JP6709489B2 - Clay burning building materials - Google Patents

Description

The present invention relates to clay-fired building materials such as clay roof tiles, clay tiles, and clay bricks, and more particularly to clay roof tiles.

Clay-fired building materials such as clay roof tiles are produced by firing molded and dried clay-based raw materials, so weather resistance, fire resistance, waterproofness, heat insulation, sound insulation, corrosion resistance, aesthetics, etc. In many respects, it has advantages over other building materials. However, such a clay-fired building material is required to have a certain thickness in order to secure sufficient mechanical strength, and there is a problem that the weight becomes very large. Therefore, in order to meet requirements such as easy transportation and construction of clay-fired building materials, and weight reduction of buildings, there is a strong demand for clay-fired building materials that are lightweight while maintaining strength.

Various attempts have been made to date as such lightweight clay-fired building materials.

For example, in Patent Documents 1 and 2 and the like, the flat portion of the roof tile is thinned to reduce the weight, but in order to reduce the strength associated therewith, a reinforcing rib is provided on the back side of the roof tile. It compensates for the decrease in strength. Similarly, in Patent Document 3, the strength is improved by making the center portion, which is easily broken, thick.

Further, in Patent Documents 4 and 5, etc., the weight is reduced by firing a hollow porous body using a clay material to which a porous forming material or the like is added. Further, in Patent Document 6, by adding a pulverized product of a thermosetting resin molded product to a raw material for ceramics and firing it, both weight reduction and strength are achieved.

Further, in Patent Document 7, it has been stated that by making three flat roof tiles vertically connected to each other as an integrated roof tile, it is possible to eliminate an overlapping portion when performing construction, thereby reducing the weight.

JP, 10-325215, A Japanese Patent Laid-Open No. 05-230937 JP, 2007-224540, A JP, 2009-179548, A JP, 2007-210872, A JP, 2003-342057, A JP2012-202153A

Etsuro Kato et al., “Effect of Glazing on Bending Strength of High-Strength Magnetic Substrate,” Journal of Ceramic Society of Japan, 98[5]504-09 (1990). Toshihiko Akizuki et al., "Development Research on Reinforced Porcelain (1) Development on Reinforced Porcelain Ceramics", Nagasaki Prefectural Ceramic Technology Center Research Report (2000), pp. 43-48 Tile roof standard design/construction guidelines, pages 23 to 25 (Fig. II-1-1 and Fig. II-1-2), supervised by: Institute of Building Research, published by: Federation of All Japan Tiled Works, National Ceramics Federation of tile industry association, National Federation of Thick Slate Association, published on August 13, 2001, edited by tile roof standard construction guidelines committee))

Although various attempts have been made as described above, these known methods cannot always be easily dealt with only by using existing equipment.

Therefore, there is still a long-felt demand for a technique that can deal with the existing facilities by making a slight change, and still effectively achieve both weight reduction and strength of the clay-fired building material.

The present inventors, in a clay-fired building material having a gutter-shaped concave curved shape in the thickness direction from the front side to the back side, on the back side of the building material, along the valley bottom line of the concave curved shape, and the valley bottom. By forming the back side glaze layer as a substantially strip-shaped glaze area including a line, a study was conducted to improve the bending fracture strength of the roof tile (bending test of JIS A 5208 J-shaped and S-shaped crosspieces).

As a result, surprisingly, when the protruding partial structure is formed on the front side so as to cross the linear portion on the front side facing the end of the valley bottom line on the back side, the back side glaze is formed. Bending fracture of the building material, as compared with the case where the layer is formed so as to finish until reaching the back side surface region facing the raised partial structure, so as to cover even the back side surface region. It was revealed that the strength was significantly high (first aspect of the present invention).

Furthermore, as a more preferable aspect of the first aspect of the present invention, in a certain range of the width of the back side glaze layer, the bending fracture strength is more than in the case where the glaze layer is formed over substantially the entire width of the back side surface. It was also found to be good (second aspect of the present invention).
More precisely, the respective aspects of the present invention are as follows.

(First embodiment of the present invention)
That is, the first aspect of the present invention is a clay-fired building material having a thickness that is a front surface, a back surface, and a distance between the two surfaces, wherein the clay-fired building material is from the front surface to the back surface. Has a trough-shaped concave curved shape, which is curved concavely in the thickness direction toward
On the back side surface, along the valley bottom line of the concave curved shape, and the back side glaze layer is formed as a substantially strip-shaped region including the valley bottom line,
The valley bottom line refers to a linear portion that passes through the lowest portion of the trough-like concave curved shape when the clay-fired building material is temporarily placed on a horizontal surface,
The clay-fired building material is further
It has a protruding partial structure so as to cross a linear portion on the front side surface facing at least one end of the valley bottom line on the back side surface, and the back side glaze layer faces the protruding partial structure. It is finished by the time it reaches the back side area,
Here, the end portion of the valley bottom line refers to a linear portion extending from one end of the valley bottom line to the other end, and the length in the valley bottom line direction is 24% or less of the total length of the valley bottom line. It is a clay-fired building material characterized by the above.

(Second aspect of the present invention)
In the first aspect of the present invention, when the back side glaze layer is divided into two glazed partial regions by the valley line, each width of each of the two glazed partial regions is equal to that of the clay-fired building material. It is in the range of 15 to 30% of the total width of the back side surface, and the total width of the back side surface is the maximum width in the direction perpendicular to the valley bottom line on the back side surface of the clay-fired building material. It is a clay-fired building material.

The clay-fired building material of the present invention can improve the strength of the clay-fired building material by a simple means of forming a backside glaze layer in a specific region on the backside, and as a result, the thickness of the clay-fired building material can be reduced. By doing so, even if the weight is reduced, sufficient strength can be maintained.

From the viewpoint of manufacturing cost, it is advantageous because only the back side glaze process is added to the existing equipment.

