JP2009061705A - Manufacturing process of polypropylene resin laminated non-oriented film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a film which is excellent in mat feeling and fusion sealing strength and which has less curling after fusion sealing. <P>SOLUTION: The laminated film comprises at least two layers consisting of a polyolefinic resin, wherein a sealing layer contains 50 to 80 mass% of propylene random copolymer (A) and 20 to 50 mass% of ethylene-α-olefin copolymer with ≤100°C melting point and/or propylene-α-olefin copolymer resin and a printing layer contains ≥95 mass% of propylene block copolymer with ≥140°C melting point. In this manufacturing method of the polyolefinic laminated film, when the film is solidified by cooling, a surface of a sealing layer side is brought into contact with a cooling roll. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a laminated polypropylene-based unstretched film, and more specifically, because it has excellent matte feeling, fusing seal strength, and less curling at the time of bag-making by fusing seal, it is a packaging field for food such as bread and confectionery bread. It is related with the polypropylene-type lamination | stacking unstretched film suitable for.

  Polypropylene-based unstretched films are used in various packaging materials such as food packaging because they have high rigidity, good transparency and are inexpensive among sealant films. However, regarding the packaging field of foods such as bread and confectionery bread, it has been required to have excellent mat feeling and fusing seal strength.

In response to these requirements, a sealing layer made of a resin containing 50% by mass or more of a propylene-based random copolymer and a printing layer made of a propylene-based block copolymer having an ethylene content and a xylene-soluble content ratio in a specific range Furthermore, a laminated film composed of an intermediate layer has been proposed (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 2007-45050

  However, the above method has a drawback that curling at the time of bag making by fusing seal is large.

  The present invention provides a polypropylene-based laminated unstretched film suitable for the packaging field of food such as bread and confectionery bread, because it has excellent mat feeling and fusing seal strength and has little curling at the time of bag making by fusing seal. is there.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have produced a polypropylene-based laminated presence / absence stretched film that is excellent in mat feeling and fusing seal strength and has little curling during bag-making by fusing seal. It was completed.

That is, the present invention is a method for producing a laminated film composed of at least two layers of a polyolefin resin, a seal layer and a printed layer, wherein each of the layers has the following characteristics: In the method for producing a polyolefin-based laminated film, the surface of the sealing layer is brought into contact with a cooling roll when the laminated film is cooled and solidified.
(1) Seal layer The propylene random copolymer (A) is 50 to 80% by mass, and the ethylene-α / olefin copolymer bag (B) having a melting point of 100 ° C. or lower is 20 to 50% by mass.
(2) The printing layer comprises a resin composition containing 95% by mass or more of a propylene-based block copolymer (D) having a melting point of 140 ° C. or higher.

  In this case, it is preferable to add 3000 to 8000 ppm of an antistatic agent containing at least an alkyl sulfonate to the printed layer.

  In some cases, it is preferable that an intermediate layer mainly composed of a propylene-based block copolymer (D) having a xylene-soluble content ratio at 20 ° C. of 6 to 25% is provided between the sealing layer and the printing layer. It is.

Furthermore, in this case, the thickness ratio of the sealing layer is 10 to 30% of the whole, The method for producing a polyolefin-based resin laminated film,
Furthermore, according to the above method, there is provided a method for producing a laminated film composed of at least two layers of a polyolefin resin, that is, a seal layer and a print layer, wherein each of the layers has the following characteristics and the thickness ratio of the seal layer is 10 %, And a suitable film called a polyolefin-based resin laminate film having a height of less than 3 mm according to the following measurement is obtained.
(1) Seal layer A resin composition comprising 50 to 80% by mass of the propylene random copolymer (A) and 20 to 50% by mass of an ethylene-α / olefin copolymer bag (B) having a melting point of 100 ° C. or less. .
(2) Printing layer It consists of a resin composition containing 95% by mass or more of a propylene-based block copolymer (C) having a melting point of 140 ° C. or higher.
(Measuring method)
The film was folded in two so that the sealing surfaces face each other and one film was 5 cm long, and supplied to an automatic bag making machine (PP5500 type manufactured by Kyoei Printing Machinery Co., Ltd.). And the temperature of the fusing seal blade (blade edge angle 60 degrees) is set at 300 ° C., the bag is made at a bag making speed of 100 bags / minute, and the bag is obtained by placing it horizontally with one side of the film on the bottom. The raised height was measured with a gauge.

