JPS6365026B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an agricultural film with good droplet flow properties. More specifically, agricultural linear low density polyethylene (Linear Low Density Polyethylene) with substantially improved droplet
The present invention relates to a film (hereinafter referred to as L-LDPE). Conventionally, polyvinyl chloride film, polyethylene film, ethylene-vinyl acetate film, etc. have been used as covering materials for greenhouse cultivation such as agricultural greenhouses and tunnels. In recent years, L-LDPE, a type of polyethylene, has been put on the market, and this L-LDPE film has begun to be used in the field of agricultural covering materials due to its excellent tear strength, impact strength, and stiffness. When the L-LDPE film is used as a covering material, water in the soil condenses and forms water droplets on the film surface, which impairs light transmission into greenhouses and tunnels, adversely affecting crop growth. Problems have arisen due to so-called poor droplet flow properties of the film, such as condensed water droplets dripping off and damaging crops or becoming a source of disease. Methods for improving the droplet properties of L-LDPE films include (1) copolymerizing vinyl compounds such as vinyl acetate and acrylic acid to impart droplet properties, or (2) adding surfactants to L-LDPE films.
Method of coating on LDPE film, or (3) L-
There are methods such as mixing LDPE with a surfactant to make a film. However, although the method (1) of forming a copolymer improves the droplet flow properties slightly, it is still insufficient, and some kind of improvement in the droplet flow properties is required. In addition, in the method (2) of applying a surfactant, the droplet properties are good at the beginning of application, but the droplet properties disappear after a few days due to the surfactant being washed away or diffused. It is necessary to reapply the surfactant each time it disappears. Furthermore, the method (3) of mixing a surfactant to form a film has problems, such as poor compatibility between L-LDPE and the surfactant, and droplet flow lasting only for a short period of time. An object of the present invention is to obtain an L-LDPE film for agricultural use that has good droplet flow properties and maintains droplet flow properties for a long period of time. The present inventors developed agricultural L-LDPE with good droplet flow properties.
As a result of extensive research into the film, we found that by providing a resin layer containing a surfactant on one side of the L-LDPE film, the droplet flow properties were substantially improved, and surprisingly, the droplet flow properties were maintained for a long period of time. The present invention was completed based on this discovery. That is, according to the present invention, a base material layer mainly composed of L-LDPE and a layer consisting of a resin that is compatible with the base material layer and contains 0.01 to 8 parts by weight of a surfactant per 100 parts by weight of the resin are laminated. An agricultural film is obtained, which is characterized in that it is formed of (i.e., laminated). The agricultural film of the present invention has a base layer of L-
Although it is necessary that the base material layer is formed mainly of LDPE, it is of course possible that the base material layer is formed of L-LDPE alone. L-LDPE, which is used as the main material of the base material layer, is a type of low-density polyethylene, and is composed of ethylene and
-It is a copolymer with α-olefin such as butene and 1-octene. In L-LDPE, the main chains are connected almost linearly, and α copolymerizes in places.
- Compared to conventional low-density polyethylene, it has a side chain of an alkyl group based on olefin.
-LDPE has excellent tear strength, impact strength, and stiffness. Although any L-LDPE can be used in the present invention, one having a density of 0.900 to 0.935 g/cm ³ and a melt index of 0.1 to 15 g/10 minutes is preferred. In addition, L
−LDPE density and melt index are JIS
Measured according to K-6760 (polyethylene test method) (density: JIS K-7112, melt index: JIS K-7210 applied mutatis mutandis). Also, L-LDPE used as the main material of the base layer
Examples of resins used in blends include polyethylenes such as low-density polyethylene, medium-density polyethylene, and high-density polyethylene, ethylene-vinyl acetate copolymers, ethylene-α-olefin copolymers,
These include polypropylene, and these may be used alone or in combination of two or more. By blending these resins with L-LDPE, L-LDPE
Compared to using them alone, additives that are usually added to polyolefin resins, such as antioxidants such as phenol derivatives and ultraviolet absorbers such as benzotriazole derivatives, are prevented from bleeding, and their compatibility with resins containing surfactants is reduced. Favorable results such as improved performance may be obtained. In cases where there is a problem when using L-LDPE alone as a base material layer, L-LDPE
It is preferable to blend these resins.
The amount of resin blended into L-LDPE is
The same amount or less is preferable. If a resin such as polyethylene is blended in an amount exceeding the amount of L-LDPE, the excellent properties of L-LDPE will rapidly weaken and the properties of the base layer will become close to those of the blended resin. . The thickness of the base material layer is preferably 5 to 200 microns. In addition, in the case of forming a sheet-like film, it goes without saying that the base material layer may have a thickness of 200 μm or more.
