JP2003311830A - Polypropylene film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polypropylene film formed by inflation film molding, excellent in cold impact resistance, low temperature sealability and rigidity and further excellent in heat resistance, chemical resistance, oil resistance, aroma retention, sanitary properties, the adjustment of seal strength (easy peel properties), mechanical properties and economical efficiency. <P>SOLUTION: The polypropylene film is formed by the air cooling type inflation film molding of a resin composition containing 50-97 wt.% of a polypropylene resin and 3-50 wt.% of an α-olefin copolymer. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a single-layer or multi-layer polypropylene film formed by inflation molding from a polypropylene resin composition. More specifically, rigidity, cold shock resistance, low temperature sealability,
The present invention relates to a polypropylene film having excellent heat resistance, chemical resistance, oil resistance, aroma retention, adjustment of seal strength (easy peeling), mechanical suitability, and economy.

Conventionally, unstretched polypropylene film is
It has excellent transparency, heat resistance, moisture resistance, mechanical suitability, gloss, etc., and is widely used in the packaging field as a heat-sealing layer when laminated with various substrate films.

On the other hand, as a film forming method, a T-die casting method or an inflation method (water cooling type, air cooling type) has been conventionally used. The film forming method by the T-die casting method is a method of forming a flat film by forming a flat film by attaching a T die to the tip of an extruder. The film formation method by the water-cooled inflation method uses a die having an annular slit at the tip of the extruder, extrudes the molten resin into a tube shape, sandwiches the tip with pinch rolls, and blows a fixed amount of air into it to give a predetermined size. To blow, cool the air by blowing air on the outer peripheral surface of the expanded tube, then immerse in a cooling water tank, or after showering with cooling water, remove water adhering to the folding film surface with a stabilizer and pinch rolls, It is a method of winding after drying. The film formation method by the air-cooled inflation method uses a die having an annular slit at the tip of the extruder to extrude the molten resin to form a tubular body, and pinch the upper end with a pinch roll to form a certain amount of air therein. This is a method in which a film is blown and expanded to a predetermined size (the expanded tubular body is called a "bubble"), and air is blown from the air ring to the outer periphery of the bubble to cool the film. Therefore, in the film-forming method by the inflation method, the thickness can be easily adjusted by changing the conditions of the blow ratio and the take-up speed. In the production activities, it is relatively easy to change the standard. More suitable for small lot production. Among them, as a method for forming a non-stretched polypropylene film, a T-die casting method or a downward water-cooled inflation method has hitherto been used.

[0004]

However, in the T-die casting method, there are problems that the equipment cost is higher than that of the inflation method because the equipment is large, and that it is not suitable for small lot products. In the downward water cooling inflation method,
Usually, it is suitable for forming a small width of 800 mm or less and is not suitable for forming a wide film. Further, the upward air-cooling inflation method is usually used as a molding method for an unstretched polyethylene film, but when used as a molding method for an unstretched polypropylene film, it takes time to adjust the film thickness due to low melt tension, and is manufactured. There is also a problem that it is necessary to pay close attention so that bubbles can be stably formed without causing film breakage even during film formation. Furthermore, when a polypropylene resin is formed into a film by the upward air-cooling inflation method, bubbles cannot be stably obtained, and it is difficult to adjust the film formation. Further, the polypropylene film obtained by the film formation by the upward air-cooling inflation method can use a polypropylene resin having a higher molecular weight as compared with the film formation by the T die casting method, and the film is formed in a state where the heat history is small. Therefore, it is excellent in rigidity, has less oxidative odor, and although it can be expected to improve odor and hygiene by reducing the amount of additives such as antioxidants, it has a problem of poor cold shock resistance. .

[0005]

In order to solve the above-mentioned problems, the inventors of the present invention have conducted extensive studies and as a result, as a result, a polypropylene film formed by inflation molding has a cold impact resistance, a low temperature sealability, It has excellent rigidity and
Film appearance (transparency), heat resistance, chemical resistance, oil resistance,
We have found a polypropylene film with excellent aroma retention, adjustment of seal strength (easy peeling), mechanical suitability, and economic efficiency, a laminate using it, packaging containers, and packaging containers that can also be used for retorts. . The present invention relates to a polypropylene film comprising a resin composition containing 50 to 97% by weight of a polypropylene resin and 3 to 50% by weight of an α-olefin copolymer, which is formed by air-cooled inflation molding. is there. Further, in the above, the α-olefin copolymer is an ethylene-propylene copolymer, an ethylene-1 butene copolymer, a propylene-ethylene copolymer, a propylene-1 butene copolymer, a 1-butene-ethylene copolymer. It is possible to provide a polypropylene film comprising a polymer and at least one resin selected from the group of butene-propylene copolymers. Further, the polypropylene resin, and
Melt flow rate of α-olefin copolymer (230
℃, load 2.16kg), each 0.1-5.0g
It is possible to provide a polypropylene film characterized by being / 10 minutes and 0.5 to 10.0 g / 10 minutes. In addition, at least one layer made of the above resin composition is used.
It is possible to provide a polypropylene film including layers, which is formed by a multilayer inflation molding film formation.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be specifically described below. FIG. 1 is a cross-sectional view showing an example of the multilayer laminated polypropylene film of the present invention. As shown in FIG. 1, the multilayer laminated polypropylene film according to the present invention includes a resin layer formed of a polypropylene resin containing no α-olefin copolymer, and a resin layer formed of a propylene resin and an α-olefin copolymer. and a resin layer formed of a polypropylene resin containing no α-olefin copolymer.

