U.S. patent application number 13/129148 was filed with the patent office on 2011-09-08 for recycling of road surfacings.
This patent application is currently assigned to BASF SE. Invention is credited to Fikri Emrah Alemdaroglu, Marcus Leberfinger, Heinrich Mohmeyer, Nils Mohmeyer, Thomas Stuehrenberg.
Application Number | 20110217118 13/129148 |
Document ID | / |
Family ID | 42027622 |
Filed Date | 2011-09-08 |
United States Patent
Application |
20110217118 |
Kind Code |
A1 |
Mohmeyer; Nils ; et
al. |
September 8, 2011 |
RECYCLING OF ROAD SURFACINGS
Abstract
The present invention relates to a process for the production of
roads, tracks, and other areas used by traffic, by producing a
mixture comprising ground road surfacing, mineral material, and/or
glass, a polymer reaction mixture and, if desired, further
additions, and applying it to a substrate material, and hardening
it. The present invention further relates to roads, tracks, and
other areas used by traffic, obtainable by a process of this
type.
Inventors: |
Mohmeyer; Nils; (Osnabrueck,
DE) ; Leberfinger; Marcus; (Georgsmarienhuette,
DE) ; Stuehrenberg; Thomas; (Osnabrueck, DE) ;
Alemdaroglu; Fikri Emrah; (Stemshorn, DE) ; Mohmeyer;
Heinrich; (Alfeld/Leine, DE) |
Assignee: |
BASF SE
Ludwigshafen
DE
|
Family ID: |
42027622 |
Appl. No.: |
13/129148 |
Filed: |
November 23, 2009 |
PCT Filed: |
November 23, 2009 |
PCT NO: |
PCT/EP09/65638 |
371 Date: |
May 13, 2011 |
Current U.S.
Class: |
404/31 ;
404/72 |
Current CPC
Class: |
E01C 7/30 20130101 |
Class at
Publication: |
404/31 ;
404/72 |
International
Class: |
E01C 11/00 20060101
E01C011/00 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 25, 2008 |
EP |
08169895.3 |
Claims
1. A process for producing a road, a track, or a different area
bearing traffic, the process comprising: producing a first mixture
comprising ground road surfacing, at least one selected from the
group consisting of a mineral material and glass, a polymer
reaction mixture, and optionally, at least one further addition;
(ii) applying the first mixture to a substrate material; and (iii)
hardening the first mixture.
2. The process of claim 1, wherein the polymer reaction mixture is
a mixture for producing a polyurethane.
3. The process of claim 2, wherein the polymer reaction mixture
comprises a compound which improves adhesion.
4. The process of claim 1, wherein the polymer reaction mixture is
obtained via mixing a) at least one isocyanate with b) at least one
compound having at least two hydrogen atoms reactive toward
isocyanate, c) at least one selected from the group consisting of a
chain extender and a crosslinking agent, d) optionally, at least
one catalyst, and e) optionally, at least one further additive.
5. The process of claim 1, wherein a proportion of the polymer
reaction mixture is from 1 to 20% by weight, based on a total
weight of the first mixture.
6. The process of claim 1, wherein a proportion of ground road
surfacing is smaller than 95% by weight, based on a total weight of
a mixture composed of ground road surfacing and mineral material in
the first mixture.
7. A top layer or load-bearing layer obtained by the process of
claim 1, wherein the top layer or load-bearing layer is suitable
for a road, a track, or a different area bearing traffic.
8. The process of claim 2, wherein the polymer reaction mixture is
obtained via mixing a) at least one isocyanate with b) at least one
compound having at least two hydrogen atoms reactive toward
isocyanate, c) at least one selected from the group consisting of a
chain extender and a crosslinking agent, d) optionally, at least
one catalyst, and e) optionally, at least one further additive.
9. The process of claim 3, wherein the polymer reaction mixture is
obtained via mixing a) at least one isocyanate with b) at least one
compound having at least two hydrogen atoms reactive toward
isocyanate, c) at least one selected from the group consisting of a
chain extender and a crosslinking agent, d) optionally, at least
one catalyst, and e) optionally, at least one further additive.
10. The process of claim 2, wherein a proportion of the polymer
reaction mixture is from 1 to 20% by weight, based on a total
weight of the first mixture.
11. The process of claim 3, wherein a proportion of the polymer
reaction mixture is from 1 to 20% by weight, based on a total
weight of the first mixture.
12. The process of claim 4, wherein a proportion of the polymer
reaction mixture is from 1 to 20% by weight, based on a total
weight of the first mixture.
13. The process of claim 8, wherein a proportion of the polymer
reaction mixture is from 1 to 20% by weight, based on a total
weight of the first mixture.
14. The process of claim 9, wherein a proportion of the polymer
reaction mixture is from 1 to 20% by weight, based on a total
weight of the first mixture.
15. The process of claim 1, wherein the polymer reaction mixture is
a mixture for producing an epoxy resin.
16. The process of claim 15, wherein the polymer reaction mixture
comprises a compound which improves adhesion.
17. The process of claim 15, wherein a proportion of the polymer
reaction mixture is from 1 to 20% by weight, based on a total
weight of the first mixture.
