~volume~,~but does not~lead to a ~olution of the ef~ects
on the~ ~enYironme~t ~
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93/22077 PCT/~P93~0098
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In the following, we will discuss this problem in detail by
referrin~ to tha disposal of prepolymer-containing aerosol cans
for producing the polyurethane foams.
The polyurethane foams have found a wide use in many areas. In
the co~struction industry, i~ particular, they are used for
seali~g and insulating, but also in technical areas. As a rule,
p~lyur~thane~foams are dispensed from aerosol cans ~ontaining a
polyurethane~prepolymer together wlth the necessary propellant
a~d,~if~ne~essary,:s:ome additives. These aerosol cans are
pr~ssurized, cannot be reused and must therefore ba disposed of.
`On the other hand,'they represent a problem which cannot be ~
sol~ved through normal:~waste disposal. In addition, aerosol cans,
particu~larly~older~one~s:, regularly contain f1uoridated
hydrocarbons,~:whl~h~are~considered damaging to the ozone layer
a~d~should~ther~fore no~t reach the atmosphere.
Wi~thin~the~f~ramewor~of the efforts~to contain r~sidential and
commerc~lal waste~ creaslngly measures arS discussed and
egulatio~s~p~ssed,~ whicb:force manu~acturers to take back ~hese
produ~t~ a:f:ter;~se:;and~take~meas~res~for their reuse or disposal.
Thés~e~'measures~ha~e~made~it~ neaessary~ earch for ways to tr~at
s~h~::waste,;~p:roduc~s~in~;:an econo~ic way.
When~pro~èsslng~thes~e returned~aerosol ca~s for polyurethan~
f~o~m6, ~:number~0~ problem~:~a~i~e~which; until now, have been
~ ~, .~
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W0 93~22077 PCT~EP93/00988
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an obstacle to an economic recycling and recovery. Some of the
returned cans, for e~ample, are still under considerable pressure
hecause of the r~mainin~ propellant gas, which cause3 problems
wh~n shre~ding them or incinerating them. Furthermore, these
cans are at d~ferent levels of filling~ rangin~ from outdated
cans with practically full prepolymer content, which cannot be
disp~nsed because of ~ blocked valve, to the practically emptied
cans with prepolymer residues sticking to the edges, either in
interlaced or non-interlaced condition. Until now, these varied
conditions stood in the way of a unified method for recovering
the residues.
U~til now, aerosol cans were processed in plants filled with
tr~ditional inert gases because of the assumed danger of
explosion during the process. The term "inert" here means non-
c~ombustible. Such inert gases include nitrogen and argon.
Ho~ever, e~periments showed that the use of nitro~en inflates the
gas balance enormously and has a ~egatlve ~nfluence on the
eff:icient separation of propellant gas residues. In par~icular,
the presence:of large amounts of nitrogen r~quires very powerful
a~d thus also very;expensive condensing plants to achieve a
ufficie~t s~paratio~. On the other hand, using inert gases to
avoid~an explosion;in the plant is necessary.
