JP2010094126A - Water-retaining material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide water-retaining material enabling plant roots to deeply and broadly extend without inhibiting growth of the plant roots, excellent in vegetation effect, designed so that water-absorbing resin is hardly detached from a sheet part to maintain the shape of the sheet part so as to keep the water-absorbing properties of the material, excellent in durability because of inhibiting expansion of soil due to freeze, and enabling application to a slanted ground or a rising surface such as a slope surface or a wall surface as well as horizontal utilization. <P>SOLUTION: The water-retaining material includes: (a) a sheet part obtained by integrating fibrous water-absorptive resin and base material fibers; and (b) at least one communicating part which is formed on the sheet part and through which the plant roots pass. The communicating part has continuous spaces and/or a through-hole passing through in the direction of the thickness of the sheet part. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a water retaining material embedded in soil.

Plants will dry and die if the drying period continues. Therefore, a water retaining material is known that is buried in the soil, absorbs rainfall during raining and irrigation, and supplies the absorbed moisture to the soil when the soil is dry, thereby preventing the plants from drying and dying. Yes.
As this conventional technique, (Patent Document 1) states that “a superabsorbent resin is provided in a woven fabric structure in a dry state with a space provided in the texture, and the swollen part of the superabsorbent resin is absorbed in the space. A highly water-absorbent woven fabric is disclosed.
(Patent Document 2) states that “it is formed from a water-absorbing nonwoven fabric layer composed of water-absorbing fibers obtained using a thermoplastic water-absorbing resin copolymerized with polyalkylene glycol, and a nonwoven fabric layer composed of thermoplastic fibers. A water-absorbent non-woven fabric laminate comprising 1 to 99% by weight of the water-absorbing fibers with respect to the total weight of the laminate is disclosed.

Japanese Patent No. 3488538 JP 2006-299425 A

However, the above conventional techniques have the following problems.
(1) The superabsorbent woven fabric disclosed in (Patent Document 1) or the water-absorbent non-woven fabric laminate disclosed in (Patent Document 2) is embedded in soil, and plant seedlings are planted or seeded thereon. The water-absorbing nonwoven fabric layer of the superabsorbent fabric and the water-absorbent nonwoven fabric layer (hereinafter referred to as the water-absorbent resin) form a water-retaining layer in the soil, and the plants dry and die. Can be prevented. The higher the density of the water absorbent resin in the super absorbent fabric, etc., the higher the water retention performance. However, when the density of the water-absorbent resin is high, it is difficult for the plant roots to penetrate the superabsorbent woven fabric or the water-absorbent nonwoven fabric laminate and to extend downward, so it is difficult for the plant to stretch the roots deeply and widely. It had the problem that. When root growth was hindered, the growth of ground foliage was also hindered, making it difficult to plant trees.
(2) The water-absorbing resin has a problem that the water-absorbing property is lowered at an early stage when irradiated with sunlight or ultraviolet rays. Until now, since it was thought that ultraviolet rays would not permeate through soil, it was thought that the water retaining material used by being embedded in soil did not need to consider the influence of ultraviolet rays and sunlight. However, it was found that when the water retaining material is buried in a relatively shallow position of the soil, it is easily affected by ultraviolet rays and the like irradiated from the ground surface. For this reason, after being embedded in the soil, there was a problem that the water absorption of the water absorbent resin was lowered early due to the influence of ultraviolet rays and sunlight, and the long-life property was lacking.
(3) When the superabsorbent woven fabric disclosed in (Patent Document 1) and the superabsorbent nonwoven fabric laminate disclosed in (Patent Document 2) come into contact with contaminated water, the contaminants become superabsorbent woven fabric or superabsorbent nonwoven fabric laminate. It is absorbed into the space inside the body. The space inside the superabsorbent woven fabric and the water absorbent non-woven fabric laminate is provided to absorb the increased volume of the water-absorbent resin swelled, but the contaminants are absorbed into the interior space. When the contaminants are clogged, the water-absorbent resin whose volume has been increased due to swelling protrudes from the gaps between the fibers of the highly water-absorbent woven fabric or water-absorbent nonwoven fabric laminate, and repeats shrinkage due to drying and swelling due to water absorption. It has a problem that the water-soluble resin easily falls off, and the water absorption of the superabsorbent woven fabric or the superabsorbent nonwoven fabric is lowered early.
(4) The superabsorbent woven fabric disclosed in (Patent Document 1) and the water-absorbent nonwoven fabric laminate disclosed in (Patent Document 2) have poor formability when the water-absorbent resin swells, and the vertical plane / method There was a problem that it was difficult to use on surfaces and slopes.

  The present invention solves the above-mentioned conventional problems, can spread the roots deeply and broadly without hindering the growth of the roots of the plant, is excellent in vegetation effect, and further, the water-absorbent resin is difficult to fall off from the sheet portion, for a long time The shape of the seat is maintained, the water absorption is maintained, and the soil expansion due to freezing is suppressed, so the durability is excellent, and in addition to the horizontal use, it can be used on slopes and wall surfaces such as slopes and elevations. An object is to provide a water retaining material that can be applied.