First, in the present invention, the polypropylene film according to the present invention is not particularly limited. For example, specifically, the polypropylene resin in the present invention includes propylene homopolymer and propylene-ethylene block copolymer. A polypropylene resin such as a polymer or a propylene-ethylene random copolymer can be used. The polyolefin resins listed above can be used in appropriate combination of two or more kinds. Further, by selecting a single site catalyst, syndiotactic polypropylene or isotactic polypropylene can be used as the propylene homopolymer, and the syndiotacticity may be adjusted. The single-site catalyst has a characteristic that the active sites are uniform (single site), and examples thereof include a metallocene catalyst (so-called Kaminsky catalyst) and a Brookhart catalyst. Specifically, it is a catalyst composed of a metallocene-based transition metal compound and an organoaluminum compound, which is sometimes used by being supported on an inorganic substance. In the above, as the metallocene-based transition metal compound, for example, a transition metal selected from Group IVB, for example, titanium (Ti), zirconium (Zr), hafnium (H
1 or 2 are attached to f) a cyclopentadienyl group, a substituted cyclopentadienyl group, an indenyl group, a substituted indenyl group, a tetrahydroindenyl group, a substituted tetrahydroindenyl group, a fluorenyl group or a substituted fluorenyl group. Or, these two groups are linked by a covalent cross-link, and in addition, a hydrogen atom, an oxygen atom, a halogen atom, an alkyl group, an alkoxy group, and
Group, acetylacetonate group, carbonyl group, nitrogen molecule, oxygen molecule, Lewis base, substituent containing a silicon atom,
Examples thereof include those having a ligand such as unsaturated hydrocarbon.

The melt flow rate (MFR) of the polypropylene resin according to the present invention is preferably 0.1 to 5.0 g / 10 minutes at 230 ° C. and a load of 2.16 kg, and 0.5 to 2.0 g / 10. The amount is desirable because it is easy to perform inflation molding. Further, for bubble stability, it is desirable that a part or the whole of the polypropylene resin is modified so that the melt tension is improved, so that the inflation molding process is easy. Specifically, for example, DOW CHEMICA
L) The trade name “INSPIRE” manufactured by the company can be used.

The α-olefin copolymer according to the present invention is specifically an ethylene-propylene copolymer,
A resin selected from the group consisting of ethylene-1 butene copolymer, propylene-ethylene copolymer, propylene-1 butene copolymer, 1-butene-ethylene copolymer and 1-butene-propylene copolymer is preferable. These α-olefins may be used alone or in combination of two or more. Among them, an ethylene α-olefin copolymer obtained by copolymerizing ethylene and α-olefin is preferable. As the ethylene α-olefin copolymer,
Specific examples include ethylene-propylene copolymer and ethylene-1 butene copolymer. Above ethylene α-
The olefin copolymer can be finely dispersed in a polypropylene resin and can have a very low glass transition point (Tg) of −50 ° C. or lower, thereby improving impact resistance even at low temperatures. Have advantages. For this reason, in holding and distributing a package of refrigerated / frozen foods, and also with respect to foods that are distributed at room temperature in winter, there is an advantage of preventing cracking due to impact and avoiding liquid leakage and the like. In addition, when a sealant layer is formed using an ethylene α-olefin copolymer, it is possible to impart the property that low-temperature heat sealability is possible, prevent pinholes from occurring, and prevent poor sealing and liquid leakage. It is possible to avoid such problems. In addition, when the sealant layer is formed by using the ethylene α-olefin copolymer, it is possible to impart easy peeling property and make it easy to open.

The melt flow rate of the α-olefin copolymer (230 ° C., load 2.16 kg) is 0.5.
~ 10.0 g / 10 min is preferable, 1.0-7.0 g /
10 minutes is desirable because it is easy to perform inflation molding. Within the above melt flow rate range, the polypropylene film according to the present invention has a form in which the α-olefin copolymer block is uniformly finely dispersed or compatible with polypropylene. The polypropylene film is preferable because the polypropylene film is compatible with the α-olefin copolymer block and has excellent cold shock resistance. Melt flow rate is 0.5 g /
If it is less than 10 minutes, film breakage will occur when the film is molded, and a smooth film cannot be obtained, which is not preferable. If the melt flow rate exceeds 10.0 g / 10 minutes, the α-olefin copolymer block has an island-like structure in which islands are dispersed in polypropylene, which makes film formation difficult and
It is not preferable because it has poor seal strength and cold shock resistance. Further, since the oil and fat component easily penetrates, when used as a container, the oil and fat component of the contents penetrates into the container, which is not preferable.

