JPH02141238A - Co-extruded laminated film - Google Patents

Abstract

PURPOSE:To improve low-temperature shock resistance, tear resistance and fusion sealing properties while enhancing workability by using a specific propylene group copolymer and specific straight-chain low-density polyethylene and co-extruding the copolymer and polyethylene by constitution within a fixed range. CONSTITUTION:A layer in which a 5-100pts.wt. crystalline propylene group random copolymer having a crystalline melting point of 150 deg.C or less is mixed with 100pts.wt. straight chain-shaped low-density polyethylene having density of 0.925 or less is used as an A layer, a layer composed of a crystalline propylene group polymer or copolymer is employed as a B layer, and a layer consisting of the crystalline propylene group random copolymer is used as a C layer. A laminated film in which the A layer is employed as a core layer and the B and C layers are laminated onto both surfaces of the core layer is manufactured. The laminated film is produced through a co-extrusion laminating method, in which these layers are melt-extruded by using a plurality of extruders, laminated under the state of melting and cooled by a water tank, a cooling roll, etc., at that time.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to coextruded laminated films. More specifically, the present invention relates to a coextruded laminated film having excellent low-temperature impact resistance, tear resistance, and fusing seal strength.

(Prior Art) Polypropylene films are widely used mainly for food packaging, taking advantage of their characteristics of high rigidity, good transparency, and heat sealability.

However, it has disadvantages such as poor low-temperature impact resistance, which limits its use in applications requiring cold resistance and low-temperature strength, and poor tear strength, which makes it unusable for packaging heavy items.

In addition, weld-sealed bags often used for textile packaging, etc.
Cut at the same time as heat sealing using a hot wire such as nichrome wire.
In the case of bags made by Ii (cut) method, the seal part is very fragile and easily tears, so there is a drawback that there are many troubles of bag breakage.

On the other hand, polyethylene film has excellent low-temperature strength and tear strength, but its transparency is poor, making it difficult to identify the contents.
It was not suitable for transparent packaging applications that require decorative properties. In addition to conventional high-density polyethylene and low-density polyethylene, in recent years, a new type of linear low-density polyethylene has been developed, which has excellent impact resistance and improved transparency compared to conventional polyethylene. The applications are being expanded by taking advantage of the characteristics such as:

However, its transparency is still inferior to that of polypropylene-based films, and if transparency is improved by polymer modification such as changing the copolymerization ratio or molding method, blocking resistance and slipping resistance will decrease. This results in a disadvantage that not only the processability and workability of printing, bag making, etc. are reduced, but also the bag opening property is poor and filling of the contents is also hindered.

As described above, all of the conventional films have advantages and disadvantages, and this has been a major constraint on the development of their applications.

[Problem to be solved by the invention]

The purpose of the present invention is to solve the drawbacks of the conventional film,
An object of the present invention is to provide a transparent packaging film that has excellent low-temperature impact resistance, tear resistance, and melt-cut sealability, and has good processability and workability.

[Means to solve the problem]

The present inventors conducted extensive research to solve the above problem, and found that by coextruding a specific propylene-based copolymer and a specific linear low-density polyethylene in a certain range of configurations, The present invention was achieved by discovering that a film with extremely excellent shelf life can be obtained.

The present invention uses a coextrusion method to coat (B) and (C) on both sides of AH.
) layer is laminated, the (A> layer is a linear low-density polyester film with a density of 0.925 or less).
5 to 100 ff of crystalline propylene-based random copolymer with a crystal melting point of 150°C or less per 100 ml of tyrene
(B) layer is a layer consisting of a crystalline propylene-based polymer or copolymer; (C) layer is a crystalline propylene-based random copolymer having a crystalline melting point of 150°C or less; It is a coextruded laminated film formed as a layer consisting of coalescence.

The present invention will be explained in detail below.

In the present invention, the linear low-density polyethylene used in the <A) layer is usually produced by combining the main component ethylene with a carbon number of 4 or more under relatively low pressure using a catalyst that combines a transition metal compound and an organometallic compound. It is a substantially linear polyethylene obtained by copolymerizing α-olefins of It is known that it is different from low-density polyethylene, which has branching, and that its molecular structure, melting characteristics, crystallization characteristics, solid state properties, and other performances are also completely different.

This linear low-density polyethylene generally has 9% ethylene.
7 to 80% by weight, 3 to 2 α-olefins having 4 or more carbon atoms
It is a copolymer consisting of 0% by weight, and among these, in the present invention, its density must be 0.925 or less. If the density exceeds 0.925, it is not preferable because it not only lacks the effects of improving impact resistance, tear strength, and melt sealability, which are the objectives of the present invention, but also reduces transparency and film smoothness.

