JPWO2007094441A1 - Biaxially oriented polyester film for molding - Google Patents

Abstract

An object of the present invention is to provide a biaxially oriented polyester film for molding that exhibits excellent releasability and non-adhesiveness and also has a molding process. A coating layer having a surface free energy of 15 to 35 mN / m is laminated on at least one surface of a polyester film, the center line average roughness of the coating layer is 1 to 50 nm, and the film is arbitrarily formed. A biaxially oriented polyester film for molding, in which the center line average roughness of the coating layer after extending twice in the direction is 1 to 50 nm. [Selection figure] None

Description

  The present invention relates to a biaxially oriented polyester film for molding, and exhibits excellent releasability and non-adhesiveness even after repeated use, high-temperature heat treatment, use after retort treatment, use in a water atmosphere, and small variation. The present invention relates to a film that exhibits stable performance and a method for producing the same. In addition, the present invention relates to a film that does not change its surface state before and after being molded and exhibits excellent releasability and non-adhesiveness even after molding. For this reason, when it is pasted to a base material, etc., when it is molded or the film itself is molded into a container, etc., the contents are excellent in releasability and non-adhesiveness. Is suitable for food containers. In particular, a form used for the inner surface of a metal can which is molded after being laminated on a metal plate such as steel or aluminum is a very preferable aspect.

  Polyester films are used in a wide range of fields such as industrial materials, magnetic recording materials, optical materials, information materials, and packaging materials because of their excellent mechanical strength, thermal characteristics, humidity characteristics, and many other excellent characteristics.

In recent years, polyester films have been widely used as containers or the like by taking advantage of their excellent characteristics and forming them after being bonded to a base material, or forming polyester films themselves. However, polyester is poor in releasability from its molecular skeleton, and when used on the inner surface of a container or the like, there is a problem that the content adheres. In order to impart the non-adhesiveness of the contents, a polyester film added with wax has been proposed (for example, Patent Document 1). However, in this proposal, since wax is added at the time of polyester polymerization or wax master pellets are used, the wax is not efficiently dispersed on the surface, and the non-adhesive effect is small. In addition, a film in which a release property is imparted by coating a polyester film surface with a silicone resin, a fluorine-based resin, or the like has been proposed (for example, Patent Document 2). However, since it is inferior in moldability, it cannot be used for molding processing applications, and when it is subjected to retort treatment, there is a problem that the performance is remarkably reduced, and when the molding processing is performed, the surface is roughened. There was a problem that defects such as dents would occur.
JP 2001-220453 A Japanese Patent Laid-Open No. 2004-115566

  An object of the present invention is to eliminate the above-described problems of the prior art, and to provide a biaxially oriented polyester film for molding that exhibits excellent non-adhesiveness even after high-temperature heat treatment and retort treatment and also has a molding process. That is.

In order to solve the above problems, the biaxially oriented polyester film for molding of the present invention has the following configuration.
(1) A coating layer having a surface free energy of 15 to 35 mN / m is laminated on at least one surface of the polyester film,
The center line average roughness of the coating layer is 1 to 50 nm,
And the biaxially-oriented polyester film for shaping | molding whose centerline average roughness of the coating layer after extending | stretching a film twice in arbitrary directions at 23 degreeC is 1-50 nm.
(2) The contact angle of the coating layer with water is 90 to 120 °,
The biaxially oriented polyester film for molding according to (1), wherein the contact angle with water after heat treatment at 180 ° C. for 120 minutes is 90 to 120 °.
(3) The center line average roughness of the coating layer after stretching 1.5 times in any one direction of the film and in a direction perpendicular to the direction at 200 ° C. is 1 to 50 nm (1) or (2 The biaxially oriented polyester film for molding described in 1.).
(4) The biaxial molding according to any one of (1) to (3), wherein the surface free energy of the coating layer after the film is stretched twice in any direction at 23 ° C. is 15 to 35 mN / m. Oriented polyester film.
(5) The biaxially oriented polyester film for molding according to any one of (1) to (4), wherein the coating layer uses a silicone compound.
(6) The biaxially oriented polyester film for molding according to (5), wherein the silicone compound comprises a main agent and a crosslinking agent.
(7) The biaxially oriented polyester film for molding according to (6), wherein the silicone compound is an addition reaction of an organopolysiloxane containing an alkenyl group as a main component and a hydrogen polysiloxane as a crosslinking agent.
(8) The biaxially oriented polyester film for molding according to any one of (1) to (7), wherein the coating layer has a thickness of 0.01 to 3 μm.
(9) Molding according to any one of (1) to (8), wherein the contact angle between the coating layer and water is 90 to 120 ° when the retort treatment is performed at 125 ° C. and 0.12 MPa for 90 minutes. Biaxially oriented polyester film.
(10) The biaxially oriented polyester film for molding according to any one of (1) to (9), which has a melting point of 246 to 270 ° C.
(11) The 100% elongation stress F100 _A value in an arbitrary direction (A direction) of the film at 100 ° C. and the 100% elongation stress F100 _B value in a direction orthogonal to the direction (B direction) are 20 to 20 respectively. The biaxially oriented polyester film for molding according to any one of (1) to (10), which is 110 MPa.
(12) The biaxially oriented polyester film for molding according to any one of (1) to (11), which is used for metal plate bonding.
(13) The biaxially oriented polyester film for molding according to any one of (1) to (12), which is used for container molding.
(14) A method for producing a biaxially oriented polyester film for molding according to (1), wherein the emulsion surface coating energy is coated after the surface free energy of the coating surface is 47 mN / m or more. A method for producing a biaxially oriented polyester film for molding.

  Since the biaxially oriented polyester film for molding of the present invention has a large contact angle with water and low surface free energy, it is excellent in releasability and non-adhesiveness and can be used for various applications. In addition, there is no change in surface roughness after molding, and a high water contact angle is exhibited even after high-temperature heat treatment. Therefore, excellent mold release and non-adhesiveness are maintained even after film formation or heat treatment. be able to. Furthermore, it is preferably excellent in moldability and has a high water contact angle even after retort treatment, so that it can be used for container forming applications such as foods.

  The biaxially oriented polyester film for molding of the present invention is formed by laminating a coating layer on at least one surface of a polyester film. By laminating the coating layer, the characteristics of the film surface can be improved efficiently.

  The method for laminating the coating layer in the present invention is not particularly limited, and an extrusion laminating method and a melt coating method may be used. However, for example, gravure coating, reverse coating, spray coating, kissing can be performed at high speed. A method of laminating by coating, die coating or metering bar coating is preferably used. Moreover, it is also possible to laminate a coating layer in-line, and it is preferable to apply after longitudinal stretching in the middle of the film production process by a normal sequential biaxial stretching method because drying, heat treatment and transverse stretching are performed in a tenter.

  In the present invention, before the coating of the coating material, the film is subjected to surface activation treatment such as corona discharge treatment, ozone treatment, ultraviolet treatment, sand mat processing treatment, chemical treatment, etc. Preferably it is 47 mN / m or more, more preferably 50 mN / m or more, since the adhesion between the coating layer and the polyester film can be improved and the coating defects can be eliminated. By improving the adhesion between the coating layer and the polyester film, the heat resistance, water resistance, and retort resistance of the coating layer can be improved.

  In the present invention, the surface free energy of the coating layer is required to be 15 to 35 mN / m from the viewpoint of releasability, non-adhesiveness, and handleability. When the surface free energy of the coating layer is greater than 35 mN / m, the release property and non-adhesiveness are poor. On the other hand, if the surface free energy is less than 15 mN / m, the rollability and processability of the film are inferior, and the fulcrum in the nip and molding process in the laminate is not stable. A more preferable range of the surface free energy is 17 to 33 mN / m, and most preferably 20 to 30 mN / m.

  In addition, the biaxially oriented polyester film for molding of the present invention requires that the surface free energy of the coating layer after stretching the film twice in an arbitrary direction at 23 ° C. is 15 to 35 mN / m. . If the surface free energy of the coating layer after stretching the film twice in any direction is 15 to 35 mN / m, the film is bonded to the base material and then subjected to molding or the film itself is molded. Later, excellent properties can be exhibited in releasability and non-adhesiveness. The more preferable range of the surface free energy after extending the film twice in an arbitrary direction is 17 to 33 mN / m, and most preferably 20 to 30 mN / m.

  Moreover, in this invention, it is preferable that the contact angle with the water of a coating layer is 90-120 degrees at the point of mold release property, non-adhesiveness, and handleability. If the contact angle with water is in the above range, releasability, non-adhesiveness, and handleability can be compatible. If the contact angle with water is less than 90 °, the releasability and non-adhesiveness are poor. If the contact angle with water is greater than 120 °, the film winding property and workability may be inferior, and the nip in the laminate or the fulcrum in the forming process may not be stable. A more preferable range of the contact angle of the coating layer with water is 95 to 120 °, and most preferably 97 to 120 °.

  In the present invention, it is preferable that the contact angle between the coating layer and water is 90 to 120 ° when heat treatment is performed at 180 ° C. for 120 minutes. If the contact angle between the coating layer and water after heat treatment at 180 ° C. for 120 minutes is 90 to 120 °, it can be used for molding and further food containers even after heat molding and dry heat sterilization. can do.

