JPH0684675B2 - Inorganic fiber tatami floor - Google Patents

Description

TECHNICAL FIELD The present invention relates to a lightweight tatami floor having excellent compressive strength, fire resistance and the like.

[Prior Art] Tatami has been used for a long time as a flooring material for Japanese-style rooms, and tatami mats mainly composed of straw are widely used with tatami mats made of rush and the like. . However,
With the mechanization of agriculture, straw has been cut into smaller pieces during harvesting work. Therefore, it is difficult to obtain domestic straws as a material for tatami mats, and some straws imported from foreign countries are used for tatami mats.

Due to this tendency, when tatami mats are manufactured using natural straw, the cost of raw materials affects the product cost, and the price of tatami mats becomes high. In addition, various kinds of insects and eggs thereof may be attached to the natural straw, or the straw may not be dried sufficiently. Therefore, in a tatami floor made of straw, insects may be swollen or the straw itself may rot and the required strength may not be maintained. is there.

Therefore, research has been conducted to reduce the amount of straw used, and to use lightweight resins, inorganic fibers, wood materials, and the like as substitutes for straw, and some have been implemented. For example, the actual exploitation 55-99
Japanese Patent No. 338 introduces a sutureless tatami in which a flame-retardant light material layer, a softball layer, a waterproof paper layer, etc. are laminated. Also,
The present applicant has also developed a tatami mat mainly composed of inorganic fibers, part of which has been introduced in JP-A-57-193664.

[Problems to be Solved by the Invention] A tatami floor, which uses a lightweight resin, an inorganic fiber, wood, or the like as a substitute for straw, is generally light in weight and therefore easy to handle. This lightness becomes more remarkable as the amount of synthetic foamed resin used increases.

However, many synthetic foamed resins generate toxic gas when a flame or the like occurs. Therefore, when the tatami floor burns, the poisonous gas generated may cause a serious accident. In addition, since the hygroscopicity is poor, the feel of the tatami mat is deteriorated.

On the other hand, tatami floors, which are mainly composed of inorganic fibers, have the advantage of being non-combustible. In order to obtain the required compressive strength, this tatami mat is formed by using a relatively large amount of inorganic fibers and mixing it with an organic binder. However, the use of a large amount of inorganic fibers not only diminishes the advantages of lightweight, but also increases the product cost. Further, the amount of the binder used to fix the inorganic fibers also increases. for that reason,
In a flame or the like, there is an increased risk that harmful gas will be generated due to the combustion of the binder, and the advantages of the noncombustible inorganic fiber will not be utilized.

Therefore, the present invention has a sufficient compressive strength even when the inorganic fibers are solidified at a relatively low density by improving the orientation of the inorganic fibers constituting the tatami mat, and a relatively small amount of the binder. The objective is to provide a tatami mat which is excellent in strength, lightness and safety by molding the inorganic fiber into a predetermined shape.

[Means for Solving the Problems] In order to achieve the object, the tatami mat of the present invention has a plurality of corrugated inorganic fiber layers laminated, and the inorganic fibers are three-dimensionally randomly oriented. However, they are intertwined with each other.

As the inorganic fiber, natural rock wool, asbestos or the like can be used. Further, it is also possible to use slag wool in which fibrous slag discharged as a by-product from a steelmaking plant is used. It is preferable to use long fibers having a diameter of 3 to 10 μm and an aspect ratio of about 1,000 to 20,000 as the inorganic fibers in order to provide the necessary strength and the stiffness of the tatami mat.

As the binder for binding the inorganic fibers, various polymer organic adhesives such as epoxy resin, phenol resin, urethane resin and melamine resin are used. Above all, it is preferable to use a phenol resin from the viewpoints of adhesive strength between fibers, heat resistant temperature, price and the like.

The inorganic fiber aggregate in which the inorganic fibers are arranged with the above-described orientation can be used alone as a tatami floor. Or, if necessary, plywood, wood layer, foamed resin layer, non-woven fabric, metal plate, cloth, film, etc.
It can also be used as a laminated body in which a waterproof sheet, a water absorbing sheet and the like are stuck together. For example, inorganic fibers have a certain degree of hygroscopicity by themselves, but they are sewn to the surface of tatami floors when laminating plywood, which has a breathing action, and absorbs water according to the humidity of the atmosphere The tatami mat is always maintained at a constant humidity and has a good feel.

