Note: Descriptions are shown in the official language in which they were submitted.
D53~36
.:
Background of the 'Invention ',' ,'
Powder particles have become highly desirable as a means ,~
of coating'various substrates. For a description of powder
paints and methods of application see Iron Age, November 16, 1972,
pages 67 to 74, and Chemical'Engineering, July 12, 1971, pages ,, ,, ~;
36 to 38. Use of the particles has becomè of interest primarily ~ - ,
.: . .: , .
as powder paint. In other words, powder paint relates to the ,,,
application of-film-forming_materials_on,~o~,a substrate in order ' ,
to coat that substrate to give a desired finish wit~out the presence , '''~
of a solvent. The particles contain the film-forming substances ~' -
,':' :
and pigments. ~ ,
.: :
rJ.S. Patent ~,737,401 teaches'the method of preparing
" ' : ' ' ' ~ ~ ''
~6P 7210~-lM
36
~ .
powder paint by physically dividing a liquid paint, in the
presence of a coagulating liquid, to minute d~oplets o
uniform composition and subsequently diluting said droplets ~,
to remove the solvent.
It has been determined that the co~trol of the
shape of the particle that is produced by ~he process of
Patent 3,737,401 is desirable in order to control the film
characteristics of the coated materials as well as the
application of the powder to form the fil~. It is an object
of the present case to prepare powder particles of con-
trolled shape by modifying the conditions of preparation.Summary of the Invent~on
The invention is concerned with the preparation of
pow~er particles having a desired particle shape by em-
ploying the principle of mutual solubility. Droplets of
a paint solution will be formed con~aining the film-for~ing
portion and the solvent portion by contacting the liquid
~aint with a sol~ent that is mutually soluble with the
solvent for the paint and subsequently diluting the drop-
lets, removing the solvent for the film-forming portion
and controlling the shape of the powder particles. The
powder particles may remain dispersed in the final liquid
medium which would be the product of the process, or the
powder par~icles may be subsequen~ly separa~ed from the
1 - : .
solution, dried and packaged.
This invention is an impro~ement of the pr~cess
. .
for preparing powder particles descri~ed in U. S. Pa~ent
3,737,401. ~ -~
The particles produced according to this in~ention may have
one, two or three dimensions.
_ ~ _
;:
'
- A
.. , , .. .. , ~ ~ .
~ \ -` 1053086 B'&P 72104~
:,
Brief Description of *he Drawin~s ~
~
Fig.lis a schematic diagram of the process of :,
the present invention relating to the preparation of uni~ ~' '
dimensional powder particles; r
Fig. 2 is a schematic diagram of the process of
the present invention relating to the preparation of
powder particles having only two dimensions; ..
Fig. 3 is a schematic diagram of the process of ~;
the present invention relating to the preparation of
spherically shaped powder particles;
Fig. 4 is a schematic diagram of the process of -:'
:, .
the present invention relating to the preparation of ,~?~ ~,
irregularly shaped powder particles; and '~.. , . ' :
Fig. 5 is a schematic diagram of the process of the
present invention relating to the use of a sonic particle, ~';,,,:,' ~.
dispersing unit and various solvent separation and recovery `.'' , .:
steps. ' , '; .':.
Description of Preferred Embodiments
The invention of the present case is concerned with ''!,
the method of preparing powder particles having a desired
particle shape comprising the steps of: ` .'.
(1) providing a paint solution having ~ film-forming "s,,~,
portion and a first solvent portion, said first solvent
substantially dissolving the film-forming portion, `''
: -~ . .
(2) forming droplets containing the film-forming portion
and the first solvent portion by contacting said paint -.~.:.. ' '
solution with a second solvent which is partially miscible ~`.'':
wi~h the first solvent and in which the film-forming portion
is not soluble, the second solvent being substantially, ,.,"'
saturated with the first solvent, (3) diluting said droplets .'~'..~ '.-:
.'''','' ''~ ' '.