The polypropylene film according to the present invention is composed of a polypropylene resin and an α-olefin copolymer.
The α-olefin copolymer is preferably 3 to 50% by weight, and more preferably 10 to 20% by weight. In the case of the above mixing ratio, the polypropylene film according to the present invention is preferable because the polypropylene film is compatible with the α-olefin copolymer block and is excellent in cold shock resistance. 3% by weight of α-olefin copolymer
If it is less than the above range, the effect of adding the α-olefin copolymer is not recognized, which is not preferable. On the other hand, when the weight% of the α-olefin copolymer exceeds 50% by weight, the inflation molding process becomes insufficient, which is not preferable. α-
As the olefin copolymer, specifically, for example, a trade name “Toughmer” manufactured by Mitsui Chemicals, Inc. can be used.

The polypropylene resin of the present invention and α-
The olefin copolymer may contain one kind or two or more kinds of known fillers, additives and the like, if necessary, as long as the object of the present invention is not impaired. For example, the filler may contain talc, barium sulfate, calcium carbonate (amorphous, cubic, spindle-shaped), gypsum, carbon black, titanium oxide, quartz powder and the like. Also,
As additives, heat stabilizers, lubricants, anti-blocking agents, surface treatment agents, dispersants, antioxidants, ultraviolet rays, absorbers, antistatic agents, weather resistance agents, flame retardants, colorants and the like may be contained. it can.

The polypropylene resin according to the present invention has α-
When adding the olefin copolymer, the respective components are blended in a predetermined amount, the resin pellets are dry-blended in advance with a ribbon blender, a V-type blender or the like, and uniformly mixed with a kneader to obtain a powdery or granular composition. Can be

The polypropylene film according to the present invention also includes a multilayer film having at least one layer and a polypropylene resin composition layer obtained by adding an α-olefin copolymer to the above polypropylene resin. For example, the polypropylene resin composition layer in which the α-olefin copolymer is added to the polypropylene resin may be provided on both sides or one side of the polypropylene resin layer not containing them. Conversely, a polypropylene resin layer containing no α-olefin copolymer may be provided on both sides or one side of the polypropylene resin composition layer containing the α-olefin copolymer.

The content of the layer comprising the polypropylene resin and the α-olefin copolymer in the multi-layer laminated polypropylene film is preferably 50% by weight or more based on the total weight. Specifically, for example, a film configuration composed of 20% by weight of a polypropylene resin layer / 60% by weight of a mixed resin layer of a polypropylene resin and an α-olefin copolymer / 20% by weight of a polypropylene resin layer is preferable. The thickness of the monolayer film according to the present invention and the polypropylene film of the multilayer laminated film is 20 to 120 μm.
m is usually preferable because it can be easily processed into a film.

The polypropylene film forming method according to the present invention can be made into a molded product by a film forming method by an upward inflation method using an air cooling system.
When the polypropylene film according to the present invention is a monolayer film, one extruder and a monolayer circular die are used.

In the present invention, the polypropylene film produced as described above is gradually cooled by air cooling, so that the resin is uniformly crystallized, the rigidity is excellent, there is no film odor, and there is no antioxidant. Since it can be molded and processed with a small amount of additives, it is excellent in hygiene. Furthermore, by containing an α-olefin copolymer, it is excellent in cold impact resistance, low temperature heat sealability, and easy peeling. .

Since the above-mentioned resin film or sheet is excellent in rigidity, a metal such as aluminum or an inorganic substance such as aluminum, alumina oxide or silicon oxide is vapor-deposited and used on the surface thereof. You can

As a method of forming a metal thin film layer on the polypropylene film according to the present invention, for example, a physical vapor deposition method (Physical Vapor method) such as a vacuum vapor deposition method, a sputtering method or an ion plating method is used.
Deposition method, PVD method) or chemical vapor deposition methods such as plasma chemical vapor deposition method, thermochemical vapor deposition method, photochemical vapor deposition method (Chemical Vapo method)
r Deposition method, CVD method) and the like. In the present invention, when a film for forming a metal thin film layer is manufactured, a vacuum vapor deposition method is mainly used, and a plasma chemical vapor deposition method is also partially used.

Next, as a specific example of the method for forming the metal thin film layer on the polypropylene film, there is a vacuum vapor deposition method. The vacuum deposition method will be specifically described below.

As an example of the apparatus for the above vacuum vapor deposition method,
A roll-up type vapor deposition machine can be used. In the above-mentioned roll-up type vapor deposition machine, the polypropylene film fed from the unwinding roll in the vacuum chamber passes through the coating drum into the vapor deposition chamber, where it is heated in the crucible. A vapor deposition film of metal is formed through a mask on the polypropylene film on the cooled coating drum by evaporating the vapor deposition source and further ejecting oxygen if necessary, and then vapor deposition. A polypropylene film having a metal thin film according to the present invention can be manufactured by sending a polypropylene film having a film formed therein into a vacuum chamber and winding the film on a winding roll.

In the present invention, the polypropylene film having a metal thin film produced as described above can directly form a metal or inorganic vapor deposition film on the polypropylene film without laminating a functional film. , The film can be thinned, and
It has excellent retention performance and aroma retention performance for the fragrance component contained in the contents, and by reducing the manufacturing process of laminating the vapor deposition film, it is possible to improve the production efficiency and reduce the material cost. Have.

If necessary, the film or sheet of the above resin may be subjected to surface activation treatment such as corona treatment, plasma treatment, frame treatment, or the like, if necessary. it can.

