CA1194737A - Safe light paper for photographic films - Google Patents
Safe light paper for photographic filmsInfo
- Publication number
- CA1194737A CA1194737A CA000406765A CA406765A CA1194737A CA 1194737 A CA1194737 A CA 1194737A CA 000406765 A CA000406765 A CA 000406765A CA 406765 A CA406765 A CA 406765A CA 1194737 A CA1194737 A CA 1194737A
- Authority
- CA
- Canada
- Prior art keywords
- paper
- safe light
- layer
- thickness
- polyolefin
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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Classifications
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
- G03C3/00—Packages of films for inserting into cameras, e.g. roll-films, film-packs; Wrapping materials for light-sensitive plates, films or papers, e.g. materials characterised by the use of special dyes, printing inks, adhesives
- G03C3/02—Photographic roll-films with paper strips
Landscapes
- Engineering & Computer Science (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Paper (AREA)
- Laminated Bodies (AREA)
- Silver Salt Photography Or Processing Solution Therefor (AREA)
- Manufacture Of Macromolecular Shaped Articles (AREA)
Abstract
Safe light papers for photographic films ABSTRACT OF THE DISCLOSURE
The safe light paper comprises a paper sup-port having its surface covered on one or both sides with a layer which is formed from a dried dispersion of one or more polyolefins in water or an organic li-quid. Safe light papers furnished in such a manner are distinguished by the economical means by which they may be produced by remarkable mechanical properties and an excellent resistance to tropical conditions.
The safe light paper comprises a paper sup-port having its surface covered on one or both sides with a layer which is formed from a dried dispersion of one or more polyolefins in water or an organic li-quid. Safe light papers furnished in such a manner are distinguished by the economical means by which they may be produced by remarkable mechanical properties and an excellent resistance to tropical conditions.
Description
L?~
Safe light paper for photographic films This invention relates to a safe light paper designed to protect light-sensitive film material against the acti~n of light and to ensure smooth trans-port of the film material inside the camera.
Safe light paper generally consists of an opaque paper support which is generally coloured and is marked with signs or letters (the so-called "signature print") on one side.
The safe light paper may be coated to improve its protection against light, to prevent the film material being photographically affected by the paper or by the printing ink used for the signature print, or to prevent the paper from sticking to the light-sensitive photo-graphic layers of the film or to the gelatine-containing backing.
It is known to provide safe light paper with polyethylene layers. However, such coatings or combinations which are produced by extrusion or by laminating have serious disadvantages. For technological reasons, it is impossible to produce layers having a thickness of less than about 20 ~m. The thickness of the raw paper must therefore be reduced accordingly so that the safe light paper will not exceed the final overall thickness laid down for its particular purpose.
Since the polyethylene coating does not make any contribution to the mechanical strength proportional to its thickness, the application of the coating is accompanied by a reductio'n in mechanical strength which is largely proportional to its contribution to the overall thickness of the safe light paper. This reduction in mechanical strength finally interferes with satisfactory processing of the safe light paper or with the use o~ film materialcontaining such paper inslde the camera. Extrusion coating and laminating are, moreover, technologically complicated processes.
~L9'~737 A light sealing protective strip for roll ~ilms disclosed in German Auslegeschrift No. 1,036,050 is composed of two thin foils stuck together, one of which is made of an opaque plastics material and the other of a transparent plastics material. A layer of pigment and the so-called signature print are applied between the two foils or on the inside of one of the two foils. The foils are bonded together either thermoplastically or by means of an adhesive. The opaque foil may also be pigmented paper. The production of such protective strips is relatively complicated on account of the bond-ing technique required.
A safe light paper consisting of a kraft paper coated by extrusion with a polyethylene containing carbon black has been disclosed in French Patent No. 1,449,852~
The polyethylene layer produced in this manner contributes at least 20 ~m to the thickness of the safe light paper.
A safe liyht paper in which a layer of a styrene-butadiene copolymer blackened with carbon black is applied to a paper support and covered with a layer of carbon black and polyethylene or polypropylene has been disclosed in U.S. Patent No, T 871,004. The upper layer may be applied to the polymer layer below it by the conventional methods, e.g. by melt extrusion or by application from an ~ 25 aqueous dispersion. In the latter case, the lower layer is exposed to corona irradiation to improve its adhesiveness before it is coated. Preparation of the upper layer by melt extrusion entails the above disadvantages while application of the upper layer from an aqueous dispersion requires the use of corona irradiation and thus consider-able additional technical expenditure.
