JPH08140498A - Agricultural covering material - Google Patents

Abstract

PURPOSE: To obtain an agricultural covering material having continuous projections on the flat surface of a film with a specified thickness and provided with embosses on the upper surface of the projections, improved in blocking phenomenon over a long period and easy to set up. CONSTITUTION: This agricultural covering material has continuous projections 2 on one side or both sides of a flat film 1 with a thickness of 0.2-0.5mm consisting of a synthetic resin such as flexible vinyl chloride resin or polyethylene, and also has embosses 3 on the upper surfaces of the projections 2. It is preferable that one or both of the surfaces of the film be provided with coating film (s) containing an acrylic resin made from e.g. butyl methacrylate.

Description

Detailed Description of the Invention

[0010]

TECHNICAL FIELD The present invention relates to an agricultural coating material. More specifically, by providing protrusions on one side or both sides of the film, and by further providing fine irregularities on the top of the protrusions, the blocking phenomenon caused by the overlapping of the films was stably improved for a long period of time. The present invention relates to an agricultural coating material.

[0011]

2. Description of the Related Art Agricultural coating materials used for greenhouses, greenhouses, and the like in general plant cultivation include soft vinyl chloride resin, polyethylene, ethylene-vinyl acetate copolymer, and the like. Among them, the soft vinyl chloride resin film has a good balance of transparency, heat retention, and physical strength and is relatively inexpensive, and therefore has become the mainstream of agricultural coating materials. Many agricultural coating materials cause blocking phenomenon due to overlapping of films,
In particular, in the soft vinyl chloride resin film, the blocking phenomenon remarkably occurs due to the seepage of the plasticizer. Also,
In order to prevent dust and dust from adhering to the film surface and maintain light transmittance for a long time, a mixture containing an acrylic resin is applied to the film surface as a dust-proof coating agent as a known method. In the process of imparting the flexibility and cold resistance of the soft vinyl chloride film to the mixture containing it, the glass transition temperature (Tg) is lowered, and when it is exposed to a high temperature, it becomes sticky and the blocking phenomenon remarkably occurs. Therefore, the blocking phenomenon is improved by adding or coating a compound called an antiblocking agent represented by a fatty acid amide compound on the surface or by using a dustproof coating agent having less stickiness. In addition, the blocking phenomenon is improved by a method such as providing fine unevenness on the surface of the film or providing a projection such as an agricultural coating material disclosed in JP-A-6-98643. be able to.

[0012]

[Problems to be Solved by the Invention] Among the use of covering materials in facility cultivation, especially for use in the side part of a house, a hoisting device or the like is installed for the purpose of temperature control and ventilation in the house. Open and close frequently. For this reason, although the blocking prevention performance of the film in the initial stage, which is related to workability such as wide processing and house extension work, is required, the blocking prevention performance that is stable and long-lasting is required. Nowadays, when there is a demand for a coating material that can be used for a long period of time, the importance of the continuous antiblocking property is increasing. However, most of the methods for improving the blocking phenomenon with an antiblocking agent use a method by addition, so that it takes time to develop the antiblocking performance, and the antiblocking performance decreases with time. However, there is a problem in that the expression of the effect is limited because it cannot be added in a large amount for the reason of impairing transparency. On the other hand, studies on dust-proof coating agents have been conducted day and night, but until the proposal of a coating agent that has dust-proofing performance for the initial period and long-term and can keep anti-blocking performance for the initial period and long-term. Has not arrived. In addition, the method of applying fine unevenness on the film surface is
The transparency is impaired as compared with ordinary general films, which poses a problem in the growth of crops and limits the range of use. Only by providing protrusions as disclosed in JP-A-6-98643, sufficient blocking properties can be improved. It has not been obtained yet.

[0013]

Means for Solving the Problems The present inventor has
The present invention has been completed by earnestly studying to improve the blocking property of the film stably over a long period of time and to improve the transparency. Hereinafter, the present invention will be described in detail. The agricultural coating material of the present invention has a film flat portion having a thickness of 0.2 to 0.5 m.
m, a synthetic resin coating material having continuous protrusions on one side or both sides, having a concave-convex texture on the upper portion of the protrusions and having a coating film containing an acrylic resin on one side or both sides of the film.

