JP3271301B2 - Laminated film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a laminated film comprising at least two layers. More specifically, the present invention relates to a laminated film having flexibility, heat resistance, stiffness, mechanical strength, low-temperature heat sealability, and the like, as a soft film comparable to a soft vinyl chloride film or a vinylon film.

[0002]

2. Description of the Related Art In recent years, a soft vinyl chloride film containing a plasticizer has been widely used as a soft film. However, the soft vinyl chloride resin has social factors such as toxicity and transfer problems due to bleed-out of plasticizers and monomers, and acid rain problems due to generation of hydrogen chloride during incineration.

On the other hand, as a soft film similar to the above-mentioned soft vinyl chloride film, there is a film mainly composed of ethylene such as an ethylene / vinyl acetate copolymer, a low-density polyethylene and an ionomer. However, such a soft film mainly composed of ethylene is inferior to a soft vinyl chloride film in terms of transparency, haze, gloss, and the like, and also has a drawback that it is inferior in heat resistance and stiffness.

[0004]

SUMMARY OF THE INVENTION In view of the above circumstances, the present invention has good transparency, haze, gloss, etc., and has excellent flexibility, heat resistance, stiffness, low-temperature heat sealability, and the like. The purpose is to provide excellent films. Further, the present invention is characterized by the above, from various uses, for example, food packaging,
Films for packaging such as fiber packaging, medical applications such as infusion bags, metal protective films, base materials for adhesive tapes, civil engineering
An object of the present invention is to provide a film suitably used as a film for building materials in the field of construction. The inventors have conducted intensive studies for the above purpose, and as a result, an amorphous polyolefin having a specific composition, or a layer formed by mixing the amorphous polyolefin and crystalline polypropylene at a predetermined ratio, and an ethylene-based resin. A laminated film composed of
The present inventors have found that a film in which a layer made of an ethylene-based resin constitutes at least one of the outermost layers of the film is suitable for the above object, and completed the present invention.

[0005]

According to the present invention, (A)
20 to 100% by weight of an amorphous polyolefin having a propylene and / or butene-1 component content of 50% by weight or more
(Excluding 100% by weight) and crystalline polypropylene 80
A layer composed of a resin composition containing 〜0% by weight (excluding 0% by weight), and (B) a density of 0.895 g / cm ³ 〜
0.93 g / cm ³ ethylene resin (however,
Down - a layer consisting of an unsaturated carboxylic acid ester is excluded) is in the film is laminated on at least three layers, and a laminated film both the outside surfaces layer are constituted by the (B) layer, laminate Tensile modulus of film (vertical, 23
C.) in the range of 113 to 1014 (kg / cm ² ). In the present invention, the number average molecular weight of the amorphous polyolefin (A) having a propylene and / or butene-1 component content of 50% by weight or more is in the range of 1,500 to 100,000, and boiling n-heptane Is preferably 60% by weight or less, the dart impact of the laminated film is 422 (g / 26 inch) or more, and the Elmendorf tear strength (longitudinal) of the laminated film is:
The tensile elasticity ratio (longitudinal, 80 ° C / 23 ° C) of the laminated film is in the range of 59 to 160 (kg / cm),
0.30, and the tensile elongation of the laminated film (vertical, 2
3 ° C.) is preferably in the range of 610 to 870 (%). A multilayer film in which both outer layers of the layer (A) are made of crystalline polypropylene has already been filed by the same applicant as Japanese Patent Application No. 3-241238. The present invention has been obtained by further studying the above invention.

[0006]

The laminated film of the present invention is constituted as described above, and has a layer composed of an amorphous polyolefin having a propylene and / or butene-1 content of 50% by weight or more and a crystalline polypropylene, and having a density of 0%. 0.895 g / cm ^{3 to} 0.
93 g / cm ³ of ethylene resin (however, ethylene-
(Excluding unsaturated carboxylic acid esters) , and by co-extrusion or lamination to form a composite.
Excellent transparency, haze, gloss, flexibility and heat resistance,
The resulting film has excellent stiffness and low-temperature heat sealability.

