JP2001334618A - Multilayered polyolefinic resin film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multilayered polyolefinic resin film having good heat sealability and excellent toughness and suitable for an agricultural or horticultural film. SOLUTION: The multilayered polyolefinic resin film has a layer (C) of a resin composition consisting of 100 pts.wt. of a resin (A) comprising low density polyethylene with a melt flow rate of 0.1-10 g/10 min and a density of 0.92-0.94 g/cm3 and 30-150 pts.wt. of a resin (B) comprising an ethylene/4-12C α-olefin copolymer with a melt flow rate of 0.1-10 g/10 min and a density of 0.91 g/cm3 or less as at least one outermost surface layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-sealing film which can be suitably used as an agricultural and horticultural film.

[0002]

2. Description of the Related Art Conventionally, polyvinyl chloride films and polyolefin resin films have been mainly used for greenhouses and tunnels for greenhouse horticulture. Is becoming the mainstream of agricultural and horticultural films. The polyolefin-based resin film is usually heat-sealed with each other, processed into a predetermined length, and then displayed in a house. In recent years, with the aging of farmers and the strengthening of agricultural competitiveness, the demand for long-term use of facility horticultural materials has increased,
Studies for long-term use are underway. 2. Description of the Related Art As an agricultural and horticultural film that can be used for a long period of time, a film whose durability is improved by making it thicker than a conventional film is known. However, such a film, due to its increased thickness, has a longer distance between the heating part of the heat sealing device and the heat sealing surface of the film during heat sealing, so that heat transfer to the heat sealing surface is slow. Become. Therefore, heat sealing of such a film involves:
A long heating time is required, and there is a problem that the processing time is long.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a multilayer film which is tough and has good heat sealing properties and is suitable as an agricultural and horticultural film.

[0004]

Means for Solving the Problems The present inventors have made a film comprising a resin composition containing a specific low-density polyethylene and a specific low-density ethylene / α-olefin copolymer in a specific blend ratio. Found that they had excellent heat sealability, and further improved the present invention.

That is, according to the present invention, as at least one outermost layer, 100 parts by weight of the following resin (A) and 30 to 1
Provided is a multilayer polyolefin resin film having a layer (C) of a resin composition comprising 50 parts by weight of the following resin (B). Resin (A): melt flow rate is 0.1 to 10 g / 1
0 minute, low density polyethylene resin having a density of 0.92 to 0.94 g / cm ³ or less Resin (B): melt flow rate of 0.1 to 10 g / 1
0 minutes, ethylene / density of 0.91 g / cm ³ or less
Α-olefin copolymer having 4 to 12 carbon atoms In the above constitution, the resin (A) has a melt flow rate of 0.1 to 2 g / 10 minutes, and the resin (B) has a melt flow rate of 0.1 to 4 g / 10. The film which is the component is a preferred embodiment of the multilayer film. The multilayer polyolefin-based resin film having the above structure is suitable as an agricultural and horticultural film. The present invention also provides a heat-sealing resin film comprising the above resin composition. A film in which the resin (A) has a melt flow rate of 0.1 to 2 g / 10 minutes and the resin (B) has a melt flow rate of 0.1 to 4 g / 10 minutes is a preferred embodiment of the heat-sealing resin film. .

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The polyolefin-based multilayer film of the present invention comprises, as at least one outermost layer, a resin composition comprising 100 parts by weight of the following resin (A) and 30 to 150 parts by weight of the following resin (B). (C). Resin (A): melt flow rate is 0.1 to 10 g / 1
0 minute, low density polyethylene resin having a density of 0.92 to 0.94 g / cm ³ or less Resin (B): melt flow rate of 0.1 to 10 g / 1
0 minutes, ethylene / density of 0.91 g / cm ³ or less
Α-olefin copolymer having 4 to 12 carbon atoms

The low-density polyethylene (A) used in the layer (C) has a melt flow rate (hereinafter sometimes referred to as MFR) of 0.1 to 10 g / 10 min, preferably 0.1 to 2 g. / 10 minutes. If the melt flow rate is too low, processability during film production may be poor, and if too high, the film strength may be poor.
From the viewpoint of the blocking property of the film, the density of the low-density polyethylene (A) measured according to JIS K7112 (hereinafter the same) is 0.92 to 0.94 g /.
cm ³ , preferably 0.92 to 0.93 g / cm ³
It is.

The α-olefin which is a copolymer component of the ethylene / α-olefin copolymer (B) used in the layer (C) has 4 to 12 carbon atoms. Examples of such α-olefins include propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene,
-Octene, 1-decene, 1-dodecene, 1-cyclohexene, cyclohexylethylene. The ethylene / α-olefin copolymer (B) may be a copolymer of ethylene and one type of α-olefin, or a copolymer of ethylene and two or more types of α-olefin. The content of the α-olefin monomer unit in the ethylene / α-olefin copolymer (the total amount when two or more α-olefins are used in combination) is from about 0.5 mol% to about 25 mol%. Preferably, from about 0.5 mol% to about 10
Mol% is more preferred, and about 1 mol% to about 7 mol% is even more preferred.

[0009] Ethylene / α-olefin copolymer (B)
Has a melt flow rate of 0.1 to 10 g / 10 min, and preferably 0.1 to 4 g / 10 min. If the melt flow rate is too low, the processability during film production may be poor, and if it is too high, the strength of the resulting laminated film may be poor. In the present invention, the density of the ethylene / α-olefin copolymer (B) is 0.9
1 g / cm ³ or less, and the lower the density is, the better the heat sealing property is.
The range is preferably 88 to 0.91 g / cm ³ .