In order to solve the above conventional problems, the water retention material of the present invention has the following configuration.
The water-retaining material according to claim 1 of the present invention includes (a) a sheet portion in which a fibrous water-absorbing resin and base fiber are integrated, and (b) a plant root passes through the sheet portion. At least one communicating portion formed, and the communicating portion is a continuous gap and / or a through hole penetrating in the thickness direction of the sheet portion.
With this configuration, the following effects can be obtained.
(1) The plant is replenished with moisture from the sheet part, and further, the roots can be stretched deeply and deeply through the communication part formed in the sheet part, so that the growth of the foliage on the ground is also prevented without hindering the root growth. The vegetation effect can be enhanced without being hindered.
(2) Since the fibrous water-absorbing resin is integrated with the base fiber to form the sheet portion, the water-absorbing resin is difficult to drop off from the sheet portion, so that the shape of the sheet portion is maintained for a long period of time. Sex is maintained. Furthermore, since the water-absorbent resin does not freeze up to about -20 degrees even when it absorbs water, the seat portion is kept cushioned even in cold regions, so that the expansion of the soil due to freezing is suppressed, and the plant strain is lifted. Prevents roots from being damaged or draining.
(3) By adjusting the density between fibers, continuous voids can be formed as communication parts, and the roots of the plants extend through the continuous voids and eventually pass through the sheet part to directly root into the soil. Can be stretched and has excellent vegetation effect. Moreover, since an air layer is formed, it has an excellent root rot prevention effect.
(4) Since the communicating part can be formed as a through-hole penetrating in the thickness direction of the sheet, the root of the plant passes through the through-hole and eventually passes through the sheet part, so that the root can be directly rooted in the soil. Excellent effect.
(5) The base fiber can surround the periphery of the water-absorbent resin, and volume expansion at the time of water absorption of the water-absorbent resin is generated only in the space between the water-absorbent resin and the base fiber, thereby The volume expansion as a whole can be suppressed, and the formability is excellent.

  Here, the water-absorbing resin can be used without particular limitation as long as it can be formed in a fibrous form. For example, cellulose / acrylonitrile polymer, acrylic acid / vinyl alcohol copolymer, sodium acrylate heavy polymer can be used. Polymers, acrylic acid / acrylamide copolymers, polyethylene oxide-modified products, polyalkylene glycol copolymers, isobutylene / maleic anhydride copolymers, and the like can be used.

  Base fibers include natural fibers such as cotton and rayon and recycled fibers, polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polyester polymers such as biodegradable polyester; polyamide polymers such as nylon; polypropylene, low density Synthetic fibers such as polyolefin polymers such as polyethylene and high-density polyethylene can be used. Furthermore, a copolymer mainly composed of these or a mixture thereof can also be used.

As the fibrous water-absorbing resin and the base fiber, either short fibers or long fibers can be used. A web is made from a short fiber or a long fiber using a known method such as a direct spinning method such as a spun bond method or a melt blow method, a dry method such as carding or air lay, or a wet method such as a paper making method, and is made of a nonwoven fabric. A sheet part can be obtained.
As a method for obtaining a nonwoven fabric sheet portion by integrating a base fiber web and a fibrous water-absorbent resin, a thermal bonding method such as a calender method or a through air heating method, a chemical bonding method using an adhesive, and the like. In addition, a known method such as a mechanical bonding method such as a needle punch method, a hydroentanglement method, or a stitch bond method can be employed.

  The sheet portion may be a woven fabric. In this case, the fibrous water-absorbing resin can be woven into the woven fabric in which the base fiber is woven. Moreover, after attaching an uncrosslinked water-absorbing resin to the base fiber, a base yarn in which the base fiber and the water-absorbing resin are integrated is manufactured by a cross-linking reaction, and this is woven to obtain a sheet portion. Can do. In addition, after obtaining a woven fabric in which the base fiber is woven, an uncrosslinked water-absorbing resin is attached to the base fiber, and the base fiber and the water-absorbing resin are integrated by a cross-linking reaction. Can be obtained.

In particular, the sheet part is made of a base fiber web by a direct spinning method such as a spunbond method or a melt blow method, and a fibrous water-absorbing resin is applied to the machine by a needle punch method, a hydroentanglement method, a stitch bond method, or the like. What is made into a nonwoven fabric by the entanglement by the mechanical adhesion method is used suitably. This is because the fibrous water-absorbing resin and the base fiber do not fall off and are excellent in productivity.
As a structure of a sheet | seat part, a base fiber web and the water absorbent resin layer by fibrous water absorbent resin can be arbitrarily entangled, and it can be made to laminate | stack by arbitrary number of layers. In particular, the water-absorbent resin layer is preferably used in which both sides of the water-absorbent resin layer are sandwiched between base fiber webs and entangled. This is because the fibrous water-absorbing resin can be prevented from falling off, and even when the water-absorbing resin swells, the strength of the sheet portion can be prevented from being lowered.

  If the nonwoven fabric is entangled with the water absorbent resin and the base fiber, the volume of the water absorbent resin is suppressed by the base resin, and the sheet portion does not lose its shape even if the water absorbent resin swells. It can be used as a water-retaining material having regularity.

When voids are formed in the soil due to the difference in volume expansion of the water retention material, the evaporation of water in the soil is accelerated in summer, the temperature of the soil rises, and in winter the volume expands when the water accumulated in the voids freezes. However, problems such as cutting of roots of plants occur.
However, by adjusting the basis weight of the sheet part and the mixing ratio of the water-absorbing resin, an appropriate space is provided between the fibers of the sheet part at the time of drying, and further, the water-absorbing resin is surrounded by the base fiber, Even when the resin swells and the increased volume is absorbed in the space between the fibers and the water-absorbing resin swells, it is possible to prevent the entire sheet portion from expanding and the water retaining material from becoming indefinite. As a result, when buried in the soil, the volume of the water retention material does not change due to swelling or drying, so that the base is prevented from collapsing, and voids due to the volume expansion difference of the water retention material are formed in the soil. Can be prevented. Furthermore, since an air layer is formed, root rot can be prevented.

  The mixing ratio of the water-absorbent resin with respect to the total weight of the sheet portion is 5 to 70% by weight, preferably 15 to 30% by weight. As the water-absorbing resin is less than 15% by weight, the amount of water absorption decreases and the ability to supply water to the plant decreases, and the tendency to suppress the frost damage of the soil is seen, and as it exceeds 30% by weight, When the water-absorbent resin wets, the strength of the sheet portion decreases, and the sheet portion cannot absorb the swelling of the water-absorbent resin when wet, the water retaining material expands, the base collapses, and the plant roots break. There is a trend. In particular, when the amount is less than 5% by weight or more than 70% by weight, these tendencies become remarkable, so that neither is preferable.

