JPH0536898Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to tatami mats that have traditionally been used as flooring materials in Japan, and particularly to tatami mats suitable for judo halls.

[Conventional technology]

Conventional tatami mats include, for example, Japanese Utility Model Publication No. 56-54276,
Utility Model Publication No. 57-15315 or Utility Model Publication No. 15315-
As shown in Japanese Patent No. 100428, it is known that the tatami floor is made of foamed resin instead of straw to reduce weight and prevent corrosion due to moisture.

However, in the structures shown in each of the above-mentioned publications, a moderately flexible felt is provided above the core material as a cushioning material, but since styrofoam is used as the core material, this cannot be used. When used for a judo hall, it is too hard and poses a danger to competitions, and its shock absorption and strength are insufficient, making it unsuitable for this type of use.

On the other hand, in consideration of its use in judo halls, there was a product designed to improve shock absorbing power in the 1980s.
As shown in Publication No. 155858, a structure has been proposed in which a stress dispersion layer made of polyolefin-based low-foaming material or the like is provided between a lower synthetic resin foam and an upper synthetic resin foam. There is. However, in this case, the structure of the tatami as a whole is too soft and cannot obtain sufficient strength, and the stress dispersion layer itself is made of a soft material, so it has the disadvantage that a sufficient stress dispersion effect cannot be obtained. are doing. In other words, tatami mats used as flooring materials are generally formed to a roughly fixed thickness, but the thickness of the lower layer synthetic resin foam that is the core material is determined by the stress dispersion layer made of low foam material, etc. limited by its existence, it is not possible to obtain sufficient strength. Further, the stress dispersion layer made of polyolefin-based low foam material is itself relatively soft. Therefore, it is not possible to impart appropriate hardness and strength to tatami mats,
Another problem is that when a strong impact is received from the tatami surface, the stress cannot be sufficiently dispersed throughout the lower synthetic resin foam, making it extremely unsuitable for use in judo halls. It has points.

Therefore, as a solution to the above-mentioned problems, Japanese Utility Model Application No. 61-87829 discloses that the lower surface of the core material is made of a polymeric foam such as polyethylene foam beads or polyethylene-polystyrene copolymer foam. A structure is disclosed in which a soft foam member layer with excellent elasticity is provided on the core material, and a plywood board for impact dispersion and a polyethylene foam layer are provided on the upper surface side of the core material.

On the other hand, as another type of tatami suitable for judo halls,
Publication No. 52-136423 discloses that a set of two reinforcing members are provided on both upper and lower surfaces of a core material made of closed-cell plastic foam, and the reinforcing members are stacked one on top of the other so that the grain directions are perpendicular to each other. A structure in which a hard felt is provided is disclosed.

In addition, in Japanese Utility Model Application Publication No. 49-13504, a core material made of a synthetic resin material such as polyethylene or polystyrene is used, and polyethylene or polypropylene is added to the upper and lower surfaces of the core material for the purpose of improving strength. A structure is disclosed in which a plastic molded body containing an inorganic filler is provided, and a buffer plate made of foamed polyethylene or the like is further provided on the upper surface side of the plastic molded body provided on the upper surface side of the core material.

Furthermore, in Japanese Patent Publication No. 54-4180, a hard urethane foam with some bubbles destroyed by compression was used as the core material, a lining was provided on the lower side of the core material, and a tatami surface was provided on the upper side. structure is disclosed.

[The problem that the idea attempts to solve]

However, in the structure disclosed in the above-mentioned Japanese Utility Model Publication No. 1987-87829, it is essential to provide a soft foam layer on the bottom side of the core material, so it has the impact resistance required for judo hall tatami mats. In order to obtain functions such as shock absorption and compression resistance, the structure has become complex due to its multilayer structure. Therefore, there is a problem in that the number of parts increases, leading to an increase in costs. Furthermore, plywood boards used for impact dispersion have a problem of hygroscopicity, which is disadvantageous for tatami mats, and are weak against impact and easily break.

