WO2024202887A1 - 二軸延伸ポリプロピレンフィルム - Google Patents

二軸延伸ポリプロピレンフィルム Download PDF

Info

Publication number
WO2024202887A1
WO2024202887A1 PCT/JP2024/007479 JP2024007479W WO2024202887A1 WO 2024202887 A1 WO2024202887 A1 WO 2024202887A1 JP 2024007479 W JP2024007479 W JP 2024007479W WO 2024202887 A1 WO2024202887 A1 WO 2024202887A1
Authority
WO
WIPO (PCT)
Prior art keywords
film
biaxially oriented
oriented polypropylene
polypropylene film
resin
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/JP2024/007479
Other languages
English (en)
French (fr)
Japanese (ja)
Inventor
一馬 岡田
遼 下川床
正寿 大倉
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Toray Industries Inc
Original Assignee
Toray Industries Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Toray Industries Inc filed Critical Toray Industries Inc
Priority to JP2024515305A priority Critical patent/JP7658513B2/ja
Priority to CN202480005023.3A priority patent/CN120265688A/zh
Publication of WO2024202887A1 publication Critical patent/WO2024202887A1/ja
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C55/00—Shaping by stretching, e.g. drawing through a die; Apparatus therefor
    • B29C55/02—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets
    • B29C55/10—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets multiaxial
    • B29C55/12—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets multiaxial biaxial
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/32—Layered products comprising a layer of synthetic resin comprising polyolefins
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
    • C08J5/18—Manufacture of films or sheets