The protrusions of the agricultural coating material of the present invention have uneven creases on the upper portion (see FIG. 2) and indicate convex ridges with respect to the flat portion of the film (see FIG. 1). The shape of the protrusions is continuous, and may be linear or curved, and is not particularly limited to any shape such as a quadrangle, a pentagon, or a circle. Further, it is desirable that the projections intersect with each other at a curved intersection angle, and further, a curved surface having a radius of 1 mm or more in order to prevent accumulation of water, dust and the like adhering to the film surface. The agricultural covering material of the present invention is practically provided with a projection having an uneven texture on one surface or both surfaces thereof, and a projection on one surface. Further, it is preferable that the projecting surface is provided outside the house or the tunnel. The textured surface is generally called satin, and may be patterned. Paper sandpaper # 20-4
The surface roughness is preferably about 0. Agricultural coating material of the present invention, by having an uneven wrinkle on the top of the protrusions, film opening test, film peeling test, as seen in the film peeling test after accelerated weathering, stable anti-blocking performance. And does not hinder the transparency of the entire film.

As the coating material of the present invention, materials used for agricultural coating materials such as soft vinyl chloride resin, polyethylene, and ethylene-vinyl acetate copolymer can be used. Among them, the soft vinyl chloride resin film is preferable because it has a good balance of transparency, heat retention, and physical strength and is relatively inexpensive, and is represented by a fatty acid amide compound that does not cause transparency or other obstacles. It is preferred to combine antiblocking agents. Soft vinyl chloride resin contains stabilizers, stabilizing aids, antioxidants, lubricants, UV absorbers, surfactants, colorants, etc., as necessary, in addition to plasticizers such as vinyl chloride resin and phthalate ester. It is to be compounded.

The thickness of the flat portion of the film of the present invention is
It is 0.2 to 0.5 mm. By setting it in this range, it is excellent as a covering material for agriculture in terms of strength, heat retention, shielding against outside air, and handling, and it also hinders workability in the work of expanding the house and opening and closing work on the side of the house. There is no film weight.

The ratio of the projections having the uneven texture on the entire area of the film is preferably 10% or more and 30% or less, and more preferably 15% or more and 25% or less. When the content is within this range, the antiblocking performance is stably exhibited and the transparency of the entire film is not impaired. If the ratio of the projections to the total area of the film is increased, the transparency is lowered.

The agricultural coating material of the present invention preferably has a coating film of an acrylic resin on one side or both sides of the film, and further, a copolymer containing butyl methacrylate, ethyl methacrylate and methyl methacrylate as main components. It is preferable to have a coating film of a silicone-modified acrylic copolymer. The acrylic resin means an alkyl acrylate such as methyl acrylate, ethyl acrylate, butyl acrylate, 2 ethylhexyl acrylate, and / or methyl methacrylate,
Ethyl methacrylate, butyl methacrylate, 2
Polymers or copolymers composed of methacrylic acid alkyl ester such as ethylhexyl methacrylate, or a mixture of these polymers, preferably ethyl methacrylate, butyl methacrylate, methacrylic acid alkyl ester such as 2 ethylhexyl methacrylate and / Alternatively, it is a polymer or copolymer of methyl acrylate or a mixture of these polymers, and more preferably a copolymer containing butyl methacrylate, ethyl methacrylate and methyl methacrylate as main components. Further, examples of the monomer copolymerizable with the above-mentioned polymer or copolymer include α, β-unsaturated acids such as acrylic acid, methacrylic acid, itaconic acid, crotonic acid, maleic anhydride and fumaric acid, or esters thereof. Or hydroxyalkyl esters of α, β-unsaturated carboxylic acids such as 2-hydroxyethyl acrylate or methacrylate, 2-hydroxypropyl acrylate or methacrylate, ethylene, propylene,
vinyl compounds such as α-olefin, acrylic amide,
Examples thereof include vinyl monomers such as n-methylol acrylate and vinyl ether, vinyl esters such as styrene, α-methylstyrene, vinyltoluene, vinyl propionate, and vinyl vasaticate. The acrylic resin may be a blend of an acrylic polymer and a vinyl chloride resin.

