JP2009078477A - Laminate sheet and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laminate sheet suitable as a water-permeable weed proof sheet along the rugged shape of the soil, and its manufacturing method. <P>SOLUTION: A light-blocking laminate sheet is formed by stacking hydrophilic unwoven cloth obtained from a semirandom web or a parallel web and a porous film and provided with air permeability of 10 to 500 cc/cm<SP>2</SP>×sec. The manufacturing method of the laminate sheet comprising bonding melt-blow unwoven cloth and the hydrophilic unwoven cloth obtained from the semirandom web or the parallel web by heat, is provided. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to a sheet used in the field of agriculture, and provides moisture to the soil by allowing water given by rain or irrigation from the sheet to be provided to the soil while suppressing moisture transpiration of the soil, and Further, the present invention relates to a sheet that can suppress the propagation of weeds and the like.

  Agricultural sheets are used by laying directly on the cultivation ground for fruit trees, vegetables, etc., and transpiration of moisture required by plants by suppressing the growth of weeds by covering the soil and covering the soil. It has been proposed that the water content can be compensated by suppressing rainwater or penetrating rainwater from the sheet. For these agricultural sheets, sheets having a herbicidal and water-permeable function are required, and various proposals have been made (see Patent Documents 1 and 2). However, there are many uneven parts in the soil where fruits and vegetables are grown, and it is pointed out that the problem is that the soil along the soil is difficult. If the soil is poor, the foot may be caught when walking on the agricultural sheet, or the sheet may be peeled off by the wind. Therefore, there is a strong demand for improvement of these problems.

Japanese Patent Laid-Open No. 10-262472 Japanese Patent Laid-Open No. 9-248070

  In view of the above-described background, an object of the present invention is to provide a laminated sheet suitable as a water-permeable weed-proof sheet that easily conforms to the uneven shape of soil and a method for producing the same.

The present invention solves the above-described problems, and is a laminated sheet obtained by laminating a hydrophilic nonwoven fabric and a porous film, and is provided in at least one of the hydrophilic nonwoven fabric and / or the porous film. A laminated sheet comprising a light-shielding pigment, wherein the hydrophilic nonwoven fabric is a nonwoven fabric obtained from a semi-random web or a parallel web, and the air permeability of the laminated sheet is 10 to 500 cc / cm ² · sec. And a manufacturing method thereof.

  According to the present invention, it is possible to obtain a sheet that has excellent water permeability and moderate soil moisture retention and is easy to follow along the unevenness of the soil. Specifically, the hydrophilic nonwoven fabric functions to efficiently infiltrate water into the back surface and suppress the transpiration of water once infiltrated into the soil by the porous film. Suppressing the transmission of sunlight necessary for weed growth with a light-shielding pigment, and using a semi-random web or a parallel web for the web constituting the nonwoven fabric, it is possible to obtain good softness and elongation easily along the uneven shape of the soil Can do.

The hydrophilic non-woven fabric constituting the laminated sheet of the present invention is not particularly limited, but synthetic fibers, natural fibers, natural plant fibers, animal proteins and the like are dissolved once and then chemically processed to form fibers. It can be obtained from recycled fibers, etc. having hydrophilicity, hydrophilic fibers made by imparting hydrophilicity to the surface of the fibers, or those obtained by blending the hydrophilic fibers with other fibers.
Examples of hydrophilic synthetic fibers include polyvinyl alcohol resins and polyamide resins, those having hydroxyl groups in the molecule, particularly those having monomer units, and more preferably having hydroxyl groups uniformly in the molecule. From such a viewpoint, polyvinyl alcohol (hereinafter sometimes abbreviated as PVA) fiber is preferable.
Examples of hydrophilic natural fibers include cotton, silk, and hemp.
Examples of hydrophilic regenerated fibers include cellulosic fibers such as rayon, lyocell, cupra, and polynosic.
As a method for imparting hydrophilicity to the surface of the fiber, a method of imparting a hydrophilic oil agent or resin to the surface of the fiber, a hydrophilic resin is made into a fiber together with the fiber-forming resin, and at least a part of the fiber surface is hydrophilic resin. There is a way to cover with. The method of covering the surface of the fiber with a hydrophilic resin is preferable because the deterioration of the hydrophilic performance over time is small. A method of fiberizing a hydrophilic resin together with a fiber-forming resin is preferable because the manufacturing process is shortened and uniform hydrophilicity can be imparted. In particular, it is preferable from the height of hydrophilicity to cover the entire surface of the fiber in a sheath shape with a hydrophilic resin.
The oil agent used for imparting hydrophilicity is not particularly limited, and examples thereof include phosphate ester alkali metal salts, propylene glycol, ethylene glycol butyl ether, stearic acid diethanolamide, polyoxyethylene behenic acid amide, and the like.
The hydrophilic resin used for imparting hydrophilicity is not particularly limited, and examples thereof include polyvinyl alcohol resins. Among these, an ethylene-vinyl alcohol copolymer is particularly preferable because a random copolymer can be easily obtained and a copolymerization ratio can be easily selected, so that necessary hydrophilicity can be uniformly introduced.
There are no particular restrictions on the fiber-forming resin used as the raw material for the fiber that imparts hydrophilicity, but the surface of the fiber made of fiber-forming resin that is not highly hydrophilic may be hydrophilized with a more hydrophilic oil or resin. Therefore, polyolefin resins such as polyethylene and polypropylene, polyester resins such as polyethylene terephthalate, polyamide resins such as nylon 6, nylon 6,6, and nylon 4,6, polyacrylonitrile resins, and the like can be given. .
The fiber length of the hydrophilic fiber is not particularly limited, but is preferably 20 to 70 mm, and particularly preferably 25 to 60 mm, from the viewpoint of card passing property, from the viewpoint that a uniform texture web is easily obtained. Adjust. The fineness of the hydrophilic fiber is preferably 0.5 to 7.0 dtex. In particular, when the fiber density of the hydrophilic nonwoven fabric is a laminated sheet when the fiber density is 1.0 to 5.0 dtex, water permeability and soil moisture retention are achieved. It is preferable in that a balance of properties can be easily obtained.
It is preferable to blend the hydrophilic non-woven fabric with another fiber to obtain a hydrophilic non-woven fabric, since the hydrophilicity, the bulk of the non-woven fabric, the strength of the non-woven fabric, and the like can be adjusted. There are no particular restrictions on the other fibers other than those that are usually easy to mix with hydrophilic fibers, but polyolefin fibers made of polyethylene, polypropylene, etc., polyester fibers made of polyethylene terephthalate, nylon 6, nylon 6, 6, polyamide fibers made of nylon 4, 6, etc., polyacrylonitrile fibers, polyurethane fibers and the like. The use of hydrophobic fibers such as polyester fibers is preferable in that it is easy to obtain a bulky hydrophilic nonwoven fabric, and it is easy to obtain a balance of water permeability when used as a laminated sheet and soil moisture retention.

