CN1675985B - Farm film - Google Patents

Abstract

The present invention provides an agricultural film excellent in anti-fogging properties and moisture permeability, which is used for inner or outer laying of cultivation in plastic sheds, cultivation in plastic tunnels, and the like. The present invention relates to an agricultural film, characterized in that it has a plurality of fine holes obtained by perforating a thermoplastic resin film with a needle having a thorn-like protrusion; or it is a thermoplastic resin with a plurality of fine holes, characterized in that , the shape of the micropores is a thorny shape with thorns, and preferably the total light transmittance at 555 nm of the film having a plurality of such micropores is greater than or equal to 70%.

Description

Agricultural film

technical field

The present invention relates to an agricultural film for inner or outer covering of cultivation in plastic sheds and plastic tunnels, and in particular to an agricultural film excellent in anti-fog and moisture permeability.

Background technique

In the past, the method of accelerating the cultivation of crops was mainly to cultivate plants under the cover of agricultural films such as vinyl chloride resin films or olefin resin films, that is, cultivation in plastic sheds and cultivation in plastic tunnels.

In such plastic shed cultivation and plastic tunnel cultivation, etc., the temperature and humidity in the plastic shed and plastic tunnel have a great influence on the growth of crops, so it is necessary to adjust it according to the climate.

Especially in the cultivation of large-scale plastic greenhouses in recent years, in addition to the agricultural film for outer laying that is fixedly spread on the frame of the greenhouse, the agricultural film for inner laying is also used as a so-called shading material or as a whole that further covers the shape of the crops inside the greenhouse. shade material.

In particular, if the moisture permeability (air permeability) of this kind of agricultural film for inner laying is low, the water vapor in the warm air will fill the inside of the film, which may cause damage to crops due to excessive humidity. In addition, water vapor adheres to the inside of the film to form water droplets, and as a result, the transparency of the film decreases, so moisture permeability (breathability) and anti-fogging properties become necessary.

In addition, agricultural films for coverings are preferably films that have air permeability (moisture permeability) in addition to insect repellency and rain resistance, but agricultural films for coverings that have such air permeability have not yet been obtained. The anti-fogging property of the agricultural film used for spreading outside is an important performance. In the past, the method of spraying anti-fogging agent on the inner side when the plastic shed was spread, the method of mixing surfactants on the inner side of the film, and the method of coating the inner side of the film with There are other methods of coating layers of special inorganic fine particles, etc., but these methods require manpower and cost, and sufficient anti-fog properties cannot be obtained.

Previously, non-woven fabrics of agricultural materials with air permeability were used in agricultural films for inlays. Non-woven fabrics have excellent air permeability, but they are composed of white opaque raw materials, so they have the disadvantage of low light transmittance, and they cannot be used because light is necessary for crops during the growth period.

There have also been proposed several agricultural films in which air-permeable holes and water-permeable holes are provided on a non-porous film formed of a synthetic resin film. For example, Japanese Unexamined Patent Publication No. 5-74249 discloses an agricultural film provided with vent holes with a diameter of 1.5 mm or less and the total area of the vent holes accounts for 10% to 60% of the surface area of the film. Publication No. 5-10598 discloses a kind of agricultural perforated film for shading in the inner shop. In order to eliminate the water droplets condensed on the inner side of the outer covering material and fall on the shade cloth in the inner shop to form water flow, the so-called gold For the fish tank phenomenon, at least one through hole with a diameter of 1 mm to 4 mm is provided on every 1 m ² area of the synthetic resin film as a through hole for removing water. And as the perforation method, a needle perforation method of perforating with a needle has also been proposed.

However, the conventional perforated films have contradictory problems, that is, in order to achieve waterproof and heat retention, it is necessary to reduce the size of the holes, but this will cause the disadvantage of not being able to breathe fully, but if the size of the air holes is increased to ensure air permeability , there will be problems that reduce the waterproof and insect-proof effect and the heat preservation effect.

Contents of the invention

The object of the present invention is to provide an agricultural film having moisture permeability (breathability), anti-fogging properties, anti-droplet adhesion, heat retention and waterproof and insect-proof effects without reducing transparency.

The inventors of the present invention found that the object of the present invention can be achieved by using a thermoplastic resin film having a plurality of micropores formed by punching with a needle of a special shape, and completed the present invention.

