JP2009291690A - Method of cleaning release film and method of recycling base film and release film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of cleaning a release film which can be easily performed at a low cost, as well as is best-suited for recycling a release film. <P>SOLUTION: This method of cleaning the release film having a base film and a release layer formed on the base film, comprises a cleaning process to clean a foreign substance deposited on the surface of a release layer with a cleaning fluid containing an organic solvent, and a solvent removing process to remove the cleaning fluid deposited on the surface of the release layer. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a peeling film cleaning method, and a substrate film and a peeling film recycling method.

  As a manufacturing process of a multilayer ceramic capacitor, a method of using a dielectric green sheet formed on a release film and peeling the release film to laminate the dielectric green sheet is known.

  The release film used in such a manufacturing process generally has a base film and a release layer formed of a silicone resin on the base film so as to have both desired strength and peelability. . Usually, a small amount of dielectric residue adheres to the release film peeled off from the dielectric green sheet on the surface of the release layer that is in close contact with the dielectric green sheet.

  From the viewpoint of effective use of resources, recycling of release films and substrate films has been studied. In recycling, it is necessary to remove dielectric residues and impurities attached to the release film.

Recycling methods include, for example, a method of finely cutting and cleaning the release film, melting the resin constituting the base film, and then regenerating the base film using a resin raw material, or an easily soluble resin in the release film A technique for facilitating separation of a surface functional layer composed of a silicone resin or the like and a base film by providing a layer has been proposed (for example, Patent Document 1).
JP 2004-169005 A

  However, in the above-described method, it is necessary to separately provide an easily soluble resin layer on the base film, and since it is necessary to melt the base film, the process becomes complicated, and the release film or There has been a problem that it takes time and cost to recycle the base film.

  Therefore, in order to establish a method for easily recycling the release film, the present inventors tried to wash and recycle the used release film without melting the base film, and explained below. As we did, we were not satisfied with the results.

  Foreign substances such as dielectric residues and electrode material residues adhere to the release layer of the release film released from the dielectric green sheet or the electrode green sheet. When such a release film is immersed in the cleaning liquid and then taken out, a portion where the cleaning liquid droplets adhere to the surface of the release layer is generated. Therefore, when the cleaning liquid is dried as it is, the surface tension of the release film is low, and thus the liquid droplets are evaporated while the droplet diameter is reduced. In the cleaning liquid, there are a small amount of impurities derived from the cleaning liquid, and impurities derived from dielectric residues and electrode materials in the cleaning liquid. For this reason, when the cleaning liquid adhering to the surface of the release film is dried as it is, the diameter of the droplets is reduced so as to be contracted to the center according to the evaporation amount, the impurities are concentrated, and finally the foreign matter is removed. It remains in the form of dots (near the center of the original droplet). It has been found that when a dielectric slurry is applied to a release film cleaned by such a method, pinholes are formed in the dielectric layer by foreign matters remaining in the form of dots.

  As another cleaning method for recycling the release film, there is a method of removing a dielectric residue adhered to the surface of the release film using a large amount of ultra-high purity cleaning liquid. However, this method uses a large amount of a cleaning liquid having a high unit price, which leads to an increase in cost and is not preferable from the viewpoint of effective use of resources.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a method for cleaning a release film that can be easily implemented at low cost and is suitable for recycling. Moreover, it aims at providing the recycling method of the peeling film and base film which can be implemented easily at low cost.

  In order to achieve the above object, the present invention provides a cleaning method for a release film having a base film and a release layer formed on the base film, wherein the foreign matter adhering to the surface of the release layer is organically treated. There is provided a cleaning method for a release film having a cleaning step of cleaning with a cleaning liquid containing a solvent and a solvent removing step of removing a cleaning liquid adhering to the surface of the release layer.

  According to the method for cleaning a release film of the present invention, it is possible to easily clean a release film having a foreign substance attached to the release layer at a low cost. The release film cleaned by this cleaning method has a sufficiently reduced amount of foreign matter adhering to the surface. Therefore, when reused as a release film for forming a dielectric green sheet, the pinhole of the dielectric green sheet Can be sufficiently suppressed. Therefore, the cleaning method of the present invention is suitable as a cleaning method for recycling the release film.

  In the method for cleaning a release film of the present invention, in the solvent removal step, it is preferable to remove the cleaning solution by blowing a gas to the cleaning solution attached to the surface of the release layer. As a result, the release film can be easily washed at a lower cost.

  In the method for cleaning a release film of the present invention, it is preferable that the cleaning liquid adhering to the surface of the release layer is absorbed and removed by fibers in the solvent removal step. As a result, the solvent attached to the surface of the release layer of the release film can be removed more reliably, and when it is reused as a release film for forming the dielectric green sheet, pinholes in the dielectric green sheet are generated. It can suppress more fully.