Definitions

  • the present invention relates to a biaxially oriented polypropylene film that has excellent quality and handleability in high-temperature environments and can be suitably used as an industrial material film.
  • biaxially oriented polypropylene film has excellent surface release properties and mechanical properties, it is ideally used as a release film, process film, or support film for a variety of components, including plastic products, building materials, and optical components.
  • Biaxially oriented polypropylene film generally forms a surface structure with steep protrusions known as crater protrusions. For this reason, for example, when an optical film is manufactured using biaxially oriented polypropylene film as a support, the steep protrusions may be transferred and steep recesses may be formed in the optical film. The optical film is then laminated to other components in the next process, but if these steep recesses remain as voids, optical defects will occur, making it difficult to use biaxially oriented polypropylene film as a support for high-end optical films.
  • the resin composition for obtaining the optical film is coated on the surface of the biaxially oriented polypropylene film, and then dried and cured in a high-temperature oven. Therefore, the biaxially oriented polypropylene film needs to maintain high rigidity even in a high-temperature environment.
  • it is generally necessary to use a highly crystalline polypropylene resin as the raw material for the biaxially oriented polypropylene film but it is known that when a highly crystalline polypropylene raw material is used, the aforementioned crater protrusions are likely to form on the surface. In this way, there is a trade-off between achieving high rigidity at high temperatures and suppressing the crater protrusion structure, and it has been extremely difficult to achieve both at the same time.
  • Patent Documents 1 and 2 describe examples in which a copolymer or a low-crystalline polypropylene raw material is blended with a propylene-based resin, which is the main raw material.
  • Patent Document 3 describes an example in which a crystal nucleating agent is added to improve mechanical strength at high temperatures, resulting in high crystallization.
  • the crystallinity of the substrate is likely to decrease.
  • the resulting film has low rigidity in a high-temperature environment, and there is concern that wrinkles will occur and flatness will deteriorate in a high-temperature environment, which poses a problem in terms of impairing quality and handleability in a high-temperature environment.
  • the film surface has high crystallinity and is prone to forming a steep protrusion structure.
  • the present invention aims to solve the above problems and provide a biaxially oriented polypropylene film that has excellent quality and handleability in a high-temperature environment.
  • the biaxially stretched polypropylene film of the present invention has the following configuration: That is, the biaxially stretched polypropylene film of the present invention is a biaxially stretched polypropylene film, characterized in that, when a surface having a relatively small peak actual volume Vmp and a peak actual volume Vmp of 0.1 ⁇ L/ m2 or more and 50 ⁇ L/m2 or less is defined as surface A, one surface is the surface A, and a value F5t obtained by multiplying the stress F5 value at 5% elongation in the direction perpendicular to the main orientation of the film at 130°C by the film thickness is 50 Pa ⁇ m or more and 1000 Pa ⁇ m or less.
  • the present invention makes it possible to provide a biaxially oriented polypropylene film that is excellent in quality and handling properties even in high-temperature environments.
  • FIG. 1 is a conceptual diagram showing a peak actual volume Vmp and a valley volume Vvv.
  • the biaxially stretched polypropylene film of the present invention is characterized in that, when a surface having a relatively small peak actual volume Vmp and a value between 0.1 ⁇ L/ m2 and 50 ⁇ L/ m2 is defined as surface A, one surface is the surface A, and a value F5t obtained by multiplying the stress F5 value at 5% elongation in the direction perpendicular to the main orientation of the film at 130° C. by the film thickness is 50 Pa ⁇ m or more and 1000 Pa ⁇ m or less.
  • the biaxially stretched polypropylene film of the present invention will be described in detail below.
  • the peak actual volume Vmp (hereinafter sometimes simply referred to as Vmp) is one of the surface parameters obtained from a scanning white light interference microscope. More specifically, as shown in Figure 1, the peak actual volume Vmp (symbol 1) can be expressed as the area surrounded by a load curve (symbol 2) with the vertical axis representing height and the horizontal axis representing the load area ratio, an equivalent line (symbol 3) at a load area ratio of 10%, and a position line (vertical axis) representing a load area ratio of 0%.
  • Biaxially oriented polypropylene film is prone to forming steep protrusion structures known as crater protrusions. For this reason, for example, when biaxially oriented polypropylene film is used as a support and an optical film is formed on its surface, the steep protrusions may be transferred, resulting in the formation of steep recesses in the optical film. If such recesses are transferred to the optical film, the recesses will remain as voids when the optical film is bonded to another component in the next process, which may result in optical defects.
  • Vmp which represents the volume of the protruding peaks
  • Vmp is particularly highly correlated with the steep projection structure.
  • the biaxially stretched polypropylene film of the present invention has a relatively small peak actual volume Vmp, and when the surface having a peak actual volume Vmp of 0.1 ⁇ L/m 2 or more and 50 ⁇ L/m 2 or less is defined as surface A, one surface is surface A.
  • the upper limit of Vmp on surface A is preferably 30 ⁇ L/m 2 , more preferably 10 ⁇ L/m 2.
  • Vmp being greater than 50 ⁇ L/m 2 means that many steep protrusion structures are formed on the surface of the biaxially stretched polypropylene film.
  • the lower limit of Vmp on surface A is preferably 0.3 ⁇ L/m 2 , more preferably 0.5 ⁇ L/m 2 .
  • a Vmp of less than 0.1 ⁇ L/ m2 means that the surface of the biaxially oriented polypropylene film is excessively smooth. Therefore, there is a concern that the dynamic friction coefficient of a biaxially oriented polypropylene film having such a surface increases and wrinkles are generated when the film is transported in a high-temperature environment or immediately after heating.
  • a method can be used in which the raw material composition of the biaxially oriented polypropylene film is within the range described below, and the film-forming conditions are within the range described below.
  • it is effective to use an olefin-based elastomer resin having a softening temperature within the appropriate range, which is uniformly dispersed by melt-kneading it with polypropylene resin in advance and forming chips, as the raw material for the outermost layer, and to use a polypropylene resin having a half-crystallization time and melting point within the appropriate range as the main component of the outermost layer (details will be described later).
  • the casting temperature low to optimize the crystallization rate during casting, suppress the formation of ⁇ -crystal spherulites, and form a dense spherulite structure, and to set the preheating temperature and stretching temperature during longitudinal and transverse stretching within the appropriate range described below, and precisely control the surface structure by controlling the deformation of the elastomer resin domain.
  • the value F5t obtained by multiplying the stress F5 value at 5% elongation in the direction perpendicular to the main orientation of the film at 130°C by the film thickness is 50 Pa ⁇ m or more and 1000 Pa ⁇ m or less.
  • the lower limit of F5t is preferably 100 Pa ⁇ m, more preferably 150 Pa ⁇ m.
  • F5t is less than 50 Pa ⁇ m
  • a resin composition that is a raw material for an optical film or the like is applied onto the biaxially oriented polypropylene film and then dried and cured in a high-temperature oven
  • the biaxially oriented polypropylene film will elongate in the longitudinal direction and shrink in the width direction.
  • the flatness of the biaxially oriented polypropylene film will be impaired, and there is a concern that the quality and handling property will be deteriorated.
  • the upper limit of F5t is 1000 Pa ⁇ m, preferably 400 Pa ⁇ m, and more preferably 300 Pa ⁇ m.
  • the main orientation direction here refers to the direction that shows the highest value when an arbitrary direction in the film plane is set as 0° and Young's modulus is measured in each direction that forms an angle of 0° to 165° in 15° increments with respect to the arbitrary direction.
  • the direction perpendicular to the main orientation refers to the direction perpendicular to the main orientation direction in the film plane.
  • the Young's modulus here refers to the Young's modulus calculated in accordance with the method specified in JIS K 7161 (2014) by setting a rectangular sample with a length of 150 mm (measurement direction) and a width of 10 mm with an initial chuck distance of 50 mm and conducting a tensile test at room temperature at a tensile speed of 300 mm/min. The method for measuring Young's modulus will be described in detail later.
  • the F5t of a biaxially oriented polypropylene film can be measured using the following procedure. First, the biaxially oriented polypropylene film is heated for 1 minute in an oven heated to 130°C, and then a tensile test is performed at a tensile speed of 300 mm/min to measure the load applied to the biaxially oriented polypropylene film when it is elongated by 5%. The value obtained by dividing the value by the cross-sectional area (film thickness x width) of the sample before the test is calculated as the stress at an elongation of 5%, and this is multiplied by the film thickness to measure and calculate. The measurement method will be described in detail later.
  • a method can be used in which the raw material composition of the biaxially stretched polypropylene film is set within the range described below, and the film-forming conditions are set within the range described below.
  • it is effective to optimize the crystallinity and orientation of the film by using a polypropylene resin having an appropriate melting point and molecular weight range as the main component.
  • transverse stretching is possible without significantly relaxing the orientation structure of the uniaxially stretched film after longitudinal stretching, and high mechanical strength can be maintained even at high temperatures, which is effective.
  • the dynamic friction coefficient ⁇ d of the front and back of the film after heating for 10 minutes at 130°C is 0.30 or more and 1.40 or less.
  • the upper limit of the dynamic friction coefficient ⁇ d of the front and back of the film after heating for 10 minutes at 130°C is more preferably 1.20, even more preferably 1.00, particularly preferably 0.80, and most preferably 0.75.
  • the lower limit of the dynamic friction coefficient ⁇ d of the front and back of the film after heating for 10 minutes at 130°C is not particularly limited, but is substantially about 0.30.
