CN110225937A

CN110225937A - Biaxially oriented polypropylene film

Info

Publication number: CN110225937A
Application number: CN201880007838.XA
Authority: CN
Inventors: 久万琢也; 冈田一马; 山中康平; 大仓正寿
Original assignee: Toray Industries Inc
Current assignee: Toray Industries Inc
Priority date: 2017-02-07
Filing date: 2018-02-07
Publication date: 2019-09-10
Anticipated expiration: 2038-02-07
Also published as: CN110225937B; WO2018147334A1; JPWO2018147334A1; JP7003920B2; JP2022044604A; JP7205611B2; KR20190111902A; KR102455834B1

Abstract

A kind of biaxially oriented polypropylene film, the maximum height roughness of the one side of biaxially oriented polypropylene film is being denoted as Sz1, when the maximum height roughness of another side is denoted as Sz2 (wherein Sz1≤Sz2), Sz1 is 50~500nm, at least one side with 5 frequencies with upper process, there are the protrusions that long side is 10 μm or less and height is 50~200nm in the area of 100 μm of square.It is excellent to provide surface smoothness, the transparency, and sliding property, operability, windability excellent polypropylene screen.

Description

Biaxially oriented polypropylene film

Technical field

The present invention relates to surface smoothness, the transparency are excellent, and sliding property, operability, windability excellent polypropylene Film and the bonding film roll for having used the polypropylene screen.

Background technique

The transparency, mechanical property, the electrical characteristics of polypropylene screen etc. are excellent, are accordingly used in packaging applicationss, demoulding purposes, glue With various uses such as purposes, cable packet cicada, the electrical applications that capacitor is representative.Especially because the release property on surface, machinery Excellent, therefore film for demoulding, the process film for the various components such as be suitable as plastic products, building materials, optical component.

Requirement characteristic to film for demoulding is suitably set according to its usage, but because of the small-sized of equipment in recent years Change, high precision int, film and high-quality also are required to the product for becoming protected object sometimes, if the surface of polypropylene screen is flat Slip is poor, then in the mold release film as such as optics component in use, the concave-convex surface of film is transferred to optics component sometimes And the identification of product is affected.In addition, if the transparency of polypropylene screen is poor, then after being bonded with product, carrying out Sometimes become obstruction when the process inspections such as Observation of Defects.

On the other hand, the excellent general sliding property of film of surface smoothness, the transparency is poor, sometimes the conveying work in film Fold or operability are generated in sequence, rolling step and post-processing procedure etc. to be reduced.

As the means for improving the sliding property of polypropylene screen, such as the use of film surface layer is described in Patent Documents 1 to 3 The example of easily sliding particle.

As the example without using easily sliding particle, describes addition vinylite in patent document 4 and formed on surface Concave-convex example.

The example that film surface layer uses the olefin-based resin comprising 4-methyl-1-pentene unit is described in patent document 5~8 Son.

Existing technical literature

Patent document

Patent document 1: Japanese Unexamined Patent Publication 2007-105893 bulletin

Patent document 2: Japanese Unexamined Patent Publication 2005-138386 bulletin

Patent document 3: Japanese Unexamined Patent Publication 11-048335 bulletin

Patent document 4: Japanese Unexamined Patent Publication 2002-40667 bulletin

Patent document 5: Japanese Unexamined Patent Publication 2015-107612 bulletin

Patent document 6: Japanese Unexamined Patent Publication 2004-114419 bulletin

Patent document 7: Japanese Unexamined Patent Publication 2008-189795 bulletin

Patent document 8: Japanese Unexamined Patent Publication 2005-280125 bulletin

Summary of the invention

Problems to be solved by the invention

It is low with the compatibility of particle in Patent Documents 1 to 3, however because of polyacrylic high mold release, in film work Particle falls off in sequence, post-processing procedure, or in the case where using as film for demoulding, process film, particle is attached to system sometimes Product.In addition, due to mist degree height, the transparency is insufficient in patent document 1,2, therefore cannot be used for implementing defects detection sometimes Process.Although the transparency is excellent in patent document 3, the partial size of used particle is big, therefore surface smoothness is not filled sometimes Point.

In patent document 4, the surface smoothness at the back side is insufficient, the shape at the back side sometimes when being bonded and winding with product It is transferred to product.In addition, sliding property is insufficient, when coating adhesive layer is used as protective film etc., in the feelings that winding is difficult The defects of air trapping occurs is sometimes prone under condition.

In patent document 5,6 comprising 4-methyl-1-pentene unit olefin-based resin addition at concentrations up to 5% or more, Therefore the protrusion of film surface becomes thick, when coating adhesive layer is used as protective film etc., in the case where winding difficult It is sometimes prone to the defects of air trapping occurs, additionally due to the mist degree of film is also high, therefore defects detection cannot be implemented sometimes.This Outside, although the addition concentration of the olefin-based resin comprising 4- methyl-1 amylene unit in patent document 7,8 is low, temperature is squeezed out Degree, the temperature of curtain coating drum are high, and the protrusion of film surface becomes thick, and are being bonded with product and the shape transfer at the back side sometimes when winding To product.

Project of the invention is to solve the above problems.That is, offer surface smoothness, the transparency are excellent, and sliding property, behaviour The property made, windability excellent polypropylene screen.

The method used for solving the problem

In order to solve the above problems, it achieves the goal, biaxially oriented polypropylene film of the invention is characterized in that, by twin shaft The maximum height roughness of the one side of oriented polypropylene film is denoted as Sz1, and the maximum height roughness of another side is denoted as Sz2 (its Middle Sz1≤Sz2) when, Sz1 be 50~500nm, at least one side in the area of 100 μm of square have 5 with upper process There are the protrusions that long side is 10 μm or less and height is 50~200nm for frequency.

The effect of invention

Biaxially oriented polypropylene film of the invention due to surface smoothness, the transparency it is excellent, and sliding property, operability, It is windability excellent, therefore the industrial film such as base material film, cover film, protective film that can be suitable as coating.

Specific embodiment

The maximum height roughness of one side is being denoted as Sz1, most by another side by biaxially oriented polypropylene film of the invention When big height roughness is denoted as Sz2 (wherein Sz1≤Sz2), Sz1 is 50~500nm.So-called maximum height roughness indicates most The sum of big height of projection and maximum cup depth.Sz1 is more preferably 50~400nm, further preferably 100~300nm, into one Step is preferably 120~280nm.If Sz1 is less than 50nm, film surface is excessively smooth, in the film conveying that will be film-made out or winding When, operational, windability reduction sometimes.If Sz1 is more than 500nm, as base material film, cover film in use, existing sometimes The surface transfer of product is concave-convex.In order to make Sz1 above range, preferably make that the raw material of film forms, the lamination of film is configured to aftermentioned Range, in addition, curtain coating (the piece chemical industry sequence of the resin of melting extrusion) condition, the longitudinal stretching condition when being film-made film are aftermentioned In the range of, reduce the β crystalline substance of cast sheet.In addition, particularly preferably making the blending condition of acrylic resin and other resins and melting Condition when melting extrusion is to control the dispersion of resin in aftermentioned range.However, the value phase of the maximum height roughness on two sides Deng in the case where, the maximum height roughness of the contact surface with curtain coating drum is denoted as Sz1.

