Laminated film

Abstract

A laminated film 10 is provided with a base film 11 and a rubber layer 12 that is laminated on the base film 11 and contains an elastomer as a main component. The amount of deformation in the thickness direction as measured by the compression test A mentioned below is 14.5 μm or more.　<Compression Test A> A pressure of 5 MPa is applied in the thickness direction from the rubber layer 12 side of the laminated film 10 under the conditions of a temperature of 25°C and a compression speed of 50 g / min by using a cylindrical compression probe having a diameter of 1 mm.

Description

Laminated Film

[0001] The present invention relates to a laminated film.

[0002] Multilayer ceramic capacitors (MLCCs) have been widely used as one of the main electronic components in electronic devices. Multilayer ceramic capacitors are manufactured by press-molding a laminate of multiple ceramic green sheets, each having an internal electrode pattern formed thereon, cutting the laminate into chips of a predetermined size, and then firing the laminate. To prevent direct contact between the press plate and the laminate during press-molding, a buffer material is placed between the press plate and the laminate. A sheet or film made of polyethylene terephthalate (PET) is typically used as the buffer material (see, for example, Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2016-207965

[0004] In recent years, in order to realize a higher capacitance of multilayer ceramic capacitors in response to the increasing performance of electronic devices, ceramic green sheets have been made thinner and the number of layers has been increased. However, the reduction in thickness of ceramic green sheets and the increase in the number of layers tend to increase the step between the surface of the ceramic green sheets and the irregularities of the internal electrode patterns. Conventional cushioning materials have room for improvement in terms of their ability to conform to the step.

[0005] Therefore, an object of the present invention is to provide a laminated film that has excellent conformability to unevenness.

[0006] The present invention provides a laminated film comprising: a substrate film; and a rubber layer containing an elastomer as a main component laminated on the substrate film, wherein the amount of deformation in the thickness direction measured by the following compression test A is 14.5 μm or more. <Compression test A> A pressure of 5 MPa is applied in the thickness direction from the rubber layer side of the laminated film using a cylindrical compression probe with a diameter of 1 mm at a temperature of 25°C and a compression rate of 50 g / min.

[0007] According to the present invention, it is possible to provide a laminated film that has excellent conformability to unevenness.

[0008] FIG. 1 is a cross-sectional view schematically showing an example of a laminate film of the present invention. FIG. 2 is a cross-sectional view schematically showing an example of press molding in a method for producing a multilayer ceramic capacitor. FIG. 3 is a cross-sectional view schematically showing an example of a film member of the present invention. FIG. 4 is a schematic view illustrating a compression test A. FIG. 5 is a schematic view illustrating a tensile test. FIG. 6 is a schematic view illustrating a pressure test. FIG. 7 is a schematic view illustrating a compression test B. FIG. 8 is a pressure-sensitive paper image (a) after a pressure test of the laminate film of Example 1, and a binarized image (b) showing a circle with a radius of 5 mm from a point corresponding to the center of the plate-like member in the binarized image obtained by binarizing the image (a). FIG. 9 is a pressure-sensitive paper image (a) after a pressure test of the laminate film of Example 5, and a binarized image (b) showing a circle with a radius of 5 mm from a point corresponding to the center of the plate-like member in the binarized image obtained by binarizing the image (a). Fig. 10 is an image (a) of pressure-sensitive paper after a pressure test of the film of Comparative Example 1, and a diagram (b) showing a circle with a radius of 5 mm from a point corresponding to the center of the plate-like member in the binarized image obtained by binarizing the image (a). Fig. 11 is an image (a) of pressure-sensitive paper after a pressure test of the film of Comparative Example 3, and a diagram (b) showing a circle with a radius of 5 mm from a point corresponding to the center of the plate-like member in the binarized image obtained by binarizing the image (a).

[0009] A laminated film according to a first aspect of the present invention comprises a substrate film and a rubber layer laminated on the substrate film and containing an elastomer as a main component, and exhibits a deformation in the thickness direction of 14.5 μm or more as measured by the following compression test A. <Compression test A> A pressure of 5 MPa is applied in the thickness direction from the rubber layer side of the laminated film using a cylindrical compression probe with a diameter of 1 mm at a temperature of 25° C. and a compression rate of 50 g / min.

[0010] In a second aspect of the present invention, for example, in the laminated film according to the first aspect, the elastomer includes silicone rubber.

[0011] In a third aspect of the present invention, for example, in the laminate film according to the first or second aspect, the base film contains a polyester resin as a main component.

[0012] In a fourth aspect of the present invention, for example, in the laminate film according to the third aspect, the polyester resin contains polyethylene terephthalate.

[0013] In a fifth aspect of the present invention, for example, in the laminate film according to any one of the first to fourth aspects, the ratio of the thickness of the rubber layer to the thickness of the base film is 0.35 or more and 3.5 or less.

[0014] In a sixth aspect of the present invention, for example, in the laminate film according to any one of the first to fifth aspects, the tensile modulus of a test piece measured by the following tensile test is 6.5 MPa or more and 30 MPa or less. <Tensile Test> The rubber layer is punched out with a No. 3 dumbbell-shaped test piece punching blade to obtain a test piece. In accordance with JIS K7127:1999, a tensile test of the test piece is carried out using a tensile tester under conditions of 25°C and 50% RH at a tensile speed of 200 mm / min.

[0015] In a seventh aspect of the present invention, for example, in the laminate film according to any one of the first to sixth aspects, a pressure-sensitive paper that changes color when subjected to pressure and a 20 mm square stainless steel plate-like member having a first main surface with a 1 mm wide, 0.010 mm deep groove formed thereon and a flat second main surface are used. When the pressure-sensitive paper is then binarized, the ratio of the area of ​​dark areas to the area of ​​a circle with a radius of 5 mm from the point corresponding to the center of the plate-like member in the binarized image is 95% or more. <Pressure Test> The pressure-sensitive paper, the laminate film, and the plate-like member are laminated in this order between a lower pressure plate and an upper pressure plate, with the rubber layer of the laminate film facing the first main surface of the plate-like member. A pressure of 95 MPa is applied in the thickness direction from the upper pressure plate at a temperature of 25°C and maintained for 1 minute.