Thus, the invention is ba~ed on the task of producing a method
for processing packaging materials, containing polyur~thane
prepolymers for the fo~m production, but also for adhesives
" ~
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W0 93/22077PCT/EP93joo988
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so that the valuabl~e materials contained therein can be recovered
; ~ without releasi~g conten~t materials that damage health and
environment and~without stre~sing the proce~sing cycle with large
~4 ~ amounts of fed-in nitrogen ~ At the same time, the ~etho~ is
'~ int,ended t~o meet the~r~equirement~ ~for~protection against the
`,dang~er~of~exp~losi~on~
The~lnven;tion~so;lv ~t~h~s~peoblem~with~a method as described in
the~beginning which~i`s,~carri~ed out essentially in an atmosphere
,,'~ o ~pEopel;lant~g~s~andil~or~'s`;olvent vàpors Preferably, this is a
met~hod~which includes~the f~ol~low~ing~parallel steps
'"~ Fe~e;dIn'g~the packag`ing~matèri~als~ into~a~working container whi'le~ '
at~,the~same~time,~shredd~Lng~'~them;ànd~then extracting the residues
'~ t ~ s~o~l~v~en~t,~
~idue containing solution from thé working
j,",~ ~ rat1,ng~the~re~ldue-conta'i~nlng~solution in this
1 ~ n~c ~ a~1ner~by~disti~ ing out ~the solvent, condensing
returning;the solvent to~the working
~ n~ 'ng,,~resl~dùes ~rom~the~ w~orking container~and,
o;l,lo~w,lng~u~'f~icien't~en~richme~nt,~ recovery of these residues in
t ~ ~ troT~be~di~ i~ll tion container
,~ r~e~ers~to~gases~used~as~propellants-~`and foaming agent in
t'radi`tional~~pressurized~cans~ /ae~rosol~cans)~ particularly th~se' ''
'~for~p;roduaing~polyurethane ::f:o~am~as:~p ropell ant and~: foaming agent
~ tic ~ ,~,this~inc`ludè's~propane,~butane, dimethylether,
uorocarbons~ a~'we~ as,~fl~oromethane and fluoroethane
,;`~approximate'ly~R~134a~and~R~152~a)~ às well as
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WO 93/22077 PCT/RP93/00988
fluoridated chlorinated hydrocarbons, as far as these are still
in use and licensed for use, C02, N20 etc. Nitrogen and argon
are included only in that they are released from pre3surized cans
were they form a component of the propella~t mixture contents.
"Pxopellant ~ases'~ in the narrow sense tha~ they used in the
invention ref~r to the propella~t gas~s released from pressurized
cans that are processed. It must be understood here that in the
starting phase ~or the method, "propellant gases" from other
sources must~be used to mak~ the plant inert. R 134a and Rl52a
a~e par~icularly suited for ~his~ The extraction solvent, which
is present in the atmosphere based on its vapor pressure, also
plays a more or les~ significant role in rendering the plant
inert. up to 50% of C02can be added to this mi~ture to protect
against the dang~r of ~xplosion.
e~ have to point out here that the operational safety of th~
method depends on ~the act that: the process takes place in a
c losed: system and above the explosiotl limit of all component
materials that are combustible and explosiva. Insofar, it doe~
not r~st on the compl~te replacernent sf oxygen by a non-
cornbust1bl ~ gas .
T~e~packaging to be processed is~preferably transf~rred via
conduit into ~he working container. This ca~ be done with a
tradi~tional co~duit~ which ensure~ that the container remains
sealed against the environment.
If the pacl~agillg material ha~ not ~een oper~ed, it i~; useful to do
this ~ durlng the feed-in and preferably along with
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WO 93/22077 PCT/EP93/00988
-6-
the shredding, e.g. in a shredder especially designed for this
purpose. In the following, this is called shredding.
It is particularly advantageous to open or shred the packaging
materials~by sprayi~g them with solv~nts. On the one hand, this
prevents ~oaming and, on the other, possibly entered water is
absorbed by the solvent~and d-istributed before it causes
uncontrolled reactio~s with the content materials. This is very
important parti;cularly with materials that are sensitive to
mQisture:,: esp~ecially moisture-based interlacing of polyurethans
prepolymers.
The shr~edded packaging material is subsequently placed onto a
conv:eyor~in the work area, preferably a worm conveyor, which is
sui~ted~ for separa~ing the solid materials from fluids and
solvents.~ A~magnetic~conveyor:system must be considered if these
packaging~mat~erials are:ferromag~etic. A combi-nation of both
conYeying meth~:ds may~also be use~u~l, particularly if the
pa~c~aging-materials consist of tinpla~e wit~ plastic cQmponents,
hich ls~oftèn the~ca~e with aerosol cans.~
E~traction~of~the~residues from the opened and/or shredded
ackaglng material :ta}ces place in~the working container with a
sol:~rent that ~is spe~ifically designed ~or the respectiYe residue.
In ;~ny~case, ~suitable solvents~ a~re those used to produce the
packaglng con~tent: originally and/or those still ~ontained in the
packaging materia1s.
