Antistatic films

A hydroxyorganosilane composition which upon curing provides a polymer that is an electrical conductor is disclosed. The composition comprises 1 to 95 weight percent of a hydrolyzate of a hydroxyorganosilane and optionally up to 50 weight percent of a silanol-sulfonate compound. When the cured polymer, which has a siloxane backbone, is a film in a composite structure, the resultant article has antistatic properties.

DESCRIPTION 
TECHNICAL FIELD 
The present invention relates to a hydroxyorganosilane composition which 
upon curing provides a polymer that is electrically conductive. When the 
cured polymer is a film in a composite structure, the resultant article 
has antistatic properties. Methods of preparing the conducting composition 
and composite structure are disclosed. 
BACKGROUND ART 
Many organic materials, especially polymers and polymeric films, display a 
decided tendency to acquire an electrostatic charge when handled or 
processed. This results in a number of known practical difficulties, for 
example, in manufacturing operations and subsequent uses. The prior art 
has dealt with the control of static charges by bleeding them off using 
conductive materials as antistatic agents. Varying degrees of success have 
been obtained with inorganic metallic foils, vacuum metallizing, and 
conductive coatings on polymeric substrates. 
Polymers having antistatic properties have been prepared by free-radical or 
cationic polymerization of certain vinyl monomers. U.S. Pat. No. 4,248,750 
relates to a linear siloxane with pendant vinyl groups that crosslinks by 
hydrosilation to provide a polymer having both silane-type and carbon-type 
linkages in its backbone. W. German Offenlegungsschrift No. 2,051,832 
discloses a vinyl monomer copolymerized with a silanol-containing vinyl 
monomer, hydrolyzed with sulfuric acid, and then cured to produce an 
antistatic polymer having a large proportion of carbon to carbon linkages 
in its backbone. 
Also known in the art are polymers having antistatic properties which have 
been prepared by polymerization through a silicon functionality. In U.S. 
Pat. No. 4,294,950 monomers having silane and epoxide functionality are 
subjected to hydrolysis of the silane moieties to provide silanols. 
Polymerization and curing in the presence of polyvalent carboxylic acids 
and curing agents provide polymers having backbone polyester and siloxane 
groups. 
Antistatic prior art materials frequently suffer from a serious performance 
deficiency; namely, a critical dependence of conductivity on relative 
humidity. Prior art materials, other than metal-like conductors, provide 
little, if any, static protection below 20 percent relative humidity. Many 
such materials impart a greasy feel to the article and the antistatic 
performance can be adversely affected by washing with solvents. These 
materials frequently exhibit inadequate abrasion resistance, durability, 
and transparency. There remains a need in the art for polymeric materials 
having antistatic properties at very low relative humidities. 
Dilute aqueous solutions of certain terminal monohydroxy-substituted 
organosilanols have been disclosed in U.S. Pat. No. 3,161,611 as useful 
for impregnation of paper, textiles, leather and other materials. Coating 
compositions comprising these silanols are not described. Aqueous di- or 
polyhydroxy-substituted organosilanols, with or without silanol-sulfonate 
compounds, are novel in the art. The cured coated compositions of any of 
the above materials have not been previously disclosed. 
DISCLOSURE OF THE INVENTION 
Briefly, the present invention provides a composition comprising a 
hydroxyorganosilane, and optionally, a sulfonic acid-substituted 
organosilane, which cures to a transparent, durable, conductive polymer 
having a siloxane backbone and which has antistatic properties even at 
relative humidities of 7 percent or lower. 
In another aspect, the present invention provides a conductive composite 
structure comprising: (1) a suitable substrate coated on at least one 
surface with (2) a composition comprising the cured reaction product of a 
hydroxyorganosilane and, optionally, a sulfonato-organosilicon compound. 
The conductive composite can be optionally overcoated on any exposed 
surface with another film. A substrate coated with the conductive film of 
the present invention is useful to remove or draw-off static electric 
charges, has an electrical conductivity which is relatively independent of 
humidity, and can possess both antifogging characteristics and cation 
exchangeability. The conductive composite structure, when comprising an 
overcoated polymeric film having specific properties can possess 
additional desirable characteristics, such as high abrasion resistance, 
imageability, or adhesiveness. Surprisingly, such constructions retain 
superior surface conductivities even though the overcoating film is 
non-conductive. 
In another aspect, the present invention provides conductive polymeric 
compositions which are prepared by the condensation polymerization of 
hydroxy and polyhydroxy group-containing organic monomers from essentially 
aqueous solution, preferably using acid catalysts to help promote 
polymerization. During the condensation reaction water is removed from 
sulfonated or non-sulfonated hydroxyalkyl-substituted silanols, 
siloxanols, or oligomers thereof, or polysiloxanes containing silanol 
groups or hydrolyzable protected silanol groups. The use of acid catalysts 
in curing the monomers of this invention is desirable even when the 
monomers contain "built-in" acidic groups such as sulfonic acid groups. On 
curing, these monomers form hard, solvent resistant, conductive polymeric 
films of high dielectric constant which are useful for drawing off 
potential static charges, function relatively independently of humidity 
(surprisingly, even down to a relative humidity of 7 percent or lower), 
and may possess antifogging characteristics. 
As used in this application: 
"hydroxyorganosilane" means any organic group-substituted silane, wherein 
the organic group is covalently attached to a silicon atom through a 
carbon atom, and wherein the organic group has at least one attached 
hydroxy group; 
"sulfonato-organosilicon compound", often referred to herein as 
silanol-sulfonate, means any organic group-substituted silane, wherein the 
organic group is covalently attached to a silicon atom through a carbon 
atom, and wherein the organic group has at least one attached sulfonic 
acid group (or its salt form); 
"solution" means mixtures and compositions wherein water is present. Such 
solutions may use water as the only solvent, or they may employ 
combinations of water with water-miscible organic solvents such as alcohol 
and acetone. Further, substantial amounts of organic solvents may be 
included in the combinations; 
"film" means a cured, polymerized organic composition; 
"cured" means crosslinked to a three-dimensional structure; 
"coating composition" means an uncured organic composition; and 
"exhaustive hydrolysis" means a reaction of hydrolyzable groups with water 
at low pH, preferably of pH less than 2, to generate a hydroxy-substituted 
group. 
The present invention provides for the preparation and application of low 
cost organosilanes which upon curing provide polymers having excellent 
conductivity and abrasion-resistance which extends their applications 
beyond the limits of typical antistatic agents. The polymeric compositions 
described in this invention show excellent durability in terms of both 
solvent and abrasion resistance. The cured polymers of this invention are 
clear, tintable, and flexible, and they are easily prepared and applied. 
Moreover, these materials function not only as excellent top coatings in 
antistatic and antifogging applications, but they also display conductive 
properties as undercoatings or sub-layers in composite constructions in a 
variety of applications wherein surface charges need to be electrically 
grounded or dissipated. 
While there is no clear division between conductive and resistive films, it 
is generally considered that a material having a resistivity of greater 
than 10.sup.13 ohms per square (ohms/sq) shows insulating properties, 
while a material having a resistivity of less than 10.sup.13 ohms/sq 
exhibits conductive properties. 
The conductive polymeric films of the invention may be self-supporting or 
they may be formed by coating a composition onto a substrate and curing 
this coating to form the conductive polymeric film. Optionally, 
overcoating compositions can be incorporated in the composite structure. 
One or more compositions can be overcoated onto either surface of the 
conductive film-coated substrate and then cured. For example, an optional 
overcoating can be a highly abrasion resistant polymeric film, a 
photographic film, an adhesive layer, a dielectric layer, or a low 
adhesion backsize. 
DETAILED DESCRIPTION OF THE INVENTION 
The present invention provides a composite structure comprising: 
a. a substrate, 
b. a cured film on at least one surface of said substrate, said film 
comprising a cured hydroxyorganosilane, and optionally an organic 
group-substituted silane, wherein said organic group is covalently 
attached to a silicon atom through a carbon atom, and wherein said organic 
group has at least one sulfonic acid group, or its salt form, attached 
thereto, and 
c. optionally, a second continuous or discontinuous layer may be adhered on 
any exposed surface. 
Preferably, the curable hydroxyorgaosilane composition of the present 
invention is coated upon a substrate and subjected to in situ energy 
curing. 
