CN115298783A

CN115298783A - Release film roll, ceramic member sheet and method for producing same, and ceramic member and method for producing same

Info

Publication number: CN115298783A
Application number: CN202180021509.2A
Authority: CN
Inventors: 饭岛忠良; 江守泰彦; 饭田修治
Original assignee: TDK Corp
Current assignee: TDK Corp
Priority date: 2020-03-18
Filing date: 2021-02-26
Publication date: 2022-11-04
Anticipated expiration: 2041-02-26
Also published as: CN115298783B; TWI778531B; JPWO2021187060A1; KR20220143133A; JP7447988B2; WO2021187060A1; TW202138196A

Abstract

The disclosed release film roll has: a release film having a base film and a release layer; and a winding core around which the release film is wound. When the distance r [ mm ] from the outer peripheral surface of the winding core in the radial direction of the side surface of the release film roll is 10-130 mm, the rebound hardness K (r) [ HL ] measured toward the center of the winding core on the surface of the release film exposed on the outer peripheral surface of the roll satisfies the following formula (1). K (r) is less than or equal to-1.25r +862.5 … (1) and is less than or equal to-2r + 670.

Description

Release film roll, ceramic member sheet and method for producing same, and ceramic member and method for producing same

Technical Field

The present disclosure relates to a release film roll, a ceramic member sheet and a method for manufacturing the same, and a ceramic member and a method for manufacturing the same.

Background

In recent years, electronic components have become more and more miniaturized as electronic devices are required to be miniaturized. Ceramic components, which are one type of electronic components, are also becoming smaller year by year. For example, a multilayer ceramic capacitor, which is one of ceramic components, is intended to increase the capacitance by reducing the thickness of a dielectric layer and an internal electrode. A general multilayer ceramic capacitor is manufactured by forming a dielectric layer and internal electrodes on a carrier film using a release film as a carrier film to prepare a green sheet, and then peeling the green sheet and laminating the green sheets.

When the dielectric layers of the multilayer ceramic capacitor are made thin, the withstand voltage performance, which is the resistance under voltage strength and indicates that a failure such as a short circuit occurs, tends to be lowered. In particular, when the dielectric layer has a non-uniform thickness, the thin portion becomes a factor of lowering the withstand voltage performance. A laminated ceramic capacitor including a dielectric layer having such a thin portion has a withstand voltage failure, and the yield of the laminated ceramic capacitor is reduced. On the other hand, if the dielectric layer has a uniform thickness, the withstand voltage performance is good, and the yield of the laminated ceramic capacitor is improved.

Damage and the like in a release film used as a carrier film for the dielectric layer become factors in thickness variation of the dielectric layer. In addition, the smoothness of the surface of the release film affects the thickness uniformity of the dielectric layer. In view of such a situation, for example, patent document 1 discusses a roll of release film capable of smoothing the release film to reduce the thickness variation of the dielectric layer.

Documents of the prior art

Patent literature

Patent document 1: japanese patent laid-open publication No. 2011-206995

Disclosure of Invention

Technical problem to be solved by the invention

In the step of manufacturing the ceramic member, a ceramic green sheet is formed on the release film drawn from the release film roll. Here, as a measure for improving the productivity of the ceramic member, it is considered effective to increase the winding length of the release film wound around the release film roll and to reduce the frequency of replacement of the release film roll.

Such a release film roll is fixed or supported by a roll core during storage and transportation. If the winding length is long, bamboo shoot-like slip of the release film wound in a roll shape may occur due to vibration during conveyance or the like. In addition, there is also a possibility that the peeling layer may be damaged due to winding displacement caused by vibration. If the peeling layer is damaged, pinholes may be formed in the dielectric layer. As a measure for avoiding such winding displacement and slipping, it is considered effective to increase the winding strength of the release film.

However, if the winding strength of the release film is increased, the uneven shape of the base film is easily transferred to the release layer. When the winding length is long, the pressure applied to the inner release film increases, and the uneven shape is particularly easily transferred. As a measure for avoiding such a phenomenon, it is considered effective to reduce the winding strength of the release film.

In this way, in order to suppress transfer of the uneven shape near the core, it is sometimes desired to reduce the winding strength, and in order to suppress winding displacement and slippage during transportation, it is sometimes desired to increase the winding strength. In order to increase the winding length of the release film, it is necessary to satisfy such contradictory requirements.

Here, the present disclosure provides a roll of release film that can sufficiently reduce damage generated in a release layer of the release film even if the winding length of the release film is lengthened. In addition, the present disclosure provides a method for manufacturing a ceramic member sheet and a method for manufacturing a ceramic member having excellent reliability by using such a release film roll. In addition, the present disclosure provides a ceramic component sheet and a ceramic component having excellent reliability.

Means for solving the problems

A release film roll of one aspect of the present disclosure has: a release film having a base film and a release layer; and a roll core around which the release film is wound; when the distance r [ mm ] from the outer peripheral surface of the winding core in the radial direction on the side surface is 10-130 mm, the rebound hardness (rebound hardness) K (r) [ HL ] of the peeling film roll at the distance r measured towards the center of the winding core on the surface of the peeling film exposed from the outer peripheral surface of the roll satisfies the following formula (1).

-2r+670≤K(r)≤-1.25r+862.5…(1)

The rebound hardness K (r) varies depending on the amount of air present in the gap between the wound release films. When the amount of air present between the release films is large, the rebound hardness K (r) decreases, and when the amount of air is small, the rebound hardness increases. Here, when the springback hardness K (r) is too high, the adjacent release films are excessively in close contact with each other, and the uneven shape of the base film is easily transferred to the release layer. Since the rebound hardness tends to increase inside the release film roll, therefore, the uneven shape is easily transferred to the inner release film. Here, the peeling film is wound around a portion having a distance r of 10 to 130mm as an inner portion, and the rebound hardness K (r) is set to a specific upper limit value (-1.25r + 862.5) or less. This suppresses transfer of the uneven shape to the release film.

On the other hand, if the rebound hardness K (r) is too low, the air present between adjacent release films increases, and the inner portion of the release film roll tends to slip like a bamboo shoot and tends to be easily displaced by winding due to vibration. In addition, when the peeling film is wound around the outer side, a force applied to the peeling film wound around the inner side may cause the peeling film to be wound in a direction shifted from the winding direction and become too tight, thereby forming wrinkles. Here, in the release film roll, the rebound hardness K (r) is set to a specific lower limit value (-2r + 670) or more at a portion where the distance r is 10 to 130 mm. This suppresses bamboo shoot-like slippage of the release film, winding displacement due to vibration, and winding tension.

Therefore, even if the winding length of the release film is increased in the above-described roll of release film, damage such as unevenness and damage to the release layer of the release film can be sufficiently reduced.

