Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
108;~090
CONTAINER FOR A FLUID PHOTOGRAPHIC PROCESSING MATERIAL
The invention relates to a container for a fluid photo-
graphic processing material containing aromatic alcohol
comprising a pair of opposed walls marginally sealed together
over a substantial area to provide an internal cavity adapted
to retain such material, at least one of said walls being
flexible and deformable, the internal surfaces of said walls
bounding said cavity comprising a polymer which resists
deterioration by the action of such processing material,
said opposed walls being marginally sealed together over a
10 first part of said area polymer-to-polymer, and a polymeric
sealing composition interposed between said opposed walls
over a second part of said area forming a seal of less
strength than the seal over said first part of said area,
whereby said container opens along said second part of said
area upon the application of pressure to said container.
Homopolymers and copolymers suitable for forming the
relatively weak burst seal in a pod have been known. Such
seal materials are generally located along that edge of a
pod which is intended to burst for releasing the photographic
20 developer, and are coated over an inner layer of the pod
which is poly(vinyl chloride) or other polymer that resists
the developer.
Reference is made to the following representative
patents and a publication describing the named seal compositions
and others:
: :
108Z090
U.S. 3,056,491 describes plasticIzed and unplasticized
polyvinyl butyral; also a composition comprising poly(vinylidene
chloride), polyacrylonitrile - poly(vinyl chloride), and an
acrylic ester resin.
U.S. 3,056,492 describes cellulose nitrate - acrylic
ester resin composition.
U.S. 3,438,550 describes vinylidene chloride - nitrocellulose.
ethyl cellulose - acrylic ester resin.
U.S. 3,750,907 describes a mixture of cellulose nitrate
or alcohol soluble cellulose acetate butyrate with styrene-
methyl methacrylate copolymer or toluene soluble cellulose
acetate butyrate or poly(vinyl butyral), and a mixture, with
a plasticizer, of alcohol soluble cellulose acetate butyrate,
or a copolymer of bisphenol A with epichlorohydrin, or
toluene soluble cellulose acetate butyrate.
Research Disclosure, November 1974, Item 12713 describes
poly(2-norbornylmethyl methacrylate);
poly[cyclohexyl methacrylate-co-5(6)-methyl-mercapto-
2-norbornylmethyl methacrylate];
polyhydroxy ether resulting from copolymerization of
bisphenol A with epichlorohydrin;
poly(cyclohexyl methacrylate);
U.S. 2,634,886 teaches a pressure rupturable fluid
container having a seal on one edge which is more easily
rupturable than the seals of the other edges. The sealing
composition proposed in this patent is ethyl cellulose or an
ethyl cellulose and paraffin mixture. The problem underlying
'
. .
. .
1(~8ZO9O
this prior art teaching is, however, quite different from
the present teaching, because the prior art is not faced
with the problem of holding photographic solutions, which
contain an aromatic alcohol and the container of the mentioned
U.S. 2,634,886 is not suited for such fluids.
U.S. 3,459,790 discloses monomeric acrylic ester materials
of a very general formula which form a class of interpolymers
and are useful in the photographic field, especially as
substitutes of gelatin. There is, however, no hint whatsoever
10 that even if crosslinked these substances might be suited as
sealing compositions, especially for solving the specific
problem of holding photographic solutions containing an
aromatic alcohol in a container. ~
U.S. 3,2~3,416 teaches 2-norbornylmethyl esters of acrylic
and methacrylic acids and polymers thereof as being useful
substances in the general field of synthetic polymers. Apart -~
from the fact that the reference does not at all refer to the
specific problem underlying the present invention, the sub-
stances disclosed therein could not even be crossiinked as
20 required in the present teaching due to the absence of a
double bond in the norbornane ring system.
It has long been recognized that some photographic ,-~
developers contain aromatic alcohols such as those having
the formula ~ (CH2)xOH where x is a positive integer
from 1 to 3, for example ~-phenylethyl alcohol, y-phenyl-n- ¦-
propyl alcohol, and benzyl alcohol (see United States Patent
No. 2,304,925). Another is a,a'-xylenediol. Such aromatic
alcohols are solvents for many edge sealing compositions
even though present in the photographic formulation to the
30 extent of only about 1 to 4 percent. With time~ the aromatic
alcohol dissolves prior art compositions, thus allowing contact
o~ the upper and lower poly(vinyl chloride) innermost layers
1082090
of the pod, and these layers fuse together and form a strong
bond that will not break at the desired pressure.
Sometimes it is necessary to apply a small quantity of
liquid material in a thin layer over a fairly large surface
within a piece of apparatus, such as a camera, without
gaining access to the interior of the apparatus. For example,
a photosensitive film may be processed or a photograph may
be toned by applying on the surface thereof within a camera
a layer of a liquid processing reagent, such as a developer
for a silver-halide emulsion, or a solution of a toning
agent. The present invention makes it possible to apply
such a thin layer by incorporating within the apparatus a
disposable fluid container in the form of a pod or pouch
having at least one wall (and preferably two walls) which is -
formed of a flexible compressible material, and having
sealed edge areas which are relatively weak at one part and
relatively stronger at another part for selective opening of
the weak seal area while the stronger edge seals are unbroken -
when the wall is compressed. With this construction, the
flexible container wall or walls can be compressed by an
internal mechanical device, whereupon the liquid contained
within the container is expelled unlformly through the
opened weak seal in the desired direction onto the surface 1 -
to be coated.
It is particularly important that such containers be
so constructed as to resist deterioration in storage as
the result of chemical action by the contained liquids.