Further, a silicone-modified acrylic copolymer may be coated. Such a silicone-modified acrylic copolymer [I] is a modified copolymer obtained by copolymerizing a silane compound and an acrylic acid compound. The silane compound is a reactive silane compound such as a vinyl group-containing silane, a hydrogen group-containing silane, an amino group-containing silane, a carboxy group-containing silane, a chloro group-containing silane, or a mixture thereof. Of these, vinyl group-containing silanes are preferable. The acrylic acid-based compound is acrylic acid, acrylic acid ester, methacrylic acid, methacrylic acid ester, or a mixture thereof.

A more desirable copolymer of the silicone-modified acrylic copolymer [I] can be produced by copolymerizing the following monomers. Vinyl group-containing alkoxysilane Vinyl group-containing polysiloxane Methacrylic acid ester and / or acrylic acid ester having hydroxyl group Methacrylic acid ester and / or acrylic acid ester Among these, in order to obtain the best coating film physical properties, The use ratio in the production of the combined product is 0.5 to 20% by weight of a vinyl group-containing alkoxysilane, 0.1 to 20% by weight of a vinyl group-containing polysiloxane, and 10 to 30% by weight of a hydroxyl group-containing acrylate ester or methacrylic acid ester. It is preferable.

Examples of the vinyl group-containing alkoxysilane include: R ⁵ —SiX _a (R ³ ) _3-a (wherein R ³ is an alkyl group having 1 to 10 carbon atoms, an aryl group or an aralkyl group; A monovalent group selected, R ⁵ is an organic residue having a polymerizable double bond, X is a hydrolyzable group, and a is a silane compound represented by 1).
Specific groups for R ⁵ include And so on. Further, as a specific group of X, And so on. Specific examples of the vinyl group-containing alkoxysilane include methacryloxypropyltrimethoxysilane and vinyltrimethoxysilane.

The vinyl group-containing polysiloxane represented by A vinyl siloxane containing vinyl group at one end, or Is both terminal vinyl group-containing polysiloxane represented in (R ⁵ are same as R ⁵ of the alkoxysilane).

Specific examples of the vinyl group-containing polysiloxane include vinyl dimethyl polysiloxane having both ends or one end and methacryloxypropyl dimethyl polysiloxane having both ends or one end. The viscosity range of these polysiloxanes is preferably about 5 to 1000 cP. The molecular weight is preferably 200 to 100,000.

Specific examples of the acrylic acid ester and / or methacrylic acid ester having a hydroxyl group include methyl 2-hydroxyacrylate, ethyl 2-hydroxyacrylate, pentyl 2-hydroxymethacrylate, and butyl 2-hydroxymethacrylate. , 2-hydroxymethacrylic acid acrylic, 2-hydroxybenzylmethacrylic acid, and 2-hydroxyvinylmethacrylic acid.

The carbon number of the ester group of the methacrylic acid ester and / or the acrylic acid ester is 1 to 1
2 is preferable, and specific examples from this point onward include methyl acrylate, ethyl allylate, butyl acrylate, allyl acrylate, phenyl acrylate, methyl methacrylate,
Examples thereof include butyl methacrylate, pentyl methacrylate, lauryl methacrylate, vinyl methacrylate and allyl methacrylate. Two or more compounds may be used in combination.

