JP6838440B2 - Propylene resin composition for multilayer stretched film - Google Patents

Description

The present invention contains a specific low calorific value propylene resin and a modified propylene resin, and has excellent adhesion between a base film composed of a polypropylene layer and a barrier layer composed of a polyamide layer, an ethylene vinyl alcohol layer, or a polyester layer. The present invention relates to a polypropylene resin composition for a multilayer stretched film, and a multilayer stretched film and a package having the propylene resin composition for a multilayer stretched film as an adhesive layer.

A laminated film of a polyolefin layer and a resin layer having a gas barrier property such as polyamide, ethylene vinyl alcohol, and polyester is effective for extending the shell life of the contents as a packaging material for foods and the like.

In recent years, in consideration of the environment, the weight and thickness of packaging materials have been reduced, but there is a problem that the strength of packaging materials is reduced due to the thinning. As a method for improving the decrease in strength due to thinning, a technique for maintaining strength by stretching has begun to spread. However, in general, when the laminated film obtained by coextrusion molding is thinned by stretching, the adhesive layer is also thinned at the same time, so that there is a problem that the adhesive strength between the base material layer and the barrier layer is lowered. Recently, there have been cases where polypropylene, which has high heat resistance and rigidity among polyolefins, is applied to the base material layer, but adhesive resins that can maintain high adhesive strength between the base material layer and the barrier layer even after stretching have been used. The current situation is that it has not been found.

Patent Document 1 discloses a polypropylene layer and a propylene-based resin composition for an adhesive layer of an ethylene vinyl alcohol layer or a polyamide layer. The resin composition of Patent Document 1 contains block polypropylene having a phase-separated structure as a main component, and further uses an ethylene / α-olefin copolymer that is phase-separated from polypropylene, so that it has excellent impact resistance at low temperatures. It is a thing. However, since this resin composition has a phase-separated structure, the formed resin layer becomes opaque. In packaging film applications such as foods, an opaque resin composition is not preferable because a display effect such as making the contents look beautiful and delicious is required. Further, although Patent Document 1 describes that it can be applied to a stretched film, there is no description about the adhesive strength after stretching, and it is unclear whether or not the adhesive strength is exhibited after stretching.

Patent Document 2 discloses an adhesive resin composition for stretching with a polar polymer layer. The resin composition of Patent Document 2 is an ethylene / α-olefin copolymer that uses block polypropylene that has a low comonomer content in the polymerized rubber component of block polypropylene and does not have a clear phase-separated structure, and that is phase-separated from polypropylene. It has excellent transparency because it does not use. However, in order to develop high adhesive strength, it is necessary to add a specific amount of the phase separation component (for example, Patent Document 3), and the resin composition of Patent Document 2 which does not contain the phase separation component has room for improvement in adhesive strength. There is.

Japanese Unexamined Patent Publication No. 4-363338 Japanese Unexamined Patent Publication No. 2004-25460 Japanese Unexamined Patent Publication No. 2-245042

The present invention provides a propylene-based resin composition for a multilayer stretched film that is transparent and exhibits high adhesive strength even after stretching, and a multilayer stretched film and a package using the propylene-based resin composition for a multilayer stretched film. Is the subject.

The present inventor has diligently studied to solve the above problems, and based on polypropylene having a high melting point that develops strength, a polyamide, ethylene vinyl alcohol, polyester, etc., together with a specific low melting calorie propylene resin that exhibits stretchability, etc. It was found that a resin composition that is transparent and has excellent adhesive strength even after stretching can be obtained by blending a modified propylene resin for adhering to the polar resin of No. 1 and further adding an ethylene-based elastomer that improves the adhesive strength. ..

That is, the gist of the present invention is as follows.

[1] A modified propylene-based resin (A) satisfying the following conditions (A-i) to (A-ii) and a low-calorie propylene-based resin (B) satisfying the following conditions (B-i) to (B-iv). ) And a propylene-based resin composition for a multilayer stretched film.
(Ai) Graft the propylene resin with at least one compound selected from the group consisting of unsaturated carboxylic acids, unsaturated carboxylic acid derivatives, unsaturated silane compounds, and unsaturated epoxy compounds in the presence of a solvent. It is a modified modified polypropylene.
(A-ii) The amount of graft is in the range of 0.01 to 10% by mass.
(Bi) The amount of heat of fusion is in the range of 0 to 50 mJ / mg.
(B-ii) The melt flow rate (MFR: 230 ° C., 2.16 kg) is in the range of 0.5 to 75 g / 10 minutes.
(B-iii) A propylene-based copolymer having a propylene unit content in the range of 65 to 90% by mass and a comonomer unit content in the range of 10 to 35% by mass.
(B-iv) At least one comonomer selected from the group consisting of ethylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-heptene, 1-hexene, 1-octene and 1-nonene. Is.

[2] The modified propylene-based resin (A) is obtained by modifying a propylene-based resin of any one of a propylene homopolymer, a propylene / ethylene copolymer, and a blend thereof with maleic acid or an anhydride thereof. The multilayer stretched film according to [1], wherein the melt flow rate (MFR: 180 ° C., 2.16 kg, orifice diameter 1 mm) is 1 to 1000 g / 10 minutes and the density is 0.86 to 0.93 g / cm ^3. Propylene resin composition.

[3] The propylene resin composition for a multilayer stretched film according to [1] or [2], wherein the comonomer of the low calorific value propylene resin (B) is ethylene and / or 1-butene.

[4] The propylene-based resin composition for a multilayer stretched film according to any one of [1] to [3], further comprising a propylene-based resin (C) satisfying the following conditions (C-i) to (C-ii). (Ci) The amount of heat of fusion is in the range of more than 50 mJ / mg and 150 mJ / mg or less.
(C-ii) The melt flow rate (MFR: 230 ° C., 2.16 kg) is in the range of 0.5 to 20 g / 10 minutes.

[5] The propylene-based resin (C) is any of a homopolymer of propylene and a copolymer of propylene and ethylene and / or 1-butene, and the content of the propylene unit is 90% by mass or more. The propylene-based resin composition for a multilayer stretched film according to [4].

[6] The propylene-based resin composition (D-) for a multilayer stretched film according to [4] or [5], which further contains an ethylene-based elastomer (D) satisfying the following conditions (D-i) to (D-iii). i) The density is in the range of ^{0.850 to 0.910 g / cm 3.}
(D-ii) The melting peak temperature is not observed or is below 100 ° C.
(D-iii) The melt flow rate (MFR: 190 ° C., 2.16 kg) is in the range of 0.1 to 75 g / 10 minutes.

[7] The ethylene-based elastomer (D) is an ethylene-propylene copolymer rubber having a propylene unit content of 15 to 65% by mass, or a non-conjugated diene unit having a propylene unit content of 15 to 65% by mass. The propylene-based resin composition for a multilayer stretched film according to [6], which is an ethylene / propylene / non-conjugated diene copolymer rubber having a content of 1 to 25% by mass.

[8] Modified propylene resin (A) in an amount of 1 to 15% by mass, low calorific value propylene resin (B) in an amount of 10 to 50% by mass, propylene resin (C) in an amount of 20 to 84% by mass, an ethylene elastomer ( The propylene-based resin composition for a multilayer stretched film according to [6] or [7], which contains 5 to 15% by mass of D).

[9] An adhesive layer made of the propylene-based resin composition for a multilayer stretched film according to any one of [1] to [8], a polypropylene layer laminated on one surface of the adhesive layer, and the other surface. A multilayer stretched film having a laminated polyamide layer, an ethylene vinyl alcohol layer, or a polyester layer.

[10] A packaging body using the multilayer stretched film according to [9].

