High solids ethylene acrylic acid aqueous dispersions and methods of producing same

A uniquely treated bead of ethylene acrylic acid (EAA) capable of forming a high solids aqueous dispersion in excess of 38% solids wherein the EAA may be prepared by either batch or continuous processes wherein the EAA is substantially fully reacted with ammonia, sodium or potassium in little or substantial absence of water, followed by a separate aqueous dispersion step, resulting in a unique and quick-drying dispersion material highly useful in coating, adhesive, laminating, ink and similar processes, and wherein operating expense and environmental concerns are at a minimum as a consequence thereof. The treated EAA may be prepared in a substantially dry to merely moist state for incorporation into an aqueous dispersion with high percentages of EAA having either higher or lower molecular weight with low viscosities as compared to heretofore.

BACKGROUND OF THE INVENTION 
Ethylene acrylic acid (EAA) is a ubiquitous substance with wide-ranging 
uses in industry and commerce. Among these multiferous uses is its 
incorporation into an aqueous dispersion after batch reaction for diverse 
coating and like purposes, as are well known in the art. 
Aqueous dispersions have significant advantages when used in the coating 
arts as compared to the common use of organic solvent dispersions and 
solutions, especially with respect to environmental, fire/explosive 
hazards, and pollution factors of organic volatiles and the significant 
difficulty and cost of collecting and satisfactorily handling the same 
during application and curing of the coatings. 
On the other hand, as noted further hereinafter, aqueous-based EAA coating 
materials, as heretofore available, have relatively high water content, 
which while explosive-safe and fume safe, require excessive and often 
unacceptable drying times, whereby in weighing the practical and economic 
merits of one against the other, the environmentally undesirable 
organic-based coatings have necessarily remained in widespread usage 
despite the increasing inveighment thereagainst. 
Such prior art teachings as to high mole ratio EAA dispersions are 
illustrated by the Dow Chemical patent to McCann et al U.S. Pat. No. 
3,799,901, the teachings of which are incorporated herein by reference. 
With respect to the Dow patent teachings as well as to present and indeed 
heretofore long-term availability of EAA aqueous dispersions, such 
dispersions are readily commercially available at 35% and 25% EAA solids 
proportion. The starting EAA bead resin therefor is available from various 
suppliers, including Dow Chemical Company under the trademark "Primacor" 
adhesive polymer utilizing beads identified as "5980" or "5990". Such 
beads are available in ammonia dispersions, as those known as "ADCOTE" of 
Morton Thiokol Chemical Corporation, with 25% EAA solids proportion using 
Dow Chemical "5980" beads (high molecular weight) or with 35% EAA solids 
using Dow "5990" beads (low molecular weight). In like manner, "YUKALON" 
EAA resin is available from Mitsubishi Chemical Corporation and is 
comparable to the Dow "5980" resin, while Dow Chemical itself has marketed 
"Primacor 4983" dispersion using the higher molecular weight "5980" beads, 
and "Primacor 4990" dispersion using the lower molecular weight "5990" 
beads. The availability and properties of these products are well known. 
When 5980-type beads are provided in such a 25% solids dispersion from 
these varied commercial sources, the EAA solids are of a size on the order 
of 500 A.degree. and the dispersion is water white in appearance, for 
example. Such resin as noted prior to incorporation into the dispersion is 
of relatively high molecular weight and melts at higher temperature. 
It is evident that such 25% dispersions with such a high water content 
present significant problems in coating and other applications with 
respect to reasonably efficient and rapid drying thereof, with severe 
demands of both time and heat input in an effort to accelerate drying 
without damage to the substrate in any way. 
As noted, a somewhat higher 35% solids proportion is available, wherein, 
however, the viscosity is substantially higher with resultant greater 
difficulty in effecting ready coatings therewith. The 35% dispersion of 
5990-type beads further is of lower molecular weight and with a lower 
melting point as compared to the 25% 5980-type dispersion, thereby 
handicapping the application of high-heat drying even if the application 
of the coating is successful. Such known materials, whether "25%" or "35%" 
in fact can not and do not feasibly serve as replacements for the unwanted 
organic EAA coatings, despite repeated efforts to utilize the same. It is 
important to note that a commercially usable 35% solids 5980-type 
dispersion cannot heretofore be successfully produced. 
