JPS602360A - Agricultural coating material - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to agricultural covering materials, and more particularly to agricultural covering materials excellent in heat retention, dehumidification, and dew condensation prevention properties.

The main purposes of facility cultivation are to ensure year-round crop production, stabilization, high-yield quality products, and planned production. In other words, it is an attempt to increase productivity in a period when crops are produced in a period when it is impossible to produce under the conditions of the bushland, or in a period when productivity is low. It is said that in 1952, plastic film appeared as a substitute for hotbed paper in facility cultivation in Japan and began to be used for raising seedlings.

After that, various agricultural films were developed for use in greenhouses, tunnels, mulching, and even for greenhouse tension, and with the spread of these films, greenhouse horticulture in Japan has made rapid progress.

Conventionally, agricultural films used in the field of greenhouse horticulture include films made of synthetic resins such as polyethylene, polyvinyl chloride, ethylene-vinyl acetate copolymer, and polyester, but they have some problems. Oh dear,
It cannot be said that it is truly satisfying.

First of all, the first problem is that the heat retention is insufficient.

In other words, the main purpose of covering materials such as agricultural films is to allow enough sunlight to pass through during the day, raise the temperature inside the canopy and activate photosynthesis, and also to allow it to penetrate underground or into the crop during the day. The purpose is to prevent the dissipation of stored heat, that is, to keep warm.

<Determined by infrared absorption in the long wavelength range centered on 6 to 17μ. In other words, crops and the ground that are heated by sunlight during the day cool down by emitting infrared rays centered around 6 to 17 microns, so-called long waves, but if they are covered with a coating material that absorbs this infrared ray well, they can cool down at night. can be suppressed. However, such infrared absorption ability is determined by the molecular structure of the synthetic resin itself, but films made of synthetic resins such as polyethylene, ethylene-vinyl acetate copolymer, polyvinyl chloride, and polyester, which are conventionally used as agricultural materials, are This infrared absorption ability is low and heat retention is lacking.

In particular, films made of polyethylene or ethylene-vinyl acetate copolymers lack heat retention, and in some cases even lower the temperature of uncoated exposed areas.

Furthermore, the second problem is the lack of hygroscopicity and moisture permeability, that is, the lack of dehumidification and dew condensation prevention properties, and this is precisely the problem that is important in modern greenhouse horticulture, where energy conservation is essential. be.

In other words, under airtight coverings such as greenhouses or tunnels (particularly as energy conservation measures have been promoted recently, with multiple coverings to improve airtightness and thorough insulation, crops can grow thickly). If so, the inside of the facility tends to become extremely humid, and this humid environment not only promotes the occurrence of disease in crops, but also blocks sunlight from condensation on the surface of the covering material.

However, films made of synthetic resins such as polyethylene, polyvinyl chloride, ethylene-vinyl acetate copolymer, and polyester, which have been widely used in conventional greenhouses, tunnels, and greenhouse interiors, have hygroscopicity, moisture permeability, that is, dehumidification, and dew condensation. Since there is no preventive property, the above problems cannot be solved.

Recently, non-woven fabrics made of polyester, polyolefin, etc. have been used as house tension tens as a way to improve this problem, but this simply utilizes the voids in the non-woven fabric, and the material itself has moisture absorption and moisture permeability. Not only is it insufficiently effective, but its fatal drawbacks are that it has poorer heat retention than polyethylene film and is opaque, significantly blocking sunlight, which is essential for crop growth.

The inventors of the present invention have worked diligently to solve the above-mentioned drawbacks of existing agricultural covering materials, and as a result have completed the present invention. ,
An object of the present invention is to provide an agricultural covering material having dehumidification and dew condensation prevention properties.

Further objects and effects of the present invention will become apparent from the following description.