[0016] In an eighth aspect of the present invention, for example, in a laminate film according to any one of the first to seventh aspects, when the deformation in the thickness direction measured in the compression test A is defined as λ1 and the deformation in the thickness direction measured in the compression test A after five cycles of the following compression test B is defined as λ2, the rate of change expressed as (λ1 - λ2) / λ1 x 100 is 25% or less. <Compression Test B> The laminate film and a 2 mm thick, 50 mm square stainless steel plate-like member are laminated in this order from bottom to top between a lower pressure plate and an upper pressure plate. The rubber layer of the laminate film and the plate-like member are arranged facing each other. A pressure of 60 MPa is applied in the thickness direction from the upper pressure plate at a temperature of 90°C and maintained for 10 minutes.

[0017] In a ninth aspect of the present invention, for example, the laminate film according to any one of the first to eighth aspects is used as a cushioning material, a release material, a sealing material, a protective material, or a filler.

[0018] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the accompanying drawings, but is not limited to the following embodiments.

[0019] [Laminate Film] An example of the laminate film of the present invention is shown in Figure 1. The laminate film 10 shown in Figure 1 includes a base film 11 and a rubber layer 12 laminated on the base film 11. The rubber layer 12 contains an elastomer as a main component. In this specification, "main component" refers to the component that is contained in the largest amount by weight. In the example shown in Figure 1, the laminate film 10 has a first main surface 101 on the base film 11 side and a second main surface 102 on the rubber layer 12 side. In this specification, the "main surface" refers to the surface of the film-like member that has the largest area. In the laminate film 10, the deformation amount in the thickness direction of the laminate film 10 measured by the following compression test A is 14.5 µm or more.

[0020] <Compression Test A> A pressure of 5 MPa is applied in the thickness direction from the rubber layer 12 side of the laminated film 10 using a cylindrical compression probe with a diameter of 1 mm at a temperature of 25° C. and a compression rate of 50 g / min.

[0021] The laminated film 10 is used, for example, as a buffer material during press molding in a method for manufacturing a multilayer ceramic capacitor. A uniaxial press or a hydrostatic press is generally used for press molding. FIG. 2 is a schematic cross-sectional view illustrating an example of press molding in a method for manufacturing a multilayer ceramic capacitor. FIG. 2 illustrates press molding using a uniaxial press. The method for manufacturing a multilayer ceramic capacitor includes, for example, a step of forming an internal electrode pattern 52 on the surface of a ceramic green sheet 51, a step of stacking a plurality of ceramic green sheets 51 on which the internal electrode patterns 52 are formed to form a laminate 50, and a step of press molding the laminate 50 with a pair of pressure plates 71 (71a, 71b).

[0022] The present inventors have discovered a problem in that the conventional PET cushioning material described in Patent Document 1 does not have sufficient conformability to the unevenness between the surface of the ceramic green sheet and the irregularities of the internal electrode pattern, which causes pressure imbalance during press molding using a uniaxial press or a hydrostatic press, resulting in lateral displacement of the ceramic green sheet, or so-called lamination misalignment. This lamination misalignment degrades the properties of the multilayer ceramic capacitor.

[0023] Therefore, the present inventors have conducted extensive research into methods for suppressing the occurrence of stacking misalignment, and as a result have come up with the idea of ​​focusing on the configuration of the main surface of the cushioning material facing the stack in order to improve conformability to steps.

[0024] As described above, the laminate film 10 of this embodiment includes a substrate film 11 and a rubber layer 12 laminated on the substrate film 11 and containing an elastomer as a main component. The amount of deformation in the thickness direction of the laminate film 10 measured by compression test A is 14.5 μm or more. With this configuration, for example, as shown in FIG. 2 , by arranging the rubber layer 12 so that it faces the laminate 50 during press molding, the occurrence of lamination slippage can be suppressed. Specifically, the substrate film 11 improves the handleability of the laminate film 10 itself and serves to uniformly transmit pressure throughout the laminate 50. The rubber layer 12 easily conforms to the unevenness between the surface of the ceramic green sheet 51 and the irregularities of the internal electrode pattern 52, thereby suppressing the occurrence of pressure imbalance. The suppression of pressure imbalance, for example, suppresses lateral displacement of the ceramic green sheet 51. Thus, the laminate film 10 has excellent conformability to unevenness. Therefore, for example, when used as a cushioning material during press molding, the occurrence of lamination slippage can be suppressed. As a result, degradation of the characteristics of the multilayer ceramic capacitor is suppressed.

[0025] The lower limit of the deformation amount in the thickness direction of the laminate film 10 measured by Compression Test A may be 15.0 μm or more. The upper limit of the deformation amount in the thickness direction of the laminate film 10 measured by Compression Test A is, for example, less than 40 μm. The upper limit of the deformation amount may be 39.5 μm or less.

[0026] Fig. 4 is a schematic diagram for explaining compression test A. Measurement of the deformation amount of the laminated film 10 in compression test A can be carried out using a thermomechanical analysis (TMA) device. A specific measurement method will be described with reference to Fig. 4.

[0027] First, a test piece 10A is prepared by cutting out the laminated film 10 (FIG. 4A). The test piece 10A may be, for example, a square or rectangle with sides measuring 5 to 10 mm. Next, the test piece 10A is placed on a stage 81 of a TMA apparatus maintained at 25°C (FIG. 4B). The test piece 10A is positioned so that the second main surface 102 (on the rubber layer 12 side) faces away from the surface of the stage 81. Next, while the stage 81 is maintained at 25°C, a cylindrical compression probe 82 with a diameter of 1 mm is used to gradually compress the test piece 10A in its thickness direction at a compression rate of 50 g / min while increasing the load. When the pressure reaches 5 MPa, the deformation amount λ in the thickness direction of the test piece 10A is measured (FIG. 4C). The deformation amount λ can be determined by the TMA apparatus as the distance between the second main surface 102 of the test piece 10A and the tip of the compression probe 82.

[0028] 1 , a rubber layer 12 is provided on one main surface of the base film 11. However, rubber layers 12 may be provided on both main surfaces of the base film 11. That is, both the first main surface 101 and the second main surface 102 of the laminate film 10 may be formed of rubber layers 12.

[0029] The base film 11 typically contains a resin as a main component, but may also be made of only a resin.

[0030] The resin content of the base film 11 is, for example, 50% by weight or more. The resin content of the base film 11 may be 70% by weight or more, 80% by weight or more, 90% by weight or more, or even 95% by weight or more. The upper limit of the resin content of the base film 11 is, for example, 100% by weight.

