JPH02275743A - Heat-resistant potassium titanate fiber-containing sheet, production and use thereof - Google Patents

Abstract

PURPOSE:To obtain the subject sheet having excellent heat resistance, durability, etc., by dispersing a mixture of ZrO2, SiO2 and sodium aluminate into a concentrated aqueous solution of sodium silicate to give a mixture of inorganic dispersed material base and dispersing potassium titanate fibers into the mixture of inorganic dispersed material base. CONSTITUTION:A solution of sodium silicate dissolved in a small amount of water is blended with an inorganic mixture to give a dispersed material and 2 to 15wt.% based on the dispersed material of potassium titanate fibers are dispersed into the dispersed material to give a dispersed substance. Then a proper amount of the dispersed substance is poured onto filter paper on a suction filter, most of water is removed by suction filtration, the resulting material is dried at room temperature-90 deg.C for about 1 hour and further cured at 130 to 350 deg.C for about 1 hour. In the operation, thickness of dried sheet prepared by pouring of one time is about 500mum. Further the prepared potassium titanate fiber-containing sheet has extremely excellent wear resistance and heat shock resistance besides the abovementioned characteristics, the clearly more excellent abovementioned characteristics when used as a mold for casting than conventional mold and further excellent mold release properties.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention provides heat-resistant potassium titanate fiber-containing sheets,
The present invention relates to a method for manufacturing the same and the use of the sheet as an inner coating for a casting mold.

The casting mold manufactured in this manner has excellent thermal shock resistance, mold releasability, durability, and abrasion resistance.

[Problem to be solved by the prior art and the invention 1 Casting molds are coated with a commercially available soft molding agent (
It is used while making a mold with a ceramic kneaded into water glass. However, the final number of shots for copper alloy casting molds is limited to several thousand shots. This is because distortion or wear occurs on the surface of the mold body.

However, in such a mold, the temperature at the time of casting is 1250
If a coating that can withstand temperatures up to 1,300°C and has thermal shock resistance, mold releasability, durability, and abrasion resistance is developed, it can be attached to the inner surface of a mold to improve the durability, heat resistance, and heat resistance of the mold. In addition to improving mold releasability and abrasion resistance, there is no need for soft coating. However, such a sheet-like material has not conventionally existed.

In recent years, adhesives containing mainly inorganic components have been researched.

For example, Japanese Patent Publication No. 50-33491 discloses that a mixture consisting of finely divided high-purity zirconium oxide, colloidal silicic acid, and sodium aluminate in an amount of 2 to 10x of their total weight is calcined at 1000°C or higher and pulverized. A method for producing a highly heat resistant adhesive composition is disclosed. Adhesives produced by this method have a low curing temperature, and a curing time of 1 hour at 250-350°C is reported to be sufficient.

Furthermore, Inorganic Materials Research Institute Research Report No. 34, ``Research on the synthesis of potassium titanate fibers'', Science and Technology Agency, 198
2, 1-37, discloses potassium titanate fibers having excellent abrasion resistance.

However, conventionally, there has been no sheet-like product that combines the above-mentioned highly heat-resistant inorganic adhesive and potassium titanate fibers.

[Problem to be Solved by the Invention 1] An object of the present invention is to provide the cough mold with excellent heat resistance, durability, thermal shock resistance, and excellent heat resistance, durability, and thermal shock resistance. The objective is to develop a sheet that can be given abrasion resistance.

The inventor of the present invention has found that this problem can be solved as a result of intensive research.

[Object of the Invention 1 That is, the object of the present invention is to add 5% to an inorganic mixture in which a mixture of zirconium oxide, silica and sodium aluminate is dispersed in an aqueous sodium silicate solution to which a small amount of water has been added.
The present invention relates to a heat-resistant potassium titanate fiber-containing sheet formed of dispersed potassium titanate (Kz Ti60+3) fibers with a length of ~200 μm and a diameter of 0.05-5 μm.

