Disclosed is a water-insoluble addition copolymer of an ethylenically unsaturated unsubstituted amide and at least one other ethylenically unsaturated monomer comprising sufficient amide groups mono-functionally bonded to a polyaldehyde to render the copolymer thermosettable. The copolymer is adapted for use as or for formulation in a binder. Such a binder is readily made from a copolymer latex and is useful in processes for the preparation of products such as nonwoven fabrics and bonded papers.

BACKGROUND OF THE INVENTION 
The present invention is concerned with water-insoluble addition copolymers 
of ethylenically unsaturated amides and other ethylenically unsaturated 
monomers in which sufficient amide groups are mono-functionally bonded to 
a polyaldehyde to render the copolymer thermosettable. The copolymer is 
readily made in the form of a copolymer latex and is useful in processes 
for the treatment of textile substrates such as binders for nonwoven 
fabrics and hand or softness modifiers, and in the preparation of papers 
utilizing binders or coatings. 
It is known in the art to employ water-insoluble aldehyde-substituted amide 
copolymers, in which the aldehyde is a mono-aldehyde, such as 
formaldehyde, as a binder. Christenson, U.S. Pat. No. 3,037,963, teaches 
the preparation of mono-aldehyde-substituted amide copolymers, 
particularly those in which the amide copolymer is a copolymer of 
acrylamide and the aldehyde is formaldehyde. Kine, et al., in U.S. Pat. 
No. 3,157,562, teach that certain linear addition copolymers containing 
N-methylolamide groups and amide groups, in certain proportions, serve as 
binders for nonwoven fabrics. Steiger et al., in U.S. Pat. No. 3,100,674, 
teach the use of N-methylolamide copolymers for the stabilization against 
shrinkage of protein-containing woven and knitted textile materials. In 
discussing the usable aldehydes, Christenson (U.S. Pat. No. 3,037,963 
column 7, line 6) comments "Aldehydes containing two or more aldehyde 
groups, such as glyoxal, are unsatisfactory and should not be used 
inasmuch as they cause gel formation when reacted with amide 
interpolymers." Talet, U.S. Pat. No. 2,886,557, reacts glyoxal with an 
acrylamide copolymer to produce a crosslinked polymer. We have discovered 
how to prepare water-insoluble amide copolymers coreacted with 
polyaldehydes without forming a crosslinked polymer gel. Thus this polymer 
is useable as a thermosettable binder or treating agent in textile and 
paper technology. The thermosettable polymer is useful as a 
self-crosslinking system or, if desired, with external crosslinkers. 
Self-crosslinking polymer systems are particularly useful as adhesives in 
soft fiber fabrics, as the bonding agent to bond a laminate foam to a 
fabric or a fabric to another fabric, as the bonding agent in nonwoven 
fabrics, as a fabric backing agent, as a pigment binder especially for use 
on paper and to bind pigments to glass fabrics, as a pigment binder 
particularly in pigment printing and dyeing of fabrics, as a fabric 
finishing agent to modify the hand or weight of a fabric, as a finish for 
breatheable waterproof colored fabric, as a stabilizer for woolen and 
worsted fabrics and as a binder for papers. The self-crosslinking nature 
of the systems produces, upon appropriate curing, products with excellent 
durability to washing and dry cleaning. The addition of external 
crosslinking agents is not necessary to produce the appropriate 
crosslinking although in certain instances it is found useful. 
Exposure of workers to formaldehyde has been of growing concern to industry 
and to regulatory agencies responsible for worker safety. The various 
formaldehyde amide adducts, such as polymers containing 
methylolacrylamide, urea formaldehyde resins or crosslinkers and melamine 
formaldehyde resins or crosslinkers, produce free formaldehyde during 
curing operations and during storage periods, both before and after 
curing. One of the purposes of this invention is to replace these binder 
systems, which produce the toxic formaldehyde particularly during 
manufacture, by a binder system which is handleable in manufacturing 
facilities without the necessity for extreme safety precautions. Fabrics 
utilizing formaldehyde-containing polymers are often found to be 
irritants, especially when used in contact with sensitive tissues, so a 
replacement polymer, such as that of the instant invention, is needed. 
BRIEF SUMMARY OF THE INVENTION 
This invention relates to a polymer composition comprising a 
water-insoluble addition copolymer of (A) a monomer which is the product 
of an ethylenically unsaturated unsubstituted amide monomer condensed with 
one aldehyde group of a polyaldehyde, the product having at least one free 
aldehyde group, and (B) at least one other ethylenically unsaturated 
monomer; the amide monomer component of (A) and any unsubstituted amide 
monomer of (B) being up to 25% of the total monomers, by weight. In a 
preferred embodiment, the copolymer has sufficient unsubstituted amide 
groups among the (B) monomers and amide groups mono-functionally bonded to 
a polyaldehyde, (A), to be thermosettable. In another embodiment, an 
external crosslinker is used in the binder composition. The invention also 
relates to processes for producing the polymer and for using the polymer 
in the manufacture of fabrics and papers. A preferred state in which the 
polymer is manufactured and used is as a stable polymer latex or polymer 
emulsion. 
