 |
Description  |
|
|
BACKGROUND OF THE INVENTION
The majority of the processes used in the treatment of fibrous materials,
such as textiles and paper, entail immersion of the material in an aqueous
bath containing the treating compound. Consequently, the equipment used in
such processes includes facilities for the applying the aqueous
compositions followed by means for removing the excess water from the
treated substrate, such as squeeze rolls, extractors and driers. More
recently, processes for applying the treating compositions in the form of
a foam have been developed; however, the equipment or apparatus uses to
apply the foam leaves much to be desired, as can be seen from the
descriptions of U.S. Pat. No. 1,948,568, U.S. Pat. No. 3,697,314 and U.S.
Pat. No. 3,762,860. The equipment disclosed in these references requires
suspension of the textile in the foam bath, conveying the textile or yarn
through the foam, or padding the textile with the foam followed by heating
to break the foam.
SUMMARY OF THE INVENTION
This invention is directed to foam applicator heads that enable one to
uniformly and evenly apply in foam form a functional chemical textile
treating compound to the surface of a substrate. The applicator heads
comprise foam distribution chamber means, foam distribution plate means,
foam application chamber means, and nozzle means for the application of
the foam to the substrate in such manner that a predetermined and
controlled amount of the foamed functional treating compound is applied to
the substrate.
DESCRIPTION OF THE INVENTION
In the instant invention, a foam applicator head is described and claimed
that can be used with conventional foam generating means for the treatment
of a substrate, preferably a porous substrate, with a predetermined and
controlled amount of a foam. This equipment is more fully described below.
FIG. 1 is a schematic end view illustrative of a foam applicator head in
which both exterior longitudinal walls of the foam application chamber are
in fixed position.
FIG. 2 is a schematic end view illustrative of a foam applicator head in
which one exterior longitudinal wall of the foam application chamber is in
a fixed position and the position of the other exterior wall is
adjustable.
FIG. 3 is a schematic side view illustrative of a foam applicator head.
FIG. 4 and FIG. 5 are schematic views showing relative positions of the
nozzle lips and the angles thereof, as subsequently discussed in more
detail.
It is to be noted that figures and angles are not drawn to scale and are
presented to facilitate discussion and understanding of the claimed
invention. It is also to be noted that the figures do not show the means
for generating the foam and conducting it to the foam applicator head, the
means for conveying the substrate to and across the foam applicator head,
or the means for measuring temperature or pressure or other physical
constants. Note also that in the discussions the substrate is presumed to
be travelling in a right to left direction as indicated by the arrow.
The foam applicator heads of thie invention comprise, in combination, foam
distribution chamber means having foam inlet means connected thereto for
effecting transfer of foam from foam generating means into said foam
distribution chamber means, a foam distribution plate separating said foam
distribution chamber means from foam application chamber means, said foam
distribution plate having foam distribution holes therethrough to effect
movement of foam from said distribution chamber means to said foam
application chamber means, said foam application chamber means comprising
nozzle lips extending angularly from the plane of said foam distribution
plate to define a nozzle orifice, said nozzle orifice effecting
application of the foam to a substrate travelling across said nozzle
orifice, all of said chamber means enclosed at each end by end wall means.
Referring to FIG. 1 of the drawings there is shown an end view of an
embodiment of a foam applicator head in which both exterior longitudinal
walls of the foam application chamber are in fixed position and the nozzle
orifice width or nozzle slot opening can be adjusted in size by the use of
nozzle orifice adjusters. The drawing shows several configuration possible
for the nozzle orifice adjusters; these are identified as 1(a), 1(b),
1(c), 1(d), 1(e) and 1(f), with 1(a) and 1(b) shown bolted in position in
the foam application chamber 112. Though the drawing shows the use of
nozzle orifice adjusters 1(a) and 1(b), there may be instances in which
one may choose to use only a single nozzle orifice adjuster attached to
either the upstream nozzle lip 102 or the downstream nozzle lip 100, or
none whatsoever. This is dependent upon the construction of the foam
applicator head or the nozzle orifice width desired at any particular
time. Use of nozzle orifice adjusters enables broader utility of a single
foam applicator head.
