JP3232837U - Weed control sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a weed-proof sheet which is strong, lightweight, thin, and has excellent durability and weather resistance. SOLUTION: This is a weed-proof sheet made of a mesh body, wherein the mesh body is based on a low melting point thermoplastic polymer, and a plurality of high melting point thermoplastics having a higher melting point than the low melting point thermoplastic polymer in the mother body. It is made of fiber reinforced plastic in which fibers made of polymer are present. The fibers formed of the refractory thermoplastic polymer are continuous fibers. [Selection diagram] Fig. 1

Description

The present invention relates to a weed-proof sheet.

As a weed-proof sheet, for example, in Patent Document 1, a non-woven fabric having a light-shielding property and the woven fabric composed of inorganic fibers and having a flame-retardant synthetic resin layer on at least one surface are laminated. Is listed. The non-woven fabric is a needle punch felt non-woven fabric, and the non-woven fabric composed of inorganic fibers is woven using at least one roving yarn selected from the group consisting of glass fibers, carbon fibers and basalt fibers. is there. The flame-retardant synthetic resin layer is composed of a polymer selected from the group containing an ethylene-vinyl acetate copolymer, polyvinyl chloride, thermoplastic polyurethane and a mixture thereof.

JP-A-2019-41629

An object of the present invention is to improve such a known weed control sheet to obtain a strong, lightweight and thin weed control sheet having excellent durability and weather resistance.

In order to achieve this object, the weed-proof sheet of the present invention is a weed-proof sheet made of a mesh body, and the mesh body is based on a low melting point thermoplastic polymer, and the low melting point thermoplastic polymer is contained in the mother body. It is also characterized in that it is made of a fiber reinforced plastic in which fibers formed of a plurality of high melting point thermoplastic polymers have a high melting point, and the fibers made of the high melting point thermoplastic polymer are continuous fibers.

According to the weed-proof sheet of the present invention, it is preferable that both the high-melting-point thermoplastic polymer and the low-melting-point thermoplastic polymer are composed of a polyamide-based polymer or a polyester-based polymer.

According to the weed-proof sheet of the present invention, it is preferable that the mesh body has a plain weave structure in which fibers formed of a plurality of refractory thermoplastic polymers existing in the mother body are arranged in warp threads and weft threads. is there.

According to the weed-proof sheet of the present invention, it is preferable that the mesh size is 50 to 1000 μm.

According to the weed-proof sheet of the present invention, it is preferable that ^{the basis weight is 100 to 400 g / m 2.}

According to the weed-proof sheet of the present invention, it is preferable that it is colored black.

According to the weed-proof sheet of the present invention, a mesh body formed of a fiber reinforced plastic having a low melting point thermoplastic polymer as a base and having fibers formed of a plurality of high melting point thermoplastic polymers in the base body. Since the fibers that are composed and formed of the high melting point thermoplastic polymer are continuous fibers, the mesh eyes are not spread by weed buds, etc., so that a good weed control effect can be exhibited and the fiber is low. Since the required strength can be obtained even with the texture, it can be made thin and lightweight. Further, since a plurality of fibers formed of the high melting point thermoplastic polymer are present in the mother body based on the low melting point thermoplastic polymer having a lower melting point than the high melting point thermoplastic polymer, the fibers themselves are not easily damaged. Therefore, it has excellent durability and weather resistance.

It is an enlarged view of the weed-proof sheet of embodiment of this invention. It is a figure which further enlarged the main part in FIG. It is a figure which shows the state of the sheet laying site for observing the growth state of the weed using the weed-proof sheet of embodiment of this invention. It is a figure which shows the situation immediately after laying the weed-proof sheet at the site of FIG. It is a figure which shows the situation at a later date than FIG. It is a figure which shows the situation at a later date than FIG. It is a figure which shows the situation at a later date than FIG. It is a figure which shows the situation at a later date than FIG.