  The polypropylene laminated laminated stretched film of the present invention is excellent in matte feeling, fusing seal strength, and has little curling during bag making by fusing seal, so it can be used in a wide range of packaging fields for foods such as bread and confectionery bread and other articles. Can do.

  The present invention is a laminated polypropylene-based unstretched film comprising at least two layers of a seal layer and a print layer.

The resin used for the laminate layer and seal layer will be described below.
(Seal layer)
The seal layer of the present invention comprises 50 to 80% by mass of the propylene random copolymer (A) and 20 to 50% by mass of an ethylene-α / olefin copolymer bag (B) having a melting point of 100 ° C. or less. Use of a resin composition is preferable in terms of fusing and sealing properties.

  The propylene random copolymer (A) is a propylene / α-olefin random copolymer resin having an α-olefin content in the range of 2 to 8% by mass. The content of α-olefin is more preferably 3 to 7% by mass, and further preferably 3 to 6% by mass. When the α-olefin content is less than 2% by mass, the fusing and sealing properties are poor, and when it exceeds 8% by mass, the blocking resistance is deteriorated. Examples of the α-olefin include ethylene, 1-butene, 1-hexene, 4-methyl / 1-pentene, 1-octene and the like.

In these, the random copolymer with ethylene and / or 1-butene is preferable. The MFR is not particularly limited as long as it can be made into a film, but is usually in the range of 0.5 to 20 g / 10 minutes, preferably 2 to 10 g / 10 minutes, particularly preferably 5 to 10 g / 10 minutes. It is in the range. Moreover, it is preferable that melting | fusing point is 120 degreeC or more.
The propylene / α-olefin copolymer (A) according to the present invention usually has a molecular weight distribution (expressed by a ratio of the weight average molecular weight Mw and the number average molecular weight Mn) in the range of 1.5 to 3. Is preferred. When it exceeds 3, low molecular weight substances increase and blocking resistance deteriorates. Therefore, it is preferable to polymerize using a single site catalyst.

  The propylene / α-olefin copolymer (B) is obtained by polymerizing two or more selected from α-olefin monomers having 2 to 10 carbon atoms such as ethylene, butene, pentene, hexene, octene, and decene. Polypropylene random copolymers or block copolymers are preferred, and these copolymers can be used alone or in admixture.

The comonomer is preferably contained in an amount of 20 to 40% by mass, and preferably has a melt flow rate of 1 to 8 g / 10 min and a density of 0.850 to 0.910 / cm ³ .
(Print layer)
For the printed layer of the present invention, a resin composition containing 95% by mass or more of a propylene-based block copolymer (C) having a melting point of 140 ° C. or higher is used.
When the content of the propylene-based block copolymer (C) is less than 95% by mass, curling after bag making by fusing sealing becomes large.

The propylene block copolymer (C) is a propylene / α-olefin block copolymer resin having an α-olefin content of preferably 2 to 10% by mass, more preferably 4 to 8% by mass. When the α-olefin content is less than 2% by mass, the impact resistance is inferior, and when it exceeds 8% by mass, the transparency and rigidity are deteriorated. Examples of the α-olefin include ethylene, 1-butene, 1-hexene, 4-methyl / 1-pentene, 1-octene and the like. In these, ethylene and / or 1-butene are preferable. The MFR is not particularly limited as long as it can be a film, but is usually in the range of 0.5 to 10 g / 10 minutes, preferably 1 to 5 g / 10 minutes. When the MFR is less than 0.5 g / 10 min, the productivity is inferior, and when it exceeds 10 g / 10 min, the impact resistance is inferior.
The propylene-based block copolymer (C) has a xylene-soluble fraction ratio at 20 ° C. of 10 to 30%, an ethylene content of 8 to 20% by mass, a melt flow rate of 2 to 8 g / 10 min, and a melting point of 150. The thing of -200 degreeC is preferable.
In particular, if the ratio of the xylene soluble part at 20 ° C. is less than 10%, there is a problem that the film is easily torn, and if it exceeds 30%, the rigidity of the film is lowered.

