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
  • B32B17/00—Layered products essentially comprising sheet glass, or glass, slag, or like fibres
• • 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
• • 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
  • B32B7/02—Physical, chemical or physicochemical properties
  • B32B7/023—Optical properties
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B5/00—Optical elements other than lenses
  • G02B5/08—Mirrors
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B5/00—Optical elements other than lenses
  • G02B5/20—Filters
  • G02B5/26—Reflecting filters

Definitions

• the present invention relates to a laminated film.
• Laminated films are known that selectively reflect light of specific wavelengths by utilizing the optical interference phenomenon that occurs when two or more materials with different optical properties are alternately laminated in layers with thicknesses at the level of the wavelength of light.
• Such laminated films can be endowed with a variety of performance properties by adjusting the refractive index, number of layers, and thickness of each layer of the materials used, and are therefore used in applications such as cold mirrors, half mirrors, laser mirrors, dichroic filters, heat ray reflective films, near-infrared cut filters, monochrome filters, and polarized reflective films.
• the molded articles obtained by laminating such laminated films onto a hard support under heat and pressure are used in decorative materials such as decorative panels, various home appliances, building materials, automotive parts, etc.
• heat-blocking glass which can reduce the inflow of heat from outside in the summer, especially heat from sunlight, has been attracting attention as window glass for vehicles such as cars and trains, and buildings.
• heat-ray-cutting glass examples include glass that contains a heat-ray absorbing material in the glass or in the interlayer film used in laminated glass, and blocks heat rays with the heat-ray absorbing material (for example, Patent Document 1), glass that is laminated with a film formed by sputtering or the like that reflects and blocks heat rays (for example, Patent Document 2), and glass that has a laminated film in which polymers with different refractive indices are alternately stacked, inserted between the glass and the interlayer film, which reflects and blocks heat rays (for example, Patent Document 3).
• Patent Document 1 glass that contains a heat-ray absorbing material in the glass or in the interlayer film used in laminated glass, and blocks heat rays with the heat-ray absorbing material
• Patent Document 2 glass that is laminated with a film formed by sputtering or the like that reflects and blocks heat rays
• Patent Document 3 glass that has a laminated film in which polymers with different refractive indices are alternately
• the difference in refractive index with the copolymer polyester, which has a low refractive index, can be made large, and therefore a laminated film with high reflectance can be obtained.
• Such heat-cutting glass is often used in places where it is visible to people, such as the window glass of vehicles and buildings, so the appearance is also an important factor.
• uneven pressing caused by uneven thickness of the interlayer used for lamination with the support and differences in thermal shrinkage stress with the interlayer film, etc. cause the laminated film to have uneven distortion during molding, which impairs the appearance.
• such laminated films utilize the interference reflection phenomenon by controlling the layer thickness, if the layer thickness changes due to uneven distortion, color unevenness and optical defects within the film surface become more noticeable.
• such laminated films also have the problem of being prone to wrinkles when laminated with a support or an interlayer film and molded. This problem occurs mainly at the ends of the molded body due to the laminated film's inability to follow the shape of the support during molding and the difference in thermal shrinkage rate with the interlayer film, etc.
• Patent Document 6 when a laminate film consisting of a layer mainly composed of polyethylene terephthalate and a layer of a copolymer polyester with a relatively low refractive index is produced by melt extrusion, the rigidity of the layers is lower than that of polyethylene naphthalate, so it is easier to deform, making it easier to apply to applications where the laminate film is deformed and processed.
• polyethylene terephthalate has a lower refractive index than polyethylene naphthalate, the reflectance of the laminate film is lower, resulting in inferior performance as a final product.
• the present invention aims to solve the above problems and provide a laminate film that reduces the occurrence of uneven distortion and color unevenness caused by molding involving heating and pressure in a molded product in which an intermediate film and a support are arranged on at least one side of the laminate film, and that can improve the appearance and design when formed into a molded product.
• DSC measurement differential scanning calorimetry
• the laminate film according to any one of [1] to [11] which is a film for laminated glass.
• a laminate comprising a support 1, an intermediate layer 1, the laminate film of [1] or [2], an intermediate layer 2, and a support 2 in this order.
• the present invention can provide a laminated film that reduces the occurrence of uneven distortion and color unevenness caused by molding involving heating and pressure, and can improve the appearance and design of the molded product.
• the laminated film of the present invention is a laminated film having a structure in which 51 or more layers of two or more different thermoplastic resin layers are regularly laminated, and is characterized in that, when the highest glass transition temperature determined by differential scanning calorimetry (DSC measurement) is TA and the shrinkage start temperature determined from the TMA curve in the main orientation direction is TX, the TX is 5°C to 30°C lower than the TA.
• DSC measurement differential scanning calorimetry
• the laminated film of the present invention has a structure in which 51 or more layers of two or more different thermoplastic resin layers are regularly laminated, and preferably has a structure in which 51 or more layers of two or more thermoplastic resin layers having different main components are regularly laminated.
• the "main component” refers to a component that is contained in an amount of more than 50% by mass and not more than 100% by mass when the total components constituting the thermoplastic resin layer are taken as 100% by mass, and the main component can be interpreted in the same manner hereinafter.
• “Thermoplastic resin layers are different” refers to a case where, when two thermoplastic resin layers are compared, at least one of the following 1 to 3 is satisfied, and preferably at least the following "2" is satisfied.
• thermoplastic resin layers when three or more types of thermoplastic resin layers are present, in order to say that all of them are different, it is necessary that, when comparing the two thermoplastic resin layers in any combination, at least one of the following 1 to 3 is satisfied (the same applies when four or more types of thermoplastic resin layers are present).
• 1 The refractive index differs by 0.01 or more in the main alignment direction (the method for specifying the main alignment direction will be described later).
• 2 Having different melting points or crystallization temperatures (different melting points or crystallization temperatures means that either the melting point or the crystallization temperature determined by the measurement method described below differs by 3°C or more.
• thermoplastic resin layer has a melting point and the other thermoplastic resin layer does not have a melting point, or when one thermoplastic resin layer has a crystallization temperature and the other thermoplastic resin layer does not have a crystallization temperature).
• the composition analyzed by nuclear magnetic resonance spectroscopy or gas chromatography mass spectrometry differs by 5 mass % or more.
• a structure in which 51 or more thermoplastic resin layers are regularly laminated refers to a structure in which 51 or more types of thermoplastic resin layers are laminated in the thickness direction with a certain regularity. Specific examples include, for example, when there are two different types of thermoplastic resin layers (layer A, layer B), the two types of layers are alternately laminated in the thickness direction, such as the structure A(BA)n and the structure B(AB)n (where the repeating unit is in parentheses and n is a natural number representing the number of repeating units, the same below), when the layers A and B are expressed as A and B.
