JP3391197B2 - Agricultural polyolefin coating - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an agricultural polyolefin-based coating material for coating a house or a tunnel. More specifically, there is no deterioration in transparency or stickiness due to bleeding-out of an antifogging agent when it is spread in a house or a tunnel, and an agricultural polyolefin-based coating having good antifogging properties at low temperatures and good antifogging durability. Regarding materials

[0002]

2. Description of the Related Art A large amount of plastic film is used as a covering material for facility horticulture such as agricultural houses and tunnels, and typical ones are polyvinyl chloride film (hereinafter referred to as agricultural product) and polyethylene film (hereinafter referred to as agricultural product). Polyvinyl chloride), ethylene vinyl acetate copolymer film (hereinafter referred to as "agricultural vinyl chloride"), and the like. Among them, agricultural plastics have heat retention, transparency, toughness, anti-fog property, house adhesion and economy. It has excellent properties and is used most often. But,
Agricultural plastics are poor in workability and dust resistance due to the plasticizer contained in the film bleeding out and stickiness on the surface, and recently, various problems such as generating harmful gas at the time of incineration disposal are occurring, An alternative is desired.

On the other hand, although agricultural poly and agricultural vinegar have advantages in terms of workability, dustproofness, and disposal treatment over agricultural vinyl, they have antifogging properties, transparency, toughness, and house adhesion. There was the problem of being inferior. Among them, as the antifogging property, a method of kneading an antifogging agent having an antifogging property into a film is generally used, and in this antifogging agent, evaporated water is retained as water droplets on the film surface. It has the function of preventing the formation of water droplets and spreading the water droplets in a film shape, and causing it to flow down along the inner surface of the film.Agricultural poly consisting of an ethylene polymer does not have a polar group, so that it has antifogging properties. Therefore, it is difficult to control the bleed-out of the anti-fog agent added, and when the anti-fog agent is added to the extent that the anti-fog persistence is satisfied, the bleed-out becomes excessive, and the coating material becomes sticky and the workability is deteriorated. The transparency of the bleed-out material may be deteriorated due to the clouding phenomenon. If the addition amount is limited to prevent it, the antifogging agent will be washed away by water droplets,
There were problems such as not being able to expect sufficient anti-fog persistence. Up to now, a method for imparting anti-fogging property by kneading an anti-fog agent into an agricultural polyolefin-based coating material has been disclosed in, for example, JP-A-60
-26048, JP-A-3-59046, JP-A-3-59047, and the methods described in JP-A-3-59047, and those publications include a method of adding a specific antifogging agent in a specific compounding amount and a specific compounding ratio. .

[0004]

However, even in this method, the bleed-out of the anti-fog agent on the film surface cannot be properly controlled, and the transparency of the film due to clouding of the film due to excessive bleed-out of the anti-fog agent can be prevented. The current situation is that it includes problems such as deterioration in low-temperature anti-fog property and poor development of anti-fog persistence due to the occurrence of stickiness and insufficient bleed-out of anti-fog agent, and the polyolefin-based coating for agriculture still satisfies these problems. The material has not been obtained. As a result of intensive studies to solve these problems, the present inventors have found that by combining a specific anti-fog agent A and a specific anti-fog agent B with polyolefin, the surface of the coating material by bleeding of the anti-fog agent Avoid the problems of stickiness such as the decrease in transparency caused by cloudiness and the sticking of films. The inventors have completed the present invention by finding that the antifog property at low temperature is excellent, that the antifog effect lasts for a long period of time, and the antifog persistence does not decrease.

[0005]

The present invention has the following constitution. (1) An agricultural polyolefin-based coating material in which a polyolefin resin is blended with an antifogging agent A represented by the following chemical formula 3 and an antifogging agent B represented by the following chemical formula 4.

[Chemical 3]

[Chemical 4] (In the formula, R ¹ is an alkyl group having 8 to 22 carbon atoms, an alkenyl group or an acyl group, R ² is an acyl group, R ³ is a hydrogen atom or an acyl group, and a and b are a + b = 2 to 20. 1
The above integer, n is 2 or 3. (2) 0.5 to 5.0 parts by weight of the antifogging agent A and 0.1 to 1.0 parts by weight of the antifogging agent B relative to 100 parts by weight of the polyolefin resin.
The agricultural polyolefin-based coating material according to 1 above, which is blended in parts by weight and the melting point of the antifogging agent B is 35 ° C. or lower. (3) Polyolefin resin has a density of 0.880 to 0.935g /
cm ³ low density polyethylene, ethylene-vinyl acetate copolymer, density 0.940 to 0.965 g / cm ³ high density polyethylene,
The agricultural polyolefin-based coating material as described in 1 above, which comprises a polypropylene resin alone or in combination of two or more.

