JP4529072B2 - Polyester film for molding and molded member formed by molding the same - Google Patents

Description

  The present invention relates to a molding polyester film excellent in moldability, transparency, and shape stability (elasticity, strength, heat shrinkage characteristics, thickness unevenness) and a molded member formed by molding the same.

  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.

  Such materials having excellent environmental resistance include copolymer components such as a long-chain linear aliphatic dicarboxylic acid component and / or a long-chain linear aliphatic glycol component having 3 or more carbon atoms. Many studies have been made to improve moldability by using polymerized polyester as a film raw material. However, since the polyester resin is softened by these copolymerization components, it is inferior in form stability (elasticity, strength, heat shrinkage characteristics, thickness variation, etc.) not only at the time of molding but also when actually used as a molded product. There was a drawback. On the other hand, if the composition ratio of the copolymer component is decreased in order to enhance the form stability, the moldability is lowered, and it is difficult to achieve both moldability, strength and elasticity.

For example, a polyester film made of polyester having neopentyl glycol or 1,4-cyclohexanedimethanol as a copolymerization component is known as the copolymer polyester (see, for example, Patent Documents 1 and 2). Since the copolymer polyester films described in these conventional techniques have a thickness of 50 μm or less, film formation is relatively easy.
JP-A-1-252658 Japanese Unexamined Patent Publication No. 1-445699

  However, when the thickness of the film exceeds 50 μm, the copolyester inherently has a tendency of insufficient control of molecular orientation from the viewpoint of stress reduction during stretching and crystallinity, and elasticity. And form stability may be insufficient. Therefore, when using the obtained molded product in a normal temperature atmosphere while maintaining moldability, a polyester film excellent in elasticity and shape stability (heat shrinkage characteristics, thickness unevenness) has been desired.

  Moreover, in order to improve the designability of molded products, printing is often performed on the film surface before the film is molded. Since such a printing layer is often applied to the back side of a molding film, it is desired that the transparency of the film is high from the viewpoint of printing clarity. However, since the conventional film for molding has low transparency, there is a problem that the printed appearance is deteriorated or the backlight is difficult to transmit and the visibility is poor.

In order to deal with such problems, a film in which a copolyester containing an aliphatic dicarboxylic acid having improved moldability at 150 ° C. is biaxially oriented has been proposed (for example, see Patent Document 3). However, the film disclosed in Patent Document 3 tends to have insufficient heat resistance when trying to improve moldability at 150 ° C. Further, the thickness unevenness of the film was insufficient.
Japanese Patent Laid-Open No. 3-67629

Therefore, in order to achieve both moldability and heat resistance, (a) a polyethylene terephthalate film biaxially stretched at a relatively low magnification, or (b) a polyethylene terephthalate blended with polypropylene terephthalate or polybutylene terephthalate, a relatively low magnification. And a biaxially stretched film has been proposed (see, for example, Patent Document 4). However, in this method, if the moldability is improved while maintaining the heat resistance, the transparency of the film tends to decrease.
JP 2001-347565 A

  That is, in the prior art, a film satisfying all of the heat resistance, transparency, and moldability in a well-balanced manner has not been obtained so far.

  In addition, the film disclosed in the prior art does not satisfy the market demand in terms of low-temperature formability, and its improvement has been strongly desired. A conventional polyester film needs to be heated to about 150 ° C. in order to obtain moldability. However, at this temperature, the finished product of the molded product may be hindered due to the dimensional change accompanying the thermal contraction of the film. Moreover, since it is necessary to make the accompanying printing ink and protective film into a heat resistant type, there is a problem that the selection of the material is greatly restricted. On the other hand, if the film can be molded at a relatively low temperature of about 120 ° C., there is an advantage that the problem of the dimensional change rate due to the thermal shrinkage of the film is reduced and the limitation of the material used in combination is reduced. Moreover, the provision of low-temperature formability also leads to energy saving.

  The object of the present invention is to eliminate the above-mentioned problems of the prior art, moldability at the time of heat molding, elasticity and shape stability (heat shrinkage characteristics, thickness unevenness) when used in a room temperature atmosphere as a molded product, and transparency The present invention provides a molding polyester film excellent in molding, in particular, a molding polyester film excellent in moldability at low temperatures and printing sharpness, and a molded member formed by molding it.