The most important of the other ethylenically unsaturated monomers, other 
than the amides, are: (1) vinyl esters of an aliphatic acid having 1 to 18 
carbon atoms, especially vinyl acetate; (2) acrylic acid esters and 
methacrylic acid esters of an alcohol having 1 to 18 carbon atoms, and (3) 
ethylenically unsaturated hydrocabons such as ethylene, propylene, 
isobutylene, styrene, alphamethyl styrene and aliphatic dienes such as 
butadiene, isoprene and chloroprene. 
The ethylenically unsaturated amide of utility in copolymer components (A) 
and (B) is a polymerizable amide such as acrylamide, methacrylamide and 
itaconic half ester amide and diamide. Glyoxal is an example of the 
polyaldehyde which is mono-functionally bonded to an amide group to give 
the following structure: 
##STR1## 
wherein R.sub.1, R.sub.2 and R.sub.3 are independently, hydrogen, a 
monofunctional organic group or two of them together are a difunctional 
organic group and A is a single bond, as in glyoxal, or a di-functional 
organic group. Thus the polymer is a polyaldehyde-modified, 
amide-containing, addition copolymer which is used in the manufacture or 
processing of fabrics or papers. The fabrics produced have sufficient 
resistance to washing and dry cleaning for most practical purposes even 
without the employment of an external crosslinker, such as an aminoplast 
or a polyepoxide in conjunction with the polyaldehyde-modified, 
amide-containing polymer. The amide-containing polymers, when cured as by 
heating at an elevated temperature, impart resistance to normal laundering 
operations, such as may be performed with modern detergents, as well as 
resistance to dry cleaning, which may be performed by chlorinated 
hydrocarbons. 
The copolymers of the present invention are water-insoluble linear addition 
copolymers preferably prepared by emulsion copolymerization. The 
copolymers are prepared using up to 25 percent of amide monomers and the 
remainder other ethylenically unsaturated monomers. Amide groups of the 
polymer are predominantly condensed with one aldehyde group of a 
polyaldehyde, as indicated by the absence of gelation, and there remain 
free aldehyde groups on the polyaldehyde, as shown by the curability of 
the polymer. Thus the polymer comprises unreacted aldehyde groups and in 
the selfcuring embodiment, unreacted amide groups. In a preferred 
embodiment, the polymer also comprises acid groups. 
The preferred polymers of this invention are those in which the 
polyaldehyde is glyoxal. A preferred method for preparing the polymers is 
by emulsion polymerization of the monomers in the presence of the 
polyaldehyde, under conditions such that the reaction of the polyaldehyde 
and the amide occurs, in a one step process producing a polymer which is 
still thermosettable. The thermosettable nature of the product indicates 
that there are unreacted aldehyde groups available for crosslinking to 
other groups reactable with the aldehyde such as other amide groups. The 
latex so produced is used in the manufacture of paper or fabric products 
following the art-known procedures used for monoaldehyde-amide containing 
copolymers. Of course, those skilled in the art will make the necessary 
accommodations for modest differences in reaction rates between the 
monoaldehydes formerly employed and the polyaldehyde-amide of the present 
invention. The fabric or paper containing the polymer is cured at an 
elevated temperature for a suitable length of time. The cured material is 
water resistant and solvent resistant. It is hypothecized that the 
improvement in both strength and resistance properties obtained on curing 
is due to further coreaction of the aldehyde and amide groups which had 
been pendant on the polymer to produce a crosslinked polymer. 
DETAILED DESCRIPTION 
The polymer composition of this invention is preferably prepared in latex 
form as a water-insoluble addition copolymer of an ethylenically 
unsaturated amide and at least one other ethylenically unsaturated 
monomer. Preferably, the polymerization is carried out in the presence of 
a polyaldehyde which bonds to the polymer via the amide groups on the 
polymer so as to render the copolymer thermosettable. The copolymer is 
little, if any, crosslinked by the polyaldehyde during the polymerization. 
It is believed that the polyaldehyde is preponderantly mono-functionally 
bonded to the copolymer. Thus the copolymer is not crosslinked but is 
still crosslinkable at the end of the polymerization step. Although there 
are unreacted aldehyde groups in the polymer, the latex is stable and does 
not gel when stored at room temperature for months or even longer. The 
produced latex, in a formulation if desired, is applied to the appropriate 
substrate and the polymer is crosslinked, by curing via heating, using 
art-known steps for the given use. 
It is preferred that the polyaldehyde be at least slightly water soluble 
such as gluteraldehyde or 2-imidazolidone-1,3-bis(2,2-dimethylpropanol) or 
more preferably, water soluble such as glyoxal. By polyaldehyde, what is 
meant in this specification is a non-polymeric organic molecule with more 
than one 
##STR2## 
group. Aldehydes often form homopolymers or copolymers with water that are 
not the polyaldehydes referred to in this specification. The preferred 
polyaldehyde of this invention is glyoxal, ordinarily depicted by the 
structure 
##STR3## 
Glyoxal is most commonly available commercially as a 40% aqueous solution. 
In this form glyoxal has no appreciable vapor pressure and is not, under 
atmospheric or vacuum stripping conditions, distillable from water. 
Aqueous solutions of glyoxal are nonexplosive and nonflammable. Glyoxal in 
its hydrated form (II) is believed to exist in equilibrium with (IIa) and 
(IIb): 
##STR4## 
In the discussion of molar ratios with respect to amides, the simplified 
OHC--CHO depiction is used in this specification. 