:. ' , ,. .:
-3~
, ,"i
53al~
B~P 72lo4-lM
, ~ ~
with a suf~icient qu~nti-ty of a third solvent which is
miscible with the first solvent and in which the film-
forming portion precipitates as powder paxticles, and (4)
controlling the shape of the powder particles by regulating
the xate of dilution of the first solvent in the droplets.
While applicant does not wi~h to be tied to any
particular theory as to the operability of the invention,
the particle shape is controlled following the below
described principles, it is believed.
i::
10When applicant refers to "one, two or three `
dimensions", it is meant that the particles formed
according to the process of the present invention may have
any one of the desired physical dimensions of substantially
,.: :
only length (one dimension), length and width (two dimen~
sions) or length, plus width plus depth (three dimensions).
Particles that can be considered substantially one
dimensional are fibrous or filamentary in nature much like '
a wire or thread, where the length is substantially
greater than the width, so that it can be said that there
20 is substantially no width. ;''
Particles that can be considered two dimensional
are much like plates or flat disks. The shapes may not '
be a fixed geometric shape, such as squara, triangular,
rectangular,'polygon, etc. but may be irregular with the ;-
only provision being that there is but two dimensions of
'length and width. '
The particles that can be considered three dimen- ~ -
sional have an appearance that can be considered spherical,
~ multifacetea~irregular, symmetrical, and the like.
Other parameters must also be taken into consider-
_ y_ :
.
S3~86
~&P 72104-lM
ation when applicant's mutual solvent system is employed
to fox~ particles of desired shape. When a solution of
film~forming compounds and solvent (hereinafter called
Solvent A) for the film-forming components is mixed with
another solvent (hereinafter called Solvent B), which is
a non-solvent for the film-orming components but whiah is
mutually solvent with Solvent A, fine droplets are formed
: i . . . - .
of Sol~ent A and film-forming components. If a suffiaient
period of time is permitted to pass, a spherical droplet ;
will be formed because this is the posture of the minimum
surface energy effected by sur~ace tension (interfacial
tension) between the droplet and Solvent B. This i5 the `
minimum energy level for the droplet.
It is believed that prior to applicant's invention,
there was no widespread commercially available way to obtain
powder paint particles of a substantially uniform composition,
other than irregular shaped particles which are obtained from
grinding dried paint drops or like processes. Some processes, -
such as the so called "Spray Dry" technique produced in ~ -
2~ limited amounts powder particles of a material composition
which is not heat sensitive, otherwise the drying at high
temperatures would deteriorate the desired compositions.
By engaging applicant's process one can obtain a substantially
uniform consistency of powder particles of the shape desired.
It should be pointed out that the powder compositions
produced according to ap~licant~s process have unique proper-
ties. If a substantially all spherical powder compositiOn is
employed, then the physical flowing properties of the com-
position will be improved since there is su~stantially less
friction involved as there would be for a substantially all
_ 5~
. :.....
3~6
, . ;
B&P 72104-lM
irregular shaped powder composition.
In addition it is believed that the rharacteristics
of film buildup and ability of particle to carry electrical
charge vary with the physical dimensions of the particle.
Therefore the film buildup is related to the ratio of
surface area of the particle to volume of the particle.
It is believed that a particle substantially spherical will ~-
take less charge during the electrostatic spraying of the
particle but that it also loses less charge during the
passage of the particle from the charging area (usually
spray gun) to the desired substra e. Conversely, an
irregular shaped paxticle will take more initial charge but
loses more charge, as compared to the spherical particles.
The all spherical powder composition when e~ectro-
statically sprayed may keep the charge entirely too long
for certain powders and will gather dust thereon due to ;
static electrcity. Also an all irregular shaped powder
composition when electrostatically sprayed will dissipate
its charge so rapidly that the powder particle may not have
sufficient charge to adhere to the desired substrate and
therefore cannot be electrostatically sprayed. This is pre- ~-
cisely the situation with respect to powdered polyvinyl
chloride currently available. The particle shapes are nat
sufficient to hold the charge for electrostatically spraying `~
the particle.