• thermoplastic resin layers layer A, layer B, layer C
• layer A, layer B, layer C Specific examples when there are three different types of thermoplastic resin layers (layer A, layer B, layer C), include the structure (ABCB)nA and the structure (ABC)nA, when the layers A, B, and C are expressed as A, B, and C, respectively.
• ABSCB structure
• ABSC structure
• the laminated film can reflect light of a wavelength specified by the relationship between the difference in refractive index of each layer and the layer thickness.
• the number of regularly stacked layers is preferably 101 or more, and more preferably 401 or more.
• the more layers there are in a laminate film the better.
• the manufacturing equipment becomes larger, which increases the manufacturing costs, and from the viewpoint of preventing deterioration in handleability due to the thickness of the laminate film itself, the practical range is 1001 layers or less.
• the film has a reflection band of 100 nm or more in which the reflectance is 30% or more when light is incident on the film surface at an incident angle of 10° and a wavelength of 800 to 2000 nm. "Having a reflection band of 100 nm or more in which the reflectance is 30% or more” means that the film has at least one continuous band over a wavelength of 100 nm or more in which the reflectance is 30% or more.
• Sunlight has an intensity distribution mainly in the visible light range, and as the wavelength increases, the intensity distribution tends to become smaller.
• the laminate film of the present invention more preferably has a reflection band in which the reflectance is continuously 50% or more over 200 nm or more in the wavelength range of 900 to 1200 nm, and even more preferably has a reflectance of continuously 50% or more over the entire wavelength range of 900 to 1200 nm.
• the average reflectance in the wavelength range of 900 to 1200 nm is 70% or more, and it is even more preferable that the average reflectance in the wavelength range of 900 to 1200 nm is 80% or more.
• the average reflectance in the wavelength range of 900 to 1200 nm increases, it is possible to impart high heat ray blocking performance to the laminate film.
• Such a laminated film can be realized by increasing the difference in the in-plane refractive index between two or more resins with different optical properties, so in the case of a biaxially stretched film, a laminated film in which a layer mainly composed of a crystalline polyester resin and a layer mainly composed of a thermoplastic resin that can maintain its amorphousness even when stretched or that is melted in a heat treatment process are alternately laminated (in other words, it is preferable to use a laminated film in which a layer mainly composed of a crystalline thermoplastic resin and a layer mainly composed of a thermoplastic resin that can maintain its amorphousness even when stretched or that is melted in a heat treatment process are alternately laminated).
• the in-plane stretching ratio (the product of the stretching ratio in the vertical direction (also called the film transport direction, also called the longitudinal direction) and the stretching ratio in the horizontal direction (the width direction within the film plane in the transport direction)) described below to 9.0 times or more and 18.0 times or less, or to increase the number of layers.
• the in-plane stretching ratio the product of the stretching ratio in the vertical direction (also called the film transport direction, also called the longitudinal direction) and the stretching ratio in the horizontal direction (the width direction within the film plane in the transport direction) described below to 9.0 times or more and 18.0 times or less, or to increase the number of layers.
• the in-plane refractive index here is the average value of the refractive index in the main orientation direction and the refractive index in the direction perpendicular to the main orientation direction in the film plane (direction perpendicular to the main orientation). If the thermoplastic resin layer not located on the outermost surface is amorphous, the in-plane refractive index may be determined in any two directions perpendicular to the main orientation direction using a sheet obtained by vacuum drying the thermoplastic resin and then pressing it. This is because amorphous resins do not normally have birefringence, and the refractive index in each direction does not vary depending on whether or not the resin is stretched.
• the refractive index can be measured using a laser with a wavelength of 632.8 nm, and a measuring device such as the "SPA-4000" manufactured by SAIRON TECHNOLOGY, INC. can be used.
• Crystalline here means that the heat of fusion is 5 J/g or more in differential scanning calorimetry (DSC).
• amorphous means that the heat of fusion is less than 5 J/g.
• Crystalline polyester resins can be oriented and crystallized in the stretching and heat treatment process to give them a higher in-plane refractive index than when they were in an amorphous state before stretching.
• the slight orientation that occurs in the stretching process can be greatly alleviated by performing heat treatment at a temperature far above the glass transition temperature in the heat treatment process, and the low refractive index of the amorphous state can be maintained.
• a refractive index difference can be easily created between the crystalline polyester resin and the amorphous polyester resin in the stretching and heat treatment processes in the production of the laminate film.
• the outermost layers on both sides are layers with relatively high crystallinity (layers whose main component is a crystalline thermoplastic resin) in order to prevent adhesion to rolls, etc. during film production.
• layers with relatively high crystallinity layers whose main component is a crystalline thermoplastic resin
• a laminate film having such a structure will be described, and unless otherwise specified, the layer with relatively high crystallinity will be described as layer A and the layer with low crystallinity will be described as layer B.
• optical thicknesses of the adjacent A layer and B layer simultaneously satisfy the following formulas (1) and (2).
• the in-plane refractive index of the film surface after molding and stretching a thermoplastic resin is about 1.4 to about 1.9, so by setting the thickness ratio of adjacent A layer to B layer (thickness of A layer/thickness of B layer) to 0.7 or more and 1.4 or less, a laminated film that suppresses even-order reflection can be obtained. From the above viewpoint, therefore, it is preferable that the thickness ratio of adjacent A layer to B layer (thickness of A layer/thickness of B layer) is 0.7 or more and 1.4 or less, more preferably 0.8 or more and 1.2 or less.
• thermoplastic resin A and B must be different from each other.
• Thermoplastic resin A and thermoplastic resin B can be polyester resin, acrylic resin, polycarbonate resin, etc. Among them, it is preferable to use polyester resin as thermoplastic resin A and thermoplastic resin B because of its excellent transparency and moldability.
• thermoplastic resin C is also a polyester resin.
• polyester resin refers to a polymer obtained by condensation polymerization of a dicarboxylic acid component and a diol component.
• examples of dicarboxylic acid units of the polyester resins used for thermoplastic resin A, thermoplastic resin B, and thermoplastic resin C include structural units such as terephthalic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid (1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid), 4,4'-diphenyldicarboxylic acid, 4,4'-diphenylsulfonedicarboxylic acid, adipic acid, sebacic acid, dimer acid, cyclohexanedicarboxylic acid, and their ester-forming derivatives.
• structural units such as terephthalic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid (1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic
• the diol units of the polyester resins include structural units such as ethylene glycol, 1,2-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, diethylene glycol, polyalkylene glycol, 2,2-bis(4'- ⁇ -hydroxyethoxyphenyl)propane, isosorbate, 1,4-cyclohexanedimethanol, spiroglycol, neopentyl glycol, polyethylene glycol, polypropylene glycol, polybutylene glycol, triethylene glycol, tetraethylene glycol, polytetramethylene ether glycol, and ester-forming derivatives thereof.
• structural units such as ethylene glycol, 1,2-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, diethylene glycol, polyalkylene glycol, 2,2-bis(4'
• the dicarboxylic acid units constituting the polyester resin include terephthalic acid, 2,6-naphthalenedicarboxylic acid, isophthalic acid, etc.
