JP4650604B2 - UV-absorbing polyester film for plasma display and filter for plasma display panel using the same - Google Patents

Description

The present invention relates to a filter for a plasma display panel. Specifically, it has a function to prevent deterioration due to ultraviolet rays contained in the sunlight of the near-infrared absorption layer installed on the front of the display for the purpose of preventing malfunctions in remote control and transmission optical communication due to near-infrared rays emitted from the plasma display. The present invention relates to a filter for a plasma display panel.

  In recent years, plasma display panels have been used as display panels for various types of electronic devices such as large-sized wall-mounted televisions. The demand for these panels has increased, and the number is expected to increase in the future.

  A filter for a plasma display panel includes a near-infrared cut layer and an electromagnetic wave cut layer, or a combination of an antireflection layer and a glare prevention (non-glare) layer for preventing external light such as a fluorescent lamp from being reflected on the surface.

  In particular, the near-infrared cut layer is installed on the front of the display and has an important function for the purpose of preventing malfunctions in remote control and transmission optical communication due to near-infrared rays emitted from the plasma display.

However, included in the near-infrared absorption layer, for example, near infrared absorbing dye, including near infrared absorbing dye containing a diimmonium compound and a fluorine-containing phthalocyanine compound based decomposes generally by ultraviolet rays contained in sunlight, its performance is long There was a problem that it decreased with the use of the period.

  For this reason, a method has been proposed in which a layer containing an ultraviolet absorber is applied to the base film by coating.

For example, in Japanese Patent Laid-Open No. 2002-71942 (Patent Document 1), an ultraviolet absorbing layer (2- (2′-hydroxy-3 ′, 5′-di-t-butylphenyl) is coated on one side of a filter for a plasma display panel by coating. )) 0.36 g of a 0.63% cyclohexanone solution of benzotriazole and 3 g of a 20% cyclohexanone solution of polyethylene terephthalate resin (Byron 200; manufactured by Toyobo Co., Ltd.), coated with a bar coater, and dried. Although a method of laminating a coating film having a film thickness of 6 μm is exemplified, it cannot have an ultraviolet shielding effect sufficient to prevent deterioration of the near-infrared absorbing dye.

Japanese Patent Laid-Open No. 2003-1703 (Patent Document 2) exemplifies a method of kneading an ultraviolet absorber directly into a base film, and according to this method, deterioration of a near-infrared absorbing dye is prevented. In addition, a sufficient ultraviolet shielding effect can be obtained. However, the exemplified cyclic imino ester-based UV absorber is a suitable material that is less likely to sublime than a general UV absorber, but when it is melt-extruded in the resin extrusion process, Since it is not zero and has the property of bleeding out to the film surface layer, sublimates and the like adhere to the take-up roll although it is in a small amount. This adhered UV absorber contaminates the process with the passage of film formation time, adheres to the film, becomes a foreign matter defect, adheres to preheating, stretching and cooling rolls in the subsequent longitudinal stretching process, and generates scratches, etc. Cause problems. For this reason, periodic roll cleaning work is disadvantageous in terms of cost. Further, in order to avoid this problem, the method of melting and extruding the resin at a low temperature raises the filtration pressure on the filter, which causes problems such as difficulty in high-precision filtration.

  Moreover, since it is exposed to a high temperature even in the transverse stretching step, the ultraviolet absorber sublimates, accumulates in the tenter for a long time, and then drops and adheres to the film, resulting in a foreign matter defect. These foreign matter defects, scratches, and the like become fatal defects particularly for optical films with strict requirements.

In other words, it has a sufficient ability to prevent deterioration of near-infrared absorbing dyes, is free of process contamination such as roll stains, is excellent in productivity, and has excellent adhesion to the near-infrared absorbing layer and the hard coat layer. Production of the material film and the filter for the plasma display panel has been difficult.
JP 2002-71942 A JP 2003-1703 A

In view of the above problems, for sufficient while maintaining the deterioration prevention performance of the near infrared absorbing dye coloration less, excellent productivity without process contamination such as roll staining, further near-infrared absorption layer and the hard coat layer An object of the present invention is to provide a plasma display panel filter base film and a plasma display panel filter excellent in adhesiveness .

The present invention has been made in view of the above circumstances, and its main purpose is to maintain adhesion to the near infrared absorbing layer and the hard coat layer with little coloring while maintaining sufficient near infrared absorbing dye deterioration preventing performance. An object of the present invention is to provide a plasma display panel filter substrate film and a plasma display panel filter which are excellent and have few optical defects due to roll contamination due to sublimation of a UV agent.

  As a result of diligent research to achieve the above-mentioned problems, a substrate film for a plasma display panel filter and a plasma display panel filter that have solved the above problems have been obtained.

That is, the present invention has the following configuration.
A:
(1) The polyester film substrate is a biaxially oriented laminated polyester film substrate having a laminated structure of three or more layers, (2) has an easy-adhesion layer on both surfaces of the substrate film, and (3) at least intermediate A plasma display characterized in that the layer contains an ultraviolet absorber, (4) the absorbance and adhesion satisfy the following formula, and (5) the thickness of one outermost layer is 3 to 15% of the total thickness UV-absorbing polyester film.
abs (≦ 380) ≧ 2
adH ≧ 85
adNIR ≧ 85
Where abs (≦ 380) is the absorbance at a wavelength of 380 nm or less,
adH has adhesiveness when a photo-curing acrylic coat layer is provided on the easy-adhesion layer.
adNIR represents the adhesiveness when a near-infrared absorbing layer is provided on an easily adhesive layer.
B:
The intermediate layer of the biaxially oriented laminated polyester film substrate having a laminated structure of three or more layers contains at least one ultraviolet absorber selected from the group consisting of benzotriazole-based and cyclic iminoester-based, The ultraviolet-absorbing polyester film for plasma display according to Item A, which is substantially free of particles.
C:
A filter for plasma display having a near-infrared absorbing layer on at least one side of the ultraviolet absorbing polyester film for plasma display of Item B.
D:
The plasma according to items A, B and C, wherein the ratio of the absorbance (X) of the base polyester film surface layer measured by FT-IR and the absorbance (Y) at the center of the film satisfies the following formula: UV absorbing polyester film for display panels.
0 ≦ X / Y ≦ 0.1
X: Blank sample (polyethylene terephthalate containing no UV absorber (PET
) The IR spectrum (I) of the surface layer of the film) and the surface IR spectrum (II) of the sample of the present invention are measured.

Taking the difference spectrum of (I) and (II), the absorbance at 1760 cm ⁻¹ (characteristic absorption of the UV absorber used) and the absorption at 1505 cm ⁻¹ obtained from the IR spectrum of (II) (PET The absorbance ratio (1760 cm ⁻¹ / 1505 cm ⁻¹ ) and X was determined.

Y: 50% of the total thickness of the sample of the present invention was shaved off in the thickness direction, and the exposed surface (film central portion) was measured to make (II). Asked.
E:
Both outermost layers of the biaxially oriented laminated polyester film base material contain at least one polymer ultraviolet absorber, the adhesiveness satisfies the following formula, and all three layers are substantially other than the ultraviolet absorber. The UV-absorbing polyester film for plasma display according to item A, B, C, or D, characterized in that it contains no particles.
adH2 ≧ 85
adH2 = Adhesiveness after photocuring acrylic coating layer is provided on easy-adhesion layer of substrate film and irradiated with sunshine weather meter for 500 hours

According to the present invention, there is little coloring while maintaining sufficient near-infrared absorbing dye deterioration preventing performance, and further excellent adhesion to the near-infrared absorbing layer and the hard coat layer, and optical caused by contamination of the roll due to sublimation of the UV agent. It is possible to provide a substrate film for a plasma display panel filter and a plasma display panel filter with few defects.

  The ultraviolet-absorbing polyester film for plasma display of the present invention comprises a polyester film having an easy-adhesion layer on both sides and containing an ultraviolet absorber. Examples of the polyester film include polyethylene terephthalate, polybutylene terephthalate, polyethylene-2,6-naphthalate, or a film made of a copolymer mainly composed of components of these resins. Among these, A biaxially stretched polyethylene terephthalate film is particularly suitable from the viewpoints of mechanical properties, heat resistance, transparency, price, and the like.

  From the viewpoint of excellent strength, dimensional stability, and ease of handling, the base film of the plasma display panel filter can be a biaxially oriented thermoplastic resin film with a thickness of 50 μm or more. Is not particularly limited. The upper limit of the thickness of the base film is not particularly limited, but it is recommended that the thickness is 300 μm or less from the viewpoint of handling properties and specifications as an optical member.

  When using a copolymer, the dicarboxylic acid component includes aliphatic dicarboxylic acids such as adipic acid and sebacic acid; aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid, and 2,6-naphthalenedicarboxylic acid; trimellito Polyfunctional carboxylic acids such as acid and pyromellitic acid are used. The glycol component includes fatty acid glycols such as ethylene glycol, diethylene glycol, 1,4-butanediol, propylene glycol and neopentyl glycol; aromatic glycols such as p-xylene glycol; alicyclic rings such as 1,4-cyclohexanedimethanol Group glycol; polyethylene glycol having an average molecular weight of 150 to 20,000 is used.

  The weight ratio of the copolymer component of the preferred copolymer is less than 20% by weight. If it is 20% by weight or more, the film strength, transparency, and heat resistance tend to be inferior.

  Moreover, the intrinsic viscosity of the resin pellet used for the polyester film of the present invention is preferably in the range of 0.45 to 0.70 dl / g.