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~O 93/22077 PCT/~P93/00g88
On the one h~nd, extraction may take place by dropping the opened
and/or shredded packaging materials into a working container
~: filled with solvent and:leavlng them there for a period before
they are moved along. The parallel alternative is to spray the
packaging materials during the shredding and/or the conveying
proceA~s with fres~h solvent and then washing them. It is useful
to bring the packa~lng materials in all three stages in contact
wi~h the solvent, that is to spray them during the shredding and
conveyi~ng as well as subjecting~them to solvent in the working
container, for exa~ple in a catch funnel for the worm conveyor.
Subsequent to removing them, the solid residues are then dried in
a~y:optional sequence,~are brought out on the conveyor and then
~ sorted and:mo~ed toward the recycling area.
.~.".~
The traditiona1 est~rs, ketones, aliphatic and aromatic
:hydrocarbons~and their derivatives are particularly well suited
a~ solvents,~ especially those with a boili~g point of about
200~C. :If containers with polyurethane prepolymers are
~ p:~ocessed, then:acetone and toluol are particularly well suited
v~ ~ as so:lvents;.
:Large amounts of propellant gases are released during the
proc~sqing o~ residue-containing sprayr pressuri~ed and aerosol
cans. ~It~is~not desirable that these gases escapa to the
atmosphere. If these propellant gases are not needed as inert
ii; gases,~they are collected and condensed with suitable means.
Such~a condensation on the one hand may take place through
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WO 93/22077 PCT/EP93/00988
compression until the gas li~uefies and on the other by
condensing out under low temp ratures. These ~easures are
use~ul, particu1arly ~or propellant gases that can be liguefi~d
such as low boiling point fluorocarbons or e~en combustible
hydrocarbons such as propane or butane.
The inv~ntion method transfers the residue~containing solution in
:the working containe~r to a distillation container with, fsr
example, a pump. In the~distillation ~ontainer, the solution is
further condensed. To do this, the solution is heated up and the
solvent distilled out of the liquid phase. It may b~ useful to
work with reduced pressure to reduce the boiling temperature and
avoid displaGements in the residues. The distilled out solvents
are~condensed and, following this cleaning through distillation,
a:re returned to the processing cycle if ne~essary. The residues
in~the distil:lation container liquid are drawn off after they are
su~i~cientl:y condensed:and removed for further processing.
In case the~method in this inYention is used to process aerosol
ca~s with polyurethane:prepolymers,~ it is useful to add ~ known
th:inner to increase the flow capacity of the prepolymers that
collect in the distlllation container. Such a thinner should
have a higher boiling point th~n the respectively used solvent.
Parti:cularly-suited for this is trlethylphosphate or fresh raw
material s~ch as the raw materia1s used originally to fill the
packaging l material~ . ',
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WO 93/2~077 PCT/EPg3/00988
9 _
The invention method is carried out with protective gas.
Protective gases are the previously listed "propellant gases" and
C02~ C02-containing combustion gases and others like it, whereby
the displacement of o~ygen i~ the processing range is
particularly important to avoid an explosive mixture. If a
stored propel lant gas admixture such as C02, R 134a and R 152a is
used, it is useful to circulate it, whereby at suitable stages,
propellants that are released from: pressurized cans and
eYaporated solvents are separated out.
Or~e special advantage of the inventive method that it can b-~ run
continuously and, with slight modifications, can be adapted to a
multitude of pressurized canlaerosol c:ans now on the market.
:: :
Thus, ;the inventive method~ makes ls possible, for example, to
process residues-containing polyurethane prepolymers from aerosol
cans and other containers and recover these so that they can be
reused while, at the same time, recovering the raw material for
the containers in a r~latively clean form so th t they can be
re~c:ycl ed or sent to a waste dump . The prepol ymer, which i~
~ énriched~ and concentrated during the~ proces in the di~tillation
`~ ontainer can b~ used for many purposes. For instance, it can be
used as adhesiv.e, dissolved in toluol or another solvent, or as
bonding~ag~nt for composite materials gr as coupling agent for
;~ :the;:produc;tion of molded parts made from reeYcled products such a
~ vinyl:tiles made of granulated~old tires.
