JP4635434B2 - Polyester film for molding - Google Patents

Description

  The present invention relates to a film suitable for embossability. More specifically, it is suitable for use in the production of decorative boards with decorative properties by embossing for building materials, etc., and also has printability, transparency, rigidity, strength, form stability (heat shrinkage characteristics, uneven thickness), light resistance The present invention relates to an embossing film having excellent properties.

  Conventionally, as a sheet for processing, a polyvinyl chloride film is typical and has been preferably used in terms of workability. On the other hand, the film has problems such as generation of toxic gas when the film burns due to fire and the like, and problems such as bleed out of the plasticizer, and new materials have been demanded according to recent needs for environmental resistance.

  Polyester-based biaxially stretched films represented by polyethylene terephthalate are attracting attention because of their excellent environmental resistance and economic efficiency, but they do not meet market demand due to their poor embossability. . As a polyester film having improved embossability, a technique relating to a multilayer polyester stretched film composed of a copolymer polyester resin having a specific melting point is disclosed (for example, see Patent Document 1).

The above-mentioned multilayer stretched polyester film is improved with respect to the embossability at a temperature of about 150 ° C. as compared with a conventional homopolyester stretched film. However, the embossability in a low temperature region (for example, 120 to 130 ° C.) is not satisfied with a high market demand. Further, printability, transparency, rigidity, strength, form stability (heat shrinkage characteristics, thickness unevenness) and the like were not sufficient for market demand. Furthermore, since it has a multi-layer structure, it has a problem that it is inferior in economic efficiency, and it is strongly desired to solve these problems.
Japanese Patent Laid-Open No. 9-24588

  On the other hand, it has been attempted to develop a moldability improving technique having a flexibility that leads to an improvement in embossability using a copolyester resin. Conventionally, by using a copolymer polyester containing a long-chain linear aliphatic dicarboxylic acid component having 3 or more carbon atoms and / or a long-chain linear aliphatic glycol component as a film raw material, moldability is improved. Many techniques for improving have been disclosed. However, the polyester resin is softened by these copolymerization components, and it is inferior in rigidity, strength, and form stability (heat shrinkage characteristics, thickness unevenness, etc.) not only at the time of molding but also when actually used as a molded body. Has drawbacks. If the copolymer composition ratio of the above components is decreased in order to improve the form stability, the moldability is lowered, and it is difficult to achieve both moldability, strength and rigidity.

For example, a polyester film made of polyester containing neopentyl glycol as a copolymerization component is disclosed as the film made of the copolyester (see, for example, Patent Document 2 and Patent Document 3). Since the copolymer polyester films described in these conventional techniques have a thickness of 50 μm or less, film formation is relatively easy. However, when the thickness exceeds 50 μm, there is a tendency for the molecular orientation to be insufficiently controlled from the viewpoints of stress reduction and crystallinity at the time of stretching, which are inherently possessed by the copolyester, and form stability (Heat shrinkage characteristics, uneven thickness), rigidity and strength may be insufficient. Therefore, there has been a demand for a polyester film that is excellent in form stability (heat shrinkage characteristics, thickness unevenness), rigidity, and strength when using a molded body in a room temperature atmosphere while maintaining moldability.
JP-A-1-252658 Japanese Unexamined Patent Publication No. 1-445699

  Moreover, in order to improve the designability of a molded product, printing is often performed on the film surface before the film is molded. However, the prior art has a problem that the printability and the heat resistance stability of the printed layer are insufficient. Furthermore, since the printed layer is often applied to the back side of the film, it is desired that the transparency of the film is high from the viewpoint of print clarity. However, since the conventional molded film has low transparency, there is a problem that the printed appearance is deteriorated.

For such a problem, a biaxially oriented film of a copolyester has been proposed (see, for example, Patent Document 4). However, when trying to achieve flexibility, there is a problem that heat resistance is lowered. On the other hand, a film obtained by using a raw material obtained by copolymerizing polyethylene terephthalate alone or in a range in which the melting point does not decrease has been proposed (see, for example, Patent Document 5). When it tried to obtain, there was a tendency for the transparency of a film to fall. Thus, in the prior art, a film satisfying heat resistance, transparency, and flexibility has not been obtained so far.
Japanese Patent Laid-Open No. 3-67629 JP 2001-347565 A

  The object of the present invention is to eliminate the above-mentioned problems of the prior art, embossability, particularly low temperature embossability, rigidity, strength, form stability (heat shrinkage characteristics, thickness unevenness), printability, light resistance, etc. An object of the present invention is to provide an easily embossable film excellent in thickness.

That is, the present invention is a polyester film comprising a copolymer polyester composed of an aromatic dicarboxylic acid component, ethylene glycol, and a glycol component containing a branched aliphatic glycol and / or an alicyclic glycol, The film has a ratio (H / d) of haze H (%) to thickness d (μm) of 0.010 or less, and the film has a stress at 100% elongation in the longitudinal and width directions of 10 MPa or more at 25 ° C. a 1~100MPa at 180MPa and less than 100 ° C., further Ri na an easy printability improving layer provided in-line coating method comprising a polyester at least on one side, a polyester constituting the easy printability improving layer is an unsaturated group Containing dicarboxylic acid 0.5 to 15.0 mol% and dicarboxylic acid 85.0 to 9 containing no unsaturated group The two polyester copolymer water-insoluble obtained dicarboxylic acid component is reacted with a polyol component with .5 mole%, and wherein the resin der Rukoto grafted modified with an unsaturated bond-containing monomer it is a molded polyester film for you.

Since the polyester film for molding of the present invention controls the stress at 100% elongation in the longitudinal direction and width direction of the film independently at 25 ° C. and 100 ° C., it is embossed at low temperature and used as a molded product. Excellent shape stability (heat shrinkage characteristics, thickness irregularity), rigidity, etc. In addition, since an easy-printability improvement layer is laminated on the base film, it has excellent printability (print sharpness and misalignment) and water-resistant adhesion when a printing layer is provided to improve the design of molded products. ing. Furthermore, since the light transmittance at a wavelength of 380 nm is preferably kept low, it is excellent in light resistance, and can be used for the production of a decorative board or the like that imparts decorativeness by embossing for building materials and the like.

  The embossing polyester film of the present invention uses a copolymer polyester composed of an aromatic dicarboxylic acid component and ethylene glycol and a glycol component containing a branched aliphatic glycol and / or an alicyclic glycol as a base film. Including. The branched aliphatic glycol and / or alicyclic glycol has a side chain or cyclic structure that suppresses mobility such as free rotation of the molecule, and glass is obtained by copolymerizing such monomers. The melting point (Tm) can be lowered and the elongation at break can be increased without lowering the transition temperature (Tg).

