JPH08143718A - Agricultural polyolefin resin film - Google Patents

Abstract

PURPOSE: To prepare an agricultural polyolefin resin film excellent in antifogging properties and their persistence in addition to heat-insulation properties. CONSTITUTION: This film is made of a resin composition containing a major amount of ethylene polymer of a density of 0.89-0.935g/cm<3> , 5-30wt.% ethylene/ propylene elastic copolymer of a density of 0.87g/cm<3> or less, 0.5-2.0wt.% at least one antifogging agent and 0.5-20wt.% inorganic filler. A desirable example of this film is the one wherein the ethylene/propylene elastic copolymer has a Mooney viscosity (ML1+4 , 100 deg.C) of 20-70 and a propylene unit content of 22-50wt.%, the ethylene polymer is an ethylene/α-olefin copolymer of a melt index of 0.5-10g/10min, and the inorganic filler is based on a hydrotalcite or an aluminum lithium complex hydroxide salt.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an agricultural polyolefin resin film. More specifically, the present invention relates to an agricultural polyolefin resin film having excellent anti-fogging property and anti-fogging durability while having excellent heat retention.

[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 inferior in workability and dust resistance due to the plasticizer contained in the film bleeding out on the surface and causing stickiness, and various problems such as generation of harmful gas at the time of incineration and disposal are emerging. Therefore, a polyolefin resin film having improved heat retention, transparency, toughness, anti-fog property, house adhesion, etc., which are the drawbacks of agricultural plastics and agricultural vinegar, is being developed and put on the market.

Since the polyolefin resin film does not contain a plasticizer in the film and has a stable chemical structure, the light transmittance is almost the same even during long-term use and no harmful gas is generated even when incinerated. It has the advantage of not having
It had a drawback that the heat retaining property was inferior to that of agricultural products. Generally, the heat retaining property of the coating film in greenhouses and houses is a property that prevents the temperature inside the house from falling at night, and the heat absorbed in the ground inside the house by sunlight during the day radiates from the ground at night. The temperature inside the house is kept high by being radiated as a line, but if the transmittance of the radiation from the ground of the coating film is high, the radiation from the ground will be dissipated outside the house and The ground temperature of the house decreases, and as a result, the temperature inside the house cannot be kept higher than the outside air. Therefore, the heat retaining property of the coating film depends on whether the radiation is absorbed or reflected, and the higher the ratio, the better. In order to improve the heat retention of the polyolefin-based resin film, Japanese Patent Publication No. 47-9260, phosphate, Japanese Patent Publication No. 47-13853, silicon oxide, JP-A-49-105843, anhydrous aluminosilicate, Japanese Patent Application Laid-Open No. 52-32938 discloses dehydrated kaolinite, Japanese Patent Publication No. 3-50791 discloses a magnesium compound, and Japanese Patent Publication No. 62-3174 discloses a technique for adding an inorganic filler such as hydrotalcites. Further, JP-A-61-81446 discloses a water-absorbent resin, and JP-A-55-118941 discloses an addition technique of ethylene / vinyl alcohol copolymer and the like. In particular, the use of the above-mentioned inorganic filler as a heat retaining agent is simple and effective in heat retaining property with less cost constraint, so that it is now widely used.

In order to impart anti-fogging property, a method of kneading an anti-fogging agent into a film or applying an anti-fogging coating agent on the surface has been taken, but the anti-fogging agent is kneaded. The method is far more cost effective and is widely adopted.
In general, when using an agricultural film that is not provided with anti-fog properties as a coating material for a house or a tunnel, water in the soil evaporates to form water droplets that condense on the inner surface of the film due to the temperature difference between the inside and outside of the coating film, The water drops cause the film to become cloudy and reflect a portion of the sun's rays, so that the amount of light rays passing through the film is reduced, so that the effect of increasing the temperature in the house or tunnel is reduced. Further, the water droplets condensed on the inner surface of the film have a bad influence such as falling on the cultivated crops, damaging the shoots and seedlings, and causing a disease. Against these adverse effects, a film in which a surfactant having an action of an antifogging agent is kneaded is used, and this antifogging agent prevents evaporated water from staying as a water drop on the film surface, It has the function of spreading water droplets in a film shape and causing them to flow down along the inner surface of the film. Farm bi
Since it contains a large amount of a plasticizer having a polar group, the antifogging property is likely to last, but since the polyolefin resin film has almost no polar group, it is difficult to obtain the antifogging property. Further, in the case of a polyolefin resin film, an inorganic filler is added as a heat retaining agent in order to improve the heat retaining property, but this heat retaining agent adsorbs and retains the antifogging agent, and further antifogging sustainability is obtained. It had the drawback of being difficult.

