JP2009184252A - Polypropylene film for metal vapor deposition and metallized polypropylene film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tenacious polypropylene film for metal vapor deposition which shows superior adhesive properties with a metal vapor deposited layer during metal vapor deposition and outstanding surface cleavage resistance and material rupture resistance, and a metallized polypropylene film using the polypropylene film for metal vapor deposition. <P>SOLUTION: This polypropylene film for metal vapor deposition is structured of at least, two layers, i.e. a polypropylene resin laywr (A) and a polyolefin-based resin layer (B) containing a propylene-based copolymer with 149 to 159°C melt point. The element composition ratio (O/C) of oxygen (O) and carbon (C) in the surface of the polyolefin resin layer (B) is 0.2 to 0.4, and the coefficient of plane orientation (Fn) represented by formula (1) Fn=(MDn+TDn)/2-ZDn is 0.013 to 0.020 for the polypropylene resin layer (A) and 0.005 to 0.012 for the polyolefin-based resin layer (B). MDn is the index of refraction, in the MD (longer) direction, of the film; TDn is the index of refraction, in the TD (width) direction. of the film; and ZDn is the index of refraction, in the ZD (thickness) direction, of the film. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a polypropylene film used for packaging and industrial purposes, and particularly has excellent adhesion to a metal vapor deposition layer when metal vapor deposition is performed, and is excellent in anti-surface cleaving property and anti-material fracture resistance. The present invention relates to a polypropylene film for metal deposition and a metallized polypropylene film.

  A biaxially oriented polypropylene film (hereinafter referred to as OPP) is lightweight and excellent in mechanical properties, and thus is preferably used for packaging applications and industrial applications. Specific examples include food packaging bags for snacks and confectionery, packaging bags for pharmaceuticals, label packaging for liquid containers, and base film such as adhesive tape.

  And in order to improve barrier properties, such as water vapor | steam and oxygen of OPP, or to give designability, metal thin films, such as aluminum, zinc, nickel, and tin, are provided in the surface of OPP, and are used. Especially for snacks and confectionery, the quality of the contents deteriorates due to moisture absorption and oxidation, so metal and / or metal oxide is provided on the OPP surface to increase the gas barrier property of the packaging bag, and it is designed for label packaging of bottles In order to improve the property, a metal vapor deposition layer is provided and used.

  In such applications, adhesion between the OPP and the vapor deposition layer is important, but since polypropylene is basically composed of only carbon and hydrogen, the surface energy is small and the adhesion to the metal layer is low. It is weak and easily peels off.

  For this reason, there is a technology for increasing surface energy and improving adhesiveness by introducing oxygen and / or nitrogen into the OPP surface by surface treatment such as corona discharge treatment, plasma treatment, flame treatment, and combinations thereof. Used. When the functional groups introduced by these treatments are observed by XPS, oxygen and nitrogen belonging to a carboxyl group, a carbonyl group, an amino group, etc. are observed as a group bonded to a carbon atom.

  Although such surface treatment can improve the adhesiveness, it is not always sufficient, and as a method for further improving the adhesiveness, there is exemplified a method for reducing the crystallinity of polypropylene on the surface to be subjected to the surface treatment. . Specifically, the core is a copolymerized polypropylene (hereinafter, low crystalline polypropylene) obtained by copolymerizing α-olefin such as ethylene, butene-1, hexene-1, and 3methylbutene-1, which lowers the stereoregularity of polypropylene. It is a method of laminating on the surface of a polypropylene resin layer and applying the surface treatment to the surface of the low crystalline polypropylene (Patent Documents 1 to 3).

However, if the low crystalline polypropylene is simply laminated on the polypropylene resin layer as the core, the surface of the low crystalline polypropylene layer is roughened due to the heat received during metal deposition, and the glossiness decreases. When the laminate film containing the metal vapor-deposited film is produced, there is a problem that the laminate film breaks (cleaves) with the low crystalline polypropylene layer as a starting point.
Japanese Patent Laying-Open No. 2005-263896 (Claims, Claim 2) JP-A-6-287747 (Claims, Claim 1) JP-A-7-266516 (Claims, Claim 1)

  The present invention has been made in view of the background of such a conventional technique, and is excellent in adhesion to a metal vapor deposition layer when metal vapor deposition is performed, and is used for tough metal vapor deposition having excellent anti-surface cleaving property and anti-material breakability. It is an object to provide a polypropylene film and a metallized polypropylene film.

  The present invention proposes the following means in order to achieve the above object.

  (1) It has at least two layers of a polypropylene resin layer (A) and a polyolefin resin layer (B) containing a propylene copolymer having a melting point of 149 to 159 ° C., and the polyolefin resin layer (B) The elemental composition ratio (O / C) of oxygen (O) and carbon (C) on the surface is 0.2 to 0.4, and the plane orientation coefficient (Fn) represented by the following formula (1) is a polypropylene resin layer. (A) 0.013-0.020 in a polyolefin resin layer (B), and a polypropylene film for metal vapor deposition which is 0.005-0.012.

Fn = (MDn + TDn) / 2−ZDn (1)
MDn: refractive index in the MD (longitudinal) direction of the film
TDn: refractive index in the TD (width) direction of the film
ZDn: refractive index in the ZD (thickness) direction of the film (2) The total amount of organic and / or inorganic fillers contained in the polyolefin resin layer (B) is 300 to 1,500 ppm (mass basis) ( The polypropylene film for metal vapor deposition as described in 1).

  (3) The polyolefin resin layer (B) contains 1 to 10% by mass of a cold xylene soluble part, and the mass average molecular weight of the cold xylene soluble part is 10,000 or more. The polypropylene film for metal vapor deposition as described in 2).

  (4) The polypropylene film for metal vapor deposition according to any one of (1) to (3), wherein the thickness is 40 to 75 μm.

  (5) A metal vapor deposition layer is provided on the surface of the polyolefin resin layer (B) of the polypropylene film for metal vapor deposition according to any one of (1) to (4), and the thickness of the metal vapor deposition layer is 100. Metalized polypropylene film that is ~ 800 angstroms.

  The film of the present invention has the following effects when used for packaging and industrial purposes.

  (1) When metal deposition is performed, the adhesion to the metal deposition layer and the glossiness are excellent.

  (2) Since the surface cleaving property and the anti-material breakability are excellent, a highly durable laminate film can be constituted.

  The polypropylene film for metal vapor deposition of the present invention (hereinafter sometimes simply referred to as the polypropylene film of the present invention or the film of the present invention) and the metallized polypropylene film using the same will be described below.

  The polypropylene film of the present invention has at least a two-layer structure of a polypropylene resin layer (A) and a polyolefin resin layer (B) containing a polypropylene copolymer (in the following, the polypropylene resin layer (A ) May be referred to as layer (A) or resin layer (A), and polyolefin resin layer (B) may be referred to as layer (B) or resin layer (B)).

