JPS6226488A - Dunnage material for baking - 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 A. Object of the Invention Industrial Application Field The present invention relates to an underlay material used when firing pottery such as ceramics and ceramics.

Conventional technology and its problems Conventionally, when firing pottery, molded products and shelf boards or molded products tend to stick together due to dripping of glaze, which is a major cause of defective products.

To solve this problem, methods such as spreading alumina or cordierite powder or applying or spreading alumina paste mixed with a small amount of clay have been used.
The method of spreading powder has disadvantages such as the powder scattering and damaging the appearance of the pottery, and cleaning after firing is troublesome.On the other hand, the method of applying alumina paste requires that it be applied thinly and evenly. There are disadvantages such as cracks in the coating layer and deformation of the pottery, which requires time and skill.

There is also a method of fixing molded ceramic products with triangular points and polishing only the contact areas, but this method also has the disadvantage of leaving traces of the triangular points and poor workability. That's what I'm doing.

Furthermore, a method was also used in which a utensil top or senbei (rice cracker) plate with a shrinkage rate similar to that of pottery was made in advance using pottery clay similar to that used for pottery, and then alumina or the like was coated on top of the plate to serve as an underlay material for pottery. However, it has the major drawback of being extremely time-consuming and inefficient.

The present invention aims to solve the above problems, and is an underlay material used when firing pottery.Even if glaze drips, it does not stick to the pottery and can be easily removed from the pottery after firing. This was achieved as a result of intensive research into creating a sheet-like product that is easy to use, inexpensive, and disposable.

Structure and operation of the invention The structure of the present invention is a sheet used as an underlay material when baking pottery, etc., the main components of which are heat-resistant inorganic powder, heat-resistant inorganic fiber, and clay mineral. The sheet has an initial tensile strength of 0.5 Kg/15 mm or more, an air permeability of 5 seconds/100 cc or more, and a folding strength of 10 to 500 after firing the sheet.
g150mm width and the shrinkage rate due to the firing process is 1
An underlay material for firing characterized by having a content of 0% or less.

The main points are as follows.

Means to solve the problem The main components of the sheet-like material are heat-resistant inorganic powder, heat-resistant inorganic fiber, and clay mineral, and these are processed into sheets with various physical properties using a wet paper-making method, and each is confirmed through experiments. As a result of searching for an appropriate physical property range, it was found that a sheet having the following physical property conditions was the most suitable.

First of all, the major requirement for this sheet is that the glaze does not penetrate at high temperatures.

This requires making the sheet denser and increasing its air permeability, and as a result of experiments, the air permeability was increased to 5 seconds/100cc.
They learned that by limiting the area to areas north of the area, it was possible to prevent the glaze from penetrating at high temperatures.

It goes without saying that if the air permeability is smaller than this value, the glaze will penetrate and the object of the present invention cannot be achieved, and the preferred value is 10 seconds/100 cc or more.

Next, as for strength, the initial strength of this sheet is high to a certain extent, and after firing, the strength is low enough that even if the sheet and the pottery stick together, it can be easily removed, and it can be broken into powder for easy cleaning. It is required to have sufficient strength to prevent damage.

Physical properties that meet this requirement include, as a result of experiments, that the initial tensile strength of this sheet is 0.5 kg or more for a width of 715 mm, and that the folding strength of the sheet after firing is 10 to 50.
It needs to be 0g and 150mm wide.

If the initial tensile strength is less than this value, the handling becomes difficult and it cannot be used. On the other hand, if the folding strength after firing is less than the lower limit above, it will break into pieces and become difficult to clean; If it exceeds 100%, it becomes difficult to remove when it adheres to the pottery, and the pottery itself is damaged. Desirable range of this folding strength
mm □ is 20 to 200 g and 150 mm width.

□ rilX"°°°°ゝ"'"S 364"-7)L'"
116”: (height 10m+a or more) to 50mm
Take out the 50mm x 50 that comes out from this stand □
This is the value obtained by placing a load on the center of the mm section and measuring the load when the sheet folds.