The above purpose is to (a) stretch a hydrophobic synthetic resin film laminate or (c) stretch a polyvinyl alcohol film;
The hydrophobic film in the present invention is achieved by an agricultural a-glue made by bonding and integrating at least one type of reticulated nonwoven fabric, which is obtained by splitting, heat-treated and widened, and at least one type of reticular nonwoven fabric laminated and adhered to the warp and warp. It is a film made of synthetic resin with excellent water resistance, such as films made of evaporated polyester, acrylic resin, polyvinyl chloride, ethylene-vinyl acetate copolymer, polyolefin, etc. However, films made of polyester or acrylic resin are particularly suitable from the viewpoint of weather resistance, heat resistance, and transparency. Further, the film may be produced by any known method, and may be a simply formed unstretched film or a uniaxially or biaxially stretched film. Furthermore, the coating material for agricultural vegetables of the present invention is preferably from 10 to 200 μm, more preferably from 20 to 100 μm, although there is no particular limitation on the thickness of the material. This is a product made by bonding and integrating the above-mentioned hydrophobic film and polyvinyl alcohol (hereinafter referred to as PvA, abbreviated as i>f), which is a special material used as a raw material.

That is, the special material characterized by PVA used in the present invention is a warp WJ fi layer of a PVA-based axially stretched and heat-treated film, or a funnel-shaped body obtained by stretching, splitting, and heat-treated widening a PVA-based film. It is a cotton-like non-woven fabric made by laminating and bonding .

What is the laminate of the present invention in which PVA-based axially stretched, heat-treated films are laminated in the warp and warp direction with the stretching axis shifted? PVA with an average degree of polymerization of 1000 or more and a saponification K of 985X or more is suitable.
At least 5 ft at 180°C or higher
A PVA-based axially stretched, heat-treated film obtained by highly stretching 5 times or more, specifically 6 to &5 times, and then heat-treating at 200°C or more, is laminated along the warp and warp, preferably orthogonally a[
There are many things that happen.

The PVA-based film used in the present invention is preferably a film made of 100% of at least one type of PVA with a degree of polymerization of 1000 or more and a degree of saponification of 98% or more, and a film made of 100% of at least one kind of PVA with a degree of polymerization of 1000 or more and a degree of saponification of 98% or more. A copolymer containing other monomers or polymers in a proportion of 30 mol% or less,
It means a film made of modified PVA such as a polymer mixture. Furthermore, plasticizers such as glycerin and polyalkylene ether, ultraviolet absorbers, etc. may be added as appropriate.

Such a PVA-based film may be produced by any known method, such as by stretching a GpvA-based film that can be easily obtained from an aqueous solution containing PVA as a main component (by casting, wet method, extrusion, etc.). For this purpose, a heating roller or a heating chamber may be used to utilize the speed difference between two sets of vinyl rolls, and multi-stage stretching may be performed if necessary.

Further, the heat treatment may be performed by any known method, and generally a heated cylinder or chamber is used, but the latter method using 7 cylinders is preferable to further enhance the heat treatment effect. In this case, the average polymerization of PVA degree is 1
000 or more and the saponification degree is 98% or more.
It is possible to obtain a warp/warp laminate of A-based axially stretched, heat-treated film with excellent practical strength and dimensional stability. In addition, it is preferable that the stretching temperature/degree is 180°C or higher in terms of stretchability of the pvA film, and that the heat treatment temperature is 200°C or higher because the heat setting effect is sufficient and also in terms of practical dimensional stability. It is suitable for Furthermore, as will be described later, it is preferable that the stretching ratio is 5.5 times or more, more preferably 6 to 6.5 times, since it provides excellent practical strength and dimensional stability, especially dimensional stability. be.

In order to laminate and adhere the resulting PVA-based axially stretched and heat-treated film to the warp and weave, a PVA-based binder, which is the same material in terms of hygroscopicity, water absorption, moisture permeability, durability, and transparency, is used. Furthermore, at least one pVA-based axially stretched and heat-treated film may be laminated and bonded to the warp and warp, and in some cases, many more may be laminated and bonded together. It has excellent moisture permeability, weather resistance, and infrared rays (heat rays) shielding properties in the 6-17 micron wavelength range, making it highly dehumidifying, anti-condensing, durable, and heat-retaining, making it extremely useful as an agricultural covering material. However, it has poor water resistance, poor practical dimensional stability due to moisture absorption, blocking and significant swelling when absorbed, and furthermore, poor practical strength due to embrittlement at low temperature and low humidity. Of course, even if it is composited with other hydrophobic films, it cannot be put to practical use.