The printing layer preferably contains 3000 to 8000 ppm of an antistatic agent containing at least an alkyl sulfonate with respect to the resin composition.
For example, it is preferable to add 30000-70000 ppm of erucic acid amide, glycerin fatty acid ester, sodium alkyl sulfonate and the like.

It is heat to have an intermediate layer made of a resin composition mainly composed of a propylene-based block copolymer (D) having a xylene-soluble fraction ratio of 6 to 25% at 20 ° C. between the sealing layer and the printing layer. It is preferable in terms of seal strength.
The ethylene content is preferably 8 to 20% by mass, the ratio of the xylene soluble part at 20 ° C. is 20 to 30%, the melt flow rate is 2 to 8 g / 10 min, and the melting point is preferably 150 to 200 ° C. .
The propylene block copolymer (D) in the above range may be a mixture of two or more propylene block copolymers in the above range.

  In the present invention, it is preferable that the ratio of the xylene-soluble portion at 20 ° C. contained in the printed layer, the intermediate layer, and the seal layer is increased in the order of seal layer <intermediate layer <print layer. It is possible to balance various characteristics.

Usually used antioxidants, weathering stabilizers, antistatic agents, antifogging agents, antiblocking agents, lubricants, nucleating agents are used in the sealing layer, printing layer, and intermediate layer of the present invention as long as the object of the present invention is not impaired. In addition, additives such as pigments or other polymers can be blended as necessary. In particular, the sealing layer contains various known anti-blocking agents such as inorganic compound particles such as silica, talc, zeolite and aluminum borate, and organic compound particles such as polymethyl methacrylate, melamine formalin resin, melamine urea resin and polyester resin. Addition of 0.01 to 1% by mass is preferable because a film having further improved anti-blocking properties can be obtained. Among these, pulverized silica, spherical silica, and polymethyl methacrylate are particularly preferable in terms of antiblocking properties and transparency.
These average particle diameters are preferably from 2 to 8 μm, and preferably from 50000 to 15000 ppm.

  Also, 0.01 to 0.5% by mass of various known slip agents such as hydrocarbon, fatty acid, higher alcohol, aliphatic amide, metal soap, ester, etc. are added to the seal layer. It is preferable that a film with improved slip properties is obtained. Among these, when a combination system of erucic acid amide with immediate effect and delayed-acting behenic acid amide is used, stability of winding of the film at the time of film formation by subsequent erucic acid amide and subsequent cutting processing, printing The workability of the laminate can be improved, while the slow-acting behenic acid amide that is difficult to be adsorbed by the adhesive can improve the slipperiness and antiblocking properties after dry lamination.

  Further, in the sealing layer, high density polyethylene, dibenzylidene sorbitol, methyl substituted dibenzylidene sorbitol, hydroxy-di-aluminum, bissorbicyl, bis-sodium methylene bis-acid phosphate sodium Adding 0.01 to 1.0% by weight of various known crystallization nucleating agents such as salt suppresses the occurrence of roll marks during film formation and improves the slip and blocking properties immediately after the film formation. Since the obtained film is obtained, it is preferable. Among these, the use of a polyethylene crystallization nucleating agent that is relatively easy to add and has no problem with odor can improve the quality and processability immediately after the film forming process in a well-balanced manner.

  It is preferable to add 0.01 to 1% by mass of various known anti-blocking agents in the printed layer because a film with improved anti-blocking property of the film product roll can be obtained.