That is, the present invention provides a polyester film comprising an aromatic dicarboxylic acid component, ethylene glycol and a copolymerized polyester synthesized from a glycol component comprising branched aliphatic glycol and / or alicyclic glycols, the branch The alicyclic glycol is neopentyl glycol, the alicyclic glycol is 1,4-cyclohexanedimethanol, and the melting point (Tm) of the film is 220 ° C. or higher and lower than 245 ° C., An adhesive modified layer on one side, the film does not contain particles, and the adhesive modified layer includes a resin composed of at least one selected from polyester, polyurethane and / or a copolymer thereof; It contains one or more particles, the ratio of haze H (%) the film to the thickness d ([mu] m) H / d) is less than 0.010, the film is a biaxially stretched film, -15 to-40 ° C. The stretching temperature with respect to the stretching temperature of the first half in the second half of the transverse stretching in the biaxial stretching The stress at 100% elongation in the longitudinal direction and the width direction of the film is 10 MPa or more and less than 180 MPa at 25 ° C. and 1 MPa or more and 100 MPa or less at 100 ° C. A polyester film for molding. Moreover, this invention is a shaping | molding member formed by shape | molding the said polyester film for shaping | molding.

  In the molding polyester film of the present invention, the stress at 100% elongation in the longitudinal direction and the width direction of the film is independently controlled at 25 ° C. and 100 ° C., and the moldability during heating, particularly the moldability at low temperature, In addition, it is excellent in elasticity and shape stability (thickness unevenness, heat shrinkage characteristics) during use as a molded product, and is excellent in transparency when printed on a film because of its excellent transparency.

  The polyester film for molding according to the present invention contains 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 in the base film. . 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).

  The molding polyester film of the present invention using such a copolymerized polyester as a raw material for the base film is excellent in moldability at low temperatures and has a form stability (elasticity) in a normal temperature atmosphere used as a molded product. , Strength, heat shrinkage characteristics, and thickness variation), and is a polyester film particularly suitable for molding applications.

  The above-described features can be expressed by physical properties such that 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 MPa or more and 100 MPa or less at 100 ° C.

  100% elongation stress at 25 ° C. in the longitudinal direction and width direction of the film achieves both form stability (elasticity, strength, thickness variation, thermal 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, in the case of a highly elastic film having a stress at 100% elongation in the atmosphere of 25 ° C. exceeding 180 MPa, the moldability at the time of heat molding, particularly the moldability at a low temperature, is likely to deteriorate.

  From the viewpoint of moldability, it is important that the stress at 100% elongation in the longitudinal direction and the width direction of the film in an atmosphere at 100 ° C. is 1 MPa or more and 100 MPa or less.

  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 small stress at 100% elongation in an atmosphere of 100 ° C. is a desirable direction from the viewpoint of moldability. However, if the stress at 100% elongation in a 100 ° C. atmosphere becomes too small, the stress at 100% elongation at 25 ° C. also decreases, and the elasticity and thickness unevenness in a normal temperature atmosphere deteriorate. It is important to set the lower limit of the stress at 100% elongation of 5 MPa to 5 MPa.

  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 moldability during heat molding.

  From the viewpoint of moldability, the breaking elongation at 100 ° C. is preferably 150% or more, more preferably 170% or more, and particularly preferably 200% or more.

  From the viewpoint of morphological stability (elasticity, strength, 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.

  In addition, it is important from the viewpoint of transparency and print sharpness that the ratio of the haze H (%) to the thickness d (μm) (H / d) of the molding film is less than 0.010. 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 H / d is preferably closer to zero from the viewpoint of transparency and print sharpness. However, if the essential minimum unevenness is not formed on the film surface, the handling properties such as the slipping property and the winding property deteriorate, and the film surface may be damaged or the productivity may deteriorate. Therefore, the lower limit of H / d is preferably 0.001, particularly preferably 0.005. In the case of a translucent nameplate using a backlight or the like, a higher degree of transparency is required. Therefore, the H / d is preferably closer to zero.

  In the molding polyester film of the present invention, the thickness of the base film is preferably 50 to 500 μm from the viewpoints of moldability, stiffness (waist), protection of the printed layer provided on the back surface of the molded film, and design properties. The lower limit value of the thickness of the base film is preferably 60 μm, particularly preferably 70 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 uneven thickness of the polyester film for molding of the present 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% is acceptable.

  Furthermore, the polyester film for molding of the present invention preferably has a heat shrinkage rate of 150% or less in the longitudinal direction and the width direction of 6.0% or less from the viewpoint of reducing printing misalignment.

Hereinafter, preferred embodiments of the present invention will be described in detail.
The polyester in the present invention means a general term for high molecular weight substances constituted by ester bonds.

  In the molding polyester film of the present invention, 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 is used as a base film raw material. Use as 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%.

As the branched aliphatic glycols, neopentyl glycol. Examples of the alicyclic glycol, 1,4-cyclohexanedimethanol.

  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. It is effective to satisfy 1 MPa or more and 100 MPa or less. Furthermore, it is preferable not only because it is excellent in moldability and transparency, but also because it is excellent in heat resistance and improves the adhesion with the adhesiveness modified layer.