In layer (A), this linear low density polyethylene 1
00 parts by weight, 5 to 100 weight parts of a crystalline propylene random copolymer having a crystal melting point of 150°C or lower are used. It is a binary or ternary or more copolymer obtained by copolymerizing propylene and ethylene or an α-olefin having 4 or more carbon atoms using the polymerization method of Propylene random copolymer, crystalline propylene/butene
1 copolymer, crystalline ethylene propylene butene-1
Ternary copolymers and the like are generally well known, but in the present invention, their crystal melting point must be 150° C. or lower. If the crystal melting point exceeds 150°C, (B), (C
) layer is not only deteriorated, but also the effect of improving the fusing sealing properties, which is the object of the present invention, is undesirable.

The crystal melting point in the present invention means the peak temperature of an endothermic curve accompanying melting of a crystal obtained by heating a 10rrF9 sample at a rate of 10° C. per minute using a scanning differential thermometer.

In addition, when there are two or more endothermic peaks, the one with the largest peak area is defined as the main peak, and this temperature is referred to as the crystal melting point.

This occurs, for example, when random copolymers with different proportions of copolymerization components are obtained through multistage polymerization, or when two or more types are used as a mixture. In the case of crystalline ethylene/propylene block copolymer obtained by block copolymerization of ethylene and propylene in multi-stage polymerization, the main peak at around 160°C is due to propylene as the main component, and the peak is due to the ethylene component. A sub-peak occurs around 130"C, but the main peak is 15"C.
The temperature exceeds 0° C., and the transparency is significantly reduced and cannot be applied to the present invention.

The linear low-density polyethylene (hereinafter referred to as LL, DPE) and crystalline propylene random copolymer (hereinafter referred to as PP-RC) used in this <A) layer are of a limited range. It is preferable to use L-LDPE, which is made by copolymerizing 5 to 15% by weight of α-olefin having 4 to 8 carbon atoms, has a density of 0.925 or less, and has a melt flow rate (hereinafter referred to as MFR) of 1. PP-RC is an ethylene/α-olefin copolymer with a VFR of 1 to 20 and ethylene or an α-olefin with a VFR of 1 to 20. is a crystalline copolymer with MF of PP-RC.
R (PP-MFR) and L-LDPE MFR (PE-M
FR) is 0.7<PP-MFR/PE-MFR<
It is desirable to use a mixture of those within the range of 7.0 for (A) 11, and from the viewpoint of balance of transparency, interlayer adhesion, etc.
It is particularly desirable that the MFR ratio is 165 to 5.5.

Also, the amount of PP-RC mixed into L-LDPE is L-L
PP-RC should be in the range of 5 to 100 parts by weight per 100 parts by weight of DPE.

If the mixing amount is less than 5 suspended parts, the (A) layer and (B), (C
) layer is poor, and the effect of improving the melt-cut sealing property, which is the objective of the present invention, is insufficient, and if it exceeds 1001 Jii parts, the tear strength and low-temperature impact resistance of the film decrease, which is not preferable. Among these, it is particularly preferable to mix in a range of 15 to 50 parts by weight, since various properties are balanced and the features of the present invention can be maximized.

In the present invention, the use of a resin having the above-mentioned specific composition for this (A) layer is the most important factor for improving the adhesion with (B) and (C)m and for improving various properties of the laminated film.

The crystalline propylene polymer or copolymer used for the layer (B) in the present invention is propylene alone or a copolymer containing propylene as a main component with ethylene or an α-olefin having 4 or more carbon atoms, such as , crystalline polypropylene, crystalline ethylene/propylene random copolymer, crystalline propylene/butene-1 copolymer, crystalline propylene/ethylene/butene-1 terpolymer, etc. are generally well known. These can be homopolymerized or copolymerized using known stereoregular α-olefin catalysts such as Ziegler-Natsuta, by known methods such as slurry method, solution method, gas phase method, and combination methods thereof. You can get it by letting it happen.

These propylene-based polymers or copolymers are known, but in the present invention, the same or the same kind of polymer as the PP-RC used for the above (A) layer, or (A) 1
It is desirable to have a crystal melting point equal to or higher than that of the copolymer used in layer (A), and a mixture of a copolymer of the same type as layer (A) and a propylene copolymer having a crystal melting point 5°C or more higher than that of the copolymer. It is particularly desirable to use compositions.