Deterioration of the container not only may cause leakage
from the container, but also may cause contamination of the
contained fluid. Also, action of an aromatic alcohol on
the weak edge seal area may cause it to become too strong as a
result of dissolving the seal composition and permitting the
~ .
--4--
~--
.~ -
108Z090
underlying resin areas to fuse together. When this happens,
a camera user may rind that he cannot successfully develop
an exposed film within the camera.
The task underlying the present invention is to overcome
the aforementioned drawbacks and to provide a container for
fluid photographic processing material which will function
properly in the presence of aromatic alcohol in the photographic
processing material.
This task is accomplished by providing the initially-
10 mentioned container, wherein: -
said polymeric sealing composition is one of the - -
following methacrylic acid derivatives:
a) a crosslinked homopolymer or copolymer of 2-
acetoacetoxyethyl methacrylate having the formula I:
CH O O O
. 3 ~
CH2=C - C-O-CH2-CH2-0-C-CH2-C-CH3
(I)
the copolymer being composed of the compound of
formula I and a 2-norbornyl ester of methacrylic acid
having the general formula III:
R"
(CH2)n- - ,C, - ,C CH2
R' O CH3 (III) 1 -
wherein R' is selected from the group consisting of a
hydrogen atom, a straight-chain or branched alkyl group ¦ -
of from 1 to 4 carbons, and a phenyl group; R" is
selected from the group consisting of a hydrogen atom
and an alkyl group of from 1 to 2 carbons; and n is
0 to 3;
--5--
1082090
said homopolymer or copolymer prior to being crosslinked
having an inherent viscosity in benzene or chloroform
measured at a concentration of 0.25 g/deciliter of
solution at 25C ranging from about 0.2 to 1,
or
b) a crosslinked homopolymer of a norbornene derivative
of methacrylic acid ester having the general formula .
~ (CH2)n-0-C-c = CH2
R" (II)
wherein R' is selected from the group consis~ing of a
hydrogen atom, a straight-chain or branched alkyl group ¦
of from 1 to 4 carbons, and a phenyl group, R" is
selected from the group consisting of a hydrogen atom ¦
and an alkyl group of from 1 to 2 carbons, and n is 0
to 3,
6--
:,
108~090
said homopolymer prior to being crosslinked having an
inherent viscosity in benzene measured at a concentration
of 0.25 g/deciliter of solution at 25C ranging from -
about 0.1 to 1.
Further advantageous embodiments are described in the subclaims
and the specification. The values of the inherent viscosity
of the polymers derived from the compound of formula I are
practically identical when measured in benzene or chloroform.
The ratio of compound of formula I to compound of
formula III can vary from 100:0 to 10:90, preferably from
60:40 to 20:80, more preferably from 50:50 to 25:75 by
weight. Also preferred is a ratio of approximately 50:50,
by weight.
All starting monomers are either known or readily
obtainable. The compounds of formula I, and III for example
are described in U.S. Patents 3,459,790 and 3,243,416- --
respectively.
According to the invention the weak seal of a pod is
formed by coating one or both mating edges of a pod with a
layer of the present sealing composition.
The term "alkyl group with 1 to 2 carbons" is meant to
include methyl and ethyl.
The term "straight-chain or branched alkyl group with 1
to 4 carbons" is meant to include methyl, ethyl, n-propyl,-
i-propyl, n-butyl, i-butyl, sec.-butyl and tert.-butyl.
The term "n" in the general FormulP III of claim 3 is 0
to 3, but preferably 0 to 1.
A) homopolymers and copolymers of the monomer of formula I: ~ -
The homopolymer and copolymers of the monomer of formula I ~-
can be prepared by conventional addition polymerization ~-
reactions.
1~)8ZO9O
Advantageously the copolymer comprises a 2-norbornylmethyl
ester of methacrylic acid. -
A preferred embodiment is concerned with the use of
crosslinked homo- and copolymers containing units of 2-
acetoacetoxyethyl methacrylate, the homopolymer being some-
times called Polymer H hereinafter, in the preparation of
weak pod seals~ The monomer has the formula:
CH
CH2 = C - C - O - CH2CH23 - C - CH2 - C - CH3-
O O O
(I)
The methylene group (marked by the asterisk) flanked by two
carbonyl groups is an "active methylene" group. When the
homopolymer, poly(2-acetoacetoxyethyl methacrylate) is
heated, it tends to become insoluble, possibly as the result
of the formation of crosslinks via the enol form, or possibly
via hydrogen bond formation involving this form.
This compound reacts with aldehydes, e.g. aliphatic
mono- and dialdehydes of 1 to 10 carbon atoms, e~g. formal-
dehyde, acetaldehyde, propionaldehyde, n- and i-butyraldehyde,
n- and i-valeraldehyde ? n- and i-caproaldehyde~ n- and i-
heptaldehyde? mucochloric acid~ etc " glyoxal~ malondialde-
hyde, succindialdehyde, glutaraldehyde, adipic aldehyde,
pimelic aldehyde, suberic dialdehyde etc.~ especially formal-
dehyde, glyoxal and glutaraldehyde.~
Monoaldehydes are, therefore, difunctional toward
Polymer H, and dialdehydes, such as glyoxal, are tetra-
functional,
Polymer H also reacts with amines. Thus diamines, -
for example aliphatic or aromatic diamines, for example
diamines of the general formula
108zoso
H ,,,H
/ N - (CH2)n - N
R2
wherein Rl and R2 are independently H, alkyl, e.g. alkyl
with 1 to 10, especially 1 to 4 carbon atoms, cycloalkyl,
wherein the ring carbons are optionally replaced by hetero
atoms, like 0, N, S, aryl, e.g. phenyl or alkyl-substituted
phenyl, and wherein n is an integer from 0 to 10, will
therefore act as crosslinking agents.