It is a figure which shows the shape of various clay roof tiles which can become the object of this invention (Source: Non-patent literature 3, 25 page-extract from Figure II-1-2). It is a figure explaining the name of each site|part of the J-shaped roof tile which is a typical object of this invention (Source: Nonpatent literature 3, page 23 FIG. II-1-1 excerpt). FIG. 5 is a plan view and a lateral view of the back side surface of the J-shaped slab for showing an example of the approximate positional relationship between the valley bottom line and the back side glaze layer. Each of the strip-shaped regions (a), (b), and (c) in the drawing shows a portion overlapping with an adjacent roof tile when the roof tile is installed, but the back side surface of the (a) portion is also usually glazed. In many cases, at least a part of the back side surface of part (b) is also glazed. However, in the following description of the invention of the present application, the glazed state on the back side of these (a) and (b) is not particularly mentioned. It is the photograph which observed the J-shaped sash from the back side after a bending test. It is glazed in a strip shape with a total width of 12 cm on the back side of the J-shaped roof tile. In the photograph, the upper part is placed on the hip side and the lower part is placed on the head side. It is sectional drawing (cut along a valley bottom line) of a building material part which shows the relationship (a1)-(a3) of various front side surface ridge partial structures and back side glaze layer of the building material in this invention. 9 is a schematic plan view showing the arrangement of holes formed on the back side surface of the J-shaped roof tile used in Test Example 4. FIG.

[1] Object of the present invention (1-1)
The present invention is directed to a clay-fired building material having a trough-like concave curved shape that is concavely curved in the thickness direction from the front side surface to the back side surface.

Here, the "trough-shaped concave curved shape" refers to a concave curved shape that can be likened to a groove-shaped trough having a U-shaped cross section, and is arranged linearly on the front surface of the clay-fired building material. It means a concave curved shape.

Typical objects of the present invention include J-shaped roof tiles, S-shaped roof tiles, J-shaped roof tiles, and J-shaped sleeve roof tiles (see FIG. 1).

(1-2)
In the clay-fired building material having the "trough-shaped concave curved shape", the concept of the valley line is introduced on the back side surface for convenience of description.

The valley bottom line here means a linear portion that passes through the lowest portion of the trough-like concave curved shape when the clay-fired building material of this embodiment is placed on a horizontal plane. Since stress is applied from the installation surface to at least a part of such a valley line, it is considered that cracks are likely to occur along the valley line.

More specifically, for each of the two-dimensional concave curves formed by the "trough-shaped concave curved shape" extending in the linear direction on a pair of opposing sides of the clay-fired building material, the clay-fired building material is It can be defined as a straight line on the back side connecting the lowest points when installed on a horizontal plane.

In a typical object such as an S-shaped or J-shaped roof tile, etc., the valley bottom line is usually arranged substantially vertically on a pair of opposite sides of the building material, but this is not necessarily the case, and it may be slightly displaced from the vertical. Good.

In addition, the bottom surface of the clay-fired building material is usually divided into two areas having approximately the same surface area by the valley line. More specifically, it is preferably divided into two regions having an area ratio of about 40:60 to 60:40.

Taking the S-shaped to J-shaped roof tiles, which are typical examples of this embodiment, as an example, a line obtained by extending a linear portion formed by direct contact between these roof tiles and the roof tile slab over one roof tile is the valley bottom. Almost corresponds to the line.

Usually, the S-shaped or J-shaped roof tile has a pair of hooking claws on the bottom of the back side, and the roofing tiles are placed by hooking the roof tiles on the upper surface of the roof tile bridge by the hooking claws. Therefore, it is considered that the valley bottom line normally passes through either of the pair of hooking claws (see FIG. 3 ).

Further, the J-shaped roof tile is usually provided with a stabilizing piece on the bottom of the back side, and when the roof tile is hooked on the upper surface of the roof tile, the stabilizing piece serves as a support to stabilize the roof tile so that it does not wobble. Therefore, it is possible to easily identify the linear portion formed by the roof tile coming into contact with the roof tile splint.

However, if there is no such stable piece, it may be difficult to uniquely determine the valley bottom line due to the wobble of the roof tile. Even in such a case, when the originally intended installation position is clear by the hooking claw or the like, the valley bottom line can be determined on the basis of this. However, if it is absolutely unclear, a linear portion that connects the midpoints of the areas swept by the linear portion formed by the roof tile wobbling contacting the roof tile stake may be used as the valley bottom line.

Table 1 below shows the positional relationship between the position of the valley bottom line and the hooking claws of various commercially available J-shaped roof tiles. According to this, the valley bottom line passes through a portion near the middle point of the two hooking claws on the rear side of the back of the J-shaped roof tile, but more strictly speaking, rather than the middle point of the two hooking claws, the water repelling is slightly It can be seen that it passes through a part that is closer to the side or slightly depending on the side opposite to the pier side.

In addition, the length referred to in the following table means the length projected on the horizontal plane when the roof tile is temporarily placed on the horizontal plane.

*1: Roof shape classification 53B
Length A: 295 mm, width B: 315 mm;
Working length a: 225 mm, working width b: 275 mm
Note that the five types of Sekishu roof tiles in the table have different manufacturers.
*2: Roof tile shape classification 53A
Length A: 305 mm, width B: 305 mm;
Working length a: 235 mm, working width b: 265 mm
The five types of Sanshu roof tiles in the table are from different manufacturers.
*3: Working size (working length, working width) refers to the effective size of the roof tile, taking into consideration that the effective size becomes smaller due to overlapping when roofing and roofing, etc. is there.

(1-3)
The clay-fired building material to which the present invention is applied is not flat because it has a trough-like concave curved shape. Therefore, when the length or area of the object of the present invention is a problem (for example, the length in the valley bottom line direction, the total length of the valley bottom line, the width in the direction perpendicular to the valley bottom line, the surface area of the glazed part area, the back side surface) When the clay firing building material is placed on a horizontal plane, the length and area can be estimated as values on a plane vertically projected on the horizontal plane.

[2] Clay-fired building materials The clay-fired building materials referred to in the present invention include clay tiles, clay tiles, clay bricks, etc. produced by a production process including a step of firing clay at a high temperature of about 1000 to 1250°C. A building material, typically a clay tile.