• the diol units include ethylene glycol, 1,4-cyclohexanedimethanol, polyalkylene glycol, polyethylene glycol, tetraethylene glycol, polytetramethylene ether glycol, etc.
• a preferred embodiment of the laminate film of the present invention is one in which the in-plane refractive index of at least one surface of the laminate film is 1.68 or more and 1.80 or less.
• the surface layer be a layer with relatively high crystallinity in consideration of ease of film formation, etc., but by having the in-plane refractive index of this surface layer be 1.68 or more, the in-plane refractive index difference with the layer with relatively low crystallinity can be made large. This makes it easy to make the laminate film have a reflection band of 100 nm or more with a reflectance of 30% or more.
• the in-plane refractive index of the surface layer be lower than 1.80, deterioration of the adhesion between the two alternating layers is suppressed, and clouding of the laminate film and peeling at the interface are reduced.
• the laminated film of the present invention has as its main component a crystalline polyester in which the A layer has naphthalenedicarboxylic acid units as the main structural unit.
• the reflectance at the surface of the A layer is high, and it is easy to create a refractive index difference with the B layer, so that a laminated film with better reflective performance can be obtained.
• “having naphthalenedicarboxylic acid units as the main structural unit” means that naphthalenedicarboxylic acid units account for more than 50 mol% and up to 100 mass% of all dicarboxylic acid structural units of the polyester resin.
• Naphthalenedicarboxylic acid which is a structural unit of the crystalline polyester resin of layer A, includes 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, etc., and 2,6-naphthalenedicarboxylic acid is particularly preferred.
• layer B is mainly composed of an amorphous thermoplastic resin, the more naphthalenedicarboxylic acid units there are in the crystalline polyester resin, which is the main component of layer A, the easier it is to increase the refractive index difference between layer A and layer B.
• the naphthalenedicarboxylic acid units in the dicarboxylic acid units of the crystalline polyester resin, which is the main component of layer A are more preferably 80 mol% or more and 100 mass% or less, and even more preferably 95 mol% or more and 100 mass% or less.
• the content of the crystalline polyester resin in layer A is preferably 80 mass% or more and 100 mass% or less, and more preferably 95 mass% or more and 100 mass% or less, when the entire layer is taken as 100 mass%.
• the difference in the in-plane refractive index between layers A and B is preferably 0.05 or more. It is more preferably 0.12 or more, and even more preferably 0.14 to 0.35. If the difference in the average in-plane refractive index is less than 0.05, it may be difficult to have a reflection band with a reflectance of 30% or more.
• One example of a method for achieving this is to make the main component of layer A a crystalline polyester resin and the main component of layer B an amorphous thermoplastic resin. In this case, it becomes possible to easily create a refractive index difference during the stretching and heat treatment steps in the production of the laminated film.
• the difference in the in-plane refractive index between layers A and B is preferable for the difference in the in-plane refractive index between layers A and B to be large, but to increase the difference in the in-plane refractive index requires that the chemical structures of the thermoplastic resin that is the main component of both layers be significantly different, which would result in poor interlayer adhesion.
• the difference in the average in-plane refractive index between layers A and B is 0.35 or less, lamination becomes easier and the heat resistance and handleability of the resulting laminated film are improved.
• TA is the highest glass transition temperature determined by differential scanning calorimetry (DSC measurement) and TX is the shrinkage start temperature determined from the TMA curve in the main orientation direction, and that TX is 5°C to 30°C lower than TA, in other words, TA-TX is 5°C to 30°C.
• the main orientation direction refers to the direction in the film plane with the greatest degree of molecular orientation, which can be identified by measurement with a known molecular orientation meter (details of the measurement method will be described later).
• the shrinkage start temperature can be measured by TMA measurement, and details of the measurement method will be described later. DSC measurement can be performed based on JIS-K-7121 (1987), and details of the measurement method will be described later.
• laminated films have interfaces formed from different thermoplastic resin layers, in addition to light scattering and diffuse reflection from the film surface, scattering and reflection from the interface are added, making unevenness more noticeable than films made of one type of resin. Therefore, if a laminated film that is less likely to cause unevenness can be used, the problem of poor appearance of molded products can be solved.
• pre-lamination process When laminating a laminated film with a support and an interlayer film to form the laminated film, it is common to first bond the laminated film and the interlayer film together at a low temperature (pre-lamination process (hereinafter sometimes referred to as pre-lamination process)), and then bond them to the support by applying pressure at a higher temperature (main pressure bonding process).
• pre-lamination process hereinafter sometimes referred to as pre-lamination process
• main pressure bonding process main pressure bonding process.
• the method of the pre-lamination process is not particularly limited, but it is common to sandwich the film between two interlayer films and roll laminate them at 90 to 100°C, which is a temperature slightly higher than the glass transition temperature of the polyester resin.
• the method of the main pressure bonding process is also not particularly limited, but it is common to sandwich the sheet after the pre-lamination process between supports such as glass and bond them in an autoclave (pressure-heating adhesion furnace) at 140 to 150°C for 20 to 30 minutes at a pressure of 12 to 14 kg/ cm2 .
• autoclave pressure-heating adhesion furnace
• the laminated film and interlayer film soften and shrink during the pre-lamination and final compression processes, and if their flexibility and shrinkage behavior differs significantly, it can cause air bubbles, wrinkles, and in-plane color unevenness. Therefore, it is required that the laminated film not only shrink during the final compression process, which is formed at a higher temperature, but also shrink at lower temperatures such as in the pre-lamination process, i.e., the shrinkage initiation temperature must be lower than the glass transition temperature.
• thermoplastic resin films are processed from a pellet state into a sheet by melt extrusion, and are then stretched and processed at a temperature higher than the glass transition temperature.
• the oriented crystals formed at a temperature higher than the glass transition temperature are relaxed by heating again, and shrinkage progresses rapidly.
• the shrinkage will be insufficient or excessive at the other temperature, resulting in air bubbles, wrinkles, and in-plane color unevenness.
• the present invention has discovered that the above problem can be solved by designing the laminated film so that shrinkage begins at a temperature 5°C to 30°C lower than the highest glass transition temperature (in other words, by setting TA-TX to 5°C to 30°C).
• the shrinkage start temperature calculated from the TMA curve in the main orientation direction is TX
• TX 5°C to 30°C lower than TA it is possible to suppress the occurrence of bubbles, wrinkles, and in-plane color unevenness, and to obtain a molded product with excellent appearance (particularly the appearance in the main orientation direction). From the above viewpoint, it is more preferable to make it 10°C to 30°C. If TA-TX exceeds 30°C, the laminated film becomes too flexible, which can lead to poor productivity and poor handling during molding. Furthermore, if TA-TX is less than 5°C, bubbles and wrinkles are more likely to occur, resulting in poor appearance.
• the laminate film of the present invention preferably has a difference between TY and TX of 0°C or more and 10°C or less, where TY is the shrinkage start temperature determined from the TMA curve in the direction perpendicular to the main orientation.
• TY is the shrinkage start temperature determined from the TMA curve in the direction perpendicular to the main orientation.