As shown in FIGS. 1 and 2, for example, the weed-proof sheet according to the embodiment of the present invention is a woven fabric woven with a multifilament yarn made of composite heat-sealing fibers and then heat-treated. It is composed of a mesh body composed of the above. In the examples of FIGS. 1 and 2, multifilament yarns made of composite thermoplastic fibers are arranged on warp yarns and weft yarns to obtain a mesh-like plain fabric, and then the low melting point of each thermoplastic fiber is obtained. By melting the thermoplastic polymer, they are integrated with each other to form a base body, and the presence of fibers formed of the high melting point thermoplastic polymer in the base body constitutes a sheet by a mesh body made of fiber reinforced plastic. There is. In the mesh sheet of FIGS. 1 and 2, the mesh size (distance between the center lines of the warp threads and the weft threads) is about 1 mm, and the mesh opening (top-bottom width or left and right of the hole formed by the intersection of the warp threads and the weft threads). Width), that is, the mesh size is about 0.6 mm (600 μm). The mesh size is preferably 50 to 1000 μm. In addition to this, the sheet can be composed of knitted fabric or non-woven fabric.

Both the warp yarn 1 and the weft yarn 2 are mulch made of a continuous composite heat-sealing fiber in which a high melting point thermoplastic polymer and a low melting point thermoplastic polymer having a lower melting point than the high melting point thermoplastic polymer are composited. It is formed by heat-treating the filament yarn, and is made of a fiber-reinforced plastic in which a plurality of fibers formed of the high-melting-melting thermoplastic polymer are present in a mother body in which the low-melting-melting thermoplastic polymer is melted and integrated. It is formed. Then, at each intersection of the warp 1 and the weft 2, the low melting point thermoplastic polymer is melted and solidified by the above heat treatment to become a base material, and at this intersection 3, the high melting point heat is also contained in the base body made of the low melting point thermoplastic polymer. There are multiple fibers formed of a plastic polymer. The spacing between the warp threads 1 and the spacing between the weft threads 2 in the mesh may be less than or equal to the size of the buds so that buds such as weeds cannot pass through. Therefore, this interval is preferably set to about 1 mm as described above.

At each intersection of the warp 1 and the weft 2, the low melting point thermoplastic polymer is melted and solidified to form an integrated base body, and a plurality of continuous fibers formed of the high melting point thermoplastic polymer are present in this base body. By doing so, it is possible to reliably prevent the mesh from shifting, that is, the eyes from opening to the extent that buds such as weeds can pass through.

A multifilament yarn made of composite heat-sealing fibers for obtaining a mesh body is formed by converging a plurality of composite heat-sealing fibers and has flexibility before heat treatment, so that it is woven. It's easy to do. The multifilament yarn may be untwisted or twisted. Furthermore, when only the low melting point thermoplastic polymer is melted and solidified by heat treatment, the high melting point thermoplastic polymer maintains the fiber morphology without melting even when heated, so that the melted and solidified low melting point thermoplastic polymer is maintained. It exists in the form of continuous fibers in the base of the thermoplastic polymer, that is, the continuous fibers of the high melting point thermoplastic polymer are covered with the low melting point thermoplastic polymer, which improves the strength and rigidity of the mesh body. Further, at the intersection of the warp and the weft, the whole is firmly integrated by melting and solidifying the low melting point thermoplastic polymer constituting each multifilament yarn, and the intersection can be firmly fused and integrated. The reason for adopting the multifilament yarn in the present invention is that in the case of the monofilament yarn, since the warp and the weft are formed by one filament, the diameter of one filament is large and it is not as flexible as the multifilament. In addition, at the intersection of the warp and weft, only the contact points between the monofilaments are heat-bonded and integrated by applying heat, so the multifilament is more firmly fused and integrated as a whole even at the intersection, resulting in a fiber reinforced plastic. Because.

The fineness of the single fiber of the composite heat-sealing fiber constituting the multifilament yarn is preferably about 5 to 12 decitex, and the number of filaments is preferably about 50 to 200. For example, a multifilament yarn of 1100 decitex / 96f is preferable. Can be used for. The fineness of the multifilament yarn is preferably 280 to 1670 decitex from the viewpoint of the strength of the weed control sheet.