  Furthermore, you may use together the following dicarboxylic acid component and / or glycol component as a copolymerization component in the said copolyester as needed, if necessary.

  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 esthetics Forming derivatives, and the like.

  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, a polyfunctional compound such as trimellitic acid, trimesic acid, and trimethylolpropane can be further copolymerized with the copolymerized polyester as necessary.

  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 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.

  The base film in the polyester film for molding of the present invention may use the copolymer polyester as a film raw material as it is, or blend a copolymer polyester having a high ratio of copolymer components with a homopolyester, May be adjusted.

  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 polyester film for shaping | molding 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 220 to 245 ° C. from the viewpoint of heat resistance and moldability . In order to control the melting point of the polyester base film to 220 to 245 ° C., it is preferable to adjust the type and composition of the copolymerization component for the polyester. 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 DSC was measured by using a differential scanning calorimeter (DuPont, V4.OB2000 type) at a temperature of 20 ° C./min.

  The melting point of the polyester base film is more preferably a lower limit of 225 ° C., particularly preferably 230 ° C., from the viewpoint of heat resistance. 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 temperature during molding or use of a molded product.

  The melting point should be higher from the viewpoint of heat resistance, but when a polyethylene terephthalate unit is the main component, it is difficult to ensure transparency with a film having a melting point exceeding 245 ° C. in order to ensure high transparency and flexibility. . Therefore, it is important to lower the melting point by adjusting the ratio of the copolymer component of the copolymer polyester, and the upper limit of the melting point of the copolymer polyester is preferably 245 ° C. Furthermore, when it is necessary to increase transparency, the upper limit of the melting point of the copolyester is set to 240 ° C.

  In order to satisfy all of transparency, flexibility, and heat resistance, for example, it is preferable to melt and mix a high melting point polyester (PET) and a low melting point copolymer polyester. By forming a film using the melt blending method, transparency and high melting point (heat resistance) are achieved while maintaining the same flexibility as when using only copolymer polyester, and only high-melting polyester is used. In this case, it is possible to achieve flexibility and a melting point (heat resistance) having no practical problem while maintaining high transparency.

  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 make the base film contain substantially no particles, but only the thin surface layer contains particles. is there. The thin surface layer can be formed by a coating method or a coextrusion method. By setting it as such a laminated structure, ratio (H / d) of haze H (%) with respect to the thickness d (micrometer) of a film can be made into less than 0.010, maintaining the handling property of a film. Especially, in the case of the coating method, since the adhesiveness with a printing layer can also be improved by using the composition which consists of adhesive modification resin containing particle | grains as an application layer, it is a preferable method.

  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 contaminants derived from foreign substances may be mixed without intentionally adding particles to the base film.

  Examples of the particles contained in the surface layer include inorganic particles and / or organic particles having an average particle size of 0.01 to 10 μm. These inorganic particles and / or organic particles may be used in combination of two or more as required.

  The average particle size of the particles is taken by taking a plurality of photographs of at least 200 particles by electron microscopy, tracing the outline of the particles on an OHP film, and converting the trace image to an equivalent circle diameter with an image analyzer. To calculate.

  When the surface layer contains particles having an average particle diameter exceeding 10 μm, the frequency of forming coarse protrusions on the film surface increases, and the design property 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 surface 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.

  The polyester base film used in the present invention is preferably an unstretched film for applications that require severe moldability. From the viewpoint of heat resistance and dimensional stability, a biaxially stretched polyester film is preferred. Such a biaxial stretching method may be either simultaneous biaxial stretching or sequential biaxial stretching.

  The polyester base film can be made into a laminated structure by a known method using different types of polyester. The laminated 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.

As the method for producing the polyester base film , for example, after drying the polyester as necessary, the polyester base film is supplied to a known melt extruder, extruded from a slit-shaped die into a sheet, and cast by a method such as electrostatic application. is brought into close contact, and cooled and solidified, after obtaining an unstretched sheet, such unstretched sheet is a method of biaxial stretching.

  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, if necessary, 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 polyester film for molding 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-cyclohexanedi When using a copolymer polyester made of methanol, the stretching ratio in the longitudinal direction is 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 MPa or more and 100 MPa or less at 100 ° C. Is preferably 2.8 to 4.0 times, and the draw ratio in the width direction is preferably 3.0 to 4.5 times.

  The stretching conditions for producing the molding 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. specified in the present invention, in the longitudinal stretching step, for example, the stretching temperature is preferably set so that the subsequent lateral stretching can be performed smoothly. 50 to 110 ° C., particularly preferably 80 to 100 ° C., and the draw ratio is preferably 1.5 to 4.0 times, particularly preferably 2.5 to 3.8 times.

