JP6997601B2 - Net-shaped foam and its manufacturing method and strawberry cultivation method - Google Patents

Description

The present invention relates to a net-like (mesh-like or mesh-like) foam that is laid on soil and is useful for cultivating fragile fruits such as strawberries, a method for producing the same, and a method for cultivating strawberries.

In the cultivation of strawberries, a method of covering the ground with a cover film called a mulch film is known in order to prevent the strawberries from coming into direct contact with the soil. The mulch film used for strawberry cultivation is required to have water transpiration and soil heat storage in order to promote the growth of strawberries.

Specifically, in strawberry cultivation, irrigation and pesticide spraying are performed to promote growth, but when the environment becomes humid, diseases such as Botrytis cinerea occur. This phenomenon is more closely related to humidity than temperature, and when infection begins, it spreads to surrounding strains and fruits and affects yield. Therefore, the mulch film is required to have a water transpiration property for quickly releasing excess water.

In addition, among the conditions necessary for the growth of strawberries, the geothermal temperature has a great influence on the growth of roots, so geothermal control called night temperature control is performed. In the midnight temperature control, the night is divided into the first half and the second half, and the first half (several hours from sunset) is set as the commutation promotion time zone, and the temperature is kept relatively high to promote the commutation of photosynthetic products. After midnight (from the night before to sunrise), when the commutation is almost over, the night temperature is controlled by controlling the temperature to a low temperature to suppress the exhaustion due to breathing. Therefore, the mulch film is required to have a geothermal heat storage property.

However, the mulch film did not have sufficient soil heat storage property and water transpiration property. Therefore, in recent years, a strawberry cultivation net has also been used as a sheet to be laid in place of or on the mulch film.

For example, in Japanese Patent Application Laid-Open No. 2005-6560 (Patent Document 1), a plurality of foamed strands are arranged in parallel at predetermined intervals to form a strand group, and the plurality of strands are arranged in a state where the foamed strands intersect. In a mesh-like foam net in which the foamed strands are fused and integrated at the intersections thereof, the foamed strands (upper foamed strands) of the strands located at the upper part in the stacking direction among the plurality of strands are foamed. Foaming in which the foaming ratio of the foamed strands (lower foamed strands) of the strand group located at the lower part is reduced to 2 to 25 times (for example, 5 to 20 times) than the magnification of 8 to 40 times (for example, 10 to 30 times). The net is listed. In this document, the cross-sectional shape of the upper foamed strand is almost circular, the cross-sectional shape of the lower foamed strand is flat, and the width of the lower foamed strand is 0.3 to 1.5 times the width of the upper foamed strand. (Especially the same magnification), and it is described that the thickness of the lower foamed strand is 0.1 to 1 times (for example, 0.2 to 0.6 times) the thickness of the upper foamed strand.

However, in such a foamed net, since the cross-sectional shape of the upper foamed strand is circular, sprayed water or chemicals can easily flow down without stopping at the strand, but the strawberries are easily in spot contact and the fruit is easily damaged. At the same time, it cannot support strawberries in a stable manner. Moreover, the diamond-shaped net portion formed by the upper foamed strands surrounds the strawberries, which reduces the air permeability and may cause poor growth or putrefaction of the strawberries. Further, at the contact portion with the upper foamed strand, the ripening or coloring of the strawberry is hindered, and the strawberry may be a strawberry containing an unripened portion (or a white portion). Then, even if the fruit including the unripened portion (or the fruit having a poor color) is originally matured, it may be determined as a defective product by an automatic sorting machine using an optical sensor or the like.

Further, since the cross-sectional shape of the upper foamed strand is circular, it is difficult to increase the fusion strength between the upper foamed strand and the lower strand at the intersection. Further, it is necessary to adjust the expansion ratio of the upper strand and the lower strand, the lower strand having a smaller expansion ratio than the upper strand has high strength and rigidity, and the upper foam strand has a circular cross section. Therefore, in the winding operation, not only the foam net needs to be wound against the repulsive force of the upper strand and the lower strand, but also it is difficult to wind it tightly, so that the storage space and the transportation space are large. Become.

JP-A-2005-6560 (Claims, paragraphs [0022], [0023], [0027], FIG. 2)

Therefore, an object of the present invention is a net-like foam capable of preventing damage to fruits such as strawberries without stopping liquids such as sprayed water and chemicals, and promoting growth while stably supporting the fruits, and production thereof. The purpose is to provide a method as well as a method for cultivating strawberries.

Another object of the present invention is a net-like foam that can increase the fusion strength at the intersection, can be easily wound, and can reduce the storage space and the transportation space, and a method for producing the same, and strawberry. The purpose is to provide a cultivation method.

Still another object of the present invention is a net-like foam which can improve air permeability, water transpiration and soil heat storage, and is useful for promoting the growth and ripening of fruits such as strawberries, a method for producing the same, and strawberries. The purpose is to provide a cultivation method.

As a result of diligent studies to achieve the above object, the present inventor has formed a strand row with a plurality of linear foams, and in a state where the plurality of strand rows are crossed and overlapped with each other, the linear foams are cross-sectioned. In the net-like foam fused in, the cross-sectional shape of the linear foam is flattened, and the cross-sectional shape of the top-level linear foam is the upper surface (contact surface or fruit that can be contacted with the fruit). If the receiving surface) is gently curved, not only liquids such as spraying water and chemicals will flow down along the curved surface, but also fragile fruits such as strawberries will be stable. It was found that the fruit can be effectively protected and the growth can be promoted while supporting the fruit, the linear foam can be brought into surface contact at the cross section to improve the fusion strength, and the winding can be performed extremely easily. Was completed.

That is, the net-like foam of the present invention includes a strand row formed of a plurality of linear foams arranged in parallel with each other at predetermined intervals, and the plurality of strand rows intersect each other. The linear foams that are overlapped and adjacent to each other in the stacking direction are joined or fused at the intersection. In such a net-like foam, the cross-sectional shape of the linear foam is formed into a flat shape. Further, the upper surface of the linear foam of the strand row located at least at the uppermost portion is curved downward toward the linear foams on both sides adjacent to each other.

In each of the strand rows, the expansion ratio M of the linear foam may be, for example, about 5 to 100 times. Further, the expansion ratios of the linear foams of the plurality of strand rows may be different from each other depending on the strand rows, or may be approximately the same. For example, the expansion ratio M1 of the linear foam of the strand row located at the uppermost portion (for example, the first linear foam) and the linear foam of the strand row located at the lower end (for example, the second linear foam). The ratio M1 / M2 of the foam) to the foaming ratio M2 may be, for example, about 0.7 to 1.3, or substantially 1 (substantially the same foaming ratio).

The cross-sectional shape of the linear foam is flat as described above, and when the width of the cross section of the linear foam is W and the thickness is T, the linear foam of the strand row located at the uppermost portion (for example). , The aspect ratio (W / T) of the first linear foam) may be, for example, about 2 to 5. Further, the aspect ratio (W / T) of the linear foam of the lower strand row adjacent to the uppermost strand row (for example, the second linear foam) is the line of the strand row located at the uppermost portion. It may be substantially the same as the aspect ratio of the shaped foam (for example, the first linear foam), or may be as small as about 1.5 to 5.

Further, on the upper surface of the linear foam of the strand row located at the uppermost portion (the receiving surface or the contact surface of the first linear foam), a plurality of concave portions and / or convex portions are spaced apart from each other in the longitudinal direction. May be formed.