The rebound hardness K (r) in the range of the distance r of less than 10mm is preferably 650HL or more. This can sufficiently suppress occurrence of winding displacement of the release film in the vicinity of the core and separation of the core from the release film roll. In addition, in the portion where the distance r is less than 10mm, the release film roll can be effectively used at the time of replacement work without forming the ceramic green sheet. For example, the present invention can be used as a deceleration zone for decelerating the delivery speed and as a part staying in the drying furnace.

A distance r in the radial direction from the outer peripheral surface of the winding core to the outer peripheral surface of the rolled release film in the release film roll ₀ The hardness K (r) may be 160mm or more and the rebound hardness K (r) at a distance r of 160mm or more may be 350 to 662.5HL. This makes it possible to sufficiently bring adjacent release films into close contact with each other in the entire release film roll, and sufficiently suppress the occurrence of wrinkles in the release film at the outer periphery of the release film roll.

The distance r is in the range of 10 to 130mm, and the release film can be wound so that the rebound hardness K (r) [ HL ] decreases as the distance r increases. This can sufficiently suppress occurrence of winding displacement in both the vicinity of the inner periphery and the vicinity of the outer periphery of the roll of release film.

A method for manufacturing a ceramic member sheet according to one aspect of the present disclosure includes: and a step of forming a ceramic green sheet on the surface of the release layer of the release film drawn from the arbitrary release film roll by using a slurry containing ceramic powder.

The above-mentioned manufacturing method uses a release film drawn from the above-mentioned arbitrary release film roll. The peeling layer of the peeling film is sufficiently prevented from being damaged by winding displacement, sliding phenomenon, and the like, and from being uneven. Therefore, the ceramic green sheet in which the thickness variation and the pinholes are sufficiently reduced can be formed over a wide region from the front end to the rear end of the release film wound around the release film roll. Therefore, a ceramic member sheet having excellent reliability can be produced. In the present disclosure, the "rear end" of the release film refers to the end on the side contacting the winding core, and the "front end" of the release film refers to the end appearing on the outer peripheral surface of the release film roll.

A method of manufacturing a ceramic component according to an aspect of the present disclosure includes: a step of obtaining a laminate including ceramic green sheets by using the ceramic member sheet obtained by the above-described production method; and a step of firing the laminate to obtain a sintered body.

In the above-described manufacturing method, the ceramic member is manufactured using the release film in which the generation of damage due to a winding displacement, a slip phenomenon, or the like, and the unevenness are sufficiently suppressed. Thus, a ceramic green sheet having sufficiently reduced thickness variation and pinholes can be formed. Therefore, a ceramic component having excellent reliability can be produced.

The ceramic member sheet of one aspect of the present disclosure can be obtained by forming a green sheet including a ceramic green sheet on the surface of the release layer of the release film pulled out from the above-described arbitrary release film roll.

The ceramic member sheet can be obtained by using a release film drawn from the above-described arbitrary release film roll. The release layer of the release film sufficiently suppresses generation of damage and irregularities due to winding displacement, sliding phenomenon, and the like. Therefore, the variation in thickness and pinholes of the ceramic green sheet can be sufficiently reduced. The ceramic member sheet obtained by forming a green sheet comprising such a ceramic green sheet has excellent reliability.

A ceramic member according to one aspect of the present disclosure includes a sintered body obtained by forming a laminate of ceramic green sheets including the ceramic member sheet and firing the laminate. The thickness variation and pinholes of the ceramic green sheet are sufficiently reduced. The ceramic component is excellent in reliability because it includes a sintered body obtained by firing a laminate including such ceramic green sheets.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present disclosure, a release film roll in which damage to a release layer of a release film can be sufficiently reduced even if the winding length of the release film is increased can be provided. Further, a method for manufacturing a ceramic member sheet and a method for manufacturing a ceramic member having excellent reliability by using such a release film roll can be provided. In addition, a ceramic member sheet and a ceramic member having excellent reliability can be provided.

Drawings

Fig. 1 is a perspective view of a release film roll according to an embodiment.

FIG. 2 is a sectional view showing an example of a release film.

FIG. 3 is a side view of one embodiment of a roll of release film.

Fig. 4 is a diagram for explaining a method of measuring the rebound hardness K (r).

Fig. 5 is a diagram showing an example of a manufacturing apparatus of a release film roll according to an embodiment.

FIG. 6 is a cross-sectional view of one embodiment of a ceramic component sheet.

FIG. 7 is a cross-sectional view showing a ceramic component according to an embodiment.

FIG. 8 is a graph showing the relationship between the distance r and the spring back hardness K (r) of the release film rolls of examples 1, 2 and 3.

FIG. 9 is a graph showing the relationship between the distance r and the spring back hardness K (r) of the release film rolls of comparative examples 1 and 2.

Fig. 10 is a graph showing the relationship between the distance r and the spring back hardness K (r) of the release film rolls of comparative examples 3 and 4.

Description of the symbols

10. 11 … … winding core; 10a … …;12 … … side; 20 … … peel film; 20a … … peel film; 22 … … substrate film; 23 … …;24 … … a peel-off layer; 24a … … surface; 26. 26a … …;27 … … surface; 30 … …;30b … …;32 … … ceramic green sheet; 32a … … surface; 34 … … electrode blank sheet; 40 … … ceramic part sheet; 50 … … roll (nip roll); 50a … … upper roller; 50b … … lower roller; a 60 … … cut section; 60a … …;60b … … lower knife roll; 70 … … contact roller; 90 … … laminated ceramic capacitor; 92 … … inner layer; 93 … … outer layer portion; 94 … … inner electrode layers; 95 … … terminal electrodes; 96 … … ceramic layer; 100. 200 … … a roll of release film; 102 … …;202 … …;300 … … apparatus.

Detailed Description

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings as appropriate. In the drawings, the same or equivalent elements are denoted by the same reference numerals, and overlapping description will be omitted as appropriate. However, the following embodiments are examples for explaining the present disclosure, and the present disclosure is not intended to be limited to the following.

Fig. 1 is a perspective view of a release film roll according to an embodiment. The release film roll 100 of fig. 1 includes: a release film 20 having a base film and a release layer; and a core 10 around which a release film 20 is wound. The release film 20 is used as a carrier film in a process of manufacturing a ceramic member represented by a laminated ceramic capacitor, for example. In this manufacturing process, for example, a ceramic green sheet to be a dielectric sheet and an electrode green sheet to be an internal electrode are formed on a release film by coating or printing, and then these are peeled and laminated to obtain a laminate, and the laminate is fired to manufacture a ceramic member. The release film 20 is used by being pulled out from the release film roll 100.

