FIELD OF INVENTION
[0001] The present invention is directed to a painting operation and method for controlling
the viscosity of a coating composition wherein the coating composition is a sprayable
mixture containing protected crosslinkable groups. This spray-applied mixture subsequently
forms a layer of the coating composition which can be dried and cured to form a durable
protective coating on a substrate.
BACKGROUND OF INVENTION
[0002] Automobile coatings typically comprise crosslinked polymer network formed by multiple
reactive components. The coatings are typically sprayed onto a substrate such as automobile
vehicle body or body parts using a spray device and then cured to form a coating layer
having such crosslinked polymer network.
[0003] In spray technologies currently used, multiple reactive components of a coating composition
are mixed to form a pot mix prior to spraying and placed in a cup-like reservoir or
container that is attached to a spraying device such as a spray gun. Due to the reactive
nature of the multiple reactive components, the pot mix will start to react as soon
as they are mixed together causing continued increase in viscosity of the pot mix.
Once the viscosity reaches a certain point, the pot mix becomes practically un-sprayable.
The possibility that the spray gun itself may become clogged with crosslinked polymer
materials is also disadvantageous. The time it takes for the viscosity to increase
to such point where spraying becomes ineffective, generally up to a two-fold increase
in viscosity, is referred to as "pot life".
[0004] Long pot life coating mixtures can be produced using crosslinkable groups that are
protected. The protected crosslinkable groups do not react to form the crosslinked
network until they have undergone a deprotection reaction. Protected crosslinkable
groups are able to form pot mixes containing the crosslinkable components, the crosslinking
components and the crosslinking catalysts having a long pot life. When these pot mixes
are spray applied to a substrate, humidity in the air can be enough to cause the hydrolysis
reaction to occur and form a crosslinked network. However, there is a relatively narrow
range of ambient humidity that will allow this coating composition to crosslink at
a useful rate. Too much humidity and the appearance can be unacceptable, and too low
of a humidity and the applied layer of coating composition can cure too slowly.
[0005] Another way to extend "pot life" is to add a greater amount of thinning solvent,
also known as thinning agent, to the pot mix. However, thinning agent, such as organic
solvent, contributes to increased emissions of volatile organic compounds (VOC) and
also increases the curing time.
[0006] Other attempts to extend "pot life" of a pot mix of a coating composition have focused
on "chemical-based" solutions. For example, it has been suggested to include modifications
of one or more of the reactive components or certain additives that would retard polymerization
reaction of the multiple components in the pot mix. The modifications or additives
must be such that the rate of curing is not adversely affected after the coating is
applied to the surface of a substrate.
[0007] Another approach is to mix one or more key components, such as a catalyst, together
with other components of the coating composition immediately prior to spraying. One
example is described in
U.S. Patent No. 7,201,289 in that a catalyst solution is stored in a separate dispenser and being dispensed
and mixed with a liquid coating formulation before the coating formulation is atomized.
[0008] Yet another approach is to separately atomize two components, such as a catalyst
and a resin, of a coating composition, and mix the two atomized components after spray.
One such example is described in
U.S. Patent No. 4,824,017. However, such approach requires atomization of two components separately by using
separate pumps and injection means for each of the two components.
STATEMENT OF THE INVENTION
[0009] The following disclosure relates to a painting operation and a method for controlling
the viscosity of a coating composition wherein said coating composition is a sprayable
mixture, said method comprising the steps of:
- (A) producing a first atomized stream of a first coating component of said coating
composition through an orifice of said spray gun with a stream of a pressurized carrier,
wherein said first coating component is stored in a first storage container and conveyed
through a first inlet of said spray gun to said orifice and wherein the viscosity
of said first coating component remains substantially constant prior to being conveyed
through said first inlet;
- (B) producing a second atomized stream of a second coating component of said coating
composition, wherein the second atomized stream is produced by siphoning the second
coating component with a siphoning stream selected from the stream of the pressurized
carrier, or a combination of the stream of the pressurized carrier and the first atomized
stream of the first coating component, from at least one delivery outlet coupled to
a second storage container containing said second coating component, said orifice
being relatively positionable with respect to said delivery outlet to siphon the second
coating component with different siphoning stream depending on the relative position
between the orifice and the delivery outlet;
- (C) optionally, regulating the supply of the second coating component to said delivery
outlet by coupling a regulatory device to said delivery outlet;
- (D) intermixing the first atomized stream and the second atomized stream to form a
coating mixture; and
- (E) applying the coating mixture on the substrate to form the layer of said coating
composition thereon; and
wherein the coating composition comprises protected crosslinkable functional groups,
and wherein said first coating component is mixture of a crosslinkable component and
a crosslinking component.
[0010] The method may further comprise the steps of:
- (i) producing a subsequent atomized stream of a subsequent coating component of said
coating composition, wherein the subsequent atomized stream is produced by siphoning
the subsequent coating component with the siphoning stream from at least one subsequent
delivery outlet coupled to a subsequent storage container containing said subsequent
component, said subsequent delivery outlet being positioned at said orifice;
- (ii) optionally, regulating the supply of the subsequent coating component to said
subsequent delivery outlet by coupling a subsequent regulatory device to said subsequent
delivery outlet;
wherein in step (D) the subsequent atomized stream is also intermixed to form the
coating mixture.
BRIEF DESCRIPTION OF DRAWING
[0011]
Figure 1 shows a spray gun affixed with an example of a representative delivery device of
this invention.
Figure 2 shows frontal views of the delivery device viewed from the direction 2A indicated
in Figure 1. (A) A schematic presentation of a representative example of the delivery
device 2D constructed as an add-on device. (B) A schematic presentation of a representative
example of the delivery device 2' having one delivery outlet constructed into the
air cap of the spray gun. (C) A schematic presentation of a representative example
of the delivery device 2" having two delivery outlets constructed into the air cap
of the spray gun. (D) A schematic presentation of a representative example of the
delivery device 2'" having three delivery outlets (14) constructed into the air cap
of the spray gun.
Figure 3 shows an enlarged frontal view, in a schematic presentation, of a representative
example of the delivery device 2D constructed as an add-on device that can be affixed
to an air cap of a spray gun. A single intake coupling (8) is shown.
Figure 4 shows an enlarged frontal view, in a schematic presentation, of another representative
example of the delivery device 2D' constructed as an add-on device that can be affixed
to an air cap of a spray gun. Two intake couplings (8) are shown.
Figure 5 shows an enlarged frontal view of details of the delivery device and the relative
position of the delivery device and the orifice of the spray gun. Two delivery outlets
(14), two connection paths (11) and one orifice (13) are shown. The arrows 6 indicate the direction of a cross-sectional view used in
Figures 6, 7 and 8.
Figure 6 shows an enlarged side cross sectional view of details of one example of the delivery
device and the relative position of the delivery device and the orifice of the spray
gun. The orifice (13) can be positioned in three different regions indicated with a, b and c, respectively.
Figure 7 shows schematic presentations of examples of the formation of a coating mixture.
(A) An example of a first coating component that is atomized at an orifice of a spray
gun without the introduction of a second coating component. (B) An example of the
coating mixture formed by an atomized first coating component and an atomized second
coating component.
Figure 8 shows schematic presentations of another example of the formation of a coating mixture.
(A) A first coating component atomized at an orifice of a spray gun without the introduction
of a second coating component. (B) A coating mixture formed by an atomized first coating
component and an atomized second coating component.
Figure 9 shows additional examples of the delivery device of this invention constructed as
an add-on device. (A) An example of the delivery device that has a configuration of
two intake couplings (8) and two delivery outlets (14). (B) An example of the delivery device that has a configuration of two intake couplings
(8) and one common delivery outlet (14). The orifice (13) is shown in the figure to indicate relative position of the delivery device when
affixed to the air cap. The orifice (13) is part of the spray gun.
Figure 10 shows schematic presentations of different configurations of the delivery device
of this invention. (A) An example of a delivery device having one intake coupling
that is coupled to one storage container. (B) An example of a delivery device having
one intake coupling that is coupled to two individual storage containers. (C) An example
of a delivery device having two intake couplings that are coupled to two storage containers.
