JP5224840B2 - Gas permeable film - Google Patents

Description

  The present invention relates to a gas permeable film excellent in transparency and gas permeability. More specifically, the present invention relates to a gas permeable film containing a polypropylene copolymer, which is suitable for freshness-maintaining packaging of fruits and vegetables and flowers.

  In general, polyolefin resin films are widely used as various packaging materials such as foods, daily necessities, and industrial products due to their excellent moldability, transparency, and mechanical properties. However, when vegetables and fruits and flowers are sealed and wrapped in a film, the transpiration and respiration rate of the water are reduced at an early stage, so that a certain freshness maintaining effect can be obtained. When the concentration increases, there is a problem that the rot due to anaerobic breathing starts and the freshness rapidly decreases.

  For this reason, low density polyethylene (LDPE and LLDPE) films with relatively high gas permeability are often used for packaging fruits and vegetables, but lack transparency and rigidity compared to polypropylene and polystyrene films. There is a problem. In addition, polystyrene film has transparency and rigidity, and its gas permeability is relatively high, so it is still used for packaging for the same purpose, but it is easy to tear because it has low elongation compared to polypropylene film and low density polyethylene film. There is also a problem that the seal strength is low.

  On the other hand, since a polypropylene film is also excellent in transparency and rigidity, for example, a biaxially stretched polypropylene film imparted with an antifogging property is used for packaging fruits and vegetables and flowers (see, for example, Patent Document 1). However, since the polypropylene film has a lower gas permeability than a low density polyethylene film or a polystyrene film, it has poor freshness retention when sealing fruits and vegetables and flowers.

  Therefore, a technique for hermetically wrapping fruits and vegetables with a film having gas permeability by opening a minute hole has been proposed (see, for example, Patent Document 2). However, in this method, equipment and processing costs for punching are generated, and in addition to the problem that the productivity of the film is reduced, contaminants may enter from the outside through the hole. Furthermore, since such a film also permeates water vapor, the freshness of a package such as fruits and vegetables is significantly reduced.

  Further, a packaging resin laminated film is proposed in which an intermediate layer made of a polypropylene resin blended with a thermoplastic elastomer, an outer layer made of a polyolefin resin, and an inner layer are laminated (for example, see Patent Document 3). However, in such a resin laminated film for packaging, by including a thermoplastic elastomer that allows gas to easily permeate, there is some improvement in gas permeability, but still a sufficient gas permeability cannot be obtained. Since the dispersibility of the thermoplastic elastomer in the polypropylene resin is poor, there is a variation in transparency and gas permeability even with the same film.

A gas permeable film made of polypropylene and an ethylene-1-octene copolymer has been proposed (see, for example, Patent Document 4). However, such a gas permeable film has poor dispersibility of the ethylene-1-octene copolymer, which is easily permeable to gas in the film. Furthermore, there is still room for improvement in gas permeability and transparency.
JP 2003-291282 A JP 2004-16134 A JP 2005-238731 A JP 2006-299229 A

  An object of the present invention is to provide a gas permeable film excellent in transparency and gas permeability.

  As a result of intensive studies to solve the above problems, the present inventors have found that excellent transparency and gas permeability can be exhibited by using a specific propylene / ethylene block copolymer, and complete the present invention. It came to.

That is, this invention is specified by the matter described below.
The gas permeable film of the present invention has a melt flow rate (ASTM D 1238, 230 ° C., load 2.16 kg) in a range of 1 to 10 g / 10 min, and is measured by a differential scanning calorimeter (DSC). Melting | fusing point exists in the range of 145-170 degreeC, and the following (1)-(3) satisfy | fills the part ( _Dinsol ) 90-70 weight% insoluble in room temperature n-decane and the following (4)-(6) is satisfy | filled. A propylene / ethylene block copolymer (A) composed of 10 to 30% by weight of a portion soluble in room temperature n-decane (D _sol ) is included.

(1) The molecular weight distribution (Mw / Mn) determined from GPC (gel permeation chromatography) of D _insol is 1.0 to 3.5.
(2) The content of the skeleton derived from ethylene in D _insol is less than 0.5 mol%. (3) The sum of the 2,1-insertion bond amount and 1,3-insertion bond amount of propylene in D _insol is 0.2 mol% or less (4) The molecular weight distribution (Mw / Mn) determined from GPC of D _sol is 1.0 to 3.5.
(5) The intrinsic viscosity [η] in 135 ° C. decalin of D _sol is 1.5 to 4.5 dl / g
(6) The content of the skeleton derived from ethylene in D _sol is 15 mol% or more and less than 45 mol%.

The propylene / ethylene block copolymer (A) is preferably polymerized in the presence of a metallocene catalyst.
The gas permeable film of the present invention preferably contains an ethylene / α-olefin random copolymer (B) in addition to the propylene / ethylene block copolymer (A).

  Further, the content of the ethylene / α-olefin random copolymer (B) is more than 0 to 40% by weight (provided that the content of the propylene / ethylene block copolymer (A) + ethylene / α-olefin random copolymer). It is preferable that the content of the polymer (B) = 100 wt%).

The α-olefin of the ethylene / α-olefin random copolymer (B) is preferably 1-octene.
The gas permeable film of the present invention is preferably stretched in the biaxial direction.

Moreover, the gas permeable laminated film of the present invention is preferably formed by laminating a layer containing a propylene-based polymer (C) on at least one side of the gas permeable film.
Moreover, it is preferable that the thickness of the layer containing the propylene polymer (C) of the gas permeable laminated film of the present invention is in the range of 1 to 20% with respect to the thickness of the gas permeable film.

  The gas permeable film or gas permeable laminated film of the present invention is preferably a packaging film for maintaining freshness of fruits and vegetables and / or flowers.

  The gas permeable film of the present invention has a larger gas permeability of oxygen, carbon dioxide, etc. than conventional polypropylene films, and the freshness retention period can be extended when fruits and vegetables, flowers, etc. are sealed and packaged. . Furthermore, since the gas permeable multilayer film of the present invention is excellent in transparency and gas permeability, it is most suitable for freshness-keeping packaging of fruits and vegetables and flowers, and it is not necessary to provide a hole physically. Intrusion of substances can be prevented.

Hereinafter, the gas permeable film of this invention is demonstrated in detail for every structural requirement.
1. Propylene / ethylene block copolymer (A)
The propylene / ethylene block copolymer (A) according to the present invention has a melt flow rate of 1 to 10 g / 10 minutes, preferably 2 to 5 g / 10 minutes, and a melting point measured by a differential scanning calorimeter (DSC). 145-170 ° C, preferably 155-165 ° C, insoluble in room temperature n-decane (D _insol ) 90-70 wt% and room temperature n-decane soluble part (D _sol ) 10 30% by weight. Here, the melt flow rate in the propylene / ethylene block copolymer (A), the melting point, and the weight fraction of the portion soluble in n-decane (D _sol ) at room temperature are appropriately changed within the above range as necessary. can do.

In the propylene / ethylene block copolymer (A), D _sol is a requirement (
1) to (3) are satisfied, and D _insol satisfies the requirements (4) to (6).
(1) The molecular weight distribution (Mw / Mn) obtained from GPC (gel permeation chromatography) of D _insol is 1.0 to 3.5.

(2) The content of skeleton derived from ethylene in D _insol is less than 0.5 mol%.
(3) The sum of 2,1-insertion bond amount and 1,3-insertion bond amount of propylene in D _insol is 0.2 mol% or less.