  In order to set the contact angle after heat treatment at 180 ° C. for 120 minutes within the above range, a coating compound with high heat resistance is used, the adhesion between the polyester film and the coating compound is improved, or the coating compound is crosslinked. Is preferably introduced.

  The more preferable range of the contact angle with water after heat treatment at 180 ° C. for 120 minutes is 95 to 120 °, and most preferably 97 to 120 °.

  In order to make the surface free energy of the coating layer and the contact angle with water within the above ranges, it is effective to include a water-repellent compound in the coating layer. The composition constituting the coating layer may be composed only of the water repellent compound, but may contain a resin, a solvent, water, a metal and the like as long as the characteristics of the present invention are not impaired. By uniformly dispersing the water repellent compound on the surface of the coating layer, the water contact angle and the surface free energy can be within the above ranges.

  Examples of water repellent compounds include straight silicones such as dimethyl silicone, methyl phenyl silicone, and methyl hydrogen silicone, amino groups, epoxy groups, carboxyl groups, carbinol groups, alkyl groups, polyether groups, etc. at the side chains and / or terminals. Silicone compounds such as modified silicones with organic groups introduced, natural waxes such as whale wax, beeswax, lanolin, carnauba wax, canderia wax, montan wax, rice wax, stearyl stearate, paraffin wax, microcrystalline wax, oxidized wax , Wax compounds such as ester wax, synthetic waxes such as low molecular weight polyethylene, polytetrafluoroethylene, tetrafluoroethylene / perfluoroalkoxyethylene copolymer Body, but such a fluorine compound such as tetrafluoroethylene / ethylene copolymers, handling, economics, from the viewpoints of heat resistance, water repellency, silicone compounds are preferably used.

  In the present invention, the silicone compound that is preferably used in the coating layer is preferably composed of a main agent and a crosslinking agent in terms of adhesion to a polyester film, water resistance, heat resistance, and the like. As the main agent, the above-described silicone compound can be used. The main agent here refers to a component that is contained most in the silicone compound on the basis of mass.

The crosslinking agent is not particularly limited as long as it undergoes a crosslinking reaction with the main agent. For example, the main agent: alkenyl group-containing / crosslinking agent: Si-H bond-containing, main agent: silanol group or alkoxy group-containing / crosslinking agent. : Hydroxyl group-containing, such as alkoxy group and acyloxy group, main component: hydroxyl group-containing / crosslinking agent: isocyanate group-containing combinations, etc. are preferably used. Among these, in terms of adhesion, heat resistance, water resistance, and retort resistance, an organopolysiloxane containing an alkenyl group as a main agent and a silicone compound obtained by addition reaction using hydrogen polysiloxane as a crosslinking agent are preferably used. Is done. In this case, as an addition reaction catalyst, rhodium such as platinum compounds such as chloroplatinic acid, alcohol-modified chloroplatinic acid, chloroplatinic acid-vinylsiloxane complex, and RhCl (Ph ₃ P) ₃ described in JP-A-4-352793. It is preferable to add a compound.

  A preferable blending amount of the main agent and the cross-linking agent is 0.05 to 20 parts by weight with respect to the main agent as 100 parts by weight. More preferably, it is 0.1 to 15 parts by weight, and most preferably 0.15 to 10 parts by weight. The addition amount of the addition reaction catalyst is preferably 0.0001 to 1 part by weight with respect to 100 parts by weight of the main agent from the viewpoint of economy and catalytic effect, and 0.0002 to 0.8 part by weight. More preferably, 0.0005 to 0.5 part by weight is most preferable.

  Moreover, in this invention, when forming a coating layer, it is preferable to produce the coating composition containing the said water-repellent compound, and to form a coating layer using this. The form of the coating composition is not particularly limited, and examples thereof include an oil type, an emulsion type, a solution type, a baking type, a paste type, and a spray type. As used herein, the coating composition refers to a raw material composition used when a coating layer is applied, and may include a component that volatilizes in a drying step or the like because of the composition before coating. A preferable coating composition includes an emulsion type in terms of workability, economy, handling, and the like. The emulsion type coating composition can be used by diluting with water depending on the applicability. In order to further improve coating properties, polyvinyl alcohol polymers or derivatives thereof, cellulose conductors such as carboxymethylcellulose and hydroxyethylcellulose, starches such as etherified starch and dextrin, polar groups such as polyvinylpyrrolidone and sulfoisophthalic acid As a thickener, water-soluble polymer compounds such as vinyl polymers such as copolymer polyesters, polyhydroxyethyl methacrylate or copolymers thereof, acrylic polymers, urethane polymers, ether polymers, etc. It can also be used together. From the viewpoint of applicability, the preferred viscosity range is 5 to 1000 mPa · s, more preferably 10 to 800 mPa · s, and most preferably 20 to 500 mPa · s. In addition, the value of the viscosity here is measured based on JIS K-7117, and is a thing at 23 degreeC.

  Further, in order to reduce the surface free energy of the coating composition and improve the coating property to the film, an organic solvent such as methanol, ethanol, isopropyl alcohol, benzene, hexane, heptane, acetone may be added and used. . From the viewpoint of applicability and handleability, the surface free energy of the coating composition is preferably 30 to 60 mN / m. If the surface free energy of the coating composition is greater than 60 mN / m, the coatability may be inferior. On the other hand, if the surface free energy is to be less than 30 mN / m, it is necessary to add a large amount of an organic solvent having a small surface free energy, which is not preferable because the handling property is lowered. A more preferable range of the surface free energy of the coating composition is 30 to 55 mN / m, and most preferably 35 to 50 mN / m.

  When the viscosity of the coating composition is in the preferred range, it is excellent in applicability even if the surface free energy is high. Conversely, when the surface free energy of the coating agent is in the preferred range, it is excellent in applicability even if the viscosity is low. The viscosity and surface free energy can be appropriately selected and adjusted according to the explosion-proof equipment of the coating process, the storage environment of the coating composition, and the like. By increasing the coating property, the effect of the water-repellent compound is enhanced, and the contact angle with water and the surface free energy are easily within the above ranges, which is very preferable.

  When a water-soluble polymer compound or an organic solvent is added to form a coating composition, the preferred concentration of the water-repellent compound is the coating composition in terms of uniform dispersibility, applicability, releasability, and non-adhesiveness. The total product is 100% by mass, 0.1 to 60% by mass, more preferably 0.5 to 50% by mass, and most preferably 1 to 40% by mass. When the water repellent compound concentration is high, the coatability and uniform dispersibility may be inferior. Moreover, since it becomes inferior to mold release property and non-adhesiveness when a water-repellent compound density | concentration becomes low, it is unpreferable.

  By making the concentration of the water repellent compound within the above preferable range, it can be efficiently dispersed on the surface of the coating layer to achieve a contact angle with water of 90 to 120 ° and a surface free energy of 15 to 35 mN / m. it can.

  In the biaxially oriented polyester film for molding of the present invention, the center line average roughness of the coating layer is required to be 1 to 50 nm. The centerline average roughness here refers to a value obtained by folding the roughness curve from the centerline and dividing the area obtained by the roughness curve and the centerline by the measurement length. In the present invention, five samples of 5 cm × 5 cm are sampled in the film width direction (250 mm), and each sample is evaluated.

  As an evaluation method, for example, for each sample with a laser microscope, six locations are extracted from the film edge at equal intervals, two-dimensional line roughness is measured, and the average value of the data is set as the centerline average roughness (total 30). Average value). In order to make the center line average roughness of the coating layer less than 1 nm, it is necessary to make the center line average roughness of the polyester film before coating less than 1 nm, which is not preferable because the handling property of the polyester film is lowered. . When the center line average roughness of the coating layer is larger than 50 nm, the coating layer may not be uniformly applied, and the uneven coating after molding is a defect. Even when the surface roughness after molding itself falls within the preferable range, a large defect such as a dent may occur, which is not preferable because the release property and non-adhesiveness may be deteriorated.

In order to make the center line average roughness of the coating layer 1 to 50 nm, it is effective to smooth the coated surface of the polyester film to be coated. If the polyester film surface is not smooth, it is difficult to apply the coating layer uniformly, and the surface of the coating layer, which is a thin film, may also be affected. For this purpose, a method for reducing the particle content of the polyester film and a method for reducing the particle size of the particles to be used can be used as long as the handleability is not impaired. The handleability as used herein refers to film winding property, film transportability during coating, continuous processability during film formation, and the like. Specifically, the center line average roughness of the polyester film is such that the particle content in the polyester film before coating is less than 5% by mass, preferably less than 4% by mass, based on 100% by mass of the entire polyester film. Is effective because it can be made 50 nm or less. However, if the content of the particles in the polyester film is less than 0.1% by mass, the center line average roughness of the polyester film may be less than 1 nm, which may reduce the handleability of the film. . Further, it is effective if the particle size of the particles used is 4 μm or less, preferably 2.5 μm or less. The particle diameter here means the number average diameter. The number average diameter can be obtained by the following formula.
D = ΣDi / N (Di: equivalent circle diameter of particles, N: number of particles)
The particle size can be measured by, for example, observing 100 particles at a magnification of 100000 times using a scanning electron microscope or the like, and taking the observed image into an image analyzer or the like. Thus, it can be measured by image analysis.

  Moreover, the centerline average roughness of a coating layer can be made into said range by improving the uniform application property of a coating layer. In order to improve the uniform application property of the coating layer, it is effective to set the surface free energy of the coating surface to 47 mN / m or more.

