Sheet or web carrying an antistatic layer

A sheet or web comprising a substrate which is composed of or coated with a hydrophobic resin and carries an antistatic layer, characterized in that the antistatic layer consists essentially of a blockcopolyetherester of dibasic carboxylic acid(s) esterified with ethylene glycol and with a polyoxyethylene glycol having an average molecular weight in the range 1,000 to 10,000, at least 20% by weight of such blockcopolyetherester being constituted by polyoxyethylene-ester chain parts.

DESCRIPTION 
The present invention relates to a sheet or web comprising a substrate 
which is composed of or coated with a hydrophobic resin and carries an 
antistatic layer. 
The invention is particularly but not exclusively concerned with recording 
materials wherein such a sheet or web carries a recording layer, e.g. a 
light-sensitive silver halide layer. 
It is known that sheets and webs of low conductivity, e.g. sheets and webs 
of resin or resin-coated paper, readily become electrostatically charged 
by friction with dielectric materials and/or contact with 
electrostatically chargeable transport means, e.g. rollers. The charging 
occurs particularly easily in a relatively dry atmospheric environment. 
Sheets and webs of hydrophobic resin are commonly used as supporting 
substrates of recording materials. Such substrates are subjected to 
frictional contact with other elements during the manufacture of the 
recording materials, e.g. during a coating or cutting stage, and during 
use, e.g. during the recording of information or (in the case of silver 
halide photographic materials) during image-processing or final image 
inspection or projection. Especially in the reeling-up or unreeling of dry 
photographic film in a camera or projector high friction may build up, 
resulting in electrostatic charges that may attract dust or cause 
sparking. In unprocessed photographic silver halide emulsion materials 
sparking causes developable fog and degrades the image quality. 
In order to reduce electrostatic charging of sheets or webs comprising a 
hydrophobic resin layer or support, e.g. a polyethylene layer on paper or 
a cellulosetriacetate or polyethylene terephthalate resin support, it is 
known to apply coatings which are formed of or incorporate ionic 
compounds. In some light-sensitive materials, such ionic compounds are 
incorporated in a silver halide emulsion layer. In order to avoid 
diffusion of ionic compounds out of the silver halide emulsion during its 
different wet processing treatments, preference has been given to 
antistatic high molecular weight polymer compounds having ionic groups at 
frequent intervals in the polymer chain (ref. Photographic Emulsion 
Chemistry, by G. F. Duffin,--The Focal Press--London and New York 
(1966)--Focal Press Limited, p. 168. 
Ionic polymers containing carboxylate groups have good antistatic 
properties in the pH range above 6, but fail because of their low 
dissociation degree at lower pH values. 
Ionic polymers containing sulphonic acid grops or a salt form thereof 
interact with amino groups of proteinaceous colloids at pH values above 
4.5 and, if incorporated into coating solutions containing such colloids, 
cause a considerable increase in viscosity of the coating solutions and 
even flocculation thereof. 
Ionic polymers containing protonated or quaternized amino groups, although 
being good antistatic agents are often useless in photographic silver 
halide emulsion materials because of their fogging activity. This can be 
counteracted by using substantial amounts of anti-fogging agents, but only 
at the expense of photographic sensitivity. Moreover, such ionic polymers 
are not compatible with the use of anionic wetting agents as often used in 
the coating composition of such materials because the cationic part of 
said polymers interact with the wetting agents and form large complex 
compounds having little or no antistatic effect. 
It has been established also that the dissociation of ionic type antistatic 
polymers is strongly dependent on the water content of the elements 
wherein they are incorporated. 
It is known from Acta Polymerica 35 (1984) Nr. 4, p. 309-315 to use 
blockcopolyetherester compounds for providing a permanent antistatic 
character to polyacrylonitrile fibers. For that purpose the 
polyacrylonitrile is dissolved together with the blockcopolyetherester in 
a mixture of dimethyl formamide and water and co-extruded in a non-solvent 
coagulation liquid to form antistatic fibers. The most suitable of such 
antistatic compounds for that purpose are said to be those containing 
80-85% of esterified polyethyleneglycol. The preparation of the 
blockcopolyetherester proceeds by condensation in the melt of an 
oligomer-free bis-(beta-hydroxyethyl)-terephthalate in admixture with a 
polyoxyethylene glycol of a molecular weight e.g. in the range of 1,000 to 
10,000. Hereby through re-esterification and polycondensation structural 
blocks of repeating units of terephthalic acid esterified with ethylene 
glycol and with polyoxyethylene glycol are obtained. 