The present invention will be described in detail below. The polyolefin resin used in the present invention is a homopolymer of α-olefin or a copolymer of a heteromonomer having α-olefin as a main component. For example, propylene homopolymer or propylene and ethylene, 1-butene, 1 -Penten,
A propylene-based polymer which is a copolymer with 1-hexene,
Examples thereof include ethylene homopolymers and ethylene-based polymers which are copolymers of ethylene with 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, and vinyl acetate. These resins may be used alone. You may mix and use 2 or more types.

Of these, low-density polyethylene having a density of 0.880 to 0.935 g / cm ^{3 and} an ethylene-vinyl acetate copolymer having a vinyl acetate content of 30% by weight or less are preferable in terms of transparency, weather resistance and price. Of these, ethylene-vinyl acetate copolymer is particularly preferable in terms of transparency and flexibility.

The antifogging agent A used in the present invention is represented by the following chemical formula 5.
It is represented by a formula.

[Chemical 5] (In the formula, R ¹ is an alkyl group having 8 to 22 carbon atoms, an alkenyl group or an acyl group, R ² is an acyl group, R ³ is a hydrogen atom or an acyl group, and a and b are a + b = 2 to 20. The above integer, n is 2 or 3.) The amount of the antifogging agent A added is preferably 0.5 to 5.0 parts by weight with respect to 100 parts by weight of the olefin resin, and is within this range. Therefore, it is excellent in transparency, stickiness, and work of unraveling the film. Specifically, polyoxyethylene (2 mol) stearylamine monostearate, polyoxyethylene (2 mol) stearylamine monobehenate, polyoxyethylene (2 mol) laurylamine monostearate, polyoxyethylene (4 mol) Examples thereof include stearylamine monostearate, polyoxyethylene (8 mol) stearylamine distearate, and polyoxyethylene (2 mol) stearic acid amide. Among them, those having a melting point of 35 ° C. or higher are preferable.

The antifogging agent B used in the present invention is a compound represented by the following formula (6).

[Chemical 6] (In the formula, R1 is an alkyl group having 8 to 22 carbon atoms, an alkenyl group or an acyl group, a and b are integers of 1 or more for a + b = 2 to 20, and n is 2 or 3.) Examples of the agent B include polyoxyethylene (8 mol) stearylamine, polyoxyethylene (2 mol) laurylamine, and polyoxyethylene (2 mol) tallow amine. The melting point of the antifogging agent B is preferably 35 ° C. or lower, and the addition amount is 0.1 to 1.0 part by weight, and the melting point is 35 ° C.
The temperature below 10 ° C. is desirable. Within this range, the initial anti-fog property and white turbidity due to bleed-out can be prevented, the anti-fog agent B does not migrate much after the film is manufactured, and workability due to stickiness does not occur. The antifogging agent B used in the present invention is selected from nonionic surfactants, cationic surfactants, anionic surfactants, amphoteric surfactants, etc., depending on the degree of esterification of the antifogging agent and the chain length of the alkyl group. , The number of moles of alkylene oxide added, or their purities.

The coating material according to the present invention includes ethylene-α
An elastic copolymer such as an olefin-based copolymer or a diene-based copolymer may be added for the purpose of improving flexibility. Further, various additives such as heat retaining agents such as hydrotalcites and aluminum silicates, antifog agents, heat stabilizers, antioxidants, hindered amine light stabilizers, ultraviolet absorbers, slip agents and the like may be added.

The agricultural polyolefin coating material of the present invention can be produced by a known technique such as an inflation method or a T-die method. The corona discharge treatment after film formation can improve the effect of developing antifogging properties. Further, a dustproof coating agent or the like may be applied and dried to form a coating film on the surface. The agricultural polyolefin-based coating material of the present invention may be a single layer, but may be a laminated layer from the viewpoint of dust resistance, flexibility and strength. The covering material according to the present invention may be transparent, satin-finished or semi-finished, and can be used not only for covering agricultural houses (greenhouses), tunnels, etc., but also for mulching, bagging, etc. Also, the film thickness varies depending on the place of use, service life, etc.,
Generally, those having a thickness of about 0.05 to 0.3 mm are preferably used.