The ethylenically unsaturated unsubstituted amide monomers of this 
invention include acrylamide, methacrylamide, itaconic diamide, 
crotonamide, acryloxypropionamide, maleic, fumaric and itaconic half 
amides and so forth. The preferred amides are methacrylamide and 
especially acrylamide. An unsubstituted amide is an amide having two 
hydrogens on the amide nitrogen, i.e., the amide group --CONH.sub.2. 
Among the other ethylenically unsaturated monomers useful in this invention 
are the vinyl esters of an aliphatic acid having 1 to 8 carbon atoms such 
as vinyl formate, vinyl acetate, vinyl propionate, vinyl butyrate, and 
vinyl versitate. Preferred is vinyl acetate particularly when used with 
one or more of the following: vinyl chloride, vinylidene chloride, 
styrene, vinyl toluene, acrylonitrile, methacrylonitrile, and acrylate or 
methacrylate esters. The acrylate and methacrylate esters of alkyl and 
cycloalkyl alcohols having 1 to 18 carbon atoms form useful polymers, with 
C.sub.1 to C.sub.8 alcohols being preferred, particularly mixtures of 
these and also in mixtures with the following monomers: vinyl acetate, 
vinyl chloride, vinylidene chloride, styrene, .alpha.-methyl styrene, 
vinyl toluene, acrylonitrile and methacrylonitrile. The unsaturated 
hydrocarbons, such as ethylene, isobutylene and styrene are particularly 
useful when used in conjunction with one or more esters, nitriles or 
amides of acrylic acid or of methacrylic acid or with vinyl esters, vinyl 
chloride or vinylidene chloride. In all of these systems, it is quite 
common and indeed useful to include a small amount such as a 1/2 percent 
to about 21/2 percent, 4%, or perhaps 8% or more, of an ethylenically 
unsaturated carboxylic acid monomer in the monomer mixture used for making 
the copolymers. Acids used include acrylic, methacrylic, itaconic, 
aconitic, citraconic, crotonic, maleic, fumaric the dimer of methacrylic 
acid and so forth. The use of the acids often aids in the curing of the 
polymer. Esters of these acids with C.sub.1 to C.sub.18 alcohols may be 
used. The preferred esters of methacrylic acid in these copolymers are 
methyl, ethyl, propyl and butyl with methyl being most preferred. The 
preferred esters of acrylic acid are the methyl, ethyl, n-propyl, 
isopropyl, n-butyl, secondary butyl, isobutyl and 2-ethylhexyl esters. A 
copolymer composition containing at least about 60% by weight of esters of 
acrylic or methacrylic acid or a mixture of these is especially useful. 
The preferred copolymers of the present invention are water-insoluble, 
linear addition copolymers obtained by emulsion copolymerization of 
unsubstituted amide monomers with other monomers; the copolymerization 
being carried out in the presence of a polyaldehyde. The upper limit of 
the concentration of amide monomer is determined by the solubility of the 
copolymer formed; there is to be less amide monomer than the amount 
sufficient to render the copolymer water soluble. Although 25% may be 
employed, it is found that 12% by weight of amide monomer, on copolymer, 
normally suffices and 0.5% is a usual lower limit for effective 
crosslinking. Preferably, the amide monomer content is between 2% and 10% 
with 3% to 6% being most preferred. These amide monomer composition limits 
are calculated on the basis of the amide monomer ingredients before 
condensation with a polyaldehyde. 
In a self-crosslinking embodiment of this invention the amount of 
polyaldehyde used is such that there is sufficient to give effective 
crosslinking but not so much in relation to the amount of amide present 
that substantially all of the amide groups are reacted with polyaldehyde 
during the polymerization. These desiderata are achieved when there are 
about 0.2 to about 0.8 of a mole of polyaldehyde per mole of amide groups. 
Thus, when the latex is prepared and applied to the fabric or paper for 
the curing or second stage reaction if there is 0.2 mole of polyaldehyde 
per mole of amide there is 0.8 mole of amide groups available for the 
crosslinking reaction. At the other extreme, when 0.8 mole of polyaldehyde 
per mole of amide groups is incorporated during the polymerization, then 
0.2 mole of amide groups are available for the crosslinking reaction 
during curing. Preferably, there is between 0.4 and 0.6 mole of 
polyaldehyde per mole of amide groups with 0.45 to 0.55 mole of 
polyaldehyde per mole of amide groups being most preferred. 
In another embodiment of this invention, 0.5, preferably 0.7 to one mole of 
polyaldehyde per amide group is present during the polymerization. In this 
embodiment, crosslinking is achieved by use of an external aminoplast 
crosslinking agent such as a polyamide or a compound containing amide-like 
NH.sub.2 groups, such as urea and melamine, or aldehyde-substituted amide 
groups including dihydroxy ethylene urea. This includes the aldehyde and 
alcohol/aldehyde adducts of urea and melamine. Use of the formaldehyde 
adducts would defeat the purpose of the invention so formaldehyde-free 
aminoplasts are preferred. Among the preferred polyamides which can be 
employed are those of oxalic, malonic, adipic, pinelic, suberic, azelaic, 
sebacic, isophthalic, terephthalic and the like acids. Also, there may be 
employed the amides of dimer and trimer acids and mixtures thereof; these 
acids are prepared by the polymerization of C.sub.18 fatty acids. The 
external crosslinking agent is used in an amount up to about 25% of the 
copolymer, up to 11% being preferred, and up to 7% being most preferred. 
