Compositions: coating or plastic – Coating or plastic compositions – Carbohydrate or derivative containing
Reexamination Certificate
1999-02-16
2001-02-20
Brunsman, David (Department: 1755)
Compositions: coating or plastic
Coating or plastic compositions
Carbohydrate or derivative containing
Reexamination Certificate
active
06190446
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a new composition intended for splicing photographic films, and especially for splicing films having a cellulose triacetate support.
BACKGROUND OF THE INVENTION
In cinematography, it is common practice to join film sections by splicing. During cinematographic shooting a series of scenes is filmed onto the same negative film. From this negative film, a positive film is printed that allows these various scenes to be viewed and those that will make up the final cinematographic work to be selected. When this selection has been made, the final version of the cinematographic work is produced by cutting and splicing together the negative film according to the selected scenes.
In the first place, the negative film is cut. This cut can be done using a straight cutter which at the same time removes the emulsion layers from the part of the film to be spliced. It can also be done using a chamfer cutter, which chamfers the ends of the films to be spliced in a complementary way. Then this part of the film is glued, and this glued part is assembled with the end of the film to be spliced by maintaining pressure until the films are finally spliced. To increase the speed of splicing, a splicing technique called “hot splicing” consists in carrying out the splice at temperatures that can reach 50° C.
This splicing is especially tricky to use because the negative film resulting from the splicing of the film parts is the base film that will be used to produce copies for projection on a film screen. Thus the splices must be solid to withstand the mechanical stresses that the film is subjected to when printing the copies. Further these splices must withstand cleaning of the film in solvents. After splicing the film, it is essential to remove the traces of the glue remaining on the film. Finally, these splices must not be photographically visible because they would be reproduced on the copies obtained from this film.
Glues containing nitrocellulose in solution in a mixture of organic solvents are known for splicing photographic films. These glues contain solvents of the dioxane and/or dichloromethane or dichloroethane type in substantial quantities. For safety and environmental reasons, it is desirable to use glues that do not contain these organic solvents; in particular in the hot treatment processes that help these solvents to evaporate. It is particularly desirable to have a glue that does not contain dioxane.
SUMMARY OF THE INVENTION
The present invention provides a glue for splicing photographic films that comprises:
0.5 to 4% nitrocellulose,
5 to 25% of alkanol
5 to 20% lower alkyl acetate,
20 to 80% ketone, and
4 to 15% alkoxyalcohol.
In the scope of the invention, lower alkyl means alkyl groups containing 1 to 4 carbon atoms.
The invention also relates to a process a first and a second photographic films, each film comprising a support and a silver halide emulsion layer, process that comprises:
(a) removing the emulsion layer from an end of the first film,
(b) applying a glue as defined in claim
1
to said end, and
(c) contacting said end with the end of the second film for slicing the films.
Another process of the invention relates to a process for splicing a first and a second photographic films, each film comprising a support and a silver halide emulsion layer, process that comprises:
(a) chamfering the end of the first and the second films so that the end of one film is complementary to the end of the other film removing the emulsion layer from an end of the first film,
(b) applying a glue as defined in claim
1
to said end, and
(c) contacting said end with the end of the second film for slicing the films.
This glue is particularly efficient for cold splicing of photographic films comprising cellulose triacetate support.
DETAILED DESCRIPTION OF THE INVENTION
According to an embodiment of the invention, alkanol is preferably a lower alkanol comprising 1 to 4 carbon atoms.
According to a preferred embodiment, the glue comprises at least one lower alkanol selected from among methanol, ethanol, propanol, alone or in combination.
According to a particular embodiment, the glue of the invention comprises in combination of methanol and ethanol, ethanol being less than 10% by weight of the combination of methanol and ethanol.
The lower alkyl acetate useful in the invention can be ethyl acetate, butyl acetate, and propyl acetate, preferably butyl acetate, alone or in combination.
The alkoxy alcohol useful in the glue of the invention is preferably ethylene glycol monoalkylether such as ethylene glycol monopropylether.
The ketone of the present invention can be acetone, or methylethylketone, preferably acetone.
According to preferred embodiments, the glue consists essentially of from 0.5 to 4% nitrocellulose, 5 to 25% of alkanol, 5 to 20% lower alkyl acetate, 40 to 80% ketone, and 4 to 15% alkoxyalcohol.
According to one particular embodiment, the glue comprises 0.5 to 2% nitrocellulose, 5 to 20% alkanol, 10 to 20% lower alkyl acetate, 60 to 70% acetone and 4 to 15% ethylene glycol monopropylether.
According to another particular embodiment, the glue comprises 1.5 to 1.8% nitrocellulose, 6 to 10% methanol, 0.2 to 1% ethanol, 15 to 20% butyl acetate, 60 to 70% acetone, and 8 to 12% ethylene glycol monopropylether.
The splicing process of the invention can be used with photographic films cut with a straight cutter, for example a Hamman straight cutter or a Bell Howell straight cutter.
The splicing process of the invention can be carried out from photographic films having chamfering ends, for example with a Hamman chamfer cutter.
The glue of the present invention is useful for splicing color or black and white photographic films comprising light sensitive silver halide grains. Such film can be Eastman Color Positive® film, Eastman Color Negative® film, Eastman Color Intermediate® film, reversal films, Kodachrome® films, or Ektachrome® films. The glue of the present invention is especially useful for splicing motion picture films.
The glue of the present invention is particularly efficient for splicing photographic films whose support is cellulose triacetate.
The present invention is described in more detail in the following examples.
REFERENCES:
patent: 1987570 (1935-01-01), Bruson
patent: 2037053 (1936-04-01), Snyder et al.
patent: 2169199 (1939-08-01), Thomas
patent: 2296891 (1942-09-01), Andersen
patent: 2510166 (1950-06-01), Baruch et al.
patent: 2895844 (1959-07-01), Bader et al.
patent: 4483714 (1984-11-01), Yamaue et al.
patent: 1 352 605 (1974-05-01), None
patent: 1527596 (1978-10-01), None
Paul Ann-Christin
Paul Swaraj
Anderson Andrew J.
Brunsman David
Eastman Kodak Company
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