  Using such a copolyester as a raw material, the polyester film of the present invention is excellent in embossability in a high temperature atmosphere during embossing, particularly in low temperature embossing, and in a room temperature atmosphere used as a molded body. Is a polyester film that has excellent characteristics in rigidity, strength, and shape stability (heat shrinkage characteristics, thickness unevenness) and is suitable for embossing.

  The above-mentioned features can be expressed by physical properties such that the stress at 100% elongation in the longitudinal direction and the width direction is 10 MPa or more and less than 180 MPa at 25 ° C. and 1 to 100 MPa at 100 ° C.

  The 100% elongation stress at 25 ° C. in the longitudinal and width directions of the film balances rigidity, strength, shape stability (thickness unevenness, heat shrinkage at 150 ° C.) and moldability at low temperature. From the point, it is important that the pressure is 10 MPa or more and less than 180 MPa.

  On the other hand, the embossing property, particularly embossing property at a low temperature, tends to be deteriorated in a film having a high rigidity such that the stress at 100% elongation in the atmosphere of 25 ° C. exceeds 180 MPa.

  In order to obtain embossability to some extent, it is necessary to heat to about 150 ° C with conventional polyester films. At this temperature, heat shrinkage may impair the finish, and the accompanying printing ink and protective film may be heat resistant. There was a problem that the selection of the material was severely restricted. On the other hand, if embossing is possible at a low temperature of about 120 ° C., there is an advantage that the problem of the heat shrinkage rate is reduced and the selection of materials to be used together is reduced. Moreover, improving the embossability at low temperature leads to energy saving.

  It is important that the stress at 100% elongation in a longitudinal direction and a width direction of the embossing polyester film of the present invention in an atmosphere of 100 ° C. is 1 to 100 MPa from the viewpoint of embossability at low temperature.

  The lower limit value of the stress at 100% elongation in the 100 ° C. atmosphere is preferably 5 MPa, particularly preferably 10 MPa. In a field where high deformability is required, a low stress at 100% elongation in an atmosphere of 100 ° C. is a desirable direction from the viewpoint of embossability at low temperatures. However, if the stress at 100% elongation in a 100 ° C. atmosphere becomes too small, the stress at 100% elongation at 25 ° C. also becomes small, and the rigidity and thickness unevenness at room temperature atmosphere deteriorate. The value is important.

  On the other hand, the stress at 100% elongation at 100 ° C. is preferably 90 MPa or less, particularly preferably 80 MPa or less, from the viewpoint of embossability at low temperatures.

  In view of embossability, the elongation at break at 100 ° C. is preferably 150% or more, more preferably 170% or more, and particularly preferably 200% or more.

  Further, from the viewpoint of rigidity, strength, and shape stability (heat shrinkage characteristics, thickness unevenness), the elongation at break at 25 ° C. is preferably 130% or more, more preferably 150% or more, particularly preferably. 170% or more.

  In the present invention, the change rate of the stress at the time of 100% elongation in the longitudinal direction and the width direction at 100 ° C. ((1 month after film formation-immediately after film formation) × 100 / immediately after film formation) However, it is preferable that both are ± 20% or less. More preferably, it is ± 10% or less, and particularly preferably ± 5% or less.

  The embossing polyester film preferably has a ratio (H / d) of haze H (%) to thickness d (μm) of less than 0.01 from the viewpoint of transparency and print sharpness. The H / d is more preferably more than 0 and less than 0.01, particularly preferably more than 0 and 0.009 or less.

  In addition, the embossing film has a haze H (%) ratio (H / d) to a thickness d (μm) of less than 0.010, which is important from the viewpoint of transparency and print sharpness. The H / d is more preferably more than 0 and less than 0.010, particularly preferably more than 0 and 0.009 or less. In the present invention, the numerical value of H / d is described in the third decimal place, but it is not rounded off after the fourth decimal place. For example, even 0.0099 is set to 0.009.

  The lower limit of the H / d is preferably closer to zero, but if the necessary minimum unevenness is not formed on the film surface, handling properties such as slipperiness and rollability will deteriorate, the film surface will be scratched or produced. The lower limit of the H / d is preferably 0.0001, and particularly preferably 0.0005.

  In the embossed polyester film of the present invention, the thickness of the film is preferably 20 to 500 μm from the viewpoints of stiffness (waist), protection of the printed layer provided on the back surface of the processed film, and design. The lower limit value of the thickness of the base film is preferably 30 μm, particularly preferably 40 μm. On the other hand, the upper limit of the thickness of the base film is preferably 300 μm, particularly preferably 200 μm.

  Moreover, it is preferable that the thickness unevenness of the polyester film for embossing of this invention is 5.5% or less. If the thickness unevenness exceeds 5.5%, the printability and dimensional stability tend to deteriorate. It is desirable that the thickness unevenness is small, but it is technically difficult to make the thickness unevenness 0.5% or less, and since there is no significant difference in practical quality, the lower limit of the thickness unevenness is 0. .5% or more is acceptable.

  Furthermore, it is preferable that the thermal shrinkage rate in the longitudinal direction and the width direction at 150 ° C. of the polyester film is 6.0% or less from the viewpoint of reducing printing deviation after the printing layer is provided on the polyester film.

  Furthermore, since the embossing polyester film of the present invention is provided with an easy-printability improving layer containing an adhesive modification resin on one side of the base film, high-quality printing is possible.

  Since the polyester film for embossing of the present invention has a light transmittance of 50% or less at a wavelength of 380 nm, the light resistance of the film is excellent.

  The polyester in the present invention means a general term for high molecular weight substances constituted by ester bonds.

  In the laminated polyester film of the present invention, a copolymer polyester comprising an aromatic dicarboxylic acid component and ethylene glycol and a glycol component containing a branched aliphatic glycol and / or an alicyclic glycol is used as a base film raw material. Use as a part or 100%.

  In the copolymerized polyester, the aromatic dicarboxylic acid component is mainly composed of terephthalic acid or an ester-forming derivative thereof. The amount of the terephthalic acid component with respect to the total dicarboxylic acid component is 70 mol% or more, preferably 85 mol% or more, particularly preferably. Is 95 mol% or more, and particularly preferably 100 mol%.

  Examples of the branched aliphatic glycol include neopentyl glycol, 1,2-propanediol, and 1,2-butanediol. Examples of the alicyclic glycol include 1,4-cyclohexanedimethanol and tricyclodecane dimethylol.

  Among these, neopentyl glycol and 1,4-cyclohexanedimethanol are particularly preferable, and the stress at 100% elongation in the longitudinal direction and the width direction of the film defined in the present invention is 10 MPa or more and less than 180 MPa and 100 ° C. at 25 ° C. Is effective for satisfying 1 to 100 MPa. Furthermore, it is preferable not only because it is excellent in embossability, particularly embossability at low temperatures and transparency, but also because it is excellent in heat resistance and improves the adhesion with the adhesive property modified layer.

  Furthermore, depending on importance, the copolymer polyester may be used in combination with one or more dicarboxylic acid components and / or glycol components as copolymer components as described below.

