JP2022109194A - Contamination diffusion inhibiting sheet - Google Patents

Abstract

To provide a contamination diffusion inhibiting sheet that can absorb a sufficient amount of a liquid harmful compound and can prevent a leak of a gaseous harmful compound.SOLUTION: A contamination diffusion inhibiting sheet 1 has a liquid holding layer 2 that absorbs and holds a liquid harmful compound, and a gas adsorbing layer 3 that is laminated on the liquid holding layer 2 and adsorbs a gaseous harmful compound. In the liquid holding layer 2, a water absorption ratio and an oil absorption ratio are at least 9, respectively.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to a stain diffusion suppression sheet.

Patent Literature 1 describes a conventional stain diffusion suppression sheet (“liquid absorption” in Patent Literature 1). The liquid absorbent described in Patent Document 1 can, for example, absorb and recover oil or the like that has flowed out onto a flat floor or road surface. The liquid-absorbent includes a liquid-permeable material layer, an impermeable layer overlaid on the liquid-permeable material layer, and a liquid-absorbent material disposed between the liquid-permeable material layer and the impermeable layer. The liquid-absorbent material can absorb and retain liquid that permeates the liquid-permeable material layer.

JP-A-8-311835

In the event that a volatile liquid hazardous compound leaks out, in order to prevent the spread of disaster, the causative agent, that is, the pollution source, should be confirmed, and the causative agent should be quickly absorbed, and the volatilizing gas should also be removed. need to be contained.

However, the liquid-absorbing material described in Patent Document 1 has a problem that if there is even a small gap between the impermeable layer and the liquid-permeable material layer, the gas volatilized from the liquid leaks.

In addition, in order to prevent the leakage of gas volatilized from the liquid, it has been considered to provide an adsorbent for adsorbing gaseous harmful compounds in the space between the impermeable layer and the liquid-permeable material layer. However, when the liquid absorbed by the liquid-absorbing material reaches the adsorbent, the gas adsorbing power of the adsorbent deteriorates and the gas cannot be adsorbed appropriately, resulting in the problem of gas leakage. obtain.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a pollution diffusion suppression sheet capable of absorbing liquid harmful compounds and suppressing leakage of gaseous harmful compounds. .

A pollution diffusion suppression sheet according to one aspect of the present invention includes a liquid-retaining layer that absorbs and retains liquid harmful compounds, a gas adsorption layer that adsorbs gaseous harmful compounds, the liquid-retaining layer, and the adsorption layer. and a breathable waterproof layer provided between and preventing the passage of liquid and allowing the passage of gas.

Further, in the above aspect, the pollution diffusion suppression sheet is a barrier layer provided on the side opposite to the liquid retention layer with respect to the gas adsorption layer in the thickness direction of the pollution diffusion suppression sheet to prevent passage of gas. is preferably further provided.

Further, in the above aspect of the pollution diffusion suppression sheet, the breathable waterproof layer preferably has a thickness dimension of 10 μm or more and 80 μm or less.

Further, in the above aspect of the pollution diffusion suppression sheet, it is preferable that the water absorption capacity and the oil absorption capacity of the liquid-retaining layer are respectively 9 times or more of the own weight of the liquid-retaining layer.

Further, in the above-mentioned aspect of the pollution diffusion suppression sheet, the liquid-retaining layer is composed of a fiber aggregate containing absorbent fibers, and the absorbent fibers form an inner layer portion and an outer hydrogel outer layer portion. It is preferable to have a multilayer structure containing

Further, in the pollution diffusion suppression sheet in the above aspect, it is preferable that the gas adsorption layer contains granular activated carbon, fibrous activated carbon, or a composite material thereof.

The pollution diffusion suppression sheet of the above aspect of the present invention has the advantage of providing a pollution diffusion suppression sheet that can absorb liquid harmful compounds and suppress leakage of gaseous harmful compounds. There is

FIG. 1 is a cross-sectional view of a contamination diffusion suppression sheet of Embodiment 1 according to the present invention. FIG. 2 is a cross-sectional view of a pollution diffusion suppression sheet according to Embodiment 2 of the present invention. FIG. 3 is a cross-sectional view of the desiccator used in the leak test of the example. FIG. 4 is a cross-sectional view of the glass cell used in the sealing test of the example. FIG. 5 is a graph showing the results of the leak test. FIG. 6A is a graph showing the gas concentration in the downstream space among the results of the sealing test. FIG. 6B is a graph showing the gas concentration in the upstream space among the results of the sealing test.

<Embodiment>
(1) Embodiment 1
The pollution diffusion suppression sheet 1 according to this embodiment will be described in detail below.

The contamination diffusion suppression sheet 1 is a sheet for quickly recovering liquid harmful compounds that flow out or dissipate on an outflow surface such as a floor surface. According to the pollution diffusion suppression sheet 1 according to the present embodiment, it is possible to quickly and appropriately recover the liquid hazardous compound, and to suppress the spread of the hazardous compound on the outflow surface.

As used herein, the term "liquid harmful compound" means a compound that is fluid and has the potential to adversely affect the human body. Examples of "liquid harmful compounds" include organophosphorus compounds, toxic industrial chemicals (TIC), light oil, kerosene, and heavy oil. Liquid hazardous compounds are volatile, and even if a mere absorption sheet absorbs liquid hazardous compounds, volatilized gaseous hazardous compounds may leak out.

By "outflow surface" is meant the surface from which liquid hazardous compounds flow or dissipate. Examples of outflow surfaces include floor surfaces, road surfaces, water surfaces, ground surfaces, and the like. The outflow surface may be flat or uneven. Also, the outflow surface may be a horizontal surface, an inclined surface having a gradient, or a vertical surface.

