JP2008148648A - Photosynthesis-promoting film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photosynthesis-promoting film having an extremely simple and ready structure, capable of extremely efficiently and effectively diffusing visible light absorbed into chlorophyll dye for promoting photosynthesis of plants and diffusely reflecting the chlorophyll dye and having high illuminance. <P>SOLUTION: The photosynthesis-promoting film is a white foam resin film having a closed cell structure and promotes photosynthesis of plants by high diffusion and diffused reflection to visible light. The foam resin film may be composed of polypropylene, polyethylene terephthalate, polyethylene or polystyrene. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a photosynthesis promotion film.

  In general, reflective sheets for agriculture are laid around the roots of grapes and fruit trees for growing crops, for example, in the cultivation of fruit trees such as apples and mandarin oranges, and irradiate all fruits with light. It is used for the purpose of increasing the color of fruits. As such a reflection sheet, an agricultural soil covering sheet is known (see, for example, Patent Document 1). This covering sheet is a laminated sheet composed of a cloth-like fiber assembly layer, a specular reflective foil-like metal layer such as an aluminum foil, and a synthetic resin film layer. In addition, in order to enhance the reflectivity of the sheet, a reflective sheet in which a metal vapor deposition layer is formed is frequently used.

However, the conventional reflection sheet having a light reflection layer such as a metal deposition layer such as aluminum or a metal foil layer as described above has a strong light reflection function, but only light in a specific direction with respect to incident light is reflected. Tend to. Furthermore, heat burns of fruits and the like due to heat reflection of the reflection sheet are a problem. Agricultural multi-sheets with high surface whiteness have also been proposed (see, for example, Patent Document 2). The agricultural multi-sheet is formed by integrating bleached defatted cellulose fibers, and actually has a high light transmittance to the sheet, and there is a concern that the degree of light irradiation by reflection is weak. Yes.
Utility Model Registration No. 3078702 JP 2005-198617 A

  The present invention has been made in view of the above points, and an object of the present invention is to provide a photosynthesis promotion film capable of diffusely reflecting diffusely and effectively visible light absorbed by a chlorophyll pigment that promotes photosynthesis of plants. And

  That is, the invention of claim 1 relates to a photosynthesis promotion film characterized in that it is a white foamed resin film having a closed cell structure and promotes photosynthesis of plants by high diffuse diffuse reflection with respect to visible light.

  The invention according to claim 2 relates to the photosynthesis promoting film according to claim 1, wherein the foamed resin film is made of polypropylene, polyethylene terephthalate, polyethylene or polystyrene.

  Invention of Claim 3 concerns on the photosynthesis promotion film of Claim 1 or 2 whose visible light spectral reflectance is 60% or more.

  According to the photosynthesis promoting film of the invention of claim 1, the white foamed resin film having a closed cell structure, which promotes photosynthesis of plants by high diffuse diffuse reflection with respect to visible light. The light is effectively reflected and the illuminance of the reflected light is high, so that the growth of the plant is promoted. In particular, when laid and used in orchards, house cultivation, etc., the coloring degree and sugar content of fruits can be remarkably improved.

  According to the invention of claim 2, since the foamed resin film is made of polypropylene, polyethylene terephthalate, polyethylene or polystyrene in claim 1, the film has excellent moldability and workability.

  According to the invention of claim 3, since the visible light spectral reflectance is 60% or more in claim 1 or 2, the photosynthesis of the plant can be promoted more reliably and effectively.

  The present invention will be described below with reference to the accompanying drawings. FIG. 1 is a schematic cross-sectional view of a photosynthesis promoting film according to an embodiment of the present invention.

  As shown in FIG. 1, a photosynthesis promoting film 10 according to the present invention is a white foamed resin film 11 having a closed cell structure, which promotes plant photosynthesis by high diffuse diffuse reflection with respect to visible light. is there.

  The raw material resin constituting the foamed resin film 11 is not particularly limited, and specifically, polyvinyl chloride resin, nylon, vinylidene chloride resin, polyethylene, polypropylene, polyvinyl alcohol, polyetherimide, polyimide, polyurethane, polyolefin, polyamide, Polyester, methacrylic resin, phenolic resin, melamine resin, epoxy resin, urea resin, unsaturated polyester resin, silicone resin, synthetic plastic such as fluororesin, synthetic rubber such as polyisoprene and butadiene, acrylic resin such as polymethylmethacrylate, polystyrene , Styrene-acrylonitrile resins such as styrene-acrylonitrile copolymers, hydrogen bondable resins such as ethylene-vinyl alcohol copolymers, polycarbonate resins, polyketone resins, etc. And the like.

