Textile sizes containing ultrafine-sized aqueous polymeric dispersions

A textile sizing composition comprising one or more aqueous-based dispersions containing between about 15 and about 50 percent by weight solids wherein said solids comprise one or more polymers derived from one or more ethylenically unsaturated monomers, said solids having an average particle size of less than 100 nanometers is disclosed.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to the use of extremely fine-sized aqueous 
polymeric dispersions, and particularly acrylic-based dispersions having a 
mean particle size of less than 60 nanometers as textile sizes. More 
specifically, the invention comprises the use of two or more fine-size 
aqueous dispersions which when combined together, optimizes the benefits 
of each dispersion to yield a final product which may be directly applied 
to natural and synthetic fibers. 
2. Technology Description 
Heretofore, numerous emulsion latexes have existed. However, the particle 
sizes of such latexes have generally been large, for example 120 
nanometers or larger. Moreover, the use of ultrafine sized latexes as 
textile sizing agents has not been appreciated. 
U.S. Pat. No. 4,177,177 to Vanderhoff et al relates to various methods for 
making polymeric emulsions which can be utilized to produce latexes. The 
latexes generally have a particle size greater than 100 nanometers. 
U.S. Pat. No. 4,228,047 to Pippin et al relates to an aqueous coating 
composition comprising a copolymer of at least 95 percent by weight of 
vinyl acetate and at least 0.1 percent by weight of maleic anhydride which 
allegedly has been found to have improved starch binder compatibility. 
Japanese Disclosure No. 52103588 to Asahi Dow relates to a carpet-backing 
composition containing 100 parts by weight (as solids content) of a 
copolymer latex: 200 to 350 parts by weight of inorganic filler and 
thickener consisting of 30-60 weight percent of a) butadiene: 20-70 weight 
percent of b) styrene 5-30 weight percent of c) methyl methacrylate: and 1 
to 5 weight percent of d) ethylene series of unsaturated carboxylic acid 
and has an average particle diameter of 60 to 120 nm. By using the latex 
of small particle diameter for the carpet backing, blistering is 
prevented. 
Belgian Patent No. 812139 to DeSoto, Inc. relates to opaque coatings 
obtained from a latex comprised of an aqueous suspension of small and 
large resin particles, the large particles having a Tg less than the small 
ones and having an average diameter which is greater than twice that of 
the small particles, the latter forming 20 to 65 weight percent of the 
total particles. The particles are such that neither the large nor the 
small ones can, on their own, coalesce when the latex is dried, to form a 
non-cellular film. The small particles actually give a powder under such 
conditions. The small particles are preferably polystyrene and the large 
ones a copolymer of vinyl acetate and an ester of a 4 to 18 carbon atom 
alkanol and an unsaturated carboxylic acid. The composition contains a 
minimum amount of solvent and rapidly gives an opaque coating of low 
porosity upon drying. It may be used for lipstick, crayons, etc. 
British Patent No. 1,100,569 to the Dow Chemical Co. relates to acrylic 
polymer latexes containing large and small particles prepared by 1) 
heating water containing a soluble catalyst to up to 85.degree. C. in an 
inert atmosphere, 2) adding 1/3 of a mixture of monomers, 3) carrying on 
the polymerization for at least 15 minutes, 4) adding an aqueous solution 
of an anionic emulsifier and an aqueous solution of the polymerization 
catalyst, and 5) adding the remaining monomer continuously over a period 
of at least 45 minutes. 
U.S. Pat. No. 3,711,435 to DuPont and Co. relates to a stable, aqueous 
colloidal dispersion prepared by mixing 1) a copolymer of 20 to 80 weight 
percent ethylene and 80 to 20 weight percent of an aminoalkylacrylate; 2) 
an acid having a dissociation constant of 10 to 5; and 3) water in 
proportion to give a solids containing 5 to 30 weight percent and a degree 
of neutralization of the amino groups of the polymer of at least 40 
percent. The mixing is effected at a temperature suitable for dispersing 
the polymer in particles of size less than 10 nanometers. The resulting 
dispersions have very small particle sizes so that they may be thinly 
spread over aluminum substrates to give void free coatings, and as 
flocculants for removal of suspended matter from water. 
N,N-dimethylaminoethylmethacrylate is a suitable comonomer. 
Japanese Disclosure No. 52-123478 to Kurraray relates to compositions 
prepared by emulsion polymerization of unsaturated monomers in the 
presence of a protective colloid which is prepared by cleaving 
water-solubilized copolymers in the presence of free radicals and by 
heating. The compound contains units of maleinimide and/or N-substituted 
maleinimide and units of alpha-olefin as essential components of the main 
chain. 
An article by Ugelstad, El-Aasser, and Vanderhoff, Journal of Polymer 
Science, Polymer Letters Edition, 11, 503:1973 relates to the production 
of latex particles by mini-emulsion polymerization of a mixed-emulsifier 
system including a surfactant and a long-chain alcohol or alkane 
cosurfactant utilizing ultrasonification. 