Safe light papers produced by coating a paper support with a mixture of an ethylene~vinyl acetate copolymer and carbon blac~ in toluene has been described in German ~ffenlegungsschrift No~ 1,903,378~ However, safe light paper provided with such substances are insufficiently resistant to tropical conditions. They have a marked tendency to tackiness at high atmospheric humidity levels.
It is an object of the present invention to provide a safe light paper which may be produced economically and by a technically simple process and which, while having a low overall thickness, provides the protection against light and has the mechanical characteristics necessary for a safe light paper used for photographic roll films.
According to the present invention there is provided safe light paper containing a paper support coated on one or both sides of its surface with a layer formed from a polyolefin or a polyolefin mixture, characterised in that the layer is formed from the dried dispersion of one or more polyolefins in ~ater or in an organic liquid and in that the thickness of the polyolefin layer is from 1 -to 20 ~um, wherein the quantity of dry substance applied is from 1 to 20 g/m .
Suitable layer-forming polyolefins are based on C2-C4 alkenes. Examples include polyethylene, polypropylene, poly-butylene and polyisobu-tylene. Polyethylene and polypropylene are preferred.
The polyolefins are applied as dispersions in ~ater or in an organic liquid to the surface of an optionally coloured or hlackened paper ~hich may in addition carry markings and letters, and the layer is dried.
Dispersions of the above-mentioned polyolefins in ~ater or organic liquids suitable for the treatment of the safe '~'' 3'~
light papers according to the present invention are available commercially. Aqueous polyolefin dispersions are sold having solid contents of ca. 40%, by weight. The size of the dispersed particles is from 0.1 to 0.2 ,um. The dispersions may be diluted with water and are miscible with each other.
Polyolefin dispersions in organic liquids are also available commercially. Examples include dispersions of poly-ethylene in xylene, ethanol, butanol, butyl glycol or ~19~
similar organic solvents. The particle sizes range from 0.5 to lO ~m and the solid contents from 20 to 25~, by weight.
As indicated a~ove~ the polyolefin dispersions may be prepared either in water or in organic liquids.
Suitable dispersions may be obtained r for example~
by the emulsion polymerisation of olefins or by dispersion of suitably micronized polymers in the appropriate medium.
Although dispersions in organic media may advantageously - be used under certain technical conditions, aqueous dispersions are to be preferred for economical and `` ecological reasons.
The quantity of dispersions or polyolefins to be applied may be adapted to the particular requirements.
The quantity of dry substance applied may be from l to 20 g/m . Applications offrom 3 to lO g/m are preferred.
The thickness of the dry coating should be from l to 20 ~m, preferably from 3 to lO ym.
Substances, such as pigments, dyes~ matting agents and others, may be applied to the paper support together with the dispersions to influence the optical or mechanical properties of the safe light paper as desired.
In order to ensure, however, that the properties of the polymers will not be deleteriously affected, the quantities of these additives should not exceed from ca.
20 to 30~, by weight r based on the dry quantity of polymer applied.
The safe light papers according to the present invention may be coated with the polyolefin layer on one or both sides~ Any of the conventional methods are suitable for application of the dispersions, e.g.
immersion, roller application using smooth or rastered rollers, air caating knives or doctor coatersO The raw paper may be coated either immediately or after printing.
In the former case~ the coating is is most suitably applied by the paper manufacturer in the sizing press or the coating machine~ In the latter case, application of the coating is most economically carried out in the same step as application of the signature print. The layers may be dried by known methods, e.g. hot air, infra-red radiators, heating rollers or the like.
So-called "Kraft paper'' is particularly suitable as paper support although other types of paper having the necessary physical strength may, of course, also be used.
The weight of the raw paper should be from 40 to lO0 g/m2.
Raw paper of this weight has the necessary mechanical strength, as well as elasticity for the given purpose.
