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
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/16—Articles comprising two or more components, e.g. co-extruded layers
  • B29C48/18—Articles comprising two or more components, e.g. co-extruded layers the components being layers
• • 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
  • B29C55/14—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets multiaxial biaxial successively
• • 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
  • B29C55/28—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of blown tubular films, e.g. by inflation
• • 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
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
• • 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
  • B32B2323/00—Polyalkenes
  • B32B2323/10—Polypropylene
• • 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
  • C08J2323/00—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers
  • C08J2323/02—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers not modified by chemical after treatment
  • C08J2323/04—Homopolymers or copolymers of ethene
  • C08J2323/06—Polyethene

Definitions

• the present invention relates to a polyolefin film which is excellent in release property and quality and can be suitably used as a release film.
• Polyolefin films have excellent transparency, mechanical properties, electrical properties, etc., and are therefore used in various applications such as packaging, release, tape, electrical applications such as cable wrapping and capacitors.
• it since it has excellent surface releasability and mechanical properties, it is suitably used as a release film or process film for various members such as plastic products, building materials and optical members.
• the film is sometimes used as a cover film of a resin layer having adhesiveness such as a photosensitive resin.
• a resin layer having adhesiveness such as a photosensitive resin.
• the cover film When covering an adhesive resin layer, if the releasability of the cover film is poor, it cannot be peeled cleanly when peeled off, the shape of the resin layer that is the protective surface changes, or peeling marks remain on the protective surface There is. Therefore, a method of improving the releasability by roughening the film surface and reducing the contact area with the resin layer may be used. However, when the surface roughness of the cover film is increased, coarse protrusions are easily formed.
• the cover film when used as a release film for an optical member, surface irregularities of the film are transferred to the optical member and the product is visually recognized. In some cases, sex was affected. From the above, in order to use a release film having high required properties such as optical members, a film having both a releasability and a quality, which is uniformly and finely roughened without forming coarse projections, is required. There are cases.
• Patent Literatures 1 and 2 disclose that a crater is formed on a film surface by forming and stretching a ⁇ -crystal spherulite, which is one of the crystalline forms of polypropylene, and stretching the film. It describes an example in which the process transportability is improved. Further, Patent Document 3 describes an example in which particles are added to a film and uniaxially stretched to roughen the surface and improve process transportability. Patent Document 4 describes an example in which particles are added to the inner layer of a film and the film is stretched to roughen the surface.
• Patent Documents 1 and 2 have a problem that the surface roughness is insufficient.
• the method described in Patent Document 3 also has insufficient surface roughness.
• coarse protrusions are formed by particles having high hardness, and irregularities may be transferred to the resin layer of the optical member.
• an object of the present invention is to solve the above-mentioned problems. That is, an object of the present invention is to provide a polyolefin film having excellent releasability and quality.
• the polyolefin film of the present invention has an average roughness Sa of at least one surface (A surface) of 65 to 500 nm, a peak height Sp and a valley depth of the A surface.
• the value of Sp / Sv, which is the ratio of Sv, is 2.5 or less, and the haze of the film is 30% or less.
• the polyolefin film of the present invention can be suitably used as a release film because it has excellent release properties, heat resistance and quality.
• the polyolefin film of the present invention has an average roughness Sa of at least one side (A side) of 65 to 600 nm, and has a value of Sp / Sv which is a ratio of the peak height Sp of the A side and the valley depth Sv of the A side. 2.5 or less, and haze is 30% or less.
• the average roughness Sa of at least one surface (A surface) of the polyolefin film of the present invention is more preferably 150 to 480 nm, and further preferably 200 to 400 nm.
• a resin having a low melting point is added to the film surface layer, It is effective to roughen the film surface by partially melting the film surface by stretching at a temperature. Further, from the viewpoint of the transfer of the dents on the back surface and the transportability of the film, it is preferable that Sa is 65 to 600 nm on both surfaces of the film.
• the surface with the smaller value of Sa is defined as A surface.
• the surface having the smaller value of the peak height Sp is defined as the A surface.
• the surface with the smaller value of the valley depth Sv is defined as the A surface.
• the value of Sp / Sv which is the ratio of the peak height Sp on the A side and the valley depth Sv on the A side, is more preferably 2.0 or less, and still more preferably 1.5 or less.
• the value of Sp / Sv is an index indicating the ratio of the peak height to the valley depth.
• a low value of Sp / Sv means that the maximum in-plane height is low and the projection height of the coarse projection is low. Means Further, since the valley depth is deep and the contact area with the adherend to be bonded is reduced, it means that the releasability is enhanced.
