IMAGE-RECEIVING FILM FOR ELECTROGRAPHY

Abstract: An image-receiving film for electrography comprising a transparent substrate and an image-receiving layer provided on at least one surface of the substrate, wherein at least one silicone oil adsorbent selected from the group consisting of fatty acids, esters of fatty acids, derivatives of fatty acids and metallic soaps, or the group consisting of polyhydric alcohols, higher alcohols and higher dialcohols contained in the image-receiving layer or an overcoat layer provided on the image-receiving layer.

Description: Image-Receiving Film for Electrography The present invention relates to an image-receiving film for electrography. More particularly, it relates to a film useful for receiving an image formed by electrography. The term "electrography" used herein is intended to mean systems including electrophotography, electroradiography and magnetography, as widely recognized in the field of imaging and described in a number of patent documents and the like. The image- receiving film of the present invention can be usefully utilized for the preparation of an OHP film particularly by color electrophotography among the electrographic systems. In recent years, various electronic equipment manufacturers have put electrophotographic full-color copying machines on the market. In fact, the advance of full-color electrophotographic techniques in recent years is significant, and even copying machines, which can reproduce images having a quality close to printed matters or photographic prints, have now appeared. In the OHP films, however, there are problems to be solved. A particularly serious problem is as follows. In order to avoid the occurrence of the so-called "offset phenomenon," that is, the transfer of a toner on a fixation roller at the time of fixation of an image transferred onto an OHP film, a silicone oil is coated on the surface of the fixation roller, which unfavorably causes the surface of the OHP film to become oily. This problem is attributable to such a phenomenon that part of the silicone oil coated on the surface of the fixation roller is transferred from the surface onto the film. Further, when the oily film, as such, is inserted into a sleeve or a cover utilized for protection and storage of the OHP film, for example, Flip-Frame™ (registered trade mark) manufactured by 3M, U.S.A., particularly when the amount of the oil transferred to the film is large, the migration and accumulation of the oil (the so-called "oil pooling") occurs in a region where the film is in contact with the sleeve. The oil pooling is projected as a large eyesore at the time of projection of the OHP film. For this reason, the development of a technique for reducing the oiliness or oily feeling and removing the oil pooling has been desired in the field of OHP films. In order to reduce the oiliness of the OHP film attributable to the use of a silicone oil, Japanese Unexamined Patent Publication (Kokai) No. 5-173351 proposes an OHP film comprising a recording layer (an image-forming layer) having a capability of absorbing a silicone oil. The recording layer is composed mainly of a polymethacrylic ester/styrene copolymer (hydroxyl number: 40 or more) and a polymer of a quaternary ammonium salt. However, as is apparent from Comparative Example 3, which will be described later, the capability of this film to absorb the silicone oil still remains low even when the hydroxyl number of the polymethacrylic ester/styrene copolymer used in the recording layer is 80. Further, in such a film, although the adsorption of the silicone oil at the time of contact with the fixation roller is increased, the oil retention is so low that there is a fear of the oil pooling phenomena becoming severe. Furthermore, in the above film, the water absorption of the recording layer is so high that there is a fear of the recording layer absorbing moisture in air, thereby causing the silicone oil absorption and the image formability to be deteriorated with time. Furthermore, in the film, the composition of the recording layer is complicate, which unavoidably incurs an increase in cost. In order to prevent the occurrence of oil pooling at the time of contact of the OHP film with Flip-Frame™, U.S. Patent No. 5,208,093 proposes to incorporate, into an image-receiving layer comprising a polymer film having a thickness of 0.5 to 10 μm, particles at least half of which have a particle diameter enough to protrude from the image-receiving layer (for example, silica particles having a particle diameter of about 10 μm) . For example, as shown in Fig. 5, this novel film comprises a substrate 11 comprising a transparent polyethylene terephthalate film and, provided on said substrate, an image-receiving layer 12 comprising a polyester resin containing silica particles 15. The silicone oil from the fixation roller is absorbed into the image-receiving layer 12 on its surface to form an oil layer 17. When the film as shown in the drawing is housed in Flip-Frame™ 18, the occurrence of oil pooling can be effectively inhibited because the particle diameter