CA1227636A - Film for thermal imaging - Google Patents
Film for thermal imagingInfo
- Publication number
- CA1227636A CA1227636A CA000458436A CA458436A CA1227636A CA 1227636 A CA1227636 A CA 1227636A CA 000458436 A CA000458436 A CA 000458436A CA 458436 A CA458436 A CA 458436A CA 1227636 A CA1227636 A CA 1227636A
- Authority
- CA
- Canada
- Prior art keywords
- film
- original
- image
- transparency
- substrate
- 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
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
- B41M5/00—Duplicating or marking methods; Sheet materials for use therein
- B41M5/26—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used
- B41M5/40—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used characterised by the base backcoat, intermediate, or covering layers, e.g. for thermal transfer dye-donor or dye-receiver sheets; Heat, radiation filtering or absorbing means or layers; combined with other image registration layers or compositions; Special originals for reproduction by thermography
- B41M5/42—Intermediate, backcoat, or covering layers
- B41M5/44—Intermediate, backcoat, or covering layers characterised by the macromolecular compounds
- B41M5/443—Silicon-containing polymers, e.g. silicones, siloxanes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
- B41M5/00—Duplicating or marking methods; Sheet materials for use therein
- B41M5/26—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used
- B41M5/40—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used characterised by the base backcoat, intermediate, or covering layers, e.g. for thermal transfer dye-donor or dye-receiver sheets; Heat, radiation filtering or absorbing means or layers; combined with other image registration layers or compositions; Special originals for reproduction by thermography
- B41M5/42—Intermediate, backcoat, or covering layers
- B41M5/426—Intermediate, backcoat, or covering layers characterised by inorganic compounds, e.g. metals, metal salts, metal complexes
Landscapes
- Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Laminated Bodies (AREA)
- Thermal Transfer Or Thermal Recording In General (AREA)
- Paints Or Removers (AREA)
- Compositions Of Macromolecular Compounds (AREA)
Abstract
Abstract This invention relates to infrared transparency films and films for thermal imaging processes, and in particular, to a coating material for such films.
Infrared imaging involves the use of a focused infrared lamp to heat an infrared absorbing image, i.e., the "original", which is in contact with a substrate, e.g., a transparency film, having thermally sensitive imaging chemicals. Upon absorbing the focused infrared light, the infrared absorbing image heats the thermally sensitive imaging chemicals on the substrate, causing a chemical reaction, resulting in a copy of the original image on the substrate.
When projection transparencies are prepared from originals which are plain paper copies prepared from electrophotographic imaging processes, localized heating of the original results in partial remelting of the toner powder thereon, causing the original to adhere to the transparency. When the original is separated from the transparency, toner powder from the original is transferred to the transparency film, resulting in partial destruction of the original and irregular black spots on the transparency.
This invention provides thermally imageable film comprising a polymeric substrate, a layer of thermally imageable material coated over at least one major surface thereof, and a release coating coated over the layer of thermally imageable material. The release coating is an organopolysiloxane applied from a composition which is curable at temperatures below about 70°C with a curing exposure time of under about 3 minutes, thereby preventing advese effects upon the layer of thermally imageable material. The release coating serves to prevent the transfer of toner powder from an original to the transparency film.
Infrared imaging involves the use of a focused infrared lamp to heat an infrared absorbing image, i.e., the "original", which is in contact with a substrate, e.g., a transparency film, having thermally sensitive imaging chemicals. Upon absorbing the focused infrared light, the infrared absorbing image heats the thermally sensitive imaging chemicals on the substrate, causing a chemical reaction, resulting in a copy of the original image on the substrate.
When projection transparencies are prepared from originals which are plain paper copies prepared from electrophotographic imaging processes, localized heating of the original results in partial remelting of the toner powder thereon, causing the original to adhere to the transparency. When the original is separated from the transparency, toner powder from the original is transferred to the transparency film, resulting in partial destruction of the original and irregular black spots on the transparency.
This invention provides thermally imageable film comprising a polymeric substrate, a layer of thermally imageable material coated over at least one major surface thereof, and a release coating coated over the layer of thermally imageable material. The release coating is an organopolysiloxane applied from a composition which is curable at temperatures below about 70°C with a curing exposure time of under about 3 minutes, thereby preventing advese effects upon the layer of thermally imageable material. The release coating serves to prevent the transfer of toner powder from an original to the transparency film.
Description
2~636 FILM FOR THERMAL IMAGING
BACKGROUND OF THE INVENTION
This invention relates to thermally image able films, and to a release coating for such films.
Infrared imaging is a form of thermal imaging that involves the use of a focused infrared lamp to heat an infrared absorbing image, commonly referred to as the "original", which image is in contact with a substrate, e.g., a transparent polymeric film, having thermally sensitive imaging chemicals applied to a major surface thereof. Upon image-wise absorbing the focused infrared radiation, the original transfers the absorbed heat to the thermally sensitive imaging chemicals on the surface of the sub-striate, thereby causing a chemical reaction which results in the formation of a copy of the image of the original on the substrate.
It is frequently desirable to prepare projection trays-pernicious, e.g. transparencies for overhead projectors, from originals which are actually plain paper copies that have previously been prepared from electrophotographic imaging processes. The electrostatic latent image on such a plain paper copy is developed I by the application and fixing of toner powder to the plain paper copy. Toner powder is generally a blend of polymer having low melting point, and carbon. When the toner on the surface of a plain paper copy in contact with the substrate from which the projection transparency is to be prepared absorbs infrared radian lion, partial remelting of the toner powder on the copy is likely to occur. The portions of the original which bear the remelted toner powder will frequently adhere to the transparency. When the original is separated from -the transparency, toner powder from .~....,.
I ho ~2~7~i36 the original is likely to be removed from said original and simultaneously transferred to the surface of the thus-formed projection transparency. This transfer of toner powder reduces the optical density of the image on the original and may, in effect, destroy the quality of the image. Thus, the original can be damaged when a projection transparency is made from it. The adherence of the toner powder to the projection transparency may also result in undesirable effects on the surface of the trays-patency itself. When the image formed on the surface of the transparency is black, the toner powder does not harm the image itself, but the powder may be rubbed off the transparency and transfer to surfaces which subsequently come in contact with the transparency. When the image formed on the transparency is a color, the toner powder can cause the colored image to have irregular black spots in the colored image area. This is considered to be a major defect in the transparency. A barrier film interposed between the image able layer of the transparency and the original can pro-vent toner powder from being picked up and retained by the trays-patency. In a type of color transparency currently in use, a film containing an acid does serve as such a barrier.
In addition to the foregoing problems, certain image able materials tend to liberate moisture upon exposure to heat or infer-red radiation. This moisture liberation results in formation of opaque areas, i.e. "halos", around the edges of the images. These areas scatter light and project as darkness around the image.
It, et at, U.S. Patent No. 3,955,035 discloses a in-alkoxy Solon coating which imparts abrasion resistance, hardness, and release properties to plastics. This coating, however, is , I.
I.
-pa- 2 I 6 557-2797 brittle and will crack if applied to a flexible polyester sub-striate of the type commonly used for preparing transparencies.
Clark, U.S. Patent No. 3,986,997 discloses a coating formed from a dispersion of colloidal silica in a condensate of methyl in-hydroxy Solon. This I..
~227~i36 coating is also brittle, and, thus, it is unsuitable for flexible sheeting. Bane, et at, United States Patent No. 4,223,072 disk closes a coating formed of phenol trihydroxy Solon. Although this coating exhibits flexibility superior to that of the coating disclosed in the Clark patent, the flexibility is insufficient to allow coating on thin polyester films. Grenoble, United States Patent No. 4,071,644 discloses a flexible sheet material coated with selections which is useful as a non-adherent surface. The coating composition in this patent comprises vinyl alkyd selection oligamers, alkyd hydrogen selections, and a catalyst. These coat-ins are curable at 250F (121C), a temperature at which a them-portray sensitive coating such as that required for infrared image able films and thermally image able films would react pro-maturely. Garden, et at, United States Patent 3,936,581 discloses a release coating containing vinyl selections in mixture with alkyd hydrogen selections and a platinum catalyst. The optimum cure temperatures are in excess of 100C, a temperature which would bring about premature reaction of the temperature sensitive coat-ins of infrared image able films.
According to the present invention there is provided a film which can be imaged by thermal energy comprising:
(a) a substrate, (b) a layer of thermally image able material coated on at least one major surface of said substrate, (c) a cured organopolysiloxane release coating, capable of releasing toner, coated over said layer of image able material, - pa - ~2~763~
said release coating being formed from a curable composition come prosing a mixture of selections consisting essential of from 0.1 to I by weight of methylhydrogenpolysiloxane and from 97 to 99.9 by weight of a selection of the formula (Shucks - x in which x has a value from 1.9 to 2 inclusive and in which silo-Jane substantially all of the molecules have attached thereto at least a total of two silicon-bonded hydroxyl groups or alkoxy groups of less than 5 carbon atoms, a catalyst, and a cross-linking agent, said curable composition being curable at a temperature under 70C. with a curing exposure time of under 3 minutes.
The preferred release coating is prepared from a compost-lion comprising (1) a curable polysiloxane, (2) a catalyst, to) a cross-linking agent, (4) a fast-cure additive, and (5) an anchorage additive.
I ~2~63~ 557-2797 The release coating composition can be applied to the imaging film by conventional means and cured at temperatures sufficiently low so as to prevent adverse effects upon the layer of image able material. The release coating is also sufficiently permeable so as to allow moisture to escape from the image able layer, thereby reducing the "halo" effect. In addition, the coating is sufficiently flexible so that the film bearing it can be imaged in commercially available infrared copying machines, e.g., EM Model 45 infrared copier. Toner powder from pie n paper copies will not stick to this coating when the imaging film is processed in a conventional thermal imaging apparatus, e.g., an infrared copier.
DETAILED DESCRIPTION
The type of film contemplated for use in the present invention is any imaging film which can be imaged by being exposed to thermal energy, e.g. infrared radiation, while in surface-to-surface contact with an original.