  The polypropylene resin constituting the layer (A) constitutes the base layer of the film of the present invention, and in order to impart excellent mechanical properties and heat resistance, the resin preferably has a melting point of 155 to 170 ° C. More preferably, it is 158-165 degreeC. Further, the resin may be a homopolymer composed only of propylene, or may be a copolymer of olefins and propylene selected from either ethylene or α-olefin. Among these, a particularly preferable polypropylene resin is a copolymer containing propylene and butene-1 as structural units, and is preferably a copolymer containing 0.1 to 5% by mass of polybutene-1. It is particularly preferable that polybutene-1 is 0.5 to 3% by mass. If polybutene-1 is less than 0.1% by mass, the thickness unevenness will increase in the biaxial stretching process of the film of the present invention, causing tarmi, etc. in the vapor deposition process, resulting in poor adhesion to the cooling can, such as cloudiness on the vapor deposition surface. May cause problems. On the other hand, if the polybutene-1 exceeds 5% by mass, the rigidity and heat resistance of the film is lowered, which may cause a problem during processing. In addition, the composition ratio of polybutene-1 in the copolymer is expressed in the form of mass% (content) as described above. The measuring method will be described later.

  The layer (A) can contain a known heat stabilizer, antioxidant, etc. to prevent deterioration of the polypropylene resin, and calcium stearate to neutralize residual chlorine as a catalyst residue. Further, metal soap such as calcium erucate and hydrotalcite can be contained as a chlorine scavenger. In particular, it is preferable to add an inorganic salt exemplified by hydrotalcites as the chlorine scavenger because it can reduce the generation of foreign matter in the film.

  In addition, for the purpose of improving the slipperiness of the film and improving processability, inorganic particles such as silicon oxide, calcium carbonate, aluminum oxide and titanium oxide having a particle size of 0.5 to 5 μm, polymethyl methacrylate, benzoguanamine Further, crosslinked resin particles such as polystyrene can be contained. The content is preferably from 300 to 3,000 ppm (mass basis), since good slip properties are obtained and transparency is hardly impaired, and particularly preferably from 500 to 2,000 ppm (mass basis).

  Moreover, it is important that the plane orientation coefficient (Fn) of the layer (A) is 0.013 to 0.020, and preferably 0.013 to 0.016. If the plane orientation coefficient (Fn) is less than 0.013, the rigidity and heat resistance of the film may be reduced, which may cause problems during processing. On the other hand, when the plane orientation coefficient (Fn) exceeds 0.020, since the orientation is too high during the production of the film, the stretchability is inferior, the film breaks frequently, the productivity may decrease, and the layer (B) / Since the difference in the degree of plane orientation of the layer (A) is large, cleavage may occur in the layer (B) / layer (A) when an impact is applied to the film surface by a cellophane tape peeling test or the like.

  The plane orientation coefficient (Fn) of the layer (A) can be controlled by the amount of heat applied to the layer (A) in the film stretching step. When the amount of heat applied to the layer (A) is large, the plane orientation coefficient (Fn) of the layer (A) decreases, and when the amount of heat applied to the layer (A) is small, the surface orientation coefficient (Fn) of the layer (A) is decreased. In order to increase the plane orientation coefficient (Fn) of the layer (A) within this range, the temperature condition of the film stretching process may be adjusted as appropriate.

  In the above, the plane orientation coefficient (Fn) is a value represented by the following formula (1).

Fn = (MDn + TDn) / 2−ZDn (1)
MDn: refractive index in the MD (longitudinal) direction of the film
TDn: refractive index in the TD (width) direction of the film
ZDn: refractive index in the ZD (thickness) direction of the film Next, a layer containing a propylene-based copolymer (polyolefin-based resin layer (B)) will be described.

  It is important that the propylene-based copolymer constituting the layer (B) has a melting point of 149 to 159 ° C, preferably 151 to 156 ° C. When the melting point is less than 149 ° C., the film surface is roughened in the biaxial stretching step of the film of the present invention, so that the surface smoothness is impaired and the glossiness may be lowered when vapor deposition is performed. On the other hand, if the melting point exceeds 159 ° C., the adhesion with the metallized layer (metal vapor deposition layer) may be reduced. In order to obtain a polypropylene resin having such a melting point, the total amount of propylene is at least one comonomer component selected from α-olefins such as ethylene, butene-1, pentene-1, hexene-1, and 4-methylpentene-1. A method of randomly copolymerizing 0.5 to 4% by mass is preferable, and the copolymerization amount is particularly preferably 2 to 4% by mass. The comonomer is preferably at least one of ethylene and butene-1 because it is excellent in economic efficiency.

  Further, it is important that the plane orientation coefficient (Fn) of the layer (B) (calculated by the formula (1) described in the above layer (A)) is 0.005 to 0.012, preferably 0.008 to 0.011. When the plane orientation coefficient (Fn) exceeds 0.012, the layer (B) is inferior in toughness, and when an impact is applied to the film surface by a cellophane tape peel test or the like, the layer (B) or layer (B) / Cleavage may occur at the interface of layer (A). On the other hand, if Fn is less than 0.005, a whitening phenomenon such as roughening of the surface occurs when metal deposition is performed, and the glossiness of the metal deposition surface may be lowered.

  The plane orientation coefficient (Fn) of the layer (B) can be controlled by the amount of heat applied to the layer (B) in the film stretching step. When the amount of heat applied to the layer (B) is large, the plane orientation coefficient (Fn) of the layer (B) decreases, and when the amount of heat applied to the layer (B) is small, the plane orientation coefficient (Fn) of the layer (B) is decreased. In order to increase the plane orientation coefficient (Fn) of the layer (B) within this range, the temperature condition of the film stretching step may be adjusted as appropriate.

  The layer (B) can contain a known heat stabilizer, antioxidant, chlorine scavenger and the like in order to impart resin stability. As described above, hydrotalcites are preferably used as the chlorine scavenger with little generation of foreign matters. In addition, for the purpose of imparting slipperiness, it is preferable to contain 300 to 1,500 ppm (mass basis) of organic and / or inorganic fillers, and particularly preferably 800 to 1,500 ppm (mass basis). If the total amount of the organic and / or inorganic filler is less than 300 ppm (mass basis), the handling property during production of the film is inferior, and the productivity may be lowered. On the other hand, when the total amount of organic and / or inorganic filler exceeds 1,500 ppm (mass basis), the layer (B) is inferior in toughness due to the large amount of filler, and the surface of the film is subjected to a cellophane tape peel test or the like. When an impact is applied, cleavage may occur in the layer (B).

