JP2008208210A - Polypropylene film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polypropylene film excellent in slip characteristics, scratch resistance, block resistance, dispersibility, FE characteristics and yellowing resistance over a long period of time and having a good transparency. <P>SOLUTION: This polypropylene film is obtained by blending 0.01 to 0.5 pt.wt. spherical synthetic silica particles having 1 to 6 μm mean particle diameter, 50 to 250 m<SP>2</SP>/g specific surface area by BET method, ≤1 ml/g pore volume and ≤150 ml/100 g amount of an oil absorption based on 100 pts.wt. propylene-based polymer consisting of a propylene homopolymer or a propylene/α-olefin copolymer. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a polypropylene film, and in particular, is excellent in slip resistance, scratch resistance, blocking resistance, dispersibility, fish eye characteristics (hereinafter also referred to as FE characteristics) and long-term yellowing resistance, and has good transparency. It relates to a polypropylene film.

  In recent years, the required performance of polypropylene films has been increasing, and in particular, slip and blocking resistance are indispensable properties during film molding and secondary processing. A blocking agent is used as a suitable compounding agent. As an anti-blocking agent, silicon dioxide such as synthetic silica is relatively soft and often used because the film surface is not easily damaged by rubbing between films. For example, it contains specific porous spherical silica or silicate particles. The compounding agent composition for resin formed is proposed (for example, refer patent document 1).

  However, this compounding composition for resin is excellent in dispersibility, rapid efficacy and sustainability in the resin and hardly damages the film surface, but the porous spherical silica or silicate particles in the composition are When blending with a stirrer together with a resin, the particles tend to disintegrate, the particles become small, and further they cause secondary agglomeration, so that fish eyes (hereinafter also referred to as FE) are easily generated and the product value is lowered. Have the problem.

In addition, yellowing resistance and scratch resistance (scratch resistance) are also important for the film.
If the film is yellowed, even if it is not noticeable yellow as the film, the yellowness increases over time, and when the film is wound, the end face of the roll appears yellow, so the aesthetics of the product itself can be improved. You will lose.
If the film is easily damaged, the film surface may be damaged during secondary processing or transportation of the film, causing a reduction in product value. In particular, scratch resistance is the most important for vapor deposition film applications. For example, in the case of a film that has been vapor-deposited into a mirror surface, scratches on the surface are more conspicuous than a film that has not been vapor-deposited, and slight scratches reduce the product value. It is a factor to make.

  Therefore, various propylene-based metal vapor deposition films containing an antiblocking agent (hereinafter sometimes referred to as AB agent) have been proposed (see, for example, Patent Documents 2 to 5). However, these are also sufficient in terms of the highly required properties for films that are excellent in slip resistance, scratch resistance, blocking resistance, dispersibility, FE characteristics and long-term yellowing resistance, and have good transparency. is not.

JP-A-8-81584 JP-A-6-212404 Japanese Patent Laid-Open No. 8-104977 JP 2003-176389 A Japanese Patent Laid-Open No. 2004-17584

  The subject of the present invention is excellent in slip property, scratch resistance, blocking resistance, dispersibility, FE characteristics and long-term yellowing resistance, and transparency in order to meet the high performance required for the polypropylene film. The object is to provide a good polypropylene film.

  As a result of intensive studies to solve the above problems, the present inventors have found that a film obtained from a resin composition obtained by blending a propylene-based polymer with spherical synthetic silica having specific physical properties at a specific ratio is suitable. Based on this finding, the present inventors have made the present invention.

That is, according to 1st invention of this invention, with respect to 100 weight part of propylene-type polymers which consist of a propylene homopolymer or a propylene-alpha-olefin copolymer, an average particle diameter of 1-6 micrometers, the specific surface area by BET method in There 50 to 250 m ² / g, obtained from the pore volume of 1 ml / g or less and oil absorption by blending 0.01 to 0.5 parts by weight or less of spherical synthetic silica 150 ml / 100 g resin composition A polypropylene film is provided.

  According to a second aspect of the present invention, there is provided a polypropylene film characterized in that, in the first aspect, the propylene-based polymer is polymerized using a metallocene catalyst.

  According to the third invention of the present invention, in the first or second invention, the resin composition further comprises 0.05 to 0.5 parts by weight of a lubricant with respect to 100 parts by weight of the propylene polymer. A polypropylene film is provided.

  Moreover, according to the 4th invention of this invention, the metal vapor deposition film characterized by using the polypropylene film in any one of the 1st-3rd invention is provided.

According to the polypropylene film of the present invention, a remarkable effect is exhibited in that it is excellent in slip resistance, scratch resistance, blocking resistance, dispersibility, FE characteristics and yellowing resistance over a long period of time, and has good transparency.
Therefore, the polypropylene film of the present invention is usually excellent in the properties required for the film, in particular, aesthetics, and is particularly suitable as a metal vapor deposition film that is easily affected by scratches.

