U.S. patent application number 11/778845 was filed with the patent office on 2008-01-24 for paving joint mortars.
This patent application is currently assigned to National Starch and Chemical Investment Holding Corporation. Invention is credited to LUKAS HUWILER, SIEGMUND KSIAZEK STADTBAUMER.
Application Number | 20080019773 11/778845 |
Document ID | / |
Family ID | 36999933 |
Filed Date | 2008-01-24 |
United States Patent
Application |
20080019773 |
Kind Code |
A1 |
STADTBAUMER; SIEGMUND KSIAZEK ;
et al. |
January 24, 2008 |
PAVING JOINT MORTARS
Abstract
Polymer powders redispersible in water in paving joint mortars,
the paving jointing mortar having approximately 0.5% by weight or
more, based on the paving joint dry mortar, of one or more mineral
binders, as well as one or more additives and, if necessary,
further components. The paving joint mortar can be introduced into
a joint in powder form and subsequently watered, or the paving
joint mortar can be mixed with water before introduction into the
joint and added to the joint in paste form.
Inventors: |
STADTBAUMER; SIEGMUND KSIAZEK;
(Neuenkirch, CH) ; HUWILER; LUKAS; (Neuenkirch,
CH) |
Correspondence
Address: |
NATIONAL STARCH AND CHEMICAL COMPANY
P.O. BOX 6500
BRIDGEWATER
NJ
08807-3300
US
|
Assignee: |
National Starch and Chemical
Investment Holding Corporation
New Castle
DE
|
Family ID: |
36999933 |
Appl. No.: |
11/778845 |
Filed: |
July 17, 2007 |
Current U.S.
Class: |
404/67 |
Current CPC
Class: |
C04B 40/0675 20130101;
C04B 24/26 20130101; C04B 40/0035 20130101; E01C 5/003 20130101;
C04B 28/02 20130101; C04B 40/0675 20130101; C04B 28/02 20130101;
C04B 2111/00672 20130101 |
Class at
Publication: |
404/67 |
International
Class: |
E01C 11/02 20060101
E01C011/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 24, 2006 |
EP |
06015384.8 |
Claims
1. Paving joint mortar comprising: one or more mineral binders in
an amount of about 0.5% by weight or more, based on total dry
weight of the paving joint mortar, one or more additives, and one
or more polymer powders redispersible in water, wherein the paving
joint dry mortar can be added into a joint in powder form and
subsequently watered or mixed with water before introducing the
mortar into the joint in paste form.
2. Paving joint mortar according to claim 1 wherein the one or more
mineral binders are present in an amount of approximately 0.5 to
30% by weight, the one or more additives are present in an amount
of approximately 30 to 99% by weight, and the one or more polymer
powders redispersible in water are present in an amount of
approximately 0.5 to 20% by weight, all based on total dry weight
of the paving joint mortar.
3. Paving joint mortar according to claim 2 wherein the one or more
mineral binders are present in an amount of approximately 1.0 to
20% by weight, the one or more additives are present in an amount
of approximately 50 to 98% by weight the one or more polymer
powders redispersible in water are present in an amount of
approximately 1.0 to 15% by weight, all based on total dry weight
of the paving joint mortar.
4. Paving joint mortar according to claim 1 wherein the one or more
polymer powders redispersible in water comprises one or more
emulsion polymers, suspension polymers, microemulsion polymers
and/or inverse emulsion polymers, each of which have been obtained
by drying.
5. Paving joint mortar according to claim 4 wherein that the
emulsion polymer, suspension polymer, micro-emulsion polymer and/or
inverse emulsion polymer is stabilized with one or more high
molecular compounds
6. Paving joint mortar according to claim 5 wherein that the
emulsion polymer, suspension polymer, micro-emulsion polymer and/or
inverse emulsion polymer is stabilized with one or more protective
colloids and/or with an ionic polymer obtained via radical
(co)polymerisation of olefinic monomers in water wherein at least
part of the olefinic monomers contains an ionic group.
7. Paving joint mortar according to claim 1 wherein the one or more
polymer powders redispersible in water comprises at least one
polymer based on vinyl acetate, ethylene-vinyl acetate,
ethylene-vinyl acetate-vinyl versatate, ethylene-vinyl
acetate-vinyl chloride, ethylene-vinyl chloride, vinyl
acetate-vinyl versatate, ethylene-vinyl acetate(meth)acrylate,
vinyl acetate-vinyl versatate (meth)acrylate, (meth)acrylate,
styrene-acrylate, and/or styrene butadiene, wherein vinyl versatate
is a C.sub.4- to C.sub.12-vinyl ester, and wherein the at least one
polymer further comprises 0 to 50% by weight of further monomers,
based on total weight of the one or more polymer powders
redispersible in water.
8. Paving joint mortar according to claim 1 further comprising at
least one organic component having functional groups, wherein the
organic component is in the polymer powder redispersible in water
or in the paving jointing dry mortar.
9. Paving joint mortar according to claim 8 the functional groups
of the at least one organic component further comprise alkoxysilane
groups, glycidyl groups, epihalohydrin groups, carboxyl groups,
amine groups, hydroxyl groups, ammonium groups, ketone groups, acid
anhydride groups, acetoacetonate groups and/or sulfonic acid
groups.
10. Paving joint mortar according to claim 1 wherein the water is
added in the form of a spray mist and/or surface watering.
11. Paving joint mortar according to claim 10 wherein the water is
added by a lawn sprinkler, water sprinkler, a garden hose with or
without distributor nozzle, and/or a watering can.
12. Paving joint mortar according to claim 1 wherein the one or
more mineral binders are chosen from a hydraulically binding
binder, a latent hydraulic binder, and/or a non-hydraulic binder
which reacts under the influence of air and water.
13. Paving joint mortar according to claim 12 wherein the
hydraulically binding binder is at least cement; the latent
hydraulic binder is chosen from acidic blast furnace slag,
pozzolans and/or metakaolin, and/or a non-hydraulic binder which
reacts under the influence of air and water; and the non-hydraulic
binder is chosen from calcium hydroxide and/or calcium oxide.
