JPS5847411B2 - Agricultural coating film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an agricultural coating film made of an olefinic resin.

Conventionally, polyvinyl chloride film, polyethylene film, ethylene-vinyl acetate copolymer film, etc. have been used as coating films for agricultural greenhouses, tunnel houses, mulching, and the like.

By covering with these films, the inside of the greenhouse becomes hotter and humid than the outside air, which promotes plant growth.Due to this high temperature and humidity, water droplets form as condensation on the inner surface of the covering film, and this Water droplets scatter sunlight and impair the light transmittance of the coating film.

Therefore, conventional coated films contain a surfactant, and this surfactant migrates to the film surface to prevent the formation of water droplets.

That is, the surfactant causes water condensed on the film surface to flow along the film surface without forming a vortex, thereby improving so-called droplet flow.

However, in polyvinyl chloride film, the blended surfactant gradually migrates to the film surface and leaches out, so it has droplet properties over the life of the film (usually about 2 years), but polyethylene film In olefin resin films such as ethylene-vinyl acetate copolymer films and ethylene-vinyl acetate copolymer films, the blended surfactants migrate to the film surface in a short period of time and are washed away together with the condensed water. 6
10% for ethylene-vinyl acetate copolymer film
There was a drawback that the droplet-flowing property lasted only for about 14 months, after which water droplets formed on the inner surface of the coating film.

The present invention has been made in an effort to eliminate the drawback of short droplet persistence in conventional olefin resin films and to obtain a film with good droplet flow over the film's service life of about two years. The gist is,
The present invention relates to an agricultural coating film comprising a composition in which 0.1 to 5 parts by weight of an ionomer resin and 1 to 5 parts by weight of a surfactant are blended with 100 parts by weight of an olefinic resin.

In the present invention, the olefin resin is a homopolymer of α-olefin or a copolymer containing α-olefin as a main component with other monomers, such as low density polyethylene, medium density polyethylene, high density polyethylene, etc. Polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-acrylic acid ester copolymer, ethylene-propylene copolymer, ethylene-butylene copolymer, etc. are used alone or in combination. be able to.

Among these, low-density polyethylene and ethylene-vinyl acetate copolymers are preferred because they have excellent transparency and flexibility.

In addition, ionomer resins have a metal ion crosslinked structure between molecules, such as sodium ion type,
Zinc ion type products such as Surlyn (trade name) sold by DuPont are preferred, but sodium ion type products are preferred because they can improve droplet flow with a small amount.

Further, the surfactant may be any surfactant as long as it is blended and used in conventional agricultural polyethylene films and agricultural ethylene-vinyl acetate copolymer films, such as -COOH group, -COOM-SO3H group, Hydrophilic groups such as -OH group, -CONH2 group, -COOR-0 group, and -NH2 group, such as polyethylene glycol alkyl esters such as eryethylene glycol monostearate and polyethylene glycol dibehenate, polyoxyethylene Sorbitan fatty acid esters such as sorbitan monostearate and polyoxyethylene sorbitan monooleate, polyoxyethylene fatty acid ethers such as polyoxyethylene lauryl ether, glycerin fatty acid ethers such as glycerin behenyl ether, fatty acid alkylolamine condensates such as stearic acid diethanolamine, etc. etc. are used.

In the present invention, 0.1 to 5 parts by weight of an ionomer resin and 1 to 5 parts by weight of a surfactant are mixed with 100 parts by weight of an olefin resin.

If the blending ratio of the ionomer resin is less than 0.1 parts by weight, droplet persistence cannot be significantly improved no matter how the type and amount of surfactant is selected.

Furthermore, if the blending ratio of the ionomer resin exceeds 5 parts by weight, unless a large amount of surfactant is blended, the coated film will have poor droplet resistance (so-called initial droplet flow) during the first few months of use as an agricultural greenhouse or tunnel house. ) becomes worse.

That is, if the blending ratio of the ionomer resin is appropriate, the amount of surfactant blended is 1 to 5 parts by weight per 100 parts by weight of the olefin resin, so that the initial droplet flow properties are not impaired and sufficient droplet persistence is achieved. However, if the blending ratio of the ionomer resin exceeds 5 parts by weight, the initial droplet flow property deteriorates rapidly.

Therefore, in order to achieve this initial droplet flow, it is necessary to incorporate more than 5 parts by weight of surfactant, which not only makes the coating film expensive, but also requires that the film itself contains a large amount of surfactant. The inconvenience that the mixture becomes cloudy and opaque occurs.

Furthermore, if the blending ratio of the surfactant is less than 1 part by weight, droplet persistence over a long period of time will not occur, and the droplet flowability at the initial stage will also be poor.

If the amount exceeds 5 parts by weight, the resulting film becomes cloudy and its transparency deteriorates, and the strength of the film decreases, making it impossible to use it as an agricultural film.

In this way, 0.1 to 5 parts by weight of an ionomer resin and 1 to 5 parts by weight of a surfactant are blended with 100 parts by weight of an olefinic resin, and this composition is processed using the inflation molding method. By extrusion molding method such as die molding method or calendar molding method. Formed into a film.

As long as the composition contains an olefin resin, an ionomer resin, and a surfactant in a predetermined ratio, even if the ionomer resin is blended with an olefin resin containing a surfactant, the surfactant will not be added to the olefin resin. An ionomer resin containing may be blended.