In order to eliminate the drawbacks of such a PVA film and give it practicality as an agricultural covering material, the PVA film is uniaxially highly stretched and then heat treated. The inner layer covering material used in the double-covered house for pickling industry of the present invention is made by laminating BLJIK bodies in the warp and warp. That is, the PVA film is stretched and heat treated to increase the degree of crystal orientation and crystallinity, thereby imparting water resistance.However, the stretched PVA film, on the other hand, absorbs moisture, and upon drying after absorbing water, the elongated molecules elongate. To avoid this, the degree of crystal orientation must be at least 0.92, preferably 0.94.
As mentioned above, it is important to carry out uniaxial high-stretching and heat treatment so that the degree of crystallinity is at least 0.47 or higher, preferably 0.50 or higher. By setting the degree of crystal orientation to 0.92 or more and the degree of crystallinity to 0.47 or more, the shrinkage due to the molecular relaxation phenomenon of the stretched and heat-treated film made of P'VA is about 2 to 6%.
The agricultural coating material of the present invention can be applied as a single material for the following purposes, but achieving this will vary slightly depending on the film forming conditions of the pvA film.
Usually the stretching ratio is at least 5.5 times or more, preferably 6 to 6
, it is necessary to increase the heat treatment temperature to 200° C. or higher by 5 times.

Naturally, if the stretching ratio and heat treatment temperature are further increased, the degree of crystallinity due to crystal orientation and elutriation will further increase, and water resistance and practical dimensional stability will be improved, but production stability and thermal decomposition 9, the stretching ratio is generally 6.5~
The heat treatment temperature should be up to 7 times as high as 220 to 250℃. By stacking and bonding at least one sheet with the drawing axis shifted, preferably orthogonally stacking and bonding each sheet, the single-fissure strength is improved. As a material, the PVA-based axially stretched, heat-treated film laminated material has excellent dehumidification, dew condensation prevention, durability, and heat retention, but it also has excellent water resistance, practical dimensional stability, and mechanical strength. As will be described later, it exhibits effective characteristics when used in the agricultural covering material of the present invention.Furthermore, the warp-warp laminate of the above-mentioned PVA-based axially stretched and heat-treated film is hard and somewhat lacking in flexibility. In order to improve this, the PVA-based axially stretched and heat-treated film is made with a plurality of substantially straight and fine cuts in the same direction as the molecular arrangement, and these cuts impart flexibility. and more preferred. Moreover, such a substantially straight and fine cut t1. It is preferable that the mesh length is 5 to 100 ai, and 5) PVA system-axial height stretching, which can be obtained with a small size.
The flexibility of the heat-treated film in the warp F4 lamination is somewhat opaque, and if it is larger than 100 mm, the raw texture of the warp lamination adhesive tends to become unstable.

Furthermore, it is preferable that the substantially straight and fine cuts be made at intervals of α5 to 20 mm in the direction of the PVA-based axially stretched and heat-treated film, and preferably larger than 20 mm. The flexibility of the warp/warp laminate of the PVA yarn - axially stretched and heat-treated film is somewhat insufficient, and if it is smaller than I], 5B, there is a problem in production stability◎ Next, the agricultural covering material of the present invention The PVA-based reticulated nonwoven fabric used will be described in detail.

The PVA-based reticulated nonwoven fabric used in the present invention is the PVA-based PVA-based axially stretched and heat-treated film used in the production of warp and warp laminates.
It is made by laminating and adhering a net-like body obtained by stretching, splitting, heat-treating, and widening the same material as the VA-based film from warp to warp, and any known method may be used.

