U.S. patent application number 10/404483 was filed with the patent office on 2003-10-16 for method of applying traffic marking onto an oily road surface and traffic paints formulated therefor.
Invention is credited to Hermes, Ann Robertson, Schall, Donald Craig, Sobczak, Jeffrey Joseph.
Application Number | 20030194486 10/404483 |
Document ID | / |
Family ID | 28454873 |
Filed Date | 2003-10-16 |
United States Patent
Application |
20030194486 |
Kind Code |
A1 |
Hermes, Ann Robertson ; et
al. |
October 16, 2003 |
Method of applying traffic marking onto an oily road surface and
traffic paints formulated therefor
Abstract
A method for applying a traffic marker to road beds consisting
of using a traffic paint which contains a polymer having a low
molecular weight and a Tg of from -25.degree. C. to 25.degree. C.,
wherein the polymer is polymerized from a monomer mixture in which
from 10% to 99.9%, by weight of the total polymer solids, consists
of at least one hydrophobic monomer having a Hansch .pi. value of
at least 3.5. The traffic paint of the present invention readily
adheres to oily road surfaces.
Inventors: |
Hermes, Ann Robertson;
(Ambler, PA) ; Schall, Donald Craig; (Lansdale,
PA) ; Sobczak, Jeffrey Joseph; (Coatesville,
PA) |
Correspondence
Address: |
ROHM AND HAAS COMPANY
PATENT DEPARTMENT
100 INDEPENDENCE MALL WEST
PHILADELPHIA
PA
19106-2399
US
|
Family ID: |
28454873 |
Appl. No.: |
10/404483 |
Filed: |
April 1, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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60371312 |
Apr 10, 2002 |
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Current U.S.
Class: |
427/136 ;
427/137 |
Current CPC
Class: |
C09D 5/004 20130101 |
Class at
Publication: |
427/136 ;
427/137 |
International
Class: |
E01C 005/00 |
Claims
We claim:
1. A method for improving the adhesion of traffic markers on a road
surface comprising applying onto said road surface a layer of an
aqueous traffic paint comprising a low molecular weight polymer
having a Tg of from -25.degree. C. to 25.degree. C., said polymer
polymerized from a monomer mixture containing from 10% to 99.9%, by
weight, based on the total weight of the polymer solids, of at
least one hydrophobic monomer.
2. The method of claim 1 wherein when the Tg of the polymer is from
-25.degree. C. to 25.degree. C., the hydrophobic monomer content of
the polymer is from 10 to 99.9%, by weight, based on the total
weight of the polymer.
3. The method of claim 2 wherein when the Tg of the polymer is from
5.degree. C. to 25.degree. C., the hydrophobic monomer content of
the polymer is from 20 to 99.9%, by weight, based on the total
weight of the polymer.
4. The method of claim 1 further comprising from 0.1% to 50% by
weight, based on the total weight of the polymer, of at least one
vinyl aromatic monomer.
5. The method of claim 1 further comprising contacting said layer
with a drying agent.
6. A method for improving the adhesion of traffic markers on an
oily road surface comprising applying onto said oily road surface a
layer of an aqueous traffic paint comprising a low molecular weight
polymer having a Tg of from -25.degree. C. to 25.degree. C., said
polymer having been polymerized from a monomer mixture containing
from 10% to 99.9%, by weight, based on the total weight of the
polymer solids, of at least one hydrophobic monomer.
7. The method of claim 6 wherein when the Tg of the polymer is from
-25.degree. C. to 25.degree. C., the hydrophobic monomer content of
the polymer is from 10 to 99.9%, by weight, based on the total
weight of the polymer.
8. The method of claim 7 wherein when the Tg of the polymer is from
5.degree. C. to 25.degree. C., the hydrophobic content of the
polymer is from 20 to 99.9%, by weight, based on the total weight
of the polymer.
9. The method of claim 6 further comprising from 0.1% to 50%, by
weight, based on the total weight of the polymer, of at least one
vinyl aromatic monomer.
10. The method of claim 6 further comprising contacting said layer
with a drying agent.
Description
[0001] This invention relates to a method of producing traffic
markings which readily adheres to various substrates associated
with roads and highways. More particularly, the method of the
present invention is useful as a traffic paint which readily
adheres to roadbeds that have an oily surface.
[0002] White and yellow traffic markings used for demarcating
traffic lanes are a common sight on almost all roads. These
markings provide the necessary guidance to ensure safe driving
conditions under varying weather conditions. Within the context of
traffic markings, the term "roads" is more expansive than merely
streets and highways. "Roads" is used herein as a generic term and
it includes any indoor or outdoor solid surface that is or may be
exposed to pedestrians, moving vehicles, tractors or aircraft,
either continuously, continually or intermittently. Some examples
or "roads" include highways, streets, driveways, sidewalks,
runways, taxiing areas, tarmac, parking lots and indoor floors
(such as factory floors or floors inside shopping malls). The
surface materials of "roads" may be masonry, asphalt, resins,
concrete, cement, stone, stucco, tiles, wood, polymeric materials
and any combinations thereof. Also, as used herein, "roads"
embraces any surface of any substrate associated with roads,
including, for example, signs, barricades, medial strips and
traffic signal devices.
[0003] The majority of traffic markings, such as solid, transverse
or interrupted stripes, are paint-based and traditionally include
solvent-borne binders, these being predominantly alkyds and
chlorinated rubber modified alkyds. However, since the early
1980's, environmentally safer paints based on water based solvent
systems began to be employed. These waterborne traffic paints are
primarily based on acrylic emulsions and produce dramatically lower
volatile organic content ("VOC") emissions than traditional
solvent-based traffic paint systems.
[0004] The application of traffic paints is inherently challenging
because the substrate to which the paint is applied is very rarely
of uniform consistency or "clean". Various foreign substances cover
road surfaces either partially or completely. This is especially
the case with respect to existing road surfaces which require
periodic repainting of its traffic markings. Particularly
problematic roads to paint are those where oil is present on the
surface. These may result from deposits produced over a long period
of time by heavy vehicular traffic or, from oil based materials
which may make up the road bed itself. These oily materials may
leach to the surface over time. Within the scope of this invention,
"oily" or "oil contaminated" describes a road surface which may be
either partially or completely covered with oily substances.