In copolymerizing the compounds (monomers) of to, preferably, an organic acid having 3 or more carbon atoms is added in an amount of 0.1 to 5 of the polymerization mixture (the total amount of the compounds of Note.
Use by weight%. As the polymerization catalyst, 0.1 to 3% by weight, preferably 0.2 to 2% by weight, of a radical initiator such as benzoyl peroxide or azobisisobutyronitrile is used with respect to the total amount of all the monomers. Polymerization is bulk polymerization,
Although any solution polymerization can be carried out, solution polymerization is most preferred for the compounding process for coating. Examples of such a solvent include alcohols, and specific examples thereof include methanol,
Ethanol, isopropyl alcohol, n-butanol
And isoamyl alcohol. In addition, aromatic hydrocarbons such as toluene and xylene, esters such as ethyl acetate and butyl acetate, and ketones such as acetone and methyl ethyl ketone may be used alone or in combination.

The polymerization conditions (temperature, time) of the silicone-modified acrylic copolymer [I] are not particularly limited, but are usually 60 to 150 ° C. and 2 to 10 hours for completion. The coating film may be mixed with organopolysiloxane [II], which is a polymer containing a siloxane bond and having a molecular weight of 1000 or more. Among them, an organopolysiloxane having a siloxane bond and having at least one hydrolyzable group and at least one polyethylene oxide group in one molecule is preferable. The mixing ratio of the silicone modified acrylic copolymer and the organopolysiloxane is not particularly limited, but in order to obtain the basic physical properties and antifogging property as a coating film and other properties, it is 20: 1 to 1: 1. , Preferably from 10: 1
It is 2: 1.

The coating amount of this acrylic resin is the thickness
It is preferable to apply 0.2 to 10 μm. Coating amount is 0.2μ
If the amount is less, uniform coating becomes difficult and the dustproof effect is reduced. If the amount applied is more than 10μ, not only the cost increases but also gravure coating becomes difficult. It is easy to dissolve these acrylic resins in a solvent and apply them, and any solvent may be used as long as it can dissolve the polymer. Generally, acetone, methyl ethyl ketone, jetyl ketone, methyl isobutyl ketone, ethyl acetate, methyl acetate, propyl acetate, benzene, toluene, xylene,
Solvents such as methanol, ethanol, propanol, isopronol, tetrahydrofuran, dimethylacetoside, and methyl cellosolve may be used alone or as a mixture. The concentration at which the polymer is dissolved in the solvent is not limited by the properties of each polymer, but is preferably
Used at 10-30% by weight.

The agricultural coating material film of the present invention has a coating film containing an acrylic resin on at least one surface on one side or both sides, and it is preferable to apply it to the protruding surface.
Be sure to place the application surface outside the house or tunnel. The agricultural coating material of the present invention is obtained by forming a resin such as soft vinyl chloride into a film sheet by a processing facility such as an extruder equipped with a calendar roll or a T die, and embossing the formed film sheet in-line. It is practical to form a protrusion having a concave-convex texture on the upper part by equipment or an embossing device on a separate line. For coating the coating film, coating equipment such as a squeeze coater or a gravure coater can be used. The agricultural coating material of the present invention,
Make sure that the outside of the house or tunnel is the coated surface of the coating.

[0030]

EXAMPLES Hereinafter, the present invention will be specifically described based on Examples and Comparative Examples, but is not limited to the following examples as long as the gist is not exceeded. Incidentally, the evaluation of blocking prevention in Examples and Comparative Examples is carried out by a film opening test, a film peeling test, and the evaluation of continuous blocking resistance is carried out by a film peeling test after accelerated weathering, and is transparent. The haze (cloudiness value) test performed the evaluation of the property.

(Film opening test) One end of a film cut into a width of 200 mm and a length of 900 mm has a diameter of 19 mm.
It is fixed to the pipe of No. 1, and a weight of about 1100 g is attached to the other end, and a film for two rotations of the pipe is wound around the pipe. After spraying a sufficient amount of water on one side of the remaining film by spraying, wind the whole amount around the pipe with the weight lowered. Heat this in an oven at 70 ° C for 14 hours,
After that, it is left for 6 hours in a measuring room at a temperature of 23 ° C. and a humidity of 50%. The test piece is fixed to the lower stage of the tensile tester so that the pipe can rotate, the film is pulled out by 150 mm, and then fixed to the upper air chuck. By performing these operations, the peeling load required to open the film test body wound on the pipe was measured. The measurement measured the average peeling load from 20 mm to 70 mm from the measurement start point. Three sets of film test specimens were measured in one test, and the average value was used as the measured value. The smaller the measured value, the better the blocking prevention performance.

