KR101508490B1 - Improved heat retention and insulation films for agriculture - Google Patents

Abstract

The present invention relates to an agricultural film having improved heat insulation, the agricultural film comprising ethylene vinyl acetate (EVA) resin as a first component; surface-modified hydrophilic aerogel or silylated aerogel having a porosity of 80 to 99.8%, a particle size of 10 to 100 nm and a refractive index of 1.007 to 1.05, as a second component; polymers (EVA-g-MAH), as a third component, manufactured by grafting maleic anhydride on ethylene vinyl acetate (EVA) resin; and comprising or not comprising one or more components, as a fourth component, selected from polyethylene wax and silicone-modified polyethylene wax.

Description

TECHNICAL FIELD [0001] The present invention relates to an agricultural film composition having improved heat retention and insulation, and an agricultural film prepared therefrom.

TECHNICAL FIELD The present invention relates to agricultural films, and more particularly to agricultural film compositions used for greenhouses for cultivation of crops in vinyl houses, tunnels and the like, and agricultural films produced therefrom.

Greenhouse cultivation, in which crops and horticultural crops are grown using houses or tunnels, is used to artificially control the cultivation environment suitable for cultivation of crops, thereby cultivating the crops in a period in which cultivation is impossible or in a period in which productivity is low, Therefore, it is very important to install the facilities such as greenhouses and tunnels for greenhouse cultivation in consideration of characteristics for maintaining the cultivation environment such as solar light transmittance, thermal insulation, and thermal insulation, since it is necessary to maintain an environment suitable for cultivation of crops.

Polyvinyl chloride film, polyethylene film and ethylene-vinyl acetate copolymer film are mainly used for greenhouse cultivation and tunnels. In addition, additives for improving the functionality are added to the film production process, or two or more films are laminated Thereby improving the characteristics of the environment.

Background Art [0002] Prior art relating to agricultural films used for greenhouse cultivation, for example, in vinyl houses and tunnels is disclosed in Korean Patent Registration No. 10-0416863, for example, by blending a complex hydroxide condensed silicate specific to vinyl chloride resin, Discloses an excellent agricultural film having excellent thermal insulation properties and transparency. In a Korean Registered Patent Publication No. 10-0519401, a synthetic resin selected from the group consisting of ethylene-vinyl acetate copolymer, low-density polyethylene, linear low-density polyethylene, Absorbing agent, an average particle size of 2 to 20 占 퐉, hollow alumina silica-based hollow inorganic particles containing iron oxide are blended so that the ultraviolet shielding property and the heat insulating property are complementarily increased. Publication No. 10-0984329 discloses poly 0.5 to 1.0 part by weight of a near infrared absorbing dye and 0.01 to 0.2 part by weight of a fluorescent dye for light conversion are contained in 100 parts by weight of a synthetic resin base selected from the group consisting of tylene resin, polypropylene resin, ethylene-vinyl acetate copolymer resin and polyvinyl chloride resin Wherein the transmittance in the near infrared region of from 750 nm to 1,200 nm is 40 to 60%.

The present invention has been accomplished by developing a molding composition of an agricultural film suitable for a vinyl house, tunnel for greenhouse cultivation from an agricultural film composition with improved thermal insulation and heat insulation.

The present invention relates to an agricultural film composition used for greenhouse cultivation of agricultural crops, such as a vinyl house, a tunnel, etc., and an agricultural film produced therefrom. More specifically, the present invention relates to an agricultural film used for greenhouse cultivation, And to provide an agricultural film composition and an agricultural film produced therefrom that have improved heat insulation and heat insulation properties in accordance with visible light and infrared transmittance of the agricultural film.

The agricultural film composition having improved thermal insulation and heat insulation as a solving means for achieving the object of the present invention comprises an aerogel and an ethylene vinyl acetate (EVA) resin grafted with maleic anhydride to an ethylene vinyl acetate (EVA) resin EVA-g-MAH) or an olefin wax. Specifically, (a) 100 parts of an ethylene vinyl acetate (EVA) resin as a first component is blended with (b) a silylated aerogel (EVA-g-MAH) polymer grafted with ethylene vinyl acetate (EVA) resin as maleic anhydride as a third component, and (c) 20 to 50 parts by weight of an aerogel or a surface modified hydrophilic aerogel (Aerogel) (D) one or more components selected from a polyethylene wax and a silicone-modified polyethylene wax as a fourth component, wherein the skin is blended or not blended, A composition that consists of a functional aid.