It has been found that certain blockcopolyetheresters afford particular 
advantages if used to form or as ingredients of antistatic layers in webs 
or sheets comprising a substrate which is formed of or coated with a 
hydrophobic resin. Unlike the ionic compounds hitherto incorporated in 
such webs or sheets of antistatic purposes, suitably selected 
blockcopolyetheresters can be used to form antistatic layers whose surface 
resistivity is not substantially affected by exposure to acid or alkaline 
media. Moreover such layers can be provided in photographic sheets or webs 
incorporating silver halide emulsion layers without adversely affecting 
the photographic sensitivity. 
According to the present invention, there is provided a sheet or web 
comprising a substrate which is composed of or coated with a hydrophobic 
resin and carries an antistatic layer, characterised in that the 
antistatic layer consists essentially of a blockcopolyetherester of 
dibasic carboxylic acid(s) esterified with ethylene glycol and with a 
polyoxyethylene glycol having an average molecular weight in the range 
1,000 to 10,000, at least 20% by weight of such blockcopolyetherester 
being constituted by polyoxyethylene-ester chain parts. 
The surface resistivity of antistatic layers as used according to the 
invention depends on the proportion of oxyethylene groups therein. By 
increasing this proportion the surface resistivity of the layer can be 
reduced. However, an increase in the proportion of oxyethylene groups 
tends to make the layer less capable of good adherence to a hydrophobic 
substrate. Therefore in the preparation of a blockcopolymer for use 
according to the invention in the production of a web or sheet, the 
proportion of hydrophilic groups should be controlled with regard not only 
to the required antistatic properties but also to the composition of the 
surface or surfaces to which the antistatic layer is to be applied. If the 
antistatic layer is to be applied directly to the hydrophobic resin 
substrate, i.e. without an intervening less hydrophobic subbing layer, the 
proportion of the blockcopolyetherester which is constituted by the 
polyoxyethylene-ester cannot be so high it could otherwise be. 
In preferred embodiments of the invention the polyoxyethylene-ester chain 
parts of the blockcopolymer constitute at least 75% by weight of such 
copolymer. 
An important use for the invention is in the manufacture of webs or sheets 
having a polyethylene terephthalate resin support. Preferred antistatic 
copolymers for direct application to a substrate of that resin are those 
prepared from terephthalic or isophthalic acid or mixtures thereof. 
Depending on the sequence length of the polyoxyethylene blocks and the 
content thereof watersoluble or waterinsoluble blockcopolyetheresters are 
obtained. 
The waterinsoluble products can be applied in dispersed form in hydrophilic 
colloid layers either by the use of dispersing agents and/or by 
incorporating in the structure of the blockcopolyetheresters small amounts 
of ionic groups, e.g. sulpho groups in salt form. For example, from 5 to 
10 mole % of the dibasic carboxylic acid or derivative thereof used in the 
production of the polyester part of the blockcopolyetherester can carry 
sulpho groups in salt form, preferably in the sodium salt form. For the 
improvement of dispersability in aqueous medium the blockcopolyetherester 
synthesis is preferably carried out with a minor amount of the 5-sulphonic 
acid sodium salt of isophthalic acid or its dimethyl ester derivative. 
For increasing the glass transition temperature (Tg) of the 
blockcopolyetherester and to reduce its stickiness, e.g. when a large 
amount of isophthalic acid is used as dicarboxylic acid, it is 
advantageous that a part of the ester groups, e.g. 0.05 to 1 mole % is 
derived from polycarboxylic acid(s) having at least three carboxylic acid 
groups. Preferably these acids are aromatic carboxylic acids containing at 
least four carboxylic acid groups not capable of forming intermolecularly 
an anhydride as described in U.S. Pat. No. 4,478,907. 