The thickness dimension of the stain diffusion suppression sheet 1 is preferably 0.5 mm or more and 6.0 mm or less, more preferably 1.0 mm or more and 5.5 mm or less, and still more preferably 1.5 mm or more and 5.5 mm or less. 0 mm or less. The pollution diffusion suppression sheet 1 is a flexible sheet. However, the degree of flexibility (degree of flexibility) is not particularly limited as long as it has flexibility. Also, the weight of the stain diffusion suppression sheet 1 is preferably 700 g/m ² or less, more preferably 600 g/m ² or less, and still more preferably 550 g/m ² or less from the viewpoint of portability.

The pollution diffusion suppression sheet 1 includes a liquid-retaining layer 2, an air-permeable waterproof layer 6, a gas-adsorbing layer 3, and a barrier layer 4, as shown in FIG. Contamination diffusion suppression sheet 1 is formed by laminating and integrating a liquid-retaining layer 2, an air-permeable waterproof layer 6, a gas-adsorbing layer 3, and a barrier layer 4 in this order.

(1.1) Liquid-retaining layer The liquid-retaining layer 2 is a layer that absorbs and retains liquid harmful compounds. One of the main surfaces of the liquid-retaining layer 2 according to the present embodiment serves as a surface facing the outflow surface (sometimes referred to as a "liquid-absorbing surface 7") during use. The liquid-retentive layer 2 has a water absorption capacity of 9 times or more and an oil absorption capacity of 9 times or more, and more preferably a water absorption capacity of 15 times or more and an oil absorption capacity of 9.5 times or more. More preferably, the water absorption capacity is 18 times or more and the oil absorption capacity is 9.9 times or more. Here, the term "absorption capacity" as used herein is a value indicating how many times the weight of the object (water or oil) the liquid-retaining layer 2 can absorb and retain before its own weight. Assuming that the self weight of the liquid-retaining layer 2 is G ₁ and the liquid-retaining layer 2 after water absorption is G ₂ , the absorbency A can be obtained by A=(G ₂ −G ₁ )/G ₁ . Although the upper limit of the absorption capacity is not particularly limited, for example, the absorption capacity of water is 20 times or less, and the absorption capacity of oil is 11 times or less.

The material of the liquid-retentive layer 2 is not particularly limited as long as both the water absorption capacity and the oil absorption capacity are 9 times or more, but for example, it is composed of a fiber assembly. A "fiber assembly" is formed by entangling and/or bonding fibers of at least one type in a crossed and/or overlapping state. Examples of fiber aggregates include woven fabrics, knitted fabrics, non-woven fabrics, and fiber aggregates made of composite materials composed of two or more of these. Among them, it is preferable to use a nonwoven fabric from the viewpoint of ease of handling.

Although there are no particular restrictions on the fibers that make up the fiber assembly, it is preferable that the fibers include absorbent fibers from the viewpoint of absorbency. Examples of absorbent fibers include Lanseal (registered trademark) and Bell Oasis (registered trademark), which are absorbent fibers having a multilayer structure including an inner layer and a hydrogel outer layer.

As an example of absorbent fibers, for example, highly absorbent fibers described in JP-A-54-138693 can be mentioned. This absorbent fiber has a multi-layer structure consisting of an inner layer composed of an acrylonitrile polymer and/or other polymer and an outer layer composed of a hydrophilic crosslinked polymer (sometimes referred to as a "hydrogel outer layer"). be. For example, when the inner layer portion of the absorbent fiber is made of an acrylonitrile polymer, the absorbent fiber is hydrolyzed by causing a specific alkali metal hydroxide aqueous solution to act on the fiber made of the acrylonitrile polymer to obtain only the outer layer portion of the fiber. is obtained by selectively hydrophilic cross-linking (hydrogelation).

Acrylonitrile-based polymer means a polymer containing acrylonitrile as a copolymer component, and is an acrylonitrile homopolymer, or a copolymer of acrylonitrile and one or more other ethylenically unsaturated compounds, Alternatively, a mixed polymer of acrylonitrile and other polymer may be used. Examples of other polymers include polyvinyl chloride-based, polyamide-based, polyolefin-based, polystyrene-based, polyvinyl alcohol-based, and cellulose-based polymers.

The average fiber diameter (diameter) of the absorbent fibers is preferably 5 µm or more and 50 µm or less, more preferably 10 µm or more and 40 µm or less, and still more preferably 20 µm or more and 30 µm or less. If the average fiber diameter is less than 5 μm, the mechanical strength is poor. On the other hand, if the average fiber diameter exceeds 50 μm, droplets of harmful compounds tend to remain on the object to be decontaminated.

The term "average fiber diameter" as used herein means the average value of the thicknesses of a plurality of fibers forming a fiber assembly. The average fiber diameter is measured by using a caliper to measure the diameter of the fibers forming the fiber assembly. 20 fibers out of a large number of fibers are randomly selected, the diameter of the fibers is measured, and the average value is taken as the average fiber diameter. For example, when the cross-sectional shape of the fiber is round, the diameter of each fiber may be the value measured with a vernier caliper. square, etc.), use the value of the diameter of a circle having an area equivalent to the cross-sectional area of the fiber.