• the direction perpendicular to the main orientation refers to the direction perpendicular to the main orientation direction within the film plane.
• the "difference between TY and TX" is calculated as an absolute value.
• TY is preferably 5°C to 30°C lower than TA (in other words, TA-TY is 5°C to 30°C), and more preferably 10°C to 30°C.
• the method for making TX 5°C to 30°C lower than TA is not particularly limited, but for example, when obtaining a laminated film by successive biaxial stretching as described below, micro-stretching can be performed in the process of slowly cooling to room temperature after heat treatment following stretching in the width direction (TD). Alternatively, it is also effective to perform pseudo micro-stretching by increasing the tension (draw) in the winding process after slow cooling. In either case, micro-stretching at a temperature lower than the glass transition temperature makes it possible to obtain a film that shrinks at a temperature lower than the glass transition temperature. It is also effective to control the heat treatment temperature and the cooling temperature after heat treatment to a suitable range. Note that these methods can be combined as necessary.
• the laminated film of the present invention preferably has a heat shrinkage rate of 0.5% or more and 1.2% or less in at least one of the main orientation direction and the direction perpendicular to the main orientation in a TA atmosphere.
• a TA atmosphere refers to an environment where the temperature is TA.
• the heat shrinkage rate of at least one of the main orientation direction and the direction perpendicular to the main orientation is more preferably 0.7% or more and 1.2% or less, and even more preferably 0.9% or more and 1.2% or less.
• the laminated film of the present invention has a heat shrinkage rate of 0.5% or more and 1.2% or less in both the main orientation direction and the direction perpendicular to the main orientation, and the preferred range is also as described above.
• the heat shrinkage rate can be calculated by measuring the dimensional change after heat treatment, and the measurement method will be described in detail later.
• the thermal shrinkage rate in at least one of the main orientation direction and the direction perpendicular to the main orientation is 0.5% or more, air bubbles, wrinkles, and in-plane color unevenness are less likely to occur during the lamination process, especially the pre-lamination process.
• the shrinkage rate is 1.2% or less in at least one of the above directions, excessive flexibility of the laminated film is suppressed, resulting in good productivity and ease of handling during molding.
• the laminated film of the present invention preferably has a heat shrinkage rate in at least one of the main orientation direction and the direction perpendicular to the main orientation of 1.5% or more and less than 4.0%, more preferably 2.0% or more and less than 4.0%, and even more preferably 2.0% or more and less than 3.0%. From the above viewpoint, it is more preferable that the heat shrinkage rate in both the main orientation direction and the direction perpendicular to the main orientation of 1.5% or more and less than 4.0%, or within the above preferred range, in an atmosphere of 150°C.
• the heat shrinkage rate in at least one of the main orientation direction and the direction perpendicular to the main orientation is 1.5% or more in an atmosphere of 150°C, air bubbles, wrinkles, and in-plane color unevenness are less likely to occur during the lamination process, especially the main pressure bonding process.
• the heat shrinkage rate in at least one of the above directions is less than 4.0% in an atmosphere of 150°C, it is possible to reduce the deterioration of productivity and handling during molding processing, the occurrence of color unevenness, and deterioration of appearance due to excessive flexibility of the laminated film.
• the thermal shrinkage rate in at least one of the main orientation direction and the direction perpendicular to the main orientation 1.5% or more and less than 4.0% in an atmosphere of 150°C, methods of adjusting the stretching ratio and heat treatment temperature can be mentioned. More specifically, the thermal shrinkage rate can be increased by increasing the stretching ratio of the film or by decreasing the heat treatment temperature after stretching in the width direction. These methods can also be used in combination as appropriate.
• the in-plane stretching ratio is preferably 11.0 times or more and 18.0 times or less, and more preferably 12.0 times or more and 18.0 times or less. From the above viewpoint, it is preferable that the longitudinal stretching ratio is 3.0 times or more and 3.8 times or less, and the transverse stretching ratio is 3.7 times or more and 4.2 times or less.
• the in-plane stretching ratio is 11.0 times or more, it becomes easy to set the thermal shrinkage rate in each direction in an atmosphere of 150°C to 1.5% or more and less than 4.0%.
• the in-plane stretching ratio is 18.0 times or less, whitening during film formation due to excessive stretching and a decrease in productivity due to film breakage are suppressed.
• the laminated film of the present invention follows the shrinkage of the interlayer film in both the pre-lamination process and the final pressure bonding process, making it less likely to produce air bubbles, wrinkles, and in-plane color unevenness.
• the ratio of the high-temperature heat shrinkage rate in the final pressure bonding process to the heat shrinkage rate at the glass transition temperature of the film used affects air bubbles, wrinkles, and in-plane color unevenness.
• the maximum temperature for the final pressure bonding process is generally 150°C, so if the heat shrinkage rate at the temperature at which the film shrinks the most is significantly different from or too close to the heat shrinkage rate at the glass transition temperature, it becomes difficult to follow the shrinkage of the interlayer film in both the pre-lamination process and the final pressure bonding process.
• the laminated film of the present invention has an S(150)/S(TA) ratio of 1.5 or more and 5.0 or less, where S(150) is the average heat shrinkage at 150°C and S(TA) is the average heat shrinkage at TA.
• S(150)/S(TA) is more preferably 1.5 or more and 4.0 or less, and even more preferably 1.5 or more and 3.0 or less.
• S(150) refers to the average value of the heat shrinkage in the main orientation direction and the heat shrinkage in the direction perpendicular to the main orientation at 150°C
• S(TA) and S(120) described below can be interpreted in the same way, except that the temperature changes from 150°C to TA or 120°C. If S(150)/S(TA) is 5.0 or less, air bubbles, wrinkles, and in-plane color unevenness caused by an excessively high heat shrinkage rate at 150°C of the laminated film or an excessively small heat shrinkage at the glass transition temperature (TA) are suppressed. If S(150)/S(TA) is 1.5 or more, the film follows the shrinkage of the interlayer film in both the pre-lamination process and the main pressure bonding process when glass is used as the support, reducing the occurrence of air bubbles and wrinkles.
• S(120)/S(TA) is 1.5 or more and 5.0 or less. From the above viewpoint, S(120)/S(TA) is more preferably 1.5 or more and 3.0 or less, and even more preferably 1.5 or more and 2.0 or less.
• S(120)/S(TA) When S(120)/S(TA) is 5.0 or less, bubbles, wrinkles, and in-plane color unevenness caused by an excessively high heat shrinkage rate at 120°C of the laminated film or an excessively small heat shrinkage at the glass transition temperature (TA) are suppressed. If S(120)/S(TA) is 1.5 or more, it follows the shrinkage of the interlayer film in both the pre-lamination process and the main pressure bonding process when a resin such as acrylic or polycarbonate is used as the support, reducing the occurrence of air bubbles and wrinkles.
• a resin such as acrylic or polycarbonate
• thermoplastic resin A thermoplastic resin A, thermoplastic resin B
• thermoplastic resin B thermoplastic resin B
• the method for lowering the glass transition temperature Tg of a thermoplastic resin is not particularly limited, but examples include a method of copolymerizing a component with low crystallinity with a thermoplastic resin and a method of using a thermoplastic resin with a low glass transition temperature.
• the glass transition temperature of polyethylene naphthalate (PEN) which is the most commonly used polyester containing naphthalenedicarboxylic acid as a dicarboxylic acid component, is about 120°C.
• PEN polyethylene naphthalate
• thermoplastic resin such as polyethylene terephthalate
• a glass transition temperature lower than 105°C is exemplified.