(Film peeling test) 50 mm × 120
Two pieces of film cut into mm are overlapped so that the surface with or without protrusions or the surface with or without the dustproof agent in contact with each other, and one side of the overlapped film 50 mm x 50 mm
The part of is sandwiched by smooth glass plates from above and below. Apply a load of 1 kg from the glass plate, leave it in a constant temperature and humidity layer at a temperature of 70 ° C and a humidity of 50% for 2 hours, then remove the load and set the temperature to 23.
Let stand for 24 hours in a measuring room at 50 ° C and 50% humidity. These operations were performed and the 180 degree peel load of the two laminated films was measured. The peeling load of three sets of film test bodies was measured for one test, and the average value was taken as the measured value. The smaller the measured value, the better the blocking prevention performance.

(Film peeling test after accelerated weathering)
JIS K 6732 (agricultural poly vinyl chloride film) described weather resistance tester (Cyshine carbon arc lamp type weather resistance tester) and test conditions (black panel temperature 63 ° C, water spray 1
The film was irradiated for 1000 hours for 2 minutes), and then the peeling load was measured by the same procedure as the film peeling test. (Haze test) Measured according to ASTM D 1003. Ten test pieces were sampled from arbitrary locations, and the average value of the measurement results of 10 test bodies was used as the measured value. The smaller the measured value, the better the transparency.

(Example-1) Manufacture of coating material 48 parts by weight of di-2-ethylhexyl phthalate was added to 100 parts by weight of polyvinyl chloride having an average degree of polymerization of 1300 (trade name: SM manufactured by Kyodo PVC Sales Co., Ltd.). Parts, 5 parts by weight of tricresyl phosphate, 3 parts by weight of epoxy resin-based resin plasticizer, 1.5 parts by weight of Ba—Zn-based composite stabilizer, 1.5 parts by weight of sorbitan monopalmitate, 0.5 parts by weight of methylenebisstearic acid amide and 0.1 parts by weight of benzophenone-based ultraviolet absorber were added to a Henschel mixer, and the mixture was stirred while heating and heating to obtain a soft vinyl chloride resin composition. It was Next, the obtained composition is formed into pellets by using an extruder, and then the pellets are formed into a film by a T-die method, and further subjected to embossing to form a film with protrusions shown in FIG. did. As shown in FIG. 2, the film had a thickness of 0.28 mm in the flat portion excluding the protrusions and a total thickness of the film including the protrusions of 0.38 mm.
4 mm, the width of the protrusion is 4.0 mm, and the top surface of the protrusion is finely textured to form a diamond shape with a side length of 45 mm. The ratio of the protrusion area to the entire film area is about 18
% Film. The film was subjected to a film breaking test, a film peeling test, a film peeling test after accelerated weathering, and a haze test, and the results are shown in Table 1.

(Comparative Example-1) The soft vinyl chloride composition described in Example-1 was molded into pellets by the same process, formed into a film by the T-die method, and further subjected to embossing treatment. A film having the same shape as that of Example 1 was formed, except that no fine uneven texture was formed on the upper portion. The same test as in Example-1 was conducted on the film, and the results are shown in Table 1. (Comparative Example-2) The soft vinyl chloride composition described in Example-1 was formed into pellets by the same process, and a film having a flat thickness of 0.28 mm was formed by the T-die method. The same test as in Example-1 was conducted on the film, and the results are shown in Table 1.