□ This folding strength is the value after firing, so the □
In the present invention, the measurement is performed at 1300'c.
□It was performed using treated materials.

□ In addition, this sheet is required to not curl, roll up, or wave when exposed to high temperatures, and does not adhere to the pottery.To do this, the sheet must have a small shrinkage rate during the baking process, and experiments As a result, the shrinkage rate is 10%
It was found that the following conditions were required. In other words, if the yield 178N of this sheet exceeds 10%, it will curl or wave during firing, and the sheet will turn over and adhere to the pottery.

The uninvented underlay material must satisfy the above conditions, but it must also have a low organic content, not melt or vitrify during firing and adhere to the shelf, and be smooth and flexible. This is what is required.

If this organic component is too large, carbide remains and causes negative effects, so it is desirable that the content of the organic component is 5% or less.

In addition, when removing the sheet after firing or when taking out the sheet with the baked goods still attached, it is required that the sheet does not adhere to the shelf board to the extent that this removal work is not hindered.
For this, the main materials are heated to 1300'C, the highest temperature normally used for firing.
Therefore, it is necessary to use a material that does not vitrify or melt.

Furthermore, it is desirable that the shrinkage rates of the sheet and the pottery are similar; even if the difference is large, the surface of the sheet should be smooth and easy to bend, and the sheet should be flexible enough not to interfere with the stable shrinkage of the pottery. appropriate smoothness and flexibility are required. This flexibility also brings about good results in the manufacture, storage, and transportation of the sheet, and also provides the effect that it will not bend or crack when placing pottery on it.

These problems, such as low organic content, high melting point or softening point, smoothness and flexibility, can be solved mainly by the constituent materials, and as a result of investigation, the following main materials were found. It was selected.

The main materials of the underlay material of the present invention are heat-resistant inorganic powder, heat-resistant inorganic fiber, and clay mineral, and these will be specifically explained below.

As a heat-resistant inorganic powder, the melting point or softening point is 1300
It is preferably 1500'C or more, preferably 1500'C or more, and has fire resistance such as alumina, silica, mullite, silicon carbide, zirconia, and zircon. However, if it contains low melting point substances such as sodium oxide, potassium oxide, boron oxide, etc., it will stick to the shelf board, so it is necessary to select a material that does not contain these substances.

The content of this inorganic powder is preferably 50 to 90%; if it is less than 50%, the pores will become large and the glaze will easily penetrate, while if the content exceeds 90%, the entire sheet will become brittle and easily break. This leads to major drawbacks in manufacturing, such as the droplets falling off during papermaking, resulting in poor yields, and attempts to prevent the droplets taking time to separate the water, and also making it difficult to handle in terms of strength.

In the present invention, as the heat-resistant material R male, those having a melting point or softening point of 1300''C or higher, preferably carbon alumina fiber 1. Alumina fiber, silicon carbide fiber, ceramic fiber, etc. can be suitably used. .

The content of this inorganic Nh miscellaneous material is desirably 5 to 45%; if it is less than 5%, the sheet becomes brittle and easily breaks, and shrinkage during firing becomes large, and manufacturing becomes difficult. On the other hand, if this content exceeds 45%, the porosity increases and the air permeability decreases, making it easier for the glaze to penetrate. Moreover, if this content is high, it is generally disadvantageous in terms of cost.

Clay minerals in the present invention include, for example, sepiolite, attapulgite, montmorillonite, swellable fluorinated mica, and those having film-forming ability upon dehydration are preferably used.

The content of this clay mineral is preferably 5 to 30%; if it is less than 5%, the strength will be low and it will be difficult to handle; on the other hand, if the content exceeds 30%, the four parts of the sheet At the same time, the fern sheet becomes brittle and its water resistance deteriorates, making it difficult to manufacture. Please note that if natural clay minerals containing impurities are used, they tend to stick to the shelf board, so care must be taken.

In addition, the underlay material of the present invention is heated to 800℃, which is the usual firing temperature.
Although it can be applied to temperatures up to L300'C, it is of course possible to design it to withstand firing temperatures of 1300'C or higher, such as when firing ceramics or lath, if necessary. It goes without saying that when using glaze, it may be used even if it is less than aooc.