[0005] As for oil which might be externally deposited onto a road
surface, it usually comes from oil or grease dropped from vehicles
as they pass over the road surface. Over time, with many vehicles
traveling over the same area of a road, these seemingly tiny
droplets will add up to create a significant oily surface film.
Further, as they age or if poorly maintained, many vehicle engines
will burn increasingly more oil as part of the internal combustion
process. This oil is vaporized and passes out the exhaust system.
Once airborne, the vaporized oil will cool, condense and drop to
the road surface, adding to any oily film already present.
[0006] One source of oil on road surfaces are "patches" which are
used to cover holes or cracks in older roadbeds. Another source of
oil are materials known as "sealers" which are used to resurface an
entire roadbed. An example of such a material is commonly known as
"chip seal", which consists of stone, rocks or sand mixed in or
applied over a layer of asphalt or asphalt based emulsion products.
In some instances, the stone chips are washed in kerosene or such
similar solvent prior to application onto the roadbed. Residual
amounts of these solvents on the stone chips will result in an even
reduced potential for adhesion.
[0007] One attempt to address the issue of coating similar surfaces
is disclosed in EP 0960919 B1. This patent utilizes low molecular
weight, low Tg, hydrophobic polymers to aid in the adhesion of
paints to roofs and other horizontal or vertical construction
surfaces which have been coated with a mastic type material to
inhibit the seepage of water into the structure to which they are
applied. The problem with this method is that it requires the use
of a tiecoat, or primer, before the application of the topcoat.
While the tiecoat may consist of a formulation similar to that of
the topcoat, it requires the presence of a multi-valent metal ion
complex. The requirement of having to add another process step in
the application of the paint and the addition of a metal ion into
the formulation are unacceptable to traffic paint applicators.
Since the application of traffic paints often causes congestion
resulting from having to shut down traffic lanes or reroute traffic
patterns, the less time spent applying the product, the better.
Having to apply a tiecoat before the topcoat adds unacceptable time
to the overall painting process. Further, the addition of metal
ions into a generally outdoor paint opens up the possibility of
exposing the surrounding environment to pollution caused by the
leaching out of the toxic metal ion from the traffic paint over
time.
[0008] The present invention solves the problem of making traffic
paint adhere to an oily roadbed by providing a composition
consisting of a polymer having a low Tg that is generated from a
mixture of monomers, wherein from 10% to 99.9% of these monomers
are hydrophobic. U.S. Pat. No. 6,228,901 B1 discloses polymers
having a higher Tg that are produced from a variety of monomers, at
least some of which are hydrophobic, which impart improved wear
resistance to traffic paint formulations. However, this patent does
not address the issue of providing a traffic paint formulation
which may be successfully applied to road surfaces which are
covered with an oily film.
[0009] In accordance with the present invention, there is provided
a method for improving the adhesion of traffic paint on oily road
surfaces by applying onto the road surface a layer of an aqueous
traffic paint which contains a low molecular weight polymer having
a Tg of from -25.degree. C. to +25.degree. C. that is polymerized
from a monomer mixture containing from 10% to 99.9%, by weight,
based on the total weight of the polymer solids, of at least one
hydrophobic monomer, wherein the relationship between the Tg of the
polymer and the hydrophobic monomer content of the polymer is such
that when the Tg of the polymer is between -25.degree. C. and
25.degree. C., the hydrophobic monomer content may be as low as
10%, up to a maximum of 99.9%. However, when the Tg is on the high
side of this range, that is, between 5.degree. C. and 25.degree.
C., the hydrophobic monomer content of the polymer must be at least
20% up to the maximum of 99.9%.
[0010] Optionally, one or more vinyl aromatic monomers may
represent all or a portion of the hydrophobic monomer content. When
present, the preferred amount of vinyl aromatic monomers is from
0.1 to 50%, based on the total weight of the polymer. If, however,
only a low percentage of vinyl aromatic monomer is used, such as,
for example, 5%, then other hydrophobic monomers must be present in
an amount of at least 5% so that the minimum total percentage of
hydrophobic monomer content is at least 10%.
[0011] The definitions of certain terms used herein is as
follows.
[0012] "Polymer" means a dispersed, solubilized or a sequential
polymer, as defined below.
[0013] "Dispersed polymer" means particles of polymer colloidally
dispersed and stabilized in an aqueous medium.
[0014] "Solubilized polymer" includes "water soluble polymer",
"water reducible polymer" or a mixture thereof. Water soluble
polymer means a polymer dissolved in an aqueous medium. Water
reducible polymer means a polymer dissolved in water and a water
miscible organic solvent, such as, methanol, ethanol and glycol
ethers. Solubilized polymer describes a polymer solution
characterized by having the self-crowding constant (K) of the
Mooney equation equal to zero. By contrast, a dispersed polymer has
K equal to 1.9. The Mooney equation is described in detail in an
article entitled "Physical Characterization of Water Dispersed and
Soluble Acrylic Polymers" by Brendley et al., in "Nonpolluting
Coatings and Coating Processes" published by Plenum Press, 1973,
Gordon and Prane, ed.
[0015] "Sequential polymer" means a polymer which includes
particles containing two or more polymeric phases, such as, for
example, an inner phase, and an outer phase, wherein the outer
phase is the predominant phase in contact with the aqueous medium
in which the particle is dispersed. Some particles containing two
or more polymeric phases include core/shell particles, core/shell
particles with shell phases incompletely encapsulating the core or
core/shell particles with a multiplicity of cores or
interpenetrating network particles.
[0016] Sequential polymers may be prepared by conventional emulsion
polymerization processes, preferably by well-known multi-stage
emulsion polymerization, in which at least two stages differing in
composition are formed in a sequential fashion. Such a process
usually results in the creation of at least two mutually
incompatible polymer compositions, thereby resulting in the
formation of at least two phases. Each stage of the sequential
polymer particles may contain chain transfer agents and
surfactants, as well as other additives necessary to perform the
polymerization reaction. U.S. Pat. No. 4,814,373 may be consulted
for further general and preferred details used for preparing
sequential polymers by emulsion polymerization techniques.