The paper may contain carbon black or it may be b~ackened on one side to provide the necessary protection against light. The paper may also be printed with signs or consecutive numbers to indicate the print number in the conventional manner.
The safe light papers provided with polyolefin layers in accordance with the present invention are found to be superior in a suprising manner to the known safe light papers having polyolefin layers applied by extrusion or laminating. The polyolefin layers may be kept much thinner so that correspondingly greater mechanical strength may be obtained for a given overall thickness of safe light paper, which is mainly determined by the quality and thickness of the paper itself. In addi-tion, the safe light papers according to the present invention are distinguished by the simple and economical means by which they may be produced and by the excellent resistance thereof to tropical conditions.
It was also not to be expected that the anti-adhesive properties of extruded or laminated polyolefin layers would be preserved inspite of the fact that polyolefin dispersions as a rule contain dispersing agents which generally do not have anti-adhesive charac-teristics.
It may therefore be assumed that these dispersing agents to a large extent diffuse into the paper so that only residues o~ the dispersing agent are left in the surface of the layer after the drying process.
To test the tendency of the paper to stick, safe light paper and photographic filmt both 60 mm in widthr are rolled by hand on a roll film spool 120 under applica-tion of a pressure of 500 p. The spool is then kept in an air conditioned chamber for 7 days at 35C and 90%
relative humidity. The tendency of the two components to stick together is assessed in terms o the quanti~y of paper fibre transferred to the film after separation of the film and paper. In the assessment, l = no paper fibres detected, 6 = film and safe light paper completely stuck together; intermediate stages assessed accordingly.
The thickness of the paper is measured according to DIN 53 lll, using a measuring instrument which has a measuring surface of 2 cm with a surface pressure of l kp~cm2. The mechanical strength is determined on a commercial tearing machine. The width of the sample strip is 15 mm and the length clamped into the machine is 180mm. The test environment is 23C, 50% relative humidity. The samples are kept under the same conditions for 24 hours before the test is carried out. The breaking load found is used as a direct measure of the mechanical strength.
The following Examples illustrate the present invention.
Example l Sample A, Uncoated Kraft paper 90 ~m in thickness, filled with carbon black~ The properties tested were the mechanical strength and the tendency to stick against the NC layer on the back of a roll film 120 Samp~e B
A 40% r by weight, aqueous polyethylene dispersion was applied to a raw paper similar to that of Sample A by 73~
the roller application process at the rate of 30 m/min and the paper was dried by air at 60C. The applicator was adjusted so that the dry weight of layer applied was 10 g/m2. The thickness of the coated paper was then 100 lum and that of the coating ca. 10 ~m. The properties tested were the mechanical strength and the tendency to stick; the latter was tested by bringing the back of the roll film into contact with the coated side of the paper.
Sample C.
A Kraft paper 60 ~m in thickness filled with carbon black was coated with 40 ,um of polyethylene by extrusion and tested in the same manner as Sample B.
Sample Thickness Breaking Load Tendency to stick against NC layer A 90 ,um 11.6 kp 5 - 6 B 100 Jum 11.8 kp C 100 jum 8.2 kp Example 2 Sample A.
Uncoated Kraft paper 95 ~m in thickness filled with carbon black.
Sample B.
A 20~, by weight, aqueous polyethylene dispersion was applied to raw paper similar to that of Sample A at the rate of 25 m/min by the immersion process, fol]owed by blowing off with airbrush. The airbrush was adjusted so that the solids content applied amounted to 6 g/m and the layer had a thickness of ca~ 5 ~m. The total thickness of the coated paper was then lQ0 ~m.
Sample C~
A Kraft paper 75 ~m in thickness and filled with carbon black was coated with a 25 ~m thick layer of polyethylene by the extrusion process.
7a~ 7 Sample Thickness Breaking Load Tendency to stick against NC layer.
A 95 ~m 12.3 kp 4 B 100 ~m 12.5 kp C 100 lum 9.8 kp The results of Examples 1 and 2 show a clear superiority in mechanieal strength Gf the safe light papers according to the present invention compared with comparable known safe light papers.
Example 3 A Kraft paper 95 ~um in thickness and filled with carbon black was coated as in Example 2, sample B, but with a substance having the following composition:
500 ml of a 40%, by weight, polyethylene dispersion in water, 130 ml of a 30%, by weight, dispersion of carbon black in water; and 370 ml of water.