18. The process of claim 16, wherein a proportion of the polymer
reaction mixture is from 1 to 20% by weight, based on a total
weight of the first mixture.
19. The process of claim 15, wherein a proportion of ground road
surfacing is smaller than 95% by weight, based on a total weight of
the mixture composed of ground road surfacing and mineral
material.
20. A top layer or load-bearing layer obtained by the process of
claim 15, wherein the top layer or load-bearing layer is suitable
for a road, a track, or a different area bearing traffic.
Description
[0001] The present invention relates to a process for the
production of roads, tracks, and other areas used by traffic, by
producing a mixture comprising ground road surfacing, mineral
material, and/or glass, a polymer reaction mixture and, if desired,
further additions, and applying it to a substrate material, and
hardening it. The present invention further relates to roads,
tracks, and other areas used by traffic, obtainable by a process of
this type.
[0002] Further embodiments of the present invention are found in
the claims, in the description, and in the examples. The
abovementioned features of the subject matter of the invention, and
the features that will be explained below, can of course be used
not only in the respective stated combination but also in other
combinations, without exceeding the scope of the invention.
[0003] Roads are mostly produced from asphalt, by applying a
mineral mixture, mostly with bitumen as binder, if appropriate in a
plurality of layers, to the substrate. Road surfacings using a
plastic as binder are also known, for example as described in DE
19605990 and DE 19651749.
[0004] Bitumen-based roads usually have to be renewed after about
12 to 18 years, as a function of quality and loading, and after as
little as from 6 to 7 years if the top layers have open pores. For
this, the old asphalt is removed entirely or to some extent. Small
amounts of the material removed can, if appropriate, be recycled
with the same grain size distribution up to a level which is
preferably 15% by weight. For this, the material must be conveyed
to an asphalt mixing plant, where it is mixed at temperatures of
about 180.degree. C. with fresh bitumen and also with mineral
material. The resultant asphalt is then in turn conveyed from the
asphalt mixing plant to the installation site. This procedure
causes severe environmental pollution, in particular by virtue of
the truck traffic necessary for this purpose, and also by virtue of
the high energy consumption in the asphalt mixing plant. A further
factor is that asphalt which cannot be reused, the binder of which
still comprises a proportion of tar, has to be discarded as special
waste, because tar is toxic.
[0005] It was an object of the present invention to provide a
process which can produce roads, tracks, and other areas used by
traffic, and which reduces pollution of the environment.
[0006] The object of the invention is achieved via a process for
the production of roads, tracks, and other areas used by traffic,
by producing a mixture comprising ground road surfacing, mineral
material, and/or glass, a polymer reaction mixture and, if desired,
further additions, and applying it to a substrate material, and
hardening it.
[0007] Roads, tracks, and other areas used by traffic are usually
composed of a plurality of layers. These have at least one bound
top layer at the surface, and also, if appropriate, further bound
and unbound, deeper, layers. The bound deeper layers are usually
what are known as the load-bearing layers, and the unbound deeper
layers are usually base layers composed of rubble and gravel. The
usual materials used as binders for the bound top layers and
load-bearing layers are cement, plastic, or bitumen.
[0008] The process of the invention relates here to the production
of bound layers. These can either be load-bearing layers or top
layers. The main difference between the load-bearing layers and top
layers is the average diameter of the mineral material used. The
process of the invention preferably relates to the production of
top layers. The substrate material used can be any desired
material, examples being sand, earth, loam, concrete, stone.
Substrate materials are preferably base layers and/or load-bearing
layers.
[0009] According to the invention, ground road surfacing means
either ground or broken top layers or else ground or broken
load-bearing layers, and ground rubble layers or ground gravel
layers. The ground road surfacing is preferably ground bound
layers, in particular ground top layers. The binder for the ground
bound layers here is preferably a binder based on polymers or based
on bitumen, in particular based on bitumen. This particularly
preferred variant utilizes not only the thermoplastic or
viscoelastic properties of bitumen but also the high-temperatures
of the polymer binder. The grain size distribution of the ground
road surfacing here can be adjusted in a known manner by adapting
the grinding conditions or removing undesired grain sizes.
According to the invention, it is also possible to use
pored-asphalt-based top layers as a base for ground road
surfacing.
[0010] The mineral material used here can comprise any known
mineral material. By way of example, sand or ground stone, known as
broken material, can be used here, where sand has a mainly round
surface and broken material has edges and fracture surfaces. It is
particularly preferable that the mineral material used comprises a
material which is mainly composed of broken material.
[0011] The glass used preferably comprises ground or broken glass.
Broken glass here is preferably colored glass, permitting, for
example, application of markings. Glass can be used here together
with mineral material or instead of mineral material. It is
preferable to use only mineral material, and no glass.