  Furthermore, it is preferable to laminate the coating layer in-line. In this case, the coating composition is applied after the longitudinal stretching, and the coating layer is uniformly stretched in order to perform drying, heat treatment and transverse stretching in the tenter. It is effective to make the center line average roughness of the layer within the above range.

  A more preferable range of the center line average roughness is 2 to 30 nm, and 3 to 20 nm is most preferable.

  Moreover, the biaxially oriented polyester film for molding of the present invention requires that the center line average roughness of the coating layer after extending the film twice in an arbitrary direction at 23 ° C. is 1 to 50 nm. . The center line average roughness of the coating layer after stretching the film twice in any direction is larger than 50 nm, which means that the coating layer may be roughened by stretching the film twice. In addition, it is not preferable because releasability and non-adhesiveness are deteriorated. Moreover, in order to make it less than 1 nm, it is necessary to make centerline average roughness of the film before shaping | molding less than 1 nm, and since a handleability may fall, it is unpreferable. If the center line average roughness of the coating layer after stretching the film twice in any direction is 1 to 50 nm, the surface free energy of the coating layer after stretching twice is maintained at 15 to 35 mN / m. This is very preferable.

  The more preferable range of the center line average roughness of the coating layer after extending the film twice in an arbitrary direction at 23 ° C. is 2 to 30 nm, and most preferably 3 to 20 nm.

  The measurement of the center line average roughness of the coating layer after stretching the film twice is to prepare a sample in which the film is cut into a rectangular shape having a length of 150 mm and a width of 20 mm in one arbitrary direction and a direction perpendicular to the direction. Do it. Sampling is performed in 30 ° increments from any one direction, and 6 samples are collected. Using a tensile tester (Orientec Tensilon UCT-100), a tensile test is performed on each sample with an initial tensile chuck distance of 50 mm and a tensile speed of 300 mm / min. For each sample (six samples), use samples sampled from the center in the length direction to a length of 2 cm x a width of 1.5 cm. The value of each sample.

  For six sets of samples sampled in 30 ° increments from any one direction, if the centerline average roughness value after double expansion is included in the above range, the centerline average is temporarily measured in a certain direction. Even if the roughness is outside the above range, the coating layer after film formation is not rough, and excellent properties can be exhibited.

  In order to set the centerline average roughness of the coating layer after extending the film twice in an arbitrary direction at 23 ° C. to 1 to 50 nm, the coating layer must have excellent adhesion and molding followability. It is valid. In order to improve the adhesion of the coating layer, it is effective to set the surface free energy of the coating surface of the film to 47 mN / m or more and to introduce a crosslinked structure in the coating layer.

  Moreover, in order to improve shaping | molding followability, it is preferable that the thickness of a coating layer shall be 0.01-3 micrometers. Here, the thickness of the coating layer refers to the dry thickness after coating. If the coating layer is made 3 μm or more, the coating layer may be roughened or cracked during molding. On the contrary, if the thickness of the coating layer is less than 0.01 μm, the characteristics of the coating layer may not be sufficiently exhibited, which is not preferable. The layer thickness of the coating layer can be adjusted by adjusting the solid content concentration of the coating composition or stretching the film after coating. Further, for example, in the case of a metering bar coat, the thickness of the coating layer can be adjusted also by the count of the metal ring bar. A more preferable layer thickness of the coating layer is 0.05 to 1.5 μm, and most preferably 0.1 to 1 μm.

  Furthermore, in order to improve the molding followability, it is important to appropriately control the heat treatment conditions after applying the coating layer. If the heat treatment temperature is too low or the heat treatment time is too short, the adhesion and strength of the coating film may be lowered, resulting in poor molding followability. Further, if the heat treatment temperature is too high or the heat treatment time is too long, the coating film becomes hard and may have a structure that is difficult to stretch, which may reduce the molding followability. The heat treatment temperature is preferably 50 to 250 ° C, more preferably 80 to 245 ° C, and most preferably 150 to 240 ° C for shortening the coating process. Moreover, although preferable heat processing time changes also with heat processing temperature, it is 1-120 second, It is more preferable if it is 2-60 second, and 3-30 second is the most preferable from the point of economical efficiency.

  Further, as described above, improving the adhesion between the coating layer and the film is very important from the viewpoint of molding followability of the coating layer.

  The biaxially oriented polyester film for molding of the present invention has a center line average roughness of 1 to 200 at 200 ° C. after stretching 1.5 times in any one direction of the film and in a direction perpendicular to the direction. 50 nm is preferred. The measurement of the centerline average roughness of the coating layer after stretching 1.5 times in any one direction of the film and in a direction perpendicular to the direction at 200 ° C. is a combination of any one direction and the direction perpendicular thereto. Are measured for three combinations as follows. A film stretched at 200 ° C. (made by Toyo Seiki Seisakusho Co., Ltd.) is set in an arbitrary direction and in a direction perpendicular to that direction, a film cut into a size of 90 × 90 mm is set, and after preheating for 20 seconds In both directions, simultaneous biaxial stretching is simultaneously performed at a speed of 2000% / min. Three samples are taken in 30 ° increments from any one direction, and stretched as described above for each sample. From each sample (three samples) central portion, (arbitrary direction 10 cm) × (direction 10 cm perpendicular to it) Samples are sampled, and the center line average roughness is measured for each sample to determine the average value.

  About three sets of samples sampled in increments of 30 ° in (arbitrary direction 10 cm) × (direction 10 cm perpendicular to it), the centerline average roughness value after stretching 1.5 × 1.5 times at 200 ° C. If included in the above range, the roughness of the coating layer after film formation at high temperature is seen even if the centerline average roughness may be outside the above range in measurement in a certain direction. Therefore, excellent characteristics can be exhibited.

  If the center line average roughness of the coating layer after stretching 1.5 times in any one direction of the film and in one direction orthogonal to the direction at 200 ° C. is 1 to 50 nm, it is processed at high temperature. However, it is very preferable because the coating layer is hardly roughened and can exhibit excellent release properties and non-adhesive properties even after being molded into various shapes. When the center line average roughness of the coating layer after stretching 1.5 times in any one direction of the film and in the direction perpendicular to the direction at 200 ° C. is larger than 50 nm, the coating layer becomes rough during the heat forming. It may occur, and it is not preferable because releasability and non-adhesiveness are lowered. Moreover, in order to make it less than 1 nm, it is necessary to make centerline average roughness of the film before shaping | molding less than 1 nm, and since a handleability may fall, it is unpreferable.

  In order to make the center line average roughness of the coating layer after stretching 1.5 times in any one direction of the film and in a direction perpendicular to the direction at 200 ° C. within the above range, the adhesion of the coating layer It is very important to improve molding followability, and in addition, it is preferable to use a coating compound having high heat resistance. When the heat resistance of the coating compound is low, the surface may be deformed and roughened by heat during molding at a high temperature.

  Furthermore, in order to extend in an arbitrary direction and a direction perpendicular to that direction, the orientation of the film is preferably balanced. For example, if the film is significantly oriented in a certain direction, stress may be applied to the film and the coating layer when the film is stretched in the oriented direction, so that the surface may become rough.

  The biaxially oriented polyester film for molding of the present invention has no problem whether the coating layer is laminated only on one side or on both sides, but it is bonded to a substrate such as a metal plate, a resin sheet, paper, or wood. When using, it is preferable to laminate | stack only on one side, and it is preferable that a coating layer becomes the surface instead of a base material side. When the coating layer is on the substrate side, the adhesion to the substrate may be inferior, which is not preferable. Since the surface properties such as releasability and non-adhesiveness can be exhibited by using the coating layer on the surface side, this is a preferred embodiment.

  In this invention, it is preferable that the contact angle of a coating layer and water at the time of performing retort processing for 125 minutes at 125 degreeC and 0.12 MPa is 90-120 degree. The contact angle between the coating layer and water at 90 ° C. for 90 minutes at 125 ° C. and 0.12 MPa is 90 to 120 °, which means that the surface properties of the coating layer change before and after the retort treatment. It shows no. If there is no change in the surface properties of the coating layer before and after the retort treatment, for example, when the biaxially oriented polyester film for molding of the present invention is used for food containers, after performing the retort treatment as a sterilization treatment of the contents In addition, since non-adhesiveness can be exhibited, the contents can be easily taken out. By showing this resistance to retort treatment, the biaxially oriented polyester film for molding of the present invention is very preferable because applicable applications are dramatically increased.

  In order to set the contact angle after the retort treatment within the above range, it is preferable to use a crosslinking compound in combination with the coating compound and introduce a crosslinked structure into the coating layer.

  The more preferable range of the contact angle with water when performing retort heat treatment at 125 ° C., 0.12 MPa for 90 minutes is 95 to 120 °, and most preferably 97 to 120 °.