[0031] Examples of resins used for the base film 11 include polyester resins, polyimide resins, and polyolefin resins. Among these, polyester resins are preferably used. The resin may contain polyester resin as a main component.

[0032] The polyester resin includes, for example, polyethylene terephthalate, polyethylene naphthalate, etc. The polyester resin may contain polyethylene terephthalate. As the polyester resin, one or a combination of two or more selected from these may be used.

[0033] The resin used for the base film 11 may be polyethylene terephthalate. By using polyethylene terephthalate as the resin used for the base film 11, for example, the adhesiveness to the rubber layer 12 can be improved.

[0034] In addition to the resin, the substrate film 11 may contain additives such as pigments, dyes, ultraviolet absorbers, light stabilizers, antioxidants, and plasticizers.

[0035] As described above, the rubber layer 12 contains an elastomer as a main component, but may also be made of only an elastomer.

[0036] The elastomer content in the rubber layer 12 is, for example, 50% by weight or more. The elastomer content in the rubber layer 12 may be 70% by weight or more, 80% by weight or more, 90% by weight or more, or even 95% by weight or more. The upper limit of the elastomer content in the rubber layer 12 is, for example, 100% by weight.

[0037] The elastomer used in the rubber layer 12 is a rubber-like elastic body. The elastomer may be a thermosetting elastomer or a thermoplastic elastomer. The elastomer is not particularly limited. Examples of the elastomer include silicone rubber, fluororubber, urethane rubber, ethylene-propylene-diene rubber (EPDM), acrylic rubber, and natural rubber. As the elastomer, one or a combination of two or more selected from these may be used. Among these, silicone rubber is preferably used. The elastomer may contain silicone rubber.

[0038] The elastomer used in the rubber layer 12 may be silicone rubber. By using silicone rubber as the elastomer used in the rubber layer 12, the conformability of the laminated film 10 to unevenness can be further improved.

[0039] The rubber layer 12 may contain additives such as pigments, dyes, ultraviolet absorbers, light stabilizers, antioxidants, and plasticizers in addition to the elastomer.

[0040] The thickness 10t of the laminate film 10 may be, for example, in the range of 50 μm or more and 300 μm or less. The lower limit of the thickness 10t of the laminate film 10 may be 55 μm, 60 μm, 65 μm, or even 70 μm. The upper limit of the thickness 10t of the laminate film 10 may be 280 μm, 250 μm, 230 μm, or even 200 μm.

[0041] The thickness 10t of the laminate film 10 can be determined by measuring the thickness of the laminate film 10 at any five points on the laminate film 10 using, for example, a dial gauge, and averaging these measurements. The thickness 10t of the laminate film 10 can also be determined by measuring the thickness of the laminate film 10 at any five points on a scanning electron microscope (SEM) image of a cross section of the laminate film 10 and averaging these measurements. The thickness 11t of the base film 11 and the thickness 12t of the rubber layer 12 can be determined in the same manner.

[0042] The thickness 12t of the rubber layer 12 may be smaller than the thickness 11t of the base film 11 or may be larger than the thickness 11t of the base film 11. The thickness 12t of the rubber layer 12 may be equal to the thickness 11t of the base film 11.

[0043] The ratio (12t / 11t) of the thickness 12t of the rubber layer 12 to the thickness 11t of the base film 11 is preferably 0.35 or more and 3.5 or less. With this configuration, the above-mentioned effects are more easily obtained.

[0044] The lower limit of the thickness ratio (12t / 11t) may be 0.4, 0.45, or even 0.5. The upper limit of the thickness ratio (12t / 11t) may be 3.0, 2.5, 2.0, 1.5, or even 1.0.

[0045] The thickness 11t of the base film 11 can be, for example, in the range of 30 μm or more and 150 μm or less. When the thickness 11t of the base film 11 is in the above range, for example, the laminate film 10 itself can have sufficient handleability. The lower limit of the thickness 11t of the base film 11 may be 35 μm, 40 μm, 45 μm, or even 50 μm. The upper limit of the thickness 11t of the base film 11 may be 140 μm, 130 μm, 120 μm, 110 μm, or even 100 μm.

[0046] The thickness 12t of the rubber layer 12 can be, for example, in the range of 10 μm to 200 μm. When the thickness 12t of the rubber layer 12 is in the above range, pressure is easily transmitted to the laminate 50 during press molding in the manufacturing method of the multilayer ceramic capacitor, and therefore sufficient integration of the laminate 50 is easily achieved. The lower limit of the thickness 12t of the rubber layer 12 may be 15 μm or 20 μm. The upper limit of the thickness 12t of the rubber layer 12 may be 180 μm, 170 μm, 160 μm, or even 150 μm.

[0047] In the laminated film 10, the tensile modulus of a test piece of the rubber layer 12 measured by the tensile test described below is preferably 6.5 MPa or more and 30 MPa or less.

[0048] <Tensile Test> A test specimen is obtained by punching out the rubber layer 12 with a No. 3 tensile dumbbell-shaped test specimen punching blade. A tensile test of the test specimen is carried out in accordance with JIS K7127:1999 using a tensile tester under conditions of 25°C and 50% RH at a tensile speed of 200 mm / min.

[0049] If the tensile modulus of the test piece of the rubber layer 12 measured by a tensile test is 6.5 MPa or more and 30 MPa or less, for example, during press molding in the manufacturing method of the multilayer ceramic capacitor, the rubber layer 12 forming the second main surface 102 of the laminated film 10 is likely to conform to the steps between the surface of the ceramic green sheet 51 and the unevenness of the internal electrode pattern 52.

[0050] The lower limit of the tensile modulus of the test piece of the rubber layer 12 may be 6.8 MPa or 7.1 MPa. The upper limit of the tensile modulus of the test piece of the rubber layer 12 may be 28 MPa or 25 MPa.

[0051] 5 is a schematic diagram for explaining the tensile test. A specific method for measuring the tensile modulus of the test piece of the rubber layer 12 by the tensile test will be described with reference to FIG.