Furthermore, the subject of the invention is: a) a length of 5 to 200 pm and 0.05 to 5 μm;
Potassium titanate (KzTi 6013) fibers with a diameter of The dispersion is poured onto a liquid permeable filter medium, especially a sheet filter medium, most of the water is filtered off from the dispersion, dried at a temperature between room temperature and 90°C, and the dispersion is poured and water removed. optionally repeated depending on the desired sheet thickness, and the resulting sheet-like filtrate is subjected to a curing reaction at 100-350°C after separation from the filter medium; or b) a length of 5-200 uI11. and potassium titanate (
lhTi, 0+3) fibers are dispersed in water and the dispersion is poured onto a liquid-permeable filter medium, in particular a sheet filter medium, of a filtration device, in particular a suction filtration device, to filter off most of the water from the dispersion. Then, an aqueous dispersion in which a mixture of zirconium oxide, silica, and sodium aluminate is dispersed in an aqueous sodium silicate solution containing a small amount of water is applied to the sheet-like filtrate obtained in this manner, and the mixture is heated at a temperature of from room temperature to 90°C. The sheet-like material thus obtained is dried under
The present invention relates to a method for producing the potassium titanate fiber-containing sheet, which is characterized by curing at 350°C.

Potassium titanate fibers that can be used in the present invention are described in the above-mentioned Inorganic Materials Research Institute Research Report No. 34. The role of this fiber is to provide heat resistance, durability, abrasion resistance and mold release properties to the sheet of the invention. This fiber is
Considering water dispersibility and sheet thickness, 5 to 200μ
m, in particular a length of 10 to 50 μm and 0.05 to 5 μm,
Particular preference is given to fine particles having a diameter of 0.1 to 1 μm. The amount of potassium titanate fibers added to the aqueous inorganic mixture dispersion is advantageously between 2 and 30% by weight. The potassium titanate fibers are advantageously dispersed in an aqueous dispersion of an inorganic mixture with a concentration of 30 to 952.

The water-soluble inorganic mixture used in the present invention consists of zirconium oxide, silica, and sodium aluminate, and 40 to 50 parts by weight of sodium silicate is used per 100 parts by weight of the total amount of these components. The inorganic mixture is 25 to 7
It has proven advantageous to have a composition consisting of 0% by weight of zirconium oxide, 25 to 65% by weight of silica and 2 to 8% by weight of sodium aluminate. A sheet produced using this mixture has a heat resistance of 1300° C. after curing.

The sodium silicate-containing aqueous dispersion of the inorganic mixture used in the present invention is air-dried or dried at a temperature of up to about 90° C. to avoid unevenness in the applied product due to rapid evaporation of water. Cure ring is 100-35
It can be carried out at about 0°C.

The thickness of the sheet of the present invention is not particularly critical, but for example, when attached to the inner surface of a casting mold,
Advantageously, it is on the order of μm.

However, thicker materials can be used for applications that do not require critical dimensional stability.

Two advantageous embodiments for producing the sheets of the invention are described below: First, the dispersion is prepared in a dispersion in which the inorganic mixture is incorporated into a sodium silicate solution dissolved in a small amount of water. Disperse potassium titanate in an amount of 2 to 15% by weight, pour an appropriate amount of this dispersion onto the filter paper of a suction filter, remove most of the water by suction filtration, and heat at a temperature from room temperature to 90"C. Dry for about 1 hour and heat at 130~350″C
Curing for about an hour.

The thickness of the dry sheet obtained by one pouring is 5
It is up to about 00 μm. To produce even thicker sheets, the above pouring and water removal operations are repeated, followed by a curing reaction.

In the second embodiment, potassium titanate fibers are dispersed in water, an appropriate amount of this dispersion is poured onto a filter paper of a suction filter, most of the water is removed, and a sheet is obtained. An appropriate amount of an aqueous dispersion of an inorganic mixture containing sodium silicate with a concentration of 30 to 95% by weight was sprayed onto the top, and after drying slightly at room temperature, the same aqueous dispersion was applied with a brush, and the mixture was heated at a temperature from room temperature to 90°C. Dry for about 130~3 hours
Cure at 50°C for about 1 hour.

According to this latter method, the sheet can be obtained in one step regardless of the desired thickness of the sheet.

The drying method using the absorption filtration device used in the above two embodiments is a natural filtration method on a sheet-like or very fine mesh filter material, a drying method by blowing dry air on the filter material, or It is also possible to replace the water removal method with rolls.