The foam applicator head of FIG. 1 shows a foam inlet point 108 in the base
thereof. There can be more than one such foam inlet and while the drawing
shows its location in the base, it can be located at either end or in the
longitudinal side walls thereof feeding into the foam distribution chamber
106. The foam is fed into the foam distribution chamber 106 of the foam
applicator head via the foam inlet 108 at a positive pressure. In the foam
distribution chamber 106 a pressure equilibrium results as the foam
completely fills the foam distribution chamber 106 due to the flow
resistance imposed by the distribution plate 104 which separates the foam
distribution chamber 106 of the applicator head from the foam application
chamber 112. It is to be understood that there can be a multiplicity of
foam distribution chambers 106 and foam distribution plates 104 in series
with the foam flowing from a lower foam distribution chamber into at least
one intermediate foam distribution chamber and finally into the foam
application chamber, with foam distribution plates separating each
chamber. The number of foam distribution chambers may thus vary from 1 to
about 4 or more. However, it is preferred not to have more than 2 and the
number is determined by the effects upon the foam, i.e., they should not
be so numerous as to cause deterioration of the foam in the foam
distribution chambers as it flows from one chamber into another through
the foam distribution holes. This foam distribution plate 104 contains a
plurality of foam distribution holes 110 that permit the foam to travel
from the foam distribution chamber 106 into the foam application chamber
112. The number and sizes of the foam distribution holes 110 will vary
depending upon the size of the foam applicator head, the nature of the
foam, substrate being treated and the volume rate at which the foam
treatment is to be delivered to the substrate. When treating a substrate
wider than about 10 inches, uniformity of treatment across the width pf
the substrate is improved as the flow resistance imposed by the foam
distribution plate 104 is increased. The flow resistance should create a
differential pressure between the foam distribution chamber 106 and the
foam application chamber 112 of from about 3 to about 150 inches of water
pressure. The preferred pressure differential in any particular instance
varies and is dependent upon many factors, such as, the size of the foam
applicator head, the nozzle orifice width, the number of foam distribution
holes 110 in the foam distribution plate 104, the chemical and physical
make-up of the foam itself, the substrate being treated, the amount
desired to be added to the substrate, the velocity of the substrate over
the nozzle lips, etc. However, this can be adjustable by careful
preliminary evaluation. Too low a pressure differential will cause
non-uniform application of the foam across the width of the substrate. Too
high a pressure differential can cause rupture of the foam as it passes
through the foam distribution holes 110, or even plugging of said holes. A
convenient means for adjustment is the use of plugs or seals to close some
of the foam distribution holes while leaving open those desired. As the
foam enters the foam application chamber 112 a slight pressure drop can
occur and the foam application chamber 112 fills with the foam. The
pressure in this chamber is dependent upon many factors including the rate
of feed of foam thereto and the rate of uptake of the foam by the
substrate travelling across the nozzle orifice. The foam application
chamber 112 has a nozzle orifice whose width or slot opening is defined by
an upstream nozzle lip 102 and a downstream nozzle lip 100; as previously
indicated nozzle orifice adjusters 1(a) to 1(f) can be employed to adjust
the nozzle orifice width. These can be conveniently attached by
conventional clamping or bolting means to the fixed exterior chamber
walls. In treating the substrate with the foam the substrate travels
across the nozzle lips 100 and 102 and in contact with them. The angle
that the substrate makes with the nozzle lips will be discussed in detail
hereinafter.
Several configurations for the nozzle orifice adjusters are shown by 1(a)
to 1(f) inclusive. The nozzle orifice adjuster is generally installed so
that its upper end is parallel to or at the same height as the exterior
chamber wall. Its length is the longitudinal length of the foam applicator
head. Its width will vary since it is used to adjust the nozzle orifice
opening and the angle or angles that the end has to its height or
perpendicular plane can vary as will be discussed in detail hereinafter.
The drawing in FIG. 1 shows both the upstream nozzle lip 102 and the
downstream nozzle lip 100 comprised of the exterior chamber wall and
nozzle orifice adjusters 1(b) and 1(a) respectively, with the nozzle
orifice therefore being the distance or space remaining between 1(b) and
1(a). In a modification thereof in which the nozzle orifice adjusters are
not present, the nozzle orifice would consist of the distance or space
between the inside planes of the two fixed exterior walls of the foam
application chamber 112. In either instance the angles of the two nozzle
lips with the substrates must be taken into consideration. However, they
are not shown to scale in the figures.
