JP2009268468A - Method for producing sheet against high temperature damage of crop - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a sheet against high temperature damage of crops which has less heat deterioration, durability, and sunlight suppressing effect for a long period, and can prevent high temperature damage of cultivated crops. <P>SOLUTION: This method for producing the sheet against high temperature damage of crops of crops includes forming a cloth-like body by vertically and horizontally crossing a uniaxially drawn yarn in which voids are produced around filler particles by being formed into a tape-like form, a thermoplastic resin spread with inorganic or organic filler particles of weight average particle diameter of 0.01-10 μm, and uniaxially drawing the product. The filler particles comprise hydrotalcite. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for producing a high-temperature damage prevention sheet for crops, and more specifically, high-temperature damage prevention that can prevent high-temperature damage to cultivated crops by suppressing the transmission of heat rays, and has low thermal degradation and durability. The present invention relates to a sheet manufacturing method.

  In the cultivation of crops in the agricultural field, there is a problem that high temperature damage occurs in the crops due to strong sunlight irradiation during the summer, resulting in a decrease in yield or quality. For this reason, in the summer, a sunshade sheet is used to block sunlight.

  As the sun covering sheet used for such a purpose, a sheet colored by adding a pigment or the like to suppress the transmission of sunlight is used (Patent Document 1).

  These are those that suppress the transmission of sunlight by absorbing sunlight with the pigment or powder added to the sheet, but when a pigment or the like that absorbs sunlight is added to the sheet, the sheet is warmed by sunlight. As a result, the thermoplastic resin forming the sheet is greatly deteriorated by heat, and there is a problem that it cannot be used for a long time.

Further, Patent Document 2 discloses a light-shielding net obtained by weaving a vapor-deposited layer, a metal vapor-deposited tape yarn having a polyethylene protective layer laminated thereon, and a monofilament. The net is excellent in light-shielding properties, but this metal vapor-deposited tape yarn does not have a barrier layer formed on its side, so that metal corrosion proceeds due to oxygen, moisture, various disinfectants, etc. There is a problem that pinholes are generated on the surface, and the light shielding property is rapidly deteriorated.
Japanese Patent Laid-Open No. 10-290635 Japanese Utility Model Publication No. 5-33339

  The present invention provides a method for producing a high-temperature failure prevention sheet that has low thermal degradation, has durability, has a solar control effect over a long period of time, and can prevent high-temperature failure of cultivated crops. It is.

  The present invention has been made as a result of intensive studies in order to solve the above-mentioned problems. Specifically, a thermoplastic resin in which inorganic or organic filler particles having a weight average particle diameter of 0.01 to 10 μm are dispersed is provided. After forming into a tape shape, by uniaxially stretching, a uniaxially stretched yarn in which voids are generated around the filler particles intersects vertically and horizontally to form a cloth-like body, and the filler particles are hydrotalcite A method for producing a high temperature damage prevention sheet for crops, a method for producing a high temperature damage prevention sheet for crops, wherein the filler particles are hydrotalcite and aluminum powder, and a cloth-like body The manufacturing method of the high temperature failure prevention sheet | seat of said crop whose porosity represented by following following formula (1) is 5 to 80% is provided.

  Further, the present invention provides a method for producing a high-temperature failure prevention sheet for a crop according to the above, wherein the cloth has an average light reflectance of visible to near infrared rays having a wavelength of 400 to 2000 nm of 30% or more, and the cloth has The present invention provides a method for producing a high-temperature damage prevention sheet for crops, wherein the average light transmittance of visible to near-infrared rays having a wavelength of 400 to 2000 nm is 25% or less.

  The high-temperature damage prevention sheet for crops produced by the production method of the present invention can prevent high-temperature damage of cultivated crops by reflecting heat rays and suppressing transmission, and there is little change in light reflectance over time, It can be used for a long time because there is little thermal deterioration.

(A) which shows an example of the high temperature failure prevention sheet of this invention crop is a top view, (B) is a longitudinal cross-sectional view The longitudinal cross-sectional view which shows the other example of the high temperature failure prevention sheet | seat of this invention crop (A)-(C) is a perspective view showing an example of a uniaxially stretched yarn Longitudinal sectional view showing an example of uniaxially drawn yarn Longitudinal section showing the generation of voids

  As shown in FIG. 1, the crop high-temperature failure prevention sheet 1 of the present invention is constituted by a cloth-like body 3 formed using uniaxially stretched yarns 2 a and 2 b uniaxially stretched from a thermoplastic resin.