Note that if the base material layer has a thickness of less than 5 μm, the strength is substantially insufficient and it does not function as a base material. The resin containing the surfactant is preferably a resin that is compatible with the L-LDPE layer. Particularly preferred resins include polyethylenes such as low-density polyethylene, high-density polyethylene, and medium-density polyethylene, ethylene-vinyl acetate copolymers, ethylene-α-olefin copolymers, and ionomer resins. “Compatible” mentioned here
This means that when an L-LDPE layer and a resin layer containing a surfactant are laminated, they have sufficient adhesion to prevent them from peeling off from each other. Not requested. The thickness of the resin layer containing surfactant is 5~
200 microns is suitable, preferably 5-100 microns. The thicker the surfactant-containing resin layer, the better the persistence of droplet properties, but if it is too thick, problems arise, such as impairing the properties of the base layer. It is better if it is approximately the same thickness or thinner than the base material layer. The surfactant used in the present invention may be an anionic, cationic, nonionic or amphoteric surfactant as long as it can provide droplet properties. Examples include: (a) Anionic surfactants: phosphoric acid esters such as sodium lauryl phosphate and polyoxyethylene-sodium lauryl phosphate; sulfuric acid esters such as sodium lauryl sulfate and sodium salt of sulfated oleic acid; Sulfonic acid salts such as sodium stearylsulfonate, dodecylbenzenesulfonic acid triethanolamine salt, sodium salt of dioctylsulfosuccinate, etc. (b) Cationic surfactants: lauryltrimethylammonium chloride, N,N-dimethyl-N
-(Hydroxyethyl)-3-(stearoamide)
- Quaternary ammonium salts such as propylammonium nitrate, 2-octadecyl-1-
Imidazoline derivatives such as (hydroxyethyl)-2-imidazoline, amines such as N,N-diethyl-(stearoamide)-methylamine hydrochloride, polyoxyethylene stearylamine, etc. (c) Nonionic surfactant: polyethylene glycol nonyl Polyethylene glycol ethers such as phenyl ether and polyethylene glycol stearyl ether, polyethylene glycol carboxylic acid esters such as polyethylene glycol stearate and polyethylene glycol dilaurate, glycerin monostearate, sorbitan monopalmitate, sorbitan tristearate, etc. Partial carboxylic acid esters of polyhydric alcohols, polyoxyethylene derivatives of partial carboxylic acid esters of polyhydric alcohols such as polyoxyethylene derivatives of sorbitan monostearate, polyoxyethylene derivatives of sorbitan monolaurate, N,N- G
(hydroxyethyl)-laurylamide, N-
(2-Bidroxypropyl)-Amide derivatives such as stearamide, polyethylene oxide-
Block copolymers of polypropylene oxide, etc. (d) Amphoteric surfactants: N-lauryl-3-iminodipropionic acid and its sodium salt, N-carboxymethyl-N,N-dimethyl-N-dodecyl ammonium hydroxide, etc. Betaine compounds, 2-octadecyl-1-(hydroxyethyl)-2-imidazoline sulfate ester, 2-dodecyl-1-carboxymethyl-
Examples include imidazoline derivatives of 1-(hydroxyethyl)-2-imidazolinium hydroxide and its metal salts such as sodium and calcium. These may be used alone or in combination of two or more. The amount of surfactant used is suitably 0.01 to 8 parts by weight, preferably 0.1 to 5 parts by weight, per 100 parts by weight of the resin containing the surfactant. Usage is 0.01
If the amount is less than 1 part by weight, no droplet flow properties are obtained, or even if they are obtained, the droplet flow properties are insufficient, and the droplet flow properties are lost within a few days. Further, if the amount used exceeds 8 parts by weight, problems such as devitrification of the film and peeling of the two laminated layers occur. Conveniently, the surfactant is added during the compounding process. Further, any method for adding the surfactant can be used as long as it can be uniformly dispersed. The agricultural film of the present invention requires a base material layer and a resin layer containing a surfactant to be formed in a layered manner, and the method for manufacturing this agricultural film includes inflation processing, L- A method of forming films using normal processing methods such as T-die processing and bonding them together using dry lamination or heat lamination.