The communication hole formed in the sheet portion includes a continuous gap and / or a through hole penetrating in the thickness direction of the sheet portion.
Here, the continuous space | gap is formed between the fibers which form a sheet | seat part, and it is obtained by adjusting a fabric weight and adjusting the density between fibers roughly. This continuous space is a space that can be penetrated by the growing roots, and varies greatly depending on the plant to be vegetated, but the vegetation effect is improved by forming the average space diameter of each space to about 5 μm to several mm. be able to. By forming such continuous voids, for example, a plant having a large number of capillary roots such as lawn has better rooting through the water retaining material and rooting in the soil than in the case where through holes are formed.

  The shape of the through hole is not particularly limited, and for example, a polygonal shape such as a circular shape, an elliptical shape, a triangular shape, a rectangular shape, a hexagonal shape, or a notch such as a linear shape, a curved shape, a slit shape, a cross shape, etc. It can be selected and used. There is no restriction | limiting in particular as a magnitude | size of a through-hole, For example, a major axis can be about 3-20 cm.

  The planar shape of the sheet part is not particularly limited, and for example, a sheet shape cut into a circular shape, an elliptical shape, a triangular shape, a rectangular shape, a hexagonal shape or the like, or a belt shape can be appropriately selected and used. .

Invention of Claim 2 of this invention is a water retention material of Claim 1, Comprising: It is provided with the holding part which supports the at least single side | surface of the said sheet | seat part, At least 1 which a plant root passes to the said holding part It has the structure provided with the communication part formed above.
With this configuration, in addition to the operation obtained in the first aspect, the following operation can be obtained.
(1) Since the holding part significantly improves the formability of the water-retaining material when absorbing water, it can be applied to slopes and wall surfaces such as slopes or wall surfaces in addition to horizontal use, and is excellent in versatility.
(2) Since the roots pass through the holding part through the communicating part, and the roots can be stretched directly and deeply into the soil, the root growth is not hindered, and thus the growth of the foliage on the ground is not hindered. Excellent effect.
(3) By forming the communicating part as a continuous gap, the roots can grow and grow in this gap, and the root can be deeply stretched directly into the soil through the holding part. Furthermore, an air layer is formed inside the holding part to prevent root decay. (4) Since the communicating part can be formed as a through hole penetrating in the thickness direction of the sheet, the root of the plant will eventually be held through the through hole. Since it can pass through the part and directly root in the soil, it has excellent vegetation effect.

By providing a holding portion on at least one surface of the seat portion to improve the formability, the water retaining material can be applied to sloped surfaces such as slopes or wall surfaces and vertical surfaces in addition to horizontal use.
As the holding portion, at least one surface of the sheet portion is heat-treated, and a substantially skin layer is formed so as to have a communicating portion through which plant roots can pass, thereby improving the formability. Furthermore, a base fabric can be joined as a holding part to at least one surface of the sheet part to improve the formability.

  A holding | maintenance part can be formed in a nonwoven fabric and a textile fabric by the above-mentioned method using the fiber similar to a base fiber. Further, the planar shape of the holding portion can be appropriately selected and used as the planar shape of the sheet portion. The communication holes, continuous gaps, and through holes are the same as those in the sheet portion, and thus description thereof is omitted.

  As a method of integrating the base fabric with the sheet portion, the sheet portion can be entangled together when the base fabric formed on the nonwoven fabric or the woven fabric is entangled with the base fiber and the water absorbent resin. And can be integrated.

When used on slopes such as slopes, it can be fixed to the ground with bamboo piles, wooden piles, or the like, or the water retention material can be suppressed to the ground with lath tension such as metal lath or wire lath. In addition to the lath, a conventionally known technique can be used, such as fixing to the ground with a net-like material such as a vegetation net made of a synthetic resin such as polyethylene, polyamide, or polyester or a biodegradable resin. .
In addition, it can be applied to an elevation by fixing a water retaining material to a frame such as a frame, or by holding it with a net-like material such as a lath or a vegetation net after being fixed to the frame.

Invention of Claim 3 of this invention is a water retention material of Claim 1 and 2, Comprising: The said through-hole has the structure formed by the notch | incision.
With this configuration, in addition to the effects obtained in claims 1 and 2, the following effects can be obtained.
(1) In the case of drilling a through hole having a circular shape, an elliptical shape, a triangle, a rectangular shape, etc., the perforated part is removed and the through hole is formed. The water-retaining material obtained in Items 1 and 2 can be used as it is, and since the through hole is formed by cutting, the sheet portion integrated with the water-absorbing resin can be used without waste, saving resources. Excellent in properties.
(2) By making the incision, the space of the incision part improves the adhesion between the water retaining material and the soil, and is familiar with the soil and helps prevent landslides.

  Here, as the cut, a linear shape, a curved shape, a slit shape, a cross shape, or the like is used. In particular, a plurality of cuts that are formed in a mesh shape or a cross shape with their positions shifted in a certain direction are preferably used. When storing or transporting, the incision is kept closed, and when embedding in the soil, both ends of the water retention material can be pulled in the direction orthogonal to the incision to open the notch and greatly extend the water retention material. Therefore, it is possible to reduce the size of the water retention material during storage and transportation, and it is possible to extend a small water retention material during construction and embed it in a wide cultivated land or desert. This is because the resulting space improves the adhesion with the soil and is well-familiar with the soil and helps prevent landslides.

Invention of Claim 4 of this invention is a water retention material of Claim 1 thru | or 3, Comprising: The said base fiber has the structure welded by the wall part thru | or peripheral part of the said through-hole. ing.
With this configuration, in addition to the actions obtained in claims 1 to 3, the following actions are obtained.
(1) When the base fiber is welded at the wall portion or the peripheral portion of the through hole, it is blocked by the weld portion of the base fiber and the water absorbent resin is difficult to unravel. Is prevented from falling off, ensuring the water absorption of the through hole, improving the strength of the wall portion or the peripheral portion of the through hole, and preventing a decrease in the strength of the sheet portion around the through hole when wet. it can.

