Method of subbing a polyester base

A method of preparing film base material consisting of biaxially oriented synthetic linear polyester of highly hydrophobic character is provided which comprises coating as a layer on to a layer-receptive film of linear polyester a solution of or an aqueous latex of PA1 (a) a copolymer of the type used to prepare a subbing layer for hydrophobic film base material and PA1 (b) 1.5 to 25% by weight of the copolymer present of a compound which contains an active methylene group, and then drying the coated layer and completing the orientation if it has not been fully oriented. The film base material is useful for preparing photographic material by coating directly on the copolymer subbing layer a gelatino silver halide emulsion layer. The gelatino silver halide emulsion layer adheres very strongly to the subbing layer. Further the separation of the layers or frilling is prevented when processing the photographic material.

This invention relates to synthetic film materials, and more particularly 
to film base materials of use in the production of photographic materials. 
It is known that self-supporting films formed of synthetic linear 
polyesters, particularly of the polyesters formed by reaction of ethylene 
glycol and terephthalic acid, may be prepared with mechanical and physical 
and chemical properties which, for example, render them very suitable 
indeed as base materials on which may be coated silver halide photographic 
emulsion layers for the production of photographic film materials. 
However, since such base materials are inherently highly hydrophobic and 
the usual gelatino silver halide emulsions are highly hydrophilic, there 
is great difficulty in securing adequate anchorage between the base film 
and the emulsion layer, especially bearing in mind that the anchorage must 
remain firm throughout the processing sequence of the final photographic 
film. 
It is known to deal with such a difficulty by the provision of an anchoring 
layer or layers (so called "subbing" layers) between the film base and the 
emulsion layer, but the materials hitherto suggested for this purpose in 
connection with other film bases have not always proved entirely 
satisfactory when applied to film base of biaxially oriented synthetic 
linear polyesters of highly hydrophobic character. 
Therefore according to the present invention there is provided a method of 
preparing film base material consisting of biaxially oriented synthetic 
linear polyester of highly hydrophobic character which comprises coating 
as a layer on to a layer-receptive film of linear polyester a solution of 
or an aqueous latex of 
(a) a copolymer of the type used to prepare a subbing layer for hydrophobic 
film base material and 
(b) 1.5 to 25% by weight of the copolymer present of a compound which 
comprises an active methylene group, and then drying the coated layer and 
completing the orientation if it has not been fully oriented. 
Preferably the amount of compound (b) is 7.5 to 17.5% by weight. 
By "layer receptive film of linear polyester" is meant either a film of 
linear polyester which is in a state in which it is receptive to a coating 
of an aqueous latex or solution of a copolymer or which has been 
pretreated to render it receptive to a coating of an aqueous latex or 
solution of a copolymer. 
A polyester film which has been biaxially oriented is high hydrophobic but 
a film of polyester which has not been oriented at all or which has been 
oriented in one direction only is receptive to a subbing coat. If such a 
subbing coating applied to a polyester film which has been oriented in one 
direction only is dried, the polyester film can then be oriented in the 
second direction and the applied coating, as long as it comprises 
polymeric material which is above its second order transition temperature 
during the stretching, will remain firmly anchored on the polyester film. 
This coating will then form a layer on to which more hydrophilic coatings 
can be applied. It is possible to coat polyester film which has not been 
oriented at all with a hydrophilic layer and then to stretch it in two 
directions with the coating on it but this is not advantageous as the 
coating requires to be thicker which can lead to a poorer coating quality. 
Alternatively polyester film material and in particular biaxially oriented 
polyester film material may be treated so as to render its surface 
receptive to an applied coating. 
Preferably the treatment of the surface of the film of synthetic linear 
polyester which enables a polymer layer to adhere thereto is to coat on to 
the surface of the polyester film an organic solvent solution or aqueous 
solution of a phenolic adhesion promoting agent and then to remove the 
solvent, preferably by evaporation. 