• the low-crystalline structural unit to be copolymerized is not particularly limited as long as it is a structural unit with lower crystallinity than the main structural unit, but in the case of a polyester resin, it is preferable that the structural unit is derived from a compound containing a chemical structure represented by the following formula (3). That is, when the thermoplastic resin A or the thermoplastic resin B is a polyester resin, it is preferable to copolymerize the chemical structure represented by formula (3) in order to lower the glass transition temperature.
• a mixture in which a thermoplastic resin containing a structural unit represented by the following formula (3) is mixed in the A layer or the B layer may be used.
• m and n represent natural numbers such that m ⁇ n is 5 or more. -O-(C n H 2n -O) m - ...Formula (3).
• thermoplastic resin components constituting each layer are unknown, the presence or absence of the chemical structure represented by formula (3) can be confirmed, for example, by the following method.
• a weight peak is confirmed by gas chromatography mass spectrometry (GC-MS).
• FT-IR Fourier transform infrared spectroscopy
• the position of the chemical shift derived from the position of a hydrogen atom or carbon atom in the chemical structural formula and the proton absorption line area derived from the number of hydrogen atoms are confirmed by proton nuclear magnetic resonance spectroscopy ( 1 H-NMR, 13 C-NMR). From these results, the presence or absence of the chemical structure represented by formula (3) can be determined.
• m ⁇ n in formula (3) is preferably 6 or more, and more preferably 8 or more.
• Specific examples of compounds having the chemical structure represented by formula (3) include polyethylene glycol, tetraethylene glycol, polytetramethylene ether glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, tetrapropylene glycol, tributylene glycol, tetrabutylene glycol, etc.
• the copolymerized polyester resin preferably contains 0.5 mol% to 40 mol% of structural units having a chemical structure represented by formula (3) relative to 100 mol% of all diol constituents.
• the diol units of formula (3) are contained within this range, it becomes easy to set the glass transition temperature of thermoplastic resin A and thermoplastic resin B to 105°C or less. Note that when the diol units of formula (3) are contained in both thermoplastic resin A and thermoplastic resin B by copolymerization, the amount can be appropriately adjusted within the above range, taking into consideration crystallinity as well as glass transition temperature.
• thermoplastic resin A is a PEN copolymer and thermoplastic resin B is a PET copolymer
• the content of the diol unit of formula (3) is preferably 3 mol% to 20 mol% in thermoplastic resin A relative to 100 mol% of all diol constituents, and 3 mol% to 20 mol% in thermoplastic resin B relative to 100 mol% of all diol constituents.
• a compound having a chemical structure represented by formula (3) may be contained in at least one of layer A and layer B. In this case, it is preferable to adjust the amount of the compound to 0.5 mol % or more and 40 mol % or less with respect to 100 mol % of all diol constituents of all polyester resins constituting layer A or layer B. Even when the compound structure represented by formula (3) is obtained by mixing, the same effect as when the glass transition temperature is lowered by copolymerization can be obtained.
• layers A and B to contain the chemical structure represented by formula (3) by copolymerization in thermoplastic resin A or thermoplastic resin B rather than mixing the compounds.
• copolymerizing a diol component having the chemical structure represented by formula (3) in thermoplastic resin A or thermoplastic resin B is also preferable in that it can prevent components having these chemical structures from leaking out of the laminate film system due to evaporation or sublimation.
• polyester resins with a lower glass transition temperature include dicarboxylic acid components such as terephthalic acid, isophthalic acid, phthalic acid, adipic acid, sebacic acid, dimer acid, cyclohexanedicarboxylic acid, and their ester-forming derivatives.
• diol components include the same components as those mentioned above, with ethylene glycol, 1,4-cyclohexanedimethanol, and 1,4-butanediol being particularly preferred.
• the laminate film of the present invention preferably has an internal haze of 0.5% or less.
• Internal haze is an index that indicates the haze (turbidity) inside the film excluding light scattering on the film surface.
• the internal haze of the laminate film is preferably 0.4% or less, and more preferably 0.3% or less.
• the internal haze of the laminate film can be measured by measuring the haze in accordance with JIS-K-7105 (1981) while the film is placed in a quartz cell filled with liquid paraffin (details of the measurement method will be described later).
• the type and amount of components other than thermoplastic resin A in layer A and the type and amount of components other than thermoplastic resin B in layer B can be adjusted.
• the internal haze can be reduced by appropriately combining thermoplastic resin A and thermoplastic resin B.
• thermoplastic resin A and thermoplastic resin B are a combination of polyethylene naphthalate resin copolymerized with polyethylene glycol as thermoplastic resin A and polyethylene terephthalate resin copolymerized with cyclohexane dimethanol as thermoplastic resin B. Furthermore, the internal haze can be reduced by reducing the number of resin layers and the thickness of the film.
• the average reflectance of P waves of wavelengths of 400 to 700 nm at an incidence angle of 60° is 10% or more and 50% or less.
• the incidence angle is gradually increased from 20° to the normal to the film surface, the reflectance of P waves, which are one type of polarized light, decreases, and the reflectance becomes 0% at an angle called Brewster's angle.
• the Brewster's angle varies depending on the refractive index of the material, and is about 60° in the case of polyester resin. Therefore, general transparent substrates transmit P waves from the front direction and have difficulty reflecting P waves from oblique directions.
• the incidence angle refers to the angle between the normal to the film surface and the traveling direction of the light ray.
• an embodiment in which the average reflectance of P waves of wavelengths 400 to 700 nm at an incident angle of 60° is 10% or more and 50% or less is an embodiment that does not have an angle equivalent to Brewster's angle. Therefore, by adopting such an embodiment, it is possible to reflect P waves that are incident on the film surface from an oblique direction.
• the average reflectance of P waves of wavelengths 400 to 700 nm at an incident angle of 60° is 10% or more, the display quality of the projected image when an image by P waves is projected onto the laminated film is improved.
• the average reflectance of P waves at an incident angle of 60° is preferably 20% or more, and more preferably 25% or more.
• the average reflectance of P waves of incident angle 60° being 50% or less, it is possible to suppress the average reflectance of P waves of incident angle 20° to 50° from increasing as the average reflectance of P waves of incident angle 60° is increased. Therefore, glare of the projected image by P waves is reduced, and the display quality is improved.
• the absolute value of the difference in the surface normal refractive index between layers A and B be 0.11 or more and 0.20 or less, and more preferably 0.13 or more and 0.20 or less.
• the absolute value of the difference in the surface normal refractive index between layers A and B is 0.11 or more, the display quality of the projected image described below is improved. On the other hand, if this difference is kept to 0.20 or less, peeling at the interface between layers A and B is reduced.
• a method can be used in which the refractive index difference between the two thermoplastic resin layers in the direction perpendicular to the film surface and the number of layers are adjusted.
• the greater the refractive index difference in the direction perpendicular to the film surface and the greater the number of layers the greater the average P-wave reflectance at an incident angle of 60° can be.
• the difference in the perpendicular refractive index between layers A and B can be determined by adjusting the composition of the resin constituting each layer and the film-making conditions (e.g., stretching ratio, stretching speed, stretching temperature, heat treatment temperature, heat treatment time).
• the perpendicular refractive index refers to the refractive index in the direction perpendicular to the multilayer laminated film surface.