  Among these, the foamed resin film 11 is preferably made of polypropylene, polyethylene terephthalate, polyethylene, or polystyrene, which is a thermoplastic resin, from the viewpoints of cost, moldability, ease of forming a closed cell structure, and the like. For example, ethylene-α-olefin copolymers such as low density polyethylene, high density polyethylene, linear low density polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-butene 1 copolymer, ethylene-hexene copolymer Random copolymers, block copolymers and the like may be used alone or in combination of two or more.

  Polyethylene phthalate is a resin mainly composed of ethylene glycol and terephthalic acid polyester. As copolymer monomers, glycol components diethylene glycol, 1,4-tetramethylene glycol, 1,4-cyclohexanedimethanol, heptane Examples thereof include resins mainly composed of a polymer obtained by partially replacing methylene glycol with isophthalic acid, dicarboxylic acid, adipic acid or the like as a monomer. In addition, as polystyrene, general polystyrene or thermal shock-resistant polystyrene and a mixture thereof can be used.

  The foamed resin film 11 has a closed cell structure and exhibits white. The closed cell structure in the present invention refers to a state in which individual bubbles exist independently in a resin film as a matrix. As shown in FIG. 1, the foamed resin film not only has irregularities on the film surface but also has closed cells 12 inside, and was not reflected on the surface as well as light reflection on the film surface. When light enters the inside of the film, the light is diffused and diffusely reflected by the interface between the closed cells inside the foamed resin film and the resin film, so that the light incident from all directions can be diffused and diffusely reflected effectively. Therefore, it is presumed that the light absorption rate and transmittance are reduced as compared with a foamed resin film having only open cells, and that much light is diffused and diffusely reflected.

  Next, the manufacturing method of the foamed resin film 11 which is the photosynthesis promotion film 10 of this invention is demonstrated. As a method of forming bubbles inside the resin film, for example, a method of forming bubbles inside the film by injecting a bubble forming agent or carbon dioxide gas into the film, and an organic or inorganic additive is contained in the raw resin For example, a method of dissolving the additive by solvent extraction to form bubbles in the film after melt extrusion is used. In addition, the obtained foamed resin film may be stretched or unstretched.

  Furthermore, as a method for producing a foamed resin film, it is easy to control the ratio of bubbles in the foamed resin film, and from the viewpoint of easy formation of closed cells, by containing a bubble forming agent inside the resin film, by stretching, A method of producing the foamed resin film by forming fine bubbles inside the film is mentioned. Specifically, the raw material resin and the bubble forming agent constituting the foamed resin film are kneaded in an extruder, and the heated and melted raw material resin and the bubble forming agent are cooled from a horizontally long die connected to the extruder. The resin film is formed by being extruded onto a roll. And by the well-known method, the said resin film is extended | stretched to a uniaxial direction or a biaxial direction, peeling and a cavity arise between a bubble formation agent and a resin component, and an independent bubble is formed. The stretching method is not particularly limited, but a biaxial stretching method in which stretching is performed in the machine direction (also referred to as MD) and the width direction (also referred to as TD) perpendicular thereto is preferable because the film strength and elongation are not directional.

  As described above, in the case of forming a resin film by containing a cell forming agent in the raw material resin, as the cell forming agent, calcium carbonate, magnesium carbonate, zinc carbonate, titanium oxide, zinc oxide, barium sulfate, zinc sulfide, Basic lead carbonate, titanium, silica, alumina, mica, talc, kaolin, and the like are appropriately used singly or in combination of two or more. The foamed resin film is added with a heat stabilizer, an oxidation-resistant stabilizer, an ultraviolet absorber, an organic lubricant, a filler, a pigment, and various additives to such an extent that the effects of the present invention are not impaired. Also good.