An article by Atik and Thomas, Journal of American Chemical Society, 103, 
4279: 1981 relates to aqueous styrene polymer microemulsions made by bulk 
polymerization having a number average particle size of from about 20 to 
about 35 nanometers by utilizing a mixed emulsifier of 
cetyl-trimethylammonium bromide and hexanol followed by polymerization 
with an oil soluble azobisisobutyronitrile and irradiation. However, the 
solids content was very low, less than 2 percent and the amount of 
emulsifiers utilized was approximately 1.5 times the amount of polymer by 
weight. 
An article by Jayakrishnan and Shah, Journal of Polymer Science, Polymer 
Letters, 22, 31 984 relates to a bulk polymerization of polystyrene or 
methyl methacrylate microemulsion particles having a number average size 
of from about 10 to about 60 nanometers utilizing sodium 
dihexylsulfosuccinate and ethylene oxide-propylene oxide block copolymers 
as mixed-emulsifiers and an oil soluble initiator such as benzoyl 
peroxide. However, the weight ratio of the emulsifier to the monomer was 
approximately one to one and the microemulsion could not be diluted with 
water. 
Canadian Patent Application No. 2,013,318, assigned to B. F. Goodrich is 
directed to a process for producing very fine-sized aqueous polymeric 
microemulsions. The process utilizes incremental addition of a monomer 
feed solution into an aqueous solution including one or more emulsifying 
agents and one or more water soluble or redox initiators. While this 
method may be used to produce such microemulsions, it is deficient in that 
the emulsion tends to discolor and that it is extremely difficult to 
obtain emulsions having a narrow particle size range profile. This 
reference suggests that the emulsions are suitable for use in paper 
production as a strength agent or an opacity improver. Other suggested 
uses include pigment binding, adhesives, binders for clay coatings, 
nonwoven saturations, textile coatings, beater addition polymers and 
binders for paint. 
An article by Okuba et al, "Preparation of Asymmetric Polymer Film by 
Emulsion Blend Technique", Colloid & Polymer Science, 268:1113-1117 
(1990), teaches blending two different particle size emulsions together to 
determine the tackiness properties of such blends. One of the starting 
emulsions disclosed is a poly(ethyl acrylate-methyl methacrylate) emulsion 
having a particle size of 0.02 microns. According to the article, this 
emulsion is prepared by combining the monomers in a glass flask with 
water, sodium sulfite, potassium persulfate and sodium dodecyl sulfate. 
The order or method of addition of the different reactants, initiators and 
emulsifiers is not specified. 
European Published Patent Application No. 0 429 207, assigned to Rohm & 
Haas is directed to a method of treating or coating a substrate with an 
aqueous composition. The coating composition is an aqueous dispersion of 
copolymer particles having mutually incompatible phases and having an 
average particle size of about 20 to about 70 nanometers. The dispersion 
is prepared by emulsion polymerization techniques. In preferred 
embodiments, the particles are of a core/shell morphology where the core 
has a T.sub.g of at least 45.degree. C. and the shell has a T.sub.g of 
lower than 35.degree. C. 
In commercial textile sizing operations, a sizing agent is applied to 
filament yarns to temporarily bind them together. This process inevitably 
involves applying an acidic material in a first pass to the yarns. 
Thereafter, the material is then neutralized by the addition of a base. 
This operation is both costly, as it requires the application of a 
multiple number of chemicals, and requires action to remove residual base. 
Despite the above teachings, there still exists a need in the art for a 
textile size material derived from one or more ultrafine sized emulsions 
and which may be directly appled to textile fibers without requiring 
neutralization with base. 
SUMMARY OF THE INVENTION 
In accordance with the present invention, a process for using one or more 
ultrafine sized emulsion latexes which does not discolor, has a narrow 
particle size distribution, is easily reproducible, and utilizes a minimal 
amount of surfactant as a textile size is provided. The process is 
particularly characterized by directly applying the one or more of the 
ultrafine sized emulsion latexes nanolatices to textile fibers without 
requiring neutralization of the emulsion latexes before application. 
One embodiment of the invention provides a textile sizing composition 
comprising one or more aqueous-based dispersions containing between about 
15 and about 50 percent by weight solids wherein said solids comprise one 
or more polymers derived from one or more ethylenically unsaturated 
monomers, said solids having an average particle size of less than 100 
nanometers. 
A particular preferred embodiment comprises a blend of ultrafine sized 
dispersions. The polymer of the first dispersion has a glass transition 
temperature of less than -25.degree. C. and the polymer of the second 
dispersion has a glass transition temperature of greater than -10.degree. 
C. Use of the two component system maximizes the benefits of the low glass 
transition temperature polymer, which is used to glue together filament 
yarn, while additionally maximizing the benefits of the higher glass 
transition temperature polymer, which apparently migrates to the outer 
surfaces of the sizing agent, giving a hard, non-tacky shell. 
