Note: Descriptions are shown in the official language in which they were submitted.
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Process and Device of Applying Mu~ti-Co~ponent Resins
and Use of Same
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Subject matter of the present in~ention is a process and
a device for applying multi-component resins to porous, gran-
ular material to be compactedj in particular, bulk material to
be compacted, optionally subsequently densified by rapping,
etc.. Typical such materials are, for example, ballasts for
rail vehicles, additional stone bottomings finer in grain onto
such ballasts, but also sand and pebble bottomings for road
construction to be cemented together without losing their
water permeability. With ballasts for rail vehicIes, cementing
is effected particularly in the transition zones between soft
and hard areas according to Applicantls German Patent Applica-
tion P 39 41 141.9. According to Applicant's German Patent
Application P 40 14 529.8, it may further be purposeful, par-
ticularly in curves, to increase the cross-sliding resistance
of railway sleepers on ballast. According to Applicant's
German Patent Application P 39 41 142.7, bottomings finer in
grain onto such ballasts are cemented using multi-component
resins to increase sound absorption and/or-cleanability of a
railway track. In particular, cementing of pebbles and sand,
with water permeability and porosity being retained, are per-
formed to ensure rapid drainage of surface water, and thereby
to reduce traffic noise even in rain.
~ n all these cases, as well as in similar fields of ap-
plication for cementing porous granular material and bulk ma-
terial using multi-component resins, it is required to apply a
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sufficient amount of said multi-component resins as uniformly
as possible such that, at least in the upper region, the parts
- are wetted over the total area, and adhesive bridges are
formed at least at the contact points. Any excess amount of
multi-component resin is to flow off downward and to coat
further material there. By no means the voids are to be
filled, as this would impede porosity of the cemented bulk
material as well as its permeability for water and other liq-
uids. Thus, the multi-component resins should not be too high-
ly viscous and, if possible, not thixotropic. The setting re-
action is to occur only after a sufficient depth of the bulk
material layer is coated with the multi-component resin but
not filled up to total volume. Since multi-component resins
generally are very reactive substances possibly leading to
irritation of skin and mucosae when processed, formation of
spray mists should be suppressed or completely avoided. More-
over, processing in tunnels or in closed spaces should be per-
formed without using solvents. In principle, this requirement
also holds in open air since solvents evaporating immediately
or subsequently result in an environmental load to be avoided
if ever possible. Nevertheless, the multi-component resins
must be applicable rapidly, simply, and safely to keep materi-
al and wage expenses as low as possible.
; This ambivalent, difficult, and partially contradictory
problem can be solved in a surprisingly simple manner in that
the components, physically separated from each other, at rela-
tively high pressure, are fed to a mixing chamber, mixed by
turbulent means in the mixing chamber, and applied as mixture
at relatively low pressure as thin curtain in laminar flow to
the material.
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Preferably, by selecting components and, optionally,
suitable additives, there is provided that viscosity of the
mixture is increased to from 300 to 1000 mPa s, but the sur-
face tension is decreased. These two properties make contribu-
tions in thak the thin curtain of the mixture does not break
up too early thus forming spray mists.
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Here, components and additives should be free of solvents
per se. Further, addition of solvents should be abandonded
completely.
: Fan spray nozzles operating at relatively low pressure
are particularly suited in generating a thin curtain of mix-
ture emerging in laminar flow. Suitable fan spray nozzles are
offered, for example, by the company Spraying Systems Deutsch-
land GmbH, Hamburg, under the designation FlatJet~ nozzles and
FloodJet~ nozzles. When using common low-viscosity materials
such as water and aqueous flushing solutions, these fan spray
nozzles provide a thin curtain of fine droplets including a
considerable amount of spray mists. Initially, it was not pre-
dictable that it is possible to discharge multi-component re-
sins using said fan spray nozzles in such way that the result-
ing curtain does not brea~ up too early and does not form
spray mists. In particular, if a pressure of only betweeen 2
and 6 bars (preferably from 3.5 to 5 bars) is present when the
mixture emerges from the nozzle, a thin curtain of the mixture
in laminar flow results. This curtain generally remains intact
over at least 10, mostly 20 cm, and only then is divided into
single jets and, eventually, into relatively large drops, but
by no means into the spray mists to be avoided.
Prior to discharge from the fan spray nozzle, the indi-
vidual components of the multi-component resin must be mixed
as quickly and intensively as possible, with the amount of
each mixture produced to be kept as small as possible to keep
losses of material upon interruption of operation as low as
possible. Thus, according to the invention, the components
must be mixed together turbulently in the mixing chamber.
Static mixers have especially proven worthwhile. These are
relatively short pipes having successive left-handed and
right-handed helix, thereby providing turbulent flow and per-
" fect mixing of the components.