In order to increase the contact area with the liquid, the cross-sectional shape of the fibers in the fiber assembly may be a fiber with a triangular, polygonal, or other complicated cross-section, or a fiber that is partly or wholly fibrillated. It is also possible to

The fiber assembly is not limited to the above-described absorbent fibers, but includes natural fibers such as cotton, hemp, wool, and silk; regenerated fibers such as rayon, polynosic, cupra, and leyocell; semi-synthetic fibers such as acetate and triacetate fibers. Polyamide fibers such as nylon 6, nylon 66, and aramid fibers; Polyester fibers such as polyethylene terephthalate fiber, polybutylene terephthalate fiber, polylactic acid fiber, and polyarylate; Polyacrylonitrile fiber, polyacrylonitrile-vinyl chloride copolymer fiber, modacrylic fiber Polyolefin fibers such as polyethylene fibers and polypropylene fibers; Polyvinyl alcohol fibers such as vinylon fibers and polyvinyl alcohol fibers; Polyvinyl chloride fibers such as polyvinyl chloride fibers, vinylidene fibers and polyclar fibers; Synthetic fiber; polyphenylene sulfide fiber; polybenzazole fiber (PBZ), polyparaphenylenebenzobisoxazole (PBO), polybenzimidazole (PBI) fiber, heterocyclic polymer fiber such as polyimide fiber; polycarbonate fiber; polysulfone fiber; polyethylene Polyether fibers such as oxide fibers and polypropylene oxide fibers; These fibers may be used in combination.

The mass of the liquid-retaining layer 2 is preferably 50 g/m ² or more and 800 g/m ² or less, more preferably 100 g/m ² or more and 600 g/m ² or less, and still more preferably 150 g/m ² or more. 400 g/m ² or less. If the mass of the liquid-retaining layer 2 is less than 50 g/m ² , the liquid-retaining property is lowered, making it difficult to obtain a satisfactory decontamination performance for harmful compounds. On the other hand, if the mass of the liquid-retaining layer 2 exceeds 800 g/m ² , the flexibility and ease of handling during use may be impaired.

The thickness dimension of the liquid-retaining layer 2 is preferably 1 mm or more and 10 mm or less, more preferably 1.5 mm or more and 8.0 mm or less, and still more preferably 2.0 mm or more and 6.0 mm or less. If the thickness dimension of the liquid-retaining layer 2 is less than 1 mm, it may not be possible to obtain adequate mechanical strength. On the other hand, if the thickness dimension of the liquid-retaining layer 2 exceeds 10 mm, there is a possibility that ease of handling during use will be impaired.

(1.2) Air-permeable waterproof layer The air-permeable waterproof layer 6 prevents passage of liquid, but allows passage of gas. As shown in FIG. 1, the air-permeable waterproof layer 6 is provided between the liquid-retaining layer 2 and the gas-adsorbing layer 3, and prevents passage of the liquid component of the harmful compound absorbed by the liquid-retaining layer 2. Gaseous components are allowed to pass through. Gaseous harmful compounds that have passed through the breathable waterproof layer 6 are adsorbed by the gas adsorption layer 3 .

Examples of the air-permeable waterproof layer 6 include sheet materials such as low-density polyethylene (LLDPE; Linear Low Density Polyethylene, LDPE; Low Density Polyethylene) film, non-axially oriented polypropylene (CPP; Cast PolyPolypropylene) film, and porous film. . Examples of porous film materials include polyolefin resins (e.g., polyethylene, polypropylene, etc.), expanded polytetrafluoroethylene (ePTFE), polyethersulfone (PES; PolyEtherSulfone) resin, and polyvinylidene fluoride (PVDF; PolyVinylidene DiFluoride). Resin, polyurethane (PU; Polyurethane) resin, polyamide-imide (PAI; Polyamide-imide) resin, polyimide (PI; Polyimide) resin, and the like can be mentioned.

Although the thickness dimension of the breathable waterproof layer 6 is not particularly limited, it is preferably 10 μm or more and 80 μm or less, more preferably 20 μm or more and 70 μm or less, and still more preferably 15 μm or more and 35 μm or less. If the thickness dimension is less than 10 μm, the strength is low, and there is a possibility that external force will be applied during wiping and the film will break. On the other hand, if the thickness dimension exceeds 80 μm, the flexibility of the stain diffusion suppression sheet 1 may be impaired. The barrier layer 4 is laminated on the gas adsorption layer 3 by, for example, adhesion, sewing, or welding.

(1.3) Gas adsorption layer The gas adsorption layer 3 adsorbs gaseous harmful compounds. As shown in FIG. 1, the gas adsorption layer 3 is laminated on the surface of the liquid-retaining layer 2 opposite to the liquid-absorbing surface 7 in the thickness direction. As used herein, the term "lamination" means that multiple layers are stacked in the thickness direction. Here, the gas adsorption layer 3 and the liquid-retaining layer 2 are directly stacked, but another layer may be interposed between the gas-adsorption layer 3 and the liquid-retaining layer 2. Even in this case, It is assumed that the gas adsorption layer 3 is laminated on the liquid-retaining layer 2 .

The gas adsorption layer 3 is composed of a large number of gas adsorbents dispersed in a binder. The gas adsorbent is not particularly limited, and examples thereof include activated carbon, carbon black, silica gel, zeolite adsorbent, silicon carbide, activated alumina, and ion exchange resin. Among them, activated carbon is preferable because it can handle a wide range of gases. Examples of activated carbon include granular activated carbon, fibrous activated carbon, and composite materials thereof.

Granular activated carbon is, for example, granular activated carbon obtained by subjecting plant-based carbides such as coconut shells, sawdust, and bamboo, and mineral-based carbides such as coal and petroleum (pitch) to an activation reaction by gas activation or chemical activation. is. Granular activated carbon includes, for example, crushed coal, granular coal, molded coal, and the like. As used herein, "granular activated carbon" includes powdered activated carbon.