[0010] Ethylene / α-olefin copolymer (B)
For example, using ethylene and an α-olefin having 4 to 12 carbon atoms in the presence of a solvent using a so-called single-site catalyst such as a complex catalyst of a transition metal such as palladium or nickel or a metallocene catalyst, or In the absence
It can be produced by a method of polymerizing in a gas phase / solid phase, liquid phase / solid phase or homogeneous liquid phase. The polymerization temperature is usually about 30 ° C. to about 300 ° C., the polymerization pressure is usually at or near atmospheric to about 3000 kg / cm ^2. For example, JP-A-6-9724, JP-A-6-136195,
JP-A-6-136196, JP-A-6-20705
No. 7 or the like, an ethylene / α-olefin is obtained by copolymerizing ethylene with an α-olefin having 4 to 12 carbon atoms in the presence of a so-called metallocene-based olefin polymerization catalyst containing a metallocene catalyst component. The copolymer (B) can be produced.

The blend ratio of the low-density polyethylene (A) and the ethylene / α-olefin copolymer (B) in the resin composition constituting the layer (C) depends on the heat sealability of the film and the processing during film production. In light of the properties, the ethylene / α-olefin copolymer (B) is preferably 30 to 150 parts by weight, more preferably 25 to 100 parts by weight, based on 100 parts by weight of the low-density polyethylene (A). Ethylene / α
-If the proportion of the olefin copolymer (B) is too low, the heat sealability of the film becomes insufficient, and if it is too high, the processability during the production of the film is impaired and the blocking property of the film deteriorates.

The environmental stress cracking resistance of the resin composition constituting the layer (C) (measured by a constant strain environmental stress cracking measurement method specified in JIS K6760-1981) is 100.
When the time is 0 hour or more, the multilayer film of the present invention becomes more excellent in detergent resistance and stain resistance. To make the environmental stress crack resistance of the resin composition constituting the (C) layer 1000 hours or more, for example, the low-density polyethylene (A) and the ethylene / α-olefin copolymer (B) in the resin composition are used. The blend ratio may be appropriately selected depending on the type of the ethylene / α-olefin copolymer to be used. For example, if the ethylene / α-olefin copolymer is ethylene / α-olefin copolymer,
In the case of a butene copolymer or an ethylene / pentene copolymer, the blend ratio is usually set to 10
The amount is preferably from 70 to 150 parts by weight based on 0 parts by weight. In the case of an α-olefin copolymer having ethylene / carbon number of 6 or more, the blending ratio of the low-density polyethylene 10
The amount is preferably 30 to 150 parts by weight with respect to 0 parts by weight.

The layer (C) preferably contains a fatty acid amide compound, organic fine particles, and / or inorganic fine particles from the viewpoints of anti-blocking property, dustproof property and friction resistance of the film.

Examples of the fatty acid amide compound include a saturated fatty acid amide, an unsaturated fatty acid amide and a bisfatty acid amide having a melting point of about 50 to about 200 ° C. Specific examples include behenic acid amide, stearic acid amide,
Palmitic acid amide, lauryl amide, erucic acid amide, oleic acid amide, methylenebisstearic acid amide, methylenebisbehenic acid amide, methylenebisoleic acid amide, ethylenebisstearic acid amide, ethylenebisbehenic acid amide, Examples include ethylenebisoleic acid amide, hexamethylenebisstearic acid amide, hexamethylenebisbehenic acid amide, hexamethylenebisoleic acid amide, and octamethylenebiserucic acid amide. When blending such a fatty acid amide,
The amount of the compound in the layer (C) depends on the resin components in the layer (C) (ie, low density polyethylene (A), ethylene / α).
About 0.01 parts by weight or more, preferably about 0.03 parts by weight, based on 100 parts by weight of the total
The amount is more preferably at least part by weight. Also, from an economic perspective,
It is preferably about 1 part by weight or less, more preferably about 0.5 part by weight or less.

Examples of the organic fine particles that can be contained in the layer (C) include crosslinked polymers having a particle size of about 0.5 μm to about 20 μm, and the refractive index of the resin component contained in the layer (C) is lower than that of the resin component. A closer one is preferred. For example, crosslinked beads such as polyethylene and polymethyl methacrylate are preferably used. When such organic fine particles are compounded, the compounding amount in the layer (C) is preferably about 0.1 part by weight or more, and more preferably about 0.3 part by weight, based on 100 parts by weight of the total of the resin components in the layer (C).
The amount is more preferably at least part by weight. Also, from an economic perspective,
It is preferably about 20 parts by weight or less, more preferably about 10 parts by weight or less, and particularly preferably about 5 parts by weight or less.

Examples of the inorganic fine particles that can be contained in the layer (C) include the inorganic infrared absorbers described below, and the compounding amount thereof is about 0.1 to 100 parts by weight of the resin component in the layer (C) in total. It is preferably at least 1 part by weight, more preferably at least about 0.3 part by weight. Also, it is preferably about 20 parts by weight or less, more preferably about 10 parts by weight or less, and particularly preferably about 5 parts by weight or less.