14. Paving joint mortar according to claim 1 further comprising
components chosen from colour pigments, cellulose ethers, cellulose
fibres, water-soluble polymers, in particular polyvinyl alcohol,
thickening agents, water retention agents, starch ethers, guar
ethers, wetting agents, polycarboxylates, polyacrylamides,
hydrophobing agents, air pocket formers, biocides, herbicides,
fungicides, defoaming agents, fragrances for keeping away animals,
additives for reducing efflorescence, sedimentation and/or
separation, setting and solidification accelerators, setting
retarders and/or powders which have an alkaline reaction with
water.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of European Application
No. 06 015 384.8, filed 24 Jul. 2006.
[0002] The present invention relates to paving joint mortars. More
particularly, the present invention relates to polymer powders
redispersible in water and their use in paving jointing mortars
containing mineral binders.
[0003] Paving joint mortar is understood by one skilled in the art
as joint mortar commonly used in the open air for jointing paving
stones, natural stones and natural stone slabs, concrete stone
slabs and concrete paving stones, mosaic flooring and mosaic
paving, composite stone, natural stone paving, paving flag, large
stone paving and small stone paving, cobble stone paving, erratic
block paving, wooden paving and decking as well as cement clinker
paving, among others. Such paving is used, for example, for
pedestrian areas, roads, foot paths, cycling paths, access ways,
gutters, and parking areas, as well as in garden architecture. The
paving is introduced predominantly by garden designers and road
builders by way of a so-called "loose construction method", which
is the most commonly used and one of the oldest methods of
construction for such surfacing. In this method, the stones to be
laid are placed onto a loose bed of chippings, sand or granules and
subsequently jointed. The joint width may range, for example, from
a few millimeters to a few centimeters. This type of construction
responds to static or dynamic stresses by elastic deformation.
Thermal impact is eliminated by unhindered deformation without
stresses occurring. The paving cover remains basically permeable to
water. It is generally perceived as a disadvantage in that the
jointing material can be washed out from the joint or sucked up,
for example, by sweeping machines. As a consequence, the stones may
lose their hold. In addition, weeds can grow in these joints in the
case of sparse traffic, something that is often perceived as
undesirable, particularly in the case of natural stone
surfaces.
[0004] Sand is the most commonly used jointing material, and can be
introduced in powder form, for example, by means of a broom. It
adapts without problem to the movement of the slabs and to the
subgrade. An embodiment based on this is described in EP 1 484 295
A1, wherein a small portion of fibrous substances is mixed with the
sand. Still, in this type of construction the above mentioned
disadvantages of the state of the art persist.
[0005] In DE 44 21 970 A1 a jointing material and its use for
jointing natural stone or synthetic stone paving is described. The
jointing material includes a mixture of quartz sand with an
addition of silica dust and a liquid polymer binder. The binder is
typically composed of a mixture of polybutadiene, boiled linseed
oil and isoparaffinic hydrocarbon mixtures. This mixture is swept
with a broom as a soil-moist mass into the dry joints, compacted
with a vibrating plate, and subsequently scraped off with a rubber
scraper. This type of jointing material is consequently
time-consuming to produce and apply. Moreover, such systems can
have low strength levels.
[0006] DE 102 49 636 A1 describes a similar approach. Here,
functionalised polymer powders redispersible in water are mixed
with jointing sand. The polymer powders self-crosslink in acidic or
slightly alkaline medium, resulting in permanent compaction of the
joint filling compound. Water permeability of the moulded body
produced is improved by using the crosslinking polymer powder. The
636 publication does not describe how the jointing sand and the
polymer powder are mixed and introduced into the joints. Strengths,
such as tensile strength in bending and compressive strength, are
not indicated. Conventional, non-crosslinking polymer powders
cannot be used. Moreover, required conditions such as the pH-range
must be accurately maintained in order to guarantee
cross-linking.
[0007] In another approach, sand is mixed with approximately 20 to
40% by weight of cement and other additives, for example, cellulose
fibers, in order to increase durability and strength. As a result,
the paving joints become more durable and washable. Also, nothing
will grow in them. As a result of the high rigidity of the joints,
such joint filling materials are suitable only for a `bound` method
of construction where paving stones are laid onto a rigid subgrade
such as a concrete slab. This subgrade or support layer underneath
the paving must be produced in a manner particularly resistant to
deformation using appropriate materials and requires accurate
planning. Still, stresses frequently occur, which may be due to
changes in temperature. This frequently causes cracks and joints to
loosen, resulting in the stones becoming detached. For this reason,
two-component (2K) jointing mortars based on resin are very
frequently used for this bound method of construction. These
mortars do not respond in an elastic manner to stress, but rather
in a rigid manner comparable to concrete surfaces. However, such
systems are expensive, complicated to apply, and cannot be used for
a non-bound method of construction.
[0008] JP 2285103 describes the use of silica sand and rubber
powder as aggregates, a styrene acrylate copolymer dispersion, and
Portland cement as binders. The joint filling material is first
sprayed and then the joints are filled with it. After filling, the
surface then has to be sprayed with a cleaning agent and cleaned
with a polishing machine. This jointing material consists of two
components and therefore needs to be thoroughly mixed by stirring,
meaning additional effort is required. Moreover, the subsequent
cleaning process is time consuming to execute.
[0009] In order to produce a single component mortar that has been
improved with a polymer, polyvinyl alcohol in powder form can be
added to a paving joint dry mortar with approximately 2 to 7% by
weight of cement. The paving joint dry mortar scattered into the
joint is then wetted with water from the outside. Although this is
simple to handle, the water cannot penetrate into the deeper layers
due to the polyvinyl alcohol swelling rapidly on contact with
water, resulting in an uneven and unsatisfactory introduction of
water into the mortar. Moreover, polyvinyl alcohol provides a
greasy consistency and tends to easily form foam. During continued
contact with water, polyvinyl alcohol is also washed out over time,
which may result in embrittlement of the paving joint.
[0010] In one embodiment, the present invention provides a single
component paving jointing dry mortar in powder form for the loose
method of construction. The mortar is simple to handle and apply.
The applied mortar exhibits an increased durability, certain
flexibility, as well as a corresponding compressive and tensile
strength in bending. Moreover, the paving joint mortar possesses
good flank adhesion, that is, a good adhesion to the paving stone
that is resistant to mechanical stresses such as those caused by
sweeping machines, high pressure cleaning machines, and/or driving
rain. It also provides for easy removal by washing of contamination
from paving jointing mortar residues on the paving stones, thereby
simplifying subsequent cleaning considerably.