[0017] "Tg" is the "glass transition temperature" of a polymer. The
glass transition temperature is the temperature at which a polymer
transitions from a rigid, glassy state at temperatures below its Tg
to a fluid or rubbery state at temperatures above the Tg. The Tg of
a polymer is typically measured by differential scanning
calorimetry (DSC) using the mid-point in the heat flow versus
temperature transition as the Tg value. A typical heating rate for
the DSC measurement is 20.degree. C./minute. The Tg of various
homopolymers may be found, for example, in The Polymer Handbook,
edited by J. Brandrup and E. H. Immergut, Interscience Publishers.
The Tg of a polymer is calculated by using the Fox equation (T. G.
Fox, Bull. Am. Physics Soc., Vol. 1, issue no. 3, page 123,
1956).
[0018] "(meth)acrylate" refers to either acrylate or
methacrylate.
[0019] "Molecular weight" may be defined in several different ways.
Synthetic polymers are almost always a mixture of many different
molecular weights, i.e., there is a "molecular weight
distribution", or "MWD". For a homopolymer, members of the
distribution differ in the number of monomer units which they
contain. This idea also extends to copolymers. Given that there is
a distribution of molecular weights, the most complete
characterization of the molecular weight of a given sample is the
determination of the entire molecular weight distribution. This
characterization is obtained by separating the members of the
distribution and then quantitating the amount of each that is
present. Once this distribution is at hand, there are several
summary statistics, or moments, which can be generated from it to
characterize the molecular weight of the polymer.
[0020] The two most common moments of the distribution are the
"weight average molecular weight", "Mw", and the "number average
molecular weight", "Mn". These are defined as follows:
Mw=.SIGMA.(WiMi)/.SIGMA.Wi=.SIGMA.(NiMi2)/.SIGMA.NiMi
Mn=.SIGMA.Wi/.SIGMA.(Wi/Mi)=.SIGMA.(NiMi)/.SIGMA.Ni
[0021] where:
[0022] Mi=molar mass of the ith component of distribution
[0023] Wi=weight of the ith component of distribution
[0024] Ni=number of chains of the ith component
[0025] and the summations are over all the components in the
distribution. Mw and Mn are typically computed from the MWD as
measured by Gel Permeation Chromatography ("GPC").
[0026] "Hydrophobic monomer", as used herein, means a monomer
having a Hansch .pi. value of at least 3.5.
[0027] The hydrophobic monomers suitable for use in the present
invention are monomers having a Hansch .pi. value of at least 3.5.
Examples of such hydrophobic monomers include 2-ethylhexyl
acrylate, butyl methacrylate, stearyl methacrylate, cetyliscosyl
methacrylate and lauryl methacrylate.
[0028] The vinyl aromatic monomers which may be utilized are
preferably selected from styrene and various substituted styrenes.
Exemplary substituent groups include 2-bromo, o-bromo, p-chloro,
o-methoxy, p-methoxy and methyl. Many conventional traffic paints
omit styrene monomers from their formulations because of styrene's
known tendency to degrade when exposed to the UV radiation to which
traffic paints are typically subjected. However, the inventors of
the present subject matter have found that these monomers may be
successfully employed to enhance the adhesive properties of the
present invention on oily road surfaces.
[0029] In addition to the hydrophobic monomer(s) described above,
the remainder of the monomer mixture may include at least one or
more of the following hydrophilic monomers having a Hansch .pi.
value of less than 3.5. Some of these hydrophilic monomers
include:
[0030] Methyl acrylate, ethyl acrylate, methyl methacrylate,
hydroxyethyl (meth)acrylate and hydroxy propyl (meth) acrylate;
(meth)acrylamide or substituted (meth) acrylamides, substituted
with alpha-alkyl or aryl groups or N-alkyl or aryl groups; vinyl
monomers, such as, for example, vinyl pyridine, N-vinyl
pyrrolidone, acrylonitrile or methacrylonitrile. Additionally
copolymerizable ethylenically-unsaturated acid monomers in the
range of from 0.1% to 10%, by weight, based on the total weight of
the polymer solids, of a acrylic acid, maleic acid, monomethyl
itaconate, monomethyl fumarate, monobutyl fumarate, maleic
anhydride, 2-acrylamido-2-methyl-1-propanesulfonic acid, sodium
vinyl sulfonate, phosphoethyl methacrylate, and combinations
thereof may be used.
[0031] The polymers used in the inventive composition have a Tg in
the range of from -25.degree. C. to 25.degree. C., preferably in
the range of -1020 C. to 10.degree. C. Most preferred are polymers
having a Tg of from -5.degree. C. to 5.degree. C.
[0032] The polymers used in the present invention have a low
molecular weight. As used herein, the term "low" identifies
polymers having a weight average molecular weight ("Mw"), as
measured by conventional GPC techniques, in the range of from 1000
to 200,000, most preferably in the range of 1000 to 100,000. The
polymer of the inventive composition may be a dispersed polymer
having polymer particles dispersed in an aqueous evaporable carrier
or it may be either a water soluble polymer, a water reducible
polymer, a mixture of the water soluble and water reducible
polymers in the aqueous evaporable carrier, or a mixture of the
dispersed, water reducible and water soluble polymers in the
aqueous evaporable carrier.
[0033] In the practice of the present invention, it is necessary to
maintain a correlation between the hydrophobic monomer content and
the Tg of the polymer, in order to achieve the highest degree of
adhesion possible to an oily roadbed. It has been discovered that
if the Tg of the polymer is on the lower end of the range of from
-25.degree. C. to 25.degree. C., then less of the hydrophobic
monomer(s) needs to be used. Polymers having glass dispersion
values in this range require as little as 10% hydrophobic monomer
content, up to a maximum of 99.9%. However, as the glass transition
temperature of the polymer increases, such as in the range of from
520 C. to 25.degree. C., the hydrophobic monomer content must also
increase. For polymers in this Tg range, especially on the high
side of this range, at least 20% hydrophobic monomer content is
required, up to a maximum of 99.9%.
[0034] The polymerization techniques which may be used for
preparing the polymers of the present invention are well known in
the art. The polymers may be prepared by aqueous solution
polymerization or by emulsion polymerization. Emulsion
polymerization is preferred. Either the thermal or redox initiation
processes may be used. Polymers of alpha-beta ethylenically
unsaturated monomers and their esters, especially the acrylic and
methacrylic esters, are preferably prepared by processes described
in "Emulsion Polymerization of Acrylic Monomers: May 1966", a
publication of the Rohm and Haas Co., Phila. Pa.