  The polypropylene film of this invention is obtained from the resin composition which mix | blended 0.01-0.5 weight part of spherical synthetic silica which has a specific physical property with respect to 100 weight part of propylene-type polymers.

<Propylene polymer>
Examples of the propylene polymer used in the present invention include a propylene homopolymer and / or a propylene-α-olefin copolymer.
As the propylene-α-olefin copolymer, an α-olefin having 2 to 8 carbon atoms excluding propylene is used as a comonomer, preferably propylene content of 80% by weight or more, especially 90% by weight or more of propylene and α-olefin The copolymer may be a random copolymer, a block copolymer, a mixture thereof, or a polymer obtained by sequential polymerization. . Moreover, the comonomer which is a C2-C8 alpha olefin except the propylene copolymerized with a propylene may be used 1 type, and may be used in combination of 2 or more type. As the propylene-α-olefin copolymer, a propylene-ethylene random copolymer or a propylene-ethylene-butene-1 terpolymer is particularly preferable.

  Examples of the α-olefin having 2 to 8 carbon atoms excluding propylene include ethylene, 1-butene, 2-methyl-1-propene, 1-pentene, 2-methyl-1-butene and 3-methyl-1-butene. 1-hexene, 2-ethyl-1-butene, 2,3-dimethyl-1-butene, 2-methyl-1-pentene, 3-methyl-1-pentene, 4-methyl-1-pentene, 3,3 -Dimethyl-1-butene, 1-heptene, methyl-1-hexene, dimethyl-1-pentene, ethyl-1-pentene, trimethyl-1-butene, 1-octene and the like can be mentioned.

  The propylene polymer used in the present invention is not particularly limited with respect to the melt flow rate (MFR: temperature 230 ° C., load 21.18 N), but is preferably 3 to 15 g / 10 min.

  Such a propylene polymer can be produced by a conventionally known production method. The catalyst used in the production is not particularly limited, but a metallocene catalyst called a Kaminsky catalyst gives excellent blocking resistance to a film obtained from the produced propylene polymer. In addition, a catalyst system including a titanium-containing solid catalyst component and an organoaluminum compound as a cocatalyst component is preferable. The titanium-containing solid catalyst component is a known carrier-supported catalyst component obtained by contacting a solid magnesium compound, titanium tetrahalide and an electron donating compound, or a known catalyst component containing titanium trichloride or titanium trichloride as a main component. Chosen from. Further, in addition to the solid catalyst component and the cocatalyst component, a catalyst system using a known electron donating compound as the third component may be used.

  The metallocene catalyst is (i) a transition metal compound of Group 4 of the periodic table (so-called metallocene compound) containing a ligand having a cyclopentadienyl skeleton, and (ii) a stable ionic state by reacting with the metallocene compound. It is a catalyst comprising a cocatalyst that can be activated and (iii) an organoaluminum compound, which is appropriately used as necessary, and any known catalyst can be used. As the metallocene compound, preferably a bridged metallocene compound capable of stereoregular polymerization of propylene, more preferably a bridged metallocene compound capable of isoregular polymerization of propylene is used. Hereinafter, each component (i)-(iii) is demonstrated.

  (I) The metallocene compounds include, for example, JP-A-60-35007, JP-A-63-130314, JP-A-63-295607, JP-A-1-275609, JP-A-2-41303, and JP-A-2 -131488, JP-A-2-76887, JP-A-3-163088, JP-A-4-300877, JP-A-4-21694, JP-A-5-43616, JP-A-5-209903, JP-A-6- 6903 No. 239914, JP-A-7-504934, and JP-A-8-85708.