(4) The molecular weight distribution (Mw / Mn) obtained from GPC of D _sol is 1.0 to 3.5.
(5) The intrinsic viscosity [η] in 135 ° C. decalin of D _sol is 1.5 to 4.5 dl / g
.

(6) The content of the skeleton derived from ethylene in D _sol is 15 mol% or more and less than 45 mol%.
Hereinafter, the requirements (1) to (6) included in the propylene-based copolymer (A) will be described in detail.

[Requirement (1)]
The molecular weight distribution (Mw / Mn) obtained from GPC (gel permeation chromatography) of the portion (D _insol ) insoluble in room temperature n-decane of the propylene / ethylene block copolymer (A) according to the present invention is 1.0. -3.5, preferably 1.0-3.0. In order to set the molecular weight distribution (Mw / Mn) determined from GPC to the above range for the portion insoluble in room temperature n-decane (D _insol ) contained in the copolymer as described above, the catalyst will be described later. Preferably, a metallocene catalyst is used. And, when Mw / Mn is larger than 3.5, low molecular weight components increase, so that there is a possibility of bleeding out of low molecular weight components from the gas permeable film of the present invention, and the transparency after heat treatment is lowered. This is also not preferable from the viewpoint of hygiene.

[Requirement (2)]
In the propylene / ethylene block copolymer (A) according to the present invention, the content of the skeleton derived from ethylene in the portion insoluble in room temperature n-decane (D _insol ) is less than 0.5 mol%. When the content of the skeleton derived from ethylene in D _insol is 0.5 mol% or more, the rigidity of the stretched film may be lowered.

[Requirement (3)]
The sum of the 2,1-insertion bond amount and the 1,3-insertion bond amount of propylene in the portion (D _insol ) insoluble in room temperature n-decane of the propylene / ethylene block copolymer (A) according to the present invention is 0
. It is 2 mol% or less, preferably 0.1 mol% or less. 2,1 of propylene in D _insol
-When the sum of the amount of insertion bonds and the amount of 1,3-insertion bonds is more than 0.2 mol%, the copolymerizability of propylene and ethylene decreases, and as a result, a portion soluble in room temperature n-decane. Since the composition distribution of the propylene / ethylene copolymer rubber in (D _sol ) is _broadened , the impact resistance may be lowered, and further problems such as reduced transparency may occur.

[Requirement (4)]
The molecular weight distribution (Mw / Mn) determined from GPC of the portion soluble in room temperature n-decane (Dsol) of the propylene / ethylene block copolymer (A) according to the present invention is 1.0 to 3.5, preferably 1.0 to 3.0. In order to narrow the molecular weight distribution (Mw / Mn) obtained from GPC as described above for the portion soluble in room temperature n-decane of the copolymer (D _sol ) as described above, it will be described later as a catalyst. A suitable metallocene catalyst is preferably used. And if Mw / Mn is larger than 3.5, since low molecular weight propylene / ethylene copolymer rubber increases in D _sol , problems such as lowering of impact resistance, deterioration of transparency, blocking during storage and the like occur. There is a case.
[Requirement (5)]
The intrinsic viscosity [η] in 135 ° C. decalin of the portion soluble in room temperature n-decane (D _sol ) of the propylene / ethylene block copolymer (A) according to the present invention is 1.5 to 4.5 dl / g.
, Preferably 1.5 to 3.5 dl / g. By making the intrinsic viscosity [η] of the portion soluble in room temperature n-decane (D _sol ) of the propylene / ethylene block copolymer (A) within such a range, there is no occurrence of fish eyes and the like and impact resistance A gas-permeable film having excellent properties can be obtained.

[Requirement (6)]
The content of the skeleton derived from ethylene in the portion soluble in room temperature n-decane (D _sol ) of the propylene / ethylene block copolymer (A) according to the present invention is 15 mol% or more and less than 45 mol%,
Preferably it is 15-35 mol%. The content of the skeleton derived from ethylene in D _sol is 15
If it is less than mol%, the impact resistance of the propylene / ethylene block copolymer (A) may be lowered. The content of the skeleton derived from ethylene in D _sol is 45 mol%.
If it exceeds 1, transparency may be lowered. In addition, the gas-permeable film of this invention makes content of the frame _| skeleton derived from ethylene in this room temperature n-decane soluble part ( _Dsol ) into the range of 15 mol% or more and less than 45 mol%. Further, the transparency is less likely to be lowered, and the impact resistance is less likely to be lowered.

  The propylene / ethylene block copolymer (A) according to the present invention is preferably composed of a propylene homopolymer or propylene and a small amount of ethylene in the first polymerization step ([Step 1]) in the presence of a metallocene catalyst. After producing the propylene copolymer, it is preferable to produce propylene / ethylene copolymer rubber by copolymerizing propylene and ethylene in the second polymerization step ([Step 2]).

The metallocene catalyst used in the present invention includes a metallocene compound and at least one compound selected from compounds capable of reacting with an organometallic compound, an organoaluminum oxy compound and a metallocene compound to form an ion pair, A metallocene catalyst comprising a particulate carrier as required, preferably a metallocene catalyst capable of performing stereoregular polymerization such as isotactic or syndiotactic structure. Among the metallocene compounds, the following crosslinkable metallocene compounds exemplified in the international application (WO01 / 27124 pamphlet) by the applicant of the present application are used.

In the general formula [I], R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ ,
R ¹¹ , R ¹² , R ¹³ , and R ¹⁴ are selected from a hydrogen atom, a hydrocarbon group, and a silicon-containing group, and may be the same or different. Such hydrocarbon groups include methyl, ethyl, n-propyl, allyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n -Linear hydrocarbon group such as nyl group and n-decanyl group; isopropyl group, tert-butyl group, amyl group, 3-methylpentyl group, 1,1-diethylpropyl group, 1,1-dimethylbutyl group Branched hydrocarbons such as 1-methyl-1-propylbutyl, 1,1-propylbutyl, 1,1-dimethyl-2-methylpropyl, 1-methyl-1-isopropyl-2-methylpropyl Groups: cyclic saturated hydrocarbon groups such as cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, norbornyl, adamantyl; phenyl, tolyl, naphthyl, biphenyl Cyclic unsaturated hydrocarbon groups such as enyl, phenanthryl and anthracenyl groups; saturated hydrocarbon groups substituted with cyclic unsaturated hydrocarbon groups such as benzyl, cumyl, 1,1-diphenylethyl and triphenylmethyl A hetero atom-containing hydrocarbon group such as methoxy group, ethoxy group, phenoxy group, furyl group, N-methylamino group, N, N-dimethylamino group, N-phenylamino group, pyryl group, thienyl group, etc. Can do. Examples of the silicon-containing group include a trimethylsilyl group, a triethylsilyl group, a dimethylphenylsilyl group, a diphenylmethylsilyl group, and a triphenylsilyl group.

In the general formula [I], the substituents R ^{5 to} R ¹² may be bonded to adjacent substituents to form a ring. Examples of such substituted fluorenyl groups include benzofluorenyl group, dibenzofluorenyl group, octahydrodibenzofluorenyl group, octamethyloctahydrodibenzofluorenyl group, octamethyltetrahydrodicyclopentafluorenyl group, etc. Can be mentioned.

In the general formula [I], R ¹ , R ² , R ³ , and R ⁴ substituted on the cyclopentadienyl ring are preferably a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms. Examples of the hydrocarbon group having 1 to 20 carbon atoms include the above-described hydrocarbon groups. More preferably, R ³ is a hydrocarbon group having 1 to 20 carbon atoms.