The ethylene vinyl acetate (EVA) resin as the first component according to the present invention is prepared by copolymerizing ethylene and vinyl acetate. The EVA resin is superior in transparency and adhesive force, has excellent elasticity and low-temperature heat sealing property, And is used in various fields.

Aerogel, which is a second component of the agricultural film composition of the present invention, is a low-density material having a nanoporous structure, and has high light transmittance and thermal conductivity, and has a melting point of 1000 ° C or higher. Heat insulating material, noise shielding material, etc. In the present invention, the porosity is 80 to 99.8%, the particle size is 10 to 100 nm, and the refractive index is 1.007 to 1.05. A thermal conductivity of 10 to 20 mW / mK, and a surface modified hydrophilic aerogel (Aerogel).

Since the silylated aerogel has higher hydrophobicity due to the silylating agent than Aerogel, the silylated aerogel is more hydrophobic than Aerogel and can protect the pores of the Aerogel from the moisture in the air. Therefore, The porous property of the aerogel can be more completely realized.

In addition, the surface-modified hydrophilic aerogel is a hydrophilic modified surface of an airgel by a surfactant. Only the surface of the aerogel is hydrophilized and uniformly mixed with an organic material. When mixed with an organic material, a hydrophilic surfactant It is possible to prevent the organic material from penetrating into the airgel voids by the film, thereby maintaining the high specific surface area and porosity of the airgel, thereby realizing the characteristics inherent to the airgel.

The above silylated aerogels or surface modified hydrophilic aerogels are commercially available (ISA Corporation, REMTECH, etc.), and the higher the blending amount, the higher the thermal insulation and the heat insulation property. However, the ethylene vinyl acetate (EVA) resin , The mixing ability is deteriorated in a volume fraction of 50% or more, which makes it difficult to uniformly mix and deteriorate heat retention and heat insulation. Therefore, a preferable mixing amount of the above-mentioned aerogel is 100 parts by volume of the polyethylene glycol resin To 20 to 50 parts by weight .

The polymer (EVA-g-MAH) obtained by grafting ethylene vinyl acetate (EVA) resin with maleic anhydride anhydride as the third component selected in the present invention has high affinity with the ethylene vinyl acetate (EVA) (EVA) as a unit of volume. The mixing ratio of the ethylene vinyl acetate (EVA) is preferably in the range of 0.1 to 5 parts by weight, It is preferable to blend 2 to 8 parts with respect to 100 parts of the resin.

The polyethylene wax or the silicone-modified polyethylene wax, which is the fourth component, is a component that improves lubricity and releasability when formed into a film using a film composition. In addition, when the above-mentioned aerogels, (EVA-g-MAH) grafted with an anhydride maleic anhydride, the ethylene-vinyl acetate (EVA) resin as the third component, which acts to improve the dispersibility with the vinyl acetate And may be blended in an amount of 1 to 2 parts by weight based on 100 parts by weight of the polyethylene resin.

The agricultural film composition according to the present invention may further comprise a functional adjuvant as an additional component. The functional adjuvant may further comprise one or more components selected from a UV screening agent, an antioxidant, an antistatic agent and a heat stabilizer, (EVA) resin in an amount of 1 to 2 parts per 100 parts of the ethylene vinyl acetate (EVA) resin.

Further, the agricultural film of the present invention is used for a green house or a tunnel for greenhouse cultivation of a horticultural crop or a crop, Since the heat inside the house raised by the light transmission is not lost to the outside, the insulation is very excellent.

The present invention relates to a process for the production of a uniform composition of an ethylene vinyl acetate (EVA) resin and of an aerogel by selecting a polymer (EVA-g-MAH) grafted with maleic anhydride to an ethylene vinyl acetate (EVA) It is possible to improve the compatibility with the film and to ensure the inherent properties of the airgel without adversely affecting the physical properties of the film, and thus the heat inside the house, which is raised by the light transmission, It is characterized by the ability to produce this improved agricultural film.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a graph comparing the temperature changes of a vinyl house with heating of an agricultural film of the present invention. FIG.
FIG. 2 is a graph showing a comparative test of changes in the inner temperature of a greenhouse according to sunlight transmission of the agricultural film of the present invention. FIG.