[0052] First, a test piece 12A of the rubber layer 12 is prepared. The test piece 12A can be prepared, for example, as follows. First, a raw material solution containing an elastomer as a main component is applied onto a PET film (e.g., Lumirror S10, manufactured by Toray Industries, Inc.) to form a coating film. The coating film is dried at 90°C for 30 seconds. The dried film is sintered at 180°C for 2 minutes. The PET film is removed from the sintered film. The rubber sheet thus obtained is punched out with a tensile dumbbell-shaped test piece punching blade to obtain the test piece 12A. The composition of the test piece 12A is the same as that of the rubber layer 12 constituting the laminate film 10. Next, in a tensile tester 90 (e.g., a desktop precision universal testing machine, Autograph AGS-X, manufactured by Shimadzu Corporation) shown in FIG. 5, the test piece 12A is clamped to the measurement head 91 with a chuck distance of 35 mm so that the longitudinal direction is vertical. A tensile test is performed by applying stress in the tensile direction to the clamped test piece 12A from the load generating unit 92 via the probe 93 at a tensile speed of 200 mm / min. At this time, the temperature of the test piece 12A is controlled to 25°C by the temperature control unit 94. A stress-strain curve (SS curve) can be obtained from the detected values ​​of the displacement detection unit 95. From the SS curve, the stress σ1 (MPa) at strain ε1 = 0.0005 (0.05%) and the stress σ2 (MPa) at strain ε2 = 0.0025 (0.25%) are determined. From these values, the tensile modulus E (MPa) can be calculated using the following equation (1):

[0053] E=(σ2-σ1) / (ε2-ε1)...(1)

[0054] In the laminate film 10, when the pressure test described below is performed on the laminate film 10 using pressure-sensitive paper that changes color when subjected to pressure and a 20 mm square stainless steel (SUS) plate-like member having a first main surface with a 1 mm wide and 0.010 mm deep groove formed therein and a flat second main surface, and the pressure-sensitive paper is then binarized, it is preferable that the ratio of the area of ​​dark portions to the area of ​​a circle having a radius of 5 mm from a point corresponding to the center of the plate-like member in the binarized image be 95% or more. Such laminate film 10 has excellent step-conforming properties, and therefore can further suppress the occurrence of lamination slippage during press molding in, for example, a method of manufacturing a multilayer ceramic capacitor.

[0055] <Pressure Test> Pressure-sensitive paper, laminated film 10, and a plate-like member made of SUS are stacked in this order between a lower pressure plate and an upper pressure plate. The laminated film 10 is arranged so that the rubber layer 12 faces the first main surface of the plate-like member. A pressure of 95 MPa is applied in the thickness direction from the upper pressure plate at a temperature of 25°C and maintained for 1 minute.

[0056] The ratio of the area of ​​the dark areas to the area of ​​a circle with a radius of 5 mm from a point corresponding to the center of the plate-like member in the binary image may be 96% or more, 97% or more, 98% or more, or even 99% or more.

[0057] Fig. 6 is a schematic diagram for explaining the pressure test. A specific method for evaluating the ratio of the area of ​​dark areas to the area of ​​a circle with a radius of 5 mm in a binarized image of pressure-sensitive paper obtained by the pressure test will be described with reference to Fig. 6.

[0058] First, a 20 mm square SUS plate-shaped member 62 is prepared (see FIG. 6A ). The plate-shaped member 62 has a first main surface 621 with a groove 62g 1 mm wide and 0.010 mm deep formed therein and a flat second main surface 622. The groove 62g has a rectangular cross section and is formed in a cross shape in plan view, dividing the first main surface 621 into four equal squares. The center 62p of the plate-shaped member 62 is located at the intersection of the cross of the groove 62g. A test piece 10B is prepared by cutting out the laminated film 10. The shape of the test piece 10B is square. The area of ​​the main surface of the test piece 10B is larger than the area of ​​the main surface of the plate-shaped member 62. For example, Fujifilm's Prescale (High Pressure HS) can be used as the pressure-sensitive paper 61 that changes color when subjected to pressure. Next, the pressure-sensitive paper 61, test piece 10B, and plate-like member 62 are stacked in this order between the lower pressure plate 72b and the upper pressure plate 72a, both maintained at 25°C. The test piece 10B is positioned so that the second main surface 102 on the rubber layer 12 side of the test piece 10B faces the first main surface 621 of the plate-like member 62 (see FIG. 6B). Next, while the lower pressure plate 72b and the upper pressure plate 72a are maintained at 25°C, a pressure of 95 MPa is applied from the upper pressure plate 72a in the thickness direction and maintained for one minute. After maintaining this for one minute, the press is released and the pressure-sensitive paper 61 is removed. The pressure-sensitive paper 61 is then binarized to obtain a binarized image. The percentage of the area of ​​the dark areas in the binarized image relative to the area of ​​a circle with a radius of 5 mm from the point corresponding to the center 62p of the plate-like member 62 is determined. In the binarized image, high density portions (dark portions) on the pressure-sensitive paper 61 are represented by black pixels, and low density portions (light portions) are represented by white pixels.

[0059] In laminate film 10, the amount of deformation in the thickness direction measured by compression test A is defined as λ1, and the amount of deformation in the thickness direction measured by compression test A after performing the following compression test B five times is defined as λ2. In this case, it is preferable that the rate of change R expressed as (λ1 - λ2) / λ1 x 100 is 25% or less. Such laminate film 10 can maintain excellent conformability to unevenness, and therefore can suppress the occurrence of lamination slippage even when used repeatedly, for example, in press molding in a manufacturing method for a multilayer ceramic capacitor.

[0060] <Compression Test B> A laminated film 10 and a 2 mm thick, 50 mm square SUS plate-like member were stacked in this order between a lower pressure plate and an upper pressure plate, with the rubber layer 12 of the laminated film 10 facing the plate-like member. A pressure of 60 MPa was applied in the thickness direction from the upper pressure plate at a temperature of 90°C and maintained for 10 minutes.

[0061] The lower limit of the rate of change R is, for example, 0.5%. The upper limit of the rate of change R may be 24%, 23%, or even 21%.

[0062] 7 is a schematic diagram for explaining the compression test B. A specific method for determining the rate of change R will be described with reference to FIGS.

[0063] First, a test piece 10A is prepared by cutting out the laminated film 10 (FIG. 4A). The shape of the test piece 10A is, for example, a square or rectangle with sides of 150 to 170 mm. The deformation amount λ1 in the thickness direction of the test piece 10A in compression test A is measured using a TMA device according to the method described above (FIG. 4C).