The fiber length of these other fibers is not particularly limited, but is preferably 20 to 70 mm, particularly 25 to 60 mm, because the card has good passability and is easy to mix, and is adjusted as required. Further, if the fineness of these other fibers is 0.5 to 7.0 dtex, particularly 1.0 to 5.0 dtex, it is easy to obtain a balance of water permeability and soil moisture retention when used as a laminated sheet. Is preferable.
The hydrophilic nonwoven fabric preferably has a basis weight of 15 to 100 g / m ^{2 and} preferably has a thickness of 0.15 to 2.00 mm. By controlling the basis weight and thickness of the hydrophilic nonwoven fabric, the volume of the internal voids can be adjusted. Thickness and porosity affect water permeability and soil moisture retention. By controlling these, the water flow rate can be adjusted.

Among the above hydrophilic fibers, it is preferable to use polyvinyl alcohol (hereinafter sometimes abbreviated as PVA) fiber from the viewpoint of strength, durability, and ease of production.

  As content of PVA fiber, it is preferable to contain 6-100 mass% with respect to the whole hydrophilic fiber, and when mixing cotton, the above-mentioned other fiber is used.

  The PVA fiber used in the present invention is produced by solution spinning a spinning solution containing a PVA resin, specifically, wet spinning, dry wet spinning, or dry spinning. Solvents used in the spinning dope include solvents conventionally used in the production of PVA fibers, such as dimethyl sulfoxide (DMSO), dimethylformamide, dimethylacetamide, water, or polyvalent such as glycerin, ethylene glycol, triethylene glycol, etc. One kind or a combination of two or more kinds of alcohols, diethylenetriamine, rhodan salts and the like can be used. Among these, DMSO and water are particularly preferable from the viewpoints of availability and influence on environmental load. The resin concentration in the spinning dope varies depending on the composition of PVA resin, the degree of polymerization, and the solvent, but is generally in the range of 6 to 60% by mass. As long as the effects of the present invention are not impaired, additives such as antioxidants, antifreezing agents, pH adjusting agents, concealing agents, coloring agents, and oils are added to the spinning dope according to the purpose in addition to the PVA resin. Etc. may be included.

  The PVA fiber obtained by the solution spinning described above may be subjected to a stretching heat treatment in order to improve the crystallinity and orientation. The stretching heat treatment conditions are generally 210 ° C. or higher, preferably 220 to 260 ° C., and when stretched at a total stretching ratio of 8 times or more, preferably 10 to 25 times. The crystallinity and orientation of the fiber are increased, and the mechanical properties of the fiber are remarkably improved. In addition, the PVA fiber may be subjected to an acetalization treatment or other cross-linking treatment that is generally performed for PVA fibers for the purpose of improving hot water resistance, if necessary.

  The cross-sectional shape of the PVA fiber is not particularly limited, and may be, for example, a round cross section, a modified cross section, a polygonal cross section, or the like. Further, the single fiber fineness of the PVA fiber is not particularly limited, but is preferably 0.5 to 7.0 dtex, more preferably 1.0 to 5.0 dtex, from the viewpoint of mechanical properties, water absorption, water retention and the like of the nonwoven fabric. It is. On the other hand, the average fiber length of the PVA fibers is preferably 20 to 70 mm, more preferably 25 to 60 mm.

  The hydrophobic fiber to be blended with the hydrophilic nonwoven fabric used in the present invention is a fiber having an official moisture content of less than 5% in a standard state (20 ° C., 65% RH) and a melting point of 160 ° C. or more. Polyester fibers, polyolefin fibers, polyacrylonitrile fibers, etc., among which polyester fibers, particularly polyethylene terephthalate fibers are preferred.

