KR19990054800A - Overhead projection film for electrophotographic copying and manufacturing method thereof - Google Patents

Abstract

1. TECHNICAL FIELD OF THE INVENTION

The present invention relates to an overhead projection film for electrophotographic copying and a method of manufacturing the same.

2. The technical problem to be solved by the invention

The present invention provides an image-receiving layer coating liquid prepared by mixing a thermoplastic polymer exhibiting excellent toner adhesion and coating strength as a water-soluble, a thermosetting polymer and a blocking agent having a crosslinked structure in the molecule, on at least one side of a transparent or semitransparent polymer film. Overhead coating film for electrophotographic copying and its manufacturing method which can not only solve the problems that occur when using organic solvents, but also greatly reduce the manufacturing cost, and prevent the transfer failure caused by blocking phenomenon during copying. The purpose is to provide.

3. Summary of Solution to Invention

The present invention for achieving the above object is "method of mixing the mixed polymerization ratio of methyl methacrylate: butyl acrylate 40 parts by weight to 80 parts by weight: 20 parts by weight to 60 parts by weight and copolymerized using water as a solvent In which the hydroxyethyl methacrylate or acrylic acid alone or a mixture of 1 to 10wt% of the weight of the mixture of methyl methacrylate-butylacrylic acid was added to the reaction mixture and the alkoxy group, the hydroxy group, the amine group, Transparent or translucent polymer is prepared by mixing 5-40 parts by weight of a thermosetting polymer having two or more functional groups selected from an amide group or a water-soluble block isocyanate group with 0.05 to 1.0 parts by weight of a crosslinked polysiloxane. Coating and drying in the film forming process or after the film forming process The offer of the electrophotographic copying overhead projection method for manufacturing.

4. Important uses of the invention

The present invention has use as an overhead projection film for electrophotographic copying.

Description

Overhead projection film for electrophotographic copying and manufacturing method thereof

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to an overhead film for electrophotographic copying and a method for manufacturing the same, and more particularly, to a thermoplastic polymer and a thermosetting polymer having good toner adhesion and coating strength on at least one side of a transparent or translucent polymer film substrate. The present invention relates to an overhead projection film for electrophotographic copying by applying a water-soluble coating solution prepared with a blocking agent or the like to a film substrate, and a method of manufacturing the same.

As is known, a toner image forming process by a conventional electrophotographic copier can be generally divided into five steps as follows.

1. A drum coated with a photoconductive material such as selenium passes through a series of corona discharge cores in the dark room, resulting in positive or negative electrostatic charges on its surface depending on the type of device. .

2. The drum is exposed to the lens with the reproduced image to form an electrostatic latent image in the surface yarn. That is, when the charged drum surface is exposed, the charges on the drum surface portion to which light reaches are scattered through the conductive support, and the charges on the portion where the light does not reach remain intact.

3. On the contrary, when the charged toner particles adhere to the drum surface, the toner particles adhere to the drum surface by the electrostatic attraction in the charged part (image part).

4. When the film containing the image passes between the drum and the transfer corona discharge core, the toner fine particles are transferred from the drum to the film medium.

5. The transferred toner fine particles are fused to the film medium by heat, pressure, or heat and pressure.

There are many types of copiers which can form an image on a transparent or translucent film substrate by using the electrophotographic method of the above method, and the film for copiers of this type basically consists of a film substrate layer and an image receiving layer. Such an image receiving layer requires good adhesion to the toner and a film strength.

In this regard, US Patent No. 3854942 discloses an image receiving layer coating liquid containing a copolymer of acryl and vinyl acetate on a transparent or translucent film substrate to form an image receiving layer, thereby exhibiting an adhesive ability to a toner. Provided is a method for manufacturing an overhead projection film for a photocopier, and US Patent No. 4370379 discloses a method for manufacturing an overhead projection film for an electrophotographic photocopier coated with an image receiving layer coating liquid mixed with an acrylic resin and polyester. However, these prior arts all have limitations in toner adhesion and do not exhibit satisfactory toner adhesion, especially when continuously radiating at high temperatures.