In the above general formula [I], R ^{5 to} R ¹² substituted on the fluorene ring have 1 to 20 carbon atoms.
The hydrocarbon group is preferably. Examples of the hydrocarbon group having 1 to 20 carbon atoms include the hydrocarbon groups listed above. In the substituents R ^{5 to} R ¹² , adjacent substituents may be bonded to each other to form a ring.

In the general formula [I], Y that bridges the cyclopentadienyl ring and the fluorenyl ring is preferably a group 14 element of the periodic table, more preferably carbon, silicon, or germanium, and still more preferably a carbon atom. It is. R ¹³ and R ¹⁴ substituted on Y are preferably a hydrocarbon group having 1 to 20 carbon atoms. These may be the same as or different from each other, and may be bonded to each other to form a ring. Examples of the hydrocarbon group having 1 to 20 carbon atoms include the hydrocarbon groups listed above. More preferably, R ¹⁴ is aryl having 6 to 20 carbon atoms (a
ryl) group. Examples of the aryl group include the above-mentioned cyclic unsaturated hydrocarbon group, a saturated hydrocarbon group substituted with a cyclic unsaturated hydrocarbon group, and a heteroatom-containing cyclic unsaturated hydrocarbon group. R ¹³ and R ¹⁴ may be the same as or different from each other, and may be bonded to each other to form a ring. As such a substituent, a fluorenylidene group, a 10-hydroanthracenylidene group, a dibenzocycloheptadienylidene group, and the like are preferable.

In the metallocene compound represented by the above general formula [I], the substituent selected from R ¹ , R ⁴ , R ⁵ or R ¹² and R ¹³ or R ^{14 at the} bridging part are bonded to each other to form a ring. May be.
In the above general formula [I], M is preferably a Group 4 transition metal of the periodic table, more preferably Ti, Zr, or Hf. Q is selected from the same or different combinations from a halogen atom, a hydrocarbon group, an anionic ligand, or a neutral ligand capable of coordinating with a lone electron pair. j is an integer of 1 to 4, and when j is 2 or more, Qs may be the same or different from each other. Specific examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and specific examples of the hydrocarbon group include the same as those described above. Specific examples of the anionic ligand include alkoxy groups such as methoxy, tert-butoxy and phenoxy, carboxylate groups such as acetate and benzoate, and sulfonate groups such as mesylate and tosylate. Specific examples of neutral ligands that can be coordinated by a lone pair include organophosphorus compounds such as trimethylphosphine, triethylphosphine, triphenylphosphine, diphenylmethylphosphine, tetrahydrofuran, diethyl ether, dioxane, 1,2-dimethoxy. And ethers such as ethane. It is preferable that at least one Q is a halogen atom or an alkyl group.

Such bridged metallocene compounds include diphenylmethylene (3-tert-butyl-5-methyl-cyclopentadienyl) (fluorenyl) zirconium dichloride, diphenylmethylene (3-tert-butyl-5-methyl-cyclopentadienyl). ) (2,
7-ditert-butylfluorenyl) zirconium dichloride, diphenylmethylene (3-tert-butyl-5-methyl-cyclopentadienyl) (3,6-ditert-butylfluorenyl) zirconium dichloride, (methyl) (Phenyl) methylene (3-tert-butyl-5-methyl-cyclopentadienyl) (octamethyloctahydrobenzofluorenyl) zirconium dichloride, [3- (1 ′, 1 ′, 4 ′, 4 ′, 7 ', 7', 10 ', 10'-octamethyloctahydrodibenzo [b, h] fluorenyl) (1,1,3-trimethyl-5-tert-butyl-1,2,3,3a-tetrahydropentalene) Zirconium dichloride (see the following formula [II]) and the like are preferred.

  In the metallocene catalyst used in the present invention, an ion pair reacts with an organometallic compound, an organoaluminum oxy compound, and a transition metal compound used together with the Group 4 transition metal compound represented by the general formula [I]. At least one compound selected from the compounds that form, and a particulate carrier that is used as necessary. These are disclosed in the above-mentioned publication (WO01 / 27124 pamphlet) or JP-A-11-315109. The compounds disclosed in the publication can be used without limitation.

  The propylene / ethylene block copolymer (A) in the present invention uses a polymerization apparatus in which two or more reaction apparatuses are connected in series, and continuously performs the following two steps ([Step 1] and [Step 2]). It is obtained by carrying out.

In [Step 1], propylene is homopolymerized or propylene and ethylene are copolymerized at a polymerization temperature of 0 to 100 ° C. and a polymerization pressure of normal pressure to 5 MPa gauge pressure. In [Step 1], the propylene homopolymer is fed alone, or the amount of ethylene feed relative to propylene is made small so that it is derived from ethylene in D _insol in the propylene-based polymer produced in [Step 1]. The content of the skeleton is less than 0.5 mol%, preferably 0.

In [Step 2], propylene and ethylene are copolymerized at a polymerization temperature of 0 to 100 ° C. and a polymerization pressure of normal pressure to 5 MPa gauge pressure. In [Step 2], the propylene / ethylene copolymer rubber produced in [Step 2] is made the main component of D _sol by increasing the amount of ethylene fed to propylene.

By doing in this way, requirements (1)-(3) concerning D _insol are adjusted by adjusting polymerization conditions in [Step 1], and requirements (4)-(6) concerning D _sol are [Step 2]. It can be satisfied by adjusting the polymerization conditions.

Further, the physical properties to be satisfied by the propylene / ethylene block copolymer (A) according to the present invention are often determined by the chemical structure of the metallocene catalyst used. Specifically, requirement (1) molecular weight distribution (Mw / Mn) obtained from GPC of D _insol , requirement (3) 2,1-insertion bond amount and 1,3-insertion bond amount of propylene in D _insol , Requirement (4) molecular weight distribution (Mw / Mn) determined from GPC of D _sol , and melting point of propylene / ethylene block copolymer (A) are mainly in [Step 1] and [Step 2]. By appropriate selection of the metallocene catalyst used, it can be adjusted to meet the requirements of the present invention. The metallocene catalyst preferably used in the present invention is as described above.

Furthermore, in order to make the content of the skeleton derived from ethylene in the requirement (2) D _insol less than 0.5 mol%, it is preferable to homopolymerize propylene in [Step 1]. In the case of copolymerization, the amount of ethylene fed in [Step 1] is preferably small. Requirement (5) The intrinsic viscosity [η] of D _sol in 135 ° C. decalin can be adjusted by the feed amount of a molecular weight regulator such as hydrogen in [Step 2]. Requirement (6) The content of the skeleton derived from ethylene in D _sol can be adjusted by the amount of ethylene feed in [Step 2]. Furthermore, by adjusting the amount ratio of the polymer produced in [Step 1] and [Step 2], the composition ratio of D _insol and D _sol and the melt flow of the propylene / ethylene block copolymer (A) The rate (ASTM D 1238, 230 ° C., load 2.16 kg) can be adjusted appropriately.

In addition, the propylene / ethylene block copolymer (A) according to the present invention includes a propylene homopolymer produced in [Step 1] of the above method and a propylene / ethylene copolymer produced in [Step 2] of the above method. The polymer rubber may be produced separately in the presence of a metallocene compound-containing catalyst and then blended using these physical means.
2. Ethylene / α-olefin random copolymer (B)
The gas permeable film of the present invention contains an ethylene / α-olefin random copolymer (B) in addition to the propylene / ethylene block copolymer (A), thereby providing impact resistance, transparency and gas permeability. Can be improved in a well-balanced manner.

