JP4848736B2 - Watering tube - Google Patents

Description

  The present invention relates to a water spray tube, and more particularly, a water spray tube made of a thermoplastic resin base material, in which a large number of fine holes are perforated by needle-like protrusions (needles), and the entire surface is subjected to low water pressure conditions. Further, the present invention relates to a water spray tube having fine spray water spray on the entire surface under drip water spray and high water pressure conditions, and having uniform water spray performance in the longitudinal direction.

  In recent years, water spray tubes made of thermoplastic resin have been used instead of hard synthetic resin tubes for watering or irrigation mainly in the fields of agriculture and civil engineering. Usually, these watering tubes are composed of a long thermoplastic resin film with watering holes and a long thermoplastic resin film with the same width that does not have a perforated part, and both ends in the width direction are in the long direction. Bonded type (for example, Patent Document 1) formed by fusing to a tube and a tube obtained by melt-extrusion of a thermoplastic resin from a cylindrical slit by a melt extrusion method and directly forming into a tube shape There is a non-bonding type (for example, Patent Document 2) in which watering holes are formed. The term “film” is used for a film having a thickness of 0.254 mm or less. In the present invention, the term “film” is used as a concept including a sheet.

JP 58-63335 A JP-A-2-258187

Each sprinkling tube is connected to a water supply pipe such as a pump and connected to the water supply with a predetermined water pressure (for example, a water pressure of 0.2 to ² kg / cm ^{2 at} the water sprinkling tube inlet), and a desired water sprinkling amount ( For example, by applying a water spray amount of 20 to 4,000 cc / min · m), a highly accurate drilling process, specifically punch punching method, hot needle drilling method, A number of small holes are regularly arranged with high accuracy by a method such as laser drilling. In general, the perforation diameter (diameter) is about 0.2 to 1.0 mm, the average perforation number density on the tube perforation processing side is about 0.01 to 0.2 per cm ² , and the perforation interval is about 20 to 200 mm.

  However, in recent fields such as raising seedlings, it is impossible to achieve with a sprinkling design that has been designed as perforated as described above. Drip or fine spray on a given field scene or bed (nursery bed) without wetting and hardening the surface or breaking the folds and without physically damaging the leaves and fruits of the crop There is a strong demand for a watering method that achieves a so-called uniform and soft watering state in which watering is performed uniformly in a state.

  As a method for overcoming such a problem, a method of reducing the diameter of the perforations to 0.2 mm or less, preferably 0.1 mm or less is conceivable. However, in such a method, the number of perforations per unit area on the tube surface is limited. As a result, the total area of perforations in the entire tube has been significantly reduced, the amount of water spraying has been greatly reduced, hindering uniform water spraying, and due to the agglomeration phenomenon of dust and inorganic substances mixed in the water source over time. As a result, clogging of the perforated part occurs, and this presents a major problem as a water spray tube in actual use.

In addition, recently, apart from the above, leaves and fruits are not directly wetted with watering, as seen in some straw cultivation methods, pot (potted plant) cultivation methods, and tall cultivation methods. In such a root irrigation method or a liquid manure drip method in which fertilization is efficiently and uniformly applied to a crop, a special tube with a tube folding diameter of about 20-30 mm, a tube tube diameter of about 12-20 mm, and a drip outlet interval of about 50-300 mm A comparatively expensive narrow-width water spray tube (called an infusion tube) incorporating a special seal structure and a special flow path adjusting drip site has become widespread, and has an inlet water pressure of 0.2 to 1 kg / cm ² and a water spray amount of 20 It is being used under conditions of ~ 500cc / min · m.

  However, the conventional spray tube has a problem that the interval between the drip discharge ports is wide, and there is a strong demand for a drip tube that has a further short discharge port interval and can achieve uniform watering as a whole. However, providing an even shorter discharge interval as an extension of the conventional drip tube structure is accompanied by significant technical difficulties in actual manufacturing, and leads to a significant increase in cost. Present.

  Further, in addition to the above, in some of the above-described straw cultivation methods, pot (potted plant) cultivation methods, and tall cultivation methods, root irrigation, liquid fertilization drip, Watering the entire crop is needed.

  However, from the viewpoint of eliminating the tube laying area restriction and reducing the cost of laying the tube, it is desired to use drip watering and fine spray watering with a single watering tube, but it cannot be handled with a conventional watering tube. Is the current situation.