Along with this, US Patent No. 4873135 provides an overhead projection film for an electrophotographic copier in which an image-receiving layer coating solution in which polyvinylacetate and polyester are suitably blended on a film substrate is provided. Not only does not exhibit a certain level of adhesion but also does not show desirable results in the adhesion between the image receiving layer and the film base material, there is a hassle to separate primer treatment on the surface of the image receiving layer and the adhesive surface between the image receiving layer and the film base material. .

In addition, the prior art has to use an organic solvent for dissolving the compound used in the preparation of the image receiving layer coating liquid, and these organic solvents are mostly toxic and flammable, so there is a problem that causes fire hazards and environmental problems during operation. .

In addition to the above problems, an antistatic agent, a slip agent, and other reaction catalysts are added to the coating film forming the image receiving layer of the electrophotographic copier film in addition to the toner accommodating binder resin, which causes a blocking phenomenon between the films. This can cause phenomena such as multi-feeding (a phenomenon in which multiple sheets of film are stacked and conveyed at the same time) or a feeding failure (a phenomenon in which copying is interrupted by the film medium being stuck in a copying machine).

As a conventional technique for preventing such a phenomenon, US Patent No. 3618752 attaches a sheet of paper for smooth transfer of the film during copying, and the sheet of paper is used to solve some of the transfer failures by suppressing charge buildup on the surface of the film. However, there is a problem that causes an increase in production costs and waste of resources.

The present invention is to solve the above problems, an image receiving layer coating liquid prepared by mixing a thermoplastic polymer exhibiting excellent toner adhesion and coating film strength as a water-soluble, a thermosetting polymer and a blocking agent introduced cross-linking structure in the molecule Is applied to at least one side of the transparent or semi-transparent polymer film substrate to solve the environmental problems that occur when using organic solvents and the risk of fire in manufacturing, and to immediately apply the image receiving layer coating liquid in the film substrate forming process without any primer treatment. The purpose of the present invention is to provide an overhead projection film for electrophotographic copying and a method of manufacturing the same, which can greatly reduce manufacturing costs and prevent transfer failure due to blocking during copying.

The present invention for achieving the above object is in the process of copolymerizing the mixed polymerization ratio of methyl methacrylate: butyl acrylate in 40 parts by weight to 80 parts by weight: 20 parts by weight to 60 parts by weight and using water as a solvent A thermoplastic polymer, an alkoxy group, a hydroxy group, an amine group, and an amide group copolymerized by adding hydroxyethyl methacrylate or acrylic acid alone or in a mixture at 1 to 10 wt% of the weight of the mixture of methyl methacrylate-butyl acrylate. Or 5 to 40 parts by weight of a thermosetting polymer having two or more functional groups selected from a water-soluble block isocyanate group and 0.05 to 1.0 parts by weight of a crosslinked polysiloxane and a transparent or semitransparent polymer film substrate. Coating and drying during or after the film forming process Provided is a method for producing an overhead projection film for electrophotographic copying, and an overhead projection film for electrophotographic copying produced thereby.

As the film base material of the present invention, a flexible and thermally stable polymer material should have transparency suitable for use for overhead projection. That is, it must be transparent to visible light and have sufficient thermal stability at 120 to 200 ° C. to withstand image fusion by heat during radiation.

Suitable film base materials for this purpose include polyester, cellulose triacetate, polyimide, polycarbonate polysulfone or polyethylene terephthalate film, but in view of physical properties such as thermal stability, a biaxially oriented polyethylene terephthalate film is used. Preference is given to having a thickness of 50 to 200 μm.

The image receiving layer formed on the surface of the film substrate is also required to be transparent to visible light as well as excellent toner adhesion and good coating strength. In the present invention, the main component of the thermoplastic polymer emulsion used in the preparation of the image receiving layer is methylmetha. As a copolymer of acrylate and butyl acrylate, it has a very good affinity with various toners and has a molecular weight between 50000 and 500000.

In particular, it exhibits excellent adhesion to polyethylene terephthalate, which is most often used as a film base material, so that an image receiving layer can be directly applied to a polymer film base without a separate primer layer, which is methyl methacrylate when forming an image receiving layer coating film. This is because the coating film is held firmly on the film substrate to improve the coating film strength.

On the other hand, in the case of butyl acrylate, it is important to combine the appropriate amount of the above two monomers copolymerization to give the adhesive force to the toner, and when the amount of methyl methacrylate is excessive, the coating film strength is excellent Etoner adhesion is less than the desired level, and even if the amount of butyl acrylate is excessive, the coating film strength is weakened, causing blocking between films during long-term storage or multi-feed during continuous copying. do.