Particularly useful polycarboxylic acids for increasing the Tg-value in the 
blockcopolyetheresters used according to the present invention correspond 
to the following general formula including the corresponding esters: 
##STR1## 
wherein X represents a chemical bond or a bivalent atom or bivalent group 
of atoms e.g. oxygen, alkylene such as methylene, carbonyl, sulphonyl, 
--NHSO.sub.2 --, --NHCONH-- or a --NH--Q--Y--Q--NH--group wherein Q 
represents carbonyl or sulphonyl and Y represents a bivalent organic group 
e.g. a bivalent aliphatic or aromatic group. The carboxylic acid groups 
can be introduced on aromatic nuclei which are already linked by X, using 
techniques known in the art. Alternatively, the aromatic nuclei can be 
linked by the X group after the carboxylic acid or ester group 
substituents have been incorporated on such nuclei. The linking of such 
nuclei can be effected by a condensation reaction starting from 
5-amino-isophthalic acid or its corresponding lower alkyl ester e.g. 
dimethyl ester and the appropriate acid chloride to yield the bivalent X 
bond. 
Although ethylene glycol is preferably used as the sole monomeric diol in 
the preparation of the present blockcopolyetherester minor amounts (e.g. 
up to 5 mole %) of other monomeric diols may be used with the proviso that 
the product involved still posesses antistatic activity. Exemplary 
monomeric diols other than ethylene glycol and of which said minor amounts 
may be used are diethylene glycol, 1,3-propanediol, 1,4-butanediol, 
2-methyl-1,5-pentanediol, neopentylglycol, 1,4-cyclohexanedimethanol, 
norcamphanediols, p-xylene glycol and corresponding alkyl esters thereof. 
The blockcopolyetherester compounds used according to the present invention 
can be prepared by techniques known to those skilled in the art, e.g. a 
trans-esterification is carried out under nitrogen atmosphere and the 
polycondensation in the melt under reduced pressure. In the 
trans-esterification preferably the methyl ester of the dicarboxylic acids 
is used, whereas the polycondensation can start directly with the ethylene 
glycol monoester of said dicarboxylic acids. 
To illustrate the preparation of blockcopolyetheresters for use according 
to the present invention the following preparations are given. 
PREATION 1 
Blockcopolyetherester of terephthalic acid with 50 mole % of polyesterified 
ethylene glycol and 50 mole % of polyesterified polyoxyethylene glycol, 
wherein the polyoxyethylene-ester part represents 95.56% by weight of the 
blockcopolyetherester. 
In a reaction tube provided with a distillation condensor and a stirring 
system were introduced 40 g (0.01 mole) of polyoxyethylene glycol of 
average molecular weight (A.M.W.) 4,000, 5.08 g (0.02 mole) of 
bis-(beta-hydroxyethyl)-terephthalate (BHET) and 10 mg of 
Ti(OOC-phenylene-COOCH.sub.3).sub.4 as trans-esterification and 
polycondensation catalyst. 
The mixture was melted by heating to 280.degree. C. After obtaining a 
homogeneous melt the reaction mixture was kept for 3 h under reduced 
pressure (0.5 mm Hg) for distilling off ethylene glycol freed in the 
polycondensation. 
A pale brown coloured substance was obtained. The inherent viscosity of a 
0.5 wt% solution measured at 25.degree. C. in a mixture of phenol and 
orthochlorobenzene (60/40 by volume) was 1.2 dl/g. 
PREATION 2 
Blockcopolyetherester of terephthalic acid with 75 mole % of polyesterified 
ethylene glycol and 25 mole % of polyesterified polyoxyethylene glycol, 
wherein the polyoxyethylene-ester part represents 87.76% by weight of the 
blockcopolyetherester. 
The same procedure as applied in Preparation 1 was followed operating 
however with 10.16 g (0.04 mole) of BHET instead of 0.02 mole BHET. 
The inherent viscosity of a 0.5 wt% solution measured at 25.degree. C. in a 
mixture of phenol and orthochlorobenzene (60/40 by volume) was 1.25 dl/g. 
PREATION 3 
Blockcopolyetherester of terephthalic acid with 87.5 mole % of 
polyesterified ethylene glycol and 12.5 mole % of polyesterified 
polyoxyethylene glycol, wherein the polyoxyethylene-ester part represents 
75.45% by weight of the blockcopolyetherester. 