  When the intrinsic viscosity is lower than 0.45 dl / g, the tear resistance improving effect tends to deteriorate. On the other hand, if the intrinsic viscosity is greater than 0.70 dl / g, the increase in filtration pressure tends to be large and high-precision filtration tends to be difficult.

As will be described later, the base film according to the present invention is usually melt-extruded into a film and cast by a metal roll to form a film. In this casting, it is recommended to make electrostatic contact in order to improve the adhesion between the molten film and the metal roll. Therefore, it is desirable that the polyester resin constituting the base material has a low melting specific resistance value. Specifically, the melt specific resistance value at 275 ° C. of the polyester resin is preferably 0.45 × 10 ⁸ Ω · cm or less, more preferably 0.30 × 10 ⁸ Ω · cm or less. . On the other hand, if the melt specific resistance value of the polyester resin is too low, the base film tends to be affected by static electricity and the handling property tends to be lowered. Therefore, the melt specific resistance value of the polyester resin at 275 ° C. is preferably 0.10 × 10 ⁸ Ω · cm or more, and more preferably 0.12 × 10 ⁸ Ω · cm or more.

  In addition, the melt specific resistance value prescribed | regulated by this invention is a value measured by the method employ | adopted in the Example mentioned later.

  The melt specific resistance value of the polyester resin can be ensured by including a magnesium compound and a phosphorus compound in the polyester resin.

  Magnesium in the magnesium compound has an action of lowering the melt specific resistance value of the polyester resin. From the viewpoint of effectively exhibiting such an action and suppressing the generation of foreign matters due to the magnesium compound and the coloration of the polyester resin, the amount of the magnesium compound in the polyester resin is 40 ppm in terms of magnesium atom (mass basis, the same applies hereinafter). Above, preferably 45 ppm or more and 70 ppm or less, preferably 65 ppm or less is recommended.

  The phosphorus compound itself does not have an action of lowering the melt specific resistance value of the polyester resin, but it can contribute to the reduction of the melt specific resistance value when combined with the magnesium compound. The reason for this is not clear, but it is thought that the inclusion of a phosphorus compound can suppress the generation of foreign substances and increase the amount of charge carriers. Therefore, the amount of the phosphorus compound in the polyester resin is 10 ppm (mass basis, the same shall apply hereinafter) or more, preferably in terms of phosphorus atom, from the viewpoint of effectively exhibiting the above-described action and suppressing the generation of foreign matters due to the phosphorus compound. It is recommended that it be 15 ppm or more and 55 ppm or less, preferably 50 ppm or less.

  In this invention, you may include the particle | grains for providing slipperiness in a base film. In this case, the particles may be included in each of the intermediate layer and the outermost layer of the base film, but it is preferable that the particles are included only in the outermost layer from the viewpoint of transparency. Examples of the particles in this case include calcium carbonate, calcium oxide, ammonium oxide, calcium phosphate, silica, zinc oxide, silicon carbide, kaolin, talc, titanium dioxide, alumina, barium sulfate, calcium fluoride, lithium fluoride, zeolite, and sulfide. Examples thereof include inorganic particles such as molybdenum, crosslinked polymer particles, and organic particles such as calcium oxalate. Of these, silica is most preferable because it has a relatively close refractive index to that of the polyester resin and can easily provide high transparency. The average particle diameter of silica is preferably 1 to 3 μm, and the addition amount is preferably 0.003 to 0.01% by weight from the viewpoint of transparency and slipping.

  Moreover, in order to ensure further high transparency, it is preferable that the particle | grains for providing slipperiness in a base film do not exist substantially. Note that “substantially no particles” means that the amount of particles present in the base material on which the adhesive-modified resin layer is not laminated is below the detection limit of fluorescent X-ray analysis.

  Even if particles for the purpose of imparting slipperiness are not added to the polyester base film, it is good if the easy-adhesion layer laminated in-line is made slippery by containing fine particles with a uniform particle size. Addition of particles to the polyester base film is unnecessary because it can provide a roll-up property and a scratch generation preventing function.

  Examples of particles to be included in such an easy-adhesion layer include calcium carbonate, calcium phosphate, silica, kaolin, talc, titanium dioxide, alumina, barium sulfate, calcium fluoride, lithium fluoride, zeolite, molybdenum sulfide, and other inorganic particles, Examples thereof include organic particles such as crosslinked polymer particles and calcium oxalate. Among these, silica is most preferable because it has a relatively close refractive index to that of the polyester resin and can easily obtain high transparency.

  The ultraviolet absorber used in the method of the present invention is a known substance.

  First, examples of the ultraviolet absorber added to the intermediate layer of the biaxially oriented laminated polyester film base material having a laminate structure of three or more layers include organic ultraviolet absorbers and inorganic ultraviolet absorbers. From the viewpoint, an organic ultraviolet absorber is preferred. The intermediate layer in this case refers to at least one layer other than both outermost layers.

  Furthermore, examples of the organic ultraviolet absorber include benzotoazoles, benzophenones, cyclic iminoesters, and the like, and combinations thereof. However, the organic ultraviolet absorbers are not particularly limited as long as they are within the absorbance range defined in the present invention. However, from the viewpoint of durability, benzotoazole and cyclic imino ester are particularly preferable.

  When two or more kinds of ultraviolet absorbers are used in combination, ultraviolet rays having different wavelengths can be absorbed simultaneously, so that the ultraviolet absorption effect can be further improved.

  Examples of the benzotriazole ultraviolet absorber include 2- [2′-hydroxy-5 ′-(methacryloyloxymethyl) phenyl] -2H-benzotriazole and 2- [2′-hydroxy-5 ′-(methacryloyloxyethyl). Phenyl] -2H-benzotriazole, 2- [2′-hydroxy-5 ′-(methacryloyloxypropyl) phenyl] -2H-benzotriazole, 2- [2′-hydroxy-5 ′-(methacryloyloxyhexyl) phenyl] -2H-benzotriazole, 2- [2'-hydroxy-3'-tert-butyl-5 '-(methacryloyloxyethyl) phenyl] -2H-benzotriazole, 2- [2'-hydroxy-5'-tert- Butyl-3 ′-(methacryloyloxyethyl) phenyl] -2H-benzotriazol 2- [2′-hydroxy-5 ′-(methacryloyloxyethyl) phenyl] -5-chloro-2H-benzotriazole, 2- [2′-hydroxy-5 ′-(methacryloyloxyethyl) phenyl] -5 Methoxy-2H-benzotriazole, 2- [2′-hydroxy-5 ′-(methacryloyloxyethyl) phenyl] -5-cyano-2H-benzotriazole, 2- [2′-hydroxy-5 ′-(methacryloyloxyethyl) ) Phenyl] -5-tert-butyl-2H-benzotriazole, 2- [2′-hydroxy-5 ′-(methacryloyloxyethyl) phenyl] -5-nitro-2H-benzotriazole, and the like. It is not limited to.

  Examples of the cyclic imino ester-based ultraviolet absorber include, but are not limited to, the following.

  2,2 ′-(1,4-phenylene) bis (4H-3,1-benzoxazinon-4-one), 2-methyl-3,1-benzoxazin-4-one, 2-butyl-3, 1-benzoxazin-4-one, 2-phenyl-3,1-benzoxazin-4-one, 2- (1- or 2-naphthyl) -3,1-benzoxazin-4-one, 2- (4 -Biphenyl) -3,1-benzoxazin-4-one, 2-p-nitrophenyl-3,1-benzoxazin-4-one, 2-m-nitrophenyl-3,1-benzoxazin-4-one 2-p-benzoylphenyl-3,1-benzoxazin-4-one, 2-p-methoxyphenyl-3,1-benzoxazin-4-one, 2-o-methoxyphenyl-3,1-benzoxazine -4-one, 2 Cyclohexyl-3,1-benzoxazin-4-one, 2-p- (or m-) phthalimidophenyl-3,1-benzoxazin-4-one, 2,2 ′-(1,4-phenylene) bis ( 4H-3,1-benzoxazinon-4-one) 2,2′-bis (3,1-benzoxazin-4-one), 2,2′-ethylenebis (3,1-benzoxazine-4-one) ON), 2,2′-tetramethylenebis (3,1-benzoxazin-4-one), 2,2′-decamethylenebis (3,1-benzoxazin-4-one), 2,2′- p-phenylenebis (3,1-benzoxazin-4-one), 2,2'-m-phenylenebis (3,1-benzoxazin-4-one), 2,2 '-(4,4'- Diphenylene) bis (3,1-benzoxazine 4-one), 2,2 ′-(2,6- or 1,5-naphthalene) bis (3,1-benzoxazin-4-one), 2,2 ′-(2-methyl-p-phenylene) Bis (3,1-benzoxazin-4-one), 2,2 '-(2-nitro-p-phenylene) bis (3,1-benzoxazin-4-one), 2,2'-(2- Chloro-p-phenylene) bis (3,1-benzoxazin-4-one), 2,2 ′-(1,4-cyclohexylene) bis (3,1-benzoxazin-4-one).

  1,3,5-tri (3,1-benzoxazin-4-on-2-yl) benzene, 1,3,5-tri (3,1-benzoxazin-4-on-2-yl) naphthalene, And 2,4,6-tri (3,1-benzoxazin-4-one-2-yl) naphthalene.