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~ WO 93f22077PCT/~P~3/00988
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In the course of this m~thod, the residues from aerosol cans or
. contai~ers are moved to the working container and submerged in
'ii!`. ~ th~ solvent therein. As a result of the feeding in of residues
: lnto the workin~ container and return ~f distilled solvent, the
volume inside the conta1ner rises above the operating volume
: during which solvent is moved from th~ working container to the
distil lation cos~tainer . On the whole, there is a constant volume
of solvents and dissolved residues in the working container~
~ i
With a suitable medium, the distillation container is heated
until the solution inside is boiling and a continuous solvent is
distilled out. This solvent is then condensed with a cooling
agent and returned directly or indirectly to the working
container so that this container always has ~resh solvent for
dissolving the residues that are conveyed in. In this way, the
residues that en~er the working container are extracted
continuously with 5QlVe~t. The extracts become concentrated in
the distil-l:ation container b~cause ~he solvent there is removed
continuously and will be recovered from there once they are
concentrated enough ~ Insolubl e residu~s that remain in the
work:ing contain~r are drawn off from th~re at certain intervals.
The us~ of the inve~tive metho~ is particularly advanta~eous for
the recovery of prepolymers from aerosol cans for the production
of polyurethane foam. The aerosol can empties via an adapter
into the working contalner. However, it is more advantageous to
.open ~he cans and extract the contents in the working container.
It is preferable to shred the aerosol can inside
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i 213411~
WO 93~22077 PCT/EP93/00988
the working container in a specially equipped device, such as a
~shredder. The shredding residues can be removed fro~ the working
container with a magnet because aerosol cans usually consist of
tinplate, or with a worm conveyor, as mentioned above.
~Ester, ketone, apliphatic or aromatic hydrocarbons or their
derivatives with a ~o1ling point of about 200 C are particularly
~: :: sùited as solvent for the extraction. Alkyl ester of
monocarboxylic acids and ketones with up to 8 carbon atoms, as
well as alkyl benzene~with up to 10 carbon atoms are especially
~:: suitable. Acetone, ketone, toluol and xylene are preferred. If
the extracted prepolymer subseque~tly is to be used for
adhesives, it i~ aduisable to use toluol because adhesi~es based
n~polyurethane are frequently u~ed in toluol solution. In
addition, solv~nts of polyurethane prepolymers in toluol have a
comparably low viscosity.
A:t:hinner may be added to the dlstîllation container which
ensures or improYes the ~low~bility of the ~ransferred and
concentrated prepolymer. If the thinner is added at the start o~
;~ he e~traction already, it must have a higher boiling point than
:the solvent so that it~does not become depleted during the
:è~traatio~. Ge~erally ussd thinners for prepolymers are
rialkylphosphate, particul arly trlethylphosphate, or other raw
materials ~hat:~:correspond to:the original material.
. ;~
, ~
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W0 93/22077PCT/EP93/00988
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: With the inventive method, the propellant still contained in the
aerosol cans - as ~ rule fluoridated chlorhydrocarbons, partially
halogenated hydrocarbons, dimethylether, propane, butane, etc. -
is collec~ed and recovered if it is not used to render the plant
inert. For th~s ~urpose, the gas flow coming from the worklng
container can be condensed so that the propellants in it are
liquefied. A~ an alternative, the propellants can be condensed
b~ cooling them and collected in a cooling trap.
: :
~:~ The inve~tive method is suited for batch quantities as ~ell as
for a continuous process. However, a continuous operation is
recommended because of the still high investment costs.