of the silica particles 15 is larger than the thickness of the image-receiving layer 12. Since, however, the thin oil layer provided on the image-receiving layer is indispensable to this film, the problem of the oiliness to the touch cannot be solved. Accordingly, an object of the present invention is to provide an image-receiving film for electrography which enables the occurrence of an oil pooling phenomenon to be minimized (the inhibition of an oil pooling phenomenon) , the silicone oil once held on the image- receiving layer to remain held without rapid falling (an improvement in oil retention) and the transfer of the silicone oil, when touched by hand, to be reduced (a reduction in oiliness to the touch) . According to the present invention, the above- described object of the present invention can be attained by an imagereceiving film for electrography, comprising a transparent substrate or support and an image-receiving layer or receptor layer provided on at least one surface of said substrate, wherein said image-receiving layer contains at least one silicone oil adsorbent selected from the group consisting of fatty acids, esters of fatty acids, derivatives of fatty acids and metallic soaps. Further, according to the present invention, the above described object can be attained by an image- receiving film for electrography, comprising a transparent substrate and an image-receiving layer provided on at least one surface of said substrate, wherein said image-receiving layer contains at least one silicone oil adsorbent selected from the group consisting of polyhydric alcohols, higher alcohols and higher dialcohols . Furthermore, the above-described object can be • attained by an image-receiving film for electrography, comprising a transparent substrate or support and an image-receiving layer or receptor layer provided on at least one surface of said substrate, wherein said i age- receiving layer has on its surface an overcoat layer, and said overcoat layer contains at least one silicone oil adsorbent selected from the group consisting of fatty acids, esters of fatty acids, derivatives of fatty acids and metallic soaps. Furthermore, the above-described object can be attained by an image-receiving film for electrography, comprising a transparent substrate and an image-receiving layer provided on at least one surface of said substrate, wherein said imagereceiving layer has on its surface an overcoat layer, and said overcoat layer contains at least one silicone oil adsorbent selected from the group consisting of polyhydric alcohols, higher alcohols and higher dialcohols. In the present invention, the overcoat layer containing a silicone oil adsorbent may be provided on the image-receiving layer directly or alternatively through any intermediate layer. In general, the thickness of the overcoat layer is preferably in the range of from 0.01 to 10 g/m 2 in terms of the coverage. The construction and the mode of operation of the image receiving film for electrography according to the present invention will now be described in detail. Fig. 1 is a schematic cross-sectional view of a preferred embodiment of the image-receiving film according to the present invention. In this image- receiving film, an image-receiving layer 2 and an overcoat layer 3 are successively provided on one surface of a transparent substrate 1. The overcoat layer 3 comprises a specific compound having a carboxyl group (fatty acids, esters of fatty acids, derivatives of fatty acids and metallic soaps) or a specific compound having a hydroxyl group (polyhydric alcohols, higher alcohols and higher dialcohols) . In this embodiment, if necessary, the image-receiving layer 2 and the overcoat layer 3 may be provided also on the opposite side of the substrate 1 although this is not shown in the drawing. Further, it is also possible to interpose one or more additional layers, for example, between the image-receiving layer 2 and the overcoat layer 3 or on other ' positions, so far as the additional layer is not detrimental to the effect contemplated in the present invention. With respect to the transparent substrate, a suitable transparent film may be properly selected from plastic films commonly used as a substrate in the art. in the production of an image-receiving film. The suitable substrate is preferably a heat-resistant plastic film, and examples thereof include films of polyethylene terephthalate, polyethylene naphthalate, polymethyl acrylate, polymethyl methacrylate, cellulose triacetate, plyamides, polyimides, polyvinyl chloride, polyvinylidene chloride, polystyrene and polycarbonate. If necessary, the above-described plastic film may be subjected to a corona treatment or may have on its back surface a layer containing an antistatic agent. The thickness of the substrate is preferably in the range of from 10 to 200 μm. When the thickness of the substrate is smaller than 10 μm, no satisfactory heat resistance and mechanical strength can be attained. On the other hand, when the thickness of the substrate exceeds 200 μm, the light transmittance (transparency, is lowered