  It is preferable that the cleaning method for a release film of the present invention includes an adhesive step in which the surface of the release layer and the adhesive roll are brought into contact with each other to remove a part of the foreign matter attached to the surface before the cleaning step. Accordingly, since the dielectric adhered to the surface of the release layer can be removed to some extent before the solvent removal step, the amount of foreign matter on the surface of the release layer after cleaning can be further sufficiently reduced.

  This invention also provides the recycling method of the peeling film which recycles the peeling film wash | cleaned with the said washing | cleaning method.

  The present invention is also a method for cleaning a release film having a base film and a release layer formed on the base film, wherein the release film having a foreign substance in the release layer includes an alkaline substance and alcohol. Provided is a peeling film cleaning method having a removing step of removing a release layer from a base film by contacting with a solution and then contacting with an organic solvent.

  According to the cleaning method, a release film having foreign matter on the surface or inside of the release layer can be easily cleaned. The reason for this is as follows. First, by bringing the release layer into contact with a solution containing an alkaline substance and alcohol, the siloxane bond or the like of the silicone resin constituting the release layer can be cut. And a peeling layer can be easily removed from a base film by making the silicone resin etc. which became low molecular weight by cutting | disconnection of a bond contact an organic solvent.

  In this invention, it has the process of giving a corona treatment to a peeling layer before a removal process, and it is preferable that the solution which contacts a peeling film at a removal process contains water. Thus, the surface of the release layer can be made hydrophilic, and the penetration of the alkaline substance into the release layer can be facilitated even if a solution containing water is used in the removal step. Since the alkaline substance can be easily dissolved in the solution containing water, the siloxane bond or the like can be cut more smoothly.

  Moreover, in this invention, the recycling method of the peeling film which has a peeling layer formation process which forms a peeling layer on one surface of the base film from which the peeling layer was removed by the above-mentioned washing | cleaning method is provided. According to this recycling method, it is possible to regenerate a release film in which foreign matter on the surface is sufficiently removed and the generation of pinholes can be sufficiently suppressed when a dielectric green sheet is formed on the release layer.

  Further, in the present invention, a base film having a release layer formed on one surface and foreign matter attached on the release layer is contacted with a solution containing an alkaline substance and alcohol, and then contacted with an organic solvent. And providing a recycling method of the base film having a removing step of removing the foreign matter and the release layer from the base film. This makes it possible to easily recycle the base film at a low cost.

  According to the present invention, it is possible to provide a method for cleaning a release film that can be easily implemented at low cost and is suitable for recycling. Moreover, the recycling method of the peeling film and base film which can be implemented easily at low cost can be provided.

  In the following, preferred embodiments of the present invention will be described with reference to the drawings as the case may be. In the description of the drawings, the same reference numerals are used for the same or equivalent elements, and duplicate descriptions are omitted.

(First embodiment)
FIG. 1 is a side view schematically showing an example of a release film used in the cleaning method of the present invention.

  The release film 10 includes a base film 12 and a release layer 14 formed on one surface of the base film 12. In addition, foreign matter 16 is attached on the surface of the release layer 14. First, the base film 12 and the release layer 14 will be described below.

Examples of the base film 12 include a polyester film. For applications requiring transparency, it is preferable to use a polyester film having high transparency, and a biaxially stretched polyester film is particularly preferable. Further, in applications where shielding is required, preferably a polyester film obtained by blending an inorganic pigment, TiO _2, biaxially oriented polyester film such pigment was compounded as SiO ₂ or the like is particularly preferred.

  The polyester constituting the polyester film is preferably a crystalline linear saturated polyester comprising an aromatic dibasic acid component and a diol component. For example, polyethylene terephthalate (PET), polypropylene terephthalate, polybutylene terephthalate, polyethylene- Examples include 2,6-naphthalate.

  The polyester film in the present embodiment can be produced by a conventionally known method. For example, the biaxially stretched polyester film is obtained by drying the polyester, melting it in an extruder, extruding it from a die (for example, T-die, I-die, etc.) onto a rotating cooling drum, quenching it into an unstretched film, This unstretched film can be produced by stretching in a biaxial direction and heat-setting as required.

  Although the thickness in particular of the base film 12 is not restrict | limited, 5-250 micrometers is preferable. This makes it possible to achieve both the peelability from the dielectric green sheet and the mechanical strength.

  It is preferable that the peeling layer 14 contains a silicone resin (silicone cured product). Thus, the release layer 14 having excellent peelability can be obtained, and the amount of dielectric residue remaining on the surface 10a of the release layer 14 after the dielectric green sheet is removed can be reduced.