The crystalline propylene copolymer used for the layer (C) is prepared by copolymerizing the main component propylene with ethylene or an α-olefin having 4 or more carbon atoms using a known polymerization method for crystalline polypropylene. It is a binary or ternary or higher copolymer with a crystal melting point of 150°C or less. If the crystal melting point exceeds 150 DEG C., the melting sealability will be reduced, and the transparency will be greatly reduced, such as in the case of a single-sided cooling method of the chill-cooling method, which is not preferable.

Specifically, the copolymer for the layer (C) is preferably one of the same kind and type as the PP-RC used for the (A> layer. Among these, the copolymer has a crystal melting point of 150°C or less and a buO pyrene component of 70°C.
Contains at least % by weight, has an MFR of 1 to 20, and (A)
The ratio of VFR to MFR of the PPRC used in the layer, (C
)/(A) is particularly preferably in the range of 0, 7<(C)/(A)<1.5.

In the present invention, layers (B) and (C) are laminated on both sides of layer (A).
When a material of the same kind or type as RC, particularly preferably one with the same composition, is used for the (B) and (C) layers, the adhesion between each layer is the best, and transparency and fusing sealability are also good, which is desirable. In addition, only for the (B) layer (A>, P used for the (C) layer)
Using a polymer or copolymer with a crystal melting point 5°C or more higher than that of P-RC provides excellent sealing performance using the usual Zide seal method, in which the (C) layers are stacked and heat-sealed, and the appearance of the sealed part is also improved. Good and desirable.

A composition obtained by mixing a specific L-LDPE and a specific PP-RC used in the (A) layer of the present invention, a crystalline propylene-based polymer or copolymer used in the (B) layer, and (
C) The crystalline propylene copolymer used in the film mainly contains heat stabilizers and antioxidants such as phenol and phosphorus, and fatty acid amides, which have been commonly used as additives for polyolefin films. Slip agent, silica
Anti-blocking agents such as zeolite, antistatic agents and anti-fogging agents mainly based on surfactants such as glycerides and amine derivatives, non-quality or low crystalline ethylene/α-olefin copolymers, ethylene/vinyl acetate copolymers Polymers such as polymers, ultraviolet absorbers, colorants, etc. can be optionally added as long as they do not impair the purpose of the present invention.

L-LDPE used for layer (A) of the present invention! :PPRC
The method of mixing the polymer or copolymer used in each layer and the various additives described above may be any method as long as they are uniformly dispersed and mixed. Specifically, for example, A method for uniformly dispersing the mixture by thoroughly mixing it with a ribbon blender, Henschel mixer, Banbury mixer, etc.Furthermore, the mixture is melt-kneaded using an extruder, kneading roll, etc., and then cooled and cut to form a pellet-like composition. You may also use the method of using it as a physical object.

The (A) layer of the present invention is used as a core layer, and (B) and (C) are formed on both sides of the core layer.
) The method for producing a laminated film in which layers are laminated is (B
), (C) If II are the same polymer or copolymer, use 2 to 3 extruders, and if (B) and (C) layers are different polymers or copolymers, use 3 extruders. It can be obtained by a coextrusion lamination method in which the molten material is laminated in a molten state by melt extrusion using an extruder, coextrusion multilayer die method, feed block method, etc., and then cooled in a water bath or cooling roll. . In addition, as modifications of the present invention (A), (B), (
A method of containing C) in two or more layers, for example, (B)/
(A) / (C) / (A) / (C), (8) / (A
)/(A)/(C) (the present invention naturally also includes four or more layers).

By using this coextrusion lamination method, the thickness of each layer (A), (B), and (C) can be arbitrarily selected, and the film has an ultra-thin layer with a total thickness of 30μ or less, and the minus layer is 2 to 3μ. It is also easy to obtain. In addition, strong adhesion between each layer can be obtained without using adhesives, so it is advantageous in many respects compared to other lamination methods.

By this coextrusion multilayer die method, it is difficult to obtain a film with excellent properties, which is the object of the present invention.

For example, the method of melt-extruding and laminating the same type of resin on one or both sides of the film has poor adhesive strength and
The disadvantage is that it is difficult to uniformly laminate thin layers of 0μ or less, so in the case of dry (or solvent-free) lamination, in which two or more types of films are bonded and laminated using an adhesive, the adhesive Disadvantages include high cost due to coating, drying and curing, reduced sealing strength due to the insoluble and infusible cured adhesive, and difficulty in laminating films of 10 μm or less together due to wrinkles and loosening. There are many.