Synthetic organic solvents in which to dissolve the phenolic adhesion 
promoting agents are methanol, ethanol, methyl ethyl ketone, acetone, 
dioxan and mixtures thereof. 
By "phenolic adhesion promoting agent" is meant a phenol-based or 
naphthol-based compound which is capable of acting on the polyester film 
base so as to render its surface more receptive to an applied layer. 
Examples of such compounds are m-cresol, o-cresol, resorcinol, orcinol, 
catechol, pyrogallol, 1-naphthol each of which compounds may be 
substituted with one or more chloro-, fluoro- or nitro substituents and 
phenol substituted with one or more chloro-, fluoro- or 
nitro-substituents. The action of the adhesion promoting agent on the 
polyester film base is thought to be swelling action and polyester 
surfaces so treated are receptive to certain polymeric subbing layers but 
not to hydrophilic layers for example a gelatin or polyvinyl alcohol. 
Alternatively the film of polyester may be treated by a physical method, 
for example corona discharge treatment, which renders the surface capable 
of accepting a polymer layer as described in British patent specification 
Nos. 1,262,127, 1,267,215 and 1,286,457. 
However the particular advantage of the method of the present invention is 
that the latex or solution containing the copolymer and active methylene 
group containing compound can be coated onto a film of linear polyester 
which has been oriented in one direction only. This coating is then dried 
to form an adherent layer and the orientation in the second direction can 
then be effected to produce biaxially oriented polyester film base. A 
hydrophilic layer for example a silver halide emulsion can then be coated 
on to the coated side of the film base and this emulsion layer will remain 
firmly adherent to the film base, without the need for an intermediate 
gelatin layer, thus reducing the number of coating operations required. 
With regard to the copolymers used to prepare a subbing layer for 
hydrophobic film base a great many have been proposed and several have 
been used in practice. Most commonly such copolymers are based on 
vinylidene chloride together with at least one plasticising comonomer, 
i.e. a comonomer which renders vinylidene chloride, less crystalline thus 
improving its film forming properties. 
Examples of particularly suitable plasticising comonomers are 
acrylonitrile, alkyl acrylate and alkyl methacrylate. 
According to a preferred form of the present invention there is provided a 
method of preparing film base material consisting of biaxially oriented 
synthetic linear polyester of highly hydrophobic character which comprises 
coating as a layer on to a layer-receptive film of linear polyester a 
solution of or an aqueous latex of a copolymer which has been prepared by 
copolymerising 
(a) vinylidene chloride, at least one plasticising comonomer selected from 
acrylonitrile, alkyl acrylate and alkyl methacrylate, and optionally other 
comonomers, and 
(b) 1.5 to 25% by weight of the copolymer present of a compound which 
comprises an active methylene group, and then drying the coated layer and 
completing the orientation if it has not been fully oriented. 
With regard to this copolymer when used to form a subbing layer the 
presence of the vinylidene chloride causes the copolymer to adhere well to 
polyester, however the presence of a plasticising comonomer is required to 
decrease the tendency of the vinylidene chloride to form a crystalline 
layer. The preferred plasticising comonomers are lower alkyl (i.e. 1-6 
carbon atoms) acrylate and methacrylate esters for example methyl 
methacrylate and methyl acrylate. 
Other comonomers, units of which may be present in the copolymer are acids, 
for example acrylic acid, methacrylic acid, itaconic acid, maleic acid, 
fumaric acid, crotonic acid, mesaconic acid and citraconic acid. Yet other 
comonomers, units of which may be present in the copolymer are comonomers 
which comprise an active halogen group. 
Particularly suitable comonomers having an active halogen group are allyl, 
methallyl or vinyl compounds of the general formula 
##STR1## 
wherein p is 0 or 1, R.sub.11 is hydrogen or methyl when p is 1 but is 
hydrogen when p is 0, X.sub.1 is bromine or chlorine and R.sub.12 and 
R.sub.13 are each hydrogen or methyl or are the same halogen atom as 
X.sub.1, 
or a vinyl component containing an active halogen group the monomer of 
which has the general formula 
##STR2## 
wherein X.sub.2 is chlorine or bromine. 