The material of the winding core 10 may be paper, plastic, metal, or the like. In the production of ceramic parts, since particles cause pinholes, lightweight plastics containing no paper dust are preferred. Examples of such a material include ABS resin, bakelite (bakelite), and fiber-reinforced plastic. Fiber-reinforced plastics are preferably used because they have not only high mechanical strength but also flexibility. As the fiber-reinforced plastic, a fiber-reinforced plastic obtained by reinforcing a fiber with a thermosetting resin can be cited. Examples of the resin include epoxy resins and unsaturated polyester resins. Examples of the fibers include glass fibers and aromatic polyamide fibers. The resin may be an unsaturated polyester resin, considering cost aspects and the like. From the same point of view, the fibers may be glass fibers.

In the case where the core 10 is made of fiber-reinforced plastic, the spring-back hardness K (r) in the range where r is less than 10mm may be 950HL or less. This can suppress the occurrence of cracking of the core 10. On the other hand, in the case where the winding core 10 is made of metal, the spring-back hardness K (r) in the range of r less than 10mm may exceed 950HL. The outer diameter of the core 10 may be 150mm or less, or 100mm or less. This reduces the size of the release film roll 100, and reduces installation space and transportation cost.

The winding length of the release film 20 wound around the core 10 may be 4000m or more, 5000m or more, or 6000m or more. Thus, in the production process of the ceramic green sheet, the ceramic member, and the like, the frequency of replacement of the release film roll 100 can be reduced, and the production efficiency of various products can be improved. The thickness of the release film 20 may be 10 to 110 μm or 20 to 60 μm. The width of the release film 20 may be, for example, 100 to 1000mm. In the present disclosure, the direction in which the release film is conveyed is referred to as a longitudinal direction, and a direction perpendicular to the longitudinal direction of the release film is referred to as a width direction of the release film, when the release film is pulled out and wound up.

FIG. 2 is a sectional view showing an example of a release film. The release film 20 has a base film 22 and a release layer 24 on one side thereof. The substrate film 22 may be a film of a synthetic resin. Examples of the synthetic resin include polyolefin resins such as polyester resins, polypropylene resins, and polyethylene resins, acrylic resins such as polylactic acid resins, polycarbonate resins, and polymethyl methacrylate resins, polystyrene resins, polyamide resins such as nylon, polyvinyl chloride resins, polyurethane resins, fluorine-based resins (fluorine resins), and polyphenylene sulfide resins. Among them, polyester resins are preferable. Among the polyester resins, polyethylene terephthalate (PET) is more preferable from the viewpoint of mechanical properties, transparency, cost, and the like.

The thickness of the base film 22 is preferably 10 to 100. Mu.m, and more preferably 20 to 50 μm. When the thickness is less than 10 μm, physical properties such as dimensional stability of the release film 20 tend to be impaired. When the thickness exceeds 100 μm, the production cost per unit area of the release film 20 tends to increase.

The base material film 22 may contain a filler (filler) to such an extent that transparency is not impaired, from the viewpoint of sufficiently improving the mechanical strength of the release film 20. In the release film roll 100 of the present embodiment, even if the base film 22 contains a filler, the shape of the filler can be sufficiently suppressed from being transferred to the release layer 24 of the adjacent release film 20. The filler is not particularly limited, and examples thereof include calcium carbonate, calcium phosphate, silica, kaolin, talc, titanium oxide, fumed silica, alumina, and organic particles.

When a polyester film is used as the base film 22, the production can be performed in the following order. First, molten polyester was cast on a rotating cooling drum using an extruder. The molten polyester is extruded through a metal port forming a slit. Then cooled and peeled from the rotating cooling drum, thereby obtaining an unstretched polyester film. By adjusting the gap of the extruder, the thickness of the polyester film and the variation range thereof can be adjusted.

Next, the polyester film that has not been stretched is stretched to adjust the thickness to a desired thickness, and mechanical strength is applied. The stretching of the polyester film is preferably carried out as biaxial stretching. In this case, the transverse extension is performed after the longitudinal extension. The stretching temperature during stretching is preferably not lower than the glass transition temperature and not higher than the melting temperature of the polyester film. When extending longitudinally and transversely, the two pieces can be extended by several times. The variation in thickness of the unstretched film is also inherited after stretching. Therefore, by controlling the thickness variation of the unstretched film, the thickness variation width of the base film 22 and the release film 20 can be adjusted.

The release layer 24 is formed by coating a solution containing a release agent on one surface of the base film 22, drying and curing it. The coating method is not particularly limited, and a reverse coating method, a gravure coating method, a bar coating method, a meyer bar coating method (マイヤーバーコート method), a die coating method, a spray coating method, and the like can be used. The drying may be hot air drying, infrared drying, natural drying, etc. Heating is preferably performed to suppress moisture condensation during drying, and may be about 60 to 120 ℃.

Examples of the release agent used for forming the release layer 24 include silicone release agents, long-chain alkyl release agents, fluorine-containing release agents, and aminoalkyd release agents. The silicone-based release agent group includes an addition reaction type silicone release agent, a condensation reaction type silicone release agent, an ultraviolet curing type release agent, and the like depending on the curing reaction.

The curing conditions may be appropriately selected depending on the curing system of the release agent. For example, when the release agent is an addition-reaction-type silicone, it can be cured by heat treatment at 80 to 130 ℃ for several tens of seconds. In the case of ultraviolet curing, ultraviolet rays may be irradiated to cure the resin using a mercury lamp, a metal halide lamp, or the like as a light source. When radical polymerization is performed by irradiation with ultraviolet rays, curing is preferably performed in a nitrogen atmosphere in order to prevent oxygen inhibition. The range of variation in the thickness of the release layer 24 is preferably small.

The addition reaction type silicone release agent is cured by reacting a substance obtained by introducing a vinyl group into a terminal and/or a side chain of polydimethylsiloxane with hydrogen siloxane. Platinum catalysts may be used in the curing. For example, the curing may be carried out at a curing temperature of about 100 ℃ for several tens of seconds to several minutes. The thickness of the release layer 24 may be about 50 to 300 nm. As the strippers for addition reaction, K847, KS847T, KS-776L, KS-776A, KS-841, KS-774, KS-3703T, KS-3601 (trade names) manufactured by shin Etsu chemical Co., ltd.

The release layer 24 may be formed of a cured product of a (meth) acrylate component and a (meth) acrylate-modified silicone, for example. Since such a cured product can be cured by ultraviolet rays, the thickness of the release layer 24 can be increased. Therefore, for example, when the base material film 22 contains a filler, the surface (release surface) of the release layer 24 can be smoothed by covering the protrusion caused by the filler. In this case, the thickness of the release layer 24 may be 30 to 3000nm.

It is also possible to use a (meth) acrylate monomer and a (meth) acrylate-modified silicone oil which are immiscible with each other. These components are mixed together with the reaction initiator in a solvent, and the mixture is applied to the base material film 22 and then dried. Thus, the silicone-modified silicone oil may be cured with ultraviolet light in a state of being localized near the surface to form the release layer 24. As the (meth) acrylate-modified silicone oil, known ones can be used. For example, X-22-164A, X-22-164B, X-22-174DX and X-22-2445 (trade name) manufactured by shin-Etsu chemical Co., ltd.