[0011] In another embodiment the present invention provides paving
joint mortars having polymer powders redispersible in water. The
paving joint mortar can also having one or more mineral binders in
an amount of about 0.5% by weight or more, based on the desired
paving jointing dry mortar, as well as one or more additives and,
optionally, further components. The paving joint mortar can be
introduced into a joint in powder form and subsequently watered, or
it can be mixed with water before introduction and added to the
joint in paste form.
[0012] In one aspect, paving joint mortars having the polymer
powder redispersible in water can have one or more mineral binders
in about 0.5 to about 30% by weight. In another aspect, the one or
more mineral binders are present in an amount of about 1.0 to about
20% by weight. In even another aspect, the binders are present in
an amount of about 1 to about 10% by weight. In another aspect the
binders are present in an amount of about 1 to about 5% by weight.
In one embodiment, the amount of additives in the paving joint
mortars is about 30 to about 99% by weight. In another aspect, the
amount of additives is about 50 to about 98% by weight. In even
another aspect, the amount of additives is about 60 to about 95% by
weight. In a further aspect, the amount of additives is about 70 to
90% by weight. In one embodiment, the amount of polymer powder
redispersible in water present in the paving joint mortar is about
0.5 to about 20% by weight. In another aspect, the amount of
polymer powder is present in an amount of about 1.0 to about 15% by
weight. In a further aspect, the amount of polymer powder is
present in an amount of about 0.5 to about 10% by weight. In
another aspect, the amount of polymer powder is present in an
amount of about 2 to about 7% by weight. Other optional components
can be present in the paving joint mortar in an amount of about 0
to about 25% by weight. In one aspect, other components are present
in an amount of about 0 to about 20% by weight, based on the paving
jointing dry mortar, respectively.
[0013] Suitable mineral binders include at least (a) hydraulically
binding binders such as cement, (b) latent hydraulic binders such
as acidic blast-furnace slag, pozzolans and/or metakaolin, and/or
(c) non-hydraulic binders that react under the influence of air and
water, such as calcium hydroxide and/or calcium oxide.
[0014] In one embodiment, cement such as Portland cement (e.g.,
according to EN 196 CEM I, II, III, IV and V), calcium sulfate in
the form of .alpha.-hemihydrate and/or .beta.-hemihydrate and/or
anhydrite and/or alumina melt cement can be the hydraulically
binding binder. Pozzolans such as metakaolin, calcium metasilicate
and/or volcanic slag, volcanic tuff, trass, fly ash, blast furnace
slag and/or silica dust can also be used as a latent hydraulic
binder, which, together with a source of calcium such as calcium
hydroxide and/or cement, reacts hydraulically. Lime in the form of
calcium hydroxide and/or calcium oxide, for example, can be used as
non-hydraulic binder reacting under the influence of air and water.
In one embodiment, the systems are based on Portland cement or a
mixture of Portland cement, alumina melt cement and calcium
sulfate, where latent hydraulic and/or non-hydraulic binder can
optionally be added to either system.
[0015] Examples of suitable additives (sometimes also referred to
as fillers) include quartzitic and/or carbonaceous sands and/or
meals such as quartz sand and/or ground limestone, carbonates,
silicates, chalk, layer silicates and/or precipitated silicic
acids. In addition, light weight fillers such as hollow
microspheres of glass, polymers such as polystyrene spheres,
aluminosilicates, silicon oxide, aluminium silicon oxide, calcium
silicate hydrate, aluminium silicate, magnesium silicate, aluminium
silicate hydrate, calcium aluminium silicate, calcium silicate
hydrate, silicon dioxide and/or aluminium iron magnesium silicate
but also clays such as bentonite can be used. It is also possible
for the fillers and/or light weight fillers to possess a natural or
artificially produced color.
[0016] Polymer powders redispersible in water according to the
invention can contain at least one polymer based on vinyl acetate,
ethylene vinyl acetate, ethylene vinyl acetate vinyl versatate,
ethylene vinyl acetate vinyl chloride, ethylene vinyl chloride,
vinyl acetate vinyl versatate, (meth)acrylate, ethylene vinyl
acetate(meth)acrylate, vinyl acetate vinyl versatate
(meth)acrylate, vinyl acetate maleic acid and vinyl acetate maleic
acid ester, vinyl acetate vinyl versatate maleic acid and vinyl
acetate vinyl versatate maleic acid ester, vinyl acetate
(meth)acrylate maleic acid and vinyl acetate(meth)acrylate maleic
acid ester, styrene acrylate and/or styrene butadiene, wherein
vinyl versatate is a C.sub.4- to C.sub.12-vinyl ester. The polymer
powders can also contain about 0 to about 50% by weight of
additional monomers such as monomers with functional groups. In
another aspect, the polymers can contain about 0 to about 30% by
weight of additional monomers. In even another aspect, the polymers
can contain about 0 to about 10% by weight of additional
monomers.
[0017] Polymer powders redispersible in water according to the
invention can be based on one or several polymers. These polymers
can be produced, for example, by emulsion polymerisation,
suspension polymerisation, microemulsion polymerisation and/or
inverse emulsion polymerisation. If necessary, the polymers can
also exhibit a heterogeneous morphology obtained by selecting the
monomer and the production process. Subsequent drying takes place,
for example, by spray drying, freeze drying, fluid bed drying,
roller drying and/or rapid drying. In one embodiment the polymer
powders are produced by emulsion polymerisation and spray
drying.