  Other dicarboxylic acid components that can be used in combination with terephthalic acid or its ester-forming derivatives include (1) isophthalic acid, 2,6-naphthalenedicarboxylic acid, diphenyl-4,4′-dicarboxylic acid, diphenoxyethanedicarboxylic acid Aromatic dicarboxylic acids such as acid, diphenylsulfone dicarboxylic acid, 5-sodium sulfoisophthalic acid, phthalic acid or their ester-forming derivatives, (2) oxalic acid, succinic acid, adipic acid, sebacic acid, dimer acid, maleic acid Aliphatic dicarboxylic acids such as fumaric acid and glutaric acid or ester-forming derivatives thereof; (3) alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid or ester-forming derivatives thereof; (4) p-oxybenzoic acid; Oxycarboxylic acids such as oxycaproic acid or their esters And forming derivatives.

  On the other hand, examples of other glycol components that can be used together with ethylene glycol and branched aliphatic glycol and / or alicyclic glycol include 1,3-propanediol, 1,4-butanediol, pentanediol, and hexane. Examples include aliphatic glycols such as diols, aromatic glycols such as bisphenol A and bisphenol S, and ethylene oxide adducts thereof, diethylene glycol, and triethylene glycol.

  Furthermore, if necessary, the copolymer polyester may be further copolymerized with a polyfunctional compound such as trimellitic acid, trimesic acid, or trimethylolpropane.

  Examples of the catalyst used for producing the copolymer polyester include alkaline earth metal compounds, manganese compounds, cobalt compounds, aluminum compounds, antimony compounds, titanium compounds, titanium / silicon composite oxides, and germanium compounds. . Among these, titanium compounds, antimony compounds, and germanium compounds are preferable from the viewpoint of catalytic activity.

  When producing the copolymer polyester, it is preferable to add a phosphorus compound as a heat stabilizer. As said phosphorus compound, phosphoric acid, phosphorous acid, etc. are preferable, for example.

  The copolymer polyester preferably has an intrinsic viscosity of 0.50 to 1.0 dl / g or more from the viewpoints of moldability, adhesiveness, and film formation stability. The upper limit of the intrinsic viscosity of the copolyester is preferably 0.95 dl / g, particularly preferably 0.90 dl / g, from the viewpoint of ejection stability from the extruder. On the other hand, the lower limit is preferably 0.55 dl / g, particularly preferably 0.60 dl / g, from the viewpoint of film-forming stability and mechanical strength. Moreover, as a polyester film for shaping | molding, the intrinsic viscosity of the range of 0.60-0.80 dl / g is preferable from the point of a moldability.

  For the base film in the laminated polyester film of the present invention, the copolymer polyester may be used as it is as a film raw material, or a copolymer polyester containing a large amount of copolymer components is blended with a homopolyester to adjust the amount of copolymer components. It doesn't matter.

  Moreover, it is preferable from the point of a moldability to blend 2 or more types of the said copolyester, and to use as a raw material of the base film in the laminated polyester film of this invention. Among these, a mixed polymer obtained by blending polyneopentene terephthalate and / or polycyclohexanedimethylene terephthalate with polyethylene terephthalate is particularly preferable from the viewpoint of flexibility and moldability.

  The melting point of the polyester base film is preferably 220 to 245 ° C. from the viewpoint of heat resistance and moldability. Here, the melting point is an endothermic peak temperature at the time of melting, which is detected at the time of primary temperature rise in so-called differential scanning calorimetry (DSC). The melting point is V4. OB2000 type differential scanning calorimetry was used to measure and determine at a temperature elevation rate of 20 ° C./min.

  The lower limit of the melting point of the polyester base film is more preferably 225 ° C, particularly preferably 230 ° C. If the melting point is less than 220 ° C, the heat resistance tends to deteriorate. Therefore, it may become a problem when exposed to high temperatures during molding or use of the molded body. The upper limit of the melting point is better from the viewpoint of heat resistance, but when the main component is a polyethylene terephthalate unit, it is difficult to ensure transparency with a film having a melting point of 245 ° C or higher in order to ensure high transparency and flexibility. It is important to lower the melting point, and the upper limit value is 245 ° C. Furthermore, when it is going to obtain high transparency, the upper limit of melting | fusing point will be 240 degreeC. In order to solve this problem, it is achieved by melt-mixing a high melting point polyester (PET) and a low melting point copolymer polyester. By forming a film using a melt blend, it achieves the same flexibility and high melting point when using 100% copolyester, and when using only high melting point polyester, High transparency and a melting point with no practical problems can be realized.

  The embossed polyester film of the present invention is preferably an unstretched film in terms of embossability, but a biaxially stretched polyester film is preferable from the viewpoint of heat resistance and dimensional stability. Such a biaxial stretching method may be either simultaneous biaxial stretching or sequential biaxial stretching.

  The method for producing the polyester base film is not particularly limited. For example, after drying the polyester as important, it is supplied to a known melt extruder, extruded into a sheet from a slit die, electrostatic application, etc. The method of sticking to a casting drum by this method, cooling and solidifying to obtain an unstretched sheet, and then biaxially stretching the unstretched sheet is exemplified.

  Such a stretching method may be either simultaneous biaxial stretching or sequential biaxial stretching. In short, the unstretched sheet is stretched and heat-treated in the longitudinal direction (MD) and the width direction (TD) of the film, and the intended surface. A method of obtaining a biaxially stretched film having an internal orientation degree is employed. Among these methods, in terms of film quality, the MD / TD method in which the film is stretched in the longitudinal direction and then stretched in the width direction, or the TD / MD method in which the film is stretched in the width direction and then stretched in the longitudinal direction. An axial stretching method and a simultaneous biaxial stretching method in which the longitudinal direction and the width direction are stretched almost simultaneously are desirable. Furthermore, depending on the importance, a multistage stretching method in which stretching in the same direction is performed in multiple stages may be used.

  The film stretching ratio when biaxially stretching is preferably 1.6 to 4.2 times in the longitudinal direction and the width direction, particularly preferably 1.7 to 4.0 times. In this case, the stretching ratio in the longitudinal direction and the width direction may be either larger or the same ratio.

  In the laminated polyester film of the present invention, as a raw material for the base film, (1) a copolymer polyester comprising terephthalic acid and ethylene glycol or neopentyl glycol, or (2) terephthalic acid and ethylene glycol, 1,4-cyclohexanedimethanol In the case of using a copolyester composed of the following, in order that the stress at 100% elongation in the longitudinal direction and the width direction is 10 MPa or more and less than 180 MPa at 25 ° C. and 1 to 100 MPa at 100 ° C., the stretching ratio in the longitudinal direction is 2 It is preferable to carry out at a ratio of 0.8 to 4.0 times and a stretching ratio in the width direction of 3.0 to 4.5 times.