These clay-fired building materials are generally formed by molding clay extruded from a clay kneader into a metal mold and pressing it to form a building material, and then drying the formed building material. It is manufactured through a drying process and a firing process that fires the glazed building material, and as an optional step, a glaze (“front side glaze layer”) is provided on the front side of the dried building material between the drying process and the firing process. You may include the glaze process to apply.

The present invention is characterized in that the back side glaze layer is formed substantially in a band shape in a specific partial region of the back side of the dried building material. This step can be performed between the drying step and the firing step, but it is costly because it only requires the addition of the back side glaze step to the existing equipment used for forming the front side glaze layer. But it is advantageous.

Here, the front side surface refers to a surface to be placed on the outer side when a plate-shaped building material is installed, and the back side surface refers to a surface opposite to the front side surface.

Further, in the present invention, since the bending fracture strength of the clay-fired building material can be improved by the glaze treatment of the specific partial region on the back surface, the weight of the clay-fired clay can be reduced by reducing the thickness while maintaining sufficient strength. We can provide building materials. The thickness of the clay-fired building material that can be provided by the present invention is preferably 12 mm to 16 mm, and it is also possible to provide a lightweight product having a thickness of 6 mm to 12 mm.

The bending fracture strength referred to here is measured by three-point bending fracture load measurement on a steel plate, and is used for bending tests of J-shaped and S-shaped slabs (test slabs) specified in JIS A 5208. It is measured according to. However, according to JIS A 5208, the center round steel bar for load application (diameter: 30 mm) is arranged so that its central axis is as close as possible to the valley bottom line. Further, the two supporting steel round bars (30 mm in diameter) respectively arranged on the left and right lower sides of the test piece ridge are arranged so as to be parallel to the supporting steel round bars (in the case of the ridge, two bars are used). The distance between the supporting steel round bars is 200 mm). At this time, since each supporting steel round bar is closely attached to the test piece ridge and supports the test piece ridge substantially horizontally, if there is a gap and it is not stable, a gap is created between the supporting steel round bar and the ridge. A suitable rubber plate may be inserted.

If the length of the long side of the test piece is 200 mm or less, and the size of the test piece is relatively small, and it is difficult to set the distance between the two supporting steel round bars to 200 mm, 2 The interval between the two supporting steel round bars may be an interval corresponding to 83% of the long side length of the circumscribed rectangle of the test body.

Further, in the present invention, the weight per unit area can be 3.52 to 2.58 g/cm ^2, and further, a lighter clay-fired building material of 2.58 to 1.30 g/cm ² is provided. Is also possible. In addition, the weight per unit area referred to here is the two-dimensional plane of the clay-fired building material that is placed vertically on the horizontal plane when the clay-fired building material is placed on the flat horizontal surface in a state that it should be originally installed. The area of the shape is calculated based on the total area.

However, in the case of the J-shaped or S-shaped roof tile that can be the subject of the present invention, more simply, as a rectangular area having a length A and a width B of the roof tile of various size categories defined in JIS A 5280 Table 2 , It is possible to obtain the total area which is a standard for calculating the weight per unit area.

[3] About back side glaze layer (3-1)
In the present invention, the back side glaze layer is formed on the back surface of the clay-fired building material along the trough bottom line of the gutter-shaped concave curved shape and as a substantially strip-shaped glaze region including the trough bottom line.

As the glaze to be used, any known glaze can be used, but a glaze having a composition containing at least silicon and aluminum, more specifically, mainly SiO ₂ : 37%, Al ₂ O ₃ : 9% , A MnO:23%, Fe ₂ O ₃ :7%, CaO:6% composition is preferable from the viewpoint of melting and solidification.

(3-2) 1st aspect of this invention In the 1st aspect of this invention, it crosses the linear part on the front side surface which opposes at least one end part of the valley bottom line on the back side surface of a clay-fired building material. And a back side glaze layer is formed by reaching the back side surface region facing the rising part structure.

Surprisingly, the end of the back glaze layer ends by the time it reaches the back side region facing the raised substructure, more preferably it ends more immediately before the back side region facing the raised substructure. It was found that this has an advantageous effect on the bending fracture strength of the building material (see Test Example 1).

Here, the "end of the valley bottom line" means a linear shape extending from one end of the valley bottom line to the other end, and the length in the valley bottom line direction is 24% or less of the total length of the valley bottom line. Refers to the part. However, from the viewpoint of further securing the length of the back side glaze layer in the valley bottom line direction, the length in the valley bottom line direction is 15% or less of the total length of the valley bottom line, and therefore, "protruding partial structure". It is preferable to cross the linear portion of the front side surface facing the valley bottom line at a position closer to the side of the clay-fired building material.

The protruding partial structure usually crosses a linear portion on the front side facing one end of both ends of the valley bottom line on the back side of the building material, but the other end of the valley bottom line is further crossed. It is also possible to traverse a linear portion on the front side surface facing to. In this case, the protruding partial structures that traverse the linear portions on the front side surface facing both ends may be separate partial structures or continuous partial structures. In this way, when there is a partial structure that bulges at both ends of the valley bottom line, in the present invention, for at least one of the partial structures that bulge, the end condition of the back side glaze layer (“the back side glaze layer is raised. It is necessary to satisfy "the end until reaching the back side region opposite to the partial structure", but it is more preferable to satisfy the above-mentioned end condition of the back side glaze layer for both the raised partial structures.

Further, "crossing" includes not only the case where the protruding partial structure completely crosses the linear portion on the front side surface facing the valley bottom line end, but the protruding partial structure exists on the linear portion. As long as there is a break in the linear portion.

In addition, "the linear part on the front side facing the valley bottom line end" means that when the clay-fired building material is installed on the horizontal plane, the linear part on the front side is perpendicular to this horizontal plane. It means a linear portion on the front side surface such that the linear portion on the back side surface that passes when projected matches the above-mentioned valley bottom line end portion.