More specifically, the net-like foams are arranged in parallel with each other at predetermined intervals and have a plurality of first lines having a contact surface (or a receiving surface capable of receiving fruits) that can contact the strawberries. The first strand row formed of the shaped foam and the first strand row are arranged in parallel with each other at a predetermined interval, and intersect the first linear foam of the first strand row in an oblique direction. It may have a mesh-like (or mesh-like) morphology with a second strand row formed of a plurality of second linear foams joined together.

The cross-sectional shape of the first linear foam and the second linear foam may be narrow and flat, respectively, and the contact surface (or receiving surface) of the first linear foam is , It may be gently curved in the direction of the second linear foam as it goes toward both sides of the adjacent first linear foam. Further, the contact surface (or receiving surface) may have a plurality of recesses (or recesses) at intervals in the longitudinal direction.

The foaming ratio M of the first and second linear foams may be about 10 to 50 times, respectively, and the foaming ratio M1 of the first linear foam and the foaming of the second linear foam The ratio M1 / M2 to the magnification M2 may be about 0.8 to 1.3, and the foaming magnification M1 of the first linear foam and the foaming magnification M2 of the second linear foam are substantially the same. May be. Further, when the width of the cross section of the linear foam is W and the thickness is T, the ratio W1 / W2 of the width W1 of the first linear foam and the width W2 of the second linear foam is, for example, , 1.5 to 3, and the aspect ratio (W / T) of the first linear foam may be, for example, about 2.2 to 4.

Further, the linear foams (for example, the first linear foam and the second linear foam) adjacent to each other in the stacking direction may be surface-contacted at the intersection and fused and joined. , The bonding strength with the linear foam (for example, the first linear foam and the second linear foam) at the intersection is a universal testing machine [AGS-X series (manufactured by Shimadzu Corporation). )], When measured by JIS K6767-1999, for example, it may be about 10 to 100 N / cm ² .

Since the rod-shaped foam has a flat shape, the net-shaped foam can be wound in any direction, and in a form in which a pair of linear foams spread symmetrically from the intersection, the opposing intersections. It may be possible to wind up in the direction connecting the intersections of.

The present invention also includes the method for producing the net-like foam. In this method, the linear foam extruded from each ring die is extruded while extruding the molten foamable resin composition from the bases formed on a plurality of ring dies that are adjacent to each other in the radial direction and can rotate in opposite directions. The net-like foam is produced by fusing at the intersection. In this method, the outermost ring dies (for example, the first ring dies) are formed at intervals in the circumferential direction, and the height of the outer peripheral wall is large on both sides (the length in the radial direction is large). A mouthpiece that is small (small radial length) in the middle of the circumference (for example, a mouthpiece with an inwardly curved outer peripheral wall) and an inner ring die that is adjacent to the outermost ring die (for example). , The net-like foam can be produced by extruding the molten foamable resin composition from the base portions having a predetermined length formed at intervals in the circumferential direction of the second ring die).

The net-like foam of the present invention can be used for cultivating various fruits. For example, the net-like foam may be laid on the soil to cultivate strawberries.

In the present specification, the foaming magnification M, the average width W, and the average thickness T of the linear foam are separated from each other between the intersections (for example, intersecting the intersections). (Linear foam in the middle part between the parts) is randomly sampled, and means the average value of 10 sample samples.

In the present invention, since the uppermost linear foam has a predetermined flat morphology, a liquid such as spray water or a chemical solution can flow down along the outer periphery of the linear foam, and strawberry. It is easy to make surface contact with fruits such as strawberries, it is possible to prevent damage to fruits such as strawberries, and it is possible to effectively protect fragile fruits. In addition, since a plurality of strand rows are superposed to form a net, the air permeability is high, and the growth can be promoted while stably supporting the fruit.

Further, since a predetermined flat linear foam is joined at the intersection, the fusion strength at the intersection can be increased, and the foam can be easily wound up, reducing the storage space and the transportation space. can. Furthermore, it is possible to improve air permeability, water transpiration and soil heat storage, and promote the growth and ripening of fruits such as strawberries. In particular, when the uneven portions are formed at intervals in the longitudinal direction of the uppermost linear foam, the air permeability can be improved, the light reflection efficiency can be improved, and the coloring and ripening of the fruit can be promoted.

FIG. 1 is a schematic perspective view showing an example of the net-like foam of the present invention. FIG. 2 is a schematic enlarged view showing a part of the net-like foam of FIG. 1. FIG. 3 is a schematic cross-sectional view showing an intersection where the first linear foam and the second linear foam partially intersect in the net-like foam of FIG. 1. FIG. 4 is a schematic cross-sectional view showing a partial intersection of another net-like foam of the present invention. FIG. 5 is a schematic view for explaining the method for producing the net-like foam of the present invention. FIG. 6 is a graph showing the results of winding tests of Examples and Comparative Examples. FIG. 7 is a graph showing the results of the geothermal heat storage property of Examples and Comparative Examples.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings as necessary.

The net-like foam (or mesh-like fruit protective material or cushioning material) 1 shown in FIGS. 1 to 3 is located at the uppermost portion and is a first strand row formed of a plurality of first linear foams 3. 2. And a plurality of second lines located below the first strand row and fused diagonally with respect to the first linear foam 3 of the first strand row 2. A second strand row 4 formed of the shaped foam 5 is provided, and in the first strand row 2 and the second strand row 4, the plurality of first linear foams 3 and the plurality of second strands 3 are provided. The linear foams 5 of the above are arranged in parallel with each other at predetermined intervals (for example, at intervals of 10 to 15 mm in this example). Therefore, the net-shaped foam 1 has a mesh-like morphology having a diamond-shaped (or diamond-shaped frame-shaped) mesh structure. That is, a pair of linear foams 3 and 5 spread symmetrically from the intersection and are formed in a rhombic shape (or a rhombic frame shape).

Further, the first linear foam 3 and the second linear foam 5 are each made of an ethylene resin foam having a closed cell structure having a foaming ratio of about 10 to 40 times. Further, the uppermost first linear foam 3 and the lower second linear foam 5 are formed at substantially the same foaming ratio, and the foam of the uppermost first linear foam 3 is formed. The ratio M1 / M2 between the magnification M1 and the expansion magnification M2 of the lower second linear foam 5 is about 0.9 to 1.3. Even if the foaming ratio of the second linear foam 5 is equal to the foaming ratio of the first linear foam 3, the plurality of first linear foams 3 and the second line are as described below. Since the shaped foam 5 has a flat cross section, it can be joined with high joining strength at the intersection.

The plurality of first linear foams 3 and the second linear foams 5 are each formed to have a narrow width, and as described above, the cross-sectional shape is formed to be flat. In this example, when the width of the cross section of the linear foam is W and the thickness is T, the aspect ratio (W1 / T1) of the first linear foam 3 is formed to be about 2.2 to 3.5. The aspect ratio (W2 / T2) of the second linear foam 5 is formed to be about 1.7 to 3. Further, the width W1 of the first linear foam 3 is formed larger than the width W2 of the second linear foam 5 (W1> W2), for example, the width W1 of the first linear foam 3. = 5 to 10 mm, width W2 of the second linear foam 5 = about 2 to 5 mm, width ratio W1 / W2 = about 1.7 to 2.2. The width of the intersection is formed to be larger than the width W1 of the first linear foam 3, and at the intersection, the width W1 of the first linear foam 3 located in the middle between the adjacent intersections. It may have a form that gradually swells in the width direction. Further, the thickness T1 of the first linear foam 3 is formed to be larger than the thickness T2 of the second linear foam 5 (T1> T2), for example, the thickness T1 of the first linear foam 3. = 1.5 to 3.5 mm, the thickness of the second linear foam 5 is about T2 = 0.7 to 2.5 mm, and the thickness ratio is T1 / T2 = about 0.5 to 0.9. ..

