JP2017063643A - Volcanic ash removal sheet for agricultural crops - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a volcanic ash removal sheet for agricultural crops that combines volcanic ash collectability and air permeability.SOLUTION: The volcanic ash removal sheet for agricultural crops has a surface layer 11, an intermediate layer 12 and a back layer 13. The surface layer 11 and the back surface layer 13 are composed of a spunbond nonwoven fabric. The intermediate layer 12 is composed of a melt blown nonwoven fabric.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a volcanic ash repellent sheet for agricultural products.

  In Japan, where there are many active volcanoes, there is a concern that ash falls on the agricultural land near the volcano, which adversely affects crops.

  As countermeasures, Patent Documents 1 to 3 disclose volcanic ash repellent sheets for agricultural products formed of synthetic resin films.

JP 61-190544 A JP-A-62-42839 Japanese Utility Model Publication No. 62-83447

  However, since the volcanic ash repellent sheets for agricultural products described in these Patent Documents 1 to 3 are all formed of a synthetic resin film as described above, the volcanic ash is well collected and applied to the agricultural products. Although it can prevent adhesion well, there is a problem that it does not have the air permeability necessary for the growth of crops.

  Then, this invention solves such a problem, and it aims at obtaining the volcanic ash repellent sheet | seat for agricultural products which has both the collection property and the breathability of volcanic ash.

  The gist of the present invention is as follows.

  (1) For crops having a surface layer, an intermediate layer, and a back layer, wherein the surface layer and the back layer are composed of spun pond nonwoven fabric, and the intermediate layer is composed of melt blown nonwoven fabric Volcanic ash protection sheet.

  (2) The collection efficiency of dust having a particle size of 0.3 μm or more and less than 0.5 μm and the collection of dust having a particle size of 0.5 μm or more and less than 1 μm when the sheet surface wind speed is 0.0961 cm / sec. The volcanic ash repellent sheet for agricultural products according to (1), wherein the collection efficiency is 60% or more.

(3) The volcanic ash repellent sheet for agricultural products according to (1) or (2), wherein the air permeability is 50 to 300 cc / cm ² / s.

  According to the volcanic ash repellent sheet for agricultural products of the present invention, while maintaining the required sheet strength by the spunbond nonwoven fabric of the front surface layer and the back surface layer, these spunbond nonwoven fabrics, particularly the meltblown nonwoven fabric of the intermediate layer, Can be collected effectively to prevent volcanic ash from reaching crops. Moreover, since all of the front surface layer, the intermediate layer, and the back surface layer are formed of a nonwoven fabric, it is possible to ensure the air permeability necessary for agricultural products. Furthermore, since it is formed of a non-woven fabric, air can be held between the constituent fibers of the non-woven fabric, thereby exhibiting a heat retaining effect on the crop, particularly a defrosting effect.

It is a schematic cross section of the principal part of the volcanic ash protection sheet for agricultural products of embodiment of this invention. It is sectional drawing of the principal part which shows typically the fiber form of each layer in the sheet.

  The volcanic ash repellent sheet for agricultural products of the present invention is used by directly covering agricultural land / field / crop, but as shown in FIG. 1, the surface layer 11, the intermediate layer 12 and the back surface are laminated to each other. It has a layer 13, and these layers 11, 12, 13 are all made of nonwoven fabric. It does not interfere with having other nonwoven fabric layers as long as the effects of the present invention are not impaired. However, it does not have a layer composed of a film.

  The front surface layer 11 and the back surface layer 13 are composed of spunbonded nonwoven fabric, and the intermediate layer 12 is composed of meltblown nonwoven fabric. A spunbond nonwoven fabric is made by dissolving and melting molten thermoplastic resin from a nozzle to form a long fiber, forming a web with the long fiber, and thermally bonding the constituent fibers of the web to each other. Non-woven fabric. Melt blown non-woven fabrics are obtained by forming micron-order ultrafine fibers by ejecting molten thermoplastic resin from a die by the action of high-temperature and high-speed air flow, and forming a web by self-adhering these fibers together. It is what

  In any nonwoven fabric, any resin that can be spun can be used as the thermoplastic resin. For example, a polyolefin-based resin can be preferably used. Specifically, polyethylene, polypropylene, a copolymerized polyolefin obtained by copolymerizing a plurality of polyolefin-based resins, and the like can be used.