  In the present invention, the uniaxially stretched yarn 2 that forms the high-temperature failure prevention sheet 1 broadly means a stretched filament that can form a sheet-like body, and is a filament such as a tape-like body, a string-like body, a monofilament, a multifilament, or the like. The body is included, and these are twisted as necessary.

  The uniaxially stretched yarn 2 may have any structure. For example, as shown in FIG. 3A, a flat yarn formed into a tape shape by slitting a thermoplastic resin film to a predetermined width and uniaxially stretching. Further, as shown in FIG. 3B, a split yarn in which a number of cuts 5 and 5 are formed in a tape-like body can also be used. Furthermore, as shown in FIG. 3C, the tape-like body can be provided with very thin longitudinal ribs 6, and by providing the ribs 6, the reflected light of the sun is scattered to reduce the influence on the environment. Can do.

  In addition, the cross section can be a uniaxially drawn yarn 2 having a round shape, an oval shape, a square shape, a polygonal shape, or other irregular shape. Further, a mixture of different types of resins is extruded into a filament, and a gap between the resins is formed. It is possible to increase the suppleness by using a dumbline that is split and fibrillated. Moreover, one piece can be used alone as a woven yarn, and several pieces can be bundled and used.

  The uniaxially stretched yarn 2 may be a single layer as shown in FIG. 4 (A), or on one or both sides of the base layer 7 as shown in FIGS. 4 (B) and 4 (C). It can be set as the laminated uniaxially stretched yarn 2 in which the joining layer 8 made of a thermoplastic resin having a melting point lower than that of the base layer is formed. Furthermore, the bonding layer 8 may have a seascore structure as shown in FIG. 4D and a side-by-side structure as shown in FIG.

  As the thermoplastic resin constituting the monolayer of the uniaxially stretched yarn 2 or the base layer 7 of the laminate, a resin having a large stretching effect, generally a crystalline resin is used. Specifically, high-density polyethylene, medium density Polyolefins such as polyethylene, polypropylene, ethylene / α-olefin copolymers, olefin polymers such as ethylene / vinyl acetate copolymers, polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyamides such as nylon 6 and nylon 66, acrylonitrile, vinylon Etc. can be used. Of these, olefin polymers such as high-density polyethylene, medium-density polyethylene, linear low-density polyethylene, and polypropylene are desirable from the viewpoint of processability and economy.

  The joining layer 8 joins the uniaxially stretched yarns 2 after the uniaxially stretched yarns 2 are crossed in the vertical and horizontal directions, and has a lower melting point than that of the thermoplastic resin constituting the base layer 7 and is excellent in heat fusion properties. Is used.

  Specifically, olefins such as high-pressure low-density polyethylene, linear low-density polyethylene, high-density polyethylene, polypropylene, ethylene / propylene copolymer, ethylene / α-olefin copolymer, ethylene / vinyl acetate copolymer, etc. Polymers, polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyamides such as nylon 6 and nylon 66 can be used, and the melting point of the base layer is lower than that of the base layer, preferably 20 ° C. or higher. A plastic resin is selected. In particular, olefin polymers such as high-pressure method low-density polyethylene, high-density polyethylene, linear low-density polyethylene, and polypropylene are desirable, and linear low-density polyethylene polymerized using a metallocene catalyst is particularly preferable.

  Furthermore, in the present invention, voids are generated around the filler particles by adding inorganic or organic filler particles to at least the base layer 7 of the thermoplastic resin forming the uniaxially stretched yarn 2 and uniaxially stretching. .

  Filler particles include inorganic particles such as silica, talc, mica and clay, hydroxides such as calcium carbonate, magnesium carbonate and calcium hydroxide, silicates such as sodium silicate and calcium silicate, and titanium oxide. And oxides such as iron oxide, zinc oxide, magnesium oxide, alumina and zeolite, and salts such as aluminum phosphate and barium sulfate. In the organic powder system, phenol resin powder, ebonite powder and the like can be mentioned. You may use these individually or in mixture of 2 or more types.

  The particles have a weight average particle size of 0.01 to 10 μm, preferably 0.05 to 5 μm, more preferably 0.1 to 3.0 μm. When the weight average particle size is less than 0.01 μm, the generation of voids during stretching is small and the light reflectance is reduced, and when it exceeds 10 μm, the voids are excessive and the strength of the uniaxially drawn yarn 2 is reduced To do. The amount is usually 0.1 to 50% by weight, preferably 0.5 to 30% by weight.