The quantity applied was adjusted to produce a dry layer thickness of 5 -~m. The following res~llts were obtained when the total thickness of the coated paper was 100 ~m:
~reaking load 12.5 kp Tendency to stick against NC
layer 1 - 2.
This Example shows that the addition of a pigment to the polyethylene layer does not impair the mechanical strength of the safe light paper according to the present invention and does not increase the tendeney thereof to stick~
73t7 g Example 4 Sample A~
A Kraft paper filled with carbon black and 80 ~m in thickness was printed with signs to indicate the image numbers for llO cassette packs. The properties tested were the mechanical strength and the tendency of the printed side to stick against the emulsion layer of a colour negative film.
Sample ~.
A 15~, by weight, polyethylene dispersion was applied to the printed side of a paper similar to that of Sample A by the roller application process so that the coating amounted to caO 3 g/m and had a thickness of ca. 3 ~m. The test was carried out as for Sample A.
Sample C.
A Kraft paper 60 ~m in thickness and filled with carbon black was printed with signs to indicate the image numbers for a llO cassette pack and then coated with a 23 pm thick layer of polyethylene by the extrusion process. The test was carried out as for Sample A.
Sample Thickness Breaking Load Tendency to stick against emulsion layer A 80 ~mlO.4 kp 5 B 83 )um15 kp l -C 83 jum8.0 kp It will be seen that a safe light paper according to the present invention has a greater mechanical strength for a given overall thickness and resistance to tropical conditions than a paper carrying an extruded polyethylene layer~
Example 5 A Kraft paper 80 ~m in thickness filled with 3 ~
carbon black was coated on the printed side with a l5~, by wei~ht, solution of an ethylene/vinyl acetate co-polymer in toluene by the roller application process to form a coating amounting to 3 g/m2~
The tenaency of the resulting material to stick was tested as described for Sample A in Example 4, a~d the value ~ was obtained. The safe light paper is therefore unsuitable for use at high atmospheric moisture levels.
Example 6 Example 2 was repeated, using a polyethylene dispersion in an organic medium.
Sample A.
Uncoated Kraft paper filled with carbon black, thickness 95 ~Im.
Sample B.
Kraft paper similar to that of Sample A, coated on one side with a 20~, by weight, polyethylene dispersion in n-butanol, application 6 g/m2, layer thickness 5 ~mO
Sample C.
Kraft paper filled with carbon black, thickness 75 um, coated with polyethylene on one side by the extrusion process, layer thickness 25 um.
The test results correspond to those of Example
Safe light paper for photographic films This invention relates to a safe light paper designed to protect light-sensitive film material against the acti~n of light and to ensure smooth trans-port of the film material inside the camera.
Safe light paper generally consists of an opaque paper support which is generally coloured and is marked with signs or letters (the so-called "signature print") on one side.
The safe light paper may be coated to improve its protection against light, to prevent the film material being photographically affected by the paper or by the printing ink used for the signature print, or to prevent the paper from sticking to the light-sensitive photo-graphic layers of the film or to the gelatine-containing backing.
It is known to provide safe light paper with polyethylene layers. However, such coatings or combinations which are produced by extrusion or by laminating have serious disadvantages. For technological reasons, it is impossible to produce layers having a thickness of less than about 20 ~m. The thickness of the raw paper must therefore be reduced accordingly so that the safe light paper will not exceed the final overall thickness laid down for its particular purpose.
Since the polyethylene coating does not make any contribution to the mechanical strength proportional to its thickness, the application of the coating is accompanied by a reductio'n in mechanical strength which is largely proportional to its contribution to the overall thickness of the safe light paper. This reduction in mechanical strength finally interferes with satisfactory processing of the safe light paper or with the use o~ film materialcontaining such paper inslde the camera. Extrusion coating and laminating are, moreover, technologically complicated processes.