The coating composition of the present invention comprises: 
1. 1 to 95 weight percent of a silane hydrolyzate derivative of an 
organosilane dissolved in 5 to 99 weight percent of an aqueous solvent, 
said organosilane having the general formula 
EQU R.sup.1 --Si(OR.sup.2).sub.3 I 
wherein R.sup.1 is a hydroxy- or polyhydroxy-substituted organic group 
preferably selected from: 
a. alkyl groups having from 2 to 8 carbon atoms and substituted by 1 to 7, 
and preferably 2 to 7, hydroxy groups, with any single carbon atom having 
at most one hydroxy group attached; 
b. alkyl groups and cyclic alkyl groups having up to 20 carbon atoms, which 
carbon chain may be interrupted by one or more oxygen atoms and containing 
at least one, and preferably at least 2, hydroxy group per 8 carbon atoms, 
with any single carbon atom having at most one hydroxy group attached; 
c. aralkyl or alkaryl groups containing 7 to 10 carbon atoms, said aralkyl 
or alkaryl group having 1 to 8, and preferably 2 to 8, hydroxy groups, 
with any single carbon atom having at most one hydroxy group attached; 
d. alkenyl group containing up to 8 carbon atoms and 1 to 5, and preferably 
2 to 5, hydroxy groups, with any single carbon atom having at most one 
hydroxy group attached; 
e. cyclic or alkyl-substituted cyclic groups having up to 8 carbon atoms 
and substituted by 1 to 7, and preferably 2 to 7, hydroxy groups, with any 
single carbon atom having at most one hydroxy group attached; and 
f. those precursor groups such as epoxy, ketal, acetal and ester which, on 
exhaustive hydrolysis, provide the aforementioned hydroxy, and preferably 
dihydroxy or polyhydroxyalkyl, groups. 
Wherever the term "group" is used in the definition of a term (as in alkyl 
group versus alkyl), the term connotes the possibility of substitution 
recognized by the art as not affecting the functional nature of the 
chemical term. Where the term "aralkyl or alkaryl group" is used, 
unsubstituted or substituted phenyl is anticipated, and substituent groups 
include, for example, lower alkyl of 1 to 4 carbon atoms, nitro, halo, 
cyano, hydroxy, and ether groups, with no more than one substituent group 
on any carbon atom of the phenyl group. 
R.sup.1 most preferably is a dihydroxy-substituted alkyl group containing 4 
to 8 carbon atoms whose chain may be interrupted by one or two oxygen 
atoms or the appropriate hydroxy precursor which on exhaustive hydrolysis 
gives the most preferred R.sup.1 group; and 
R.sup.2 is selected from (1) hydrogen, and (2) any organic group such that 
the --Si(OR.sup.2).sub.3 moiety is hydrolyzable. For example, useful 
groups include straight chain or branched alkyl, alkaryl, acyl, or aroyl 
group having up to 8 carbon atoms which allows hydrolysis of the 
--Si(OR.sup.2).sub.3 moiety to give a silanol hydrolyzate or oligomers 
thereof. Useful groups include methyl, ethyl, octyl, methoxyethyl, acetyl, 
phenyl, benzyl, and benzoyl. 
Organosilanes in which R.sup.1 is a dihydroxy-substituted alkyl group is 
most preferred due to the ease of preparation of these materials and the 
ready availability of starting materials. 
Examples of organosilanes having the general Formula I above are: 
##STR1## 
2. From 0 up to about 50 weight percent of a sulfonato-organosilicon 
compound (referred to hereinafter as silanol-sulfonate) may be added, said 
silanol-sulfonate compound having the general formula 
##STR2## 
wherein Q is selected from hydroxyl, alkyl groups containing from 1 to 4 
carbon atoms, and alkoxy groups containing from 1 to 4 carbon atoms; 
X is an organic linking group; 
Y is any organic or inorganic cation. Preferably Y is selected from 
hydrogen, alkali metals (e.g., lithium, sodium, potassium), alkaline earth 
metals (e.g., magnesium, calcium), transition metals (e.g., manganese, 
cobalt, copper, zinc), heavy metals (e.g., lead), organic cations of 
protonated weak bases having an average molecular weight of less than 
about 400 and a pK.sub.a of less than about 11 (e.g., 4-aminopyridine, 
2-methoxyethylamine, benzylamine, 2,4-dimethylimidazole, 
3-[2-ethoxy(2-ethoxyethoxy)]propylamine), and organic cations of strong 
organic bases having an average molecular weight of less than about 400 
and a pK.sub.a of greater than about 11 [e.g., .sup.+ P(CH.sub.2 C.sub.6 
H.sub.5)(C.sub.6 H.sub.5).sub.3, .sup.+ N(CH.sub.3).sub.4, .sup.+ 
N(CH.sub.2 CH.sub.3).sub.4 ]; most preferably Y is hydrogen; 
r is equal to the valence of Y; and 
n is 1 or 2; with the proviso that the mole ratio of silanol-sulfonate to 
organosilane is less than 5 to 1. 
X is any organic linking group containing up to 10 carbon atoms and not 
functionally involved in the polymerization of the molecule. Preferably X 
is selected from alkylene groups having at least two or more methylene 
groups, cycloalkylene groups, alkyl-substituted cycloalkylene groups, 
hydroxy-substituted alkylene groups, hydroxy-substituted mono-oxa alkylene 
groups, divalent hydrocarbon groups having mono- or poly-oxa backbone 
substitution, divalent hydrocarbon groups having mono-thia backbone 
substitution, divalent hydrocarbon groups having dioxo-thia backbone 
substitution, divalent hydrocarbon groups having monooxo-thia backbone 
substitution, arylene groups, arylalkylene groups, alkylarylene groups, 
substituted alkylarylene groups, and alkylarylalkylene groups. Most 
preferably, X is selected from alkylene groups having at least two or more 
methylene groups or such hydroxy-substituted alkylene groups and 
hydroxy-substituted mono-oxa alkylene groups having a total of up to 10 
carbon atoms. 
Where a silanol-sulfonate compound is used it is present in the range of 
0.001 to 50 weight percent. 
Organosilanol-sulfonic acids are a preferred class of compounds within 
Formula II and are present in the most preferred coating solutions and 
films of the present invention. These compounds have the formula 
##STR3## 
wherein Q, X and n are each as described above. Examples of 
organosilanol-sulfonic acids of Formula III are 
EQU (HO).sub.3 --Si--X--SO.sub.3.sup.- H.sup.+ (IIIA) 
##STR4## 
In these formulae, X is as described above and Q' is an alkyl group which 
contains from 1 to 4 carbon atoms. Representative compounds or oligomers 
of Formulae III(A-C) include: 
##STR5## 
Of these specific compounds, those of formulae (a), (c), (d) and (i) are 
preferred, with compound (a) being particularly preferred. Useful starting 
materials in the preparation of compounds (a) through (i) above are 
disclosed in U.S. Pat. No. 4,235,638, col. 6, and the starting material of 
compound (j) is disclosed in U.S. Pat. No. 2,968,643 (Exs. IV and V), both 
patents being incorporated herein by reference. 
The aqueous solutions of the organosilanolsulfonic acids are acidic and 
they usually have a pH of less than about 5. Preferably, they have a pH of 
less than about 3. Most preferably, they have a pH in the range of about 
0.5-2.5. 
Organosilanol-sulfonic acid salts represent another class of compounds 
within Formula II which are useful in either or both the solutions and 
cured compositions of the present invention. These compounds are 
well-known in the art and have the formula 
##STR6## 
wherein X, n and r are each as described above, Q" is selected from 
hydroxyl and alkyl groups containing from 1 to 4 carbon atoms, and Y is as 
described above except Y is not hydrogen. Examples of 
organosilanol-sulfonic acid salts of Formula IV are: (a) (HO).sub.3 
Si-CH.sub.2 CH.sub.2 SO.sub.3.sup.- K.sup.+, (b) (HO).sub.2 Si-(CH.sub.2 
CH.sub.2 SO.sub.3.sup.- Na.sup.+).sub.2, (c) (HO).sub.3 SiCH.sub.2 
CH.sub.2 CH.sub.2 SO.sub.3.sup.- N.sup.+ (C.sub.2 H.sub.5).sub.4, and (d) 
(HO).sub.3 SiCH.sub.2 CH.sub.2 CH.sub.2 O-CH.sub.2 CH(OH)CH.sub.2 
SO.sub.3.sup.- Ba.sub.1/2.sup.+2. 
The aqueous solutions of the organosilanol-sulfonic acid salts are 
approximately neutral. Thus, they have a pH in the range of about 5 to 9. 
Compounds represented by Formulae I, II, III, and IV above may also exist 
as oligomers in aqueous solution and are useful as such in the present 
invention. 