Furthermore, in the structure disclosed in Japanese Utility Model Publication No. 52-136423, the grain directions are made orthogonal to each other between the core material and the hard felt for the purpose of reinforcing the core material and preventing the tatami from warping. Not only does the structure of the tatami become extremely complex, as the reinforcing members overlapped with each other, but when this tatami is used as a tatami for flexible play areas, wood must be used as the reinforcing member. There is a problem that the impact resistance is inferior because of this.

On the other hand, in the structure disclosed in Japanese Utility Model Application Publication No. 49-13504, plastic molded bodies are provided on the upper and lower sides of the core material in order to supplement the strength of the core material made of synthetic resin materials such as polyethylene and polystyrene. This increases the strength of the tatami as a whole. However, the shock absorption and compression resistance required for tatami mats for judo halls are becoming lower. For this reason, it is not possible to provide a function that can accurately attenuate the impact applied during, for example, Ukemi in judo, reduce pain for the athlete, and prevent injury.

In addition, the structure disclosed in Japanese Patent Publication No. 54-4180 has only the above-mentioned urethane foam layer as a layer for absorbing impact, so although the structure is simple, such In structures, when dynamic loads are repeatedly applied,
The problem is that it is difficult to restore the tatami to its original state easily, and it cannot provide the compression resistance required for judo hall tatami.

Therefore, an object of the present invention is to provide a tatami mat for a judo hall that has the impact resistance, shock absorption, and compression resistance necessary for a tatami mat for a judo hall, and that has a simple structure.

[Means to solve the problem]

In order to solve the above problems, the tatami mat for judo halls of the present invention provides a backing sheet on the lower surface of the hard foam resin layer made of a copolymer of polyethylene and styrene that forms the core material, and The hard foam resin layer is formed by laminating polypropylene plates, felt, and tatami mats in this order on the upper surface of the resin layer. Roll the combined foam by 30% in the thickness direction.
It is characterized by being formed by compressing within the range of ~70% and partially destroying the bubbles.

[Effect]

With the above structure, the impact applied to the tatami mat is partially absorbed by the felt provided on the back side of the tatami mat surface, and the stress is sufficiently dispersed throughout the hard foam resin layer by the polypropylene plate. The dispersed stress is generated by partially destroying the cells of the polyethylene-styrene copolymer foam.
The impact is reliably attenuated by being absorbed by the hard foam resin layer with high impact absorption capacity.

In other words, in this tatami mat for judo halls, the hard foam resin layer is formed by partially destroying the cells of a polyethylene-styrene copolymer foam, and has a high shock absorption ability. There is no need to further provide a shock absorbing layer on the lower surface side of the device, and the applied shock can be reliably attenuated. Furthermore, the hard foam resin layer not only has high impact resistance and compression resistance, but also has little deformation due to aging, temperature changes, and the like. Further, the above-mentioned felt improves the feel of the tatami surface, suppresses cushioning properties, and provides a hardness that is neither too hard nor too soft and suitable for use as tatami mats for judo halls.

Therefore, although this tatami mat for judo halls has a simple structure, it has a backing material on the bottom side of the hard foam resin layer that forms the core material, and a polypropylene plate, felt, and tatami face on the top side of the hard foam resin layer. It can provide the impact resistance, shock absorption and compression resistance necessary for judo hall tatami.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG.

The tatami mat for judo halls according to the present invention is provided with a back sheet 2 on the lower surface of a hard foam resin layer 1 made of a copolymer of polyethylene and styrene forming a core material, and
It has a structure in which a polypropylene plate 3, felts 4 and 5, and a tatami facing 6 are laminated in this order on the upper surface of the hard foam resin layer 1.

The above-mentioned back sheet 2 is made of a needle-punched fiber sheet, etc., and is provided to prevent moisture on the underside of the tatami mat and to prevent damage to the hard foam resin layer 1 due to being tightened by sewing threads. .