The cross-sectional shape of the hydrophobic fiber is not particularly limited. For example, various cross-sections such as a round cross section, an irregular cross section, a polygon cross section, a multilobal cross section, a hollow cross section, a V shape, a T shape, an H shape, and an array shape. Etc.
In addition, the single fiber fineness of the hydrophobic fiber is preferably 0.5 to 7.0 dtex, more preferably 1.0 to 5.0 dtex, from the viewpoint of ensuring card passage and an appropriate non-woven fabric density. On the other hand, the average fiber length of the hydrophobic fiber is preferably 20 to 70 mm, more preferably 25 to 60 mm.

  In the case of imparting hydrophilicity to a fiber made of a hydrophobic resin, it is preferable to use a hydrophilic fiber oil because a hydrophilic fiber can be obtained at a low cost. The hydrophilic fiber oil used for the hydrophobic fiber is not particularly limited, and examples thereof include phosphate ester alkali metal salts, propylene glycol, ethylene glycol butyl ether, stearic acid diethanolamide, polyoxyethylene behenic acid amide, and the like. Among them, a combination with an alkali metal phosphate ester is preferable, and specifically, mono-, di- and triester alkali metal salts of phosphoric acid having an alkyl group or an aliphatic ether group, for example, C8-C18 alkyl phosphate esters. Examples include alkali metal salts and diethyl ether phosphate alkali metal salts. Examples of the alkali metal salts include sodium salts and potassium salts. In particular, C10-C13 alkyl phosphate potassium salts are preferably used in that high durability can be obtained.

On the other hand, in order to laminate the hydrophilic nonwoven fabric used for this invention with a porous film, an adhesive fiber can be used for a hydrophilic nonwoven fabric. Here, the adhesive fiber may be any fiber that promotes adhesion with the porous film at the time of lamination, but is preferably one whose adhesion is lowered after lamination, for example, at the time of use. Examples of such adhesive fibers include heat-fusible fibers. The kind of the heat-fusible fiber constituting the hydrophilic nonwoven fabric used in the present invention is not particularly limited, but it is desirable to use a fiber having a low melting point resin having a melting point of 150 ° C. or lower as one component, for example, a low melting point resin. A single fiber (for example, polyethylene fiber) or a core having a high melting point resin (such as a polyester resin or a polyamide resin) as a core component and a low melting point resin (for example, a polyethylene resin or a modified polyester resin) as a sheath component. A sheath type composite fiber or the like can be used.
Among these, from the viewpoint of excellent weather resistance, a heat-fusible fiber made of a polyester resin is preferable, and it is particularly preferable to use a core-sheath type composite fiber in which the core component is polyethylene terephthalate and the sheath component is a modified polyester.
Further, the single fiber fineness of the heat-fusible fiber is preferably from 0.5 to 7.0 dtex, more preferably from 1.0 to 5.0 dtex, from the viewpoint of card passability. On the other hand, the average fiber length is preferably 20 to 70 mm, more preferably 25 to 65 mm.

The hydrophilic nonwoven fabric used in the present invention preferably uses 6 to 100% by mass of the above-described hydrophilic fiber, more preferably 20 to 81% by mass, and still more preferably 30 to 55% by mass. In addition, it is preferable to use 30 to 70% by mass of the hydrophobic fiber because water permeability is increased while maintaining hydrophilicity. The ratio of the hydrophobic fiber takes into account the mass of the hydrophobic fiber even in the case of a hydrophilic fiber obtained by hydrophilic treatment of the surface of the hydrophobic fiber with a resin or an oil material. That is, the mass ratio of the hydrophobic resin constituting the hydrophilic nonwoven fabric is considered. When hydrophilized using an oil agent, it is understood that the weight of the hydrophilized fiber is almost the same as that of the original hydrophobic fiber, and therefore it can be approximated using the weight of the fiber after the hydrophilization treatment. In the case of a composite fiber whose surface is coated with a hydrophilic resin in a core-sheath shape, it can be inferred from observation of the cross-sectional structure and specific gravity. Moreover, it is preferable to use 15 to 25% by mass of the adhesive fiber because not only the mechanical strength of the hydrophilic nonwoven fabric is improved but also the integration with the porous film is facilitated. The adhesive fiber can function as a part of the hydrophilic fiber and / or the hydrophobic fiber. The adhesive fiber is preferably a hydrophobic fiber because the water resistance of the nonwoven fabric is increased. It is most desirable to use non-adhesive hydrophilic fiber / non-adhesive hydrophobic fiber / adhesive hydrophobic fiber in a ratio of 55:30:15 to 30:45:25 as the hydrophilic non-woven fabric. It becomes possible to ensure the outstanding water permeability by making each into the above-mentioned ratio. In particular, when used for grass protection sheets, etc., if the water permeability is low, even if the water is sprayed, it will flow from the surface of the sheet. There is a risk that vegetables will die. That is, it needs to be quickly absorbed into the sprayed area.
Moreover, the water | moisture content absorbed by the ground needs to be water | moisture content moderately in soil, and needs to be gradually dehumidified. Sheets that are unlikely to release moisture may have excessive moisture and cause roots such as vegetables to rot.
In this invention, the said subject can be solved by using the nonwoven fabric of the said structure as a hydrophilic nonwoven fabric.