  • the "dynamic friction coefficient ⁇ d of the front and back of the film” is the friction coefficient measured by overlapping and rubbing different surfaces against each other, and the dynamic friction coefficient ⁇ d can be measured in accordance with JIS K 7125 (1999) (details will be described later).
  • an olefin-based elastomer resin may be uniformly dispersed to suppress the formation of crater protrusions.
  • the olefin-based elastomer may soften when heated to 130°C, resulting in an increase in the coefficient of friction between the front and back of the film, which may result in poor flatness after heating.
  • a method can be used in which the raw material composition of the biaxially oriented polypropylene film is set in the range described below, and the film-forming conditions are set in the range described below.
  • it is effective to suppress the softening of the elastomer resin when heated at 130°C by setting the softening temperature and the amount of addition of the olefin-based elastomer resin in the appropriate range.
  • the preheating temperature and stretching temperature for longitudinal stretching and transverse stretching in the appropriate range, and to perform a relaxation treatment in the longitudinal direction of the uniaxially oriented film after longitudinal stretching at a temperature range below the softening temperature of the elastomer to form a fine uneven structure on the film surface, thereby reducing the contact area between the transport roll and the film surface.
  • the biaxially stretched polypropylene film of the present invention when the surface opposite to the A surface is the B surface, preferably has 0.001 to 30 craters per mm2 of the B surface with a major axis exceeding 100 ⁇ m. If the number of craters with a major axis exceeding 100 ⁇ m is more than 30 craters per mm2 , when the biaxially stretched polypropylene film is used as a support for optical film production, the steep protrusions originating from the craters on the B surface may be transferred to the optical film when the optical film is formed on the A surface and wound up, and steep recesses may be formed in the optical film.
  • the steep recesses may remain as voids, which may cause optical defects.
  • the fewer the number of craters, the better, and the upper limit is more preferably 20 craters/ mm2 , even more preferably 10 craters/ mm2 , and most preferably 5.0 craters/ mm2 .
  • the lower limit is not particularly limited, but is substantially 0.001 pieces/ mm2 .
  • a "crater" refers to a shape having a coarse depression, specifically, a depression whose major axis is 150 nm or more when the height threshold is set to -0.1 ⁇ m.
  • the number of such craters per mm2 of surface B can be measured using a scanning white light interference microscope and an associated analysis system, and the details of the measurement method are shown in the examples.
  • a method can be used in which the raw material composition of the biaxially oriented polypropylene film is within the range described below, and the film-forming conditions are within the range described below.
  • the air temperature of the air knife it is preferable to lower the air temperature of the air knife, optimize the blown air speed, and optimize the thickness of the film, from the viewpoint of efficiently cooling the non-cooled drum surface of the sheet on the casting drum. Note that the preferred conditions for the temperature and speed of the air from the air knife will be described later.
  • the peak density Spd of side A is preferably 1.0 peaks/mm2 or more and 100 peaks/mm2 or less .
  • the peak density Spd may be simply referred to as Spd. Since the biaxially stretched polypropylene film of the present invention suppresses the formation of crater protrusions, the slipperiness is easily deteriorated, but in order to maintain good slipperiness even on such a surface and obtain a film with good flatness, it is preferable to form many fine uneven structures on the film surface.
  • the lower limit of Spd of the A side is preferably 2.0 pieces/mm 2 , more preferably 5.0 pieces/mm 2.
  • the Spd of the A side be 1.0 pieces/mm 2 or more, the slipperiness of the biaxially oriented polypropylene film is maintained, so that the occurrence of wrinkles during transportation and the associated deterioration of flatness can be reduced.
  • the upper limit of the Spd of the A side is preferably 60 pieces/mm 2 , more preferably 40 pieces/mm 2 , particularly preferably 20 pieces/mm 2 , and most preferably 17 pieces/mm 2.
  • the Spd of the A side be 100 pieces/mm 2 or less, the fineness of the uneven structure on the surface of the biaxially oriented polypropylene film is appropriately suppressed, so that when used as an industrial material film, the deterioration of handleability due to the slipperiness is reduced.
  • Spd can be measured by a scanning white light interference microscope and an associated analysis system, and the details of the measurement method are shown in the examples.
  • a method can be used in which the raw material composition of the biaxially oriented polypropylene film is within the range described below, and the film-forming conditions are within the range described below.
  • it is effective to melt-knead an olefin-based elastomer resin having a softening temperature within the appropriate range in advance to uniformly disperse it in the polypropylene resin.
  • the preheating temperature and stretching temperature for longitudinal and transverse stretching within the appropriate range, and to subject the film after longitudinal stretching to a relaxation treatment in the longitudinal direction at a temperature range below the softening temperature of the elastomer to form a fine uneven structure on the film surface, thereby reducing the contact area between the transport roll and the film surface.
  • the valley volume Vvv of the A side is preferably 2.0 ⁇ L/m 2 or more and 20 ⁇ L/m 2 or less.
  • the valley volume Vvv (hereinafter, sometimes simply referred to as Vvv) is one of the surface parameters obtained by measurement with a scanning white light interference microscope. More specifically, as shown in FIG.
  • the valley volume Vvv (symbol 4) can be expressed as a part surrounded by a load curve (symbol 2) with the vertical axis being height and the horizontal axis being the load area ratio, an equivalent line (symbol 5) at a load area ratio of 80%, and a position line (symbol 6) at a load area ratio of 100%.
  • Vvv represents the volume of the space of the protruding valley, and a small Vvv of the surface means that the surface of the biaxially oriented polypropylene film tends to have fewer coarse recessed structures.
  • Vvv can be measured by a scanning white light interference microscope and an associated analysis system, and the details of the measurement method are shown in the examples.
  • the lower limit of Vvv of surface A is more preferably 2.5 ⁇ L/m 2 , and even more preferably 3.0 ⁇ L/m 2 .
  • the biaxially oriented polypropylene film has moderate slipperiness and good handleability.
  • the upper limit of Vvv of surface A is more preferably 15 ⁇ L/m 2 , even more preferably 10 ⁇ L/m 2 , particularly preferably 7.0 ⁇ L/m 2 , and most preferably 5.0 ⁇ L/m 2 .
  • a biaxially oriented polypropylene film having a Vvv of 2.0 ⁇ L/m2 or more and 20 ⁇ L/m2 or less on side A has good handleability and smoothness, and can be suitably used, for example, as an industrial material film for producing optical films.
  • a method in which the raw material composition of the biaxially stretched polypropylene film is set to the range described below, and the film-forming conditions are set to the range described below.
  • it is effective to add an elastomer resin having a softening temperature in an appropriate range to a polypropylene resin having a crystallization speed in an appropriate range to make the spherulites formed during casting finer, to lower the temperature of the casting drum to increase the cooling efficiency during casting, to set the preheating and stretching temperature in an appropriate range, and to stretch uniformly while suppressing the formation of coarse irregularities.
  • it is effective to perform a relaxation treatment of 2.0% to less than 10%, preferably 3.0% to less than 10%, after longitudinal stretching, or to set the temperature in the preheating and stretching process during transverse stretching to a temperature higher than the softening temperature of the elastomer resin added to the film and lower than the melting point of the polypropylene resin contained most in the film, and to stretch in the width direction while maintaining the dense irregular structure formed on the uniaxially stretched film.
  • a relaxation treatment 2.0% to less than 10%, preferably 3.0% to less than 10%, after longitudinal stretching, or to set the temperature in the preheating and stretching process during transverse stretching to a temperature higher than the softening temperature of the elastomer resin added to the film and lower than the melting point of the polypropylene resin contained most in the film, and to stretch in the width direction while maintaining the dense irregular structure formed on the uniaxially stretched film.
  • the biaxially oriented polypropylene film of the present invention preferably has a thickness of 10 ⁇ m or more and 100 ⁇ m or less.
  • the lower limit of the thickness is preferably 10 ⁇ m, more preferably 15 ⁇ m.
  • the upper limit of the thickness is preferably 100 ⁇ m, more preferably 50 ⁇ m, even more preferably 40 ⁇ m, and most preferably 28 ⁇ m.
  • the thickness of the biaxially oriented polypropylene film can be adjusted by the screw rotation speed of the extruder, the thickness and width of the unstretched sheet, the film production speed, the stretching ratio, and the like.
  • the thickness of the biaxially oriented polypropylene film can be measured with a micro thickness gauge, and the detailed measurement method will be described later.
  • the biaxially oriented polypropylene film of the present invention preferably has a heat of fusion of 160°C or less in the total heat of fusion of 5% to 50% when heated from 30°C to 260°C using a differential scanning calorimeter DSC.
  • the "heat of fusion of 160°C or less in the total heat of fusion” may be referred to as the ratio of the heat of fusion of 160°C or less.
  • the ratio of the heat of fusion of 160°C or less is more preferably 45% or less, and even more preferably 40% or less.
  • the ratio of the heat of fusion of 160°C or less be 50% or less, the amount of low-melting point components that are likely to cause deformation or fusion when stored for a long period of time in an oven during heating or in a wound state is suppressed, thereby reducing the occurrence of slippage and blocking.
  • the lower limit of the ratio of the heat of fusion of 160°C or less is more preferably 8%, and even more preferably 13%.
  • the biaxially oriented polypropylene film of the present invention is mainly composed of polypropylene resin.
  • the term "main component” means a component whose proportion in the total components of the film is more than 50% by mass and not more than 100% by mass.