Ethylene diamine can advantageously be used as a hardener.
In general, crosslinking can be accomplished with any I -
gelatin hardener such as bis(vinyl-sulfonylmethyl) (or ¦-
ethyl-, propyl- or butyl-) ether, bis(vinylsulfonyl)alkanes, and ! - -
aldehydes. The following known compounds are well-suited
for this purpose: bis(vinylsulfonyl)methane, 1,2-bis(vinyl-
sulfonyl)ethane, 1,3-bis(vinylsulfonyl)propane, 1,4-bis(vinyl-
sulfonyl)butane, 1,5-bis(vinylsulfonyl)pentane, 2,2-bis(vinyl-
sulfonyl)propane, N,N'-bis(2-vinylsulfonylethyl)piperazine),
1,2-bis(vinylsulfonylmethoxy)ethane, 1,2-bis(2-vinylsulfonyl-
20 ethoxy)ethane, 1,4-bis(2-vinylsulfonylethoxy)butane, bis[2-
(2-vinylsulfonylethoxy)ethyl]sulfone, N,N'-bis[2-(2-vinyl-
sulfonylethoxy)ethyl]urea, 1,14-bis(vinylsulfony.1)-3,6,9j12-
tetraoxatetradecane, N,N'-bis(2-vinylsulfonylethyl)-n-
propylamine. Advantagéously, the hardener should be used in
an amount between 1 and 2 mols per mol of crosslinkable ~
monomer, but an amount down to as low as 0.25 mol per mol
can also be used. ¦-~
Examples of the use of Polymer H in forming crosslinked ¦~
benzyl alcohol insoluble compositions for pod edge seals
3~ follow. The following polymers were tested:
(1) The homopolymer (Polymer H) of 2-acetoacetoxyethyl
methacrylate
(2) A copolymer of 2-acetoacetoxyethyl methacrylate
- - . - ~ . - . :
1C~8ZO~O
and 2-norbornylmethyl methacrylate containing 50% by weight
of each compound (sometimes called Copolymer C hereinafter);
(3) A copolymer of 2-acetoacetoxyethyl methacrylate
and 2-norbornylmethyl methacrylate containing 25% by weight -
of the former (sometimes called Copolymer D hereinafter).
2-norbornylmethyl methacrylate has the structure:
0 CH3
CH2 - O - C - C = CH2
(IIIa)
--10--
ZO90
and is representative of 2-norbornyl methacrylate esters
having the following general structural formula III (as in
United States Patent 3,243,416), that can be copolymerized
with 2-acetoacetoxyethyl methacrylate:
~CH2)n-0 - ,C, - C, CH2
R~ CH3 . ,
(III)
wherein R' is selected from the group consisting of a hydrogen
atom~ a straight-chain or branched alkyl group of from l to
4 carbons, and a phenyl group; R" is selected from the group
consisting of a hydrogen atom and an alkyl group of from l
to 2 carbons, and n is a whole number from O to 3, preferably
O to l.
Other suitable 2-norbornyl methacrylate esters are:
2-norbornyl methacrylate
3-methyl-2-norbornylmethyl methacrylate
2,3-dimethyl-2-norbornylmethyl methacrylate '
3-phenyl-2-norbornylmethyl methacrylate
2-(,3-methyl-2-norbornyl)ethyl methacrylate
2-(2,3-dimethyl-2-norbornyl~ethyl methacrylate
2-(3_phenyl-2-norbornyl~ethyl methacrylate
2-(2-norbornyl)ethyl methacrylate
3-(,3-methyl-2-norbornyl~propyl methacrylate
3-(2~3-dimethyl-2-norbornyl)propyl methacrylate ,, .
3-(,3.phenyl-2-norbornyl)propyl methacrylate
3-(,2-norbornyl)propyl methacrylate
3-ethyl-2-norbornylmethyl methacrylate
2,3-diethyl-2-norbornylmethyl methacrylate
3-butyl-2-ethyl-2-norbornylmethyl methacrylate
The polymers and copolymers of the invention made from
the monomer of formula I havinga suitable degree of polymerization ~-
. . . - : :.
: ~ ., . . . : -
. .
~(~82090
are those having an inherent viscosity in benzene or chloroform
measured at a concentration of 0.25 g/declliter of solution
at 25C ranging from about 0.2 to 1, preferably about 0.3 to
o.8, most preferably about 0.4 to 0.7.
B) homopolymers of methacrylate esters of norbornene
compounds according to the general formula II:
The rings in compounds having the above general formula
II with crosslinkable ethylenically unsaturated groups are
made by Diels-Alder reactions of cyclopentadiene with variously
substituted alcohols. This limits substitution sites to
those corresponding to the alcohols used.
A preferred embodiment of the invention employs poly(5-
norbornen-2-ylmethyl methacrylate), for simplicity called
Polymer N hereinafter:
., '
~ CH2 - 0 - C C - CH ~
L~ ~
(IIa)
wherein the structure within the brackets represents that of
recurring units in the polymer structure.
The polymers of the invention of the general formula II
having a suitable degree of polymerization are those having
an inherent viscosity in benzene measured at a concentration
of 0.25 g/deciliter of solution at 25C ranging from about
0.1 to 1, preferably 0.2 to o.8, most preferably about 0.3
to 0.8.