The propylene-based resin composition for a multilayer stretched film of the present invention is transparent and exhibits high adhesive strength even after stretching. Therefore, the laminate obtained by using the propylene resin composition for a multilayer stretched film of the present invention as an adhesive resin between a polypropylene layer as a base material layer, a polyamide layer as a barrier layer, an ethylene vinyl alcohol layer, or a polyester layer. By stretching the film, it is possible to provide a multilayer stretched film and a package having high interlayer adhesion strength after reducing the wall thickness and weight.

The present invention will be described in detail below, but the following description is an example of an embodiment of the present invention, and the present invention is not limited to the following description as long as the gist of the present invention is not exceeded. It can be arbitrarily modified and carried out without departing from the gist of the invention.
In addition, in this invention, when a numerical value or a physical property value is put before and after using "~", it is used as including the value before and after that.

In the present invention, the melt flow rate (MFR) and density of the resin are values measured as follows.

<MFR>
The MFR of the propylene-based resin before graft modification of the modified propylene-based resin (A), the low-calorie propylene-based resin (B), and the propylene-based resin (C) has a temperature of 230 ° C. in accordance with ISO 1133: 1997 Connections M. , Load 2.16 kg, measured under the condition of 10 minutes. The MFR of low-density polyethylene of ethylene-based elastomer (D) is measured at a temperature of 190 ° C., a load of 2.16 kg, and 10 minutes in accordance with ISO 1133: 1997 Conditions M. The MFR of the modified propylene resin (A) is measured using an orifice diameter of 1 mm under the conditions of a temperature of 180 ° C., a load of 2.16 kg, and 10 minutes.

<Density>
It is measured by the underwater substitution method according to JIS K7112.

Further, the heat of fusion of the low calorific value propylene resin (B) and the propylene resin (C) and the peak melting temperature of the ethylene elastomer (D) can be determined by the following DSC measurement.

<DSC measurement>
Using a differential operating calorimeter (DSC), once raise the temperature to 200 ° C to erase the heat history, then lower the temperature to -10 ° C at a temperature lowering rate of 10 ° C / min, and then raise the temperature again to 10 ° C / min. The temperature at the top of the endothermic peak when the temperature was raised and measured was defined as the melting peak temperature. At this time, the melting peak temperature was not measured for those without an endothermic peak top. The unit is ° C.
For the amount of heat of fusion, the integrated value of the endothermic peaks from 20 ° C. to 180 ° C. was determined. The unit is mJ / mg.

[Propylene-based resin composition for multilayer stretched film]
The propylene-based resin composition for a multilayer stretched film of the present invention (hereinafter, may be referred to as “resin composition of the present invention”) is a specific modified propylene-based resin (A) and a specific low-calorie propene-based resin. (B) is essential, and preferably further contains a propylene-based resin (C) having a larger heat of fusion than the low heat-melting propylene-based resin (B) and an ethylene-based elastomer (D).

[mechanism]
The modified propylene resin (A) is an essential component for adhesion to barrier layers such as a polyamide layer, an ethylene vinyl alcohol layer, and a polyester layer, and is a polar group of the modified propylene resin (A) and a polar group of the above-mentioned barrier layer resin. Adhesiveness is developed by interaction with.

The low heat of fusion propylene resin (B) has a heat of fusion in the range of 0 to 50 mJ / mg, and is involved in maintaining the adhesive strength of the propylene resin composition for a multilayer stretched film after stretching. The heat of fusion of a general propylene resin is about 51 to 150 mJ / mg, and the low heat of fusion propylene resin (B) is characterized by lower crystallinity and more amorphous components than the general propylene resin. Therefore, the large amount of the amorphous component is effective in maintaining the adhesive strength after stretching.
That is, before stretching, the interaction between the polar group of the barrier resin constituting the barrier layer and the polar group of the modified propylene resin (A) in the resin composition constituting the adhesive layer is the interaction between the modified propylene resin (A) and the barrier. It is presumed that a pseudo-graft copolymer of the resin is generated, thereby exhibiting adhesive strength. However, by stretching, the pseudo-graft copolymer is also stretched and the interaction points are separated. , It is estimated that the adhesive strength decreases.
In the propylene-based resin composition for a multilayer stretched film of the present invention, the low-calorie propylene-based resin (B) has a large amount of amorphous components, which makes it difficult for the above-mentioned pseudo graft copolymer to be stretched. Alternatively, it is presumed that the adhesive strength after stretching is maintained by the action of relaxing even if it is stretched.
Since the above mechanism is manifested by the low melting calorific value resin being compatible with the modified resin that contributes to adhesion, when the modified resin is a propylene-based resin, the low melting calorific value resin must also be a propylene-based resin. Is.

The propylene-based resin (C) having a heat of fusion of more than 50 mJ / mg and 150 mJ / mg or less is a component for imparting rigidity to the adhesive layer. Since stretching is performed to compensate for the decrease in strength due to thinning, it is preferable that the film rigidity after stretching is high. Since the propylene-based resin composition for a multilayer stretched film of the present invention is a flexible component other than the propylene-based resin (C), it is preferable to contain the propylene-based resin (C) in order to maintain the rigidity of the entire film.

The ethylene-based elastomer (D) is a component for alleviating the strain applied to the adhesive layer during stretching and maintaining the adhesive strength after stretching. By using an ethylene-based elastomer (D) that is incompatible with the main component propylene-based resin, a phase-separated structure such as a sea-island structure is obtained, and the strain received by the sea phase composed of the propylene-based resin is applied to the ethylene-based elastomer (D). It is presumed that the adhesive strength can be maintained by relaxing with the island phase composed of D).

The low calorific value propylene resin (B) is a compatible easing component, and the ethylene elastomer (D) is an incompatible easing component. It is necessary to reduce the strain received by stretching from both the sea phase and the island phase in order to maintain the adhesive strength.

[Modified propylene resin (A)]
The modified propylene-based resin (A) satisfies the following conditions (A-i) to (A-ii), and one of them may be used alone. Two or more kinds having different types, graft amounts, other physical properties, etc. may be mixed and used.
(Ai) A propylene-based resin (hereinafter, may be referred to as a “raw material propylene-based resin”) is an unsaturated carboxylic acid, an unsaturated carboxylic acid derivative, an unsaturated silane compound, and an unsaturated carboxylic acid in the presence of a solvent. A modified polypropylene graft-modified with at least one compound selected from the group consisting of epoxy compounds.
(A-ii) The amount of graft is in the range of 0.01 to 10% by mass.

In the present invention, unsaturated carboxylic acids, unsaturated carboxylic acid derivatives, unsaturated silane compounds, and unsaturated epoxy compounds may be collectively referred to as "denaturing agents".

<Raw material propylene resin>
The propylene-based resin used as the raw material of the modified propylene-based resin (A) is not limited as long as it is a resin containing a propylene monomer unit as a main component, but usually, the propylene unit is 50% by mass or more, preferably 70% by mass or more. , More preferably 80% by mass or more of the polymer.

The propylene-based resin used as the raw material of the modified propylene-based resin (A) is not particularly limited as long as it corresponds to the above, and specifically, a propylene homopolymer, a propylene / ethylene copolymer, and a propylene / 1-. Butene copolymer, propylene / ethylene / 1-butene copolymer, propylene / 4-methyl-1-pentene copolymer, copolymer of propylene and other α-olefins, propylene and other vinyl monomers Examples thereof include copolymers. Here, other α-olefins, that is, α-olefins other than propylene are not limited, but usually, hydrocarbons having a double bond having 4 to 20 carbon atoms, preferably 4 to 10 carbon atoms can be mentioned. Further, "other vinyl monomers" are also not limited, and examples thereof include vinyl acetate, vinyl alcohol, (meth) acrylic acid, (meth) acrylic acid alkyl ester, styrene, and styrene derivatives.