[0012] The grain size distribution of the mixture composed of
ground road surfacing and of mineral material and/or glass is
particularly preferably one based on the specifications encountered
in bituminous road construction, being a function of the intended
use, for example for load-bearing layers and top layers, examples
being stone-filled mastic asphalt or drainable asphalt. The grain
size distribution can be adjusted either via adjustment of the
grain sizes of the ground road surfacing or else via use of mineral
material with certain grain size distribution, or both. The ground
road surfacing and the mineral material here can be mixed in any
ratio by weight. The proportion of ground road surfacing is
preferably smaller than 95% by weight, particularly preferably from
5 to 80% by weight, and in particular from 10 to 70% by weight,
based on the total weight of the mixture composed of ground road
surfacing and of mineral material.
[0013] A polymer reaction mixture here means a mixture capable of
reacting to give a polymer. These mixtures encompass those
comprising molecules which by way of example can react to give the
polymer via chain-growth reactions, e.g. free-radical
polymerization, or ionic polymerization, examples being unsaturated
compounds, or molecules capable of entering into polycondensation
reactions, examples being polyalcohols, or molecules capable of
entering into polyaddition reactions, examples being polyols and
polyisocyanates, or those such as epoxides. Polymer reaction
mixtures of the invention are preferably liquid at 40.degree.
C.
[0014] The polymer reaction mixture preferably involves a mixture
for the production of an epoxy resin or of a polyurethane. In
particular, it involves a mixture for the production of a
polyurethane, a polyurethane reaction mixture. The polymer reaction
mixture here preferably comprises in essence no solvents.
[0015] The polymers obtained from a polymer reaction mixture are
preferably compact, and this means that they comprise practically
no pores. A feature of compact polymers, when compared with
cellular polymers, is greater mechanical stability. Bubbles can
occur within the polymer and are mostly not critical. However, they
should be minimized as far as possible. It is moreover preferable
that the resultant polymers are hydrophobic. This suppresses
degradation of the polymers by water.
[0016] Polymer reaction mixtures of the invention preferably
comprise compounds for improving adhesion to the recycling material
and also to the mineral material. By way of example, these are
hydroxy- or alkoxyaminosilane compounds of the general formula
(I)
##STR00001##
in which X are, independently of one another, OH, CH.sub.3,
O[CH.sub.2].sub.pCH.sub.3; Y is [CH.sub.2].sub.t,
[(CH.sub.2).sub.rNH(CH.sub.2).sub.s].sub.b,
[(CH.sub.2).sub.rNH(CH.sub.2).sub.sNH(CH.sub.2).sub.z].sub.b; R, R'
is H, [CH.sub.2].sub.tCH.sub.3; t is 0-10; n is 1-3; p is 0-5; m is
4-n; r, s, b, and z are, independently of one another, 1-10.
[0017] The alkoxyaminosilane compound (I) is generally a
trihydroxy-, dialkoxy- or trialkoxyaminosilane compound. Preferred
alkoxy radicals X are methoxy and ethoxy. The amino group must be
an amino group reactive toward isocyanate groups, i.e. a primary or
secondary amino group. Preferred alkyl radicals R are hydrogen,
methyl, and ethyl.
[0018] The alkoxyaminosilane compound (I) preferably involves a
trihydroxyaminosilane compound or a trialkoxyaminosilane compound,
where, in formula (I), X=OH or O[CH.sub.2].sub.pCH.sub.3, and p=0,
1.
[0019] It is further preferable that the alkoxyaminosilane compound
(I) involves an alkoxydiaminosilane compound, where, in formula
(I), Y=[CH.sub.2].sub.1NH[CH.sub.2].sub.s, and r and s are
identical or different, being 1 or 2. Examples are
[CH.sub.2].sub.3NH[CH.sub.2].sub.2,
[CH.sub.2].sub.2NH[CH.sub.2].sub.2, [CH.sub.2]NH[CH.sub.2],
[CH.sub.2].sub.3NH[CH.sub.2].sub.3,
[CH.sub.2CH(CH.sub.3)CH.sub.2]NH[CH.sub.2].sub.2 and
[CH.sub.2].sub.2NH[CH.sub.2].sub.3.
[0020] The alkoxyaminosilane compound (I) in particular involves a
trialkoxydiaminosilane compound, where, in formula (I),
X=O[CH.sub.2].sub.pCH.sub.3, where p=0, 1, and
Y=[CH.sub.2].sub.rNH[CH.sub.2].sub.s, where r and s are identical
or different, being 1 or 2.
[0021] Particularly preferred alkoxyaminosilane compounds (I) are
3-triethoxysilyipropylamine,
N-(3-trihydroxysilylpropyl)ethylenediamine,
N-(3-trimethoxysilylpropyl)ethylenediamine, and
N-(3-methyldimethoxymethylsilyl-2-methylpropyl)ethylenediamine.
[0022] The polymer reaction mixture here generally comprises a
concentration of from 0.01 to 10% by weight, preferably from 0.1 to
1% by weight, based on the total weight of the polymer reaction
mixture, of the compounds for improving adhesion. The compound for
improving adhesion here can also have reacted previously with
further constituents of the polymer reaction mixture, for example
by way of any OH group present.