  Here, in order to weld the base fiber, the base fiber is made of polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polyester polymer such as biodegradable polyester; polyamide polymer such as nylon; polypropylene, low density A thermoplastic resin such as a polyolefin polymer such as polyethylene or high density polyethylene is used.

A fifth aspect of the present invention is the water retention material according to any one of the first to fourth aspects, wherein the water-absorbing resin is welded at a wall portion or a peripheral portion of the through hole. It has a configuration.
With this configuration, in addition to the action obtained in any one of claims 1 to 4, the following action is obtained.
(1) When the water-absorbing resin is welded at the wall portion or the peripheral portion of the through-hole, the welded portion of the water-absorbing resin is entangled with the base fiber, and the fibrous water-absorbing resin drops from the through hole. It is possible to prevent this and to ensure the water absorption of the through hole.

  In claim 3 or 4, by heating the mold or blade for drilling the through-hole, or by drilling the through-hole using a laser, simultaneously forming the through-hole in the sheet portion, The water absorbent resin can be welded at the wall portion of the through hole. In addition, after drilling the through hole, by using a hot press machine or the like, the peripheral portion of the through hole is heat-bonded in the thickness direction of the sheet portion, so that the base fiber and the water-absorbent resin are removed at the peripheral portion of the through hole. Can be welded.

Invention of Claim 6 of this invention is a water retention material in any one of Claim 1 thru | or 5, Comprising: It has the structure provided with the ultraviolet-ray shielding layer formed in the surface of the said sheet | seat part. ing.
With this configuration, in addition to the action obtained in any one of claims 1 to 5, the following action is obtained.
(1) Since the ultraviolet ray shielding layer is formed on the surface of the sheet portion, the water absorbent resin is hardly affected by ultraviolet rays and sunlight after being embedded in the soil, and the water absorbency of the water absorbent resin is hardly lowered. Excellent long life.

Here, the ultraviolet shielding layer can be formed by applying or spraying a solution or dispersion of an ultraviolet shielding agent (ultraviolet absorber or ultraviolet reflector) onto the surface of the sheet portion. The UV shielding agent solution or dispersion is prepared by dissolving or dispersing the UV absorber or UV reflector in a solution in which a film-forming element such as phenol resin, alkyd resin, amino resin, acrylic resin emulsion, or polymer emulsion is diluted. Can be obtained.
In addition, inorganic particles having a solid UV shielding agent can also be used.
The ultraviolet shielding layer can be formed to a thickness of 1 to 100 μm, depending on the type of ultraviolet shielding agent. If the thickness of the ultraviolet shielding layer is less than 1 μm, it is difficult to obtain the ultraviolet shielding effect, and even if it is thicker than 100 μm, the ultraviolet shielding effect does not change, and the ultraviolet shielding layer easily falls off, which is not preferable.

Examples of the ultraviolet screening agent include salicylic acid derivatives such as methyl salicylate, pt-butylphenyl-salicylate, p-octylphenyl-salicylate; 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-n-octoxybenzophenone, Benzophenone compounds such as 4-dodecyloxy-2-hydroxybenzophenone; 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, 2- (2′-hydroxy-3′-t-butyl-5′-methyl) Benzotriazole compounds such as phenyl) benzotriazole and 2- (2′-hydroxy-3 ′, 5′-di-t-amylphenyl) benzotriazole; coumarin compounds, 2′-ethylhexyl-2-cyano-3, 3-diphenyl acrylate, etc. It can be used as a mixture of more than species or two or.
In addition, examples of the ultraviolet shielding agent include inorganic particles such as titanium oxide, zinc oxide, zirconium oxide, praseodymium oxide, cerium oxide, clay, crushed red clay, mineral powder such as activated carbon, shirasu, and diatomaceous earth, and abrasive powder. it can.

The invention according to claim 7 of the present invention is the water retention material according to claim 6, wherein the ultraviolet ray shielding layer has a configuration containing inorganic particles.
With this configuration, in addition to the operation obtained in the sixth aspect, the following operation can be obtained.
(1) The gap formed between the inorganic particles contained in the ultraviolet shielding layer functions as a filter for the pollutant contained in the polluted water, and prevents the pollutant from being absorbed into the space inside the sheet portion. . This prevents the swollen water-absorbing resin from protruding from the gap between the fibers of the sheet part, and prevents the water-absorbing resin from falling off by repeating shrinkage due to drying and swelling due to water absorption, and maintains water absorption for a long period of time. Can do. The space inside the seat part is provided to absorb the volume increased by swelling of the water absorbent resin, but when the contaminants are absorbed into the internal space and the contaminants are clogged in the space, Since the water-absorbing resin whose volume has been swollen and protrudes from the gap between the fibers of the sheet portion, the water-absorbing resin easily falls off by repeating shrinkage due to drying and swelling due to water absorption, and the water absorption decreases early. is there.

Here, the inorganic particles are dispersed on the surface of the sheet portion, and a web of natural fibers or synthetic fibers is disposed thereon, and the whole is entangled by a mechanical bonding method such as a needle punch, thereby An ultraviolet shielding layer can also be formed by immobilizing inorganic particles on the surface.
Inorganic particles include titanium oxide, zinc oxide, zirconium oxide, praseodymium oxide, cerium oxide, clay, reddish earth ground powder, activated carbon, shirasu, diatomaceous earth mineral powder, abrasive powder, etc. Can be used.
As the average particle size becomes larger than 50 μm, the gap formed between the inorganic particles tends to become larger and it becomes difficult to function as a filter for contaminants. As the average particle size becomes smaller than 1 μm, microbial colonies are more likely to occur. There is a tendency that the water is blocked and water is hardly absorbed.