Specific examples of the metallocene compound include methylenebis (2-methylindenyl) zirconium dichloride, ethylenebis (2-methylindenyl) zirconium dichloride, ethylene 1,2- (4-phenylindenyl) (2-methyl-4 -Phenyl-4H-azulenyl) zirconium dichloride, isopropylidene (cyclopentadienyl) (fluorenyl) zirconium dichloride, isopropylidene (4-methylcyclopentadienyl) (3-t-butylindenyl) zirconium dichloride, dimethylsilylene ( 2-methyl-4-t-butyl-cyclopentadienyl) (3′-t-butyl-5′-methyl-cyclopentadienyl) zirconium dichloride, dimethylsilylenebis (indenyl) zirconium dichloride, dimethylsilane Renbis (4,5,6,7-tetrahydroindenyl) zirconium dichloride, dimethylsilylenebis [1- (2-methyl-4-phenylindenyl)] zirconium dichloride, dimethylsilylenebis [1- (2-ethyl-4) -Phenylindenyl)] zirconium dichloride, dimethylsilylenebis [4- (1-phenyl-3-methylindenyl)] zirconium dichloride, dimethylsilylene (fluorenyl) t-butylamidozirconium dichloride, methylphenylsilylenebis [1- ( 2-methyl-4, (1-naphthyl) -indenyl)] zirconium dichloride, dimethylsilylenebis [1- (2-methyl-4,5-benzoindenyl)] zirconium dichloride, dimethylsilylenebis [1- (2- Methyl-4-phenyl -4H-azulenyl)] zirconium dichloride, dimethylsilylenebis [1- (2-ethyl-4- (4-chlorophenyl) -4H-azurenyl)] zirconium dichloride, dimethylsilylenebis [1- (2-ethyl-4-naphthyl) -4H-azulenyl)] zirconium dichloride, diphenylsilylene bis [1- (2-methyl-4- (4-chlorophenyl) -4H-azurenyl)] zirconium dichloride, dimethylsilylene bis [1- (2-ethyl-4- ( 3-fluorobiphenylyl) -4H-azurenyl)] zirconium dichloride, dimethylgermylenebis [1- (2-ethyl-4- (4-chlorophenyl) -4H-azurenyl)] zirconium dichloride, dimethylgermylenebis [1- (2-ethyl-4-phenylindenyl ] And zirconium dichloride zirconium compounds such as chloride can be mentioned. In the above, compounds in which zirconium is replaced with titanium or hafnium can be used in the same manner. In some cases, a mixture of a zirconium compound and a hafnium compound can be used. The chloride can be replaced with other halogen compounds, hydrocarbon groups such as methyl, isobutyl and benzyl, amide groups such as dimethylamide and diethylamide, alkoxide groups such as methoxy group and phenoxy group, hydride groups and the like.
Of these, metallocene compounds obtained by crosslinking an indenyl group or an azulenyl group with silicon or a germyl group are preferable.

The metallocene compound may be used by being supported on an inorganic or organic compound carrier. The carrier is preferably an inorganic or organic porous compound. Specifically, ion-exchange layered silicate, zeolite, SiO ₂ , Al ₂ O ₃ , silica alumina, MgO, ZrO ₂ , TiO ₂ , B Inorganic compounds such as ₂ O ₃ , CaO, ZnO, BaO, ThO ₂ , organic compounds such as porous polyolefin, styrene / divinylbenzene copolymer, olefin / acrylic acid copolymer, or mixtures thereof may be mentioned. it can.

  (Ii) As a co-catalyst that can be activated to a stable ionic state by reacting with a metallocene compound, an organoaluminum oxy compound (for example, an aluminoxane compound), an ion-exchange layered silicate, a Lewis acid, a boron-containing compound, an ionic compound And fluorine-containing organic compounds.

  (Iii) Examples of organoaluminum compounds include trialkylaluminums such as triethylaluminum, triisopropylaluminum, and triisobutylaluminum, dialkylaluminum halides, alkylaluminum sesquihalides, alkylaluminum dihalides, alkylaluminum hydrides, and organoaluminum alkoxides. Can do.

  Examples of the polymerization method include a slurry method using an inert solvent in the presence of the catalyst, a solution method, a gas phase method substantially using no solvent, or a bulk polymerization method using a polymerization monomer as a solvent. Can do.

<Spherical synthetic silica>
The spherical synthetic silica used in the present invention has an average particle diameter of 1 to 6 μm, preferably ² to 4 μm, a specific surface area of 50 to 250 m ² / g, preferably 100 to 200 m ² / g, and a pore volume of 1 ml / g. Or less, preferably 0.35 to 0.87 ml / g, more preferably 0.50 to 0.75 ml / g, and the oil absorption is 150 ml / 100 g or less, preferably 50 to 150 ml / 100 g, more preferably 80 to 150 ml. / 100g.