The polyolefin resin used for the resin layer other than the layer (C) of the multilayer film of the present invention includes, for example, α-olefin homopolymers such as polyethylene and polypropylene; ethylene / propylene copolymer, ethylene / butene -1 copolymer, ethylene / 4-methyl-1-
Pentene copolymer, ethylene / 1-hexene copolymer,
Ethylene / α- such as ethylene / 1-octene copolymer
Olefin copolymers containing α-olefin as a main component, ethylene / vinyl acetate copolymer, ethylene / acrylic acid copolymer, ethylene / methyl methacrylate copolymer, ethylene / vinyl acetate / methyl methacrylate copolymer Examples thereof include a polymer and an ethylene / polar vinyl monomer copolymer such as an ionomer resin.

Among these olefin resins, low-density polyethylene, ethylene / α-olefin copolymer,
Ethylene represented by ethylene / vinyl acetate copolymer
Polar vinyl monomer copolymer, etc., transparency, flexibility,
It is preferable because it is excellent in cost and the like. Among the ethylene / polar vinyl monomer copolymers, an ethylene / vinyl acetate copolymer having a vinyl acetate unit content of 30% by weight or less has excellent flexibility and suppresses wrinkles when a film is spread. It is preferable from the viewpoint of. Ethylene / α-olefin copolymer, especially ethylene / α having a narrow composition distribution and molecular weight distribution polymerized using a metallocene catalyst or the like
-An olefin copolymer is preferable because of its excellent mechanical strength and transparency.

Each layer of the multilayer film of the present invention can contain one or more infrared absorbers. The infrared absorbing agent is not particularly limited as long as it has a higher infrared absorbing ability than the resin material of each layer, and may be an inorganic infrared absorbing agent or an organic infrared absorbing agent. Examples of inorganic infrared absorbers include lithium aluminum composite hydroxides, composite hydroxides such as hydrotalcite compounds, oxides of metals such as magnesium oxide, calcium oxide, aluminum oxide, silicon oxide, and titanium oxide, and lithium hydroxide. , Magnesium hydroxide, calcium hydroxide, hydroxides such as aluminum hydroxide, magnesium carbonate, calcium carbonate, basic aluminum carbonate (for example,
Carbonates such as basic aluminum carbonate double salt described in JP-A-279131), sulfates such as potassium sulfate, magnesium sulfate, calcium sulfate, zinc sulfate and aluminum sulfate, lithium phosphate, sodium phosphate, potassium phosphate, calcium phosphate, and phosphoric acid Zirconium (for example, H-type zirconium phosphate described in JP-A-8-67774)
Such as phosphates, magnesium silicate, calcium silicate,
Silicates such as aluminum silicate and titanium silicate, aluminates such as sodium aluminate, potassium aluminate and calcium aluminate, aluminosilicates such as sodium aluminosilicate, potassium aluminosilicate and calcium aluminosilicate, kaolin, clay and talc Clay minerals, composite oxides and the like. Examples of the organic infrared absorber include polyacetal, polyvinyl alcohol and derivatives thereof, and ethylene / vinyl alcohol copolymer. Among these infrared absorbers, those having a density of about 3 g / cm ³ or less are preferable and the density is about 2.4 from the viewpoint of the recycling efficiency of the multilayer film.
g / cm ³ or less is more preferable. Further, from the viewpoint of infrared absorbing ability, an inorganic infrared absorbing agent is preferable.

When the infrared absorbing agent is an inorganic infrared absorbing agent, its refractive index is closer to the refractive index of the resin material used from the viewpoint of light transmittance, and it is broader from the viewpoint of heat insulation. It is preferable to have absorption performance in the wavelength range. From these viewpoints, hydrotalcite compounds,
Lithium-aluminum composite hydroxides, aluminosilicates, basic aluminum carbonate double salts and the like are preferred.

The hydrotalcite compound is represented by the following formula (I): M 2 ⁺ _{1 -x} Al ³⁺ _x (OH ⁻ ) ₂ (A ₁ ^{n −} ) _{x / n} · mH ₂ O (I) In the ^formula , M ²⁺ is a divalent metal ion, A ₁ ⁿ⁻ is an n-valent anion, and x, m and n are 0 <x <0.5,
The condition 0 ≦ m ≦ 2, 1 ≦ n is satisfied. ). As M ²⁺ , Mg ²⁺ , Ca ²⁺ , Zn ²⁺
And the like. The n-valent anion A ₁ ^n- is not particularly limited. For example, Cl ⁻ , Br ⁻ , I ⁻ , NO ₃ ⁻ , ClO ₄ ⁻ , S
_{^{O 4 2-, CO 3 2-,}} SiO 3 2-, HPO 4 3-, HBO 4 3-,
^{_{PO 4 3-, Fe (CN)}} 6 3-, Fe (CN) 6 4-, CH 3 C
Anions such as OO ⁻ , C ₆ H ₄ (OH) COO ⁻ , (COO) ₂ ²⁻ , terephthalate ion and naphthalene sulfonate ion, and polysilicate ion and polyphosphate ion described in JP-A-8-217912. Is mentioned. In particular,
For example, natural hydrotalcite or Alkamizer DH
Synthetic hydrotalcite such as T-4A (trade name, manufactured by Kyowa Chemical Industry) can be used. Further, calcium hydroxide or a calcium / aluminum composite hydroxide represented by the general formula: CaAl _x (OH) _{2 + 3x} may be used in combination with a hydrotalcite compound.