L-
There are already known methods such as a method of simultaneously extruding an LDPE layer and a resin layer containing a surfactant to form a film, and any of these methods can be used. When a resin layer containing a surfactant is provided on one side of the base film as in the present invention, droplet flow properties can be obtained only on the required surface, and surprisingly, the droplet flow properties can be maintained for a long period of time, which is advantageous. Furthermore, the agricultural film of the present invention has the advantage of having excellent properties such as tear strength, impact strength, and stiffness that L-LDPE films have. The following examples illustrate the usefulness of the present invention.
These examples are illustrative and do not limit the scope of the invention. Examples of production of agricultural films of the present invention are shown in Examples, and Tables 1 to 5 show the test results of droplet flow properties of the obtained films. Table 1 shows the droplet flow test results for films with different surfactant-containing resins, and Table 2 shows the droplet flow test results for films with different resins in the base layer mainly composed of L-LDPE. The test results of the third
The table shows the droplet flow test results for (1) films with different thicknesses of the base layer and resin layer containing surfactant, and (2) films with different amounts of surfactant added. Table 4 shows the droplet flow test results of films using different types of surfactants.
Furthermore, for comparison, Table 5 shows a film containing no surfactant at all (Comparative Example 1), a film in which a surfactant is simply kneaded into L-LDPE (Comparative Example 2),
The test results of droplet properties of commercially available agricultural films sold as droplet type (Reference Examples 1 to 3) are shown. Note that the droplet flow properties shown in Tables 1 to 5 were determined by the following test method. Low-temperature sustained droplet flow (5°C method) Pour 200ml of 5°C water into a 300ml beaker and cover with a sample film, with the surface of the resin containing the surfactant facing inside. Place this beaker in a water tank kept at 5°C and submerge it almost to the surface of the water.
The beaker and water tank are placed in a thermostatic chamber kept at 0° C., and the droplet flow properties of the film are observed after a predetermined period of time. Continuous hot water droplet flow (50℃ method) Pour 200ml of 50℃ hot water into a 300ml beaker and cover with a sample film with the surface of the resin containing surfactant facing inside. Immerse this beaker in a hot water tank maintained at 50°C up to almost the level of the warm water inside the beaker.
The beaker and hot water tank are placed in a constant temperature room kept at 15°C, and the droplet flow properties of the film are observed after a predetermined period of time has elapsed. Example 1 A commercially available L-LDPE film (thickness:
25μ, product name Lineace, manufactured by Sunwell Industries Co., Ltd. Melt index 2.0g/10 minutes, density 0.92
On this film, 1.0 part by weight of the nonionic surfactant sorbitan monopalmitate (trade name Span 40, manufactured by Kao Atlas Co., Ltd.) and low density polyethylene (trade name Mirason 45, Manufactured by Mitsui Polychemical Co., Ltd., melt index 1.5g/10 minutes, density 0.921g/ ^cm3 )
100 parts by weight of the mixture was used as a surfactant-containing resin and extrusion laminated to obtain a film with a thickness of 50 μm. Example 2 In Example 1, instead of low density polyethylene, ethylene-vinyl acetate copolymer (trade name Evaflex P1403, manufactured by Mitsui Polychemical Co., Ltd., melt index 1.4 g/10 minutes, density 0.93 g/cm ³ ,
A film with a thickness of 50 μm was obtained in the same manner as in Example 1, except that vinyl acetate (14%) was used as the surfactant-containing resin. Example 3 In Example 1, ionomer resin (trade name Himilan 1706, manufactured by Mitsui Polychemical Co., Ltd., Melt Index) was used instead of low density polyethylene.
A film with a thickness of 50 μm was obtained in the same manner as in Example 1, except that 0.7 g/10 minutes, density 0.97 g/cm ³ , zinc salt type of ethylene-methacrylic acid copolymer) was used as the surfactant-containing resin. Ta. Example 4 In Example 1, ionomer resin (trade name Himilan 1707, manufactured by Mitsui Polychemical Co., Ltd., Melt Index) was used instead of low density polyethylene.
A film with a thickness of 50 μm was prepared in the same manner as in Example 1, except that 0.9 g/10 minutes, density 0.95 g/cm ³ , sodium salt type of ethylene-methacrylic acid copolymer) was used as the resin layer containing a surfactant. I got it. Example 5 In Example 1, high-density polyethylene (trade name Hi-Zex) was used instead of low-density polyethylene.