Optionally, monomeric or polymeric alkyl-, aryl-, alkaryl-, and 
aralkyl-sulfonic acids having up to 20 carbon atoms per sulfonic acid 
group (e.g., dodecylbenzenesulfonic acid, benzenesulfonic acid, 
ethanesulfonic acid, polystyrenesulfonic acid, and methanesulfonic acid) 
or the salts of such acids may be used. However, they do not normally 
provide the water or solvent durability that is provided by preferred 
co-reacted silanol-sulfonate materials, i.e., simple sulfonic acids tend 
to migrate or be leached out of the cured conductive film. However, once 
the conductive polymeric film is overcoated with an abrasion resistant 
film, for example, the conductive polymeric film is relatively impervious 
to the leaching effects of water. Phosphonic acids with structures similar 
to those of the sulfonic acids described above are also useful. 
The function of the preferred sulfonic acids is not only to provide 
sulfonate functionality, but also to serve as an acid in promoting the in 
situ exhaustive hydrolysis of any hydroxyl precursor, as described above, 
to its corresponding alcohol. Such hydrolytic processes may be exothermic 
and can be monitored by spectroscopic means, as for example, by infrared 
and nuclear magnetic resonance spectroscopies. 
3. Optionally, an Acid Catalyst 
Use of an acid catalyst is usually desirable particularly to afford hard, 
solvent resistant films. Any acid catalyst which speeds up the curing of 
the hydroxyorganosilane composition is useful. Useful acid catalysts 
include inorganic acids as, for example, sulfuric acid, nitric acid, 
phosphoric acid, antimony pentafluoride, antimony pentachloridedimethyl 
methylphosphonate (see U.S. Pat. No. 4,293,675), hexafluoroantimonic acid 
and such acidic organic materials as, for example, p-toluenesulfonic acid 
and other monomeric or polymeric sulfonic acids, 
bis(perfluoromethanesulfonyl)methane (see U.S. Pat. No. 2,732,398), higher 
homologs of such fluorinated sulfonyl methanes (see U.S. Pat. Nos. 
3,281,472, 3,632,843 and 4,049,861), trifluoromethanesulfonic acid and 
higher perfluorinated homologs (see U.S. Pat. No. 4,049,861), and 
photoactivatable initiators such as, for example, triarylsulfonium 
hexafluoroantimonate and similar compounds (see U.S. Pat. No. 4,173,476). 
These catalysts can be present in concentration ranges from about 1 to 
about 5 weight percent based on the percent solids of the total reactive 
monomers. Hexafluoroantimonic acid hexahydrate is a preferred catalyst. 
Substrates useful in the present invention are fibers, sheets and the 
surfaces of shaped solid objects. Among the preferred substrates are 
ceramic materials (e.g., glass, fused ceramic sheeting, fibers, and 
particulates such as silica), metals (e.g., sheets, fibers, aluminum, 
iron, silver, chromium, nickel, brass and other metals), metal oxides, 
thermoplastic resins (e.g., polymethyl methacrylate, polyethylene 
terephthalate, cellulose acetate and cellulose acetate butyrate), 
polycarbonates, polyamides and polyolefins (e.g., polystyrene, 
polyethylene and polypropylene), acrylic resins, polyvinyl chloride, 
polysilanes, polysiloxanes, thermoset resins, epoxy resins, paper, wood 
and natural resins (e.g., rubber, gelatin and silver halide-gelatin 
emulsions), textiles, foams, laminates, coated articles, and other organic 
and inorganic substrates, any surface of which may benefit from a coated 
conductive polymeric film. 
When the substrate is not naturally adherent with the compositions of the 
present invention, the substrate may be primed first. Many primers are 
known in the art, and their purpose is to provide a layer to which the 
conductive film more readily adheres than to the original surface of the 
substrate. For example, in the photographic art, primers are generally 
used on the polyethylene terephthalate base to improve adhesion of 
subsequent layers thereto. A host of commercial primers such as 
polyvinylidene chloride, various aliphatic or aromatic urethanes, 
caprolactones, epoxies, and siloxanes can also find utility as primers for 
the films of the invention. The surface of the substrate may itself be 
modified to improve adherence. 
Specific substrates used in the present invention include aluminum that was 
previously silicated, brass that was previously treated with a nitric 
acid-ferric chloride solution, polyethylene that was previously chromic 
acid etched [see J. R. Rasmussen, E. R. Stedronsky and G. M. Whitesides, 
J. Amer. Chem. Soc. 99, 4737 (1977)], polypropylene which is chromic acid 
etched or previously subjected to corona discharge, glass which is either 
first abraded with a scouring powder or etched with chromic acid, and 
cellulose acetate butyrate which is first treated with caustic (sodium 
hydroxide or potassium hydroxide). Polyvinylidene chloride-primed 
polyethylene terephthalate (commercially available from 3M) is a 
particularly suitable substrate used in this invention. 
Additives which serve a given purpose such as viscosity modifiers, hardness 
modifiers, pigments, fillers, UV absorbers, colorants, leveling agents, 
and the like, may be added with proper mixing. A leveling agent which has 
been found useful in the practice of the present invention is Triton 
X-100.RTM., octylphenoxypolyethoxyethanol (Rohm and Haas, Philadelphia, 
PA). Leveling agents are used in trace to minor amounts, e.g., 0.001 to 
1.0 weight percent. Optional additives include numerous organosilane and 
organosiloxane monomers and oligomers, for example, methylsilanetriol 
oligomers, orthosilicates, and those materials represented by the formula: 
##STR7## 
wherein R.sup.1 and R.sup.2 are defined above and R.sup.3 is selected from 
alkyl groups having 1 to 6 carbon atoms or phenyl groups, a is 2 or 3, and 
b is 1 or 2, with the proviso that (a+b) is equal to 3 or 4. Additives may 
be added based on the percent solids of the reactive monomers and may vary 
from as little as 0.1 to as much as 20 percent or more. Epoxysilanes are 
particularly useful additives for the preparation of hard and abrasion 
resistant films. They may be used in amounts in the range of 0.1 to up to 
95 weight percent of reactive monomers. 
The pH range of these formulations can be from about 0.5 to about 11, 
depending upon the selection of components. Since there is a correlation 
between higher conductivity and lower pH, subsequent addition of basic 
additives to the preferred acidic formulations is limited so that the pH 
of the resulting coating formulation remains less than about 5, preferably 
less than about 3, and most preferably less than about 2. This also 
encourages a curing rate which is not excessively slow and also provides 
hard, solvent resistant films. Solvents may be added to adjust the 
viscosity of the uncured solution. These compositions are usually, and 
preferably, used shortly after they are prepared; however, they may be 
prepared and stored at room temperature or below for several days before 
application. 
To prepare the composite structure of the present invention, solutions of 
the components of the coating composition, i.e., the organosilane 
hydrolyzate, the optional silanol-sulfonate and the optional acid catalyst 
are simply mixed or blended. This mixture is allowed to stand until 
exhaustive hydrolysis, where necessary, is complete. Heating may be 
required. The preferred order of addition of ingredients is to add the 
silanol-sulfonate to the silane. 
The solution is applied to a substrate, which can be in the shape of a 
polymeric film, or a preformed article made of, for example, 
polyvinylidene chloride-primed polyethylene terephthalate, by dipping, 
brushing, spraying, knife coating, bar coating, and painting, or by any 
other suitable coating method. A coating method conveniently used in this 
invention employs RDS bar coaters (RD Specialties, Webster, NY) which 
allow the coating of resultant films of specified thicknesses. Cured 
coating thicknesses of about 0.1-25 microns are particularly useful, with 
a thickness in the range of about 1-10 microns being preferred. Where 
desired, thicker coatings can be applied. 
The composition of the present invention coated on a substrate can be cured 
in situ by heat or microwave radiation which causes polymerization of the 
coated compositions of the present invention, and will provide hard, 
solvent resistant films provided such films are adequately dehydrated 
during the curing process. 
The preferred method of curing these coatings is by application of heat 
with temperatures ranging from about 60.degree.-120.degree. C.; more 
preferably the temperature is in the range of about 80.degree.-100.degree. 
C. Higher or lower temperatures can be used. The duration of curing ranges 
from as short as about 2 minutes to as long as about 16 hours, with a 
preferred curing time of about 30 minutes at 90.degree. C. 
It is preferable that both radiation and heat be used to cure the coating 
compositions when a triphenylsulfonium hexafluoroantimonate or similar 
photoactivatable material is used, as described in U.S. Pat. No. 
4,173,476. Neutral coating compositions containing photoactivatable 
catalysts have the advantage of longer shelf life than those containing 
added acidic materials. Any suitable source which emits actinic radiation 
and preferably ultraviolet radiation may be used to activate these 
catalysts in the practice of this invention. Suitable sources are mercury 
arcs, carbon arcs, low-, medium-, and high-pressure mercury lamps, plasma 
arcs, ultraviolet light emitting diodes, and ultraviolet emitting lasers. 