Among specific compounds that may be used are:
Poly(5-norbornene-2-yl methacrylate)
Poly(3-methyl-5-norbornene-2-ylmethyl methacrylate)
Poly(2,3-dimethyl-5-norbornene-2-ylmethyl methacrylate)
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1~8Z090
Poly(3-phenyl-5-norbornene-2-ylmethyl methacrylate)
Poly[2-(3-methyl-5-norbornene-2-yl)ethyl methacrylate]
Poly[2-(2,3-dimethyl-5-norbornene-2-yl)ethyl methacrylate]
Poly[2-(3-phenyl-5-norbornene-2-yl)ethyl methacrylate]
Poly[2-(5-norbornene-2-yl)ethyl methacrylate]
Poly[3-(3-methyl-5-norbornene-2-yl)propyl methacrylate]
Poly[3-(2,3-dimethyl-5-norbornene-2-yl)propyl methacrylate]
Poly[3-(3-phenyl-5-norbornene-2-yl)propyl methacrylate]
Poly[3-(5-norbornene-2-yl)propyl methacrylate]
Poly(3-ethyl-5-norbornene-2-ylmethyl methacrylate)
Poly(2,3-diethyl-5-norbornene-2-ylmethyl methacrylate)
Poly(3-butyl-2-ethyl-5-norbornene-2-ylmethyl methacrylate).
The material can for example be deposited from solution
in an organic solvent containing 1 to 10% by weight of
solids, for example poly(5-norbornene-2-ylmethyl methacrylate). -
The invention is further illustrated by the drawing
wherein:
Fig. 1 is a side elevational view, partly broken away
and shown in section, of a photographic developer pod in
20_ accordance with the invention;
Fig. 2 is a perspective view of a blank which can be
folded to form the pod of Fig. l; and
Fig. 3 is a plan view of the pod of Fig. 1.
Figs 1 and 3 show a rectangular container C comprising
an upper wall 11 and a lower wall 12, both of flexible
material, which are sealed together along marginal areas 13,
14, 15 extending around three sides of the container. The -
fourth side 16 is closed as a fold of the laminated sheet
from which the container is formed, but this side also could
comprise two edges sealed together when forming the container
from separate sheets. The internal areas of the container
walls are not sealed together, but are spaced apart to form ~ -
a storage space for liquid in the form of bubble-like protu-
~erances 17, 18 on each side of the container.
. .
.
~08Z090
Now, referring to Fig. 1, the two flexible walls 11
and 12 are of laminated construction and include several
layers which are adhesively joined to one another. Specifically,
layer 21 of strong kraft paper is adhered to layer 23 of metal
foil, such as lead or aluminum which is impervious to the
passage of liquid and to the passage of air from the outside
into the liquid. Such paper-foil laminates are generally
purchased in sheet form as they are readily available on the
market.
The innermost layer 25 is a polymeric resinous material
such as poly(vinyl chloride) or a copolymer of vinyl chloride -
with 2-15 percent by weight of vinyl acetate which is l-
resistant to the action of the contained liquid. Layer 25 can
be applied to the foil by extrusion, or solvent coating, or ¦-
by an adhesive composition. A final layer 22 is the novel
sealing composition of the present invention which is coated
as a narrow strip along one long edge of the pod where a
relatively weak bursting seal is wanted.
The two halves 11 and 12 of the container are
joined together along marginal portions 13, 14, 15 by heat and
pressure sealing. Where the layers of resin 25 are in contact
with one another along edges 13 and 15 a strong seal results
such as 2 to 3 lbs/in. Where the strip 22 along edge 14
contacts layer 25, a relatively weaker bursting seal results
such as 0.3 to 0.7 lb/in. When the photographic processing
liquid is to be expelled through the weak seal on edge 14 by
passing a pair of rolls over the container, the nip of the rolls
can be positioned at the back edge 16 and moved toward the front
edge 14 to break seal 22 and expel the liquid. Success is
30 achieved when the seals at edges 13 and 15 are sufficiently stronger
than weak seal 22 to resist bursting.
-14-
1~8ZO9O
Instead of coating only one strip 22 along the weak
seal edge, both mating edge areas may be similarly coated so
that the final seal along that edge is by one strip to the other.
Side 16 need not be sealed at all for operability,
although it should be sealed for storage purposes. When back
edge 16 is formed by sealing two laminates together, success ~ -
can be achieved when the seal at edge 16 is stronger, weaker,
or the same strength as seal 22. Such a seal on the back ,-
edge can be accomplished with the same coating composition
10 as on edge 14 for ease of manufacture. When seals 16 and 22
are by the same alcohol-resistant composition and are of equal
strength, the container or pod can be positioned wlth either
edge forward for ease in assembly of film packs or rolls.
Referring again to Fig. 1, even though back edge 16
of the container is closed inherently, it is desirable ¦-
to pinch and heat seal the adjoining areas together so as to 1-
form a streamline design to make it easy to pass a pair of
compressing rollers or similar compressing devices across the
container.
Instead of sealing the entire length of edge 14 under
conditions to form a weak seal, it sometimes is desirable
to provide alternating areas of weak and strong sealing to
assure uniform distribution of the liquid contents. For
example, two areas coated with weak sealing material may be -
provided, spaced apart by a central or intermediate area of
strong sealing material (such as the vinyl polymer or copolymer !-
layer) whereby the liquid is ejected in two separate streams
which merge subsequently.
The principle of the invention depends primarily upon
the use of novel sealing compositions which, when locally
coated on a part of marginal sealing areas, react to the
-15- - ;
-: . . - -
1~)8ZO9O
application Or heat and pressure to form seals of lesser
strength than the seals between uncoated marginal areas.