By employing applicant's process of preparing the
powder of varying desired shape~ film forming dielectric,
such as a PVC powder composition~can be electrostaticallY
sprayed resulting after cure in very ~ine film having a ~.
30 thickness of about 0.5 to about 5 mils, or lesg, to 3 mils. ~ :
:
~. .
.
~ID53~6
B&P 72104-IM
This can be accomplished by producing a powder composition
that is substantially spherical.
It can be seen that by following applicant's `
process, one now has the ability to vary another parameter ;~
(particle shape) in the application of a film former to a
substrate. If, for example, one has found that an all
spherical composition has certain undesirable results,
such as, holding static electricity, then one can vary the
shape from spherical, but yet, not totally irregularly
shaped. As can be seen, all of this can be done without
varying the film forming composition. It should be appre~ ;~
ciated however, that one may wish to design a film forming
composition which is to be used to produce a powder particle.
It is to be appreciated that applicant can produce
powder compositisns that are not necessarily limited to
powder paint ~Dmpositions but preferably are so limited.
Applicant can produce powder compositions which allow the
formation of the appropriate dimensional powder particle
to obtain the desired film property~ such as thickness,
20 hardness, color, hue, pigmentation, and the like. ~-
In view of the abo~e it can be seen that one may be
able to control the thickness of the paint film and therefore
overcome the dielectric or insulati~e nature of the film
because a higher charge can be held by spherical particles
than irregular shaped particles. Also one can var~ the flow !`. ~'
particles of the film by ~arying the particle shape.
Irregular shaped particles will flow at lower temperatures
than spherical shaped~ Therefore by merely altering the ;
particle shape one can alter the properties of the film
(fusion temperature, film thicknes~, and thP like).
, .. . .
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3D53~)~6 .
:
B~P 72104-lM
The first step of the process for preparing the
powder particles is providing a solution having a film-
forming portion and a first solvent portion. (Solvent A)
It is preferred that the solution be a paint prepared in the
normal processing techniques. In other words, the paint
would be a liquid paint containing a solution of the film-
forming portion which can be any one of a number of compositions
~uch as various resins as alkyd, urethanes, polyesters,
polyamides, epoxies, vinyls, such as from monomers as vinyl
chloride, acrylic acid or esters, methacrylic acid or esters,
acrylamide and N-substituted acrylamides, styrene, vinyl
toluene, copolymers thereof and the like, hydrocarbon resins,
varnishes, such as oleoresinous and spirit varnishes, and
the like. Of the above enumerated film-forming portions it
is preferred that an acrylic acid or ester or methacrylic
acid or estex resin be employed with the epoxy~ vinyl
chloride and polyester resins most preferred of the other
enumerated resins.
Other resins may also be used in applicant's process
to produce the desired powder composition. Any film form-
ing resin may be used, such as, polyolefins, such as, poly-
ethylene, polypropylene, and copolymers thereof, and the
like, polycyclopentadiene, polydienes, as, butadiene, is
oprene and copolymers thereof such as, styrene - butadiene
~SBR), acrylonitrile - styrene - butadiene (ABS3, and the
like, polyimides, organic~silicones, and the like.
The solution in which the film-forming portion is
dissolved is a solvent for the film-forming portion
(solvent A). In order to control the shape of the particle
the solution ha~ing the film-portion is contacted with a
3~6
B&P 72104-lM
second solvent (solvent B~ thereby forming droplets. The
droplets that are formed in this separate solution are of a
composition substantially similar to that o$ the first
solution. In other words, the droplets that are present
in solvent B have substantially the same ratio of the
film-forming portion to the solvent A portion as was
present in the solution of the first step. Solvent B
that is used is one that is partially miscible with the ~-
first solvent but is substantially non-soluble with respect
to the film-forming portion. The basis for this condition
is that solvent B is usually a stable medium for the first `~
~. .
solvent. Solvent B is a liquid medium in which the droplets -
will be formed of the film-forming portion but the relative
content of solvent A in these droplets is substantially
the same, for solvent B is substantially unable to dissolve ~ ;
substantial portions o~ solvent A so that the content of
solvent A in solvent B (or vice versal is not substantially
altered.