Typical cure conditions with such ultraviolet light sources involve the 
conveying, or repeated conveying, of an overcoated substrate several 
centimeters from the source of a 200 watt per 2.54 cm (1 inch) 
medium-pressure mercury vapor lamp preferably in a reflectorized housing 
for maximum radiation exposure with, optionally, a conveyor moving at a 
suitable speed, for example, 15 meters/minute (50 feet per minute). 
Another convenient means of preparing cured polymeric compositions which 
incorporate the optional silanol-sulfonate salt of Formula IV involves the 
preparation of cured films comprising the silanol-sulfonic acids described 
above and subsequently replacing the proton of the sulfonic acid groups in 
the cured films by a desired cation. One method involves the 
ion-exchanging of the desired cation into a film by immersion of the cured 
film into a solution of a neutral or basic salt of the desired cation. 
Another method, for example, is to form protonated weak bases as the 
cationic species by reaction of the sulfonic acid groups in the cured film 
with a weak base having a pK.sub.a of less than about 11. Again, this may 
be accomplished by immersion of a cured film into a solution of the weak 
base. Conversely, by ion-exchange methods, silanol-sulfonate 
salt-containing films may be converted to silanol-sulfonic acid-containing 
films by immersion in protonic acid solution. Furthermore, the cations of 
the silanol-sulfonate salt-containing films may be interchanged. 
It may be desirable to modify the surface of the cured polymeric conductive 
film by lowering its coefficient of friction and thereby imparting certain 
desirable handling qualities. This can be accomplished by applying, for 
example, fluorocarbons, release agents, or antiblocking agents to the film 
by methods such as those taught in U.S. Pat. No. 4,293,606. 
Surprisingly, overcoating a first cured conductive film of this invention 
with another compatible film which itself is not conductive provides novel 
composite films of excellent conductivity. The first cured conductive film 
of the present invention may also be overcoated with a second similar or 
identical film within the present invention to afford a conductive 
composite structure having additional desirable properties, such as 
abrasion resistance. The second coating formulation or top coating may be 
selected so as to provide different conductive or other properties in the 
cured top layer. 
Polymeric overcoatings which may be useful can be derived from a variety of 
silane monomers and their hydrolyzates (or their respective oligomers or 
polymeric forms, alone or in combination). Typical examples include: 
##STR8## 
Methods of coating and the subsequent acid catalyzed curing of these silane 
materials to produce cured siloxane films are described in the art. They 
may be applied from organic solvents or water and may be modified by the 
incorporation of various additives such as viscosity modifiers, pigments, 
fillers, UV absorbers, colorants, leveling agents and the like. 
The coating and overcoating compositions may be applied to a substrate or 
to a previously prepared conductive polymeric film coated substrate by 
dipping, brushing, spraying, knife coating, bar coating, painting, or by 
any other suitable coating method. The coating method conveniently used in 
this invention employs RDS bar coaters (RD Specialties, Webster, NY) which 
allows for the coating of compositions of specified thicknesses. The 
coating thickness of the overcoating composition depends on the use of the 
desired composite film. The practical upper limit of thickness of the 
overcoated film depends on the nature of its construction and requires 
that the resultant composite structure remains intact after curing. 
Curing of the overcoating composition can be accomplished in situ by 
employing any energy source appropriate to the specific monomer or 
monomers present. 
It has been found, surprisingly, that when, for example, a polyvinylidene 
chloride-primed polyethylene terephthalate substrate having a conductive 
polymeric film thereon has an overcoated abrasion resistant polymeric film 
derived from acid catalyzed curing of 
gamma-glycidoxypropyltrimethoxysilane (see Example I below), the resultant 
composite polymeric film still exhibits good conductivity. It has been 
found, further, that the conductivity of such composites is essentially 
independent of the thickness of the abrasion-resistant overcoated 
polymeric film, within practical coating capabilities. Furthermore, the 
abrasion-resistance of these composite films is excellent, as indicated by 
abrasion-resistance haze tests. 
Additional overcoatings which may be employed in the practice of this 
invention include numerous surface-modifying siloxane coatings, for 
example, release coatings, adhesives, and protective coatings which are 
well documented in the art. See, for example, U.S. Pat. Nos. 4,049,861, 
4,225,631, 4,239,798 and 4,223,121 which relate to abrasion resistant 
coatings, and U.S. Pat. No. 3,986,997 which discloses pigment-free coating 
compositions. U.S. Pat. No. 4,239,798 describes a silicone coated 
polycarbonate article and U.S. Pat. No. 4,101,513 discloses a catalyst for 
condensation of hydrolyzable silanes and storage stable compositions 
thereof. U.S. Pat. No. 4,294,950 relates to a coating composition 
comprising hydrolyzates from silane compounds. 
Many of the characteristics of these polymeric films combine to provide 
materials with unique and useful properties. During normal use, these 
films may come in contact with water or abrasive materials or both. The 
films of this invention show excellent durability with respect to water 
washing or abrading with steel wool. In most instances, the abrasion 
resistance is superior to that of the uncoated substrate. In composite 
films, wherein the top layer is a cured siloxane abrasion resistant layer, 
the hardness may be such that the conductive cured coatings are scratched 
with steel wool only with difficulty. A quantitative measure of this 
surface hardness is a film's resistance to abrasion by falling sand. 
Conductivity of the films is readily apparent in their excellent antistatic 
properties. Surface charges cannot only damage electrical components, but 
also may attract contaminants such as dust and smoke particles. When 
buffed with a tissue, for example, the surfaces of films of this invention 
do not attract small pieces of tissue, paper, cigarette ashes or 
polystyrene, even down to very low humidities. Static decay times (as 
shown in examples below) illustrate the reluctance of films to develop or 
maintain static charges. 
Films particularly useful are those having silanol-sulfonates or sulfonato 
functional organic compounds since they resist fogging. For example, such 
films, when breathed on, resist fogging, even if they are initially cooled 
by refrigeration. 
The ion exchange characteristics of those polymeric films containing the 
silanol-sulfonato component allow easy, rapid tinting, even at room 
temperature. By simple ion exchange of the sulfonato groups with the 
appropriate cationic dye, such films may be selectively colored to almost 
any optical density by immersion of the cured coating into a solution of 
the dye. 
The cured conductive compositions of the present invention are useful as 
coatings in composite structures as well as self-supporting cured 
conductive films. The cured compositions dissipate charges, provide 
conductive surfaces in imaging technology, serve as a ground plane, may 
prevent fogging, and may exchange and bind ions. They are useful with any 
compatible film or material which might benefit from the use of a 
conductive sub- or under-layer to dissipate or transport electronic 
charge. Examples of such films or materials are adhesives, gelatins, 
photoemulsions, photoconductive materials and dielectric materials. 
Evaluation of various physical properties of the cured compositions of the 
present invention were made. In the evaluation of surface resistivity, 
razor blades were used as flexible electrodes and made excellent contact 
with the polymeric films. The blades were connected to an insulating 
polymer platform and were attached by use of spring loaded clamps to 
insure intimate contact with the substrate surface. The configuration was 
such that the edges of the blades were diametrically opposed and, thus, 
described a square-shaped area of approximately 16 cm.sup.2. Electrical 
contact was made by attachment with coaxial cable from a Keithley 600A 
electrometer (Keithley Instruments, Inc., Cleveland, OH) to the metallic 
spring clamps holding the blades. 
Conductivity measurements are sometimes made at ambient relative humidity. 
To demonstrate the superior performance of the films of this invention 
under adverse conditions, they were often evaluated at low relative 
humidity. The electrodes of the electrometer and the sample were kept in 
an enclosed chamber which had therein a material (see examples of useful 
materials in "Lange's Handbook of Chemistry", J. A. Dean, Editor, 
McGraw-Hill Publishers, New York (1973) 11th Edition, page 10-79) which 
provided a specified relative humidity at a given temperature under the 
equilibrium conditions of a closed vessel. 
In the static decay evaluation, a sample of the film was charged up to 5000 
volts, grounded, and the time it took to discharge to 500 volts, was 
measured. Military specifications (MIL-B-81705) presently accept for 
static protection any film that exhibits a static decay time of two 
seconds or less. 
The abrasion resistance of polymeric films was measured by the film's 
resistance to abrasion by falling sand. One liter of sand 20 to 30 mesh, 
ASTM Designation C190-77, (Ottawa Silica Co., Ottawa, IL) was dropped 
through an abrasion tester instrument and the falling sand was allowed to 
impinge onto a film surface whose haze or light transmitting properties 
were measured before and after abrasion with sand using a Gardner 
Hazemeter as described in ASTM Method D1003-61 (1977). 