According to the invention it was unexpectedly found
that the present polymeric materials, when crosslinked, form
excellent relatively weak seals for the bursting edge seals
of pods containing photographic developer, which makes such
pods especially useful for in-camera film development.
Furthermore, the relatively weak seals are insoluble in the
presence of an aromatic alcohol and can therefore be employed
to advantage as sealants for pods holding photographic
developers containing such aromatic alcohols. The polymers
of the invention combine such insolubility with the ability
to form burst seals of the desired low strength (0.3-0.7
lb/in) over a wide temperature range. Another advantage is ;
their good resistance to changes in strength as they age in
storage.
The examples which follow serve to further illustrate
the advantageous results achieved by the present teaching.
Examples 1 to 18 relate to homopolymers and copolymers
deriving from the monomeric material of formula I. Examples
19 to 36 relate to homopolymers deriving from the methacrylate
esters of norbornene compounds of the general formula II.
Example 1 - Preparation of poly(2-acetoacetoxyethyl
methylacrylate) - Polymer H
Poly(2-acetoacetoxyethyl methacrylate) was prepared by
refluxing in a 65C bath 100 grams of the monomer, 400 ml of
acetone and 1 gram of 2,2'-azobis(2-methylpropionitrile) for
6 hours. The resulting polymer solution was used in the
following examples.
-16-
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~82090
Example 2 - Preparation of the copolymer poly(2-acetoacetoxy-
ethyl methacrylate-co-2-norbornylmethyl methacrylate)
in 50:50 weight ratio - Polymer C
The copolymer poly(2-acetoacetoxyethyl methacrylate-co-
2-norbornylmethyl methacrylate) in a 50:50 weight ratio was
prepared by refluxing in a 65C bath 10 grams of 2-norbornylmethyl
methacrylate, 10 grams of 2-acetoacetoxyethyl methacrylate,
80 ml of acetone, and 0.80 gram of 2,2'-azobis (2-methylpropioni-
trile) for 24 hours. The resulting copolymer solution was
10 used in the following examples. I
Example 3 - Preparation of the copolymer poly(2-acetoacetoxy- ''
!
ethyl methacrylate-co-2-norbornylmethyl methacrylate) I -
in 25:75 weight ratio - Polymer D
The copolymer in a 25:75 weight ratio was prepared by
refluxing in a 70C bath 75 grams of 2-norbornylmethyl
methacrylate, 25 grams of 2-acetoacetoxyethyl methacrylate,
400 ml of acetone, and 1 gram of 2,2'-azobis (2-methyl- ~
propionitrile) for 94 hours. A portion of the solution was
blended with methanol and the resulting white solid was l
20 dried in a vacuum at 35C for 3 hours. It had an inherent '--
'viscosity {~} = 0.29 (chloroform) and tg = 100.5C. The
remaining portion of the solution was used in the following
examples. 1-
Examples' 4'to 12
~- The general procedure was to dissolve the polymer or
copolymer derived from the compound of formula I in methylene --
chloride (5 ml per gram) and cast a film on a glass slide,
which was then appropriately treated. Stoichiometric amounts
of solutions of the crosslinking additives were added to the
methylene chloride solutions immediately before casting the
films. The glyoxal was used as a 40% by weight solution in
water, the glutaraldehyde, as a 50% by weight water solut~on.
.. ~ .
-17-
. . . ,,- ' . ,: ' - . ~ . : ,~ ' '
1C~82090
One-half of the slide bearing the film was then immersed in
100% benzyl alcohol for one hour, then dried in a vacuum at
100C for one hour, and the two halves of the slide compared
to ascertain the action of the benzyl alcohol. Benzyl
alcohol was used as a conveniently available representative
of aromatic alcohols.
The results are given in Table I.
TABLE I
. Treatment Action in 100% .
Ex. Material Treatment Time Benzyl Alcohol
4 Polymer H Add formalde- 2 hours Insoluble; very
hyde at room swollen
temperature (1)
" Same at 60 to2 hours Insolublej very
65C swollen
6 " Same at room 3 days Insoluble;
temperature swollen
7 " Add formalde- 1 hour Insoluble;
hyde at 70C slightly swollen
(2)
8 " Add glyoxal at1 1/4 Insoluble,
room tempera- hours slightly swollen
ture (3)
9 " . Aad glutaralde-1 hour Insoluble;
hyde at room slightly swollen
temperature (4)
" Add ethylene- 1 hour Insolubie
diamine at swollen
room tempera-
ture (5)
11 Copolymer C Add glyoxal at1 hour Insoluble;
room tempera- swollen
ture (6)
12 Copolymer D Add glyoxal at1 hour Insoluble;
room tempera- moderately
ture (7) swollen
-18-
- -. : - -
l()~ZOgO
-
(1) 20% solids; gelled in 2 minutes
(2) 4% solids; no gel in 3 days
(3) 4% solids; no gel in 3 days.
A 20g solids solution plus glyoxal
gelled in 2 minutes
(4) 4~ solids; no gel in 3 days.
A 20% solids solution plus glyoxal
gelled in 3/4 of an hour.
(5) 4% solids
(6) 4% solids
(7) 4% solids
The testing of the above listed polymers was carried
out under the most drastic conditions by exposing them to
100~ benzyl alcohol for the duration of the experiments. It
is noteworthy that even under these extreme conditions, the
desired insolubility in an aromatic alcohol remained essentially
intact. It is fair to conclude that the desired insolubility
of these polymers will even be better preserved under the
conditions encountered with photographic developer solutions
which are approximately only 4% of the aromatic alcohol.