Further, as the raw material propylene resin, two or more of the above resins may be used in combination. The above-mentioned copolymers may be block copolymers, graft copolymers, random copolymers, or the like.

Among these, as the raw material propylene-based resin, a propylene homopolymer, a propylene / ethylene copolymer, and a blend thereof are preferable, and a propylene homopolymer is more preferable.

The three-dimensional regularity of the raw material propylene-based resin is not limited, and the propylene chain may be any of isotactic, syndiotactic, atactic, stereoblock, etc., but the propylene chain is preferably isotactic, in particular. Isotactic homopolypropylene is preferred. Further, as the catalyst used for the polymerization, a known catalyst can be appropriately adopted.

In the present invention, the melt flow rate (MFR: 230 ° C., 2.16 kg) of the propylene-based resin used as the raw material of the modified propylene-based resin (A) is not limited, but is usually 0.01 to 1000 g / 10 minutes, preferably 0. .1 to 100 g / 10 minutes, more preferably 1 to 50 g / 10 minutes. When the MFR is smaller than the lower limit, the fluidity of the propylene-based resin composition for a multilayer stretched film of the present invention tends to be inferior, and the graft ratio of the modified propylene-based resin (A) also tends to decrease. .. Further, when the MFR is larger than the upper limit value, the physical strength of the propylene-based resin composition for a multilayer stretched film of the present invention tends to decrease.

<Denaturant>
As the modifier for modifying the raw material propylene resin, at least one compound selected from the group consisting of unsaturated carboxylic acids, unsaturated carboxylic acid derivatives, unsaturated silane compounds, and unsaturated epoxy compounds is used.

Unsaturated carboxylic acid as a modifier is not limited, but specifically, α, β-ethylenically unsaturated carboxylic acid is preferable, for example, acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, tetrahydrophthalic acid. Acids, itaconic acid, citraconic acid, crotonic acid, isocrotonic acid and the like can be mentioned. Examples of the unsaturated carboxylic acid derivative include acid anhydrides and carboxylic acid esters, and further, derivatives such as acid halides, amides and imides may be used. Acid anhydrides are preferred as these derivatives. Among these, maleic acid or its anhydride is particularly preferable.

The unsaturated silane compound as modifier, for example, those represented by the general formula RSiR _{'n Y 3-n.} Here, R is an ethylenically unsaturated hydrocarbon group or a hydrocarbon oxy group, for example, a vinyl group, an allyl group, an isopropenyl group, a butenyl group, a cyclohexenyl group, a γ- (meth) acryloyloxypropyl group and the like. A vinyl group or a γ- (meth) acryloyloxypropyl group is preferred. R'is an aliphatic saturated hydrocarbon group, and examples thereof include a methyl group, an ethyl group, a propyl group, a decyl group, and a phenyl group. Y represents a hydrolyzable organic group, and examples thereof include a methoxy group, an ethoxy group, a formyloxy group, an acetoxy group, a propionyloxy group, an arylamino group and the like, and a methoxy group, an ethoxy group or an acetoxy group is preferable. n represents 0, 1 or 2, preferably 0.

Among the unsaturated silane compounds, vinyl trimethoxysilane, vinyl triethoxysilane, vinyl triethoxysilane, vinyl triacetoxysilane, and γ-methacryloyloxypropyltrimethoxysilane are preferable.

The unsaturated epoxy compound as a modifier is not limited as long as it is a compound having an ethylenically unsaturated hydrocarbon group and an epoxy group, and is disclosed in, for example, glycidyl acrylate, glycidyl methacrylate, or JP-A-2-51550. Examples thereof include an acrylamide monomer having an epoxy group.

Among these modifiers, unsaturated carboxylic acids or derivatives thereof are particularly suitable. The unsaturated carboxylic acid or its derivative, the unsaturated silane compound, and the unsaturated epoxy compound as the modifier may be one kind or a combination of two or more kinds.

<Degeneration method>
The modification for obtaining the modified propylene resin (A) needs to be performed in the presence of a solvent (hereinafter, the modification method performed in the presence of a solvent may be referred to as "solution modification"). If a solution denaturing method is used as the denaturing method, it is possible to reduce the amount of unreacted denaturing agent and radical generating agent remaining in the resin. Further, by optimizing the type of solvent described later, the concentration at the time of denaturation, the reaction temperature and the reaction time, denaturation can be performed with a high amount of graft. Further, it is possible to suppress an increase (decrease in molecular weight) of the MFR of the modified propylene-based resin (A) obtained by modification with respect to the MFR of the raw material propylene-based resin. On the contrary, control for obtaining a graft having a high MFR (low molecular weight) is also facilitated.

Due to these characteristics, by adopting the modified propylene-based resin (A) obtained by the solution modification method, the propylene-based resin composition for a multilayer stretched film of the present invention has high adhesive strength with various resins. Further, the multilayer stretched film using the propylene resin composition for the multilayer stretched film of the present invention as an adhesive layer exhibits high interlayer adhesive strength.

As a specific method of solution denaturation, a method of dissolving a raw material propylene resin in an organic solvent or the like, adding a denaturing agent and a radical generator to the raw material propylene resin, and graft-copolymerizing the resin can be adopted. The raw material propylene resin does not necessarily have to be completely dissolved in the solvent, and may be in a swollen state, dispersed or suspended state in the solvent.

The organic solvent used is not particularly limited, and for example, an aromatic hydrocarbon solvent, an alkyl group-substituted aromatic hydrocarbon solvent, a halogenated hydrocarbon solvent, or an aliphatic hydrocarbon solvent can be used. Specifically, aromatic hydrocarbon solvents such as benzene, toluene and xylene, alkyl group-substituted aromatic hydrocarbon solvents; aliphatic hydrocarbon solvents such as pentane, hexane and heptane; halogenated aromatic solvents such as chlorobenzene and bromobenzene. Examples thereof include a hydrocarbon solvent, and among these, xylene, chlorobenzene and the like are preferable. The temperature at which the solution is denatured is not limited, but it can be usually 70 to 200 ° C., preferably 80 to 190 ° C. The solution denaturation can be carried out by reacting for 0.5 to 15 hours, preferably 1 to 10 hours.

The mixing ratio of the raw material propylene resin and the modifier is not limited, but the modifier is usually 0.01 to 30 parts by mass, preferably 0.05 to 10 parts by mass, more preferably with respect to 100 parts by mass of the raw propylene resin. Is preferably blended in a proportion of 0.1 to 5 parts by mass.

The radical generator is not limited, but specifically, benzoyl peroxide, dicumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di (peroxybenzoate) hexin-3, lauroyl. Peroxide, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexin-3, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexane, tert-butylperbenzoate , Tert-butylperisobutyrate, tert-butylperpivalate, organic peroxides and organic peroxides such as cumylperpivalate, or azo compounds such as azobisisobutyronitrile and dimethylazoisobutyrate. Etc. can be used.

These radical generators can be appropriately selected and used according to the type of raw material propylene resin, MFR, type of denaturant, reaction conditions, etc., and two or more of them may be used in combination. The amount of the radical generator used is not limited, but is usually 0.001 to 20 parts by mass, preferably 0.005 to 10 parts by mass, and more preferably 0.01 to 5 parts by mass with respect to 100 parts by mass of the raw material propylene resin. , Particularly preferably 0.01 to 3 parts by mass.