  The present invention has been made in view of the above circumstances, and its purpose is to maintain various characteristics such as durability, pressure resistance, heat resistance, flexibility, workability, and handling convenience, and under the conditions of low water pressure, Another object of the present invention is to provide a watering tube having uniform watering performance in the longitudinal direction, which is finely sprayed on the entire surface under drip watering and high water pressure conditions.

  As a result of intensive studies, the present inventors have compared the conventional watering tube with the watering tube that has been finely perforated with a significantly high perforation number average density on the tube perforation processing surface side by a special perforation method. As a result, the present invention has been completed.

That is, the gist of the present invention is a water spray tube made of a thermoplastic resin base material, and has a perforation number average density on the surface side perforated by needle-like projections having spinous projections on the side. A sprinkling tube characterized in that the average sprinkling amount is 50 / 1,000 cc / min · m in the range of 2 pieces / cm ² or more and measured by laying and inlet water pressure of 0.5 kg / cm ^2. Exist.

  The sprinkling tube of the present invention retains various characteristics such as durability, pressure resistance, heat resistance, flexibility, workability, and handling convenience, and is dripping on the entire surface under low water pressure conditions, and on the entire surface under high water pressure conditions. The performance which has uniform water spraying in the longitudinal direction, which becomes fine spray watering, can be expressed.

  With the watering tube of the present invention, the leaves and fruits of the crop are physically damaged as much as possible over the entire field without damaging the soil surface or breaking the straw by watering. Thus, a so-called uniform and soft watering state is achieved in which water is sprayed uniformly in a drip state or a fine spray state on a predetermined farm scene or bed (nursery bed). Therefore, the watering tube of the present invention works effectively in raising seedlings.

  Furthermore, the sprinkling tube of the present invention has a strong demand for using a single sprinkling tube for drip sprinkling and fine spray sprinkling for the purpose of eliminating tube laying area restrictions and reducing the tube laying cost burden. It works effectively in the law, pot (potted plant) cultivation method and upland cultivation method.

  Hereinafter, the present invention will be described in detail. The watering tube of the present invention comprises a base material made of a thermoplastic resin. As the thermoplastic resin, any resin having flexible flexibility, for example, polyolefin resin, vinyl resin, polyester resin, polyamide resin and the like can be used. Among these, polyolefin resins are particularly preferable.

  Examples of polyolefin resins include polyethylene, ethylene-α-olefin copolymers, ethylene-vinyl acetate copolymers, and mixtures of these resins. The density of polyethylene is usually 0.90 to 0.94 g / cm 3, preferably 0.91 to 0.93 g / cm 3, and the density of the ethylene-α-olefin copolymer is usually 0.90 to 0.94 g. / Cm3, preferably 0.91 to 0.93 g / cm3. The content of vinyl acetate units in the ethylene-vinyl acetate copolymer is usually 1 to 20% by weight, preferably 3 to 15% by weight.

  When each density of polyethylene and ethylene-α-olefin copolymer is lower than the above range, the mechanical strength of the perforated tube is lowered, and durability, pressure resistance, and heat resistance may be inferior, and higher than the above range. If it is too high, the flexibility of the perforated tube may be impaired, which may hinder storage during storage, uniform water spraying during watering, and handling convenience. Moreover, when there is more content of the vinyl acetate unit of an ethylene-vinyl acetate copolymer than said range, the mechanical strength of a perforated tube will become low and durability, pressure resistance, and heat resistance may be inferior.

  Examples of the α-olefin used for the production of the ethylene-α-olefin copolymer resin include propylene, butene-1, hexene-1, 4-methylpentene-1, octene-1, and the like. As such, any of a polymerization method using a Ziegler catalyst or a polymerization method using a metallocene catalyst may be used.

  Further, the melt index (measurement method: conforming to JIS K7210, temperature: 190 ° C., load: 2160 g) of the above polyolefin resin is usually 0.1 to 50 g / 10 minutes, preferably 0.2 to 20 g / 10 minutes. It is. When the melt index is lower than the above range, the molten resin at the time of extrusion processing is too high in viscosity, resulting in poor extrusion processability and may cause poor appearance of the obtained tube surface. On the other hand, when the melt index is higher than the above range, it is difficult to obtain stable molding processability because the viscosity is too low, and the mechanical strength of the tube itself is lowered, resulting in inferior durability, pressure resistance, and heat resistance. is there.