The foam applicator head illustrated by FIG. 2 is one in which one exterior
longitudinal wall of the foam applicator chamber 212 is fixed and the
other exterior longitudinal wall is movable or adjustable so as to enable
adjustment of the nozzle orifice width or slot opening. While the figure
portrays the upstream nozzle lip 202 as the movable exterior longitudinal
wall, it is to be understood that the downstream nozzle lip 200 or both
the upstream 202 and downstream 200 nozzle lips could be movable. In this
figure the construction of the foam applicator head is similar to that
portrayed in FIG. 1 and consequently the discussion of the various
components and chambers in relation to FIG. 1 is equally applicable to
their equivalent parts in FIG. 2. The major difference existing between
FIG. 2 and FIG. 1 is the movable or adjustable exterior wall structure of
FIG. 2 and the presence of the adjustment clamp or other means for holding
said wall in the selected position. Not shown in FIG. 2 are the nozzle
orifice adjusters 1(a) to 1(f) that one may, in some instances, choose to
use. In some instances the foam applicator head portrayed in FIG. 2 can be
advantageously modified by the complete elimination of the upstream nozzle
lip 202 and the means 222 for retaining said lip at its selected position.
In such instances the foam application chamber 212 essentially comprises
the downstream lip 200, the foam distribution plate 204 and the two end
seals, with the substrate travelling across and in contact with the
downstream nozzle lip 200. The figure shows foam distribution chamber 206,
with foam inlet 208, foam distribution plate 204 and foam distribution
holes 210.
FIG. 3 represents a longitudinal side view of a foam applicator head taken
through the foam inlet 308, whose location is again portrayed in the base
thereof. The side view includes the end walls 314 and 316 and suitable
mounting means 318. Also shown is a manner in which the foam distribution
holes 310 are situate in the foam distribution plate 304. This side view
is representative of any foam applicator head portrayed in FIG. 1 or FIG.
2. The foam distribution chamber is 306 and the foam application chamber
is 312.
FIG. 4 and FIG. 5 are representative of the relative positions of the
upstream nozzle lip and downstream nozzle lip to each other and are
presented to facilitate discussion and understanding of the angles of the
lips and of the adjusters.
FIG. 4 shows a pair of nozzle lips 401 and 402 without nozzle orifice
adjusters attached thereto. In this FIG. 401 represents the upstream
nozzle lip and 402 represents the downstream nozzle lip. The width x of
the nozzle lip can be any suitable width desired. The distance y between
the two nozzle lips, the nozzle orifice, can be from 0.01 to about 6
inches, preferably from 0.25 to 1 inch, most preferably from 0.5 to 0.75
inch. Angle A can vary from about 15.degree. to about 90.degree.,
preferably from about 45.degree. to about 90.degree. and angle B can be
from about 15.degree. to about 135.degree., preferably from about
60.degree. to about 110.degree., most preferably about 95.degree.. It is
to be noted that angles A and B can be but need not be equal.
FIG. 5 shows a pair of nozzle lips with nozzle orifice adjusters attached
thereto. The entire unit 501 and 502 represents the upstream nozzle lip
wherein 502 is the nozzle orifice adjuster. The entire unit 503 and 504
represents the downstream nozzle lip wherein 503 is the nozzle orifice
adjuster. Components 502 and 503 would be the equivalents of 1(a) to 1(f)
inclusive of FIG. 1. The distance w between the two nozzle lips, the
nozzle orifice, can be from 0.1 to about 6 inches, preferably from 0.25 to
1 inch, most preferably from 0.5 to 0.75 inch. The widths of s and v can
be from 0.25 to 1 inch; the width of t can be from 0.1 to 4 inches, and
the width of u can be from 0.5 to 1.5 inches. Angle C can be from about
30.degree. to 90.degree., preferably about 45.degree.; angle D can be from
75.degree. to 90.degree., preferably about 90.degree.; angle E can be
from 30.degree. to 90.degree.; angle F can be from 75.degree. to
90.degree., preferably from 80.degree. to 88.degree., most preferably
85.degree.; and angle G can be from 45.degree. to 105.degree., preferably
from 45.degree. to 100.degree..