Efforts to effect suitable dispersions of this type are taught in the 
aforesaid U.S. Pat. No. 3,799,901 of Dow Chemical Corporation, for 
example. It will be noted that while following the processes taught in 
that patent, it is stated that polymer solids as high as "40%" or "50%" 
may be employed. However, the resultant dispersions at these high solids 
levels are useless and totally unsuitable for any coating applications. 
Indeed, the same are described in that patent as "viscous paste" or "very 
viscous latex", and obviously cannot be employed for paper or other 
running length substrate coating. 
Prior to the present invention, for usable coating purposes and to achieve 
a serviceable low viscosity, the EAA solids concentration of necessity had 
to be lowered to about 25% or less, as with the aforesaid 5980-type beads, 
with resultant increase in water or liquid and unworkable heat 
requirements and drying times. Such also occurs with dilutions of the high 
solids "pastes" of the above-noted patent-taught processes. 
Accordingly, at the present time, EAA treated by known ordinary procedures 
for running coating operations, for example, is available only the order 
of 25% in aqueous dispersions. The techniques for doing so at the present 
time even to achieve this ratio are not efficient and indeed little more 
than individual batch processes incapable of quick or ready variation 
thereof as for incorporation of added constituents that may be desirable. 
Further, briefly stated, and with reference to the Dow patent, for example, 
the known batch techniques of producing even the presently available 25% 
and 35% dispersions are slow and inefficient as a result of excess 
quantities of water in bead preparation. Thus, illustratively, EAA beads 
are placed in a reactor with addition of water and substantial quantities 
of ammonia (i.e. 0.70 mole ratio ammonium hydroxide) to slowly react, 
resulting in an initital relatively highly viscous and relatively low EAA 
concentration aqueous dispersion. The reactor steps may be repeated as 
desired. Further, such reactor production thereof does not readily permit 
the controlled introduction of desired additives which are helpful in 
diverse coating formulations. 
While the exact nature of the reaction achieved by the present invention as 
discussed hereinafter is not precisely known, it is believed that the 
substantially different and markedly improved results are brought about by 
the introduction of substantially lower effective amounts of the ammonia 
directly to the EAA molecules in the significant absence of water. In this 
manner the ammonia targets reactor sites on the molecule in a manner that 
the prior art technique is incapable of achieving. 
The literature shows that ammonium hydroxide (NH.sub.4 OH), may be used to 
treat a carboxylic acid, resulting in an ammonium salt. In such prior art 
treatments, high EAA concentrations, approaching 35% solids and of 
flowable character, are unknown. Reference is made to a publication of Dow 
Chemical Company entitled "Separation of Ionomer Dispersions" from which 
it is clear that the use of high mole ratio hydroxides result in 
non-pourable gels and undigested EAA whenever high solids are sought, 
which materials are undesirable and all but useless. 
BRIEF SUMMARY OF THE INVENTION 
The present invention relates to the unique formulation of low viscosity, 
quickly driable and readily usable high solids EAA aqueous dispersions of 
38% solids or higher, as well as also the efficient production of such 
ethylene acrylic acid aqueous dispersions having a significantly high 
solids-to-water ratio, by special treatment of the EAA prior to dispersion 
preparation, which achieves unique and highly desirable results. 
The present invention, inter alia, in unique and novel manner, advances the 
teachings of the aforementioned Dow patent in major and significant 
respects. That is to say, in following the processes of that patent for 
high EAA solids contents, a virtually solid block of material results. It 
is a chief purpose of this invention to produce a low viscosity, low mole 
ratio, coatable aqueous dispersion having unique high EAA resin content. 