Hereinafter, the present invention will be described in detail. The amorphous polyolefin used in the layer (A) of the present invention (hereinafter referred to as “amorphous polyolefin”) is an amorphous polyolefin having a propylene and / or butene-1 content of 50% by weight or more. Any olefin polymer may be used. For example, amorphous polypropylene or polybutene-1 or a copolymer of propylene or butene-1 with another α-olefin can be used. Propylene and / or butene-1 content of amorphous polyolefin is 50% by weight
If it is less than 1, the compatibility with the crystalline polypropylene is undesirably reduced.

The above-mentioned amorphous polyolefin refers to a boiling n-
Heptane insoluble content, that is, Soxhlet extracted insoluble content with boiling n-heptane is 70% by weight or less, preferably 6% by weight.
0% by weight or less. If the boiling n-heptane insoluble content is more than 70% by weight, the ratio of the amorphous portion becomes small, and the obtained film cannot be provided with the desired flexibility. Further, the above-mentioned amorphous polyolefin of the layer (A) preferably has a number average molecular weight of 1,000.
~ 200,000, more preferably 1,500 ~ 10
It is 0000. When the number average molecular weight exceeds 200,000, film formation is difficult, and when it is less than 1,000, the mechanical strength decreases. In the present invention, the above-mentioned amorphous polyolefins can be used alone or in combination of two or more.

As the amorphous polypropylene, atactic polypropylene produced as a by-product during the production of crystalline polypropylene may be used, or it may be used as it is produced from raw materials. At this time, propylene or butene-1 and other α
-The copolymer with olefin can be produced from a raw material so as to contain a predetermined propylene or butene-1 component and used. In the case of target production, for example, it can be obtained by polymerizing a raw material monomer in the presence of hydrogen and / or in the absence of hydrogen using a titanium-supported catalyst supported on magnesium chloride and triethylaluminum. From the viewpoint of the stability of raw material supply and the stability of quality, it is preferable to use a predetermined amorphous polyolefin produced for the purpose. In addition, if there is a corresponding suitable commercial product, a commercial product can be appropriately selected and used.

As the amorphous polyolefin of the layer (A) of the present invention, specifically, polypropylene, propylene / ethylene copolymer, propylene / butene-1 copolymer having predetermined characteristics such as the above-mentioned propylene content. Propylene / butene-1 / ethylene-3 terpolymer, propylene / hexene-1 / octene-1 / 3 terpolymer, propylene / hexene-1 / 4-methylpentene-1 / 3 terpolymer and the like Amorphous polyolefin containing propylene component as a main component. In addition, polybutene-1, butene-1 · having predetermined characteristics such as the above-mentioned butene-1 component content.
Ethylene copolymer, butene-1 / propylene copolymer,
Butene-1, propylene, ethylene terpolymer, butene-1, hexene-1, octene-1, terpolymer, butene-1, hexene-1, 4-methylpentene
Amorphous polyolefins whose main component is a butene-1 component such as a terpolymer is also exemplified. When the amorphous polyolefin is a propylene / ethylene copolymer, the ethylene component content is 0 to 30% by weight, preferably 1 to 20%.
% By weight is desirable. When the ethylene content is 30
If it is larger than the weight percentage, the obtained film becomes too soft.

When the amorphous polyolefin of the layer (A) of the present invention is a propylene / butene-1 copolymer, a copolymer containing propylene as a main component and a copolymer containing butene-1 as a main component are used. , Propylene and butene-1 as main components. It is desirable that the content of these main components is 50% by weight or more and the remaining components are less than 50% by weight, preferably 1 to 45% by weight, more preferably 5 to 44% by weight. propylene·
All butene-1 copolymers have high tensile elongation, rebound resilience, and cohesion, and can be optionally used as an amorphous polyolefin for the (A) layer. Specifically, for example, a commercially available product such as REXTAC of Rexene of the United States can be used.

The crystalline polypropylene used in the layer (A) of the present invention includes polypropylene which is generally commercially available for extrusion molding, injection molding, blow molding and the like, and is prepared from isotactic polypropylene which is insoluble in boiling n-heptane. Say. In this case, a propylene homopolymer may be used, or a copolymer of isotactic polypropylene having stereoregularity and another α-olefin may be used.
The crystalline polypropylene may be a commercially available product, or may be manufactured and used. The method for producing crystalline polypropylene is not particularly limited, and can be appropriately selected from conventional methods for producing crystalline polypropylene and applied.