Examples of the composite form of the composite heat-sealing fiber include a core-sheath type heat-sealing fiber in which a low-melting-melting thermoplastic polymer is arranged in a sheath portion and a high-melting-melting thermoplastic polymer is arranged in a core portion. In addition, side-by-side type heat-sealing fibers in which a low-melting-point thermoplastic polymer and a high-melting-point thermoplastic polymer are arranged in half are mentioned. The mass ratio of the low melting point thermoplastic polymer to the high melting point thermoplastic polymer in the composite heat-sealing fiber is determined by, for example, considering the required hardness as a weed-proof sheet, durability, fusion integrity, and the like. The ratio of the high melting point thermoplastic polymer to the low melting point thermoplastic polymer is preferably 2/8 to 8/2, more preferably 5/5 to 3/1, and further preferably 3/1.

The low-melting-point thermoplastic polymer and the high-melting-point thermoplastic polymer in the composite heat-sealing fiber need to have a silk-reeling property by melt spinning. Further, considering the fusion integrity at the intersection of the warp 1 and the weft 2, it is preferable that both polymers are polymers of the same type. Examples thereof include polyester-based polymers, polyamide-based polymers (nylon), polyolefin-based polymers, polybutyral-based polymers, polyacrylic-based polymers, polyethylene-vinyl acetate copolymers, and polyurethane polymers. In particular, both polymers are polyamide-based polymers in that when the weed-proof sheet is partially bent and installed depending on the installation location, it is easy to bend and adapt to the shape according to the installation location. It is preferable that both polymers are polyester-based polymers in that they are excellent in strength and rigidity, are also excellent in hardness, and have weather resistance.

Specific preferable combinations of the low melting point thermoplastic polymer and the high melting point thermoplastic polymer are low melting point polyester and high melting point polyester, low melting point polypropylene and high melting point polypropylene, and polyethylene in consideration of compatibility and fusion integrity of the two. And polypropylene, low melting point nylon and high melting point nylon, and the like.

The strength, elongation, etc. of the composite heat-sealing fiber are not particularly limited as long as the object of the present invention is achieved.

The cross-sectional shape of the composite heat-sealing fiber may be any of a round cross section, a deformed cross section, a hollow cross section, and the like as long as the desired performance is not impaired.

The low melting point thermoplastic polymer and the high melting point thermoplastic polymer in the composite heat-sealing fiber are independently heat stabilizers, crystal nucleating agents, matting agents, pigments, light-resistant agents, weather-resistant agents, lubricants, and oxidations. Additives such as inhibitors, antibacterial agents, fragrances, plasticizers, dyes, surfactants, flame retardants, surface modifiers, various inorganics, and organic polymers may be contained. In particular, in the weed-proof sheet of the present invention, it is preferable that the weed-proof sheet, that is, the warp 1 and the weft 2 are colored black for the reason of maintaining long-term durability. For coloring with black, carbon black may be contained in either a high melting point thermoplastic polymer or a low melting point thermoplastic polymer to obtain a dyed fiber.

The core-sheath type heat-sealing fiber as a composite type heat-sealing fiber is available as a commercially available product. For example, "MELSET (registered trademark)" manufactured by Unitika Ltd. can be used.

As a composite heat-sealing fiber, two or more types of composite heat-sealing properties having different physical properties such as melting point of low melting point thermoplastic polymer and high melting point thermoplastic polymer, mass ratio, fineness, strength and elongation of both. Fibers may be used.

The melting point of the base low melting point thermoplastic polymer is preferably 20 ° C. or more lower than the melting point of the high melting point thermoplastic polymer as a fiber forming component. With such temperature characteristics, there is an advantage that the physical properties of the high melting point thermoplastic polymer are not affected even if it is subjected to heat treatment, and the fiber morphology can be well maintained. The melting point of the low melting point thermoplastic polymer is preferably in the range of 80 to 160 ° C. in consideration of processability, various physical properties and the like. When the low melting point thermoplastic polymer does not have a definite melting point, the softening point of the low melting point thermoplastic polymer can be regarded as the melting point.

Specifically, as the core-sheath type composite heat-sealing fiber, a high melting point polyester having a melting point of 240 ° C. or higher (for example, polyethylene terephthalate) is arranged in the core portion, and a low melting point having a melting point of 110 to 200 ° C. is arranged. Core-sheath type polyester fiber in which the copolymerized polyester of No. 1 is arranged in the sheath portion, and a core in which a high melting point polyamide having a melting point of 180 ° C. or higher is arranged in the core portion and a low melting point polyamide having a melting point of 80 to 150 ° C. is arranged in the sheath portion. Sheath-type polyamide fibers are preferably used.