~L9'~737 A light sealing protective strip for roll ~ilms disclosed in German Auslegeschrift No. 1,036,050 is composed of two thin foils stuck together, one of which is made of an opaque plastics material and the other of a transparent plastics material. A layer of pigment and the so-called signature print are applied between the two foils or on the inside of one of the two foils. The foils are bonded together either thermoplastically or by means of an adhesive. The opaque foil may also be pigmented paper. The production of such protective strips is relatively complicated on account of the bond-ing technique required.
A safe light paper consisting of a kraft paper coated by extrusion with a polyethylene containing carbon black has been disclosed in French Patent No. 1,449,852~
The polyethylene layer produced in this manner contributes at least 20 ~m to the thickness of the safe light paper.
A safe liyht paper in which a layer of a styrene-butadiene copolymer blackened with carbon black is applied to a paper support and covered with a layer of carbon black and polyethylene or polypropylene has been disclosed in U.S. Patent No, T 871,004. The upper layer may be applied to the polymer layer below it by the conventional methods, e.g. by melt extrusion or by application from an ~ 25 aqueous dispersion. In the latter case, the lower layer is exposed to corona irradiation to improve its adhesiveness before it is coated. Preparation of the upper layer by melt extrusion entails the above disadvantages while application of the upper layer from an aqueous dispersion requires the use of corona irradiation and thus consider-able additional technical expenditure.
Safe light papers produced by coating a paper support with a mixture of an ethylene~vinyl acetate copolymer and carbon blac~ in toluene has been described in German ~ffenlegungsschrift No~ 1,903,378~ However, safe light paper provided with such substances are insufficiently resistant to tropical conditions. They have a marked tendency to tackiness at high atmospheric humidity levels.
It is an object of the present invention to provide a safe light paper which may be produced economically and by a technically simple process and which, while having a low overall thickness, provides the protection against light and has the mechanical characteristics necessary for a safe light paper used for photographic roll films.
According to the present invention there is provided safe light paper containing a paper support coated on one or both sides of its surface with a layer formed from a polyolefin or a polyolefin mixture, characterised in that the layer is formed from the dried dispersion of one or more polyolefins in ~ater or in an organic liquid and in that the thickness of the polyolefin layer is from 1 -to 20 ~um, wherein the quantity of dry substance applied is from 1 to 20 g/m .
Suitable layer-forming polyolefins are based on C2-C4 alkenes. Examples include polyethylene, polypropylene, poly-butylene and polyisobu-tylene. Polyethylene and polypropylene are preferred.
The polyolefins are applied as dispersions in ~ater or in an organic liquid to the surface of an optionally coloured or hlackened paper ~hich may in addition carry markings and letters, and the layer is dried.
Dispersions of the above-mentioned polyolefins in ~ater or organic liquids suitable for the treatment of the safe '~'' 3'~
light papers according to the present invention are available commercially. Aqueous polyolefin dispersions are sold having solid contents of ca. 40%, by weight. The size of the dispersed particles is from 0.1 to 0.2 ,um. The dispersions may be diluted with water and are miscible with each other.
Polyolefin dispersions in organic liquids are also available commercially. Examples include dispersions of poly-ethylene in xylene, ethanol, butanol, butyl glycol or ~19~
similar organic solvents. The particle sizes range from 0.5 to lO ~m and the solid contents from 20 to 25~, by weight.
As indicated a~ove~ the polyolefin dispersions may be prepared either in water or in organic liquids.
Suitable dispersions may be obtained r for example~
by the emulsion polymerisation of olefins or by dispersion of suitably micronized polymers in the appropriate medium.
Although dispersions in organic media may advantageously - be used under certain technical conditions, aqueous dispersions are to be preferred for economical and `` ecological reasons.
The quantity of dispersions or polyolefins to be applied may be adapted to the particular requirements.
The quantity of dry substance applied may be from l to 20 g/m . Applications offrom 3 to lO g/m are preferred.
The thickness of the dry coating should be from l to 20 ~m, preferably from 3 to lO ym.
Substances, such as pigments, dyes~ matting agents and others, may be applied to the paper support together with the dispersions to influence the optical or mechanical properties of the safe light paper as desired.
In order to ensure, however, that the properties of the polymers will not be deleteriously affected, the quantities of these additives should not exceed from ca.
20 to 30~, by weight r based on the dry quantity of polymer applied.