Another embodiment of the present invention comprises a process for sizing 
textile fibers comprising the step of applying the above described textile 
sizing composition to a natural or synthetic textile fiber. 
Accordingly, an object of the present invention is to provide a novel 
textile sizing composition. 
Another object of the present invention is to provide a process for 
applying a novel textile sizing agent to natural or synthetic fibers. 
These, as other objects, will readily be apparent to those skilled in the 
art as reference is made to the detailed description of the preferred 
embodiment. 
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
In describing the preferred embodiment, certain terminology will be 
utilized for the sake of clarity. Such terminology is intended to 
encompass the recited embodiment, as well as all technical equivalents 
which operate in a similar manner for a similar purpose to achieve a 
similar result. 
The ultrafine sized latex textile sizing compositions are preferably 
produced by incrementally adding one or more ethylenically unsaturated 
monomers capable of polymerizing in an aqueous environment and 
incrementally adding a polymerization initiator to a reaction vessel 
containing water and one or more surfactants and allowing the one or more 
ethylenically unsaturated monomers to polymerize such that the average 
particle size of said polymerized monomers is less than 100 nanometers. 
The term "incremental addition" defines any form of addition of a small 
amount of the total monomer and/or initiator to the aqueous solution over 
an extended period of time until all of the monomer and initiator 
solutions have been added. This includes cyclic additions, interrupted 
additions, combinations of the above and the like. Preferably, the 
addition of the monomer and initiator is continuous and at a constant 
level over a period of time. Any ethylenically unsaturated monomer which 
is capable of polymerizing in an aqueous environment and potentially 
useful as a sizing agent may be selected as a starting material. 
Particularly preferred are any of the following monomers: (meth)acrylic 
based acids and esters, acrylonitrile, styrene, divinylbenzene, vinyl 
acetate, ethylenically unsaturated carboxylic acids, acrylamide, 
methacrylamide, vinylidene chloride, butadiene and vinyl chloride. The 
dispersion solids that are produced may take the form of homopolymers 
(i.e., only one type of monomer selected) or copolymers (i.e., mixtures of 
two or more types of monomer are selected; this specifically includes 
terpolymers and polymers derived from four or more monomers). 
Most preferred are the use of acrylic based acids and esters. The acrylic 
polymers of the present invention are derived from one or more acrylate 
monomers having the formula 
##STR1## 
where R.sub.1 is preferably hydrogen or an alkyl group having from 1 to 4 
carbon atoms and R.sub.2 is hydrogen or an aliphatic group having from 1 
to 20 carbon atoms. In most preferred embodiments, R.sub.1 comprises a 
methyl group and R.sub.2 is an alkyl group having from 1 to 20 carbon 
atoms. 
Specifically useful monomers falling within the scope of formula (I) 
include methyl methacrylate, ethyl acrylate, butyl acrylate, methacrylic 
acid, acrylic acid and mixtures thereof. 
Other monomers or starting compounds which may be utilized to produce 
ultrafine sized latexes are well known to the art. Examples are set forth 
in The Encyclopedia of Chemical Technology, Kirk-Othmer, John Wiley & 
Sons, Vol. 14, pp 82-97, (1981). To the extent necessary, this passage is 
hereby incorporated by reference. 
When producing copolymers that are in part derived from acrylic monomers, 
the amount of acrylic monomer typically ranges from about 30 to about 99 
percent of the total amount of monomers, with amounts ranging from about 
50 to about 90 percent being more preferred, and amounts ranging from 
about 60 to about 80 percent being most preferred. In addition, when 
copolymerizing with an acid, such as methacrylic acid, the copolymer may 
include up to 60 weight percent of acid. This is much higher than prior 
art systems which were limited to no more than 25% methacrylic acid and 
enables the latexes to be particularly useful as the resulting materials 
are easier to dissolve in base. Further, when producing copolymer 
dispersions, the separate monomers may be fed to the aqueous reaction 
medium from either the same or different feed vessels. 
In accordance with a particularly preferred embodiment of the present 
invention, the production of a novel textile sizing agent composition 
derived from two ultrafine dispersions is specifically provided. Such a 
composition comprises a mixture of two aqueous-based dispersions where the 
glass transition temperature of the polymer of the first dispersion is 
less than -25.degree. C., more preferably less than -35.degree. C. and the 
glass transition temperature of the polymer of the second dispersion is 
greater than -10.degree. C. and preferably less than 130.degree. C., more 
preferably less than 60.degree. C. In preferred embodiments, the 
respective weight amounts of the first dispersion to the second dispersion 
ranges from about 30:70 to about 90:10. Further, in accordance with a 
specifically preferred embodiment, the solids of the first dispersion are 
derived from butyl acrylate and acrylic acid and other acrylate, 
methacrylic and vinyl monomers which are polymerizable via free radical 
initiation; while the solids of the second dispersion are derived from 
methyl methacrylate and methacrylic acid and other acrylate, methacrylic 
and vinyl monomers which are polymerizable via free radical initiation. 