Since it has such a flat shape, the first linear foam 3 and the second linear foam 5 can be welded in close contact with each other on a large surface at the intersection, and can be welded. The fusion strength at the part can be improved.

Further, the upper surface of the first linear foam 3 located at the uppermost portion has a contact surface (or a receiving surface that can receive the strawberry) that can come into contact with the strawberry, and this contact surface (or the receiving surface). Is curved and descends in the width direction of the first linear foam 3. That is, the contact surface (or receiving surface) is directed toward the first linear foam 3 on both adjacent sides (or toward both sides of the width of the first linear foam 3). It is gently curved downward (or toward the second linear foam 5). Further, the lower surface of the first linear foam 3 may be flat, or may be gently curved toward the second linear foam 5 in a convex or concave shape.

Further, the upper surface (contact surface or receiving surface) of the first linear foam 3 is spaced in the longitudinal direction and has a predetermined length in the longitudinal direction (for example, the first linear foam 3 and / /. Alternatively, it has a plurality of recessed portions (or curved recessed portions) 3a that are curved and extended with a length (about the same length as the width of the second linear foam 5), and forms an uneven surface. That is, the upper surface (contact surface or receiving surface) of the first linear foam 3 may have a wavy shape (or a wavy shape) in the longitudinal direction. The upper surface and the lower surface of the second linear foam 5 may be flat, or may be gently curved toward the first linear foam 3 in a convex or concave shape.

Fine uneven portions are formed on the peripheral surfaces of the first linear foam 3 and the second linear foam 5.

When such a net-like foam 1 is laid on the ridge and cultivated as a strawberry, the first linear foam 3 of the first strand row 2 at the top has a flat shape, so that the strawberry Can be stably supported on the upper surface (contact surface or receiving surface) of the first linear foam 3, effectively protect fragile strawberries, and prevent scratches. In particular, since the upper surface of the first linear foam 3 has a plurality of recesses 3a at intervals in the longitudinal direction, the first linear foam 3 and the strawberry can be stably supported while the strawberry is stably supported. A space or a gap can be secured between them, and high air permeability can be ensured. Therefore, the growth can be promoted, the light reflection efficiency can be improved, and the coloring and aging of strawberries can be promoted. Further, even if a liquid such as water or a chemical solution is sprayed or dew condensation water is dropped, the upper surface of the first linear foam 3 is curved, so that the liquid flows down along the curved surface to drain water. It can be improved and the strawberry spoilage can be prevented. Further, since the first linear foam 3 and the second linear foam 5 are joined (or fused) in a flat form at the intersection, the linear foams 3 and 5 are bonded at the intersection. Not only can it be brought into surface contact to improve the fusion strength, but it can also be wound tightly and easily in the direction connecting the opposing intersections on the narrow angle side of the intersection, so that it can be wound extremely easily. Therefore, the net-like foam 1 can be wound up with a small volume, and the storage space and the transportation space of the wound net-like foam 1 can be reduced. In addition, since the adhesive strength between the strand rows is also improved, damage (particularly tearing) of the net-like foam during winding work can be improved.

The net-like foam may be formed of a plurality of strand rows, and may be formed of not only two strand rows but also three or more strand rows. The strand row can be formed of a plurality of linear foams arranged in parallel with each other at predetermined intervals, and the spacing between the plurality of linear foams is the type and size of the fruit (eg, strawberry). Depending on the situation, it may be, for example, 5 to 30 mm (for example, 7 to 25 mm), preferably about 10 to 25 mm (for example, 12 to 20 mm), and may be about 10 to 20 mm (for example, 12 to 15 mm). You may. In the net-like foam having three or more strand rows, the upper and lower strand rows (first strands) adjacent to each other via the intermediate strand row (second strand row) in the stacking (or thickness) direction. The positions of the rows and the third strand rows) may overlap in the width direction or may differ from each other.

The plurality of strand rows are superposed so as to intersect each other, and the linear foams adjacent to each other in the superposition direction are joined (or fused) to each other at the intersection.

The plurality of strand rows (linear foams) may intersect in a direction orthogonal to each other, or may intersect in an oblique direction. The crossing angle of the plurality of strand rows (linear foams) (the crossing angle on the narrow angle side of the crossing portion between the first linear foam and the second linear foam) is not particularly limited. For example, it may be about 10 to 90 ° (for example, 15 to 80 °), usually 10 to 45 ° (for example, 15 to 40 °), preferably 15 to 30 ° (for example, 15 to 25 °). It may be about.

The cross-sectional shape of the linear foam forming each strand row may be a flat shape, may be wide, or may be narrow. The cross-sectional shape of the linear foam is usually narrow and flat in many cases.

In each strand row, the linear foam may have substantially the same width in the longitudinal direction, and at the intersection, the linear foam may be welded in a form in which the width is narrowed or increased. As described above, in many cases, the linear foam is welded in a form in which the width is widened. Further, in each strand row, the thickness of the linear foam may be substantially the same in the longitudinal direction, may be larger or smaller at the intersection, and may be intermediate located between adjacent intersections. The portion (free portion) may be smaller or larger.

Specifically, when the average width of the cross section of the linear foam is W and the average thickness is T, the linear foam of the highest strand row located on the fruit side (the highest linear foam, for example, The average width W1 of the first linear foam 3) of the first strand row 2 is, for example, 1 to 30 mm (for example, 2 to 20 mm), preferably 3 to 15 mm (for example, 4 to 12 mm), and further. It may be preferably about 5 to 10 mm (for example, 5 to 8 mm). If the average width W1 is too small, the strength of the net-like foam is reduced and the support stability for the fruit is lowered, and if it is too large, the weight of the net-like foam is increased, and drainage, breathability and winding are reduced. The pickability may decrease.

The average thickness T1 of the top-level linear foam is, for example, 0.5 to 15 mm (for example, 1 to 12 mm), preferably 1.5 to 10 mm (for example, 1.7 to 8 mm), and more preferably 2 to 2. It may be about 5 mm). If the average thickness T1 is too small, the strength of the net-like foam is lowered and the drainage property is lowered, and if it is too large, the weight of the net-like foam is increased and the take-up property may be lowered.

The average aspect ratio R1 (W1 / T1) of the uppermost linear foam is, for example, 2 to 5 (for example, 2.2 to 4), preferably 2.5 to 3.5 (for example, 2.7 to). 3.3) It may be about. If the average aspect ratio R1 is too small, the support stability for the fruit is lowered, and if it is too large, the weight is increased and the drainage property may be lowered.