The same procedure as applied in Preparation 1 was followed operating 
however with 30 g (0.0075) of said polyoxyethylene glycol and 15.24 g 
(0.06 mole) of BHET. 
The inherent viscosity of a 0.5 wt% solution measured at 25.degree. C. in a 
mixture of phenol and orthochlorobenzene (60/40 by volume) was 1.22 dl/g. 
PREATION 4 
Blockcopolyetherester prepared from: 
53 mole % of terephthalic acid, 
40 mole % of isophthalic acid, 
7 mole % of 5-sulpho-isophthalic acid sodium salt, 
87.5 mole % of ethylene glycol, and 
12.5 mole % of polyoxyethylene glycol (A.M.W.: 4,000) 
The polyoxyethylene-ester part represents 75.19% by weight of the 
blockcopolyetherester. 
In a reaction tube provided with a distillation condenser and a stirring 
system were introduced: 
6.17 g (0.0318 mole) of dimethylterephthalate, 
4.66 g (0.024 mole) of dimethylisophthalate, 
1.24 g (0.0042 mole %) of 5-sulpho-isophthalic dimethylester sodium salt, 
8.18 g (0.132 mole) of ethylene glycol, and 
10 mg of Ti(OOC-phenylene-COOCH.sub.3).sub.4 
The mixture was heated for 2 h at 196.degree. C. under nitrogen atmosphere. 
During the trans-esterification reaction methanol was distilled off. 
Thereupon 30 g (0.0075 mole) of polyoxyethylene glycol (A.M.W.: 4,000) was 
added. The temperature was raised to 255.degree. C. in a period of 30 min 
and kept at that temperature for 15 min while maintaining the reaction 
mixture under N.sub.2 -atmosphere. The polycondensation was continued 
under reduced pressure lower than 0.5 mm Hg at 282.degree. C. for a period 
of 30 min to 3 h depending on the viscosity of polymer desired. 
A milky white to pale brown coloured substance was obtained. The inherent 
viscosity of a 0.5 wt% solution measured at 25.degree. C. in a mixture of 
phenol and orthochlorobenzene (60/40 by volume) was 1.06 dl/g. 
PREATION 5 
Blockcopolyetherester prepared from: 
60 mole % of terephthalic acid, 
40 mole % of isophthalic acid, 
98 mole % of ethylene glycol, and 
2 mole % of polyoxyethylene glycol (A.M.W.: 4,000) 
The polyoxyethylene-ester part represents 30.51% by weight of the 
blockcopolyetherester. 
In a reaction tube provided with a distillation condensor and a stirring 
system were introduced: 
18.1 g (0.096 mole) of dimethylterephthalate, 
12.43 g (0.064 mole) of dimethylisophthalate, 
21.81 g (0.352 mole) of ethylene glycol, and 
26.67 mg of Ti(OOC-phenylene-COOCH.sub.3).sub.4 
The mixture was heated for 2 h at 196.degree. C. under nitrogen atmosphere. 
During the re-esterification reaction methanol was distilled off. 
Thereupon 12.8 g (0.0032 mole) of polyoxyethylene glycol (A.M.W.: 4,000) 
was added. The temperature was raised to 255.degree. C. in a period of 30 
min and kept at that temperature for 15 min while maintaining the reaction 
mixture under N.sub.2 -atmosphere. The polycondensation was continued 
under reduced pressure lower than 0.5 mm Hg at 282.degree. C. for a period 
of 30 min to 3 h depending on the viscosity of polymer desired. 
PREATION 6 (compound for use in comparative Example 1) 
Blockcopolyetherester prepared from: 
53 mole % of terephthalic acid, 
40 mole % of isophthalic acid, 
7 mole % of 5-sulpho-isophthalic dimethylester sodium salt, 
100 mole % of ethylene glycol 
The blockcopolyetherester contains no polyoxyethylene-ester part. 