However, almost any polymer blend can be used; the key criteria being the 
difference in the glass transition temperature of the respective polymers. 
Under this arrangement the softer (low glass transition temperature) 
polymer is used to glue together filament yarns while at the same time the 
harder (higher glass transition temperature) polymer is used as a 
migratory additive (detacking agent) that can eliminate surface tackiness 
and blocking associated with the soft polymer. During the sizing 
operation, the softer polymer forms "spot-welds" between the yarn fibers 
whereas the harder polymer apparently migrates to the outer surfaces of 
the "spot-welds", giving a hard, non-tacky shell. Also within the scope of 
this invention is the combination of a ultrafine sized latex with a 
conventional sized latex (&gt;100 nm) for use as a textile sizing agent. 
While not necessary, it may be desirable that the polymers produced be 
cross-linked. This is accomplished by adding one or more cross-linking 
agents to the reaction medium. Examples of cross linking agent include 
monofunctional compounds such as N-alkylol amides of the formula 
##STR2## 
where R.sub.3 is an alkyl group having from 1 to 10 carbon atoms, 
preferably from 1 to 4 carbon atoms; R.sub.4 is hydrogen or an alkyl group 
having from 1 to 10 carbon atoms, preferably from 1 to 4 carbon atoms; and 
R.sub.5 is hydrogen or an alkyl group having from 1 to 4 carbon atoms. 
Specific examples of suitable cross-linking agents include N-methylol 
acrylamide, N-ethanol acrylamide, N-propanol acrylamide, N-methylol 
maleimide, N-ethylol maleamide, N-methylol maleamic acid, N-methylol 
maleamic acid esters, the N-alkylol amides of the vinyl aromatic acids 
such as N-methylol-p-vinyl benzamide, and the like. Another useful 
cross-linking agent is N-(isobutoxymethyl) acrylamide. 
Various difunctional compounds or monomers can also be utilized as 
effective cross-linking agents. These include compounds containing two 
olefinic groups such as divinylbenzene, divinylnaphthalene, 
divinylcyclohexane, and the like; various diacrylate or dimethacrylate 
esters of aliphatic diols where the ester portion has from 1 to 10 carbon 
atoms, and is preferably alkyl where the diol portion has from 2 to 8 
carbon atoms. Examples of these materials include ethylene glycol 
dimethacrylate, diethylene glycol diacrylate, diethylene glycol 
dimethacrylate and butylene glycol. 
Other cross-linking agents are described in the Journal of Applied Polymer 
Science, Vol. 34, pp 2389-2397 (1987) John Wiley & Sons, Inc., in an 
article entitled "New Cross-Linking Agents for Vinyl Polymers". To the 
extent necessary, this article is hereby fully incorporated by reference. 
The amount of the cross linking agent when utilized is generally from about 
0.05 to about 10 percent by weight, desirably from about 0.1 to about 5 
percent by weight, and most preferably from about 0.1 to about 1.0 percent 
by weight based upon the total weight of all monomers added. 
Also incrementally added to the aqueous reaction medium is one or more 
polymerization initiators, preferably a free radical thermal initiator. 
The polymerization initiator may take the form of many known initiators 
such as azo, peroxide, persulfate and perester initiators and may be 
either water soluble or monomer soluble. The amount of initiator added to 
the solution typically ranges from between about 0.05 to about 2 weight 
percent of the emulsion with amounts ranging from about 0.1 to about 1.0 
weight percent being particularly preferred and amounts ranging from about 
0.1 to about 0.5 weight percent being most preferred. The free radical 
initiator added is preferably an azo (azobisnitrile) type initiator (water 
or oil soluble) such as 2,2'-azobis-isobutyronitrile, 
2,2'-azobis-(2-methylpropanenitrile), 
2,2'-azobis-(2,4-dimethylpentanenitrile), 
2,2'-azobis-(2-methylbutanenitrile), 
1,1'-azobis-(cyclohexanecarbonitrile), 2,2'-azobis-(2,4-dimethyl-4-methoxy 
valeronitrile), 2,2'-azobis-(2,4-dimethylvaleronitrile) and 
2,2'-azobis-(2-amidinopropane) hydrochloride. 
Other free radical initiators which may be selected include peroxide 
materials such as benzoyl peroxide, cumene hydroperoxide, hydrogen 
peroxide, acetyl peroxide, lauroyl peroxide, persulfate materials such as 
ammonium persulfate, and peresters such as t-butylperoxypivalate, 
.alpha.-cumylperoxypivalate and t-butylperoctoate. 
Examples of commercially suitable initiators which may be selected include 
Wako V-50, Vazo 52, Vazo 64, Vazo 67 and Lupersol 11. These commercial 
initiators may be included with the monomer feed. 