That is, the gist of the present invention is (1) an agricultural film characterized in that it has a plurality of fine holes obtained by perforating a thermoplastic resin film with a needle having a thorn-like protrusion; or (2) an agricultural film characterized in that In that, it is a thermoplastic resin film with a plurality of micropores, and the shape of the micropores is a thorny shape with thorns; or (3) an agricultural film, characterized in that it is a thermoplastic resin film with a plurality of micropores For thin film, the tiny hole is obtained by punching a needle. The relationship between the surface roughness Ra1 of one side of the film and the surface roughness Ra2 of the other side of the film is Ra1<Ra2. Inner side; or (4) the agricultural film as described in (1) or (2), characterized in that it has a plurality of micropores, and the micropores are made from both sides of the thermoplastic resin film by needles having thorn-like protrusions. or (5) the agricultural film as described in (1) or (2), which is characterized in that it is a thermoplastic resin film with a plurality of micropores obtained by piercing with needles, and the two sides of the film have Micro protrusions; or (6) the agricultural film as described in any one of (1) to (5), characterized in that the total light transmittance at 555 nm of the film with a plurality of micro pores is greater than or equal to 70%; or ( 7) The agricultural film as described in any one of (1) to (6), wherein the resin constituting the thermoplastic resin film is vinyl chloride resin or olefin resin; or (8) such as (1) to (7) ) according to any one of the agricultural films, characterized in that the thermoplastic resin film is a resin film having at least three or more layers of an outer layer, an intermediate layer, and an inner layer, and constitutes an outer layer And/or the resin of the inner layer contains at least a metallocene-based polyethylene resin.

Utilizing the present invention, an agricultural film having moisture permeability (breathability), anti-fogging properties, anti-droplet adhesion, heat retention, and waterproof and insect-proof effects can be obtained without reducing transparency.

Description of drawings

Fig. 1a is a front view of a needle having thorn-like protrusions for forming micropores of the present invention.

Fig. 1b is a side view of a needle having thorn-like protrusions for forming micropores of the present invention.

Fig. 2 is a schematic diagram of thin film processing using the needle for forming micropores of the present invention.

Fig. 3 is a schematic view showing the shape of micropores formed in the thermoplastic resin film of the present invention.

Fig. 4 is a schematic diagram of a cross-sectional view of the shape of micropores formed in the thermoplastic resin film of the present invention.

Fig. 5 is a schematic diagram of a thermoplastic resin film provided with a plurality of thorn-shaped micropores having thorns according to the present invention.

Detailed ways

The present invention will be described in detail below.

The agricultural film (moisture-permeable film, anti-fog film) of the present invention is a porous resin film in which a plurality of micropores are provided in a thermoplastic resin film.

As the resin constituting the thermoplastic resin film, for example, polyolefin resins such as vinyl chloride resin, polyethylene, ethylene-vinyl acetate copolymer, and polypropylene, polyester resins such as polyethylene terephthalate, polymethyl Methyl acrylate resins, fluorine-containing resins, and other thermoplastic resins known conventionally as materials for agricultural films, moisture-permeable films, and anti-fogging films. It is preferable to use soft vinyl chloride resin and polyolefin resin.

Polyolefin resins include homopolymers of α-olefins, copolymers of different types of monomers with α-olefins as the main component, polyunsaturated compounds such as α-olefins and conjugated dienes or non-conjugated dienes, acrylic acid, Copolymers of methacrylic acid, vinyl acetate, etc., such as high-density, low-density or linear low-density polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-butene copolymer, ethylene-4- Methyl-1-pentene copolymer, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, etc. Among them, low-density polyethylene with a density of 0.910 to 0.935, ethylene-α-olefin copolymers, and ethylene-vinyl acetate with a vinyl acetate content of 30% by weight or less are preferred in terms of transparency, weather resistance, and price. Copolymers are used as agricultural films.

One of the preferred aspects of the present invention is an agricultural film that is provided with a plurality of micropores and maintains high strength according to the usage site requiring a certain strength and the number of years of use. As the high-strength agricultural film, at least one component of the resin constituting the thermoplastic resin film is preferably a metallocene polyethylene resin, that is, an ethylene-α-olefin copolymer resin obtained by copolymerization using a metallocene as a catalyst. The substance is commonly called metallocene polyethylene, which is a copolymer of ethylene and alpha-olefins such as 1-butene, 1-hexene, 4-methyl-1-pentene, octene, etc. Can be made.