The surface of the release layer 24 of the release film 20 is preferably smooth. Specifically, the surface roughness (Rp) of the release layer 24 is preferably 100nm or less, and more preferably 50nm or less. The surface roughness (Rp) of the release layer 24 of the present embodiment is the maximum protrusion height specified in JIS B0601-2001, and can be measured using a contact surface roughness meter or a scanning white interference microscope.

The width of the thickness variation of the release film 20 in the width direction is preferably 0.5 μm or less, more preferably 0.4 μm or less, and still more preferably 0.3 μm or less. Particularly preferably 0.2 μm or less. When the thickness variation width is large, the wound release films 20 strongly contact each other at a thick portion, and the rebound hardness is higher than that at other portions. By reducing the thickness variation width, the deformation of the release film 20 can be suppressed. Further, when the ceramic green sheet is formed on the release film 20, the range of variation in the thickness of the ceramic green sheet can be reduced.

The width of the thickness variation in the width direction of the release film of the present disclosure is the difference between the maximum value and the minimum value of the thickness of the release film between both ends of the release film 20 in the width direction. This is obtained as follows.

The peeling film 20 is provided with a reference point, and a plurality of positions for measuring the thickness of the peeling film are set in the width direction. The interval between the measurement positions may be set as appropriate. For example, since the thickness of the release film is not substantially changed rapidly, the interval of about 1mm to 10mm may be used. The reference point may be, for example, a side edge of the release film. The thickness of the release film was measured at each measurement position, and the film was appropriately moved in the longitudinal direction, thereby measuring the thickness of the release film in time in the same manner. The thickness of the release film is measured at the same position in the width direction, and the thickness of the release film is measured at the same position in the width direction.

Examples of the thickness measuring method include a method using a contact thickness measuring instrument, an optical thickness measuring instrument, a capacitance type thickness measuring instrument, a radiation type thickness measuring instrument using a beta ray, a fluorescent X ray, or the like, and a method of measuring the cross section of the release film 20 by observing it with a microscope. When a contact thickness measuring device is used, the thickness variation of the release film 20 can be directly measured. In addition, the thickness variation widths of the base film 22 and the release layer 24 may be measured by the same method or different methods, and the respective thicknesses may be counted as the thickness of the release film 20. For example, the thickness of the base film 22 may be measured by a radiation type film thickness meter, the thickness of the peeling layer 24 may be measured by an optical type measurement obtained by spectrophotometry, and the respective thickness fluctuation ranges may be counted as the thickness fluctuation range of the peeling film 20. The optical thickness measuring instrument may be set to a diameter of about 0.2 to 2mm as long as the diameter of the measuring point is appropriately set.

Further, a thickness measuring device may be provided in the line of the coating device, the cutting device, or the like, and the thicknesses may be sequentially measured. By performing the thickness measurement with the measurement device set in line in an optical or radiation manner, contact between the measurement device and the release film 20 can be prevented. This can suppress damage and the like and sufficiently maintain the quality of the release film roll. By providing a thickness measuring device in the coating line or the cutting line and measuring the thickness by moving the thickness measuring device back and forth in the width direction during the conveyance of the release film 20, the thickness can be measured over the entire length of the release film 20.

Fig. 3 is a side view of the roll of release film 100. The side surface 12 of the release film roll 100 is exposed at the side end of the release film 20 wound around the core 10. However, in fig. 3, only the outermost release film 20 is shown for the sake of explanation. As shown in FIG. 3, when the distance R [ mm ] measured from the outer peripheral surface 10a of the core 10 of the release film roll 100 in the radial direction R of the release film roll 100 is 10 to 130mm in the side view, the following formula (1) is satisfied.

(-2r+670)≤K(r)≤(-1.25r+862.5)……(1)

In the formula (1), K (r) represents a rebound hardness [ HL ]. The rebound hardness K (r) is determined from the rebound of the ball hitting the surface of the release film 20 on the outer circumferential surface 26 of the release film roll 100. The rebound hardness K (r) can be measured by a Leeb hardness tester or a commercially available tester under the name of a rebound hardness tester. The manufacturing company of the measuring instrument includes SMART SENSOR company. In addition, the rebound hardness in the present disclosure may be referred to as a hardness of richter. In the above formula (1), the upper limit value and the lower limit value of the rebound hardness K (r) are specified when the distance r is 10 to 130 mm.

A distance R in the radial direction R from the outer peripheral surface 10a of the winding core 10 to the outer peripheral surface 26 of the rolled release film 20 ₀ The lower limit of (2) may be 160mm or 200mm. In this case, the distanceWhen r is 160mm or more, the rebound hardness K (r) can be 350 to 662.5HL. This makes it possible to sufficiently bring the adjacent release films 20 into close contact with each other in the entire release film roll 100, and sufficiently suppress the occurrence of wrinkles in the release film on the outer periphery of the release film roll 100. Distance r ₀ The upper limit of (d) may be 500mm.

Fig. 4 is a diagram for explaining a method of measuring the rebound hardness K (r). In the release film roll 100 of fig. 3, the distance r ₀ When the thickness exceeds 130mm, the release film 20 wound around the release film roll 100 is pulled out until the distance r becomes 130mm in order to measure the spring back hardness K (r) with the distance r in the range of 10 to 130 mm. Then, after the distance r from the outer peripheral surface 10a of the winding core 10 to the outer peripheral surface 26A of the roll 23 in the radial direction of the release film roll 100 in the side surface 12A of the roll 23 reaches 130mm, as shown in fig. 4, the sensor of the measuring instrument is pressed against the surface 27 of the release film 20 exposed on the outer peripheral surface 26A of the roll 23 (release film roll), and the rebound hardness K (r) is measured. At this time, the sensor is pressed against the widthwise central portion of the release film 20. Further, as indicated by arrow P, the core is pressed toward the center C of the core. Thus, the rebound hardness K (r) was measured at a distance r of 130 mm. Then, while the release film 20 is pulled out, the rebound hardness K (r) of the distance r in the range of 10 to 130mm may be measured. In general, since the rebound hardness of a roll of release film does not change drastically, the rebound hardness K (r) can be measured at a distance r of about 5mm. In addition, at a distance r ₀ When the distance r exceeds 130mm, in the process of pulling out the release film 20 wound around the release film roll 100 until the distance r reaches 130mm in order to measure the spring back hardness K (r) with the distance r in the range of 10 to 130mm, the distance r is appropriately set in the same manner as described above, and the distance r from 130mm to 130mm is measured ₀ The rebound hardness K (r) of (1) is also convenient.

