JP2005254472A - Hard coat multilayered sheet, building window glass using it and flat panel display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hard coat multilayered sheet excellent in adhesiveness, high surface hardness abrasion resistance, suppressed in the occurrence of an iris pattern and excellent in visibility and mechanical strength in the lamination of a base material multilayered sheet and a hard coat layer. <P>SOLUTION: The hard coat multilayered sheet is composed of the base material multilayered sheet (a) having a laminated structure and the hard coat layer (b). The base material multilayered sheet (a) has at least two layers, that is, a layer based on a polyester (A) and a layer based on a polyester (B). The average swell amplitude of the reflectivity of the hard coat layer (b) at the time of irradiation with light with a wavelength of 400-660 nm is 1% or below. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a hard coat multilayer sheet. More specifically, the surface hardness is high and the wear resistance is excellent. At the same time, the occurrence of an iris pattern is suppressed and the visibility is excellent, and the adhesion between the hard coat layer and the substrate is excellent. The present invention relates to a hard coat multilayer sheet using a multilayer sheet having a hard coat layer and excellent mechanical properties as a substrate.

  Base sheet, especially biaxially oriented polyester sheet, has excellent properties such as mechanical properties, dimensional stability, heat resistance, transparency and electrical insulation, so that it can be used for magnetic recording materials, packaging materials, and electrical insulation materials. It is widely used as a base material sheet for many uses such as various photographic materials, graphic art materials, optical display materials (for example, antireflection sheets and touch panel sheets), window covering sheets and nameplate sheets. However, depending on the application, such a base sheet has a low surface hardness and lacks abrasion resistance, so that the surface is easily damaged by contact with other hard substances, friction or scratches, etc. The damage generated on the surface significantly reduces the commercial value or becomes unusable in a short period of time. Furthermore, as a requirement for the base material, it is desired to maintain dimensional stability, heat resistance, transparency, electrical insulation, and the like, and to further improve mechanical properties.

  About glass, it is used for various uses from the outstanding light transmittance, gas barrier property, dimensional stability, etc. Higher performance glass is provided in the field of flat displays represented by buildings and automobiles, particularly flat CRT displays, liquid crystal displays, plasma displays, organic EL displays, field emission displays and the like.

  However, a drawback of glass is that it is easily broken or glass is scattered by breakage. This problem is remarkable in the field of flat displays. The flat display has a problem that the display glass itself tends to be thin due to demands for thinning and weight reduction, and accordingly, there is a problem that the flat display is easily broken during use.

  Various methods have been proposed for preventing such problems of glass breakage and glass scattering caused by breakage by attaching a film made of a thermoplastic resin to the glass.

  Furthermore, for example, in the case of a base material sheet made of a polyester sheet, a method is known in which a hard coat layer having excellent scratch resistance and abrasion resistance is provided thereon. However, the normal polyester sheet has poor adhesion to the hard coat layer because the surface is highly crystallized, and the hard coat layer peels off from the base sheet, which is substantially inferior in durability. have. For this reason, conventionally, studies have been made on imparting adhesion to the surface of the polyester film by various methods.

  Conventionally, as a method for imparting adhesiveness to a polyester sheet, a surface activation method using corona treatment, ultraviolet irradiation treatment or plasma treatment on the surface of a polyester base film, a surface etching method using a chemical such as an acid, alkali or aqueous amine solution, and A method of providing various resins such as an acrylic resin, a sulfonate group-containing polyester resin, or a urethane resin on the film surface as a primer layer (see Patent Documents 1 to 3) is already known. In particular, in the method of providing a primer layer on a base film by coating, a coating liquid containing the resin component is applied to a polyester base film before crystal orientation is completed, dried, and then subjected to stretching and heat treatment. A method of completing crystal orientation (in-line coating method) is considered promising in terms of process simplification and manufacturing cost, and is being actively performed.

  In addition, a polyester-based resin laminate film (see Patent Document 4) in which an adhesive layer made of two types of polyester resins copolymerized with a softening component is laminated by a coextrusion method or the in-line coating method described above, and urethane on the polyester film surface. A method of providing a coating layer made of resin and providing a hard coat layer thereon (see Patent Document 5) has also been proposed.

In addition, the hard coat layer thus provided often has a refractive index different from that of the polyester base material or primer layer, and there is a clear interface with a difference in refractive index between the hard coat layer and the base material. Visibility, that is, glare and partial iris reflection occurs when viewed from a certain angle. In order to improve this phenomenon, studies have been made to improve the coating film thickness accuracy, increase the refractive index of the hard coat layer, and reduce the refractive index difference. (See Patent Document 7)
JP-A-55-15825 (Page 2, column 1, column 17-2, line 12) JP-A-58-78761 (page 3, column 2, lines 5-12) JP 60-248232 A (page 5, column 2, lines 6 to 20) JP-A-2-16050 (page 2, column 2, column 3, page 3, column 2, line 18) JP-A-62-263237 (page 1, column 1, lines 4 to 9) JP-A-3-229726 (first page, first column, fourth column, second column, first line) JP 2002-241527 (paragraphs [0007] to [0008])

  However, the conventional techniques described above have the following problems. First, the surface etching method and the surface activation method not only do not provide sufficient adhesion between the substrate multilayer sheet and the hard coat layer, but also have problems such as complicated processing steps and disposal of processing solutions. In addition, it is necessary to dramatically improve mechanical characteristics, particularly tear resistance, as a function of protecting the display and preventing glass scattering.

  In addition, when a polyester base film laminated with an acrylic resin or a urethane resin is used to provide adhesiveness, the laminated film is excellent in adhesion to the hard coat layer that is a coating, Adhesiveness with the material film tends to be insufficient. In particular, hard coat sheets have recently been used in various applications, such as harsh conditions that could not be imagined so far, such as high humidity and high ambient temperature (the present invention). In this case, the adhesiveness of the hard coat layer under such conditions is called “under wet heat”), and there are many cases where the function as a hard coat sheet cannot be satisfied. .

  In addition, when a polyester base material multilayer sheet laminated with a polyester resin is used, the laminated film has good adhesiveness with the polyester sheet base material, but is sufficient in adhesiveness with the hard coat layer. In many cases, the adhesiveness was not obtained, and of course, the adhesiveness with the hard coat layer under wet heat was insufficient as in the case of the acrylic resin and urethane resin.

  As a method for improving the adhesiveness under the above-described wet heat, generally, a method of crosslinking the resin and improving the adhesiveness can be considered. For example, an acrylic resin, a urethane resin, or a polyester resin may be added with a melamine crosslinking agent, an isocyanate crosslinking agent, an epoxy crosslinking agent, an oxazoline crosslinking agent, or the like. However, those satisfying the adhesiveness under normal conditions and the adhesiveness under wet heat have not been obtained.

  Furthermore, in the method of providing a primer layer that improves adhesion between the hard coat layer and the substrate multilayer sheet, the number of steps increases, and therefore, there is adhesion of foreign matter to the film surface between each step or during each step. Due to the occurrence of scratches on the film surface due to contact with a crossing roll or the like, there is a problem that the productivity is greatly reduced, and the processing cost is increased because two or more steps are required.

  In addition, as a method for improving the iris-like reflection that occurs when trying to improve the adhesion between the hard coat layer and the substrate by the method as described above, the coating thickness accuracy is improved or the refractive index of the hard coat layer is increased. However, there is a limit to the improvement of coating thickness accuracy, and if the refractive index of the hard coat layer is increased, sufficient hardness is not exhibited, and the surface reflectance increases and the transmission image is increased. There are problems such as difficulty in seeing.

  An object of the present invention is to solve the above-mentioned drawbacks in the prior art and to provide a hard coat multilayer sheet having excellent adhesion between the base multilayer sheet and the hard coat layer.

  In order to achieve such an object, the present inventors have conducted intensive research, and as a result, are a hard coat multilayer sheet comprising a substrate multilayer sheet (a) having a laminated structure and a hard coat layer (b), Hard coat when multilayer sheet (a) has at least two layers of a layer mainly composed of polyester (A) and a layer mainly composed of polyester (B), and is irradiated with light having a wavelength of 400 to 660 nm It has been found that a hard-coated multilayer sheet capable of achieving its purpose is obtained by the constitution as a hard-coated multilayer sheet, wherein the average waviness amplitude of the reflectance of the layer (b) is 1% or less. It came to be completed.