Examples of the lithium aluminum complex hydroxide, for example, the following formula disclosed in ^{JP-A-5-179052 (II): Li + (} Al 3+) 2 (OH -) 6 · (A 2 n- _{1 / n} · mH ₂ O (II) (wherein A ₂ ⁿ⁻ is an n-valent anion, m and n
Satisfies the condition of 0 ≦ m ≦ 3, 1 ≦ n). The n-valent anion A ₂ ^n- is not particularly limited, and examples thereof include the same anions as A ₁ ^n- in the compound of the formula (I).

The composite hydroxides other than the above two types include:
For example, alkaline earth metals, transition metals, Zn and Si
At least one element selected from the group consisting of
A composite hydroxide containing Li and Al and having a hydroxyl group is exemplified. Of the alkaline earth metals, magnesium and calcium are preferred. Further, among the transition metals, divalent or trivalent iron, cobalt, nickel, and manganese are preferable, and among them, iron is particularly preferable. The molar ratio of Al to Li (Al / Li) is usually 1.5 / 1 to 2.5 / 1.
And preferably from 1.8 / 1 to 2.5 / 1. The molar ratio (a) of an element selected from the group consisting of alkaline earth metals, transition metals, Zn and Si to 1 mol of Li element is usually 0 <a <1.5, preferably 0 <a <1.5. .1 ≦ a ≦ 1.4, more preferably 0.2 ≦ a ≦
1.2. The anion portion other than the hydroxyl group of the composite hydroxide is, for example, pyrosilicate ion, cyclosilicate ion, isosilicate ion, phyllosilicate ion, polysilicate ion such as tectosilicate ion, carbonate ion, halide ion, sulfate ion, Sulfite ion, nitrate ion, nitrite ion, phosphate ion, phosphite ion,
Hypophosphite ion, polyphosphate ion, aluminate ion, silicate ion, perchlorate ion, inorganic acid ions such as borate ^{_{ions, Fe (CN) 6 3-,}} Fe (CN) 6 4- , etc. anion And organic acid ions such as an ionic transition metal complex, an acetate ion, a benzoate ion, a formate ion, a terephthalate ion and an alkyl sulfonate ion. Among them, carbonate ion, halide ion, sulfate ion, phosphate ion, polyphosphate ion, silicate ion,
Polysilicate ions and perchlorate ions are preferred, and carbonate ions, polyphosphate ions, silicate ions and polysilicate ions are particularly preferred. Specific examples of such a composite hydroxide include Al, Li, Mg, and Al / Li
/ Mg = about 2.3 / 1 / 0.28 (molar ratio), a composite hydroxide (trade name LMA, manufactured by Fuji Chemical Industry), Al,
Contains Li and Si, and Al / Li / Si = about 2/1
/1.2 (molar ratio) (trade name: Fujilein LS, manufactured by Fuji Chemical Co., Ltd.).

[0024] WO97 / 00,828 disclosed the following formula ^{(III): [(Li +} (1-x) M 2+ x) (Al 3+) 2 (OH -) 6] 2 (Si y O (2y + ₁₎ ^2- ) _{(1 + x)} · mH ₂ O (III) (where M ²⁺ is a divalent metal ion, and m, x and y are 0 ≦ m <5, 0 ≦ x < 1, 2 ≦ y ≦ 4) and JP-A-8-21
No. 7912, the following formula (IV): [(Li ⁺ _(1-x) M ²⁺ _x ) (Al ³⁺ ) ₂ (OH ⁻ ) ₆ ] ₂ (A ⁿ⁻ ) _{2 (1 + x ) / n} · mH ₂ O (IV) (where M ²⁺ is a divalent metal ion, A ⁿ⁻ is an n-valent anion, and m, x and n are 0 ≦ m <5 , 0.
The compound represented by the following formula (01 ≦ x <1, 1 ≦ n) is a preferable example of the above-mentioned composite hydroxide. As M ²⁺ in the formulas (III) and (IV), Mg ²⁺ ,
Ca ²⁺ and Zn ²⁺ are exemplified.

Further, the following formula (V): mAl ₂ O ^3. (N / p) M _{2 / p} O.X.kH ₂ O (V) (where X is a carbonate group and M is an alkali metal Or an alkaline earth metal, p is equal to the valence of the metal M, and m, n and k are 0.3 ≦ m ≦ 1, 0.3 ≦ n ≦ 2, 0.5 ≦
The basic aluminum carbonate double salt represented by the formula (1) which satisfies the condition of k ≦ 4) is also one of preferred infrared absorbers. In the above formula (V), X represents sulfur oxyacid (sulfuric acid, sulfurous acid), nitrogen oxyacid (nitric acid, nitrous acid), hydrochloric acid,
Inorganic anions derived from oxyacids of chlorine (eg, perchloric acid), oxyacids of phosphorus (phosphoric acid, phosphorous acid, metaphosphoric acid), acetic acid, propionic acid, adipic acid, benzoic acid, phthalic acid, terephthalic acid Acid, maleic acid, fumaric acid,
A double salt containing an organic anion derived from succinic acid, p-oxybenzoic acid, salicylic acid, picric acid, toluenesulfonic acid or the like may be used in combination with the basic aluminum carbonate double salt. These double salts can be produced by the method disclosed in JP-A-9-279131.

When the above-mentioned composite hydroxide or basic aluminum carbonate double salt is used as an infrared absorbent, the average particle diameter is preferably about 5 μm or less, more preferably about 0.05 to about 3 μm, and more preferably about 0.1 to about 3 μm. More preferred is 1 to about 1 μm. The specific surface area measured by the BET method is 1 to 3.
0 m < ² > / g is preferred, and about 2 to about 20 m < ² > / g is more preferred.