In the case of water soluble initiators, such as the peroxides and 
persulfates, it is preferred that during polymerization the ionicity of 
the reaction medium be maintained at a constant. This is accomplished by 
removing a portion of the water from the aqueous reaction medium and 
adding this removed water to the initiator feed stream. The need for 
maintaining a constant ionicity is seen when attempting a conventional 
post treatment for residual monomer with ammonium persulfate and sodium 
metabisulfite. Large quantities of coagulum form, reducing the efficacy of 
the process. Similarly, a conventional initiator feed consisting of 
ammonium persulfate and 1-3 weight percent of the total water volume will 
cause agglomeration of polymer particles throughout the initiator 
addition. 
It has been found that by maintaining a constant ionicity in the reaction 
mixture, agglomeration can be avoided, yielding a more uniform particle 
size emulsion. By diluting the water soluble initiator with the proper 
quantity of water, the ionic strength of the initiator system will be the 
same as the contents of the reaction vessel at any time during the 
reaction/initiator feed. Presumably, this matched ionicity (as expressed 
in the number of charges per volume) allows the diffusion controlled 
migration of charged species such as ammonium persulfate and ionic 
surfactants from droplet to reaction mixture or vice versa. 
Use of highly concentrated initiator solutions presumably allows large 
changes in the ionic concentration in the area immediately surrounding an 
initiator droplet. It is hypothesized that this massive change in charge 
density overwhelms the stabilizing forces exerted on the particles by 
surfactant and initiator residues. 
The same ionic balance can be achieved by careful selection of a charge 
neutral monomer soluble initiator such as the azo type initiator 
commercially sold as VAZO 52 (2,2'-azobis-(2,4-dimethylvaleronitrile)) or 
VAZO 64 (2,2'-azobis-isobutyronitrile). In these cases, the entire 
quantity of initiator is contained within the monomer feed. 
In accordance with the process of the present invention, to produce the 
novel textile sizing compositions the monomer(s) and initiator(s) are fed 
into an aqueous reaction medium which comprises water and at least one or 
more emulsifiers. The emulsifiers are generally surfactants and hence can 
be cationic, nonionic, anionic, amphoteric, copolymerizable surfactants 
and the like with anionic generally being desired. Generally, the type of 
emulsifiers utilized are those which can be utilized in conventional latex 
polymerizations. As is recognized by one skilled in the art, a key 
criteria for selecting a surfactant is its compatibility with the 
initiator. 
Examples of suitable amphoteric surfactants include the alkali metal, 
alkaline earth metal, ammonium or substituted ammonium salts of alkyl 
amphocarboxy glycinates and alkyl amphocarboxypropionates, alkyl 
amphodipropionates, alkyl amphodiacetates, alkyl amphoglycinates and alkyl 
amphopropionates wherein alkyl represents an alkyl group having 6 to 20 
carbon atoms. Other suitable amphoteric surfactants include 
alkyliminopropionates, alkyl iminodipropionates and alkyl 
amphopropylsulfonates having between 12 and 18 carbon atoms, alkylbetaines 
and amidopropylbetaines and alkylsultaines and alkylamidopropylhydroxy 
sultaines wherein alkyl represents an alkyl group having 6 to 20 carbon 
atoms. 
Anionic surfactants which may be selected include any of the known 
hydrophobes attached to a carboxylate, sulfonate, sulfate or phosphate 
solubilizing group including salts. Salts may be the sodium, potassium, 
calcium, magnesium, barium, iron, ammonium and amine salts of such 
surfactants. 
Examples of such anionic surfactants include water soluble salts of alkyl 
benzene sulfonates having between 8 and 22 carbon atoms in the alkyl 
group, alkyl ether sulfates having between 8 and 22 carbon atoms in the 
alkyl group, alkali metal, ammonium and alkanolammonium salts or organic 
sulfuric reaction products having in their molecular structure an alkyl, 
or alkaryl group containing from 8 to 22 carbon atoms and a sulfonic or 
sulfuric acid ester group. 
Preferred are linear sodium and potassium alkyl sulfates. Particularly 
preferred is the use of sodium lauryl sulfate (sodium dodecyl sulfate). 
Another preferred type of anionic surfactant are alkyl benzene sulfonates, 
in which the alkyl group contains between about 9 to about 15, and even 
more preferably, between about 11 to about 13 carbon atoms in a straight 
chain or branched chain configuration and even most preferred a linear 
straight chain having an average alkyl group of about 11 carbon atoms. 
In some embodiments, mixtures of anionic surfactants may be utilized, with 
mixtures of alkyl or alkylaryl sulfonate and sulfate surfactants being 
especially preferred. Such embodiments comprise a mixture of alkali metal 
salts, preferably sodium salts, of alkyl benzene sulfonates having from 
about 9 to 15, and more preferred between 11 and 13 carbon atoms with an 
alkali metal salt, preferably sodium, of an alkyl sulfate or alkyl ethoxy 
sulfate having 10 to 20 and preferably 12 to 18 carbon atoms and an 
average ethoxylation of 2 to 4. 