Objects and advantages of this invention are further illustrated by the 
following examples, but the particular materials and amounts thereof 
recited in these examples, as well as other conditions and details, should 
not be construed to unduly limit this invention. Parts and percentages are 
by weight unless otherwise indicated, and temperatures are in degrees 
centigrade. In the following examples, compositions that lead to 
conductive polymeric films were applied to substrates using an RDS Bar 
Coater No. 14, and overcoatings of abrasion resistant compositions were 
applied to conductive polymeric film-coated substrates using an RDS Bar 
Coater No. 8 (commercially available from RD Specialties, Webster, NY) 
unless indicated otherwise. All resistance measurements were made with a 
Keithley Instruments 600A electrometer (Keithley Instruments, Inc., 
Cleveland, OH). All resistivities are surface resistivities unless 
otherwise stated and are given for equilibrated samples at the relative 
humidity specified.

EXAMPLE 1 
Conductive polymeric films were evaluated for surface resistivity (or 
conductivity) using ASTM Method D257-78 as the model, and for static decay 
using Federal Test Method Standard No. 101, Test Method No. 4046 as the 
model. The polymeric films were prepared from a coating formulation 
comprising a mixture of a hydrolyzate solution of 
gamma-glycidoxypropyltrimethoxysilane (which solution is hereinafter 
referred to as A), with a silanol-sulfonic acid solution derived from 
gamma-glycidoxypropyltrimethoxysilane (which solution is hereinafter 
referred to as B) wherein the ratio of the two components of this mixture 
were varied as is indicated in samples 1-5 of Table I. 
The hydrolyzate solution, A, of gamma-glycidoxypropyltrimethoxysilane was 
prepared by agitation of a mixture of 20 g of this monomer with 10 g of 
water for about 90 minutes at ambient temperature. 
Solution B, the silanol-sulfonic acid solution derived from 
gamma-glycidoxypropyltrimethoxysilane, was prepared by slowly adding a 
solution of 29.5 g of gamma-glycidoxypropyltrimethoxysilane in 14.75 g of 
water to a solution of 15.75 g of sodium sulfite and 40 g of water. The 
mixture was stirred and reacted at 50.degree. C. for 16 hours. The pH of 
the resulting reaction mixture was 12.8. The solution was passed through 
an excess of the acid form of Amberlite.RTM.IR-120 (ion exchange resin, 
Rohm and Haas Company, Philadelphia, PA). This provided a solution having 
a pH of less than 1. The solution was adjusted to 23 percent solids by 
weight by addition of water. 
In a typical sample formulation, 3 g of A was combined with 1.5 g of B and 
the resulting solution was allowed to stand at room temperature until any 
exotherm subsided (about 10-15 minutes, see below). To this solution was 
added 2 ml of methanol, a few drops of a 10 percent solution of Triton 
X-100, and 40 mg (1-2 percent by weight) of hexafluoroantimonic acid 
hexahydrate. This formulation was coated on polyvinylidene chloride-primed 
polyethylene terephthalate using a No. 14 RDS Bar Coater. The resultant 
coating was then cured at 90.degree. C. for at least 30 minutes to give 
the polymeric film. 
The cationic methylene blue dye absorbance evaluation utilized a piece (1 
cm.times.1 cm.times.about 7 microns thick) of polymeric composite film, 
whose composition is described below. The film sample was immersed in 
0.01M aqueous methylene blue (as the chloride) for 15, 30, or 60 seconds, 
then rinsed with distilled water, and placed in a Beckman DB 
spectrophotometer where the absorbance was measured at a wavelength of 655 
nanometers (nm). A higher absorbance indicates the presence of a larger 
number of sulfonate groups which bind the methylene blue. 
TABLE I gives composition, resistivity, methylene blue absorbance, and 
static decay data for samples 1 to 5. 
TABLE I 
__________________________________________________________________________ 
Studies of Polymeric Films Derived from Glycidoxypropyltrimethoxysilane 
Silane-containing materials 
Methylene blue 
Static decay.sup.c (sec) 
Sample 
A B Wt. Ratio 
Resistivity.sup.a 
absorbance.sup.b 
Stored 
No. Wt. (g) 
Wt. (g) 
A/B (ohms/square) 
15 sec. 
30 sec. 
60 sec. 
Initial 
(11 days) 
__________________________________________________________________________ 
1.sup.d 
3.0 0.5 6 greater than 10.sup.13 
0.05 
0.05 
0.06 
0.24 
0.35 
2 3.0 1.0 3 10.sup.9e 
0.24 
0.30 
0.40 
0.04 
0.06 
3 3.0 1.5 2 10.sup.8 0.99 
1.28 
1.67 
0.06 
0.05 
4 3.0 2.0 1.5 10.sup.8 1.31 
1.64 
2.03 
0.05 
0.04 
5 3.0 3.0 1 10.sup.8 1.45 
1.83 
2.16 
0.05 
0.04 
__________________________________________________________________________ 
.sup.a measured at relative humidity of 28%; control polyester film had a 
resistivity greater than 10.sup.14 ohms/square 
.sup.b control films prior to exposure to methylene blue had an absorbanc 
of 0.05 at 655 nm 
.sup.c film stored and tested at 7% relative humidity; static decay time 
of control polyester substrate was too long for practical measurements 
(longer than minutes) 
.sup.d when the coating solution was heated for 1 hour at 60.degree. C., 
ensuring exhaustive hydrolysis, conductivity of the cured film was 4.3 
.times. 10.sup.9 ohm/square at 25 percent relative humidity 
.sup.e at 25.degree. C., this material had a dielectric constant of 95 an 
a volume resistivity of 1.3 .times. 10.sup.9 ohmcm at 24.degree. C. and 1 
volts; exhaustive hydrolysis of epoxide by reaction of component A with B 
was indicated by NMR spectroscopy 
The flexible, hard, transparent films of the invention possessed excellent 
antifogging and antistatic properties and readily exchanged cationic 
material. Evolution of heat (exotherm) was usually noted when 
epoxy-containing compounds such as gamma-glycidoxypropyltrimethoxysilane 
and sulfonic acids were combined in these coating formulations and 
external heat was not required. It was found that if this exotherm was 
moderated by cooling with an ice bath, for example, and this coating 
formulation was then cured, the resultant films were less conductive and 
exhibited higher abrasion resistance than those films prepared from 
coating formulations whose exotherms were not moderated. 
The data of Table I show: 
(1) a range of silanol-sulfonic acid concentrations are useful in producing 
conductive films; 
(2) increased amounts of sulfonate in the films allow for increase in 
conductivity and for an increase in ion-exchange capacity; 
(3) the static decay performance of the films is not affected by storage 
under dehydrating conditions; and 
(4) exhaustive hydrolysis is necessary to generate films of low surface 
resistivity and may be promoted by heating if there is no spontaneous 
exotherm upon combination of A and B (see sample 1, footnote "d"). 
EXAMPLE 2 
The conductivities of polymeric films having varying amounts of 
hydroxyorganosilane monomer components were compared. 
The exhaustive hydrolysis product of gamma-glycidoxypropyltrimethoxysilane 
[gamma-(beta,gamma-dihydroxypropoxy)-propylsilanetriol] was prepared by 
one day room temperature stirring of a mixture of 60 ml of 1 percent 
aqueous sulfuric acid with 40 g of gamma-glycidoxypropyltrimethoxysilane 
(A-187, Union Carbide, New York, NY). Conventional organic functional 
group tests for epoxide and diol groups were consistent with the expected 
structures. The pH of this solution was raised to about 6 by the addition 
of calcium carbonate, followed by filtration through diatomaceous earth. 
The resulting clear filtrate was 22 percent diol (solids) and was used in 
samples 6-10 of TABLE II below. 
Coating formulations were prepared according to the formulations in TABLE 
II by adding to the requisite amount of dihydroxyorganosilanol solution 
prepared above, the corresponding amount of A (EXAMPLE 1), water, a few 
drops of a 10 percent solution of Triton X-100, and a few drops of 
hexafluoroantimonic acid hexahydrate as the acid catalyst. To insure that 
there was no appreciable hydrolysis of the epoxy function of the epoxy 
functional silane to its diol derivative, the acid catalyst was added 
immediately prior to coating the resultant formulation onto polyvinylidene 
chloride-primed polyethylene terephthalate. The coating was cured at 
90.degree. for 30 minutes. 
TABLE II 
______________________________________ 
Resistivity of Films from Diol- and Epoxy-Containing Monomers 
Sam- Diol Water Approximate 
Surface Resistivity 
ple wt. A added mole ratio 
of polymeric film 
no. (g) wt. (g) (g) diol/epoxy 
(ohms/square).sup.a 
______________________________________ 
6 4.5 0 0 1.6 .times. 10.sup.9.sup. 