In this embodiment, the hard foam resin layer 1 has a plate shape with a thickness of 42 mm. This hard foam resin layer 1 is made by dispersing polyethylene particles in suspension, adding a styrene monomer containing a polymerization catalyst thereto, polymerizing the monomer in the polyethylene particles, and impregnating this with an easily volatile blowing agent. The foamed polyethylene-styrene copolymer particles obtained in this example are compressed in the thickness direction using a roll or the like to 50% to partially destroy the bubbles. It is made up of

The reason why the hard foam resin layer 1 has the above composition is as follows. That is, the composition structure of polystyrene foam alone is preferable as a core material for ordinary tatami mats because it has a low degree of shrinkage, but it is too hard for tatami mats for judo halls. In addition, with a composition structure made of foamed polyethylene alone, the air bubbles are destroyed during long-term use, causing the thickness to become thinner and deformed, as well as shrinking due to temperature changes, creating gaps between the tatami mats, making it unsuitable for use as tatami mats for judo halls. There is great danger in using this. In addition, problems such as buckling may also occur. Therefore, in order to eliminate the drawbacks of the above-mentioned two materials and to combine the characteristics of each material, the hard foamed resin layer 1 having the above-mentioned composition structure was used.

The polypropylene board 3 has a thickness of 3 mm in this embodiment, and provides appropriate hardness and strength to the entire tatami mat. This polypropylene plate 3 itself has hardness and tenacity, and has the characteristics that it does not easily crack or break even when subjected to impact, is weather resistant, and has little shrinkage over time. . Furthermore, by using the hard polypropylene plate 3 and disposing it on the hard foam resin layer 1 as described above, the impact received from the tatami surface is absorbed by the hard foam resin layer 1.
This will provide the ability to sufficiently distribute the information throughout the area.

The felts 4 and 5 are made of needle-punched filament laminates of wool, synthetic fibers, or plastic, and have appropriate flexibility, suppress cushioning properties, and are not too hard or too soft. It not only has hardness but also improves the feel of the tatami surface. In this embodiment, both felts 4 and 5 each have a plate shape with a thickness of 6 mm, and have a two-layer structure with a total thickness of 12 mm. The tatami surface 6 is made of polypropylene material or woven straw grass.

On the other hand, the back sheet 2, hard foam resin layer 1, and polypropylene plate 3 are adhered to each other with an adhesive. As this adhesive, natural rubber type, synthetic rubber type, synthetic resin type, hot melt type, etc. are used. In addition, the back sheet 2, hard foam resin layer 1, polypropylene plate 3, and felts 4, 5 are as follows:
The sewing processing section 7... is integrated. The sewing parts 7 are machine-stitched at five locations in the width direction of the tatami mat at approximately equal intervals and parallel to the longitudinal direction of the tatami mat. Then, the tatami facing 6 is glued so as to cover the upper surface of the upper felt 5, the end surfaces of the back sheet 2, the hard foam resin layer 1, the polypropylene plate 3, and the felts 4 and 5, and the bottom peripheral edge of the back sheet 2. It is attached with adhesive.

In the above structure, when an impact is applied to the tatami mat for the judo hall from the tatami facing side 6, this impact force is first partially absorbed by the felts 4 and 5, and then passed through the polypropylene plate 3 to the hard foam resin. It joins layer 1 and is absorbed by these members. In particular, the hard foam resin layer 1 made of a copolymer of polyethylene and styrene has a high impact absorption ability, so that the applied impact force is accurately attenuated.

Furthermore, since the hard foam resin layer 1 has appropriate hardness and tenacity, it is difficult to crack or chip even when subjected to a large impact, is weather resistant, and has little shrinkage over time and does not lose its shape. .
As described above, since the hard foam resin layer 1 has excellent impact resistance and compression resistance, together with the polypropylene plate 3 and the like for stress dispersion, a reliable impact force damping effect can be obtained. As a result, in this tatami mat for judo halls, it is possible to reliably attenuate the applied impact, for example, without providing an additional impact-absorbing layer on the lower surface side of the hard foam resin layer 1. Therefore,
This tatami mat for judo hall has a back sheet 2 on the lower side of the hard foam resin layer 1, and a polypropylene plate 3, felts 4 and 5, and a tatami face 6 on the upper side of the hard foam resin layer 1.
Although it has a simple structure, it can provide impact resistance, shock absorption, and compression resistance necessary for a tatami mat for a judo hall.