In addition, as a method for adding these additives and polymers, a method of directly feeding into an extruder at the time of film formation is also possible, but a masterbatch using the polymer used in the present invention as a base resin is prepared in advance. A method of feeding this master batch into an extruder during film formation is preferred.
The antistatic agent master batch is prepared by blending 10-30% of the antistatic agent with the polypropylene resin.

  The manufacturing method of said resin (A)-(E) concerning this invention is not limited. It can be produced by various known methods, for example, using a Ti-based Ziegler catalyst whose main component is Ti, Mg, Cl or the like. However, as described above, the propylene / α-olefin random copolymer resin (A) is particularly preferably a resin produced using a single site catalyst. The single site catalyst is a catalyst having a uniform active site (single site), and examples thereof include a metallocene catalyst (so-called Kaminsky catalyst) and a Brookhart catalyst. For example, a metallocene catalyst is a catalyst comprising a metallocene transition metal compound, at least one compound selected from the group consisting of an organoaluminum compound and a compound that forms an ion pair by reacting with the metallocene transition metal compound, and an inorganic substance. It may be carried on.

In a propylene / α-olefin random copolymer resin, it is common to increase the content of α-olefin in order to lower the sealing start temperature. However, when the content of α-olefin is increased, the film becomes soft and the blocking resistance is deteriorated.
On the other hand, the molecular weight distribution of the resin (expressed by the ratio of the mass average molecular weight Mw to the number average molecular weight Mn) increases the molecular weight distribution as the value increases, so the low molecular weight product increases and the blocking resistance deteriorates. To do. Therefore, in order to balance low-temperature heat sealability and blocking resistance, it is effective to narrow the molecular weight distribution of the resin and reduce low molecular weight products. In order to narrow this molecular weight distribution, it is effective to perform polymerization using a single site catalyst having uniform activity.

  Although the thickness of the laminated propylene-based unstretched film of the present invention is variously determined depending on the application, it is usually in the range of 10 to 500 μm, preferably 20 to 100 μm. Moreover, as for the thickness ratio of each layer, it is desirable that the ratio of the two-layer type sealing layer is 5 to 40% and the ratio of the printing layer is 60 to 95%. Furthermore, it is more desirable that the ratio of the sealing layer is 10 to 30% and the ratio of the lamellar layer is 70 to 90%.

  If the thickness ratio of the seal layer is less than 10%, the fusing sealability is lowered, which is not preferable. Conversely, if it exceeds 40%, blocking resistance and film rigidity are lowered, which is not preferable.

  In the case of the three-layer type, the thickness ratio of each layer is preferably 5 to 40% for the seal layer, 30 to 80% for the intermediate layer, and 10 to 30% for the lami layer. Further, the ratio of the seal layer is more preferably 10 to 30%, the ratio of the intermediate layer is 40 to 70%, and the ratio of the laminated layer is more preferably 10 to 30%.

  If the thickness ratio of the seal layer is less than 10%, the heat sealability is lowered, which is not preferable. Conversely, if it exceeds 40%, blocking resistance and film rigidity are lowered, which is not preferable.

  If the thickness ratio of the intermediate layer is less than 30%, the rigidity of the film decreases, which is not preferable. On the other hand, if it exceeds 80%, the fusing and sealing properties deteriorate, which is not preferable.

  When the thickness ratio of the printing layer is less than 10%, blocking resistance and film rigidity are lowered. Conversely, if it exceeds 30%, the transparency deteriorates, which is not preferable.