  The content of the ethylene / α-olefin random copolymer (B) is more than 0 to 40% by weight (provided that the content of the propylene / ethylene block copolymer (A) + ethylene / α-olefin random copolymer ( By setting the content of B) to 100% by weight, a gas permeable film having an excellent balance between transparency and gas permeability can be obtained.

  In addition, by adjusting the content of the ethylene / α-olefin random copolymer (B), gas permeability, transparency, and film rigidity can be controlled. For example, in applications where transparency is more important than gas permeability and film rigidity, the content of ethylene / α-olefin random copolymer (B) (however, the content of propylene / ethylene block copolymer (A)) + Ethylene / α-olefin random copolymer (B) content = 100 wt%) is preferably 0 to 20 wt%, and more preferably 0 to 10 wt%.

  On the other hand, in applications where film rigidity and gas permeability are more important than transparency, the content of ethylene / α-olefin random copolymer (B) (however, the content of propylene / ethylene block copolymer (A)) + Content of ethylene / α-olefin random copolymer (B) = 100 wt%) is preferably 20 to 40 wt%, and more preferably 30 to 40 wt%.

  The α-olefin of the ethylene / α-olefin random copolymer (B) is preferably an α-olefin having 3 to 10 carbon atoms, and for the reason that it is easy to adjust the balance between gas permeability and transparency, 1 -Especially preferred is octene.

The ethylene / α-olefin random copolymer (B) used in the present invention preferably has an intrinsic viscosity [η] measured at 135 ° C. in decalin of 1.5 to 4.5 dl / g,
More preferably, it is 1.5 to 3.5 dl / g. Such an ethylene / α-olefin random copolymer (B) can be produced using a known vanadium catalyst or metallocene catalyst.
3. Other components The propylene / ethylene block copolymer (A) according to the present invention is a heat stabilizer, an antioxidant, a slip agent, an antiblocking agent, a plasticizer, a coloring agent, In addition to nucleating agents, weathering stabilizers, ultraviolet absorbers, etc., antifogging agents, antifogging agents, antibacterial agents, ethylene removing agents and the like can be contained. Anti-fogging agents are particularly useful because they have the effect of preventing the moisture content of the fruits and flowers from condensing on the inner surface of the gas-permeable packaging film and moistening the contents or deteriorating the transparency of the film. is there. Examples of the antifogging agent include known glycerin fatty acid esters, diglycerin fatty acid esters, sorbitan fatty acid esters, ethylene oxide adducts of alkylamines, ethylene oxide adducts of aliphatic amides, and the like. The content of the antifogging agent is usually 0.5 to 2.0% by weight.
4). Gas-permeable film and gas-permeable laminated film (1) Gas-permeable film The gas-permeable film of the present invention has a single-layer structure comprising a layer containing one layer of propylene / ethylene block copolymer (A). Alternatively, a multilayer structure composed of two or more layers containing a propylene / ethylene block copolymer (A) may be used.
(2) Gas-permeable laminated film The gas-permeable laminated film of the present invention has other layers other than the gas-permeable film, such as a heat seal layer, a reinforcing layer, and a surface protective layer, on at least one side of the gas-permeable film. It is a laminated structure formed by laminating.

  As the heat seal layer, a homo- or copolymer of α-olefin such as ethylene, propylene, butene-1, hexene-1, hexene-1, 4-methylpentene-1, octene-1, etc., which are generally known as heat seal layers, high pressure method Low density polyethylene, linear low density polyethylene (so-called LLDPE), high density polyethylene, polypropylene, polypropylene random copolymer, polybutene, poly-4-methyl pentene-1, low crystalline or amorphous ethylene / propylene random copolymer Polymer, ethylene / butene-1 random copolymer, composition containing polyolefin such as propylene / butene-1 random copolymer alone or in combination of two or more, ethylene / vinyl acetate copolymer (EVA), ethylene / (meta ) Acrylic acid copolymer or its metal salt, EVA and polyolefin A layer obtained from the composition or the like with. Among these, a heat seal layer obtained from an ethylene-based polymer such as high-pressure method low-density polyethylene, linear low-density polyethylene (so-called LLDPE), or high-density polyethylene is preferable because it is excellent in low-temperature heat sealability and heat seal strength.

  Among these, it is preferable to use a gas-permeable laminated film in which a layer containing a propylene-based polymer (C) is laminated on at least one side of the gas-permeable film of the present invention, and a coextruded sheet is stretched in cast molding. And can be formed into a film.

Examples of the propylene polymer (C) used in the gas permeable laminated film of the present invention include a propylene homopolymer (C1) or a propylene random copolymer (C2).
The propylene random copolymer (C2) is specifically a propylene-α-olefin copolymer, and examples of the α-olefin include ethylene, 1-butene, 1-pentene, and 1-hexene. 1-heptene, 1-octene, 1-decene, 1-dodecene, 1-hexadodecene, 4-methyl-1-pentene, 2-methyl-1-butene, 3-methyl-1-butene, 3-methyl-1 -Butene, 3,3-dimethyl-1-butene, diethyl-1-butene, trimethyl-1-butene, 3-methyl-1-pentene, ethyl-1-pentene, propyl-1-pentene, dimethyl-1-pentene , Methylethyl-1-pentene, diethyl-1-hexene, trimethyl-1-pentene, 3-methyl-1-hexene, dimethyl-1-hexe 3,5,5-trimethyl-1-hexene, methylethyl-1-heptene, trimethyl-1-heptene, dimethyloctene, ethyl-1-octene, methyl-1-nonene, vinylcyclopentene, vinylcyclohexane, vinylnorbornane, etc. Is mentioned. One or more of these α-olefins can be contained in the propylene-α-olefin copolymer in a total amount of 10 mol% or less.

Further, MFR (ASTM D1238) measured at 230 ° C. of the propylene-based polymer (C).
(230 ° C., load 2.16 kg) is usually in the range of 1 to 20 g / 10 minutes, preferably 2 to 10 g / 10 minutes, more preferably 4 to 10 g / 10 minutes. An MFR in this range is preferable because the moldability and appearance of the film are good.

  The melting point Tm of the propylene polymer (C) is in the range of 120 to 150 ° C, preferably 130 to 145 ° C. When the melting point Tm is in this range, there is no stickiness of the film, transparency and sealing properties are good, and gas permeability is high, which is preferable.