Next, the resin layer constituting the multi-layer laminated polypropylene film containing at least one polypropylene film according to the present invention will be described. First, as the material for forming the resin layer, the materials are melted by heat and fused to each other. Anything you can get. Specifically, for example, low density polyethylene resin, medium density polyethylene resin, high density polyethylene resin, linear low density polyethylene resin, propylene homopolymer, propylene-ethylene block copolymer, propylene-ethylene random copolymer, etc. Polypropylene resin, ethylene-vinyl acetate copolymer,
Ionomer-resin, ethylene-ethyl acrylate copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, methylpentene resin, a polyolefin resin such as polyethylene resin or polypropylene resin acrylic acid, methacrylic acid, Of acid-modified polyolefin resins, polyvinyl acetate resins, polyester resins, polystyrene resins, etc. modified with unsaturated carboxylic acids such as maleic acid, maleic anhydride, fumaric acid, itaconic acid, etc. It is possible to use one or more resins. The thickness of the film is 10 to 300 μm, preferably 20 to 100 μm.
The m position is desirable.

Next, in the present invention, when the polypropylene film of the present invention is used to form a packaging container, it can be laminated with a base material layer. As its basic material, a resin film or sheet having excellent properties in mechanical, physical, chemical, etc., and particularly having strength and toughness and heat resistance is used. can do. Specifically, for example, tough polyester resins, polyamide resins, polyaramid resins, polyolefin resins, polycarbonate resins, polystyrene resins, polyacetal resins, fluorine resins, etc. A resin film or sheet, or the like can be used. As the resin film or sheet, either an unstretched film or a stretched film uniaxially or biaxially stretched can be used. The thickness of the film is about 5 to 100 μm, preferably 10 to 50 μm.
The m position is desirable. If necessary, a metal such as aluminum, or an inorganic substance such as aluminum, alumina oxide, or silicon oxide may be vapor-deposited and used on these base material films. In the present invention, the base film as described above, if necessary, for example, characters,
A desired print pattern such as a figure, a symbol, a pattern, or a pattern may be subjected to front printing or back printing by a normal printing method.

In the present invention, the packaging container is usually subjected to harsh physical and chemical conditions, so that strict packaging suitability is required, and deformation prevention strength, drop impact strength, and durability are required. A material satisfying various conditions such as pinhole property, heat resistance, barrier property, sealing property, quality maintenance property, workability, hygiene property, etc. is arbitrarily selected and laminated on the polypropylene film layer according to the present invention. You may use it as a material. Specifically, for example, low density polyethylene, medium density polyethylene, high density polyethylene, linear low density polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, ionomer resin, ethylene-acrylic acid. Ethyl copolymer, ethylene-
Acrylic acid or methacrylic acid copolymer, methylpentene polymer, polybutene resin, polyvinyl chloride resin, polyvinyl acetate resin, polyvinylidene chloride resin, vinyl chloride-vinylidene chloride copolymer, poly (meth) acrylic -Based resin, polyacrylonitrile-based resin, polystyrene-based resin, acrylonitrile-styrene copolymer (AS-based resin), acrylonitrile-butadiene-styrene copolymer (ABS-based resin), polyester-based resin, polyamide-based resin, polycarbonate Resin, polyvinyl alcohol resin, saponified ethylene-vinyl acetate copolymer, fluorine resin, diene resin, polyacetal resin, polyurethane resin, nitrocellulose
Coating, polyvinylidene chloride resin, polyvinyl alcohol, a film of a resin such as saponified ethylene-vinyl acetate copolymer, or a film obtained by vapor deposition of an inorganic material such as aluminum, alumina oxide, or silicon oxide, A colorant such as a pigment may be added to the resin, and optionally, a desired additive may be added and kneaded to form a film, which is optionally selected from various colored resin films or sheets having a light-shielding property. it can. In addition, for example, a film such as cellophane, synthetic paper, or the like can be used. In the present invention, the above-mentioned film or sheet may be either unstretched or uniaxially or biaxially stretched. The thickness is arbitrary, but it can be selected from the range of several μm to 300 μm and used. Further, in the present invention, the film or sheet may be any film such as an extrusion film, an inflation film, and a coating film.

Next, in the above-mentioned present invention, a method for producing a laminated body using the above-mentioned materials will be explained. As such a method, a usual packaging material is laminated.
For example, wet lamination method, dry lamination method, solventless dry lamination method, extrusion lamination method, T-die extrusion molding method, co-extrusion lamination method, inflation method, co-extrusion method. Extrusion inflation method, etc. can be used. Thus, in the present invention, when performing the above-mentioned lamination, the film can be subjected to a pretreatment such as corona treatment, ozone treatment, frame treatment, and the like, if necessary. The adhesive resin layer according to the present invention,
For example, anchor coating agents such as polyester-based, isocyanate-based (urethane-based), polyethyleneimine-based, polybutadiene-based, organic titanium-based, or polyurethane-based, polyacrylic-based, polyester-based, epoxy-based, polyvinyl acetate Anchor-coating agents, adhesives, etc., such as adhesives for laminates, such as those of the system, cellulose type, etc. can be used.