As the modified propylene resin (A) in the present invention, a modified propylene resin modified by a method other than solution modification may be used in combination as long as the effects of the present invention are not impaired. The method other than the solution denaturation is not limited, and the reaction can be obtained only by heat, but a melt denaturation method and the like can be mentioned.

As a melt modification method, a method in which a raw material propylene resin, a modifier, and if necessary, the above-mentioned radical generator are mixed in advance and then melt-kneaded in a kneader to react, or a polypropylene resin melted in a kneader is used. A method of adding a mixture of a radical generator and a denaturing agent from the inlet of the raw material and reacting the mixture can be used. A Henschel mixer, ribbon blender, V-type blender or the like is usually used for mixing, and a single-screw or twin-screw extruder, roll, Banbury mixer, kneader, lavender mixer or the like can be usually used for melt-kneading. ..

<Graft amount>
The graft amount (modification amount by the modifier) of the modified propylene resin (A) is 0.01% by mass or more, preferably 0.05% by mass or more, more preferably 0.1% by mass or more, while 10% by mass. % Or less, preferably 7% by mass or less, more preferably 5% by mass or less. When the amount of graft in the modified propylene resin (A) is less than the lower limit, the adhesive strength between the resin composition of the present invention and another resin tends to be insufficient. If the amount of graft exceeds the upper limit, gelation, coloring, deterioration of the resin, etc. may occur during the graft reaction, and it is practically difficult to produce the modified propylene resin (A).

Here, the amount of graft ^{can be confirmed by, for example, 1} H-NMR, infrared absorption spectrum, ICP emission spectrometry using a high-frequency plasma emission spectrometer, or the like.

When an unsaturated carboxylic acid or a derivative thereof is used as the denaturing agent, for example, absorption peculiar to the carboxylic acid or its derivative in a sample press-molded into a sheet having a thickness of about 100 μm, specifically, 1900 to 1600 cm ^-1 (1) It can be obtained by measuring the absorption of carbonyl characteristics in the C = O expansion and contraction vibration band).

When an unsaturated silane compound is used as the modifier, the amount of graft is measured by heating and burning the sample to incinerate it, melting the ash with alkali, dissolving it in pure water, and then dissolving it in a constant solution. Can be confirmed by the ICI luminescence analysis method using.

In the modification with a denaturant, 100% of the denaturant is not subjected to the reaction, and the denaturant that has not reacted with the raw material propylene resin may remain in the modified propylene resin (A). The amount of denaturation in the above means a value when measured by the above method.

<Unreacted denaturant>
Since the modified propylene resin (A) used in the present invention is produced by a solution modification method, there are few by-products such as modifiers and oligomers that are not chemically bonded to the raw material propylene resin. It exhibits high adhesive strength, emits less smoke during molding, and can reduce the environmental load. Therefore, the propylene-based resin composition for a multilayer stretched film of the present invention containing this can be suitably used as an adhesive layer in the multilayer stretched film. Furthermore, since it is possible to obtain a multilayer stretched film having a small amount of unreacted components and oligomer components, high adhesive strength, and reduced odor and coloring caused by unreacted components, it is possible to obtain an adhesive layer for packaging for medical use and foods. Can be suitably used as.
Further, since there are few unreacted components and oligomer components, the change in adhesive strength with time is small, and it can be suitably used as an adhesive layer suitable for industrial materials.

The content of the unreacted modifier in the modified propylene resin (A) is not limited, but the content measured using an infrared spectrophotometer is usually 1000 ppm by weight or less, preferably 100 ppm by weight or less, more preferably. Is preferably 10 wt ppm or less. As a method for reducing the content of the unreacted modifier of the modified propylene resin (A) to the above upper limit value or less, for example, a method of optimizing the conditions of the solution modification method or a method of purifying by washing or extraction after the graft reaction. Can be mentioned.
The lower limit of the content of the unreacted modifier is not limited, and it is desirable that the unreacted modifier is not contained (0 ppm by weight). However, in order to reduce the content to 0 ppm, it is necessary to perform an excessive reduction treatment by a method such as washing or extraction. As it occurs, it is usually 0.001 ppm by weight or more, preferably 0.01 ppm by weight or more.

<Other physical characteristics>
The melt flow rate (MFR: 180 ° C., 2.16 kg, orifice diameter 1 mm) of the modified propylene resin (A) is not limited, but the lower limit thereof is usually 1 g / 10 minutes or more, preferably 10 g / min or more, more preferably. Is 5 g / min or more, more preferably 10 g / min or more, and the upper limit thereof is usually 1000 g / 10 minutes or less, preferably 900 g / 10 minutes or less, more preferably 800 g / 10 minutes or less, still more preferably 700 g / 10. Less than a minute. If the MFR is less than the above lower limit, the dispersion in the propylene resin becomes poor, and there is a concern that the adhesive strength is lowered. If it exceeds the above upper limit, there is a concern that the mechanical strength will decrease.

The density of the modified propylene resin (A) is preferably ^{0.86 to 0.93 g / cm 3.} When the density of the modified propylene resin (A) is less than the above lower limit, the mechanical strength tends to decrease. Further, when the density of the modified propylene resin (A) exceeds the above upper limit value, the adhesiveness tends to decrease, and the transparency tends to further deteriorate.
The density of the modified propylene resin (A) is preferably 0.87 g / cm ³ or more, and preferably 0.89 g / cm ³ or less for the same reason as described above.

[Low heat of fusion propylene resin (B)]
The low calorific value propylene resin (B) satisfies the following conditions (Bi) to (B-iv), and one type may be used alone, and the type of comonomer and the content of the comonomer unit, Two or more kinds of substances having different physical properties such as heat of fusion and MFR may be mixed and used.
(Bi) The amount of heat of fusion is in the range of 0 to 50 mJ / mg.
(B-ii) The melt flow rate (MFR: 230 ° C., 2.16 kg) is in the range of 0.5 to 75 g / 10 minutes.
(B-iii) A propylene-based copolymer having a propylene unit content in the range of 65 to 90% by mass and a comonomer unit content in the range of 10 to 35% by mass.
(B-iv) At least one comonomer selected from the group consisting of ethylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-heptene, 1-hexene, 1-octene and 1-nonene. Is.

The copolymerization ratio of propylene and comonomer in the propylene-based copolymer of the low calorific value propylene resin (B) is the content of propylene unit, where the total of the content of propylene unit and the content of comonomer unit is 100% by mass. The amount is 65 to 90% by mass and the content of the comonomer unit is 10 to 35% by mass, preferably the content of the propylene unit is 65.5 to 89.5% by mass and the content of the comonomer unit is 10.5. It is ~ 34.5% by mass, more preferably the content of the propylene unit is 66 to 89% by mass, and the content of the comonomer unit is 11 to 34% by mass.
If the content of the propylene unit exceeds the above upper limit, it becomes difficult to maintain a low heat of melting, and the relaxing effect of the stretched state by stretching is weakened, which is not preferable. Further, when the content of the propylene unit is less than the above lower limit, the phase is separated from the propylene-based resin in the sea phase, and the effect of relaxing the sea phase cannot be obtained, which is not preferable.

The comonomer of the propylene-based copolymer of the low calorific value propylene-based resin (B) is ethylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-heptene, 1-hexene, 1-octene and 1 -At least one selected from the group consisting of nonene, preferably ethylene, 1-butene.

The low calorific value propylene resin (B) contains a comonomer unit other than the above comonomer within a range not impairing the object of the present invention, for example, in a range of 10% by mass or less in the low calorific value propylene resin (B). Examples of the other comonomer include "other vinyl monomers" in the raw material propylene resin of the modified propylene resin (A) described above.