As a method for melting the low melting point thermoplastic polymer which is the base material, heat treatment can be mentioned. The heat treatment is a process of maintaining an atmospheric temperature higher than the melting point of the low melting point thermoplastic polymer. As a result, in the composite heat-sealing fiber, the low melting point thermoplastic polymer is melted and integrated to form a base body, and can be integrated even at the intersection of the warp 1 and the weft 2 shown in FIGS. 1 and 2. .. Further, by uniformly melting and solidifying the low melting point thermoplastic polymer, the fibers formed by a plurality of high melting point thermoplastic polymers (core portion in the case of core-sheath type heat-sealing fibers) are uniformly covered. , Fibers formed of a high melting point thermoplastic fiber polymer can be uniformly present in the mother body, resulting in a uniform mesh body having high mechanical strength.

When two or more types of composite filaments containing different types of low melting point thermoplastic polymers are used, the melting point of the low melting point thermoplastic polymer having the highest melting point is used as a reference, and the melting point of the low melting point thermoplastic polymer having the highest melting point is used as a reference. The heat treatment may be performed at an atmospheric temperature higher than the melting point. The ambient temperature during the heat treatment is preferably a temperature higher than the melting point of the low melting point thermoplastic polymer and lower than the melting point of the high melting point thermoplastic polymer. If the atmospheric temperature is too high, not only is it disadvantageous in terms of cost, but also the refractory thermoplastic polymer is damaged by heat, resulting in a decrease in the strength of the warp 1 and the weft 2. The atmospheric temperature is preferably MpL + 5 ° C. or higher and less than MpL + 20 ° C. when the melting point of the low melting point thermoplastic polymer is expressed as MpL.

The time for applying the heat treatment may be any time as long as the low melting point thermoplastic polymer is sufficiently melted. However, if the heat treatment time is too long, not only is it disadvantageous in terms of cost, but also the refractory thermoplastic polymer is damaged by heat, resulting in a decrease in the strength of the fiber as a whole. Therefore, the heat treatment time is preferably 30 seconds to 5 minutes, more preferably 1 minute to 3 minutes. The heating method for performing the heat treatment is not particularly limited, but a well-known means such as an iron, a hot air welder, a hot air dryer, and a tenter machine can be used.

The mesh-shaped weed-proof sheet thus obtained preferably has a basis weight of 100 to 400 g / m ² . When the basis weight is in this range, it is lightweight and thin, and therefore the handleability can be improved.

Further, in the weed-proof sheet of the present invention, as described above, the continuous fibers of the high-melting-point thermoplastic polymer are composed of the fiber-reinforced plastic in the state of being present in the mother body made of the low-melting-point thermoplastic polymer, so that the warp 1 and the weft No. 2 has an advantage that the surface is smooth, so that it is hard to get dirty and water is hard to adhere to it, so that algae are hard to grow and the seeds of weeds that have flown are hard to stick to it. As a result, the appearance is good and a further weed control effect can be exhibited. It can also exhibit resistance to dirt due to the fact that it is difficult for water to adhere. In addition, since it has a mesh structure, it is difficult for noise to be generated when raindrops land during rainfall, and it is possible to expect a soundproofing effect. Since it has a mesh structure, it is possible to ensure air permeability and water permeability to soil and the like.

Various physical properties in the following Examples and Comparative Examples were evaluated as follows.

(Mesh size)
With a KEYENCE microscope VHX-900, the weed-proof sheet was magnified and observed at a magnification of 200 times, and the vertical and horizontal lengths of 10 arbitrary openings (mesh) were measured using the measurement function. The mesh size of the weed control sheet was obtained by calculating the average value.

(Tensile strength, elongation)
According to the JIS L 1096 8.14.1 A method, a tensile test was performed using an Autograph AG-1 manufactured by Shimadzu Corporation at a width of 30 mm, a grip interval of 200 mm, and a tensile speed of 200 mm / min to obtain a weed-proof sheet. Tensile strength and elongation were measured.