  • the lower limit of the proportion of polypropylene resin in the total components of the film is more preferably 70% by mass, even more preferably 80% by mass, and particularly preferably 90% by mass.
  • the biaxially oriented polypropylene film of the present invention may contain only one type of polypropylene resin, but may also contain two or more types of polypropylene resin.
  • polypropylene resin refers to a resin that contains more than 50 mol% and not more than 100 mol% of propylene units when the total structural units constituting the molecular chain of the resin are 100 mol%.
  • the biaxially oriented polypropylene film of the present invention is not particularly limited in terms of its layer structure, and can be either a single layer or a laminated structure, but from the viewpoint of satisfying different properties such as smoothness, rigidity, and handleability, it is preferable that it is composed of at least two layers, and it is particularly preferable that it has a surface layer (I) and a base layer (II).
  • the biaxially oriented polypropylene film of the present invention has a laminated structure, from the viewpoints of handleability at high temperatures and quality, it is preferable that a layer containing a polypropylene resin having a melting point of 155°C or more and 175°C or less (preferably 160°C or more and 175°C or less) and an elastomer resin having a softening temperature of 70°C or more and 150°C or less is located as the outermost layer on at least one side.
  • the surface layer (I) is the outermost layer.
  • the polypropylene resin (polypropylene resin A) suitable as the component most abundant in the polypropylene film of the present invention will be described below.
  • the weight average molecular weight Mw of polypropylene resin A is preferably 20 ⁇ 10 4 or more and 60 ⁇ 10 4 or less from the viewpoint of crystallization behavior and the value F5t obtained by multiplying the stress F5 value at 5% elongation in the direction perpendicular to the main orientation of the film at 130 ° C. by the film thickness.
  • the lower limit of Mw is more preferably 25 ⁇ 10 4 , more preferably 30 ⁇ 10 4
  • the upper limit of Mw is more preferably 45 ⁇ 10 4 , more preferably 40 ⁇ 10 4.
  • a method of adjusting the hydrogen gas concentration during polymerization, the selection of a catalyst and/or a co-catalyst, and the selection of the composition are preferably adopted.
  • the lower limit of the melting point of polypropylene resin A is preferably 155°C, more preferably 158°C, even more preferably 160°C, and particularly preferably 163°C.
  • the resulting biaxially oriented polypropylene film has excellent heat resistance, and when used as a release film or a process film for manufacturing optical films, for example, it can maintain its shape even when passing through a heat-exposed process after being bonded to an adherend, and can suppress deformation of the adherend.
  • the upper limit of the melting point of polypropylene resin A is preferably 170°C, more preferably 168°C, and even more preferably 165°C.
  • the melting point of the polypropylene resin of the present invention be 170°C or lower, the crystal formation rate is appropriately suppressed, so that the formation of a coarse uneven structure during crystallization by casting is suppressed, the smoothness of the biaxially oriented polypropylene film is improved, and it is also easy to control the dynamic friction coefficient ⁇ d of the front and back of the film after heating at 130°C for 10 minutes within a suitable range.
  • Polypropylene resin A is preferably a homopolypropylene resin, as it has excellent heat resistance, good mechanical properties and lubricity even in high-temperature environments, and provides good handling properties.
  • the polypropylene resin A is not particularly limited as long as it satisfies the above-mentioned preferred conditions, but examples of polypropylene resins that can be suitably used in the biaxially oriented polypropylene film of the present invention and are commercially available include polypropylene resins E-203GP and F113G manufactured by Prime Polymer Co., Ltd., polypropylene resins D101, FS2011DG3, and FSX20L8 manufactured by Sumitomo Chemical Co., Ltd., and polypropylene resins FY6H and FL4 manufactured by Japan Polypropylene Corporation.
  • polypropylene resin B that is most preferably contained in the outermost layer on the A-side side
  • the lower limit of the semi-crystallization time of polypropylene resin B is preferably 50 seconds, more preferably 100 seconds, even more preferably 200 seconds, particularly preferably 300 seconds, and most preferably 400 seconds.
  • the semi-crystallization time of the polypropylene resin is 50 seconds or more, crystal formation is appropriately suppressed and coarse structures are less likely to form during crystallization by casting, improving the smoothness of the biaxially oriented polypropylene film, and making it easier to control the dynamic friction coefficient ⁇ d of the front and back of the film after heating at 130°C for 10 minutes within a suitable range.
  • the upper limit of the semi-crystallization time is preferably 1500 seconds or less, more preferably 1000 seconds or less. By having a semi-crystallization time of 1500 seconds or less, crystal formation is sufficient and fine unevenness is easily formed on the film surface. Therefore, the biaxially oriented polypropylene film becomes easier to slip and has good handling properties.
  • the crystallization half time of polypropylene resin B is an index of the crystallization rate determined by isothermal crystallization measurement at 130°C using DSC.
  • the crystallization rate is determined by a combination of factors including stereoregularity, crystallinity, and molecular weight. The detailed method and device for measuring the crystallization half time of polypropylene resin are described in the Examples section below.
  • the upper limit of the melting point of polypropylene resin B is preferably 175°C, more preferably 170°C, even more preferably 168°C, and particularly preferably 165°C.
  • the lower limit of the melting point of polypropylene resin B is preferably 155°C, more preferably 158°C, and even more preferably 160°C.
  • Polypropylene resin B is not particularly limited as long as it satisfies the above-mentioned preferred conditions, but examples of polypropylene resins that can be used in the biaxially oriented polypropylene film of the present invention and are commercially available include, in addition to the polypropylene resins listed above as polypropylene resin A, polypropylene resins E-200GP, E-203GP, and Y-400GP manufactured by Prime Polymer Co., Ltd., polypropylene resin WF836DG3 manufactured by Sumitomo Chemical Co., Ltd., polypropylene resins FY6H, MA3U, and SA4L manufactured by Japan Polypropylene Co., Ltd., and polypropylene resin VS700A manufactured by Sun Allomer Co., Ltd., etc.
  • polypropylene resins that have both the characteristics that are preferably possessed by the above-mentioned polypropylene resin A and the characteristics that are preferably possessed by the polypropylene resin B. These can be suitably used for both polypropylene resins A and B, and there is no obstacle to using the same polypropylene resin as polypropylene resins A and B.
  • the biaxially stretched polypropylene film of the present invention may contain, in addition to the polypropylene resin described above, a polypropylene resin containing copolymerized components with other unsaturated hydrocarbons within a range that does not impair the effects of the invention (hereinafter, sometimes referred to as copolymerized polypropylene resin).
  • Examples of monomer components constituting the copolymerized components in the copolymerized polypropylene resin include ethylene, 1-butene, 1-pentene, 3-methylpentene-1, 3-methylbutene-1, 1-hexene, 4-methylpentene-1, 5-ethylhexene-1, 1-octene, 1-decene, 1-dodecene, vinylcyclohexene, styrene, allylbenzene, cyclopentene, norbornene, and 5-methyl-2-norbornene.
  • the copolymerization amount of the copolymerized polypropylene resin is less than 10 mol% when the total constituent units constituting the resin are 100 mol%.
  • the ethylene component content is preferably 10 mol% or less. More preferably, it is 5 mol% or less, and even more preferably, it is 3 mol% or less.
  • the resin may be prone to degradation during the extrusion process, and fish eyes may be more likely to occur in the resulting biaxially oriented polypropylene film.
  • the biaxially oriented polypropylene film of the present invention preferably contains an elastomer resin, which is a polyolefin resin different from the polypropylene resin described above.
  • the elastomer resin is preferably an olefin-based elastomer, and more preferably a propylene-based elastomer.
  • the MFR of the elastomer resin is preferably 3.0 g/10 min or more and 50 g/10 min or less, with the lower limit being more preferably 5.0 g/10 min, and the upper limit being more preferably 40 g/10 min, even more preferably 10 g/10 min, and most preferably 8.0 g/10 min.
  • the MFR can be measured in accordance with JIS K7210-1 (2014).
  • the softening temperature of the elastomer resin is preferably 70°C or higher and 150°C or lower. From the viewpoint described below, the lower limit of the softening temperature of the elastomer resin is more preferably 110°C, and even more preferably 117°C. The upper limit of the softening temperature of the elastomer resin is more preferably 140°C, even more preferably 130°C, and particularly preferably 123°C.
  • the softening temperature of the elastomer resin is 70°C or higher, the biaxially oriented polypropylene film may be blocked when stored for a long period of time in a high temperature environment in summer, for example, in a rolled state.
  • the softening temperature of the elastomer resin is 150°C or lower, it is easy to control the deformation of the elastomer resin during the stretching process, so that the formation of a fine uneven surface structure is promoted and the formation of a coarse protrusion structure can be suppressed, resulting in improved flatness and transfer suppression effect of the biaxially oriented polypropylene film.
  • the softening temperature of the elastomer resin can be measured in accordance with JIS K 7196 (1991), and the details will be described later.
  • the proportions of the polypropylene resin and the elastomer resin in the layer are as shown below.
  • the lower limit of the proportion of the polypropylene resin in the outermost layer is preferably 50% by mass, more preferably 60% by mass, even more preferably 65% by mass, and particularly preferably 70% by mass.
  • the upper limit of the proportion of the polypropylene resin in the outermost layer is preferably 99% by mass, more preferably 90% by mass, and even more preferably 80% by mass.
  • the lower limit of the proportion of the elastomer resin in the outermost layer is preferably 1% by mass, more preferably 10% by mass, and even more preferably 20% by mass.
  • the upper limit of the proportion of the elastomer resin in the outermost layer is preferably 50% by mass, more preferably 40% by mass, even more preferably 35% by mass, and particularly preferably 30% by mass. If the proportion of the elastomer resin relative to the total amount of resin components in the outermost layer on the A-side is 50% by mass or less, the loss of surface flexibility after the biaxially oriented polypropylene film is heated in an oven or the like is reduced, and blocking between the biaxially oriented polypropylene films when rolled is also reduced.
