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CN-118124231-B - Release film for multilayer ceramic capacitor

CN118124231BCN 118124231 BCN118124231 BCN 118124231BCN-118124231-B

Abstract

The release film comprises a back coating layer, a substrate layer, a coating layer and a release layer, wherein the back coating layer is arranged on one surface of the substrate layer, the coating layer is arranged on the other surface of the substrate layer, the release layer is arranged on the coating layer, the surface roughness Ra of the connection surface of the substrate layer and the coating layer is less than or equal to 50nm and Rp is less than or equal to 500nm, the transverse thermal expansion coefficient of the substrate is less than or equal to 99 multiplied by 10 ‑6 K ‑1 , and the surface roughness Ra of the connection surface of the coating layer and the release layer is less than or equal to 20nm and Rp is less than or equal to 200nm. The invention adopts the evaporation coating method to plate the silicon dioxide coating layer on the surface of the substrate of the release film of the multilayer ceramic capacitor, thereby realizing the pit filling effect and greatly reducing the roughness of the substrate layer.

Inventors

  • PANG XIAO
  • LIU YULEI
  • HUANG YONGHUA
  • LI CHAO
  • HU WANYUN
  • ZHOU RAN
  • ZHAO BAOLIANG
  • CHEN ZHONGLIAN

Assignees

  • 合肥乐凯科技产业有限公司

Dates

Publication Date
20260508
Application Date
20231215

Claims (7)

  1. 1. A release film for a multilayer ceramic capacitor is characterized by comprising a back coating, a substrate layer, a coating layer and a release layer, wherein one surface of the substrate layer is provided with the back coating, the other surface of the substrate layer is provided with the coating layer, the release layer is arranged on the coating layer, the surface roughness Ra of the connection surface of the substrate layer and the coating layer is less than or equal to 50nm and Rp is less than or equal to 500nm, the transverse thermal expansion coefficient of the substrate is less than or equal to 99 multiplied by 10 -6 K -1 , and the surface roughness Ra of the connection surface of the coating layer and the release layer is less than or equal to 20nm and Rp is less than or equal to 200nm; The coating layer is a silicon dioxide coating layer, and the thickness of the coating is not more than 500nm; The release layer is a polyacrylate non-silicon release layer, and the thickness of the release layer is 0.05-0.3 mu m.
  2. 2. The release film for a multilayer ceramic capacitor according to claim 1, wherein the thickness of the base material layer is 19-50 μm, and the base material layer is biaxially oriented polyethylene terephthalate film.
  3. 3. The release film for a multilayer ceramic capacitor according to claim 2, wherein the substrate layer has an AB two-layer structure, the surface of the layer A has a low roughness surface with a thickness of 0.3-2 μm, the surface of the layer B has a corona surface, inert particles with two particle diameters are added in the layer A, and no inert particles are added in the layer B.
  4. 4. The release film for a multilayer ceramic capacitor according to claim 3, wherein 30nm to 300nm particles account for 50%,500nm to 800nm particles account for 50% and the total addition amount of particles is 5000ppm to 50000ppm in the layer A structure.
  5. 5. The release film for a multilayer ceramic capacitor according to claim 4, wherein the particles in the A-layer structure are a combination of 30nm and 800nm diameter particles.
  6. 6. The release film for a multilayer ceramic capacitor according to claim 3, wherein the inert particles in the A-layer structure are any one or a combination of a plurality of titanium oxide, silicon oxide, barium sulfate, aluminum oxide, magnesium oxide, calcium carbonate, kaolin, talc, polystyrene resin, acrylic resin, urea resin and melamine resin.
  7. 7. The release film for a multilayer ceramic capacitor according to claim 1, wherein the back coating is a resin layer having an antistatic effect, the antistatic agent is one of a quaternary ammonium salt antistatic agent, a polythiophene antistatic agent, a graphene antistatic agent, and a carbon nanotube antistatic agent, the amount of the antistatic agent added is 2 to 5%, and the resin main body of the back coating is one of melamine resin, polyurethane resin, and acrylic resin.

Description

Release film for multilayer ceramic capacitor Technical Field The invention relates to a release film, in particular to a release film for a multilayer ceramic capacitor. Background In recent years, with the rapid popularization of new energy automobiles and 5G communication, the demand for multilayer ceramic capacitors has been increasing. The multilayer ceramic capacitor has the characteristic of temporarily storing electric energy, is an indispensable electronic element in an electronic circuit, can stabilize current flow, has the number of the multilayer ceramic capacitors in one mobile phone of hundreds and has the number of the multilayer ceramic capacitors in one new energy automobile of thousands. In order to increase the size and capacity of a laminated ceramic capacitor, it is desirable to reduce the thickness of ceramic sheets and laminate them into multiple layers. Most of the ceramic sheets currently in use have a thickness of about 2 to 25 μm. In addition, advanced technology has developed ceramic membranes with a thickness of 2 μm or less. However, as the thickness of the ceramic sheet becomes thinner, the peeling force at the time of peeling the ceramic sheet from the release layer of the release film increases, leading to a new problem of frequent occurrence of peeling failure. Thus, a release film having a lower release force than conventional release films is needed. The general release film used for the conventional label and the like has low release force, but has insufficient release property in the production of the thin ceramic sheet. There is a need for a release film with low force. However, even if a release film having a small peeling force from a ceramic sheet of a specific composition is designed, when the thickness of the sheet is changed, the release force between the ceramic sheet and the release layer of the release film is changed, and therefore the release layer composition of the release film is designed to be most suitable for the ceramic sheet of the specific composition every time. In addition, as the thickness of the ceramic sheet becomes thinner, not only the rough protrusions of the release film release layer surface, but also the irregularities of the release layer surface have a greater influence on the thickness of the ceramic. As the thickness decreases, the release film as a support for the ceramic sheet needs to have higher flatness. At present, the thickness of the release layer is generally about 0.2 mu m, the surface roughness SRz of the common polyester film is generally more than 0.5 mu m, and a required amount of release agent cannot be coated on the bulge, so that the release agent can be coated in a missing way, and the ceramic sheet can be peeled off poorly or even broken. In addition, when the surface of the release film has high bulges, the bulges cause the convex shape of the release layer surface of the release film to be transferred to the ceramic sheet to form concave shapes, and the concave shapes of the parts transferred to the ceramic sheet are shape defects of the ceramic sheet. Such defects become apparent as the thickness of the ceramic sheet becomes thinner, and the high protrusion of the film surface causes concave transfer marks on the ceramic sheet, resulting in inaccurate thickness of the ceramic sheet. Furthermore, when the above concave transfer mark becomes strong, it is likely to become a penetration pinhole instead of a mere dent, and in the worst case, the ceramic sheet may be torn when peeled from the release film. When a ceramic sheet having pinholes is used as a laminated ceramic capacitor, short-circuit failure and insulation resistance failure occur, which is a fatal defect. This requires that the base film of the release film for a multilayer ceramic capacitor must have an extremely low level of roughness, and that the base film must also have excellent thermal stability due to the requirement of the drying process, without having problems of flatness such as tension lines, orange peel, and the like. In addition, the release layer containing a curable silicone resin as a main component is extremely easily charged, and the release charge is large when the ceramic sheet is released. In the production process of the release film, foreign matters such as dust are likely to be adsorbed, and the product quality is seriously affected. Meanwhile, the siliconizing-free requirement in the field of semiconductors is more and more strict, and the silicon transfer condition of the traditional organic silicon release agent has a great influence on the application of products. In the same way, in the production process of the multilayer ceramic capacitor, when the ceramic slurry is coated on the carrier release film to form a film, the solvent of the ceramic slurry needs to be uniformly spread on the release film, which requires that the release film surface has higher surface energy, spreadability and solvent resistance. In the ceramic