In the present invention, the thickness of layer (A) is desirably adjusted to be in the range of 20 to 90% of the total thickness using this coextrusion lamination method, and particularly preferably in the range of 30 to 70%.

This coextrusion lamination method usually involves melt extrusion using two to three extruders, lamination in the molten state using a feed block or three-layer die, and then the extruded laminate is laminated using a water bath or cooling roll. The material is rapidly cooled to form a film, and it is preferable to use a chill roll in combination with an air knife or an air chamber.

As this chill roll, either a mirror finish or a matte finish (rough) finish can be used, but it is particularly desirable to use a matte finish roll with a surface temperature of 70° C. or lower for rapid cooling. In addition, the total thickness of the film is usually desirably 10 to 120μ, and 15μ
~60μ is particularly desirable.

The cooled and solidified film is wound up and sent to the next process.
For example, it is used for the intended purpose after undergoing secondary processing steps such as printing and laminating. In addition, when surface treatment is performed to improve printability and ranemite suitability, it is desirable to treat the surface of the layer (B), which has the highest crystal melting point, and the degree of treatment is such that the wettability index measured by the method of JISK-6758 is 35.
It is preferable to process it so that it becomes 6 yn/cm or more.

Note that this surface treatment method may be any method such as corona discharge treatment, plasma treatment, flame treatment, or acid treatment, but corona discharge treatment, which can process the film continuously and can be easily performed before winding during film formation, is suitable. The most desirable treatment is simple, and plasma treatment and flame treatment are also preferred. Note that during this treatment, a method of accelerating the treatment effect, such as under heating or under an atmosphere such as an inert gas, may be used.

The thus obtained coextruded W4-layer film of the present invention is extremely useful on its own, but its functionality can be further improved by laminating it with polyester, nylon, stretched polypropylene film, etc. It is also easy to do.

(Method of Measuring Properties and Criteria for Evaluation) Measurement and evaluation of properties in the present invention were performed using the following methods and criteria.

(1) Density: Measured at 23°C based on JIS K7112. (Unit: 9/cm3) (2) Melt flow rate (VFR): JISK72
10-1976, crystalline propylene polymers or copolymers were tested under test conditions 14 (230°C, 2.16 kg
) Polyethylenes were tested under test conditions 4 (190°C, 2.16
Kg).

(3) Crystal melting point (Tm): Scanning differential calorimeter (abbreviation:
A sample of 10 #j was analyzed under nitrogen atmosphere using DSC).
It is expressed as the peak temperature (unit: 2°C) of the endothermic curve accompanying the melting of the crystal obtained by increasing the temperature at a rate of 0°C/min.

(4) Wetting index: Measured by the method of JIS K6768. (Unit: dyn/cab) Haze: According to ASTM D1003,
Four sheets of film are stacked and the measured value (unit: %) is shown as the haze of the four sheets.

The smaller this value, the better the transparency.

Tear strength: Based on ASTM D1922 Elmendorf tear strength (unit: g/llil).

Fusing seal strength: Tensile breaking strength of the sealed portion of a bag side-sealed using a side-weld bag making machine that simultaneously seals and cuts the bag using hot wire (tensile speed: 300
m+/1in) was measured. (Unit: 9/15M width) (8) Dropping strength: 100 g of polypropylene pellets were filled into a 15QN x 15cI11 bag made using a side-weld bag making machine, and the bag was top-sealed using an impulse sealer. It is expressed as the number of bags that do not break when the bags are left in a constant temperature room at -10°C for 24 hours and then 10 bags are dropped from a height of 1.0 m in the same room at the same temperature. This method is useful as a measure of the practical impact resistance of the sealed portion at low temperatures, since the bag is usually torn from the sealed portion. (Unit moss/10 bags) [Examples, Comparative Examples] The present invention will be described in more detail below using Examples and Comparative Examples, but the present invention is not limited by these.

(Examples 1 to 9, Comparative Examples 1 to 5) (A> As a shoe resin, it contains an α-olefin component with 6 carbon atoms, and has a linear low density with a density of 0.920 and an MFR of 5.0. A predetermined amount of each of the polymer or copolymer pellets shown in Table 1 was added to 100 weight portions of polyethylene pellets, and mixed in a tumbler for 10 minutes to obtain a pellet-shaped mixed composition.