  2,8-dimethyl-4H, 6H-benzo (1,2-d; 5,4-d ′) bis- (1,3) -oxazine-4,6-dione, 2,7-dimethyl-4H, 9H -Benzo (1,2-d; 5,4-d ') bis- (1,3) -oxazine-4,9-dione, 2,8-diphenyl-4H, 8H-benzo (1,2-d; 5,4-d ') bis- (1,3) -oxazine-4,6-dione, 2,7-diphenyl-4H, 9H-benzo (1,2-d; 5,4-d') bis- (1,3) -Oxazine-4,6-dione, 6,6′-bis (2-methyl-4H, 3,1-benzoxazin-4-one), 6,6′-bis (2-ethyl- 4H, 3,1-benzoxazin-4-one), 6,6′-bis (2-phenyl-4H, 3,1-benzoxazin-4-one), 6,6′-methylene (2-methyl-4H, 3,1-benzoxazin-4-one), 6,6′-methylenebis (2-phenyl-4H, 3,1-benzoxazin-4-one), 6,6′- Ethylenebis (2-methyl-4H, 3,1-benzoxazin-4-one), 6,6′-ethylenebis (2-phenyl-4H, 3,1-benzoxazin-4-one), 6,6 '-Butylenebis (2-methyl-4H, 3,1-benzoxazin-4-one), 6,6'-Butylenebis (2-phenyl-4H, 3,1-benzoxazin-4-one), 6,6 '-Oxybis (2-methyl-4H, 3,1-benzoxazin-4-one), 6,6'-oxybis (2-phenyl-4H, 3,1-benzoxazin-4-one), 6,6 '-Sulfonylbis (2-methyl-4H, 3,1-benzene Nzooxazin-4-one), 6,6′-sulfonylbis (2-phenyl-4H, 3,1-benzoxazin-4-one), 6,6′-carbonylbis (2-methyl-4H, 3,1) -Benzoxazin-4-one), 6,6'-carbonylbis (2-phenyl-4H, 3,1-benzoxazin-4-one), 7,7'-methylenebis (2-methyl-4H, 3, 1-benzoxazin-4-one), 7,7′-methylenebis (2-phenyl-4H, 3,1-benzoxazin-4-one), 7,7′-bis (2-methyl-4H, 3, 1-benzoxazin-4-one), 7,7′-ethylenebis (2-methyl-4H, 3,1-benzoxazin-4-one), 7,7′-oxybis (2-methyl-4H, 3) , 1-benzoxazin-4-one), 7,7 -Sulfonylbis (2-methyl-4H, 3,1-benzoxazin-4-one), 7,7'-carbonylbis (2-methyl-4H, 3,1-benzoxazin-4-one), 6, 7′-bis (2-methyl-4H, 3,1-benzoxazin-4-one), 6,7′-bis (2-phenyl-4H, 3,1-benzoxazin-4-one), 6, 7'-methylenebis (2-methyl-4H, 3,1-benzoxazin-4-one) and 6,7'-methylenebis (2-phenyl-4H, 3,1-benzoxazin-4-one).

  Further, it is preferable to use an ultraviolet absorber having a decomposition start temperature of 290 ° C. or higher in order to reduce process contamination during film formation.

  The addition amount of the ultraviolet absorber is preferably 0.1 to 4% by weight, more preferably 0.3 to 2% by weight, based on the polyester. If this amount is less than 0.1% by weight, the effect of preventing UV deterioration is small, and if it exceeds 4% by weight, the film turns yellow or the film-forming property of the polyester film decreases, which is not preferable.

  A combination of known methods can be employed as a method of blending the base film with the ultraviolet absorber.

  For example, by using a kneading extruder in advance, blending the dried UV absorber and the polyester raw material to prepare a master batch, and by mixing the predetermined master batch and the polyester raw material when forming the base film Can be blended.

  At this time, the concentration of the UV absorber in the master batch is preferably 5 to 30% by weight in order to uniformly disperse the UV absorber and economically blend it. As a condition for producing the master batch, it is preferable to use a kneading extruder and to extrude it at a temperature not lower than the melting point of the polyester raw material and not higher than 290 ° C. for 1 to 15 minutes. If it exceeds 290 ° C., the weight loss of the UV absorber is large, and the viscosity of the master batch is greatly reduced. If the extrusion temperature is less than 1 minute, uniform mixing of the UV absorber becomes difficult. At this time, if necessary, a stabilizer, a color tone adjusting agent, and an antistatic agent may be added.

  Next, both outermost layers of the biaxially oriented laminated polyester film base material having a laminated structure of three or more layers are laminated for the purpose of preventing sublimates of the ultraviolet absorber contained in the intermediate layer and preventing bleeding out. The About the lamination | stacking ratio in this case, 3-15% is preferable and, as for the ratio with respect to the total thickness of the outermost layer (one side), 5-10% is more preferable. When the ratio of the outermost layer (one side) is lower than 3%, sublimation and bleeding out of the organic ultraviolet absorber contained in the intermediate layer cannot be sufficiently prevented. On the other hand, if it is higher than 15%, the UV absorption effect of the intermediate layer may be insufficient, which is not preferable.

Both outermost layers do not necessarily contain an ultraviolet absorber. However, in this case, the outermost layer that does not contain the ultraviolet absorber is deteriorated by ultraviolet rays, and sufficient adhesiveness to the near-infrared absorbing layer and the hard coat layer may not be obtained over time.

  In order to solve these problems, it is preferable to add a polymer type ultraviolet absorber that does not cause a problem of bleeding on the surface layer. The polymer type ultraviolet absorber is a known substance.

  The polymer type ultraviolet absorber is a polymer having a skeleton useful as an ultraviolet absorber in the side chain. Although it will not specifically limit if the transmittance | permeability of the light with a wavelength of 350 nm or less will be 5% or less, A polyester type and an acrylic polymer ultraviolet absorber are mainly preferable from compatibility with a polyester resin.

  For example, the polyester resin is a polyester mainly composed of terephthalic acid as a dicarboxylic acid component, ethylene glycol and / or 1,4-butanediol as a diol component, and naphthalene represented by the general formula (I) as a copolymerization component UV-absorbing compound containing tetracarboxylic acid diimide and naphthalenedicarboxylic acid represented by the general formula (II) (Novapex U-110 manufactured by Mitsubishi Chemical Corporation), acrylic having 2- (2-hydroxylphenyl) benzotriazole skeleton in the side chain Properties such as UV-cutting performance and transparency, which are aimed for by a polymer based (UVA-1635 manufactured by BASF), are preferred.

(In the above general formula (I), R represents an alkylene group, X represents a hydroxy group, etc.)

The addition amount of the polymer type ultraviolet absorber is preferably 0.1 to 20% by weight, more preferably 0.5 to 15% by weight, based on the polyester. If the amount is less than 0.1% by weight, the effect of preventing UV deterioration is small, and if it exceeds 20% by weight, the film is yellowed or the film forming property of the polyester film is lowered, which is not preferable.

  As a method of blending the ultraviolet absorber into the base film, a known method can be used in combination in the same manner as the ultraviolet absorber contained in the intermediate layer.

  The thermoplastic resin, which is a constituent material of the base material, may contain various additives as long as it does not hinder the action of the present invention. Examples of the additive include an antistatic agent and a stabilizer.

  Next, the method for producing an ultraviolet-absorbing polyester film for plasma display of the present invention will be described in detail with respect to an example in which polyethylene terephthalate (hereinafter referred to as PET) pellets are used as the raw material of the base film, but it is naturally limited to this. It is not a thing.

  In general, the pellets are transported by air using a predetermined pipe. In this case, it is preferable to use purified air using a HEPA filter in order to prevent dust contamination.

  The HEPA filter used at this time is preferably a filter having a performance of cutting 95% or more of dust having a nominal filtration accuracy of 0.5 μm or more.

  First, a PET pellet, an ultraviolet absorber, and a polyester raw material are blended, and a master batch is mixed at a predetermined ratio. The PET pellet and the master batch obtained by blending the ultraviolet absorber and the polyester raw material are pellets substantially free of particles for the purpose of imparting slipperiness. The mixed raw material pellets are sufficiently dried in vacuum, then supplied to an extruder, melted and extruded into a sheet, and cooled and solidified on a casting roll to form an unstretched PET sheet. In this case, it is UV absorption that the resin temperature to the extruder melt section, kneading section, polymer tube, gear pump, and filter is 280 to 290 ° C, and the resin temperature to the subsequent polymer tube and flat die is 270 to 280 ° C. It is preferable in order to prevent sublimation at the outlet of the agent and contamination of the take-up roll. In addition, high-precision filtration is performed at any place where the molten resin is maintained at about 280 ° C. in order to remove foreign substances contained in the resin. The filter medium used for high-precision filtration of the molten resin is not particularly limited, but in the case of a stainless steel sintered filter medium, the removal performance of aggregates and high melting point organic substances mainly composed of Si, Ti, Sb, Ge, Cu Excellent and suitable.

  When high-precision filtration is performed, if the temperature of the molten resin is lower than 280 ° C., the filtration pressure rises, so that it is necessary to take measures such as reducing the extrusion amount, and productivity is lowered.

  Further, the filter particle size (initial filtration efficiency 95%) of the filter medium is preferably 20 μm or less, particularly preferably 15 μm or less. When the filter particle size of the filter medium (initial filtration efficiency 95%) exceeds 20 μm, foreign matters having a size of 20 μm or more cannot be sufficiently removed. By performing high-precision filtration of the molten resin using a filter medium having a filter particle size (initial filtration efficiency of 95%) of 20 μm or less, productivity may be reduced, but a film with few protrusions due to coarse particles is obtained. This is an important process.