In addition, the basis weight of the underlay material of the present invention is preferably 50 g/a or more in terms of tensile strength and air permeability, and 500 g/- or less in terms of flexibility and folding strength. be.

Example Alumina powder with a particle size of 5W was used as the heat-resistant inorganic powder,
Using ceramic fibers as the heat-resistant inorganic fibers and sepiolite as the clay mineral, underlay materials having three types of blending ratios as shown in Table 1 were prepared.

Table 1: In this case, 2 parts by weight of acrylic adhesive was mixed with these raw materials, a small amount of coagulant was added, and the paper was formed and dried using a box-shaped hand paper machine, each having a basis weight of 200 g/m. It was manufactured to be a sheet of '.

Test No. 1 is a comparative example in which the amount of ceramic fiber blended is too small, while Test No. 3 is a comparative example in which the amount of alumina powder is small.

In other words, test No. 2 is an example corresponding to the present invention.

The initial physical properties of these sheets were as shown in Table 2.

Table 2 Next, these sheets were fired at 1250'C for 3 hours, and their folding strength and shrinkage due to firing were measured, and the results shown in Table 3 were obtained.

Table 3 From these tables, it is determined that Test No. 011 cannot be used because the shrinkage rate is too high, and Test No. 013 is judged to have low air permeability and can easily pass through the glaze.

Actually place the above three types of sheets on the shelf board, □
Place a clay glaze on an unglazed plate on top, 125
When we conducted an experiment to perform firing at 0'c, test No. 1 was obtained.
When the shrinkage rate was too high, the edges were peeled off and stuck to the plate, severely damaging the appearance of the pottery.Not only did the sheet crack, but the glaze adhered to the seed plate in some areas.

In test No. 3, the glaze penetrated through the sheet to the shelf board, and the pottery and the shelf board were completely bonded.

However, the sheet of test No. 2 that was used as an underlay material slightly adhered to the pottery, but did not stick to the shelf board, and the entire sheet could be easily taken out from the shelf board, and the sheet attached to the pottery was removed. After removing the damaged part and polishing it with sandpaper, I was able to finish it very nicely.

C. Effects of the Invention (H) As explained in detail, the present invention is a sheet containing LIW thermal inorganic powder, heat-resistant inorganic fiber, and clay mineral as main components, which has a small amount of organic components and has moderate density. This is an underlay material for firing that is made so that the glaze does not penetrate through it, has a somewhat high initial tensile strength, and has a bending strength after firing that is limited to a predetermined range.

Therefore, even if glaze drips onto this underlay material, it will not stick to the seed plate, and even if it does stick to the pottery, it can be easily removed, and since it breaks into pieces of a certain size rather than powder, it is very easy to clean. It becomes easier.

In addition, the underlay material of the present invention has a low shrinkage rate and does not curl or wave during firing, so it does not have a negative effect on the pottery.It also has excellent smoothness and flexibility, and the sheet itself is easy to handle. Because it has cushioning properties when placing pottery on it, it does not bend or crack, and does not prevent the pottery from shrinking.

As described above, the underlayment material of the present invention improves the conventional method of firing pottery, exhibits simple and efficient workability, and is extremely effective in obtaining stable quality of pottery products.

Claims (1)

[Scope of Claims] 1. A sheet used as an underlay material when baking pottery, etc., the main components of which are heat-resistant inorganic powder, heat-resistant inorganic fiber, and clay mineral, and whose initial tensile strength is is 0.5Kg/15mm width or more and its air permeability is 5
sec/100 cc or more, the sheet has a folding strength of 10 to 500 g/50 mm width after firing treatment, and has a shrinkage rate of 10% or less due to the firing treatment. 2. The firing according to claim 1, wherein the content of heat-resistant inorganic powder is 50 to 90%, the content of heat-resistant inorganic fiber is 5 to 45%, and the content of clay mineral is 5 to 30%. Underlay material.