The BET specific surface area of the granular activated carbon is preferably 500 m ² /g or more and 2000 m ² /g or less, more preferably 600 m ² /g or more and 1800 m ² /g or less. If the BET specific surface area is less than 500 m ² /g, a large amount of activated carbon is required in order to obtain a sufficient amount of adsorption for gaseous compounds, and the material becomes heavy and flexibility may be impaired. On the other hand, if the BET specific surface area exceeds 2000 m ² /g, the gas adsorbent may become brittle.

The average particle size of granular activated carbon is preferably 50 µm or more, more preferably 100 µm or more. Also, the average particle size of the granular activated carbon is preferably 3000 μm or less, more preferably 2000 μm or less.

The "average particle size" referred to here is the particle size of granular activated carbon measured using an optical microscope. Optional 100 activated carbons out of a large number of activated carbons are extracted, the particle size is measured, the measured particle sizes are arithmetically averaged, and this average value is taken as the average particle size of the granular activated carbon.

The basis weight of the gas adsorption layer 3 containing granular activated carbon is preferably 50 g/m ² or more and 250 g/m ² or less, more preferably 70 g/m ² or more and 200 g/m ² or less. If the basis weight is less than 50, there is concern that the adsorption capacity will be small and the gaseous compound scattering suppression performance will be low. On the other hand, if the basis weight exceeds 250 g/m ² , the flexibility of the material may be impaired.

When fibrous activated carbon is used as the gas adsorbent, the BET specific surface area is preferably 700 m ² /g or more and 3000 m ² /g or less, more preferably 1000 m ² /g or more and 2500 m ² /g or less. If the BET specific surface area is less than 700 m ² /g, a large amount of activated carbon is required in order to obtain a sufficient adsorption amount for gaseous compounds, and the material becomes heavy, possibly impairing flexibility. On the other hand, if the BET specific surface area exceeds 3000 m ² /g, the gas adsorbent may become brittle.

The basis weight (absolute dry weight) of the gas adsorption layer 3 containing fibrous activated carbon is preferably 50 g/m ² or more and 250 g/m ² or less, more preferably 70 g/m ² or more and 200 g/m ² or less. If the basis weight is less than 50 g/m ² , the capacity of the adsorbable gas may be small, and the gaseous compound scattering suppression performance may be lowered. On the other hand, if the basis weight exceeds 250 g/m ² , the flexibility of the material may be impaired.

The thickness of the fibrous activated carbon is, for example, preferably 0.1 mm or more and 3.0 mm or less, more preferably 0.5 mm or more and 2.0 mm or less, and even more preferably 0.7 mm or more and 1.5 mm or less. If the thickness of the fibrous activated carbon is less than 0.1 mm, the adsorption amount of gaseous harmful compounds may decrease. On the other hand, if the thickness dimension of the fibrous activated carbon exceeds 3.0 mm, the ease of handling during use may be impaired.

Raw materials for fibrous activated carbon include, for example, natural cellulose fibers (such as cotton, hemp, etc.), rayon, polynosic, regenerated cellulose fibers, polyvinyl alcohol fibers, acrylic fibers, aromatic polyamide fibers, lignin fibers, phenolic fibers, and petroleum. Synthetic fibers such as pitch fibers are included. Among these, regenerated cellulose fibers, phenolic fibers, and acrylic fibers are preferable from the viewpoint of strength and adsorption performance.

The fibrous activated carbon can be obtained, for example, by adding an appropriate flameproofing agent to a fabric obtained by weaving, knitting, or making a non-woven fabric using the short fibers or long fibers of the above-mentioned raw material fibers, and then heating it at a temperature of 450 ° C. or less. , followed by carbonization activation at a temperature of 500°C or higher and 1000°C or lower.

The gas adsorption layer 3 preferably has a form of woven fabric, knitted fabric, non-woven fabric, or felt. Of these, the woven or knitted fabric is more preferable from the viewpoints of air permeability, ease of lamination, flexibility, and the like.

The method of laminating the gas adsorption layer 3 and the liquid-retaining layer 2 is not particularly limited.

(1.4) Barrier Layer The barrier layer 4 prevents passage of gases and liquids. As shown in FIG. 1 , the barrier layer 4 is laminated on the opposite side of the gas adsorption layer 3 to the liquid-retaining layer 2 in the thickness direction of the contamination diffusion suppression sheet 1 . Moreover, the barrier layer 4 according to the present embodiment also prevents passage of liquid harmful compounds. Therefore, even if a harmful compound passes through the liquid-retaining layer 2 and the gas adsorption layer 3, it is possible to prevent the harmful compound from flowing toward the operator.

The barrier layer 4 is composed of a sheet material such as an impermeable film. The barrier layer 4 is not particularly limited. resin, polyethylene terephthalate, polyvinyl acetate resin, polyamide resin, urethane resin, cellulose resin, low density polyethylene (LLDPE; Linear Low Density Polyethylene, LDPE; Low Density Polyethylene) film, and the like. The barrier layer 4 according to this embodiment is composed of an LLDPE film. The cost can be reduced by forming the barrier layer 4 and the air-permeable waterproof layer 6 from the same material to use common materials.