  According to the present invention, the hard coat layer is laminated on the base material multilayer sheet, and the average undulation amplitude of the reflectance on the hard coat layer side at a wavelength of 400 to 660 nm is 1% or less, so that the adhesive property is excellent and high. A hard coat multilayer sheet excellent in surface hardness and abrasion resistance, suppressed in iris pattern generation and excellent in visibility can be obtained. In addition, it is possible to provide a hard coat layer at the same time as film formation, which is excellent in productivity, extremely good adhesion between the hard coat layer and the substrate multilayer sheet, and further excellent in mechanical properties. A multilayer sheet is obtained.

  The hard coat multilayer sheet of the present invention is a hard coat multilayer sheet comprising a substrate multilayer sheet (a) having a laminated structure and a hard coat layer (b), wherein the substrate multilayer sheet (a) is a polyester (A). Average waviness of the reflectance of the hard coat layer (b) when it is irradiated with light having a wavelength of 400 to 660 nm. The hard coat multilayer sheet is characterized in that the amplitude is 1% or less.

  The base material multilayer sheet as the base material is a base material in which a layer mainly composed of polyester A and a layer mainly composed of polyester B are regularly laminated in the thickness direction, and at least those layers are two or more. A multilayer sheet, in which polyester A and polyester B are composed of at least three kinds of diol derivatives and dicarboxylic acid derivatives, polyester B contains 10 to 60 mol% of one component thereof (component X), and It is preferable that the polyester A contains 0.1 to 10 mol% of the component X. Here, the amount of each component is a ratio with respect to the whole dicarboxylic acid derivative or diol derivative of the same kind as the component X contained in each layer.

  Component X is preferably 1,4-cyclohexanedimethanol, bisphenol A ethylene oxide adduct, dimer acid, polyalkylene dicarboxylic acid, more preferably 1,4-cyclohexanedimethanol, bisphenol A ethylene oxide adduct. More preferably 1,4-cyclohexanedimethanol. In the case where the component X is such, the tear resistance and high transparency as the object of the present invention can be efficiently achieved at the same time. Since polyester B is rigid and excellent in impact absorption, it is possible to achieve improvement in tear resistance and impact resistance in order to suppress propagation of cracks transmitted by impact. Further, such polyester B is excellent in transparency and also hardly visible and whitening due to aging at room temperature.

  The polyester in the present invention includes a polyester resin that is a polycondensate of a dicarboxylic acid derivative and a diol derivative. For example, polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, polyethylene-2,6-naphthalate, poly 1,4-cyclohexane. Dimethylene terephthalate, 1,4-cyclohexanedimethanol copolymerized polyethylene terephthalate, or the like can be used. In particular, since polyethylene terephthalate is inexpensive, it can be used for a wide variety of applications and is highly effective. In addition, these resins may be homo resins, and may be copolymers or blends.

  Here, the polyester A of the present invention is preferably a crystalline polymer, and the polyester B is preferably an amorphous polymer. Moreover, it is preferable that the polyester which comprises each layer has the tensile elasticity modulus of 1400 Mpa or more. More preferably, it is 1550 MPa or more, More preferably, it is 1700 MPa or more. In general, when the tensile modulus of the thermoplastic resin is lower than 1400 MPa, it tends to be whitened over time even at room temperature, which is not preferable because haze increases.

  Examples of the dicarboxylic acid derivative of the present invention include terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalene acid, 1,5-naphthalene acid, 2,6-naphthalene acid, 4,4′-diphenyldicarboxylic acid, 4,4 Examples include '-diphenylsulfone dicarboxylic acid, sebacic acid, dimer acid, and the like, and those obtained by esterifying them. Examples of the diol derivative include 1,2-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentadiol, diethylene glycol, polyalkylene glycol, 1,4-cyclohexanedimethanol, and bisphenol A. Examples include ethylene oxide adducts.

  By adopting such a configuration, it is possible to provide a glass protective sheet or a display antireflection sheet having a high degree of optical function because whitening caused by a thermal history received during processing is suppressed while having high tear strength. It will be.

  Here, the layer containing the polyester of the present invention as a main component is a layer containing at least 70 wt% of the polyester. The polyester may be a homo-resin, copolymerized or blended. Also good. In each layer, various additives such as an antioxidant, an antistatic agent, a crystal nucleating agent, inorganic particles, organic particles, a thinning agent, a heat stabilizer, a lubricant, an infrared absorber, and an ultraviolet absorber are included. It may be added.

  The number of layers in the present invention is preferably 10 layers or more, more preferably 20 layers or more. When the number of layers is less than 10, it is not preferable because sufficient tear resistance cannot be obtained. In particular, according to various findings by the present inventors, the upper limit of the number of layers is not particularly limited, and may be, for example, about several hundred layers. It is good to have about 1000 layers. Therefore, according to the knowledge of the present inventors, the preferred number of layers is 10 to 1000 layers, more preferably 30 to 600 layers. More preferably, it is 31 to 128 layers.

  The substrate multilayer sheet constituting the hard coat multilayer sheet of the present invention has a structure in which at least a layer mainly composed of polyester A and a layer mainly composed of polyester B are regularly laminated in the thickness direction. It is preferable.

When the polyester A, the polyester B, and the polyester C are used, they are more preferably laminated in a regular permutation such as A (BCA) _n , A (BCBA) _n , A (BABCBA) _n . Here, n is the number of repeating units. For example, when n = 3 in A (BCA) _n , the layers are stacked in a permutation of ABCABCABCA in the thickness direction. Moreover, when it consists of two types of polyester, it is preferable to have the structure where they were laminated | stacked alternately.

  That is, in the present invention, “a structure in which at least a layer containing polyester A as a main component and a layer containing polyester B as a main component are regularly laminated in the thickness direction” means that polyester A in the laminated film is a main component. The order of the arrangement in the thickness direction of the layer comprising polyester B and the layer comprising polyester B as the main component is not in a random state, and the layers other than the layer comprising polyester A as the main component and the layer comprising polyester B as the main component. For the three or more layers, the order of arrangement is not particularly limited.

  As described above, the polyester A and the polyester B of the present invention are preferably composed of at least three kinds of diol derivatives and dicarboxylic acid derivatives. Moreover, in this invention, it is preferable that polyester B contains 10-60 mol% of those 1 components (component X), and polyester A contains 0.1-10 mol% or less of said components X. More preferably, the polyester B contains 20 to 40 mol% of the component X. Further, it is more preferable that the polyester A contains at least 0.2 to 5 mol% of X. When the layer containing polyester A as a main component contains less than 0.1 mol% of X, oligomer precipitation on the surface, which causes whitening at high temperatures, cannot be suppressed, and haze increases. If more than 10 mol% of X is added to the layer containing polyester A as a main component, the whitening suppression is effective, but the tear strength is greatly reduced.

  In this way, by adding a specific amount of the component X common to the polyester B to the layer containing the polyester A as a main component, precipitation of oligomers can be prevented and whitening at high temperatures can be greatly reduced. It is.

  In the base multilayer sheet of the present invention, the thickness of the layer mainly composed of polyester A is preferably 1 to 30 μm, and the thickness of the layer mainly composed of polyester B is preferably 0.1 to 5 μm. . More preferably, the thickness of the layer mainly composed of polyester A is 3 to 25 μm, and the thickness of the layer mainly composed of polyester B is 0.3 to 3 μm. By adopting such a configuration, not only high tear resistance can be obtained, but also precipitation of oligomers that cause whitening can be further suppressed.

  In the base material multilayer sheet of the present invention, the total light transmittance is preferably 88% or more and the haze is preferably 6% or less. More preferably, the total light transmittance is 89% or more and the haze is 3% or less. More preferably, the total light transmittance is 89% or more and the haze is 1% or less. This is because the display becomes unclear in the use of a glass protective sheet or a display antireflection sheet in which visibility is important.

  In the base material multilayer sheet of the present invention, an easy slip layer, an easy adhesion layer, an adhesive layer, an antireflection film, a hard coat layer, a near infrared shielding layer, an electromagnetic wave shielding layer, a conductive layer, an antifouling layer, a dew condensation preventing layer, etc. Or may be formed on the surface layer. These layers are not particularly limited, and various conventionally known techniques can be used. By having these layers, it is optimal as a glass protective sheet or display.

  Next, although the preferable manufacturing method of the base material multilayer sheet of this invention is demonstrated below, it is not limited to this manufacturing method.

  Polyester A and polyester B are prepared in the form of pellets. If necessary, the pellets are pre-dried in hot air or under vacuum and supplied to an extruder. In the extruder, the resin melted by heating to the melting point or higher is made uniform in the amount of resin extruded by a gear pump or the like, and foreign matter or modified resin is filtered through a filter or the like. Further, the resin is formed into a desired shape with a die and then discharged.