• the value of Sp / Sv exceeds 2.5, for example, when used as a release film for an optical member, the releasability may be insufficient, or surface irregularities of the film may be transferred to the optical member, In particular, when the adherence of the adherend is strong, the adherend cannot be peeled cleanly, and the shape of the adherend surface may change or a peeling mark may remain on the adherend surface.
• the lower limit of the value of Sp / Sv is not particularly limited, but is substantially about 0.05.
• the value of Sp / Sv is 2.5 or less on both surfaces of the film.
• the raw material composition of the film is set in the range described below, and the film forming conditions are set in the range described below.
• the thickness of the surface layer, the ratio of the low melting point resin, and the stretching temperature are set.
• the haze of the polyolefin film of the invention is more preferably 20% or less, further preferably 10% or less, and most preferably 5% or less. If the haze value exceeds 30%, the transparency of the film is low, which may hinder a process inspection such as defect observation after bonding with a photosensitive resin.
• the lower limit of the haze value is not particularly limited, the lower limit is substantially about 0.1%.
• the raw material composition of the film is set in the range described below, and the film forming conditions are set in the range described later.
• the low melting point resin added to the surface layer and the polyolefin constituting the main component of the film It is effective to increase the compatibility with the resin.
• the value of Sp / Sa which is the ratio of the peak height Sp of the A surface and the average roughness Sa of the A surface, is less than 13.
• the value of Sp / Sa is an index indicating the ratio of the peak height to the average roughness.
• the fact that the value of Sp / Sa is low means that the maximum in-plane height is low and the projection height of the coarse projection is low.
• the lower limit of the value of Sp / Sa is not particularly limited, it is substantially about 0.1. Further, from the viewpoint of the transfer of the dents on the back surface and the transportability of the film, it is preferable that the value of Sp / Sa is less than 13 on both surfaces of the film. In order to make the value of Sp / Sa less than 13, the raw material composition of the film is set in the range described below, and the film forming conditions are set in the range described later, and in particular, the thickness of the surface layer and the ratio of the low melting point resin are controlled. Thus, it is effective to uniformly control the amount of resin that partially melts on the film surface.
• the polyolefin film of the present invention preferably has an elastic modulus in the thickness direction of 2.3 GPa or less. It is more preferably at most 2.0 GPa, even more preferably at most 1.8 GPa.
• the elastic modulus in the thickness direction is 2.3 GPa or less, for example, when used as a release film of an optical member, it is difficult to transfer dents even on an adherend having low hardness, which is preferable in terms of quality.
• the lower limit of the elastic modulus in the thickness direction is not particularly limited, it is substantially 0.5 GPa.
• the raw material composition of the film is set in the range described below, and the film forming conditions are set in the range described below.
• a low melting point resin is added to the surface layer to soften the surface. Is effective.
• the polyolefin film of the present invention preferably has a melting peak at 165 ° C or higher when the temperature is raised from 30 ° C to 260 ° C by differential operation calorimetry DSC.
• the temperature is more preferably 168 ° C or higher, further preferably 170 ° C or higher.
• the polyolefin film of the present invention has a melting peak at 165 ° C. or higher, for example, when used as a release film, even when passing through a step of applying high temperature heat after bonding to an adherend, the film is softened. It is preferable in terms of quality without deformation.
• the upper limit of the melting peak temperature is not particularly limited, but is substantially 180 ° C.
• the raw material composition of the film is set in the range described below, and the film forming conditions are set in the range described below.
• the film forming conditions are set in the range described below.
• the number of fish eyes is preferably 5.0 / m 2 or less. More preferably, the number is 4.0 / m 2 or less, still more preferably 3.0 / m 2 or less.
• the number of fish eyes is 5.0 / m 2 or less, a decrease in yield can be suppressed when used as a protective film or a base film for production of products requiring high quality such as display members, and the quality and productivity can be reduced. It is preferred in that respect.
• the smaller the number of fish eyes, the better, and the lower limit is 0 / m 2 .
• the composition and adjustment method of the raw materials and the lamination structure of the film are set within the ranges described later, and the additive components in the raw materials and the heat deterioration cause the It is effective to reduce the amount of resin used which causes the above. Further, it is effective to set the conditions at the time of film formation within the range described later, to remove foreign substances by filtration and to reduce the stagnation portion of the resin before the raw material is melted and formed into a sheet.
• the sum of the thermal shrinkage in the main shrinkage direction and the direction perpendicular to the main shrinkage at 150 ° C. for 15 minutes is preferably 8.0% or less, more preferably 6.0% or less. More preferably, it is 4.0% or less.
• the main shrinkage direction in the present invention is 15 °, 30 °, 45 °, 60 °, 75 °, 90 ° with respect to the arbitrary direction when the arbitrary direction is 0 ° in the film plane. , 105 °, 120 °, 135 °, 150 °, and 165 °, the directions showing the highest values when the thermal shrinkage is measured in each direction.