(D) An example of a delivery device having three intake couplings that all three of
them are coupled to a single storage container. (E) An example of a delivery device
having three intake couplings that one of them is coupled to an individual storage
container while other two are coupled to a single container. (F) Another example of
a delivery device having three intake couplings that only one of them is coupled to
a single storage container. (G) Another example of a delivery device having three
intake couplings that two of them are coupled to a single storage container. (H) Another
example of a delivery device having three intake couplings that each of the first
and the second is coupled to an individual storage container while the third is not
coupled to any container. The schematic representations are for illustration purposes
only and items in the presentations may not be to scale. The orifice (13) is part of the spray gun.
Figure 11 shows an example of another representative configuration.
DETAILED DESCRIPTION
[0012] The features and advantages of the present invention will be more readily understood,
by those of ordinary skill in the art, from reading the following detailed description.
It is to be appreciated that certain features of the invention, which are, for clarity,
described above and below in the context of separate embodiments, may also be provided
in combination in a single embodiment. Conversely, various features of the invention
that are, for brevity, described in the context of a single embodiment, may also be
provided separately or in any sub-combination. In addition, references in the singular
may also include the plural (for example, "a" and "an" may refer to one, or one or
more) unless the context specifically states otherwise.
[0013] The use of numerical values in the various ranges specified in this application,
unless expressly indicated otherwise, are stated as approximations as though the minimum
and maximum values within the stated ranges were both proceeded by the word "about".
In this manner, slight variations above and below the stated ranges can be used to
achieve substantially the same results as values within the ranges. Also, the disclosure
of these ranges is intended as a continuous range including every value between the
minimum and maximum values.
[0014] As used herein:
The phrase "coating composition" means a solventborne or waterborne liquid composition
that can be applied to a substrate via a spray gun. The coating composition comprises
a crosslinkable component and a crosslinking component. Other additives that are used
to produce a coating composition are known in the art and, in general, are not discussed
herein. Such additives can include organic solvents, aqueous solvents, pigments, rheology
control agents, light stabilizers and leveling agents. The coating composition comprises
crosslinkable and crosslinking components mixed together to form a pot mix prior to
being spray applied using the method described herein. Also described is a coating
composition comprising crosslinkable and crosslinking components as separate components
that can be applied as separate components using the method described herein.
[0015] The phrase "pot mix" means a mixture comprising a crosslinkable component and a crosslinking
component that is formed prior to spray application. The pot mix can be added to the
first storage container (3).
[0016] "Low VOC coating composition" means a coating composition that includes less than
0.6 kilograms per liter (5 pounds per gallon), preferably less than 0.52 kilograms
per liter (4.3 pounds per gallon) and most preferably, less than 0.42 kilograms per
liter (3.5 pounds per gallon), of volatile organic component, such as certain organic
solvents. The phrase "volatile organic component" is herein referred to as VOC. VOC
level is determined under the procedure provided in ASTM D3960.
[0017] The phrase "viscosity of a component remains substantially constant" means that the
viscosity of the component shows, in one embodiment, an increase of less than 40%
over an 8 hour period. In another embodiment, the increase in viscosity is less then
25% over a 12 hour period, and in a third embodiment, the viscosity increase is less
than 10% over a 16 hour period. To measure the viscosity change over time, the viscosity
of a component is measured at the time when the component is initially prepared; the
component is stored in a covered container at room temperature for 8, 12 or 16 hours;
the viscosity of the component is measured again using the same technique. The difference
in the two viscosity measurements should not vary by more than percentages listed
above. Several methods to measure the viscosity of a liquid are available. In one
embodiment, the Zahn viscosity (in seconds) is measured.
[0018] "Productive paint" describes a coating composition wherein an applied layer of the
coating composition, 10 to 150 micrometers thick, can be dried and cured, in one embodiment,
in less than 20 minutes at 60°C or in less than 90 minutes at room temperature. In
another embodiment, the 10 to 150 micrometers thick layer of productive paint can
be dried and cured in less than 10 minutes at 60°C or in less than 45 minutes at room
temperature. In a third embodiment, the 10 to 150 micrometers thick layer of productive
paint can be dried and cured in less than 5 minutes at 60°C or in less than 20 minutes
at room temperature. Room temperature being defined as a temperature in the range
of from 21°C to 24°C.
[0019] By "dried and cured" is meant that the coating composition is crosslinked to the
point that handling the substrate will not mar the surface, the substrate is dry to
the touch and that dirt or dust won't stick to the surface. While some crosslinking
has occurred, additional crosslinking can continue over time which will allow for
the sanding and/or buffing of the applied layer, if necessary. Preferably, the sanding
and/or buffing operations can occur within one hour of being dried and cured, and
more preferably within one-half hour.
[0020] The phrase "consistent appearance" means that a measured appearance value of a layer
of a dried and cured coating composition applied at a time when the painting operation
begins, does not vary by a given percentage over the measured appearance value of
a layer of the same dried and cured productive paint applied at a time that is 8 hours
after the painting operation began. The measured appearance values can be one or more
of the distinctness of image (DOI), the long and short wavescan measurements of an
applied coating. For the DOI measurement, the percentage change should be less than
10 percent and for the long and short wavescan measurements, the change should be
less than 20 percent. As an example, a layer of a coating composition is applied to
a first substrate using the method described herein. The applied layer of coating
composition is dried and cured and the DOI, long and/or short wavescan measurements
of the coating is obtained. After at least 8 hours, a similarly prepared second substrate
is coated using the same method and with the same coating composition as was used
to coat the first substrate. This second substrate is dried and cured using the same
conditions as was used to dry and cure the first substrate. The measured appearance
values should not vary by more than the percentages listed.
[0021] Distinctness of image and the long and short wavescan measurements can be measured
using glossmeters or wavescan instruments available from Byk-Gardner USA, Columbia,
Maryland.
[0022] The phrase "good appearance" means that a dried and cured multi-layer of a coating
composition applied using the method described herein has a short wavescan measurement
of less than 40. Preferably, the short wavescan is less than 30. Most preferably,
the short wavescan is less than 20. The long wavescan can also be measured, and to
be considered as having a good appearance, the long wavescan measurement should be
less than 15. To determine the wavescan measurement, at least one of the applied primer,
basecoat or clearcoat layers should be applied according to the present method. In
one embodiment, at least the clearcoat composition is applied according to the disclosed
method, and in a second embodiment, at least the primer and clearcoat compositions
are applied according to the disclosed method. In a third embodiment a layer of primer,
basecoat and clearcoat compositions are applied using the disclosed method.
[0023] As used herein, "Crosslinkable component" includes a compound, oligomer or polymer
having protected crosslinkable functional groups positioned in each molecule of the
compound, oligomer, the backbone of the polymer, pendant from the backbone of the
polymer, terminally positioned on the backbone of the polymer, or a combination thereof.
The term "protected" means that the crosslinkable functional groups are not immediately
available for curing with the crosslinking groups, but first must undergo a reaction
to produce the crosslinkable functional groups. Suitable protected crosslinkable components
having protected crosslinkable groups include, for example, amide acetal, orthocarbonate,
orthoacetate, orthoformate, spiroorthoester, orthosilicate, oxazolidine or combinations
thereof.
[0024] The protected crosslinkable groups generally are not crosslinkable without an additional
chemical transformation. The chemical transformation for these groups can be a hydrolysis
reaction that unprotects the group to form a crosslinkable group that can then be
reacted with the crosslinking component to produce a crosslinked network. Each one
of these protected groups, upon the deprotection reaction, forms at least one crosslinkable
group. For example, upon hydrolysis, an amide acetal can form an amide diol or one
of two amino alcohols. As another example, the hydrolysis of an orthoacetate can form
a hydroxy group.
[0025] While the embodiments disclosed herein are intended to contain protected crosslinkable
groups, a portion of the crosslinkable component can contain compounds, oligomers
and/or polymers that have crosslinkable functional groups that do not need to undergo
a chemical reaction to produce the crosslinkable group. Such crosslinkable groups
are known in the art and include, for example, hydroxyl, acetoacetoxy, thiol, carboxyl,
primary amine, secondary amine, epoxy, anhydride, imino, ketimine, aldimine, silane,
aspartate or a suitable combination thereof.