  As a mode of thermal bonding between the constituent fibers in the spunbonded nonwoven fabric, it is particularly preferable that the thermal bonding is performed by heat embossing. The nonwoven fabric obtained by heat bonding by hot embossing is formed by applying heat and pressure to the concave heat-bonded part, so that mechanical properties such as strength and form stability are improved. It has become. On the other hand, the portion that is not thermally bonded is hardly affected by heat or pressure, and thus has high flexibility. As a result, the volcanic ash repellent sheet for the crops of the present invention is easy to follow the covering object such as the ground and crops while maintaining the mechanical properties and form stability during use. There is an advantage that a gap is unlikely to be generated between the sheet and the covering object such as the ground or agricultural products, and therefore the laying operation can be easily performed.

  The cross-sectional shape of the fibers of the spunbonded nonwoven fabric is not particularly limited, and not only a general round shape but also a flat shape, a trolley type, a hexaloval type, a W type, an H type, etc. Good. Moreover, polygonal shapes, such as a rectangle and a triangle, may be sufficient, and a hollow shape may be sufficient.

  It is preferable that the surface layer 11, the intermediate layer 12, and the back surface layer 13 are laminated and integrated by thermal bonding. Alternatively, the structure may be integrated with an adhesive or the like.

The spunbond nonwoven fabric of the surface layer 11 and the back surface layer 13 is for imparting a required mechanical strength to the volcanic ash repellent sheet for the agricultural product of the present invention. The strength required for volcanic ash repellent sheets for agricultural products is 1 kgf / 5 cm or more, and the volcanic ash repellent sheets for agricultural products need to be laid in a state following the topography, so the required elongation is 30% or more. In order to exhibit such mechanical characteristics, for example, in the case of a nonwoven fabric formed of a polyolefin-based resin, it is preferable that the single yarn fineness of the constituent fibers is in the range of 1 to 10 dtex. More preferably, it is 2-6 dtex. If the single yarn fineness is less than 1 dtex, the spun yarn may not be able to withstand the drawing tension in the spinning process, which may cause yarn breakage and deteriorate operability. On the other hand, when the single yarn fineness exceeds 10 dtex, the cooling property of the spun yarn in the spinning process may be inferior. As a result, since the yarn comes out from the opening device in a state of being in close contact with heat, the quality of the obtained nonwoven fabric may be inferior. And it is suitable for the fabric weight of a nonwoven fabric that it is the range of 6-30 g / m < ² > in total with the nonwoven fabric of the surface layer 11, and the nonwoven fabric of the back surface layer 13. FIG. When the spunbonded nonwoven fabric has such characteristics, the air permeability required for the volcanic ash repellent sheet for agricultural products of the present invention can also be exhibited.

The melt-blown nonwoven fabric of the intermediate layer 12 is for exhibiting the required volcanic ash collection characteristics after imparting the required air permeability to the volcanic ash repellent sheet for agricultural products. In order to exhibit such performance, for example, in the case of a nonwoven fabric formed of a polyolefin-based resin, it is preferable that the single yarn fineness of the constituent fibers is in the range of 0.01 to 1 dtex. And it is suitable that the fabric weight of a nonwoven fabric is the range of 3-20 g / m < ² >.

In such an intermediate layer 12, as shown in FIG. 2, the ultrafine fibers 21 are gathered densely to form a nonwoven fabric. Thereby, as above-mentioned, it can have required air permeability and volcanic ash collection characteristics. In order to satisfy these performances, the air permeability described later in the volcanic ash repellent sheet for the agricultural product of the present invention having the intermediate layer 12 is preferably 50 cc / cm ² / s or more. That is, the volcanic ash repellent sheet for the agricultural products of the present invention has a dust collection efficiency of a particle size of 0.3 μm or more and less than 0.5 μm and a particle size when the sheet surface wind speed is 0.0961 cm / sec. The dust collection efficiency of 0.5 μm or more and less than 1 μm is preferably 60% or more, and the air permeability is preferably 50 to 300 cc / cm ² / s.