Moreover, it is preferable that the thickness of the layer containing the propylene polymer (C) in the gas permeable laminated film is in the range of 1 to 20% with respect to the thickness of the gas permeable film. It is more preferable to be within the above range, and the rigidity and heat resistance of the gas permeable laminated film can be improved.
(3) Shape of gas permeable film and gas permeable laminated film The thickness of the gas permeable film or the gas permeable laminated film is not particularly limited because it depends on the kind of fruits and flowers to be packaged and the packaging purpose. However, it is 10-100 micrometers normally, Preferably it is 10-60 micrometers, More preferably, it is 10-30 micrometers.
(4) Characteristics of gas permeable film and gas permeable laminated film (i) Haze value (JIS K7105)
The haze value measured according to JIS K7105 of the gas permeable film and gas permeable laminated film of the present invention is preferably less than 10%, and preferably less than 7%. When the haze value is in such a range, the visibility of the packaged contents (fruits and vegetables, etc.) is not impaired, and the appearance is good. For the same reason, JIS of gas permeable laminated film
The haze value measured according to K7105 is preferably less than 10%.
(Ii) Tensile modulus in MD direction The tensile modulus in the MD direction of the gas-permeable film and gas-permeable laminated film of the present invention is preferably 1800 MPa or more, and more preferably 2000 MPa or more. When the tensile elastic modulus is within this range, the gas permeable film and the gas permeable laminate have sufficient rigidity, and the waist does not run out.
(Iii) Oxygen permeability The oxygen permeability of the gas permeable film and the gas permeable laminated film of the present invention is preferably 1.6 × 10 ⁻¹¹ mol / m ² · s · Pa or more, and 1.8 It is more preferable to set it as ^x10 < ^-11 > mol / m < ² > * s * Pa or more, and it is more preferable to set it as 2.0 * 10 < ^-11 > mol / m < ² > * s * Pa or more. When the oxygen permeability is within this range, the freshness maintaining effect is enhanced.

Such a gas permeable film and gas permeable laminated film of the present invention are excellent in transparency, have an appropriate rigidity and a high oxygen permeability, and therefore, the freshness is maintained by packaging fruits and vegetables and the like. It is suitably used as a packaging film for maintaining freshness, and in particular, it is suitably used as a packaging film for maintaining freshness for wrapping fruits and vegetables and keeping freshness.
5. Gas-permeable film and gas-permeable laminated film forming method The gas-permeable film of the present invention is formed by a known method such as a T-die method, an inflation method, or a calendar method. The gas permeable laminated film is formed by multilayer molding by coextrusion or by laminating another resin layer by an extrusion lamination method or a dry lamination method.

  The gas permeable film and gas permeable laminated film of the present invention are desirably stretched in at least a uniaxial direction, more preferably in a biaxial direction, in order to improve strength, optical properties, and appearance. Examples of the stretching method include a roll method, a tenter method, a tubular method, and the like. Further, in the case of biaxial stretching, sequential biaxial stretching or simultaneous biaxial stretching can be performed. The stretching ratio is preferably 3 to 8 times in the case of uniaxial stretching, and preferably in the range of 10 to 60 times in the case of biaxial stretching.

EXAMPLES Next, although this invention is demonstrated in detail based on an Example, this invention is not limited to the Example which concerns. In addition, the measuring method of the physical property in an Example and a comparative example is as follows.
(M1) Melt flow rate (MFR)
MFR was measured according to ASTM D1238 (230 ° C., load 2.16 kg).

(M2) Melting point (Tm)
The measurement was performed using a differential scanning calorimeter (DSC, manufactured by Perkin Elmer). The endothermic peak in the third step measured here was defined as the melting point (Tm).

(Measurement condition)
First step: Increase the temperature to 240 ° C at 10 ° C / min and hold for 10 min.
Second step: Decrease the temperature to 60 ° C at 10 ° C / min.

Third step: Increase the temperature to 240 ° C at 10 ° C / min.
(M3) Room temperature n-decane soluble part (D _sol )
200 ml of n-decane was added to 5 g of the final product sample and dissolved by heating at 145 ° C. for 30 minutes. It was cooled to 20 ° C. over about 3 hours and left for 30 minutes. Thereafter, the precipitate (hereinafter, n-decane insoluble part: D _insol ) was filtered off. The filtrate was put in about 3 times the amount of acetone to precipitate the components dissolved in n-decane (precipitate (A)). The precipitate (A) and acetone were separated by filtration, and the precipitate was dried. Even when the filtrate side was concentrated to dryness, no residue was observed.

The amount of n-decane soluble part was determined by the following formula.
n-decane soluble part amount (wt%) = [precipitate (A) weight / sample weight] × 100.
(M4) Mw / Mn measurement [weight average molecular weight (Mw), number average molecular weight (Mn)]
Measurement was performed as follows using GPC-150C Plus manufactured by Waters. The separation columns are TSKgel GMH6-HT and TSKgel GMH6-HTL, the column size is 7.5 mm in inner diameter and 600 mm in length, the column temperature is 140 ° C., the mobile phase is o-dichlorobenzene (Wako Pure Chemical Industries, Ltd.) Co.) and 0.025% by weight of BHT (Wako Pure Chemical Industries, Ltd.) as an antioxidant, moved at 1.0 ml / min, the sample concentration was 0.1% by weight, and the sample injection volume was 500 μl. A differential refractometer was used as a detector. Standard polystyrene used was manufactured by Tosoh Corporation for molecular weights of Mw <1000 and Mw> 4 × 10 ⁶ , and used by Pressure Chemical Co. for 1000 ≦ Mw ≦ 4 × 10 ⁶ .

(M5) Content of skeleton derived from ethylene
To measure the skeleton concentration derived from ethylene in D _insol and D _sol , 20-30 mg of sample was dissolved in 0.6 ml of 1,2,4-trichlorobenzene / heavy benzene (2: 1) solution, and then carbon nuclear magnetism. Resonance analysis ( ¹³ C-NMR) was performed. Propylene, ethylene, and α-olefin were quantitatively determined from the dyad chain distribution. For example, in the case of propylene-ethylene copolymer,

Was obtained by the following calculation formulas (Eq-1) and (Eq-2).

(M6) Intrinsic viscosity [η]
Measurement was performed at 135 ° C. using a decalin solvent. About 20 mg of the sample was dissolved in 15 ml of decalin, and the specific viscosity ηsp was measured in an oil bath at 135 ° C. After diluting the decalin solution with 5 ml of decalin solvent, the specific viscosity ηsp was measured in the same manner. Repeat this dilution operation two more times,
The value of ηsp / C when the concentration (C) was extrapolated to 0 was determined as the intrinsic viscosity.

[Η] = lim (ηsp / C) (C → 0).
(M7) Measurement of 2,1-insertion bond and 1,3-insertion bond
^{Using 13} C-NMR, the amount of 2,1-insertion bond and the amount of 1,3-insertion bond of propylene were measured according to the method described in JP-A-7-152212.

(M8) Gas Permeability of Film Using a gas permeability measuring device MT-C3 type (manufactured by Toyo Seiki Seisakusho Co., Ltd.), in accordance with A method of JIS K7126, the conditions are 23 ° C. and 0% RH. And measure the oxygen permeability [GTR (O ₂ )] and carbon dioxide permeability [GTR (CO ₂ )] of the film, and calculate the ratio (GTR (CO ₂ ) / GTR (O ₂ )). did.

(M9) Film haze (HAZE)
The haze of one film was measured according to JIS K7105.
[Production Example 1] Production of propylene / ethylene block copolymer (A1)
(1) Production of solid catalyst support 300 g of SiO ₂ was sampled in a 1 L branch flask, and 800 mL of toluene was added.
After slurrying, the solution was transferred to a 5 L 4-neck flask, and 260 mL of toluene was added. 2830 mL of a toluene solution (10 wt% solution) of methylaluminoxane (hereinafter referred to as MAO) was added and stirred at room temperature for 30 minutes. The temperature was raised to 110 ° C. over 1 hour and reacted for 4 hours. After completion of the reaction, the temperature was lowered to room temperature. After cooling, the supernatant toluene solution was removed, toluene was added again, and substitution was performed until the substitution rate reached 95%.