A particularly appropriate type of thermally image able film contemplated for use in the present invention is described in Isbrandt, et at, U.S. Patent No. 4,423,139. This film can be imaged by means of infrared radiation. This film comprises a polymeric film substrate transparent to visible light, bearing an image able layer on at least one surface thereof. Substrate materials which are suitable for this invention include polycarbon-ales, polyesters, polyacrylates, polystyrene, and polypropylene.
A preferred substrate is polyvinylidene chloride primed polyester film. The preferred polyester is polyethylene terephthalate.
I 22~763~
The image able layer comprises a nitrate salt, e.g., nickel nitrate, at least one Luke dye, e.g., 3,7-di(N,N-diethyl-amino)l0-benzoyl phenoxazine, and a binder, e.g., cellulose acetate bitterroot, one or more aromatic compounds which form quinines, dominoes, or quinonimes upon oxidation, e.g., catcall, and l-phenyl-3-pyrazolidinone or derivatives thereof. The layer can also contain a material which supplies hydrogen ions, e.g., an acidic material such as phthalic acid. Upon the application of a sufficient amount of thermal energy, the nitrate salt will oxidize the Luke dye, resulting in a change in color.
Other thermally image able films that are suitable for use in the present invention are described in Owen, U.S. Patent No.
2,910,277; Grant, U.S. Patent No. 3,080,254; and Newman et at, U.S. Patent No. 3,682,684. Owen describes a heat-sensitive chemically reactive eopy-sheet comprising a thin flexible carrier web coated with a visibly heat-sensitive coating comprising (1) a film-forming binder, (2) a noble metal salt of an organic acid, and (3) a eyelid organic reducing agent for the noble metal ions, having an active hydrogen atom attached to an atom which is select ted from the class of oxygen, nitrogen and carbon atoms and is dir-wetly attached to an atom of the cyclic ring. Grant describes a heat-sensitive copy sheet comprising the same ingredients as contained in Owen and further including a sufficient amount of phthalazine to cause observable darkening of the thermographic image. In both Owen and Grant, the preferred film-forming binder is polystyrene resin, the preferred noble metal salts of organic acid are silver Bennett and silver Stewart, and the preferred reducing agents are 3,4-dihydroxybenzoie acid and methyl gullet.
-pa- ~7~3~ 557-2797 Newman et at describes a heat-sensitive sheet material including a thin visibly heat-sensitive layer having wide exposure latitude and comprising a mixture of ferris and silver soaps of long chain fatty acids, a toner for the silver image, and a finlike kirk-lent for the soaps. An example of ferris and silver soap mixture is ferris surety and silver Bennett. An example of a toner is phthalazinone, and .
examples of finlike co-reactants for the soaps are pyrogallic acid, catcall,
BACKGROUND OF THE INVENTION
This invention relates to thermally image able films, and to a release coating for such films.
Infrared imaging is a form of thermal imaging that involves the use of a focused infrared lamp to heat an infrared absorbing image, commonly referred to as the "original", which image is in contact with a substrate, e.g., a transparent polymeric film, having thermally sensitive imaging chemicals applied to a major surface thereof. Upon image-wise absorbing the focused infrared radiation, the original transfers the absorbed heat to the thermally sensitive imaging chemicals on the surface of the sub-striate, thereby causing a chemical reaction which results in the formation of a copy of the image of the original on the substrate.
It is frequently desirable to prepare projection trays-pernicious, e.g. transparencies for overhead projectors, from originals which are actually plain paper copies that have previously been prepared from electrophotographic imaging processes. The electrostatic latent image on such a plain paper copy is developed I by the application and fixing of toner powder to the plain paper copy. Toner powder is generally a blend of polymer having low melting point, and carbon. When the toner on the surface of a plain paper copy in contact with the substrate from which the projection transparency is to be prepared absorbs infrared radian lion, partial remelting of the toner powder on the copy is likely to occur. The portions of the original which bear the remelted toner powder will frequently adhere to the transparency. When the original is separated from -the transparency, toner powder from .~....,.
I ho ~2~7~i36 the original is likely to be removed from said original and simultaneously transferred to the surface of the thus-formed projection transparency. This transfer of toner powder reduces the optical density of the image on the original and may, in effect, destroy the quality of the image. Thus, the original can be damaged when a projection transparency is made from it. The adherence of the toner powder to the projection transparency may also result in undesirable effects on the surface of the trays-patency itself. When the image formed on the surface of the transparency is black, the toner powder does not harm the image itself, but the powder may be rubbed off the transparency and transfer to surfaces which subsequently come in contact with the transparency. When the image formed on the transparency is a color, the toner powder can cause the colored image to have irregular black spots in the colored image area. This is considered to be a major defect in the transparency. A barrier film interposed between the image able layer of the transparency and the original can pro-vent toner powder from being picked up and retained by the trays-patency. In a type of color transparency currently in use, a film containing an acid does serve as such a barrier.
In addition to the foregoing problems, certain image able materials tend to liberate moisture upon exposure to heat or infer-red radiation. This moisture liberation results in formation of opaque areas, i.e. "halos", around the edges of the images. These areas scatter light and project as darkness around the image.
It, et at, U.S. Patent No. 3,955,035 discloses a in-alkoxy Solon coating which imparts abrasion resistance, hardness, and release properties to plastics. This coating, however, is , I.
I.
-pa- 2 I 6 557-2797 brittle and will crack if applied to a flexible polyester sub-striate of the type commonly used for preparing transparencies.
Clark, U.S. Patent No. 3,986,997 discloses a coating formed from a dispersion of colloidal silica in a condensate of methyl in-hydroxy Solon. This I..
~227~i36 coating is also brittle, and, thus, it is unsuitable for flexible sheeting. Bane, et at, United States Patent No. 4,223,072 disk closes a coating formed of phenol trihydroxy Solon. Although this coating exhibits flexibility superior to that of the coating disclosed in the Clark patent, the flexibility is insufficient to allow coating on thin polyester films. Grenoble, United States Patent No. 4,071,644 discloses a flexible sheet material coated with selections which is useful as a non-adherent surface. The coating composition in this patent comprises vinyl alkyd selection oligamers, alkyd hydrogen selections, and a catalyst. These coat-ins are curable at 250F (121C), a temperature at which a them-portray sensitive coating such as that required for infrared image able films and thermally image able films would react pro-maturely. Garden, et at, United States Patent 3,936,581 discloses a release coating containing vinyl selections in mixture with alkyd hydrogen selections and a platinum catalyst. The optimum cure temperatures are in excess of 100C, a temperature which would bring about premature reaction of the temperature sensitive coat-ins of infrared image able films.
According to the present invention there is provided a film which can be imaged by thermal energy comprising:
(a) a substrate, (b) a layer of thermally image able material coated on at least one major surface of said substrate, (c) a cured organopolysiloxane release coating, capable of releasing toner, coated over said layer of image able material, - pa - ~2~763~
said release coating being formed from a curable composition come prosing a mixture of selections consisting essential of from 0.1 to I by weight of methylhydrogenpolysiloxane and from 97 to 99.9 by weight of a selection of the formula (Shucks - x in which x has a value from 1.9 to 2 inclusive and in which silo-Jane substantially all of the molecules have attached thereto at least a total of two silicon-bonded hydroxyl groups or alkoxy groups of less than 5 carbon atoms, a catalyst, and a cross-linking agent, said curable composition being curable at a temperature under 70C. with a curing exposure time of under 3 minutes.
The preferred release coating is prepared from a compost-lion comprising (1) a curable polysiloxane, (2) a catalyst, to) a cross-linking agent, (4) a fast-cure additive, and (5) an anchorage additive.
I ~2~63~ 557-2797 The release coating composition can be applied to the imaging film by conventional means and cured at temperatures sufficiently low so as to prevent adverse effects upon the layer of image able material. The release coating is also sufficiently permeable so as to allow moisture to escape from the image able layer, thereby reducing the "halo" effect. In addition, the coating is sufficiently flexible so that the film bearing it can be imaged in commercially available infrared copying machines, e.g., EM Model 45 infrared copier. Toner powder from pie n paper copies will not stick to this coating when the imaging film is processed in a conventional thermal imaging apparatus, e.g., an infrared copier.
DETAILED DESCRIPTION
The type of film contemplated for use in the present invention is any imaging film which can be imaged by being exposed to thermal energy, e.g. infrared radiation, while in surface-to-surface contact with an original.
A particularly appropriate type of thermally image able film contemplated for use in the present invention is described in Isbrandt, et at, U.S. Patent No. 4,423,139. This film can be imaged by means of infrared radiation. This film comprises a polymeric film substrate transparent to visible light, bearing an image able layer on at least one surface thereof. Substrate materials which are suitable for this invention include polycarbon-ales, polyesters, polyacrylates, polystyrene, and polypropylene.
A preferred substrate is polyvinylidene chloride primed polyester film. The preferred polyester is polyethylene terephthalate.
I 22~763~
The image able layer comprises a nitrate salt, e.g., nickel nitrate, at least one Luke dye, e.g., 3,7-di(N,N-diethyl-amino)l0-benzoyl phenoxazine, and a binder, e.g., cellulose acetate bitterroot, one or more aromatic compounds which form quinines, dominoes, or quinonimes upon oxidation, e.g., catcall, and l-phenyl-3-pyrazolidinone or derivatives thereof. The layer can also contain a material which supplies hydrogen ions, e.g., an acidic material such as phthalic acid. Upon the application of a sufficient amount of thermal energy, the nitrate salt will oxidize the Luke dye, resulting in a change in color.
Other thermally image able films that are suitable for use in the present invention are described in Owen, U.S. Patent No.