  When foreign materials existing in the raw material polymer and UV absorbers sublimate and contaminate the rolls, and there are those attached to the film, the orientation of the polyester molecules is disturbed around these foreign materials in the stretching process during film formation, and optical Distortion occurs. Because of this optical distortion, it is recognized as a defect that is considerably larger than the actual size of the foreign material, so that the quality is significantly impaired. For example, a foreign substance having a size of 20 μm may be optically recognized as a size of 50 μm or more, and may be recognized as an optical defect having a size of 100 μm or more. In order to obtain a highly transparent film, it is desirable not to contain particles for imparting slipperiness in the base film, or to contain only a small amount so as not to inhibit transparency, but the particle content is low. As the transparency of the film increases, optical defects due to minute foreign substances tend to become clearer. Further, as the film becomes thicker, the content of foreign matters per unit area of the film tends to be larger than that of a thin film, and this problem is further increased.

  On the other hand, in order to increase the transparency of the film, if the base film does not contain particles, or if it is contained only in a small amount so as not to impair the transparency, the slipperiness of the film becomes insufficient and the handling properties deteriorate. . Therefore, it is necessary to add particles for the purpose of imparting slipperiness to the easy-adhesion layer, and these particles need to use particles having an extremely small average particle diameter equal to or smaller than the wavelength of visible light in order to ensure transparency. is there. However, these fine particles tend to be coarse aggregates, and if an easy-adhesion layer containing the coarse aggregates is laminated on the base film, optical defects are caused.

The base film surface has a shape in which the height of the convex part is 1 μm or more and the maximum diameter is 20 μm or more, and a foreign substance having a concave part depth of 100 μm or less from a position adjacent to the convex part is 0.5 μm or more. It is preferably 10 pieces / m ² or less, and more preferably 5 pieces / m ² .

  Next, PET pellets alone for the outermost layer, master batches containing UV absorbers for the intermediate layer and PET pellets are mixed at a predetermined ratio, dried, and then supplied to a known melt laminating extruder, Extruded into a sheet form from a slit-shaped die and cooled and solidified on a casting roll to make an unstretched film. That is, using two or more extruders, a three-layer manifold or a merging block (for example, a merging block having a square merging portion), a film layer constituting both outer layers and a film layer constituting an intermediate layer are laminated, An unstretched film is formed by extruding a three-layer sheet from the die and cooling with a casting roll. About the lamination | stacking ratio in this case, 3-15% is preferable and, as for the ratio with respect to the total thickness of the outermost layer (one side), 5-10% is more preferable. When the ratio of the outermost layer (one side) is lower than 3%, the bleeding out of the organic ultraviolet absorber contained in the intermediate layer cannot be sufficiently prevented. On the other hand, if it is higher than 15%, the UV absorption effect of the intermediate layer may be insufficient, which is not preferable.

  For the purpose of preventing UV degradation of the outermost layer, it is preferable to add a known polymer type UV absorber that does not have a bleeding problem in the outermost layer.

  The obtained unstretched film is stretched 2.5 to 5.0 times in the longitudinal direction (longitudinal direction: traveling direction during production of the laminated film) with a roll heated to 80 to 120 ° C. to obtain a uniaxially oriented film. In addition, the process of performing this uniaxial stretching may be called "longitudinal stretching process".

Scratches having a depth of 1 μm or more and a length of 3 mm or more present on the surface of the laminated film are 100 pieces / m ² or less. Preferably, the number of scratches is 30 / m ² or less, more preferably 10 / m ² or less. If the number of scratches is within such a range, problems due to optical defects do not occur.

Of course, in the laminated film of the present invention, the number of scratches is most preferably 0 / m ² .

More specifically, the number of the vertical scratches or the horizontal scratches is 50 / m ² or less, preferably 30 / m ² or less, more preferably 15 / m ² or less, and even more preferably 10 pieces / m ² or less, particularly preferably 5 / m ² or less, it is recommended that the most preferably 0 / m ^2. It is more desirable that both the vertical scratch and the horizontal scratch satisfy the number range.

  In this case, in order to prevent the generation of scratches on the film, (a) the film surface itself or the roll surface, in particular, the roll surface in contact with the film should not generate “defects” that cause scratches, and (b) contact. It is important that the film does not shift in the machine and transverse directions on the surface of the roll to be rolled.

  The above-mentioned “defects” refer to all factors that cause fine scratches on the film by coming into contact with the film, such as scratches, deposits, deposits, and foreign matters formed on the roll surface. Therefore, by eliminating these defects, it is possible to reduce the occurrence of scratches on the film surface. In order to prevent the occurrence of the above defects, for example, the following methods can be employed.

  In order to prevent the surface roughness of the roll used in the production of the laminated film from 0.1 μm or less by Ra, or to prevent the generation of scratches such as deposits, deposits, and foreign matters on the roll surface, a longitudinal stretching process (hereinafter referred to as a roll stretching process) , "MD process") and a method of installing a roll cleaner at the preheating inlet and the cooling roll.

  In addition, there is a method in which the degree of cleanliness in the laminated film manufacturing process is class 1000 or less (1000 particles or less of 0.5 μm or more in a volume per cubic foot). It is preferable to use clean air of class 100 or less for the air cooling device for cooling the anti-roll surface.

  Further, there is a method of cleaning the roll by an operation of scraping a defect on the roll using an abrasive before manufacturing the laminated film. In addition, in order to prevent the film from adsorbing dust or the like due to the generation of static electricity and causing a defect, there is a method of providing a static eliminator so that the charge amount of the film becomes ± 1500 V or less in all steps. The process from the casting of the base film to the tenter described later is a process in which scratches are mainly likely to occur, and laying out this section in a compact manner and reducing the passage time to 5 minutes or less can also contribute to the suppression of the occurrence of defects. .

  About a roll, it can be set as the structure where the fault of a roll surface does not contact a film directly by forming a water film on the roll surface, or setting it as an air floating type roll. Moreover, the adhesion of the defect to a roll surface can be reduced and the defect of a roll surface can be reduced because the oligomer amount which precipitates from a film shall be 1000 ppm or less.

  Furthermore, in the winding step after stretching described later, the surface on the end side in the width direction of the film (lateral direction: the direction perpendicular to the running direction during the production of the laminated film) is pressed with a roller with a protrusion, and the portion And forming the projection on the roller with the projection into a tapered shape, and forming the projection on the roller with the projection. By rounding the top and setting the curvature radius of the top surface to 0.4 mm or less, it is possible to prevent the film and the defect from contacting each other in the film winding apparatus.

  Moreover, as a method for preventing the film from shifting on the roll surface, for example, the following methods can be employed.

  By increasing the adhesion of the film to the roll by reducing the diameter of the roll, using a suction roll, electrostatic adhesion, or using a part nip adhesion device, the occurrence of long scratches can be suppressed. In particular, reducing the diameter of the roll also subdivides the amount of shift of the film and can contribute to the prevention of long scratches. In addition, many of the scratches increase in length and frequency toward the end in the roll width direction, and it is difficult to obtain a scratch-free portion at the end in the roll width direction. By trimming around the center of the direction, a film with few scratches can be obtained.

  As a cause of occurrence of longitudinal scratches or lateral scratches, deformations such as expansion and contraction in the longitudinal direction or the lateral direction of the film can be mentioned, respectively. These film deformations are mainly caused by temperature changes in the film. Therefore, for example, by suppressing the temperature change of the film on the roll surface, the amount of film deformation due to such temperature can be reduced, and the occurrence of vertical scratches and horizontal scratches can be prevented. Specifically, the temperature change of the film per roll is 40 ° C. or less, preferably 30 ° C. or less, more preferably 20 ° C. or less, still more preferably 10 ° C. or less, and particularly preferably 5 ° C. or less. Is recommended.

  Examples of the method for suppressing the temperature change of the film on the roll surface include air cooling between the rolls and water cooling through a water tank. Furthermore, the temperature change of the film on the roll surface per roll can be reduced by increasing the number of rolls. Preferably, the number of rolls in the MD process is 10 or more.

  Further, by setting the relationship between the relative speeds of the plurality of rolls to a speed profile that is closest to the amount of deformation due to the temperature and tension of the film, it is possible to reduce the vertical shift of the film.

  Furthermore, in the coating step of the coating liquid for forming the adhesive property-modified resin layer, which will be described later, the drying condition is completed at the beginning of the dryer section and is cooled to the outlet, whereby the film temperature at the outlet of the dryer is 40 ° C. In the following, film shift due to temperature change can be reduced.

  If the tension during running of the film is too low, the gripping force will be reduced and deviation will occur, and if it is too high, stress deformation will increase and deviation will occur, so the optimum tension range will be 4.9-29.4 MPa. It is preferable to adjust by the driving roll speed and tension adjusting means. Moreover, the shift | offset | difference of the film on a roll surface can be suppressed by making the friction coefficient between the film and roll in the use temperature at the time of manufacture 0.2 or more.

  Furthermore, it is preferable to use a special bearing for the free roll and to set the rotational resistance to 19.6 N or less. For the drive roll, the rotation spots are controlled to 0.01% or less.

  In the film after uniaxial stretching, stress is applied in the longitudinal direction in order to convey the film, and further, deformation stress commensurate with the Poisson's ratio and the elastic modulus is generated in the orthogonal direction. In order to reduce this stress and to reduce the heat shrinkage stress of the film, it is preferable to lower the orientation within a range that does not adversely affect the physical properties of the film. Specifically, the refractive index difference in the X-axis direction [(refractive index in the X-axis direction of uniaxially stretched film) − (refractive index in the X-axis direction of unstretched film)] is 0.01 to 0.12. A uniaxially oriented film with orientation is recommended.