  The biaxially oriented polyester film for molding of the present invention preferably has a melting point of 246 to 270 ° C. from the viewpoint of heat resistance and resin handleability. If the melting point is less than 246 ° C., the heat resistance is inferior, so that the surface is roughened at 200 ° C. when stretched 1.5 times in any one direction of the film and in the direction perpendicular to the direction. This is not preferable. On the other hand, when the temperature is higher than 270 ° C., it may be inferior in adhesion to a base material such as a metal plate, a resin sheet, paper, or wood, so that it is not preferable. Here, the melting point of the biaxially oriented polyester film for molding of the present invention is an endothermic peak temperature expressed by a melting phenomenon when measured at a heating rate of 20 ° C./min using a differential scanning calorimeter (DSC). is there. When a polyester resin having a different composition is blended and used as a film, a plurality of endothermic peaks due to melting may appear. In this case, the endothermic peak temperature appearing at the highest temperature is determined as the biaxial for molding of the present invention. The melting point of the oriented polyester film. The melting point is more preferably 250 to 270 ° C. As a method for setting the melting point of the polyester film to such a temperature range, it is preferable to set the melting point in the range of 246 to 270 ° C. in the polyester resin stage used at the time of film formation, and even when a polyester resin having a different composition is used. In order to suppress a melting point drop due to a transesterification reaction between resins during melt kneading even when a polyester resin having a melting point of 246 ° C. or higher is used and a polyester resin having a low melting point is used. In order to deactivate the catalyst remaining in the resin in advance or to reduce the catalytic ability, a phosphorus compound is added. Further, by preparing a polyester resin having a low residual catalyst amount, the melting point can be adjusted to a range of 246 to 270 ° C.

The biaxially oriented polyester film for molding of the present invention is orthogonal to the stress F100 _A value at 100% elongation in any direction (A direction) of the film at 100 ° C. from the viewpoint of moldability and handleability. It is preferable that the stress F100 _B value at 100% elongation in the direction (B direction) is 20 to 110 MPa, respectively.

If the F100 _A value and the F100 _B value at 100 ° C. of the polyester film of the present invention are each 20 to 110 MPa, the film is bonded to the base material and then subjected to a molding process, or the film itself is molded. It is preferable because it is very excellent in moldability.

When the F100 _A value and the F100 _B value at 100 ° C. are greater than 110, even when the coating layer has good molding followability, stress during molding increases, and the coating layer becomes rough due to strain. This is not preferable. On the other hand, if the film itself is a film having good moldability such that the F100 _A value and the F100 _B value at 100 ° C. fall within the above ranges, if the molding followability of the coating layer is poor, In some cases, the F100 _A value and the F100 _B value at 100 ° C. of the biaxially oriented polyester film for molding do not fall within the preferable ranges, and the surface may be roughened.

Further, if the F100 _A value and the F100 _B value are set to be less than 20 MPa, the heat resistance of the film is lowered, and when heat is applied, the surface of the film becomes rough or the film becomes too low. In addition, it is not preferable because wrinkles are likely to occur during winding of the film and handling properties may be deteriorated.

  The biaxially oriented polyester film for molding of the present invention is excellent in molding followability of the coating layer in addition to the moldability of a single film, so it can be easily molded into various shapes, and the mold release property after molding. , Non-adhesiveness can be maintained. Moreover, since the waist of the film is held, it is excellent in heat resistance and handleability.

  In addition, in the polyester film of this invention, in order to make the stress at the time of 100% expansion | extension in 100 degrees C of arbitrary directions and the direction orthogonal to it into 20-110 MPa, it is preferable to manufacture with the preferable manufacturing method described later. In any direction, the F100 value is most preferably 20 to 110 MPa. However, in the present invention, even when there is a direction in which the F100 value does not indicate 20 to 110 MPa, there is one combination that satisfies the F100 value of 20 to 110 MPa. When it is also a pair, it exhibits excellent moldability.

As a method for setting the F100 _A value and the F100 _B value at 100 ° C. to 20 to 110 MPa, a method of controlling the orientation of the film according to the film forming conditions is preferably used. Furthermore, a technique for controlling the melting point and glass transition point of the polyester to be used, and the copolymer composition and copolymerization ratio can also be preferably used. From the viewpoint of productivity, a method of controlling according to the film forming conditions is preferable, and in particular, it can be achieved by setting the stretching ratio, stretching temperature, and stretching speed during stretching within the preferable ranges in the film production method described later.

For example, the F100 _A value and the F100 _B value tend to decrease by decreasing the stretching ratio or increasing the preheating temperature and stretching temperature during stretching.

The F100 _A value and the F100 _B value at 100 ° C. are more preferably 30 to 100 MPa, and most preferably 40 to 90 MPa.

  The biaxially oriented polyester film for molding of the present invention preferably has a film thickness of 5 to 100 μm in terms of moldability and handleability. When the film thickness is less than 5 μm, the shape retention may be inferior. Also, if the film thickness exceeds 100 μm, even if the deformation stress during thermoforming is reduced, the actual load increases, so there may be partial deformation or the temperature rise for the forming process. Since it takes time to reduce productivity, it is not preferable. A more preferable range of the film thickness is 8 to 50 μm, and most preferably 10 to 30 μm.

  Here, the polyester resin constituting the biaxially oriented polyester film for molding of the present invention is a general term for polymer compounds in which the main bond in the main chain is an ester bond, and usually includes a dicarboxylic acid component and a glycol component. It can be obtained by polycondensation reaction. Examples of the dicarboxylic acid component include terephthalic acid, isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, diphenyldicarboxylic acid, diphenylsulfonedicarboxylic acid, diphenoxyethanedicarboxylic acid, and 5-sodiumsulfoisophthalic acid. Aromatic dicarboxylic acid, oxalic acid, succinic acid, adipic acid, sebacic acid, dimer acid, maleic acid, fumaric acid and other aliphatic dicarboxylic acids, cyclohexyne dicarboxylic acid and other alicyclic dicarboxylic acids, p-oxybenzoic acid, etc. The oxycarboxylic acid of these can be mentioned.

  Examples of the glycol component include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-butanediol, 1,6-butanediol, Aliphatic glycols such as hexanediol, neopentyl glycol, diethylene glycol, polyethylene glycol, polypropylene glycol, polyoxyalkylene glycols such as polytetramethylene glycol, alicyclic glycols such as 1,4-cyclohexanedimethanol, bisphenol A, bisphenol S And aromatic glycols. Two or more of these dicarboxylic acid components and glycol components may be used in combination. The polyester used in the present invention may be one type of polyester or a blend of two or more types of polyester.

  Particularly preferred polyester is mechanical strength, workability, and thermal properties, with terephthalic acid or dimethyl terephthalate and ethylene glycol as the main constituents, which can be obtained by polycondensation reaction by esterification or transesterification. It is preferable because of its excellent humidity characteristics. Here, “mainly” means that the ethylene terephthalate component in the polyester is 30 mol% or more.

  In producing the polyester resin constituting the polyester film of the present invention, a reaction catalyst and an anti-coloring agent can be used. Examples of the reaction catalyst include alkali metal compounds, alkaline earth metal compounds, zinc compounds, lead compounds, manganese compounds, cobalt compounds, aluminum compounds, antimony compounds, and titanium compound germanium compounds. Although a compound etc. can be used, in this invention, it does not specifically limit to these.

  In general, it is preferable to add an antimony compound, a germanium compound and / or a titanium compound as a polymerization catalyst at an arbitrary stage before the production of the polyester is completed. As such a method, for example, when a germanium compound is taken as an example, a method of adding a germanium compound powder as it is, or a method of dissolving a germanium compound in a glycol component which is a starting material of polyester, and using it. Can do.

Examples of the germanium compound include germanium dioxide, germanium hydroxide hydrate, germanium alkoxide compounds such as germanium tetramethoxide and germanium ethyleneglycoxide, germanium phonoxide compounds, germanium phosphate, and phosphorous such as germanium phosphite. An acid-containing germanium compound, germanium acetate, or the like can be used. Of these, germanium dioxide is preferably used.

  The antimony compound is not particularly limited, and for example, an oxide such as antimony trioxide, antimony acetate and the like can be used. Further, the titanium compound is not particularly limited, but titanium tetraalkoxide such as titanium tetraethoxide and titanium tetrabutoxide can be preferably used.

  The biaxially oriented polyester film for molding of the present invention preferably contains particles having a number average particle diameter of 0.01 to 5 μm from the viewpoint of improving handleability and preventing scratches during processing. The number average particle diameter is more preferably 0.05 to 4 μm, and particularly preferably 0.1 to 3 μm, from the viewpoint of preventing scratches during processing and preventing missing particles. As particles to be added, for example, internal particles, inorganic particles, and organic particles can be preferably used. In the biaxially oriented polyester film of the preferred embodiment of the present invention, the particles are preferably 0.01 to 5% by mass, more preferably 0.03 to 3% by mass, and still more preferably 0.05 to the biaxially oriented polyester film. ˜2 mass%, particularly preferably 0.05 to 1 mass%. In addition, as described above, when particles are added only to a specific layer as a laminated film, the particle concentration of the layer to which the particles are added is preferably 0.01 to 5% by mass, and 0.05 to 1% by mass. Is particularly preferable.

  Examples of the method for precipitating internal particles on the polyester film of the present invention include, for example, JP-A-48-61556, JP-A-51-12860, JP-A-53-41355, and JP-A-54-. The technique described in Japanese Patent No. 90397 can be employed. Further, other particles described in Japanese Patent Publication No. 55-20496 and Japanese Patent Publication No. 59-204617 can be used in combination.

  The method for measuring the concentration of the contained particles is not particularly limited. For example, a solvent that dissolves the polyester and does not dissolve the inert particles is selected, and the inert particles are centrifuged from the polyester. The method of making it a density | concentration is mentioned. As the solvent, orthochlorophenol, hexafluoroisopropanol, m-cresol and the like are preferably used.