The safe light papers according to the present invention may be coated with the polyolefin layer on one or both sides~ Any of the conventional methods are suitable for application of the dispersions, e.g.
immersion, roller application using smooth or rastered rollers, air caating knives or doctor coatersO The raw paper may be coated either immediately or after printing.
In the former case~ the coating is is most suitably applied by the paper manufacturer in the sizing press or the coating machine~ In the latter case, application of the coating is most economically carried out in the same step as application of the signature print. The layers may be dried by known methods, e.g. hot air, infra-red radiators, heating rollers or the like.
So-called "Kraft paper'' is particularly suitable as paper support although other types of paper having the necessary physical strength may, of course, also be used.
The weight of the raw paper should be from 40 to lO0 g/m2.
Raw paper of this weight has the necessary mechanical strength, as well as elasticity for the given purpose.
The paper may contain carbon black or it may be b~ackened on one side to provide the necessary protection against light. The paper may also be printed with signs or consecutive numbers to indicate the print number in the conventional manner.
The safe light papers provided with polyolefin layers in accordance with the present invention are found to be superior in a suprising manner to the known safe light papers having polyolefin layers applied by extrusion or laminating. The polyolefin layers may be kept much thinner so that correspondingly greater mechanical strength may be obtained for a given overall thickness of safe light paper, which is mainly determined by the quality and thickness of the paper itself. In addi-tion, the safe light papers according to the present invention are distinguished by the simple and economical means by which they may be produced and by the excellent resistance thereof to tropical conditions.
It was also not to be expected that the anti-adhesive properties of extruded or laminated polyolefin layers would be preserved inspite of the fact that polyolefin dispersions as a rule contain dispersing agents which generally do not have anti-adhesive charac-teristics.
It may therefore be assumed that these dispersing agents to a large extent diffuse into the paper so that only residues o~ the dispersing agent are left in the surface of the layer after the drying process.
To test the tendency of the paper to stick, safe light paper and photographic filmt both 60 mm in widthr are rolled by hand on a roll film spool 120 under applica-tion of a pressure of 500 p. The spool is then kept in an air conditioned chamber for 7 days at 35C and 90%
relative humidity. The tendency of the two components to stick together is assessed in terms o the quanti~y of paper fibre transferred to the film after separation of the film and paper. In the assessment, l = no paper fibres detected, 6 = film and safe light paper completely stuck together; intermediate stages assessed accordingly.
The thickness of the paper is measured according to DIN 53 lll, using a measuring instrument which has a measuring surface of 2 cm with a surface pressure of l kp~cm2. The mechanical strength is determined on a commercial tearing machine. The width of the sample strip is 15 mm and the length clamped into the machine is 180mm. The test environment is 23C, 50% relative humidity. The samples are kept under the same conditions for 24 hours before the test is carried out. The breaking load found is used as a direct measure of the mechanical strength.
The following Examples illustrate the present invention.
Example l Sample A, Uncoated Kraft paper 90 ~m in thickness, filled with carbon black~ The properties tested were the mechanical strength and the tendency to stick against the NC layer on the back of a roll film 120 Samp~e B
A 40% r by weight, aqueous polyethylene dispersion was applied to a raw paper similar to that of Sample A by 73~
the roller application process at the rate of 30 m/min and the paper was dried by air at 60C. The applicator was adjusted so that the dry weight of layer applied was 10 g/m2. The thickness of the coated paper was then 100 lum and that of the coating ca. 10 ~m. The properties tested were the mechanical strength and the tendency to stick; the latter was tested by bringing the back of the roll film into contact with the coated side of the paper.
Sample C.
A Kraft paper 60 ~m in thickness filled with carbon black was coated with 40 ,um of polyethylene by extrusion and tested in the same manner as Sample B.
Sample Thickness Breaking Load Tendency to stick against NC layer A 90 ,um 11.6 kp 5 - 6 B 100 Jum 11.8 kp C 100 jum 8.2 kp Example 2 Sample A.
Uncoated Kraft paper 95 ~m in thickness filled with carbon black.
Sample B.
A 20~, by weight, aqueous polyethylene dispersion was applied to raw paper similar to that of Sample A at the rate of 25 m/min by the immersion process, fol]owed by blowing off with airbrush. The airbrush was adjusted so that the solids content applied amounted to 6 g/m and the layer had a thickness of ca~ 5 ~m. The total thickness of the coated paper was then lQ0 ~m.