Reaction with formaldehyde causes crosslinking and the
product is insoluble but swells in 100% benzyl alcohol.
Glyoxal and glutaraldehyde give tightly crosslinked products
that are insoluble and swell very little in 100% benzyl
alcohol. At the low concentration of benzyl alcohol in a
photographic developer, these crosslinked composltions
formed by heating, or those containing the hardeners and --
crosslinking agents formaldehyde, glyoxal, ethylene diamine, and
glutaraldehyde are resistant against being dissolved.
The reaction rate of crosslinking with the aldehydes is
dependent on the polymer concentration in the solution; a 4%
30 solids solution was not gelled by adding, e.g., glyoxal. An
acceptable range is 1 to 10% solids to avoid gelation
before application to form a seal.
Examples of the fabrication of pods using H, C and
D formulations follow. In each example, the solution con- -
taining hompolymer or copolymer, and crosslinking agent when
--19-- `
.: - - , . , . ~ . .. . :.
2090
used, was coated along one edge 22 of a blank, treated (if
desired), and then the blank was folded and the seal effected
by heat and pressure. Coating was at a level of 160 mg/ft2
using a 4% by weight solids solution.
Burst strength of a seal was determined by cutting out
a strip l/2-inch wide perpendicularly across the weak seal
(of an actual pod, or a simulated pod), placing the adjacent
strip sections in sçparate jaws of an Instron tensile tester,
pulling the Jaws apart, noting the force in pounds required
10 to peel the two halves of the seal apart, and doubling the
value to establish the burst strength in lbs/inch.
Example 13
Polymer H was coated from a solution in acetone. After
incubation at 120F (49C) for 3 days, the burst strength-
temperature profile was: sealed at 275F (135C), 0.27
lbs/in; 300F (149C), 0.26 lbs/in; 325F (163C), 0.32
lbs/in; 350F (177C)~ 0.23 lbs/in. These seals were subjected I -
to the action of a solution containing 4% benzyl alcohol and
found to be insoluble.
In this and the following examples the burst strength-
temperature profile serves to demonstrate the wide operational
ranges of the corsslinking methods leading to superior results.
Example 14
A 4% solids solution of Copolymer C in acetone was
treated with glyoxal at the rate of 0.09 gram glyoxal per 8 -~
grams of copolymer. The burst strength-temperature profile
was: sealed at 225F (109C), 0.39 lbs/in; 250F (121C), ~ -
0.74 lbs/in; 275F (135C), 0.72 lbs/in; 300F (149C), o.60
lbs/in. The product of the treatment was insoluble in 100%
30 benzyl alcohol.
Example 15
A 4% solids solution of Copolymer D in acetone, untreated,
was used. Burst strengths varied but little from 0.53 lbs/in
when sealed at 250F (121C) to o.38 lbs/in at 375F (191C).
-20-
. . .
1~82090
The material was not affected by incubation at 145F (63C)
for 3 days. When sealed at 300F (149C), the unincubated
material had a burst strength of o.46 lbs/in. When it was
sealed and then incubated, the strength was 0.30 lbs/in; and
when it was incubated and then sealed the burst strength was
0.45 lbs/in.
Example 16
The solution of Example 15 was treated and crosslinked -
with glyoxal at the rate of 0.19 gram glyoxal per 8 grams
10 polymer. A film of this product was insoluble in 100% -- - -
benzyl alcohol. The temperature-burst strength profile was
broad and well within the desired range as shown in Table
II.
Table II
Sealing
Temperature, F (C) Burst Strength, lbs/inch
225 (107) o.38
250 (121) 0.55
275 (135) 0.49
300 (149) 0.40
20325 (163) o.38
350 (177) 0.44
Incubation for 3 days at 145F (63C) had no effect
on the seal strength.
Example 17
The solution of Example 15 was treated and crosslinked
with glutaraldehyde at the rate of 0.13 gram glutaraldehyde
per 8 grams polymer. The product was insoluble in 100%
benzyl alcohol. The burst strength profile was shifted to
lower temperatures by this substitution of glutaraldehyde
for glyoxal: sealed at 225F (107C), 0.29 lbs/in; 250F
(121C), 0.51 lbs/in; 275F (135C), 0.50 lbs/in.
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1~8'ZOgO
Example 18
A 4% solution in acetone of Polymer H was treated with
ethylenediamine, the crosslinked product was insoluble in
100% benzyl alcohol. The burst seal strength after coating
from a 4% solids solution in acetone was 0.13 lbs/in when
sealed at 400F (204C).
While the foregoing examples relate to copolymers
containing 50% or 25% by weight of 2-acetoacetoxyethyl
methacrylate, the balance being 2-norbornylmethyl methacrylate,
comparatively advantageous results can be secured when the
former comprises 10% to 50% and the latter 90% to 50% by
weight of the copolymer.
The following examples relate to crosslinked poly(5-
norbornene-2-ylmethyl methacrylate) useful in the manufacture
of pod seals.
Example 19 - Preparation of poly(5-norbornene-2-ylmethyl
methacrylate) - Polymer N
5-norbornene-2-ylmethyl methacrylate monomer was prepared
in a flask fitted with a vertical condenser with water at 75C
20 circulating through the jacket, attached at the top to a
downwards cold water-cooled condenser. There were refluxed
for 2 hours 372 grams (3.0 moles) of 5-norbornene-2-methanol,
450 grams (4.5 moles) of methyl methacrylate, 526 grams of
N,N-dimethylformamide, 28.8 grams of hydroquinone, and 8.1
grams (0.15 mole) of sodium methoxide. A total of 252 ml
of distillate was collected (theoretical methanol equals 121 ml).