  As a method for obtaining a multilayer sheet, a method of laminating thermoplastic resins sent from different flow paths using two or more extruders in multiple layers using a multi-manifold die, a field block, a static mixer, etc. Can be used. Moreover, you may combine these arbitrarily.

  Sheets stacked in multiple layers discharged from a die are extruded onto a cooling body such as a casting drum, and cooled and solidified to obtain a casting sheet. At this time, it is preferable to use a wire-like, tape-like, needle-like, or knife-like electrode, which is brought into close contact with a cooling body such as a casting drum by electrostatic force and rapidly solidified.

  The casting sheet thus obtained may be biaxially stretched as necessary. Biaxial stretching refers to stretching in the longitudinal direction and the transverse direction. Stretching may be performed sequentially biaxially or simultaneously in two directions. Further, re-stretching may be performed in the longitudinal and / or transverse direction.

  Here, the stretching in the longitudinal direction refers to stretching for imparting molecular orientation in the longitudinal direction to the film, and is usually performed by a difference in peripheral speed between rolls. This stretching may be performed in one stage, or may be performed in multiple stages using a plurality of roll pairs. The draw ratio varies depending on the type of resin, but usually 2 to 15 times is preferable, and 2 to 7 times is particularly preferably used when polyethylene terephthalate is used.

  The uniaxially stretched film thus obtained is subjected to surface treatment such as corona treatment, flame treatment, and plasma treatment on the surface opposite to the hard coat surface as necessary, and then it is easy to slip and adhere easily. In addition, known functions such as antistatic properties can be imparted by in-line coating.

  Next, a hard coat layer is provided on the base multilayer sheet after uniaxial stretching. Details will be described below.

  In addition, the simultaneous biaxial stretching method, in which longitudinal stretching and lateral stretching are simultaneously performed on a non-stretched film using a stenter, shortens the process compared to the sequential biaxial stretching method, leading to cost reduction, and is less likely to cause stretching breaks and roll scratches. Therefore, it is particularly effective as the glass protective sheet for flat display of the present invention. When using the coaxial biaxial stretching method, it is preferable to provide a hard coat layer on the unstretched sheet.

In the present invention, for example, when the sequential biaxial stretching method is used, the stretching condition in the longitudinal direction varies depending on the thermoplastic resin to be used, but usually 2 to 15 times is preferable. The range of 5 to 10 times, more preferably 3 to 5 times is preferable. The stretching temperature is preferably 1000 to 50000% / min, and the stretching temperature is preferably in the range of the glass transition temperature Tg or more (glass transition temperature + 50 ° C.) of the thermoplastic resin having the highest composition ratio, and is stretched in the longitudinal direction. By doing so, a uniaxially oriented film is obtained.

  Next, the stretching in the width direction is performed using a conventionally used tenter, and the stretching temperature is preferably not less than the glass transition temperature Tg of the thermoplastic resin having the highest component ratio, and not more than (glass transition temperature Tg + 80 ° C.). May be in the range of not less than the glass transition temperature Tg of the thermoplastic resin and not more than (glass transition temperature Tg + 60 ° C.), and the stretching ratio may be 2 to 10 times, more preferably 2.5 to 5 times. The stretching speed at that time is not particularly limited, but is preferably 1000 to 50000% / min. Moreover, when extending | stretching by the simultaneous biaxial stretching method, the method of simultaneous biaxial stretching using the tenter by the drive system using a linear motor is preferable. The simultaneous biaxial stretching temperature is preferably not less than the glass transition temperature Tg of the thermoplastic resin and not more than (glass transition temperature Tg + 50 ° C.). If the stretching temperature deviates greatly from this range, uniform stretching cannot be performed, resulting in uneven thickness and tearing of the film. The draw ratio may be 2 to 10 times in the longitudinal direction and the transverse direction, respectively. Although it does not specifically limit as extending | stretching speed | rate, 2000-50000% / min is preferable. Next, heat treatment is performed as necessary in order to reduce the thermal contraction rate and to provide flatness. In order to obtain the low haze as described above, which is the effect of the present invention, and the elongation at break of at least one of the longitudinal direction and the width direction is in the range of 100 to 300%, and the breaking stress at that time is 120 to 400 MPa. In order to obtain a high impact resistance within the range, the heat treatment conditions are either constant length, fine stretch, or relaxed state (the glass transition temperature Tg of the thermoplastic resin having the highest component ratio). It is preferable to carry out for 0.5 to 60 seconds within the range of (the glass transition point of the thermoplastic resin having the highest constituent ratio + 100 ° C.), and (the glass transition temperature Tg of the thermoplastic resin having the highest constituent ratio + 40 ° C.) It is most preferable to carry out for 0.5 to 10 seconds in the range of (the glass transition point of the thermoplastic resin having the highest composition ratio + 80 ° C.). Below the above range, the thermal shrinkage rate becomes large, and above the above range, the haze is high and the impact resistance is lowered.

  In particular, the glass protective sheet for a flat display according to the present invention having a total light transmittance of preferably 88% or more, more preferably 89% or more can be obtained by having an antireflection film on one surface layer of the film. The antireflection film is not particularly limited, and a conventionally known technique or the like can be used.

  Thus, the film biaxially oriented and heat-treated by each method is gradually cooled to room temperature and wound with a winder. The cooling method is preferably gradually cooled to room temperature in two or more stages. At this time, performing a relaxation treatment of about 0.5 to 10% in the longitudinal direction and the width direction is effective in reducing the thermal dimensional stability. As the cooling temperature, the first stage is (heat treatment temperature −20 ° C.) to (heat treatment temperature −80 ° C.), and the second stage is (first stage cooling temperature −30 ° C.) to (first stage cooling temperature −40 ° C.). A range is preferred, but not limited thereto. In the above-described method, in particular, in order to produce a hard coat multilayer sheet having an impact strength of 8 to 40 J, a heat treatment having a multilayer structure composed of at least two kinds of thermoplastic resins having a glass transition temperature of 40 ° C. or less. In the range of (Glass transition temperature Tg of the thermoplastic resin with the highest composition ratio) (Glass transition temperature of the thermoplastic resin with the highest composition ratio + 100 ° C.) for 0.5 to 60 seconds. In order to produce a glass protective film having an impact strength of 10 to 40 J, heat treatment (glass transition temperature Tg of the thermoplastic resin with the highest composition ratio Tg + 40 ° C.) / (Glass transition point of the thermoplastic resin with the highest composition ratio + 80 It is important to carry out for 0.5 to 10 seconds in the range of ° C.

  In order to realize such a substrate multilayer sheet, the amount of particles inside the sheet is set to 0.04 wt% or less, and a low refractive index layer is provided on at least one side in order to suppress reflection on the film surface. can do.

  After being heat-treated in this way, it is gradually cooled down uniformly, then cooled to room temperature and wound up. Moreover, you may use a relaxation process etc. together in the case of annealing from heat processing as needed.

  After applying a surface treatment such as corona treatment, flame treatment, or plasma treatment to the surface opposite to the hard coat surface as necessary, the uniaxially stretched sheet or unstretched sheet obtained by the above method, and then into an aqueous emulsion Antifoaming agents, thickeners, antistatic agents, inorganic particles, organic particles, organic lubricants, polymer compounds, UV absorbers, light stabilizers, dyes, pigments or stabilizers can be used. These can improve the properties of the surface of the base multilayer sheet depending on the application. The wet thickness immediately after the water-based coating is 5 to 15 μm, but most of the water evaporates during stretching, and the thickness of the functional film remaining on the surface is 80 to 500 nm. By utilizing these known techniques, known functions such as slipperiness, easy adhesion, and antistatic properties can be imparted by in-line coating.

  In the hard coat multilayer sheet of the present invention, a hard coat layer is laminated on at least one surface of the substrate multilayer sheet. This hard coat layer is composed of an acrylic resin, a urethane resin, a melamine resin, an organic silicate compound, a silicone. It can be composed of a resin or a metal oxide. In particular, silicone resins and acrylic resins are preferable in terms of hardness and durability, and acrylic resins, particularly active ray curable acrylic resins, in terms of curability, flexibility, and productivity. Or what consists of thermosetting acrylic resin is preferable.

  The actinic ray curable acrylic resin and the thermosetting acrylic resin are those containing a polyfunctional acrylate, an acrylic oligomer or a reactive diluent as a polymerization curing component, and in addition, if necessary, a photoinitiator, You may use what contains a photosensitizer, a thermal-polymerization initiator, or a modifier.