[0064] Next, a 2 mm thick, 50 mm square SUS plate-shaped member 65 is prepared. The area of ​​the main surface of the plate-shaped member 65 is smaller than that of the test piece 10A. Next, the test piece 10A and the plate-shaped member 65 are stacked in this order from bottom to top between a lower pressure plate 72b and an upper pressure plate 72a maintained at 90°C. The test piece 10A and the plate-shaped member 65 are arranged so that the second main surface 102 on the rubber layer 12 side faces the plate-shaped member 65 (Figure 7). Next, while the upper pressure plate 72a and the lower pressure plate 72b are maintained at 90°C, a pressure of 60 MPa is applied in the thickness direction from the upper pressure plate 72a and maintained for 10 minutes. After maintaining the temperature for 10 minutes, the press is released. This compression test B is repeated five times. After repeating compression test B five times, the test piece 10A is left to cool to room temperature.

[0065] After the test piece 10A is allowed to cool to room temperature, the deformation amount λ2 in the thickness direction of the test piece 10A in the compression test A is measured using the TMA device by the method described above (FIG. 4C). From the measured deformation amounts λ1 and λ2, the rate of change R expressed as (λ1-λ2) / λ1×100 can be calculated.

[0066] The rubber layer 12 of the laminated film 10 was measured by a solid-state NMR method. 1 Relaxation time T of H 2H ( 1 H spin-spin relaxation time T 2H ) may be in the range of 60 ms to 200 ms. 2H can be used as an index of the hardness of the resin. 2H The longer the relaxation time T 2H When the thickness is within the above range, for example, during press molding in the manufacturing method of the multilayer ceramic capacitor, the rubber layer 12 forming the second main surface 102 of the laminated film 10 can easily conform to the steps between the surface of the ceramic green sheet 51 and the unevenness of the internal electrode pattern 52.

[0067] Relaxation time T of the rubber layer 12 2H The lower limit of the relaxation time T of the rubber layer 12 may be 70 ms, 80 ms, or even 90 ms. 2H The upper limit may be 190 ms, 180 ms, 170 ms, or even 160 ms.

[0068] The adhesive strength of the laminate film 10 to a stainless steel (SUS) plate-like member, as measured by the following adhesive strength test, may be 0.1 N / 20 mm or less. The laminate film 10 having such a configuration is likely to achieve excellent conformability to unevenness and excellent handleability.

[0069] <Adhesion Strength Test> A laminate film 10 cut to a width of 20 mm was laminated on a polished SUS plate-like member. The laminate film 10 was placed so that the rubber layer 12 of the laminate film 10 faced the polished main surface of the plate-like member. A rubber-coated roller weighing 2 kg was moved back and forth once on the laminate film 10 to press the laminate film 10 and the plate-like member together, and the laminate film 10 was then left to stand for 20 to 40 minutes in an environment of 23°C. A tensile tester was then used to measure the force required to peel the laminate film 10 at an angle of 180° at a speed of 300 mm / min. The measured value was taken as the adhesive strength of the laminate film 10 to the SUS plate-like member.

[0070] The upper limit of the adhesive strength of the laminate film 10 to a SUS plate-like member may be 0.09 N / 20 mm, 0.08 N / 20 mm, 0.07 N / 20 mm, or even 0.06 N / 20 mm. The lower limit of the adhesive strength of the laminate film 10 to a SUS plate-like member is, for example, 0.04 N / 20 mm. The lower limit of the adhesive strength of the laminate film 10 to a SUS plate-like member may be 0.05 N / 20 mm.

[0071] The laminate film 10 may be colored. For example, different colors may be imparted depending on the thickness 10t of the laminate film 10. By imparting different colors depending on the thickness 10t, it is possible to avoid mixing up the laminate films 10, thereby improving handleability. The method for coloring the laminate film 10 is not particularly limited. For example, the laminate film 10 may be colored by providing a printed layer between the base film 11 and the rubber layer 12. The laminate film 10 may be colored by mixing a pigment into the raw material of the base film 11 or the raw material of the rubber layer 12.

[0072] The shape of the laminate film 10 is not particularly limited. When viewed from a direction perpendicular to the main surface, the laminate film 10 may be a polygon including a rectangle and a square, a circle (including an approximately circle), or an ellipse (including an approximately ellipse). For example, when used as a cushioning material for press molding, the shape of the laminate film 10 may be a rectangle or a square.

[0073] As described above, the laminate film 10 is used, for example, as a cushioning material during press molding in the manufacturing method of a multilayer ceramic capacitor. However, the use of the laminate film 10 is not limited to this. In addition to being a cushioning material, the laminate film 10 may also be used, for example, as a release material or a sealing material (anti-slip material) during press molding. The laminate film 10 may also be used as a protective material for protecting other components, or as a filler for filling gaps between other components.

[0074] [Method for Producing Laminated Film] The laminated film 10 described above can be produced, for example, by the following method.

[0075] The laminated film 10 of FIG. 1 can be produced by forming a rubber layer 12 on a substrate film 11. For example, a commercially available PET film (e.g., Lumirror S10 manufactured by Toray Industries, Inc.) can be used as the substrate film 11. The rubber layer 12 can be produced, for example, as follows. First, a raw material solution containing an elastomer as a main component is applied to the substrate film 11 to form a coating film. The coating film is dried at 90°C for 30 seconds. The dried film is sintered at 180°C for 2 minutes. In this way, the rubber layer 12 can be produced on the substrate film 11. The method for applying the raw material solution is not particularly limited. For example, the raw material solution may be applied to the surface of the substrate film 11 using a bar coater.

[0076] Before forming the rubber layer 12, a primer may be applied to the surface of the substrate film 11 to form a primer layer. The provision of the primer layer can improve adhesion between the substrate film 11 and the rubber layer 12. The composition of the primer is not particularly limited. For example, when silicone rubber is used as the elastomer, a silicone-based primer can be suitably used. The thickness of the primer layer is not particularly limited, but is typically in the range of 0.01 μm to 1 μm, and preferably in the range of 0.1 μm to 1 μm. The primer layer can be formed, for example, by applying a primer to the surface of the substrate film 11 and then drying it at 150°C for 1 minute.

[0077] [Film Member] An example of the film member of the present invention is shown in Fig. 3. The film member 20 in Fig. 3 includes the laminated film 10 described above.

[0078] 3 further includes a release liner 21, and the release liner 21 is bonded to the rubber layer 12 of the laminated film 10. That is, the release liner 21 is bonded to the second main surface 102 of the laminated film 10 on the rubber layer 12 side.