[0018] Examples of suitable classes of monomers for producing these
polymers include linear or branched C.sub.1- to C.sub.20-vinyl
ester, ethylene, propylene, vinyl chloride, (meth)acrylic acid and
their linear or branched C.sub.1- to C.sub.20-alkyl esters,
(meth)acrylamide and (meth)acrylamide with N-substituted linear or
branched C.sub.1- to C.sub.20-alkyl groups, acrylonitrile, styrene,
styrene derivatives and/or dienes such as 1,3-butadiene. In one
embodiment, the vinyl esters are linear or branched C.sub.1- to
C.sub.12-vinyl esters such as vinyl acetate, vinyl stearate, vinyl
formate, vinyl propionate, vinyl butyrate, vinyl pivalate, vinyl
laurate, vinyl-2-ethyl hexanoate, 1-methyl vinyl acetate and/or
C.sub.9-, C.sub.10- and/or C.sub.11-vinyl versatate, vinyl
pyrrolidone, N-vinyl formamide, N-vinyl acetamide, as well as vinyl
esters of benzoic acid and p-tert.-butyl benzoic acid. In another
embodiment, the vinyl esters are vinyl acetate, vinyl laurate
and/or vinyl versatate. Examples of C.sub.1- to C.sub.12-alkyl
groups of (meth)acrylic acid esters and N-substituted
(meth)acrylamides include methyl groups, ethyl groups, propyl
groups, n-butyl groups, i-butyl groups, tert.-butyl groups, hexyl
groups, cyclohexyl groups, 2-ethyl hexyl groups, lauryl groups,
stearyl groups, norbornyl groups, polyalkylene oxide groups and/or
polyalkylene glycol groups. In one embodiment, the alkyl groups are
methyl groups, butyl groups, and/or 2-ethyl hexyl groups. In
another embodiment, the alkyl groups are methyl methacrylate,
n-butyl acrylate, tert.-butyl methacrylate and/or 2-ethyl hexyl
methacrylate.
[0019] Additional monomers such as monomers with functional groups
can be incorporated by polymerization. For example, it is possible
to copolymerize maleic anhydride, unsaturated dicarboxylic acids
and their branched or linear C.sub.1- to C.sub.20-esters, such as
itaconic acid, maleic acid and/or fumaric acid as well as their
esters, multiply ethylenically unsaturated copolymers such as e.g.
divinyl adipate, diallyl maleate, allyl methacrylate or triallyl
cyanurate, divinyl benzene, butane diol-1,4-dimethacrylate,
triethylene glycol dimethacrylate, hexane diol diacrylate,
functional vinyl monomers and/or (meth)acrylate monomers containing
alcoxy silane groups, glycidyl groups, epihalohydrin groups,
carboxyl groups, amine groups, hydroxyl groups, ammonium groups
and/or sulfonic acid groups. In one aspect the functional monomers
can be hydroxyl propyl(meth)acrylate, N-methylol allyl carbamate,
methyl acrylamidoglycolic acid methyl ester, N-methylol
(meth)acrylamide, vinyl sulfonic acid, acrylamido glycolic acid,
glycidyl(meth)acrylate, 2-acrylamido-2-methyl propane sulfonic
acid, (meth)acryloxypropyl tri(alkoxy)silane, vinyl
trialkoxysilane, vinyl methyl dialkoxysilanes; methoxy groups,
ethoxy groups and/or iso-propoxy groups being used as alkoxy
groups; acetyl acetoxyethyl (meth)acrylate, diacetone acrylamide,
acrylamido glycolic acid, methyl acrylamido glycolic acid methyl
ester, alkyl ether, N-methylol (meth)acrylamide, N-methylol allyl
carbamate, esters of N-methylol (meth)acrylamide and of N-methylol
allyl carbamate, N-[3-(dimethyl amino)propyl]methacrylamide,
N-[3-(dimethyl amino)ethyl]meth-acrylamide, N-[3-(trimethyl
ammonium)propyl]methacrylamide chloride and/or
N,N-[3-chloro-2-hydroxypropyl)-3-dimethyl ammonium
propyl](meth)acrylamidc chloride. In one aspect the proportion of
these comonomers is approximately 0 to 30% by weight. In another
aspect, it is approximately 0 to 20% by weight. In even another
aspect it is approximately 0.1 to 10% by weight, based on the total
proportion of monomer. Care should be taken to ensure that the
proportion of free carboxyl groups is not higher than approximately
10% by weight; in another aspect not higher than approximately 5%
by weight; and in even another aspect not higher than approximately
3% by weight.
[0020] Choice of initiator system used for polymerisation is not
restricted. Thus, all known initiator systems can be used.
[0021] In one embodiment the glass transition temperature
("T.sub.g") of the emulsion polymer is within approximately
-60.degree. C. to 80.degree. C. In another embodiment the
temperature is approximately -30.degree. C. to 50.degree. C. In
even another embodiment the temperature is approximately
-20.degree. C. to 40.degree. C.
[0022] The glass transition temperature T.sub.g of the copolymers
produced and consequently the emulsion polymers can be calculated
empirically as well as determined by experiments from the monomers
used. Using the Fox equation (T. G. Fox, Bull. Am. Phy. Soc.
(serli) 1, p. 123 (1956) and ULLMANNS ENZYKLOPADIE DER TECHNISCHEN
CHEMIE, Vol. 19, 4.sup.th Ed., Verlag Chemie, Weinheim, 1980, pp.
17-18), they can be calculated empirically:
1/T.sub.g=x.sub.A/T.sub.gA+x.sub.B/T.sub.gB+ . . .
+x.sub.n/T.sub.gn, with x.sub.A, x.sub.B . . . the mass fractures
of the monomers A, B, . . . used (in % by weight) and T.sub.gA,
T.sub.gB . . . the glass transition temperatures T.sub.g in Kelvin
of the homopolymers of A, B, . . . concerned. These are listed in,
for example, ULLMANNS ENZYKLOPADIE DER TECHNISCHEN CHEMIE, VCH,
Weinheim, Vol. A21 (1992), p. 169. Another possibility for
determining the glass transition temperatures T.sub.g of the
copolymers is experimental determination, for example, by DSC, the
average temperature being used (midpoint temperature according to
ASTM D3418-82).
[0023] Emulsion, suspension, microemulsion and/or inverse emulsion
polymers produced can be stabilised with one or more higher
molecular compounds, such as one or more protective colloids. The
quantity of stabilizing systems used is approximately 1 to 30% by
weight. In another aspect the amount used is approximately 3 to 15%
by weight, based on the proportion of monomer used.
[0024] Typical water-soluble organic polymeric protective colloids
include higher molecular compounds. These include natural compounds
such as polysaccharides, including chemically modified ones,
synthetic higher molecular oligomers and polymers having no or only
a slight ionic character, and/or polymers produced with monomers
having an at least partially anionic character and, e.g., by
radical polymerisation in situ in the aqueous medium. It is also
possible for only one stabilising system to be used or for
different stabilising systems to be combined.