[0026] "Crosslinking component" is a component that includes a compound, oligomer or polymer
having crosslinking functional groups positioned in each molecule of the compound,
oligomer, the backbone of the polymer, pendant from the backbone of the polymer, terminally
positioned on the backbone of the polymer, or a combination thereof, wherein these
functional groups are capable of reacting with the deprotected crosslinkable functional
groups on the crosslinkable component (during the curing step) to produce a coating
in the form of crosslinked structures. The crosslinking component can have on an average
2 to 25, preferably 2 to 15, more preferably 2 to 7, and even more preferably 3 to
5 crosslinking groups per molecule. Typical crosslinking components can be selected
from a compound, oligomer or polymer having crosslinking functional groups selected
from the group consisting of isocyanate, amine, ketimine, melamine, epoxy, carboxylic
acid, anhydride, and a combination thereof.
[0027] A coating composition can further comprise a catalyst, an initiator, an activator
or a combination thereof.
[0028] A catalyst can initiate or promote the reaction between reactants, such as between
the deprotected crosslinkable functional groups of a crosslinkable component and crosslinking
functional groups of a crosslinking component of a coating composition. The amount
of the catalyst depends upon the reactivity of functional groups. Generally, in the
range of from about 0.001 percent to about 5 percent, preferably in the range of from
0.01 percent to 2 percent, more preferably in the range of from 0.02 percent to 1
percent, all in weight percent based on the total weight of the crosslinkable component
solids, of the catalyst is utilized. A wide variety of catalysts can be used, such
as, for example, organotin compounds such as tin catalysts, dibutyl tin dilaurate,
tin (II) octanoate; 1,4-diazabicyclo[2.2.2]octane, zinc octoate, triphenyl phosphine,
quaternary ammonium compounds, strong bases, aluminum halides, alkyl aluminum halides
or tertiary amines, such as, triethylenediamine, depending upon the deprotected crosslinkable
and crosslinking functional groups. These catalysts can be used alone or in conjunction
with carboxylic acids, such as, acetic acid. One example of commercially available
catalysts is dibutyl tin dilaurate as FASCAT® series sold by Arkema, Bristol, Pennsylvania,
under respective trademark.
[0029] In one embodiment, an activator can be used to deprotect the protected crosslinkable
groups. Suitable activators include, for example, water, water and acid, organic acids
or a combination thereof. In one embodiment, water or a combination of water and acid
can be used as an activator to deprotect the crosslinkable component. For example,
water or water with acid can be an activator for a coating described in
PCT publication WO2005/092934, published on October 6, 2005, wherein water activates hydroxyl groups by hydrolyzing orthoformate groups that
block the hydroxyl groups from reacting with crosslinking functional groups.
[0030] In another embodiment, an activator can be a compound, oligomer or polymer containing
crosslinkable functional groups that react very quickly with the functional groups
of the crosslinking group or the activator can be polymers having a high concentration
of crosslinkable groups, for example, non-aqueous dispersion or hyperbranched polymers.
Such fast reacting compounds, oligomer or polymers can be added as one of the components
described herein to help to build the crosslinked network of the applied layer of
coating composition. Examples of crosslinkable functional groups that react quickly
with a crosslinking component comprising isocyanate groups include, amines and/or
aspartates.
[0031] An initiator can initiate one or more reactions. Examples can include photo initiators
and/or sensitizers that cause photopolymerization or curing of a radiation curable
coating composition, such as a UV curable coating composition upon radiation, such
as UV irradiation. Many photo initiators are known to those skilled in the art and
can be suitable for this invention. Examples of photo initiators can include, but
not limited to, benzophenone, benzoin, benzoin methyl ether, benzoin-n-butyl ether,
benzoin-iso-butyl ether, propiophenone, acetophenone, 1-hydroxycyclohexyl phenyl ketone,
2, 2-diethoxyacetophenone, ethylphenylpyloxylate, diphenyl (2,4,6-trimethylbenzoyl)-phosphine
oxide, phosphine oxide, phenyl bis (2,4,6- trimethyl benzoyl), phenanthraquinone,
and a combination thereof. Other commercial photo initiator products, or combinations
thereof, include, for example, DAROCURE® and IRGACURE® products available from Ciba
Specialty Chemicals Corporation, New York.
[0032] In conventional coating practice using protected crosslinkable functional groups,
the crosslinkable components and the crosslinking components can be mixed with the
crosslinking catalyst and/or activators immediately prior to spraying. These catalyzed
pot mixtures can have a pot life on the order of a few minutes to several hours, after
which the viscosity has increased to the point where the spray application of the
composition can become difficult. The pot life can depend on the ambient humidity,
the amount of water added to deprotect the protected crosslinkable groups and other
factors. Too much or too little water available either from the ambient humidity or
water added as an activator can impact not only pot life but the rate of curing and
the appearance of the dried and cured coating composition. The present disclosure
provides a method for controlling the viscosity of a coating composition so that the
pot life can be increased over conventional coating practice and that the appearance
of the dried and cured coating composition has a consistent appearance during the
entire application period. A layer of dried and cured coating composition applied
according to the disclosed method can also have a good appearance.
[0033] One embodiment of the disclosure is directed to a painting operation and a method
for controlling the viscosity of a coating composition wherein said coating composition
is a sprayable mixture comprising a protected crosslinkable functional group. The
coating composition can comprise two or more coating components. The method can comprise
the following steps:
- (A) producing a first atomized stream of a first coating component of said coating
composition through an orifice of said spray gun with a stream of a pressurized carrier,
wherein said first coating component is stored in a first storage container and conveyed
through a first inlet of said spray gun to said orifice, and wherein the viscosity
of said first coating composition remains substantially constant prior to being conveyed
through first inlet;
- (B) producing a second atomized stream of a second coating component of said coating
composition, wherein the second atomized stream is produced by siphoning the second
coating component with a siphoning stream selected from the stream of the pressurized
carrier, or a combination of the stream of the pressurized carrier and the first atomized
stream of the first coating component, from at least one delivery outlet of a delivery
device coupled to a second storage container containing said second component, said
orifice being relatively positionable with respect to said delivery outlet to siphon
the second coating component with different siphoning stream depending on the relative
position between the orifice and the delivery outlet;
- (C) optionally, regulating the supply of the second coating component to said delivery
outlet by coupling a regulatory device to said delivery outlet;
- (D) intermixing the first atomized stream and the second atomized stream to form a
coating mixture; and
- (E) applying the coating mixture on the substrate to form the layer of said coating
composition thereon,
wherein the coating composition comprises protected crosslinkable functional groups,
and wherein said first coating component is mixture of a crosslinkable component and
a crosslinking component.
[0034] The method can further comprise the steps of:
- (i) producing a subsequent atomized stream of a subsequent coating component of said
coating composition, wherein the subsequent atomized stream is produced by siphoning
the subsequent coating component with the siphoning stream from at least one subsequent
delivery outlet of the delivery device coupled to a subsequent storage container containing
said subsequent component, said subsequent delivery outlet being positioned at said
orifice;
- (ii) optionally, regulating the supply of the subsequent coating component to said
subsequent delivery outlet by coupling a subsequent regulatory device to said subsequent
delivery outlet;
wherein in step (D) the subsequent atomized stream is also intermixed to form the
coating mixture.
[0035] Any spray gun that can produce a stream of atomized coating composition can be suitable
for use with this method. A gravity feed spray gun is preferred. A gravity feed spray
gun using a pressurized carrier as an atomization carrier is further preferred. The
pressurized carrier can be selected from compressed air, compressed gas, compressed
gas mixture, or a combination thereof. Typically, the pressurized carrier can be compressed
air. Typically, a spray gun comprises a spray gun body (1), a nozzle assembly (2)
including an orifice (13) and an air cap (24), a carrier coupling (12) for coupling
to a source of a pressurized carrier, such as compressed air, an air regulator assembly
(25) for regulating flow rate and pressure of the carrier, a coating flow regulator
(21) for regulating the flow of the first coating component that is stored in a main
reservoir also known as a first storage container (3), and a first inlet (10) coupling
the spray gun (1) to the first storage container (3). The spray gun typically also
includes additional controls such as a trigger (22) and a spray fan regulator (20)
for regulating compressed air. In a typical gravity feed spray gun, the first coating
component is typically not pressurized and stored in the first storage container (3)
which is at atmosphere pressure. The first coating component can be conveyed to the
orifice by gravity, siphoning, or a combination of gravity and siphoning.