[0035] The polymerization process is typically initiated by
conventional free radical initiators, such as, for example,
hydrogen peroxide, benzoyl peroxide, t-butyl hydroperoxide, t-butyl
peroctoate, ammonium and alkali persulfates, typically at a level
of 0.05 to 3.0 percent by weight, based on the total weight of the
monomer. Redox systems using the same initiators coupled with a
suitable reductant such as, for example, sodium bisulfite may be
used at similar levels.
[0036] It is necessary to limit the length of the polymer chain in
order to achieve the objectives of this invention. Various methods
are known in the art of polymerization for obtaining this result.
Three of the most well known methods involve the control of the
reaction temperature, the catalyst level or the amount and type of
chain transfer agents. The use of chain transfer agents is
preferred, although any other method capable of providing polymers
of low molecular weight may be utilized. Suitable chain transfer
agents include halo-organic compounds, such as carbon tetrabromide
and dibromodichloromethane; sulfur containing compounds such as
alkylthiols including ethanethiol, butanethiol, tert-butyl and
ethyl mercaptoacetate, as well as aromatic thiols; or various other
organic compounds having hydrogen atoms which are readily
abstracted by free radicals during polymerization. Additional chain
transfer agents include, but are not limited to, butyl
mercaptopropionate, isooctyl mercaptopropionic acid, bromoform,
carbon tetrachloride and alkyl mercaptans, such as, 1-dodecanthiol,
t-dodecyl mercaptan and n-dodecyl mercaptan ("nDDM"). Mercaptans
are preferred with nDDM being the most preferred.
[0037] A water reducible or water soluble polymer may be prepared
directly in water if the monomer mix is water soluble.
Alternatively, a water miscible solvent may be used, in which case
water may be included in the polymerization mixture or is added
after the polymerization process is complete. Water soluble or
water reducible polymers produced this way may be blended together
with dispersed polymers if so desired.
[0038] The drying time of the newly applied traffic paint may be
accelerated in many ways. The paint may contain a polyfunctional
amine together with an anionically stabilitzed latex and a volatile
base. Examples of polyfunctional polyamines include p(OXEMA),
p(vinylamine) and polyethyleneimine. Additionally, latexes
containing pendant amine functionality, derived from a number of
methods, including copolymerizing amine functional monomer into the
latex polymer or subsequently reacting a latex polymer to yield
amine groups attached to the latex polymer may be used to
accelerate the drying of a traffic paint. When a polyfunctional
amine is used it may be present in the paint or it may be added as
a separate component before, during or after the paint is applied.
U.S. Pat. No. 5,804,627 provides additional information on the use
of polyfunctional polyamines in traffic paint. U.S. Pat. No.
5,922,398 provides additional information on the use of latex
polymers containing pendant amine functionality.
[0039] Absorbers may be used to accelerate the drying of traffic
markings. The absorbers should be able to absorb and/or adsorb
small molecules like water, ammonia, C1-C6 alkylamines, C1-C6
alcohols, and mixtures thereof. Examples of absorbers include, but
are not limited to, ion exchange resins, hollow sphere polymers,
molecular sieves, organic super absorbing polymers, inorganic
absorbents, porous and non-porous carbonaceous materials and
mixtures thereof. U.S. Pat. No. 5,947,632 provides additional
information on the use of absorbers in traffic paint.
[0040] Drying of traffic paint may also be accelerated by
contacting the paint with an acid during application of the paint.
The acid may be in the form of an acid solution, an acid containing
powder or glass beads coated with an acid. The acid may be applied
to the paint or sprayed into a spray mist of the paint during the
application of the paint. U.S. Pat. No. 5,544,972 should be
consulted for further details on this method. Any of the previously
identified methods used to accelerate the drying of traffic paint
may be combined as required by the application.
[0041] If desired and depending on the intended use of the traffic
paint, additional components may be added to the composition. These
additional components include, but are not limited to, thickeners;
rheology modifiers; dyes; sequestering agents; biocides;
dispersants; pigments, such as, for example, calcium carbonate,
talc, clays, silicas and silicates; fillers, such as, for example,
glass or polymeric microspheres, quartz and sand; anti-freeze
agents; plasticizers; adhesion promoters; coalescing agents;
wetting agents; waxes; surfactants; slip additives; defoamers;
preservatives; corrosion inhibitors and anti-flocculants.
[0042] According to the method of the present invention, a layer of
aqueous traffic paint is applied to the surface of an oily roadbed.
The traffic paint may be applied using application techniques known
in the art, such as, for example, by spraying onto the road surface
by means such as truck mounted spray guns where the traffic paint
is forced through a spray nozzle(s) from an air pressurized tank or
by means of an airless pump. If desired, the traffic paint may be
hand applied by means of a paint brush or paint roller. The wet
thickness of the layer of aqueous traffic paint generally varies
from 100 .mu.m to 3000 .mu.m, and is preferably from 350 .mu.m to
1000 .mu.m.
[0043] If desired, the method of the present invention may include
dropping glass beads on the newly applied traffic paint before it
is completely dry. The glass beads which adhere to the top of the
traffic paint act as light reflectors. If glass beads are not used,
the traffic markings would be difficult to see under night and wet
weather conditions. As a result, nearly all traffic markings today
contain some amount of glass beads, usually in the range of 0.72 to
2.9 kilograms per liter of paint. The application of glass beads
may be by any conventional method, such as by dropping them at a
selected rate out of a hopper which is positioned in close
proximity to the traffic paint applicator. The glass beads are
dropped onto the freshly applied traffic paint while the paint is
still wet tacky. This allows the glass beads to adhere to the top
surface of the traffic paint as it dries.
[0044] The following examples, including comparative examples, are
provided to show the advantages of the claimed invention.