(Tearing strength)
According to the JIS L 1096 8.17.1 A1 method, the tear strength of the weed control sheet was measured using the Autograph AG-1 manufactured by Shimadzu Corporation.

(Weed proof)
The weed-proof sheet was cut with scissors so as to have a size of 400 mm × 300 mm square, and two sheets were prepared. The 300 mm sides are overlapped by 50 mm, and the sheets are joined together using a 100 mm wide adhesive tape (product name: KUSA GR) manufactured by Kanbo Pras Corporation so that all the overlapped parts are covered, and 700 mm x 300 mm. It was used as a corner weed control sheet. A weed-proof sheet was laid on the ground where weeds were growing, and stainless steel nails having a length of 100 mm were struck at the four corners of the weed-proof sheet, and the weed-proof sheet was laid on the ground. Weed growth was observed for about 4 months from July 18th to November 23rd, 2020 when the weed control sheet was laid.

Example: A polyester-based core-sheath composite type black original multifilament yarn, Unitika's Melset (product name: CM27B), with 1100 decitex tex96 filament, was twisted at S-120 T / m. Then, using this twisted yarn, a woven fabric was obtained by weaving with a plain weave structure having a warp yarn density of 21 yarns / inch and a weft yarn density of 20 yarns / inch. The obtained woven fabric was heat-treated with a pin tenter at 180 ° C. for 2 minutes to obtain a weed-proof sheet made of a mesh body having a width of 2060 mm.

Table 1 shows various physical characteristics of the obtained weed control sheet.

Further, FIG. 3 shows the situation of the ground used for the test of the weed control sheet obtained above on July 18, 2020. As shown in FIG. 4, the weed control sheet of the above embodiment is shown on the ground. 4 was laid on the same day. FIG. 5 shows the situation on August 29, the same year, FIG. 6 shows the situation on September 26, the same year, FIG. 7 shows the situation on October 31, the same year, and FIG. 8 shows the situation on November 23, the same year.

As is clear from FIGS. 4 to 8, weeds 5 were observed to grow in the areas where the weed control sheet 4 was removed, but weeds and the like were not grown in the area where the weed control sheet 4 was laid. That is, in the area where the weed control sheet 4 was laid, weeds did not penetrate from below, and the growth of weeds could be suppressed satisfactorily.

Comparative Example A commercially available non-woven fabric weed-proof sheet (manufactured by DuPont, product name: Zaburn 240G) was evaluated for the above-mentioned physical properties excluding weed-proof properties. As a result, the elongation was good as compared with the above-mentioned weed-proof sheet of the embodiment of the present invention, but the tensile strength and the tear strength were inferior to those of the weed-proof sheet of the embodiment of the present invention.

On the contrary, from this, the weed-proof sheet of the embodiment of the present invention is superior in tensile strength and tear strength as compared with the known non-woven fabric weed-proof sheet, and has low elongation, so that it is dimensionally stable. Was confirmed to be good.

1 Warp 2 Weft 3 Melted and solidified part

Claims (6)

A weed-proof sheet made of a mesh body, wherein the mesh body is based on a low melting point thermoplastic polymer, and a plurality of high melting point thermoplastic polymers having a higher melting point than the low melting point thermoplastic polymer are contained in the mother body. A weed-proof sheet made of a fiber-reinforced plastic in which the formed fibers are present, and characterized in that the fibers formed of a refractory thermoplastic polymer are continuous fibers. The weed-proof sheet according to claim 1, wherein the high-melting-point thermoplastic polymer and the low-melting-point thermoplastic polymer are both composed of a polyamide-based polymer or a polyester-based polymer. The weed control according to claim 1 or 2, wherein the mesh body has a plain weave structure in which fibers formed of a plurality of refractory thermoplastic polymers existing in the mother body are arranged in warp threads and weft threads. Sheet. The weed-proof sheet according to any one of claims 1 to 3, wherein the mesh size is 50 to 1000 μm.
The weed-proof sheet according to any one of claims 1 to 4, wherein the basis weight is 100 to 400 g / m ^2. The weed-proof sheet according to any one of claims 1 to 5, which is colored black.

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