2,910,277; Grant, U.S. Patent No. 3,080,254; and Newman et at, U.S. Patent No. 3,682,684. Owen describes a heat-sensitive chemically reactive eopy-sheet comprising a thin flexible carrier web coated with a visibly heat-sensitive coating comprising (1) a film-forming binder, (2) a noble metal salt of an organic acid, and (3) a eyelid organic reducing agent for the noble metal ions, having an active hydrogen atom attached to an atom which is select ted from the class of oxygen, nitrogen and carbon atoms and is dir-wetly attached to an atom of the cyclic ring. Grant describes a heat-sensitive copy sheet comprising the same ingredients as contained in Owen and further including a sufficient amount of phthalazine to cause observable darkening of the thermographic image. In both Owen and Grant, the preferred film-forming binder is polystyrene resin, the preferred noble metal salts of organic acid are silver Bennett and silver Stewart, and the preferred reducing agents are 3,4-dihydroxybenzoie acid and methyl gullet.
-pa- ~7~3~ 557-2797 Newman et at describes a heat-sensitive sheet material including a thin visibly heat-sensitive layer having wide exposure latitude and comprising a mixture of ferris and silver soaps of long chain fatty acids, a toner for the silver image, and a finlike kirk-lent for the soaps. An example of ferris and silver soap mixture is ferris surety and silver Bennett. An example of a toner is phthalazinone, and .
examples of finlike co-reactants for the soaps are pyrogallic acid, catcall,
3,4-dihydroxybenzoic acid, methyl gullet, and Bunnell pyrogallol.
Compositions for preparing the organopolysiloxane coatings suitable for the present invention must be curable at -temperatures under 70~C with an exposure time of under 3 minutes. Longer cure times or higher curing temperatures or both would be detrimental to the imaging chemistry of the thermal imaging system.
Organopolysiloxanes suitable for the present invention include hydroxy-terminated or alkoxy-terminated polyalkylsiloxanes, for example, organopolysilox-aye obtained by curing a mixture of selections consisting essentially of from .1 to 3% by weight of methylhydrogenpolysiloxane and from 97 to 99.9% by weight of a selection of the formula (CH3)xsiO4-x in which x has a value from 1.9 to 2 inclusive and in which selection substantial fly all of the molecules have attached there-to at least a total of two silicon-bonded hydroxyl groups and/or alkoxy groups of less than 5 carbon atoms, as desk cried in United States Patent No. 3,061,567; cured epoxypolysiloxanes and their blends with epoxy-terminated sullenness, as disclosed in United States Patent No.
Compositions for preparing the organopolysiloxane coatings suitable for the present invention must be curable at -temperatures under 70~C with an exposure time of under 3 minutes. Longer cure times or higher curing temperatures or both would be detrimental to the imaging chemistry of the thermal imaging system.
Organopolysiloxanes suitable for the present invention include hydroxy-terminated or alkoxy-terminated polyalkylsiloxanes, for example, organopolysilox-aye obtained by curing a mixture of selections consisting essentially of from .1 to 3% by weight of methylhydrogenpolysiloxane and from 97 to 99.9% by weight of a selection of the formula (CH3)xsiO4-x in which x has a value from 1.9 to 2 inclusive and in which selection substantial fly all of the molecules have attached there-to at least a total of two silicon-bonded hydroxyl groups and/or alkoxy groups of less than 5 carbon atoms, as desk cried in United States Patent No. 3,061,567; cured epoxypolysiloxanes and their blends with epoxy-terminated sullenness, as disclosed in United States Patent No.
4,313,988.
Organopolysiloxanes of the type disclosed in United States Patent No.
3,061,567 can be prepared from compositions comprising if) a silicone resin, (2) a catalyst, (3) a cross-linking agent, and, optionally, a fast-cure additive, and an anchorage additive.
A commercially available silicone resin which has been found -to be use-fur for this invention is Sulfa* 294, which is available from Dow Corning Corporation.
* Trademark I ~2276~ 557-2797 Catalysts are desirable for reducing the time required and heat input necessary to cure the aforementioned silicone resins. Catalysts useful in the practice of this invention include dialkyltin salts, wherein the alkyd groups contain from 1 to 6 carbon atoms. Catalysts that are preferred are represented by the following general formula:
1l (C4Hg)2Sn(OCR)2 wherein R is -CH(C2H5)(CH2)3CH3, SHEA, 2 10 3 Commercially available catalysts which have been found to be useful in the practice of this invention include Dow Conning AYE and Dow Corning ZOO, both of which are avail-able from Dow Corning Corporation, dibutyltin diacetate available from Alga Products, and dibutyltin dilaurate, available from Alga Products and MOB Reagents.
Cross-linking agents can advantageously be employed for promoting cure. Cross-linking agents suitable for the alone-mentioned silicone resins include ortho-silicates, for example, tetramethoxyethoxyethylsilicate.
Commercially available cross-linking agents which have been found to be useful in the practice of this invention include Dow Corning C4-2117, available from Dow Corning Corporation, tetraethoxysilane, available from Alga Products, tetrapropoxysilane, available from PER Research Chemicals. Dow Corning C4-2117 has the following formula:
Si~o-cH2-cH2-ocH2cH2-ocH3)4 I;' I, .
-pa- 557-2797 An anchorage additive can also be added to the sift-cone resin-containing composition to improve the adhesion ox the coating to the substrate. A commercially available anchorage additive is Sulfa 297, available from Dow Corning Corporation.
This additive also is useful it 27~i3~j for lncreasillg the pot life of the catalyzed coating composition formulation. Other pot-life extenders include an hydrous alcohols, kittens, and acetic acid. Represent native examples of anilydrous alcohols are methanol,
Organopolysiloxanes of the type disclosed in United States Patent No.
3,061,567 can be prepared from compositions comprising if) a silicone resin, (2) a catalyst, (3) a cross-linking agent, and, optionally, a fast-cure additive, and an anchorage additive.
A commercially available silicone resin which has been found -to be use-fur for this invention is Sulfa* 294, which is available from Dow Corning Corporation.
* Trademark I ~2276~ 557-2797 Catalysts are desirable for reducing the time required and heat input necessary to cure the aforementioned silicone resins. Catalysts useful in the practice of this invention include dialkyltin salts, wherein the alkyd groups contain from 1 to 6 carbon atoms. Catalysts that are preferred are represented by the following general formula:
1l (C4Hg)2Sn(OCR)2 wherein R is -CH(C2H5)(CH2)3CH3, SHEA, 2 10 3 Commercially available catalysts which have been found to be useful in the practice of this invention include Dow Conning AYE and Dow Corning ZOO, both of which are avail-able from Dow Corning Corporation, dibutyltin diacetate available from Alga Products, and dibutyltin dilaurate, available from Alga Products and MOB Reagents.
Cross-linking agents can advantageously be employed for promoting cure. Cross-linking agents suitable for the alone-mentioned silicone resins include ortho-silicates, for example, tetramethoxyethoxyethylsilicate.
Commercially available cross-linking agents which have been found to be useful in the practice of this invention include Dow Corning C4-2117, available from Dow Corning Corporation, tetraethoxysilane, available from Alga Products, tetrapropoxysilane, available from PER Research Chemicals. Dow Corning C4-2117 has the following formula:
Si~o-cH2-cH2-ocH2cH2-ocH3)4 I;' I, .
-pa- 557-2797 An anchorage additive can also be added to the sift-cone resin-containing composition to improve the adhesion ox the coating to the substrate. A commercially available anchorage additive is Sulfa 297, available from Dow Corning Corporation.
This additive also is useful it 27~i3~j for lncreasillg the pot life of the catalyzed coating composition formulation. Other pot-life extenders include an hydrous alcohols, kittens, and acetic acid. Represent native examples of anilydrous alcohols are methanol,
5 ethanol, and isopropanol. Representative examples of j kittens are methyl ethyl kitten and methyl isopropyl j Isetone.
Sulfa 297 has the following formula:
O
OKAY
R --S i-o SHEA
OUCH
wherein Al is a long chain molecule ending in C-C
or COCK
Preferably I contains from 1 to 5 carbon atoms.
Ike concentration of each ingredient can vary, the particular amount of each depending upon the combine-lion of properties needed, as explained hereinafter.
When employing Sulfa 294 resin, it is preferred that the resin be dissolved in an aliphatic or aromatic solvent, such as, for example, Hutton, VIM & P
naphtha, Tulane, and blends of Tulane and Hutton. Some surfaces such as polyethylene may call or high levels of aliphatic solvents to obtain uniform wetting. It is preferred that the coa~incJ composition formulation, hereinafter alternatively referred to as coating bath, con Eerily 2 Jo 10 percent by wow silicone. The level of catalyst can vary, depending upon the curing temperature and time desired. When Dow Corning AYE catalyst is used with Sulfa 294 resin, it is preferred that the concentration of catalyst be Eroln 10 to 30 percent by weight more preferably Lo to 18 percent by weicJht, based it (-u JOY sulkily cellulose; Wylie Low CornincJ~ ZOO
catalyst is wised with Swahili') 2'~1 resin, it is preferred - ~276~
that 5 to 15 percent by sleight catalyst, based on weight of sulkier solids, be employed. When accelerated cure is desired, Dow Corning C4-2117 fast cure additive can be used at a level of 5 to 20 percent by weight, preferably 8 to 17 percent by weight, based on weight of silicone solids. If Dow Corning C4-2117 fast cure additive is used, either 3 to 8 percent by weight, based on weight of silicone solids, of Sulfa 297 anchorage additive or 1 to i 5 percent by weight an hydrous alcohol, based on weight ox total coating solution, should be used as a pot life extender.
The ingredients err preparing the curable silicone poller composition can be combined by introducing them into a vessel, and mixing them by any suitable mulled, such as, for example, stirring. Because of possible too rapid reaction of East-cure additive, e.g. Dow Corning C4-2117, with catalyst, e.g. Dow Corning ZOO, the asker a~clitive ~lloulcl lo doled and mixed well before addition of catalyst.
The composition can be applied to the surface of the imaging film by any of the techniques known in the art, such as, for example, knife coating, Mayer rod coating, curtain coaxing, extrusion bar coating, and rotogravure coating. The composition is coated over the surface of tile film bearing the image able layer formulation, thus acting as a top coat. The composition is preferably applied to the surface of the imaging film by coating from an organic solvent. However, solvent less coating is an acceptable method when using the squeeze roll coating technique.