When the average particle diameter exceeds 6 μm, the transparency and transparency of the film obtained are remarkably deteriorated, and when it is less than 1 μm, the slip property and blocking resistance of the film at the time of winding are inferior. The average particle size is measured by a laser diffraction method.
When the specific surface area is less than 50 m ² / g, the blocking resistance is hardly exhibited at the time of film forming or in the secondary processing, and when it exceeds 250 m ² / g, the surface unevenness becomes prominent and the scratch resistance is deteriorated. Therefore, it is not preferable. The specific surface area is measured by the BET method.
When the pore volume exceeds 1 ml / g, it tends to aggregate when mixed with the powdery propylene polymer, which becomes FE and is inferior in dispersibility. On the other hand, if the pore volume is less than 0.35 ml / g, particles tend to be too hard, and when the films are rubbed, there is a tendency that scratches are likely to occur. When the pore volume is 0.35 ml / g or more, the surface is soft and easily disintegrated, and when the films are rubbed, the particles themselves disintegrate, making it difficult to damage the film. The pore volume is considered to indicate the structure of the primary particles of synthetic silica. If this value is large, the primary particles have a high surface energy. The pore volume is measured by the N ² adsorption method.
When the oil absorption exceeds 150 ml / 100 g, FE tends to occur. The oil absorption indicates the structure of the spherical synthetic silica, but it is considered that the causal relationship is mainly high in the three-dimensional aggregate structure due to the properties such as the oil adsorption. That is, if this value is large, it means that the spherical synthetic silica alone tends to exist as an aggregate. In addition, the measurement of oil absorption amount is based on JIS-K5101-19.

The spherical synthetic silica used for this invention should just belong to spherical silica as a type generally marketed. Specifically, it is preferable that the sphericity is in the range of 0.8 to 1.0 on the basis of the sphericity represented by the following formula.
f = {A / (π / 4)} ^1/2 × Dmax
(Where A is the cross-sectional area of the powder (mm ² ), Dmax is the longest diameter (mm) of the cross-section, and the sphericity value given by this equation is in the range of 0 to 1, 1)
When the sphericity (f) is less than 0.8, the slipperiness of the resulting film tends to deteriorate. The sphericity (f) is measured by measuring the cross-sectional area (mm ² ) of the powder and the longest diameter (mm) of the cross-section. A specific measurement is performed by adding an epoxy resin to the spherical synthetic silica particles to solidify, cutting with a microtome, and measuring the cross section of the fine particles with an image analyzer.

  As a method for producing such spherical synthetic silica, any conventionally known method such as a wet method or a dry method can be employed. In particular, the wet method is preferable because the physical properties can be easily controlled. Wet method synthetic silica is a mixture of sodium silicate and sulfuric acid made from high-purity silica sand, and after forming silica sol, primary particles are formed and three-dimensional silica aggregates are formed by sol-gel polymerization reaction. Can be obtained. In this process, spherical synthetic silica having desired properties can be obtained by changing the production conditions of primary particles. Naturally produced silica is not suitable because it is difficult to obtain the above properties. Commercially available products can be used as the spherical synthetic silica used in the present invention having such specific properties, and specifically, silicon dioxide (trade names Mizupearl K-300 and Mizupearl K-500 manufactured by Mizusawa Chemical Co., Ltd.). ).

  The blending amount of the spherical synthetic silica used in the present invention is selected in the range of 0.01 to 0.5 parts by weight, preferably 0.1 to 0.3 parts by weight with respect to 100 parts by weight of the propylene polymer. If the amount is less than 0.01 parts by weight, the blocking resistance of the film is inferior, and if it exceeds 0.5 parts by weight, the transparency of the film is impaired.

(Lubricant)
The resin composition used in the present invention preferably contains a lubricant.
Examples of the lubricant include fatty acids such as stearic acid and palmitic acid, metal salts of fatty acids such as calcium stearate and magnesium stearate, fatty acid amide, and other derivatives containing a fatty acid forming group.

  Examples of the fatty acid amide include monoamides, substituted amides, bisamides, and the like, which can be used alone or in combination of two or more. Specific examples of monoamides include saturated fatty acid monoamides such as lauric acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, and hydroxystearic acid amide. Further, examples of the unsaturated fatty acid monoamide include oleic acid amide, erucic acid amide, ricinoleic acid amide and the like, and oleic acid amide, erucic acid amide, and behenic acid amide are particularly preferably used.

  Specific examples of substituted amides include N-stearyl stearic acid amide, N-oleyl oleic acid amide, N-stearyl oleic acid amide, N-oleyl stearic acid amide, N-stearyl erucic acid amide, N-oleyl palmitic acid amide Etc.

  Examples of the bisamides include saturated fatty acid bisamides, unsaturated fatty acid bisamides, and aromatic bisamides. Specific examples of saturated fatty acid bisamides include methylene bisstearic acid amide, ethylene biscapric acid amide, ethylene bislauric acid amide, ethylene bisstearic acid amide, ethylene bisisostearic acid amide, ethylene bishydroxystearic acid amide as saturated fatty acid bisamides. , Ethylene bisbehenic acid amide, hexamethylene bis stearic acid amide, hexamethylene bis behenic acid amide, hexamethylene bishydroxystearic acid amide, N, N′-distearyl adipic acid amide, N, N′-di And stearyl sebacic acid amide. Specific examples of the unsaturated fatty acid bisamide include ethylene bisoleic acid amide, hexamethylene bisoleic acid amide, N, N′-dioleyl adipic acid amide, N, N′-dioleyl sebacic acid amide and the like. . Specific examples of the aromatic bisamide include m-xylylene bis stearic acid amide, N, N′-distearylisophthalic acid amide and the like.