In the prior art, a high relative proportion of water along with an alkali 
salt as sodium or potassium, for example, is combined with the EAA in an 
effort to produce a latex, requiring relatively high proportions of 
ammonia for the reaction, resulting in a highly viscous product. With low 
mole ratios of the salt, say below 0.30 m.r., in an effort to reduce 
viscosity, there results substantial untreated, undigested bead material 
of the 5990 type, whereby the product is virtually useless. With higher 
mole ratios, i.e. 0.50 m.r. KOH, a thixotropoic solution results like a 
gel, and being thus unusable, must be diluted with water to about 10-15% 
solids to render the same pourable, whereby the exceedingly high and 
unwanted water content is therefore present. 
The instant invention embraces the discovery that minimal or low amounts of 
NH.sub.3 as NH.sub.4 OH (or alkali metal salts as KOH) should be provided 
to loosen up the EAA molecule in forming the dispersion, whereby the low 
volume NH.sub.3 can react fully with the EAA to produce a high reactant 
yield bordering on 100%. In this regard, then, much lower ammonia (or 
sodium or potassium salts) is employed than in the processes of the Dow 
patent, whereby the ratio of ammonia to EAA is far lower than contemplated 
or achieved in the teachings heretofore. 
As specially treated herein, the resultant EAA solids product may be as 
high as 95%-98% solids as initially reacted, but more commonly on the 
order of 45%-55%, and with high melting points as compared with the former 
prior art low-solids dispersions, whereby the products of the instant 
invention may be quickly and effectively dried with less heat input in 
view of the high solids level and with no coating or substrate damage. 
Further, the dispersions of the invention, notwithstanding the high-solids 
character thereof, are of sufficiently low viscosity so as to in no way 
impede ready application thereof to substrates. Further, especially in the 
case of Na ionomer, as an applied film, the treated EAA of the invention 
has superior engineering properties, as increased tensile strength, higher 
melting point, and with minimum or no pinholing. Further, ammonia 
treatment also results in similar enhanced properties. 
In addition, such unique relative concentration of invention-treated EAA, 
by reducing water bulk without loss of desirable application properties, 
facilitates ease of transportation and utilization in numerous and diverse 
industrial and commercial coating and and adhesive processes. 
Indeed, in producing a high solids EAA dispersion according to the present 
invention, the EAA product resulting from the inventive process can be 
sold in the form of beads, powder, flakes, or even gels, treated in 
accordance with the invention so as to be nearly "dry" to the industrial 
consumer, who then can add such water for dilution as may be required for 
specific application purposes, while still achieving low viscosity 38+% 
EAA solids content, with manifest advantages in shipping costs and 
versatility of usage, or fully prepared ab initio in dispersion for sale. 
According to the present invention, with respect to production of the 
treated EAA suitable for high concentration dispersion, the same can be 
prepared not only by individual batch processes, and may also be reacted 
continuously and delivered from an extruder, as a screw extruder. Such 
form of continuous preparation thereby provides in unique manner an 
ability to have a desired temperature control along the extruder barrel 
length, and wherein at selected locales therealong at differing stages of 
the reaction process, desired additives for reaction, color, filler, etc., 
may be successivelly introduced into the mix barrel before the final 
treated EAA extrudate emerges from the nozzle. 
In this manner, temperature and pressures can be readily controlled in a 
continuous production process. 
Indeed, with the specially treated EAA extrudate as prepared in an extruder 
in a substantially continuous basis, the extrudate can be sliced into 
chips or pieces of desired size, thereafter packed, and subsequently used 
when necessary by an end user by merely placing the chips into water for a 
short time, as 15-20 minutes, with appropriate agitation to achieve a 
desired high-solids dispersion as above noted for coating or other 
operations. 
Illustrative of that which is currently available are untreated EAA bead 
products of the Dow Chemical Company as aforementioned, identified as 
"Primacor" Dow 5980 (h.m.w.) and Dow 5990 (1.m.w.) beads. The 5980 beads 
when treated as in the aforesaid Dow patent and placed in dispersion 
(marketed as a "4893" dispersion) is called "water white" and has an EAA 
concentration of 25%, while the 5990 beads so treated result in a milky 
dispersion of a 35% concentration. These are the best known commercially 
usable dispersion products, and which are below the significant 
concentrations attained by the present invention. 