3 Catalyst and cross-linking agents are critical in that proper selection thereof will permit coating by means of efficient methods, such as, for example rotogravure and-reverse roll.
Phthalic acid and catcall present in the imaging chelnistry tend to inhibit Lowe cut of the release coating rally, a Long airy time Lo Nile imaging chemistry allows for adequate cure, lout a short dry Tony for that layer l I- 12~76~
reduces the likelihood of adequate cure. The additives employed with the formulation for preparing the release coating help to promote a faster cure and improved anchorage.
i 5 Epoxysiloxane polymers of the type disclosed in U.S. Patent No. 4,313,988 are represented by the formula, Messiah Sue no.
wherein R2 is a lower alkyd group of one to three carton atoms, R3 is a monovalent hydrocarbon radical of 4 to 20 carbon atoms, E is a monovalent epoxy-containing hydrocarbon radical, M is a sill group R2Si , R2R3Si -or Russ , where R2, R3, and E are defined above, a is 5 to 200, b is 0 or up to 20~ of a, Ahab is 5 to 200, c may be 0 when Jo is Russ or greater than 0 but less than 20~ of the value of a Ahab) when M is R2Si , R2R3Si or Russ and n is 1 to 75. In the above formula, the preferred R group is methyl, and the preferred M group is Russ - when c is 0, and R2Si when c is greater than 0.
Also, when c is 0 and M is l~2~Si , n is 1 to 5, and preferably n is 1 or 2.
The preferred b is 0.
Illustrative examples of the monovalent hydrocarbon radical, R3, in the above formula are alkyd radicals such as bottle, isobutyl, tert-butyl, Huxley, octal and oc~adecyl; aureole radicals such as phenol, naphthyl and - bisphenylyl; alkaryl radicals such as toll and xylyl;
aralkyl radicals such as phenylmethyl, phenylpropyl and uhenylhexyl; and cycloaliphatic radicals such as cyclopentyl, cyclohexyl and ~-cyclohexylpropyl; and ether 3 oxygen- or ester oxyc3en-containillc3 radicals such as ethoxyuropyl, butoxyhutyl, and etiloxycarbonyluropy:L and the l lice. 'Lowe prel~erLed [c3 is a Lky.l of Do carbon atoms.
~z2~63~
The selection grouts, ! -so-, -I to-, and -lo-, are ordered or randomly arranged in tile epoxypolysiloxane and the l~onovalen~ epoxy-containinc~ hydrocarbon radical, E, kennels a least one polymeri~able epoxy group.
I of _ the remainder being composed ox carbon and hydrogen, free Ox acetylenic unsatura1ion and in addition Jo the oxen oxygen can contain ether, o , or carbonyl oxygen, e.g., o --OX--.
Illustrative examples of E are;
-CH2CH2 ~CHCH2 1 -CH(CH3)C O
-Cll2CH2CH20CH2CHCH20 [ire,, gamma-glycidoxyproQyl]
15 -CH2CH2 it beta-(3,4-epoxycyelohexyl)ethyl]
I
-CH,''H~CH3) Ho -Cl-12C~2C~12 ~OCH2C~IC~
-12- ~27~3~
.
In the above epoxy-containing hydrocarbon radical, the epoxy group is preferably located at the terminal position of the radical, but it need not be a terminal group.
Epoxy-terminated sullenness can be used optionally with the epoxypolysiloxanes in the coating formulation of this invention. Use of such epoxy-terminated sullenness enables the release performance of the coating to be varied. These epoxy-terminated sullenness are compounds or Interlace having polymerizable epoxy group(s) and a polymerizable Solon group, the bridging of these groups being through a non-hydrolyzable aliphatic, aromatic or aromatic and aliphatic diva lent hydrocarbon linkage which may contain ether or carbonyl oxygen linking groups. The exterminated Solon is represented by the formula, (E Syrup wherein E is an epoxy-containing monovalent hydrocarbon radical defined above, p is 1 to 3 (preferably 3) and R4 can be an aliphatic hydrocarbon radical of less than 10 carbon atoms such as alkyd (methyl, ethyl, isopropyl, bottle), an alkenyl such a ally or vinyl, or an azalea radical such as Eormyl, acutely, or propionyl. Because o-f availability and performance, the preferred R4 is a lower alkyd such as knothole or ethyl. Many illustrative examples are described in U.S. Patent No. 4,049,861.
In addition to the Solon, any hydrolyzate of the above sullenness can be used. Roy hydrolyzate is formed by partial or complete hydrolysis of the Solon or groups as described further in U.S. Patent No. 4,049,861.
3 The amount of the epoxy-terminated Solon or hydrolyze can rancJe Eroln to about 98% of the epoxypolysiloxane used, the amount being determined by the release perforlnance desired. Gellerally, the hither amounts ivy the hither release values.
122~
Curing of the epoxypolysiloxane-containing compositions of this invention can be effected by mixing with conventional epoxy curing catalysts and may additionally require heat or radiation. Examples of epoxy curing catalysts are tertiary amine, Lewis acids and their complexes, such as BF3 and complexes with ethers and amine; antimony halide-phosphorus containing ester complexes, such as with organophosphonates, mentioned below;
polyaromatic iodonium and sulfonium complex salts (e.g., having SbF6, SbF50H, PF6, BF4, or AsF6 anions, as disclosed in U.S.
Patent No. 4,101,513) and organic acids and their salts or other derivatives such as the highly fluorinated sulfonic and sulfonylic acids as described in U.S. Patent No. 4,049,861. The presence of the catalyst in the cured composition does not affect its efficacy as a release material.
In the practice of this invention the epoxypolysilox-anew catalyst, and optionally, the epoxy-terminated Solon are mixed in a solvent or, where possible, without solvent. The amount of catalyst used is about 1 to I by weight of the epoxy composition. The resultant material is coated on the image able layer and cured at ambient temperatures or, where necessary, heated to bring about cure. Solvents which can be used include ethyl acetate, isopropyl acetate, acetone, methyl ethyl kitten, Hutton, Tulane, and mixtures thereof. The exact coating technique is not especially critical and any of several well known procedures can be used. Warned rods, such as a Mayer bar, or a rotogravure applicator roll having, for example, 80 lines per in, provide unit form coating. Optionally, a mixing spray nozzle having a line for the epoxypolysiloxane fluid or solution and a separate line for the , . . .
lZ27636 -aye- 557-2797 catalyst solution can be used.
he coating thickness of the organopolysiloxane release coating can be controlled to obtain optimum performance. Coating weights in excess of 2.1 g/m2 tend to become soft and to deform upon exposure to heat. This .., ~227~3~
deformation can lead to irregularities in image areas, resulting in light scattering, Wesley in turn can produce dark spots in the projected image. The preferred range Ox coating weight is from about 0.108 g/m2 to about 1.076 j 5 cg/m2. Tie most preferred range is from about 0.108 g/m2 to about 0.538 g/m2 In some situations, a barrier coat must be interposed between the layer bearing the imaging chemicals and the release coating in order to permit the release lo coating to cure. An examples of a suitable substance for barrier coats is chlorinated polyisoprene (erg , Purloin S-20, con~nercially available from Hercules, Inc.).
As a formulation for preparing a release coating for thermally image able films, the composition of this Lo invention is superior to those in conventional use for the following reasons:
(1) the composition can be cured at temperatures below about 70C, low enough to prevent damage to imaging chemistry;
(2) the composition can be coated with a high speed coating apparatus, e.g., rotogravure, reverse roll;
(3) the cured coating is sufficiently permeable to moisture, resulting in reduction of image edge haziness, or "ghosting";
(4) the cured coating allows better release than coatings currently used in the art;
(S) the cured coating has good release from toner powder with the result that toner powder will 3 not adhere to the surface of the film The imaging film of the present invention is also vile useful in thermal printing devices, such as the Hewlett-Packard 9800 series, The thermal print heads are extremely hot, e.g., grow r ho :L00C, and eye have? a nclency of icon Ox L toll ~her~llcll:Ly image able materials from the substrate, resulting in fouled print heads. The -15~ 76~
cohesive strength of the coating, combined with its low coefficient of friction, render it useful for separating the print head from the thermally image able materials.
The Hollowing examples present specific illustra-} 5 lions of the present invention. It should be understood that the invention is not intended to be limited to specific details to be set earth therein.
EXAMPLE I
A composition for preparing a silicone polymer 10 release coating was prepared from a formulation containing the following ingredients in the amounts indicated:
Ingredient Amount Resin (Swahili 294) 4,00 g Hutton 32.80 g 15 ethyl ethyl kitten 8.20 g Cross-linking agent (Dow Corning Q2-7131) 0.075 g Catalyst (Dow Corning ZOO) 0.150 g The composition was coated over the image able layer of a sheet of transparent infrared image able film by means of knife coating. The wet coating thickness was 2 miss (50.8 I). The coating was dried at a temperature of :l40F
~60C) for 3 minutes.
In this and the following ExaTnples II and III the transparent infrared imageahle film was 4 mix (100 I) Luke polyethylene terel)hthala~e sheet bearing on one Injury surface thereof- an ilnageal~:L(? lucre coated prom a i5Ormulatio,l containing the Hollowing ingredients in the 3 alienates indicated nut _ Amount Nickel nitrate [Nina 0.102 g 2(2'-hydroxy-5'-methylpheny:L)-benzotriazole 0.100 g 1(3-bromo-~N,N dLmethylamino-phenyl)-2(2'-5'-chloro-1',3',3'-trimethylindolyl)ethene 0.084 g Phthalic acid Owls g l-Phenyl-3-pyrazolidinone 0,102 g lo Catcall 0.0~7 g Vinylidene chloride-acrylonitrile copolymer (Saran F-310, avail-able from Dow Chemical Company) 1.500 g Walt ncJ agent (Flurried FC-430, fluorinated alkyd ester available from Minnesota Mining and Manufacturing Company) 0.001 g 'l'etrahydrofuran 1.333 g Methyl ethyl kitten 4.980 Prior to coating, the above formulation was scaled-up L500X
and rotogravure coated with a 79.4 lines/in. knurl at 125 train with an oven dwell time of 68 seconds at a temperature of 180~F (82C).