The flask contents were cooled, diluted with ether, and washed
with water, ex~.ess dilute hydrochloric acid, water, 5% aqueous
sodium hydroxide until the washes were colorless, and again
30 with water. The ether solution was dried with anhydrous sodium
sulfate, 11.5 grams of p-(p--tolylsulfonyl-amido) diphenylamine
were added, and the ether was removed in a rotary evaporator !~
at 60C and about 15 mm pressure. To the residual oil o.58 gram
-22-
108'~09~
of hydroquinone was added and the product was distilled
through a Vigreux column to give 431 grams of product having
a boiling point of 770 C/1.4 mm, n20 = 1.4848. The monomer was
then passed through a column of activated sodium aluminum -
silicate.
To prepare the polymer, there were refluxed in a 75C
bath for 4 hours 50 g of 5-norbornene-2-ylmethyl methacrylate
(free of inhibitors), 100 ml acetone, 100 ml benzene, and
0.5 gram 2,2'-azobis(2-methylpropionitrile) (AIBN). The
reaction mixture was blended with methanol and the solid
polymer which had formed was filtered, washed with methanol,
and dried in a vacuum at 35~C. The yield was 36.3 g (72.6%),
{~} = 0.32 (benzene). The desirable range for ~ is about
0.2 to 1). This polymer was readily soluble in 100% benzyl
alcohol. The polymer had an absorption band in the ultraviolet
at 208 nm.
The fact that the double bond in the ring of Polymer N
is very reactive has been utilized in four ways in this ~ -
invention to convert Polymer N to crosslinked compositions
which are insoluble in aromatic alcohols. There have been
used: (1) energy in the form of heat or light; (2) peroxides
or other radical sources as crosslinking initiators; (3) mono-
mercaptans containing functional groups capable of forming
hydrogen bonds as crosslinking agents; and t4) bismercaptans
as crosslinking agents. ~-
The mechanism of crossIinking by heat or light
is not certain, but it is hypothesized that radical sources -
give free radicals which add to the double bond of the ring
givlng new free radicals which undergo interchain combinations.
Mercaptans add extremely rapidly to the norbornene double
bond via a radical chain reaction. If, e.g., mercaptoacetic
acid is used, a -SCH2C02H substituent is introduced and
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~08Z~90
crosslinking via interchain hydrogen bonding occurs. Bis-
mercaptans give, via interchain additions, covalently crosslinked
products.
Examples 20 to 27
Laboratory examples Or ~or~ing crosslinked materials
and testing their resistance to solution in aromatic alcohols
follow. The general procedure was to dissolve treated or
untreated Polymer N in methylene chloride (5 ml per gram)
and cast a rilm on a glass slide. For the mercaptan addition,
10 a stoichiometric amount of mercaptan was added to the methylene
chloride solution immediately before casting a film. The
other treatments were done after casting the film.
One half of the slide bearing the film was immersed in
100% benzyl alcohol for one hour, then dried in a vacuum at
100C for one hour, and the two halves of the slide compared
to ascertain the action of the benzyl alcohol. Benzyl alcohol
was used as a conveniently available representative of -
aromatic alcohols. The results appear in Table III below for
Examples 20 to 27: -
Table III
Example Treatment of Polymer N Action in 100% Benzyl Alcohol
Heat at 190C ror 60 sec. Insoluble; swells
21 H1gh pressure Hg lamp, Insoluble; swells
30 sec. (a)
22 Xenon flash, 9.9 kv.g Insoluble; swells
50 usec.
23 Heat 60 sec. at 190C with Insoluble; swells
25 mole % dl-t-butyl peroxlde
24 Heat 60 sec. at 190C wlth Insoluble; swells
25 mole % AIBN
Heat 60 sec. at 190C with Insoluble; not swollen
25 mole % benzoyl peroxide
26 React with mercaptoacetic Insoluble; swells
acid (HSCH2C02H) (b)
-7 React with 1,3-dimercapto-2- Insoluble; not swollen
propanol (HSCH2CHOHCH2SH) (c)
-24-
1(~8;~090
100% poly(5-norbornene-2-ylmethyl methacrylate)
(a) A 30 min. exposure to "black light" W caused no reaction.
(b) The same result was obtained with mercaptopropionic acid
(HSCH2CH2C02H), 2-mercaptoethanol (HSCH2CH20H), and
3-mercapto-2-hydroxy propanol (HSCH2CHOHCH20H).
(c) 1,2-dimercaptoethane (HSCH CH2SH), 1,5-dimercapto-3-oxa-
pentane (HSCH2CH2eCH2CH2SH~,and 1,5-dimercapto-3-thiapentane
(HSCH2CH2SCH2CH2SH) reacted similarly.
All the above compositions are suitable because of
their insolubility in the aromatic alcohol. The fact that
there was swelling in some examples is not significant
because the tests were run in 100% benzyl alcohol rather ~ -
than the much lower concentration to be expected in photo-
graphic processing solutions. I
Examples of the application of the above reactions
to the fabrication of pods follow. The sealant was machine
coated along one long edge of the blank as shown at 22 in
Fig. 2 at a level of 160 mg/ft2 using a 4% by weight solids
solution in methylene chloride treated and then formed into
a pod.