However, it is more efficient to forcibly remove water by suction filtration.

The sheets thus obtained have excellent heat resistance, durability, thermal shock resistance and abrasion resistance, and are suitable for use with specific adhesives in instruments, equipment and machinery requiring such properties. Give them the above properties by pasting them. The particular adhesive used for this bonding is a mixture of zirconium oxide and silica as major components and sodium aluminate as a minor component, dispersed in a sodium silicate solution containing a small amount of water, especially 50% A mixture consisting of ~70% by weight zirconium oxide, 25-35% by weight silica and the balance sodium aluminate is dispersed in 40-50 parts by weight of sodium silicate containing a small amount of water per 100 parts by weight of the mixture. This is what I did. This adhesive has a heat resistance of 1300° C. after curing.

The present invention also relates to a casting mold in which the sheet described above is bonded to the inner surface of the mold using the adhesive described above. The inner surfaces of the mold to which the sheet is attached are those of the mold sprue, riser, riser, and mold body.

Furthermore, the present invention applies the above-mentioned sodium silicate-containing aqueous inorganic adhesive containing zirconium oxide and silica as major components and a minor component of sodium aluminate to the sheet of the present invention, and attaches this to the inner surface of a mold and allows the adhesive to be heated at room temperature. The present invention relates to a method for manufacturing a mold, which comprises curing at 100 to 350°C after drying at 90°C.

This mold coated with a sheet containing potassium titanate fibers not only has sufficient heat resistance required for casting, but also has excellent wear resistance and is easy to remove when removing the molded product from the mold after casting. It also has excellent mold release properties. Furthermore, 1 without using a soft coating type.
Even when molding is performed for 0,000 squeezes, no abnormality occurs in the surface condition of the molded product, and it has excellent durability that can be used satisfactorily.

The invention will be explained in more detail below using examples: Implementation n (Preparation of sheets) 29.6% by weight of zirconium oxide, 58.0% by weight of silica and 2.4% by weight of sodium aluminate An aqueous solution of JIS No. 2 sodium silicate (22 g) with 5'd of water added to 50 g of the solvent was added and kneaded until it became a viscous paste, and this was dispersed in 40 g of water. 10 g of potassium titanate fibers having an average length of 20 μm and an average diameter of 0.9 μm are dispersed in this dispersion. Inner diameter 100m
Place a filter paper on a Nutsche (m), pour this dispersion onto it, and remove most of the water by suction filtration. A sheet having a wet thickness of approximately 1+m++ is obtained. Remove this along with the filter paper and place on a fresh filter paper to air dry for 1 hour at room temperature. It is then cured for 1 hour at a curing temperature of 150° C. in a drying room. The sheet obtained has a thickness of approximately 0.6 m.

1b - 50 g of an adhesive consisting of 64.0% by weight of zirconium oxide, 31.2% by weight of silica and 4.8% by weight of sodium aluminate were added with 5d of water J
Add an aqueous solution of IS No. 2 sodium silicate (22 g) and knead until it becomes a viscous paste. Using this dispersion, the sheet produced according to Example 1a was molded into a copper alloy mold for the casing of an automobile engine (this mold is described in detail in Japanese Patent Application No. 63-306824; Ni plating layer on the inner surface, C as an intermediate layer
o/Mo/Cr-alloy coating layer and outer layer (D A
lzo:I/Zr03-A copper mold having three layers in the order of porous ceramic coating layer), the inner surface of the sprue, etc. After leaving to dry at room temperature for 1 hour,
Cure in a drying room at a temperature of 0°C.

The above mold thus manufactured was heated to 350 to 4°OoC.
When the molded product was used to cast a casing for an automobile engine while being cooled to a temperature of 10,000 shots, there was still no change in the surface and the surface condition of the molded product was good.

Demoulding is very easy.

Potassium titanate fibers Log having an average length of 20 μm and an average diameter of 0.9 μm are dispersed in 50 ml of water.