A linear foam of a lower strand row adjacent to the uppermost strand row and located on the soil side (for example, a lower linear foam, for example, a second linear foam 5 of the second strand row 4). The average width W2 may be the same as the average width W1 of the top-level linear foam, and may be larger or smaller than the average width W1 of the top-level linear foam. In order to improve the drainage and take-up properties of the net-like foam, the average width W2 of the lower linear foam is often smaller than the average width W1 of the uppermost linear foam (W1> W2). ). The average width W2 of the lower linear foam is, for example, 0.5 to 25 mm (for example, 1 to 20 mm), preferably 2 to 15 mm (for example, 3 to 10 mm), and more preferably 2 to 8 mm (for example, 2). It may be about .5 to 7 mm) or about 2 to 6 mm (for example, 2.5 to 5 mm). If the average width W2 is too small, the strength of the net-like foam is reduced and the support stability for the fruit is lowered, and if it is too large, the weight of the net-like foam is increased, and drainage, breathability and winding are reduced. The pickability may decrease.

The ratio W1 / W2 of the average width W1 of the upper linear foam and the average width W2 of the lower linear foam can be selected from, for example, about 0.5 to 1.5, and is usually 1 to 3. (For example, 1.2 to 3), preferably about 1.5 to 2.5 (for example, 1.7 to 2.3) may be used.

The average thickness T2 of the lower linear foam may be the same as the average thickness T1 of the uppermost linear foam, or may be larger or smaller than the average thickness T1 of the uppermost linear foam. You may. In order to improve the drainage and take-up properties of the net-like foam, the average thickness T2 of the lower linear foam is equal to or smaller than the average thickness T1 of the uppermost linear foam. (T1 ≧ T2). The average thickness T2 of the lower linear foam is, for example, 0.3 to 15 mm (for example, 0.5 to 12 mm), preferably 0.7 to 10 mm (for example, 1 to 5 mm), and more preferably 1.2. It may be about 2.5 mm (for example, 1.5 to 2 mm). For example, the ratio T1 / T2 of the average thickness T1 of the upper linear foam and the average thickness T2 of the lower linear foam can be selected from, for example, about 0.5 to 1.5, and is usually 0. It may be about .5-1 (for example, 0.5 to 0.9), preferably about 0.6 to 0.8 (for example, 0.7 to 0.8). If the average thickness T2 is too small, the strength of the net-like foam is lowered and the drainage property is lowered, and if it is too large, the weight of the net-like foam is increased and the take-up property may be lowered.

The average aspect ratio R2 (W2 / T2) of the lower linear foam is, for example, 1.5 to 5 (for example, 1.6 to 4), preferably 1.7 to 3.5 (for example, 1.75). It may be about 3) or about 1.5 to 2.5 (for example, 1.7 to 2.3). The average aspect ratio R2 of the lower linear foam may be the same as the average aspect ratio R1 of the uppermost linear foam, and is usually smaller than the average aspect ratio R1. Therefore, the ratio of the average aspect ratio (R1 / R2) may be about 0.5 to 3, but is usually 0.8 to 2.5 (for example, 1 to 2.5), preferably 1. It may be about 2 to 2.2 (for example, 1.3 to 1.7) or about 1.1 to 2 (for example, 1.25 to 1.75).

Further, the upper surface of the linear foam of the strand row located at least at the uppermost portion (for example, the first linear foam 3 of the first strand row 2) is adjacent to the linear foams on both sides (for example). , The direction toward the first linear foam 3) (or the width direction) is curved downward (for example, the direction toward the second linear foam 5). The shape of the upper surface may be a mountain shape, and is usually a semicircular shape, particularly a semicircular shape that curves gently. Further, the shape of the upper surface is often a shape in which the top is gently inclined or curved, and the top is relatively largely curved on both sides. Since the linear foam of the strand row at the uppermost position has the above-mentioned morphology, even if a chemical solution, water, etc. is sprayed or dew condensation water drips in house cultivation, the liquid smoothly flows down toward the soil. It can be made to drain, the drainage can be improved, and the disease and rot of fruits can be prevented.

The lower surface of the linear foam of the uppermost strand row may be curved downward (for example, gently curved), and is usually flat or curved upward (for example, gently curved). You may. The lower surface of the linear foam is often curved upward (for example, gently curved) corresponding to the upper surface.

Further, the upper surface and the lower surface of the linear foam of the lower strand row adjacent to the uppermost strand row (for example, the second linear foam 5) are the uppermost linear foam (for example, the said). It may have the same form as the first linear foam 3), and the upper surface may be flat or may be curved downward (for example, gently curved).

FIG. 4 is a schematic cross-sectional view showing a partial intersection of another net-like foam of the present invention. In this example, the cross-sectional shape of the linear foam (first linear foam 13) of the uppermost strand row has a top surface that is gently inclined or curved at the top and relatively largely curved at both sides. It has a contact surface with fruits) and a curved lower surface that gently rises upward corresponding to the upper surface. Further, the cross-sectional shape of the linear foam (second linear foam 15) of the lower strand row has an upper surface that is gently descended downward and curved, and a lower surface that is curved corresponding to the upper surface. The height position of the upper surface of the second linear foam 15 is lower than the upper surface of the first linear foam 13.

Even if the net-like foams are formed of the linear foams 13 and 15 having such a shape, the fruit can be stably supported on the curved upper surface of the first linear foam 13 and the fruit can be stably supported on the curved upper surface of the first linear foam 13, as described above. Fruits can be grown while ensuring air permeability in the mesh-like space and the height space formed by the first linear foam 13 and the lower second linear foam 15. Further, even if the upper surface of the second linear foam 15 is gently curved downward, breathability is provided in the height space between the first linear foam 13 and the second linear foam 15. It can be secured, it can provide an appropriate humidity environment, and it can prevent fruit rot and diseases.

Further, the upper surface (contact surface or receiving surface) of the linear foam of the strand row located at the uppermost portion (for example, the first linear foams 3, 13) is uniform in the longitudinal direction (relative to the thickness direction). It may be flat), but it is long in order to suppress excessive contact with the fruit (for example, surface contact) and to form a gap with the fruit to improve air permeability, light reflectivity, etc. It is preferable to have a plurality of concave portions and / or convex portions at intervals in the direction. The uneven portion is not limited to the recessed portion (the recessed portion curved downward in a predetermined length range) as described above, but may be formed by a convex portion (curved concave portion or valley portion), or the convex portion (convex portion). It may be formed by a curved convex portion or a mountain portion). Further, the uneven surface on which the plurality of concave portions and / or convex portions are formed is regularly or irregularly wavy in the longitudinal direction (or) due to the uneven portions formed at intervals in the longitudinal direction. It may have a wavy form). Since the upper surface of such a linear foam is curved in the circumferential direction and has recesses and / or protrusions in the longitudinal direction, it provides support stability, breathability and light reflectivity to fruits. It can be improved and promote fruit growth, coloring and ripening.

The concave portion and / or the convex portion such as the recessed portion is formed at an appropriate position in the longitudinal direction on the upper surface (receiving surface or contact surface) of the linear foam (for example, the first linear foams 3, 13). It can be formed, for example, at or near the intersection with the lower linear foam (for example, the second linear foams 5, 15), or at an intermediate portion located in the middle of the adjacent intersection. You may.