Furthermore, the "back side surface area facing the raised partial structure" means that when the clay-fired building material is installed on a horizontal plane, it passes when the raised partial structure on the front side is projected vertically on this horizontal plane. Refers to the back surface area.

Hereinafter, when the word "opposite" is used, it may be understood to have the same meaning as these.

(3-2-1)
The raised partial structure includes any partial structure that increases the thickness of the clay-fired building material, but more specifically, a water return wall for preventing rainwater from flowing down from the front side surface to the back side surface of the building material, A water return step wall (see Test Example 1) can be exemplified.

These raised structures are usually formed along the sides of the building material (thus, approximately perpendicularly or at an angle close to that which crosses the linear portion of the front side facing the valley bottom line ends), but with some misalignment. It may have been done.

More specifically, in the J-shaped roof tile used in Test Example 1, in order to prevent rainwater from flowing from the front side surface to the back side surface, a raised partial structure [three-step difference] is formed in the area near the tail side of the roof tile. (Each height is about 1 mm)], and the thickness increases to 2 mm on the butt side in the linear portion of the front side surface corresponding to the valley bottom line [see FIG. 5(a2)].

Then, in this test example, by taking various non-glazing widths from the bottom side of the J-shaped roof tile, back side glaze layers of various lengths are formed along the valley bottom line, and the bending fracture strength of each building material ( (Measured according to the bending test of J-shaped and S-shaped roof tiles defined in JIS A 5208). As a result, compared to the case where the back side glaze layer is formed to include the back side surface region facing the raised partial structure, the back side surface region facing the raised partial structure is not reached, that is, the back side glaze layer is facing. The bending fracture strength was significantly higher when the back glaze layer was formed so as not to include the back side region. This is a result contrary to the expectation that the strength will be improved simply by increasing the glazed area.

Further, even in the back side glaze layer not including the back side surface region facing the raised portion structure, the bending strength tended to be improved when glazed to a position close to the back side surface region facing the raised portion structure. ..

This is considered to be related to the uniformity of strength in the linear portion on the valley bottom line that is loaded in the bending fracture test. That is, when the raised partial structure crosses a linear portion on the front surface facing the end of the valley bottom line, the strength of the linear portion on the valley bottom line increases at the raised portion and the strength becomes unsatisfactory due to the increase in thickness due to the protrusion. It is uniform. However, by forming the back side glaze layer in a range that does not cover the back side surface region facing the raised portion structure, the strength non-uniformity of the glaze layer acts to eliminate the unevenness of the strength. This tendency is further enhanced by forming the back side glaze layer close to the raised structure. However, if the back side glaze layer covers even the back side surface region facing the raised portion structure, it cannot be expected to eliminate such nonuniformity. This is because both the raised partial structure portion and the non-raised partial structure portion receive similar strength improvement due to the back side glaze layer.

(3-2-2)
In addition, the "raised partial structure" includes those that can be visually confirmed as a bulge, but from the perspective of accommodating a sudden change in the thickness of building materials that may affect the bending fracture strength, In the above, there can be exemplified a structure in which the line connecting the ridge start point and the ridge maximum point makes a sharp ridge so that the angle formed with the valley bottom line is at least 45°. Here, the protrusion maximum point refers to a point at which the protrusion height first reaches a maximum when it moves from the protrusion start point in the direction of the protrusion along the valley bottom line. Typically, the thickness D of the clay-fired building material is a ridge having a height of about 0.05D to 0.2D (typically, a height of about 1 to 3 mm). A plurality of bumps may be gathered to form a step structure.

The thickness D of the clay-fired building material here can be represented by the thickness at the center point of the back side valley-bottom line of the clay-fired building material (point on the valley bottom line at half the length of the valley bottom line) in principle. .. However, if an accessory structure is formed at the center point and it is raised or depressed, the accessory structure will be lost if you start from the center point of the valley line and move in each direction along the valley line. The number of points (two points in total) may be averaged. The same applies to the thickness D of the clay-fired building material of the present embodiment that appears below.

Further, the “raised partial structure” may be formed up to the side of the roof tile (the side of the raised partial structure) [for example, FIG. 5(a1)], but even up to the side of the roof tile as shown in FIG. 5(a3). It may be one that has not reached. However, in any case, the "protruding partial structure" is at least 8.5% of the total length of the valley bottom line, more preferably 9% in the direction of the valley bottom line counting from one end of the valley bottom line (the side of the protruding substructure). %, more preferably 9.5%, and even more preferably 10% or more, at least a part of the partial structure thereof is preferably present.

Further, the length of the "protruding partial structure" in the valley bottom line direction can be arbitrarily determined within 24% of the total length of the valley bottom line, but may be 3% to 24% of the total length of the valley bottom line. it can.

Furthermore, “finishing before reaching the back side surface region facing the raised partial structure” means that the back side glaze layer does not cover the back side surface region facing the raised partial structure. Therefore, when the length in the direction perpendicular to the valley bottom line on the front surface of the raised partial structure is relatively short and narrower than the width in the direction perpendicular to the valley bottom line of the back side glaze layer, the back side glaze layer is, for example, , A mode in which the back side surface region facing the raised partial structure is glazed so as to surround the periphery, and the like.

(3-3) Second Aspect of the Present Invention A second aspect of the present invention is a more preferable aspect of the first aspect of the present invention.

That is, in the second aspect of the present invention, in the first aspect of the present invention, the width of the specific range of the back side glaze layer (width on the back side of the building material and in the direction perpendicular to the valley bottom line) is further defined.

That is, in the first aspect of the present invention, when the back side glaze layer is divided into two glazed partial areas by a valley line, the width of each of the two glazed partial areas is the back side of the clay-fired building material. Within the range of 15% to 30% of the total width of the surface.

This is preferable from the viewpoint of bending fracture strength (Test Example 2). Contrary to the simple expectation that the more glazed it is, the stronger the strength will be, but this is not bound by theory, but the position of the interface between the glazed part and the non-glazed part disperses the stress more due to the deformation near the interface. It is inferred that it is because it is in a position where it is easy to do.