As mentioned above, the agricultural coating film of the present invention has 0.1 parts by weight of ionomer resin per 100 parts by weight of olefinic resin.
It consists of a composition in which ~5 parts by weight and 1 to 5 parts by weight of a surfactant are blended, and by blending a specific proportion of ionomer resin, the surfactant blended in the film made of olefin resin can be removed. It can be gradually transferred to the film surface, resulting in a film that maintains its droplet properties throughout the life of the agricultural olefin resin film.

Next, examples of the present invention will be described.

Example 1 Low density polyethylene (manufactured by Mitsubishi Yuka, trade name Yucalon YF)
-30) Masterbatch containing 90 parts by weight of various surfactants shown in Table 1 (12.5 parts by weight of 100 parts by weight of the polyethylene kneaded with 25 parts by weight of various surfactants shown in Table 1) ionomer resin (manufactured by Mitsui Polychemical Co., Ltd., trade name: Surlyn 16) in the proportions shown in Table 1.
01, sodium ion type) and mixed with 0.01, sodium ion type) using a T-die extruder. Twenty types of films (film thicknesses 1 to 20) each having a thickness of 1 rtan were molded.

Using the 20 types of films obtained, we built a small tunnel house in the field (a container of 30 crrL x 50 cIrL filled with water and covered with film in the form of a tunnel).
We created a greenhouse and observed the adhesion of water droplets to the coating film without any ventilation in the greenhouse.

The state of adhesion of water droplets was determined by comparing with the state of adhesion of water droplets on a house coated with a commercially available polyvinyl chloride film (film A21) with good droplet persistence.

The results were as shown in Table I.

In addition, the adhesion state of water droplets in the table is judged as "◎" if there are no water droplets on the entire surface of the coated film, or "◎" if there are no water droplets on the entire surface of the coated film, and "◎" if there are water droplets locally attached to the inner surface of the coated film (an area of about 10φ on the inner surface). "○" means that water droplets have adhered to the inner surface of the coated film (approximately 30% of the inner surface area); "△" means that water droplets have adhered to the entire inner surface of the coated film; "x" means that water droplets have adhered to the entire inner surface of the coated film. ”.

From the results in Table 1, it can be seen that the water droplet adhesion state of the film containing an appropriate number of ionomer resins is the same as that of the tenon polyvinyl chloride film, and that the film containing no ionomer resin (Film AI, 5, 9, 1
It can be seen that the period until the water droplets adhere is longer than that in 3 and 17).

In addition, films containing 5.0 parts by weight of ionomer resin (Films A4, 8, 12, 16,
In 20), some water droplets were observed to adhere at the initial stage, but the adhesion of water droplets was slight, and the adhesion of water droplets disappeared in a short period of time, so there was no practical problem as an agricultural covering film. do not have.

In addition, in this Example 1, the adhesion state of water droplets was observed under the condition that no ventilation was performed in the house, so
It takes 4-5 months to 6 months for water droplets to become noticeable.
However, when the polyvinyl chloride film of Film A21 is used for ordinary agricultural greenhouses or tunnel houses, the dripping property continues for 1 year and 6 months to 2 years due to ventilation. .

Therefore, if the droplet shedding property lasts for a period equivalent to that of the film base 21, it will last for 1 year and 6 months to 2 years under actual usage conditions.

Example 2 Low density polyethylene (manufactured by Mitsubishi Yuka; trade name Yucalon YF-
30) Masterbatch containing 90 parts by weight of various surfactants shown in Table 2 (12.5 parts by weight of 100 parts by weight of the polyethylene kneaded with 25 parts by weight of various surfactants shown in Table 2) and various ionomer resins with the blended parts shown in Table 2 [manufactured by Mitsui Polychemical Co., Ltd., trade name Surlyn 1707 (sodium ion type), Surlyn 15]
57 (zinc ion type) and Surlyn 1652 (zinc ion type)] and molded using an inflation extrusion molding machine. Ten types of films (films A22 to A31) each having a thickness of 1 mm were molded.

The ten types of films obtained were tested for adhesion of water droplets in the same manner as in Example 1.

The results were as shown in Table 2.

Note that the adhesion state of water droplets in the table was determined in the same manner as in Example 1.

From the results in Table 2, it can be seen that even when various ionomer resins are blended, the droplet resistance becomes longer.

Example 3 A masterbatch containing a surfactant (100 parts by weight of the ethylene-vinyl acetate copolymer and polyoxy (kneaded 7 parts by weight of ethylene monooleate) 10.7 parts by weight and the third
Various ionomer resins with the blending parts shown in the table [manufactured by Mitsui Polychemical Co., Ltd., product name Surlyn 1601 (sodium ion type), Surlyn 1652 (zinc ion type)
] and then mixed with 0.0% using an inflation extrusion machine.
6 types of 1 mm thick films (film boiled 32~3
7) was molded.

The obtained film was tested for adhesion of water droplets in the same manner as in Example 1.

The results were as shown in Table 3.

Note that the adhesion state of water droplets in the table was determined in the same manner as in Example 1.

From the results in Table 3, it can be seen that the films containing ionomer resin (Films A33 to 37) have a higher droplet flow rate than the films containing no ionomer resin (Film A.3 2 ) in the ethylene-vinyl acetate copolymer. It can be seen that the sustainability is longer.

Claims (1)

[Scope of Claims] 1. An agricultural covering film comprising a combination of 0.1 to 5 parts by weight of an ionomer resin and 1 to 5 parts by weight of a surfactant to 100 parts by weight of an olefin resin. 2. The agricultural coating film according to claim 1, wherein the ionomer resin is of the sodium ion type.