Formulations in which the polyaldehyde to amide ratio is high usefully 
embody 0.5% or more, preferably over 2% of external crosslinker. 
The glass transition temperature of the copolymer, before curing, is below 
35.degree. C., preferably below 20.degree. C. and most preferably below 
0.degree. C. The weight average molecular weight of the polymer, aside 
from any small amounts which may be gelled, is preferably between 100,000 
and 10,000,000 with 300,000 to 3,000,000 being preferred. 
A polyaldehyde, such as glyoxal, admixed but not coreacted with an amide 
copolymer, such as a copolymer of acrylamide or methacrylamide, may be 
applied to a substrate and cured to produce a fabric or paper. The fabric 
or paper so produced is found to be less resistant to water, laundering 
and dry cleaning than fabric or paper employing the copolymers of this 
invention, other conditions being the same. In general, high proportions 
of the crosslinking moieties taken together, that is, of amide and 
aldehyde, tend to give products which are excessively stiff. Of course, in 
certain applications, the stiffness is desirable. Low levels of amide or 
aldehyde lead to a loss of the resistance properties. 
An especially useful polymer is a copolymer of, by weight, 20 to 96 ethyl 
acrylate, 0 to 96 propyl or butyl acrylate or a mixture thereof, 0 to 25% 
acrylonitrile, 0 to 50% methyl methacrylate, 3 to 6% acrylamide, 0 to 2% 
itaconic acid and 1 to 2% glyoxal. More preferred is a copolymer which 
consists consists of 70 to 92.5% ethyl acrylate, 3 to 5% acrylonitrile, 0 
to 25% butyl acrylate, 0 to 10% methyl methacrylate, 3 to 4% acrylamide, 
and 0.5 to 1.5% itaconic acid and 1 to 2% glyoxal, by weight. 
The preferred copolymerization process is a conventional emulsion 
polymerization procedure with certain modifications. "Emulsion 
Polymerization" is taught in books, so titled, by D. C. Blackley (Wiley, 
1975) and by F. A. Bovey et al. (Interscience Publishers, 1965). The 
coreaction of the aldehydes (mono-functionally) with the amide during the 
polymerization is favored by using a thermal polymerization process, the 
presence of all of the aldehyde in the kettle charge at the beginning of 
the polymerization or prior to the polymerization and the presence of part 
of the amide in the kettle prior to the polymerization. It is preferred 
that at least one third and more preferable that at least two thirds of 
the total aldehyde and that up to 25%, preferably 17% and more preferably 
10%, of the total amide monomer be in the kettle charge. The 
aldehyde-amide reaction need not be completed before the polymerization is 
begun thus the polymerization is carried out in the presence of any 
remaining polyaldehyde and of a free radical initiator. At the end of the 
polymerization substantially all of the glyoxal in the latex is bonded to 
the copolymer. The emulsion polymerization procedures may employ a 
suitable emulsifier, preferably an anionic emulsifier and a free radical 
initiator which may, if desired, although it is not the preferable system, 
be a component of any of the well known redox initiator systems. Preferred 
emulsifiers are sulfates and sulfonates such as sodium lauryl sulfate, and 
sodium dodecyl benzene sulfonate. Many others are well known in the 
emulsion polymerization art. The amount of emulsifier is usually between 
1/2% and 6% on the weight of monomers with 1% to 3% being preferred. From 
0.1% to about 2% on the weight of monomers of free radical iniator such as 
azodiisobutyronitrile, t-butylhydroxyperoxide, ammonium, sodium or 
potassium persulfate may be employed. Suitable chaser systems are employed 
to result in a polymer system essentially free of formaldehyde, amide 
monomer and polyaldehyde. The polymerization process may be one which 
produces graft or block copolymers wherein one or more but not all of the 
monomers are first polymerized and then one or more other monomers are 
copolymerized with the first polymer obtained. 
The latex is usually at an acid pH as manufactured, typical values being in 
the pH range from two to three. Formulation of the latex for a given 
application may shift the pH, for example incorporation of an acid 
catalyst usually lowers the pH somewhat, a drop of about a half unit is 
often found. In preferred formulations the system is stable at room 
temperature including formulations containing acid catalysts. 
A preferred use of the binders of the present invention is to bind nonwoven 
webs to form nonwoven fabrics. The selection of fibers and the description 
of the application of a binder is given in U.S. Pat. No. 3,157,562, column 
3, line 30 to column 4, line 53, herein incorporated by reference. 
Although it is not intended to limit the invention by any theory or 
theoretical structure herein presented, certain concepts are presented as 
aids in teaching the invention. It is believed that during the formation 
of the polymer, the polyaldehyde reacts with amide groups on the monomer 
or on the polymer by means of one amide group reacting with one aldehyde 
group. This reaction occurs before, and/or contemporaneous with, the vinyl 
polymerization reaction which forms the polymer. In some instances the 
aldehyde-amide reaction occurs, in the polymerization vessel, subsequent 
to the polymerization. Using as typical an acrylamide unit in the polymer 
and glyoxal as the aldehyde, the resulting unit in the aldehyde polymer 
adduct has the theoretical formula (III). 
