Classifications

• • 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
  • B32B15/00—Layered products comprising a layer of metal
• • 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
  • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
  • B32B7/02—Physical, chemical or physicochemical properties
  • B32B7/023—Optical properties
• • 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
  • B32B15/00—Layered products comprising a layer of metal
  • B32B15/04—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material
  • B32B15/08—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
  • B32B15/09—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin comprising polyesters
• • 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
  • B32B17/00—Layered products essentially comprising sheet glass, or glass, slag, or like fibres
  • B32B17/06—Layered products essentially comprising sheet glass, or glass, slag, or like fibres comprising glass as the main or only constituent of a layer, next to another layer of a specific material
  • B32B17/061—Layered products essentially comprising sheet glass, or glass, slag, or like fibres comprising glass as the main or only constituent of a layer, next to another layer of a specific material of metal
• • 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
  • B32B27/18—Layered products comprising a layer of synthetic resin characterised by the use of special additives
  • B32B27/20—Layered products comprising a layer of synthetic resin characterised by the use of special additives using fillers, pigments, thixotroping agents
• • 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
  • B32B27/36—Layered products comprising a layer of synthetic resin comprising polyesters
• • 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
  • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
  • B32B7/04—Interconnection of layers
  • B32B7/12—Interconnection of layers using interposed adhesives or interposed materials with bonding properties
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K5/00—Casings, cabinets or drawers for electric apparatus
  • H05K5/02—Details
  • H05K5/0217—Mechanical details of casings
• • 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
  • B32B2307/00—Properties of the layers or laminate
  • B32B2307/50—Properties of the layers or laminate having particular mechanical properties
  • B32B2307/538—Roughness
• • 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
  • B32B2309/00—Parameters for the laminating or treatment process; Apparatus details
  • B32B2309/08—Dimensions, e.g. volume
  • B32B2309/10—Dimensions, e.g. volume linear, e.g. length, distance, width
  • B32B2309/105—Thickness
• • 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
  • B32B2457/00—Electrical equipment

Definitions

• the present invention relates to a polyester film, for example, a polyester film used in an application requiring a light-shielding property.
• a metal housing has been used for small electronic devices such as smartphones and personal computers.
• at least a part of the metal housing should be made of glass. Is being tried.
• a part of the housing is made of glass, it is considered to laminate a resin film having a light-shielding property on the glass in order to make the inside invisible.
• a resin film having a light-shielding property may be used.
• Patent Document 1 is characterized in that a film containing a black pigment having a surface roughness (SRa) of at least one side of the film is 100 to 150 nm and a breaking strength in the film width direction is 200 MPa or more. The film is listed.
• SRa surface roughness
• the present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to provide a polyester film having high light-shielding property, excellent surface smoothness, and a small difference in glossiness between the front and back surfaces. ..
• a polyester film comprising a polyester layer (A) containing a black pigment and a polyester layer (B) on at least one surface thereof.
• the polyester layer (B) contains substantially no particles or contains particles (X) having an average particle size of 1.0 ⁇ m or less.
• the ratio of the thickness of the polyester layer (B) to the thickness of the polyester layer (A) [thickness of (B) / thickness of (A)] is 0.025 to 0.25.
• a polyester film having high light-shielding property and excellent surface smoothness is suitable as a member for a terminal device (smartphone, I-Pad, etc.) equipped with a communication function.
• the polyester film of the present invention is a polyester film including a polyester layer (A) containing a black pigment and a polyester layer (B) on at least one surface thereof.
• the polyester layer (B) contains substantially no particles or contains particles having an average particle size of 1.0 ⁇ m or less (hereinafter, also referred to as particles (X)), and is the same as the polyester film.
• the permeation concentration (OD value) is 0.4 or more.
• Pigments may aggregate in the polyester layer (A) of the polyester film, but by providing a polyester layer (B) that does not substantially contain particles or has particles having a small average particle size as a surface layer, It is possible to prevent the surface smoothness of the polyester film from being impaired due to the aggregation of the pigment.
• the polyester film of the present invention has a high light-shielding property because it has a transmission concentration of 0.4 or more by containing a large amount of pigment, and when used for a housing of an electronic device, the inside of the housing has a high light-shielding property. The design is improved because it cannot be seen through.
• the configuration of the present invention will be described in detail.
• the polyester as a raw material for the polyester layer (A) and the polyester layer (B) is not particularly limited, but is preferably a polycondensation polymer of a dicarboxylic acid and a diol, and the dicarboxylic acid is an aromatic dicarboxylic acid.
• the aliphatic diol is preferable as the diol.
• aromatic dicarboxylic acid examples include terephthalic acid, isophthalic acid, orthophthalic acid, biphenyldicarboxylic acid, diphenylether-dicarboxylic acid, diphenylsulfone-dicarboxylic acid, diphenylketone-dicarboxylic acid, 2,6-naphthalenedicarboxylic acid, and 1,4-naphthalene. Examples thereof include dicarboxylic acid and 2,7-naphthalenedicarboxylic acid.