  Further, for the purpose of imparting film toughness, the layer (B) preferably contains 1 to 10% by mass of a cold xylene soluble part and the mass average molecular weight of the cold xylene soluble part is 10,000 or more. The more preferable range of the content is 2 to 5% by mass. When the cold xylene soluble part is less than 1% by mass, the layer (B) is inferior in toughness, and cleavage occurs in the layer (B) when an impact is applied to the film surface by a cellophane tape peel test or the like. There is a fear. On the other hand, if it exceeds 10% by mass, the film surface may become sticky and blocking may occur. Here, the cold xylene-soluble part is a polypropylene-based component in which a sample such as polypropylene resin is completely dissolved in hot xylene and dissolved in xylene when cooled to room temperature. Further, it is preferable that the cold xylene-soluble part has a small amount of butene-1 in the structure because the compatibility with the crystalline polypropylene component is improved and the toughness is improved. In order to obtain such a structure, a method of adding a high molecular weight atactic polypropylene resin to a propylene-based polymer is preferable. Specifically, a propylene homopolymer, an ethylene-propylene copolymer, a propylene-butene copolymer, An example is a method of adding “Tufselen T3512” (with grade name) made by Sumitomo Chemical to an ethylene propylene butene copolymer or the like.

  Next, it is important that the elemental composition ratio (O / C) of oxygen (O) and carbon (C) on the surface of the layer (B) is 0.2 to 0.4, and more preferably, 0.2. 22-0.39. Further, the presence of nitrogen atoms is also preferable for improving adhesion, and the elemental composition ratio (N / C) of nitrogen (N) to carbon (C) is 0.01 to 0.08. Is more preferable, and 0.02 to 0.06 is more preferable.

  As a result of the bonding of oxygen atoms and / or nitrogen atoms in this way, polar groups such as carbonyl groups, carboxyl groups, amino groups and the like are formed on the surface of the resin layer, and the surface energy increases. When the surface energy is evaluated by a so-called wetting index, the surface of a normal polypropylene film is about 31 mN / m, whereas it is increased to 37 to 56 mN / m, preferably about 40 to 56 mN / m. it can.

  Examples of a method for bonding such oxygen and nitrogen atoms to carbon atoms include corona discharge treatment, plasma treatment, ozone treatment, and the like, and corona treatment is particularly preferable because it is economical. In this case, the corona treatment can be performed in normal air, but it is preferable to treat in an inert gas atmosphere in order to prevent the deterioration of the resin, and the air is replaced with a gas such as nitrogen gas or carbon dioxide gas. It is preferable to process. In particular, when the oxygen concentration in the atmosphere exceeds 5% by volume, the deterioration of the resin due to oxidation is promoted. Further, as a preferable composition of the atmospheric gas, a composition in which nitrogen gas is 80 to 97% by volume and carbon dioxide gas is 3 to 20% by volume is preferable because adhesion to the deposited metal is improved.

  The film of the present invention has at least two layers of the resin layer (A) and the resin layer (B) described above, but the resin layer (B) can be provided on both surfaces of the resin layer (A). Also, a resin layer (C) different from the resin layer (A) and the resin layer (B) may be provided to form a three-layer structure of resin layer (B) / resin layer (A) / resin layer (C). It is possible, and a layer structure can be appropriately selected according to the use. Specifically, when the resin layer (C) is provided, the resin layer (C) is composed of an ethylene propylene butene terpolymer as a heat seal layer, an ethylene propylene block copolymer. The structure etc. which are used as a mat layer are exemplified.

  The resin layer (B) has a function of imparting adhesion to the metal vapor-deposited layer, and it is sufficient if the thickness of the layer (B) is 0.3 μm or more, but considering the uniformity of the lamination, It is preferable that it is 0.5-2 micrometers.

  Further, the thickness of the film of the present invention is not particularly limited because it is appropriately selected depending on the use to be used, but is usually 10 to 100 μm, and in the packaging use, the range of 10 to 25 μm is preferably used. . On the other hand, in the use of a bottle label, a thick film having a thickness of 30 μm or more is preferably used since the waist of the film is required, and a particularly preferable thickness range is 40 to 75 μm.

  Next, the method for producing the film of the present invention will be described below, but the present invention is of course not limited thereto.

  The film of the present invention is preferably biaxially stretched. In the case of a film that has not been biaxially stretched, the film may be inferior in transparency due to the spherulite structure formed at the time of sheet molding, and tends to be inferior in mechanical properties.

  Examples of the biaxial stretching method include a sequential biaxial stretching method based on a flat die method, a simultaneous biaxial stretching method, and a tubular (bubble) method based on a circular die method, but a flat die excellent in film thickness uniformity. The method is preferably used.

  Hereinafter, the manufacturing method by the sequential biaxial stretching method will be described.

  The polypropylene resin (A) for forming the base layer (layer (A)) and the polypropylene resin (B) for forming the layer (B) and imparting adhesion of the metal vapor deposition layer are led to different extruders, respectively. Melt and knead to make a uniform melt. Next, each resin is passed through a polymer filter to remove foreign matters and the like, and then a laminated sheet of resin (A) / resin (B) is formed with a merging device that combines resin (A) and resin (B) into a laminate. Form. These resin (A) and resin (B) constitute the layer (A) and the layer (B) of the film of the present invention as described above. The merging device may be either a method of joining polymer tubes and guiding them to a die to form a sheet, a method of merging with a feed block to form a sheet, or a method of joining with a multi-manifold type die, The multi-manifold type die is preferable because the uniformity of the resin lamination ratio is excellent because the resin is laminated after being widened in the width direction. Of course, in the laminating step, a third or more resins can be prepared to have a layer structure of three or more layers.

  Next, the molten sheet obtained as described above is guided onto a cooling drum, and is brought into close contact with air pressure to be cooled and solidified. By sufficiently cooling at this time, it is possible to reduce the stretching tension during the subsequent stretching and obtain a uniform stretched film. As a cooling method, various cooling means such as a method in which the sheet is brought into close contact with the cooling drum and immediately cooled to the water tank, and a method in which water is sprayed to cool the air-side film surface can be used. . In particular, when the film thickness after biaxial stretching exceeds 50 μm, it is preferable to take cooling means such as water cooling because the uniformity and transparency of the obtained film become good.

  The unstretched sheet obtained by the above method is sequentially brought into contact with a plurality of heated rolls, and after the film temperature is set to 130 to 160 ° C., at least one pair of peripheral speed differences are stretched 3 to 6 times in the longitudinal direction. To do. Next, both ends of the uniaxially stretched film are gripped by clips, guided to a hot air oven, preheated to 150 to 180 ° C., spread between the clips, stretched 7 to 12 times in the width direction, and subsequently 0 in the width direction. Heat fix while allowing 10% relaxation.