[0025] Useful polysaccharides and their derivatives include
polysaccharides and polysaccharide ethers soluble in cold water
such as cellulose ether, starch ether (amylose and/or amylopectin
and/or their derivatives), guar ether and/or dextrins. It is also
possible to use synthetic polysaccharides such as anionic,
non-ionic or cationic heteropolysaccharides such as xanthan gum or
wellan gum. The polysaccharides can, but need not, be chemically
modified, e.g., with carboxymethyl groups, carboxyethyl groups,
hydroxyethyl groups, hydroxypropyl groups, methyl groups, ethyl
groups, propyl groups and/or long-chain alkyl groups. Further
natural stabilising systems consist of alginates, peptides and/or
proteins such as gelatin, casein and/or soy protein. Examples
include dextrins, starch, starch ether, casein, soy protein,
hydroxyl alkyl cellulose and/or alkyl hydroxyalkyl cellulose.
[0026] Synthetic stabilising systems include one or several
polyvinyl pyrrolidones and/or polyvinyl acetals having molecular
weights of approximately 2000 to 400,000; fully or partially
saponified and/or modified fully or partially saponified polyvinyl
alcohols with a degree of hydrolysis of approximately 70 to 100
mole %, or in another aspect approximately 80 to 98 mole %, and a
viscosity according to Hoppler in a 4% aqueous solution of about 1
to 50 mPas, or in another aspect approximately 3 to 40 mPas
(measured according to DIN 53015 at 20.degree. C.); as well as
melamine formaldehyde sulfonates, naphthalene formaldehyde
sulfonates, block copolymers of propylene oxide and ethylene oxide,
styrene-maleic acid copolymers and/or vinyl ether-maleic acid
copolymers. Higher molecular oligomers may include non-ionic,
anionic, cationic and/or amphoteric emulsifiers such as alkyl
sulfonates, alkyl aryl sulfonates, alkyl sulfates, sulfates of
hydroxyl alkanols, alkyl disulfonates and alkyl aryl disulfonates,
sulfonic fatty acids, sulfates and phosphates of polyethoxylated
alkanols and alkyl phenols, as well as esters of sulfosuccinic
acid, quaternary alkyl ammonium salts, quaternary alkyl phosphonium
salts, polyaddition products such as polyalkoxylates, e.g., adducts
of 5 to 50 mole ethylene oxide and/or propylene oxide per mole of
linear and/or branched C.sub.6- to C.sub.22-alkanols, alkyl
phenols, higher fatty acids, higher fatty acid amines, primary
and/or secondary higher alkyl amines. The alkyl group can be a
linear and/or branched C.sub.6- to C.sub.22-alkyl group in each
case. Synthetic stabilising systems include partially saponified
and/or modified polyvinyl alcohols, it being possible for one or
several polyvinyl alcohols to be used together, if necessary with
small quantities of suitable emulsifiers. Synthetic stabilising
systems her include modified and/or non-modified polyvinyl alcohols
with a degree of hydrolysis of 80 to 98 mole % and a viscosity
according to Hoppler as 4% aqueous solution of 1 to 50 mPas and/or
polyvinyl pyrrolidone.
[0027] According to a specific embodiment, an ionic polymer
obtained by radical (co)polymerisation of olefinic monomers in
water wherein at least part of the olefinic monomers containing an
ionic group is used as the stabilising system. Such systems are
typically obtained in situ, it being possible for (meth)acrylic
acid, monomers with sulfonic acid groups and/or cationic monomers,
for example, to be used as monomers with an ionic group, such as
described in EP-A 1098916 and EP-A 1109838.
[0028] Moreover, polymers containing carboxyl group based on
monocarboxylic and/or dicarboxylic acids or their anhydrides, for
example, polyacrylic acids, can be used as stabilising systems.
However, care should be taken to ensure that the quantity of such a
stabilising system and/or the quantity of polymer powder
re-dispersible in water used is not chosen too large so as not to
influence the hydration of the mineral binders and its processing
in an excessively negative manner.
[0029] A film forming aid and/or a coalescing agent can also be
added to the polymer powders redispersible in water. The amount can
be approximately 0 to 5% by weight, or in another aspect,
approximately 0 to 2% by weight, based on the copolymer
content.
[0030] Polymer powders redispersible in water include those with a
low proportion of organic volatile components (VOC), such as those
possessing a boiling point of less than 250.degree. C. at normal
pressure. These include, for example, non-reacted monomers and
non-polymerisable contaminants contained in the monomers and
by-products of the polymerisation. VOC content of the polymer
powders redispersible in water amounts to less than approximately
5000 ppm, in another aspect less than 2000 ppm, in even another
aspect less than 1000 ppm, and in another aspect less than
approximately 500 ppm, based on polymer content.
[0031] Other components such as additives can be added to the
polymer powders redispersible in water, with their addition
occurring before, during and/or after drying. The types of these
components used are numerous. Liquid components can be added before
or during drying, but can also be sprayed onto the powder
subsequently. Components in powder form can be added during or
after spray drying, but can also be added during dispersion mixing
before the drying step.
[0032] One embodiment includes the addition of at least one further
organic component with functional groups. This can be part of the
polymer powder re-dispersible in water and/or can be mixed with the
paving joint dry mortar as a separate component. If this component
is liquid, it can be added to the polymer powder redispersible in
water during its production or transformed into powder form. When
used in powder form, it can be mixed with the polymer powder
redispersible in water and/or the paving jointing dry mortar.
Useful organic components with functional groups react in an
alkaline medium either with itself and/or other compounds. Examples
of such compounds include crosslinking agents such as epoxides,
epoxy resins, oligoamines and/or polyamines, bifunctional masked
aldehydes with at least 3 carbon atoms, silanes, siloxanes,
isocyanates which can be used together with hydroxy compounds such
as polyols, if necessary, boric acid and/or borax and/or compounds
with carbodiimide groups, carboxyl groups and/or epichlorohydrin
groups.