An easy-adhesion layer is applied and laminated on at least one surface of the polyester film during or after this process in order to obtain sufficient adhesion to the near-infrared absorbing layer and the hard coat layer.

  The easy-adhesion layer can be applied by any known method. Examples include reverse roll coating method, gravure coating method, kiss coating method, roll brush method, spray coating method, air knife coating method, wire barber coating method, pipe doctor method, impregnation / coating method and curtain coating method. These methods can be performed alone or in combination.

The step of applying the coating solution may be a normal coating step, that is, a step of applying to a base film that has been biaxially stretched and heat-fixed, but is preferably applied during the manufacturing process of the film. More preferably, it is applied to the base film before crystal orientation is completed. The solid content concentration in the aqueous solution is usually 30% by weight or less, preferably 10% by weight or less. The aqueous coating solution is applied so that 0.01 to 5 g, preferably 0.2 to 4 g, is attached per 1 m ² of the running film. The film coated with the aqueous coating solution is guided to a tenter for stretching and heat setting, and heated there to form a stable film by a thermal crosslinking reaction, and becomes a polyester-based film. In order to obtain sufficient adhesion to the near-infrared absorbing layer or hard coat layer, the coating amount at this time is 0.01 g / m ² or more per 1 m ^{2 of} film, and heat treatment at 100 ° C. for 1 minute or more is performed. is necessary. The degree of cleanliness when applying the coating solution is preferably class 1000 or less in order to reduce adhesion of dust.

  As described above, an easy adhesion layer is laminated on the ultraviolet absorbing polyester film for plasma display of the present invention.

Examples of the resin for the easy-adhesion layer include copolymer polyester resins, polyurethane resins, acrylic resins, styrene-maleic acid graft polyester resins, acrylic graft polyester resins, and the like. At least one or more may be used. preferable. Among them, a resin composed of a copolyester resin and a polyurethane resin, and a styrene-maleic acid graft polyester resin are particularly preferable because of excellent adhesiveness. An example of a coating solution made of polyurethane resin will be described.

  The copolymerized polyester resin used in the easy-adhesion layer of the present invention has a branched glycol component as a constituent component.

  Examples of the branched glycol component mentioned here include 2,2-dimethyl-1,3-propanediol, 2-methyl-2-ethyl-1,3-propanediol, and 2-methyl-2-butyl-1,3. -Propanediol, 2-methyl-2-propyl-1,3-propanediol, 2-methyl-2-isopropyl-1,3-propanediol, 2-methyl-2-n-hexyl-1,3-propanediol 2,2-diethyl-1,3-propanediol, 2-ethyl-2-n-butyl-1,3-propanediol, 2-ethyl-2-n-hexyl-1,3-propanediol, 2, 2-di-n-butyl-1,3-propanediol, 2-n-butyl-2-propyl-1,3-propanediol, and 2,2-di-n-hexyl-1,3-propanediol Etc., and the like.

  The branched glycol component is contained in the total glycol component in a proportion of preferably 10 mol% or more, more preferably 20 mol% or more. As the glycol component other than the above compounds, ethylene glycol is most preferable. If it is a small amount, diethylene glycol, propylene glycol, butanediol, hexanediol, 1,4 cyclohexanedimethanol or the like may be used.

  As the dicarboxylic acid component contained as a constituent component in the copolymer polyester resin, terephthalic acid and isophthalic acid are most preferable. If the amount is small, other dicarboxylic acids; diphenylcarboxylic acid and 2,6-naltalenedicarboxylic acid aromatic dicarboxylic acid may be added and copolymerized.

  In addition to the dicarboxylic acid component, 5-sodium sulfoisophthalic acid is preferably used in the range of 1 to 10 mol% in order to impart water dispersibility. For example, sulfoterephthalic acid, 5-sulfoisophthalic acid, 4- Examples thereof include sulfonaphthalene isophthalic acid-2,7-dicarboxylic acid and 5- (4-sulfophenoxy) isophthalic acid and salts thereof.

  The polyurethane resin used for the easy-adhesion layer of the present invention is, for example, a resin containing a block type isocyanate group, in which a terminal isocyanate group is blocked with a hydrophilic group (hereinafter referred to as a block), a heat-reactive water-soluble urethane, etc. Is mentioned. Examples of the isocyanate group blocking agent include bisulfites and sulfonic acid group-containing phenols, alcohols, lactam oximes and active methylene compounds. The blocked isocyanate group makes the urethane prepolymer hydrophilic or water-soluble. When heat energy is applied to the resin during drying or heat setting during film production, the blocking agent is released from the isocyanate group, so the resin fixes a water-dispersible copolyester resin mixed in a self-crosslinked stitch. And reacts with the terminal groups of the resin. The resin under preparation of the coating solution is hydrophilic and has poor water resistance, but when the thermal reaction is completed by coating, drying and heat setting, the hydrophilic group of the urethane resin, that is, the blocking agent is released, so the water resistance is good. A coating film is obtained.

  Among the above blocking agents, bisulfites are most preferred as those that are suitable for heat treatment and heat treatment and are widely used industrially.

  The chemical composition of the urethane prepolymer used in the above resin is (1) an organic polyisocyanate having two or more active hydrogen atoms in the molecule, or a molecular weight having at least two active hydrogen atoms in the molecule. 200 to 20,000 compounds, (2) an organic polyisocyanate having two or more isocyanate groups in the molecule, or (3) a chain extender having at least two active hydrogen atoms in the molecule. The resulting compound has a terminal isocyanate group.

  The compound (1) generally known is a compound containing two or more hydroxyl groups, carboxyl groups, amino groups or mercapto groups in the terminal or molecule, and particularly preferred compounds include polyether polyols. And polyether ester polyols.

  Examples of polyether polyols are compounds obtained by polymerizing alkylene oxides such as ethylene oxide and propylene oxide, styrene oxide and epichlorohydrin, or the like, or random polymerization, block polymerization, or addition polymerization to a polyhydric alcohol. There are compounds. Examples of the polyester polyol and the polyether ester polyol mainly include linear or branched compounds. Polyvalent saturated or unsaturated carboxylic acids such as succinic acid, adipic acid, phthalic acid and maleic anhydride, or the carboxylic acid anhydride, ethylene glycol, diethylene glycol, 1,4-butanediol, neopentyl glycol, 1 Condensation with polyvalent saturated and unsaturated alcohols such as 1,6-hexanediol and trimethylolpropane, polyalkylene ether glycols such as relatively low molecular weight polyethylene glycols and polypropylene glycols, or mixtures of these alcohols Can be obtained.

  Further, polyesters obtained from lactones and hydroxy acids can be used as the polyester polyol, and polyether esters obtained by adding ethylene oxide or propylene oxide to a pre-manufactured polyester can also be used. Examples of the organic polyisocyanate (2) include isomers of toluylene diisocyanate, aromatic diisocyanates such as 4,4-diphenylmethane diisocyanate, aromatic aliphatic diisocyanates such as xylylene diisocyanate, isophorone diisocyanate and 4,4. -Alicyclic diisocyanates such as dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, and aliphatic diisocyanates such as 2,2,4-trimethylhexamethylene diisocyanate, or a single or a plurality of these compounds with trimethylolpropane and the like in advance. Examples include added polyisocyanates.

  Examples of the chain extender having at least two active hydrogens in (3) above include glycols such as ethylene glycol, diethylene glycol, 1,4-butanediol, and 1,6-hexanediol, glycerin, trimethylolpropane, and Examples include polyhydric alcohols such as pentaerythritol, diamines such as ethylenediamine, hexamethylenediamine, and piperazine, amino alcohols such as monoethanolamine and diethanolamine, thiodiglycols such as thiodiethylene glycol, and water. In order to synthesize the urethane polymer of the above (3), it is usually 5 minutes to several times at a temperature of 150 ° C. or less, preferably 70 to 120 ° C., by a single-stage or multi-stage isocyanate polyaddition method using the chain extender. Let react for hours. The ratio of isocyanate groups to active hydrogen atoms can be freely selected as long as it is 1 or more, but it is necessary that free isocyanate groups remain in the obtained urethane prepolymer.

  Further, the content of free isocyanate groups may be 10% by weight or less, but in view of the stability of the urethane polymer aqueous solution after being blocked, it is preferably 7% by weight or less.

  The urethane prepolymer obtained is preferably blocked using bisulfite. Mix with aqueous bisulfite solution and allow reaction to proceed with good agitation for about 5 minutes to 1 hour. The reaction temperature is preferably 60 ° C. or lower. Thereafter, it is diluted with water to an appropriate concentration to obtain a heat-reactive water-soluble urethane composition. When the composition is used, it is prepared to have an appropriate concentration and viscosity. However, when heated to about 80 to 200 ° C., the bisulfite of the blocking agent is dissociated and the active isocyanate group is regenerated, so that the prepolymer A polyurethane polymer is produced by a polyaddition reaction that occurs within or between the molecules of the polymer, and has the property of causing addition to other functional groups.

  As an example of the resin (B) containing a block-type isocyanate group described above, a trade name Elastron manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd. is typically exemplified. Elastolone is a compound in which an isocyanate group is blocked with sodium bisulfite, and is water-soluble due to the presence of a carbamoylsulfonate group having strong hydrophilicity at the molecular end.