When the distance r is 10 to 130mm, if the springback hardness K (r) becomes high, the adjacent release films 20 are excessively adhered to each other, and the uneven shape of the base film 22 is easily transferred to the release layer 24. When the ceramic green sheet is formed on the release film 20, the range of variation in the thickness of the ceramic green sheet tends to be large. On the other hand, when the springback hardness K (r) is low, the air existing between the adjacent release films 20 increases, and the release film 20 tends to easily slide in a bamboo shoot shape and tends to easily generate a winding displacement due to vibration in the inner portion of the release film roll 100. If this phenomenon occurs, the peeling layer 24 is damaged, and pinholes tend to occur in the ceramic green sheet formed on the peeling film. Since the release film roll 100 of the present embodiment satisfies the above formula (1), damage (unevenness and damage) to the release layer 24 of the release film 20 can be sufficiently reduced.

The distance r is in the range of 10 to 130mm, and the release film 20 may be wound so that the rebound hardness K (r) decreases as the distance r increases. This can sufficiently suppress occurrence of winding displacement in both the inner circumferential portion and the outer circumferential portion of the release film roll 100. When the distance r is 130mm or more, the release film 20 may be wound so that the rebound hardness K (r) decreases as the distance r increases. In the range where the distance r is less than 10mm, the rebound hardness K (r) may be 650HL or more. This can sufficiently suppress the occurrence of winding displacement of the release film near the core 10 and the detachment of the core 10 from the release film roll 100. In addition, the portion where the distance r is less than 10mm can be effectively used in the replacement work of the peeling film roll without forming the ceramic green sheet.

Fig. 5 is a diagram showing an example of a manufacturing apparatus for the release film roll 100. In the manufacturing apparatus 300 of fig. 5, the release film roll 200 is used. The release film roll 200 winds the release film 20A having a width (for example, 1 to 2 m) wider than that of the release film 20 around the core 11. The release film roll 200 is manufactured by winding the release film 20A around the core 11 by a known method. In this case, the release film 20A may be wound around the core 11 with the base film side as the inside, or may be wound with the release film side as the inside.

The manufacturing apparatus 300 inserts the winding core 11 of the release film roll 200 into the rotating shaft 202 on the upstream side, and the rotating shaft 202 rotatably supports the release film roll 200. The manufacturing apparatus 300 further includes: a nip roller 50 including a pair of rollers that vertically sandwich the release film 20A drawn out from the release film roll 200; a cutting unit (60); and a winding core 10 inserted into the release film roll 100 and rotatably supporting a winding shaft 102 of the winding core 10.

In the roll 50, the upper roll 50a may be a roll whose surface is made of rubber. The lower roller 50b may be a roller whose surface is made of metal. The roll 50 has a function of making the tension of the release film 20A different between the upstream side and the downstream side thereof. This allows highly free tension control when the release film 20 is wound around the core 10.

The cutting section 60 includes an upper blade roller 60a and a lower blade roller 60b. The upper blade roller 60a may mount a plurality of upper blades at certain intervals in the direction of its rotational axis. The upper blade of the upper blade roll 60a may engage with the lower blade roll 60b. The release film 20A passing through the nip roller 50 is cut in the longitudinal direction between the upper blade roller 60A and the lower blade roller 60b. Thereby, the film is divided into, for example, release films 20 having a width of 100 to 500mm. When a plurality of winding cores 10 are attached to the winding shaft 102 and the cut release film 20 is wound around the winding cores 10 while being pressed by the touch roller 70, a plurality of release film rolls 100 can be manufactured at one time. A known slitter (slitter) such as a gang knife (gang blades) may be used as the cutting unit 60. The cutting portion 60 may not be provided. In this case, one release film roll 100 can be obtained from one release film roll 200.

The release film 20 cut by the cutting unit 60 is wound around a winding core 10 attached to a winding shaft 102. At this time, the winding shaft 102 rotates at a specific torque, and the contact roller 70, which rotates while contacting the release layer 24 of the release film 20, presses the wound release film 20 against the core 10. That is, the release film 20 is wound while being pressed by the contact roller 70. The contact roller 70 may also be rotationally driven. In this manner, by using the contact roller 70, air between the release films 20 can be sufficiently reduced without increasing the tension. This can suppress occurrence of winding displacement, a slip phenomenon, and winding tension, and prevent the release layer 24 from being wrinkled or damaged.

The rebound hardness K (r) on the surface of the release layer 24 of the release film 20 wound around the release film roll 100 can be adjusted by controlling the pressing force and driving force of the contact roller 70 and controlling the torque of the winding shaft 102. For example, if the release film 20 is cut and wound, the diameter (roll diameter) of the release film roll 100 gradually increases. The winding tension is adjusted to a desired tension by controlling the torque of the winding shaft 102 in accordance with the winding diameter at the time of winding. When the tension is reduced more than necessary as the winding diameter increases and the rebound hardness K (r) is less than the lower limit, the rebound hardness can be increased by increasing the torque of the winding shaft 102. Further, even if the winding diameter is large, the tension is not sufficiently reduced, and when the springback hardness K (r) exceeds the upper limit, the torque of the winding shaft 102 can be reduced, and the springback hardness can be reduced.

The method of manufacturing the release film roll 100 is not limited to the above method. For example, the contact roller may be driven to adjust the torque of the contact roller.

Fig. 6 is a sectional view of a ceramic member sheet according to an embodiment of the present disclosure. The method for manufacturing the ceramic member sheet 40 of fig. 6 includes the steps of: a green sheet 30 including a ceramic green sheet 32 and an electrode green sheet 34 is formed on a surface 24a of a release layer 24 of a release film 20 drawn from a release film roll 100, using a slurry including ceramic powder and an electrode slurry.

The ceramic green sheet 32 may be formed by coating a ceramic slurry containing ceramic powder and drying it. The electrode green sheet 34 may be formed by coating an electrode slurry on the ceramic green sheet 32 and drying it.

The ceramic slurry can be prepared by kneading a dielectric material (ceramic powder) with an organic medium, for example, in the case of a laminated ceramic capacitor. As the dielectric material, various compounds which become a composite oxide or an oxide by firing can be cited. For example, a carbonate, a nitrate, a hydroxide, an organic metal compound, or the like can be appropriately selected and used. The dielectric material has an average particle diameter of 4 μm or less, preferably 0.1 to 3.0 μm.

The electrode paste can be prepared by, for example, kneading at least one selected from a conductive material such as various conductive metals and alloys, and a material which becomes a conductive material after firing such as various oxides, organic metal compounds, and resinates, with an organic vehicle. As the conductive material used in the production of the electrode paste, ni metal, ni alloy, or a mixture of these is preferably used. The electrode paste may also include a plasticizer to improve adhesion. Examples of the plasticizer include phthalic acid esters such as Butyl Benzyl Phthalate (BBP), adipic acid, phosphoric acid esters, and glycols.