The invention according to claim 8 of the present invention is the water retention material according to claim 7, wherein the inorganic particles are clay and / or abrasive powder.
With this configuration, in addition to the operation obtained in the seventh aspect, the following operation can be obtained.
(1) Since clay and abrasive powder have high cohesiveness, a strong ultraviolet shielding layer can be formed, the ultraviolet shielding effect is great, and the filtration performance of contaminants is high, preventing the entry of contaminants into the sheet portion. Is big.

Here, the clay is an aggregate of fine particles formed by decomposing and destroying minerals in rocks, and is mainly composed of fine particles of clay minerals.
Clay minerals include kaolinites such as kaolinite and decaitite, halloysites such as metahalloysite and halloysite, serpentine such as chrysotile and antigolite, hydromica such as sericite and sea chlorite, montmorillonite and beidellite. Montmorillonites such as chlorite, chlorite such as chlorite and magnesium chlorite, and aluminosilicate minerals such as pyrophyllite, talc and vermiculite are used. Moreover, as clay, plastic clays such as Kibushi clay and Sasame clay, kaolin, sericite, porcelain stone, wax stone clay, bentonite and the like can be used.

  As the abrasive powder, powder generated by weathering action of slate or shale, abrasive powder generated when cutting the abrasive stone, powder obtained by burning ocher powder, or the like can be used.

As described above, according to the water retention material of the present invention, the following advantageous effects can be obtained.
According to the invention of claim 1,
(1) The plant is replenished with moisture from the sheet part, and further, the roots can be stretched deeply and deeply through the through holes formed in the sheet part, so that the growth of the foliage on the ground is also prevented without hindering the root growth. A water retaining material excellent in vegetation effect can be provided without being hindered.
(2) Since the fibrous water-absorbing resin is integrated with the base fiber to form the sheet portion, the water-absorbing resin is difficult to drop off from the sheet portion, so that the shape of the sheet portion is maintained for a long period of time. Thus, it is possible to provide a water retention material excellent in durability that suppresses the expansion of the soil due to freezing and prevents the plant strain from being lifted and the roots being damaged or draining water.
(3) By adjusting the density between fibers, the communicating part can be formed into a continuous gap, and the roots of the plant extend through the continuous gap and eventually pass through the sheet part to directly root the soil into the soil. Can be stretched and has excellent vegetation effect. Moreover, since an air layer is formed, a water retention material having an excellent root rot prevention effect can be provided.
(4) Since the communicating part can be formed as a through-hole penetrating in the thickness direction of the sheet, the root of the plant passes through the through-hole and eventually passes through the sheet part, so that the root can be directly rooted in the soil. It is possible to provide a water retention material that is highly effective.
(5) The water-absorbing resin can surround the surroundings with the base fiber, and the water expansion of the water-absorbing resin at the time of water absorption is generated only in the space between the water-absorbing resin and the base fiber. The water expansion material which can suppress the volume expansion as a whole and is excellent in formability can be provided.

According to invention of Claim 2, in addition to the effect of Claim 1,
(1) Since the holding part remarkably improves the fixed formability of the water retaining material during water absorption, it can be applied to slopes and sloped surfaces such as slopes or wall surfaces in addition to horizontal use, and has excellent versatility. Can provide.
(2) Since the roots can pass through the holding part through the communicating part, and the roots can be spread directly and deeply into the soil, the root growth is not hindered, and the growth of the ground foliage is not hindered. A water retention material that can provide a good vegetation effect can be provided.
(3) By forming the communicating part as a continuous gap, the roots can grow and grow in this gap, and the root can be deeply stretched directly into the soil through the holding part. In addition, it is possible to provide a water retention material in which an air layer is formed inside the holding portion to prevent root rot.
(4) Since the communicating part can be formed as a through-hole penetrating in the thickness direction of the sheet, the root of the plant passes through the through-hole and eventually passes through the holding part, so that the root can be directly rooted in the soil. It is possible to provide a water retention material that is highly effective.

According to the invention described in claim 3, in addition to the effects of claims 1 and 2,
(1) The sheet portion integrated with the water-absorbing resin can be used without waste, and a water retention material excellent in resource saving can be provided.
(2) The space of the cut portion improves the adhesion between the water retention material and the soil, and can provide a water retention material having an effect of preventing landslides.

According to invention of Claim 4, in addition to the effect of Claims 1 to 3,
(1) The fibrous water-absorbing resin is prevented from falling off the through-hole, ensuring the water absorption of the through-hole and improving the strength of the wall and periphery of the through-hole, The water retention material which prevents the strength reduction of the sheet | seat part in can be provided.

According to invention of Claim 5, in addition to the effect of any one of Claims 1 to 4,
(1) It is possible to provide a water retention material that can prevent the fibrous water-absorbing resin from falling off the through-hole and ensure the water-absorbing property of the through-hole.

According to invention of Claim 6, in addition to the effect of any one of Claims 1 to 5,
(1) After being embedded in soil, the water-absorbing resin is not easily affected by ultraviolet rays or sunlight, and the water-absorbing resin is less likely to have a decrease in water absorption.

According to invention of Claim 7, in addition to the effect of Claim 6,
(1) The gap formed between the inorganic particles contained in the ultraviolet shielding layer functions as a filter for the pollutant contained in the polluted water, and prevents the pollutant from being absorbed into the space inside the sheet portion. Therefore, it is possible to prevent the water-absorbing resin from falling off, maintain the water-absorbing property for a long period of time, and provide a water retaining material having excellent long life.

According to the invention described in claim 8, in addition to the effect of claim 7,
(1) Since clay and abrasive powder have high cohesiveness, a strong ultraviolet shielding layer can be formed, the ultraviolet shielding effect is great, and the filtration performance of contaminants is high, preventing the entry of contaminants into the sheet portion. Therefore, it is possible to provide a water retention material that can maintain water absorption for a long period of time and has an excellent long life.