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According to the invention, the feed lines for the indi
vidual components to the static mixer must be under relatively
high pressure. Pressures between 30 and 200 bars (preferably
from 50 to 150 bars) have proven suitable. This relatively
high pressure is diminished so far within the static mixer
that the final mixture emerges from the fan spray nozzle at a
residual pressure of only from 2 to 6 bars.
The residence times of the multi-component resin in the
mixing chamber or the static mixer are substantially shorter
than the so-called pot life of the final mixtures. Thus, the
mixture applied to the bulk material in a fashion according to
the invention retains its relatively low viscosity for a time
sufficient to spreadingly and wettingly pass a sufficiently
thick layer of bulk material.
By no means ho~ever, the components of the multi-com-
ponent resins may be allowed to come into contact within from
the pipelines to the mixing chamber or even to react within
the feed lines. Thus, it is convenient to secure each of the ~-
separate feed lines for the components by check valves.
Furthermore, it is most convenient to connect each of these
feed lines separately to a compressed-air line which in turn
is secured by check valves. In case one component is stopped
or the feed of one component is interrupted on purpose or
without purpose, the compressed air provides for discharge of
the feed line to the mixing chamber and from there to the fan
spray nozzle. After a short time, a thin curtain of a liquid-
air mixture will emerge there which immediately can be per-
cepted in both optical and acoustic terms and should result in
interruption of the overall processing operation.
Pipelines and mixing chamber are also cleaned by com-
pressed air upon intended interruption or completion of the
processing operation. Further cleaning using solvents is not
required in general.
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Thus, object of the present invention is, at first, the
process according to the above process claims. Another object
of the present invention is the device for performing said
process, consisting of
a) separate feed lines for the components being under
relatively high pressure
b) a mixing chamber, preferably designed as a static
mixer
c) a fan spray nozzle for relatively low pressure
d) preferably separate compressed-air lines leading to
the feed lines for the components, and
e) check valves provided at both beginning and end of
each feed line for the componants as well as in the com-
pressed-air lines.
Thus, in the simplest case, the device constists of se-
parate feed lines for the components being under relatively
high pressure, a mixing chamber and a fan spray nozzle for
relatively low pressure. Preferably, the device has separate
compressed-air lines leading to the feed lines for the com-
ponents. Conveniently, each of the feed lines for the com-
ponents and the compressed-air lines are secured by check
valves, so that unintentional penetration of one or all the
components into parts of the device other than mixing chamber
and fa~ spray nozzle are avoided.
When using static mixers, the device can be handled re-
latively simply and easily, and thus, manual handling is quite
well. The feed of the device is preferably effected using
flexible tubes. Thus, with a two-component resin, two tubes
for the components and one tube for compressed air are suf-
ficient.
Preferred multi-component resins are epoxide resin ad-
hesives as well as polyurethane resin adhesives. For special
uses, a third or a fourth liquid component may be dosed readi-
ly, particularly, where surface tension, viscosity, and reac-
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tion time are to be ad~usted to each special situation, or
these additional components on premixing give rise to de-
; creasing stability of the major components.
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Other additional components may be flame retardants, de-
foamers, sllspensions of color pigments, etc., intended to be
used in certain places or especially critical areas only.
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In Figure 1 in the annex, there is represented schemati-
cally a device according to the invention for applying a two-
; component resin having components A and B.
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In this figure,
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~ 1 represents a fan spray nozzle
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2 represents a static mixer
3A represents the feed line for component A
3B represents the feed line for component B
4 represents the separate feed lines for compressed
air
represents the check valves in the feed lines for
the components and the feed lines for compressed
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i Further objects of the invention are utilizations of this
process and device for the application of multi-component
resins
. a) to increase sound absorption andjor cleanability of
a railway trackj where a stone bottoming ranging in grain size
below 63 mm, preferably below 30 mm diameter is applied onto
the railway and is compacted by spraying with a spreading
multi-component epoxide resin adhesive;
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b) to increase cross-sliding resistance of railway
sleepers on ballast, where the ballast ls sprayed with a
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spreading multi-component epoxide resin adhesive or a multi-
component polyurethane resin adhesive; and
c) to smooth the transition between a soft and a hard
railway track, where the soft track succeeding the end of the
hard track is compacted by spraying with a spreading multi-
component epoxide resin adhesive or a multi-component poly-
urethane resin adhesive, and the compacting is effected de-
creasingly with increasing distance from the hard track by
decreasing the amount of adhesive applied;
d) to cement pebbles and sand in road construction,
with water permeability and porosity being retained.
To increase sound absorption and/or cleanability of a
railway track, the stone bottoming ranging in grain size below
63 mm, preferably below 30 mm diameter is applied onto the
railway and is compacted by spraying with a spreading multi-
component epoxide resin adhesive.