In addition, felts 4 and 5 have moderate flexibility, relatively suppress cushioning properties, and absorb and release moisture depending on the humidity level, making them similar to traditional straw tatami mats. It gives a feel. Although these felts 4 and 5 can provide a certain stress dispersion effect, they are insufficient in their stress dispersion function. Therefore, a hard polypropylene plate 3 is interposed between the hard foam resin layer 1 and the felt 4. This polypropylene plate 3 temporarily absorbs the impact applied through the felts 4 and 5, and disperses the stress over the entire hard foam resin layer 1, which has a high impact absorption ability. Furthermore, since the polypropylene board 3 used for this judo hall tatami mat is thin and hard, the tatami mat as a whole has appropriate hardness and strength, and is set to a suitable thickness.

In other words, tatami cannot be considered good if it is too hard or too soft, and especially in the case of tatami for judo halls, if it is too hard, it will cause excessive pain to the competitors and will not absorb enough impact. and the safety of the athletes cannot be maintained. On the other hand, if it is too soft, your feet will dig into the tatami, making it difficult to use your feet and leading to injuries such as sprains.
In this tatami mat for judo halls, a thin polypropylene plate 3 is interposed between the hard foam resin layer 1 and the felt 4 to form a laminate consisting of the hard foam resin layer 1, the polypropylene board 3, and the felts 4 and 5. According to
Together with the hardness possessed by the hard foam resin layer 1, etc., this gives the entire tatami a suitable hardness. Further, the thicker the hard foamed resin layer 1 that forms the core material, the stronger the tatami can be, but the tatami used as a flooring material must be formed to have a substantially constant thickness. Therefore, a thin polypropylene plate with high strength 3
By providing as described above, the thickness of the hard foam resin layer 1 can be suppressed to 42 mm as in this embodiment, and sufficient strength can be obtained as a whole for the tatami mat, and the thickness can be maintained at a predetermined value.

Furthermore, since each member constituting the judo hall tatami of the present invention is made of a lightweight chemical product such as the hard foam resin layer 1, the entire tatami mat is lightweight and resistant to corrosion.

Further, the back sheet 2, the hard foam resin layer 1, the polypropylene plate 3, and the felts 4 and 5 are sewn, and the polypropylene board 3, the hard foam resin layer 1, and the back sheet 2 are attached to each other with adhesive. As a result, misalignment and wrinkles are less likely to occur, and each member is less likely to be damaged.

[Effect of idea]

As described above, the tatami mat for judo halls of the present invention is provided with a backing sheet on the lower surface of the hard foam resin layer made of a copolymer of polyethylene and styrene forming the core material, and a back sheet on the upper surface of the hard foam resin layer. , a polypropylene plate, felt, and a tatami surface are laminated in this order, and the above-mentioned hard foam resin layer is formed by foam-molding expandable polyethylene-styrene copolymer particles,
This polyethylene-styrene copolymer foam is compressed in the thickness direction by a roll or the like within a range of 30% to 70% to partially destroy the cells.

This has the effect of providing the impact resistance, impact absorption and compression resistance required for tatami mats for use in judo halls with a simple structure.

[Brief explanation of the drawing]

FIG. 1 is an explanatory longitudinal cross-sectional view showing one embodiment of the present invention. 1 is a hard foam resin layer, 2 is a back sheet, 3 is a polypropylene board, 4 and 5 are felt, and 6 is a tatami mat surface.

Claims (1)

[Scope of utility model registration request] A backing sheet is provided on the lower surface of the hard foam resin layer made of a copolymer of polyethylene and styrene that forms the core material, and a polypropylene plate, felt, and tatami surface are laminated in this order on the upper surface of the hard foam resin layer. The hard foam resin layer is formed by foam-molding expandable polyethylene-styrene copolymer particles, and compressing the polyethylene-styrene copolymer foam within a range of 30% to 70% in the thickness direction. A tatami mat for a judo hall characterized by being formed by partially destroying air bubbles.