EXAMPLES
Example 1
[0045] To 900 g of deionized (DI) water under a nitrogen atmosphere
at 90.degree. C. was added 6.3 g of ammonium bicarbonate dissolved
in 50 g DI water, 7.8 g ammonium persulfate dissolved in 92 g DI
water and 131 g polymer seed latex (solids content 42% average
particle diameter of 60 nm) followed by 20 g of DI water to form a
reaction mixture to which the following monomer mixture was then
added over 3 hours at 85.degree. C. along with a solution of 5.2 g
ammonium persulfate dissolved in 50 g DI.
1 Monomer mixture: in grams (g) DI water 625 Surfactant * 33.5
butyl acrylate 1200.0 styrene 766.0 acrylic acid 34.0
n-dodecylmercaptan 20.0 * Ethoxylated C6-C18 alkyl ether sulfate
having 1 to 40 EO groups per molecule (30% active in water)
[0046] At the end of the polymerization, 0.01 g FeSO.sub.4 in 9 g
DI water, 0.01 g Versene.RTM. 220 in 9 g of DI water, 4.0 g
t-butylhydroperoxide in 30 g DI water and 2.0 g isoascorbic acid in
30 g DI water were added at 60.degree. C. to the reaction product.
Ammonium hydroxide was added to give a final pH=10. The resulting
latex polymer had a solids content of 50.8% and an average particle
diameter of 225 nm.
Example 2
[0047] To 750 g of deionized (DI) water under a nitrogen atmosphere
at 90.degree. C. was added 6.4 g sodium carbonate dissolved in 70 g
DI water, 6.4 g ammonium persulfate dissolved in 70 g DI water and
150 g polymer seed latex (solids content 42% average particle
diameter of 60 nm) followed by 40 g of DI water to form a reaction
mixture to which the following monomer mixture was then added over
3 hours at 85.degree. C. along with a solution of 4.2 g ammonium
persulfate dissolved in 70 g DI.
2 Monomer mixture: in grams (g) DI water 750 Surfactant * 31.5
Versene .RTM. 220 (1.5% active) 6.8 butyl acrylate 460
methylmethacrylate 814 methacrylic acid 26 2-ethylhexylacrylate 700
n-dodecylmercaptan 20.0 * Ethoxylated C6-C18 alkyl ether sulfate
having 1 to 40 EO groups per molecule (30% active in water)
[0048] At the end of the polymerization, 0.01 g FeSO.sub.4 in 9 g
DI water, 0.01 g Versene.RTM. 220 in 1 g DI water, 1.8 g
t-butylhydroperoxide in 20 g DI water and 0.6 g isoascorbic acid in
20 g DI water were added at 60.degree. C. to the reaction product.
Ammonium hydroxide was added to give a final pH=9.8. To this was
added 94 g of p(OXEMA)* (26.6% active). The resulting latex polymer
had a solids content of 49.2% and an average particle diameter of
177 nm.
[0049] * p(OXEMA) is poly(oxazolidinoehtylmethacrylate). It may be
prepared according to the procedure shown in EP 0950763A1.
Example 3
[0050] To 800 g of deionized (DI) water under a nitrogen atmosphere
at 88.degree. C. was added 6.4 g of sodium carbonate dissolved in
50 g DI water, 6.4 g ammonium persulfate dissolved in 50 g DI water
and 64 g monomer mixture 3 followed by 20 g of DI water to form a
reaction mixture to which the remaining monomer mixture was then
added at 85.degree. C. along with a solution of 4.2 g ammonium
persulfate dissolved in 75 g DI.
3 Monomer mixture 3: in grams (g) DI water 800 Surfactant * 31.5
2-ethylhexyl acrylate 1066 Methylmethacrylate 908 methacrylic acid
26 n-dodecylmercaptan 20.0 * Ethoxylated C6-C18 alkyl ether sulfate
having 1 to 40 EO groups per molecule (30% active in water)
[0051] At the end of the polymerization, 0.01 g FeSO.sub.4 in 9 g
DI water, 1.8 g t-butylhydroperoxide in 20 g DI water and 0.6 g
isoascorbic acid in 20 g DI water were added at 60.degree. C. to
the reaction product. Ammonium hydroxide was added to give a final
pH=10.1. To this was added 93 g of p(OXEMA) (26.6% active). The
resulting latex polymer had a solids content of 49.7% and an
average particle diameter of 207 nm.
Example 4
[0052] To 800 g of deionized (DI) water under a nitrogen atmosphere
at 88.degree. C. was added 6.4 g of sodium carbonate dissolved in
50 g DI water, 6.4 g ammonium persulfate dissolved in 50 g DI water
and 64 g monomer mixture 4 followed by 20 g of DI water to form a
reaction mixture to which the remaining monomer mixture was then
added at 85.degree. C. along with a solution of 4.2 g ammonium
persulfate dissolved in 75 g DI.
4 Monomer mixture 4: in grams (g) DI water 800 Surfactant * 31.5
2-ethylhexyl acrylate 694 Methylmethacrylate 680 Styrene 200
methacrylic acid 26 n-dodecylmercaptan 20.0 * Ethoxylated C6-C18
alkyl ether sulfate having 1 to 40 EO groups per molecule (30%
active in water)
[0053] At the end of the polymerization, 0.01 g FeSO.sub.4 in 9 g
DI water, 1.8 g t-butylhydroperoxide in 20 g DI water and 0.6 g
isoascorbic acid in 20 g DI water were added at 60.degree. C. to
the reaction product. Ammonium hydroxide was added to give a final
pH=10.1. To this was added 93 g of p(OXEMA) (26.6% active). The
resulting latex polymer had a solids content of 49.6% and an
average particle diameter of 190 nm.
Example 5
[0054] To 800 g of deionized (DI) water under a nitrogen atmosphere
at 88.degree. C. was added 6.4 g of sodium carbonate dissolved in
50 g DI water, 6.4 g ammonium persulfate dissolved in 50 g DI water
and 64 g monomer mixture 5 followed by 20 g of DI water to form a
reaction mixture to which the remaining monomer mixture was then
added at 85.degree. C. along with a solution of 4.2 g ammonium
persulfate dissolved in 75 g DI.
