JPS59214Y2 - agricultural cladding - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to agricultural coverings.

More specifically, the present invention relates to agricultural covering materials having excellent light blocking properties, durability, heat insulation properties, heat retention properties, and the like.

In recent years, agricultural greenhouses and tunnels have been covered with covering materials to limit the amount of sunlight that passes through, allowing cultivation of cool vegetables such as honeydew, chrysanthemums, and spinach, mushrooms such as shiitake mushrooms and pine mushrooms, and sericulture. It is becoming more and more popular.

The covering materials used for such agricultural greenhouses and tunnels are
Light blocking properties and durability are required.

Conventionally used in this field are (a) silver polyethylene film (a film made by mixing metal aluminum powder with polyethylene, or a film made by vapor-depositing aluminum film on polyethylene film) and (b) silver polyvinyl chloride film. (Using polyvinyl chloride instead of polyethylene in the silver polyethylene in (a) above) Use of films that limit the transmission of sunlight or reflect sunlight; (c) Silver polyethylene films and silver PVC film and Yoshizu,
(2) use of cheesecloth with high light-shielding properties, and (e) use of cheesecloth with komo, jute bags, etc.

In the method of using silver polyethylene film or silver polyvinyl chloride film of (a) and (b) above,
These films have poor weather resistance, poor durability, and deteriorate in about 2 to 3 months in summer, so they are not practical.

For example, a coating agent made by mixing a specific amount of aluminum powder with an acrylic resin of a specific composition is applied to one or both sides of a soft polyvinyl chloride film to form a film. Vinyl films have been proposed (see Japanese Patent Publication No. 50-2184), but improvements in durability and strength are required.

As a film with improved durability and strength, an agricultural sheet material described in JP-A-49-124181 has been proposed, but when used as a covering material for a greenhouse, the inside of the greenhouse Water droplets remain on the fibrous base material facing the surface, reducing the strength of the fibrous base material and the adhesive strength between the film and the fibrous base material, resulting in poor durability and the propagation of various bacteria. There is a drawback.

On the other hand, when the base film is polyethylene, durability,
In addition to being a runner-up in terms of strength, it also lacked heat retention, so it had problems in terms of space, such as having to keep it warm in the winter.

Although cheesecloth and komo (see above) and (e) have excellent breathability, they are also water permeable, so moisture can easily enter the interior.
When it rains, rainwater enters greenhouses and tunnels, causing bacteria to propagate and severely inhibiting crop growth.

In view of the current situation, the inventors of the present invention completed the present invention as a result of intensive study and research into a covering material with excellent light-blocking properties, durability, heat insulation, and heat retention properties suitable for covering agricultural greenhouses and tunnels. The gist of the present invention is to polymerize an acrylic monomer mixture containing 80% by weight or more of methyl methacrylate and/or ethyl methacrylate on one side of the reinforcing fiber layer and on one or both sides of the flexible polyvinyl chloride film. A flexible polyvinyl chloride film is laminated on the acrylic resin obtained by applying a coating agent mixed with 10 to 50 parts by weight of aluminum powder per 100 parts by weight of this resin to form a coating film, The present invention relates to an agricultural covering material characterized in that a colored flexible polyvinyl chloride film is laminated on the other side.

The present invention will be explained in detail below.

In the present invention, the reinforcing fiber layer functions to improve the mechanical strength such as tensile strength and tear strength of the covering material.

Examples of materials that can be used as the reinforcing fiber layer include nonwoven fabrics, cheesecloth, and net-like materials made of natural or synthetic fibers.

The thickness of the thread and the size of the weave can be selected as appropriate.

By dyeing this reinforcing fiber layer in a black color, the light-shielding property of the covering material can be adjusted.

The coating material according to the present invention includes a soft polyvinyl chloride film (hereinafter referred to as "silver film") coated with a coating agent containing aluminum powder on one side of the reinforcing fiber layer.

) are laminated. The polyvinyl chloride used as the base material is a vinyl chloride homopolymer or a vinyl resin mainly composed of vinyl chloride, and is a copolymerizable monomer of vinyl chloride and other copolymerizable monomers such as vinyl acetate, vinyl chloride, ethylene, propylene, etc. Examples include copolymers of

These polyvinyl chlorides may be any of those obtained by conventionally known polymerization methods such as emulsion polymerization, suspension polymerization, solution polymerization, and bulk polymerization.

In order to soften the polyvinyl chloride, 25 to 60 parts by weight of a plasticizer is added to 100 parts by weight of the polyvinyl chloride.