  The photosynthesis promotion film of the present invention formed as described above promotes plant photosynthesis by high diffuse diffuse reflection with respect to visible light. In photosynthesis, chlorophyll pigments that absorb light are contained in the chloroplasts of plants. Photosynthesis is promoted by the absorption of light by these chlorophyll pigments. It is said that there is a correlation between the visible light absorbed by the chlorophyll dye and the speed of photosynthesis. Specifically, blue-violet visible light having a wavelength of about 400 to 500 nm and red visible light having a wavelength of about 580 to 800 nm are converted into chlorophyll dye. Is absorbed to promote photosynthesis.

  The visible light spectral reflectance of the photosynthesis promoting film is preferably 60% or more. When the visible light spectral reflectance is 60% or more, it is possible to diffuse and reflect visible light more reliably and effectively to promote photosynthesis and plant growth. This visible light spectral reflectance is measured by using a spectrophotometer (“UV-3101PC” manufactured by Shimadzu Corporation) with a 400-800 nm light incident on the film surface from the sample surface and the average method over the entire wavelength range. This is a value obtained by measurement.

  Furthermore, the backing layer may be laminated | stacked on the photosynthesis promotion film of this invention. The backing layer may be laminated on one side or both sides of the photosynthetic film without departing from the spirit of the present invention, or a plurality of layers may be laminated as the backing layer. By forming the backing layer, functions such as heat insulation, durability and workability can be improved or imparted to the photosynthesis promotion film. As the backing layer, mainly for the purpose of improving heat insulation, porous materials made of synthetic resins such as polyurethane, polyolefin, polyvinyl chloride and polystyrene, natural organic polymer compound fibers such as cellulose and rayon, and high density Nonwoven fabric manufactured by known methods such as the Metroblow method and Spunbond method using polyolefin fibers such as polyethylene and polypropylene, polyurethane fibers, acrylic fibers, etc., and further embossed by making cellulose fibers Examples thereof include a nonwoven fabric that is self-adhered to form a sheet by applying heat and pressure with a roll.

  In order to improve durability, strength, or workability, the backing layer is made of a polyolefin, such as polypropylene or polyethylene, a film of synthetic resin such as polyurethane, polyvinyl chloride, nylon, or polyamide, a sheet, or the synthetic resin. It may be formed of a fibrous material or a woven or non-woven fabric of natural fibers such as cotton or hemp. Examples of the synthetic resin include polypropylene, high density polyethylene, low density polyethylene, polyolefins such as polyethylene, polyurethane, polyvinyl chloride, nylon, and polyamide. Synthetic resin woven fabrics are conventionally known and manufactured by a known method, specifically, in order to increase the tear strength, in particular, a flat yarn, a split yarn or the like is prepared from a synthetic resin sheet or film, A woven fabric is obtained by a conventionally known method such as plain weave, twill weave, and Russell weave.

  As described above, by using the photosynthesis promoting film of the present invention, for example, when laying the film in orchards, house cultivation, etc., the visible light directly reaching from the sun and the visible light reflected from the photosynthesis promoting film The chlorophyll pigment contained in chloroplasts of leaves can effectively and efficiently promote photosynthesis. By promoting photosynthesis, the growth of fruits and trees is improved, fruits with excellent coloring and high sugar content can be obtained. It can also be used in the same manner for agricultural products such as vegetables and horticultural plants.

Examples of the photosynthesis promoting film in the present invention will be described.
[Example 1]
A polypropylene resin as a raw material resin and calcium carbonate as a bubble forming agent were kneaded in an extruder, and extruded from a horizontally long die of a T die connected to the extruder onto a cooling roll to form a film. The extrusion temperature at this time was about 210 to 230 ° C. Next, the film was stretched in the machine direction and the width direction by a biaxial stretching method to obtain the photosynthesis promoting film of Example 1. The stretching temperature in the tenter was about 160 to 180 ° C., and the stretching ratio was about 40 to 45 times.

[Example 2]
Kneaded in an extruder using polyethylene resin as a raw material resin and azodicarbonamide (a foaming agent “Sermark MB3013” manufactured by Sankyo Kasei Co., Ltd.) as a bubble forming agent, and extruded by a gas generated during T-die extrusion by a known method. The foamed resin film was molded by foaming to obtain the photosynthesis promoting film of Example 2. The extrusion temperature at this time was about 140 to 160 ° C. In Example 2, unlike Example 1, an unstretched film was used.