Specific anionic surfactants which may be selected include linear alkyl 
benzene sulfonates such as dodecylbenzene sulfonate, decylbenzene 
sulfonate, undecylbenzene sulfonate, tridecylbenzene sulfonate, 
nonylbenzene sulfonate and the sodium, potassium, ammonium, 
triethanolammonium and isopropylammonium salts thereof. 
Examples of useful nonionic surfactants include condensates of ethylene 
oxide with a hydrophobic moiety which has an average hydrophilic 
lipophilic balance (HLB) between about 8 to about 16, and more preferably, 
between about 10 and about 12.5. These surfactants include the 
condensation products of primary or secondary aliphatic alcohols having 
from about 8 to about 24 carbon atoms, in either straight or branched 
chain configuration, with from about 2 to about 40, and preferably between 
about 2 and about 9 moles of ethylene oxide per mole of alcohol. 
Other suitable nonionic surfactants include the condensation products of 
about 6 to about 12 carbon atom alkyl phenols with about 3 to about 30, 
and preferably between about 5 and about 14 moles of ethylene oxide. 
Examples of such surfactants are sold under the trade names Igepol CO 530, 
Igepol CO 630, Igepol CO 720 and Igepol CO 730 by Rhone-Poulenc Inc. Still 
other suitable nonionic surfactants are described in U.S. Pat. No. 
3,976,586. To the extent necessary, this patent is expressly incorporated 
by reference. 
Examples of cationic surfactants include cetyl trimethyl ammonium bromide. 
Other surfactants which may be used include those described in McCutcheons, 
"Detergents and Emulsifiers," 1978 North American, Edition, Published by 
McCutcheon's Division, MC Publishing Corp., Glen Rock, N.J., UESTA., as 
well as the various subsequent editions. To the extent necessary, this 
reference is expressly incorporated by reference. 
In practice the amount of surfactant present in the aqueous phase ranges 
between about 0.5 to about 6.3 percent by weight of the monomers added. 
Amounts between about 0.5 and about 3.0 percent by weight of the total 
monomers added are more preferred and amounts between about 1.0 and about 
3.0 percent by weight of the total monomers added are most preferred. In 
general, the particle size of the latex decreases with increasing amounts 
of surfactant added up to about 3.0 weight percent. Beyond 3.0 weight 
percent surfactant, the decrease in particle size is far less pronounced. 
The reaction medium can include between about 0.5 to about 10.0 percent by 
weight of the monomers added of other optional additives to provide 
specific functional properties to the final latex. Examples of such 
additives include plasticizers such as polyethylene glycol, defoamers, 
pigments, colorants, dyes, and antibacterials. 
To produce the novel textile sizing latexes of the present invention a 
semi-continuous or continuous polymerization process is utilized. This 
involves adding the monomer, including cross-linking agent if necessary 
and initiator solutions incrementally to the reaction vessel, which is 
typically heated to temperatures between about 45.degree. C. and about 
90.degree. C. and includes water and one or more emulsifiers over a period 
of time as opposed to a batchwise addition. Optionally, the reaction 
vessel can contain a small amount of monomer before commencement of the 
incremental polymerization to act as a "seed". Such a small amount of 
monomer is generally below 30 percent by weight and desirably no more than 
about 10 percent by weight of the total monomer utilized. The rate of the 
monomer addition is generally governed by various factors such as reaction 
vessel size, exothermic reaction temperature increase, cooling capacity of 
the reaction vessel, and the like, such that the reaction temperature is 
generally maintained at a specific value or range. 
The amount of the one or more emulsifiers generally contained in the 
reaction vessel is generally at least 50 or 60 percent by weight, 
desirably at least 70 percent by weight, more desirably at least 80 
percent by weight, and preferably at least 90 percent by weight of the 
total amount of emulsifiers. The remaining emulsifier, if any, is fed with 
either the monomer or initiator feed streams. 
The reaction vessel may be maintained at temperatures as low as ambient 
temperatures (10.degree. C. to 20.degree.) up to the boiling point of the 
aqueous solution. The reaction pressure is generally atmospheric, but may 
be elevated if necessary to assist in polymerization. 
As discussed above, the monomer feed and the initiator feed may be the same 
feed if the initiator is monomer soluble. Further, if the initiator is 
water soluble and charged, such as ammonium persulfate, it is fed such 
that the ionicity throughout the reaction vessel is maintained at a 
constant. This is typically accomplished by initially transferring an 
amount of the water from the reaction vessel to the initiator feed to 
create ionic concentrations in both the feed vessel and the reaction 
vessel which are substantially equal. 
Feeding the initiator solution on an incremental basis provides for a 
generally steady state free radical concentration throughout the monomer 
addition. This steady state free radical concentration avoids the low 
radical concentrations seen with single charges of initiators and 
prolonged feed times. It is this continual and ready availability of free 
radicals that allows new chain and particle formation to compete 
effectively with addition of monomer to existing particles. As compared to 
so-called single shot initiator feed systems, the inventive process 
markedly improves the monodispersity of the resulting latex. 