  In the transverse stretching, stress at 100% elongation in the longitudinal direction and the width direction is particularly important because it is 10 MPa or more and less than 180 MPa at 25 ° C. and 1 MPa or more and 100 MPa or less 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 be stretched, it is not preferable because the thickness and the stretch ratio are likely to be non-uniform.

  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 copolyester, which is a raw material for the molding polyester film, contains 1 to 40 mol% of a copolymer component, the stretching stress rapidly decreases as the stretching temperature is increased 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. with respect to the preheating temperature in the first half of the transverse stretching, and the stretching temperature is − with respect to the stretching temperature of the first half in the latter half of the transverse stretching. A range of 15 to -40 ° C is preferred. 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 satisfying a stress at 100% elongation in the longitudinal direction and the width direction of 10 MPa to less than 180 MPa at 25 ° C. and 1 MPa 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. The heat treatment temperature and the heat treatment time can be arbitrarily set according to the required level of heat shrinkage. 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. Moreover, it is not preferable to slow the film feeding speed because the 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.

  In the molding polyester film of the present invention, it is preferable to provide an adhesive modification layer as a surface layer on at least one surface of the polyester base film in order to improve the printability. By providing an adhesive reforming layer, inkjet ink, screen printing ink, offset printing ink, electron beam curable ink, sublimation transfer ink, conductive ink, UV curable ink, solvent ink, and vapor deposition layer Adhesiveness to a thin film layer formed by a sputtering method is improved, and the finishing quality and durability of printing can be improved.

  As a method of providing an adhesive modified layer on the surface of the base film, a method of applying a coating liquid containing an adhesive modified resin to the surface of the base film, or a base film by coextrusion of the adhesive modified resin And a method of laminating them. In particular, the former method of applying the coating solution containing the adhesive modification resin to the surface of the base film is from the viewpoint of adhesion between the adhesion modified layer and the printing ink layer or other functional layer. Is the most effective method.

  Furthermore, in order to further improve the adhesion between the base film and the adhesive modified layer, the surface of the base film may be surface-treated in advance, and the adhesive modified layer may be provided on the surface-treated surface. Examples of the surface treatment method include: (1) a method using irradiation with active energy rays such as corona discharge treatment, plasma discharge treatment, ultraviolet (UV) irradiation treatment, radiation (EB) irradiation treatment, (2) flame treatment, (3 ) Vapor deposit methods such as PVD and CVD.

As the resin constituting the adhesion modifying layer, a resin composed of at least one selected from polyester, polyurethane Contact and / or copolymers thereof. 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.). make.

  Examples of the polyester-based resin constituting the adhesion modified layer include 0.5 to 15.0 mol% of a sulfonic acid metal base-containing dicarboxylic acid and 85.0 to 99.5 dicarboxylic acid not containing a sulfonic acid metal base. Examples thereof include water-insoluble polyester copolymers obtained by reacting two kinds of dicarboxylic acids with a mol% with a polyol component.

  Examples of the sulfonic acid metal base-containing dicarboxylic acid include metal salts such as 5-sulfoisophthalic acid, 4-sulfoterephthalic acid, 4-sulfonaphthalene-2,7-dicarboxylic acid, and 5 [4-sulfophenoxy] isophthalic acid. Particularly preferred are 5-sodium sulfoisophthalic acid and 4-sodium sulfoterephthalic acid.

  It is preferable that these sulfonic-acid metal base containing dicarboxylic acid components are 0.5-15.0 mol% with respect to all the dicarboxylic acid components. The composition ratio of the sulfonic acid metal base-containing dicarboxylic acid component to the total dicarboxylic acid component is particularly preferably a lower limit of 2.0 mol% from the viewpoint of dispersibility in water, and an upper limit of 10 from the viewpoint of water resistance. Particularly preferred is 0.0 mol%. When the composition ratio is less than 0.5 mol%, the dispersibility in water tends to be remarkably lowered. On the other hand, when the composition ratio exceeds 15.0 mol%, the water dispersibility is improved, but the water resistance of the polyester copolymer is remarkably lowered.

  Although the dispersibility with respect to the water of a polyester copolymer changes with kinds, compounding ratios, etc. of a copolymer component, as long as the dispersibility with respect to water is not impaired, the said sulfonic-acid metal base containing dicarboxylic acid component is preferable.

  As the dicarboxylic acid component not containing a sulfonic acid metal base, aromatic, alicyclic and aliphatic dicarboxylic acids can be used. Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, orthophthalic acid, and 2,6-naphthalenedicarboxylic acid. These aromatic dicarboxylic acid components are preferably 40 mol% or more of the total dicarboxylic acid components. When the aromatic dicarboxylic acid component is less than 40 mol% with respect to the total dicarboxylic acid component, the mechanical strength and water resistance of the polyester copolymer are likely to decrease.