5000S, manufactured by Mitsui Petrochemical Industries, Ltd., melt index: 0.8 g/10 min, density: 0.96 g/cm ³ ) was used as the surfactant-containing resin, but the same method as in Example 1 was used to prepare a 50 μm thick sheet. I got the film. Example 6 In Example 1, instead of the commercially available L-LDPE film (trade name Lineace), L-LDPE (trade name Ultzex 3021F manufactured by Mitsui Petrochemicals Co., Ltd., melt index 2.1 g/10 minutes, density 0.92) was used.
A film with a thickness of 25 μm was prepared by the inflation extrusion method using 3.0 g/cm ³ ), and a film with a thickness of 50 μm was obtained in the same manner as in Example 1, except that this film was used as the base layer. Example 7 In Example 1, instead of the commercially available L-LDPE film (trade name Lineace), 70 parts by weight of L-LDPE (trade name Ultsex 3021F) and 30 parts by weight of low-density polyethylene (trade name Mirason 45) were blended. A film with a thickness of 25 μm was prepared using the resin by the inflation extrusion method, and the thickness was adjusted in the same manner as in Example 1 except that the film was used as the base layer.
A 50μ film was obtained. Example 8 In Example 1, instead of the commercially available L-LDPE film (trade name Lineace), 80 parts by weight of L-LDPE (trade name Ultzex 3021F) and 20 parts by weight of high-density polyethylene (trade name Hizex 5000S) were blended. A film with a thickness of 25 μm was prepared using the resin by inflation extrusion, and a film with a thickness of 50 μm was obtained in the same manner as in Example 1, except that this film was used as the base layer. Example 9 In Example 1, instead of the commercially available L-LDPE film (trade name Lineace), 70 parts by weight of L-LDPE (trade name Urtozex 3021F) and ethylene-vinyl acetate copolymer (trade name Evaflex) were used.
P1403) was blended with 30 parts by weight, and using the resin, a film with a thickness of 25μ was created by the inflation extrusion method, and a film with a thickness of 50μ was prepared in the same manner as in Example 1, except that the film was used as the base layer. I got the film. Example 10 In Example 1, instead of the commercially available L-LDPE film (trade name Lineace), 80 parts by weight of L-LDPE (trade name Urtozex 3021F) and polypropylene (trade name Mitsui Noblen FL-100, manufactured by Mitsui Toatsu Chemical Co., Ltd.) were used. Company-made, melt index 8g/10
minutes, density 0.91g/cm ³ ) and 20 parts by weight,
Using the resin, a film with a thickness of 25μ was created by the inflation extrusion method, and the thickness was adjusted in the same manner as in Example 1 except that the film was used as the base layer.
A 50μ film was obtained. Example 11 In Example 1, a film with a thickness of 50 μm was created by the inflation extrusion method using L-LDPE (trade name Ultxex 3021F) instead of the commercially available L-LDPE film (trade name Lineace), and A film with a thickness of 7 μm was obtained in the same manner as in Example 1 except that it was used as a material layer. Example 12 In Example 1, a film with a thickness of 50 μm was created by the inflation extrusion method using L-LDPE (trade name Ultxex 3021F) instead of the commercially available L-LDPE film (trade name Lineace), and A film with a thickness of 100 μm was obtained in the same manner as in Example 1 except that it was used as a material layer. Example 13 A film with a thickness of 50 μm was obtained in the same manner as in Example 1, except that the amount of sorbitan monopalmitate used was 0.1 parts by weight. Example 14 A film with a thickness of 50 μm was obtained in the same manner as in Example 1, except that the amount of sorbitan monopalmitate used was 0.2 parts by weight. Example 15 A film having a thickness of 50 μm was obtained in the same manner as in Example 1 except that the amount of sorbitan monopalmitate used was 3 parts by weight. Example 16 A film with a thickness of 50 μm was obtained in the same manner as in Example 1, except that the amount of sorbitan monopalmitate used was 5 parts by weight. Example 17 In Example 1, the nonionic surfactant polyethylene glycol nonyl phenyl ether (trade name: Neugen) was used instead of sorbitan monopalmitate.
A film with a thickness of 50 μm was obtained in the same manner as in Example 1, except that EA120 (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) was used. Example 18 The thickness was determined in the same manner as in Example 1 except that an anionic surfactant alkyl phosphate ester (trade name Erectol #100, manufactured by NOF Corporation) was used instead of sorbitan monopalmitate.
A 50μ film was obtained. Example 19 A sample was prepared in the same manner as in Example 1 except that an amphoteric surfactant of an imidazoline derivative (trade name Rheostat 53, manufactured by Lion Yushi Co., Ltd.) was used instead of sorbitan monopalmitate in Example 1, but the thickness was 50 μm.