In FIG. 5 the upstream nozzle lip 501 plus 502 construction illustrated is
that in which a nozzle orifice adjuster, 502, has been attached to the
exterior wall, 501, of the foam applicator head. It is apparent that a
similar construction can be fabricated from a single piece wherein the
angles C, D and E are as hereinbefore defined. The same can be
accomplished for the downstream nozzle lip 503 plus 504.
In a typical operation, a liquid formulation is prepared containing the
functional chemical treating agent, frothing agent, wetting agent if
desired, and water. This formulation is frothed to a foam in conventional
commercially available foaming means and conveyed to the foam applicator
head via suitable conduit means. The foam enters the foam distribution
chamber via the foam inlet wherein a pressure equilibrium results as the
foam completely fills this chamber. Not shown in the drawings are means
for recycling foam and condensate and means for measuring pressure at any
point in the foam applicator head. As the foam distribution chamber fills,
the foam passes through the foam distribution plate into the foam
application chamber, rises and comes into contact with the substrate which
is travelling across the nozzle orifice and which is in contact with the
nozzle lip.
The angle of contact that the substrate makes with the inward taper of the
downstream nozzle lip has an effect on the uniformity of application and
the pressure drop observed across the fabric in the foam application
chamber. It was observed that use of a foam applicator head of the type
shown in FIG. 1 having a foam distribution chamber that measured 2 inches
wide, 2 inches high and 9 inches long and a foam application chamber that
measured the same but contained an adjuster 1(a) that was 0.75 inch wide
and tapered inwardly 5.degree. resulting in a nozzle orifice opening about
1 3/16 inch, exhibited the lowest pressure drop across the fabric, in
inches of water; whereas, the same foam applicator head in which the taper
varied above and below this angle showed a higher pressure drop across the
fabric. In all instances, however, uniformity, as evidenced by a tracer
dye, of the wash-wear treatment was good to excellent. The foam was
applied to 65/35/polyester/cotton at a fabric speed of 300 feet per minute
and at an add-on of 6 weight percent. The foam comprised a wash-wear
formulation containing 1,3-dimethylol-4,5-dihydroxy-2-imidazolidone and
had a foam density of 0.037 g/cc. The results are shown below:
______________________________________
Degree of Taper Pressure Drop
______________________________________
0 5.5
2 5
5 4
10 5
15 5.25
20 7
______________________________________
The apparatus of this invention can be used to treat any porous substrate
such as a textile fabric or a non-woven material, paper, leather or wood
veneer, with any of the functional chemicals that are normally used in
their treatment. Thus, the apparatus can be used to apply a flame
retarding composition, a waterproofing or water repellant composition, a
latex, a fabric softener, a lubricant, a hand builder, a dye or pigment
for coloring the fabric, a sizing agent, a whitening agent or fluorescent
brightener, a bleach, a binder for a non-woven fabric, a scouring agent, a
radiation curable or polymerizable monomer or polymer or oligomer, or any
other material that is normally used or applied to a fabric or similar
substrate. As previously indicated, use of the apparatus of this invention
permits one to apply the functional or treating chemical in the form of a
froth or foam to the surface of the material without employing
unnecessarily large quantities of water. In view of the escalating energy
costs and shorts supplies of natural gas and other fuels this is a
distinct advantage since less energy is required to dry the fabric for
further and subsequent treatment of the foam treated substrate.
In the use of the foam applicator head of this invention a functional
treating formulation or composition containing the functional reagent that
is to be added to the fabric is foamed in a foaming apparatus. The term
functional treating composition or variants thereof is used in this
application to define a formulated composition containing a reactive or
functional reagent that is used to treat a porous substrate such as a
fabric or paper to impart a desired physical or chemical property thereto.
These functional treating compositions are used to produce the foams
applied to the substrate with the foam applicator head of this invention
and contain the foaming agent, functional chemical, wetting agent, water
and other additives, as identified and in the concentrations hereinafter
set forth. The equipment used for producing a foam is well known and many
different types are commercially available. The composition, in the form
of a foam, is then conveyed to the foam applicator head where it is
transferred to the surface of the textile material that is to be treated.
The manner in which the foam is transferred to the textile material is
critical for uniform distribution on to the fabric. It has been found that
the manner in which the transfer is made, the specific density and bubble
size, and the stability of the foam are also important.