Dispersions made with treated EAA beads obtained by practice of the 
inventive treatment method herein, with both 980 beads and 5990 beads, 
have EAA concentrations in excess of 8%, which are not heretofore 
commercially known or thought capable of being successfully produced. The 
practice of the present invention not only achieves these surprisingly 
high concentrations, but also may do so with ease of production, ease of 
treatment modifications, ease of shipping, ease of handling, ease of 
drying and nominal-to-note toxic or environmental hazard concerns. 
The utility of the higher concentrations is especially important in the 
wide usage of aqueous EAA in diverse coating and adhesive compositions, 
for example. Thus, with an EAA concentration of 25%-35% in ordinarily or 
presently prepared aqueous dispersions as noted above, the significant 
water base greatly delays drying time of the applied coating and increases 
costs thereof, both in slower throughput and in increased and prolonged 
heat requirements. 
While EAA can be dispersed in organic carrier liquids resulting in a whole 
or partly organic-based coating or adhesive having significantly shorter 
drying time requirements than with water, environmental considerations 
involving organic and volatile vapors increasingly mandate, if feasible, 
far less pollution-prone water based carriers for coatings. 
Nonetheless, the invention also contemplates the useful incorporation, if 
desired, of small amounts of organic materials, as isopropyl alcohol (IPA) 
or N-methyl pyrrilidone (NMP), in low percentages in the initial unique 
treatment of the EAA beads to facilitate the reaction. 
As indicated, prior efforts to produce EAA aqueous dispersions following 
bead treatment in a batch reactor with ammonia and water struggle to 
achieve a barely serviceable and low 25% EAA density concentration, while 
prior preparation of a 35% EAA density, is in practical terms unusable, as 
contrasted with dispersions resulting from the special treatment of the 
EAA beads in the present invention, as aforesaid, nothwithstanding the 
common usage of water (H.sub.2 O) and ammonia (NH.sub.3) in both the prior 
art practice and the present unique inventive processes, by virtue of the 
sharply different methods of treatment. 
The product and process of the invention herein are also highly useful for 
inks as well as surface coatings, overall pinhole-free films, and 
laminating adhesives, as in film-film, film-foil combinations, for 
example. 
In all aspects of the invention unwanted organic solvents are avoided, in 
compliance with increasingly stringent environmental requirements.

DETAILED DESCRIPTION OF THE INVENTION 
The essence of the invention is the unique preparation of the EAA beads so 
that the same are capable of forming a high-solids aqueous dispersion that 
achieves the necessary coating characteristics yet with sufficiently 
reduced viscosity for ready and facile application, as on a web fed 
through a high speed rotary gravure press, for example, and with ease of 
drying without coating damage, as a function of the high-solids, high 
melting point, substantially less-water character of the dispersion. 
The EAA molecule includes ethylene groups which are difficult to solvate. 
To this end, a chief feature of the invention resides in the discovery of 
means for enhancing access to carboxylic acid receptor sites on the EAA 
molecule for reaction with ammonia (NH.sub.3) with a view toward solvating 
the ethylene. The resultant polymer product when dispersed in water, 
results in a dispersion having markedly lower viscosity at high EAA 
concentrations, heretofore unsuccessfully attained, and the necessary and 
desirable quick-dry characteristics and other practical engineering 
properties notwithstanding the high-solids nature thereof. 
Heretofore it had not been feasible to provide high-solids EAA aqueous 
dispersions greater than 35% solids of any practical utility, as 
above-noted 5990 ammonia-treated product, as the same is so viscous so as 
to be virtually incapable of flow or physical application as a coating on 
a substrate, or with inks, etc., while treated 5980 beads above 25% and 
towards 35% concentration becomes a non-flowing gel. There is also the 
problem of undigested, unreacted polymer in the prior treatment of 5980 
beads above 25% solids. 