  To the thermoplastic resin used in the present invention, carbon, a weather stabilizer, an antioxidant and the like can be appropriately added in advance for the purpose of improving the durability and weather resistance of the perforated tube. In addition, various additives such as inorganic fillers, lubricants, pigments, dyes, antistatic agents, and plasticizers can be appropriately added as necessary.

  As a tube forming method, a thermoplastic resin is extruded from a cylindrical slit by a melt extrusion method and cooled, and the obtained tube is folded into a flat shape by a pinch roll and formed into a tube shape. After extruding a thermoplastic resin through a straight flat slit, it is cooled to obtain a film, and two sheets of the obtained film are overlapped, and both ends in the width direction are fused and bonded in the longitudinal direction to form a tube The method of forming is mentioned. The molding temperature is usually about 130 to 220 ° C.

  In addition, as said tube shaping | molding method, a cylindrical slit is enlarged, the both ends of the obtained tube are cut | disconnected, two wide films are obtained, slit into predetermined width | variety, and then two tapes Alternatively, a method may be employed in which the film-like films are stacked and fused and bonded to form a tube shape. In that case, when two tape-like films are overlapped, a thermoplastic resin sheet having a dust capturing filter function mixed in the water source may be interposed between the two tape-like films to be fused and bonded. .

  The size of the watering tube of the present invention is not particularly defined, but the thickness is usually 0.1 to 0.8 mm, preferably 0.2 to 0.6 mm, and the folding diameter is usually 10 to 80 mm, preferably 15 to. The diameter of the tube is usually 6 to 50 mm, preferably 10 to 40 mm.

  The perforation part which comprises the watering tube of this invention is given by the perforation process by a needle-like protrusion. FIG. 1 is an explanatory diagram of an example of a boring apparatus used in the present invention. The illustrated drilling apparatus is functionally constituted by a feeding unit, a drilling unit, and a winding unit. The feeding part is mainly composed of a feeding roll (1) around which a work material is wound, and the punching part is a needle roll (2) in which a large number of needles are embedded and a presser roll (3) comprising a rubber roll or a metal roll. ), And the winding part is mainly composed of a winding roll (4) around which the work material is wound. Two needle rolls (2) are arranged, but may be one. The perforating apparatus having the above-described structure is known as a needle punching apparatus in a woven fabric raising process step, for example.

  The tube-shaped or planar (non-tube-shaped) non-perforated film (5a) is fed from the feeding roll (1), processed in the perforating section, and taken as the perforated film (5b) by the winding roll (4). It is wound up. The perforated film (5b) wound around the take-up roll (4) can also be fed from the take-up roll (4) side to the feed roll (1) for re-perforation.

  When the unperforated film (5a) is a flat (non-tubular) film, a perforated film having a large number of perforated portions is prepared by the perforating apparatus, and this is overlapped with the non-perforated film. A watering tube can be obtained by fusing and pasting both ends in the longitudinal direction. Such a method can be used when a non-perforated film is disposed between a perforated film and a non-perforated film to produce a watering tube with a filter function.

  Control of the diameter of the drilling hole and suppression of unexpected penetration of needle-like projections on the tube surface opposite to the insertion and surface damage can be achieved by the gap between the needle roll (2) and the presser roll (3) and presser pressure. By finely adjusting the distance, the insertion distance from the tube outer surface of the needle-like projection can be changed.

  The shape and size of the needle-shaped projections used for the drilling process have a direct influence on the shape and diameter of the drilled portion of the watering tube to be obtained, and are particularly limited as long as the desired watering tube can be obtained. Not.

  However, based on the idea of the present inventors based on the idea of a fabric texture improving processing machine `` needle pricker '' used in the fields of nonwoven fabric, leather, woven fabric, etc. Apart from the conical or pyramidal acicular protrusion, an acicular protrusion having a spinous process on the side is preferred.

  FIG. 2 is an explanatory view of a needle-like protrusion having a spinous process on the side. The needle-like projection (21) exemplified in (a) has one spinous process (a), and the needle-like projection (21) exemplified in (b) has two spines oriented in the same direction. The needle-like protrusion (21) illustrated in (c) has protrusions (a) and (a), and has two spinous processes (a) and (a) oriented in opposite directions. Reference numeral (20) represents an embedded portion in the needle roll (2).