[Comparative Example 1]
As Comparative Example 1, an agricultural aluminum vapor-deposited sheet ("Multimirror F" manufactured by Reiko Co., Ltd.) made of an aluminum vapor-deposited biaxially oriented polypropylene film and a high-density polyethylene film was used.
[Comparative Example 2]
As Comparative Example 2, a nonwoven fabric made of polyethylene fibers (manufactured by DuPont, “Tyvek 400WP”) was used.

[Comparative Example 3]
As Comparative Example 3, a non-woven fabric made of cellulose short fibers ("TCF5025" manufactured by Futamura Chemical Co., Ltd.) was used.
[Comparative Example 4]
As Comparative Example 4, a sponge-like polyurethane sheet obtained by mixing 4,4-diphenylmethane diisocyanate as a curing agent with a modified polyol (“Nisshin Resin Co., Ltd.“ Foamed Urethane Soft N ”) was used.

[Comparative Example 5]
As Comparative Example 5, an unstretched polypropylene film (“FLS-W” manufactured by Phthamura Chemical Co., Ltd.) containing a white pigment and a weathering agent was used.
[Comparative Example 6]
As Comparative Example 6, a matte biaxially stretched polypropylene film (“FOR-M” manufactured by Phutamura Chemical Co., Ltd.) was used.

  For each of the examples and comparative examples, the visible light spectral reflectance (%), the film color, and the like were evaluated in the apple orchard ("San Fuji") orchard. Moreover, the light reflectance (%) of Example 1 and Comparative Example 1, the reflection distribution measurement using a goniophotometer, and the illuminance (lux) of Example 1, Comparative Examples 1 and 2 were measured. The properties, materials, presence / absence of foam (or bubbles), color and appearance of Examples 1 and 2 and Comparative Examples 1 to 6 are shown in Table 1 below.

[Visible light spectral reflectance (%)]
For Examples 1 and 2 and Comparative Examples 1 to 6, the visible light spectral reflectance (%) was measured. Light of 400 to 800 nm was incident on the film surface from the sample surface, and measurement was performed using a spectrophotometer by the all-wavelength average method. As the spectrophotometer, “UV-3101PC” manufactured by Shimadzu Corporation was used. Table 2 below shows the values of visible light spectral reflectance (%). In Table 2, the maximum value (%) and the minimum value (%) are the maximum value and the minimum value of the visible light spectral reflectance.

[Evaluation of coloring and sugar content of apples]
The coloration and sugar content of apples were evaluated from October 21 to November 21, 2006 in an orchard of the apple “San Fuji” (variety: Fuji (non-bag) hatched) in Hirosaki, Aomori Prefecture. For one month, the films of Examples 1 and 2 and Comparative Examples 1 to 6 were laid at the base of the fruit tree. The size of each film was 2 × 5 m. The method of laying each film is 2 per apple tree so that each film is laid on both sides of the apple tree so that the longitudinal direction of the film is in the north-south direction. Sheets of film were juxtaposed. The degree of coloration of the apples was evaluated by arbitrarily collecting five apples from the upper, middle and lower sides of the apple tree on which the films of the examples and comparative examples were laid, and the average value was obtained. Furthermore, regarding the sugar content of apples, the sugar content was examined for each of the upper, middle and lower parts of each apple, and the average value was determined. Even when no film was laid, the evaluation was performed in the same manner as described above.

・ Coloring degree of apple: Evaluated by coloring area of apple peel. The area of the red portion was visually observed by five people, and was evaluated in 10 stages from 0 to 10, and the average value was obtained. “0” indicates no coloration, “5” indicates that the half of the skin is colored, and “10” indicates that the entire skin is colored. FIG. 2 shows the measurement results of the sugar content and the increase value after one month from the start of measurement. In the figure, the apples of Comparative Example 1 where the apples were collected at the lower stage after one month of measurement (see the portion marked with “*” in the figure) were found to have burned due to heat reflection on some skins. Moreover, the blank in a figure is an evaluation result in the case where the film is not laid.
-Sugar content (degree) of apple: Measured with a liquid concentration meter "PAL-1" manufactured by Atago Co., Ltd. Table 3 below shows the sugar content (degree) one month after the start of measurement, and Table 4 shows the increase value (degree). In addition, the blank in the following table | surface is an evaluation result in the case where the film is not laid.