Specifically, the laminated propylene-based unstretched film of the present invention can employ a film forming method such as a T-die method. In addition, such laminated films may be individually laminated after film formation, but the method of film formation by coextrusion using a multilayer die having a two-layer structure is most preferable. Examples of the method for co-extrusion film formation include lamination using a feed block and a method using a multi-manifold die.
For example, a polymer and an additive are blended, extruded by a three-layer T-die coextrusion cast molding machine, and cooled and solidified so that the sealing surface is in contact with the cooling roll, and the total film thickness and the thickness of each layer are within the above ranges. To form a three-layer film.
In particular, the shrinkage stress of each film layer can be optimized by cooling and solidifying the sealing surface in contact with the cooling roll.
The die outlet resin temperature is preferably 240 to 260 ° C for the sealing layer and the printing layer, 250 to 270 ° C for the intermediate layer, and 30 ° C or less for the temperature of the cooling roll.
As a result, it is possible to obtain a film having excellent fusing seal strength and less curling during bag making by fusing seal.

In the polyolefin resin laminated film of the present invention, it is preferable that the height measured by the following measurement is less than 3 mm.
(Measuring method)
The film was folded in two so that the sealing surfaces face each other and one film was 5 cm long, and supplied to an automatic bag making machine (PP5500 type manufactured by Kyoei Printing Machinery Co., Ltd.). And the temperature of the fusing seal blade (blade edge angle 60 degrees) is set at 300 ° C., the bag is made at a bag making speed of 100 bags / minute, and the bag is obtained by placing it horizontally with one side of the film on the bottom. The raised height was measured with a gauge.

  The laminated propylene-based unstretched film of the present invention is subjected to an oxidation treatment by corona treatment, flame treatment, plasma treatment, or the like on the side surface of the laminated layer in order to improve the printability or adhesion to other films. A surface activation treatment such as a coating treatment may be performed.

The film obtained by the method of the present invention is folded in two so that the sealing surfaces face each other and one film is 5 cm long, and then fusing and bag-making are performed in the same manner as above. It was. The resulting bag film is placed horizontally with one side down and the height of the film is less than 3 mm.
This makes the appearance after bag making very excellent.

In the present invention, it is preferable that the heat resistance when the sealing layers are heat sealed at 80 ° C. is 0.3 N / 70 mm or more.
Furthermore, it is preferable that the heat resistance when heat-sealed at 90 ° C. is 0.3 to 3.0 N / 70 mm.

  In the present invention, the fusing seal strength when fusing and sealing at 300 ° C. is preferably 15 N / 15 mm or more, and more preferably 17 N / 15 mm or more.

  The laminated propylene-based unstretched film of the present invention obtained by the above method may be used alone as various packaging materials, but is preferably used in the packaging field of foods such as bread and confectionery bread.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited by the following examples, but may be implemented with appropriate modifications within a scope that can meet the gist of the present invention. It is also possible to do.

  The measurement and evaluation methods employed in this specification are as follows.

[MFR (melt flow rate)]
According to the 2004 edition of JISK7210, it was measured by the method of Condition-14 (load 2.16 kg, temperature 230 ° C.).

[Melting point]
About 6 mg of the propylene-based copolymer (C) is weighed and heated to 200 ° C. at a rate of temperature increase of 10 ° C./min using a differential scanning calorimeter (Tyf 5200) manufactured by Seiko Electronics Co., Ltd. After holding at 5 ° C. for 5 minutes, the temperature lowering rate was cooled to 0 ° C. at 100 ° C./min, and the melting curve was measured again when the temperature raising rate was raised from 0 ° C. to 200 ° C. at 10 ° C./min, From this melting curve, the method of J1S-K-71219.1 was followed, and the temperature at the top of the melting peak on the highest temperature side was melted from the melting curve.

[Ratio of xylene soluble part at 20 ° C. (%)]
After 5 g of the sample was completely melted in 500 ml of boiling xylene, the temperature was lowered to 20 ° C. and left for 4 hours or more. Thereafter, the precipitate and the solution were separated by filtration, and the filtrate was dried and dried at 70 ° C. under reduced pressure. From the weight of the obtained dried product, the 20 ° C. xylene-soluble part amount was measured and the ratio was determined.

[Ethylene content]
It was measured by 13C-NMR method according to the method described on page 616 of Polymer Handbook (1995, published by Kinokuniya Shoten).

[Haze]
In accordance with the 2004 edition of JIS-K-6714, the measurement was performed using “Heisez Tester J” manufactured by Toyo Seiki Seisakusho.