(B) As a shoe resin, the ethylene content is 4
．． 5Ifflt%, MFR=7.5, Tm-140°C crystalline ethylene/propylene random copolymer pellet 100 parts by weight M parts containing ethylene h12, 5@1%, VF
R=8. 5. Blending 50 parts by weight of crystalline ethylene/propylene random copolymer pellets with Tm=150°C,
A mixed composition was prepared in the same manner. Further, as the resin for (C) shoes, a single pellet of a crystalline ethylene/propylene random copolymer with an ethylene content of 4.5% by weight used for the layer (8) was used.

Next, (A) caliber 90#ll11 for wearing, (B)
(C) For use, a 65m diameter extruder and a three-layer T-die connected to the extruder were used to form the (A) layer into the central core layer, the (B) layer, and (C) layer into the surface layer, respectively. Melt coextrusion with a composition of (B)/(A)/(C) = 1:2:1, air chamber and matte finish metal cooling roll (diameter 25 cm, surface temperature 30°C) The wettability index of the layer (B) of the film is 40 dyn/c! After corona discharge treatment while adjusting the R, the film was wound up to obtain a three-layer coextruded laminate film having a total thickness of 30 μm.

As a general rule, the extrusion temperature for the three extruders and dies is 23°C.
Example, 7, and Example, with a constant temperature of 0°C.

Only the extruder for layer 8 (A) was changed to 240°C.

The properties of the obtained film are also listed in Table 1.

The film of Comparative Example 1 was easily peeled off at the current interface between the (A) layer and the (B) layer, but many of the films of Examples were difficult to peel off, and there were also differences in adhesiveness.

As is clear from Table 1, the resin for the central core layer of the laminated film, that is, layer (A), is a composition in which linear low-density polyethylene is mixed with a specific crystalline propylene random copolymer in a specific range. When using (actual R example 1~
In 9), the quality of the film is excellent, and in the other cases (Comparative Examples 1 to 5), some of the properties are poor and unfavorable.

It can also be inferred that the propylene-based polymer or copolymer used for layer (A) is preferably one having an MFR ratio with respect to the main linear low-density polyethylene within a certain range.

(Examples 10 to 13, Comparative Examples 6 to 8) (A) Resin for shoes containing an α-olefin component having 8 carbon atoms, density 0.918, Tm=115°C, ME
100 parts by weight of linear low density polyethylene with R=2.0 contains 94% by weight of propylene component, MFR=5.0
, 25 layers of crystalline ethylene-propylene-butene-1 terpolymer having a Tm of 138° C. were blended to form a pellet-shaped mixed composition. In addition, a three-layer coextruded film was prepared in the same manner as in Example 1 using the crystalline propylene polymers or copolymers shown in Table 2 as resins (B) and (C) Iffl. 5. The extrusion temperature was constant at 240°C, the composition ratio was (B)/(A)/(C) = 1:3:1, and the total thickness was 30μ.

The properties of the obtained film are also listed in Table 2.

As is clear from Table 2, when both layers (B) and (C) are made of a crystalline propylene polymer or copolymer with a crystal melting point exceeding 150°C, tear strength, drop strength, etc. Although this is undesirable as it tends to significantly lower the transparency of the film and deteriorate the transparency of the film, at least the layer (C) has a crystal melting point of 1.
It can be seen that when a crystalline propylene copolymer having a temperature of 50° C. or lower is used, the shelf life is greatly improved and significant effects can be obtained. It is also seen that when the copolymers of layers (B), (C), and layer (A) are of the same type, a film with extremely good durability, especially strength and transparency, can be obtained.

(Examples 14 to 17, Comparative Examples 9 to 12.) (A) Polyethylene resin 100 shown in Table 3 as resin for forehead
The weight part contains the crystalline ethylene-propylene-butene 1 terpolymer used in the (Δ) layer of Example 10 (abbreviations in Table 2:
EPBT-5> was blended in an amount of 15 parts by weight to form a pellet-shaped mixed composition.

In addition, for the (B) forehead resin, ethylene was added to 100 weight a parts of the same resin as the crystalline ethylene-propylene-butene-1 terpolymer (EPBT-5) used for the formulation of the (△) layer. Content: 3.0wt 61%, Tm=147℃, MF
A pellet-shaped mixed composition was used by mixing crystalline ethylene-propylene Lander 11 copolymer 301 hanging parts with R=6.0. Further, as the resin for the forehead (C), crystalline ethylene-propylene-butene-1 ternary copolymer (EPBT-5) pellets, which were also used for the layer (B), were used alone.