  On the other hand, in the front surface layer 11 and the back surface layer 13, as shown in FIG. 2, the nonwoven fabric is formed in a state where fibers 22 having a larger diameter than the intermediate layer 12 are gathered more “sparsely” than the intermediate layer 12.

  In the nonwoven fabric constituting each of the layers 11, 12, and 13, the antioxidant, the ultraviolet absorber, the light stabilizer, the slip agent, the thermal stabilizer, the flame retardant, and the like, as long as the effects of the present invention are not impaired. Additives such as nucleating agents, insecticides, fungicides, herbicides, and fertilizers may be added. The method for adding these additives is not particularly limited.

Various evaluations in the following examples and comparative examples were performed by the following methods.
(1) Fineness [decitex (dtex)]
In the process of manufacturing the nonwoven fabric, 20 fibers were collected from the nonwoven web, and the fiber diameter was measured with an optical microscope. The average value of values obtained by density correction of the measured values was defined as the fineness.

(2) Sheet weight [g / m ² ]
Ten sample pieces having a sample length of 10 cm and a sample width of 5 cm were collected from the standard sample. The mass [g] of each sample piece was weighed, and the average value obtained was converted per unit area to obtain the basis weight.

(3) Sheet thickness [μm]
Ten thicknesses at a load of 10 kPa were measured using a thickness measuring instrument, and the average value was taken as the thickness.

(4) Strength of sheet [kgf / 5cm width] [%]
Three sample pieces having a sample length of 20 cm and a sample width of 5 cm were collected from the standard sample. Each sample piece was held at a grip interval of 100 mm, pulled at a pulling speed of 200 mm / min, and the elongation (%) when it broke was determined. The average value of the obtained values was defined as the strong elongation of the nonwoven fabric. Moreover, the average value of the stress at the time of 5% elongation and the stress at the time of 10% elongation was obtained from the tensile elongation curve obtained at the time of measurement.

(5) Sheet air permeability [cc / cm ² / s]
Measured based on JIS L 1913 Frazier method.

(6) Water permeability of sheet [%]
Based on JIS L 1013 water permeability, it measured about the both surfaces side of the sheet | seat, and made the average value the water permeability of the sheet | seat.

(7) Light transmittance and light shielding ratio [%] of the sheet
A photocell illuminometer (manufactured by Tokyo Optical Machinery Co., Ltd., model number: SPI5) was used, and the distance from the light source to the sample was set to 300 mm. The light transmittance was measured under the condition of illuminance 2000 lux, and the light shielding rate was measured under the condition of illuminance 10000 lux.

(8) Water pressure resistance [cm] of the sheet
Using a water pressure tester (manufactured by Daiei Kagaku Seiki Seisakusho Co., Ltd., model number: WP-5k), the rising speed of the water column height was set to 100 mm / min.

(9) Sheet dust collection efficiency [%]
A dust generation device and a transmission device to which a sample can be attached were prepared. First, the permeation | transmission apparatus which has not attached the sample was installed in the exit of the dust generator, and the number of pre-permeation | transmission dust before measuring using a sample was measured using the particle | grain counter (Met One237B). Next, a 30 cm square sample was attached to the permeation device, the measurement area in the material was 491 cm ² , the sheet surface wind speed (filtration wind speed) was 0.0961 cm / sec, and the number of dust after permeation was measured. Furthermore, the sample was removed from the transmission device, and the number of dust after the sample measurement for calculating the number of dust before transmission was measured.
The dust collection efficiency [%] was obtained by the following equation.
Dust collection efficiency [%] = {(number of dust before transmission−number of dust after transmission) / number of dust before transmission} × 100
Note that the pre-permeation dust count is the remainder after cutting a total of four maximum and minimum values from each of 15 consecutive measurements for 1 minute before and after measurement using the sample. The average value of the measured values of 11 times was used. The number of dust after permeation is the measured value for the remaining 11 measurements, in which the maximum value and the minimum value are cut from each of the 15 consecutive measurements for 1 minute, a total of 4 each in total during the measurement using the sample. The average value of was used.
Particle size classification 0.3 μm or more and less than 0.5 μm, dust classification 0.5 μm or more and less than 1 μm, dust classification 1 μm or more and less than 3 μm, dust classification 3 μm or more and 5 μm Measurement was performed using less than dust and dust having the same category of 5 μm or more.