In some instances solvent B may be able to dissolve
some additional amount of solv~nt A. But this is generally
because the solvents ha~e not been agitated sufficiently
for equilibrium to be reached. All that is required for
solvent B is that it be a stable medium into which solvent A
plus film former may be added so that the droplets of film
former may be formed. When one employ~ solvents that are
partially miscible, two l~yers of solvent may form. When
the relati~e quantities of the two components (solvent A
and solvent ~) are such that the two liquid layers coexist,
one of the layers is a saturated solution of A in B while the
other is a saturated solution of B in A. The two liquid
.,. ~.
; ~ .. ' '
_ g _ ' '
53~
,...
- B&P 72104-lM
layers and phases in equilibrium are called conjugate
solutions. Outlined in Table I are representative
solvents are partially miscible in each. Therefore
while the ratio of solvent A to film former may vary
slightly when the droplets are formed in solvent B,
nonetheless, the droplets are formed due to the insolu-
bility of the film former in solvent B.
After the droplets are formed, the powder particles
may then be formed by removal of ~he solvent A from the
droplets. The various powder shapes are formed by the
dilution of the solvent A into a third solvent as well as
by mechanical or physical treatments of the droplets.
The principle being employed in the direct contact ~;
of the solvents is one that permits control of the removal
of solvent A from the film-forming portion.
Preparation of Unidimensional Powder Particles
Referring nvw to Figure 1, liquid paint 12, a
solution of solvent and film former, is contained in
tank 10 and is pumped or is flowed via line 14 into tank
16 having agitator 18. After a sufficient size of droplets
20 are ob~ained, due ~o the agitation, the solu~ion is then
passed via line 22 through a venturi 24 which is a lead to
a pipe through which solvent C is flowing. Due to the
swift movement of solvent C past the outlet of the venturi,
the solvent A is rapidly removed from ~he droplet and from
solvent B by being dil~ted into solvent C at the same tLme
the film former of the droplet is precipitated, thereby
being stretched into a fibrous of filamentary form 28
shown at the outlet of pipe 26
l~
16~53Q86 .:
B&P 72104-lM ;~ :
:. :: ..
.~ ,
PreDaration of Two Dime~sional Powder Particles
. ~:
The same procedure for unidimensional powder ,~ ::
preparation is followed with respect to the initial tanks that
are i'dentified as tank 10' and 16' with no substantial ~ `
difference in'the handling of the droplets formed in tank 16'
This is expresed in Figure 2. The droplets 33 from tank '~
16' are slowly dropped or sprayed onto a liquid surface 31
(solvent C~ in tank 30, having weir 32 and agitator 34 1 "
which allows for very slow movement of solvent C in tank 30
10 mexely sufficient to provide a surface of solvent C. :~:
Therefore once the disks or plates are formed at ~he surface
36 of solvent C then no further solvent A may be removed ~ :
therefrom and the powder particles remain in their shape
as was formed when they hit the surface o~ solvent C~
For practical purposes, solvent C should be one that has a high
surface tension, such as water, which can rapidly precipitate ;~
the powder by rapidly removing solvent A from the droplet. : '
Preparation of Three Dimensional Powder ~ .
Particles - Spherical Shaped
Following the same procedure for preparation of uni~
' ' '' ` "
dimensional powder particles with respect to employing the :,
first two tanks identified in Figure 3 as 10' and 16', after ':
agitation of the droplets to obtain satisfactory size and
spherical shape, the solution is then passed from tank 16' ~','
into tank 40 containing solvent C (42). The particles 44
that are formed are of ve~y fine ~ize r generally sphericalO
The solvent C is agitated by agitator 46 to allow for
complete removal of solvent A from the particles. To allow
uniform removal or dilution of solvent A into solvent C ~
:
the droplets are passed into 501 ution C under the surface
: . ,
, ~: . .