  The thermoplastic synthetic resin that forms the uniaxially stretched yarn 2 can be blended with various additives as necessary. Examples thereof include phenols, organic phosphites, phosphines and other organic phosphorus, thioethers, and the like. Antioxidants; Light stabilizers such as hindered amines; Ultraviolet absorbers such as benzophenones, benzotriazoles, and benzoates; Antistatic agents; Dispersants such as bisamides, waxes, and organometallic salts; Alkaline earth metals Chlorine scavengers such as carboxylates of salts; Lubricants such as amides, waxes, organometallic salts, and esters; Metal deactivators such as hydrazines and amine acids; Bromine-containing organics, phosphoric acids, etc. Inorganic and organic antibacterial agents such as metal pigments, organic pigments, inorganic pigments, and metal ions can be added.

  These additives are appropriately combined and blended in any step of manufacturing the material composition of the base layer 7 and the bonding layer 8. The blending of the additive may be prepared by mixing at a predetermined ratio using a kneading device such as a conventional known twin screw extruder, Banbury mixer, kneader, mixing roll, and melt-kneading the mixture. A so-called master batch having a high concentration may be prepared and used after being diluted.

  When the laminated uniaxially drawn yarn 2 is used, as a means for forming a laminated film that becomes a molding material of a laminated flat yarn or a laminated split yarn, a film that becomes the base layer 7 and a film that becomes the bonding layer 8 are formed in advance. Means for forming a multilayer using a dry laminating method or a thermal laminating method, a method of coating a thermoplastic resin to be the bonding layer 8 on the surface of the film to be the base layer 7, a bonding layer 8 to the film to be the base layer 7 formed in advance. Any known means such as extrusion laminating or extrusion molding as a laminated film by multilayer coextrusion may be appropriately selected and used. Ease of molding and cost, and adhesion between each layer of the product In this respect, a method of obtaining a laminated body of the base layer 7 and the bonding layer 8 in one step by a multilayer coextrusion method is desirable. The seascore structure or side-by-side structure is generally based on a coextrusion method.

  The obtained thermoplastic synthetic resin film remains in the form of a film or is formed into a tape and then subjected to a uniaxial stretching process. By stretching the thermoplastic synthetic resin in which the filler particles are dispersed, as shown in FIG. 5, voids, that is, voids 11 can be generated around the filler particles 10, mainly before and after the stretching direction. By generating innumerable voids 11 in the uniaxially stretched yarn 2, it is possible to reflect and disperse the sunlight that is irradiated, and the transmission of direct light is suppressed.

  As a means for stretching to make the uniaxially stretched yarn 2, a film that becomes the base layer 7 may be stretched in a uniaxial direction, and then a thermoplastic resin that becomes the bonding layer 8 may be laminated and slit into a tape shape, or It can also be obtained by stretching in a uniaxial direction before or after slitting the laminated film in which the base layer 7 and the bonding layer 8 are laminated. Stretching is desirably performed at a low temperature as much as possible, and the stretching ratio is usually about 3 to 10 times.

  The thickness of the uniaxially stretched yarn 2 is not limited in any way and can be arbitrarily set according to the purpose, but is generally 50 to 10,000 decitex, preferably 100 to 5000 decitex. In the case of a tape, the yarn width is 0.3 to 200 mm, preferably 0.5 to 100 mm, and the yarn thickness is 5 to 500 μm.

  When the layer structure of the elongated filament 2 is a three-layer structure, generally, the thickness composition ratio is set to be bonding layer: base layer: bonding layer = 1: 98: 1 to 25:50:25.

  As shown in FIGS. 1 (A) and 1 (B), the drawn filament 2 thus obtained can be woven into a plain weave to form a cloth-like body 3. In addition, it can be made into a cloth-like body 3 by weaving in a twill weave, a twill weave, a knit weave, a double weave, a double weave, a knit weave, etc. It is also possible to make a cloth-like body. As a loom for weaving, a known loom such as a circular loom, a slewer loom, a water jet loom can be used. Further, as shown in FIG. 2, a plurality of elongated filaments 2b are arranged in parallel, and another elongated filament 2a is arranged in parallel in the direction intersecting with the elongated filament 2b, and the intersection is thermally bonded. It can be set as the cloth-like body 3 which consists of the cross-bonded cloth (soft).

  The cloth-like body 3 desirably forms a hole through which air passes, and is woven so that the porosity of the yarn shown below is 5 to 95%, preferably 10 to 85%. If it is less than 5%, the heated air stays inside the covered sheet, and high temperature damage is likely to occur in the crop, and if it exceeds 95%, the heat ray blocking effect is reduced and high temperature damage is caused. The effect of preventing is reduced.