In particular, from the viewpoint of improving bending strength, it is preferable that the two glazed partial regions are symmetrically arranged with the valley bottom line as the axis of symmetry (see Test Example 5).

Here, the width of each of the two glazed partial regions can be obtained as an average width obtained by dividing the area of each glazed partial region by the length of the glazed partial region in the direction of the valley bottom line.

Further, the total width of the back side surface of the clay-fired building material refers to the maximum width on the back side surface of the clay-fired building material in the direction perpendicular to the valley bottom line. For typical roof tiles such as J-shaped roof tiles, S-shaped roof tiles, J-shaped roof tiles, and J-shaped sleeve roof tiles, the value of width B described in Table 2 of JIS A 5208 can be adopted.

The area of each of the two glazed partial regions is such that when the clay-fired building material of this embodiment is placed on a horizontal surface, the back surface and the two glazed partial regions are vertically arranged on the horizontal surface. The area on a horizontal plane obtained by projection.

[4] Other preferred embodiments (4-1)
In the first and second aspects of the present invention, from the viewpoint of better bending fracture strength (as in the bending test of JIS A 5208 J-shaped and S-shaped stiles, a steel circle is formed along the valley bottom line on the back side of the building material. From the bending strength against the load of the type that pressurizes with a rod),
A clay-fired building material according to the first to second aspects of the present invention, wherein the length of the back side glaze layer in the valley bottom line direction is at least 40% of the total length of the valley bottom line,
(I) Of the back side surface area of the building material covered by the back side glaze layer, the valley bottom line or an area in the vicinity thereof, and each point belonging to the area is from each side to which both ends of the valley bottom line belong. A building material backside surface region that is at least 14%, more preferably at least 9% of the total length of the valley bottom line in the direction of the valley bottom line,
Or (ii) a front surface area of the building material facing the back surface area of the building material of (i),
Is preferably smooth.

The length in the valley bottom line direction of the back side glaze layer here is defined as the maximum value of the length in the valley bottom line direction in the substantially belt-shaped back side glaze layer. The length of the bottom side glaze layer in the valley bottom line direction is at least 40%, more preferably 45% or more, and in terms of a preferable upper limit value, 91.5% or less, more preferably 70 to 87%. Is.

The term “smooth” as used herein more specifically refers to a partial structure in which the surface area of the building material is raised or depressed (for example, a raised structure such as a reinforcing rib, a depressed structure of a depressed hole or a through hole, a stepped structure, etc.). It does not have. Examples of such a partial structure include those formed by press molding using a mold.

When a load is applied to the raised or depressed partial structure and the surrounding area, the amount of displacement due to the load in this area becomes almost discontinuous due to the abrupt change in the thickness of the building material, causing distortion. It will be easier. As a result, the raised or depressed partial structure tends to be a starting point of bending failure.

For this reason, there is no ridge or recessed partial structure in the surface area of the building material of (i) or (ii), more preferably (i), more preferably (i), and more preferably (i) and (ii), which is particularly susceptible to load. However, it is advantageous in the first place from the viewpoint of good bending fracture strength.

Further, the vicinity of the valley bottom line means that when the thickness of the clay-fired building material is D, a substantially strip-shaped region (width of 1.5D in total) having a width of 0.75D extending on both sides along the valley bottom line, In other words, it has a width of 1.5D perpendicular to the valley bottom line on the back side of the clay-fired building material, and refers to a substantially strip-shaped region extending in the direction along the valley bottom line (Test Example 4). reference).

In (i) above, it is often required that at least 14%, more preferably 9%, of the total length of the valley line is separated from each other in the clay roof tile and the like. This is a consideration.

Furthermore, as a more preferred embodiment of the above (i) or (ii),
A clay-fired building material according to the first to second aspects of the present invention, wherein the length of the back side glaze layer in the valley bottom line direction is at least 40% of the total length of the valley bottom line,
(Iii) Of the back side surface area of the building material covered by the back side glaze layer, each point belonging to the area is located at least in the valley bottom line direction from the sides to which both ends of the valley bottom line belong. 14% of the total length, more preferably 9% away from the building material backside surface area, or (iv) the building material backside surface area facing the building material backside surface area of (iii),
Is preferably smooth.

In other words, among the aspects (i) and (ii), particularly the entire back surface [the above (iii)] of the building material covered with the back surface glaze layer, or the surface area of the building material facing this is smooth. Preferably.

(4-2)
In the first and second aspects of the present invention, a surface side glaze layer may be formed on the surface of at least 70% of the surface of the clay-fired building material.

This is a normal and well-known glaze process, and any well-known glaze can be used.

[5] Relationship with Prior Art Although the cited document 2 mainly describes a technique for reducing the weight by providing a reinforcing rib on the back surface, separately, claim 6, paragraph 0015, 0078 to citation of the cited document 2. 0083, 0086 to 0092, 0098 and claim 6; in particular, claim 6, paragraphs 0079, 0089 and 0098, a part of the back surface of the roof tile body is formed thin, and thereafter, the glaze having a lower melting point than the roof tile body. There is also described a lightweight roof tile which is fired at a predetermined temperature after at least a part of the back surface is subjected to. According to this, the glaze penetrates into the cracks, cracks, etc. and acts as a binder so that the strength reduction due to the cracks, cracks, etc. is completely eliminated, and it is possible to obtain the strength as the theoretical value while aiming at integration. Since the wall thickness can be increased apparently, it is said that the roof tile can be made lighter in weight and comparable in strength to conventional products. And as an example thereof, roof tiles (think of as J-shaped roof tiles) in which the central portion 34, which is a part of the back surface, is glazed are produced in Examples 1 and 3 (see paragraphs 0087 to 0092 of the cited document 2). (See FIG. 63 of Cited Document 2).

The roof tile specifically shown in the embodiment of the cited document 2 is a J-shaped roof roof and is common to the object of the present invention.

However, it is not clear whether or not there is a protruding structure in the linear portion on the front surface corresponding to the end of the valley bottom line.