The foam is usually generated in commercially available foam generating
devices, which generally consist of a mechanical agitator capable of
mixing metered quantities of a gas, such as air, and a liquid chemical
composition containing the functional treating agent or chemical that is
to be applied to the fabric and converting the mixture to a foam. It has
been found that the density of the foam, its average bubble size and the
stability or foam half-life of the foam are important factors. The foam
density can range from 0.005 to 0.3 gram per cc, preferably from 0.01 to
0.2 gram per cc.
The foams generally have an average bubble size of from about 0.05 to 0.5
millimeters in diameter and preferably from 0.08 to 0.45 millimeters in
diameter. The foam half-life is from 1 to 60 minutes, preferably from 3 to
40 minutes.
The foam density and foam half-life are determined by placing a specified
volume of the foam in a laboratory graduated cylinder of known weight, a
100 cc or 1,000 cc cylinder can be used, determining the weight of the
foam in the cylinder, and calculating the density from the volume and
weight of the foam in the cylinder.
From the measured foam density and volume, and the known density of the
precursor liquor, the liquor volume which would equal one-half of the
total weight of the foam in the cylinder is calculated. The foam halflife
is the time for this volume of liquid to collect in the bottom of the
cylinder.
The foam bubble size is measured on a sample of foam taken at the
applicator nozzle and is determined by coating the underside of a
microscope glass slide with the foam, placing the slide on the microscope,
supporting the slide on each end by two slides, and photographing it at
once, preferably within 10 seconds, with a Polaroid camera at a
magnification of 32 fold. In an area of the photomicrograph measuring 73
by 95 mm, corresponding to an actual slide area of 6.77 square
millimeters, the number of bubbles is counted. The average bubble diameter
size in mm. is then determined by the equation:
##EQU1##
The formulated compositions used for producing the foam contain a frothing
or foaming agent at a concentration of about 0.2 to 5 weight percent,
preferably from 0.4 to 2 weight percent; the functional chemical at a
concentration of from about 5 to 75 weight percent, preferably from 10 to
60 weight percent, this being dependent upon the particular functional
chemical being employed, with water making up the balance of the weight of
the total composition. There can also be present, as an optional
ingredient, a wetting agent at a concentration of from about 0.001 to 5
weight percent or more, preferably from about 0.01 to 1.0 weight percent
of the total composition when the wetting agent is used. However, it need
not always be present and can in some instances be completely absent when
the foaming agent supplies sufficient wetting action.
As a frothing agent, one can use any surface active agent which will
produce a foam having the characteristics herein before described. The
composition is foamed in a conventional foaming apparatus to produce a
foam using air or any inert gaseous material. The amount of gas that is
used to foam the composition is generally about 5 times the volume of the
liquid composition that is to be formed and can be as much as 200 times or
more thereof. In this manner there is produced a foam having the desired
density and bubble size. The particular components used to produce the
foam are important in order to achieve a foam which will be readily
absorbed in a uniform manner by the substrate material and permit the
application of the desired amount of the functional chemical to the
substrate.
Illustrative of suitable foaming agents, one can mention the ethylene oxide
adducts of the mixed C.sub.11 to C.sub.15 linear secondary alcohols which
contain from about 10 to 50 ethyleneoxy units, preferably from about 12 to
20 ethyleneoxy units in the molecule. One can also use the ethylene oxide
adducts of the linear primary alcohols having from 10 to 16 carbon atoms
in the alcohol moiety, or of the alkyl phenols wherein the alkyl group has
from 8 to 12 carbon atoms, wherein the adducts can have from about 10 to
about 50, preferably from about 12 to 20 ethyleneoxy units in the
molecule. Also useful are the fatty acid alkanolamides such as coconut
fatty acid monoethanolamide. Another suitable class of frothing agents is
the group of sulfosuccinate ester salts, such as disodium
N-octadecylsulfosuccinate, tetrasodium
N-(1,2-dicarboxyethyl)-N-octadecylsulfosuccinate, diamyl ester of sodium
sulfosuccinic acid, dihexyl ester of sodium sulfosuccinic acid, dioctyl
ester of sodium sulfosuccinic acid, and the like. In addition to the
above, nonionic and anionic surfactants one can also use a cationic
surfactant or an amphoteric surfactant such as distearyl pyridinium
chloride, N-coco-beta-aminopropionic acid (the N-tallow or N-lauryl
derivatives) or the sodium salts thereof, stearyl dimethyl benzyl ammonium
chloride, the betaines or tertiary alkylamines quarternized with benzene
sulfonic acid. These are well known and any similar surfactant can be used
in addition to those specifically identified above. Blends of one or more
surfactants are often used to advantage. In selecting the foaming agent
for a particular formulation, care must be exercised to use those which
will not unduly react with the other reactants present or interfere with
the foaming or treating process.