5 Monomer mixture 5: in grams (g) DI water 800 Surfactant * 31.5
2-ethylhexyl acrylate 1000 Methylmethacrylate 774 Styrene 200
methacrylic acid 26 n-dodecylmercaptan 20.0 * Ethoxylated C6-C18
alkyl ether sulfate having 1 to 40 EO groups per molecule (30%
active in water)
[0055] At the end of the polymerization, 0.01 g FeSO.sub.4 in 9 g
DI water, 1.8 g t-butylhydroperoxide in 20 g DI water and 0.6 g
isoascorbic acid in 20 g DI water were added at 60.degree. C. to
the reaction product. Ammonium hydroxide was added to give a final
pH=10.1. To this was added 93 g of p(OXEMA) (26.6% active). The
resulting latex polymer had a solids content of 49.7% and an
average particle diameter of 194 nm.
Example 6
[0056] To 750 g of deionized (DI) water under a nitrogen atmosphere
at 90.degree. C. was added 6.2 g ammonium persulfate dissolved in
70 g DI water and 160 g polymer seed latex (solids content 42%
average particle diameter of 60 nm) followed by 20 g of DI water to
form a reaction mixture to which the following monomer mixture was
then added over 3 hours at 85.degree. C. along with a solution of
4.2 g ammonium persulfate dissolved in 70 g DI.
6 Monomer mixture 6: in grams (g) DI water 750 Sodium lauryl
sulfate (28%) 31.5 butyl acrylate 1080 styrene 886 acrylic acid 34
n-dodecylmercaptan 20.0
[0057] At the end of the polymerization, 0.01 g FeSO.sub.4 in 9 g
DI water, 0.01 g Versene.RTM. 220 in 1 g DI water, 1.8 g
t-butylhydroperoxide in 20 g DI water and 0.6 g isoascorbic acid in
20 g DI water were added at 60.degree. C. to the reaction product.
Ammonium hydroxide was added to give a final pH=9.8. To this was
added 94 g of p(OXEMA) (26.6% active). The resulting latex polymer
had a solids content of 49.8% and an average particle diameter of
235 nm.
Example 7
[0058] To 750 g of deionized (DI) water under a nitrogen atmosphere
at 90.degree. C. was added 10.8 g ammonium bicarbonate dissolved in
70 g DI water, 6.2 g ammonium persulfate dissolved in 70 g DI water
and 160 g polymer seed latex (solids content 42% average particle
diameter of 60 nm) followed by 20 g of DI water to form a reaction
mixture to which the following monomer mixture was then added over
3 hours at 85.degree. C. along with a solution of 4.2 g ammonium
persulfate dissolved in 50 g DI.
7 Monomer mixture 7: in grams (g) DI water 750 Sodium lauryl
sulfate (28%) 31.5 2-ethylhexyl acrylate 950 Methylmethacrylate
1024 methacrylic acid 26 n-dodecylmercaptan 20.0
[0059] At the end of the polymerization, 0.01 g FeSO.sub.4 in 9 g
DI water, 1.8 g t-butylhydroperoxide in 20 g DI water and 0.6 g
isoascorbic acid in 20 g DI water were added at 60.degree. C. to
the reaction product. Ammonium hydroxide was added to give a final
pH=9.8. To this was added 94 g of p(OXEMA) (26.6% active). The
resulting latex polymer had a solids content of 49.0% and an
average particle diameter of 189 nm.
Example 8
[0060] To 800 g of deionized (DI) water under a nitrogen atmosphere
at 88.degree. C. was added 6.4 g of sodium carbonate dissolved in
50 g DI water, 6.4 g ammonium persulfate dissolved in 50 g DI water
and 64 g monomer mixture 8 followed by 20 g of DI water to form a
reaction mixture to which the remaining monomer mixture was then
added at 85.degree. C. along with a solution of 4.2 g ammonium
persulfate dissolved in 75 g DI.
8 Monomer mixture 8: in grams (g) DI water 800 Surfactant * 31.5
2-ethylhexyl acrylate 1000 Methylmethacrylate 674 Styrene 300
methacrylic acid 26 n-dodecylmercaptan 20.0 * Ethoxylated C6-C18
alkyl ether sulfate having 1 to 40 EO groups per molecule (30%
active in water)
[0061] At the end of the polymerization, 0.01 g FeSO.sub.4 in 9 g
DI water, 1.8 g t-butylhydroperoxide in 20 g DI water and 0.6 g
isoascorbic acid in 20 g DI water were added at 60.degree. C. to
the reaction product. Ammonium hydroxide was added to give a final
pH=10.1. To this was added 93 g of p(OXEMA) (26.6% active). The
resulting latex polymer had a solids content of 49.7% and an
average particle diameter of 183 nm.
Comparative Example C1
[0062] To 750 g of deionized (DI) water under a nitrogen atmosphere
at 90.degree. C. was added 10.8 g ammonium bicarbonate dissolved in
70 g DI water, 6.2 g ammonium persulfate dissolved in 70 g DI water
and 160 g polymer seed latex (solids content 42% average particle
diameter of 60 nm) followed by 20 g of DI water to form a reaction
mixture to which the following monomer mixture was then added over
3 hours at 85.degree. C. along with a solution of 4.2 g ammonium
persulfate dissolved in 70 g DI.
9 Monomer mixture: in grams (g) DI water 750 Sodium lauryl sulfate
(28%) 31.5 Butyl acrylate 1200 Methylmethacrylate 774 methacrylic
acid 26 n-dodecylmercaptan 20.0
[0063] At the end of the polymerization, 0.01 g FeSO.sub.4 in 9 g
DI water, 1.8 g t-butylhydroperoxide in 20 g DI water and 0.6 g
isoascorbic acid in 20 g DI water were added at 60.degree. C. to
the reaction product. Ammonium hydroxide was added to give a final
pH=9.7. To this was added 94 g of p(OXEMA) (26.6% active). The
resulting latex polymer had a solids content of 49.8% and an
average particle diameter of 191 nm.
Comparative Example C2
[0064] To 750 g of deionized (DI) water under a nitrogen atmosphere
at 90.degree. C. was added 10.8 g ammonium bicarbonate dissolved in
70 g DI water, 6.2 g ammonium persulfate dissolved in 70 g DI water
and 160 g polymer seed latex (solids content 42% average particle
diameter of 60 nm) followed by 20 g of DI water to form a reaction
mixture to which the following monomer mixture was then added over
3 hours at 85.degree. C. along with a solution of 4.2 g ammonium
persulfate dissolved in 50 g DI.