  The stretching conditions for producing the laminated polyester film of the present invention are not particularly limited. However, in order to satisfy the range of stress at 100% elongation at 25 ° C. and 100 ° C. defined in the present invention, it is preferable to adopt the following conditions, for example.

  In the longitudinal stretching, the stretching temperature is preferably 50 to 110 ° C. and the stretching ratio is preferably 1.5 to 4.0 times so that the subsequent lateral stretching can be performed smoothly.

  In transverse stretching, stress at 100% elongation in the longitudinal direction and the width direction is particularly important because the stress is 10 MPa or more and less than 180 MPa and 1 to 100 MPa at 100 ° C.

  Usually, when stretching the polyethylene terephthalate, if the stretching temperature is lower than the appropriate conditions, the yield stress increases rapidly at the beginning of the lateral stretching, and therefore stretching cannot be performed. Moreover, even if it can extend | stretch, since thickness and a draw ratio become easy to become nonuniform, it is unpreferable.

  In addition, when the stretching temperature is higher than appropriate conditions, the initial stress is low, but the stress does not increase even when the stretch ratio is high. Therefore, the film has a small stress at 100% elongation at 25 ° C. Therefore, by taking the optimum stretching temperature, a highly oriented film can be obtained while ensuring stretchability.

  However, when the copolymer polyester, which is a raw material of the polyester base film, contains 1 to 40 mol% of a copolymer component, the stretching stress decreases rapidly when the stretching temperature is increased so as to eliminate the yield stress. . In particular, since the stress does not increase even in the latter half of the stretching, the orientation does not increase and the stress at 100% elongation at 25 ° C. decreases.

  Such a phenomenon is likely to occur when the thickness of the film is 60 to 500 μm, and is particularly noticeable in a film having a thickness of 100 to 300 μm. Therefore, for example, in the case of a film using polyester copolymerized with neopentyl glycol or 1,4-cyclohexanedimethanol, the stretching temperature in the transverse direction is preferably set as follows.

  First, the preheating temperature is 90 to 120 ° C., the stretching temperature is 5 to 25 ° C. higher than the preheating temperature in the first half of the transverse stretching, and the stretching temperature is higher than the stretching temperature in the first half of the transverse stretching. It is preferable to lower the temperature by 15 to 40 ° C. By adopting such conditions, the first half of the transverse stretching is easy to stretch because the yield stress is small, and the second half is easily oriented. In addition, it is preferable that the draw ratio of a horizontal direction shall be 2.5 to 5.0 times. As a result, it is possible to obtain a film in which the stress at 100% elongation in the longitudinal direction and the width direction satisfies 10 MPa or more and less than 180 MPa at 25 ° C. and 1 to 100 MPa at 100 ° C.

  Further, the film is subjected to heat treatment after biaxial stretching, and this heat treatment can be performed by a conventionally known method such as in an oven or on a heated roll. Further, the heat treatment temperature and the heat treatment time can be arbitrarily set according to the level of the heat shrinkage rate which is important. The heat treatment temperature is preferably in the range of 120 to 245 ° C, particularly preferably 150 to 230 ° C. The heat treatment time is preferably 1 to 60 seconds. In addition, you may perform this heat processing, relaxing a film to the longitudinal direction and / or the width direction. In order to reduce the thermal shrinkage in the longitudinal direction and the lateral direction at 150 ° C., it is preferable to increase the heat treatment temperature, lengthen the heat treatment time, and perform relaxation treatment. It is difficult to lengthen the line and increase the heat treatment time due to equipment limitations. Further, when the film feed rate is slowed, productivity is lowered.

  In order to set the heat shrinkage rate in the longitudinal direction and the width direction at 150 ° C. to 6.0% or less, it is preferable to perform the heat treatment at 200 to 220 ° C. while relaxing at a relaxation rate of 1 to 8%. Furthermore, re-stretching may be performed once or more in each direction, and then heat treatment may be performed.

  The embossing polyester film of the present invention is important in that an easy-printability improving layer containing an adhesive modified resin is laminated on at least one surface of the base material. As a result, the adhesion to UV ink and solvent ink can be improved, and the finish and durability of printing can be improved.

  In the present invention, the composition and the laminating method thereof are not limited as long as they have a function of improving the adhesion between the base polyester film and the printing ink. In a preferred embodiment, the printability improving layer is made of at least one resin selected from the group consisting of polyester resins, polyurethane resins, and acrylic resins, and is formed by an in-line coating method. The structure of the resin is not limited, but is preferably noncrystalline or low crystalline. Moreover, you may bridge | crosslink the said resin with a crosslinking agent for a water resistant factory as needed.

  In the embossing polyester film of the present invention, it is important to provide an easy-printability improving layer on at least one surface of the polyester base film in order to improve printability.

The resin constituting the easy printability improving layer, polyester or Ranaru resin. In addition, when the substrate film contains substantially no particles, it contains one or more particles in the adhesion modified layer from the viewpoint of improving handling properties (sliding property, winding property, blocking resistance, etc.). It is preferable to make it.

  Furthermore, as the polyester-based resin constituting the easy-printability improving layer, 0.5 to 15.0 mol% of an unsaturated group-containing dicarboxylic acid, and 85.0 to 99.5 mol% of a dicarboxylic acid not containing an unsaturated group, Using a resin in which a water-insoluble polyester copolymer obtained by reacting the two types of dicarboxylic acid components with the polyol component is graft-modified with an unsaturated bond-containing monomer improves the water-resistant adhesion of the printing ink layer. This is a preferred embodiment in terms of improvement.

  Examples of the unsaturated group-containing dicarboxylic acid include fumaric acid, maleic acid, maleic anhydride, itaconic acid, citraconic acid, 2,5-norbornene dicarboxylic acid, 4-cyclohexene-1,2-dicarboxylic acid, and the like. Of these unsaturated group-containing dicarboxylic acids, fumaric acid and maleic acid are particularly preferred.

  It is preferable that these unsaturated group containing dicarboxylic acid components are 0.5-15.0 mol% with respect to all the dicarboxylic acid components. The composition ratio of the unsaturated group-containing dicarboxylic acid component to the total dicarboxylic acid component is particularly preferably set to a lower limit of 2.0 mol% from the viewpoint of water-solubilization or water-dispersion of the resin, and is intended to suppress gel generation. From the above, it is particularly preferable to set the upper limit to 10.0 mol%. When the composition ratio is less than 0.5 mol%, graft modification is not sufficiently performed, so that it becomes difficult to obtain a water-soluble or water-dispersible resin. On the other hand, if the composition ratio exceeds 15.0 mol%, a gel is generated due to graft modification, making it difficult to obtain a resin suitable for coating.