Formula (1) covers two classes of monomers: allyl or methallyl halogeno 
esters of the general formula 
##STR3## 
and vinyl halogeno esters of the general formula 
##STR4## 
wherein in the above formulae (3) and (4) R.sub.11, R.sub.12, R.sub.13 and 
X.sub.1 have the meanings given to them above. 
The allyl or methallyl halogeno esters of formula (1) may be prepared by 
reacting allyl or methallyl alcohol with the appropriate halocarboxylic 
acid. 
The vinyl halogeno esters of general formula (1) may be prepared by 
reacting acetylene with the appropriate halocarboxylic acid in the 
presence of a catalyst, for example mercuric oxide or by the 
transvinylation reaction between vinyl acetate and the appropriate 
halocarboxylic acid. 
The halomethyl vinyl ketones of formula (2) may be prepared by the method 
of Cath et al, J. Chem. Soc. 1948, page 278. 
Preferably the copolymer comprises from 20 to 95% by weight of vinylidene 
chloride and at least 5% by weight of the plasticising comonomer. Suitable 
copolymers comprise from 20 to 95% by weight of vinylidene chloride, from 
5 to 50% by weight of plasticising comonomer, 0 to 20% by weight of 
copolymerisable acid and 0 to 25% by weight of other comonomers. 
Especially suitable copolymers comprise from 60 to 85% by weight of 
vinylidene chloride, from 7 to 20% by weight of lower alkyl acrylate or 
methacrylate, from 0 to 3% by weight of itaconic acid and from 0 to 20% by 
weight of a comonomer having an active halogen group. 
Examples of suitable copolymers contain vinylidene chloride (81% by 
weight), methyl acrylate (7.7%), allyl monochloroacetate (9.4%) and 
itaconic acid (1.9%) vinylidene chloride (90%), methyl acrylate (8.0%) and 
itaconic acid (2.0%); vinylidene chloride (54.7%), methyl acrylate 
(21.6%), allyl aceto acetate (9.3%) and acrylic acid (14.4%). The 
preparation of these copolymers is set forth hereinafter. 
Other suitable copolymers are copolymers of vinylidene chloride with vinyl 
chloride and optionally other comonomers. Examples of others comonomers 
which may be present are the monomer acids as hereinbefore set forth and 
monomers having an active halogen group as hereinbefore set forth. 
Examples of particularly suitable copolymers based on vinylidene 
chloride/vinyl chloride are those which contain vinylidene chloride (50% 
by weight) and vinyl chloride (50% by weight). 
Other suitable copolymers are those based on vinyl halogeno-esters of 
formula (4) as hereinbefore set forth and particularly vinyl 
monochloroacetate as described in British patent specification Nos. 
1,088,906, 1,143,843, 1,141,395 and 1,208,821. Particular copolymers of 
this type are those described in No. 1,208,821 which comprise a vinyl 
halogeno ester and at least one other monomer copolymerisable therewith, 
the said monomer or at least one of the said monomers being selected so 
that the final copolymer has a softening point lower than that of the 
product obtained by polymerisation in the absence of the said selected 
monomer or monomers. A particularly suitable vinylmonochlorester is 
vinylmonochloracetate. Examples of comonomers having a softening point 
effect are alkyl acrylates, alkyl methacrylates, polyalkylene oxide 
itaconates and maleates, vinyl alkyl esters, vinyl esters, alkenes, 
alkadienes and alkyl styrenes. Especially suitale monomers are ethyl 
acrylate, 2-ethylhexyl acrylate, vinyl isobutyl ether and ethylene. 
Examples of other comonomers which may be present are allyl alcohol, vinyl 
alcohol, vinyl acetate, acrylonitrile and acrylamide. 