By the inventive treatments herein, however, unique high-solids EAA aqueous 
dispersions may be provided which are highly serviceable and desirable, 
and are also liquid and flowable at such high concentration. As earlier 
noted, the novel treated EAA pellets or beads therefor may be produced by 
either a "batch" process in single charge reactors, or as a further 
feature of the invention by a "continuous" process as in largely 
conventional extruding equipment, per se, providing special aspects of 
reaction and control heretofore unknown. The essential aspects thereof are 
set forth hereinafter: 
(1) Batch Process Technique According to the Invention 
In the preparation of the EAA dispersion according to the invention in a 
basic batch process thereof, untreated EAA beads as procured from Dow 
Chemical or other manufacturers are placed in an airtight vessel in the 
substantial absence of water. 
In accordance with the invention, for example, a quantity of 0.25 mole 
ratio aqueous ammonium hydroxide (NH.sub.4 OH) is added to the EAA beads, 
and the substances are agitated, as by tumbling until a vacuum develops, 
wherein the ammonia is fully taken up by and reacted with the EAA beads. 
This very low mole ratio ammonia source compares with heretofore employed 
0.39 mole ratio ammonia to obtain maximum 35% solids with 5990 EAA beads, 
and with even higher 0.79 mole ratio ammonia used with 5980 beads to 
attain as much as 25% solids. 
The ammonia is preferably about 26.degree. Baum e aqueous ammonia. No 
externally provided heat is necessary, and the in-drum reaction between 
the EAA and the NH.sub.4 OH occurs at ambient temperature. During the 
treatment period, which may be for about two hours at room temperature, it 
appears that the aqueous ammonia is totally absorbed into the discrete EAA 
beads. In so doing, a substantial relative vacuum develops within the 
airtight vessel as the beads become ammoniated. The beads may partake of a 
slight color change. 
After a period of time, the vessel is opened and the treated beads, or 
now-ammoniated beads, are removed. It is important to observe that upon 
opening the vessel, there is no smell of ammonia (NH.sub.3) therefrom, 
which follows from the presumed absorption of the NH.sub.4 OH as noted 
above. 
After this reaction, water (H.sub.2 O) is slowly added to the treated beads 
in an open vessel to achieve a desired solids level. Illustratively for a 
level on the order of 39.5% solids, the water is added with agitation or 
stirring, and at this time external heat may be provided, as by a steam 
jacket to about 195.degree. F. or so. The reaction product is then 
permitted to cool, with light agitation. As a preferred option, the 
addition of the water is in a stepwise fashion, i.e. 1/3 H.sub.2 O, 
stirring, next third, stirring, the last third, and stirring. 
The solids level is tested for the final solids contents desired for the 
coating, adhesive, or ink application, and sufficient final water is 
admixed as necessary to obtain the desired high solids level, e.g. 38% or 
more. 
The resultant dispersion is then preferably filtered through increasingly 
fine mesh, as 20, 60, and 150 mesh, to remove any possibly unreacted 
pellets of EAA and any diverse unwanted fibers or detritus. 
Thus, in one instance, at about 150.degree. F., a sample made with h.m.w. 
beads was taken and found to be 38% EAA solids. Water was added to lower 
the solids to 35% at room temperature, and the dispersion had a viscosity 
sufficiently low to permit ready coating onto a substrate, a product 
heretofore unattainable. 
The resultant unique 35% treated h.m.w. solids dispersion produced 
according to the ammonia treatment form of the invention has numerous 
beneficial and desirable characteristics, including: 
(1) Minimal ammonia gas evolves or is driven off for the treated EAA 
product by virtue of the exceedingly low mole ratio above noted, thereby 
avoiding the cost and concern of environmentally objectionable excess 
ammonia fumes. 
(2) This product contains some 40% additional EAA solids with comparable 
reduction in water as compared with the hitherto highest available 25% 
solids dispersion with 5980-type beads, with more effective coating of 
substrates, yet with no adverse viscosity of production difficulties. 