Sample C~
A Kraft paper 75 ~m in thickness and filled with carbon black was coated with a 25 ~m thick layer of polyethylene by the extrusion process.
7a~ 7 Sample Thickness Breaking Load Tendency to stick against NC layer.
A 95 ~m 12.3 kp 4 B 100 ~m 12.5 kp C 100 lum 9.8 kp The results of Examples 1 and 2 show a clear superiority in mechanieal strength Gf the safe light papers according to the present invention compared with comparable known safe light papers.
Example 3 A Kraft paper 95 ~um in thickness and filled with carbon black was coated as in Example 2, sample B, but with a substance having the following composition:
500 ml of a 40%, by weight, polyethylene dispersion in water, 130 ml of a 30%, by weight, dispersion of carbon black in water; and 370 ml of water.
The quantity applied was adjusted to produce a dry layer thickness of 5 -~m. The following res~llts were obtained when the total thickness of the coated paper was 100 ~m:
~reaking load 12.5 kp Tendency to stick against NC
layer 1 - 2.
This Example shows that the addition of a pigment to the polyethylene layer does not impair the mechanical strength of the safe light paper according to the present invention and does not increase the tendeney thereof to stick~
73t7 g Example 4 Sample A~
A Kraft paper filled with carbon black and 80 ~m in thickness was printed with signs to indicate the image numbers for llO cassette packs. The properties tested were the mechanical strength and the tendency of the printed side to stick against the emulsion layer of a colour negative film.
Sample ~.
A 15~, by weight, polyethylene dispersion was applied to the printed side of a paper similar to that of Sample A by the roller application process so that the coating amounted to caO 3 g/m and had a thickness of ca. 3 ~m. The test was carried out as for Sample A.
Sample C.
A Kraft paper 60 ~m in thickness and filled with carbon black was printed with signs to indicate the image numbers for a llO cassette pack and then coated with a 23 pm thick layer of polyethylene by the extrusion process. The test was carried out as for Sample A.
Sample Thickness Breaking Load Tendency to stick against emulsion layer A 80 ~mlO.4 kp 5 B 83 )um15 kp l -C 83 jum8.0 kp It will be seen that a safe light paper according to the present invention has a greater mechanical strength for a given overall thickness and resistance to tropical conditions than a paper carrying an extruded polyethylene layer~
Example 5 A Kraft paper 80 ~m in thickness filled with 3 ~
carbon black was coated on the printed side with a l5~, by wei~ht, solution of an ethylene/vinyl acetate co-polymer in toluene by the roller application process to form a coating amounting to 3 g/m2~
The tenaency of the resulting material to stick was tested as described for Sample A in Example 4, a~d the value ~ was obtained. The safe light paper is therefore unsuitable for use at high atmospheric moisture levels.
Example 6 Example 2 was repeated, using a polyethylene dispersion in an organic medium.
Sample A.
Uncoated Kraft paper filled with carbon black, thickness 95 ~Im.
Sample B.
Kraft paper similar to that of Sample A, coated on one side with a 20~, by weight, polyethylene dispersion in n-butanol, application 6 g/m2, layer thickness 5 ~mO
Sample C.
Kraft paper filled with carbon black, thickness 75 um, coated with polyethylene on one side by the extrusion process, layer thickness 25 um.
The test results correspond to those of Example
2.
Example 7 Example 2 was repeated, but using a 20% aqueous polypropylene dispersion.
Sample A.
Uncoated Kraft paper filled with carbon black, thickness 95~um~
Sample B~
Kraft p~per similar to that of Sample A coated on one side with a 20~, by weight, aqueGus polypropylene
Example 7 Example 2 was repeated, but using a 20% aqueous polypropylene dispersion.
Sample A.
Uncoated Kraft paper filled with carbon black, thickness 95~um~
Sample B~
Kraft p~per similar to that of Sample A coated on one side with a 20~, by weight, aqueGus polypropylene
3 7 dispersion, application 6 g/m2, layer thickness 5 ~m.
Sample C.