• a direction parallel to the direction in which the film is formed is referred to as a film forming direction, a longitudinal direction, or an MD direction, and a direction perpendicular to the film forming direction in the film plane is referred to as a width direction or a TD direction.
• the lower limit of the heat shrinkage is not particularly limited, but the film may expand in some cases, and the lower limit is substantially about -2.0%.
• the raw material composition of the film is in the range described later, and the film forming conditions are in the range described later, and particularly, a high melting point resin is used for the inner layer of the film. Also, it is effective to set the heat setting and relaxation conditions after biaxial stretching to the ranges described below.
• the polyolefin film of the present invention preferably has a maximum point strength in the direction orthogonal to the main shrinkage direction at 130 ° C of 70 MPa or more, more preferably 75 MPa or more, and even more preferably 80 MPa or more.
• the maximum point strength in the direction orthogonal to the main shrinkage direction is less than 70 MPa, for example, the film may be broken when the film is transported in a process involving heat.
• the upper limit of the breaking strength is not particularly limited, it is substantially about 200 MPa. In order to set the maximum point strength in the direction perpendicular to the main shrinkage direction at 70 ° C.
• the raw material composition of the film is set in the range described below, and the film forming conditions are set in the range described below. It is effective to use a resin having a high melting point, and to set the stretching conditions during biaxial stretching, and the heat setting and relaxation conditions after stretching within the ranges described below.
• the thickness of the polyolefin film of the present invention is appropriately adjusted depending on the application and is not particularly limited, but is preferably 0.5 ⁇ m or more and 100 ⁇ m or less from the viewpoint of handleability.
• the thickness of the film is more preferably 1 ⁇ m or more and 40 ⁇ m or less, further preferably 1 ⁇ m or more and 30 ⁇ m or less, and particularly preferably 1 ⁇ m or more and 15 ⁇ m or less.
• the thickness can be adjusted by the screw speed of the extruder, the width of the unstretched sheet, the film-forming speed, the stretching ratio, and the like, as long as the other physical properties are not reduced.
• the polyolefin film of the present invention has a laminated structure composed of at least a surface layer and an inner layer, and a polypropylene resin having a melting point of 50 ° C or more and 135 ° C or less (hereinafter, a polypropylene resin having a melting point of 50 ° C or more and 135 ° C or less).
• a polypropylene resin having a melting point of 50 ° C or more and 135 ° C or less Is also referred to as polypropylene raw material I). More preferably, it contains a polypropylene resin having a temperature of 60 ° C to 130 ° C, more preferably 60 ° C to 120 ° C, and most preferably 60 ° C to 100 ° C.
• the melting point of the polypropylene raw material I is preferably 50 ° C. or higher from the viewpoint of preventing the film surface from melting and sticking to the roll when transporting the preheating / stretching roll. From the viewpoint of partially melting and roughening the film surface during stretching, the melting point of the polypropylene raw material I is preferably 135 ° C. or lower.
• the content of the polypropylene raw material I is preferably 10% by mass or more and 80% by mass or less, and more preferably 20% by mass or more and 70% by mass or less, when the surface layer containing the polypropylene raw material I is 100% by mass. More preferably, the content is 30% by mass or more and 60% by mass or less.
• the polypropylene raw material I is preferably a homopolypropylene resin. That is, the polyolefin film of the present invention preferably contains a homopolypropylene resin as the above-mentioned polypropylene resin having a melting point of 50 ° C to 135 ° C.
• a monomer component such as ethylene may cause fisheye.
• the homopolypropylene resin preferably used as the polypropylene raw material I contained in at least one surface layer is preferably a homopolymer of propylene and produced using a metallocene catalyst as a polymerization catalyst.
• the weight average molecular weight of the homopolypropylene resin is preferably 40,000 to 200,000 (Mw: weight average molecular weight, Mn: number average molecular weight).
• Mw weight average molecular weight
• Mn number average molecular weight
• a commercially available product such as "Elmodu” manufactured by Idemitsu Kosan Co., Ltd., which is a low stereoregularity polypropylene resin, can be appropriately selected and used.
• the polyolefin film of the present invention may have a single-layer structure.
• the main component of the polyolefin film of the present invention having a single-layer structure and the main component of the inner layer of the polyolefin film of the present invention having a laminated structure are polyolefin resin (hereinafter, polyolefin resin as the main component of the inner layer of the polyolefin film, polyolefin raw material II). Is also preferred).
• the “main component” means that a specific component accounts for 50% by mass or more and 100% by mass or less, more preferably 90% by mass or more and 100% by mass or less, more preferably. Is from 95% by mass to 100% by mass, even more preferably from 96% by mass to 100% by mass, particularly preferably from 97% by mass to 100% by mass, most preferably from 98% by mass to 100% by mass.
• the polyolefin raw material II used for the polyolefin film of the present invention is preferably a polypropylene raw material from the viewpoint of strength and heat resistance, and among them, homopolypropylene is preferably used.
• the polyolefin raw material II preferably has a melting point of 155 ° C or higher, more preferably 160 ° C or higher, and still more preferably 165 ° C or higher.