  The surface of the biaxially stretched film obtained as described above is subjected to corona discharge treatment, and the clip gripping portion is trimmed and wound up. The corona discharge treatment may be performed in an air atmosphere, but it is preferable to perform the treatment in a nitrogen gas atmosphere or a nitrogen gas / carbon dioxide atmosphere because the adhesion effect is improved.

  The film of the present invention uses the surface of the layer (B) of the film having at least two layers of the above layer (A) / layer (B) as a metal vapor deposition receiving surface.

  In this case, the metal species to be deposited is not particularly limited as long as it can be vaporized or cluster ionized and can be removed in a vacuum, and may be appropriately selected according to the purpose. For example, aluminum, zinc, copper, nickel, chromium, tin, iron, gold, silver and the like are exemplified, and these two or more may be mixed or laminated to be deposited. These metal species may be partially or wholly oxidized when the metal layer is formed on the film surface or after the metal layer is formed. Even when only metal is vapor-deposited, a metal oxide layer is usually formed on both the film surface side and the opposite side of the metal vapor-deposited film. In the film of the present invention, the thickness of the metallized layer (metal vapor deposition layer) formed is preferably 100 to 800 angstroms. When the thickness of the metallized layer is less than 100 angstroms, it is difficult to obtain a sufficient surface gloss. On the other hand, if it exceeds 800 angstroms, the stress between the metallized layer and the film layer increases, which may reduce the adhesion force of vapor deposition and may be disadvantageous in terms of economy. Usually, for the purpose of obtaining sufficient surface glossiness, the film thickness may be 300 to 700 angstroms.

  Moreover, when this invention is used for a packaging use or an industrial use, it is excellent in terms of durability and economy that the metal is aluminum.

  In order to form aluminum on the film surface as a metallized layer, a vacuum vapor deposition technique is generally used in which aluminum is heated and vapor-deposited in a reduced-pressure atmosphere to adhere to the film surface.

  The vacuum deposition method is a batch type deposition method in which a film wound in a roll is placed in a decompression tank for deposition, and the film roll is gradually decompressed while passing between nip rolls installed in multiple stages from the atmosphere. Examples of the continuous vapor deposition method for vapor deposition include the batch vapor deposition method.

In the batch type vapor deposition method, a film to be vapor-deposited in a roll shape is placed in a vacuum vapor deposition apparatus, unwound under a reduced pressure of 10 ⁻² torr or less, and cooled to about −10 to −40 ° C. While being in close contact with the cooling drum, metal vapor is generated from an aluminum evaporation source, adhered on the surface of the film on the cooling drum, and wound on another winding shaft.

  At this time, the thickness of the metallized layer can be controlled by the amount of metal evaporation per unit time, the deposition adhesion efficiency, and the film transport speed. Surface treatment such as glow treatment can be appropriately combined before and after the metal deposition, and other metals and / or metal oxide / silicone compounds can be deposited continuously or mixed.

  As the metal evaporation source, an electric current is passed through a boat made of conductive ceramics and heated, and a wire feed system in which a wire-like metal is continuously fed onto the boat. Alternatively, a method of evaporating the metal itself by induction heating or electron beam is exemplified. Any evaporation source can be selected at any time according to the required quality and cost.

  The film of the present invention thus obtained is used as a label used for bonding to an PET bottle, PP bottle, food can, etc. via an adhesive, used as a cover (protection) used in a photo album, and used as process paper. It can be suitably used for mold release applications. Moreover, since it is excellent in adhesiveness with a metal vapor deposition layer when it carries out metal vapor deposition, and is excellent in an anti-surface cleaving property and an anti-material fracture property, it can use especially suitably for the label use of the bottle which requires metal vapor deposition.

  Hereinafter, embodiments of the film of the present invention will be described based on examples, but the present invention is not limited to these examples.

  The characteristic value measurement method and the effect evaluation method in the present invention are as follows.

(1) Amount of copolymerization of polypropylene resin Examples are as follows.

(Butene-1 copolymerization amount)
The copolymer resin of propylene and butene-1 was analyzed by ¹³ C-NMR method at 140 ° C. to obtain a spectrum. The analysis conditions are as follows.

About 0.3 g of resin sample and about 5 ml of o-dichlorobenzene are charged into a sample tube and dissolved at 140 ° C .; a 10 mmφ probe is used; a measuring device GX-270 (6.34T) manufactured by JEOL Ltd .; ¹³ C observation Frequency 67.94 MHz; Rock solvent benzene-d6; Pulse width 17 μs (90 ° pulse); Integrated repetition time 25 s; Measurement temperature 140 ° C .; Sample rotation speed 15 Hz
<Analysis conditions>
Fourier transform was performed with LB as 5.0, and the methyl carbon peak of polypropylene (PP) was 28.29 ppm, and the methyl carbon peak of polybutene-1 was 34.47 ppm. The area integrated value of each peak was determined using Alice software version 4.8 (manufactured by JEOL Datum). Content of butene-1, using the intensity I _B of methyl carbon peak intensity of PP in the methyl carbon I _PP and butene-1 was determined from the equation below.

PB content _{(mass%) = I B × 56 /} (I PP × 42 + I B × 56) × 100
(2) Melting point (° C)
The measurement was performed under the following conditions using a Seiko RDC220 differential scanning calorimeter.

<Sample preparation>
A sample of 1 to 5 mg is enclosed in an aluminum pan for measurement. In addition, when the metal vapor deposition etc. are given to the film, it removes suitably.

<Measurement>
The film is melted / recrystallized / remelted in the following steps (a) → (b) → (c). The melting point of the resin was defined as the highest melting peak temperature among melting peaks observed at 2nd Run. The average value of n = 3 was obtained.

(A) 1st Run 30 ° C. → 280 ° C. (temperature increase rate 20 ° C./min)
(B) Tmc held at 280 ° C. for 5 minutes and then cooled to 30 ° C. at 20 ° C./min. (C) 2nd Run 30 ° C. → 280 ° C. (temperature increase rate 20 ° C./min)
(3) Melt flow index (MFR (g / 10 min))
Melt flow rate of polypropylene resin at 230 ° C. Measurement was performed according to a polypropylene test method (230 ° C., 21.18 N) and a polyethylene test method (190 ° C., 21.18 N) shown in JIS K-7210 (1999).

(4) Ratio of oxygen atoms to carbon atoms on the film surface (O / C), and ratio of nitrogen atoms (N / C)
The film surface was measured under the following conditions using ESCA spectrometer model ES200 manufactured by Kokusai Electric Co., Ltd. Excitation X-ray: Al Kα ray (1486.6 eV), X-ray output: 10 Kv 20 mA, temperature: 20 ° C., kinetic energy correction: the kinetic energy of neutral carbon (—CH ₂ —) was adjusted to 1202.0 eV. From the obtained energy value, the ratio of the peak area of C1s and the peak area of O1s was O / C, and the ratio of the peak areas of C1s and N1s was N / C.