  Acrylic oligomers include polyester acrylates, urethane acrylates, epoxy acrylates and polyether acrylates, including those in which a reactive acrylic group is bonded to an acrylic resin skeleton, and rigid materials such as melamine and isocyanuric acid. In this invention, particularly when urethane acrylate is used, the adhesion to the base film can be remarkably improved.

  In addition, the reactive diluent serves as a solvent for the coating process as a coating medium, and has a group that itself reacts with a monofunctional or polyfunctional acrylic oligomer. It becomes a polymerization component.

  Specific examples of these acrylic oligomers, reactive diluents, photopolymerization initiators, photosensitizers, thermal polymerization initiators, crosslinking devices and the like are Shinzo Yamashita, Tosuke Kaneko, “Crosslinking Agent Handbook”, Taiseisha 1981. The yearly publication, pages 267 to 275 and pages 562 to 593 can be referred to, but the present invention is not limited to these.

  Commercially available polyfunctional acrylic cured paints include Mitsubishi Rayon Co., Ltd. (trade name “Diabeam” series, etc.), Nagase Sangyo Co., Ltd. (trade name “Denacol” series, etc.), Shin-Nakamura Co., Ltd .; (Product name “NK Ester” series, etc.), Dainippon Ink and Chemicals Co., Ltd .; (Product name “UNIDIC” series, etc.), Toa Gosei Chemical Industries Co., Ltd. (product name “Aronix” series, etc.), Nippon Oil & Fats Co., Ltd. (Trade name “Blemmer” series, etc.), Nippon Kayaku Co., Ltd .; (trade name “KAYARAD” series, etc.), Kyoeisha Chemical Co., Ltd .; (trade names “light ester” series, “light acrylate” series, etc.) The product can be used.

  In the present invention, as a modifier for the hard coat layer, a coating property improver, an antifoaming agent, a thickener, an antistatic agent, inorganic particles, organic particles, an organic lubricant, an organic polymer compound, an ultraviolet ray, Absorbers, light stabilizers, dyes, pigments or stabilizers can be used, and these are used as a composition component of the coating layer constituting the hard coat layer within a range that does not impair the reaction due to active rays or heat, The properties of the hard coat layer can be improved depending on the application. In addition, in this specification, the weight% display of a hard-coat layer formation composition component shall be computed based on the reaction result in the hard-coat layer completed after completion | finish of hardening reaction etc. in principle. That is, if it is a monomer, it is counted as a residue in the polymer in the reaction product. Therefore, a solvent that evaporates after completion of the reaction is not counted as a hard coat layer forming composition even if it is contained as a coating solution.

  When the typical thing of the acrylic compound which comprises a hard-coat layer is illustrated, the monomer which has 3 (more preferably 4, more preferably 5) or more (meth) acryloyloxy groups in 1 molecule (In addition, If it is too much, the monomer will be highly viscous and difficult to handle, and it will have to be of high molecular weight, making it difficult to use as a coating solution, so (meth) acryloyloxy in one molecule The number of groups is preferably 10 or less.)) And a mixture of at least one monomer having 1 to 2 ethylenically unsaturated double bonds in one molecule. And a hard coat layer obtained by actinic ray curing or heat curing is preferably used because it is excellent in hardness, wear resistance and flexibility.

  Three or more (meth) acryloyloxy groups in one molecule (in the present specification, "... (meth) acryl ..." means "... acrylic ... or ... .. ”is abbreviated as“. ”As a monomer having 3 or more (meth) acrylic hydroxyl groups of a polyhydric alcohol having 3 or more alcoholic hydroxyl groups in one molecule. The compound etc. which are the esterified products of an acid can be mentioned.

  Specific examples include pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, Dipentaerythritol hexa (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol triacrylate hexamethylene diisocyanate urethane prepolymer, pentaerythritol triacrylate toluene diisocyanate urethane prepolymer, pentaerythritol triacrylate isophorone diisocyanate urethane prepolymer, etc. Can be used. These monomers can be used alone or in combination of two or more.

  The proportion of the monomer having three or more (meth) acryloyloxy groups in one molecule is preferably 20 to 90% by weight, more preferably 30 to 80% by weight based on the total amount of the hard coat layer constituent components. %, Most preferably 30 to 70% by weight.

  When the proportion of the monomer used is less than 20% by weight, it may be insufficient in terms of obtaining a cured film having sufficient abrasion resistance, and when the amount exceeds 90% by weight. In some cases, the shrinkage due to curing is large, strain remains in the cured film, the flexibility of the film is lowered, or the curled side is greatly curled.

  Next, the monomer having 1 to 2 ethylenically unsaturated double bonds in one molecule can be used without particular limitation as long as it is a normal monomer having radical polymerizability.

  Moreover, as a compound which has two ethylenically unsaturated double bonds in a molecule | numerator, the following (a)-(f) (meth) acrylate etc. can be used.

That is,
(A) C2-C12 alkylene glycol (meth) acrylic acid diesters: ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, neopentyl Glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, and the like.

  (B) (Meth) acrylate diesters of polyoxyalkylene glycol: diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, Polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, etc.

  (C) Polyhydric alcohol (meth) acrylic acid diesters: pentaerythritol di (meth) acrylate and the like.

  (D) (Meth) acrylic acid diesters of ethylene oxide and propylene oxide adducts of bisphenol A or bisphenol A hydride: 2,2′-bis (4-acryloxyethoxyphenyl) propane, 2,2′-bis ( 4-acryloxypropoxyphenyl) propane and the like.

  (E) Two or more in a molecule obtained by reacting a terminal isocyanate group-containing compound obtained by reacting a diisocyanate compound and two or more alcoholic hydroxyl group-containing compounds in advance with an alcoholic hydroxyl group-containing (meth) acrylate. Urethane (meth) acrylates having a (meth) acryloyloxy group.

and,
(F) Epoxy (meth) acrylates having two or more (meth) acryloyloxy groups in the molecule obtained by reacting a compound having two or more epoxy groups in the molecule with acrylic acid or methacrylic acid.
As the compound having one ethylenically unsaturated double bond in the molecule, methyl (meth) acrylate, ethyl (meth) acrylate, n- and i-propyl (meth) acrylate, n- , Sec-, and t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, hydroxyethyl ( (Meth) acrylate, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, glycidyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, N-hydroxyethyl (meth) acrylamide, N Vinylpyrrolidone, N- vinyl-3-methylpyrrolidone, or the like can be used N- vinyl-5-methyl pyrrolidone. These monomers may be used alone or in combination of two or more.

  The use ratio of the monomer having 1 to 2 ethylenically unsaturated double bonds in one molecule is preferably 10 to 50% by weight, more preferably 20 to 20% by weight based on the total amount of the constituent components of the hard coat layer. 40% by weight. When the proportion of the monomer used exceeds 50% by weight, it may be difficult to obtain a cured film having sufficient wear resistance.

  Moreover, when the use ratio is less than 10% by weight, the flexibility of the coating film may be lowered, or the adhesiveness with the laminated film provided on the base film may be lowered.

  In the present invention, as a method of curing the above hard coat composition, for example, a method of irradiating ultraviolet rays as active rays, a high temperature heating method, or the like can be used. It is desirable to add a photopolymerization initiator or a thermal polymerization initiator to the composition.

  Specific examples of the photopolymerization initiator include acetophenone, 2,2-diethoxyacetophenone, p-dimethylacetophenone, p-dimethylaminopropiophenone, benzophenone, 2-chlorobenzophenone, 4,4′-dichlorobenzophenone, 4,4′-bisdiethylaminobenzophenone, Michler's ketone, benzyl, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, methylbenzoyl formate, p-isopropyl-α-hydroxyisobutylphenone, α-hydroxyisobutylphenone, 2, Carbonyl compounds such as 2-dimethoxy-2-phenylacetophenone and 1-hydroxycyclohexyl phenyl ketone, tetramethylthiuram monosulfide, tetramethylthio Sulfur compounds such as uranium disulfide, thioxanthone, 2-chlorothioxanthone, and 2-methylthioxanthone can be used. These photopolymerization initiators may be used alone or in combination of two or more. Moreover, as a thermal polymerization initiator, a peroxide compound such as benzoyl peroxide or di-t-butyl peroxide can be used.

  The amount of the photopolymerization initiator or thermal polymerization initiator used is suitably 0.01 to 10 parts by weight with respect to 100 parts by weight of the hard coat layer forming composition. When an electron beam or gamma ray is used as a curing means, it is not always necessary to add a polymerization initiator.

  The hard coat layer forming composition used in the present invention has a thermal polymerization prevention such as hydroquinone, hydroquinone monomethyl ether or 2,5-t-butyl hydroquinone in order to prevent thermal polymerization during production and dark reaction during storage. It is desirable to add an agent. The addition amount of the thermal polymerization inhibitor is preferably 0.005 to 0.05% by weight with respect to the total weight of the hard coat layer forming composition.