  As the dicarboxylic acid component not containing an unsaturated group, aromatic, alicyclic, and aliphatic dicarboxylic acids can be used. Examples of aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, orthophthalic acid, 2,6-naphthalenedicarboxylic acid, 5-sodium sulfoisophthalic acid, 4-sulfoterephthalic acid, 4-sulfonaphthalene-2,7-dicarboxylic acid, Examples include 5 [4-sulfophenoxy] isophthalic acid.

  These aromatic dicarboxylic acids are preferably 40 mol% or more with respect to the total dicarboxylic acid component, and if it is less than 40 mol%, the mechanical strength and water resistance of the polyester copolymer tend to be lowered.

  Examples of the aliphatic or alicyclic dicarboxylic acid include succinic acid, adipic acid, sebacic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, and the like. When these aliphatic or alicyclic dicarboxylic acid components are contained, the adhesion may be improved, but generally there is a tendency to lower the mechanical strength and water resistance of the polyester copolymer.

  Examples of the polyol component to be reacted with the two kinds of dicarboxylic acids include (1) ethylene glycol, 1,2-propylene glycol, 1,3-propanediol, 1,4-butanediol, neopentyl glycol, 1,6- C2-C8 aliphatic glycols such as hexanediol, (2) C6-C12 such as 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol Alicyclic glycol, (3) aromatic glycol such as p-xylylene glycol, (4) glycol having an ether bond such as diethylene glycol, triethylene glycol, (5) polyethylene glycol, polypropylene glycol, polytetramethylene glycol, etc. Polyether, etc. It is. Further, a copolymer obtained by copolymerizing an oxycarboxylic acid component such as p-oxyethoxybenzoic acid may be used.

  The unsaturated group-containing monomer used for graft-modifying the unsaturated polyester is preferably a monomer that is polymerized by radicals. For example, acrylic acid, acrylic acid esters (methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, hydroxypropyl acrylate, etc.), methacrylic acid , Methacrylate (Methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-hexyl methacrylate, lauryl methacrylate, 2-hydroxyethyl methacrylate, hydroxypropyl methacrylate, etc. ), Acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, N-methylol acrylamide, diacetone acrylamide, vinyl acetate, vinyl ethers, N-vinyl Pyrrolidone, styrene, alpha-methyl styrene, t- butyl styrene, vinyl toluene, maleic anhydride.

  These monomers can be used alone or in combination of two or more. Preferably, a resin graft-modified with a monomer containing acrylic acid and ethyl acrylate, or a resin graft-modified with a monomer containing styrene and maleic anhydride is a water-dispersible, adhesive modified layer and a base film. And from the viewpoint of improving adhesion to the printing ink layer, heat resistance, and water resistance.

  Regarding graft modification, methods disclosed in JP-A-6-256737 and JP-A-7-330841 can be used.

  As the method of providing the easy-printability improving layer, as described above, there is a method of applying the coating liquid containing the composition for easy-printability improving layer mainly composed of the adhesive modified resin by the in-line coating method. preferable.

  At this time, the liquid temperature of the coating solution is preferably controlled to 10 ° C. to 20 ° C., and particularly preferably set to 12 ° C. to 18 ° C. Moreover, it is preferable to adjust pH of a coating liquid to 5.5-7.5, Especially preferably, it is 6.0-7.0.

  If the liquid temperature or pH of the coating liquid is outside the above range, when particles are contained in the coating liquid, the inert particles in the coating liquid are likely to aggregate and production due to clogging of the filter in the coating liquid circulation system Deterioration and powder resistance of the adhesiveness modified layer are likely to decrease. Furthermore, the aging stability (pot life) of the coating solution tends to decrease.

  In addition, before applying the coating solution to the base film, the coating solution is filtered using a filter such as a wire mesh, a bag filter, a pincushion filter, or a cartridge filter, so that coarse particles, agglomerated particles, and contaminants are collected. Etc. are preferably removed.

  In this way, by controlling the liquid temperature and pH of the coating liquid within the above range, or by filtering the coating liquid using the filter, the printed appearance is improved when the printed layer is provided on the laminated polyester film. Can be good.

  In addition, as a method of applying the coating solution for the adhesion modified layer to the base film, a roll coating method such as gravure coating, reverse coating, kiss coating, and reverse kiss coating, a bar coating method, an air knife method, a blade coating method, and a comma. Conventionally used methods such as a coat (roll knife coat) method, a curtain coat method, a spray method, and a dip method can be applied.

  As the step of applying to the polyester film, any method such as a method of applying in advance to the surface of the unstretched film, a method of applying the film in the uniaxial direction and then applying it to the film surface and then orienting in the perpendicular direction is possible. Among them, the method of stretching and orienting in the direction perpendicular to the uniaxially oriented polyester film surface to complete crystallization is superior in terms of heat resistance, adhesiveness, economic efficiency, and cleanliness during molding. This is the preferred method.

  Further, it is preferable to form irregularities on the film surface in order to improve handling properties such as slipperiness and winding property of the film. As a method for forming irregularities on the film surface, a method of incorporating particles in the film is generally used. However, since the particles contained in the film generally have a refractive index different from that of polyester, it causes a decrease in the transparency of the film.

  Therefore, in order to increase the transparency of the film while maintaining the handleability of the film, it is effective to contain particles only in the easy-printability improving layer without substantially containing particles in the base film. Yes, it is one of suitable means for setting the ratio (H / d) of haze H (%) to the thickness d (μm) of the laminated film to be less than 0.01. The object can also be achieved by a method in which particles are contained only in an extremely thin surface layer by coextrusion.

  The phrase “substantially contain no particles in the base film” as used above means, for example, in the case of inorganic particles, a content that is below the detection limit when inorganic elements are quantified by fluorescent X-ray analysis. . This is because contaminant components derived from foreign substances may be mixed without intentionally adding the particles to the adhesion-modified layer.

  Examples of the particles contained in the easy-printability improving layer include inorganic particles and / or organic particles having an average particle size of 0.01 to 10 μm. Two or more kinds of these inorganic particles and / or organic particles may be used in combination, depending on importance.

  When the easy-printability improving layer contains particles having an average particle diameter of more than 10 μm, the frequency with which coarse protrusions are formed on the film surface increases and the designability tends to deteriorate. On the other hand, in the case of particles having an average particle diameter of less than 0.01 μm, handling properties such as film slipperiness and winding property tend to be lowered.

  Examples of the inorganic particles include wet method silica, dry method silica, colloidal silica, glass filler, titanium oxide, alumina, aluminum silicate, mica, kaolin, clay, zeolite, alumina-silica composite oxide particles, hydroxyapatite, carbonic acid. Examples include calcium, calcium phosphate, and barium sulfate.

  Examples of organic particles include particles containing styrene, silicone, acrylic acid, methacrylic acid, polyester, divinylbenzene and the like as constituent components.

  Among these particles, silica particles, glass fillers, and silica-alumina composite oxide particles are particularly suitable from the viewpoint of transparency because the refractive index is relatively close to that of polyester.