7 4 0.18 0.32 6.8 5 .times. 10.sup.9 
8 3 0.57 1 1.8 6 .times. 10.sup.10 
9 2 0.84 1.7 0.7 5 .times. 10.sup.12 
10.sup.b 
0 1.5 3 0 greater than 10.sup.13 
______________________________________ 
.sup.a resistivity measured at 32 percent relative humidity (R.H.) 
.sup.b control 
The data of TABLE II show that if the epoxide function of 
glycidoxypropyltrimethoxysilane is first converted to the diol derivative 
followed by silane polymerization during curing, the resultant polymeric 
film exhibits good conductivity (sample 6). By contrast, if the epoxide 
function of this monomer is not allowed to form the diol, the cured film 
(control) shows poor conductivity (sample 10). These experiments clearly 
illustrate that hydroxyalkyl functionality is important in imparting good 
conductivity to the cured film. Furthermore, the desired conductivity of 
the conductive polymeric film can be dictated by choosing the proper ratio 
of diol derivative to epoxide containing silane (samples 6-9). In sum, 
increasing the concentration of hydroxyorganosilane monomer within the 
conductive polymeric film results in an increase in the conductivity of 
that film. 
EXAMPLE 3 
The preparation and use of gamma-hydroxypropylsilanetriol as a conductive 
polymeric film is shown. 
Sodium methoxide solution was prepared by adding 2.3 g of metallic sodium 
to 100 ml of anhydrous methanol. To the room temperature solution was 
added 22.2 g of gamma-acetoxypropyltrimethoxysilane and the resultant 
mixture was stirred at room temperature for 22 hours and then concentrated 
to a small volume under reduced pressure. To the residue was added 50 ml 
of water and the product was stirred for three hours at room temperature. 
This solution was neutralized by ion exchange by passage through a column 
of Amberlite IR 120 (in the acid form) to afford a solution of 
gamma-hydroxypropolysilanetriol at about 7% solids, whose volume was 
reduced (by concentration under reduced pressure using a rotary vacuum 
evaporator) to afford a solution which was about 21% solids. This 
solution, 5 g, was combined with Triton X-100 and hexafluoroantimonic acid 
hexahydrate as described in EXAMPLE 1. The resultant formulation was 
coated (RDS Bar Coater No. 24) onto polyvinylidene chloride-primed 
polyethylene terephthalate substrate and cured at 90.degree. C. for 30 
minutes . The cured polymeric film had a surface resistivity of 
1.5.times.10.sup.10 ohms/square at 22 percent relative humidity. Note that 
films prepared from gamma-acetoxypropyltrimethoxysilane without prior 
exhaustive hydrolysis of the acetoxy function are not conductive. 
EXAMPLE 4 
This example is a study of the correlation between pH and surface 
resistivity. 
The acidic solution of the exhaustive hydrolysis product of 
gamma-glycidoxypropyltrimethoxysilane (described in EXAMPLE 2 above) was 
titrated to pH values between 1.5 and 11.0 with barium hydroxide. These 
diol solutions were coated, cured and the surface resistivities of the 
resulting films were measured at 25 percent relative humidity. Results 
showed that film derived from diol solutions of pH 5.0 and above had 
surface resistivities of about 10.sup.11 ohms/square, while films derived 
from diol solutions of lower pH exhibited better conductivities. For 
example, the cured film derived from the diol solution of pH 1.5 had a 
surface resistivity of 4.8.times.10.sup.8 ohms/square and the cured film 
derived from the diol solution of pH 3.0 had a surface resistivity of 
1.4.times.10.sup.10 ohms/square. 
EXAMPLE 5 
Samples were prepared using essentially the formulations of EXAMPLE 1, 
except that 0.1 percent by weight of a silica filler (Syloid.RTM.308, 
Davison Chemical Co.) was added to the formulations and coated at 
different thicknesses using RDS Bar Coater Nos. 3, 8, and 14. Resistivity 
data showed that the electrical behavior of filler and non-filler 
containing polymeric films of different thicknesses was essentially the 
same. 
EXAMPLE 6 
The static decay of portions of film sample 3 of EXAMPLE 1 above was 
measured and compared with that of a commercial film. The static decay 
time (in seconds) of the sample was determined by charging the sample to 
5000 volts and measuring the time in seconds to decay to 500 volts and the 
results are tabulated in Table III. 
TABLE III 
______________________________________ 
Static Discharge Properties of Films 
Percent relative 
Static decay (in sec.).sup.a of stored samples 
Sample 
humidity of Initial 1 2 3 1 
no. films at 24.degree. C. 
testing week weeks weeks month 
______________________________________ 
11.sup.b 
7 0.17 0.32 0.75 0.86 0.86 
12.sup.c 
7 0.04 0.04 0.03 0.03 0.04 
13.sup.b 
20 0.13 0.23 1.1 3.2 5.7 
14.sup.c 
20 0.04 0.04 0.04 0.04 0.04 
15.sup.b 
50 0.14 0.22 2.0 16.7 25.2 
16.sup.c 
50 0.04 0.04 0.04 0.05 0.05 
17.sup.b 
75 0.11 0.17 1.54 6.0 11.9 
18.sup.c 
75 0.05 0.04 0.04 0.05 0.04 
19.sup.b 
Saturated 0.18 0.85 12.3 43.0 19.7 
20.sup.c 
Saturated 0.05 0.04 0.05 0.05 0.06 
______________________________________ 
.sup.a measured at 7% relative humidity, 24.degree. C. 
.sup.b control is Richmond film RCAS 1200 (Richmond Corporation, Redlands 
CA) 
.sup.c present invention film 
The data of TABLE III show that the conductive polymeric films of the 
present invention maintain their static decay properties and outperform a 
state of the art material. 
EXAMPLE 7 
Polymeric films were prepared identical to sample 2 of EXAMPLE 1, except 
that catalytic amounts (i.e., 2 to 3 weight percent of the silane) of the 
following acid catalysts were included: 
(1) hexafluoroantimonic acid hexahydrate 
(2) (CF.sub.3 SO.sub.2).sub.2 CHC.sub.6 H.sub.5 (disclosed in U.S. Pat. No. 
4,049,861) 
(3) trifluoromethanesulfonic acid The formulations were evaluated, after 
heat curing, as to surface resistivity and static decay by methods 
described above. The data show that the conductive polymeric films of the 
present invention have excellent surface conductivity and exhibit 
excellent static decay independent of the acid catalyst used in the films' 
construction. 
A photoactivatable initiator was used as an acid catalyst in a film 
prepared as in EXAMPLE 2 but having 1 percent by weight of 
triphenylsulfonium hexafluoroantimonate (U.S. Pat. No. 4,173,476) added to 
2 g of 22 percent (in water) hydrolyzed diol, 
gamma-(beta,gamma-dihydroxypropoxy)propylsilanetriol, containing 1 ml of 
isopropyl alcohol with 0.5 percent Triton X-100. This formulation was 
coated (RDS Bar Coater No. 14) onto polyvinylidene chloride-primed 
polyethylene terephthalate substrate and cured for one minute with a 
medium-pressure Hanovia ultraviolet lamp (Hanovia Lamp Division, 
Canrad-Hanovia, Inc., Newark, NJ). The resulting tack-free composite 
exhibited a surface resistivity of 5.8.times.10.sup.8 ohms/square at 58 
percent relative humidity and 1.5.times.10.sup.10 ohms/square at 7 percent 
relative humidity. This tack-free composite could be thermally cured 
thereafter to improve film hardness if desired. 
EXAMPLE 8 
Different silanol-sulfonic acids were used with A (see EXAMPLE 1) to give 
coatings according to the following procedure. 
A coating formulation was prepared according to the method of EXAMPLE 1 by 
mixing 3 g of A with 1 g of selected silanol-sulfonic acid as indicated in 
Table VI. The silane was used at 67 percent solids and the silanolsulfonic 
acid was used at 23 percent solids. After the exotherm had subsided, 
Triton X-100 and hexafluoroantimonic acid hexahydrate were added as in 
EXAMPLE 1 and the well-mixed coating formulation was coated with an RDS 
Bar Coater No. 14 onto primed polyethylene terephthalate substrate. The 
coating was cured to a hard polymeric conductive film by heating in an 
oven at 90.degree. C. for 30 minutes. Resistivities of the resultant films 
(samples 21 to 26) were measured at 9 percent relative humidity and the 
results are summarized in Table IV. 