(3) Drying or curing of the 38+% treated solids dispersion made according 
to the invention is on the order of one-third faster than the virtually 
unusable prior "4990" dispersion made from 5990 resin (low molecular 
weight of about 12,000) product noted above, with significantly less 
adverse effect on the substrate and energy consumption. Further, as 
indicated, a 35% solids product with the 5980 high molecular weight 
(18,000) resin was heretofore unattainable in any event. 
It is very important to note that while in the illustrative example the 
solids level is at 38% or more, the aqueous dispersion of the invention 
herein is eminently usable, with a relatively high melting point and a 
like molecular weight, which in actual fact contrasts sharply and totally 
with the virtually unusable 35% dispersion of the prior art treated beads, 
as well as the theoretically usable but in fact impractical 25% prior art 
dispersion for coating/adhesive and like purposes. 
Alcohol/OH.sup.- Modification Process 
In view of the relative unacceptability of the prior art EAA product 
because of unacceptable viscosity, long drying time, etc., efforts were 
made to enhance the same and lower viscosity of the dispersion by the 
addition of means other than water. Thus, in the prior art, isopropyl 
alcohol (IPA) has been added to the completed and reacted dispersion long 
after the EAA has been treated to make the same. In this prior art usage, 
the IPA is primarily to dilute the dispersion and permit somewhate 
speedier drying of the same when applied as a coating. No reaction occurs 
with the EAA when the IPA is used as a diluent in this manner. 
While reducing viscosity and enhancing drying, such use of the IPA 
introduces an unwanted alcohol or like organic volatile to cope with 
environmentally along with the gaseous ammonia noted earlier. 
According to the present invention, the treatment of the EAA may optionally 
and preferentially include the introduction of isopropyl alcohol (IPA) or 
NMP, as a source of organic solvating medium introduced in small quantity 
(i.e. 5% or less) directly to the EAA beads at the time of initial 
reaction and before completion therof, and provides differing results, 
namely smaller ultimate EAA particle size, and lower mole ratio 
requirements for the ammonia, as well as enhancing the reaction. The use 
of the alcohol or NMP in the present invention, then, is to enhance the 
reaction treatment, and not as a quick-dry addition to the dispersion 
proper effected subsequent to bead treatment. 
Further, limited introduction of such an organic additive, as for example 
NMP, IPA, or propylene glycol, permits the mole ratio of the NH.sub.4 OH 
to drop to as little as 0.25 or even 0.10, while yet resulting in the 
ability to produce as high as a 40.5% solids EAA dispersion with good 
viscosity and coating ability. 
This contrasts markedly with the teachings of the literature and the 
aforesaid Dow patent, which achieve only a 25% EAA solids result using the 
5980 resin reacted with a substantially higher mole ratio of ammonia, such 
as 0.70 mole ratio or higher. Similarly, the inventive results contrast 
sharply with the 35% solids product of the 5990 resin at the 0.35 or 
higher mole ratio ammonia source. 
The aforesaid relaxation of the EAA bead molecule is unnecessary with 
ammonia, which is capable of entering the bead and reacting with the acid 
sites therein, but has the advantage as noted of further reducing the 
amount of ammonia required. In the case of a caustic reaction as with NaOH 
or KOH, rather than ammonia, the use of the solvating additive is 
preferred to sufficiently relax the EAA molecule to expose the receptor 
sites for reaction. While IPA, NMP, and propylene glycol have been 
specifically mentioned, it would appear that any good solvating medium or 
chemical with solvating properties having an OH.sup.- group effective to 
expose the acid receptor sites in the EAA molecule before reaction would 
be desirable to permit the reaction with a salt or ammonia in accordance 
with the invention. 
(2) Continuous Treatment Process According to the Invention 
The present invention includes the capability of practicing the same on a 
generally continuous basis in contrast to a batch or single lot basis. 