[0036] The pressurized carrier can be selected from compressed air, compressed gas, compressed
gas mixture, or a combination thereof. Typically, the pressurized carrier is compressed
air. Compressed gas, such as compressed nitrogen, compressed carbon dioxide, compressed
fluorocarbon, or a mixture thereof, can also be used. The compressed carrier can also
include gases produced from compressed liquids, solids, or reactions from liquids
or solids.
[0037] The coating composition can be a primer, a basecoat, a pigmented basecoat, or a clearcoat
composition. The coating layer formed therefrom can be a primer layer, a basecoat
layer, a pigmented basecoat layer, or a clearcoat layer, respectively.
[0038] In one embodiment of the present method, the first coating component can be a pot
mix comprising a mixture of the crosslinkable and crosslinking components of a coating
composition and the second coating component can include one or more materials selected
from a catalyst, an initiator, an activator or a combination thereof.
[0039] In some embodiments, mixtures of protected crosslinkable functional groups and crosslinkable
functional groups that are not protected can also be used. For example, the crosslinkable
component can be a mixture of compounds, oligomers or polymers containing both hydroxy
functional groups and amide acetal functional groups. In another example, the crosslinkable
component can be a blend of compounds, oligomers and polymers containing hydroxy functional
groups and compounds, oligomers and polymers containing orthoacetate functional groups.
[0040] Also described herein, the crosslinkable component can be the first coating component,
the crosslinking component can be the second coating component and a subsequent coating
component can be added that can be a catalyst, activator and/or initiator, or the
crosslinking component can be the first coating component, the crosslinkable component
can be the second coating component and, a subsequent coating component can be added
that can be a catalyst, activator and/or initiator.
[0041] In another embodiment, the first coating component can comprise a mixture of protected
crosslinkable functional groups and crosslinking components and the second coating
component can comprise water and/or acid to unprotect the protected crosslinkable
groups and subsequent coating components can be added which include one or more of
a catalyst, activator, and/or initiator.
[0042] Also described herein, the first coating component can comprise the protected crosslinkable
groups, the second coating component can comprise the crosslinking groups, and subsequent
coating components can include water and/or acid; catalysts; activators and/or initiators.
[0043] The crosslinking reactions used to form the crosslinked network can be addition reactions
from the polymerization of unsaturated double bonds using any of the disclosed initiators,
condensation reactions resulting from the condensation of, for example, a deprotected
crosslinkable functional group and an isocyanate group, or a combination of addition
and condensation reactions can form the crosslinked network.
[0044] Examples of the protected crosslinkable groups and the crosslinkable groups that
are produced after being unprotected are listed in Table 1. The crosslinkable groups
attained after unprotecting can determine the crosslinking groups that can be suitable
for use with each protected crosslinkable group.
TABLE 1
Protected Crosslinkable group |
Crosslinkable groups attained after unprotecting |
Amide acetal |
Amide diol and/or amino alcohols |
Orthocarbonate |
Hydroxyl |
Spiroorthocarbonate |
Hydroxyl |
Orthoacetate/orthoformate |
Hydroxyl |
orthosilicate |
Silanol |
oxazolidine |
Amine and alcohol |
[0045] The current method refers to a painting operation and helps to control the viscosity
of a coating composition wherein said coating composition is a sprayable mixture.
Controlling the viscosity of the coating composition prior to applying to the substrate
helps to maintain a consistent appearance of the subsequently cured coating composition
over the entire application period.
[0046] The disclosed method for controlling the viscosity of a coating composition can result
in a layer of a dried and cured coating composition having a consistent appearance.
The disclosed method can use a productive paint and provide a layer of a dried and
cured coating composition having a consistent appearance. The length of time that
it takes to apply the coating composition according to the present method is not particularly
critical, and can generally range from several minutes to 8 or more hours. While the
method can be used in any painting operation, it can be suitable to use in the automobile
refinish, the original equipment manufacturer (OEM) aviation, heavy duty truck and
marine industries, and many other industries that apply coating to substrates.
[0047] The method, as described herein, can be applicable in many commercial painting industries.
In the Fleet and auto auction markets, a quick curing coating is desired so as to
maximize production output. Generally, quick curing compositions are produced by increasing
the amount of catalyst added to the pot mix, which results in short pot life. With
the current method, the pot mix viscosity remains substantially constant during the
application, because the catalyst is not added until the atomization step. In the
aviation, heavy duty truck and marine coating industries, the substrates can be very
large. To coat such large areas, a long pot life composition is needed. Currently,
pot mixes with low levels of catalysts are able to provide the necessary pot life.
However, a low catalyst level results in a long cure time, which is undesirable. The
method as described herein can provide the desired long pot life and also a relatively
quick cure. In many other industrial coating operations, a very low VOC coating is
desired due to the expensive solvent/air separation techniques necessary to comply
with environmental regulations. These low VOC coatings typically have a short pot
life. The current method can provide for low VOC compositions and extended pot life.
In the primer/undercoat industry, large amounts of pigments and/or fillers are necessary
to give the coatings the desired properties and the pigments and/or fillers can affect
the catalyst activity over time due to the absorption of the catalyst onto the pigment/filler
surface. This can result in inconsistent curing and pot life issues. Adding the catalyst
at the atomization stage reduces the absorption of the catalyst onto the pigment/filler
surface which can help to eliminate the curing and pot life issues. It is also known
that catalysts and other ingredients that are typically added to clearcoat compositions
can lead to the discoloration of the uncured compositions prior to application. The
discoloration is often seen as a yellowing of the clearcoat compositions on storage.
The present method can be used to add the catalysts and other ingredients during the
spraying operation so that there is no color development prior to the application
of the composition.
[0048] In the above embodiments, the one or more components of the second coating component
can be siphoned separately such as in the configurations shown in Figures 9A, 10C,
10E or 10H. The one or more sub-components of the second coating component can be
siphoned together such as in the configurations shown in Figure 10B.
[0049] The second coating component can be siphoned from at least one delivery outlet (14)
with a siphoning stream selected from the stream of the pressurized carrier, or a
combination of the stream of the pressurized carrier and the first atomized stream
of the first coating component. The delivery outlet is coupled to a second storage
container containing said second component, said orifice being relatively positionable
with respect to said delivery outlet. Said delivery outlet and said orifice can be
positioned at any relative angles or relative positions such that the siphoning can
effectively take place. While not wishing to be bound by any particular theory, "siphoning"
is believed to occur when the siphoning stream is moving at high speed at the delivery
outlet causing negative air pressure around the delivery outlet. Such negative air
pressure is believed to cause the second coating component to be conveyed to the delivery
outlet. High velocity of the stream of the pressurized carrier and sudden change in
air pressure associated with the negative air pressure at the delivery outlet are
believed to cause the second coating component to become atomized and intermixed into
the siphoning stream and the first atomized stream of the first coating component.
In this invention, the first and the second coating components can be mixed at a pre-determined
mixing ratio to form the coating mixture. The second coating component can also be
conveyed to the delivery outlet by gravity or a combination of gravity and siphoning
in certain embodiments of configurations disclosed herein.
[0050] Both the first and the second coating component can be stored in respective storage
containers at atmosphere pressure.
[0051] Depending upon the relative position between the orifice (13) and the delivery outlet
(14), the second coating component can be siphoned with different siphoning stream.
When the orifice is positioned in the position illustrated by the region 13a and 13b
in
Figure 6, the second coating component can be siphoned primarily by the pressurized carrier
moving at high speed in the direction shown by the arrow (
32).
Figure 7 shows examples of a delivery device having two delivery outlets.