1~ :
Furthermore, the invention cor.cerns a plant for use with the
~:~ inventive method. 5uch a plant includes an incoming conduit, a
de~ice for opening tha fed-in packaging materials, a collection
container ~or the opened materials, at least one each feed-line
: for fresh solvent and protective gas, one discharge for solvent
co~taining soluble packaging residues, one~conveyor for solid
packaging~residues as well as at least one solvent spraying
nozzle that is directed toward the device for opening th~
~;~ pac~agi~g materials~ Peripheral equipment for recovering the
solid and dissolved packaging residues, recovering the solvent as
well as a trap ~or propellant gases released from the packa~ing
materials are also connected
~: ~
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~: NO 93~22077PCT113P~3/00988
-13-
:The device for opening the fed-in packaging materials, which is
~: used in the plant, consists of a traditional ~shredder with two
~: counter-rotating dr~ms equipped with cutting blades. It is
~t`~ essential that such a shredder or any other device for opening
the packaging materials is sprayed with solvent during the
,!"~: proce~s of opening so that all released residues are absorbed
directly in by the solvent. This avoids a foaming up of the
conten:ts if it con~ains propellants,~ but also the sticking
to~e~her. At the same tlm~, any water adheri~g to or which has
e~tered the packaging material is distributed by the spraying so
~: that an uncontrolled reaction between the water and any released
~packaging content is avoided. This is particu~arly important
~ during the~pro es~ing of packaging materials containing
;i ~ :polyuretha~e prepol~ymer, which interlaces uncontrollably if there
t`~ ~ i s water presen~ and can gum up the opening device. In the
presence of~ sufficient~ amounts of solvent~ thP concentration o~
water~that~has~entered ca~ be reduced to a level where an
un~co~troll:ed reaction is impossible. Any interlacing that might
still occur wi}l~sta~y in the tolerable range.
t~is useful to;h~ve at least one spraying no~zle above the
shr:edder.~ t is particularly advantageous if during the process
,`~n~'l ~ Of~ opening the contalners, the ope~e~ is sprayed with solvent
~ ~ f~rom ~;top~ and bottom: with at leas:t one spray nozzle. Following
.~, ~ the~:shredding,:~the packaging materials, together with the
i~ ~ sprayed-on solvent, are transferred to a collection and
.! ~ e~trac~ion contai~ner from which the dissolved and/or liquid
~ components ar~ discharged
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WO 93/22077 PCT/~P93~00988
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~ia a line a~d the solid re~idue~ are removed by conveyor.
It is useful if the conveyor is a worm conveyor which projects
into the lower part of the collection container filled with
solvent and removes the solid co~ponents from there~ This ~orm
conveyor is preferably sprayed with fresh solvent from one or
more spray noz~les to wash off any packaging residue solution
still clinging to the solid packaging residue that is removed.
Th~ washed conveyor ~aterials is then moved through a drying
pLant and removed via an outgoi~g ~onduit from the plant.
Subs~quently it i5 moved to ~nother place for further sorting and
reuse.
Th~ solvent used in the inventive method is effectiYely
recirculated. This requir~s a ~ontinuou~ removal o~ the solvent
from the ~xtraction and coll~ction container, distilling out of
the dissolv~d content materials and, following condensa~ion,
feeding the solvent ~ack into the plant via a pipe s~stem and the
spray ~ozzles or, i~ ne~essary, the washing de~ice.
In accordance ~it~ the inventive method, the plant is run with
protective ~as, as described abo~e, If'the protective gas i~ not
released from the pac~aging materials themselves, it is piped in
n~ear th~ opening device and is drawn off again from the
ext~actio~ and working container and/or th~ dryiny plant. In
order to a~oid add~tional costs, the protective gas can be
recircul~ted. It is usefu1 in that cas~ to e~uip the protective
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15-
gas circulation wi~h a device to separate out aerosols, moisture,
: propellant gases that were carried along and absorbed solvents.
It is useful to load the conduits with inert gases via separate
lines. T~is lS the only time it makes sense to use nitrogen,
ar~on or C02 to prevent unwanted gases f rom escaping to the
nvironment.
Th~ inventio~ is explained in more detail in the enclosed
drawings (preferred form), which show as follows:
~5 ~ FLg. ~1 A laboratory-type recycl~ing pla~t for illustration.
:Fig. 2 A technicaI plant according to the invention.
Fig. 3 A detailed representati~on of the plant in FigO 1.
Figur~e 1 shows a labQratory-scale recycling plant for
polyurethane foaming agent. Inside a three-necked flask 1 with
feed-in 2 and an overflow 4, as~well as a vertical tube which
ends in a reflux condenser 3~ is the e~traction solvent, to which
::the contents:of not completely empty aerosol cans for the PU foam
prod,lction :is a:dded ~ia a f eed-in 2 and an adapter tha~ is not
shown. A hollow magnet 10, which is moved with a magnetic
, ~ stirrer 9, ensures continuous mi~in~.