  In the present invention, it is desirable that the cloth body has an average light reflectance of visible to near-infrared having a wavelength of 400 to 2000 nm of 30% or more, preferably 40% or more, and further visible for a wavelength of 400 to 2000 nm. It is desirable that the average light transmittance of near infrared rays is 25% or less. These average light reflectance and average light transmittance are preferably maintained even after one year or more of use.

  As a method for controlling the light transmittance or the average light transmittance, the amount of inorganic powder added to the base layer 7 or the bonding layer 8 constituting the uniaxially stretched yarn 2, the degree of stretching of the uniaxially stretched yarn 2, that is, the void It can be adjusted by the amount generated, the fineness of the uniaxially stretched yarn 2, the number of warp yarns to be driven, and the like.

Example 1
1. As a flat yarn base material, 50% by weight of high-density polyethylene (density 0.956 g / cm ³ , melting point 134 ° C.) and 50% by weight of hydrotalcite (DHT-4A, Kyowa Kogyo Co., Ltd., weight average diameter 0.4 μm) A resin composition obtained by adding 1.5 parts by weight of aluminum powder to 100 parts by weight of a resin composition, and using ^three layers of low density polyethylene (density 0.922 g / cm ³ , melting point 113 ° C.) as a bonding layer. After the laminated film was formed by the inflation method, it was slit to a predetermined width, stretched 6.0 times at 65 ° C. using a hot plate, and then subjected to a relaxation treatment of 8% in a hot air oven at 105 ° C., 670 dt, A 1.0 mm wide flat yarn was formed.

2. Weaving Using the above flat yarns for warp and weft yarns, weaving the warp and weft density to 9 / 25mm each with a slewer loom, and then fusing the intersections of the yarns with a 120 ° C hot roll, A woven fabric having a porosity of 51% was obtained.

Example 2
In Example 1, the same experiment as in Example 1 was performed except that the addition of aluminum powder was omitted.

Comparative Example 1
In Example 1, instead of adding hydrotalcite and aluminum powder, 10% by weight of a silver pigment (manufactured by Tokyo Ink Co., Ltd.) was added to the substrate, and the stretching operation was performed at 110 ° C. A woven fabric was obtained. When the flat yarn was cut with a cutter knife and the cut end was observed with a magnifying glass, no void was found.

Comparative Example 2
Aluminum is vapor-deposited on a base material made of high-density polyethylene (density 0.956 g / cm ³ , melting point 134 ° C.), tape yarn on which a protective layer of polyethylene is laminated, and monofilament made of polyethylene are knitted to create a porosity of 51% A woven fabric was obtained.

  About the woven fabric obtained by the above method, the light reflectance of a wavelength of 400 to 2000 nm and the outdoor ground are covered in a tunnel shape, the change in the ground temperature is measured, and the maximum temperature difference with respect to the uncovered state in one day Was measured. The results are shown in Table 1. In addition, the light reflectance and strength retention were measured for a woven fabric coated for one year. The results are shown in Tables 2-4.

  The high temperature failure prevention sheet of the present invention crop can be used as a tunnel cover, a house-type cover, or a curtain in a house as a cover for crop cultivation.

1. 1. High temperature damage prevention sheet for crops Uniaxially drawn yarn 4. Cloth-like body Break 6. Rib 7. Base layer 8. Bonding layer 10. Filler particles 11. void

Claims (5)

  A uniaxially stretched yarn in which voids are generated around the filler particles by making a thermoplastic resin in which inorganic or organic filler particles having a weight average particle diameter of 0.01 to 10 μm are dispersed into a tape shape and then uniaxially stretching. A method for producing a high-temperature damage prevention sheet for crops, characterized in that a cloth-like body is formed by vertically intersecting and the filler particles are hydrotalcite.   A uniaxially stretched yarn in which voids are generated around the filler particles by making a thermoplastic resin in which inorganic or organic filler particles having a weight average particle diameter of 0.01 to 10 μm are dispersed into a tape shape and then uniaxially stretching. A method for producing a high-temperature damage prevention sheet for crops, characterized in that a cloth-like body is formed by intersecting vertically and horizontally, and the filler particles are hydrotalcite and aluminum powder. The method for producing a high-temperature damage prevention sheet for crops according to claim 1 or 2, wherein the porosity represented by the following formula (1) of the cloth-like body is 5 to 80%.

The cloth-like body has an average light reflectance of visible or near infrared rays having a wavelength of 400 to 2000 nm of 30%.
It is the above, The manufacturing method of the high temperature failure prevention sheet of the crops in any one of Claim 1 to 3.   The method for producing a high temperature damage prevention sheet for crops according to any one of claims 1 to 3, wherein the cloth has an average light transmittance of visible to near infrared rays having a wavelength of 400 to 2000 nm of 25% or less.

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