Preferably such copolymers comprise from 70-95% by weight of the vinyl 
halogeno ester, from 3-20% by weight of the softening comonomers and from 
0-10% by weight of another monomer. 
The copolymers can be prepared and coated as an organic solvent solution 
or, preferably, as an aqueous latex. 
When the copolymer is made as a latex, the compound which contains an 
active methylene group to be at least slightly water soluble to the extent 
of at least 2 g/liter. By compound which comprises an active methylene 
group is meant a compound which has a methylene group having at least one 
free hydrogen atom attached thereto and having either a methyl or ethyl 
substitute group or another free hydrogen atom attached thereto and which 
compound is substituted by two electron withdrawing groups so located in 
relation to the methylene group that the hydrogen atom or atoms of the 
methylene group has an appreciable acidic character, i.e. the pK.sub.a 
values are not greater than about 16 and preferably not greater than 12. 
The usual activating groups are either a --CN group or a 
##STR5## 
group. 
Suitable compounds having an active methylene group are compounds of the 
general formula 
EQU R--CO--CH.sub.2 --CN (5) 
or formula 
EQU R--CO--CH.sub.2 --CO--R.sup.1 ( 6) 
or formula 
EQU R--CO--CH.sub.2 --CH.sub.2 --CO--R.sup.1 ( 7) 
or formula 
##STR6## 
wherein in the above four formulae R and R.sup.1 are each alkyl, hydroxy 
alkyl, alkenyl of up to 5 carbon atoms, aryl such as phenyl, hydroxy or 
hydrogen. 
Other suitable compounds containing active methylene groups are the vinyl 
ketone compounds of formula 
##STR7## 
wherein Q is CN or 
##STR8## 
or vinyl acetates of the general formula 
##STR9## 
wherein Z is --CN, --COCH.sub.3 or --CO--C.sub.6 H.sub.5 where the phenyl 
group may be further substituted by for example halogen, nitro, lower 
alkyl, or lower alkoxy groups of 1 to 5 carbon atoms. 
The acetoxymethyl vinyl ketone may be prepared from chloromethyl vinyl 
ketone (prepared by the method of Cath et al, J. Chem. Soc. 1948, page 
278) by the method described by A. Arbuzow and A. M. Korolev. Zhurnal 
Obshchei Khimii. Vol. 32, No. 11, pp 3674-3676. November 1967. 
The cyanomethyl vinyl ketone may be prepared by the reaction of potassium 
cyanide and chloromethyl vinyl ketone. 
The vinyl cyanoacetate and benzoyl and ring substituted benzoyl acetate may 
be prepared by the transvinylation reaction as described in U.S. Pat. No. 
3,093,161. 
The vinyl acetoacetate may be prepared by the pyrolysis of ethylene glycol 
esters as described in German Offenlegungsschrift No. 2,142,419. 
Examples of suitable allyl or methallyl monomers having an active methylene 
group which are of use in the present invention are compounds of the 
general formula 
##STR10## 
wherein W is --CN or --COCH.sub.3, X is O, NH or S, and R.sub.14 is 
hydrogen or methyl. 
The allyl or methallyl cyano acetate of formula (11) may be prepared by 
reacting allyl or methallyl alcohol with cyanoacetic acid. 
The allyl or methallyl cyanoacetamides may be prepared as described in U.S. 
Pat. No. 2,808,331. 
Allyl or methallyl acetoacetates may be prepared by the noncatalytic ester 
exchange reaction of beta-keto carboxylic acid esters as described in U.S. 
Pat. No. 2,693,484. 
The allyl or methallyl acetoacetamides may be prepared by the reaction of 
diketene with allyl or methallyl amine. 
The alkyl or methallyl acetothioacetates may be prepared by reacting allyl 
or methallyl mercaptan with diketene. 
The allyl or methallyl cyano thioacetates may be prepared by the reaction 
of allyl or methallyl mercaptan with cyanoacetyl chloride. 