I got the film. Example 20 In Example 1, instead of sorbitan monopalmitate, the cationic surfactant NNN-trimethyl-3-(laurylamide)-propionic ammonium, methyl sulfate (trade name Elegan R-
A film with a thickness of 50 μm was obtained in the same manner as in Example 1, except that 115 (manufactured by NOF Corporation) was used. Comparative Example 1 A commercially available L-LDPE film (trade name: Lineace, thickness: 25 μm) that does not contain a surfactant shows no droplet flow. Comparative example 2 L-LDPE (product name Urtozex 3021F) 100
A mixture of 1 part by weight and 1.0 part by weight of sorbitan monopalmitate (trade name Span 40) was subjected to inflation processing to obtain a film with a thickness of 50 μm. The resulting film did not have sufficient droplet flow properties and disappeared within a few days. (See Tables 1 and 5) Reference example 1 Commercially available agricultural polyethylene film (trade name: Nohpoly, thickness 50μ, droplet type, manufactured by Toyo Polylon Co., Ltd.) exhibits a droplet function, but its sustainability is poor. is inferior to the agricultural film of the present invention. (See Table 5) Reference Example 2 Commercially available agricultural ethylene-vinyl acetate copolymer film (trade name: Nosakubi, thickness 50μ, droplet type,
(manufactured by Toyo Polylon Co., Ltd.) exhibits a droplet function, but its durability is slightly inferior to that of the agricultural film of the present invention. (See Table 5) Reference Example 3 Table 5 shows the test results of a commercially available agricultural vinyl chloride film (trade name: Mitsui Vinyl, thickness 50μ, droplet type, manufactured by Mitsui Toatsu Chemical Co., Ltd.). Notes on Tables 1 to 5 (1) The amount of surfactant added (phr) is parts by weight based on 100 parts by weight of resin. Note (2) The symbol written in the resin name indicates the following resin. L-LDPE: Linear low-density polyethylene LDPE: Low-density polyethylene HDPE: High-density polyethylene EVA: Ethylene-vinyl acetate copolymer PP: Polypropylene PE: Polyethylene PVC: Polyvinyl chloride Note (3) In the droplet property section 1H indicates the first hour, 1W indicates the first week, 3W indicates the third lap, and 5W indicates the fifth week. In addition, the degree of droplet flow was indicated by ◎, 〇, △, and ×. ◎; No water droplets adhere to the film.
Leak and be transparent. 〇: No water droplets adhere to the film,
It flows out, but the way it flows out is a little slow. Δ; Water droplets partially adhere to the film and flow out in long streaks. ×: Water droplets adhere to the entire surface of the film and do not flow out.

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[Table] As seen in Comparative Example 2, when a surfactant is simply added to L-LDPE, the initial droplet flow properties of the film obtained are not only inferior to the agricultural film of the present invention, but also The duration of sex is also short and problematic. However, the agricultural film of the present invention, in which a layer made of a resin containing a surfactant is provided on one side of a film mainly made of L-LDPE, is inferior to commercially available agricultural polyvinyl chloride resin films with good droplet properties. There was no difference in droplet flow, and there was almost no difference in the duration of droplet flow. Furthermore, as a result of subjecting the films obtained in these Examples to a one-year outdoor extension test, the droplet flow properties were good during the test period, and it was found that the commercially available agricultural polyvinyl chloride films (trade name) with good droplet flow properties were Mitsui Vinyl, manufactured by Mitsui Toatsu Chemical Co., Ltd., thickness 50μ, droplet type)
It was found that there is no inferiority in comparison to the commercially available droplet type agricultural polyethylene film and agricultural ethylene-vinyl acetate film. As described above, the agricultural film of the present invention has good droplet flow properties and maintains droplet flow properties for a long period of time, which is unimaginable when surfactants are mixed into conventional L-LDPE films. It is something.

Claims (1)

[Scope of Claims] 1. A base material layer mainly composed of linear low density polyethylene, and a resin that is compatible with the base material layer.
1. An agricultural film having good droplet flow properties, characterized in that it is formed of multiple layers of resin containing 0.01 to 8 parts by weight of a surfactant per 100 parts by weight. 2 Resins containing surfactants include polyethylenes such as low density polyethylene, medium density polyethylene, and high density polyethylene, ethylene-vinyl acetate copolymers, ethylene-α-olefin copolymers, ionomer resins, etc. The agricultural film according to claim 1, which is a species or a mixture of two or more species.