Identical plain paper copies were employed as originals to determine the relative amount of toner adhering to the infrared imaging film. The effectiveness of the silicone release coaling was measured by comparing the optical density values on release coated and uncoated film from the same lot. The optical densities were JO measured with a Macbeth Model TDSO~AM densitometer. The images were made on a EM Model 45 infrared transparency maker. The treated and untreated film samples were Ted through the transparency malcer side-by-side so that both were exposed to identical conditions. uncoated polyester felon was used as a control. The results are set forth in Table I:
63~
I ,'~
Jo I I I o I I I o, I
'clue o It I I no O O
I o o g Lo .,, r~,~looooo U I Lo on g IT d' go I
000~ I Jo .~'~ owe Jo I Lo or En Lo I I
Jo I I l Al O Jo O H 1 o'er 4 rrJ H
h AL- I H Jo I I r I I: rat I
rut rl or' pi I roll C Jo Jo 63~
Untreated infrared image able film, i.e., elm not having a release coating, should remove more toner from an original, i.e., a plain paper copy bearing removable toner powder, than should an infrared image able illume treated will the release coating of the present invention. Thy toner which adheres to the untreated film will block light and thereby raise the transmission optical density readincJs.
untreated image able ill and treated image able film should give the same optical density readings when the image is prepared prom a printed original, i.e. an original having no removable toner, assuming that the films are selected Erwin the same slot. Tiffs wow indeed true (See Sample A, Table I When untreated polyester film having no image receiving layer was used, only the base optical density ox the film should was observed see Sample A, Table I). When a plain paper copy original having removable toner was used to produce a transparency with untreated polyester film having no image receiving layer, an image resulting from removed toner was observed and measured (See Sample C, Table I).
A transparency prepared from a toned original and an infrared image able film treated with an effective toner release coating should exhibit a lower optical density reading Han a transparency prepared from a toned original and an untreated infrared imatJeable film from the same lo, solely due to the absence of adhering toner material on the treated film. This was shown to be true in Samples I, C, D, and E of ruble I, Furthermore, because toner deposition on the untreated film was not uniform, the standard 3 deviation of tune average image density readings was greater for the untreated films than for the treated films. (See Samples I, C, D, and E of fable I). In contrast, standard deviations calculated For transparencies prepared from printed originals were approximately the same for both treated and untreated films (Lee Sample A, Table I).
--lo-- ~%2~-33~
EX~MJ?LE II
This example demonsL-Kates that only certain classes ox silken resins are suitable o'er use yin the prune invention.
Tile following fable sets forth ingredients and amounts for four dif~erenl: release coating formulations:
TUB II
Ingredient Amount A B C D
Rosen Sulfa 294 3.12~
Swahili 3 10.000 Sulfa 291 2.500 Sulfa 292 ~.3S0 15Fast-cure additive Dow Corning C~-2117 0.300 0.300 0.300 0.250 Anchorage additive Sulfa 297 0.200 0.150 0 200 0.100 catalyst Dow Corning ZOO 0.300 0.300 0.300 Dow Corning 25 solvent Isopropanol 3.221 3.925 4.670 4.650 Methyl ethyl Acetone ].. 07~
Hutton 38.655 35~325 42.030 36.585 3 Each formulation was coated over the immobile layer of a sheet ox transparent infrared image able elan by means ox knife coating. The wet coating thickness was 2 miss (50.8 I). The following table sets forth cure results l-or the previously mentioned release coaxing formulations -20- ~27~3~
TABLE III
Temperature Time Formulation (Cj Seiko) Nature of cure -- .. . I. _ A 68 60 Good B 82 90 Good C 77 90 Good D 82 90 None Formulation D did no cure at 82C because Dow Corning 23 catalyst requires a higher curing temperature than does Dow Corning MY 176 catalyst. Of the three formulations wherein cure was effected, only formulation A could be cured at a temperature below 70C. Formulations B and C
would not be suitable for use in the present invention because the temperatures required to cure the release coating formulation would adversely affect the layer of image able material.
EXAMPLE III
A composition or preparing an epoxysiloxane release coating was prepared prom a formulation containing the following ingredients in the amounts indicated:
Ingredient Amount Al 31 ¦ 1 3 (CH3)3Sio----SiO- --Six ---Seiko SHEA 135 (SHEA I
of H
. SHEA _ 15 3.0 g -Hutton 37.6 g Methyl ethyl kitten 9.4 g Antimony pentachloride/di.metlly:Lmethyl n. 3 q l?ht~gphonal:te complex i36 The composition was coated over the image able layer of a sheet of infrared image able film by means of knife coating. The wet coating thickness was 2 miss (50.8 em). The coating was dried at a temperature of 150F (66C) -for 1-1/2 minutes.
The effectiveness of the epoxypolysiloxane release coating was determined by the same procedures and with the same equipment as used in Example I. The results are set forth in Table IV:
-2.2- ~27~;3~
I r-(I JO O r-l O O ED
I Al O O O C: C l O
Al Us ' I
Jo .
mu I I
.
rl Al I) ~71 Us r'l O O O O O
Roy I
2 a U Jo r-l I I I Jo rl ~1_1 .~) I
Jo Jo b 1_1 I us .r1 ,-1 in I I' I r r l I r~3 I a H X Pi (I I
so to I us:;
I c: .
Jo ) ox a I I U) ~2~7636 From table IV, it is apparent that untreated infrared image able film removed more toner from an original than did an infrared image able film treated with an epoxypolysiloxane release coating. In addition, standard deviation values of average image density readings were greater for untreated films than for treated films.
EXAMPLE IV
In this example, the transparent thermally image able film was 4 mix (0.102 mm) thick polyethylene terephthalate sheet bearing on one major surface thereof an image able layer prepared according to the procedure described below. All parts are parts by weight unless indicated otherwise.
A first solution containing (a) 5 parts silver been-ate, (b) 40 parts acetone, and (c) 5 parts methyl ethyl kitten was ball milled for 24 hours. A second solution containing (a) 13.00 parts polyvinyl acetate resin, (b) 83.20 parts acetone, (c) 0.20 parts benzotria~ole, (d) 0.60 parts tetrachlorophthalic android, and (e) 3.00 parts methyl gullet was stirred until the resin had dissolved. Twenty parts of the first solution was combined with ten parts of the second solution, and the combination was stirred for 5 minutes with an air mixer. The immobile compost it ion was coated over the polyethylene terephthalate sheet with a flat bed knife coaler at 3.0 mix orifice and was dried in an oven at 82C for 2 minutes. A third solution containing 5 parts cell-lose acetate bitterroot resin and 95 parts acetone was stirred until the resin had dissolved. This solution was coated over the dried image able composition with a knife coaler at 2.0 mix orifice and was dried in an oven at 82C for 2 minutes. A fourth solution ,~,~
I
-aye- 557-2797 containing 7.5 parts polyvinyl bitterly and 92.5 parts ethanol was coated over the cellulose acetate bitterroot resin layer with a knife coaler at 2.0 mix orifice and was dried in an oven at 82C for 2 minutes A composition for preparing a silicon polymer release kitten was prepared Loom a formulation c~ntainin(J
the following ingredients in the amounts indicated:
Amount 5 Ingredient (parts by weight) Resin (Sulfa 294) 4.00 Anchorage additive (Swahili 297) 0.25 Hutton 3~.00 Methyl ethyl kitten 6.00 10 Fast cure additive (Clue) 0.75 Catalyst (Dow Corning ZOO) 0.62 Hutton and methyl ethyl Acetone were blended, and then, in order were added the resin the East-cure additive, the anchorage additive, and the catalyst. The release coating composition was coated over the polyvinyl bitterly layer by means cue a knife coaler a a 2 mix orifice. The coating was dried in an oven at 82C -for 2 minutes The effectiveness ox the rslea~e coating was determined through the measurement and comparison ox the optical density of the image on tile paper original prior Jo making a transparency, after making a transparency with thermally imacgeable film not treated with a silicone release coating, and after making a transparerlcy with thermally image able film treated with a silicone release coating (A fresh original was used to prepare each tratlsparency.) Originals were Include on a Cadillac Model 15~
copier. Transparencies were made on a prewarmed EM Model 45 Transparency Make Roy optical densities were measured with a Luke Ludlow Tl~924 densitometer. The results in 3 the Elan table represent the average of four samples.
12~7~3~
TABLE V
Optical density Standard deviation Original 1.21 0.08 Untreated film 0.98 0.22 Treated film 1.21 0.12 Loss of optical density and increase in standard deviation is observed when comparing the images on originals before and after imaging with untreated film. Loss of optical density results from toner particles being torn from the paper original. Because tearing away of toner particles is not uniform, the standard deviation increases. When treated film is used, no loss of optical density is observed. Furthermore, the standard deviation is only slightly higher than that of the original image, thus indicating the uniformity of image is about the same.
"
Sulfa 297 has the following formula:
O
OKAY
R --S i-o SHEA
OUCH
wherein Al is a long chain molecule ending in C-C
or COCK
Preferably I contains from 1 to 5 carbon atoms.
Ike concentration of each ingredient can vary, the particular amount of each depending upon the combine-lion of properties needed, as explained hereinafter.