The hard coat layer in the invention preferably contains a polyisocyanate compound and / or a derivative thereof. The polyisocyanate compound in the hard coat layer assists the function of directly bonding the hard coat layer and the base film without a primer layer. For example, as the polyisocyanate compound, 2,4- and / or 2,6 -Tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate (MDI), polymeric MDI, 1,5-naphthylene diisocyanate, tolidine diisocyanate, 1,6-hexamethylene diisocyanate (HDI), trimethylhexamethylene diisocyanate, isophorone diisocyanate, xylylene At least such as diisocyanate (XDI), hydrogenated XDI, hydrogenated MDI, lysine diisocyanate, triphenylmethane triisocyanate, tris (isocyanatephenyl) thiophosphate, etc. The thing more than a dimer is mentioned. These polyisocyanate compounds can be used alone or in admixture of two or more. These polyisocyanate compounds and / or derivatives thereof are mixed with the hard coat layer forming composition and applied to the base multilayer sheet. Is done. The blending amount of the polyisocyanate compound and / or derivative thereof is preferably 0.5 to 50 parts by weight with respect to 100 parts by weight of the composition forming the hard coat layer in terms of adhesiveness, surface hardness and heat-and-moisture resistance. More preferably, it is 1-30 weight part, More preferably, it is 3-20 weight part. When the blending amount is less than 0.5 parts by weight, the effect of improving the adhesiveness may be insufficient, and when the blending amount exceeds 50 parts by weight, the surface hardness may be lowered.

The coating composition containing the active ray curable or thermosetting composition for forming the hard coat layer used in the present invention has improved workability during coating, control of the coating film thickness, and base material multilayer sheet. For the purpose of forming a mixed layer, an organic solvent may be blended, but it is preferably as small as possible in terms of reduction in film formation speed due to drying and explosion-proof property in the drying furnace due to solvent evaporation. The organic solvent to be used is preferably a solvent having a solubility parameter that is as close as possible to the solubility parameter of the thermoplastic resin to be used (difference in solubility parameter is preferably within ± 1.0, more preferably within ± 0.8). .
For example, if the thermoplastic resin is polyethylene terephthalate (solubility parameter 10.7), N-methyl-2-pyrrolidone (solubility parameter 11.3) is preferred.

The solubility parameter described in the present invention is a value calculated by the Fedors method (the calculation method is shown in, for example, Properties of Polymers, chapter 7 (DW Van Kreveren, 1976, Elsevier)). Depending on the structure, parameters of chemical species to be contained are not required, and some of them cannot be calculated by the method of Fedors. In that case, substitution was made by using an approximate chemical species (for example, about —SO ₂ —). There are no parameters, but the values of -S-, -O-, and -O- are used instead).

  In the present invention, the average waviness amplitude of the reflectance on the hard coat layer side at a wavelength of 400 to 660 nm should be 1% or less. Preferably it is 0.8% or less, More preferably, it is 0.5% or less. Here, the reflectance indicates a ratio with respect to incident light reflected by a slight interface between the hard coat layer and the substrate, and the surface reflectance indicates a ratio with respect to incident light reflected by the surface of the hard coat layer.

  When the average waviness amplitude of the reflectance on the hard coat layer side is larger than 1%, an iris pattern is generated when light having a wavelength intensity distribution such as a fluorescent lamp is reflected, and visibility is deteriorated. Further, the adhesiveness between the hard coat layer and the substrate is lowered.

  The average waviness amplitude of the reflectance at a wavelength of 400 to 660 nm described in the present invention means that the surface opposite to the measurement surface (hard coat layer surface side) is roughened so that the 60 ° C. gloss (JIS Z 8741) is 10 or less. In the reflectance observed when the reflectance is measured when the reflectance at an incident angle of 10 degrees is measured with a spectrophotometer on the measurement surface, waviness at a wavelength of 400 to 660 nm (the reflectance changes with the change in wavelength) The difference between the maximal value (first derivative = 0, second derivative <0) and the minimum value (first derivative = 0, second derivative> 0) in the calculus meaning Mean value of That is, as shown in FIG. 3, the line (peak line) connecting the peaks (maximum points) of the undulations of the reflectance at wavelengths of 400 to 660 nm and the line (valley line) connecting the valley bottoms (minimum points) of the undulations. The difference between the two line graphs of reflectivity is 13 sample points at 20 nm intervals including the boundary points (400, 660 nm) (locations where the wavelength is (400 + 20 × i (i = integer of 0 to 13)) nm) It is the average of the values obtained in (1).

  The surface reflectance of the hard coat multilayer sheet of the present invention is preferably 6% or less. More preferably, it is 5.5% or less. The lower the surface reflectance, the better.

  This is because when the surface reflectance is larger than 6%, sunlight or fluorescent lamps are reflected when used for a display, a nameplate, a touch panel, etc., the visibility is lowered and an unpleasant impression is given.

The haze of the hard coat multilayer sheet of the present invention is preferably 3% or less as described above for the base multilayer sheet, and preferably 6% or less for the hard coat multilayer sheet.
More preferably, it is 3% or less as the hard coat multilayer sheet, most preferably 1% or less as the hard coat multilayer sheet, and the ratio of the haze of the base multilayer sheet to the haze of the hard coat multilayer sheet is not particularly limited.

  This is because when the haze is larger than 6%, the transmission image becomes unclear when used for glass, a display, a nameplate, a touch panel and the like.

  In the hard coat layer described in the present invention, various additives can be further blended as necessary within a range where the effects of the present invention are not impaired. For example, stabilizers such as antioxidants, light stabilizers, ultraviolet absorbers, surfactants, leveling agents, antistatic agents, and the like can be used.

  As a coating means (coating liquid) containing a composition for forming a hard coat layer, various coating methods such as reverse coating method, gravure coating method, rod coating method, bar coating method, die coating method are used. Alternatively, a spray coating method or the like can be used.

  Examples of the actinic rays used in the present invention include electromagnetic waves that polymerize acrylic vinyl groups such as ultraviolet rays, electron beams, and radiation (α rays, β rays, γ rays, etc.). It is preferable. As the ultraviolet ray source, an ultraviolet fluorescent lamp, a low pressure mercury lamp, a high pressure mercury lamp, an ultra high pressure mercury lamp, a xenon lamp, a carbon arc lamp, or the like can be used. Moreover, when irradiating actinic radiation, if it irradiates under a low oxygen concentration, it can harden | cure efficiently. Furthermore, the electron beam system is advantageous in that the apparatus is expensive and needs to be operated under an inert gas, but it is not necessary to include a photopolymerization initiator or a photosensitizer in the coating layer. is there.

  As the heat necessary for the thermosetting used in the present invention, steam heater, electric heater, infrared heater or far-infrared heater is used. The heat given by spraying on the base material and the coating film using is used. Among them, heat by air heated to 200 ° C. or higher is preferable, more preferably heat by nitrogen heated to 200 ° C. or higher. It is preferable that the curing rate is high.

  Although what is necessary is just to determine the thickness of a hard-coat layer according to a use, 0.1-30 micrometers is preferable normally, More preferably, it is 1-15 micrometers. When the thickness of the hard coat layer is less than 0.1 μm, even if it is sufficiently cured, the surface hardness is not sufficient because it is too thin, and the surface tends to be damaged. On the other hand, when the thickness exceeds 30 μm Tends to crack in the cured film due to stress such as bending.

  Moreover, you may provide printing layers, such as a pattern, in the outermost layer of a hard-coat layer in the range which does not impair the effect of this invention.

  Further, the obtained hard coat multilayer sheet can be used by being bonded to various functional films by various methods.

  For example, the hard coat multilayer sheet of the present invention is bonded to a counterpart material using various adhesives on the opposite side of the hard coat layer, and the hard coat such as wear resistance and scratch resistance is attached to the counterpart material. It can also be used with a layer function. The adhesive used at this time is not particularly limited as long as it is an adhesive that adheres two objects by its adhesive action, and an adhesive made of rubber, acrylic, silicone or polyvinyl ether is used. it can.