and, at the same time, the handleability beccmes poor. Therefore, it is preferred to avoid both the above cases. The thickness of the substrate is more preferably in the range of from 50 to 175 μm, most preferably in the range of from 75 to 150 μm. The regulation of the thickness of the substrate to the above-described range can offer a good balanced film construction and, at the same time, would reduce the cost per unit weight. Also with respect to the image-receiving layer, a suitable material may be properly selected from resin materials commonly used as a material for an image- receiving layer in the art in the production of an irr.age- receiving film. A suitable material for the image- receiving layer is preferably a resin material which enables a toner, particularly a color toner, to be easily fused thereto and, at the same time, can provide an image having a high transparency. Examples of the suitable material include polyester resin, styrene/acrylic resin, epoxy resin, urethane resin and polyolefin resin. Among them, polyester resin is particularly preferred. The thickness of the image-receiving layer is preferably in the range of from 0.1 to 100 g/nr in terms of the coverage. When the thickness is less than 0.1 g/nr, it cannot receive the toner satisfactorily. On the other hand, when the thickness exceeds 100 g/m 2 , the light transmittance becomes low and, at the same time, the film cannot be carried smoothly within copying machines. The coverage of the image-receiving layer is more preferably in the range of from 0.5 to 10 g/m" most preferably in the range of from 0.1 to 5 g/m". The regulation of the coverage of the image-receiving layer in the above- described range would offer a good balanced film construction and, at the same time, facilitate the production of the image-receiving layer. As described above, the overcoat layer provided on the image-receiving layer contains at least one compound having a carboxyl group, selected from the group consisting of fatty acids, ester of fatty acids, derivatives of fatty acids and metallic soaps, as a silicone oil adsorbent. In the present invention, these silicone oil adsorbent compounds serve as a gelling agent for the silicone oil, that is, are substances which can cause gelation of the fed silicone oil by taking advantage of heat fed by the fixation roller. The gelation inhibits the migration of the silicone oil and, at the same time, reduces the oiliness on the surface of the film. Typical examples of the carboxyl group-containing compound (fatty acids, esters of fatty acids, derivatives of fatty acids and metallic soaps) useful as a silicone oil adsorbent in the present invention are as follows. The term "fatty acids" is intended to mean chain compounds having one carboxyl group, and include lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, montanic acid, oleic acid, linolenic acid, eleostearic acid, 12-hydroxystearic acid and the like. The term "Esters of fatty acids" is intended to mean ester compounds of the above-mentioned fatty acids with onoalcohols, dialcohols or trialcohols, and typical examples thereof include stearic glycerin ester, palmitic glycerin ester and the like. The term "derivatives of fatty acids" is intended to mean compounds containing one or more carboxyl groups in the molecular chain thereof exclusive of said fatty acids and esters thereof, and as examples thereof, there are mentioned phthalic acid, maleic acid, malic acid, succinic acid and the like. The term "metallic soaps" is intended to mean metal salts of fatty acids, and include aluminum stearate, sodium stearate, potassium stearate, lead stearate, zinc stearate and the like. Among these, silicone oil adsorbent compounds, palmitic acid, myristic acid, stearic acid, aluminum stearate and zinc stearate are easily available and inexpensive. 12-hydroxystearic acid has in its molecule a hydroxyl group as well as a carboxyl group, so that the silicone oil adsorption is better. As described above, the overcoat layer contains at least one compound selected from the group consisting of polyhydric alcohols, higher alcohols and higher dialcohols. More specifically, preferable examples of the hydroxyl group containing compound useful as a silicone oil adsorbent in the present invention include dibenzylidenesorbitol and 1,10 decanediol . The compounds exemplified above are suitable because they have a high capability of forming a hydrogen bond and a good silicone oil adsorption. In the practice of the present invention, the above described silicone oil adsorvent compounds are generally used alone, however, if desired, a mixture of two or more types of the compounds may also be used in combination. Preferred compounds having a carboxyl group, as a silicone oil adsorbent, to have a melting point of from 40 to 150°C and be solid at room temperature. When the melting point is below 40°C, the compound is liquid at room temperature, so that the resultant film has a pocr handleability. On the other hand, when the melting point exceeds 150°C, it becomes difficult to melt the compound at a temperature fed by