Biaxially oriented polypropylene film of the invention, at least one side to have 5 or more to dash forward in the area of 100 μm of square There are the protrusions that long side is 10 μm or less and height is 50~200nm for the frequency risen.Thereby, it is possible to suitably control by film roll around When air trapping, air discharge property, smooth film corrugationless is wound nattily.Especially to Biaially oriented polypropylene Film coats adhesive layer, and when winding film roll in the case where not across mold release film, coefficient of friction becomes larger, therefore is easy to draw in winding Enter fold.The back side of polypropylene screen connects with Nian Jie layer surface, therefore the surface shape at the back side brings big influence to windability, Consequently found that the contact area at adhesive layer surface and the back side can be made small by becoming above-mentioned protrusion density, winding fold is not easy It introduces, it is windability to become good.On polypropylene screen surface there are the coarse protrusion such as fibrinogen and partes glabra, but fibrinogen sometimes Major diameter etc. coarse protrusion is big, with adhesive layer face contact, less contributes to windability improvement, it is prone to which air trapping etc. lacks It falls into.It was found that by make partes glabra largely exist can with microspike of the adhesive layer point contact with particular protrusion height, major diameter, It can improve in the state of maintaining flatness windability.If the height of protrusion is less than 50nm, sliding property is improved sometimes It does not contribute, windability raising is not contributed.On the other hand, if the height of protrusion is more than 200nm, sometimes in winding Air easily enters and is easy to generate defect between protrusion.In addition, long side is more than contribution of 10 μm of the protrusion to windability raising It is small, it is sometimes prone to the defects of generating air trapping.From the viewpoint of windability raising, protrusion frequency is more preferably 7 or more, Further preferably 10 or more, particularly preferably 50 or more, most preferably 100 or more.If protrusion frequency is less than 5 It is a, then sliding property raising is not contributed sometimes, windability reduction.In protruding condition above range in order to make film surface, Make curtain coating (the piece chemical industry of the resin of melting extrusion when composition, the method for adjustment, the lamination composition of film, film film of the raw material of film Sequence) condition, longitudinal stretching condition be aftermentioned range in be effective.

The maximum height roughness of one side is being denoted as Sz1, most by another side by biaxially oriented polypropylene film of the invention When big height roughness is denoted as Sz2 (wherein Sz1≤Sz2), maximum height roughness Sz2 is preferably 100~1000nm.Sz2 is more Preferably 200~800nm, further preferably 300~700nm, further preferably 500~700nm.If Sz2 is less than 100nm, then film surface is excessively smooth, in the film conveying that will be film-made out or winding, operational, windability reduction sometimes.If Sz2 is more than 1000nm, then as base material film, cover film in use, sometimes concave-convex in the surface transfer of product.In order to make Sz2 For above range, preferably make that the raw material of film forms, the lamination of film is configured to aftermentioned range, in addition, curtain coating when being film-made film (the piece chemical industry sequence of the resin of melting extrusion) condition, longitudinal stretching condition are to reduce the β crystalline substance of cast sheet in aftermentioned range.

The value of the preferred Sz2/Sz1 of biaxially oriented polypropylene film of the invention is 1 or more and 3 or less.More preferably 1.5 or more And 3 or less.If the value of Sz2/Sz1 is more than that 3, Sz1 is too small, and film surface is excessively smooth, in the film conveying that will be film-made out or volume Around when, operability, windability reduction sometimes；Sz2 is excessive, as base material film, cover film in use, sometimes on the surface of product Transfer is concave-convex.In order to make the value above range of Sz2/Sz1, preferably make that the raw material of film forms, the lamination of film is configured to aftermentioned Range, in addition, curtain coating (the piece chemical industry sequence of the resin of melting extrusion) condition, the longitudinal stretching condition when being film-made film are aftermentioned In range, reduce the β crystalline substance of cast sheet.

The number of the preferred flake of biaxially oriented polypropylene film of the invention is 20/m²Below.The number of flake is more preferable For 10/m²Hereinafter, further preferably 5/m²Below.If the number of flake is more than 20/m², then as display Sometimes yield rate reduction when component etc. requires the protective film of the product of high-quality, manufacture to be used with base material film.In order to make flake Number is above range, is configured to the lamination of the composition of raw material, method of adjustment, film in aftermentioned range, makes adding in raw material The reason of adding agent ingredient, carrying out heat deterioration and the become flake usage amount reduction of such resin is effective.In addition, making film Condition when film is that raw material is melted to and is removed by filtration before piece foreign matter, reduces resin in aftermentioned range Delay portion be effective.

The preferred mist degree of biaxially oriented polypropylene film of the invention is 1% or less.More preferably 0.9% hereinafter, further excellent 0.8% is selected as hereinafter, further preferably 0.7% or less.If mist degree is more than 1%, sometimes the surface roughness of film surface Greatly, transferring surface shape is to adherend.In addition, protective film, manufacture in the product for requiring high-quality as display member etc. Sometimes it cannot implement defects detection when being used with base material film in the state of being bonded with product.From the viewpoint of the transparency, mist The degree the low the more preferred, and implementing upper 0.05% or so is lower limit.In order to make mist degree above range, preferably form the raw material of film, The lamination of film is configured to aftermentioned range, prevents transparent deterioration as caused by particle etc., in addition, curtain coating when being film-made film Condition, longitudinal stretching condition are to reduce the β crystalline substance of cast sheet in aftermentioned range.In addition, no matter including 4-methyl-1-pentene How is the addition concentration of the olefin-based resin of unit, in order to improve the transparent flatness of film, particularly preferably makes the stream after squeezing out Prolong bulging temperature and is quenched to 30 DEG C hereinafter, and in order to divide the olefin-based resin comprising 4-methyl-1-pentene unit imperceptibly Dissipate the method in acrylic resin, being kneaded it with biaxial extruder in advance and granulating.

The Young's modulus E in biaxially oriented polypropylene film preferred length direction of the invention_MDFor 1GPa or more.If length side To Young's modulus E_MDLess than 1GPa, then when using as surface protection film and being removed from adherend, sometimes because of removing Power, film are extended and are ruptured, or remain removing trace in adherend.In addition, the film elongation because of conveyance tension when being bonded sometimes. E_MDMore preferably 1.2GPa or more, further preferably 1.4GPa or more.E_MDIt is more strong the more preferred, but substantially 10GPa or so is The upper limit.In order to make E_MDValue be above range, preferably make film raw material group become aftermentioned range, in addition, making film forming condition Aftermentioned range, it is film is biaxial stretch-formed with high magnification and obtain base material film.

The Young's modulus E in biaxially oriented polypropylene film preferable width direction of the invention_TDFor 1GPa or more.If E_TDIt is small In 1GPa, then in conveying, film is easy to introduce fold, or is bonded with the film as adherend and wound into rolls is saved When, it is rolled up sometimes because of the change in size of film and generates fold etc..E_TDMore preferably 1.5GPa or more, further preferably 2.0GPa More than, further preferably 2.5GPa or more.E_TDIt is more strong the more preferred, but substantially 10GPa or so is the upper limit.In order to make E_TD's Value is above range, so that the raw material group of film is become aftermentioned range, in addition, making the aftermentioned range of film forming condition, by film It is biaxial stretch-formed with high magnification and obtain base material film.

In addition, in this application, the direction parallel with the film direction of film is known as to be film-made direction or length direction or MD Orthogonal with film direction direction in film surface is known as width direction or the direction TD by direction.