The perspective view of the water retention material in Embodiment 1 The principal part perspective view which shows the state which extended the water retention material in Embodiment 1. FIG. Main part sectional drawing of the sheet | seat part before the entanglement of the water retention material in Embodiment 1 Main part sectional drawing of the water retention material in Embodiment 1 Main part sectional drawing of the water retention material in Embodiment 2

Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings.
(Embodiment 1)
FIG. 1 is a perspective view of a water retention material in the first embodiment, FIG. 2 is a perspective view of a main part showing a state in which the water retention material in the first embodiment is extended, and FIG. 3 is a water retention material in the first embodiment. FIG. 4 is a cross-sectional view of a main part of the water retention material in the first embodiment.
In the figure, 1 is a water-retaining material in Embodiment 1 of the present invention, 2 is a fibrous water-absorbing resin 6 to be described later, and a base fiber web 5 on both sides thereof is a needle punch method, hydroentanglement method, stitch bond method A sheet portion made of a nonwoven fabric that is entangled and integrated into a rectangular shape by a mechanical bonding method such as a non-woven fabric having continuous voids therein, and is formed of fibers similar to the base fiber described later and continuous inside The holding part 4 which consists of the mesh ground which has a space | gap, a nonwoven fabric, and a textile fabric, 4 is a through-hole which consists of a linear notch which penetrated in the thickness direction of the sheet | seat part 2, and was formed in the water retention material 1, and consists of several notches The through-holes 4 are formed in a mesh shape in the sheet portion 2 and the base fabric 3 while being displaced in a certain direction. 5 is a base fiber web formed of base fibers made of thermoplastic resin such as polyethylene terephthalate by a spun bond method such as a spun bond method or a melt blow method, and 6 is a fibrous water absorption such as a sodium acrylate polymer. A water-absorbing resin layer 7a formed of resin and sandwiched between the base fiber webs 5 from both sides and integrated with the base fiber web 5, 7a is a sheet side wall portion of the through hole 4 formed in the water retaining material 1, and 7b Is the holding part side wall part of the through-hole 4 formed in the water retention material 1, and base fiber is welded by the sheet | seat part side wall part 7a and the holding part side wall part 7b.

An example of a manufacturing method for the water retention material according to Embodiment 1 of the present invention configured as described above will be described below.
The base fiber web 5 is formed by a direct spinning method such as a spun bond method or a melt blow method, and the water absorbent resin layer 6 is formed of the base fiber web 5 so that the fibrous water absorbent resin becomes an intermediate layer. The sheet portion 2 is obtained by interlacing the base fiber and the fibrous water-absorbing resin by interlacing them by a mechanical bonding method such as a needle punch method, a hydroentanglement method, or a stitch bond method. Here, the holding part 3 formed in the nonwoven fabric or the woven fabric with the base fiber is arranged on the base fiber web 5 so as to be entangled together with the sheet part 2 and bonded or formed after the sheet part 2 is formed. Join by welding or the like. Thereafter, the through hole 4 is formed using a mold, blade, laser, or the like heated to a temperature higher than the melting point of the base fiber, and at the same time, the sheet side wall portion 7a and the holding portion side wall portion 7b of the through hole 4 Weld the material fibers.
At this time, continuous voids are formed by adjusting the basis weight of the sheet part 2 and the holding part 3 and the mixing ratio of the water absorbent resin.

As mentioned above, since the water retention material in Embodiment 1 of this invention is comprised, the following effects are acquired.
(1) Since the sheet | seat part 2 is equipped with the space | interval which continued with the several through-hole 4 which penetrated in the thickness direction, the plant seed | inoculated on the water-retaining material 1 makes a root from the through-hole 4 and the continuous space | gap. It can be expanded to the deep part of the soil, and the vegetation effect can be enhanced without hindering the growth of the roots and thus without hindering the growth of the foliage on the ground. Moreover, when the through-hole 4 is formed, the familiarity with the soil is good and the slippage between the layers can be prevented, so that the sediment can be prevented from flowing out. And the continuous space | gap improves the rooting of the plant which has many capillaries.
(2) Since the fibrous water-absorbing resin is integrated with the base fiber to form the sheet portion 2, the water-absorbing resin is unlikely to fall off from the sheet portion 2, so that the shape of the sheet portion 2 is long-term. The water absorption is maintained. In addition, the water-absorbing resin is surrounded by the base fiber even if it absorbs water, and the volume expansion and displacement of the position are suppressed, and it can prevent freezing to about -20 degrees. Since the cushioning property is maintained, the expansion of the soil due to freezing is suppressed, and the plant strain is prevented from being lifted and the roots being damaged or draining.
(3) Since both sides of the fibrous water absorbent resin layer 6 are sandwiched between the base fiber webs 5 and entangled to form the sheet portion 2, the fibrous water absorbent resin is prevented from falling off and the water absorbent Even when the functional resin swells, the strength of the sheet portion 2 can be prevented from decreasing.
(4) Since the through-holes 4 made of a plurality of cuts are formed in a mesh shape with their positions shifted in a certain direction, the cuts are closed during storage or transportation, and are embedded in the soil. In addition, as shown in FIG. 2, since both ends of the water retaining material 1 can be pulled in the direction orthogonal to the notch and the notch can be opened to greatly extend the water retaining material 1, the water retaining material 1 during storage or transportation can be Miniaturization can be achieved. Moreover, at the time of construction, the small water-retaining material 1 can be extended and embedded in a wide cultivated land, desert, or the like, which is excellent in workability and resource saving.
(5) Since the base fiber of the sheet side wall portion 7a of the through hole 4 is welded, it is blocked by the welded portion of the base fiber so that the water absorbent resin is difficult to be released, so that the fibrous water absorbent resin penetrates. The hole 4 is prevented from falling off the sheet side wall part 7a and ensures water absorption in the through hole 4, and the strength of the sheet side wall part 7a and the holding part side wall part 7b of the through hole 4 is improved. The strength reduction of the water retaining material 1 around the through hole 4 can be prevented.
(6) Since the sheet part 2 is supported by the holding part 3, the water retaining material 1 has excellent formability and is used not only for horizontal surfaces but also for vertical surfaces, slopes, slopes, etc. The shape of the water retaining material 1 is remarkably stable without being indefinite during use.
(7) Since the through-hole 4 is formed, the space obtained by the through-hole 4 enhances the adhesion between the water retention agent 1 and the soil, and thus has an effect of preventing landslide.