[0023] For the purposes of this invention, a mixture for the
production of an epoxy resin means a mixture which comprises
compounds comprising epoxy groups, and comprises suitable
hardeners. The mixtures here are capable, starting from the
compounds comprising epoxy groups, of forming epoxy resins by way
of said epoxy groups through polyaddition, using suitable
hardeners. The invention uses the expression "a mixture for the
production of an epoxy resin" when conversion in the reaction,
based on the epoxy groups used for the production of the epoxy
resin, is preferably smaller than 90%, particularly preferably
smaller than 75%, and in particular smaller than 50%.
[0024] Compounds used comprising epoxy groups are preferably
compounds which have at least two epoxy groups and which are liquid
at room temperature. Mixtures of different compounds comprising
epoxy groups can also be used here. It is preferable that said
compounds are hydrophobic or that the mixtures comprise at least
one compound which is hydrophobic and which comprises epoxy groups.
Hydrophobic compounds of this type are by way of example obtained
via a condensation reaction of bisphenol A or bisphenol F with
epichlorohydrin. Said compounds can be used individually or in the
form of a mixture.
[0025] In one embodiment, mixtures are used which are composed of
above-mentioned hydrophobic compounds, comprising epoxy groups,
with self-emulsifiable hydrophilic compounds, comprising epoxy
groups. These hydrophilic compounds are obtained here via
introduction of hydrophilic groups into the main chain of the
compound comprising epoxy groups. Compounds of this type and
processes for their production are disclosed by way of example in
JP-A-7-206982 and JP-A-7-304853.
[0026] Hardeners used comprise compounds which catalyze the
homopolymerization of the compounds comprising epoxy groups, or
which react covalently with the epoxy groups or with the secondary
hydroxy groups, examples being polyamines, polyaminoamides,
ketimines, carboxylic anhydrides, and melamine-urea-phenol adducts
and formaldehyde adducts. It is preferable to use ketimines,
obtainable via reaction of a compound having a primary or secondary
amino group, e.g. diethylenetriamine, triethylenetetramine,
propylenediamine, or xylylenediamine, with a carbonyl compound,
such as acetone, methyl ethyl ketone, or isobutyl methyl ketone, or
to use alphatic, alicyclic, and aromatic polyamine compounds and
polyamide compounds. Hardeners used with particular preference are
ketimines or compatible mixtures comprising ketimines.
[0027] The ratio of reactive groups in the hardener to epoxy groups
is preferably from 0.7:1 to 1.5:1, particularly preferably from
1.1:1 to 1.4:1.
[0028] During the production of the epoxy resins, it is also
possible to add further additives, such as solvents, reactive
diluents, fillers, and pigments, alongside the compounds comprising
epoxy groups, and alongside the hardeners used. Additives of this
type are known to the person skilled in the art.
[0029] A polyurethane reaction mixture is a mixture composed of
compounds having isocyanate groups and compounds having groups
reactive toward isocyanates, where the reaction conversion, based
on the isocyanate groups used for the production of the
polyurethane reaction mixture, is preferably smaller than 90%,
particularly preferably smaller than 75%, and in particular smaller
than 50%. The compounds having groups reactive toward isocyanates
here comprise not only high-molecular-weight compounds, such as
polyether- and polyesterols, but also low-molecular-weight
compounds, such as glycerol, glycol, and also water. If the
reaction conversion, based on the isocyanate group, is greater than
90%, the term polyurethane is used below. A polyurethane reaction
mixture here can also comprise further reaction mixtures for the
production of polymers. Examples of further reaction mixtures that
can be used for the production of polymers are reaction mixtures
for the production of epoxides, of acrylates, or of polyester
resins. The proportion of further reaction mixtures for the
production of polymers here is preferably less than 50% by weight,
based on the total weight of the polyurethane reaction mixture. It
is particularly preferable that the polyurethane reaction mixture
comprises no further reaction mixtures for the production of
polymers.
[0030] The polyurethane reaction mixture can involve what are known
as moisture-curing systems. These comprise isocyanate prepolymers
which form polyurethanes or polyureas via addition of water or via
humidity, mainly by forming urea groups.
[0031] It is preferable to use what are known as two-component
systems for the production of the polyurethane reaction mixture.
For this, an isocyanate component comprising compounds having
isocyanate groups, and a polyol component comprising compounds
having groups reactive toward isocyanates are mixed in quantitative
proportions such that the isocyanate index is in the range from 40
to 300, preferably from 60 to 200, and particularly preferably from
80 to 150.
[0032] For the purposes of the present invention, isocyanate index
here means the stoichiometric ratio of isocyanate groups to groups
reactive toward isocyanate, multiplied by 100. Groups reactive
toward isocyanate here means any of the groups which are comprised
in the reaction mixture and which are reactive toward isocyanate,
and this includes chemical blowing agents, but not the isocyanate
group itself.
[0033] The polyurethane reaction mixture is preferably obtained by
mixing of a) isocyanates with b) relatively high-molecular-weight
compounds having at least two hydrogen atoms reactive toward
isocyanate, and also, if desired, c) chain extenders and/or
crosslinking agents, d) catalysts, and e) other additives.
Compounds particularly preferably used as components a) and b), and
also, if desired, c) to e) are those which lead to a hydrophobic
polyurethane reaction mixture and to a hydrophobic
polyurethane.