10 Monomer mixture: in grams (g) DI water 750 Sodium lauryl sulfate
(28%) 31.5 butyl acrylate 1100 Methylmethacrylate 874 methacrylic
acid 26 n-dodecylmercaptan 20.0
[0065] At the end of the polymerization, 0.01 g FeSO.sub.4 in 9 g
DI water, 1.8 g t-butylhydroperoxide in 20 g DI water and 0.6 g
isoascorbic acid in 20 g DI water were added at 60.degree. C. to
the reaction product. Ammonium hydroxide was added to give a final
pH=9.8. To this was added 94 g of p(OXEMA) (26.6% active). The
resulting latex polymer had a solids content of 50.9% and an
average particle diameter of 191 nm.
Comparative Example C3
[0066] To 900 g of deionized (DI) water under a nitrogen atmosphere
at 90.degree. C. was added 6.3 g of ammonium bicarbonate dissolved
in 50 g DI water, 7.8 g ammonium persulfate dissolved in 92 g DI
water and 131 g polymer seed latex (solids content 42% average
particle diameter of 60 nm) followed by 20 g of DI water to form a
reaction mixture to which the following monomer mixture was then
added over 3 hours at 85.degree. C. along with a solution of 5.2 g
ammonium persulfate dissolved in 50 g DI.
11 Monomer mixture: in grams (g) DI water 625 Surfactant * 33.5
butyl acrylate 1200.0 styrene 766.0 acrylic acid 34.0 * Ethoxylated
C6-C18 alkyl ether sulfate having 1 to 40 EO groups per molecule
(30% active in water)
[0067] At the end of the polymerization, 0.01 g FeSO.sub.4 in 9 g
DI water, 0.01 g Versene.RTM. 220 in 9 g of DI water, 4.0 g
t-butylhydroperoxide in 30 g DI water and 2.0 g isoascorbic acid in
30 g DI water were added at 60.degree. C. to the reaction product.
Ammonium hydroxide was added to give a final pH=10. The resulting
latex polymer had a solids content of 50.8% and an average particle
diameter of 174 nm.
Comparative Example C4
[0068] Rhoplex Fastrack.RTM. 2706 commercially available from Rohm
and Haas Company, Philadelphia, Pa., U.S.A..
Comparative Example C5
[0069] Rhoplex Fastrack.RTM. 3427 commercially available from Rohm
and Haas Company, Philadelphia, Pa., U.S.A.
Comparative Example C6
[0070] To 900 g of deionized (DI) water under a nitrogen atmosphere
at 90.degree. C. was added 6.4 g of ammonium bicarbonate dissolved
in 34 g DI water, 5.3 g ammonium persulfate dissolved in 34 g DI
water and 132 g polymer seed latex (solids content 42% average
particle diameter of 60 nm) followed by 23 g of DI water to form a
reaction mixture to which the following monomer mixture was then
added over 3 hours at 85.degree. C. along with a solution of 7.9 g
ammonium persulfate dissolved in 71 g DI.
12 Monomer mixture: in grams (g) DI water 608 Surfactant * 33.8
butyl acrylate 1014.0 styrene 975.0 acrylic acid 34.5 * Ethoxylated
C6-C18 alkyl ether sulfate having 1 to 40 EO groups per molecule
(30% active in water)
[0071] At the end of the polymerization, 0.01 g FeSO.sub.4 in 9 g
DI water, 0.01 g Versene.RTM. 220 (available from Dow Chemical,
Midland Michigan) in 9 g of DI water, 4.0 g t-butylhydroperoxide in
30 g DI water and 2.0 g isoascorbic acid in 30 g DI water were
added at 60.degree. C. to the reaction product. Ammonium hydroxide
was added to give a final pH=9.7. To this was added 126 g of
p(OXEMA) (28.3% active). The resulting latex polymer had a solids
content of 51.1 % and an average particle diameter of 231 nm.
13TABLE I Polymer Characteristics According to the Invention
Example Percent Hydrophobic Monomer % nDDM* Tg 1 38.3 1.0 0 2 35
1.0 0 3 53.3 1.0 -2 4 44.7 1.0 -2 5 60 1.0 3 6 44.3 1.0 10 7 47.5
1.0 10 8 65 1.0 8 *nDDM: n-dodecyl mercaptan
[0072]
14TABLE II Polymer Characteristics Of The Comparative Examples
Example Percent Hydrophobic Monomer % nDDM Tg C1 0 1.0 0 C2 0 1.0
10 C3 38.3 0 0 C4 0 0 25 C5 0 * 25 C6 48.3 0 25 * Low molecular
weight within the range of the polymers of the invention
[0073] The above identified polymers were then added to paint
formulations in order to show the increased oily road adhesion
properties exhibited by the polymers of the present invention.
[0074] Preparation of Traffic Paints
[0075] Traffic Paints 1 through 8 and Comparative Traffic Paints C1
through C6 were prepared according to the following formulations.
The ingredients were added in the given order. The ingredients of
Part I (A through I) were added sequentially under high shear
agitation and then mixed for 15 minutes. Part II ingredients (J
through O) were then added sequentially, at an agitation speed
necessary to maintain a deep vortex. Once all ingredients were
added, the formulation was mixed for 15 minutes at a viscosity of
80 to 85 KU (Krebs Units).