• terephthalic acid isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, and 4,4'-biphenyldicarboxylic acid are preferable, and terephthalic acid is more preferable.
• Aliphatic diols include those having a linear or branched structure such as ethylene glycol, 2-butene-1,4-diol, trimethylene glycol, tetramethylene glycol, hexamethylene glycol, neopentyl glycol, methylpentanediol and diethylene glycol.
• ethylene glycol, neopentyl glycol and cyclohexanedimethanol are preferable, and ethylene glycol is more preferable.
• the polyester used in the present invention is a polyester resin in which 50 mol% or more of the dicarboxylic acid unit is a constituent unit derived from terephthalic acid and 50 mol% or more of the diol unit is a constituent unit derived from ethylene glycol, that is, It is preferable to use polyethylene terephthalate. If it is polyethylene terephthalate, the polyester resin is less likely to become amorphous, and the transparency and light resistance are improved.
• the dicarboxylic acid unit is preferably 70 mol% or more, more preferably 90 mol% or more is a constituent unit derived from terephthalic acid, and the diol unit is preferably 70 mol% or more, further preferably 90 mol% or more. More than mol% is a structural unit derived from ethylene glycol.
• the polyester resin may be composed of polyethylene terephthalate alone, but may contain a polyester resin other than polyethylene terephthalate in addition to polyethylene terephthalate.
• the amount of polyethylene terephthalate in the total amount of the polyester resin is preferably 80 to 100% by mass, more preferably 90 to 100% by mass.
• the polyethylene terephthalate used in the present invention is preferably composed of only structural units derived from terephthalic acid and ethylene glycol, but may contain structural units derived from bifunctional compounds other than terephthalic acid and ethylene glycol.
• bifunctional compounds include the aromatic dicarboxylic acids and aliphatic diols other than terephthalic acid and ethylene glycol, and bifunctional compounds other than aromatic dicarboxylic acids and aliphatic diols.
• bifunctional compound other than the aromatic dicarboxylic acid and the aliphatic diol examples include linear or branched aliphatic bifunctional compounds, and specifically, malonic acid, succinic acid, adipic acid, azelaic acid and Aliphatic dicarboxylic acids such as sebacic acid; aliphatic hydroxycarboxylic acids such as 10-hydroxyoctadecanoic acid, lactic acid, hydroxyacrylic acid, 2-hydroxy-2-methylpropionic acid and hydroxybutyl acid can be mentioned.
• alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid, norbornenedicarboxylic acid and tricyclodecanedicarboxylic acid
• alicyclic hydroxy such as hydroxymethylcyclohexanecarboxylic acid, hydroxymethylnorbornenecarboxylic acid and hydroxymethyltricyclodecanecarboxylic acid.
• An alicyclic bifunctional compound such as a carboxylic acid can also be mentioned.
• aromatic hydroxycarboxylic acids such as hydroxybenzoic acid, hydroxytoryl acid, hydroxynaphthic acid, 3- (hydroxyphenyl) propionic acid, hydroxyphenylacetic acid and 3-hydroxy-3-phenylpropionic acid; and bisphenol compounds and Aromatic diols such as hydroquinone compounds can also be mentioned.
• the structural unit derived from the bifunctional compound is preferably 20 mol% or less, more preferably 10 mol% or less, based on the total moles of all the structural units constituting the polyester resin.
• the aromatic dicarboxylic acid is isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, and 4,4'-biphenyldicarboxylic acid.
• One or more selected from the above is preferable. These are low in cost, and the copolymerized polyester resin containing one of them is easy to manufacture.
• the proportion of the constituent unit derived from the aromatic dicarboxylic acid is preferably 1 to 20 mol% of the dicarboxylic acid unit, preferably 1 to 10 mol%. Is more preferable.
• the polyethylene terephthalate used in the present invention contains a structural unit derived from an aliphatic diol other than ethylene glycol, the aliphatic diol is preferably diethylene glycol.
• the proportion of the composition derived from diethylene glycol is preferably 0.1 to 10 mol% of the diol unit, and more preferably 0.4 to 5 mol%.
• the ultimate viscosity of the polyester resin used in the present invention is not particularly limited, but is preferably 0.45 to 1.0 dl / g, more preferably 0.5 to 0.9 dl / g, from the viewpoint of film forming property, productivity and the like. preferable.
• the amount of polyester in the polyester layer (A) and the polyester layer (B) is preferably 70% by mass or more, more preferably 80% by mass or more, and further preferably 90% by mass or more. preferable. When the amount of polyester is at least the above lower limit value, the flexibility, strength and the like of the polyester film can be ensured.
• the polyester film of the present invention has a polyester layer (A) containing a black pigment. Since the polyester layer (A) contains a black pigment, the polyester film has a light-shielding property.
• a black pigment having a high hiding power is preferable from the viewpoint of light-shielding property and surface smoothness of the polyester film.
• the light-shielding property of the polyester film that is, the transmission concentration (OD value) can be improved even with a small amount, and the roughness of the polyester film surface can be suppressed with a small amount.