Kraft paper filled with carbon black, thickness 75 ~m, coated with polypropylene on one side by the extrusion process, layer thickness 25 ~m.
Sample Thickness Breaking Load Tendency to stick against NC layer A 95 ~ 12.3 kp 4 - 5 B lOO u12.4 kp 2 C 100 ~ 9.6 kp 1 -The results are comparable to those of Example 2.
Sample C.
Kraft paper filled with carbon black, thickness 75 ~m, coated with polypropylene on one side by the extrusion process, layer thickness 25 ~m.
Sample Thickness Breaking Load Tendency to stick against NC layer A 95 ~ 12.3 kp 4 - 5 B lOO u12.4 kp 2 C 100 ~ 9.6 kp 1 -The results are comparable to those of Example 2.
Claims (6)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. Safe light paper containing a paper support coated on one or both sides of its surface with a layer formed from a polyolefin or a polyolefin mixture, characterised in that the layer is formed from the dried dispersion of one or more poly-olefins in water or in an organic liquid and in that the thickness of the polyolefin layer is from 1 to 20 pm, wherein the quantity of dry substance applied is from 1 to 20 g/m2.
2. Safe light paper according to Claim 1, characterised in that the polyolefin is based on a C2-C4 alkene.
3. Safe light paper according to Claim 1 or 2, char-acterised in that the layer contains not more than 30%, by weight, based on the polyolefin content, of one or more colouring agents.
4. Safe light paper according to Claim 1 or 2, char-acterised in that the layer contains not more than 30%, by weight, based on the polyolefin content, of one or more colouring agents wherein the colouring agents comprise carbon black.
5. Safe light paper according to Claim 1 or 2, char-acterised in that the layer is formed by the application of an aqueous dispersion of polyethylene or polypropylene.
6. Safe light paper according to Claim 1 or 2, char-acterised in that the layer is formed by a dispersion of poly-ethylene in n-butanol.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP3127043.3 | 1981-07-09 | ||
| DE19813127043 DE3127043A1 (en) | 1981-07-09 | 1981-07-09 | LIGHT PROTECTION PAPER FOR PHOTOGRAPHIC FILMS |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1194737A true CA1194737A (en) | 1985-10-08 |
Family
ID=6136453
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000406765A Expired CA1194737A (en) | 1981-07-09 | 1982-07-07 | Safe light paper for photographic films |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP0069927B1 (en) |
| JP (1) | JPS5817434A (en) |
| CA (1) | CA1194737A (en) |
| DE (2) | DE3127043A1 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6083939A (en) * | 1983-10-14 | 1985-05-13 | Fuji Photo Film Co Ltd | Packing material for photosensitive material |
| JPH0629955B2 (en) * | 1986-04-12 | 1994-04-20 | 富士写真フイルム株式会社 | Photosensitive material storage magazine |
| JPS63197944A (en) * | 1987-02-10 | 1988-08-16 | Konica Corp | Packaging unit for preserving quality |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| BE562856A (en) * | ||||
| GB1243783A (en) * | 1965-04-30 | 1971-08-25 | Agfa Gevaert | Wrapping paper for photographic material |
| GB1141806A (en) * | 1965-04-30 | 1969-02-05 | Agfa Gevaert Nv | Wrapping paper for photographic material |
| FR1449852A (en) * | 1965-07-07 | 1966-05-06 | Kodak Pathe | New backing paper for photographic reels |
-
1981
- 1981-07-09 DE DE19813127043 patent/DE3127043A1/en not_active Withdrawn
-
1982
- 1982-07-01 EP EP82105869A patent/EP0069927B1/en not_active Expired
- 1982-07-01 DE DE8282105869T patent/DE3267901D1/en not_active Expired
- 1982-07-07 CA CA000406765A patent/CA1194737A/en not_active Expired
- 1982-07-08 JP JP57117907A patent/JPS5817434A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5817434A (en) | 1983-02-01 |
| EP0069927B1 (en) | 1985-12-11 |
| DE3127043A1 (en) | 1983-01-20 |
| EP0069927A3 (en) | 1983-06-08 |
| EP0069927A2 (en) | 1983-01-19 |
| DE3267901D1 (en) | 1986-01-23 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |