JPS6126555A - Manufacture of ceramic green tape - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to a method for producing ceramic green tape used as a constituent material of ceramic capacitors, piezoelectric bodies, IC boards, etc. The present invention relates to a manufacturing method capable of obtaining a tape with high productivity.

[Prior art]

There are three methods for manufacturing ceramic green tape, which is an electronic material: an extrusion method, a calendering method, and a doctor blade method, of which the doctor blade method is currently the mainstream.

This doctor blade method is further subdivided into two methods: a method using a non-aqueous resin binder and a method using a water-based resin binder.In the former method, first a binder such as butyral resin or acrylic resin is used. alcohol,
It is dissolved in an organic solvent such as trichlorethylene or toluene, and mixed with fine ceramic powder for a long time to form a slurry. On the other hand, in the latter method, a binder such as a water-soluble acrylic resin is dissolved in deionized water after adding a small amount of plasticizer and dispersant as necessary, and then mixed with fine ceramic powder for a long time to form a slurry. make it into a shape. Next, the air and gas contained in these slurries are degassed under reduced pressure, and a sheet is drawn to a certain thickness onto a carrier film using a sharp blade called a doctor blade, and the resulting sheet is heated and dried. And you're getting green tape.

[Problem that the invention seeks to solve]

However, since the doctor blade method using a non-aqueous binder uses a large amount of organic solvent, it tends to impair environmental hygiene. ■There is a risk of ignition or explosion due to static electricity during mixing. (2) The manufacturing equipment and organic solvents are expensive, resulting in a cost disadvantage.

On the other hand, in the method using a water-based binder that has been proposed as a solution to these problems, ceramics such as alumina easily form water-containing compounds with water and have a large affinity, so the viscosity of the slurry is significantly different from Newtonian flow, and therefore the slurry The fluidity of the ceramic powder and the dispersibility of the ceramic fine powder deteriorate,
Powder filling becomes incomplete and pinholes and cracks are likely to occur in the product.

In addition, when drying a tape, non-aqueous binders use a stepwise temperature gradient and vapor pressure or azeotropic composition to release the solvent, but when using an aqueous binder, the internal water evaporates poorly and the drying speed increases. is 4 to 5 times slower than non-aqueous systems.

Therefore, the present invention provides a new manufacturing method that solves these problems without losing the soaked properties of ceramic green tape.

[Means for solving problems]

In order to solve the above problem, the present invention uses a resin that is cured by ionizing radiation as a binder. That is, 10 to 50 parts by weight of an ionizing radiation-curable uncured resin is added to 100 parts of fine ceramic powder, and the resulting mixture is kneaded to form a tape shape, which is then irradiated with ionizing radiation. A feature of the present invention is that it is cured.

The above-mentioned ionizing radiation curing type 1 resin refers to a resin that has functional properties or functionality that causes a curing reaction when irradiated with ionizing radiation, such as liquid polybutadiene, polybutadiene acrylate, and spiran. These include a single unsaturated compound such as acrylate, epoxy acrylate, and urethane acrylate, or a mixture containing a reactive monomer having an unsaturated bond in the molecule. If necessary, small amounts of plasticizers and desolators may be added to such materials.

The above-mentioned reactive monomers include diacrylate monomers such as diethylene glycol diacrylate, dimethacrylate monomers such as ethylene glycol dimethacrylate and dipropylene glycol dimethacrylate, trimethylolethane triacrylate, and trimethylol. Triacrylate monomers such as propane triacrylate and trimethylolhexane triacrylate, trimethylolethane trimethacrylate,
Trimethacrylate monomers such as trimethylolpropane trimethacrylate and trimethylol-ruhexane trimethacrylate, as well as triallyl cyanurate,
Examples include triallyl cyanurate, trimethacrylic cyanurate, triallyl isocyanurate, diallyl maleate, diallyl fumarate, and the like.

Next, the ionizing radiation irradiated to the forming tape is ultraviolet rays, α
rays, electron beams, etc. However, since there are problems such as ultraviolet rays having low transmitted energy and alpha rays having a low dose rate, electron beams are preferable from an industrial perspective.