[Light reflectance (%)]
For Example 1 and Comparative Example 1, the spectral reflectance (%) was measured twice using a spectrophotometer (“UV-3101PC” manufactured by Shimadzu Corporation). The spectrum of the measurement result of the light reflectance (%) for each wavelength is shown in FIG. 3 for Example 1 and in FIG. 4 for Comparative Example 1. 3 and 4, the spectrum of Example 1 showed an extremely high reflectivity with stability at all wavelengths with the vicinity of the visible light region of 400 to 800 nm as the apex.

[Reflection distribution measurement]
About the film of Example 1 and the comparative example 1, the reflectance (%) with respect to an incident angle (-90-90 degree | times) was measured using the goniophotometer. As a variable angle photometer, “GC 5000L” manufactured by Nippon Denshoku Industries Co., Ltd. was used. The reflection distribution diagram of Example 1 is shown in FIG. 5, and the reflection distribution diagram of Comparative Example 1 is shown in FIG. In the figure, the area under the broken line represents the amount of light reflected, and the larger the area, the greater the amount of diffuse diffuse reflection at all angles. Comparing the distribution charts of FIGS. 5 and 6, it is clear that Example 1 reflects light at any incident angle and has a larger amount of light than Comparative Example 1.

[Illuminance (lux)]
When the films of Example 1 and Comparative Examples 1 and 2 were laid, and the ground surface where nothing was laid, the illuminance was measured with respect to the distance (cm) from the laying surface or the ground surface. "LX-1188"). The illuminance measurement was performed around 13:00 on November 21, 2006, outdoors in Aichi Prefecture. The result is shown in FIG. In addition, the blank in a figure is a measurement result in case the film is not laid. The illuminance of Example 1 showed very high illuminance at a distance of 50 to 350 cm from the laying surface, whereas Comparative Examples 1 and 2 showed weak illuminance.

  From the above results, the photosynthetic promotion films of Examples 1 and 2 had high visible light spectral reflectivity, as well as extremely diffuse diffuse reflection and illuminance. In the evaluation results of the degree of coloration and sugar content of apples, it was confirmed that the coloration progressed uniformly regardless of the position where apples were collected and the position where apples were measured, and the sugar content rose to around 17 degrees. . Therefore, it was found that the photosynthetic promotion films of the Examples had a great effect on the photosynthesis of plants and had an excellent effect on promoting photosynthesis. On the other hand, as in Comparative Example 2 and Comparative Example 3, even if only the visible light spectral reflectance is relatively high, if the illuminance is low, it is difficult to affect the growth of fruits and plants. The result was also confirmed. In addition, in the aluminum vapor deposition film of the comparative example 1, reflection was non-uniform | heterogenous and in the coloring degree evaluation of an apple, the burn by partial heat reflection was confirmed by the apple. Further, in Comparative Examples 4, 5, and 6, many bubbles communicating with the inside of the film were formed, or no bubbles were formed inside the film, so the visible light spectral reflectance was low, and light was reflected from the film surface. However, since the ratio of absorption and transmission was large, the effect of promoting the photosynthesis of plants could not be obtained.

It is a schematic sectional drawing of the photosynthesis acceleration | stimulation film which concerns on one Example of this invention. It is a figure which shows the coloring degree of the photosynthesis acceleration | stimulation film of Examples 1, 2 and Comparative Examples 1 thru | or 6. It is a figure which shows the spectrum of the measurement result of the light reflectivity (%) of Example 1. FIG. It is a figure which shows the spectrum of the measurement result of the light reflectivity (%) of the comparative example 1. FIG. 6 is a reflection distribution diagram in which reflectance (%) with respect to an incident angle is measured using the goniophotometer of Example 1. FIG. It is the reflection distribution figure which measured the reflectance (%) with respect to an incident angle using the variable angle photometer of the comparative example 1. It is a figure which shows the measurement result of the illumination intensity with respect to the distance (cm) from Example 1, the comparative examples 1 and 2, and the laying surface of a blank, or the ground surface.

Explanation of symbols

10 Photosynthesis promotion film 11 Foamed resin film 12 Closed cell

Claims (3)

  A white foamed resin film having a closed cell structure, which promotes photosynthesis of plants by high diffuse diffuse reflection with respect to visible light.   The photosynthesis promotion film according to claim 1, wherein the foamed resin film is made of polypropylene, polyethylene terephthalate, polyethylene, or polystyrene.   The photosynthesis promotion film according to claim 1 or 2, wherein the visible light spectral reflectance is 60% or more.

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