For this reason, the most suitable blending ratio for the copolymerization of the two monomers is to make the mixed polymerization ratio of methyl methacrylate: butyl acrylate as 40 parts by weight to 80 parts by weight: 20 parts by weight to 60 parts by weight, as mentioned above. Preferably, the copolymerization reaction is carried out with a mixed polymerization ratio of methyl methacrylate: butyl acrylate being 50 parts by weight to 60 parts by weight: 40 parts by weight to 50 parts by weight.

The hydroxyethyl methacrylate or acrylic acid added during the copolymerization of methyl methacrylate and butyl acrylate forms a crosslinked structure with a thermosetting polymer to be added later to greatly increase the strength of the coating film and improve the toner adhesion. The addition amount is added to less than 10wt% of the weight of the mixture of methyl methacrylate and butyl acrylate, more preferably 5 to 7wt%.

Since hydroxyethyl methacrylate or acrylic acid added in the present invention is hydrophilic, even when added together with methyl methacrylate and butyl acrylate at the beginning of the copolymerization reaction, the hydroxyethyl methacrylate or acrylic acid is added to the outside of the micelle formed during the reaction and added later. Participation in the cross-linking reaction with the thermosetting polymer may exhibit the effect, but it is more effective because it is advantageous to orient the exterior of the micelle by advancing the reaction at the end of the copolymerization reaction.

The thermosetting polymer added in the present invention should have a structure capable of crosslinking with the above-mentioned thermoplastic emulsion, and the thermosetting polymer may contain at least one of an alkoxy group, a hydroxy group, an amine group, an amide group, or a water-soluble blocked isocyanate group as described above. Compounds containing two or more on the molecular structure are suitable, and examples of such thermosetting polymers include melamine-formaldehyde resins, urea-formaldehyde resins, water-soluble blocked diisocyanate resins, and the like.

The amount of the thermosetting polymer can be appropriately controlled within 5 to 40 parts by weight depending on the molecular weight and the number of functional groups. Particularly, the thermosetting polymer is used to exhibit excellent water solubility and react with the thermoplastic polymer emulsion to form a good crosslinked structure. In the case of melamine-formaldehyde resin, it is more preferable to add 20-25 wt% of the thermoplastic polymer.

In the present invention, a reaction catalyst may be added to further promote the crosslinking reaction between the thermoplastic polymer emulsion and the thermosetting polymer. When a melamine-formaldehyde resin or a urea-formaldehyde resin is used as the thermosetting polymer, an acid or a block acid is used. It is preferable to use and in the case of using a water-soluble blocked diisocyanate resin as the thermosetting polymer, it is more effective to use an organotin compound or an organic manganese compound.

The input amount of the catalyst can be appropriately adjusted according to the film forming condition or drying condition (drying temperature, drying time and ventilation amount), and it is generally preferable to add about 0.01 to 1wt% of the total solid content contained in the image receiving layer coating liquid. In exceptional cases, when the film forming conditions or the drying conditions are severe, the desired crosslinked structure can be obtained by the thermosetting polymer alone even when the catalyst is not used.

In the present invention, the crosslinked polysiloxane added as the blocking agent is composed of a crosslinked structure and introduced into the molecular structure by mixing the multifunctional siloxane monomer during the polymerization process, and the crosslinked polysiloxane thus prepared has the shape of spherical particles and is not easily modified by external force. It has a longitude.

The crosslinked polysiloxane may improve the hardness by heat treatment at a high temperature of 800 ° C. or higher for 1 to 4 hours, but may increase the hardness by increasing the amount of the polyfunctional siloxane monomer in the polymerization process of the crosslinked polysiloxane.

The size of the crosslinked siloxane is suitable for imparting blocking resistance when the diameter is 0.2 to 10 μm. When the amount of the crosslinked siloxane is small, the blocking effect is lowered. When the amount is excessive, the crosslinked siloxane may be applied in the image receiving layer coating process. It is preferable to add 0.05 to 1.0 parts by weight based on the solids content of the image-receiving layer coating liquid because it may cause scratches on the surface of the film.