The porous film constituting the sheet of the present invention is a part for controlling the air permeability of the laminate in order to control the transpiration by allowing the water provided by rain or irrigation to permeate through the sheet.
Although the raw material of a porous film is not specifically limited, It manufactures from polyolefin, such as polyethylene and a polypropylene, polystyrene, polyester, polyamide, an ethylene-vinyl alcohol copolymer, a polyvinyl chloride, a polyvinylidene chloride, a polycarbonate, etc.
It is highly desirable that the porous film of the laminated sheet of the present invention communicates with the front surface and the back surface in order to control the transpiration of moisture.
The porous film of the present invention is desirably obtained from the following porous film.
It is preferred that the observed 100～760,000 pieces / cm ² of holes in the surface, more preferably to be able to observe 600～380,000 pieces / cm ² of holes, to be able to observe 3,000 to 30,000 pieces / cm ² of holes Further preferred. It is also preferable ^{to 5mm 2 / cm 2 ~60mm 2 /} cm 2 of holes can be observed on the surface.
Further preferably holes observed on the surface is 80~50,000μm ^2, further preferably 300~20,000μm ^2, and particularly preferably 1,000~5,000μm ^2.
The thickness of the porous film is preferably in the range of 0.01 to 1.0 mm (the actual product is 0.3 mm).
The method for producing the porous film is not particularly limited, however, it is possible to remove one of the films made of a plurality of resins by a method such as dissolution, a method for forming a porous pattern by a method such as printing, and a porous material such as a foaming agent. The method of forming quality, the method of obtaining the film of a woven fabric or a nonwoven fabric from a fiber, the method of laminating | stacking countless resin melt | dissolved in fiber form (melt blow method), etc. are mentioned.
Moreover, in order to laminate | stack with a hydrophilic nonwoven fabric, it can have adhesiveness. Here, the adhesive property is not limited as long as it promotes adhesion with the hydrophilic non-woven fabric at the time of lamination. For example, various binders, heat-sealable resins, and the like can be used, and it is preferable that the porous film itself is a heat-sealable resin because the pores are not blocked by the binder and the performance is not deteriorated.
In addition, when the porous film thus obtained is laminated, the original structure may be deformed, but the laminated sheet can obtain a desired effect depending on the properties of the original film.
For the porous film, it is preferable to use a melt-blown nonwoven fabric obtained by a melt-blowing method as a film by heat melting treatment for controlling the air permeability of the laminate or for a composite treatment with a hydrophilic nonwoven fabric. Preferably, it is a melt blown nonwoven fabric made of ultrafine fibers having an average fiber diameter of 15 μm or less and having a basis weight of 15 to 100 g / m ² . If the average fiber diameter of the fibers constituting the melt blown nonwoven fabric exceeds 15 μm, the air permeability may be increased, and the performance of keeping soil moisture from being suppressed may deteriorate.
From the viewpoint of water permeability and suppression of transpiration from the ground, the average fiber diameter of the fibers constituting the melt blown nonwoven fabric is preferably 15 μm or less, and more preferably 2 to 15 μm. Further, from the viewpoint of uniform permeability by appropriately diffused water that has imbued than the hydrophilic nonwoven fabric side to the ground, a basis weight of the meltblown nonwoven fabric is preferably ^{5~50g / m 2, 10~30g / m} 2 is Further preferred.

The fibers constituting the meltblown nonwoven fabric used in the present invention are preferably ultrafine fibers made of a thermoplastic elastomer. For example, polystyrene-based thermoplastic elastomer, polyolefin-based thermoplastic elastomer, polyurethane-based thermoplastic elastomer, polyester-based thermoplastic elastomer, Examples thereof include ultrafine fibers made of an ether-based thermoplastic elastomer, a polyamide-based thermoplastic elastomer, and the like. Among these, polyolefin elastomers are preferable, and polyolefin elastomers made of a copolymer of ethylene and α-olefin are particularly preferably used.
The α-olefin copolymerized with ethylene is preferably an α-olefin having 3 to 10 carbon atoms.

  When an ethylene-α-olefin copolymer is used in the present invention, the melt flow rate (MFR: based on ASTM D1238) is preferably 5 to 200 g / 10 minutes, and more preferably 10 to 100 g / 10 minutes.

  In particular, in the present invention, it is preferable to use an ethylene-octene copolymer as the ethylene-α-olefin copolymer from the viewpoint of moisture diffusibility.

  The melt blown nonwoven fabric used in the present invention extrudes heat-melted resin from nozzles having orifices arranged in a row, ejects hot air heated to the same temperature as the nozzles from slits provided in the vicinity thereof, and spins from the orifices. It is obtained by making it thin by bringing it into contact with the molten resin, and laminating it on a collection surface arranged below the nozzle to form a sheet.

Further, in order to impart a herbicidal function to the laminated sheet of the present invention, it is desirable to use a light-shielding sheet. From this point, it is preferable to arrange a light-shielding pigment on the entire surface of the sheet.
Examples of the method of disposing a light-shielding pigment on the entire surface of the sheet include a method in which a pigment having a light-shielding property is added to and dispersed in a liquid binder such as an emulsion and applied to the entire surface of the sheet with a gravure roll. .

  Moreover, it is preferable for the reason that the fastness of a pigment becomes high to use the nonwoven fabric comprised from the original fiber which contained 1-10% of carbon black with respect to the constituent fiber mass for the meltblown nonwoven fabric used as a porous film. . If the carbon black content is less than 1%, the light shielding effect is not sufficient, and the required herbicidal effect may not be obtained. On the other hand, if the content exceeds 10%, melt blow spinning may be difficult. The carbon black content is preferably 3 to 7% from the viewpoint of ensuring a balance between melt blown spinnability and light shielding properties.