  When the coating liquid is prepared by mixing the copolymerized polyester resin (A) containing a branched glycol component and the resin (B) containing a block type isocyanate group used in the present invention, the resin (A) and the resin The weight ratio of (B) is preferably (A) :( B) = 90: 10 to 10:90, more preferably (A) :( B) = 80: 20 to 20:80. If the ratio of the said resin (A) with respect to solid content weight is less than 10%, the applicability | paintability to a base film is unsuitable, and the adhesiveness between a surface layer and this film will become inadequate.

When it is less than 10%, practical adhesiveness cannot be obtained in a UV curing type hard coat.
In order to promote the thermal crosslinking reaction, a catalyst may be added to the aqueous coating solution used in the present invention, such as various inorganic substances, salts, organic substances, alkaline substances, acidic substances and metal-containing organic compounds. These chemicals are used. Moreover, in order to adjust pH of aqueous solution, you may add an alkaline substance or an acidic substance.

  When applying the aqueous coating solution to the surface of the base film, a known anionic surfactant and nonionic surfactant are required to increase the wettability of the film and coat the coating solution uniformly. An amount can be added and used. As the solvent used in the coating solution, alcohols such as ethanol, isopropyl alcohol and benzyl alcohol may be mixed in addition to water until the ratio of the total coating solution is less than 50% by weight. Furthermore, if it is less than 10 weight%, you may mix in the range which can melt | dissolve organic solvents other than alcohol. However, the total of alcohols and other organic solvents in the coating solution is less than 50% by weight.

  If the addition amount of the organic solvent is less than 50% by weight, the drying property is improved at the time of coating and drying, and the appearance of the coating film is improved as compared with the case of using only water. If it exceeds 50% by weight, the evaporation rate of the solvent is fast, the coating solution concentration changes during coating, the viscosity rises and the coating property decreases, and there is a risk of causing poor appearance of the coating film, Furthermore, there is a risk of fire.

  The solution viscosity of the coating solution is preferably 1.0 PaS (Pascal Sec) or less. When the pressure is 1.0 PaS (Pascal Sec) or higher, streaky coating thickness spots are likely to occur.

  In the present invention, since a lubricant intended to impart easy lubricity is not added to the base film, it is preferable to add particles to the aqueous coating solution to form appropriate protrusions on the film surface. Examples of such particles include calcium carbonate, calcium phosphate, silica, kaolin, talc, titanium dioxide, alumina, barium sulfate, calcium fluoride, lithium fluoride, zeolite, molybdenum sulfide and other inorganic particles, crosslinked polymer particles, oxalic acid There may be mentioned organic particles such as calcium. Of these, silica is most preferable because it has a relatively close refractive index to that of the polyester resin and can easily provide high transparency.

  The average particle diameter of the particles added to the aqueous coating solution is usually 1.0 μm or less, preferably 0.5 μm or less, more preferably 0.1 μm or less. When the average particle diameter exceeds 1.0 μm, the film surface becomes rough and the transparency of the film tends to be lowered. The particle content contained in the coating solution is usually such that the particle content of the coating film after application and drying is 60% by weight or less, preferably 50% by weight or less, more preferably 40% by weight or less. Added. If the particle content of the coating film exceeds 60% by weight, the easy adhesion of the film may be impaired.

  Two or more kinds of the above particles may be blended in the film, or the same kind of particles having different particle diameters may be blended. In any case, it is preferable that the average particle diameter of the whole particle and the total content satisfy the above-mentioned range. When applying the coating solution, it is necessary to dispose a filter medium so that the coating solution is precisely filtered just before coating in order to remove coarse aggregates of particles in the coating solution.

  The filter medium for microfiltration of the coating solution used in the present invention needs to have a filtration particle size of 25 μm or less (initial filtration efficiency 95%). When the particle size is 25 μm or more, the coarse agglomerates cannot be removed sufficiently, and many coarse agglomerates that cannot be removed are 100 μm or more because the coarse agglomerates of particles spread in the easy-adhesion layer when applied, dried and uniaxially or biaxially stretched As a result, many optical defects are generated.

  The type of filter medium for microfiltration of the coating solution is not particularly limited as long as it has the above performance, and examples thereof include a filament type, a felt type, and a mesh type.

  The material of the filter medium for finely filtering the coating solution has the above-mentioned performance and is not particularly limited as long as it does not adversely affect the coating solution. Examples thereof include stainless steel, polyethylene, polypropylene, and nylon.

  Various additives such as an antistatic agent, a pigment, an organic filler, and a lubricant may be mixed in the composition of the aqueous coating solution as long as the effect is not lost. Furthermore, since the coating solution is aqueous, other water-soluble resins, water-dispersible resins, emulsions, and the like may be added to the coating solution in order to improve performance as long as the contribution effect is not lost.

The near-infrared absorption layer used in the present invention is not particularly limited as long as it has a performance capable of sufficiently absorbing the near-infrared region as emitted from a plasma display or the like, but for example, described in JP-A-2002-226827 And a method using a near infrared absorbing dye.

  That is, a near-infrared absorbing compound precursor (neutral molecular compound) represented by the following structural formula (3) is synthesized by a literature method (Shigeru Sasaki and Masahichi Iyoda, Chemistry Letters, 1995).

(In the formula, -O-n-Bu is an abbreviation for n-butoxy group.) Next, the precursor (1 part) is dissolved in acetone (20 parts), and further doubled with respect to the precursor. An amount of silver hexafluoroantimonate was added. After stirring at room temperature for 2 hours, the precipitated silver is filtered off, the filtrate is diluted with ether, and the precipitated solid is collected by filtration and washed with ether and hexane to give the following structural formula (4). The indicated near infrared absorbing compound (4) (0.5 parts) was obtained.

(In the formula, -O-n-Bu is an abbreviation for n-butoxy group.)
The near-infrared absorbing compound was dissolved in methylene chloride to prepare a 10 mg / L solution. The prepared solution was put into a quartz cell having a cell width of 1 cm, and the transmittance was measured with a spectrophotometer. The near-infrared absorbing compound has an absorption peak wavelength in the range of 882 nm ± 30 nm, and as shown in Table 1, the absorption in the near-infrared region at the wavelength 882 nm is large and the visible light region is transmitted at 550 nm. The result is that the rate is high.

  In the production of the near-infrared absorbing filter, the method for laminating the near-infrared absorbing layer on the base material is not particularly limited, but the coating method is preferable in terms of thickness uniformity and cost.

  In the case of the coating method, coating is performed by dissolving these in a solvent capable of dissolving the near-infrared absorbing compound and the polymer resin. As the solvent at this time, for example, acetone, ethyl methyl ketone, isobutyl methyl ketone, ethyl acetate, propyl acetate, methanol, ethanol, isopropyl alcohol, ethyl cellosolve, butyl cellosolve, benzene, toluene, xylene, tetrahydrofuran, n-hexane, n -A heptane, a methylene chloride, chloroform, N, N- dimethylformamide, water etc. are mentioned, You may use together 1 or 2 or more, It is not limited to these.

  The coating method will be described in detail. A gravure coating method and a reverse coating method in which a polymer resin and at least one near-infrared absorbing compound are added and dissolved in the above-mentioned solvent, and this can be coated on a substrate at a high speed, for example. , Kiss roll coating method, roll coating method and the like can be applied, and the method is excellent in workability and productivity. The near-infrared absorbing compound in the near-infrared absorbing layer is preferably in a state dissolved in a polymer resin.

  The near-infrared absorbing filter having a configuration in which a near-infrared absorbing layer is laminated only on one side of an ultraviolet-absorbing polyester film substrate for plasma display according to the present invention is, for example, the first-layer near-infrared absorption by the above method on the substrate. After providing a layer, it can obtain by providing the near-infrared absorption layer after the 2nd layer by the coating method etc. further. The solvent, binder and method used to form the first and second and subsequent near-infrared absorbing layers may be the same or different. When providing the near-infrared absorption layer after the 2nd layer by a coating method, in order to avoid mixing of a layer, it is preferable to provide the 1st near-infrared absorption layer after drying.

  The near infrared absorbing layer may further contain various conventional additives. Examples of the additive include an antistatic agent and a stabilizer. From the viewpoint of transparency, it is preferable that the additive does not substantially contain inert particles for the purpose of imparting slipperiness.

The filter for plasma display panels of this invention It can be used for the use which interrupts the unnecessary near infrared rays radiated | emitted from a plasma display, and has the outstanding durability.

  The ultraviolet absorbing polyester film for plasma display of the present invention and the method for producing a filter for plasma display panel using the same will be described with reference to the case where polyethylene terephthalate (hereinafter abbreviated as PET) is used as a base material. Of course, it is not limited to these.