The image-receiving layer coating liquid prepared by the method described above may be applied onto the polymer film substrate by a conventional method conventionally used. That is, the process of rewinding the wound film substrate before the longitudinal stretching, between the longitudinal stretching and the transverse stretching, between the transverse stretching and the winding of the film substrate, or after the manufacturing process of the film substrate is completed. An image receiving layer may be formed on the film substrate by applying and drying the prepared image receiving layer coating solution at one or both sides of the film substrate at a density of about 0.1 to 2.0 g / m 3.

Hereinafter, the present invention will be described in more detail by the following Examples, Comparative Examples and Experimental Examples.

(Example 1)

Into a four-necked flask equipped with a reflux condenser, a stirrer, a thermometer, and a nitrogen injector, 160 g of deionized water and 6.75 g of sodium lauryl sulfate were added and stirred under a nitrogen atmosphere. The temperature was maintained at 90 ° C., 83 g of methyl methacrylate. Then, 41 g of butyl acrylate, 7 g of hydroxymethyl methacrylate, and 4 g of acrylic acid were separately mixed, and the mixture was added for about 13 minutes using a dropping apparatus, and the flask was kept at a constant temperature by raising the temperature to 90 ° C. 20.25 g of a potassium persulfate 2% aqueous solution was added to the flask over about 30 minutes using a dropping apparatus, and reacted for 4 hours.

In the state where the reaction was terminated by adjusting the amount of deionized water was added to adjust the solid content concentration of the reaction solution to about 40wt% to prepare a thermoplastic reaction solution.

Subsequently, while stirring 868 g of deionized water at room temperature, 0.3 g of a crosslinked siloxane filler having an average particle size of 1.0 μm, 120 g of the prepared thermoplastic polymer reaction solution, 12 g of melamine-formaldehyde resin and 0.08 g of an acid catalyst were added in this order. Was prepared to prepare an image receiving layer coating solution.

(Example 2)

Into a four-necked flask equipped with a reflux condenser, a stirrer, a thermometer, and a nitrogen injector, 160 g of deionized water and 6.75 g of sodium lauryl sulfate were added and stirred under a nitrogen atmosphere. The temperature was maintained at 90 ° C., 83 g of methyl methacrylate. And 41 g of butyl acrylate were separately mixed and then added over a period of about 13 minutes using a dropping device, and then 20.25 g of a potassium persulfate 2% aqueous solution was added dropwise while the flask was kept at a constant temperature by raising the temperature to 90 ° C. Into the flask over about 30 minutes using the apparatus, the reaction passed about 1 hour after the peak of the exothermic reaction, and then mixed 7g of hydroxymethyl methacrylate and 4g of acrylic acid separately and about 15 minutes using the dropping device After adding over 4 g of potassium sulfate 4% aqueous solution was added again over about 7 minutes using a dropping apparatus and reacted for 4 hours.

In the state where the reaction was terminated by adjusting the amount of deionized water was added to adjust the solid content concentration of the reaction solution to about 40wt% to prepare a thermoplastic reaction solution.

Subsequently, while stirring 868 g of deionized water at room temperature, 0.3 g of a cross-linked siloxane filler having an average particle size of 3.2 μm, 120 g of the prepared thermoplastic polymer reaction solution, 12 g of urea-formaldehyde resin and 0.08 g of an acid catalyst were added in this order. Was prepared to prepare an image receiving layer coating solution.

(Example 3)

Into a four-necked flask equipped with a reflux condenser, a stirrer, a thermometer, and a nitrogen injector, 160 g of deionized water and 6.75 g of sodium lauryl sulfate were added and stirred under a nitrogen atmosphere. The temperature was maintained at 90 ° C., 83 g of methyl methacrylate. And 41 g of butyl acrylate were separately mixed and then added over a period of about 13 minutes using a dropping device, and then 20.25 g of a potassium persulfate 2% aqueous solution was added dropwise while the flask was kept at a constant temperature by raising the temperature to 90 ° C. Into the flask over about 30 minutes using the apparatus, the reaction passed about 1 hour after the peak of the exothermic reaction, and then mixed 7g of hydroxymethyl methacrylate and 4g of acrylic acid separately and about 15 minutes using the dropping device After adding over 4 g of potassium persulfate 4% aqueous solution was added again over about 7 minutes using a dropping apparatus and reacted for 4 hours.