  The blending amount of the lubricant is 0.05 to 0.5 parts by weight, preferably 0.05 to 0.3 parts by weight, more preferably 0.05 to 0.1 parts by weight with respect to 100 parts by weight of the propylene polymer. Selected in the range of parts. If the blending amount is less than 0.05 parts by weight, there is a tendency that the opening property and slipperiness at the time of inflation molding are inferior. If the blending amount exceeds 0.5 parts by weight, the protrusion of the lubricant becomes excessive and the transparency is deteriorated. This is not preferable because it tends to occur.

  Compared with conventional silicon dioxide, spherical synthetic silica used in the present invention has a characteristic that the pore volume is small and the amount of oil absorption is particularly small. Since it can improve, the compounding quantity can be reduced about 10% from usual, and the blocking property which is a fault which a lubricant has can also be eased.

(Other ingredients)
In the resin composition used in the present invention, additives that are usually used in propylene-based resins can be appropriately blended as necessary within a range that does not impair the object of the present invention. Examples of the additive include an antioxidant having a molecular weight of 500 or more, a neutralizing agent, a stabilizer, and an inorganic filler.

As the antioxidant, a phosphorus-based antioxidant, a phenol-based antioxidant, and a sulfur-based antioxidant are preferable.
Specific examples of phenolic antioxidants include tris- (3,5-di-t-butyl-4-hydroxybenzyl) -isocyanurate, 1,1,3-tris (2-methyl-4-hydroxy-5). -T-butylphenyl) butane, octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, pentaerythrityl-tetrakis {3- (3,5-di-t-butyl-4 -Hydroxyphenyl) propionate}, 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, 3,9-bis [2- {3 -(3-t-butyl-4-hydroxy-5-methylphenyl) propionyloxy} -1,1-dimethylethyl] -2,4,8,10-tetraoxaspiro [5,5] unde 1,3,5-tris (4-t-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanuric acid and the like, and specific examples of phosphorus antioxidants include tris (mixed, Mono and dinonylphenyl phosphite), tris (2,4-di-t-butylphenyl) phosphite, 4,4'-butylidenebis (3-methyl-6-t-butylphenyl-di-tridecyl) phosphite, 1,1,3-tris (2-methyl-4-di-tridecylphosphite-5-t-butylphenyl) butane, bis (2,4-di-t-butylphenyl) pentaerythritol-di-phosphite Tetrakis (2,4-di-t-butylphenyl) -4,4'-biphenylenediphosphonite, tetrakis (2,4-di-t-butyl-5-methylphenyl)- , 4'-biphenylenediphosphonite, bis (2,6-di-t-butyl-4-methylphenyl) pentaerythritol-di-phosphite, etc., and specific examples of the sulfur-based antioxidant include di- -Stearyl-thio-di-propionate, di-myristyl-thio-di-propionate, pentaerythritol-tetrakis- (3-lauryl-thio-propionate), etc. can be mentioned, respectively.
These can be used alone or in combination of two or more.
Although the compounding quantity of antioxidant is not specifically limited, Preferably it is 0.03-0.5 weight part with respect to 100 weight part of propylene-type polymers. The blending of these antioxidants is extremely effective for forming stability during film forming and secondary processing of the film.

  Specific examples of the neutralizing agent include calcium stearate, zinc stearate, hydrotalcite, and Mizukarak (manufactured by Mizusawa Chemical Co., Ltd.).

  As the stabilizer, a hindered amine stabilizer is preferable. Specific examples of hindered amine stabilizers include polycondensates of dimethyl succinate and 1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine, tetrakis (1,2, 2,6,6-pentamethyl-4-piperidyl) 1,2,3,4-butanetetracarboxylate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, N, N-bis (3-Aminopropyl) ethylenediamine · 2,4-bis [N-butyl-N- (1,2,2,6,6-pentamethyl-4-piperidyl) amino] -6-chloro-1,3,5- Triazine condensate, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, poly [{6- (1,1,3,3-tetramethylbutyl) imino-1,3,5-triazine − , 4-diyl} {(2,2,6,6-tetramethyl-4-piperidyl) imino} hexamethylene {2,2,6,6-tetramethyl-4-piperidyl} imino], poly [(6- Morpholino-s-triazine-2,4-diyl) [(2,2,6,6-tetramethyl-4-piperidyl) imino] hexamethylene {(2,2,6,6-tetramethyl-4-piperidyl) Imino}] and the like.