Even if there is a structure in which a linear portion on the side surface of the surface corresponding to the end of the valley bottom line is bulged, the back glaze layer specified in the central portion 34 in FIG. In paragraphs 0086 and 0089 (Example 1)], there is no description or suggestion about the limitation on the position of the back side glaze layer in the direction of the valley bottom line.

Therefore, it must be said that the cited document 2 does not describe or suggest the first aspect of the present invention.

Further, the cited document 2 merely refers to "a part of the back surface" (paragraphs 0086 and 0089 of the cited document 2), and there is no explicit description about how wide the back side is glazed. Although FIG. 63 of the cited document 2 shows the strip-shaped central portion 34 which is said to be glazed, this is also only a schematic diagram and how exactly can be read from this drawing. Unknown.

Therefore, also in this sense, there is no description or suggestion of the second aspect of the present invention.

Further, in the cited document 2, there is no description or suggestion that it is preferable to arrange the back side glaze layer symmetrically with respect to the valley bottom line.

As the clay for producing tiles, clay for producing Sekishu tiles (rough land A) was used.

The particle size distribution is shown in Table 2 below. The particle size distribution is measured by sedimentation measurement according to JIS A 1204 (2009).

[Test Example 1]
The Sekishu tile manufacturing company manufactured the Sekishu tile by using the waste land A as the clay for producing the Seki tile, and then the J-shaped white background clay tile after glazed surface [Glazed on the surface, dimension classification 53B (length: 295 mm, width 315 mm) , JIS A 5208, Table 2]], on the back side thereof, silver black (mainly SiO ₂ : 37%, Al ₂ O ₃ : 9%, MnO: 23%, Fe ₂ O ₃ : 7%, CaO: 6%). Glazed).

On the front side of the J-shaped roof tile, a region having a length of 38 mm from the bottom to the head over almost the entire length of the roof of the roof tile [12.9% of the total length of the valley bottom line (=100×38/ 295)] has three steps (water reversal walls), and the thickness is thicker toward the hip side [1 mm per step, a total of 2 mm, the inclination angle on each valley bottom line (protrusion start point and height). The angle formed by the line segment connecting the point at which is the maximum first and the plane on the ridge start point is 45 degrees or more, respectively, see FIG. 5(a2)]. The three-step difference corresponds to a=11.3 mm, b=13.5 mm, c=14.5 mm, d=19.1 mm, e=12.8 mm, f=50 mm in FIG. 5(a2).

The glazed areas were 2.5 cm, 5, 7 and 9 cm away from the buttocks, respectively, with the valley bottom line as the center line, and 7 cm width (14 cm width in total) on both sides to the head of the clay tile. After glazing, it was dried at room temperature for about 1 hour, then heated to 1185° C. at a temperature rising rate of 100° C. per hour using an electric furnace, held for 40 minutes, and then cooled in the furnace. The plate-shaped test body thus obtained was measured for water absorption and then dried at 110° C. for 24 hours to measure the bending fracture load (measured in accordance with the bending test for J-shaped and S-shaped roof tiles defined in JIS A 5208). I went. The measurement was performed using a Shimadzu autograph (AG-2000C). Table 3 shows the measurement results and the improvement rate of the bending fracture load with respect to the tile that is not glazed 2.5 cm from the bottom. In addition, the measurement was performed for each roof tile three times, and the average value was obtained. When the thickness of the roof tile was measured after the measurement, it was 14 mm.

From this table, when the glazed width is 14 cm (total glazed width of 44.4% of the total back side width), the unglazed width from the buttocks is 5 cm (the ratio of the valley bottom line included in the back side glazed layer is 83.1%). ), the bending fracture strength is highest.

The decrease in the unglazing width, that is, the increase in the bending area due to the increase in the glaze area, is considered to be due to the decrease in defects that are the starting points of fracture due to the glaze. However, when the unglaze width is reduced from 5 cm to 2.5 cm, the strength is decreased. It is considered that the thickness of the base material around the roof tile portion has an effect on this factor. Between 2.5 cm and 5 cm, a step (about 1 mm) is formed on the front side of the roof tile to prevent rainwater from wrapping around to the back side, facing the end of the valley line with a width of 38 mm from the hip. It crosses a linear part on the front side. Therefore, the base material from the step to the hip is about 2 mm thicker than the head to the step (water repellent wall). Since the strength increases as the thickness increases, the strength of the base material increases at the step. As the strength increases, the deformation due to the load decreases. Considering this together with the experimental results, when the non-glazing width is 5 cm, the step is not glazed on the buttocks, and the strength of the thickened base material is not increased by the glaze. On the other hand, when the unglaze part is 2.5 cm, the strength of the part where the base material in the vicinity of the step is thickened by 2 mm is increased by the glazing. That is, there is a difference in strength of the base material around the step between the case of 2.5 cm and the case of 5 cm. From this, it can be judged that the difference in strength of the base material with the step as the boundary is smaller in the case of 5 cm than in the case of 2.5 cm. That is, when the glaze width is 5 cm, the strength uniformity in the portion above the valley bottom line (or more accurately, the linear portion on the front side facing the valley bottom line) that is loaded in the bending fracture test is 2 glazed. It is considered to be larger than the case of 0.5 cm, and the strain when a linear load is applied is also smaller.

If the push rod can be loaded along the surface of the roof tile during the bending fracture test, it is considered that the bending fracture strength will be higher at 2.5 cm where the part with high base strength is formed, but in the actual test, along the unevenness of the surface It is impossible to apply a load. Therefore, it is considered that the glazing method (here, 2.5 cm) in which the strength of the base material greatly changes at the boundary of the step causes stress to be easily generated around the step, resulting in a strength lower than 5 cm.

The ratio (%) of valley bottom lines included in the glazed area on the back side of each J-shaped white clay tile having a non-glazing width of 2.5, 5, 7, and 9 cm from the hips was 91. 5%, 83.1%, 76.3% and 69.5%.