The organic vehicle included in the ceramic slurry and the electrode slurry may be prepared by dissolving a binder resin in an organic solvent. Examples of the binder resin used for the organic medium include ethyl cellulose, acrylic resins, butyral resins, polyvinyl acetal, polyvinyl alcohol, polyolefins, polyurethanes, polystyrene, and copolymers thereof. Among them, butyral resins, specifically polyethylene butyral resins are preferably used. The mechanical strength of the ceramic green sheet can be improved by using the butyral resin. One or both of the ceramic slurry and the electrode slurry may contain at least one additive selected from various dispersants, plasticizers, antistatic agents, dielectrics, glass frits, insulators, and the like, as necessary.

The ceramic slurry is applied to the surface 24a of the release layer 24 of the release film 20 using, for example, a squeegee device. Then, the applied ceramic slurry is dried in a drying apparatus at a temperature of, for example, 50 to 100 ℃ for 1 to 20 minutes to form a ceramic green sheet 32. The ceramic green sheet 32 shrinks by 5 to 25% compared to before drying.

Then, the electrode paste is printed on the surface 32a of the ceramic green sheet 32 so as to form a specific pattern, for example, using a screen printing apparatus. The printed electrode paste is dried in a drying apparatus at a temperature of, for example, 50 to 100 ℃ for 1 to 20 minutes to form an electrode green sheet 34. In this manner, the ceramic member sheet 40 in which the ceramic green sheet 32 and the electrode green sheet 34 are sequentially laminated on the peeling layer 24 of the peeling film 20 can be obtained.

When the irregularities of the release film 20 in the release film roll 100 are large, the range of thickness variation of the ceramic green sheet 32 is large. The release film 20 drawn from the release film roll 100 has sufficiently reduced generation of damage and irregularities due to winding displacement, sliding phenomenon, and the like in the release layer 24. Therefore, the ceramic green sheet 32 in which the thickness variation is sufficiently suppressed can be formed over a wide region from the front end to the rear end of the release film 20 wound around the release film roll 100. The ceramic member manufactured by using the ceramic member sheet 40 including the ceramic green sheet has excellent reliability.

The thicknesses of the ceramic green sheet 32 and the electrode green sheet 34 may be 1.0 μm or less, respectively. Even if the thickness is so small, variation in thickness is suppressed, and thus a ceramic component having high reliability can be obtained. The ceramic member sheet of the present disclosure is not limited to the sheet of fig. 6, and may be constituted of only the ceramic green sheet 32 without the electrode green sheet, for example.

A method for manufacturing a ceramic component according to an embodiment of the present disclosure includes: a laminating step of preparing a plurality of ceramic member sheets and laminating green sheets of the plurality of ceramic member sheets to obtain a laminate; a firing step of firing the laminate to obtain a sintered body; and an electrode forming step of forming a terminal electrode on the sintered body to obtain a multilayer ceramic capacitor.

FIG. 7 is a sectional view showing an example of a multilayer ceramic capacitor manufactured by the above-described manufacturing method. The multilayer ceramic capacitor 90 includes an inner layer 92 and a pair of outer layers 93 sandwiching the inner layer 92 in the stacking direction. The multilayer ceramic capacitor 90 has a terminal electrode 95 on a side surface.

The inner portion 92 includes a plurality of (13 in this example) ceramic layers 96 (dielectric layers) and a plurality of (12 in this example) internal electrode layers 94. The ceramic layers 96 are alternately laminated with the internal electrode layers 94. The internal electrode layer 94 is electrically connected to the terminal electrode 95. The outer layer portion 93 is formed of a ceramic layer. The ceramic layer may be formed in the same manner as the ceramic green sheet 32, for example.

In the laminating step, the release film 20 of the ceramic member sheet 40 shown in fig. 6 is peeled off to obtain a green sheet 30. One surface 30b of the green sheet 30 is laminated on the outer layer green sheet. The other release film 20 is peeled from the other ceramic member sheet 40 to obtain the other green sheet 30, and the electrode green sheet 34 of the green sheet peeled first is laminated so as to face the other green sheet 30b of the other green sheet 30. Thereafter, by repeating such a sequence, the green sheets 30 are laminated, thereby obtaining a laminated body. That is, in this lamination step, the release film 20 is peeled off to obtain the green sheet 30, and the green sheets 30 are sequentially laminated. By repeating this sequence a plurality of times, a stacked body is formed. Finally, lamination of the outer layer green sheets was also performed.

The number of laminated sheets of the green sheet of the laminate is not particularly limited, and may be, for example, several tens to several hundreds of layers. A slightly thick outer layer green sheet on which no electrode layer is formed may be provided on both end surfaces perpendicular to the lamination direction of the laminate. After the laminate is formed, the laminate may be cut to obtain a green sheet.

In the firing step, a laminating stepThe laminate (green sheet) obtained in (a) was fired to obtain a sintered body. The firing conditions are preferably performed at 1100 to 1300 ℃ under an atmosphere of a humidified mixed gas of nitrogen and hydrogen, or the like. However, the oxygen partial pressure in the atmosphere at the time of firing is preferably 10 ^-2 Pa or less, more preferably 10 ^-2 ～10 ^-8 Pa. Further, the binder removal treatment of the laminate is preferably performed before firing. The binder removal treatment may be carried out under ordinary conditions. For example, when using a base metal such as Ni or a Ni alloy as a conductor material of the internal electrode layers, it is preferable to perform the process at 200 to 600 ℃.

After firing, heat treatment may be performed to reoxidize the ceramic layers constituting the sintered body. The holding temperature or maximum temperature of the heat treatment is preferably 1000 to 1100 ℃. The oxygen partial pressure at the time of heat treatment is preferably higher than that of the reducing atmosphere at the time of firing, and more preferably 10 ^-2 Pa to 1Pa. The sintered body thus obtained is preferably subjected to end surface polishing by barrel polishing, sandblasting or the like, for example.

In the electrode forming step, the terminal electrode 95 is formed by firing the terminal electrode paste on the side surface of the sintered body, whereby the multilayer ceramic capacitor 90 shown in fig. 7 can be obtained. In the method of manufacturing the multilayer ceramic capacitor 90, the release film roll 100 having the release layer that sufficiently reduces damage due to unevenness of the release film 20, winding displacement, and the like is used. Therefore, the thickness unevenness and pinholes in the ceramic layers 96 and the internal electrode layers 94 can be sufficiently reduced. Therefore, the withstand voltage is suppressed from decreasing, and the reliability is excellent.

While several embodiments have been described above, the present disclosure is not limited to the above embodiments. For example, although a multilayer ceramic capacitor has been described as an example of the ceramic member, the ceramic member of the present disclosure is not limited to the multilayer ceramic capacitor, and may be another ceramic member, for example. The ceramic component may also be, for example, a varistor or a laminated inductor.

Examples

The present disclosure will be described in more detail with reference to examples and comparative examples, but the present disclosure is not limited to the following examples.