(5) Wetting index (wetting tension)
It measured according to JIS K-6768 (1999).

(6) Thickness constitution of film and thickness of metal vapor deposition layer The cross section of the film was photographed with a transmission electron microscope (TEM) under the following conditions, and the thickness constitution of the film and the thickness of the metal vapor deposition layer were measured. Apparatus: JEM-1200EX manufactured by JEOL Ltd., Observation magnification: 1,000 times for film thickness configuration, 400,000 times for metal deposition layer thickness, acceleration voltage: 100 kV
(7) Gloss (Glossiness)
According to JIS K-7105 (1981), the average value of five data measured under the conditions of an incident angle of 60 ° and a light receiving angle of 60 ° using a digital variable angle gloss meter UGV-5D manufactured by Suga Test Instruments Co., Ltd. It was. The gloss of the vapor deposition surface is desirably 400% or more.

(8) Vapor deposition adhesion strength Sample of metal aluminum deposited on the film surface (layer (B) side) so that its thickness is 500 ± 50 angstroms (optical density (OD) conversion 2 ± 0.2) It was. Nitto Denko Co., Ltd. polyester adhesive tape NO. 31B was applied at a pressure of 4.2 mN / mm ² and peeled off.

  The area in which the metal remained attached to the film was determined, and the following five grades were evaluated.

  If it is 4th grade or higher, it can be used without problems, but if it is 2nd grade or lower, practical problems arise.

Grade 5: Residual area 90% or more Grade 4: Residual area 75% or more and less than 90% Grade 3: Residual area 50% or more and less than 75% Grade 2: Residual area 25% or more and less than 50% Grade 1: Residual area less than 25% ( 9) Surface toughness The state of the film sample obtained by the same method as the above-mentioned (8) vapor deposition adhesion was determined according to the following criteria.

      ○: The surface was not cleaved.

      Δ: A part of the film has a surface cleaved portion.

      X: The surface is completely cleaved over the entire surface of the film.

(10) Plane orientation coefficient The plane orientation coefficient was measured using an Abbe refractometer using sodium D line (wavelength 589 nm) as a light source. The plane orientation coefficient Fn = (MDn + TDn) / 2−ZDn obtained from the refractive indexes (MDn, TDn, ZDn) in the longitudinal direction, the width direction, and the thickness direction was obtained by calculation. For the measurement, a methyl salicylate solution was used as the mount solution, and the plane orientation coefficients of the layers (B) and (C) were determined. Further, the plane orientation coefficient of the layer (A) was measured in the same manner by peeling off the layer (B) with a razor to expose the surface of the layer (A).

(11) Cold xylene soluble part (CXS value)
After dissolving 0.5 g of a polypropylene film sample in 100 ml of boiling xylene and allowing to cool, 2
The polypropylene component dissolved in the filtrate after recrystallization in a constant temperature water bath at 0 ° C. for 1 hour is quantified by liquid chromatography (X (g)).

  Using the precision value (X0 (g)) of 0.5 g of the sample, the following formula is used.

CXS value (mass%) = (X / X0) × 100
(12) Mass average molecular weight It calculated | required on the basis of monodisperse polystyrene using the gel permeation chromatography (GPC).

  The mass average molecular weight (Mw) is defined by the following equation by the number of molecules (Ni) of the molecular weight (Mi) at each elution position of the GPC curve obtained through the molecular weight calibration curve.

Mass average molecular weight: Mw = Σ (Ni · Mi ² ) / Σ (Ni · Mi)
The measurement conditions were as follows (<> indicates manufacturer).

Apparatus: Gel permeation chromatograph GPC-150C <Waters>
Detector: Differential refractive index detector RI sensitivity 32 ×, 20% <Waters>
Column: Shodex HT-806M (2) <Showa Denko>
Solvent: 1,2,4-trichlorobenzene (BHT 0.1 w / v% added) <Aldrich>
Flow rate: 1.0 ml / min
Temperature: 135 ° C
Sample: Dissolution condition 165 ± 5 ° C. × 10 minutes (stirring)
Concentration 0.20w / v%
Filtration Membrane filter pore size 0.45μm <Showa Denko>
Injection volume: 200 μl
Molecular weight calibration: The molecular weight of polypropylene was determined using the relationship between molecular weight and retention time obtained by measuring monodisperse polystyrene (Tosoh) under the same conditions as the specimen. Data processing which is a relative value based on polystyrene: According to a GPC data processing system manufactured by Toray Research Center.

(13) Film Formation Method As a film layer structure, a film made of three polypropylene resin layers is formed and the characteristics are evaluated.

  Resins a1 and a2 shown in Table 1 were prepared as the layer (A), resins b1 to b9 shown in Table 1 were prepared as the layer (B), and a resin c shown in Table 1 was prepared as the layer (C).

  When butene-1 or ethylene was polymerized, the butene-1 or ethylene monomer was introduced into the first reactor and polymerized and dispersed in polypropylene.

  In addition, “silton” JC-20 (silica particles) manufactured by Mizusawa Chemical Industry Co., Ltd. was added as an antiblocking agent for b1 to b9 and c so as to have a predetermined content.

  Moreover, about the said b1-b9, c, the Sumitomo Chemical Co., Ltd. product "Tough selenium" was kneaded as a non-crystalline polypropylene so that it might become predetermined | prescribed content with a biaxial kneader.

  Each of these resins was melt-extruded using three single-screw extruders (barrel diameter 65 mmφ: Ex1, 30 mmφ: Ex2, 30 mmφ: Ex3), and three layers of layer (B) / layer (A) / layer (C) A resin sheet consisting of the above is introduced into a multi-manifold die that can be formed and extruded into a sheet shape. The molten sheet discharged from the die is brought into close contact with a cooling drum set at 25 ° C. with air pressure, and further, substantially half of the cooling drum is submerged in the water tank, and the molten sheet is guided into the water tank while being pressed against the cooling drum with air pressure. Cooling. Cooling water is circulated so that the water temperature of the water tank is maintained at 25 ° C. Subsequently, the sheet was preheated to a predetermined temperature with a group of six heating rolls and then stretched in the longitudinal direction at a predetermined magnification between rolls provided with a pair of peripheral speed differences. Next, the stretched film was gripped with a clip, guided to a hot air oven, preheated to a predetermined temperature, stretched at a predetermined magnification in the width direction, and heat-fixed with 5% relaxation. The biaxially stretched film thus obtained was subjected to corona discharge treatment in air, the edges were removed, and the film was wound into a roll. The conditions for the corona discharge treatment were set as follows.

Atmosphere: 90% by volume of nitrogen gas + 10% by volume of carbon dioxide gas
Film temperature: 60 ° C
Processing intensity: 23 W / m ² / min
The biaxially stretched polypropylene film thus obtained was subjected to characteristic evaluation by depositing metallic aluminum with a crucible type vapor deposition device so that the film thickness was ± 50 angstroms with a central value of 500 angstroms.