  • the proportion of the elastomer resin relative to the total amount of resin components in the outermost layer on the A-side is 1% by mass or more, it becomes easy to adjust the Vmp of the A-side and the dynamic friction coefficient ⁇ d of the front and back of the film after heating at 130°C for 10 minutes, etc., to the preferred ranges described above.
  • Elastomer resins are commonly used as raw materials for heat seal layers, and when biaxially oriented polypropylene films are heated, there is a high possibility that they will lose slipperiness or cause blocking, so it has not been common to apply elastomer resins to the outermost layer of films used as protective films or support films.
  • the biaxially oriented polypropylene film of the present invention can be used even in high temperature environments.
  • the elastomer resin can be appropriately selected with reference to the above MFR, melting point, and softening temperature.
  • Examples of commercially available elastomer resins that can be used in the biaxially oriented polypropylene film of the present invention include, but are not limited to, Mitsui Chemicals' "Toughmer” (registered trademark) "PN2060", “PN2070”, and “BL3450”, Japan Polypropylene's “Wintec” (registered trademark) "WMG30", JSR's "Dynaron” (registered trademark) "2324P", and Mitsui Chemicals' "Milastomer” (registered trademark) "8030NHS”.
  • the polypropylene resin and elastomer resin used in the biaxially oriented polypropylene film of the present invention can contain various additives, such as crystal nucleating agents, antioxidants, heat stabilizers, slipping agents, antistatic agents, antiblocking agents, fillers, viscosity modifiers, and color inhibitors, to the extent that the object of the present invention is not impaired. These additives may be added to any layer, and multiple types may be used in combination, as long as they do not impede the effects of the present invention.
  • antioxidants are sterically hindered phenols, and at least one of them is preferably a high molecular weight type with a molecular weight of 500 or more.
  • BHT 2,6-di-t-butyl-p-cresol
  • BHT molecular weight 220.4
  • 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene e.g., BASF's "Irganox” (registered trademark) 1330: molecular weight 775.2
  • tetrakis[methylene-3(3,5-di-t-butyl-4-hydroxyphenyl)propionate]methane e.g., BASF's "Irganox" (registered trademark) 1010: molecular weight 1177.7).
  • phosphorus-based antioxidants may easily bleed out onto the surface of the biaxially oriented polypropylene film.
  • Such bleed-out may induce various problems.
  • curing treatment of the uncured or semi-cured resin film may inhibit curing.
  • an electrolyte membrane or metal membrane is formed on the surface of the biaxially oriented polypropylene film, the properties of the electrolyte membrane and the quality of the metal layer may be deteriorated.
  • the content of the phosphorus-based antioxidant in the biaxially oriented polypropylene film of the present invention is preferably 100 ppm or less, more preferably 50 ppm or less, and even more preferably 10 ppm or less. From the above viewpoint, it is preferable that the phosphorus-based antioxidant is not contained in the biaxially oriented polypropylene film, and the lower limit of the content is 0 ppm.
  • phosphorus-based antioxidants include tris(2,4-di-t-butylphenyl)phosphite (e.g., BASF's "Irgafos" (registered trademark) 168: molecular weight 647).
  • the total content of these antioxidants is preferably in the range of 0.03 to 1.0 parts by mass relative to the total amount of resin. If the amount of antioxidant is too small, the polymer may deteriorate during the extrusion process, causing the film to become discolored, or the film may have poor long-term heat resistance. If the amount of antioxidant is too large, the transparency may decrease due to the antioxidants bleeding out. From the above viewpoints, the more preferable content of the antioxidant is 0.05 to 0.9 parts by mass relative to the total amount of resin, and particularly preferably 0.1 to 0.8 parts by mass.
  • a crystal nucleating agent can be added to the biaxially stretched polypropylene film of the present invention, provided that the purpose is not adversely affected.
  • Specific examples of crystal nucleating agents include ⁇ crystal nucleating agents (dibenzylidene sorbitols, sodium benzoate, etc.), ⁇ crystal nucleating agents (potassium 1,2-hydroxystearate, magnesium benzoate, amide-based compounds such as N,N'-dicyclohexyl-2,6-naphthalenedicarboxamide, quinacridone-based compounds, etc.).
  • the amount added is 0.5 parts by mass or less, preferably 0.1 parts by mass or less, and more preferably 0.05 parts by mass or less, based on the total amount of resin.
  • the biaxially oriented polypropylene film of the present invention preferably does not contain organic particles or inorganic particles.
  • the polypropylene resin that can be preferably used as the main component of the biaxially oriented polypropylene film of the present invention has low affinity with organic particles or inorganic particles, so if these particles are contained, the particles may fall off during the film-making process and contaminate the process or product.
  • coarse protrusions are formed on the surface of the biaxially oriented polypropylene film by particles with high hardness, when the film is used as a release film for optical components, the unevenness may be transferred to the resin layer of the optical components.
  • the polypropylene film of the present invention preferably does not contain organic particles or inorganic particles.
  • the biaxially oriented polypropylene film of the present invention is preferably obtained by biaxially stretching an unstretched sheet obtained using the above-mentioned resin.
  • the biaxial stretching method may be simultaneous biaxial stretching using inflation, simultaneous biaxial stretching using a tenter, or sequential biaxial stretching using a roll-type stretching machine and a tenter. Among these, it is preferable to employ sequential biaxial stretching using a roll-type stretching machine and a tenter in terms of controlling the film formation stability, thickness uniformity, high rigidity and dimensional stability of the film.
  • biaxially oriented polypropylene film of the present invention will be explained using a biaxially oriented polypropylene film with a two-type three-layer structure as an example, but the biaxially oriented polypropylene film of the present invention is not necessarily limited to this.
  • the elastomer resin or other polypropylene resin in order to improve the dispersibility of the elastomer resin or other polypropylene resin, it is preferable to melt mix the polypropylene resin and the elastomer resin (or other polypropylene resin) in any ratio as described below to form a resin composition, which is then pelletized and used.
  • the pellets of the resin composition obtained above are fed to a single-screw extruder for the surface layer (I), and polypropylene resin A is fed to a single-screw extruder for the base layer (II). Then, melt extrusion is performed at 200 to 280 ° C, more preferably 220 to 275 ° C, and even more preferably 240 to 270 ° C., respectively.
  • the mixture is laminated in a layer structure of surface layer (I) / base layer (II) / surface layer (I) with a multi-manifold type composite T-die, discharged onto a casting drum, and cooled and solidified to obtain a laminated unstretched sheet having a layer structure of surface layer (I) / base layer (II) / surface layer (I).
  • the lamination thickness ratio is preferably in the range of 1/4/1 to 1/60/1 from the viewpoint of the balance between surface properties, mechanical strength, and thermal properties.
  • polypropylene resin A and B may be the same polypropylene resin.
  • the surface temperature of the casting drum is preferably 10 to 40°C, more preferably 15 to 30°C, even more preferably 19 to 27°C, and particularly 20 to 25°C. By setting such conditions, it becomes easy to adjust the Vmp of side A to a suitable range.
  • the layer structure may be a two-layer laminate structure of surface layer (I)/base layer (II).
  • any method may be used, such as an electrostatic application method, an adhesion method using the surface tension of water, an air knife method, a press roll method, or an underwater casting method, but the air knife method, which has good flatness and allows control of surface roughness, is preferred.
  • the air temperature of the air knife is 10 to 35°C, preferably 10 to 25°C, and even more preferably 15 to 20°C, and the blowing air speed is preferably 130 to 150 m/s.
  • the surface layer (I) side is on the casting drum side.
  • the obtained laminated unstretched sheet is introduced into the longitudinal stretching process.
  • the longitudinal stretching process it is preferable to perform longitudinal stretching in two stages in the preheating process before stretching.
  • the heating temperature is preferably the softening temperature of the elastomer resin -2°C or less, more preferably the softening temperature of the elastomer resin -10°C or less, and even more preferably the softening temperature of the elastomer resin -20°C or less.
  • the heating temperature is more preferably the preheating temperature of the first half process +10°C or more, and even more preferably the preheating temperature of the first half process +20°C or more.
  • the longitudinal stretching temperature is preferably the softening temperature of the elastomer resin + 15°C or more, more preferably the softening temperature of the elastomer resin + 20°C or more, and even more preferably the softening temperature of the elastomer resin + 25°C or more.
  • the laminated unstretched sheet is stretched in the longitudinal direction between rolls with a difference in peripheral speed by 4.0 to 6.0 times, more preferably 4.5 to 5.8 times, and even more preferably 4.5 to 5.6 times or 4.8 to 5.5 times.
  • the longitudinal direction refers to the direction in which the film runs during the manufacturing process (the winding direction when wound into a roll).
  • the temperature of the relaxation treatment in the longitudinal direction is preferably equal to or lower than the softening temperature of the elastomer resin added to the film, more preferably equal to or lower than the softening temperature of the elastomer resin minus 10°C, and even more preferably equal to or lower than the softening temperature of the elastomer resin minus 20°C, from the viewpoint of controlling the uneven surface structure and good film transportability, and the relaxation rate in the longitudinal relaxation treatment is preferably 2.0% or more and less than 10%, and the lower limit of the longitudinal relaxation treatment is more preferably 3.0%, and even more preferably 5.0%.
  • the upper limit of the longitudinal relaxation treatment is more preferably 9.0%, and even more preferably 8.0%.
  • the uniaxially stretched film is then guided into a tenter with both ends in the width direction held by clips, preheated, and transversely stretched 7.0 to 12 times in the width direction.