It is an important and unexpected finding that the reaction
of Polymer N with mercaptans is concentration dependent with
respect to Polymer N. When, for example, a stoichiometric
amount of HSCH2CHOHCH2SH was added to Polymer N
dissolved in CH2C12 (1 gram per 5 ml CH2C12 or 16.7% solids
by weight), gelation occurred in 30 min. When the same
bismercaptan was added to a 4% by weight solids solution no
gelation was observed after several days. For best results
without detrimental gelation it is preferred that
the solution contain no more than 10% solids, desirably
1-10% by weight.
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I
,' : '
1082090
Example 28 - Action of Heat
-
After coating the non-crosslinked Polymer N as described
above, and forming a simulated pod weak seal, the weak
seal had a burst strength Or only 0.24 lbs/in. at the highest
seal forming temperature. However, after keeping for three
days at 145F. ~63C), strength increased due to crosslinking
in situ, and was 0.32 lbs/in. for a seal which had been
formed at 275F (135C) and 0.47 lbs/in. for a seal formed
at 325F (163C).
10 Example 29 - Action Or Heat
A pod weak seal formed as in Example 28 was heated for
5 minutes at 200C. The burst strength was increased to
0.34 lbs/in. and 0.54 lbs/in. for seals formed at 300F (149C)
and 375F (190C), respectively.
Example 30 - Resistance to Benzyl Alcohol
.
The described sealant crosslinked Polymer N, was coated
and sealed at 300F (149C). After two weeks in contact with
a formulation containing 4% benzyl alcohol, the burst strength
was only 0.52 lbs/in., showing that the benzyl alcohol had
20 not dissolved the seal, and thus had not permitted the
poly(vinyl chloride) coatings to seal together.
Example 31 - Xenon Flash Treat_ent
The burst strength of the seal of Example 28, formed I -
at 325F (163C), was increased from 0.24 lbs/in to 0.40 lbs/in
by xenon flashing of Polymer N.
Example 32 - Treatment with Di-t-butyl peroxide
. . _
Polymer N plus 25 mole percent di-t-butyl peroxide
was coated. After keeping at 145F (63C) for 3 days to
promote a crosslinklng reaction the sealing latitude was
30 very good, being 0.35 lbs/in. burst strength for a seal formed
-26-
-
-, ' ' .: ' . '
1~)8~090
at 250F (121C) and o.63 lbs/in. for a seal formed at 325F
(163C). By sealing latitude is meant the temperature range
over which satisfactory burst strengths are achieved.
Example 33 - Treatment with Benzoyl Peroxide
Polymer N crosslinked with 25 mole percent benzoyl
peroxide was coated, sealed, and kept three days at 145F
(63C). The sealing latitude was from 0.45 lbs/in. burst
strength for a seal formed at 225F (107C) to 0.60 lbs/in.
for a seal formed at 300F (149C).
A second sample was sealed at 375F (190C) and stored
in contact with a photographic formulation containing
2% benzyl alcohol. After two weeks, burst strength was , -
0.33 lbs/in. and had remained constant.
Example 34 - Treatment with 2,2lazobis(2-methylpropionitrile)
Polymer N crosslinked with 25 mole percent AIBN was coated,
sealed, and incubated for three days at 145F (63C). ¦
Sealing latitude was from 0.40 lbs/in burst strength ~or a seal
formed at 225F (107C) to 0.73 lbs/in. for a seal formed at
300F (14~C).
Example 35 - Treatment with Mercaptoacetic Acid
-
To a 4% solids solution of Polymer N in CH2C12 was added
HSCH2C02H (0.48 gram per gram of Polymer N - a stoichiometric
amount). After edge coating, the pods were sealed and
incubated for three days at 145F (63C) and had the following ll
sealing latitude: 0.30 lbs/in. burst strength for a seal ' -
formed at 250F (121C) to 0.44 lbs/in. for a seal formed
at 325F (163C). The formulation within the pod contained
one percent benzyl alcohol.
-27-
.
`~
1~8ZO9O
.
Example 36 - Treatment with 1,3-dimercapto-2-propanol
A 4% solids solution in CH2C12 of Polymer N was treated
with 0.323 g. of HSCH2CHOHCH2SH Per gram of Polymer N
(stoichiometric amounts). After sealing and keeping at 145F
(63C) for three days the latitude was from 0.31 lbs/in
burst strength rOr a seal formed at 275F (135C) to 0.50 lbs/in.
for a seal formed at 325F (163C).
In another experiment, the pods were sealed after coating
at 350F (177C) and left in contac~ with formulation
containing 4% benzyl alcohol for two weeks, during which
the burst strength ehanged from an initial value Or 0,32
lbs/in. to 0.25 lb/in., showing that the seal had resisted
solution in the benzyl alcohol. ¦ -
All the simulated and actual pod seals of Examples
28 to 36 were found not to increase in their burst strengths
to an undesirable extent when subjected to the action of
benzyl alcohol.
In contrast to the above examples, seals formed with
poly(2-norbornylmethyl methacrylate) described in Research
Disclosure for November 1974, and left in contact with a
formulation containing 2% benzyl alcohol, increased in burst
strength from 0.30 lbs/in. to 0.90 lbs/in. in two weeks,
an undesirable increase.
Seal burst strengths in the above examples were all
determined in an Instron Tensile testing machine. For burst
strength, a 1/2 inch wide strip was cut out perpendicularly
to the weak seal. The parts of the strip on opposite sides ¦~
of the seal were placed in separate ~aws of the Instron
tensile tester machine, which were then pulled apart until
the seal peeled open. The force in pounds was multiplied by
2 to obtain the value in lbs/in. '~
-28-
!~-- -
.