The linear foam can be formed of a foamable thermoplastic resin composition. Examples of the thermoplastic resin include olefin resins, styrene resins, vinyl chloride resins, vinyl acetate resins, polyvinyl alcohol resins, acrylic resins, polyacetal resins, polyester resins, polycarbonate resins, and polyamide resins. Examples include thermoplastic elastomers. These resins may be used alone or in combination of two or more. Among these resins, olefin resins (eg, ethylene resins, propylene resins, etc.), styrene resins (eg, polystyrene, etc.), thermoplastic elastomers (eg, olefin thermoplastic elastomers, styrene thermoplastic elastomers, etc.), etc. ) Is preferable, and at least an olefin-based resin (particularly, an ethylene-based resin) is preferable because it is excellent in mechanical properties such as flexibility and elasticity.

Examples of the olefin resin include polyethylene (polyethylene such as high-density polyethylene, low-density polyethylene, and linear low-density polyethylene), polypropylene, and α-C _2-4 chain olefins such as ethylene-propylene copolymer alone or by weight. Examples thereof include a coalescence, a polyethylene-vinyl acetate copolymer (EVA resin) and the like. These olefin resins can also be used alone or in combination of two or more. As the olefin-based resin, polyethylene-based resins such as high-density polyethylene, low-density polyethylene, and linear low-density polyethylene are generally used. The polyethylene-based resin also includes a metallocene polyethylene-based resin prepared by using a metallocene catalyst.

The thermoplastic resin composition contains a conventional foaming agent as a foaming component, and the foaming agent may be a degradable foaming agent (chemical foaming agent), but from the viewpoint of corrosiveness, handleability, and the like, the foaming agent may be a degradable foaming agent. A volatile foaming agent (physical foaming agent) may be used. Examples of the volatile foaming agent include an inorganic foaming agent (nitrogen, carbon dioxide, oxygen, air, water, etc.) and an organic foaming agent (aliphatic hydrocarbon, alicyclic hydrocarbon, aromatic hydrocarbon, chloride hydrocarbon). Hydrogen, fluorinated hydrocarbons, alcohols, ethers, aldehydes, ketones, etc.) and the like. Of these, lower aliphatic hydrocarbons such as butane (n-butane, isobutane) and pentane (n-pentane, isopentane, etc.) are widely used because they are inexpensive and have low toxicity.

The ratio of the foaming agent is, for example, 0.01 to 30 parts by weight, preferably 0.1 to 25 parts by weight, and more preferably 1 to 20 parts by weight (particularly 5 to 15 parts by weight) with respect to 100 parts by weight of the resin. Part)

The foamed resin composition may contain a bubble adjusting agent. Examples of the bubble adjusting agent include silicon compounds (talc, silica, zeolite, etc.), inorganic acid salts (carbonates such as sodium carbonate, sodium hydrogencarbonate, etc.), organic acids or salts thereof (citrate, citrate, etc.). Examples thereof include sodium acid, calcium stearate, aluminum stearate, zinc stearate, etc.), metal oxides (zinc oxide, titanium oxide, aluminum oxide, etc.), and metal hydroxides (aluminum hydroxide, etc.). These bubble regulators may be used alone or in combination of two or more.

The ratio of the bubble adjusting agent is, for example, 0.01 to 10 parts by weight, preferably 0.05 to 5 parts by weight, and more preferably 0.1 to 3 parts by weight (particularly 0.5) with respect to 100 parts by weight of the resin. ~ 2 parts by weight).

The foamed resin composition may contain a shrinkage inhibitor. Examples of the shrinkage inhibitor include fatty acid esters (esters of _C8-24 fatty acids such as palmitic acid mono-triglyceride, stearic acid mono-triglyceride and polyhydric alcohols), fatty acid amides (palmitic acid amides, stearic acid amides, etc.). C _8-24 fatty acid amide, etc.) and the like. These shrinkage inhibitors may function as surfactants for improving water transpiration. These shrinkage inhibitors can be used alone or in combination of two or more.

The ratio of the shrinkage inhibitor is, for example, 0.01 to 30 parts by weight, preferably 0.05 to 20 parts by weight, and more preferably 0.1 to 10 parts by weight (particularly 1 to 5) with respect to 100 parts by weight of the resin. (Weight part).

Foamed resin compositions include conventional additives such as colorants (dye, pigment, etc.), surface smoothers, stabilizers (antioxidants, heat stabilizers, UV absorbers, etc.), viscosity modifiers, and compatibility. Agents, dispersants, antistatic agents, antiblocking agents, antifogging agents, fillers (calcium carbonate, carbon fibers, etc.), lubricants, mold release agents, lubricants, impact improvers, plasticizers, flame retardants, biosides ( It may contain a bactericidal agent, a bacteriostatic agent, an antifungal agent, a preservative, an insect repellent, etc.), a deodorant and the like. These additives can be used alone or in combination of two or more.

The colorant may be a chromatic colorant or an achromatic colorant. In the present invention, by using a colorant, the absorption and reflectivity of light can be adjusted, and the growth, coloring and ripening of fruits can be adjusted. For example, a black colorant (for example, carbon black) can be used to improve light absorption and heat storage at soil temperature, and a white colorant (titanium oxide, calcium carbonate, etc.) can be used to improve light reflectivity. can. Therefore, achromatic colorants (black colorants and / or white colorants) are often used.

The expansion ratio M of the linear foam in each strand row of the effervescent resin composition is not particularly limited as long as it has a buffering property, and is, for example, 5 to 100 times (for example, 10 to 50 times), preferably 5 to 5. It may be about 30 times (for example, 10 to 25 times), more preferably about 15 to 25 times. If the foaming ratio is too low, the impact absorption may be lowered, and if it is too high, the mechanical strength and flexibility may be lowered.

The foaming ratio of the linear foam in each strand row may be the same or different, but in the present invention, it is not necessary to adjust the foaming ratio of the linear foam in each strand row. For example, the expansion ratio M1 of the linear foam of the strand row located at the uppermost portion (first linear foams 3, 13) and the linear foam of the strand row located at the lower end (second linear foam). The ratio M1 / M2 to the foaming ratio M2 of 5,15) is, for example, 0.7 to 1.3 (for example, 0.8 to 1.3), preferably 0.8 to 1.2, and more preferably 0.7 to 1.2. It may be about 0.9 to 1.1, and the foaming ratio of each linear foam may be substantially the same.

The average cell diameter of the linear foam is, for example, 0.2 to 2 mm, preferably 0.4 to 1.8 mm, more preferably 0.5 to 1.5 mm (particularly 0.3 to 1.2 mm). be. If the average cell diameter is too small, the cushioning property may decrease, and if it is too large, the mechanical properties deteriorate.

The foaming structure of the linear foam may be an open cell structure, but a structure containing at least closed cells is preferable, and a closed cell structure (closed cell structure) is particularly preferable. The ratio of closed cells to the total bubbles (total of open cells and closed cells) is, for example, 85 to 100%, preferably 90 to 100% (for example, 90 to 99%), and more preferably 93 to 100% (for example). , 93-99%).

At the intersection, flat linear foams are surface-contacted and bonded or fused. Therefore, the bonding strength of the linear foam at the intersection is high. The bonding strength depends on the type of the thermoplastic resin, the foaming ratio, etc., but when the thermoplastic resin is an olefin resin (particularly an ethylene resin) and the foaming ratio is about 10 to 40 times, for example, It may be about 10 to 100 N / cm ² (for example, 20 to 95 N / cm ² ), preferably about 30 to 90 N / cm ² , and more preferably about 40 to 80 N / cm ² . The joint strength of the linear foam adjacent to the superposition direction (thickness direction) is obtained by measuring the tensile or peel strength according to JIS K6767: 1999 and dividing by the cross-sectional area (cm ² ) of the joint. Can be calculated.