Polymerization continues until all of the monomer(s) and initiator has been 
added into the reaction vessel and until nearly all of the monomer feed 
has been converted to a polymerized form. Polymerization is generally 
continued until a high conversion is achieved as in excess of 80 percent, 
desirably at least 90 or 95 percent, and preferably at least 98 percent or 
even complete conversion. 
Regardless of the particular type of monomers selected for polymerization 
in the process as set forth above, the polymer average particle size is 
very small. By the term "particle size" it is meant the volume average 
median particle size as measured by photocorellation spectroscopy. 
Polymeric latexes produced according to the present invention have a very 
small volume average particle size of 100 nanometers of less, with average 
preferred particle sizes of between about 1 and about 60 nanometers, more 
preferred between about 5 and about 40 nanometers, still more preferred 
between about 10 and about 30 nanometers, and ideally between about 10 and 
about 20 nanometers. Generally, any of the above particle size ranges can 
be produced depending upon the specific end properties desired. 
Further, and particularly because of the incremental initiator feed system 
used, the range of the produced particle size range is limited. In 
practice the standard deviation for each desired size latex is no more 
than 4 nanometers. 
The above process yields a polymeric latex which is coagulation stable 
inasmuch as it can be diluted with water without coagulation occurring. 
The solids content of the latex is relatively high as from about 5 percent 
to about 55 percent by weight, desirably from about 15 percent to about 50 
percent by weight, more preferably from about 20 to about 40 percent by 
weight, and most preferably from about 25 to about 35 percent by weight 
based upon the total weight of the aqueous polymeric latex. 
To utilize the inventive aqueous dispersion as textile sizing compositions, 
the compositions are simply applied to textile fibers. Examples of textile 
fibers is meant to include polyamide fibers such as Nylon 6, Nylon 66 and 
Nylon 610; polyester fibers such as Dacron, Fotrel and Kodel; acrylic 
fibers such as Acrolan, Orlon and Creslan; modacrylic fibers such as Verel 
and Dynel; polyolefinic fibers such as polyethylene and polypropylene; 
cellulose ester fibers such as Arnel and Acele; polyvinyl alcohol fibers; 
natural fibers such as cotton and wool, manmade cellulosic fibers such as 
rayon and regenerated cellulose; and the like. 
Application of the sizing compositions to the fibers is typically 
accomplished by means known in the art. For example, yarn samples are 
prepared via slashing (sizing) on a bench-top slasher in which the yarn is 
drawn through a bath containing the size at concentrations ranging from 
0-15 wt % and subsequently drawn across a series of driven, heated 
rollers. The dried yarn is then conditioned for a minimum of 24 hours 
prior to evaluation. Evaluations consist of, but are not limited to, 
comparative tests of: yarn stiffness, abrasion resistance, and filament 
bundle integrity upon yarn breakage. No matter what coating method is 
utilized to apply the composition to the textile fibers, no neutralization 
step is necessary. This provides a significant cost and environmental 
advantage as compared to prior art sizing materials. 
For use as textile sizing compositions it is particularly desired that the 
average molecular weight of the polymers of the one or more emulsions be 
controlled depending on the monomer(s) selected. If the molecular weight 
is too high, the emulsions may not be ideal sizing agents as high 
molecular weight lead to poor removal of the size from the yarn. 
Maintenance of the desired molecular weight profile may be accomplished by 
adding a chain transfer agent, such as N-dodecylmercaptan to the emulsion. 
The amount of chain transfer agent added typically ranges between about 
0.1 and about 1.5 parts per hundred parts monomer added. 
Further advantages of utilizing the inventive sizing materials include 
preferred molecular weight with low viscosity; good water resistance; no 
need for dissolution; better overall sizing due to the particles acting 
like a weld; and versatility. 
The invention will be better understood by reference to the following 
examples.

EXAMPLE 1 
To a solution containing 3.1 parts per hundred monomer (PHM) sodium lauryl 
sulfate and 245 PHM water heated to 85.degree. C. are added continuously 
and simultaneously two separate feeds. One feed is comprised of 0.32 PHM 
ammonium persulfate dissolved in 85 PHM of water and the other feed is 
comprised of 10 PHM of styrene, 25 PHM methacrylic acid, and 65 PHM butyl 
acrylate and 0.5 PHM N-dodecylmercaptan. Addition of each separate feed 
occurs for approximately 2.5 hours and each feed stream is metered into 
the reaction vessel in such a way that both feed streams are completed 
depleted after approximately 2-5 hours. A solution containing 0.1 PHM 
sodium metabisulfite dissolved in 24 PHM water is then metered into the 
reaction mixture over an interval of 1/2 hour. The temperature is 
maintained for 1 hour and the reaction mixture is subsequently cooled to 
room temperature and is filtered. A blue-clear latex is yielded having a 
solids level of 23.3% and an average particle size of about 14 nanometers. 
The T.sub.g of this latex is -5.3.degree. C. 