  Said needle-like protrusion (21) is pointed toward the front-end | tip from the base, The whole length is 1-10 mm normally, Preferably it is 2-6 mm. The length of the spinous process itself having a tearing property is usually 0.01 to 0.30 mm, preferably 0.03 to 0.15 mm, and the number of spinous processes is plural, for example, 2-3. Is preferred. The position of the spinous protrusion is usually 0.3 to 2.0 mm from the tip of the needle-like protrusion (21). For example, one spinous process is provided at a position 0.3 to 1.0 mm from the tip of the needle-like projection (21), and 0.6 to 2.0 mm from the tip of the needle-like projection (21). One other spinous process can be provided at the location.

  When a needle-like projection having a spinous process on the side is used for the drilling process, the shape of the obtained perforated part is not circular, but has a shape having a spine-shaped tearing part on the peripheral side of the hole. For example, an extremely fine cut portion of about 0.005 to 0.02 mm is formed in the perforated portion of the watering tube. Such a sprinkling tube having a perforated part of a special shape can generate drip sprinkling on the entire surface under low water pressure conditions, and can exhibit finer and softer fine spray watering on the entire surface under high water pressure conditions. It becomes easy.

In the water spray tube of the present invention, the average density of the number of perforations on the surface side perforated by the needle-like protrusions is 2 pieces / cm ² or more, preferably 5 pieces / cm ² or more. The average number of holes perforated in this case is recognized as a perforated part penetrating by an observation method using a magnifying means such as a microscope on the tube perforation processing surface side. The number of perforated portions where spray watering is recognized is defined as the number per unit area (1 cm ² ).

When the average number of perforations on the tube perforation surface side is smaller than 2 pieces / cm ² , there are the following problems. That is, in the fine perforation form having a perforation number average density as described above, for example, a perforation diameter of 0.10 mm or less, the number of perforations per unit area on the tube surface is limited. There is a concern that the amount of sprinkling will be significantly reduced and the amount of water sprayed will be greatly reduced, and the clogging phenomenon of the perforated part will occur due to the influence of the agglomeration phenomenon over time of dust and inorganic substances mixed in the water source. The upper limit of the average number of perforations is usually 500 / cm ² .

  The distribution state of the fine perforations on the perforated surface side is not particularly limited, and the length of the fine perforations may be uniformly dispersed over the entire surface on one side of the tube, as long as it does not hinder uniform water spraying. The fine perforations may exist at a certain periodic interval (for example, an equal interval in the range of 20 to 100 mm) on one side of the tube in the direction, and the fine perforations may be concentrated in a specific area.

  Actually, the size and area of the perforated portion of the watering tube should be discussed in a state where the watering tube is laid and a predetermined water pressure is applied. The sprinkling amount is deeply related to the sprinkling tube inlet water pressure and the total perforated area per unit length of the sprinkling tube. Specifically, the sprinkling amount is higher as the sprinkling tube inlet water pressure is higher. The larger the perforated part total area per unit length, the larger the value.

Therefore, in the present invention, as one of the characteristics of the watering tube of the present invention, the average watering amount laid and measured under the condition of the inlet water pressure of 0.5 kg / cm ² is 50 to 1,000 cc / min · m. It stipulates that it is in the range of.

  When the above average watering rate is less than 50 cc / min · m, the watering rate is much too small, and it has hindered uniform watering in actual use, while the above average watering rate is 1,000 cc / min.・ If it is larger than m, the amount of sprinkling is significantly too large, and a certain amount of water pressure is applied near the inlet of the installed watering tube, but the water pressure is greatly reduced near the end, and as a result Uniform water spray in the direction cannot be expressed. A preferable range of the average water spray amount is 80 to 800 cc / min · m.