Further, the low heat of fusion propylene resin (B) needs to have a heat of fusion of 50 mJ / mg or less in order to maintain the adhesive strength after stretching, and does not have a heat of fusion of more than 50 mJ / mg. The crystal component is not sufficient, and the growth inhibition or relaxation of the pseudo graft copolymer is insufficient, and the decrease in adhesive strength after stretching cannot be prevented. Low heat of melting The heat of melting of the propylene resin (B) is preferably 45 mJ / mg or less, more preferably 40 mJ / mg or less. On the other hand, the lower limit of the amount of heat of fusion is preferably 2 mJ / mg or more, more preferably 5 mJ / mg or more, from the viewpoint of maintaining mechanical strength.

Further, the melt flow rate (MFR: 230 ° C., 2.16 kg) of the low heat calorific value propylene resin (B) is 0.5 to 75 g / 10 minutes. When the MFR of the low calorific value propylene resin (B) exceeds the above upper limit, the MFR as a composition becomes high and the moldability becomes unstable, which is not preferable. On the other hand, when the MFR is less than the above lower limit, the cohesive force by itself becomes strong and the uniform mixing with other components becomes insufficient, which is not preferable. The MFR of the low calorific value propylene resin (B) is preferably 1 to 70 g / 10 minutes, more preferably 2 to 65 g / 10 minutes.

[Propene resin (C)]
The propylene-based resin (C) satisfies the following conditions (C-i) to (C-ii), and one type may be used alone, and the type of comonomer, the content of comonomer units, the amount of heat of fusion, and the like. Two or more kinds of substances having different physical properties such as MFR may be mixed and used.
(Ci) The amount of heat of fusion is in the range of more than 51 mJ / mg and 150 mJ / mg or less.
(C-ii) The melt flow rate (MFR: 230 ° C., 2.16 kg) is in the range of 0.5 to 20 g / 10 minutes.

The propylene-based resin (C) is not particularly limited in the type and composition of the copolymer as long as it satisfies the physical properties of (C-i) to (C-ii), but propylene alone is preferable. Examples thereof include polymers, propylene and ethylene, 1-butene, and other copolymers of one or more, and having a propylene unit content of 90% by mass or more.

The propylene-based resin (C) needs to have a heat of fusion in the range of more than 50 mJ / mg and 150 mJ / mg or less in order to impart rigidity to the adhesive layer. If the heat of fusion of the propylene resin (C) is 50 mJ / mg or less, sufficient rigidity cannot be imparted, and it is difficult to obtain a propylene resin having a heat of fusion of more than 150 mJ / mg in production.
The calorific value of the propylene resin (C) for melting is preferably 55 to 145 mJ / mg, more preferably 60 to 140 mJ / mg.

The melt flow rate (MFR: 230 ° C., 2.16 kg) of the propylene resin (C) is 0.5 to 20 g / 10 minutes. When the MFR of the propylene-based resin (C) exceeds the above upper limit, the MFR as a composition becomes high and the moldability becomes unstable, which is not preferable. On the other hand, when the MFR is less than the above lower limit, the cohesive force by itself becomes strong and the uniform mixing with other components becomes insufficient, which is not preferable. The MFR of the propylene resin (C) is preferably 0.7 to 19 g / 10 minutes, more preferably 1 to 18 g / 10 minutes.

[Ethylene elastomer (D)]
The ethylene-based elastomer (D) satisfies the following conditions (D-i) to (D-iii), and one type may be used alone, or two or more types having different comonomer compositions and physical characteristics are mixed. May be used.
(Di) The density is in the range of ^{0.850 to 0.910 g / cm 3.}
(D-ii) The melting peak temperature is not observed or is below 100 ° C.
(D-iii) The melt flow rate (MFR: 190 ° C., 2.16 kg) is in the range of 0.1 to 75 g / 10 minutes.

Examples of the ethylene-based elastomer (D) include ethylene / propylene copolymer rubber, ethylene / propylene / non-conjugated diene copolymer rubber, ethylene / butene-1 copolymer rubber, and ethylene / butene-1 / non-conjugated diene copolymer rubber. And so on. Here, examples of the non-conjugated diene include ethylidene norbornene, dicyclopentadiene, 1,4-hexadiene, cyclooctadiene, etc. Among them, ethylidene norbornene and dicyclopentadiene are preferable, and etylidene norbornene is particularly preferable.

When ethylene / propylene copolymer rubber is used as the ethylene-based elastomer (D), the propylene unit content is in the range of 15 to 65% by mass, and when ethylene / propylene / non-conjugated diene copolymer rubber is used. , The propylene unit content of 15 to 65% by mass and the non-conjugated diene unit content of 1 to 25% by mass are preferable from the viewpoint of rubber elasticity.

The density of the ethylene-based elastomer (D) is 0.850 to 0.910 g / cm ³ . If the density of the ethylene-based elastomer (D) ^{exceeds 0.910 g / cm 3} , it becomes rigid and the strain cannot be sufficiently relaxed. The density of the ethylene-based elastomer (D) is preferably 0.905 g / cm ³ or less, and more preferably 0.900 g / cm ³ or less. On the other hand, it is difficult to obtain an ethylene-based elastomer having ^{a density of less than 0.850 g / cm 3.}

Further, the ethylene-based elastomer (D) has a melting peak temperature of 100 ° C. or lower when it is not observed or is observed. An ethylene-based elastomer (D) having a melting peak temperature of more than 100 ° C. is not preferable because it becomes rigid and strain cannot be sufficiently relaxed. The ethylene-based elastomer (D) preferably has no melting peak temperature observed, or if it is observed, it is 95 ° C. or lower, more preferably 90 ° C. or lower, and most preferably no melting peak temperature is observed.

The melt flow rate (MFR: 190 ° C., 2.16 kg) of the ethylene-based elastomer (D) is 0.1 to 75 g / 10 minutes. When the MFR of the ethylene-based elastomer (D) exceeds the above upper limit, the MFR as a composition becomes high and the moldability becomes unstable, which is not preferable. On the other hand, when the MFR is less than the above lower limit, the cohesive force by itself becomes strong and the uniform mixing with other components becomes insufficient, which is not preferable. The MFR of the ethylene-based elastomer (D) is preferably 0.5 to 70 g / 10 minutes, more preferably 1 to 65 g / 10 minutes.

[Content of each component]
The propylene-based resin composition for a multilayer stretched film of the present invention contains a modified propylene-based resin (A) and a low calorific value propylene-based resin (B), preferably further a propylene-based resin (C) and an ethylene-based elastomer (D). In order to more reliably obtain the action and effect of the above-mentioned blending of each component, 1 to 15% by mass of the modified propylene-based resin (A) is contained in 100% by mass of the propylene-based resin composition for a multilayer stretched film. Low heat of fusion It is preferable that the propylene resin (B) is contained in an amount of 10 to 50% by mass, the propylene resin (C) is contained in an amount of 20 to 84% by mass, and the ethylene elastomer (D) is contained in an amount of 5 to 15% by mass. (A) is 2 to 14% by mass, low heat of fusion propylene resin (B) is 11 to 49% by mass, propylene resin (C) is 21 to 83% by mass, and ethylene elastomer (D) is 6 to 14% by mass. %, More preferably, the modified propylene resin (A) is 3 to 13% by mass, the low heat of fusion propylene resin (B) is 12 to 48% by mass, and the propylene resin (C) is 22 to 82% by mass. It is particularly preferable to contain 7 to 13% by mass of the ethylene-based elastomer (D).