As previously indicated a wetting agent also can be optionally present when
its presence is needed to produce a foam of the desired fast breaking and
wetting properties with sufficient stability to be pumped from the foam
generator to the applicator nozzle. The foams are semi-stable and fast
wetting and are produced from compositions containing the defined
components in relatively high concentration when compared to aqueous
treating compositions heretofore used. The stability of the foam produced
with these compositions must allow pumping of the foam from the foam
generator to the applicator head, but the foam must be readily broken and
rapidly absorbed when it reaches the substrate surface. The foam breakdown
characteristic is important, since retention of the foam or bubble
structure on the treated substrate surface can result in craters,
spotting, or otherwise uneven distribution on the substrate. In addition,
foam breakdown characteristics are important to facilitate recycle; any of
the known physical techniques, i.e. elevated temperature, mechanical
shear, etc,, can be used in the recycle step. In regard to foam breakdown,
the foams having the half-life defined have been found to possess the
desired combination of stability to facilitate pumping and delivery to the
substrate, and instability to facilitate fast wetting when contacted with
the substrate and ease of recycle.
The presence of the optional wetting agent is important when the foaming
agent used produces a stable foam but is a relatively poor wetting agent
with the consequence that the foam does not provide sufficient front to
back uniformity or penetrability for continuous high speed application to
the substrate. In such instances a combination of foaming agent and
wetting agent is used and illustrative of suitable wetting agents one can
mention the adduct of 6 moles of ethylene oxide with trimethyl nonanol,
the adducts of about 7 or 9 moles of ethylene oxide with the mixed
C.sub.11 to C.sub.15 linear secondary alcohols or with the C.sub.10 to
C.sub.16 primary alcohols, the adduct of 9 moles of ethylene oxide with
nonylphenol; the silicone wetting agents of the structure
##STR1##
wherein n has a value of 5 to 25, m has a value of 3 to 10, p has a value
of 6 to 20 and R is alkyl of 1 to 6 carbon atoms; also useful are the
commercially available fluorocarbon wetting agents such as the known
perfluoroalkylated surfactants.
The amount of such wetting agent to be added to provide for the fast
breaking and rapid absorption properties will vary depending upon the
particular wetting agent selected, however, this amount can be readily
ascertained by a preliminary small scale evaluation. Thus, it was observed
that the concentration of the fluorocarbon wetting agents is preferably in
the range of from 0.001 to 0.5 weight percent, and the range for the
silicone wetting agents is preferably from 0.01 to 0.3 weight percent. It
has also been observed that excessive quantities of the silicon or
fluorocarbon wetting agents may inhibit foam formation or shorten foam
stability to such an extent that pumping and delivery of foam to the
substrate is no longer feasible. Thus, a preliminary small scale screening
test will establish if such a problem exists in any particular instance.
As previously indicated, some foaming agents possess sufficient wetting
properties that there is no need for the use of the supplementary or
optional wetting agents. However, in most instances, better front to back
uniformity of treatment of the substrate is obtained using a mixture or
combination of foaming agent and wetting agent. It has also been observed
that the addition of a known foam stabilizer, such as hydroxyethyl
cellulose or hydrolyzed guar gum, can be of benefit, provided it does not
unduly affect the desired foam properties.