Incidentally, regarding the watering tube of the present invention described above, the minimum diameter of the perforated part is usually 0.10 mm or less, preferably when the perforated diameter or shape is simply observed by an enlargement means such as a microscope without applying a predetermined water pressure. Is 0.08 mm or less. With a large shape with a perforated diameter exceeding 0.10 mm, it is impossible to obtain water spraying performance such as drip spraying over the entire surface under the target low water pressure conditions, and fine spray water spraying over the entire surface under the high water pressure conditions. The watering characteristics are similar to a thread-like watering with a relatively strong water volume. Moreover, in such a perforation form with a perforation diameter of ² or more per cm ² on the tube perforation processing surface side, the total perforation area of the entire tube is remarkably large, and the amount of sprinkling is greatly increased. As a result, uniform water spraying in the longitudinal direction cannot be achieved.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further in detail, this invention is not limited to a following example, unless the summary is exceeded.

Example 1:
As the resin material, a polyolefin resin composition (A) having a composition of 97 parts by weight of a high pressure polymerization polyethylene resin having a melt index of 1 g / 10 min and a density of 0.92 g / cm ^{3 and 3} parts by weight of carbon black was used. Then, melt extrusion molding was performed using an air-cooled inflation film molding apparatus (melt extrusion temperature: 160 ° C.) to produce a tubular film having a thickness of 0.30 mm, a folding diameter of 25 mm, and a tube diameter of 16 mm.

The above tubular film is continuously passed through a punching device similar to that shown in FIG. 1 (the punching portion is composed of two needle rolls of one presser rubber roll), and the roll presser pressure (needle insertion pressure setting) is 6 kg. A watering tube having a large number of perforations was prepared by perforating under the conditions of / cm ² . The number of needles implanted on the surface of the needle roll is 32 / cm ² , and the needle-like projections having the shape shown in FIG. 2B and the spinous projections having the specifications shown in Table 1 are used as the needle-like projections. did.

As a result of observing the perforated part of the sprinkled tube obtained with a microscope, the perforated part has a fine spine-shaped tear part, the minimum diameter of the perforated part is 0.025 mm, and the number of perforations on the tube perforated surface side The average density was 64 / cm ² .

Moreover, the average watering amount (cc / min · m) when the above-mentioned watering tube was laid in the field at a length of 50 m and water pressure was applied so that the inlet water pressure was 0.5 kg / cm ² was measured. In addition, when water pressure is applied, the water pressure at the inlet and the end is measured at a predetermined watering amount of 10, 20, 30 liters / minute / 50 m, and the watering shape from the watering tube (instillation water spray state, fine spray state, filamentous water spray state) ), The behavior of uniform water spray was observed. The results are shown in Table 2.

Example 2:
As a resin material, a melt index of 2 g / 10 min, a density of 0.92 g / cm ³ of ethylene- (4 methylpentene-1) copolymer resin 47 parts by weight, a melt index of 1 g / 10 min, and a vinyl acetate unit content of 10 A polyolefin resin composition (B) comprising a composition of 50% by weight of an ethylene-vinyl acetate copolymer resin and 3 parts by weight of carbon black was used. Then, melt extrusion molding is performed using an air-cooled inflation film molding apparatus (melt extrusion temperature: 160 ° C.), and both ends of the obtained tube are cut, and a film having a film thickness of 0.25 mm and a film width of 600 mm (A )created.

The above film is continuously passed through a punching apparatus similar to that shown in FIG. 1 (the punching portion is composed of two needle rolls of one presser rubber roll), and roll presser pressure (needle insertion pressure setting) 4 kg / cm ^After perforating under the conditions of ² and winding, the same process (the same direction of needle insertion into the film surface) was repeated again to produce a perforated film (B) having a number of perforated portions. The number of needles implanted on the surface of the needle roll and the used needle-like protrusions are the same as those in Example 1.

And using said film (A), perforated film (B), and non-woven fabric (C) (material: polyethylene + polypropylene, thickness: 0.25 mm, basis weight: 50 g / m ² ), filter in the following manner A watering tube with a function was produced.

  That is, each of the above films (A) and (B) is slit to a width of 42 mm, the size of the nonwoven fabric is adjusted to the size of these films, and the nonwoven fabric (between the film (A) and the perforated film (B) ( C) was interposed and fused and bonded. The tube folding diameter of the watering tube was 36 mm, and the tube diameter was 23 mm.

As a result of observing with a microscope the perforated part of the sprinkling tube obtained (inserted with a needle from the tube surface and perforating), the perforated part had a fine spine-shaped tear part and the minimum diameter of the perforated part was 0. The average density of the number of perforations on the tube perforation processed surface side was 020 mm / cm ² . Table 2 shows the results of tests conducted in the field as in Example 1.