  The peeling layer formation process which forms the peeling layer 14 on one surface of the base film 12 is demonstrated below. As the release agent liquid that can be used for forming the release layer 14, a coating liquid containing a curable silicone resin can be used. The release layer 14 can be formed by applying a coating liquid containing a curable silicone resin, followed by drying and curing.

  The curable silicone resin is not particularly limited, and for example, any of a condensation reaction type, an addition reaction type, an ultraviolet curable type, an electron beam curable type, and the like can be used. Specific examples include KS-774, KS-775, KS-778, KS-779H, KS-856, X-62-2422, X-62-2461, KNS-305, KNS- manufactured by Shin-Etsu Chemical Co., Ltd. 3000, X-62-1256, DKQ3-202, DKQ3-203, DKQ3-204, DKQ3-205, DKQ3-210, manufactured by Dow Corning Asia, YSR-3022, TPR-6700, TPR-6700, manufactured by Toshiba Silicone -6720, TPR-6721, etc., SD7223, SD7226, SD7229, SRX-210 manufactured by Toray Dow Corning Silicone.

  As a method for coating the curable silicone resin paint, known methods such as a reverse roll coating method, a gravure roll coating method, and an air knife coating method can be employed.

  The applied curable silicone resin paint can form a cured film by, for example, drying and curing with heat. In that case, it is preferable to form a cured film by performing heat treatment at a temperature in the range of 50 to 180 ° C., preferably 80 to 160 ° C. for 5 seconds or longer, preferably 10 seconds or longer. In the case of the ultraviolet curable type and the electron beam curable type, after the silicone resin paint is applied, the coating surface is cured by irradiating the application surface with ultraviolet rays and an electron beam, respectively.

The coating thickness of the curable silicone resin is preferably 0.01 to 25 g / m ² , more preferably 0.05 to 20 g / m ² .

  The thickness of the release layer 14 is preferably 0.03 to 5 μm, and more preferably 0.05 to 3 μm. When the thickness of the release layer 14 is less than 0.05 μm, the release performance of the release layer tends to decrease. On the other hand, when the thickness of the release layer 14 exceeds 3 μm, the curing of the coating liquid tends to be insufficient, and the release performance may change over time.

  A ceramic coating containing ceramic powder, an organic binder, a plasticizer, a solvent, etc. is applied to the surface 10a on the release layer 14 side of the release film 10 thus obtained by a doctor blade method or the like, and a dielectric green sheet Can be formed. Moreover, an electrode pattern can be formed on the surface 10a of the release film 10 by screen printing an electrode paste containing palladium, silver, nickel or the like. When the dielectric green sheet or the electrode pattern is peeled from the release film 10, the foreign matter 16 usually adheres to the surface 10 a of the release layer 14 of the release film 10.

  Examples of the foreign material 16 include a residue of dielectric material and electrode material, dust, and the like. The dielectric residue is derived from the dielectric green sheet formed on the surface 10a of the release film 10, and its component is equivalent to that of the dielectric green sheet.

  The electrode material residue is derived from electrode components such as palladium, silver, and nickel that have been formed on the above-described dielectric green sheet by screen printing. In addition, examples of the foreign material 16 include dust in the air.

  FIG. 2 is a process diagram showing the first embodiment according to the method for cleaning a release film of the present invention.

  The method for cleaning the release film 10 of the present embodiment includes a cleaning process for removing foreign matter adhering to the surface 10a of the release film 10 with a cleaning liquid containing an organic solvent, and blowing air to the cleaning liquid on the surface 10a of the release film 10. And a solvent removal step of removing the cleaning liquid.

  In the cleaning process, the release film 10 with the foreign matter adhering to the surface 10a is immersed in the cleaning liquid stored in the cleaning tank 20. As a result, the residue of the dielectric or electrode material swells and stress is generated at the interface between the surface 10a of the release film 10 and the residue, and the dielectric residue is removed from the surface 10a of the release film 10. Moreover, the dust adhering to the surface 10a is easily removed by immersing the release film in the cleaning liquid.

  The organic solvent contained in the cleaning liquid is not particularly limited as long as it swells and dissolves the residue of the dielectric and electrode material. Examples of the organic solvent include alcohols and ketones. More specifically, methanol, ethanol, propanol, cyclohexanone, methyl isobutyl ketone, methyl ethyl ketone and the like can be mentioned. One of the exemplified organic solvents can be used alone or in combination of two or more.

  While the release film 10 is immersed in the cleaning liquid, ultrasonic vibration having a frequency of about 10 to 100 kHz may be applied to the cleaning liquid. As a result, the dielectric residue can be more reliably removed from the surface 10a of the release film 10. The cleaning liquid may be used at room temperature or heated to a temperature below the boiling point of the cleaning liquid.