  As the carbon black added to the resin constituting the melt blown nonwoven fabric, known ones such as channel black, furnace black, thermal black, acetylene black and lamp black can be used.

  A hydrophilic nonwoven fabric can be manufactured by a well-known method. For example, the above short fibers are carded to obtain a short fiber web. The short fiber web is preferably parallel or semi-random fiber orientation from the viewpoint of ensuring the lateral softness and extensibility of the laminated sheet.

As for the fabric weight of the hydrophilic nonwoven fabric obtained by said method, 15-100 g / m < ² > is preferable, More preferably, it is 20-70 g / m < ² >. When the basis weight of the hydrophilic nonwoven fabric is 100 g / m ² or more, the weight of the laminated sheet becomes heavy, which is not preferable from the viewpoint of workability.

  The method for producing the laminated sheet of the present invention is not particularly limited, and any method can be used as long as the above-described porous film and the hydrophilic nonwoven fabric can be satisfactorily adhered to each other. For example, the laminate sheet is produced by a calendering method, an embossing method, or the like. can do. Moreover, after entanglement of both by mechanical entanglement such as needle punching or water flow entanglement, the constituent fibers may be heat-sealed by heat treatment. Among these, hydroentanglement and embossing are preferably employed because they can be manufactured with high productivity.

  When embossing is performed, from the viewpoint of ensuring water permeability, the embossed pattern is preferably a point emboss rather than a continuous pattern, and the pressure-bonding area ratio is 5 to 40%, preferably 10 to 30%. If the crimping area exceeds 40%, the water permeability (speed) may be inferior. Conversely, if the area ratio is too low, the sheet strength may be insufficient.

Basis weight of the laminated sheet of the present invention thus obtained is preferably 30 to 250 g / ^{m 2,} more preferably from 40~150g / ^{m 2.} In addition, the laminated sheet of the present invention has a hydrophilic nonwoven fabric laminated on both surfaces of the porous film, from the viewpoint of ensuring better water permeability and water retention, and the advantage that the sheet strength is easily obtained and the use surface is not limited. A three-layer structure is particularly preferable.

The laminated sheet of the present invention thus obtained preferably has a water permeability of 80% or more and a transpiration rate of 3 to 15 g / day. If the water permeability is too low, water may flow on the sheet surface and water may not penetrate into the necessary part.
Also, if the transpiration is too low, soil may rot due to moisture, gas escape from the ground may be poor, roots of rapeseed trees may be spoiled, and growth may be poor. Conversely, if the transpiration is too high, water shortage may occur.
In addition, the water permeability and transpiration | evaporation said by this invention are measured by the method mentioned later.

  In addition, the laminated sheet of the present invention desirably has a light shielding property in order to prevent weed germination, and specifically has a light shielding rate of 90% or more, preferably 95% or more. The light shielding rate referred to in the present invention is measured by the method described later.

  The laminated sheet of the present invention preferably has a stiffness of 130 mm or less, and more preferably 100 mm or less, from the viewpoint of ease along the soil.

  In addition, the laminated sheet of the present invention may have a 10% elongation stress of 34 N / 5 cm or less from the viewpoint that the laminated sheet is deformed by walking on the laminated sheet after laying and becomes easier to follow along the soil. Preferably, it is 20 N / 5 cm or less.

  The laminated sheet of the present invention is most preferably obtained from a viewpoint of productivity and product performance by a method of heat-bonding a melt-blown nonwoven fabric and a hydrophilic nonwoven fabric obtained from a semi-random web or a parallel web.

  The laminated sheet of the present invention is useful as a sheet to be laid for the purpose of water retention and grass protection in soil with large irregularities, such as cultivation grounds such as orchards and vegetable gardens, furrows, passages, etc., but is not limited thereto, It can also be applied to uses for the purpose of preventing grass on the surface of the surface or around the house. In addition, the laminated sheet of the present invention is excellent in water permeability and water absorption, and appropriately emits moisture. Therefore, when used as the above-described various sheets, there is an advantage that the temperature change of the covered ground is small. .

  EXAMPLES Hereinafter, although an Example demonstrates this invention more concretely, this invention is not limited to these Examples at all. In addition, each physical property value in a present Example was measured with the following method.

(Weight, thickness, density)
The thickness (mm) corresponding to one sample was calculated by stacking four samples cut into 30 cm squares and setting the thickness measured under a load of 12 gf / cm ² to ¼. Furthermore, the mass of the same sample (30 cm square × 4 sheets) was measured to determine the basis weight (g / m ² ) per sheet. Further, the apparent density (g / cm ³ ) was obtained by dividing the basis weight by the thickness.

(Flexibility)
In accordance with JIS L1096 stiffness / softness A method (45 ° cantilever method), the stiffness in the transverse direction of the sheet was measured.

(Stress at 10% lateral elongation)
According to JIS L1913 tensile strength and elongation, the tensile strength was measured when the sample was stretched 10% by pulling in the transverse direction of the sheet.

(Average fiber diameter)
Using a scanning electron microscope (SEM), take a photograph of the surface of the nonwoven fabric magnified 1000 times, draw two diagonal lines on this photograph, and calculate the value obtained by converting the thickness of the fiber that intersects the diagonal line into a magnification. Using. And the average value of 50 of these fibers was made into the average fiber diameter.

(Average number of openings in porous film)
Using a microscope, a photograph was taken that had been magnified to such a magnification that the holes on the surface of the porous film could be clearly observed, and the number of holes in the photograph was counted. The average number of apertures was obtained from the average value per unit area of 10 porous films.