[0033] Functional groups of these organic components and of the
(co-)polymerisable monomers with functional groups include silane
groups such as alkoxy silane groups, glycidyl groups, epihalohydrin
groups, N-methylol groups, carboxyl groups, amine groups, hydroxyl
groups, ammonium groups, ketone groups, acid anhydride groups,
acetoacetonate groups, sulfonic acid groups, amide groups, amidine
groups, imine groups, ester groups, carboxyl groups, carbonyl
groups, aldehyde groups, sulfate groups, sulfonate groups and/or
thiol groups. In one aspect the functional groups are silane
groups, epoxy groups, epihalohydrin groups and/or amine groups.
[0034] The paving joint mortar can also contain further components
in typical quantities. It is advantageous if they are present in
powder form. If they are by nature liquid, they can be adsorbed
onto a matrix or embedded in a matrix in order to be able to handle
them in powder form. There are no essential limitations regarding
the type of these further components. Non-limiting examples of such
further components are colour pigments, cellulose fibers,
water-soluble polymers, in particular fully or partially saponified
and, if necessary, modified polyvinyl alcohols, polyvinyl
pyrrolidones, polyalkylene oxides and polyalkylene glycols, the
alkylene group typically being a C.sub.2- and/or C.sub.3-group,
which includes also block copolymers, thickening agents, water
retention agents, alkyl hydroxyalkyl ethers and/or alkyl
hydroxyalkyl polysaccharide ethers such as such as cellulose ether,
starch ether and/or guar ether, the alkyl group and hydroxyalkyl
group typically being a C.sub.1- to C.sub.4-group, synthetic
polysaccharides such as anionic, non-ionic or cationic
heteropolysaccharides, in particular xanthan gum or wellan gum,
wetting agents, dispersing agents, cement liquefiers,
polycarboxylates, polycarboxylate ethers, polyacrylamides,
hydrophobing agents such as silanes, silane esters, siloxanes,
silicones, fatty acids and/or fatty acid esters, air pocket
formers, rubber powders, biocides, herbicides, fungicides,
defoaming agents, fragrances for keeping animals away, additives
for reducing sedimentation, segregation and/or efflorescence such
as compounds based on natural resins, in particular rosin and/or
its derivatives, setting and solidification accelerators, setting
retarders and/or powders which have an alkaline reaction with,
water such as oxides and/or hydroxides of alkali salts and/or
alkaline earth salts such as calcium hydroxide, calcium oxide,
sodium hydroxide and/or potassium hydroxide and/or aluminium
hydroxide.
[0035] In principle, all organosilicone compounds can be used as
silanes, silane esters, silicones and/or siloxanes. However, it is
advantageous, though not compelling for the boiling point of the
organosilicon compound used not to be too low at normal pressure,
for example, approximately 100.degree. C. and more. The
organosilicon compounds may be soluble, insoluble or only partially
soluble in water. Useful compounds can have no or only limited
solubility in water. These may consist of silicic acid esters with
the formula Si(OR').sub.4, organoxysilanes with the formula
Si(OR').sub.4-n where n=1 to 3, polysilanes with the formula
R.sub.3Si(SiR.sub.2).sub.nSiR.sub.3 where n=0 to 500 or in another
aspect n=0 to 8, disiloxanes, oligosiloxanes and polysiloxanes of
units with the general formula
R.sub.cH.sub.dSi(OR').sub.e)OH).sub.fO.sub.(4-c-d-e-f)/2 where c=0
to 3, d=0 to 2, e=0 to 3, f=0 to 3 and the sum of c+d+e+f is a
maximum of 3.5 per unit, R' representing identical or different
alkyl radicals or alkoxy alkylene radicals with 1 to 4 C-atoms
(e.g., methyl or ethyl) and R being identical or different and
representing branched or non-branched alkyl radicals with 1 to 22
C-atoms, cycloalkyl radicals with 3 to 10 C-atoms, alkylene
radicals with 2 to 4 C-atoms, aryl radicals, aralkyl radicals,
alkyl aryl radicals with 6 to 18 C-atoms. The above mentioned
radical R can be substituted with halogens such as F or Cl, with
ether groups, thioether groups, ester groups, amide groups, nitrile
groups, hydroxyl groups, amine groups, carboxyl groups, sulfonic
acid groups, carboxylic anhydride groups and carbonyl groups. R can
also have the meaning OR' in the case of polysilanes.
[0036] Further components also include polysaccharide ethers such
as cellulose ether and/or starch ether, hydrophobing agents such as
silanes, silane esters, fatty acids and/or fatty acid esters,
agents for reducing efflorescence, for example, those based on
natural resins, cellulose fibres, defoaming agents and/or
pigments.
[0037] The proportion of these additional components may be very
small, for example, for surface-active substances, based on the
paving jointing dry mortar, and be within the region of
approximately 0.01% by weight or more, in another aspect
approximately 0.1% by weight and more, but should not typically
exceed approximately 2% by weight, in another aspect approximately
1% by weight. On the other hand, the proportion of mixed pigments
can be higher, but should be not more than approximately 25% by
weight, in another aspect not more than approximately 20% by
weight, and in even another aspect not more than approximately 15%
by weight. The proportion of hydrophobing agents is approximately
0.05 to approximately 3% by weight, in another aspect approximately
0.1 to approximately 2% by weight and in even another aspect
approximately 0.2 to approximately 1% by weight. The content of the
other components is between approximately 1% by weight and
approximately 15% by weight, in another aspect between
approximately 2 and approximately 10% by weight, based on the
paving jointing dry mortar.
[0038] As a rule, it is beneficial for the user if the paving
jointing mortar is scattered as paving jointing dry mortar into the
empty joints or swept into them with a broom, and water then
subsequently added, for example, over the surface. Such addition of
water over the surface without subsequent mixing of the mortar is
sufficient to both re-disperse the polymer powder re-dispersible in
water in this compact environment and distribute it in the matrix.
On setting and drying of the paving jointing mortar, a
water-insoluble film is then formed. This thus increases the
cohesion of the set paving jointing mortar.