When the multilayer film of the present invention is used for applications requiring a high degree of transparency, the refractive index of the infrared absorber is preferably close to the refractive index of the resin material used.
The refractive index measured by the method described in JIS K0062 is 1.
It is preferably 47 to 1.55, and 1.48 to 1.
54 is more preferable, and 1.49 to 1.53 is particularly preferable.

In order to improve the dispersibility of the infrared absorber in the multilayer film, the infrared absorber may be subjected to a surface treatment with a higher fatty acid or an alkali metal salt of a higher fatty acid. The amount of the infrared absorber in the multilayer film is 23 ° C.
Is appropriately set in consideration of the desired radiation transmission index of the multilayer film, the type of infrared absorber used, the layer configuration of the multilayer film, and the like. For example, when the above-mentioned composite hydroxide is used as an infrared absorbing agent, its compounding amount is about 6% by weight to about 13% by weight based on the total weight of the multilayer film.
Is preferred.

The radiation transmission index at 23 ° C. of the multilayer film is a measure of the heat retention when the film is used as a covering material for agricultural houses and the like, and has an effect on the growth of crops. It is determined by the measurement method used. The smaller the value of the radiation transmission index, the better the heat retention of the multilayer film. In the present invention, the multilayer film preferably has a radiation transmission index at 23 ° C. of 25 or less. When the multilayer film has a radiation transmission index of 25 or less, the heat retention is equal to or better than that of the conventional polyvinyl chloride film, and when used in a heated house, the heating cost can be reduced and the economic efficiency can be reduced. Contribute to the improvement of The radiation transmission index is preferably as close to zero as possible.
The following is more preferable, and 15 or less is still more preferable.

The radiation transmission index at 23 ° C. is measured by the following method. Using an infrared spectrophotometer (Perkin Elmer 1640 type FT-IR), a wave number of 40
An infrared absorption spectrum (transmission method) of the multilayer film is measured at a temperature of 23 ° C. in the range of 00 to 400 cm ⁻¹ to obtain a value of transmittance T (ν)% at a wave number ν. On the other hand, according to the equation (1) obtained from Planck's law, the blackbody radiation spectrum intensity e (ν) at the wave number ν at 23 ° C. is calculated. Here, the value obtained by multiplying the blackbody radiation spectrum intensity e (ν) by the transmittance T (ν) becomes the radiation transmission intensity f (ν) (Equation (2)). Radiation transmission intensity f (ν) integrated over a wave number range of 4000 to 400 cm ⁻¹ , radiation transmission energy F, black body radiation spectrum intensity e (ν) integrated over a wave number range of 4000 to 400 cm ^−1. Is defined as black body radiation energy E, and a radiation transmission index G = 100 × F / E is defined. In actual integration, the interval is divided into intervals of 2 cm -1 at wavenumber intervals, and calculation and integration are performed for each interval by trapezoidal approximation. e (ν) = (A / λ ⁵ ) / ｛exp (B / (λ × T)) ^-1 } (1) A = 2πhC ² = 3.74 × 10 ^-16 (W · m ² ) B = hC /K=0.01439 (mK) T (K) is an absolute temperature. λ (cm) is the wavelength. (The wave number ν is the reciprocal of the wavelength.) (H is Planck's constant, C is the speed of light, k is Boltzmann's constant.) F (ν) = e (ν) × T (ν) / 100 (2)

The multilayer film of the present invention can contain one or more light stabilizers. As the light stabilizer, a nickel complex light stabilizer can be used, but a hindered amine compound is preferable, and a hindered amine compound having a molecular weight of about 1500 or more is particularly preferable. Examples of the hindered amine compound include those having a structural formula described in JP-A-8-73667, and specific examples thereof include Tinuvin 622-LD (trade name) and Chimassorb 944.
-LD, Tinuvin 123 (all manufactured by Ciba Specialty Chemicals), Hostabin N30, VP Sanduv
or PR-31 (manufactured by Clariant) and Syasorb UV3529 (manufactured by Scitech). As a stabilizer containing a hindered amine compound, JP-A-63-163
No. 286448 (trade name: Tinuvin 492, Tinuvin 494, manufactured by Ciba-Geigy). When using a light stabilizer, the amount thereof is about 0.02 to about the total weight of the multilayer film from the viewpoint of the balance between the weather resistance improving effect and the suppression of blooming of the light stabilizer.
A range of about 5% by weight is preferred, about 0.1 to about 2% by weight is more preferred, and about 0.5 to about 2% by weight is even more preferred.
From the viewpoint of the weather resistance improving effect, it is more preferable that the light stabilizer is used in combination with the following ultraviolet absorber.

The multilayer film of the present invention can contain one or more UV absorbers. UV absorbers
It may be an organic compound or an inorganic compound. Examples of the organic UV absorber that can be used include a benzophenone UV absorber, a benzotriazole UV absorber, a benzoate UV absorber, a cyanoacrylate UV absorber, and the like. The inorganic ultraviolet absorber may contain a metal oxide such as cerium oxide or titanium oxide. For example, an ultraviolet absorber commercially available from Nippon Inorganic Chemical Industry Co., Ltd. under the trade name: Serigard can be used. . When an ultraviolet absorber is used, the amount thereof is about 0.0 with respect to the total weight of the multilayer film, from the viewpoint of the balance between the weather resistance improving effect and the suppression of blooming of the ultraviolet absorber.
A range from 1 to about 3% by weight is preferred, with about 0.05 to about 1% by weight being more preferred.