In a reaction tube provided with a distillation condensor and a stirring 
system were introduced: 
20.564 g (0.106 mole) of dimethylterephthalate, 
15.52 g (0.08 mole) of dimethylisophthalate, 
4.144 g (0.014 mole) of 5-sulpho-isophthalic dimethylester sodium salt, 
27.28 (0.44 mole) of ethylene glycol, and 
8.8 mg (4.times.10.sup.-5 mole) of zinc acetate dihydrate. 
The mixture was heated for 3 h at 196.degree. C. under nitrogen atmosphere. 
During the trans-esterification reaction methanol was distilled off. After 
3 h the temperature was raised to 255.degree. C. in a period of 30 min. 
and kept at that temperature for 15 min while maintaining the reaction 
mixture under nitrogen atmosphere. 
The polycondensation was continued under reduced pressure lower than 0.5 mm 
Hg at 255.degree. C. for a period 3 h. 
The inherent viscosity of 0.5 wt % solution measured at 25.degree. C. in a 
mixture of phenol and orthochlorobenzene (60/40 by volume) was 0.25 dl/g. 
For use according to the present invention the selected 
blockcopolyetherester compound(s) can be present as dispersed particulate 
material in a binder layer but is (are) preferably used to form in a 
continuous layer, either alone or in admixture with a hydrophilic colloid. 
According to one suitable procedure, the selected copolyetherester is (are) 
applied in layer-form by dissolving them in an organic solvent, e.g. a 
chlorinated hydrocarbon solvent such as methylene chloride and/or 
1,2-dichloro ethane, and evaporating the solvent after coating. 
According to an other procedure the copolymer is (are) applied from an 
aqueous dispersion, i.e. as a latex, which may be prepared by introducing 
the copolyetherester in powder form, optionally together with a dispersing 
agent, into water and raising the temperature above the glass transition 
temperature with stirring till a latex is obtained containing dispersed 
particles sizing up to 1,500 nm. 
As an example the copolyetherester of preparation 4 was dispersed in water 
to prepare a latex in the following manner: 
10 g of said blockcopolyetherester in the presence of 200 mg of 
2,4,6-(isobutyl)-1--(OCH.sub.2 --CH.sub.2).sub.7 --OSO.sub.3 Na benzene as 
dispersing agent were stirred at 95.degree. C. for 3 h in 150 ml of water. 
After cooling down to 20.degree. C. the fairly viscous oil was filtered 
and water was added up to a volume of 200 ml. The obtained latex particles 
had an average particle size of 1100 nm and were used lateron in the 
preparation of coating A4 of Example 1. 
By applying the above defined blockcopolyetherester compounds on an 
unsubbed polyethylene terephthalate support at a dry coating thickness of 
0.25 .mu.m a surface resistivity lower than 700.times.10.sup.10 Ohm per 
square can be obtained at a relative humidity of 30%. 
The surface resistivity of a coating antistatic layer is measured by a test 
proceeding as follows: 
After coating the resulting layer is dried and conditioned at a specific 
relative humidity. The surface resistivity measurement is performed by 
placing two conductive copper poles having a length of 1.0 cm parallel to 
each other at a distance of 1 cm forming a square inbetween and measuring 
the resistance built up between said electrodes with a precision 
Ohm-meter. 
The above defined blockcopolyetherester compounds can be used, e.g. in the 
production of layers on resin, paper or resin-coated paper supports. 
We have found by experiment that an antistatic layer containing one or more 
of the above defined blockcopolyetheresters provides antistatic properties 
not only when applied as an exterior layer but even when applied 
underneath a hydrophilic colloid layer, e.g. a layer containing gelatin. 
This is a very important and surprising discovery. The conductivity of the 
antistatic layer, attributable to the blockcopolyetherester, is sufficient 
to have a significant antistatic effect, given the small distance between 
induced surface charges and the antistatic layer (say 4 to 10 .mu.m), and 
the dielectric properties of the hydrophilic colloid layer. The intrinsic 
conductivity of the antistatic layer can be attributed to the mobility of 
the electron-transfering polyether chain parts in the 
blockcopolyetherester. 