The α-olefin used for copolymerization with crystalline polypropylene includes α-olefins having 2 to 8 carbon atoms.
-Olefins, such as ethylene, butene-1, pentene-1, hexene-1, heptene-1, octene-1 and the like are preferred. Among these, ethylene or butene-1 is particularly preferable.

In the present invention, the crystalline polypropylene is preferably a propylene homopolymer, a random copolymer or block copolymer of propylene / ethylene containing an ethylene component of 30% by weight or less, preferably 1 to 25% by weight. And a random copolymer or block copolymer of propylene / butene-1 containing 20% by weight or less of butene-1. Among them, a copolymer of ethylene or butene-1 and propylene is particularly preferable from the application of the resin composition of the present invention such as a film or sheet. The crystalline polypropylene of the layer (A) can be used alone or in combination of two or more.

Further, in the present invention, the amorphous polyolefin and / or the crystalline polypropylene of the layer (A) comprises:
Modified ones can be used. The above amorphous polyolefin or crystalline polypropylene is, for example, unsaturated carboxylic acid such as acrylic acid, methacrylic acid, ethacrylic acid, maleic acid, fumaric acid, itaconic acid and / or
Alternatively, they can be used after being modified with derivatives thereof such as esters, acid anhydrides, metal salts and the like, unsaturated amides, amino compounds, glycidyl methacrylate, hydroxy methacrylate and the like. Of these denatured products,
Those modified with maleic anhydride and itaconic anhydride are preferably used, and those modified with maleic anhydride are more preferably used.

In the present invention, the method for preparing the resin composition in which the amorphous polyolefin of the layer (A) and the crystalline polypropylene are blended is not particularly limited, and is commonly used in the conventional method for producing a polypropylene composition. For example, it can be carried out by heat-melting kneading using a kneader such as a kneader, a Banbury mixer, a roll, or a single-screw or twin-screw extruder. In the present invention, the above (A)
Various additives and fillers as required in the resin composition constituting the layer, for example, heat stabilizers, antioxidants, light stabilizers, antistatic agents, lubricants, nucleating agents, flame retardants, pigments or dyes, carbonic acid Calcium, calcium sulfate, barium sulfate, magnesium hydroxide, mica, talc, clay and the like can be added. Furthermore, other thermoplastic resins, thermoplastic elastomers, rubbers and the like can be blended as necessary, and these can be crosslinked. In particular, when imparting flame retardancy, magnesium hydroxide and magnesium carbonate are used in a range of 20 to 60 with respect to the multilayer film.
It is added in parts by weight.

The resin composition of the layer (A) of the present invention comprises the above-mentioned amorphous polyolefin alone or the above-mentioned amorphous polyolefin and crystalline polypropylene, and contains the amorphous polyolefin in an amount of 20 to 100% by weight (100 % by weight). %) ,
Preferably 25 to 100% by weight (excluding 100% by weight)
It can be obtained by blending such that If the amount of the amorphous polyolefin is less than 20% by weight, sufficient flexibility cannot be obtained.

The ethylene resin used in the layer (B) of the present invention has a density of 0.895 g / cm ^{3 to} 0.93 g.
Of / cm ³ I ethylene resin der, ethylene - unsaturated
Ru ethylene resin der except carboxylic acid ester. Concrete
Specifically , low-density polyethylene, linear low-density polyethylene, ultra-low-density polyethylene, medium-density polyethylene, and copolymers containing ethylene as a main component, that is, ethylene and propylene, butene, pentene, hexene, heptene, octene, etc. And copolymers or multipolymers with one or more comonomers selected from olefins and vinyl esters such as vinyl acetate and vinyl propionate. Of course, two or more kinds of polymers or copolymers may be used as a mixture. In addition, a modified material similar to the layer (A) can be used.

These materials have a density of 0.895 g / cm ^{3 to} 0.1 g / cm ³ .
Among the ethylene-based resin of 93 g / cm ^3, from the viewpoint of flexibility of the entire multilayer film, the Shore D hardness at 23 ° C. 5
Those having a value of 0 or less are particularly preferred. Examples of those having a Shore D hardness of 50 or less include low-density polyethylene, linear low-density polyethylene, ultra-low-density polyethylene, and ethylene / vinyl acetate copolymer.