Example 3:
Using the same resin material (polyolefin resin composition (B)) as in Example 2, a film (A) having a film thickness of 0.25 mm and a film width of 600 mm was prepared by the same method as in Example 2. did.

The above film is slit to a width of 42 mm, and a roll gap (needle insertion setting) 0 is inserted into a punching apparatus similar to that shown in FIG. 1 (the punching portion is composed of one presser metal roll and one needle roll). . Perforated film (D) having a large number of perforated portions was continuously passed under the condition of 0.5 mm. The number of needles implanted on the surface of the needle roll was 10 / cm ² , the needle arrangement was 4 rows, and the needle-like protrusions having a length of 3 mm without the spinous protrusions were used.

  Next, as in Example 2, the non-woven fabric (C) was interposed between the film (A) and the perforated film (D) to be fused and bonded, and the filter function with a folding diameter of 36 mm and a tube tube diameter of 23 mm was provided. A watering tube was prepared.

As a result of observing with a microscope the perforated portion (perforated by inserting a needle from the tube surface) of the watering tube obtained, there was no spinous cut around the perforated portion, the minimum diameter of the perforated portion was 0.060 mm, and the tube The average number of perforations on the perforated surface side was 10 holes / cm ² . Table 2 shows the results of tests conducted in the field as in Example 1.

Comparative Example 1:
In Example 3, a watering tube with a filter function having a folding diameter of 36 mm and a tube diameter of 23 mm was prepared in the same manner as in Example 3 except that the number of needles implanted on the surface of the needle roll was changed to 0.10 / cm ^2. did.

As a result of observing with a microscope the perforated portion (perforated by inserting a needle from the tube surface) of the watering tube obtained, there was no spinous cut around the perforated portion, the minimum diameter of the perforated portion was 0.060 mm, and the tube The average density of the number of perforations on the perforated surface side was 0.10 pieces / cm ² . Table 2 shows the results of tests conducted in the field as in Example 1.

Comparative Example 2:
Using the same resin material (polyolefin resin composition (B)) as in Example 2, extrusion molding was performed with an air-cooled inflation film molding apparatus (melt extrusion temperature: 160 ° C.), and both ends of the tube were cut. And a planar film having a film thickness of 0.25 mm and a film width of 600 mm was prepared.

  The above planar film is slit to a width of 42 mm, and the laser output and drilling position are adjusted by the YAG laser drilling device so that it is finished in the predetermined drilling design (hole array: staggered in 4 rows, 25 mm intervals). A perforated film (E) having a large number of perforated portions was prepared.

  Next, as in Example 2, the non-woven fabric (C) was interposed between the film (A) and the perforated film (E) to be fused and bonded, and the filter function with a folding diameter of 36 mm and a tube tube diameter of 23 mm was provided. A watering tube was prepared.

As a result of observing the perforated part of the sprinkled tube obtained with a microscope, the minimum diameter of the perforated part was 0.20 mm (true circle), and the average number of perforations on the tube perforated surface side was 0.11 per cm ^2. It was. Table 2 shows the results of tests conducted in the field as in Example 1.

  In Table 2 below, the determination of “good” or “bad” of the uniform watering behavior at a predetermined watering amount is based on the visual observation of the uniform state of the field wetting in the length direction of the tube laying. Judgment was carried out. In addition, “−” described in Comparative Example 1 indicates that the original pressure needs to be set abnormally high in order to achieve the predetermined watering amount, which is inappropriate for actual watering.

Explanatory drawing of an example of the boring apparatus used by this invention Explanatory drawing of the acicular protrusion which has a spinous process in a side part

Explanation of symbols

1: Feed roll 2: Needle roll 3: Presser roll 4: Winding roll 5a: Non-perforated film 5b: Perforated film 20: Embedding portion 21: Needle-like protrusion a: Spinous process

Claims (1)

A sprinkling tube made of a thermoplastic resin base material, the average number of perforations on the surface side perforated by needle-like projections having spinous projections on the side is 2 / cm ² or more , watering tube average watering amounts measured under the conditions of inlet water pressure 0.5 kg / cm ² by laying is being in the range of 50～1,000Cc / min · m.

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