~ 3~
~ B~P 72104- lM
. ,
of solvent C at outlet 48 of pipe 22.
Formation of I~reg~lar Shaped Particles
-, Figure 4 schematically shows the formation of
irregularly shaped three dimensionally shaped particles.
Using the same liquid as in Figure 1 ~rom the first tank,
identified also as 10', a solution of solvent A and film
ormers is fed through line 50 directly into tan~ 52 con-
taining solvent C t54~ which immediately removes solvent A
from the droplets which are formed rather quickly. However `
before a spherical shape could be formed, the shaping is
interrupted and therefore irregularly shaped particles
56 result. The solution C in tank 52 is agitated by means
of agitator 58 in order to eliminate or remove as quickly
as possible, solvent A and dilute or dissolve it into
solvent C. The agitator also allows for physical means of
,' dividing the aroplets as the solvent A is being removed
therefrom. As can be seen from above, solvent C is a
~ilution solvent. The function of this third solvent is `;
, to remove in a controlled ~ashion solvent A thereby pre-
" 20 cipitating the powdered particles.
As can be appreciated, solvent C may vary from the
solvent B simply to the extent of the amount that the `~
, solvent A is present in the third solvent i.e. solvent B -~
and C may be comprised of the identical chemical compounds
or entities. In other words, since the solvent A is
partially soluble with the second and third solvent, one can
vary the content of the first solven~ in the third or
diluting solvent. Since the exten~ o~ dilution tor miscibility)
of one solvent in another is reasonably well known to one
of skill in the art, one may control the rate ~ha~ solvent A
.
-12-
S3~
~ , :
~ill leave the film-formln~ portion. Therefore, solvent C
may have substantially no solvent A in lt when it (the `
dilution solvent) first contacts or dllutes the droplets.
Suitable examples of solvents that may be employed see
j Table I. ~lso indicate~ is that amount that each is
soluble in the other. Therefore to control the rate of `
dilutlon of solvent A into solvent C, one therefore
varies the concentration of solvent A in solvent C.
Preferably sol~ent C has little or no solvent A therein. ~ ;
Most preferably solvent C is water. It should be appreciated
that one would select solvent A based on the amount necessary
Z to achieve conjugate solutions for in designing a complete
system~ one would separate such as by distillation, solvent A
from solvent C. The separation is designed to achieve
minimum energy requirements.
TABLE I - ;
i % by Weight S by Weight
I of Solvent A of ~2
Example~ of Sol~ent A in H20 in Solvent A
. , .::
Alcohols
1 - Butanol 7.7 20
` 20 2 - Butanol 20 36.3
Isobutanol 8.5 15
1 - Pentanol 2.6 9.5
2 - Pentanol 4.9 11 --
Amyl Alcohol
tmixed Isomers~ 1.7 9.2 ;
1 - Hexanol 0.58 7.2
2 - Ethyl Butanol 0.43 4.56
2 - Ethyl Hexanol 0.07 2.fi
2,6 - Dimethyl -4-
Heptanol 0.06 . 0~99
~sters .
MethyI Acetate 24.5 8.2
Ethyl Acetate '~ 8.7 3.3
` Butyl Acetate 0.68 1.2
Isopropyln~cetate 2.9 1.8
Cellosolv~rAcetate
~CH3COOC2H4OC2H5) 22c9 6.5
Butyl Carbitol Acetate
CB3C001C2H
Ethyleneglycol Diacetate 16 r 4 7 ~ O
1,3
; ~
. ~ ~ ` . ' , .
i` ,. .
, ~ , , , ,~- , , ,;,; i , . . . . .