The laminated film of the present invention has the above-mentioned (A)
The layers (B) and (B) are usually laminated alternately, and the number of laminated (A) and (B) layers is not particularly limited, but is composed of at least three layers , and the outermost layer, that is, The layers forming both outer surfaces are constituted by the layer (B). For example, (B) / (A) / (B) and, (B)
A laminated film can be constituted by a laminated combination such as / (A) / (B) / (A) / (B).

In the present invention, the layer (A) contributes to imparting flexibility to the whole film, and can also exhibit heat resistance and stiffness of the film by containing crystalline polypropylene. However, the amorphous polyolefin used has a strong surface tackiness, especially when the molecular weight is low. On the other hand, the (B) layer contributes to the flexibility and low-temperature heat sealability of the film, since there is little surface tack, as described above (B) layer is
So as to constitute the both outer layers, (A) layer by forming the inner layer side, it is possible both outer layers is a surface tack-free flexible film. Further, the laminated film of the present invention,
Even if another thermoplastic resin layer, for example, nylon, polyvinyl alcohol, saponified ethylene / vinyl acetate copolymer, polyester, or the like for providing a gas barrier is inserted between the layers (A) and (B). Good.

In the present invention, the thickness of each layer constituting the laminated film is not particularly limited, and can be arbitrarily selected. Usually, each layer is about 2-1000 μm
Formed in the range. Further, the ratio of the thickness of the layer (A) to the thickness of the layer (B) is not particularly limited. Preferably, as described above, layer (A) contributes to the flexibility of the film,
Since the (B) layer fulfills the function of preventing surface tackiness, the total thickness of the (A) layers obtained by summing the thicknesses of the respective (A) layers constituting the film is 20 to 99% of the thickness of the laminated film, and Preferably, it is configured to be 30 to 95%.

The method for producing the laminated film of the present invention is not particularly limited. For example, a coextrusion lamination method, a lamination method, a dry lamination method, or the like can be used. Of these, the co-extrusion lamination method in which melt bonding is performed is preferred. Specifically, for example, melt extrusion using an extruder suitable for the number of laminations, after laminating in a molten state by a known method such as T-die method or inflation method, using a cooling roll, a method of cooling with water or air cooling. Thus, a laminated film can be obtained.

The laminated film of the present invention can be subjected to a surface treatment in order to improve printability, lamination, and adhesive application properties. Examples of the surface treatment method include a corona discharge treatment, a plasma treatment, a flame treatment, and an acid treatment. In the present invention, any of the methods can be used.
Since continuous processing is possible and can be easily performed before the winding step in the film manufacturing process, plasma processing,
A flame treatment and a corona discharge treatment are preferred, and among these, a corona discharge treatment is most preferred in terms of simplicity. In addition, the present laminated film can be subjected to uniaxial or biaxial stretching, compressed air, vacuum forming, or the like.

The laminated film of the present invention is laminated, cooled, and solidified as described above, subjected to the above-described treatment as necessary, and then wound up to a next step, for example, printing, laminating, and adhesive. It can be used for the intended use through secondary processing steps such as coating and heat sealing. The laminated film of the present invention is applicable and useful for various applications by itself, but is further laminated with polyester, nylon, stretched polypropylene film, etc., and has a mechanical strength,
Functions such as gas barrier properties and printing performance can also be improved.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to embodiments. However, the present invention is not limited by the following examples. In the following examples of the present invention, measurement of each inspection item was performed by the following method.

[Tensile properties] The tensile test was conducted according to JIS-Z17.
(1) Tensile yield strength (kg / c
m ² ), (2) Tensile breaking strength (kg / cm ² ), (3) Tensile elongation (%), (4) Tensile modulus (kg / cm ² )
The items were evaluated. [Haze: Haze (%)] Performed according to ASTM D1003. [Gloss (%)] Performed according to ASTM D2457. [Elmendorf tear strength (kg / cm)] This was performed according to JIS-P8116. [Dirt Impact (g / 26 in)] The measurement was performed according to ASTM D1709. (Heat seal temperature) heat seal at a predetermined temperature,
The minimum temperature at which the adhesive strength to break the material was obtained was defined as the heat sealing temperature.