Percent thermal shrinkage after 110 DEG C of heat treatments in biaxially oriented polypropylene film preferable width direction of the invention is 1.0% Below.More preferably 0.8% hereinafter, further preferably 0.5% hereinafter, further preferably 0.3% or less.If width side To percent thermal shrinkage be more than 1.0%, then for example as protective film, cover film and after being bonded with other raw material, by applying Whens the drying process etc. of heating etc., film is deformed and is peeled off or fold sometimes.In addition, being rolled up being bonded with the film as adherend When being coiled into web-like and having carried out preservation, if environment temperature rises, is rolled up sometimes because of the change in size of film and generate fold etc.. The lower limit of percent thermal shrinkage is not particularly limited, but also membrane swelling sometimes, and substantially -2.0% or so be lower limit.In order to make to be heat-shrinked Rate is above range, and so that the raw material group of film is become aftermentioned range especially makes in addition, making the aftermentioned range of film forming condition It is effective that heat setting, relaxation condition after biaxial stretch-formed, which are aftermentioned range,.Here so-called percent thermal shrinkage refers to, for film Width direction, cut out width 10mm, 5, sample of length 200mm (measurement direction), stamp mark in the position away from both ends 25mm It is denoted as measuring the distance between graticule with Universal projector and being denoted as the long (l of examination for graticule₀), next, test film is clamped into paper And taken out after sixty minutes in heat preservation in being heated in 110 DEG C of baking oven in the state of zero loading, after cooling down at room temperature, use is omnipotent Projector measures size (l₁), 5 average value is denoted as percent thermal shrinkage by the value found out using following formula.

Percent thermal shrinkage={ (l₀-l₁)/l₀} × 100 (%).

The thickness of biaxially oriented polypropylene film of the invention appropriate adjustment depending on the application, is not particularly limited, but preferably It is 5 μm or more and 100 μm or less.If thickness is less than 5 μm, operating difficulties sometimes, if it exceeds 100 μm, then resin sometimes Amount increases and productivity reduces.Even if biaxially oriented polypropylene film thickness thinning of the invention, intensity (Young's modulus) is also excellent, Therefore operability can be kept.In order to play such feature, thickness is more preferably 5 μm or more and 40 μm hereinafter, further excellent 5 μm or more and 30 μm are selected as hereinafter, most preferably 5 μm or more and 25 μm or less.Thickness can not be such that other physical property deteriorate In range, adjusted by the screw speed of extruder, non-stretched width, film speed, stretching ratio etc..

As long as biaxially oriented polypropylene film of the invention meets above-mentioned characteristic, can be single layer film, or 2 layers with On stack membrane, but from the viewpoint of having the transparency concurrently with sliding property, preferably at least 2 layers of lamination is constituted.

Next the raw material of biaxially oriented polypropylene film of the invention is illustrated, but is not necessarily limited to this.

Biaxially oriented polypropylene film of the invention is the film using polypropylene as principal component.Here, so-called in the present invention " principal component " refers to that specific ingredient ratio shared in whole components is 50 mass % or more, more preferably 90 mass % More than, further preferably 95 mass % or more, further preferably 96 mass % or more, further preferably 97 mass % with On, further preferably 98 mass % or more.

As long as pp material used in biaxially oriented polypropylene film of the invention meets above-mentioned physical property, without special It limits, it is preferable to use crystalline polypropylene (hereinafter, pp material A) from the viewpoint of intensity, heat resistance.

Preferably, pp material A is preferably that cold xylene soluble portions (following CXS) is 4 mass % or less and interior disappears Revolve the polypropylene that five unit composition ratios are 0.90 or more.If these conditions are not met, then stability is poor or film for film sometimes The reduction of strength reduction or dimensional stability and heat resistance becomes larger.

Here so-called cold xylene soluble portions (CXS), refer to after being completely dissolved sample with dimethylbenzene, analyse at room temperature When out, the polypropylene constituent that is dissolved in dimethylbenzene, it is believed that be equivalent to because of reasons such as stereoregularity are low, molecular weight is low And it is difficult to the ingredient crystallized.If such ingredient largely includes in resin, the thermal dimensional stability of film is poor sometimes.Cause This, CXS is preferably 4 mass % hereinafter, further preferably 3 mass % are hereinafter, particularly preferably 2 mass % or less.CXS is lower It is the more preferred, but 0.1 mass % or so is lower limit.In order to become the polypropylene with such CXS, raising can be used and set The method of catalytic activity when rouge, by the resulting resin method that solvent or propylene monomer wash itself, using metal The methods of the method for luxuriant PP.

From the same viewpoint, the five unit composition ratio of meso of pp material A is preferably 0.90 or more, further Preferably 0.94 or more.Five unit composition ratio of meso is the polyacrylic knot of expression measured by nuclear magnetic resonance method (NMR method) The index of the stereoregularity of crystal phase, the more high then crystallinity of the numerical value is higher, and fusing point is higher, and the dimensional stability under high temperature is got over Height is therefore preferred.About the upper limit of five unit composition ratio of meso, without special provision.In order to obtain structure rule vertical in this way The high resin of whole property, it is preferred to use with the method that normal heptane equal solvent washs resulting toner, suitably urge Selection, method of the selection of composition of agent and/or co-catalyst etc..

In addition, as pp material A, more preferable melt flow rate (MFR) (MFR) be 1~10g/10 minutes (230 DEG C, 21.18N loading), the pp material of the range of particularly preferably 2~5g/10 minutes (230 DEG C, 21.18N loading) is from film It is preferred from the viewpoint of property, film-strength.In order to make melt flow rate (MFR) (MFR) to be above-mentioned value, using control mean molecule Amount, method of molecular weight distribution etc..

It, can be containing by other unsaturated hydrocarbons shapes in the range of not damaging the purpose of the present invention as pp material A At copolymer composition etc., non-homopolymerizing propylene can also be blended.As such copolymer composition, constitute blend monomer component, Such as ethylene, propylene (in the case where the blend being copolymerized), 1- butylene, 1- amylene, 3- Methyl-1-pentene, 3- can be enumerated Methyl-1-butylene, 1- hexene, 4-methyl-1-pentene, 5- ethyl-1- hexene, 1- octene, 1- decene, 1- dodecylene, ethylene Cyclohexene, styrene, allyl benzene, cyclopentene, norbornene, 5- methyl -2- norbornene etc..About copolymerization amount or blending Amount, preferably to be copolymerized meter less than 1mol%, is calculated as from the aspect of resistance to insulation breakdown characteristic, dimensional stability with blending amount 10 mass %.

Furthermore biaxially oriented polypropylene film of the invention is steady from intensity raising, size other than above-mentioned pp material A From the viewpoint of qualitative raising, branched polypropylene H can be contained.Here so-called branched polypropylene H, is relative to carbon atom 10,000 have at 5 with the polypropylene of lower branched structure.The presence of the branched structure can pass through¹The proton of H-NMR spectrum Than confirming.In the case of containing, it is preferable that preferably 0.05~10 mass %, further preferably 0.5~8 mass %, into One step preferably comprises 1~5 mass %.It, can be by the cooling of the resin sheet of melting extrusion by containing above-mentioned branched polypropylene H The spherulite size generated in (curtain coating) process controls small, can obtain the excellent polypropylene of the transparency, intensity, surface smoothness Film.

As above-mentioned branched polypropylene H, from the viewpoint of film formation property, preferably melt flow rate (MFR) (MFR) 1~ 20g/10 minutes ranges, more preferably in 1~10g/10 minutes ranges.Furthermore about melting tension, preferably 1~ The range of 30cN, more preferably in the range of 2~20cN.