[Other ingredients]
The propylene-based resin composition for a multilayer stretched film of the present invention includes the above-mentioned modified propylene-based resin (A), low calorific value propylene-based resin (B), and propylene-based resin (as long as the effects of the present invention are not significantly impaired. In addition to C) and the ethylene-based elastomer (D), additives, resins and the like (hereinafter, may be referred to as other components) can be blended. As for the other components, only one type may be used, or two or more types may be used in combination in any combination and ratio.

The additives that can be used in the propylene-based resin composition for a multilayer stretched film of the present invention are not limited, but specifically, heat-resistant stabilizers, weather-resistant stabilizers (antioxidants, light stabilizers, ultraviolet absorbers, etc.), Flame retardants, anti-blocking agents, slip agents, antistatic agents, fillers (inorganic and / or organic fillers, etc.), processing aids, plasticizers, crystal nucleating agents, impact modifiers, compatibilizers, neutralization of catalyst residues Agents, carbon blacks, colorants (pigments, dyes, etc.) and the like can be mentioned. When these additives are used, the content thereof is not limited, but is usually 0.01% by mass or more, preferably 0.2% by mass or more, and usually 5% by mass or less, preferably 5% by mass or less, based on the resin composition. Is preferably 2% by mass or less.

A tackifier can also be used as another component in the propylene-based resin composition for a multilayer stretched film of the present invention. Here, examples of the tackifier include amorphous resins that are solid at room temperature, and examples thereof include petroleum resins, rosin resins, terpene resins, and hydrogen additives thereof. However, if a large amount of the tackifier is contained in the resin composition, smoke may be generated during molding, or the tackifier may leak into the food or drink when used as a material for packaging oily food or drink. .. Therefore, even when a tackifier is used, it is preferably 25% by mass or less, more preferably 20% by mass or less, still more preferably 17% by mass or less, and particularly preferably less than 15% by mass in the resin composition. Most preferably, it contains substantially no tackifier. The propylene-based resin composition for a multilayer stretched film of the present invention has good adhesiveness to a base material layer and a barrier layer when used as an adhesive layer of a multilayer stretched film even when a tackifier is not used. Good adhesion to the base material layer and the barrier layer can be maintained even after stretching.

Examples of the petroleum resin include aliphatic petroleum resins, aromatic petroleum resins, copolymers thereof, and hydrogenated additives thereof. The skeleton of the petroleum resin includes C5 resin, C9 resin, C5 / C9 copolymer resin, cyclopentadiene resin, polymer of vinyl-substituted aromatic compound, copolymer of olefin / vinyl-substituted aromatic compound, cyclopentadiene-based. Examples thereof include copolymers of compound / vinyl-substituted aromatic compounds, and hydrogenated products thereof.
The rosin resin is a natural resin containing avietic acid as a main component. For example, natural rosin, polymerized rosin derived from natural rosin, and stabilized rosin obtained by disproportionating or hydrogenating natural rosin or polymerized rosin. Examples thereof include unsaturated acid-modified rosin obtained by adding unsaturated carboxylic acids to natural rosin and polymerized rosin, natural rosin ester, modified rosin ester, and polymerized rosin ester.
Examples of the terpene resin include aromatic terpene resins such as polyterpene resin and terpene phenol resin, aromatic-modified terpene resins, and hydrogenated products thereof.

The resin used as other components is not limited, but for example, polyphenylene ether resin; polycarbonate resin; polyamide resin such as nylon 66 and nylon 11, polyester resin such as polyethylene terephthalate and polybutylene terephthalate, and styrene resin such as polystyrene. , And acrylic / methacrylic resins such as polymethylmethacrylate resins.

[Manufacturing method of propylene resin composition for multilayer stretched film]
The propylene-based resin composition for a multilayer stretched film of the present invention can be obtained by mixing the above-mentioned components in a predetermined ratio.
The mixing method is not particularly limited as long as the raw material components are uniformly dispersed. That is, by mixing the above-mentioned raw material components and the like at the same time or in an arbitrary order, a composition in which each component is uniformly dispersed is obtained.
For more uniform mixing and dispersion, it is preferable to melt-mix a predetermined amount of the above-mentioned raw material components. For example, each raw material component of the resin composition of the present invention may be mixed in an arbitrary order and then heated. , All raw material components and the like may be sequentially melted and mixed, or a mixture of each raw material component and the like may be pelletized or melt-mixed at the time of molding when producing the target molded product.

In the propylene-based resin composition for a multilayer stretched film of the present invention, a predetermined amount of the above-mentioned raw material components are mixed by various known methods, for example, a tumbler blender, a V blender, a ribbon blender, a Henschel mixer, etc., and after mixing, a single shaft It can be prepared by a method of melt-kneading with an extruder, a twin-screw extruder, a Banbury mixer, a kneader or the like, and granulating or crushing. The temperature at the time of melt-kneading may be a temperature at which at least one of the raw material components is in a molten state, but a temperature at which all the components to be used are melted is usually selected, and is generally carried out in the range of 150 to 300 ° C.

The propylene-based resin composition for a multilayer stretched film of the present invention includes the modified propylene-based resin (A), a low-calorie propylene-based resin (B), preferably a propylene-based resin (C), and an ethylene-based elastomer (D). If it contains, it is not necessary to use it as an independent raw material. That is, a resin composition already containing two or more of these components can be used as a raw material, or a molded product already made of the resin composition can be crushed and used as a raw material. Further, when the raw material which is a resin composition in advance does not have all the components constituting the present invention, only the insufficient components may be supplemented as the raw material.

[Multilayer stretched film]
The multilayer stretched film of the present invention uses the propylene-based resin composition for a multilayer stretched film of the present invention as an adhesive resin, and adheres to the adhesive layer made of the propylene-based resin composition for a multilayer stretched film of the present invention. It has a polypropylene layer laminated on one surface of the layer, and a polyamide layer, an ethylene vinyl alcohol layer, or a polyester layer laminated on the other surface.

The polypropylene layer imparts rigidity and heat sealability to the multilayer stretched film as a base material layer, and the polyamide layer, ethylene vinyl alcohol layer, and polyester layer impart barrier properties to the multilayer stretched film as a barrier layer. ..

The layer structure of the multilayer stretched film comprises a polypropylene layer as a base material layer, a polyamide layer as a barrier layer, an ethylene vinyl alcohol layer, or an adhesive layer via an adhesive layer made of the propylene resin composition for a multilayer stretched film of the present invention. Any structure may have a structure in which polyester layers are laminated, and the structure is not limited to these three-layer laminated structures, but a five-layer laminated structure such as a base material layer / adhesive layer / barrier layer / adhesive layer / base material layer, or A multilayer laminated structure having a larger number of layers may be used.

The thickness of each layer varies depending on the material used, the characteristics required by the purpose of use, the number of layers, the draw ratio, and the like. Although there is no particular limitation, the thickness of each layer is the thickness before stretching, the thickness of the polypropylene layer of the base material layer is 20 to 300 μm, and the thickness of the polypropylene-based resin composition for a multilayer stretched film of the present invention serving as an adhesive layer The thickness of the layer is 2.5 to 100 μm, the thickness of the polyamide layer, ethylene vinyl alcohol layer, or polyester layer of the barrier layer is in the range of 5 to 200 μm, and the total thickness of the multilayer laminated film before stretching is 30 to 30 to 200 μm. The thickness is preferably 700 μm, and in the present invention, it is preferable that such a pre-stretched multilayer laminated film is stretched to obtain the multilayer stretched film of the present invention.