  • the lower limit of the stretching ratio is preferably 8.0 times, more preferably 8.6 times, and even more preferably 9.0 times, from the viewpoint of uniform stretchability of the film.
  • the upper limit of the stretching ratio is more preferably 11 times, from the viewpoint of stable stretching without film rupture.
  • the width direction refers to the direction perpendicular to the longitudinal direction within the film plane.
  • the preheating temperature is preferably equal to or higher than the softening temperature of the elastomer resin added to the film and equal to or lower than the melting point of polypropylene resin A minus 15°C.
  • the lower limit of the preheating temperature is more preferably the softening temperature of the elastomer resin + 5°C, and even more preferably the softening temperature of the elastomer resin + 10°C.
  • the upper limit of the preheating temperature is more preferably the melting point of polypropylene resin A minus 20°C, and even more preferably the melting point of polypropylene resin A minus 25°C.
  • the stretching temperature is preferably at least 20°C above the softening temperature of the elastomer resin and at most the melting point of polypropylene resin A.
  • the lower limit of the stretching temperature is more preferably the softening temperature of the elastomer resin + 25°C, and even more preferably the softening temperature of the elastomer resin + 30°C.
  • the upper limit of the stretching temperature is more preferably the melting point of polypropylene resin A - 5°C, and even more preferably the melting point of polypropylene resin A - 10°C.
  • both ends of the biaxially stretched film are held taut with clips and relaxed in the width direction by a relaxation rate of 5.0 to 20%, more preferably 7.0 to 15%, and even more preferably 9.0 to 12%, while heat fixing is performed at 140°C to 180°C, more preferably 150°C to 173°C, and even more preferably 150°C to 170°C.
  • the film is passed through a cooling process at 80 to 100°C and led to the outside of the tenter, and the clips on both ends of the width direction are released.
  • the film edges are slit and the biaxially stretched polypropylene film product roll is wound up.
  • the biaxially oriented polypropylene film obtained in the above manner can be used for various industrial applications such as packaging films, cover films, process films, sanitary products, agricultural products, construction products, and medical products, but since it has particularly excellent surface smoothness, handling properties, and blocking resistance, it can be preferably used for surface protection films, support films, and release films.
  • the biaxially oriented polypropylene film of the present invention has excellent transparency, and therefore, when focusing on the use as a cover film, it can be particularly preferably used as a cover film for photocurable resins and dry photoresists.
  • a cover film refers to a film that is attached to an object such as a molded body or film and has the function of protecting the object from scratches, contamination, etc. that occur during processing or transportation.
  • a support film is a film used to laminate an object onto a film when it is difficult to form a film on the object alone due to the object itself being thin or fragile, etc.
  • a release film is a film that has high releasability and can be attached to objects such as molded bodies and films to protect them from scratches and contamination that occur during processing and transportation, and can be easily peeled off and discarded when it is time to use the film as a final product.
  • the biaxially oriented polypropylene film of the present invention has excellent quality and handleability in high-temperature environments, so it can be preferably used when forming a laminate with a metal film by subjecting the biaxially oriented polypropylene film of the present invention to sputtering or vapor deposition.
  • the biaxially oriented polypropylene film of the present invention can be made into a laminate by forming a metal film on at least one side of the film.
  • PET films are often used because of their excellent surface smoothness, mechanical strength, and heat resistance.
  • PET has high hydrophilicity due to the ester bond, and PET films contain a small amount of moisture.
  • Such a small amount of moisture can have a negative effect on sputtering and deposition processing, and the negative effect is particularly noticeable when depositing metals belonging to Group 1 or 2 of the periodic table, which are easily reactive with moisture, or compounds containing these metals.
  • the biaxially oriented polypropylene film of the present invention is particularly suitable for use in forming metal films containing metals belonging to Group 1 or 2 of the periodic table or compounds thereof, since it is possible to obtain a laminate even in cases where it is difficult to use PET films due to the presence of a small amount of moisture.
  • the metals belonging to Group 1 or 2 refer to lithium, sodium, potassium, rubidium, cesium, francium, beryllium, magnesium, calcium, strontium, barium, and radium.
  • the biaxially oriented polypropylene film of the present invention which has a low moisture content, can be used more preferably for applications in which a metal film is formed than a PET film with a high moisture content, and can also maintain good quality of the formed metal film.
  • the upper limit of the moisture content of the biaxially oriented polypropylene film of the present invention is preferably 2000 ppm, more preferably 1000 ppm, and even more preferably 500 ppm.
  • the lower limit of the moisture content is not particularly limited, but is essentially 1 ppm.
  • the moisture content of the biaxially oriented polypropylene film can be measured by the Karl Fischer method, the details of which will be described later.
  • the lower limit of the content of polyolefin resins such as polypropylene resin and propylene-based elastomer resin is preferably 90 mass%, more preferably 95 mass%, and even more preferably 97 mass%.
  • the upper limit of the content of these resins is substantially 100 mass%.
  • Polyolefin resins such as polypropylene resin and propylene-based elastomer resin are relatively highly hydrophobic, and by increasing the ratio of these, the moisture content of the biaxially oriented polypropylene film can be reduced.
  • the biaxially oriented polypropylene film of the present invention preferably contains additives other than antioxidants (e.g., antistatic agents, viscosity modifiers, color inhibitors, slip agents, etc.) in a total amount of 0 to 500 ppm or less. It is preferable to adjust the amount of antioxidants such as phosphorus-based antioxidants as described above.
  • antioxidants e.g., antistatic agents, viscosity modifiers, color inhibitors, slip agents, etc.
  • the biaxially oriented polypropylene film of the present invention has an extremely low moisture content and generates very little outgassing, and is smoother and easier to handle than existing olefin-based films, making it suitable for use in forming transparent conductive films that require stricter vacuum conditions and higher quality.
  • a transparent conductive film is a thin film made of a material that is conductive but also transmits visible light. Specific examples include an indium-tin oxide (ITO) film, a zinc oxide (ZnO) film, and a palladium film.
  • electrolyte membranes used in fuel cells, semi-solid batteries, all-solid batteries, etc. are usually manufactured in environments where temperature and humidity are strictly controlled.
  • sulfide-type electrolyte membranes generate hydrogen sulfide when they react with moisture, so the process film used in manufacturing the electrolyte membrane is required to have an extremely low moisture content.
  • the biaxially oriented polypropylene film of the present invention is preferably used for this purpose as well.
  • the biaxially oriented polypropylene film of the present invention is preferably used as a current collector because of its excellent handling properties.
  • a current collector is a foil-like laminate used in electrodes of storage batteries such as lithium ion batteries, and is usually formed by laminating a metal film on a resin film as a base material. This metal film is laminated by processing such as vapor deposition, sputtering, plating, and electroless plating.
  • the film as the base material of the current collector is required to be thin, but as the film becomes thinner, its stiffness decreases, and the handling properties during processing are greatly reduced.
  • the film in the process of laminating the metal film, the film is subjected to high heat such as radiant heat during processing, and tension is also applied in the conveying direction, so the film is required to have good handling properties.
  • the biaxially oriented polypropylene film of the present invention is preferably used as a current collector because it can be made thin and has good handling properties.
  • the biaxially oriented polypropylene film of the present invention is preferably used as a current collector because of its excellent handling properties, and the current collector is generally used as an electrode for a storage battery.
  • a storage battery is a device that stores electrical energy and converts it back to electrical energy when needed. Specific examples include lead-acid batteries, nickel-metal hydride batteries, lithium-ion batteries, NAS batteries, and redox flow batteries.
  • the captured screen was complemented (completely complemented) using the attached analysis software, surface correction was performed using a polynomial 4th order approximation, and then the surface shape was obtained by processing with a median filter (3 ⁇ 3 pixels).
  • the measurement surfaces were both sides of the biaxially stretched polypropylene film, and the measurement positions were determined in a total of 9 positions according to the following procedure, starting from the intersection of the diagonals of the biaxially stretched polypropylene film cut into a 5 cm ⁇ 5 cm square shape. Measurements were performed at each measurement position, and Vmp, Vvv, and Spd at each measurement position were obtained according to the above procedure, and the average values were adopted as Vmp, Vvv, and Spd. When there was a difference of 0.1 ⁇ L/m2 or more in Vmp between the two surfaces, the surface with the relatively smaller Vmp was designated as surface A, and the opposite surface as surface B.
  • Measurement 1 Position of the starting point Measurement 2: Position 5.0 mm to the right of the starting point Measurement 3: Position 10.0 mm to the right of the starting point Measurement 4: Position 5.0 mm below the starting point Measurement 5: Position 5.0 mm below and 5.0 mm to the right of the starting point Measurement 6: Position 5.0 mm below and 10.0 mm to the right of the starting point Measurement 7: Position 10.0 mm below the starting point Measurement 8: Position 10.0 mm below and 5.0 mm to the right of the starting point Measurement 9: Position 10.0 mm below and 10.0 mm to the right of the starting point ⁇ Measurement conditions and device configuration> Objective lens: 10x Optical tube: 1x Zoom lens: 1x Wavelength filter: 530 nm white Measurement mode: Wave Measurement software: VS-Measure 10.0.4.0 Analysis software: VS-Viewer 10.0.3.0 Measurement area: 561.1 ⁇ m x 561.5 ⁇ m Number of pixels: 1,0