Other suitable compounds not of formula (9) or (10) are .beta.-diketones 
such as 2,4-pentanedione, .beta.-keto esters such as alkyl aceto acetates, 
.beta.-dicarboxylic acid derivatives such as dialkyl malonates, malonic 
acid and malonitrile and cyano esters such as alkyl cyanoacetates. Yet 
other suitable compounds containing active methylene groups are levulinic 
acid which is of formula (7) and 3-methyl-2,4-pentanedione which is of 
formula (8). 
The preferred compounds are allylacetoacetate, malonic acid, cyanoacetic 
acid and 2,4-pentanedione. 
In the method of the present invention the latex of the copolymer or the 
solution of the copolymer is prepared and the compound containing the 
active methylene group may be added to the latex or solution as a fine 
solid or liquid depending on its normal state. If the copolymer is present 
as a latex the compound containing the active methylene group may be added 
as an aqueous solution. If the copolymer is present as an organic solvent 
solution the compound containing the active methylene group may be added 
as an organic solvent solution. 
The film base material prepared by the process by the process of the 
present invention is able to accept a hydrophilic layer adherent thereto, 
for example a gelatin based layer, a polyvinyl alcohol layer or polyvinyl 
acetal layer. 
The gelatin based layer may be a gelatino silver halide emulsion layer but 
sometimes when the process of the present invention is employed to prepare 
film base material for use in the production of photographic gelatino 
silver halide material an intermediate gelatin layer is provided between 
the copolymer layer as hereinbefore defined and the silver halide emulsion 
layer. 
However as stated and illustrated in the following Examples it is possible 
to coat directly on to the copolymer layer a gelatino silver halide 
emulsion layer. The gelatino silver halide emulsion layer adheres very 
strongly to the copolymer subbing layer on the film base and neither the 
gelatin layer nor the subbing layer fall away from the polyester film 
during either prolonged aqueous processing or water washing. 
The particular advantages of eliminating gelatin subbing layers are the 
reduction in the number of operations thus minimising potential defects, 
as well as, in the case of interdraw coating, the possibility of all of 
the coatings being carried out in one continuous operation on one machine. 
Therefore according to a preferred aspect of the present invention there is 
provided a process for the preparation of silver halide photographic 
material which comprises preparing a uniaxially oriented film of 
polyester, coating as a layer on this film an aqueous latex of 
(a) a copolymer of the type used to prepare a subbing layer for hydrophobic 
film base and 
(b) 1.5 to 25% by weight of the copolymer present a compound which 
comprises an active methylene group then drying the coated layer and 
completing the orientation and then coating on to the dried layer a 
gelatino silver halide layer and drying the silver halide emulsion layer. 
When the hydrophilic layer to be applied to the film base material as 
prepared by the process of the present invention is polyvinyl alcohol or 
polyvinyl acetal such a hydrophilic layer may comprise a light-sensitive 
diazonium salt to produce a diazotype material. 
Alternatively after a polyvinyl alcohol or polyvinyl acetal layer has been 
coated on to the film base material as prepared by the process of the 
present invention the polyvinyl alcohol or polyvinyl acetal may have 
incorporated therein or be coated with a light-sensitive diazonium salt to 
produce a diazotype material. 
It is to be understood that the process of the present invention covers not 
only the process of preparing subbed biaxially orientated linear polyester 
film base but the polyester film base when so prepared as well as 
photographic material having coated on the film base at least one 
light-sensitive layer.

PREATION 1 
Vinylidene chloride (60.6 g) was mixed together with 23.9 g of methyl 
acrylate, 15.9 g of acrylic acid and 10.3 g of allyl cyanoacetate in 100 
ml of methyl ethyl ketone to give 50% by volume solution, the temperature 
of the methyl ethyl ketone being below 25.degree. C. Then as 
copolymerisation initiator 1.0 g of 2,2'-azobisisobutyronitrile was added 
to the monomer solution. The solution was maintained at 40.degree. C. 
until the copolymerisation was complete, which took 6 days. 