Next, using a coextrusion device consisting of the same king-sized extruder and three-layer T-die as in Example 1, resin was charged into the extruder for each frame in the same manner as in Example 1, and (A) The layers (B) and (C) are combined into a central core layer and surface layers (B) and (C), respectively, and are melt-coextruded, rapidly cooled with a cooling roll at 20°C to form a film, and then immediately formed into a film (B). ) A three-layer coextruded laminated film was prepared by applying a corona discharge treatment to the layer surface and then winding it up. In addition, the extrusion temperature was set at 230° C. for each layer.

The properties of the obtained film are also listed in Table 3.

As is clear from Table 3, (A) Fi has a density of 0.92.
When linear low-density polyethylene having a molecular weight of 5 or less is used, all opening properties are excellent, but in other cases, either of the properties is significantly inferior and becomes a problem in practice.

(Comparative Example 13) The crystalline ethylene/propylene random used for (B) fN in Example 1 was produced using the factory coextrusion device consisting of the three extruders and three-layer T-die used in Example 1. The copolymer pellets were put into three extruders, and three layers of the same resin were coextruded under the same conditions as in Example 1 to form a film with a total thickness of 30 μm. The obtained film has a good haze of 6.9% and a seal strength of 1.6 kg/15 m, but a tear strength of 11 g/15 m.
ail, and all 10 bags were broken in terms of drop strength.
It could not be put to practical use at all at a low temperature of -10°C.

(Comparative Example, 14) Instead of the crystalline ethylene-propylene random copolymer of Comparative Example 13, the linear low-density polyethylene used for layer (A) of Example 1 was similarly introduced into three extrusion machines. However, a film was prepared under the same conditions as Comparative Example 13, but the film lacked rigidity and had a strong tendency to block, causing wrinkles and curls during winding. I couldn't get it. Also, haze is 15.5
%, which was an insufficient level.

〔Effect of the invention〕

The coextruded laminated film of the present invention has various excellent properties such as not only the film's WJ impact resistance and tear resistance, but also excellent fusing seal strength and good transparency. It can be used for packaging large or heavy items, which was difficult to do with conventional polypropylene films, and can be used alone or as a laminate in a variety of forms.

Claims (1)

[Claims] 1. A composite film in which layers (B) and (C) are laminated on both sides of layer A by coextrusion, wherein layer (A) has a density of 0.925 or less. A layer in which 5 to 100 parts by weight of a crystalline propylene-based random copolymer having a crystal melting point of 150°C or less is mixed with 100 parts by weight of linear low-density polyethylene. Layer (C) is a coextruded laminate film made of a crystalline propylene random copolymer having a crystalline melting point of 150° C. or less. 2. Laminated in the order of (B) / (A) / (C), the thickness of the (A) layer is 20 to 90% of the total thickness of the composite film,
2. The coextruded laminate film according to claim 1, wherein the (B) layer surface is surface-treated to have a wetting index of 35 dyn/cm or more. 3. The linear low density polyethylene used for layer (A) contains 5 to 15% by weight of α-olefin having 4 to 8 carbon atoms, has a density of 0.925 or less, and has a melt flow rate (MFR) of 1.5 to 1.5. 25 ethylene/α-olefin copolymer, the crystalline propylene random copolymer contains 70% by weight or more of a propylene component, and has a melt flow rate (
MFR) is a crystalline copolymer of propylene and ethylene or an α-olefin having 4 to 10 carbon atoms, and has a melt flow rate (PP-MFR) of a crystalline propylene random copolymer of 1 to 20. Claim 1, wherein a mixture of linear low density polyethylenes having a melt flow rate (PE-MFR) ratio of 0.7<PP-MFR/PE-MFR<7.0 is used. coextruded laminated film. 4. The crystalline propylene copolymer used for layer (C) is
Crystal melting point is below 150℃, melt flow rate (MFR)
) is 1 to 20, the ratio of melt flow rate (MFR) to the crystalline propylene random copolymer used in the (A) layer, containing 70% by weight or more of a propylene component,
4. The coextruded laminate film according to claim 3, wherein (C)/(A) is in the range of 0.7<(C)/(A)<1.5. 5. The coextruded laminate film according to claim 1, wherein the same type of copolymer as the crystalline propylene random copolymer used in layer (A) is also used in layers (B) and (C). 6. The coextruded laminate film according to claim 1, wherein the polymer or copolymer used in layer (B) has a crystal melting point higher than that of the copolymer in layer (C) by 5° C. or more. 7. Claim 1 produced by T-die chill roll cooling method.
The coextruded laminated film described.