Although the thickness dimension of the barrier layer 4 is not particularly limited, it is preferably 10 μm or more and 80 μm or less, more preferably 15 μm or more and 35 μm or less, and still more preferably 20 μm or more and 30 μm or less. If the thickness dimension is less than 10 μm, the strength is low, and there is a possibility that external force will be applied during wiping and the film will break. On the other hand, if the thickness dimension exceeds 80 μm, the flexibility of the stain diffusion suppression sheet 1 may be impaired. The barrier layer 4 is laminated on the gas adsorption layer 3 by, for example, adhesion, sewing, or welding.

<effect>
As described above, the pollution diffusion suppression sheet 1 according to the present embodiment includes the breathable waterproof layer 6 between the liquid-retaining layer 2 and the gas-adsorbing layer 3, so that liquid harmful compounds absorbed by the liquid-retaining layer 2 are As a result, it is possible to prevent the gas adsorption layer 3 from getting wet and lowering its function while adsorbing gaseous harmful compounds volatilized from the absorbed liquid. As a result, it is possible to suppress the spread of the liquid harmful compound that has flowed out to the outflow surface by absorbing it, and it is possible to suppress the leakage of the gaseous harmful compound.

In addition, since the pollution diffusion suppression sheet 1 according to the present embodiment further includes a barrier layer 4 provided on the opposite side of the gas adsorption layer 3 from the liquid retaining layer 2 to prevent passage of the gas, the absorbed liquid Hazardous compounds and gaseous hazardous compounds can be prevented from leaking to the operator side.

In addition, in the pollution diffusion suppression sheet 1 according to the present embodiment, the air permeable waterproof layer 6 has a thickness of 10 μm or more and 80 μm or less, so that the pollution diffusion suppression sheet 1 can maintain its flexibility.

In addition, in the pollution diffusion suppression sheet 1 according to the present embodiment, the absorption capacity of water and the absorption capacity of oil in the liquid-retaining layer 2 are respectively 9 times or more of the own weight of the liquid-retaining layer 2, so that a sufficient amount of liquid of harmful compounds can be absorbed.

Further, in the stain diffusion suppression sheet 1 according to the present embodiment, the liquid-retaining layer 2 is composed of a fiber assembly containing absorbent fibers. The absorbent fibers have a multi-layered structure including an inner layer and a hydrogel outer layer. Therefore, the liquid-retaining layer 2 can absorb and retain a sufficient amount of the liquid harmful compound.

Further, the pollution diffusion suppression sheet 1 according to the present embodiment has good manufacturability because the gas adsorption layer 3 contains granular activated carbon, fibrous activated carbon, or a composite material thereof.

(2) Embodiment 2
In the pollution diffusion suppression sheet 1 according to Embodiment 2, as shown in FIG. It is different from the contamination diffusion suppression sheet 1 according to the first embodiment in that Concerning the pollution diffusion suppression sheet 1 according to Embodiment 2, the same components as those of the pollution diffusion suppression sheet 1 according to Embodiment 1 are denoted by the same reference numerals, and description thereof is omitted.

The liquid absorbing layer 5 absorbs liquid harmful compounds. As shown in FIG. 2, the liquid-absorbing layer 5 is laminated on the side opposite to the gas-adsorbing layer 3 with respect to the liquid-retaining layer 2 . The liquid-absorbing layer 5 is composed of a fiber aggregate, and the fibers of the fiber aggregate have a smaller average fiber diameter than the fibers of the fiber aggregate forming the liquid-retaining layer 2 . Therefore, compared to the liquid-retaining layer 2, the liquid-absorbing layer 5 is more likely to deform following the shape of the outflow surface. Therefore, according to the pollution diffusion suppression sheet 1 according to the present embodiment, even if the outflow surface is an uneven surface, it is possible to prevent the formation of a gap between the pollution diffusion suppression sheet 1 and the outflow surface.

The fiber assembly constituting the liquid-absorbing layer 5 is not particularly limited as long as the average fiber diameter of the fibers is smaller than that of the liquid-retaining layer 2; Examples thereof include a fiber assembly made of a composite material composed of two or more kinds. Among them, it is preferable to use a nonwoven fabric from the viewpoint of ease of handling.

Although there are no particular restrictions on the fibers that make up the fiber assembly, examples thereof include nylon fibers and split acrylic fibers. When a nonwoven fabric is used as the fiber assembly, for example, a meltblown nonwoven fabric using nylon fibers, a nonwoven fabric using split acrylic fibers, or the like is preferably used. When a melt-blown nonwoven fabric using nylon fibers is used for the fiber assembly, the absorbent layer main body 51 should be covered with a nonwoven fabric (cover layer 52) using PET fibers from the viewpoint of suppressing fluffing and reinforcing mechanical strength. is preferred.

The average fiber diameter (diameter) of the absorbent fibers constituting the absorbent layer 5 is preferably 0.05 μm or more and 5.0 μm or less, more preferably 0.15 μm or more and 4.5 μm or less, and still more preferably It is 0.2 or more and 3.5 μm or less. If the average fiber diameter is less than 0.05 μm, fluffing tends to occur and the mechanical strength is poor. On the other hand, if the average fiber diameter exceeds 5.0 μm, it is difficult for capillary action to occur between fibers, and appropriate liquid absorption performance may not be obtained.

The liquid-absorbing layer 5 transfers the absorbed liquid to the liquid-retaining layer 2 and is configured to suppress diffusion at this time. If the average fiber diameter is simply smaller than the average fiber diameter of the fibers of the fiber assembly that constitutes the liquid-retaining layer 2, the absorbed liquid and gas tend to spread in the plane direction of the layer, and the liquid and gas diffuse contamination. This is because it may leak from the end of the suppression sheet 1 .