The multilayer film of the present invention may contain an antifogging agent for the purpose of imparting antifogging properties. When blending an antifogging agent, the blending amount is 0.1 to 4 with respect to the film weight.
% By weight, preferably 0.5 to 3% by weight, more preferably 1.5 to 3% by weight, and 2.2 to 2.
8% by weight is particularly preferred. The anti-fogging agent may be blended in any layer, and when blended in two or more layers, the blending amount may be the same or different for each layer.

The anti-fogging agent includes a solid type and a liquid type at normal temperature (23 ° C.). Examples of the solid anti-fogging agent include nonionic surfactants such as sorbitan monostearate. Sorbitan fatty acid ester surfactants such as sorbitan monopalmitate, sorbitan monobehenate, sorbitan monomontanate, glycerin monolaurate, glycerin monopalmitate, glycerin monostearate, diglycerin distearate, triglycerin monostearate Fatty acid ester surfactants such as glycerin and tetraglycerin monomontanate, polyethylene glycol surfactants such as polyethylene glycol monopalmitate and polyethylene glycol monostearate, and alkylphenol oxide addition of alkylphenol Of carboxylic acid, sorbitan / glycerin condensate and organic acid; polyoxyethylene alkylamine compounds such as polyoxyethylene (2 mol) stearylamine, polyoxyethylene (2 mol) laurylamine, polyoxyethylene (4 mol) stearylamine Polyoxyethylene (2 mol) stearylamine monostearate, polyoxyethylene (2 mol) stearylamine distearate, polyoxyethylene (4 mol) stearylamine monostearate, polyoxyethylene (4 mol) stearylamine distearate Polyoxyethylenes such as stearate, polyoxyethylene (8 mol) stearylamine monostearate, polyoxyethylene (2 mol) stearylamine monobehenate, polyoxyethylene (2 mol) laurylamine stearate Fatty acid esters of Chi alkylene alkyl amine compounds, polyoxyethylene (2
Mol) amine surfactants such as fatty acid amides of polyoxyethylene alkylamine compounds such as stearic acid amide;

Furthermore, if a liquid antifogging agent is mixed with the film at room temperature, deterioration of the light transmittance during storage and expansion can be avoided. Therefore, at least one type of liquid antifogging agent at room temperature is used. Mixing is effective. Examples of the antifogging agent which is liquid at ordinary temperature include glycerin monooleate, diglycerin monooleate, diglycerin sesquioleate, tetraglycerin monooleate, hexaglycerin monooleate, tetraglycerin trioleate, and hexaglycerin pentaoleate. Glycerin-based fatty acid esters such as ate, tetraglycerin monolaurate and hexaglycerin monolaurate, and sorbitan fatty acid esters such as sorbitan monooleate, sorbitan dioleate, and sorbitan monolaurate are also included. When compounding a liquid anti-fog agent into a film, the compounding amount is 0.2 to 3 with respect to the film weight.
% By weight, more preferably from 0.5 to 2% by weight.

The multilayer film of the present invention can contain an antifog. Examples of usable antifog agents include fluorine compounds having perfluoroalkyl groups and ω-hydrofluoroalkyl groups (especially fluorine-based surfactants), silicon compounds having alkylsiloxane groups (especially silicon-based surfactants), and the like. Is mentioned. When an antifog is included, its amount is from about 0.01 to about 3 to the weight of the film.
% Is preferred, with about 0.02 to about 1% being more preferred.

The multilayer film of the present invention may optionally contain
It can contain additives such as commonly used stabilizers (eg, antioxidants, heat stabilizers), antiblocking agents, lubricants, antistatic agents, pigments, and the like.

[0038] The multilayer film of the present invention can contain a near-infrared blocking agent. When a multilayer film containing a near-infrared ray blocking agent is used as a covering material for an agricultural house, it is possible to suppress a temperature drop inside the house during a hot daytime. As a near-infrared ray blocking agent, for example,
Organic compounds disclosed in JP-A-193522 (e.g., nitroso compounds and metal complexes thereof, cyanine compounds, squarylium compounds, thiol nickel complex compounds, phthalocyanine compounds, triallylmethane compounds, immonium compounds, diimonium Compounds, naphthoquinone compounds, anthraquinone compounds,
Amino compounds, aminium salt compounds) and inorganic compounds (eg, carbon black, antimony oxide, tin oxide doped with indium oxide, 4A and 5A in the periodic table)
Oxides or carbides of metals belonging to Group A or 6A,
Boron compound). A film containing a near-infrared ray blocking agent may be formed on the surface of the multilayer film of the present invention.
As a method of forming the coating, for example, a method of applying a coating liquid containing a near-infrared ray blocking agent and a water-soluble resin binder to a multilayer film and drying the coating liquid may be mentioned.

The multilayer film of the present invention can have an antifogging film on the surface so that the heat sealing property of the layer (C) is not impaired. A multilayer film having an antifogging film can exhibit excellent antifogging properties over a long period of time by extending the antifogging film so as to face the inside of the agricultural and horticultural house.

Examples of the anti-fogging film include a coating film of an inorganic oxide sol represented by colloidal silica and colloidal alumina, a coating film of a liquid containing a surfactant as a main component, and a liquid containing a hydrophilic resin as a main component. And a cast film containing a hydrophilic resin as a main component. Examples of the hydrophilic resin include polyvinyl alcohol, polysaccharides, and polyacrylic acid. The method for forming the anti-fogging film may be a coating method in which an anti-fogging agent-containing coating solution is applied to the surface on which the film is to be formed and dried, or the anti-fogging thin film is prepared in advance by a casting method or the like. Alternatively, a method of laminating this on a surface on which a film is formed may be used.