(Average pore diameter of porous film)
Using a microscope, a photograph was taken that was enlarged to such a magnification that the pores on the surface of the porous film could be clearly observed, and the pore area in this photograph was obtained. Next, the total hole area was divided by the number of holes, and the diameter when the hole was assumed to be a perfect circle was calculated from the area per hole obtained. The average pore diameter was obtained from the average value per unit area of 10 porous films.

(Light shielding)
The light shielding rate (%) was measured according to JIS L1906 5.10 (light shielding property and light projecting property). The illuminance of the light source was adjusted to 1000 lx.

(Water permeability)
The water permeability was measured by the method shown in FIG.
First, a 30 cm × 62 cm grid net 1 (net diameter 1 mm diameter, hole interval 3.5 cm) was arranged at an angle of 30 ° with respect to the ground. Next, Sample 2 (laminated sheet) 30 cm wide × 40 cm long was placed on the lattice net. At this time, the receiving tank (I) 3 was installed immediately below the sample, and the receiving tank (II) 4 was installed in the vicinity of the portion where the lattice net and the ground contact.
A beaker 5 containing 500 g of water was prepared, water was poured from a position 3 cm high from the upper end of the sample over 20 seconds, and then left for 1 minute.
Next, the amount of water that fell into the receiving tank (I) (water permeability; g), the amount of water absorbed into the sample (water retention amount; g), and the amount of water that fell into the receiving tank (II), that is, it did not fall into the receiving tank (I), The amount of water that flowed without being absorbed (flow amount; g) was also measured.
A value (%) obtained by dividing the total amount of water permeability and water retention by 500 g was defined as water permeability (water permeability).
The same measurement was performed three times, and the results were recorded for each. The interval between each measurement was 5 minutes.
The higher the water permeability value, the better the water permeability.

(Transpiration)
After putting 300 g of water in a 500 cc beaker (diameter 10 cm) and covering a 15 cm × 15 cm sample (laminated sheet) so as to cover the beaker spout, the vicinity of the spout was bound with a rubber band and the mass was measured.
This beaker was placed in a thermo-hygrostat (“Platinum Rainbow PR-1S” manufactured by Tabai Espec Co., Ltd.), and the mass was measured every 24 hours under the conditions of 40 ° C. and 60% humidity to determine the amount of water evaporation. The measurement time was 5 days (120 hours), and the amount of evaporated water was divided by the measurement time to obtain transpiration.
Transpiration (g / day) = water evaporation (g) / 5 days The transpiration was 43 g / day when measured without covering the sample in a beaker.

The following were prepared as raw materials.
[Fiber A]: Polyvinyl alcohol fiber (manufactured by Kuraray Co., Ltd., “Kuraron K-II EQ0”) 1.7 dtex × 38 mm
[Fiber B]: Polyethylene terephthalate fiber (using durable hydrophilic fiber oil, manufactured by Teijin Ltd., “TT04L”) 1.7 dtex × 44 mm
[Fiber C]: Polyethylene terephthalate fiber (using hydrophobic fiber oil, manufactured by Teijin Ltd., “TT02T”) 1.7 dtex × 51 mm
[Fiber D]: Heat-sealable fiber (core: polyethylene terephthalate / sheath: core-sheath type composite fiber which is a copolyester, sheath component melting point 110 ° C., manufactured by Teijin Ltd., “TT04C2”) 2.2 dtex × 51 mm
[Fiber E]: Viscose rayon fiber (Corona, manufactured by Daiwabo Rayon Co., Ltd.) 1.7 dtex × 40 mm
[Melt blown nonwoven fabric A] A melt blown nonwoven fabric having an average fiber diameter of 7 μm and a basis weight of 20 g / m ² was produced using an ethylene-octene copolymer (manufactured by Dow Chemical Co., Ltd., “engage”, MFR: 30 g / 10 min). In addition, carbon black was added to the copolymer as a pigment so as to be contained in 3% by mass in the constituent fibers of the melt blown nonwoven fabric.
[Melt blown nonwoven fabric B]: A melt blown nonwoven fabric having a basis weight of 20 g / m ² was produced under the same conditions as in the melt blown nonwoven fabric A. Carbon black was not added to the constituent fibers of the melt blown nonwoven fabric.
[Binder A]: Toyo Ink Co., Ltd. (WS-Black K-7) was mixed with acrylic binder (FX-582) manufactured by Nippon Carbide Co. at a mass ratio of 15:85 to prepare a mixed solution.

Example 1
40% by mass of polyvinyl alcohol fiber (fiber A), 40% by mass of polyethylene terephthalate fiber (fiber B), 20% by mass of heat-fusible fiber (fiber D), and a semi-random web having a basis weight of 30 g / m ² Manufactured.
Next, after laminating the obtained webs on both sides of the melt-blown nonwoven fabric (melt-blown nonwoven fabric A), a water flow was sprayed on the laminate to perform an entanglement treatment. In addition, the hydroentanglement process used the nozzle in which the orifice of 0.1 mm in diameter was provided for every 0.6 mm space | interval in the width direction of the web, and was entangled by injecting on both sides with water pressure 3MPa and 5MPa, respectively.
After the entanglement treatment, heat treatment was performed at 130 ° C. with a cylinder dryer to obtain a laminated sheet of the present invention in which the melt-blown nonwoven fabric was made into a porous film and at the same time laminated with both sides hydrophilic nonwoven fabric.
Only the porous film (melt-blown nonwoven fabric after heat treatment) was taken out from the obtained laminated sheet and observed with a microscope. As a result, the average number of pores was about 13,500 / cm ² and the average pore size was 47 μm.
Other results are shown in Tables 1-3.
As a result of laying the obtained laminated sheet in the ridge shown in Fig. 2 and observing the progress of three months from April to June, the alongside to the soil is good and weed growth is almost seen in the laying range. There wasn't.