(Example-2) The soft vinyl chloride composition described in Example-1 was molded into pellets by the same process, formed into a film by the T-die method, and further embossed to give the width of the protrusions. Is 2.5 mm, and the ratio of the protrusion area to the entire film area is about 12%.
A film having the same shape as 1 was formed. The same test as in Example-1 was conducted on the film, and the results are shown in Table 1. (Example-3) The soft vinyl chloride composition described in Example-1 was formed into pellets by the same process, formed into a film by the T-die method, and further subjected to embossing treatment. A film having the same shape as in Example-1 was formed, except that it had a rhombic shape with a length of 80 mm, and the ratio of the area of the protrusions to the total area of the film was about 10%. The film was tested in the same manner as in Example-1, and the results were
Shown in the table.

Example-4 [Preparation of Silicon-Modified Acrylic Copolymer] 42.5 parts by weight of methyl methacrylate (hereinafter referred to as parts), 2-hydroxyethyl methacrylate 18.0 parts, and methacrylate n-.
Butyl 27.5 parts, n-butyl acrylate 5.0 parts, 3
-Methacryloxypropyltrimethoxysilane 5.0
Parts, methacryloxypropyldimethylpolysiloxane with one terminal (Mw = 5000) 1.0 part, methacrylic acid 1.0
And 1.0 part of azobisisobutyronitrile were mixed to prepare a monomer mixture for polymerization. A mixed solution of isopropyl alcohol and ethyl acetate (3/1 by weight) kept at 80 ° C. was added to this mixed solution to adjust the solid content concentration to 20%. This is designated as [A].

[Preparation of Organopolysiloxane] Hydrogen-silicon polysiloxane 26.3 having a viscosity of 20 cP and a content of hydrogen atoms bonded to silicon atoms of 0.38% by weight.
Part, CH ₂ = CHCH ₂ (OCH ₂ CH ₂ ) ₁₇ OCH ₃ 4
1 part, vinyltrimethoxysilane 7.4 parts, toluene 2
Then, 0.003 part of chloroplatinic acid was added as a catalyst, and the mixture was reacted at 100 ° C. for 4 hours. The toluene was removed from the reaction solution by heating under reduced pressure, and then a mixed solution of isopropyl alcohol and ethyl acetate (3: 1 by weight ratio) was added to adjust the solid content concentration to 20%. This is designated as [B].

The above-mentioned [A] and [B] were mixed in a weight ratio of 8: 1, and this was added to the film molded in Example-1,
Apply to the protrusion side by the gravure coater method,
A film having a coating film of 1 to 2 μ formed was obtained by drying at 0 ° C. for 1 minute. The same test as in Example-1 was conducted on the film, and the results are shown in Table 1.

(Comparative Example-3) The same dustproofing agent was applied to the film formed in Comparative Example-2 by the same procedure as in Example-4 to obtain a film having a coating film of 1 to 2 µ formed. It was The same test as in Example-1 was conducted on the film, and the results are shown in Table 1.

[0041]

EFFECTS OF THE INVENTION Like the present invention described in detail above,
By providing fine uneven textured protrusions on the film surface, the blocking phenomenon caused by the mutual overlapping of the films could be stably improved over a long period without impairing the transparency. Further, the blocking phenomenon of the film could be stably improved for a long period of time by applying a dustproofing agent composed of a mixture of acrylic copolymer and organopolysiloxane on one side or both sides of the film. Furthermore, the agricultural coating material of the present invention was easy to spread and could be used for a long period of time without stable blocking even after long-term use.

[0042]

[Table 1]

[Brief description of drawings]

FIG. 1 is a plan view of an agricultural covering material having a protrusion according to an embodiment.

FIG. 2 is a cross-sectional view of an agricultural coating material having a protrusion according to an embodiment.

[Description of sign]

 1 film flat part 2 film protrusion part 3 fine uneven texture

Claims (2)

[Claims] 1. The thickness of the flat portion of the film is 0.2 to 0.5.
mm, a synthetic resin covering material having continuous protrusions on one side or both sides, wherein the agricultural covering material has concave and convex wrinkles on the upper portion of the protrusions. 2. The agricultural coating material according to claim 1, which has a coating film containing an acrylic resin on one side or both sides of the film.