[0039] When introducing water over the surface, suitable methods
include those in which the paving jointing dry mortar scattered or
swept in is not damaged. For example, this can be accomplished with
a gentle introduction of water in the form of a spray mist and/or
surface watering. The method of water introduction is not
restricted in any way as long as it does not damage the paving
jointing mortar introduced. This can be achieved with a lawn
sprinkler, a water sprinkler, a garden hose with or without
distributor nozzle and/or a watering can. It is advantageous to set
the duration of watering such that the water penetrates through the
entire paving jointing dry mortar, providing the mortar with
sufficient water for hydration down to the subgrade. If too much
water is added, the excess seeps into the subgrade, usually without
negative consequences. If insufficient water is added, only the
upper part of the paving jointing mortar is hydrated. During later
watering, either artificially or by rain or dew, further water can
then diffuse through the mortar set at the surface and penetrate
into deeper layers. However, it is also possible for the water to
pass into the paving jointing dry mortar through the subgrade, thus
causing hydration.
[0040] According to a further embodiment, the paving jointing dry
mortar is first stirred with water and introduced into the joints
as stirred mortar. In the case of this variation, however, it is
helpful to adjust the quantity of water in such a way that the
stirred mortar receives an easily processable consistency in order
to be introduced into the joints without running off.
[0041] Paving jointing mortar containing the polymer powder
re-dispersible in water that can be used according to the invention
typically exhibits a high level of wettability. The polymer powder
re-dispersible in water re-disperses without additional shearing
forces and mixing processes and subsequently forms a
water-insoluble film. Thus, polymer powders re-dispersible in water
results in none or only minor disadvantages vis-a-vis
emulsifier-stabilised dispersions with the physical values of the
set paving jointing mortar, even though these systems have
previously been thoroughly mixed in order to guarantee a
corresponding homogeneity of the mortar. Nevertheless, the end
properties of the paving jointing mortar are entirely comparable in
spite of a much simpler introduction and processing.
[0042] The invention will be explained in further detail by way of
the following examples.
EXAMPLE 1
Production and Watering by Spray Mist of Paving Joint Dry Mortar
Introduced by Scattering
[0043] Mortar prisms were produced in order to investigate the
introduction by scattering and watering of joints under conditions
which are as clearly defined as possible. From this it was possible
to subsequently determine physical values such as the tensile
strength in bending and the compressive strength.
[0044] A paving joint dry mortar was prepared by mixing
homogenously in an agitator 5% by weight of Portland cement CEM I
42.5 N, 87% by weight of quartz sand with a sieve line of 0.063 to
1.5 mm, 3% by weight of a calcium carbonate (Durcal 10) and 5% by
weight of a polymer powder redispersible in water. A comparative
example was carried out using in place of the polymer powder a
partially saponified polyvinyl alcohol with a degree of hydrolysis
of 88 mole % and a viscosity of 4 mPas (according to Hoppler as 4%
aqueous solution, measured according to DIN 53015 at 20.degree. C.)
(in the following tables referred to as "PVOH"). Another
comparative example was carried out entirely without polymer
powder, the omitted polymer quantity being replaced by quartz
sand.
[0045] 500 g of the dry mortar produced were then scattered into a
4 cm.times.4 cm.times.16 cm metal prism mould, the inside wall of
the prism mould having been painted with mould oil as release agent
using a painter's brush. The dry formulation was compacted by
manually shaking and tapping for 10 seconds. The surface of the dry
mortar scattered in was smoothed off with a trowel.
[0046] A spray bottle typically used for spraying plants was used
for watering. The water cone formed during spraying was adjusted so
that the water was sprayed selectively onto the mortar surface from
a distance of 10 cm. The spray duration was 5 to 10 minutes,
depending on how well the surface was wetted and the water was able
to penetrate inside. The necessary quantity of water was determined
by way of a separate test wherein the surface was damaged
periodically using a fine spatula and the depth of water
penetration assessed optically until the water had reached the
lowermost layer of the paving jointing mortar.
[0047] During watering the following assessments were carried out:
(a) wetting of the surface (i.e., how well the water is absorbed by
the joint during the entire watering process), (b) water saturation
(i.e., how much water can be sprayed continually onto the prism
until water floats on the surface), (c) bubble formation (i.e.,
whether bubbles rise to the surface during or immediately after
spraying on of the water, which may have a negative influence of
the surface properties), and (d) cleaning after contamination
(i.e., how simply the prism mould could be cleaned after releasing
the prisms). These assessments provide a good indication regarding
the behavior of the watered paving joint mortar on the surface of
the paving stones.
[0048] 18 hours after completion of the introduction of water, the
prisms were released and stored at 23.degree. C. and a relative
atmospheric humidity of 50% (standard climate).
TABLE-US-00001 TABLE 1 Table 1 indicates the quantities of water
sprayed onto the different paving jointing mortars containing the
polymer powders re-dispersible in water EVA-1, EVA-2 and St/Ac and
the comparative samples PVOH and without polymer powder and
assessment of the different paving stone joints during
watering.sup.a). Without EVA-1 EVA-2 St/Ac PVOH.sup.c) p.p..sup.d)
Quantity of 9 9 9 12 9 water (% by weight) Water 7 7 5 6 None
saturation (% by weight) Wetting of Excellent Excellent Average
Excellent Excellent surface Spray duration 5 5 10 8 5 (min) Bubble
None None None Strong None formation Cleaning after Excellent
Excellent Ex- Smeared Excellent contamination.sup.b) cellent
.sup.a)The polymer powders re-dispersible in water EVA-1, EVA-2 and
St/Ac consist of different spray-dried dispersions stabilised with
polyvinyl alcohol based on ethylene-vinyl acetate (EVA-1 and EVA-2)
copolymers and styrene-acrylate copolymers (St/Ac).
.sup.b)"Excellent" means that cleaning caused no problems
whatsoever and the residues were easily removed by washing.
"Smeared" means that the residual layer could be removed only after
intensive cleaning. .sup.c)PVOH represents partially hydrolysed
polyvinyl alcohol. .sup.d)P.P. represents "polymer powder".