<Method for preparing resin composition>
As a method for preparing the resin composition used in the present invention, a method of directly adding spherical synthetic silica and an additive to be used as needed to a propylene polymer powder or pellet, a propylene polymer powder, spherical synthetic silica and A method of preparing a master batch composed of additives to be used as needed and adding the master batch to propylene polymer powder or pellets can be mentioned.

  When adjusting the master batch, the conventional silica is inferior in dispersibility when used at a high concentration of about 4 to 8% by weight, and the quality of the master batch is unstable. However, when the spherical synthetic silica specified by the present invention is used, a stable dispersible masterbatch can be obtained even in a concentration range of about 4 to 8% by weight, which is further blended with propylene polymer powder or pellets. Can ensure stable dispersibility.

The resin composition used in the present invention is obtained by mixing a propylene-based polymer, spherical synthetic silica, and additives used as necessary, and then melt-kneading. For mixing, a known method such as a tumbler mixer, a super mixer, a Henschel mixer, a screw blender, or a ribbon blender can be applied. The melt kneading is not particularly limited as long as it is a method of melt kneading at a temperature equal to or higher than the melting point of the propylene polymer particles using, for example, a melt extruder or a Banbury mixer.
The melt-kneading method can be easily carried out with either a single screw extruder or a twin screw extruder, but a twin screw extruder is suitable for more effectively dispersing the spherical synthetic silica.

<Film forming>
The polypropylene film of the present invention can be produced by a known molding method such as a casting method or an inflation method.
The casting method is a method for producing an extrusion-molded body such as a sheet or a film (unstretched film). The resin composition melt-kneaded by an extruder is extruded from a T-die and passed through a roll through which a coolant such as water passes. Since the film is cooled by being brought into contact with the film and generally has a good transparency and a good thickness accuracy, it is a preferable production method for the film.

  In the polypropylene film of the present invention, when it is molded and used as a single layer film, the thickness is usually 5 to 500 μm, preferably 10 to 200 μm. If the thickness is less than 5 μm, processing becomes difficult.

  The polypropylene film of the present invention may be in the form of a stretched film. In that case, the stretched film can be produced by stretching the sheet or film obtained as described above with a known stretching apparatus. Examples of these stretching apparatuses include a tenter method, a simultaneous biaxial stretching method, and a uniaxial stretching method. The stretch ratio of the stretched film is desirably 10 to 70 times in the case of a biaxially stretched film, and desirably 2 to 10 times in the case of a uniaxially stretched film. Moreover, it is desirable that the thickness of the stretched film is usually 5 to 200 μm.

  Moreover, the polypropylene film of this invention can be used as a composite film with another base material. The substrate can be selected from, for example, any polymer capable of film forming, cellophane, paper, fiber structure, aluminum foil, and the like.

  Examples of the polymer that can be formed into a film include polyamide resins, polyester resins, polyethylene, ethylene-vinyl acetate copolymers, polyolefin resins such as ethylene-methacrylic acid copolymers, polyvinyl chloride, polyvinylidene chloride, From the vinyl alcohol copolymer, etc., it can be selected according to the purpose of making the composite film in consideration of the transparency, rigidity, adhesiveness, printability, gas barrier property and the like.

  When the substrate is stretchable, it may be stretched uniaxially or biaxially. The composite film can be produced by a known technique such as a coextrusion method, a dry lamination method, an extrusion lamination method, or a combination thereof. In the case of the coextrusion method, the dry lamination method, and the extrusion lamination method, the thickness of the layer made of the polypropylene film of the present invention is preferably 0.5 to 200 μm, more preferably 1 to 150 μm, and more preferably 3 to 100 μm. Is more preferable.

  Since the polypropylene film of the present invention is rich in scratch resistance, it is suitable for metal vapor deposition film applications that are easily noticeable even with fine scratches.

As a method for producing a metal vapor-deposited film, simultaneously with film formation, the surface is subjected to corona discharge treatment, and the wetting index of the treated surface is adjusted to 40 to 45 dyn / cm, for example, about 45 dyn / cm and wound. The wound film is placed on a vacuum deposition apparatus, adjusted to a vacuum degree of 1.0 × 10 ^{−4 to} 1.0 × 10 ⁻⁵ Torr, for example, 1.0 × 10 ⁻⁵ Torr, and then thickened on the surface. A vapor deposition film is obtained by performing metal deposition of 40 to 70 nm.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited by these examples without departing from the gist thereof. In addition, the production method of the film sample of an Example and a comparative example, and a metal vapor deposition film sample, the measuring method of the physical property about this sample, and the reference | standard of evaluation are as follows.