Figure 8 shows examples of a delivery device having one delivery outlet. The pressurized carrier
then continues to produce atomized first coating component at the orifice (13). The
atomized first and second coating component can be intermixed to form the coating
mixture (16) (Figures 7B and 8B). When the orifice is positioned in the position illustrated
by the region 13c in
Figure 6, the second coating component can be siphoned primarily by a combination of the pressurized
carrier moving at high speed in the direction shown by the arrow (32) and the first
atomized stream of the first coating component. If the second coating component is
not supplied to the delivery outlet, for example, if a regulatory device (32) is turned
off, then only the first coating component is atomized (15) (Figures 7A and 8A). Flow
of the first coating component is indicated by the arrow (
31). Flow of the second coating component is indicated by the arrows (
30).
[0052] The coating mixture can be applied over a substrate. Typically, a painter can hold
the spray gun at a certain distance from the substrate and move it in desired directions
so the coating mixture can be sprayed over the substrate forming a layer of the coating
composition. This invention can further comprise the step of curing the layer of the
coating composition on the substrate to form a coating thereon. This curing step can
depend upon the coating composition used. The layer can be cured at ambient temperatures,
or at elevated temperatures, such as up to 180°C. The curing can also be done by exposing
the coating layer to radiation, such as UV light or electron beam, when the coating
composition is radiation curable.
[0053] The substrate can include wood, plastic, leather, paper, woven and nonwoven fabrics,
metal, plaster, cementitious and asphaltic substrates, and substrates that have one
or more existing layers of coating thereon. The substrate can be a vehicle, vehicle
body, or vehicle body parts.
[0054] The method to control the viscosity of a coating composition can comprise the steps
of:
- (A) producing a first atomized stream of a first coating component of said coating
composition through an orifice of said spray gun with a stream of a pressurized carrier,
wherein said first coating component is stored in a first storage container and conveyed
through a first inlet of said spray gun to said orifice, and wherein the viscosity
of said first coating composition remains substantially constant prior to being conveyed
through said first inlet;
- (B) producing a second atomized stream of a second coating component of said coating
composition, wherein the second atomized stream is produced by siphoning the second
coating component with a siphoning stream selected from the stream of the pressurized
carrier, or a combination of the stream of the pressurized carrier and the first atomized
stream of the first coating component, from at least one first delivery outlet of
a delivery device coupled to a second storage container containing said second component,
said orifice being relatively positionable with respect to said delivery outlet to
siphon the second coating component with different siphoning stream depending on the
relative position between the orifice and the delivery outlet;
- (C) optionally, regulating the supply of the second coating component to said delivery
outlet by coupling a first regulatory device to said first delivery outlet;
- (D) producing a subsequent atomized stream of a subsequent component of said coating
composition, wherein the subsequent atomized stream is produced by siphoning the subsequent
coating component with the siphoning stream from at least one subsequent delivery
outlet of the delivery device coupled to a subsequent storage container containing
said subsequent component, said subsequent delivery outlet being positioned at said
orifice;
- (E) optionally, regulating the supply of the subsequent coating component to said
subsequent delivery outlet by coupling a subsequent regulatory device to said subsequent
delivery outlet;
- (F) intermixing the first atomized stream, the second atomized stream and the subsequent
atomized stream to form a coating mixture; and
- (G) applying the coating mixture on the substrate to form the layer of said coating
composition thereon,
wherein the coating composition comprises protected crosslinkable functional groups,
and wherein said first coating component is mixture of a crosslinkable component and
a crosslinking component.
[0055] The first delivery outlet and the subsequent delivery outlet can be separate delivery
outlets or combined into a single delivery outlet. Figures 2C, 2D, 4, 5, 6, 7, 9A
show some examples of separate delivery outlets. Figure 9B show one example where
two delivery outlets can be combined into a single delivery outlet. Based on disclosure
of this invention herein, more delivery outlets and/or different placement and positioning
of delivery outlets can be configured by those skilled in the art without departing
from the scope and spirit of this invention.
[0056] All the components, including the first and the second coating component, and any
subsequent component can be stored in respective storage containers at atmosphere
pressure.
[0057] One advantage of this invention is that said atomized first coating component, said
atomized second coating component, and any subsequent coating component if present,
can be mixed at a pre-determined mixing ratio to form said coating mixture without
the need for complex controls such as those described in aforementioned
U.S. Patent No. 4,824,017. The pre-determined mixing ratio can be determined by modulating or selecting the
size of the delivery outlet (14), the size of connecting path (11), or by providing
a regulatory device such as a flow rate controller functionally coupled to said delivery
device, or a combination thereof. It can be configured that one regulatory device
can regulate the flow rate of one or more delivery outlets. Mixing ratio can also
be controlled by modulating the viscosity of the first, the second or both the first
and the second coating components. In one example, viscosity of the second coating
component can be increased to reduce the amount being siphoned into the coating mixture.
In another example, viscosity of the second coating component can be reduced to increase
the amount being siphoned into the coating mixture. Similarly, viscosity of the first
coating component can be reduced or increased as needed to achieve a desired mixing
ratio.
[0058] The applicants unexpectedly discovered that using the method of this invention, mixing
ratio can be constant within a wide range of pressures of the pressurized carrier
ranging from 1,379 - 5,516 bar (20-80 pounds per square inch gauge (psig)). In one
example, pressure of the pressurized carrier can be in a range of from 1,724 to 4,826
bar (25 to 70 psig). In another example, pressure of the pressurized carrier can be
in a range of from 1,931 to 4,482 bar (28 to 65 psig). In yet another example, pressure
of the pressurized carrier can be in a range of from 2,068 to 4,137 bar (30 to 60
psig).
[0059] In one example, the mixing ratio can be determined by selecting different sizes of
the diameter of the delivery outlet. Coating mixtures formed by using different sizes
of the outlets can be sprayed onto suitable substrates. Properties of the coating
layers formed thereon can be measured. Based on the property measurement, a suitable
size or a range of suitable sizes of the delivery outlets can be selected. In another
example, the mixing ratio can be determined by selecting different size of diameter
of the connection path.
[0060] The regulatory device can be selected from a mechanical flow restrictor, an electric
flow restrictor, a pressure controlled flow restrictor, an actuated pneumatic flow
restrictor, or a combination thereof. Examples of a mechanical flow restrictor can
include a tube with a pre-determined flow pass diameter that is coupled to the delivery
outlet, or a mechanical valve that can control flow passage. Examples of an electronic
flow restrictor can include electrical valves or a electrical valve actuator. A pressure
controlled flow restrictor can be any mechanical or electric controllers that can
control flow based on pressure.
[0061] A flow rate controller, such as a valve or a commercial inline flow controller can
be coupled to the delivery outlet to adjust the flow of the second coating component
therefore affecting mixing ratio. A flow rate controller can also be a small insert
that is placed inside a connection path or a tubing connected to a connection path
that is coupled to the delivery outlet. Such an insert can effectively reduce the
size of the connection path or the tubing therefore reduces the flow of the second
coating component.
[0062] Selection of sizes and the use of flow rate controller can be combined. For example,
a size within a suitable range of the delivery outlet can be selected and a valve
can be coupled to the delivery outlet so the mixing ratio can be fine tuned. Any flow
rate controller that can be coupled to the delivery outlet can be suitable for this
invention.
[0063] A regulatory device can be coupled to a delivery outlet at any places that can effectively
regulate flow to that delivery outlet. The regulatory device can be coupled at an
intake coupling or be placed in a connection path connecting to that particular delivery
outlet. The regulatory device can also be placed at any place along a tubing that
delivers the second or the subsequent coating component from its storage container
to the intake coupling of the delivery device.
[0064] Another advantage of this invention is to have fast curing while maintaining extended
pot life. In conventional process, short pot life is a challenge when a coating composition
is formulated to be fast curing since all components are mixed together in a pot mix
and curing reaction starts immediately upon mixing. In this invention, the coating
composition can have extended pot life before spraying since one or more component
for cuing, such as a catalyst, is not mixed together. The coating composition can
then be cured rapidly after spraying since the second coating component, such as a
catalyst, is mixed after atomization during spraying.
[0065] Yet another advantage of this invention is that some aspects of spraying or the coating
property can be modified in an on-demand fashion. For example, curing time of a coating
composition can be modulated by modifying the amount of a catalyst mixed into the
coating composition during spraying. It can be done by tuning the regulatory device
while spraying.
[0066] Also described is a system for controlling the viscosity of a coating composition.