EXAMPLE 2 
To a mixture maintained at 85.degree. C. and containing 8 g of sodium 
lauryl sulfate and 800 g of H.sub.2 O are added 0.81 g ammonium persulfate 
dissolved in 2 g H.sub.2 O, and then, continuously, a monomer solution 
containing 149.6 g methyl methacrylate, 38.7 g methylacrylic acid, 69.6 g 
butyl acrylate and 4.0 g N-dodecylmercaptan. Following completion of the 
monomer addition a solution of 0.12 g ammonium persulfate dissolved in 31 
g H.sub.2 O is added. This is followed by the addition of 0.12 g sodium 
metabisulfite dissolved in 31 g H.sub.2 O. Following addition of this 
redox system the temperature is raised to 95.degree. C. and 1.0 g of 
H.sub.2 O.sub.2 (35%) is added to the mixture. The solution is heated for 
an additional 1 hour then cooled to room temperature. The calculated 
T.sub.g of the resulting ultrafine sized latex is +52.9.degree. C. The 
particle size of this latex is 25 nanometers. 
Samples of this emulsion are cast on mylar substrates and allowed to air 
dry. They are then evaluated at 45% and 75% relative humidity. Films are 
also heat set at 200.degree. C. for 35 seconds to determine resolubility 
temperature. 150 Denier/48 filament polyester yarn is sized with this 
composition without the prior addition of a neutralizing agent to the 
composition. For use as a comparison, commercially available products, 
which must be neutralized prior to application, are also tested. 
The inventive emulsion films give good adhesion to the mylar substrate but 
appear to be tougher and more brittle than the neutralized versions even 
at higher humidity. Heat set solubility is 175.degree. to 180.degree. F., 
about 10.degree. F. higher then the neutralized version. This is not 
unusual with an unneutralized product. The inventive polymer is used at 
10% concentration to size the polyester yarn. The polymer gives good 
adhesion to the yarn. The water resistance of the inventive polymer may be 
particularly advantageous for use on waterjet looms. 
EXAMPLE 3 
To a solution containing 3.1 PHM sodium lauryl sulfate, 0.3 PHM TDET 9.5 (a 
nonionic surfactant) and 283 PHM water heated to 85.degree. C. is added 
0.83 g ammonium persulfate dissolved in 2 g water. To this mixture is 
continuously added over an interval of about 2.5 hours a feed comprised of 
90 PHM butyl acrylate, 10 PHM acrylic acid and 1 PHM N-dodecyl mercaptan. 
A solution containing 0.046 PHM ammonium persulfate and 9.3 PHM water is 
then metered into the reaction mixture over an interval of five minutes. 
To the resulting mixture is added a solution containing 0.046 PHM sodium 
metabisulfate and 9.3 PHM water over a five minute interval. The mixture 
is then heated to 95.degree. C. and a solution containing 1.16 PHM H.sub.2 
O.sub.2 (35 wt %) is added. The temperature is maintained for 1 hour and 
the reaction mixture is subsequently cooled to room temperature and is 
filtered. A blue-clear latex is yielded having a solids level of 25.2 wt % 
and a particle size of 35 nanometers. Its T.sub.g is -44.degree. C. 
EXAMPLE 4 
Between about 10 and about 70 parts of the latexes of either Examples 1 or 
2 are mixed with between about 90 and about 30 parts of the latex of 
Example 3. These blend compositions are applied to filament yarns using 
known conditions for functioning as a textile size. The polymer of Example 
3 functions to glue together the filament yarns while at the same time the 
polymers of Examples 1 or 2 function as migratory additives that can 
eliminate surface tackiness and blocking associated with the polymer of 
Example 3. During the sizing operation, the polymer of Example 3 forms 
"spot-welds" between the yarn fibers whereas the polymer of Examples 1 or 
2 apparently migrates to the outer surfaces of the "spot-welds", yielding 
a hard, non-tacky shell. 
The inventive blend compositions are compared with the commercial products 
Permaloid 150 and Permaloid 172, both manufactured by Rhone-Poulenc Inc. 
for use as textile sizes. All samples are evaluated at concentrations of 
7% and applied to polyester filament yarn via a lab scale slasher. The 
abrasion resistance of the latex blends is approximately equal to that of 
Permaloid 150 and Permaloid 172. The advantage rendered by use of the 
inventive latex blends is the absence of neutralization prior to 
application. Conventional sizes, such as Permaloid 150 and Permaloid 172 
are applied as solution polymers prepared by the alkali induced 
solubilization of a conventional latex polymer. The inventive ultrafine 
latex based textile sizes are applied directly to the yarn without 
neutralization. This eliminates the need for alkali or the monitoring of 
ammonia release normally associated with the sizing of filament yarns and 
hence provides significant advantages as compared to commercially 
available materials. 
Having described the invention in detail and by reference to the preferred 
embodiments thereof, it will be apparent that modifications and variations 
are possible without departing from the scope of the appended claims.