Further, “parts” in Examples and Comparative Examples means “parts by weight” unless otherwise specified, and the spectroscopic characteristics described in this specification are those of a self-recording spectrophotometer (Hitachi U-3500 type). The measured wavelength is in the range of 200-1500 nm.
Evaluation method (1) Absorption coefficient
Absorbance at a predetermined wavelength was measured using U-2001 Hitachi Double Beam Spectrophotometer.
(2) Adhesiveness when a photocurable acrylic hard coat layer is provided on the adhesive layer (adH1 and adH2)
A hard coat agent (Seika Beam EXF01 (B)) manufactured by Dainichi Seika Co., Ltd. was applied to the surface of the easy-adhesion layer of the UV-absorbing polyester film for plasma display obtained in Examples and Comparative Examples using a # 8 wire bar. After drying for a minute and removing the solvent, a hard coat layer of 2 μm was formed under conditions of 80 w / cm with a high-pressure mercury lamp, an irradiation distance of 15 cm, and 5 m / min. Adhesiveness was calculated | required with the test method according to 8.5.1 description of JIS-K5400 (adH1). Specifically, 100 grid-like cuts that penetrate the easy-adhesion layer and reach the base film are attached using a cutter guide with a gap interval of 2 mm, and cellophane adhesive tape (Nichiban 405 No. 24 mm width) is used. Then, the film was rubbed with an eraser and completely adhered to the cut surface, and then peeled off vertically to visually determine the adhesion from the following formula.

adH (%) = (1-peeling area / evaluation area) × 100
Moreover, after irradiating the film in which the obtained hard-coat layer was formed from the hard-coat surface side using a sunshine weather meter for 500 hours, it was adhesiveness by the test method according to 8.5.1 description of JIS-K5400. (AdH2).
(3) Adhesion when a near-infrared absorbing layer is provided on the easy-adhesion layer (adNIR)
The coating liquid shown below (Table 1) was coated on one side with a gravure roll on the surface of the UV-adhesive polyester film for plasma display obtained in Examples and Comparative Examples, and hot air at 150 ° C. was applied to the surface of the film. It was dried for 1 minute while feeding at 5 m / sec. The thickness of the coating layer (near infrared absorption layer) after drying was 8.0 μm. Adhesiveness was calculated | required with the test method according to 8.5.1 description of JIS-K5400. Specifically, 100 grid-like cuts that penetrate the easy-adhesion layer and reach the base film are attached using a cutter guide with a gap interval of 2 mm, and cellophane adhesive tape (Nichiban 405 No. 24 mm width) is used. Then, the film was rubbed with an eraser and completely adhered to the cut surface, and then peeled off vertically to visually determine the adhesion from the following formula.

  adNIR (%) = (1-peeling area / evaluation area) × 100

Coating solution for near-infrared absorbing layer

    X: The IR spectrum (I) of the surface layer of a blank sample (polyethylene terephthalate (PET) film containing no UV absorber) and the IR layer spectrum (II) of the sample of the present invention are measured.

Taking the difference spectrum of (I) and (II), the absorbance at 1700-1800 cm ⁻¹ (characteristic absorption of the UV absorber) and the absorption at 1505 cm ⁻¹ obtained from the IR spectrum of (II) (PET X) was obtained by taking the absorbance ratio (1700 to 1800 cm ⁻¹ / 1505 cm ⁻¹ ).

    Y: 50% of the total thickness of the sample of the present invention was shaved off in the thickness direction, and the exposed surface (film central portion) was measured to make (II). Asked.

FT-IR device: Digilab FTS-7000e
Single reflection ATR device: Thunderdome by Thermo Spectra-Tech
IRE: Ge, Incident angle: 45 °
Resolution: 8cm-1
Number of integrations: 128 times (5) Detection and measurement of foreign matter and scratches Detection of scratches Optical defects that are optically recognized as having a size of 50 μm or more for 16 pieces of 250 mm × 250 mm film pieces by the following optical defect detection method. Is detected. Note that the film to be measured is 24 hours after the start of film formation.
5.1 [Optical defect detection method]
A fluorescent lamp of 20 W × 2 lamps is arranged as a projector at 400 mm below the XY table, and a test piece to be measured is placed on a mask having a slit width of 10 mm provided on the XY table. When light is incident so that the angle formed between the line connecting the projector and the light receiver and the vertical direction of the surface of the test piece is 12 °, if there is a scratch on the test piece at the incident position, that part shines. The amount of light in that portion is converted into an electrical signal by a CCD image sensor camera placed 500 mm above the XY table, the electrical signal is amplified, differentiated, and compared with a threshold (threshold) level and a comparator, resulting in an optical defect. The detection signal is output. Also, using a CCD image sensor camera, a scratch image is input, the video signal of the input image is analyzed by a predetermined procedure, the size of the optical defect is measured, and the position of the defect of 50 μm or more is displayed. To do. Optical defects are detected on both sides of the test piece.
5.2 Measurement of scratch size on film surface From the optical defect portion detected in (5.1) above, defects due to scratches are selected. The above-mentioned test piece is cut into an appropriate size, and is observed from a direction perpendicular to the surface of the test piece using a three-dimensional shape measuring device TYPE550 manufactured by Micromap, and the size of the scratch is measured. When observed from the direction perpendicular to the surface of the test piece, that is, the film surface, the concavities and convexities of the flaws that are close to each other within 50 μm are regarded as the same flaws, and the length and width of the rectangle with the smallest area covering the outermost part of those flaws are determined. The length and width of the scratch. Then, the scratch whose longitudinal direction is ± 45 ° or less from the vertical direction (traveling direction in the production of the optical laminated film) is defined as a vertical scratch, and ± 45 from the horizontal direction (orthogonal direction of the vertical direction). Measure the depth (difference between the highest and lowest flaws) and length, with the flaw less than ° as the horizontal flaw. From this result, the number of vertical scratches, horizontal scratches, and total scratches (pieces / m ² ) having a depth of 1 μm or more and a length of 3 mm or more is obtained.

× a case 100 more than / m ^2, a 100 to 51 pieces / ^{m 2} △, a 50-31 amino / m ² ○, was 30 / m ² or less ◎.
5.3 Measuring method of size of foreign matter in film and surface-attached foreign matter From the defective portion detected by the optical defect detecting device described above, an optical defect due to the foreign matter and an optical defect due to coarse aggregates of particles in the coating solution were selected. Furthermore, it cut out to a suitable magnitude | size and measured the magnitude | size when observing from a perpendicular direction with respect to a film surface with the microscope with a scale. In the case of an optical defect due to a foreign material, the number of foreign materials having a maximum diameter of 20 μm or more (pieces / m ² ) was obtained. In the case of coarse aggregates of particles in the coating solution, the number of foreign matters (pieces / m ² ) having a maximum diameter of 100 μm or more was determined.
Measurement of height and depth of unevenness on film surface Measured using a non-contact type three-dimensional roughness meter (550 by Micromap). Using the optical defect detection device described above, optical defects due to foreign matters and optical defects due to coarse aggregates of particles in the coating solution were selected from the detected defect portions. Further cut out to an appropriate size, perform Al vapor deposition, and measure the size, height and depth when observed from the direction perpendicular to the film surface with a non-contact type three-dimensional roughness meter (550 by Micromap). It was measured. In the case of an optical defect due to foreign matter, the number of foreign matters (pieces / m ² ) having a maximum diameter of 20 μm or more was determined.
The case of more than 10 pieces / m ² was evaluated as x, 10-6 pieces / m ² as Δ, 5-3 pieces / m ² as ○, and 2 pieces / m ² or less as ◎.
(6) Outermost layer thickness (μm) of laminated film
Several levels of polyester having a known particle content (such as silica) are prepared in advance. Only the outermost layer of the film contains particles, and the intermediate layer does not contain particles.
Using SIMS (secondary ion mass spectrometer), the concentration ratio (X / Y) between the element (X) due to the particles and the carbon element (Y) of the polyester is determined.
By measuring X / Y in the depth direction of the film from the polyester surface layer on the outermost layer side, the concentration of particles can be known.
The M / C measured in this way shows a high value on the film surface layer, but rapidly decreases as it approaches the main layer (inflection point A), and then stabilizes at a constant value (inflection point B). A and B are connected by a straight line, and the distance from the half value to the outermost layer is defined as the lamination thickness.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited by the following examples, but may be appropriately modified within a range that can meet the purpose described above and below. It is also possible to carry out and they are all included in the technical scope of the present invention.
Example 1
(1) Production of Masterbatch (A) Dried UV absorber CYASORB UV-3638 manufactured by Siatec Co., Ltd. (2,2 ′-(1,4-phenylene) bis (4H-3,1-benzoxazinone-4- ON)) 10 parts by weight and 90 parts by weight of PET resin (ME-553 manufactured by Toyobo Co., Ltd.) containing no particles were mixed, and a master batch was prepared using a kneading extruder. The extrusion temperature at this time was 285 ° C., and the extrusion time was 7 minutes.
(Adjustment of the coating liquid (A) for forming the easy adhesion layer)
A coating solution A for forming an easy-adhesion layer was prepared according to the following method. 95 parts of dimethyl terephthalate, 95 parts of dimethyl isophthalate, 35 parts of ethylene glycol, 145 parts of neopentyl glycol, 0.1 part of zinc acetate and 0.1 part of antimony trioxide are charged into a reaction vessel, and the ester is added at 180 ° C. for 3 hours. An exchange reaction was performed. Next, 6.0 parts of 5-sodium isophthalic acid was added and an esterification reaction was performed at 240 ° C. over 1 hour, followed by a polycondensation reaction to obtain a polyester resin.