the fixation roller, which results in difficulty in fixing the toner successfully. The above silicone oil adsorbent compounds are suitably soluble in a non-solvent for the image-receiving layer from the viewpoint of production of thelovercoat layer. Specifically, in general, they are soluble in a lower alcohol, glycerin or the like, which is a non-solvent for the image receiving layer. In this case, the overcoat layer can be easily formed without detriment to the i age-receivinq layer at the time of coating. The overcoat layer may further comprises a polyester resin, a styrene resin and the like in addition to the above described compounds having a carboxyl group or a hydroxyl group as a silicone oil adsorbent. These additional resins are useful for improving the adhesion of the overcoat layer to the underlayer (image-receiving layer) . In this case, however, precautions should be taken so as not to lower the transparency of the overcoat layer. The use (as the additional resin) of a resin identical to or in the same type as the resin for the image-receiving layer is advantageous in that the improvement in adhesion is significant and no lowering in receptivity to the image is observed. The thickness of the overcoat layer comprising a silicone oil adsorbent compound is preferably in the range of from 0.01 to 10 g/m " in terms of the coverage. When the coverage is less than 0.01 g/nr, the effect of adsorbing the silicone oil is small. On the other hand, when it exceeds 10 g/m", the light transmittance is likely to be lowered. The coverage of the overcoat layer is more preferably in the range of from 0.1 to 1 g/m-, most preferably in the range of from 0.3 to 0.8 g/m". The regulation of the coverage of the overcoat layer in the above-described range offers a good balanced film construction and, at the same time, facilitates the formation of the overcoat layer. The image-receiving film according to the above embodiment has an additional advantage over an image- receiving film without an overcoat layer, in that a satisfactory effect can be attained using a very small amount of silicone oil adsorbent (compound having a carboxyl group or compound having a hydroxyl group) . However, the image-receiving film without an overcoat layer also has an additional advantage over the image- receiving film of the above embodiment in that the simple layer construction simlifies the production process and a thin film can be provided. Fig. 2 is a schematic cross-sectional view of another preferred embodiment of the image-receiving film of the present invention. The image-receiving film according to this embodiment comprises a transparent substrate 1 and, on one surface of the substrate, an image-receiving layer 4 comprising a silicone oil adsorbent (compound having a carboxyl group or compound having a hydroxyl group) . As with the image-receiving film shown in Fig. 1, the image-receiving film shown in Fig. 2 may further comprise any additional layer (not shown) . The transparent substrate 1 may be the same as that in the image-receiving film shown in Fig. 1. Further, the image-receiving layer 4 and, the silicone oil adsorbent incorporated therein may also be the same as those used in the image-receiving film shown in Fig. 1. In the image-receiving layer 4, the useful amount of the silicone oil adsorbent compound added is from 1 to 1000 parts by weight based on 100 parts by weight of the remaining resin in the image-receiving layer. When it is less than 1 part by weight, the intended effect cannot be attained; when it exceeds 1000 parts by weight, the light transmittance is lowered, which is likely to cause a lowering in image quality and haze development. The preferred amount of the compound (s) is from 10 to 500 parts by weight, most preferably in the range of from 30 to 300 parts by weight. The addition of the compound(s) in the above suitable amount yields a layer construction with balanced properties, and eliminates possible phase separation occurring between the silicone oil adsorbent compound and the remaining resin in the production of the image-receiving layer. Fig. 3 is a schematic cross-sectional view of a further preferred embodiment of the image-receiving film of the present invention. The image-receiving film according to this embodiment has the same construction as in Fig. 1, except that the image-receiving layer 2 provided on the transparent substrate 1 contains fine particles 5 (silica particles in this case) and is covered with the overcoat layer 3. The overcoat layer 3 comprises a silicone oil adsorbent (compound having a carboxyl group or compound having a hydroxyl group) . Fine particles include silica particles and fine particles of various other inorganic and organic materials are useful. Suitable examples of the fine particles include those of silica, alumina, calcium carbonate, diatomaceous earth, plymethacrylate and polystyrene. The incorporation of these fine particles into the image-receiving layer are favorable from the viewpoint of reducing the oil pooling phenomenon and more smoothly carrying the film (i.e., improving the