Hereinafter, the present invention will be described in more detail with reference to Examples and Test Examples, and the present invention is not limited by the following description, and the units of the parts and percentages used in the present invention are not limited thereto unless otherwise specified. will be.

<Examples>

A molding composition having a composition ratio as shown in Table 1 below was melted and kneaded and then pelletized to prepare a master batch. Then, a 50 탆 thick agricultural film was produced by a conventional film forming method.

ingredient Composition ratio (unit: subcutaneous) Example 1 Example 2 Example 3 Where to buy EVA resin 100 100 100 Hankyung Pori Silylated aerogels 50 25 - ISA Corporation Hydrophilic aerogels - - 25 REM Tech Co., Ltd. EVA-g-MAH 6 3 3 Welcome Tech Olefin wax - One 2 Comet chemistry Silylated olefin wax - 2 Comet chemistry

&Lt; Test Example 1 >

For the warming test by heating, a simple vinyl house made of the agricultural film prepared in Example 1 and the commercially available agricultural film of 1 m x 1 m x 1 m (width x height x height) was installed in the room, The inside of the house was heated for about 1 hour by a heater of 350 W / h, and the temperature change in the interior of the greenhouse was observed. The results are shown in Table 2 below and attached as Fig. 1

division Temperature over time (℃) start 10 minutes 20 minutes 30 minutes 40 minutes 50 minutes 60 minutes Test Example 1 28.2 38.9 42.2 42.9 43.1 43.2 43.3 Comparative Example 1 28.3 36.8 39.1 39.5 39.7 39.8 39.9

As shown in Table 2 above, the simple test for a vinyl greenhouse having a volume of 1 m 3 was conducted. However, the internal temperature of the vinyl greenhouse of the present invention was 3.4 ° C Since the agricultural film of the present invention exhibits a higher room temperature at a temperature difference (maximum temperature), it can be seen that heat loss is small in the heating process due to the effect of improving heat insulation and warming property of the agricultural film of the present invention. It can be predicted that the required expenditure can be saved.

&Lt; Test Example 2 &

For the test of the temperature change of the inside of the house by the sunlight permeation, the greenhouse made of the agricultural film and the agricultural film prepared in Example 3 were each 1 m x 1 m x 1 m (width x height x height) After exposure to the sun for a period of time (about 6:00 on June 6, 2014), the temperature changes in each of the greenhouses were observed and the results are shown in Table 3 below and attached in FIG.

division Temperature over time (℃) start 10 minutes 20 minutes 30 minutes 40 minutes 50 minutes 60 minutes Test Example 2 33.3 47.4 47.8 47.1 47.8 48.8 50.1 Comparative Example 2 33.5 42.2 41.2 42.7 43.7 44.1 42.5

According to the above Table 3, it can be confirmed that the temperature of the inside of the house due to sunlight also keeps the temperature of the agricultural film of the present invention higher than that of the comparative example, and these test results show that the agricultural film of the present invention It can be predicted that the infrared transmittance and the heat insulating property are higher than those of the comparative example. Therefore, it can be seen that the agricultural film of the present invention is advantageous in terms of energy efficiency.

Claims (5)

(a) 100 parts of an ethylene vinyl acetate (EVA) resin as a first component,
(b) 20 to 50 parts of at least one component selected from surface-modified hydrophilic aerogels (Aerogel) and silylated aerogels (Aerogel) as the second component,
(c) 2 to 8 parts of polymer (EVA-g-MAH) grafted with ethylene vinyl acetate (EVA) resin to maleic anhydride as the third component
(d) 1 to 2 parts of at least one component selected from the group consisting of polyethylene wax and silicone modified polyethylene wax as the fourth component. delete The method according to claim 1, wherein the second component is a silylated aerogel having a porosity of 80 to 99.8%, a particle size of 10 to 100 nm, a refractive index of 1.007 to 1.05, and a fourth component is a silicone modified polyethylene wax Wherein the water-insoluble and water-insoluble antioxidant is used as an antioxidant. The method according to claim 1, wherein the second component is a surface modified hydrophilic aerogel (Aerogel) having a porosity of 80 to 99.8%, a particle size of 10 to 100 nm, a refractive index of 1.007 to 1.05, and a fourth component is a polyethylene wax An agricultural film composition improved in thermal insulation and insulation. An agricultural film having improved thermal insulation and heat insulation, which is produced by molding the agricultural film composition of any one of claims 1, 3, and 4.

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