(example 1)

< production of Release film roll >

To make a release film, a release agent solution was prepared according to the following procedure. 0.25 part by mass of an acrylate-modified silicone oil (trade name: X-22-2445, manufactured by shin-Etsu chemical Co., ltd.), 100 parts by mass of methyl ethyl ketone, and 100 parts by mass of toluene were prepared with respect to 100 parts by mass of nonanediol diacrylate. These were put into a metal container and mixed with stirring to obtain a colorless transparent solution.

To the solution was added 2.5 parts by mass of a reaction initiator (trade name: omnirad127, manufactured by IGM ratios B.V.) to prepare a coating solution. The coating liquid was extruded from the slit of the coating apparatus, coated on one surface of a biaxially stretched polyethylene terephthalate film (PET film, thickness: 30 μm) having a width of 1100mm, and blown with hot air at a temperature of 80 ℃ for 30 seconds to evaporate methyl ethyl ketone and toluene. Thereby, a coating layer was formed on the PET film.

Subsequently, the coated layer was cured by irradiation with ultraviolet light in a nitrogen atmosphere having an oxygen concentration of 100ppm, thereby forming a release layer having a release function. Thus, a release film (before cutting) having a release layer on one surface of the PET film was obtained. The surface roughness (Rp) of the release layer of the release film was measured using a scanning type white interference microscope (device name: VS1540, manufactured by Hitachi High-Tech Science Corporation). As a result, the surface roughness (Rp) of the release layer was 30nm. The release film was wound around a core to obtain a release film roll (before cutting). The thickness of the release layer was 1 μm, and the width of thickness variation, which is the difference between the maximum value and the minimum value of the thickness of the release film in the width direction, was 0.5 μm. The total length of the release film thus produced was 7000m.

The roll of release film (before cutting) was mounted on a rotating shaft 202 using a manufacturing apparatus shown in fig. 5. The release film drawn from the release film roll (before cutting) was cut into 5 pieces by a cutting unit 60 along the longitudinal direction, and the pieces were set to have a width of 200mm. As shown in fig. 5, each of 5 release films (after cutting) was wound around the core 10 so that the release layer 24 was positioned outside. At the time of winding, the contact roller 70 is pressed against the release film roll 100, and the winding shaft 102 and the contact roller 70 are rotated and driven to wind the release film rollWound around the winding core 10. Thus, 5 rolls of release film were obtained. The 5 rolls of release film were wound under the same conditions. The winding lengths of the 5 rolls of release film were 6000m. In addition, in 5 peeling film rolls, the distance r from the outer peripheral surface of the roll core to the outer peripheral surface of the peeling film wound in a roll shape ₀ Are all about 205mm.

< measurement of rebound hardness K (r) >

The rebound hardness K (r) of the release layer of the 1 st release film roll out of the 5 release film rolls thus obtained was measured. A numerical hardness meter (trade name: AR936, measurement range: 170 to 960 HLD) manufactured by SMART SENSOR was used for the measurement of the rebound hardness K (r).

The measurement of the spring back hardness K (r) was performed by pressing a sensor of a digital hardness meter against the center C of the core on the surface (central portion in the width direction) of the release layer of the release film wound around the outermost release film in the release film roll. The measurement was carried out by measuring the rebound hardness K (r) of the release film roll when the distance r in the radial direction reached a predetermined value while unwinding the release film roll. Specifically, the measurement was carried out at intervals of 10mm in a range of r from 195mm to 135 mm. That is, the rebound hardness K (r) was measured at distances r of 195mm, 185mm and … … mm, respectively. The distance r is measured at intervals of 5mm in the range of 135mm to 5mm. That is, the rebound hardness K (r) was measured at distances r of 135mm, 130mm and … … m, respectively. FIG. 8 is a graph showing the relationship between the distance r and the rebound hardness K (r) in example 1. As shown in FIG. 8, the rebound hardness K (r) satisfies the above formula (1) when the distance r is 10 to 130 m.

< formation and evaluation of dielectric Green sheet >

The release film was pulled out from the 2 nd roll of the 5 rolls of release film, and the surface state of the release layer of the release film was visually inspected. As a result, no particular abnormality was observed. Using the 3 rd release film roll of the 5 release film rolls, a dielectric green sheet was formed as a ceramic member sheet according to the following procedure. BaTiO powders were prepared as ceramic powders, respectively ₃ Is a powder, polyvinyl butyral (PVB) as an organic binder, and methanol as a solvent. Next, 10 parts by mass of an organic binder and 165 parts by mass of a binder were mixed with 100 parts by mass of the ceramic powderThe solvent was kneaded in the amount of parts by ball mill to obtain a dielectric slurry.

The release film roll is attached to a coater, and a dielectric slurry is applied to the release film side of the release film drawn out from the release film roll to form a dielectric green sheet on the release film. The thickness of the dielectric green sheet was set to 0.9. Mu.m. The presence or absence of pinholes in the dielectric green sheet formed on the release film and the range of thickness variation of the dielectric green sheet were examined. The presence or absence of the pin hole was investigated by an image processing inspection apparatus. The thickness variation width was continuously measured using a transmission type X-ray film thickness meter (trade name: accureX, manufactured by FUTEC INC.) disposed on one line. The thickness variation width is obtained from the average value, the maximum value and the minimum value of the thickness. That is, the larger of the absolute value of the maximum value-average value and the absolute value of the minimum value-average value is taken as the thickness variation width.

As a result, the average thickness of the dielectric green sheets was 0.9 μm, and the range of thickness variation was 0.04 μm. The range of variation was within. + -. 5% (0.045 μm) of the set thickness (0.9 μm), and the product was found to be good. In addition, no pinholes were detected.

(example 2)

A release film roll was produced in the same manner as in example 1, except that the torque of the take-up shaft 102 when the release film was taken up (after cutting) by the take-up device was adjusted so that the tension applied to the taken-up release film was about 0.8 times that of example 1. Then, measurement of the spring back hardness K (r), formation of a dielectric green sheet, and evaluation were performed in the same manner as in example 1. FIG. 8 is a graph showing the relationship between the distance r and the rebound hardness K (r) in example 2. As shown in FIG. 8, the rebound hardness K (r) satisfies the above formula (1) when the distance r is 10 to 130 m. The release film was pulled out from the release film roll, and the surface state of the release layer of the release film was visually inspected. As a result, no particular abnormality was observed. The average thickness of the dielectric green sheets was 0.9. Mu.m. The range of variation in the thickness of the dielectric green sheet was 0.03 μm, and the dielectric green sheet was good. In addition, no pinholes were detected.