The metallocene-based polyethylene resin is further preferably one having the following physical properties. The MFR measured by JIS-K7210 is 0.01g/10 minutes to 10g/10 minutes, preferably 0.1g/10 minutes to 5g/10 minutes; the density measured by JIS-K7112 is 0.880g/cm ³ to 0.930g/cm ³ , preferably 0.880g/cm ³ to 0.920g/cm ³ , and the molecular weight distribution (weight average molecular weight/number average molecular weight) measured by gel permeation chromatography (GPC) is 1.5 to 3.5, preferably 1.5 to 3.0.

In the preferred state of the agricultural film in the present invention, the base film formed of the polyolefin resin composition is made into a multilayer film having at least three or more layers of an outer layer, an intermediate layer, and an inner layer when it is spread out. . A resin composition containing 45% by weight to 100% by weight, preferably 55% by weight to 95% by weight, of an ethylene-α-olefin copolymer resin is used as the resin component of the outer layer or the resin components of the outer layer and the inner layer when spread. , the ethylene-alpha-olefin copolymer resin is obtained by copolymerization using a metallocene as a catalyst. The middle layer or the middle layer and the inner layer preferably use a resin composition containing 45% by weight to 100% by weight, preferably 55% by weight to 98% by weight of an ethylene-vinyl acetate copolymer.

The outer layer referred to here refers to the outer layer when used as an agricultural film, and the inner layer refers to the inner layer when used.

There is no particular limitation on the method for producing the resin film of the multilayer structure, and known production methods can be used. The thickness ratio of the layers in the multilayer structure is not particularly limited. For example, in the case of a three-layer structure, from the aspects of formability, From the viewpoint of transparency and strength, the thickness ratio of the layer is preferably in the range of 1/0.5/1 to 1/5/1, more preferably in the range of 1/2/1 to 1/4/1. In addition, the ratio of the outer layer to the inner layer is not particularly limited, but it is preferably an equivalent ratio from the viewpoint of curlability of the obtained film.

The thickness of the thermoplastic resin film is 10 microns to 1000 microns, preferably 20 microns to 200 microns. If it is too thin, the strength of the perforated film tends to be insufficient. If it is too thick, the punching process will become difficult, so it is not preferable.

Any known additives may be blended in the thermoplastic resin film used in the present invention according to the application. For example, various additives such as plasticizers, UV protection agents, light stabilizers, heat insulating agents, lubricants, etc.

In addition, other coating films may be formed on the agricultural film of the present invention. For example, a dust-proof coating can be formed on the outer layer of the film. If an anti-fog coating is formed on the inner layer of the film, it will have a synergistic effect with the effect of the micropores of the present invention, and a good anti-fog effect will be obtained. As the anti-fog coating film, coating anti-fog coating films of various known agricultural films can be used, but inorganic sols such as silica sol and/or alumina sol, and binder resins such as thermoplastic resins as main components are preferable. composition etc. Examples of thermoplastic resins include hydrophobic or hydrophilic acrylic resins, polyurethane resins, and the like.

As the agricultural film to which the present invention is applied, there can be mentioned the film for inner or outer laying in cultivation in plastic shed or plastic tunnel cultivation, the full shade film directly covering plants, other lamination films, etc., especially preferably inner laying or outer laying Use film.

The present invention is characterized in that the micropores provided in the thermoplastic resin film are special micropores. Specifically, the special micropores are formed by a piercing method using a special needle, which applies a mechanical needling process mainly used for texture processing of non-woven fabrics, fabrics, and artificial leather.

Specifically, as shown in the schematic diagram of FIG. 1, the micropores are obtained by piercing the thermoplastic resin film with a special-shaped needle 1 having at least one tiny thorn 1c on the outer periphery.

Fig. 1 is an enlarged view of the needle 1, Fig. 1a shows a front view, and Fig. 1b shows a side view. The needle 1 is tapered from the base 1a toward the most distal end, and has a cutting edge 1b of a small width (W) at the most distal end. The minute width at the tip is related to the size of the basic part of the pores formed in the resin film, and is preferably 10 to 300 microns, more preferably 30 to 150 microns.

The special needle 1 used in the present invention is provided with one or more, preferably two or more, tiny thorns 1c on a part of the outer periphery of the needle near the front end. The thorn protrudes toward a direction close to a right angle with respect to the needle axis, and the shape of the thorn is also from the base toward the front end, forming a pointed shape. For example, a thorn 1c is set at a distance from the front end of the needle 300 microns to 1000 microns, then preferably at Set another thorn at 800 microns to 2000 microns. The length of the spines 1c itself is preferably 1 micrometer to 300 micrometers.