  • a tensile test was performed using a tensile tester (Orientec "Tensilon" (registered trademark) UCT-100) in an atmosphere of room temperature of 23°C and relative humidity of 65%, with an initial tensile chuck distance of 50 mm and a tensile speed of 300 mm/min.
  • the load applied to the film when the sample was elongated by 2% was read and divided by the cross-sectional area of the sample before the test (film thickness x 10 mm) to obtain the stress F2 value at 2% elongation.
  • the load applied to the film when the sample was 5% elongated was read, and the value divided by the cross-sectional area of the sample before the test (film thickness x width (10 mm)) was calculated as the stress (unit: MPa) at an elongation of 5%, and the value was multiplied by the film thickness obtained in (1).
  • the measurement was performed five times for each sample, and the average value was calculated to be the F5t value (unit: Pa ⁇ m).
  • the measurement was performed in the directions perpendicular to the main orientation of the biaxially oriented polypropylene film and with different surfaces overlapping each other, that is, with the main orientation perpendicular directions overlapping and the surface of one film contacting the back surface of the other film.
  • the same measurement was performed five times for one sample, and the average value of the obtained values was calculated to be the dynamic friction coefficient ( ⁇ d) of the sample.
  • the measurement was performed on the B side of the biaxially stretched polypropylene film, and the measurement position was determined in a total of 9 positions according to the following procedure, starting from the intersection of the diagonal lines of the biaxially stretched polypropylene film cut into a 5 cm x 5 cm square shape. Measurements were performed at each measurement position, the number of particles at each measurement position was calculated according to the above procedure, and the average value was adopted. Note that the "method of determining the measurement position" and the "measurement conditions and device configuration" were the same as in the previous section (2).
  • the softening temperature was determined according to JIS K 7196 (1991) using the following equipment and conditions. Using a hydraulic hot press molding machine set at 190°C, the elastomer resin was preheated for 5 minutes, press molded for 2 minutes under a pressure of 10 MPa, and then cooled at 20°C under a pressure of 10 MPa for 4 minutes to produce a sheet of a predetermined thickness, thereby obtaining a sheet sample.
  • the displacement was measured when heating at a heating rate of 5°C/min while applying a pressure of 2 kg/ cm2 to a 1 mm ⁇ probe using a thermomechanical analyzer TMASS6100 (manufactured by Hitachi High-Tech Science Corporation), and the temperature at which this reached 500 ⁇ m was used as the softening temperature.
  • the surface of the "ZEONORFILM” (registered trademark) (the surface that was in contact with the biaxially oriented polypropylene film) was visually observed and evaluated according to the following criteria. A: Clean and the same as before the load was applied. B: Weak irregularities were observed. C: Strong irregularities were observed.
  • the 500 mm wide adhesive film was unwound by 1 m, and tensions of 1 kg/m and 3 kg/m were applied uniformly and evenly across the entire film width to visually check for the presence or absence of flatness defects such as wrinkles and dents.
  • flatness evaluation was performed according to the following criteria. S: There was no poor flatness with free tension. A: Poor flatness was observed with free tension, but no poor flatness was observed with a tension of 1 kg/m width. B: Poor flatness was observed at a tension of 1 kg/m width, but no poor flatness was observed at a tension of 3 kg/m width. C: Even at a tension of 3 kg/m width, some areas were found to be poorly flat.
  • the biaxially oriented polypropylene film was cut to a size of 60 mm x 210 mm, and five sheets were stacked on an iron plate so that the A side and the B side of the film were in contact with each other. Then, an iron plate was placed on top of the five films so that a load of 1 kgf was applied, and the films were heated in an oven set at 120°C for 15 minutes. After being removed from the oven, the films were left to stand and gradually cooled to room temperature. Then, the stacked biaxially oriented polypropylene films were peeled off and evaluated according to the following criteria. A: The films did not adhere to each other. B: The films were adhered to each other, but could be peeled off without rupturing. C: Peeling was impossible, or the film broke during peeling.
  • a metal film made of magnesium oxide was formed on one surface of a biaxially oriented polypropylene film or a PET film by sputtering.
  • a magnetron sputtering device was used for sputtering, and after reducing the pressure from atmospheric pressure to 1 ⁇ 10 ⁇ 5 Torr, argon gas was introduced and sputtering was performed at 2 ⁇ 10 ⁇ 3 Torr to form a magnesium oxide film on the surface of the biaxially oriented polypropylene film or the PET film.
  • the time it took to reduce the pressure from atmospheric pressure to 1 ⁇ 10 ⁇ 5 Torr was measured, and the unevenness of the metal film surface was visually observed to evaluate the yield according to the following criteria.
  • the evaluation criteria were A as pass and B as fail.
  • Moisture Content A biaxially oriented polypropylene film or PET film sample was left for 4 hours or more in a room conditioned at 23° C. and 20% relative humidity, and then immersed for 24 hours in distilled water at 23° C. Thereafter, moisture on the surface of the sample was wiped off, and the moisture in the sample was dried and evaporated at a temperature of 150° C. using a trace moisture meter (manufactured by Mitsubishi Chemical Corporation, CA-20 model), and the moisture content was then quantified by the Karl Fischer method to calculate the moisture content.
  • All of PP1 to PP7 contained tetrakis[methylene-3(3,5-di-t-butyl-4-hydroxyphenyl)propionate]methane as an antioxidant in the range of 1000 ppm to 5000 ppm, and only PP7 further contained 3000 ppm of tris(2,4-di-t-butylphenyl)phosphite.
  • Polypropylene resin 1 manufactured by Prime Polymer Polypropylene resin 2 (PP2): manufactured by Borealis Polypropylene resin 3 (PP3): manufactured by Prime Polymer Polypropylene resin 4 (PP4): manufactured by Japan Polypropylene Polypropylene resin 5 (PP5): manufactured by Idemitsu Kosan Polypropylene resin 6 (PP6): manufactured by Japan Polypropylene, "WAYMAX” (registered trademark) MFX6 Polypropylene resin 7 (PP7): "WINTEC” (registered trademark) WFW4M, manufactured by Japan Polypropylene Corporation.
  • Elastomer resin 1 (ELA1): “Toughmer” (registered trademark) PN2060, manufactured by Mitsui Chemicals, Inc.
  • Elastomer resin 2 (ELA2): “Toughmer” (registered trademark) BL3450, manufactured by Mitsui Chemicals, Inc.
  • Elastomer resin 3 (ELA3): “Toughmer” (registered trademark) PN2070, manufactured by Mitsui Chemicals, Inc.
  • Elastomer resin 4 (ELA4): “Wintec” (registered trademark) WMG30, manufactured by Japan Polypropylene Corporation
  • Elastomer resin 5 (ELA5): “Vistamaxx” (registered trademark) 3020FL, manufactured by Exxon Mobil
  • Elastomer resin 6 (ELA6): “Welnex” (registered trademark) RFX4V, manufactured by Japan Polypropylene Corporation.
  • MFR is a value measured in accordance with JIS K7210-1 (2014).
  • Example 1 Polypropylene resin 1 (PP1) and elastomer resin 1 (ELA1) were fed from a lightweight hopper to a twin-screw extruder so that the ratio was 70:30 (mass ratio), melt-kneaded at 250 ° C, and discharged from a die in the form of a strand.
  • the discharged resin composition was cooled and solidified in a water tank at 25 ° C, and cut into chips to obtain a resin composition for the surface layer (I). Thereafter, the resin composition for the surface layer (I) was fed to a single-screw extruder, and PP1 was fed to a single-screw extruder for the base layer (II) as a raw material for the base layer (II).
  • Each resin mixture was melt-extruded at 250 ° C, and after removing foreign matter with a sintered filter with a 20 ⁇ m cut, the mixture was laminated in a feed block type A / B / A composite T die so that the thickness ratio of the surface layer (I) / base layer (II) / surface layer (I) was 1 / 50 / 1.
  • the obtained molten sheet-like material was discharged onto a casting drum whose surface temperature was controlled at 20 ° C., and was adhered to the casting drum by an air knife. Then, the sheet on the casting drum was cooled by injecting compressed air at 15 ° C.
  • the unstretched sheet was contacted with a metal roll at 95 ° C. in the first half of the preheating process, heated to 120 ° C. in the second half of the preheating process, and stretched 4.9 times in the longitudinal direction between rolls at 147 ° C. with a peripheral speed difference.
  • the sheet was subjected to a 5.5% relaxation treatment in the longitudinal direction with a metal roll heated to 95 ° C., to obtain a uniaxially stretched film.
  • the obtained uniaxially stretched film was introduced into a tenter-type stretching machine with both ends in the width direction held by clips, preheated at 137°C for 2 seconds, stretched 9.5 times in the width direction at 152°C, and heat-treated at 155°C while giving 10% relaxation in the width direction.
  • the film was guided to the outside of the tenter, the clips at both ends in the width direction of the film were released, and the film was wound up on a core to obtain a biaxially stretched polypropylene film with a thickness of 25 ⁇ m.
  • Table 3 The physical properties and evaluation results of the obtained film are shown in Table 3.
  • Examples 2 to 5 Comparative Examples 1 to 4
  • a biaxially stretched polypropylene film was obtained in the same manner as in Example 1, except that the raw material composition of each layer and the film-forming conditions were as shown in Table 3.
  • a resin composition obtained by melt-kneading a PP resin and an elastomer resin in advance in the same manner as in Example 1 was used for the resin composition for the surface layer (I) so that the mass ratio was as shown in Table 3.
  • the thickness was adjusted by adjusting the discharge amount during extrusion and the speed of the casting drum.
  • the physical properties and evaluation results of the obtained biaxially stretched polypropylene film are shown in Table 3.
  • the biaxially oriented polypropylene of the present invention can be used for various industrial applications such as packaging films, surface protection films, release films, support films, sanitary products, agricultural products, construction products, and medical products, but because it has particularly excellent quality and handleability in high-temperature environments, it can be preferably used as a release film or support film for photocurable resins, and a release film or support film for dry film resists.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Mechanical Engineering (AREA)
  • Manufacture Of Macromolecular Shaped Articles (AREA)
  • Shaping By String And By Release Of Stress In Plastics And The Like (AREA)
PCT/JP2024/007479 2023-03-28 2024-02-29 二軸延伸ポリプロピレンフィルム Ceased WO2024202887A1 (ja)