The method for producing the multilayer laminated film before stretching is not particularly limited, and polypropylene for the base material layer, the propylene-based resin composition for the multilayer stretched film of the present invention for the adhesive layer, polyamide for the barrier layer, ethylene vinyl alcohol, etc. Alternatively, it can be produced by various conventionally known methods using polyester. For example, coextrusion molding method, inflation molding method, blow molding method, rotary molding method, press molding method, injection molding method (insert injection molding method, two-color injection molding method, core back injection molding method, sandwich injection molding method, injection). Various molding methods such as press molding method) can be used. Above all, the coextrusion molding method is preferable because the excellent heat-sealing property and processability of the propylene-based resin composition for a multilayer stretched film of the present invention can be utilized and the productivity can be improved.

As a method for producing the propylene-based resin composition for a multilayer stretched film of the present invention by stretching the multilayer laminated film before stretching obtained as described above, various conventionally known methods can be adopted. it can. For example, the unstretched multilayer laminated film obtained by the above method is cooled and solidified, then reheated in-line or offline to a stretching temperature of 60 to 190 ° C., and uniaxially (longitudinal) using a tenter, a plug, compressed air, or the like. Alternatively, a method of stretching at least 1.5 times in area ratio in the biaxial (longitudinal and horizontal) directions to obtain a uniaxially or biaxially stretch-molded film can be mentioned. The draw ratio is usually 1.5 to 50 times, preferably 1.5 to 20 times in terms of area ratio. If the draw ratio is less than 1.5 times, the effect of stretching cannot be obtained, and if it exceeds 50 times, the strength of the multilayer stretched film tends to decrease, for example, breakage may occur during molding.

When producing an inflation film, a simultaneous inflation biaxial stretching method, in the case of a T-die film, a tenter simultaneous biaxial stretching method, a roll and tenter-based sequential biaxial stretching method, and the like can be adopted. It is also possible to manufacture cups by stretching. In that case, in the case of bottle manufacturing, such as pneumatic molding or vacuum molding with compressed air in the mold, SPPF molding using a plug and compressed air, etc., a laminated pipe is used. After stretching vertically, a test tubular bottomed parison is formed by a pipe stretching method that stretches horizontally with compressed air or the like in a mold, injection molding, and the bottomed parison is stretched vertically in a mold with a rod. A bottomed parison stretching method or the like in which stretching is performed in the lateral direction by compressed air or the like is generally used.

Further, the multilayer stretched film of the present invention can be further improved in heat resistance (slightly reduced in shrinkage) by performing reheating after stretching, that is, heat setting, if necessary. Further, the propylene-based resin composition for a multilayer stretched film of the present invention and a separately manufactured film can be laminated to form a laminated film.

[Packaging]
The package of the present invention has excellent transparency and can sufficiently maintain the adhesiveness between the base material layer and the barrier layer by the adhesive layer even after stretching, and is a beverage such as a soft drink or a fruit beverage. , Hams and sausages, favorite foods, edible oils, other foods, medical / pharmaceuticals, cosmetics and the like.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples as long as the gist of the present invention is not exceeded.

The resin raw materials used in the following examples and comparative examples are as follows.
^{The amount of graft of the modified propylene resin (A) is 1900 to 1600 cm -1} (C = O expansion and contraction vibration band) carbonyl characteristic as absorption peculiar to carboxylic acid or its derivative in the resin by using the infrared absorption spectrum method. Confirmed by measuring absorption.

-Modified propylene resin (A)
A modified propylene resin (A-1) produced by the following method was used.
In 6 L of chlorobenzene, 5 kg of powder of a propylene homopolymer (density 0.90 g / cm ³ , MFR (230 ° C., 2.16 kg) 10 g / 10 minutes) and 500 g of maleic anhydride were dissolved at 130 ° C. Then, a chlorobenzene solution (200 g / 400 L) of dicumyl peroxide was added to this solution. The reaction was further continued at 130 ° C. for 8 hours, then cooled to 40 ° C. to precipitate the resin. The precipitated resin was filtered, washed repeatedly with acetone, and dried under reduced pressure at 90 ° C. to obtain a modified propylene resin (A-1) having a graft amount of 2.5% by mass. The density of the modified propylene resin (A-1) was 0.89 g / cm ³ , the MFR (230 ° C, 2.16 kg) was 500 g / 10 minutes, and the amount of unreacted modifier according to the measurement method described later was below the lower limit of detection. It was.

・ Low heat of fusion propylene resin (B)
Low calorific value propylene resin (B-1): Mitsui Chemicals, Inc., product name "Toughmer XM7070" (comonomer (1-butene) unit content 30% by mass, MFR (230 ° C, 2.16 kg) 7 g / 10 minutes , Heat of fusion 40mJ / mg)
Low heat of fusion propylene resin (B-2): manufactured by Exxon Mobile Chemical Co., Ltd., product name "VISTAMAXX3000" (content of comonomer (ethylene) unit 11% by mass, MFR (230 ° C, 2.16 kg) 8 g / 10 minutes, Heat of fusion 25mJ / mg)
Low calorific value propylene resin (B-3): Mitsui Chemicals, Inc., product name "Toughmer PN2060" (content of comonomer (ethylene and 1-butene) unit 20 to 30% by mass, MFR (230 ° C, 2.16 kg) ) 6 g / 10 minutes, heat of fusion 15 mJ / mg)

-Propylene resin (C)
Propylene resin (C-1): Made by Japan Polypropylene Corporation, product name "Novatec PP EG7F" (content of comonomer (ethylene) unit less than 10% by mass, MFR (230 ° C, 2.16 kg) 1.5 g / 10 minutes , Heat of fusion 80mJ / mg)
Propylene resin (C-2): manufactured by Japan Polypropylene Corporation, product name "Novatec PP MA3" (homopolymer), MFR (230 ° C, 2.16 kg) 10 g / 10 minutes, heat of fusion 110 mJ / mg)

-Ethylene elastomer (D)
Ethylene elastomer (D-1): manufactured by Dow Chemical Co., Ltd., product name "Engage 7467" (density 0.862 g / cm ³ , MFR (190 ° C, 2.16 kg) 1.2 g / 10 minutes, melting peak temperature 34 ° C. )

[Example 1]
1) Preparation of propylene-based resin composition for multilayer stretched film The modified propylene-based resin (A), low calorific value propylene-based resin (B), propylene-based resin (C), and ethylene-based elastomer (D) shown in Table 1 Is used in the ratio shown in Table 1, and 0.01 parts by mass of a phenol-based antioxidant (SONGWON, SONGNOX1076) and a phosphorus-based antioxidant (SONGWON, SONGNOX1680) are further used for a total of 100 parts by mass. Add 0.05 parts by mass and dry blend, melt and knead with a single-screw screw extruder (manufactured by IKG, IKG50) at a cylinder temperature of 200 ° C., a screw rotation speed of 60 rpm, and an extrusion rate of 30 kg / h to form a strand. It was extruded, cooled, and cut into pellets to obtain a propylene-based resin composition 1 for a multilayer stretched film.

2) Polypropylene / propylene resin composition for multilayer stretched film / polyamide 6 Molding of multilayer laminated film Polypropylene / multilayer using the propylene resin composition 1 for multilayer stretched film obtained above and using a T-die molding machine. A three-kind five-layer laminated film of a propylene-based resin composition for a stretched film / polyamide 6 / a propylene-based resin composition for a multilayer stretched film / polypropylene was molded. A film having a total thickness of 300 μm was obtained with a layer structure of each layer having a thickness of 100/20/60/20/100 μm at a molding temperature of 240 ° C. and a line speed of 8 m / min. Homopolypropylene manufactured by Japan Polypropylene Corporation, product name "Novatec PP FY4" was used for the polypropylene layer, and "1020" manufactured by DSM was used for the polyamide 6 layer.