  Furthermore, the particle content in the easy-printability improving layer is preferably in the range of 0.01 to 25% by mass. When the content is less than 0.01% by mass, handling properties are likely to deteriorate, for example, the slipperiness of the film is deteriorated or winding becomes difficult. On the other hand, when it exceeds 25 mass%, transparency and applicability tend to deteriorate.

  Although it is preferable to implement the said polyester base film by single layer structure from the point of economical efficiency, it does not restrict | limit at all to make polyester into a multilayer structure by a well-known method using different kind of polyester. The multilayer structure of the base film is not particularly limited, and examples thereof include A / B type 2 layers, B / A / B type 2 layers, C / A / B type 3 layers, and the like.

  The embossing polyester film of the present invention has an important light transmittance of 50% or less at a wavelength of 380 nm, preferably 35% or less, and particularly preferably 20% or less. If the light transmittance at a wavelength of 380 nm exceeds 50%, the light resistance of the polyester film for molding, particularly the printed layer when the film is printed, deteriorates.

  The method for adjusting the light transmittance at a wavelength of 380 nm to 50% or less is optional without limitation, and a method of containing an ultraviolet absorber in at least one of the substrate and the easy-printability improving layer in the embossed polyester film. Recommended.

  The ultraviolet absorber used in the above method may be appropriately selected without limitation as long as it can impart the above-mentioned characteristics. Either inorganic or organic may be used. Examples of organic ultraviolet absorbers include benzotoazole, benzophenone, cyclic imino ester, and combinations thereof. 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, 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] -2 -Benzotriazole, 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. However, it is not particularly limited to these.

  Examples of the cyclic imino ester ultraviolet absorber include 2,2 ′-(1,4-phenylene) bis (4H-3,1-benzoxazinon-4-one), 2-methyl-3,1-benzo. Oxazin-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-nitro Phenyl-3,1-benzoxazin-4-one, 2-p-benzoylphenyl-3,1-benzoxazin-4-one, 2-p-methoxyphenyl-3,1-benzoxazin-4-one, 2 -O-metoki Phenyl-3,1-benzoxazin-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-benzoxazin-4-one), 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-benzoxazine-4 -On), 2,2 '-(4 4'-diphenylene) bis (3,1-benzoxazin-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-benzoxazine -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-one-2-yl) benzene, 1,3,5-tri (3,1-benzoxazine- 4-On-2-yl) naphthalene and 2,4,6-tri (3,1- Nzookisajin-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, '-Methylenebis (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 ( -Methyl-4H, 3,1-benzoxazin-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) and the like, but is not particularly limited thereto.

  When blending the organic ultraviolet absorber into the base film, it is exposed to a high temperature in the extrusion process. Therefore, it is necessary to use an ultraviolet absorber having a thermal decomposition starting temperature of 290 ° C. or more at the time of film formation. It is preferable in reducing process contamination. If an ultraviolet absorber having a thermal decomposition start temperature of 290 ° C or lower is used, the decomposed product of the ultraviolet absorber adheres to the roll group of the manufacturing apparatus during film formation, and may reattach to the film or be damaged. This is not preferable because it causes optical defects.

  Examples of inorganic ultraviolet absorbers include ultrafine particles of metal oxides such as cerium oxide, zinc oxide, and titanium oxide.

  As another method for reducing the light transmittance at a wavelength of 380 nm to 50% or less, a method of using a compound having an absorption in this wavelength region, such as naphthalene dicarboxylic acid, for example, as a copolymerization component of polyester. be able to.

Hereinafter, the present invention will be described in detail using examples. In addition, the characteristic of the film obtained by each Example was measured and evaluated with the following method.
(1) Intrinsic viscosity 0.1 g of the chip sample was precisely weighed and dissolved in 25 ml of a mixed solvent of phenol / tetrachloroethane = 6/4 (mass ratio), and measured at 30 ° C. using an Ostwald viscometer. In addition, the measurement was performed 3 times and the average value was calculated | required.

(2) Thickness unevenness A continuous tape-like sample having a length of 3 m in the transverse stretching direction and a length of 5 cm in the longitudinal stretching direction is wound up, and the thickness of the film is measured with a film thickness continuous measuring machine (manufactured by Anritsu Corporation). To record. From the chart, the maximum value (dmax), the minimum value (dmin), and the average value (d) of the thickness were obtained, and the thickness unevenness (%) was calculated by the following formula. In addition, the measurement was performed 3 times and the average value was calculated | required. Moreover, when the length of a horizontal extending direction is less than 3 m, it joins and performs. The connecting part is deleted from the data.
Thickness unevenness (%) = ((dmax−dmin) / d) × 100

(3) Haze Based on JIS-K7136, it measured using the haze meter (Nippon Denshoku Industries Co., Ltd. make, 300A). In addition, the measurement was performed twice and the average value was calculated | required.

(4) Film Thickness Using a millitron, a total of 15 points were measured, 5 points per sheet, and the average value was determined.

(5) Stress at 100% elongation, elongation at break With respect to the longitudinal direction and width direction of the biaxially stretched film, a sample was cut into a strip shape having a length of 180 mm and a width of 10 mm, respectively, with a single-blade razor, and the sample was pulled. The sample was pulled using Toyo Seiki Co., Ltd., and the stress at 100% elongation (MPa) and elongation at break (%) in each direction were determined from the obtained load-strain curve.

  The measurement was performed in an atmosphere of 25 ° C. under the conditions of an initial length of 40 mm, a distance between chucks of 100 mm, a crosshead speed of 100 mm / min, a recorder chart speed of 200 mm / min, and a load cell of 25 kgf. The measurement was performed 10 times and the average value was used.

  In addition, a tensile test was performed under the same conditions as described above even in an atmosphere at 100 ° C. At this time, the sample was held for 30 seconds in an atmosphere at 100 ° C. and then measured. The measurement was performed 10 times and the average value was used.

(6) Thermal contraction rate at 150 ° C. A strip sample having a length of 250 mm and a width of 20 mm is cut out in the longitudinal direction and the width direction of the film, respectively. Two marks are marked at intervals of 200 mm in the length direction of each sample, and the distance A between the two marks is measured under a constant tension (tension in the length direction) of 5 g. Subsequently, one side of each strip-shaped sample is hung with a clip on a basket under no load, and placed in a gear oven under an atmosphere of 150 ° C., and time is taken. After 30 minutes, the basket is removed from the gear oven and left at room temperature for 30 minutes. Next, for each sample, the distance B between the two marks is read with a gold finger in units of 0.25 mm under a constant tension of 5 gf (longitudinal tension). From the read intervals A and B, the thermal shrinkage rate at 150 ° C. of each sample is calculated by the following formula.
Thermal contraction rate (%) = ((A−B) / A) × 100

(7) Embossability The film was heated to 130 ° C. and passed between an embossing roll having a depth of 200 μm and 20 μm and a pressure cooling roll (2 kgf / cm). Next, the ratio (Df / De) of the embossed part depth Df of the embossed film surface to the embossed roll unevenness depth De was used as a measure of embossing formability, and the following criteria were used.
○: More than 70% and less than 100% △: 50% or more and less than 70% ×: Less than 50%

(8) Printability The film before printing was heat-treated at 90 ° C. for 30 minutes, and then four-color screen printing was performed. Furthermore, the film provided with the printing layer was dried at 80 ° C. for 30 minutes. The printability was evaluated based on the following criteria by visual evaluation of print misalignment and print sharpness. In addition, (double-circle) and (circle) were set as the pass, and x was set as the disqualification.