  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 above two types 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.

  Furthermore, as a polyester-based resin constituting the adhesive modification 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, And a resin obtained by graft-modifying a water-insoluble polyester copolymer obtained by reacting the two types of dicarboxylic acid components with a polyol component with an unsaturated bond-containing monomer.

  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. As aromatic dicarboxylic acids, 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 above two types 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.

  As the unsaturated group-containing monomer used for graft-modifying the above unsaturated polyester, those which are polymerized by radicals are preferred. 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 , Methacrylic acid esters (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 pyrrolide , Styrene, alpha-methyl styrene, t- butyl styrene, vinyl toluene, maleic anhydride.

  The above 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.

  Examples of the urethane-based resin constituting the adhesive property modification layer include a heat-reactive water-soluble urethane in which a terminal isocyanate group is blocked with a hydrophilic group. As the isocyanate group blocking agent, a large number of compounds such as bisulfites and phenols, alcohols, lactams, oximes, and active methylene compounds containing a sulfone group can be applied.

  The blocked isocyanate group hydrophilizes or water-solubilizes the urethane prepolymer, and the blocking agent is removed from the molecular chain by drying or heat setting during film production. That is, when thermal energy is applied to the polymer containing the blocked isocyanate group, the blocking agent is detached from the isocyanate group, and the polymer is self-crosslinked. The polymer at the time of preparing the coating solution is poor in water resistance because it is hydrophilic, but when the thermal reaction is completed by coating, drying, and heat setting, the hydrophilic group of the urethane polymer is detached, so the water resistance is good. A coating film is obtained.

  Among the above blocking agents, bisulfites are preferred as those having a suitable heat treatment temperature and heat treatment time and widely used industrially. The urethane prepolymer used in the urethane polymer includes (1) a compound having two or more active hydrogen atoms in the molecule and a molecular weight of 200 to 20,000, and (2) two in the molecule. Examples include organic polyisocyanates having the above isocyanate groups and (3) compounds having terminal isocyanate groups obtained by reacting a chain extender having at least two active hydrogen atoms in the molecule.

  Generally known as the compound (1) above are those containing two or more hydroxyl groups, carboxyl groups, amino groups, or mercapto groups in the terminal or molecule. Of these, polyether polyols, polyester polyols, polyether ester polyols, and the like are particularly preferable.

  Polyether polyols include, for example, alkylene oxides such as ethylene oxide and propylene oxide, or compounds obtained by polymerizing styrene oxide and epichlorohydrin, and their random copolymerization, block copolymerization, or addition polymerization to polyhydric alcohols. There are compounds obtained.

  Examples of the polyester polyol and the polyether ester polyol mainly include linear or branched compounds. Saturated and unsaturated such as succinic acid, adipic acid, phthalic acid, or their anhydrides, and ethylene glycol, diethylene glycol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, and trimethylolpropane Can be obtained by a condensation reaction between the above alcohols, polyalkylene ether glycols such as relatively low molecular weight polyethylene glycols and polypropylene glycols, and mixtures thereof.

  Furthermore, polyesters obtained from lactones and hydroxy acids can be used as polyester polyols, and polyether esters obtained by adding ethylene oxide or propylene oxide to polyesters prepared in advance can be used as polyether ester polyols. Can do.

  Examples of the organic polyisocyanate (2) include (a) isomers of toluylene diisocyanate, (b) aromatic diisocyanates such as 4,4-diphenylmethane diisocyanate, and (c) aromatic aliphatics such as xylylene diisocyanate. Diisocyanates, (d) alicyclic diisocyanates such as isophorone diisocyanate and 4,4-dicyclohexylmethane diisocyanate, (e) aliphatic diisocyanates such as hexamethylene diisocyanate and 2,2,4-trimethylhexamethylene diisocyanate, (f ) Polyisocyanates obtained by adding one or more of these compounds with trimethylolpropane or the like in advance.

  The chain extender having at least two active hydrogens in (3) above includes (a) glycols such as ethylene glycol, diethylene glycol, 1,4-butanediol, and 1,6-hexanediol, and (b) glycerin. Polyhydric alcohols such as trimethylolpropane and pentaerythritol, (c) diamines such as ethylenediamine, hexamethylenediamine and piperazine, (d) amino alcohols such as monoethanolamine and diethanolamine, (e) thio And thiodiglycols such as diethylene glycol, and (f) water.

  In addition, a catalyst compound having an effect of promoting the reaction of each crosslinking agent or curing agent can be appropriately added, and various known techniques can be used for this purpose.