feedability of the film) within copying machines. When the silica particles are incorporated into the image-receiving layer, they may be in the form of a primary particle or an aggregate of particles. The particle diameter of the silica particles or aggregate may be preferably in the range of from 1 to 100 μm. When it is less than 1 μm, the effect of reducing the oil pooling phenomenon is poor and an improvement in feedability is small. When it exceeds 100 μm, the light transmittance is lowered, which results in an increase in haze. The particle diameter is more preferably in the range of from 5 to 50 μm, most preferably in the range of from 8 to 25 μm. Preferably, the silica particle contains the above- described silicone oil adsorbent (compound having a carboxyl group or compound having a hydroxyl group) . When the silicone oil adsorbent compounds are incorporated into the image-receiving film in this way, the particles are protruded on the surface of image- receiving film. The intended effect can be attained even when the amount of the silicone oil adsorbent compound (s) added is small, and the effect is maintained, so that there is no fear of the light transmittance being lowered. Further, the silica particles may be incorporated into the overcoat layer instead of or in addition to the image receiving layer. This is suitable from the viewpoint of reducing the oil pooling phenomenon and improving the feedability of the film, and when added to the overcoat layer, the effect seen from the particles is larger for the amount added. According to a preferred embodiment of the present invention, the antistatic effect of the film can be enhanced by adding an antistatic agent to any layer constituting the image-receiving film. Examples of useful antistatic agents include quaternary ammonium salts and various clay particles. The addition of the antistatic agent reduces the surface resistivity of the image-receiving film. Therefore, the amount of the antistatic agent added is preferably determined by taking the surface resistivity of the film into consideration. Although the surface resistivity varies depending upon the specific copying machine used, it is suitably in the range of from 1 x 10 8 to 1 x 10 Ω. When it is less than 1 x 10 r Ω, the transfer of the toner is poor. On the other hand, when it exceeds 1 x 10 14 Ω, the film cannot be smoothly carried within copying machines. The surface resistivity is more preferably in the range of from 1 x 10 '' to 1 x 10 lj Ω. The image-receiving film of the present invention may be prepared by various techniques depending upon film layer construction and other factors. In one example of a useful technique, an image-receiving layer is formed by coating directly on a substrate film, and drying. After the resultant coating is dried, a solution of the selected silicone oil adsorbent and an antistatic agent dissolved in ethanol are coated. The coating operation may be carried out by coating methods commonly used in the art, such as Mayer bar coating, B & M extrusion coating, die coating, Narr coating, gravure coating and k ss coating. Mode of Operation As described above, the effect of the present invention relies largely on the function of the specific compound having a carboxyl group or a hydroxyl group used as a silicone oil adsorbent. This will now be described while taking 12-hydroxystearic acid as an example particularly with reference to a schematic diagram shown in Fig. 4. 12-Hydroxystearic acid is soluble in an oil at the melting point or above. When the resultant solution is allowed to stand, the temperature decreases with time, which causes molecules to be arranged through a hydrogen bend in a three-dimensional manner, so that a network structure 6 similar to that of polymeric compounds i≤ formed as a whole. It is considered that a silicone oil 7 is incorporated in the network structure 6 and gels. As a result, the migration of silicone oil is prevented, which contributes to a reduction in surface oiliness cf the film. EXAMPLES The present invention will now be described in mere detail with reference to the following examples. Example 1 A transparent polyester resin was coated on a 125 μm thick transparent polyester film (a substrate) at a coverage of 2.5 g/m' to form an image-receiving layer. Then, a solution of 94.5 g of 12-hydroxystearic acid and 12.6 g of an antistatic agent comprising a quaternary ammonium salt dissolved in 3043 g of ethanol was coated thereon by extrusion coating to form an overcoat layer. The coverage of the overcoat layer on a dry basis was 0.5 g/m" . An image was formed on the resultant image-forming film by means of a color copying machine. The imaged film was used as an OHP film to evaluate the properties. Laser Copia CLC200 (a registered trade mark) (a color laser copying machine manufactured by Canon Sales Co., Inc.) was used as the color copying machine. Oil pooling test The film under test was inserted into Flip-Frame- (a film holder manufactured by 3M, U.S.A.), and observation was made by visual inspection for pooling caused by a silicone oil. The results were