The system can comprise:
- (A) a spray gun comprising a spray gun body (1), one or more inlets, a nozzle assembly (2) including an orifice (13) and an air cap (24); and
- (B) a delivery device comprising:
- (i) at least one delivery outlet (14), wherein said delivery outlet being positioned at said orifice (13);
- (ii) at least one intake coupling (8); and
- (iii) at least one connection path (11) connecting said intake coupling (8) and said delivery outlet (14), wherein said delivery outlet is coupled through said connection path and said intake
coupling to a storage container (4) containing a second coating component;
- (C) optionally, a regulatory device (32) coupled to said delivery outlet regulating the supply of the second coating component
to said delivery outlet;
wherein a first atomized stream of a first coating component of said coating composition
is produced at said orifice (
13) with a stream of a pressurized carrier, wherein said first coating component is
stored in a first storage container and conveyed through a first inlet of said spray
gun to said orifice, and wherein the viscosity of the first coating component remains
substantially constant prior to being conveyed through said first inlet;
wherein a second atomized stream of a second coating component of said coating composition
is produced by siphoning the second coating component with a siphoning stream selected
from the first atomized stream of the first coating component, the stream of the pressurized
carrier, or a combination thereof, from said delivery outlet (
14) coupled to a second storage container containing said second component, and
wherein the coating composition comprises protected crosslinkable functional groups.
[0067] The delivery outlet (14), the intake coupling (8), and the connection path (11) can
be constructed as an add-on device affixed to the air cap of the spray gun, or can
be constructed into the air cap of said spray gun. Representative examples of the
add-on device can include the ones shown in Figures 2A, 3, 4, 9A and 9B. The add-on
device can be affixed to the air cap using conventional means such as one or more
screws, clips, clamps, adhesives, latches, or a combination thereof. Examples of the
delivery device constructed into the air cap can include those shown in Figures 2B,
2C and 2D. The delivery device can comprise one delivery outlet, such as those shown
in Figures 2A, 2B and 3. The delivery device can also comprise two or more delivery
outlets, such as those shown in Figures 2C, 2D, 4, and 9A. Two or more delivery outlets
can be combined into a single delivery outlet, such as the one shown in Figure 9B.
[0068] Representative configurations of the add-on device (2D) can be shown in Figures 2A,
3, 4, 9A, and 9B. The system can have a single delivery outlet (14), such as shown
in Figures 2A, 3, and 9B; or two or more delivery outlets (14) as shown in Figures
4 and 9A. Based on descriptions disclosed herein, those skilled in the art can make
modifications and re-configurations so the add-on device can be used with other spray
guns, nozzle assemblies, air caps, or a combination thereof.
[0069] Figure 5 shows an enlarged frontal view of the orifice (13) and two of the delivery outlets
(14).
Figure 6 shows a cross sectional side view of the delivery device indicating the relative
positions of two of the delivery outlets (14) and the orifice (13) wherein each of
the delivery outlets (14) is positioned at said orifice (13). As described before,
depending upon the relative position between the orifice (13) and the delivery outlet
(14), the second (or a subsequent) coating component can be siphoned with different
siphoning stream. Although perpendicular relative position is shown in the Figures
and examples of this disclosure, the delivery outlet and the orifice can be positioned
in any relative positions such that siphoning can effectively take place.
[0070] The system described herein can be configured to siphon a third or a subsequent component.
A delivery device of this invention can be configured to have multiple intake couplings
(8), multiple connection paths (11) or multiple delivery outlets (14) as shown in
representative examples in Figures 2C, 2D, 4, 9A, and 9B. Other examples of configurations
are shown in Figures 10A through 10H. In another representative configuration, two
or more connection paths can be combined at a point so the connection paths are connected
to a single delivery outlet (14), which can be positioned at the orifice (13). One
example is shown in Figure 9B.
[0071] The one or more intake couplings (8) can be configured to couple with one or more
individual storage containers (4) through direct coupling, such as plug on or screwed
on, or via connection means such as fixed or flexible tubing. Additional hardware
such as one or more "Y" shaped connectors can also be used. Examples of suitable configurations
are shown in Figure 10: (A) a delivery device having a single delivery outlet/intake
coupling that is coupled to a single container; (B) a delivery device having a single
intake coupling that is coupled to two individual containers; (C) a delivery device
having two outlets/intake couplings that are coupled to two individual containers
(shown) or a single container (not shown); (D) - (H) a delivery device having multiple
outlets and intake couplings that only some of them are coupled to one or more containers,
wherein the other intake(s) can be closed. When a delivery device has two or more
intake couplings and only one of them is coupled to a container, it is preferred to
close the un-coupled intake couplings via conventional means, such as a cap, a plug,
or a valve. Optionally, one or more regulatory devices (32) that controls flow rate,
such as a valve, an insert, a clamp, or a commercial inline flow controller can be
positioned and configured to control flow rate of one or more components at one or
more positions. The regulatory device can be selected from a mechanical flow restrictor,
an electric flow restrictor, a pressure controlled flow restrictor, or a combination
thereof. Those skilled in the art can design or modify configurations based on the
descriptions disclosed herein without departing from the spirit and scope of this
invention.
[0072] Figure 11 shows an example of another representative configuration. In this example, the container
(4) can be connected at the top of the intake coupling (8) via conventional connections,
such as a screw connection or a plug-in connection. A regulatory device (32), such
as a valve, can be placed in the path connecting the container (4) and the intake
coupling (8). In one example, the regulatory device (32) is a valve has two coupling
ends: one coupled to the intake coupling (8) and the other coupled to the container
(4). In another example, the regulatory device (32) is a valve built in the container
that can be coupled to the intake coupling (8). In yet another example, the regulatory
device (32) is a valve built in the intake coupling (8) that can be coupled to the
container (4). The regulatory device (32) can be turned on or off manually, or by
connecting to the trigger (22) mechanically or electronically. It is preferred that
the regulatory device (32) can be turned off when the spray gun is not spraying to
prevent leaking of the contents in the container (4) and can be turned on to allow
the content in the container (4) to flow to the delivery outlet (14).
[0073] The storage container (4) containing the second or a subsequent coating component
can be a flexible container, such as a plastic bag; a fixed-shape container, such
as a canister made of metal or hard plastic; or a flexible inner container inside
a fixed-shape container, such as a flexible plastic bag placed inside a fixed-shape
metal container. A flexible container that can be collapsed easily is preferred. The
flexible container can be a collapsible liner that can be sealed and used directly
or be placed inside a fixed shape container. The storage container can be transparent
or have a transparent window so the level of the content in the container can be readily
visible. The storage container can have an indicator to indicate the level of the
contents in the container. The storage container can be disposable or reusable. The
storage container can be coupled to an intake coupling (8) which is connected to the
delivery outlet (14) through a connection path (11). The storage container can be
coupled to the intake coupling (8) via conventional means, such as a clip, a clamp,
a set of matching screw tracks, or a plug-in. In one example, the storage container
comprises a tube that can be plugged into the intake coupling (8). In another example,
the storage container is screwed onto the intake coupling (8) via matching screw tracks.
In yet another example, the storage container is plugged into the intake coupling
(8) and secured by an additional fastener. The storage container can further have
a unidirectional flow limiter (26) to eliminate back flow, wherein said unidirectional
flow limiter can only allow the content to flow in one direction, such as only from
the container to the delivery outlet. Any back flow can be stopped by the directional
flow limiter to avoid potential contamination. For a fixed-shape container, ventilation
can be provided so the contents in the container can be maintained at atmosphere pressure.