[Operation] The aggregate of inorganic fibers constituting the tatami floor is manufactured by laminating a plurality of inorganic fiber sheets and compressing the laminated inorganic fiber sheets from the vertical direction while compressing the inorganic fiber sheets from the horizontal direction. . For example, in order to stack 10 layers of rockwool sheets on a belt conveyor, a method of continuously folding a thin layer of rockwool sheet at a right angle to the running direction of the belt conveyor, and a method of running thin layer of rockwool sheet on the belt conveyor. To fold in one direction continuously, 10
A method of continuously stacking thin rock wool sheets in the running direction of the belt conveyor, stacking 10 layers of thin rock wool sheets cut to the finished product size, placing this on the belt conveyor, and intermittently A method of driving the vehicle is adopted.

In the obtained inorganic fiber aggregate, for example, when the inorganic fiber sheet is laminated in 10 layers, the inorganic fibers are arranged in the orientation schematically shown in FIG.

That is, in each of the layers L _{1 to} L ₁₀ of the inorganic fiber sheet, the fiber components f _{1 to} f ₁₀ that were mainly in the horizontal direction are bent in the vertical direction due to the compression and contraction from the horizontal direction, and have a large number of wavy undulations. It has a curved shape. Also, inorganic fibers f ₁ ~f ₁₀ of the layers L ₁ ~L ₁₀ is in a state where intertwined in each layer L ₁ ~L ₃ and interlayer.

In this state, the inorganic fibers f _{1 to} f ₁₀ are fixed by the binder, so that in the obtained fiber assembly, the inorganic fibers are three-dimensionally oriented in various directions such as horizontal direction, vertical direction, and diagonal direction.
f _{1 to} f ₁₀ are oriented. Therefore, sufficient proof stress is obtained with respect to the force applied in the thickness direction, and the compression strength is improved. Moreover, since the inorganic fiber f ₁ ~f ₁₀ is intertwined among the layers L ₁ ~L _10, also eliminates the delamination in the layers L ₁ ~L ₁₀ occurs.

Moreover, since the inorganic fibers f _{1 to} f ₁₀ have a multilayer structure derived from the original inorganic fiber sheet, the force P ₀₀ applied to the surface of the fiber assembly is P ₁₁ to P ₁₁ to the uppermost layer L _1. It is dispersed in Pu ₃ and further finely dispersed as it goes to lower layers L _{2 to} L ₁₀ . That is, the force applied to one point on the surface of the fiber assembly
Since P ₀₀ is received in a wider area as it goes to the lower layer, the force applied per unit area is small in the lowermost layer L ₁₀ . Even from this fact, the compression strength and the bending strength of the inorganic fiber aggregate as a whole are excellent.

Further, even if there is some variation in the distribution density of the inorganic fibers in each of the sheets forming the layers L _{1 to} L ₁₀ , the variation is mitigated by stacking a plurality of inorganic fiber sheets. As a result, the obtained inorganic fiber aggregate has a stable quality in which the properties are not partially changed.

In this way, properties such as compressive strength and bending strength are improved, so that a tatami floor can be manufactured with a relatively small amount of inorganic fibers. For example, when simply molding the inorganic fibers to form a tatami mat, 200 to 250 kg / m ² of the inorganic fibers were required, while the inorganic fibers having the orientation shown in FIG. 1 were used. When arranged, the inorganic fibers of about 100 to 150 kg / m ^{3 have the} same strength.
Therefore, it is possible to reduce the amount of the inorganic fibers used for the tatami mat, and it is possible to obtain a non-combustible tatami mat which is excellent in strength, light weight, heat insulation and sound absorption.

[Example] Phenolic resin was sprayed at a ratio of 3% on rock wool having an average diameter of 4.5 µm and an aspect ratio of 10,000 produced from blast furnace slag, and then formed into a sheet having a width of 800 mm and a thickness of 7 mm. This rock wool sheet was continuously fed onto a conveyor to fold it into 10 layers to obtain a laminate.