(Example 2)
The same web and porous film as those used in Example 1 were prepared, and three-layer lamination and hydroentanglement treatment were performed.
Next, 3.2 g / m ^{2 of} an acrylic binder preparation liquid (Binder A) was applied to both surfaces of the sheet with a gravure roll.
Subsequently, it dried at 130 degreeC with the cylinder dryer, and obtained the laminated sheet of this invention which laminated | stacked the hydrophilic nonwoven fabric whose surface is black on both surfaces of a porous film.
Only the porous film (melt blown nonwoven fabric after heat treatment) was taken out from the obtained laminated sheet and observed with a microscope. As a result, the average number of pores was about 14,200 holes / cm ² and the average pore size was 51 μm. .
Other results are shown in Tables 1-3.
As a result of laying the obtained laminated sheet between the ridges shown in FIG. 2 and observing the progress of three months from April to June, as in Example 1, the alongness to the soil is good and within the laying range. There was hardly any weed growth.

(Example 3)
40% by mass of viscose rayon fiber (fiber E), 40% by mass of polyethylene terephthalate fiber (fiber B), 20% by mass of heat-fusible fiber (fiber D), and a semi-random web with a basis weight of 30 g / m ² Manufactured.
Next, after laminating the obtained webs on both sides of the melt-blown nonwoven fabric (melt-blown nonwoven fabric A), a water flow was sprayed on the laminate to perform an entanglement treatment. In addition, the hydroentanglement process used the nozzle in which the orifice of 0.1 mm in diameter was provided for every 0.6 mm space | interval in the width direction of the web, and was entangled by injecting on both sides with water pressure 3MPa and 5MPa, respectively.
After the entanglement treatment, drying was performed at 130 ° C. with a cylinder dryer to obtain a laminated sheet of the present invention in which hydrophilic nonwoven fabrics were laminated on both surfaces of a melt blown nonwoven fabric.
Only the porous film (melt blown nonwoven fabric after heat treatment) was taken out from the obtained laminated sheet and observed with a microscope. As a result, the average number of pores was about 13,900 / cm ² and the average pore size was 58 μm. . Other results are shown in Tables 1-3.
As a result of laying the obtained laminated sheet in the ridge shown in FIG. 2 and observing the progress of three months from April to June, the layability to the soil is good and laid as in Examples 1 and 2. Almost no weed growth was observed within the range.

Example 4
After using the same raw material fiber as that used in Example 1 to produce a semi-random web at the same mixing rate, a water stream was jetted to perform an entanglement treatment. In addition, the hydroentanglement treatment uses a nozzle in which an orifice having a diameter of 0.1 mm is provided at intervals of 0.6 mm in the width direction of the web, and is entangled by spraying the front and back at a water pressure of 3 MPa and 5 MPa, respectively, and has a basis weight of 30 g / m. ² hydroentangled nonwoven fabric was obtained.
On the other hand, the meltblown nonwoven fabric (meltblown nonwoven fabric A) used in Example 1 was prepared, and the water-entangled nonwoven fabric obtained on both sides of this meltblown nonwoven fabric was laminated to obtain a laminate.
The thus obtained laminate, heat embossing roll with (bonding area ratio of 26%, the point area 0.51 cm ² / number, number of points 51 pieces / cm ^2), roll temperature 130 ° C., the linear pressure 30kg / cm Thus, a heat embossing treatment was performed to obtain a laminated sheet of the present invention in which a hydrophilic nonwoven fabric was laminated on both sides of a melt blown nonwoven fabric.
From the obtained laminated sheet, only the porous film (melt blown nonwoven fabric after heat treatment) was taken out and observed with a microscope. As a result, the average number of pores was about 14,100 / cm ² and the average pore size was 50 μm.
Other results are shown in Tables 1-3.
As a result of laying the obtained laminated sheet between the ridges shown in FIG. 2 and observing the progress of three months from April to June, as with Examples 1 to 3, the alongness to the soil is good and laid. Almost no weed growth was observed within the range.

(Comparative Example 1)
80% by mass of polyethylene terephthalate fiber (fiber C) and 20% by mass of heat-fusible fiber (fiber C) were mixed to produce a semi-random web having a basis weight of 30 g / m ² .
Next, after laminating the obtained webs on both sides of the melt-blown nonwoven fabric (melt-blown nonwoven fabric A), a water stream was sprayed on the laminate to perform an entanglement treatment. In addition, the hydroentanglement process used the nozzle in which the orifice of 0.1 mm in diameter was provided for every 0.6 mm space | interval in the width direction of the web, and was entangled by injecting on both sides with water pressure 3MPa and 5MPa, respectively.
After the entanglement treatment, drying was performed at 130 ° C. with a cylinder dryer to obtain a laminated sheet.
Only the porous film (melt blown nonwoven fabric after heat treatment) was taken out from the obtained laminated sheet and observed with a microscope. As a result, the average number of pores was about 13,200 / cm ² and the average pore size was 55 μm.
Other results are shown in Tables 1-3.
The obtained laminated sheet was laid between the ridges shown in FIG. 2 and observed for three months from April to June. As a result, water permeability during irrigation and rain was extremely poor.