Further, the resin as a binder and the fine ceramic powder are uniformly and sufficiently kneaded by ball milling or roll milling, and the kneaded mixture is formed into a tape shape and irradiated with ionizing radiation. The method for forming the green tape at this time is not particularly limited, but the general doctor blade method, extrusion method, and calender roll method are desirable. In addition, the ionizing radiation irradiation required for curing the tape varies depending on the type of resin and reactive monomer used as the binder and inder, but is approximately 1 to 50 irradiation times.
Mrad, and it is possible to cure the resin sufficiently with irradiation l in this range.

Examples of this invention are listed below.

Example 1] Liquid polybutadiene (Polybd: Idemitsu Petrochemical Co., Ltd. trade name) and triacrylic irisyanurate in a 1:1 ratio
75% by weight of ceramic fine powder mainly composed of alumina is mixed with a mixed resin binder in the proportion of
After adding the binder at a ratio of 333 parts by weight to 00 weight and thoroughly kneading it using a Miki o-ru,
Cut the mixture into a thickness Q of 2 mm using a doctor knife.
It was formed into a sheet. Next, an electron beam with an accelerating voltage of 2 MeV was applied to the formed sheet material in air at 2Q Mrad.
Light'ft L, the resin as a binder was cured.

The obtained green sheet (green tape) had no pinholes or cracks, and the capacitor made from this material exhibited the same performance as a capacitor made from green tape made by the conventional method. In addition, less energy was required to harden the resin during the manufacturing process than in the conventional doctor blade method, and the manufacturing time was shorter than in the doctor blade method using a non-aqueous d-binder.

[Example-2] Functional oligoester acrylate (Aronira, product name of Cus Oligomer Nitoa Gosei Kagaku Co., Ltd.) and spiran acrylate (Spirac, product name of Showa Kobunshi Co., Ltd.) were mixed in 1:
The same fine ceramic powder as in Example-1 was added to the resin binder mixed at a ratio of 1% in the same heavy bottle (1% ceramic fine powder).
The binder was added in an amount of 33.3 parts by weight to 0.00 parts by weight, and the mixture was kneaded to form a sheet-like product with a thickness of 0.2 mm.

Thereafter, the resin binder was cured by irradiating it with a 2MeV electron beam at 25 Mrad in the air in the same manner as in Example-1.

The properties and performance of the obtained green sheet (green tape) were almost the same as in Example-1, and the manufacturing time and energy required for manufacturing were also the same as in Example-1.

〔effect〕

As explained above, the method for manufacturing a ceramic green tape of the present invention uses an ionizing radiation-curable resin as a binder and hardens it by irradiation with ionizing radiation, so that many advantages listed below can be obtained. .

(1) Since no organic solvents are used, there is no need to worry about harming the environment or causing a fire or explosion during manufacturing.

(2) No expensive organic solvent is required. Less energy is required for curing the resin as the L1 binder, which is advantageous in terms of cost.

(3) Productivity is improved because the molded tape is cured in a short time.

(4) Since water is not used for dissolving the binder, which deteriorates the fluidity of the slurry and the dispersibility of the ceramic fine powder,
High quality products without pinholes or cracks are required.

Claims (3)

[Claims] (1) Add 10 to 50 parts by weight of an ionizing radiation-curable uncured resin to 100 parts by weight of fine ceramic powder, knead this, form the resulting mixture into a tape shape, and then irradiate it with ionizing radiation. A method for producing a ceramic green tape, characterized by curing it using a method of manufacturing ceramic green tape. (2) The ionizing radiation curable resin is a single unsaturated compound or a mixture containing a reactive monomer having an unsaturated bond in the molecule.
1) The method for producing the ceramic green tape described in section 1). (3) A small amount of a plasticizer and/or a dispersant is added to the mixture of the ionizing radiation curable resin and the ceramic powder.
2) The method for producing the ceramic green tape described in section 2).