The ethylene ingredient that biaxially oriented polypropylene film of the invention preferably includes in the polyacrylic polymer for constituting film Content is 10 mass % or less.More preferably 5 mass % are hereinafter, further preferably 3 mass % or less.The content of ethylene ingredient More, then crystallinity more reduces, and is more easy to make transparent raising, but if the content of ethylene ingredient is more than 10 mass %, then has When strength reduction or heat resistance reduce and percent thermal shrinkage deteriorate.In addition, resin is easy to deteriorate in extrusion operation sometimes, in film Flake be easy to generate.The content of ethylene ingredient can be 0%, but reduce from crystallinity, the viewpoint for being easy to improve the transparency Consideration preferably comprises 0.1% or more.

From the viewpoint of the transparency, heat resistance, intensity, biaxially oriented polypropylene film of the invention preferably comprises the poly- of film The content for closing the polyacrylic polymer for including in object is 95 mass % or more.More preferably 96 mass % or more, further preferably For 97 mass % or more, further preferably 98 mass % or more.

Biaxially oriented polypropylene film of the invention preferably comprises the resin that fusing point is 180 DEG C or more (hereinafter, high-melting-point tree Rouge).Fusing point is more preferably 180 DEG C or more and 240 DEG C or less.By making the surface layer of film contain resin with high melting point, in aftermentioned item Membranization under part can make to slide so as to form the protrusion that 10 μm of above-mentioned long side or less and height are 50~200nm Property improve.In such cases it is preferred to be by least 2 layers of film constituted of surface layer (I) and base (II), and surface layer (I) Include resin with high melting point.If resin with high melting point is made to be present in surface layer (I), in aftermentioned melting extrusion process, fusing and Be dispersed in polypropylene, can be indeformable in stretching process and form above-mentioned protrusion.In order to make to be formed by protrusion Such fine protrusion is stated, the micro disperse in melting extrusion process is needed to be with polyacrylic compatibility height in polypropylene Important.Consider that resin with high melting point is preferably olefin-based resin from the viewpoint, in olefin-based resin, particularly preferably with packet The olefin-based resin of the unit containing 4-methyl-1-pentene is as principal component.Resin and non-olefinic comprising 4-methyl-1-pentene unit It is that resin is high compared to the compatibility with acrylic resin, therefore dispersibility can be improved.As including 4- methyl-1 amylene unit Olefin-based resin, may be exemplified for example, Mitsui Chemicals, Inc's system " TPX " (registered trademark) DX310, " TPX " (registrar Mark) DX231, " TPX " (registered trademark) MX004 etc..

It include 4- methyl-1-pentene among the resin combination of surface layer (I) in biaxially oriented polypropylene film of the invention The content of the olefin-based resin of alkene unit is preferably 0.1~4.5 mass %, more preferably 0.1~4 mass %, further preferably For 0.1~3 mass %, further preferably 0.1~2.5 mass %.In the olefin-based resin comprising 4-methyl-1-pentene unit Content more than in the case where 5 mass %, protrusion becomes the long mountain range shape of length direction sometimes, is formed by the length of protrusion sometimes Side is more than 10 μm, the height of protrusion is more than 200nm, as base material film, cover film in use, sometimes in the surface transfer of product Bumps, when being used as protective film biaxially oriented polypropylene film coating adhesive layer of the invention etc., difficult in winding In the case of be sometimes prone to generate air trapping the defects of.In the case where content is less than 0.1 mass %, it is formed by protrusion sometimes Underfrequency, to sliding property raising do not contribute, windability reduction.

It is preferred that containing resin with high melting point on the surface layer of biaxially oriented polypropylene film of the invention, but in order to make film surface institute shape At protrusion be fine protrusion, the melting controlled when the blending condition and film of resin with high melting point and acrylic resin is film-made is crowded Condition is very important out.

Although raw material used in the surface layer of biaxially oriented polypropylene film of the invention is by resin with high melting point and polypropylene tree Rouge is blended, but is preferably kneaded and is granulated with biaxial extruder in advance.From the viewpoint of dispersing uniformity, at this time mixed Refining temperature is preferably higher than the fusing point of resin with high melting point, more preferably high 10 DEG C or more, further preferably high 20 DEG C or more.It is being kneaded temperature In the case where fusing point of the degree lower than resin with high melting point, dispersibility is reduced sometimes, and protrusion becomes thick.The upper limit of melting temperature does not have In the case where excessively high the thermal decomposition of acrylic resin occurs sometimes for special provision, and 280 DEG C are the upper limit.

Extrusion temperature when biaxially oriented polypropylene film preferred molten of the invention squeezes out be the fusing point of resin with high melting point with Under.More preferably 10 DEG C of resin with high melting point fusing point is hereinafter, further preferably 20 DEG C of resin with high melting point fusing point or less.In high-melting-point In the case where carrying out melting extrusion at a temperature of more than the fusing point of resin, fine uniform structure is dispersed in acrylic resin sometimes Resin with high melting point melting, merges coarsening, or shear flow when by extrusion is stretched long.As a result, film table sometimes The protrusion in face becomes coarse, long side is more than 10 μm.The lower limit of melting temperature does not have special provision, but in the case where too low, has The non-fusant of filtering pressure rising, acrylic resin when Shi Fasheng is squeezed out, 200 DEG C are lower limit.

In pp material used in biaxially oriented polypropylene film of the invention, in the model for not damaging the purpose of the present invention It encloses, various additives such as crystallization nucleating agent, antioxidant, heat stabilizer, antiseize paste, antistatic agent, anti-sticking can also be contained Even agent, filler, viscosity modifier, coloring agent etc..

Wherein, the selection of the type of antioxidant and additive amount is important from the viewpoint of the exudation of antioxidant. That is, as such antioxidant, it is however preferred to have the antioxidant of the phenol system of sterically hindered property, and therein at least one kind of be The antioxidant of the high molecular weight type of 500 or more molecular weight.As its concrete example, various examples can be enumerated, preferably for example with 2,6- di-t-butyl-paracresol (BHT: molecular weight 220.4) is together and with three (bis--uncle of 3,5- of 1,3,5- trimethyl -2,4,6- Butyl -4- hydroxybenzyl) benzene (such as BASF society system " Irganox " (registered trademark) 1330: molecular weight 775.2) or four [methylenes Base -3 (3,5- di-t-butyl -4- hydroxy phenyl) propionic ester] methane (such as BASF society system " Irganox " (registered trademark) 1010: molecular weight 1177.7) etc..The total content of these antioxidants is preferably 0.03~1.0 relative to pp material total amount The range of quality %.Polymer deterioratoin and film coloring or long-term heat resistance in extrusion operation sometimes if antioxidant is excessively few Difference.If antioxidant excessively if sometimes through the exudation of these antioxidants and the transparency reduce.Preferred content is 0.05~0.9 mass %, particularly preferably 0.1~0.8 mass %.

In pp material used in biaxially oriented polypropylene film of the invention, in the model without prejudice to the purpose of the present invention In enclosing, crystallization nucleating agent can be added.As described above, branched polypropylene (H) itself has had α brilliant or the crystallization of β crystalline substance Nucleating agent effect, but can illustrate other α crystalline substance nucleating agents (dibenzylidene sorbitol class, sodium benzoate etc.), β crystalline substance nucleating agent (1, 2-hydroxystearic acid potassium, magnesium benzoate, N, the amides based compound, quinacridone such as N '-dicyclohexyl -2,6- aphthalimide Compound etc.) etc..Wherein, the superfluous of other above-mentioned nucleating agents causes the reduction of draftability, is formed by gap when being added with It is caused the transparency, intensity reduction, therefore additive amount be preferably generally 0.5 mass % hereinafter, preferably 0.1 mass % with Under, further preferably 0.05 mass % or less.