[Heat seal strength]
Using a heat sealer (PP-701-B) manufactured by Tester Sangyo Co., Ltd., the width direction of the heating bar is fixed at a lower bar temperature of 80 ° C. in a direction orthogonal to the flow direction of the film, and sealed at 0.1 MPa × 3 seconds, The peel strength was measured at a width of 70 mm to obtain the heat seal strength.

[Fusing seal strength]
Prepare two film rolls, pull out each film and set it so that the sealing faces of the film face each other, and then fold it in two to an automatic bag making machine (PP5500 model made by Kyoei Printing Machinery Materials Co., Ltd.) Supplied. Then, sealing and bag making were performed at a temperature setting of 300 ° C. with a fusing seal blade (blade edge angle of 60 degrees) and a bag making speed of 100 bags / min. Then, the seal portion was cut out to a width of 15 mm, two films were attached to the upper and lower chucks of Tensilon, and the fusing seal strength between the printing surfaces was measured at a width of 15 mm under the condition of a crosshead speed of 200 mm / min.

[curl]
The film roll was folded in two so that the sealing surfaces face each other and one film was 5 cm long, and supplied to an automatic bag-making machine (PP5500 type manufactured by Kyoei Printing Machinery Co., Ltd.). Then, sealing and bag making were performed at a temperature setting of 300 ° C. with a fusing seal blade (blade edge angle of 60 degrees) and a bag making speed of 100 bags / min. The resulting bag was placed horizontally with one film side down, and the raised height of the film was measured with a gauge.
The case where the height was less than 3 mm was evaluated as ○, the case where 3 to 6 mm was exceeded, and the case where the height exceeded 6 m was evaluated as ×.

[Average particle size]
The volume average particle size was determined using a laser diffraction particle size distribution analyzer (Nikkiso Microtrack HRAmode 19320-X100 (Leeds & Northrup)).

[Surface resistivity (logΩ)]
A polyolefin-based resin laminated film was prepared in accordance with (2004 version) JISK-69115.13 resistivity for 16 hours under an environment of 23 ° C. and 50% relative humidity, and then the surface resistivity of the outer layer surface was measured.

[Sweeper roll trace]
The film surface was observed with the naked eye, and it was confirmed whether or not there was a trace of a sweeper roll (a roll for peeling the film from the cooling roll).

(Polymer used)
Polymers used in Examples and Comparative Examples are shown in F.
1) Propylene random copolymer (A): propylene random copolymer containing ethylene content 4% by mass, 11-butene content 4% by mass, melt flow rate 7.0 g / 1 min, melting point 130 ° C. .
2) Ethylene / α-olefin copolymer (B): containing 28% by mass of hexene-1 as a comonomer, a melt flow rate of 3 g / 10 min, and a density of 0.8909 / cm 3.
3) Slip agent master batch: 50000 ppm of enoleic acid amide was added to a propylene random copolymer containing 6% by mass of ethylene.
4) Antiblocking agent master batch: 80000 ppm of spherical silica having an average particle size of 4 μm was added to a propylene random copolymer containing an ethylene content of 6% by mass.
5) Propylene block copolymer (C): ethylene content is 13% by mass, the ratio of xylene soluble part at 20 ° C. is 25%, menoleto flow rate is 4 g / 10 min, and melting point is 163 ° C.
6) Propylene-based block copolymer (D): ethylene content is 7% by mass, the ratio of the xylene soluble part at 20 ° C. is 11%, the melt flow rate is 4 g / 10 min, and the melting point is 163 ° C.
7) Antistatic agent master batch: Propylene-ethylene random copolymer having an ethylene content of 6% by mass and a melt flow rate of 8 g / 10 min, an antistatic agent having a glycerin fatty acid ester / sodium alkyl sulfonate = 70/30 wt% Contains 15% of the agent.