Infra-red spectra and titrimetric analysis showed that substantially all 
the monomers had been incorporated into the copolymer which thus contained 
about 54.7% by weight vinylidene chloride, 21.6 wt % methyl acrylate, 14.4 
wt % acrylic acid and 9.3 wt % allyl cyanoacetate. This copolymer was used 
in the examples which follow and is referred to therein as copolymer 1. 
PREATION 2 
A second copolymer was prepared similarly using vinylidene chloride 60.6 g 
(50 ml), methyl acrylate 23.9 g (25 ml), acrylic acid 15.9 g (15 ml) and 
allyl acetoacetamide 10.4 g (10 ml). The resulting copolymer contained 
vinylidene chloride 54.7 weight %, methyl acrylate 21.6 wt %, acrylic acid 
14.4 wt %, allyl acetoacetamide 9.3 wt %. 
This copolymer was also used in the Example 1 and is referred to therein as 
copolymer 2. 
PREATION 3 
A third copolymer was prepared similarly using vinylidene chloride 60.6 g 
(50 ml), methyl acrylate 23.9 g (25 ml), acrylic acid 15.9 g (15 ml) and 
allyl acetoacetate 10.3 g (10 ml). The resulting copolymer contained 
vinylidene chloride 54.7 weight %, methyl acrylate 21.6%, acrylic acid 
14.4% and allyl acetoacetate 9.3%. 
This copolymer was also used in the examples and is referred to therein as 
copolymer 3. 
PREATION 4 
To 240 ml of de-oxygenated water was added vinylidene chloride (80 ml), 
methyl acrylate (10 ml) allyl monochloroacetate (10 ml), itaconic acid 
(2.25 g), sodium metabisulphite (1 g), sodium persulphate (1 g), alkyl 
aryl poly glycidol condensate (0.2 g), sodium alkyl aryl poly(oxyethylene) 
sulphate (0.9 g) and the mixture stirred at 25.degree. C. during 
polymerisation under nitrogen. 
This latex was used in the examples and is referred to therein as latex 1. 
It comprises 81% by weight of vinylidene chloride, 7.7% by weight of 
methyl acrylate, 9.4% by weight of allyl monochloracetate and 1.9% by 
weight of itaconic acid. 
PREATION 5 
A latex was prepared as in Preparation 4 but the quantities of monomers 
added were as follows: 
vinylidene chloride: 80 ml 
methyl acrylate: 10 ml 
itaconic acid: 2.25 g 
The resulting latex comprised vinylidene chloride 90% by weight, methyl 
acrylate 8.9% itaconic acid 2.0%. 
The latex of this preparation is designated latex 2. 
PREATION 6 
A latex was prepared as in preparation 5 but the quantities of monomers 
added were as follows: 
vinylidene chloride: 80 ml 
methyl acrylate: 10 ml 
allyl aceto acetate: 10 ml 
The resulting latex comprised vinylidene chloride 82.5% by weight, methyl 
acrylate 7.9% and allyl aceto acetate 9.6%. 
The latex of the preparation is designated latex 3. 
EXAMPLE 1 
The following coatings were applied sequentially to biaxially oriented film 
based on the synthetic linear polyester obtained from ethylene glycol and 
terephthalic acid which is highly hydrophobic. 
First Coating 
solution of 
p-Chloro-m-cresol: 2 g 
Methanol: 100 ml 
dried 2 minutes at 70.degree. C. 
Second Coating 
solution of Copolymer 1. 
to which is added 10% by weight of cyanoacetic acid in methyl ethyl ketone: 
100 ml, 
dried at 100.degree. C. for 5 minutes. 
A number of similar subbed film bases were prepared using in the second 
coating the following: 
Example 2 used copolymer 1 solution+10% by weight of methyl aceto acetate. 