evaluated based on the following three grades. [Excellent] No pooling observed [Good] Substantially no pooling observed [Failure] Pooling clearly observed Touch test (evaluation on oiliness) The film under test was touched with a finger, and the results were evaluated as follows. [Excellent] No oiliness observed [Good] Substantially no oiliness observed [Failure] Oiliness clearly observed Haze test In order to evaluate the occurrence of haze in the film under test, the haze value was measured with a haze meter manufactured by EYK Gardner (available under the designation XL-211j , and the results were evaluated as follows . [Excellent] Less than 8% [Good] 8% to less than 12* [Failure] Not less than 12% Image quality test The film under test was inserted into Flip-Frame- 1 , and an image was projected by means of OHP "M2180" manufactured by 3M, U.S.A. The projected image (test pattern) was observed by visual inspection, and the reproduction of the image was evaluated as follows. [Excellent] Complete reproduction [Good] Satisfactory reproduction [Failure] Unsatisfactory reproduction- No oil pooling was observed at all. In this connection, it is noteworthy that neither the background nor image had oil pooling. Further, no oiliness was felt when the surface of the film was touched with a finger. The haze value was very low, and the image reproduction was excellent. The results obtained in this example together with the results obtained in the other examp.es are given in the following Table 1. Example 2 The procedure of Example 1 was repeated, except that an image-receiving layer was formed by coating a solution of 300 g of a polyester resin (PS-2 manufactureα oy Kao Corp.) and 6.0 g of a polyester resin (VITEL 2200 manufactured by Goodyear Tire & Rubber Co.) as an adhesive composition for improving the adhesion to a toner, dissolved m 1347 g of toluene and 1347 g of methyl ethyl ketone. The coverage of the image-receiving layer was 2.5 g/m . Then, a solution of 68.8 g of 12- hydroxystearic acid and 16.1 g of an antistatic agent comprising a quaternary ammonium salt and 2.29 g of Silica MC-A manufactured by Nai-Gai Talc Co., Ltd. dissolved in 2207 g of ethanol was coated on the lmaσe- receiving layer to form an overcoat layer. The coverage of the overcoat layer was 0.5 g/m on a dry basis. As with Example 1, this example provided good results. The results are given in the following Table 1. Examples 3 to 7 The procedure of Example 1 was repeated, except that instead of 12-hydroxystearic acid, the following compounds were used in the same amounts as 12-hydroxy stearic acid. Example 3: dibenzyl-dienesorbitol Example 4: ammonium stearate Example 5: zinc stearate Example 6: stearic acid Example 7: 1, 10-decanediol As with Examples 1 and 2, Examples 3 to 7 provided good results. The results are shown in Table 1. Examples 8 to 10 The procedure of Example 1 was repeated, except that the antistatic agent used was a commercially available antistatic agent as noted below used in the same amounts as the antistatic agent used in Example 1. Example 8: Electrostopper QE (a cationic antistatic agent manufactured by Kao Corp.) Example 9: Chemistat 3033 (an anionic antistatic agent manufactured by Sanyo Kasei Kcgyo K.K.) Example 10: Adekamine (a cationic antistatic agent manufactured by Asahi Denka Kogyo Ltd.) As with Examples 1 to 7, Examples 8 to 10 provided good results, and no color dropout occurred. The results are shown in Table 1. Examples 11 and 12 The procedure of Example 1 was repeated, except that the coverage of the overcoat layer was changed as fellows. Example 11: 0.1 g/irr Example 12: 1 g/m" As with the above examples, Examples 11 and 12 provided good results. The results are shown in Table 1. Example 13 A solution of 0.50 g of 12-hydroxystearic acid, J.50 g of a polyester resin (PS-1 manufactured by Kao Corp.), 0.01 g of a polyester resin (VITEL 1200 manufactured by Goodyear Tire & Rubber Co.), 0.015 g of an antistatic agent derived from a quaternary ammonium salt dissolved in 2.16 g of toluene and 2.16 g of methyl ethyl ketone was coated using a #12 Mayer bar on a 125 μm thick transparent polyethylene terephthalate film (a substrate) at a coverage of 2.5 g/nr to form an image-receiving layer. The film as imaged in the same manner as described in Example 1, and the imaged film was tested for evaluation of properties. The results are shown in Table 1. Table 1 Test for image-receiving films Items for test Oil Image Pooling Touch Quality Ex. No. Test Test Haze Test Test 1 Excellent Excellent Excellent Excellent 2 Excellent Excellent Excellent Excellent 3 Excellent Excellent Excellent Excellent 4 Excellent Excellent Excellent Excellent 5 Excellent Excellent Excellent Excellent 6 Excellent Excellent Excellent Excellent 7 Excellent Excellent Excellent Excellent 8 Excellent Excellent Excellent Excellent 9 Excellent Excellent Excellent Excellent 10 Excellent Excellent Excellent Excellent 11 Good Good Excellent Excellent 12 Excellent Excellent Good Good 13 Good Good Good Good Comparative Examples 1 and 2 The procedure of Example 1 was repeated, except that, for comparison, 12-hydroxystearic acid was not added to the overcoat layer and the coverage of the overcoat layer was changed as follows. Comparative Example 1: 0.5 g/m" Comparative Example 2: 0.1 g/nr The results are given in the following Table 2. Comparative Example 3 In the present comparative example, the procedure described in Japanese Unexamined Patent Publication (Kokai) No. 5-173351 was repeated. 