TABLE IV 
__________________________________________________________________________ 
Resistivity of Films Using Various Silanol-Sulfonic Acids 
Film 
Sample surface resistivity 
no. Silane chemical structure 
Source.sup.a 
(ohms/square) 
__________________________________________________________________________ 
21 
##STR9## Ex. 1, 2 
3.0 .times. 10.sup.10 
22 
##STR10## Ex. 7 
2.6 .times. 10.sup.9 
23 
##STR11## Ex. 9 
2.4 .times. 10.sup.11 
24 HO.sub.3 SCH.sub.2 CH.sub.2 Si(OH).sub.3 
Ex. 3 
7.5 .times. 10.sup.9 
25 HO.sub.3 SCH.sub.2 CH.sub.2 CH.sub.2 Si(OH).sub.3 
Ex. 5 
4.7 .times. 10.sup.10 
26 HO.sub.3 SCH.sub.2 CH.sub.2 CH.sub.2 SCH.sub.2 CH.sub.2 CH.sub.2 
Si(OH).sub.3 Ex. 6 
8.0 .times. 10.sup.12 
__________________________________________________________________________ 
.sup.a example numbers in this column refer to that example in the U. S. 
Pat. No. 4,235,638 
.sup.b represents a control; prepared as described in Example 1 
The data of TABLE IV show that a variety of silanol-sulfonic acids may be 
used to prepare conductive films of the present invention. 
EXAMPLE 9 
Films prepared as in EXAMPLE 1 but having 3 g of A reacted with organic 
sulfonic acids (listed below) were evaluated as to resistivity, then 
rinsed with about 100 ml of deionized water, which was applied as a fine 
stream onto the film's surface, air dried, and again evaluated as to 
resistivity. The results indicate that coating and curing of formulations 
containing organic sulfonic acids as additives produced polymeric 
conductive films of acceptable resistivity. However, when these films were 
contacted with water, the films exhibited lower conductivity. These 
noncopolymerizable organic sulfonic acid additives exhibited solvent 
sensitivity due to their water leachability from, and mobility in, the 
resultant polymeric films. In contrast, the coreacted silanol-sulfonic 
acid-containing films exhibit excellent solvent resistance. 
The organic sulfonic acids used were 
##STR12## 
EXAMPLE 10 
Samples 27 to 40 illustrate the use of different silanol-sulfonate salts as 
components in formulations to give polymeric conductive films. 
A coating formulation was prepared according to the method of EXAMPLE 1 by 
mixing 3 g of A with 1 g of B. After the resultant exotherm had subsided, 
the acidic solution (pH about 1) was diluted with 2 ml of water (samples 
33 to 39) or not diluted (samples 27 to 32, and 40) and titrated with a 
base whose cation is indicated in Table V. In these examples, a strong 
base was used and the salt-forming titration was stopped when the pH was 
between 4.0 and 4.5. To 4 g of the resulting solution was added 2 ml of 
methanol (samples 27 to 32, and 40) or no methanol was added (samples 33 
to 39), 3 drops of 10 percent Triton X-100 in water, and 3 drops of 
hexafluoroantimonic acid hexahydrate. The coating formulation was coated 
onto polyvinylidene chloride-primed polyethylene terephthalate substrate 
using an RDS Bar Coater No. 14, and the coating was cured in an oven at 
90.degree. for 30 minutes. The results are shown in TABLE V. 
TABLE V 
______________________________________ 
Resistivity of Films Containing Various Silanol-Sulfonate Salts 
Surface Resistivity 
Sample (ohms/square) 
no. Cation.sup.a pH.sup.b 
9% R.H. 58% R.H. 
______________________________________ 
27 (HOCH.sub.2 CH.sub.2).sub.4 N.sup.+a1 
5.3 1.4 .times. 10.sup.10 
7.8 .times. 10.sup.7 
28 (C.sub.6 H.sub.5 CH.sub.2)(CH.sub.3).sub.3 N.sup.+a2 
5.3 6.6 .times. 10.sup.8 
1.0 .times. 10.sup.8 
29 (CH.sub.3).sub.4 N.sup.+a3 
5.0 2.5 .times. 10.sup.10 
1.2 .times. 10.sup.8 
30 (n-C.sub.4 H.sub.9).sub.4 N.sup.+a4 
5.3 1.8 .times. 10.sup.10 
2.0 .times. 10.sup.8 
31 Na.sup.+a5 5.3 7.0 .times. 10.sup.9 
8.6 .times. 10.sup.7 
32 Ba.sup.+a6 5.0 1.2 .times. 10.sup.11 
7.6 .times. 10.sup.8 
33 Mg.sup.++a7 5.0 4.1 .times. 10.sup.10 
2.8 .times. 10.sup.8c 
34 Zn.sup.++a8 5.0 5.0 .times. 10.sup.10 
4.3 .times. 10.sup.8c 
35 Ni.sup.++a9 5.5 1.0 .times. 10.sup.11 
8.8 .times. 10.sup.8c 
36 Co.sup.++a10 4.0 4.4 .times. 10.sup.10 
4.8 .times. 10.sup.8c 
37 Cu.sup.++a11 4.5 3.0 .times. 10.sup.10 
2.8 .times. 10.sup.8c 
38 Pb.sup.++a12 4.0 8.4 .times. 10.sup.9 
1.0 .times. 10.sup.8c 
39 Cd.sup.++a13 4.3 2.8 .times. 10.sup.10 
2.4 .times. 10.sup.8c 
.sup. 40.sup.d 
H.sup.+ 1.0 1.3 .times. 10.sup.9 
4.7 .times. 10.sup.8 
______________________________________ 
.sup.a acidic solution titrated with the following bases: 
.sup.a1 90 percent (HOCH.sub.2 CH.sub.2).sub.4 N.sup.+ OH.sup.- in water 
(RSA Corp., Ardsley, NY) 
.sup.a2 40 percent (C.sub.6 H.sub.5 CH.sub.2)(CH.sub.3).sub.3 N.sup.+ 
OH.sup.- in methanol (Aldrich Chemical Co., Milwaukee, WI) 
.sup.a3 20 percent (CH.sub.3).sub.4 N.sup.+ OH.sup.- in methanol (Aldric 
Chemical Co.) 
.sup.a4 25 percent (nC.sub.4 H.sub.9).sub.4 N.sup.+ OH.sup.- in methanol 
(Eastman, Rochester, NY) 
.sup.a5 25 percent sodium hydroxide in water 
.sup.a6 saturated barium hydroxide in water 
.sup.a7 solid magnesium hydroxide 
.sup.a8 solid zinc carbonate 
.sup.a9 solid nickel carbonate 
.sup.a10 solid cobalt carbonate 
.sup.a11 solid copper carbonate 
.sup.a12 solid lead carbonate 
.sup.a13 solid cadmium hydroxide 
.sup.b pH measured after titration and prior to addition of surfactant an 
acid catalyst 
.sup.c measured at 53 percent relative humidity 
.sup.d control 
The data show that a variety of silanol-sulfonate salts may be used to 
produce conductive polymeric films. 
EXAMPLE 11 
An organosilane-phosphonic acid was prepared according to the procedure of 
G. H. Barnes and M. P. David, J. Org. Chem., 25, 1191 (1960). Hydrolysis 
of 1 g of dimethyl triethoxysilylethylphosphonate in 5 g of refluxing 
concentrated HCl for 23 hours affords, after evaporation of solvent, the 
solid siloxane phosphonic acid. 
A coating solution was prepared by combining 1.0 g of a 20% aqueous 
solution of the organosilane-phosphonic acid with 2.0 g of a 10% aqueous 
solution of [gamma-(beta, gamma-dihydroxypropoxy)-propylsilanetriol] of 
Example 2. 
A cured film on polyvinylidene chloride-primed polyethylene terephthalate 
was prepared according to the procedure of EXAMPLE 1. 
The film was flexible, hard, transparent, antifogging, and 
cation-exchangeable. Surface resistivity of the cured film was 
3.8.times.10.sup.10 ohms/square at 12% relative humidity. 
The results show that silane phosphonates are also useful in the practice 
of this invention. 
EXAMPLE 12 
Cured films coated on polyvinylidene chloride-primed polyethylene 
terephthalate, prepared as described in EXAMPLE 4, were subjected to 
cation exchange (cations used were Na.sup.+, Ag.sup.+, Mg.sup.+2, 
Cu.sup.+2, Mn.sup.+2, Fe.sup.+3, Cr.sup.+3, methylene blue cation, C.sub.6 
H.sub.5 CH.sub.2 (C.sub.6 H.sub.5).sub.3 P.sup.+, C.sub.6 H.sub.5 CH.sub.2 
(C.sub.2 H.sub.5).sub.3 N.sup.+, (n--C.sub.4 H.sub.9).sub.4 N.sup.+, and 
(NH.sub.2).sub.2 C.dbd.NH.sub.2.sup.+. Cations used were exchanged into 
the silanol-sulfonic acid-containing films and the resulting films showed 
excellent conductivity. 