Example 1 [Preparation of (A) Layer Resin Composition] As the resin composition constituting the (A) layer, the density was 0.86 g / cm ³ , the propylene content was 65% by weight, and the butene-1 content was 35. % By weight, amorphous polyolefin having a melt viscosity of 10,000 cps (190 ° C.) (trade name: REXTAC RT278, manufactured by Lexen Co., Ltd.)
0) and a crystalline polypropylene (trade name B301H, manufactured by Ube Industries, Ltd.) having a density of 0.90 g / cm ³ and a melt flow rate (MFR) (230 ° C.) of 1.0 g / 10 min. Mixed at a weight ratio of 50 and at a temperature of 200 ° C. for 30
A resin composition prepared by melt-kneading for one minute was used.

[Formation of Laminated Film] The resin composition prepared above was added to the layer (A) and the density was 0.92 g / c.
m ³ , melt index (MI) (190 ° C.) = 2 g
A low-density polyethylene (manufactured by Ube Industries, Ltd., trade name: F200) of / 10 min was used for the layer (B). As the outer layer / intermediate layer / inner layer, (B) / (A) / (B) were adjusted to have the thickness ratios shown in Table 1, and three independent extruders each having three layers and a three-layer die connected thereto were used. Using, after co-extrusion of three layers of melt,
It was rapidly cooled by an air ring and a water-cooled sizing ring, blow-down molded into a tubular film, and immediately wound up to obtain a three-layer laminated film having a total thickness shown in Table 1. The properties of the obtained three-layer laminated film were measured, and the results are shown in Table 2. Table 1 shows the film composition.

Example 2 The layer (B) had a density of 0.92 g / cm ³ and MI (190 ° C.).
= 1.0 g / 10 min linear low density polyethylene (LLD
A three-layer laminated film having the total thickness shown in Table 1 was obtained in the same manner as in Example 1 except that PE) (manufactured by Ube Industries, Ltd., trade name: FA120N) was used. The properties of the obtained three-layer laminated film were measured, and the results are shown in Table 2. Table 1 shows the film composition.

Example 3 The layer (B) had a density of 0.895 g / cm ³ and an MI (190
° C) = 3.0 g / 10 min ultra low density polyethylene (VL
DPE) (trade name Z522, manufactured by Ube Industries, Ltd.) except that 3% of the total thickness shown in Table 1 was used in the same manner as in Example 1.
A layer laminated film was obtained. The properties of the obtained three-layer laminated film were measured, and the results are shown in Table 2. Table 1 shows the film composition.

Example 4 The layer (B) had a density of 0.93 g / cm ³ and MI (190 ° C.).
= 2.0 g / 10 minutes, ethylene-vinyl acetate copolymer (EVA) having a vinyl acetate content of 15% by weight (manufactured by Ube Industries, Ltd.)
A three-layer laminated film having the entire thickness shown in Table 1 was obtained in the same manner as in Example 1 except that V215) was used. The properties of the obtained three-layer laminated film were measured, and the results are shown in Table 2.
It was shown to. Table 1 shows the film composition.

Comparative Example 1 The resin used for the (B) layer was a resin having a density of 0.91 g / cm ³ and a melt flow rate (MFR) (230 ° C.) = 9 g / 10.
138 ° C crystalline polypropylene (Ube Industries, Ltd.)
A three-layer laminated film having the entire thickness shown in Table 1 was obtained in the same manner as in Example 1 except that the trade name was RF395 (trade name, manufactured by Co., Ltd.). The properties of the obtained three-layer laminated film were measured, and the results are shown in Table 2. Table 1 shows the film composition.

Comparative Example 2 The same procedure as in Comparative Example 1 was carried out except that the resin used for the layer (A) was changed to a mixing ratio of amorphous polypropylene and crystalline polypropylene of 7/3. A layer laminated film was obtained. The properties of the obtained three-layer laminated film were measured,
The results are shown in Table 2. Table 1 shows the film composition.

Comparative Example 3 As a film raw material, a density of 0.93 g / cm ³ , MI
(190 ° C.) = 2.0 g / 10 min, vinyl acetate content 15
Using a weight-% ethylene-vinyl acetate copolymer (EVA) (trade name: V215, manufactured by Ube Industries, Ltd.), winding a tubular film using an inflation film forming apparatus equipped with an extruder and a ring-shaped die. And an EVA monolayer film having a thickness of 60 μm was obtained. The properties of the obtained film were measured, and the results are shown in Table 2.