As already stated, an important use for the invention is in the manufacture 
of recording materials comprising one or more recording layers on a 
hydrophobic resin or resin-coated support. The defined antistatic 
compounds are particularly beneficial for forming one or more antistatic 
layers in photographic materials containing at least one silver halide 
emulsion layer, and in image-receiving materials as used in conjunction 
therewith in the production of diffusion transfer images e.g. obtained by 
silver complex diffusion transfer or dye diffusion transfer. In a 
recording material, a said antistatic layer can be formed on top of the 
recording layer(s) provided the permeability and mechanical properties of 
such antistatic layer are satisfactory. However in the preferred 
embodiments of the invention, a layer containing at least one of the above 
defined blockcopolyetherester compounds is used as an under-layer (subbing 
layer) for a recording layer, e.g. a silver halide emulsion layer, in 
direct contact therewith. 
A web or sheet according to the invention can incorporate more than one 
antistatic layer, each incorporating one or more blockcopolyetheresters as 
herein defined. For example there may be one such antistatic layer on each 
side of the resin or resin-coated substrate. In that way a particularly 
high resistance to dust attraction and sparking can be achieved. 
In certain embodiments of the invention a silver halide photographic 
material is provided at the rear side of the hydrophobic resin or 
resin-coated support (the side opposite the light-sensitive layer(s)) with 
an antistatic layer containing one or more pigments in admixture with the 
blockcopolyetherester(s). Use can be made of pigments having 
anti-reflecting properties and/or antistatic properties. For example such 
said layer can be an anti-reflecting layer, also called antihalation 
layer, e.g. containing carbon black which confers the anti-reflecting 
properties and further increases the conductivity of the layer. Such an 
anti-reflecting layer can be removed after image-development by a solvent 
or solvent mixture. 
The present invention includes any polyester film material coated with an 
antistatic layer incorporating one or more of the blockcopolyetheresters. 
For photographic material a preferred polyester to the film forming 
support or substrate is polyethylene terephthalate. Although the Examples 
hereinafter set forth are directed to the coating of a polyethylene 
terephthalate film base, other polyester films may be used, e.g. 
polyesters resulting from the polycondensation of glycol or mixture of 
glycols, with terephthalic acid or mixtures of terephthalic acid with 
minor amounts of other dicarboxylic acids such as isophthalic acid, 
diphenic acid and sebacic acid. The polyester film may contain pigments or 
dyes and when used as base for X-ray film is, e.g., tinted blue. 
The blockcopolyetherester solution or aqueous dispersion may be applied to 
a said polyester film support either before or after it has been stretched 
or oriented. Preferably, however, the solution or dispersion is applied 
after biaxially stretching the film, e.g. in the temperature range of from 
80.degree. to 100.degree. C., the longitudinal stretch ratio being e.g. in 
the range of 2.5:1 to 4.0:1. The transverse stretching may be effected, 
e.g., at a ratio of 2.5:1 to 4.0:1. Thereupon the film is heat-set by 
heating in the range of 180.degree. C. to 220.degree. C. for 0.1 to 2 
minutes while it is restrained from shrinkage in both directions. 
If desired, adhesion-improving agents may be incorporated in the antistatic 
layer(s) in dissolved form, e.g. resorcinol, pyrocatechol, 
dihydroxytoluene, and chloral hydrate. Other ingredients, e.g. 
stretch-improving agents, sizing agents and friction lowering substances, 
e.g. waxes as described in U.S. Pat. No. 4,089,997 may be present in the 
antistatic layer. 
Other useful ingredients that may be added are, e.g., surface-active 
coating agents, colloidal silica and embossing agents also called spacing 
agents, i.e. particles for creating microscopic protrusions of less than 3 
.mu.m, for obtaining a thin air space between the subbed material and a 
material touching it, e.g. during transport of the film. Such embossing 
agents can be known matting agents, e.g. those described in the published 
European Patent Application 79/200053.1 filed Jan. 30, 1979 by 
Agfa-Gevaert N.V. 