  In the solvent removal step, as shown in FIG. 2, air is blown to the cleaning liquid 22 adhering to the surface 10a of the release film 10 while taking the release film 10 upward from the cleaning tank 20 (in the direction of arrow C in FIG. 2). To remove the cleaning liquid 22. Although there is no restriction | limiting in particular in the blowing direction of air, It is preferable to blow toward the downward direction (arrow A direction in FIG. 2). Accordingly, the droplet-like cleaning liquid 22 can be moved downward more smoothly and removed from the release film 10 by the action of wind pressure and the action of gravity. Further, since the removed cleaning liquid 22 returns to the cleaning tank 20, the consumption of the cleaning liquid 22 can be suppressed.

  The gas sprayed onto the droplet-like cleaning liquid 22 is not limited to air, and for example, an inert gas such as nitrogen gas or carbon dioxide gas, oxygen gas, or the like may be used. Moreover, a normal commercially available blower can be used as the gas supply source. Using such a blower, for example, the cleaning liquid 22 can be removed by spraying a gas onto the droplet-shaped cleaning liquid 22 attached to the surface 10a of the release film 10 at a wind speed of 5 to 50 m / s.

  According to the cleaning method for the release film 10 of the present embodiment, the droplet-like cleaning liquid 22 can be sufficiently removed from the release film 10 by spraying gas. Therefore, when a dielectric green sheet is formed again on the release layer of the release film 10 after washing, the generation of pinholes can be sufficiently suppressed. For this reason, it is particularly suitable as a cleaning method for recycling the release film for laminating dielectric green sheets.

(Second Embodiment)
FIG. 3 is a process diagram showing a second embodiment according to the method for cleaning a release film of the present invention. In the present embodiment, the cleaning process is performed in the same manner as in the first embodiment. Then, a solvent removal process is performed as follows.

  In the solvent removal process of the present embodiment, the droplet-shaped cleaning liquid 22 attached on the surface 10a of the release film 10 taken out from the cleaning tank 20 is blown into the horizontal direction by blowing air from the side surface of the release film 10 to the cleaning liquid 22. It is removed by moving in the direction of arrow A in FIG.

  Since the release layer of the release film 10 usually has a low surface tension, the cleaning liquid 22 can be sufficiently removed by blowing air in the horizontal direction as described above. If the release film 10 is tilted so that the leeward side surface of the release film 10 is on the lower side, the cleaning liquid 22 can be more sufficiently removed by the synergistic effect of the action of gravity and the wind pressure of air.

(Third embodiment)
FIG. 4 is a process diagram showing a third embodiment according to the method for cleaning a release film of the present invention. As a whole, the release film 10 is unwound from the roller 30 and taken up by the roller 38, thereby moving in the direction of arrow D and continuously washed.

  The method for cleaning the release film 10 of the present embodiment includes a cleaning process for removing foreign matter adhering to the surface of the release film 10 with a cleaning liquid containing an organic solvent, and blowing air to the cleaning liquid on the surface of the release film 10. It has the 1st solvent removal process which removes a washing | cleaning liquid, the 2nd solvent removal process which adsorbs and removes the washing | cleaning liquid on the surface of the peeling film 10 with a fiber, and the drying process which dries the peeling film 10. FIG.

  In the cleaning step, the release film 10 with the foreign matter 16 attached to the surface is drawn out from the roller 30 and immersed in the cleaning liquid in the cleaning tank 20. Here, the release film 10 is immersed in the cleaning liquid for a predetermined time, and most of the foreign matter 16 such as a dielectric adhered to the release film 10 is removed.

  The organic solvent contained in the cleaning liquid is not particularly limited as long as it swells and dissolves the dielectric residue. Examples of the organic solvent include alcohols and ketones. More specifically, methanol, ethanol, propanol, cyclohexanone, methyl isobutyl ketone, methyl ethyl ketone and the like can be mentioned. One of the exemplified organic solvents can be used alone or in combination of two or more.

  In the first solvent removal step, the release film 10 that has passed through the roller 32 is pulled up from the cleaning tank 20, and the droplet-like cleaning liquid adhering to the surface of the release film 10 is removed by blowing gas. The gas is blown from the blower 24 toward the release film 10. The gas blowing direction can be the same as in the first embodiment or the second embodiment.

  In the second solvent removal step, the release film 10 that has passed through the roller 33 is brought into contact with the fibers 26. The cleaning liquid remaining on the surface of the release film 10 is wiped off by the fibers 26. As the fiber 26, a material having excellent cleaning liquid absorbability can be used. For example, a nonwoven fabric can be used.