In biaxially oriented polypropylene film of the invention, organic filler and inorganic particulate are preferably free of.Due to polypropylene with have Machine particle, the compatibility of inorganic particulate are low, so if then generating gap in stretching process sometimes for biaxially-stretched film And transparency deterioration or particle fall off and pollute process, product, therefore in the product for requiring high-quality as display member etc. Protective film, manufacture base material film is in use, it is preferred that without containing the lubricants such as organic filler, inorganic particulate.

Biaxially oriented polypropylene film of the invention is carried out biaxial stretch-formed and is obtained by using above-mentioned raw materials.It is drawn as twin shaft The method stretched, by inflation simultaneously biaxial drawing method, stenter simultaneously biaxial drawing method, gradually biaxial stretching process can for stenter It obtains, but wherein, from the aspect of control film stability, the thickness uniformity, the high rigidity of film and dimensional stability, preferably Using stenter gradually biaxial stretching process.

Next the manufacturing method of biaxially oriented polypropylene film of the invention is illustrated by taking a scheme as an example, but different Fixed limit schedules this.

Firstly, the 4-methyl-1-pentene based polymer of the pp material A of 90 mass parts and 10 mass parts are put into double In axis extruder, the melting mixing at 230~280 DEG C, more preferably 240~280 DEG C, further preferably 250~280 DEG C, Make female raw material.Female raw material of 20 mass parts and the pp material A of 80 mass parts are subjected to dry type blending and are supplied to A layers Pp material A is supplied to the single axle extruding machine of B layers (base (II)), 200 by the single axle extruding machine of (surface layer (I)) Melting extrusion is carried out at~260 DEG C, more preferably 200~230 DEG C, further preferably 200~220 DEG C.In turn, setting is utilized After the filter of the midway of polymer pipe removes foreign matter, denaturation polymer etc., using branch manifold type A layer/B layers/A layers answer T-shaped mould progress lamination is closed, is discharged on curtain coating drum, lamination non-stretched of the layer composition with A layers/B layers/A layers is obtained.This When, laminated thickness is than preferably 1/8/1~1/50/1.In addition, the surface temperature of curtain coating drum is 10~40 DEG C of sights from the transparency Point considers to be preferred.In addition it is also possible to which 2 layer laminates for A layers/B layers are constituted.

As the adhesion method to curtain coating drum, the closely sealed side that electrostatic applies method, the surface tension that water is utilized can be used Method, air knife method, pressure roller method, method either among the tape casting etc. in water, but preferably flatness is good and being capable of control table The air knife method of surface roughness.The air themperature of air knife is 0~50 DEG C, and preferably 0~30 DEG C, blow out air speed is preferably 130 ~150m/s.In addition, in order not to which vibration of membrane occurs, preferably by the appropriate adjustment air knife in a manner of being film-made downstream side ventilating air Position.

In addition, making the non-curtain coating drum surface of film further force to cool down by after closely sealed to curtain coating drum, non-streaming can be inhibited The β crystalline substance for prolonging drum surface generates, and the flatness of film, the transparency can be made to improve.Use can be used in the cooling means of non-curtain coating drum surface The air cooling of air, pressure roller method, method either among the tape casting etc. in water, but preferably device simple, surface roughness Control be easy to carry out, the good air using air of flatness is cooling.

Resulting non-stretched is directed to longitudinal stretching process.Make first in longitudinal stretching process non-stretched with it is multiple Be held in 120 DEG C more than and less than 150 DEG C, preferably 140 DEG C more than and less than 150 DEG C, further preferably 144 DEG C or more and Metallic roll contact less than 149 DEG C is preheated and is warming up to draft temperature, along length between the roller for being provided with difference After direction is stretched to 3~8 times, it is cooled to room temperature.If preheating temperature is less than 120 DEG C, if draft temperature is 150 DEG C or more, Then the orientation of film dies down sometimes, strength reduction.Furthermore if stretching ratio is less than 3 times, the orientation of film dies down sometimes, intensity drop It is low.In addition, at this point, it is preferred that the temperature of the fireballing roller in downstream side is than upstream side in the roller for being provided with difference Low 10 DEG C of the temperature of roller or more.If it is long that the protrusion that temperature difference less than 10 DEG C, is formed in film surface sometimes becomes length direction Mountain range shape, the long side for being formed by protrusion is more than 10 μm, as base material film, cover film in use, sometimes in the table of product Face transfer is concave-convex, when being used as protective film biaxially oriented polypropylene film coating adhesive layer of the invention etc., is winding The defects of generating air trapping is sometimes prone in the case where difficulty.Consider from above-mentioned viewpoint, the temperature of the roller of upstream side is preferably 120 DEG C more than and less than 150 DEG C, the temperature of the roller in downstream side is more preferably 30 DEG C more than and less than 100 DEG C.

Then longitudinal monadic stretching membrane is led stenter to hold the end of film with fixture, in 140~165 DEG C of temperature Under in the width direction cross directional stretch to 7~13 times.If draft temperature is low, film fracture sometimes or the transparency are reduced, if drawn Stretch that temperature is excessively high, then the orientation of film is weak sometimes, strength reduction.In addition, if multiplying power is high, then film is broken sometimes, if multiplying power is low, Then the orientation of film is weak sometimes, strength reduction.

Then heat treatment and relaxation processes process in fixture by width direction tense hold in the state of along width Relaxation is given with 2~20% relaxation rate in direction, while the at a temperature of heat setting spent at 100 DEG C more than and less than 160 DEG C, with Fixture is guided by 80~100 DEG C of cooling process to the outside of stenter in the state of holding width direction tension, will The fixture of film end discharges, and is cut membrane edge edge using rolling step, winding membrane product volume.

The biaxially oriented polypropylene film for operating and obtaining as described above can be in film for packaging, surface protection film, process It is used in the various uses such as film, amenities, agriculture articles, building product, medical supplies, but especially because surface smoothness It is excellent, thus can be used as surface protection film, process film, mold release film and it is preferable to use.

Next, to use biaxially oriented polypropylene film of the invention as the coating substrate (base material film) of adhesive film The example of situation is illustrated.

Bonding agent used in adhesive layer is not particularly limited, and rubber series, vinyl polymerization system, condensation polymerization can be used System, thermosetting resin system, organic silicon-type etc..Wherein, as the bonding agent of rubber series, butadiene-styrene copolymer can be enumerated Object system, hycar system, isobutylene-isoprene copolymer system etc..Bonding as vinyl polymerization system Agent can enumerate acrylic acid series, polystyrene, vinyl copolymer system, vinyl chloride vinyl acetate copolymer System etc..In addition, the bonding agent as condensation polymerization system, can enumerate Polyester.It is further used as the bonding of heat reactive resin system Agent can enumerate epoxy resin, carbamate resins system etc..

It is wherein transparent excellent, and consider weatherability, heat resistance, humidity resistance, substrate adaptation etc., then it is suitble to make Use acrylic acid series bonding agent.As the concrete example of such acrylic acid series bonding agent, then it can enumerate the comprehensive chemistry (strain) that grinds and make " SK ダイ Application " (registered trademark) 1310,1435, SK ダイ Application 1811L, SK ダイ Application 1888, SK ダイ Application 2094, SK ダイ Application 2096, SK ダイ Application 2137, SK ダイ Application 3096, SK ダイ Application 1852 etc. are as suitable example.