The solution frorn fl:ask 10 is transferre~ to liquid flask 6 via
overflow 4 in l:h~: same amounts at whi h material is added via
fe~d-in 2: to the three-necked fl~sk. A shut-off val~e 5 ensures
il ' ~
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W0 93/22077 PCT/EP93~00988
-16-
that there is a continuous ~upply o~ solution. The liquid flask
6 is heated with a heated ~th 7 until the solution inside is
boiling and evaporated soivent is distilled out via a tube 8
which connects to the reflux cooler 3. The solvent without
extract that condenses at reflux coc,ler 3 drips back into
operating flask 1, where it again participates in the extraction
and,~at the same time, effects a transfer o~ solution to the
liquid flask 6.
The wo~king:o~ the~inventive~method in the ~bove-described
a~paratus starts with the preparation of operating flask 1 which
is filled, ~or e~ample, with acetone as solvent. Parallel to
that, a small ~mount o~ thinner such a triethylphosphate is
fill~ed;into liquid ~lask 6 along with another solvent 50 that the
colleGtlng prepolyme~ in it remains free-flowing.
Subseguently, the cycle is started. The liquid fl~sk 6 is heated
to about 90 C and ~Xe reflu~:cooler and magnetic stirrer are
activate~ After about 15 min., a system cycle ha~ balanced out,
mea~ing as~much sol`vent as evaporates from liquid flask 6 via the
disti~llati~on bridge 8 into reflux ~ooler 3, condensates ther~ and
drips~into operating;~fla~sk I. From there, the solvent circulates
:via~over~low 4 and shut-off ~alve 5 bac~ to liquid flask 6. The
crcl~e IS~ c:loeed. ~:
As~soon;as a~baIance has been established, PU foam is fed into
operatin~ fla~k 1 via th~ feed-i~ tube 2 and a~ adapter which is
not depiated. There,:the foam dissolves immediately, the
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: W0 93/22077 PCT/EP93/00988
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~prepolymer dissolves and the propellant escapes through cooler 3
and is deposited in a cooling trap (not shown~ at its upper ~nd.
~' The fed-in prepolymer ~olume flows as a thinned solution via the
~ ov~rflow 4 into liquid flask 6. There, the prepolymer is
I ~: enriched to the same degree that PU foam is sprayed via feed-in
I
tube 2 into the operating flask 1 and is then transferred wo the
iquid fla~k as a thinned solution. The free-flowing solvent, on
the other~hand, is in the cycle and is returned again and again
`from the:~liquid~flask to the operating flask.
A~ the~end o the operating:cycle, a prepolymer solvent mixture
rich in prepolymer forms in llquid flask 6. Closing the shut-off
valve will prevent new solution ~rom ~lowing into the liquid
flask:so that th~ prepolymer can be condensed further through
distillation. The prepolymer is drawn from the liquid flask once
it:~has~reached the desired concentratlon and/or enrichment.
It is~natural that not: only the prepoly~er component ~rom the
a:e:rosol~cans will be enriched in ~he liquid flask, but also the
inherent addi~tives and:catalysts. As far as the product is again
used~to~:form:~polyurethane, these~substances do not cause any
probl;ems.~ f it~ is used for~'other purposes, these substances can
be~:remov~d~at least partially through distillation under normal
pressure~or~in~:a va~cuum~through extraction with:solvents, which
~ ~do.~not dl~solve~the:~polymer and do~not react with it.
~ ~ .
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~igure 2 shows a dlagram of ~hs processing sequence inside a
;~; plant for prepolymer recovery from packa~ing containing
prepolymers, particularly aero~ol cans, which i~ operated
according to the inventive method. This method can be used to
1 process other packaging materials as well, without modifications
apparent to the e~pert.
,:~
The plant as shown in Figure~2 consists of three stages, the
mechanical processi~g, the prepolymer recovery and the propellant
r~covery. In the mechanical processing stage, ~he delivered
packaging materials first pass through an initial storage area
and then reach a charging station where the packaging is freed of
foreign materials and plastic components and is also pre-dried.