Here, in the first embodiment, the case where the through hole 4 is formed by a linear cut has been described, but the cut may be a curved shape or a slit shape. Moreover, although the case where the cut was formed in a mesh shape has been described, it may be provided in a cross shape. In these cases, the same effect can be obtained. In some cases, through-holes such as a circular shape, an elliptical shape, a triangular shape, a rectangular shape, and a hexagonal shape are formed by punching or punching instead of cutting.
Further, the through hole 4 is formed using a mold, blade, laser, or the like heated to a temperature equal to or higher than the melting point of the base fiber, and at the same time, the base material is formed by the sheet side wall 7a and the holding side wall 7b. Although the case where fibers are welded has been described, after forming the through-hole 4 using a normal temperature mold or blade, the peripheral portion of the through-hole 4 is formed in the thickness direction of the sheet portion 2 using a hot press machine or the like. In some cases, the base fiber is welded at the peripheral portion of the through hole 4 by thermocompression. In this case, the same effect can be obtained. A similar effect can be obtained by welding the water-absorbing resin on the sheet side wall 7a and the holding side wall 7b or the peripheral part of the through hole 4.
Moreover, although the case where the sheet | seat part 2 was formed in the rectangular shape was demonstrated, it may be set as a elongate strip | belt shape, without dividing | segmenting into a rectangular shape. Thereby, it is excellent in workability in the case of embedding in a wide cultivated land or desert.

(Embodiment 2)
FIG. 5 is a cross-sectional view of a main part of the water retention material in the second embodiment. In addition, the same thing as Embodiment 1 attaches | subjects the same code | symbol, and abbreviate | omits description.
In the figure, 1a is a water retentive material in Embodiment 2, and 8 is an ultraviolet light shielding layer formed on the surface of the water retentive material 1 and containing an ultraviolet light shielding agent such as inorganic particles such as clay and abrasive powder, and a salicylic acid derivative.
In the water retaining material 1a, the base fiber web 5 is formed of natural fibers such as cotton and rayon, regenerated fibers, and synthetic fibers made of thermoplastic resin such as polyethylene terephthalate by a direct spinning method such as a spun bond method or a melt blow method. Yes.

An example of the manufacturing method of the water retention material according to the second embodiment of the present invention configured as described above will be described below.
A base fiber web 5 is formed by a spun bond method such as a spun bond method or a melt blow method, and a water absorbent resin layer 6 of a fibrous water absorbent resin is used as an intermediate layer. The sheet part 2 is sandwiched and entangled by a mechanical bonding method such as a needle punch method, a hydroentanglement method, or a stitch bond method, and the base fiber and the fibrous water-absorbing resin are integrated to obtain the sheet portion 2. Here, the holding part 3 formed in the nonwoven fabric or the woven fabric with the base fiber is arranged on the base fiber web 5 so as to be entangled together with the sheet part 2 and bonded or formed after the sheet part 2 is formed. Join by welding or the like. After the through-hole 4 is formed in the sheet part 2, the surface of the sheet part 2 is applied by spraying, etc., a solution or dispersion of an ultraviolet shielding agent (ultraviolet absorber or ultraviolet reflective agent) on the surface of the sheet part 2. Then, an ultraviolet shielding layer 8 is formed. In this way, the water retention material 1a in Embodiment 2 is obtained.

As described above, since the water retention material according to the second embodiment of the present invention is configured, the following action is obtained in addition to the action described in the first embodiment.
(1) Since the ultraviolet shielding layer 8 is formed on the surface of the sheet portion 2, after being embedded in the soil, the water absorbent resin is not easily affected by ultraviolet rays or sunlight, and the water absorbent resin is reduced in water absorption. Because it is difficult, it has excellent long life.
(2) In the case where the ultraviolet shielding layer 8 contains inorganic particles, the gap formed between the inorganic particles functions as a filter for contaminants contained in the contaminated water, and the space inside the sheet portion 2 Prevents contaminants from being absorbed. As a result, the swollen water-absorbing resin protrudes to the outside from the gap between the fibers of the sheet portion 2, and prevents the water-absorbing resin from falling off by repeating shrinkage due to drying and swelling due to water absorption, and maintains water absorption for a long period of time. be able to.

Hereinafter, the present invention will be specifically described by way of examples. The present invention is not limited to these examples.
(Manufacture of water retaining materials)
20 samples of water retention materials were produced by the production method shown below.
First, a polyethylene terephthalate resin was supplied to a conventional spunbond melt spinning apparatus, and was uniformly melt-mixed and taken up to obtain polyethylene terephthalate fibers. The obtained polyethylene terephthalate fiber was spread and dispersed to form a base fiber web.
Next, a non-woven fabric having a basis weight of 68 to 69.5 g / m ² was formed of the above-described polyethylene terephthalate fiber as a holding portion.
Next, a fibrous sodium acrylate polymer (water-absorbing resin) is sandwiched between base fiber webs, and a holding portion is disposed on one base fiber web, and needle punching is performed to perform the water-absorbing resin and polyethylene. The holding portion was joined while entangled terephthalate fibers to form a sheet portion, and a water retention material having a thickness of 5 mm made of a nonwoven fabric having a basis weight of 970 to 980 g / m ² was obtained. The mixing ratio of the water absorbent resin relative to the total weight of the sheet portion was 30 to 31% by weight. The water retaining material was cut into a rectangular shape having a width of 250 mm and a length of 600 mm.