[Test Example 2]
The Sekishu tile manufacturing company manufactured the Sekishu tile by using the waste land A as the clay for producing the Seki tile, and then the J-shaped white background clay tile after glazed surface [Glazed on the surface, dimension classification 53B (length: 295 mm, width 315 mm) , JIS A 5208, Table 2], and the same glaze of silver black as in Test Example 1 was applied to the back side.

In addition, on the front side surface of this J-shaped roof tile, as in Test Example 1, within a region having a length of 38 mm from the bottom to the head of the roof tile [12.9% of the total length of the valley floor line (=100×38/295). )] is formed with three steps (water return wall) [see FIG. 5(a2)].

The glazed area was 5 cm away from the bottom of the clay tile, with the valley bottom line as the center line and the width of 6, 7 and 8 cm on each side to the head of the clay tile.

After glazing, it was dried at room temperature for about 1 hour, then heated to 1185° C. at a temperature rising rate of 100° C. per hour using an electric furnace, held for 40 minutes, and then cooled in the furnace. The plate-shaped test body thus obtained was measured for water absorption and then dried at 110° C. for 24 hours to measure the bending fracture load (measured in accordance with the bending test for J-shaped and S-shaped roof tiles defined in JIS A 5208). I went. The measurement was performed using a Shimadzu autograph (AG-2000C). The measurement results are shown in Table 4. In addition, the measurement was performed for each roof tile three times, and the average value was obtained. When the thickness of the roof tile was measured after the measurement, it was 14 mm.

From Table 4, when the unglaze width from the bottom of the clay tile is 5 cm (when the back side glaze layer is finished before reaching the step), the bending glaze strength is the highest when the glazed width is 14 cm. I understand.

Here, the back side glaze layers having a glazed width of 12 cm, 14 cm and 16 cm were 38.1%, 44.4% and 50.8% of the back side total width of the J-shaped white clay tile, respectively. This is because the width of the two partial areas of the back side glaze area with the valley line as the boundary is 19.1%, 22.2% and 25.4% respectively based on the total width of the back side of the J-shaped white clay tile. Equivalent to occupying the width.

The ratio of the valley bottom line contained in the back side glaze layer was 83.1% [(245/295)×100].

[Test Example 3]
A J-shaped roof tile, which was manufactured by Sekishu Tile Manufacturing Company using clay A for use in Sekishu tile production, was scraped from the front surface of the J-shaped roof molding to a depth of approximately 4 mm, and then glazed on the front surface after drying. The same as the test example 1 was glazed on the back side of the white clay roof tile (finished to be glazed on the front surface, dimension section 53B (length: 295 mm, width 315 mm), see Table 2 of JIS A 5208).

In addition, on the front surface of this J-shaped roof tile, as in Test Example 1, within a region having a width of 38 mm from the bottom to the head of the roof tile [12.9% of the total length of the valley bottom line (=100×38/295)]. ] Is formed with three steps (water return wall) [see FIG. 5(a2)].

The glazed area was about 5 cm away from the buttocks, centered on the valley bottom line, and 7 cm wide (14 cm wide in total) on each side to the head of the clay tile, and after glazed, it was dried at room temperature for about 1 hour. For comparison, a J-shaped white clay clay tile was prepared in which the front side surface was shaved by 4 mm and only the front side surface was glazed. These two types of roof tiles were heated to 1185° C. at a heating rate of 100° C. per hour using an electric furnace, held for 40 minutes, and then cooled in the furnace. The plate-shaped test body thus obtained was measured for water absorption and then dried at 110° C. for 24 hours to measure the bending fracture load (measured in accordance with the bending test for J-shaped and S-shaped roof tiles defined in JIS A 5208). I went. The measurement was performed using a Shimadzu autograph (AG-2000C). Table 12 shows the bending fracture measurement results of the two types of roof tiles and the improvement rate of the bending fracture load with respect to the roof tile whose back surface is not glazed. When the thickness of the roof tile was measured after the measurement, it was about 10 mm, and the weight was 2142 g (back side glazed) and 2135 g (back side non-glazed).

From this table and the test results, it was found that it is possible to give strength of about 2200 N to a roof tile having a weight of about 2200 g by applying glaze on the back surface.

The width of the back side glaze layer was 44.4% based on the total width of the J-shaped white clay tile, and the width of each partial glaze area when divided into two partial glaze areas by the valley bottom line was 22.2. %Met.

The ratio of the valley bottom line contained in the back glaze layer was 83.1%.

[Test Example 4]
The Sekishu tile manufacturing company manufactured the clay for producing Sekishu tile using the wasteland A, and the J-shaped white background clay tile after glazing [dimension classification 53B (length: 295 mm, width 315 mm), JIS A 5208 On the back side of [Table 2], the diameter at the position of 5,10,15,20 cm from the butt on the parallel line that is 1,2,3 cm away from the valley bottom line in the direction of the ridge, with the roof bottom line as the reference A cylindrical hole having a diameter of 2.5 mm and a depth of 4 mm was formed with a drill. Four holes were formed at the same position on the valley bottom line (see FIG. 6).

Next, using an electric furnace, it was heated to 1185° C. at a heating rate of 100° C. per hour, held for 40 minutes, and then cooled in the furnace. The bending fracture load (measured according to the bending test of the J-shaped and S-shaped roof tiles specified in JIS A 5208) was measured on the obtained J-shaped roof tile test body. The measurement was performed using a Shimadzu autograph (AG-2000C). Table 6 shows whether the cross section of the cylindrical hole formed in the fracture surface generated by the bending test appears. The thickness of the central portion of the J-shaped roof tile after the test was measured and found to be about 14 mm.

From this table, in order to improve the bending failure load of J-shaped roof tiles, there should be no hole-like structure that could become the starting point of failure during bending test in the area up to 1 cm to the left and right of the valley bottom line. Is considered desirable.