Next, a method of making a bag or a box using the polypropylene film according to the present invention will be explained. For example, when the packaging container is a soft packaging bag made of a plastic film or the like, the above method is used. Using the polypropylene film produced in 1., the surfaces of the sealant resin layer of the inner layer are opposed to each other, and they are folded, or two of them are overlapped, and further the peripheral end thereof is heat-sealed. A bag can be constructed by providing a seal portion. Then, as the bag making method, the above laminated body is
The inner layers are bent so that their surfaces are opposed to each other, or two of them are overlapped with each other, and the peripheral end portion of the outer periphery thereof is, for example, a side seal type, a two-way seal type, a three-way seal type, a four-way type. Seal type, envelope-sealed seal type, palm-sealed seal type (pyro-seale type), pleated seal type, flat bottom seal type, square bottom seal type, etc. Depending on the form of heat seal, heat seal
Then, various forms of packaging containers according to the present invention can be manufactured. In addition, for example, it is possible to manufacture self-supporting packaging bags (standing pouches),
Further, in the present invention, a tube container or the like can be manufactured using the above-mentioned laminated material. In the above, as the heat seal method, for example, known are bar seal, rotary roll seal, belt seal, impulse seal, high frequency seal, ultrasonic seal and the like. Can be done by the method. In the present invention, a spout such as a one-piece type, a two-piece type, or the like, or a zipper for opening and closing can be optionally attached to the packaging container as described above.

In the present invention, the packaging container manufactured as described above can seal a very wide range of contents, can be retort sterilized, and can be stored frozen. Filling the above packaging container, examples of contents particularly suitable for sealing, curry, retort foods such as stew,
Liquid or viscous substances such as seasonings such as miso, kneaded products such as konjac, chikuwa, and kamaboko, smoked products such as ham and sausage, cooked foods such as meatballs and hamburgers, processed marine products, pickles, boiled fish, and spices. Food and drink liquid or viscous food and drink, potion pack milk, gum syrup, pudding, jelly, milk drink, cosmetics, toiletry products such as shampoo, Ringer's solution, pharmaceuticals such as glucose,
Others.

In the present invention, the polypropylene film produced as described above has heat resistance, cold impact resistance, low temperature heat sealability, suitability for filling and packaging, resistance to contents, low odor, printing process, bag making or making. Excellent in post-processing suitability such as box processing, molded as a container manufactured as described above, filled and packaged with the above contents, for example, even under severe environment such as heat treatment, retort treatment, freezing treatment It is possible to obtain an excellent packaging product that can withstand.

[0031]

The present invention will be described in more detail with reference to specific examples. (Example 1) Ethylene-propylene block copolymer (trade name "INSPIRE114" manufactured by Dow Chemical Co., Ltd.)
Density = 0.899, melt flow rate, MFR =
0.5 g / 10 min) 90% by weight and ethylene-1 butene copolymer (trade name “Tufmer A108” manufactured by Mitsui Chemicals, Inc.
5 ", melt flow rate, MFR = 2.3 g / 10
Min) 10% by weight of two kinds of resins were used to perform film formation by an upward air-cooling inflation molding method to produce a polypropylene film of the present invention having a thickness of 70 μm. Next, one side of the polypropylene film produced above was subjected to corona treatment. (Film forming machine) Small 3 type 3-layer inflation film forming machine manufactured by Plastic Engineering Laboratory (film forming condition) Extrusion temperature: 230 ° C Die outer diameter: 75φ Die lip width: 1.2mm Blow ratio: 2.23 Take-off speed: 5m / Min

(Example 2) As an outer surface layer and an innermost layer of a bubble, an ethylene-propylene block copolymer (trade name "INSPIRE114" manufactured by Dow Chemical Co., Ltd. density = 0.899, melt flow rate, MFR = 0). 0.5 g
/ 10 minutes) 100% by weight, and the same resin layer as in Example 1 as an intermediate layer, ethylene-propylene block copolymer (trade name “INSPIRE11 manufactured by Dow Chemical Co., Ltd.”
4 ") 65% by weight and ethylene-butene-1 copolymer (trade name" Tufmer A108 "manufactured by Mitsui Chemicals, Inc.)
5 ", melt flow rate, MFR = 2.3 g / 10
Min) 35% by weight of two kinds of resins, the same film forming machine as in Example 1 was used to perform film formation by an upward air-cooling inflation molding method to form a film having a thickness of 70 μm, A polypropylene film having a layer structure was produced. Layer constitution: Resin layer 14 μm composed of ethylene-propylene block copolymer / resin layer 42 μm composed of a mixture of ethylene-α-olefin copolymer and ethylene-propylene block copolymer / resin composed of ethylene-propylene block copolymer Layer 14 μm Next, one side of the polypropylene film produced above was subjected to corona treatment. (Film forming conditions) Extrusion temperature: 230 ° C. Die outer diameter: 75φ Die lip width: 1.2 mm Blow ratio: 2.23 Take-off speed: 5 m / min

(Example 3) Propylene copolymer (trade name "INSPIRE 112" manufactured by Dow Chemical Co., Ltd. density =
0.9, melt flow rate, MFR = 0.4 g / 10
Min) 60% by weight and 1-butene-propylene copolymer (trade name “Tufmer BL2481” manufactured by Mitsui Chemicals, Inc.)
Using 40% by weight of two kinds of resins, using the same film forming machine as in Example 1, and under the same film forming conditions as in Example 1, film forming molding was performed by an upward air-cooling inflation molding method, A 50 μm thick polypropylene film was produced. Next, one side of the polypropylene film produced above was subjected to corona treatment. (Film forming conditions) Extrusion temperature: 230 ° C. Die outer diameter: 75φ Die lip width: 1.2 mm Blow ratio: 2.23 Take-off speed: 5 m / min