For example, the PV'A film is suitably heated at a temperature of 180'C or higher at least 5.5 times, preferably 6 times or more in the longitudinal direction.
After stretching the fibers to ~6.5 times and splitting them by cutting, needle brushing, filing, etc., heat treatment is performed at 200°C or higher, and then the width is widened to an appropriate ratio to form a coarse body. It is recommended that at least 1 x 1 x 1 x 2 x 2 x 2 x 1 x 2 x 1 x 2 x 2 x 2 x 1 x 2 x 2 x 2 x 1 x 2 x 2 x 1 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2. As will be described later, it is suitable when integrated with a hydrophobic film. Furthermore, it is also preferable that the heat treatment temperature is 20D° C. or higher, since the heat setting effect will be sufficient and the obtained reticulated nonwoven fabric will have good practical dimensional stability. The upper limit of the stretching and heat treatment temperature is a temperature that does not cause thermal decomposition, which is generally about 230°C.

However, to explain in more detail the aspect of the reticulated nonwoven fabric used in the present invention, as will be described later, the performance when integrated with a film made of a hydrophobic synthetic resin to form the agricultural covering material of the present invention is as follows. It is preferable that

That is, first of all, if at least 80% of the split fibers constituting the reticulated nonwoven fabric are generally 0.5 m or more in width, it will have excellent practical strength and will have a reinforcing effect when integrated with the hydrophobic film. Preferably, such a reticulated nonwoven fabric can be easily obtained by appropriately selecting a splitting device and splitting conditions.

In addition, it is preferable that the porosity of the reticulated nonwoven fabric be 50% or less in terms of the reinforcing effect on the hydrophobic film and the hygroscopicity, water absorption, and dew condensation prevention properties of the laminate obtained by integrating the adhesive. Alternatively, it may be a film-like material with a porosity substantially close to 0%. Such a curved nonwoven fabric can also be easily obtained by appropriately setting the width expansion ratio.

Furthermore, the reticulated nonwoven fabric used in the present invention is obtained by laminating a reticular body obtained by stretching, splitting, heat-treating, and widening a PVA-based film, one sheet each in the warp and the warp, or in some cases, a larger number of sheets, by a known method. It may be a bonded material, or even a material that has adhesive properties with the reticulated nonwoven fabric, such as vinylon thread or PVA-based stretched tape, may be inserted at appropriate intervals for 4+li strength. As a binder for adhering to grass, it is sufficient to use a material with adhesive properties, but it does not have weather resistance, moisture absorption,
In terms of water absorption, moisture permeability, and transparency, it is preferable to use a PVA-based binder, which is the same material.

The agricultural SN material of the present invention consists of the hydrophobic film described above and the P'+'A-based axial height stretched and heat treated film.
Both the layered body and the P'VA-based reticulated small reticular nonwoven fabric are made by adhering and integrating one pole, and the aspects and effects thereof will be described in detail below.

Any known method may be used to adhesively integrate the hydrophobic film and the T+ peak laminate of the P'VA-based interaxially stretched and heat-treated film or the PVA-based preformed nonwoven fabric, such as dry lamination or extrusion lamination.
However, in this case, it is preferable to use a polyurethane-based or polyester-based adhesive or a buff flyer to improve adhesion.

In addition, the composition of the agricultural covering material of the present invention includes a hydrophobic film, PVA yarn - axial height stretching, and the history of the heat-treated film (for personal use)
It may be one in which the body is adhered and integrated, or it may be one in which a hydrophobic Fino L membrane and a thin PVA-based non-woven fabric are adhered and integrated.

Furthermore, if necessary, a hydrophobic film, a laminate of a pvA-based axially stretched and heat-treated film with variable warp and weft, and a PVA-based C4-like nonwoven fabric may be bonded and integrated. However, in this case, the important point will be described later, but when the agricultural covering material of the present invention is made by pasting and integrating, at least one side is a PVA-based 1ill 1fl16 stretched, heat-treated film orthogonal laminate or a PVA-based reticulated film. Must be constructed of non-woven fabric.