• the composition of the resin constituting layers A and B can be the composition of thermoplastic resin A and thermoplastic resin B described above, but it is preferable to use polyethylene terephthalate as thermoplastic resin A and polyethylene terephthalate as thermoplastic resin B, in which 2,6-naphthalenedicarboxylic acid is copolymerized at 15 mol% to 35 mol% of the total dicarboxylic acid components.
• the laminate film of the present invention which has an average P-wave reflectance of 10% to 50% for wavelengths of 400 to 700 nm at an incident angle of 60°, preferably has an average transmittance of 50% to 100% for wavelengths of 400 to 700 nm at an incident angle of 10°.
• This high average transmittance of light in the visible light region of 400 to 700 nm wavelengths gives the film transparency similar to that of transparent glass or transparent resin film, and good visibility of the background can be obtained when the background is observed through the laminate film from a direction perpendicular to the laminate film surface.
• the average transmittance is preferably 70% or more, more preferably 80% or more, and even more preferably 85% or more. If the average transmittance is 85% or more, the user can see the background without feeling the presence of the laminated film. From the viewpoint of feasibility, the upper limit of the average transmittance is preferably 99%.
• Such a laminated film can be obtained by reducing the refractive index difference between the two thermoplastic resin layers in the direction parallel to the film surface.
• the transmittance can be easily increased to 50% or more, if it is 0.04 or less, the transmittance can be increased to 70% or more, and if it is 0.02 or less, the transmittance can be increased to 80% or more.
• the "refractive index difference in the direction parallel to the film surface" refers to the absolute value of the difference in in-plane refractive index between the A layer and the B layer.
• thermoplastic resin A layer A
• thermoplastic resin B layer B
• the present invention is not limited to this example.
• the formation of the laminated structure of the laminated film itself can be realized by referring to the description in paragraphs [0053] to [0063] of JP 2007-307893 A.
• the same can be interpreted for a laminated film consisting of three types of layers, including layer C.
• Thermoplastic resin A and thermoplastic resin B are prepared in the form of pellets or the like. If necessary, the pellets are dried in hot air or under vacuum, and then fed to separate extruders. In the extruder, thermoplastic resin A is heated and melted at a temperature above its melting point, and thermoplastic resin B is heated and melted at a temperature within the range of the heating temperature of thermoplastic resin A ⁇ 30°C so that no uneven extrusion occurs. Next, the extrusion amount is made uniform using a gear pump or the like, and the molten thermoplastic resin is extruded, and foreign matter and denatured resin are removed through a filter or the like.
• thermoplastic resins are laminated in the desired layer configuration using a lamination device, formed into the desired sheet shape using a die, and then discharged onto a casting drum.
• the multi-layered molten sheet discharged from the die is then extruded onto a cooling body such as a casting drum, cooled and solidified, and a casting film is obtained.
• a wire-shaped, tape-shaped, needle-shaped, or knife-shaped electrode to adhere to a cooling body such as a casting drum by electrostatic force and rapidly solidify.
• the lamination device As the lamination device, a multi-manifold die, a feed block, a static mixer, etc. can be used, but in order to efficiently obtain the configuration of the present invention, it is preferable to use a feed block that includes at least two or more separate members with many fine slits.
• a feed block that includes at least two or more separate members with many fine slits.
• the device does not become extremely large, so there is less foreign matter due to thermal degradation, and high-precision lamination is possible even when the number of layers is extremely large.
• the lamination precision in the width direction is also significantly improved compared to conventional technology.
• the thickness of each layer can be adjusted by the shape (length, width) of the slits, making it easy to achieve any layer thickness.
• biaxial stretching refers to stretching in the longitudinal direction and the width direction. Stretching may be performed in the two directions sequentially, or simultaneously in the two directions. Furthermore, re-stretching may be performed in the longitudinal direction and/or the width direction.
• the longitudinal direction refers to the running direction of the film
• the width direction refers to the direction perpendicular to the longitudinal direction within the film plane.
• stretching in the longitudinal direction refers to stretching to give the film a longitudinal molecular orientation, and is usually performed by the difference in peripheral speed of the rolls. This stretching may be performed in one stage, or in multiple stages using multiple pairs of rolls.
• the stretching ratio varies depending on the type of resin, but is usually preferably 2.0 to 9.0 times.
• 2.0 to 7.0 times is preferably used.
• the longitudinal stretching ratio is particularly preferably 3.0 times or more and 3.8 times or less.
• the stretching temperature is preferably in the range of the glass transition temperature of the resin with the higher glass transition temperature among the resins constituting the laminated film to the glass transition temperature + 100°C.
• the uniaxially stretched film thus obtained may be subjected to surface treatment such as corona treatment, flame treatment, or plasma treatment as necessary, and then properties such as easy slippage, easy adhesion, and antistatic properties may be imparted by in-line coating.
• widthwise stretching refers to stretching to give a widthwise orientation to a film, and is usually used to stretch a uniaxially stretched film in the width direction by conveying the film while holding both ends with clips using a tenter.
• the stretching ratio varies depending on the type of resin, but is usually preferably 2.0 to 9.0 times.
• a ratio of 2.0 to 7.0 times is preferably used.
• the transverse stretching ratio is particularly preferably 3.7 times or more and 4.2 times or less.
• the in-plane stretching ratio which is the product of the longitudinal stretching ratio and the transverse stretching ratio, is preferably 11.0 times or more and 18.0 times or less, and more preferably 12.0 times or more and 18.0 times or less.
• the stretching temperature is preferably in the range of the glass transition temperature of the resin with the higher glass transition temperature among the resins that make up the laminated film to the glass transition temperature + 120°C.
• the biaxially stretched film thus obtained is preferably heat-treated in a tenter at a temperature equal to or higher than the stretching temperature and equal to or lower than the melting point of thermoplastic resin A in order to impart flatness and dimensional stability.
• the dimensional stability of the resulting laminated film is improved.
• the laminated film is preferably uniformly cooled slowly at a temperature equal to or higher than the glass transition temperature of thermoplastic resin A and lower than the heat treatment temperature. More specifically, it is preferable to slowly cool the film at a temperature higher than 100°C and equal to or lower than 200°C, more preferably between 130°C and 180°C, and even more preferably between 150°C and 180°C. After being slowly cooled, the film is cooled to room temperature and wound up. In addition, 0.1% to 10% additional stretching or relaxation treatment may be used in combination with the heat treatment and slow cooling.
• the heat treatment temperature after stretching is below the melting point of thermoplastic resin A and above the melting point of thermoplastic resin B.
• thermoplastic resin A maintains a high orientation state while the orientation of thermoplastic resin B is relaxed, so that a refractive index difference can be easily established between each layer (layer A, layer B) containing these resins as main components.
• the heat treatment temperature is preferably below the melting point of the crystalline resin and in the range of the glass transition temperature of the crystalline resin to the glass transition temperature + 120°C.
• thermoplastic resin A and thermoplastic resin B are a crystalline polyester having naphthalenedicarboxylic acid units as the main structural unit
• the heat treatment temperature is preferably 170°C or more and less than 220°C, more preferably 175°C or more and 215°C or less, even more preferably 175°C or more and 210°C or less, and particularly preferably 175°C or more and 200°C or less.