  Examples of the inorganic particles that can be contained in the polyester film of the present invention include wet and dry silica, colloidal silica, aluminum silicate, titanium oxide, calcium carbonate, calcium phosphate, barium sulfate, aluminum oxide, mica, kaolin, and clay. As the organic particles, particles containing styrene, silicone, acrylic acids, methacrylic acids, polyesters, divinyl compounds and the like as constituent components can be used. Among them, it is preferable to use inorganic particles such as wet and dry silica and alumina, and particles containing styrene, silicone, acrylic acid, methacrylic acid, polyester, divinylbenzene and the like as constituent components. Furthermore, these internal particles, inorganic particles, and organic particles may be used in combination of two or more.

  The method for producing the polyester film of the present invention is not particularly limited. For example, after drying the polyester resin as necessary, the polyester film is supplied to a melt extruder, extruded into a sheet form from a slit-shaped die, and applied by a method such as electrostatic application. There is a method in which the unstretched sheet is stretched after being brought into close contact with the casting drum, cooled and solidified to obtain an unstretched sheet.

  Such a stretching method may be simultaneous biaxial stretching or sequential biaxial stretching. That is, a method is employed in which an unstretched sheet is stretched and heat-treated in the longitudinal direction and the width direction of the film to obtain a film having a desired degree of plane orientation. Among these methods, the tenter method is preferable in terms of film quality, and after stretching in the longitudinal direction, a sequential biaxial stretching method in which the film is stretched in the width direction, or the longitudinal direction and the width direction are stretched almost simultaneously. The simultaneous biaxial stretching method is preferably used from the viewpoint of suppressing variation in the plane orientation coefficient and suppressing unevenness in thickness.

  In such a stretching method, the stretching ratio employed is preferably 1.6 to 4.2 times, more preferably 2.4 to 4.0 times in each direction. The stretching speed is desirably 100 to 200000% / min, and the stretching temperature can be any temperature as long as it is in the temperature range of the glass transition point of the polyester to the glass transition point + 100 ° C., preferably 80 to 170 ° C., particularly preferably, the stretching temperature in the longitudinal direction is 90 to 150 ° C., and the stretching temperature in the width direction is 100 to 150 ° C. In order to impart a very excellent moldability to the film, it is particularly preferable that the stretching temperature in the longitudinal direction is 100 to 130 ° C., particularly before the longitudinal stretching, at a high temperature of 100 ° C. or higher for about 1 to 100 seconds, It is preferable to stretch after preheating in the range where it does not crystallize from the viewpoints of excellent flatness by uniform stretching and expression of excellent moldability by suppressing uneven orientation. Further, the stretching may be performed a plurality of times in each direction.

  Furthermore, the film can be heat-treated after biaxial stretching. This heat treatment can be performed by any method such as in an oven or on a heated roll. The heat treatment temperature can be any temperature within the range of the stretching temperature to the melting point of the raw material, but is preferably a heat treatment temperature of 160 to 235 ° C. from the viewpoint of molding processability and impact resistance. If the temperature is lower than this temperature, the impact resistance is deteriorated. If the temperature is higher, the moldability may be deteriorated. Further, the heat treatment time can be arbitrarily set within a range not deteriorating other characteristics, but it is usually preferable to carry out for 1 to 30 seconds. Further, the heat treatment may be performed by relaxing the film in the longitudinal direction and / or the width direction.

  In addition, when the biaxially oriented polyester film for molding of the present invention is laminated with the coating layer in-line as described above, in the above production method, after coating before stretching, a method of performing simultaneous biaxial stretching, A method in which the film is coated uniaxially in the longitudinal direction and then coated in the width direction can be used.

  In the biaxially oriented polyester film for molding of the present invention, additives such as an antistatic agent, a heat stabilizer, an antioxidant, a crystal nucleating agent, a weathering agent, and an ultraviolet absorber are used to the extent that the object of the present invention is not impaired. be able to. Further, surface unevenness processing such as embossing and sand mat processing, or surface treatment such as corona discharge treatment, plasma treatment, and alkali treatment may be performed as necessary. In addition, the biaxially oriented polyester film for molding of the present invention has an easy adhesion treatment agent, an antistatic agent, a water vapor / gas barrier agent (such as polyvinylidene chloride), a release agent, an adhesive, an adhesive, a flame retardant, an ultraviolet absorber, It may be coated and printed with matting agents, pigments, dyes, etc., for the purposes of shielding metals, compounds such as aluminum, aluminum oxide, silicon oxide, palladium, etc., water vapor / gas barrier, surface conductivity, infrared reflection, etc. You may vacuum-deposit and the objective and the method are not limited to the above.

  The biaxially stretched polyester film for molding of the present invention can be suitably used for molding. For example, it is subjected to molding from pasting to a base material, or the film itself is molded and used as a container. be able to. In particular, since it is excellent in releasability and non-adhesiveness with the contents, it can be suitably used as a metal plate laminating film for preserving food.

(Evaluation of the physical properties)
The physical properties and characteristics of the polymer and film were measured and evaluated by the following methods.

(1) Contact angle with water Using a contact angle meter (CA-D type manufactured by Kyowa Interface Chemical Co., Ltd.) for a sample conditioned at 23 ° C. and 65% RH for 24 hours, The static contact angle of was measured. A sample size of 10 cm × 10 cm was used, the sample was measured 10 times, and the average value was used as the contact angle of the sample.

  The contact angle after the heat treatment was also measured in the same manner as described above. The heat treatment was performed by attaching the film to a 12 cm × 12 cm metal frame with a double-sided tape and fixing it in a hot air oven at 180 ° C. for 120 minutes. The retort treatment was similarly fixed to a metal frame, and was performed for 90 minutes under the conditions of 125 ° C. and 0.12 MPa in a sterilizer.

  About the sample after heat processing and the retort process, it cut out to the magnitude | size of 10 cm x 10 cm from the metal frame, measured 10 times each, and made the average value the contact angle of the sample.

(2) Surface free energy In the same manner as in (1), the static contact angles with water, ethylene glycol, formamide, and methylene iodide were measured, and the following surface tension components of each liquid in Table 1 were used. Simultaneous equations were established (respective measurement solutions of water, ethylene glycol, formamide, and methylene iodide were changed to 1, 2, 3, and 4, and L in Table 1 was replaced with 1, 2, 3, and 4). From this equation, using “FindMinimum” (command for searching a local minimum value of a function composed of complex numbers) of numerical calculation software “Mathematica”, γ _s ^d , γ _s ^D , γ _s ^h Was determined as the most probable solution of this equation, and this was defined as the surface free energy of the measured film surface.

(Γ _s ^d · γ ₁ ^d ) ^1/2 + (γ _s ^d · γ ₁ ^p ) ^1/2 + (γ _s ^h · γ ₁ ^h ) ^1/2 = γ ₁ (1 + cos θ ₁ ) / 2
(Γ _s ^d · γ ₂ ^d ) ^1/2 + (γ _s ^d · γ ₂ ^p ) ^1/2 + (γ _s ^h · γ ₂ ^h ) ^1/2 = γ ₂ (1 + cos θ ₂ ) / 2
(Γ _s ^d · γ ₃ ^d ) ^1/2 + (γ _s ^d · γ ₃ ^p ) ^1/2 + (γ _s ^h · γ ₃ ^h ) ^1/2 = γ ₃ (1 + cosθ ₃ ) / 2
(Γ _s ^d · γ ₄ ^d ) ^1/2 + (γ _s ^d · γ ₄ ^p ) ^1/2 + (γ _s ^h · γ ₄ ^h ) ^1/2 = γ ₄ (1 + cos θ ₄ ) / 2.

(3) Double-extension of film in arbitrary direction A sample was prepared by cutting the film into a rectangular shape having a length of 150 mm and a width of 20 mm in an arbitrary direction and a direction orthogonal to the direction. Similarly, sampling was performed in 30 ° C. increments from any direction, and 6 samples were collected. Using a tensile tester (Orientec Tensilon UCT-100), the initial tensile chuck distance was set to 50 mm, the tensile speed was set to 300 mm / min, and each sample was subjected to a tensile test at 23 ° C. and stretched by 100%.

(4) Any one direction of the film and 1.5 times extension in the direction orthogonal to the direction Any one direction and its direction on a film stretcher (manufactured by Toyo Seiki Seisakusho) heated to 200 ° C Set a film cut to a size of 90 x 90 mm in the direction perpendicular to, and after preheating for 20 seconds, stretch it by simultaneously biaxial stretching at a speed of 2000% / min in both directions at a rate of 1.5 times I let you. Sampling was performed in 30 ° increments from any one direction, 3 samples were collected, and each sample was elongated.

(5) Centerline average roughness Using an ultra-deep shape measuring microscope VK-8500 (manufactured by Keyence Corporation), the coating layer side two-dimensional line roughness was measured and calculated from the data. The measurement sample used was a sample of five 5 cm × 5 cm samples in the film width direction (250 mm). About each sample, six places were extracted from the film edge at equal intervals, and the measurement was performed (a total of 30 places). The measurement was performed with the objective lens 100 times, the measurement pitch 0.01 μm, the length measurement 100 μm, and the cut-off 0.08 mm.