As shown in Figure 2, preferably a plurality of these needles 1 with thorns are installed on the roller body 2 to form a needle roller 2, and this needle roller is pressed against the processed thermoplastic resin film placed on a plane or wound on other roller bodies 3, so that a plurality of microscopic holes can be formed on the thermoplastic resin film. The resin film 3 may be processed with a plurality of needle rolls depending on the number and spacing of the required fine pores, or may be processed by pressing the resin film against the needle rolls several times. One of the preferred aspects of the present invention is a method of perforating a resin film from both sides as will be described later, and this method can reduce curling of the film. In this case, both sides can be processed at the same time, but it is usually easier to process one side at a time.

Fig. 3 is a schematic diagram showing the shape of each micropore formed on a thermoplastic resin film by using a needle of a special shape. The shape of the micropores can be confirmed using a magnifying tool such as a microscope. Due to the existence of thorns 1c, the shape of the micropores 4 formed on the film of the present invention is not the circular hole shape formed by ordinary needles, but as shown in the schematic diagram of Figure 3, in the basic hole of a quasi-circle 4a has a star-like shape with one or more than one tiny spiny incision site 4b surrounding it. Form one or more than one thorn-shaped incision site, preferably form two or more thorn-shaped incision sites. In most cases, the number of thorn-shaped incision sites is the same as the number of thorns 1c on the needle 1 used. The number is the same as or greater than the number of spines 1c.

The mechanism of the excellent anti-fog effect and moisture permeability effect of the present invention is not clear, but it is presumed to be due to the synergistic effect of the shape produced by the connection of the basic hole part with a large gap and the thorn-shaped cut part with a small gap.

Regarding the diameter of the fine pores, it is preferable that the maximum diameter of the basic pores 4a is less than or equal to 500 microns, preferably less than or equal to 200 microns, and the smallest diameter is greater than or equal to 10 microns, preferably greater than or equal to 20 microns. The length of the thorn-shaped cut site 4b is preferably 0.05 micron to 50 micron, more preferably 0.1 micron to 20 micron.

Fig. 5 is a schematic view showing a film provided with a plurality of micropores of the present invention.

When the barbed needle penetrates the resin film and pulls it out, it has the function of hooking the film around the incision site and making the slice 4c around the thorn-shaped incision site 4b protrude along the direction in which the needle penetrates. Therefore, a film having a plurality of micropores obtained by the method of piercing with a special needle of the present invention has a special shape when viewed from the cross section of the film.

Fig. 4 is a schematic diagram of a cross-sectional view of the micropores provided on the film of the present invention. In the resin film 3, a part of the slice 4c around the puncture-shaped cut site 4b of the micropores has some protrusions along the acupuncture direction. shape.

As a result, in the film having micropores of the present invention, the surface roughness Ra1 of the film surface (P in FIG. 4 ) on the side where the needle penetrates is compared with the roughness Ra2 of the film surface (Q in FIG. 4 ) on the opposite side. , Ra1<Ra2. In this case, Ra1 is close to the surface roughness of the original film. In addition, depending on the thickness of the film, the surface roughness Ra2 is different, which is that the relationship between the film thickness (Ha) and the protrusion height (Hc) on the film surface along the needle penetration direction is Hc/Ha=0.4～2, preferably 0.5 Surface roughness of ~1 degree.

When using the agricultural film of the present invention, basically any side of the film can be used as the inner side, but the preferred method of use is if the side with anti-fogging properties or the side with high humidity are arranged with a side with a large surface roughness. On one side (Ra2), the desired effect can be obtained.

Another preferred aspect of the agricultural film of the present invention is a double-side perforated film obtained by punching a thermoplastic resin film from both sides. Perforating from both sides can reduce the curling of the film in one direction. In addition, the same conditions may be adopted for the perforation process on both sides, or different conditions (size and density of holes) may be adopted.

The number per unit area of the plurality of micropores provided on the thermoplastic resin film of the present invention varies according to the area of the provided holes, but preferably in order to show anti-fogging properties and moisture permeability while satisfying other physical properties, preferably There are 800 to 8000 pieces per 1 square inch (6.45 square centimeters) (ie, 125 to 1250 pieces per 1 square centimeter), more preferably 1500 to 6000 pieces per 1 square inch (ie, 230 to 930 pieces per 1 square centimeter). indivual).