##STR5## 
During curing in a self-crosslinking embodiment of this invention, the 
reaction depicted to form crosslinked structure (IV) occurs. In a typical 
embodiment employing an external crosslinker, in this instance urea, the 
following reaction is thought to occur, producing crosslinking by means of 
structure (V): 
##STR6## 
In the self-crosslinking reaction, a dependent aldehyde group of one 
polymer molecule reacts with an amide group of another polymer molecule to 
give the crosslinked structure believed to be depicted by structure (IV). 
In the case of the external crosslinker, again two polymer molecules are 
joined this time via an external crosslinker molecule, such as urea, with 
the crosslinked structure being depicted as in structure (V). The aldehyde 
may react with other types of groups containing reactive hydrogen, the 
groups being those of others of the polymer molecules or of other 
crosslinking molecules. There may also be some reaction, during curing, 
between the aldehyde groups of the polymer molecules and reactive groups 
in the fibers of the paper or fabric, such as the hydroxyl groups of the 
cellulose fibers. While the precise nature of the reaction and the 
products thereby obtained are not clearly understood, it is believed that 
the resistance to laundering and dry cleaning is the result of a reaction 
between binder polymer molecules to crosslink these molecules and/or a 
reaction between the binder polymer molecules and the reactive sites of 
the fiber molecules. 
The polymers of this invention are crosslinked by a curing step which may 
either be simultaneous with or following the drying of the polymer on the 
substrate. The curing may be by long subjection to the normal atmosphere 
in high temperature climates or by heating the articles coated or 
impregnated with the polymer described herein to a temperature of 
80.degree. C. to about 400.degree. C. or higher for periods of time from a 
few seconds at the higher temperatures up to an hour or more at the lower 
temperatures. Temperatures below 80.degree. C. may be employed if somewhat 
longer times are used. Typical schedules for air dried systems are about 
15 seconds to about 15 minutes at temperatures in the neighborhood of 
150.degree. C. The polymer of this invention may be used in combination 
with other polymers commonly employed in bonding or treating fabrics and 
paper. 
Although catalysts are not necessary to obtain the crosslinking desired in 
the cure step, they may be used. Acid catalysts, well known in the art, 
may be employed at levels up to 1% with 0.1% to 0.5% being preferred. 
Higher levels of catalysts often, but not always, produce undesirable side 
effects. Examples of acid catalysts are oxalic acid, boron trifluoride 
ethyl etherate, salts of hydrochloric acid such as the zinc or magnesium 
salts, salts of nitric acid such as the zinc or magnesium salts, maleic 
acid, p-toluene sulfonic acid, butyl acid phosphate and so forth. 
The compositions of the present invention may be formulated with pigments, 
dyes, thickening agents and other conventional components needed to 
achieve the properties desired for the given end use. For instance, 
aqueous dispersions of these polymers may contain water-soluble thickening 
agents such as tragacanth, water-soluble cellulose ethers, polyvinyl 
alcohol or partially saponified polyvinyl acetate or polymers or 
copolymers of acrylic or methacrylic acid soluble in water. The 
proportions of the ingredients in the aqueous systems may be varied widely 
and are adjusted in any convenient manner so that the dispersion or paste 
have a consistency suitable for the application by the particular 
technique to be used for this purpose. 
The drying referred to above may be air drying by simple exposure to the 
ambient atmosphere or it may be force drying of the coated or impregnated 
material at temperatures below 80.degree. C. As noted, the air drying or 
force drying may itself produce a cured product without the need of a 
subsequent curing step. Of course, usually a cure step is desired. The 
upper limit of temperature and its duration in the curing step should be 
so selected and correlated as to avoid decomposition or other damage to 
the coated or impregnated article. The curing operation serves to render 
the polymer insoluble in organic liquids as well as water. 
The compositions may be applied to the substrates in any suitable manner 
such as by spraying, brushing, rollercoating dipping, knife-coating, and 
so on. Excess of the applied material may be wiped by any suitable 
squeegeeing operation such as between pressure rollers, by air 
squeegeeing, or by a knife or doctor blade. Thereafter, the coating may be 
dried and cured as stated hereinabove. Besides simple air-drying, there 
may be employed for this purpose heated air as in an oven or tunnel drier, 
radiation such as by infrared lamps, or electrical induction, either of 
electromagnetic or electrostatic high frequency induction fields. The 
baking or curing operation may be accomplished by the use of any suitable 
heating devices such as infrared lamps or electromagnetic or electrostatic 
high frequency induction devices. 
When the coating compositions are applied to substrates having reactive 
groups, such as paper or textiles formed of cellulosic or proteinaceous 
fibers, it is believed that the substrate may take part in the reaction 
during curing and baking so that the copolymer and the substrate are 
combined chemically, whereby outstanding adhesion, durability, and 
resistance to water, washing, laundering, and solvents, including those 
used for dry-cleaning, such as perchloroethylene, carbon tetrachloride, 
and solvent naphthas, are obtained. 