In view of the above situation, the present invention adds a specific ethylene-propylene elastic copolymer to a resin composition containing an ethylene polymer as a main component, which contains an antifogging agent to which an inorganic filler is added as a heat retaining agent. By doing so, while having heat retention, it has excellent antifogging performance with a small amount of antifogging agent,
In addition, it is possible to provide an agricultural polyolefin resin film having excellent antifogging durability.

[0006]

The present invention has the following constitution. (1) The ethylene polymer of a density 0.89~0.935g / cm ³ was used as a main component, density 0.87 g / cm ³ or less of ethylene - propylene elastic copolymer 5 to 30 wt%, of one or more anti-fogging agent 0.5 A polyolefin resin film for agriculture comprising a resin composition containing ˜2.0% by weight and an inorganic heat retaining agent in an amount of 1 to 20% by weight. (2) The ethylene-propylene elastic copolymer has a Mooney viscosity of 20 to 70 ML _{1 + 4} (100 ° C.) and a propylene unit content of 22 to
The agricultural polyolefin resin film according to the above item 1, which is 50% by weight. (3) The ethylene polymer has a melt index of 0.5 to 1
The polyolefin resin film for agriculture according to item 1 above, which is an ethylene-α-olefin copolymer at 0 g / 10 minutes. (4) The inorganic heat insulating material according to claim 1, wherein the main component is either a hydrotalcite compound represented by the following general formula (1) or an aluminum-lithium composite hydroxide salt represented by the general formula (2). Polyolefin resin film for agriculture. General formula (1) M ²⁺ _1-X Al _X (OH) ₂ (A ⁿ⁻ ) _{X / n} · mH ₂ O (wherein M ²⁺ is 2 selected from the group consisting of magnesium, calcium and zinc) Represents a valent metal ion, A ^n- represents an n-valent anion, _X and m are as follows, 0 < _X <
0.5, 0 ≦ m ≦ 2 is satisfied. ) General formula (2) [Al ₂ Li (OH) ₆ ] _n X · mH ₂ 0 (wherein, X is an inorganic or organic anion,
n is the valence of the anion X, and m is 3 or less. )

The present invention will be described in detail below. As the ethylene-based polymer, ethylene homopolymer, polyethylene,
Ethylene-α-olefin inelastic copolymer, ethylene-
Examples of the vinyl acetate copolymer, ethylene-acrylate copolymer, ethylene-methacrylate copolymer and the like, the ethylene-based polymer in the present invention, the density, from the viewpoint of the transparency, flexibility and adhesion described above. 0.89-0.
935 g / cm ³ ethylene homopolymer or ethylene and α-olefin having 4 to 8 carbon atoms, specifically 1-butene, 1-
Pentene, 1-hexene, 4-methyl-1-pentene,
An ethylene-α-olefin copolymer or the like which is a copolymer with 1-octene is used. Particularly when transparency is required, the ethylene-1-hexene copolymer is desirable because it has excellent compatibility with the ethylene-propylene elastic copolymer.

The melt index (MI) of these ethylene-based polymers is not limited, but is 0.5 to 2.0 when the film forming method is an inflation method.
If it is about g / 10 minutes, or in the case of the T-die method, 1.
Generally, those having an MI of about 0 to 10 g / 10 minutes are used, but those having a low MI within the range not impairing the film forming property are desirable in order to improve the film strength.

The ethylene-propylene elastic copolymer used in the present invention is vulcanized by introducing an unsaturated bond of an ethylene-propylene copolymer vulcanized with peroxide and a third component such as dicyclopentadiene or ethylidene norbornene. And ethylene propylene terpolymer. The Mooney viscosity of the ethylene-propylene elastic copolymer is not limited, but is 20 to 70 ML _{1 + 4} (100
℃), the propylene unit content is 20 ~ 5
About 0% by weight is preferably used. Tendency Mooney viscosity 20 mL 1 + ₄ is reduced film strength (100 ° C.) of less than one, for those exceeding 70ML 1 + ₄ a (100 ° C.) is the inferior film processability, haze of the surface also decreases It is in.