.
~ 1~)53~6 ~
~-- , . : -.
TABLE I (Contlnued~
.:
: Ketones :- .
Met~y~r-~thyl Ketone 26,8 11.8 i .
Methyl propyl ketone 4.3 3.3 : : `
Methyl isobutyl ketone 1.9 1.6 .
;, Methyl-butyl ketone 1.42.1
Cyclohexanone 2.5 8.0
Glycol Ethers .
', C~H90 - CH2CH(CH3~ O~ 6.4 15.5
As is outlined above and in ~. S. 3,737,401, a
slurry of powder particles results from the process f ``
which may subsequently be filtered, washed, divided into
desired particle sizes and packaged as a slurry or dried
~;' 10 for dry powder packaging. An example of a slurry in which
the particles could be employed is described in U. S. ~ '
~'` Patent No. 3,787,230. .
~'. . It can be appreciated here that the particles
resulting from this process may be used for a desirable
number of end uses, such as dry particles for electro- `~
~i. static spraying, ~orming slurries for application to a
.. substrate such as metal and the like. It should also be - ~;
appreciated that the film-forming portion may include . .
. pigments which are normally used in liquid paints as well
: 20 as flow control agents to improve the flowing properties ::
. of the film formers during curing, catalysts to accelerate
-~` the curing of the:film and other agents to impart other
- desixable properties to the film. ~
In Figure 5 there is an a}ternate way of producing ~.
`-, the powders of controlled shape, Following the noxmal paint
.` manufacture, composed of solvent ~ and piyment and film
formers, a solution is prèpared in tank 60. As the liquid
is passed to diaphragm pump 62, soivent B is passed into :
, the line 64 upstream o~ the pump, thereby producing droplets
~` .30 66,~which are then passed to tank 68. :
y _
:~ ,
~53~36
- :. ` ``. :.
; Tank 68 is composed of an upper and lower portion ..
separated by a slotted V-shaped trough 74 through which : ~
the droplets pass. Solvent C 70 is present in the lower . . .......... .
portion. By means of a sonic dispersing means 76 the particles ~ `
78 are physicall.y divided as they are precipitated. The .
entire unit 68 is available from Sonic Engineering Corp. of
Norwalk, Conn. After passing from the sonic dispersing uni~
-I the finely divided particles are passed to a separation tan~
80 via line 79 which may be maintained at a sufficient le~el ;~
10 to allow the majox porti~n of particles to flow to subsequent .~ `;.
filtration via exit 8~. A good por~ion of the liquid may . .
then pass through filter 84 for subsequent separation and reuse.
The powder particles produced according to the
, .
process of the present invention generally range in size from
about 0.1 microns to about 150 microns, preferably for ;.~ .
electrostatic spraying having an average particle size of
-~ 35 microns or less. The fibrous particles may have a length
of up to 1,000 microns, although a length of 100 - 200 is : ;
. preferred and a cross-section of about 5 microns. .- ~: .
20 One ca~ also make oval shaped particles by the aboYe ..
:~ process for fibers wherein the length is about 1.5 times the
. diameter. ` `
~ ~ - ' : : . ;' ;
., .While having described the invention above in its .... ~
.`. .. general aspects, listed below are examples that further amplify .. :. ;
the invention wherein temperatures are given in degrees Fahrenhei~ . ...
~ .and percentages are percentages by weigh~ unless otherwise ~ : .;.
. ~ndicated. ;
~ .Example5 1-3
. A.green pigmented vinyl coating was prepared by
lO dissblving a.mixture of ~inyl powders: a) gO~ Ba~elite EZOOO : :
~inyl chloride resin of.medi~m molecular weight and melting
- lS ~
., -:.,
~:, - . .
. i i
l~S3~6
range o 120-135c) and b) Union Carbide VMCH (copolymer
of ~inyl chloride (86~) and vinyl acetate (13%) with 1% of
an interpol~nerized dibasic acid (0.7-0.8 carboxyl) in methyl
ethyl ketone (solvent A). Solvent B was methyl ethyl ketone
~ saturated in water while solvent C was deionized water. Table
;; II indicates the various amounts of components.