• the melting point is less than 155 ° C.
• the heat resistance is poor.
• the film softens when passing through a step of applying heat after bonding to an adherend, and the direction of tension is reduced. And the adherend may be deformed.
• the polyolefin raw material II preferably has a cold xylene-soluble portion (hereinafter CXS) of 4% by mass or less and a mesopentad fraction of 0.90 or more. If these are not satisfied, the film-forming stability may be poor, the strength of the film may be reduced, and the dimensional stability and heat resistance may be significantly reduced.
• CXS cold xylene-soluble portion
• the cold xylene-soluble portion refers to a polyolefin component dissolved in xylene when a sample is completely dissolved in xylene and then precipitated at room temperature, and has low stereoregularity. It is considered that the component corresponds to a component that is difficult to crystallize due to reasons such as low molecular weight. If such components are contained in the resin in a large amount, the thermal dimensional stability of the film may be poor. Therefore, CXS is preferably 4% by mass or less, more preferably 3% by mass or less, and particularly preferably 2% by mass or less. The lower the CXS, the better, but the lower limit is about 0.1% by mass. In order to obtain such CXS, a method of increasing the catalytic activity in obtaining the resin, and a method of washing the obtained resin with a solvent or the olefin monomer itself can be used.
• the mesopentad fraction is preferably 0.90 or more, more preferably 0.94 or more.
• the mesopentad fraction is an index indicating the stereoregularity of the crystal phase of polypropylene measured by a nuclear magnetic resonance method (NMR method). The higher the numerical value, the higher the crystallinity, the higher the melting point, and the This is preferable because dimensional stability is increased.
• the upper limit of the mesopentad fraction is not particularly specified.
• a method of washing the obtained resin powder with a solvent such as n-heptane, a method of appropriately selecting a catalyst and / or a cocatalyst, and a method of appropriately selecting a composition can be used. It is preferably adopted.
• the polyolefin raw material II more preferably has a melt flow rate (MFR) of 1 to 10 g / 10 min (at 230 ° C. and a load of 21.18 N), more preferably 1 to 8 g / 10 min (at 230 ° C. and 21.18 N). Load), and particularly preferably in the range of 2 to 5 g / 10 min (230 ° C., 21.18 N load) from the viewpoint of film forming properties and film strength.
• MFR melt flow rate
• a method of controlling the average molecular weight and the molecular weight distribution of the polyolefin raw material II is adopted.
• the polyolefin raw material II may contain other unsaturated hydrocarbon copolymerization components or the like, or may be blended with a polymer, as long as the object of the present invention is not impaired.
• copolymer components and monomer components constituting the blend include ethylene, propylene (in the case of a copolymerized blend), 1-butene, 1-pentene, 3-methylpentene-1, and 3-methylbutene.
• the copolymerization amount or the blend amount is preferably less than 1 mol% in the copolymerization amount and less than 10 mass% in the blend amount.
• the content of the ethylene component contained in the polyolefin raw material II is preferably 10% by mass or less. It is more preferably at most 5% by mass, further preferably at most 3% by mass.
• the higher the content of the ethylene component the lower the crystallinity and the easier it is to improve the transparency.
• the content of the ethylene component exceeds 10% by mass, the strength is reduced, or the heat resistance is reduced and the heat is reduced. The shrinkage may be deteriorated.
• the resin tends to deteriorate during the extrusion process, and fish eyes in the film may easily occur.
• the content of the polypropylene polymer contained in the polymer constituting the film is preferably 95% by mass or more from the viewpoint of transparency and heat resistance. It is more preferably at least 96 mass%, further preferably at least 97 mass%, particularly preferably at least 98 mass%.
• the surface layer of the polyolefin film of the present invention preferably has a polyethylene raw material content of less than 3%. More preferably less than 2%, even more preferably less than 1%, and most preferably less than 0.5%.
• a matted rough polyolefin film often forms a roughened surface by blending a polypropylene raw material and a polyethylene raw material.
• this method is not preferred because the quality may be deteriorated, for example, the number of fish eyes due to polyethylene may increase, and the number of foreign substances may increase due to the shaving of the film surface.
• the polyolefin film of the present invention has a two-layer structure, it is preferable that at least one surface layer contains a low-viscosity polyolefin raw material III.
• the lower limit of the MFR is preferably 5 g / 10 min (230 ° C., 21.18 N load) or more, more preferably 6 g / 10 min or more, and still more preferably 10 g / 10 min or more.
• the upper limit of the MFR is preferably 60 g / 10 minutes or less, more preferably 30 g / 10 minutes or less.
• various additives such as a crystal nucleating agent, an antioxidant, a heat stabilizer, a slipping agent, an antistatic agent, an antiblocking agent, a filler, and a viscosity are used as long as the object of the present invention is not impaired.
• An adjusting agent, an anti-coloring agent and the like can be added.
• the selection of the type and amount of the antioxidant is important from the viewpoint of bleeding out of the antioxidant.
• a phenolic compound having steric hindrance is preferable.
• at least one of them is preferably a high molecular weight type having a molecular weight of 500 or more. Specific examples thereof include various ones.
• 1,3,5-trimethyl-2,4,6- Tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene eg, “Irganox” (registered trademark) 1330, manufactured by BASF; molecular weight 775.2