Furthermore, the pressure-sensitive adhesive is roughly classified into two types, a solvent-type pressure-sensitive adhesive and a solventless pressure-sensitive adhesive. Solvent-type pressure-sensitive adhesives excellent in drying properties, productivity, and processability are still mainstream, but in recent years, they are changing to solvent-free pressure-sensitive adhesives in terms of pollution, energy saving, resource saving, safety, and the like. Among them, it is preferable to use an actinic radiation curable pressure-sensitive adhesive that is a pressure-sensitive adhesive that is cured in seconds by irradiation with actinic radiation and has excellent properties such as flexibility, adhesion, and chemical resistance. Specific examples of the curable acrylic pressure-sensitive adhesive can be referred to, edited by Japan Adhesive Society, “Adhesive Data Book”, published by Nikkan Kogyo Shimbun, 1990, pages 83 to 88, but are not limited thereto. Is not to be done. Commercially available multifunctional acrylic UV curable paints, such as Hitachi Chemical Polymer Co., Ltd. (trade name “XY” series, etc.), Toho Kasei Kogyo Co., Ltd. (trade name “Hi-Rock” series, etc.), Three Bond Co., Ltd. ( Product names such as “Three Bond” series), Toa Gosei Chemical Industry Co., Ltd .; (Product name “Arontite” series, etc.), Cemedine Co., Ltd .; (Product name “Cemeloc Super” series, etc.) can be used. However, it is not limited to these.

  When this type of pressure-sensitive adhesive is applied to a normal biaxially stretched polyester film, the adhesiveness becomes insufficient, and various primer treatments, for example, a laminated film made of an acrylic resin, a polyester resin, a urethane resin, etc. are provided. Thereby, the adhesiveness of a polyester film and an adhesive layer can be improved.

  In the present invention, a hard coat layer can be formed on one side, and a primer layer for improving the adhesiveness with these pressure-sensitive adhesive layers can be formed on the opposite side. It goes without saying that when the coating solution containing the actinic radiation curable or thermosetting composition to be formed is applied, it may be applied to the back side of the coating solution at the same time, dried and optionally stretched.

  As a method for obtaining the hard coat multilayer sheet of the present invention, a coating material containing a hard coat composition is applied to at least one surface of a thermoplastic film that is uniaxially stretched and crystal orientation is incomplete, A production method in which the film is stretched in a direction perpendicular to the uniaxial stretching direction through a preheating step, heat-fixed, and further subjected to active ray irradiation treatment as necessary.

  The present inventors have prepared the composition and the solubility parameter of the base thermoplastic resin and the solubility parameter of the coating composition including the base thermoplastic resin and the hard coat composition in more detail. By applying a composition having a difference of ± 1.0 or less, more preferably ± 0.8 or less, the hard coat composition penetrates into the surface of the substrate multilayer sheet before the completion of crystal orientation. It is estimated that the average undulation amplitude in the reflectivity of the resulting hard coat multilayer sheet can be reduced by obscuring the interface between the layer and the substrate film. In addition, this manufacturing method has advantages in terms of interfacial adhesion, prevention of dust adhesion, and cost by providing a hard coat layer at the same time as manufacturing a film.

It is preferable that the glass transition temperature of the thermoplastic resin which comprises the base material of the hard coat multilayer sheet of this invention is 50 degreeC or more, respectively. When the glass transition temperature of the thermoplastic resin is lower than 50 ° C., there is a possibility of causing dimensional change, discoloration, or whitening due to sunlight or heat generated from the display when used as a display.
The upper limit of the glass transition temperature is not particularly limited, but is 25 in the case of a crystalline thermoplastic resin.
The temperature is preferably 0 ° C. or lower, and more preferably 220 ° C. or lower. If it exceeds 250 ° C., it may be difficult to form the film, so care must be taken.

  In the present invention, layers mainly composed of polyethylene terephthalate and layers composed mainly of a copolymer polyester mainly composed of ethylene terephthalate and 1,4-cyclohexanedimethanol are laminated alternately in the thickness direction. More preferably. In the case of such a configuration, the impact resistance and high transparency which are the objects of the present invention can be achieved efficiently and simultaneously.

  The hard coat multilayer sheet of the present invention needs to have an impact strength in the range of 8 to 40J. More preferably, it is the range of 10-40J. The impact strength refers to impact absorption energy measured using a pendulum impact tester. If it is less than the said range, the intensity | strength as a glass protective sheet will run short, and it cannot prevent effectively the damage of glass, and the scattering of the glass piece after a damage. Moreover, when larger than the said range, it is unpreferable from a viewpoint of handleability.

  The hard coat multilayer sheet of the present invention preferably has a breaking elongation of 100 to 300% in at least one of the longitudinal direction and the width direction. More preferably, it is 130 to 250% of range. Further, the breaking stress at that time is preferably in the range of 120 to 400 MPa, and more preferably in the range of 150 to 250 MPa. If the elongation at break and the stress at break are less than the above ranges, the explosion-proof performance as a glass protective sheet is insufficient, and it is not possible to effectively prevent breakage of glass and scattering of glass pieces after breakage. In addition, the above range is not preferable from the viewpoint of handleability.

  The hard coat multilayer sheet of the present invention can be suitably used by being attached to the front surface of a glass for a flat panel display as one aspect of its use. The reason for this is that the hard-coated multilayer sheet of the present invention has a high surface hardness and satisfactory wear resistance, so that the surface is damaged by contact with other hard substances, friction or scratches, etc. It is difficult, and damages that occur on the surface do not significantly reduce the commercial value or become unusable in a short period of time. Furthermore, dimensional stability, heat resistance, transparency, electrical insulation, etc. are maintained, and further improvement in mechanical properties is satisfied. The flat panel display is, for example, a flat CRT display, a liquid crystal display, a plasma display, an organic EL display, a field emission display or the like, and is preferably used because it has a function as an antireflection sheet. As a method for imparting a function as an antireflection sheet, a known technique can be used. Usually, a high refractive layer is provided on the upper surface of the hard coat layer of the hard coat multilayer sheet, and a low refractive layer is further provided on the upper surface. Can be achieved by things.

  About glass, it is used for various uses from the outstanding light transmittance, gas barrier property, dimensional stability, etc. Higher performance glass is provided for buildings, automobiles, and flat panel displays.

  However, a drawback of glass is that it is easily broken or glass is scattered by breakage. This problem has been prominent in the field of flat panel displays. The flat display has a problem that the display glass itself tends to be thin due to demands for thinning and weight reduction, and accordingly, there is a problem that the flat display is easily broken during use. The hard coat multilayer sheet of the present invention has a high surface hardness on the surface of the sheet and also satisfies the wear resistance against the problem of glass breakage and glass scattering caused by breakage. It is difficult to damage the glass surface due to contact with a hard substance, friction or scratching, and the problem of breakage and scattering can be reduced. Furthermore, dimensional stability, heat resistance, transparency, electrical insulation, etc. are maintained, and further improvements in mechanical properties are satisfied. As a use mode, it is applied to at least one side of window glass for building materials and vehicles. It is used suitably. Moreover, if there exists a glass protection use which can make use of the characteristic of the glass protective film of this invention besides these uses, it can be used also for the use. The application range is not limited to these.

[Characteristic measurement method and effect evaluation method]
The characteristic measurement method and effect evaluation method in the present invention are as follows.

(1) Adhesion under normal conditions Under normal conditions (23 ° C., relative humidity 65%), 100 pieces of 1 mm ² crosscuts are put on the hard coat layer of the hard coat film, and cellophane tape manufactured by Nichiban Co., Ltd. is pasted thereon. And then reciprocating three times with a load of 19.6 N using a rubber roller, and after pressing, peeled off in the direction of 90 degrees, and evaluated in four stages according to the number of remaining hard coat layer layers (◎: 100, ○: 80-99) , Δ: 50-79, x: 0-49). (◎) and (○) were considered to have good adhesion.

(2) Adhesive property under wet heat The hard coat film was left for 48 hours under wet heat (80 ° C., relative humidity 85%). After the treatment, it was immediately taken out and allowed to stand for 5 minutes under normal conditions (23 ° C., relative humidity 65%), and then the same evaluation as (1) normal condition adhesiveness was performed.

(3) Abrasion resistance The load on the hard coat layer surface was changed with steel wool # 0000, and rubbed 10 times (speed: 10 cm / s) under a constant load at each load, resulting in scratch resistance (not scratched). The maximum load that was present was measured. 2 kg / cm ² is a level that is not a problem in practical use, and was regarded as acceptable.

(4) Pencil hardness Measured according to JIS K-5400 using HEIDON (manufactured by Shinto Kagaku Co., Ltd.). 2H or higher was accepted.

(5) Surface reflectivity and average waviness amplitude measurement The reflectivity at an incident angle of 10 degrees was measured using a U-3410 type spectrophotometer equipped with a 60 mmφ integrating sphere manufactured by Hitachi.