Priority Applications (2)

Application Number Priority Date Filing Date Title
JP2024515305A JP7658513B2 (ja) 2023-03-28 2024-02-29 二軸延伸ポリプロピレンフィルム
CN202480005023.3A CN120265688A (zh) 2023-03-28 2024-02-29 双轴拉伸聚丙烯膜

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2023-050850 2023-03-28
JP2023050850 2023-03-28

Publications (1)

Publication Number Publication Date
WO2024202887A1 true WO2024202887A1 (ja) 2024-10-03

Family

ID=92905475

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2024/007479 Ceased WO2024202887A1 (ja) 2023-03-28 2024-02-29 二軸延伸ポリプロピレンフィルム

Country Status (4)

Country Link
JP (1) JP7658513B2 (https=)
CN (1) CN120265688A (https=)
TW (1) TW202449037A (https=)
WO (1) WO2024202887A1 (https=)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010184990A (ja) * 2009-02-12 2010-08-26 Toyobo Co Ltd 表面保護用ポリプロピレン系樹脂フィルムロールおよび表面保護フィルムロール
JP2015107612A (ja) * 2013-12-05 2015-06-11 王子ホールディングス株式会社 二軸延伸ポリプロピレンフィルム
WO2016051897A1 (ja) * 2014-09-30 2016-04-07 王子ホールディングス株式会社 二軸延伸ポリプロピレンフィルム
WO2018147334A1 (ja) * 2017-02-07 2018-08-16 東レ株式会社 二軸配向ポリプロピレンフィルム
WO2022075101A1 (ja) * 2020-10-05 2022-04-14 東レ株式会社 フィルム、積層体および樹脂組成物膜の製造方法

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010184990A (ja) * 2009-02-12 2010-08-26 Toyobo Co Ltd 表面保護用ポリプロピレン系樹脂フィルムロールおよび表面保護フィルムロール
JP2015107612A (ja) * 2013-12-05 2015-06-11 王子ホールディングス株式会社 二軸延伸ポリプロピレンフィルム
WO2016051897A1 (ja) * 2014-09-30 2016-04-07 王子ホールディングス株式会社 二軸延伸ポリプロピレンフィルム
WO2018147334A1 (ja) * 2017-02-07 2018-08-16 東レ株式会社 二軸配向ポリプロピレンフィルム
WO2022075101A1 (ja) * 2020-10-05 2022-04-14 東レ株式会社 フィルム、積層体および樹脂組成物膜の製造方法

Also Published As

Publication number Publication date
TW202449037A (zh) 2024-12-16
CN120265688A (zh) 2025-07-04
JPWO2024202887A1 (https=) 2024-10-03
JP7658513B2 (ja) 2025-04-08

Similar Documents

Publication Publication Date Title
TWI711539B (zh) 雙軸延伸積層聚丙烯膜
TWI773665B (zh) 雙軸配向聚丙烯膜
TWI793097B (zh) 雙軸配向聚丙烯系膜以及積層體
CN112888729B (zh) 聚丙烯膜及脱模膜
CN110023086A (zh) 叠层聚丙烯膜
CN110248990A (zh) 双轴取向聚丙烯膜
JP2022100316A (ja) 二軸配向ポリプロピレンフィルム
EP4186689A1 (en) Laminated film
TW202302732A (zh) 聚丙烯薄膜
WO2022138531A1 (ja) ポリプロピレンフィルム、積層体、包装材、及び梱包体
JP7658513B2 (ja) 二軸延伸ポリプロピレンフィルム
KR102829668B1 (ko) 폴리올레핀 필름 및 이형용 필름
JP7355173B2 (ja) ポリオレフィンフィルム
JP2024144095A (ja) 二軸延伸ポリプロピレンフィルム
JP7691031B2 (ja) ポリプロピレンフィルム
TW202606885A (zh) 雙軸配向聚烯烴薄膜
WO2025205289A1 (ja) 二軸配向ポリオレフィンフィルム
JP2025156073A (ja) 二軸配向ポリオレフィンフィルム
JP7400851B2 (ja) ポリプロピレンフィルム、および離型用フィルム
JP2024109074A (ja) 積層体、包装材、及び梱包体
JP2025073536A (ja) ポリプロピレン系樹脂フィルム

Legal Events

Date Code Title Description
WWE Wipo information: entry into national phase

Ref document number: 2024515305

Country of ref document: JP

121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 24779026

Country of ref document: EP

Kind code of ref document: A1

WWE Wipo information: entry into national phase

Ref document number: 202480005023.3

Country of ref document: CN

WWP Wipo information: published in national office

Ref document number: 202480005023.3

Country of ref document: CN

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 24779026

Country of ref document: EP

Kind code of ref document: A1