Example 3 used copolymer 1 solution+71/2% by weight of allyl aceto acetate. 
Example 4 used copolymer 1 solution+121/2% diethyl malonate 
Example 5 used copolymer 1 solution+121/2% malonic acid 
Example 6 used copolymer 2 solution+15% ethyl aceto acetate 
Example 7 used copolymer 3 solution+121/2% 2,4-pentane dione 
Example 8 used copolymer 3 solution+10% acetoxymethyl vinyl ketone 
______________________________________ 
Example 9 used copolymer 1 alone 
comparison examples. 
Example 10 used copolymer 3 alone 
______________________________________ 
A similar set of coatings was prepared using the aqueous latexes instead of 
the organic solvent solutions in the second coating. 
Example 11 used latex 1 with 10% by wt. of methyl aceto acetate 
Example 12 used latex 1 with 10% by wt. of allyl aceto acetate 
Example 13 used latex 1 with 15% by wt. of diethyl malonate 
Example 14 used latex 2 with 171/2% by wt. of ethyl aceto acetate 
Example 15 used latex 3 with 15% malonic acid 
Example 16 used latex 3 with 15% sodium cyanoacetate 
______________________________________ 
Example 17 used latex 2 alone 
comparison example 
Example 18 used latex 3 alone 
______________________________________ 
A third set of coatings was prepared by interdraw coating the latexes and 
active methylene compounds as used above. 
The latex and active methylene compound was coated onto uniaxially oriented 
polyester prepared by extrusion onto a chilled drum, heating to between 
80.degree. and 100.degree. C. and stretching over capstan rollers of 
increasing circumferential speed to a draw ratio of about 3. 
The copolymer layer was dried at about 90.degree. C. and the polyester was 
stretched laterally in a stenter apparatus at between 80.degree. and 
100.degree. C. to a ratio of about 3. 
The biaxially oriented polyester was heat set at 210.degree. C. while the 
tension was maintained for 1-4 minutes. 
Example 19 used latex 1 with 10% by wt. of methyl aceto acetate 
Example 20 used latex 1 with 10% by wt. of allyl aceto acetate 
Example 21 used latex 1 with 15% by wt. of diethyl malonate 
Example 22 used latex 2 with 171/2% by wt. of ethyl aceto acetate 
Example 23 used latex 3 with 15% malonic acid 
Example 24 used latex 3 with 15% sodium cyanoacetate 
______________________________________ 
Example 25 used latex 2 alone 
comparison example 
Example 26 used latex 3 alone 
______________________________________ 
The bases so prepared in the preceeding examples were directly coated with 
a gelatino silver halide emulsion and were tested for adhesion in the 
usual manner. 
Two types of adhesion are important the first is dry adhesion. This 
adhesion relates to the copolymer on the base and to the hydrophilic layer 
coated on the copolymer layer, the object of subbing being of course to 
enable the hydrophilic layer to remain firmly adherent on to the 
hydrophobic film base. The hydrophilic layer may be an anti-halation 
backing layer or a photosensitive layer e.g. a silver halide emulsion 
layer. It is important that other layers remain firmly anchored to the 
base when the film material is finished, i.e. cut up into small strips and 
enclosed in cassettes or spooled up. Further it is important that the 
hydrophilic layers do not frill off when the film is placed in the camera 
or when removed from the camera. 
There are no recognised standard dry adhesion tests. However the following 
two tests were carried out on strips of the sets of samples as prepared 
above each of which had been coated with a silver halide emulsion layer. 
__________________________________________________________________________ 
Tear test. (strip torn) 
Small Large 
Large areas 
Effect 
No stripped 
stripped 
peeled 
Whole coating 
Observed. 
fringe. 
fringe. 
fringe. 
away. peels off. 
Arbitrary 
Grade. 
1 2 3 4 5 
__________________________________________________________________________ 
Taped test. (razor cuts made on surface of strips, tape 
applied and torn away.) 