  Hereinafter, the present invention will be described based on implementation and comparative examples.

(Example 1)
Biaxial, using resin b1 as the resin on the deposition surface side (layer (B)), resin a1 as the core layer (layer (A)), and resin c as the surface layer (layer (C)) opposite to the deposition surface The films were laminated such that the film thickness after stretching was 1: 48: 1 μm (total thickness was 50 μm). The film forming method was preheated to 140 ° C. in the longitudinal direction and stretched 4.8 times according to the above method, and further preheated to 160 ° C. in the transverse direction and stretched 9 times. Thereafter, the surface of the layer (B) was subjected to corona discharge treatment in an air atmosphere and wound up. The (B / C) surface (O / C) of the obtained biaxially oriented polypropylene film was 0.23, and the plane orientation coefficients of the layers (A), (B), and (C) were 0.009 and 0.015, respectively. 0.011, the adhesion strength when metal was deposited was grade 4, and the surface glossiness was 550%.

  The biaxially oriented polypropylene film thus obtained was excellent in metal vapor deposition adhesive force, and had good vapor deposition appearance and surface toughness.

(Example 2)
Biaxially using resin b2 as the resin on the deposition surface side (layer (B)), resin a1 as the core layer (layer (A)), and resin c as the surface layer (layer (C)) opposite to the deposition surface The films were laminated such that the film thickness after stretching was 1: 48: 1 μm (total thickness was 50 μm). The film forming method was preheated to 140 ° C. in the longitudinal direction and stretched 4.8 times according to the above method, and further preheated to 160 ° C. in the transverse direction and stretched 9 times. In addition, the input power conditions for performing the corona discharge treatment on the surface of the layer (B) were the same as those in Example 1, and the atmosphere was set so that the ratio of nitrogen gas: carbon dioxide gas was 9: 1 by volume ratio. (O / C) on the surface of the layer (B) of the obtained biaxially oriented polypropylene film is 0.25, (N / C) is 0.04, and the plane orientation of the layers (A), (B), (C) The coefficients were 0.010, 0.015, and 0.011, respectively. The adhesion strength when metal was deposited was grade 5, and the surface glossiness was 570%.

  The biaxially oriented polypropylene film thus obtained was extremely excellent in metal vapor deposition adhesion, and had good vapor deposition appearance and surface toughness.

(Example 3)
Biaxially using resin b2 as the resin on the deposition surface side (layer (B)), resin a2 as the core layer (layer (A)), and resin c as the surface layer (layer (C)) opposite to the deposition surface The films were laminated such that the film thickness after stretching was 1: 48: 1 μm (total thickness was 50 μm). The film forming method was preheated to 140 ° C. in the longitudinal direction and stretched 4.8 times according to the above method, and further preheated to 160 ° C. in the transverse direction and stretched 9 times. Thereafter, the surface of the layer (B) was subjected to corona discharge treatment in an air atmosphere and wound up. The (B / C) surface (O / C) of the resulting biaxially oriented polypropylene film was 0.23, and the plane orientation coefficients of the layers (A), (B), and (C) were 0.010 and 0.015, respectively. 0.011, the adhesion strength when metal was deposited was grade 4, and the surface glossiness was 570%.

  The biaxially oriented polypropylene film thus obtained was excellent in metal vapor deposition adhesive force, and had good vapor deposition appearance and surface toughness.

Example 4
Biaxially using resin b3 as the resin on the deposition surface side (layer (B)), resin a1 as the core layer (layer (A)), and resin c as the surface layer (layer (C)) opposite to the deposition surface The films were laminated such that the film thickness after stretching was 1: 48: 1 μm (total thickness was 50 μm). The film forming method was preheated to 140 ° C. in the longitudinal direction and stretched 4.8 times according to the above method, and further preheated to 160 ° C. in the transverse direction and stretched 9 times. Thereafter, the surface of the layer (B) was subjected to corona discharge treatment in an air atmosphere and wound up. The (B / C) surface (O / C) of the resulting biaxially oriented polypropylene film was 0.23, and the plane orientation coefficients of the layers (A), (B), and (C) were 0.010 and 0.015, respectively. 0.011, the adhesion strength when metal was deposited was grade 4, and the surface glossiness was 485%.

  The biaxially oriented polypropylene film thus obtained was excellent in metal vapor deposition adhesive force, and had good vapor deposition appearance and surface toughness.

(Example 5)
Biaxially using resin b4 as the resin on the vapor deposition surface side (layer (B)), resin a1 as the core layer (layer (A)), and resin c as the surface layer (layer (C)) opposite to the vapor deposition surface The films were laminated such that the film thickness after stretching was 1: 48: 1 μm (total thickness was 50 μm). The film forming method was preheated to 140 ° C. in the longitudinal direction and stretched 4.8 times according to the above method, and further preheated to 160 ° C. in the transverse direction and stretched 9 times. Thereafter, the surface of the layer (B) was subjected to corona discharge treatment in an air atmosphere and wound up. The (B / C) surface (O / C) of the obtained biaxially oriented polypropylene film was 0.23, and the plane orientation coefficients of the layers (A), (B), and (C) were 0.008 and 0.015, respectively. 0.011. The adhesion strength when metal was deposited was grade 5, and the surface glossiness was 400%.

  The biaxially oriented polypropylene film obtained in this way was slightly inferior in vapor deposition appearance, but was excellent in metal vapor deposition adhesion and good in surface toughness.

(Example 6)
Biaxially using resin b5 as the resin on the deposition surface side (layer (B)), resin a1 as the core layer (layer (A)), and resin c as the surface layer (layer (C)) opposite to the deposition surface The films were laminated such that the film thickness after stretching was 1: 48: 1 μm (total thickness was 50 μm). The film forming method was preheated to 140 ° C. in the longitudinal direction and stretched 4.8 times according to the above method, and further preheated to 160 ° C. in the transverse direction and stretched 9 times. Thereafter, the surface of the layer (B) was subjected to corona discharge treatment in an air atmosphere and wound up. The (B / C) surface (O / C) of the resulting biaxially oriented polypropylene film was 0.23, and the plane orientation coefficients of the layers (A), (B), and (C) were 0.011 and 0.015, respectively. , 0.011, the adhesion when the metal was deposited was grade 3, and the surface glossiness was 580%.

  Although the biaxially oriented polypropylene film thus obtained was slightly inferior to the metal vapor deposition adhesive force, the vapor deposition appearance and surface toughness were also good.