• tetrakis [methylene-3 (3,5-di- [t-butyl-4-hydroxyphenyl) propionate] methane eg, “Irganox” (registered trademark) 1010, molecular weight 1177.7, manufactured by BASF
• Irganox registered trademark
• the total content of these antioxidants is preferably in the range of 0.03 to 1.0% by mass based on the total amount of the polyolefin raw material. If the amount of the antioxidant is too small, the polymer may be deteriorated in the extrusion step, and the film may be colored, or the long-term heat resistance may be poor. If the amount of the antioxidant is too large, transparency may decrease due to bleed out of the antioxidant.
• a more preferred content is 0.05 to 0.9% by mass, particularly preferably 0.1 to 0.8% by mass.
• a crystal nucleating agent can be added to the polyolefin raw material I and the polyolefin II used for the polyolefin film of the present invention within a range not inconsistent with the object of the present invention. Further, it may contain a branched polypropylene having the effect of a crystal nucleating agent of ⁇ -crystal or ⁇ -crystal by itself, but other kinds of ⁇ -crystal nucleating agents (dibenzylidene sorbitols, sodium benzoate, etc.), ⁇ -crystal nuclei Agents (potassium 1,2-hydroxystearate, magnesium benzoate, amide compounds such as N, N'-dicyclohexyl-2,6-naphthalenedicarboxamide, quinacridone compounds, etc.) and the like.
• the addition amount is usually 0.5% by mass or less, preferably 0.1 mass% or less, more preferably 0.05 mass% or less.
• the polyolefin film of the present invention preferably does not contain organic particles and inorganic particles.
• Polypropylene used for the polyolefin film of the present invention has a low affinity for organic particles and inorganic particles, so when particles fall off and contaminate the process or product, or by particles having high hardness, coarse protrusions are formed, There is a case where irregularities are transferred to the resin layer of the optical member, and when used as a protective film or a base film for production of a product requiring high quality such as a display member, it may not contain a lubricant such as organic particles or inorganic particles. preferable.
• the polyolefin film of the present invention is preferably biaxially stretched using the above-mentioned raw materials.
• the biaxial stretching method can be obtained by any of inflation simultaneous biaxial stretching method, stenter simultaneous biaxial stretching method, and stenter sequential biaxial stretching method, and among them, film forming stability, thickness uniformity, From the viewpoint of controlling high rigidity and dimensional stability, it is preferable to employ a stenter sequential biaxial stretching method.
• polypropylene raw material I and 50 parts by mass of the polyolefin raw material II are dry-blended and supplied to a single-screw extruder for layer A (surface layer), and the polyolefin raw material II is mixed with a single-screw extruder for layer B (inner layer).
• the mixture is supplied to an extruder, and melt extrusion is performed at 200 to 280 ° C, more preferably 220 to 280 ° C, and still more preferably 240 to 270 ° C.
• the layers are laminated by a multi-manifold type A layer / B layer / A layer composite T die and discharged onto a casting drum.
• a laminated unstretched sheet having a layer configuration of layer / layer B / layer A is obtained.
• the lamination thickness ratio is preferably in the range of 1/8/1 to 1/60/1.
• the casting drum has a surface temperature of 40 to 100 ° C, preferably 60 to 100 ° C, and more preferably 75 to 100 ° C. Further, a two-layer structure of A layer / B layer may be adopted. In the case of a two-layer laminated structure, the surface layer A preferably contains a polypropylene resin having a melting point of 50 ° C. or more and 135 ° C. or less.
• a method of adhering to the casting drum any of an electrostatic application method, an adhesion method using surface tension of water, an air knife method, a press roll method, an underwater casting method, and the like may be used.
• the air knife method is preferable because it has good surface roughness and can control the surface roughness.
• the air temperature of the air knife is preferably 40 to 80 ° C., and the blowing air velocity is preferably 130 to 150 m / s. Further, it is preferable to appropriately adjust the position of the air knife so that air flows downstream of the film formation so as not to cause vibration of the film.
• the obtained unstretched sheet is introduced into a longitudinal stretching step.
• the longitudinal stretching step first, the unstretched sheet is brought into contact with a plurality of metal rolls kept at 80 ° C or higher and 130 ° C or lower, preferably 90 ° C or higher and 120 ° C or lower, more preferably 100 ° C or higher and 110 ° C or lower, and preheated.
• the film is stretched 3 to 8 times in the longitudinal direction between rolls provided with a peripheral speed difference, and then cooled to room temperature.
• the stretching temperature is from 130 ° C to 160 ° C, preferably from 140 ° C to 155 ° C, more preferably from 145 ° C to 150 ° C.
• the preheating step of longitudinal stretching is carried at a low temperature and stretched at a high temperature at a stretch to form a high melting point part and a low melting point part on the surface of the uniaxially stretched film after longitudinal stretching. It becomes important. If the preheating temperature and the stretching temperature are significantly different, the film shrinks in the width direction when touching the hot stretching roll. At that time, the film shrinks non-uniformly, which may cause wrinkles in the flow direction. As a countermeasure, a ceramic roll can be used as the stretching roll. It has been found that the film becomes slippery on the ceramic roll and can be stretched without wrinkles by uniformly shrinking the film. When the stretching ratio is less than 3 times, the orientation of the film becomes weak and the strength may be reduced. Therefore, the stretching ratio is preferably 3 times or more and 6 times or less, and more preferably 4 times or more and 5.5 times or less.