1. In a painting operation, a method for controlling the viscosity of a coating composition
wherein said coating composition is a sprayable mixture, said method comprising the
steps of:
(A) producing a first atomized stream of a first coating component of said coating
composition through an orifice (13) of said spray gun with a stream of a pressurized
carrier (32), wherein said first coating component is stored in a first storage container
(3) and conveyed through a first inlet of said spray gun to said orifice (13) and
wherein the viscosity of said first coating component remains substantially constant
prior to being conveyed through said first inlet;
(B) producing a second atomized stream of a second coating component of said coating
composition, wherein the second atomized stream is produced by siphoning the second
coating component with a siphoning stream selected from the stream of the pressurized
carrier, or a combination of the stream of the pressurized carrier and the first atomized
stream of the first coating component, from at least one delivery outlet (14) coupled
to a second storage container (4) containing said second coating component, said orifice
(13) being relatively positionable with respect to said delivery outlet (14) to siphon
the second coating component with different siphoning stream depending on the relative
position between the orifice (13) and the delivery outlet (14);
(C) optionally, regulating the supply of the second coating component to said delivery
outlet by coupling a regulatory device to said delivery outlet;
(D) intermixing the first atomized stream and the second atomized stream to form a
coating mixture; and
(E) applying the coating mixture on the substrate to form the layer of said coating
composition thereon; and
wherein the coating composition comprises protected crosslinkable functional groups,
and wherein said first coating component is mixture of a crosslinkable component and
a crosslinking component.
2. The method of claim 1, wherein said protected crosslinkable functional groups are
selected from the group consisting of amide acetal, orthocarbonate, orthoester, spiroorthoester,
orthosilicate, oxazolidine and combinations thereof.
3. The method of claim 2, wherein the first coating component further comprises crosslinking
components selected from a compound, oligomer or polymer having crosslinking functional
groups and wherein the crosslinking functional groups are selected from the group
consisting of isocyanate, amine, ketimine, melamine, epoxy, carboxylic acid, anhydride,
and a combination thereof.
4. The method of claim 1, wherein the applied coating mixture can be dried and cured
in less than 20 minutes at 60°C or in less than 90 minutes at room temperature.
5. The method of claim 1, wherein said layer is a primer layer, a basecoat layer, a pigmented
basecoat layer, or a clearcoat layer.
6. The method of claim 1, wherein the second coating component comprises one or more
materials selected from a catalyst, an initiator, an activator or a combination thereof.
7. The method of claim 1, wherein said second coating component comprises water or water
with acid.
8. The method of claim 1, wherein said substrate is a vehicle, vehicle body, or vehicle
body parts.
9. The method of claim 1, wherein said regulatory device is selected from a mechanical
flow restrictor, an electric flow restrictor, a pressure controlled flow restrictor,
or a combination thereof.
10. The method of claim 1 further comprising the step of curing said layer of said coating
composition on the substrate to form a coating thereon.
11. The method of claim 1 further comprising the steps of:
(i) producing a subsequent atomized stream of a subsequent coating component of said
coating composition, wherein the subsequent atomized stream is produced by siphoning
the subsequent coating component with the siphoning stream from at least one subsequent
delivery outlet coupled to a subsequent storage container containing said subsequent
component, said subsequent delivery outlet being positioned at said orifice;
(ii) optionally, regulating the supply of the subsequent coating component to said
subsequent delivery outlet by coupling a subsequent regulatory device to said subsequent
delivery outlet; wherein in step (D) the subsequent atomized stream is also intermixed
to form the coating mixture.
12. The method of claim 11, wherein said protected crosslinkable functional groups are
selected from the group consisting of amide acetal, orthocarbonate, orthoester, spiroorthoester,
orthosilicate, oxazolidine and combinations thereof.
13. The method of claim 11, wherein said second or said subsequent coating component comprises
one or more materials selected from a catalyst, an initiator, an activator or a combination
thereof.
14. The method of claim 11, wherein said second or said subsequent coating component comprises
water or water with acid.
15. The method of claim 11 further comprising the step of curing said layer of said coating
composition on the substrate to form a coating thereon.
1. Bei einer Malerarbeit, Verfahren zum Einstellen der Viskosität einer Beschichtungszusammensetzung,
wobei die Beschichtungszusammensetzung eine sprühbare Mischung ist, wobei das Verfahren
die Schritte umfasst des:
(A) Herstellens eines ersten versprühten Stroms einer ersten Beschichtungskomponente
der Beschichtungszusammensetzung durch eine Öffnung (13) der Spritzpistole mit einem
Strom eines unter Druck gesetzten Trägers (32), wobei die erste Beschichtungskomponente
in einem ersten Speicherbehälter (3) gespeichert ist und durch einen ersten Einlass
der Spritzpistole zu der Öffnung (13) befördert wird und wobei die Viskosität der
ersten Beschichtungskomponente im Wesentlichen konstant bleibt, bevor sie durch den
ersten Einlass befördert wird;
(B) Herstellens eines zweiten versprühten Stroms einer zweiten Beschichtungskomponente
der Beschichtungszusammensetzung, wobei der zweite versprühte Strom durch Absaugen
der zweiten Beschichtungskomponente mit einem Absaugestrom ausgewählt unter dem Strom
des unter Druck gesetzten Trägers oder einer Kombination des Stromes des unter Druck
gesetzten Trägers und des ersten versprühten Stroms der ersten Beschichtungskomponente
aus einem Abgabeauslass (14), der an einen zweiten Speicherbehälter (4), der die zweite
Beschichtungskomponente enthält, angeschlossen ist, wobei die Öffnung (13) mit Bezug
auf den Abgabeauslass (14) positionierbar ist, um die zweite Beschichtungskomponente
mit einem anderen Absaugestrom, je nach der relativen Position zwischen der Öffnung
(13) und dem Abgabeauslass (14) abzusaugen;
(C) wahlweise Regulierens der Lieferung der zweiten Beschichtungskomponente zu dem
Abgabeauslass durch Verbinden der regulierenden Vorrichtung mit dem Abgabeauslass;
(D) Zusammenmischens des ersten versprühten Stroms und der zweiten versprühten Stroms,
um eine Beschichtungsmischung zu bilden; und
(E) Aufbringens der Beschichtungsmischung auf das Substrat, um eine Schicht der Beschichtungszusammensetzung
darauf zu bilden; und
wobei die Beschichtungszusammensetzung geschützte, vernetzbare, funktionelle Gruppen
umfasst und wobei die erste Beschichtungskomponente eine Mischung einer vernetzbaren
Komponente und einer vernetzenden Komponente ist.
2. Verfahren nach Anspruch 1, wobei die geschützten, vernetzbaren, funktionellen Gruppen
aus der Gruppe ausgewählt sind bestehend aus Amidacetal, Orthocarbonat, Orthoester,
Spiroorthoester, Orthosilicat, Oxazolidin und Kombinationen davon.
3. Verfahren nach Anspruch 2, wobei die erste Beschichtungskomponente ferner Vernetzungskomponenten
umfasst ausgewählt unter einer Verbindung, einem Oligomer oder Polymer, die/das vernetzende
funktionelle Gruppen aufweist und wobei die vernetzenden funktionellen Gruppen aus
der Gruppe ausgewählt sind bestehend aus Isocyanat, Amin, Ketimin, Melamin, Epoxy,
Carbonsäure, Anhydrid und einer Kombination davon.
4. Verfahren nach Anspruch 1, wobei die aufgebrachte Beschichtungsmischung in weniger
als 20 Minuten bei 60 °C oder in weniger als 90 Minuten bei Raumtemperatur getrocknet
und ausgehärtet werden kann.
5. Verfahren nach Anspruch 1, wobei die Schicht eine Grundiermittelschicht, eine Basislackschicht,
eine pigmentierte Basislackschicht oder eine Klarlackschicht ist.
6. Verfahren nach Anspruch 1, wobei die zweite Beschichtungskomponente ein oder mehrere
Materialien ausgewählt unter einem Katalysator, einem Initiator, einem Aktivator oder
einer Kombination davon umfasst
7. Verfahren nach Anspruch 1, wobei die zweite Beschichtungskomponente Wasser oder Wasser
mit Säure umfasst.
8. Verfahren nach Anspruch 1, wobei das Substrat ein Fahrzeug, eine Fahrzeugkarosserie
oder Fahrzeugkarosserieteil ist.
9. Verfahren nach Anspruch 1, wobei die regulierende Vorrichtung unter einem mechanischen
Strömungsbegrenzer, einem elektrischen Strömungsbegrenzer, einem druckregulierten
Strömungsbegrenzer oder einer Kombination davon ausgewählt wird.
10. Verfahren nach Anspruch 1, ferner den Schritt des Aushärtens der Schicht der Beschichtungszusammensetzung
auf dem Substrat umfasst, eine Beschichtung darauf zu bilden.