Thus a substantially conventional twin screw mixing extruder may be 
provided into which substantially dry EAA beads are fed from a Banbury or 
other blade mixer for treatment. The screw extruder advances, and 
masticates the beads between the screw flights as the mass moves toward 
the discharge nozzle from which the in-extruder treated EAA issues in 
rodlike form. 
At one or more selected locales along the extruder length, NH.sub.3 is 
injected directly into the moving mass to react therewith prior to 
emergence from the extruder nozzle. The speed of the extruder and the 
locale or locales of NH.sub.3 introduction are selected so as to permit 
completion of the reaction prior to exit. In this regard, the extruder 
barrel can utilize conventional heating and cooling jackets therearound 
which are controlled as desired to effect the result. 
Ammonia in substantially gaseous form as NH.sub.3 may be introduced 
directly into the extruder and into the EAA polymer which will have trace 
water, producing a solid material at room temperature which is estimated 
to be substantially 100% ammonia salt of EAA polymer with only 
trace/catalytic amounts of water. This EAA solid can then be dispersed 
into hot water to obtain a desired concentration suitable for coating at 
any lower level, but including the higher levels of 40%-55% which permits 
ease of coating application coupled with rapidity of drying of the coating 
on the substrate. 
In like manner, isopropyl alcohol and water may be injected directly along 
the treated barrel, the rodlike material emerging from the nozzle at a 40% 
or higher solids ratio, then being cut or fractured as necessary and 
blended with added water to attain the desired solids level for coating 
purposes. 
The basic technique to achieve a high EAA concentration according to the 
invention is to take the EAA polymer in free acid form, melt and masticate 
the same as in a heated extruder, and then incorporate and react ammonia 
in gaseous form along with a minimum of water as necessary. In this 
manner, the ammonia is trapped in the EAA which is substantially a solid, 
after which the reacted product can be easily and quickly converted to a 
desired dispersion concentration. 
This contrasts sharply with prior art techniques of effecting batch 
fabrication of EAA dispersions with high concentrations of NH.sub.4 OH and 
water in a reactor wherein 25% to 35% concentrations of EAA are the best 
practically obtainable. The excess of NH.sub.4 OH present in the standard 
prior art dispersions, made as from the aforementioned Dow 5880 and 5980, 
is evident when on drying the EAA coatings made from the prior art process 
to produce the residual film, substantial NH.sub.3 is driven off, and 
wasted or recovered from the atmosphere at additional cost. By the instant 
invention, the use of ammonia is reduced on the order of one-half, with 
attendant obvious benefits in all respects. 
In the prior art practice, as noted, substantial quantities of water, 
ammonium hydroxide, and EAA beads are admixed and reacted in a reactor 
vessel substantially simultaneously. Specifically, to a quantity of water 
in the reactor or other vessel, the ammonium hydroxide and beads are 
added, the vessel closed, and appropriate heat and agitation supplied. 
In the invention herein, however, the EAA beads and the ammonia (or sodium 
as NaOH or potassium as KOH) are admixed with only nominal water, namely 
only that required to carry the reactant, with no additional water. This 
may be effected as desired, but a preferred and efficient manner is in an 
extruder, wherein the location, timing, and temperature of ingredients, 
especially the NH.sub.4 OH, can be precisely controlled, and in the 
absence of additional water. In this regard, the enhancing additive having 
an alcohol OH.sup.- radical, as IPA, propylene glycol, etc., for example, 
when extruder-processed, may be controlled and barrel-introduced prior to 
introduction of the principal reactant to the EAA. Alternatively, the 
beads may be treated with the OH.sup.- additive before being introduced 
into the extruder barrel. 
Illustrative Test Results 
A series of tests were performed which demonstrate the unique factors 
entering into the invention. In each test, a quart bottle was filled with 
exactly 300 grams of EAA beads. 
Test 1: (Prior Art) 
39.3 grams of water were added, and the bottle was agitated at room 
temperature by rolling for 1 week. The agitation is generally comparable 
to that of a Sigma mixer or a ribbon blender. 