No Whole 
Effect 
coating 
Small amount 
More Large areas 
coating 
Observed 
removed. 
removed. 
removed. 
removed. 
removed. 
Arbitrary 
Grade 
1 2 3 4 5 
__________________________________________________________________________ 
Strips of the samples prepared above were subjected to these two dry tests, 
the results of which are shown in Table 1. The figures shown correspond to 
the Arbitrary Grade listed above. 
Table 1. 
______________________________________ 
Dry adhesion grading. 
Test 
Sample Tear Tape 
______________________________________ 
a) solvent 
coatings 
1 1 1 
2 2 2 
3 1 1 
4 2 2 
5 1 1 
6 1 2 
7 1 1 
8 1 1 
9 2 3 
10 2 3 
b) latex 
coatings 
11 2 2 
12 1 1 
13 3 3 
14 2 2 
15 1 1 
16 1 1 
17 4 4 
18 4 4 
c) interdraw 
latex 
coatings 
19 2 2 
20 1 1 
21 2 3 
22 1 1 
23 1 2 
24 1 1 
25 2 3 
26 2 2 
______________________________________ 
Wet Adhesion 
The film base of the present invention is of particular use as photographic 
film base in which case at least one photographic silver halide emulsion 
layer is coated on the subbed film base. 
Such photographic film material is usually processed in a sequence of 
aqueous processing baths and it is very important that all the final image 
layer is retained firmly on to the base. 
A typical processing sequence comprises immersion in the listed aqueous 
baths in the period stated, alkaline developer bath 3 minutes, acid 
stop-bath 1 minute, acid fix bath 10 minutes, aqueous washing in 
circulating water 20 minutes, followed by hot air drying. 
However some modern processes particularly when forced development is 
required employ immersion in stronger alkaline solutions for longer 
periods. Thus a separate alkaline test was also included. This consisted 
in immersing the samples in 1% sodium hydroxide solution for 10 minutes 
followed by a normal washing. The samples were subjected to a scratch/rub 
test after wet processing this consisted of making a scratch mark in the 
coating on the film while still wet and then rubbing the film surface 
perpendicular to the scratch. 
______________________________________ 
Wet tests. 
Effect No peeling Some Areas of All emulsion 
observed. 
of emulsion. 
peeling. 
emulsion litft. 
lifts away. 
Arbitrary 
Grade. 1 2 3 4 
______________________________________ 
Strips of the samples prepared above were subjected to these wet tests and 
the results are shown in Table 2. The figures shown correspond to the 
Arbitrary Grades listed above. 
Table 2. 
______________________________________ 
Wet adhesion grading. 
Test 
Sample dev fix wash 1% alkali 
______________________________________ 
a) solvent 
coatings. 
1 1 1 1 1 
2 1 1 1 1 
3 1 1 1 1 
4 2 2 1 2 
5 1 1 1 1 
6 1 1 1 1 
7 1 1 1 1 
8 1 1 1 1 
9 3 3 3 3 
10 3 2 2 3 
b) latex 
coatings. 
11 1 1 1 1 
12 1 1 1 1 
13 1 1 1 2 
14 1 1 1 1 
15 1 1 1 1 
16 1 1 1 1 
17 2 2 2 2 
18 2 3 2 2 
c) interdraw 
latex 
coatings. 
19 2 2 2 2 
20 1 1 1 1 
21 2 2 2 2 
22 1 1 1 1 
23 1 1 1 1 
24 1 1 1 1 
25 4 4 4 4 
26 4 4 4 4 
______________________________________ 
These results show that the layers in film material made using the film 
base according to the present invention exhibits very good adhesion but 
the layers in film material made using the film base not according to the 
present invention, that is to say when the subbing assembly used did not 
comprise any compounds of formulae (5) to (11) (samples 9, 10, 17, 18, 25 
and 26), did not exhibit adequate adhesion.