(Comparative Example 2)
40% by mass of polyvinyl alcohol fiber (fiber A), 40% by mass of polyethylene terephthalate fiber (fiber B), 20% by mass of heat-fusible fiber (fiber D), and a semi-random web with a basis weight of 80 g / m ² Manufactured. Subsequently, a water flow was sprayed on this web, and the entanglement process was performed. In addition, the hydroentanglement process used the nozzle in which the orifice of 0.1 mm in diameter was provided for every 0.6 mm space | interval in the width direction of the web, and was entangled by injecting on both sides with water pressure 3MPa and 5MPa, respectively.
After the entanglement treatment, the sheet was dried at 130 ° C. with a cylinder dryer to obtain a sheet. The results are shown in Tables 1-3.
As a result of laying the obtained laminated sheet in the ridge shown in FIG. 2 and observing the progress of three months from April to June, the soil moisture after the transpiration was early and the control area where no laminated sheet was laid There was almost no difference. In addition, the growth of weeds was confirmed throughout the test area one month after laying.

(Comparative Example 3)
A hydrophilic nonwoven fabric and a melt blown nonwoven fabric similar to those used in Example 1 were prepared, and three-layer lamination and hydroentanglement treatment were performed.
Next, after laminating the obtained webs on both sides of the melt-blown nonwoven fabric (melt-blown nonwoven fabric B), a water flow was sprayed on the laminate to perform an entanglement treatment. In addition, the hydroentanglement process used the nozzle in which the orifice of 0.1 mm in diameter was provided for every 0.6 mm space | interval in the width direction of the web, and was entangled by injecting on both sides with water pressure 3MPa and 5MPa, respectively.
After the entanglement treatment, drying was performed at 130 ° C. with a cylinder dryer to obtain a laminated sheet of the present invention. Only the porous film (melt blown nonwoven fabric after heat treatment) was taken out from the obtained laminated sheet and observed with a microscope. As a result, the average number of pores was about 13,300 / cm ² and the average pore size was 51 μm.
Other results are shown in Tables 1-3.
As a result of laying the obtained laminated sheet between the ridges shown in FIG. 2 and observing the progress of 3 months from April to June, the growth of weeds was observed throughout the test area in the same manner as in Comparative Example 2 in 1 month after laying. confirmed.

(Comparative Example 4)
40% by mass of polyvinyl alcohol fiber (fiber A), 40% by mass of polyethylene terephthalate fiber (fiber B), and 20% by mass of heat-fusible fiber (fiber D) to produce a cross web with a basis weight of 30 g / m ² did.
Next, after laminating the obtained hydrophilic nonwoven fabric on both surfaces of the meltblown nonwoven fabric (meltblown nonwoven fabric A), a water stream was sprayed on the laminate to perform an entanglement treatment. In addition, the hydroentanglement process used the nozzle in which the orifice of 0.1 mm in diameter was provided for every 0.6 mm space | interval in the width direction of the web, and was entangled by injecting on both sides with water pressure 3MPa and 5MPa, respectively.
After the entanglement treatment, drying was performed at 130 ° C. with a cylinder dryer to obtain a laminated sheet of the present invention. Only the porous film (melt blown nonwoven fabric after heat treatment) was taken out from the obtained laminated sheet and observed with a microscope. As a result, the average number of pores was about 14,000 holes / cm ² and the average pore size was 56 μm.
Other results are shown in Tables 1-3.
The resulting laminated sheet was laid between the furrows shown in FIG.

The schematic diagram which shows the apparatus for measuring the water permeability in this invention. The schematic diagram of the furrow which performed the evaluation test of the lamination sheet in this invention.

Explanation of symbols

1: Grid net 2: Laminated sheet 3: Receiving tank (I)
4: Receiving tank (II)
5: Beaker 6: Laminated sheet 7: Fixing jig 8: Samurai 9: Crop

Claims (8)

A laminated sheet obtained by laminating a hydrophilic nonwoven fabric and a porous film, wherein at least one of the hydrophilic nonwoven fabric and / or the porous film contains a light-shielding pigment, and the hydrophilic nonwoven fabric is a semi-random web Or the nonwoven fabric obtained from the parallel web, Comprising: The air permeability of this laminated sheet is 10-500 cc / cm < ² > * sec, The laminated sheet characterized by the above-mentioned. The laminated sheet according to claim 1, wherein the hydrophilic non-woven fabric contains 6 to 100% of polyvinyl alcohol fiber. The laminated sheet according to claim 1, wherein the light shielding ratio is 90% or more. The laminated sheet according to claim 1, wherein the porous film is made of a polyolefin resin. It is a laminated sheet of Claim 1, Comprising: Both surfaces of the porous film are laminated | stacked with the said hydrophilic nonwoven fabric, The laminated sheet characterized by the above-mentioned. The laminated sheet according to claim 1, wherein the sheet has a lateral bending resistance of 130 mm or less. The laminated sheet according to claim 1, wherein a stress at 10% elongation in the transverse direction of the sheet is 34 N / 5 cm or less. The method for producing a laminated sheet according to claim 1, wherein the melt blown nonwoven fabric and a hydrophilic nonwoven fabric obtained from a semi-random web or a parallel web are heat-bonded.

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