  In the present embodiment, the pair of fibers 26 are pressed from above and below the release film 10 so as to sandwich the release film 10. Thereby, the cleaning liquid remaining on the surface of the release film 10 can be more reliably absorbed and removed.

  In the drying step, the release film 10 that has passed through the roller 34 is introduced into the dryer 52 to evaporate the remaining cleaning liquid. As a result, it is possible to obtain a recycled release film in which the amount of residue attached is further sufficiently reduced. Such a release film is rolled by a roller 38 and recycled, for example.

  In the present embodiment, the two solvent removal steps, the first solvent removal step and the second solvent removal step, are provided, but only one of them may be used. Moreover, the adhesion removal process which removes the foreign material adhering on the surface of the peeling layer of a peeling film by making this adhesion layer and the peeling layer of a peeling film contact before using the adhesion roll which has an adhesion layer You may have. By having the adhesion removing step, foreign substances in the finally obtained release film can be more reliably reduced. A commercially available roll can be used as the adhesive roll.

(Fourth embodiment)
The method for cleaning a release film of the present embodiment is a method in which a release film having foreign matters in a release layer is immersed in a decomposition solution obtained by dissolving an alkaline substance in alcohol, and then the release film is contacted with an organic solvent to release the release film. A removal step of removing the layer from the substrate film. Details will be described below.

  As the decomposition solution, a solution in which an alkaline substance is dissolved in alcohol or a mixed solution of alcohol and water can be used. When such a decomposition solution is brought into contact with the release film, a part of the silicone resin constituting the release layer 14 of the release film 10 (FIG. 1) is decomposed. That is, the molecular weight of the silicone resin can be reduced by cutting part of the bond of the silicone resin having a large molecular weight. Moreover, a foreign material can also be removed by immersing the peeling film 10 in a decomposition solution.

  Examples of the alkaline substance include lithium hydroxide, sodium hydroxide, potassium hydroxide and the like. Among these, potassium hydroxide is preferable. The content of the alkaline substance in the decomposition solution is preferably 0.1 to 10 mol / l, and more preferably 0.2 to 2 mol / l. When the content is too high, the base film 12 tends to be damaged, and when the content is too low, the silicone resin tends to take a long time to decompose.

  The mixed solution used for the decomposition solution is preferably a mixed solution of alcohol and water. By using a mixed solution containing water, the alkaline substance can be easily dissolved, and the removal step can be performed smoothly.

  As alcohol, what can melt | dissolve an alkaline substance by alcohol simple substance, or can dissolve an alkaline substance by mixing with water can be used. Of these alcohols, methanol, ethanol, propanol and the like are preferable, lower alcohols such as methanol and ethanol are more preferable, and methanol is more preferable.

  In the case of using a mixed liquid of alcohol and water, the ratio of the alcohol to the whole mixed liquid is preferably 30% by mass or more, more preferably 40% by mass or more, and further preferably 50% by mass or more. preferable. When the proportion of alcohol is less than 30% by mass, the silicone resin has a property of repelling moisture, so that the decomposition of the silicone resin tends to hardly proceed. If the alcohol content is 50% by mass or more, the permeability to the silicone resin can be further improved, and the decomposition of the silicone resin can proceed efficiently.

  It is also preferable that the temperature of the decomposition liquid is heated to, for example, 40 ° C. or higher and the boiling point or lower. Thereby, the decomposition of the silicone resin is promoted, and the removal process can be shortened. The immersion time of the release film 10 in the decomposition solution is not particularly limited, and can be, for example, 30 seconds to 30 minutes.

  As described above, after the release film 10 is immersed in the decomposition solution, the release film 10 is taken out and immersed in an organic solvent. Since the silicone resin of the release layer 14 is decomposed and the molecular weight is reduced by immersion in the decomposition solution, when the release film 10 is immersed in an organic solvent, the release layer 14 dissolves and swells, and the base film 12 Easy to peel off. Even if the release film 10 is directly immersed in an organic solvent without being immersed in the decomposition solution, the release layer 14 cannot be released from the base film 12.

  As the organic solvent, toluene, xylene, benzene, n-hexane, n-heptane, cyclohexane, dimethyl ether, diisopropyl ether, hexyl ether, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, butyl acetate, amyl acetate, and the like can be used. Of these, toluene is preferable from the viewpoint of more easily peeling the release layer 14.

  The temperature of the organic solvent in which the release film 10 is immersed may be room temperature, but is preferably heated to 40 to 60 ° C. Thereby, the swelling of the release layer 14 proceeds more smoothly, and the removal process can be shortened. The immersion time of the release film 10 in the organic solvent is not particularly limited, and can be, for example, 30 seconds to 30 minutes. Moreover, it is preferable to apply ultrasonic vibration to the organic solvent. Thereby, the peeling layer 14 can be peeled from the base film 12 more easily.