When employing Sulfa 294 resin, it is preferred that the resin be dissolved in an aliphatic or aromatic solvent, such as, for example, Hutton, VIM & P
naphtha, Tulane, and blends of Tulane and Hutton. Some surfaces such as polyethylene may call or high levels of aliphatic solvents to obtain uniform wetting. It is preferred that the coa~incJ composition formulation, hereinafter alternatively referred to as coating bath, con Eerily 2 Jo 10 percent by wow silicone. The level of catalyst can vary, depending upon the curing temperature and time desired. When Dow Corning AYE catalyst is used with Sulfa 294 resin, it is preferred that the concentration of catalyst be Eroln 10 to 30 percent by weight more preferably Lo to 18 percent by weicJht, based it (-u JOY sulkily cellulose; Wylie Low CornincJ~ ZOO
catalyst is wised with Swahili') 2'~1 resin, it is preferred - ~276~
that 5 to 15 percent by sleight catalyst, based on weight of sulkier solids, be employed. When accelerated cure is desired, Dow Corning C4-2117 fast cure additive can be used at a level of 5 to 20 percent by weight, preferably 8 to 17 percent by weight, based on weight of silicone solids. If Dow Corning C4-2117 fast cure additive is used, either 3 to 8 percent by weight, based on weight of silicone solids, of Sulfa 297 anchorage additive or 1 to i 5 percent by weight an hydrous alcohol, based on weight ox total coating solution, should be used as a pot life extender.
The ingredients err preparing the curable silicone poller composition can be combined by introducing them into a vessel, and mixing them by any suitable mulled, such as, for example, stirring. Because of possible too rapid reaction of East-cure additive, e.g. Dow Corning C4-2117, with catalyst, e.g. Dow Corning ZOO, the asker a~clitive ~lloulcl lo doled and mixed well before addition of catalyst.
The composition can be applied to the surface of the imaging film by any of the techniques known in the art, such as, for example, knife coating, Mayer rod coating, curtain coaxing, extrusion bar coating, and rotogravure coating. The composition is coated over the surface of tile film bearing the image able layer formulation, thus acting as a top coat. The composition is preferably applied to the surface of the imaging film by coating from an organic solvent. However, solvent less coating is an acceptable method when using the squeeze roll coating technique.
3 Catalyst and cross-linking agents are critical in that proper selection thereof will permit coating by means of efficient methods, such as, for example rotogravure and-reverse roll.
Phthalic acid and catcall present in the imaging chelnistry tend to inhibit Lowe cut of the release coating rally, a Long airy time Lo Nile imaging chemistry allows for adequate cure, lout a short dry Tony for that layer l I- 12~76~
reduces the likelihood of adequate cure. The additives employed with the formulation for preparing the release coating help to promote a faster cure and improved anchorage.
i 5 Epoxysiloxane polymers of the type disclosed in U.S. Patent No. 4,313,988 are represented by the formula, Messiah Sue no.
wherein R2 is a lower alkyd group of one to three carton atoms, R3 is a monovalent hydrocarbon radical of 4 to 20 carbon atoms, E is a monovalent epoxy-containing hydrocarbon radical, M is a sill group R2Si , R2R3Si -or Russ , where R2, R3, and E are defined above, a is 5 to 200, b is 0 or up to 20~ of a, Ahab is 5 to 200, c may be 0 when Jo is Russ or greater than 0 but less than 20~ of the value of a Ahab) when M is R2Si , R2R3Si or Russ and n is 1 to 75. In the above formula, the preferred R group is methyl, and the preferred M group is Russ - when c is 0, and R2Si when c is greater than 0.
Also, when c is 0 and M is l~2~Si , n is 1 to 5, and preferably n is 1 or 2.
The preferred b is 0.
Illustrative examples of the monovalent hydrocarbon radical, R3, in the above formula are alkyd radicals such as bottle, isobutyl, tert-butyl, Huxley, octal and oc~adecyl; aureole radicals such as phenol, naphthyl and - bisphenylyl; alkaryl radicals such as toll and xylyl;
aralkyl radicals such as phenylmethyl, phenylpropyl and uhenylhexyl; and cycloaliphatic radicals such as cyclopentyl, cyclohexyl and ~-cyclohexylpropyl; and ether 3 oxygen- or ester oxyc3en-containillc3 radicals such as ethoxyuropyl, butoxyhutyl, and etiloxycarbonyluropy:L and the l lice. 'Lowe prel~erLed [c3 is a Lky.l of Do carbon atoms.
~z2~63~
The selection grouts, ! -so-, -I to-, and -lo-, are ordered or randomly arranged in tile epoxypolysiloxane and the l~onovalen~ epoxy-containinc~ hydrocarbon radical, E, kennels a least one polymeri~able epoxy group.
I of _ the remainder being composed ox carbon and hydrogen, free Ox acetylenic unsatura1ion and in addition Jo the oxen oxygen can contain ether, o , or carbonyl oxygen, e.g., o --OX--.
Illustrative examples of E are;
-CH2CH2 ~CHCH2 1 -CH(CH3)C O
-Cll2CH2CH20CH2CHCH20 [ire,, gamma-glycidoxyproQyl]
15 -CH2CH2 it beta-(3,4-epoxycyelohexyl)ethyl]
I
-CH,''H~CH3) Ho -Cl-12C~2C~12 ~OCH2C~IC~
-12- ~27~3~
.
In the above epoxy-containing hydrocarbon radical, the epoxy group is preferably located at the terminal position of the radical, but it need not be a terminal group.
Epoxy-terminated sullenness can be used optionally with the epoxypolysiloxanes in the coating formulation of this invention. Use of such epoxy-terminated sullenness enables the release performance of the coating to be varied. These epoxy-terminated sullenness are compounds or Interlace having polymerizable epoxy group(s) and a polymerizable Solon group, the bridging of these groups being through a non-hydrolyzable aliphatic, aromatic or aromatic and aliphatic diva lent hydrocarbon linkage which may contain ether or carbonyl oxygen linking groups. The exterminated Solon is represented by the formula, (E Syrup wherein E is an epoxy-containing monovalent hydrocarbon radical defined above, p is 1 to 3 (preferably 3) and R4 can be an aliphatic hydrocarbon radical of less than 10 carbon atoms such as alkyd (methyl, ethyl, isopropyl, bottle), an alkenyl such a ally or vinyl, or an azalea radical such as Eormyl, acutely, or propionyl. Because o-f availability and performance, the preferred R4 is a lower alkyd such as knothole or ethyl. Many illustrative examples are described in U.S. Patent No. 4,049,861.
In addition to the Solon, any hydrolyzate of the above sullenness can be used. Roy hydrolyzate is formed by partial or complete hydrolysis of the Solon or groups as described further in U.S. Patent No. 4,049,861.
3 The amount of the epoxy-terminated Solon or hydrolyze can rancJe Eroln to about 98% of the epoxypolysiloxane used, the amount being determined by the release perforlnance desired. Gellerally, the hither amounts ivy the hither release values.
122~
Curing of the epoxypolysiloxane-containing compositions of this invention can be effected by mixing with conventional epoxy curing catalysts and may additionally require heat or radiation. Examples of epoxy curing catalysts are tertiary amine, Lewis acids and their complexes, such as BF3 and complexes with ethers and amine; antimony halide-phosphorus containing ester complexes, such as with organophosphonates, mentioned below;
polyaromatic iodonium and sulfonium complex salts (e.g., having SbF6, SbF50H, PF6, BF4, or AsF6 anions, as disclosed in U.S.
Patent No. 4,101,513) and organic acids and their salts or other derivatives such as the highly fluorinated sulfonic and sulfonylic acids as described in U.S. Patent No. 4,049,861. The presence of the catalyst in the cured composition does not affect its efficacy as a release material.
In the practice of this invention the epoxypolysilox-anew catalyst, and optionally, the epoxy-terminated Solon are mixed in a solvent or, where possible, without solvent. The amount of catalyst used is about 1 to I by weight of the epoxy composition. The resultant material is coated on the image able layer and cured at ambient temperatures or, where necessary, heated to bring about cure. Solvents which can be used include ethyl acetate, isopropyl acetate, acetone, methyl ethyl kitten, Hutton, Tulane, and mixtures thereof. The exact coating technique is not especially critical and any of several well known procedures can be used. Warned rods, such as a Mayer bar, or a rotogravure applicator roll having, for example, 80 lines per in, provide unit form coating. Optionally, a mixing spray nozzle having a line for the epoxypolysiloxane fluid or solution and a separate line for the , . . .
lZ27636 -aye- 557-2797 catalyst solution can be used.
he coating thickness of the organopolysiloxane release coating can be controlled to obtain optimum performance. Coating weights in excess of 2.1 g/m2 tend to become soft and to deform upon exposure to heat. This .., ~227~3~
deformation can lead to irregularities in image areas, resulting in light scattering, Wesley in turn can produce dark spots in the projected image. The preferred range Ox coating weight is from about 0.108 g/m2 to about 1.076 j 5 cg/m2. Tie most preferred range is from about 0.108 g/m2 to about 0.538 g/m2 In some situations, a barrier coat must be interposed between the layer bearing the imaging chemicals and the release coating in order to permit the release lo coating to cure. An examples of a suitable substance for barrier coats is chlorinated polyisoprene (erg , Purloin S-20, con~nercially available from Hercules, Inc.).
As a formulation for preparing a release coating for thermally image able films, the composition of this Lo invention is superior to those in conventional use for the following reasons:
(1) the composition can be cured at temperatures below about 70C, low enough to prevent damage to imaging chemistry;
(2) the composition can be coated with a high speed coating apparatus, e.g., rotogravure, reverse roll;
(3) the cured coating is sufficiently permeable to moisture, resulting in reduction of image edge haziness, or "ghosting";
(4) the cured coating allows better release than coatings currently used in the art;
(S) the cured coating has good release from toner powder with the result that toner powder will 3 not adhere to the surface of the film The imaging film of the present invention is also vile useful in thermal printing devices, such as the Hewlett-Packard 9800 series, The thermal print heads are extremely hot, e.g., grow r ho :L00C, and eye have? a nclency of icon Ox L toll ~her~llcll:Ly image able materials from the substrate, resulting in fouled print heads. The -15~ 76~
cohesive strength of the coating, combined with its low coefficient of friction, render it useful for separating the print head from the thermally image able materials.