6.7 parts of a 30% aqueous dispersion of the obtained polyester resin, 20% aqueous solution of a self-crosslinking polyurethane resin containing an isocyanate group blocked with sodium bisulfite (Daiichi Kogyo Seiyaku: trade name Elastron H-3) ), 40 parts of elastolone catalyst (Cat 64), 47.8 parts of water and 5 parts of isopropyl alcohol, 1% by weight of anionic surfactant and lubricant (Nissan Chemical Industries) A coating solution A was prepared by adding 5% by weight of Snowtex OL).
(2) Formation of UV-absorbing polyester film for plasma display 90 parts by weight of a pellet (ME-553 manufactured by Toyobo Co., Ltd.) containing no PET resin particles having an intrinsic viscosity of 0.62 dl / g as an intermediate layer raw material and a master batch (A) 10 parts was dried under reduced pressure (1 Torr) at 135 ° C. for 6 hours, and then supplied to the extruder 2 (for the intermediate layer B layer). Polyethylene terephthalate pellets (ME-553 manufactured by Toyobo Co., Ltd.) containing no particles were dried under reduced pressure (1 Torr) at 135 ° C. for 6 hours, and then supplied to the extruder 1 (for outer layer A layer and outer layer C layer). The resin temperature up to the melter, kneading section, polymer tube, gear pump, and filter of the extruder was 280 ° C, and then 275 ° C for the polymer tube, and was laminated in a 3 layer merge block and extruded into a sheet from the die. . Each of these polymers was filtered using a stainless steel sintered filter medium (nominal filtration accuracy: 10 μm particles, 95% cut). The resin temperature of the flat die was 275 ° C. The extruded resin was wound around a casting drum (roll diameter: 400φ, Ra: 0.1 μm or less) having a surface temperature of 30 ° C. using an electrostatic application casting method, and cooled and solidified to produce an unstretched film. The discharge rate at this time was 48 kg / hr, and the obtained unstretched sheet had a width of 300 mm and a thickness of 1400 μm.

  Moreover, the discharge amount of each extruder was adjusted so that the ratio of the thickness of the outermost layer (A layer and C layer) was 10% with respect to the total thickness.

  Next, the cast film is heated to 100 ° C. using a heated roll group and an infrared heater, and then stretched 3.5 times in the longitudinal direction (running direction) with a roll group having a difference in peripheral speed, and a uniaxially oriented film Got.

  In addition, regarding all the rolls used at the time of film manufacture, the surface roughness of the roll was controlled to 0.1 μm or less by Ra, and roll cleaners were installed at the preheating inlet and the cooling roll in the longitudinal stretching process. The roll diameter in the longitudinal stretching step was 150 mm, and the film was brought into close contact with the roll using a suction roll, electrostatic contact, and part nip contact apparatus.

Thereafter, the coating liquid A for forming an easy-adhesion layer was microfiltered with a felt type polypropylene filter medium having a filtration particle size (initial filtration efficiency of 95%) of 25 μm, applied to both sides by a reverse roll method, and dried. After coating, the end of the film is gripped with a clip, guided to a hot air zone heated to 130 ° C., dried, stretched 4.0 times in the width direction, and heat treated at 230 ° C. for 5 seconds. Among them, a relaxation treatment of 3% in the width direction was performed as necessary to obtain an ultraviolet-absorbing polyester film for plasma display. The film thickness at this time was 100 μm, and the coating amount of the easy adhesion layer at this time was 0.01 g / m ² .
(Example 2)
In Example 1, the plasma display was made in the same manner except that the discharge amount of each extruder was adjusted so that the thickness ratio of the outermost layer (A layer and C layer) on one side was 5% with respect to the total thickness. An ultraviolet absorbing polyester film was obtained.
(Example 3)
An ultraviolet-absorbing polyester film for plasma display was obtained in the same manner as in Example 2 except that the temperature of the polymer tube and flat die after the filter was set so that the resin temperature was 285 ° C.
(Reference Example 1)
In Example 1, the plasma display was made in the same manner except that the discharge amount of each extruder was adjusted so that the thickness ratio of the outermost layer (A layer and C layer) on one side was 3% with respect to the total thickness. An ultraviolet absorbing polyester film was obtained.
( Reference Example 2 )
In Example 1, 20 parts by weight of a polymer ultraviolet absorber (NOVAPEX U-110 (manufactured by Mitsubishi Chemical Corporation)) is added to polyethylene terephthalate pellets (ME-553 manufactured by Toyobo Co., Ltd.) containing no particles in the outermost layer. A UV-absorbing polyester film for plasma display was obtained in the same manner except that it was added to the extruder 1 and supplied to the extruder 1 (for the outer layer A layer and for the outer layer C layer).
(Comparative Example 1)
In Example 1, the plasma display was performed in the same manner except that the discharge amount of each extruder was adjusted so that the thickness ratio of the outermost layer (A layer and C layer) on one side was 1% with respect to the total thickness. An ultraviolet absorbing polyester film was obtained.
(Comparative Example 2)
A UV-absorbing polyester film for plasma display was obtained in the same manner as in Example 1 except that the outermost layer was not provided outside the resin constituting the intermediate layer.
(Comparative Example 3)
In Example 1, the plasma display was made in the same manner except that the discharge amount of each extruder was adjusted so that the thickness ratio of the outermost layer (A layer and C layer) on one side was 30% with respect to the total thickness. An ultraviolet absorbing polyester film was obtained.

Absorption coefficient of Examples 1 to 3, Reference Examples 1 to 2 and Comparative Examples 1 to 3, adhesiveness, evaluation of scratches on film surface 24 hours after film formation start, evaluation of foreign matter adhered to film and surface layer, film surface layer and internal Table 2 shows the absorbance ratio.

Claims (9)

A filter for a plasma display panel in which a near-infrared absorbing layer is provided on at least one side of a polyester film substrate having an easy adhesion layer on both sides,
The polyester film base material is a biaxially oriented laminated polyester film base material having a laminated structure of three or more layers, and at least one UV absorbing member selected from the group consisting of a benzotriazole type and a cyclic imino ester type at least in the intermediate layer Containing the agent, the absorbance and adhesiveness of the polyester film substrate satisfy the following formula,
The polyester film substrate has a thickness of 50 μm or more and 300 μm or less,
A filter for a plasma display panel, wherein the thickness of one outermost layer of the polyester film substrate is in the range of 5 to 15% of the total thickness.
abs (≦ 380) ≧ 2
adH1 ≧ 90
adNIR ≧ 89
Where abs (≦ 380) is the absorbance at a wavelength of 380 nm or less,
adH1 is the adhesion when a photo-curing acrylic coating layer is provided on the easy-adhesion layer.
adNIR represents the adhesiveness when a near-infrared absorbing layer is provided on an easily adhesive layer. 2. The plasma display panel filter according to claim 1, wherein the polyester film substrate is substantially free of particles in all three layers. The filter for a plasma display panel according to claim 1 or 2, wherein the easy-adhesion layer comprises a copolyester resin and a polyurethane resin. The copolymerized polyester resin has a branched glycol component and 5-sodium sulfoisophthalic acid as constituent components,
The branched glycol component contains 10 mol% or more of the total glycol component,
The filter for a plasma display panel according to claim 3, wherein 5-sodium sulfoisophthalic acid is contained in an amount of 1 to 10 mol% in the total dicarboxylic acid component. 5. The plasma display according to claim 3, wherein a weight ratio of the copolyester resin and the polyurethane resin is copolyester resin: polyurethane resin = 90: 10 to 10:90. 6. Panel filter. The filter for a plasma display panel according to any one of claims 1 to 5, wherein the content of the ultraviolet absorber is 0.1 to 4% by weight based on the polyester. The plasma display panel filter according to any one of claims 1 to 6, wherein a decomposition start temperature of the ultraviolet absorbent is 290 ° C or higher. The ratio of the absorbance (X) of the polyester film substrate surface layer measured by FT-IR and the absorbance (Y) at the center of the film satisfies the following formula. Filter for plasma display panel.
0 ≦ X / Y ≦ 0.1
X: The IR spectrum (I) of the surface layer of a blank sample (polyethylene terephthalate (PET) film containing no UV absorber) and the IR layer spectrum (II) of the sample of the present invention are measured.
Taking the difference spectrum of (I) and (II), the absorbance at 1700-1800 cm ⁻¹ (characteristic absorption of the UV absorber) and the absorption at 1505 cm ⁻¹ obtained from the IR spectrum of (II) (PET X) was obtained by taking the absorbance ratio (1700 to 1800 cm ⁻¹ / 1505 cm ⁻¹ ).
Y: 50% of the total thickness of the sample of the present invention was shaved off in the thickness direction, and the exposed surface (film central portion) was measured to make (II). Asked. It is a polyester film base material used for the filter for plasma display panels in any one of Claims 1-8 ,
The polyester film substrate is manufactured through a process of supplying a raw material pet to an extruder and melt-extruding it into a sheet,
The extruder includes an extruder melt section, a kneading section, a first polymer pipe, a gear pump, a filter, a second polymer pipe, and a flat die,
The resin temperature up to the extruder melt part, kneading part, first polymer tube, gear pump, filter is 280-290 ° C, the second polymer tube, the resin temperature up to the flat die is 270-280 ° C,
The polyester film base material is a biaxially oriented laminated polyester film base material having a laminated structure of three or more layers, and at least one UV absorbing member selected from the group consisting of a benzotriazole type and a cyclic imino ester type at least in the intermediate layer Containing the agent, the absorbance and adhesiveness of the polyester film substrate satisfy the following formula,
The polyester film substrate has a thickness of 50 μm or more and 300 μm or less,
The polyester film substrate, wherein the thickness of one outermost layer of the polyester film substrate is in the range of 5 to 15% of the total thickness.
abs (≦ 380) ≧ 2
adH1 ≧ 90
adNIR ≧ 89
Where abs (≦ 380) is the absorbance at a wavelength of 380 nm or less,
adH1 is the adhesion when a photo-curing acrylic coating layer is provided on the easy-adhesion layer.
adNIR represents the adhesiveness when a near-infrared absorbing layer is provided on an easily adhesive layer.