50 parts by weight of xylene, 10 parts by weight of methyl methacrylate, 11 parts by weight of n-butyl methacrylate, 10 parts by weight of 2-hydroxyethyl methacrylate, 18 parts by weight of styrene, 0.5 parts by weight of acrylic acid and 0.5 parts by weight of azobisisobutyronitrile were mixed together in a flask, and the mixture was stirred at 80°C for 2 hr to carry out a polymerization reaction. As a result, a polymethacrylic ester/styrene copolymer having a hydroxyl number of 80 was obtained. A solution comprising 20 parts by weight of the copolymer, 20 parts by weight of a polymer of a quaternary ammonium salt (Elecond PQ-50B manufactured by Soken Chemical Engineering Co., Ltd.), 30 parts by weight of toluene and 30 parts by weight of methyl isobutyl ketone was prepared and coated on a 5 mil-thick polyethylene terephthalate film at a coverage of 5 g/m" on a dry basis. As is apparent from Table 2, the image-receiving film thus obtained was unsatisfactory in silicone oil adsorption and other properties. [Table 2] Characteristic test for image-receiving films Items for test Oil Image Pooling Quality Ex. No. Test Touch Test Haze Test Test 1 Failure Failure Excellent Excellent 2 Failure Failure Excellent Excellent 3 Failure Failure Failure Failure According to the present invention, in image- receiving films, for example, for OHP, the occurrence of an oil pooling phenomenon can be reduced, and a silicone oil, which has been once held on an image-receiving layer, can be kept on the image-receiving layer. Further, it is also possible to reduce the transfer cf an silicone oil upon touch on the film with a finger. Moreover, according to the present invention, it is also possible to enhance the feedability of the film within a copying machine. In addition, in the present invention, the film construction is simple, and all the materials used are easily available and inexpensive, which contributes to a lowering in product cost. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 Fig. 1 is a schematic cross-sectional view of a preferred embodiment of the image-receiving film for electrography according to the present invention. Fig. 2 Fig. 2 is a schematic cross-sectional view of another preferred embodiment of the image-receiving film for electrography according to the present invention. Fig. 3 Fig. 3 is a schematic cross-sectional view of a further preferred embodiment of the image-receiving film for electrography according to the present invention. Fig. 4 Fig. 4 is a schematic diagram showing typical gelation of a silicone oil according to the present invention. Fig. 5 Fig. 5 is a schematic cross-sectional view showing an embodiment of the conventional image-receiving film for electrography. Description of Reference Numerals 1 substrate 2 image-receiving layer 3 overcoat layer 4 image-receiving layer 5 adsorptive particle 6 network structure of 12-hydroxystearic acid 7 silicone oil

Claims: Claims: 1. An image-receiving film for electrography, comprising a transparent substrate and an image-receiving layer provided on at least one surface of said substrate, wherein said image-receiving layer contains at least one silicone oil adsorbent selected from the group consisting of fatty acids, esters of fatty acids, derivatives cf fatty acids, metallic soaps, polyhydric alcohols, higher alcohols and higher dialcohols. 2. An image-receiving film for electrography, comprising a transparent substrate and an image-receiving layer provided on at least one surface of said substrate, wherein said image-receiving layer has on its surface an imaging receiving layer, and an overcoat layer, and said overcoat layer contains at least one silicone oil adsorbent selected from the group consisting of fatty acids, esters of fatty acids, derivatives of fatty acids, metallic soaps, polyhydric alcohols, higher alcohols and higher dialcohols. 3. An image-receiving film for electrography according to claim 1 wherein said silicone oil adsorbent is 12-hydroxystearic acid. 4. An image-receiving film for electrography according to claim 2 wherein said silicone oil adsorbent is dibenzylidenesorbitol or 1, 10-decanediol. 5. An image-receiving film for electrography according to claims 1 or 2, wherein said silicone oil adsorbent has a melting point of 40 to 150°C. 6. An image-receiving film for electrography according to any one of claims 1 to 3, wherein said silicone oil adsorbent is contained in silica particles.

Inventors: AOKI SHOZO, DOHGOSHI SHIGEAKI, KAMIYAMA KOJI, AOKI, SHOZO, DOHGOSHI, SHIGEAKI, KAMIYAMA, KOJI
Applicants: MINNESOTA MINING & MFG, MINNESOTA MINING AND MANUFACTURING COMPANY
Application year: 1995
Main classification: G03G7
IPC codes: G03G7