In the present invention, the blending amount of the ethylene-propylene elastic copolymer is preferably 5 to 30% by weight. When the blending amount is less than 5% by weight, the effect of maintaining the antifogging property of the obtained film is not recognized, and when the amount of the antifogging agent is increased, the amount transferred to the surface immediately after film formation is large. Poor transparency and adhesion due to whitening become severe. On the other hand, when it exceeds 30% by weight, the amount of migration to the surface over time increases and the durability of antifogging property decreases.

Examples of the antifogging agent used in the present invention include nonionic surfactants, cationic surfactants, anionic surfactants and amphoteric surfactants, which may be used alone or in combination. Among them, a nonionic surfactant having a relatively high compatibility with the ethylene polymer and the ethylene-propylene elastic copolymer is preferably used.
A cationic surfactant, an anionic surfactant and the like are also used in combination for the purpose of modifying the antifogging property at the initial stage and at low temperature.

Examples of nonionic surfactants include polyethylene glycol ethers such as polyethylene glycol nonylphenyl ether and polyethylene glycol stearyl ether, polyethylene glycol stearates, polyethylene glycol carboxylic acid esters such as polyethylene glycol dilaurate, and glycerin monostearate. Partial carboxylic acid esters of polyhydric alcohols such as oleate, sorbitan monopalmitate, sorbitan tristearate, polyoxyethylene derivatives of sorbitan monostearate, polycarboxylic acid derivatives of sorbitan monolaurate, etc. Polyoxyethylene derivative of acid ester, N, N-di- (hydroxyethyl) -laurylamide, N- (2-
Examples thereof include amide derivatives such as hydroxypropyl) -stearoamide.

As the cationic surfactant, lauryl trimethyl ammonium chloride, N, N-dimethyl-N- (hydroxyethyl) -3- (stearoamide)
-Quaternary ammonium salts such as propylammonium nitrate, 2-octadecyl- (hydroxyethyl)-
Examples thereof include imidazoline derivatives such as 2-imidazoline, N, N-diethyl- (stearoamide) -methylamine hydrochloride, amines such as polyoxyethylene stearylamine, and the like.

Examples of the anionic surfactant include phosphoric acid esters such as sodium lauryl phosphate and sodium polyoxyethylene-lauryl phosphate, sulfuric acid esters such as sodium lauryl sulfate and sodium salt of sulfated oleic acid, and stearyl sulfone. Examples thereof include sulfonic acid salts such as sodium acid salt, dodecylbenzenesulfonic acid triethanolamine salt, and sodium salt of dioctylsulfosuccinate.

The amount of the antifogging agent added to the agricultural polyolefin resin film of the present invention is preferably in the range of 0.5 to 2% by weight, and if it is less than 0.5% by weight, the antifogging property sustaining effect is not sufficient, and If it exceeds 2% by weight, the migration of the antifogging agent to the surface becomes remarkable immediately after the film formation, and there is a problem that transparency is lowered due to whitening.

The inorganic filler of the present invention may be any one as long as it is added to the polyolefin resin film and exhibits absorption / reflection in the far infrared region. Specifically, silicon oxide, magnesium silicate, aluminum silicate, calcium silicate and other silicate compounds, calcium aluminosilicate, sodium aluminosilicate, aluminosilicate compounds such as potassium aluminosilicate, alumina, sodium aluminate, potassium aluminate, calcium aluminate. Aluminic acid compounds such as calcium carbonate, general formula
Examples thereof include one or more inorganic fillers selected from the group consisting of hydrotalcites represented by (1) and lithium-aluminum composite hydroxide salts represented by the general formula (2). General formula (1) M ²⁺ _1-X Al _X (OH) ₂ (A ⁿ⁻ ) _{X / n} · mH ₂ O (wherein M ²⁺ is 2 selected from the group consisting of magnesium, calcium and zinc) Represents a valent metal ion, A ^n- represents an n-valent anion, _X and m are as follows, 0 < _X <
0.5, 0 ≦ m ≦ 2 is satisfied. ) General formula (2) [Al ₂ Li (OH) ₆ ] _n X · mH ₂ 0 (wherein, X is an inorganic or organic anion,
n is the valence of the anion X, and m is 3 or less. )

The transparency of the polyolefin resin film depends on the type of the inorganic filler, and the closer the refractive index of the polyolefin resin and the refractive index of the inorganic filler are, the more the transparency is improved. In order to maintain transparency,
The hydrotalcites represented by the above general formulas (1) and (2), lithium-aluminum complex hydroxide salts, and the like are preferably used.