(Example 1)
As shown in Table 1, the polymer and additives are blended, extruded by a three-layer T-die coextrusion cast molding machine, cooled and solidified so that the sealing surface is in contact with the cooling roll, and the total film thickness becomes 30 μm. Thus, a three-layer film was obtained. The layer thickness ratio of the film was set to inner layer / intermediate layer / outer layer 215/65/20. The die outlet resin temperature was 250 ° C. for the seal layer and the printing layer, 260 ° C. for the intermediate layer, and the temperature of the cooling roll was 25 ° C. Further, the corona treatment was performed on the outer layer surface so that the surface tension was 40 mN / m.

(Comparative Example 1)
A multilayer film was produced in the same manner as in Example 1 except that the printing surface was cooled and solidified so as to be in contact with the cooling roll.

(Comparative Example 2)
A multilayer film was produced in the same manner as in Comparative Example 1 except that the thickness ratio of the seal genus was changed to 3%.

(Comparative Example 3)
A multilayer film was produced in the same manner as in Comparative Example 1 except that the temperature of the cooling roll was 60 ° C.

(Comparative Example 4)
A multilayer film was produced in the same manner as in Comparative Example 1 except that the raw material formulation of the mat layer was changed as described in Table 1.

  The results are shown in Table 1.

  The polyolefin-based resin laminated film of the present invention is excellent in matte feeling, fusing seal strength, and has little curling at the time of bag making by fusing seal, so it can be used in a wide range of packaging fields for food and other articles such as bread and confectionery bread. It is possible that the industry can contribute.

Claims (5)

A method for producing a laminated film composed of at least two layers of a polyolefin resin, ie, a seal layer and a printed layer, wherein each of the layers has the following characteristics: A method for producing a polyolefin-based laminated film, wherein the surface on the seal layer side is in contact with a cooling roll when solidifying.
(1) Seal layer A resin composition comprising 50 to 80% by mass of the propylene random copolymer (A) and 20 to 50% by mass of an ethylene-α / olefin copolymer bag (B) having a melting point of 100 ° C. or less. .
(2) Printing layer It consists of a resin composition containing 95% by mass or more of a propylene-based block copolymer (C) having a melting point of 140 ° C. or higher.   The method for producing a polyolefin resin laminated film according to claim 1, wherein 3000 to 8000 ppm of an antistatic agent containing at least an alkyl sulfonate is added to the printed layer. Manufacturing method.   The method for producing a polyolefin-based resin laminated film according to claim 1 or 2, wherein a propylene-based block copolymer having a xylene-soluble fraction at 20 ° C of 6 to 30% between the seal layer and the printed layer. A method for producing a polyolefin-based resin laminated film, comprising an intermediate layer mainly composed of a coalescence (D).   The method for producing a polyolefin-based resin laminated film according to any one of claims 1 to 3, wherein a thickness ratio of the sealing layer is 10 to 30% of the whole. Method. A method for producing a laminated film comprising at least two layers of a polyolefin-based resin of a seal layer and a print layer, wherein each of the layers has the following characteristics, and the thickness ratio of the seal layer is 10% or more, and the following measurement The polyolefin resin laminated film characterized by having a height of less than 3 mm.
(1) Seal layer A resin composition comprising 50 to 80% by mass of the propylene random copolymer (A) and 20 to 50% by mass of an ethylene-α / olefin copolymer bag (B) having a melting point of 100 ° C. or less. .
(2) Printing layer It consists of a resin composition containing 95% by mass or more of a propylene-based block copolymer (C) having a melting point of 140 ° C. or higher.
(Measuring method)
The film was folded in two so that the sealing surfaces face each other and one film was 5 cm long, and supplied to an automatic bag making machine (PP5500 type manufactured by Kyoei Printing Machinery Co., Ltd.). And the temperature of the fusing seal blade (blade edge angle 60 degrees) is set at 300 ° C., the bag is made at a bag making speed of 100 bags / minute, and the bag is obtained by placing it horizontally with one side of the film on the bottom. The raised height was measured with a gauge.