(Example 7)
Biaxial, using resin b1 as the resin on the deposition surface side (layer (B)), resin a1 as the core layer (layer (A)), and resin c as the surface layer (layer (C)) opposite to the deposition surface The films were laminated such that the film thickness after stretching was 1: 48: 1 μm (total thickness was 50 μm). The film forming method was preheated to 140 ° C. in the longitudinal direction and stretched 4.8 times according to the above method, and further preheated to 160 ° C. in the transverse direction and stretched 9 times. In addition, the atmosphere when performing the corona discharge treatment on the surface of the layer (B) is set in the same manner as in Example 1 so that the processing power is 0.9 times that in Example 1, and the surface of the layer (B) is air. It was wound up after corona discharge treatment in an atmosphere. The (O / C) on the surface of the layer (B) of the obtained biaxially stretched polypropylene film is 0.2, and the plane orientation coefficients of the layers (A), (B), and (C) are 0.009 and 0.015, respectively. , 0.011, the adhesion when the metal was deposited was grade 3, and the surface gloss was 550%.

  Although the biaxially oriented polypropylene film thus obtained was slightly inferior to the metal vapor deposition adhesive force, the vapor deposition appearance and surface toughness were also good.

(Example 8)
Biaxial, using resin b1 as the resin on the deposition surface side (layer (B)), resin a1 as the core layer (layer (A)), and resin c as the surface layer (layer (C)) opposite to the deposition surface The films were laminated such that the film thickness after stretching was 1: 48: 1 μm (total thickness was 50 μm). In accordance with the method described above, the film was formed by preheating to 142 ° C. in the longitudinal direction and then stretching 4.8 times, and further preheating to 162 ° C. in the transverse direction and stretching 9 times. Thereafter, the surface of the layer (B) was subjected to corona discharge treatment in an air atmosphere and wound up. The (B / C) surface (O / C) of the obtained biaxially oriented polypropylene film was 0.23, and the plane orientation coefficients of the layers (A), (B), and (C) were 0.008 and 0.013, respectively. 0.009, the adhesion when the metal was deposited was grade 4, and the surface glossiness was 480%.

  The biaxially oriented polypropylene film obtained in this manner had a portion that generates heat wrinkles during vapor deposition, and although it was somewhat inferior in vapor deposition workability and vapor deposition appearance, it was excellent in metal vapor deposition adhesion and had good surface toughness.

Example 9
Biaxial, using resin b1 as the resin on the deposition surface side (layer (B)), resin a1 as the core layer (layer (A)), and resin c as the surface layer (layer (C)) opposite to the deposition surface The films were laminated such that the film thickness after stretching was 1: 48: 1 μm (total thickness was 50 μm). In accordance with the above-mentioned method, the film-forming method was preheated to 138 ° C. in the longitudinal direction and then stretched 4.8 times, and further preheated to 158 ° C. in the transverse direction and stretched 9 times. Thereafter, the surface of the layer (B) was subjected to corona discharge treatment in an air atmosphere and wound up. The (B / C) surface (O / C) of the obtained biaxially oriented polypropylene film (B) is 0.23, and the plane orientation coefficients of the layers (A), (B), and (C) are 0.012 and 0.017, respectively. 0.013, adhesion strength when metal was deposited was grade 4, and surface glossiness was 510%.

  The biaxially oriented polypropylene film obtained in this way was slightly inferior in surface toughness, but was excellent in metal vapor deposition adhesion and good in vapor deposition appearance.

(Example 10)
Biaxially using resin b6 as the resin on the deposition surface side (layer (B)), resin a1 as the core layer (layer (A)), and resin c as the surface layer (layer (C)) on the opposite side to the deposition surface The films were laminated such that the film thickness after stretching was 1: 48: 1 μm (total thickness was 50 μm). The film forming method was preheated to 140 ° C. in the longitudinal direction and stretched 4.8 times according to the above method, and further preheated to 160 ° C. in the transverse direction and stretched 9 times. Thereafter, the surface of the layer (B) was subjected to corona discharge treatment in an air atmosphere and wound up. The (B / C) surface (O / C) of the resulting biaxially oriented polypropylene film was 0.23, and the plane orientation coefficients of the layers (A), (B), and (C) were 0.010 and 0.015, respectively. 0.011, the adhesion strength when metal was deposited was grade 4, and the surface glossiness was 580%.

  Although the biaxially oriented polypropylene film thus obtained was slightly inferior in handling at the time of production, it was excellent in adhesion to metal vapor deposition and had very good vapor deposition appearance and surface toughness.

Example 11
Biaxially using resin b7 as the resin on the vapor deposition surface side (layer (B)), resin a1 as the core layer (layer (A)), and resin c as the surface layer (layer (C)) opposite to the vapor deposition surface The films were laminated such that the film thickness after stretching was 1: 48: 1 μm (total thickness was 50 μm). The film forming method was preheated to 140 ° C. in the longitudinal direction and stretched 4.8 times according to the above method, and further preheated to 160 ° C. in the transverse direction and stretched 9 times. Thereafter, the surface of the layer (B) was subjected to corona discharge treatment in an air atmosphere and wound up. The (B / C) surface (O / C) of the resulting biaxially oriented polypropylene film was 0.23, and the plane orientation coefficients of the layers (A), (B), and (C) were 0.010 and 0.015, respectively. , 0.011, the adhesion when the metal was deposited was grade 4, and the surface glossiness was 530%.

  The biaxially oriented polypropylene film obtained in this way was slightly inferior in surface toughness, but was excellent in metal vapor deposition adhesion and good in vapor deposition appearance.

Example 12
Biaxially using resin b8 as the resin on the deposition surface side (layer (B)), resin a1 as the core layer (layer (A)), and resin c as the surface layer (layer (C)) on the side opposite to the deposition surface The films were laminated such that the film thickness after stretching was 1: 48: 1 μm (total thickness was 50 μm). The film forming method was preheated to 140 ° C. in the longitudinal direction and stretched 4.8 times according to the above method, and further preheated to 160 ° C. in the transverse direction and stretched 9 times. Thereafter, the surface of the layer (B) was subjected to corona discharge treatment in an air atmosphere and wound up. The (B / C) surface (O / C) of the resulting biaxially oriented polypropylene film was 0.23, and the plane orientation coefficients of the layers (A), (B), and (C) were 0.010 and 0.015, respectively. , 0.011, the adhesion strength when metal was deposited was grade 4, and the surface glossiness was 560%.

  The biaxially oriented polypropylene film obtained in this way was slightly inferior in surface toughness, but was excellent in metal vapor deposition adhesion and good in vapor deposition appearance.