When the inorganic filler is added to the agricultural polyolefin resin film of the present invention, the addition rate is 0.5.
The range is preferably from 20 to 20% by weight, and if it is less than 0.5% by weight, the heat retaining property is insufficient and the workability is deteriorated when the films adhere to each other and are spread on the house. On the other hand, if it exceeds 20% by weight, the processability of the film is poor and the physical properties of the film are poor, which is not preferable.

In the production of the agricultural polyolefin resin film according to the present invention, a weather resistance improver such as an antifog agent, an antioxidant, an ultraviolet absorber and a light stabilizer is prepared according to a conventional method.
You may add various additives, such as an antiblocking agent and a slip agent.

The agricultural polyolefin resin film of the present invention is molded by a known molding method such as an inflation method or a T-die method, and the thickness of the film generally varies depending on the place of use, service life, etc. 0.05 to 0.20 mm
The thing of a grade is used suitably. In addition, the agricultural polyolefin resin film of the present invention may be a multilayer agricultural polyolefin resin film having two or more layers by laminating a resin layer on at least one surface by a known technique such as coextrusion or lamination, if necessary. Further, a dustproof coating agent or the like may be applied and dried to form a coating film on the surface.

[0021]

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 density and melt index (MI) shown in Examples and Comparative Examples are values measured by the method specified in JIS-K-7210. The antifogging property was evaluated by the initial antifogging test and the accelerated antifogging test. In the initial anti-fogging test, boiling water was put in a beaker, the beaker mouth was covered with an evaluation sample, and the presence or absence of anti-fogging property after 5 minutes was judged by ○, Δ, and ×. ◯: No water droplets Δ: Some water droplets were generated ×: Many water droplets adhered Further, in the accelerated anti-fogging test, an angle of 1 was set on the water tank at a water temperature of 40 ° C.
Paste the sample with a 0 degree inclination (8 hours / 1
Day) Evaluation was carried out. Antifogging durability was judged by the number of days until the antifogging property was maintained. Regarding spreading workability, A (excellent), B (slightly problematic but practical use possible), and C (not practical use possible) are available for the problem of poor workability due to stickiness at the time of expansion to the house. It was evaluated in 3 ranks.

Examples 1 to 4 An ethylene-1-hexene copolymer (MI = 2.5, ρ = 0.92) was prepared using a 65φ extruder equipped with a 600 mm wide T-die.
Ethylene-propylene elastic copolymer (Moonee viscosity 24ML _{1 + 4} (100 ° C.), propylene content 26% by weight) is 15% by weight, polyglycerin monostearate and glycerin distearate are each 0.25, 0.5, 0.75, 1.0
A resin composition comprising 5% by weight of a hydrotalcite compound (Kyowa Chemical Co., Ltd., trade name: DHT-4A), which is an inorganic heat retaining agent, has a die temperature of 220 ° C. and a discharge rate of 40 kg / h.
A film having a thickness of 100 μ was obtained by forming the film under the condition of r.

Examples 5 to 6 The same as Example 1 except that the blending amounts of polyglycerin monostearate and glycerin distearate were 0.5% by weight and the blending amount of the hydrotalcite compound was 10 and 20% by weight, respectively. It was carried out.

Examples 7 to 8 Polyglycerin monostearate and glycerin distearate were blended in amounts of 0.5% by weight, and ethylene-propylene elastic copolymer pellets (Moonie viscosity 24 ML _{1 +4} (100
C.) and propylene content 26% by weight) except that the compounding amounts were 5 and 30% by weight.

Example 9 Polyglycerin monostearate and glycerin distearate were each mixed in an amount of 0.5% by weight, and a lithium / aluminum complex hydroxide salt (manufactured by Mizusawa Chemical Co., Ltd.) was used in place of the hydrotalcite compound. (Name: Mizucarac) The same procedure as in Example 1 was performed except that 5% by weight was used.