(2) Production of solid catalyst (support of metal catalyst component on support)
In a glove box, add a 5-L four-necked flask to [3- (1 ', 1', 4 ', 4', 7 ', 7', 10 ', 10'-octamethyloctahydrodibenzo [b, h ] Fluorenyl) (1,1,3-trimethyl-5-tert-butyl-1,2,3,3a-tetrahydropentalene)] zirconium dichloride was weighed in 2.0 g. The flask was taken out and MAO / Si prepared with 0.46 liters of toluene and (1)
1.4 liters of O ₂ / toluene slurry was added under nitrogen and stirred for 30 minutes to carry. The resulting [3- (1 ′, 1 ′, 4 ′, 4 ′, 7 ′, 7 ′, 10 ′, 10′-octamethyloctahydrodibenzo [b, h] fluorenyl) (1,1,3- Trimethyl-5-tert-butyl-1,2,3,3a-tetrahydropentalene)]
Zirconium dichloride / MAO / SiO ₂ / toluene slurry is 99 in n-heptane.
% Substitution was performed and the final slurry volume was 4.5 liters. This operation was performed at room temperature.

(3) Production of prepolymerization catalyst 404 g of the solid catalyst component prepared in (2) above, 218 mL of triethylaluminum, and 100 L of heptane were inserted into an autoclave equipped with a stirrer with an internal volume of 200 L, and the internal temperature was maintained at 15 to 20 ° C. and 1212 g of ethylene was inserted And allowed to react with stirring for 180 minutes. After completion of the polymerization, the solid component was settled, the supernatant was removed, and washed twice with heptane. The obtained prepolymerized catalyst was resuspended in purified heptane and adjusted with heptane so that the solid catalyst component concentration was 4 g / L. This prepolymerized catalyst contained 3 g of polyethylene per 1 g of the solid catalyst component.

(4) Main polymerization In a tubular polymerization vessel having an internal volume of 58 L, propylene is 30 kg / hour, hydrogen is 2 NL / hour, the catalyst slurry produced in (3) is 3.5 g / hour as a solid catalyst component, and 2.3 ml of triethylaluminum. / Time was continuously supplied, and the polymerization was carried out in a full liquid state without a gas phase. The temperature of the tubular reactor was 30 ° C., and the pressure was 3.1 MPa / G.

  The obtained slurry was sent to a vessel polymerization vessel with a stirrer having an internal volume of 100 L, and further polymerization was performed. Propylene was supplied at 15 kg / hour, and hydrogen was supplied to the polymerization reactor so that the hydrogen concentration in the gas phase was 0.2 mol%. Polymerization was performed at a polymerization temperature of 70 ° C. and a pressure of 3.0 MPa / G.

The obtained slurry was transferred to a sandwiching tube having an internal volume of 2.4 L, gasified, gas-solid separated, and then propylene homopolymer powder was sent to a 480 L gas phase polymerization vessel to produce ethylene / propylene block copolymer. Went. Propylene, ethylene, and hydrogen are continuously supplied so that the gas composition in the gas phase polymerizer is ethylene / (ethylene + propylene) = 0.52 (molar ratio) and hydrogen / ethylene≈0 (molar ratio). did. Polymerization was performed at a polymerization temperature of 70 ° C. and a pressure of 1.1 MPa / G.

After the polymerization, vacuum drying was performed at 80 ° C. to obtain a propylene / ethylene block copolymer (A1). Table 1 shows the physical properties of the resulting propylene / ethylene block copolymer (A1).

[Production Example 2] Production of propylene / ethylene block copolymer (A2) A propylene / ethylene block copolymer (A2) was produced in the same manner as in Production Example 1 except that the polymerization method was changed as follows. .

(1) Main polymerization In a tubular polymerization vessel having an internal volume of 58 L, propylene is 30 kg / hour, hydrogen is 1 NL / hour, the catalyst slurry produced in Production Example 1 (3) is 6.2 g / hour, and triethylaluminum 2 .3 ml / hour was continuously supplied, and polymerization was performed in a full liquid state without a gas phase. The temperature of the tubular reactor was 30 ° C., and the pressure was 3.1 MPa / G.

  The obtained slurry was sent to a vessel polymerization vessel equipped with a stirrer having an internal volume of 100 L and further polymerized. Propylene was supplied to the polymerization vessel at 15 kg / hour, and hydrogen was supplied so that the hydrogen concentration in the gas phase was 0.09 mol%. Polymerization was performed at a polymerization temperature of 70 ° C. and a pressure of 3.0 MPa / G.

The obtained slurry was transferred to a sandwiching tube having an internal volume of 2.4 L, gasified, gas-solid separated, and then propylene homopolymer powder was sent to a 480 L gas phase polymerization vessel to produce ethylene / propylene block copolymer. Went. Propylene, ethylene, and hydrogen were continuously supplied so that the gas composition in the gas phase polymerizer would be ethylene / (ethylene + propylene) = 0.10 (molar ratio) and hydrogen / ethylene≈0 (molar ratio). . Polymerization was performed at a polymerization temperature of 70 ° C. and a pressure of 1.1 MPa / G.

After the polymerization, vacuum drying was performed at 80 ° C. to obtain a propylene / ethylene block copolymer (A2). Table 1 shows the physical properties of the resulting propylene / ethylene block copolymer (A2).
[Production Example 3] Production of propylene / ethylene block copolymer (A3) A propylene / ethylene block copolymer (A3) was produced in the same manner as in Production Example 1 except that the polymerization method was changed as follows. .

(1) Main polymerization In a tubular polymerization vessel having an internal volume of 58 L, propylene is 30 kg / hour, hydrogen is 1 NL / hour, the catalyst slurry produced in Production Example 1a (3) is used as a solid catalyst component, 6.2 g / hour, triethylaluminum 2 .3 ml / hour was continuously supplied, and polymerization was performed in a full liquid state without a gas phase. The temperature of the tubular reactor was 30 ° C., and the pressure was 3.1 MPa / G.

  The obtained slurry was sent to a vessel polymerization vessel equipped with a stirrer having an internal volume of 100 L and further polymerized. Propylene was supplied at 15 kg / hour, and hydrogen was supplied to the polymerization reactor so that the hydrogen concentration in the gas phase was 0.09 mol%. Polymerization was performed at a polymerization temperature of 70 ° C. and a pressure of 3.0 MPa / G.

The obtained slurry was transferred to a sandwiching tube having an internal volume of 2.4 L, gasified, gas-solid separated, and then propylene homopolymer powder was sent to a 480 L gas phase polymerization vessel to produce ethylene / propylene block copolymer. Went. Propylene, ethylene, and hydrogen were continuously supplied so that the gas composition in the gas phase polymerizer would be ethylene / (ethylene + propylene) = 0.10 (molar ratio) and hydrogen / ethylene≈0 (molar ratio). . Polymerization was performed at a polymerization temperature of 70 ° C. and a pressure of 0.9 MPa / G.

After the polymerization, vacuum drying was performed at 80 ° C. to obtain a propylene / ethylene block copolymer (A3). Table 1 shows the physical properties of the resulting propylene / ethylene block copolymer (A3).
[Production Example 4] Production of propylene / ethylene block copolymer (A4) A propylene / ethylene block copolymer (A4) was produced in the same manner as in Production Example 1 except that the polymerization method was changed as follows. .

(1) Main polymerization In a tubular polymerization vessel having an internal volume of 58 L, propylene is 30 kg / hour, hydrogen is 1 NL / hour, the catalyst slurry produced in Production Example 1a (3) is used as a solid catalyst component, 6.2 g / hour, triethylaluminum 2 .3 ml / hour was continuously supplied, and polymerization was performed in a full liquid state without a gas phase. The temperature of the tubular reactor was 30 ° C., and the pressure was 3.1 MPa / G.