Due to the narrow range in grain size, the layer formed
according to this process has a relatively high amount of
voids, but is, nevertheless, compacted, because the spreading
adhesive moves around the grains, thus always reaching the
contact points of the grains, binding them together after cur-
ing, but in advance, optionally, flowing downward to the next
grain, etc. - steadily moving along the grain surface, and not
filling the voids. Important in this connection is the range
in grain size - preferably below 25 mm, more preferably below
20 mm - being far below that of ballast optionally present,
and which, depending on whether sound absorption or cleanabi-
lity is deemed more desirable, more that way or the other, may
be uniformly seleceted to serve both functions as well.
As a rule, the range in grain size will be limited to a
grain size ratio of from 1:2 to 1:3 (smallest grain to largest
grain). Grainings of from 2 to 4 mm, from 4 to 11 mm, and from
8 to 16 mm have proven convenient.
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Likewise, the stone bottoming may be applied several
times in different layers. ~ere, if grain size increases from
bottom to top, sound absorption i5 improved. The sound will be
forced to branch on its way downwards and fades away.
The stone bottoming may consist of round grains or stone
chips.
The layer is to serve sound absorption predominantly on
and in buildings, as well as on bridges and in tunnels, par-
ticularly on solid road, i.e., where railways are laid onto
concrete. The layer is to serve cleanability predominantly in
I railway stations. The firmness of the layer surface - the
depth of compacting may be controlled via amount of spray-
applied adhesive - permits, for example, cleaning by steam jet
blowing and simultaneous suction.
It is an important advantage that the layer produced ac-
` cording to the invention is drainable. This is not the case
with prior known layers made of concrete or steel.
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Another advantage is that it is possible to break up thelayer for purposes of repair, e.g., at a sleeper, and then to
restore it using the same stone material. It is pointed out
that, as a rule, the layer extends as high as the upper edge
of the sleeper. It also protects from stoning flying about.
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Using the following embodiment, this application is ex-
plained in greater detail:
A threefold stone bottoming is applied to a track embank-
ment, depending on the conditions, to a total thickness of
from 20 to 25 cm. The bottom layer consists of quartz graining
(round grain), grain size from 2 to 4 mm, the middle layer
consists of stone chip graining (basalt or limestone), grain
size of from 4 to 11 mm, and the top layer consists of stone
chip graining (basalt or limestone), grain size of from 8 to
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16 mm. The bottom and middle layer each make up for about 30~,
the top layer for about 40% of the total thickness.
Thereupon is sprayed an epoxide resin adhesive in an
amount of, for example, 2 k~/m .
The adhesive is a two~component adhesive.
The resin component consists of non-brominated bis-
phenol A resins and cycloaliphatic resins. Added thereto are
monofunctional and/or bifunctional reactive thinners, phos-
phoric esters as flame retardants, silicic esters as primers,
and a silicone defoamer.
The hardener component consists of adducts of amines,
amides, phenol-free Mannich bases or mixtures thereof, benzyl
alcohol as promoter, silicic ester as primer, and silicone
defoamer.
The adhesive forms a uniformly compacted layer down to a
depth of about 10 cm. Beneath, the compacting is more loosely,
and then only here and there.
In addition to the weight of the trains, a centrifugal
force acts upon the railway tracks in curves. The transversal
force thus acting upon the sleepers may be neutralized for a
certain train velocity by banking the outward track. As a
rule, however, the railways must be run by trains having dif-
ferent velocities. Contemplating slow goods trains, banking is
limited.
To increase-cross-sliding resistance of railway sleepers
on ballast, ~he latter is sprayed with a spreading multi-com-
ponent epoxide resin adhesive or a multi-component poly-
urethane resin adhesive.
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The spreading adhesive moves around the crushed stones,
thus al~ays reaching the contact points of the stones, binding
them together after curing, but in advance, optionally, flow-
ing downward to the next stone, etc. - steadily moving along
the stone surface, and not filling the voids. The adhesive,
uniformly spread by spraying, continuously compacts a flat
surface layer of the ballast, forming stalaktites thereunder.
With larger amounts of adhesive, these stalaktites are formed
in somewhat smaller distances to each other. In part, they
reach down as far as to the bottom of the ballast, forming an
additional toe there. Decreasing the amount of adhesive re-
sults in greater distance and diminished lengths of the sta-
laktites. Thus, using the amount of adhesive applied, con-
trolled compacting of the ballast may be achieved. The railway
sleepers embedded into the ballast are accordingly fixed more
strongly.
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Fixation still improves when the railway sleepers are
~i sprayed as well, thus gaining the same binding with the bal-
last as the ballast within itself. -
The amount of adhesive to be applied depends on the con- -
ditions present. As a general rule, it will be more than
2 1/m2, mostly betweeen 5 and 8 1/m2.