  The self-crosslinking resin can be selected from resins that can be used as the crosslinking agent or curing agent. In particular, resins such as water-soluble or water-dispersible methylol melamine resin, urea formalin resin, polyether added with a polyfunctional blocked isocyanate group, polyester, polyether urethane, polyether ester and the like are suitable. Moreover, a curing catalyst can be used as needed.

  Among the resin compositions constituting the adhesive modified layer, a water-soluble polyurethane system having a water-insoluble and water-dispersible polyester resin containing a sulfone group in the molecule and at least one blocked isocyanate in the molecule Laminated polyester film provided with an adhesive modified layer composed of an adhesive modified resin mixed with resin is excellent in heat resistance when it is heat-molded. In particular, it is particularly preferable because the adhesion to printing inks such as ultraviolet (UV) curable inks and oxidative polymerization inks can be greatly improved.

  In this case, the content of the water-insoluble and water-dispersible polyester resin (A) and the water-soluble polyurethane resin (B) is (A) / (B) = 90/10 to 10/90 in mass ratio. It is preferable that (A) / (B) = 80/20 to 20/80 is particularly preferable in terms of mass ratio.

  As a method for providing the adhesive modified layer, as described above, there is a method in which a coating liquid containing an adhesive modified resin composition mainly composed of an adhesive modified resin is applied to the surface of the polyester base film. 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 adhesion-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 a step of applying to a polyester film, a method of applying in advance to the surface of an unstretched film, a method of applying to a film surface after orienting in a uniaxial direction, and a method of orienting to a perpendicular direction, and then applying to a film surface after biaxial orientation Any method such as a method 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.

  The molding polyester film of the present invention is particularly preferably used for molding applications. The polyester film for molding is used by applying heat or pressure to deform it. Examples of the molding means include pressure molding, press molding, laminate molding, vacuum molding, vacuum / pressure molding, in-mold molding, drawing molding, and bending molding. The molded body thus molded is suitable as a molded member for home appliance nameplates, automobile nameplates, dummy cans, building materials, decorative plates, decorative steel plates, transfer sheets, and the like.

  Hereinafter, the present invention will be described in detail by way of examples. The film properties obtained in each example were measured and evaluated by the following methods.

(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), minimum value (dmin), and 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 kg. 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, under a constant tension of 5 g (tension in the length direction), the interval B between the two marks is read with a gold finger in units of 0.25 mm. 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) Formability After printing on the film, it was contact-heated with a hot plate at 140 ° C for 4 seconds, and then press-molded at a mold temperature of 70 ° C and a holding time of 5 seconds. The shape of the mold was a cup shape, the opening portion had a diameter of 50 mm, the bottom portion had a diameter of 40 mm, the depth was 20 mm, and all corners were rounded with a radius of 1 mm. After press molding, printing misalignment was measured, and the molding state was visually observed, and ranked according to the following criteria. In addition, (double-circle) and (circle) were set as the pass, and x was set as the disqualification.

A: (i) Molded product is not torn, (ii) Corner radius of curvature is 2 mm or less, printing deviation is 0.1 mm or less, and (iii) No appearance defect corresponding to x: (I) The molded product is not torn, (ii) The corner radius of curvature is more than 2mm and 3mm or less, or the printing deviation is more than 0.1mm and 0.2mm or less. There is no appearance defect and there is no problem in practical use ×: The molded product is torn, or even if it is not torn, it falls under any of the following items (i) to (iv)
(I) Corner radius of curvature exceeds 3mm
(ii) A large bag with a bad appearance
(iii) The film is whitened and the transparency is lowered
(iv) Print misalignment exceeding 0.2 mm

(8) Print quality 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. Evaluation of printing quality was made by visually judging the printing appearance such as the following clear feeling, printing suitability, printing misalignment and the like through the film from the back side, not from the printing side. Judgment criteria were ◯ when there was no problem from all viewpoints, and x when there was a problem at least at one point.
a. Clear feeling: The printed design is not blocked by the base film or coating layer.
It must be clear.
b. Printability: Color unevenness and missing due to poor transfer of printing ink c. Print misalignment: The misalignment of the print cannot be discerned visually.

Example 1
(Coating solution adjustment)
Water-soluble urethane resin (1st) with a copolymerized polyester resin (Toyobo Co., Ltd., Bironal MD-1250) 3.15% by mass in isopropanol 40% by weight aqueous solution and terminal isocyanate groups blocked with hydrophilic groups The coating solution was adjusted so that 5.85% by mass of Elastolon H-3, manufactured by Kogyo Seiyaku Co., Ltd., and 12.5% by mass of silica particles with an average particle size of 0.45 μm were contained in the total resin. did. 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)
Copolymer polyester chip 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. Each of (A) and a polyethylene terephthalate chip (B) having an intrinsic viscosity of 0.69 dl / g was dried. Furthermore, the chip (A) and the chip (B) were mixed so as to have a mass ratio of 25:75. Subsequently, these chip mixtures were melt-extruded from the slit of the T die at 280 ° C. with an extruder, rapidly cooled and solidified on a chill roll having a surface temperature of 40 ° C., and at the same time, the amorphous mixture was adhered to the chill roll using an electrostatic application method. A stretched sheet was obtained.