TABLE II (All Parts by Weight)
1 A B C
i Film former 20 35 40
Solvent A 80 65 60
Solvent B800-1200 800-1200 500-1500
Solvent c5600-17000 5500-16000 3200-200,000 -~
The particles were processed according to the steps
outlined in Fig. 3 so that they ~ere substantially spherical
having an average diameter of about 25 microns. The particles
~,
were separated from the water and dried. They were then electro-
statically sprayed at 45 KV onto a metallic panel. The treated ~-
panel was subjected to heat of 350F for 5 minutes whereupon a
smooth film of 1.5 mils was produced which can be characterized
as flexible, having a high tensile strength file with a tukon
hardness of 3-10.
The satio of solvent C to solvent ~ may be as low as
5-1 with no real upper limit. The practical upper limLt is
dictated by overall system design in optimi2ing the process ~~
~:` 1 .;
parameters, in particular, quality of powder, ability to
~` separate and reuse solvents~ and the like.
; It is to be appreciated that solvent C may~-be com- i
pletely miscible with solvent A. This may facilitate the di-
lution of solvent A from the dxoplets r Conversely, solvents
.,. :,
;30 B ~,C may be comp~ised o~ substantially identical chemical
entities. In the latter case~ solvents A ~ B should be only
partlally miscible.
B&P 72104-lM
~53~6
`:
Substantially equivalent results are obtained when `
a pigment, such as Tio2 is employed wi-th the film-former. ~'
Examples 4-12
Various solutions were prepared with the compo5ition
shown in Table III. The procedure for forming the particles
is as follows: Components No. 1 and 3 were added to No. 11
and then 2, 4, 8 and 10. Then Components 5 or 6 and 9 were
added. Just before precipitation, No. 7 is added. -
Solvent B (10% ethyl acetate, 90% water, by volume)
was prepared. The procedure shown in Figure 3 was followed. ~
After various solutions (4-12) were prepared, the pump in `
container 1~' was turned on and operated at 5,000 RPM. ~hen
each paint solution was pumped at about 100 pounds per inch2
gage through nozzels having an orifice diameter of 0. 012 I!
(nozzle with zero degree solid stream tip) into container 16' -
near the rotating agitator. Solvent B in container 16'
amounted to 10,000 ml. Fine droplets of spherical shape are
formed. After each solution was passed into container 16',
the total contents were then passed into a 55 gallon drum (40)
containing 30 gallons of deionized water which was agitated.
The contents of container 16' were pumped under the surface ;~
of the water in the drum and entered the drum near the agitator
and were allowed to wash for 1 to 2 hours. The particles pro-
duced had a composition substantially similar to the starting
liquid paint composition except the solvent was substantially
removed therefrom. The particles subsequently were separated
from the solution and dried. They were substantially spherical
and ranged in diameter from 5 to lS0 microns, which after
drying had a range of size of 10 to 75 microns.
~.. `I
: :
'!,', ' :
.,~., .
.,~, " .