(Comparative Example 1)
Biaxially using resin b9 as the resin on the deposition surface side (layer (B)), resin a1 as the core layer (layer (A)), and resin c as the surface layer (layer (C)) opposite to the deposition surface The films were laminated such that the film thickness after stretching was 1: 48: 1 μm (total thickness was 50 μm). The film forming method was preheated to 140 ° C. in the longitudinal direction and stretched 4.8 times according to the above method, and further preheated to 160 ° C. in the transverse direction and stretched 9 times. Thereafter, the surface of the layer (B) was subjected to corona discharge treatment in an air atmosphere and wound up. The (B / C) surface (O / C) of the obtained biaxially oriented polypropylene film was 0.23, and the plane orientation coefficients of the layers (A), (B), and (C) were 0.007 and 0.015, respectively. , 0.011, the adhesion when metal was deposited was grade 5, and the surface gloss was 340%.

  The biaxially oriented polypropylene film thus obtained was extremely excellent in metal vapor deposition adhesive force and surface toughness, but had a low surface glossiness and poor vapor deposition appearance, and could not withstand practical use.

(Comparative Example 2)
Biaxially using resin c as the resin on the deposition surface side (layer (B)), resin a1 as the core layer (layer (A)), and resin c as the surface layer (layer (C)) opposite to the deposition surface The films were laminated such that the film thickness after stretching was 1: 48: 1 μm (total thickness was 50 μm). The film forming method was preheated to 140 ° C. in the longitudinal direction and stretched 4.8 times according to the above method, and further preheated to 160 ° C. in the transverse direction and stretched 9 times. Thereafter, the surface of the layer (B) was subjected to corona discharge treatment in an air atmosphere and wound up. The (B / C) surface (O / C) of the resulting biaxially oriented polypropylene film was 0.23, and the plane orientation coefficients of the layers (A), (B), and (C) were 0.011 and 0.015, respectively. 0.011, the adhesion strength when metal was deposited was second grade, and the surface glossiness was 550%.

  The biaxially oriented polypropylene film thus obtained had good vapor deposition appearance and surface toughness, but was inferior in metal vapor deposition adhesion and could not withstand practical use.

(Comparative Example 3)
Biaxially using resin b2 as the resin on the deposition surface side (layer (B)), resin a1 as the core layer (layer (A)), and resin c as the surface layer (layer (C)) opposite to the deposition surface The films were laminated such that the film thickness after stretching was 1: 48: 1 μm (total thickness was 50 μm). The film forming method was preheated to 140 ° C. in the longitudinal direction and stretched 4.8 times according to the above method, and further preheated to 160 ° C. in the transverse direction and stretched 9 times.

  The atmosphere when the corona discharge treatment is performed on the surface of the layer (B) is set in the same manner as in Example 1 so that the treatment power is 0.5 times that in Example 1, and the surface of the layer (B) is air. It was wound up after corona discharge treatment in an atmosphere. Thereafter, the surface of the layer (B) was subjected to corona discharge treatment in an air atmosphere and wound up. The (O / C) on the surface of the layer (B) of the obtained biaxially oriented polypropylene film is 0.10, and the plane orientation coefficients of the layers (A), (B), and (C) are 0.010 and 0.015, respectively. 0.011, the adhesion strength when metal was deposited was first grade, and the surface glossiness was 540%.

  The biaxially oriented polypropylene film thus obtained had good vapor deposition appearance and surface toughness, but was inferior in metal vapor deposition adhesion and could not withstand practical use.

(Comparative Example 4)
Biaxial, using resin b1 as the resin on the deposition surface side (layer (B)), resin a1 as the core layer (layer (A)), and resin c as the surface layer (layer (C)) opposite to the deposition surface The films were laminated such that the film thickness after stretching was 1: 48: 1 μm (total thickness was 50 μm). In accordance with the above-mentioned method, the film-forming method was preheated to 145 ° C in the longitudinal direction and then stretched 4.8 times, and further preheated to 165 ° C in the transverse direction and stretched 9 times. Thereafter, the surface of the layer (B) was subjected to corona discharge treatment in an air atmosphere and wound up. The (B / C) surface (O / C) of the obtained biaxially stretched polypropylene film was 0.23, and the plane orientation coefficients of the layers (A), (B), and (C) were 0.007 and 0.012, respectively. 0.008, adhesion when the metal was deposited was grade 4, and the surface gloss was 380%.

  The biaxially oriented polypropylene film thus obtained has excellent metal vapor deposition adhesiveness and surface toughness, but has heat wrinkles during vapor deposition and poor vapor deposition processability, and has a low surface glossiness and a vapor deposition appearance. It was inferior and could not stand practical use.

(Comparative Example 5)
Biaxial, using resin b1 as the resin on the deposition surface side (layer (B)), resin a1 as the core layer (layer (A)), and resin c as the surface layer (layer (C)) opposite to the deposition surface The films were laminated such that the film thickness after stretching was 1: 48: 1 μm (total thickness was 50 μm). In accordance with the above-mentioned method, the film-forming method was preheated to 135 ° C. in the longitudinal direction and then stretched 4.8 times, and further preheated to 155 ° C. in the transverse direction and stretched 9 times. Thereafter, the surface of the layer (B) was subjected to corona discharge treatment in an air atmosphere and wound up. The (O / C) on the surface of the layer (B) of the obtained biaxially oriented polypropylene film was 0.23, and the plane orientation coefficients of the layers (A), (B), and (C) were 0.014 and 0.0220, respectively. .015.

  The biaxially oriented polypropylene film thus obtained had poor thickness uniformity due to stretching unevenness, and uneven thickness was produced everywhere, so that it was not practical.

Claims (5)

It has at least two layers of a polypropylene resin layer (A) and a polyolefin resin layer (B) containing a propylene copolymer having a melting point of 149 to 159 ° C., and oxygen on the surface of the polyolefin resin layer (B) The elemental composition ratio (O / C) of (O) and carbon (C) is 0.2 to 0.4, and the plane orientation coefficient (Fn) represented by the following formula (1) is a polypropylene resin layer (A). Metal film for metal vapor deposition of 0.013-0.020 in the polyolefin resin layer (B).
Fn = (MDn + TDn) / 2−ZDn (1)
MDn: refractive index in the MD (longitudinal) direction of the film
TDn: refractive index in the TD (width) direction of the film
ZDn: refractive index in the ZD (thickness) direction of the film The polypropylene film for metal vapor deposition of Claim 1 whose total amount of the organic and / or inorganic filler contained in a polyolefin resin layer (B) is 300-1,500 ppm (mass basis). The metal according to claim 1 or 2, wherein the polyolefin resin layer (B) contains 1 to 10% by mass of a cold xylene soluble part, and the mass average molecular weight of the cold xylene soluble part is 10,000 or more. Polypropylene film for vapor deposition. The polypropylene film for metal vapor deposition according to any one of claims 1 to 3, wherein the thickness is 40 to 75 µm. A metal having a metal vapor deposition layer provided on the surface of the polyolefin resin layer (B) of the polypropylene film for metal vapor deposition according to any one of claims 1 to 4, wherein the metal vapor deposition layer has a thickness of 100 to 800 angstroms. Polypropylene film.