After one week, and after additional extended periods of time, the water 
was still present, with no significant absorption into the EAA beads. 
Essentially, water is repelled by the EAA beads under such conditions, as 
is known in the art. 
Test 2: 
In this test, 5% by weight IPA alone was added, the IPA being substantially 
entirely free of any water. 
In approximately one half-hour, all liquid (the IPA) was entirely absorbed 
by the beads. The beads were somewhat swollen in size. 
Test 3: 
In this Test, no free water was provided, and a 0.26 mole ratio of a 25% 
solution of NaOH along with about 45 grams IPA added at the same time, 
with similar agitation. No heating was provided. 
In this instance, all liquid was absorbed into the beads after one day, and 
no free water whatever was visible. The beads were somewhat swollen in 
size. 
The resultant material in aqueous dispersion provided an excellent coating, 
with very good reflectivity, a harder surface and a higher melting 
temperature than presently known. 
Test 4: 
In this test, similar to Test 2, 15% NMP was added, and comparable results 
were attained as in Test 2. 
Test 5: 
In this test, 26.degree. Baum e aqua ammonia was added to the EAA without 
any additional water. The results were comparable to test 3, including the 
highly desirable dispersion and coating qualities and characteristics. 
With the beads penetrated and softened by the additive, thereby relaxing 
the EAA molecule to expose the acids groups, and with the water absorbed 
as in Test 2, the ammonia attacks the receptor sites of the EAA molecule 
to effect the reaction. 
Generally it appears that alkaline materials will achieve this result. 
Sodium, as in NaOH is effective, as is anhydrous or aqueous ammonia. 
Potassium as in KOH, would achieve similar results, and other alkaline 
metal bases as LiOH, etc. Similarly, other amines are operative. 
In the prior art, EAA beads were in an environment of high water content, 
at which time NH.sub.3 was added to effect the desired site reaction in 
the EAA molecule. With such excess amounts of H.sub.2 O present, the 
amount of ammonia to overcome the presence of so much water in accessing 
the EAA reaction sites is so great that the resultant reactant product was 
solid, nearly solid, or so highly viscous so as to be unusable in 
practical terms, as the material would utterly incapable of reasonable 
flow, let alone the low viscosity flow necessary for use in higher speed 
coating equipment. 
The product of the instant invention, by contrast, provides a high solids 
EAA coating material which is suitable for use with high-speed coating 
equipment, which results in a substantial savings of time, energy and 
resulting production costs. 
The properties achieved in EAA materials made in accordance with this 
invention are evident in the table of test results below. Overall superior 
coating and physical properties with ease of manufacture of the aqueous 
dispersion are achieved. Illustratively, substantial increas in tensile 
yield and much lower relative viscosity with ready pourability and 
substantially lower drying times accompany the high solids content of the 
dispersions of the invention. 
ILLUSTRATIVE SOLIDS DISPERSIONS MADE BY THE INVENTION 
______________________________________ 
Sample A.sup.1 
Sample B.sup.2 
Sample C.sup.3 
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Ultimate Tensile, PSI 
2160 2812 1848 
Tensile Yield, PSI 
643 2751 1879 
Secant Modulus 2% PSI 
2360 2750 1950 
Elongation, % 558 283 252 
Surface Tension 
38 37 34 
(dyne/cm) 
Vicat Softening, .degree.C. 
43 46 50 
Melting Point, DSC, .degree.C. 
77.7 79.1 77.3 
Hardness, Shore D 
40 49 46 
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Legend: 
.sup.1 34-35% ammonium salt solids dispersion made from "5980" resins, 
heretofore unattainable. The ammonia is entirely driven off. 
.sup.2 38% solids ionomer dispersion made from "5980" resins partially 
neutralized with .25 mole ratio NaOH, heretofore unattainable. There is a 
Na residuum. 
.sup.3 38% solids ionomer dispersion made from "5990" resins and with .25 
mole ratio NaOH, heretofore unattainable with this lower molecular weight 
polymer.