The liquid-absorbing layer 5 according to this embodiment is integrated with the liquid-retaining layer 2 by needle punching in order to suppress diffusion. The fibers of the liquid absorbing layer 5 and the liquid retaining layer 2 integrated by needle punching are entangled and/or bonded through the through-holes in an overlapping state. The harmful compound absorbed by the liquid-absorbing layer 5 can move to the liquid-retaining layer 2 through the through-holes without spreading along the surface direction.

The mass of the absorbent layer 5 is preferably 10 g/m ² or more and 50 g/m ² or less, more preferably 11 g/m ² or more and 35 g/m ² or less, still more preferably 12 g/m ² or more and 20 g/m 2 or more. ^m2 or less. If the mass of the liquid-retaining layer 2 is less than 10 g/m ² , the liquid absorbability is lowered, making it difficult to obtain a satisfactory absorbency of harmful compounds. On the other hand, if the mass of the liquid-retaining layer 2 exceeds 50 g/m ² , the flexibility and ease of handling during use may be impaired.

The thickness dimension of the absorbent layer 5 is preferably 0.05 mm or more and 1.0 mm or less, more preferably 0.08 mm or more and 0.5 mm or less, and still more preferably 0.1 mm or more and 0.3 mm or less. be. If the thickness dimension of the liquid absorbing layer 5 is less than 0.05 mm, it may not be possible to obtain adequate mechanical strength. On the other hand, if the thickness dimension of the absorbent layer 5 exceeds 1.0 mm, the ease of handling during use may be impaired.

Even with the pollution diffusion suppression sheet 1 having such a configuration, it is possible to absorb a sufficient amount of liquid hazardous compounds and to suppress leakage of gaseous hazardous compounds. In addition, even if the surface from which the liquid flows is uneven, the liquid harmful compound can be absorbed appropriately.

<Modification>
The above embodiment is but one of the various embodiments of the present invention. The embodiment can be modified in various ways according to the design, etc., as long as the object of the present invention can be achieved. Modifications of the above embodiment will be described below.

In the pollution diffusion prevention sheet 1 according to the present invention, at least one of the plurality of layers constituting the pollution diffusion prevention sheet 1 according to Embodiments 1 and 2 contains a decomposing agent that decomposes harmful substances and/or bacteria. An antibacterial agent that inhibits propagation may be included. By including a decomposing agent and/or an antibacterial agent in either layer, the risk of secondary contamination when the contamination diffusion prevention sheet 1 is used can be reduced.

Examples of decomposing agents include metals and metal oxides, and specific examples include gold, silver, copper, platinum, palladium, iridium, tin, antimony, bismuth, zinc, silver oxide, magnesium oxide, oxide Calcium, nickel oxide, manganese oxide, copper oxide, selenium oxide, zinc oxide, iron oxide, aluminum oxide, tungsten oxide, titanium oxide and the like. Among them, metal oxides are relatively inexpensive and stable, and are suitable for use.

Examples of antibacterial agents include biguanide antibacterial agents, inorganic antibacterial agents (e.g., metals, metal oxides, etc.), organic antibacterial agents (e.g., phenol, quaternary ammonium salt, pyridine, iodine, etc.). , imidazole-based, thiazole-based, isothiazolone-based, chitosan-based, pyrithione-based, etc.).

Known methods such as padding, impregnation, spraying, coating, and kneading during spinning can be used to incorporate the decomposing agent and/or antibacterial agent into the layer.

<Example>
EXAMPLES The present invention will be described in more detail below with reference to examples. However, the stain diffusion suppression sheet according to the present invention is not limited to the following examples.

(1) Example 1
As the pollution diffusion suppression sheet according to Example 1, the liquid-retaining layer, the gas-adsorbing layer, and the barrier layer were composed of the following materials. Regarding the stain diffusion suppression sheet according to Example 1, the basis weight, thickness, bulk density and average fiber diameter were measured by the following methods. Then, using the contamination diffusion suppression sheet according to Example 1, the amount of liquid retained, the absorption capacity, and the absorption rate of the uneven surface were measured, and tests (leakage test, sealing test) for confirming gas adsorption were performed. .
・ Liquid-retentive layer: Fiber sheet containing Lanseal (registered trademark) (Product number: TB403-1, Japan Exlan Kogyo Co., Ltd.) Average fiber diameter: 25.4 μm Absorption factor: Oil: 10 times Water: 19 times ・ Breathable waterproof layer: LLDPE film 30 µm
Gas adsorption layer: EVA resin (PR 2030H manufactured by Tokyo Ink Co., Ltd.) was used as a binder, and granular activated carbon made of coal (activated carbon "Granular Shirasagi W5C20/42" manufactured by Osaka Gas Chemicals Co., Ltd.) was mixed. Weight: 130g/ ^m2
・Barrier layer: LLDPE film 30μm