In addition, being preferably used together curing agent in above-mentioned acrylic acid series bonding agent.As the concrete example of curing agent, in example In the case where isocyanates, toluene di-isocyanate(TDI), 2,4- toluene di-isocyanate(TDI), 2,6- toluene diisocynate can be enumerated Ester, 1,3- benzene dimethylene diisocyanate, 1,4- xylene diisocyanate, diphenyl methane -4-4 '-diisocyanate, Diphenyl methane -2-4 '-diisocyanate, 3- Dimethyl diphenylmethane diisocyanate, hexamethylene diisocyanate, different Fo Er Ketone diisocyanate, dicyclohexyl methyl hydride -4-4 '-diisocyanate, dicyclohexyl methyl hydride -2-4 '-diisocyanate, lysine Isocyanates etc..The mixed proportion of curing agent relative to 100 mass parts of bonding agent be 0.1~10 mass parts, preferably 0.5~5 Mass parts.If being less than 0.1 mass parts, the solidification of adhesive layer is become inadequate in drying oven sometimes, generates patch back.Such as Fruit is more than 10 mass parts, then remaining curing agent is moved to substrate or gasifies at high temperature and become pollution cause sometimes.

In addition, according to the material of adherend (glass, functional membrane), can be properly added and match in acrylic acid series bonding agent Close antioxidant, ultraviolet absorbing agent, silane coupling agent, matal deactivator etc..

The thickness d for having used the preferred adhesive layer of the adhesive film of biaxially oriented polypropylene film of the invention is 1.0 μm or less.More Preferably 0.8 μm hereinafter, further preferably 0.6 μm hereinafter, further preferably 400nm or less.If the thickness d of adhesive layer More than 1.0 μm, then the back side of base material film deteriorates with the sliding property of Nian Jie layer surface and winds and become difficult sometimes.In addition, sometimes The patch back of adhesive layer occurs.So-called patch back refers to after the solution of the one side coating adhesive layer of base material film, does in drying oven It is dry, solidify and by adhesive film of the invention in the case where not across mold release film after wound into rolls, when in use by adhesive film When uncoiling, the phenomenon that a part of adhesive layer is moved to the back side of base material film.If the thickness d of adhesive layer is more than 1.0 μm, do The drying of adhesive layer in dry furnace becomes inadequate, and patch back occurs sometimes.Make adhesive layer can with a thickness of the method for above range To use well known technology, the coating thickness in the solid component concentration of the solution of adhesive layer, various coating methods can be passed through Adjustment is to control.If the thickness of adhesive layer is excessively thin, sometimes stable coating is difficult or bonding force it is too low without with adherend Bonding, therefore 0.1 μm or so is lower limit.

180 ° of peeling forces after having used the adhesive film of biaxially oriented polypropylene film of the invention to be preferably bonded with glass plate For 1N/25mm or less.Peeling force is more preferably 0.5N/25mm hereinafter, further preferably 0.2N/25mm is hereinafter, further excellent It is selected as 0.05N/25mm or less.If peeling force is more than 1N/25mm, the sometimes sliding at the back side of base material film and Nian Jie layer surface Property deteriorate and wind become difficult, occurs patch carry on the back.In order to make peeling force above range, make the composition of adhesive layer, with a thickness of rear Furthermore the range stated forms the raw material of film, the aftermentioned range of film forming condition, it is effective for controlling the surface roughness of base material film Fruit.If peeling force is less than 0.01N/25mm, sometimes with after being bonded of adherend, peeled off in conveying moderate adhesion film, Therefore lower limit is 0.01N/25mm or so.

The manufacturing method of adhesive layer will be illustrated next, but be not necessarily limited to this.

Firstly, preparing the smears of adhesive layer.The additives such as above-mentioned bonding agent, curing agent can be dissolved in by smears Solvent and use.Solvent can carry out appropriate adjustment according to the viscosity of drying temperature, smears etc. in coating machine and use, and make For concrete example, can be used selected from methanol, ethyl alcohol, isopropanol, n-butanol, the tert-butyl alcohol, ethylene glycol single methyl ether, 1- methoxyl group- 2- propyl alcohol, propylene glycol monomethyl ether, cyclohexanone, toluene, ethyl acetate, butyl acetate, isopropylacetone, methyl ethyl ketone, first Base isobutyl ketone, diacetyl acetone, at least one or more solvent in acetylacetone,2,4-pentanedione.

Solid component concentration in smears is suitably selected according to the thickness of the viscosity of smears, adhesive layer, but preferably For 5~20 mass %.

Next, above-mentioned base material film is made to be transported to coating machine, the smears of adhesive layer is coated.Here, adhesive layer is coated Face can be any face of base material film, but preferably the pre-treatments such as sided corona treatment are first passed through to coated side in advance and improved and smears Wetability.On the other hand, in order to improve release property, the pre-treatments such as sided corona treatment are not implemented at the back side of preferred substrates film.It applies Mode for cloth (coating method) is not particularly limited, and can use metal bar mode, scraper mode, intaglio plate mode, die head mode, knife Mode reverses the existing coating methods such as mode, impregnation method.However, as described above, thickness of adhibited layer is 1.0 μm hereinafter, being Film, from the viewpoint of stablizing and obtaining the coat of film, preferably intaglio plate mode, reverse mode.

Behind the smears to base material film coating adhesive layer, leads in drying oven and the solvent in smears is removed and is obtained Obtain adhesive film.Here drying temperature is suitably set according to the boiling point of the heat resistance of base material film, solvent, but preferably 60~ 170℃.If it is less than 60 DEG C, then the solidification of adhesive layer sometimes does not carry out sufficiently and generates patch back.If it exceeds 170 DEG C, then have When base material film deformation and flatness deteriorate.Furthermore drying time is preferably 15~60 seconds.If it is less than 15 seconds, then adhesive layer sometimes Solidification do not carry out sufficiently and generate patch back.If it exceeds then productivity reduction in 60 seconds, therefore be undesirable.

Adhesive film after drying is wound in the case where not being bonded mold release film etc. with its bonding plane with up- coiler, is obtained It is bonded film roll.Adhesive film of the invention is by for above-mentioned composition, so that the solidification of adhesive layer sufficiently carries out, the back side of base material film with The sliding property for being bonded layer surface is also good, therefore winding in the case where not across mold release film when no patch back, winding Fold occur the problems such as, the good bonding film roll of quality can be obtained.

As described above operate and obtain adhesive film of the invention can film for packaging, surface protection film, process film, It is used in the various uses such as amenities, agriculture articles, building product, medical supplies, but since surface smoothness is especially excellent, Therefore can be used as surface protection film, process film and it is preferable to use.

Embodiment

Hereinafter, explaining the present invention in detail by embodiment.In addition, characteristic is determined by the following method, evaluates.

(1) film thickness

It is measured using micro- thickness gauge (ア Application リ Star society system).The film for sampling 10cm square, arbitrarily carries out 5 point measurements, finds out Average value.

(2) thickness of adhesive layer

It is measured using " film thickness measuring system " the model F20 of Off ィ Le メトリ Network ス Co., Ltd..Sample 10cm square Film arbitrarily carries out 15 point measurements, finds out average value.

(3) maximum height roughness (Sz)

Measurement uses (strain) water chestnutization システ system VertScan2.0R5300GL-Lite-AC to carry out, and passes through attached parsing Shooting picture is found out surface shape using 4 fitting carry out face corrections of multinomial by software.Determination condition is as described below.Measurement The two sides of film is carried out respectively with n=3, the Sz using its average value as each face.