Examples 10-11 Polyglycerin monostearate and glycerin distearate were mixed in amounts of 0.5% by weight, respectively, and ethylene-1
-Ethylene homopolymer instead of hexene copolymer (M
I = 2.5, ρ = 0.92), ethylene-butene copolymer (M
It carried out like Example 1 except having used I = 4.0 and p = 0.935).

Comparative Examples 1 to 3 An ethylene-1-hexene copolymer (MI = 2.5, ρ = 0.92) was prepared using a 65φ extruder equipped with a 600 mm wide T-die.
A resin composition containing 0.5%, 0.75, and 1.0% by weight of polyglycerin monostearate and glycerin distearate, respectively, as a main component, and a die temperature of 220 ° C., and an ejection amount of 40
The film was formed under the condition of kg / hr to obtain a film having a thickness of 100μ.

Comparative Examples 4 to 6 Ethylene-1-hexene copolymer (MI = 2.5, ρ = 0.9
2) as a main component, polyglycerin monostearate and glycerin distearate 0.5, 0.75, 1.0% by weight, respectively, hydrotalcite compound (Kyowa Chemical Co., Ltd.,
A resin composition containing 5% by weight of a product name: DHT-4A) was formed into a film in the same manner as in Comparative Example 1.

Comparative Examples 7 to 9 Ethylene-1-hexene copolymer (MI = 2.5, ρ = 0.9
2) as a main component, ethylene-propylene elastic copolymer 1
A resin composition containing 5% by weight, polyglycerin monostearate and glycerin distearate of 0.5, 0.75 and 1.0% by weight, respectively, was formed into a film in the same manner as in Comparative Example 1.

Comparative Example 10 The procedure of Example 9 was repeated except that the ethylene-propylene elastic copolymer was not used.

[0031]

EFFECT OF THE INVENTION The agricultural polyolefin resin film of the present invention comprises an ethylene polymer, an antifogging agent and an inorganic filler, and further, an ethylene-propylene elastic copolymer is added thereto to add an inorganic filler. It has become possible to eliminate the deterioration of the anti-fog developing property and the decrease of the anti-fog persistence. As a result, it is possible to provide an antifog property with a small amount of antifog property, which is economically advantageous, and it is possible to provide an agricultural polyolefin resin film having long-term antifog property by improving antifog durability. Therefore, it can be suitably used as an agricultural covering material for long-term durable houses, tunnels and the like.

[0032]

[Table 1]

[0033]

[Table 2]

[0034]

[Table 3]

[0035]

[Table 4]

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location C08L 23/16 LCY

Claims (4)

[Claims] [Claim 1] as a main component ethylene polymer having a density 0.89~0.935g / cm ^3, density of 0.87 g / cm ³ or less of ethylene - propylene elastic copolymer 5 to 30 wt%, of one or more anti-fogging Agent 0.5 ~
An agricultural polyolefin resin film comprising a resin composition containing 2.0% by weight and 0.5 to 20% by weight of an inorganic filler. 2. The agricultural polyolefin resin film according to claim 1, wherein the ethylene-propylene elastic copolymer has a Mooney viscosity of 20 to 70 ML _{1 + 4} (100 ° C.) and a propylene unit content of 22 to 50% by weight. 3. An ethylene polymer having a melt index
The agricultural polyolefin resin film according to claim 1, which is an ethylene-α-olefin copolymer of 0.5 to 10 g / 10 min. 4. The inorganic filler mainly contains either hydrotalcites represented by the following general formula (1) or aluminum-lithium composite hydroxide salt represented by the general formula (2). Agricultural polyolefin resin film. General formula (1) M ²⁺ _1-X Al _X (OH) ₂ (A ⁿ⁻ ) _{X / n} · mH ₂ O (wherein M ²⁺ is 2 selected from the group consisting of magnesium, calcium and zinc) Represents a valent metal ion, A ^n- represents an n-valent anion, _X and m are as follows, 0 < _X <
0.5, 0 ≦ m ≦ 2 is satisfied. ) General formula (2) [Al ₂ Li (OH) ₆ ] _n X · mH ₂ 0 (wherein, X is an inorganic or organic anion,
n is the valence of the anion X, and m is 3 or less. )