As described above, the net-like foam of the present invention can be wound from various directions because the flat linear foam is joined in a net-like form. In particular, in a form in which a pair of linear foams extend symmetrically from the intersection (expanded form), the net-like foams are formed at the opposite intersections on the narrow angle side of the intersection (particularly on the narrow angle side). It is possible to wind up in the direction connecting the opposite intersections. Therefore, the wound net-like foam can be easily spread on the soil (or medium) such as ridges, and the layability can be improved.

In particular, since the cross-sectional shape of the linear foam is flat and can be wound (or wound) tightly, the volume of the wound net-shaped foam can be reduced, and the storage space and transportation space can be reduced. can. For example, the cross-sectional shape is flat as compared with the net-shaped foam using the first linear foam having a circular cross-sectional shape and the second linear foam having a horizontally oblong elliptical cross-sectional shape. In the net-like foam using the first and second linear foams, not only the ease of winding can be greatly improved, but also the winding diameter can be increased by at least 5% or more, for example, 7 to 25% (for example, 7 to 25%). For example, it can be reduced by 10 to 25%). Moreover, since the linear foam can be fused by surface contact over a large area and the linear foam is bonded with high adhesive strength, it has high mechanical strength while having high cushioning properties, and it can be laid. It can be used repeatedly by winding and has high durability. Therefore, the net-like foam can be used repeatedly according to the cultivation cycle.

[Manufacturing method of net-like foam]
The net-like foam of the present invention is extruded while crossing the linear foams of each strand row, and the linear foams adjacent to each other in the stacking direction are joined (particularly fused) to each other at the intersection. Can be prepared.

FIG. 5 is a schematic view for explaining the method for producing the net-like foam of the present invention. In the method shown in this figure, the extrusion foam molding machine includes a first ring die 21 and a second ring die 22 that are adjacent to each other in the radial direction and can rotate in opposite directions. On the inner wall in the circumferential direction of the first ring die 21 on the outer peripheral side, a plurality of wide first base portions 23 having an inwardly curved or recessed outer peripheral wall are formed at intervals. A plurality of second base portions 25 having a width narrower than that of the base portion 23 are formed on the outer wall of the second ring die 22 on the peripheral side in the circumferential direction at intervals. The width (or the length in the circumferential direction) and the height (the length in the radial direction) of the first base portion 23 are formed to be larger than those of the second base portion 25.

In such a foam molding machine, the foamable thermoplastic resin composition is melt-kneaded, and while the ring dies 21 and 22 are rotated in the opposite directions, the melted foamable resin composition is transferred to the ring dies 21 and 22. When extruded from the base portions 23 and 25, the linear foams 3 and 5 shown in FIG. 1 form the strand rows 2 and 4 in the circumferential direction of the first base portion 23 and the second base portion 25. When the positions match, the linear foams 3 and 5 intersect and fuse, and a tubular net-like foam in which the strand rows 2 and 4 are stacked can be generated, and the generated tubular net-like foam can be generated. The net-like foam 1 can be manufactured by incising or cutting the body 1 along the extrusion direction.

When a plurality of ring dies are adjacent to each other in the circumferential direction and the molten foamable resin composition is extruded from the base portion of each ring die, a plurality of strand rows are stacked and fused at the intersection. Can be manufactured.

Of the plurality of ring dies, a base portion (for example, a first base portion 23) is formed at intervals in the circumferential direction of the outermost ring die (or the outer peripheral ring die), and the form of the base portion is formed. Alternatively, the shape can be selected according to the morphology of the linear foam to be produced. That is, when the effervescent resin composition is melt-extruded from a base portion having a square cross section, it expands while foaming in the atmosphere to form a linear foam having a substantially circular cross section. Further, when melt extrusion molding is performed from a horizontally long base portion having a rectangular cross section, a linear foam having an elliptical cross section is generated. Therefore, even if melt extrusion molding is performed from a slit-shaped elongated base portion, a linear foam having a flat cross-sectional shape can be produced, but in the net-shaped foam, the intersection of the linear foams can be widened. There is sex. Therefore, it is preferable that the height of the outer peripheral wall of the base portion is large on both side portions and small in the middle portion in the circumferential direction. The shape of the outer peripheral wall of the base portion may be a concavo-convex shape in which the height is gradually changed as long as the height (space height) in the intermediate portion is smaller than that on both sides in the circumferential direction, and is continuous. It may have a curved shape with a variable height. Usually, the shape of the base portion (for example, the first base portion 23) is often a shape in which the heights of both side portions are large, the height of the intermediate portion is small, and the height is curved inward.

The base portion of the inner ring die (inner peripheral ring die, for example, the second base portion 25) adjacent to the outermost ring die is also formed at intervals in the circumferential direction, and the form of this base portion is also a line. It can be selected according to the morphology of the foam. For example, the length of the base portion in the circumferential direction is not particularly limited as long as it can overlap with the first base portion 23 by a predetermined length with rotation, and the base portion of the ring die on the outermost peripheral side (for example, for example). It may be equal to or larger than the length of the first base portion 23), and is usually smaller than the length of the base portion (for example, the first base portion 23), and is often formed in a narrow shape.

The height of the base portion of the outer peripheral ring die (average length in the radial direction) may be equal to the height of the base portion of the inner peripheral ring die, and is larger than the height of the base portion of the inner peripheral ring die. It may be small or small. Normally, the height of the base portion of the outer peripheral ring die is formed to be equal to or smaller than the height of the base portion of the inner peripheral ring die.

Further, in the base portion of the form of the outermost ring die, the ratio of the heights of both side portions and the intermediate portion in the circumferential direction, the supply speed of the molten resin composition to the base portion of the ring die, and the like are adjusted. Therefore, the thickness of the linear foam can be adjusted between the adjacent intersections, and a plurality of concave portions and / or convex portions can be formed in the longitudinal direction of the uppermost linear foam.

By extruding the melt-kneaded foamable resin composition from a ring die (mold) having such a base portion, the linear foam can be fused at the intersection to produce the net-like foam.

The melt kneading and extrusion foaming can be performed by a conventional method. Examples of the extruder include a single-screw extruder (for example, a vent type extruder), a multi-stage extruder (for example, a tandem extruder, etc.), and the like, and a multi-stage extruder (particularly, a two-stage extruder) for adjusting foaming conditions. A shaft type tandem extruder, etc.) may be used.

The method of introducing the foaming agent is not particularly limited, and the foaming agent may be blended in the resin composition in advance, or a foaming component (for example, butane) may be introduced into the extruder. For example, a resin composition is charged into a first extruder on the upstream side of a twin-screw tandem extruder, and a foaming component is injected from the middle of the first extruder to obtain a foamed resin composition on the downstream side. It may be cooled to a suitable foaming temperature with a second extruder and extruded from the mold. The screw diameter of the second extruder is, for example, 1.1 to 1.5 times, preferably 1.2 to 1.4 times, the screw diameter of the first extruder. May be good.