• the heat treatment step is not necessary.
• the obtained cast film may be subjected to surface treatment such as corona treatment, frame treatment, plasma treatment, etc. as necessary, and then properties such as easy slip, easy adhesion, and antistatic properties may be imparted by in-line coating.
• simultaneous biaxial stretching machines include pantograph type, screw type, drive motor type, and linear motor type, but drive motor type or linear motor type is preferred because it allows the stretching ratio to be changed at any desired location and allows relaxation treatment to be performed at any desired location.
• the stretching ratio varies depending on the type of resin, but usually, an area ratio of 6.0 to 30.0 times is preferred, and when a polyethylene naphthalate copolymer resin is used as one of the resins constituting the laminated film, an area ratio of 9.0 to 18.0 times is particularly preferred.
• the stretching temperature is preferably in the range of the glass transition temperature of the resin with the higher glass transition temperature among the resins constituting the laminated film to the glass transition temperature + 120°C.
• the film thus biaxially stretched is then heat-treated, slowly cooled, and cooled to room temperature, as in the case of sequential biaxial stretching, and then wound up.
• the heat treatment in order to suppress the distribution of the main orientation axis in the width direction, it is preferable to instantly relax the film in the longitudinal direction immediately before and/or after it enters the heat treatment zone.
• the laminate of the present invention comprises a support 1, an intermediate layer 1, the laminate film of the present invention, an intermediate layer 2, and a support 2 in this order.
• the laminated glass of the present invention is one in which both the support 1 and the support 2 are glass.
• the laminate and laminated glass of the present invention may comprise a plurality of the above-mentioned members, and other members may be present between the above-mentioned members, as long as the above-mentioned members are arranged in this order.
• the support 1 and the support 2 may be the same member or different members, and the same applies to the intermediate layer 1 and the intermediate layer 2.
• Such molded bodies and laminated glass are excellent in terms of strength, and in particular, laminated glass has a feature of suppressing glass shattering and penetration of objects when an object hits the glass surface, compared to paired glass (multiple-layered glass) with an air layer between two pieces of glass. Therefore, the laminated glass of the present invention is suitable for use in applications requiring safety and crime prevention, such as window glass for automobiles and buildings.
• the laminated glass by providing the laminated glass with the laminated film of the present invention, it is possible to impart functions such as a heat ray cutting function, a half mirror function, and a color filter function to the laminated glass.
• the laminate using the laminate film of the present invention comprises support 1, intermediate layer 1, the laminate film of the present invention, intermediate layer 2, and support 2 in this order.
• Support 1 and support 2 play a role in increasing the strength of the laminate.
• supports for obtaining the laminate of the present invention include resin, metal, glass, ceramic, etc.
• the surface of the support may be flat or curved, and may have any shape.
• resins used for supports 1 and 2 include acrylic resins such as polycarbonate, cyclic polyolefin, polyarylate, polyethylene terephthalate, and polymethyl methacrylate, ABS resin, triacetyl cellulose, etc.
• glass used for supports 1 and 2 include float glass, tempered glass, colored glass, and heat-shielding glass. If supports 1 and 2 are assumed to be used for heat reflection applications or as projection components for head-up displays, they are preferably transparent, and the thickness of the support is preferably 0.05 mm to 5 mm from the viewpoint of ensuring strength and reducing weight at the same time.
• the intermediate layers 1 and 2 serve to bond the laminated film of the present invention to the support 1 or 2, and are preferably an adhesive layer or a film layer.
• adhesives include vinyl acetate resins, vinyl chloride-vinyl acetate copolymers, ethylene-vinyl acetate copolymers, polyvinyl alcohol, polyvinyl butyral, polyvinyl acetal, polyvinyl ether, nitrile rubbers, styrene-butadiene rubbers, natural rubbers, chloroprene rubbers, polyamides, epoxy resins, polyurethanes, acrylic resins, cellulose, polyvinyl chloride, polyacrylic esters, polyisobutylene, and the like.
• adhesion regulators plasticizers, heat stabilizers, antioxidants, UV absorbers, antistatic agents, lubricants, colorants, crosslinking agents, and the like may be added to these adhesives.
• a method for improving the design of the laminate is to add a colorant to the intermediate layer.
• colorants include azo pigments, polycyclic pigments, lake pigments, nitro pigments, nitroso pigments, aniline black, alkali blue, phthalocyanine pigments, cyanine pigments, azo dyes, anthraquinone dyes, quinophthalone dyes, methine dyes, condensed polycyclic dyes, reactive dyes, cationic dyes, lanthanum hexaboride, indium tin oxide, antimony tin oxide, and cesium tungsten oxide.
• the thickness of the intermediate layer is preferably 10 ⁇ m to 1 mm.
• Forming methods for obtaining laminates include extrusion lamination, hot melt lamination, thermal lamination, press lamination, vacuum lamination, autoclave lamination, etc.
• Extrusion lamination is a method in which the molten resin composition for obtaining the laminate film and intermediate layer is extruded from a die into a film shape, laminated onto a support, and molded by passing the molded product between two rolls.
• Hot melt lamination is a molding method in which a resin composition for forming an intermediate layer that has been melted by heat is applied to the laminate film or support, and the laminate film and support are laminated.
• Thermal lamination is a molding method in which the laminate film, the sheet for the intermediate layer, and the support are heated and pressed together with a heating roll to laminate them.
• Press lamination is a molding method in which the laminate film, the sheet for the intermediate layer, and the support are heated and pressed together with a press machine to laminate them.
• Vacuum lamination is a molding method in which the laminate film, the sheet for the intermediate layer, and the support are heated, and then the inside of the device is made into a vacuum state, and they are pressed and laminated.
• Autoclave lamination is a lamination method in which the laminated film, intermediate layer sheet, and support are heated, and then the inside of the device is pressurized with gas or other means to laminate them.
• the laminate film of the present invention will be described in more detail below using examples. However, the laminate film of the present invention is not limited to the embodiments shown below.
• Layer thickness, number of layers, and layer structure The layer structure and number of layers of the laminated film were identified and the thickness of each layer was measured by observing a sample cut from a cross section using a microtome and observing it with a transmission electron microscope (TEM) and measuring its length. Specifically, a transmission electron microscope H-7100FA (manufactured by Hitachi, Ltd.) was used to observe the cross section of the film at 10,000 to 40,000 times magnification under an acceleration voltage of 75 kV, and a cross-sectional photograph was taken to identify the layer structure and number of layers, and to measure the thickness of each layer. In some cases, a known staining technique using RuO4 or OsO4 was used to increase the contrast between layers.
• RuO4 or OsO4 was used to increase the contrast between layers.
• the sample was placed in front of the integrating sphere with the longitudinal direction facing up and down.
• the average transmittance for wavelengths from 400 to 700 nm was determined by averaging all the transmittances for every 1 nm. Measurements were taken on both sides of the sample, and the measurement result for the side with the higher average transmittance for wavelengths from 400 to 700 nm was used.
• the laminated film sample size was set to 10 cm x 10 cm, and a sample was cut out at the center in the width direction of the film.
• the orientation degree was measured using a molecular orientation meter MOA-2001 manufactured by KS Systems Co., Ltd. (now Oji Scientific Instruments Co., Ltd.), and the direction with the largest orientation degree was determined as the main orientation direction.