• black pigments include carbon black (furness black, channel black, acetylene black, thermal black, lamp black, etc.), carbon nanotubes, graphite, copper oxide, manganese dioxide, titanium black, activated carbon, ferrite, magnetite, chromium oxide, and oxidation.
• Inorganic black pigments such as iron and molybdenum disulfide, and organic black pigments such as aniline black, perylene black, cyanine black, chromium complex, composite oxide black pigment, and anthraquinone organic black pigment can be mentioned from the viewpoint of concealment.
• Inorganic black pigments are preferred. One of these black pigments may be used alone, or two or more thereof may be used in combination.
• black pigments inorganic black pigments are more preferable from the viewpoint of light-shielding effect, and carbon black is particularly preferable.
• the average primary particle size is preferably 5 to 100 nm, more preferably 10 to 50 nm, and even more preferably 15 to 40 nm.
• the average primary particle size is not more than the upper limit value, the dispersibility in the polyester layer (A) is improved, and the surface smoothness of the polyester film is improved.
• fine primary particles may aggregate and exist as an agglomerate, but when this agglomerate is present in polyester and biaxially stretched, the stretching stress applied to the film becomes this agglomerate. The phenomenon of dispersion can be seen.
• the average primary particle size in the present invention is a particle size measured by observing carbon black particles existing alone or in polyester with an electron microscope, and when the particles are present as agglomerates. , Refers to the particle size of the primary particles that make up this.
• the content of the black pigment in the polyester layer (A) is preferably 0.1 to 25.0% by mass, more preferably 0.5 to 20.0% by mass, and 1.0 to 10%. It is further preferably 0.0% by mass, and even more preferably 1.5 to 5.0% by mass.
• the content of the black pigment is at least the above lower limit value, sufficient light-shielding property can be imparted to the polyester film, and the OD value can be easily increased.
• the content of the black pigment is not more than the upper limit value, the black pigment is easily dispersed in the polyester layer, so that the surface smoothness is improved.
• the content of the black pigment is increased, the black pigment is likely to aggregate, but even if the black pigment is aggregated, the surface smoothness can be ensured by providing the polyester layer (B).
• the black pigment is carbon black
• the content of carbon black is preferably 0.1 to 5.0% by mass, more preferably 0.5 to 4.0% by mass, and 1 It is more preferably 2 to 3.0% by mass.
• the content of carbon black is within the above range, sufficient light-shielding property can be obtained while keeping the amount of pigment used low.
• carbon black may agglomerate, but if the content is within the above range, by providing the polyester layer (B), the surface smoothness due to the agglutination is not impaired, and excellent surface smoothness can be ensured.
• the polyester layer (A) may contain a conventionally known antioxidant, ultraviolet absorber, heat stabilizer, lubricant, or the like, if necessary.
• the polyester layer (B) is a polyester layer provided on at least one surface of the polyester layer (A) and contains substantially no particles or contains particles (X) having an average particle size of 1.0 ⁇ m or less. It is a layer to do.
• the polyester layer (B) having particles having substantially no particles or having a small average particle size on the surface of the polyester layer (A) having a pigment excellent surface smoothness can be obtained. It is obtained, which provides excellent visibility.
• the polyester layer (B) may be provided on at least one surface of the polyester layer (A), but the polyester layer (B) may be provided on both sides of the polyester layer (A). ..
• the polyester layers (B) By having the polyester layers (B) on both sides of the polyester layer (A), the surface smoothness of both sides can be improved. Further, by providing the polyester layers (B) on both sides, it becomes easy to reduce the difference in glossiness, and it is not necessary to check in advance each time the film surface on which the metal layer is provided is processed, which has an advantage of improving work efficiency. Has.
• the average particle size of the particles (X) in the polyester layer (B) is 1.0 ⁇ m or less as described above. When the average particle size is larger than 1.0 ⁇ m, the surface smoothness of the polyester film becomes low.
• the average particle size of the particles (X) in the polyester layer (B) is preferably 0.01 to 0.8 ⁇ m, more preferably 0.02 to 0.4 ⁇ m, and 0.02 to 0. It is preferably 15 ⁇ m.
• the average particle size of the particles is set to be equal to or less than the upper limit value, the smoothness of the surface can be improved. Further, when it is at least the lower limit value, it becomes easy to impart slipperiness or the like to the surface of the polyester film.
• the average particle size of the particles (X) is integrated in the equivalent spherical distribution in which the powder is measured using a centrifugal sedimentation type particle size distribution measuring device (SA-CP3 type) when these are powders.
• SA-CP3 type centrifugal sedimentation type particle size distribution measuring device
• the particle size (d50) having a body integration rate of 50% can be used as the average particle size.
• the average particle size of the particles (X) in the polyester film is determined from the image data obtained by observing the film using, for example, a scanning electron microscope (manufactured by Hitachi High-Technologies Corporation, "S3400N"). The size of one particle is measured, and the average value of 10 points (10 particles) is taken as the average particle size.