• the longitudinally uniaxially stretched film is guided to a tenter, and the end of the film is gripped with a clip, preheated, and then horizontally stretched 7 to 13 times in the width direction.
• the stretching ratio of the low melting point portion is increased, and the difference in the substantial stretching ratio of the film surface is caused, so that the film surface is rough.
• the preheating and stretching temperatures are from 165 to 180 ° C, more preferably from 170 to 180 ° C, and even more preferably from 173 to 180 ° C.
• transverse stretching at an extremely high temperature can be achieved by adding a low-melting-point resin only to the surface layer of the film, with the inner layer being composed mainly of a high-melting-point resin.
• the material is heat-set at a temperature of 160 ° C. or more and less than 170 ° C. while being relaxed in the width direction at a relaxation rate of 2 to 20% while the clip is stretched and held in the width direction.
• the film is guided to the outside of the tenter through a cooling process at 80 to 100 ° C. while holding the direction in tension, the clips at the end of the film are released, the film edge is slit in the winder process, and the film product roll is wound up.
• the polyolefin film obtained as described above can be used in various applications such as a packaging film, a surface protection film, a process film, a sanitary product, an agricultural product, a building product, and a medical product. Since it is excellent, it can be preferably used as a surface protection film, a process film, and a release film.
• Measurement mode Load-unloading test
• Maximum load 0.5mN Holding time when the maximum load is reached: 1 second Loading speed, unloading speed: 0.05 mN / sec
• the polyolefin film cut into an A4 size plate was placed on black paper, and a portion having a low light transmission was visually marked under a fluorescent lamp. These portions were observed with an optical microscope, and the portions having a maximum length of 50 ⁇ m or more were judged to be fish eyes, and the number of fish eyes was counted. The evaluation was carried out for eight A4 samples, and was converted to 1 m square.
• the maximum load until the sample was broken was read, and the value obtained by dividing the cross-sectional area (film thickness ⁇ width (10 mm)) of the sample before the test was calculated as the stress at the maximum point strength. Evaluation was performed using the average value. In addition, the value measured in the above (1) was used for the film thickness used for calculating the maximum point strength.
• Example 1 As raw materials for layer A (surface layer), 60 parts by mass of polyolefin raw material II (manufactured by Prime Polymer Co., Ltd., MFR: 2.9 g / 10 min, melting point: 164 ° C.) and polypropylene raw material I (Idemitsu Kosan Co., Ltd.) And 40 parts by mass of L-modu S901, MFR: 50 g / 10 min, melting point: 80 ° C.) and supply the mixture to a single-screw single-screw extruder for a surface layer, as a raw material for a B layer (inner layer).
• the sheet on the casting drum was cooled by injecting compressed air to the uncooled drum surface of the sheet to obtain an unstretched sheet.
• the sheet was preheated to 108 ° C. using a ceramic roll, and stretched 4.5 times in the longitudinal direction of the film between 148 ° C. rolls provided with a peripheral speed difference.
• the end was gripped with a clip and introduced into a tenter-type stretching machine. After preheating at 180 ° C. for 3 seconds, the film was stretched 8.5 times at 176 ° C., and at 167 ° C. while giving 12% relaxation in the width direction.
• Example 2 As raw materials for layer A (surface layer), 50 parts by mass of polyolefin raw material II (manufactured by Prime Polymer Co., Ltd., MFR: 2.9 g / 10 min, melting point: 164 ° C.) and polypropylene raw material I (Idemitsu Kosan Co., Ltd.) And 50 parts by mass of Elmodu S901, MFR: 50 g / 10 min, melting point: 80 ° C.) and dry-blended to supply a single-screw single-screw extruder for the surface layer.
• polyolefin raw material II manufactured by Prime Polymer Co., Ltd., MFR: 2.9 g / 10 min, melting point: 164 ° C.
• polypropylene raw material I Idemitsu Kosan Co., Ltd.
• Elmodu S901 50 parts by mass of Elmodu S901, MFR: 50 g / 10 min, melting point: 80 ° C.
• the above-mentioned polyolefin raw material II is supplied to a single-screw single-screw extruder for an inner layer, melt-extruded at 260 ° C., and foreign substances are removed by a 20 ⁇ m-cut sintered filter. Then, a feed block type A / B / A composite T The layers were laminated at a thickness ratio of 1/58/1 with a die, discharged onto a casting drum whose surface temperature was controlled to 70 ° C., and brought into close contact with the casting drum with an air knife. Thereafter, the sheet on the casting drum was cooled by injecting compressed air to the uncooled drum surface of the sheet to obtain an unstretched sheet.
• the sheet was preheated to 112 ° C. using a ceramic roll, and stretched 4.5 times in the longitudinal direction of the film between rolls at 143 ° C. provided with a peripheral speed difference.
• the end was gripped with a clip and introduced into a tenter-type stretching machine. After preheating at 176 ° C. for 3 seconds, stretching was performed 9.0 times at 172 ° C., and at 160 ° C. while giving 9% relaxation in the width direction.
• Example 3 As a raw material for the layer A (surface layer), 40 parts by mass of a polyolefin raw material II (manufactured by Prime Polymer Co., Ltd., MFR: 2.9 g / 10 min, melting point: 164 ° C.), and a polypropylene raw material I (Nippon Polypropylene Co., Ltd.) And 60 parts by mass of Wellnex RFX4V, MFR: 6.0 g / 10 min, melting point: 127 ° C.), supplied to a single-screw extruder for a surface layer and supplied to a B-layer (inner layer).
• a polyolefin raw material II manufactured by Prime Polymer Co., Ltd., MFR: 2.9 g / 10 min, melting point: 164 ° C.