In the state where the reaction was terminated by adjusting the amount of deionized water was added to adjust the solid content concentration of the reaction solution to about 40wt% to prepare a thermoplastic reaction solution.

Subsequently, while stirring 868 g of deionized water at room temperature, 0.3 g of a crosslinked siloxane filler having an average particle size of 7.8 μm, 120 g of the prepared thermoplastic polymer reaction solution, 12 g of diisocyanate resin, and 0.08 g of an acid catalyst were added in this order. An image receiving layer coating liquid was prepared.

(Comparative Example 1)

Into a four-necked flask equipped with a reflux condenser, a stirrer, a thermometer, and a nitrogen injection device, 160 g of deionized water and 6.75 g of sodium lauryl sulfate were added, and the mixture was stirred under a nitrogen atmosphere and the temperature was maintained at 90 ° C., 90 g of methyl methacrylate. And 45 g of butyl acrylate were separately mixed and then added over a period of about 13 minutes using a dropping device, and then 20.25 g of a potassium persulfate 2% aqueous solution was added dropwise while the flask was kept at a constant temperature of 90 ° C. The apparatus was put into a flask over about 30 minutes and allowed to react for 4 hours.

In the state where the reaction was terminated by adjusting the amount of deionized water was added to adjust the solid content concentration of the reaction solution to about 40wt% to prepare a thermoplastic reaction solution.

Subsequently, while stirring 868 g of deionized water at room temperature, 120 g of the prepared thermoplastic polymer reaction solution, 12 g of melamine-formaldehyde resin, and 0.08 g of an acid catalyst were added thereto in order to prepare an image receiving layer coating solution.

(Comparative Example 2)

In the same manner as in Example 1, instead of the prepared thermoplastic reaction solution, neocryl bitty-62 (Neocryl BT-62, manufactured by Zeneca) was used, and the silica filler having an average particle size of 0.04 μm as a blocking agent. 0.3 g was used.

(Comparative Example 3)

In the same manner as in Example 3, instead of the prepared thermoplastic reaction solution, AC 503 (AC 503, manufactured by Rohm & Haas) was used, and 0.3 g of a silica filler having an average particle size of 0.1 μm was used as a blocking agent. Used.

Experimental Example

After coating each of the image-receiving layer coating liquid prepared from Examples 1 to 3 and Comparative Examples 1 to 3 with a Mayer bar coating method on a polyethylene terephthalate film (SH71, SKC Co., Ltd.) having a thickness of 100 ㎛, After drying at about 180 ° C. for 2 minutes, an overhead projection film for electrophotographic copying having a dry coating thickness of 0.4 μm was prepared, and each film thus prepared was subjected to toner adhesion, blocking resistance, and poor transfer according to the following test method. After performing the number and coating hardness test results are shown in Table 1 below.

(Toner Adhesion Test Method)

After forming a donor image on the surface of the film with two copiers of Xerox Vivace 500 and 550, the cross-cut area is made by the method proposed in ASTM D3359, adhered to the cellophane tape, and peeled off. After measuring the adhesive force, the result is 4+ for "very good", 4 for "good", 3 for "normal", 2 for "bad" and "very bad" "Is represented by 1.

(Blocking Resistance Test Method)

20 sheets of double-sided coated film are applied and 390kg / ㎡ pressure is applied, heated at 80 ℃ for 48 hours, and the film is removed to observe whether blocking occurs. A case of 5 sheets or less was determined to be "normal" and a case of blocking of 6 or more sheets was "bad".

(Transfer frequency test method)

After continuous copying of 100 films using Xerox's Vivace 550 copying machine at 25 ° C. and 50% relative humidity, the total number of transfers and the fixed number of transfers were recorded.

(Film hardness test method)

Using a regular cotton swab, rub the surface of the film coated with the image-receiving layer several times and record the number of rubs up to the point where the coating film began to peel off.Then, if the number is 5 times or less, ×, 6-10 times, ○, 11 times or more. The case is represented by ◎.

TABLE 1

As can be seen from the results shown in Table 1, in the case of the embodiment according to the present invention, all of the blocking resistance is "good", which shows very good friction resistance, but is less than three cases in the number of poor transfers, but the comparison In all cases, the blocking resistance was very poor, and thus the number of transfer defects due to the blocking phenomenon between films during copying was also 12 to 22, indicating a maximum transfer defect rate of 11 times as compared with the embodiment.