  The obtained unstretched sheet was stretched 3.5 times at 92 ° C. in the longitudinal direction between the heating roll and the cooling roll. Subsequently, the said coating liquid was apply | coated to the single side | surface of a uniaxially stretched film so that the thickness of the resin solid content before extending | stretching might be set to 0.9 micrometer by the reverse kiss coating method. The laminated film having the coating layer is dried and led 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 7% in the transverse direction. While relaxing, heat treatment was performed at 205 ° C. to obtain a laminated biaxially stretched polyester film having a thickness of 188 μm. The characteristics and evaluation results of the obtained film are shown in Table 1.

Comparative Example 1
Containing 400 ppm of amorphous silica with an average particle size of 1.5 μm as a constituent component, 100 mol% of terephthalic acid unit as aromatic dicarboxylic acid component, 85 mol% of ethylene glycol unit and 15 mol% of neopentyl glycol unit as diol component The copolyester having an intrinsic viscosity of 0.69 dl / g was pre-crystallized and then dried. Next, it is melt-extruded at 280 ° C. using an extruder having a T die, rapidly cooled and solidified on a chill roll having a surface temperature of 40 ° C., and at the same time, an amorphous unstretched sheet is obtained while closely contacting the chill roll using an electrostatic application method. It was.

  The obtained unstretched sheet was stretched 3.5 times at 92 ° C. in the longitudinal direction between the heating roll and the cooling roll. Next, the uniaxially stretched film is guided to a tenter, preheated at 100 ° C. for 15 seconds, and the first half of the transverse stretching is stretched 3.6 times at 115 ° C. and the latter half is 95 ° C., while relaxing by 7% in the transverse direction. Heat treatment was performed at 205 ° C. to obtain a biaxially stretched polyester film having a thickness of 188 μm. The characteristics and evaluation results of the obtained film are shown in Table 1.

Comparative Example 2
In Example 1, a laminated biaxially stretched polyester film was obtained in the same manner as in Example 1 except that the content of amorphous silica in the coating solution was changed from 12.5% by mass to 30% by mass. Table 1 shows the properties and evaluation results of the film.

Comparative Example 3
In Example 1, as raw materials for the film, the aromatic dicarboxylic acid component is 100 mol% terephthalic acid unit, the diol component is ethylene glycol unit 85 mol% and neopentylglycol unit 15 mol%, and the average particle size is A laminated biaxially stretched polyester film was obtained in the same manner as in Example 1 except that a copolymer polyester containing 400 ppm of 1.5 μm amorphous silica and having an intrinsic viscosity of 0.69 dl / g was used. The properties and evaluation results of the obtained film are shown in Table 1.

Comparative Example 4
Polyethylene terephthalate having an intrinsic viscosity of 0.69 dl / g and comprising 100 mol% of terephthalic acid units as the aromatic dicarboxylic acid component and 100 mol% of ethylene glycol units as the diol component was pre-crystallized and then dried. Next, it is melt-extruded at 280 ° C. using an extruder having a T die, rapidly cooled and solidified on a chill roll having a surface temperature of 40 ° C., and at the same time, an amorphous unstretched sheet is obtained while closely contacting the chill roll using an electrostatic application method. It was.

  The obtained unstretched sheet was stretched 3.7 times at 97 ° C. in the longitudinal direction between the heating roll and the cooling roll. Subsequently, the said coating liquid was apply | coated to the single side | surface of a uniaxially stretched film so that the thickness of resin solid content before extending | stretching might be set to 0.9 micrometer by the reverse kiss coating method. 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 120 ° C., the latter half is stretched 4.0 times at 120 ° C., and the film is relaxed by 10% in the transverse direction. Then, heat treatment was performed at 230 ° C. to obtain a laminated biaxially stretched polyester film having a thickness of 188 μm. The characteristics and evaluation results of the obtained film are shown in Table 1.

Example 2
Copolymerized polyester chip 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 The polyethylene terephthalate chip (B) was mixed so as to have a mass ratio of 30:70 and dried. Next, it is melt-extruded at 280 ° C. using an extruder having a T die, rapidly cooled and solidified on a chill roll having a surface temperature of 40 ° C., and at the same time, an amorphous unstretched sheet is obtained while closely contacting the chill roll using an electrostatic application method. It was.