• a polypropylene raw material I Nippon Polypropylene Co., Ltd.
• Wellnex RFX4V MFR: 6.0 g / 10 min, melting point: 127
• the sheet on the casting drum was cooled by injecting compressed air to the uncooled drum surface of the sheet to obtain an unstretched sheet.
• the sheet was preheated to 128 ° C. using a ceramic roll, and stretched 4.1 times in the longitudinal direction of the film between 132 ° C. rolls provided with a peripheral speed difference.
• the end portion was gripped with a clip and introduced into a tenter type stretching machine. After preheating at 179 ° C. for 3 seconds, the film was stretched 8.2 times at 177 ° C., and at 168 ° C. while giving 13% relaxation in the width direction.
• Example 4 As raw materials for layer A (surface layer), 80 parts by mass of polyolefin raw material II (manufactured by Prime Polymer Co., Ltd., MFR: 2.9 g / 10 min, melting point: 164 ° C.) and polypropylene raw material I (Idemitsu Kosan Co., Ltd.) And 20 parts by mass of Elmodu S901, MFR: 50 g / 10 min, melting point: 80 ° C.), and supplied to a single-screw single-screw extruder for a surface layer, as a raw material for a B layer (inner layer).
• polyolefin raw material II manufactured by Prime Polymer Co., Ltd., MFR: 2.9 g / 10 min, melting point: 164 ° C.
• polypropylene raw material I Idemitsu Kosan Co., Ltd.
• Elmodu S901 20 parts by mass of Elmodu S901, MFR: 50 g / 10 min, melting point: 80
• the above-mentioned polyolefin raw material II is supplied to a single-screw single-screw extruder for an inner layer, melt-extruded at 260 ° C., and foreign substances are removed by a 20 ⁇ m-cut sintered filter. Then, a feed block type A / B / A composite T The layers were laminated with a die at a thickness ratio of 1/58/1, discharged onto a casting drum whose surface temperature was controlled at 95 ° C., and brought into close contact with the casting drum with an air knife. Thereafter, the sheet on the casting drum was cooled by injecting compressed air to the uncooled drum surface of the sheet to obtain an unstretched sheet.
• the sheet was preheated to 140 ° C. using a ceramic roll, and stretched 4.5 times in the longitudinal direction of the film between 140 ° C. rolls provided with a peripheral speed difference.
• the end was gripped with a clip and introduced into a tenter-type stretching machine. After preheating at 167 ° C. for 3 seconds, the film was stretched 8.0 times at 167 ° C., and at 140 ° C. while giving 9% relaxation in the width direction.
• Example 5 50 parts by mass of polyolefin raw material II (manufactured by Prime Polymer Co., Ltd., MFR: 2.9 g / 10 min, melting point: 164 ° C.), polyolefin raw material III (manufactured by Sumitomo Chemical Co., Ltd., MFR: 7.5 g / 10) Raw material is supplied from a measuring hopper to a twin-screw extruder so that 45 parts by mass of the mixture, and 5 parts by mass of a branched polypropylene resin (manufactured by Basell) are mixed at this ratio.
• a branched polypropylene resin manufactured by Basell
• the mixture was kneaded, discharged from a die in a strand form, cooled and solidified in a water bath at 25 ° C., and cut into chips to obtain a polypropylene raw material IV.
• a raw material for the layer A surface layer
• 70 parts by mass of the polyolefin raw material II and 30 parts by mass of the polypropylene raw material IV were dry-blended and supplied to a single-screw single-screw extruder for the surface layer.
• 80 parts by mass of the polypropylene raw material II and 20 parts by mass of the polyolefin raw material III are dry-blended, supplied to a single-screw uniaxial melt extruder for an inner layer, and melt-extruded at 260 ° C.
• After removing foreign matter with a sintered filter of 20 ⁇ m cut it was laminated with a feed block type A / B / A composite T die at a thickness ratio of 1/10/1, and a casting drum whose surface temperature was controlled to 98 ° C. , And compressed air was blown from an air knife to make it adhere to the casting drum to obtain an unstretched sheet. Subsequently, the sheet was preheated to 95 ° C.
• the polyolefin raw material II is supplied to a single-screw single-screw extruder for an inner layer, melt-extruded at 260 ° C., and foreign substances are removed by a 60 ⁇ m cut sintering filter. Then, a feed block type A / B / A composite is used. The layers were laminated with a T-die at a thickness ratio of 1/88/1, discharged onto a casting drum whose surface temperature was controlled at 30 ° C., and brought into close contact with the casting drum with an air knife. Thereafter, the sheet on the casting drum was cooled by injecting compressed air to the uncooled drum surface of the sheet to obtain an unstretched sheet.
• the sheet was preheated to 140 ° C. using a ceramic roll, and stretched 4.6 times in the longitudinal direction of the film between 140 ° C. rolls provided with a peripheral speed difference.
• the end was gripped with a clip and introduced into a tenter-type stretching machine. After preheating at 160 ° C. for 3 seconds, stretching was performed 8.0 times at 155 ° C., and at 120 ° C. while giving 10% relaxation in the width direction.
• a heat treatment was performed, and then the film was guided to the outside of the tenter through a cooling process at 100 ° C., a clip at an end of the film was released, and the film was wound around a core to obtain a polyolefin film having a thickness of 12 ⁇ m.
• Table 1 shows the physical properties and evaluation results of the obtained film.
• Comparative Example 2 93.3 parts by mass of polyolefin raw material II (manufactured by Prime Polymer Co., Ltd., MFR: 2.9 g / 10 min, melting point: 164 ° C.) as a raw material for layer B (inner layer), 80 mass% of calcium carbonate and polypropylene 20 6.7 parts by mass of a master raw material (manufactured by Sankyo Seiko Co., Ltd., 2480K, calcium carbonate particles: 6 ⁇ m) compounded by mass% was dry-blended and supplied to a single-screw melt extruder for an inner layer.
• a master raw material manufactured by Sankyo Seiko Co., Ltd., 2480K, calcium carbonate particles: 6 ⁇ m