(1.1) Measurement method/weight: Measured according to JIS L 1096.8.3.
- Thickness dimension: Measured by a method based on JIS L 1096.8.4. All materials were measured with a load of 7 gf/cm ² applied.
- Bulk density: Calculated by (basis weight)/(thickness dimension).
· Average fiber diameter: The surface of the fiber assembly to be measured was observed with an electron microscope, the fiber diameters were measured at 20 points, and the average diameter was calculated.
Absorbency on uneven surface: Fix the test piece (4.0 cm x 2.5 cm) on the sample fixing plate (rubber sheet of 2.5 cm x 2.5 cm x 1.0 cm thick) with tape, etc. so that the liquid absorption surface faces outward. do. The weight of a vinyl chloride mat with an uneven surface (surface shape with continuous square pyramids with a base of 5.0 mm and a height of 0.6 mm, dimensions of 2.5 cm x 2.5 cm) was measured (X mg), and then the test solution (dipropyl phthalate) was applied to the uneven surface. Measure the weight after dropping 10 μL (Ymg). Place the liquid absorption surface of the test piece fixed on the sample fixing plate against the test solution, and slowly place a weight (0.5 kg) on the sample fixing plate. After 20 seconds have passed, the test piece fixed on the sample fixing plate is removed, and the weight of the vinyl chloride mat is measured (Z mg). The uneven surface liquid absorption % is calculated by the following formula. {(YX) - (ZX)}/(YX) x 100 Liquid holding capacity: A 5 x 5 cm test piece is immersed in pure water or sewing machine oil (VG10) for 5 minutes, then pulled out, After hanging for 6 minutes with pure water and 10 minutes with sewing machine oil (VG10), the weight is measured (G2), and the amount of liquid absorbed by the test piece is calculated from the dry weight (G1) and wet weight (G2) of the test piece. (G2-G1) is calculated and expressed in weight per m ² (g/m ² ).
・Absorption capacity: Absorption capacity A of all layers is obtained from A=(G2-G1)/G1 after measuring the retained liquid amount (G2-G1) in all layers. Similarly, for the liquid-retaining layer, after measuring the amount of retained liquid in a single liquid-retaining layer, the absorption capacity is determined.

For the leak test, the test environment was set at 25°C, and the sheet according to each example was cut into 10 cm ^squares to prepare test pieces. A placebo (3-methoxybutyl acetate) was added dropwise. Place this on the inner bottom surface of a desiccator (12 L) as shown in Fig. 3 with the liquid absorption side down, put a weight (10 g / piece) on the four corners of the test piece and seal it, leak at predetermined time intervals Gas concentrations were measured using gas chromatography.

As a sealing test, the test environment was set to 25°C, and the sheet according to ^each example was cut into a circular shape with a diameter of 9.6 cm to prepare a test piece. (300 μL) placebo (3-methoxybutyl acetate) was added dropwise. Using a glass cell equipped with a first container 81 having a flange and a second container 82 having a flange as shown in FIG. (the space SP1 in the first container 81), and the opposite surface thereof was directed to the downstream space (the lower space SP2), sandwiched between the flanges of the containers 81 and 82 and sealed. Gas permeation concentrations in the upstream space SP1 and the downstream space SP2 were measured at predetermined time intervals using gas chromatography.

The measurement results are shown in Table 1, the leakage test results are shown in FIG. 5, and the sealing test results are shown in FIGS. In the graph, Example 1 is abbreviated as "actual 1" and comparative example 1 is abbreviated as "ratio 1".

(2) Comparative Example 1
As the pollution diffusion suppression sheet according to Comparative Example 1, the liquid-retaining layer, the gas-adsorbing layer, and the barrier layer were composed of the following materials. Regarding the stain diffusion suppression sheet according to Comparative Example 1, the basis weight, thickness dimension, bulk density and average fiber diameter were measured by the method described in "(1.1) Measurement method". Then, using the contamination diffusion suppression sheet according to Comparative Example 1, the liquid retention amount, absorption capacity, and absorption rate of the uneven surface were measured, and a test (sealing test) for confirming gas adsorption was performed.
・Liquid retention layer: Fiber sheet containing Lanseal (registered trademark) (product number: TB403-1, manufactured by Nihon Exlan Kogyo Co., Ltd.) Average fiber diameter: 25.4 μm Absorption factor: Oil: 10 times Water: 19 times ・Gas adsorption layer: EVA resin (PR 2030H manufactured by Tokyo Ink Co., Ltd.) as a binder was mixed with granular activated carbon made of coal (activated carbon "Granular Shirasagi W5C20/42" manufactured by Osaka Gas Chemicals Co., Ltd.). Weight: 130g/ ^m2
・Barrier layer: CPP film 25μm

The measurement results are shown in Table 1, and the sealing test results are shown in FIGS.

(3) Comparative Example 2
As a sheet according to Comparative Example 2, a blanket obtained by mixing wool and polyethylene was used. The basis weight, thickness, bulk density and average fiber diameter of the sheet according to Comparative Example 2 were measured by the methods described in "(1.1) Measurement method". Then, using the sheet according to Comparative Example 2, the liquid holding capacity, absorption capacity, and absorption rate of the uneven surface were measured, and a test (sealing test) for confirming gas adsorption was performed.

The measurement results are shown in Table 1, and the sealing test results are shown in FIGS.

(4) Comparative Example 3
As a sheet according to Comparative Example 3, a vinyl chloride (PVC) sheet was used. The basis weight, thickness dimension, and bulk density of the sheet according to Comparative Example 3 were measured by the methods described in "(1.1) Measurement method". Then, using the sheet according to Comparative Example 3, a test (leakage test) for confirming the gas adsorptivity was performed.

The measurement results are shown in Table 1, and the leak test results are shown in FIGS.