They are then fed into a shredder l2 via a metered addition with
a scale and an input conduit 11. In the shredder, they are
shredded while being ~prayed with solvent and transferred to
: working container 13. In this working ~ontainer, the shredded
packa~ing mate~ials are washed with solvent and separated from
ny soluble components. Th-e solid -omponents are removed via a
conYeyor 14: ~hile ~ing sprayed continuously with solvent and are
then:fed into ~dryi~g plant 15 and subsequently removed from the
operating ~ycle via~a conduit 16. The solvent evaporated in the
drying plant lS is cond~nsed and re~urned to the process. After
b~ing removed, the shredded solid ma~erials are sorted according
:to,material type and moved to a recycling facility.
.iJ ~ The solvënt collei~e~ in worki~g container 13 and all residues
J~ ~ di~solv~d ~herein is conducted through line 17 to a receiving
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~: c~ntainer 18 from which the solution is then piped to the
distillat.ion plant. There, the solution is distilled out, if
~ necessary under low pressure. The distillation residue is then
,1 drawn off, adjusted and conditioned for furt~er use and returned
to the economi.c cycle. Residues which cannot be reused can
either ~e burned or deposited as concentrate on a disposal site.
The solvent distilled out of distillation plant 19 is condensed
;~ .
in a ondensation plant 20 and r~turned to the cycle via a
s~orage tank 21 and line 22. Solvent losses are balanced by
fresh solvent. The condensed solvent travels from storage tan~
21 ~ia ~pray nozzles (see Fig. 3) to shredder 12 and conveyo:r 14
back into working container 13.
L~ike the; extraction and distillation, the shredding inside
shredder 12 is done in the presence of protective gas, piped in
via line 24. Normally, the accumulating propellant gases are
su$fici~nt ~to cov~r the protective gas naed during the plant
operation. ~A ~ePd-in~via ~ine 24 is needed, in particular, if
:mo~st:ly empty~pres~urized:cans are process~d or if the plant is
star`te~. ~he ga~ component released duriny shreddi~g i~ led
tog~ther:with the protective gas flow via line 25 and, if
appl~icable,~:~an aeroaol~separation plant and drying plant 25a to a
aondensation faci:li~y 26.~ There, in a first ~tage 26a, adherin~
olvent~ is ~ sep~rated out and fed :into a storage container ~7
which is connected:via line 28 with the solvent tan~ ~1 for
condensing plant~ 20.~ ~ln ~ second stage 26b, the propellants
: ~
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~0 93/22077PCT/EP93/00988
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are conden~ed, recovered and collected in a tank 29 if they are
not used ~s prote~tive gas for the plant. Propellant gases which
are collectin~ in distillation plant 19 can also be fed into the
propeilant condensing plant. A portion of the propellant gases
is returned from the condensing plant to the processing plant
~, ~
nd, if necessary, replenished from storage tank 35 via line 24.
3: Conduits 11 and 1~ each are supplied via lines 32 and 34 with
nitrogen from liquid gas tank 30, whi~h arrives either after
~ ~ passing through a distiller 31 or heat exchanger 26b.
3; It is useful to condensate the propellants from line 25 in
condenser 26b with the aid of fresh and cold li~uid nitrogen
supplied via line 33 from li~uid gas tank 30. This nitrogen is
subse~uentl:y fed into conduits ll and 16 via lines 34 and 23.
Propellant gas compon~nts which are no~ condensed and do not
cause damage are released into the atmosphere near tank 35,
following co~densation, if the protective gas need of the plan~
i5 met.
Figure 3 shows ~an inventive plant for mechanical processing of
:~ :residue-containing packa~ing materials. This plant consists vf a
i ~ ,
materia:l feed and a conduit ll, which is filled with packaging
materlals r~ady ~o:r~processing via a traveller lla and which
r~leases~ the fed-in:packaying materials via a second traveller
llb to ~he act:ual pl:ant~ Conduit 11 is ~illed with nitrogen via
~ line 23.
-~
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~ ~ .
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~ o 93/22077 PCT/EP93/00988
,; ~ 21-
,
; ~: ~ Below conduit 11 is an opening and/or shredding device consisting
..
of two motor-driven (M) and counter-rotating drums, which shred
~ ~ the fe~-in p~ckaging materials with their attached cutting blades
!:, ~ or similar cutters. Two spray ~oz~lies 41~ and 41b for spraying
s:olvent onto the surfac~: of the rotating drum are arranged above
the shredder. Solvent is sprayiPd onto the shredded materials in
the same:way:with spray no~les installed at an angle below the
shredder drums.