  In addition, the measurement of the centerline average roughness of the coating layer after the film was stretched twice in an arbitrary direction was measured from the central part in the length direction for each sample (6 samples) prepared in (3). Samples sampled to 2 cm × width 1.5 cm were used, and each 6 samples were extracted at 5 locations, and the average value was taken as the value of each sample.

  In addition, the measurement of the center line average roughness of the coating layer after stretching 1.5 times in any one direction of the film and in a direction perpendicular to the direction at 200 ° C. was performed by measuring each sample prepared in (4) ( (3 samples) Samples of (arbitrary direction 10 cm) × (direction 10 cm perpendicular to it) were sampled from the central portion, 10 samples were extracted from each sample, and the average value was taken as the value of each sample.

(6) Coating layer thickness The cross section of the film was photographed with a transmission electron microscope (TEM H7100, manufactured by Hitachi, Ltd.) by an ultrathin section method, and the thickness of the coating layer was measured. The measurement was observed at any magnification of 20000 at any five locations in the center in the film width direction, and the average value was taken as the thickness of the coating layer.

(7) Melting | fusing point of film It measured using the differential scanning calorimeter (the Seiko Denshi Kogyo make, RDC220). When 5 mg of the sample is used as a sample and there are multiple endothermic peaks with the endothermic peak temperature at 25 ° C. up to 300 ° C. as the melting point, the peak temperature of the endothermic peak on the highest temperature side is the melting point It was.

(8) Stress at 100% elongation A film was cut into a rectangular shape having a length of 150 mm and a width of 10 mm in an arbitrary direction and a direction perpendicular thereto. Using a tensile tester (Orientec Tensilon UCT-100), the tensile test was performed in the longitudinal direction and the width direction of the film at an initial tensile chuck distance of 50 mm and a tensile speed of 300 mm / min. For the measurement, a film sample was set in a constant temperature layer set to 100 ° C. in advance, and a tensile test was performed after 90 seconds of preheating. Read the load applied to the film when the sample is stretched 100% (when the distance between chucks is 100 mm), and divide by the cross-sectional area (film thickness x 10 mm) of the sample before the test. F100 value). In addition, the measurement was performed 5 times for each sample and each direction, and the average value was evaluated.

(9) Releasability Acrylic adhesive tape (Nitto Denko Co., Ltd. Nitto polyester tape 31B) having a width of 19 mm is applied to the coating layer surface of the film sample that has been stretched twice in any direction by the method of (3). Attached rubber roller (linear pressure 2 kg / cm) was pressure-bonded to a length of 200 mm. The pressure-sensitive adhesive tape was peeled off at 25 ° C. and 65% RH atmosphere at a peeling angle of 90 degrees, and evaluated according to the following criteria.
Excellent: It was able to peel without any resistance.
Good: Peeled almost without resistance.
Good: I felt some resistance, but I could peel off without any problems.
Not possible: A strong resistance was felt and it was difficult to peel off.

(10) Non-adhesiveness A film sample stretched 1.5 times in the longitudinal direction and width direction by the method of (4) was bonded to an ABS sheet (200 × 300 mm) stored in a hot air oven at 200 ° C. for 2 minutes. After laminating the film with a laminator (180 ° C., 1 m / min, 0.3 MPa) through the sheet, the film was placed in a bat filled with commercially available minced meat and cured at 40 ° C. and 65 RH% for 72 hours. The ABS sheet laminated with was taken out, and the amount of adhesion (weight) to the film surface was determined according to the following criteria. In addition, the adhesive sheet was produced by melt-pressing (120 degreeC, 4 Mpa, 1 minute) (Nippon Synthetic Chemical Industry Co., Ltd. Polyester SP170).
Excellent: 0-10%
Good: 10-30%
Yes: 30-50%
Impossibility: 50 to 100%.

(11) Formability Using a far-infrared heater heated to 200 ° C, the surface temperature is heated to 180 ° C, and vacuum forming is performed using a cylindrical mold (bottom diameter 50 mm) to form a film. did. The state of being molded along the cylindrical mold was evaluated according to the following criteria using the degree of molding (drawing ratio: molding height / bottom diameter).
Excellent: Molding was possible at a drawing ratio of 0.5 or more.
Good: Molding was possible with a drawing ratio of 0.5 to 0.3.
Good: Molding was possible at a drawing ratio of 0.2 to 0.3.
Not possible: tearing occurred and molding could not be performed with a drawing ratio of 0.2.

(12) Handleability A film having a width of 250 mm was wound around a core having a diameter of 100 mm and a length of 400 mm at a speed of 20 m / min, and the ease of winding at that time was evaluated according to the following criteria to be handled.
Yu: Wrinkles and winding did not occur, and it was wound without any problems.
Good: The film was easy to wrinkle and required caution, but could be wound up without any problem.
Good: The film wrinkled, but could be wound up without any problem.
Impossible A: The film slipped and could not be wound on the core.
Impossible B: Wrinkles were generated in large quantities, and the film was further blocked.

(Production method of polyester)
The polyester resins used in the following examples and comparative examples were produced as follows.

(PET)
To a mixture of 100 parts by weight of dimethyl terephthalate and 70 parts by weight of ethylene glycol, 0.09 parts by weight of magnesium acetate and 0.03 parts by weight of antimony trioxide are added, the temperature is gradually raised, and finally Conducted transesterification while distilling methanol at 220 ° C. Subsequently, 0.020 part by mass of an 85% aqueous solution of phosphoric acid was added to the transesterification reaction product, and then transferred to a polycondensation reaction kettle. Polyethylene in which the reaction system is gradually depressurized while being heated in a polymerization kettle and subjected to a polycondensation reaction at 290 ° C. under a reduced pressure of 1 hPa, and an intrinsic viscosity of 0.65 and 2 mol% of diethylene glycol as a by-product are copolymerized. A terephthalate resin was obtained.

(PBT)
A mixture of 100 parts by mass of terephthalic acid and 110 parts by mass of 1,4-butanediol was heated to 140 ° C. under a nitrogen atmosphere to obtain a homogeneous solution, and then 0.054 parts by mass of tetra-n-butyl orthotitanate. Then, 0.054 parts by mass of monohydroxybutyltin oxide was added to carry out an esterification reaction. Next, 0.066 parts by mass of tetra-n-butyl orthotitanate was added and a polycondensation reaction was performed under reduced pressure to prepare a polybutylene terephthalate resin having an intrinsic viscosity of 0.88. Thereafter, crystallization was performed at 140 ° C. in a nitrogen atmosphere, followed by solid phase polymerization at 200 ° C. for 6 hours in a nitrogen atmosphere to obtain a polybutylene terephthalate resin (PBT) having an intrinsic viscosity of 1.22.

(PTT)
Using 100 parts by weight of dimethyl terephthalate and 80 parts by weight of 1,3-propanediol as a catalyst in a nitrogen atmosphere, the temperature was gradually raised from 140 ° C. to 230 ° C., and the ester exchange reaction was carried out while distilling methanol. went. Further, a polycondensation reaction was carried out for 3 hours under a constant temperature of 250 ° C. to obtain a polytrimethylene terephthalate resin having an intrinsic viscosity [η] of 0.86.

(PET-G)
To a mixture of 100 parts by weight of dimethyl terephthalate, 70 parts by weight of ethylene glycol and 7 parts by weight of 1,4-cyclohexanedimethanol, 0.04 parts by weight of manganese acetate is added, and the temperature is gradually raised. Transesterification was carried out while distilling methanol at 0 ° C. Next, 0.045 parts by mass of 85% phosphoric acid aqueous solution and 0.01 parts by mass of germanium dioxide were added, and the temperature was gradually raised and reduced. Finally, the temperature was raised to 275 ° C. and 1 hPa, and the intrinsic viscosity was reduced. The polycondensation reaction was carried out until 0.67, and then discharged into a strand, cooled, and cut to obtain a polyethylene terephthalate resin copolymerized with 4 mol% of 1,4-cyclohexanedimethanol. The polymer was cut into cubes having a diameter of 3 mm, and solid phase polymerization was performed using a rotary vacuum polymerization apparatus under a reduced pressure of 1 hPa at 225 ° C. until the intrinsic viscosity became 0.8. Then, 30 mol of 1,4-cyclohexanedimethanol copolymerized polyethylene terephthalate (Eastster 6763 manufactured by Eastman Chemical Co.) was uniformly mixed at 85:15. Thereafter, it was supplied to a biaxial vent type extruder, melt-kneaded, extruded into a strand, cooled in water, cut into a chip, and copolymerized with 7.9 mol% of 1,4-cyclohexanedimethanol. G was obtained.

(Particle Master)
In addition, 0.04 parts by mass of manganese acetate was added to a mixture of 100 parts by mass of dimethyl terephthalate and 70 parts by mass of ethylene glycol, the temperature was gradually raised, and finally methanol was distilled at 220 ° C. Went. Subsequently, 0.025 mass part of 85% phosphoric acid aqueous solution and 0.02 mass part of germanium dioxide were added. Further, an ethylene glycol slurry of wet silica agglomerated particles having an average particle size of 2.2 μm is added so that the particle concentration becomes 2% by mass, the temperature is gradually raised and reduced, and finally the temperature is raised to 290 ° C. and 1 hPa. The pressure was reduced and the polycondensation reaction was carried out until the intrinsic viscosity became 0.63, and then the strands were discharged, cooled, and cut to obtain a particle master.