The Hollowing examples present specific illustra-} 5 lions of the present invention. It should be understood that the invention is not intended to be limited to specific details to be set earth therein.
EXAMPLE I
A composition for preparing a silicone polymer 10 release coating was prepared from a formulation containing the following ingredients in the amounts indicated:
Ingredient Amount Resin (Swahili 294) 4,00 g Hutton 32.80 g 15 ethyl ethyl kitten 8.20 g Cross-linking agent (Dow Corning Q2-7131) 0.075 g Catalyst (Dow Corning ZOO) 0.150 g The composition was coated over the image able layer of a sheet of transparent infrared image able film by means of knife coating. The wet coating thickness was 2 miss (50.8 I). The coating was dried at a temperature of :l40F
~60C) for 3 minutes.
In this and the following ExaTnples II and III the transparent infrared imageahle film was 4 mix (100 I) Luke polyethylene terel)hthala~e sheet bearing on one Injury surface thereof- an ilnageal~:L(? lucre coated prom a i5Ormulatio,l containing the Hollowing ingredients in the 3 alienates indicated nut _ Amount Nickel nitrate [Nina 0.102 g 2(2'-hydroxy-5'-methylpheny:L)-benzotriazole 0.100 g 1(3-bromo-~N,N dLmethylamino-phenyl)-2(2'-5'-chloro-1',3',3'-trimethylindolyl)ethene 0.084 g Phthalic acid Owls g l-Phenyl-3-pyrazolidinone 0,102 g lo Catcall 0.0~7 g Vinylidene chloride-acrylonitrile copolymer (Saran F-310, avail-able from Dow Chemical Company) 1.500 g Walt ncJ agent (Flurried FC-430, fluorinated alkyd ester available from Minnesota Mining and Manufacturing Company) 0.001 g 'l'etrahydrofuran 1.333 g Methyl ethyl kitten 4.980 Prior to coating, the above formulation was scaled-up L500X
and rotogravure coated with a 79.4 lines/in. knurl at 125 train with an oven dwell time of 68 seconds at a temperature of 180~F (82C).
Identical plain paper copies were employed as originals to determine the relative amount of toner adhering to the infrared imaging film. The effectiveness of the silicone release coaling was measured by comparing the optical density values on release coated and uncoated film from the same lot. The optical densities were JO measured with a Macbeth Model TDSO~AM densitometer. The images were made on a EM Model 45 infrared transparency maker. The treated and untreated film samples were Ted through the transparency malcer side-by-side so that both were exposed to identical conditions. uncoated polyester felon was used as a control. The results are set forth in Table I:
63~
I ,'~
Jo I I I o I I I o, I
'clue o It I I no O O
I o o g Lo .,, r~,~looooo U I Lo on g IT d' go I
000~ I Jo .~'~ owe Jo I Lo or En Lo I I
Jo I I l Al O Jo O H 1 o'er 4 rrJ H
h AL- I H Jo I I r I I: rat I
rut rl or' pi I roll C Jo Jo 63~
Untreated infrared image able film, i.e., elm not having a release coating, should remove more toner from an original, i.e., a plain paper copy bearing removable toner powder, than should an infrared image able illume treated will the release coating of the present invention. Thy toner which adheres to the untreated film will block light and thereby raise the transmission optical density readincJs.
untreated image able ill and treated image able film should give the same optical density readings when the image is prepared prom a printed original, i.e. an original having no removable toner, assuming that the films are selected Erwin the same slot. Tiffs wow indeed true (See Sample A, Table I When untreated polyester film having no image receiving layer was used, only the base optical density ox the film should was observed see Sample A, Table I). When a plain paper copy original having removable toner was used to produce a transparency with untreated polyester film having no image receiving layer, an image resulting from removed toner was observed and measured (See Sample C, Table I).
A transparency prepared from a toned original and an infrared image able film treated with an effective toner release coating should exhibit a lower optical density reading Han a transparency prepared from a toned original and an untreated infrared imatJeable film from the same lo, solely due to the absence of adhering toner material on the treated film. This was shown to be true in Samples I, C, D, and E of ruble I, Furthermore, because toner deposition on the untreated film was not uniform, the standard 3 deviation of tune average image density readings was greater for the untreated films than for the treated films. (See Samples I, C, D, and E of fable I). In contrast, standard deviations calculated For transparencies prepared from printed originals were approximately the same for both treated and untreated films (Lee Sample A, Table I).
--lo-- ~%2~-33~
EX~MJ?LE II
This example demonsL-Kates that only certain classes ox silken resins are suitable o'er use yin the prune invention.
Tile following fable sets forth ingredients and amounts for four dif~erenl: release coating formulations:
TUB II
Ingredient Amount A B C D
Rosen Sulfa 294 3.12~
Swahili 3 10.000 Sulfa 291 2.500 Sulfa 292 ~.3S0 15Fast-cure additive Dow Corning C~-2117 0.300 0.300 0.300 0.250 Anchorage additive Sulfa 297 0.200 0.150 0 200 0.100 catalyst Dow Corning ZOO 0.300 0.300 0.300 Dow Corning 25 solvent Isopropanol 3.221 3.925 4.670 4.650 Methyl ethyl Acetone ].. 07~
Hutton 38.655 35~325 42.030 36.585 3 Each formulation was coated over the immobile layer of a sheet ox transparent infrared image able elan by means ox knife coating. The wet coating thickness was 2 miss (50.8 I). The following table sets forth cure results l-or the previously mentioned release coaxing formulations -20- ~27~3~
TABLE III
Temperature Time Formulation (Cj Seiko) Nature of cure -- .. . I. _ A 68 60 Good B 82 90 Good C 77 90 Good D 82 90 None Formulation D did no cure at 82C because Dow Corning 23 catalyst requires a higher curing temperature than does Dow Corning MY 176 catalyst. Of the three formulations wherein cure was effected, only formulation A could be cured at a temperature below 70C. Formulations B and C
would not be suitable for use in the present invention because the temperatures required to cure the release coating formulation would adversely affect the layer of image able material.
EXAMPLE III
A composition or preparing an epoxysiloxane release coating was prepared prom a formulation containing the following ingredients in the amounts indicated:
Ingredient Amount Al 31 ¦ 1 3 (CH3)3Sio----SiO- --Six ---Seiko SHEA 135 (SHEA I
of H
. SHEA _ 15 3.0 g -Hutton 37.6 g Methyl ethyl kitten 9.4 g Antimony pentachloride/di.metlly:Lmethyl n. 3 q l?ht~gphonal:te complex i36 The composition was coated over the image able layer of a sheet of infrared image able film by means of knife coating. The wet coating thickness was 2 miss (50.8 em). The coating was dried at a temperature of 150F (66C) -for 1-1/2 minutes.
The effectiveness of the epoxypolysiloxane release coating was determined by the same procedures and with the same equipment as used in Example I. The results are set forth in Table IV:
-2.2- ~27~;3~
I r-(I JO O r-l O O ED
I Al O O O C: C l O
Al Us ' I
Jo .
mu I I
.
rl Al I) ~71 Us r'l O O O O O
Roy I
2 a U Jo r-l I I I Jo rl ~1_1 .~) I
Jo Jo b 1_1 I us .r1 ,-1 in I I' I r r l I r~3 I a H X Pi (I I
so to I us:;
I c: .
Jo ) ox a I I U) ~2~7636 From table IV, it is apparent that untreated infrared image able film removed more toner from an original than did an infrared image able film treated with an epoxypolysiloxane release coating. In addition, standard deviation values of average image density readings were greater for untreated films than for treated films.
EXAMPLE IV
In this example, the transparent thermally image able film was 4 mix (0.102 mm) thick polyethylene terephthalate sheet bearing on one major surface thereof an image able layer prepared according to the procedure described below. All parts are parts by weight unless indicated otherwise.
A first solution containing (a) 5 parts silver been-ate, (b) 40 parts acetone, and (c) 5 parts methyl ethyl kitten was ball milled for 24 hours. A second solution containing (a) 13.00 parts polyvinyl acetate resin, (b) 83.20 parts acetone, (c) 0.20 parts benzotria~ole, (d) 0.60 parts tetrachlorophthalic android, and (e) 3.00 parts methyl gullet was stirred until the resin had dissolved. Twenty parts of the first solution was combined with ten parts of the second solution, and the combination was stirred for 5 minutes with an air mixer. The immobile compost it ion was coated over the polyethylene terephthalate sheet with a flat bed knife coaler at 3.0 mix orifice and was dried in an oven at 82C for 2 minutes. A third solution containing 5 parts cell-lose acetate bitterroot resin and 95 parts acetone was stirred until the resin had dissolved. This solution was coated over the dried image able composition with a knife coaler at 2.0 mix orifice and was dried in an oven at 82C for 2 minutes. A fourth solution ,~,~
I
-aye- 557-2797 containing 7.5 parts polyvinyl bitterly and 92.5 parts ethanol was coated over the cellulose acetate bitterroot resin layer with a knife coaler at 2.0 mix orifice and was dried in an oven at 82C for 2 minutes A composition for preparing a silicon polymer release kitten was prepared Loom a formulation c~ntainin(J
the following ingredients in the amounts indicated:
Amount 5 Ingredient (parts by weight) Resin (Sulfa 294) 4.00 Anchorage additive (Swahili 297) 0.25 Hutton 3~.00 Methyl ethyl kitten 6.00 10 Fast cure additive (Clue) 0.75 Catalyst (Dow Corning ZOO) 0.62 Hutton and methyl ethyl Acetone were blended, and then, in order were added the resin the East-cure additive, the anchorage additive, and the catalyst. The release coating composition was coated over the polyvinyl bitterly layer by means cue a knife coaler a a 2 mix orifice. The coating was dried in an oven at 82C -for 2 minutes The effectiveness ox the rslea~e coating was determined through the measurement and comparison ox the optical density of the image on tile paper original prior Jo making a transparency, after making a transparency with thermally imacgeable film not treated with a silicone release coating, and after making a transparerlcy with thermally image able film treated with a silicone release coating (A fresh original was used to prepare each tratlsparency.) Originals were Include on a Cadillac Model 15~
copier. Transparencies were made on a prewarmed EM Model 45 Transparency Make Roy optical densities were measured with a Luke Ludlow Tl~924 densitometer. The results in 3 the Elan table represent the average of four samples.