• Examples of the particles (X) contained in the polyester layer (B) include inorganic particles such as silica, aluminum oxide, calcium carbonate, and kaolin, and organic polymer particles.
• Inorganic particles are preferable from the viewpoint of effectively improving surface smoothness and manufacturing cost, and aluminum oxide such as spherical alumina, calcium carbonate, and silica are more preferable. Further, aluminum oxide is more preferable from the viewpoint of reducing the average particle size to lower the surface smoothness and improving the slipperiness.
• the content of the particles (X) is preferably 0.01 to 1.0% by mass.
• the content of the particles (X) is preferably 0.05 to 0.5% by mass, more preferably 0.1 to 0.4% by mass.
• the polyester layer (B) contains substantially no particles.
• substantially free of particles means that the content of particles in the polyester layer (B) is less than 100 mass ppm.
• the polyester layer (B) may contain fine particles such as a polymerization catalyst (for example, antimony trioxide) and impurities inevitably mixed in the manufacturing process as described above. Although it is possible, the effect on smoothness is minor even if a small amount of particles are contained, and the surface smoothness is maintained well.
• the particles in the polyester layer (B), which are contained in a trace amount in a manner substantially free of particles preferably have an average particle size of 1 ⁇ m or less, but the average particle size may exceed 1 ⁇ m.
• the content of the particles in the polyester layer (B) is preferably 50 mass ppm or less, more preferably 30 mass ppm or less, and 1 mass ppm. The following is more preferable.
• the polyester layer (B) may be blended with conventionally known antioxidants, ultraviolet absorbers, heat stabilizers, lubricants and the like, if necessary.
• the permeation concentration (OD value) of the polyester film of the present invention is 0.4 or more. If the transmission concentration is less than the lower limit, the polyester film does not have sufficient light-shielding properties, so that when it is used in an electronic device, the internal circuit, substrate, and the like can be visually recognized. From the viewpoint of ensuring sufficient light-shielding property and making the inside of the small electronic device invisible, the transmission concentration (OD value) is preferably 1.0 or more, more preferably 3.5 or more. It is more preferably 0 or more. In order to make the permeation concentration (OD value) of the polyester film of the present invention equal to or higher than the above value, the pigment of the polyester layer (A) is added for adjustment.
• the permeation concentration (OD value) can be set to be equal to or higher than the above value, and since a small amount is added, the influence on the surface roughness of the polyester film can be reduced.
• the arithmetic mean height (Sa) on the surface of the polyester film on the polyester layer (B) side is preferably 20.0 nm or less.
• the arithmetic mean height (Sa) is not more than the above upper limit value, the smoothness is excellent, and unevenness is unlikely to occur even on the surface of the polyester film after sputtering, for example, so that a polyester film having excellent metallic luster is obtained. be able to.
• the arithmetic mean height (Sa) is more preferably 15.0 nm or less, and further preferably 7.0 nm or less.
• the arithmetic mean height (Sa) is preferably low from the viewpoint of smoothness, but is, for example, 1.0 nm or more, preferably 2.0 nm or more from the viewpoint of imparting a certain slipperiness.
• the arithmetic mean height (Sa) can be measured by the method described in Examples.
• the type and content of the pigment in the polyester layer (A) and the polyester layer (B) It can be adjusted by the type and content of the particles (X) inside, the thickness of the polyester layer (B), the thickness ratio of the polyester layer (A) and the polyester layer (B), and the like. The same applies to the maximum height (Sp) described later.
• the surface of the polyester film on the polyester layer (B) side is the polyester layer provided on only one side of the polyester layer (A) when the polyester layer (B) is provided on only one side of the polyester layer (A). This is the surface on the (B) side.
• the polyester layer (B) is provided on both sides of the polyester layer (A)
• it means the surface on the polyester layer (B) side
• the arithmetic of the surface on the polyester layer (B) side The average height (Sa) may be within the above range, but the arithmetic mean height (Sa) of both surfaces of the polyester film may be within the above range.
• the surface of the polyester film on the polyester layer (B) side is, as will be described later, when a layer such as an easy-adhesive layer or an easy-slip layer is further provided on the surface of the polyester layer (B) of the polyester film. It means the surface of the layer (easy-adhesive layer, easy-slip layer, etc.), and the arithmetic mean height (Sa) of the surface of the layer may be within the above range. The same applies to the maximum height (Sp) described later.
• the maximum height (Sp) on the surface of the polyester film on the polyester layer (B) side is preferably 1,000 nm or less, more preferably 500 nm or less, and further preferably 200 nm or less. It is preferably 150 nm or less, and even more preferably 150 nm or less.
• the maximum height (Sp) value is large, the surface of the film is given a grainy feeling, but when it is not more than the upper limit value, the graininess is reduced and an excellent metallic luster can be imparted to the polyester film.
• the maximum height (Sp) is preferably low from the viewpoint of reducing the graininess, but is, for example, 10.0 nm or more, preferably 20.0 nm or more from the viewpoint of imparting a certain slipperiness.