In addition, in the embodiment of the present invention, in the toner adhesive force, a good test result of "excellent" or more was shown, whereas the comparative example showed a test result of the lowest grade overall, and the coating film strength was also very poor.

As described above, the present invention provides a transparent or semi-transparent polymer film-based image-receiving layer coating liquid prepared by mixing a thermoplastic polymer exhibiting excellent toner adhesion and coating film strength as a water-soluble, a thermosetting polymer and a blocking agent having a crosslinked structure in the molecule. By directly coating on at least one side, it is possible not only to solve all the problems in the use of organic solvents, but also to greatly reduce manufacturing costs and to prevent transfer defects due to blocking phenomenon during copying. And it is a useful invention which provides the manufacturing method.

Claims (12)

Methyl methacrylate: butyl acrylate mixed polymerization ratio of 40 parts by weight to 80 parts by weight: 20 parts by weight to 60 parts by weight of hydroxyethyl methacrylate or acrylic acid alone in the process of copolymerization using water as a solvent Or a functionalized polymer selected from an alkoxy group, a hydroxy group, an amine group, an amide group, or a water-soluble block isocyanate group copolymerized by adding a mixture at 1 to 10 wt% of the weight of the mixture of methyl methacrylate-butylacrylate. An image-receiving layer coating solution prepared by mixing 5 to 40 parts by weight of a thermosetting polymer composed of two or more in a molecule with 0.05 to 1.0 parts by weight of a crosslinked polysiloxane is used during or after the film forming process of the transparent or translucent polymer film substrate. Overhead for electrophotographic copying, characterized by coating and drying Method for manufacturing a projection film. The method of claim 1, wherein the mixed polymerization ratio of methyl methacrylate: butyl acrylate is 50 parts by weight to 60 parts by weight: 40 parts by weight to 50 parts by weight. The method for producing an overhead projection film for electrophotographic copying according to claim 1 or 2, wherein the amount of the hydroxyethyl methacrylate or acrylic acid added alone or in a mixture is 5 to 7 parts by weight. The method of claim 3, wherein the thermosetting polymer is melamine-formaldehyde resin, urea-formaldehyde resin or water-soluble blocked diisocyanate resin. 5. The method of claim 4, wherein the film substrate is polyester, polycarbonate, polyimide, polysulfone or cellulose trivinylacetate. 6. The method of claim 5, wherein the average particle size of the crosslinked polysiloxane is 0.2 to 10 [mu] m. Methyl methacrylate: butyl acrylate mixed polymerization ratio of 40 parts by weight to 80 parts by weight: 20 parts by weight to 60 parts by weight of hydroxyethyl methacrylate or acrylic acid alone in the process of copolymerization using water as a solvent Or a functionalized polymer selected from an alkoxy group, a hydroxy group, an amine group, an amide group, or a water-soluble block isocyanate group copolymerized by adding a mixture at 1 to 10 wt% of the weight of the mixture of methyl methacrylate-butylacrylate. An image-receiving layer coating solution prepared by mixing 5 to 40 parts by weight of a thermosetting polymer composed of two or more in a molecule with 0.05 to 1.0 parts by weight of a crosslinked polysiloxane is used during or after the film forming process of the transparent or translucent polymer film substrate. For electrophotographic copying, which is produced by coating and drying Overhead projection film. 8. The overhead projection film for electrophotographic copying according to claim 7, wherein the mixed polymerization ratio of methyl methacrylate: butyl acrylic acid is 50 parts by weight to 60 parts by weight: 40 parts by weight to 50 parts by weight. The overhead projection film for electrophotographic copying according to claim 7 or 8, wherein the amount of hydroxyethyl methacrylate or acrylic acid added alone or in a mixture is 5 to 7 parts by weight. 10. The overhead projection film of claim 9, wherein the thermosetting polymer is melamine-formaldehyde resin, urea-formaldehyde resin or water-soluble blocked diisocyanate resin. 11. The overhead projection film of claim 10, wherein the film substrate is polyester, polycarbonate, polyimide, polysulfone or cellulose trivinylacetate. 12. The overhead projection film of claim 11, wherein the crosslinked polysiloxane has an average particle size of 0.2 to 10 [mu] m.