  The obtained unstretched sheet was stretched 3.0 times at 85 ° C. in the longitudinal direction between the heating roll and the cooling roll. Subsequently, the said coating liquid was apply | coated to the single side | surface of a uniaxially stretched film so that the thickness of resin solid content before extending | stretching might be set to 0.9 micrometer by the reverse kiss coating method. 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%. Then, heat treatment was performed at 205 ° C. to obtain a laminated biaxially stretched polyester film having a thickness of 188 μm. The characteristics and evaluation results of the obtained film are shown in Table 1.

Example 3
In Example 1, after the copolymerized polyester chip (A) and the polyethylene terephthalate chip (B) having an intrinsic viscosity of 0.69 dl / g were dried, the mass ratio was 33:67. A laminated biaxially stretched polyester film was obtained in the same manner as in Example 1 except for mixing.

Comparative Example 5
Intrinsic viscosity with a composition of 90 mol% terephthalic acid unit as dicarboxylic acid component, 10 mol% adipic acid and 100 mol% ethylene glycol unit as diol component, containing 800 ppm amorphous silica with an average particle size of 1.4 μm A laminated biaxially stretched polyester film was obtained in the same manner as in Example 1 except that a copolyester having a weight of 0.71 dl / g was used.

Example 4
(Coating solution adjustment)
The dicarboxylic acid component has a composition of 50 mol% terephthalic acid unit, 45 mol% isophthalic acid unit, 5 mol% fumaric acid, 50 mol% ethylene glycol unit and 50 mol% neopentyl glycol as the diol component, and has a reduced viscosity of 0. .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 Example 1, a laminated biaxial polyester film was obtained in the same manner as in Example 1 except that the graft-modified polyester resin dispersion obtained above was used as the coating solution. The properties and evaluation results of the obtained film are shown in Table 1.

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

Example 5
The laminated biaxially stretched polyester film obtained in Example 1 was press-molded at a mold temperature of 100 ° C. to produce a nameplate for a switch having an indentation depth of 2.0 mm. The appearance of the obtained nameplate was good.

  The polyester film for molding of the present invention is excellent in moldability at low temperature, elasticity and shape stability (thickness unevenness, heat shrinkage characteristics) at the time of use as a molded product, and print sharpness. In addition, various printing decoration methods such as letterpress printing, intaglio printing, planographic printing, screen printing, offset printing, gravure printing, ink jet printing, flexographic printing, and textile printing, transfer, painting, painting, etc. A three-dimensional decoration method in which designs such as printed layers and design layers are applied by decoration methods such as coating, vapor deposition, sputtering, CVD, and lamination, and then molded by various molding methods such as mold molding, pressure molding, and vacuum molding. Suitable and excellent in-mold moldability and emboss moldability. Therefore, it is suitable as a member for nameplates or building materials for home appliances and automobiles.

Claims (8)

A polyester film comprising a copolymer polyester synthesized from an aromatic dicarboxylic acid component of a polyester base film and ethylene glycol and a glycol component containing a branched aliphatic glycol and / or an alicyclic glycol,
The branched aliphatic glycol is neopentyl glycol;
The alicyclic glycol is 1,4-cyclohexanedimethanol;
The melting point (Tm) of the film is 220 ° C. or higher and lower than 245 ° C.,
Having an adhesive modification layer on at least one side of the film;
The film does not contain particles,
The adhesive modification layer contains at least one resin selected from polyester, polyurethane and / or copolymers thereof, and one or more kinds of particles .
The film has a ratio (H / d) of haze H (%) to thickness d (μm) of less than 0.010,
The film is a biaxially stretched film, and is obtained by performing the stretching temperature in the range of −15 to −40 ° C. with respect to the stretching temperature of the first half in the latter half of the transverse stretching in the biaxial stretching. ,
And the 100% elongation stress in the longitudinal direction and the width direction of the film is 10 MPa or more and less than 180 MPa at 25 ° C. and 1 MPa or more and 100 MPa or less at 100 ° C. Molding the polyester film of claim 1, wherein the copolymerized polyester is amorphous polyester. The polyester film for molding according to claim 1 or 2 , 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 3 , wherein the film has a heat shrinkage rate of not more than 6.0% in a longitudinal direction and a width direction at 150 ° C. The polyester film for molding according to any one of claims 1 to 4, wherein the film comprises a polyester obtained by blending a copolyester with a homopolyester. In the biaxial stretching, the preheating temperature of the transverse stretching is 90 to 120 ° C, and the stretching temperature of the first half of the transverse stretching is +5 to 25 ° C with respect to the preheating temperature. The polyester film for molding according to crab. The polyester film for molding according to any one of claims 1 to 6, wherein the film has a thickness of 60 to 500 µm. Molded member obtained by molding the molding polyester film according to any one of claims 1-7.