  The measurement sample was colored with black magic ink after roughening the back surface of the measurement surface (hard coat layer surface side) with No. 240 sandpaper in order to eliminate the influence of back surface reflection. The determination of the presence or absence of the influence of the back surface reflection was judged to have no influence of the back surface reflection if the glossiness of the back surface after the treatment (incident angle 60 °, light receiving angle 60 °) was 10 or less. The glossiness was measured in accordance with JIS Z 8741 using a digital variable glossiness meter UGV-5B (manufactured by Suga Test Instruments Co., Ltd.).

  The reflectance at a wavelength of 400 to 660 nm is measured, and a line connecting the peak part of the undulation (peak line) and a line connecting the valley bottom part of the swell (valley line) are measured at each sample point (11 points, A difference (mountain line-valley line) at a wavelength of (400 + 20 × i (i = integer of 0 to 13)) nm was determined, and the average was taken as the average undulation amplitude.

  Further, the average value of the peak line and the valley line at a wavelength of 550 nm was defined as the surface reflectance.

  The surface reflectance was 6% or less.

  An average swell amplitude of 1% or less was accepted.

(6) Total light transmittance and haze It measured using the direct reading type haze meter HGM-2DP (for C light sources) (Suga Test Instruments Ltd.). The haze (%) was calculated by dividing the diffuse transmittance by the total light transmittance and multiplying by 100. The number of n was 5 and the average value was adopted. The haze was 6% or less.

(7) Presence / absence of iris pattern After the surface of the measurement surface (hard coat layer surface) is roughened with 240 sandpaper in the same way as the measurement of surface reflectance and average waviness amplitude to eliminate the effect of back surface reflection. The sample prepared by coloring with black magic ink is placed in a dark room 30 cm directly under a three-wavelength fluorescent lamp (National Parrook, three-wavelength daylight white (FL 15EX-N 15W)). Evaluation was made based on whether or not the iris pattern was visible when visually observed.

Iris pattern clearly visible: Yes Iris pattern not visible: None Passed.

(8) Visibility A photograph was placed under the hard coat film, and it was examined whether or not the image when the photograph was seen through the hard coat film was clearly visible.

The image looks clear: ◎
The image is slightly blurred: ○
The image is blurred and difficult to see:
I can't see the image: ×
(9) Tear Strength Tear strength (gf) was measured based on JIS K 7128-2 (Elemendorf tear method) using a heavy load tear tester (manufactured by Toyo Seiki). The measured value was multiplied by 9.8 and divided by the measured film thickness to obtain the tear strength mN / μm.

  The tear strength was obtained by averaging the test results of 20 samples in the vertical direction and the horizontal direction. In addition, when not tearing substantially, it calculated as 3200 gf as an overrange. In addition, the measured value was displayed in the form of the measured value (MD) in the machine longitudinal direction / measured value (TD) in the width direction.

(10) Tensile modulus (Young's modulus)
The Young's modulus of the thermoplastic resin constituting each layer is determined according to ASTM test method D882-88. As the sample film, an unstretched film obtained by rapidly cooling and solidifying on a casting drum controlled to a temperature of 25 ° C. and improving the adhesion between the drum and the film using an electrostatic application device was used. The measurement was performed using an Instron type tensile tester (Orientec Co., Ltd. film tensile strength automatic measuring device “Tensilon AMF / RTA-100”). The Young's modulus was obtained by pulling under the conditions of a gap of 100 mm and a pulling speed of 200 mm / min.

(11) Intrinsic viscosity Measured at 25 ° C using orthochlorophenol as a solvent. In addition, n number was made into 3 times and the average value was employ | adopted.

(12) Layer configuration and layer thickness The layer configuration of the film was determined by electron microscope observation of a sample obtained by cutting a cross section of the film using a microtome. That is, using a transmission electron microscope HU-12 type (manufactured by Hitachi, Ltd.), the cross section of the film was enlarged and observed at 3000 to 200000 times, a cross-sectional photograph was taken, and the layer configuration and each layer thickness were measured.

(13) Crystallinity In order to evaluate the crystallinity in the thickness direction of each layer, the half-width of the Raman band near 1730 cm ^−1, which is a peak derived from carbonyl stretching vibration, was determined by laser Raman spectroscopy. The full width at half maximum was the average value of three points measured from the surface layer of each layer in the thickness direction.
<measuring device>
Ramoror T-64000 made by Jobin Yvon
Microprobe: 100 times objective lens Light source: Ar ⁺ laser (laser irradiation part is 1 μm in diameter)
Diffraction grating: 1800 gr / mm
Excitation wavelength: 514.5 nm
Detector: CCD (manufactured by Jobin Yvon)
<Measurement condition>
Laser power: 30mW
<Measurement sample>
Samples were cross-sectioned with a microtome after epoxy embedding.

(14) Melting point and glass transition point As a glass transition temperature differential scanning calorimeter, Seiko Electronics Co., Ltd. DSC RDC220,
The measurement was performed using a disk station SSC / 5200 manufactured by the same company as a data analysis apparatus. As measurement conditions, about 5 mg of a sample was sealed in an aluminum pan, held at 300 ° C. for 5 minutes, rapidly cooled with liquid nitrogen, and then measured at a temperature rising rate of 20 ° C./min.

(15) Identification of layer components As a method for analyzing the components of each layer, the micro infrared spectroscopic analyzer manufactured by SPECTRA-TECH: IRμs is used together with the above (14), and a silicon carbide rod heating element (global) is detected as a light source. The wave number range was 4000 to 650 cm ⁻¹ and the number of integrations was 500 to 1000 times, and the infrared spectrum of each layer was obtained using the transmission method.

  Next, although this invention is demonstrated based on an Example, this invention is not necessarily limited to these.

<Coating agent A>
85 parts by weight of dipentaerythritol hexaacrylate (DPHA: manufactured by Nippon Kayaku Co., Ltd.), 5 parts by weight of polyester acrylate (M-7100: manufactured by Toagosei Co., Ltd.), polyisocyanate (Sumidule N3300: manufactured by Sumika Bayer Urethane Co., Ltd.) ) 10 parts by weight of a mixed coating composition was prepared.

<Coating agent B>
A coating agent B was prepared in the same manner as the coating agent A except that no polyisocyanate was added.

<Coating C>
Coating agent A was adjusted to a concentration of 60 wt% with a mixed solvent in which toluene and methyl ethyl ketone were adjusted to have a weight ratio of 50:50, and coating agent C was obtained.

<Coating agent D>
85 parts by weight of dipentaerythritol hexaacrylate (DPHA: manufactured by Nippon Kayaku Co., Ltd.), 5 parts by weight of polyester acrylate (M-7100: manufactured by Toagosei Co., Ltd.), polyisocyanate (Sumijoule I: manufactured by Sumika Bayer Urethane Co., Ltd.) ) 10 parts by weight of a mixed coating composition was prepared.

<Coating E>
80 parts by weight of dipentaerythritol hexaacrylate (DPHA: manufactured by Nippon Kayaku Co., Ltd.), 5 parts by weight of polyester acrylate (M-7100: manufactured by Toagosei Co., Ltd.), polyisocyanate (Sumijoule I: manufactured by Sumika Bayer Urethane Co., Ltd.) ) A mixed coating composition of 10 parts by weight and 5 parts by weight of Sarohovic 100 (Fuji Silysia Chemical Co., Ltd.) was prepared.

<Coating agent F>
Dipentaerythritol hexaacrylate (DPHA: Nippon Kayaku Co., Ltd.) 70 parts by weight, polyester acrylate (M-7100: manufactured by Toagosei Co., Ltd.) 5 parts by weight, N-methyl-2-pyrrolidone 24 parts by weight, Irgacure 2959 ( 1 parts by weight of a mixed coating composition was produced.

(Example 1)
As a base material for a hard coat multilayer sheet, an intrinsic viscosity of 0.75 obtained by copolymerizing 98 wt% of polyethylene terephthalate (PET) having an intrinsic viscosity of 0.65 as polyester A and 30 mol% of 1,4-cyclohexanedimethanol with respect to ethylene glycol. 2 wt% of a copolymerized polyethylene terephthalate (30 mol% CHDM copolymerized PET) was used.

  As polyester B, copolymerized polyethylene terephthalate having an intrinsic viscosity of 0.75 obtained by copolymerizing 30 mol% of 1,4-cyclohexanedimethanol with ethylene glycol was used. Here, the copolymerization component X of the present invention is 1,4-cyclohexanedimethanol, and the component amount of X in the polyester A is 0.54 mol%. These polyesters A and B were dried and then fed to an extruder. The tensile modulus of polyester A was 1800 MPa, and the tensile modulus of polyester B was 1720 MPa.