  The obtained slurry was sent to a vessel polymerization vessel equipped with a stirrer having an internal volume of 100 L and further polymerized. Propylene was supplied to the polymerization vessel at 15 kg / hour, and hydrogen was supplied so that the hydrogen concentration in the gas phase was 0.09 mol%. Polymerization was performed at a polymerization temperature of 70 ° C. and a pressure of 3.0 MPa / G.

The obtained slurry was transferred to a sandwiching tube having an internal volume of 2.4 L, gasified, gas-solid separated, and then propylene homopolymer powder was sent to a 480 L gas phase polymerization vessel to produce ethylene / propylene block copolymer. Went. Propylene, ethylene, and hydrogen were continuously supplied so that the gas composition in the gas phase polymerization reactor was ethylene / (ethylene + propylene) = 0.20 (molar ratio) and hydrogen / ethylene≈0 (molar ratio). . Polymerization was performed at a polymerization temperature of 70 ° C. and a pressure of 1.0 MPa / G.

  After the polymerization, vacuum drying was performed at 80 ° C. to obtain a propylene / ethylene block copolymer (A4). Table 1 shows the physical properties of the resulting propylene / ethylene block copolymer (A4).

Example (single layer film)
[ Reference Example 1]
Using the T-die molding machine (die lip width: 200 mm, extruder: 30 mmφ, L / D = 25) for the propylene / ethylene block copolymer (A1) produced in Production Example 1, the resin temperature: 230 ° C., An original sheet having a thickness of 500 μm was obtained at a die temperature of 230 ° C., a chill roll temperature of 30 ° C., and a take-up speed of 1 m / min. Next, this raw fabric sheet was successively biaxially stretched at a stretching temperature of 145 ° C., a stretching speed of 10 m / min, and a stretching ratio of 5 (MD) × 5 (TD) to obtain a biaxially stretched film having a thickness of 20 μm. .
The film was measured for haze, oxygen permeability [GTR (O ₂ )] and carbon dioxide permeability [GTR (CO ₂ )]. The measurement results are shown in Table 2.
[ Reference Example 2]
The measurement was performed in the same manner as in Reference Example 1 except that the propylene / ethylene block copolymer (A1) was changed to the propylene / ethylene block copolymer (A2) produced in Production Example 2. The measurement results are shown in Table 2.
[ Reference Example 3]
The measurement was performed in the same manner as in Reference Example 1 except that the propylene / ethylene block copolymer (A1) was changed to the propylene / ethylene block copolymer (A3) produced in Production Example 3. The measurement results are shown in Table 2.
[ Reference Example 4]
The measurement was performed in the same manner as in Reference Example 1 except that the propylene / ethylene block copolymer (A1) was changed to the propylene / ethylene block copolymer (A4) produced in Production Example 4. The measurement results are shown in Table 2.
[Example 5]
With respect to 95 parts by weight of the propylene / ethylene block copolymer (A2) produced in Production Example 2, ethylene-1-octene random copolymer (MFR = (JIS K7210 190 ° C.) 1 g / 10 min, 1-octene amount) = 15 mol%) After 5 parts by dry blending with a tumbler, using a twin screw extruder (screw diameter: 36 mm, L / D = 31), the resin composition was melt-kneaded at 230 ° C. to obtain a resin composition. Obtained.

Using this resin composition, a T-die molding machine (die lip width: 200 mm, extruder: 30 mmφ, L / D = 25), resin temperature: 230 ° C., die temperature: 230 ° C., chill roll temperature: 30 ° C., take-off An original sheet having a thickness of 500 μm was obtained at a speed of 1 m / min. Next, this raw fabric sheet was stretched at a stretching temperature of 145 ° C., a stretching speed of 10 m / min, and a stretching ratio of 5 (MD) × 5 (
TD) was sequentially biaxially stretched to obtain a biaxially stretched film having a thickness of 20 μm.
The film was measured for haze, oxygen permeability [GTR (O ₂ )] and carbon dioxide permeability [GTR (CO ₂ )]. The measurement results are shown in Table 2.
[Example 6]
Measurement was carried out in the same manner as in Example 5 except that 90 parts by weight of the propylene / ethylene block copolymer (A2) and 10 parts by weight of the ethylene-1-octene random copolymer were used. The measurement results are shown in Table 2.
[Example 7]
Measurement was carried out in the same manner as in Example 5 except that 80 parts by weight of the propylene / ethylene block copolymer (A2) and 20 parts by weight of the ethylene-1-octene random copolymer were used. The measurement results are shown in Table 2.
[Comparative Example 1]
Measurement was carried out in the same manner as in Example 6 except that Prime Polypro F300SP (MFR = 3.0 g / 10 min manufactured by Prime Polymer Co., Ltd.), which is a propylene homopolymer, was used instead of the propylene / ethylene block copolymer (A2). Carried out. The measurement results are shown in Table 2.
[Comparative Example 2]
Measurement was performed in the same manner as in Example 7 except that Prime Polypropylene F300SP (MFR = 3.0 g / 10 min manufactured by Prime Polymer Co., Ltd.), which is a propylene homopolymer, was used instead of the propylene / ethylene block copolymer (A2). Carried out. The measurement results are shown in Table 2.
[Comparative Example 3]
The same procedure as in Example 6 was performed except that Prime Polypro E601 (MFR = 0.9 g / 10 min, manufactured by Prime Polymer Co., Ltd.), which is a propylene / ethylene block copolymer, was used instead of the propylene / ethylene block copolymer (A2). The measurement was carried out. The measurement results are shown in Table 2.
Example (laminated film)