The present invention provides novel thermoplastic, thermosettable, and/or 
thermosetting copolymers which combine the qualities of efficiency, 
economy and being comparatively inert in ecological effects. Even when 
present at comparatively low levels in the copolymer, the amide-glyoxal 
system provides highly efficient cures such as cures familiar to those 
skilled in the art, obtainable by means of formaldehyde or formaldehyde 
condensate systems. The products produced have laundering resistance and 
dry cleaning resistance typical of the formaldehyde-containing systems as 
can be determined by testing the bonded or treated fabric or paper for 
durability in the presence of water or in laundering and in dry cleaning 
tests. The aqueous latexes of the present invention are sufficiently 
stable to pose no problems to the formulator or manufacturer using and 
applying these systems. 
The bonded fibrous products of the present invention are characterized by 
softness, flexibility, resistance to discoloration on exposure to 
ultraviolet light, resistance to chlorinated hydrocarbon dry-cleaning 
fluids, and resistance to laundering. Because of the softness and 
flexibility and good draping qualities of the products of the present 
invention, they are partiuclarly well adapted for use in garments where 
porosity, permeability to moisture vapor, and soft hand and feel, make the 
products advantageous where contact with the skin of a wearer may be 
involved. In general, the products are quite stable dimensionally and have 
good resilience and shape-retention properties. They are adapted for use 
not only in garments but as padding or cushioning, and moisture-absorbing 
articles, such as bibs and diapers. They are also useful as heat- and 
sound-insulating materials and as filtration media, both for liquids and 
gases. They can be laminated with paper, textile fabrics, or leather to 
modify one or both surfaces of the latter materials. They may be adhered 
to films of cellophane, polyethylene, saran, polyethyhlene glycol 
terephthalate (Mylar) or metallic foils, such as of aluminum, to improve 
the tear strength of such films and foils, to make the latter more 
amenable to stitching, and to modify other characteristics including 
strength, toughness, stiffness, appearance, and handle. 
Of particular advantage in the products of this invention is the absence of 
traces of formaldehyde. This means that wearers of the fabrics produced or 
workers who must come in close contct with the fabrics or other materials 
employing these polymers do not experience irritation due to dermal 
contact or inhalation of formaldehyde as occured with 
formaldehyde-containing materials of the prior art. Of particular 
importance is the elimination of formaldehyde, a known irritant to 
sensitive skin, from articles such as bibs and diapers. This is in 
addition to the enhanced working conditions, with respect to the 
formaldehyde-containing polymers of the prior art, due to the absence of 
formaldehyde in the plants and workrooms of the fabricators. 
While the binder may be preferentially applied, if desired, to portions of 
the fibrous product, such as one or both of the faces or parts thereof, it 
is characteristic of the binder of the present invention that, if such 
preferential treatment is not desired, substantially uniform distribution 
may be obtained because of the reduced tendency of the binder after 
initial distribution throughout the body of the fibrous product to migrate 
to the surfaces thereof during drying. 
In the examples and elsewhere herein, parts and percentages are by weight 
and temperatures in .degree.C. unless otherwise indicated. The following 
examples are illustrations designed to assist those skilled in the art to 
practice the present invention but are not intended to limit the invention 
in any way. The monomers and other chemicals used in the examples are 
commercial grade materials. Changes and variations may be made without 
departing from the spirit and scope of the invention as defined by the 
appended claims.

EXAMPLE 1. ETHYL ACRYLATE BASED LATEX 
In a kettle equipped with condenser, stirrer, thermometer and facilities 
for monomer emulsion feed, heating, cooling and nitrogen sparging, 850 g. 
of water is heated to ca. 83.degree. C. under nitrogen sparge. To this are 
added 70 g. of a 40% glyoxal (GL) solution, 4 g. of ammonium persulfate 
and 100 g. of a monomer emulsion of composition: 
800 g. water 
87 g. 23% aqueous sodium dodecyl benzene sulfonate 
80 g. acrylamide (AM) 
20 g. itaconic acid (IA) 
1872 g. ethyl acrylate (EA) 
maintaining the nitrogen sparge and with suitable agitation. After 10 
minutes, the remaining monomer emulsion is added uniformly over a 2-hour 
period along with an initiator cofeed of composition: 
4 g. sodium persulfate 
120 g. water 
During this period, the temperature is maintained at ca. 83.degree. C. 
Fifteen minutes after the addition, the batch is cooled to 55.degree. C. 
and chased with: 
______________________________________ 
1 g. 1% FeSO.sub.4 . 7H.sub.2 O in water 
premixed: 2 g. t-butyl hydroperoxide 
0.1 g. 23% sodium dodecylbenzene 
sulfonate in water 
10 g. water 
premixed: 1.2 g. sodium metabisulfite, Na.sub.2 S.sub.2 O.sub.5 
2.4 g. glyoxal 
18 g. water 
______________________________________ 
The same chaser charge is added after thirty minutes and again after sixty 
minutes. Fifteen or more minutes after the last chaser 50 g. of 35% 
aqueous hydrogen peroxide is added. The resulting copolymer has the 
composition EA/AM/IA/GL=93.5/4/1/1.5. 