TABLE-US-00002 TABLE 2 Table 2 illustrates the results of repeated
watering of the paving joint mortar in the prism mould at intervals
of one hour. Four prisms were produced per composition, one being
put aside after each watering cycle for removal from the mould
after 18 hours and assessed. The percentage indicated below
provides details of the proportion of prisms which formed a compact
unit and did not disintegrate. Moreover, the surface of the last
prism was assessed after a storage period of 4 days for its surface
hardness and surface hydrophobicity. Quantity of water.sup.d) EVA-1
St/Ac PVOH.sup.c) Without p.p..sup.d) 1 Watering 3 60% 60% 20% 95%
2 Watering 6 95% 70% 70% 100% 3 Watering 9 100% 100% 75% 100% 4
Watering 12 100% 100% 90% 100% Surface hardness.sup.e) Hard Average
Hard Soft Surface hydrophobicity.sup.f) 5 min 30 sec 30 sec 0 sec
.sup.d)Indicated in % by weight. .sup.e)The surface hardness was
assessed by scratching with a pointed metal rod. .sup.f)To assess
the surface hydrophobicity, 1 ml of water was placed drop-wise onto
the surface using a pipette and the time was measured by which all
the water had been absorbed by the subgrade.
[0049] Tables 1 and 2 show, among other things, that paving joint
mortar with partially hydrolysed polyvinyl alcohol exhibits the
greatest water requirement. In contrast to paving jointing mortars
prepared without polymer powder or with polymer powders
redispersible in water (EVA-1, EVA-2 and St/Ac), the paving joint
mortar with PVOH absorbs a relatively large amount of water at its
surface, preventing the water from reaching the underlying layers.
Thus, the mineral binder does not set and the organic binder does
not form a film, resulting in a lack of strength of these
layers.
[0050] Even if wetting of the dry mortar is excellent, the unset
paving jointing mortar may exhibit a moderate hydrophobicity as
shown by the example of EVA-1. This contributes to less dirt
penetrating into the joints and being washed away, particularly in
the case of an inclination and/or fairly strong rain.
TABLE-US-00003 TABLE 3 Tensile strengths in N/mm.sup.2 determined
at different storage periods by bending of the mortar prisms
obtained, in line with EN13892-2. Storage time in a standard
climate EVA-1 EVA-2 St/Ac PVOH.sup.c) Without p.p..sup.d) 1 day
0.07 0.06 0.04 0.22 0.18 3 days 0.56 0.43 0.51 0.97 0.35 7 days
1.67 0.99 1.50 1.80 0.50 14 days 2.07 1.05 1.69 --.sup.g) 0.45 28
days 2.19 0.99 1.57 --.sup.g) 0.40
TABLE-US-00004 TABLE 4 Compressive strength in N/mm.sup.2
determined after different storage periods by bending of the mortar
prisms obtained, in line with EN13892-2. Storage time in a standard
climate EVA-1 EVA-2 St/Ac PVOH.sup.c) Without p.p..sup.d) 1 day
0.20 0.16 0.17 0.16 0.26 3 days 1.24 0.94 1.00 1.28 0.75 7 days
5.52 2.37 3.18 2.99 1.02 14 days 6.15 2.63 3.21 --.sup.g) 0.93 28
days 5.41 2.44 2.98 --.sup.g) 0.77 .sup.g)No values available.
[0051] Tensile strength and compressive strength are excellent
measures for assessing cohesion of the watered paving jointing
mortar. The values given in Tables 3 and 4 clearly show the
additional cohesion achieved by adding polymer powder redispersible
in water versus those containing only mineral binder (indicated by
"without polymer powder"). These high values are highly surprising
since the dry mortar was merely watered without mixing the mortar.
Mixing enhances the redispersion of the polymer powder
redispersible in water, guaranteeing good distribution of the
redispersion achieved. The cohesion achieved is sufficient to
prevent damage, for example, in the case of impact or expert
cleaning with sweeping machines or high pressure cleaners. The
corresponding early strength values additionally provide the paving
jointing mortar applied with sufficient protection against driving
rain and hail. The polymer powder redispersible in water used
provides the paving joint mortar also with a good flank adhesion
such that the joint does not detach itself from the paving stone.
The low proportion of mineral binder guarantees the required
flexibility needed to survive deformations of the subgrade without
cracking. As a result of the controlled optimisation of the types
and quantities of hydraulically binding binder used and of the
polymer powder redispersible in water, it is, moreover, possible to
correspondingly optimize flexibility, tensile strength and
compressive strength, as well as tensile bond strength in line with
users' requirements without having to change processing.
EXAMPLE 2
Stirring of Paving Stone Joint Mortar with Water Before
Application
[0052] The paving joint dry mortar produced according to Example 1
is stirred with water for one minute using a propeller stirrer at
900 rpm, the amount of water adjusted for consistency. During this
process, care was taken in mixing that the resulting mortar was not
too thin but also not too highly viscous, and could be introduced
into a prism box as described in Example 1 by simply using a
trowel. Prior to addition to the box, the mixed paving joint mortar
was allowed to mature for 3 minutes and was then stirred once more
for 15 seconds. Following the introduction of the mortar, the
surface of the mortar was smoothed off with a trowel. The storage
conditions were handled in a manner analogous to Example 1.
[0053] Quantities of water used for adjusting the consistency of
the different samples of EVA-1, St/Ac and the comparative sample
without polymer powder and tensile strength in bending and
compressive strengths after different storage periods, in
N/mm.sup.2, in line with EN13892-2 are illustrated in Table 5
below.
TABLE-US-00005 TABLE 5 Tensile strength in bending Compressive
strength (N/mm.sup.2) (N/mm.sup.2) Storage time in a Without
Without standard climate EVA-1 St/Ac p.p..sup.d) EVA-1 St/Ac
p.p..sup.d) Quantity of water 9.5 9.5 15 9.5 9.5 15 (% by weight) 1
day 0.26 0.30 0.04 0.35 0.49 0.32 3 days 2.13 2.39 0.30 4.11 4.75
0.54 7 days 3.77 3.58 0.10 9.23 7.36 0.74
[0054] Table 5 illustrates that by mixing the paving joint dry
mortar with water prior to introduction into the joints, the
physical values obtained are slightly higher than by introduction
of water over the surface according to Example 1. Consequently, by
using paving joint dry mortar according to the present invention,
the user has the choice of choosing either an extremely simple and
convenient type of application involving dry introduction with
subsequent surface watering, or by externally mixing the paving
joint dry mortar with water and subsequent introduction to obtain
even higher physical strength values.
[0055] Although the present invention has been described and
illustrated in detail, it is to be understood that the same is by
way of illustration and example only, and is not to be taken as a
limitation. The spirit and scope of the present invention are to be
limited only by the terms of any claims presented hereafter.
* * * * *