• the maximum height (Sp) can be measured by the method described in Examples.
• the difference in glossiness between the front and back surfaces of the polyester film of the present invention is 3.0 or less, preferably 2.0 or less, and more preferably 1.5 or less.
• the difference in glossiness between the front and back surfaces of the polyester film of the present invention is 3.0 or less, preferably 2.0 or less, and more preferably 1.5 or less.
• the thickness of the polyester layer (A) is preferably 20 to 70 ⁇ m, more preferably 25 to 60 ⁇ m, and more preferably 30 to 50 ⁇ m. More preferred.
• the thickness of the polyester layer (B) is preferably 0.5 to 20 ⁇ m. When the thickness is 20 ⁇ m or less, the thickness of the polyester film can be reduced, and when the thickness is 0.5 ⁇ m or more, good surface smoothness can be easily maintained. From these viewpoints, the thickness of the polyester layer (B) is more preferably 1.5 to 15 ⁇ m, and further preferably 4.0 to 10 ⁇ m.
• the thickness of the polyester layer (B) is 4.0 ⁇ m or more, it becomes easier to further reduce the unevenness caused by the particles (X) having an average particle size of 1 ⁇ m or less, and the above-mentioned while containing the particles (X). It becomes easy to reduce the Sa and Sp.
• the ratio of the thickness of the polyester layer (B) to the thickness of the polyester layer (A) [thickness of (B) / thickness of (A)] is preferably 0.025 to 0.25. ..
• the thickness ratio [(B) / (A)] is more preferably 0.04 to 0.20, and even more preferably 0.09 to 0.18. It is generally considered that a highly smooth surface can be obtained without adding particles to the polyester layer of the surface layer, but this is not always the case when a black pigment is contained.
• the polyester film of the present invention may have a cured resin layer on the outermost surface.
• the cured resin layer By providing the cured resin layer, it is possible to easily reduce the heat damage to the base film or improve the adhesion to the metal layer in the process of forming the metal layer formed by sputtering or the like.
• the cured resin layer is an easy-adhesive layer, it may be provided on the surface of the polyester layer (B).
• the easy-adhesion layer may be provided on the surfaces of both polyester layers (B), but on the surface of one polyester layer (B). It may be provided.
• the easy-adhesion layer is formed from, for example, an easy-adhesion layer composition containing a binder resin and a cross-linking agent.
• the binder resin include polyester resin, acrylic resin, urethane resin, polyvinyl-based resin such as polyvinyl alcohol, polyalkylene glycol, polyalkyleneimine, methyl cellulose, hydroxycellulose, and starches.
• the content of the binder resin is, for example, 20 to 90% by mass, preferably 30 to 80% by mass, based on the solid content.
• cross-linking agent various known cross-linking agents can be used, and examples thereof include oxazoline compounds, melamine compounds, epoxy compounds, isocyanate compounds, carbodiimide compounds, and silane coupling compounds.
• an oxazoline compound is preferably used from the viewpoint of improving durability adhesion.
• a melamine compound is preferably used from the viewpoint of improving the durability and coatability of the easy-adhesion layer.
• the content of the cross-linking agent in the easy-adhesion layer composition is, for example, 5 to 50% by mass, preferably 10 to 40% by mass based on the solid content.
• the easy-adhesion layer composition may contain particles within a range that does not impair the adhesiveness of the easy-adhesion layer and the smoothness of the surface of the polyester film.
• the particles those shown in the easy-to-slip layer described later can be appropriately used.
• the content of particles in the easy-adhesion layer composition is, for example, 1 to 20% by mass, preferably 3 to 15% by mass, based on the solid content.
• the easy-adhesion layer composition may contain a component for promoting cross-linking, for example, a cross-linking catalyst or the like.
• a defoaming agent a coating property improving agent, a thickener, an organic lubricant, an antistatic agent, an ultraviolet absorber, an antioxidant, a foaming agent, a dye, a pigment and the like in combination.
• the easy-adhesion layer composition is generally preferably diluted with water, an organic solvent, or a mixture thereof, and the easy-adhesion layer is a diluted solution of the easy-adhesion layer composition on the outermost surface of the polyester film. It is preferable to coat it as a coating liquid and dry it to form it. The coating may be carried out by a conventionally known method.
• the thickness of the easy-adhesion layer is usually in the range of 0.003 to 1 ⁇ m, preferably 0.005 to 0.6 ⁇ m, and more preferably 0.01 to 0.4 ⁇ m. Sufficient adhesiveness can be ensured by setting the thickness to 0.003 ⁇ m or more. Further, by setting it to 1 ⁇ m or less, deterioration of appearance and blocking are less likely to occur.
• the polyester film of the present invention may have an easy-slip layer on the outermost surface.
• the slippery layer is preferably provided on the surface of the polyester layer (B).
• the slippery layer may be provided on the surfaces of both polyester layers (B), but on the surface of one polyester layer (B). It may be provided. Further, it is preferable that the polyester film of the present invention is provided with the above-mentioned easy-adhesion layer on one surface and the above-mentioned easy-slip layer on the other surface.