EXAMPLE 2. LATEX BASED ON ETHYL-BUTYL ACRYLATES AND ACRYLONITRILE 
The polymerization procedure is the same as Example 1 except that the 
composition of the monomer emulsion is: 
800 g. water 
87 g. 23% aqueous dodecyl benzene sulfonate 
70 g. acrylamide 
30 g. itaconic acid 
90 g. acrylonitrile (AN) 
502 g. n-butyl acrylate (BA) 
1280 g. ethyl acrylate 
The resulting polymer has the composition 
EA/BA/AN/AM/IA/GL=64/25/4.5/3.5/1.5/1.5. 
EXAMPLE 3. ACID-FREE ETHYL ACRYLATE BASED LATEX 
The polymerization procedure is the same as Example 1 except that 80 g. of 
a 40% glyoxal solution is in the kettle and the composition of the monomer 
emulsion is: 
800 g. water 
87 g. 23% aqueous dodecyl benzene sulfonate 
80 g. acrylamide 
1880 g. ethyl acrylate 
The resulting polymer has the composition EA/AM/GL=94.5/4/1.5. 
EXAMPLE 4. NONWOVEN FABRIC 
The polymers of Examples 1, 2 and 3 and that of a typical acrylate latex 
based on methylolated acrylamide crosslinking are padded onto a light 
weight (0.5 oz./hd..sup.2) rayon nonwoven web to give a fiber/binder ratio 
of 80/20. The methylolated acrylamide polymer is catalyzed with 0.5% 
ammonium nitrate in the bath but the glyoxal polymers are uncatalyzed. The 
webs are air dried and then cured for two minutes at 150.degree. C. 
Tensile values are measured on 1 in..times.4 in. strips in the 
cross-machine direction (XMD) using an Instron Tester at an extension rate 
of 12 in./minute with a jaw separation of 2 in. Wet samples (water, 
perchloroethylene (PCE) and isopropanol (IPA)) are soaked for a minimum of 
30 minutes. The values reported represent maximum force before break. 
Samples measuring 12 by 12 in. are washed in an automatic washer at 
135.degree..+-.5.degree. F. with 1/4 cup of Tide.TM. detergent and 8 
terry-cloth towels as ballast. Failure to survive is measured by the 
tearing of a sample into two or more pieces. Typical results are: 
______________________________________ 
XMD Tensile Strength 
(oz./in.) 
Washes Water PCE IPA 
Binder Survived Dry Wet Wet Wet 
______________________________________ 
See Note 1 
14 25 11 14 14 
Example 1 10 24 10 13 11 
Example 2 14 32 13 17 13 
Example 3 8 22 11 13 13 
______________________________________ 
Note 1: 
The typical latex employing the formaldehyde chemistry is polymerized by 
redox procedure. It is prepared at 45% polymer in water and from the 
following monomers: 1.7% acrylamide, 2.4% Nmethylolacrylamide and 95.9% 
ethyl acrylate. 
EXAMPLES 5, 6 and 7. REDOX VS. THERMAL POLYMERIZATION AND HIGH GLYOXAL 
LEVEL 
The physical properties of a nonwoven rayon bonded with the various latexes 
is given in the following table. In the preparation of the redox latex 
(Example 5), a process similar to that of Example 1 is used except that 
the initiator consists of ammonium persulfate and sodium bisulfite with a 
trace of a ferrous salt and the temperature is about 65.degree. C. The 
latices of Examples 6 and 7 are prepared by the process of Example 1. 
TABLE I 
__________________________________________________________________________ 
XMD Tensile 
Strength (oz./in.) 
Washes Wet 
Sample.sup.a 
Composition 
AM/GL.sup.b 
Process 
Survived 
Dry 
Water 
PCE 
IPA 
__________________________________________________________________________ 
Example 5 
96EA/2.8AM/1.2GL 
2 Redox 
6 21 9.6 8.0 
6.4 
Example 6 
96EA/2.8AM/1.2GL 
2 Thermal 
6 26 9.6 9.6 
9.6 
Example 7 
94EA/3.3AM/2.7GL 
2 Thermal 
6 26 9.6 13 13 
__________________________________________________________________________ 
.sup.a Applied at 15% polymer bath solids with 0.5% NH.sub.4 NO.sub.3 
catalyst. Webs were airdried and cured at 300.degree. F./2 min. 
.sup.b Molar ratio indicated. 
These data show that the polymer polymerized by the thermal process gives a 
higher dry tensile strength and higher tensile strength in solvents than 
that polymerized by the redox process. It is also seen that the only 
advantage of the higher glyoxal to acrylamide ratio, at the higher 
acrylamide level, is in greater tensile strength in the solvent systems. 
EXAMPLES 8-11. EFFECT OF ACRYLAMIDE TO GLYOXAL RATIO 
Polymers made by the thermal process as in Example 1, in which the 
acrylamide level was 4 weight percent and the glyoxal level was varied, as 
indicated in the table below, were used to bond nonwoven rayon webs. The 
bonded webs were tested as in Example 4 with the results given in the 
table below. 
TABLE II 
__________________________________________________________________________ 
XMD Tensile 
Strength (oz./in.) 