[0079] As shown in Figure 3, the release liner 21 may have a tab 22 that protrudes outward from the outer periphery of the laminate film 10 when viewed perpendicularly to the main surface of the laminate film 10. By gripping the tab 22, the film member 20 can easily place the laminate film 10 on the surface of an object. The release liner 21 is usually removed when the laminate film 10 is used. The release liner 21 may be the same as the base film 11 of the laminate film 10, for example.

[0080] Although not shown in the figure, when a rubber layer 12 is provided on both main surfaces of the base film 11 in the laminate film 10, a release liner 21 may be bonded to both the first main surface 101 and the second main surface 102 of the laminate film 10.

[0081] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the examples shown below.

[0082] <Rubber layer 1 Relaxation time T of H 2H Measurement method for the rubber layer of the laminated film 1 Relaxation time T of H 2H ( 1 H spin-spin relaxation time T 2H ) was measured by a solid-state NMR method. The measurement conditions were as follows. (Measurement conditions) Measurement device: AVANCE III 400WB manufactured by Bruker Corporation Probe: Φ4 mm CPMAS Measurement temperature: 23°C Sample tube rotation speed: 5000 Hz Observation nuclei: 1 H (400 MHz) Pulse sequence: Spin Echo 1H90° pulse: 4.2 μs × 1.6 dB (54 W / 300 W) Delay time τ: 1 μs to 100 ms Pulse delay: 20 s Capture time: 0.819 s Number of integrations: 1

[0083] The relaxation behavior is expressed by the following equation, so the rubber layer 1 Relaxation time T of H 2H was calculated by curve fitting.

[0084] Example 1 The laminated film of Example 1 was produced as follows. A PET film (Lumirror (registered trademark) S10, manufactured by Toray Industries, Inc., thickness 50 μm) was used as the substrate film. Silicone adhesive A (DOWSIL (registered trademark) SE1701 LTV W / C, manufactured by Dow-Toray Industries, Inc.) was used as the raw material solution for the rubber layer. Silicone adhesive A, which was formulated with a base material and catalyst in a blend ratio of 10:3, was applied to the surface of a substrate film treated with a silicone-based primer to form a coating film. The coating film was dried at 90°C for 30 seconds, and then sintered at 180°C for 2 minutes. This resulted in the laminated film of Example 1. The thickness of the rubber layer in the laminated film of Example 1 was 20 μm. The thickness of the rubber layer measured by the above-mentioned method was 10:3. 1 Relaxation time T of H 2H was 101 ms.

[0085] [Example 2] Silicone adhesive A was applied to the surface of a substrate film on which an undercoat layer had been formed, with the coating thickness varied from that of Example 1, to form a coating film. The coating film was dried at 90°C for 30 seconds, and then the dried film was sintered at 180°C for 2 minutes. Except for this, the laminated film of Example 2 was produced in the same manner as Example 1. In the laminated film of Example 2, the thickness of the rubber layer was 35 μm. The thickness of the rubber layer measured by the above-mentioned method was 1 Relaxation time T of H 2H was 101 ms.

[0086] [Example 3] Silicone adhesive A was applied to the surface of a substrate film on which an undercoat layer had been formed, with the coating thickness varied from that of Example 1, to form a coating film. The coating film was dried at 90°C for 30 seconds, and then the dried film was sintered at 180°C for 2 minutes. Except for this, the laminated film of Example 3 was produced in the same manner as Example 1. In the laminated film of Example 3, the thickness of the rubber layer was 50 μm. The thickness of the rubber layer measured by the above-mentioned method was 1 Relaxation time T of H 2H was 101 ms.

[0087] [Example 4] A PET film (Lumirror S10, manufactured by Toray Industries, Inc., thickness 100 μm) was used as the substrate film. Silicone adhesive A was applied to the surface of the substrate film on which an undercoat layer had been formed, with the coating thickness changed from that of Example 1, to form a coating film. The coating film was dried at 90°C for 30 seconds, and then the dried film was sintered at 180°C for 2 minutes. Except for these, the laminated film of Example 4 was produced in the same manner as Example 1. In the laminated film of Example 4, the thickness of the rubber layer was 50 μm. The thickness of the rubber layer measured by the above-mentioned method was 1 Relaxation time T of H 2H was 101 ms.

[0088] [Example 5] Silicone adhesive A was applied to the surface of a substrate film having an undercoat layer formed thereon, with the coating thickness varied from that of Example 1, to form a coating film. The coating film was dried at 90°C for 30 seconds, and then the dried film was sintered at 180°C for 2 minutes. Except for this, the laminated film of Example 5 was produced in the same manner as Example 1. In the laminated film of Example 5, the thickness of the rubber layer was 100 μm. The thickness of the rubber layer measured by the above-mentioned method was 1 Relaxation time T of H 2H was 101 ms.

[0089] [Example 6] Silicone adhesive A was applied to the surface of a substrate film on which an undercoat layer had been formed, with the coating thickness varied from that of Example 1, to form a coating film. The coating film was dried at 90°C for 30 seconds, and then the dried film was sintered at 180°C for 2 minutes. Except for this, the laminated film of Example 6 was produced in the same manner as Example 1. In the laminated film of Example 6, the thickness of the rubber layer was 150 μm. The thickness of the rubber layer measured by the above-mentioned method was 1 Relaxation time T of H 2H was 101 ms.

[0090] [Example 7] A silicone adhesive A containing a base material and a catalyst in a compounding ratio of 10:1 was applied to the surface of a substrate film on which an undercoat layer had been formed, to form a coating film. The coating film was dried at 90°C for 30 seconds, and then the dried film was sintered at 130°C for 2 minutes. Except for this, the laminated film of Example 7 was produced in the same manner as in Example 1. In the laminated film of Example 7, the thickness of the rubber layer was 100 μm. The thickness of the rubber layer measured by the above-mentioned method was 1 Relaxation time T of H 2H was 109 msec.

[0091] [Example 8] Silicone adhesive A was applied to the surface of a substrate film on which a primer layer had been formed, to form a coating film. The coating film was dried at 90°C for 30 seconds, and then the dried film was sintered at 180°C for 2 minutes. The sintered film was further cured at 130°C for 24 hours. Except for this, the laminated film of Example 8 was produced in the same manner as in Example 1. In the laminated film of Example 8, the thickness of the rubber layer was 100 μm. The thickness of the rubber layer measured by the above-mentioned method was 1 Relaxation time T of H 2H was 96 msec.

