JPH0522561B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing thin-walled ceramic cutlery.

Conventional ceramic cutlery such as scissors and knives are made mainly from zirconia or alumina, mixed with 3 to 10% of crystal growth inhibitors such as magnesia, calcia, ittria, etc. Hydrochloric acid was added as a deflocculating agent to create a slurry with a concentration of 26 to 50%, which was then cast into a plaster mold and fired. Alkaline deflocculants such as a mixture of water glass and silica sol have also been used.

However, by casting, injection molding, or press molding, the thickness of the cutter cannot be reduced to less than 2 mm, and it is not possible to form the blade to an ultra-thin thickness of approximately several μm to 1 mm. In addition, since casting molding uses a split mold, a finishing process is required to remove burrs that occur at the parting line, and even if the finish is sufficiently applied, seams will appear after firing, reducing the product's value.

Therefore, the present invention provides a method that can eliminate the above-mentioned drawbacks and mass-produce blades that are extremely thin and have excellent strength and toughness. The gist of the present invention is to attach a ceramic cutter base material of a ceramic kneaded product or mud with water as the main medium to an organic carrier sheet in the form of a thin film sheet, or after attaching the ceramic cutter base raw material to an organic carrier sheet before drying. While in this state, an organic covering sheet is coated on top of the base material, the sheet-like substrate is sandwiched between the carrier sheet and the covering sheet, and then the carrier sheet and the covering sheet are cut into the shape of a knife or without being cut. A thin-walled ceramic knife characterized in that a knife is obtained by stacking and firing one or more of the base materials without removing one of them, and then cutting the uncut fired base material into a knife shape to obtain a knife. This is a manufacturing method.

To explain the present invention in detail, the main raw material of the present invention is alumina or zirconia or a mixture thereof, to which are added a crystal growth inhibitor such as magnesia and/or a crystal structure converter such as ittria or calcia. It is used as a mixed raw material. The content of the main raw material is 90% by weight or more, but the content does not matter as long as the strength and toughness of the product are high. The method for forming a thin sheet from this ceramic raw material is to first add one or more solvents such as alcohol, toluene, trichloroethylene, and ethyl acetate to water or water in an amount ranging from several percent to 80 percent by weight. The mixture is used as a dispersion medium, and a binder, a plasticizer, and a dispersant are added to the medium to prepare a kneaded product or a base material for the slurry. Ammonium acrylate, acrylic ester, ethyl cellulose, abietic acid resin, polyvinyl butyral or its derivatives are used as binders, and abietic acid derivatives, diethyl acetic acid, polyethylene glycol, phthalic acid are used as plasticizers to impart flexibility. Ester, dibutyl phthalate or its derivatives, etc. are used. Further, as a dispersant, one or more of glycerin, octadecylamine, trichloroacetic acid, oleic acid, menhaden oil, glycerin monooleate, etc. are used.

According to experiments, when using water as a medium or a medium with the above solvent added to 30% or more of water, an aqueous solution, hydrosol, or emulsion of acrylic acid polymer as a binder is good as a binder for ceramic powder. It was hot. However, ammonium acrylate, amines of acrylic esters, etc. may be used as binders. These binders, plasticizers, and dispersants may be selected by using one type or a mixture of two or more of the above listed types, and their blending ratio is 30 to 30 parts of the dispersion medium based on 100 parts of the ceramic composition mixed raw material. 70 parts, dispersant 0.05~3 parts, binder 2~
A good ratio is 25 parts of plasticizer and 3 to 15 parts of plasticizer, but the blending ratio is not limited as long as the molded product is uniform and has plasticity and there are no defects such as breakage during the firing process.

The kneaded product or slurry ceramic base material made in this way is used as a natural or synthetic resin,
Organic sheets made of paper, fiber, rubber, etc.
It is attached to a plate (hereinafter simply referred to as carrier sheet 1) to form a thin sheet-like blade base 2 on the carrier sheet (see FIG. 1). And the substrate 2
An organic film, sheet, or board (hereinafter simply referred to as covering sheet 3
A sheet-like substrate 2 is sandwiched between a carrier sheet 1 and a covering sheet 3.
In this case, the substrate 2 may be coated with the covering sheet 3 at any time as long as the substrate 2 is not dried, but if it is applied early after the substrate raw material is attached, the substrate 2 can be kept at a uniform density. Further, in order to keep the thickness of the base material 2 constant, the upper surface of the base material immediately after being deposited may be leveled with a knife edge 4, or the base material 2 may be passed between rollers 5 while being held between the upper and lower sheets 1 and 3. The base material 2 is then wound around the roller 6 while being held between the upper and lower sheets 1 and 3.

Incidentally, in order to improve the adhesion of the cutlery base 2 to the carrier sheet 1 or to improve the flexibility and uniformity of the cutlery base 2, a slurry coagulant is applied onto the carrier sheet and absorbed. The flocculants include bittern, calcium chloride, aluminum chloride,
A divalent or trivalent chloride or sulfate solution such as Albanysulfate is used. The addition of this coagulant prevents the blade base 2 from shifting or peeling off from the carrier sheet, and also prevents cracking during drying and distortion and change during firing. Note that by adding 0.2 to 10% of natural or synthetic glue such as CMC, MC, PVA, sodium alginate, etc. to this coagulant, the blade base 2 can be more strongly adhered to the carrier sheet 1.