15TABLE III Ingredients for Traffic Paints 1-8 and C1-C6 Pt A B C D
E F G H I J K L M N O 1 403.8 30.0 13.3 -- 7.0 2.8 5.4 100 758.6
22.6 6.2 7.4 0.6 -- 36.8 2 463.6 -- -- 7.3 -- 2.8 5.5 100 770.9
30.0 13.5 7.5 -- 5.1 -- 3 448.3 -- -- 7.3 -- 2.8 5.5 100 770.9 30.0
13.4 7.4 -- 8.0 10.5 4 449.2 -- -- 7.3 -- 2.8 5.5 100 770.9 30.0
13.4 7.4 -- 6.0 11.5 5 445.7 6.3 -- 7.3 -- 2.8 5.5 100 770.9 30.0
13.3 7.4 -- 7.0 7.0 6 433.3 9.0 -- -- 7.2 2.8 5.5 100 770.9 30.0
13.0 3.8 -- -- 19.6 7 460.6 -- -- 7.2 -- 2.8 5.5 100 770.9 30.0
13.5 3.8 -- 11.2 -- 8 443.9 -- -- 7.3 -- 2.8 5.5 100 770.9 30.0
13.2 7.4 -- 8.9 12.0 C1 465.8 -- -- 7.2 -- 2.8 5.5 100 770.9 30.0
13.7 -- 3.8 6.7 1.7 C2 448.3 -- -- 7.2 -- 2.8 5.5 100 770.9 30.0
13.7 -- 3.8 10.0 15.3 C3 422.0 -- 14.1 -- 7.4 2.8 5.5 100 757.4
30.0 13.0 -- -- -- 36.1 C4 460.1 -- -- 7.2 -- 2.8 2.0 100 760.6
30.0 23.0 3.5 -- 7.0 11.6 C5 455.5 -- -- 5.0 -- 2.8 3.0 100 760.3
30.0 23.0 2.5 -- 12.0 12.0 C6 424.1 38.0 -- -- 8.5 2.8 5.5 100
760.3 30.0 17.3 -- -- -- 23.3
[0076] Unless stated otherwise, the following ingredients were used
in the formulation of the paints identified hereinabove. All
weights are shown in grams.
16 A means the polymers made previously using the same numbers as
for the paints. B means water. C means p(OXEMA), defined
hereinabove. D means Tamol .RTM. 901 dispersant, supplied by the
Rohm and Haas Co., Phila. PA. E means Colloid .RTM. 226/35
dispersant, supplied by Rhodia, Inc., Cranbury, N.J. F means
Surfonyl .RTM. CT-136 surfactant, supplied by Air Products, Inc.
Allentown, PA. G means Drewplus .RTM. L-493 defoamer, supplied by
Drew Chemical Co., Boonton, N.J. H means TiPure .RTM. R-900
titanium dioxide supplied by E. I. duPont de Nemours & Co.,
Wilmington, DE. I means Omyacarb .RTM. 5, ground natural calcium
carbonate, supplied by Omya, Inc., Proctor, VT. J means methanol. K
means Texanol .RTM., an ester alcohol supplied by Eastman
Chemicals, Kingsport, TN. L means benzophenone (30% in methanol). M
means Acrysol .RTM. SCT-275, a rheology modifier supplied by Rohm
and Haas Co., Phila., PA. N means Natrasol .RTM. 250 HR supplied by
Aqualon, Inc., Wilmington, DE. O means water.
[0077] Adhesion Tests
[0078] The following tests were performed to show the improved
adhesive properties of the traffic paints formulated according to
the invention.
[0079] Oil Patch Adhesion: Using a standard commercial grade
automotive motor oil, a 6".times.12" oil patch is brushed onto the
surface of a test section of a concrete based road surface. After
waiting for approximately 1 hour, the traffic paint to be tested is
applied by spraying it as a line positioned transverse to the
direction of traffic flow. The test lane is then opened up for
traffic approximately 1 hour after paint application. At selected
time intervals (typically from 1 to 6 weeks), the paints are
evaluated for adhesion loss by being rated on a scale of from 0 to
10, with 10 representing no loss of adhesion, 0 representing total
loss of adhesion and the values in between used to indicate varying
degrees of adhesion loss.
[0080] Cross-Hatch Adhesion: 6".times.12".times.1 concrete blocks
are formed by curing Portland Type I cement in polypropylene molds.
The blocks are allowed to cure for a minimum of 1 month. Onto the
smooth facing of each test block is applied approximately 3 grams
of a standard commercial grade automotive motor oil, then rubbing
evenly to apply a uniform film. After 24 hours, the test paint to
be evaluated is applied onto the oily surface by using a 10 mil
drawdown bar, thus forming a 7 mil wet film. After the paint is
allowed to dry for 24 hours, a razor is used to scribe a grid
pattern of 100 squares, each of which approximately 2 mm by 2 mm in
size. The tacky surface of a conventional adhesive tape is securely
applied onto the 100 square grid pattern by rubbing the back
surface to the tape with an eraser for 10 seconds. The tape is then
removed from the paint film by rapidly pulling it at approximately
a 45.degree. angle. By counting the number of squares still
adhering to the oily concrete surface, the degree of adhesion of
the traffic paint being tested is determined and is recorded as "%
Adhered".
17TABLE IV Examples According to the Invention Oil Patch Adhesion*
Oily Concrete Cross-Hatch Adhesion Example 2 weeks 6 weeks %
Adhered 1 10 10 95 2 -- -- 80 3 10 10 90 4 10 10 80 5 10 10 85 6 --
-- 95 7 8 5 70 8 10 10 100 Note: *Testing was conducted on Rte.
202S in Southeastern Pennsylvania.
[0081]
18TABLE V Comparative Examples Oil Patch Adhesion* Oily Concrete
X-Hatch Adhesion Example 2 weeks 6 weeks % adhered C1 5 2 15 C2 4 0
20 C3 6 2 35 C4 0 0 0 C5 4 1 0 C6 5 1 10 Note: *Testing was
conducted on Rte 202S in Southeastern Pennsylvania.
[0082] The above examples show the improvements observed in the
adhesiveness of traffic paints using polymers created according to
the invention. As can be seen from Table IV, low molecular weight,
low Tg polymers having a significant hydrophobic monomer content
exhibited superior adhesion when the paints into which they were
formulated were applied to oily surfaces. In contrast, those
polymers not produced according to the method of the present
invention yielded poor adhesive characteristics. Comparative
examples C1 and C2 show that polymers produced without any
hydrophobic content failed to adhere at all to oily surfaces.
Comparative examples C3 and C6 consisted of large molecular weight
polymers which also failed to adhere to such surfaces. While
Comparative examples C4 and C5 both did not contain any hydrophobic
monomer content, modulating the molecular weight (high Mw in C4 vs.
low Mw in C5) failed to significantly affect performance.
[0083] It is evident that only when polymers are produced having
each of the three physical properties within the scope of the
present invention that traffic paint which includes these polymers
readily adheres to road bed surfaces no matter whether these
surfaces may be partially or completely covered with oily
substances.
* * * * *