The extruded foamed resin composition may be cooled by injecting a cooling medium (particularly, compressed air) such as compressed air, blower (air), and water in parallel with the cooling step by the sizing die. The temperature of the cooling medium is not particularly limited, and may be, for example, 0 to 60 ° C., preferably about 10 to 50 ° C. In the method of injecting compressed air, the air pressure may be, for example, about 0.1 to 10 MPa, preferably 0.2 to 5 MPa (for example, 0.3 to 1 MPa). The injection amount of compressed air may be, for example, about 100 to 1000 liters / minute, preferably about 200 to 500 liters / minute.

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

Example 1
The resin composition of the following formulation was put into the first extruder (screw diameter 65 mm) of the tandem extruder (manufactured by Plastic Giken Co., Ltd.), and butane gas [i-butane / n- Butane (volume ratio) = 20/80] After injecting 10 parts by weight, adjust the foaming temperature to an appropriate temperature with a second extruder (screw diameter 90 mm), and attach it to the tip of the mold (ring die) shown in FIG. The net-like foam having the form shown in FIG. 1 was obtained by extrusion foaming from the base of the above. The length of the first base portion in the circumferential direction is 4 mm, the height of both sides is h1 = 1.7 mm, and the ratio between the height h1 of both sides and the height h2 of the intermediate portion h1 / h2 = 1.3. Is. The foaming ratio of the obtained foam was 30 times, the average width W1 of the first linear foam was 6.5 mm, the average thickness T1 was 2.4 mm, and the average width W2 of the second linear foam was 3. 3 mm, the average thickness T2 is 2 mm, the distance between the plurality of first linear foams is 140 mm, the distance between the plurality of second linear foams is 150 mm, and the distance between the first linear foam and the second linear foam is 150 mm. The crossing angle with the linear foam was 20 °. In addition, curved recesses were formed on the upper surface of the first foam adjacent to the intersection at intervals in the longitudinal direction.

(Resin composition)
LDPE (manufactured by Sumitomo Chemical Co., Ltd., "F108-R") 70 parts by weight LLDPE (manufactured by Ube Kosan Co., Ltd., "20B") 30 parts by weight Anti-shrinkage agent: Monoglyceride stearate (manufactured by Nippon Beringer Co., Ltd., "ACTIV325") 3.2 parts by weight Foaming nucleating agent: talc with an average particle diameter of 7.4 μm, "Microace K-1" manufactured by Nippon Tarku Co., Ltd. 1.7 parts by weight Black colorant: manufactured by Tokyo Ink Co., Ltd. , "TEP BP-BLACK 1" 1.0 part by weight.

Example 2
A net-like foam was prepared in the same manner as in Example 1 except that the shape of the first base portion of the mold attached to the tip of the second extruder (screw diameter 90 mm) was adjusted. The foaming ratio of the obtained foam was 30 times, the average width W1 of the first linear foam was 6 mm, the average thickness T1 was 2.2 mm, and the average width W2 of the second linear foam was 3.3 mm. The average thickness T2 is 1.7 mm, the distance between the plurality of first linear foams is 140 mm, the distance between the plurality of second linear foams is 150 mm, and the distance between the first linear foam and the second line is 150 mm. The angle of intersection with the shaped foam was 20 °, and curved recesses were formed on the upper surface of the first foam adjacent to the intersection at intervals in the longitudinal direction.

Example 3
A net-like foam was prepared in the same manner as in Example 1 except that the shape of the first base portion of the mold was adjusted. The foaming ratio of the obtained foam was 30 times, the average width W1 of the first linear foam was 9 mm, the average thickness T1 was 3 mm, the average width W2 of the second linear foam was 4.0 mm, and the average thickness. T2 is 2.2 mm, the spacing between the plurality of first linear foams and the plurality of second linear foams is the same as in Example 1, and the distance between the first linear foam and the second line is the same. The angle of intersection with the shaped foam was also the same as in Example 1, and curved recesses were formed on the upper surface of the first foam adjacent to the intersection at intervals in the longitudinal direction.

Comparative Example 1
A net-shaped foam having a substantially circular cross-sectional shape of the first linear foam was prepared in the same manner as in Example 1 except that the shape of the first base portion of the mold was square in cross section.

[Tensile test]
Using a universal testing machine [AGS-X series (manufactured by Shimadzu Corporation)], the tensile strength of the intersection of the net-shaped foams of Examples and Comparative Examples was measured, and the cross-sectional area of the intersection (wide-angle side). The area of the cross section connecting the intersections at) was divided to calculate the joint strength at the intersection. The results are shown in Table 1.

As is clear from Table 1, in the examples, the joint strength at the intersection can be improved by 10 times or more as compared with the comparative example.

[Take-up test]
Test method: The net-like foams obtained in the above Examples and Comparative Examples were wound at a tension of 1.2 kg · m in a direction connecting the intersections on the narrow angle side of the intersection to prepare a wound body. This wind-up body was unfolded into ridges, stretched, left to stand for 24 hours, manually wound up, and the diameter of the wind-up body was measured. By repeating such an operation, the change in the winding diameter of the winding body depending on the number of rewinding was obtained. The average rate of change in the winding diameter indicates the ratio of the average diameter of the winding body to the diameter of the initial winding body. The results are shown in Table 2 and FIG.

As is clear from Table 2, probably because the net-like foam in the comparative example has a large repulsive force against winding, not only the initial winding diameter is large, but also once deployed, a large force is required for winding. At the same time, the diameter of the winding body is increased by about 25% compared to the initial winding diameter. On the other hand, the net-shaped foam of the embodiment is easy to wind up, and the diameter of the wound body does not become so large, so that the storage space and the like can be reduced.

[Moisture transpiration]
60 liters of fruit / flower soil (“Flower and vegetable soil” manufactured by Grinklow Co., Ltd.) was spread in a plastic container (width 77 x depth 58.5 x height 29.5, volume 80 liter size). Then, in order to make the temperature and humidity of the soil uniform, it was dried outdoors for about 10 hours. A black mulch film (“Black Mulch” manufactured by Santera Co., Ltd.) was laid on soil with stable temperature and humidity, and the net-like foam obtained in Example 1 was laid on the black mulch film to form the center of the sample. Water was sprayed 10 times (about 10 ml) with a mist spray from a height of 10 cm, and the water droplets were added so as to be uniform. The transpiration state of the water droplets was visually checked every 5 minutes, and the presence or absence of the water droplets was measured. It was dry after a minute. On the other hand, as a comparative product, when the same test was performed only with the mulch film without laying a net-like foam, a large amount of water pool was found even after 10 minutes, and a small amount of water pool was found after 45 minutes. However, it took 110 minutes to dry.

[Ground heat storage]
60 liters of fruit / flower soil (“Flower and vegetable soil” manufactured by Grinklow Co., Ltd.) was spread in a plastic container (width 77 x depth 58.5 x height 29.5, volume 80 liter size). Then, in order to make the temperature and humidity of the soil uniform, it was dried outdoors for about 10 hours. A black mulch film (“Black Mulch” manufactured by Santhera Co., Ltd.) is laid on soil with stable temperature and humidity, and a net-like foam obtained in Example 1 is laid on the black mulch film, and touch-type data is obtained. A thermocouple was attached to a logger (“TR-H” manufactured by Keyence), embedded in the center of the sample to a depth of 15 cm, and the soil temperature was measured for 24 hours. A Pt thermocouple was used as the thermocouple for measuring the ground temperature, and a K thermocouple was used for measuring the outside air temperature. On the other hand, as a comparative product, the same test was performed only with the mulch film without laying the net-like foam. The measurement result of the soil temperature is shown in FIG. When the net-like foam obtained in Example 1 was laid, the maximum temperature was 33.6 ° C, the minimum temperature was 29.2 ° C, the peak peak temperature (maximum temperature-minimum temperature Δ temperature) was 4.3 ° C, and the average. The temperature was 31.4 ° C. On the other hand, in the comparative product, the maximum temperature was 34.1 ° C., the minimum temperature was 27.7 ° C., the peak peak temperature was 6.4 ° C., and the average temperature was 30.7 ° C. , The heat storage performance was low.