While pressing the laminated body with a pair of upper and lower conveyor belts, under a state of being compressed to 25 mm, the traveling speed of the subsequent pair of upper and lower conveyor belts is compressed in the horizontal direction to reduce the fiber aggregate thickness of 25 mm. Got That is, by slowing the traveling speed of the conveyor toward the rear side, the preceding fibers are compressed in the conveyor traveling direction by the following fibers. Further, the swelling of the fibers in the thickness direction was prevented by applying a force from the upper and lower surfaces of the fiber assembly.

Next, the fiber assembly was kept in an atmosphere of 250 ° C. for about 3 minutes to develop the tackiness of the phenol resin, and the fiber assembly was molded.

The obtained fiber assembly has 3 parts as schematically shown in FIG.
The slag wool was arranged in a dimensionally random direction. Its density was 150 kg / m ³ , which was about 1/2 the weight of the conventional straw mat floor.

The following strength test was performed on this fiber assembly.

A 50 mm × 50 mm × 50 mm rectangular parallelepiped was cut out from the fiber assembly as a test piece, and a load was applied along the direction perpendicular to the surface until the thickness became 25 mm. FIG. 3 is a graph showing the relationship between the thickness reduction and the load at this time.

In addition, each numerical value 1.5, 2.0, 2.5, and 3.0 in FIG. 3 represents the compression ratio regarding the running direction of the fiber assembly. Also, the third
In the figure, a single-layer slag wool sheet molded to the same thickness without being compressed is Comparative Example 1, and a 10-layer slag wool sheet molded to the same thickness without being compressed is Comparative Example 2. Also shown.

As is clear from FIG. 3, the fiber assembly of this Example
It can be seen that it has excellent compressive strength required for tatami mats.

In addition, at a right angle to the direction of fiber swell 75 mm x 50 mm x 300 mm
The rectangular parallelepiped was cut out from the fiber assembly as a test piece, and a bending test was performed. At this time, from both longitudinal ends of the test piece
The test piece was supported at a point of 50 mm as a fulcrum, a predetermined force was applied to the central part of the span of 200 mm, and the amount of displacement given to the test piece was measured. FIG. 4 is a graph showing the relationship between the weight and the displacement thus obtained.

As is clear from FIG. 4, the fiber assembly of this Example
It can be seen that it has excellent bending resistance. For example, in order to give a displacement of 8 mm to the test body, it was necessary to apply a load of 10 to 13 kgf in the fiber assembly of this example. On the other hand, in Comparative Example 1, the same displacement is applied with a load of about 4 kgf and in Comparative Example 2 with a load of about 7 kgf. As described above, since the fiber assembly of this example has excellent bending resistance, the tatami floor made from this fiber assembly is difficult to bend and is easy to transport and handle.

[Effects of the Invention] As described above, in the tatami floor of the present invention, a plurality of inorganic fiber layers are stacked with many wavy undulations, and the inorganic fibers are randomly oriented in various directions and arranged. . Due to this peculiar fiber orientation state, a tatami mat having a sufficient strength can be obtained even when the inorganic fibers are molded at a relatively low density. Moreover, because of the low density, not only the amount of inorganic fiber used as a raw material can be reduced and the raw material cost can be reduced, but also the lightness and the sound absorbing property are excellent. In this way, according to the present invention, it is possible to manufacture a lightweight, non-combustible tatami floor having the advantages of the conventional straw tatami floor without using any straw.

[Brief description of drawings]

FIG. 1 schematically shows the fiber distribution of the fiber assembly that constitutes the tatami floor of the present invention, FIG. 2 is a diagram for explaining the state of propagation of compressive force, and FIGS. 3 and 4 are the present invention. It is a graph showing the compressive strength and the bending strength of the fiber assembly in an example, respectively. L _{1 to} L ₁₀ : Layer of inorganic fiber sheet f _{1 to} f ₁₀ : Inorganic fiber P ₀₀ : Tread pressure P ₁₁ , P ₁₂・ ・ ・ P ₂ n: Tread pressure dispersed in each layer

Claims (1)

[Claims] 1. A tatami mat of inorganic fibers, characterized in that a plurality of corrugated inorganic fiber layers are laminated, and the inorganic fibers are three-dimensionally randomly oriented and intertwined with each other.