[0034] Isocyanates a) that can be used are in principle any of the
room-temperature-liquid isocyanates having at least two isocyanate
groups. Aromatic isocyanates are preferably used, particularly
preferably isomers of tolylene diisocyanate (TDI) and of
diphenylmethane diisocyanate (MDI), in particular mixtures composed
of MDI and of polyphenylene polymethylene polyisocyanates (crude
MDI). The isocyanates can also have been modified, for example by
incorporating isocyanurate groups and carbodiimide groups, and in
particular by incorporating urethane groups. The last-mentioned
compounds are produced via reaction of isocyanates with a
substoichiometric amount of compounds having at least two active
hydrogen atoms and are usually termed NCO prepolymers. Their NCO
content is mostly in the range from 2 to 32% by weight. The
isocyanates a) preferably comprise crude MDI, with resultant
increase in the stability of the polyurethane obtained.
[0035] In applications of the inventive process where high
colorfastness is important, it is preferable to use mixtures
comprising aliphatic isocyanates and aromatic isocyanates. It is
particularly preferable to use exclusively aliphatic isocyanates.
In one particular embodiment, an overlayer composed of polyurethane
based on an aliphatic isocyanate can be used, in order to protect
the top layer based on aromatic isocyanate from yellowing. The
overlayer here can also comprise mineral material. Preferred
representative aliphatic isocyanates are hexamethylene diisocyanate
(HDI) and isophorone diisocyanate (IPDI). Because the aliphatic
isocyanates have high volatility, they are mostly used in the form
of their reaction products, in particular in the form of biurets,
allophanates, uretonimines, or isocyanurates.
[0036] The isocyanates a) can also be used in the form of their
prepolymers. For this, the isocyanates a) are reacted in a known
manner in excess with compounds reactive toward isocyanate, for
example with the relatively high-molecular-weight compounds listed
under b), having at least 2 groups reactive toward isocyanate, to
give prepolymers.
[0037] The relatively high-molecular-weight compounds b) used,
having at least two hydrogen atoms reactive toward isocyanate
preferably comprise compounds which have, as group reactive toward
isocyanate, hydroxy groups or amino groups. Amino groups as groups
reactive toward isocyanates lead to formation of urea groups, which
in turn harden to give a polyurethane which is mostly brittle, but
which has very good hydrolysis resistance and chemicals resistance.
The relatively high-molecular-weight compounds b) used, having at
least two hydrogen atoms reactive toward isocyanate preferably
comprise polyhydric alcohols, since these generally react more
slowly than compounds having amino groups and thus permit longer
processing times. Given appropriate high molar masses, for example
greater than 1500 g/mol, the use of polyhydric alcohols moreover
gives a relatively elastic material.
[0038] The relatively high-molecular-weight, polyhydric alcohols
used can by way of example comprise polyethers or polyesters.
Further compounds having at least two hydrogen atoms reactive
toward isocyanate groups can be used together with the compounds
mentioned.
[0039] Because of their high hydrolysis resistance, polyether
alcohols are preferred as relatively high-molecular-weight
compounds b) having at least two hydrogen atoms reactive toward
isocyanate. These are produced by conventional and known processes,
mostly via an addition reaction of alkylene oxides onto
H-functional starter substances. The functionality of the polyether
alcohols used concomitantly is preferably at least 2, their hydroxy
number being at least 10 mg KOH/g, preferably at least 15 mg KOH/g,
in particular in the range from 20 to 600 mg KOH/g. They are
produced in a conventional manner via reaction of at least
difunctional starter substances with alkylene oxides. Starter
substances used can preferably comprise alcohols having at least
two hydroxy groups in the molecule, examples being propylene
glycol, monoethylene glycol, diethylene glycol, dipropylene glycol,
tripropylene glycol. Starter substances of relatively high
functionality can preferably be glycerol, trimethylolpropane,
pentaerythritol, sorbitol, and sucrose. Alkylene oxides used
preferably comprise ethylene oxide and propylene oxide, in
particular propylene oxide.
[0040] The reaction mixtures of the invention preferably comprise
compounds having hydrophobic groups. These particularly preferably
involve hydroxy-functionalized compounds having hydrophobic groups.
These compounds having hydrophobic groups have hydrocarbon groups
preferably having more than 6, particularly preferably more than 8
and less than 200, and in particular more than 10 and less than
100, carbon atoms. The compounds having hydrophobic groups can be
used as a separate component or as a constituent of one of
components a) to e), for the production of the reaction mixture.
The hydroxy-functionalized hydrophobic compounds preferably involve
compounds which comply with the definition of the relatively
high-molecular-weight compounds b) having at least two hydrogen
atoms reactive toward isocyanates. Component b) here can comprise
hydroxy-functionalized hydrophobic compounds or can preferably be
composed thereof.
[0041] The hydroxy-functionalized hydrophobic compound used
preferably comprises a hydroxy-functionalized compound known from
oleochemistry, or a polyol known from oleochemistry.