In addition, in order to use as an agricultural film, it is more preferable that the thermoplastic resin film provided with the micropore of the special shape of this invention has transparency. Specifically, the total light transmittance at 555 nanometers of the film with a plurality of micropores is greater than or equal to 70%, preferably greater than or equal to 75%. This value is measured according to a well-known measuring method.

Example

Hereinafter, the present invention will be described in detail, but the present invention is not limited to the following examples unless the above-mentioned gist is exceeded.

(1) Modulation of base film

The thermoplastic resin film used in the test was a laminated film (0.05 mm thick) of the following two kinds of polyolefin resins (three-layer structure formed by a three-layer inflation die) as a base film.

Film 1: The following film is used as the base film. Contains an appropriate amount of various additives commonly used in agricultural films, such as thermal insulation (hydrotalcite), ultraviolet absorbers, light stabilizers, etc., and the outer resin is linear low-density polyethylene (LLDPE) and low-density polyethylene (LDPE) ), the middle layer resin is a vinyl acetate resin with a vinyl acetate content of 15% by weight, and the inner layer resin is a vinyl acetate resin with a vinyl acetate content of 5% by weight.

Film 2: The following film is used as the base film. It contains various additives such as thermal insulation agent (hydrotalcite), ultraviolet absorber, and light stabilizer. The outer layer resin and inner layer resin are mainly composed of polyethylene resin (MePE) produced with metallocene as a catalyst (90 wt. %) polyethylene resin, the middle layer resin is a vinyl acetate resin with a vinyl acetate content of 15% by weight.

(2) Needle processing method

As an example, the following films were prepared. By the perforation method carried out with a plurality of thorn needles of the shape shown in FIG. 1 on the roller shown in FIG. ), 2030 holes (embodiment 2), 4060 holes (embodiment 3), 6190 holes (embodiment 4).

Similarly, as an example, a film perforated with a special needling needle was prepared by the following method. Using the same special needle-punching method as above, under the same conditions, the above-mentioned base film 2 is perforated from both sides to form 2030 holes (Example 5) and 4060 holes per square inch, respectively. (Example 6).

In addition, the following films were prepared as comparative examples. A film 1 (comparative example 1) that does not perform needle punching on a thermoplastic resin film; a commercially available non-woven fabric (manufactured by Mitsui Chemicals Plastics Co., Ltd.: trade name "No-Tempor", Comparative example 2); using a common hot-melt needle to do point perforation on the thermoplastic resin film at an interval of 10 cm × 20 cm, to obtain a film with a hole diameter of 2 mm (comparative example 3); no needle punching process Film 2 (Comparative Example 4).

(3) Evaluation method

The resulting film was subjected to the following evaluation tests. The results are shown in Table 1.

1. Transparency test

The total light transmittance at 555 nanometers of the films obtained in Examples or Comparative Examples was measured with a spectrophotometer (Hitachi, Ltd. U-2000), and the values were given.

2. Anti-fog test

In the garden of Ichi-gun, Mie Prefecture, a simple tubular greenhouse was built and covered with the film obtained above. It is worth noting that the film obtained by the present invention has the side with a larger surface roughness as the inner side.

The evaluation method is to observe with the naked eye the adhesion of water droplets inside the spread film over a period of time. The evaluation criteria are as follows.

◎ There is no water drop attached to the inner side of the film or the combination of water droplets, and it expands in the form of a film

○ Aggregates between water droplets attached to the surface of the film can be observed, and its area does not reach 2/3 of the film surface but is greater than or equal to 1/2

○× Aggregates between water droplets attached to the surface of the film can be observed, but its area does not reach 1/2 of the surface of the film

△ Aggregates between water droplets attached to the surface of the film can be observed, but not the shape of the film-like part

× Aggregates between water droplets attached to the surface of the film cannot be observed

3. Moisture permeability (prevent water droplet accumulation) test

In the roof-shaped plastic shed with a front width of 16 meters, a beam height of 8 meters, and a depth of 21 meters in the garden of Ichi County, Mie Prefecture, the film covered in the examples or comparative examples is used as a horizontal shade screen in the interior. After a period of time, the state of accumulation of water droplets was visually observed from the top of the film. The evaluation criteria are as follows.

◎ There is no water drop on the upper part of the inner film, or it is dry

○ There is moisture on the upper part of the inner film. But the lining membrane does not relax

○× There is moisture on the upper part of the inner film. The lining membrane is loose. It is not necessary to remove moisture.

△ There is moisture on the upper part of the inner film. The lining membrane is loose. Moisture must be removed.