The thickness of the multilayer film of the present invention is preferably in the range of about 0.02 mm to about 0.3 mm, and more preferably about 0.05 mm, in view of film strength, film splicing workability and coating workability.
More preferably, from mm to about 0.25 mm. Further, the thickness of the C layer is preferably about 10% to about 30% of the thickness of the multilayer film from the viewpoints of moldability, transparency, film strength and the like, and about 1%.
5% to about 25% is more preferred.

The method for producing the multilayer film of the present invention is not particularly limited. The multilayer film of the present invention can be manufactured by the following method. Additives selected as needed to the resin material for each layer are mixed with a mixer such as a ribbon blender, a super mixer, a Banbury mixer, a single screw or twin screw extruder to obtain a resin composition. . Using the thus obtained resin composition for each layer, a multilayer film can be produced by a multilayer T-die film molding method, a multilayer inflation film molding method, or the like.

Since the multilayer film of the present invention is excellent in heat sealability, it is excellent in joint processing by heat sealing. Therefore, the multilayer film of the present invention can be suitably used as an agricultural and horticultural film used as a covering material for an agricultural and horticultural house or a tunnel.

The single-layer film made of the resin composition constituting the layer (C) of the multilayer film has excellent heat-sealing properties and is therefore useful as a heat-sealing resin film.

[0045]

According to the present invention, it is possible to provide a multi-layer film which is excellent in the processability of the splicing by heat sealing and which can be used for a long time as an agricultural and horticultural film.

[0046]

The present invention will now be described by way of examples, which should not be construed as limiting the invention. In addition, the test method in an Example and a comparative example is as follows.

(1) Heat Sealability In Examples 1 and 2 and Comparative Example 1, the inner layer surface and the outer layer surface of the film were heated under a pressurized condition for a predetermined time using a heat gradient heat sealer (manufactured by Toyo Seiki). And joined. Example 3,
In Comparative Example 4 and Comparative Example 2, the inner layer having no anti-fogging layer and the outer layer having the anti-fogging layer were heat-sealed. The pressing force at the time of heat sealing was 0.15 MPa,
The sealing temperature was 120 ° C. Autograph DSS100 (manufactured by Shimadzu Corporation)
And the peel strength (N / 1 cm width) was calculated. Based on the results, the heat sealability was evaluated according to the following criteria. Peel strength is 9.8 N / 1 cm width or more: Bonding between films is sufficient, and there is no practical problem. In the table, it was indicated by ○. Peel strength less than 9.8 N / 1 cm width:
Bonding between films is insufficient. In the table, it is indicated by x.

(2) Toughness Using a test piece punched with a JIS No. 1 dumbbell, a tensile test was performed using an Autograph DSS100 (manufactured by Shimadzu Corporation) to measure the tensile breaking strength (MPa). The average values in the MD and TD directions are shown.

(3) Environmental stress crack resistance The components contained in the outer layer shown in Table 1 were kneaded at 150 ° C. for 5 minutes using a Banbury mixer, and then granulated by a granulator to form a resin composition constituting the outer layer. The product was obtained in the form of a pellet. This was press-molded to obtain a sheet having a thickness of 3 mm.
Environmental stress crack resistance was measured in accordance with JIS K6760-1981 (constant strain environmental stress crack measurement method).
The reagent used was a 10% aqueous solution of Igepearl CO-630 (alkyl allyl polyethylene glycol manufactured by GAF). If the environmental stress crack resistance is 1000 hours or more, the detergent resistance and the stain resistance are excellent.

Examples 1 and 2 and Comparative Example 1 A three-layer tube (substrate) comprising a first layer, a third layer, and a second layer sandwiched between the first and third layers was prepared in the following manner. did. The first layer was the inner layer of the tube, the second layer was the middle layer of the tube, and the third layer was the outer layer of the tube. The composition of each layer is as described in Table 1. In the tables, the numerical value in parentheses after the symbol indicating the component is the percentage of the amount of the component with respect to the total amount of all components of the layer containing the component. First, the components contained in each layer were mixed at 150 ° C. using a Banbury mixer.
After kneading for 5 minutes, the mixture was granulated by a granulator to obtain a resin composition constituting each layer in the form of pellets. Table 1 shows each layer using resin composition pellets or resin pellets for each layer.
The three-layer tube was molded by a three-layer blown film molding machine so as to have the thickness described in (1).

The evaluation results of the film thus obtained are shown in Table 1. The films of Examples 1 and 2 were superior to the film of Comparative Example 1 in heat sealability and toughness. In addition, the film of the example,
It also had excellent heat retention, transparency, dust resistance and anti-blocking properties.