The foam applicator head of this invention can be used to apply any number
of functional or treating chemicals to a substrate to impart a particular
property or treatment thereto. Thus, it can be used to apply
flame-retarding reagents, waterproofing or water-repellant reagents,
mildew proofing reagents, bacteriostats, antistats, permanent press or
wash and wear compositions, softeners, lubricants, hand builders, dyes,
pigments, sizes, whitening agents, fluorescent brighteners, bleaches,
binders for non-woven fabrics, latexes, scouring agents, thermal or
radiation curable monomers or oligomers or polymers, soil or stain release
agents, or any other material known to be used in the treatment of
textiles or papers. Illustrative of typical functional chemicals one can
mention dimethyloldihydroxyethylene urea, dimethylolethylene urea,
dimethylolpropylene urea, urea formaldehyde resins, dimethylol urons, the
methylolated melamines, methylolated triazones; the methylolated
carbamates such as the ethyl or methoxyethyl or isopropyl or butyl
carbamates; the epoxides such as vinyl cyclohexene dioxide,
2,3-diallyoxy-1,4-dioxane, 2,3-bis(2,3-epoxypropoxy)-1,4-dioxane, the
diglycidyl ether of bisphenol-A, bis(3,4-epoxybutyl)ether; flame-proofing
agents such as tetrakis hydroxymethyl phosphonium chloride, polyvinyl
chloride latexes, (N-hydroxymethyl-3-dimethyl phospono)propionamide;
water-proofing or water repellant agents such as aluminum formate, sodium
formoacetate, methylene bis-stearamide, mildew proofing and bacteriostat
agents such as copper-8-quinolinolate, dihydroxydichlorodiphenylmethane,
zinc salts of dimethyldithiocarbamic acid, dihydroxymethyl undecylenamide;
latexes such as polyvinyl acetate latexes, acrylic latexes,
styrene-butadiene latexes; softeners such as emulsifiable polyethylene,
dimethyl stearate ammonium salts; lubricants such as butyl stearate,
diethylene glycol stearate, polyethylene glycol, polypropylene glycol;
hand buiilders such as polyvinyl acetate latexes, acrylic latexes,
styrenebutadiene latexes; dyes and pigments such as Acid Blue 25 (Color
Index 62055), Acid Red 151 (Color Index 26900), Direct Red 39 (Color Index
23630), Dispersed Red 4 (Color Index 40755), Phthalocyanine Blue 15 (Color
Index 74160); sizes such as polyvinyl alcohol, corn starch; whitening
agents such as 4-methyl-7-dethylaminocoumarine; bleaches such as sodium
hypochlorite, chlorine, hydrogen peroxide. dichlorodimethyl hydantoin,
sodium perborate; binders for non-woven fabrics such as ethylene-vinyl
acetate emulsion polymer, acrylic emulsion polymer, vinyl-acrylic
copolymer; scouring agents such as sodium lauryl sulfate, triethanolamine
lauryl sulfate, sodium N-methyl-N-oleoyltaurate, primary and secondary
alcohol ethoxylates; radiation curable monomers and oligomers such as
2-hydroxyethyl acrylate, neopentyl glycol diacrylate, pentaerythritol
triacrylate, isodecyl acrylate, acrylated epoxidized soybean or linseed
oil; antistatic agents such as ethoxylated stearyl amines; soil or stain
release agents such as acrylic polymers and fluorocarbon emulsions.
The foam compositions applied with the foam applicator head of this
invention are prepared by mixing the selected functional chemical, foaming
agent, wetting agent and water, with other conventional agents normally
present, in the amounts indicated. This formulation has a Brookfied
viscosity of from 0.5 to 75 cps, preferably from 1 to 50 cps at 25.degree.
C. The manner of preparing the formulation will depend upon the particular
functional or treating agent present and the procedures normally used for
preparing compositions containing the selected functional agent are
normally employed in producing our formulations. The formulation is then
foamed, the foam is conveyed to the foam applicator head and applied to
the surface of the substrate.
In producing the foam, a metered quantity of the formulation is introduced
to the foamer and foamed. The foaming step is controlled by adjusting the
volume of air introduced to the foamer and the rotation rate. in rpm, of
the rotor in the foamer. The rotor's rotation rate plays an important role
in producing a foam that will have the previously defined bubble size and
half-life. The relative rates of feed of the formulation and the gas will
determine the density of the foam. These facts are known to those skilled
in the art.
It has been found that when the width or gap of the nozzle orifice is of a
dimension such that the machine contact time is equal to or less than the
equilibrium contact time for the particular foam-substrate combination
that is being run, as defined by the equation MCT.gtoreq.ECT, good
application is achieved.
The machine contact time, abbreviated MCT, is the amount of time that any
given point of the substrate remains over the nozzle orifice during the
application of foam to the substrate. The machine contact time in seconds
is equal to the gap or orifice width in inches divided by the speed of the
fabric in inches per second. The equilibr | | |