11. Verfahren nach Anspruch 1, ferner die Schritte umfassend des:
(i) Herstellens eines daraufhin versprühten Stroms einer darauffolgenden Beschichtungskomponente
der Beschichtungszusammensetzung, wobei der darauffolgend versprühte Strom durch Absaugen
der darauffolgenden Beschichtungskomponente mit dem Absaugstrom aus mindestens einem
darauffolgenden Abgabeauslass, der mit einem darauf folgenden Speicherbehälter verbunden
ist, der die darauffolgende Komponente enthält, hergestellt wird, wobei der darauffolgende
Abgabeauslass an der Öffnung positioniert ist;
(ii) wahlweise Regulierens der Lieferung der darauf folgenden Beschichtungskomponente
zu dem darauffolgenden Lieferauslass durch Verbinden der darauf folgenden regulierenden
Vorrichtung mit dem darauffolgenden Lieferauslass;
wobei in Schritt (D) der darauffolgende versprühte Strom ebenfalls vermischt wird,
um die Beschichtungsmischung zu bilden.
12. Verfahren nach Anspruch 11, wobei die geschützten, vernetzbaren, funktionellen Gruppen
aus der Gruppe ausgewählt sind bestehend aus Amidacetal, Orthocarbonat, Orthoester,
Spiroorthoester, Orthosilicat, Oxazolidin und Kombinationen davon.
13. Verfahren nach Anspruch 11, wobei die zweite oder darauffolgende Beschichtungskomponente
ein oder mehrere Materialien umfasst ausgewählt unter einem Katalysator, einem Initiator,
einem Aktivator oder einer Kombination davon.
14. Verfahren nach Anspruch 11, wobei die zweite oder darauffolgende Beschichtungskomponente
Wasser oder Wasser mit Säure umfasst.
15. Verfahren nach Anspruch 11, ferner den Schritt des Aushärtens der Schicht der Beschichtungszusammensetzung
auf dem Substrat umfassend, um eine Beschichtung darauf zu bilden.
1. Lors d'une opération de peinture, un procédé de commande de la viscosité d'une composition
de revêtement dans lequel ladite composition de revêtement est un mélange pouvant
être pulvérisé, ledit procédé comprend les étapes consistant à :
(A) produire un premier flux atomisé d'un premier composant de revêtement de ladite
composition de revêtement à travers un orifice (13) dudit pistolet de pulvérisation
avec un flux d'un support pressurisé (32), dans lequel ledit premier composant de
revêtement est stocké dans un premier récipient de stockage (3) et transporté grâce
à une première entrée dudit pistolet de pulvérisation audit orifice (13) et dans lequel
la viscosité dudit premier composant de revêtement reste sensiblement constante avant
d'être transporté à travers ladite entrée ;
(B) produire un deuxième flux atomisé d'un deuxième composant de revêtement de ladite
composition de revêtement, dans lequel le deuxième flux atomisé est produit en siphonnant
le deuxième composant de revêtement avec un flux de siphonnage choisi parmi le flux
du support pressurisé, ou une combinaison du flux du support pressurisé et du premier
flux atomisé du premier composant de revêtement, à partir d'au moins une sortie de
distribution (14) couplée à un deuxième récipient de stockage (4) contenant ledit
deuxième composant de revêtement, ledit orifice (13) pouvant être positionné de manière
relative par rapport à ladite sortie de distribution (14) afin de siphonner le deuxième
composant de revêtement avec un flux de siphonnage différent dépendant de la position
relative entre l'orifice (13) et la sortie de distribution (14) ;
(C) éventuellement, réguler l'apport du deuxième composant de revêtement à ladite
sortie de distribution en couplant un dispositif de réglementation à ladite sortie
de distribution ;
(D) intermélanger le premier flux atomisé et le deuxième flux atomisé afin de former
un mélange de revêtement ; et
(E) appliquer le mélange de revêtement sur le substrat afin de former la couche de
ladite composition de revêtement sur celui-ci ; et
dans lequel la composition de revêtement comprend des groupes fonctionnels réticulables
protégés, dans lequel ledit premier composant de revêtement est un mélange d'un composant
réticulable et d'un composant réticulable.
2. Procédé selon la revendication 1, dans lequel lesdits groupes fonctionnels réticulables
protégés sont choisis dans le groupe constitué de l'amide d'acétal, de l'orthocarbonate,
de l'orthoester, du spiroorthoester, de l'orthosilicate, de l'ozaxolidine et des combinaisons
de ceux-ci.
3. Procédé selon la revendication 2, dans lequel le premier composant de revêtement comprend
en outre des composants réticulables choisis parmi un composé, oligomère ou polymère
ayant des groupes fonctionnels réticulables et dans lequel les groupes fonctionnels
réticulables sont choisis dans le groupe constitué de l'isocyanate, de l'amine, de
la cétimine, de la mélamine, de l'époxy, de l'acide carboxylique, de l'anhydride et
d'une combinaison de ceux-ci.
4. Procédé selon la revendication 1, dans lequel le mélange de revêtement appliqué peut
être séché et durci en moins de 20 minutes à 60 °C ou en moins de 90 minutes à température
ambiante.
5. Procédé selon la revendication 1, dans lequel ladite couche est une couche de primaire,
une couche d'apprêt, une couche d'apprêt pigmentée ou une couche de revêtement transparent.
6. Procédé selon la revendication 1, dans lequel ledit deuxième composant de revêtement
comprend au moins un matériau choisi parmi un catalyseur, un initiateur, un activateur
ou une combinaison de ceux-ci.
7. Procédé selon la revendication 1, dans lequel ledit deuxième composant de revêtement
comprend de l'eau ou de l'eau avec un acide.
8. Procédé selon la revendication 1, dans lequel ledit substrat et un véhicule, un corps
de véhicule, ou des parties de corps de véhicule.
9. Procédé selon la revendication 1, dans lequel ledit dispositif de réglementation est
choisi parmi un limiteur d'écoulement mécanique, un limiteur d'écoulement électrique,
un limiteur d'écoulement à pression contrôlée ou une combinaison de ceux-ci.
10. Procédé selon la revendication 1, comprenant en outre l'étape de durcissement de ladite
couche de ladite composition de revêtement sur le substrat afin de former un revêtement
sur celui-ci.
11. Procédé selon la revendication 1, comprenant en outre les étapes consistant à :
(i) produire un flux atomisé supplémentaire d'un composant de revêtement supplémentaire
de ladite composition de revêtement, dans lequel le flux atomisé supplémentaire est
produit en siphonnant le composant de revêtement supplémentaire avec le flux de siphonnage
à partir d'au moins une sortie de distribution supplémentaire couplée à un récipient
de stockage supplémentaire contenant ledit composant supplémentaire, ladite sortie
de distribution supplémentaire étant positionnée au niveau dudit orifice ;
(ii) éventuellement, réguler l'apport du composant de revêtement supplémentaire à
ladite sortie de distribution supplémentaire en couplant un dispositif de réglementation
supplémentaire à ladite sortie de distribution supplémentaire ;
dans lequel dans l'étape (D) le flux atomisé supplémentaire est également intermélangé
afin de former le mélange de revêtement.
12. Procédé selon la revendication 11, dans lequel lesdits groupes fonctionnels réticulables
protégés sont choisis dans le groupe constitué de l'amide d'acétal, de l'orthocarbonate,
de l'orthoester, du spiroorthoester, de l'orthosilicate, de l'ozaxolidine et des combinaisons
de ceux-ci.
13. Procédé selon la revendication 11, dans lequel ledit deuxième composant de revêtement
ou ledit composant de revêtement supplémentaire comprend au moins un matériau choisi
parmi un catalyseur, un initiateur, un activateur ou une combinaison de ceux-ci.
14. Procédé selon la revendication 11, dans lequel ledit deuxième composant de revêtement
ou ledit composant de revêtement supplémentaire comprend de l'eau ou de l'eau avec
un acide.
15. Procédé selon la revendication 11, comprenant en outre l'étape de durcissement de
ladite couche de ladite composition de revêtement sur le substrat afin de former un
revêtement sur celui-ci.