Manufacturer: Co., Ltd.'s water chestnutization システ system

Device name: VertScan2.0 R5300GL-Lite-AC

Determination condition: 1/2 inch of CCD camera SONY HR-57

Object lens: 5x

Intermediate lens: 0.5x

Wavelength filter: 530nm white

Mode determination: Wave

Measure software: VS-Measure Version5.5.1

Analysis software: VS-Viewer Version5.5.1

Measure region: 1.252mm × 0.939mm.

(4) number of protrusion of surface

The high film surface (asperities) of the value of maximum height roughness Sz relative to biaxially oriented polypropylene film, uses atom Force microscope (AFM) changes place and has carried out the measurement of 10 visual fields.It is placed about sample, it is vertical with the scanning direction relative to cantilever Direction (Y direction) become length direction (so-called length direction, the mobile side of film in the manufacturing process of film of sample film To) mode sample be placed in piezoelectric element be measured.About resulting image, Off-Line function is utilized After Roughness Analysis finds out the rising height of each image, count major diameter be 10 μm or less and rising height be 50~ The number of the protrusion of 200nm.Aforesaid operations are implemented with n=12, by its average value (the protrusion number of 50 μm of square) multiplied by 4 and It is set as the protrusion of surface number of every 100 μm of square.In addition, being above-mentioned protrusion relative to rising height, along protrusion about major diameter Length direction show sectional view, between 2 points intersected with the line of the height 0nm as average height line as sectional view curve Distance and read.

Measurement device: NanoScope (R) IIIa AFM

(Digital Instruments society system)

Cantilever: silicon single crystal

Scan pattern: tapping-mode

Scanning range: 50 μm

Scanning speed: 0.7978Hz

Automatic smoothing handles (Flatten Auto): 3 grades.

(5) mist degree of film

Using haze meter (electricity color industry society, Japan system, NDH-5000), film is measured 23 DEG C according to JISK7136 (2000) Under haze value (%) 3 times, use average value.

(6) number of flake

The film for cutting out into A4 editions is placed on black paper, the portion for marking the degree of transmission of light weak by visual observation under fluorescent light Point.By these parts of optical microphotograph sem observation, the part that maximum length is 50 μm or more is set as flake, counts of flake Number.Evaluation implements 8 parts with A4 sample, is converted into every 1m square.

(7) windability evaluation

In the one side of the low film surface (even surface) of the value of the maximum height roughness Sz of biaxially oriented polypropylene film, by third Olefin(e) acid system bonding agent (comprehensive to grind chemical society's system, " SK ダイ Application " (registered trademark) 1310) utilizes ethyl acetate, toluene, Methylethyl 100 mass parts of solid component relative to bonding agent are mixed with curing agent (Japanese Port リウレタ Application industry by ketone (MEK) dilution Society's system, U ロネート D-90) 2.0 mass parts smears, be coated using gravure coater, in 80 DEG C of baking oven It is 30 seconds dry, the adhesive film of thickness of adhibited layer 300nm is directly carried out (not across mold release film) to 2,000m winding, adhesive film is made Volume, passes through following benchmark evaluation.

A: fold, air trapping etc. when winding without film roll, appearance is good

B: observing small fold, air trapping in winding, then eliminates but if continuing volume

C: fold, air trapping occur, and winding is difficult.

(8) it is evaluated to the transfer of adherend

Sample the biaxially oriented polypropylene film and 40 μm of thickness of Japanese ゼオ of the square of width 100mm, length 100mm Application Co. Ltd. system " ゼオノア Off ィ Le system " (registered trademark), with the rough surface of biaxially oriented polypropylene film and " ゼオノア The mode of Off ィ Le system " contact is overlapped, it is clipped with 2 acrylic panels (width 100mm, length 100mm), applies the lotus of 2kg Weight, stands 24 hours under 23 DEG C of atmosphere.After 24 hours, the surface for observing " ゼオノア Off ィ Le system " by visual observation is (double The face that axis oriented polypropylene film connects), pass through following benchmark evaluation.

A: it is clean and tidy, it is same before loading with applying

B: weak bumps are confirmed

C: strong bumps are confirmed.

(embodiment 1)

(プライ system Port リマー (strain) system, TF850H's crystalline polypropylene (PP (a)), MFR:2.9g/10 minute inside disappear Revolve five unit composition ratios: 0.94) 90 mass parts, 4-methyl-1-pentene based polymer (Mitsui Chemicals (strain) system, MX004, fusing point: 230 DEG C) 10 mass parts by the ratio be mixed in a manner of from weigh-hatching plant to biaxial extruder carry out raw material supply, at 260 DEG C Lower carry out melting mixing is discharged to strip from die head, is cooled and solidified using 25 DEG C of sink, be cut into sheet stock shape and obtain A layers of pp material (1).

By (1) 20 mass parts of above-mentioned pp material as the pp material of surface layer (A) and above-mentioned crystallinity PP (a) 80 mass parts carry out dry type blending, are supplied to A layers of uniaxial melt extruder, will be as the polypropylene of sandwich layer (B) 100 mass parts of above-mentioned crystallinity PP (a) of raw material are supplied to B layers of uniaxial melt extruder, are melted at 220 DEG C It squeezes out, after the sintered filter ended with 20 μm removes foreign matter, using the compound T-shaped mould of the A/B/A of feed block type with 1/22/1 Thickness is discharged to the curtain coating drum for being 25 DEG C by surface temperature control than lamination, keeps it closely sealed with curtain coating drum by air knife.Then, The non-cooled drum surface for the piece for being mapped to the pressure absolutely empty gas blowout of 30 DEG C of temperature, pressure 0.3MPa on curtain coating drum is cooled down, and is obtained Non-stretched.Then, the piece is preheating to 145 DEG C using ceramic roller, along the length of film between the roller for being provided with difference Direction has carried out 4.2 times of stretchings.At this point, the temperature of the roller of upstream side is set as 140 DEG C in the roller for being provided with difference, The temperature of the fireballing roller in downstream side is set as 70 DEG C.Next it holds end fixture and imported into the stretching of stenter formula Machine is stretched to 8.0 times after preheating 3 seconds at 170 DEG C at 165 DEG C, on one side give in the width direction 10% it is loose while exist It is heat-treated at 150 DEG C, the outside of stenter is then oriented to by 100 DEG C of cooling process, the fixture of film end is released It puts, film roll is around in core, obtain 24 μm of thickness of biaxially oriented polypropylene film.The physical property of resulting film and evaluation result are shown In table 1.

(embodiment 2)

In embodiment 1, (1) 40 mass parts of pp material and above-mentioned 60 mass parts of crystallinity PP (a) are subjected to dry type The melt extruder for blending and being supplied to A layers of single shaft obtains thickness by method similarly to Example 1 in addition to this The biaxially oriented polypropylene film of 24 μm of degree.By the physical property of resulting film and evaluation result is shown in table in 1.

(embodiment 3)

In embodiment 1, (1) 10 mass parts of pp material and above-mentioned 90 mass parts of crystallinity PP (a) are subjected to dry type The melt extruder for blending and being supplied to A layers of single shaft obtains thickness by method similarly to Example 1 in addition to this The biaxially oriented polypropylene film of 24 μm of degree.By the physical property of resulting film and evaluation result is shown in table in 1.