In FIG. 7, comparing Example 1 and the comparative product, Example 1 has a higher minimum temperature and a smaller peak peak temperature, and therefore has excellent ground temperature heat storage, for example, for warming a house in winter. It is expected that the required utility costs will be reduced. The details of the reason why the geothermal heat storage property of Example 1 is superior to that of the comparative product are unknown, but the comparative product has a small strand diameter, so the volume for heat insulation is small, and the comparative product has a circular strand shape, so soil. Since the area of contact with the soil is dotted and the area of the foam that comes into contact with the soil is small, it can be presumed that the point that the heat retention (heat storage) effect is diminished is related.

As described above, the net-like foam of the example has high bonding strength at the intersection and is excellent not only in the take-up property but also in the water transpiration property and the soil temperature heat storage property which are important for strawberry cultivation.

The net-like foam of the present invention has high cushioning property (cucumber property), support or retention property, and breathability to the protected body, and can effectively prevent scratches, so that it can be used for various purposes, especially with fruits. It can be used for contacting purposes such as packaging with melons, watermelons, strawberries, mangoes, tomatoes, avocados, apples, pears, cherries, peaches, plums, grapes, cucumbers, fruitless fruits, loquats, pineapples, blueberries and the like. In a preferred embodiment, the net-like foam of the present invention is suitable for laying on soil (or medium) to grow or cultivate various plants or fruits. If necessary, a net-like foam may be laid on the soil via a film or sheet. For example, the net-like foam of the present invention may be laid on a film or sheet in which a portion corresponding to a stem portion is opened and arranged on soil. The film or sheet may be transparent, and may have light scattering or light absorption, water permeability, moisture resistance, antibacterial property, and the like. The net-like foam may be laid on a flat or sloping soil medium, or may be laid on the ridges of the soil medium.

The fruit is not particularly limited as long as it can be cultivated in contact with a net-like foam, and for example, a fruit or berries (eg, melon, watermelon, strawberry) cultivated in a state where the fruit is in contact with a soil medium. Etc.) are preferable. In particular, it is suitable for cultivating strawberries that are easily scratched and rotted and require uniform coloring.

In such cultivation, the fruit and the net-like foam come into contact with each other to ensure high buffering property and scratch prevention (protective property) for the fruit, and the height space between the soil and the highest linear foam. Therefore, the air permeability and the diffusivity of light can be enhanced, and the growth, coloring and ripening of fruits can be promoted. In particular, since the top-level linear foam has a flat cross-sectional shape and has an upwardly curved shape, it is possible to prevent liquids such as chemicals from flowing down and prevent stagnation, resulting in stable support of fruits and damage. It can be effectively prevented and can prevent corruption and illness. Moreover, since the net-like foam can be wound up to a small diameter and can be easily deployed, the layability of the net-like foam can be improved.

1 ... Net-like foam 2 ... First strand row 3,13 ... First linear foam 4 ... Second strand row 5,15 ... Second linear foam

Claims (10)

It has a strand row formed of a plurality of linear foams arranged in parallel with each other at a predetermined interval, and the plurality of the strand rows are overlapped with each other in a form of intersecting each other, and the linear shape adjacent to each other in the stacking direction. A net-like foam in which the foam is joined at the intersection,
The cross-sectional shape of each of the linear foams is flat, and the upper surface of the linear foam of the strand row located at least at the uppermost portion is downward as it goes toward the linear foams on both adjacent sides. A net-like foam that is curved and has a lower surface that is curved upward corresponding to the upper surface . In each strand row, the expansion ratio M of the linear foam is 5 to 100 times, and the expansion ratio M1 of the linear foam of the strand row located at the uppermost portion and the linear foam of the strand row located at the lower end are The net-like foam according to claim 1, wherein the ratio M1 / M2 to the expansion ratio M2 is 0.7 to 1.3. When the width of the cross section of the linear foam is W and the thickness is T, the aspect ratio (W / T) of the linear foam of the strand row located at the uppermost portion is 2 to 5, and the strand row at the uppermost portion. The net-like foam according to claim 1 or 2, wherein the linear foam of the lower strand row adjacent to the above has an aspect ratio (W / T) of 1.5 to 5. The net shape according to any one of claims 1 to 3, wherein the upper surface of the linear foam of the strand row located at the uppermost portion is formed with a plurality of concave portions and / or convex portions at intervals in the longitudinal direction. Foam. A first strand row formed of a plurality of first linear foams arranged in parallel with each other at predetermined intervals and having a contact surface capable of contacting strawberries, and parallel to each other at predetermined intervals. With a second strand row formed of a plurality of second linear foams disposed in, diagonally intersecting and joined to the first linear foam of the first strand row. It is a net-like foam with
The cross-sectional shapes of the first linear foam and the second linear foam are narrow and flat, respectively.
The contact surface of the first linear foam is gently curved toward the second linear foam as it goes toward both sides of the adjacent first linear foam, and is spaced in the longitudinal direction. Has multiple recesses,
The foaming ratio M of the first and second linear foams is 10 to 50 times, respectively, and the ratio of the foaming ratio M1 of the first linear foam to the foaming ratio M2 of the second linear foam. M1 / M2 is 0.8 to 1.3,
When the width of the cross section of the linear foam is W and the thickness is T, the ratio W1 / W2 of the width W1 of the first linear foam and the width W2 of the second linear foam is 1.5 to 3. The net-like foam according to any one of claims 1 to 4, wherein the aspect ratio (W / T) of the first linear foam is 2.2 to 4. The net-like foam according to any one of claims 1 to 5, wherein the linear foam has substantially the same expansion ratio in each strand row. The linear foams adjacent to each other in the stacking direction are surface-contacted and fused at the intersection, and the bonding strength of the linear foams at the intersection is 10 to 100 N / cm as measured by JIS K6767-1999. ^The net-like foam according to any one of claims 1 to 6. The net-like foam according to any one of claims 1 to 7, wherein a pair of linear foams spread symmetrically from the intersection and can be wound in a direction connecting the intersections of the opposite intersections. The linear foam extruded from each ring die is melted at the intersection while extruding the molten foamable resin composition from the bases formed on a plurality of ring dies that are adjacent to each other in the radial direction and can rotate in opposite directions. The method for producing a net-like foam according to any one of claims 1 to 8, wherein the foam is formed at intervals in the circumferential direction of the ring die on the outermost peripheral side, and the height of the outer peripheral wall is on both sides. Melting from a base portion that is large in the portion and small in the middle portion in the circumferential direction and a base portion having a predetermined length formed at intervals in the circumferential direction of the inner ring die adjacent to the outermost ring die. A manufacturing method for extruding a foamed resin composition. A method for cultivating strawberries by laying the net-like foam according to any one of claims 1 to 8 on soil.

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