• the easy-adhesion layer is provided on the surface of one polyester layer (B) and easily slips on the surface of the other polyester layer (B). It is preferable that a layer is provided.
• the easy-adhesive layer and the easy-slip layer are provided on each surface in this way, the easy-slip layer improves the transport between rolls and improves workability, while the easy-adhesive layer has a metal layer or the like on the surface. It becomes easy to stack other layers.
• the slippery layer is formed from, for example, a slippery layer composition containing a binder resin, a cross-linking agent and particles.
• the compounds that can be used as the binder resin and the cross-linking agent are as described in the binder resin and the cross-linking agent used for the easy-adhesion layer.
• the content of the binder resin in the easy-to-slip layer composition is, for example, 20 to 90% by mass, preferably 30 to 80% by mass, based on the solid content.
• the content of the cross-linking agent in the easy-to-slip layer composition is, for example, 5 to 50% by mass, preferably 10 to 40% by mass based on the solid content.
• the particles used in the slippery layer include silica, alumina, kaolin, calcium carbonate, and organic polymer particles.
• silica is preferable from the viewpoint of transparency.
• the average particle size of the particles is preferably 0.005 to 1.0 ⁇ m, more preferably 0.01 to 0.8 ⁇ m, still more preferably, from the viewpoint of improving the slipperiness without impairing the surface smoothness of the polyester film. Is in the range of 0.01 to 0.6 ⁇ m.
• the average particle size can be measured by the same method as for the particles (X).
• the content of particles in the easy-to-slip layer composition is, for example, 1 to 20% by mass, preferably 3 to 15% by mass, based on the solid content.
• one kind of particles may be used for the slippery layer, it is also preferable to use two kinds of particles having different average particle diameters in combination.
• the I Ching layer composition is generally preferably diluted with water, an organic solvent, or a mixture thereof, and for the I Ching layer, the diluted solution of the I Ching layer composition is applied to the outermost surface of the polyester film. It is preferable to coat it as a coating liquid and dry it to form it. The coating may be carried out by a conventionally known method.
• the thickness of the slippery layer is usually in the range of 0.003 to 1 ⁇ m, preferably 0.005 to 0.6 ⁇ m, and more preferably 0.01 to 0.4 ⁇ m. By setting the thickness to 0.003 ⁇ m or more, the particles contained in the slippery layer can be sufficiently retained and slipperiness can be imparted. Further, by setting it to 1 ⁇ m or less, deterioration of appearance and blocking are less likely to occur.
• the polyester film of the present invention is preferably used in applications that require light-shielding properties and surface smoothness, and is preferably used in, for example, electronic device applications, especially communication terminals.
• electronic device applications such as around a housing or a display
• surface smoothness for example, even if a metal layer described later is laminated, the smoothness of the metal layer can be ensured and the design property is improved.
• the polyester film of the present invention preferably has a metal layer laminated on its surface and is used as a polyester film with a metal layer.
• the metal layer may be laminated on the surface of the polyester film on the polyester layer (B) side.
• the polyester film with a metal layer has a metallic luster and can improve the design. Since the surface on the polyester layer (B) side is smooth as described above, the metal layer provided on the surface is also smooth, and the graininess is less likely to be seen.
• the metal layer may be provided on the surfaces of both polyester layers (B), but one polyester layer (B) It may be provided on the surface of.
• the easy-adhesive layer is provided on the surface of the polyester layer (B) as described above, it is preferable to laminate a metal layer on the easy-adhesive layer.
• the metal layer may be directly laminated on the surface of the polyester layer (B) without passing through the easy-adhesion layer.
• the thickness of the metal layer is not particularly limited, but is preferably 5 to 900 nm, more preferably 10 to 300 nm.
• the thickness of the metal layer is at least the above lower limit value, the metal layer is less likely to crack and becomes a strong metal layer.
• the thickness of the metal layer is not more than the upper limit value, the metal layer can be formed in a short time. Further, when the content is within the above range, sufficient metallic luster can be imparted.
• a conventionally known method can be adopted. Specifically, it can be formed by one or more methods selected from a vapor deposition method, a sputtering method and an ion plating method, but from the viewpoint of ease of production, it is particularly preferable to form by a sputtering method.
• a sputtering method a polyester film is placed in a vacuum vessel, an inert gas such as argon is introduced, a DC voltage is applied, the ionized inert gas is made to collide with a target metal, and the beaten metal is used. It is preferable to form a metal layer on the surface of the polyester film.
• the base film of the polyester film with a metal layer in the present invention is black, the metal layer can be inspected at the same time in the process of forming the metal layer by sputtering and in the process of winding the film.
• the metal layer can be inspected at the same time in the process of forming the metal layer by sputtering and in the process of winding the film.