[0012]

EXAMPLES The present invention will be specifically described below with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

The melting point of the antifogging agent is measured by using a differential scanning calorimeter (manufactured by Perkin Elmer Co., Ltd.) at a heating rate of 20 ° C./min.
(JISK7121). Low temperature anti-fog slope 10
The film sample was fixed to a skylight of a water bath having a skylight with a diameter of 3 inches, and the antifogging property after 3 days was evaluated in 5 stages under the conditions of an environmental temperature of 5 ° C and a water temperature of 15 ° C. 5: A uniform water film was formed without water droplets attached. 4: Adhesion of water drops is less than 15%. 3: Adhesion of water drops is less than 40%. 2: Adhesion of water drops is less than 65%. 1: Adhesion of water drops is 65% or more. To maintain the low-temperature anti-fog property, the film sample was fixed to a skylight of a water bath having a 10-degree inclination and a 3-inch diameter skylight, and after 20 days at an environmental temperature of 23 ° C and a water temperature of 45 ° C, the environmental temperature was set to 5 again. The anti-fogging property after 3 days under the conditions of ℃ and water temperature of 15 ° C. was evaluated in the same manner as the low-temperature anti-fog property. The white turbidity of the film was evaluated by the haze value after 1 month of film formation. Anti-fog persistence was achieved by fixing the film sample to a water bath skylight with a 10-degree inclination and a 3-inch diameter skylight, and an ambient temperature of 23
C. and water temperature were kept at 45.degree. C. for 24 hours, and the period during which the antifogging property was maintained was evaluated. Film stickiness is a problem of poor workability due to stickiness when extending a house.
(Excellent), B (practical with some problems), C
Evaluation was made in 3 ranks (not practical).

Examples 1 to 14 Comparative Examples 1 to 7 Using a three-kind three-layer inflation extruder having one 65 mmφ extruder and two 45 mmφ extruders, a molding temperature of 170 ° C.
A blending example of the single layer or laminated film shown in Table 1, Table 2, Table 3, Table 4, and Table 5 having a thickness of 0.1 mm at a blow ratio of 2.5 and the evaluation results for each film are shown.

The agricultural polyolefin coating material of the present invention is used as an anti-fog agent exhibiting anti-fog properties by using a specific anti-fog agent and an anti-fog agent having a melting point of 35 ° C. or less to prevent the low-temperature anti-fog agent. Agricultural properties such as greenhouses, tunnels, etc. can be obtained because the appearance of cloudiness is rapid and the sustainability is good, and there is no loss of transparency or stickiness caused by clouding of the surface of the coating material due to bleeding of the antifogging agent. It can be suitably used as a covering material.

[Table 1]

[Table 2]

[Table 3]

[Table 4]

[Table 5]

Claims (3)

(57) [Claims] 1. An agricultural polyolefin coating material comprising a polyolefin resin and an antifogging agent A represented by the following chemical formula 1 and an antifogging agent B represented by the following chemical formula 2 in combination. [Chemical 1] [Chemical 2] (In the formula, R ¹ is an alkyl group having 8 to 22 carbon atoms, an alkenyl group or an acyl group, R ² is an acyl group, R ³ is a hydrogen atom or an acyl group, and a and b are a + b = 2 to 20. 1
The above integer, n is 2 or 3. ) 2. An antifogging agent A is added in an amount of 0.5 to 5.0 parts by weight, and an antifogging agent B is used in an amount of 0.1 to 100 parts by weight of the polyolefin resin.
The agricultural polyolefin coating material according to claim 1, wherein 1.0 part by weight is compounded and the melting point of the antifogging agent B is 35 ° C or lower. 3. The polyolefin resin has a density of 0.880 to
Low density polyethylene 0.935 g / cm ^3, ethylene-vinyl acetate copolymer, density 0.940~0.965g / cm ³ of high density polyethylene, agricultural claim 1 wherein the polypropylene resin is obtained by combination alone or two or more Polyolefin-based coating material.