• the polyolefin raw material II was supplied to a single-axis melt extruder for surface layer, melt-extruded at 240 ° C., and after removing foreign matter with a 60 ⁇ m cut sintered filter, a feed block type
• the sheets were laminated with an A / B composite T die at a thickness ratio of 8/1, and discharged onto a cast drum whose surface temperature was controlled at 30 ° C. to obtain a cast sheet.
• preheating was performed at 125 ° C. using a plurality of ceramic rolls, and the film was stretched 4.6 times in the longitudinal direction of the film between the 125 ° C. rolls.
• the end was gripped with a clip and introduced into a tenter-type stretching machine. After preheating at 165 ° C for 3 seconds, the film was stretched 8.0 times at 160 ° C. In the subsequent heat treatment step, heat treatment is performed at 160 ° C. while giving 10% relaxation in the width direction, and then guided to the outside of the tenter through a cooling step at 130 ° C., the clip at the end of the film is released, and the film is wound around a core. Then, a polyolefin film having a thickness of 19 ⁇ m was obtained. Table 1 shows the physical properties and evaluation results of the obtained film.
• the sheet was preheated to 140 ° C. using a ceramic roll, and stretched 4.6 times in the longitudinal direction of the film between 140 ° C. rolls provided with a peripheral speed difference.
• the end was gripped with a clip and introduced into a tenter type stretching machine. After preheating at 170 ° C. for 3 seconds, the film was stretched 8.0 times at 165 ° C., and at 150 ° C. while giving 10% relaxation in the width direction. Heat treatment was performed, and then the film was guided to the outside of the tenter through a cooling process at 100 ° C., the clips at the ends of the film were released, and the film was wound around a core to obtain a 25 ⁇ m-thick polyolefin film. Table 1 shows the physical properties and evaluation results of the obtained film.
• the mixture was kneaded, discharged from a die in a strand form, cooled and solidified in a water bath at 25 ° C., and cut into chips to obtain a polypropylene raw material IV.
• a raw material for the layer A surface layer
• 70 parts by mass of the polyolefin raw material II and 30 parts by mass of the polypropylene raw material IV are dry-blended and supplied to a single-screw single-screw extruder for the surface layer.
• 80 parts by weight of the polyolefin raw material II and 20 parts by weight of the polyolefin raw material III are dry-blended and supplied to a single-screw single-screw extruder for an inner layer.
• the casting drum was laminated with a feed block type A / B / A composite T die at a thickness ratio of 1/34/1, and the surface temperature was controlled to 70 ° C. , And compressed air was blown from an air knife to make it adhere to the casting drum to obtain an unstretched sheet. Subsequently, the sheet was preheated to 133 ° C. using a ceramic roll, and stretched 3.9 times in the longitudinal direction of the film between 138 ° C. rolls having different peripheral speeds. Next, the end was gripped with a clip and introduced into a tenter-type stretching machine. After preheating at 173 ° C.
• the above-mentioned polypropylene raw material V is supplied to a single-screw single-screw extruder for the surface layer, and as a raw material for the layer B (inner layer), a polyolefin raw material II (manufactured by Prime Polymer Co., Ltd.) (MFR: 2.9 g / 10 min, melting point: 164 ° C.) to a single-screw single-screw extruder for the inner layer, perform melt extrusion at 240 ° C., remove foreign matter with a 20 ⁇ m cut sintered filter, and feed Laminated at a thickness ratio of 1/34/1 using a block type A / B / A composite T die, discharges it to a casting drum whose surface temperature is controlled to 90 ° C, and blows compressed air from an air knife to the casting drum.
• a polyolefin raw material II manufactured by Prime Polymer Co., Ltd.
• the sheets were brought into close contact with each other to obtain an unstretched sheet. Subsequently, the sheet was preheated to 108 ° C. using a ceramic roll, and stretched 4.6 times in the longitudinal direction of the film between 148 ° C. rolls provided with a peripheral speed difference. Next, the end was gripped with a clip and introduced into a tenter-type stretching machine. After preheating at 180 ° C. for 3 seconds, the film was stretched 8.5 times at 176 ° C., and at 167 ° C. while giving 12% relaxation in the width direction.
• the polyolefin film of the present invention can be used in various applications such as a packaging film, a release film, a process film, a sanitary product, an agricultural product, a building product, and a medical product.
• a packaging film a release film
• a process film a sanitary product
• an agricultural product a building product
• a medical product since it is excellent in transparency and smoothness, it can be preferably used as a release film and a process film for applications requiring surface smoothness of a product, and since it has excellent release properties, the cover of the adhesive resin layer can be used. It is preferably used as a release film such as a film.

Landscapes

• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Mechanical Engineering (AREA)
• Manufacturing & Machinery (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Materials Engineering (AREA)
• Laminated Bodies (AREA)
• Manufacture Of Macromolecular Shaped Articles (AREA)

Priority Applications (3)

Applications Claiming Priority (2)

Publications (1)

Family

ID=70055161

Family Applications (1)

Country Status (5)

Citations (7)

Family Cites Families (6)

• 2019
  • 2019-09-27 WO PCT/JP2019/038364 patent/WO2020071291A1/ja active Application Filing
  • 2019-09-27 JP JP2019555044A patent/JP6753540B1/ja active Active
  • 2019-09-27 CN CN201980064163.7A patent/CN112771102A/zh active Pending
  • 2019-09-27 KR KR1020217007953A patent/KR20210069630A/ko unknown
  • 2019-10-03 TW TW108135811A patent/TWI827693B/zh active
• 2020
  • 2020-08-18 JP JP2020137991A patent/JP6962426B2/ja active Active

Patent Citations (7)

Also Published As

Similar Documents

Legal Events