• a polyester film with a metal layer using a black base film as in the present invention backside reflection derived from the base film as described above does not occur, and a highly accurate metal layer can be inspected. Furthermore, by making the surface of the base film on the side where the metal layer is provided highly smooth, the light emitted to the surface of the metal layer at the time of inspection faces the same direction, is reflected and returned to the detector, so that the inspection accuracy is further improved. Has the advantage of improving.
• the polyester film with a metal layer of the present invention is suitably used as a film laminate in which an optical member is laminated on the surface of a metal layer via an adhesive layer.
• the optical member include resin films such as a polarizer film, a protective film, a retardation film, and a protective film, and a glass substrate of a liquid crystal cell and the like are preferably used.
• the glass substrate is replaced with a resin film, when a resin film such as a polyimide film, a polyester film, or a cyclic polyolefin is bonded to a polyester film with a metal layer via an adhesive layer, the future is technically considered. It is expected that further thinning will progress.
• the total thickness of the film laminate is preferably 150 ⁇ m or less, more preferably 130 ⁇ m or less, and particularly preferably 100 ⁇ m or less. Further, in the film laminate, it is possible to impart bending characteristics by appropriately selecting the resin films to be combined. It is also possible to support various display applications such as foldable, bendable, and rollable, and it is expected that the applicable range of the film laminate will be further expanded.
• the method for producing the polyester film of the present invention will be specifically described, but the method is not limited to the following production method.
• an additive such as the pigment or particles is added to the polyester to produce a raw material for the polyester layer (A) or the polyester layer (B).
• a twin-screw extruder it is particularly preferable to use a twin-screw extruder in order to disperse and knead the raw material well.
• the raw materials of the polyester layer (A) and the polyester layer (B) are put into a plurality of extruders, respectively, and each polyester is laminated using a multi-layer multi-manifold die or a feed block to form a plurality of layers from the base.
• the molten sheet is extruded and cooled and solidified with a cooling roll to obtain an unstretched sheet.
• the obtained unstretched film is stretched in the biaxial direction and biaxially oriented. That is, the unstretched sheet is stretched in the vertical direction by a roll stretching machine.
• the stretching temperature is usually 70 to 120 ° C., preferably 75 to 110 ° C., and the stretching ratio is usually 2.5 to 7.0 times, preferably 3.0 to 6.0 times.
• stretching is performed in the lateral direction.
• the stretching temperature is usually 70 to 125 ° C., preferably 80 to 120 ° C., and the stretching ratio is usually 3.0 to 7.0 times, preferably 3.5 to 6.0 times.
• the heat treatment is subsequently performed at a temperature of 170 to 250 ° C. under tension or relaxation within 30% to obtain a biaxially stretched film.
• a method of stretching in one direction in two or more steps can also be used. In that case, it is preferable to finally set the stretching ratios in the two directions within the above ranges. It is also possible to simultaneously biaxially stretch the unstretched sheet so that the area magnification is 10 to 40 times. Further, if necessary, it may be stretched again in the vertical and / or horizontal directions before or after the heat treatment.
• the surface of the polyester film obtained by the above method can be coated as needed, and the above-mentioned easy-adhesive layer and easy-slip layer may be formed by the coating.
• the coating can be in-line, offline, or a combination of both, but is preferably in-line.
• in-line coating a series of processes can be used in which a coating liquid diluted mainly with water is applied at the stage when the longitudinal stretching is completed, and then drying, preheating, and transverse stretching are performed in the tenter, and further heat fixing is performed. ..
• a "sheet” is a thin product according to the definition in JIS, and its thickness is small and flat for its length and width.
• a "film” is thicker than its length and width.
• a thin, flat product that is extremely small and has an arbitrarily limited maximum thickness, and is usually supplied in the form of a roll (Japanese Industrial Standards; JIS K6900).
• JIS K6900 Japanese Industrial Standards
• the boundary between the sheet and the film is not clear, and it is not necessary to distinguish between the two in the present invention. Therefore, in the present invention, even when the term “film” is used, the term “sheet” is included and the term “sheet” is used. Even if it is, it shall include "film”.
• X to Y (X and Y are arbitrary numbers) is described, it means “X or more and Y or less” and “preferably larger than X” or “preferably larger than X” unless otherwise specified. Is smaller than Y ”.
• X or more (X is an arbitrary number) is described, it includes the meaning of "preferably larger than X” and is described as “Y or less” (Y is an arbitrary number) unless otherwise specified. Unless otherwise specified, it also includes the meaning of "preferably smaller than Y”.
• OD value Permeation concentration
• Arithmetic mean height (Sa) and maximum height (Sp) The surface of the polyester film on the polyester layer (B) side is a non-contact surface / layer cross-sectional shape measurement system VertScan (registered trademark) R550GML manufactured by Ryoka System Co., Ltd., and a CCD camera: SONY HR-50 1/3.
• VertScan registered trademark
• R550GML manufactured by Ryoka System Co., Ltd.
• CCD camera SONY HR-50 1/3.