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An example for an adhesive to be applied is given as
follows:
The resin component consists of non-brominated bis-
phenol A resins and cycloaliphatic resins. Added thereto are
monofunctional and/or b.ifunctional reactive thinners, phos-
phoric esters as flame retardants, silicic esters as primers,
and a silicone defoamer.
The hardener component consists of adducts of amines,
amides, phenol-free Mannich bases or mixtures thereof, benzyl
alcohol as promoter, silicic ester as primer, and silicone
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defoamer. Likewise, a multi-component polyurethane resin ad-
hesive were possible instead.
The adhesive is incorporated in an amount of from 6 to
7 kg/m , for instance.
A special advantage is that also existing railway lines
may be improved in simple fashion by the process according to
the invention.
A soft railway is understood to be railway tracks laid
onto ballast, and a hard railway is understood to be railway
tracks laid onto or into a building which, as a rule, is made
of concrete. The ballast is more flexible than concrete. With
20 t of weight on the axle, the tracks give way for about from
1.5 to 4 mm, mostly about 3 mm, on concrete, for only from 0.5
to 1.5 mm, mostly about 1 mm, which is due to the plastic
layer betweeen concrete and tracks.
This difference gives rise to an impact or shock, as the
wheels make the transition from one railway to the other.
To smooth the transition between a soft and a hard rail-
way track, the soft track succeeding the end of the hard track
is compacted by spraying with a spreading multi-component
epoxide resin adhesive or a multi-component polyurethane resin
adhesive, and the compacting is effected decreasingly with
increasing distance from the hard track by decreasing the
amount of adhesive applied.
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Preferably, the compacting initially is perfo~med con-
tinuously for some way, and then, decreasingly.
The spreading adhesive moves around the crushed stones,
thus always reaching the contact points of the stones, binding
them together after curing, but in advance, optionally, flow-
ing downward to the next stone, etc. - steadily moving along
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the stone surface, and not filling the voids. The invention
includes the recognition that such compacting may be con-
trolled very well via amount of adhesive applied, to a large
degree via local distribution of the adhesive. The adhesive,
uniformly spread by spraying, continuously compacts a flat
surface layer of the ballast, forming stalaktites thereunderO
With larger amounts of adhesive, these stalaktites are formed
in somewhat smaller distances to each other. In part, they
reach down as far as to the bottom of the ballast, forming an
additional toe there. Decreasing the amount of adhesive re-
sults in greater distance and diminished lengths of the
stalaktites.
In this way, a kind of point lattice forms as a mono-
lithic block, which lattice, depending on its density, holds
together the ballast to a greater or lesser extent, and, de-
pending on its depth extension, in a flatter or higher layer,
thus more or less decrasing the low mobility of the ballast
stones with respect to each other, and thus decreasing ballast
flexibility.
In addition to the reversible mobility of the ballast
stones in elastic deformation, the irreversible displacements
of the ballast stones with respect to each other, occurring in
the course of time, are reduced, which cause the ballast to
give way and thus, further result in shock at the transition
from soft to hard way and vice versa.
For instance, the section of constant stability has a
length of from 5 to 15 m, the section of decreasing stability,
for example, has a length of from 10 to 20 m.
Depending on its composition, the adhesive will be ap-
plied in an amount of from 5 to 8 l/m2 which reduces to from 1
to 2 l/m2.
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Figure 2 represents an embodiment of the invention. It
shows a vertical longitudinal section of a railway, a sector
being drawn in magnification.
A railway track having rails 11 on sleepers 12 is running
from natural ground onto a bridge 14. Above the natural ground
the sleepers 12 are carried on ballast 15. On the bridge 14,
they directly lie on concrete.
By spraying an adhesive penetrating the ballast onto a
section 16 succeeding the bridge 14 of, e.g., 10 m in length
and then onto a section 17 of, e.g., 15 m in length, the bal-
last 15 is compacted in a uniform and decreasing manner, re-
spectively. The decrease in compacting results in the first
place from a decreasing average penetration depth of the ad-
hesive. Another small proportion of said decrease is due to
greater distance betweeen the points where the adhesive ex-
tends downwards in the form of stalaktites 18.
The adhesive is a two-component adhesive.
The resin component consists, for instance, of non-
brominated bisphenol A resins and cycloaliphatic resins. Added
thereto are monofunctional and/or bifunctional reactive thin-
ners, phosphoric esters as flame retardants, silicic esters as
primers, and a silicone defoamer.
; The hardener component consists of adducts of amines,
amides, phenol-free Mannich bases or mixtures thereof, benzyl
alcohol as promoter, silicic ester as primer, and silicone
defoamer. Likewise, a multi-component polyurethane resin ad-
hesive were possible instead.
In section 16, the adhesive has been incorporated in an
amount of from 6 to 7 kg/m2, and in section 17 uniformly de-
creasing to 1 kg/m2.
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