[0092] [Example 9] Silicone adhesive B (DOWSIL (registered trademark) SE4410, manufactured by Dow-Toray Industries, Inc.) was used as the raw material solution for the rubber layer. Silicone adhesive B was applied to the surface of a substrate film on which an undercoat layer had been formed, to form a coating film. The coating film was dried at 90°C for 30 seconds, and then the dried film was sintered at 180°C for 2 minutes. Except for these, the laminated film of Example 9 was produced in the same manner as in Example 1. In the laminated film of Example 9, the thickness of the rubber layer was 50 μm.

[0093] [Example 10] Liquid silicone rubber C (Silopren (registered trademark) LSR7080, manufactured by Momentive) was used as the raw material solution for the rubber layer. Liquid silicone rubber C was applied to the surface of a substrate film on which an undercoat layer had been formed, to form a coating film. The coating film was dried at 90°C for 30 seconds, and then the dried film was sintered at 180°C for 2 minutes. Except for these, the laminated film of Example 10 was produced in the same manner as in Example 1. In the laminated film of Example 10, the thickness of the rubber layer was 50 μm.

[0094] [Example 11] Liquid silicone rubber D (Silopren LSR7030, manufactured by Momentive) was used as the raw material solution for the rubber layer. Liquid silicone rubber D was applied to the surface of a substrate film on which an undercoat layer had been formed, to form a coating film. The coating film was dried at 90°C for 30 seconds, and then the dried film was sintered at 180°C for 2 minutes. Except for these, the laminated film of Example 11 was produced in the same manner as in Example 1. In the laminated film of Example 11, the thickness of the rubber layer was 50 μm. The thickness of the rubber layer measured by the above-mentioned method was 1 Relaxation time T of H 2H was 154 msec.

[0095] [Comparative Example 1] The PET film (Lumirror S10, manufactured by Toray Industries, Inc., thickness 50 μm) used as the base film in Example 1 was used as the film of Comparative Example 1. That is, the film of Comparative Example 1 did not have a rubber layer and was composed of only the base film.

[0096] Comparative Example 2 A film of Comparative Example 2 was produced as follows. A PET film (Lumirror S10, manufactured by Toray Industries, Inc., thickness 50 μm) was used as the substrate film. Silicone adhesive A (DOWSIL SE1701 LTV, manufactured by Dow-Toray Industries, Inc.) was used as the raw material solution for the rubber layer. Silicone adhesive A was applied to the surface of a substrate film on which no undercoat layer was to be formed, to form a coating film. The coating film was dried at 90°C for 30 seconds, and then the dried film was sintered at 180°C for 2 minutes, after which the rubber layer was peeled off from the substrate film. This yielded the film of Comparative Example 2. That is, the film of Comparative Example 2 did not have a substrate film and was composed only of a rubber layer. The thickness of the film of Comparative Example 2 was 50 μm. The thickness of the rubber layer measured by the above-mentioned method was 100 μm. 1 Relaxation time T of H 2H was 101 ms.

[0097] [Comparative Example 3] Silicone adhesive A was applied to the surface of a substrate film on which an undercoat layer had been formed, to form a coating film. The coating film was dried at 90°C for 30 seconds, and then the dried film was sintered at 180°C for 2 minutes. Except for this, the film of Comparative Example 3 was produced in the same manner as in Example 1. In the film of Comparative Example 3, the thickness of the rubber layer was 15 μm. The thickness of the rubber layer measured by the above-mentioned method was 1 Relaxation time T of H 2H was 101 ms.

[0098] [Example 12] A PET film (Lumirror S10, manufactured by Toray Industries, Inc., thickness 100 μm) was used as the substrate film. Silicone adhesive A was applied to the surface of the substrate film on which the undercoat layer had been formed, with the coating thickness changed from that of Example 1, to form a coating film. The coating film was dried at 90°C for 30 seconds, and then the dried film was sintered at 180°C for 2 minutes. Except for these, the laminated film of Example 12 was produced in the same manner as Example 1. In the laminated film of Example 12, the thickness of the rubber layer was 100 μm. The thickness of the rubber layer measured by the above-mentioned method was 1 Relaxation time T of H 2H was 101 ms.

[0099] [Example 13] A silicone adhesive A containing a base material and a catalyst in a compounding ratio of 10:1 was applied to the surface of a substrate film on which an undercoat layer had been formed, to form a coating film. The coating film was dried at 90°C for 30 seconds, and then the dried film was sintered at 130°C for 2 minutes. Except for this, the laminated film of Example 13 was produced in the same manner as in Example 12. In the laminated film of Example 13, the thickness of the rubber layer was 100 μm. The thickness of the rubber layer measured by the above-mentioned method was 1 Relaxation time T of H 2H was 109 msec.

[0100] [Example 14] Silicone adhesive A was applied to the surface of a substrate film on which an undercoat layer had been formed, to form a coating film. The coating film was dried at 90°C for 30 seconds, and then the dried film was sintered at 180°C for 2 minutes. The sintered film was further cured at 130°C for 24 hours. Except for this, the laminated film of Example 14 was produced in the same manner as in Example 12. In the laminated film of Example 14, the thickness of the rubber layer was 100 μm. The thickness of the rubber layer measured by the above-mentioned method was 1 Relaxation time T of H 2H was 96 msec.

[0101] For the laminate films of Examples 1 to 11, Comparative Examples 1 to 3, and Examples 12 to 14, the ratio of the rubber layer thickness to the base film thickness, the tensile modulus of the rubber layer specimen measured by the tensile test, the thickness direction deformation λ1 measured by Compression Test A, the thickness direction deformation λ2 measured by Compression Test A after performing Compression Test B five times, and the ratio of the area of ​​the dark area to the area of ​​a circle with a radius of 5 mm from the point corresponding to the center of the plate-like member in the binarized image of pressure-sensitive paper obtained by the pressure test were evaluated using the methods described above. The rate of change R, expressed as (λ1 - λ2) / λ1 x 100, was calculated from the deformation λ1 and the deformation λ2. The tensile test was conducted after preparing rubber layer specimens using each raw material solution using the method described above. The thickness of the rubber layer specimen for the tensile test was the same as the thickness of the rubber layer of the laminate film. The results are shown in Tables 1 to 3.