• Objective lens 20x
• Lens barrel 1X Body
• Zoom lens No Relay
• Wavelength filter 530 white
• Measurement mode Wave
• measure the area of 640 ⁇ m x 480 ⁇ m measure the area of 640 ⁇ m x 480 ⁇ m, and output by 4th order polynomial correction.
• the arithmetic average height (Sa) and maximum height (Sp) were calculated using this. Ten points were measured, and the average values were taken as the arithmetic mean height (Sa) and the
• polyester A Polyethylene terephthalate homopolymer with an ultimate viscosity of 0.65 dl / g.
• Polyethylene terephthalate homopolymer with an ultimate viscosity of 0.65 dl / g.
• ⁇ Polyester B 80 parts by mass of polyester A and 20 parts by mass of carbon black particles having an average primary particle size of 20 nm were dry-blended and extruded using a twin-screw kneading extruder to obtain polyester B.
• the ultimate viscosity of the obtained polyester B was 0.58 dl / g.
• polyester E Polyester A is pre-crystallized at 160 ° C. and then solid-phase polymerized in a nitrogen atmosphere at 220 ° C., and the intrinsic viscosity is 0.70 dL / g, 99% by mass of ester units is ethylene terephthalate, and the remaining ester units.
• polyethylene terephthalate which is a polymer of diethylene glycol and terephthalic acid.
• polyesters A and B were mixed at a ratio of 90% by mass and 10% by mass, respectively, and used as a raw material for the polyester layer (A). Further, the polyesters D and F are mixed at a ratio of 92.5% by mass and 7.5% by mass, respectively, and used as a raw material for the polyester layer (B) which is a surface layer by a melt extruder to form a B layer / A layer / B.
• a two-kind, three-layer laminated polyester resin having a layer structure was co-extruded into a film, and the sheet was co-extruded onto a casting drum cooled to 20 ° C. and cooled and solidified to obtain an unoriented sheet.
• Example 2 A polyester film having a thickness of 50 ⁇ m was obtained in the same manner as in Example 1 except that the layer structure and thickness were changed as shown in Table 1.
• Example 3 The polyesters E and G were mixed at a ratio of 98.5% by mass and 1.5% by mass, respectively, to be used as a raw material for the polyester layer (B), except that the layer composition and thickness were changed as shown in Table 1. A polyester film having a thickness of 50 ⁇ m was obtained in the same manner as in Example 1.
• Example 4 Except that the polyesters A and B were mixed at a ratio of 89% by mass and 11% by mass to be used as a raw material for the polyester layer (A), and the layer structure and thickness were changed as shown in Table 1, the same as in Example 3. Similarly, a polyester film having a thickness of 50.2 ⁇ m was obtained.
• Example 5 A polyester film having a thickness of 50 ⁇ m was obtained in the same manner as in Example 1 except that the polyester E was used as a raw material for the polyester layer (B) and the layer structure and thickness were changed as shown in Table 1.
• the polyester layer (B) contained less than 100 mass ppm of particles and was substantially free of particles.
• Example 6> A polyester film having a thickness of 50 ⁇ m was obtained in the same manner as in Example 5, except that the layer structure and thickness were changed as shown in Table 1.
• the polyester layer (B) contained less than 100 mass ppm of particles and was substantially free of particles.
• ⁇ Comparative example 1> A mixture of polyesters A and B at a ratio of 95% by mass and 5% by mass, respectively, was melt-extruded by a melt extruder, and a sheet was co-extruded onto a casting drum cooled to 20 ° C. to cool and solidify the single layer. Non-oriented sheet was obtained. Next, after stretching 3.2 times at 80 ° C. in the machine direction (longitudinal direction), the film edge is then gripped with a clip and guided into the tenter, and through a preheating process, 115 in the direction perpendicular to the machine direction (horizontal direction). It was stretched 4.0 times at ° C. After biaxial stretching, heat treatment was performed at 234 ° C. for 3 seconds to obtain a polyester film having a thickness of 50 ⁇ m.
• the surface of the polyester layer (A) having a black pigment contains substantially no particles or contains particles (X) having an average particle size of 1.0 ⁇ m or less.
• the polyester layer (B) both the light-shielding property and the surface smoothness were improved. Further, since the difference in glossiness can be reduced, the visibility is improved regardless of which surface the metal layer is provided. Further, as is clear from the results in Table 1, Examples 3 and 4 using alumina having a relatively thick polyester layer (B) and a small particle size, and the polyester layer (B) do not contain particles. It can be seen that Examples 5 and 6 are particularly excellent in light-shielding property and surface smoothness.
• Examples 3, 4 and 6 having a thick polyester layer (B) are preferable from the viewpoint of surface smoothness, and from the viewpoint of workability, the slipperiness is improved by using alumina particles.
• Examples 3 and 4 described above are suitable. It can be seen that in Comparative Example 3, since the glossiness of the front and back surfaces is different, the reflected image is distorted, and there is a moody feeling due to the graininess of the film, and the visibility on the rough surface side is lowered. Therefore, it is not suitable for the surface on which the metal layer is provided, and there is an inconvenience that the film surface must be inverted when the film is used.

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