Comparative Example 4 Low-density polyethylene (trade name: F200, manufactured by Ube Industries, Ltd.) having a density of 0.92 g / cm ³ and a melt index (MI) (190 ° C.) of 2 g / 10 minutes was used as a film raw material.
A LDPE single-layer film was obtained in the same manner as in Comparative Example 3 except that was used. The properties of the obtained film were measured, and the results are shown in Table 2.

Comparative Example 5 As a film raw material, a density of 0.92 g / cm ³ , MI
(190 ° C.) = 1.0 g / 10 min linear low density polyethylene (LLDPE) (manufactured by Ube Industries, Ltd., trade name FA12)
0N), except that LLDP was used in the same manner as in Comparative Example 3.
E monolayer film was obtained. The properties of the obtained film were measured, and the results are shown in Table 2.

Comparative Example 6 As a film raw material, a density of 0.91 g / cm ³ , a melt flow rate (MFR) (230 ° C.) = 9 g / 10 minutes,
A PP single-layer film was obtained in the same manner as in Comparative Example 3, except that crystalline polypropylene (PP) having a melting point of 138 ° C. (trade name: RF395, manufactured by Ube Industries, Ltd.) was used. The properties of the obtained film were measured, and the results are shown in Table 2.

[0039]

[Table 1]

[0040]

[Table 2]

From the above Examples and Comparative Examples, the three-layer laminated film composed of the layers (A) and (B) of the present invention has a better balance of flexibility, heat resistance and mechanical strength than the film of the Comparative Example. It can be seen that the low-temperature heat sealing is possible.

[0042]

The laminated film of the present invention is a flexible film having good transparency, haze and gloss, and excellent in flexibility, heat resistance, stiffness, mechanical strength and low-temperature heat sealability. Instead of the soft vinyl chloride film, which has become a social problem due to environmental pollution, it can be applied to various uses.

Continuation of the front page (72) Inventor Isao Nagayasu 3-1 Chikko Shinmachi, Sakai City, Osaka Prefecture Ube Industries, Ltd. Sakai Plant (56) References JP-A-3-16947 (JP, A) JP-A-58-126157 (JP, A) JP-A-58-171952 (JP, A) JP-A-64-1535 (JP, A) JP-A-1-18633 (JP, A) JP-A-5-237977 (JP, A) ( 58) Field surveyed (Int. Cl. ⁷ , DB name) B32B 1/00-35/00

Claims (6)

(57) [Claims] (A) propylene and / or butene-1
Resin composition containing 20 to 100% by weight (excluding 100% by weight) of amorphous polyolefin having a component content of 50% by weight or more and 80 to 0% by weight (excluding 0% by weight) of crystalline polypropylene And (B) a density of 0.
895 g / cm ^{3 to} 0.93 g / cm ³ ethylene resin
(However, ethylene-unsaturated carboxylic acid esters are excluded.
) Is a film laminated on at least three layers, and a laminated film in which both outer surface layers are constituted by the layer (B), wherein the tensile elastic modulus (longitudinal, 23 ° C.) is 113 to 1014 (kg / cm
² ) A laminated film characterized by the above-mentioned range. 2. (A) propylene and / or butene-1
The amorphous polyolefin having a component content of 50% by weight or more has a number average molecular weight in the range of 1,500 to 100,000, and the insoluble content of Soxhlet extracted with boiling n-heptane is 60% by weight or less. The laminated film according to claim 1, wherein 3. The dart impact of the laminated film is 4
The laminated film according to claim 1, wherein the thickness is 22 (g / 26 inch) or more. 4. The laminated film according to claim 1, wherein the Elmendorf tear strength (longitudinal) of the laminated film is in the range of 59 to 160 (kg / cm). 5. The tensile modulus ratio of the laminated film (vertical, 8
(0 ° C / 23 ° C) is in the range of 0.12 to 0.30. The laminated film according to any one of claims 1 to 4, wherein 6. Tensile elongation of laminated film (longitudinal, 23 ° C.)
Is in the range of 610 to 870 (%), The laminated film according to any one of claims 1 to 5, wherein