(Manufacturing method of coating composition)
The coating composition used in the following experiments was prepared as follows.

(Coating composition A)
100 parts by mass of an alkenyl group-containing organopolysiloxane / hydrogenpolysiloxane addition reaction type silicone emulsion (X-52-195) manufactured by Shin-Etsu Silicone Co., Ltd., 5 parts by mass of a catalyst (CAT-PM-10), isopropyl alcohol 100 Part by mass and 400 parts by mass of water were mixed to obtain a coating composition A.

(Coating composition B)
100 parts by mass of addition reaction type silicone emulsion (X-52-195) of alkenyl group-containing organopolysiloxane / hydrogenpolysiloxane manufactured by Shin-Etsu Silicone Co., Ltd., 3 parts by mass of catalyst (CAT-PM-10), Nippon Vinegar -300 mass parts of polyvinyl alcohol (JP-18) 5 mass% aqueous solution by Poval Co., Ltd. was mixed, and the coating composition B was obtained.

(Coating composition C)
100 parts by mass of an alkenyl group-containing organopolysiloxane / hydrogenpolysiloxane addition reaction type silicone emulsion (X-52-195) manufactured by Shin-Etsu Silicone Co., Ltd., 1 part by mass of a catalyst (CAT-PM-10), isopropyl alcohol 200 Part by mass and 1000 parts by mass of water were mixed to obtain a coating composition C.

(Coating composition D)
100 parts by mass of silicone emulsion (SILCOLEASE902) manufactured by Arakawa Chemical Industries, Ltd., 10 parts by mass of catalyst (CATA903), and 600 parts by mass of water were mixed to obtain a coating composition D.

(Coating composition E)
100 parts by mass of addition reaction type silicone dispersion (LTC750A) of alkenyl group-containing organopolysiloxane / hydrogenpolysiloxane manufactured by Toray Dow Corning Silicone Co., Ltd., 1 part by mass of catalyst (SRX-212), 500 parts by mass of toluene Mixing was performed to obtain a coating composition E.

(Coating composition F)
An acrylic emulsion (Nicazole Y-9105) manufactured by Nippon Carbide Industries Co., Ltd. was used as the coating composition F.

(Coating composition G)
A coating composition G was prepared by mixing 100 parts by mass of Shin-Nakamura Chemical's long-chain alkyl acrylate (TR-7) with 60 parts by mass of water.

(Coating composition H)
A coating composition H was prepared by mixing 100 parts by mass of Shin-Nakamura Chemical's long-chain alkyl acrylate (TR-7), 50 parts by mass of water and 20 parts by mass of isopropyl alcohol.

(Coating composition I)
A coating composition I was obtained by mixing 100 parts by mass of a wax emulsion (KEK-T) manufactured by Guangei Chemical Industry Co., Ltd., 20 parts by mass of isopropyl alcohol, and 150 parts by mass of water.

(Coating composition J)
The coating composition J was a wax emulsion (KEK-T) manufactured by Guangei Chemical Industry Co., Ltd.

(Coating composition K)
On the other hand, 100 parts by mass of non-silicone emulsion-type back release agent (Pyroyl 406) manufactured by Ogyo Kogyo Co., Ltd. and 500 parts by mass of water were mixed to obtain a coating composition K.

Example 1
PET and particle master are mixed at a mass ratio of 99: 1, dried in a vacuum dryer at 180 ° C for 4 hours, and after sufficiently removing moisture, supplied to a single screw extruder, melted at 280 ° C, and removal of foreign matters After the amount of extrusion was leveled, the sheet was discharged from a T-die onto a cooling drum whose temperature was controlled at 25 ° C. At that time, a wire-like electrode having a diameter of 0.1 mm was applied electrostatically and adhered to the cooling drum to obtain an unstretched film.

  Next, the film temperature is raised with a heating roll before stretching in the longitudinal direction, and finally the film is stretched 3.0 times in the longitudinal direction at a film temperature of 105 ° C, and immediately cooled with a metal roll whose temperature is controlled at 40 ° C. did. The uniaxially stretched film was subjected to corona discharge treatment in the air, and the surface free energy of the polyester film was set to 52 mN / m. The treated surface was coated with the coating composition A using a metalling bar (# 6). Next, the film was stretched 3.0 times in the width direction at a preheating temperature of 95 ° C. and a stretching temperature of 120 ° C. with a tenter-type transverse stretching machine, and the temperature was kept at 210 ° C. for 5 seconds while relaxing 4% in the width direction. A biaxially oriented polyester film in which a heat treatment was performed and a coating layer having a film thickness of 15 μm was laminated was obtained.

(Example 2)
Example 1 except that PET and particle master were mixed at a mass ratio of 97: 3, the coating composition B was used, and the draw ratio in the longitudinal direction was 3.1 times and the draw ratio in the width direction was 3.1 times. In the same manner as above, a biaxially oriented polyester film in which a coating layer having a film thickness of 12 μm was laminated was obtained.

(Example 3)
Using coating composition G, the film temperature during stretching in the longitudinal direction was 95 ° C., the stretching ratio was 3.1 times, and the stretching ratio in the width direction was 3.2 times, as in Example 2. A biaxially oriented polyester film in which a coating layer having a film thickness of 20 μm was laminated was obtained.

(Example 4)
PET, PBT and particle master are mixed at a mass ratio of 77: 20: 3, dried in a vacuum dryer at 180 ° C for 3 hours to sufficiently remove moisture, then supplied to a single screw extruder and melted at 280 ° C. After removing the foreign matter and leveling the extrusion amount, it was discharged from a T-die onto a cooling drum whose temperature was controlled at 25 ° C. in a sheet form. At that time, a wire-like electrode having a diameter of 0.1 mm was applied electrostatically and adhered to the cooling drum to obtain an unstretched film.

  Next, the film temperature is raised with a heating roll before stretching in the longitudinal direction, and finally the film is stretched 3.0 times in the longitudinal direction at a film temperature of 100 ° C, and immediately cooled with a metal roll whose temperature is controlled at 40 ° C. did. The uniaxially stretched film was subjected to corona discharge treatment in the air, and the surface free energy of the polyester film was set to 52 mN / m. The treated surface was coated with the coating composition E using a metalling bar (# 6). Next, the film was stretched 3.0 times in the width direction at a preheating temperature of 95 ° C. and a stretching temperature of 110 ° C. with a tenter-type transverse stretching machine, and while being relaxed by 4% in the width direction in the tenter, the temperature was maintained at 230 ° C. for 5 seconds. Heat treatment was performed to obtain a biaxially oriented polyester film having a film thickness of 15 μm.

(Example 5)
PET, PET-G and particle master are mixed at a mass ratio of 16: 80: 4, dried in a vacuum dryer at 180 ° C. for 4 hours, and after sufficiently removing moisture, supplied to a single screw extruder at 280 ° C. After melting, removing foreign matter, and leveling the amount of extrusion, it was discharged from a T-die onto a cooling drum whose temperature was controlled at 25 ° C. in a sheet form. At that time, a wire-like electrode having a diameter of 0.1 mm was applied electrostatically and adhered to the cooling drum to obtain an unstretched film.

  Next, the film temperature is raised with a heating roll before stretching in the longitudinal direction, and finally the film is stretched 3.0 times in the longitudinal direction at a film temperature of 100 ° C, and immediately cooled with a metal roll whose temperature is controlled at 40 ° C. did. The uniaxially stretched film was subjected to corona discharge treatment in the air, and the surface free energy of the polyester film was set to 52 mN / m. The treated surface was coated with the coating composition I using a metalling bar (# 10). Next, the film was stretched 3.0 times in the width direction at a preheating temperature of 95 ° C. and a stretching temperature of 110 ° C. with a tenter-type transverse stretching machine, and the temperature was kept at 220 ° C. for 5 seconds while relaxing 4% in the width direction. Heat treatment was performed to obtain a biaxially oriented polyester film having a film thickness of 12 μm.

(Example 6)
PET and particle master are mixed at a mass ratio of 97: 3, dried in a vacuum dryer at 180 ° C for 4 hours, and after sufficiently removing moisture, supplied to a single screw extruder, melted at 280 ° C, and removed foreign matter. After the amount of extrusion was leveled, the sheet was discharged from a T-die onto a cooling drum whose temperature was controlled at 25 ° C. At that time, a wire-like electrode having a diameter of 0.1 mm was applied electrostatically and adhered to the cooling drum to obtain an unstretched film.
Next, before stretching in the longitudinal direction, the film temperature is raised with a heating roll, and finally stretched 3.1 times in the longitudinal direction at a film temperature of 105 ° C., and then a preheating temperature of 95 ° C. with a tenter type transverse stretching machine, A biaxially oriented polyester film having a film thickness of 12 μm is stretched 3.1 times in the width direction at a stretching temperature of 110 ° C. and subjected to a heat treatment at 210 ° C. for 5 seconds while relaxing 4% in the width direction in the tenter. Obtained. This biaxially oriented polyester film is subjected to corona discharge treatment in the air, the surface free energy is 54 mN / m, the coating composition E is coated using a metalling bar (# 8), and a hot air dryer at 120 ° C. The film was dried for 60 seconds to obtain a biaxially oriented polyester film having a coating layer laminated thereon.