An aqueous gelatin coating composition for forming a second layer on the 
subbing layer may in the case of photographic silver halide materials, 
contain plasticizers that are photographically inert and that have the 
property of making gelatinous layers stretchable without impairing their 
transparency as described, e.g. in the U.S. Pat. No. 3,988,157. In this 
respect are mentioned aliphatic polyhydroxy compounds such as glycerol, 
sorbitol, tri(beta-hydroxy-ethyl)-glycerol, 
1,1,1-tri(hydroxymethyl)-propane, 2-nitro-2-ethyl-1,3-propanediol, 
1,3-dichloro-2-propanol, 1,2,4-butanetriol, 
3-hydroxymethyl-2,4-dihydroxypentane, 1,2,6-hexanetriol, 
3-hydroxymethyl-4-hydroxyamyl alcohol, glycerol-aldehyde, glycerol 
dichlorohydrin, and mannitol. 
Equally suitable compounds are caprolactam, N,N'-dimethylurea, resorcinol, 
pyrocatechol, and dichlorodiethyl ether. Other suitable plasticizers are 
aliphatic carboxylic or sulphonic acids such as malonic acid, glutaric 
acid, adipic acid, azelaic acid, sebacic acid, mono- and di-chloro-acetic 
acid, 1,2,3-propene-tricarboxylic acid, trimellitic acid, acrylic acid, 
methacrylic acid, maleic acid, fumaric acid, itaconic acid, and 
2-sulpho-ethyl methacrylate; further aromatic acids such as phthalic acid, 
o-sulphobenzoic acid, o-nitrobenzoic acid, o-aminobenzoic acid, 
p-hydroxybenzoic acid, and salicylic acid. 
Moreover, polymeric plasticizers can be added to the gelatin coating 
composition, e.g. latices of copolymers of butadiene and a lwoer alkyl 
ester of acrylic or methacrylic acid e.g. a copolymer of butadiene and 
methyl methacrylate containing 20-80% by weight of methyl methacrylate. 
These latices are described in the United Kingdom Pat. No. 1,053,043. 
Hardening agents, spreading agents, antistatic or metal-complexing agents 
can also be added to the aqueous gelatin-containing coating composition. 
Suitable antistatic or metal complexing agents are the sodium salt of 
polystyrene sulphonic acid, alkali metal salts of co(styrene/maleic acid), 
inorganic salts such as sodium chloride, potassium chloride, and sodium 
orthosilicate, further citric acid, sulphosalicylic acid, 
2,5-disulphohydroquinone, the sodium salt of ethylenediamine tetraacetic 
acid, ethanol-amino-diacetic acid, the sodium salt of 
N(o-hydroxybenzyl)-amino-diacetic acid, the monosodium salt of vanadic 
acid, 3,5-disulphopyrocatechol, phosphono-acetic acid, 
ethylene-1,2-diphosphonic acid, butylene-1,4-disphosphonic acid, and 
ascorbic acid. 
Other possible ingredients for said layer are, e.g. surface-active coating 
aids, colloidal silica, and the already mentioned embossing agents. 
After the film has been heat-set a photographic material may be formed by 
applying a light-sensitive layer such as a gelatino silver halide emulsion 
layer optionally directly to the antistatic primer layer. Preferably, 
however an underlayer or subbing layer as aforesaid, of a hydrophilic 
colloid mainly containing gelatin, is provided. 
The photographic silver halide emulsion layer(s), when used, can be of any 
type of composition known to those skilled in the art. For examples of 
compositions, reference can be made, e.g. to Research Disclosure 17,643 of 
December 1978. 
Apart from light-sensitive hydrophilic colloid layers any 
non-light-sensitive hydrophilic colloid layer may be combined with an 
antistatic layer containing the desired blockcopolyetheresters, e.g. a 
gelatin layer containing developing nuclei for use in the silver complex 
diffusion transfer process or a hydrophilic colloid layer containing a 
mordanting agent for use in a dye diffusion transfer process as described 
e.g. in Angew. Chem. Int. Ed. Engl. 22, (1983) p. 191-209. 
By applying an antistatic layer containing the blockcopolyetheresters 
hereinbefore defined, problems caused by static charges can be avoided or 
substantially reduced. For example the formation of static charges by 
contact of a silver halide emulsion layer face with an emulsion layer face 
of an other silver halide emulsion material or the rear side of material 
or caused by friction with substances such as rubber and hydrophobic 
polymeric binder, e.g. the binder constituent of phosphor screens used as 
X-ray intensifying screens, can be markedly reduced by employing one or 
more antistatic layers in accordance with the present invention. The build 
up of static charges and subsequent dust attraction and/or sparking, e.g. 
during loading of films in cassettes, e.g. X-ray cassettes, or in cameras, 
or during the taking of a sequence of pictures as occurs in automatic 
cameras using X-rays films, can be avoided. 