If the plasticizer is less than 25 parts by weight, the flexibility of the film
Cannot be used due to poor extensibility.

On the other hand, if the plasticizer is 60 parts by weight or more, the flexibility and extensibility of the film are greatly improved, but the strength is poor, and
Plasticizer blow-off from the film becomes severe, and even if a fairly large amount of anti-blocking agent is added, it becomes difficult to prevent the product film from becoming sticky.

Examples of the plasticizer used here include dimethyl phthalate, diethyl phthalate, dibutyl phthalate, cyclohex, sylphthalate-1, dibenzyl phthalate, butylbenzyl phthalate, butyl lauryl phthalate, lauryl phthalate/cicapril phthalate, dioctyl adipate, Examples include dioctyl sepagate, phosphates thereof, epoxies, polyglycol esters thereof, and sebacic acid esters, and these may be used alone or in combination of two or more.

When the coating material is applied to only one side of the film, 0.3 parts by weight per 100 parts by weight of the polyvinyl chloride.
~5 parts by weight of a water droplet adhesion inhibitor and 0.3 to 1 part by weight of an anti-blocking agent may be blended.

Furthermore, organometallic compounds containing tin, lead, cadmium, barium, calcium, strontium, etc., or inorganic or organic salts of these metals, as stabilizers and lubricants such as oleic acid, palmitic acid, stearic acid, etc. Salts such as lead, calcilum, barium, etc. may be added.

There are no particular restrictions on the method of processing polyvinyl chloride containing the above-mentioned substances into a film, and conventionally known calendering methods, inflation methods, T-die methods, etc. may be employed.

The thickness of the film suitable as a covering material is 0.03 to 0.5
It is mm.

The vinyl chloride film laminated on one side of the reinforcing fiber layer of the present invention is produced by applying the following coating agent to one or both sides of the film produced by the method described above to form a coating film. be.

That is, the coating agent used to form the coating film is
It is a specific acrylic resin mixed with a specific amount of aluminum powder.

This coating material is manufactured under specific conditions in which the acrylic resin, which is one of its components, contains 80% by weight or more of methyl methacrylate and/or ethyl acrylate among the acrylic monomers. It is necessary that

The remaining 20% by weight or less is made up of other acrylic monomers.

When a coating agent containing methyl methacrylate-1 and/or ethyl methacrylate as a main component is applied to a vinyl chloride film to form a coating film, the weather resistance of the film is greatly improved.

In addition, when copolymerized with other acrylic monomers mentioned below and used as coatings, the resulting film prevents plasticizer migration and volatility, and has anti-drop and anti-stick properties. This improves sustainability and, as a result, greatly contributes to improving weather resistance.

That is, in order to produce the acrylic resin forming the coating material, acrylic monomers that can be used simultaneously include acrylic acid, methacrylic acid, crotonic acid, itaconic acid, butyl methacrylate, 2-ethylhexyl acrylate, and hydroxyl. Examples include alkyl (meth)acrylates.

These acrylic monomers give flexibility to the coating film,
It plays a role in improving the adhesion between the coating film and polyvinyl chloride.

To obtain the acrylic resin used in these coating materials,
The acrylic monomer is charged into a polymerization can with a solvent or into a polymerization system with an aqueous medium, a polymerization initiator and, if necessary, a molecular weight regulator are added, and the polymerization temperature is set at a temperature above room temperature and a boiling point temperature of the monomer mixture. If the polymer is polymerized using a solvent, the obtained polymer can be used as it is, diluted by adding a new solvent, or taken out and made into a completely different polymer. Aluminum powder, which will be described later, is added after being dissolved in a solvent.

A polymer obtained by an emulsion polymerization method, a bulk polymerization method, or a suspension polymerization method is used by taking out the polymer and dissolving it in a solvent.

Examples of solvents that can be used during solution polymerization or for dissolving the polymer include organic solvents such as acetylene, methyl ethyl ketone, methyl isobutyl ketone, toluene, and benzene/anone.

The ratio of the polymer to the solvent is preferably in the range of 95 to 80 parts by weight of the solvent to 5 to 20 parts by weight of the polymer.

Aluminum powder is added to the polymer-containing solution prepared as above.

The aluminum powder can be in the form of scales of 250 to 400 meshes, or in the form of needles of about 250 to 500 meshes.

The scale-like aluminum helps to give the film a metallic luster, and the needle-like aluminum in other shapes helps to improve the light-shielding properties of the film.

It is preferable to use both scale-like and needle-like types of aluminum powder in combination, and each type can also be used individually.

The amount of aluminum fine powder used is the same as the amount of acrylic resin 5 above.
It is used in a ratio of 50 to 10 parts by weight to 0 to 90 parts by weight.