Wash Wet 
Sample.sup.a 
Composition 
AM/GL.sup.b 
Cycles 
Dry 
Water 
PCE 
IPA 
__________________________________________________________________________ 
Ex. 8 
95.2EA/4AM/0.8GL 
4.0 9 22 9.2 13 10 
Ex. 9 
94.8EA/4AM/1.2GL 
2.7 9 22 10 12 10 
Ex. 10 
94.4EA/4AM/1.6GL 
2.0 8 22 11 13 13 
Ex. 11 
93.6EA/4AM/2.4GL 
1.3 3 20 10 13 13 
__________________________________________________________________________ 
.sup.a Applied at 15% polymer bath solids with 0.5% NH.sub.4 NO.sub.3 
catalyst. Webs were airdried and cured at 300.degree. F./2 min. 
.sup.b Molar ratio indicated. 
The web bonded with the polymer containing the highest glyoxal level, 
Example 11, has less wash durability than the others. 
EXAMPLES 12-16. EFFECT OF VARYING ACRYLAMIDE LEVEL 
Using the thermal process, as in Example 1, polymers were prepared in which 
the acryalmide to glyoxal molar ratio was held at 3 and the acrylamide 
level was varied as given in the following table. Bonded webs were 
prepared and tested as in Example 4, with the results given in the 
following table. 
TABLE III 
__________________________________________________________________________ 
XMD Tensile 
Strength (oz./in.) 
Wash Wet 
Sample.sup.a 
Composition Cycles 
Dry 
Water 
PCE 
IPA 
__________________________________________________________________________ 
Ex. 12 
97.46EA/2.0AM/0.54GL 
8 22 9.2 13 8.4 
Ex. 13 
96.19EA/3.0AM/0.81GL 
7 22 9.2 11 9.2 
Ex. 14 
94.92EA/4.0AM/1.08GL 
7 24 9.2 10 11 
Ex. 15 
93.65EA/5.0AM/1.35GL 
6 24 8.8 12 11 
Ex. 16 
92.38EA/6.0AM/1.62GL 
6 24 9.6 12 12 
__________________________________________________________________________ 
.sup.a Applied at 15% polymer bath solids with 0.5% NH.sub.4 NO.sub.3 
catalyst. Webs were airdried and cured at 300.degree. F./2 min. 
EXAMPLES 17-22. POLYMERS CONTAINING ITACONIC ACID 
Using the procedure of Example 1, polymers were made incorporating itaconic 
acid at three levels and acrylamide at two levels also utilizing two 
values of the acrylamide glyoxal ratio. One polymer was also made by a 
redox polymerization process. The preparation of the bonded webs and the 
testing was as in Example 4 with the results being given in the table 
below. 
TABLE IV 
__________________________________________________________________________ 
XMD Tensile 
Strength (oz./in.) 
Washes Wet 
Sample.sup.a 
Composition AM/GL.sup.b 
Survived 
Dry 
Water 
PCE 
IPA 
__________________________________________________________________________ 
Ex. 17 
93.4EA/4.0AM/1.6GL/1.0IA 
2 10 24 10 13 11 
Ex. 18.sup.c 
93.4EA/4.0AM/1.6GL/1.0IA 
2 7 22 8.0 13 9.6 
Ex. 19 
93.92EA/4.0AM/1.08GL/1.0IA 
3 7 25 9.6 10 8.4 
Ex. 20 
93.15EA/5.0AM/1.35GL/0.5IA 
3 7 26 8.8 13 10 
Ex. 21 
92.65EA/5.0AM/1.35GL/1.0IA 
3 6 26 9.6 14 10 
Ex. 22 
92.15EA/5.0AM/1.35GL/1.5IA 
3 7 25 9.6 13 11 
__________________________________________________________________________ 
.sup.a Applied at 15% polymer bath solids with 0.5% NH.sub.4 NO.sub.3 
catalyst. Webs were airdried and cured at 300.degree. F./2 min. 
.sup.b Molar ratio indicated. 
.sup.c Prepared by a oneshot redox polymerization process differing from 
the preparation of Example 5 as follows: All of the monomers are 
incorporated in the kettle charge at 35% (total monomers) in water. 
Initiation is at 20.degree. C. 
EXAMPLES 23-25. EXPERIMENT WITH POST ADDED GLYOXAL 
A polymer of the composition of Example 2, omitting the glyoxal, is 
prepared by the process of Example 5, and divided into three aliquots. In 
Example 23, the aliquot is used as is; in Example 24, glyoxal is post 
added at the level of 1/2 mole per mole of acrylamide; and in Example 25, 
glyoxal is post added at the same level in addition to which the latex is 
heat aged at 140.degree. F. for 70 hours. Each aliquot is then used to 
bond a nonwoven rayon web and tested by the procedure outlined in Example 
4. 
The heat age sample was heat aged before the addition of the ammonium 
nitrate catalyst. The results show that post addition of glyoxal has 
comparatively little effect on the properties of the bonded fiber, 
however, heat aging after post adding the glyoxal does produce a marked 
improvement in the properties of the bonded fiber although not to the 
level achieved with the coreacted glyoxal in Example 2. It is recognized 
that in all three of these examples, there may have been a limited amount 
of crosslinking by mechanisms not involving the amide or the glyoxal. 
It is to be understood that changes and variations may be made without 
departing from the spirit and scope of this invention which is defined by 
the appended claims.