  Polyesters A and B were each melted at 280 ° C. with an extruder, passed through a gear pump and a filter, and then joined with a feed block. The joined thermoplastic resins A and B were supplied to a static mixer to have a structure in which polyester A was alternately laminated in the thickness direction consisting of 16 layers and polyester B consisting of 15 layers, and both surface layer portions became polyester A. Here, the discharge amount was adjusted so that the lamination thickness ratio was A / B = 10.

  The laminate composed of 31 layers thus obtained was supplied to a T-die and formed into a sheet shape, and then rapidly cooled and solidified on a casting drum maintained at a surface temperature of 25 ° C. while applying electrostatic force.

  The obtained cast sheet is heated with a roll group set at 90 ° C., stretched 2.8 times in the longitudinal direction, and then a coating material of the above composition is uniformly applied to one side of the uniaxially stretched sheet to form a hard coat layer. This uniaxially stretched hard-coated multilayer sheet was guided to a tenter, preheated with hot air at 125 ° C., and then stretched 3.5 times in the transverse direction. The stretched film is further subjected to a relaxation treatment in the width direction of 5% continuously, subjected to a heat treatment for 24 seconds in a heat treatment zone at 230 ° C., cured and heat-set, and then gradually cooled to room temperature and wound up. It was. The hard coat multilayer sheet thus obtained had excellent transparency with a total thickness of 125 μm and a hard coat layer thickness of 5 μm. The results are shown in Table 1.

(Example 2)
In Example 1, a hard coat multilayer sheet was prepared in the same manner as in Example 1 except that the coating agent B containing no polyisocyanate was used instead of the coating agent A.
The results are shown in Table 1. The results are shown in Table 1 (Comparative Example 1).
On the surface of a biaxially oriented PET film (“Lumirror” (registered trademark) T60 (manufactured by Toray Industries, Inc.)) with a thickness of 150 μm cut to A4 size, an aqueous polyurethane resin was applied so that the thickness after drying was 1 μm, The primer layer was provided by drying at 150 ° C. for 1 minute. On the primer layer, coating agent C was applied so that the final lamination thickness was 25.0 μm, and then heat-treated at 120 ° C. for 1 minute, and then the film was fixed with a metal frame, and heat-treated at 230 ° C. for 1 minute. The coating film was cured and a hard coat film was prepared. As shown in Table 1, the surface waviness amplitude was 2.4%, the surface reflectance was 5.2%, and the haze was 0.8%, and the normal state adhesiveness was good, but the adhesiveness under wet heat was insufficient. . Also, the visibility was poor.

(Comparative Example 2)
A polyethylene terephthalate (hereinafter referred to as PET) (extreme viscosity 0.62 dl / g) chip containing 0.015% by weight of colloidal silica having an average particle size of 0.4 μm and 0.005% by weight of colloidal silica having an average particle size of 1.5 μm After sufficiently drying at 180 ° C. under vacuum, it is supplied to an extruder, melted at 285 ° C., extruded from a T-shaped die into a sheet shape, and applied to a mirror cast drum having a surface temperature of 20 ° C. using an electrostatic application casting method. It was wound and solidified by cooling to obtain an unstretched sheet. The unstretched sheet thus obtained was stretched 3.5 times in the longitudinal direction with a roll group heated to 95 ° C. to obtain a uniaxially stretched film. The coating agent F described above was applied to one side of this uniaxially stretched film in a thickness of 35 μm by a die coating method. While holding both ends of the film coated with coating agent A with clips, the film was guided to a preheating zone at 90 ° C., and subsequently stretched 3.3 times in the width direction in a heating zone at 100 ° C. Furthermore, with a high pressure mercury lamp having an irradiation intensity of 120 W / cm set to a height of 9 cm from the coated surface, subjected to a heat treatment for 10 seconds in a heat treatment zone of 210 ° C. while continuously relaxing in the width direction of 3%. Ultraviolet rays were irradiated for 5 seconds in a nitrogen atmosphere to cure the coating film. The hard coat film thus obtained was excellent in transparency with a total thickness of 125 μm and a hard coat layer thickness of 5 μm. The results are shown in Table 1. As shown in Table 1, in comparison with the Examples, only 1/5 or less tear strength was obtained.

(Comparative Example 3)
A biaxially oriented PET film (“Lumirror” (registered trademark) T60 (manufactured by Toray Industries, Inc.)) having a thickness of 150 μm cut into an A4 size. A hard coat layer was not provided. As shown in Table 1, the surface waviness amplitude was 0%, the surface reflectance was 7.2%, and the haze was 0.8%, but the wear resistance and pencil hardness were poor.

(Comparative Example 4)
A multi-layer sheet having a thickness of 150 μm was prepared by the same method as in Example 1, and no hard coat layer was provided. The results are shown in Table 1.

(Example 3)
In Example 1, a hard-coated multilayer sheet was prepared in the same manner as in Example 1 except that instead of the coating A, the coating D in which the polyisocyanate was changed was used. The results are shown in Table 1.

Example 4
In Example 1, a hard coat multilayer sheet was prepared in the same manner as in Example 1 except that the coating E was used instead of the coating A. The results are shown in Table 1. The results are shown in Table 1.

  The hard coat multilayer sheet of the present invention thus obtained can be provided with a hard coat layer all at once in the film forming process, so that the productivity is good, the surface hardness is high, the wear resistance is excellent, the hard coat layer. And the substrate film are excellent in adhesion, and the generation of iris patterns is suppressed and the visibility is excellent, so that it can be used in a wide range of applications. In particular, it can be suitably used as a base material for a touch panel, a base material for a nameplate, etc., but its application range is not limited to these.

Schematic of the hard coat multilayer sheet of the present invention Schematic of hard coat multilayer sheet of the present invention (combination of hard coat multilayer sheet and aqueous coating) Wavelength / reflectance graph showing the waviness amplitude of reflectance

Explanation of symbols

1 Hard coat layer (b layer)
2 Polyester B (B layer) constituting the base material multilayer sheet (a layer)
3 Polyester A (A layer) constituting the base material multilayer sheet (a layer)
4 Polyester C (C layer) constituting the base material multilayer sheet (a layer)
5 Easily slippery / adhesive layer (water-based coating material)
6 Summit line 7 Valley bottom line 8 Hard coat layer side reflectance curve 9 Waviness amplitude

Claims (11)

A hard coat multilayer sheet comprising a substrate multilayer sheet (a) having a laminated structure and a hard coat layer (b), wherein the substrate multilayer sheet (a) comprises a polyester (A) as a main component (A layer) And the average swell amplitude of the reflectance of the hard coat layer (b) when it is irradiated with light having a wavelength of 400 to 660 nm. Hard coat multilayer sheet characterized by being 1% or less. The hard coat multilayer sheet according to claim 1, wherein the polyester (A) constituting the A layer is a crystalline polymer, and the polyester (B) constituting the B layer is an amorphous polymer. Polyester (A) contains at least three diol derivatives containing at least one component (component X) selected from the group consisting of 1,4-cyclohexanedimethanol, bisphenol A ethylene oxide adduct, dimer acid, and polyalkylene dicarboxylic acid The hard-coated multilayer sheet according to claim 1, wherein the hard coat multilayer sheet is composed of 0.1 to 10 mol% of the component X in the polyester A. Polyester (B) contains at least three diol derivatives containing at least one component (component X) selected from the group consisting of 1,4-cyclohexanedimethanol, bisphenol B ethylene oxide adduct, dimer acid, and polyalkylene dicarboxylic acid The hard coat multilayer sheet according to any one of claims 1 to 3, wherein the hard coat multilayer sheet is composed of a dicarboxylic acid derivative and the component X is contained in the polyester B in an amount of 10 to 60 mol%. The hard coat multilayer sheet according to any one of claims 1 to 4, wherein the hard coat layer has a surface reflectance of 6% or less and a haze of the hard coat multilayer sheet is 6% or less. . The hard coat multilayer sheet according to claim 1, wherein the hard coat layer contains an acrylate cured product as a main component. The base material multilayer sheet is composed of 31 to 128 layers, and at least one layer of the base material multilayer sheet contains polyester having 1,4-cyclohexanedimethanol as a constituent component. The hard coat multilayer sheet according to any one of 1 to 6. The glass protective sheet which uses the hard coat multilayer sheet in any one of Claims 1-7. An antireflection sheet comprising the hard coat multilayer sheet according to claim 1. A building material window glass using the glass protective sheet according to claim 8. A flat panel display using an antireflection sheet using the hard coat multilayer sheet according to claim 9.

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