Example 1
<Preparation of spunbond nonwoven web (back layer)>
Using an extruder-type melt extruder, the raw material polypropylene (melting point: 169 ° C) is melted and melt spun by a spunbond method at a melting temperature of 230 ° C from a spinneret having a circular fiber cross section. Was drawn while being drawn to 3 dtex, and the drawn fibers were collected on a wire mesh to obtain a nonwoven web having a basis weight of about 5 g / m ² .

<Production of meltblown nonwoven web (intermediate layer)>
Using an extruder-type melt extruder, the raw material polypropylene (melting point: 164 ° C) is melted and melt-spun by a melt blown method at a melting temperature of 245 ° C from a spinneret having a circular fiber cross section. Was reduced to 0.3 dtex. The thinned fibers were collected on the nonwoven web produced by the spunbond method described above to obtain a nonwoven web having a basis weight of about 3 g / m ² .

<Preparation of spunbond nonwoven web (surface layer)>
Fibers were collected on the above-mentioned two-layer nonwoven web by the same method as that for producing the nonwoven web of the back layer, and a nonwoven web having a basis weight of about 5 g / m ² was obtained. Then, a nonwoven web having a three-layer structure having a total basis weight of 12.9 g / m ² was obtained.

<Preparation of volcanic ash protection sheet for agricultural products>
Using an embossing apparatus equipped with an embossing roll and a smooth roll, setting the surface temperature of both rolls to 135 ° C. and setting the partial thermocompression bonding rate to 22%, the laminated structure nonwoven web obtained as described above By applying a partial thermocompression treatment, a non-woven fabric was obtained, and a volcanic ash repellent sheet for agricultural products was obtained.

(Example 2)
Compared with Example 1, the nonwoven webs of basis weight of the intermediate layer as about 5 g / m ^2, a basis weight in total to obtain a nonwoven web of three-layer structure of 14.8 g / m ^2. And the other than that was carried out similarly to Example 1, and obtained the volcanic-ash removal sheet for agricultural products.

  Table 1 shows the measurement results of the physical properties of the volcanic ash repellent sheets for the crops of Examples 1 and 2.

(Comparative Example 1)
A polyethylene film (thickness: 20 μm) was used as Comparative Example 1, but the air permeability was not measurable and the air permeability was zero. When laid over, it hindered the growth of crops.

  Table 2 shows the measurement results of air permeability, water permeability, light transmittance, light shielding rate, and water pressure resistance in the volcanic ash repellent sheets for the crops of Examples 1 and 2.

  Table 3 shows the measurement results of dust collection efficiency in the volcanic ash repellent sheets for the agricultural products of Examples 1 and 2.

  As shown in Tables 1 to 3, the volcanic ash repellent sheets for the crops of Examples 1 and 2 have the required mechanical performance, have air permeability, and have sufficient dust collection performance. It can be used well for the purpose of protecting agricultural products from volcanic ash. Moreover, although it has air permeability, it did not have water permeability and sufficient water pressure resistance, so even if there was rainfall after ash fall, there was no fear that the volcanic ash would permeate and adversely affect crops.

Claims (3)

  Volcanic ash repellent for crops, comprising a surface layer, an intermediate layer, and a back layer, wherein the surface layer and the back layer are composed of spun pond nonwoven fabric, and the intermediate layer is composed of melt blown nonwoven fabric Sheet.   When the sheet surface wind speed is 0.0961 cm / sec, the collection efficiency of dust having a particle size of 0.3 μm or more and less than 0.5 μm, and the collection efficiency of dust having a particle size of 0.5 μm or more and less than 1 μm, Are both 60% or more, the volcanic ash repellent sheet for agricultural products according to claim 1. 3. A volcanic ash repellent sheet for agricultural products according to claim 1 or 2, wherein the air permeability is 50 to 300 cc / cm < ² > / s.

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