[0042] A number of hydroxy-functional compounds that can be used
are known in oleochemistry. Examples are castor oil, oils modified
using hydroxy groups, e.g. grapeseed oil, black cumin oil, pumpkin
seed oil, borage seed oil, soybean oil, wheatgerm oil, rapeseed
oil, sunflower oil, peanut oil, apricot seed oil, pistachio oil,
almond oil, olive oil, macadamia nut oil, avocado oil, sea
buckthorn oil, sesame oil, hazelnut oil, evening primrose oil, wild
rose oil, hemp oil, thistle oil, walnut oil, fatty acid esters
modified using hydroxy groups and based on myristoleic acid,
palmitoleic acid, oleic acid, vaccenic acid, petroselinic acid,
gadoleic acid, erucic acid, nervonic acid, linoleic acid, linolenic
acid, stearidonic acid, arachidonic acid, timnodonic acid,
clupanodonic acid, or cervonic acid. It is preferable here to use
castor oil and its reaction products with alkylene oxides or with
ketone-formaldehyde resins. The last-named compounds are marketed
by way of example by Bayer AG as Desmophen.RTM. 1150.
[0043] Another group of polyols which are known in oleochemistry
and whose use is preferred can be obtained via ring-opening of
epoxidized fatty acid esters with simultaneous reaction with
alcohols and, if need be, subsequent further transesterification
reactions. Incorporation of hydroxy groups into oils and fats
occurs primarily via epoxidization of the olefinic double bond
comprised in these products, followed by reaction of the resultant
epoxy groups with a mono- or polyhydric alcohol. The product here
of the epoxy ring is a hydroxy group or, in the case of polyhydric
alcohols, a structure having a relatively high number of OH groups.
Since oils and fats are mostly glycerol esters, parallel
transesterification reactions proceed with the abovementioned
reactions. The molar mass of the resultant compounds is preferably
in the range from 500 to 1500 g/mol. These products are supplied by
way of example by Henkel.
[0044] In one particularly preferred embodiment of the inventive
process, the relatively high-molecular-weight compound b) having at
least two hydrogen atoms reactive toward isocyanate comprises at
least one polyol known in oleochemistry and at least one
phenol-modified aromatic hydrocarbon resin, in particular one
indene-coumarone resin. Polyurethane reaction mixtures based on
said component b) have a level of hydrophobic properties which is
sufficiently high that in principle they can even be hardened under
water, or installed during rainfall.
[0045] The phenol-modified aromatic hydrocarbon resin used having a
terminal phenol group preferably comprises phenol-modified
indene-coumarone resins, and particularly preferably industrial
mixtures of aromatic hydrocarbon resins. These products are
commercially available and are supplied by way of example by
Rutgers VFT AG as NOVARES.RTM..
[0046] The OH content of the phenol-modified aromatic hydrocarbon
resins, in particular the phenol-modified indene-coumarone resins,
is mostly from 0.5 to 5.0% by weight.
[0047] The polyol known from oleochemistry and the phenol-modified
aromatic hydrocarbon resin, in particular the indene-coumarone
resin, are preferably used in a ratio by weight of from 100:1 to
100:50.
[0048] Production of an inventive polyurethane reaction mixture can
use a chain extender c). However, the chain extender c) can also be
omitted here. However, the addition of chain extenders,
crosslinking agents, or else, if desired, a mixture of these can
prove successful for modification of mechanical properties, e.g.
hardness.
[0049] If low-molecular-weight chain extenders and/or crosslinking
agents c) are used, the production of polyurethanes can use known
chain extenders. These are preferably low-molecular-weight
compounds having groups reactive toward isocyanates whose molar
mass is from 62 to 400 g/mol, examples being glycerol,
trimethylolpropane, known glycol derivatives, butanediol, and
diamines. Other possible low-molecular-weight chain extenders
and/or crosslinking agents are given by way of example in
"Kunststoffhandbuch, Band 7, Polyurethane" [Plastics Handbook,
volume 7, Polyurethanes], Carl Hanser Verlag, 3rd edition 1993,
chapter 3.2 and 3.3.2.
[0050] The polyurethanes used can in principle be produced without
the presence of catalysts d). Catalysts d) can be used
concomitantly to improve hardening. The catalysts d) selected
should preferably be those that maximize reaction time. It is thus
possible that the polyurethane reaction mixture remains liquid for
a long period. These catalysts are known to the person skilled in
the art. It is also possible in principle, as described, to work
entirely without catalyst.
[0051] Other conventional constituents can be added to the
polyurethane reaction mixture, examples being conventional
additives e). These comprise by way of example conventional
fillers. The fillers used are preferably the conventional, organic
and inorganic fillers, reinforcing agents, and weighting agents
known per se. Individual examples that may be mentioned are:
inorganic fillers, such as silicatic minerals, e.g.
phyllosilicates, such as antigorite, serpentine, hornblendes,
amphiboles, chrysotile, metal oxides, such as kaolin, aluminum
oxides, titanium oxides, and iron oxides, metal salts, such as
chalk, barite, and inorganic pigments, such as cadmium sulfide,
zinc sulfide, and also glass. It is preferable to use kaolin (China
clay), aluminum silicate, and coprecipitates composed of barium
sulfate and aluminum silicate, and also natural and synthetic
fibrous minerals, such as wollastonite, metal fibers of various
lengths, and in particular glass fibers of various lengths, which
may, if desired, have been coated with a size. Examples of organic
fillers that can be used are: carbon black, melamine, rosin,
cyclopentadienyl resins, and graft polymers, and also cellulose
fibers, polyamide fibers, polyacrylonitrile fibers, polyurethane
fibers, polyester fibers based on aromatic and/or aliphatic
dicarboxylic esters, and in particular carbon fibers.