× There is more moisture in the upper part of the inner film, and the film ruptures due to this weight.

4. Tear strength test

The tear strength in the MD direction of the films obtained in Examples or Comparative Examples was measured in accordance with JIS-K6732, and its value was given as Elmendorf tear strength (g) at a measurement temperature of 0°C.

5. The shape of the resulting micropores

The shape (front view) of the micropores obtained in Examples 1 to 6 is as shown in FIG. 3 , and has a plurality (2 to 4) of puncture-like incisions 4 b around the substantially circular basic hole 4 a. The diameter of the basic hole 4a is about 80 microns, and the diameter of the thorn-shaped cutting damage part 4b is about 85 microns to 110 microns.

The shape of the cross-section of the micropore is schematically shown in FIG. 4, and the thickness (Ha+Hc) of the film thickness Ha (=50 micrometers) plus the protrusion height Hc is 80 micrometers to 90 micrometers.

Regarding the feel of the film, the surface roughness (Ra1) of the film surface on the needle-punched side was large, while the other side (Ra2) was as smooth as the previous film surface. So Ra1<Ra2.

Examples 5 and 6 in which needle punching is performed from both sides of the film have the advantage that the film does not curl.

Table 1

Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Comparative example 1 Comparative example 2 Comparative example 3 Comparative example 4 Matrix membrane Film 1 Film 1 Film 1 Film 1 Film 2 Film 2 Film 1 Non-woven fabric Film 1 Film 2 Perforation 1200 special pinholes (pieces/square inch) Special pinhole 2030 (pieces/square inch) Special pinhole 4060 (pieces/square inch) Special pinhole 6190 (pieces/square inch) Special pinhole 2030 (pieces/square inch) double-sided processing Special pinhole 4060 (pieces/square inch) double-sided processing no pinholes Point perforation 1 / 200cm ² hole diameter 2mm no pinholes 1. Transparency test total light transmittance (%) (555 nm) 90 90 90 90 90 90 90 50 90 90 2. Anti-fog test after 1 month, 3 months, 6 months ◎◎○ ◎◎◎ ◎◎◎ ◎◎◎ ◎◎◎ ◎◎◎ ○○×△ ◎◎◎ ○○×△ ◎◎◎ 3. Moisture permeability test after 1 month, 3 months, 6 months ◎◎◎ ◎◎◎ ◎◎◎ ◎◎◎ ◎◎◎ ◎◎◎ △△× △△△ ◎○○ △△× 4. Eramendorf (g) MD direction of tear strength at 0°C 150 100 90 80 760 615 520 400 300 800

Claims (8)

1. Agricultural film, it is characterized in that, it is the thermoplastic resin film that has a plurality of micropores, and the shape of this micropore is the barbed shape that has thorn part, and the maximum diameter of the basic hole of described micropore is less than or equal to 500mm microns and the minimum diameter is greater than or equal to 10 microns, and the length of the spines is 0.05 microns to 50 microns. 2. The agricultural film according to claim 1, wherein the micropores are obtained by perforating the thermoplastic resin film with a needle having a thorn-like protrusion, and the needle has a small width at its front end. For the cutting edge, the tiny width is 10 microns to 300 microns, and the length of the thorn-like protrusion is 1 micron to 300 microns. 3. The agricultural film as claimed in claim 1 or 2, characterized in that, the relationship between the surface roughness Ra1 on one side of the film and the surface roughness Ra2 on the other side of the film is Ra1<Ra2, and the Ra2 surface is made of plastic or plastic. The inside face that acts as the inside when the tunnel is running. 4. The agricultural film according to claim 1, which has a plurality of micropores obtained by perforating from both sides of the thermoplastic resin film with a needle having a thorn-like protrusion. 5. The agricultural film according to claim 1, which is a thermoplastic resin film having a plurality of microscopic holes perforated by needles, and has microprotrusions perforated by the needles on both sides of the film. 6. The agricultural film according to claim 1 or 2, characterized in that the total light transmittance at 555 nm of the film having a plurality of micropores is greater than or equal to 70%. 7. The agricultural film according to claim 1 or 2, wherein the resin constituting the thermoplastic resin film is vinyl chloride resin or olefin resin. 8. The agricultural film as claimed in claim 1 or 2, characterized in that, said thermoplastic resin film is a resin film made of at least three layers or more than three layers of an outer layer, an intermediate layer, and an inner layer , the resin constituting the outer layer and/or the inner layer contains at least a metallocene polyethylene resin.

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