(embodiment 4)

In example 2, in the roller of difference for being provided with longitudinal stretching, the temperature of the roller in downstream side is set as 125 DEG C, in addition to this, 24 μm of thickness of biaxially oriented polypropylene film is obtained by method similarly to Example 2.By gained Film physical property and evaluation result is shown in table in 1.

(embodiment 5)

In embodiment 1, the spiral shell of A layers of uniaxial melt extruder and B layers of uniaxial melt extruder is reduced Bar revolving speed and make 6 μm of final thickness of film, further make 20 DEG C of temperature of curtain coating drum, in addition to this, by with embodiment 1 Same method obtains 6 μm of thickness of biaxially oriented polypropylene film.By the physical property of resulting film and evaluation result is shown in table 1 In.

(embodiment 6)

In embodiment 1, make 35 DEG C of temperature of curtain coating drum, be further provided with the difference of longitudinal stretching In roller, make 143 DEG C of temperature of the roller of upstream side, in addition to this, obtains 24 μm of thickness by method similarly to Example 1 Biaxially oriented polypropylene film.By the physical property of resulting film and evaluation result is shown in table in 1.

(embodiment 7)

In embodiment 1, will as the pp material of surface layer (A) (1) 20 mass parts of above-mentioned pp material with Above-mentioned 40 mass parts of crystallinity PP (a) and voluntarily recycling 40 mass parts of PP raw material progress dry type blending, are supplied to A layers of list Above-mentioned 100 mass parts of crystallinity PP (a) are supplied to B layers as the pp material of sandwich layer (B) by the melt extruder of axis Uniaxial melt extruder, melting extrusion is carried out at 220 DEG C, in addition to this, is obtained by method similarly to Example 1 Obtained 24 μm of thickness of biaxially oriented polypropylene film.By the physical property of resulting film and evaluation result is shown in table in 1.At this point, so-called PP raw material is voluntarily recycled, indicates the raw material that the loss part that will be generated in the film of production example 1 is recycled.

(embodiment 8)

In the windability evaluation of the film of embodiment 1, make 1.2 μm of thickness of adhibited layer and take adhesive film, directly (not every Mold release film) carry out 2,000m winding, take bonding film roll.By the physical property of resulting film and evaluation result is shown in table in 1.Substrate The back side of film and the sliding property of Nian Jie layer surface are poor, produce fold.

(comparative example 1)

In embodiment 1, make (1) 100 matter of raw material pp material for being supplied to A layers of uniaxial melt extruder Amount part obtains 24 μm of thickness of biaxially oriented polypropylene film by method similarly to Example 1 in addition to this.Film surface Protrusion is not observed, and windability evaluation is degrading.By the physical property of resulting film and evaluation result is shown in table in 1.

(comparative example 2)

In embodiment 1, for being supplied to the raw material of A layers of uniaxial melt extruder, by pp material (1) 50 Mass parts carry out dry type blending with above-mentioned 50 mass parts of crystallinity PP (a) and supply, in addition to this, by similarly to Example 1 Method obtain 24 μm of thickness of biaxially oriented polypropylene film.The protrusion of film surface becomes being more than 10 μm along the direction MD and being linked to be The shape of mountain range shape, windability evaluation are degrading.By the physical property of resulting film and evaluation result is shown in table in 1.

(comparative example 3)

In embodiment 1, for being supplied to the raw material of A layers of uniaxial melt extruder, by 4-methyl-1-pentene system Polymer (Mitsui Chemicals (strain) system, MX004) 2 mass parts carry out dry type blending with above-mentioned 98 mass parts of crystallinity PP (a) and supply It gives, in addition to this, 24 μm of thickness of biaxially oriented polypropylene film is obtained by method similarly to Example 1.Film surface Protrusion becomes being more than 10 μm along the direction MD and the shape that is linked to be mountain range shape, and windability evaluation is degrading.By the physical property of resulting film With evaluation result is shown in table in 1.

(comparative example 4)

In example 2, in the roller of difference for being provided with longitudinal stretching, make the temperature of the roller in downstream side 140 DEG C, in addition to this, 24 μm of thickness of biaxially oriented polypropylene film is obtained by method similarly to Example 2.Film surface Protrusion become being more than 10 μm along the direction MD and the shape that is linked to be mountain range shape, windability evaluation are degrading.By the object of resulting film Property and evaluation result is shown in table in 1.

(comparative example 5)

In embodiment 1, make 45 DEG C of temperature of curtain coating drum, further make the temperature of the roller of the upstream side of longitudinal stretching 145 DEG C, in addition to this, 24 μm of thickness of biaxially oriented polypropylene film is obtained by method similarly to Example 1.Film surface Coarse, transfer evaluation is degrading.By the physical property of resulting film and evaluation result is shown in table in 1.

(comparative example 6)

In embodiment 1, film be film-made when, melting extrusion has been carried out at 250 DEG C, in addition to this, by with embodiment 1 Same method obtains 24 μm of thickness of biaxially oriented polypropylene film.The protrusion of film surface becomes be more than 10 μm along the direction MD and It is linked to be the shape of mountain range shape, windability evaluation is degrading.By the physical property of resulting film and evaluation result is shown in table in 1.

(comparative example 7)

In embodiment 1, crystalline polypropylene (PP (a)) (プライ system Port リマー (strain) system, TF850H, MFR: 2.9g/10 minutes, five unit composition ratio of meso: 0.94) 90 mass parts, 4-methyl-1-pentene based polymer (Mitsui Chemicals (strain) system, MX004, fusing point: 230 DEG C) 10 mass parts by the ratio be mixed in a manner of from weigh-hatching plant to biaxial extruder into The supply of row raw material is carried out melting mixing at 220 DEG C, is discharged from die head to strip, is cooled and solidified using 25 DEG C of sinks, cutting A layers of pp material (1) is obtained at sheet stock shape.In addition to this, thickness is obtained by method similarly to Example 1 The biaxially oriented polypropylene film of 24 μm of degree.The protrusion of film surface becomes being more than 10 μm along the direction MD and the shape that is linked to be mountain range shape, Windability evaluation is degrading.By the physical property of resulting film and evaluation result is shown in table in 1.

[table 1]

。

Claims

1. the maximum height roughness of the one side of biaxially oriented polypropylene film is being denoted as Sz1 by a kind of biaxially oriented polypropylene film, When the maximum height roughness of another side is denoted as Sz2, wherein Sz1≤Sz2, Sz1 be 50~500nm, at least one side with It is 10 μm or less there are long side with 5 frequencies with upper process in the area of 100 μm of square and is highly the prominent of 50~200nm It rises.

2. biaxially oriented polypropylene film according to claim 1, maximum height roughness Sz2 is 100~1000nm.

3. biaxially oriented polypropylene film according to claim 1 or 2, the value of Sz2/Sz1 is 3 or less.

4. biaxially oriented polypropylene film described in any one of claim 1 to 3, the number of flake is 20/m²Below.

5. biaxially oriented polypropylene film according to any one of claims 1 to 4, mist degree is 1% or less.

6. biaxially oriented polypropylene film according to any one of claims 1 to 5, the tree for being 180 DEG C or more containing fusing point Rouge.

7. biaxially oriented polypropylene film described according to claim 1~any one of 6 is used as the coating base of adhesive film Material.

8. a kind of adhesive film is arranged in at least one side of biaxially oriented polypropylene film according to any one of claims 1 to 7 There is adhesive layer.

9. adhesive film according to claim 8, adhesive layer with a thickness of 1.0 μm or less.

10. a kind of film roll is to wind adhesive film described in claim 8 or 9 in the case where not across mold release film 's.