Comparative Example 1 Ethylene-propylene block copolymer (trade name "INSPIR" manufactured by Dow Chemical Co., Ltd.
E114 "density = 0.899, melt flow rate,
MFR = 0.5 g / 10 min)
Using the same film forming machine as in Example 1, under the same film forming conditions as in Example 1, film formation was carried out by an upward air-cooled inflation molding method to produce a polypropylene film having a thickness of 70 μm. Next, one side of the polypropylene film produced above was subjected to corona treatment. (Film forming conditions) Extrusion temperature: 230 ° C. Die outer diameter: 75φ Die lip width: 1.2 mm Blow ratio: 2.23 Take-off speed: 4 m / min

(Comparative Example 2) Ethylene-propylene block copolymer (trade name "Chisopolypro" manufactured by Chisso Petrochemical Co., Ltd.) Density = 0.9, melt flow rate, M
FR = 8.0 g / 10 minutes) 90% by weight, ethylene-1
Butene copolymer (trade name “Tufmer A40” manufactured by Mitsui Chemicals, Inc.
85 ", melt flow rate, MFR = 6.7 g / 10
Min) using 10% by weight of two kinds of resins, using the same film forming machine as in Example 1 and under the same film forming conditions as in Example 1 by an upward air-cooling inflation molding method to form a film by molding. However, the bubbles were not stable and the polypropylene film could not be formed into a film.

(Comparative Example 3) Ethylene-propylene block copolymer (trade name "INSPIR" manufactured by Dow Chemical Co., Ltd.
E114 "density = 0.899, melt flow rate,
MFR = 0.5 g / 10 min) 45 wt%, ethylene-
1-butene copolymer (trade name “Tufmer A” manufactured by Mitsui Chemicals, Inc.
1085 ", melt flow rate, MFR = 2.3 g /
10 minutes) 55% by weight of two kinds of resins are used, the same film forming machine as in Example 1 is used, and the same film forming conditions as in Example 1 are used.
Film formation was carried out by an upward air-cooled inflation molding method, but the bubbles were not stable and a polypropylene film could not be formed. (Film forming conditions) Extrusion temperature: 230 ° C. Die outer diameter: 75φ Die lip width: 1.2 mm Blow ratio: 2.23 Take-off speed: 5 m / min

(Comparative Example 4) Propylene copolymer (trade name "INSPIRE112" manufactured by Dow Chemical Co., Ltd. density =
0.900, melt flow rate, MFR = 0.4 g /
10 minutes) Using 100% by weight of one kind of resin, using the same film forming machine as in Example 1, under the same film forming conditions as in Example 1,
Film formation was carried out by an upward air-cooled inflation molding method to produce a polypropylene film having a thickness of 50 μm. Next, one side of the polypropylene film produced above was subjected to corona treatment. (Film forming conditions) Extrusion temperature: 230 ° C. Die outer diameter: 75φ Die lip width: 1.2 mm Blow ratio: 2.23 Take-off speed: 5 m / min

(Comparative Example 5) Ethylene-propylene block copolymer (trade name "Chisopolypro" manufactured by Chisso Petrochemical Co., Ltd.) Density = 0.9, melt flow rate, M
FR = 8.0 g / 10 minutes) 90% by weight, ethylene-1
Butene copolymer (trade name “Tufmer A40” manufactured by Mitsui Chemicals, Inc.
85 ", melt flow rate, MFR = 6.7 g / 10
Min) 10% by weight of two kinds of resins are used to form a film by a T die-cast molding method to obtain a thickness of 70
A μm polypropylene film was produced. Next, one side of the polypropylene film produced above was subjected to corona treatment. (Film forming conditions) Extrusion temperature: 250 ° C. Die effective width: 250 mm Die lip width: 1.2 mm

(Comparative Example 6) Ethylene-propylene block copolymer (trade name "INSPIR" manufactured by Dow Chemical Co., Ltd.
E114 "density = 0.899, melt flow rate,
MFR = 0.5 g / 10 min) 90 wt%, ethylene-
1-butene copolymer (trade name “Tufmer A” manufactured by Mitsui Chemicals, Inc.
1085 ", melt flow rate, MFR = 2.3 g /
(10 minutes) 10% by weight of two kinds of resins were used to form a film by a T-die casting method to produce a polypropylene film having a thickness of 70 μm. next,
One side of the polypropylene film produced above was subjected to corona treatment. Film forming conditions) Extrusion temperature: 250 ° C. Effective die width: 250 mm Die lip width: 1.2 mm

(Experiment 1: Young's modulus measurement test) Example 1,
The single-layer or multi-layer polypropylene films obtained in No. 2 and Comparative Examples 1, 5, and 6 were measured according to ASTM D882.