12~7~3~
TABLE V
Optical density Standard deviation Original 1.21 0.08 Untreated film 0.98 0.22 Treated film 1.21 0.12 Loss of optical density and increase in standard deviation is observed when comparing the images on originals before and after imaging with untreated film. Loss of optical density results from toner particles being torn from the paper original. Because tearing away of toner particles is not uniform, the standard deviation increases. When treated film is used, no loss of optical density is observed. Furthermore, the standard deviation is only slightly higher than that of the original image, thus indicating the uniformity of image is about the same.
"
Claims (13)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A film which can be imaged by thermal energy comprising:
(a) a substrate, (b) a layer of thermally imageable material coated on at least one major surface of said substrate, (c) a cured organopolysiloxane release coating, capable of releasing toner, coated over said layer of imageable material, said release coating being formed from a curable composition comprising a mixture of siloxanes consisting essentially of from 0.1 to 3% by weight of methylhydrogenpolysiloxane and from 97 to 99.9% by weight of a siloxane of the formula in which x has a value from 1.9 to 2 inclusive and in which silo-xane substantially all of the molecules have attached thereto at least a total of two silicon-bonded hydroxyl groups or alkoxy groups of less than 5 carbon atoms, a catalyst, and a cross-link-ing agent, said curable composition being curable at a temperature under 70°C. with a curing exposure time of under 3 minutes.
(a) a substrate, (b) a layer of thermally imageable material coated on at least one major surface of said substrate, (c) a cured organopolysiloxane release coating, capable of releasing toner, coated over said layer of imageable material, said release coating being formed from a curable composition comprising a mixture of siloxanes consisting essentially of from 0.1 to 3% by weight of methylhydrogenpolysiloxane and from 97 to 99.9% by weight of a siloxane of the formula in which x has a value from 1.9 to 2 inclusive and in which silo-xane substantially all of the molecules have attached thereto at least a total of two silicon-bonded hydroxyl groups or alkoxy groups of less than 5 carbon atoms, a catalyst, and a cross-link-ing agent, said curable composition being curable at a temperature under 70°C. with a curing exposure time of under 3 minutes.
2. The film of claim 1 wherein said film is transmissive to visible light.
3. The film of claim 1 wherein the substrate is a polymeric film.
4. The film of claim 3 wherein said polymeric film substrate is polyethylene terephthalate.
5. The film of claim 1 wherein the imageable material com-prises a binder, nitrate salt, and at least one leuco dye.
6. The film of claim 1 wherein said catalyst is a dialkyl-tin salt.
7. The film of claim 6 wherein said catalyst is represented by the formula wherein R is -CH(C2H5)(CH2)3CH3, -CH3, or -(CH2)10CH3.
8. The film of claim 1 wherein said cross-linking agent is a tetraalkoxysilane (silicate).
9. The film of claim 8 wherein said cross-linking agent is represented by the formula Si?O-CH2-CH2-OCH2CH2-OCH3)4.
10. The film of claim 1 further including an anchorage additive.
11. A film which can be imaged by thermal energy comprising:
(a) a substrate, (b) a layer of thermally imageable material coated on at least one major surface of said substrate, (c) an organopolysiloxane release coating, capable of re-leasing toner, coated over said layer of imageable material, said release coating being formed from a curable composition comprising (1) a curable epoxypolysiloxane which is represented by the formula, wherein R2 is a lower alkyl group of one to three carbon atoms, R3 is a monovalent hydrocarbon radical of 4 to 20 carbon atoms, E is a monovalent epoxy-containing hydrocarbon radical, M is a silyl group R2Si-, R2R3Si-, or R2ESi-, where R2, R3, and E are defined above, a is 5 to 200, b is 0 or up to 20% of a, a+b is 5 to 200, c may be 0 when M is R2ESi- or is greater than 0 but less than 20% of the value of (a+b) when M is R2Si-, R2R3Si- or R2ESi-, and n is 1 to 75;
provided that the monovalent epoxy-containing hydrocarbon radical, E contains at least one polymerizable epoxy group, , the remainder being composed of carbon and hydrogen free of acety-lenic unsaturated and in addition to the oxirane oxygen can con-tain either, -O-, or carbonyl oxygen, , and (2) 0 to about 98% by weight of the epoxypolysiloxane described in (1) of an epoxy-terminated silane wherein said epoxy-terminated silane is represented by the formula, , wherein E is an epoxy-containing monovalent hydrocarbon radical defined above, p is 1 to 3 and R4 can be an aliphatic hydrocarbon radical of less than 10 carbon atoms, and an effective amount of an epoxy curing catalyst, said curable composition being curable at a temperature under 70°C with a curing exposure time of under 3 minutes.
(a) a substrate, (b) a layer of thermally imageable material coated on at least one major surface of said substrate, (c) an organopolysiloxane release coating, capable of re-leasing toner, coated over said layer of imageable material, said release coating being formed from a curable composition comprising (1) a curable epoxypolysiloxane which is represented by the formula, wherein R2 is a lower alkyl group of one to three carbon atoms, R3 is a monovalent hydrocarbon radical of 4 to 20 carbon atoms, E is a monovalent epoxy-containing hydrocarbon radical, M is a silyl group R2Si-, R2R3Si-, or R2ESi-, where R2, R3, and E are defined above, a is 5 to 200, b is 0 or up to 20% of a, a+b is 5 to 200, c may be 0 when M is R2ESi- or is greater than 0 but less than 20% of the value of (a+b) when M is R2Si-, R2R3Si- or R2ESi-, and n is 1 to 75;
provided that the monovalent epoxy-containing hydrocarbon radical, E contains at least one polymerizable epoxy group, , the remainder being composed of carbon and hydrogen free of acety-lenic unsaturated and in addition to the oxirane oxygen can con-tain either, -O-, or carbonyl oxygen, , and (2) 0 to about 98% by weight of the epoxypolysiloxane described in (1) of an epoxy-terminated silane wherein said epoxy-terminated silane is represented by the formula, , wherein E is an epoxy-containing monovalent hydrocarbon radical defined above, p is 1 to 3 and R4 can be an aliphatic hydrocarbon radical of less than 10 carbon atoms, and an effective amount of an epoxy curing catalyst, said curable composition being curable at a temperature under 70°C with a curing exposure time of under 3 minutes.
12. The film of claim 11 wherein said catalyst is a complex of antimony pentachloride and dimethyl methyl phosphonate.
13. Method of preparing a transparency by means of a thermal imaging process comprising the steps of (a) contacting an image-bearing original with the trans-parent film of claim 2, (b) applying thermal energy to the original whereby the original imagewise absorbs said thermal energy and transfers said thermal energy to the transparent film to form a copy of the image of the original on the transparent film, and (c) separating said original from said transparent film.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US52020783A | 1983-08-04 | 1983-08-04 | |
| US520,207 | 1983-08-04 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1227636A true CA1227636A (en) | 1987-10-06 |
Family
ID=24071614
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000458436A Expired CA1227636A (en) | 1983-08-04 | 1984-07-09 | Film for thermal imaging |
Country Status (6)
| Country | Link |
|---|---|
| EP (1) | EP0134126B1 (en) |
| JP (1) | JPS6044393A (en) |
| AU (1) | AU572525B2 (en) |
| BR (1) | BR8403790A (en) |
| CA (1) | CA1227636A (en) |
| DE (1) | DE3468376D1 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0612285B1 (en) * | 1991-10-11 | 1997-04-02 | Minnesota Mining And Manufacturing Company | Coated thin film for imaging |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US393658A (en) * | 1888-11-27 | Theodore a | ||
| JPS5315743B2 (en) * | 1973-08-14 | 1978-05-26 | ||
| US3986997A (en) * | 1974-06-25 | 1976-10-19 | Dow Corning Corporation | Pigment-free coating compositions |
| US4071644A (en) * | 1974-11-14 | 1978-01-31 | General Electric Company Silicone Products Department | Method for rendering flexible sheet material non-adherent |
| JPS51120804A (en) * | 1975-04-14 | 1976-10-22 | Dainippon Printing Co Ltd | Plate for lithographic printing |
| JPS5391803A (en) * | 1977-01-18 | 1978-08-12 | Dainippon Printing Co Ltd | Method of producing lithographic printing plate |
| US4223072A (en) * | 1977-12-23 | 1980-09-16 | Dow Corning Corporation | Flexible coating resins from siloxane resins having a very low degree of organic substitution |
| US4313988A (en) * | 1980-02-25 | 1982-02-02 | Minnesota Mining And Manufacturing Company | Epoxypolysiloxane release coatings for adhesive materials |
| EP0076490B1 (en) * | 1981-10-05 | 1986-02-05 | Kuraray Co., Ltd. | Paper coating agent |
-
1984
- 1984-07-09 AU AU30395/84A patent/AU572525B2/en not_active Ceased
- 1984-07-09 CA CA000458436A patent/CA1227636A/en not_active Expired
- 1984-07-23 JP JP59152744A patent/JPS6044393A/en active Granted
- 1984-07-30 BR BR8403790A patent/BR8403790A/en not_active IP Right Cessation
- 1984-08-03 DE DE8484305308T patent/DE3468376D1/en not_active Expired
- 1984-08-03 EP EP19840305308 patent/EP0134126B1/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| DE3468376D1 (en) | 1988-02-11 |
| JPS6044393A (en) | 1985-03-09 |
| AU572525B2 (en) | 1988-05-12 |
| JPH0514637B2 (en) | 1993-02-25 |
| AU3039584A (en) | 1985-02-07 |
| EP0134126A1 (en) | 1985-03-13 |
| BR8403790A (en) | 1985-07-09 |
| EP0134126B1 (en) | 1988-01-07 |
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