(How to make a film sample)
The resin compositions of each Example and each Comparative Example were each extruded at a melting temperature of 220 ° C. using a T-die extruder, rapidly cooled with an air knife and a cooling roll having a surface temperature of 30 ° C., and immediately formed into a film shape. Corona discharge treatment was performed so that the wetting index on one side was 40 dyne / cm, and the film was wound up as a film having a thickness of 25 μm and a width of 30 cm.

(Metal vapor deposition film sample preparation method)
The surface of the film obtained according to the above sample preparation method subjected to the corona discharge treatment was adjusted to a vacuum degree of 1.0 × 10 ⁻⁵ Torr by a vacuum deposition apparatus, and then the surface had a thickness of 40 to 70 nm. Aluminum deposition was performed.

(Measuring method)
(1) Slip property: The coefficient of static friction between non-corona treated surfaces of the base film measured by the method defined in ASTM D 523 after leaving the film obtained by the above method in a constant temperature room at 23 ° C. for one day. Asked. It shows that slip property is so good that this value is small.

(2) Degree of blocking: The film obtained by the above method was adjusted to a size of 30 cm (width) × 20 cm (length), and the corona non-treated surfaces of these films were overlapped with each other under a load of 15 kg / cm ^2. After leaving in a 40 ° C. gear oven (Tabai Espec / Tabai Gear Oven: GPH-100) for 24 hours, a test piece cut to ² cm (width) × 15 cm (length) and an overlapping area of 10 cm ² was subjected to a tensile test. The force required for detachment (peeling when a tensile force was applied in the longitudinal direction to the overlapping part of the sample) was measured using a machine (Toyo Seiki Seisakusho Co., Ltd./C-type shopper tensile tester). . It shows that blocking resistance is so good that this value is small.

(3) Scratch resistance (scratch resistance): The scratch resistance test was measured by the scratch tester shown in FIGS. 1 and 2 as follows.
The vapor deposition surface of the metal vapor-deposited film 3 (100 mm × 250 mm) obtained as described above is placed on the lower surface of the support portion 2 that is attached to the pole portion standing on the scratch tester body 1 so as to be rotatable in the horizontal direction. Fix it. Next, after fixing to the wiper part 5 with a double-sided tape so that the corona-treated surface of the film 4 (80 mm × 80 mm) before metal deposition becomes the surface, the support part 2 is extended from the wiper part 5 and the scratch tester body 1. It is moved horizontally and fixed between the provided acrylic plates 6. Next, the wiper unit 5 is started, reciprocated once, and the surface of the metal vapor deposition film 3 is slid, and then the surface state of the metal vapor deposition film 3 is visually observed with an actual microscope, and the damaged state is evaluated according to the following criteria. did.
Good: A state in which no deep scratches are seen, and a few shallow and fine scratches are seen.
Slightly poor: A state in which no deep scratches are seen and several shallow and thick scratches are seen.
Defect: A state where several deep and thick scratches are seen.
Extremely bad: Many deep and thick scratches are seen.

(4) Dispersibility: The appearance of the film obtained by the above method was visually observed, and the dispersibility was evaluated according to the following criteria.
A: Overall, almost no FE.
○: A state in which no large FE is observed and a small number of small FEs are observed.
Δ: A state where a small number of large FEs are seen.
X: A state in which many small FEs are seen as a whole.
XX: A state in which a large number of large and small FEs are seen as a whole.

(5) Yellowing resistance: About 30 g of pellets obtained from Examples 2, 5 and Comparative Examples 3, 5, 7, 9, 11, 13, 15 were used as samples, and a color difference meter (manufactured by Nippon Denshoku Industries Co., Ltd./COLORMTER) : ZE-2000), YI [YI- (1)] was measured in advance according to JIS Z-8722. Each of these samples was allowed to stand for 60 days in a 40 ° C. gear oven (manufactured by Tabai Espec / Tabai Gear Oven: GPH-100), and then YI [YI- (2)] was measured, and [YI- (2 )] And [YI- (1)]. The smaller this difference, the better the yellowing resistance.

(6) Fisheye (FE): The FE present in the film obtained by the above method was calculated by visual observation and converted to the number present in 1 m ² . The appearance was good when the number of FE was 20 / m ² or less.

(7) Haze: A value (unit%) obtained by measuring the film obtained by the above method according to ASTM D 1003 is shown as haze. It means that transparency and film appearance are so good that this value is small.