[0102] In Tables 1 to 3, in the evaluation of the ratio of the area of ​​dark areas to the area of ​​a circle with a radius of 5 mm in the binarized image of pressure-sensitive paper obtained by the pressure test, A to C respectively mean the following: A: The ratio of the area of ​​dark areas to the area of ​​the circle is 99% or more. B: The ratio of the area of ​​dark areas to the area of ​​the circle is 95% or more but less than 99%. C: The ratio of the area of ​​dark areas to the area of ​​the circle is less than 95%.

[0103] FIG. 8 shows an image (a) of pressure-sensitive paper after a pressure test of the laminated film of Example 1, and a diagram (b) showing a circle with a radius of 5 mm in the binarized image obtained by binarizing the image (a). FIG. 9 shows an image (a) of pressure-sensitive paper after a pressure test of the laminated film of Example 5, and a diagram (b) showing a circle with a radius of 5 mm in the binarized image obtained by binarizing the image (a). FIG. 10 shows an image (a) of pressure-sensitive paper after a pressure test of the film of Comparative Example 1, and a diagram (b) showing a circle with a radius of 5 mm in the binarized image obtained by binarizing the image (a). FIG. 11 shows an image (a) of pressure-sensitive paper after a pressure test of the film of Comparative Example 3, and a diagram (b) showing a circle with a radius of 5 mm in the binarized image obtained by binarizing the image (a). Note that in FIGS. 8 to 11, the scales of the images (a) and the binarized images (b) are not the same.

[0104]

[0105]

[0106]

[0107] As shown in Tables 1 to 3, the laminate films of Examples 1 to 14 were evaluated as A or B for the ratio of the area of ​​the dark areas to the area of ​​the circle in the binarized image of the pressure-sensitive paper in the pressure test, demonstrating excellent step-conforming properties. The laminate films of Examples 1 to 14 had a thickness-wise deformation λ1 of 14.5 μm or more as measured by compression test A. In contrast, the films of Comparative Examples 1 and 3, which had a deformation λ1 of less than 14.5 μm, were evaluated as C for the ratio of the area of ​​the dark areas to the area of ​​the circle in the binarized image of the pressure-sensitive paper in the pressure test, demonstrating poor step-conforming properties. The film of Comparative Example 2 was evaluated as A for the ratio of the area of ​​the dark areas to the area of ​​the circle in the binarized image of the pressure-sensitive paper in the pressure test, but due to the absence of a base film, the film itself was prone to sticking and had poor handleability. Furthermore, the film of Comparative Example 2 had an excessively large deformation λ1, resulting in relatively poor pressure transmission. These results demonstrate that a laminate film having a substrate film and a rubber layer containing an elastomer as a main component laminated on the substrate film, and having a thickness direction deformation λ1 of 14.5 μm or more as measured by Compression Test A, has excellent conformability to unevenness. It is presumed that such a laminate film is suitable for suppressing the occurrence of lamination slippage when used as a cushioning material during press molding in a manufacturing method for a multilayer ceramic capacitor, for example.

[0108] As described above, the rubber layer in the laminated films of Examples 1 to 8 and 11 to 14 1 Relaxation time T of H 2H From this result, it is clear that the rubber layer 1 Relaxation time T of H 2H When the value is in the above range, it is considered that the rubber layer of the laminated film can more easily conform to the unevenness.

[0109] The technology of the present invention can be applied, for example, as a buffer material during press molding in the manufacturing method of a multilayer ceramic capacitor.

Claims

1. A laminated film comprising a base film and a rubber layer containing an elastomer as a main component laminated on the base film, wherein the amount of deformation in the thickness direction measured by the following compression test A is 14.5 μm or more. <Compression test A> A pressure of 5 MPa is applied in the thickness direction from the rubber layer side of the laminated film using a cylindrical compression probe with a diameter of 1 mm at a temperature of 25°C and a compression rate of 50 g / min.

2. The laminated film according to claim 1, wherein the elastomer includes silicone rubber.

3. The laminated film according to claim 1, wherein the base film contains a polyester resin as a main component.

4. The laminated film according to claim 3, wherein the polyester resin contains polyethylene terephthalate.

5. The laminated film according to claim 1, wherein the ratio of the thickness of the rubber layer to the thickness of the base film is 0.35 or more and 3.5 or less.

6. The laminated film according to claim 1, wherein the tensile modulus of a test piece measured by the following tensile test is 6.5 MPa or more and 30 MPa or less. <Tensile test> A test piece is obtained by punching out the rubber layer with a No. 3 tensile dumbbell-shaped test piece punching blade. In accordance with JIS K7127:1999, a tensile test of the test piece is carried out using a tensile tester at a tension speed of 200 mm / min under conditions of 25°C and 50% RH.

7. The laminate film according to claim 1, wherein the pressure-sensitive paper that changes color when subjected to pressure and a 20 mm square stainless steel plate member having a first main surface with a 1 mm wide, 0.010 mm deep groove formed thereon and a flat second main surface are subjected to the following pressure test. When the pressure-sensitive paper is then binarized, the ratio of the area of ​​dark areas to the area of ​​a circle with a radius of 5 mm from the point corresponding to the center of the plate member in the binarized image is 95% or more. <Pressure Test> The pressure-sensitive paper, the laminate film, and the plate member are laminated in this order from bottom to top between a lower pressure plate and an upper pressure plate, with the rubber layer of the laminate film facing the first main surface of the plate member. A pressure of 95 MPa is applied in the thickness direction from the upper pressure plate at a temperature of 25°C and maintained for one minute.

8. The laminate film according to claim 1, wherein the deformation in the thickness direction measured in Compression Test A is defined as λ1, and the deformation in the thickness direction measured in Compression Test A after performing Compression Test B described below five times is defined as λ2. The rate of change, expressed as (λ1 - λ2) / λ1 x 100, is 25% or less. <Compression Test B> The laminate film and a 2 mm thick, 50 mm square stainless steel plate-like member are laminated in this order from bottom to top between a lower pressure plate and an upper pressure plate. The rubber layer of the laminate film and the plate-like member are positioned so that they face each other. A pressure of 60 MPa is applied in the thickness direction from the upper pressure plate at a temperature of 90°C, and maintained for 10 minutes.

9. The laminated film according to claim 1, which is used as a cushioning material, a release material, a sealing material, a protective material, or a filler.

Images