• the shrinkage start temperature TX was taken as 40°C, and if there were multiple temperatures at which the value changed from a positive value to a negative value, the lowest temperature was taken as the shrinkage start temperature TX. This measurement was performed five times, and the average value was adopted as the shrinkage start temperature TX.
• the shrinkage start temperature TY was similarly measured by cutting out a sample into a rectangular shape of 40 mm in the direction perpendicular to the main orientation direction (measurement direction) and 4 mm in the main orientation direction.
• the measurement directions were the main orientation direction and the direction perpendicular to the main orientation, the number of n was 3 in each direction, and the average value was adopted as the value of the thermal shrinkage.
• Heat shrinkage rate (%) 100 ⁇ (A ⁇ B)/A...Equation (4).
• In-plane refractive index of surface (A layer) The in-plane refractive index of the surface layer (A layer) was measured under the following measurement conditions using "SPA-4000" manufactured by SAIRON TECHNOLOGY, INC. The average value of the refractive index in the main orientation direction and the direction perpendicular to the main orientation direction of the laminated polyester film sample was taken as the in-plane refractive index.
• the main orientation direction was specified by the method of (7), and the direction perpendicular to the main orientation direction was taken as the direction perpendicular to the main orientation direction in the film plane.
• In-plane refractive index of layer B Since layer B is an inner layer of the laminated film, the in-plane refractive index was measured not on the film itself, but on a monolayer film of layer B produced under the same stretching and heat treatment conditions as the film, using a SPA-4000 manufactured by SAIRON TECHNOLOGY, INC. under the following measurement conditions. However, unlike the resin of layer A, the resin of layer B is amorphous, and the degree of orientation does not change due to stretching, and there is no main orientation direction. Therefore, the average value of the refractive index in the longitudinal direction and the refractive index in the width direction of the monolayer film was taken as the in-plane refractive index.
• the projection image display member was placed so that the light from the light source was incident at an angle of 60° with respect to the normal direction of the projection image display member surface, and an image was projected from the light source onto the projection image display member using P waves or S waves. After that, the display quality of the projected image was evaluated by visual inspection. (Evaluation criteria for display quality of projected images) S: The projected image was very bright. A: The projected image was bright. C: The projected image was dark.
• PEN(1) Polyethylene 2,6-naphthalate copolymerized with 4 mol % of polyethylene glycol having an average molecular weight of 400 based on the total diol constituents (intrinsic viscosity: 0.64, melting point: 260° C., glass transition temperature: 104° C.).
• PEN(2) Polyethylene 2,6-naphthalate copolymerized with 6 mol % of polyethylene glycol having an average molecular weight of 400 based on the total diol constituents (intrinsic viscosity: 0.64, melting point: 255° C., glass transition temperature: 97° C.).
• PET (2) Polyethylene terephthalate (intrinsic viscosity: 0.65, melting point: 254°C, glass transition temperature: 78°C).
• PET (1) A mixture of polyethylene terephthalate resin (intrinsic viscosity: 0.73, amorphous resin (no melting point), glass transition temperature: 79°C) copolymerized with 31 mol% cyclohexanedimethanol (CHDM) based on all diol constituents and polyethylene terephthalate (manufactured by Toray Industries, Inc., intrinsic viscosity: 0.65, melting point: 256°C, glass transition temperature: 80°C) in a mass ratio of 82:18 (melting point: 225°C, glass transition temperature: 79°C).
• CHDM cyclohexanedimethanol
• PET (3) Polyethylene terephthalate resin copolymerized with 30 mol % of 2,6-naphthalenedicarboxylic acid relative to all dicarboxylic acid constituents (intrinsic viscosity: 0.67, no melting point, glass transition temperature: 95° C.).
• Example 1 PEN (1) was used as the polyester resin (thermoplastic resin A) forming the A layer, and PET (1) was used as the polyester resin (thermoplastic resin B) forming the B layer.
• the polyester resins forming each layer were melted at 280 ° C. in a vented twin-screw extruder, and then merged in a 449-layer feed block via a gear pump and a filter, and 449 layers of the molten thermoplastic resin A and thermoplastic resin B were laminated alternately in the thickness direction so that the outermost layers on both sides were layers A.
• the resulting molten laminate was then guided to a T-die to be formed into a sheet and discharged, and the molten sheet-like material was quenched and solidified on a casting drum with a surface temperature of 25 ° C. by electrostatic application to obtain a cast film.
• the discharge amount was adjusted so that the mass ratio of thermoplastic resin A to thermoplastic resin B was about 1:1.
• the obtained cast film was heated with a group of rolls set at a temperature of the glass transition temperature of thermoplastic resin A + 10 ° C., and then stretched 3.2 times in the longitudinal direction (longitudinal direction) while rapidly heating from both sides with a radiation heater within a stretching section length of 100 mm, and then cooled once.
• both sides of this uniaxially stretched film were subjected to a corona discharge treatment in air to set the wet tension to 55 mN / m, and a lamination forming film coating liquid consisting of (polyester resin with a glass transition temperature of 18 ° C.) / (polyester resin with a glass transition temperature of 82 ° C.) / silica particles with an average particle size of 100 nm was applied to both sides to form a transparent, easy-to-adhere layer having easy slip properties.
• a lamination forming film coating liquid consisting of (polyester resin with a glass transition temperature of 18 ° C.) / (polyester resin with a glass transition temperature of 82 ° C.) / silica particles with an average particle size of 100 nm was applied to both sides to form a transparent, easy-to-adhere layer having easy slip properties.
• This uniaxially stretched film was guided to a tenter by holding both ends in the width direction with clips, preheated with hot air at 100 ° C., and then stretched 4.0 times in the transverse direction (width direction) at a uniform stretching speed at a temperature of the glass transition temperature of thermoplastic resin A + 20 ° C. Furthermore, in the same tenter, the stretched film was heat-treated with hot air at 195°C, and then subjected to 1% relaxation treatment in the width direction at the same temperature, followed by 1% additional stretching in the width direction in a cooling zone at a temperature of 150°C, and then slowly cooled to room temperature and wound up. The winder draw was 98%.
• the winder draw is the ratio of the tenter speed to the winder winding speed, and a winder draw of 98% indicates that the tenter speed is 2% slower than the winder winding speed.
• the thickness of the obtained laminated film was 90 ⁇ m. The evaluation results are shown in Tables 2-1, 2-2, 4-1, and 4-2.
• Examples 2 to 17, Comparative Examples 1 to 7 Except for changing the resin used in each layer, the number of layers, the film-forming conditions, and the thickness as shown in Tables 1, 2-1, 2-2, 3, 4-1, and 4-2, laminated films were produced under the same conditions as in Example 1. The evaluation results of the obtained laminated films are shown in Tables 2-1, 2-2, 4-1, and 4-2. The number of layers was adjusted by adjusting the number of slits in the feed block, and the thickness was adjusted by changing the speed of the entire film-forming line linked to the casting drum speed.
• the present invention can be used in decorative materials such as decorative panels, various home appliances, building materials, automobile-related parts, etc., and can be particularly used as heat-blocking glass that can suppress the inflow of heat caused by sunlight.

Landscapes

• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Laminated Bodies (AREA)

Priority Applications (2)

Applications Claiming Priority (2)

Publications (1)

Family

ID=95021309

Family Applications (1)

Country Status (3)

Citations (12)

• 2024
  • 2024-09-06 CN CN202480054979.2A patent/CN121752433A/zh active Pending
  • 2024-09-06 WO PCT/JP2024/032001 patent/WO2025057870A1/ja active Pending
  • 2024-09-06 JP JP2024554841A patent/JP7848887B2/ja active Active

Patent Citations (12)

Also Published As

Similar Documents

Legal Events