Examples 1-5, Comparative Examples 1-15
Various ABs having properties and physical properties shown in Table 1 are added to 100 parts by weight of a propylene homopolymer having a crystal melting point (Tm) of 160 ° C. and an MFR of 7.0 obtained by a Ziegler catalyst (FB3HAT powder manufactured by Nippon Polypro Co., Ltd.). Each of the types shown in Table 2 was selected from the agents, and added in the amount shown in Table 2, and tetrakis- [methylene-3- (3 ′, 5′-di-t-butyl-) was used as an antioxidant. 4'-hydroxyphenyl) propionate] 0.05 parts by weight of methane, 0.05 parts by weight of tris (2,4-di-t-butylphenyl) -phosphite, 0.05 parts by weight of calcium stearate as a neutralizing agent After adding and mixing with a Henschel mixer for 2 minutes, pellets were formed using an extruder adjusted to an extrusion temperature of 230 ° C. Obtained.
Table 2 shows the characteristics of the films obtained in each Example and each Comparative Example.

  As is apparent from Table 2, the polypropylene film formed by blending the spherical synthetic silica having the physical properties specified in the present invention is any of slip property, blocking resistance, scratch resistance, dispersibility, FE characteristics, and yellowing resistance. In contrast, when synthetic silica that does not satisfy the physical properties specified in the present invention is used, slip properties, blocking resistance, scratch resistance, dispersibility, FE characteristics, yellowing resistance, haze are excellent. It can be seen that a high-quality polypropylene film cannot be obtained because any one of the above characteristics is poor.

Examples 6-9, Comparative Examples 16-19
AB agent of the kind and addition amount shown in Table 3 in 100 parts by weight of propylene homopolymer (FB3HAT powder manufactured by Nippon Polypro Co., Ltd.) having a crystal melting point (Tm) of 160 ° C. and MFR of 7.0 obtained by the Ziegler catalyst. And a slip agent (erucic acid amide), and 0.05 weight of tetrakis- [methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate] methane as an antioxidant Parts, 0.05 parts by weight of tris (2,4-di-t-butylphenyl) -phosphite, 0.05 parts by weight of calcium stearate as a neutralizing agent, and after stirring and mixing with a Henschel mixer for 2 minutes, extrusion Using the extruder adjusted to the temperature of 230 degreeC, it was set as the pellet, the film sample was obtained by the above-mentioned method, and the said measurement was implemented. The results are shown in Table 3.

  As is apparent from Table 3, the polypropylene film using the spherical synthetic silica having the physical properties specified in the present invention has good haze, slip properties, blocking resistance, scratch resistance, dispersibility, and FE characteristics. It was. Thus, compared with the conventional synthetic silica, the spherical synthetic silica having the physical properties specified in the present invention is rich in synergistic effect with the slip agent and has an extremely high effect of improving the slip property.

Examples 10 and 11, Comparative Examples 20 and 21
Table 100 shows the types and amounts added in 100 parts by weight of propylene-ethylene random copolymer (powder of WFX4T manufactured by Nippon Polypro Co., Ltd.) having a crystal melting point (Tm) of 125 ° C. and MFR of 7.0 obtained by the metallocene catalyst. In addition, 0.05 parts by weight of tetrakis- [methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate] methane as an antioxidant and tris (2 , 4-di-t-butylphenyl) -phosphite, 0.05 parts by weight of calcium stearate as a neutralizing agent, and after stirring and mixing with a Henschel mixer for 2 minutes, the extrusion temperature was adjusted to 230 ° C. Using the resulting extruder, pellets were obtained, film samples were obtained by the method described above, and the above measurements were carried out. The results are shown in Table 4.

  As is apparent from Table 4, the polypropylene film using the spherical synthetic silica having the physical properties specified in the present invention is based on a propylene-ethylene random copolymer using a metallocene catalyst, and the haze, slip resistance, Blocking properties, scratch resistance, dispersibility, and FE properties were all good.

It is a schematic side view of a scratch tester. It is the upper surface schematic of a scratch tester.

Explanation of symbols

1 Scratch tester body 2 Supporting part 3 Metal vapor deposition film (test piece)
4 Film before metal deposition 5 Wiper part 6 Acrylic plate

Claims (4)

With respect to 100 parts by weight of a propylene-based polymer composed of a propylene homopolymer or a propylene-α-olefin copolymer, the average particle diameter is 1 to 6 μm, the specific surface area by the BET method is 50 to 250 m ² / g, and the pore volume is A polypropylene film obtained from a resin composition comprising 0.01 to 0.5 parts by weight of spherical synthetic silica having an oil absorption of 1 ml / g or less and an oil absorption of 150 ml / 100 g or less.   The polypropylene film according to claim 1, wherein the propylene polymer is polymerized using a metallocene catalyst.   The polypropylene film according to claim 1 or 2, wherein the resin composition further comprises 0.05 to 0.5 parts by weight of a lubricant with respect to 100 parts by weight of the propylene polymer.   A metal vapor-deposited film using the polypropylene film according to any one of claims 1 to 3.

Images