Sp~ay~:nozzles~41~, 41b as~well as:42a and 42b are supplied with
fresh ~olvent via feed~ nes 22 and 22b, which is transported
after spraying, together with the~shre~ded materials to the
extrac~ion~and worki~ng container 13 below t~e shredder 12.
~:Çontaine~r:13 holds~the~extractionl~solvent mixture together with
~ the~solld:~componen:ts~o~ the packaging materials. A motorized
,ii ~ s~ti~rre~r 44~en~sur~es that solid:re~idues and solvent are in close
~: ~ contac~t~and~the:extr~ct:ion is~effeGtive. The extract is pumped
i~ rom;~c:ontainer~1:3 with a motoriz~d pu~p 45, through a line 17 and
:,i ~ into:~storage~contain~er 18 for prepolymer recovery, which is shown
~ in~F1gure:~:2~
,s ,~
A:~worm conv:e~y~r~14,-t~h~ lower~end of which lS submerged in the
`~ e~xt~ract/~o~lv~nt~mi~tur~e~, re~oves~s~olid packaging residues from
~:G~ai~er~ ~13. :~To~remove~-ext~ract~f~rom the solid packaging
mate~rl~al~res~idue~,~these~are~m~ved~with the worm conveyor through
~:; ~ a:washlng~segment which contains spraying noz~les 43 that are
po:inted tloward the~oll~eyor. Spraying noz21e~ 43 are suppliled
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~ith fresh solvent via lines 22 and 22a. The solvent i3prayed
onto worm conveyor 14 travels to cont~iner 13.
~,
The solid packaging residues moved along with worm conveyor 14
are fed via a batch funnel into a drying fa~ ty 15 where a
onveyor 46 moves the solid residues along under a heater 47.
From there, the materials are moved to a discharge conduit 16.
This: conduit 16 is sealed on the plant side with a slide 16a and
on the :solid material processing side with a slide 16b. Nitrogen
~, : c~n be fed into conduit 16 via a line 23a.
,1:
The processing plant consists of a motorized conveyor 48 which
ransports the materi~l through a magnetic separ~tor ~9. Wi~h
; the aid of this magnetic separator, the m~terial is se~arated
according ~o its magnetic qualities.
, ~
Th~ inve~tion-base~ plant according to Fig. 3 - with the
exception of the c04duits - lS operated w~ith protective gas.
Thiis protecti~ve gas iis fed via line ~4 into shxedder 1~ and
diatribu~ted throughout the plant.; Any protective gas leaving the
plant~, whlàh contains salvents and small amounts of nitrogen from
the~condu~ts, is drawn off ~ia lin~ 25 ~rom container 13 and/or
via line~5~a~from:the dryin~ facility 15 for solid packaging
esidues. lt may~be~useful to recirculate the protective gas if
the:amount of gas collecting from the pressurized cans i~ low.
It i~ u-~eful to have motorized valves in all lines if it is
necessary to regulate the flow of material in them.
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This is particularly true for the solvent feed-in lines ~o the
....
~ spray nozzles and washing facilit}es, thet operation of which can
t'j~`: be:stopped as soon as the material feeding and/or removal of
~ solid residués is finished.
. ~
L~ the pre~cedlng~descriptlon, the terms propel~ant, propellant
gas, protective gas and inert gas are used interchange~bly,
insofar~as~the operation of the actual plant is concerned. With
~ respec~to the conduit arrangement, thP protective and/or inert
< ~ gases~are~un~ersto~d:to~be traditional protective gases such as
1, ~ nitrogen and argon~
1, I ~
, ~
~ The facili~ties a~d plants used~for~the inventive method are
i! ~ commer~i`a~ y:~avail~ab~le or can be retrofitted by an expert to suit
this~purpos~ through~simple:~modification or adaptation of known
~!,J ,,',~ facilities~and:p~lants.~
.~ ~EPLAC~E~ENT P~GE
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