  For example, two washing tanks are prepared for the immersion of the organic solvent. First, the release film is immersed in the first cleaning tank, and the release film is pulled up after a predetermined time, and then the release film is subjected to the second cleaning. You may immerse in a tank. Since the content of the silicone component of the organic solvent stored in the second cleaning tank is sufficiently smaller than the content of the silicone component of the organic solvent stored in the first cleaning tank, the silicone component derived from the silicone resin It is possible to obtain a base film having much less adhesion.

  In addition, you may give a corona treatment to the peeling layer surface of a peeling film, before immersing the peeling film to which the residue adhered in the separation liquid. Thus, by providing the process which performs a corona treatment, the peeling layer surface of a peeling film can be made hydrophilic. This makes it easier for the hydrophilic decomposition solution to penetrate into the release layer, and the time required for the removal step can be further shortened.

  After immersing the release film in an organic solvent for a predetermined time and then taking it out of the organic solvent, the base film 12 in which the remaining amount of the release layer is sufficiently reduced can be obtained. Thereby, the base film 12 can be recycled. Since such a base film 12 has a sufficiently reduced amount of foreign matters such as dielectric residues, by performing the above-described release layer forming step of forming a release layer on the base film 12, For example, it can be recycled as a release film for laminating dielectric green sheets. For this reason, it can be said that the method of this embodiment is a removal method of a peeling layer especially suitable as a recycling method of the peeling film for dielectric material green sheet lamination | stacking, and can also be said to be a recycling method of a base film. In the dielectric green sheet formed using the release film cleaned and recycled by the above method, the generation of pinholes is sufficiently suppressed. In addition, damage to the recycled base film is sufficiently suppressed, and the durability is excellent.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment.

  EXAMPLES Hereinafter, although this invention is demonstrated further more concretely based on an Example and a comparative example, this invention is not limited to a following example at all.

(Example 1)
<Preparation of release film>
After adjusting the thermosetting type silicone resin solution to be added and reacted by adding a platinum catalyst to a mixed solution of methyl vinyl polysiloxane having vinyl group and methyl hydrogen silane with toluene, the solid content concentration is adjusted to 3% by mass. It is applied to a 38 μm thick biaxially stretched polyethylene terephthalate (PET) film (base film) with a bar coater so that the coating thickness after drying is 0.1 μm, and dried and cured at a heating temperature of 110 ° C. for 40 seconds. It was made to react and the peeling film in which the silicone resin layer (peeling layer) was formed on the base film was obtained.

<Production of dielectric green sheet>
BaTiO ₃ system ceramic powder, polyvinyl butyral (PVB) as an organic binder, and methanol as a solvent were prepared. Next, 10 parts by weight of an organic binder and 150 parts by weight of a solvent were kneaded with a ball mill to form a dielectric paste with respect to 100 parts by weight of the ceramic powder. This dielectric paste is composed of an organic solvent-based paste obtained by kneading a dielectric material (ceramic powder) and an organic vehicle.

  On the silicone resin layer of the release film produced as described above, the dielectric paste was applied at a predetermined thickness by the doctor blade method and dried to form a dielectric green sheet having a thickness of 1 μm on the release film.

<Preparation of conductor paste>
First, Ni particles having an average particle size of 0.2 μm as the conductive powder and the organic vehicle were prepared. Next, 30 to 70 parts by mass of an organic vehicle was added to 100 parts by mass of the conductive powder, kneaded with a ball mill, and slurried to obtain a conductive paste.

  The produced conductive paste was applied onto a dielectric green sheet formed on a release film to produce an electrode pattern.

  The dielectric green sheet on which the electrode pattern was formed was peeled from the release film to obtain a release film in which a dielectric residue adhered to the surface of the release layer. The release film was immersed in a cleaning tank having cyclohexanone (cleaning liquid) for 1 minute. After immersion, the release film was taken out from the washing tank, and air was blown from the side surface of the release film to remove cyclohexanone adhering to the surface of the release film. After removal, it was visually confirmed that there was no dielectric on the surface of the release layer of the release film. Thereafter, the release film was heated using an infrared heater, and the cyclohexanone on the surface of the PET film opposite to the surface on which the release layer was formed was dried.

  After drying, on the release layer of the washed release film, the above-mentioned dielectric slurry was applied at a predetermined thickness by the doctor blade method and dried to form a dielectric green sheet having a thickness of 1 μm. No pinhole was generated in the dielectric green sheet.