(Experiment 2: Heat seal strength test) Example
1 and 2 and the monolayers or polylayers obtained in Comparative Examples 1, 5, and 6.
Polyester on the corona treated surface of a single layer polypropylene film
Polyurethane adhesive (Dainippon Ink and Chemicals, Inc.)
Manufactured [LX730 / KR90 = 15/1 (wt%)])
4 g / m ² (Dry state) Apply and biaxially stretch with a thickness of 15 μm
Stretched nylon film [manufactured by Mitsubishi Kagakujin Pax Co., Ltd.
Laminate [Bonille Q] by dry lamination method
To produce a laminated film.

The obtained laminated film was 130 mm × 17
Two pieces of 0 mm size were cut out, polypropylene films were placed so as to face each other, and thermocompression bonding was performed at a width of 10 mm (condition 190 ° C., 2 kg / cm ² , 1 second), and then the heat seal strength in the MD direction was measured. did. Where MD
The direction is the film feeding direction. The heat-sealing strength in the MD direction is measured by cutting out a test piece including a heat-sealing portion on the lateral side with a width of 15 mm and pulling this in the MD direction. Therefore, length 10 mm, width 1
The seal strength is measured when the 5 mm seal portion is pulled along the length direction.

The heat-sealing strength was measured with a tensile tester (manufactured by Orientec Co.) at a tensile speed of 300 mm / min. The results are shown in Table 1. In addition, in Table 1, 15
Heat seal strength per mm (Unit: g / 15mm)
Was described.

(Experiment 3: Cold Shock Resistance Test) The single-layer or multi-layer polypropylene films obtained in Examples 1 and 2 and Comparative Examples 1, 5 and 6 were cut into a size of 100 mm × 100 mm, and the test piece was held. Diameter 25.4 mm, hammer diameter 1
The energy value when punching at a speed of 5 m / sec at 0 ° C. was measured using a 2.7 mm jig.

(Experiment 4: Oil Resistance Test) The monolayer or multilayer polypropylene films obtained in Examples 1 and 2 and Comparative Examples 1, 5 and 6 were cut into a size of 100 mm × 100 mm, and the test pieces were used as edible oil. 120 ° C in the immersed state
Then, the difference in expansion coefficient (area ratio) after heating for 30 minutes was compared.

(Experiment 5: Sensory test) Single-layer or multi-layer polypropylene film of 70 μm obtained in Examples 1 and 2 and Comparative Examples 1, 5 and 6 and biaxially stretched nylon film of 15 μm thickness [Mitsubishi Kagaku Kojin Co., Ltd.] In the same manner as in Experiment 2 using a PAX Co., Ltd. [Bonyl Q], a polyester polyurethane adhesive (Dainippon Ink & Chemicals Co., Ltd. [LX730 / KR90 = 15/1 (wt%)] 4
g / m ² (dry state) was applied and laminated by a dry lamination method to prepare a laminated film. Two pieces of the laminate obtained above are cut into a size of 130 mm × 170 mm, polypropylene films are arranged so as to face each other, and thermocompression bonding (condition 190 ° C., 2 kg) / Cm ² , for 1 second) to obtain a bag.
Then, add 10 bottles of mineral water to the bag obtained above.
It was filled with 0 cc and subjected to hot water retort sterilization at 120 ° C. for 30 minutes.

A sensory test was conducted on the influence of the odorous component by the monomer component of the polypropylene film on the content (mineral water). 20 panelists evaluated each odor sterilized sample for each of the above-mentioned retort-sterilized samples by comparing it with untreated mineral water prepared separately. Was evaluated on a two-point scale of O and X. ○ indicates that almost 20 panelists have almost no change in odor,
In the case of “X”, most of the 20 panelists judged that the panel had an odor, and the film odor was shown in Table 1. (Evaluation Criteria) ○: Almost no change in odor ×: Film odor

(Results of Experiments 1 to 5)

[Table 1]

(Experiment 6: Heat Seal Temperature Test) A polyester polyurethane adhesive (Dainippon Ink and Chemicals) was applied to the corona-treated surface of the polypropylene film having a thickness of 50 μm obtained in Example 3 and Comparative Example 4 in the same manner as in Experiment 2. Co., Ltd. [LX730 / KR90 = 15/1 (wt%)] 4g / m2 (dry state) applied, thickness 15µm
The biaxially stretched nylon film of [Bonil Q manufactured by Mitsubishi Kagaku Pakto Co., Ltd.] was laminated by a dry lamination method to prepare a laminated film.

The obtained laminated film was 130 mm × 17
Cut 2 pieces into 0mm size and arrange polypropylene films so that they face each other.
00 ° C, 110 ° C, 120 ° C, 130 ° C, 140 ° C, 1
After thermocompression bonding at ² kg / cm ² for 1 second at each temperature of 60 ° C., the heat seal strength in the MD direction was measured in the same manner as in Experiment 2. The heat seal strength in the MD direction is 15 mm for the test piece including the heat seal part on the side.
It is measured by cutting out with, and pulling this in the MD direction. The heat seal strength obtained by the above measurement is 3N
The heat seal temperature of not less than / 15 mm is described in the measurement results.