(example 3)

A release film roll was produced in the same manner as in example 1, except that the torque of the take-up shaft 102 when the release film was taken up (after cutting) by the take-up device was adjusted so that the tension applied to the taken-up release film was about 0.6 times that of example 1. Then, measurement of the spring back hardness K (r), formation of a dielectric green sheet, and evaluation were performed in the same manner as in example 1. FIG. 8 is a graph showing the relationship between the distance r and the rebound hardness K (r) in example 3. As shown in FIG. 8, the rebound hardness K (r) satisfies the above formula (1) when the distance r is 10 to 130 m. Further, the release film was pulled out from the release film roll, and the surface state of the release layer of the release film was visually inspected. As a result, no particular abnormality was observed. The average thickness of the dielectric green sheet was 0.9 μm. The range of variation in the thickness of the dielectric green sheet was 0.03 μm, and the dielectric green sheet was good. In addition, no pinholes were detected.

Comparative example 1

A release film roll was produced in the same manner as in example 1, except that the torque of the take-up shaft 102 when the release film was taken up (after cutting) by the take-up device was adjusted and the tension applied to the taken-up release film was set to about 1.3 times that of example 1. Then, measurement of the spring back hardness K (r), formation of a dielectric green sheet, and evaluation were performed in the same manner as in example 1. FIG. 9 is a graph showing the relationship between the distance r and the rebound hardness K (r) in comparative example 1. As shown in FIG. 9, when the distance r is 10 to about 45mm, the rebound hardness K (r) exceeds the upper limit of the above formula (1). The release film was pulled out from the release film roll, and the surface state of the release layer of the release film was visually inspected. As a result, no particular abnormality was observed. On the other hand, the range of variation in the thickness of the dielectric green sheet increases as the distance from the winding core increases. The variation in thickness of the dielectric green sheet on the release film between 40mm from the rear end of the release film was out of 0.06. Mu.m, and could not satisfy within. + -. 5% of the set thickness (0.9. Mu.m).

Comparative example 2

A release film roll was produced in the same manner as in example 1, except that the torque of the take-up shaft 102 when the release film was taken up (after cutting) by the take-up device was adjusted and the tension was set to about 0.3 times that of example 1. The rebound hardness K (r) was measured in the same manner as in example 1. FIG. 9 is a graph showing the relationship between the distance r and the rebound hardness K (r) in comparative example 2. As shown in FIG. 9, when the distance r is about 30 to about 115mm, the rebound hardness K (r) is lower than the lower limit of the above formula (1). When the dielectric green sheet is formed, the release film in the vicinity of the core of the release film roll bulges in a bamboo shoot shape when the sheet is conveyed, and the roll shape becomes uneven. At this point, the release film roll of comparative example 2 was judged to be unsuitable, and the evaluation was terminated.

Comparative example 3

At the time of winding, the torque of the winding shaft 102 was prepared so that the tension applied to the wound release film was substantially constant, and the pressure of the contact roller against the release film roll was set to about 1.5 times that of example 1. Except for this, a release film roll was produced in the same manner as in example 1. The rebound hardness K (r) was measured in the same manner as in example 1. FIG. 10 is a graph showing the relationship between the distance r and the rebound hardness K (r) in comparative example 3. As shown in FIG. 10, when the distance r is about 110 to 130mm, the rebound hardness K (r) exceeds the upper limit of the above formula (1).

The release film was pulled out from the release film roll, and the surface state of the release layer of the release film was visually inspected. As a result, a plurality of wrinkles extending in the longitudinal direction of the release film were formed in the width direction in the core-side portion where the distance r was 70mm or less, and it was confirmed that the release film was deformed. It is considered that the deformation due to such wrinkles is affected by the winding tension. At this point, the release film roll of comparative example 3 was judged to be unsuitable, and the evaluation was terminated.

Comparative example 4

The winding torque is not greatly changed from the start of winding to the end of winding. The pressure of the touch roller against the release film roll was set to about 0.7 times that of example 1. Further, a release film roll was produced in the same manner as in example 1. The rebound hardness K (r) was measured in the same manner as in example 1. Fig. 10 is a graph showing the relationship between the distance r and the rebound hardness K (r) in comparative example 4. As shown in FIG. 10, when the distance r is about 35 to 130mm, the rebound hardness K (r) is lower than the lower limit of the above formula (1).

The side end portions (cut portions) of the release film at the outer periphery of the obtained release film roll are irregular. The release film was pulled out from the release film roll, and the surface state of the release layer of the release film was visually inspected. As a result, in a region within about 3cm from the side end portion toward the inside, deformation such as bending of the release film was observed. As a result of the side end portion being irregular, pressure deformation acts in the vicinity of the side end portion, and as a result, the peeling film is considered to be deformed. At this point, the release film roll of comparative example 4 was judged to be unsuitable, and the evaluation was ended.

[ industrial applicability ]

According to the present disclosure, a release film roll in which damage to a release layer of a release film can be sufficiently reduced even if the winding length of the release film is increased can be provided. Further, a method for producing a ceramic member sheet and a method for producing a ceramic member having excellent reliability by using such a release film roll can be provided. In addition, a ceramic member sheet and a ceramic member having excellent reliability can be provided.

Claims

1. A roll of release film, wherein,

the release film roll has: a release film having a base film and a release layer, and a core around which the release film is wound;

in the side surface, when the distance r from the outer peripheral surface of the winding core in the radial direction is 10-130 mm, the rebound hardness K (r) of the peeling film roll at the distance r measured towards the center of the winding core on the surface of the peeling film exposed at the outer peripheral surface of the roll satisfies the following formula (1),

-2r+670≤K(r)≤-1.25r+862.5……(1)，

the unit of r is mm and the unit of K (r) is HL.

2. The roll of release film of claim 1,

and when the distance r is less than 10mm, the rebound hardness K (r) is more than 650 HL.

3. The release film roll according to claim 1 or 2,

a distance r from the outer peripheral surface of the winding core to the outer peripheral surface of the rolled release film in the radial direction ₀ 160mm or more, and when the distance r is 160mm or more, the rebound hardness K (r) is 350 to 662.5HL.

4. The release film roll according to any one of claims 1 to 3,

in the range of 10 to 130mm, the rebound hardness K (r) decreases as the distance r increases, wherein the unit of K (r) is HL.

5. A method for producing a ceramic member sheet, wherein,

comprising: a step of forming a ceramic green sheet on the surface of the release layer of the release film pulled out from the release film roll according to any one of claims 1 to 4 using a slurry containing ceramic powder,

the thickness of the ceramic green sheet is 1.0 [ mu ] m or less.

6. A method for manufacturing a ceramic component, wherein,

comprising:

a step of obtaining a laminate including the ceramic green sheet by using the ceramic member sheet obtained by the manufacturing method according to claim 5; and

and a step of firing the laminate to obtain a sintered body.

7. A sheet for a ceramic part, wherein,

the ceramic member sheet is obtained by forming a green sheet including a ceramic green sheet on the surface of the release layer of the release film drawn from the release film roll of any one of claims 1 to 4.

8. A ceramic part, wherein,

comprises a sintered body and a sintered body formed by sintering,

the sintered body is obtained by forming a laminate of ceramic green sheets comprising the ceramic member sheet according to claim 7 and firing the laminate.