Examples 3 and 4 and Comparative Example 2 [Preparation of base material] A three-layer tube comprising a first layer, a third layer, and a second layer sandwiched between the first and third layers in the following manner. (Substrate) was produced. The first layer was the inner layer of the tube, the second layer was the middle layer of the tube, and the third layer was the outer layer of the tube. The composition of each layer is as described in Table 2. In the table,
The number in parentheses after a symbol indicating a component is the percentage of the amount of that component relative to the total amount of all components in the layer in which the component is included. First, the components contained in each layer were kneaded at 150 ° C. for 5 minutes using a Banbury mixer, and then granulated by a granulator to obtain a resin composition constituting each layer in the form of pellets. Using a resin composition pellet for each layer or a resin pellet, a three-layer tube was formed by a three-layer blown film forming machine such that each layer had the thickness shown in Table 2. [Formation of anti-fog layer] Alumina sol (Nissan Chemical Co., trade name: alumina sol 520 solid content 20%), colloidal silica (Nissan Chemical Co., trade name: Snowtex 20 solid content 20)
%), Sodium dodecylbenzenesulfonate (manufactured by Kao, trade name Neoperex F25), and sodium decanoate (manufactured by Nacalai Tesque) at 1.6%, 0.4%, 0.08% and 1.6%, respectively. Water was added so as to be 0.08% and mixed to prepare a coating liquid. A coating liquid is applied to the surface of the third layer of the base material that has been subjected to corona treatment in advance so that the solid content thickness is about 0.2 g / m ^2, and the coating solution is dried at room temperature to prevent defogging on the third layer. A layer was formed.

Table 2 shows the evaluation results of the films thus obtained. The films of Examples 3 and 4 were superior to the film of Comparative Example 2 in flexibility, transparency, and toughness. In addition, the film of the example,
It also had excellent heat retention, transparency, dust resistance and anti-blocking properties.

[0054]

[Table 1]

[0055]

[Table 2]

A1: Low density polyethylene (trade name: Sumikacene F208-1; MFR: 1.4 g / 10 min; density: 0.923 g / cm ³ ; manufactured by Sumitomo Chemical Co., Ltd.) A2: Ethylene / hexene copolymer (trade name) Name: Sumikacene EFV401; MFR: 4.1 g / 10 minutes; density 0.904 g / cm ³ ; manufactured by Sumitomo Chemical Co., Ltd. A3: Ethylene / vinyl acetate copolymer (trade name: Evatate H2031; vinyl acetate unit content: 19% by weight; MFR: 1.5 g / 10 min; Density: 0.940 g /
cm ³ ; manufactured by Sumitomo Chemical Co., Ltd.) A4: Ethylene / vinyl acetate copolymer (trade name: Evatate D2011; vinyl acetate unit content: 5% by weight; M)
FR: 1.8 g / 10 min; Density: 0.922 g / c
m ^3; manufactured by Sumitomo Chemical Co., Ltd.) E1: Trade name: Sumilizer BP76; manufactured by Sumitomo Chemical Co., E2: trade name: Irgafos P168; Ciba Geigy F1: hindered amine compound (trade name: Chimassorb 944LD; manufactured by Ciba-Geigy) F2: hindered amine compound (Product name: Tinuvin 6
G1: Trade name: Sumisorb 130; Sumitomo Chemical Co., Ltd. H1: Diglycerin sesquioleate H2: Mixture in which the weight ratio of monoglycerin monostearate / diglycerin sesquistearate = 3/7 I1: Fluorine-based Surfactant (trade name: Unidyne DS4)
03; manufactured by Daikin Industries) J1: Lithium aluminum composite hydroxide (trade name: Mis @ Kalac; manufactured by Mizusawa Chemical Industry) K1: Fatty acid amide compound ethylenebisoleic acid amide K2: Fatty acid amide compound erucic acid amide

Continuation of front page (72) Inventor Hitoshi Nanbu 2-10-1, Tsukahara, Takatsuki-shi, Osaka F-term in Sumika Plastics Co., Ltd. (Reference) 2B024 DA04 DB01 DB07 2B029 EB03 EC02 EC09 EC14 EC20 4F100 AK06A AK06C AK08A AK08C AK68B AT00B BA03 BA06 BA10A BA10C BA15 EH20 EJ37 GB01 JA06A JA06C JA13A JA13C JK01 JK13 JK17 JL06 JN01 YY00A YY00C 4J002 BB03W BB05X GA01

Claims (5)

[Claims] 1. A resin composition layer (C) comprising 100 parts by weight of the following resin (A) and 30 to 150 parts by weight of the following resin (B) as at least one outermost layer. Multi-layer polyolefin resin film. Resin (A): melt flow rate is 0.1 to 10 g / 1
0 minute, low density polyethylene resin having a density of 0.92 to 0.94 g / cm ³ or less Resin (B): melt flow rate of 0.1 to 10 g / 1
0 minutes, ethylene / density of 0.91 g / cm ³ or less
Α-olefin copolymer having 4 to 12 carbon atoms 2. A resin (A) having a melt flow rate of 0.1
2. The resin (B) has a melt flow rate of 0.1 to 4 g / 10 minutes.
The multilayer polyolefin-based resin film according to the above. 3. The multilayer polyolefin resin film according to claim 1, which is an agricultural and horticultural film. 4. A heat-sealing resin film comprising a resin composition comprising the following resin (A) 100 parts by weight and the following resin (B) 30 to 150 parts by weight. Resin (A): melt flow rate is 0.1 to 10 g / 1
0 minute, low density polyethylene resin having a density of 0.92 to 0.94 g / cm ³ or less Resin (B): melt flow rate of 0.1 to 10 g / 1
0 minutes, ethylene / density of 0.91 g / cm ³ or less
Α-olefin copolymer having 4 to 12 carbon atoms 5. A resin (A) having a melt flow rate of 0.1
The melt flow rate of the resin (B) is 0.1 to 4 g / 10 minutes, and the melt flow rate of the resin (B) is 0.1 to 4 g / 10 minutes.
The heat-sealable resin film according to the above.