3) Polypropylene / Propylene Resin Composition for Multilayer Stretched Film / Polyamide 6 Stretch Molding of Laminated Multilayer Film The 3 types and 5 layer laminated film obtained above are preheated to 180 by a batch type biaxial stretching machine manufactured by Toyo Seiki Co., Ltd. A stretched film was obtained by stretching 3 times in each of the vertical and horizontal directions under the conditions of ° C., preheating time 1 minute, heat setting temperature 180 ° C., and heat setting time 1 minute.

4) Evaluation of Adhesive Strength In the film before and after stretching, the interlayer adhesive strength (N / 15 mm) between the propylene resin composition layer for the multilayer stretched film and the 6 layers of polyamide was measured under the following conditions.
Peeling width: 10 mm
Peeling angle: T peel Peeling speed: 300 mm / min
Measurement atmosphere temperature: 23 ° C

5) Measurement of the content of unreacted modifier The modified propylene resin (A) was molded into a thin section with a thickness of 100 μm at 200 ° C. using a heating press to obtain a sample-1 and placed in a Soxhlet extractor, and the sample was refluxed with acetone. After removing the unreacted modifier from the sample-2, Sample-2 was obtained by drying at 80 ° C. for 2 hours using a heat dryer.
The denaturant contents of Sample-1 and Sample-2 were determined from the absorbance ratio using an infrared spectrophotometer. The content of the unreacted denaturant was calculated by [content of unreacted denaturant] = [content of denaturant of sample-1]-[content of denaturant of sample-2].

[Examples 2 and 3]
In the preparation of the propylene-based resin composition 1 for the multilayer stretched film of Example 1, the propylene for the multilayer stretched film was the same as in Example 1 except that the propylene-based resin (B) having a low heat of fusion was used as shown in Table 1. The based resin compositions 2 and 3 were further prepared, film-molded and stretch-molded in the same manner as in Example 1, and the adhesive strength was evaluated in the same manner.

[Comparative Example 1]
In the preparation of the propylene-based resin composition 1 for the multilayer stretched film of Example 1, the amounts of the modified propylene-based resin (A) and the propylene-based resin (C) blended are shown in the table without using the low heat-melting propylene-based resin (B). A propylene-based resin composition 4 for a multilayer stretched film was prepared in the same manner as in Example 1 except that the changes were made as in 1. Further, film molding and stretching molding were performed in the same manner as in Example 1, and the adhesive strength was evaluated in the same manner. went.

The results obtained in Examples 1 to 3 and Comparative Example 1 are summarized in Table 1. All of the propylene-based resin compositions for multilayer stretched films were excellent in transparency.

As is clear from Table 1, in Examples 1 to 3, the adhesive strength after stretching is also high. This is because the low melting calorie propylene resin (B) is blended, so that the state in which the molecular chain of the modified propylene resin (A) is stretched by stretching can be relaxed or made difficult to stretch. It is presumed that the pseudo graft copolymer with the barrier resin was not eliminated even after stretching, and the adhesive strength could be maintained.

On the other hand, in Comparative Example 1, since the low calorific value propylene resin (B) was not blended, the molecular chain of the modified propylene resin (A) was stretched by stretching, and the molecular chain of the modified propylene resin (A) was stretched, which was different from that of the barrier resin. It is presumed that the adhesive strength after stretching could not be maintained due to the elimination of the pseudo graft copolymer.

The propylene resin composition for a multilayer stretched film of the present invention and the multilayer stretched film using the same are a specific modified propylene resin (A), a low calorific value propylene resin (B), and further a propylene resin (C). , An adhesive resin composition containing an ethylene-based elastomer (D), which has excellent transparency and exhibits excellent adhesive strength even after stretching in a multilayer stretched film with a base resin and a barrier resin. Therefore, the propylene-based resin composition for a multilayer stretched film of the present invention and the multilayer stretched film using the same can be suitably used as a packaging material for various foods, medical treatments, pharmaceuticals, and the like.

Claims (7)

A modified propylene-based resin (A) satisfying the following conditions (A-i) to (A-ii), and a low-calorie propylene-based resin (B) satisfying the following conditions (B-i) to (B-iv) . A multilayer stretched film containing a propylene-based resin (C) satisfying the following conditions (C-i) to (C-ii) and an ethylene-based elastomer (D) satisfying the following conditions (D-i) to (D-iii). a use propylene resin composition,
1 to 15% by mass of the modified propylene resin (A), 10 to 50% by mass of the low calorific value propylene resin (B), 20 to 84% by mass of the propylene resin (C), and an ethylene elastomer (D). A propylene-based resin composition for a multilayer stretched film containing 5 to 15% by mass.
(Ai) Graft the propylene resin with at least one compound selected from the group consisting of unsaturated carboxylic acids, unsaturated carboxylic acid derivatives, unsaturated silane compounds, and unsaturated epoxy compounds in the presence of a solvent. It is a modified modified polypropylene.
(A-ii) The amount of graft is in the range of 0.01 to 10% by mass.
(Bi) The amount of heat of fusion is in the range of 0 to 50 mJ / mg.
(B-ii) The melt flow rate (MFR: 230 ° C., 2.16 kg) is in the range of 0.5 to 75 g / 10 minutes.
(B-iii) A propylene-based copolymer having a propylene unit content in the range of 65 to 90% by mass and a comonomer unit content in the range of 10 to 35% by mass.
(B-iv) At least one comonomer selected from the group consisting of ethylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-heptene, 1-hexene, 1-octene and 1-nonene. Is.
(Ci) The amount of heat of fusion is in the range of more than 50 mJ / mg and 150 mJ / mg or less.
(C-ii) The melt flow rate (MFR: 230 ° C., 2.16 kg) is in the range of 0.5 to 20 g / 10 minutes.
(Di) The density is in the range of ^{0.850 to 0.910 g / cm 3.}
(D-ii) The melting peak temperature is not observed or is below 100 ° C.
(D-iii) The melt flow rate (MFR: 190 ° C., 2.16 kg) is in the range of 0.1 to 75 g / 10 minutes. The modified propylene resin (A) is obtained by modifying a propylene resin of any one of a propylene homopolymer, a propylene / ethylene copolymer, and a blend thereof with maleic acid or an anhydride thereof, and the melt flow rate thereof. The propylene-based resin for a multilayer stretched film according to claim 1, wherein (MFR: 180 ° C., 2.16 kg, orifice diameter 1 mm) is 1 to 1000 g / 10 minutes and the density is 0.86 to 0.93 g / cm ^3. Composition. The propylene resin composition for a multilayer stretched film according to claim 1 or 2, wherein the comonomer of the low calorific value propylene resin (B) is ethylene and / or 1-butene. Propylene resin (C) is a homopolymer of propylene, based on any one of a copolymer of propylene with ethylene and / or 1-butene, claim 1, wherein the content of the propylene units is 90 wt% or more The propylene-based resin composition for a multilayer stretched film according to any one of 3 to 3. The ethylene-based elastomer (D) is an ethylene-propylene copolymer rubber having a propylene unit content of 15 to 65% by mass, or a propylene unit content of 15 to 65% by mass and a non-conjugated diene unit content. The propylene-based resin composition for a multilayer stretched film according to any one of claims 1 to 4, wherein is 1 to 25% by mass of an ethylene / propylene / non-conjugated diene copolymer rubber. An adhesive layer made of the propylene-based resin composition for a multilayer stretched film according to any one of claims 1 to 5 , a polypropylene layer laminated on one surface of the adhesive layer, and a laminate on the other surface. A multilayer stretched film having a polyamide layer, an ethylene vinyl alcohol layer, or a polyester layer. A packaging body using the multilayer stretched film according to claim 6.