As mentioned above, the characteristics and effects of the moderate material for industrial use of the present invention are that it is a composite of a hydrophobic film and at least one of a special warp-to-warp orthogonal laminate made of P'VA-based synthetic alloy resin or a reticulated nonwoven fabric. This will be explained below.Firstly, the agricultural coating material of the present invention is a conventional agricultural coating material made of conventional synthetic resins such as polyethylene, polyvinyl chloride, ethylene-acetate-e-vinyl copolymer, polyester, etc. This is because the drawbacks of commercial films, such as their lack of dehumidification, dew condensation prevention, and drip prevention properties, have been resolved. That is, since it is a product in which at least one of the above-mentioned polyethylene, polyvinyl chloride, ethylene-vinyl acetate copolymer, Bolier cross-layered material, or PVA-based silk-like nonwoven fabric is adhered and integrated, the PVA-based synthetic resin has Due to the extremely excellent moisture absorption, water absorption and dehumidification abilities, the agricultural covering materials of the present invention also have high dehumidification properties and high dew condensation prevention properties. A film made of the hydrophobic synthetic resin was coated with a PVA-based synthetic resin because the PVA yarn/single resin has excellent hygroscopicity, water absorption, and dehumidification properties. However, as mentioned earlier, PVA-based synthetic resins have poor water resistance, poor dimensional stability, and significant blocking properties when water is absorbed, so they are not suitable for agricultural coatings. It cannot be put to practical use as a material. According to the present invention (which is obtained by stretching, splitting, heat treating, and widening a PVA-based axial high-stretched heat-treated film or a PVA-based film, which is a special material characterized by a PVA-based synthetic resin) At least one PVA-based silk-like non-woven fabric formed by liquid-adhering 8 layers along a net-like body
Although seeds were used to make it practical for the first time, the water resistance of the net-based nonwoven fabric alone was improved, but it still lacks light resistance when used for covering the exterior of greenhouses, etc.
In particular, since there is a possibility that rainwater may enter the inside of the container, it is important to integrate it with the film made of the above-mentioned hydrophobic synthetic resin.

The second feature and effect of 2I-Hikari Tainorai Pantanshiba is that it has extremely low heat retention, and is highly effective in saving energy and energy. 1■ Infrared radiation mainly in the 6-17μ wavelength range that is the cause
It is made by adhering and integrating at least one type of PVA-based reticulated nonwoven fabric, which has extremely strong anti-irradiation properties, with a film made of a hydrophobic synthetic resin such as polyethylene, polyvinyl chloride, ethylene-vinyl acetate copolymer, polyester, etc. The industrial covering material of the present invention also has extremely good heat retention properties and is highly effective in saving energy.

As explained in detail above, the agricultural coating material of the present invention has excellent heat retention, dehumidification, and dew condensation prevention properties, and can be widely used in future agricultural management where energy conservation is essential.

Claims (1)

[Claims] (1) R) a hydrophobic synthetic resin film; and (B)
A laminate of a polyvinyl alcohol-based heat-treated film with an axially stretched height shifted from the drawing axis to the warp and warp, or (c) a net-like structure obtained by stretching, splitting, and heat-treating a polyvinyl alcohol-based film to widen its width to the warp and sJ-adhered to the warp and warp. Claim No. 1 (1), which is made of a non-woven fabric, ≠ 4 or more
Agricultural covering materials listed in ). (6) Polyvinyl alcohol-based axially stretched and heat-treated film has a plurality of substantially straight and fine cuts in the same direction as the molecular arrangement, Claims (1) to 1. Agricultural covering material according to any of paragraph (2). (4) The length of the substantially straight and fine cut is 5~
The agricultural covering material according to claim (5), which has a length of 100 m. (5) Substantially straight and fine cuts of 0.0 mm in the axial direction of the polyvinyl alcohol-based axially stretched and heat-treated film.
The agricultural covering material according to claim (3), which is applied at intervals of 5 to 20 m. (6) The reticulated nonwoven fabric has a porosity of 50% or less), and at least 80% is composed of split fibers having a width Q of 5 mm or more.
) to (5), agricultural covering materials and