EXAMPLE 13 
A pressure sensitive, conductive film-containing tape which can be 
dispensed according to length to overcome a problem of charge generation, 
was prepared. 
The coating formulation of sample 2, TABLE I above, was prepared according 
to the method of EXAMPLE 1. This formulation was coated onto 
polyvinylidene chloride-primed polyethylene terephthalate substrate and 
the coating was cured to yield a conductive polymeric film. The top, 
conductive surface of this film was overcoated (using a RDS Bar Coater No. 
3) with a release coating composition such as a low adhesion backsize. 
The pressure sensitive adhesive (such as a water-based acrylate) was next 
applied (using RDS Bar Coater No. 8) to the remaining, uncoated, suitably 
primed surface of the substrate. The resultant conductive composite tape 
may be affixed, e.g., by applying finger pressure, to a non-conducting 
surface to provide protection against static charge generation. The 
resistivity of this tape was determined to be about 4.5.times.10.sup.10 
ohms/square at 19 percent relative humidity. A control film of the release 
coating, prepared using RDS Bar Coater No. 3 and cured at 90.degree. for 
five minutes, had a resistivity of greater than 10.sup.13 ohms/square at 
19 percent relative humidity, and a control film of the pressure sensitive 
adhesive, prepared using RDS Bar Coater No. 8 and cured at 90.degree. for 
ten minutes, had a resistivity of greater than 10.sup.13 ohms/square at 19 
percent relative humidity. The polyester substrate also had a resistivity 
of greater than 10.sup.13 ohms/square at this relative humidity. 
EXAMPLE 14 
A substrate-supported conductive film overcoated with a pressure sensitive 
adhesive was prepared. 
The substrate-supported conductive polymeric film was prepared exactly as 
described in the EXAMPLE 12. This composite was overcoated with a pressure 
sensitive adhesive (i.e., a water-based acrylate) (using RDS Bar Coater 
No. 8) to give a conductive composite. The surface resistivity, measured 
on the adhesive side, was 4.8.times.10.sup.9 ohms/square at 58 percent 
relative humidity and 2.2.times.10.sup.10 ohms/square at 9 percent 
relative humidity. 
EXAMPLE 15 
Samples 41 to 50 demonstrate the capability of constructing composite 
polymeric films having a substrate, a conductive polymeric film, and an 
overcoating of an abrasion resistant polymeric film wherein the 
thicknesses of the films of the composite may be the same or different. 
A base coating formulation, that on curing yielded a conductive polymeric 
film, was prepared as detailed in EXAMPLE 1, sample 1. The proportions of 
A to B in the samples were as specified in TABLE VI. Hydrolyzate solution 
A (see EXAMPLE 1) was a 67 percent solution, and silanol-sulfonic acid 
solution B (see EXAMPLE 1) was a 23 percent solution. 
An overcoating formulation that on curing yielded an abrasion resistant 
polymeric film (ARC, see footnote e, Table VI) was prepared according to 
the method of EXAMPLE 1 by adding to 6 g of A 4 ml of methanol, a few 
drops of hexafluoroantimonic acid hexahydrate as the acid catalyst, and a 
few drops of a 10 percent ethyl acetate solution of a fluorochemical 
acrylate copolymer (see Ex. 1, U.S. Pat. No. 3,787,351) as the leveling 
agent. 
A polyvinylidene chloride-primed polyethylene terephthalate substrate was 
coated with the above base coating formulation. The coated substrate was 
cured at 90.degree. for 30 minutes, and after equilibration of the film 
under ambient conditions for the appropriate period of time, the film was 
overcoated with the overcoating formulation designated in Table VI with 
RDS Bar Coater No. 14, unless otherwise specified. The overcoated material 
was then cured at 90.degree. for 30 minutes. Both the conductivity and the 
haze measurements on these composite films were measured and recorded in 
Table VI. 
TABLE VI 
__________________________________________________________________________ 
Resistivity and Abrasion Resistance of Composite Polymeric Films 
Coating formulation 
Composite polymeric film 
Base Over- 
Surface Abrasion resistance 
Sample 
coating.sup.a 
coating.sup.b 
Resistivity 
Percent 
(percent haze) 
no. (A:B) 
(A:B) 
(ohms/square) 
R.H. Before 
After.sup.c 
__________________________________________________________________________ 
.sup. 41.sup.e 
3:5 none 2.8 .times. 10.sup.7 
33 0.6 54.4 
.sup. 42.sup.e 
3:12 none 7.6 .times. 10.sup.7 
25 1.3 79.1 
.sup. 43.sup.e 
3:21 none 3.0 .times. 10.sup.7 
25 1.0 78.3 
44 3:5 3:1.sup.a 
2.9 .times. 10.sup.7 
28 0.4 20.9 
45 3:12 3:1.sup.a 
2.0 .times. 10.sup.7 
25 0.6 19.9 
46 3:21 3:1.sup.a 
2.0 .times. 10.sup.7 
25 0.9 20.2 
.sup. 47.sup.e 
None ARC.sup.d 
greater than 10.sup.13 
33 0.4 9.6 
48 3:5 ARC 3.0 .times. 10.sup.8 
33 0.4 5.8 
49 3:15 ARC .sup. 2.5 .times. 10.sup.10 
25 0.3 4.0 
.sup. 2.0 .times. 10.sup.11 
9 
50 3:21 ARC .sup. 1.6 .times. 10.sup.10 
25 0.5 5.2 
.sup. 2.0 .times. 10.sup.11 
9 
__________________________________________________________________________ 
.sup.a A:B represents ratio of A to B as prepared in EXAMPLE 1 
.sup.b RDS Bar Coater No. 3 used for overcoating in samples 47 and 48 
.sup.c percent haze is measured on a Gardner hazemeter after 1000 cubic 
centimeters of falling sand. Low haze value indicated higher abrasion 
resistance 
.sup.d Preparation and curing of ARC (abrasion resistant polymeric film) 
is described in text for samples 47 to 50 
.sup.e control 
EXAMPLE 16 
A composite composition having a gelatin-containing overcoating composition 
was prepared. 
A polyvinylidene chloride-primed polyethylene terephthalate substrate was 
coated with a composition prepared as described in sample 2 of EXAMPLE 1 
and cured under the described conditions. The resultant conductive 
polymeric film was overcoated with a 5 percent aqueous gelatin solution 
using RDS Bar Coater No. 36. The overcoating was cured by allowing it to 
stand for one day at room temperature. The resulting composite had a 
surface resistivity of 4.0.times.10.sup.8 ohms/square at 61 percent 
relative humidity, and 8.8.times.10.sup.10 ohms/square at 9 percent 
relative humidity, while a control sample prepared by coating the gelatin 
layer on the above uncoated substrate had a surface resistivity of greater 
than 10.sup.13 ohms/square at 53 percent relative humidity. 
EXAMPLE 17 
Composite compositions having a fabric substrate were prepared. Samples of 
two commercially available fabrics (e.g., woven acrylic and nylon taffeta) 
were immersed in a vessel containing 1 percent (solids) of mixtures of A 
and B (i.e., 3:1 and 3:4 ratios, see EXAMPLE 1) prepared according to the 
directions of EXAMPLE 1. These coated fabric samples were then squeezed 
between two rollers to remove excess coating composition and cured by 
heating at 90.degree. for ten minutes. Static decay tests of the treated 
fabrics were then performed, as described in EXAMPLE 1, at 22.degree. and 
50 percent relative humidity. The results indicated that treated fabrics 
"bled off" electrostatic charges since they had a static decay value of 
fractions of a second, whereas, the control samples of untreated fabric 
had static decay values greater than one second. 
EXAMPLE 18 
Use of silanol-sulfonate-containing polymeric films of this invention as 
antifogging films was demonstrated. 
A coating formulation prepared according to the directions for sample 1 of 
EXAMPLE 1 was coated onto polyethylene terephthalate using RDS Bar Coater 
No. 22 and cured at 90.degree. for 30 minutes. The remaining uncoated side 
of the substrate was similarly coated with the same formulation which was 
then cured as above. The composite film just prepared and a control of 
polyethylene terephthalate film were placed in a freezer at -15.degree. C. 
for ten minutes. Upon removal of the films from the freezer into a room at 
24.degree. C. and 58 percent relative humidity, the composite film did not 
fog, while the control film did fog. Similarly, when breathed upon, the 
composite film did not fog, while the control fogged. 
Various modifications and alterations of this invention will become 
apparent to those skilled in the art without departing from the scope and 
spirit of this invention, and it should be understood that this invention 
is not to be unduly limited to the illustrative embodiment set forth 
herein.