After the base material 2 sandwiched between the upper and lower sheets 1 and 3 dries, if it is fired in this state, the organic upper and lower sheets 1 and 3 will be burned out and the base material 2 will be fired. This is what we get. During this firing, if a large number of sheets are stacked and fired, a dusting powder such as alumina powder or zirconia powder may be sprinkled between each sheet to prevent the sheets from welding to the upper and lower substrates. It is. Note that the substrate 2 may be cut while being held between the upper and lower sheets 1 and 3 before firing.

Further, although the substrate 2 is covered and sandwiched between the upper and lower sheets 1 and 3, it can be sufficiently dried by simply leaving it to dry. At this point, force dry or sheet 1, 3
If the cover sheet 3 is made of a material with good air permeability, or if numerous small holes are provided in the covering sheet 3, the substrate 2 will dry quickly.

As described above, according to the present invention, since the blade base can be formed into a sheet shape on an organic carrier sheet, the base can be made thin, thereby eliminating the non-uniformity of the product caused by non-uniform mixing due to the difference in specific gravity as in the past. It is possible to eliminate the drawbacks such as differences in sharpness depending on the part and make the product homogeneous.Since the blade base is held between the upper and lower sheets, it is easy to uniformize the thickness of the base using rollers, etc. The surface of the substrate coated with the coating becomes smooth, eliminating the need for a final polishing process, and when the coagulant is applied onto the carrier sheet, the blade substrate adheres well to the carrier sheet, making the substrate sheet easier to handle. This has the effect of making it easier to load the material into a setter for firing, and preventing cracking of the base material during drying, as well as preventing distortion and change during firing.

In the present invention, the organic material, thickness, and number of sheets used for the carrier sheet and the covering sheet are also arbitrary. Further, the firing conditions are not limited either, as long as the firing can be performed in an oxidizing, reducing, or neutral atmosphere, and the firing temperature can sinter the ceramic cutlery. If the raw material particle size is sufficiently fine, a sufficiently dense sintered body with high strength and toughness can be obtained by firing at 1100 to 1610°C.

In addition, in order to form a thin ceramic knife shape and produce a knife without warping or distortion, the ceramic molded base must be supported throughout the entire process up to firing by the carrier sheet and/or the covering sheet. During this time, the ceramic raw material sheet or semi-dry state is cut into any desired thin knife shape, and the part that will become the cutting edge is processed by cutting and polishing to form a thin knife shape, and the thin knife shape is made through a firing process. By holding the base sheet between the carrier sheet and the covering sheet, or supporting either one of them until the firing process, it is possible to manufacture thin cutlery without warping or distortion.

Next, examples of the present invention will be shown, but the present invention is not limited thereto.

Example The following five main raw materials were used in this example, with alumina and zirconia as the main raw materials.

(a) When alumina is the main raw material (unit, weight %) Alumina 90-99 to magnesia 10-1 (b) When zirconia is the main raw material (unit, weight %) Zirconia 80-99 to ittria 20 ~1 Calcia 20-1 for zirconia 80-99, Magnesia 20-1 for zirconia 80-99, Alumina 30-10 for zirconia 70-90. 20 to 40 parts of a mixture of trichloroethylene and ethanol, 0.1 to 3 parts of glycerin monooleate as a dispersant, 3 to 20 parts of ammonium acrylate or polyvinyl butyral as a binder, and polyethylene glycol and phthalate ester as plasticizers. 3 to 10 parts of the mixture were added, and the mixture was slowly stirred and mixed to the extent that no air was mixed in to form a base material for slurry. Next, the substrate surface was covered with a coating sheet while the substrate raw material was allowed to flow and adhere onto a 25 μm thick polyester carrier sheet to which bittern as a coagulant had been applied in advance. The sheet-shaped blade base sandwiched between the carrier sheet and the cover sheet has a thickness of 0.05 mm,
It was wrapped around a roller while being held in place. During firing, the blade base is sandwiched between the upper and lower sheets, cut to the size of the setter for firing, and stacked on the setter with alumina powder interposed between them.

In the experiment, 20 sheets were stacked on a setter, and the temperature was 1610℃ for alumina main material and 1100℃ for zirconia main material.
A sintered knife was obtained by firing at 1450°C. Note that since the alumina powder for preventing fusion was spread and fired, no fusion occurred on any of the sheets, and the alumina powder could be easily removed.

[Brief explanation of the drawing]

The drawings are for explaining the method of the present invention, and FIG. 1 shows the process of sandwiching the blade base between upper and lower sheets. 1: Carrier sheet, 2: Blade base, 3: Covering sheet.

Claims (1)

[Claims] 1. A kneaded product of ceramics using water as the main medium;
Alternatively, a ceramic cutlery base material made of mud is adhered to an organic carrier sheet in the form of a thin film, or after being attached, an organic coating sheet is coated on top of the cutlery base material while it is still undried. Then, the sheet-like base material is held between a carrier sheet and a covering sheet, and then the base material is cut into the shape of a knife, or without cutting, with or without removing either the carrier sheet or the covering sheet. A method for manufacturing thin-walled ceramic cutlery, characterized in that one or two or more sheets are stacked and fired, and the uncut fired base is cut into a knife shape to obtain a knife. 2. A method for manufacturing a thin ceramic cutlery according to claim 1, wherein the cutlery blank is held between a carrier sheet and a covering sheet, and then passed together between rollers to make the wall thickness uniform. 3. The method for manufacturing thin ceramic cutlery according to claim 1 or 2, wherein a coagulant is applied onto the carrier sheet to adhere the ceramic cutlery base material.