(Example 7)
PET and particle master were mixed at a mass ratio of 99.8: 0.2, coating composition H was used, except that the stretching ratio in the longitudinal direction was 3.3 times and the stretching ratio in the width direction was 3.2 times. In the same manner as in Example 1, a biaxially oriented polyester film in which a coating layer having a film thickness of 12 μm was laminated was obtained.

(Example 8)
PET, PBT, PTT and particle master are mixed at a mass ratio of 67: 15: 15: 3, and the coating composition K is used. The stretching temperature in the longitudinal direction is 100 ° C., the stretching temperature in the width direction is 110 ° C., and the heat treatment temperature is set. A biaxially oriented polyester film in which a coating layer having a film thickness of 20 μm was laminated was obtained in the same manner as in Example 1 except that the temperature was 240 ° C.

Example 9
A biaxially oriented polyester film in which a coating layer having a film thickness of 15 μm is laminated in the same manner as in Example 1 except that PET and a particle master are mixed at a mass ratio of 99.6: 0.4 and the coating composition C is used. Got.

(Example 10)
PET, PBT, PTT, and particle master were mixed at a mass ratio of 69: 20: 10: 1 and coating composition B was used, except that a coating layer having a film thickness of 15 μm was laminated in the same manner as in Example 8. An axially oriented polyester film was obtained.

Example 11
A biaxially oriented polyester film in which a coating layer having a film thickness of 12 μm is laminated in the same manner as in Example 8 except that PET, PBT and particle master are mixed at a mass ratio of 67: 30: 3 and the coating composition D is used. Got.

Example 12
A biaxially oriented polyester film in which a coating layer having a film thickness of 15 μm is laminated in the same manner as in Example 8 except that PET, PTT, and a particle master are mixed at a mass ratio of 68: 30: 2 and the coating composition G is used. Got.

(Comparative Example 1)
PET frozen in a powder form and carnauba wax are mixed at a mass ratio of 98: 2, mixed uniformly, then fed to a twin-screw vent type extruder, melt-kneaded, extruded into a strand, cooled in water Thereafter, it was cut into chips to obtain a wax master chip.

  PET, carnauba wax master and particle master were mixed at a mass ratio of 47: 50: 3, dried at 180 ° C. for 4 hours in a vacuum dryer to sufficiently remove moisture, and then supplied to a single screw extruder, 280 ° C. Then, after removing the foreign matter and leveling the amount of extrusion, it was discharged from a T-die onto a cooling drum whose temperature was controlled at 25 ° C. in a sheet form. At that time, a wire-like electrode having a diameter of 0.1 mm was applied electrostatically and adhered to the cooling drum to obtain an unstretched film.

  Next, the film temperature is raised with a heating roll before stretching in the longitudinal direction, and finally the film is stretched 3.3 times in the longitudinal direction at a film temperature of 95 ° C and immediately cooled with a metal roll whose temperature is controlled at 40 ° C. did. Next, the film was stretched 3.3 times in the width direction at a preheating temperature of 90 ° C. and a stretching temperature of 100 ° C. with a tenter type horizontal stretching machine, and the temperature was maintained at 230 ° C. for 5 seconds while relaxing 4% in the width direction. Heat treatment was performed to obtain a biaxially oriented polyester film having a film thickness of 12 μm.

(Comparative Example 2)
PET and particle master are mixed at a mass ratio of 97: 3, dried at 180 ° C for 4 hours in a vacuum dryer to sufficiently remove moisture, then supplied to a single screw extruder, melted at 280 ° C, and removed foreign matter After the amount of extrusion was leveled, the sheet was discharged from a T-die onto a cooling drum whose temperature was controlled at 25 ° C. At that time, a wire-like electrode having a diameter of 0.1 mm was applied electrostatically and adhered to the cooling drum to obtain an unstretched film.

  Next, the film temperature is raised with a heating roll before stretching in the longitudinal direction, and finally the film is stretched 3.3 times in the longitudinal direction at a film temperature of 95 ° C and immediately cooled with a metal roll whose temperature is controlled at 40 ° C. did. Next, the film was stretched 3.3 times in the width direction at a preheating temperature of 90 ° C. and a stretching temperature of 100 ° C. with a tenter type horizontal stretching machine, and the temperature was maintained at 230 ° C. for 5 seconds while relaxing 4% in the width direction. Heat treatment was performed to obtain a biaxially oriented polyester film having a film thickness of 15 μm. This biaxially oriented polyester film was subjected to corona discharge treatment in air, the surface free energy was 54 mN / m, the coating composition J was coated using a metalling bar (# 5), and a hot air dryer at 120 ° C. The film was dried for 60 seconds to obtain a biaxially oriented polyester film having a coating layer laminated thereon.

(Comparative Example 3)
A biaxially oriented polyester film in which a coating layer having a film thickness of 15 μm was laminated was obtained in the same manner as in Example 4 except that the coating composition F was used.

(Comparative Example 4)
PET and particle master are mixed at a mass ratio of 94: 6, and the coating composition B is used. The stretching ratio in the longitudinal direction is 3.3 times, the stretching temperature is 100 ° C., and the stretching ratio in the width direction is 3.2 times. A biaxially oriented polyester film in which a coating layer having a film thickness of 15 μm was laminated was obtained in the same manner as in Example 1 except that.

(Comparative Example 5)
After PET is dried at 180 ° C. for 4 hours in a vacuum dryer to sufficiently remove moisture, it is supplied to a single screw extruder, melted at 280 ° C., foreign matter is removed, and the amount of extrusion is leveled. The sheet was discharged from a die onto a cooling drum whose temperature was controlled at 25 ° C. At that time, a wire-like electrode having a diameter of 0.1 mm was applied electrostatically and adhered to the cooling drum to obtain an unstretched film.

  Thereafter, using the coating composition J, the stretching ratio in the longitudinal direction was 3.0 times, the stretching temperature was 100 ° C., and the stretching ratio in the width direction was 3.8 times. A biaxially oriented polyester film in which a coating layer having a film thickness of 15 μm was laminated was obtained.

* Surface free energy and centerline average roughness after stretching twice were measured for 6 samples stretched in an arbitrary direction, and only the maximum and minimum values were listed.
** Centerline average roughness after stretching 1.5 x 1.5 times was measured for three sets of samples stretched in an arbitrary direction and a direction perpendicular thereto, and only the maximum and minimum values of them were measured. Described.
** F100 _A and F100 _B were measured for three sets of samples extended in an arbitrary direction and a direction orthogonal thereto, and only the maximum and minimum values were listed.

  Since the biaxially oriented polyester film for molding of the present invention has a large contact angle with water and low surface free energy, it is excellent in releasability and non-adhesiveness and can be used for various applications. Moreover, since it is also excellent in moldability and exhibits excellent release properties and non-adhesiveness after molding, after high-temperature heat treatment and retort treatment, it can be used particularly for container molding applications such as foods.

Claims (14)

A coating layer having a surface free energy of 15 to 35 mN / m is laminated on at least one side of the polyester film,
The center line average roughness of the coating layer is 1 to 50 nm,
And the biaxially-oriented polyester film for shaping | molding whose centerline average roughness of the coating layer after extending | stretching a film twice in arbitrary directions at 23 degreeC is 1-50 nm. The contact angle of the coating layer with water is 90 to 120 °,
The biaxially oriented polyester film for molding according to claim 1, wherein the contact angle with water after heat treatment at 180 ° C for 120 minutes is 90 to 120 °. 2. The molding layer according to claim 1, wherein the center line average roughness of the coating layer after stretching 1.5 times in any one direction of the film and in a direction orthogonal to the direction at 200 ° C. is 1 to 50 nm. Axial-oriented polyester film. The biaxially oriented polyester film for molding according to claim 1, wherein the surface free energy of the coating layer after extending the film twice in any direction at 23 ° C is 15 to 35 mN / m. The biaxially oriented polyester film for molding according to claim 1, wherein the coating layer comprises a silicone compound. The biaxially oriented polyester film for molding according to claim 5, wherein the silicone compound comprises a main agent and a crosslinking agent. The biaxially oriented polyester film for molding according to claim 6, wherein the silicone compound is an addition reaction of an organopolysiloxane containing an alkenyl group as a main component and a hydrogen polysiloxane as a crosslinking agent. The biaxially oriented polyester film for molding according to claim 1, wherein the coating layer has a thickness of 0.01 to 3 μm. The biaxially oriented polyester film for molding according to claim 1, wherein the contact angle between the coating layer and water when subjected to retort treatment at 125 ° C, 0.12 MPa for 90 minutes is 90 to 120 °. The biaxially oriented polyester film for molding according to claim 1, which has a melting point of 246 to 270 ° C. The 100% elongation stress F100 _A value in an arbitrary direction (A direction) of the film at 100 ° C. and the 100% elongation stress F100 _B value in a direction perpendicular to the direction (B direction) are 20 to 110 MPa, respectively. The biaxially oriented polyester film for molding according to claim 1. The biaxially oriented polyester film for molding according to claim 1, which is used for metal plate laminating. The biaxially oriented polyester film for molding according to claim 1, which is used for container molding. 2. The method for producing a biaxially oriented polyester film for molding according to claim 1, wherein the coating surface is coated with an emulsion type coating agent after the surface free energy of the coating surface is set to 47 mN / m or more. A method for producing a biaxially oriented polyester film.