Although the described blockcopolyetheresters are particularly useful in 
the forming of antistatic layers applied in silver halide emulsion 
materials they are likewise useful in reducing surface resistivity of 
diazo-type composition materials, vesicular-image forming materials, 
magnetic recording materials, electrophotographic or electrophotographic 
recording materials and mounting or drafting film. 
The following are (non-limiting) examples of materials according to the 
present invention and their manufacture. All percentages and ratios are by 
weight unless otherwise mentioned.

EXAMPLE 1 
Separate strips of bi-axially oriented unsubbed polyethylene terephthalate 
supports having a thickness of 0.1 mm were covered by a known coating 
method with a 5% by weight solution in a 50/50 vol% mixture of 
dichloroethane and methylene chloride of one of the blockcopolyetheresters 
of preparations 1, 2, 3, 4, 5, and 6. The coated layers were dried at 
45.degree. C. forming materials A1 to A6 each having an antistatic layer 
of a thickness of 4 .mu.m. 
Materials B1, B2 and B3 were prepared by coating strips of the materials 
A1, A2 and A3 respectively at the antistatic layer side with a hydrophilic 
colloid layer applied from the following mixture at 30 m.sup.2 /l: 
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10% aqueous gelatin solution 
80 ml 
33% aqueous dispersion of colloidal silica 
40 ml 
caprolactam 4 g 
hexanetriol 2 g 
10% aqueous solution of heptadecyl benzimidazole 
disulphonic acid disodium salt 
6 ml 
methanol 100 ml 
water 770 ml 
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Materials C1, C2 and C3 were prepared by coating strips of said materials 
B1, B2 and B3 on the hydrophilic colloid layer side with a gelatin-silver 
halide emulsion layer suited for X-ray image recording in combination with 
fluorescent intensifying screens. The emulsion layer having a thickness of 
3 .mu.m contained 2.2 g of gelatin per sq.m. and the weight ratio of 
gelatin to silver halide (expressed in equivalent amount of silver 
nitrate) was 0.4/1.0. The silver halide emulsion layer was coated with a 
protective layer (anti-stress layer) containing formaldehyde hardened 
gelatin and having a thickness of 1.1 .mu.m. 
The surface resistivity of said materials was measured at 30% relative 
humidity (R.H.) and the results thereof are listed in the following Table 
2. 
For comparison purposes the surface resistivity of a double-side coated 
silver halide emulsion layer material suited for radiography with 
fluorescent intensifying screens but free from antistatic layers and 
containing no antistatic agents is mentioned in said Table 1 at E. The 
surface resistivity of an unsubbed polyethylene terephthalate support free 
from antistatic layer is mentioned at the bottom of Table 1 at P. 
TABLE 1 
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Material Surface resistivity 10.sup.10 .multidot. ohm/sq. 
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A1 50 
A2 22 
A3 8.3 
A4 140 
A5 630 
A6 100,000 
B1 38 
B2 55 
B3 15 
C1 7.0 
C2 6.3 
C3 4.8 
E 3,000 
P 5,000 
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EXAMPLE 2 
TEST 1 
Material A3 of Example 1 is dipped into a 1N aqueous solution of 
hydrochloric acid and thereupon washed to neutral with demineralized 
water. 
TEST 2 
Material A3 of Example 1 is dipped into a 1N aqueous solution of sodium 
hydroxide and thereupon washed to neutral with demineralized water. 
The surface resistivity values obtained before and afer carrying out said 
tests are listed in the following Table 2. 
TABLE 2 
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Test No. Before test After test 
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Surface resistivity 10.sup.10 .times. ohm/sq at 30% R.H. 
1 8.3 8 
2 8.3 36 
Surface resistivity 10.sup.10 .times. ohm/sq at 70% R.H. 
1 0.017 0.018 
2 0.063 0.080 
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