(Double-circle): It is excellent in print clarity and the printing shift | offset | difference in each color is not observed visually.
○: Some printing misalignment is observed when visually observed at a position of about 20 cm, but 20 cm
When the distance is more than the above, the appearance is generally good and is practically usable.
X: Printing misalignment in each color is observed or printing is uneven, and the appearance is remarkably bad.

(9) Ultraviolet transmittance The light transmittance at a wavelength of 380 nm was measured using a double beam type spectrophotometer (Hitachi, U-2001).

(10) Light resistance Using the printing sample used in the paper feeding stability evaluation, in the dark box, the printed surface is on the back side at a position 3 cm directly below the fluorescent lamp (Matsushita Electric Corp., U-type fluorescent lamp FUL9EX). installed. Subsequently, irradiation was continuously performed for 2000 hours, and the color difference (ΔE) before and after irradiation on the printing surface side was measured according to JIS-Z8730, and the case where the ΔE value was 0.5 or less was regarded as acceptable.

Reference example 1
(Coating solution adjustment)
Water-soluble urethane resin (Daily Kogyo Seiyaku Co., Ltd., Elastron) with 3.15% by weight of solid content of copolymer polyester resin (Toyobo Co., Ltd., Vylonal MD1250) and solid end isocyanate groups blocked with hydrophilic groups H-3) is 5.85% by mass in terms of solid content, 12.0% by mass of silica particles having an average particle size of 0.05 μm, and 0.5% by mass of silica particles having an average particle size of 0.2 μm with respect to the total resin As a result, it was added to a 40% by weight aqueous solution of isopropanol so as to contain 12.5% by weight and uniformly mixed to prepare a coating solution. The obtained coating solution was adjusted to pH 6.5 using a 5% by mass aqueous sodium bicarbonate solution. Subsequently, it filtered with the bag type filter (Sumitomo 3M Co., Ltd. product, liquid filter bag), and stirred at 15 degreeC in the coating liquid circulation system stock tank for 2 hours.

(Manufacture of laminated film)
Copolyester (A) having an intrinsic viscosity of 0.69 dl / g, comprising 100 mol% of terephthalic acid units as aromatic dicarboxylic acid components, 40 mol% of ethylene glycol units and 60 mol% of neopentyl glycol units as diol components. And polyethylene terephthalate (B) having an intrinsic viscosity of 0.69 dl / g, respectively, and then used for chip blending at 25:75 (mass ratio), and using an extruder having a T die at 280 ° C. It was melt extruded and rapidly solidified on a drum having a surface temperature of 40 ° C. to obtain an amorphous sheet. Both copolymer polyester (A) and polyethylene terephthalate (B) were blended with 0.5 parts by weight of benzotriazole-based UV absorber (manufactured by Ciba Specialty Chemicals Co., Ltd., Tinuvin 326) with respect to 100 parts by weight of polyester.

  The obtained sheet was stretched 3.5 times at 92 ° C. in the longitudinal direction between the heating roll and the cooling roll. The above coating solution was applied to one side of the obtained uniaxially stretched film by a reverse kiss coating method so that the resin solid content thickness before stretching was 0.9 μm. The film having the coating layer is guided to a tenter while being dried, preheated at 100 ° C. for 15 seconds, the first half of the transverse stretching is stretched by 115 ° C. and the latter half is stretched 3.6 times at 95 ° C., and the lateral relaxation is 7%. Was carried out at 205 ° C. to obtain a laminated biaxially stretched polyester film having a thickness of 75 μm. The characteristics and evaluation results of the obtained film are shown in Table 1.

Comparative Example 1
100 mol% of terephthalic acid units as aromatic dicarboxylic acid components, 85 mol% of ethylene glycol units and 15 mol% of neopentylglycol units as diol components, and 400 ppm of amorphous silica having an average particle size of 1.5 μm The copolyester having an intrinsic viscosity of 0.69 dl / g is pre-crystallized and then dried, melt-extruded at 280 ° C. using an extruder having a T die, and rapidly cooled and solidified on a drum having a surface temperature of 40 ° C. A regular sheet was obtained.

  The obtained sheet was stretched 3.5 times at 92 ° C. in the longitudinal direction between the heating roll and the cooling roll. The resulting uniaxially stretched film is guided to a tenter, preheated at 100 ° C. for 15 seconds, the first half of the transverse stretching is stretched 3.6 times at 115 ° C. and the latter half is 95 ° C., and the transverse relaxation is 7%. Then, heat treatment was performed at 205 ° C. to obtain a biaxially stretched polyester film having a thickness of 75 μm. The characteristics and evaluation results of the obtained film are shown in Table 1.

Reference example 2
In Example 1, the content of silica in the coating solution was 12.5% by mass to 29.5% by mass (28.0% by mass of silica particles having an average particle size of 0.05 μm and silica particles having an average particle size of 0.2 μm). A laminated biaxially stretched polyester film was obtained in the same manner as in Reference Example 1 except that the content was changed to 1.5% by mass. The properties and evaluation results of the obtained film are shown in Tables 1 and 2.

Comparative Example 2
In Reference Example 1, the raw material of the film is composed of 100 mol% terephthalic acid unit as the aromatic dicarboxylic acid component, 85 mol% ethylene glycol unit and 15 mol% neopentylglycol unit as the diol component, and an average particle size of 1 A laminated biaxially stretched polyester film was obtained in the same manner as in Reference Example 1 except that a copolyester having an intrinsic viscosity of 0.69 dl / g and containing 400 ppm of 0.5 μm amorphous silica was used. The characteristics and evaluation results of the obtained film are shown in Table 1.

Comparative Example 3
Polyethylene terephthalate having an intrinsic viscosity of 0.69 dl / g consisting of 100 mol% of terephthalic acid unit as an aromatic dicarboxylic acid component and 100 mol% of ethylene glycol unit as a diol component is pre-crystallized and then dried and extruded with a T die. It was melt-extruded at 280 ° C. using a machine and rapidly solidified on a drum having a surface temperature of 40 ° C. to obtain an amorphous sheet.