[0052] If the abovementioned inorganic fillers are used as
additives e), their mineral substance constitution preferably
differs from that of the mineral material, and they are ignored
when determining the grain size distribution of the mineral
material.
[0053] The inorganic and organic fillers can be used individually
or in the form of a mixture, and their amounts comprised in the
reaction mixture are preferably from 0.5 to 50% by weight,
particularly preferably from 1 to 40% by weight, based on the
weight of components a) to e).
[0054] The polyurethane reaction mixture should also comprise
dryers, such as zeolites. These are preferably added, prior to
production of the inventive reaction mixture, to the compounds b)
having at least two hydrogen atoms reactive toward isocyanate, or
to the component which comprises the compounds b) having at least
two hydrogen atoms reactive toward isocyanate. Addition of the
dryers avoids any increase in the concentration of water in the
components or in the reaction mixture, and thus avoids formation of
foamed polyurethane. Additions preferred for water adsorption are
aluminosilicates, selected from the group of the sodium
aluminosilicates, potassium aluminosilicates, calcium
aluminosilicates, cesium aluminosilicates, barium aluminosilicates,
magnesium aluminosilicates, strontium aluminosilicates, sodium
aluminophosphates, potassium aluminophosphates, calcium
aluminophosphates, and mixtures thereof. It is particularly
preferable to use mixtures of sodium aluminosilicates, potassium
aluminosilicates, and calcium aluminosilicates in castor oil as
carrier substance.
[0055] To improve the long-term stability of the inventive top
layers, it is moreover advantageous to add agents to counter attack
by microorganisms. Addition of UV stabilizers is also advantageous,
in order to avoid embrittlement of the moldings. These additives
are known, and examples are given in "Kunststoffhandbuch, Band 7,
Polyurethane" [Plastics Handbook, volume 7, Polyurethanes], Carl
Hanser Verlag, 3rd edition 1993, chapter 3.4.
[0056] It is preferable that the components c), d), and e) are
added to the compounds having at least two hydrogen atoms reactive
toward isocyanate groups. This blend is often referred to in
industry as polyol component.
[0057] The ratio in which the isocyanates are combined with the
compounds having at least two hydrogen atoms reactive toward
isocyanate groups should preferably be such that a stoichiometric
excess of isocyanate groups is present.
[0058] In one preferred embodiment of the invention, polyurethane
reaction mixtures are used which lead to hydrophobic, substantially
compact polyurethanes. A polyurethane is termed compact
polyurethane if it is substantially free from gas inclusions. The
density of a compact polyurethane is preferably greater than 0.8
g/cm.sup.3, particularly preferably greater than 0.9 g/cm.sup.3,
and in particular greater than 1.0 g/cm.sup.3.
[0059] Examples of materials that can be used as further additions
are those which inhibit run-off of the binder from the mineral
material. Examples of additions of this type that can be added are
organic fibers, such as cellulose fibers. It is moreover possible
to add polymers which are nowadays used in the bitumen-based
systems used. These are especially neoprenes,
styrene-butadiene-styrene, block copolymers, or a mixture of these,
or else any of the other known rubbers or a mixture of these. The
additions can either be added directly to the mineral mixture in
the form of powder or granules, or else can be dispersed in one of
the polyurethane components.
[0060] There is no restriction on the production of mixtures of the
invention, comprising ground road surfacing, mineral material, and
a polymer reaction mixture, and also, if used, further additions.
They can by way of example be produced in mixers into which the
ground road surfacing and the mineral material is introduced, and
the starting components for the production of the polyurethane
reaction mixture are introduced, for example by spraying. Additions
to be added here, if desired, are preferably added to the mixture
at the respective advantageous juncture. By way of example,
therefore, these may be in solution or dispersion in one of the
components of the reaction mixture, for example in one of
components a) to e), and may be added with these to the mixture.
The additions can also be separately added to the mixture. By way
of example, cellulose fibers can be added at a juncture such that
these are present in homogeneous dispersion in the mixture for the
production of top layers, but are not irreversibly damaged by the
mixing procedure. The inventive mixture here can by way of example
be produced by the process described in DE 196 32 638. It is
likewise possible, for example, to begin by producing the
polyurethane reaction mixture and then to mix this with the mineral
material and, if used, with the further additions. In another
embodiment, the mineral material can, if desired, first be mixed
with some of the components of the reaction mixture, for example
with components b) and, if present, c) to e), and then the
components not yet present, for example component a), can be added
in a mixer. The mixture of the invention, comprising ground road
surfacing, can be produced by a mobile method at the installation
site. Transport to a central plant is not necessary.