(Results of Experiment 6)

[Table 2]

In the measurement results of Examples 1 and 2, there was no film odor, and good results were obtained in Young's modulus, seal strength, cold shock resistance, and oil resistance. In the measurement results of Comparative Example 1, good Young's modulus, seal strength, oil resistance, and odor were obtained, but low cold impact resistance was confirmed. In Comparative Examples 2 and 3, the bubbles were not stable and film formation could not be performed. In the measurement results of Comparative Example 5, a good seal strength was obtained, but a film odor was observed to be transferred to the contents, and it was confirmed that the Young's modulus, cold shock resistance, and oil resistance were low. In the measurement results of Comparative Example 6, good results were obtained in terms of seal strength and cold shock resistance, but film odor migration to the contents was observed, and results of low Young's modulus and oil resistance were confirmed. In the measurement result of Example 3, the sealing strength of the bag body heat-sealed at the heat-sealing temperature of 100 ° C. was 3 N / 15 mm. That is, sufficient sealing strength was obtained by low temperature heat sealing. On the other hand, in the measurement result of Comparative Example 4, the seal strength after heat sealing at a heat sealing temperature of less than 140 ° C. is 3
The strength of N / 15 mm was not obtained.

As is clear from the results of Experiments 1 to 6 shown in Tables 1 and 2, the polypropylene film of the present invention was
While maintaining seal strength, it has excellent oil resistance, high Young's modulus, and high low-temperature impact resistance, so not only is it suitable for automatic packaging, but it is also suitable for packages such as frozen foods at low temperatures. It is excellent in retention and distribution, and is a great contribution to the industry. In addition, the bag using the polypropylene film of the present invention can provide an excellent packaging product because the film odor does not transfer to the contents after retort.

[0054]

As described above, according to the polypropylene film of the present invention, since the film is formed by the air-cooling inflation method as described above, a film having excellent rigidity can be obtained, and the film is superior to conventional products. Even if the thickness is reduced, the same rigidity (waist of the film) can be obtained. In addition, the polypropylene film of the present invention has less heat history than the conventional film-forming method by the casting method, so that there is no film odor and the amount of the additive used is small, which is excellent in hygiene and by the air cooling method. Because of the cooling, a film having a high resin crystallinity can be obtained, and a film having excellent chemical resistance and oil resistance and excellent economical efficiency can be provided.
Further, the polypropylene film of the present invention, on one surface of the polypropylene film, directly, a metal such as aluminum, or, since it is possible to form a thin film layer of an inorganic material such as silicon oxide, polypropylene film alone,
It does not adsorb contents such as pharmaceuticals and cosmetics where scents and medicinal components are easily adsorbed, does not leak to the outside, has excellent retention performance for flavoring components contained in contents
Furthermore, it is possible to provide a film that does not cause a change in taste, an offensive odor, and the like, and it is possible to reduce the thickness of the film. By reducing the step of laminating the functional film, the production efficiency is improved and the material cost is reduced. It can be reduced. Further, the polypropylene film of the present invention, by mixing the α-olefin copolymer, a film having excellent impact resistance at low temperature can be obtained as compared with the conventional product, and low temperature heat sealability and adjustment of seal strength (easy) Peeling) makes it possible to maintain the quality of the contents while maintaining the appearance, suitability for machining,
It is possible to provide a packaged product excellent in holding frozen foods in a low temperature range, heat sterilization treatment at high temperature, and distribution.

[Brief description of drawings]

FIG. 1 is a sectional view showing an example of a multilayer laminated polypropylene film of the present invention.

[Explanation of symbols]

1 Resin layer formed from polypropylene resin not containing α-olefin copolymer 2 Resin layer formed from propylene resin and α-olefin copolymer 10 Multilayer laminated polypropylene film

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C08L 23/14 C08L 23/14 23/16 23/16 // B29K 23:00 B29K 23:00 B29L 7: 00 B29L 7:00 9:00 9:00 (72) Inventor Masahiro Shimoyamada 1-1-1, Ichigayakaga-cho, Shinjuku-ku, Tokyo Dai Nippon Printing Co., Ltd. F-term (reference) 4F071 AA15 AA20 AA21 AA75 AF02 AF14 AF23 AH04 BB09 BC01 4F100 AK07A AK09A AK09J AK64A AK65A AK67A AL05A AT00B BA01 BA02 EH17 JA06A YY00A 4F210 AA04E AA09 AA11 AA12E AG01 AG03 QA01 QK01 4J002 BB05X BB12W02BB17W BB12W BB13W15BB13W

Claims (4)

[Claims] 1. A polypropylene resin of 50 to 97% by weight,
A polypropylene film comprising a resin composition containing 3 to 50% by weight of an α-olefin copolymer formed by air-cooling inflation molding. 2. The α-olefin copolymer is an ethylene-propylene copolymer, an ethylene-1 butene copolymer, a propylene-ethylene copolymer, a propylene-1 butene copolymer, a 1-butene-ethylene copolymer. The polypropylene film according to claim 1, wherein the polypropylene film is at least one resin selected from the group of polymers and 1-butene-propylene copolymers. 3. The polypropylene resin and α-
Melt flow rate of olefin copolymer (230 ℃,
Load 2.16 kg), 0.1-5.0 g / 1 each
0 minutes, 0.5-10.0 g / 10 minutes, The polypropylene film in any one of Claims 1-2 characterized by the above-mentioned. 4. The polypropylene film according to any one of claims 1 to 3, which comprises at least one layer comprising the resin composition and is formed by a multilayer inflation molding film formation.