  The obtained sheet | seat was extended | stretched 3.7 times at 97 degreeC in the vertical direction between the heating roll and the cooling roll. The coating solution was applied to one side of the obtained uniaxially stretched film by a reverse kiss coating method so that the resin solid content thickness before stretching was 0.9 μm. The film having the coating layer is dried and guided to a tenter, preheated at 100 ° C. for 15 seconds, the first half of the transverse stretching is stretched 4.0 times at 120 ° C. and the latter half is 120 ° C., and 10% lateral relaxation is achieved. Then, heat treatment was performed at 230 ° C. to obtain a laminated biaxially stretched polyester film having a thickness of 75 μm. The characteristics and evaluation results of the obtained film are shown in Table 1.

Reference example 3
Copolyester (C) having an intrinsic viscosity of 0.71 dl / g, comprising 100 mol% terephthalic acid unit as the aromatic dicarboxylic acid component, 70 mol% ethylene glycol unit and 30 mol% cyclohexanedimethanol unit as the diol component And polyethylene terephthalate (B) were chip-blended at 30:70 (mass ratio). Next, the chip mixture was dried, melt extruded at 280 ° C. using an extruder having a T die, and rapidly cooled and solidified on a drum having a surface temperature of 40 ° C. to obtain an amorphous sheet. Both copolymerized polyester (C) and polyethylene terephthalate (B) were blended with 0.5 parts by weight of benzotriazole-based UV absorber (manufactured by Ciba Specialty Chemicals Co., Ltd., Tinuvin 326) with respect to 100 parts by weight of polyester.

The obtained sheet | seat was extended | stretched 3.0 times at 85 degreeC in the vertical direction between the heating roll and the cooling roll. The same coating liquid as in Reference Example 1 was applied to one side of the obtained uniaxially stretched film by a reverse kiss coating method so that the resin solid content thickness before stretching was 0.9 μm. The film having the coating layer is dried and guided to a tenter, preheated at 105 ° C. for 15 seconds, the first half of the transverse stretching is stretched 3.6 times at 125 ° C. and the latter half is 98 ° C., and the lateral relaxation is 7%. Was carried out at 205 ° C. to obtain a laminated biaxially stretched polyester film having a thickness of 75 μm. The characteristics and evaluation results of the obtained film are shown in Table 1.

Reference example 4
In Reference Example 1, after the copolymerized polyester (A) and the polyethylene terephthalate (B) having an intrinsic viscosity of 0.69 dl / g were dried, they were used after being chip-blended at 33:67 (mass ratio). Except for this, a biaxially stretched polyester film was obtained in the same manner as in Example 1.

Example 5
(Coating solution adjustment)
The dicarboxylic acid component is a terephthalic acid unit 50 mol%, the isophthalic acid unit 45 mol%, the fumaric acid 5 mol%, the diol component is an ethylene glycol unit 50 mol%, and neopentyl glycol 50 mol%. .80 parts by mass of polyester of 50 dl / g, 10 parts by mass of styrene as a monomer, 10 parts by mass of maleic anhydride, and 6 parts by mass of azobisisobutyronitrile as a polymerization initiator with respect to the total amount of the monomers The graft modification was performed in a 2-butanone solution containing 20% by mass of isopropanol at a temperature of 80 ° C.

  After the grafting reaction, the acid anhydride (maleic anhydride) site was opened with ethanol and neutralized with ammonia. Subsequently, the solvent was replaced with water, and a graft modified polyester resin dispersion having a number average molecular weight of 17,000 measured by GPC, a resin acid value before neutralization of 900 eq / ton, and a solid content concentration of 25% by mass was obtained. .

(Manufacture of laminated film)
In Reference Example 1, a laminated polyester film was obtained in the same manner as Reference Example 1 except that the graft modified polyester resin dispersion obtained above was used as the coating solution. The characteristics and evaluation results of the obtained film are shown in Table 1.

Reference Example 6
As a coating solution, acrylic resin (Dainippon Ink Industry Co., Ltd., Boncoat R-3380A) and melamine resin (Sumitomo Chemical Co., Ltd., Sumimar M-40W) are each in a mass ratio of resin solids of 70/30. A laminated polyester film was obtained in the same manner as in Reference Example 1 except that a mixture was used. The characteristics and evaluation results of the obtained film are shown in Table 1.

The embossing polyester film of the present invention has the following advantages and is very useful industrially.
That is, it has excellent embossability, especially embossability at low temperatures, excellent rigidity and shape stability (heat shrinkage characteristics, thickness unevenness) when used as a molded product, and excellent printability and light resistance. Therefore, it is useful particularly for building materials that require light resistance and decorative properties. In particular, it is suitable as a surface layer material such as a decorative board to which decorativeness is imparted by embossing.

Claims (11)

A polyester film comprising a copolymerized polyester composed of an aromatic dicarboxylic acid component, ethylene glycol, and a glycol component containing a branched aliphatic glycol and / or an alicyclic glycol,
The film has a ratio (H / d) of haze H (%) to thickness d (μm) of less than 0.010,
The film has a stress at 100% elongation in the longitudinal and width directions of 10 MPa or more and less than 180 MPa at 25 ° C. and 1 to 100 MPa at 100 ° C.,
Furthermore, an easy printability improving layer containing polyester on at least one side is provided by an inline coating method,
The polyester which comprises the said easy-printability improvement layer is two types, 0.5-15.0 mol% of unsaturated group containing dicarboxylic acid, and 85.0-99.5 mol% of dicarboxylic acid which does not contain an unsaturated group A polyester film for molding, which is a resin obtained by graft-modifying a water-insoluble polyester copolymer obtained by reacting the dicarboxylic acid component with a polyol component with an unsaturated bond-containing monomer. Molding the polyester film of claim 1, wherein a light transmittance at a wavelength of 380nm is 50% or less.   The polyester film for molding according to claim 1 or 2, wherein the film has a melting point of 220 to 245 ° C. Substantially without containing particles, molding the polyester film according to claim 1, characterized in that it contains the particles only in the easy printability improving layer on a substrate film. The polyester film for molding according to any one of claims 1 to 4, wherein the film contains 1 to 40 mol% of a branched aliphatic glycol and / or an alicyclic glycol as a copolymer component.   The polyester film for molding according to any one of claims 1 to 5, wherein the branched aliphatic glycol is neopentyl glycol.   The polyester film for molding according to any one of claims 1 to 6, wherein the alicyclic glycol is 1,4-cyclohexanedimethanol.   The polyester film for molding according to any one of claims 1 to 7, wherein the aromatic dicarboxylic acid component is terephthalic acid, naphthalenedicarboxylic acid, or an ester-forming derivative thereof.   The polyester film for molding according to any one of claims 1 to 8, wherein the film has a thickness unevenness of 5.5% or less.   The polyester film for molding according to any one of claims 1 to 9, wherein the film has a heat shrinkage in the longitudinal direction and the width direction at 150 ° C of 6.0% or less.   The polyester film for embossing in any one of Claims 1-10 used for an embossing use.