(Example 2)
In the same manner as in Example 1, a release film having a dielectric residue adhered on the surface of the release layer was obtained. The release film was immersed in a washing tank having methyl ethyl ketone for 1 minute. After the immersion, the release film was taken out from the washing tank, and the roll on which the nonwoven fabric placed at a height of 50 cm from the liquid level of the washing tank was wound was brought into contact with the release layer of the release film. Thus, the washing | cleaning liquid on a peeling layer was removed by making the nonwoven fabric absorb the methyl ethyl ketone adhering to the peeling layer surface. After removal, it was visually confirmed that there was no dielectric on the surface of the release layer of the release film. Thereafter, the release film was dried at room temperature.

  After drying, a dielectric slurry was applied and dried on the release layer of the washed release film in the same manner as in Example 1 to form a dielectric green sheet having a thickness of 1 μm. No pinhole was generated in the dielectric green sheet.

(Comparative Example 1)
In the same manner as in Example 1, a release film having a dielectric residue adhered on the surface of the release layer was obtained. The release film was immersed in a cleaning tank having cyclohexanone (cleaning liquid) for 1 minute. After soaking, remove the release film from the washing tank, heat the release film directly using an infrared heater without blowing air, and dry the cyclohexanone on the side of the PET film opposite to the side where the release layer is formed. I let you.

  After drying, a dielectric slurry was applied and dried on the release layer of the washed release film in the same manner as in Example 1 to form a dielectric green sheet having a thickness of 1 μm. Pinholes were generated in the dielectric green sheet.

(Comparative Example 2)
In the same manner as in Example 1, a release film having a dielectric residue adhered on the surface of the release layer was obtained. The release film was immersed in a washing tank having methyl ethyl ketone for 1 minute. After immersion, the release film was dried as it was at room temperature.

  After drying, a dielectric slurry was applied and dried on the release layer of the washed release film in the same manner as in Example 1 to form a dielectric green sheet having a thickness of 1 μm. Pinholes were generated in the dielectric green sheet.

(Example 3)
In the same manner as in Example 1, a release film having a dielectric residue adhered on the surface of the release layer was obtained. The release film was immersed for 1 minute in a decomposition solution (60 ° C.) obtained by mixing 100 parts by mass of pure water and 5 parts by mass of potassium hydroxide with respect to 100 parts by mass of ethanol. After immersion, the release film was taken out of the decomposition solution, washed with pure water, and the decomposition solution was washed away.

  At this point, the release film had a release layer. However, when the magic ink was applied to the surface of the release layer, it was confirmed that the magic ink was not repelled and the repellency was lost.

  Thereafter, the release film was immersed in toluene at room temperature for 1 minute, and the release film was taken out from toluene and dried at room temperature.

  It was confirmed that the release layer and foreign matters were sufficiently removed from the release film, and only the PET film was formed. On this PET film, a silicone resin solution was applied in the same manner as in Example 1 to form a silicone resin layer (release layer), and a release film was obtained.

  On the release layer of this release film, a dielectric slurry was applied and dried in the same manner as in Example 1 to form a dielectric green sheet having a thickness of 1 μm. No pinhole was generated in the dielectric green sheet.

Example 4
In the same manner as in Example 1, a release film having a dielectric residue adhered on the surface of the release layer was obtained. The release film was immersed in a decomposition solution (about 25 ° C.) obtained by mixing 100 parts by mass of ethanol with 100 parts by mass of pure water and 20 parts by mass of potassium hydroxide for 1 minute. After immersion, the release film was taken out from the decomposition solution, washed with pure water, and the decomposition solution was washed away.

  At this point, the release film had a release layer. However, when the magic ink was applied to the surface of the release layer, it was confirmed that the magic ink was not repelled and the repellency was lost.

  Thereafter, the release film was immersed in xylene at room temperature for 1 minute, and the release film was taken out from xylene and dried at room temperature.

  It was confirmed that the release layer and foreign matters were sufficiently removed from the release film, and only the PET film was formed. A silicone resin solution was applied to this PET film in the same manner as in Example 1 to form a silicone resin layer (release layer), and a release film was obtained.

  On the release layer of this release film, a dielectric slurry was applied and dried in the same manner as in Example 1 to form a dielectric green sheet having a thickness of 1 μm. No pinhole was generated in the dielectric green sheet.

(Example 5)
In the same manner as in Example 1, a release film having a dielectric residue adhered on the surface of the release layer was obtained. The release layer surface of the release film was subjected to corona treatment (current amount 5A). The contact angle of pure water on the surface of the release layer after the corona treatment was 86 °, and it was confirmed that the contact angle was more hydrophilic than that before the treatment (contact angle 109 °).