[0061] The hydrophobic polyurethane reaction mixtures whose use is
preferred feature particularly good processability. By way of
example, said polyurethane reaction mixtures, and the polyurethanes
obtained therefrom, feature particularly good adhesion. Because of
the hydrophobic nature of the system, the polyurethane reaction
mixture hardens despite the presence of water, e.g. rain, to give a
practically compact product.
[0062] When the mixture of the invention is applied to the
substrate material, it is not necessary that the substrate material
is dry. Surprisingly, even when substrate material is wet, good
adhesion is obtained between the load-bearing layer or the top
layer and the substrate material.
[0063] The mixture of the invention here preferably comprises from
1 to 20% by weight, particularly preferably from 2 to 15% by
weight, and in particular from 4 to 10% by weight, of polymer
reaction mixture, based on the total weight of the mixture of the
invention, comprising ground road surfacing, mineral material, and
a polymer reaction mixture, and also, if desired, further
additions.
[0064] The bond between mineral material and binder of the
invention is very strong. Furthermore, particularly if
hydroxy-functional compounds having hydrophobic groups are used,
there is practically no hydrolytic degradation of the
polyurethanes, and the durability of the top layers produced by the
process of the invention is therefore very high. Top layers of the
invention have particularly good load-bearing properties and are
therefore suitable for all roads, tracks, and areas used by
traffic, particularly for runways and for roads subject to
relatively high loads in construction class V to I, particular III
to I, and runways, where roads of construction class V are access
roads, and roads of construction class I are motorways and
highways. The mineral material used here preferably comprises the
materials recommended for the respective construction class.
[0065] Surprisingly, and particularly when hydrophobic reaction
mixtures are used, there is very little frost damage. A further
advantage of top layers of the invention is low repair cost. It is
sufficient, for example, that the mixture for the production of a
top layer is produced, without heating, in small amounts in situ,
and is applied to the damaged site and compacted. Furthermore, the
mechanical properties of the top layers of the invention do not
change over a period of a number of years. A further advantage of
top layers of the invention is improved wet slip resistance, in
particular in the case of top layers with high polyurethane content
in comparison with top layers with high bitumen content.
[0066] It is preferable that the mixture comprising ground road
surfacing, mineral material, and a polymer reaction mixture, and
also, if desired, further additions is compacted after application
to a substrate material. The intensity of compaction here depends
on the desired application, by way of example, only a little
compaction is used for the production of drainable asphalt, which
can dissipate moisture, but a higher degree of compaction is used
for the production of asphalt that can withstand high loadings. The
degree of compaction needed also depends on the composition of the
rock.
[0067] The process of the invention is preferably used for the
renovation of roads. The ground road surfacing here is preferably
obtained directly at the usage location by surface grinding to
remove material from the road requiring renovation. The material
obtained by the grinding process is preferably broken, ground,
and/or sieved, in order to obtain a preferred grain size
distribution. This recycling material is mixed with binder and with
further mineral material and preferably reinstalled onto the road
in situ, as load-bearing layer or top layer. For this, the
appropriate substrate is preferably pretreated with familiar
adhesion-promoter systems, for example with polyurethane-based
spray adhesives. This serves to give an even greater improvement in
the adhesion between the layers and to compensate any stresses
arising, caused by high loading, for example heavy traffic load or
caused by differences in coefficients of thermal expansion between
substrate and load-bearing layer or top layer. The materials here
are installed using equipment conventional in road construction.
The installation equipment used here preferably has an antiadhesive
coating, or has been wetted with a, preferably biologically based,
release agent. It is preferable that the top layer installed is
then provided with a coating of scattered fine-grain mineral
material (e.g. sand), in order to give an even greater improvement
in the good wet slip properties.
[0068] In comparison with the conventional process in which the new
asphalt is obtained only in stationary asphalt plants, the process
of the invention can save time and energy, by omitting the truck
transport which is otherwise needed. A further feature of inventive
tracks, roads, and areas used by traffic is very high durability,
in particular when subject to frost-thaw cycles, and high
elasticity, and exceptionally high strength. Top layers of the
invention thus combine the favorable properties of bitumen-based
top layers with top layers based on polymer reaction mixtures, e.g.
polyurethanes or epoxides.
[0069] The invention is illustrated by the example below:
Polyurethane Reaction Mixture 1:
[0070] 100 parts by weight of the polyol component of the Elastan
6551/101 system and 50 parts by weight of IsoPMDI 92140, a
formulation comprising diphenylmethane diisocyanate (MDI) were
mixed with one another.
[0071] 10 parts by weight of polyurethane reaction mixture 1 are
mixed with 90 parts by weight of a mixture composed of 90 parts by
weight of mineral mixture (grain size 2/5, Piesberger) and with 10
parts by weight of a broken bitumen-based standard recycling
material from an asphalt top layer, charged to a mold of dimensions
100.times.100.times.100 mm, compacted using 8.5 N/mm.sup.2, and
hardened.
[0072] The compressive strength of the resulting specimen was
determined after more than 24 hours of storage, being 7.0
N/mm.sup.2. This value shows that it is possible to produce top
layers from this type of material.
* * * * *