(5) Comparative Example 4
As a sheet according to Comparative Example 4, a sheet composed of a liquid absorbing layer, a liquid retaining layer and a barrier layer was produced. The liquid-absorbing layer, liquid-retaining layer and barrier layer were composed of the following materials. The basis weight, thickness, bulk density and average fiber diameter of the sheet according to Comparative Example 4 were measured by the methods described in "(1.1) Measurement method". Then, using the sheet according to Comparative Example 4, the liquid holding capacity, absorption capacity, and absorption rate of the uneven surface were measured, and tests (leakage test and sealing test) for confirming gas adsorption were performed.
・Absorbent layer: Melt-blown non-woven fabric using polypropylene fibers Average fiber diameter: 3.14μm ・Liquid-retentive layer: Perlite Weight per unit area: 160g/m ² to 200 g/m ² Absorption ratio: Oil: 6 times Water: 8 times ・Gas adsorption Layer: None Barrier layer: PP film 40 μm

The measurement results are shown in Table 1, the leakage test results are shown in FIG. 5, and the sealing test results are shown in FIGS.

(6) Comparative Example 5
As a sheet according to Comparative Example 5, a sheet composed of a liquid-retaining layer, a gas-adsorbing layer and a barrier layer was produced. The liquid-retaining layer, gas-adsorbing layer and barrier layer were composed of the following materials. For the sheet according to Comparative Example 5, the basis weight, thickness dimension, bulk density and average fiber diameter were measured by the method described in "(1.1) Measuring method". Then, using the sheet according to Comparative Example 5, the liquid holding capacity, absorption capacity, and absorption rate of the uneven surface were measured, and tests (leakage test and sealing test) for confirming gas adsorption were performed.・Liquid retention layer: Non-woven fabric using polypropylene fiber (P030LW-00X manufactured by Tapyrus Co., Ltd.) Average fiber diameter: 5.2 μm Metsuke: 300 g/m ² Absorption capacity: Oil: 7 times Water: 0.1 time ・Gas adsorption layer: EVA resin (PR 2030H manufactured by Tokyo Ink Co., Ltd.) as a binder was mixed with granular activated carbon made of coal (activated carbon "Granular Shirasagi W5C20/42" manufactured by Osaka Gas Chemicals Co., Ltd.). Weight: 130g/ ^m2
・Barrier layer: CPP film 25μm

The measurement results are shown in Table 1, the leakage test results are shown in FIG. 5, and the sealing test results are shown in FIGS.

As shown in FIG. 5, when Example 1 is compared with Comparative Examples 3 and 4 in the leak test, the leaked gas concentration after 90 minutes has elapsed is approximately 0 ppm or less in Example 1, whereas In 3 and 4, the leakage gas concentration exceeds 250ppm. As can be seen from this, it was found that the presence of the gas adsorption layer can significantly suppress the concentration of leaked gas.

As shown in FIG. 6(A), in the sealing test, when comparing Example 1 with Comparative Examples 1, 2, 4, and 5, the downstream gas concentration after 1300 minutes has passed is almost 0 ppm in Example 1. On the other hand, in Comparative Examples 1, 2, 4 and 5, it is 50 ppm or more. As can be seen from this, in Example 1, it was found that the passage of gas can be effectively suppressed.

Also, as shown in FIG. 6(B), in the closed test, when comparing Example 1 with Comparative Examples 2, 4 and 5, the upstream gas concentration after 1300 minutes has elapsed is less than 200 ppm in Example 1. On the other hand, in Comparative Examples 2, 4 and 5, it exceeds 500 ppm. As can be seen from this, in Example 1, it was found that the gas on the upstream side can be adsorbed.

Also, as shown in FIG. 6(B), when Example 1 and Comparative Example 1 are compared in the sealing test, the upstream gas concentration after 1440 minutes has passed is about 130 ppm in Example 1. In Comparative Example 1, it is about 250 ppm. As can be seen from this, it was found that the air-permeable and waterproof layer provided higher gas adsorption performance after a long period of time.

As shown in Table 1, when Example 1 and Comparative Example 5 are compared with respect to the retained liquid amount, in Example 1, oil is 1100 g/m ² and water is 2100 g/m ² , Comparative Example 5 contains 300 g/m ² of oil and 10 g/m ² of water. As can be seen from this, in Example 1, even if the basis weight was about the same, it was found that the retention amounts of both oil and water were high.

REFERENCE SIGNS LIST 1 pollution diffusion suppression sheet 2 liquid-retaining layer 3 gas adsorption layer 4 barrier layer 5 liquid-absorbing layer 51 liquid-absorbing layer main body 52 cover layer 6 ventilation waterproof layer

Claims (6)

a liquid-retaining layer that absorbs and retains liquid harmful compounds;
a gas adsorption layer that adsorbs gaseous harmful compounds;
a breathable waterproof layer that is provided between the liquid-retaining layer and the gas-adsorbing layer and that prevents passage of liquid and allows passage of gas;
comprising a
Contamination diffusion suppression sheet. Further comprising a barrier layer provided on the opposite side of the gas adsorption layer to the liquid-retaining layer in the thickness direction of the pollution diffusion suppression sheet to prevent the passage of gas,
The pollution diffusion suppression sheet according to claim 1. The thickness dimension of the breathable waterproof layer is 10 μm or more and 80 μm or less.
The pollution diffusion suppression sheet according to claim 1 or 2. The water absorption capacity and the oil absorption capacity of the liquid-retaining layer are respectively 9 times or more the weight of the liquid-retaining layer.
The stain diffusion suppression sheet according to any one of claims 1 to 3. The liquid-retaining layer is composed of a fiber assembly containing absorbent fibers,
The absorbent fiber has a multi-layered structure including an inner layer and a hydrogel outer layer outside thereof,
The pollution diffusion suppression sheet according to claim 4. The gas adsorption layer contains granular activated carbon, fibrous activated carbon, or a composite material thereof,
The stain diffusion suppression sheet according to any one of claims 1 to 5.

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