Next, this dispersion is poured onto a Nutsche with a filter paper having an inner diameter of 100 mm, and most of the water is removed by suction filtration. 65 on the resulting sheet-like material
．． JIS 2, in which 4 d of water was added to 50 g of an inorganic mixture consisting of 6 wt% zirconium oxide, 32.0 wt% silica, and 2.4 Hz sodium aluminate.
Kneading solution 10 prepared by adding and kneading 23 g of sodium silicate
The nTl is sprayed and left at room temperature for about 10 minutes, after which the remaining dispersion is applied to the sheet by brush.

After application, dry at 90°C in a drying room for 30 minutes. After drying, cure at 150°C for 1 hour. Approximately 1mm
A sheet of thickness is obtained.

2b) The sheet obtained according to Example 2a is applied to a mold and cured exactly as in Example 1a.

When the above-mentioned mold manufactured in this way was used for casting a casing of an automobile engine while being cooled to 350 to 400°C, there was still no change in the surface even after io and ooo shots, and the surface condition of the molded product remained unchanged. was also good. Demoulding is very easy.

A casting test was conducted using a copper alloy mold to which a sheet containing potassium titanate fiber was not attached.

When 8,000 shots were performed while coating the mold with a commercially available mold coating agent (ceramic mixed with water glass) every 200 shots, the mold surface wore out and became unusable. .

[Effects of the Invention] The sheet of the present invention has extremely excellent mold release properties, heat resistance, abrasion resistance, durability, and thermal shock resistance, and when used in casting molds, it is superior to conventional sheets. Compared to molds, it has clearly superior heat resistance, abrasion resistance, and durability, and also has superior mold release properties, which eliminates the hassle of painting molds, making it a remarkable contribution to industry. It is something.

Claims (1)

[Claims] 1) A dispersion in which a mixture of zirconium oxide, silica and sodium aluminate is dispersed in an aqueous sodium silicate solution to which a small amount of water has been added.
A heat-resistant potassium titanate fiber-containing sheet formed from a dispersion of potassium titanate (K_2Ti_6O_1_3) fibers having a length of 0.05 to 5 μm and a diameter of 0.05 to 5 μm. 2) In producing the heat-resistant potassium titanate fiber-containing sheet according to claim 1, potassium titanate (K
_2Ti_6O_1_3) The fiber is made of zirconium oxide,
A mixture of silica and sodium aluminate is dispersed in an aqueous sodium silicate solution to which a small amount of water has been added, and this dispersion is poured onto a liquid-permeable sheet filter of a suction filtration device, and a large amount of water is removed from the dispersion. The portions are filtered off and dried at temperatures ranging from room temperature to 90° C., and such dispersion pouring and water removal processes are optionally repeated depending on the desired sheet thickness, so that the resulting The above method for producing a potassium titanate fiber-containing sheet, which comprises separating the sheet-like filtrate from the filter medium and then subjecting it to a curing reaction at 100 to 350°C. 3) In producing the heat-resistant potassium titanate fiber-containing sheet according to claim 1, potassium titanate (K
_2Ti_6O_1_3) Disperse the fibers in water, pour this dispersion onto a liquid-permeable sheet-like filter medium of a suction filtration device, filter off most of the water from the dispersion, and thereby obtain a sheet-like filter. spraying and applying an aqueous dispersion of a mixture of zirconium oxide, silica and sodium aluminate in an aqueous sodium silicate solution to which a small amount of water has been added, drying at a temperature between room temperature and 90°C; The above-mentioned method for producing a potassium titanate fiber-containing sheet, which comprises curing the sheet-like product thus obtained at 100 to 350°C. 4) The heat-resistant potassium titanate fiber-containing sheet according to claim 1 is dispersed in a sodium silicate aqueous solution to which a mixture containing zirconium oxide and silica as main components and sodium aluminate as a minor component is added with a small amount of water. A casting mold that is bonded to the inner surface of the mold using a water-based inorganic adhesive that is a dispersion. 5) In manufacturing the casting mold according to claim 4, a mixture containing zirconium oxide and silica as main components and sodium aluminate as a minor component is added to the sheet according to claim 1 with a small amount of water. The process is characterized by applying an aqueous inorganic adhesive, which is a dispersion in an aqueous sodium silicate solution, pasting this on the inner surface of the mold, drying at room temperature to 90°C, and then curing at 100 to 350°C. , a method for manufacturing the above-mentioned casting mold.