  The release film subjected to corona treatment is immersed for 1 minute in a normal temperature (about 25 ° C.) decomposition solution obtained by mixing 100 parts by mass of ethanol with 100 parts by mass of pure water and 10 parts by mass of potassium hydroxide. did. After immersion, the release film was taken out from the decomposition solution, and the release film was washed with pure water to wash away the decomposition solution.

  At this point, the release film had a release layer. However, when the magic ink was applied to the surface of the release layer, it was confirmed that the magic ink was not repelled and the repellency was lost.

  Thereafter, the release film was immersed in methyl ethyl ketone at room temperature for 1 minute. Thereafter, the release film was taken out of methyl ethyl ketone and dried at room temperature.

  From the release film, it was confirmed that the release layer was completely removed and only the PET film was formed. A silicone resin solution was applied to this PET film in the same manner as in Example 1 to form a silicone resin layer (release layer), and a release film was obtained.

  On the release layer of this release film, a dielectric slurry was applied and dried in the same manner as in Example 1 to form a dielectric green sheet having a thickness of 1 μm. No pinhole was generated in the dielectric green sheet.

(Comparative Example 3)
In the same manner as in Example 1, a release film having a dielectric residue adhered on the surface of the release layer was obtained. The release film was immersed in toluene at room temperature for 2 minutes. Thereafter, the release film was taken out from toluene and dried at room temperature.

  Even when the above treatment was performed, the release layer could not be removed from the release film, and the PET film and the release layer were in close contact.

(Comparative Example 4)
In the same manner as in Example 1, a release film having a dielectric residue adhered on the surface of the release layer was obtained. The release film was immersed for 1 minute in a decomposition solution (60 ° C.) obtained by mixing 5 parts by mass of potassium hydroxide with 200 parts by mass of pure water. After immersion, the release film was taken out from the decomposition solution, and the release film was washed with pure water to wash away the decomposition solution.

  At this point, the release film had a release layer. When the magic ink was applied to the surface of the release layer, it was confirmed that the magic ink was repelled because it was repelled.

  Thereafter, the release film was immersed in toluene at room temperature for 1 minute, and the release film was taken out from toluene and dried at room temperature.

  Even when the above treatment was performed, the release layer could not be removed from the release film, and the PET film and the release layer were in close contact.

It is a side view which shows typically an example of the peeling film used for the washing | cleaning method of this invention. It is process drawing which shows 1st Embodiment which concerns on the cleaning method of the peeling film of this invention. It is process drawing which shows 2nd Embodiment which concerns on the cleaning method of the peeling film of this invention. It is process drawing which shows 3rd Embodiment which concerns on the cleaning method of the peeling film of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Release film, 10a ... Surface, 12 ... Base film, 14 ... Release layer, 16 ... Foreign material, 20 ... Cleaning tank, 24 ... Blower, 26 ... Fiber, 52 ... Dryer.

Claims (9)

A method for cleaning a release film comprising a base film, and a release layer formed on the base film,
A cleaning step of cleaning the foreign matter attached to the surface of the release layer with a cleaning liquid containing an organic solvent,
A solvent removal step of removing the cleaning liquid adhering to the surface of the release layer.   The said solvent removal process is a cleaning method of the peeling film of Claim 1 which removes the said washing | cleaning liquid by spraying gas on the said washing | cleaning liquid adhering to the said surface of the said peeling layer.   The method for cleaning a release film according to claim 1, wherein the solvent removing step absorbs and removes the cleaning liquid adhering to the surface of the release layer with a fiber.   4. The method according to claim 1, further comprising a step of removing a part of the foreign matter attached to the surface by bringing the surface of the release layer into contact with an adhesive roll before the cleaning step. Method for cleaning the release film.   The recycling method of the peeling film which recycles the said peeling film wash | cleaned with the washing | cleaning method as described in any one of Claims 1-4. A method for cleaning a release film comprising a base film, and a release layer formed on the base film,
The peeling film which has the removal process which makes the said peeling film which contacts the organic solvent after making the said peeling film which has a foreign material in the said peeling layer contact the solution containing an alkaline substance, and removing the said peeling layer from the said base film. Cleaning method.   The cleaning method for a release film according to claim 6, further comprising a step of subjecting the release layer to corona treatment before the removal step, wherein the solution that contacts the release film in the removal step contains water.   The recycling method of a peeling film which has a peeling layer formation process which forms a peeling layer on one surface of the said base film from which the said peeling layer was removed by the washing | cleaning method of Claim 6 or 7.   A substrate film having a release layer formed on one surface and foreign matter adhering to the surface of the release layer is brought into contact with a solution containing an alkaline substance and alcohol, and then brought into contact with an organic solvent, whereby the foreign matter And the recycling method of the base film which has the removal process which removes the said peeling layer from the said base film.

Images