~L053Q86 B&P 72104-lM
TABLE I I I
Component
Number 4 5 6 7 8 9 10 11 12
EPON-201 266 266266 ~ --0- 1~ 110 110 100
2 EPONOL 55--B-40 50 100 100 122 100244 270 270 300
3 OEX-1615 26.5 50 50 75 305 75 75 75 75
4 VMCA 78 31
Trimellitic
Anhydride -O- 35 -0-
6 A~alic Acid 51 47 25 25 25 25
7 SnO2 4 ~~ ~~ ~~
8 Moda10w 3 3 3 3 3 3 3 3 3
9 Cab-o-sil 1.5 1.51.5 1.5 1.5 1.51.5 -O- -0-
Ferro 840 5
11 Ethyl Acetate Adjusted to have 30% solids content
Epon -201 and Eponol 55-B-40 are trademarks of Shell Oil
Company for epichlorohydrin/bisphenol A type epoxy resin generally
of the structure
C ~2 ~ -CH2-~ ~ $ ~ 0-CH2CH-CH2]n-0 ~ -C ~ O CH C ACH
C~I3 CH3
OEX-1615 is a trademark of Union Carbide for a modified vinyl
, chloride resinous product. VMCA is a trademark of Union Carbide
for a vinyl resin having the composition parts by weight, of vinyl,
vinyl acetate and maleic acid (81/17/2). Modaflow is a trademark
Monsanto
of/and is a comple~ polymeric plasticizer and is soluble in
benzene, toluene, xylene, kerosene, petroleum ether, carbon ~ r
tetrachloride, mineral oil, approximately 2-3% by weight in iso-
propyl alcohol and increasingly soluble in higher alcohols,
`~ insoluble in water. Cab-o-sil is a trademark of Cabot Inc. and
~ is a thickening and thixotropic agent of a fumed silica type
., :
, which is produced by the hydrolysis of vaporized silicon tetra-
. " ~
chloride in a flame of hydrogen and oxygen. Ferr~ 840 i~ a trade- ~
mark of Ferro Chemical Corporation and is an alkyl tin heat ;
stabilizer having a specific gravity of 1.11 and a viscosity
, of A-l Garner.
;~` It is to be appreciated that the liquid paint solids may
also range up to 30 to 75% solids, if desired.
B~P 72104-lM
~53~ 6
Example 13
A solution (34% solids~ of the components of Table IV
was prepared and weighed 8.2 lbs. per gallon with a viscosity
of 64.2 seconds Ford Cup No. 4. The procedure for preparing
the droplets and particles was that of Examples 4-12, except
7.5 gallons of paint were used with 75 gallons of Solvent B
and the agitator in container 16' was operating at 1,000 RPM.
, .
TABLE IV
Parts By Weight
1 OEX-1615 53.94
2 VMCH 5.1 -
3 Cellulose Acetate Butyrate 4.0 `
4 Modaflow O4
5 Ferro 840 .8
6 EPON-201 2.0
7 Triisodecyl Trimellitate 7.84 ),~
, .
8 1,2,4-~Trioctyl Formate) Benzene 7.84
9 Ethyl Acetate 192.91 J,'~ , .
10 Carbon Pigment 1.65
See Table III for definition of the marks. -~
' After separation and drying, the particles obtained
were substantially spherical in shape and ranged in size
~' from a diameter of 10 microns to about 75 microns. The
composition of the particles is substantially the same as
~` the starting liquid paint composition except the sol~ent has
. :
been removed therefrom.
Example 14
~i Spherical shaped acrylic powder was prepared following
`,;i the procedure of E~amples 4-12. One part of liquid paint was
used with 10 parts of Solvent B (26.8% methyl ethyl kotone ~y
~l volume in water). The washing in the drum containing water
`~ lasted about 1 hour. The liquid paint had the composition of
, Table V. `~
i` 1 7 _ ` ~
, :
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1053~6 B~P 7210~
TABLE V
. Parts By Weight
Thermoplastic acrylic film-former
having hydroxyl functionality347.8
Cross-linking agent (isophorone
diisocyanate blocked with methyl
isobutyl ketoxime (equimolar) and
product reacted (equimolar) with
1,6-hexanediol) 34.0
~odaflow 2
Tio2 60
10 Methyl ethyl ketone 128
OH/NCO ratio (acrylic film-former/
cross-lin~ing agent)
: For a further description of the cross-linking agent
reference may be made to Canadian patent application Serial No.
.
229,729, filed June 19, 1975.
The particles produced according to this process were
substantially spherical in shape and ranged in diameter from
about S to 150 microns in the wet state and about 10 to about
75 microns in tbe dry state. `
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