Example 1
6 parts by weight of abrasive powder (ultraviolet shielding agent) having an average particle size of 3 μm was dispersed in an acrylic resin emulsion to obtain a dispersion of ultraviolet shielding agent. This was applied to the surface of the water retention material and dried to obtain the water retention material of Example 1 in which an ultraviolet shielding layer having a thickness of about several μm was formed.
(Example 2)
After adding 100 parts by weight of 2- (2′-hydroxy-3 ′, 5′-di-t-amylphenyl) benzotriazole (ultraviolet screening agent) to 100 parts by weight of a mixed solvent of xylene and methyl isobutyl ketone, the mixture is stirred. Polymethylmethacrylate (coating film forming element) was mixed to obtain a UV shielding agent solution. This was applied to the surface of the water retention material and dried to obtain a water retention material of Example 2 in which an ultraviolet shielding layer was formed.
(Comparative Example 1)
The above water retaining material in which the ultraviolet shielding layer was not formed was used as the water retaining material of Comparative Example 1.

(Evaluation of water absorption performance of water retaining material embedded in soil)
The water-retaining materials of Examples 1 and 2 and Comparative Example 1 were embedded almost horizontally at a distance of 30 cm from the surface of the field into soil having a depth of 5 cm. In addition, the field where the water retaining material is buried is provided outdoors where the sun shines when it is fine and rains when it rains.
After embedding the water-retaining material, water was gently irrigated from the surface until the soil surface where the water-retaining material was embedded was completely wetted.
In this state, it was left for 8 months from January to August. Irrigation was performed once a week regardless of the weather. The water absorption performance of the water retaining material embedded in the soil was evaluated by measuring the wet and dry conditions in the soil.
The wet and dry condition in the soil was measured using a soil acid hygrometer (manufactured by Takemura Electric Co., Ltd., Model DM-15) at a frequency of about once every two weeks when it was visually recognized that the ground surface was dry. . Insert the electrode of the soil acid hygrometer (DM-15 type) to the top surface of the water retention material in the soil, read the numerical value indicating the dryness and wetness in the soil (show the numerical value of 1 to 8 according to the dryness and wetness), and compare this value Thus, the water absorption performance of the water retaining material was evaluated.
As a result, the soil in which the water retention material of Comparative Example 1 was embedded was not affected by the upper surface of the water retention material even when it was visually recognized that the ground surface was dry until about 3 months (until March to April) after the water retention material was embedded. The soil humidity was a humidity suitable for the growth of plants (for example, cucumbers, watermelons, strawberries, etc.) (soil acid hygrometer values were 4-6). However, after that, the numerical value gradually decreased, and in July to August, the numerical value was 1 to 2 except immediately after irrigation or rainfall.
On the other hand, the soil humidity of the soil in which the water retention material of Example 1 was embedded (the soil on the upper surface of the water retention material) was 4 to 6 even in July to August. Moreover, although the soil humidity of the soil (the soil on the upper surface of the water retaining material) in which the water retaining material of Example 2 was embedded decreased from 3 to 4 in July to August, the soil humidity was 4 to 6 in January to June. Numbers were shown.

According to the above example, since the water retention material of Example 1 has a strong ultraviolet shielding layer made of abrasive powder, the ultraviolet shielding effect is large, and the filtration performance of the contaminants is high, so that the contaminants are in the sheet portion. It is presumed that the water absorption is maintained for a long time because the effect of preventing the intrusion is great.
In addition, since the water-retaining material of Example 2 is formed with an ultraviolet shielding layer, the water-absorbing resin is not easily affected by ultraviolet rays or sunlight, and the water-absorbing resin is less likely to have a reduced water absorption. It is presumed to be excellent.
On the other hand, since the water retention material of Comparative Example 1 does not have an ultraviolet shielding layer, it is presumed that the water absorption of the water absorbent resin is lowered early due to the influence of ultraviolet rays and sunlight, and the long-life property is lacking. The

  The present invention relates to a water retaining material embedded in the soil, can stretch the roots deeply and broadly without hindering the growth of the roots of the plant, excellent vegetation effect, moreover, the water-absorbent resin is difficult to fall off the sheet portion, for a long period of time, The shape of the seat is maintained, water absorption is maintained, soil expansion due to freezing is suppressed, and because it has excellent formability, it can be used on vertical surfaces, slopes, and slopes in addition to use on horizontal surfaces, and is durable And can provide a water retaining material with excellent versatility.

DESCRIPTION OF SYMBOLS 1,1a Water retention material 2 Sheet | seat part 3 Holding | maintenance part 4 Through-hole 5 Base fiber web 6 Water absorbent resin layer 7a Sheet | seat part side wall part 7b Holding | maintenance part side wall part 8 Ultraviolet ray shielding layer

Claims (8)

(A) a sheet portion in which a fibrous water-absorbent resin and a base fiber are integrated;
(B) comprising at least one communicating portion through which plant roots pass through the sheet portion,
The water retention material, wherein the communication part is a continuous gap and / or a through hole penetrating in a thickness direction of the sheet part.   The water retention material according to claim 1, further comprising a holding portion that supports at least one side of the sheet portion, and the holding portion includes at least one communicating portion through which plant roots pass.   The water retaining material according to claim 1 or 2, wherein the through hole is formed by cutting.   The water retention material according to claim 1, wherein the base fiber is welded at a wall portion or a peripheral portion of the through hole.   The water retention material according to any one of claims 1 to 5, wherein the water-absorbing resin is welded at a wall portion or a peripheral portion of the through hole.   The water retention material according to any one of claims 1 to 5, further comprising an ultraviolet shielding layer formed on a surface of the sheet portion.   The water retention material according to claim 6, wherein the ultraviolet shielding layer contains inorganic particles. The water retention material according to claim 7, wherein the inorganic particles are clay and / or abrasive powder.

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