[ Reference Example 8]
The propylene / ethylene block copolymer (A1) is charged into a base layer extruder (30 mmφ, L / D = 25) of a two-type three-layer T-die molding machine (die lip width: 200 mm), and propylene-ethylene-1-butene random copolymer (MFR = 7g / 10 m in , ethylene content = 3.3 mol%, 1-butene content = 1.5 mol%) was charged into a surface layer extruder (25mmφ, L / D = 25 ), Resin temperature: 230 ° C., die temperature: 230 ° C., chill roll temperature: 30 ° C., take-up speed: 1 m / min. At that time, the discharge amount was adjusted so that the thickness per surface layer was 5.5% of the thickness of the base layer. Next, this raw fabric sheet was successively biaxially stretched at a stretching temperature of 145 ° C., a stretching speed of 10 m / min, and a stretching ratio of 5 (MD) × 5 (TD) to obtain a biaxially stretched film having a thickness of 20 μm. .
The film was measured for haze, oxygen permeability [GTR (O ₂ )] and carbon dioxide permeability [GTR (CO ₂ )]. Table 3 shows the measurement results.
[ Reference Example 9]
The measurement was performed in the same manner as in Reference Example 8 except that the propylene / ethylene block copolymer (A1) was changed to the propylene / ethylene block copolymer (A2). Table 3 shows the measurement results.
[ Reference Example 10]
The measurement was performed in the same manner as in Reference Example 8 except that the propylene / ethylene block copolymer (A1) was changed to the propylene / ethylene block copolymer (A3). Table 3 shows the measurement results.
[ Reference Example 11]
The measurement was performed in the same manner as in Reference Example 8 except that the propylene / ethylene block copolymer (A1) was changed to the propylene / ethylene block copolymer (A4). Table 3 shows the measurement results.
[Example 12]
5 parts by weight of ethylene-1-octene random copolymer (MFR = (JIS K7210 190 ° C.) 1 g / 10 min, 1-octene amount = 15 mol%) with respect to 95 parts by weight of propylene / ethylene block copolymer (A2) After dry blending with a tumbler, a twin screw extruder (screw diameter: 36 mm, L / D = 31) was used and melt kneaded at a resin temperature of 230 ° C. to obtain a resin composition for a base layer. This resin composition was put into a base layer extruder (30 mmφ, L / D = 25) of a two-type three-layer T-die molding machine (die lip width: 200 mm), and a propylene-ethylene-1-butene random copolymer (MFR). = 7g / 10 m in, ethylene content = 3.3 mol%, was charged with 1-butene content = 1.5 mol%) in the surface layer extruder (25mmφ, L / D = 25 ), resin temperature: 230 ° C., An original sheet having a thickness of 500 μm was obtained at a die temperature of 230 ° C., a chill roll temperature of 30 ° C., and a take-up speed of 1 m / min. At that time, the discharge amount was adjusted so that the thickness per surface layer was 5.5% of the thickness of the base layer. Next, this raw fabric sheet was successively biaxially stretched at a stretching temperature of 145 ° C., a stretching speed of 10 m / min, and a stretching ratio of 5 (MD) × 5 (TD) to obtain a biaxially stretched film having a thickness of 20 μm. .
The film was measured for haze, oxygen permeability [GTR (O ₂ )] and carbon dioxide permeability [GTR (CO ₂ )]. Table 3 shows the measurement results.
[Example 13]
Measurement was carried out in the same manner as in Example 12 except that 90 parts by weight of the propylene / ethylene block copolymer (A2) and 10 parts by weight of the ethylene-1-octene random copolymer were used. Table 3 shows the measurement results.
[Example 14]
Measurement was carried out in the same manner as in Example 12 except that 80 parts by weight of the propylene / ethylene block copolymer (A2) and 20 parts by weight of the ethylene-1-octene random copolymer were used. Table 3 shows the measurement results.
[Comparative Example 4]
Measurement was carried out in the same manner as in Example 13 except that Prime Polypro F300SP (MFR = 3.0 g / 10 min manufactured by Prime Polymer Co., Ltd.), which is a propylene homopolymer, was used instead of the propylene / ethylene block copolymer (A2). Carried out. Table 3 shows the measurement results.
[Comparative Example 5]
Measurement was carried out in the same manner as in Example 14 except that Prime Polypro F300SP (MFR = 3.0 g / 10 min manufactured by Prime Polymer Co., Ltd.), which is a propylene homopolymer, was used instead of the propylene / ethylene block copolymer (A2). Carried out. Table 3 shows the measurement results.
[Comparative Example 6]
The same procedure as in Example 13 was performed except that Prime Polypro E601 (MFR = 0.9 g / 10 min, manufactured by Prime Polymer Co., Ltd.), which is a propylene / ethylene block copolymer, was used instead of the propylene / ethylene block copolymer (A2). The measurement was carried out. Table 3 shows the measurement results.

  The gas permeable film or gas permeable multilayer film of the present invention has a large gas permeability of oxygen, carbon dioxide, etc., as compared with the conventional polypropylene film, and can extend the freshness retention period of the contents, Since it is not necessary to physically provide a hole, it is possible to prevent entry of contaminants from the outside, which is optimal as a packaging film for keeping freshness of fruits and vegetables.

Claims (5)

The melt flow rate (ASTM D 1238, 230 ° C., load 2.16 kg) is in the range of 1-10 g / 10 min;
The melting point measured with a differential scanning calorimeter (DSC) is in the range of 145 to 170 ° C .;
A portion insoluble in room temperature n-decane (D _insol ) satisfying the following (1) to (3) (D _insol ) and a portion soluble in room temperature n-decane (D _sol ) satisfying the following (4) to (6) Propylene / ethylene block copolymer (A) composed of 10 to 30% by weight ;
Ethylene · alpha-olefin random copolymer (B) and <br/> a including gas permeable film,
Content of the ethylene / α-olefin random copolymer (B) is more than 0 to 40% by weight (provided that the content of propylene / ethylene block copolymer (A) + ethylene / α-olefin random copolymer) The content of (B) = 100% by weight).
The α-olefin of the ethylene / α-olefin random copolymer (B) is 1-octene.
Gas permeable film
A packaging film for maintaining the freshness of fruits and vegetables and / or flowers, comprising :
(1) The molecular weight distribution (Mw / Mn) determined from GPC (gel permeation chromatography) of D _insol is 1.0 to 3.5.
(2) The content of the skeleton derived from ethylene in D _insol is less than 0.5 mol%. (3) The sum of the 2,1-insertion bond amount and 1,3-insertion bond amount of propylene in D _insol is 0.2 mol% or less (4) The molecular weight distribution (Mw / Mn) determined from GPC of D _sol is 1.0 to 3.5.
(5) The intrinsic viscosity [η] in 135 ° C. decalin of D _sol is 1.5 to 4.5 dl / g
(6) The content of the skeleton derived from ethylene in D _sol is 15 mol% or more and less than 45 mol%. The melt flow rate (ASTM D 1238, 230 ° C., load 2.16 kg) is in the range of 1-10 g / 10 min;
The melting point measured with a differential scanning calorimeter (DSC) is in the range of 145 to 170 ° C .;
Part insoluble in room temperature n-decane satisfying the following (1) to (3) (D _insol A portion soluble in room temperature n-decane satisfying 90 to 70% by weight and the following (4) to (6) (D _sol Propylene / ethylene block copolymer (A) composed of 10 to 30% by weight;
Ethylene / α-olefin random copolymer (B) and
A gas permeable film comprising
Content of the ethylene / α-olefin random copolymer (B) is more than 0 to 40% by weight (provided that the content of propylene / ethylene block copolymer (A) + ethylene / α-olefin random copolymer) The content of (B) = 100% by weight).
The α-olefin of the ethylene / α-olefin random copolymer (B) is 1-octene.
On at least one side of the gas permeable film,
Layer containing propylene polymer (C)
Gas permeable laminated film made by laminating
A packaging film for maintaining the freshness of fruits and vegetables and / or flowers.
(1) D _insol Molecular weight distribution (Mw / Mn) determined from GPC (gel permeation chromatography) of 1.0 to 3.5
(2) D _insol Content of skeleton derived from ethylene is less than 0.5 mol%
(3) D _insol The sum of the amount of 2,1-insertion bonds and the amount of 1,3-insertion bonds in propylene is 0.2 mol% or less.
(4) D _sol Molecular weight distribution (Mw / Mn) determined from GPC of 1.0 to 3.5
(5) D _sol The intrinsic viscosity [η] in decalin at 135 ° C. is 1.5 to 4.5 dl / g
(6) D _sol The content of the skeleton derived from ethylene is 15 mol% or more and less than 45 mol%. The thickness of the layer containing the propylene-based polymer (C) is, relative to the thickness of the gas permeable film, a wrapping freshness of claim 2, characterized in that in the range of 1-20% Film .
The freshness-keeping packaging film according to any one of claims 1 to 3, wherein the propylene / ethylene block copolymer (A) is polymerized in the presence of a metallocene catalyst. The freshness-keeping packaging film according to any one of claims 1 to 4 , wherein the gas permeable film is stretched in a biaxial direction.