[Test Example 5]
The Sekishu tile manufacturing company produced the glazed J-shaped white clay tiles using the wasteland A as clay for producing Sekishu tiles [Dimension classification 53B (length: 295 mm, width 315 mm), Table 2 of JIS A 5208]. On the back side of the reference], the same silver-black glaze as in Test Example 1 was applied. The glazed area is 2.5 cm away from the bottom of the clay tile, with the valley bottom line as the centerline, and the width of 7 cm to the head of the clay tile on both sides, and 2.5 cm away from the bottom of the clay tile. The center line was set at a position 2 cm away from the valley bottom line on the water return side, and the width was 7 cm on both sides to the head of the clay tile. This corresponds to a width of the glazed area on the water repelling side of 5 cm and a width of the glazed area on the side opposite to the water repelling side of 9 cm with the valley bottom line as the center.

After glazing, it was dried at room temperature for about 1 hour, then heated to 1185° C. at a temperature rising rate of 100° C. per hour using an electric furnace, held for 40 minutes, and then cooled in the furnace. The plate-shaped test body thus obtained was measured for water absorption and then dried at 110° C. for 24 hours to measure the bending fracture load (measured in accordance with the bending test for J-shaped and S-shaped roof tiles defined in JIS A 5208). I went. An Shimadzu autograph (AG-2000C) was used for the measurement. The measurement results are shown in Table 14. In addition, the measurement was performed on three tiles for each roof tile, and the average value was obtained. When the thickness of the roof tile was measured after the measurement, it was 14 mm.

From this table, it was found that bringing the center of the glazed region to the valley bottom line has an advantageous effect on the bending fracture load.

In each case, the width of the glazed area was 44.4% based on the total width of the J-shaped white clay tile, and the ratio of the valley bottom line included in the back side glazed layer was 91.5%. there were.

However, when dividing into two partial glazed areas by the valley line, in the case of glazed around the valley line, the width of each partial glazed area is based on the entire width of the J-shaped white clay tile. 22.2%, which is the same, but in the case where the glazed case was centered on the part closer to the draining side by 2 cm from the valley bottom line, it was 15.9% and 28.6%, respectively.

Claims (13)

A clay-fired building material having a front surface, a back surface, and a thickness that is a distance between the two surfaces,
The clay-fired building material is curved in a concave shape in the thickness direction from the front side surface to the back side surface, and has a gutter-shaped concave curved shape,
On the back side surface, along the valley bottom line of the concave curved shape, and the back side glaze layer is formed as a substantially strip-shaped region including the valley bottom line,
The valley bottom line refers to a linear portion that passes through the lowest portion of the gutter-shaped concave curved shape when the clay-fired building material is temporarily installed on a horizontal plane,
The clay-fired building material is further
It has a protruding partial structure so as to cross a linear portion on the front side surface facing at least one end of the valley bottom line on the back side surface, and the back side glaze layer faces the protruding partial structure. It is finished by the time it reaches the back side area,
Here, the end portion of the valley bottom line refers to a linear portion extending from one end of the valley bottom line to the other end, and the length in the valley bottom line direction is 24% or less of the total length of the valley bottom line. Good,
A water repellent wall or a waterproof wall is formed on the front side surface, and the water repellent wall or the waterproof wall is configured as a raised partial structure, and the back side glaze layer is the valley bottom line of the clay-fired building material. A clay-fired building material, characterized in that it starts from one of the sides perpendicular to and ends by the time it reaches the back side surface region facing the water repellent wall or the waterproof wall . When the back side glaze layer is divided into two glazed partial regions by the valley bottom line,
The width of each of the two glazed partial regions is within a range of 15 to 30% of the total width of the back surface of the clay-fired building material,
The clay-fired building material according to claim 1, wherein the entire width of the back-side surface refers to a maximum width on the back-side surface of the clay-fired building material in a direction perpendicular to the valley bottom line. The length of the root line direction of the backside surface glaze layer, Ri least 40% der of the total length of the valley line,
(I) Of the back side surface area of the building material covered by the back side glaze layer, the valley bottom line or an area in the vicinity thereof, and each point belonging to the area is from each side to which both ends of the valley bottom line belong. , A building material back side surface region that is separated by at least 14% of the entire length of the valley floor line in the valley floor line direction,
Or (ii) a front surface area of the building material facing the back surface area of the building material of (i),
Is smooth,
Here, the vicinity of the valley bottom line means that when the thickness of the clay firing building material is D, a width of 1.5D is perpendicular to the center of the valley firing line on the back side surface of the clay firing building material. The clay-fired building material according to claim 1 or 2, wherein the clay-fired building material is a substantially strip-shaped region extending in a direction along the valley bottom line. The clay firing building material according to any one of claims 1 to 3, wherein the back side glaze layer is symmetrically arranged with the valley bottom line as an axis. The clay-fired building material according to claim 1, wherein the clay-fired building material has a thickness of 6 mm to 16 mm. The clay-fired building material according to any one of claims 1 to 5, wherein a weight per unit surface area of the clay-fired building material is 1.30 to 3.52 g/cm2. The clay-fired building material according to any one of claims 1 to 6, wherein a surface-side glaze layer is formed on at least 70% of the surface of the surface. The clay firing building material according to claim 1, wherein the back side glaze layer is formed of a glaze having a composition containing at least silicon and aluminum. The clay-fired building material according to claim 1, wherein the clay-fired building material is a clay roof tile. The partial structure of at least a part of the water repellent wall or the waterproof wall at least at a portion exceeding 8.5% of the valley bottom line in the valley bottom line direction from the water repellent wall or the waterproof wall side of the valley bottom line. The clay-fired building material according to any one of claims 1 to 9, wherein: The clay-fired building material according to any one of claims 1 to 10, wherein a length of the water return wall or the waterproof wall in the valley bottom line direction is 3% to 24% of the entire length of the valley bottom line. The clay-fired building material according to any one of claims 1 to 11, wherein, when the thickness of the clay-fired building material is D, the rising height of the water repellent wall or the waterproof wall is 0.05D to 0.2D. .. The clay-fired building material according to any one of claims 1 to 11, wherein the rising height of the water return wall or the waterproof wall is 1 to 3 mm.