If the proportion of aluminum powder is smaller than this range, the light shielding property cannot be improved, and if it is larger than this range,
Since the light transmittance of the film is completely blocked, it is not suitable for the purpose of the present invention.

In order to apply the above-mentioned coating agent to the above-mentioned film, methods such as roll coating, knife coating, spray coating, and tab coating are appropriately employed.

Such a coating may be applied to one or both sides of the film, but coating only one side is superior in terms of cost and water drop resistance.

After applying such a coating material to a base film, the film is heated and dried to scatter the solvent in the coating material.

The drying temperature must be such that the film surface temperature is 70'C or higher, particularly preferably 10σC or higher.If the drying temperature is lower than this temperature, the solvent cannot be sufficiently scattered, and the tackiness of the product film cannot be reduced. .

On the other hand, if the temperature is 70°C or higher, the solvent will scatter, which is preferable, but if the temperature is particularly in the range of 10σ to 180°C, the surfaces of the base film and the coating film can be softened or melted and baked. This is preferable because the adhesion between the two is strengthened.

Further, the higher the drying temperature, the shorter the drying time, and a method of instant drying at a high temperature can be adopted.

As described above, the thickness of the coating film formed on the base film is preferably 1/10 or less of the thickness of the base film.

The thickness of the coating film is 1/10 or more of the base film,
Since there is a slight difference in flexibility between the base film and the coating film, bad phenomena such as the coating film peeling off easily or cracks occurring in the coating film occur.

In the covering material according to the present invention, a colored soft polyvinyl chloride film is laminated on the other side of the reinforcing fiber layer.

This colored soft polyvinyl chloride film, together with the reinforcing fiber layer, functions to improve the heat insulation properties of the covering material.

The colored flexible polyvinyl chloride may be a colored film before the aluminum coating is formed.

There are no particular restrictions on the coloring of the film, but it is preferably colored white or black in order to reflect or absorb heat rays.

An example of the covering material according to the present invention is shown in the drawings below.

FIG. 1 is an enlarged longitudinal sectional side view of an example of the agricultural covering material according to the present invention, in which 1 is a silver film, 1' is a coating film containing aluminum powder, 2 is a reinforcing fiber layer, and 3 is a colored polyester film. It is a vinyl chloride film.

The present invention is as described above, and has the following particularly remarkable effects, and its practical utility value is extremely large.

(1) Since the agricultural covering material according to the present invention has a reinforcing fiber layer in the intermediate layer, the tensile strength and tear strength are significantly improved compared to a film alone without this layer.

(2) Since the agricultural coating layer according to the present invention has a silver film formed on one side, this film blocks sunlight, making it suitable for use in cultivating agricultural products while blocking light.

(3) The agricultural covering material according to the present invention has a soft polyvinyl chloride film laminated on both sides of the reinforcing fiber layer, and since water droplets do not come into contact with the reinforcing fiber layer, there is no possibility of strength reduction or bacterial growth. No worries.

(4) The agricultural covering material according to the present invention has excellent heat insulation properties in all three layers, and since a slight air layer is formed in the reinforcing fiber layer, it also has excellent heat retention properties.

(5) Silver film has a structure in which aluminum powder is not blended with polyvinyl chloride film, but is blended with weather-resistant sacrylic resin, and this is coated on polyvinyl chloride film. Weather resistance is significantly improved compared to silver film formulated with

(6) The agricultural covering material according to the present invention is suitable as a covering material for agricultural greenhouses and tunnels for cultivating cool-season vegetables, mushrooms such as shiitake mushrooms and pine mushrooms, sericulture, and raising seedlings.

[Brief explanation of drawings]

FIG. 1 is an enlarged longitudinal sectional side view of one example of the agricultural covering material according to the present invention. In the figure, 1 is a silver film, 1' is a coating film containing aluminum powder, 2 is a reinforcing fiber layer, and 3 is a colored polyvinyl chloride film.

Claims (1)

[Scope of utility model registration request] This is added to an acrylic resin obtained by polymerizing an acrylic monomer mixture containing 80% by weight or more of methyl methacrylate and/or ethyl methacrylate on one side of the reinforcing fiber layer and on one or both sides of the soft polyvinyl chloride film. A flexible polyvinyl chloride film is laminated on which a coating film is formed by applying a coating agent containing 10 to 50 parts by weight of aluminum powder per 100 parts by weight of resin, and a colored flexible polyvinyl chloride film is laminated on the other side. An agricultural covering material characterized by being made by laminating films.